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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 613 records · Page 34Linked to original sources
PubMed1989

Radioimmunoassay of inhibin in various mammals.

A sensitive radioimmunoassay (RIA) for the determination of inhibin in peripheral plasma and tissue homogenates of different species has been developed using antisera to partially purified bovine follicular fluid (bFF) inhibin and 125I-labelled bFF 32 kDa inhibin. Antisera were produced by immunization of rabbits with partially purified bFF inhibin prepared by immunoaffinity chromatography. Increasing doses of a high titre antiserum could neutralize the suppressing effect of bFF, porcine follicular fluid and rat ovarian homogenate on FSH secretion from rat anterior pituitary cells in culture. Sensitivity of the assay was 3.1 ng International Research Standard of porcine inhibin per tube. Parallel inhibition curves were obtained for inhibin preparations from female and male animals of ten species, i.e. cattle, goats, sheep, cats, dogs, monkeys, pigs, horses, rats and man. Inhibin subunits and related proteins cross-reacted minimally with the antiserum used in the study. Plasma concentrations of inhibin in adult male and female rats were measured by the RIA before and at various times after gonadectomy. Inhibin levels in peripheral plasma before gonadectomy were significantly higher in adult female than in adult male rats. Inhibin levels decreased abruptly after gonadectomy in both sexes and they correlated negatively with plasma concentrations of FSH. This inhibin RIA will facilitate studies of the physiology of inhibin in various species of animals.

Animals↗
PubMed1989

[Clinical survey on denture stomatitis. 1. Relation between denture plaque and denture stomatitis].

Denture stomatitis is a very frequent complication of the denture wearers. In this study, the relation between denture plaque and denture stomatitis was evaluated by a simplified culture (STOMASTAT). 583 patients wearing dentures (1981-1987) were selected, from 47 to 91 years old. The following results were obtained. 1. Degree of denture plaque in 583 patients was severe, moderate, and no detection: 30, 35 and 35%, respectively. 2. Grade of denture stomatitis in 583 patients was severe, moderate, and no symptom: 24, 36 and 40%, respectively. In this survey, the occurrence of denture stomatitis was about 60%. 3. The good correlation between degree of denture plaque and grade of denture stomatitis was recognized in this study. The present results suggest that denture plaque plays an etiologic role in denture stomatitis and, in daily practice, it is important to instruct denture plaque control for denture wearers.

Aged↗
PubMed1989

Cerebral artery blood flow velocity waveforms in normal and small for dates fetuses.

Middle cerebral artery (MCA) blood flow velocity waveforms were recorded by a pulsed Doppler system in normal and small for dates (SFD) fetuses. Eighty four normal growth fetuses and 15 SFD fetuses were studied between the 28th and 40th gestational week. The flow velocity waveforms were analysed to determine the resistance index (RI = peak systolic velocity minus end diastolic velocity/peak systolic velocity). The results obtained were as follows: 1. The mean values of RI in the MCA had a peak of 0.802 +/- 0.049 at 32-33 gestational weeks and decreased gradually to a level of 0.686 +/- 0.087 at 40 gestational weeks. 2. In 8 asymmetrical SFD fetuses, the RI values for the MCA were below the normal range (mean -1.5 SD) in 6 cases and normal in 2 cases. 3. The RI values for MCA in all 7 symmetrical SFD fetuses were in the normal range.

Blood Flow Velocity↗
PubMed1989

LPS augments adoptive transfer of experimental allergic encephalomyelitis in the Lewis rat.

Adoptive transfer of experimental allergic encephalomyelitis (EAE) is enhanced after in vitro culture of myelin basic protein (BP)-sensitized lymphoid cells with BP. Addition of lipopolysaccharide (LPS) to the culture further augments transfer of EAE to a level 5 times greater than that achieved with cells activated only with BP. Neither the proliferative response of a BP-specific cell line nor the production of IL-2 by BP-sensitized lymphoid cells in response to BP was augmented by the addition of LPS to the culture. Augmentation of EAE was also observed if recipients received simultaneous injections of BP-sensitized lymph node cells (BP/LNC) cultured with BP (BP-activated) and normal spleen cells cultured independently with LPS (LPS/Spl-C). To analyze the effect of contact between these two cell populations in vivo, we mixed the two cell populations in vitro at reduced cell concentrations. When BP-activated BP-LNC were mixed with LPS-Spl-C in vitro, a marked synergistic proliferative response was observed. Irradiation of BP-activated BP/LNC abrogated this synergistic response, whereas irradiation of LPS/Spl-C did not, suggesting that the proliferating population was in the BP/LNC and that the LPS/Spl-C enhanced their proliferation. These results indicate that LPS exerts its effect through BP-nonspecific cells and that these cells enhance transfer of EAE by augmenting the proliferation of the BP-specific cells in vivo after transfer.

Animals↗
PubMed1989

[The role of immunoreactive nerves in the human bladder neck].

VIP-containing nerves have been considered as an inhibitory nerve of non-cholinergic, non-adrenergic action in the bladder neck. Using immunohistochemistry, VIP was stained in the bladder neck in 14 cases which involved 5 cases of bladder neck contracture in addition to 9 cases of benign prostatic hypertrophy (BPH). Consequently, the VIP immunoreactive nerve was not stained in the 4 cases of bladder neck contracture with a large quantity of residual urine which had the fibrosis of bladder neck, but in one case was stained without residual urine. In the BPH, 8 out of 9 cases were stained and they had small residual urine. It was fully stained in the cases without residual urine or with a small volume if they had it. The possible role of VIP in the bladder neck was supposed to be to maintain the bladder neck opening by the strong smooth muscle relaxation.

Aged↗
PubMed1989

[Prevention of renal toxicity of cisplatin by administration of bismuth subnitrate].

The effect of pretreatment with bismuth subnitrate (BSN) for prevention of the renal toxicity of cisplatin (CDDP) was examined in 44 patients with lung cancer (43 non-small cell and one small cell lung cancer). In non-small cell lung cancer cases, the effect of the antitumor activity of chemotherapeutic drugs was observed in 62% of patients pretreated with BSN, and 42% in the group without pretreatment with BSN. No antitumoral activity of chemotherapeutic drugs was suppressed by treatment with BSN. In the group without pretreatment of BSN, serum creatinine and BUN were in proportion to the number of administrations of chemotherapeutic drugs. On the other hand, no renal toxicity was shown in the group with pretreatment by BSN. No protective effect against myelosuppression with pretreatment by BSN was demonstrated, perhaps because of the influence of anti-cancer drugs apart from CDDP.

Adult↗
PubMed1989

Acquired pigmented macules in human piebald lesions. Ultrastructure of melanocytes in hypomelanotic skin.

Two cases of piebaldism are reported. The first patient was a 9-month-old girl with inborn hypopigmented areas on the frontal region of the scalp and both knees. There were no melanocytes in the lesions. In the second case, we observed the patient from 2 months of age for a period of 9 years. Many hyperpigmented spots appeared on the hypomelanotic areas on the frontal region of the scalp, abdomen and both knees. Electron-microscopic examinations of the hypomelanotic skin disclosed an area with regularly distributed melanocytes as well as an area with no melanocytes. Most of the melanosomes were ellipsoidal and lamellar. They were in stage II to III, which signified delayed pigmentation. Hyperpigmented spots were slightly enlarged following PUVA treatment.

Female↗
PubMed1989

[CDDP-ACR treatment in patients with recurrent ovarian cancer with prior chemotherapy containing CDDP--a preliminary study of a 14-day continuous infusion of CDDP with ACR].

Six patients with recurrent ovarian cancer who had prior chemotherapy were studied for the clinical efficacy of CDDP-ACR treatment. Five out of the 6 had received CDDP a total doses of 1,320, 780, 750, 475, and 340 mg. CDDP-ACR therapy consisted of continuous infusion of CDDP at a daily dose of 10 mg/m2 over 14 days (total CDDP doses; 140 mg/m2) and of intermittent infusion of ACR (aclarubicin) at a dose of 20 mg/body every other day (total ACR doses: 140 mg). There were one CR and five PR and a response rate up to 100% was noted. Toxicity was manifested in slight nausea or vomiting, but there was no nephrotoxicity. However bone marrow was severe. Thrombocytopenia less than 50,000/mcl in 4 pts (67%) and leukopenia less than 1,000 mcl in 3 pts (50%). The mean filterable platinum exposure measured by area under the concentration-time curve (AUC) was as high as 19.7 +/- 6/0 mg.hr/ml. In conclusion the bone marrow toxicity in this regimen was severe, but the therapeutic efficacy was promising. Further studies on the appropriate infusion time and the minimum effective dose of CDDP are needed.

Abdominal Neoplasms↗
PubMed1989

Distal surface of the rat ruffle-ended ameloblasts at the stage of enamel maturation observed by scanning electron microscopy.

Distal surface of the rat ruffle-ended ameloblasts was observed by high resolution scanning electron microscopy. Specimens fixed by perfusion with 0.5% formaldehyde and 0.5% glutaraldehyde were decalcified with ethylenediamine tetraacetic acid and freeze-fractured using dimethyl sulfoxide. They were treated with 0.1% osmium tetroxide for 96 hr to remove excess cytoplasmic matrices, dehydrated, and critical-point dried. The present method was useful for observing both surface and intracellular structures simultaneously. The dense lamina lining the distal surface of the ruffle-ended ameloblasts having been dissolved in this preparation, the surface was clearly demonstrated in three dimensions under SEM. The surface was characterized by a complex labyrinth formed by protrusion and invagination of the plasma membrane. At high magnification, two kinds of minute granules are visible: small and larger granules measured as 10-20 nm and 70 nm in diameter, respectively. The former were more numerous than the latter. Furthermore, microfibrils connecting the protrusions of the plasma membrane were observed on the distal surface. The small granules probably connect the dense lamina with the distal surface of the ameloblasts. In addition, a denuded area free from the granules was sometimes recognized on the distal surface. These surface structures of the distal end of the ameloblasts appeared to be concerned with the enamel maturation.

Ameloblasts↗
PubMed1989

[A case of renal leiomyoma with remarkable calcification].

A case of renal leiomyoma with remarkable calcification is reported. The patient is a 46-year-old female. The tumor is 9 x 10 x 12 cm in size and is occupied by granular minute calcifications. Angiographically segmental arteries are stretched by a tumor, in which there are minute tumor vessels and inhomogeneous tumor stain.

Calcinosis↗
PubMed1989

[Microcystic adnexal carcinoma--a light and electron microscopic studies].

Microcystic adnexal carcinoma (MAC) in a 48-year-old Japanese male was studied. A firm nodule had appeared on the right side of his upper lip at the age of 38 years and then had gradually enlarged. Light microscopic examinations revealed numerous strands and islands of basaloid cells and keratinous cysts with desmoplastic stroma in the dermis and subcutaneous tissue. Some keratinous cysts showed early calcification and some contained pilar structures. Clear cells resembling sebaceous gland cells were observed in the strands of tumor cells connecting the keratinous cysts. In the middle dermis, there were small ductal structures containing amorphous eosinophilic material. Immunoperoxidase staining for carcinoembryonic antigen was focally positive in the lumina of small ducts, on the ductal lining surface of tumor cells, and in the contents of keratinous cysts. Electron microscopic examinations revealed tumor cells resembling non-keratotic keratinocytes, and containing tonofilaments, mitochondria, and vacuoles. In some parts, tumors were differentiated to various types of sebaceous gland, sweat duct, or sweat secretary segments. Sebaceous gland cells contained lipid droplets and glycogen. Tumors differentiated to sweat duct had a marked similarity to embryo eccrine duct in the lower epidermis because of the presence of multivesicular dense bodies and periluminal filamentous zones and the absence of myoepithelial cells. Tumors differentiated to sweat secretary segments had a similarity to embryo eccrine secretary segments because of the absence of multivesicular dense bodies, periluminal filamentous zones and myoepithelial cells.

Carcinoma↗