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Biomedical subjects

Y Yamaguchi

Publications and source records attributed to Y Yamaguchi.

At least 757 records · Page 42Linked to original sources
PubMed1992

Comparative study of magnetic resonance and CT scan imaging in cases of severe head injury.

The distribution, frequency, and appearance of head injuries were evaluated with MRI and CT in a prospective study of 155 patients with acute (n = 124) and chronic (n = 31) head injuries. MRI was significantly more sensitive than CT in the detection of intraaxial injury at any stage. In severe cases, central structure lesions were detected in approximately 80% of patients. Severity on admission was compatible with MR findings. However it was difficult to decide on neurobehavioural prognosis from initial MRI findings only.

Adolescent↗
PubMed1992

Mitotic toxicity, sister chromatid exchange, and rec assay of pesticides.

Genotoxicity of 10 pesticides (chlornitrofen, chlomethoxyfen, molinate, thiobencarb, simazine, simetryn, diazinon, iprofenfos, piperofos and oxadiazone) was studied by mitotic toxicity, sister chromatid exchange, and rec assay. The pesticides are detected frequently at high levels in the Yodo River water in Osaka, Japan, which is used for drinking water by thirteen million people. Mitotic toxicity was evaluated by mitotic index (MI) and second mitosis index (SI), using a Chinese hamster cell line V79. SI is the rate of twice divided metaphases in chromosome preparation for sister chromatid exchange. All the pesticides decreased the two indices dose-dependently. MI50 and SI50, the concentrations of pesticides which lowered the indices to 50% of the solvent control, was determined. The MI50 and SI50 of each pesticide were very similar, and the pesticides did not hinder cell division specifically. None of the pesticides induced more sister chromatid exchanges than 1.5 times the solvent control. Chlomethoxyfen and simazine induced sister chromatid exchanges significantly in V79 cells, but the dose dependencies were poor. Simetryn had rec effect and was concluded to have DNA damaging activity.

Animals↗
PubMed1992

Factors influencing survival after endoscopic Nd:YAG laser surgery for unresectable advanced malignancies of the trachea.

The effects of endoscopic Nd:YAG laser surgery were studied in 36 patients with unresectable advanced primary and metastatic malignancies in the trachea with special reference to the factors influencing long-term survival. Overall effectiveness of YAG laser treatment was demonstrated in 34 of the 36 patients (94 per cent), while the overall 1, 3 and 5 year survival rates after the first laser treatment were 25 per cent, 13 per cent and 13 per cent, respectively. Neither histologic type nor the severity of clinical symptoms before laser treatment showed any significant influence on the survival curves, however, endoscopic findings of stenosis, the effect of laser treatment and irradiated longitudinal length were all significantly correlated with the survival curves. In other words, endoscopically protruding type tumors with a longitudinal length of irradiation of 3.0 cm or less, and good responses not only to laser treatment but also to other combined modalities are favorable factors for achieving long-term survival in patients with tracheobronchial malignancies undergoing endoscopic Nd:YAG laser treatment. Endoscopic Nd:YAG laser surgery is considered to be a promising part of the multi-modality treatment for unresectable advanced primary and metastatic malignancies of the trachea.

Aged↗
PubMed1992

Increased sensitivity for detection of human cytomegalovirus in urine by removal of inhibitors for the polymerase chain reaction.

The presence of inhibitors in urine interferes with the enzymatic reaction of the polymerase chain reaction (PCR) for detection of human cytomegalovirus (HCMV). To remove inhibitors, HCMV virions in urine were precipitated with polyethylene glycol, or DNA was extracted from urine by the use of glass powder and subjected to PCR followed by Southern blot hybridization with alkaline phosphatase-linked oligonucleotide probes. These simple, rapid methods increased significantly the sensitivity of PCR for detection of HCMV in urine.

Base Sequence↗
PubMed1992

Regional differences in insulin receptor function in Werner's syndrome.

Werner's syndrome is a genetic disease characterized by premature aging and is often associated with glucose intolerance due to insulin resistance. The clinical manifestations in this syndrome are preferentially expressed in the face and acral regions without apparent involvement of the trunk. We compared insulin receptor binding and amino acid uptake of fibroblasts derived from the forearm that had sclerodermoid features, and from the abdomen that was apparently normal in a patient with Werner's syndrome. In normal controls, specific insulin binding was not different in forearm and abdomen-derived fibroblasts (10.72 +/- 2.11%, 10.40 +/- 1.27%, respectively). In the patient, however, specific insulin binding was reduced in the fibroblasts derived from the forearm compared with those derived from the abdomen (3.55%, 8.16%, respectively). Scatchard analysis revealed that the reduction in insulin binding of the forearm fibroblasts from the patient was due to a reduction in receptor number with no change in receptor affinity. The dose-response curve for insulin of alpha-aminoisobutyric acid (AIB) uptake is shifted to the right in the fibroblasts derived from the acral area. The results show that in a patient with Werner's syndrome, regional differences occur in fibroblast insulin receptor binding and function. This suggests early phenotypic expression of the genetic abnormality of insulin receptor function in these patients.

Abdomen↗
PubMed1992

Changes in IL-6, IL-8, C-reactive protein and pancreatic secretory trypsin inhibitor after transcatheter arterial chemo-embolization therapy for hepato-cellular carcinoma.

In an attempt to investigate the interaction between the changes of cytokines and acute phase reactants after transcatheter arterial chemoembolization therapy (TACE), the levels of interleukin 6 (IL-6), interleukin 8 (IL-8), C-reactive protein (CRP) and pancreatic secretory trypsin inhibitor (PSTI) in the blood of patients with unresectable hepatocellular carcinoma (HCC) were measured. Before the therapy, serum IL-6 and plasma IL-8 levels were detectable in 77.8% and 28.5%, respectively, of patients with HCC. Levels of serum IL-6 and plasma IL-8 increased after TACE and reached a peak on day 3 in all patients (18/18) and in 87.5% of patients (12/14), respectively. Both blood levels of IL-6 and IL-8 reached a peak earlier than those of CRP and PSTI did after the therapy. When the maximal values of IL-6 were compared with those of CRP and PSTI, there were significant positive correlations (r = 0.63, P < 0.01 and r = 0.81, P < 0.01, respectively). Similarly, comparisons of the maximal values of IL-8 with those of CRP and PSTI gave a significant correlation (r = 0.68, P < 0.01 and r = 0.67, P < 0.05, respectively). However, no significant correlation was found between the elevation of IL-6 and IL-8.

Aclarubicin↗
PubMed1992

Penile reconstruction with de-epithelized superficial external pudendal artery flap.

Complete loss of skin, Buck's fascia and tunica albuginea of the corpus cavernosum occurred on both sides of the penile shaft after placement of a penile prosthesis for the treatment of Peyronie's disease. We describe this unusual complication and surgical reconstruction of the penis with a de-epithelized superficial external pudendal artery axial pattern flap (January 1988). A good result was obtained.

Humans↗
PubMed1992

Hypotensive and bradycardiac responses to thyrotropin-releasing hormone in a comatose patient.

A 46-year-old female motorcyclist, who suffered injuries to the brain stem in a traffic accident, showed hypotensive and bradycardiac responses to thyrotropin-releasing hormone (TRH) given to counter consciousness disturbance. The cardiodepressive responses to TRH were reduced with i.v. pretreatment with atropine sulfate, suggesting an involvement of the vagal nervous system in the development of the responses. Furthermore, this patient had complicated impairments in the sympathetic nervous system, which were revealed by the results of testing baroreceptor reflex sensitivity to pharmacological alterations in blood pressure. We thus speculate that the hypotensive and bradycardiac effects of TRH observed in this patient may result from derangements of the sympathetic nervous system caused by the injuries. This case report is believed to be a novel description of the cardiodepressive effects of TRH.

Blood Pressure↗
PubMed1992

Prolonged survival of rat hepatic allografts after total-body irradiation of the donors.

The effect of total-body irradiation of the donor on hepatic allograft survival was studied in the rat, with ACI(RT1a) as the donor and LEW(RT1(1)) as the recipient. LEW recipients of ACI liver transplants experienced severe acute rejection, with a mean survival of only 10.2 +/- 0.3 days. The doses of irradiation were 450, 750, and 1000 rads administered 24 hr prior to harvesting or subsequent transplantation. TBI with a dose of 750 rads significantly prolonged the survival of the hepatic allograft to 30.3 +/- 1.7 days, without concomitant immunosuppression. However, neither 450 rads nor 1000 rads of TBI resulted in successful suppression of graft rejection. TBI appeared to have a beneficial effect on hepatic allograft survival and to have no deleterious effect on isograft survival, suggesting a possible modulation of the immunogenicity of the donor organ. Although the cause of this beneficial effect is not clear, TBI with a dose of 750 rads 24 hr prior to organ harvest seems to be optimal to eliminate-antigen presenting cells in the donor organs.

Animals↗
PubMed1992

The time course of cell-mediated lympholysis in rat hepatic allograft recipients pretreated with a single donor-specific blood transfusion.

A single intravenous injection of 1 ml freshly heparinized donor blood seven days before transplantation significantly prolonged the survival of subsequent donor-specific hepatic allografts in the fully allogeneic ACI(RT1a-to-LEW(RT1l)) rat combination. The time course of cell-mediated lympholysis was studied in this animal model. The activity of CML in lymphocytes infiltrating into the hepatic allograft (CML-G) and in the spleen (CML-S) was determined by measuring % lysis of donor Con A blast cervical lymph node cells. Preoperative DST resulted in an increased activity of CML-S with a peak (31.6%, E/T = 150) on day 7. This increased CML-S activity after DST rapidly declined during the first days following hepatic transplantation. The activities of both CML-S and CML-G then increased after transplantation and reached peaks on days 15 (48%, E/T = 150) and 20 (2.57%, E/T = 75), respectively. These were much higher than the peak values of CML-S (11.2%, E/T = 150) on day 7 and CML-G (19.5%, E/T = 75) on day 6 in untreated controls and were followed by a subsequent gradual decrease in those activities to preoperative levels by day 113 posttransplant. Phenotypic analysis of lymphocytes infiltrating grafts in DST-treated hosts demonstrated that the CD4/CD8 ratio remained relatively constant (less than 1.0). While the ratio in control grafts increased and reached a peak (2.17) on day 9. Histological examination revealed that mononuclear cell infiltration of grafts reached a peak on day 9 in both DST-treated hosts and controls. This mononuclear cell accumulation gradually subsided in DST-enhanced grafts. The mitotic index of graft hepatocytes reached a peak on day 15 in DST-treated hosts and on day 7 in control. The evidence of prolonged survival of hepatic grafts in recipients pretreated with DST, despite the presence of cytotoxic T cells with increased CML activity in vitro, suggests that effector cytotoxic cell activity may not be necessary for rat liver allograft rejection and that there may be limitations in measuring host cytotoxic activity simply by CML assays.

Animals↗
PubMed1992

Negative regulation of catalase gene expression in hepatoma cells.

For an understanding of the molecular basis of the marked decrease in catalase activity of various tumor cells, expression of the catalase gene was studied in rat and human hepatoma cell lines and in rat liver, which was used as a control with high activity. RNA blot hybridization profiles and run-on assays indicated that the decrease in catalase activity was due to depression of catalase gene transcription. Chloramphenicol acetyltransferase (CAT) assays for the fragments with various lengths of the 5'-flanking region (up to -4.5 kb from the ATG codon) of the catalase gene revealed the presence of several cis-acting elements involved in the negative regulation of transcription. The most-upstream element with the strongest activity (-3504 to -3364 bp), when linked to the catalase promoter region (-126 bp) of the CAT construct and subjected to an in vitro transcription assay, did not yield transcripts in experiments with the hepatoma nuclear extract, whereas the unlinked template did yield transcripts. A gel shift competition assay using hepatoma nuclear extract showed the core sequence of the silencer element to be 5'-TGGGGGGAG-3'. A homology search found that the same core sequence was also present in 5'-flanking regions of the albumin gene and of some other liver enzyme genes, the expression of which has been reported to be down regulated in some hepatoma cells. Southwestern (DNA-protein) analysis demonstrated that an approximately 35-kDa nuclear protein bound to the silencer element was present in hepatoma cells but not in rat liver cells.

Animals↗
PubMed1992

Plasma cholesterol transport in anhepatic rats.

The plasma appearance of newly synthesized cholesterol in anhepatic laboratory diet-fed rats was 10% of the intact rat. In intact rats this cholesterol was mainly ester in lower density lipoproteins, but for anhepatic rats it was virtually only free in high density lipoprotein. Chylomicron cholesterol ester was removed much more slowly from anhepatic than control plasma and returned primarily as free in high density lipoproteins, with the control return 10 times the anhepatic return. Lower density lipoprotein cholesterol ester transfer to an extravascular pool in anhepatic rats was less than 10% of controls. The liver was responsible for 95% of the extravascular lower density lipoprotein ester pool and only 50% of the for high density lipoprotein ester. Despite decreased anhepatic lipoprotein catabolism, the mass of both plasma low and high density lipoproteins progressively decreased indicating an even greater decrease in influx. The anhepatic fractional catabolic rate of apo A1 was similar to controls, but that of apo E was considerably less. Despite the unchanged catabolism of apo A1 and the reduced catabolism of apo E, plasma apo A1 decreased less than apo E after hepatectomy. The anhepatic data confirm the pivotal role of the liver in maintaining plasma low and high density lipoprotein cholesterol concentrations. They suggest that, in addition to its anabolic and catabolic functions, the liver also acts as a reservoir buffering changes in plasma concentration.

Animals↗
PubMed1992

Synthesis and biological activities of optical isomers of 2-(4-chlorophenyl)-5,6-dihydro-(1)benzothiepino[5,4-c]pyridazin-3(2H)-o ne 7-oxide.

Two enantiomers of 2-(4-chlorophenyl)-5,6-dihydro-(1)benzothiepino[5,4- c]pyridazin-3(2H)-one 7-oxide ((+/-)-1: Y-23684) were synthesized in high yields by asymmetric oxidation of the synthetic precursor (2) using modified Sharpless reagent. Among the oxidants tested, cumene hydroperoxide (CHP) gave the highest optical and chemical yields, while tert-butyl, tert-amyl, and 1,1,3,3-tetramethylbutyl hydroperoxides did not show such high enantio-selectivities. The absolute configuration of (+)-1 enantiomer synthesized from 2, Ti(O-iso-Pr)4, (-)-diethyl tartarate, and CHP was determined to be S by X-ray crystallographic analysis. Both enantiomers, S-(+)-1 and R-(-)-1, and (+/-)-1 had approximately equivalent in vivo activities to antibicuculline test in mice and anticonflict test in rats, although S-( + )-1 showed about three times higher affinity to benzodiazepine receptor than R-(-)-1 in [3H]diazepam binding assay.

Animals↗
PubMed1992

Isolation and characterization of a novel membrane glycoprotein of 85,000 molecular weight from rat liver lysosomes.

We have purified and characterized a novel glycoprotein (r-lamp-3) with an apparent molecular weight (Mr) of 85,000 from membranes of triton-filled lysosomes (tritosomes) by the use of immunoaffinity chromatography on a column of monoclonal antibody-Sepharose 4B. r-lamp-3 accounted for approximately 4% of the total proteins in tritosomal membranes. The isoelectric point (pI) of r-lamp-3 was 4.5 and it was shifted to 6.5 after neuraminidase treatment with its molecular weight decreased by about 7000. Pulse-chase experiments in cultured rat hepatocytes using [35S]methionine showed that r-lamp-3 was initially synthesized as a 77,000 polypeptide and processed to a mature protein with an Mr of 85,000. Upon treatment with endo-beta-N-acetylglucosaminidase H (Endo H), the precursor and mature forms were converted to 55,000 and 73,000 polypeptides, respectively. From the Mr reduction of the precursor form, we estimated the presence of 10--12 N-linked oligosaccharides/r-lamp-3 polypeptide. The data on enzymatic deglycosylation suggested that the mature form of r-lamp-3 contained the same numbers of high mannose-type and complex-type N-linked oligosaccharide chains.

Animals↗
PubMed1992

Syntheses and anti-inflammatory activity of novel oximes and O-acyloximes.

Novel oximes were prepared from the corresponding aldehyde or ketone in the usual way, and a number of oxime esters, O-lauroyl, O-2-pyridinecarbonyl, O-nicotinoyl, and O-isonicotinoyl oximes were synthesized by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI)-4-dimethylaminopyridine (DMAP) method or a mixed anhydride method, in our search for potent anti-inflammatory compounds. The anti-inflammatory activity of these compounds was assessed by the carrageenan-induced paw edema assay in rats. The oximes (4, 5, and 13), O-lauroyloxime 1L, O-nicotinoyloximes (1N, 2N, 3N, and 4N), O-isonicotinoyloxime 1I, and O-2-pyridinecarbonyloxime 7P showed higher anti-inflammatory potency than aspirin, a prostaglandin cyclooxygenase inhibitor.

Animals↗