Biomedical subjects

N Itoh

Publications and source records attributed to N Itoh.

643 records · Page 36Linked to original sources

PubMedDate not supplied

Human preprovasoactive intestinal polypeptide contains a novel PHI-27-like peptide, PHM-27.

Vasoactive intestinal polypeptide (VIP), a 28-amino acid peptide originally isolated from porcine duodenum, is present not only in gastrointestinal tissues but also in neural tissues, possibly as a neurotransmitter, and exhibits a wide range of biological actions (for example, relaxation of smooth muscle, stimulation of intestinal water and electrolyte secretion and release of insulin, glucagon and several anterior pituitary hormones). As the structure of porcine and bovine VIP shows several similarities to those of mammalian glucagon, secretin and gastric inhibitory peptide (GIP), VIP is considered to be a member of the glucagon-secretin family. Recently, we have found that VIP is synthesized from a precursor, pro-VIP (molecular weight (Mr) 17,500), in human neuroblastoma cells and that the primary translation product of the mRNA encoding VIP is prepro-VIP (Mr 20,000). In an attempt to elucidate the primary structure of the precursor, we have now cloned the DNA sequence complementary to the mRNA coding for human VIP and analysed the nucleotide sequence. The entire amino acid sequence of the precursor, deduced from the nucleotide sequence, indicates that the precursor protein contains not only VIP but also a novel peptide of 27 amino acids. The peptide, designated PHM-27, differs by only 2 amino acids from PHI-27, a peptide recently isolated from porcine intestine, and is also closely related in sequence to VIP.

Amino Acid Sequence↗

PubMedDate not supplied

Outcome analysis of sildenafil citrate for erectile dysfunction of Japanese patients.

The approved maximal dose of sildenafil is only 50 mg in Japan, but the impact of dose regulation on treatment outcomes has not been established. Moreover, the contributors to the efficacy in patients having an intact peripheral nervous system have not been fully elucidated. We assessed in Japanese patients the treatment outcomes of sildenafil for erectile dysfunction (ED) under regulation of the approved dose and identified factors contributing to its efficacy among those with various etiologies other than pelvic surgery. We retrospectively reviewed 196 ED patients treated with sildenafil. The overall efficacy was 70.9% (139/196), and patients with psychological problems and concomitant cardiovascular disease showed high response rates (82.4 and 87.0%, respectively). Of the 139 responders, 89.9% achieved efficacy with a dose of 25 or 50 mg. Logistic regression analysis revealed concomitant cardiovascular disease and a favorable nocturnal penile tumescence result to be independent contributors to the efficacy.

Adult↗

PubMedDate not supplied

An autopsy case of cerebellar degeneration following lithium intoxication with neuroleptic malignant syndrome.

We report a rare case of cerebellar degeneration that was diagnosed at autopsy in a patient who developed lithium intoxication accompanied by neuroleptic malignant syndrome. This 63 year old female, who suffered from manic depressive psychosis, had received lithium bicarbonate at a daily dose of about 1000 mg for 4 years. She developed a high fever and extrapyramidal symptoms resembling a neuroleptic type of malignant syndrome and died 1 month later. Autopsy revealed an almost complete loss of Purkinje cells with a mild reduction of granule cells in most areas of the cerebellar hemisphere and vermis, except for the tonsil and flocculus, and mild gliosis in the dentate nucleus. In cases of suspected lithium intoxication, one must be alert to the possibility of neuroleptic malignant syndrome and to prevent cerebellar degeneration.

Bipolar Disorder↗

PubMedDate not supplied

An autopsy case of pulmonary artery leiomyosarcoma.

A case of pulmonary artery leiomyosarcoma in a 37 year old Japanese man is reported. The patient complained of chest pain and hemosputum. CT scan and angiography revealed that a tumor arose from the right main branch of the pulmonary artery. The surgical specimen was interpreted as an undifferentiated sarcoma at this time. The tumor recurred 6 months after the resection, and he died of right-sided heart failure. At autopsy, the pulmonary artery truncus was distended by the tumor, which protruded into the lumen. The tumor was composed of pleomorphic cells, giant cells and spindle-shaped cells. Many of the tumor cells were immunohistochemically positive for alpha-smooth muscle actin and vimentin. Electron microscopy revealed microfilaments with dense bodies in the cytoplasm and a discontinuous basement membrane around the cells. Although adenocarcinoma was also observed in the colon, the authors conclude that the present tumor is not a metastasis but a primary leiomyosarcoma arising from the pulmonary artery. Imaging techniques were very useful for differentiating sarcoma from thrombus in this site, and immunohistochemical demonstration for alpha-smooth muscle actin was necessary for making a histological diagnosis of leiomyosarcoma.

Actins↗

PubMedDate not supplied

Sjögren's syndrome following gastrectomy and chemotherapy for gastric malignant lymphoma.

The case of a 72-year-old man who developed Sjögren's syndrome three years following gastrectomy and chemotherapy for gastric malignant lymphoma is reported. The patient eventually died of systemic cryptococcal infection, and autopsy revealed no recurrence of the malignant lymphoma. Review of the literature indicates lymphoproliferative disease preceding the development of Sjögren's syndrome is extremely rare.

Aged↗

PubMedDate not supplied

Retroperitoneal cellular schwannoma: report of a case diagnosed by the presence of S-100 protein.

A case of cellular schwannoma originating from the retroperitoneum is reported. The histological features of the tumor resembled those of a smooth muscle tumor. However, the tumor cells were positive for S-100 protein, which is almost exclusively identified within nerve sheath tumor cells. This finding confirmed the diagnosis of cellular schwannoma. This type of tumor is generally considered to be benign but is sometimes mistaken for a malignant tumor. These findings indicate that it is important to prove whether or not S-100 protein is present in the cells of a tumor of unknown origin especially arising in the mediastinum or retroperitoneum.

Adult↗

PubMedDate not supplied

Restoration of testicular transferrin, insulin-like growth factor-1 (IGF-1), and spermatogenesis by exogenously administered purified FSH and testosterone in medically hypophysectomized rats.

To investigate the relation between testicular transferrin and insulin-like growth factor-1 (IGF-1) secreted by Sertoli cells and the differentiation of germ cells in the rat, testosterone and/or purified FSH was administered to rats medically hypophysectomized by an LH-RH agonist. Spermatogenesis was quantitatively analyzed and concentrations of intratesticular transferrin and IGF-1 were measured by radioimmunoassays. The last step of spermatogenesis was quantitatively restored by combined administration of testosterone and purified FSH. Intratesticular IGF-1 concentrations were significantly increased by combined administration of testosterone and purified FSH. From these observations, it is surmised that IGF-1 may have a stimulatory effect on the last step of spermatogenesis.

Animals↗

PubMedDate not supplied

Have sperm counts deteriorated over the past 20 years in healthy, young Japanese men? Results from the Sapporo area.

Changes in semen quality of healthy men is a controversial issue throughout the world. It is suspected that many chemical endocrine disrupters may affect the quality of semen. Although exposure to them may be extensive in Japan, no evidence of changes in semen quality has been reported. In this study, changes in semen volume and sperm counts were analyzed over 20 years in the Sapporo area of Japan. Semen volume and sperm counts were measured in 254 and 457 normal, healthy volunteers who lived in the Sapporo area in 1975-1980 and 1998, respectively. Posters and handbills were used to recruit participants in both studies. Semen samples were collected by masturbation after 3 days or more of abstinence. There was no change in semen volume between 1975-1980 and 1998. Mean sperm counts were 70.9 +/- 47.3 x 10(6)/mL in 1975-1980 and 79.6 +/- 49.3 x 10(6)/mL in 1998. Sperm counts did not decline over about 20 years. No significant correlation between age and sperm counts was recognized in either study. The rates of subjects with oligozoospermia and azoospermia were the same in both studies. In the 1975-1980 study, 34 of 254 (13.4%) participants had a child, and in the 1998 study, 51 of 457 (11.2%) participants had a child. Mean sperm count was significantly (P < .02) lower in the earlier study (66.0 +/- 44.9 x 106/mL) than in the 1998 study (98.7 +/- 60.2 x 10(6)/mL). This is the first reliable report in which changes in sperm counts in Japan were studied. We conclude that there was no evidence of deterioration in sperm counts of normal healthy men who lived in the Sapporo area of Japan over 20 years. However, selection bias in the recruitment of volunteers and the issue of variable abstinence might have affected the results of these studies. Therefore, well-designed prospective studies should be performed in several different regions to extrapolate our results on sperm counts to healthy, young Japanese men in general. Key words: Fertility, endocrine disruptors, seminalysis.

Adolescent↗

PubMedDate not supplied

Hepatocellular carcinoma associated with hemophagocytic syndrome.

Hepatocellular carcinoma may manifest various paraneoplastic syndromes. There are some reports describing hematological change due to hepatocellular carcinoma. However, there have been no reports on hepatocellular carcinoma accompanied by hemophagocytic syndrome. We report here for the first time a 51-year-old man with a liver tumor and pancytopenia. Since the patient had showed a strong hemorrhagic diathesis because of thrombocytopenia, we treated him with blood transfusion, but there was no response. Thereafter, we administered the anticancer agents thinking that the hematological change was due to the liver tumor. Though a slight curative effect was obtained, we had to discontinue the treatment because the patient complained of severe side effects. Finally, the patient died of acute cholangitis. Although we could not determine the cause of the pancytopenia before he died, autopsy findings indicated that hemophagocytic syndrome had occurred. Hemophagocytic syndrome related to a solid tumor very rarely occurs. However, when malignant tumor is accompanied by pancytopenia, hemophagocytic syndrome should be considered.

Bone Marrow↗

PubMedDate not supplied

Enhancement by dimethyl sulfoxide of 1,25-dihydroxyvitamin D3-induced differentiation in human promyelocytic HL-60 leukemia cells requires dimethyl sulfoxide-induced G0/G1 arrest.

We investigated the induction of differentiation in human promyelocytic HL-60 leukemia cells by a relatively low concentration of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). The cells were markedly induced to differentiate by combined treatment with reduced concentrations of dimethyl sulfoxide (DMSO) and 1,25(OH)2D3, neither of which alone had much of an effect on differentiation. At 48 hr post-treatment, a greater proportion of DMSO- and DMSO/1,25(OH)2D3-treated, but not 1,25(OH)2D3-treated, cells were in G0/G1 than untreated cells. Our study indicates that the synergistic effect of DMSO and 1,25(OH)2D3 on the induction of differentiation in HL-60 cells requires DMSO-induced G0/G1 arrest.

Calcitriol↗

PubMedDate not supplied

Changes in the endocrinological milieu after clomiphene citrate treatment for oligozoospermia: the clinical significance of the estradiol/testosterone ratio as a prognostic value.

We have already reported that the rate of increase in the estradiol/testosterone ratio (E2/T ratio) following human chorionic gonadotropin (hCG) injection has prognostic value in the treatment of oligozoospermia. It was found that the rate of increase in the E2/T ratio was statistically greater in the therapeutically ineffective cases compared to the therapeutically effective cases. The present study was planned in order to elucidate the relationship between the changes in the endocrinological milieu, especially the change in the E2/T ratio, and the therapeutic efficacy when clomiphene citrate was administered. Thirty-eight oligozoospermic patients were administered 25 mg of clomiphene citrate daily for 3 months. Sixteen of the 38 (42.1%) cases showed improvement of more than 10 x 10(6)/ml in sperm concentration. The rate of increase in the E2/T ratio of the effective cases (0.90 +/- 0.43) during the administration of clomiphene citrate was statistically (P = 0.02) lower than that of the ineffective cases (1.44 +/- 0.80). The rate of increase in the E2/T ratio during clomiphene citrate treatment showed a statistically positive correlation (r = 0.542) with the rate of increase following hCG injection performed before clomiphene citrate treatment. The rate of increase in follicle-stimulating hormone (FSH) in the ineffective cases (2.16 +/- 1.01) was statistically higher than in the effective cases (1.50 +/- 0.43).(ABSTRACT TRUNCATED AT 250 WORDS)

Chorionic Gonadotropin↗

PubMedDate not supplied

Hypertensive changes in intratesticular arteries impair spermatogenesis of the stroke-prone spontaneously hypertensive rat.

It is reported that some elderly males exhibit both hypospermatogenesis and intratesticular arterial changes. These arterial changes are thought to contribute to spermatogenic damage. In this study the process of the damage to spermatogenesis induced by such changes was evaluated using stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP showed a rapid increase of blood pressure, followed by hypertensive vascular changes. At 23 weeks of age, 61.8% of seminiferous tubules were atrophic in SHRSP, simultaneously with the development of hypertensive vascular changes. In addition, the transferrin concentration in the cytosolic fraction of the testicular homogenate was decreased at 23 weeks of age exactly when the severe damage to the spermatogenesis was seen, suggesting that Sertoli cell function in SHRSP regressed at 23 weeks of age. Based on these findings, it was suggested that the decline in the Sertoli cell function caused by the hypertensive vascular changes is part of the mechanism whereby spermatogenic damage occurs in SHRSP.

Animals↗

PubMedDate not supplied

Manidipine improves spermatogenesis in the stroke-prone spontaneously hypertensive rat.

We evaluated the protective effects of manidipine, which is a long-lasting calcium-channel blocker, against damage to spermatogenesis arising from hypertensive vascular changes in stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP showed severe hypertension at 11 weeks of age, followed by hypertensive changes in intratesticular arterioles from 15 weeks of age. Manidipine lowered the blood pressure and the hypertensive vascular changes of intratesticular arterioles in SHRSP. The percentages of atrophic seminiferous tubules and tubules with less-differentiated germ cells were increased in SHRSP at 23 weeks of age, although the administration of manidipine preserved spermatogenesis at a normal level. The transferrin concentration in testicular cytosol was comparable, whereas insulin-like growth factor-I (IGF-I) was reduced from 19 weeks of age in SHRSP. Manidipine preserved the normal IGF-I concentration. Therefore, manidipine prevented the development of hypertensive vascular changes in the testis and maintained normal Sertoli cell function. As a result, manidipine protected spermatogenesis in SHRSP. These findings also suggested that hypertensive vascular changes in the testes play the most important role in spermatogenic damage in SHRSP.

Animals↗