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Biomedical subjects

T Oishi

Publications and source records attributed to T Oishi.

At least 19 recordsLinked to original sources
PubMed1995

Circadian rhythms of corneal mitotic rate, retinal melatonin and immunoreactive visual pigments, and the effects of melatonin on the rhythms in the Japanese quail.

We investigated circadian ocular rhythms in the Japanese quail, Coturnix coturnix japonica. The birds were placed under light-dark cycles (LD 12:12), constant light (LL) and constant darkness (DD), and the retinas were dissected out at four-hour intervals throughout 24 h. Following measurements were performed. (1) Melatonin content in the retina was measured by radioimmunoassay. It was low in light and several folds higher in darkness under LD 12:12. The rhythm continued in DD, but disappeared in LL. (2) Mitotic figures in the corneal epithelium were counted. Similar rhythms to the melatonin content were observed in the corneal mitotic rate with a slight phase delay. (3) The retinas were fixed at 4-h intervals and immunostained with anti-bovine rhodopsin serum and anti-chicken iodopsin monoclonal antibodies. The outer segments of photoreceptor cells were stained intensively throughout 24 h in LD 12:12, LL and DD. In contrast, the stainability of the locus close to the outer limiting membrane where the Golgi apparatus exists changed diurnally. Scores showing the ratio of cells with positive staining indicated high values from 4 h after the onset of light to the beginning of dark phase under LD 12:12. The values were high throughout 24 h in LL and intermediate or low in DD. (4) To investigate the effect of melatonin on the corneal mitotic rate and visual pigments at the Golgi region, melatonin was injected into one eye and saline into the contralateral eye. Melatonin induced a phase advance in the corneal mitotic rate under LD 12:12, but did not induce a rhythm under LL.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effects of restricted feeding on the light-induced body weight change and locomotor activity in the Djungarian hamster.

To investigate the role of food intake in seasonal body weight changes in the Djungarian hamster, we divided animals, which had minimum body weights after 18 wk in SD, into ad-lib feeding and restricted feeding groups under a long day (LD) and a short day (SD) photoperiods. In the ad-lib feeding groups, body weight and food intake increased in parallel after 3 wk under LD and after 6-7 wk in SD because of photorefractoriness. In the restricted feeding groups, almost all animals moved around furiously (food-seeking activity) when they came to consume all the food provided at 2-3 wk of the treatment in LD and after several weeks in SD with the initiation of photorefractoriness, and ended up with death. In the restricted feeding groups, body weight increase was not observed. The furious food-seeking activity in the restricted groups and the increase of body weight specific food intake (food intake/body weight) in the ad-lib feeding groups might reflect the increased requirement for food. This increase of requirement for food seems to be one of the critical factors regulating the seasonal body weight change.

Animals↗
PubMed1995

Local injection of bicuculline into area 8 and area 6 of the rhesus monkey induces deficits in performance of a visual discrimination GO/NO-GO task.

While performing a symmetrically reinforced visual discrimination GO/NO-GO task, five monkeys were injected with a GABAA antagonist, bicuculline methiodide (BMI), into Brodmann's area 9, 8, 6, or 4. The task consisted of five periods: START, OFF, CUE, RESPONSE, and an inter-trial interval. The monkey was trained to make either the GO response (lever release) or the NO-GO response (continued pressing of the lever), depending on the color of the cue, during the RESPONSE period. Analysis was limited to 102 sites in which muscle convulsions of the forelimb and/or shoulder did not result from BMI injections. Errors in performance increased 10-60 min after injection into 10 of 33 sites in area 9, 9 of 25 sites in area 8, 20 of 34 sites in area 6, and 2 of 10 sites in area 4. The number of trials finished in a 120-min session decrease. Injections induced PRE-RESPONSE errors (release of the lever in either the OFF or CUE periods), GO RESPONSE errors (failure to release the lever when signaled), and NO-GO RESPONSE errors (release of the lever despite a signal not to release). The results suggest that both areas 8 and 6 are involved in correct performance of the GO/NO-GO task.

Animals↗
PubMed1995

An in vitro culture method for chick embryos obtained from the anterior portion of the magnum of oviduct.

1. Chick embryos, obtained from the anterior portion of the magnum of the oviduct 60 to 80 min after the preceding egg had been laid, were cultured in vitro in small and large recipient eggshells until hatching. 2. Of 82 embryos cultured, 46.3% had survived to day 4 of incubation, and 19.5% survived to hatching. 3. The method for culturing embryos used in this experiment could facilitate research on the in vitro manipulation of early chick embryos.

Animals↗
PubMed1995

Effect of vasopressin V1- and V2-receptor stimulation on blood pressure in DOCA-salt hypertensive rats.

We recently reported that stimulation of the arginine vasopressin (AVP) V1-receptor enhanced the pressor response in spontaneously hypertensive rats (SHR). In the present study, we investigated acute changes in systolic blood pressure (SBP) and heart rate (HR) after intravenous injections of AVP, OPC-21268 (a V1-receptor antagonist), and OPC-31260 (a V2-receptor antagonist), in anesthetized DOCA-salt hypertensive rats (DOCA) and age-matched sham-operated Wistar rats (control) to determine whether the pressor effect is specific to SHR or is present in other hypertensive animal models. SBP increased significantly in DOCA rats 9 min after injection of AVP 5 ng/kg without a concomitant increase in HR. Neither OPC-21268 3mg/kg nor OPC-31260 3mg/kg caused significant changes in SBP or HR. SBP tended to increase when AVP was administered after injection of OPC-31260. HR increased significantly 15 min after the combined treatment with OPC-31260 and AVP in DOCA rats compared with control rats. SBP did not change significantly when AVP was administered after injection of OPC-21268 in DOCA or control rats, but HR decreased significantly from 1 to 4 min after injection of AVP in DOCA rats. Our results suggest that V1-receptor stimulation does not enhance the pressor response in the DOCA rat, which is a model of volume-dependent hypertension, suggesting that the AVP system, especially V1-receptor, is not as important in the development or maintenance of hypertension in DOCA rats as in SHR.

Animals↗
PubMed1995

Enhanced pressor response in spontaneously hypertensive rats induced by stimulation of vasopressin-V1 receptors.

To elucidate the effect of the arginine vasopressin (AVP) system in vivo, especially V1 and V2 activity, on blood pressure, we measured the acute changes in blood pressure and heart rate after AVP, OPC-21,268 (a V1 receptor antagonist), and OPC-31,260 (a V2 receptor antagonist) were injected intravenously in anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at the age of 15 weeks. Compared with the control period, single injection of AVP 5 ng/kg significantly increased systolic blood pressure in WKY rats without a concomitant increase in heart rate, but there was no significant increase in blood pressure in SHR. In contrast, single injection of either OPC-21,268 3 mg/kg or OPC-31,260 3 mg/kg did not affect blood pressure or heart rate in either SHR or WKY rats. Injection of AVP after the administration of OPC-31,260 induced a greater increase in blood pressure in SHR than in WKY rats, whereas injection of AVP after the administration of OPC-21,268 did not induce any clear increase in blood pressure in SHR or WKY rats. These results suggest that SHR have enhanced pressor activity mediated by V1 receptors and that this increase may be due to an increase in their number. In conclusion, enhancement of V1 activity may contribute to the development of high blood pressure in SHR.

Animals↗
PubMed1995

Crohn's disease associated with growth hormone secretory dysfunction.

A 10-year-old boy presented in 1989 with repeated episodes of vomiting, abdominal distension and severe growth retardation. Endocrinologic examination indicated growth hormone (GH) secretory dysfunction. Administration of recombinant human GH (rhGH) led to growth, but the patient discontinued treatment. He was readmitted to our hospital in 1993, at the age of 16. His stature was very short. Laboratory findings suggested malnutrition. Radiologic examination revealed regional stenosis and a cobblestone appearance of the intestine. The histologic diagnosis was compatible with Crohn's disease. Administration of prednisolone alleviated gastrointestinal symptoms with the improvement of GH secretory function.

Child↗
PubMed1995

Multienzyme control serum (Seraclear-HE) containing human enzymes from established cell lines and other sources. 2: Evaluation as candidate working enzyme Reference Material for alanine and aspartate aminotransferases.

Seraclear-HE, containing seven enzyme analytes from human sources, was evaluated as an intermethod calibrator for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to transfer Reference Method values to seven routine methods, including one based on hydrogen peroxide detection for possible unification of values (interlaboratory comparability of data). The commutabilities of AST from erythrocytes and ALT from a hepatoma cell line were studied between the consensus methods of Japan Society of Clinical Chemistry (chosen as the Reference Methods) and each of the automated routine methods at reaction temperatures of 30 degrees C and 37 degrees C. For AST, calibration of patients' sera with Seraclear-HE decreased average intermethod variation (CV) from 12% to 2%; for ALT, the decrease was from 20% to 3%. For both enzymes, Seraclear-HE was judged to be commutable between the Reference Methods and each of the methods investigated. The limitations for such use are discussed.

Alanine Transaminase↗
PubMed1995

[Idiopathic acquired generalized anhidrosis with normal numbers of eccrine gland nerve terminals and unmyelinated axons. A case report].

A 37-year-old man with acquired generalized anhidrosis but without other autonomic or somatic abnormalities (idiopathic acquired generalized anhidrosis) is described with special reference to histologic and morphometric findings of the eccrine gland and its nerve terminals and unmyelinated axons. The patient was admitted to our hospital in August 1989 with complaints of heat intolerance and anhidrosis of the face, trunk, and both limbs. General physical and neurological examinations revealed no abnormalities except generalized anhidrosis. Sweating tests revealed anhidrosis of most surfaces of the body except the axillae, mammary areolae, forearms, hands, popliteal fossae, and plantar surfaces. Sympathetic skin responses were absent in the axillae, and were decreased on the palms. Iontophoretically applied pilocarpine revealed a complete absence of active eccrine glands on the dorsal surface of the right foot. No other abnormalities were revealed by autonomic function tests. Light and electron microscopic studies of the eccrine glands of the distal and lateral aspects of the left leg were performed in this patient and six control subjects. Infiltration of mononuclear inflammatory cells around the duct and secretory coil of a limited number of eccrine glands on multiple sections was found only in this patient. Electron microscopic morphometric evaluation of the eccrine glands, associated nerve terminals and unmyelinated axons of this patient revealed no definite alterations when compared with those of the six control subjects. Therefore, we concluded that the nerves innervating the eccrine glands were not affected in this patient and suspect that either the cholinergic receptors or the function of secretory cells of the eccrine glands were involved.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Liposome-mediated DNA transfer into chicken primordial germ cells in vivo.

In embryogenesis, avian primordial germ cells (PGCs) circulate temporarily in the blood vessels at stages 10-15 (Hamburger and Hamilton, 1951), before reaching the gonads. In an attempt to transfer cloned genes into PGCs, liposome consisting of reporter plasmid DNA and N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammoniummethylsulf ate was injected into the marginal veins of embryos at stages 11-15. As reporter plasmids, pRSVZ and pAcZ harboring the Escherichia coli lacZ gene driven, respectively, by the Rous sarcoma virus (RSV) promoter and the chicken beta-actin gene promoter were used. First, 55 embryos were injected with liposome containing pRSVZ and stained for the bacterial beta-galactosidase activity 24 hr after injection. In all the embryos, cells positive for beta-galactosidase activity were observed among the blood cells, endothelial cells, and endocardium cells of the heart, suggesting that transfection took place within the circulatory system. Then, embryos were injected with liposome containing pRSVZ or pAcZ, and stained 2 or 3 d after injection. PGCs positive for beta-galactosidase activity were observed in the gonads in four out of 44 embryos injected with pRSVZ, and 29 out of 71 embryos injected with pAcZ, indicating that the plasmid DNA was transferred into PGCs developing normally. The average number of positive PGCs per embryo was 0.2 and 2.1, respectively, when pRSVZ and pAcZ were introduced. The difference in the number of positive PGCs detected after introduction of the two plasmids suggests that the actin promoter has a higher level of transcriptional activity in PGCs than does the RSV promoter.

Animals↗
PubMed1994

Visual pigments in the pineal complex of the Japanese quail, Japanese grass lizard and bullfrog: immunocytochemistry and HPLC analysis.

We investigated localization of visual pigments in the pineal complex of Japanese quail, Japanese grass lizards and bullfrogs immunocytochemically by use of the antiserum against bovine rhodopsin (Rh-As) and monoclonal antibodies against chicken iodopsin (Io-mAb). We also analyzed retinoids, chromophores of visual pigments, by a high performance liquid chromatography (HPLC). The outer segments and cell membranes of some photoreceptor cells in the pineal organ of the Japanese quail exhibited immunoreactivity to Rh-As, but there are also many immunonegative cells. The number of immunoreactive cells among individuals varied. Immunoreactivity to Io-mAb was weak or did not exist. The HPLC analysis revealed peaks of 11-cis and all-trans isomers of retinal in the oxime extracts of the pineal organ of Japanese quail and chickens. In the pineal of Japanese grass lizards, the outer segments of some cells were immunopositive to Io-mAb, but there were no cells immunoreactive to Rh-As. The parietal eye exhibited a well-developed lens and photoreceptor cells, but the outer segments of photoreceptor cells were immunonegative to both Rh-As and Io-mAb. In bullfrogs, three types of cells were identified in both the pineal and frontal organ; (1) immunopositive to Rh-As, (2) immunopositive to Io-mAb and (3) immunonegative to either of the antibodies. In the pineal organ of bullfrogs, 11-cis and all-trans retinal and 11-cis 3-dehydroretinal were detected, and 11-cis and all-trans retinal were also detected in the frontal organ. We detected 11-cis and all-trans retinal in the ventral part of diencephalon including the hypothalamus. Thus, the chromophore is the same between the retinal and pineal visual pigments, but the expression of opsins is different between the retina and pineal complex, which probably reflects the different function of each organ.

Animals↗
PubMed1994

Immunoreactivities to rhodopsin and rod/cone transducin antisera in the retina, pineal complex and deep brain of the bullfrog, Rana catesbeiana.

Birds and lower vertebrates are known to have extra-retinal photoreceptors in the pineal complex and deep brain. Although the photoreceptive function of the pineal complex has been investigated well, the exact location and nature of the deep brain photoreceptors are not known. In this study we tried to localize visual pigments and signal transduction proteins immunohistochemically in the brain of bullfrogs (Rana catesbeiana). The retina, and the brain with the pineal and the frontal organ were fixed with Zamboni's fixative and/or Bouin's solution. Immunoreactivities to three antisera against bovine rhodopsin (Rh-As), alpha-subunits of bovine rod (anti-pTr alpha) and cone transducin (anti-pTc alpha) were shown in the retina, pineal, frontal organ and hypothalamus. The retina and pineal were immunopositive to both Rh-As and anti-pTr alpha, whereas the frontal organ was immunopositive to only Rh-As and the hypothalamus was immunopositive to all three antisera. The cells which were immunoreactive to Rh-As, anti-pTr alpha and anti-pTc alpha were observed in the preoptic nucleus and suprachiasmatic nucleus in the hypothalamus. The shape of these immunoreactive cells in the hypothalamus was round or spindle-like with one or two immunoreactive nerve processes most of which were perpendicular to the ventricular surface. Western blot analysis of the hypothalamus, pineal and frontal organ demonstrated immunoreactive bands molecular weight of which corresponded to those of the retina (34 kDa, 38 kDa and 41 kDa). Thus, visual pigments and transducin-like proteins seem to exist in the hypothalamus as well as the pineal complex of frogs.

Animals↗
PubMed1994

In vitro micro-autoradiography of atrial natriuretic peptide in biopsy specimens from patients with renal diseases.

We investigated the localization and density of atrial natriuretic peptide (ANP) receptors in human renal biopsy specimens by using in vitro micro-autoradiography (ARG) of [125I]-alpha-human (1-28) ANP. In a preliminary study, we measured the effect of storing tissue samples on ANP binding, using in vitro micro-ARG of Wistar rat kidney under optimal conditions. Duration of the preservation period did not affect ANP binding to renal tissue until samples had been stored at -30 degrees C for two years. A total of 11 human renal tissues were used to assay binding of ANP-ARG, including normal tissue obtained after nephrectomy because of renal cancer. ANP binding occurred predominantly within the glomerulus and, to a lesser extent, in the tubular region both in rat kidney sections and in human renal biopsy specimens. The density of ANP binding, calculated by counting grains in fixed areas, was compared with normal and pathological tissues. The density of grains tended to decrease in patients with renal dysfunction and hypertension except for one case of IgA nephropathy with normal renal function and blood pressure. The density of grains increased in a patient with nephrogenic diabetes insipidus. In the present study, we have established a method that uses in vitro micro-ARG for assessing ANP binding in human biopsy specimens.

Animals↗
PubMed1993

Breeding cycles and fecal gonadal steroids in the brown dipper Cinclus pallasii.

Breeding cycles and fecal gonadal steroids were investigated in free-living brown dippers, Cinclus pallasii. The brown dippers were marked with colored leg bands, and their behavior was observed by a field scope. The breeding season was divided into six stages according to the behavior observed; winter territory-defending, nest-building, copulation, incubation, nestling, and fledgling stages. Fecal pellets on the stones in their territories were collected and the levels of immunoreactive estradiol-17 beta (E2) and testosterone (T) in 10 mg feces were measured by radioimmunoassay. Levels of fecal E2 were high only during the copulation stage, which lasted for a few weeks, in all females of the three pairs observed. In contrast, T levels in the feces of males increased in late winter when intensive territory-defending behavior was observed, and remained high until the end of the breeding season. T levels during the nest-building stage and the copulation stage were similar to those during other nesting stages. When the birds breed only once a year, the duration of high levels of T was shorter than that of the pair with the second clutch. T levels in the feces of females showed a similar pattern to E2 levels.

Animals↗
PubMed1993

Sulfhydryl drugs reduce neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the mouse.

Striatal levels of dopamine and its metabolites 3-methoxy-4-hydroxy-phenylacetic acid (DOPAC) and homovanillic acid (HVA) decreased 7 days after subcutaneous injection of MPTP (20 mg/kg) to the mouse. Striatal GSH contents decreased and GSSG/GSH ratios increased one hour after subcutaneous administration of MPTP. Pretreatments of both cysteamine (200 mg/kg, s.c.) and dimercaprol (20 mg/kg, i.m.) reduced the MPTP-induced decreases in striatal dopamine, DOPAC and HVA, and also prevented the MPTP-induced decreases in GSH levels and increases in GSSG/GSH ratios. On the other hand, injection of cysteamine did not modify the MPTP-induced decreases in striatal levels of dopamine and its metabolites when it was done 2 hours after MPTP administration. Moreover, pretreatment of cysteamine did not affect striatal concentrations of MPP+ in MPTP-treated mice. These results suggest that sulfhydryl drugs such as cysteamine and dimercaprol may reduce neurotoxicity of MPTP probably via changes in redox cycle of glutathione in the brain.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1993

Neurological manifestations of hemorrhagic colitis in the outbreak of Escherichia coli O157:H7 infection in Japan.

An outbreak of hemorrhagic colitis associated with Escherichia coli O157:H7 occurred in a kindergarten in Saitama, Japan from September to November, 1990. Seven patients admitted to our hospital showed neurological manifestations: generalized seizures, impaired consciousness, urinary incontinence, gaze nystagmus, phrenic nerve palsy, action tremor and vertigo. Two patients died. On the basis of the clinical courses and laboratory findings of the seven patients and postmortem findings of one case, these neurological symptoms were suspected to be induced by the verotoxin elaborated by Escherichia coli O157:H7.

Bacterial Toxins↗
PubMed1993

[Alveolar epithelial permeability in bronchial asthma in children. An evaluation by 99mTc-DTPA inhalation scintigraphy].

To evaluate alveolar epithelial permeability (kep) in children with bronchial asthma, 99mTc-DTPA (diethylene triamine penta acetate) aerosol lung inhalation scintigraphies were performed. There was no correlation between the kep value and the severity of asthma. On the other hand, out of 10 the cases which had no aerosol deposition defect in the lung field, 4 showed high kep values on the whole lung field and 7 had high kep value areas, particularly apparent in the upper lung field. These results suggest that even when the central airway lesions are mild, severe damage exists in the alveolar region of the peripheral airway.

Administration, Inhalation↗