Long-term impacts of endocrine-disrupting chemicals exposure on kidney function: A community-based cohort study

This study explores the extended renal effects of endocrine-disrupting chemicals (EDCs) exposure, a linkage already established with adverse health outcomes, notably chronic kidney disease. To delve deeper, the Chang Gung Community Research Center conducted a longitudinal study with 887 participants. Among them, 120 individuals were scrutinized based on EDC scores, analyzing 17 urinary EDCs and renal function. Findings revealed elevated mono-(2-ethylhexyl) phthalate (MEHP) and bisphenol A levels in higher EDC exposure cases. MEHP notably correlated with increased urinary albumin-to-creatinine ratio (UACR), predicting a > 15% decline in estimated glomerular filtration rate. Higher MEHP levels also hinted at declining renal function. UACR escalation linked significantly with specific EDCs: MEHP, methylparaben, nonylphenol, and 4-tert-octylphenol. This research underscores enduring renal hazards tied to environmental EDC exposure, particularly MEHP, emphasizing the urgent call for robust preventive public health strategies.

Performance of urinary C-C motif chemokine ligand 14 for the prediction of persistent acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Urinary C-C motif chemokine ligand 14 (CCL14) has been described as an effective marker for delayed recovery of acute kidney injury (AKI), yet its efficacy has been found to vary between different trials. The goal of this research was to assess the predictive performance of urinary CCL14 as a marker for persistent AKI.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched the PubMed, Embase, and Cochrane databases up to April 2023 for studies of adults (> 18 years) that reported the diagnostic performance of urinary CCL14. The sensitivity, specificity, number of events, true positive, and false positive results were extracted and evaluated. Hierarchical summary receiver operating characteristic curves (HSROCs) were used to summarize the pooled test performance, and the Grading of Recommendations, Assessment, Development and Evaluations criteria were used to appraise the quality of evidence.

RESULTS

We included six studies with 952 patients in this meta-analysis. The occurrence of persistent AKI among these patients was 39.6% (377/952). The pooled sensitivity and specificity results of urinary CCL14 in predicting persistent AKI were 0.81 (95% CI 0.72-0.87) and 0.71 (95% CI 0.53-0.84), respectively. The pooled positive likelihood ratio (LR) was 2.75 (95% CI 1.63-4.66), and the negative LR was 0.27 (95% CI 0.18-0.41). The HSROC with pooled diagnostic accuracy was 0.84.

CONCLUSION

Our results suggest that urinary CCL14 can be used as an effective marker for predicting persistent AKI.

Serum Cystatin C Levels Could Predict Rapid Kidney Function Decline in A Community-Based Population

BACKGROUND

Several biomarkers have been correlated with the prevalence and severity of chronic kidney disease (CKD); however, the association between biomarkers and rapid kidney function decline (RKFD) is unknown. This study aimed to evaluate the predictive performance of biomarkers to determine who is likely to develop RKFD in a healthy population.

METHODS

A community-based cohort of 2608 people residing in northern Taiwan were enrolled, and their renal function was followed annually from January 2014 to December 2019. The outcomes of interest were RKFD, defined as a 15% decrease in the estimated glomerular filtration rate (eGFR) within the first 4 years, and a decrease in eGFR without improvement in the fifth year. Clinical variables and potential predictors of RKFD, namely adiponectin, leptin, tumor necrosis factor-alpha, and cystatin C, were measured and analyzed.

RESULTS

The incidence of RKFD was 17.0% (105/619). After matching for age and sex at a 1:1 ratio, a total of 200 subjects were included for analysis. The levels of cystatin C and total vitamin D were significantly negatively correlated with eGFR. eGFR was negatively correlated with the levels of cystatin C and total vitamin D. Among the biomarkers, cystatin C showed the best predictive performance for RKFD (area under the receiver operating characteristic curve: 0.789). Lower serum cystatin C was associated with a higher rate of RKFD in healthy subjects. A generalized additive model showed that 0.82 mg/L was an adequate cut-off value of cystatin C to predict RKFD. Multivariable logistic regression analysis further indicated that low cystatin C and eGFR were independent predictors of the possibility of RKFD.

CONCLUSIONS

Serum cystatin C level could predict the possibility of RKFD. We suggest that a low cystatin C level should be considered as a risk factor for RKFD in healthy subjects.

Relationships Between Metabolic Body Composition Status and Rapid Kidney Function Decline in a Community-Based Population: A Prospective Observational Study

Obesity and metabolic syndrome are strong risk factors for incident chronic kidney disease (CKD). However, the predictive accuracy of metabolic body composition status (MBCS), which combines the status of obesity and metabolic syndrome, for rapid kidney function decline (RKFD) is unclear. The aim of this study was to investigate the relationship between MBCS and RKFD in a healthy population in a prospective community-based cohort study. In the current study, we followed changes in renal function in 731 people residing in northern Taiwan for 5 years. The participants were divided into four groups according to their MBCS, including metabolically healthy normal weight (MHNW), metabolically healthy overweight (MHOW), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight (MUOW). We evaluated traditional risk factors for CKD and metabolic profiles. The primary outcome was RKFD, which was defined as a 15% decline in estimated glomerular filtration rate (eGFR) within the first 4 years, and a reduction in eGFR which did not improve in the 5th year. During the study period, a total of 731 participants were enrolled. The incidence of RKFD was 17.1% (125/731). Multiple Cox logistic regression hazard analysis revealed that age, cerebrovascular accident, eGFR, urine albumin-to-creatinine ratio, use of painkillers, depressive mood, MUNW and MUOW were independent predictors of RKFD. After adjusting for age, sex, eGFR and total cholesterol, the participants with MUNW and MUOW had higher hazard ratios (HRs) for RKFD [HR: 2.19, 95% confidence interval (CI): 1.22–3.95 for MUNW; HR: 1.86, 95% CI: 1.21–2.87 for MUOW] than those with MHNW. Similar results were also observed in subgroup analysis of those aged above 65 years. On the basis of the results of this study, we conclude that MBCS was independently associated with RKFD, especially in the older adults. On the basis of our results, we suggest that MUNW and MUOW should be considered as risk factors for RKFD.

Dynamic Echocardiographic Assessments Reveal Septal E/e' Ratio as Independent Predictor of Intradialytic Hypotension in Maintenance for Hemodialysis Patients with Preserved Ejection Fraction

BACKGROUND

Intradialytic hypotension (IDH) is a frequent and grave complication of hemodialysis (HD). However, the dynamic hemodynamic changes and cardiac performances during each dialytic session have been rarely explored in patients having IDH.

METHODS

Seventy-six HD patients (IDH = 40, controls = 36) were enrolled. Echocardiography examinations were performed in all patients at the pre-HD, during-HD and post-HD phases of a single HD session. A two-way analysis of variance was applied to compare differences of echocardiographic parameters between IDH and controls over time. The risk association was estimated by using a logistic regression analysis.

RESULTS

The IDH patients had a higher ejection fraction during HD followed by a greater reduction at the post-HD phase than the controls. Significant decreases in septal ratios of transmitral flow velocity to annular velocity (E/e') over times were detected between IDH patients and controls after adjusting for gender, age and ultrafiltration (p = 0.016). A lower septal E/e' ratio was independently associated with IDH (OR = 0.040; 95% CI = 0.003-0.606; p = 0.02). In contrast, significant systolic and diastolic dysfunctions over time were found in diabetic IDH compared to non-diabetic counterparts.

CONCLUSION

The septal E/e' ratio was a significant predictor for IDH.

Xenoestrogen exposure and kidney function in the general population: Results of a community-based study by laboratory tests and questionnaire-based interviewing

BACKGROUND

Chronic kidney disease (CKD) is a growing concern worldwide. Exposure to xenoestrogens (XEs), such as phthalates, parabens, and phenols, lead to CKD. However, kidney function and its complex relationship with XEs, lifestyle, and dietary habits are not well understood.

METHODS

In the present cross-sectional community-based cohort study, we enrolled 887 subjects for a questionnaire-based interview and laboratory tests. XE exposure concerning lifestyle/dietary habits were evaluated using questionnaires. Urinary levels of 17XE metabolites were measured in 60 subjects with high exposure risk scores and 60 subjects with low exposure risk scores.

RESULTS

Univariate and multivariate linear regression showed that a high exposure score (β ± SE: 4.226 ± 1.830, P = 0.021) was independently negatively associated with eGFR in 887 subjects. Univariate and multivariate linear regression to urinary XEs and urine albumin creatinine excretion ratio (UACR) in 120 subjects indicated that ethylparaben (EP) (β: 1.934, 95% CI: 0.135-3.733, P = 0.035) was significantly associated with increased UACR. Multivariate regression analyses of the CKD subgroup (n = 38), after adjusting for age, showed that higher levels of mono-(2-ethylhexyl) phthalate (MEHP), EP, nonylphenol (NP), and benzophenone-3 (BP-3) were significantly associated with lower estimated glomerular filtration rate (eGFR). Higher urinary levels of MEHP (OR: 3.037, 95% CI: 1.274-7.241) were more likely associated with high exposure scores (>5 points), after adjusting for diabetes, gender, eGFR, age, Na, Ca, albumin, vitamin D, systolic blood pressure (SBP), white blood cell count, total bilirubin, aspartate transaminase, and heart rate. MEHP (β ± SE: 0.033 ± 0.009, P < 0.001) was also significantly positively associated with total exposure scores after applying multivariate linear regression analyses.

CONCLUSION

XE exposure scores obtained from the questionnaires were negatively associated with kidney function. Urinary metabolites of XEs, including EP, NP, BP-3, and MEHP, are potential risk factors for microalbuminuria and decline in kidney function. MEHP seemed to have the strongest correlation with high exposure scores and decline in kidney function.

Effective Preventive Strategies to Prevent Secondary Transmission of COVID-19 in Hemodialysis Unit: The First Month of Community Outbreak in Taiwan

Background: Dialyzed patients are vulnerable to coronavirus infection disease 2019 (COVID-19). The incidence and outcome of COVID-19 in hemodialysis (HD) patients in Taiwan remain unclear. A series of preventive measures were executed to combat COVID-19 transmission among HD patients. Methods: We carried out a series of forward-looking and practical preventive strategies of COVID-19 control in our HD center. Incidences of COVID-19 of our HD unit were compared with those of national and local estimates from a community outbreak from 15 May to 30 June 2021. Prognostic factors associated with mortality were analyzed. Results: The national incidence of COVID-19 was 0.062%; being highest in Taipei City (0.173%), followed by New Taipei City (0.161%) and Keelung (0.083%). The overall incidence in Keelung HD patients was 0.666%. One patient of our HD center contracted COVID-19 from the household; however, we have contained secondary transmission in our HD center by implementing strict preventive measures. The mortality rate of HD patients in Keelung was 66.6%. The median Ct value of HD patients was 17.53 (11.75–27.90) upon diagnosis. The deceased patients had a higher cardiac/thoracic ratio than alive (0.61 vs. 0.55, p = 0.036). Conclusions: Taking aggressive and proactive infection preventive measures impedes the secondary transmission of COVID-19 in HD facilities. COVID-19-associated mortality was high in HD patients, being the high cardiac-thoracic ratio, an important prognostic factor for clinical outcome of infected HD patients.

Renal function trajectories in hepatitis C infection: differences between renal healthy and chronic kidney disease individuals

Associations between hepatitis C virus (HCV) and chronic kidney disease (CKD) have been reported; however, differences of renal progression between general and CKD population remain to be elucidated in prospective studies. A total of 1179 participants, who have tested for anti-HCV antibody, were enrolled and prospectively followed for 3 years. The risks associated with HCV infection, in terms of incidence of CKD, annual estimated glomerular filtration rate (eGFR) changes and 50% decline of eGFR at 3-year from baseline, were compared between normal renal function subjects and CKD patients. Overall, 111 of 233 (47.6%) CKD patients and 167 of 946 (17.7%) non-CKD subjects had HCV infection. The crude incidence rates of CKD were 226.9 per 1000 person-years and 14.8 per 1000 person-years in in HCV and non-HCV infected patients, respectively. The adjusted hazard ratio of HCV infection for incident CKD was 7.9 (95% CI 5-12.7). The HCV-infected normal renal function subjects were independently associated with increased risks of eGFR decline in the 1-year, 2-year and 3-year, respectively. The risk associations remained significant in 50% decline of eGFR at 3 years models and in different subgroup analyses. The increases of risks of eGFR decline were also notorious among overall HCV-infected CKD patients. However, the risk associations were less prominent in subgroup analyses (elderly, women and diabetic patients). The findings highlighted the importance of viral diagnosis with not only prognostic but also public health implications for preserving kidney function.

Incidence and Clinical Impacts of COVID-19 Infection in Patients with Hemodialysis: Systematic Review and Meta-Analysis of 396,062 Hemodialysis Patients

Hemodialysis (HD) patients are highly susceptible to COVID-19 infection. However, comprehensive assessments of current evidence regarding COVID-19 in HD patients remain incomplete. We systematically searched PUBMED and EMBASE for articles published on incidence or mortality of COVID-19 infection in HD patients until September 2020. Two independent researchers extracted data and study-level risk of bias across studies. We conducted meta-analysis of proportions for incidence and mortality rate. Study heterogeneity and publication bias were assessed. A total of 29 articles with 3261 confirmed COVID-19 cases from a pool of 396,062 HD patients were identified. Incidence of COVID-19 in these HD patients was 7.7% (95% CI: 5.0-10.9%; study heterogeneity: I2 = 99.7%, p < 0.001; risk of publication bias, Egger's test, p < 0.001). Overall mortality rate was 22.4% (95% CI: 17.9-27.1%; study heterogeneity: I2 = 87.1%, p < 0.001; risk of publication bias, Egger's test: p = 0.197) in HD patients with COVID-19. Reported estimates were higher in non-Asian than Asian countries. Quality of study may affect the reported incidence but not the mortality among studies. Both incidence and mortality of COVID-19 infection were higher in HD patients. Available data may underestimate the real incidence of infection. International collaboration and standardized reporting of epidemiological data should be needed for further studies.

Vitamin D deficiency, cardiothoracic ratio, and long-term mortality in hemodialysis patients

Hemodialysis patients are a special group of patients with higher mortality rates. Hemodialysis patients with vitamin D deficiency {plasma levels of 25-hydroxyvitamin D [25(OH)D] below 20 ng/mL} are associated with even higher mortality rates. The prognostic importance of vitamin D deficiency in hemodialysis patients with different cardiothoracic ratios (CTRs) is still unclear. This prospective study was performed in a single hemodialysis center, and 186 patients were included. This study analyzed the prognostic importance of vitamin D deficiency in hemodialysis patients with different CTRs. Vitamin D deficiency patients had a significantly higher prevalence of stroke and diabetic mellitus than those without vitamin D deficiency. In addition, the CTR was higher in patients with vitamin D deficiency than in those without vitamin D deficiency. After multivariate logistic regression, we found that CTR was the solitary factor that was independently significantly associated with vitamin D deficiency [odds ratio: 1.07, 95% confidence internal (CI): 1.01–1.13, p = 0.02]. Additionally, vitamin D deficiency was associated with all-cause mortality in patients with higher CTR after adjustment in hierarchical regression models. In conclusion, we reported that vitamin D deficiency was independently significantly associated with a higher CTR. We additionally revealed that vitamin D deficiency was an independent predicator for all-cause mortality in higher CTR hemodialysis patients.

Gut Microbiota as Diagnostic Tools for Mirroring Disease Progression and Circulating Nephrotoxin Levels in Chronic Kidney Disease: Discovery and Validation Study

The interplay of the gut microbes with gut-producing nephrotoxins and the renal progression remains unclear in large human cohort. Significant compositional and functional differences in the intestinal microbiota (by 16S rRNA gene sequencing) were noted among 30 controls and 92 (31 mild, 30 moderate and 31 advanced) patients at different chronic kidney disease (CKD) stages (discovery cohort). A core CKD-associated microbiota consisted of 7 genera (Escherichia_Shigella, Dialister, Lachnospiraceae_ND3007_group, Pseudobutyrivibrio, Roseburia, Paraprevotella and Ruminiclostridium) and 2 species (Collinsella stercoris and Bacteroides eggerthii) were identified to be highly correlated with the stages of CKD. Paraprevotella, Pseudobutyrivibrio and Collinsella stercoris were superior in discriminating CKD from the controls than the use of urine protein/creatinine ratio, even at early-stage of disease. The performance was further confirmed in a validation cohort comprising 22 controls and 76 peritoneal dialysis patients. Bacterial genera highly correlated with indoxyl sulfate and p-cresyl sulfate levels were identified. Prediction of the functional capabilities of microbial communities showed that microbial genes related to the metabolism of aromatic amino acids (phenylalanine, tyrosine, and tryptophan) were differentially enriched among the control and different CKD stages. Collectively, our results provide solid human evidence of the impact of gut-metabolite-kidney axis on the severity of chronic kidney disease and highlight a usefulness of specific gut microorganisms as possible disease differentiate marker of this global health burden.

The association between chronic musculoskeletal pain and clinical outcome in chronic kidney disease patients: a prospective cohort study

Background and objectives: Chronic musculoskeletal (MS) pain is common in chronic kidney disease (CKD) patients. The association of chronic MS pain and CKD progression has not yet been established.

Method: We conducted a prospective cohort study to evaluate the association of chronic MS pain and CKD progression of pre-dialysis CKD patients.

Result: A total of 53.2% of pre-dialysis CKD patients had chronic MS pain. Patients classified as progression and non-progression had a similar prevalence of chronic MS pain at baseline, and similar baseline use of NSAIDs and Chinese herbal medicines. Univariate Cox analysis indicated that chronic MS pain and baseline NSAID or Chinese herbal medicine use were not significantly associated with progression of CKD. But multivariate Cox regression found chronic MS pain was independently significantly associated with all-cause mortality (HR, 2.912, 95% CI, 1.004–8.444; p = .049). However, serum levels of hs-CRP were similar between those chronic MS pain patients and without chronic MS pain patients (4.96 ± 9.4 vs. 4.25 ± 13.3 mg/L, p = .535).

Conclusion: The CKD patients with chronic MS pain was independently and significantly associated with all-cause mortality, but not independently and significantly associated with CKD progression and composite endpoints. The inflammatory marker-hs-CRP was similar between CKD patients with and without chronic MS pain.

Correlation between spot and 24h proteinuria: Derivation and validation of equation to estimate daily proteinuria

Daily urine protein (UP) loss is a cumbersome but important measurement to guide diagnosis and treatment of renal disease. Spot urine protein-creatinine ratio (UPCR) can been applied to estimate daily proteinuria. However, the correlations between spot and 24h proteinuria remain controversial. In this cross-sectional study, simultaneous collection of 24h and spot urines were performed from 1,039 (derivation cohort) and 204 CKD patients (validation cohort) of Chang Gung Memorial Hospital, from 2007 to 2017. The correlations between spot UPCR and 24h proteinuria were compared. The mean age of patients of derivation and validation cohort was 63 and 55 years and the mean estimated glomerular filtration rate was 62 ± 35 and 59 ± 36 mL/min/m², respectively. The correlation coefficient was 0.819 between UPCR and 24hUP. Prediction equation was derived as: Log₁₀24hUP (g) = 0.814 x Log₁₀UPCR (mg/mg) + 0.110 x Gender– 0.004 x Age + 0.004 x Body weight (kg) + 0.002 x CKD stage coefficient– 0.018, where CKD stage coefficient: CKD stage G1 = 1, G2 = 2, G3a = 3.1, G3b = 3.2, G4 = 4, G5 = 5. Correlation coefficient between measured and predicted 24hUP among derivation group and validation group is 0.866 and 0.915, respectively. However, the agreement of spot and daily estimates was less pronounced with proteinuria > 3g than lower values in Bland-Altman analysis. Spot UPCR can accurately predict 24hUP in patients with daily proteinuria below 3g. The development of this equation may facilitate estimation of 24hUP in the clinical practice.

Vitamin D deficiency in northern Taiwan: a community-based cohort study

Background

Vitamin D deficiency has become an important public health problem, however few studies have been conducted in subtropical countries, and the predictors of vitamin D deficiency in people with healthy renal function are unclear. The objective of this study was to evaluate the prevalence and factors associated with vitamin D deficiency in northern Taiwan.

Methods

The cross-sectional study was performed between August 2013 and August 2017, and included 3954 participants without chronic kidney disease (CKD) aged ≥30 years in northern Taiwan. Serum 25-hydroxyvitamin D [25(OH)-D] levels, biochemistry, sociodemographic variables (age, sex, education, occupation) and lifestyle habits (tea, coffee consumption and physical activities) were recorded. Associations between vitamin D status and these variables were examined using a regression model. The definition of deficiency was defined as a serum 25(OH)-D level < 20 ng/mL (50 nmol/L).

Results

The mean 25(OH)-D concentration was 28.9 ng/mL, and 22.4% of the study population had vitamin D deficiency. There was a significantly higher vitamin D deficiency ratio in the women compared to the men (22.9% vs 9.9%, p < 0.001). Vitamin D deficiency was most prevalent (38.4%) in those aged 30–39 years. Those with a graduate degree had the highest rate of vitamin D deficiency (31.5%). The predictors of vitamin D deficiency included female sex, young age, high education level, living in an urban area and physical inactivity. Tea consumption was negatively associated with vitamin D deficiency.

Conclusions

Vitamin D deficiency is prevalent in subtropical areas such as northern Taiwan in healthy individuals without CKD.

Multidisciplinary predialysis education reduces incidence of peritonitis and subsequent death in peritoneal dialysis patients: 5-year cohort study

Background

Technique failure secondary to peritonitis is a grave impediment to remain in peritoneal dialysis (PD) therapy leading to high mortality. Multidisciplinary predialysis education (MPE) has shown improvement in outcomes of chronic kidney disease (CKD) patients. However, the legacy effects of MPE in PD patients remain unclear.

Methods

All patients who started PD at single hospital in 2007–16 were enrolled. The incidences of peritonitis and peritonitis-related mortality were compared between MPE recipients and non-recipients. The content of the MPE was standardized in accordance with the NKF/DOQI guidelines. Kaplan-Meier analysis and Cox proportional hazards model were applied to identify the prognostic factors associated with peritonitis-free survival.

Results

Of 398 PD patients, 169 patients had received MPE before starting PD. The patients of MPE group had a lower peritonitis rate [median (IQR) 0 (0.29) versus 0.11 (0.69) episodes/person-year, P< 0.001] and a lower percentage of peritonitis-related deaths (3.6% versus 8.7%, P = 0.04) compared with the non-MPE group. The median time to the first episode of peritonitis in the non-MPE and MPE groups was 33.9 months and 46.7 months, respectively (Cox-Mantel log rank test, P = 0.003). Cox regression analysis revealed that MPE assignment (HR: 0.594; 95% CI: 0.434–0.813, P< 0.001) were significant independent predictors for peritonitis-free survival.

Conclusions

An efficient standardized MPE program may prolong the time to the first episode of peritonitis and reduce peritonitis rate, independent of age, gender, diabetes, hypertension, educational status and PD modality. Subsequently, decreased peritonitis-related death.

Lower risk of musculoskeletal pain among patients with end-stage renal disease treated by hemodialysis: A frequency-matched retrospective cohort study

Musculoskeletal pain is experienced by 5%-14% of the general adult population, and it is highly common among patients with chronic kidney disease (CKD). Therefore, the purpose of the study was to decide the prevalent rate of musculoskeletal pain in end-stage renal disease (ESRD) patients and to analyze this relationship between myalgia and ESRD using clinical features and determinants.A total of 93,013 patients who received ESRD diagnoses during 2000 and 2010 and were followed up until December 31, 2011, were identified from the Longitudinal Health Insurance Database 2000 (LHID2000) of the National Health Research Institutes (NHRI); non-ESRD controls were also selected from the LHID2000.The results indicated that the risk of chronic musculoskeletal pain is significantly lower in the hemodialysis treated ESRD cohort (subhazard ratio = 0.52, P < .0001), despite of sex, age, or comorbidities. Older patients were discovered to be at lower risk of chronic musculoskeletal pain (subhazard ratio = 0.94, P = .0765), with those aged 40 to 64 years having the highest hazard ratios (subhazard ratio = 1.21, P < .0001), and the prevalence of chronic musculoskeletal pain in women was higher than that in men (vs female sex; subhazard ratio = 0.69, P < .0001). Kaplan-Meier analysis revealed a higher cumulative incidence of myalgia development in the non-ESRD cohort compared with the ESRD cohort (log-rank test, P < .001).Clinicians should assess the risk of chronic musculoskeletal pain in such patients and provide appropriate and timely support of hemodialysis.

Preparation of carotenoid extracts and nanoemulsions from Lycium barbarum L. and their effects on growth of HT-29 colon cancer cells

Lycium barbarum L., a traditional Chinese herb widely used in Asian countries, has been demonstrated to be protective against chronic diseases such as age-related macular degeneration. The objectives of this study were to determine the carotenoid content in L. barbarum by high-performance liquid chromatography-mass spectrometry, followed by preparation of a carotenoid nanoemulsion to evaluate the mechanism of inhibition on HT-29 colon cancer cells. The highest extraction yield of carotenoids was attained by employing a solvent system of hexane-ethanol-acetone (1:1:1, v/v/v). Nine carotenoids, including neoxanthin (4.47 μg g-1), all-trans-zeaxanthin and its cis-isomers (1666.3 μg g-1), all-trans-β-cryptoxanthin (51.69 μg g-1), all-trans-β-carotene and its cis-isomers (20.11 μg g-1), were separated within 45 min and quantified using a YMC C30 column and a gradient mobile phase of methanol-water (9:1, v/v) (A) and methylene chloride (B). A highly stable carotenoid nanoemulsion composed of CapryolTM 90, Transcutol®HP, Tween 80 and deionized water was prepared with a mean particle size of 15.1 nm. Characterization of zeaxanthin standard, blank nanoemulsion, carotenoid extract and carotenoid nanoemulsion by differential scanning calorimetry curves and Fourier transform infrared spectra revealed a good dispersion of zeaxanthin-dominated carotenoid extract with no significant chemical change after incorporation into nanoemulsion. The in vitro release kinetic study showed a higher release profile at pH 5.2 than at physiological pH 7.4, suggesting a rapid release of carotenoids in the acidic environment (pH 4.5-6.5) characteristic of tumors. Both the carotenoid nanoemulsion and the extract were effective at inhibiting growth of HT-29 colon cancer cells, with an IC50 of 4.5 and 4.9 μg ml-1, respectively. Also, both treatments could up-regulate p53 and p21 expression and down-regulate CDK2, CDK1, cyclin A and cyclin B expression and arrest the cell cycle at G2/M. The study may form a basis for further exploration of L. barbarum nanoemulsion in cancer treatment.

Multidisciplinary predialysis education reduced the inpatient and total medical costs of the first 6 months of dialysis in incident hemodialysis patients

Background

The multidisciplinary pre-dialysis education (MPE) retards renal progression, reduce incidence of dialysis and mortality of CKD patients. However, the financial benefit of this intervention on patients starting hemodialysis has not yet been evaluated in prospective and randomized trial.

Methods

We studied the medical expenditure and utilization incurred in the first 6 months of dialysis initiation in 425 incident hemodialysis patients who were randomized into MPE and non-MPE groups before reaching end-stage renal disease. The content of the MPE was standardized in accordance with the National Kidney Foundation Dialysis Outcomes Quality Initiative guidelines.

Results

The mean age of study patients was 63.8±13.2 years, and 221 (49.7%) of them were men. The mean serum creatinine level and estimated glomerular filtration rate was 6.1±4.0 mg/dL and 7.6±2.9 mL⋅min⁻¹⋅1.73 m⁻², respectively, at dialysis initiation. MPE patients tended to have lower total medical cost in the first 6 months after hemodialysis initiation (9147.6±0.1 USD/patient vs. 11190.6±0.1 USD/patient, p = 0.003), fewer in numbers [0 (1) vs. 1 (2), p<0.001] and length of hospitalization [0 (15) vs. 8 (27) days, p<0.001], and also lower inpatient cost [0 (2617.4) vs. 1559,4 (5019.6) USD/patient, p<0.001] than non-MPE patients, principally owing to reduced cardiovascular hospitalization and vascular access–related surgeries. The decreased inpatient and total medical cost associated with MPE were independent of patients' demographic characteristics, concomitant disease, baseline biochemistry and use of double-lumen catheter at initiation of hemodialysis.

Conclusions

Participation of multidisciplinary education in pre-dialysis period was independently associated with reduction in the inpatient and total medical expenditures of the first 6 months post-dialysis owing to decreased inpatient service utilization secondary to cardiovascular causes and vascular access–related surgeries.

Trial Registration

ClinicalTrials.gov NCT00644046

Prescription of psychotropic drugs in patients with chronic renal failure on hemodialysis

OBJECTIVE

Patients on hemodialysis commonly have comorbid depression and require treatment with psychotropic drugs. This study aimed to investigate the prevalence of the use of psychotropic drugs among patients on hemodialysis and to elucidate the factors associated with use of each class of psychotropic medication.

METHODS

This cross-sectional study enrolled 195 hemodialysis patients with a mean age of 58.5 years. Patients were assessed using the Mini International Neuropsychiatric Interview, Hospital Anxiety and Depression Scale, Chalder Fatigue Scale and Short-form Health-related Quality of Life. We analyzed the frequency of psychiatric outpatient department visits within six months prior to interview and psychotropic drugs use within one month prior to interview, including antidepressants, antipsychotics, mood stabilizers, benzodiazepines (BZDs) and hypnotics.

RESULTS

Of the 195 patients, 47 (24.1%) fulfilled the DSM-IV criteria for major depressive disorder (MDD). Only 6.4% of patients diagnosed with MDD visited the psychiatry outpatient department within six months prior to interview. Of the total patients, the proportions with use of antidepressants, antipsychotics, mood stabilizers, BZDs and hypnotics were 5.6%, 1.0%, 3.1%, 42.6% and 20.0%, respectively. Having MDD was an independent factor associated with taking antidepressants (adjusted OR = 3.98, p = 0.036) and taking hypnotics (adjusted OR = 2.75, p = 0.011).

CONCLUSIONS

Depression is generally undetected or not well-managed among hemodialysis patients in the clinical setting. Only a small proportion of depressed patients received antidepressant treatment. BZDs and/or hypnotics might be exorbitantly prescribed. Clinicians should pay more attention to patients' emotional distress and provide appropriate treatment.

The association of uremic toxins and inflammation in hemodialysis patients

BACKGROUND

Cardiovascular disease is the leading cause of mortality in hemodialysis patients and is associated with chronic inflammation. Elevation of uremic toxins, particular protein-bound uremic toxins, is a possible cause of hyper-inflammation in hemodialysis patients. But the association between uremic toxins and inflammatory markers in hemodialysis is still unclear.

METHODS

We conducted a cross-sectional study to evaluate the association of the serum uremic toxins and inflammatory markers in hemodialysis patients.

RESULTS

The uremic toxins were not associated with inflammatory markers--including high sensitivity C-reactive protein, IL(Interleukin) -1β, IL-6, tumor necrosis factor-α. In multiple linear regression, serum levels of total p-cresol sulfate (PCS) were independently significantly associated with serum total indoxyl sulfate (IS) (standardized coefficient: 0.274, p<0.001), and co-morbidity of diabetes mellitus (DM) (standardized coefficient: 0.342, p<0.001) and coronary artery disease (CAD) (standardized coefficient: 0.128, p = 0.043). The serum total PCS levels in hemodialysis with co-morbidity of DM and CAD were significantly higher than those without co-morbidity of DM and CAD (34.10±23.44 vs. 16.36±13.06 mg/L, p<0.001). Serum levels of total IS was independently significantly associated with serum creatinine (standardized coefficient: 0.285, p<0.001), total PCS (standardized coefficient: 0.239, p = 0.001), and synthetic membrane dialysis (standardized coefficient: 0.139, p = 0.046).

CONCLUSION

The study showed that serum levels of total PCS and IS were not associated with pro-inflammatory markers in hemodialysis patients. Besides, serum levels of total PCS were independently positively significantly associated with co-morbidity of CAD and DM.

Factors associated with chronic musculoskeletal pain in patients with chronic kidney disease

Background

Chronic musculoskeletal (MS) pain is common in patients with chronic kidney disease (CKD) undergoing haemodialysis. However, epidemiological data for chronic MS pain and factors associated with chronic MS pain in patients with early- or late-stage CKD who are not undergoing dialysis are limited.

Method

A cross-sectional study to evaluate the prevalence of chronic MS pain and factors associated with chronic MS pain in patients with early- and late-stage CKD who were not undergoing dialysis, was conducted. In addition, the distribution of pain severity among patients with different stages of CKD was evaluated.

Results

Of the 456 CKD patients studied, 53.3% (n = 243/456) had chronic MS pain. Chronic MS pain was independently and significantly associated with hyperuricemia as co-morbidity, as well as with the calcium × phosphate product levels. In CKD patients with hyperuricemia, chronic MS pain showed a negative, independent significant association with diabetes mellitus as a co-morbidity (odds ratio: 0.413, p = 0.020). However, in the CKD patients without hyperuricemia as a co-morbidity, chronic MS pain showed an independent significant association with the calcium × phosphate product levels (odds ratio: 1.093, p = 0.027). Furthermore, stage-5 CKD patients seemed to experience more severe chronic MS pain than patients with other stages of CKD.

Conclusion

Chronic MS pain is common in CKD patients. Chronic MS pain was independently and significantly associated with hyperuricemia as co-morbidity, and with the calcium × phosphate product levels in early- and late-stage CKD patients who were not on dialysis.

Depression, 5HTTLPR and BDNF Val66Met polymorphisms, and plasma BDNF levels in hemodialysis patients with chronic renal failure

OBJECTIVE

Depression is the most prevalent comorbid psychiatric disease among hemodialysis patients with end-stage renal disease. This cross-sectional study investigated whether depression in hemodialysis patients is associated with the polymorphism of the 5' flanking transcriptional region (5-HTTLPR) of the serotonin transporter gene, the valine (Val)-to-methionine (Met) substitution at codon 66 (Val66Met) polymorphism of the brain-derived neurotrophic factor (BDNF) gene, or plasma BDNF levels.

METHODS

A total of 188 participants (mean age: 58.5±14.0 years; 89 men and 99 women) receiving hemodialysis at the Chang Gung Memorial Hospital were recruited. The diagnosis of major depressive disorder (MDD) was confirmed using the Chinese version of the Mini International Neuropsychiatric Interview. The genotypes of 5-HTTLPR and BDNF Val66Met were conducted using polymerase chain reactions plus restriction fragment length polymorphism analysis. The plasma BDNF levels were measured using an enzyme-linked immunosorbent assay kit.

RESULTS

Forty-five (23.9%) patients fulfilled the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-TR) criteria for a MDD. There were no significant effects of the 5-HTTLPR or BDNF Val66Met gene polymorphism on MDD among the hemodialysis patients. The plasma BDNF levels correlated significantly with age (P=0.003) and sex (P=0.047) but not with depression, the genotypes of 5-HTTLPR and BDNF Val66Met, the current antidepressant treatment, or the duration under hemodialysis.

CONCLUSION

Our results did not support the hypothesis of an involvement of the 5HTTLPR and BDNF Val66Met genotypes, or plasma BDNF levels in the pathogenesis of depression, in patients receiving hemodialysis. A study with a large sample size and homogenous patient group is warranted to confirm these findings.

Re-evaluating the predictive roles of metabolic complications and clinical outcome according to eGFR levels--a four-years prospective cohort study in Taiwan

Background

Metabolic complications are associated with clinical outcomes in patients with chronic kidney disease (CKD). These outcomes differ among patients according to the different stages of disease. The prevalence and association of type and number of metabolic complications with renal progression and death in patients having different eGFR levels has high clinical value, but this fact has been rarely evaluated in prospective studies.

Methods

We prospectively followed a cohort of 1157 CKD patients from 2006 to death or until 2010, and evaluated the prevalence of CKD-related complications and their association with renal progression (defined as a decline in eGFR by > 50% from baseline, or end-stage renal disease requiring dialysis) and death in patients with eGFRs above and below 45 mL/min/1.73 m² using Cox-proportional hazard models.

Results

The estimated rate (per 100 patient-years) of renal progression and death were 11.9 and 4.9, respectively. The eGFR thresholds determined by ROC analysis with a sensitivity of 90% for any metabolic complication were 60.8 mL/min/1.73 m² and 74.3 mL/min/1.73 m² using the MDRD and CKD Epidemiology Collaboration equations, respectively. CKD-related complications associated with renal progression in patients having eGFR < 45 mL/min/1.73 m² were hyperphosphatemia, anemia, microinflammation and hypoalbuminemia. Those CKD-related complications associated with death were hypoalbuminemia and hyperuricemia. Hypoalbuminemia predicted renal progression, and, hypoalbuminemia and microinflammation predicted death in patients with eGFR ≥ 45 mL/min/1.73 m². The number of complications (≥ 3) independently predicted both endpoints in patients with eGFR < 45 mL/min/1.73 m².

Conclusions

Hypoalbuminemia was a unique and strong predictor of renal progression and all-cause mortality in CKD patients, independent of their demographic characteristics, traditional risk factors, renal function severity, the presence of cardiovascular disease and other metabolic abnormalities. Most other metabolic complications and the number of complications (≥3) were associated with the clinical outcomes of patients with eGFR < 45 mL/min/1.73 m² rather than in those with higher eGFRs. The findings from the present study offer a novel insight into the association between metabolic complications and patient outcomes and may help to refine risk stratification according to disease stage.

The relationship between psychological factors, inflammation, and nutrition in patients with chronic renal failure undergoing hemodialysis

OBJECTIVE

Hemodialysis has an adverse impact on the immunological, nutritional, and emotional status of patients. The biochemical markers of inflammation and nutrition were studied as well as the relationship of these factors to emotional symptoms.

METHOD

One hundred and ninety-five patients undergoing hemodialysis were enrolled. The mean age was 58.5 years. Emotional symptoms were assessed using the Mini International Neuropsychiatric Interview, Hospital Anxiety and Depression Scale, Chalder Fatigue Scale, and Short-form Health-related Quality of Life. Venus blood was collected for laboratory assessment of serum hemoglobin, albumin, ferritin, C-reactive protein, interleukin (IL) 1beta), IL-6, and tumor necrosis factor alpha.

RESULTS

Among the 195 subjects (92 men and 103 women), 47 (24.1%) fulfilled the criteria for a major depressive disorder (MDD). The IL-6 level in patients with a MDD was significantly higher than in the patients without a MDD. Significant correlation was observed among the following factors: IL-6, fatigue, and quality of life for both physical and mental components. The albumin levels showed a significant correlation with the IL-6 and depression scores.

CONCLUSIONS

These results show that the serum levels of albumin and IL-6 might be laboratory markers associated with the expression of emotional symptoms in patients undergoing hemodialysis. Prospective studies are needed to determine the causal relationships among these variables.

Aliskiren reduced renal fibrosis in mice with chronic ischemic kidney injury--beyond the direct renin inhibition

Chronic renal ischemia leads to renal fibrosis and atrophy. Activation of the renin-angiotensin-aldosterone system is one of the main mechanisms driving chronic renal ischemic injury. The aim of the present study was to define the effect of aliskiren in chronic ischemia of the kidney. Two-kidney, one-clip mice were used to study chronic renal ischemia. Aliskiren significantly lowered the blood pressure in mice with renal artery constriction (92.1±1.1 vs. 81.0±1.8 mm Hg, P<0.05). Renin expression was significantly increased in ischemic kidneys when treated with aliskiren. In addition, (Pro)renin receptor expression was decreased by aliskiren in ischemic kidneys. Aliskiren treatment significantly increased klotho expression and reduced the expression of fibrogenic cystokines, caspase-3 and Bax in ischemic kidneys. Histological examination revealed that aliskiren significantly reduced the nephrosclerosis score (4.5±1.9 vs. 7.3±0.4, P<0.05). Immunofluorescence staining also showed that aliskiren decreased the deposition of interstitial collagen I in ischemic kidneys. In conclusion, direct renin inhibition significantly reduced renal fibrosis and apoptosis following chronic renal ischemia.

Association between cold dialysis and cardiovascular survival in hemodialysis patients

BACKGROUND

Higher cardiovascular mortality has been noted in patients with chronic kidney disease (CKD). CKD patients are also known to have impaired energy expenditure but the role of energy expenditure in cardiovascular disease is not yet known. Furthermore, the association between cold dialysis (CD) and clinical outcomes in hemodialysis patients is unclear.

METHODS

This was a single-center retrospective cohort study consisting of two groups: a CD group with dialyzate temperature <35.5 °C and a standard dialysis (SD) group with dialyzate temperature between 35.5 and 37 °C. The end points of the study were overall mortality, cardiac mortality and non-cardiac mortality. The study analyzed the associations between dialyzate temperature and long-term survival in CD and SD groups. Propensity score analysis was used to control for intergroup baseline differences.

RESULTS

Baseline characteristics of both groups were similar. Kaplan-Meier analysis showed that CD was significantly associated with a lower risk for overall mortality (P = 0.006) and cardiac mortality (P = 0.023) but not for non-cardiac mortality or infectious mortality. After multivariate Cox regression analysis, adjusting for propensity scores and other possible confounding factors, CD remained a significant beneficial factor for overall mortality (P = 0.030) and cardiac mortality (P = 0.034).

CONCLUSION

Our studies show that CD is significantly and independently associated with a lower risk for overall mortality and cardiac mortality.

Serum free p-cresyl sulfate levels predict cardiovascular and all-cause mortality in elderly hemodialysis patients--a prospective cohort study

BACKGROUND

The mortality rate of elderly hemodialysis (HD) patients is high. Serum p-cresyl sulfate (PCS) and indoxyl sulfate (IS) are associated with cardiovascular (CV) disease and mortality in renal patients. The association between such biomarkers and mortality in elderly HD patients has a high clinical value but remains unclear.

METHODS

This prospective cohort study investigated the association of serum IS and PCS with all-cause and CV mortality in elderly HD patients. Multivariate Cox regression analysis was used to estimate the risk of all-cause and CV mortality in this prospective cohort.

RESULTS

Of 112 patients, 45 deaths (18 CV deaths) were identified after a mean follow-up of 33.2 months. The cumulative and CV survival of patients with lower free PCS was significantly better than high free PCS patients. In multivariate Cox regression analysis, serum free PCS was associated with all-cause and CV mortality after various adjustments, including age, gender and diabetes status (Model 1), albumin (Model 2), Ca × P product and intact parathyroid hormone (Model 3), hemoglobin and high-sensitivity C-reactive protein (Model 4) and hierarchically selected covariates (age, diabetes status and albumin, Model 5).

CONCLUSION

Serum free PCS levels may help in predicting risk of all-cause and CV mortality in elderly HD patients beyond traditional and uremia related risk factors.

Depression and suicide risk in hemodialysis patients with chronic renal failure

BACKGROUND

Depression and suicide are well established as prevalent mental health problems for patients on hemodialysis.

OBJECTIVE

The authors examined the demographic and psychological factors associated with depression among hemodialysis patients and elucidated the relationships between depression, anxiety, fatigue, poor health-related quality of life, and increased suicide risk.

METHOD

This cross-sectional study enrolled 200 end-stage renal disease patients age ≥18 years on hemodialysis. Psychological characteristics were assessed with the Mini-International Neuropsychiatric Interview, the Hospital Anxiety and Depression Scale, the short-form Health-Related Quality of Life Scale, and Chalder Fatigue Scale, and structural equation modeling was used to analyze the models and the strength of relationships between variables and suicidal ideation.

RESULTS

Of the 200 patients, 70 (35.0%) had depression symptoms, and 43 (21.5%) had had suicidal ideation in the previous month. Depression was significantly correlated with a low body mass index (BMI) and the number of comorbid physical illnesses. Depressed patients had greater levels of fatigue and anxiety, more common suicidal ideation, and poorer quality of life than nondepressed patients. Results revealed a significant direct effect for depression and anxiety on suicidal ideation.

CONCLUSION

Among hemodialysis patients, depression was associated with a low BMI and an increased number of comorbid physical illnesses. Depression and anxiety were robust indicators of suicidal ideation. A prospective study would prove helpful in determining whether early detection and early intervention of comorbid depression and anxiety among hemodialysis patients would reduce suicide risk.

p-Cresyl sulphate and indoxyl sulphate predict progression of chronic kidney disease

Background. Indoxyl sulphate (IS) and p-cresyl sulphate (PCS) are uraemic toxins that have similar protein binding, dialytic clearance and proinflammatory features. However, only a few prospective studies have evaluated possible associations between these two retained solutes and renal disease progression in chronic kidney disease (CKD) patients.

Methods. This prospective observational study evaluated independent associations between serum total IS and PCS with renal progression in a selected cohort of patients having different stages of CKD. Baseline PCS and IS were correlated with renal progression [defined as decrements in estimated glomerular filtration rate (eGFR) > 50% from baseline or progression to end-stage renal disease (ESRD)] and death during a follow-up period of 24 months.

Results. Of 268 patients, 35 (13.1%) had renal progression and 14 (5.2%) died after a mean follow-up of 21 ± 3 months. Univariate Cox regression analysis followed by multivariate analysis showed that high-serum PCS levels were associated with renal progression and all-cause mortality independent of age, gender, diabetes status, albumin levels, serum IS, serum creatinine, Ca × P product, intact parathyroid hormone, haemoglobin or high-sensitivity C-reactive protein level. Serum IS was only associated with renal progression; however, the predictive power of serum IS was weakened when serum PCS was also present in the analytical model.

Conclusions. In addition to traditional and uraemia-related risk factors such as renal function, serum IS and PCS levels may help in predicting the risk of renal progression in patients having different stages of CKD.

Ventricular function and all-cause mortality in chronic kidney disease patients with angiographic coronary artery disease

BACKGROUND

Coronary artery disease (CAD) and chronic kidney disease (CKD) lead to high morbidity and mortality rates. Traditional and nontraditional risk factors, hypertension, fluid overloading and anemia can lead to myocardial ischemia, chamber hypertrophy and dilatation, and low left ventricular ejection fraction (LVEF) in CKD patients. The angiographic feature, ventriculographic LVEF and its relationship to all-cause mortality are unclear in patients with different stages of CKD who are not yet on dialysis.

METHODS

This retrospective study involved 980 CKD patients with suspected myocardial ischemia who underwent coronary angiography from 1995 to 2004. Demographic, clinical data and ventriculographic LVEF were assessed. Risk estimations for mortality were performed using Cox proportional hazard regression models.

RESULTS

Of the CKD patients, 445 (45.4%) had angiographic CAD. Their hemoglobin, body mass index (BMI) and LVEF values decreased with decrease in eGFR. Using Cox proportional hazard regression analysis, low LVEF was independently associated with CKD after adjustment for age, sex, diabetes, hypertension, BMI, hemoglobin and the presence of CAD. Significant independent prognostic factors for mortality included diabetes (hazard ratio [HR] = 2.946; 95% confidence interval [95% CI], 1.185-7.322), BMI (HR=0.864; 95% CI, 0.757-0.985), hemoglobin (HR=0.742; 95% CI, 0.594-0.928) and LVEF (HR=0.944; 95% CI, 0.918-0.970). Low LVEF was the only independent significant prognostic factor in CKD patients with angiographic CAD (HR=0.957; 95% CI, 0.918-0.996).

CONCLUSION

LVEF reduction was independently associated with CKD. Low LVEF was an independent predictor of mortality in CKD patients regardless of the presence of angiographic CAD.

The effects of arecoline on the release of cytokines using cultured peripheral blood mononuclear cells from patients with oral mucous diseases

In Taiwan there is a significant correlation between oral precancer diseases and oral cancer associated with the betel quid chewing habit. The carcinogenic components of betel quid are arecoline, arecaidine and safrole. However, it is unknown whether these substances influence the immune functions. This study investigated the effects of betel quid on the immune system using cultured peripheral blood mononuclear cells from patients with oral mucous diseases. In our experiment, mononuclear cells from 10 normal persons, 12 patients with precancer lesions, and 16 patients with squamous cell carcinoma were separated from blood samples and cultured. After stimulation by arecoline, the amounts of IL-2, TNF-alpha, TGF-beta and IFN-gamma secreted by mononuclear cells were measured using the ELISA method. The results showed that IL-2, TNF-alpha, and TGF-beta were significantly lower in mononuclear cells of normal persons as stimulated by arecoline. The TGF-beta amount in cells from oral submucous fibrosis patients with betel quid chewing habit (OSF-B) was lower than normal persons or patients who had long term betel quid chewing habit but were without oral mucosal diseases (N-B), and was also lower than the squamous cell carcinoma with betel quid chewing group (SCC-B). TNF-alpha was significantly lower in the squamous cell carcinoma with long term betel quid chewing group (SCC-B) than in normal persons. TNF-alpha was significantly higher in the squamous cell carcinoma without betel quid chewing group (SCC-N) than in normal persons and SCC-B groups. In addition, IFN-gamma was significantly lower in patients who had long term betel quid chewing but were without oral mucous lesions than the normal person and the OSF group. The results proved that betel quid influences cytokines production by mononuclear cells.

Ectopic expression of negative ARNT2 factor disrupts fish development

ARNT factors are a cluster of bHLH-PAS factors that heterodimerize with other specific bHLH-PAS factors to mediate a wide range of biological responses. Previously, we obtained a truncated form of ARNT2-like factor, ARNT2A, from zebrafish, which encompasses the basic-helix-loop-helix and PAS A/B domains, but lacks a transactivation domain at its carboxyl end. Herein, we report another truncated ARNT2-like factor, ARNT2X, in zebrafish, which differs from ARNT2A at its N-terminal region. In cultured ZLE cells, transiently expressed ARNT2X and ARNT2A inhibited 2,3,7,8-TCDD-activated cyp1a1 transcription with different efficiencies. In the developing embryo, arnt2X mRNA was consistently expressed in the retinal and neural tube regions until the hatching stages, but it exhibited a more specific pattern at larval stages, including expression in the brain, eyes, hypothalamus, pharyngeal skeleton, heart, liver, pronephros duct, pectoral fin, and epithelial cells of the swim bladder. In contrast, arnt2A transcription diminished after hatching. Microinjecting a recombinant arnt2X-expression vector into fertilized eggs before cleavage stages caused severe defects in brain, eyes, pectoral fin, heart, and gut development. This suggests that the ARNT-mediated signal transduction pathways play important roles in fish tissue development.

Overexpression of a Zebrafish ARNT2-like Factor Represses CYP1A Transcription in ZLE Cells

Aryl hydrocarbon receptor nuclear translocator (ARNT) factors belong to a novel basic-helix-loop-helix-PAS (bHLH-PAS) transcription factor family that controls a variety of physiological and developmental processes. In a previous study, we obtained a partial complementary DNA fragment of an ARNT2-like factor from zebrafish embryo, liver, and other tissues by reverse transcription-polymerase chain reaction. In an effort to characterize the function of this factor, we screened an embryonic complementary DNA library and obtained a complete cDNA of this ARNT2-like factor, zARNT2A. The deduced protein sequence of zARNT2A encompasses the basic-helix-loop-helix and PAS-A/B motifs and shares highest sequence similarity with the amino-terminal half of mouse ARNT2 factor. However, it lacks a carboxy-terminal transactivation motif following the PAS-A/B motifs. Transient expression of zARNT2A in cultured cells resulted in repression of TCDD-dependent CYP1A transcription. Whole-mount in situ hybridization revealed that zARNT2A is expressed in brain and pronephros at prime-5 stages. In adult fish, zARNT2A messenger RNA is transcribed in a wide range of tissues, which indicates that zARNT2A and its corresponding signal transduction mechanisms have important roles in fish development and other physiological aspects.

Oct-6: a regulator of keratinocyte gene expression in stratified squamous epithelia

POU domain proteins have been implicated as regulators of differentiation and development, particularly in early embryogenesis and in neural morphogenesis. Given that neural and epidermal lineages originate from a common precursor (ectodermal) cell, we explored the possibility that POU proteins are involved in epidermal differentiation. Using reverse transcription-PCR and degenerate oligonucleotides, we generated several POU domain cDNAs from cultured human epidermal mRNAs. One of these encoded a sequence identical to the rodent Tst-1/SCIP/Oct-6 POU domain. Subsequently, we isolated a cDNA encoding a 45.3-kDa protein with 98% sequence identity to rat Tst-1/SCIP and 94% identity to mouse Oct-6. This protein bound specifically to the canonical octamer motif, warranting its designation as human Oct-6. By RNase protection assays, by PCR, and by immunoblot analysis, Oct-6 was expressed in cultured epidermal keratinocytes. By in situ hybridization, Oct-6 mRNA was detected not only in epidermis but also a variety of other stratified squamous epithelia and with greater signals than testis, the tissue in which this POU protein was originally discovered. Moreover, Oct-6 exerted a marked and specific negative influence on expression of the K5 and K14 genes, abundantly expressed in most dividing stratified squamous epithelial cells and downregulated as cells commit to terminally differentiate. The repressive effect was complex, but it was not observed with Oct-1, nor was it seen with a truncated Oct-6 missing the POU domain. Taken together, our studies suggest that Oct-6 may play an important role in controlling gene expression in stratified squamous epithelia, including epidermis.

[Incidence of tuberculosis in the hunting tribe E-Lun-Chun in Northeast China]

The E-Lun-Chun, or Ortochen, a national minority in North East China, consisted of 2,262 members in 1953. In the mid-17th century a Russian invasion had displaced them from their original home in southward direction over the Amur river towards the Sin An Lin mountain range. While coming into closer contact with neighbouring peoples, tuberculosis and other infectious diseases spread rapidly among the members of the tribe. Under the Japanese occupation (1932-1945) the incidence of pulmonary tuberculosis was estimated at about 30% of the inhabitants. After initiation of modern measures to fight disease (case finding, drug treatment, BCG vaccination) the incidence dropped from 12.8% in 1954 to 6.5% in 1985, representing a reduction by 49.2% in 31 years. In 1963 a tuberculosis hospital was set up exclusively for E-Lung-Chun and indigenous medical personnel was suitably trained. However, the expected success of drug therapy was hampered by the tribe's abuse of alcohol and their unsteady life as hunters. To achieve a more stable state of health among the E-Lun-Chun, information work and measures to fight tuberculosis should be intensified in future.

Characterization of genomic clones specifying rabbit alpha- and beta-ventricular myosin heavy chains

We have isolated gene sequences coding for the alpha- and beta-myosin heavy chains (HC) of rabbit ventricular muscle. A rabbit genomic library was screened with previously characterized cDNA clones specifying part of the light meromyosin and the entire subfragment 2 portion of alpha- and beta-myosin HCs, as well as with a clone containing the 3' nontranslated sequences of the alpha-myosin HC mRNA. Seven strongly hybridizing clones were analyzed in detail. One genomic clone encoded all of the 3' nontranslated sequences of an alpha-cDNA clone and, therefore, contained the 3' end of the alpha-myosin HC gene. Electron microscopic heteroduplex analysis and DNA sequence analysis showed that this clone overlapped a second genomic clone providing more than 25 kilobase pairs of the alpha-myosin HC gene. The exons within this region corresponded to approximately equal to 85% of the mRNA and were separated by at least 28 introns. A clone for the beta-myosin HC gene was also identified by Southern blot hybridization, by heteroduplex mapping, and by comparing the DNA sequence of a subfragment 2 exon to sequences of the alpha- and beta-cDNA clones. The introns of the alpha- and beta-myosin HC genes were in the same position but showed marked variation in length. These results conclusively showed that the alpha- and beta-myosin HCs are products of separate genes.

Cloned mRNA sequences for two types of embryonic myosin heavy chains from chick skeletal muscle. II. Expression during development using S1 nuclease mapping

We have examined the expression of two embryonic myosin HC mRNAs using two cDNA clones (110 and 251) which we have previously constructed from RNA isolated from 14-day-old embryonic chick skeletal muscle. Sequence divergence in the 3' nontranslated regions enabled us to analyze the differential expression of the mRNAs corresponding to the two clones using the S1 nuclease mapping procedure. Clone 251 mRNA is expressed primarily in embryonic fast muscle, where its transcripts appear to be the predominant species. This mRNA is minimally expressed in the posthatching period, but it is not detected in adult leg and breast muscle. Messenger RNA for clone 110 is also primarily expressed in embryonic fast muscle. However, in the posthatching and adult stages of development, it continues to be expressed at a low level in leg muscle but not in breast muscle. The differential expression of these mRNAs during development strongly indicates that they correspond to two different genes coding for embryonic myosin HCs. Other myosin HC mRNAs which were partially homologous to the clone 110 or 251 mRNAs were also identified by S1 nuclease mapping. Using the probes from these two clones, a minimum of four other developmentally expressed forms were detected. Two of these correspond to "neonatal" myosin HCs, while the other two code for different adult myosin HCs present in leg and in breast muscle, respectively. The results therefore suggest a much greater diversity of myosin HC mRNAs expressed during development than previously reported.

Molecular cloning of mRNA sequences for cardiac alpha- and beta-form myosin heavy chains: expression in ventricles of normal, hypothyroid, and thyrotoxic rabbits

We have isolated cDNA clones from thyrotoxic (pMHC alpha) and normal (pMHC beta) adult rabbit hearts. Restriction map analysis and DNA sequence analyses show that, although there is strong homology between overlapping regions of the two clones, they are distinctly different. The two clones exhibited 78-83% homology between the derived amino acid sequences and those determined by direct amino acid sequence analysis of rabbit fast skeletal muscle myosin heavy chains. The clones specify a segment of the myosin heavy chain corresponding to subfragment 2 and the COOH-terminal portions of subfragment 1. Nuclease S1 mapping was used to compare transcription of the two clones with expression of the alpha and beta forms of myosin heavy chains in the ventricles of thyrotoxic, hypothyroid (propylthiouracil-treated), and normal rabbits. Thyrotoxic ventricles contained only pMHC alpha transcripts whereas hypothyroid ventricles contained exclusively pMHC beta transcripts. These data correlate well with the presence of alpha- and beta-form myosin heavy chains. In the normal young adult rabbit, pMHC beta transcripts predominate, agreeing with the known beta form/alpha form ratio of 4:1. We therefore conclude that pMHC alpha and pMHC beta contain sequences of the alpha- and beta-form myosin heavy chain genes, respectively.

Molecular cloning of two fast myosin heavy chain cDNAs from chicken embryo skeletal muscle

Recombinant DNA clones containing sequences for two different types of myosin heavy chain (HC) genes from chicken embryonic skeletal muscle were constructed and analyzed. Specificity of the clones for myosin HC was demonstrated by hybrid-arrested translation, by hybridization to a 7.0-kb mRNA, and by comparison of DNA sequences with known amino acid sequences of rabbit skeletal muscle myosin HC. Restriction enzyme and electron-microscopic heteroduplex analysis showed the presence of two distinct but homologous cDNA sequences. Hybrid melting curves indicated that both types of sequences represent fast myosin HC sequences.

Restriction endonuclease analysis of mitochondrial DNA from grande and genetically characterized cytoplasmic petite clones of Saccharomyces cerevisiae

Digestion of grande mitochondrial DNA (mtDNA) BY EcoRI restriction endonuclease gives rise to nine fragments with a total molecular weight of 51.8 x 10(6). HindIII digestion yields six fragments with a similar total molecular weight. Specific restriction fragments can be detected despite the fact that yeast mtDNA consists of a heterogeneous distribution of randomly broken molecules. Digestion patterns of 10 genetically characterized petite clones containing various combinations of five antiobiotic resistance markers indicate that the petite mtDNA predominantly represents deletion of the grande genome. The petite mtDNAs contained up to seven EcoRI restriction fragments which comigrate with grande restriction fragments, and at least one fragment that did not correspond to any in the grande. Some strains contained multiple fragments with mobility different from that of grande; these fragments were usually present in less than molar concentrations. The genetic markers were associated with individual sets of restriction fragments. However, several internal inconsistencies prevent the construction of a definitive genetic fragment map. These anomalies, together with the digestion patterns, provide strong evidence that, in addition to single contiguous deletion, other changes such as multiple deletion and heterogeneity of mtDNA populations are present in some of the petite mtDNAs.