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Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 559 records · Page 31Linked to original sources
PubMed1993

Neuropathological study on cerebellum of macular mutant mouse heterozygote.

The hemizygote of the macular mutant mouse is clinically, biochemically and neuropathologically similar to a patient with Menkes kinky hair disease. The heterozygote of this mutant mouse was biochemically and neuropathologically examined. The copper content in the brain decreased in comparison with that in the normal littermate, although it was more than that in the hemizygote. In the Golgi study, abnormal Purkinje cells with somal sprouts, thick stem dendrites and dendritic focal swellings, which were seen in the hemizygote, were not observed in the heterozygote. Ultrastructurally, abnormal mitochondria were seen in the Purkinje cells in the anterior and middle cerebellar lobe of the heterozygote. Histochemically, cytochrome c oxidase activity decreased, especially at the anterior lobe in the cerebellar cortex of the heterozygote. This activity, as indicated by staining intensity, was in between that in the normal littermate and that in the hemizygote. The heterozygote did not show a mosaic pattern in the distribution of these neuropathological changes, although this mutant mouse shows x-linked recessive inheritance. Thus, our results lead to the conclusion that the neuropathological changes observed in this mutant mouse do not result directly from an abnormal gene in the Purkinje cell, but from the secondary effects of subsequent to presumptive copper deficiency.

Animals↗
PubMed1993

Early ependymal changes in experimental hydrocephalus after mumps virus inoculation in hamsters.

To elucidate the pathogenesis of early ventricular dilatation in hydrocephalus, we examined early morphological changes in ependymal layers at the lateral ventricles in suckling hamsters without aqueductal stenosis 5 days after the intracerebral inoculation of mumps virus. Mumps virus antigen was detectable in all ependymal cells. The ependymal cilia had almost disappeared and only the microvilli remained. A number of supraependymal cells were also observed on the surface of the lateral ventricles. Transmission electron microscopy revealed intracytoplasmic viral-like inclusions in the infected ependymal cells. These results suggest that functional and morphological disturbances in infected ependymal cells may cause early ventricular dilatation before aqueductal stenosis occurs.

Animals↗
PubMed1993

Open and closed suction drainage after hepatic resection.

A retrospective study was conducted to compare open conduit drains with closed suction drains, with regard to the occurrence of intraperitoneal septic complications after hepatectomy (IPSCH). The subjects comprised 50 consecutive Japanese patients who underwent hepatic resection followed by the insertion of a closed suction drain and the control group comprised 50 patients in whom a simple conduit drain had been placed following liver surgery. There were no significant differences between the two groups in sex, age, underlying liver disease, or the type of hepatectomy performed; nor was there a significant difference in the incidence of IPSCH, the simple conduit drain group versus the closed suction drain group being (10% versus 8%, respectively). However, bile leakage was highly related to IPSCH, the incidence being 60% and 100% in the simple conduit drain and closed suction drain groups, respectively. Thus, to prevent IPSCH, the treatment of bile leakage is a much more important factor than the type of drain used.

Aged↗
PubMed1993

The significance of methicillin-resistant Staphylococcus aureus infection in general surgery: a multivariate analysis of risk factors and preventive approaches.

To investigate the characteristics, risk factors, and prevention of methicillin-resistant Staphylococcus aureus (MRSA), a total of 3,627 patients were studied. Among these, 1,336 patients with various infections were used in a risk factor analysis of MRSA to determine the relationship between the use of antibiotics and the incidence of MRSA. Only 3.0% of infections were attributed to MRSA, the esophagus and colorectal region being highly involved, as anastomotic or pelvic abscesses, while the lung had a lower incidence. Almost half the patients with MRSA infections (47.6%) had concomitant infection. A univariate analysis revealed the following significant factors: The coexistence of gastrointestinal or metastatic malignancy, sepsis, tracheostomy, and the prior use of antibiotics such as the beta-lactam compounds or aminoglycosides. A multivariate analysis showed that gastrointestinal malignancy, sepsis, and the prior use of aminoglycosides, tetracycline, macrolides, and carbapenems were independently significant factors. To promote the education of doctors and nurses, regular in-service meetings on MRSA were held in the ward. Moreover, preventive approaches such as patient isolation, strategically placed hand washing equipment, and the use of disposable gloves and contaminated waste bags, have been initiated, and the incidence of MRSA has decreased significantly since then. Thus, to control MRSA, the following steps should be taken: (1) constant and careful surveillance, (2) regular risk factor analyses, (3) the optimal administration of antibiotics, and (4) the education of all hospital staff.

Cross Infection↗
PubMed1993

Prediction of hepatic graft viability before reperfusion: an analysis of effluent from porcine allografts.

Rapid and reliable assessment of hepatic graft viability is important for successful orthotopic liver transplantation (OLTx). OLTx was performed in 11 pairs of pigs via a venovenous bypass. Six of these grafts were transplanted immediately (group A), while the other five were preserved in University of Wisconsin (UW) solution for 24 h and then transplanted (group B). All grafts were flushed with 300 ml of chilled (4 degrees C) Ringer's lactate solution before reperfusion of the graft, when 20 ml of effluent from the graft was collected and the concentrations of ammonia, lactic acid, GOT, and LDH were measured. Four of the six pigs in group A survived longer than 3 days, while the other two pigs died of causes other than graft dysfunction. All five pigs in group B died either of hemoperitoneum or hemodynamic instability due to liver failure. The histology of postperfusion biopsies in group A showed minimal pathological changes, while the grafts in group B revealed moderate to severe ischemic injuries. Ammonia and lactic acid in the effluent of group B were significantly higher than those of group A (1511 +/- 216 vs 417 +/- 333 micrograms/dl and 114.1 +/- 12.2 vs 91.4 +/- 12.2 mg/dl, respectively; P < 0.05 in both cases). Before reperfusion, the rate of total adenine nucleotides in all of the substances in the graft, which were measured using high performance liquid chromatography (HPLC), inversely correlated with the ammonia levels in the effluent. We conclude that an analysis of the effluent, (i.e. the levels of ammonia and lactic acid), flushed from a hepatic graft before reperfusion could serve as a predictor of hepatic graft viability.

Adenine Nucleotides↗
PubMed1993

Changes in free and total catecholamine concentrations in plasma in patients undergoing coronary artery bypass grafting under high-dose fentanyl anesthesia.

We measured free and total catecholamine in ten patients undergoing coronary artery-bypass grafting under high-dose fentanyl (93.9 +/- 2.2 microg.kg(-1), mean +/- SE) anesthesia. Arterial blood samples were obtained: 1) before induction of anesthesia (control), 2) 1 min after intubation, 3) 1 min after skin incision, 4) 1 min after median sternotomy and, 5) just before termination of cardiopulmonary bypass (CPB). The concentrations of free and total catecholamine were measured by HPLC using fully automated analyzer, 8030-TOHSO. Free and total catecholamine concentrations did not change significantly before CPB. At the termination of CPB, however, the levels in free dopamine, norepinephrine and epinephrine all increased several fold as compared with control. Similarly, total norepinephrine and epinephrine also increased at the end of PCB, while total dopamine did not change. Present results indicated that 1) the measurement of free CAs is more significant than the measurement of total CAs for the assessment of sympathoadrenal responses to surgical stimuli, and that 2) high-doses of fentanyl produce hemodynamic stability by suppressing sympathoadrenal responses elicited by the usual surgical procedures. However, stress triggered by CPB could not be suppressed totally by fentanyl even with high dose.

Journal Article↗
PubMed1993

E.s.r. study of the conformational transition of spin-labelled xanthan gum in aqueous solution.

The order to disorder transition of xanthan molecules in aqueous solutions has been studied using e.s.r. spectroscopy. Nitroxide spin-label was covalently attached to carboxyl groups on the xanthan side chains. The e.s.r. spectra obtained for aqueous spin-labelled xanthan solutions at varying ionic strengths contained both isotropic and anisotropic components at room temperature. The anisotropic component was attributed to the association of the side chains with the xanthan cellulosic backbone and was found to be present in greater proportions at increasing ionic strength. The spectra gradually changed with rising temperature and the proportion of anisotropic component decreased. This spectral change reflected the disruption of the side chain association with the backbone during the conformational change. Hysteresis effects were observed following sequential heating and cooling cycles suggesting that chain aggregation occurred.

Electron Spin Resonance Spectroscopy↗
PubMed1993

Suppression of natural killer cell activity by granulocytes in patients with aplastic anemia: role of granulocyte colony-stimulating factor.

Patients with aplastic anemia were tested for natural killer (NK) activity, and the roles of granulocytes and granulocyte colony-stimulating factor (G-CSF) in the regulation of cytotoxicity were evaluated. Blood lymphocytes showed low or no NK activity against K562 targets. The depression of NK activity was more frequently recorded for patients who were not in remission and those who received G-CSF administration. Granulocytes of aplastic anemia patients with impaired NK activity suppressed the lytic activity of NK cells. By contrast, granulocytes from normal controls and aplastic anemia patients with normal NK activity had no suppressive activity. There was a good correlation between NK activity of lymphocytes and suppressive activity of granulocytes. Blocking of direct contact of suppressor and effector cells by cell chambers abolished suppression of cytotoxicity. NK suppression by granulocytes was resistant to treatment with catalase or superoxide dismutase. In vitro stimulation with G-CSF of granulocytes that naturally had no suppressive activity resulted in development of suppressive function, whereas granulocytes with natural suppressive activity were not further stimulated in vitro by G-CSF to express augmented activity. These results suggest that the presence of suppressor granulocytes in the blood could be one cause of the impaired NK activity in patients with aplastic anemia.

Adolescent↗
PubMed1993

Effect of anesthesia and surgery on plasma cytokine levels.

Cytokines released in response to stress may have a profound impact on circulatory stability. There is no information on the effect of general anesthesia alone on plasma cytokine levels and little information on cytokine release following surgery. Plasma cytokine levels and hemodynamic parameters were measured during anesthesia and abdominal surgery under sterile and nonpyrogenic conditions in seven pigs anesthetized with ketamine and pentobarbital. Tumor necrosis factor (TNF) was measured by bioassay. Bioassays of low and high sensitivity were used to measure interleukin 6 (IL-6). Measurements were made sequentially during: (1) 4 hours observation with anesthesia alone; (2) 2 hours following laparotomy and traumatic intestinal manipulation (IM) sufficient to produce shock; and (3) after an intravenous bolus of 1 microgram/kg endotoxin as a positive control. Arterial blood pressure decreased following IM from 91.5 +/- 5.8 to 48.6 +/- 3.2 mm Hg, (mean +/- SE, P < .05), with no further change following endotoxin. Heart rate was unchanged during the experiment, and central venous pressure decreased after endotoxin (P < .05). There were no increases in TNF or IL-6 (using a low sensitivity assay) with anesthesia alone or following IM with shock, but both increased after endotoxin administration (P < .05); using a high sensitivity assay, IL-6 did not change during anesthesia alone but did increase fivefold following IM with shock (P < .05) and 50-fold following endotoxin administration (P < .05). We conclude that in a porcine model under sterile and nonpyrogenic conditions, prolonged anesthesia does not increase plasma cytokine levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1993

Alternate hemihepatic vascular control technique for hepatic resection.

This report describes a simple and improved inflow control technique for resection of a hepatic tumor that lies across the right and left hepatic lobes. With alternate hemihepatic inflow control by en masse occlusion of Glisson's sheath of each hemipedicle at the bifurcation, hepatic resection across the two hepatic lobes is completed. Compared with Pringle's maneuver, this technique eliminates splanchnic congestion and reduces warm ischemia of the remnant liver, while maintaining a comparable hemostatic effect.

Humans↗
PubMed1993

Apolipoprotein E metabolism in sciatic nerves of diabetic rats. Implication for diabetic neuropathy.

Apolipoprotein (apo) E secreted by macrophages plays an important role in nerve injury and repair. We investigated the disturbance of neural apo E metabolism in diabetic rats and its relation to diabetic neuropathy. In BB/W rats, genetically diabetes prone rats, the secretion of apo E from sciatic nerves was 3-fold greater than that in control rats. Furthermore, a similar enhancement of apo E secretion was observed in injured nerves of STZ-induced diabetic rats (2-fold) as compared with those of nondiabetic rats, and this was reversible with insulin treatment. Histological examination of the nerves revealed more extensive infiltration of mononuclear cells in the injured nerves of STZ-induced diabetic rats than in those of non-diabetic rats. This is consistent with the findings that chemotactic activities for mononuclear cells, which were released from injured nerves, were greater in the STZ-induced diabetic rats than in the non-diabetic rats. From these results we conclude that the recruitment of monocyte/macrophages into injured nerves is enhanced in diabetes, thereby causing derangement of neural apo E metabolism. These abnormalities might contribute to the development of diabetic neuropathy.

Adult↗
PubMed1993

Regulation of acute phase gene expression following surgery and endotoxin administration in the anesthetized pig.

BACKGROUND: The hepatic acute phase response (APR) reflects an organism's integrated response to stress. This APR results in augmented synthesis and secretion of specific procoagulants and antiproteases and a complementary decrease in the synthesis and secretion of several constitutive proteins, such as albumin. The cytokines tumor necrosis factor (TNF) or interleukin-6 (IL-6) have been identified as proximal mediators of the APR in response to endotoxin stress. The authors hypothesized that TNF, IL-6, or both would be the proximal mediators of the APR in response to anesthesia and surgical stress. METHODS: The effects of a standardized surgical stress on the APR in pigs under general anesthesia with sodium pentobarbital and ketamine hydrochloride was investigated. Acute phase gene transcription was assayed in nuclei from serial liver biopsies obtained before and after 2.5 h of surgical stress, and after endotoxin administration. Tumor necrosis factor and IL-6 mRNA levels in this liver tissue were examined by Northern blot hybridization, and simultaneous plasma levels of these cytokines were measured using bioassays. RESULTS: The transcription rates of three positive acute phase genes--chymotrypsin inhibitor, inter-alpha-trypsin inhibitor and beta-fibrinogen--increased seven-, six-, and twofold, respectively (P < 0.05), and the transcription rate of albumin, a negative acute phase gene, decreased to 34% of baseline (P < 0.01) during the 2.5 h of anesthesia and surgical stress. During this initial 2.5 h, plasma concentrations of TNF and IL-6 did not change. Hepatic IL-6 mRNA expression was never observed, and TNF mRNA expression was undetectable in six of seven pigs. Subsequent 10-micrograms/kg endotoxin administration caused 20- and 100-fold increases in plasma concentrations of TNF and IL-6, respectively (P < 0.01), and were associated with substantial hepatic expression of the TNF and IL-6 mRNAs. These increments in cytokines were not associated with any further increase in the acute phase gene transcription rates. Thus, the APR was initially regulated at the transcriptional level during surgical stress independent of, and not augmentable by, an endotoxin-provoked increase in either plasma levels or hepatic mRNA expression of TNF or IL-6. CONCLUSIONS: Surgical stress induced hepatic acute phase gene transcription within 2.5 h in the absence of either systemic or local (hepatic) increases in TNF or IL-6. Subsequent endotoxin-induced increases in TNF or IL-6 did not alter this surgical stress-induced acute phase gene transcription.

Acute-Phase Proteins↗
PubMed1993

Identification of two distinct NADH oxidases corresponding to H2O2-forming oxidase and H2O-forming oxidase induced in Streptococcus mutans.

Two distinct NADH oxidases, corresponding to H2O2-forming and H2O-forming enzymes were purified to homogeneity from Streptococcus mutans and their basic properties determined. The H2O2-forming enzyme was a tetramer with a subunit molecular mass of about 56 kDa and required flavin adenine dinucleotide (FAD) for full activity. The enzyme had an isoelectric point of 6.6 and exhibited optimal activity at pH 6.0. The H2O-forming enzyme was a monomer with a molecular mass of 50 kDa and activity independent of exogenously added flavin. The enzyme had an isoelectric point of 4.8 and exhibited optimal activity between pH 7.0 and 7.5. Both enzymes oxidized NADH (Km 0.05 and 0.025 mM for the H2O2- and H2O-forming enzyme, respectively) but not NADPH and contained 1 mol of FAD per monomer. Spectra of the oxidized enzymes exhibited maxima at 271, 383 and 449 nm for the H2O2-forming enzyme and 271, 375 and 447 nm for the H2O-forming enzyme. Antibodies raised against the H2O2-forming enzyme or the H2O-forming enzyme reacted with their corresponding antigen, but did not cross-react. The amino-terminal regions of the two enzymes had completely different amino acid sequences.

Amino Acid Sequence↗
PubMed1993

Contribution of rib cage and abdominal movement to ventilation for successful weaning from mechanical ventilation.

In order to test the hypothesis whether the breathing pattern is helpful in predicting weaning outcome in patients being weaned from mechanical ventilation, 38 patients who underwent operation for esophageal cancer were evaluated at weaning from mechanical ventilation (19 unsuccessful weanings, group U, and 19 successful weanings in age-matched patients, group S). Since all patients initially fulfilled our weaning criteria, ventilatory parameters such as tidal volume, respiratory frequency, minute ventilation, and arterial blood gas analysis showed no significant differences between the groups. The breathing pattern was registered quantitatively by means of respiratory inductive plethysmography at 3 cmH2O (0.3 kPa) of CPAP prior to weaning. The contribution of rib cage movement to tidal volume (%RC) was significantly greater in group U than in group S (P < 0.05). Indeed, 84% of the patients in group S showed %RC less than 50%, compared to only 16% of the patients in group U (P < 0.05). The results suggest that the breathing pattern is one important factor in predicting the outcome of weaning in patients after thoraco-abdominal surgery. Diaphragmatic fatigue is suspected to be the mechanism for the increase in the RC component in patients with unsuccessful weaning outcome.

Abdomen↗
PubMed1993

Rheumatoid arthritis and B cell lymphoma with pathological changes of reactive histiocytosis.

A 67 year old woman with rheumatoid arthritis was admitted to hospital in acute renal failure. Her clinical features included increasing dyspnoea and oedema, and a computed tomogram of the abdomen showed a large mass in the retroperitoneum. Twenty six days later, she died, and a post mortem examination was carried out. The histological changes of the mass indicated B cell lymphoma of diffuse large cell type, with a reactive proliferation of erythrophagocytosing histiocytes. Immunocytochemical studies showed that the histiocytes were positive for CD-68 and lysozyme, but negative for S-100 protein. Such neoplastic B cell proliferation accompanied by activation of benign looking histiocytes with erythrophagocytosis is very rare.

Aged↗
PubMed1993

A safe and simple technique for exchanging central venous catheters.

A safe and simple technique for exchanging central venous catheters is herein described. Our technique is based on a modification of Seldinger's method, in which a new outer sheath is introduced over the previous catheter as a guidewire in order to simplify the exchange of central venous catheters. This technique can be successfully performed by new residents and can be applied to the exchange of clotted catheters.

Catheterization, Central Venous↗
PubMed1993

Macrophage colony-stimulating factor regulates both activities of neutral and acidic cholesteryl ester hydrolases in human monocyte-derived macrophages.

Macrophage colony-stimulating factor (M-CSF) regulates cholesterol metabolism in vivo and in vitro. We studied the effects of M-CSF on enzyme activities of acidic cholesteryl ester (CE) hydrolase, neutral CE hydrolase, and acyl-coenzyme A:cholesterol acyltransferase (ACAT), all of which are involved in cellular cholesterol metabolism in macrophages. During the differentiation of monocytes to macrophages, these enzyme activities were induced and further enhanced in response to M-CSF. M-CSF (100 ng/ml) enhanced acidic and neutral CE hydrolase and ACAT activities by 3.2-, 4-, and 2.3-fold, respectively, in the presence of acetyl LDL. The presence of acetyl LDL influenced these enzyme activities. ACAT and acidic CE hydrolase activities were increased and neutral CE hydrolase activity was decreased, indicating that these enzymes are regulated by intracellular cholesterol enrichment. M-CSF increased the ratios of acidic CE hydrolase to ACAT activity and of neutral CE hydrolase to ACAT activity. The results suggest that M-CSF enhances net hydrolysis of CE by stimulating the two CE hydrolases to a greater extent than ACAT, and M-CSF may reduce the rate of atherogenesis.

Base Sequence↗