Takehiro Mitsuhashi

Experimental pulmonary fibrosis induced by trisodium citrate and acid-citrate-dextrose

A single intrapulmonary injection of 3.8% trisodium citrate and acid-citrate-dextrose (ACD) into rabbits results in extensive degeneration and necrosis of alveolar pneumocytes, including the type II pneumocyte, and of bronchiolar or bronchial epithelial cells. Subsequently, the alveoli and alveolar ducts collapse, and the septa and ductal walls adhere to each other, accompanied by the proliferation of interstitial fibroblasts. These fibroblasts produce fibrous connective tissue which is followed by pulmonary fibrosis in 1 week. Epithelial regeneration, especially that resulting from the proliferation of immature type II pneumocytes, occurs around the periphery of the fibrous lesions. The synthesis and release of large amounts of surfactant materials by the proliferated type II pneumocytes may induce the surfactant materials to reopen the air spaces of the collapsed and adhesive alveoli. By 4 weeks those fibrous areas in the pathological lungs become smaller and/or appear normal. These results suggest that this is a useful experimental animal model for pulmonary fibrosis, and that epithelial cells, especially type II pneumocytes, are associated with both the induction of and the recovery from the disorder; in the early stage, interference by reepithelization resulting from type II pneumocyte proliferation may elicit the proliferation of fibroblasts, and in later stages, reepithelization and surfactant synthesis by newly proliferated type II pneumocytes may permit the reopening of collapsed and adhesive air spaces.

Malignant T-cell lymphoma of the pancreas.

A case of malignant T-cell lymphoma of the pancreas is presented. Previously reported histological data confirming this disease are reviewed to elucidate features that may suggest this disease and how to differentiate between T- and B-cell lymphoma of the pancreas.

Intrasellar cavernous angioma in neurofibromatosis

A case of neurofibromatosis complicated by a large intrasellar (pituitary) cavernous angioma is reported. Vascular abnormalities, consisting of smooth muscle cell proliferation in the intima of the intermediate and small arteries, were also observed in branches of the renal and pulmonary arteries. An association between neurofibromatosis and intracranial cavernous angioma is discussed.

Isolated Central Nervous System Arteriopathy with Multiple Aneurysms in an Adolescent A Case Report

A 17 year old male suffered recurrent subarachnoid hemorrhages due to multiple aneurysms in the distal branches of the cerebral arteries. Autopsy revealed arteriopathy as well as the aneurysms. The arteriopathy was widespread, affecting the distal branches of small and medium‐sized muscular cerebral arteries, as well as the anterior and posterior spinal arteries, and vasocorona. The arteriopathy was characterized by prominent intimal thickening, discontinuity or absence of the internal elastic lamina, and thinning and/or disappearance of smooth muscle in the tunica media with fibroplasia. Slight intimal thickening was also observed in the arteries of the circle of Willis and its major branches, as well as in the basilar artery. However, the arterioles, venules and veins showed no remarkable features. The arterial lesions were found only in the central nervous system. The multiple aneurysms in the distal branches of the cerebral arteries, which had produced the main symptoms and clinical signs, were due to the arteriopathy.

Experimental emphysematous bullae

The effects of methylchoranthrene and carrageenan on the lungs of rabbits were studied. Four out of five animal which were injected via the bronchus with a suspension of 100 mg 20-methylchoranthrene in 8 ml solution of 0.75% lambda carrageenan in saline developed emphysematous bullae in the treated lobes of the lungs two months later. Animals treated with carrageenan solution (group 1), a suspension of methylchoranthrene in 10% tween 60 solution (group 2), and saline (group 3), failed to demonstrate cystic lesions in the lungs, except for one animal in group 1. These results suggest that this is a good experimental animal model for emphysematous bullae.

ATYPICAL COLLAGEN DISEASE: Polymyositis, Prominent Hematoxylin Body Formation and Some Manifestations of Progressive Systemic Sclerosis

An autopsy case of polymyositis with prominent hematoxylin body formation in various organs sand tissues, florid focal and segmental necrotizing glomerulonephritis, and some manifestations of progressive systemic sclerosis was presented. A 34‐year‐old woman had erythematous edema on the face, joint pain, muscular weakness, cutaneous sclerosis and Raynauds phenomenon for about 5 years. She had also a long history of pulmonary tuberculosis. Autopsy revealed polymyositis involving skeletal, smooth and heart muscles. This was widespread consisting of focal and extensive primary degeneration of muscle fibers and Interstitial Inflammatory cell infiltrates near and surrounding small veins and venules accompanied by the derivation of hematoxylin bodies from inflammatory cell nuclei, and in the posterior pharyngeal muscles severely affected, muscle substance was literally erased, leaving interstitial fibrous tissues and blood vessels. This focally restricted, severe necrosis of the skeletal muscle gives a special feature to the polymyositis in the present case. The diagnosis of polymyositis with prominent hematoxylin body formation and some manifestations of progressive systemic sclerosis was applied as a rather descriptive designation, but yet it does not absolutely exclude the possibility of a variant of SLE in an additional effort to search for an underlying disorder.

Acute diffuse interstitial fibrosing pneumonitis and bilateral renal cortical necrosis.

An autopsy case of a 69‐year‐old male with acute diffuse interstitial fibrosing pneumonitis complicated by bilateral renal cortical necrosis was presented. Autopsy revealed acute diffuse interstitial fibrosing pneumonitis, bilateral renal cortical necrosis, non‐bacterial thrombotic endocarditis, involving the aortic and mitral valves, and some interesting vascular lesions, dissemination of fibrinoid change of arterioles and fibrin thrombus of small vessels in various organs; accumulation of polymorphonuclear leukocytes in the lumen of the smaller interlobular arteries and arterioles of the kidney with cellular infiltration and disintegration of the wall; severe disorganization of the wall with intraluminar and intramural fibrinous exudation in smaller branches of the hepatic artery; diminution and disarrangment of muscle fibers and patchy hyalinization in the media of the renal and interlobar arteries. The inter‐relationship between acute diffuse interstitial fibrosing pneumonitis, bilateral renal cortical necrosis which may be regarded as a ‘hallmark’ of the generalized Shwartzman reaction, and disseminated intravascular coagulation was discussed.