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Biomedical subjects

A Koga

Publications and source records attributed to A Koga.

At least 55 records · Page 3Linked to original sources
PubMed1994

Increased sinusoidal efflux of reduced and oxidized glutathione in rats with endotoxin/D-galactosamine hepatitis.

The changes in the concentrations of reduced (GSH) and oxidized glutathione (GSSG) in the plasma as well as in the liver were investigated in rats with endotoxin hepatitis. Hepatitis was induced by intraperitoneal co-administration of small doses of Escherichia coli endotoxin and D-galactosamine. In the liver, the concentration of GSH decreased and that of GSSG increased 12 hr later. In the plasma taken from the right atrium, the concentration of both GSH and GSSG increased. The GSH/GSSG ratio in the plasma decreased, as it did in the liver. The net sinusoidal efflux of GSH and GSSG from the liver was calculated by subtracting their concentrations in plasma of the infrahepatic, suprarenal inferior vena cava from those of the suprahepatic inferior vena cava. The efflux started to increase as early as 2-4 hr after the injection of the toxins. In contrast, a leakage of alanine aminotransferase, an elongation of prothrombin time, an inhibition of starvation ketosis, and an increase in serum concentration of total bilirubin were detected as late as 6-8 hr after the injection. We conclude that endotoxin/D-galactosamine hepatitis induced an increase in plasma concentrations of GSH as well as GSSG by increasing the efflux of these peptides from the liver, and that changes in plasma glutathione status might be useful and sensitive markers for liver damage.

Animals↗
PubMed1993

Distribution of polymorphic gene duplication at the Gpdh locus in natural populations of Drosophila melanogaster.

The glycerol-3-phosphate dehydrogenase (GPDH, E.C. 1.1.1.8) gene of Drosophila melanogaster contains a tandem duplication of a 4.5-kb-long DNA fragment. Survey of the Gpdh gene region by the Southern blot analysis revealed the following features of this gene duplication: (1) The duplication was not observed in chromosome lines that carry In(2L)t, a cosmopolitan chromosomal inversion in this species. The duplication and the inversion are in linkage disequilibrium. (2) The duplication is polymorphic in the Japan and US natural populations examined. Its frequency is 0.26 on an average in In(2L)t-free chromosomes. (3) Triplication is absent or has not become frequent in the populations surveyed. Possible evolutionary factors of this duplication polymorphism are discussed.

Alleles↗
PubMed1993

Surgical management and long-term follow-up of patients with choledochal cysts.

The medical records of 46 patients treated for choledochal cysts at Kyushu University from 1965 to 1990 were reviewed, and long-term follow-up results were evaluated based on the type of cyst and on the choice of surgical procedure. Of 46 patients, 41 (89%) were female and 5 (11%) were male, with a mean age of 24 years at the time of the initial operation. Seventy-eight percent of patients presented with an abdominal pain, 43% with jaundice, and 33% with an abdominal mass. Only seven patients (15%) presented with the classic triad. According to the Todani classification system, 26 patients (57%) had type I cysts, 2 (4%) had type II, and 18 (39%) had type IV. Four patients (9%) had biliary tract carcinoma. At the time of the initial operation, the major associated diseases were cholangitis in 15% and choledocholithiasis in 26% of cases. In 24 patients who had undergone previous cyst enterostomy, cholangitis developed in 88%, choledocholithiasis in 25%, and hepatolithiasis in 33% of patients, indicating a high complication rate after cyst enterostomy. Seventy percent of these patients needed reoperation. In contrast, cyst excision with Roux-en-Y hepaticojejunostomy gave excellent long-term results. Thus, cyst excision with hepaticojejunostomy is the definitive treatment of choice for type I and IV choledochal cysts.

Adolescent↗
PubMed1993

Increase in the plasma concentration of reduced glutathione observed in rats with liver damage induced by lipopolysaccharide/D-galactosamine: effects of ulinastatin, a urinary trypsin inhibitor.

The changes in plasma concentrations of reduced glutathione were investigated in rats with endotoxin hepatitis. An increase in serum alanine aminotransferase activity and in serum total bilirubin concentration was observed 12 hr after the intraperitoneal co-administration of small doses of Escherichia coli lipopolysaccharide and D-galactosamine in starved rats. At the same time, an increase in the plasma concentration of reduced glutathione was also observed. The increase in reduced glutathione from 14 +/- 2 to 20 +/- 9 microM (n = 11, P < 0.05) correlated well with that in serum alanine aminotransferase activity. Ulinastatin, a potent inhibitor of polymorphonuclear leukocyte elastase, partially counteracted all of these changes. Ulinastatin also reduced histological liver damage induced by endotoxin. We conclude that the increase in the plasma concentration of reduced glutathione reflects hepatocellular damage associated with endotoxin hepatitis. The partial reversal of the damage by ulinastatin is consistent with the proposal that the activation of polymorphonuclear leukocytes is involved in endotoxin hepatitis.

Animals↗
PubMed1993

Late development of cholangiocarcinoma after the treatment of hepatolithiasis.

Although the association of cholangiocarcinoma with intrahepatic calculi (hepatolithiasis) is well recognized, the late development of cholangiocarcinoma after the treatment of hepatolithiasis has not been reported in detail. Of 109 consecutive patients with hepatolithiasis treated during 19 years, eight patients had cholangiocarcinoma, seven of whom had cholangiocarcinoma two to 14 years, with a mean of eight years, after the treatment of hepatolithiasis. Absence of cholangiocarcinoma was confirmed when stones were removed at the time of the initial treatment. The mean age was 56 years, with a female to male ratio of 2:5. At the time of detecting cholangiocarcinoma, three patients had no gallstones and four had gallstones at the corresponding site to the carcinoma. Cystic dilatation of the intrahepatic bile duct was often observed on the direct cholangiogram. The biles were all infected mainly with Escherichia coli and Klebsiella species. Thus, bile stasis and bacteria infection seems to be the important causative factor, causing cholangiocarcinoma rather than the calculi itself. Because the symptoms only mimic those of cholangitis, the possible presence of cholangiocarcinoma should be considered even after the treatment of hepatolithiasis for early detection and curative resection.

Adenoma, Bile Duct↗
PubMed1992

A repetitive DNA element, associated with telomeric sequences in Drosophila melanogaster, contains open reading frames.

He-T sequences are a complex repetitive family of DNA sequences in Drosophila that are associated with telomeric regions, pericentromeric heterochromatin, and the Y chromosome. A component of the He-T family containing open reading frames (ORFs) is described. These ORF-containing elements within the He-T family are designated T-elements, since hybridization in situ with the polytene salivary gland chromosomes results in detectable signal exclusively at the chromosome tips. One T-element that has been sequenced includes ORFs of 1,428 and 1,614 bp. The ORFs are overlapping but one nucleotide out of frame with respect to each other. The longer ORF contains cysteine-histidine motifs strongly resembling nucleic acid binding domains of gag-like proteins, and the overall organization of the T-element ORFs is reminiscent of LINE elements. The T-elements are transcribed and appear to be conserved in Drosophila species related to D. melanogaster. The results suggest that T-elements may play a role in the structure and/or function of telomeres.

Amino Acid Sequence↗
PubMed1992

Promoting effects of both dietary cholesterol and cholestyramine on pancreatic carcinogenesis initiated by N-nitrosobis(2-oxopropyl)amine in Syrian golden hamsters.

The effects of dietary cholesterol and cholestyramine on pancreatic carcinogenesis initiated with N-nitrosobis(2-oxopropyl)amine (BOP) were investigated in 120 female Syrian golden hamsters. BOP (70 mg/kg body weight) was injected s.c. once at the beginning of the experiment. Starting 2 weeks later, the animals were then maintained on basal diet or diets containing either 0.5% cholesterol or 1% cholestyramine for a further 16 weeks. All surviving hamsters were killed at week 18, and the pancreas tissues examined histologically. The incidences of pancreatic carcinomas in hamsters fed cholesterol and the cholestyramine supplement were 40.0 and 30.0% respectively; in both cases significantly higher than the 6.9% incidence in the basal diet group. Cholesterol contents of the serum, pancreas and liver were significantly increased by cholesterol feeding and significantly decreased by the cholestyramine diet. The cholesterol diet also significantly increased pancreatic protein and DNA contents, and the concentration of total bile acids and the level of lithocholic acid in gallbladder bile. The cholestyramine diet significantly increased total pancreatic DNA and protein contents, and pancreatic weight. The results thus indicated that both dietary cholesterol and cholestyramine can enhance BOP-initiated pancreatic carcinogenesis in hamsters.

Adenocarcinoma↗
PubMed1992

Sequence analysis of active mariner elements in natural populations of Drosophila simulans.

Active and inactive mariner elements from natural and laboratory populations of Drosophila simulans were isolated and sequenced in order to assess their nucleotide variability and to compare them with previously isolated mariner elements from the sibling species Drosophila mauritiana and Drosophila sechellia. The active elements of D. simulans are very similar among themselves (average 99.7% nucleotide identity), suggesting that the level of mariner expression in different natural populations is largely determined by position effects, dosage effects and perhaps other factors. Furthermore, the D. simulans elements exhibit nucleotide identities of 98% or greater when compared with mariner elements from the sibling species. Parsimony analysis of mariner elements places active elements from the three species into separate groups and suggests that D. simulans is the species from which mariner elements in D. mauritiana and D. sechellia are most likely derived. This result strongly suggests that the ancestral form of mariner among these species was an active element. The two inactive mariner elements sequenced from D. simulans are very similar to the inactive peach element from D. mauritiana. The similarity may result from introgression between D. simulans and D. mauritiana or from selective constraints imposed by regulatory effects of inactive elements.

Animals↗
PubMed1992

Spontaneous mutations affecting glycerol-3-phosphate dehydrogenase enzyme activity in Drosophila melanogaster.

Significant genetic variance in glycerol-3-phosphate dehydrogenase (GPDH) activity was observed between chromosome lines of Drosophila melanogaster that had each accumulated spontaneous mutations for approximately 300 generations. No restriction map variation was found in a 26-kb region surrounding the entire Gpdh gene. The restriction analysis used is capable of detecting insertions/deletions larger than 0.05 kb. The survey would also detect chromosomal recombinations that include the entire Gpdh coding region. Therefore, if the spontaneous mutations that affected the enzyme activity are located inside the Gpdh gene region, then they are base pair substitutions or structural changes that are smaller than the limit in resolution described above.

Alcohol Dehydrogenase↗
PubMed1992

[Construction of a multiple mood scale].

A self-report instrument to measure multiple mood states was constructed. Six hundred and forty-eight Japanese affect adjectives were collected and divided into two lists. Japanese undergraduates totaling 1,254 rated each adjective in the list on a 4-point intensity scale to assess their momentary mood states. Factor analyses revealed 131 items with high loading on extracted major factors. The new list of these 131 items was rated three times by undergraduates totaling 1,768 and was factor analysed. Throughout the factor analyses, eight factors emerged with consistent reliability. Finally, 80 items highly loaded on these factors were selected to construct eight 10-item mood scales. These scales were called Depression (Anxiety), Hostility, Boredom, Liveliness, Well Being, Friendliness, Concentration and Startle. The scales were shown to be internally consistent. A comparison of these scales with the English mood scales was presented.

Adolescent↗
PubMed1992

[A case of hydropneumothorax].

A 19-year-old girl was admitted because of fever, cough and suddenly occurred chest pain. One month earlier she had experienced a fever and cough, then she had felt sudden chest pain 2 weeks prior to the admission. A chest X-ray showed left pneumothorax and massive pleural effusion. A diagnosis of hydropneumothorax was made. In spite of the chest tube drainage, reexpansion of the lung was unsatisfactory. Thoracotomy and decortication of the lung resulted in good reexpansion. Histological finding revealed pleuritis due to bacterial peribronchial infection, which resulted in hydropneumothorax, namely an abscess ruptured to the pleural cavity.

Adult↗
PubMed1991

Fibronectin: a possible factor promoting cholesterol monohydrate crystallization in bile.

To examine the hypothesis that fibronectin physiologically present in bile might be a possible nucleating factor, the concentrations of fibronectin in gallbladder bile were determined and its induced effect on nucleation time and on the form of vesicle were examined in bile-model and human gallbladder bile. The gallbladder bile samples taken from patients with cholesterol gallstone had a significantly higher concentration of fibronectin and the faster nucleation time than the control. However, no significant correlation was found between nucleation time and endogenous fibronectin concentration. The addition of 0.5, 1.2, 10 micrograms/ml of fibronectin into two kinds of bile-model significantly shortened the nucleation time in a dose-related manner. Nucleation time was significantly shortened by the addition of 1 microgram/ml exogenous fibronectin into abnormal bile while such an effect was absent in the control. The addition of fibronectin increased the size of vesicles observed by the electron microscope. The results suggest that fibronectin physiologically present in bile may be one of the possible nucleating factors.

Analysis of Variance↗
PubMed1991

Establishment and characterization of monoclonal antibodies against Chuzan virus K-47.

We established sixteen mouse monoclonal antibodies reactive to Chuzan virus K-47 strain using P3-X63-Ag8-U1 cells as fusion partner cells. Among them, CG53/2/4 recognized a 100K structural protein of the virus. The 100K antigen lost it's antigenicity for CG53/2/4 after mild periodate oxidation treatment, suggesting that the 100K viral antigen is a glycoprotein. In addition, CG53/2/4 neutralized the viral infectivity. This indicates that the 100K glycoprotein is essential for the infection of the virus. The other monoclonal antibodies reacted with a 41K antigen of the virus. Especially CG1/1 showed the highest reactivity to the virus. Forward step sandwich assay using CG1/1 and biotinylated CG53/2/4 could detect the virus at 10TCID50/ml. Therefore, these monoclonal antibodies can eventually predict the virus infection to the animals before their sideration.

Animals↗
PubMed1991

He-T family DNA sequences in the Y chromosome of Drosophila melanogaster share homology with the X-linked stellate genes.

The genome of Drosophila melanogaster contains a class of repetitive DNA sequences called the He-T family, which is unusual in being confined to telomeric and heterochromatic regions. The specific He-T fragment designated Dm665 was cloned in yeast by selection for an autonomously replicating sequence (ARS). Dm665 contains a restriction fragment length polymorphism (RFLP) that is specific to males and thus derives from the Y chromosome. Deletion mapping using X-Y translocations indicates that sequences homologous to Dm665 occur in at least one major cluster in each arm of the Y chromosome. Among 20 yeast artificial chromosome (YAC) clones containing Drosophila sequences homologous with Dm665, four clones derive from defined regions of the long arm of the Y and two from the short arm. The sequence of Dm665 is 2443 bp long, consists of 59% A + T, and contains no significant open reading frames or direct or inverted repeats. However, Dm665 contains a region of 650 bp that shares homology with portions of the X-linked locus Stellate.

Animals↗
PubMed1991

A method for detecting effect of beneficial mutations in natural populations of Drosophila melanogaster.

An experimental method is proposed for detecting the effects of positive natural selection on DNA polymorphisms. Since beneficial mutations are expected to increase in frequency faster than neutral mutations, variants which have reached high frequencies in a relatively short period could be linked to some beneficial mutation. D. melanogaster has a cosmopolitan polymorphic inversion -In(2L)t- whose age in some local populations has been estimated. Setting the age of In(2L)t as the upper limit for the age of variants, we searched for variants whose frequencies were possibly influenced by positive natural selection. We detected a single candidate whose frequency and distribution met the requirements imposed by our method.

Alleles↗
PubMed1991

Introduction of the transposable element mariner into the germline of Drosophila melanogaster.

A chimeric white gene (wpch) and other constructs containing the transposable element mariner from Drosophila mauritiana were introduced into the germline of Drosophila melanogaster using transformation mediated by the P element. In the absence of other mariner elements, the wpch allele is genetically stable in both germ cells and somatic cells, indicating that the peach element (i.e., the particular copy of mariner inserted in the wpch allele) is inactive. However, in the presence of the active element Mos1, the wpch allele reverts, owing to excision of the peach element, yielding eye-color mosaics and a high rate of germline reversion. In strains containing Mos1 virtually every fly is an eye-color mosaic, and the rate of wpch germline reversion ranges from 10 to 25%, depending on temperature. The overall rates of mariner excision and transposition are approximately sixfold greater than the rates in comparable strains of Drosophila simulans. The activity of the Mos1 element is markedly affected by position effects at the site of Mos1 insertion. In low level mosiac lines, dosage effects of Mos1 are apparent in the heavier level of eye-color mosaicism in Mos1 homozygotes than in heterozygotes. However, saturation occurs in high level mosaic lines, and then dosage effects are not observed. A pBluescribe M13+ plasmid containing Mos1 was injected into the pole plasm of D. melanogaster embryos, and the Mos1 element spontaneously integrated into the germline at high efficiency. These transformed strains of D. melanogaster presently contain numerous copies of mariner and may be useful in transposon tagging and other applications.

Alleles↗
PubMed1991

Establishment and characterization of monoclonal antibodies against bovine ephemeral fever virus.

We established fourteen monoclonal antibodies (MAbs) reactive to bovine ephemeral fever virus YHL strain, and characterized six representatives including three IgG1s (YG3/4, YG5/8, and YG6/7) and three IgMs (YM4/9, YM2/6, and YM6/8). Among them, YG3/4 and YM4/9 gave especially strong reactivities to the virus. YM4/9 reacted specifically with a 43K antigen of the virus, corresponding to the matrix protein 1. The other MAbs reacted most strongly with the 43K antigen, but also reacted with unknown 23K and 21K antigens. By a simultaneous two-site method using YM4/9 and YG3/4, it was possible to detect 10(4.10)TCID50/ml of the virus, in the presence of serum.

Animals↗