Abstract: Cells made ischemic rapidly manifest many distinct structural and functional alterations as a consequence of the depletion of their energy stores. In attempting to determine which of these are causally related to the eventual cell death, the authors have emphasized the relationship to the reversibility of the ischemic injury. Two phenomena have consistently characterized irreversibly in contrast to reversibly injured ischemic cells: the inability to restore mitochondrial function and evidence of plasma membrane damage. Studies in the authors' laboratory are reviewed that have focused on the pathogenesis, biochemical nature, and the relationship to irreversible cell injury of both of these alterations. A number of mitochondrial abnormalities are related to changes in long-chain acyl-CoA metabolism with inhibition of adenine nucleotide translocation and potentiation of a Ca2+-dependent increase in the permeability of the inner mitochondrial membrane. These changes are reversible upon reoxygenation only when the large increase in intracellular Ca2+ content that accompanies the phospholipid depletion from other cellular membranes is prevented. This disorder in phospholipid metabolism is felt to be the critical lesion that produces irreversible cell injury in ischemia. It affects the endoplasmic and sarcoplasmic reticular membranes of liver and myocardial cells, respectively, and probably the plasma membranes of both. It is prevented by pretreatment with chlorpromazine. An activation of endogenous phospholipases by an elevated, cytosolic free Ca2+ ion concentration is suggested as the mechanism underlying this phospholipid disturbance. The central role of intracellular Ca2+ in the initiation and functional consequences of ischemic cell injury are emphasized.

Abstract: Forty-three tumors were investigated by means of immunofluorescence with the use of antibodies against the following different classes of intermediate-sized (10 nm) filament proteins: 1) cytokeratins, 2) vimentin, and 3) desmin. In general, the immunologic features of tumor-cell intermediate filaments are those present in their tissue of origin. It can be seen, therefore, that, during neoplastic transformation, there are no major changes in the synthesis of the type of intermediate filament proteins when compared to normal tissues. Immunologic identification of these proteins furnishes the surgical pathologist with a quick and clear-cut way to differentiate tumors of mesenchymal origin from epithelial neoplasms, and in particular to distinguish between malignant lymphomas and lymph node metastases of undifferentiated carcinomas.

Abstract: 1-O-Alkyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine aggregates and degranulates platelets and polymorphonuclear neutrophils. Here, the bioactivities of this platelet-activating factor, its 2-O-ethyl, and its 2-lyso derivatives were examined further. Each phospholipid aggregated and degranulated rabbit platelets and neutrophils with relative potencies of about 10,000 1,000, and 1, respectively. For rabbit neutrophils, and 2-O-acetyl compound was active in nanomolar and lower concentrations; required extracellular calcium and magnesium in order to induce aggregation; and required extracellular calcium and cytochlasin B in order to induce optimal degranulation. Furthermore the 2-O-acetyl and 2-O-ethyl compounds, in concentrations about tenfold higher than those required for rabbit neutrophils, aggregated and degranulated human neutrophils. With reference to these human neutrophil responses, degranulation required, and aggregation was dramatically enhanced by, cytochalasin B. The lysoanalog was unable to induce these response in the human cells. Thus, these lipids represent a novel class of neutrophil stimulants that closely resemble certain chemotactic factors (eg, C5a and synthetic oligopeptides) in their ability to aggregate and degranulate neutrophils and in the influences which calcium, magnesium and cytochalasin B have on their bioactions. Because platelet-activating factor circulates in the blood of rabbits and, perhaps, humans during anaphylaxis and is suspected of being involved in other syndromes such as serum sickness, this lipid may have unique biologic significance: it may act to recruit platelets and neutrophils into the lesions of these and similar pathologic syndromes.

Abstract: Previous studies from our laboratories have demonstrated that granulocytes (PMNs), when exposed to activated complement (C) (specifically C5a), will aggregate and be provoked to damage cultured endothelial cells in vitro; it was postulated that these phenomena might also occur in vivo, constituting a previously unsuspected mechanism of immune tissue damage. The studies here presented confirm by intravital microscopy that PMN aggregation and leukoembolization in fact occur in live animals when C is activated or C5a is infused, and that these are accompanied by extravasation of plasma proteins in a pattern suggesting endothelial damage. It is concluded that altered microvascular behavior of PMNs is a possible pathogenetic mechanism in disease states associated with C activation.

Abstract: The ultrastructural cytopathologic and cytochemical effects of trimethyltin (TMT) neurotoxicity were delineated in hippocampal and pyriform neurons of acutely intoxicated adult rats. TMT produced neuronal necrosis that preferentially involved hippocampal formation pyriform cortex. The first subcellular alterations were multifocal collection of dense-cored vesicles and tubules and membrane-delimited vacuoles in the cytoplasm of the perikaryon and proximal dendrite. Ultrastructural cytochemical examination revealed that the vesicles and tubules had acid phosphatase activity analagous to Golgi-associated endoplasmic reticulum (GERL). Shortly after the appearance of the GERL-like vesicles and tubules, autophagic vacuoles and polymorphic dense bodies accumulated in the neuronal cytoplasm. Some dense bodies appeared to arise from the dense-cored tubules. Neuronal necrosis was characterized by increased electron density of the cytoplasm and large, electron-dense intranuclear masses. Alterations of mitochondria and other organelles were not observed in the early stages of cell injury. No light- or electron-microscopic alterations were found in liver or kidney. Comparable subcellular alterations were observed in adult and neonatal rats chronically intoxicated with TMT. A series of other trialkyl and tricyclic tins and dimethyltin did not produce similar pathologic findings. The GERL-like accumulations are unique in neuronal cytopathology. These findings suggests that GERL and autophagy play an important role in the pathogenesis of TMT-induced neuronal injury.

Abstract: The authors recently described a group of diabetic patients with severe congestive heart failure, hypertension, and minimal coronary artery disease, who had significant myocardial degeneration apparently secondary to the combined effects of high blood pressure and diabetes on the heart. To evaluate the effects of hypertension and diabetes mellitus more fully, the authors studied four groups of rats with either no disease, streptozotocin-induced diabetes mellitus, renovascular hypertension, or a combination of hypertension and diabetes. They employed semiquantitative light microscopy, which revealed significantly greater replacement fibrosis in the hypertensive-diabetic rats when compared with the other three groups. Interstitial fibrosis was increased in the hypertensive-diabetic animals, though it was just below the 5% level of significance when compared with the hypertensives. Further analysis, however, revealed that those hypertensive-diabetic animals with the greatest relative cardiac hypertrophy, as measured by the heart weight/body weight ratio, had significantly increased interstitial fibrosis. Surprisingly, diabetes mellitus alone produced no morphologic light-microscopic alterations; yet 8 weeks of combined hypertension and diabetes mellitus led to myocardial degeneration similar to the human disease. These changes do not appear to be secondary to abnormalities of intramyocardial muscular vessels. Measurement of 3 parameters of vascular disease revealed that hypertensive animals with less myocardial damage had greater vascular changes than the more severely affected hypertensive-diabetics. This study provides evidence that the combination of diabetes mellitus and hypertension produces significantly greater myocardial lesions than either disease alone. The similarity of the lesions with those observed in human patients suggests that the hypertensive-diabetic rat is a useful model for elucidating the pathogenesis of clinical myocardial disease in patients with hypertension and diabetes mellitus.

Abstract: Analyses of asbestos bodies from the general population have confirmed that these structures, like asbestos bodies from the lungs of asbestos workers, contain an asbestos core. In members of the general population this core is almost always an amphibole, whereas asbestos workers may have bodies formed on either amphibole or chrysotile. Most adults have a few bodies, and increasing numbers are seen in blue collar workers and others who handle small amounts of the fiber, with the highest levels being seen in asbestos workers. In men with minimal or extensive occupational exposure, asbestos bodies are formed on the commercial fibers, amosite and crocidolite, whereas women also form a significant number of bodies on the noncommercial fibers, anthophyllite and tremolite. These findings suggest that women may be exposed to specific asbestos-containing products, eg, cosmetic talc. The commercial fibers found in women and white collar men probably reflect atmospheric pollution with asbestos. At the highest levels of exposure, numbers of asbestos bodies correlate in a general way with the presence of asbestosis, although no precise value has been determined above which asbestosis is always found. In persons with much lower or environmental exposure, there does not appear to be any correlation between numbers of bodies and disease, in particular between numbers of bodies and carcinoma of the lung or gastrointestinal tract. The situation for mesothelioma is uncertain.

Abstract: The ultrastructure and cytochemistry of megakaryocytes from two patients with a familial gray platelet syndrome are described. Although the Golgi zones appeared normally developed, the megakaryocytes lacked alpha-granules. Catalase-containing particles were normal in number. In immature megakaryocytes, granules measuring from 0.05-0.1 mu and having an electron-dense core occurred in the Golgi area. These granules, which are considered as the precursors of alpha-granules in normal megakaryocytes, appeared unable to mature, and their number decreased with the megakaryocyte maturation. The presence of dense material in distended demarcation membranes and/or vacuoles suggested that their content was discharged. It is suggested that myelofibrosis present in the bone marrow from these two patients may be related to the possible excretion of a polypeptide growth factor normally contained in the alpha-granules. Megakaryocytes grown by the plasma clot procedure from blood precursors isolated from the two patients also did not exhibit alpha-granules, which were replaced by vacuoles. Our findings suggest that the lack of alpha-granules in gray platelets may be related to a defective megakaryocyte-committed cell, and evidence is presented which suggests that the precursors of alpha-granules are produced but that their contents are then lost.

Abstract: Mononuclear leukocytes isolated from the blood of rabbits, were labeled with 51Cr and returned to the animal intravenously. 51Cr-labeled monocytes disappeared from the blood with a half-life of 39.0 +/- 2.51 hours. Numerous acute inflammatory lesions were produced by the intradermal injection of Escherichia coli into the skin of the back of a rabbit. The animal was sacrificed after 1 hour, and the radioactivity in each lesion was determined. Monocyte accumulation was substantial by the time a lesion was 1 hour old. The maximum rate of accumulation occurred at 3--4 hours, and monocytes continued to enter the lesions at 25% of the maximal rate for at least 24 hours. Monocytes initially migrate into bacterial inflammatory sites simultaneously with neutrophils and histologically become the predominant cell type after 12 hours because they continue to migrate into these lesions long after neutrophils have stopped. The kinetics of monocyte migration is related to other aspects of inflammation.

Abstract: Metabolic products accumulate in ischemic myocardium secondary to reduced coronary flow, which prevents adequate washout of vascular spaces, and to reduced oxidative metabolism. The most notable products that accumulate are NADH, H+, lactate, CO2, long-chain acyl-CoA, and long-chain acyl carnitine. These products interfere with the production of ATP and the functioning of the myocardium. Glycolytic production of ATP is inhibited by accumulation of NADH, H+, and lactate. Mitochondrial and plasma membrane function may be altered by the acyl esters of CoA and carnitine. Mitochondrial membranes become structurally distorted and fragmented, and lipid-containing amorphous densities appear in the matrix. Structural alterations of mitochondria occur more frequently in hearts receiving high concentrations of fatty acids and correlate with high tissue levels of acyl esters of CoA and carnitine. Addition of acyl carnitine to mitochondria isolated from normal hearts results in nodulose-appearing cristae and fragmentation of mitochondrial membranes.

Abstract: Entactin is a sulfated glycoprotein in the extracellular basement membrane like matrix produced by M1536-B3 cells, a mouse endodermal line derived from an embryonal carcinoma. It has a molecular weight of 158,000 and is chemically and immunologically distinguishable from GP-2 (laminin) and fibronectin. Antibodies produced against entactin and GP-2 react with subepithelial and vascular basement membranes in rat lung, liver, spleen, and kidney and mouse placenta and kidney when examined by light microscopy. Both antibodies yield staining around the marginal sinus of the white pulp of the spleen. Antientactin reacts with basement membrane and mesangium in rat glomeruli, and anti-GP2 does not. Ultrastructurally, staining in kidneys is strongest at epithelial or endothelial cell membranes bordering basement membranes, with only moderate staining of the basement membrane proper. Intracellular staining is not present. The location of entactin suggests that it has a role in the interaction of cells with extracellular matrix, possibly in adhesion. Lack of intracellular staining suggests that the tissues studied are not actively producing entactin or GP-2 and that these substances may be fairly stable in adult organisms.

Abstract: Chronic passive congestion (CPC) and centrilobular necrosis (CLN) are well recognized pathologic changes, but their exact relationship to different forms of cardiac dysfunction is uncertain. We reviewed clinical data and hepatic, renal, and adrenal morphology related to cardiac dysfunction in 1000 autopsy subjects at The Johns Hopkins Hospital whose hearts had been studied after postmortem arteriography and fixation in distention. Fourteen pathologic variables, including body and organ size, and microscopic changes graded on a semiquantitative scale, and 18 clinical variables including congestive heart failure, shock, and cardiovascular disease, were analyzed statistically. Distinct patterns of cardiac dysfunction emerged for the two spectra of hepatic morphologic change. Among patients with variable CPC, but slight or absent CLN, the amount of CPC was predicted in a multivariate analysis by severity of right-sided congestive heart failure. CPC severity correlated with cardiac weight and chamber enlargement (P less than 0.001). Among patients with variable CLN, but slight or absent CPC, CLN was predicted by profound hypotension and by renal failure. In addition, CLN, but not CPC, was significantly correlated with renal acute tubular necrosis (P less than 0.001) and adrenal cortical medullary junction necrosis (P less than 0.05), two lesions associated with shock. Among all 1000 patients CPC and CLN were highly significantly correlated (P less than 0.001). The results show that hepatic CPC arises from conditions producing elevated systemic venous pressure but that CLN arises from reduced systemic arterial pressure; and the presence of one potentiates the development of the other.

Abstract: The role of extracellular Ca2+ ions in the killing of liver cells by CCl4 was studied in primary cultures of rat hepatocytes The dependence of in vitro cell killing on the metabolism of CCl4 was first examined in order to document the similarity between the action of CCl4 on cultured hepatocytes and the action of CCl4 on liver cells in the intact animal Cells prepared from male rats pretreated with phenobarbital were more sensitive to CCl4 than cells prepared from either male or female rats The killing of hepatocytes by CCl4 was prevented by addition of SKF 525A to the culture medium This protection was accompanied by evidence of decreased CCl4 metabolism as assessed by the extent of covalent binding of 14C-CCl4 metabolites to total cellular lipids and proteins, and by the extent of formation of conjugated dienes accompanying the peroxidation of phospholipids isolated from total cell lipids The extent of killing of the hepatocytes by CCl4 was dependent on the Ca2+ concentration in the tissue culture medium Total Ca2+ concentrations lower than 010 mM were not associated with any CCl4-induced cell death, and the number of dead cells increased with increasing Ca2+ from 03 to 36 mM This dependency on extracellular Ca2+ was not due to dependency of the extent of metabolism of CCl4 on Ca2+ The Ca2+ concentration in the medium had no effect on the extent of covalent binding of metabolites of CCl4 to lipids and to proteins and on the extent of peroxidation of phospholipids as shown by the formation of conjugated dienes In addition, hepatocytes incubated in low Ca2+ with CCl4 developed further evidence of cell injury, as indicated by the killing of these cells following the addition of high Ca2+ concentrations under conditions prohibiting any further metabolism of the CCl4 The results of this study indicate that it is the presence of extracellular Ca2+ that converts initially nonlethal cell injury into irreversible cell injury in CCl4-treated cells This action of Ca2+ most likely represents an influx into the cell across an injured permeability barrier at the plasma membrane, in accord with the accumulation of large quantities of Ca2+ in CCl4-intoxicated liver cells in the intact animal The relation between this alteration in Ca2+ homeostasis and the metabolism of CCl4 is discussed

Abstract: Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) is a potent inducer of systemic anaphylactoid reactions in animals. It was found to be similarly potent in contracting smooth muscle of guinea pig ileum and lung and in enhancing vascular permeability when injected subcutaneously into these animals. This factor, therefore, possesses in vitro and in vivo bioactions that resemble those of C3a and C5a anaphylatoxins. However, platelet-activating factor induces a slowly developing, sustained contractile wave in ileum that is not inhibited by an antihistaminic compound, pyrilamine, whereas C3a and C5a stimulate rapid transient contraction that is abrogated by the antihistamine. Furthermore, platelet-activating factor desensitized the ileum to restimulation by itself but not by C3a or C5a; conversely, C3a and C5a desensitized the ileum to themselves but not to platelet-activating factor. Thus, platelet-activating factor possesses a distinctive set of anaphylactic actions. It stimulates a slow wave of muscle contraction and can act independently of histamine release and receptors for the C3a and C5a anaphylatoxins.

Abstract: Prolonged arterial constriction can cause damage to the artery itself. The purpose of this study was to define the intimal changes. Two muscular arteries of the rat were studied by electron microscopy 15 minutes to 7 days after L-norepinephrine had been dripped over the vessels. Endothelial damage was caused by the tight folding of the internal elastic lamina, which mechanically squeezed the cells. As the artery relaxed, the endothelium showed gaps, patches of thinned cytoplasm, and many adhesions between cells on opposite sides of intimal folds. The adhesions involved whole cells of cytoplasmic bridges stretched across the intimal "valleys." They were present up to one day; later they seemed to snap and disappear without causing further cellular damage. A survey of the literature shows that such adhesions can also develop in collapsed arteries postmortem. They explain the endothelial "bridges" previously described by others as a normal intimal structure.

Abstract: The possible role of oxygen metabolic products in immune-complex--induced injury of rat lung and of dermal blood vessels has been probed with the use of two inhibitors, superoxide dismutase (SOD) and catalase. With the use of the reversed passive Arthus reaction in the skin, local administration of SOD, but not of catalase, blocked the early phase of the tissue injury, as quantitated by the leakage of homologous albumin. The early phases of immune-complex--induced injury of the lung were completely blocked by the parenteral (intraperitoneal) administration of SOD. Except at very high doses, SOD did not interfere with chemotactic-factor--induced release of lysosomal enzymes from rat neutrophils. These data suggest that oxygen metabolic products such as O(2-) may play an important role in the early phases of damage produced in rat alveolar walls and dermal vasculature by the deposition of immune complexes.

Abstract: A histochemical study was performed on light- and electron-microscopic level in a case of Fabry's disease. The patient underwent kidney transplantation for renal failure and died of heart failure 6 months later. Patient's tissues were studied at the light- and electron-microscopic levels with various embedding and staining techniques for lipids and carbohydrates. Two peroxidase-labeled lectins (from Ricinus communis and from Bandeiraea simplicifolia) known to have affinity for alpha- and beta-D-galactose, were strongly reactive with the storage material on frozen sections. The ultrahistochemical and extraction tests showed that the typical granules had a variable reactivity and morphologic characteristics in different cells, probably reflecting different composition. A small number of typical deposits were also observed in the transplanted kidney. This is the first reported case of recurrence of the storage disease in the allograft. Of interest was also the fact that the patient's blood inhibited normal alpha-galactosidase activity, suggesting a possible inhibitor-related mechanism in the pathogenesis of the recurrence.

Abstract: The ultrastructural organization of ruthenium red (RR) stainable material within small blood vessels located in the limbus of the rabbit eye was studied. Proteoglycans were identified in this material by digesting tissues with Streptomyces hyaluronidase, testicular hyaluronidase, chondroitinase ABC, or heparinase before ruthenium red staining. Neuraminidase digestion enabled separate identification of sialoglycoprotein. The luminal surface of endothelial cells demonstrates an RR-stained glycocalyx containing both sialoglycoprotein and proteoglycans, which are removed by testicular hyaluronidase and crude heparinase. The basal coat of endothelial cells and small granules (10-20 nm in diameter) located within the basal lamina stain with RR and are removed only by crude heparinase. The surface coat of smooth muscle cells and small granules (10-20 nm) within their basal laminas are also digested by crude heparinase. Large proteoglycan granules (20-50 nm), which are completely removed by testicular hyaluronidase and partially digested by Streptomyces hyaluronidase, are deposited between the connective tissue fibers of the media and adventitia. Other large granules that are attached to collagen fibers contain enzyme-resistant anionic materials. The surface coat of adventitial fibroblasts is removed only by crude heparinase. Thin filaments (3-5 nm in diameter) interconnect the cell coat material, basal lamina granules, and large connective tissue granules, to form a network of proteoglycans that traverses the intima, media, and adventitia. The highly ordered arrangement of proteoglycans in the microvascular wall suggests that these macromolecules play several roles in microvascular function.

Abstract: Freeze-fracture studies of caveolar density and distribution were carried out in skeletal muscle plasma membrane from 6 patients with Duchenne muscular dystrophy (DMD), 5 patients with facioscapulohumeral dystrophy (FSH), 5 patients with myotonic dystrophy (MyD) and 5 normal control subjects. The results showed a significant increase in the number of caveolae and a decrease in size in a population of muscle plasma membranes from patients with DMD. No significant changes in the caveolae were observed in muscle plasma membranes from patients with FSH and MyD.

Abstract: Intracellular myoglobin represents an excellent marker for specific characterization of normal (adult and fetal) and malignant skeletal muscle cells in paraffin sections. With an immunoperoxidase indirect sandwich technique for detection of intracellular myoglobin, positive staining was observed in 13 of 17 rhabdomyosarcoma specimens including 5 of 7 of the alveolar type, 5 of 5 of the embryonal type, and 3 of 5 of the pleomorphic type. Initial fixation in Zenker's-acetic acid solution gave optimal staining, but satisfactory results were obtained with fixation in formalin, Bouin's, and B5 solutions. Other types of sarcomas (13 cases) and other types of tumors (24 cases) that sometimes mimic rhabdomyosarcoma on histologic examination gave negative results. The immunoperoxidase method affords a sensitive and specific method for identifying rhabdomyoblasts in tissue on the basis of intracellular myoglobin and is of use in distinguishing rhabdomyosarcomas from other sarcomas and from malignant tumors of other types.

Abstract: The molecular nature of neurofibrillary tangles of senile dementia of the Alzheimer type (SDAT) was studied by immunoperoxidase and immunofluorescence techniques. Five antiserums, including anti-humanbrain-2-cycle-purified-microtubule-fractions (2 x MT), anti-calf-brain-2 x MT, anti-sea-urchin-egg-tubulin, antibeef-brain-tubulin, and anti-human-brain-neurofilament(NF)-210-kilodalton(kd)-protein were tested for their binding to neurofibrillary tangles. The antihuman-2 x MT serum stained structures resembling neurofibrillary tangles, neurites of neuritic plaques, and microglialike cells in SDAT brains, but no such staining pattern was detected in normal brain sections. In neurons isolated from SDAT brains, about 40% of the tangles were labeled by the anti-human-2xMT serum with an identical pattern. Other antiserums tested did not preferentially bind tanglelike structures in tissue sections and bound to less than 5% of the tangles in isolated neurons. These results suggest that the antigenic sites of tubulin and NF proteins are not shared by neurofibrillary tangles. Different from the calf preparation, the human-2 x MT fractions contained a prominent protein band that was identical to ferritin in molecular weight and cross-reacted with anti-human-2 x MT and anti-human-ferritin serums. However, antiserums to this ferritinlike protein, or anti-ferritin, did not stain neurofibrillary tangles. Although neither the calf 2 x MT nor two other human MT fractions failed to elicit an antiserum that stained tangles, these fractions were able to remove the antihuman-2 x MT serum activity that binds to tangles. The data suggest that the protein (or proteins) that makes up neurofibrillary tangles of SDAT is present in various quantities in microtubule fractions of normal brain.

Abstract: The purpose of this study was to compare the group-cell migration characteristics of endothelial cells (ECs) and smooth muscle cells (SMCs) derived from the same source, the porcine thoracic aorta, as they moved into an experimental in vitro wound. The authors characterized migration by measuring two aspects of the migrating cells: the number of free cells in the wound and the distance of migration of the sheet of cells at the wound edge. The quantitative data showed that ECs migrated into the wound as a sheet of cells, while SMCs migrated as free single cells. In addition, since irradiated cells have been used to study cell migration and since the irradiated cells do undergo some shape changes, the distribution of the cytoskeletal microfilament fibres was compared in migrating irradiated and nonirradiated cells in order to see whether this feature of cell migration was different. Irradiated and nonirradiated migrating ECs showed a strikingly different pattern in the orientation of microfilament bundles when studied by immunofluorescence microscopy with antiserums to myosin and tropomyosin.

Abstract: Results of previous experiments in this laboratory indicate that lipids, especially cholesterol and cholesteryl ester, preferentially accumulate in re-endothelialized, as compared with de-endothelialized, areas of aorta (Am J Pathol 1980, 99:81-104). In the experiments reported here, the hypothesis that this lipid accumulation results from alterations in arterial wall metabolism induced by injury and modified by endothelium was tested. Activities of the two cholesterol-ester-metabolizing enzymes acyl CoA: cholesterol acyltransferase and acid cholesteryl esterase were assayed in uninjured aortas and in de-endothelialized and re-endothelialized areas of balloon-catheter-injured aortas from normocholesterolemic and hypercholesterolemic rabbits. Activities of marker enzymes for major cell organelles were also assayed. Our results indicate that acyl CoA: cholesterol acyltransferase activity was similarly increased in re-endothelialized and de-endothelialized areas of injured aortas. Activity of acid cholesteryl esterase was also increased; however, it was significantly less in re-endothelialized as compared with de-endothelialized areas. Activities of several marker enzymes were changed in injured aortas, particularly in de-endothelialized as compared with re-endothelialized areas. These findings suggest that 1) injury predisposes to general metabolic changes in the aorta that are modified by endothelium and 2) increased cholesteryl ester accumulation in re-endothelialized aortas occurs at least in part from increased synthesis and decreased hydrolysis.

Abstract: Urinary bladder damage caused by surgical incision, freeze-ulceration, or formalin instillation in male Fischer 344 rats was studied by light and scanning electron microscopy. The first two methods resulted in focal ulceration of the urinary bladder; the last induced diffuse mucosal damage. With each method, the damage was followed by regenerative hyperplasia and repair, the bladder mucosa returning to normal in 3-4 weeks. Epithelial cells in the hyperplastic areas had ropy microridges and uniform short microvilli on their luminal surfaces as observed by scanning electron microscopy. When the hyperplasia was marked, with nodular and papillary formation, occasional epithelial cells had pleomorphic microvilli on their surfaces. Rats treated either by surgical incision or freeze-ulceration had normal bladders after a 2-year observation period. Combined with results from previous experiments, pleomorphic microvilli are not a marker of neoplasia or irreversibility but appear with marked or prolonged mucosal proliferation even if reversible.

Abstract: Inoculation of dogs with Trypanosoma brucei produced an acute fetal disease similar to that seen following natural infection. The disease was characterised by high levels of parasitaemia, moderately severe anemia, and marked changes in the lymphoid system. Extravascular invasion by large numbers of trypanosomes was widespread throughout the body and was accompanied by severe tissue damage. Tissue invasion by trypanosomes was associated with marked cellular infiltration involving lymphoid cells and plasma cells followed by macrophages and polymorphonuclear leukocytes. Associated with these reactions, severe cellular degeneration and focal necrosis occurred. While these changes were widespread and were found in the majority of tissues examined, consistently severe lesions were found in the heart, eyes and central nervous system. In many organs, lymphatic vessels were distended with fluid, trypanosomes, and a cell population similar to that in the surrounding tissue; fibrin deposition and thrombus formation was sometimes observed within the lymphatic lumens. Thrombosis was also found in the blood vessels of the pampiniform plexus, the venous plexus of the ovary, and branches of the renal vein. A severe necrotizing vasculitis affecting only the coronary vessels was a prominent feature in some animals.

Abstract: Suckling Swiss mice were injected daily for 8 days with either electrophoretically pure (EP) mouse interferon (s.a. 4.7 x 10(8) units/mg protein), major impurities obtained in the course of purification, or partially purified mouse interferon (s.a. 1.3 x 10(7) units/mg protein). Only EP or partially purified interferon inhibited growth, induced liver and kidney lesions, and killed mice. The authors conclude that interferon itself is responsible for these effects.

Abstract: The development of coronary and aortic atherosclerosis was determined after balloon catheter injury of coronary arteries and administration of an atherogenic diet in normal pigs and pigs that were homozygous and heterozygous for von Willebrand's disease. Coronary atherosclerosis developed to a similar degree in all three phenotypic groups. The mean intimal thickness at the site of maximal thickness in ballooned vessels was .51 mm in the normal pigs, .67 mm in carrier pigs, and .55 mm in bleeder pigs. The intimal thickness of non-ballooned vessels was .28 mm in normal pigs, .28 mm in carrier pigs, and .35 mm in bleeder pigs. Fibrous lesions of atherosclerosis covered an average of 3.88% of the aorta in normal pigs, 2.83% in carrier pigs, and 2.37% in bleeder pigs. The difference between the aortic lesions of normal animals and bleeders was significant (P less than .05). Absence of von Willebrand factor was associated with limited resistance to atherosclerosis in the aortas of experimental pigs but did not affect the development of atherosclerosis in either ballooned or nonballooned coronary arteries. These findings suggest, first, that von Willebrand factor function is not essential to the development of the atherosclerotic lesion in this model and, second, that the role of the von Willebrand factor in the development of atherosclerosis is complicated and appears to involve interaction with variables not yet defined.

Abstract: The morphologic and biochemical characteristics of human surgical biopsy specimens taken from 17 patients with anaplastic human gliomas and of athymic mouse-grown tumors derived from them were examined. Fourteen were categorized as glioblastoma multiforme, one as an anaplastic astrocytoma, one as a recurrent glioblastoma multiforme, and one as a gliosarcoma. Fifteen of 17 tumors stained positively immunohistochemically for glial fibrillary acidic protein (GFAP), a glial-specific marker. When portions of the 17 surgical biopsy specimens were injected into the flank subcutaneous space of athymic mice, 16 produced tumors; different portions of a single biopsy specimen were used to establish three separate tumor lines; in toto, 18 tumor lines were established. Mouse-borne tumors contained various proportions of fibrillary and protoplasmic astrocytes, gemistocytes, small anaplastic cells, and multinucleated giant cells. Some were more homogeneous than the human tumors from which they were derived, while others contained a mixed population similar to that of the original biopsy specimen. Of these initial 18 tumors, 16 were stained for GFAP and 14 contained from fewer than 5% to almost 100% GFAP-expressing cells. Ten of the tumor lines were studied in serial passage, several demonstrating increased cellularity with increased passage. GFAP expression was followed through serial passage, and 7 of 10 tumor lines continued to express it, often in reduced amounts, and 2 of 10 ceased expression, one (the gliosarcoma) never having expressed it. These data demonstrate that while athymic mouse-borne human anaplastic gliomas retained some features of the human tumors from which they were derived, they varied from one another morphologically. These mouse-borne tumors also continued to evolve, often changing their levels of GFAP and demonstrating increased cellularity with passage.

Abstract: Bonnet monkeys (Macaca radiata) were exposed to 0.0, 0.5, or 0.8 ppm ozone for 7, 28, or 90 consecutive days, 8 hours per day. The pulmonary response was evaluated by means of pulmonary function testing, light microscopy, scanning electron microscopy, transmission microscopy, autoradiography, and morphometry. Pulmonary function values obtained before exposure did not statistically differ from values obtained after exposure. A general trend of increased quasistatic compliance of the lung was observed in both groups of exposed monkeys. Morphologic changes were principally characterized as low-grade chronic respiratory bronchiolitis. Major features were intraluminal accumulations of macrophages and hypertrophy and hyperplasia of cuboidal bronchiolar epithelial cells. The intensity of this inflammatory response was determined by counting the number of intraluminal inflammatory cells per millimeter of respiratory bronchiolar surface. The magnitude of inflammation was greatest at the 0.8 ppm ozone concentration at each exposure period; however, the number of inflammatory cells present at 90 days was less than one half that observed at 7 days, in spite of persistent ozone insult. Tritiated thymidine labeling and counts of respiratory bronchiolar epithelium demonstrated up to a 37-fold increase in labeling index at 7 days but only a sevenfold increase at 90 days. Differential cell counts demonstrated an increase in the proportion of cuboidal bronchiolar cells constituting the respiratory bronchiolar epithelium. In control monkeys, 60% of the epithelial cells were cuboidal bronchiolar cells. At 90 days of exposure, more than 90% of the respiratory bronchiolar cells were cuboidal in appearance. The cuboidal bronchiolar cell in control monkeys does not appear secretory, but membrane-bound electron-dense secretory granules are present in this cell type from exposed monkeys. Epithelial hyperplasia (increased number of cells per millimeter of airway length) persisted through 90 days of exposure at a level slightly above that present at 7 days.