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Biomedical subjects

K Kawata

Publications and source records attributed to K Kawata.

At least 55 records · Page 3Linked to original sources
PubMed1998

Upregulation of neural growth-associated protein and neural cell adhesion molecule in mouse olfactory epithelium and axons after unilateral removal of the olfactory bulb.

The expression of synaptosomal-associated protein (SNAP-25), neural growth-associated protein (GAP-43) and neural cell adhesion molecule (NCAM) were studied in mouse olfactory cells and axons for 2 weeks following unilateral bulbectomy. The olfactory cells and axons in the control olfactory epithelium were positive for SNAP-25 but levels decreased in the atrophic olfactory epithelium 3 days after bulbectomy. There was no expression of SNAP-25 in the olfactory epithelium on the bulbectomy side 7 days after bulbectomy, indicating that this protein may be a good marker for the degeneration of olfactory cells. The expression of NCAM was still found in the atrophic olfactory epithelium at 7 days after bulbectomy, while the expression of NCAM in the olfactory epithelium of the bulbectomy side was stronger than that on the control side at 14 days after bulbectomy. The expression of GAP-43 in the olfactory axonal bundles of the bulbectomy side at 3 and 4 days after bulbectomy was stronger than that on the control side. These results suggest that upregulation of NCAM may be related to the regeneration of the olfactory cells, with upregulation of GAP-43 probably playing a role in axonal regeneration after bulbectomy.

Animals↗
PubMed1998

Methylenetetrahydrofolate reductase and apolipoprotein E polymorphisms are independent risk factors for coronary heart disease in Japanese: a case-control study.

A missense variant of the C677T (Ala --> Val) polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) (the T allele) may increase levels of plasma homocysteine. Apolipoprotein E4 increases plasma LDL-cholesterol levels. Increased levels of homocysteine and LDL-cholesterol have been recognized as risk factors for coronary heart disease (CHD). To examine whether the polymorphisms in the MTHFR gene and the APOE gene are associated with CHD in the Japanese, we analyzed 214 CHD patients with an onset age before 65 and 310 apparently healthy persons. In the controls, significantly higher plasma concentrations of homocysteine were observed in the MTHFR TT genotype (15.1+/-6.0 mmol/l) compared with the CT genotype (11.2+/-1.9 mmol/l) and the CC genotype (10.5+/-3.3 mmol/l). The MTHFR TT genotype was significantly more frequent in the CHD patients (28.5%) compared with the control subjects (13.5%); the odds ratio was 2.54 (P < 0.00003). Subjects with the apo E4 allele were significantly more frequent in the CHD group (22.9%) than in the control group (10.0%); the odds ratio was 2.74 (P < 0.00004). Multivariate analysis showed that the TT genotype of MTHFR and the apoE4 allele are independent risk factors for CHD in the Japanese.

Adult↗
PubMed1998

[Evaluation of a PCR assay commercial kit for quantification of human immunodeficiency virus type-1 RNA].

We studied a basic evaluation of the reliability and usefulness of the test results to assess the validity of the kit "AMPLICOR HIV-1 Monitor" as a laboratory tool, by determining the reproducibility, linearity on dilution, possible effects of interference on the results, and correlation with the results obtained at outside facilities. Furthermore, we compared the HIV-1 RNA load between blood samples obtained from HIV-1 subtype B and E. The HIV-1 RNA load measurement was made according to the pre-determined methods of this kit, in blood samples obtained from HIV-positive outpatients. Simultaneous reproducibility was 23.08%-32.95% in C.V.% and linearity was maintained between 110 copies/ml and 2,184,277 copies/ml, demonstrating favorable performance of the kit. The institution correlation between two facilities were also favorable. Fluctuation of measurement by interference was absent for bilirubin, hemoglobin and chyle, but was significant for heparin.

Evaluation Studies as Topic↗
PubMed1998

[A case of imported paratyphoid fever associated with Giardia lamblia and Isospora belli infection].

We report a case of imported paratyphoid fever associated with Giardia lamblia and Isospora belli infection. The patient was a 23-year-old Japanese female with complaints of high grade fever and diarrhea after 10 days traveling to Nepal. Salmonella Paratyphi A was isolated from the blood and fecal cultures on admission and Ciprofloxacin of 200 mg tid was administered for 14 days. Fecal examination revealed cysts of G. lamblia at the same time and metronidazole of 250 mg tid for 7 days was effective for their eradication. During the follow-up studies oocysts of I. belli were found and cotrimoxazole of 960 mg bid for 10 days was effective for their eradication. Fecal examinations on parasites which is rare in Japan such as I. belli are recommended to the cases returning from tropical areas.

Adult↗
PubMed1998

[Quantitation of viral load in patients infected with HIV-1 subtype E or A].

Quantitation of viral load in a HIV infected person gives important information for monitoring of the clinical status of the patients and evaluation of anti viral effects of admininstred drugs. Although conventional Amplicor HIV-1 monitor system (Roche's conventional method) is used widely, the sensitivity of this system is not enough for measurement of subtype E and A giving lower titer of these subtype viruses than the actual quantity. In Japan, HIV-1 subytpe B cases used to be predominant but recently subtype E cases are increasing especially among heterosexuals thus it becomes required to increase the sensitivity of measurement of HIV-1 RNA of subtype E or A. Therefore we establised the Kanagawa primer method using newly developed subtype E and A primers added to the primers of Roche's conventional method. The results were compared with the conventional Amplicor and also with Roche's new version method which contained new primers. Kanagawa primer method gave 4 to 16 times more sensitive results as compared with Roche's conventional method for subtype E measurement. As for subtype A case, Kanagawa primer method gave a value 1.2 x 10(4) copies/ml while it was undetectable by Roche's conventional method. Roche's new version method showed equal sensitivity of Kanagawa primer method. As for subtype B, the results of these three methods showed no difference. Addition of our newly developed subtype E and A primers to the Roche's conventional method enabled to measure subtype E and A with high sensitivity. For quantitative measurement of HIV-1 RNA, it is important to consider the subtype of the virus in test samples.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Characterization of the hemorrhagic reaction caused by Vibrio vulnificus metalloprotease, a member of the thermolysin family.

Vibrio vulnificus is an opportunistic human pathogen causing wound infections and septicemia, characterized by hemorrhagic and edematous damage to the skin. This human pathogen secretes a metalloprotease (V. vulnificus protease [VVP]) as an important virulence determinant. When several bacterial metalloproteases including VVP were injected intradermally into dorsal skin, VVP showed the greatest hemorrhagic activity. The level of the in vivo hemorrhagic activity of the bacterial metalloproteases was significantly correlated with that of the in vitro proteolytic activity for the reconstituted basement membrane gel. Of two major basement membrane components (laminin and type IV collagen), only type IV collagen was easily digested by VVP. Additionally, the immunoglobulin G antibody against type IV collagen, but not against laminin, showed sufficient protection against the hemorrhagic reaction caused by VVP. Capillary vessels are known to be stabilized by binding of the basal surface of vascular endothelial cells to the basement membrane. Therefore, specific degradation of type IV collagen may cause destruction of the basement membrane, breakdown of capillary vessels, and leakage of blood components including erythrocytes.

Animals↗
PubMed1998

Improved cardiac function after catheter ablation in a patient with type B Wolff-Parkinson-White syndrome with an old myocardial infarction.

A 67-year-old man was admitted to hospital for the treatment of exertional dyspnea. He suffered from congestive heart failure due to an old inferior myocardial infarction with type B Wolff-Parkinson-White syndrome. Asynchronous wall motion caused by pre-excitation through a right-side bypass tract caused his cardiac function to deteriorate. Catheter ablation of the bypass tract increased the ejection fraction, and improved his symptoms, prior to surgical revascularization.

Aged↗
PubMed1998

[Measurement of coronary flow reserve using adenosine 5'-triphosphate in dogs].

Adenosine 5'-triphospate (ATP) was compared with adenosine and papaverine for the measurement of coronary flow reserve in 12 anesthetized dogs. Intracoronary bolus injection of ATP (1 ml, 1-500 microM) produced a dose dependent increase in the blood flow of the left anterior descending artery, which attained the plateau at the dose of 100 microM. The ratio of peak to resting coronary flow volume (coronary flow reserve) with 100 microM of ATP (3.5 +/- 0.5) was similar to that with 200 microM of adenosine (4.0 +/- 0.7) and 50 mM of papaverine (3.7 +/- 0.8). Hemodynamic variables did not change after administration of each drug, except left ventricular regional wall motion abnormality during papaverine injection. The coronary flow reserve as measured after intracoronary ATP administration (100 microM) decreased as the grade of stenosis of the left anterior descending artery progressed. In addition, the flow reserve was similar to that of adenosine or papaverine administration at each stenosis grade. Intravenous administration of ATP (1,000 micrograms/min) caused a similar increase in coronary blood flow as intracoronary ATP injection (100 microM). However, premedication with 8-phenyltheophylline, an adenosine receptor blocker, significantly suppressed the coronary dilatory effect of intravenous ATP and intracoronary adenosine but not the effect of intracoronary ATP. These results indicate that intracoronary ATP is useful for measuring coronary flow reserve and that its coronary dilatory effect is not mediated by metabolysis to adenosine.

Adenosine↗
PubMed1998

[Multiple overlapping Wiktor stenting for the treatment of diffuse lesions of small coronary arteries].

This study evaluated the usefulness of multiple overlapping stenting for the treatment of a diffuse lesion in a single and small coronary artery. We studied 48 consecutive patients with a lesion of a vessel with reference diameter < 3.0 mm who received Wiktor stent implants due to suboptimal result or threatened closure after plain old balloon angioplasty (POBA). The patients were divided into 2 groups: Group D, 18 patients with a diffuse lesion with length > or = 15.0 mm who were treated with 2 overlapping Wiktor stents; and Group S, 30 patients with a discrete lesion who were treated with a single Wiktor stent. Two patients with a discrete lesion were not included in Group S because of failure of stenting. Stenting was successful in all patients in Group D. One patient in Group S developed subacute thrombosis after stenting. Follow-up angiography was performed after 6 months. Before treatment, the lesion lengths in Groups D and S were 24.2 +/- 10.0 and 9.2 +/- 4.4 mm, the reference diameters were 2.56 +/- 0.32 and 2.69 +/- 0.33 mm, and the minimal lumen diameters were 0.42 +/- 0.34 and 0.53 +/- 0.40 mm, respectively, with no significant difference in the latter 2 parameters. Restenosis occurred in 72% and 30% (p = 0.01) and revascularization of the target lesion was successful in 67% and in 30% (p = 0.03), in Groups D and S, respectively, both significantly higher in Group D. Follow-up study revealed that the minimal lumen diameter and the net gain were significantly greater in the overlapping portion of the 2 stents than in the proximal and distal portions in Group D, with no significant difference in restenosis rate between these 3 portions. Multiple overlapping stenting using Wiktor stents is useful for diffuse lesions with unfavorable results after POBA even if the affected vessel is smaller than 3.0 mm. However, patients should be carefully observed because restenosis occurs frequently.

Aged↗
PubMed1997

Synthesis and evaluation of novel fluorinated methotrexate derivatives for application to rheumatoid arthritis treatment.

An ongoing search for new antifolate drugs useful against rheumatoid arthritis (RA) led us to prepare new methotrexate (MTX) derivatives containing enantiomerically pure L-erythro- or L-threo-gamma-fluoroglutamic acid. The derivatives in which the phenyl ring was replaced by a 3'-substituted phenyl or methylthiophene ring showed potent immunosuppressive activities, including in vitro inhibition of mitogen responses to both T and B cells and in vivo inhibition of antibody production in mice. These compounds also exhibited inhibitory activity in adjuvant arthritis in rats. Their toxicity was lower than that of MTX, which was probably due to the strong electronegativity of fluorine, which increases the acidity of the gamma-carboxyl group and thereby decreases polyglutamylation in normal cells. These results revealed the potential of the fluorinated MTX derivatives as candidate drugs for the treatment of RA.

Animals↗
PubMed1997

Postpartum adrenal, pituitary and ovarian functions in dairy cows.

Postpartum stress and the resumption of pituitary and ovarian functions were investigated in 29 dairy cows during the first month after calving. Adrenocorticotropic hormone (ACTH, 25 i.u., IM) challenge tests for adrenal function at 8 and 22 days postpartum and gonadotropin releasing hormone (GnRH, 50 micrograms IM) challenge tests for pituitary function at 7 and 21 days postpartum were conducted. Ovarian function, particularly the interval to first ovulation, was evaluated through weekly rectal palpation and ultrasonographic examination, as well as thrice weekly milk progesterone levels. Elevated basal cortisol levels were found in 24.1% and 20.7% of cows at 8 and 22 days postpartum, respectively. Adrenal response to ACTH was similar at 8 and 22 days postpartum with low, medium and high peak responses in 13.8%, 62.1% and 24.1% of cows, respectively. A moderate correlation was observed between basal and peak cortisol levels. Peak pituitary luteinizing hormone (LH) response was low in 65.5%, medium in 27.6% and high in 6.9% of cows at 7 days postpartum. Pituitary responsiveness improved by day 21 with low in 34.5%, medium in 37.9% and high in 27.6% of cows. About a week after calving, a negative correlation between peak cortisol and peak LH levels was observed. First ovulation occurred in 28%, 48% and 17% of postpartum cows during the second, third and fourth week, respectively. These results indicate a negative effect of peak cortisol levels on pituitary responsiveness to GnRH stimulation during the first week, altered adrenal and pituitary function in a third of the cows until the third week and restoration of ovarian function in most cows (93%) a month after parturition.

Adrenal Glands↗
PubMed1997

[Simple method for typing human immunodeficiency virus type I (B, E) by PCR and chronological change of distribution of subtype (B to E) in Japan].

We analyzed the clade distribution of B and E in HIV-1 isolates in Japan by a nested PCR method using 5'-CCCACAAGATTTAAATATG-3' of the gag gene as clade B primer and 5'-CCCACAAGATTTAAACTCC-3' of the gag gene as clade E primer. Seventy-two anti-HIV-1 confirmatory positive serum samples were collected during a period of 1991-1996 in two hospitals in Yokohama City. Peripheral blood mononuclear cells were obtained from the buffy coat of these samples and extracted DNA were used for nested PCR. The 72 cases comprised of 11 Japanese hemophiliacs, 14 Japanese male homosexuals, 19 Japanese male heterosexuals, 5 Japanese female heterosexuals and 23 Thai female heterosexuals. Of these 36 were clade B and 35 were clade E and one case showed positive PCR results for both B and E primers. Almost all male Japanese hemophiliacs and homosexuals in our sample have clade B, while the female Thai heterosexuals have clade E, irrespective of the year of isolation. As for Japanese male heterosexuals, through 1993, clade B was predominant but since 1994, the predominate clade switched to clade E. Although the number of Japanese female heterosexuals in our sample is small, clade B was isolated in 2 cases even after 1994.

Female↗
PubMed1997

A comparison of blood pressure changes in phacoemulsification surgery with topical and retrobulbar block local anesthesia: part II.

Although we recently compared blood pressure (BP) changes during cataract surgery between groups that received topical and retrobulbar block anesthesia, a study has not been conducted in which patients were matched for age and sex. To draw more meaningful conclusions, we conducted an age- and sex-matched study in which the daily, pre- and postoperative blood pressures of 1,398 cataract patients were compared. All surgeries were performed using the same method of phacoemulsification and aspiration with intraocular lens implantation under local anesthesia. The postoperative BPs of the retrobulbar injection group decreased significantly more than the topical application group. Even when the patients were hypertensive, the postoperative BPs decreased. Following retrobulbar block anesthesia, the BP decreased postoperatively to a greater extent than after topical anesthesia.

Administration, Topical↗
PubMed1997

Measurement of gestagen concentration in feces using a bovine milk progesterone quantitative test EIA kit and its application to early pregnancy diagnosis in the sow.

We attempted to measure the gestagen concentration in the feces of pigs by using a commercial bovine milk progesterone quantitative test EIA kit, and investigated the possibility of applying of this method of gestagen concentration measurement to early pregnancy diagnosis in the sow. Feces were collected from the rectum of the pig, and 0.5 g of the feces was placed in 20 ml of distilled water, stirred, and centrifuged. The supernatant was used as the fecal solution for measurement of gestagen. The procedure used for measuring gestagen in feces was the same as that for the measurement of progesterone in milk, except that a standard fecal gestagen solution (0.5-30.0 ng/ml) was prepared by the authors in the laboratory. The sensitivity of measurement using this method was 0.80 ng/ml, or 32.0 ng/g of fecal weight. The recovery was 105.2-105.6%. Intra-assay coeffecients of variation (CVs) were 2.8-8.5%. The interassay CVs were 7.4-10.2%. Gestagen concentrations in feces measured by the present method and progesterone concentrations in peripheral plasma, collected at the same time as the feces were highly correlated (r = 0.98, p < 0.001). The criteria for diagnosis of pregnancy based on the fecal gestagen level was positive for a gestagen level of > or = 200 ng/g and negative for a gestagen level of < 200 ng/g. When fecal gestagen measurements were applied to early pregnancy diagnosis in 149 sows, the accuracy of diagnosis from day 21 to day 25 after the last mating was 96.2% for positive cases (102/106) and 95.3% for negative cases (41/43). Thus, the results of this study show the quantitative measurement of the fecal gestagen concentration in the sow using a bovine milk quantitative test EIA kit is a practical method for early pregnancy diagnosis.

Animals↗
PubMed1997

Radioimmunoassay of saliva estrone sulfate in pregnant sows.

The aim of this study was to establish radioimmunoassay (RIA) for saliva estrone sulfate (E1S), and to elucidate changes in saliva E1S during pregnancy in the sow. Saliva E1S was extracted using a commercially available solid phase column, and the E1S fraction obtained was subjected to RIA. The sensitivity of the RIA was 29.7 pg/tube. The intra- and inter-assay coefficients of variation were 5.5-8.4% and 13.1-19.5%, respectively. Mean recovery for E1S added to saliva samples was as high as 99.9%. A significant positive correlation (r = 0.54, n = 69, p < 0.01) existed between saliva and plasma E1S concentrations. During gestation, the changing patterns of saliva and plasma E1S concentrations were essentially the same, and two peaks of E1S concentrations were observed, one around day 30 and another just before parturition, although E1S concentrations in saliva remained at only 2.4-38.1% (mean 11.4%) of those in plasma E1S. Thus, the present study has made it possible to measure saliva concentrations of E1S and demonstrated a high degree of positive correlation between saliva and plasma E1S concentrations. These results suggest that diagnosis of early pregnancy and of normal or abnormal fetal development could be made by measurements of E1S in saliva.

Animals↗