An analysis of hepatic venocclusive disease and centrilobular hepatic degeneration following bone marrow transplantation

In order to assess the prevalence of venocclusive disease in autopsied recipients of bone marrow transplantation, we reviewed coded liver histology from 204 consecutive autopsied recipients transplanted for leukemia (142), other malignancies (5), or aplastic anemia (57). Twenty-seven patients with leukemia, 2 with carcinoma, and 3 with aplasia had venocclusive disease and survived 2-86 days post-transplant. Early lesions showed subintimal edema and hemorrhage within small central venules and centrilobular congestion with hepatocyte degeneration. Later lesions showed subtotal to complete fibrous obliteration of the central venule lumina and centrilobular sinusoidal fibrosis. Thirteen patients had a subclinical course, and 19 were symptomatic. Venocclusive disease was life-threatening or lethal in 13. Typical symptoms developed 1-3 wk post-transplant and consisted of sudden weight gain, hepatic enlargement, ascites, high bilirubin, and encephalopathy. Statistical analyses showed a significantly higher prevalence of venocclusive disease associated with transplantation for leukemia (P = 0.014), pretransplant conditioning with more rigorous chemoradiotherapy regimens (P < 0.001) and three- to fourfold increase of venocclusive disease in patients whose conditioning included dimethyl busulfan (P < 0.005). Abnormal liver tests before transplant were also more prevalent among patients with venocclusive disease. No factors predicted the clinical outcome of established venocclusive disease. Venocclusive disease showed no association with hepatic graft-versus-host disease even among prolonged cases with severe periportal hepatitis and cholestasis. Other centrilobular lesions (hepatocyte degeneration, sinusoidal fibrosis, and phlebosclerosis) were identified in 23 patients. These non-specific changes may occur with viral hepatitis, graft-versus-host disease or chemoradiotherapy effects.

Morphological changes in paracortical high endothelial venules to single and repeated application of oxazolone to mouse skin

Morphological changes in paracortical high endothelial venules (HEV) have been studied after single and repeated applications of oxazolone to mouse skin. The primary response was characterized by a rapid and marked vascular dilatation, by marked increase in the cross sectional area of the vessel wall and in the size of the individual endothelial cells, as well as increased accumulation of lymphocytes in HEV walls. These changes regressed (in the more long lasting response). The transitory structural alterations may be related to increase of blood flow, increased flow of cells from the thymus to the stimulated lymph nodes as well as increased transport capacity of endothelial cells based on augmentation of their surface area. These features are closely related to other cellular events such as a prominent blastoid reaction in the paracortex as well as an associated cellular depletion of the thymus.

Pulmonary calcification and elastic tissue damage in pseudoxanthoma elasticum

A case of pseudoxanthoma elasticum with extensive calcification and elastic tissue damage in the lung is described. This patient had classical skin changes, peripheral arterial calcification, and heart block, but no retinal changes. Hypercalcemia was excluded. Pulmonary involvement is in keeping with the concept of the basic abnormality being in the elastic fibres, and such involvement should be considered as a cause of respiratory symptoms in patients with this condition.

[Hypothalamic characteristics in sudden human cardiac death]

The hypothalamus was examined in cases of sudden heart death in 50 persons of both sexes whose ages ranged from 25 to 55. The microscopic and biochemical findings were compared with those in cases of heart death which had not occurred suddenly in patients with myocardial infarction of different duration (50 cases). It is shown that in sudden heart death diffuse edema of the white matter and dystonic changes in the microcirculation vessels develop in the hypothalamus. Biochemical examination discloses in the tissue of the hypothalamus in such cases a sharp decrease in the content of noradrenalin and the precursor of catecholamine synthesis DOPA and a marked increase in the level of adrenalin. It is assumed that there is a causative connection between vascular dystonia and the decrease in the noradrenalin level. An increase in the adrenalin content may be conducive to the intensification of cerebral hydrophilism.

The microvasculature is the critical target of the immune response in vascularized skin allograft rejection

Vascularized first set human skin allografts were rejected largely by a process of extensive and progressive microvascular damage leading to ischemia and infarction. Microvascular injury was associated with a cellular immune response. However, vessel damage was at least in part immunologically nonspecific because vessels of the graft bed (host tissue) were damaged as well as those of the graft itself. We conclude that the microvascular endothelium is the critical target of the immune response in vacularized skin allografts in man, and that this sequence of events--primary vascular damage followed by ischemic infarction--may have significance in a variety of experimental and clinical settings.

Importance of terminal hepatic venule thickening

Thickening around the terminal hepatic venule (THV) in alcoholics has been implicated as a marker for fibrosis and cirrhosis. To test this hypothesis, we evaluated 107 liver biopsy specimens from patients with normal liver histologic features (12), fatty livers (30), mild alcoholic hepatitis (15), and florid alcoholic hepatitis (29). Twenty-one follow-up liver biopsy specimens from patients with fatty liver and alcoholic hapatitis were also available for this study. Two observers (S.M.N., V.H.N.) graded 18 histologic features on a scale of 0 to 3. There was no significant difference in the prevalence of THV thickening in normal biopsy specimens and in various forms for alcoholic liver injury. There was also no correlation between the degree of THV thickening and steatosis, necrosis, or inflammation. Thickening of the THV was most common in the presence of lobular and subsinusoidal fibrosis. Cirrhosis developed in nine of ten alcoholic patients who had subsinusoidal and lobular fibrosis. These findings illustrate that the marker for progressive fibrosis and development of cirrhosis is lobular and subsinusoidal fibrosis and not the isolated thickening of the THV.

[Angio-immunoblastic lymphadenopathy and local immuno-reactions of the lymph nodes (author's transl)]

Report on histological findings in lymph nodes, spleen, bone marrow, liver, lungs and kidneys in angio-immunoblastic lymphadenopathy and comparison with localized immuno-reactions of lymph nodes. Beside principal similarities in cellular and vascular proliferation differences may be noticed in the degree of preservation of the lymphonodular architecture, in the degree of proliferation of "immune cells" and postcapillary venules, and in the height of their endothelium. While for local immuno-reactions of the lymph nodes a regulated course may be supposed, the reaction in angio-immunoblastic lymphadenopathy is interpreted as an expression of dysregulation--presumably concerning to the function of T-cells--which occasionally may lead to a transformation into malignant lymphoma. Possible initial stages of this transformation are demonstrated by means of an own observation.

Effects of aging on the structural and permeability characteristics of cerebrovasculature in normotensive and hypertensive strains of rats

This study demonstrates that markedly different patterns of age-related changes in blood pressure and body weight occur among normotensive Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR). In addition, a variety of age-related structural alterations occurred in the walls of arterioles, capillaries, and venules of the frontal cortex. These changes include: (1) an increase in the thickness of the vascular wall by deposits of collagen and basal lamina which, in some cases, extended into the surrounding neuropil; (2) the presence of a flocculent material in the adventitia of intracerebral arterioles; (3) vesicular inclusions in perivascular macrophages, pericytes and smooth muscle cells which were labelled with i.v. administered horseradish peroxidase (HRP); (4) fragmentation of smooth muscle cells; and (5) accumulation of lipofuscin-like pigments in perivascular glial processes. The hypertensive rats exhibited these changes, but they were more advanced and more widely distributed throughout the cerebral cortex. The aged hypertensive rats occasionally had large bundles of 10 nm diameter, intermediate filaments in the endothelial cells. Whereas no change in blood-brain barrier permeability to HRP was observed in the aged normotensive rats, all age groups of the hypertensive rats exhibited increased permeability to HRP in the initial segment of penetrating arterioles in laminae I and II of the cerebral cortex.

The importance of nonrenal involvement in hemolytic-uremic syndrome

Fifteen children with the clinical manifestations of hemolytic-uremic syndrome are reported. Prompt recognition of the syndrome and effective therapy for acute renal failure including early dialysis were instituted in each case. Analysis of the clinical course and histopathologic features in these patients indicated that early dialysis and effective management of acute renal failure may unmask evidence of nonrenal involvement; microthrombi may be found in a wide distribution of organs, including the brain and myocardium; and extent and severity of nonrenal involvement become an important determinant of ultimate prognosis.

Brain aging in normotensive and hypertensive strains of rats. III. A quantitative study of cerebrovasculature

Quantitative histological techniques were used to evaluate age-related alterations in the vascularity and thickness of the cerebral cortex in normotensive and hypertensive strains of rats. In both strains, aging was accompanied by a statistically significant increase in mean minimal luminal diameter (MMLD) of capillaries in all cortical laminae. While the overall depth of the cerebral cortex was significantly decreased in aged rats of both strains, the total number of capillaries in a strip of cortex extending from the pia mater to the underlying white matter did not change between 3 months and 23-24 months. The greatest vascularity was seen in the field occupying 41-60% of the depth below the pial surface. Few differences in the laminar variations in capillary density were observed. The number and MMLD of venules were increased in aged WKY, but the aged hypertensive rats exhibited a decrease in number and MMLD of venules. No significant changes in either the number or MMLD of arterioles was observed in aged and/or hypertensive rats. The total brain weight of the hypertensive rats was significantly less than that of normotensive rats at 3 and 12 months of age but no difference was observed between the aged groups. Hypertensive rats demonstrated a significantly decreased relative brain weight (brain weight per 100 g body weight) in all age groups.

Vascular ectasias of the right colon in the elderly: a distinct pathologic entity

Vascular ectasias (angiodysplasias, arteriovenous malformations) of the cecum and ascending colon are a frequent cause of lower intestinal bleeding in the elderly that has been overlooked by clinicians and pathologists. Their nature and etiology have been poorly understood until recently. This article reviews the previous literature and presents a complete and detailed description of these lesions based on the examination of 87 areas showing vascular ectasia from 26 colons. Their morphology spans a spectrum from small focal early lesions to multiple large late lesions. The early lesions are characterized by markedly dilated, large, tortuous submucosal veins with minimal dilatation of their tributaries in the mucosa. The late lesions showed further dilatation of submucosal veins and venules and extensive replacement of the overlying mucosa by racemose collections of dilated and thin walled venules and capillaries, three of which demonstrated rupture into the colonic lumen. The pathology of these lesions is considered to be specific enough to establish vascular ectasias of the colon as a distinct entity.

Cutaneous necrotizing venulitis in patients with cystic fibrosis

Palpable purpura was noted to occur late in the course of some patients with cystic fibrosis. Skin biopsy specimens showed necrotizing venulitis characterized by a perivenular infiltrate composed of neutrophilic leukocytes, fibrin, hypogranulated mast cells, and endothelial cell necrosis. Circulating immune complexes were detected. Recurrent pulmonary infections and the chronic administration of therapeutic agents provide sources of potential antigens.

[State of the microcirculatory bed of the mesentery in experimental dehydration]

The results of a complex functional-morphological analysis on the state of the mesentric microcirculatory bed have demonstrated a peculiar dynamics in increasing changes of its blood and lymphatic segments. Their degree depends on the stage of dehydration. On the 3d day, the changes revealed are not great and are of redistributive character. On the 6th day dehydration aquires the maximal intensity of changes in vessels and hemodynamics. By the 10th day, maximal level of vascular, intravascular and hemodynamic disorders is evident. Comparing these data and the results of investigations on intracellular and extracellular ion contents, it is possible to suggest a definite staged water elimination from the main depots of the organism. The reserves of extracellular water section are the first to be mobilized at the expense of its interstitial and transcellular links. On the 6th day of the experiment maximal intensity of blood and lymphatic dehydration is noted. Final stages of dehydration are characterized by a pronounced cellular dehydration.

Disc vascularity in Down's syndrome

Ocular fundus photographs of 100 eyes were obtained from an institutionalized population of patients with Down's Syndrome (66 males, 34 females). The vascularity of the optic nerve head was assessed in each photograph by counting the number of arterioles, venules, and fine vessels crossing the disc margin. The results of this analysis were compared to similar data obtained from 100 ocular fundus photographs of normal patients and show that there are more large vessels crossing the disc margin in those with Down's Syndrome.

The inflammatory response to endotoxin

A typical inflammatory response resulted from the intravenous injection of endotoxin (E. coli) into living rabbits. Each rabbit was studied at three levels: the microvasculature and supporting tissue in the ear chamber was observed microscopically (up to X200) before, during, and at regular intervals following the injection of endotoxin; leucocyte and platelet counts were made periodically throughout each experiment; and tissue samples for histological study were obtained from each rabbit prior to death. The animal was anaesthetised before histological samples were secured. Within minutes after the intravenous injection of endotoxin, leucocytes were observed sticking to the endothelial cells lining the venules and the arterioles. Emboli appeared in the microcirculation within 10 min. Swelling of the microvascular endothelial cells was evident at 1 hr; oedema and extravasation of the cellular elements followed. The rectal temperature and leucocyte and platelet counts all fell within 10 min. of endotoxin. Histological examination of tissue from the ear chamber and visceral organs showed inflammatory changes. Congestion of the microvasculature, swelling of the endothelial cells, and margination and migration of neutrophils were common histological features in all organs. The earliest cells affected appeared to be the leukocyte and platelet.

Morphological observations on the vasculitis in the mucocutaneous lymph node syndrome. A skin biopsy study of 27 patients

Twenty-seven skin biopsies were obtained from the exanthemata of patients in the acute stage of the mucocutaneous lymph node syndrome (MCLS). The three vascular systems of different caliber size--the intrapapillary capillary loops (ICL), the superficial arteriolar or venular plexus (SAP, SVP) and the small subcutaneous vessels--were examined to investigate the characteristics of the vasculitis in MCLS and differentiate it from infantile polyarteritis nodosa (IPN). Significant papillary edema and dilatation of ICL, SAP and SVP were observed on the 4th day after the onset of the illness, and then gradually decreased. In the subcutaneous regions, vasculitis began with endothelial necrosis, and subendothelial edema and degenerative changes in the muscle cells followed. These changes in the small subcutaneous vessels were observed for a longer period than in the ICL, SAP and SVP. Moderate mononuclear cell infiltrations were observed. Both arteries and veins were affected.

Cutaneous necrotizing venulitis: a sequential analysis of the morphological alterations occurring after mast cell degranulation in a patient with a unique syndrome

An unusual patient, with dermal nodules, flexion contractures of the fingers and toes, cold-induced urticaria, dermographism and serum hypocomplementaemia, had necrotizing cutaneous venulitis underlying the spontaneous lesions. Since necrotizing cutaneous venulitis could be experimentally induced by the physical stimuli of cold or trauma, the time-course of histopathological events was documented in the skin of this patient. The histopathological alterations were studied in 1 micron thick, Epon-embedded skin biopsy specimens over an interval of 6 days. The early massive degranulation of the mast cells was followed by the sequential infiltration of neutrophilic, eosinophilic and basophilic polymorphonuclear leucocytes, by the development of venular endothelial cell necrosis and by the deposition of fibrin. The persistent serum hypocomplementaemia involved the classic activating and amplification pathways. It seems possible that the unusual combination of pathobiological processes involving the mast cells and the complement system in this patient has created a unique syndrome, in which venules are damaged and the sheaths of the extensor tendons of the hands and feet become affected in time.

Early vascular changes in the spinal grey matter following impact injury

The ultrastructural changes of the microvasculature in the spinal grey matter were studied after impact injuries of varying severity in cats. Survival times ranged from 3 min to 6 h after injuries. The main vessels affected were capillaries and postcapillary venules. Perivascular haemorrhage and protein extravasation were present immediately after impact. Astrocytic foot processes could be swollen or shrunken and of increased electron density. The extra cellular space (ECS) was often distended with proteinaceous material. Some vessels showed an apparent increase in vesicles and small dense inclusions were seen in pericytes. By 20--30 min after impact, a number of vessels at greater impact energies showed degenerative changes in organelles and endothelial gaps. The lumina of these vessels often contained plasma, platelets, red cells and occasional neutrophils. Similar changes were seen between 3 and 6 h and at this stage neutrophils and some monocytes were present in the perivascular spaces and neuropil. Endothelial balloons and pericytic dense inclusions were also seen. It is suggested that initial events are mechanical, perhaps due to a rapid displacement of blood in venules followed by arterial hypertension (which commonly accompanies spinal cord impacts). Although initially many lumena are patent by 30 min there is a difference between the lesser and greater severities of impact.

Origin and localization of Evans blue extravasations in acutely-induced hypertension in cats

An intravital-microscopic study on cat pial vessels for the localization of Evans blue extravasation during acute hypertension was performed. The onset of extravasation was seen 10 sec to 2 min after the beginning of hypertension. The localization of initial extravasation turned out to be little venules, not arterioles. Venular congestion by an overload of venous outflow seemed to be the origin of extravasation.

Relationship between lymphocyte emigration and vascular endothelium in chronic inflammation

Small blood vessels within areas of chronic inflammation which contain large numbers of lymphocytes develop unusually thick walls. Combined histological and electron microscope study shows that the thickening is due to hypertrophy of endothelial cells which come to resemble the endothelium of post-capillary venules in lymphoid tissue. Vessels of this type have been found in experimental granulomas induced by injection of Freund's adjuvant or killed tubercle bacilli and in human biopsy material from cases of rheumatoid arthritis and Hashimoto's disease of the thyroid. Comparison with the developing Peyer's patch in young rats shows that the unusual vessels in granulomas are very similar in endothelial cell size, pattern of distribution, extent of lymphocyte migration and degree of carbon leakage to post-capillary venules of the immature Peyer's patch. Study of the time at which lymphocytes appear in large numbers within the granuloma or developing Peyer's patch and the time at which thickened vessels are first seen suggest tha the endothelial changes are a consequence and not a cause of lymphocyte emigration. The stimulus to endothelial hyperthrophy appears to be massive sustained migration of lymphocytes, but the functional significance of this change in vascular structure is not clear.

Post-capillary venules in the lymphatic tissues of mice bearing experimental neoplasia

The lymph nodes, thymus and Peyer's patches of DBA/2 mice bearing an experimental tumor, mastocytoma, were assessed histologically with special reference to the structure of the post-capillary venules. For each of the lymphoid organ studied, the post-capillary venule score (PCV-S) was determined on the three grades (grades 1, 2 and 3) of the venules classified according to the height of the endothelial cells. The highest scores were obtained in the lymph nodes and Peyer's patches of the control animals. The scores in these lymphoid organs of the tumor-bearing mice were statistically highly significantly lower than in the control series. The lowest scores, however, were obtained in the nodes and patches of mice bearing mastocytoma after the previous treatment with anti-theta-globulin. The scores in the thymuses did not deviate from each other in the three series of mice studied. The findings of the present work support the concept that the structural state of the post-capillary venules in the lymph nodes and Peyer's patches is an important regulator of the T-lymphocyte recirculation in these organs. On the other hand, the venules of the thymus seem to be unrelated both structurally and functionally to the post-capillary venules of the nodes and Peyer's patches, and a new name of "junctional venules" has been proposed for these low endothelium walled venules of the thymus.

Ultrastructural basis of the vasculopathy in and around brain tuberculomas. Possible significance of altered basement membrane

The fine structure of small blood vessels in and around ten brain tuberculomas was examined. In the peripheral reactive zone of the tuberculomas, examination of 1-mu-thick survey sections established the chronic inflammatory process and the vasculitis characterized by infiltration of the vasomurium (vessel wall) by large and small mononuclear cells. This reaction was typical of chronic epithelioid cell granuloma. Electron microscopic examination of the reactive zone confirmed the vascular proliferation and vasculitis, the venule being the most frequently involved type of blood vessel. It showed the infiltrating cells to lie amidst osmiophilic, concentrically proliferated basement membrane laminae, which formed the greater part of the thickened vessel wall, generally surrounding the endothelial cells directly, the pericytes having disappeared. This appearance, together with the results of Gomori's reticulin stain on paraffin sections, suggested that the altered basement membrane material was reticulin. The possibility is discussed that the altered basement membrane material could be antigenic and that it might be responsible for perpetuating the necrotic vascular and perivascular reaction in tuberculous meningitis and tuberculomas. The above change in the basement membrane was not encountered in the blood vessels of the surrounding edematous brain. The endothelial cells and tight junctions were relatively well-preserved. Intact arterioles could be recognized even in severely edematous brain tissue. At both sites the fine structure of the blood vessels was typical of that expected in the central nervous system. Fenestrated vessels were not seen. The perivascular astrocytic end-feet were destroyed in the reactive zone and either distended or ruptured in the overtly edematous brain tissue also. In the central caseous part of the tuberculoma, there were few blood vessels, and they were in a state of advanced necrosis, but ghost outlines of proliferated basement membrane could be seen.

Morphological changes in lymphatic vessels in pulpal inflammation

Noncarious, carious, and restored human teeth obtained from individuals 20 to 65 years of age were used to study the differences in lymphatic drainage between healthy and inflamed pulps. In carious teeth, the lymphatic vessels located within and/or surrounding the inflammatory lesion were distended, a situation not demonstrable in pulps of noncarious and restored teeth.

Quantitative changes in mast cells and microvascular pattern associated with dietary gastric ulceration in rats

The regional distribution of mast cells and the microvascular pattern in the stomach of Wistar rats fed on an ulcerogenic diet were compared with those of control animals. Mounts of the distended stomach were made and stained for blood vessels and mast cells in the subserosal layer. Measurements made under dark ground illumination in 12 operationally defined regions of the serosa demonstrated that the stomach wall in the region around the oesophagus is more richly vascularised and possesses a greater number of mast cells (60 cells per mm2) than other regions. Changes in the mast cells and microvasculature were observed in rats fed an ulcerogenic diet, notably in the zone around the oesophagus, where more than 30% mast cells were degranulated and the mean vascular diameter increased by 26%. The severity of the vascular changes correlated with the location of the ulcers of which 50% were in the zone surrounding the oesophagus.