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Biomedical subjects

A Wada

Publications and source records attributed to A Wada.

At least 199 records · Page 11Linked to original sources
PubMed1997

Potential risk factors associated with progressive renal damage in childhood urological diseases: the role of angiotensin-converting enzyme gene polymorphism.

PURPOSE: Experimental as well as human studies have established an important role for the renin-angiotensin system in the progressive deterioration of renal function. Recently genetic polymorphism in components of the renin-angiotensin system has been associated with several cardiovascular diseases, particularly variations in the angiotensin-converting enzyme gene that involve insertion (I) or deletion (D) of a 287 bp fragment. The D variant has been associated with myocardial infarction and cardiac hypertrophy. MATERIALS AND METHODS: To assess whether this genetic variant is associated with worse prognosis in renal disorders we evaluated 70 children with congenital urological abnormalities, since a substantial number have progressive renal deterioration even after early corrective intervention. Renal deterioration was assessed by the presence or absence of radiographic evidence of parenchymal damage and serum creatinine. RESULTS: Among patients with no radiographic renal parenchymal damage angiotensin-converting enzyme genotype distribution of II, ID and DD was 24, 67 and 9%, respectively. In contrast, a significantly different angiotensin-converting enzyme genotype distribution was observed in patients with evidence of parenchymal damage, that is 10, 49 and 41% for II, ID and DD, respectively (p < 0.05, chi-square 5.0). Mean serum creatinine plus or minus standard error in the former group was normal at 0.6 +/- 0.1 mg./dl., while in those with scarring it was elevated at 1.1 +/- 0.1 mg./dl., as expected. In patients with the DD genotype an overwhelming frequency of parenchymal damage was observed, that is of all 22 with that genotype 20 (91%) had parenchymal damage. CONCLUSIONS: Considered together, these studies suggest that there are differences in the distribution of angiotensin-converting enzyme gene polymorphism in patients with congenital urological abnormalities who have evidence of renal parenchymal damage versus those who do not have such damage. Given that this genetic variation activates the renin-angiotensin system and this activation may be particularly robust in the kidney, we propose that the genotype of an individual independent of other factors modifies the likelihood of parenchymal loss in this setting.

Adolescent↗
PubMed1997

[Isolation of enterohemorrhagic Escherichia coli (O157:H7) by an immunomagnetic separation method].

Three sporadic cases of enterohemorrhagic Escherichia coli (EHEC) O157 infection which occurred in Kanagawa in 1996 were investigated. In an attempt to determine sources of the infection, a novel method of immunomagnetic separation (IMS) was employed to isolate the bacterium from feces, foods, and other associated items. In the first case, strains of EHEC O157:H7 producing Vero toxin (VT) 2 were isolated from both feces of the patient and suspected food (cattle liver) kept at a restaurant, and the strains were found to be genotypically identical through an analysis of pulsed-field gel electrophoresis (PFGE). Subsequent investigation in the meat processing store, from which the above cattle liver had been retailed to the restaurants revealed that the store was contaminated with EHEC O157:H7 producing both VT1 and VT2. In the second case, a strain isolated from the patient was EHEC O157:H7 producing both VT1 and VT2 while strains isolated from the patient's family (without apparent symptom) and the suspected facility were O137:NM producing VT2. PFGE analysis indicated that the latter two strains were genotypically identical, suggesting that the facility thus contaminated with EHEC O157 caused the infection in question. In the third case, EHEC O157:NM producing VT2 was isolated from 4 out of 7 family members including the patient, and these strains were found to be genotypically identical by subsequent PFGE analysis. Source of the infection was, however, not determined due to lack of suspected food items. In this context, four slaughterhouses in Kanagawa Prefecture were investigated for presence of EHEC O157. As a result, strains of EHEC O157:H7 producing VT1 and VT2 were isolated from the contents of cattle's distal colon and surface of the skinned carcasses. Additional attempt was also made to determine a possibility of river water being contaminated with EHEC O157. The bacterium was, however, not isolated from water samples collected from 4 major rivers in the prefecture (at 10 collecting sites). Experiments were undertaken in order to evaluate the use of IMS in isolation of EHEC O157 from food items, with different pre-enrichment media and conditions. The results indicated that pre-enrichment by trypticase soy broth at 36 degrees C for 6 h followed by inoculating onto sorbitol MacConkey agar plate containing cefixime and tellurite was most appropriate to isolate EHEC O157 strains.

Adolescent↗
PubMed1997

Nitrite reductase from Pseudomonas aeruginosa induces inflammatory cytokines in cultured respiratory cells.

Persistent infection with Pseudomonas aeruginosa increases interleukin-8 (IL-8) levels and causes dense neutrophil infiltrations in the airway of patients with chronic airway diseases. To investigate the role of P. aeruginosa infection in IL-8 production in the airway of these patients, we examined whether cell lysates of P. aeruginosa could cause IL-8 production from human bronchial epithelial cells. Diluted sonicated supernatants of P. aeruginosa (SSPA) with a mucoid or nonmucoid phenotype stimulated human bronchial epithelial (BET-1A) cells to produce IL-8. In this study, we have purified a 59-kDa heat-stable protein with IL-8-inducing activity from the SSPA by sequential ion-exchange chromatography. The N-terminal sequence of this purified protein completely matched a sequence at the N-terminal part of the mature protein of nitrite reductase from P. aeruginosa. In addition, immunoblotting with a polyclonal immunoglobulin G (IgG) against recombinant Pseudomonas nitrite reductase demonstrated a specific binding to the purified protein. Furthermore, the immunoprecipitates of the SSPA with a polyclonal IgG against recombinant nitrite reductase induced a twofold-higher IL-8 production in the BET-1A cell culture than did the immunoprecipitates of the SSPA with a control IgG. These lines of evidence confirmed that Pseudomonas nitrite reductase was responsible for IL-8 production in the BET-1A cells. The purified nitrite reductase induced maximal expression of IL-8 mRNA in the BET-1A cells at 1 to 3 h after stimulation, and the IL-8 mRNA expression declined by 8 h after stimulation. New protein translation was not required for nitrite reductase-mediated IL-8 mRNA expression in the BET-1A cells. Nitrite reductase stimulated the BET-1A cells, as well as human alveolar macrophages, pulmonary fibroblasts, and neutrophils, to produce IL-8. In contrast, nitrite reductase induced significant levels of tumor necrosis factor alpha and IL-1beta protein only in human alveolar macrophages. These data support the notion that nitrite reductase from P. aeruginosa induces the production of inflammatory cytokines by respiratory cells and may contribute to the pathogenesis of chronic airway diseases and persistent P. aeruginosa infection.

Bronchi↗
PubMed1997

Temperature-dependent regulation of the ribosomal small-subunit protein S21 in the cyanobacterium Anabaena variabilis M3.

The rpsU gene, which encodes the ribosomal small-subunit protein S21 in Anabaena, is not a part of the macromolecular-synthesis operon as in most enterobacteria but rather is located downstream of the rbpA1 gene, which encodes an RNA-binding protein. Two types of transcripts were detected for this gene cluster. The level of the major rbpA1-rpsU transcript was about 10 times higher at 22 degrees C than at 38 degrees C, whereas the minor monocistronic rpsU transcript was more abundant at the higher temperature. The level of the S21 protein in relation to total protein was three times lower at 38 degrees C than at 22 degrees C. Analysis of isolated ribosomes indicated that S21 was present at an equimolar ratio with regard to other ribosomal proteins at 22 degrees C but that its level decreased with temperature. Conversely, the relative abundance of S5 increased with temperature. A decrease in the level of S21 at high temperature was also found in Synechocystis, in which rpsU is located downstream of the rrn operon. These results suggest that S21 is involved in the adaptation to changes in temperature in cyanobacteria.

Amino Acid Sequence↗
PubMed1997

Molecular typing of enterohemorrhagic Escherichia coli O157:H7 isolates in Japan by using pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis (PFGE) was applied for molecular typing of 825 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates, most of which were from 19 outbreaks and 608 sporadic cases in Japan, mainly in May to August 1996. By PFGE, the EHEC O157:H7 isolates were classified into six types (type I to V and ND [nondescript]) and UT untypeable isolates. Fifty isolates from seven outbreaks in May to June and 60 isolates from patients with sporadic cases of infection showed almost identical PFGE patterns which differed in only 1 of 22 DNA fragments. They were classified into type I. Ninety-nine isolates from 10 other outbreaks and 156 isolates from patients in the Kinki area with sporadic cases of infection obtained in the early summer of 1996 showed identical PFGE patterns, suggesting that they were derived from one huge outbreak. They were classified into type II. Type IV EHEC isolates, which had only the stx2 gene, caused another outbreak in a primary school in June. EHEC isolates of two other types, types III and V, were not related to the outbreak but were isolated in several parts of Japan. ND EHEC isolates included a variety of patterns which could not be classified into either of the types mentioned above. Twenty-five isolates could not be analyzed due to degradation of their genomic DNAs and were represented as UT. These results indicate that EHEC O157:H7 strains with various PFGE types have already spread to Japan and caused the multiple outbreaks and sporadic infections in Japan in the summer of 1996.

Bacterial Typing Techniques↗
PubMed1997

Nitric oxide-dependent and -independent norepinephrine release in rat mesenteric arteries.

The role of nitric oxide (NO) in endogenous norepinephrine (NE) release in the perfused isolated rat mesenteric vasculature was examined. NE overflow elicited by electrical field stimulation (EFS) at various frequencies was significantly smaller at 24 than at 37 degrees C. The pressor response upon EFS at 8 and 10 Hz, however, was higher at 24 than at 37 degrees C. When production of NO was blocked by N omega-nitro-L-arginine (L-NNA), NE overflow upon EFS at each frequency of stimulation was diminished by 50% at 37 degrees C but remained unchanged at 24 degrees C, whereas the pressor response elicited by EFS became greater at 37 than at 24 degrees C. These effects of L-NNA were reversed by L-arginine, but not by its D-enantiomer. Sodium nitroprusside, an NO donor, increased EFS-elicited NE overflow at 24 degrees C but had no effect at 37 degrees C. These results demonstrate that NE release is NO dependent and NO independent. The NO-dependent mechanism is more sensitive to cooling than the NO-independent mechanism. The increase in EFS-elicited perfusion pressure at 24 degrees C may be due to reduction in synthesis of NO (a potent vasodilator), thus unmasking the effect of NE and other noncatecholamine vasoconstrictors.

Animals↗
PubMed1997

Chronic effects of ANG II antagonist in heart failure: improvement of cGMP generation from ANP.

To evaluate the effects of endogenous angiotensin II (ANG II) on the development of congestive heart failure (CHF), we examined cardiorenal and hormonal factors after chronic administration of the ANG II type 1 receptor antagonist TCV-116 in dogs with CHF induced by rapid right ventricular pacing. After 8 days of pacing, TCV-116 administration [1 (group 1) or 3 mg.kg-1.day-1 (group 2)] was started and continued until the 22nd day. TCV-116 was found to have protected the deterioration of cardiorenal functions and the activation of neurohormonal factors. Although there was no significant difference in the pulmonary capillary wedge pressure or plasma atrial natriuretic peptide (ANP) level between the TCV-116-treated groups (354 +/- 85 and 364 +/- 29 pg/ml for groups 1 and 2, respectively) and the vehicle group (385 +/- 20 pg/ml), the plasma guanosine 3',5'-cyclic monophosphate (cGMP) levels, a second messenger of ANP, were twofold higher in TCV-116-treated groups (49.4 +/- 10.2 and 50.6 +/- 7.7 pmol/ml for groups 1 and 2, respectively) than in the vehicle group (24 +/- 4.0 pmol/ml), with a high correlation between the plasma ANP and cGMP levels (r = 0.90; P < 0.05). These findings indicate that endogenous ANG II has important roles in hemodynamics and renal functions during the development of CHF, which may be due, in part, to a reduction in endogenous ANP activity, suggesting the usefulness of an ANG II-receptor antagonist against the development of CHF.

Aldosterone↗
PubMed1997

Humoral factor(s) produced by pressure overload enhance cardiac hypertrophy and natriuretic peptide expression.

Chronic pressure overload is known to increase cardiac mass and expression levels of both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNAs. Although mechanical stretching of cardiac myocytes could cause these changes, humoral factor(s) secondary to pressure overload may also be involved. To dissociate humoral effects from the effects of mechanical loading on cardiac hypertrophic responses, we examined expression of ANP and BNP at both mRNA and protein levels and proportions of myosin isoforms in transplanted cervical hearts that were mechanically unloaded under conditions with or without hypertension by aortic coarctation. Seven days after transplantation, cardiac atrophy that usually occurs in transplanted hearts without hypertension by coarctation was prevented in the transplanted hearts with hypertension by coarctation. The levels of expression of ANP and BNP mRNAs were increased in the transplanted hearts with relative to those without hypertension by coarctation. The plasma level of angiotensin II was higher in rats with than without hypertension by coarctation. Plasma endothelin-1 levels were not significantly different between the two groups. In addition, levels of expression of ANP and BNP mRNAs were increased in the transplanted hearts without hypertension relative to those in the in situ hearts. The proportion of the V3 myosin isoform was also increased in the transplanted hearts without hypertension relative to the in situ hearts. These results indicate that humoral factor(s) secondary to the pressure overload produced by aortic coarctation enhanced the cardiac hypertrophic response and elevated the levels of mRNAs encoding these embryonic markers. Moreover, our findings regarding ANP and BNP expression in the transplanted hearts provide additional evidence that the fetal genes are reexpressed during the process of cardiac atrophy as well as in cardiac hypertrophy.

Angiotensin II↗
PubMed1997

Cerebral magnetic resonance T2 high intensities in end-stage renal disease.

BACKGROUND AND PURPOSE: The pathophysiological mechanisms that cause cerebral MR T2 high intensities in end-stage renal disease (ESRD) are unclear. We evaluated the incidence and the risk factors of T2-weighted MR brain high intensities in patients with ESRD. METHODS: We examined the degree of T2-weighted MR brain high intensities (high intensity score) and determined the variables that had an independent association with the occurrence of high intensities in 38 patients with ESRD before chronic dialysis treatment, 173 patients with essential hypertension, and 72 normotensive control subjects. RESULTS: The whole brain high intensity score was significantly higher in patients with ESRD than in the control subjects, but there was no significant difference in high intensity score between the ESRD and the hypertensive groups. Age, hypertension, and smoking were significant independent predictors of high intensities in a multiple logistic regression model. The distribution pattern of high intensities in ESRD patients was very similar to that obtained from hypertensive patients; the high intensity score was highest in the corona radiata and was lowest in the cerebellum. CONCLUSIONS: T2 high intensities on MR images of ESRD may reflect subcortical small-vessel alterations induced by hypertension.

Adult↗
PubMed1997

Dilute down lethal: a new lethal mutation in Japanese quail.

"Dilute down lethal (DDL)" is a new mutation of Japanese quail (Coturnix japonica). Neonatal plumage of the DDL mutant is the same as the wild type in pattern, but its coloration is slightly lighter than that of the wild type. In addition to the down color abnormality, some DDL chicks have bent digits. All DDL chicks die within three days of age. Genetic analysis revealed that the DDL mutation is controlled by an autosomal recessive gene. The proposed gene symbol is ddl.

Animals↗
PubMed1997

A study on the beryllium lymphocyte transformation test and the beryllium levels in working environment.

The relationship between airborne concentration of beryllium in the working environment and workers' beryllium lymphocyte transformation test (Be-LTT) values was examined based on data obtained from a four-year survey (1992-1995) conducted at beryllium-copper alloy manufacturing factories. This study showed that the T cells of workers continuously exposed to beryllium of more than 0.01 microgram/m3 could be activated and that the cell-mediated immune response of workers could be promoted. On the other hand, the Be-LTT of workers exposed to beryllium levels of less than 0.01 microgram/m3 was shown to be unaffected by beryllium. These findings suggest that beryllium sensitization is not manifested when level of beryllium in working environment are less than 0.01 microgram/m3. Therefore, in such cases workers do not develop Chronic beryllium disease (CBD). We concluded that the Be-LTT can be applied as a medical indicator to detect the development of CBD.

Adult↗
PubMed1997

[Studies on enrichment broth for verotoxin-producing Escherichia coli (VTEC) O157].

Growth of verotoxin-producing Escherichia coli (VTEC) O157 in conventionally recommended pre-enrichment broth media at different temperatures was evaluated. In addition, sensitivity of VTEC O157 isolates to several antibacterial drugs, which were added to the selective enrichment broth, was tested. All five isolates of VTEC O157 tested grew well in trypticase soy broth (TSB) at 36 degrees C and 42 degrees C, while the growth of one isolate was markedly suppressed in TSB supplemented with cefixime (CFIX), potassium tellurite (PT), and vancomycin (TSB-CTV) even at 36 degrees C. A significant growth suppression was also observed in three of the isolates cultured in novobiocin (NB)-supplemented modified EC broth (mEC-NB) at 42 degrees C. In mEC-NB after 24-hr incubation at 36 degrees C, the five VTEC O157 isolates grew well, although one isolate was slightly suppressed during the first 8 hours. Minimum growth inhibitory concentrations of CFIX, NB and PT for a total of 90 clinical and environmental isolates of VTEC O157 were all above the concentrations usually prescribed for mEC-NB and TSB-CTV. These findings suggest that mEC-NB and TSB-CTV should be used at 36 degrees C for growth of VTEC O157 and that use of a nonselective pre-enrichment broth medium (i.e. TSB) together with a selective one (i.e. TSB-CTV or mEC-NB) is necessary for successful isolation of VTEC O157 from various specimens.

Aeromonas↗
PubMed1997

[Molecular analysis of enterohemorrhagic Escherichia coli O157:H7 isolates in Japan 1996 using pulsed-field gel electrophoresis].

Using pulsed-field gel electrophoresis(PFGE) with XbaI digestion, we analyzed 1,794 enterohemorrhagic Escherichia coli(EHEC) O157 isolates, which were derived from 16 outbreaks, sporadic cases, foods, beef fecal swabs, and environments in 1996 in Japan. They were classified into six types according to observed PFGE patterns. EHEC O157:H7 isolates from seven out of the 16 outbreaks showed very closely related patterns and those from other five outbreaks did the same pattern; in the former outbreaks, no common source could be identified, while in the latter outbreaks, radish sprout is thought to be the common cause of the infection. PFGE patterns of the remaining four outbreaks were not correlated to each other.

Animals↗
PubMed1997

Different responsiveness to nitric oxide-cyclic guanosine monophosphate pathway in cholinergic and tachykinergic contractions of the rabbit iris sphincter muscle.

PURPOSE: In the rabbit iris sphincter muscle, sodium nitroprusside (SNP), a nitric oxide (NO) donor, inhibits cholinergic contraction but does not affect tachykinergic contraction in vitro. The objectives of the current study were to clarify the mechanism for the different responsiveness to NO in cholinergic and tachykinergic muscular contractions, and to examine whether the mechanism for NO-induced inhibition of cholinergic muscular contraction is operative in vivo. METHODS: Iris sphincter muscle was dissected from the rabbit eye pretreated with or without endotoxin (lipopolysaccharide, LPS) in vivo. Cyclic guanosine monophosphate (cGMP) content in the iris sphincter muscle was determined by radioimmunoassay. The motor activity of the ring-shaped iris sphincter muscle was measured isometrically. Sodium nitroprusside, carboxy-2-phenyl-4,4,5,5,-tetramethyl-imidazoline-1-oxyl-3-oxide (C-PTIO, a scavenger of NO radicals), and 8-bromo cGMP (a permeable cGMP analogue) were administered between the first and second administrations of carbachol and neurokinin A, both of which had caused sustained contraction in the iris sphincter muscle. RESULTS: Sodium nitroprusside inhibited the contraction of the iris sphincter muscle caused by carbachol but had no effect on the contraction caused by neurokinin A. Application of C-PTIO significantly reduced SNP-induced cGMP accumulation in the muscle, as well as the SNP-induced inhibition of muscular contraction caused by carbachol. Neither carbachol nor neurokinin A influenced SNP-induced cGMP accumulation in the muscle. Induction of 8-bromo-cGMP significantly diminished the muscular contraction caused by carbachol but not that caused by neurokinin A. In vivo pretreatment of the eye with LPS increased, in a time-dependent manner, the cGMP accumulation in the iris sphincter muscle, which was significantly inhibited by pretreatment of NG-nitro-L-arginine methyl ester (an inhibitor of NO synthesis) in vivo. CONCLUSIONS: These results demonstrate that in rabbits the increase in cGMP accumulation induced by NO in the iris sphincter muscle is involved in the cholinergic contraction but not in the tachykinergic contraction, suggesting that different sensitivities to cGMP are essential for the different responsiveness to NO. Furthermore, the results of this study showed that the NO-cGMP pathway is operative in vivo and regulates iris sphincter muscle tone, at least when the eyes are infected with bacteria.

Animals↗
PubMed1997

Automated measurement of a constitutive isotype of serum amyloid A/SAA4 and comparison with other apolipoproteins.

A constitutive isotype of serum amyloid A (SAA4) is present mostly in high density lipoprotein (HDL) and a little in other lipoproteins. In this study, we developed an automated method for measuring SAA4 concentration in serum by kinetic nephelometry of anti-SAA4 antibody-coated latex agglutination. Rabbit antibodies generated by immunization of recombinant SAA4 were found to have no apparent reactivity with acute phase SAA. The values determined by this method and by the previous enzyme immunoassay showed good agreement (r = 0.862). Serum SAA4 values of 26 healthy adults ranged from 37-109 mg/L (mean; 62 mg/L). Their SAA4 concentrations were not significantly related with those of apolipoprotein A-I, A-II, B, C-II, C-III or E. Also, SAA4 did not correlate with cholesterol in preparation after removal of very low density lipoprotein and low density lipoprotein. These suggest the unique behavior of SAA4 in lipoprotein metabolism, while what contributes to variation of SAA4 levels in serum, especially in HDL, remains to be clarified.

Adult↗
PubMed1997

[General thoracic surgery in cardiac patients].

PURPOSE: To analyse the main cardiac risk factors responsible for immediate and late outcomes in patients undergoing thoracic surgeries. METHODS: We performed a retrospective analysis of 90 cases of cardiac patients submitted to non-cardiac thoracic surgeries. Surgeries were divided into greater ones and others and the heart diseases into severe and mild disease. We analysed immediate and late complications, and the mortality inside these groups. RESULTS: We found a greater morbi-mortality in the greater surgeries group and a greater late mortality in the severe heart disease group. There were evidences that the degree of the heart disease does not influence immediate outcome. CONCLUSION: The heart disease was not a limiting immediate risk for surgery.

Adult↗