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Biomedical subjects

H Ogata

Publications and source records attributed to H Ogata.

At least 217 records · Page 12Linked to original sources
PubMed1995

Assessment of autonomic function in traumatic quadriplegic and paraplegic patients by spectral analysis of heart rate variability.

We analyzed by means of autoregressive spectral analysis the spontaneous beat-to-beat heart rate variability (HRV) of quadriplegic and paraplegic male subjects at rest in the supine position. In agreement with our previous study, in nine of 15 quadriplegic patients only the high-frequency (HF: center frequency = respiratory frequency) component (a marker of vagal modulation of heart rate) was observed. In contrast, in six of the quadriplegic patients both the HF component and the low-frequency (LF: center frequency at approx. 0.1 Hz, 0.03-0.15 Hz in this study) component (a marker of sympathetic and vagal modulation of heart rate) were observed. However, in six quadriplegic patients who presented the LF component, (i) the center frequency of the LF component was lower than that in 10 healthy, sedentary, age-matched males (control I) (P < 0.01), (ii) the power of the HF component was smaller than that in the control-I group (P < 0.01) and (iii) the LF/HF power ratio (an index of sympathovagal balance) was larger than that in the control-I group (P < 0.05). On the other hand, in nine paraplegic patients with an intact 1st-4th thoracic spinal cord, from which the cardiac sympathetic nerves originate, the total power, the power of the LF component and that of the HF component were smaller than those in nine healthy, sedentary, age-matched males (control II) (P < 0.05, P < 0.01 and P < 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Long-term repopulation of hematolymphoid cells with only a few hemopoietic stem cells in mice.

A PCR-based assay has been devised for the detection and semiquantitation of cells originating from a few donor hematopoietic stem cells (HSCs) in a background of recipient cells. Upon sequencing a segment of murine Y chromosome contained in the plasmid pY2, oligonucleotide primers were designed for specific amplification of the Y chromosome-restricted segment. The HSCs were isolated from the bone marrow of mice on day 4 following a single i.v. injection of 5-fluorouracil and were readily distinguished from other bone marrow elements by the characteristics of low density, absence of lineage-specific surface markers, lack of expression of transferrin receptor, and a high expression of major histocompatibility complex class I antigen. Injection of as few as four such HSCs was shown to produce donor-derived cells (including lymphoid cells) for at least 8 months after transplantation into syngeneic female recipients. Retransplantation, employing 10(6) bone marrow cells from the initial recipients, also yielded clear evidence of repopulation with detectable levels of male donor cells. On statistical grounds, it is clear that long-term repopulation in vivo may result from even a single HSC having the characteristics defined herein.

Animals↗
PubMed1995

Molecular cloning of the rat intestinal trefoil factor gene. Characterization of an intestinal goblet cell-associated promoter.

Intestinal trefoil factor (ITF) is a small peptide bearing the unique motif of intrachain disulfide bonds characteristic of the trefoil family. Previous work had localized expression of ITF primarily within goblet cells in the small and large bowel, making it a candidate gene for the study of the molecular basis of intestinal and goblet cell-specific gene expression. In order to study the regulation of ITF expression, we have cloned the rat ITF gene and sequenced 1.7 kilobases of the 5'-flanking region. RNase protection analysis demonstrated a single transcriptional start site. Various lengths of the 5'-flanking region were linked to the reporter gene luciferase and transfected into the colon cancer cell lines LS174T and Caco-2, representing, respectively, cells with and without goblet cell-like phenotype. Expression in the goblet cell-like LS174T colon cancer cell line was nearly 10-fold greater than expression in Caco-2 cells which exhibit columnar enterocyte-like phenotype. The pattern of goblet cell-associated selective transcription required only 153 base pairs of the rat ITF 5'-flanking sequence. Transfection of a construct of human growth hormone under the control of the rat ITF promoter in the N2 subclone of HT-29 cells demonstrated expression of the reporter gene only in those cells exhibiting a goblet cell phenotype as assessed by expression of immunoreactive mucin. These initial studies of the 5'-flanking region of the ITF gene demonstrate the presence of cis-regulatory elements capable of directing goblet cell specific expression.

Amino Acid Sequence↗
PubMed1995

[Brain blood volume measured with near infrared spectroscopy increased after stellate ganglion block].

There are many controversies whether the brain blood flow increases or not after stellate ganglion block (SGB). We found in 10 outpatients that the brain blood volume increased after SGB using near infrared spectroscopy (NIRO500, Hamamatsu Photonics, Inc.). HbO2 showed peak level of 3.6 mumol.l-1 at 30 min and 2.2 mumol.l-1 at 40 min. Peak level of Hb was 5.6 mumol.l-1 at 40 min. These values indicated increased brain blood flow after SGB.

Adult↗
PubMed1995

A genetic algorithm based molecular modeling technique for RNA stem-loop structures.

A new modeling technique for arriving at the three dimensional (3-D) structure of an RNA stem-loop has been developed based on a conformational search by a genetic algorithm and the following refinement by energy minimization. The genetic algorithm simultaneously optimizes a population of conformations in the predefined conformational space and generates 3-D models of RNA. The fitness function to be optimized by the algorithm has been defined to reflect the satisfaction of known conformational constraints. In addition to a term for distance constraints, the fitness function contains a term to constrain each local conformation near to a prepared template conformation. The technique has been applied to the two loops of tRNA, the anticodon loop and the T-loop, and has found good models with small root mean square deviations from the crystal structure. Slightly different models have also been found for the anticodon loop. The analysis of a collection of alternative models obtained has revealed statistical features of local variations at each base position.

Algorithms↗
PubMed1995

Quantitative determination of unchanged cisplatin in rat kidney and liver by high-performance liquid chromatography.

A quantitative analytical method for measuring unchanged cisplatin (CDDP) and high- and low-molecular-mass metabolites (fixed and mobile metabolites) in rat kidney and liver was developed. Unchanged CDDP, separated from fixed and mobile metabolites in tissue homogenates by consecutive procedures of fractionation and ultrafiltration, was determined by high-performance liquid chromatography (HPLC) with post-column derivatization. Although unchanged CDDP was found to be partly metabolized to fixed metabolites during the preparation of cytosolic ultrafiltrates, the recovery of unchanged CDDP gave a constant value (about 70%), which was independent of tissue type and CDDP concentration (from 1 to 10 micrograms/ml). The detection limit for unchanged CDDP in the cytosolic ultrafiltrate was 20 ng/ml, corresponding to a concentration detection limit of 65 ng Pt per g of tissue in the kidney and liver. The concentrations of fixed and mobile metabolites were determined as platinum concentrations in the tissue homogenate and in the cytosolic ultrafiltrate using atomic absorption spectrometry after correcting for transformation of unchanged CDDP to fixed metabolites. The distribution of unchanged CDDP, mobile metabolites and fixed metabolites in rat kidney and liver, after bolus injection of CDDP (5 mg/kg), was determined using this method.

Animals↗
PubMed1995

Effects of sodium thiosulfate on the pharmacokinetics of unchanged cisplatin and on the distribution of platinum species in rat kidney: protective mechanism against cisplatin nephrotoxicity.

To investigate the mechanism underlying the protective effect against cisplatin (CDDP) nephrotoxicity of its antidote, sodium thiosulfate (STS), the effects of STS on the pharmacokinetics of unchanged CDDP and on the distribution of unchanged CDDP and high and low molecular mass metabolites (fixed and mobile metabolites) in the kidney 1 min after a bolus injection of CDDP (5 mg/kg) to rats were studied. A decrease in the plasma concentration of unchanged CDDP and an increase in the plasma concentration of mobile metabolites were observed in the rats after the bolus injection of CDDP in combination with STS infusion for 30 min (1200 mg/kg). Although STS accelerated platinum excretion during the first 10 min after CDDP injection, unchanged CDDP was not excreted in the urine in the STS-treated rats. Total kidney platinum 1 min after the bolus injection of CDDP was detected mainly as unchanged CDDP (86% of the total platinum) in the rats given CDDP alone. However, in the STS-treated rats, the total kidney platinum was decreased to 62% of the level in the rats given CDDP alone, and the platinum species detected in the kidney were mainly mobile metabolites. Only 24% of the total kidney platinum was detected as unchanged CDDP in the STS-treated rats. The loss of body weight and increases in BUN and serum creatinine levels usually observed after a bolus injection of CDDP were completely prevented by STS coadministration. The present study provides information about unchanged CDDP pharmacokinetics and the distribution of unchanged CDDP and some of its generic metabolites in the kidney when STS is coadministered as an antidote. These results show that the protective effect of STS against CDDP nephrotoxicity can be attributed to the formation of inactive mobile metabolites by a direct reaction between unchanged CDDP and STS in the systemic circulation, resulting in a reduction in the amount of unchanged CDDP in the kidney.

Analysis of Variance↗
PubMed1995

Peripheral neuropathies in the upper extremities of paraplegic wheelchair marathon racers.

In order to know if peripheral neoropathies in the upper extremities of paraplegic individuals are induced by participating in wheelchair marathon races, we performed nerve conduction studies bilaterally on the median, ulnar, and radial nerves of 10 male wheelchair marathon racers, and on 10 male sedentary paraplegic individuals. In five of 10 paraplegic racers, and in nine of 10 sedentary paraplegics there was a decrease of motor nerve conduction velocities and/or prolongation of motor or sensory nerve distal latencies. Abnormal results in all of the nerve conduction studies were 3.2% and 13.6% in paraplegic racers and sedentary paraplegics, respectively. Although paraplegic racers had fewer peripheral neuropathies in the upper extremities than did sedentary paraplegics, ulnar lesions due to involvement of the deep motor branch and at the elbow were a characteristic feature of nerve injuries, presumably caused by wheelchair marathon racing. It is suggested that although a wheelchair marathon is generally a safe sport, wearing gloves and handling a wheelchair in the correct way during the race are necessary to prevent nerve injuries.

Adult↗
PubMed1995

Sexual activities and concerns in persons with spinal cord injuries.

A survey of sexual activity and concerns of people with spinal cord injury living in the community was undertaken. A questionnaire was sent to 144 people, and 102 replies were collected. Of the sample, 59.8% reported having engaged in some aspect of sexual life. Sexual life ranked the lowest in terms of importance with respect to other aspects of life. However, 47.1% answered that they were not satisfied with their sexual life. It was indicated that the provision of information regarding sexuality should remain a high priority for health care providers.

Adult↗
PubMed1995

Does hypertonic saline have preventive effects against delayed neuronal death in gerbil hippocampus?

This experiment was conducted to ascertain whether or not hypertonic saline solution (HSS) has preventive effects on delayed neuronal death in the hippocampal CA1 subfield of the gerbil. Twenty-eight gerbils were anesthetized with 1% halothane and 50% nitrous oxide during the experimental period. Their common carotid arteries were occluded bilaterally for 2.5 min, immediately after which 2 mL/kg of 10% NaCl was infused via the tail vein. Two mL/kg of physiological saline solution (PSS) was used for the control group in the same manner. 5 days later, after the cerebrum was removed, the hippocampus was stained with hematoxylin-eosin, and histopathological changes in the CA1 subfield were observed under the light microscope. Degenerative or necrotic pyramidal cells were compared among groups. The degeneration rates of the pyramidal cells were as follows; after sham operation with PSS, 4.2 +/- 1.8%; after sham operation with HSS, 6.5 +/- 3.3%; on ischemia-reperfusion with PSS, 95.6 +/- 1.6%; on ischemia-reperfusion with HSS, 7.1 +/- 3.0%. This study suggested that hypertonic saline might prevent delayed neuronal death in the hippocampal CA1 subfield of gerbils subjected to cerebral ischemia-reperfusion.

Animals↗
PubMed1995

Differential effects of vecuronium on the thumb and great toe as measured by accelography and electromyography.

We evaluated possible differential effects of vecuronium on the thumb and great toe using two types of neuromuscular transmission monitor. Train-of-four stimuli were simultaneously applied to the ulnar nerve and tibial nerves using cutaneous electrodes. The responses were quantified with accelographs (thumb and left great toe) and an electromyograph (right great toe). Twenty ASA 1 or 2 patients received, by random allocation, one of two types of anaesthesia: neuroleptanaesthesia or sevoflurane-based anaesthesia. With both techniques, the shortest time to maximum block after vecuronium 0.1 mg.kg-1 occurred in the thumb as measured by accelography. The average (SD) values with neuroleptanaesthesia were: 173(23) s for thumb using accelography; 220(16) s for great toe using accelography; 205(44) s for great toe using electromyography. The average (SD) value(s) with sevoflurane-based anaesthesia were: 137(15) for thumb using accelography; 179(21) for great toe using accelography; 153(23) for great toe using electromyography. The differences between the thumb and great toe were statistically significant during both types of anaesthesia when measured with the accelograph (p < 0.01). The time from completion of maximal block to 25% recovery of twitch height in the thumb was significantly longer than that of the great toe as measured by accelography during both types of anaesthesia (p < 0.05). In contrast, there were no statistically significant differences between time to maximum block and 25% recovery of twitch height of the thumb as measured by accelography compared to the values measured for the great toe using electromyography during either anaesthetic technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Edrophonium as an antagonist of vecuronium-induced neuromuscular block in the elderly.

Train-of-four stimuli were applied to the ulnar nerve using an accelograph in 10 elderly patients (aged 70-82 years) and 10 younger patients (aged 27-54 years). Anaesthesia was induced with thiopentone 5 mg.kg-1 and was maintained with nitrous oxide (66%) oxygen and sevoflurane (1 MAC). Vecuronium 0.1 mg.kg-1 was used for paralysis, and reversed with intravenous edrophonium 0.75 mg.kg-1 and atropine 0.015 mg.kg-1 when the train-of-four ratio returned to 25%. The times from initial administration of vecuronium to completion of maximal block were 211.5 (SD 66.9) s and 154.0 (SD 39.7) s in the elderly and younger patients, respectively (p < 0.05). The times from maximal block to 25% recovery of train-of-four ratio were 64.8 (SD 36.3) min and 61.8 (SD 36.3) min in the elderly and younger patients, respectively. There was no statistically significant difference between them. The reversal times from 25% to 75% of the train-of-four ratio after the administration of edrophonium were 210.0 (SD 136.7) s and 177.0 (SD 100.4) s in the elderly and younger patients, respectively. There was no statistically significant difference between them. The authors were unable to show that healthy elderly patients differ significantly from younger patients in the neuromuscular blocking effect of vecuronium and the reversal effect of edrophonium.

Adult↗
PubMed1995

Tissue expression of Sialyl Tn antigen in gynecologic tumors.

OBJECTIVES: To investigate tissue expression of Sialyl Tn antigen (STN) in gynecologic tumors, and to compare with its appearance in blood circulation. METHODS: Surgical specimens were obtained from 24 patients with malignant gynecologic diseases, including 7 ovarian cancers, 13 cervical cancers, 3 endometrial cancers, and 1 vulval cancer. Control tissues were also obtained at surgery from 28 patients with benign tumors of the ovary or uterus. RESULTS: Anti-STN monoclonal antibody (TKH-2) positively identified 6 (86%) of 7 ovarian cancers, 11 (85%) of 13 cervical squamous-cell carcinomas, but none of 3 endometrial cancers. None of the 28 benign tissues, including 11 ovarian benign tumors, showed positive immunostaining for STN, except 1 with an ovarian chocolate cyst which showed weak staining for STN. No expression was found in normal squamous epithelium distant from the lesion. Serum STN antigen was positive in 4 of 7 ovarian cancers (cutoff = 39 U/ml), but only in 2 of 13 cervical cancers, and none in the 3 endometrial cancers. CONCLUSIONS: These findings indicate different behaviors in the appearance of STN in tumor tissue and blood circulation, and also suggest the possible applicability of STN to immunohistochemical diagnosis of squamous-cell carcinomas.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1995

Return to work after stroke. A follow-up study.

BACKGROUND AND PURPOSE: Few studies have reported the longitudinal trend of return to work after stroke. The purpose of our study was to evaluate the longitudinal trend of proportion of patients who return to work after stroke and further to examine the predictors of return to work while taking follow-up periods into consideration. METHODS: We conducted a retrospective cohort study on the association between characteristics of stroke patients at admission and return to work after first stroke, taking length of follow-up period into consideration (n = 183). The patients were all younger than 65 years and were working at the time of their stroke. A follow-up questionnaire evaluated return to work and related information. Data were analyzed using the Kaplan-Meier method for curves of the proportion of return to work and Cox's proportional hazards model for odds ratios of return to work. RESULTS: The curve of proportion of return to work had two steep slopes, and the proportion was at a maximum at 18 months from patient admission. The adjusted odds ratios of return to work for patients with normal muscle strength versus severe weakness, without apraxia versus with apraxia, and with white-collar versus blue-collar occupations were 5.16 (P < .05), 4.16 (P < .05), and 1.43 (.05 < P < .10), respectively. CONCLUSIONS: The increase of proportion of return to work after stroke was nonlinear, and this trend was referable to the social security systems available to the patients included in this study. Normal muscle strength and absence of apraxia were significant predictors of return to work after stroke. White-collar occupation showed a tendency to promote return to work.

Adolescent↗
PubMed1995

Drug interactions between theophylline and H2-antagonists, roxatidine acetate hydrochloride and cimetidine: pharmacokinetic analysis in rats in vivo.

The effects of roxatidine acetate hydrochloride (Rox) on the pharmacokinetics of theophylline were compared to those of cimetidine in rats in vivo, Cimetidine or Rox was maintained at a steady state level using continuous infusion, then theophylline was injected into the rats as a bolus (7.5 mg/kg). Cimetidine showed competitive inhibition of theophylline elimination in vivo, with an inhibition constant (Ki) of 28.5 microM. Cimetidine significantly decreased the total body clearance and extended the plasma half-life of theophylline, but did not change its volume of distribution. In contrast, Rox did not significantly influence the pharmacokinetics of theophylline in rats. The in vivo animal model used in the present study for investigating the mechanism of the drug interaction showed good agreement with the results obtained in clinical and in vitro studies.

Animals↗
PubMed1995

Dog liver microsomal P450 enzyme-mediated toluene biotransformation.

1. We studied toluene metabolism in dog liver microsomes and the major metabolite was benzyl alcohol with o- and p-cresol as minor metabolites. 2. The enzyme kinetics of toluene biotransformation were examined by means of Lineweaver-Burk analyses. The Michaelis-Menten values differed among the three pathways, the order being; Km, o-cresol > p-cresol > benzyl alcohol; Vmax, benzyl alcohol > o-cresol > p-cresol; and Cl(int), benzyl alcohol > p-cresol > o-cresol. 3. The formation of benzyl alcohol, o- and p-cresol from toluene was substantially inhibited by the P4502E inhibitors such as DDC (diethyldithiocarbamate) and 4-methylpyrazole in all pathways, with IC50's in the range of 0.02-0.59 mM. The P4502B inhibitors, metyrapone and secobarbital also inhibited benzyl alcohol and p-cresol formation, whereas o-cresol was not inhibited by these latter compounds. 4. Anti-rat P4502E1 antibodies inhibited benzyl alcohol, o- and p-cresol formation from 26 to 30% 0.2 ml serum/mg microsomal protein. Furthermore, anti-rat P4502B1/2 antibody inhibited benzyl alcohol and p-cresol formation (47 and 44% respectively), but not that of o-cresol. Anti-rat P4502C11/6 antibody also inhibited benzyl alcohol and p-cresol formation 31 and 24% respectively in a similar manner to that by the anti-rat P4502B1/2 antibody. 5. These results suggested that the P4502B, 2C and 2E isozymes in dog liver contribute to the formation of benzyl alcohol and p-cresol from toluene, and 2E isozyme preferentially contributes to the formation of o-cresol.

Animals↗
PubMed1995

[Influence of stellate ganglion block on respiratory system].

The purpose of this study was to investigate the influence of a stellate ganglion block (SGB) or stellate ganglion electrical stimulation (SGES) on pulmonary resistance, on blood flows of the bronchial, pulmonary and common carotid arteries, and on arterial blood gases. Thirteen mongrel dogs were divided into two groups; a SGB group (n = 8) and a SGES group (n = 5). Anesthesia was induced with pentobarbital 25 mg.kg-1 and the animals were mechanically ventilated to maintain constant PaO2 (90-100 mmHg) and PaCO2 (35-40 mmHg). After a thoracotomy, the SGB with 0.5% mepivacaine 1.5 ml was performed, or the SGES was performed at a strength of 12 volts, and at a frequency of 50 Hz, applied for 30 min. In the SGB group, pulmonary resistance after the block did not significantly differ from the control. No significant change occurred in blood flows of the bronchial and pulmonary arteries, but the common carotid artery flow increased significantly after the SGB. Arterial blood gases did not change significantly after the SGB. In the SGES group, pulmonary resistance after the stimulation did not significantly differ from the pre-value. However, blood flows of the bronchial, pulmonary and common carotid arteries decreased significantly after the SGES. Arterial blood gases did not change significantly after the SGES. These results suggest that the SGB may not influence the respiratory system under normal conditions.

Animals↗