Search PubMed⌕ Search

Biomedical subjects

Y Shishiba

Publications and source records attributed to Y Shishiba.

At least 55 records · Page 3Linked to original sources
PubMed1992

Disseminated cryptococcosis presenting with adrenal insufficiency and meningitis: resistant to prolonged antifungal therapy but responding to bilateral adrenalectomy.

A case of disseminated cryptococcosis with features of primary adrenal insufficiency and meningitis in an immunocompetent host is presented. Despite antifungal chemotherapy, neither meningitis nor bilateral adrenal gland enlargement was improved. Aspiration biopsy of the adrenal gland revealed necrotic tissue with numerous fungi, suggesting that the adrenal glands were the focus of the persistent fungemia. Removal of bilateral adrenal glands led to improvement by making the patient more sensitive to antifungal chemotherapy.

Adrenal Gland Diseases↗
PubMed1991

Gonadotroph adenoma of the pituitary mimicking a prolactinoma.

In a 41-year-old woman with mild hyperprolactinemia and amenorrhea, preoperative hormonal and neuroradiological findings suggested the diagnosis of a macroprolactinoma. She underwent transsphenoidal surgery since the tumor size had not changed in spite of bromocriptine administration for 5 months. Consequently, this case was diagnosed as a female-type gonadotroph adenoma on the basis of its characteristic ultrastructural features including a honeycomb Golgi complex, even though endocrinological and immunohistochemical findings were not those of a typical gonadotroph adenoma.

Adenoma↗
PubMed1991

Paradoxical prolactin response to growth hormone-releasing hormone in a patient with hyperprolactinemia and empty sella.

In a 30-year-old woman with amenorrhea due to hyperprolactinemia, serum PRL increased to twice the basal amount in response to growth hormone-releasing hormone (GHRH). Roentgenological studies revealed no pituitary adenoma but empty sella. Bromocriptine therapy normalized serum PRL and made the paradoxical response to GHRH disappear. The paradoxical response did not occur in any of eight other patients with hyperprolactinemia due to prolactinoma. Although this case is rare, GHRH stimulates PRL as well as GH release remarkably in some cases with hyperprolactinemia without a GH-producing tumor.

Adult↗
PubMed1990

Isolation and characterization of proteoglycans synthesized by mouse osteoblastic cells in culture during the mineralization process.

Proteoglycans in mineralized (0.5 M-EDTA/4 M-guanidinium chloride-extractable) and non-mineralized (4 M-guanidinium chloride-extractable) matrices synthesized by a mouse osteoblastic-cell line MC3T3-E1 were characterized at different phases of mineralization in vitro. Cell cultures were labelled with [35S]sulphate and either [3H]glucosamine or 3H-labelled amino acids. At the mineralization phase a large majority of proteoglycans were extracted with 4 M-guanidinium chloride (G extract), and at least five species of labelled proteoglycans were identified; dermatan sulphate proteoglycans (DSPG), apparent Mr approx. 120,000 and 70,000), heparan sulphate proteoglycans (HSPG, apparent Mr approx. 200,000 and 120,000) and DS chains with very little core protein. DSPGs weakly bound to an octyl-Sepharose CL-4B column and HSPGs bound more tightly, whereas DS chains did not bind to the column. Amounts of labelled proteoglycans extracted with 0.5 M-EDTA/4 M-guanidinium chloride (EDTA extract) were much less than those in G extract. Although the predominant species in the EDTA extract were comparable with the DS or DSPGs in the G extract, none of them bound to octyl-Sepharose CL-4B, indicating their lack of hydrophobicity. At the nonmineralizing phase a large chondroitin sulphate proteoglycan (Mr greater than 600,000) was found in the matrix in addition to the five proteoglycan species similar to those at the mineralization phase. Although DS chains at the early phase were similar in size to those at the mineralization phase, the ratio of 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulpho-D-galactose to 2-acetamido-2-deoxy-3-O-(beta-D-gluculo-4-enepyranosyluronic acid)-6-O-sulpho-D-galactose was less than that at the mineralization phase. These results agree with those of previous studies performed in vivo and suggest that alteration in the synthesis of proteoglycans is involved in the mineralization process. They also suggest that at the osteoblastic mineralization front proteoglycans undergo partial degradation and lose their hydrophobicity.

Animals↗
PubMed1990

Hyperparathyroidism associated with Cushing's syndrome due to an adrenal cortical adenoma.

Two patients with the rare association of Cushing's syndrome and primary hyperparathyroidism are reported. Initially, both patients suffered from Cushing's syndrome due to adrenal cortical adenomas with typical features and laboratory findings. Five years after treatment of the Cushing's syndrome by removal of the tumor, asymptomatic mild hypercalcemia was incidentally noticed in both patients, which suggested the occurrence of primary hyperparathyroidism. An enlarged parathyroid gland was removed surgically in both cases and was histologically shown to be a parathyroid adenoma. The levels of serum calcium returned to normal after parathyroidectomy. Papillary adenocarcinoma of the thyroid in one patient and adenomatous goiter in the other were also incidentally detected at operation. These findings suggest that Cushing's syndrome resulting from an adrenal cortical adenoma may be another presentation of multiple endocrine neoplasia type I.

Adenoma↗
PubMed1990

Serum hyaluronan concentration determined by radiometric assay in patients with pretibial myxedema and Graves' ophthalmopathy.

The serum concentration of hyaluronan (HA) was measured by radiometric assay in patients with pretibial myxedema (PTM) and Graves' ophthalmopathy (GO). The mean HA concentration in the patients (n = 8) was 21.2 +/- 15.3 (mean +/- SD) microgram/l, while that of Graves' disease without skin or eye involvement (n = 7) was 23.5 +/- 11.0 (mean +/- SD) microgram/l and that of the control (n = 8) was 25.5 +/- 16.4 (mean +/- SD) microgram/l. We conclude that local accumulation of glycosaminoglycan in PTM or GO is not associated with an increase in the serum HA concentration.

Adult↗
PubMed1990

Thyroid hormone excess stimulates the synthesis of proteoglycan in human skin fibroblasts in culture.

We previously demonstrated that proteoglycan accumulated in the affected skin of circumscribed pretibial myxedema of Graves' disease. As an underlying mechanism responsible for the accumulation, we sought to determine whether excess thyroid hormone was partially responsible for the increase in proteoglycan synthesis. Human skin fibroblasts were cultured in Ham's F-10 medium containing 1% Nutridoma with graded doses of T3 (0.184 x 10(-9) to 46 x 10(-9) mol/l) and were labelled with [35S]sulphate and [3H]glucosamine. Proteoglycans were purified by Sephadex G-50, Q-Sepharose chromatography with NaCl-gradient and Sepharose CL-6B chromatography. 35S and 3H incorporated into dermatan sulphate proteoglycan and heparan sulphate proteoglycan and 3H incorporated into hyaluronan were measured. 35S and 3H incorporation into dermatan sulphate proteoglycan was minimum at a T3 concentration of 0.184 x 10(-9) mol/l, and increased with increasing doses of T3 up to 46 x 10(-9) mol/l. 35S and 3H incorporation into heparan sulphate proteoglycan also increased with increasing-doses of T3. 3H incorporation into hyaluronan was not influenced at all by T3. The increased incorporation of 35S into proteoglycan in high-T3 culture reflects the increased synthesis of proteoglycan because 1. the extent of sulphation of disaccharides examined by thin-layer chromatography was not altered by T3; 2. the specific activity of [35S]sulphate was not influenced by T3, and 3. T3 did not decrease the degradation rate of cell-associated proteoglycan.

Adolescent↗
PubMed1989

1,25-Dihydroxyvitamin D3 inhibits synthesis and enhances degradation of proteoglycans in osteoblastic cells.

The effects of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), an active form of vitamin D3, on the metabolism of proteoglycans by an osteoblastic cell line MC3T3-E1 were studied. Cells metabolically labeled with [35S]sulfate and/or [3H]glucosamine synthesized large and small dermatan sulfate proteoglycans and heparan sulfate proteoglycan. The incorporation of [35S]sulfate into proteoglycans for 1 h was reduced by 1,25-(OH)2D3 in a dose-dependent manner with a maximum reduction of 40% obtained at 10(-8)M 1,25-(OH)2D3. This effect was observed for all the proteoglycans with the decrease for the large dermatan sulfate proteoglycan most prominent. Treatment with 1,25-(OH)2D3 did not influence the degree of sulfation nor the molecular size of the glycosaminoglycan chains. Thus, the change in the incorporation of [35S] sulfate reflects net change in the synthesis of proteoglycans. When cells were treated with beta-D-xyloside, 1,25-(OH)2D3 also inhibited net synthesis of dermatan sulfate glycosaminoglycan chains on this exogenous substrate suggesting that it decreases the capacity of the cells for glycosaminoglycan synthesis. The incorporation of [3H]glucosamine into hyaluronic acid was also inhibited up to 70% by 10(-8) M 1,25-(OH)2D3. Treatment with 24,25-dihydroxyvitamin D3 did not cause significant changes in the proteoglycan synthesis. Degradation of proteoglycans associated with the cell layer was enhanced by treatment with 1,25-(OH)2D3 at 10(-8) M. Proteoglycans exogenously added to the culture were also degraded with a cell-mediated process which was stimulated by treatment with 10(-8) M 1,25-(OH)2D3. These results demonstrate that 1,25-(OH)2D3 reduces the synthesis and stimulates the degradation of proteoglycans in osteoblastic cells in culture.

24,25-Dihydroxyvitamin D 3↗
PubMed1989

Postoperative prognostic indicators of control of acromegaly.

Changes in growth hormone basal levels and growth hormone dynamic tests such as thyrotropin-releasing hormone and luteinizing hormone-releasing hormone tests, and the glucose tolerance test were evaluated during a follow-up period of 1-17 years in 17 acromegalic patients. In these cases, mean growth hormone basal levels obtained 1-2 months after surgery had dropped to levels below 5 ng/mL. In 11 of the patients, the 1-2 months postoperative mean growth hormone basal levels were reduced to less than 3 ng/mL. In these patients, abnormal growth hormone responses to these dynamic tests were not present and mean growth hormone basal levels remained below 3.0 ng/mL during the follow-up period of 1-6 years. In contrast, the six other patients' 1-2 months postoperative mean growth hormone basal levels were between 3 and 5 ng/mL. Of these, four presented abnormal responses in at least one of these three dynamic tests 1-2 months postoperatively, and three exhibited a rise in growth hormone basal levels after intervals of 1-3.5 years after surgery. It is concluded that the restoration of normal growth hormone response to the dynamic tests is better related to the value of the mean growth hormone basal levels obtained 1-2 months postoperatively being less than 3 ng/mL rather than it is to the conventional criterion of the growth hormone basal levels being less than 5 ng/mL.

Acromegaly↗
PubMed1989

Heterogeneity of big-big hPRL in hyperprolactinemia.

Sera from a patient with macroprolactinoma (case 1) and from a hyperprolactinemic woman with regular menstruation (case 2) were analyzed for prolactin activity by gel filtration using Sephadex G-100, Sephadex G-200 and TSK G3000SW columns. The chromatographic profile by Sephadex G-100 showed that the percentage of immunoreactive big-big hPRL was 10.7% in case 1 and 64.1% in case 2. On Sephadex G-200 and TSK G3000SW columns, the molecular weight of big-big hPRL was estimated to be more than 500,000 daltons (big-big1 hPRL) in case 1 and approximately 250,000-300,000 daltons (big-big2 hPRL) in case 2. Big-big1 hPRL in case 1 was converted to big and little hPRLs when the serum was treated with 2-mercaptoethanol (2-ME), but part of the big-big2 hPRL in case 2 was converted to a larger molecule. Radioactive big-big hPRL generated by mixing labeled hPRL with the serum from case 1 was eluted with the void volume on Sephadex G-100 column and was not converted to the other molecular forms after 2-ME treatment. There were two radioactive big-big hPRL on TSK G3000SW column and these estimated molecular weights were more than 300,000 daltons. The data demonstrated the existence of at least two forms of big-big hPRL in the serum and indicated that radioactive big-big hPRL may be different from these hPRLs in the serum.

Chromatography, Gas↗
PubMed1989

Bioactivity of human growth hormone in urine from acromegalic patients.

Bioactivity of hGH in urine from five acromegalic patients was determined by Nb2 bioassay and IM-9 receptor modulation assay (RMA). Urine samples were concentrated by immunoadsorbent chromatography, dialysis and lyophilization. The ratio of the bioactivity by Im-9 RMA and the immunoactivity by RIA was between 0.81 and 1.24 (1.01 +/- 0.19, mean +/- SD). The ratio of the bioactivity by Nb2 bioassay and the immunoactivity ranged from 0.45 to 0.60 (1.37 +/- 0.85). Gel chromatography of hGH in urine samples measured by sensitive sandwich enzyme immunoassay showed that more than 97% of hGH activity was the 22K form. Urinary hGH from acromegalic patients was bioactive in Nb2 bioassay and IM-9 RMA and the bioactivity showed a close correlation with the immunoactivity. The major immunoactive form of hGH (22K) seems to correspond to the bioactivity.

Acromegaly↗
PubMed1989

ACTH determination in a petrosal sinus venous specimen after corticotrophin releasing factor provides the best clue on the laterality of microadenoma in Cushing's disease.

A 42-year-old woman with Cushing's disease was endocrinologically cured after transsphenoidal selective excision of a left-sided microadenoma. Simultaneous samplings from the bilateral inferior petrosal sinuses with ovine corticotrophin-releasing factor (CRF) stimulation were performed preoperatively to evaluate some relations between the localization of a possible microadenoma and the levels of ACTH in inferior petrosal sinuses. The data for the venous samplings were as follows:-(1) The basal levels of ACTH obtained simultaneously from both inferior petrosal sinuses and peripheral vein were about the same. (2) A significant difference, with a high level of ACTH from the ipsilateral side of the microadenoma, was demonstrated after CRF stimulation. (3) The magnitude of increase in ACTH on the contralateral side after CRF was similar to that of the peripheral response. It is recommended that all patients with ACTH dependent Cushing's syndrome and negative radiological findings should have bilateral simultaneous inferior petrosal venous sampling with CRF stimulation.

Adenoma↗
PubMed1988

[Bioactivity and heterogeneity of human growth hormone in urine from acromegalic patients].

Bioactivity of hGH in urine from five acromegalic patients was determined by Nb2 rat lymphoma bioassay (Nb2BA) and IM-9 receptor modulation assay (RMA). One urine sample (case 1) was concentrated by dialysis and lyophilization. Bioactivity by IM-9 RMA showed close correlations with immunoactivity by RIA in serial dilutions (RMA/RIA; 0.66-1.77). The estimates of bioactivity by Nb2BA were higher in all diluted samples except undiluted one than those of immunoactivity. Four samples were concentrated by affinity chromatography, dialysis and lyophilization. The ratio of RMA and RIA estimates was between 0.81-1.24, and that of Nb2BA and RIA estimates was between 0.46-2.62. Heterogeneity of urinary hGH was analyzed by gelfiltration using TSK-G-3000SW column by high performance liquid chromatography (HPLC) and by sensitive sandwich enzyme immunoassay. In addition to the main peak of 22K molecular weight (more than 97%), very small peaks of 40-60K (big hGH) and 150K (big-big hGH) were detected in chromatographic profile. Urinary hGH from acromegalic patients was bioactive in IM-9 RMA and Nb2BA. The predominant form of urinary hGH from acromegalic patients was little hGH, but big and big-big hGH were detected by sensitive sandwich enzyme immunoassay.

Acromegaly↗
PubMed1988

Characterization of proteoglycans synthesized by rat thyroid cells in culture and their response to thyroid-stimulating hormone.

A Fisher rat thyroid cell line was maintained in culture and the cells were labeled with [3H]glucosamine, [35S]sulfate, and [35S]cysteine to examine the synthesis of proteoglycans. 3H and 35S radioactivity from these precursors were incorporated into both chondroitin sulfate (CS) and heparan sulfate (HS) proteoglycans. CS proteoglycans were almost exclusively secreted into the medium while HS proteoglycans remained mainly associated with the cell layer. Single chain glycosaminoglycans released by papain digestion or alkaline borohydride treatment of either the CS or HS proteoglycans had average molecular weights of approximately 30,000 on Sepharose CL-6B chromatography. Both CS and HS proteoglycans were relatively small and contained only one or two glycosaminoglycans chains. 3H and 35S incorporation into both CS and HS proteoglycans were increased by thyroid-stimulating hormone (TSH) in a dose-dependent manner, which is in part explained by an adenylate cyclase-dependent mechanism as indicated by a similar effect in response to dibutyryl cAMP. TSH enhanced the incorporation of 35S into CS from [35S]cysteine about 1.5-fold and that from [35S]sulfate about 2-fold. This result demonstrated that the increased 35S incorporation from the [35S]sulfate precursor reflects an actual increase in sulfate incorporation and is not simply a result from an apparent increase in specific activity of the phosphoadenosine phosphosulfate donor. Analysis of disaccharides from chondroitinase digests revealed that the proportion of non-sulfated, 4-sulfated, and 6-sulfated disaccharides was not altered appreciably by TSH. These results, together with the disproportionate increase in 3H incorporation into CS from [3H]glucosamine, indicated that TSH increased the specific activity of the 3H label as well. Chase experiments revealed that CS proteoglycans were rapidly (t1/2 = 15 min) secreted into the medium and that the degradation of cell-associated proteoglycans was enhanced by TSH.

Animals↗
PubMed1988

Effect of thyroid hormone deficiency on proteoglycan synthesis by human skin fibroblast cultures.

Proteoglycans and hyaluronic acid synthesized by human skin fibroblasts in culture were characterized, and the effect of thyroid hormone deficiency was examined. The fibroblasts in culture synthesize hyaluronic acid, dermatan sulfate (DS) proteoglycans and heparan sulfate (HS) proteoglycans. Hyaluronic acid is almost exclusively secreted into the medium. Among the proteoglycans synthesized during 24 h label, about 70% were secreted into the medium and the remaining 30% were associated with the cell layer. About 70% of proteoglycans secreted into the medium contained DS and the remaining 30% contained HS. For cell-associated proteoglycans, 60% contained HS and the remainder contained DS. The size distributions of the glycosaminoglycans from both DS and HS proteoglycans were similar, with an average Mr of approximately 30,000. Incubation of fibroblasts in thyroid hormone deficient medium increased net synthesis of hyaluronic acid (approximately 50%) and all species of proteoglycans (approximately 85%). 3H/35S ratios in the chondroitin 4-sulfate disaccharide isolated with HPLC were not altered in thyroid hormone deficient cultures, indicating that the specific activity of 3H in UDP-N-acetylhexosamine precursors did not change. The increased incorporation of 3H into hyaluronic acid and of 3H and 35S into DS and HS proteoglycans thus indicates increased net synthesis. Degradation of cell-associated proteoglycans was not influenced by thyroid hormone deficiency.

Adolescent↗
PubMed1988

Heterogeneity of the immune status concerning anti-thyroglobulin antibody production among patients with Hashimoto's thyroiditis; an in vitro study.

In vitro anti-thyroglobulin antibody (TgAb) production by unstimulated, thyroglobulin (Tg)-stimulated and pokeweed mitogen (PWM)-stimulated peripheral blood lymphocytes (PBL) from 44 patients with Hashimoto's thyroiditis and 10 normal individuals was investigated using a biotin-avidin enzyme-linked immunosorbent assay. Spontaneous TgAb production by non-T cells alone was observed in some patients. TgAb production induced by Tg was T cell-dependent and not accompanied by nonspecific IgG production. PBL from normal individuals produced no TgAb under any conditions. The patients were divided into four groups: 24 showed no TgAb production under any conditions, eight showed TgAb production only with PWM, seven produced TgAb spontaneously and more with both Tg and PWM, and five showed spontaneous TgAb production but no increase with Tg (four of these five patients showed an increase with PWM). Significant positive correlations between the serum TgAb titre and the amounts of TgAb produced by unstimulated, and Tg-stimulated and PWM-stimulated PBL were observed. It was suggested that spontaneous TgAb production was due to in vivo triggered antibody-producing B cells, while the TgAb produced only after in vitro Tg stimulation would be due to Tg-specific memory B cells helped by Tg-specific T cells. The increase in TgAb production due to PWM may be caused by activation of nonspecific helper T cells. These different PBL profiles probably reflect the heterogeneity of the immune status concerning TgAb production among patients with Hashimoto's thyroiditis.

Adult↗