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Biomedical subjects

K Kurihara

Publications and source records attributed to K Kurihara.

At least 73 records · Page 4Linked to original sources
PubMed1998

Effects of cGMP and sodium nitroprusside on odor responses in turtle olfactory sensory neurons.

The effects of cGMP and sodium nitroprusside (SNP) on odor responses in isolated turtle olfactory neurons were examined. The inward current induced by dialysis of a mixture of 1 mM cAMP and 1 mM cGMP was similar to that induced by dialysis of 1 mM cAMP or 1 mM cGMP alone. After the neurons were desensitized by the application of 1 mM cGMP, 3 mM 8-(4-chlorophenylthio)-cAMP, a membrane-permeable cAMP analog, did not elicit any current, indicating that both cAMP and cGMP activated the same channel. Extracellular application of SNP, a nitric oxide (NO) donor, evoked inward currents in a dose-dependent manner. However, application of SNP did not induce any currents after desensitization of the cGMP-induced currents, suggesting that SNP-induced currents are mediated via the cGMP-dependent pathway. Application of the cAMP-producing odorants to the neurons induced a large inward current even after neurons were desensitized to a high concentration of cGMP or SNP. These results suggest that the transduction pathway independent of cAMP, cGMP, and NO also contributes to the generation of odor responses in addition to the cAMP-dependent pathway.

Animals↗
PubMed1998

Distribution of neuropeptide-containing nerve fibers in the salamander taste organs.

Salamander taste organs were recognized as oval cell clusters within the dorsal surface of the tongue. A moderate number of SP, CGRP, VIP, NPY, and GAL immunoreactive nerve fibers terminated in the cell clusters, and some of them penetrated into the basal half of the cell clusters. Around the glands, VIP, NPY, and GAL fibers were numerous, and SP and CGRP fibers were less numerous. Immunoreactivity of SOM and FMRF was not detected either in the nerve fibers associated with the cell clusters or those around the glands. These findings suggest that the chemosensory mechanisms of the salamander gustatory organs are under the control of peptidergic innervation. In addition, the present study indicates that the caudate taste organs are structurally primitive but functionally mature.

Animals↗
PubMed1998

Distribution of VIP receptors in the human submandibular gland: an immunohistochemical study.

Distribution of vasoactive intestinal polypeptide (VIP)-immunoreactive nerve fibers and VIP-receptor (VIP-R)-immunoreactive sites in the human submandibular gland were examined by the peroxidase-antiperoxidase method using the specimens taken from patients that had not received radiotherapy. VIP-immunoreactive fibers were found around both serous and mucous acini, the duct system, and those around the mucous acini were more numerous than those around the serous acini. VIP-R immunoreactivity was restricted to the mucous acini and the intercalated duct segment. The serous acini, striated duct, and excretory ducts lacked VIP-R immunoreactivity. These findings suggest that the mucous acinar cells contain VIP-R, and that VIP-R-mediated VIP action is involved in regulating synthesis of viscous saliva and its release.

Aged↗
PubMed1998

High-temperature, nonradioactive primer extension assay for determination of a transcription-initiation site.

We have developed a simple and safe method for the determination of a transcription-initiation site. In this method, reverse transcriptase of the avian myeloblastosis virus or rTth DNA polymerase from Thermus thermopilus was used with a fluorescein isothiocyanate (FITC)-labeled primer. The primer-extension reaction can be performed at a high temperature, which reduces the hindering effect of the secondary structure in RNA, and can omit the annealing step between RNA and the primer. Almost all steps can be done in one tube. This procedure can provide reliable and reproducible data when compared with the conventional procedure at low temperature. Moreover, the sequencing ladder that is required for determining the position of extended products can be obtained with the same FITC-labeled primer.

DNA↗
PubMed1998

[Polymyalgia rheumatica and myelitis associated with anti-cardiolipin antibody].

A 78-year-old woman was admitted to our hospital on September 14, 1992, because of systemic myalgia and stiffness, joint pain, and gait disturbance. She had begun to feel headache and pain in the neck and shoulder in the middle of August, 1992. The pain became systemic, and was accompanied by a low-grade fever, which was unresponsive to NSAIDs. On admission, she had no joint swelling or deformities in the extremities. Neurological examination revealed weakness in the right leg, hypoalgesia below the left C4 level, hyperreflexia in the right extremities, and right Babinski's sign. The erythrocyte sedimentation rate was very high (100 mm/h). Levels of other acute phase reactants were also high. Tests for antinuclear antibody and anti-cardiolipin antibody were positive, but a test for rheumatoid factor was negative. Creatine kinase activity was within normal limits. A T1-weighted magnetic resonance image of the cervical spine at 0.5 T showed an intramedullary low signal. A T2-weighted image showed a borderless spindle-like high signal. Four nodules enhanced by Gd DTPA were seen at C1-C4. The age at onset, myalgia, stiffness, and erythrocyte sedimentation rate were considered to be consistent with a diagnosis of polymyalgia rheumatica. Glucocorticoid treatment was therefore started, and a dramatic clinical improvement was evident within a few days. The patient was discharged from hospital on November 30, 1992. To our knowledge, myelopathy complicated by polymyalgia rheumatica has never been reported previously. Recently, some patients with polymyalgia rheumatica have been reported to have anti-cardiolipin antibody in serum. In the present case anti-cardiolipin antibody may have played a role in the formation of microemboli or in angitis of the cervical spine.

Aged↗
PubMed1998

[Isoproterenol continuous nebulization for childhood status asthmaticus. I. Efficacy and side effects of high-dose method].

We investigated the efficacy and the side effects of "high-dose isoproterenol continuous nebulization" for childhood status asthmaticus. Subjects were 34 children who were hospitalized and underwent the nebulization therapy. The 50 ml solution of 0.5% dl-isoproterenol was diluted in 500 ml of normal saline and nebulized through an ultrasound nebulizer. The period of continuous nebulization was 25.5 +/- 16.0 hours. The Wood's clinical score clearly decreased in 32 cases, the average score changing from 7.7 +/- 0.8 to 2.9 +/- 1.3. Heart rate was elevated significantly during the first 3 hours (156 +/- 25/min at the start of the nebulization, 180 +/- 20/min at 1 hour, 171 +/- 23 at 3 hours), and then it decreased gradually to 122 +/- 25/min at the cessation of the nebulization. Serum GOT, LDH, CPK, and potassium were elevated after the nebulization compared with the values before the treatment, though the changes were not statistically significant. CPK-MB fraction after the nebulization was higher than normal range in 12 of 13 subjects. Of 34 subjects, 11 (32%) complained nausea or vomited, 2 showed arrhythmia on ECG (ventricular premature conduction), 1 developed myocardiac infarction, and 1 developed possible heart failure, some of which might be attributable to the pharmacological side effects of isoproterenol nebulization. We conclude that "high-dose isoproterenol continuous nebulization" is an effective method for childhood status asthmaticus, but there is some risk of serious side effects. This method was originally developed as a method indicated for the case of respiratory failure or threatened respiratory failure following status asthmaticus, and we should not extend the indication of this method thoughness.

Administration, Inhalation↗
PubMed1998

[Isoproterenol continuous nebulization of childhood status asthmaticus. II. Efficacy and side effects of low-dose method comparing with high-dose method].

We investigated the efficacy and side effects of "low-dose isoproterenol continuous nebulization" for childhood status asthmaticus, and compared them with those of "high-dose method". "Low-dose" is defined as 10 ml or less of 0.5% dl-isoproterenol solution diluted in 500 ml of normal saline. Subjects were 23 children who were hospitalized and underwent the nebulization therapy. The period of continuous nebulization was 26.3 +/- 12.5 hours. The Wood's clinical score clearly decreased in 22 cases, the average score changing from 7.3 +/- 1.2 to 2.8 +/- 1.5. Heart rate was not elevated significantly during the nebulization period, and decreased gradually (142 +/- 22/min at the start of the nebulization, 145 +/- 22/min at 1 hour, and 134 +/- 23/min at 3 hours, and 103 +/- 13/min at the cessation of the nebulization). Serum GOT, LDH, CPK, and potassium were decreased after the nebulization compared with the values before the treatment, the changes of the last 2 items being statistically significant. Two subjects who had vomited before the nebulization therapy complained nausea during the procedure, and one experienced transient finger tremor. We conclude that "low-dose isoproterenol continuous nebulization" is an effective and safe method for childhood status asthmaticus. We expect that this method will be familiar to all clinicians.

Bronchodilator Agents↗
PubMed1998

Flight coverall microclimate evaluation using a Japanese type sweating mannequin.

BACKGROUND: It is important to examine the microclimate of a pilot's clothing to evaluate the heat stress the clothing imparts on a pilot, but problems arise with regard to individual variation (phenotype of the pilot, sweating dose, wear condition of the flight coveralls, etc.). HYPOTHESIS: The present study used a Japanese type sweating mannequin (TOM-III) to evaluate the microclimate of flight coveralls. METHODS: TOM-III (TOYOBO, Co., Ltd., Tokyo, Japan) has a characteristic Japanese human body type, and the sweat rate and body temperature can be regulated (240 g of sweat per hour, 36.0 degrees C). The microclimate of the clothing was evaluated by means of 20 temperature/humidity sensors located on the surface of the mannequin skin. TOM-III wore four different assemblies of clothing (CWU-66/P USAF chemical defense flight coverall; JASDF summer-type flight coverall which is similar to the nonchemical defense USAF flight coverall; ordinary 100% cotton underwear; and CWU-66/ P with cotton underwear). We put TOM-III in climatic chamber (21.2 +/- 0.5 degrees C, 50.0 +/- 3.0% relative humidity (RH), 0.1 m air flow x s(-1), dressed in test clothing, and measured the inside temperature (IT) and inside relative humidity (IRH) of the clothing for 60 min (10 min non-sweating, 30 min sweating and 20 min non-sweating). RESULTS: Approximately 5 min after the onset of sweating, the IRH of the CWU-66/P (38.0%) was lower than JASDF flight coverall (42.1%; p < 0.01). At the end of the sweating period, the IRH of the CWU-66/P and the JASDF flight coverall were 46.2% and 52.6%, respectively (p < 0.01). The results indicated that the CWU-66/P flight coverall was better suited for heat stress than the JASDF summer-type flight coverall. CONCLUSIONS: TOM-III may be useful for microclimate evaluation and/or the development of clothing without considering individual variation against various climatic conditions.

Aerospace Medicine↗
PubMed1997

Induction of LIF-mRNA by TGF-beta 1 in Schwann cells.

Schwann cell is a cell type that forms myelin sheath and provides trophic supports for neuronal cells by producing neurotrophic factors such as neurotrophins and neurokines in both normal and traumatic situations. It was recently reported that after lesion of sciatic nerve, mRNA for cholinergic differentiation factor (CDF)/leukemia inhibitory factor (LIF) is induced in nonneuronal cells in the nerve. However, the source of LIF-mRNA and the mechanism of LIF-mRNA regulation have remained largely unknown. In the present study, we searched for factors regulating the LIF-mRNA expression in cultured Schwann cells isolated from newborn rat sciatic nerve. Among various growth factors and cytokines tested, TGF beta-1 exerted the most prominent effect on the induction of LIF-mRNA in the cultured Schwann cells. The effect of TGF-beta 1 on the increase of LIF-mRNA levels was suppressed by either staurosporine or H-7 suggesting the role of PKC or PKC-like protein kinase activity in the induction of LIF-mRNA. The induction of LIF mRNA by TGF-beta 1 was suppressed in the co-culture of the Schwann cells with embryonic rat DRG neurons. The addition of ascorbic acid, which is known to promote myelination in this co-culture system, further suppressed the TGF-beta 1 induction of LIF-mRNA. These results suggest that Schwann cells respond to TGF-beta 1 in a lesion situation to produce LIF, which supports neuronal survival and regeneration. The re-establishment of neuron-Schwann cell interaction would in turn suppress the LIF production to terminate its action during the lesion situation.

Age Factors↗
PubMed1997

Differential and coordinated regulation of expression of norepinephrine transporter in catecholaminergic cells in culture.

The norepinephrine transporter (NET) terminates noradrenergic neurotransmission at synapse by high-affinity sodium-dependent reuptake into presynaptic terminals, and thus serves as a marker of differentiation of noradrenergic neurons. In the present study, we studied the regulatory mechanism of the expression of NET-mRNA in cultured neurons from newborn rat superior cervical ganglia (SCG) and in clonal rat pheochromocytoma cells (PC12) SCG neurons in culture expressed a high level of NET-mRNA, which was further increased 2.5-5 fold from day 1 to day 13. Treatment of SCG neurons with the cholinergic differentiation factor (CDF)/leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF), neurokines known to induce the switch from adrenergic to cholinergic phenotype in SCG neurons, led to the suppression of the level of NET-mRNA in a concentration dependent manner, concomitantly with the suppression of mRNA for tyrosine hydroxylase (TH), an adrenergic marker enzyme in cultured SCG neurons. On the other hand, retinoic acid, a compound which is also known to increase the expression of choline acetyltransferase, a cholinergic marker enzyme, and suppress the expression of TH in the cultured SCG neurons and PCI2 cells, rather increased the level of NET-mRNA in these two cell populations. Alterations of the Na(+)-dependent norepinephrine transport activity which paralleled the changes in the NET-mRNA levels were confirmed by the [3H]norepinephrine uptake assay. These results indicate that cell extrinsic factors regulate the expressions of NET and TH genes by a common as well as by distinct mechanisms.

Amino Acid Sequence↗
PubMed1997

Blockage of urinary responses by inhibitors for IP3-mediated pathway in rat vomeronasal sensory neurons.

The mammalian vomeronasal system is involved in the effects of urinary chemicals on gonadal functions and sexual behaviors. For example, exposure to urine affects the timing of oestrous cycles in rats. Rat vomeronasal sensory neurons in slice preparation were studied under on-cell patch clamp conditions. We found that urine excreted from male Wistar rats increased impulse frequency in vomeronasal sensory neurons of female Wistar rats. The urinary responses were blocked by an inositol-1,4,5-trisphosphate (IP3)-channel inhibitor (10 microM ruthenium red) or phospholipase C inhibitors (10 microM U-73122 and 1 mM neomycin), suggesting that pheromone-like substances in the urine induce the response in the rat vomeronasal sensory neurons via the IP3-dependent transduction pathway.

Animals↗
PubMed1997

Carnosine-induced inward currents in rat olfactory bulb neurons in cultured slices.

Olfactory neurons are rich in carnosine, which is regarded as a possible neurotransmitter between olfactory neurons and the olfactory bulb neurons. In the present study, we used the organotypic slice culture technique to culture olfactory bulb neurons and explore carnosine's role in the olfactory system. Inward current responses to carnosine upon increases in membrane conductance were recorded under whole-cell voltage-clamp conditions. The inward currents were desensitized during continuous application of carnosine. At carnosine concentrations above 50 microM, the current responses increased with increases in carnosine concentrations. The present results suggest that carnosine serves as an excitable neuroeffector between olfactory neurons and olfactory bulb neurons.

Animals↗
PubMed1997

Two types of microsomal prostaglandin E synthase: glutathione-dependent and -independent prostaglandin E synthases.

Prostaglandin (PG) E synthase was found to be widely distributed in the microsomal fractions of rat organs. Among them, an extremely high activity was seen in the deferent duct (112 nmol/min x mg) and other genital accessory organs (10-20 nmol/min x mg). In non-genital organs, the kidney had the highest activity (8 nmol/min x mg). Most of the PGE synthase activity in these organs required glutathione (GSH). In contrast, the enzyme activity in the heart, spleen, and uterine microsomes did not require GSH for its catalytic activity. In view of these data and those of other enzymatic parameters (Km values for PGH2 or pH optima), we suggest that two different types of PGE synthases, GSH-dependent and GSH-independent enzymes, are present in microsomal fractions of rat tissues.

Animals↗
PubMed1997

Cancer risk after renal transplantation in Japan.

Excess of cancer in patients receiving renal transplantation is well-known in Western countries, but information in Japan remains limited. Our study examined whether excess risk is found in patients receiving renal transplantation in Japan. Between 1970 and 1995, 1155 males and 589 females underwent renal transplantation in 6 hospitals, and a total of 12,982 person-years of observation was accumulated. Malignancies developed in 2.6% of patients; O/E ratio was 2.78. Median interval from renal transplantation to tumor development was 58 months. The interval in the patients receiving medication with cyclosporine-A (CyA) (median, 42.5 months) was significantly shorter than that with non-CyA (median, 95.5 months). Median age at the diagnosis of malignancy was 40 years, which is much younger than that in the general population. Relative risk was highest in renal cancer, followed by thyroid cancer, malignant lymphoma and uterine cancer. A distribution of malignancies was different from that reported from Western countries. These findings showed the excess risk of malignancies in Japan with renal transplants, especially in male patients, similar to that observed in Western countries, though the types of malignancy were different.

Adolescent↗
PubMed1997

Hyperimmunoglobulinemia D in idiopathic retinal vasculitis.

BACKGROUND: We examined four patients who exhibited both idiopathic retinal vasculitis and elevated serum IgD levels. Uveitis caused by Behçet's disease is also associated with high levels of serum IgD. Therefore, the clinical features of these patients were investigated and the possible relationship between retinal vasculitis and elevated serum IgD was examined after undertaking a study of increased IgD levels in patients diagnosed with uveitis. METHODS: The study population was composed of 110 patients: 49 with Behçet's disease, 15 with sarcoidosis, 10 with Vogt-Koyanagi-Harada disease, and 36 with other forms of uveitis. IgD measurements were performed using modifications of the latex photometric immunoassay. Surface IgD (sIgD) expression in peripheral lymphocytes was determined by immunofluorescence, and the correlation between serum IgD levels and the percentage of sIgD-positive cells was examined. RESULTS: Twelve of the 110 patients had an elevated serum IgD. Eight of the 12 had Behçet's disease, and 4 were diagnosed with idiopathic retinal vasculitis. These 4 patients were HLA-A24+ females whose ages ranged from 8 to 25 years. A linear correlation between the serum IgD levels and the percentage of sIgD-positive cells was found. CONCLUSION: Hyperimmunoglobulinemia D state was found in Behçet's disease and idiopathic retinal vasculitis. These diseases may represent a new clinical entity characterized by signs of retinal vasculitis and hyperimmunoglobulinemia D that results from abnormal B cell activation and immune complex-mediated responses.

Adolescent↗
PubMed1997

Alpha-fetoprotein-producing carcinoma of the colon: report of a case.

We report herein the rare case of a 67-year-old man in whom alpha-feto-protein (AFP)-producing carcinoma originated in the transverse colon, describing the clinical course of the patient and the histological features of the tumor. At the age of 63, the patient had been diagnosed as having sigmoid colon carcinoma, and surgery was carried out. However, 4 years later, his fecal occult blood test was positive, and further investigation revealed a transverse colon carcinoma with liver metastasis. The serum AFP measured preoperatively was 10978 ng/ml. Resection of the transverse colon and a liver biopsy were performed, following which his serum AFP level decreased to 4804 ng/ml. Histology of the ulcerated lesion in the transverse colon showed a poorly differentiated adenocarcinoma with a medullary growth pattern. Using an immunohistochemical staining method, AFP-producing cells were detected in the transverse colon carcinoma and the liver metastasis. Based on our experience of this patient and a review of the literature on the few cases previously reported, we conclude that AFP-producing coloretal carcinoma has a tendency to produce blood-borne metastasis and to be associated with a poor prognosis.

Aged↗
PubMed1997

Gastric neuroendocrine carcinoma associated with chronic atrophic gastritis type A.

We report a case of gastric neuroendocrine (NE) carcinoma associated with chronic atrophic gastritis type A (CAG/A) or reversed atrophic type gastritis. A 9 x 6 cm tumor was resected from the stomach to control pain in a 55-year-old Japanese woman with peritoneal dissemination and metastatic tumors of the liver and ovary. Histologically, the tumor was NE carcinoma which showed an organoid structure, but consisted of NE cells with overt cytological atypia and frequent mitotic activity. Multiple microcarcinoids and NE cell micronests (NECMs) were also observed in the atrophic non-neoplastic mucosa of the gastric body. CEA immunoreactivity and a high Ki-67 labeling index were characteristic features of the neoplastic NE cells of the carcinoma. Although most NE tumors arising from CAG/A are typical carcinoid tumors, the present case illustrates that a high-grade NE carcinoma can develop from diverse NE cell proliferation in association with CAG/A.

Biomarkers, Tumor↗