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Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 757 records · Page 42Linked to original sources
PubMed1987

Estimation of interaction function gamma(x) with sparsely ionizing radiation.

The interaction function gamma(chi), which was introduced in the theory of dual radiation action as the probability that two energy transfers separated by distance chi combine with each other to produce a lesion, was estimated with sparsely ionizing radiation (60Co gamma rays and 40 kV X rays). Gamma(chi) was deduced on the assumption that the sensitive matrix is made up of small spherical flocculi distributed over the cell nucleus. The diameter of a flocculus was estimated at (4.0-11.2) X 10(-8) m when the diameter of the cell nucleus d was assumed to be 5 microns, and (4.0-11.4) X 10(-8) m when d was assumed to be 10 microns. It seems reasonable to hypothesize that the flocculus corresponds to the linker DNA in the chromatin structure of DNA, because the size of the linker DNA as a target (about 40 nm) is consistent with the diameter of flocculi obtained in this study.

Animals↗
PubMed1987

[Clinical evaluation on the usefulness and safety of norfloxacin in a twice-a-day regimen against upper respiratory tract infections].

Sixty-six patients with tonsillitis or pharyngolaryngitis received oral norfloxacin (NFLX) 200 mg b.i.d. or 300 mg b.i.d. for not less than 3 days in general at School of Medicine, Yokohama City University, and 6 related hospitals. The results are summarized as follows: 1. Ten patients were excluded from the study because 4 patients did not present at the follow-up visits, 4 patients did not follow the protocol and 2 patients had unclear infections. Thus, 56 patients were evaluated. 2. The fifty-six evaluable patients were classified as follows: Twenty patients were with tonsillitis and 36 were with pharyngolaryngitis. Thirty-eight patients were treated with 200 mg b.i.d. while 18 patients received 300 mg b.i.d. Thirty-two patients were male and 24 patients were female. Three patients were inpatients and 53 patients were outpatients. Most of patients were light or moderate cases, and the 26 patients had mild underlying disorders. 3. Clinical improvements were observed in 11 of 15 patients (73.3%) with tonsillitis and 25 of 30 patients (83.3%) with pharyngolaryngitis (80.0% overall) within 7 days administration. 4. Clinical improvements were observed in 15 of all 20 patients (75.0%) with tonsillitis and 30 of all 36 patients (83.3%) with pharyngolaryngitis (80.4% overall). 5. Bacteriologically, "eradication", "decrease" and "replacement" were observed in 6, 2 and 1 patients, respectively. 6. As for adverse effects, nausea and headache were observed in 1 patient and abnormal changes in laboratory findings were noted in 1 patient (slight elevations of GOT and GPT). 7. Oral NFLX 200 mg b.i.d. or 300 mg b.i.d. was as almost equally effective as 200 mg t.i.d. in tonsillitis or pharyngolaryngitis. Thus NFLX 200 mg b.i.d. or 300 mg b.i.d. appears to give sufficient clinical efficiency. 8. When antibacterial activity and serum half-life of NFLX are considered, twice daily administration was confirmed to be sufficiently effective in the clinical application.

Adolescent↗
PubMed1987

[Mechanism of exercise-induced hyperuricemia].

This study was designed to make clear why increases and decreases in serum uric acid levels after vigorous exercise were delayed. Eight healthy male subjects who were given allopurinol before exercise participated in this study. We performed exhaustive exercise test on bicycle ergometer, and investigated the changes in purine metabolites levels in blood and urine. Results were summarized as follow; 1) Serum uric acid concentrations did not change significantly. Urinary excretions of uric acid decreased from 30 minutes to 1 hour after exercise, and recovered thereafter. 2) Plasma oxypurines concentrations exhibited the maximum level at 1 hour after exercise, and maintained the higher levels until 7 hours after exercise. Urinary oxypurines excretions exhibited the maximum level at 1 hour after exercise, and maintained the higher levels until 24 hours after exercise. 3) Plasma inosine concentrations increased only in one subject. Plasma hypoxanthine concentrations increased significantly in all subjects. Plasma xanthine concentrations did not change. 4) Blood ammonia concentrations exhibited the maximum level at 5 minutes after exercise, and returned to basal levels at 2 hours after exercise. These observations suggest that the delays of increases and decreases in serum uric acid levels are due to that the prolonged release of hypoxanthine from skeletal muscle lead to the prolonged production of uric acid in liver.

Adult↗
PubMed1986

Hyaluronic acid is an endogenous inducer of interleukin-1 production by human monocytes and rabbit macrophages.

When human peripheral monocytes and rabbit peritoneal macrophages were incubated with hyaluronic acid, the media were found to contain interleukin-1 (IL-1) activity and to stimulate collagenase production by rabbit fibroblasts. A digestion of hyaluronic acid by testicular hyaluronidase decreased the IL-1 inducing activity. Polymixin B, an inhibitor of endotoxin, did not exert any effect towards the action of hyaluronic acid. Hyaluronic acid also stimulated human polymorphonuclear leucocytes to produce IL-1 like activity. These results indicate that hyaluronic acid is an endogenous IL-1 inducer and may play important roles in the pathological and/or physiological changes of connective tissues.

Animals↗
PubMed1986

Hormonal control of collagenase inhibitor production in rabbit uterine cervical fibroblast-like cells.

Rabbit uterine cervical fibroblast-like cells maintained in fetal calf serum-free medium were found to biosynthesize and secrete a collagenase inhibitor into the culture medium. All the properties of this inhibitor were similar to those that have been described so far for the tissue inhibitor of metalloproteinases. Both progesterone and 17 beta-estradiol significantly increased the level of collagenase inhibitor without the proliferation of cells. These data suggest that both progesterone and estradiol regulate collagenolysis in the uterus bifunctionally by acceleration of the inhibitor production in addition to their known inhibitory actions towards collagenase biosynthesis.

Animals↗
PubMed1986

Active uptake of testosterone by androgen receptors of hepatocellular carcinoma in humans.

Hepatocellular carcinoma (HCC) is more prevalent in males than it is in females, which has often been explained by the fact that alcoholism and chronic hepatitis B virus infection are more prevalent among males. The current studies, using biochemical and autoradiographic methods, verified that HCC contains higher concentrations of androgen receptors than the surrounding liver parenchyma and that extrinsically given testosterone are actively taken up by such tumors. These results may suggest that HCC is an androgen-dependent tumor and that, therefore, this tumor is more prevalent in males than it is in females.

Autoradiography↗
PubMed1986

Estrogen receptors in hepatocellular carcinoma.

Estrogen receptors (ER) were assayed on hepatocellular carcinoma (HCC) and surrounding liver tissue in 30 adult patients. All specimens were obtained at the time of surgery. Cirrhosis of the liver was associated with 28 patients and chronic hepatitis in 2 patients. ERs were detected in 12 of 30 HCCs. The value ranged from 1.4 to 9.2 fmol/mg cytosol protein with the dissociation constant (Kd) value less than 1 nanomol. On the other hand, 13 of 28 cirrhotic livers had measurable amounts of the receptors that ranged from 1.5 to 4.1 fmol/mg cytosol protein. Two livers with chronic hepatitis did not have detectable amounts of ERs. The receptors were not detected in both the tumor and liver in ten patients. The ER titers in HCC did not have any correlation with serum levels of alpha-fetoprotein or carcinoembryonic antigen, hepatitis B virus profiles, and histologic types of the tumor. In the light of the current results, it would be of great interest whether hormone therapy can be used or not as a treatment of naturally occurring HCC in humans.

Aged↗
PubMed1986

Direct expression of urogastrone gene in Escherichia coli.

Human epidermal growth factor (urogastrone; UG) is a 53-amino acid polypeptide hormone. A 192-bp DNA fragment containing the coding sequence for methionyl UG (Met-UG) and the ribosome-binding site (RBS) was chemically synthesized and placed downstream from the promotor for the Escherichia coli outer-membrane lipoprotein gene (lpp) on a plasmid. E. coli cells harboring the plasmid directed the synthesis of Met-UG at 10(2)-10(3) molecules per cell. Next, the coding sequence for Met-UG was inserted in a runaway-replication plasmid and expressed under the control of the lpp promoter and the RBS derived from bacteriophage Mu cII gene. Upon heat induction, the cells harboring the recombinant plasmid synthesized 10(5) molecules of Met-UG per cell.

Amino Acid Sequence↗