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Biomedical subjects

K Nishikawa

Publications and source records attributed to K Nishikawa.

At least 289 records · Page 16Linked to original sources

[An enzyme-linked immunosorbent assay determining anti-principal neutralizing determinant antibodies using synthetic peptides deduced from cDNA sequences of HIV-1 V3 loop domain].

The V3 domain, one of the hypervariable regions of gp 120 in HIV-1 possesses principal type-specific neutralizing determinant (PND). The V3 domain has the epitopes for class I major histocompatibility antigens of cytotoxic-T lymphocyte and helper-T-lymphocyte recognition sites, and also has major determinants for cell tropism towards macrophage, microglia, and human brain-derived fibroblast. Therefore, establishment for the assay of anti-PND antibodies in patients with HIV-1 infection appears to be important for the estimation on developing AIDS in these patients. We here describe a simple enzyme-linked immunosorbent assay (ELISA) for the measurement of anti-PND antibodies found in Japanese hemophiliacs. ELISA was performed using synthetic peptides, each 15 amino acid residues deduced from cDNA sequences of seven HIV-1 V3 domain mutants, which include 5 North-American and European strains (IIIB, MN, RF, SC, and WMJ-2) and 2 African strains (Af1. Con and Af2, Con). The specific antibody binding to each peptide was determined after subtraction of the non-specific binding from the total. In 49 control sera from healthy individuals with HIV-1 antibody negative, the absorbance (M +/- 1SD) at 405 nm was -0.002 +/- 0.064. Then, the cut off value was determined to be M + 4SD. In 48 hemophiliac sera with HIV-1 antibody negative, the absorbance was uniformly less than the cut off value. However, among 44 hemophiliac sera with HIV-1 antibody positive, the anti-PND antibodies were detected in the following frequencies; 2 for IIIB, 20 for MN, 1 for RF, 1 for Af1. Con, and 5 for Af2. Con.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS Serodiagnosis↗

Effects of delapril on stroke, kidney dysfunction and cardiac hypertrophy in stroke-prone spontaneously hypertensive rats.

This study was performed to investigate the beneficial effects of prolonged treatment with an angiotensin converting enzyme (ACE) inhibitor, delapril, on the appearance of symptoms of hypertensive cardiovascular disease in stroke-prone spontaneously hypertensive rats (SHRSP). Cardiovascular disease symptoms: stroke, kidney dysfunction and cardiac hypertrophy, were evaluated by monitoring the incidence of stroke signs, urinary excretion of protein and the heart weight, respectively. The SHRSP that were kept under salt-loaded conditions (1% NaCl drinking solution) from six weeks of age developed severe hypertension, showed an increased incidence of stroke signs and increased urinary excretion of protein. Long-term treatment with delapril (10mg/kg/day, p.o. for four weeks) decreased the blood pressure and completely inhibited the incidence of stroke signs and the increase in urinary excretion of protein. In SHRSP that were kept under normal conditions (without 1% NaCl drinking solution), long term treatment with delapril at the same dose decreased the heart weight and, after five weeks of treatment, left ventricular weight was decreased significantly and the wall/lumen ratio of small coronary arterioles and the thickness of the left ventricular wall were decreased slightly. These results indicate that delapril can prevent the development of symptoms of hypertensive cardiovascular diseases: stroke, kidney dysfunction and cardiac hypertrophy, with antihypertensive activity in SHRSP.

Angiotensin-Converting Enzyme Inhibitors↗

Embryonic fibronectin isoforms are synthesized in crescents in experimental autoimmune glomerulonephritis.

Crescents are a severe and stereotyped glomerular response to injury that occur in several forms of glomerulonephritis that progress to renal failure. The key pathogenetic step that leads to glomerular scarring in unknown, but fibronectin (FN), the clotting system, macrophages, and proliferating parietal epithelial cells are known to participate. This study was designed to determine whether FN is synthesized locally, and in what molecular isoform, and whether cytokines known to promote FN synthesis are present in the crescent. Rats immunized with bovine glomerular basement membrane develop cellular crescents by 14 days and fibrous crescents and glomerulosclerosis by 35 days. In situ hybridization was performed with oligonucleotides specific for sequences common to all FN isoforms (total FN) or sequences specific for the alternatively spliced segments (EIIIA, EIIIB, and V). Throughout the time period (14, 21, and 35 days) all crescents and glomerular tufts contained cells with strong ISH signals for total and V+ mRNA, with the strongest signals present in large cellular crescents at day 21. In contrast, EIIIA+ and EIIIB+ mRNAs showed maximal abundance within sclerosing crescents at 35 days. Protein deposition of EIIIA+, EIIIB+, and V+ FN isoforms was confirmed by immunofluorescence with segment-specific FN antibodies. Transforming growth factor-beta and interleukin-1 beta, both known to promote FN synthesis, were found in cellular crescents (days 14 and 21) and were still present, but greatly diminished, in the sclerotic phase (day 35). In summary, EIIIA-, EIIIB-, and V+ FN mRNA plasma isoforms predominate in cellular crescents, whereas in the fibrosing stage, mainly the oncofetal EIIIA+, EIIIB+, and V+ isoforms are synthesized and accumulate.

Alternative Splicing↗

[Questionnaire survey on "The guidelines on diagnosis and treatment of asthma" edited by the Japanese Society of Allergology (1993)].

A questionnaire on the evaluation of "The Guidelines on Diagnosis and Management of Asthma" edited by the Japanese Society of Allergology in 1993 was sent to 586 physicians consisting of specialists authorized by the Japanese Society of Allergology and the board members of this Society, who treated patients with bronchial asthma. Of total 306 (52.2%) who responded, 177 (57.8%) answered the questions on adult asthma only, 65 (21.2%) on childhood asthma only and 52 (17.9%) on both adult and childhood asthma. In total, we had 229 respondents on adult asthma and 117 on childhood asthma. As a result, on drug therapy for chronic asthma, it was pointed out that the use of oral anti-allergics, oral steroids and inhaled beta-stimulants was excessive whereas the use of DSCG, inhaled steroids and long acting theophylline was slightly insufficient in both adults and children. On the management of acute episodes, the excessive use of beta-stimulants (inhaled, oral and injections) and the lack of the use of parenteral steroids and oxygen inhalation were pointed out in adults. The lack of oxygen inhalation also got a higher percent in children. Nevertheless, the guidelines were found to be highly regarded as a whole: "Very good" was 6.1% in adults (6.8% in children). "Appropriate" 38.0% (33.3%), "Almost appropriate" 52.0% (52.1%) and "Inappropriate" 3.9% (3.4%).

Adult↗

[A case of successful surgical retrieval of the intracoronary interlocked Palmaz-Schatz stent].

We presented a case of a 48-year-old male with failed delivery of the Palmaz-Schatz stent, who subsequently required CABG with successful retrieval of the stent. The patient had presented recurrent angina, approximately one and a half year since the last PTCA to the LAD. Re-PTCA was performed, but resulted in a severe local dissection. The stent implantation was tried, but was inadvertently dropped in the vessel. Since the patient was hemodynamically stable, we tried to remove the stent with Retriever endovascular snare, which ended up with interlocking the stent in the more proximal segment of the LAD and the snare itself was not removed. We, therefore, resort to the emergent operation, with successful retrieval of the snare device and the stent and carried on to the the bypass operation to the distal LAD without any complications. To our best knowledge, this is the first report in Japan for surgical retrieval of the Palmaz-Schatz stent, which was failed in delivery and interlocked in the vessel with retriever device.

Angina Pectoris↗

Role of angiotensin II in cerebrovascular and renal damage in deoxycorticosterone acetate-salt hypertensive rats.

OBJECTIVE AND DESIGN: To study the effects of blockade of the renin-angiotensin system on the development of hypertension and end-organ damage in hyporeninaemic deoxycorticosterone acetate (DOCA)-salt hypertensive rats, using an angiotensin II (Ang II) receptor antagonist (TCV-116) or an angiotensin converting enzyme (ACE) inhibitor (enalapril). METHODS: DOCA-salt hypertensive rats were produced by uninephrectomy, implantation with DOCA pellets and 1% NaCl loading. TCV-116 (0.1 or 1 mg/kg) or enalapril (10 mg/kg) was given orally once a day from 3 to 6 weeks after the operation. Body weight, blood pressure, plasma renin and creatinine, urinary protein and blood urea nitrogen were measured. After 3 weeks' treatment, oedema and omega 3-subtype benzodiazepine receptor binding in the brain were measured. RESULTS: Three weeks after the operation the blood pressure in the DOCA-salt hypertensive rats was approximately 200 mmHg, and the plasma renin concentration was lower than in sham-operated rats. However, after a further 3 weeks the renin concentration was slightly above the normal level, and this increase was accompanied by a decrease in body weight and increases in blood urea nitrogen, plasma creatinine, urinary protein and omega 3-subtype benzodiazepine receptor binding in the cerebral cortex, and by brain oedema. Treatment with TCV-116 or enalapril prevented renal damage and decrease in body weight with little effect on blood pressure. Enalapril prevented brain oedema and the increase in benzodiazepine binding in the brain cortex, and 1 mg/kg TCV-116 prevented them markedly. CONCLUSIONS: Although the hypertension in DOCA-salt hypertensive rats is independent of the renin-angiotensin system, the degree of cerebral and renal damage is associated with the activity of the renin-angiotensin system and has little relationship with the blood pressure level.

Administration, Oral↗

[Cardiopulmonary resuscitation with continuous veno-venous hemofiltration for intraoperative cardiac arrest owing to hypothermia--a case report].

A 77-year-old female was scheduled for an exploratory laparotomy under nitrous oxide-oxygen-neurolept anesthesia. At the time of admission to the operating room, the rectal temperature was 36.0 degrees C. From the beginning of operation, the body temperature dropped slowly despite constant efforts of warming with a blanket and warm intravenous fluids. At 5 hours and 15 minutes after the beginning of operation, she developed cardiac arrest due to hypothermia. At this time the rectal temperature was 31.8 degrees C. In spite of cardioversion and intravenous administration of epinephrine, we could not resuscitate her successfully. Immediately, rewarming was started with continuous veno-venos hemofiltration (CVVH). When the rectal temperature rose to 32.9 degrees C one hour after the rewarming, cardioversion was performed again and spontaneous heart beat was observed. As soon as the rectal temperature rose to 34.0 degrees C, CHF was stopped. Her consciousness recovered 2 hours and 10 minutes after cardiopulmonary resuscitation, we conclude that rewarming with CVVH can be an effective method of cardiopulmonary resuscitation in a patient suffering cardiac arrest due to hypothermia.

Aged↗

Purification and characterization of phosphoribulokinase from the cyanobacterium Synechococcus PCC7942.

Phosphoribulokinase (PRK) was purified to electrophoretic homogeneity from Synechococcus PCC7942 with high specific activity. Molecular masses of the native enzyme and its subunit were 178 and 42 kDa, respectively. Cys-17 and Cys-38 were conserved in the cyanobacterial PRK, but 18 amino acid residues between them were missing among the 40 residues found in higher plant PRKs.

Amino Acid Sequence↗

Relationship between Helicobacter pylori infection, atrophic gastritis and gastric carcinoma in a Japanese population.

AIM: To evaluate the possible relationship between Helicobacter pylori infection and gastric carcinoma, and its precursor lesion, intestinal metaplasia, in a Japanese population. SUBJECTS AND METHODS: H. pylori infection was identified by the presence of anti-H. pylori immunoglobulin (Ig)G. The frequency of H. pylori infection was compared in 109 patients with gastric carcinoma, the same number of patients with atrophic gastritis and asymptomatic controls matched for age, sex and place of birth. To study the relation between H. pylori and intestinal metaplasia, sera and gastric antral and corpus mucosal biopsies were obtained from 58 asymptomatic controls, 92 patients with chronic gastritis and 80 patients with peptic ulcer. RESULTS: The presence of IgG antibody to H. pylori was significantly more frequent in those with gastric carcinoma than in asymptomatic controls (87.2 versus 74.3%; odds ratio 2.4; 95% confidence interval 1.2-4.8). The positive rates of H. pylori IgG antibody were 80.7% in patients with atrophic gastritis. Mean serum gastrin and pepsinogen II levels in H. pylori-positive patients were higher than those in H. pylori-negative patients. Serum gastrin and pepsinogen I levels were significantly higher in controls than gastric carcinoma patients (P < 0.01 and P < 0.05, respectively). Serum pepsinogen I:II ratios were significantly lower in controls than in gastric carcinoma patients (P < 0.01). Intestinal metaplasia was strongly associated with H. pylori infection, and was only found in patients with IgG antibodies to H. pylori. CONCLUSIONS: These results suggest that H. pylori infection is associated with the development of gastric cancer by providing a suitable environment for carcinogenesis of the gastric mucosa, such as gastric atrophy and intestinal metaplasia.

Enzyme-Linked Immunosorbent Assay↗

Junctional and extrajunctional glutamate receptor channels in Drosophila embryos and larvae.

Glutamate receptor channels in Drosophila embryos and larvae were examined with the patch-clamp technique in various configurations. In the cell-attached mode, only one type of channel was observed in the extrajunctional region at any stages. The burst duration histogram was fit with three exponentials. The burst duration of long component lengthened with increasing glutamate concentration. In excised outside-out patches the unitary channel current was 7.1 pA at -60 mV and direction of current reversed at zero membrane potential. In contrast, junctional receptor channels had different properties. In the whole-cell configuration, spontaneous synaptic currents with steps on the falling phase were observed. The step amplitudes had two discrete values of 9.4 and 18.5 pA at -60 mV, due to openings of junctional glutamate receptor channels. Synaptic currents changed amplitudes linearly with the membrane potential in the negative potential range but nonlinearly above zero. With 1 mM glutamate in the bath, synaptic currents were no longer observed. Instead, there were single channel events with the current amplitude varying between 8 and 12 pA at -60 mV. Their long burst duration depended on glutamate concentration indicating that they are glutamate receptor channel events. The extrapolated reversal potential of these channel currents was around +12 mV. These junctional receptor channels were strictly localized at the junction. Our findings suggest that the channel conversion mechanism in Drosophila is different from that observed in vertebrates. Further close examination of other intermediate steps during neuromuscular junction formation is needed.

Animals↗

Objective and subjective assessments of Kodak Ektaspeed plus new dental X-ray film: a comparison with other conventional X-ray films.

A new dental X-ray film called EKTASPEED Plus has been released by the Eastman Kodak Company. Its sensitometric properties, inclusive of modulation transfer function (MTF) and Wiener spectrum (WS) and the visibility of radiographic details, were compared with those of other conventional dental X-ray films, EKTASPEED EP-22 (Eastman Kodak Co.) and Ultra-Speed DF-57 (Eastman Kodak Co.). The base plus fog density of EKTASPEED Plus was between those for EKTASPEED and Ultra-Speed. Relative speed of EKTASPEED Plus was slightly faster than EKTASPEED, and about two times faster than that of Ultra-Speed. The contrast of EKTASPEED plus was close to that of Ultra-Speed. Only minor differences existed between the film types studied when the sharpness and the granularity were compared. The MTF and WS also revealed no substantial differences between the films. Perceptibility testing showed minor differences between the three films, with EKTASPEED Plus consistently revealing more defects at lower exposures irrespective of whether a Burger's phantom or aluminum test block was used.

Evaluation Studies as Topic↗

Role of Helicobacter pylori in chronic gastritis: a prospective study.

We conducted a prospective study to evaluate the relationship between Helicobacter pylori infection and chronic gastritis in a Japanese population. H. pylori was found in 67% of patients positive for mononuclear cell (MN cell) infiltration and in 75.8% of patients positive for polymorphonuclear cell (PMN cell) infiltration, whereas H. pylori was found in 14.2% of patients without MN cell infiltration and in 33.2% of patients without PMN cell infiltration. The frequency of MN and PMN cell infiltration in H. pylori-positive patients was significantly higher than that in H. pylori-negative patients. The frequency of H. pylori infection did not differ in those with atrophic gastritis from those without, whereas the frequency of intestinal metaplasia became significantly higher in those with moderate and severe atrophy. There was no significant difference between serum pepsinogen I (PG I) levels in H. pylori-positive and -negative patients. However serum PG II levels were significantly increased in H. pylori-positive patients aged 40-69 years. The serum PG I-II ratio was significantly lower in H. pylori-positive patients aged 40-59 years. These results suggest that H. pylori infection in the gastric mucosa plays an important role in the pathogenesis of chronic and atrophic gastritis and in the development of intestinal metaplasia.

Adult↗

Higher-order structure of bovine mitochondrial tRNA(SerUGA): chemical modification and computer modeling.

On the basis of enzymatic probing and phylogenetic comparison, we have previously proposed that mammalian mitochondrial tRNA(sSer) (anticodon UGA) possess a slightly altered cloverleaf structure in which only one nucleotide exists between the acceptor stem and D stem (usually two nucleotides) and the anticodon stem consists of six base pairs (usually five base pairs) [Yokogawa et al. (1991) Nucleic Acids Res. 19, 6101-6105]. To ascertain whether such tRNA(sSer) can be folded into a normal L-shaped tertiary structure, the higher-order structure of bovine mitochondrial tRNA(SerUGA) was examined by chemical probing using dimethylsulfate and diethylpyrocarbonate, and on the basis of the results a tertiary structure model was obtained by computer modeling. It was found that a one-base-pair elongation in the anticodon stem was compensated for by multiple-base deletions in the D and extra loop regions of the tRNA(SerUGA), which resulted in preservation of an L-shaped tertiary structure similar to that of conventional tRNAs. By summarizing the findings, the general structural requirements of mitochondrial tRNAs necessary for their functioning in the mitochondrial translation system are considered.

Alkylating Agents↗

Characterization of basic fibroblast growth factor-mediated acceleration of axonal branching in cultured rat hippocampal neurons.

We analyzed in more detail the effect of basic fibroblast growth factor (bFGF) on morphogenesis of rat hippocampal neurons in dissociated cell culture. As a result, we found that bFGF selectively promoted the bifurcation and growth of axonal branches without affecting the elongation rate of primary axons. The dendritic outgrowth was rather inhibited by bFGF. These effects of bFGF resulted in increased complexity of axonal trees. The effect of bFGF was concentration dependent (0.1-10 ng/ml) and was abolished by the presence of anti-bFGF neutralizing antibody. The accelerated axonal branch formation in the presence of bFGF was restored to the basal rate following removal of bFGF, suggesting that the action of bFGF is reversible and that the continuous presence is required for bFGF to accelerate the branch formation. bFGF probably works as a progression signal rather than as a triggering signal. The bFGF-mediated acceleration of axonal branch formation was blocked by treatment with heparitinase and by tyrosine inhibitors, herbimycin A and lavendustin A, indicating the importance of heparan sulfate and tyrosine kinase in bFGF signal transduction. Treatment with a protein kinase C activator phorbol-12-myristate-13-acetate did not significantly affect the neurite branching, and the action of bFGF was not blocked by a protein kinase C inhibitor staurosporine. Protein kinase C is unlikely to play a role in branch formation. The novel action of bFGF as a regulator of axonal branching must be a particularly useful model for the study of neuritogenesis and synaptogenesis of brain neurons.

Alkaloids↗