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Biomedical subjects

F Itoh

Publications and source records attributed to F Itoh.

At least 181 records · Page 10Linked to original sources
PubMed1989

Interaction of thrombin with heparin cofactor II and antithrombin III on prostacyclin production by cultured endothelial cells.

To investigate the physiologic function of heparin cofactor II (HCII), endothelial cells from human umbilical vein were incubated in vitro for 20 min with 0.5 NIH U/ml thrombin in the presence of HCII or antithrombin III (ATIII), and prostacyclin production determined by radioimmunoassay for 6-keto-prostaglandin F1 alpha, the stable metabolite of prostacyclin. Although ATIII at 20 mInh.U/ml slightly but significantly inhibited thrombin-induced prostacyclin production, neither unfractionated heparin (UFH) nor low molecular weight heparin (LMWH) at 1 U/ml accelerated the inhibitory effect of ATIII. HCII at 10 and 20 mInh.U/ml did not decrease thrombin stimulation of prostacyclin production in the presence or absence of UFH or LMWH. However, HCII caused a marked decrease in the thrombin-stimulated prostacyclin prostacyclin production in the presence of 2 mg/ml dermatan sulfate (DS). The significant inhibition by HCII occurred when the DS concentrations were 0.2 microgram/ml and higher. From these results we suggest that HCII may prevent a prostacyclin-induced inhibition of platelet aggregation for hemostasis when plasma is exposed to vascular smooth muscle cells or fibroblasts which synthesize a significant amount of DS.

Antithrombin III↗
PubMed1989

Identification and purification of the enhancer-binding factor of human immunodeficiency virus-1. Multiple proteins and binding to other enhancers.

The enhancer-binding factor of human immunodeficiency virus (HIV)-1 was purified from human B cells by sequence-specific duplex oligonucleotide affinity chromatography. Gel retardation assay and footprint analysis showed that the purified factor bound specifically to the HIV-1 enhancer sequence, and protected both direct repeats in the HIV-1 enhancer. The purified factor consisted of four main polypeptides of the molecular weight of 36,000-42,000. At least three of them had enhancer-binding activity after elution from sodium dodecyl sulfate-polyacrylamide gel and renaturation. UV cross-linking analysis also showed that at least two of the polypeptides in purified fraction had a binding activity specific for the HIV-1 enhancer. The purified factor activated transcription from the HIV-1 promoter in vitro, confirming that it was indeed a transcription factor for HIV-1. The purified factor also recognized sequences in the immunoglobulin kappa gene enhancer and the major histocompatibility complex class I gene enhancer with almost the same affinity as the HIV-1 enhancer. These results suggested the existence of multiple proteins which recognize the kappa B-related sequences. This regulatory factor should help in the study of the biochemical pathway underlying HIV production from latently infected cells.

Base Sequence↗
PubMed1989

Time dependent changes occurring in rat liver microsomes upon lipid peroxidation.

Steady-state fluorescence anisotropy of diphenylhexatriene and n-(9-anthroyloxy)stearic acids (n = 2,12) in rat liver microsomes showed a marked increase in the early stages of enzymatically or non-enzymatically induced lipid peroxidation. The changes in fluorescence anisotropy occurred in parallel with the formation of thiobarbituric acid-reactive substances (TBA-RS). Parallel to these changes, the fluorescence emitted from peroxidized microsomes increased markedly in the early stages of lipid peroxidation. In contrast to the changes in the fluorescence anisotropy and in the formation of TBA-RS, the fluorescence showed a continuing increase over the three hr period of lipid peroxidation. Glucose-6-phosphatase was inactivated in the early stages of lipid peroxidation, whereas NADH-cytochrome b5 reductase underwent a slow deactivation over three hr. The apparently slow deactivation of the peripheral protein may be explained by the formation of fluorescent substances.

Animals↗
PubMed1989

Protection of liver microsomal membranes from lipid peroxidation by garlic extract.

Garlic extract, the ethanol-soluble fraction of garlic, prevented formation of thiobarbituric-acid-reactive substances and fluorescent substances during lipid peroxidation of rat liver microsomes. Lipid peroxidation increased the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene labelled to the microsomes while this increase was prevented by the garlic extract. It thus seems probable that the garlic extract serves to maintain membrane fluidity. These effects were dependent on its concentration and particularly prominent on exceeding a certain concentration of garlic extract. These results suggest its possible role of protecting the membranes from lipid peroxidation.

Animals↗
PubMed1989

Presence of aberrant transcripts of ret proto-oncogene in a human papillary thyroid carcinoma cell line.

In a papillary thyroid carcinoma cell line, TPC-1, we found transcripts hybridizing to ret proto-oncogene (proto-ret) cDNA probes. The transcripts hybridized to the probes encoding the kinase domain but not to those of the transmembrane and extracellular domains of proto-ret. The sizes of the main transcripts in TPC-1 were aberrant, being 2.0, 2.5, 4.0 and 5.0 kb. In the neuroblastoma cell lines, the transcripts were 3.9, 4.5, 6.0 and 7.0 kb, which have been proved to be generated by alternative splicing and polyadenylation from the non-altered proto-ret oncogene. All of the four transcripts in TPC-1 are about 2 kb smaller than the corresponding ones in the neuroblastoma. From the length of the transcripts, it is suspected that the transcripts in TPC-1 are a rearranged form of proto-ret. This is the first report describing the aberrant transcripts of proto-ret in a human tumor.

Blotting, Northern↗
PubMed1989

Application of monoclonal antibody KH2 against lactosyl and neolactotetraosyl ceramide to immunohistochemical study of human cancers.

Monoclonal antibody KH2 (IgM) reactive with lactosyl ceramide and neolactotetraosyl ceramide was applied for the first time to the staining of human cancerous and noncancerous tissues which were fixed with formalin and embedded in paraffin. Digestive-tract cancers originating from stomach, colon, pancreas, gallbladder and bile duct were clearly stained. The staining intensity was especially strong in the apical portion and the intraluminal content of adenocarcinomas. In noncancerous tissues, it was of interest that gastric intestinal metaplasia and certain fetal tissues were stained. A part of the tubules of the kidney, pancreatic ductal cells, lung alveolar epithelial cells and polymorphonuclear leukocytes were stained in normal adult tissues in our study. Enhancement of the intensity of immunostaining by neuraminidase treatment indicated that most of the antigenic determinants should be sialylated and the antigenicity exposed after neuraminidase treatment in several kinds of cancerous and noncancerous tissues. These data suggest that the monoclonal antibody KH2 may be useful in the immunohistologic diagnosis of formalin-fixed human cancerous tissues.

Antibodies, Monoclonal↗
PubMed1989

Human ret proto-oncogene mapped to chromosome 10q11.2.

Using cosmid clones derived from human ret protooncogene as probes, we determined its chromosome localization by fluorescence in situ hybridization. Two overlapping clones, cret-1 and -2, which were cloned using the most 5' part of human ret proto-oncogene cDNA, hybridized to chromosome 10q11.2. Sixty-three and 52% of the grains obtained by cret-1 and -2, respectively, were localized to the same site. No other specific hybridization site was observed. From these data, we assigned the site of ret proto-oncogene to chromosome 10q11.2, where the possible locus responsible for multiple endocrine neoplasia type 2A (MEN2A) was mapped by linkage analysis using interstitial retinol binding protein cDNA and D10S5. These findings suggest that ret proto-oncogene might be a suitable probe for approaching the MEN2A locus.

Chromosome Mapping↗
PubMed1988

Fluorescence emitted from microsomal membranes by lipid peroxidation.

The fluorescence emitted from rat liver microsomal membranes which had undergone enzymatic and nonenzymatic lipid peroxidation was detected directly. This fluorescence produced in peroxidized membranes increased progressively with peroxidation reaction time, and the fluorescent substances produced were retained in the membranes without being released into the aqueous phase. Extracts of the peroxidized membranes with organic solvents (chloroform/methanol) emitted fluorescence which was also dependent on the peroxidation reaction time. The generation profiles of fluorescence emitted from both the peroxidized membranes and their extracted membrane lipids differed essentially from that of thiobarbituric acid-reactive substances which reached a plateau at a relatively early stage of peroxidation reaction. These results indicate that lipid peroxidation induces stepwise chemical and physical changes in membranes and that the fluorescence from peroxidized membranes will be useful in studying such changes occurring in biological membranes.

Animals↗
PubMed1985

Benign hemangioendothelioma of the pancreas with obstructive jaundice.

A 3-year-old boy with benign hemangioendothelioma of the pancreas is reported. He showed the presenting sign of obstructive jaundice. The boy was treated with temporary choledochojejunal bypass without additional treatment. In a 16-month follow-up the child has been well and asymptomatic. Laboratory data showed no abnormality. Biopsied specimen of pancreatic head showed hemangiomatous pattern histologically. Immunohistochemical studies of the biopsy revealed positive reaction to factor VIII-related antigen (FVIII-RAG), and endothelial cell marker, supporting an endothelial origin. Hemangioendothelioma has a favorable prognosis and spontaneous regression can be expected. So the first treatment of the tumor should be conservative.

Child, Preschool↗
PubMed1983

A rheoencephalographic study of the cerebral blood flow in patients with the vibration disease.

One hundred and seven patients with the vibration disease and 26 controls were examined, using rheoencephalograms of the frontal, occipital and basilar areas to ascertain the state of the cerebral blood flow. Pulse waves were obtained at rest and after nitroglycerin administration. Indices of upstroke time (UT), upstroke rate (UR), dicrotic index (DI) and minute volume (MV) were calculated by analyzing the data. Cerebral blood vessels of the patients were tonic and functionally contracted, and it was suggested that organic changes were induced in the blood vessels of the basilar area especially in stage IV patients who were the most severe.

Adult↗
PubMed1982

Urinary retention caused by impaction of enlarged uterus.

2 cases of urinary retention were reported which was caused by retroverted gravid uterus and a large fibroid uterus, respectively. A chain cystourethrography and an endoscopic examination were the most informative to disclose the pathogenesis of urinary retention. Urodynamically, bladder compliance was normal without any pathological contraction. Urethral function was characterized by a shortened functional profile length.

Adult↗
PubMed1981

The effects of variable noise level on man with peak levels below 75 dB(A).

To estimate the effect of variable traffic noise levels by field study, six healthy students were exposed to such noise for 8 h in a building beside a highway. TTS increases and blood pressure changes were observed. A summary of the results is as follows: 1. Noise level slightly exceeded 70 dB(A) (Equivalent Sound Level, Leq). The ninety percent range of the changing noise level was within L50 + 10 dB(A). 2. The Temporary Threshold Shift (TTS) induced by variable noise increased slightly in this field experiment. In particular, regression of the logarithm of exposure time (min) to TTS at the "S" ward office, was statistically significant. Some subjects showed a rise of blood pressure due to noise exposure. 4. Even though noise level is below 75 dB(A), 8 h noise exposure induces TTS increase and elevation of blood pressure.

Auditory Fatigue↗
PubMed1981

Physiological responses induced by 555-min exposure to intermittent noise.

Normal medical college students were exposed to noise for 555 min, while the Temporary Threshold Shift (TTS) and changes in the circulatory system were measured. The exposure noise employed was the so-called pink noise of a trapezoidal form. There were two time patterns, A(I) with 1 s of rise-decay time and 1 s of peak level, and A(II) with 500 ms of rise-decay time and 3.5 s of peak level. Thirteen exposure conditions were examined. The noise exposure time of all experiments was 555 min. The following results were obtained. 1. TTS Growth. Significant TTs increases were obtained following exposure to intermittent noise of 85 dB(A), intermittent noise of 80 dB(A), and steady state noise of various intensities. The TTS growth observed with steady state noise at 80 dB(A) was significantly greater than that of intermittent noise exposure at 85 dB(A). Moreover, TTS growth observed with steady noise at 82 dB(A) was significantly greater than that with intermittent noise exposure of 85 dB(A). However, the levels of TTS growth observed with steady state noise of 75 dB(A) and steady state noise at 77 dB(A) were almost equal to those of 6 s trapezoidal noise at 80 dB(A) (the "on fraction" being 33%), and 8 s trapezoidal noise at 80 dB(d) (the "on fraction' being 50%). In the above-mentioned experiments, significant increases of TTS growth were observed with various cycle times of trapezoidal noise with peak levels of 85 dB(A) and 80 dB(A), and with four exposure noise conditions of steady state. Under exposure conditions of 75 dB(A), trapezoidal noise with a 6 s cycle time (the "on fraction" being 33%) did not show a significant increase in TTS growth. 2. Changes in the Circulatory System. There were no significant differences in systolic and diastolic pressure or pulse rate among the three exposure conditions. The findings on ECG were as follows. Under intermittent noise exposure, decrease in the height of the T wave was observed in all examinees with a depression of the ST segments also being observed in two cases. On exposure to steady state noise, however, slight decrease in the height of the T wave was induced in only two cases, and under control conditions in only one case.

Adult↗
PubMed1980

Sex difference of mercuric chloride-induced renal tubular necrosis in rats--from the aspect of sex differences in renal mercury concentration and sulfhydryl levels--.

When doses of 0.3 to 2 mg/kg of mercuric chloride were intravenously administered to rats of the JCL-SD strain, acute renal tubular necrosis was produced in the straight portion of the proximal tubules with a pronounced sex difference, the male being more susceptible. Necrosis was inhibited by castration of male rats and promoted by testosterone pretreatment. When 0.15 mg of mercury per rat was injected to adult rats, females showed higher levels of mercury in the whole kidney, outer cortex and inner cortex. Castration of male rats caused elevated renal levels of mercury and pretreatment with testosterone of females lowered the levels. Renal levels of sulfhydryl groups were higher than male rats and castrated male rats showed elevated renal levels. The sex difference in the levels of sulfhydryl groups seems to be one factor which causes different susceptibility to mercury between males and females.

Acute Kidney Injury↗