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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 793 records · Page 44Linked to original sources
PubMed1994

Primary structure and transcription of genes encoding B870 and photosynthetic reaction center apoproteins from Rubrivivax gelatinosus.

We determined the nucleotide sequence of the puf operon of Rubrivivax gelatinosus (formerly called Rhodocyclus gelatinosus), a photosynthetic bacterium belonging to the beta subclass of purple bacteria (proteobacteria). The operon contains two unknown open reading frames (ORFs) in addition to five photosynthetic genes which have been reported in species belonging to the alpha subclass. These genes include pufB, -A, -L, -M, and -C coding for the beta and alpha subunits of the B870 light-harvesting protein and for the L, M, and cytochrome subunits of the reaction center complex, respectively. One (ORF1) of the two unknown ORFs locates immediately upstream of pufB, while the other (ORF2) locates between pufB and pufA. The deduced product of ORF1 is a small basic protein composed of 41 amino acids that did not show homology with any other proteins reported to date. The deduced product of ORF2 was composed of 74 amino acids having a hydrophobic region able to span the membrane and showed homology with the beta subunit of B870. The deduced amino acid sequence of the cytochrome subunit of the reaction center of R. gelatinosus had significant deletions in the possible attachment site to the M subunit compared with that of Rhodopseudomonas viridis. This is consistent with the facilitated dissociation of this subunit observed with detergent treatment in R. gelatinosus. Analysis of RNA from R. gelatinosus showed that the puf operon of this bacterium has two transcripts; the major one is 1 kilobase in length and the minor one is 4 kilobase in length. These two transcripts have the same 5'-end, and their stoichiometry appeared to be controlled by a putative hairpin structure between pufA and pufL.

Amino Acid Sequence↗
PubMed1994

Establishment of human oral-cancer cell lines (KOSC-2 and -3) carrying p53 and c-myc abnormalities by geneticin treatment.

Two cultured cell lines derived from human squamous-cell carcinomas were established through xenografted tumors in nude mice by "Geneticin" treatment, which allows to eliminate contaminated mouse fibroblasts and obtain enriched tumor cells at the early stage of cultivation. Line KOSC-2 and KOSC-3 were each derived from a squamous-cell carcinoma of the oral floor and of the lower gingiva, respectively. Both lines grew in a cobblestone pattern, demonstrating their epithelial heritage. Giemsa-banding patterns by chromosome analysis confirmed that both lines are of human origin. Molecular analysis of cancer-related genes, including the Ha-ras, c-myc and p53 genes, was performed. KOSC-3 cells showed co-over-expression of p53 and c-myc mRNA, in addition to p53 point mutation at codon 248 with transition from CGG to TGG. However, loss of heterozygosity (LOH) on chromosome 17 was detected in both lines by Southern blotting. These cell lines provide a model for elucidating the mechanism involving p53 inactivation and c-myc-gene over-expression.

Aged↗
PubMed1994

An isolated, complete resection of the caudate lobe, including the paracaval portion, for hepatocellular carcinoma.

An isolated resection of the entire caudate lobe, including the paracaval portion, was performed in a 68-year-old man with hepatocellular carcinoma complicated by chronic hepatitis. Precise resection of the paracaval portion, which surrounds the right side of the inferior vena cava, is difficult because of its deep location and the lack of superficial landmarks indicating its margins. Using a counterstaining technique to define the right margin and the transhepatic anterior approach to access the ventral border, the paracaval portion, with the spigelian lobe and the caudate process, was completely resected without sacrificing the other part of the liver. The whole procedure was performed without blood transfusion, and the postoperative course of the patient was uneventful. This procedure would add a new option for surgical management of hepatic malignancies originating in the caudate lobe of the compromised liver.

Aged↗
PubMed1994

Multicystic aneurysmal dilatation of bilateral coronary artery fistula.

Bilateral coronary artery fistula constitutes an uncommon subgroup of coronary artery fistulas that may have a distinct embryologic origin. Coronary artery fistulas usually show a tortuous arrangement upon coronary angiography, but aneurysmal dilatation is rare. We report here an extremely rare case of coronary artery fistula originating from both coronary arteries, which showed multicystic aneurysmal dilatation.

Aged↗
PubMed1994

Detection of antibody IgG to HIV-1 in urine by ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant p24 as antigen for diagnosis of HIV-1 infection.

Anti-HIV-1 IgG in urine was detected by an ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant p24 gag protein (p24) of HIV-1 as antigen and beta-D-galactosidase from Escherichia coli as label. Anti-HIV-1 IgG in urine was reacted simultaneously with 2,4-dinitrophenyl-bovine serum albumin-recombinant p24 conjugate and recombinant p24-beta-D-galactosidase conjugate. The complex formed, consisting of the three components, was trapped onto polystyrene balls coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine, and transferred to polystyrene balls coated with affinity-purified (anti-human IgG gamma-chain) IgG. Bound beta-D-galactosidase activity was assayed by fluorometry. This assay was at least 3,000-fold more sensitive than conventional methods. The lowest signal among 49 asymptomatic carriers was 3.1-fold higher than the highest nonspecific signal among 100 seronegative subjects. The sensitivity and specificity were both 100%. The positivity could be confirmed by preincubation of urine samples with excess of the antigen. Thus, this assay would be a powerful tool for detecting IgG antibody to HIV-1 in urine.

Adolescent↗
PubMed1994

Diagnosis of HIV-1 infection by detection of antibody IgG to HIV-1 in urine with ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant proteins as antigens.

Anti-HIV-1 IgG in urine was detected by an ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant reverse transcriptase (RT), p17 and p24 as antigens, and beta-D-galactosidase from Escherichia coli as label. Anti-HIV-1 IgG in urine was reacted simultaneously with 2,4-dinitrophenyl-bovine serum albumin-recombinant protein conjugate and recombinant protein-beta-D-galactosidase conjugate. The immune complex formed, consisting of the three components, was trapped onto polystyrene balls coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG. After washing, the immune complex was eluted from the polystyrene balls with excess of epsilon N-2,4-dinitrophenyl-L-lysine and transferred to clean polystyrene balls coated with affinity-purified (anti-human IgG gamma-chain) IgG. Finally, the enzyme activity bound to the last solid phase was assayed by fluorometry. Using recombinant RT as antigen, the sensitivity and specificity for 83 seropositives and 100 seronegatives were both 100%, and the lowest signal for 60 asymptomatic carriers was 8.2-fold higher than the highest signal for the seronegatives. The positivity with recombinant RT as antigen could be confirmed by using recombinant p17 and p24 as antigens. The sensitivity could be improved by a longer assay of bound beta-D-galactosidase activity by using concentrated urine samples and by the combined use of recombinant RT, p17, and p24. Thus, reliable diagnosis of HIV-1 infection was possible for asymptomatic carriers.

Acquired Immunodeficiency Syndrome↗
PubMed1994

In vivo antiviral effects of mismatched double-stranded RNA on duck hepatitis B virus.

The antiviral activity and ability of mismatched double-stranded RNA (m-dsRNA), r(I)n.r(C12-U)n, to induce interferon (IFN) were evaluated in ducks chronically infected with duck hepatitis B virus (DHBV). When m-dsRNA was administered intravenously at a single dose of 5 mg/kg, serum DHBV DNA concentrations decreased significantly for 3 days (P < 0.002). However, the DHBV DNA concentrations returned to the pretreatment levels 4 days after treatment. Inhibition of DHBV DNA replication in the liver was also observed 2 days after treatment. Serum IFN activity peaked 3 hours after administration of m-dsRNA, then rapidly declined. 2'-5' Oligo-adenylate synthetase (2'-5'AS) activity increased gradually after treatment and remained elevated for at least 48 hours. In ducks receiving m-dsRNA once daily for 7 consecutive days, serum DHBV DNA concentrations on the last day of treatment were decreased by 76 +/- 12% (P < 0.05) in ducks that received 0.2 mg of m-dsRNA per kg and by 65 +/- 12% (P < 0.05) in ducks that received 1 mg of m-dsRNA per kg. This decrease persisted for at least 2 weeks after the cessation of treatment in all ducks. These results suggest that m-dsRNA effectively inhibits DHBV replication in vivo, and that IFN induction and stimulation of 2'-5'AS activity contribute to the inhibition of DHBV replication by m-dsRNA.

Animals↗
PubMed1994

Suppression of experimental allergic encephalomyelitis in Lewis rats by administration of gangliosides.

Gangliosides (GA) are known to suppress T cell responses to mitogens and alloantigens. GA treatment (more than 50 mg/kg/rat subcutaneously every 12 hr) significantly suppressed clinical signs and histologic lesions of both actively induced and cell-transferred experimental allergic encephalomyelitis (EAE) in Lewis rats in a dose-dependent manner: P < 0.01, in actively induced EAE; P < 0.001 (100 mg/kg) or P < 0.005 (50 mg/kg), in cell-transferred EAE. Lymph node cells from guinea pig myelin basic protein (GPMBP)-sensitized rats were stimulated in vitro with the specific sensitizing antigen, GPMBP, or with Con A. Purified bovine brain GA significantly suppressed GPMBP-induced proliferation in a dose-dependent manner (P < 0.01). GA treatment during sensitization phase (from Day -5 to Day 4) did not suppress actively induced EAE. There were no significant differences in T cell subsets of peripheral blood or spleen cells between GA-treated rats and controls by flow cytometry analysis. Taken together, these findings indicate that GA primarily act on the immune effector phase of EAE.

Animals↗
PubMed1994

Prolactin, growth hormone, and luteinizing hormone-beta subunit gene expression in the cephalic and caudal lobes of the anterior pituitary gland during embryogenesis and different reproductive stages in the chicken.

Messenger RNA (mRNA) levels of prolactin (PRL), growth hormone (GH), and luteinizing hormone (LH)-beta subunit in the cephalic and caudal lobes of the anterior pituitary gland of the chicken during embryonic development and different reproductive stages were determined by Northern blot analysis and are related to hormone levels in plasma and each lobe. Steady-state levels of 1.4-kb transcript of PRL of the cephalic and caudal lobes increased on Days 18 and 20 of incubation, respectively. The levels were greater in the cephalic lobe than in the caudal lobe on Days 18 and 20 of incubation. Levels of PRL in each lobe show similar changes to those of mRNA levels. GH mRNA levels of both lobes started to increase on Day 16 of incubation but the levels were higher in the caudal lobe than in the cephalic lobe on Days 16-20 of incubation. Levels of GH in the cephalic lobe increased discontinuously, while those in the caudal lobe increased continuously on days of incubation. LH-beta mRNA was not detected in embryos. Levels of PRL mRNA increased approximately 18-, 20-, and 3-fold in hens at 1 and 3 weeks of egg incubation and brooding stages in the hen, relative to prelaying, respectively. These levels were higher in the cephalic lobe than in the caudal lobe at all stages except for prelaying stages. Levels of PRL in each lobe displayed essentially similar changes to the mRNA levels. GH mRNA levels did not significantly vary during the cycle but were higher in the caudal lobe than in the cephalic lobe. There was no difference in LH-beta mRNA levels between the two lobes but the levels were higher at prelaying and laying stages than at incubation and brooding stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Bioabsorbable osteosynthetic implants of ultra high strength poly-L-lactide. A clinical study.

We have developed reasonably strong but bioabsorbable osteosynthetic screws, pins and nails made of ultra high strength poly-L-lactide (PLLA) and evaluated their use in 143 patients. The PLLA implants have the highest strength among those reported to date. They lose about 10% of their initial strength within 8 weeks, about 40% within 4 weeks and nearly 100% within 20 weeks in vivo. The patients were aged from 9 to 78 years, and the follow up was from 2 to 6 years. The implants were used for fixation of bone grafts in 84 patients, peri- and intra-articular fractures in 49, after osteotomy in 8, and in 2 others. Bony union was not achieved in only one case. In the early stages of the study, breakage of screws occurred in 12 cases (8%), mostly because of an inappropriate size of tap; these problems have not occurred after improvement of the tapping system. There were no cases with abnormal blood tests, infection or foreign body reaction.

Adolescent↗
PubMed1994

A visual data analysis system for the medical image processing.

We developed a visual data analysis system that can easily manage a large volume of medical imaging data. This system can analyze sets of imaging data using general image processing methods, so that various kinds of medical imaging data such as ECG charts, X ray image films, and MRI images, can be processed. The system has a graphical user interface (GUI). A physician who is novice at the system can manipulate the imaging data intuitively by pull down menus, pop up menus and buttons within the window system. The system can run on a standard UNIX workstation which is faster and more powerful than most personal computers. The system needs an X window system/Motif and C compiler. These are standard system programs already available on most UNIX workstations. The source code of the system can be retrieved from our anonymous ftp site via Internet.

Computer Graphics↗
PubMed1994

Direct lymphatic drainage from the esophagus into the thoracic duct.

The lymphatic vessels from around the esophagus which drain into the thoracic duct were identified macroscopically and histologically in 106 cadavers. Direct lymphatic drainage to the duct was macroscopically demonstrated by 84 vessels in 46 cases (43.4%). In 23 cases (19.8%), large collecting vessels arose from the thoracic esophagus and opened directly into the duct. In most of these cases (15/23) these lymphatic connections were found at the levels of the 1st-3rd or 6th-8th thoracic vertebrae. Histologic study revealed that two vessels originated from the fine lymphatic plexus in the esophageal adventita, which showed monocytic infiltration. In 11 of the 23 cases, an intercalated node was found along the thoracic duct. The results suggest that lymph drains rapidly into the systemic circulation via the thoracic duct. In view of the clinical applications in esophageal carcinoma, previous accounts of the extramural esophageal lymphatics concerned in direct drainage are discussed.

Aged↗
PubMed1994

Noninvasive evaluation of the influence of aortic wave reflection on left ventricular ejection during auxotonic contraction.

To develop a noninvasive method for evaluating the influence of aortic wave reflection on left ventricular ejection, the carotid pulse wave and the pulsed Doppler wave in the left ventricular outflow tract were evaluated in 35 patients. Agreement between the pulsed Doppler waveform and the aortic flow velocity contour (obtained invasively) was verified by Fourier analysis. The carotid augmentation index was used to determine the magnitude of the aortic pressure wave reflection. A Doppler index named "DR1/3" was defined as the ratio of deceleration at the first one-third in the deceleration phase to the peak flow velocity of the pulsed Doppler. This index was validated by close correlation with the carotid augmentation index (n = 48, r = 0.70, P < 0.01). Both nitrates and nifedipine induced a significant decrease in DR1/3 (indicating an increase in left ventricular ejection flow) in relation to a reduction of the reflected pressure wave. The new noninvasive index, DR1/3, is useful in evaluating the influence of aortic wave reflection as part of the left ventricular afterload and in assessing the benefit of treatment aimed at reducing wave reflection.

Aorta↗
PubMed1994

Asymptomatic vesicoureteral reflux in children.

Between 1973 and 1992, a routine voiding cystourethrography screening was performed in all children attending our urological clinic. A total of 1023 children were diagnosed as cases of primary vesicoureteral reflux; 166 (210 renal units) of them were asymptomatic and were studied retrospectively. Ninety-one patients presented with enuresis, 39 with hypospadias, 14 with undescended testis, 8 with asymptomatic proteinuria and 14 had other manifestations such as intersexuality, inguinoscrotal swelling, abnormal external genitalia, etc. We documented high-grade reflux (IV-V) in 16.2% and renal scarring in 16.7% of the 210 renal units. None of the children showed features of urinary tract infection (UTI) or had a definite history in the past, but 23.5% of the 166 cases developed UTI during their follow-up period. Spontaneous resolution of reflux was observed in 52.7% of the 150 renal units and progression of renal scarring in 20% during follow-up. Antireflux operation was performed in 15 cases (26 renal units). In 9 children (5.4%) we found gross renal damage which progressed in two cases to end-stage renal disease followed by renal transplantation. A small kidney was noted in 5 patients and hypertension in two. It is concluded that the natural history of asymptomatic reflux is almost the same as in symptomatic reflux. Thus, routine voiding cystourethrography is suggested in all children attending a urological clinic in order to detect reflux as early as possible.

Adolescent↗