Biomedical subjects
Publications and source records attributed to H Imai.
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The distribution patterns of aminergic and cholinergic nerve fibers in the feline spinal blood vessels were studied by means of amine histofluorescence and acetylcholinesterase (AChE) staining. The anterior spinal artery had a dense network of aminergic and AChE-positive (probably cholinergic) nerve fibers. The posterior spinal vein, in contrast, had only aminergic nerve fibers. Intraparenchymal small blood vessels in the spinal cord also had strongly fluorescent (probably peripheral) aminergic nerve fibers. This was quite a characteristic feature in the spinal cord. The distribution pattern and the density of these two sorts of nerve fibers widely varied with the individual segment of the spinal cord. The thoracic spinal cord had the lowest number of these nerve fibers throughout the spinal cord. This fact may give a clue to explain why the thoracic spinal cord is most susceptible to ischemic change.
By an immunohistochemical technique, vasoactive polypeptide (VIP)-and substance P-containing nerve fibers are observed in the cerebral blood vessels. VIP-containing nerve fibers distribute in a spiral pattern, similar to the muscle cell distribution pattern. Under an electron microscopic observation, VIP-immunoreactive terminals lie just near to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers show a meshwork pattern in the outer layer of the adventitia. In combination of acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers reveal almost same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role of smooth muscle control of the blood vessels, while substance P-containing nerve fibers may not take part in muscle control.
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In a case of primary reticulum cell sarcoma in the brain, histologically verified by biopsy, the tumor regressed twice on a CT scan without radiotherapy. The systemic freezing phenomenon was seen as a main clinical symptom. The patient, a 44 year-old male, first complained of decreased livido and festinating speech. He also showed frozen gait, micrographia, a decrease in spontaneity and urinary incontinence. Four months after onset he was hospitalized. Neurological findings on admission revealed freezing of gait, writing, and speech, but there was no weakness of muscles with normal tendon reflexes, and normal muscular tone. In the CT scan on admission, there were high density areas mainly in the head of the right caudate nucleus, the medial deep portion of the right frontal lobe, the right side of the hypothalamus, the anterior thalamus, the globus pallidus. There were also nodular-type enhanced effects in the same areas. Regression of the tumor was seen on the CT scans after administration of betamethasone. The tumor which had again increased in size regressed spontaneously without the use of steroids after 3 months. Thereafter, the tumor gradually became larger and an open biopsy was performed. Histopathological findings showed a reticulum cell sarcoma. There were no findings of systemic malignant lymphoma. Such intracranial malignant lymphomas showing repeated regression including spontaneous one are very rare in the literature. The freezing phenomenon in this case started with festinating speech and spread to writing and gait. L-DOPA had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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The distribution of nerve fibers in the cerebral blood vessels was studied by a catecholamine histofluorescence method, acetylcholinesterase (AChE) staining and immunohistochemistry. The ultrastructure of the terminal boutons in the vessel wall was also studied. In the adventitia of the cerebral artery, green fluorescence aminergic fibers and brownish AChE-positive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. The highest density of aminergic fibers were found in the dural sinus and the second highest in the internal cerebral vein. Serotonin immunoreactive nerve fibers were found along small intraparenchymal blood vessels such as perforating arteries in the brain stem, and arterioles and venules in the cerebral cortex. Under ultrastructural observation, a serotonin immunoreactive terminal was demonstrated in conjunction with the basement membrane of the capillary.
In order to search into the mechanism of the potassium contracture of the dog coronary artery the effects of procaine were studied in the isolated smooth muscle preparation of the dog coronary artery. Procaine is a substance which is known to specifically inhibit the calcium-induced calcium release mechanism. A dose-related relaxation of the potassium contracture was observed with procaine. However, the increase in La3+-resistant 45Ca uptake as measured by the Karaki and Weiss' method (1979) was not inhibited. As reported in a previous paper, caffeine induced a phasic contraction of the fully-depolarized preparation in a calcium-free EGTA containing medium. Procaine produced a dose-related inhibition of this contraction. These findings suggest that the potassium contracture of the dog coronary artery is dependent on the calcium-induced calcium release mechanism. Since the potassium contracture of this preparation can be relaxed by calcium antagonists, it may be inferred that the calcium influx through the voltage-dependent channels may represent the initiation mechanism of the calcium-induced calcium release process.
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Cytogenetic studies of recombination in males of Drosophila ananassae were carried out by examining F1 males derived from he mating of marker females, b se; bri ru of the BS stock, with males of two wild strans, TNG and L8. The male recombination values in both sections b-se (chromosome 2) and bri-ru (chromosome 3) are high in TNG F1 but extremely low in L8 F1. We demonstrate the presence of chiasmata in TNG F1 males at a frequency capable of accounting for the observed recombination values. A unique series of "iso-site aberrations" was also observed in TNG F1 males. Because of a parallelism in the distribution pattern between the chiasmata and the iso-site aberrations, we propose that recombination in males of D. ananassae is meiotic in origin and that the iso-site aberrations are related to chiasma formation.
Pigmented (Long-Evans) and albino (Wistar) rats were chronically exposed to an organophosphate pesticide (fenthion). Fenthion (50 mg/kg) was administered subcutaneously twice a week for 1 year; the total dosage for each animal ranged from 1.6 to 1.8 g. Concurrent with the fenthion administration, the amplitude of the scotopic electroetinogram (ERG) gradually declined, disappearing by the 12th month in all treated pigmented rats. For the albino experimental rats, however, the ERG amplitude disappeared as early as the 6th month in 7 out of 15 treated animals. Funduscopically, degeneration of the retina was observed in all rats when ERG responses had disappeared. Histopathological studies confirmed degeneration of the sensory retina and marked abnormalities in the pigment epithelium cells. Treated pigmented rats also had reduced a rhodopsin concentration in the retina by the 3rd month even though the photoreceptors were structurally normal. Interestingly, the plasma vitamin A levels remained normal and liver stores of vitamin A actually increased during the course of the study. Levels of butylcholinesterase in plasma and liver, on the other hand, were extremely reduced after 3 months of fenthion treatment. In general, the biochemical and functional (ERG) changes appeared before any structural damage could be detected in the retina.
Hybrid hares provide a model for induction of aortic atherosclerosis. The basic dietary regimen consisted of cholesterol-supplemented and nonsupplemented commercial pellets alternating at 1-week intervals for up to 18 months. Controls were fed nonsupplemented pellets. Control aorta features included branch cushions, intimal thickenings unrelated to branches, and several longitudinal layers of smooth muscle in the outer media. Branch cushions extended longitudinally in the main vessel, and had multidirectional, streamlike bundles of smooth muscle in the intima and media. Intimal thickenings unrelated to branches occurred as longitudinal patches, most frequently in the ventral quadrant. The adjacent media had a regular array of cells. Raised lesions concentrated at branch orifices and in the ventral quadrant. Lesions involved up to 80% of the thoracic and 40% of the abdominal aorta by 5 months. Predominant lesions consisted of superficial fibromuscular tissue and deeper foam cells and stainable lipids. Some of these lesions were atheromata with fibrous cap. Fibromuscular plaques, 120 to 150 micron thick, had a few superficial foam cells and hydropic degeneration. Foam-cell lesions were also observed. Data obtained suggest the importance of branch cushions and intimal thickenings unrelated to branches, and of the periods on nonsupplemented pellets.
A fluorographic method is described using X-ray film analysis for the determination of delivery of radiolabeled tracer substances both in Agar plates and in tissue sections. This method is most useful in neuroanatomical autoradiographic studies for providing rapid identification of delivery, placement, and extent of an injection site after iontophoresis or pressure injections of radiolabeled axonal tracer substances.
Platelet aggregation response to various stimulants was examined in 18 unmedicated schizophrenic patients, 13 medicated patients, and 13 control subjects. Platelet aggregation response to epinephrine decreased only in unmedicated schizophrenic patients. Clinical improvement in seven patients after neuroleptic medication was significantly correlated with an increase in platelet aggregation response to arachidonic acid, and nonsignificantly to epinephrine, dopamine, and serotonin. The inhibitory effect of prostaglandin E1 on platelet aggregation response to adenosine diphosphate was investigated in seven unmedicated schizophrenic patients, six medicated patients, and eight controls. The inhibitory effect of prostaglandin E1 on platelet aggregation response to adenosine diphosphate was significantly reduced in all unmedicated schizophrenic patients. Neuroleptic medication had some effect in normalizing aberrant sensitivity to prostaglandin E1 in those patients, although acute medication induced an adverse reaction in the controls.
The distribution of nerve fibers in the cerebral veins was studied by catecholamine fluorescence simultaneously with acetylcholinesterase (AChE) histochemistry. A comparison of nerve fibers in the cerebral arteries was made. The ultrastructure of terminal boutons in the veins fixed with potassium permanganate was also studied. In the adventitia of the cerebral artery, green fluorescent aminergic fibers and brownish AChE-reactive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. Catecholamine fluorescent varicose fibers were detected in the dural sinus, the internal cerebral vein, and the superficial vein of Labbé. The highest density of aminergic fibers was found in the dural sinus and the second highest in the internal cerebral vein. Most of the terminal boutons in the adventitia of the cerebral veins were found adjacent to a muscle-like cell and showed only cored vesicles under electron microscopy. Results of our study suggest that the cerebral venous system has a neurogenic innervation, mainly from aminergic fibers, which is different from the neurogenic supply to the cerebral arterial system.
A 41-year-old female was evaluated for asymptomatic proteinuria and thrombocytopenia. The renal biopsy disclosed mild to moderate mesangial proliferation, and the immunohistology showed granular deposition of dominant IgA and C3 in the mesangium, which is consistent with IgA nephritis. Thrombocytopenia was EDTA-dependent pseudothrombocytopenia type 1. Heparinized blood restored the platelet count to normal. Serological examinations revealed that the platelet agglutinin was IgA, and the platelet clumping required both EDTA and IgA-related agglutinin. Thus, the present case adds the combination of IgA nephritis and pseudothrombocytopenia to the spectrum of the so-called thromborenal syndrome. In view of recent findings that platelet agglutinins belong to immunoglobulins or fractions, occurring frequently in a variety of immunologically abnormal situations, IgA-related agglutinin as seen in this patient may have more than a chance association with IgA nephritis.
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