PubMed Health⌕ Search

Biomedical subjects

I Ohkawa

Publications and source records attributed to I Ohkawa.

18 recordsLinked to original sources
PubMed2000

[Use of modified infrared aural canal thermometers during cardiac surgery].

Two kinds of modified infrared aural canal thermometers (Mimippi, Superthermo) are currently available in Japan. We therefore evaluated their accuracy and precision for clinical use. For the purpose of this investigation, we considered accuracy to be the mean difference between the test thermometers and the reference thermocouple. Precision was examined from the standard deviation of the difference between the test and reference values. We evaluated ten patients for cardiopulmonary bypass surgery under mild hypothermia (approximately 32 degrees C). Aural canal temperatures were measured in a random order with each infrared thermometer, and compared with readings from a thermocouple positioned at the contralateral tympanic membrane. Compared with the thermocouple, the Mimippi had regression slope 0.87 and correlation coefficient 0.79. In contrast, slope of the Superthermo regression was 0.74. The correlation coefficient for the Superthermo was 0.71. The accuracy (offset, or bias) was 0.91 degree C with the Mimippi. In contrast, it was 1.32 degrees C with the Superthermo. The precision (standard deviation) of the Mimippi was 0.65. In contrast, it was 0.73 degree C with the Superthermo. We conclude that both thermometers were moderately accurate and precise for perioperative use.

Body Temperature↗
PubMed1999

Apoptosis in favourable neuroblastomas is not dependent on Fas (CD95/APO-1) expression but on activated caspase 3 (CPP32).

The mechanisms of apoptosis in neuroblastomas have been investigated by examining the expression profiles of Fas, Fas ligand (FasL), and caspase 3 in 42 primary tumour tissues. Immunohistochemically, no or weak Fas expression was detected in 25 out of 29 neuroblastomas (86 per cent), whereas high levels of expression of FasL and pro-caspase 3 were noted in 30 and 29 of 42 tumours, respectively (approximately 70 per cent). Overexpression of pro-caspase 3, but not FasL, correlated significantly with a younger age and low tumour stage. Western blot analysis of ten neuroblastomas confirmed the lack of Fas expression and the presence of strong FasL expression in all samples and pro-caspase 3 expression in five tumours, of which four belonged to the favourable type. These favourable tumours also showed vigorous Asp-Glu-Val-Asp (DEVD) hydrolytic, or caspase 3-like activities, while the unfavourable tumour lacked such activity. Moreover, immunostaining for the p17 subunit of the caspase 3 heterodimer showed that active caspase 3 was mainly localized in apoptotic tumour cells. Combined together, our results suggest that caspase 3, activated via a Fas-independent pathway, may play important roles in apoptosis, suppression of growth, and, in some cases, regression of favourable neuroblastomas.

Apoptosis↗
PubMed1998

Efficacy of exogenous fibronectin in wound healing in malnourished rats.

BACKGROUND/PURPOSE: Fibronectin (FN) plays an important role in fibrin matrix formation during the wound healing process. The authors investigated whether exogenous FN increases the bursting strength (BS) of surgical wounds in malnourished rats. METHODS: Ninety rats were grouped according to three nutritional conditions (n = 30 in each group). All animals underwent a transverse celiotomy after 3 weeks of feeding, and FN (2 mg/body/day) was given postoperatively to 15 rats in each of the three groups. Wound BS was measured on postoperative days (PODs) 3, 5, and 7 after removal of the sutures. RESULTS: BS in normally nourished rats (group N; 142.6+/-23.4 mmHg) was significantly higher than that in protein malnourished rats (group PM, 110.2+/-11.2 mm Hg) and protein/ calorie (Cal)-malnourished rats (group PCM, 76.5+/-10.7 mm Hg) on POD 7 (P<.01). However, BS values for groups PM + FN (147.0+/-21.1 mmHg) and PCM + FN (115.1+/-28.9 mm Hg) were intensified significantly in comparison with groups PM and PCM (P<.01). Plasma FN levels in rats of the three FN nontreated groups were similarly decreased on POD 3 or 5, but returned to the preoperative level on POD 7, whereas those for the other three FN-treated groups increased after POD 3. CONCLUSION: Intravenous administration of FN might strengthen the weakened wounds of malnourished animals.

Abdominal Injuries↗
PubMed1994

[Effect of bifemelane hydrochloride in rats on the improvement of the learning and memory impairments and prevention of neuronal damage following transient forebrain ischemia].

Modified four-vessel occlusion in rats caused loss of the passive avoidance response (PAR) and impaired the radial maze performance (RMP). We investigated the effectiveness of bifemelane hydrochloride (bifemelane) in restoring these abilities. After the RMP test, the hippocampal neuronal density following cerebral ischemia was observed histologically and the effect of bifemelane on it examined. Bifemelane was intraperitoneally administered at a dose of 1, 3, 10 mg/kg or 30 mg/kg twice before ischemia and daily following cerebral ischemia. The control rats were given physiological saline in the same manner. At a dose of 10 mg/kg, i.p., bifemelane significantly restored the PAR, which had been lost as a result of 5-min ischemia. At the same dose, it significantly restored the RMP, which had been impaired by 15-min ischemia and prevented neuronal damage in the CA2 region of the anterior hippocampus and the CA1, CA2 and CA3 regions of the posterior hippocampus. The correlation between the memory score and the neuronal density in the CA1 region of the posterior hippocampus was statistically significant. These results suggest that bifemelane might prevent the neuronal damage induced by ischemia and restore impaired learning and memory capabilities following cerebrovascular disease.

Animals↗
PubMed1994

[The usefulness of combined measurements of transcranial Doppler sonogram and somatosensory evoked potentials during hypothermic cardiopulmonary bypass].

Serial and simultaneous measurements of the blood flow velocity of the middle cerebral artery (MCA-V) by transcranial Doppler sonography (TCD) and somatosensory evoked potentials (SEP) were performed in 7 adult patients during hypothermic cardiopulmonary bypass (CPB). CPB was instituted by alpha-stat blood gas management until the rectal temperature stabilized at 24 to 28 degrees C and gas management was converted from alpha to pH-stat by adding 4-7% of CO2 gas into the oxygenator for 10 minutes. MCA-V during hypothermic CPB by alpha-stat management was identical with normothermic prebypass MCA-V. However it significantly increased after pH-stat conversion, suggesting that CO2 reactivity was preserved even in the hypothermic situation above 24 degrees C of body temperature. Latency of all wave components of SEP and central conduction time (CCT) prolonged and wave voltages decreased as the body temperature dropped and SEP waves almost completely recovered following the temperature resumed to the prebypass temperature. There were no significant changes developed in latency and wave forms of SEP by conversion of the blood gas management from alpha-stat to pH-stat. The combined technique of TCD and SEP for detecting the real time changes of cerebral blood flow and brain function is considered to be useful to minimize the brain damage during open heart surgery.

Blood Flow Velocity↗
PubMed1993

Effects of menatetrenone on bone loss induced by ovariectomy in rats.

The effects of menatetrenone, a vitamin K2 homologue, on bone loss induced by ovariectomy in rats were studied in 3 experiments. Menatetrenone was given as a dietary supplement. In experiment 1, at 2 weeks postovariectomy, menatetrenone (10 mg/kg/day given for 2 weeks) inhibited the decrease in bone density of the femoral metaphysis induced by the ovariectomy. In experiment 2, menatetrenone (3 or 30 mg/kg/day given for 6 months) inhibited the decrease in bone strength of the femur and the decrease in calcium and hydroxyproline content of the femoral diaphysis at 6 months postovariectomy. In experiment 3, menatetrenone treatment, at 30 or 100 mg/kg/day for 6 months, protected against the decrease in bone strength and calcium and hydroxyproline content in the bone loss model induced by ovariectomy and calcium-deficient diet. These findings suggest that menatetrenone protects against the bone loss induced by ovariectomy.

Animals↗
PubMed1991

[Effects of mecobalamin on testicular dysfunction induced by X-ray irradiation in mice].

Experimental testicular dysfunction were produced by X-ray irradiation to the testes in mice. Mecobalamin (CH3-B12) was orally administered at a daily dose of 0.01, 0.1 or 1 mg/kg six times a week for 8 weeks from the next day after the irradiation. The control mice received physiological saline in the same manner. On 4th- and 6th-week after the irradiation, the weights of testes and epididymides were decreased, although those of the body and accessory sex glands (seminal vesicle, coagulating gland and prostate) were nearly equal to those of non-irradiated mice. At the same time, the diameter of seminiferous tubules decreased and sperm parameters (sperm count, sperm motility and sperm abnormality) deteriorated. When CH3-B12 (1 mg/kg) was administered, the diameter of seminiferous tubules increased and sperm parameters improved as compared to those of the control. The results indicate that CH3-B12 improved the experimental testicular dysfunction in mice induced by the irradiation. These results suggest that CH3-B12 might accelerate testicular function.

Administration, Oral↗
PubMed1988

[Study on producing rats with experimental testicular dysfunction and effects of mecobalamin].

Experiments were performed to investigate the effects of mecobalamin (CH3-B12) on disorders of testicular function. Male rats received subcutaneously an injection of doxorubicin (ADR) three times a week for 3, 5 and 7 weeks. Thereafter, they were periodically sacrificed for the examination of cauda epididymal sperm profiles and the morphology of the testis. ADR treatment caused a decrease in sperm counts, sperm motility and the diameter of the seminiferous tubules, and an increase in the percentage of abnormal sperms. These damaging effects depended on the dosage and period of treatment with ADR. Based on these findings, rats with testicular dysfunction induced by the treatment with ADR at a daily dose of 0.25 mg/kg, three times a week for 5 weeks were prepared to investigate the effects of CH3-B12 on oligozoospermia. CH3-B12 was given intraperitoneally to the oligozoospermic rats six times a week for 5 and 10 weeks. The results obtained indicated that 1,000 micrograms/kg of CH3-B12 caused a significant increase in both the sperm counts and the diameter of the seminiferous tubules. These results suggest that CH3-B12 is a candidate drug for oligozoospermia.

Animals↗
PubMed1983

[Pharmacological studies of dl-2[3-(2'-chlorophenoxy)phenyl]propionic acid. I. Analgesic and antipyretic effects].

Analgesic and antipyretic effects of dl-2[3-(2'-chlorophenoxy)phenyl] propionic acid (CPP) were studied in mice, rats and guinea-pigs. CPP produced a dose dependent inhibition of acetic acid-induced writhing syndrome. Its ED50 values 1 and 3 hr after oral administration were 47 and 31 mg/kg, respectively. CPP had a potent analgesic effect on bradykinin-induced nociceptive response in rats, and its ED50 value was 15 mg/kg 2 hr after oral administration. The analgesic activity of CPP in these experiments was less potent than that of indomethacin, but it was approximately equivalent to ibuprofen and 10 to 20 times as potent as aspirin. CPP had no analgesic effect on both the tail pinch and hot plate tests in mice, while CPP potentiated the analgesic effect of codeine on these tests. CPP had no effect on the nociceptive response induced by intradermal injection of bradykinin and/or EDTA in guinea-pigs. On the other hand, when CPP was given orally in a dose range of 1.25 to 5 mg/kg, it produced an antipyretic effect on yeast-induced fever in rats. The antipyretic activity of CPP was equivalent to ibuprofen and 10 to 15 times as potent as aspirin.

Analgesics↗
PubMed1981

The orientation of the major coat protein of bacteriophage f1 in the cytoplasmic membrane of Escherichia coli.

The orientation of the major coat (B) protein of the bacteriophage f1, an integral membrane protein in the cytoplasmic membrane of infected Escherichia coli, was examined. Pyridoxal 5'-phosphate and [3H]NaBH4 were used to label the cytoplasmic membrane proteins in spheroplasts and membrane vesicles of E. coli infected with bacteriophage f1. Under the conditions described, tritium incorporation was almost completely dependent on the presence of pyridoxal 5'-phosphate and little if any of the cytoplasmic proteins were labeled when the reaction was applied to intact spheroplasts. The major coat protein was isolated from the cytoplasmic membranes labeled in this manner and the chymotryptic peptides were analyzed for the presence of tritium in the pyridoxamine 5'-phosphate conjugate. When the proteins were labeled in the intact spheroplast, only the NH2-terminal chymotryptic peptide of the coat protein was labeled. If the proteins were labeled during osmotic lysis of the spheroplasts or in isolated vesicles, the chymotryptic peptide containing the COOH terminus of the coat protein as well as the NH2-terminal peptide was labeled. The NH2-terminal peptide was labeled to approximately the same extent as occurred in the intact spheroplast. These results are consistent with the hypothesis that the mature f1 coat protein asymmetrically spans the cytoplasmic membrane of the infected host with its NH2 terminus exposed on the outside and COOH terminus exposed on the cytoplasmic surface.

Amino Acid Sequence↗
PubMed1980

Effect of iron concentration in the growth medium on the sensitivity of Pseudomonas aeruginosa to pyocin S2.

The iron concentration in the growth medium was found to affect the susceptibility of Pseudomonas aeruginosa PML1550 to pyocin S2, a bacteriocin. The efficiency of killing by pyocin S2 was very low when the indicator cells were grown in an iron-rich medium. The capacity of these cells to adsorb pyocin S2 was reduced. Cultivation under limitation of iron (1 microM or less) was necessary to produce a fully sensitive cell population. The growth under iron limitation was accompanied by the appearance of four protein components in the outer membrane of the cells. Nine mutants resistant to pyocin S2 were isolated and their outer membranes were analyzed. They all lacked one component (Fe-b protein) as well as the adsorption capacity for pyocin S2. These findings suggest a possible role of this protein as the receptor for pyocin S2.

Bacteriocins↗
PubMed1979

An esterase on the outer membrane of Pseudomonas aeruginosa for the hydrolysis of long chain acyl esters.

A new esterase activity which hydrolyzes palmitoyl-CoA was found in the membrane fraction of Pseudomonas aeruginosa. All the 11 strains of P. aeruginosa tested possessed this esterase activity. The esterase was constitutive and was fully active on the intact cell bodies toward substrates in the medium. It was located on the outer membrane of the cell envelope, and was not released into the culture medium. This activity was designated as OM (outer membrane) esterase. OM esterase was solubilized from the cell envelope with EDTA-Triton X-100 and purified 690-fold. It was a minor component of the outer membrane. Its molecular weight was approximately 55,000. The activity was rather stable to heat, a wide range of pH, and treatment with detergents and organic solvents. No cofactors were required. The pH optimum of the reaction was 8.5. Among various acyl-CoAs, only long chain (C12--C18) thioesters were hydrolyzed. OM esterase also hydrolyzed some kinds of oxy-esters such as p-nitrophenyl acyl esters, monoacyl esters of sucrose and Tween 80 (polyoxyethylene sorbitan monooleate). On the other hand, triglycerides, phospholipids, or hydrophobic monoesters were not hydrolyzed at all. Thus, this enzyme seems to have specificity for long chain acyl esters with hydrophilic groups, whether thio- or oxy-ester. Mutants deficient in this esterase activity were isolated. These mutants were unable to grow on Tween 80 as a sole carbon source. This suggests a possible role of OM esterase in the utilization of acyl esters as carbon sources.

Acyl Coenzyme A↗
PubMed1976

[Pharmacological studies on degeneration and regeneration of peripheral nerves. (1) Effects of methylcobalamin and cobamide on EMG patterns and loss of muscle weight in rats with crushed sciatic nerve].

Experiments were performed to investigate the effects of Vitamin B12, i.e., methylcobalamin and cobamide, on the neural degeneration and regeneration. Male Wistar rats (140 to 150 g) under conditions of experimental unilateral sciatic nerve crushing were treated consecutively with methylcobalamin (50 and 500 mug/kg/day i.p.), cobamide (50 and 500 mug/kg/day i.p.) or saline. EMG recordings were periodically carried out and rats of each group were sacrificed to determine the weight-loss of denervated muscles 1, 2, 3 and 4 weeks after crush. Neither methylcobalamin nor cobamide exerted any significant effect on body-weight gain of the nerve-crushed rats with a daily injection of 50 and 500 mug/kg i.p.. The EMG pattern of the denervated biceps femoris muscle showed a total lack of fibrillation for 2 days after the nerve-crush. Thereafter, the fibrillation appeared and continued for 10 to 14 days until the nerve had regenerated, as evidenced by the appearance of a complex NMU voltage. The occurrence of fibrillation voltage was slightly delayed in methylcobalamin group (500 mug/kg/day) as compared with the saline control group. The re-appearance of normal NMU voltage was more rapid in the methylcobalamin 500 mug/kg group than in controls and other experimental groups. Neither methylcobalamin nor cobamide had any significant effect on the weight-loss of the gastrocnemius and tibialis anterior muscles following crush of the sciatic nerve. However, a daily injection of 500 mug/kg of methylcobalamin produced a significant increase in the weight of the soleus muscle which recovered to the extent of being the same weight of the contralateral 4 weeks after the nerve-crush. These results suggest that methylcobalamin may have an inhibitory effect on Wallerian degeneration and also a facilitatory effect on the neural regeneration of the crushed sciatic nerve of rats.

Animals↗
PubMed1976

[Pharmacological studies on degeneration and regeneration of the peripheral nerves. (2) Effects of methylcobalamin on mitosis of Schwann cells and incorporation of labeled amino acid into protein fractions of crushed sciatic nerve in rats].

Male Wistar rats (140 to 150 g) in which the unilateral sciatic nerve had been crushed were treated consecutively with methylcobalamin (5, 50 and 500 mug/kg/day i.p.) or saline immediately after the nerve-crush. Thereafter, they were periodically sacrificed for biochemical and histological examinations. At different intervals after the nerve-crush, L-leucine-4,5-T (20 mu Ci/100g, specific activity 15 mCi/m mole) or L-leucine -14C(U) (15 muCi/100g, specific activity 270 mCi/m mole) was given i.p. to some rats of each group and 3 hr later they were sacrificed to determine the rate of leucine incorporation into protein fractions of the crushed nerve and the denervated muscles. The nerve and muscles of the contralateral side served as control. Longitudinal sections of proximal and distal stumps of the sciatic nerve were prepared and stained with hematoxylin and eosin. As compared with saline group, repeated injections of 5, 50 and 500 mug/kg/day of methyl-cobalamin caused a significant increase of the in vivo incorporation of radioactive leucine into the protein fraction of the crushed sciatic nerve 5 to 7 days after the crush. In contrast, a recovery of the increased incorporation of leucine into the crushed nerve was more rapid in methylcobalamin groups than in the saline group. On the other hand, methylcobalamin (5 approximately 500 mug/kg/day i.p.) had no significant effect on the leucine incorporation into the denervated muscles (m. gastrocnemius, m. tibialis anterior and m. soleus). In addition, consecutive injections of methylcobalamin (5 approximately 500 mug/kg/day) did not affect the mitosis of Schwann cells during the period of Wallerian degeneration of the crushed sciatic nerve. These results suggest that methylcobalamin possesses a stimulating effect on proteosynthesis in Schwann cells at the initial stage of axon regeneration and it may facilitate neural regeneration.

Animals↗
PubMedDate not supplied

Effects of menatetrenone on prednisolone-induced bone loss in rats.

This study was carried out to evaluate the effect of menatetrenone, a vitamin K2 with 4 isoprene units, on prednisolone-induced bone loss. Three experiments were performed in rats which received menatetrenone as a dietary supplement. In experiment 1, a soluble form of prednisolone, dissolved in drinking water, was administered to rats at 7 mg/kg/day for 9 weeks. The length, dry weight, and bone density of femurs and tibiae, as well as urinary gamma-carboxyglutamic acid (Gla) content, were significantly lower in the prednisolone-control group than in the intact group. Menatetrenone (17 mg/kg/day) significantly inhibited the decrease in these bone parameters, especially in tibiae, and completely inhibited the decrease in urinary Gla content. In experiments 2 and 3, prednisolone (10 mg/kg), dissolved in cottonseed oil, was given to rats intramuscularly three times a week for 4 and 10 weeks, respectively. In experiment 2, bone length, bone strength and calcium content in the femur were reduced by 4-week prednisolone treatment. These reductions were significantly improved by menatetrenone (21 mg/kg/day). In experiment 3, 10-week prednisolone treatment reduced bone length and the calcium and hydroxyproline content of the femur. Menatetrenone (0.4, 10, and 50 mg/kg/day) significantly inhibited the reduction of calcium content in the femur. These results suggest that menatetrenone may inhibit the bone loss induced by corticosteroid treatment.

Animals↗
PubMedDate not supplied

Spermicidal activity of menfegol-coated condom.

The spermicidal activity of menfegol-coated condoms was investigated. Menfegol (P-menthanyl-phenyl-polyxyethylene [8,8] ether) showed strong spermicidal activity at 0.5 mg/ml and higher concentrations. Semen was ejaculated directly into menfegol-coated condoms (20 mg/condom) or uncoated condoms. Immediately after ejaculation, sperm motility and viability were examined. In the menfegol-coated condoms, sperm motility was completely suppressed and no viable sperm were observed. In the uncoated condoms, most of the sperm were alive, although their motility was almost suppressed. These results indicate that the menfegol-coated condom represents a new birth control method in which the contraceptive efficacy of the condom is enhanced by the spermicidal activity of menfegol.

Contraceptive Devices, Male↗
PubMedDate not supplied

Mecobalamin promotes mouse sperm maturation.

The effect of Mecobalamin (alpha-(5,6-dimethyl benzimidazolyl)-Co-methyl-cobamide: Me-B 12) on sperm production in the oligozoospermic mice experimentally induced by the treatment with adriamycin (0.3 mg/kg, three times a week for 5 weeks) was evaluated quantitatively by means of equilibrium sedimentation in Percoll. After centrifugation, the distribution profile of the sperm showed two peaks, i.e. the first peak near the bottom consisting of mature sperm with good motility and the second peak containing immature and/or immotile sperm. By oral administration of Me B 12 (1.0 mg/kg/day) to the oligozoospermic mice for 10 weeks, the sperm count, sperm motility, motile sperm count, diameter of seminiferous tubules and the percentage of good motile sperm with higher apparent density were increased as compared with those of the control. These results suggest that Me-B 12 enhanced the testicular function, resulting in an increased output of mature sperm.

Animals↗