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Biomedical subjects

S Katayama

Publications and source records attributed to S Katayama.

At least 343 records · Page 19Linked to original sources
PubMed1990

Diffuse sclerosing variant of papillary carcinoma of the thyroid. A histopathological study of four cases.

We present four cases of an unusual diffuse sclerosing variant of papillary carcinoma of the thyroid occurring in Japanese women ranging in age from 17 to 42 years. Macroscopically, both lobes of the thyroid were involved, being diffusely enlarged and firm. Histologically, the tumor was characterized by squamous metaplasia of tumor cells, numerous psammoma bodies, extensive stromal fibrosis, severe lymphocytic infiltration with formation of lymph follicles, and thin bundles of smooth muscle cells in the fibrous stroma. The tumor islands were located mainly within the dilated lymphatic vessels and the metastatic tumor involved the bilateral cervical lymph nodes in all cases. It is assumed that papillary carcinoma of this type invades the thyroid lymphatics during the early stage and, without forming nodular lesions, disseminates to both lobes with extensive metastasis to the cervical lymph nodes. It should be noted that papillary carcinoma of this type often suggests chronic thyroiditis clinically because of the symmetrical enlargement of the thyroid and frequent positive anti-thyroid antibodies in the serum. Some workers have reported the prognosis to be unfavorable because of extensive lymphatic involvement, but the prognosis of this variant has not yet been defined.

Adolescent↗
PubMed1990

Hyperreninemia due to increased renal renin synthesis in BioBreeding Worcester rats.

It is well known that diabetes mellitus is often associated with hypertension. We previously reported the unresponsiveness of renin release to volume depletion with impaired renal prostaglandin E2 synthesis in rats with streptozotocin-induced diabetes. However, we have found that BioBreeding Worcester rats, spontaneously susceptible to diabetes mellitus either before or after the onset of diabetes, showed a pronounced fourfold to ninefold increase in plasma renin activity in comparison with control Wistar rats. Furthermore, these rats developed mild hypertension as high as 134 mm Hg after the age of 90 days. The hyperreninemia responded to 1-week sodium loading or restriction; the blood pressure increased during sodium loading. Oral administration of captopril (30 mg/kg) for 1 week resulted in a large blood pressure decrease (-47.1 +/- 5.9 mm Hg, n = 10) in comparison with controls (-17.0 +/- 4.7 mm Hg, n = 12). Vascular response to angiotensin II was also attenuated. Plasma angiotensin II levels were 5.7-fold higher and associated with a 1.5-fold increase of plasma aldosterone concentration compared with control rats, whereas angiotensinogen-plasma concentrations were lower than in control rats. The renal renin content determined enzymatically or histochemically was more enhanced in BioBreeding Worcester rats than in control rats, but the renal renin messenger RNA levels did not differ. These results suggest that the strain-specific hyperreninemia in BioBreeding Worcester rats might be due to posttranscriptional abnormalities of renal renin synthesis. Further work is needed to elucidate the specific mechanism or mechanisms responsible.

Angiotensin II↗
PubMed1990

[Reproductive and developmental toxicity study of mofezolac (N-22) (1)--Study by oral administration of N-22 prior to and early stages of pregnancy in rats].

Mofezolac (N-22), a newly developed analgesic and anti-inflammatory agent, at dose levels of 0, 10, 30 and 90 mg/kg/day were administered orally to males from pre-mating to mating period and to females from pre-mating to early gestation period. Effects on reproductive performance of both sexes, especially reproductive capability, and development of offspring were examined. 1. In male parents, no changes in body weight and food consumption were found in all male groups, but the increase in gastric mucosal lesions such as ulcers were observed in 30 and 90 mg/kg/day groups. 2. In female parents, the decrease in body weight and food consumption of 90 mg/kg/day group during early gestation period were found, but at necropsy no changes were shown in all female groups. 3. Reproductive capability, mating and pregnancy performance were not affected. 4. No effects of N-22 on fetuses were observed. 5. The suggestions were as follows: No effect dose levels (NOELs) for male and female general-toxicologically were 10 and 30 mg/kg/day, respectively. NOELs for reproductive capability and for fetal development were 90 mg/kg/day.

Administration, Oral↗
PubMed1990

[Reproductive and developmental toxicity study of mofezolac (N-22) (4)--Study by oral administration of N-22 during the perinatal and lactation periods in rats].

peri- and postnatal study of mofezolac (N-22), a new developed analgesic and anti-inflammatory agent, was carried out with Wistar rats. N-22 at dose levels of 0, 25, 50 and 100 mg/kg/day were administered orally to pregnant and subsequent delivered dams from day 17 of gestation through day 21 of lactation. Body weight gains of dams treated with 50 and 100 mg/kg/day were depressed during perinatal period. Prolongation of pregnancy period, low performance of pup care with decrease in body weights and food consumptions were observed in 100 mg/kg/day group. Decrease in number and birth index, increase in number of stillborns and tendency to decrease in viability index on day 4 were found in 100 mg/kg/day group. Other parameters of development, behavior or reproductive capability of F1 animals showed no changes related to administration of N-22. It was suggested that no effect dose levels of N-22 were 25 mg/kg/day for dams viewpoint of general toxicity and that was 50 mg/kg/day for dams on reproductive performance and for offspring on development.

Administration, Oral↗
PubMed1990

Effect of captopril on glucose concentration. Possible role of augmented postprandial forearm blood flow.

The goal of this study was to evaluate the effects of captopril on plasma glucose concentration. The daily profiles of the plasma glucose levels were determined in 12 non-insulin-dependent diabetic normotensive subjects, treated with or without captopril at a dose of 25 mg 3 times/day. Forearm blood flow was also measured by strain-gauge plethysmography. Administration of captopril improved the daily profile of the plasma glucose level. Postprandial forearm blood flow was also augmented 2 h after a meal. These results suggest that angiotensin-converting enzyme inhibitors may improve glucose metabolism in diabetic subjects, possibly through enhancement of blood flow to skeletal muscle.

Blood Glucose↗
PubMed1990

Successful removal of an angiographically occult arteriovenous malformation of the ventral medulla.

A case with an angiographically occult arteriovenous malformation (AVM) of the ventral medulla presenting with progressive motor and sensory deficits is reported. The AVM, about 1 x 1 x 0.5 cm in size, accompanied by intramedullary haematoma, was successfully removed through a small incision placed in the right ventrolateral medulla between the vagus and the hypoglossal nerves. The patient's neurological symptoms improved after surgery.

Cerebral Hemorrhage↗
PubMed1990

Pharmacological activities of a novel thienodiazepine derivative as a platelet-activating factor antagonist.

(S)-(+)-6-(2-Chlorophenyl)-3-cyclopropanecarbonyl-8,11- dimethyl - 2,3,4,5 - tetrahydro - 8H - pyrido[4',3':4,5] thieno[3,2-fl-[1,2,4]triazolo]4,3-a][1,4]diazepine (E-6123) is a newly synthesized platelet-activating factor (PAF) antagonist. The effects of E-6123 on in vitro and in vivo PAF-induced responses were investigated. The IC50 values of E-6123 on 3H-PAF binding to human and guinea pig platelets were 2.7 and 3.0 nmol/l, respectively, and those on PAF-induced platelet aggregation in platelet-rich plasma of human, guinea pig and beagle dog were 10.1, 14.7 and 16 nmol/l, respectively. Oral administration of E-6123 at 3 and 10 micrograms/kg to dogs inhibited ex vivo PAF-induced platelet aggregation in a dose-dependent manner. In guinea pigs, E-6123 at 3 micrograms/kg completely inhibited ex vivo PAF-induced platelet aggregation up to 8 h and the inhibition was still significant at 24 h after administration. Occupancy of the platelet PAF receptor by E-6123 at 3 h and 24 h after administration amounted to 80% and 56%, respectively. Bronchoconstriction induced by PAF injection in guinea pigs was inhibited dose-dependently by oral or intravenous administration of E-6123 at similar doses. The IC50 value of E-6123 at 3 h after oral administration was 1 microgram/kg. Oral administration of E-6123 at 3 micrograms/kg inhibited the bronchoconstriction by more than 90% up to 8 h. Hemato-concentration induced by PAF injection in guinea pigs was inhibited by oral administration of E-6123 at 10 micrograms/kg. E-6123 also protected mice from PAF injection-induced death in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Alteration of muscarinic receptor subtypes in CA1 field of hippocampus in senile dementia of Alzheimer type: an autoradiographic study.

This investigation confirmed decreases in muscarinic acetylcholine receptor (mAChR) concentration in the hippocampus of patients with senile dementia of Alzheimer-type (SDAT) using a binding assay with homogenate. We performed quantitative in vitro autoradiography of mAChR in the hippocampus obtained at autopsy from non-demented controls and SDAT patients, who had a marked memory disturbance since the early stage. 3H-QNB (1.09nM) and 3H-pirenzepine (18.0nM) were used as ligands to label total mAChR and M1 receptors, respectively. Total mAChR and M1 receptor densities showed a decrease by about 20% and 25%, respectively, in the CA1 area of SDAT cases, when compared with that of normal control cases. No changes were observed in the dentate gyrus, CA3, subiculum or entorhinal cortex. These observations are thought to be partly causative of the marked memory deficits which appeared in these cases.

Adult↗
PubMed1990

[A case of hepatocellular carcinoma treated by intrahepatic arterial administration of anticancer agents: serial determination of the concentration of the chemotherapeutic agents in serum and dialysate during hemodialysis].

The concentration of adriamycin (ADR) and mitomycin C (MMC) were measured in serum and dialysate in a patient with hepatocellular carcinoma complicating chronic renal failure. ADR at a dose of 20 mg and MMC at 10 mg were administered through the hepatic artery or peripheral vein during hemodialysis. ADR and MMC became undetectable after 24 hours and 2 hours, respectively. On the other hand, while MMC was detected in dialysate, but ADR was not. Consequently, it was speculated smaller molecular weight of MMC (334.34) than that of ADR (579.99) might be responsible for the appearance of MMC in dialysate. These results suggest that hemodialysis may be effective in reducing side effects of certain anticancer agents. Serum concentration of the anticancer agents injected through hepatic artery was similar to that injected intravenously.

Adult↗
PubMed1990

[A case of Hurst's encephalitis complicated by hepatoma].

The patient, a 29-year-old female, was hospitalized because of clouding of consciousness, fever and right hemiplegia 4 days after the onset. On first examination she was found having fever in the 37 degree range, positive CRP, hepatomegaly, anemia and hepatic function impairment. Neurological examination revealed somnolence, conjugate deviation to the left and stiff neck. The muscular power measured about 3+ for the upper extremities and 0 for the lower extremities. Babinski sign was present on the right side. The spinal fluid showed an increase in cell counts, especially the neutrophil count. CT scans showed diffuse white-matter hypodensity in the left hemisphere. Soon after admission the patient fell into coma and died 6 days after admission. Autopsies led to a diagnosis of Hurst's encephalitis complicated by hepatoma with liver cirrhosis. It was reported that the immune complex was found in 25.9% of liver cirrhosis patients. From this fact it is suggested that Hurst's encephalitis might be elicited by some immunological mechanism.

Acute Disease↗
PubMed1990

Effects of anticholinergic antiparkinsonian drugs on binding of muscarinic receptor subtypes in rat brain.

Anticholinergic antiparkinsonian drugs have been widely used for the treatment of extrapyramidal disorders for a long time although their pharmacological characterization has been unclear. We studied the rank of potency of the effects of anticholinergic antiparkinsonian drugs to binding of 3H-QNB and 3H-PZ and calculated the affinity of each drug to the M1 receptor. All the drugs were potent inhibitors of 3H-QNB and 3H-PZ binding. The order of potency for 3H-QNB being: mazaticol greater than atropine greater than piroheptine greater than trihexyphenidyl greater than biperiden greater than ethopropazine greater than pirenzepine. The order of potency for 3H-PZ being: mazaticol greater than atropine greater than trihexyphenidyl greater than biperiden greater than ethopropazine greater than pirenzepine. Ki ratio indicated that trihexiphenidyl and biperiden bound to the M1 receptors selectively with high affinity and mazaticol would bind to the M2 receptors with higher affinity than atropine. These data suggest that we may be able to consider the pathophysiology of some extrapyramidal disorders based on the therapeutic efficacy of anticholinergic drugs which selectively affect M1 or M2 receptors.

Animals↗
PubMed1990

Increase of muscarinic receptor following kainic acid lesions of the nucleus basalis magnocellularis in rat brain: an autoradiographic study.

We observed changes in cholinergic markers in rat brain seven days after lesioning the nucleus basalis magnocellularis (nbm) with kainic acid. In histochemical preparations stained for acetylcholinesterase (AChE), there was a marked loss of large AChE reactive neurons within and beneath the nbm on the injected side, and the AChE positive fibers were greatly decreased particularly in the IV-VI layers of the frontal and parietal cortices ipsilateral to the kainate lesion. Using in vitro receptor autoradiography, we found a significant increase (about 25%) in 3H-QNB binding sites in the I-IV layers of the ipsilateral frontal and parietal cortices (p 0.05, Student's t-test). The area with decreased AChE activity and increased density in 3H-QNB binding sites corresponded to the innervation of the cholinergic system arising from the nbm. The increase of density in 3H-QNB binding sites was considered to reflect the postsynaptic denervation supersensitivity.

Acetylcholinesterase↗
PubMed1989

A new hypoglycemic agent, midaglizole, blunts diabetic platelet aggregation: a possible role of alpha 2 blockade.

A newly developed alpha 2 blocker, midaglizole (DG-5128, 2-[2-(4,5-dihydro-1H-imidazol-2-yl)-1-phenylethyl] pyridine dihydrochloride sesquihydrate) has been shown to have a hypoglycemic action in healthy controls as well as in diabetics. Since human platelets are rich in alpha 2 receptors, the effects of midaglizole on platelet aggregation were investigated. In normal controls, ADP- or epinephrine-induced platelet aggregation was significantly inhibited 2 h after oral administration of 300 mg midaglizole. Midaglizole also suppressed diabetic platelet aggregation stimulated by 10 or 100 microM epinephrine and delayed the initiation of collagen-induced aggregation at 30 micrograms/ml. In vitro addition of midaglizole at 9 or 90 microM significantly inhibited epinephrine-induced platelet aggregation. Furthermore, long-term administration of midaglizole suppressed diabetic platelet aggregation induced by 0.5-1 microM ADP or 1 microM epinephrine. These results suggest that alpha 2 blockade not only blunts diabetic epinephrine-induced platelet aggregation but also affects ADP- or collagen-stimulated platelet aggregation, indicating that this alpha 2 blocker may offer a new approach to the treatment of diabetic microangiopathy.

Adrenergic alpha-Antagonists↗
PubMed1989

Somatostatin increases intracellular Ca2+ concentration in cultured rat hippocampal neurons.

Changes of intracellular Ca2+ concentration [( Ca2+]i) in response to somatostatin were measured in cultured rat hippocampal neurons on a single cell basis by fura-2 fluorometry. Somatostatin increased [Ca2+]i dose-dependently and this effect was completely blocked in either Ca2+-depleted medium or LaCl3-containing medium. In addition, omega-conotoxin GVIA completely inhibited the effect of somatostatin. Our results indicate that somatostatin receptors couple with N-type voltage-sensitive Ca2+ channels in cultured rat hippocampal neurons.

Animals↗
PubMed1989

Cysts of the pineal gland. A new clinical entity to be distinguished from tumors of the pineal region.

Thirty-two cases of pineal cyst diagnosed by magnetic resonance imaging (MRI) were reviewed and are described. The pineal cyst was demonstrated to be an area with slightly less intensity than the surrounding tissue and with slightly greater intensity than the CSF on T1-weighted images. On the T2-weighted images this lesion was identified as a high-intensity area with smooth margins and was homogeneous in nature. In three cases presenting with headache, compression of the vein of Galen was identified, and compression of the quadrigeminal plate was demonstrated in five cases. No patients presented with both pineal and quadrigeminal lesions. Of the cases, 63% were not detected by CT scanning alone. There were two cases in which the cyst ruptured and collapsed spontaneously during follow-up. It is emphasized that the presence of this lesion, which was more frequent than previously expected, should be kept in mind when diagnosing pineal tumors and should not be misdiagnosed. Surgery should not be undertaken unless the lesion produces symptoms due to the compression of the quadrigeminal plate, aqueduct, or the vein of Galen.

Adolescent↗
PubMed1989

Effect of captopril or enalapril on renal prostaglandin E2.

Since one of the hypotensive mechanisms of angiotensin-converting enzyme inhibitor (ACEI) has been suggested to be mediated through the renal kinin-prostaglandin (PG) axis, the present study was designed to investigate the effect of captopril (C) or enalapril (E) on renal PGE2 excretion or synthesis. Wistar male rats (BW 200-250 g) were given orally captopril at 30 mg/kg/day or enalapril at 10 or 30 mg/kg for one week. Before and after ACEI, blood pressure (tail cuff method) as well as PRA and urinary PGE2 excretion was determined. Renopapillary slices were obtained from some of the rats including controls and incubated to determine PGE2 synthesis. C or E administration resulted in a blood pressure decrease of 21 to 36 mm Hg with an increase in PRA. Urine volume and sodium excretion increased after daily treatment with C or E at 30 mg/kg. Urinary PGE2 excretion increased 1.4-fold in response to C, but not to E. Papillary PGE2 synthesis demonstrated a marked decrease 2 h after in vivo administration of either ACEI compared to controls. However, when C or enalaprilat was added in vitro to renal slices obtained from controls, only C at 10(-5) M showed a significant 2-fold increase in renal PGE2 synthesis. These results suggest that (1) renal PGE2 synthesis may be dependent on circulating angiotensin II. (2) C, but not enalaprilat, has a direct stimulatory effect on renal PGE2 synthesis and (3) renal PGE2 may not be involved very much in the hypotensive effect of ACEI.

Animals↗