Effects of overhydration, Kt/Vurea, ß2-microglobulin on coronary artery calcification and mortality in haemodialysis patients.

AIM: We studied the effects of overhydration (OH), Kt/Vurea and ß2-microglobulin (ß2-MG) on coronary artery calcification and mortality in patients undergoing haemodialysis (HD). METHODS: The Agatston coronary artery calcium score (CACS), postdialysis body composition using bioimpedance analysis, single-pool Kt/Vurea and predialysis ß2-MG at baseline were assessed and followed up for 3 years in patients undergoing HD. We performed logistic regression analyses for a CACS ≥400 and Cox proportional hazard analyses for all-cause and cardiovascular mortality. RESULTS: The study involved 338 patients with a median age of 67 (56-74) years, dialysis duration of 70 (33-141) months and diabetes prevalence of 39.1% (132/338). Patients with a CACS ≥400 (n = 222) had significantly higher age, dialysis duration, male prevalence, diabetes prevalence, C-reactive protein, predialysis ß2-MG, OH, extracellular water/total body water and overhydration/extracellular water (OH/ECW) but significantly lower Kt/Vurea than patients with a CACS <400 (n = 116) (p < .05). OH/ECW, Kt/Vurea and predialysis ß2-MG were significant predictors of a CACS ≥400 (p < .05) after adjusting for age, dialysis duration, serum phosphate and magnesium. In all patients, cut-off values of OH/ECW, Kt/Vurea and predialysis ß2-MG for a CACS ≥400 were 16%, 1.74 and 28 mg/L, respectively. After adjusting for dialysis duration, OH/ECW ≥16%, Kt/Vurea ≥1.74 and ß2-MG ≥28 mg/L were significant predictors of 3-year all-cause mortality but not 3-year cardiovascular mortality. CONCLUSION: Higher OH/ECW, higher predialysis ß2-MG and lower Kt/Vurea values are significant risk factors for a CACS ≥400 and 3-year all-cause mortality in patients undergoing maintenance HD.

Absolute iron deficiency, coronary artery calcification and cardiovascular mortality in maintenance haemodialysis patients.

AIM: The effects of iron on vascular calcification in rats and vascular smooth muscle cells were recently reported, but clinical studies on iron and vascular calcification are scant. We studied the associations of absolute iron deficiency, coronary artery calcification and mortality in patients with maintenance haemodialysis (MHD). METHODS: Transferrin saturation (TSAT), ferritin, mean corpuscular haemoglobin (MCH) and Agatston coronary artery calcium score (CACS) were studied at baseline in MHD patients and followed up for 3 years. Cox proportional hazard analyses for mortality and linear regression analyses for CACS were performed. RESULTS: In 306 patients, the median age was 67 (56-81) years, dialysis duration was 76 (38-142) months, and diabetes prevalence was 42.5%. Fifty-two patients had died by 3 years. Patients with absolute iron deficiency (TSAT <20% and ferritin <100 ng/mL) (n = 102) showed significantly higher CACS (p = .0266) and C-reactive protein (p = .0011), but a lower frequency of iron formulation administration compared with patients without absolute iron deficiency at baseline (n = 204). Absolute iron deficiency was a significant predictor for 3-year cardiovascular (CV) mortality (hazard ratio: 2.08; p = .0466), but not for 3-year all-cause mortality. CACS was significant predictor for both 3-year CV and all-cause mortality (p <.05). Absolute iron deficiency and MCH were significant determinants of CACS (p < .05). CONCLUSION: MHD patients with absolute iron deficiency showed significantly higher CACS than others, and absolute iron deficiency was a significant risk factor for coronary artery calcification and 3-year CV mortality in MHD patients, but was not a significant predictor for 3-year all-cause mortality.

α1- and ß2-Microglobulin reduction ratios and survival in patients on predilution online haemodiafiltration.

AIM: ß2-Microglobulin (ß2-MG) and α1-microglobulin (α1-MG) have molecular weights of 11,800 and 33,000 Da, respectively. We studied the α1-MG and ß2-MG reduction ratios (RRs) and survival in patients on predilution online haemodiafiltration (Pre-OL-HDF). METHODS: Participants were 247 Pre-OL-HDF patients. α1-MG and ß2-MG RRs were assessed at baseline. Kaplan-Meier survival and Cox proportional hazard analyses were used. RESULTS: In 247 patients, the median age was 67 (56-73) years, the dialysis duration was 77 (46-150) months, and the diabetes prevalence was 47.4%. Twenty-two patients died over the 450-day study period. The mortality cut-off values using receiver-operating characteristic curves for the α1-MG and ß2-MG RRs were 20% and 80%, respectively. Survival rates were significantly (p < 0.05) higher in patients with α1-MG RRs ≥20% (n = 134) compared with patients with α1-MG RRs <20% (n = 113) and in patients with ß2-MG RRs ≥80% (n = 87) compared with patients with ß2-MG RRs <80% (n = 160). Cox models adjusting for diabetes and dialysis duration showed that α1-MG RR, ß2-MG RR, and pre- and postdialysis ß2-MG were risk factors for all-cause mortality; however, after additional adjustment for age, sex, and serum albumin, only ß2-MG RR and pre- and postdialysis ß2-MG were significant predictors of mortality (p < 0.05). α1-MG RRs were significantly correlated with ß2-MG RRs (ρ = 0.73, p < 0.0001) and serum albumin levels (ρ = 0.13, p < 0.05). CONCLUSION: In patients on Pre-OL-HDF, α1-MG RRs ≥20% and ß2-MG RRs ≥80% were associated with better survival, ß2-MG RR ≥80% and pre-and postdialysis ß2-MG levels were significant predictors of all-cause mortality, and α1-MG RR ≥20% may predict mortality.

Utility of CHA2DS2-VASc Score to Predict Mid-Term Clinical Outcomes in Hemodialysis Patients.

BACKGROUND: The CHA2DS2-VASc score has been widely used to predict stroke in patients with atrial fibrillation (AF). Recently, it was reported that the CHA2DS2-VASc score helps predict cardiovascular disease (CVD) or all-cause mortality in patients with or without AF. However, few reports have examined the association between this score and mortality in hemodialysis (HD) patients. METHODS: We analyzed 557 consecutive patients who initiated HD at our facilities between February 2005 and October 2017. The CHA2DS2-VASc score was calculated at the time of initiation of HD. Patients were then categorized into three groups according to their CHA2DS2-VASc scores: 0-1 (low), 2-3 (intermediate), and 4-9 (high). Multivariate Cox proportional hazards analysis was used to assess independent risk factors for 3-year all-cause mortality. RESULTS: During the 3-year follow-up period, 153 (27.5%) patients died (cardiovascular death: n = 88). According to multivariate analysis, serum albumin (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.43-0.85, p = 0.003), creatinine (HR 0.91, 95% CI 0.84-0.99, p = 0.049), and CHA2DS2-VASc score (HR 1.33, 95% CI 1.20-1.46, p < 0.001) were associated with 3-year all-cause mortality. Compared with patients in the low CHA2DS2-VASc score group, those in the intermediate- and high-score groups had a higher risk for all-cause and CVD mortality (all-cause mortality: HR 1.77, 95% CI 1.23-2.55, p = 0.002 and HR 2.94, 95% CI 1.90-4.53, p < 0.001, respectively; CVD mortality: HR 1.82, 95% CI 1.27-2.59, p = 0.001 and HR 2.85, 95% CI 1.88-4.31, p < 0.001, respectively). CONCLUSION: The CHA2DS2-VASc score is a valuable predictor of 3-year all-cause and CVD mortality in incident HD patients.

Convection volume, ß2-microglobulin and α1-microglobulin reduction ratios, and body composition in pre-dilution online haemodiafiltration.

AIM: The effect of convection volume (CV) in patients on pre-dilution online haemodiafiltration (Pre-OL-HDF) was evaluated. METHODS: We conducted a retrospective, cross-sectional study in 126 patients on Pre-OL-HDF. Dialysis conditions, laboratory data, and same day post-dialysis body composition measurements using bioimpedance spectroscopy were assessed. Patients were divided into two groups according to their CV: ≥ median value and < median value. Linear regression analyses for reduction ratios (RRs) of ß2-microglobulin and α1-microglobulin, and body composition, were conducted. RESULTS: Age, dialysis vintage, and CVs of the study patients were 64 ± 12 years, 81 (48-154) months, and 43.2 (38.5-55.9) L/session, respectively. The higher CV (≥ 43 L/session) group (n = 66) had significantly higher RRs of ß2-microglobulin and α1-microglobulin, lean tissue index, body cell mass index, total body water (TBW), extracellular water (ECW), and intracellular water (ICW) compared with the lower CV (< 43 L/session) group (n = 60, p <  .01). Serum albumin and fat tissue index were not significantly different between the groups. CV/ECW, CV/TBW, and CV/ICW but not un-adjusted CV, were significant determinants for ß2-microglobulin and α1-microglobulin RRs (p <  .05). Lean tissue and body cell mass indexes, but not the fat tissue index, showed significant associations with CV, and RRs of ß2-microglobulin and α1-microglobulin (p < kb.05). CONCLUSIONS: Among patients on Pre-OL-HDF, higher values in the lean tissue index and body cell mass index were observed in those with higher CV versus lower CV, and CV adjusted to body water may be useful to prescribe individualized conditions for Pre-OL-HDF.

Association and predictive value of geriatric nutritional risk index, body composition, or bone mineral density in haemodialysis patients.

AIM: Assess the association and predictive value of geriatric nutritional risk index (GNRI), body composition, and bone mineral density (BMD) in haemodialysis (HD) patients. METHODS: Laboratory data, body composition parameters measured via body composition monitor, and radius, lumbar spine, femoral neck BMD measured using dual energy X-ray absorptiometry were assessed in all subjects on HD or online haemodiafiltration (HDF) at baseline. Regression analysis for GNRI, Cox proportional hazard analyses and comparison of multiple receiver operating characteristic (ROC) curves were performed. RESULTS: Among all 264 patients, age was 65 ± 12 years and dialysis vintage was 79 (39-144) months. GNRI tertile (T)1, T2, and T3 were 88 (85-91), 94 (93-95), and 98 (97-101), respectively. Patients in GNRI T1 had lower fat tissue index (FTI), lean tissue index, and femoral neck, lumbar spine, and distal mid-third radius BMD, but higher overhydration/extracellular fluid than patients in GNRI T2 or T3 (P < .05). GNRI was significantly associated with FTI, lean tissue index, and femoral neck, lumbar spine, and distal mid-third radius BMD (P < .01). GNRI was a significant predictor of 2-year all-cause mortality (HR 0.92, P < .05). Area under the ROC curve for all-cause mortality using traditional risk factors (age, sex, diabetes mellitus, cardiovascular disease, use of vasopressors for dialysis-related hypotension, and C-reactive protein) was 0.67 and changed by adding GNRI (0.78, P < .05), FTI (0.75), or femoral neck BMD (0.66), respectively. CONCLUSION: Associations between GNRI, body composition, and BMD were confirmed in HD patients. Combining GNRI with traditional risk factors improved mortality prediction in HD patients.

Iron, coronary artery calcification, and mortality in patients undergoing hemodialysis.

OBJECTIVE: A high coronary artery calcification score (CACS) may be associated with high mortality in patients undergoing hemodialysis (HD). Recently, effects of iron on vascular smooth muscle cell calcification have been described. We aimed to investigate the relationships between iron, CACS, and mortality in HD patients. METHODS: We studied 173 consecutive patients who were undergoing maintenance HD. Laboratory data and Agatston's CACS were obtained at baseline for two groups of patients: those with CACS ≥400 (n = 109) and those with CACS <400 (n = 64). Logistic regression analyses for CACS ≥400 and Cox proportional hazard analyses for mortality were conducted. RESULTS: The median (interquartile range) age and duration of dialysis of the participants were 67 (60-75) years and 73 (37-138) months, respectively. Serum iron (Fe) and transferrin saturation (TSAT) levels were significantly lower in participants with CACS ≥400 than in those with CACS <400, although the serum ferritin concentration did not differ between the groups. TSAT ≥21% was significantly associated with CACS ≥400 (odds ratio 0.46, p<0.05). TSAT ≥17%, Fe ≥63 µg/dL, and ferritin ≥200 ng/mL appear to protect against 5-year all-cause mortality in HD patients, independent of conventional risk factors of all-cause mortality (p < 0.05). CONCLUSION: We have identified associations between iron, CACS, and mortality in HD patients. Lower TSAT was found to be an independent predictor of CACS ≥400, and iron deficiency (low TSAT, iron, or ferritin) was a significant predictor of 5-year all-cause mortality in HD patients.

Antifungal and Ichthyotoxic Sesquiterpenoids from Santalum album Heartwood.

In our continuing study on a survey of biologically active natural products from heartwood of Santalum album (Southwest Indian origin), we newly found potent fish toxic activity of an n-hexane soluble extract upon primary screening using killifish (medaka) and characterized α-santalol and ß-santalol as the active components. The toxicity (median tolerance limit (TLm) after 24 h at 1.9 ppm) of α-santalol was comparable with that of a positive control, inulavosin (TLm after 24 h at 1.3 ppm). These fish toxic compounds including inulavosin were also found to show a significant antifungal effect against a dermatophytic fungus, Trichophyton rubrum. Based on a similarity of the morphological change of the immobilized Trichophyton hyphae in scanning electron micrographs between treatments with α-santalol and griseofulvin (used as the positive control), inhibitory effect of α-santalol on mitosis (the antifungal mechanism proposed for griseofulvin) was assessed using sea urchin embryos. As a result, α-santalol was revealed to be a potent antimitotic agent induced by interference with microtubule assembly. These data suggested that α-santalol or sandalwood oil would be promising to further practically investigate as therapeutic agent for cancers as well as fungal skin infections.

Early arteriovenous fistula failure associated with mortality and major adverse cardiovascular events in patients undergoing incident hemodialysis.

BACKGROUND: Arteriovenous fistula (AVF) patency is important for patients undergoing hemodialysis. The association between early AVF failure and the prognosis, including all-cause mortality and major adverse cardiovascular events (MACE), has not been fully investigated. The present study was performed to investigate the association between early AVF failure and 3-year mortality, cardiovascular disease (CVD) mortality, and MACE. METHODS: We analyzed 358 patients who started hemodialysis in our institution from October 2008 to February 2020. We defined early AVF failure as cases requiring percutaneous transluminal angioplasty or reoperation within 1 year after AVF surgery. The patients were divided into two groups according to the presence or absence of early AVF failure, and the prognosis of each group was examined. The association between early AVF failure and outcomes (3-year all-cause mortality, CVD mortality, and MACE) was determined using Cox proportional hazards regression analysis. RESULTS: During the 3-year follow-up, 75 (20.9%) patients died (cardiovascular death: n = 39) and 145 patients developed MACE. According to the multivariable analysis, the early AVF failure group had a significantly higher risk of 3-year all-cause mortality (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.09-1.83; p = 0.009), CVD mortality (HR, 1.54; 95% CI, 1.29-2.08; p < 0.001), and MACE (HR, 1.68; 95% CI, 1.25-2.26; p < 0.001). When the patients were stratified by age, early AVF failure was associated with 3-year all-cause mortality in all groups except for the younger group (<65 years of age). CONCLUSIONS: Early AVF failure was associated with an increased risk of 3-year all-cause mortality, CVD mortality, and MACE.

Coronary artery calcification is a risk factor for intradialytic hypotension in patients undergoing hemodialysis.

INTRODUCTION: We investigated the association between intradialytic hypotension (IDH) and coronary artery calcification and their effects on mortality in hemodialysis (HD) patients. METHODS: Consecutive patients undergoing maintenance HD were enrolled. The study timeline included the baseline (day 1), exposure assessment (day 1-day 22), and outcome assessment (day 23-3 years) periods. IDH was defined as a nadir systolic blood pressure (SBP) of <100 mmHg or vasopressor use during at least 2 of 10 HD sessions in the exposure assessment period. The clinical data at baseline and the Agatston coronary artery calcium score (CACS) were assessed in the exposure assessment period. FINDINGS: The median age and dialysis vintage were 67 years [60-75 years] and 73 months [37-138 months], respectively. IDH occurred in 37 patients (21.4%), and the CACS was higher in the IDH group than in the non-IDH group (p = 0.08). IDH was associated with CACS, diabetes mellitus, mean predialysis SBP, and mean ultrafiltration volume (p < 0.05). The cutoff CACS for mortality was 1829 (sensitivity: 69%, specificity: 77%). In all, 45 all-cause deaths and 19 cardiovascular deaths occurred over 3 years. Patients with both IDH and a CACS of ≥1829 had a lower 3-year cumulative survival from cardiovascular death (66.7%) than those with a CACS of ≥1829 (80.3%), IDH (88.5%), or neither (95.5%) (p < 0.01). IDH, a CACS of ≥1829, and IDH + CACS of ≥1829 were predictors of 3-year all-cause and cardiovascular mortality (p < 0.05). The hazard ratio for cardiovascular mortality was highest in the group with IDH + CACS ≥ 1829. DISCUSSION: A high CACS may be a biomarker for IDH. Both IDH and CACS were risk factors for all-cause and cardiovascular mortality in patients undergoing HD, and there was a synergistic interaction between IDH and high CACS for cardiovascular mortality.

Synergistic Effects of the Geriatric Nutritional Risk Index and the Modified Creatinine Index for Predicting Mortality in Patients on Hemodialysis.

This study aimed to investigate whether a combined estimation of the geriatric nutritional risk index (GNRI) and the modified creatinine index (mCI) provides synergistic information for mortality in patients treated by chronic hemodialysis. We analyzed 499 patients on hemodialysis for five years. We set each cut-off value as the high (≥92) and low (<92) GNRI groups and the high (≥21 mg/kg/day) and low (<21 mg/kg/day) mCI groups, and divided them into four subgroups: G1, high GNRI + high mCI; G2, high GNRI + low mCI; G3, low GNRI + high mCI; and G4, low GNRI + low mCI. The survival rate was evaluated and time-to-event analysis was performed. All-cause death occurred in 142 (28%) patients. Kaplan−Meier curves showed that G2 and G4 had a significantly worse outcome (p < 0.05) than G1 but not G3. Using the multivariable-adjusted model, only G4 was significantly associated with all-cause mortality compared with G1. Our study suggests that the synergistic effects of the GNRI and the mCI are helpful in predicting all-cause mortality. The combination of these indices may be superior to a single method to distinguish patients who are well or moderately ill from potentially severely ill.

Relationship of serum magnesium level with body composition and survival in hemodialysis patients.

INTRODUCTION: A relationship between serum magnesium (Mg) and body composition parameters has not been reported in hemodialysis (HD) patients. We aimed to clarify whether serum Mg has any association with body composition parameters, or survival in HD patients. METHODS: This study included 215 consecutive maintenance HD patients. Laboratory data collection and postdialysis body composition analysis were performed at baseline. The patients were divided based on baseline serum Mg level tertiles (low, medium, and high Mg groups). Kaplan-Meier survival, logistic regression analyses and Cox proportional hazard analyses were conducted. FINDINGS: Among all patients, the median age and dialysis vintage were 73 (65-81) years and 44 (8-96) months, respectively. The serum Mg levels were < 2.3, 2.3-2.5, and > 2.5 mg/dL for the low (n = 67), middle (n = 76), and high (n = 72) Mg groups, respectively. Compared to other groups, low Mg group showed significantly higher age and C-reactive protein levels, but lower serum albumin, normalized protein catabolic rates and frequency of on-line hemodiafiltration. The low, middle, and high Mg groups differed significantly regarding body cell mass (fat-free mass without bone mineral mass and extracellular water) index (BCMI): [5.6 (4.2-6.8), 6.0 (4.8-8.1), 6.7 (4.9-7.5) kg/m2 , respectively] and overhydration/extracellular water ratio (OH/ECW) [11.7 (4.5-21.9), 4.8 (1.0-14.1), 8.5 (-0.5-15.0) %, respectively] but not regarding body mass index, lean tissue index, fat tissue index. Hypomagnesemia was significantly associated with BCMI [odds ratio (OR) [95% confidence interval (CI)]: 0.85 [0.73-1.00] and OH/ECW (OR [95% CI]: 1.03 [1.01-1.05]), respectively. Kaplan-Meyer 3-year survival rates were 53.6%, 69.7%, and 71.7% in low, middle, and high Mg groups, respectively. However, hypomagnesemia was not significantly associated with 3-year all-cause mortality independent of age, serum albumin and C-reactive protein. DISCUSSION: Hypomagnesemia was associated with lower BCMI, more pronounced OH/ECW and poorer Kaplan-Meier 3-year cumulative survival, but was not an independent risk factor for mortality in HD patients.

Two type IV pili of Vibrio parahaemolyticus play different roles in biofilm formation.

Vibrio parahaemolyticus RIMD2210633 has two sets of type IV-A pilus genes. One set is similar to that found in other Gram-negative bacteria, such as Pseudomonas aeruginosa, Vibrio cholerae (chitin-regulated pilus; ChiRP), and Vibrio vulnificus. The other is homologous to the genes for the mannose-sensitive hemagglutinin (MSHA) pilus. In this study, we analyzed the effects of the deletions in the pilin genes for each type IV pilus (the ChiRP and the MSHA pilus) on biofilm formation. Although the MSHA pilin mutant formed aggregates, the number of bacteria that attached directly to the coverslip was reduced, suggesting that this pilus contributes to the bacterial attachment to the surface of the coverslip. In contrast, the ChiRP mutant attached to the surface of the coverslip, but did not form aggregates, suggesting that ChiRP plays a role in bacterial agglutination during biofilm formation. These results suggest that the two type IV pili of V. parahaemolyticus contribute to biofilm formation in different ways. Both mutants showed a lower fitness for adsorption onto chitin particles than that of the wild type. Collectively, these data suggest that the use of two type IV pili is a refined strategy of V. parahaemolyticus for survival in natural environments.

Association between ENOS gene polymorphism and cardiovascular events in nondiabetic hemodialysis patients: a prospective study.

BACKGROUND: Synthesis of nitric oxide by endothelial nitric oxide synthase (ENOS) plays a key role in the atherosclerotic process. Several polymorphisms of the gene encoding ENOS are now known and have been investigated with respect to their influence on cardiovascular disease risk in the general population. The authors prospectively investigated whether ENOS gene polymorphisms determined the risk of cardiovascular complications in a cohort of hemodialysis patients. METHODS: A total of 335 nondiabetic hemodialysis patients were genotyped for 3 ENOS polymorphisms (T-786-->C, intron 4, and Glu298Asp polymorphism) and were followed up prospectively for a mean of 44.2 +/- 9.0 months. The end-points of the study were major cardiac, cerebrovascular, or peripheral vascular events. RESULTS: Two ENOS polymorphisms were associated with cardiovascular events: a T to C substitution at position -786 of the promoter and a deletion-insertion in intron 4 (the a allele having 4 repeats of a consensus sequence and the b allele having 5 repeats). A total of 84 subjects were -786C carriers (CC+TC), and 15 (18%) suffered from cardiovascular events compared with only 13 of 251 TT patients (5%). The relative risk of cardiovascular events was higher for -786C carriers compared with noncarriers (relative risk: 2.05, P = 0.0003). It was also higher for a allele carriers (intron 4 polymorphism) compared with noncarriers (relative risk: 1.97, P = 0.0005). CONCLUSION: T-786-->C polymorphism and intron 4 polymorphism, but not Glu298Asp polymorphism, of the ENOS gene can influence the risk of cardiovascular events in Japanese nondiabetic hemodialysis patients.

Biodegradation of dichloromethane by the polyvinyl alcohol-immobilized methylotrophic bacterium Ralstonia metallidurans PD11.

A dichloromethane (DCM)-degrading bacterium, Ralstonia metallidurans PD11 NBRC 101272, was immobilized in a polyvinyl alcohol (PVA) gel to use in a bioreactor for DCM treatment. After 4-month incubation of PVA gel beads with R. metallidurans PD11 and DCM in a mineral salt medium, the cells were tightly packed in the mesh of the gel. Forty beads of the gel in 10 ml of a batch system model showed effective activity degrading 500 and 1,000 mg l(-1) DCM within 2 and 3 h, respectively. Although reduction of pH due to accumulation of chloride ion liberated from DCM decreased the activity, it was recovered by adjustment to neutral pH. The activity of the immobilized cells was not affected by addition of nutrients which were preferentially utilized by R. metallidurans PD11, unlike the activity of the free-living cells. A continuous flow system with a column was more effective for rapid degradation of DCM. Thus, the PVA gel-immobilized cell of R. metallidurans PD11 is thought to be a prospective candidate to develop the bioreactor.

vpaH, a gene encoding a novel histone-like nucleoid structure-like protein that was possibly horizontally acquired, regulates the biogenesis of lateral flagella in trh-positive Vibrio parahaemolyticus TH3996.

A histone-like nucleoid structure (H-NS) is a major component of the bacterial nucleoid and plays a crucial role in the global gene regulation of enteric bacteria. Here, we cloned and characterized the gene for the H-NS-like protein VpaH in Vibrio parahaemolyticus. vpaH encodes a protein of 134 amino acids that shows approximately 55%, 54%, and 41% identities with VicH in Vibrio cholerae, H-NS in V. parahaemolyticus, and H-NS in Escherichia coli, respectively. The vpaH gene was found in only trh-positive V. parahaemolyticus strains and not in Kanagawa-positive or in trh-negative environmental strains. Moreover, the G+C content of the vpaH gene was 38.6%, which is lower than the average G+C content of the whole genome of this bacterium (45.4%). These data suggest that vpaH was transmitted to trh-possessing V. parahaemolyticus strains by lateral transfer. The vpaH gene was located about 2.6 kb downstream of the trh gene, in the convergent direction of the trh transcription. An in-frame deletion mutant of vpaH lacked motility on semisolid motility assay plates. Western blot analysis and electron microscopy observations revealed that the mutant was deficient in lateral flagella biogenesis, whereas there was no defect in the expression of polar flagella. Additionally, the vpaH mutant showed a decreased adherence to HeLa cells and a decrease in biofilm formation compared with the wild-type strain. Introduction of the vpaH gene in the vpaH-negative strain increased the expression of lateral flagella compared with the wild-type strain. In conclusion, our findings suggest that VpaH affects lateral flagellum biogenesis in trh-positive V. parahaemolyticus strain TH3996.

Induction of cellular immunity to varicella-zoster virus glycoproteins tested with pernasal coadministration of Escherichia coli enterotoxin in mice.

A mutant of Escherichia coli enterotoxin promotes the induction of cellular immunity to a live varicella vaccine (the Oka strain) as a mucosal adjuvant in mice. An investigation was carried out to determine which of the purified glycoproteins of the virus among three induced cellular immunity with a single nasal administration. Spleen cells from mice immunized nasally with the vaccine and toxin produced interleukin-2 (IL-2) at the same level on restimulation in vitro with glycoprotein H: glycoprotein L (gH:gL), gB, and gE:gI, but not IL-4. The spleen cells from mice immunized with gH:gL, gB, or gE:gI and toxin produced IL-2 on restimulation with gH:gL, gB, or gE:gI, respectively, and the vaccine, but not IL-4. Immunization with gH:gL and the toxin showed increased thymidine uptake and production of IL-2 and interferon-gamma (IFN-gamma) of the spleen cells, but not IL-4, depending on the dose of gH:gL used for immunization and restimulation in vitro. Purified gE:gI and gB have been reported to be the strongest stimulators of cellular immunity to varicella upon subcutaneous injection and are useful as a subunit vaccine. All the glycoproteins tested are excellent stimulators of cellular immunity to the virus and itself on nasal co-immunization with the toxin.

Purification and partial characterization of a hemagglutinating factor (HAF): a possible adhesive factor of the diffuse adherent of Escherichia coli (DAEC)

O fator hemaglutinante (HAF) foi extraido e purificado a partir de amostra de Escherichia coli de aderencia difusa (DAEC), pertencente ao sorogrupo 0128 de E. coli enteropatogenica classica (EPEC). O peso molecular do HAF foi estimado em 18.000 Da usando SDS-PAGE de 66.000 Da empregando Sephadex G 100, o que sugere a estrutura do HAF consistir de 3 a 4 subunidades. O emprego da tecnica "gold immunolabeling" com antissoro especifico anti-HAF revelou que este valor nao e uma estrutura do tipo fimbria na superficie da bacteria...