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Biomedical subjects

K Kamata

Publications and source records attributed to K Kamata.

At least 307 records · Page 17Linked to original sources
PubMed1983

[Culture of mouse embryo for the toxicological evaluation of drugs in vitro. (1). Establishment of in vitro culture system and effect of 6-mercaptopurine on development of early stage embryo].

The basal conditions for culture of early mouse embryo in vitro were examined for drug evaluation. Among the media tested, BMOC-III was most suitable for mouse embryo culture. Changing the medium at 1 or 3 hr after culture was harmful to the survival and/or development of early staged embryos, whereas at 12 or 24 hr after culture, changing of the medium showed slight effect on embryo development. Eight-cell staged embryos were more resistant to changing medium that two-cell staged ones. Preliminary work using a suitable culture system established that exposure to 6-mercaptopurine for 12 or 24 hr resulted in a prolonged developmental rate at each stage. The effects showed a dose-dependent relationship with the 24 hr exposure. It was suggested that inhibition of the developmental rate during exposure resulted from a direct toxic effect on the cell and that the inhibition after exposure resulted from metabolic toxicity.

Animals↗
PubMed1982

Childhood type polymyositis and rapidly progressive glomerulonephritis.

A 21-year-old women developed rapid muscle weakness and quickly deteriorating renal function. Pathological findings revealed prominent vasculitis in the muscle and crescentic glomerulonephritis. Combined steroid and heparin treatments could not prevent the development of the renal lesion, but the muscle involvement had soon improved. Although the pathogenesis remains unclear, immune complexes may be involved in this renal lesion.

Adult↗
PubMed1982

Involvement of the dopaminergic system in the regulation of the caudate spindle in the rat.

In an attempt to study the neural mechanism of the development of the caudate spindle, effects of dopamine agonist or antagonists and baclofen on the spindle were studied in gallamine-immobilized rats. The spindle was significantly enhanced by chlorpromazine, haloperidol and pimozide, and these effects of drugs were completely antagonized by apomorphine. A marked prolongation of the duration of the spindle was observed by the treatment with baclofen, and this side effect was antagonized by apomorphine but not by methysergide, eserine or picrotoxin. These results suggest that the dopaminergic system may play an important role in the development of the caudate spindle in the rat, i.e. as a negative modulatory system in the manifestation of the caudate spindle.

Action Potentials↗
PubMed1982

Pseudoplaque formation by cytophilic immunoglobulins in the sera of lupus patients as measured using reverse haemolytic plaque assay.

Normal human peripheral blood lymphocytes cultured in vitro with lupus sera (LS) were studied for their possible immunoglobulin (Ig) secretion using reverse haemolytic plaque assay (RHPA). Plaque forming cells (PFC) produced in cultures with LS (2,323 +/- 858 PFC/10(6) cultured cells) significantly increased in number compared to the control cultures with normal human serum (206 +/- 43, P less than 0.05). However, the artifactual nature of the PFC formation due to cytophilic Ig in LS subsequently became evident from the kinetic curves, trypsinization or medium change at the end of the culture period, radiation of cells on the first day of culture, or by depletion of nylon wool column-adherent cells from the culture system. These cytophilic Ig were observed in 56% of the sera obtained from untreated lupus patients. Thus, their possible interference with the resultant spurious plaque formation might be difficult to eliminate when performing RHPA in lupus patients.

Antibodies↗
PubMed1981

Multiple aneurysms of the vertebrobasilar system associated with fenestration of the vertebral artery.

A rare case of multiple aneurysms of the vertebrobasilar system associated with fenestration of the intracranial vertebral artery is reported. A search of the world literature revealed 56 other cases of the vertebral artery fenestration, mainly in reports from Japan. Only 11 cases of this association with intracranial aneurysms were reported, and none of these aneurysms were located on the posterior circulation. Association of multiple vertebrobasilar aneurysms and vertebral artery fenestration is rare.

Basilar Artery↗
PubMed1981

False aneurysm with subdural hematoma and symptomatic vasospasm following head injury.

A rare case of cortical false aneurysm in a subdural hematoma and symptomatic vasospasm following head injury without skull fracture is reported. Angiography led to the correct preoperative diagnosis and successful surgical treatment, although the patient's symptoms of acalculia, agraphia, and astereognosis, mainly due to the vasospasm of the proximal portion of the middle cerebral artery, remained unchanged. The mechanism of such a cortical false aneurysm and symptomatic vasospasm is discussed briefly.

Adult↗
PubMed1981

Brain tumors in tuberous sclerosis. Report of 4 cases.

We report on 4 cases of brain tumors associated with tuberous sclerosis. In each case the tumor was in the region of Monro's foramen and was associated with ventricular dilatation. Computer tomography scans, which were performed in 3 cases, revealed well-circumscribed high-density masses which were markedly enhanced by contrast medium. 3 patients underwent craniotomy. Total extirpation was performed in 2 patients. Both of them are doing well postoperatively. However, 1 patients whose tumor had been partially resected died of recurrence 6 years after surgery. The pathology of three tumors was different in each case: plump cell astrocytoma, hemangioma and astroblastoma.

Adolescent↗
PubMed1981

Effects of intracerebral administration of atropine and morphine on the caudate stimulation-induced caudate spindle in rats.

The electrical stimulation of the caudate nucleus could induce a caudate spindle in the rat as in case of the cat and monkey. The spindle was enhanced by atropine (3-10 mg/kg, i.v.) or morphine (3-10 mg/kg, i.v.) and the effect of these drugs were completely abolished by eserine (0.3 mg/kg, i.v.), but not by methysergide (1 mg/kg, i.v.), PCPA (400 mg/kg, i.p. for 3 days) or reserpine (3 mg/kg, i.p. for 2 days). An intraventricular injection of atropine (5-10 microgram/rat) or morphine (10 microgram/rat) exerted a facilitatory action on the spindle, while an intrathalamic and intracaudate injection of atropine (5-50 microgram/rat) showed a suppressive action. The spindle was also markedly enhanced by the microinjection of atropine (15-30 microgram/rat) or morphine (30 microgram/rat) into the reticular formation, and these actions were completely antagonized by eserine (0.3 mg/kg i.v.), but only partially by methysergide (4 microgram/rat, intraventricular administration.) These results suggest that the cholinergic system may play an important role in the regulation of the caudate spindle.

Animals↗
PubMed1981

[Pharmacological action of eptazocine (l-1,4-dimethyl-10-hydroxy-2,3,4,5,6,7-hexahydro-1,6-methano-1H-4-benzazonine). (III) Central action of eptazocine (author's transl)].

Pharmacological actions of eptazocine on the central nervous system were investigated by pharmacological and behavioral methods. Eptazocine produced sedation at low doses and Straub tail reaction in mice and ataxia in rats at high doses. In mice, eptazocine caused decreases in the spontaneous locomotor activities measured by the wheel cage and Animex methods, but caused an increase of the response in rats as determined by the open-field method. Eptazocine caused impairment of performance in the rotarod test and the traction test in mice, a decrease of activity of EMG, and an inhibition of flexor reflex in rats. Eptazocine decreased body temperature, potentiated pentobarbital-induced sleeping, and convulsion caused by pentylene-tetrazol in mice. Fighting behavior induced by electric shock and central stimulation effect of methamphetamine were inhibited by eptazocine in mice. Eptazocine showed an inhibiton of avoidance behavior in shuttle and skinner boxes in rats. These results suggest that eptazocine produces a non-specific inhibitory action on the central nervous system.

Analgesics↗
PubMed1981

Effects of narcotic and non-narcotic analgesics on the abdominal or tail stimulation-induced struggling in rats.

As a model, we used struggling induced by a repetitive stimulation of the tail or abdomen and two types of pseudoaffective responses were evoked in rats. The effects of narcotic and non-narcotic analgesics on these responses were alternately assessed. Narcotics were markedly effective in inhibiting struggling elicited by tail stimulation and slightly less effective in suppressing the abdominal stimulation-induced struggling. These effects on two types of struggling differed quantitatively but not qualitatively. On the other hand, non-narcotics such as aspirin (200 mg/kg, i.p.), aminopyrine (160 mg/kg, i.p.) and indomethacin (20 mg/kg, i.p.) had an inhibitory action on the struggling elicited by the tail stimulation but showed equivocal and far less inhibition on the abdominal stimulation-induced response. These two effects were quantitatively and qualitatively different because the slope of the dose-response curves were not in parallel. The action of baclofen appears to be ambiguous since it had distinctive inhibitory actions on both typed of struggling. However, baclofen can be classified into the latter group in that it exerted an inhibitory action on two types of struggling, in a quantitatively different manner. These results suggest that two types of struggling in rats provide a convenient means to assess the potency of analgesics.

Abdomen↗
PubMed1981

Effects of adrenal demedullation and peripheral noradrenaline-depleting agents on adrenocortical function and spleen in rats.

Adrenocortical functions of adrenal-demedullated rats (ADMx rats) and peripherally chemical-sympathectomized ADMx rats were studied by examining changes in the levels of serum and adrenal corticosteroids (CS). Resting levels of serum and adrenal CS were not influenced by adrenal-demedullation and peripheral chemical-sympathectomy with 6-hydroxydopamine. Diurnal variation in serum CS concentration was also unchanged, suggesting that peripheral adrenergic systems do not influence the basal function of hypothalamo-pituitary-adrenocortical axis. Exposure of ADMx rats to the stressful stimuli, however, resulted in lowered adrenocortical response with a lesser increase in serum CS concentration, while peripheral chemical-sympathectomy of ADMx rats with 6-hydroxydopamine or guanethidine caused a significant enhancement of adrenocortical response to the stress with elevation of the serum CS concentrations. These findings suggest that increased peripheral adrenergic activity may suppress the activation of the hypothalamo-pituitary-adrenocortical system as the animals were exposed to the stressful stimuli. Adrenal-demedullation produced no increase in spleen weight while chemical-sympathectomy by peripheral administration of 6-hydroxydopamine did produce a significant increase in the weight of this organ. Histological features following chemical-sympathectomy are described.

Adrenal Cortex↗
PubMed1981

[Pharmacological action of eptazocine (l-1,4-dimethyl-10-hydroxy-2,3,4,5,6,7-hexahydro-1,6-methano-1H-4-banzazonine). (II) Relationship between the analgesic action of eptazocine and brain 5-hydroxytryptamine (5-HT) (author's transl)].

The relationship between the analgesic action of eptazocine and brain 5-HT was investigated by pharmacological and neurochemical methods in comparison with pentazocine (PZC) and morphine (MOR). The analgesic effects of eptazocine, PZC, and MOR as determined by the pressure method were decreased by pretreatment with rho-chlorophenylalanine or 5,6-dihydroxytryptamine. The analgesic effects of all three drugs were also diminished by a lesion in the dorsal half of the spinal cord (C5-6) or the raphe magnus. A lesion in the central gray produced a decrease in the analgesic effects of MOR or PZC, but had a weak effect on that of eptazocine. All three drugs increased 5-hydroxyindole acetic acid (5-HIAA) levels in the brain stem, the striatum, and the spinal cord. In addition, eptazocine decreased the 5-HIAA level in the cortex and the 5-HT level in the hippocampus, but increased the 5-HT level in the spinal cord. An increase of 5-HIAA in the cortex and a decrease of 5-HT in the brain stem were observed after PZC-administration. On the other hand, MOR decreased the 5-HT level in the brain stem and striatum. These results suggest that the effects of eptazocine on 5-HT neurons are similar to those of PZC and MOR, but part of the action mechanism of eptazocine is different from those of PZC and MOR.

Analgesics↗