Beneficial and adverse effects of dam construction in canal tannery wastewater effluent with a high content of chromium in Hazaribagh, Bangladesh

BACKGROUND

Blockage to divide downstream canals into upstream canals, into which tannery wastewater including a high concentration of trivalent chromium [Cr(III)] is directly discharged, has been constructed in Hazaribagh, a tannery built-up area in Bangladesh. However, there has been no study to verify the environmental significance of blockage construction for water pollution of Cr in nature.

METHODS

Consecutive fixed area monitoring for a total of 164 water samples collected outside and inside Hazaribagh from 2014 to 2023 was carried out to clarify the effects of stagnant and flowable canal water in the presence or absence of blockage on Cr(III) and hexavalent Cr [Cr(VI)] concentrations.

RESULTS

Since pollution of Cr(III) and Cr(VI) in Buriganga River (outside Hazaribagh) was not serious, this study then focused on their pollution in canal water (inside Hazaribagh) in the nonblockage period, blockage construction period and blockage destruction period. As expected, the mean Cr(III) concentration in downstream canal water samples in the blockage construction period was more than 98% lower than that in the upstream canal water samples in the same period, while the concentrations were comparable in downstream and upstream canal water samples in the nonblockage period and blockage destruction period. Unexpectedly, the mean concentration of Cr(VI) in the upstream canal water samples in the blockage construction period was 38.6-fold and 3.3-fold higher than that in the downstream canal water samples and the Cr(VI) guideline value by the US-EPA, respectively.

CONCLUSION

This study demonstrated for the first time not only a merit of decreased Cr(III) pollution but also a demerit of increased Cr(VI) pollution in stagnant water derived from blockage construction in natural environments. This bitter lesson obtained by the enclosure of Cr(III)-polluted water is globally applicable for water pollution of Cr(III), which is used in various industries including the leather industry.

A Novel Approach for Designing a Sub-Bandgap in CuGa(S,Te)2 Thin Films Assisted with Numerical Simulation of Solar Cell Devices for Photovoltaic Application

As a well-explored chalcopyrite material, copper gallium sulfide CGS has been considered a potential material for solar cell absorber layers. However, its photovoltaic attributes still require to be improved. In this research, a novel chalcopyrite material, copper gallium sulfide telluride CGST, has been deposited and verified as a thin film absorber layer to fabricate high-efficiency solar cells by experimental testing and numerical simulations. The results display the intermediate band formation in CGST with incorporation of Fe ions. Electrical studies showed enhancement in mobility from 1.181 to 1.473 cm² V^-1 s^-1 and conductivity from 2.182 to 5.952 S cm^-1 for pure and 0.08 Fe-substituted thin films. The I-V curves display the photoresponse and ohmic nature of the deposited thin films, and the maximum photoresponsivity (0.109 A W^-1) was observed for 0.08 Fe-substituted films. Theoretical simulation of the prepared solar cells was carried out using SCAPS-1D software, and the obtained efficiency displayed an increasing trend from 6.14 to 11.07% as the Fe concentration increased from 0.0 to 0.08. This variation in efficiency is attributed to the decrease in bandgap (2.51-1.94 eV) and the formation of an intermediate band in CGST with Fe substitution, which is evidenced in UV-vis spectroscopy. The above revealed results open the way to 0.08 Fe-substituted CGST as a promising candidate as a thin film absorber layer in solar photovoltaic technology.

Unexpected associations of long-term and excessive exposure to trivalent chromium with hypertension and glycosuria in male tannery workers

Serious health hazards including renal, skin and hearing disorders have been reported in Bangladeshi tannery workers (TWs) who were chronically exposed to a large amount of trivalent chromium [Cr(III)]. However, the effects of Cr(III) exposure on the prevalence of hypertension and the prevalence of glycosuria in TWs remain unknown. Since the Cr level in toenails is an established marker reflecting long-term exposure to Cr(III) in humans, the associations of Cr levels in toenails with the prevalence of hypertension and the prevalence of glycosuria in male tannery and non-tannery office workers (non-TWs) in Bangladesh were investigated in this study. The mean toenail Cr level in non-TWs (0.5 μg/g, n = 49) was comparable to that in the general population reported previously. Mean Cr levels in TWs with a low toenail Cr level (5.7 μg/g, n = 39) and those with a high toenail Cr level (298.8 μg/g, n = 61) were >10-fold and >500-fold higher, respectively, than that in non-TWs. Our univariate and multivariate analyses indicated that the prevalence of hypertension and the prevalence of glycosuria in TWs with a high toenail Cr level, but not in TWs with a low toenail Cr level, were significantly lower than those in non-TWs. This study showed for the first time that long-term and excessive exposure to Cr(III) that is more than >500-fold but not >10-fold higher than the usual exposure level could decrease the prevalence of hypertension and the prevalence of glycosuria in TWs. Thus, this study revealed unexpected effects of exposure to Cr(III) on health.

Decreased hearing levels at frequencies for understanding speech in tannery workers exposed to a high level of trivalent chromium in Bangladesh

Hexavalent chromium [Cr(VI)], which has a strong corrosive effect, has been reported to cause perforation of the eardrum. Trivalent chromium [Cr(III)] also has a weak corrosive effect. However, there has been no study on the effects of exposure to Cr, either Cr(VI) or Cr(III), on hearing levels in animals or humans. In this study, the effect of Cr(III) exposure on hearing levels was determined in a human study. Then the reproducibility of the results obtained in the human study and the etiology were investigated in an animal study. The mean levels of total chromium (t-Cr) in hair and toenails from 100 Bangladeshi tannery workers were >20-fold and >360-fold higher, respectively, than those in hair and toenails from 49 Bangladeshi non-tannery workers (office workers). Multivariate analysis revealed decreases of hearing levels (DHLs) at 1 k and 4 k Hz, frequencies that are crucial for understanding language, but not at 8 k and 12 k Hz, in the tannery workers. Since >99.99% of t-Cr in the wastewater that the workers were in direct contact with in the tanneries was Cr(III), the epidemiological results suggest Cr(III)-mediated DHLs in the tannery workers. The results of animal experiments in this study further showed that treatment with eardrops but not intraperitoneal injection with the same amount of Cr(III) that tannery workers might be exposed to resulted in DHL with a damaged eardrum in mice. Previous studies suggested that Cr(III) can directly reach the eardrums of tannery workers via droplets in the air. Cr(III) could also reach the eardrum via picking an ear canal with a finger contaminated with tannery wastewater including Cr(III). Taken together, the results of both human and animal studies suggest the risk of DHLs caused by damage of the eardrum through external exposure to Cr(III) via the ear canal.

Redistribution of potentially toxic elements in the hydrosphere after the relocation of a group of tanneries

Simultaneous relocation of a group of pollutant sources in a heavily polluted area is a rare event. Such a relocation has been implemented in Hazaribagh, a tannery built-up area with heavy pollution, in Bangladesh. This provides a valuable opportunity to compare the changes in environmental conditions associated with the relocation of multiple putative sources. Our environmental monitoring for a period of 6 years at the stationary areas centered on Hazaribagh geographically revealed trivalent [Cr(III)], hexavalent [Cr(VI)] chromium, lead, iron, and manganese as tannery-related elements after the legal deadline for tannery relocation. The median Cr(III) level in canal water, into which wastewater from tanneries was directly discharged, after the relocation was 97% lower of that before the relocation, indicating a beneficial effect of the relocation. In contrast, the median Cr(VI) level in water samples just after the relocation and 2 years after the relocation were approximately 5-fold and 30-fold higher, respectively, than those before the relocation. These results indicate not only a harmful effect of the relocation but also the possibility of conversion from Cr(III) to Cr(VI) in nature. Although the health hazard indexes considering all of the tannery-related elements in all of the canal water samples before the relocation exceeded the safety thresholds, the percentages of samples in which the indexes exceeded their safety thresholds after the relocation decreased by 32.5%-45.0%. Treatment with our patented hydrotalcite-like compound consisting of magnesium and iron (MF-HT) resulted in decreases in the health hazard indexes in all of the water samples in which the indexes exceeded their safety thresholds to levels lower than their thresholds. Thus, this study shows the double-edged effects associated with the relocation and a potential solution.

Co-deposition of MoS2films by reactive sputtering and formation of tree-like structures

Transition metal dichalcogenides (TMDCs) are versatile layered materials with potential applications ranging from optoelectronic devices to water splitting. Top-down fabrication methods such as exfoliation are not practical for a large-scale production of high-quality devices: a bottom-up approach such as sputtering, a low-temperature deposition method, is more suitable. However, due to its anisotropic nature, the growth mechanism of molybdenum disulfide (MoS2) via sputtering is complex and remains to be investigated in detail. In this paper, we study the growth of MoS2 films co-deposited by using a sulfur (S) hot-lip cell and a molybdenum (Mo) sputtering target via reactive sputtering. The impact of S partial pressure on the structure and morphology of MoS2films was systematically characterized, and it was observed that the growth is dominated by vertically-oriented sheets with horizontal branches, resulting in a tree-like structure. The growth front of the structures is ascribed to the anisotropic incorporation of adatoms with regards to the orientation of MoS2.

Clinical spectrum and predictors of severity of dengue among children in 2019 outbreak: a multicenter hospital-based study in Bangladesh

BACKGROUND

The mosquito-borne arboviral disease dengue has become a global public health concern. However, very few studies have reported atypical clinical features of dengue among children. Because an understanding of various spectrums of presentation of dengue is necessary for timely diagnosis and management, we aimed to document the typical and atypical clinical features along with predictors of severity among children with dengue during the largest outbreak in Bangladesh in 2019.

METHODS

We conducted a cross-sectional study between August 15 and September 30, 2019. in eight tertiary level hospitals in Dhaka city. Children (aged < 15 years) with serologically confirmed dengue were conveniently selected for data collection through a structured questionnaire. Descriptive, inferential statistics, and multivariable logistic regression were used to analyze data.

RESULTS

Among the 190 children (mean age 8.8 years, and male-female ratio 1.22:1) included in the analysis, respectively 71.1 and 28.9% children had non-severe and severe dengue. All children had fever with an average temperature of 103.3 ± 1.2 F (SD). Gastrointestinal symptoms were the most common associated feature, including mostly vomiting (80.4%), decreased appetite (79.5%), constipation (72.7%), and abdominal pain (64.9%). Mouth sore, a less reported feature besides constipation, was present in 28.3% of children. Atypical clinical features were mostly neurological, with confusion (21.3%) being the predominant symptom. Frequent laboratory abnormalities were thrombocytopenia (87.2%), leucopenia (40.4%), and increased hematocrit (13.4%). Age (AOR 0.86, 95%CI 0.75-0.98, p = 0.023), mouth sore (AOR 2.69, 95%CI 1.06-6.96, p = 0.038) and a decreased platelet count (< 50,000/mm3) with increased hematocrit (> 20%) (AOR 4.94, 95%CI 1.48-17.31, p = 0.01) were significant predictors of severity.

CONCLUSIONS

Dengue in children was characterized by a high severity, predominance of gastrointestinal symptoms, and atypical neurological presentations. Younger age, mouth sores, and a decreased platelet with increased hematocrit were significant predictors of severity. Our findings would contribute to the clinical management of dengue in children.

Development of an efficient remediation system with a low cost after identification of water pollutants including phenolic compounds in a tannery built-up area in Bangladesh

Water pollution caused by tannery wastewater is an important issue in developing countries. Most studies have focused on inorganic chemicals represented by chromium as a tannery-related main pollutant. This is the first study in which pollution of water by tannery-related organic chemicals was assessed by a combination of qualitative and quantitative analyses. Our quantitative analysis showed that the maximum concentration of total phenolic compounds (phenols), consisting of phenol, bisphenol F, p-cresol and chlorocresol, in canal water in a tannery built-up area in Bangladesh was >67-fold higher than the Environmental, Health and Safety (EHS) guideline value. Mapping of our results indicated tanneries as the sources of phenols pollution. Our original depurative, a hydrotalcite-like compound consisting of magnesium and iron (MF-HT), could adsorb all kinds of phenols and exhibited the highest phenol adsorption ability (115.8 mg/g) among reported hydrotalcite-like compounds. The levels of phenols in canal water samples were reduced to levels below the guideline value by using MF-HT with assistance of a photocatalytic reaction. Moreover, the mean level of chromium (112.2 mg/L) in canal water samples was decreased by 99.7% by using the depurative. Thus, the depurative has the potential for solving the problem of tannery-related water pollution by phenols and chromium.

Increased levels of renal damage biomarkers caused by excess exposure to trivalent chromium in workers in tanneries

BACKGROUND

The process for leather material production is carried out in developing countries using a large amount of trivalent chromium [Cr(III)]. Assesment of health risks for millions of workers in tanneries worldwide that are highly polluted with Cr(III) is needed.

METHODS

Levels of total Cr and its chemical species in wastewater samples from tannery built-up areas of Bangladesh were investigated. Cr-mediated renal damage was assessed in 100 male tannery workers by epidemiological analysis consisting of questionnaires and measurements of levels of urinary Cr and urinary renal damage markers [urinary levels of total protein and kidney injury molecule-1 (KIM-1)].

RESULTS

High levels of total Cr (mean ± standard deviation = 1,908,762 ± 703,450 μg/L) were detected in wastewater samples from 13 sites of tanneries. More than 99.99% of total Cr in the wastewater was Cr(III), indicating that workers in the tanneries were exposed to large concentrations of Cr(III). Cr levels (mean ± standard, 2.89 ± 4.23 μg/g creatinine) in urine samples from the workers in tanneries were >24-fold higher than the levels in a general population previously reported. Multivariate analysis showed significant correlations between urinary levels of Cr and urinary levels of renal damage biomarkers. Nagelkerke Pseudo R² values also showed that Cr level is the strongest contributor to the levels of renal damage biomarkers in the workers.

CONCLUSION

Our results newly suggest that excess exposure to Cr(III) could be a risk for renal damage in humans.

Human Uptake of Eggshell Powder as an Alternate Source of Calcium

Calcium (Ca) plays important structural and physiological roles in our body. Usually, our body meets up its Ca need from dietary sources. In developing countries like Bangladesh, most of the people cannot afford Carich foods. So, Ca supplements are generally prescribed to deficient individual that usually costs high. It is, therefore, necessary to find out an alternative and cheap source of Ca supplement especially in Bangladesh. Considering the above facts, the main focus of this study was to explore the possibility of using the egg shell as a source of Ca. In his study, discarded eggshells were collected, washed, decontaminated properly and ground to a fine powder. Washing with tap water followed by 10 min boiling completely decontaminated the eggshells. On an average 3.45, 5.91, 4.5 and 4.55 g of eggshell powder (ESP) per shell were obtained from a domesticated fowl, domestic duck, white leghorn, and rhode island red, respectively. Particle size was measured using scanning electron microscope and the size ranged between 3.47-5.94 μm. The Ca contents were found as 38.65, 35.0, 24.85 and 35.73 g in domesticated fowl, domestic duck, white leghorn, and rhode island red, respectively per 100 g of ESP. Taking daily Ca requirements into account, we observed that powder from almost half of an eggshell is sufficient to fulfill the daily Ca need. The amount of magnesium (Mg) in 100 g ESPs was found to be 45.37, 32.48, 45.17 and 45.27 mg and that of iron (Fe) was 35.07, 33.47, 31.91 and 33.06 mg in domesticated fowl, domestic duck, white leghorn, and rhode island red, respectively. Various toxic heavy metals such as chromium (Cr), lead (Pb) and arsenic (As) contents remained below the detection level in ESP samples. Organoleptic tests revealed that the ESP does not have any objectionable effects on the texture and flavor of ESP-fortified foods and juice. These results suggested that the ESP can be used as an alternative and important cheap source of Ca and other beneficial micronutrients for human being. However, it is necessary to create the awareness and public perception regarding the use of EPS Dhaka Univ. J. Pharm. Sci. 18(2): 249-255, 2019 (December)

Chromium-mediated hyperpigmentation of skin in male tannery workers in Bangladesh

Since tannery workers in developing countries are chronically exposed to high levels of chromium (Cr), there are serious concerns about health problems. However, there has been limited study in which Cr levels were measured in tannery workers, who are chronically exposed to Cr. Our preliminary inspection showed that there was hyperpigmented skin in tannery workers. We therefore investigated the correlation between skin pigmentation levels digitally evaluated as L* values by using a reflectance spectrophotometer and Cr levels in skin appendages in 100 male tannery workers and in 49 male non-tannery workers in Bangladesh. Digitalized skin pigmentation levels of the face and feet in addition to Cr levels in hair and toenails in tannery workers were significantly higher than those in non-tannery workers in our univariate analysis. Spearman's rank correlation coefficient analysis showed significant correlation between duration of tannery work (years) and Cr levels in hair (r = 0.62) and toenails (r = 0.61). Our multivariate analysis also showed that Cr levels in hair and toenails were significantly correlated with digitalized skin pigmentation levels of the face and feet in addition to duration of tannery work in all participants. Thus, our results showed the development of hyperpigmented skin in tannery workers. Our results also suggested that hyperpigmented skin could be a useful diagnostic marker for chronic exposure to Cr. Furthermore, cutaneous L* value might be a convenient marker for detection of chronic Cr poisoning, since the digitalized values enable objective evaluation of skin pigmented levels by general people as well as dermatologists.

Amelioration of arsenic-induced toxic effects in mice by dietary supplementation of Syzygium cumini leaf extract

Arsenic created a serious public health problem in Bangladesh due to its presence in groundwater and dissemination of the toxic effects to millions of people. The scarcity of the treatment options to manage this affected population has made the situation much worse. To find a promising treatment option, this study was undertaken to examine the ameliorating roles of Syzygium cumini leaf extract (SLE) against arsenic-induced toxic effects in mice. Swiss albino mice were divided into four groups where ‘control’ group received pure water + normal feed, ‘arsenic (As)’ group received sodium arsenite (NaAsO₂)-containing water (10 μg/g body weight/day) + normal feed, ‘As+SLE’ group received NaAsO₂-containing water + feed supplemented with SLE (50 µg/g body weight/day) and finally the ‘SLE’ group received pure water + feed supplemented with SLE. A gradual increase in body weight gain was observed in control mice; however, the body weight gain in As-exposed mice was decreased. This decrease in body weight gain was prevented in As+SLE group mice that received SLE supplemented feed. Arsenic showed a secondary effect by causing enlargement of spleen, kidney and liver of ‘As’ group mice and this enlargement of the organs was minimized with SLE supplementation. In addition, SLE abrogated arsenic-mediated elevation of serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), uric acid and glucose. These results, therefore, suggest that SLE might have future therapeutic value for preventing or reducing arsenic-induced toxic effects.

A rare variety of congenital adrenal hyperplasia with mosaic Klinefelter syndrome: a unique combination presenting with ambiguous genitalia and sexual precocity

Congenital adrenal hyperplasia (CAH) due to the three-beta-hydroxysteroid-dehydrogenase (3β-HSD) enzyme deficiency is a rare autosomal recessive disorder presenting with sexual precocity in a phenotypic male. Klinefelter syndrome (KS) is the most common sex chromosome aneuploidy presenting with hypergonadotropic hypogonadism in a male. However, only a handful of cases of mosaic KS have been described in the literature. The co-existence of mosaic KS with CAH due to 3β-HSD enzyme deficiency portrays a unique diagnostic paradox where features of gonadal androgen deficiency are masked by simultaneous adrenal androgen excess. Here, we report a 7-year-old phenotypic male boy who, at birth presented with ambiguous genitalia, probably a microphallus with penoscrotal hypospadias. Later on, he developed accelerated growth with advanced bone age, premature pubarche, phallic enlargement and hyperpigmentation. Biochemically, the patient was proven to have CAH due to 3β-HSD deficiency. However, the co-existence of bilateral cryptorchidism made us to consider the possibility of hypogonadism as well, and it was further explained by concurrent existence of mosaic KS (47,XXY/46,XX). He was started on glucocorticoid and mineralocorticoid replacement and underwent right-sided orchidopexy on a later date. He showed significant clinical and biochemical improvement on subsequent follow-up. However, the declining value of serum testosterone was accompanied by rising level of FSH thereby unmasking hypergonadotropic hypogonadism due to mosaic KS. In future, we are planning to place him on androgen replacement as well. Learning points: •• Ambiguous genitalia with subsequent development of sexual precocity in a phenotypic male points towards some unusual varieties of CAH. •• High level of serum testosterone, adrenal androgen, plasma ACTH and low basal cortisol are proof of CAH, whereas elevated level of 17-OH pregnenolone is biochemical marker of 3β-HSD enzyme deficiency. •• Final diagnosis can be obtained with sequencing of HSD3B2 gene showing various mutations. •• Presence of bilateral cryptorchidism in such a patient may be due to underlying hypogonadism. •• Karyotyping in such patient may rarely show mosaic KS (47,XXY/46,XX) and there might be unmasking of hypergonadotropic hypogonadism resulting from adrenal androgen suppression from glucocorticoid treatment.

Arsenic level in toenails is associated with hearing loss in humans

Arsenic (As) pollution in drinking water is a worldwide health risk for humans. We previously showed hearing loss in young people who live in areas of As-polluted drinking water and in young mice orally treated with As. In this study, we epidemiologically examined associations between As levels in toenails and hearing in 145 Bangladeshi aged 12-55 years in 2014. Levels of As in toenails, but not those in urine, were shown to be significantly correlated with hearing loss at 4 kHz [odds ratio (OR) = 4.27; 95% confidence interval (CI): 1.51, 12.05], 8 kHz (OR = 3.91; 95% CI: 1.47, 10.38) and 12 kHz (OR = 4.15; 95% CI: 1.55, 11.09) by multivariate analysis with adjustments for age, sex, smoking and BMI. Our experimental study further showed a significant association between As levels in inner ears and nails (r = 0.8113, p = 0.0014) in mice orally exposed to As, suggesting that As level in nails is a suitable index to assess As level in inner ears. Taken together, the results of our study suggest that As level in nails could be a convenient and non-invasive biomarker for As-mediated hearing loss in humans.

Impairment of extra-high frequency auditory thresholds in subjects with elevated levels of fasting blood glucose

This study was performed to assess whether there is an association between elevated Fasting Blood Glucose (FBG) and hearing impairment in Bangladeshi population. A total of 142 subjects (72 with elevated FBG; 70 control) were included in the study. The mean auditory thresholds of the control subjects at 1, 4, 8 and 12 kHz frequencies were 6.35 ± 0.35, 10.07 ± 0.91, 27.57 ± 1.82, 51.28 ± 3.01 dB SPL (decibel sound pressure level), respectively and that of the subjects with elevated FBG were 8.33 ± 0.66, 14.37 ± 1.14, 38.96 ± 2.23, and 71.11 ± 2.96 dB, respectively. The auditory thresholds of the subjects with elevated FBG were significantly (p < 0.05) higher than the control subjects at all the above frequencies, although hearing impairment was most evidently observed at an extra-high (12 kHz) frequency. Subjects with a long duration of diabetes (>10 years) showed significantly (p < 0.05) higher level of auditory thresholds at 8 and 12 kHz, but not at 1 and 4 kHz frequencies, compared to subjects with shorter duration of diabetes (≤10 years). In addition, based on the data of odds ratio, more acute impairment of hearing at the extra-high frequency was observed in diabetic subjects of both older (>40 years) and younger (≤40 years) age groups compared to the respective controls. The binary logistic regression analysis showed a 5.79-fold increase in the odds of extra-high frequency hearing impairment in diabetic subjects after adjustment for age, gender and BMI. This study provides conclusive evidence that auditory threshold at an extra-high frequency could be a sensitive marker for hearing impairment in diabetic subjects.

A comprehensive study including monitoring, assessment of health effects and development of a remediation method for chromium pollution

Chromium (Cr) pollution caused by wastewater from tanneries is a worldwide environmental problem. To develop a countermeasure, we performed a comprehensive study using Hazaribagh, the tannery area in Dhaka City, Bangladesh, as a model. Our environmental monitoring indicated that the soluble form of Cr, but not barium or arsenic, in Buriganga River is derived from Hazaribagh. Our chemical analysis next showed that Cr, the primary pollutant in canal water at Hazaribagh, consisted of ≤0.7 μM hexavalent Cr [Cr(VI)] and ≤1705 μM trivalent Cr [Cr(III)]. Our biological study then showed that coexposure to Cr(VI) and Cr(III) at possible ratios in canal water at Hazaribagh synergistically promotes transforming activity of human non-tumorigenic HaCaT keratinocytes with activated MEK/ERK and AKT. Our environmental engineering study finally indicated that a magnesium and iron-based hydrotalcite-like compound (MF-HT), our original depurative, can maximally adsorb 9.0 mg/g Cr(VI) and 1041 mg/g Cr(III). Our results suggested the importance of removal of Cr(III) as well as Cr(VI) by showing that Cr(III), which is generally recognized as a chemical with low toxicity, synergistically promoted carcinogenicity of a low level of Cr(VI). Therefore, we propose the use of our original high-efficient and low-cost depurative as a countermeasure to address the worldwide problem of environmental Cr pollution.

Material challenges for solar cells in the twenty-first century: directions in emerging technologies

Photovoltaic generation has stepped up within the last decade from outsider status to one of the important contributors of the ongoing energy transition, with about 1.7% of world electricity provided by solar cells. Progress in materials and production processes has played an important part in this development. Yet, there are many challenges before photovoltaics could provide clean, abundant, and cheap energy. Here, we review this research direction, with a focus on the results obtained within a Japan-French cooperation program, NextPV, working on promising solar cell technologies. The cooperation was focused on efficient photovoltaic devices, such as multijunction, ultrathin, intermediate band, and hot-carrier solar cells, and on printable solar cell materials such as colloidal quantum dots.

Manganese in toenails is associated with hearing loss at high frequencies in humans

PURPOSE

Elevated hearing thresholds from high frequencies are known to be one of the hallmarks of age-related hearing loss. Our recent study showed accumulation of manganese (Mn) in inner ears resulting in acceleration of age-related hearing loss in mice orally exposed to Mn. However, there is no evidence showing an association between Mn in non-invasive biological samples and hearing loss in humans evaluated by pure tone audiometry (PTA). In this study, we evaluated Mn in non-invasive biological samples as a possible biomarker for hearing loss in humans.

MATERIALS AND METHODS

We determined hearing levels by PTA and Mn levels in toenails, hair and urine with an inductively coupled plasma mass spectrometer (ICP-MS) in 145 healthy subjects in Bangladesh.

RESULTS

Multivariable analyses showed that Mn levels in toenails, but not in hair and urine samples, were significantly associated with hearing loss at 8 kHz and 12 kHz. Moreover, our experimental study showed a significant correlation between Mn levels in inner ears and nails, but not hair, in mice orally exposed to Mn.

CONCLUSIONS

The results provide novel evidence that Mn in toenails is a possible biomarker for hearing loss at high frequencies in humans.

Arsenic levels in cutaneous appendicular organs are correlated with digitally evaluated hyperpigmented skin of the forehead but not the sole in Bangladesh residents

There has been no report showing the effect of arsenic level on digitized skin pigmentation level, a typical diagnostic marker for arsenicosis. Correlations among history of drinking well water, arsenic levels in hair and toenails, and digitalized skin pigmentation levels (L*-value) in sunlight-exposed (forehead) and unexposed (sole) skin areas digitally evaluated by using a reflectance spectrophotometer were examined in 150 residents of Bangladesh. Univariate analysis showed that arsenic levels in hair and toenails of subjects with a history of drinking well water were 10.6-fold and 7.1-fold higher, respectively, than those in subjects without a history of drinking well water. The mean L*-value of foreheads, but not that of soles, in subjects with a history of drinking well water was 1.15-fold lower (more pigmented) than that in subjects without a history of drinking well water. Significant correlations were found between duration of drinking well water and arsenic concentrations in hair (r=0.63; P<0.01) and toenails (r=0.60; P<0.01). Multivariate analysis showed that the arsenic levels in hair and toenails and the duration of drinking well water were strongly correlated with the digitized pigmented level of the forehead but not that of the sole. An increase in the duration of drinking well water may increase hyperpigmentation in the forehead, but not that in the sole, through an increased arsenic level in the human body as shown in cutaneous appendicular organs (hair and toenails).

Oral exposure to arsenic causes hearing loss in young people aged 12-29 years and in young mice

There is no information on the association between oral exposure to arsenic (As) and hearing loss in humans or mice. In this combined epidemiological study and experimental study, the association of oral exposure to As with hearing loss in people aged 12–29 years and young mice was examined. Subjects in the exposure group (n = 48), who were drinking tube well water contaminated with As, showed significantly higher risks of hearing loss at 4 kHz [odds ratio (OR) = 7.60; 95% confidence interval (CI): 1.56, 57.88], 8 kHz (OR = 5.00; 95% CI: 1.48, 18.90) and 12 kHz (OR = 8.72; 95% CI: 2.09, 47.77) than did subjects in the control group (n = 29). We next performed an experiment in which young mice were exposed to As via drinking water at 22.5 mg/L, which is a much greater concentration than that in human studies. The exposure group showed hearing loss and accumulation of As in inner ears. Ex vivo exposure of the organ of Corti from mice exposed to As significantly decreased the number of auditory neurons and fibers. Thus, our combined study showed that oral exposure to As caused hearing loss in young people and young mice.

Epidemiological analysis of the association between hearing and barium in humans

Our previous study experimentally showed barium (Ba)-mediated hearing loss in mice. To our knowledge, however, it remains unknown whether Ba affects hearing in humans. This epidemiological study aimed at investigating ototoxicity of Ba in humans. Associations of Ba levels in hair, toenails and urine with hearing levels (1, 4, 8 and 12 kHz) were analyzed in 145 Bangladeshi subjects. Binary logistic regression analysis with adjustment for age, sex, body mass index (BMI) and smoking showed that Ba levels in hair had significant associations with hearing loss at 8 kHz (OR=4.75; 95% CI: 1.44, 17.68) and 12 kHz (OR=15.48; 95% CI: 4.04, 79.45). Ba levels in toenails were also associated with hearing loss at 8 kHz (OR=3.20; 95% CI: 1.35, 7.85) and 12 kHz (OR=3.63; 95% CI: 1.58, 8.55), whereas there was no correlation between Ba level in urinary samples and hearing. There was a significant correlation between hearing loss and Ba levels in hair and toenails in the model adjusted with arsenic levels as the confounder. In conclusion, this study suggested that Ba levels could be a new risk factor for hearing loss, especially at high frequencies of 8 and 12 kHz, in humans.

Tea Extract Prevents Arsenic-mediated DNA Damage and Death of Murine Thymocytes in vitro

Groundwater contamination by arsenic has created a major health hazard in Bangladesh by affecting millions of people. In this study, we report cytotoxic effects of arsenic in primary culture of murine thymocytes and the counteractive actions of tea extract to reduce this cytotoxic effects. When murine thymocytes were incubated for shorter period (1 h) with higher concentrations (50 and 100 ?M) of sodium arsenite (NaAsO2), cell viability was decreased to 79.06 ± 0.52% and 62.53 ± 0.23%, respectively. In case of longer incubation (16 hrs) with a wide range of NaAsO2 concentration (1-100 ?M), cell viability was reduced from 89.30 ± 0.84% to 79.0 ± 0.52% by 1 ?M NaAsO2, and this reduction was continued with increasing concentration reaching to 29.60 ± 0.72% by 100 ?M. Tea is known to possess antioxidant property and we found that this tea extract reduced NaAsO2-mediated death of the cells in culture. After 16 h of incubation, the chromosomal DNA of 5 ?M NaAsO2-exposed cells was found degraded suggesting apoptotic death of the cells. Interestingly, this degradation of chromosomal DNA was blocked by tea extract. All of these results together suggest a future therapeutic application of tea extract to reduce or block arsenic toxicity.Dhaka Univ. J. Pharm. Sci. 14(1): 79-85, 2015 (June)

Antibacterial activities of the Methanolic extract of Bangladeshi Black tea against various human pathogens

The goal of the present study was to evaluate the antibacterial activity of the methanolic extract of Bangladeshi black tea against various important pathogenic bacteria. Antibacterial activity test was carried out by agar well-diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated using microdilution methods. Extract of Bangladeshi black tea demonstrated potential antibacterial activity in a dose dependent manner against all of the tested bacteria and exhibited highest activity against two common enteric pathogens, Shigella boydii and Vibrio cholerae with MIC and MBC of 200 ?g/ml and 1 mg/ml respectively. Our results indicate that black tea extract can be used as therapeutic to control these deadly pathogens. DOI: http://dx.doi.org/10.3329/dujps.v13i1.21873 Dhaka Univ. J. Pharm. Sci. 13(1): 97-103, 2014 (June)

Arsenic adsorption by Bacterial Extracellular Polymeric Substances

The main objective of this work was to isolate arsenic resistant bacteria from contaminated soil, followed by screening for their ability to adsorb arsenic. Six bacterial isolates (S1 to S6) were obtained from arsenic contaminated soil samples and among these, five (S1, S2, S3, S5 and S6) were characterized as bacillus and the rest one (S4) was cocci depending on shape. All the isolates except S6 produced extracellular polymeric substances (EPS) in the culture medium and displayed arsenic adsorbing activities demonstrated by adsorption of around 90% from initial concentration of 1 mg/L sodium arsenite. To clarify the role of EPS, we killed the bacteria that produced EPS and used these killed bacteria to see whether they could still adsorb arsenic or not. We found that they could adsorb arsenic similarly like that of EPS produced live bacterial isolates. From the observation it is concluded that these isolates showed potentiality to adsorb arsenic and hence might be used for bioremediation of arsenic. DOI: http://dx.doi.org/10.3329/bjm.v28i2.11821 Bangladesh J Microbiol, Volume 28, Number 2, December 2011, pp 80-83

Reduction of Sodium Arsenite-Mediated Adverse Effects in Mice using Dietary Supplementation of Water Hyacinth (Eichornia crassipes) Root Powder

BACKGROUND

In this study, we evaluated the protective effects of water Hyacinth Root Powder (HRP) on arsenic-mediated toxic effects in mice.

METHODS

Swiss albino mice, used in this study, were divided into four different groups (for each group n=5). The control group was supplied with normal feed and water, Arsenic group (As-group) was supplied with normal feed plus arsenic (sodium arsenite)-containing water, and arsenic+hyacinth group (As+Hy group) was supplied with feed supplemented with HRP plus arsenic water. The remaining Hy-group was supplied with feed supplemented with HRP plus normal water.

RESULTS

Oral administration of arsenic reduced the normal growth of the mice as evidenced by weight loss. Interestingly, tip of the tails of these mice developed wound that caused gradual reduction of the tail length. Supplementation of HRP in feed significantly prevented mice growth retardation and tail wounding in As+Hy group mice. However, the growth pattern in Hy-group mice was observed to be almost similar to that of the control group indicating that HRP itself has no toxic or negative effect in mice. Ingested arsenic also distorted the shape of the blood cells and elevated the serum enzymes such as lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and serum glutamic pyruvic transaminase (SGPT). Importantly, elevation of these enzymes and distortion of blood cell shape were partially reduced in mice belong to As+Hy group, indicating HRP-mediated reduction of arsenic toxicity.

CONCLUSION

Therefore, the preventive effect of hyacinth root on arsenic-poisoned mice suggested the future application of hyacinth to reduce arsenic toxicity in animal and human.

Kidney allocation to liver transplant candidates with renal failure of undetermined etiology: role of percutaneous renal biopsy

The feasibility, value and risk of percutaneous renal biopsy (PRB) in liver transplant candidates with renal failure are unknown. PRB was performed on 44 liver transplant candidates with renal failure of undetermined etiology and glomerular filtration rate (GFR) <40 mL/min/1.73 m(2) (n = 37) or on renal replacement therapy (RRT) (n = 7). Patients with >or=30% interstitial fibrosis (IF), >or=40% global glomerulosclerosis (gGS) and/or diffuse glomerulonephritis were approved for simultaneous-liver-kidney (SLK) transplantation. Prebiopsy GFR, urinary sodium indices, dependency on RRT and kidney size were comparable between 27 liver-transplant-alone (LTA) and 17 SLK candidates and did not relate to the biopsy diagnosis. The interobserver agreement for the degree of IF or gGS was moderate-to-excellent. After a mean of 78 +/- 67 days, 16 and 8 patients received LTA and SLK transplants. All five LTA recipients on RRT recovered kidney function after transplantation and serum creatinine was comparable between LTA and SLK recipients at last follow-up. Biopsy complications developed in 13, of these, five required intervention. PRB is feasible in liver transplant candidates with renal failure and provides reproducible histological information that does not relate to the pretransplant clinical data. Randomized studies are needed to determine if PRB can direct kidney allocation in this challenging group of liver transplant candidates.

Continued influence of preoperative renal function on outcome of orthotopic liver transplant (OLTX) in the US: where will MELD lead us?

Renal function is a component of the Model for End Stage Liver Disease (MELD), We queried the 1999-2004 OPTN/UNOS database to determine whether preoperative renal function remained an important determinant of survival in primary deceased donor liver transplant alone patients (DDLTA) or primary combined kidney liver transplant patients (KLTX). We examined preoperative creatinine, renal replacement therapy (RRT), incidence of KLTX, and patient survival in the 34 months before and after introduction of MELD and performed a multivariate Cox regression analysis of time to death. Preoperative renal function is an independent predictor of survival in DDLTA but not in KLTX. When compared to DDLTA with a preoperative serum creatinine of 0-0.99 mg/dL, patients with serum creatinine from 1-1.99 mg/dL, >2.0 mg/dL, those requiring RRT, and those receiving KLTX had a relative risk of death following transplant of 1.11, 1.58, 1.77, and 1.44 respectively. KLTX requiring RRT had better survival than DDLTA requiring RRT. Since introduction of MELD, KLTX, preoperative creatinine, and number of patients requiring preoperative RRT have increased. Despite this, patient survival following orthotopic liver transplant (OLTX) in the 34 months after introduction of MELD is not different than prior to introduction of MELD.

Overexpression in Escherichia coli and functional reconstitution of anchovy trypsinogen from the bacterial inclusion body

We have synthesized and optimized a high-yielding Escherichia coli expression system to produce trypsinogen from anchovy Engraulis japonicus and have developed conditions for its successful refolding. Recombinant anchovy trypsinogen precipitated in E. coli Rosetta (DE3) pLacI strain as inclusion bodies was denatured by 6 M guanidine-HCl followed by refolding with drop wise addition to a large excess of a folding buffer containing 0.5 M non-detergent sulfobetaine (NDSB-251) and a redox potential of oxidized and reduced glutathiones. The folded trypsinogen was autocatalytically activated to its mature form, trypsin, and purified with a MonoQ ion-exchange column. NH2-terminal amino acid sequencings revealed that E. coli efficiently processed NH2-terminal methionine residue from the expressed trypsinogen and that trypsinogen was activated at the correct site to generate active trypsin. The recombinant enzyme showed kinetic properties comparable to those of the native enzyme and demonstrated a typical cleavage preference for arginine over lysine residue against a protein substrate. The optimized expression and folding procedures yielded 12 mg of purified, active trypsin from 1 L of bacterial culture or 45 g wet weight cells, which is quite enough for various analytical and semipreparative purposes.

Epstein-Barr virus transforming protein LMP1 plays a critical role in virus production

The Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1), which is critical for EBV-induced B-cell transformation, is also abundantly expressed during the lytic cycle of viral replication. However, the biological significance of this strong LMP1 induction remains unknown. We engineered a bacterial artificial chromosome clone containing the entire genome of Akata strain EBV to specifically disrupt the LMP1 gene. Akata cell clones harboring the episomes of LMP1-deleted EBV were established, and the effect of LMP1 loss on virus production was investigated. We found that the degree of viral DNA amplification and the expression levels of viral late gene products were unaffected by LMP1 loss, demonstrating that the LMP1-deleted EBV entered the lytic replication cycle as efficiently as the wild-type counterpart. This was confirmed by our electron microscopic observation that nucleocapsid formation inside nuclei occurred even in the absence of LMP1. By contrast, loss of LMP1 severely impaired virus release into culture supernatants, resulting in poor infection efficiency. The expression of truncated LMP1 in Akata cells harboring LMP1-deleted EBV rescued the virus release into the culture supernatant and the infectivity, and full-length LMP1 partially rescued the infectivity. These results indicate that inducible expression of LMP1 during the viral lytic cycle plays a critical role in virus production.

Production of high-titer Epstein-Barr virus recombinants derived from Akata cells by using a bacterial artificial chromosome system

An Epstein-Barr virus (EBV) genome in Burkitt's lymphoma-derived cell line Akata was cloned into a bacterial artificial chromosome (BAC) vector. The BAC clone, designated AK-BAC, was rapidly and precisely modified by means of efficient homologous recombination in Escherichia coli. This system was used to produce recombinant EBVs with transgenes. An expression cassette of green fluorescent protein (GFP) was inserted into AK-BAC, and the resultant BAC clone, AK-BAC-GFP, was transfected into Akata cells. We found that transfected BAC plasmids efficiently formed episomes in EBV-positive Akata cells. Mixtures of wild-type and AK-BAC-GFP viruses were then produced and used to infect EBV-negative Akata cells. We obtained cell clones that harbored only AK-BAC-GFP but no wild-type episome. These cell clones produced infectious viruses after stimulating virus production, and the recombinant viruses of AK-BAC-GFP efficiently immortalized primary B lymphocytes. We further revised the method so that any kind of cDNA could be rapidly inserted into the unique I-PpoI site that had been artificially introduced into AK-BAC. The AK-BAC system will have a broad range of applications, such as genetic analyses of various viral gene products and development of viral vectors for human gene therapy.

Genetic basis of heterosis and inbreeding depression in rice (Oryza sativa L.)

The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.). The characters were plant height, days to flag leaf initiation, days to first panicle initiation, days to 100% flowering, panicle length, flag leaf length, days to maturity, number of fertile spikelet/panicle, number of effective tillers/hill, grain yield/10-hill, and 1000-grain weight. In general the hybrids performed significantly better than the respective parents. Significant heterosis was observed for most of the studied characters. Among the 10 hybrids, four hybrids viz., 17Ax45R, 25Ax37R, 27Ax39R, 31Ax47R, and 35Ax47R showed highest heterosis in 10-hill grain yield/10-hill. Inbreeding depression of F2 progeny was also studied for 11 characters of 10 hybrids. Both positive and negative inbreeding depression were found in many crosses for the studied characters, but none was found significant. Selection of good parents was found to be the most important for developing high yielding hybrid rice varieties.

Induction immunotherapy with IL-2Ra monoclonal antibody in kidney transplantation

The development of new immunosuppressive agents is designed to reduce the incidence and severity of early acute post-transplant rejection. One potential target for more specific immunosuppressive therapy with monoclonal antibodies is the high affinity a chain of interleukin-2 receptors (IL-2Ra). Clinical investigation of murine IL-2Ra monoclonal antibodies (IL-2Ra mAb) in renal transplantation has indicated that a complete blockade of IL-2Ra during the critical first post-transplant months allows effective immunoprophylaxis, especially in the early post-transplant period. Efficacy of these agents, however, is hampered by their short disposition half-lives in humans and their immunogenicity in the form of neutralizing human antimouse antibodies. These inherent problems can be partially overcome by chi-meric, hyper-chimeric (humanized) products and multiple dose regimens. Both IL-2Ra mAbs: daclizumab (humanized) and basiliximab (chimeric) currently approved for clinical use have been found to reduce the frequency of acute rejections in renal transplant recipients without an apparent increase in short-term toxicities. In most transplant centers where these agents are utilized, they are being routinely administered as induction immunoprophylaxis in recommended multiple dose regimens to recipients of solid organ transplants. Others have restricted their use to certain high-risk patients such as those undergoing multi-organ transplantation, recipients with high panel-reactive antibodies, African-Americans, patients at risk for developing delayed graft function (DGF), and children. Recently some investigators have successfully administered these antibodies co-administered with newer immunosuppressive agents in limited dose protocols thus developing cost effective and simplified regimens. Therefore, in the absence of a favorable long-term efficacy, it is likely that these agents will be administered in limited dose protocols along with one of the modulators of IL-2, i.e. calcineurin inhibitors (CNI), to a selected group of patients in whom additional immunosuppression in the early post-transplantation period is desirable.

Lipid formulations of polyene antifungal drugs and attenuation of associated nephrotoxicity

Amphotericin B is an effective broad-spectrum antifungal agent, but various side effects, especially nephrotoxicity, have restricted its use. Recently, lipid formulations of amphotericin B have been developed in order to reduce its toxic side effects. Clinical trials, although in the early stages, suggest promising results, and that some of these lipid formulations are potent and less toxic, even at higher doses. We summarize herein the existing information about newer lipid formulations of polyene antifungal drugs, which could attenuate associated nephrotoxicity.

Myoglobinuria: evaluation of methods in the clinical diagnosis acute renal failure

Patients with red--brown urine which may be a sign of myoglobinuria, can develop acute renal failure. We assayed serum creatinine, blood urea nitrogen (BUN) and creatine kinase activity in a total of 33 patients of equal groups, A (automobile accident), B (trauma) and C (undergoing rhabdomyolysis). In addition we tested 132 urine samples for the presence of myoglobin using a dipstick assay. Only five patients in group A showed any sign of myoglobinuria with increased creatine kinase activity upto 7 times the normal value but their serum creatinine level and BUN were within the normal range. In contrast, all 22 patients in group B and C showed myoglobinuria and above normal concentrations of serum creatinine and BUN, with significantly increased (p < 0.0001) creatine kinase activity upto 150 times the normal range. Four of the most seriously ill patients in group C developed acute renal failure. Supplementation of routine determinations of serum creatinine and BUN and serum creatine kinase activity with a rapid test for myoglobinuria provides an extra indication of impending renal dysfunction. It may be beneficial in the emergency management of these patients.

Randomized trial of tacrolimus plus mycophenolate mofetil or azathioprine versus cyclosporine oral solution (modified) plus mycophenolate mofetil after cadaveric kidney transplantation: results at 2 years

BACKGROUND

A previous report described the 1-year results of a prospective, randomized trial designed to investigate the optimal combination of immunosuppressants in kidney transplantation. Recipients of first cadaveric kidney allografts were treated with tacrolimus+mycophenolate mofetil (MMF), cyclosporine oral solution (modified) (CsA)+MMF, or tacrolimus+azathioprine (AZA). Results at 1 year revealed that optimal efficacy and safety were achieved with a regimen containing tacrolimus+MMF. The present report describes results at 2 years.

METHODS

Two hundred twenty-three recipients of first cadaveric kidney allografts were randomized to receive tacrolimus+MMF, CsA+MMF, or tacrolimus+AZA. All regimens contained corticosteroids, and antibody induction was used only in patients who experienced delayed graft function. Patients were followed up for 2 years.

RESULTS

The results at 2 years corroborate and extend the findings of the previous report. Patients randomized to either treatment arm containing tacrolimus experienced improved kidney function. New-onset insulin dependence remained in four, three, and four patients in the tacrolimus+MMF, CsA+MMF, and tacrolimus+AZA treatment arms, respectively. Furthermore, patients with delayed graft function/acute tubular necrosis who were treated with tacrolimus+MMF experienced a 23% increase in allograft survival compared with patients receiving CsA+MMF (P=0.06). Patients randomized to tacrolimus+MMF received significantly lower doses of MMF compared with those administered CsA+MMF.

CONCLUSIONS

All three immunosuppressive regi-mens provided excellent safety and efficacy. How-ever, the best results overall were achieved with tacrolimus+MMF. The combination may provide particular benefit to kidney allograft recipients who develop delayed graft function/acute tubular necrosis. Renal function at 2 years was better in the tacrolimus treatment groups compared with the CsA group.

Infusion of total dose iron versus oral iron supplementation in ambulatory peritoneal dialysis patients: a prospective, cross-over trial

The efficacy of intermittent, small doses of intravenous iron in hemodialysis patients is well established. But poor peripheral vascular access and frequency of therapy preclude acceptability of this method in peritoneal dialysis (PD) patients. Therefore, despite its marginal efficacy, oral iron remains the common method of iron supplementation in these patients. This prospective, cross-over trial compares infusion of total dose iron (ITDI) and oral iron supplementation in outpatient PD patients. Eleven stable CAPD patients with an hematocrit (Hct) of less than 33%, or a transferrin saturation (TSAT) of less than 30%, or both, were entered into the study. The study design included an oral phase [4 months, ferrous sulfate 325 mg (195 mg elemental iron), three times daily], a "wash-out" phase (1 month, no iron supplementation), and an ITDI phase [4 months, single infusion over 4 hours of 1 g iron dextran mixed in 1/2 normal saline]. Laboratory parameters were monitored monthly, and subcutaneous recombinant human erythropoietin (rHuEPO) doses were adjusted monthly to maintain a hematocrit above 33%. Patients with hyperparathyroidism, aluminum toxicity, and weekly Kt/V below 1.8 were excluded. Nine patients [8 Caucasians, 1 African American; causes of end-stage renal disease (ESRD): hypertension (4 cases), diabetes (3 cases), glomerulonephritis (1 case), and polycystic kidney disease (1 case); mean age: 43.3 +/- 2 years; mean weight: 73.0 +/- 4 kg; duration of ESRD: 28 +/- 13 months] completed the 9-month study. During the oral phase, TSAT rapidly decreased and a higher dose of rHuEPO failed to maintain Hct, a pattern sustained during the "wash-out" phase. During the ITDI phase, TSAT significantly increased and improvement in Hct resulted in a significant lowering of rHuEPO doses. The ITDI therapy was well tolerated. We conclude that ITDI is the preferred method of iron supplementation in outpatient PD patients.

Heat shock protein 47 in renal scarring

Heat shock protein 47 (HSP47) is a collagen-binding protein, thought to play an essential mechanistic role in the assembly and processing of procollagens. HSP47 is increasingly being implicated in the pathogenesis of several human and experimental fibrotic diseases. HSP47 could mediate increased accumulation of collagens in the fibrotic mass, possibly by regulating increased assembly of procollagens. Therefore, modulation of HSP47 might be a valuable tool for manipulation of some fibrotic diseases, including renal scarring

Expression of angiotensin II type I receptor on erythroid progenitors of patients with post transplant erythrocytosis

BACKGROUND

The pathogenesis of posttransplant erythrocytosis (PTE) has been elusive. Angiotensin converting enzyme inhibitors (ACEI) are efficacious in lowering the hematocrit of patients with PTE and angiotensin II (AII) type I receptors (AT1R) were recently detected on red blood cell precursors, burst-forming unit-erythroid- (BFU-E) derived cells. The purpose of this study was to determine whether there is increased expression of the AT1R on BFU-E-derived cells of patients with PTE, which might contribute to the pathogenesis of PTE.

METHODS

Twelve healthy volunteers and 25 transplant recipients (13 patients with and 12 without PTE) were studied. BFU-E from peripheral blood were cultured in methylcellulose and BFU-E-derived colonies were harvested on day 10. Western blotting was used to detect AT1R and erythropoietin receptor (EpoR) expression. Intracellular free calcium in response to AII and erythropoietin (Epo) was measured with digital video imaging.

RESULTS

There were no differences between transplant patients, with and without PTE, with respect to weight, age, sex, blood pressure, serum creatinine, circulating renin, angiotensin II, and Epo levels. Hematocrit, red blood cell number, BFU-E-derived colony number,and size were significantly increased in PTE compared with other two groups. AT1R expression was increased by 44% on the erythroid progenitors of PTE versus non posttransplant erythrocytosis patients and by 32% in PTE patients versus normal volunteers. AT1R expression correlated significantly with the hematocrit in PTE (Spearman r=0.68, P=0.01). In contrast, EpoR expression was equivalent in all groups. The AT1R was functional since a significant increase in [Ca(i)] was observed in Fura-2 loaded day 10 cells when stimulated with AII (182%, P<0.0001).

CONCLUSION

An increase in AT1R density was observed in erythroid precursors of transplant patients with PTE compared to those without PTE and normal volunteers, and the level of AT1R expression in PTE correlated significantly with the hematocrit. In contrast, EpoR expression was not different in PTE compared with non posttransplant erythrocytosis or normal controls. This study supports a role for the AT1 receptor signaling pathway in the pathogenesis of PTE.

Laparoscopic-assisted renal biopsy: an alternative to open approach

An open renal biopsy frequently is performed when the conventional percutaneous approach is contraindicated. Although many of the surgical procedures, previously performed by a traditional open technique, are now successfully accomplished by laparoscopic technique, there remains a paucity of reports on laparoscopic kidney biopsy. We describe the use of laparoscopic technique in performing native kidney biopsy in three patients and review the potential safety and accuracy of this approach. To date, laparoscopic-assisted renal biopsy has been reported in six patients. The average length of stay in our small series was 1.3 days, and there were no major or catastrophic complications. Adequate numbers of glomeruli for confirmation of microscopic diagnosis were obtained in all cases. The review of literature, in addition to our encouraging preliminary results of a small group of patients, shows a possible role of laparoscopic-assisted renal biopsy in place of an open renal biopsy.

In vivo and in vitro modulation of immune stimulatory capacity of primary dendritic cells by adenovirus-mediated gene transduction

Dendritic cells (DCs) are potent antigen-presenting cells which are key leukocytes in the initiation of cell-mediated organ graft rejection, antiviral immunity, and antitumor responses. In this study we demonstrate that genetic modification of primary human and mouse DCs by adenoviral gene transfer is an effective means of induction and modulation of antigen presentation by DCs. An adenovirus vector (AdLacZ) was used to express an intracellular model antigen beta-galactosidase (beta-gal) in DCs. Our results show that 30-40% of precursor dendritic cells (PDCs) derived from human umbilical cord blood and circulating mature blood DCs express high levels beta-galactosidase (beta-gal) after infection with AdLacZ with no cytopathic effect observed. In vitro, AdLacZ transduced PDCs and DCs demonstrated a 10- to 20-fold higher mixed lymphocyte reaction (MLR) stimulatory capacity as compared to that of monocytes. In vivo, immunization with AdLacZ transduced mouse DCs resulted in more potent cytotoxic T lymphocyte (CTL) responses against the predicted H-2 restricted beta-gal epitope as compared to CTL responses obtained by beta-gal peptide pulsed DCs. Modulations of the MLR stimulatory capacity of DCs were examined by expression of mouse B7 and CTLA-4Ig. The results show that expression of mouse B7 by a recombinant adenoviral vector (Ad7) significantly enhances the MLR stimulatory capacity of human DCs. In contrast, expression of CTLA-4Ig (AdCTLA-4Ig) reduces the MLR stimulatory capacity of the transduced cells. We conclude that recombinant adenovirus can readily be used for genetic modulation DC-induced immune responses in vivo and in vitro. DCs targeted for induction of specific antigen responses or for modulation of the immune stimulatory capacity may have a potential use in the control of transplantation rejection or viral infections.

Randomized trial of tacrolimus (Prograf) in combination with azathioprine or mycophenolate mofetil versus cyclosporine (Neoral) with mycophenolate mofetil after cadaveric kidney transplantation

BACKGROUND

Our clinical trial was designed to investigate the optimal combination of immunosuppressants for renal transplantation.

METHODS

A randomized three-arm, parallel group, open label, prospective study was performed at 15 North American centers to compare three immunosuppressive regimens: tacrolimus + azathioprine (AZA) versus cyclosporine (Neoral) + mycophenolate mofetil (MMF) versus tacrolimus + MMF. All patients were first cadaveric kidney transplants receiving the same maintenance corticosteroid regimen. Only patients with delayed graft function (32%) received antilymphocyte induction. A total of 223 patients were randomized, transplanted, and followed for 1 year.

RESULTS

There were no significant differences in baseline demography between the three treatment groups. At 1 year the results are as follows: acute rejection 17% (95% confidence interval 9%, 26%) in tacrolimus + AZA; 20% (confidence interval 11%, 29%) in cyclosporine + MMF; and 15% (confidence interval 7%, 24%) in tacrolimus + MMF. The incidence of steroid resistant rejection requiring antilymphocyte therapy was 12% in the tacrolimus + AZA group, 11% in the cyclosporine + MMF group, and 4% in the tacrolimus + MMF group. There were no significant differences in overall patient or graft survival. Tacrolimus-treated patients had a lower incidence of hyperlipidemia through 6 months posttransplant. The incidence of posttransplant diabetes mellitus requiring insulin was 14% in the tacrolimus + AZA group, 7% in the cyclosporine + MMF and 7% in the tacrolimus + MMF groups.

CONCLUSIONS

All regimens yielded similar acute rejection rates and graft survival, but the tacrolimus + MMF regimen was associated with the lowest rate of steroid resistant rejection requiring antilymphocyte therapy.

ITDI is the preferred treatment for iron supplementation in rHuEpo-treated anemic PD patients

In recombinant human erythropoietin (rHuEpo)-treated anemic peritoneal dialysis (PD) patients, oral iron therapy, despite its limited efficacy, remains an accepted and convenient method of iron supplementation. In this study, we compared infusion of total dose iron (ITDI) to oral iron for the treatment of anemia in PD patients. Thirteen patients with serum transferrin saturation (TSAT) < 25% received ITDI and 11 patients with TSAT between 25% to 35% received oral iron. Doses of rHuEpo were adjusted monthly to maintain target hematocrit at 35%. Both groups had similar baseline mean hematocrits (31.0 +/- 0.9% vs. 33.0 +/- 1.0%), and comparable mean baseline weekly rHuEpo dose (7886 +/- 1449 units/week vs. 6370 +/- 1553 units/week). At the end of the 6-month study, the ITDI group had a 16% improvement in mean hematocrit compared to baseline. The final mean dose of weekly rHuEpo was also reduced by 59% in the ITDI group. During the same period, compared to baseline, the oral group had a 4.8% fall in mean hematocrit despite 51% higher requirement of rHuEpo doses. There was no adverse reaction to intravenous iron. We conclude that ITDI is the preferred treatment for iron supplementation in rHuEpo-treated anemic PD patients.

Prednisone withdrawal in kidney transplant recipients on cyclosporine and mycophenolate mofetil--a prospective randomized study. Steroid Withdrawal Study Group

BACKGROUND

Prospective randomized trials have shown a reduced rate of acute rejection (AR) in mycophenolate mofetil-treated kidney transplant recipients. We hypothesized that this increased protection from AR could allow successful prednisone (P) withdrawal in cyclosporine/mycophenolate mofetil/P-treated recipients.

METHODS

A multicenter, prospective, randomized, double-blind trial of P withdrawal at 3 months post-transplant was initiated. Entry criteria were: primary transplant, adult, no AR by 90 days, mycophenolate mofetil dose > or =2 g/day, cyclosporine dose = 5-15 mg/kg/ day, P dose = 10-15 mg/day. Study participants were randomized to have P tapered over 8 weeks (beginning at 3 months posttransplant) to 0 vs. 10 mg/day. Prestudy power analysis determined 500 recipients should be randomized for 80% statistical power to test equivalence of the primary endpoint, AR, or treatment failure at 1 year posttransplant. By design, the study was to be stopped if interim data precluded reaching equivalence. An established data safety monitoring board monitored the study.

RESULTS

After 266 patients were enrolled, the patient enrollment was stopped (after safety monitoring board review) because of excess rejection in the P withdrawal group. The Kaplan-Meier estimate of the cumulative incidence of rejection or treatment failure within 1 year posttransplant (+/-95% confidence interval) for the maintenance group was 9.8% (4.4%; treatment failure, 14.9%); for the withdrawal group, 30.8% (21.0%; 39.3%). Treatment differences in the distribution of time to event were highly significant (P = 0.0007). Of note, risk was higher in blacks (39.6%) versus nonblacks (16.0%) (P<0.001). At 1 year post-transplant, there was no difference between groups in patient or graft survival. For the patients with functioning grafts at 6 months posttransplant, withdrawal patients had lower cholesterol (P = 0.0005), had higher creatinine (P = 0.03), and were less likely to use antihypertensives (P = 0.001). These differences persist to 1 yr posttransplant.

CONCLUSIONS

We conclude that for recipients on cyclosporine/mycophenolate mofetil/P with no AR at 90 days, the chance of developing subsequent AR is small; if P is tapered and withdrawn, the risk increases (but the majority remain free of acute and chronic rejection). After withdrawal, the risk of AR is different for blacks versus nonblacks. Withdrawal patients had a lower cholesterol level and less need for antihypertensives.

New strategies using 'low-dose' mycophenolate mofetil to reduce acute rejection in patients following kidney transplantation

CONTEXT

Tacrolimus, microemulsion cyclosporine (Neoral), and mycophenolate mofetil (MMF) at 2 and 3 grams daily have demonstrated superior immunosuppressive properties in several recent clinical trials involving solid-organ transplants. An effective immunosuppression may be maintained with lower doses of MMF administered with either tacrolimus or microemulsion cyclosporine.

OBJECTIVE

To compare tacrolimus plus "low-dose" MMF-based immunosuppressive regimen (TMBIR) with Neoral plus "low-dose" MMF-based immunosuppressive regimens (NMBIR) among kidney transplant recipients.

DESIGN

Prospective, randomized study.

PATIENTS

53 consecutive adult recipients of kidney transplant. Both groups (TMBIR and NMBIR) were equally matched on demographic characteristics.

INTERVENTIONS

Participants were randomized to receive orally either tacrolimus (0.08 mg/kg twice daily) (n = 27) or Neoral (4 mg/kg twice daily) (n = 26). Both regimens were started before surgery and continued when allograft demonstrated no postoperative acute tubular necrosis. Both groups received similar "low-dose" MMF (500 mg twice daily) and prednisone (2 mg/kg/day to taper off after 1 year). Switch from tacrolimus to Neoral or vice versa was allowed after refractory rejection or serious adverse events.

MAIN OUTCOME MEASURE

Acute rejection and patient and graft survival 1 year following kidney transplant.

RESULTS

One-year patient survival rates were 88.9% for the TMBIR group and 100% for the NMBIR group; 1-year graft survival rates were 88.9% for the TMBIR group and 96.1% for the NMBIR group. No significant differences were found in the incidence of biopsy-confirmed acute rejection (14.8% TMBIR vs 23% NMBIR). Steroid-resistant rejections requiring cytolytic antibody therapy were higher in the NMBIR group (50% vs 25%). Three patients crossed over from NMBIR to TMBIR for refractory rejections and 1 patient crossed over from TMBIR to NMBIR for new onset seizure. Three episodes of cytomegalovirus infection were observed in the TMBIR group. Other adverse events were similar in both groups.

CONCLUSIONS

Both tacrolimus and microemulsion cyclosporine combined with "low-dose" MMF and corticosteroids provide effective immunosuppression and have similar adverse events in kidney transplant recipients.

Pyrazinoylguanidine in end-stage renal disease: a prospective, placebo-controlled pilot study

Cardiovascular disease is the leading cause of mortality in end-stage renal disease (ESRD) patients receiving dialysis. In these patients, hypertriglyceridemia appears to increase the risk of accelerated atherosclerosis. The present placebo-controlled study evaluated prospectively lipid-lowering effects of pyrazinoylguanidine (PZG) in 6 ESRD patients undergoing maintenance hemodialysis. The design of the study entailed a placebo phase of 1 week followed by 3 weeks of PZG, 400 mg three times a day. Compared to placebo, PZG reduced serum triglycerides (PZG vs. placebo 370 +/- 171 vs. 414 +/- 182 mg/dl; p = 0.01). PZG also tended to decrease total cholesterol. In addition, PZG selectively lowered blood glucose in hyperglycemic patients. PZG was well tolerated; it did not interfere with hemodynamic parameters or alter liver function tests, nutritional parameters or dialysis clearance.

Immunopathogenesis of human immunodeficiency virus

Human immunodeficiency virus (HIV) types 1 and 2 infect cells of the immune system and initiate a robust immune response which counteracts the viral spread but also accelerates the destruction of the immune system. Many pathogenic mechanisms have been proposed which include viral gene products, syncytium formation, direct virus killing of cells, apoptosis, autoimmunity, cytokine and chemokine expression, superantigens, virus directed cell-mediated cytolysis, and disruption of the lymphoid architecture. At present, there is no unifying theory or experimental proof of a single or a predominant mechanism for the pathogenesis of the HIV disease. This review is intended to highlight areas of HIV research relevant to the understanding of HIV immunopathogenesis.