Search PubMed⌕ Search

Biomedical subjects

H Oyama

Publications and source records attributed to H Oyama.

At least 145 records · Page 8Linked to original sources
PubMed1990

[Plasma concentration of polymorphonuclear leukocyte elastase-alpha 1-proteinase inhibitor complex in patients with gastric ulcer].

To test the possible participation of activated leukocytes in the pathogenesis of gastric ulcer, plasma levels of polymorphonuclear leukocyte-elastase-alpha 1-proteinase inhibitor complex (PMN-EC), a discerning indicator for the activation of leukocytes, were determined in patients with gastric ulcer. Plasma levels of PMN-EC in patients with gastric ulcer (185.2 +/- 21.6 micrograms/l, mean +/- S.E.M.) were significantly higher than those in normal healthy subjects (67.6 +/- 4.4 micrograms/l, p less than 0.01). On the other hand, plasma levels of C-reactive protein and sialic acid increased in only 17.8% and 7.1% of patients with gastric ulcer, respectively. No significant correlation was observed between PMN-EC and the plasma levels of CRP or sialic acid. Plasma levels of PMN-EC decreased with the healing of the ulcerative lesion as judged by gastro-endoscopic observation. These findings suggested that activation of leukocytes might deeply be correlated with the pathologic mechanism of gastric ulceration and the measurement of PMN-EC might be useful for monitoring the patients with gastric ulcer.

Humans↗
PubMed1990

Radiation effect of gadolinium-neutron capture reactions on the survival of Chinese hamster cells.

In gadolinium-neutron capture reactions, prompt gamma rays with an energy spectrum of up to 7 MeV, X-rays and electrons are released. We measured the effect of radiation as a result of capture reactions on cultured Chinese hamster cells. Cells in the medium containing 5000 ppm gadolinium were exposed to thermal neutrons from a nuclear reactor. The survival curve for those cells exhibited a shoulder in the low neutron fluence region. The survival curve for cells exposed to thermal neutrons in the absence of gadolinium was a simple exponential function. To obtain 10% survival levels, 5.4 x 10(12) neutrons/cm2 were required for cells irradiated in the absence of gadolinium, and 1.55 x 10(12) neutrons/cm2 for those irradiated in the presence of gadolinium. The therapeutic ratio in gadolinium-neutron capture therapy depends on the difference in 157Gd concentrations between the tumor and normal tissues. Thus, our current effort has been to develop a method of selectively delivering 157Gd to tumors.

Animals↗
PubMed1989

Circadian rhythms for calcium, inorganic phosphorus, and parathyroid hormone in primary hyperparathyroidism: functional and practical considerations.

We obtained serial serum and urine samples from 14 patients with primary hyperparathyroidism both before and 3 to 9 months after excision of their parathyroid adenomas to (1) determine whether the circadian rhythms for calcium, phosphorus, and parathyroid hormone (PTH) previously described in normal human beings are disturbed in this disorder; (2) gauge the effect of surgical treatment on the patterns observed before intervention; and (3) ascertain whether time(s) of blood sampling can be defined for optimal biochemical detection of the disease. Significant rhythms for serum phosphorus, ionized calcium, PTH, urine phosphorus, and urine calcium were observed in many but not all patients before and after surgery. Nonetheless, collective analysis revealed the following: (1) diurnal patterns for serum ionized calcium, phosphorus, urine calcium, and urine phosphorus in patients with primary hyperparathyroidism both before and after surgery, whereas a rhythm for serum PTH was uniquely observed after surgical treatment; and (2) no significant correlation between preoperative serum ionized calcium and PTH but restoration of the expected reciprocal relationship between these variables after surgery. Although variability in individual expression of the rhythm for PTH precludes precise definition of a sampling "window" when hormone levels are likely to be highest, collection of data at points throughout the day helped establish the diagnosis of primary hyperparathyroidism in several patients with borderline serum biochemistries.

Adenoma↗
PubMed1989

Primary hyperparathyroidism: a new experimental animal model.

Although potentially useful in the understanding of hypercalcemic states, a satisfactory animal model of primary hyperparathyroidism has not been developed. Models that use transplants of supernumerary parathyroid (PT) glands or chronic parathyroid hormone (PTH) infusion are not ideal for many reasons. We report a new animal model in which athymic nude mice were used as recipients of human PT tissue heterografts. Three groups received 14, six, or one piece of PT adenoma tissue, and one group received six pieces of normal PT tissue. The significantly higher PTH levels in mice that received adenoma heterografts versus those with similar amounts of normal tissue suggest that adenomatous tissue is functionally distinct. A dose-response relationship between induction of hypercalcemia and the number of pieces implanted was in evidence, although only a small percentage of the mice with high PTH levels developed hypercalcemia. This differential response could be the result of any of several factors: (1) loss of ability to secrete bioactive PTH, (2) differing secretion rates among donor adenomas, (3) variability in host responsiveness to human PTH, and (4) requirement of additional factor(s) to generate consistently the hypercalcemia characteristic of human primary hyperparathyroidism.

Animals↗
PubMed1988

Cloning and expression of subtilisin amylosacchariticus gene.

The gene encoding subtilisin Amylosacchariticus from Bacillus subtilis var. amylosacchariticus was isolated and the entire nucleotide sequence of the coding sequence was determined. The deduced amino acid sequence revealed an N-terminal signal peptide and pro-peptide of 106 residues followed by the mature protein comprising 275 residues. There were discrepancies in 10 amino acids between the sequence elucidated from the nucleotide sequence and the published protein sequence (Kurihara et al. (1972) J. Biol. Chem. 247, 5619-5631). The nucleotide sequence was highly homologous to that of subtilisin E gene from B. subtilis 168, with discrepancies at 12 nucleotides out of 1,426 nucleotides we sequenced. Ten of them were found in mature subtilisin coding sequence, which resulted in two amino acid changes and another one was in the putative promoter region between two genes. The productivity of subtilisin in culture broth of B. subtilis var. amylosacchariticus was much higher than that of B. subtilis 168. The enzyme gene was inserted in a shuttle vector pHY300PLK, with which B. subtilis ISW1214 was transformed. The proteolytic activity found in the culture broth of the transformed bacterium was 20- and 4-fold higher than those of the host strain and B. subtilis var. amylosacchariticus, respectively. Subtilisin Amylosacchariticus was easily purified to a crystalline form from culture filtrate of cloned B. subtilis, after a single step of chromatography on CM-cellulose.

Amino Acid Sequence↗
PubMed1988

Provocation of a paradoxical growth hormone response to corticotropin-releasing hormone by pretreatment with metoclopramide in patients with acromegaly and normal subjects.

Two of 7 patients with acromegaly and one of 7 normal subjects exhibited a paradoxical rise in growth hormone (GH) to human corticotropin-releasing hormone (CRH) when pretreated with metoclopramide, although CRH alone did not induce an increase in GH. In one of these two patients with acromegaly, the GH increase to metoclopramide alone also reached the criteria of a paradoxical response. These two acromegalic patients showed a GH increase to metoclopramide pretreatment before and up to two months after surgery. In another acromegalic patient, whose GH level remained high 5 months after surgery, metoclopramide induced an increase in GH level, while in a patient who had an above-normal GH level 18 months after surgery, the resumption of physiological GH secretion after surgery was evidenced by a postoperative absence of a GH response to metoclopramide. It is suggested from these results that the GH response to metoclopramide and the metoclopramide-provoked GH response to CRH in patients with acromegaly result from the secretion of GH from nonadenomatous cells of the pituitary.

Acromegaly↗
PubMed1988

[An immunohistologic study of reactive lymphocytes in breast tissue].

A series of T-cell specific monoclonal antibodies (Leu-4; CD-3, OKT-4; CD-4, OKT8; CD-8) and a B-cell specific monoclonal antibody (Leu-12; CD-19) were used to detect the localization and intensity of lymphocytes in breast tissue. Frozen sections of 12 fibrocystic diseases, 11 fibroadenomas and 17 carcinomas of the breast were examined during this study. CD-3 and CD-8 positive lymphocytes predominated in and around the ducts of the fibrocystic disease and the fibroadenoma. Similarly, almost all of the reactive lymphocytes around the cancerous tissue also were CD-3 and CD-8 positive suppressor/cytotoxic cells.

Adenofibroma↗
PubMed1988

[AUFRAP therapy: combined modality treatment of malignant gliomas with intraarterial infusion of ACNU].

A method of combination therapy was proposed for the treatment of malignant gliomas, and the clinical results were reported. This combination consisted of ACNU (nimustine), UFT (tegafur + uracil), Radiation, vitamin A and PSK (krestin), and was named AUFRAP therapy. Intracarotid infusion of ACNU (100 or 150 mg/body) was done after the administration of vitamin A (100,000 units), in the first and last week of radiation therapy with a total dose of 60-70 Gy. UFT (400-600 mg/day) and PSK (3g/day) were also given orally. After the induction of remission, patients were treated in the outpatient clinic under a similar maintaining protocol. Two patients who received 150 mg of ACNU and daily 600 mg of UFT in combination with radiation therapy showed severe myelosuppression in the early stage of treatment, and the combination therapy was aborted. Two of four patients who received 100mg of ACNU and daily 400mg of UFT did not show such severe side effects and two showed transient, moderate myelosuppression and vomiting. The serum phenitoin concentration doubled and was thought to be a side effect of tegafur. All four patients completed the induction protocol and follow-up CT scans disclosed shrinkage of the remained tumors, decreased contrast enhancement or no evidence of recurrence. Interactions of these drugs and radiation were discussed and the literature was reviewed.

Adult↗
PubMed1988

Renal handling of hypoxanthine and xanthine in normal subjects and in four cases of idiopathic renal hypouricemia.

Pyrazinamide (PZA) was used to study the renal handling of hypoxanthine, xanthine and uric acid in 2 normal subjects and in 4 patients with idiopathic renal hypouricemia; one patient was classified as having a postsecretory reabsorption defect, whereas the others were classified as having a presecretory reabsorption defect. In normal subjects, PZA suppressed strongly the excretion of xanthine as well as uric acid; however, it showed a weak effect on that of hypoxanthine. PZA suppressed all excretion of these 3 compounds in the patient with postsecretory reabsorption defect. PZA showed almost no effect on the excretion of either hypoxanthine, xanthine or uric acid in the patients with presecretory reabsorption defect.

Adult↗
PubMed1987

Pituitary-adrenocortical response to metoclopramide in patients with acromegaly and prolactinoma: a clinical evaluation of catecholamine-mediated adrenocorticotropin secretion.

We have demonstrated that metoclopramide stimulates cortisol secretion at least in part by a stress-mediated effect in normal men. To examine further the effect of the drug on the hypothalamo-pituitary adrenal system, we studied the cortisol response to 20 mg metoclopramide in patients with acromegaly, prolactinomas, and functional hyperprolactinemia and compared the results with the responses to insulin-induced hypoglycemia. In some patients, the effects of metoclopramide on CRH-induced ACTH and cortisol increase were studied to determine whether a change in dopaminergic (catecholaminergic) activity altered CRH stimulation of pituitary-adrenal function. No cortisol response to 20 mg metoclopramide occurred in 13 tests on 8 of 9 patients with prolactinoma or acromegaly with hyperprolactinemia, whereas both acromegalic patients without hyperprolactinemia had a response. All of the patients had a normal cortisol response to insulin-induced hypoglycemia. Pretreatment with metoclopramide enhanced the CRH-induced cortisol increase from 30-120 min after CRH in normal men, but only at 15 and 30 min in 5 agromegalic patients. The results suggest that metoclopramide acts in the hypothalamus to release ACTH through a dopamine antagonist-mediated (catecholaminergic) mechanism, and that metoclopramide may act additively with CRH to stimulate ACTH secretion in normal men. The absence of a metoclopramide-induced cortisol response in patients with acromegaly or prolactinomas and the absence of a normal cortisol response to metoclopramide-CRH in acromegalic patients could be due to endogenous catecholamine deficiency in these patients.

Acromegaly↗
PubMed1985

New application of high-performance liquid chromatography for analysis of urinary C-peptide.

A successful application of high-performance liquid chromatography for analysis of urinary C-peptide is described. Samples (1.0 ml of human urine) were first subjected to gel chromatography to remove interfering substances, and then applied to a reversed-phase column (LiChrosorb RP-18, 7 micron). The detection of C-peptide was performed using a highly specific radioimmunoassay. With the newly developed techniques, at least four forms of immunoreactive C-peptide were detected in human urine. One of these peptides was indistinguishable from authentic C-peptide. The present study has clearly demonstrated the heterogeneity of urinary C-peptide.

Adult↗
PubMed1985

Insulin and C-peptide secretion from B cells in human subjects stimulated with glucose.

Two groups of immunoreactive insulin in human sera were reported by Kakita et al. (4), using gel chromatography after acid-alcohol extraction. These analogs were noted not only in circulating human sera but also in incubation medium and incubated human pancreas. The release of these insulin analogs was discussed in a previous report (5). The circulating C-peptide immunoreactivity was separated into two groups on a Bio-Gel column, and the early peak should not be proinsulin but an associated C peptide (6). These analogs of insulin were separated by the methods of ion-exchange chromatography, isoelectric focusing, gel electrophoresis, and gel chromatography. Immunoreactive insulin was also separated into two major bands by standard polyacrylamide gel electrophoresis. The fast migrating band corresponds to the rat insulin II position, and the slower corresponds to rat insulin I, which has one more basic amino acid residue in comparison with rat insulin II. Further studies have been performed in five healthy adults in order to elucidate the physiological relationship between analogs of insulin and C-peptide peak substances in human serum; the results are reported in this paper with a consideration of the mechanism of insulin secretion.

Adult↗
PubMed1984

Ontogeny of immunoreactive somatostatin in thyroid C cells from dogs and guniea pigs.

The development of immunoreactive somatostatin in thyroid C cells of dogs and guinea pigs from early fetuses to adults was investigated by the use of immunoperoxidase histochemistry and radioimmunoassay. The time of appearance and developmental patterns of immunoreactive somatostatin in the C cells were completely different in both species. In guinea pig thyroids, the somatostatin immunoreactivity appeared later than the calcitonin immunoreactivity and the number of somatostatin-positive cells was very small during fetal periods. The somatostatin immunoreactivity rapidly increased during neonatal periods. A large population of the somatostatin cells and a high concentration of somatostatin immunoreactivity were observed in mature animals. On the other hand, in dog fetuses somatostatin immunoreactivity appeared very early, at the same time as the calcitonin immunoreactivity. The largest population of somatostatin cells was found at the stage when the primordial follicles were vigorously formed throughout whole thyroid parenchyma. At this stage almost all of calcitonin-positive cells were also somatostatin-positive. The somatostatin cells progressively decreased as the development proceeded, in contrast to the calcitonin cells which increased with gestational age. In postnatal dogs only a few C cells revealed the immunoreaction for somatostatin, and the concentration of somatostatin was very low. These findings suggest that the function of somatostatin in dog thyroid C cells may be different from that in guinea pig C cells.

Animals↗