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Biomedical subjects

Y Higashi

Publications and source records attributed to Y Higashi.

At least 325 records · Page 18Linked to original sources
PubMed1986

Semisynthetic beta-lactam antibiotics. I. Synthesis and antibacterial activity of 7 beta-[2-aryl-2-(aminoacetamido)acetamido]-cephalosporins.

The synthesis and in vitro structure-activity relationships of cephalosporins having dipeptides substituted with various aryl groups as the side chain at the C-7 position have been outlined. Of these compounds, 2-aminothiazol derivatives showed a broad spectrum of enhanced antibacterial activity, and 7 beta-[DL-2-(D-aminopropionamido)-2-(2-aminothiazol-4-yl)acet amido]-3- [(1-methyl-1H-tetrazol-5-yl)thiomethyl]ceph-3-em-4-carboxyli c acid was the most balanced of these active derivatives with respect to both Gram-positive and Gram-negative strains.

Bacteria↗
PubMed1985

Changes of chromatin conformation around mouse interferon-beta gene associated with induction of interferon synthesis.

Changes of chromatin structure around the mouse interferon-beta gene associated with induction were examined by the use of sensitivity to digestion with DNaseI. Upon induction, the DNaseI-sensitivity of mouse interferon-beta gene was increased and seven DNaseI-hypersensitive sites were mapped. One of them, which was located at approximately 100bp upstream and was insensitive in the uninduced state, showed a marked sensitivity upon induction. Four others, located at 580bp and 430bp upstream, and 1.9kb and 2.2kb downstream, whose levels of DNaseI-sensitivity were very low in the uninduced state, showed significant sensitivity in the induced state. Two remaining sites, located at 7.5kb upstream and 7.6kb downstream, had relatively high DNaseI-sensitivities even in the uninduced state and slightly increased their sensitivities upon induction.

Animals↗
PubMed1985

Enhanced rectal absorption of sodium ampicillin by N-acyl derivatives of collagen peptide in rabbits and rats.

The promoting effect of N-acyl derivatives of a collagen peptide which was fractionated from the hydrolysates of collagen on the rectal absorption of sodium ampicillin was studied. An increase in the blood level of ampicillin was observed in rabbits and rats following the administration of a sodium ampicillin suppository containing N-octanoyl(C8-CP), decanoyl(C10-CP), dodecanoyl(C12-CP), and stearoyl(C18-CP) derivatives of collagen peptide. The most efficient action was observed in the suppository containing C18-CP. Some factors influencing the promoting effect of the adjuvants on the rectal absorption of sodium ampicillin from solution were also studied in rats using in situ perfusion method and loop method. The promoting effect of the adjuvants on the rectal absorption of sodium ampicillin was markedly increased in the hypertonic solution. The promoting effect was also suppressed by the addition of calcium chloride to the solution administered to the rectal loop or to the perfusate in the in situ perfusion method. These results suggest that the tight junction of the epithelia of the rectum will be markedly influenced by the presence of the adjuvants, especially in the hypertonic solution. The adjuvant interaction with the calcium ions located in the rectal membrane may be involved in the enhanced absorption of sodium ampicillin.

Ampicillin↗
PubMed1985

Studies of the human testis. XX--Effect of NADH on 17 alpha-hydroxypregnene C17-20 lyase activity.

A study of the cofactor requirements of C17-20 lyase was carried out using human testis tissue obtained at the time of orchiectomy for treatment of prostatic carcinoma. Washed microsomal fractions were prepared from frozen human testes using a KCl containing buffer. The preparation revealed dose-dependent activity of C17-20 lyase in the presence of either NADPH or commercial or purified NADH. The Km of NADH for the enzyme was of the order of 10(-3) M and the Km of NADPH was determined as 1.6 X 10(-5) M. NADH also provided synergistic enhancement of NADPH-mediated lyase activity, and decreased the Km of NADPH for the lyase but did not change the Vmax of NADPH-mediated lyase activity. Carbon monoxide inhibited both NADH and NADPH-mediated lyase activities indicating that both activities are catalyzed by cytochrome P-450. Cations including Ca2+, Mg2+ and Mn2+ were found to inhibit the NADPH-mediated lyase activity but enhanced the lyase activity in the presence of NADH. The results indicate both the presence of NADH-mediated C17-20 lyase activity and the synergistic effect of NADH on NADPH-mediated lyase activity in the human testis.

Aged↗
PubMed1985

An analysis of the age-related decline in testicular steroidogenesis in the rat.

The effect of aging in rats on serum and intratesticular testosterone levels, microsomal steroidogenic enzyme activities and microsomal cytochrome P-450 was studied. Serum testosterone levels were highest in 11-wk-old rats, declined at age 16 wk and further declined between ages 7 and 21 mo. Intratesticular testosterone levels in 21-mo-old rats were significantly lower than those of the other groups. The activity of 17 alpha-hydroxylase and C17-20 lyase, as well as cytochrome P-450, decreased significantly in 21-mo-old rats. The activity of 17 beta-hydroxysteroid oxidoreductase increased from 11 wk to 16 wk of age and then declined by 21 mo of age to the levels of 11-wk-old animals. Similar changes in delta 5-3,3-hydroxysteroid dehydrogenase coupled with delta 5-delta 4 isomerase activities were observed, but were not statistically significant. These results suggest that the decline in testosterone production in old rats is predominantly a result of decreased oxygenase activity. Inasmuch as oxygenases are gonadotropin dependent, our results support the hypothesis that gonadotropin deficiency is the major factor responsible for Leydig cell dysfunction in old rats. Further, the decline in the ratio of 17 alpha-hydroxylase to C17-20 lyase with aging suggests that other factors affect these enzymes as well as the reduction in cytochrome P-450.

Aging↗
PubMed1985

Enhanced rectal absorption of beta-lactam antibiotics in rat by monodesmosides isolated from pericarps of Sapindus mukurossi (Enmei-hi).

Monodesmosides, saponin A,B and C, isolated from pericarps of Sapindus mukurossi (Enmei-hi) were shown to promote the rectal absorption of beta-lactam antibiotics in rat, using an in situ loop method and an in vivo method. In the in situ loop method, monodesmosides were solubilized with a mixture of bisdesmosides, mukurozi-saponin X, Y1 and Y2, each of which was isolated from pericarps of Sapindus mukurossi. The promoting functions of the three monodesmosides for the rectal absorption of antibiotics were comparable and also suppressed by Ca2+ ion coexisting in the administered solution. Unlike the case of N-acylcollagenpeptides, which were also previously reported as absorption promoters, no influence of osmolarity of the administered solution on the absorption promoting action was observed. Absorption of beta-lactam antibiotics from suppositories was enhanced with the aid of either of monodesmosides without solubilizing agent.

Animals↗
PubMed1985

Sonographic diagnosis of bicameral gallbladders: a report of three cases.

Three cases of bicameral gallbladder are reported; the fundal chamber could be visualized by oral cholecystography in only one of these cases. However, all structures were well visualized sonographically. Ultrasonography is thus regarded as essential for the diagnosis of bicameral gallbladders and for detecting any calculi within them.

Aged↗
PubMed1985

[Percutaneous renal cyst puncture].

Ultrasound-guided renal cyst puncture was performed on 31 cysts which were then 95% ethanol instilled to prevent recurrence of cystic fluid. Ethanol was allowed to remain in place for 20 minutes and removed through the catheter. Morphological improvement was observed on IVP and Tc-99m-DMSA renal scintigram, and DMSA renal uptake rate increased slightly. The cystic wall became thicker, and cystic fluid did not remain any more. The renal tissue near the cyst was intact. One third of the patients had hotflush and/or somewhat drunken sense but these symptoms were only temporary. This method of therapy is a safe and effective way of treating renal cysts.

Adult↗