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Biomedical subjects

K Hoshi

Publications and source records attributed to K Hoshi.

At least 217 records · Page 12Linked to original sources
PubMed1991

Synthesis and biochemical studies of 16- or 19-substituted androst-4-enes as aromatase inhibitors.

Androst-4-en-17-one derivatives [19-acetoxide 4, 16-bromides 14 and 15, 19,19-difluoride 18, and (19R,S)-19-acetylenic alcohol 25] and androst-4-en-17 beta-ol derivatives 3, 5, 10, 12, and 19 were synthesized and tested for their ability to inhibit aromatase in human placental microsomes. All the 17-oxo steroids, except compound 25 and 17,19-diol 3 of this series, were effective competitive inhibitors with apparent Ki's ranging from 170 to 455 nM. 19,19-Difluoro steroid 18 and 19-acetylenic alcohol 25, a weak competitive inhibitor (Ki = 7.75 microM), caused a time-dependent, pseudo-first-order inactivation of aromatase activity with kinact's of 0.0213 and 0.1053 min-1 for compounds 18 and 25, respectively. NADPH and oxygen were required for the time-dependent inactivation, and the substrate, androst-4-ene-3,17-dione, prevented it, but a nucleophile, L-cysteine, did not in each case. The results strongly suggest that aromatase would attack the 19-carbon of steroids 18 and 25.

Androstenes↗
PubMed1991

Nitroglycerin-induced transient coronary artery occlusion.

Nitroglycerin induced a paradoxical disappearance of a stenosed coronary artery in a 57-year-old man with non-Q wave myocardial infarction. On the coronary angiogram, the left anterior descending coronary artery (with a 95% stenosis) became completely invisible 2 min after 0.3 mg sublingual nitroglycerin. Three minutes later, the artery was opacified again. This transient occlusion may have resulted from a passive collapse of the distal portion of the artery, due to insufficient access of nitroglycerin across the stenotic region.

Animals↗
PubMed1991

Aortic dissection associated with aortitis syndrome.

A 50-year-old woman with aortitis syndrome complicated by aortic dissection, is reported. The dissection was observed at the level of the descending thoracic aorta by aortography and at the intimal side of the dilated aorta on CT. An aneurysm of the right subclavian artery and a diffusely thick wall of the abdominal aorta were also observed. This case suggests that the uneven wall of the aorta in aortitis syndrome might be dissected at the intimal side by dilatation.

Aneurysm↗
PubMed1991

Importance of Ca2+, K+ and glucose in the medium for sperm penetration through the human zona pellucida.

When salt-stored human oocytes were inseminated in the regular mBWW medium and examined 6 hr later, the zonae of almost all of the oocytes were penetrated by spermatozoa. In contrast, none of zonae were penetrated when the oocytes were inseminated in either Ca(2+)-free, K(+)-free or glucose-free medium. The failure of zona penetration by spermatozoa in Ca(2+)-free and K(+)-free media is likely to be due to the inhibition of the acrosome reaction. Spermatozoa were unable to exhibit hyperactivated motility in glucose-free medium, suggesting that the failure of zona penetration in this medium is due, at least in part, to the inhibition of hyperactivated motility of spermatozoa.

Calcium↗
PubMed1991

[An X-ray study of catheters abnormally placed in the epidural space].

We investigated the roentgenogram of the epidural catheter in 82 patients in whom the injection of local anesthetics had no effect. Contrast medium 0.5 ml was injected through the epidural catheter and antero-posterior roentgenogram was taken. The roentgenograms were categorized into three patterns, according to the relationship of the catheter to the pedicle of lamina, or to the spread of contrast medium. In 43 cases, the catheter passed through the intervertebral foramen. The tip of the catheter was located outside the foramen, and the contrast medium spread outside the vertebra. In 4 cases, the tip of the catheter was located laterally in the vertebral column, and only the catheter itself was contrasted but no spread of medium was observed. The catheter was thought to be misinserted intravascularly. In other 35 cases, catheter ran laterally on the pedicle of lamina, or the spread of medium 2 mins after the injection was indicated by a dumpling-shape even when the tip was in the vertebral column. In these cases, the catheter was thought not to be outside the epidural space.

Anesthesia, Epidural↗
PubMed1991

Topical application of superoxide dismutase cream.

A superoxide dismutase (SOD) cream containing 0.6 mg/ml of bovine SOD was prepared. It was applied locally onto the skin and mucosal lesions caused by progressive systemic sclerosis (PSS), systemic lupus erythematosus (SLE), Behçet's disease, herpes simplex and burns. The lesions and symptoms were rapidly improved in many cases after its administration, even when the symptoms were stabilized for several weeks before the treatment. Although the trial was open-labelled, the topical application of SOD was concluded to be effective for these conditions.

Administration, Topical↗
PubMed1990

Synthesis of 3 beta,16 beta,19-trihydroxyandrost-5-en-17-one and 16 beta,19-dihydroxyandrost-4-ene-3,17-dione and their 19-oxo derivatives.

3 beta,16 beta,19-Trihydroxyandrost-5-en-17-one (12) was synthesized from 5 alpha-bromo-3 beta-acetoxy-6 beta,19-epoxyandrostan-17-one (2) through acetoxylation at C-16 beta of the enol acetate 4 with lead tetraacetate and reductive cleavage of the epoxide ring with zinc dust yielding the 3 beta,16 beta-diacetoxy-19-hydroxy steroid 11, followed by hydrolysis of the acetoxy groups with sulfuric acid. Jones oxidation of compound 11 followed by the acid hydrolysis gave the 19-oxo steroid 15. 5 alpha-Bromo-3 beta-hydroxy-16 beta-acetoxy-6 beta,19-epoxyandrostan-17-one (8), obtained by selective hydrolysis of the 3-formate 5 with ammonium hydroxide, was oxidized with Jones reagent to afford the 3-oxo steroid 16, which was converted into the 19-hydroxy derivative 17 by treatment with zinc dust. 16 beta,19-Dihydroxyandrost-4-ene-3,17-dione (18) and its 19-oxo derivative 21 were obtained from compound 17 through a similar reaction sequence.

Androstenedione↗
PubMed1990

A preliminary double-blind cross-over trial of lipo-PGI2, a prostacyclin derivative incorporated in lipid microspheres, in cerebral infarction.

Lipo-PGI2 is a drug preparation of a PGI2 analogue (isocarbacyclin methylester) which is incorporated into lipid microspheres with a diameter of 0.2 mu. Lipo-PGI2 has been shown to accumulate at the vascular wall, particularly those of arteriosclerotic lesions, and it has a much stronger inhibitory activity on platelet aggregation than free isocarbacyclin. In this study, a preliminary double-blind cross over trial of lipo-PGI2 in cerebral infarction was carried out. Seventeen patients with chronic cerebral infarction received 2 micrograms of lipo-PGI2 and placebo daily for one week each in a cross-over double blind test. A significant improvement was noted for lipo-PGI2 compared with placebo in the overall improvement in neurological and mental symptoms (p less than 0.01). The patient's preference also indicated the effectiveness of lipo-PGI2 (p less than 0.05). Adverse reactions were noted in 3 patients receiving placebo, but not in any receiving lipo-PGI2. These results show that lipo-PGI2 at a very low dose would be beneficial as a treatment for relieving the clinical symptoms of chronic cerebral infarction and that lipid microspheres are a useful drug carrier for PGI2 analogue therapy.

Adult↗
PubMed1990

Variation in the cholesterol/phospholipid ratio in human spermatozoa and its relationship with capacitation.

The cholesterol/phospholipid (C/PL) ratio was determined for spermatozoa from eight men with normal semen parameters. There was a close correlation between the C/PL ratio and the rate of sperm capacitation as assessed by the hamster egg penetration test. A lower C/PL ratio correlated with a faster capacitation time. This supports the notion that the loss or reduction of membrane cholesterol constitutes an important step of capacitation in human spermatozoa.

Adult↗
PubMed1990

Automated semen analysis shows an increase in sperm concentration and motility with time in Makler chambers having excess sample volume.

The sperm concentration and motility within a Makler chamber increased markedly after 3-5 min of settling when one large drop (approximately 24 microliters) of semen was loaded in the chamber. The values remained stable when a 5-microliter volume was loaded and were intermediate with a 10-microliter volume. In order to obtain accurate data, it is necessary to load the Makler chamber with a semen volume of no more than 5 microliters.

Automation↗
PubMed1990

Malignant eccrine tumor--a case report and a classification of tumors of eccrine sweat apparatus.

A case of malignant eccrine tumor and its histological findings were reported. In this case, we considered basal cell carcinoma or malignant melanoma clinically; however, the histological features matched those of malignant eccrine tumor. It has been said that it is very difficult to determine the origin of tumors of sweat apparatus; to contribute to this ongoing dialogue, the classification of tumors of eccrine sweat apparatus was also discussed.

Adult↗
PubMed1990

Synthesis of 16 alpha-hydroxyandrost-4-ene-3,17,19-trione and 3 beta, 16 alpha-dihydroxyandrost-5-ene-17,19-dione; potential intermediates of estriol biosynthesis.

16 alpha-Hydroxyandrost-4-ene-3,17,19-trione (10) was synthesized from the 16 alpha-hydroxy-6 beta,19-epoxy-17-one 3 via protection of the 16 alpha-hydroxy function as its tert-butyldimethylsilyl ether or acetate. Reductive cleavage of the epoxy ring of the silyl ether 4 or the acetate 5 with zinc dust gave the 19-alcohol 6 or 7, which was treated with pyridinium dichromate or Jones reagent, respectively, and then hydrolyzed with diluted sulfuric acid, yielding the desired steroid 10. 3 beta,16 alpha-Dihydroxyandrost-5-ene-17,19-dione (14) was also synthesized from 5 alpha-bromo-3 beta,16 alpha-diacetoxy-6 beta, 19-epoxyandrostan-17-one (11) through the intermediates 12 and 13 with the 3 beta- and 16 alpha-hydroxy functions protected as their acetates in a reaction sequence similar to that above.

Androstenediols↗
PubMed1990

Effect of amitriptyline or phenobarbital on the activities of the enzymes involved in rat liver.

The effect of phenobarbital (PB) or amitriptyline (AMT) on phospholipid metabolism was studied in rat liver. Administration of PB or AMT caused a marked increase in the microsomal phosphatidylcholine (PC) content. In this context, the activities of glycerophosphate acyltransferase (GAT), phosphatidate cytidylyltransferase (PCT), phosphatidate phosphohydrolase (PPH) and choline phosphotransferase (CPT) in the liver were all increased by PB. In contrast, the activities of GAT and PCT were little affected by AMT, while those of PPH and CPT were significantly increased by AMT. These findings suggest that AMT or PB would increase hepatic microsomal PC synthesis through inducing PPH and then CPT.

Amitriptyline↗
PubMed1990

[Changes in arterial oxygen tension during and after enflurane or halothane anesthesia as well as epidural analgesia].

Recovery from inhalation anesthesia is often marked by the occurrence of postoperative hypoxemia. In this study, we compared the effects of enflurane or halothane anesthesia and epidural analgesia on arterial oxygen tension during and after the operation in 60 ASA physical status 1-2 patients who underwent cholecystectomy. Anesthesia was induced with thiopental and maintained with 66% N2O and -enflurane (1.5%), -halothane (1%), or -epidural lidocaine (1% solution, 17.5 ml) in oxygen. Blood gas analysis was done before and 10, 30, 60 min after induction. PaO2 was measured on 1st and 3rd postoperative days in all patients breathing air spontaneously. PaO2 decreased during operation in all three groups of anesthesia. PaO2 values on first postoperative day were significantly lower than those before operation, and PaO2 value in enflurane group (PaO2 = 67 +/- 1 mmHg) was significantly lower than that in halothane group (PaO2 = 72 +/- 2 mmHg, P less than 0.05).

Adult↗
PubMed1990

[Apnea and oxygen desaturation following nitrous oxide inhalation].

Apnea and desaturation following nitrous oxide inhalation were studied in seven adult volunteers breathing spontaneously. Arterial oxygen saturation (SpO2), end-tidal CO2 concentration in the nasal cavity and respiratory patterns were measured in volunteers breathing air after N2O (50% or 67%) + O2. SpO2 was measured with Biox 3700 and end-tidal CO2 concentration was measured with Normocap, and respiratory patterns were recorded with RESPIGRAPH. After breathing N2O, two volunteers had frequent apnea (greater than 20 sec) accompanied by desaturation (SpO2 less than 90%). The lowest value of SpO2 was 82%. When the apnea occurred, the airway seemed to be open and end-tidal CO2 concentration values were lower than those before N2O inhalation. The authors considered that this kind of apnea was due to several factors, such as hypocapnia caused by hyperventilation during N2O anesthesia, dilution of alveolar O2 and CO2 during N2O excretion, loss of consciousness by N2O, and depression of CO2 ventilatory response by N2O. Inhalation of O2 at high concentrations for five minutes could improve the hypocapnia and prevent the apnea.

Adult↗