Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 523 records · Page 29Linked to original sources

PubMed1994

Primary structure and molecular basis of polymorphic appearance of an acetyltransferase (AT-II)* in hamsters.

Three hamster clones (clones 1, 2 and 3) were isolated from a genomic library constructed from a homozygote rapid acetylator using a cDNA (hamAT-101) of a monomorphic acetyltransferase (AT-I) as a probe. Clone 1 (13 kbp) was found to contain a gene corresponding to AT-I. The entire coding region was located in an exon and completely identical to that of AT-I cDNA. Clones 2 and 3 (14.5 and 15 kbp) each contained identical information to the AT-I-related protein (AT-B protein). The intronless coding region shared 83.7% of sequence similarly to the AT-I cDNA, and its length was identical to that of the AT-I cDNA. Clone 2 also included a nucleotide sequence identical to the 3'-portion of the AT-I gene, which is located 5'-upstream of the AT-B gene. Restricted fragment lengths of clone 3, which encompassed the entire coding region was expressed in COS-1 cells. The expressed protein migrated at a position identical to that of AT-II purified from a hamster liver on Western blots. AT-B-expressed protein catalysed acetyl CoA-dependent N-acetylation of 2-aminofluorene and p-aminobenzoic acid, but had marginal activities for O-acetylation of 2-N-hydroxyamino-6-methyl-6-methyldipyrido[1,2-a:3',2'-d]imidazole and N-hydroxyarylacetamide-dependent N-acetylation of 4-aminoazobenzene. These results are in good agreement with the data of AT-II purified from hamster livers, indicating that the AT-B gene encodes a polymorphic acetyltransferase (AT-II) in hamsters. Although the AT-II protein was undetectable in slow acetylators, specific mRNA, hybridizing with a selective oligonucleotide probe for the AT-II gene (AT-B), was detected in livers of both homozygous acetylators. Analysis of genomic DNA of a homozygous slow phenotype hamster indicates that AT-II DNA from the slow phenotype has a point mutation which causes premature termination at the 243th (Arg to stop codon) position of the deduced amino acid sequence. PCR-RFLP analysis further confirmed that the point mutation conferred a defective AT-II protein in slow phenotype hamsters.

4-Aminobenzoic Acid↗

PubMed1994

Detection of human cytomegalovirus DNA in breast milk by means of polymerase chain reaction.

Three hundred and twenty-five breast milk samples were examined for the occurrence of human cytomegalovirus (HCMV) by cell culture method. Virus was isolated from the milk in 1 of 177 samples collected within 6 days after delivery, 2 of 115 samples collected during the period of 7 days to 1 month after delivery, 10 of 33 samples collected over 1 month after delivery. Next, we tried to amplify HCMV DNA from the breast milk samples from HCMV seropositive mothers and seronegative mothers at 1 month after delivery by polymerase chain reaction. HCMV DNA was detected in 12 of 13 samples from seropositive mothers and in none of 7 samples from seronegative mothers. It was thought that all women seropositive for HCMV principally shed the virus into their breast milk at 1 month after delivery.

Antibodies, Viral↗

PubMed1994

Detection of alcohol-tolerant hiochi bacteria by PCR.

We report a sensitive and rapid method for detection of hiochi bacteria by PCR. This method involves the electrophoresis of amplified DNA. Nucleotide sequences of the spacer region between 16S and 23S rRNA genes of 11 Lactobacillus strains were identified by analysis of PCR products. Five primers were designed by analysis of similarities among these sequences. A single cell of Lactobacillus casei subsp. casei could be detected when purified genomic DNA was used as the template. When various cell concentrations of L. casei subsp. casei were added to 50 ml of pasteurized sake and the cells were recovered, the detection limit was about one cell. No discrete band was observed in electrophoresis after PCR when human, Escherichia coli, mycoplasma, Acholeplasma, yeast, or mold DNA was used as the template.

Bacteriological Techniques↗

PubMed1994

Strategies for reducing blood transfusions in hepatic resection.

A comparison of 60 blood transfused and 71 nonblood transfused hepatic resection patients was done to evaluate strategies for reducing blood transfusions during hepatic surgery. There were no significant differences between the two groups with regard to preoperative laboratory data, except for prothrombin time and hematocrit value. The mean operative blood loss was 1990 ml and 760 ml in the blood transfused and nonblood transfused groups, respectively. A multivariate analysis suggested that the patient's body weight, preoperative prothrombin time, and operative blood loss independently predicted the need for intraoperative blood transfusion. Major postoperative complications developed more frequently in the blood transfused group than in the nonblood transfused group (31.7 vs. 11.3%, p < 0.005). These results suggest that the difference in operative blood loss between the two groups was related to the prolonged prothrombin time and a susceptibility for blood transfusion was found to exist particularly in patients with a lower hematocrit value as well as a lower body weight. Thus, the improvement of these preoperative laboratory data combined with avoiding the use of the hematocrit value as a determining factor for intraoperative transfusion could correspond to a reduction in operative blood loss, while curtailing the demands on blood bank facilities, and lowering the risk of postoperative complications.

Adult↗

PubMed1994

Copper distribution in fetus and placenta of the macular mutant mouse as a model of Menkes kinky hair disease.

Menkes kinky hair disease (MKHD) in humans is caused by a disturbance in copper homeostasis. A mutant mouse shows clinical and biochemical features very close to MKHD. In an attempt to elucidate the defect in copper transport, the copper distribution in various organs of 18-gestational-day-old macular mouse embryos, following administration by a single injection of saline (control) or 50 micrograms of CuCl2 on day 16 of gestation or by two injections on days 15 and 17 of gestation to the dams, was examined both biochemically and histochemically. The copper content in the hemizygous fetus (Ml/y) born to the homozygous mother, who had no copper injection during gestation, was lower in the brain and liver but higher in the placenta than in the respective organs of the normal fetus. When 50 micrograms of CuCl2 was injected into heterozygous dams (Ml/+) on day 16 of gestation, their hemizygous fetuses showed a slight increase in the copper content in the brain and liver, but the amount of copper in these organs was still less than that of the normal fetus. Conversely, the copper content in the placenta of the hemizygous fetus was far higher than that of the normal fetus. In the copper staining of the fetuses harvested from heterozygous dams, some fetuses showed copper deposition in the placenta, but not in the liver. The others showed no copper deposit in both the placenta and liver, thus indicating that the former were hemizygous for the mutation and the latter were normal littermates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Overexpression of human lipoprotein lipase enhances uptake of lipoproteins containing apolipoprotein B-100 in transfected cells.

To investigate the role in lipoprotein metabolism of lipoprotein lipase (LPL) secreted by tissues, we established two cell lines. Fusion plasmids containing either human LPL cDNA or antisense LPL cDNA under control of the cytomegalovirus promoter were transfected into Chinese hamster ovary (CHO) cells, designated as CHO-LPL and CHO-anti-LPL, respectively. CHO-LPL constitutively produced a high level of LPL, whereas CHO-anti-LPL produced a minimal level. When very-low-density lipoprotein (VLDL) was incubated with CHO-LPL, VLDL triglycerides were hydrolyzed, intermediate-density lipoprotein (IDL) was produced, and apolipoprotein E contents increased. CHO-LPL took up and degraded 125I-VLDL at 37 degrees C four times more strongly than did CHO-anti-LPL. Whereas the degradation of apolipoprotein E-deficient VLDL was only 12% that of normal VLDL in CHO-LPL, structural changes of the lipoprotein, including apolipoprotein E expression on the lipoprotein surface, may be important for the cellular uptake of VLDL. Furthermore, we found that binding at 4 degrees C of VLDL and LDL to CHO-LPL was greater than to CHO-anti-LPL, and this binding difference was abolished by washing the cells with heparin. This suggests that cell surface LPL plays a role in the binding of lipoproteins to the cells. We conclude that both the composition of VLDL particles and their cellular binding are influenced by LPL secreted by cells, both of which may enhance the cellular uptake of VLDL.

Animals↗

PubMed1994

Secretion-recapture process of apolipoprotein E in hepatic uptake of chylomicron remnants in transgenic mice.

To investigate the role of apoE in hepatic uptake of chylomicron remnants, we studied chylomicron metabolism in transgenic mice overexpressing apoE in the liver. Plasma clearance of injected 125I-labeled human chylomicrons was fivefold faster in transgenic mice than in controls. Immunohistochemistry demonstrated that apoE was specifically localized at the basolateral surface of hepatocytes from fasted transgenic mice. After injection of a large amount of chylomicrons, the density of the cell surface apoE was markedly reduced and vesicular staining was observed in the cytoplasm, suggesting that the cell surface apoE was used for hepatic endocytosis of chylomicrons and remnants. Polyacrylamide gel analysis of chylomicrons and remnants that had been reisolated from plasma and from liver membrane after the injection of chylomicrons showed the particles to be enriched with apoE mainly after their influx into the liver rather than during their residence in plasma. These results provide strong evidence for the secretion-recapture process of apoE, whereby chylomicron remnants enter the sinusoidal space, acquire apoE molecules, and subsequently are endocytosed. Data from experiments with very low density lipoprotein and LDL showed that this system is specific for chylomicron remnants.

Animals↗

PubMed1994

Molecular cloning and sequence analysis of the gene encoding the H2O2-forming NADH oxidase from Streptococcus mutans.

Streptococcus mutans induces both H2O2-forming and H2O-forming NADH oxidases in the presence of O2 [M. Higuchi, J. Gen. Microbiol., 130, 1819-1826 (1984)]. In this paper, a nox-1 gene encoding H2O2-forming NADH oxidase (NOX-1) from Streptococcus mutans was cloned, and the nucleotides sequenced. The structural gene of nox-1 consisted of 1530 base pairs, which encode a polypeptide consisting of 510 amino acids with a predicted molecular mass of 55,196 Da. The deduced N-terminal amino acid sequence was consistent with that previously found for the purified NOX-1 protein. The nox-1 gene was expressed in Escherichia coli using its own promoter. Alignment of the amino acid sequence of NOX-1 with those of NADH oxidases from other microorganisms showed identities of 55.6%, 20.8%, 20.3%, and 7.3% for those of Amphibacillus xylanus Ep01, Streptococcus faecalis 10C1, Thermoanaerobium brockii Rt8.G4, and Thermus thermophilus HB8, respectively.

Amino Acid Sequence↗

PubMed1994

[Drug distribution and antitumor effect of bleomycin incorporated in poly DL-lactic acid in rats].

Two bleomycin (BLM)-containing agents (BLM-PLA, BLM-SOL) were prepared, and the drug distribution and antitumor effect were studied. BLM-PLA is an agent in which BLM is incorporated into biodegradable low-molecular-weight polylactic acid, and BLM-SOL is an aqueous solution of BLM. BLM-PLA or BLM-SOL was subcutaneously administered in the back of rats. When BLM-PLA was implanted, high BLM activity of the connective tissues near the implants was maintained for 2 weeks. On the other hand, BLM activity was very low when BLM-SOL was administered. The effects of BLM-PLA, BLM-SOL and nontreatment on tumor growth and survival time were compared using subcutaneous tumor of Yoshida sarcoma in 21 rats each. The survivors and mean survival time in BLM-PLA group, BLM-SOL group and nontreatment group was 14 and 44.6 days, 5 and 23.7 days, and 0 and 11.3 days, respectively. BLM-PLA was superior to BLM-SOL in both drug distribution and antitumor effect, and consequently BLM-PLA could be a useful tool in loco-regional chemotherapy.

Animals↗

PubMed1994

Establishment of enzyme-linked immunosorbent assays for lipoprotein lipase with newly developed antibodies.

We developed eight new antibodies against lipoprotein lipase (LPL), which included polyclonal antibodies raised against recombinant human LPL produced by transformant cells and two synthetic peptides corresponding to either amino (N)- or carboxy (C)-terminus of human LPL. With these antibodies, we established three effective sandwich enzyme-linked immunosorbent assays (ELISAs) for LPL, which enabled us to examine LPL mass not only in the postheparin plasma from human, rat, mouse, and guinea pig but also in the media and lysates of cultured cells. All of the developed antibodies showed high affinities for LPL, but their binding to LPL did not always influence the lipolytic activity of the enzyme. Interestingly, although the anti-C-terminus antibody should bind to a common epitope of human and mouse LPL, its binding selectively suppressed only human LPL activity. Because amino acid sequence surrounding the epitope is common to both LPLs, difference in the sequence outside the epitope will contribute to the selective suppression of LPL activity by the antibody. Our results also suggested that both termini of LPL would be exposed on the surface of the molecule because they were fully accessible to antibodies and that the N-terminus of LPL would be functionally less important because binding of the anti-N-terminus antibody did not affect human LPL activity. The ELISAs were further utilized to demonstrate the presence of C-terminus truncated LPL protein in the postheparin plasma of an LPL-deficient patient, to map an epitope of the anti-C-terminus antibody within residues 433-436, and to gain insight into the structure-function relationship of the LPL molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Effect of mebendazole on free amino acid composition of cyst wall and cyst fluid of Echinococcus granulosus harbored in mice.

Eighteen and 23 FAA components were detected in the cyst wall and cyst fluid of E granulosus, respectively, by using automatic amino acid analyzer. The concentrations of most of the determined FAA were higher in the cyst fluid than those in the cyst wall, especially the taurine was 5-fold higher. Mebendazole treatment resulted in an increase in the concentration of alanine, valine, lysine, and taurine in both cyst wall and cyst fluid, the most notable being the alanine in the cyst wall. The results are interpreted as a coupling of glycolysis and amino acid metabolism, suggesting an involvement of FAA metabolism in the mechanism of Meb action.

Alanine↗

PubMed1994

[Two cases of esophageal fistula, in which a fibrin glue preparation was effective].

Two successful cases of endoscopic therapy for esophageal fistula are reported herein. The first case was a 61-year-old man who underwent irradiation, chemotherapy and endoscopic laser beam therapy for esophageal cancer (Im T4N0M0 Stage III). Gastrografin -esophagogram revealed a fistula between esophagus and mediastinum after these therapy. Closure of the fistula was attainable using fibrin glue with a double-channel-fiber scope. The second case was a 43-year-old man who underwent chemotherapy and irradiation for lung cancer (S1,S2 T4N2M0 Stage IIIB) which invaded to mediastinum, trachea and esophagus. Bronchogram revealed a esophago-tracheal fistula one month later. We performed the same procedure as the first case, and confirmed reduction of the fistulous size. The endoscopic fibrin glue injection is an easy, safe and effective technique for the fistula even caused by malignancies, and contributes to the quality of life of these patients.

Adult↗

PubMed1994

Major hepatic resection in patients with a prosthetic heart valve receiving anticoagulation treatment.

We experienced two patients with a prosthetic heart valve, who underwent hepatic resection for hepatoma while on anticoagulation therapy. Patients with a prosthetic heart valve have the following characteristics; an increased risk of thromboembolism due to diminished anticoagulation in the perioperative period, a greater risk of endocarditis due to the artificial material in the heart, and impaired cardiopulmonary function including possible arrhythmia and heart failure. Furthermore, when such patients also have liver cirrhosis with a hepatoma, there is an increased risk of perioperative bleeding while on anticoagulation due to coagulopathy and also a risk of infection due to decreased cellular immunity. Patients with a prosthetic heart valve therefore require special care and attention whenever they have to undergo hepatic resection. With respect to anticoagulation, a minimal level is required to prevent bleeding and thromboembolism. Warfarin being administered preoperatively may be switched to heparin while closely monitoring the activated clotting time (biomaterial valve: 130-150 sec, non-biomaterial valve: 150-180 sec); the heparin should then be changed back to warfarin immediately after starting oral intake following operation. For the prevention of infection, a broad spectrum antibiotic should be used prophylactically both intra-operatively and postoperatively. The cardiopulmonary function must also be carefully monitored. For the assessment of postoperative liver function, lecithin: cholesterol acyltransferase, serum bilirubin and albumin are useful because there is no relevance of coagulation parameters such as prothrombin time under anticoagulation.

Carcinoma, Hepatocellular↗

PubMed1994

Effects of mass screening for neuroblastoma and the presumptive natural history of this tumor.

1) By March 1992, 166,959 infants were screened in Sapporo City, and 35 patients were found to have this tumor. Incidence of this tumor in our screening was one among 5,059 babies examined. 2) Eleven infants among the group with negative screening at 6 months developed neuroblastoma later. The patients developed tumors one to several years after mass screening, and 2/3 of these cases showed high urinary HVA compared to VMA. 3) We postulate that some of the adrenal steroids, possibly cortisol, may play a role for the malignant progression of this tumor.

Adolescent↗

PubMed1994

Reproductive toxicity studies of the new cognition-enhancing agent nefiracetam in rats and rabbits.

The reproductive toxicity of nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, DM-9384, CAS 77191-36-7) was investigated in rats and rabbits. Nefiracetam was administered orally for 9 weeks or more until successful copulation to male rats at doses of up to 480 mg/kg/d. Female rats were treated with nefiracetam at the same doses for more than 2 weeks prior to and in the early stages of pregnancy. No adverse effects on fertility were noted at any dose level. Nefiracetam elicited no evidence of teratogenicity when administered during the fetal organogenesis period to pregnant rats at doses of up to 1000 mg/kg/d, or to pregnant rabbits at doses of up to 270 mg/kg/d. Rat fetuses in the 1000 mg/kg group exhibited decreased body weights, delayed ossification and an increased incidence of skeletal variations such as cervical ribs and shortening of the 13th ribs. Decreased body weight gain and decreased food intake were also noted in rat dams of the 1000 mg/kg group. Nefiracetam showed no adverse effects on postnatal development, behavior or reproductive performance of rat offspring, except for decreased body weight gain in the 1000 mg/kg group. Rabbit fetuses in the 270 mg/kg group exhibited increased skeletal variations, mainly presence of the 13th ribs. Decreased body weight gain and decreased food intake were also noted in rabbit dams of the 270 mg/kg group. In a perinatal and postnatal toxicity study in rats using doses of up to 500 mg/kg, decreased food intakes were noted in dams of the 500 mg/kg group.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗

PubMed1994

Indications for major hepatectomy in cirrhotic liver.

In an investigation of the indications for major hepatic resection of the cirrhotic liver, the records of 152 consecutive patients who had undergone a right hepatic resection between April 1985 and January 1991 were reviewed. A comparison of right hepatic lobectomy and right partial hepatectomy of the liver with no cirrhotic changes, revealed that postoperative values of serum glutamic pyruvic transaminase were significantly higher after right partial hepatectomy than after right lobectomy, despite the fact that there were no significant differences with respect to preoperative laboratory data, and there was a greater blood loss and total weight of the resected liver in patients receiving a right lobectomy as compared with those undergoing partial hepatectomy. These results suggest that in order to enable a more favorable recovery from hepatic resection, it is essential to avoid both mechanical damage and ischemic injury to the residual liver during hepatic surgery. A total of 77 patients underwent a partial hepatectomy of a cirrhotic liver, and among these patients, 16 patients had values of the indocyanine green test of less than 20%, as well as a portal pressure of less than 200 mm saline. Compared with these 16 cirrhotic patients and those patients who underwent right lobectomy, there were no significant differences with regard to the pre-operative laboratory data and portal pressure. These results therefore suggest that major hepatic lobectomy could be performed on selected patients with cirrhotic livers.

Adult↗

PubMed1994

Estimation of degree of liver cirrhosis using a fibrosis score; a multivariate analysis of clinical parameters and resected specimens.

We designed this study to estimate the degree of liver cirrhosis using clinical parameters and surgically resected specimens. One hundred and twenty-nine cases who underwent hepatic resection in the Department of Surgery II, Kyushu University Hospital during the period between April 1985 and July 1991 for whom data for all 29 variables evaluated were available, were admitted to this study. On the basis of the histological findings of fibrosis of the liver, the non-neoplastic part of the resected specimens were classified into 3 groups; Z0, no cirrhosis (n = 63), Z1, mild cirrhosis (n = 38), and Z2, severe cirrhosis (n = 28). A univariate analysis revealed 14 significant variables. After multiple logistic regression analysis of these, five independent variables (low platelet count, female, low value of hepaplastin test, a high Pugh's score and a high value of ICG) were identified. We obtained a fibrosis score using the coefficient of each above-mentioned variable. This score increased the discriminative power. The fibrosis score is therefore considered useful for estimating the severity of liver cirrhosis.

Adult↗

PubMed1994

[Pathogenesis of hypoxic encephalopathy during pre- and peri-natal periods].

Hypoxic encephalopathy during the late gestation and perinatal period occupies a large part as a cause of mentally and physically handicaps. An extensive study on the pathogenesis and pathophysiology of the hypoxic brain damage is, therefore, the matter of urgency to minimize the occurrence of handicapped children. The main factors and/or processes relating to hypoxic or hypoxic-ischemic brain damage are (1) structural and functional immaturity of the brain vascular system and (2) a metabolic cascade triggered by hypoxia. As the following metabolic cascade subsequent to hypoxia has been partly made clear; (a) disturbance of the energy metabolism, (b) excessive release of excitatory amino acids and subsequent activation of NMDA and K/Q receptors at the cell membrane, (c) collapse of the membrane ion pump, and (d) increase in turnover of membrane phospholipids.

Asphyxia Neonatorum↗