Biomedical subjects

K Hoshi

Publications and source records attributed to K Hoshi.

At least 199 records · Page 11Linked to original sources

PubMed1993

Oxygen demand-supply relationship in peripheral tissues as a therapeutic indicator in acute myocardial infarction with advanced heart failure.

Oxygen demand-supply relationships in peripheral tissues were studied in 14 patients who had acute myocardial infarction with advanced pump failure. Seven patients with acute myocardial infarction but without pump failure were studied as a control. In all patients, a Swan-Ganz catheter and a radial arterial cannula were inserted for the purpose of hemodynamic monitoring, and arterial and mixed venous blood were sampled. Initially, oxygen delivery (DO2) (p < 0.01) was lower, and oxygen extraction ratio (OER) (p < 0.001) and oxygen tension at 50% saturation (P50) (p < 0.01) were higher in patients with pump failure than in the controls. During the therapeutic course, with an increase in the cardiac index and DO2, oxygen uptake (VO2) did not change but OER (p < 0.001) and P50 (p < 0.01) significantly decreased in 6 survivors with pump failure. In contrast, an increased VO2 (p < 0.01) and no change of OER and P50 were observed in 8 nonsurvivors with pump failure. These results suggest that reversibility of oxygenokinetics might be an important factor for recovery from critical heart failure.

Aged↗

PubMed1993

Wound healing process in the portio vaginalis uteri after CO2-laser treatment.

In order to determine the would healing process in the portio vaginalis uteri, 3[H]-thymidine incorporation and hydroxyproline concentration in the granulation tissue were measured histochemically after CO2-laser treatment. As a result, the squamous epithelium showed the thymidine uptake in extended regions in the first week and in basel cell hyperplastic regions in the second week. The uptake was seen in the reserve cell hyperplastic regions of the epithelium from the 2nd week. Hydroxyproline concentration peaks mostly appeared within one week after the laser treatment. After cryosurgery, the peaks mostly appeared after two weeks or more. These results indicated that, the stromas and then the squamous and columnar epithelial cells in turn were regenerated after CO2-laser treatment, and that the regeneration occurred earlier after laser treatment than after cryosurgery.

Cervix Uteri↗

PubMed1993

Pharmacokinetics of succinylcholine in man.

The pharmacokinetics of succinylcholine (SCh) 1 or 2 mg/kg was studied in 14 anesthetized patients. Arterial blood concentrations of SCh were measured using a high-performance liquid chromatographic assay. The arterial concentration vs. time data were analyzed by log-linear regression and fitted to an one-compartment model. The pharmacokinetic parameters were (SCh 1, n = 8 and 2 mg/kg, n = 6): apparent volume of distribution (16.4 +/- 14.7 and 5.6 +/- 6.8 ml/kg, mean +/- S.D.), total body clearance (40.5 +/- 38.7 and 15.0 +/- 14.8 liter/min), area under the plasma concentration-time curve (124.3 +/- 163.2 and 695.3 +/- 1008.9 min.micrograms/ml), and elimination half-life (16.6 +/- 4.8 and 11.7 +/- 4.5 sec). The rapid disappearance of SCh from the blood may be due to diffusion out of the blood vessel.

Adult↗

PubMed1993

Review: recent advances in lipid microsphere technology for targeting prostaglandin delivery.

Although prostaglandin E1 (PGE1) and prostacyclin (PGI2) exhibit pharmacological activities in free form, it has been hypothesized and experimentally verified that carrier preparations can target them more effectively at lower doses, thus causing fewer side effects. Lipid microspheres (LM) with a diameter of 0.2 micron are drug carriers prepared from soybean oil and lecithin, and the drug is incorporated within the LM. Lipo-PGE1 and lipo-PGI2 are LM preparations of PGE1 and a PGI2 derivative that are designed to accumulate at the vascular lesions. The authors have achieved remarkable clinical effects against neuropathy and ulcers, severe hepatitis, congenital heart diseases, and acute cerebral thrombosis using these preparations. In this review, clinical observations, some basic studies including targeting delivery of lipo-PGE1 to the liver, and future indications for these preparations are introduced. Development of a new lipo-PGE1 (lipo-AS013) that overcomes the disadvantages of the preparation currently available is also discussed. Lipo-AS013, a prodrug of PGE1, is considered superior to free PGE1 in terms of its chemical stability in LM and the retention ratio of the drug in LM in the body.

Animals↗

PubMed1993

[Effect of continuous intravenous administration of midazolam and ketamine on respiratory pattern].

The purpose of the study was to investigate the effect of continuous IV administration of midazolam and ketamine on respiratory pattern in six adult volunteers. Midazolam 0.05 mg/kg and ketamine 0.5 mg/kg were given, and then 0.1 mg/kg/hr for midazolam and 1 mg/kg/hr for ketamine were administered continuously. We measured MV, RR and TV (OMR86036), and calculated duty ratio and mean inspiratory flow at the level of 0 and 5 cmH2O CPAP during spontaneous respiration of air with and without 5% CO2. Each parameter was obtained before and 1 hr after the start of IV administration of the drugs. With 5% CO2, MV decreased significantly from 15.5 +/- 1.5 l/min to 11.7 +/- 0.8 l/min at 0 cmH2O CPAP level and from 15.8 +/- 1.8 l/min to 12.6 +/- 1.5 l/min at 5 cmH2O CPAP level, and also mean inspiratory flow decreased significantly from 590 +/- 2 ml/sec to 421 +/- 30 ml/sec at 0 cmH2O CPAP level and from 606 +/- 53 ml/sec to 477 +/- 48 ml/sec at 5 cmH2O CPAP level. TV decreased significantly during sedation at both CPAP levels with or without 5% CO2, while RR and duty ratio tended to increase. It was thought that, when the respiration was stimulated with 5% CO2, the decrease in mean inspiratory flow greatly contributed to the fall in MV during administration of midazolam and ketamine.

Adult↗

PubMed1993

[Postoperative apnea in preterm infants after inguinal herniorrhaphy].

Preterm infants may become apneic during immediate postoperative period. We studied prospectively postoperative apneic attack in 167 preterm infants after inguinal herniorrhaphy with nitrous oxide-halothane anesthesia. Their mean gestational age was 30 +/- 3 weeks. The mean postnatal age at operation was 14 weeks. The post-conceptual age varied between 36 and 56 weeks. The mean birth weight was 1351 +/- 395 kg. Although many of them had a risk factor of postoperative apneic attack, i.e.a young post-conceptual age (less than 41 weeks), a light weight at operation (below 3000g), only one infant who had received emergency operation had an episode of apneic attack up to 2 postoperative days. For preventing postoperative apneic attack in preterm infants after inguinal hernia, we recommend the use of halothane anesthesia and the attention until a complete awakening.

Apnea↗

PubMed1993

[The bone mineral density change with aging of women and usefulness of single energy X-ray absorptiometry for measurement of bone mineral content].

The calcaneus bone mineral density of 473 women was measured by single photon absorptiometry (SPA) and the vertebrae bone mineral density of 198 women was measured by dual energy X-ray absorptiometry (DEXA). The calcaneus bone mineral density of women starts decreasing at age 30, and the rate of decrease accelerates after the age of 50. The vertebrae bone mineral density starts decreasing at the age of 35, and a conspicuous decrease can be seen after the age of 50 as well. Because bone deterioration of Japanese women is thought to start earlier than in Europeans and Americans, the necessity of osteoporosis screening before menopause was suggested. A high positive correlation (r = 0.804) between calcaneus bone mineral density and vertebrae bone mineral density was found, and a high degree of precision of SXA was shown.

Absorptiometry, Photon↗

PubMed1992

Androst-5-ene-7,17-dione: a novel class of suicide substrate of aromatase.

5-En-7-one steroid 1 was found to be a potent inhibitor of aromatase. This along with its 19-hydroxy derivative 7 was characterized as suicide substrate of human placental aromatase (k(inact)'s of 0.069 and 0.058 min-1 and KI's of 143 nM and 11.1 microM, respectively, for steroids 1 and 7). The results suggest that the 19-oxygenation would be involved in the irreversible inactivation of aromatase by the 5-en-7-one steroids.

Androstenedione↗

PubMed1992

Recognition of an antiparallel beta-sheet structure of human epidermal growth factor by its receptor. Site-directed mutagenesis studies of Ala-30 and Asn-32.

The Ala-30 and Asn-32 residues involved in the major antiparallel beta-sheet structure of human epidermal growth factor (hEGF) were substituted with various amino acid residues, and the receptor-binding affinities of the nine variant hEGFs were determined by the use of human KB cells. The Ala-30----Arg, Ala-30----His and Ala-30----Phe substitutions drastically reduced the binding affinity, suggesting that the side chain in position 30 of Ala-30 of hEGF is required to be small for the receptor binding. The Asn-32----Asp substitution significantly reduced the binding affinity, while the Asn-32----His variant could bind to the receptor as well as to the wild-type hEGF. Therefore, it seems to be important for receptor binding that the side chain in position 32 does not have a negative charge but does have an NH group. Thus, we propose that, in the ligand-receptor complex, the receptor recognizes, on one side of the antiparallel beta-sheet structure of hEGF, a wider contact area than previously suggested.

Alanine↗

PubMed1992

A site-directed mutagenesis study on the role of isoleucine-23 of human epidermal growth factor in the receptor binding.

The isoleucine-23 residue of human epidermal growth factor (hEGF) was substituted by a variety of amino acid residues and the receptor-binding activities of variant hEGFs were determined by the use of human KB cell. Tight receptor binding was found of variants with hydrophobic amino acid residues in position 23. The size of the isoleucine residue was nearly optimum for the receptor binding as compared with other hydrophobic residues. The structure analysis by two-dimensional nuclear magnetic resonance spectroscopy showed that the substitution at position 23 only slightly affected the tertiary structure of hEGF. These indicate that the side chain of isoleucine residue in position 23, which is exposed on the protein surface, directly binds to a hydrophobic pocket of the receptor.

Amino Acid Sequence↗

PubMed1992

Pretreatment of hamster oocytes with Ca2+ ionophore to facilitate fertilization by ooplasmic micro-injection.

The fertilization rate after ooplasmic micro-injection in mammals is low. In hamsters, micro-injection of sperm nuclei into oocytes resulted in the release of the second polar body and the formation of female and male pronuclei, but disappearance of the cortical granules was minimal. These unfavourable results seem to be associated with insufficient activation of oocytes by the current techniques of micro-injection. Therefore, we attempted to increase the fertilization rate by pretreating the oocytes with a Ca2+ ionophore, A23187 (10 microM, 3 min). Sperm nuclei were then micro-injected into the treated oocytes and 5 h later the percentage of oocytes at the pronuclear stage was examined: 53.1% for untreated controls and 85.7% for the treated group (P less than 0.05). However, when the number of pronucleate oocytes was divided by the number of A23187-activated oocytes, the percentage was 81.0% for the controls and 85.7% for the treated group. These findings suggest that pretreatment of oocytes with ionophore does not facilitate fertilization of activated oocytes, but that it indirectly enhances their development to the pronuclear stage by increasing the efficiency of egg activation.

Animals↗

PubMed1992

Difference between effects of chlorpromazine and perphenazine on microsomal phospholipids and enzyme activities in rat liver.

The effects of acute administration of chlorpromazine (CPZ) and perphenazine (PPZ) on hepatic microsomal phospholipids (PLs) and enzyme activities in the male rat were examined in order to elucidate the relationship between individual PLs and drug-metabolizing activity. Cytochrome P-450 and aniline (AN) hydroxylation activity were initially decreased in CPZ-treated rats, but cytochrome P-450 subsequently recovered to a level not significantly different from the control and AN hydroxylation was markedly increased, while in PPZ-treated rats, they remained depressed. CPZ increased the activities of glycerophosphate acyltransferase (GPA) and choline phosphotransferase (CPT), while PPZ increased the activities of phosphatidate cytidylyltransferase (PCT), phosphatidate phosphohydrolase (PPH) and CPT. Concurrently, CPZ raised microsomal phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine-inositol (PSI) and sphingomyelin (SM), while PPZ increased PC and PE, but did not affect the levels of PSI and SM. Acyl components of phospholipids were also modified. CPZ significantly decreased the ratio of saturated to unsaturated fatty acids, particularly in the PC and PE fractions, while the effect of PPZ was only slight. The results imply that an increase of AN hydroxylation activity may involve the incorporation of unsaturated fatty acids into enzyme-associated PC and PE.

Aniline Hydroxylase↗

PubMed1992

[A case of angina pectoris with cardiac arrest at treadmill stress test].

We reported a case of angina pectoris with cardiac arrest immediately after treadmill exercise test, and the effect of PTCA in the same case. A 69-year-old Japanese male had chest oppression on exertion. Initial treadmill test showed 2 mm ST-segment depression in leads V4-6. Two minutes after exercise, he had atrio-ventricular (A-V) block and cardiac arrest with episodes of fainting. He was resuscitated by chest thump. Coronary angiography showed 90% stenosis in the right coronary artery (RCA). PTCA for RCA was able to dilate the stenotic lesion. The second treadmill test after PTCA did not induce bradycardia nor A-V block. It was suggested that the RCA lesion may play a critical role.

Aged↗

PubMed1992

Increased peripheral blood gamma delta+ T cells and natural killer cells in Behçet's disease.

Peripheral blood cytotoxic lymphocytes, including gamma delta+ T cells, natural killer (NK) cells, and CD56+ T lymphocytes were investigated by using 2-color flow cytometry in patients with Behçet's disease. The percentage of circulating gamma delta+ T cells among total lymphocytes or among total T cells was significantly increased in patients with Behçet's disease, compared to healthy controls. An increase in circulating gamma delta+ T cells was related to mucocutaneous lesions, but not the HLA-B51. Among gamma delta+ T cells, the number of CD8+ or CD56+ subset was significantly increased in patients with Behçet's disease. Moreover, significant increases of peripheral blood NK cells (CD16+CD56+CD3-, CD2+CD3-, CD8dim+CD3-) and CD56+ T lymphocytes were also observed. Our data suggest that increased circulating gamma delta+ T cells and NK cells may play an important role in the pathogenesis of Behçet's disease.

Adult↗

PubMed1992

[Perioperative management of uvulopalatopharyngoplasty for the obstructive sleep apnea patient].

The perioperative courses of 10 patients with obstructive sleep apnea syndrome who underwent uvulopalatopharyngoplasty were reported. No hypnotic was administered at night before operation. Premedication consisted of atropine 0.5 mg, meperidine 35 mg, given i.m. 1 hr prior to surgery. No patients developed respiratory depression after premedication. General anesthesia was induced with iv thiopental, and succinylcholine was given to facilitate tracheal intubation. Airway management was technically difficult in all patients. Anesthesia was maintained with N2O-O2-enflurane under controlled ventilation. At the end of the surgery the insertion of a nasopharyngeal airway was performed for the prevention of airway obstruction. In 8 patients it was possible to remove the airway in the next morning. Dexamethasone was administered 3 times to reduce pharyngeal edema during perioperative period. Trachea was extubated when the patient was fully awake and alert. Perioperatively the following points are important in the management of uvulopalatopharyngoplasty. 1. Assessment of airway and the method of airway control. 2. Reduction of pharyngeal edema. 3. Using caution against the postoperative hemorrhage. 4. Avoidance of sedation. 5. Close observation extending into the postoperative period.

Adult↗

PubMed1992

[Effect of cervical mucus on zona induced acrosome reaction of human spermatozoa].

Zona induced acrosome reaction of human spermatozoa was examined by FITC labelled PSA staining. When human spermatozoa were incubated with salt stored human eggs for 6 hours, the percentage of acrosome reacted spermatozoa was 35.7 +/- 17.7%. The zona induced acrosome reaction rate was significantly higher than that of the spontaneous acrosome reaction (2.8 +/- 1.9%). These date indicate that the zona pellucida of the human egg have the ability to induce the acrosome reaction as in other mammalian zona. Additionally the effect of cervical mucus on the acrosome reaction was examined. Spermatozoa which passed through the cervical mucus were collected and examined for the rate of spontaneous and zona induced acrosome reaction. The rate of spontaneous acrosome reaction was almost the same as the control, but the rate of zona induced acrosome reaction (51.6 +/- 6.8%) was significantly higher than that of the control (25.6 +/- 9.4%). These data suggest that spermatozoa appear to complete capacitation by passing through cervical mucus.

Acrosome↗

PubMed1991

Is focal chronic autoimmune thyroiditis an age-related disease? Differences in incidence and severity between Japanese and British.

The incidence of chronic lymphocytic thyroiditis in autopsy material from Japanese and British subjects was evaluated. Lymphocytic infiltration in representative thyroid sections from 1826 Japanese cases collected from four different institutions was analysed. The overall incidence of lymphocytic infiltration was significantly higher in females (22.2 per cent) than in males (13.9 per cent). In females, the incidence reached 23.2 per cent in the fourth decade and showed no increase with age thereafter. The overall incidence of lymphocytic infiltration in thyroid sections from 810 British cases was 42.5 per cent in females and 19.4 per cent in males; an increase in the incidence of thyroiditis from the sixth decade onwards was noted in British females, the figure reaching 50.0 per cent in those aged over 70 years. These findings suggest possible racial differences in susceptibility to chronic thyroiditis. The disorder is not necessarily related to age, increasing severity of disease with age being found only in British females.

Adult↗

PubMed1991

A time-dependent inactivation of aromatase by 19-oxygenated androst-4-ene-3,6,17-triones.

19-Hydroxyandrost-4-ene-3,6,17-trione (19-OHAT), its 19-oxo derivative (19-oxo AT) and 4 beta, 5 beta-epoxyandrostane-3,6,17-trione (5) were synthesized as possible intermediates involved in a mechanism-based inactivation of aromatase caused by androst-4-ene-3,6,17-trione (AT). These compounds, inhibited the enzyme in a competitive manner with Ki's of 0.61, 7.5 and 5.1 microM for 19-OHAT, 19-oxo AT, and compound 5. The two 19-oxygenated steroids showed a time-dependent, pseudo-first order rate of inactivation of aromatase with kinact's of 0.222 and 0.076 min-1 for 19-OHAT and 19-oxo AT, respectively, while compound 5 did not. NADPH and oxygen were required for the inactivation. Androstenedione blocked the inactivation, while L-cysteine partially prevented that of 19-OHAT and almost completely that of 19-oxo AT. When the 19-oxygenated steroids were separately subjected to reaction with N-acetyl-L-cysteine, these rapidly disappeared from the reaction mixture with t1/2 of 25 min (19-OHAT) and 20 s (19-oxo AT). This finding indicates that L-cysteine prevents inactivation by a chemical dependent elimination of the inhibitors from the incubate. These results suggest that the 19-oxygenation rather than the 4,5-epoxidation may be involved in the time-dependent inactivation by AT.

Androstenols↗