Biomedical subjects

S Hirata

Publications and source records attributed to S Hirata.

At least 127 records · Page 7Linked to original sources

PubMed1994

Intravenous extended infusion of recombinant human soluble thrombomodulin prevented tissue factor-induced disseminated intravascular coagulation in rats.

This study demonstrated that intravenous infusion of recombinant human soluble thrombomodulin (rhs-TM) could inhibit disseminated intravascular coagulation (DIC) caused by 4 hr infusion of tissue factor (TF) in rats. Extended infusion of TF reduced fibrinogen and platelet counts and elevated serum FDP level. Pretreatment and coinfusion of rhs-TM could block changes of these DIC-parameters without prolongation of APTT. Heparin, which is a potent anti-DIC drug, could also inhibit these changes with extra prolongation of APTT and PT. Thus, these results suggest thrombomodulin prevent DIC less bleeding tendency than heparin.

Animals↗

PubMed1994

Cellular and matrix changes before and at the time of calcification in the growth plate studied in vitro: arrest of type X collagen synthesis and net loss of collagen when calcification is initiated.

To understand the growth, maturation, and regulation of growth plate chondrocytes, it is necessary to isolate the different chondrocytes into distinct subpopulations of maturational development. Five subpopulations (A-E) of bovine fetal growth plate chondrocytes were separated by discontinuous gradient centrifugation. Four subpopulations (B, C, D, and E, from low to high density) with good viability were cultured at high density in microwells for up to 30 days. They all established an extensive extracellular matrix composed of proteoglycan and collagen. The largest and last dense cells in subpopulation B were the first to synthesize (at days 5-6) type X collagen and to calcify this matrix. Matrix calcification (formation of hydroxyapatite in the presence of sodium beta-glycerophosphate) always followed the initiation of type X synthesis. All the other subpopulations synthesized type X collagen and calcified their extracellular matrix. Although these events occurred in the same order, they were delayed according to the order of increasing cell size. These observations indicate that these subpopulations represent different stages in cellular maturation that lead to expression of the hypertrophic phenotype. Once mineral formation was well established, there was an increase in the matrix content of the C-propeptide of type II collagen (which is known to bind to hydroxyapatite and accumulate in calcifying extracellular matrix). This was accompanied by a reduction in the total collagen content, which accompanied an abrupt reduction in type X collagen synthesis, whereas type II collagen synthesis was largely maintained. These reductions in collagen content and type II collagen synthesis were not observed in the absence of calcification (beta-glycerophosphate omitted from culture). This new culture system recreates many of the sequential cellular and extracellular changes exhibited in situ during the development of the physis and provides new information about cellular and extracellular matrix changes that occur before and at the time of calcification.

Absorptiometry, Photon↗

PubMed1994

Gene expression of progesterone receptor isoforms in the rat brain.

Progesterone receptors (PRs) are known to exist in two forms: a larger molecular, form B, and a smaller one, form A. Rat PR cDNA corresponding to the region around the translation-initiation site (ATGB) of the putative PR form B mRNA was cloned, together with cloning of steroid-binding domain of the PR forms A and B. An imperfect "estrogen responsive element," GGTCG*** TGACT, was located around ATGB of the rat PR cDNA. The distribution of PR mRNA-containing neurons was mapped in the female adult rat brain by in situ hybridization, which was largely in agreement with that of PR proteins. Differential intracerebral distribution of the mRNAs, measured by the quantitative RT-PCR Southern blotting assay, was found between the total (A+B) and form B mRNA levels, indicating possible distinct mechanisms responsible for regulation of the expression of the PR mRNAs. A region-specific and stage-related gene expression of form B seems predominantly to be "turned on" first around birth, followed by that of form A around Days 8-12. The postnatal developmental pattern of PR form B mRNA in the cerebral cortex resembled that of the PR proteins. Noninducibility of the cortical PR by estrogen might be ascribable to the predominance of form B mRNA, which was reported to have little or no estrogen inducibility. A missmatch existed between PR from A and its mRNA levels, suggesting some impairment of the synthesis of form A. Thyroid hormone may be a regulator of gene expression of the receptor in the developing cortex.

Amino Acid Sequence↗

PubMed1994

Simple method for determining proper length of artificial chordae in mitral valve repair.

A simple method for determining the length of artificial chordae in mitral reconstructive operations is described. A small tourniquet is used for fine adjustment of the length of polytetrafluoroethylene stitches before tying them during leaking test. We have used this technique in 10 consecutive patients with anterior mitral leaflet prolapse since August 1992. Intraoperative transesophageal echocardiography revealed no or only trace mitral regurgitation after valve repair in all cases. This method minimized the time of determining the proper length of artificial chordae and achieved good results.

Chordae Tendineae↗

PubMed1994

Effects of hypothyroidism on the gene expression of progesterone receptors in the neonatal rat brain.

The effects of neonatal hypothyroidism on the gene expression of progesterone receptors (PRs) in the 8-day-old female rat brain were examined. The levels of PR ('A'+'B')-, PR ('B')-, estrogen receptor (ER)- and beta-actin mRNAs in the cerebral cortex and hypothalamus-preoptic area of propylthiouracil-treated rats (PTU group) or untreated rats (control group) were analyzed using a quantitative reverse transcription-polymerase chain reaction-Southern blotting assay. When the levels of PR mRNAs were calibrated by respective levels of beta-actin mRNA, the levels of PR ('A'+'B')- and PR ('B') mRNAs in the cerebral cortex of the PTU group were markedly less than those in the control group with no significant changes in the levels of PR messages in the hypothalamus-preoptic area of both groups. No significant difference in the calibrated levels of ER mRNA between both groups was found in these tissues. These results on the PR-, and ER mRNAs were essentially similar to those on the levels of PR- and ER proteins previously reported suggesting that thyroid hormones affect the transcriptional machinery of PR in the developing brain, in a region-specific manner.

Animals↗

PubMed1994

Distribution and postnatal changes of aromatase mRNA in the female rat brain.

Distribution and postnatal changes of aromatase mRNA in the Wistar strain female rats brain were investigated to elucidate the mechanism of the region-specific and stage-related regulations of brain aromatase activity. Total RNAs extracted from the hypothalamus-preoptic area (HPOA), amygdala, cerebral cortex, cerebellum and anterior hypophysis were subjected to a quantitative reverse transcription-polymerase chain reaction-Southern blotting (RT-PCR-SB) assay. The levels of aromatase mRNA were as follows: amygdala > cerebral cortex not equal to HPOA >> cerebellum not equal to anterior hypophysis. These results roughly paralleled the distribution of the aromatase activity and the aromatase protein reported previously, with the exception of that of the cerebral cortex. The postnatal developmental patterns of aromatase mRNA in the HPOA and cerebral cortex were further studied. The levels of aromatase mRNA in the HPOA tended to be high around birth (day 0) and to decrease at days 4-8 followed by no remarkable change to an adult. The developmental pattern in the HPOA was essentially similar to that of aromatase activity. On the other hand, in the cerebral cortex where very low or no aromatase activity was reported throughout developmental stages, aromatase mRNA was low but detectable level around day 0, thereafter gradually increased to an adult level. From these results, it is inferred that synthesis of the aromatase protein by the level of the mRNA seems to mainly regulate the aromatase activity in a region-specific and stage-related fashion in most parts of the rat brain, except for the cerebral cortex where the posttranscriptional regulation may play an important role.

Animals↗

PubMed1994

Androgen receptor mRNA in the rat ovary and uterus.

The distribution of androgen receptor messenger RNA (ARmRNA) in the reproductive tissues of adult rats was examined by Northern blot analysis and in situ hybridization using ARcRNA probes corresponding to the androgen binding domain of the receptor. About 10-kilobase rat ARmRNA was observed in all tissues examined in the Northern blot analysis. The amount of ARmRNA in the ovary, uterus and testis was less than that in the prostate. In the in situ hybridization study, extensive labeling was observed in the theca cells of the ovary (proestrous) and the endometrium and endometrial glands of the uterus (proestrous). Moderate labeling was observed in the granulosa cells and stromal cells of the ovary and in the myometrium of the uterus. These results were largely in agreement with the distribution of AR previously reported by ligand binding studies. This present in situ hybridization study may provide a useful tool for the analysis of the regional regulation of AR synthesis in the rat female reproductive tissues.

Animals↗

PubMed1994

[Ritodrine induced pulmonary edema after caesarean section for a triplet pregnancy].

Selective beta-sympathomimetic drugs are frequently used for tocolysis. But, since these drugs exhibit some beta-1 activity as well, they may bring about pulmonary edema, myocardial ischemia, cardiac arrhythmia and others as side effects. A 29 year-old female with a triplet pregnancy had premature contraction at 26 weeks of gestation. High doses of IV ritodrine were given for tocolysis for 8 weeks until caesarean section. One hour after caesarean section at 35 weeks of gestation, she complained of dyspnea. Urinary output decreased and chest X-ray showed pulmonary edema. She was intubated and artificial ventilation with PEEP was performed in ICU. Echocardiogram showed left ventricular dilatation. ECG showed inverted T waves on all leads. We diagnosed her as suffering from acute heart failure, pulmonary edema and acute renal failure. Hemodialysis was performed for 6 hrs but PCWP was still 18 mmHg. So CVVH was added to hemodialysis. Five hrs after the start of CVVH, her symptoms gradually started to subside. Total fluid removal was 5.8 l over 16 hrs. Three days after admission she was extubated and five days later returned to her ward. We concluded that pulmonary edema, heart failure and renal failure were induced by the long-term high dose medication of ritodrine, resulting in volume overload and myocardial dysfunction.

Acute Disease↗

PubMed1994

[Advance of magnetic resonance spectroscopic imaging (MRSI) techniques].

Magnetic resonance spectroscopic imaging (MRSI) can provide density images of various metabolites in the human body, in vivo, by utilizing chemical shift. This technique has received attention as a new method for analyzing the diseased state, via metabolism. It increases the accuracy of diagnosis and provides hope for early diagnosis of brain disease. However, because a measurement time of more than ten minutes to one hour is required for imaging, it has been difficult to use MRSI techniques for clinical diagnosis. Improved techniques for high-speed imaging have recently been developed. This review describes the recent advances in this field.

Animals↗

PubMed1994

Painful bipartite patella in young athletes. The diagnostic value of skyline views taken in squatting position and the results of surgical excision.

Nine patients with painful bipartite patella associated with young athletes were evaluated clinically and radiologically at an average of 60 months (range, 21 to 145 months) after excision of accessory nucleus of the patella. All patients were male and between 14 and 21 years of age when they were operated on. The indications for excision of separated fragments of the patella included: failure of nonoperative treatment for more than 3 months; radiographic evidence of significant irregularities of the articular surface of the separated fragment of the patella; and symptoms severe and prolonged enough to warrant surgery. Skyline views taken with the patient in a squatting position with weight bearing showed a wider separation of the accessory fragment from the main patella than did the nonweight bearing skyline views. This appears to be an important and useful diagnostic feature in a painful bipartite patellae; the authors propose that this radiographic examination should be called a "squatting position test". Histologically, the interface between the accessory and main patella was fibrocartilaginous, and the adjacent bone tissue was clearly demarcated by a dense lamina, indicating that the initial lesion was probably a traction lesion. All patients returned to full sports activity at their previous highest level within 4 to 7 weeks. The excision of accessory bone appears to be a simple and reliable procedure for avoiding prolonged postoperative treatment, reducing the length of incapacitation, and minimizing the danger of permanent stiffness of the joint.

Adolescent↗

PubMed1994

[Treatment with arbekacin of surgical infections by resistant strains of Staphylococcus aureus. Arbekacin Study Group].

The frequency of infection by methicillin-resistant Staphylococcus aureus (MRSA) is high in Japan and control of such strains is urgently needed. Arbekacin (ABK), a semisynthetic aminoglycoside, has potent activity against S. aureus, including resistant strains, and against Gram-negative bacteria as well. For this reason, in surgical infections (which are often caused by more than one bacterium), this drug might be particularly effective. We calculated the MIC and the decrease in the MIC when cultures of 59 resistant strains of S. aureus isolated in our wards at Osaka City University Hospital, contained arbekacin in the medium. We also used the drug to treat 12 infections caused by resistant strains of S. aureus. The MICs of vancomycin had a single peak at 0.5 microgram/ml, and those for ABK had double peaks at 0.5 and 4.0 micrograms/ml. The effect of arbekacin in lowering the MIC of minocycline (MINO) was slight because of the low MIC of MINO. Effects on fosfomycin (FOM), ampicillin, clavulanic acid/ticarcillin, cefotiam, cefuzonam, flomoxef, and imipenem/cilastatin were strong; the peaks were lowered by 1/2(7)-1/2(11). When 1.0 micrograms/ml ABK was present in the medium, the efficacy of FOM was increased enough that, by prediction from the pharmacokinetics of FOM (blood level when given at the usual dose), all but one (2%) of the 47 resistant strains would be eradicated clinically. If 2.0 micrograms/ml ABK were in the medium, all strain would be eradicated, by our calculations. We treated 11 infections and one colonization by resistant strains of S. aureus with ABK and evaluated the response in these cases of infection. Four infections were treated with FOM as well. The clinical efficacy was good in four infections (three patients), fair in four, and poor in three, for an efficacy rate of 36%. All presumed causative bacteria were eradicated in two (18%) of the 11 infections and S. aureus strains were eradicated in three (27%) of the 11 infections. No symptoms of side effects were reported, but blood urea nitrogen and creatinine rose in a 72-year-old woman with duodenal perforation and peritonitis. The MIC levels of ABK were satisfactory, but clinical efficacy for staphylococcal infections caused by resistant strains was unsatisfactory.

Adult↗

PubMed1994

The role of adhesion molecules in synovial pannus formation in rheumatoid arthritis.

To elucidate the mechanism of cell binding to cartilage, using an immunoperoxidase technique with monoclonal antibodies against adhesion molecules, the pattern of distribution of these molecules at the rheumatoid pannus-cartilage junction has been investigated. Treatment with purified anti-human-monoclonal antibody CD54 anti-(ICAM-1) resulted in membrane staining of most of the large cells infiltrating the synovial tissue and bordering the pannus cartilage junction. When the specimen was treated with purified anti-human-monoclonal antibody CDw49d anti-(VLA-4), purified anti-human-monoclonal antibody CDw49e anti-(VLA-5), most of the cells in the cartilage pannus junction stained, but there were few staining cells against purified anti-human-monoclonal antibody CD11a anti-(LFA-1). There were some anti-ICAM-1 and anti-VLA-5 staining of the chondrocytes at or close to the junction. Human umbilical vein ECBBA1 (ELAM-1) staining was only observed on the endothelial cells of postcapillary venules in the synovial tissue. These results show that the specific adhesion molecules tested may play a role in rheumatoid pannus formation and that the increased expression of VLA-4, VLA-5, and ICAM-1 at the cartilage pannus junction may represent interaction with matrix protein. The VLA interaction appear to be involved in pannus attachment, whereas LFA-1 and ICAM-1 are involved in cell-cell interaction and may upregulate molecules such as VLA that are involved in attachment.

Adult↗

PubMed1994

[Molecular oncological study on DNA ploidy, Ki-ras point mutation, and p21 expression in colorectal cancer].

We studied DNA ploidy, point mutation of Ki-ras oncogene codon 12, and p21 expression using paraffin embedded materials from 42 cases of colorectal cancer. DNA ploidy was measured by the method of Hedley et al. flow cytometrically. Point mutation of Ki-ras oncogene was examined by the method of Bos et al. using a dot-blot screening procedure, and p21 expression was examined immunohistochemically. Incidence of aneuploidy, Ki-ras point mutation, and p21 expression was 71.4%, 26.2%, 40.5%, respectively. There was a very weak correlation between p21 expression and pathologic findings, but there was no correlation between pathologic findings and DNA ploidy, as well as Ki-ras point mutation. Patients who showed aneuploidy tended to have more point mutation of Ki-ras oncogene. There was no correlation between p21 expression and Ki-ras point mutation, as well as DNA ploidy. Although there was no correlation between Ki-ras point mutation and survival, a significant correlation between survival and DNA ploidy, as well as p21 expression was recognized. Patients who had tumors with diploidy or p21 expression tended to have better prognosis.

Adult↗

PubMed1993

Antithrombotic effect of recombinant human soluble thrombomodulin on endotoxin-induced disseminated intravascular coagulation in rats.

Thrombomodulin (TM) is an endothelial cell membrane glycoprotein which neutralizes thrombin procoagulant activity and accelerates the thrombin-catalyzed activation of protein C. We expressed recombinant human soluble TM (rhs-TM) in Chinese hamster ovary cells and compared the effects of rhs-TM and heparin on endotoxin-induced experimental disseminated intravascular coagulation (DIC) in rats. Experimental DIC was induced by a continuous intravenous infusion of endotoxin for four hours. rhs-TM or heparin was infused simultaneously with endotoxin. Treatment with rhs-TM significantly reversed the endotoxin-induced changes in significantly reversed the endotoxin-induced changes in following parameters: platelet count, fibrinogen level and fibrinogen and fibrin degradation products. Furthermore, glomerular fibrin deposits elevated by endotoxin treatment were reduced by the rhs-TM administration. Heparin showed the similar effects to rhs-TM. Activated partial thromboplastin time (APTT) in rats receiving rhs-TM were slightly longer than APTT in endotoxin-treated rats, but rats receiving heparin had much more prolonged APTT. From these results, we concluded that rhs-TM may be useful for the clinical treatment of DIC while having only minor adverse effects on APTT.

Animals↗

PubMed1993

Spontaneous hemopneumothorax with aberrant vessels found to be the source of bleeding: report of two cases.

We report herein our experience of two cases of spontaneous hemopneumothorax in which the source of bleeding was found to be aberrant vessels. Both patients were successfully treated by early thoracotomy. Case 1 was a 23-year-old female in whom chest X-ray revealed an air-fluid line and a bulla with a narrow restiform shadow connecting the pleural cupola. Angiography clearly visualized aberrant vessels branching from the costocervical trunk, distributed in and around the bulla in the apex of the lung, being the possible source of bleeding. These aberrant vessels were confirmed at surgery and resected. Case 2 was a 56-year-old male who underwent thoracotomy for persistent bleeding. At surgery, a continuously bleeding vessel from the pleural cupola was seen and ligated. The remnant of the vessel was located in the apex of the lung, and resected with the bulla. Thus, the rare entity of a congenital aberrant vessel lying concealed as a possible source of bleeding should be borne in mind.

Adult↗

PubMed1993

The ontogeny of gene expression of progestin receptors in the female rat brain.

The postnatal development of the progestin receptor (PR) system in the rat brain is a region-specific and stage-related process. In an attempt to analyze the molecular mechanism by which the dramatic change of gene expression of the PR occurs we have examined the level of PR mRNAs in the hypothalamus-preoptic area (HPOA) and cerebral cortex in development from fetal to postnatal stages of female rats. We used polymerase chain reaction to clone, from uterine cDNA, the cDNA corresponding to the steroid-binding domain of the PR forms 'A' and 'B' mRNA as well as the region around the translation-initiation site (ATG1) of the putative PR form 'B' mRNA. A quantitative reverse transcription-polymerase chain reaction assay was used to measure the level of mRNAs for PR forms 'A' and 'B' (total PR mRNAs) and PR form 'B'. There was a regional difference in the intracerebral distribution between the total and form 'B' mRNAs, indicating possible distinct mechanisms responsible for regulating the expression of the PR mRNAs. The PR mRNAs in the brain, already detectable 2 days before birth, increased at early neonatal stages. The total PR mRNAs in the cortex developed in a manner essentially similar to the PR protein at the early stages, but, surprisingly, unlike the receptor, the messages remained high at the later stages from day 18 to 8 weeks of life. On the other hand, the ontogeny of the cortical mRNA for form 'B', which predominantly existed in the region, resembled that of the cortical PR protein. In the HPOA the postnatal development of the form 'B' mRNAs was also roughly similar to the PR. These results suggest region-specific and stage-related gene expression of the PR isoform system in the developing brain: gene expression of form 'B' seems to be predominantly, first, "turned on" around birth, followed by form 'A' mRNA expression around days 8-12. Moreover, lowered levels of the cortical PR mRNAs in the propylthiouracil-induced hypothyroid rat, together with suppressed PR level, indicate a possible regulatory role of thyroid hormone on gene expression of the cortical receptor.

Amino Acid Sequence↗

PubMed1993

Detection and levels of androgen receptor messenger ribonucleic acid in the rat brain by means of reverse transcription-polymerase chain reaction.

In order to examine the existence and level of androgen receptor messenger ribonucleic acid (ARmRNA) in the rat brain, reverse transcription-polymerase chain reaction (RT-PCR)-Southern blot analysis was carried out. Total RNA extracted from each tissue was reverse transcribed, followed by PCR with two oligonucleotide primers specific for a part (458 bp) of the androgen binding domain of the rat ARcDNA. It was confirmed by direct nucleotide sequencing that the amplified fragment corresponded to part of the rat ARcDNA. To detect and quantify the amplified fragments, a Southern blot analysis was carried out. The levels of amplified fragments were calculated from the standard curve obtained from graded diluted adrenal total RNAs. In the present study, it was revealed that the RT-PCR-Southern blot analysis possessed a high-degree of sensitivity and allowed the quantitative estimation of mRNA. With this method, amplified fragments were obtained from all five brain regions examined. The results indicate that ARmRNA is widely distributed in the whole brain. Moreover, since the ARmRNA level roughly paralleled the AR protein level, it seems that the AR protein level in the brain may be primarily regulated by the ARmRNA level.

Amino Acid Sequence↗

PubMed1993

Adhesion molecules in the lymphoid cell distribution in rheumatoid synovial membrane.

The staining pattern of a group of adhesion molecules on the immunoreactive cells in the lining layer of lymphocytic infiltrates of the rheumatoid synovial membrane was studied, using monoclonal antibodies by immunoperoxidase staining method against LFA-1, VLA-4, VLA-5, ELAM-1, and ICAM-1. The cells of the lining layer were strongly ICAM-1+ and VLA-5+, suggesting (1) that ICAM-1 may function to facilitate the adhesion of ICAM-1 bearing type A cells to type B cells, and (2) that the lining cells may utilize VLA-5 for anchorage to fibronectin at the surface of the synovial membrane. In the lymphocyte-rich and transitional area, the endothelial cells of the postcapillary venules were both ELAM-1+ and ICAM-1+. ICAM-1 staining of mononuclear cells was weak in lymphoid aggregates, but strong in the transitional area, indicating a paucity of ICAM-1 bearing cells in the lymphocyte-rich areas. On the other hand, LFA-1 staining was very strong in the lymphoid aggregates and only moderate in transitional areas. This suggests that the large numbers of T4 cells in the lymphocyte rich areas are sufficiently activated to express substantial levels of LFA-1, and also that the LFA-1 molecule is an important receptor for emigration from postcapillary venules. In germinal center-like areas in lymphoid aggregates, most of the cells stained strongly for ICAM-1 and VLA-4, suggesting that the proliferation of B lymphocytes may be facilitated by LFA-1 and VLA-4 dependent T and B cell interaction. The VLA molecules stained in the transitional areas may provide appropriate adhesion and anchorage for the achievement of the variety of immune reactions which occur in these areas.

Antibodies, Monoclonal↗