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Biomedical subjects

K Shibata

Publications and source records attributed to K Shibata.

At least 379 records · Page 21Linked to original sources
PubMed1994

Epidural anesthesia modifies the cardiovascular response to marked hypercapnia in dogs.

BACKGROUND: There is little information on the cardiovascular response to marked hypercapnia during epidural anesthesia (EA). Our objective was to assess the potential modifying effects of various levels of EA on this response. METHODS: We randomly assigned 48 mongrel dogs anesthetized with halothane (0.5%) to one of four groups: control (n = 12), receiving general anesthesia alone; lumbar (n = 12), also receiving lumbar EA; thoracic (n = 12), also receiving thoracic EA; and thoracolumbar (n = 12), also receiving thoracolumbar EA. During marked hypercapnia (mean arterial CO2 tension > 90 mmHg for 15 min), we measured hemodynamic parameters and plasma catecholamine concentrations in each group. RESULTS: In the control condition, marked hypercapnia increased cardiac output, reduced systemic vascular resistance, modestly increased mean arterial blood pressure. Lumbar EA abolished the increase in cardiac output, and thoracic and thoracolumbar EA caused CO2 to depress the cardiac output and the mean arterial blood pressure during marked hypercapnia. The physiologic increase in circulating catecholamines during marked hypercapnia was abolished only in the thoracolumbar EA group. CONCLUSIONS: We conclude that sympathetic blockade by EA modifies the cardiovascular response to marked hypercapnia in dogs. Although modest hypoventilation is often effective in treating hypotension during general anesthesia, the current results suggest that hypoventilation may be detrimental during the combination of EA and general anesthesia.

Anesthesia, Epidural↗
PubMed1994

Purification and characterization of an acid phosphatase from Mycoplasma fermentans.

An acid phosphatase associated with the cell membranes of Mycoplasma fermentans was released from the membranes with Triton X-100, then purified by ion-exchange chromatography on DEAE-Sephacel and CM-Sepharose, followed by affinity chromatography on Con A-Sepharose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme revealed a single band with a molecular mass of 31.2 kilodaltons. The enzyme activity toward p-nitrophenyl phosphate was enhanced remarkably by Cu2+, Co2+ and Mg2+, but the activity was not inhibited by EDTA. The enzyme dephosphorylated O-phospho-L-tyrosine as well as p-nitrophenyl phosphate, but not O-phospho-L-threonine, O-phospho-L-serine, glucose-1-phosphate, phosphoryl choline and adenosine triphosphate. The level of the O-phospho-L-tyrosine phosphatase activity was the highest in Mycoplasma faucium and the second highest in Mycoplasma fermentans of all tested human mycoplasmas.

Acid Phosphatase↗
PubMed1994

Purification and characterization of membrane protein (90 kDa) from Mycoplasma salivarium, which binds immunoglobulin (Ig) G Fc fragment.

A 90 kDa protein of Mycoplasma salivarium was released from cell membranes of the organism with Triton X-100 and purified by ion-exchange chromatography and chromatofocusing. The protein was eluted at pH 5.5 by chromatofocusing. The protein was shown to react with the Fc fragments of IgG from human and nine different animal species and did not distinguish between IgG from different species, while protein A, tested for comparative purposes, displayed a strong specificity for human and swine IgG. Furthermore, the protein reacted with antigen specific goat IgG (specific for gamma chains of human IgG), sheep red blood cells (SRBC) sensitized with rabbit antiserum to SRBC, that is, the Fc part of rabbit IgG, and concanavalin A as well. These findings may suggest that the protein is a lectin which binds the carbohydrate moiety of the Fc part of IgG.

Animals↗
PubMed1994

Identification of causative chemicals of allergic contact dermatitis using a combination of patch testing in patients and chemical analysis. Application to cases from rubber gloves.

5 cases of allergic contact dermatitis from rubber gloves were investigated by our recommended procedures using a combination of patch testing in patients and chemical analysis of causative rubber products by gas chromatography (GC) and high-performance liquid chromatography (HPLC). We previously confirmed that zinc ethylphenyldithiocarbamate (ZEPC), a dithiocarbamae-type accelerator (DTC), was causative in a case of allergic contact dermatitis from rubber work gloves. Subsequently, we have clarified that DTCs such as zinc dimethyldithiocarbamate (ZDMC), zinc diethyldithiocarbamate (ZDEC) and zinc dibutyldithiocarbamate (ZDBC) and amines such as dimethylamine (DMA), diethylamine (DEA) and piperidine (PIP) were also causative in cases from surgical rubber gloves. Thus, our investigative studies revealed that, although thiurams have been taken much more notice of as allergenic compounds than their corresponding DTCs and amines, not only DTCs such as ZDMC, ZDEC, ZDBC and ZEPC, but also amines such as DMA, DEA and PIP were noteworthy causative candidates of allergic contact dermatitis from rubber gloves.

Adult↗
PubMed1994

Microphthalmia-associated transcription factor as a regulator for melanocyte-specific transcription of the human tyrosinase gene.

Tyrosinase is a rate-limiting enzyme in melanin biosynthesis and is specifically expressed in differentiated melanocytes. We have identified the enhancer element in the 5'-flanking region of the human tyrosinase gene that is responsible for its pigment cell-specific transcription and have termed it tyrosinase distal element (TDE) (positions -1861 to -1842). Transient expression assays showed that TDE confers efficient expression of a firefly luciferase reporter gene linked to the tyrosinase gene promoter in MeWo pigmented melanoma cells but not in HeLa cells, which do not express tyrosinase. TDE was specifically bound by nuclear proteins of MeWo and HeLa cells, the binding properties of which were indistinguishable in gel mobility shift assays. TDE contains the CATGTG motif in its center, and mutation analysis indicates that the CA dinucleotides of this motif are crucial for protein binding and pigment cell-specific enhancer function. The CATGTG motif is consistent with the consensus sequence recognized by a large family of transcription factors with a basic helix-loop-helix structure, which prompted us to examine the possible involvement of a ubiquitous transcription factor, USF, and a novel factor, microphthalmia-associated transcription factor (MITF), recently cloned as the human homolog of the mouse microphthalmia (mi) gene product. The mi phenotype is associated with a mutant mi locus and characterized by small eyes and loss of melanin pigments. Both USF and MITF are predicted to contain a basic helix-loop-helix structure and a leucine zipper structure. We provide evidence that USF binds to TDE, whereas we were unable to detect the DNA-binding activity of MITF. Transient coexpression assays showed that MITF specifically transactivates the promoter activity of the tyrosinase gene through the CATGTG motif of TDE but not the promoter of the ubiquitously expressed heme oxygenase gene, while USF is able to activate both promoters. These results indicate that MITF is a cell-type-specific factor that is capable of activating transcription of the tyrosinase gene.

Base Sequence↗
PubMed1994

Slow hemodialysis performed during the day in managing renal failure in critically ill patients.

Slow hemodialysis (HD) was performed for 10 h during the day in 11 critically ill patients with renal failure. The dialysis method was a modification of the pump-driven continuous venovenous HD. A nonsterile bicarbonate-containing hemodialysate was passed into the EVAL membrane dialyzer at a flow rate of 30 ml/min. No patient developed further hemodynamic instability during the treatment. The serum urea level was maintained below 20 mmol/l within 4 days of initiating the treatment. It allowed the patients to rest without interruption at night. This method was safely conducted by general nursing staff under the supervision of nephrologists on duty during the day. This schedule offers an approach to renal replacement therapy for hemodynamically unstable patients without any potential problem in the extracorporeal circulation at night.

Acute Kidney Injury↗
PubMed1994

Essential thrombocythemia terminating in acute leukemia with minimal myeloid differentiation--a brief review of recent literature.

Essential thrombocythemia (ET), one of the chronic myeloproliferative disorders, is a clonal disorder of multipotent stem cells. Although most patients with ET have a prolonged benign course, a minority of patients may develop a blastic crisis similar to chronic myelogenous leukemia (CML). A case of ET terminating in blastic crisis 8 years after the initial diagnosis is presented. The blast cells were cytochemically and immunophenotypically consistent with the acute myelogenous leukemia with minimal myeloid differentiation subtype of the FAB classification. From the review of the literature on blastic transformation of ET, acute leukemia with an M4 or M7 phenotype occurred more frequently. In addition, three valuable factors to predict the leukemic transformation of ET appear to be karyotypic abnormalities, such as involvement of chromosome 21, previous therapies with a mutagenic potential, and the capability of bone marrow cells to form in vitro spontaneous colonies as in CML.

Acute Disease↗
PubMed1994

Possible functional groups responsible for inhibition of in vivo angiogenesis by herbimycin A.

Six herbimycin A (HBM) derivatives were examined for their anti-angiogenic effects in a bioassay system involving chorioallantoic membranes (CAMs) of growing chick embryos on the basis of our previous observation that HBM is a potent angiogenesis inhibitor. 17-Cyclopropylamino-HBM dose-dependently inhibited embryonic angiogenesis. The ID50 value was 0.1 microgram (160 pmol) per egg and thereby lower than that of the parent compound HBM (ID50 = 0.15 micrograms (260 pmol) per egg). In contrast, 19-dimethylamino-, N-acetyl-, 2,3,4,5-tetrahydro- and 7-decarbamoyl-HBM at doses of 0.01-10 micrograms/egg failed to affect angiogenesis in CAMs. These results strongly suggest as follows: (1) C-19 position, amino group between positions C-1 and C-20 and carbamoyl group in C-7 are essential for the anti-angiogenic action of HBM; (2) HBM needs certain fixed conformation for expression of angiogenesis inhibition; (3) it is expected that the modification of C-17 with a suitable functional group results in increased anti-angiogenic potency of HBM--that is, a more potent angiogenesis inhibitor than the parent compound would be developed.

Allantois↗
PubMed1994

Regulation by protein kinase C of platelet-activating factor- and thapsigargin-induced calcium entry in rabbit neutrophils.

12-O-Tetradecanoylphorbol-13-acetate (TPA) time-dependently inhibited the platelet-activating factor (PAF)-induced rise in cytosolic free calcium concentration ([Ca2+]i) in rabbit neutrophils, whereas staurosporine significantly enhanced it. Inositol 1,4,5-trisphosphate (IP3) induced Ca2+ release in digitonin-permeabilized cells but not in PAF-pretreated permeabilized cells. IP3-induced Ca2+ release was not affected by protein kinase C activators or inhibitors. In the cells pretreated with PAF and thapsigargin in Ca(2+)-deficient medium, stimulated Ca2+ entry was evoked by the subsequent addition of CaCl2. TPA inhibited the Ca2+ entry induced by PAF and thapsigargin in a staurosporine-reversible manner but not thapsigargin-induced [Ca2+]i elevation. These results suggest that protein kinase C negatively regulates PAF- and thapsigargin-induced rise in [Ca2+]i possibly by inhibiting Ca2+ store depletion-induced Ca2+ entry.

Alkaloids↗
PubMed1994

[A case report of interstitial pneumonia caused by granulocyte colony-stimulating factor].

Several clinical trials have demonstrated that granulocyte colony-stimulating factor (G-CSF) accelerates the recovery of neutropenia in chemotherapy-induced bone marrow suppression. In this report, we describe a 46-year-old female with glioblastoma multiforme who developed interstitial pneumonia due to administration of G-CSF during the phase of immunochemoradiotherapy-induced neutropenia. Thirty-three days after starting immunochemoradiotherapy (ACNU, VCR, IFN -beta, radiation), she developed neutropenia (1,000/microliters). Administration of G-CSF at doses of 125-250 micrograms/day led to an increase of peripheral neutrophil counts. Eleven days later, the patient developed sudden severe respiratory failure and cyanosis with worsening of lung shadows. Blood gas levels on room air were PaO2 49.3mmHg, PaCO2 28.0mmHg, and pH 7.46. At this time, her neutrophil count had risen to 26,080/microliters. LDH and alpha - HBD had also increased to 1,439 IU/l and 1,117IU/l respectively. Chest radiograph and CT scan demonstrated interstitial pneumonia. After treatment with methyl prednisolone, her respiratory symptoms were gradually resolved. A number of side-effects have been reported with granulocyte-macrophage colony-stimulating factor (GM-CSF). These include fluid retention with pericardial and pleural effusion, fever, bone pain, fatigue, and rash. This report also suggests that G-CSF might be a cause of interstitial pneumonia during the phase of immunochemoradiotherapy-induced neutropenia.

Brain Neoplasms↗
PubMed1994

[A case of occipital lobe epilepsy following cerebral infarction].

We report a rare case of occipital lobe epilepsy following cerebral infarction in bilateral occipital lobes. The patient is a seventeen-year-old female, who had cerebral infarction in bilateral occipital regions a few days after an open-heart surgery at 15 years of age. Thereafter she sometimes complained of visual field defects and ictal amaurosis. Seventeen months later, she developed a tonic seizure with ictal amaurosis, visual field defects and head deviation. On admission, results of the neurological examinations were all normal with the exception of peripheral visual field defects. Scalp electroencephalographic (EEG) findings showed paroxysmal discharges that were more prominent in the frontal to parietal leads than in the occipital leads. Sometimes the laterality of paroxysmal discharges changed. Her visual defects were diagnosed as psychogenic activity by the ophthalmological visual fields test. Simultaneous recordings of pattern reversal visual evoked potential (VEP) and electroretinograms (ERG) showed normal in 15 minute checks, but prolongation of bilateral P100 latency in 30 minute checks. These findings suggested that peripheral visual fields were disturbed. In this case, EEG findings and the initial symptoms of amaurosis and visual fields defect suggested occipital epilepsy following cerebral infarction in bilateral occipital lobes. We wish to emphasize that simultaneous VEP and ERG recording is a useful diagnostic tool for estimating visual functions.

Adolescent↗
PubMed1994

Effect of 12-hydroxyeicosatetraenoic acid on cytosolic calcium in human neutrophils.

12-Hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) has been reported to be a chemoattractant for human neutrophils. To assess its cellular mechanism, we focused on the effect of 12-HETE on cytosolic Ca2+ ([Ca2+]i) and characterized the effect of 12-HETE on [Ca2+]i in human neutrophils. 12(S)- and 12(R)-HETE increased [Ca2+]i in the presence and absence of extracellular Ca2+ in a concentration-related fashion. The elevation of [Ca2+]i by 12(R)-HETE was completely abolished by pertussis toxin treatment. U-73122, a selective phospholipase C inhibitor, depressed the 12(S)- and 12(R)-HETE-induced rise in [Ca2+]i in the presence and absence of extracellular Ca2+. 12(R)-HETE resulted in the rapid production of inositol 1,4,5-trisphosphate (IP3). Furthermore, 12(R)-HETE elicited slight depolarization of neutrophils as assessed using the fluorescent dye bis-oxonol. These results provide evidence demonstrating the signal transduction pathway in human neutrophils after stimulation with 12-HETE and suggest that 12-HETE causes a rapid rise of [Ca2+]i by mobilizing Ca2+ from an IP3-sensitive intracellular Ca2+ pool in human neutrophils.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1994

Pharmacokinetic profiles of intravenous imipenem/cilastatin during slow hemodialysis in critically ill patients.

The pharmacokinetics of imipenem/cilastatin were determined in 7 critically ill patients undergoing slow hemodialysis (HD). All patients were anuric. Following intravenous administration of 500 mg of imipenem/cilastatin, concentrations of the drugs in the serum and dialysate were monitored during slow HD. The elimination phase half-life of imipenem was 3.1 +/- 0.3 h and that of cilastatin was 9.7 +/- 1.2 h. The total body clearance of imipenem and cilastatin was 84.0 +/- 7.2 and 32.2 +/- 2.4 ml/min, respectively. Clearance of imipenem and cilastatin during slow HD was 24.3 +/- 2.4 and 54.3 +/- 3.1%, respectively, of total body clearance. After the 10.5-h session of slow HD, serum concentrations of imipenem and cilastatin were 2.3 +/- 0.4 and 16.0 +/- 1.2 mg/l, respectively. It appears that at least 500 mg of imipenem may be needed as a supplemental dose after a session of slow HD or the application interval should be shortened to maintain a therapeutic concentration.

Aged↗