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Biomedical subjects

R Yamamoto

Publications and source records attributed to R Yamamoto.

At least 145 records · Page 8Linked to original sources
PubMed1998

[Characteristics and outcome of stroke patients discharged from hospitals in an urban area of Japan].

The purpose of this study was to obtain the overall characteristics and outcome in stroke patients in an urban area of Japan, in order to develop some strategies for a community-based care system for improvement of the prognosis and activities of daily life in stroke patients. The present study, based on 4 hospitals in Yao city in Osaka, showed results as follows: 1) The number of stroke patients discharged from 4 hospitals during a recent one year period was 377 (216 men and 161 women). 2) The proportion of patients who died was 27%. Of the living patients, the proportions of patients who had motor paralysis or speech disturbance at discharge were 54% and 27%, respectively. 3) The proportion of patients who were to return to their home was 77% for all living patients. The proportion of patients who were not able to walk by themselves, or needed assistance in at least one of the activities of daily life was 31% and 28%, respectively, for all living patients who were to return to their home. This study showed that stroke registry from major hospitals in an urban area is useful for obtaining the overall characteristics of stroke patients in the area and promote community-wide programs in the prevention and home care of stroke.

Activities of Daily Living↗
PubMed1998

Endotoxemia after elective surgery for abdominal aortic aneurysm and the effect of early oral feeding.

BACKGROUND: Endotoxemia after major vascular surgery has been suggested to be caused by the passage of bacterial endotoxins through the gut. Early enteral feeding has been reported to prevent bacterial translocation. Therefore, we investigated the incidence of endotoxemia in 12 patients with normal liver function after elective surgery for abdominal aortic aneurysm. METHODS: Blood samples were taken from the brachial vein of each patient before surgery, 1 day after surgery, and 3 days after surgery. The endotoxin concentration was measured using a chromogenic endotoxin-specific assay. RESULTS: The endotoxin concentration was significantly higher one day after surgery (2.15+/-1.36 pg/ml) than that before surgery (1.27+/-1.00 pg/mL), (p<0.05). The mean endotoxin concentration in the patients after early oral feeding (0.74+/-0.74 pg/ml) was significantly lower than that in the patients who could not eat (1.58+/-0.48 pg/ml). CONCLUSIONS: A low concentration of systemic endotoxins can be observed after surgery for abdominal aortic aneurysm, and early oral feeding prevented this elevation.

Aged↗
PubMed1998

Examination of prognostic factors after resection of pulmonary metastasis of osteosarcoma by multivariate analysis.

Prognostic factors for the case of pulmonary metastasis of osteosarcoma was examined using the multivariate analysis. 1) The 3-year survival rate after operation of primary focus in 23 cases was 34.8% and the 5-year survival rate was 30.4%. The 3-year survival rate after the first operation of pulmonary metastasis was 30.4% and the 5-year survival rate was 12.2%. No deaths attributed to operation were found. 2) Gender, age, histological type, solitary or multiple pulmonary metastasis, laterality, number of pulmonary metastatic tumors, TDT and DFI were examined, and the laterality, number of pulmonary metastatic tumors and DFI were considered to be useful prognostic factors. DFI among them was most closely associated with postoperative survival days. 3) A significant difference in the number of excised nodules was found between the DFI less than 90 days group and the DFI not less than 90 days group, and the number in the former group was significantly larger. 4) It was suggested that postoperative observation and close examination for pulmonary metastasis at about 3 months intervals after of primary focus are important, and also, positive or negative pulmonary metastasis as the time of examination, particularly, the number metastatic nodules of less than 5 or not less than 5, are reflected in the prognosis. 5) Expected survival time after the first operation pulmonary metastasis appeared possible to estimate as 3.0 x DFI days.

Adolescent↗
PubMed1998

A case of pulmonary metastases of synovial sarcoma surviving for a long period after active surgery.

The patient was a 24-year-old woman. She underwent marginal excision of synovial sarcoma originating in the right femoral soft tissue at the age of 18, followed by local radiation therapy and chemotherapy. At the age of 20, abnormal shadow was indicated in bilateral lungs on plain roentgenography of the chest, and she underwent open-chest surgery for excision of bilateral pulmonary metastatic tumors. She was subjected to bilateral thoracotony repeatedly thereafter for a total of 5 times, and all of the metastatic foci detected in each operation were resected. Consequently, she has been surviving for a long period of about 7 years. The therapeutic outcome of tumor of bone soft tissue is greatly affected by its pulmonary metastasis. Although the therapeutic outcome has recently been improved by large dose chemotherapy and active excision of metastatic foci in the lung, survival time in the case of synovial sarcoma, giant cell sarcoma and Ewing's sarcoma is not very long yet. In the present study, we observed a patient who had lung metastasis of synovial sarcoma of which prognosis is generally considered poor has been surviving for a long time of 7 years owing to active excision of pulmonary metastatic foci. The relation of the present prognostic factors to those in the past were compared.

Adult↗
PubMed1998

Surgical repair of ventricular septal defect associated with absence of right superior vena cava and persistent left superior vena cava: a case report.

A nine-month-old boy, weighing 4840 g, with VSD associated with absent right superior vena cava and persistent left superior vena cava, successfully underwent surgical repair of VSD. This anomaly is rare and causes some surgical and electrophysiological problems. We discussed these problems and described the details of surgery in our case.

Heart Septal Defects, Ventricular↗
PubMed1997

Three vha genes encode proteolipids of Caenorhabditis elegans vacuolar-type ATPase. Gene structures and preferential expression in an H-shaped excretory cell and rectal cells.

The proteolipids of the vacuolar-type H+-ATPase (V-ATPase) are major components of the integral membrane sector. The vha-1 and vha-2 (vacuolar-type H+-ATPase) genes in Caenorhabditis elegans encode putative 16-kDa proteolipids and are tandemly localized on chromosome III. The vha-2 gene has three exons, whereas vha-1 has no introns. The deduced amino acid sequences of the two genes exhibit about 60% identity with the homologues from yeast, mouse, and cow. The mRNAs of both vha genes are trans-spliced to spliced leaders, suggesting that these genes constitute a polycistronic transcriptional unit. The vha-4 gene consists of four exons and is very similar to the yeast VMA16 gene that codes for the 23-kDa proteolipid. This is the first example of three distinct V-ATPase proteolipids being identified in higher eukaryotes. Northern blot and transgenic analyses show that the three vha genes may be highly expressed in the H-shaped excretory cell, rectum, and a pair of cells posterior to the anus. These results suggest that the V-ATPase activity may be important for exporting toxic compounds or metabolic wastes in this organism.

Amino Acid Sequence↗
PubMed1997

Ha-ras mutations in N-nitrosomorpholine-induced lesions and inhibition of hepatocarcinogenesis by antisense sequences in rat liver.

To evaluate the application of Ha-ras mRNA antisense oligonucleotide therapy for liver tumors, we examined the frequency and types of mutation in codon 61 of the Ha-ras oncogene in preneoplastic lesions and hepatocellular carcinomas induced by N-nitrosomorpholine (NNM) in rats. Thirty-seven percent of preneoplastic lesions and 50% of hepatocellular carcinomas contained mutations, mostly CAA-CTA and CAA-AAA transversions. We also investigated the effects on NNM-induced lesions of an antisense oligonucleotide directed against a point mutation (CAA-CTA) in codon 61 of Ha-ras mRNA. In this experiment, Sprague-Dawley rats were given free access to water containing NNM for 8 weeks and received twice-weekly i.p. injections of a mutated Ha-ras antisense oligonucleotide with a 5' phosphorothioate linkage or a sense oligonucleotide in oligonucleotide-liposome complexes. At week 16, rats that had received the mutated Ha-ras antisense oligonucleotides had significantly fewer and smaller preneoplastic lesions positive for glutathione-S-transferase, placental type, and had smaller hepatocellular carcinomas than rats that had received the sense oligonucleotide. Mean cellular fluorescence in the liver was found to increase with higher doses of mutated, fluorescein-isothiocyanate-labeled antisense or sense oligonucleotides. Moreover, mutated Ha-ras antisense oligonucleotide decreased the expression of mutated Ha-ras mRNA (CAA-CTA). Our findings indicate that mutated Ha-ras antisense oligonucleotide significantly inhibits hepatocarcinogenesis in rats and could be an effective therapy against liver tumors.

Animals↗
PubMed1997

Inhibition of transcription by the TAR RNA of HIV-1 in a nuclear extract of HeLa cells.

Regulation of transcription of human immunodeficiency virus type-1 (HIV-1) requires specific interaction of Tat protein with the trans-activation response region (TAR). Inhibition of replication of HIV-1 has previously been achieved with a TAR decoy, namely a short RNA oligonucleotide that corresponded to the sequence of the authentic TAR RNA. Since TAR RNA has the potential to interact with cellular factors, we examined the effect of TAR RNA on efficiency of transcription in nuclear of HeLa cell extracts. We performed an in vitro transcription assay in the presence of authentic TAR RNA using a template that was driven by the CMV (cytomegalovirus) early promoter in a HeLa nuclear extract and found, for the first time, that TAR RNA inhibited transcription by approximately 60-70% independently of the Tat-TAR interaction. Furthermore, we evaluated inhibition of transcription by variants of TAR RNA and found that the TAR RNA loop, bases surrounding the loop, the triple base bulge and the 'lower' stem region of TAR RNA were responsible for the inhibition of transcription. Taken together, earlier reports on proteins that bind to TAR RNA and the present results suggest that integrity of TAR RNA is important for efficient binding to cellular transcription factors. As judged from the significant inhibition observed in this study, the TAR decoy might sequester transcription factors and thus it might potentially be able to inhibit transcription of housekeeping genes that are unrelated to Tat function.

Base Sequence↗
PubMed1997

Hard work does not result in a decrease in meal quality: the case of a Japanese farming village.

Historically, when Japanese farmers engaged in hard labor, they were likely to increase their carbohydrate intake without increasing intake of other nutrients. After Japan's economic growth started in the 1960s, however, many kinds of food became available and affordable. We investigated whether farmers today have increased the nutrients in their diet in proper proportion to energy expenditures when they are engaged in farming work by comparing the quantity and quality of meals between farmers and other villagers within a small area of a farming village. The quantity of energy and other nutrients increased with farming work, but the amounts of each nutrient per unit of energy did not decrease with the increase in energy intake. The intake of each nutrient relative to the recommended dietary allowance for energy and each nutrient did not decrease with farming work either. It was concluded that the quality of meals of farmers does not decrease with the increasing energy intake for farming work when many kinds of food are available and affordable.

Adult↗
PubMed1997

Enhancement by monochloramine of the development of gastric cancers in rats: a possible mechanism of Helicobacter pylori-associated gastric carcinogenesis.

The effects of cytotoxic monochloramine on the development of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine were investigated in Wistar rats. After oral administration of drinking water containing the carcinogen and regular chow pellets for 25 weeks, rats received regular chow pellets or chow pellets containing 20% ammonium acetate, and normal tap water or water containing 30 mM sodium hypochlorite, with or without s.c. injection of taurine, until the end of the experiment in week 52. Treatment with both ammonium acetate and sodium hypochlorite significantly increased the incidence of gastric cancers in week 52, while the concomitant use of taurine with ammonium acetate and sodium hypochlorite significantly attenuated the enhanced gastric carcinogenesis. Spectrophotometric examinations revealed that taurine scavenged monochloramine. These findings suggest that Helicobacter pylori-associated gastric carcinogenesis may be mediated by monochloramine.

Animals↗
PubMed1997

Up-regulation of sodium channel subunit mRNAs and their cell surface expression by antiepileptic valproic acid: activation of calcium channel and catecholamine secretion in adrenal chromaffin cells.

Treatment of cultured bovine adrenal chromaffin cells with a therapeutic concentration (0.6 mM) of valproic acid (VPA) for > 24 h caused a time-dependent (t1/2 = 74 h) increase in [3H]saxitoxin binding up to 1.4-fold without altering the KD value; it was prevented by the simultaneous treatment with cycloheximide (an inhibitor of protein synthesis). VPA also raised Na+ channel alpha- and beta 1-subunit mRNA levels 1.4- and 1.7-fold at 24 h, and 1.6- and 1.8-fold at 72 h, respectively. Chronic (but not acute) exposure to VPA enhanced 22Na+ influx caused by various concentrations of veratridine 1.4-2.1-fold, even when assayed in the presence of Na+,K(+)-ATPase inhibitor, but did not change the EC50 value of veratridine. Ptychodiscus brevis toxin-3 allosterically potentiated veratridine-induced 22Na+ influx by approximately 2-fold in VPA-treated cells as in nontreated cells. Long-term treatment with VPA augmented veratridine-induced 45Ca2+ influx via voltage-dependent Ca2+ channels and catecholamine secretion, but had no effect on 45Ca2+ influx and catecholamine secretion caused by high K+ (a direct activation of voltage-dependent Ca2+ channels). Chronic treatment with VPA also enhanced nicotine-induced 22Na+ influx via the nicotinic receptor-ion channel complex 1.2-1.4-fold with little change in the EC50 value of nicotine, thereby increasing the nicotine-induced 45Ca2+ influx via voltage-dependent Ca2+ channels and catecholamine secretion. These results suggest that chronic treatment with VPA up-regulates cell surface expression of Na+ channels via the transcription/translation-dependent mechanisms, and probably of nicotinic receptors, thereby resulting in the enhancement of Ca2+ channel gating and catecholamine secretion.

Animals↗
PubMed1997

Brassinosteroids induce entry into the final stage of tracheary element differentiation in cultured Zinnia cells.

To elucidate the involvement of brassinosteroids in the progression of tracheary element differentiation in cultured Zinnia cells, we analyzed the effects of uniconazole, an inhibitor of brassinosteroid synthesis, and brassinolide, a biologically active brassinosteroid, on the accumulation of mRNAs for various genes that were expressed in different stages of differentiation. Uniconazole specifically suppressed the accumulation of transcripts for genes that were induced in the final stage of differentiation in association with secondary wall formation and cell death. This suppression was recovered with the addition of brassinolide. These results strongly suggest that endogenous brassinosteroids induce entry into the final stage of differentiation.

Brassinosteroids↗
PubMed1997

Lectin affinity electrophoresis in a yolk sac tumour in the vagina with yolk sac tumour-type glycoform of alpha fetoprotein.

AIMS: To investigate a potential diagnostic use of alpha fetoprotein (alpha FP) isoform analysis by lectin affinity electrophoresis to distinguish between endodermal sinus tumours arising in the vagina in infants from those at other sites. METHODS: alpha FP in the serum of a patient with a vaginal endodermal sinus tumour was analysed for its isoforms by lectin affinity electrophoresis. The isoforms were compared with that of cord serum, sera of hepatoid adenocarcinoma of the uterus, and endodermal sinus tumour of the ovary. RESULTS: The isoforms of alpha FP obtained by lectin affinity electrophoresis in the serum of the patient with vaginal endodermal sinus tumour differed from the isoforms of alpha FP in the cord serum of normal neonates, and sera of patients with hepatoid adenocarcinoma of the uterus or endodermal sinus tumour of the ovary. CONCLUSIONS: Endodermal sinus tumour arising in the vagina could be distinguished from that in the ovary by the lectin affinity electrophoresis, and a potential diagnostic use of alpha FP isoform analysis by the lectin affinity electrophoresis for the detection of the endodermal sinus tumour in infants was demonstrated.

Diagnosis, Differential↗
PubMed1997

Nitric oxide-dependent and -independent norepinephrine release in rat mesenteric arteries.

The role of nitric oxide (NO) in endogenous norepinephrine (NE) release in the perfused isolated rat mesenteric vasculature was examined. NE overflow elicited by electrical field stimulation (EFS) at various frequencies was significantly smaller at 24 than at 37 degrees C. The pressor response upon EFS at 8 and 10 Hz, however, was higher at 24 than at 37 degrees C. When production of NO was blocked by N omega-nitro-L-arginine (L-NNA), NE overflow upon EFS at each frequency of stimulation was diminished by 50% at 37 degrees C but remained unchanged at 24 degrees C, whereas the pressor response elicited by EFS became greater at 37 than at 24 degrees C. These effects of L-NNA were reversed by L-arginine, but not by its D-enantiomer. Sodium nitroprusside, an NO donor, increased EFS-elicited NE overflow at 24 degrees C but had no effect at 37 degrees C. These results demonstrate that NE release is NO dependent and NO independent. The NO-dependent mechanism is more sensitive to cooling than the NO-independent mechanism. The increase in EFS-elicited perfusion pressure at 24 degrees C may be due to reduction in synthesis of NO (a potent vasodilator), thus unmasking the effect of NE and other noncatecholamine vasoconstrictors.

Animals↗
PubMed1997

Menaquinone-4 accumulation in various tissues after an oral administration of phylloquinone in Wistar rats.

The distributions of phylloquinone (PK) and menaquinone-4 (MK-4) in various tissues were assessed after the oral administration of phylloquinone. Wistar rats were fed a vitamin-K-deficient diet for nine days, fasted for 24 h and then given phylloquinone orally at 4 mg/kg body weight. Rats were sacrificed 0, 6, 12 and 24 h after the administration, and an analysis was made of the vitamin K analogues in the plasma, liver, brain, testis, kidney and spleen. The phylloquinone concentration in plasma and the tissues reached a peak 6 h after the oral administration of phylloquinone. By contrast, the concentration of MK-4 peaked in the liver, plasma, kidney and spleen at 12 h, and in brain and testis at 24 h. This data suggests that the ingested phylloquinone was probably converted into MK-4 within the tissues themselves, rather than via hepatic metabolism. The evidence for this is that, after phylloquinone administration, (i) in each of the tissues, the MK-4 concentration increased much more slowly than that of phylloquinone, and (ii) the MK-4 concentration in the plasma and liver reached only much lower levels than those seen in other tissues.

Administration, Oral↗
PubMed1997

[The inhibitory effects of Arg-Gly-Asp-Ser on attachment of fibroblasts].

Trabeculectomy often fails because of scarring of the filtering bleb, which is caused by the proliferation of fibroblasts. In this study, we investigated the inhibitory effect of Arg-Gly-Asp-Ser (RGDS) oligopeptide, a cell binding domain of fibronection molecules, on the attachment of fibroblasts in vitro and on scarring of filtering bleb after trabeculectomy on rabbits' eyes. The following results were obtained. 1. RGDS inhibited the attachment of rabbit conjunctival fibroblasts significantly (p < 0.01) when it was added to the culture medium at final concentrations of 2 and 5 mg/ml. 2. The administration of 0.2 ml of RGDS solution (5 mg/ml) into the filtering bleb 3 days after surgery caused significant reductions of intra ocular pressure compared with the control maintained the bleb more than 13 days whereas the blebs of the control eyes disappeared within 6 days (p < 0.01). 3. No complications were caused on the eyeballs of the rabbits by the administration of RGDS.

Animals↗