Congenital Partial Bronchial Atresia of Right Section Middle Lobe- A Rare Cause of Dyspnoea

Congenital Bronchial Atresia (CBA) is a rare congenital condition with features of focal obliteration of a proximal segment of a bronchus. Left upper lobe is the most commonly involved lobe. Authors hereby, present a case report of a 17-year-old male who presented with exertional dyspnoea, cough and chest pain. High Resolution Computed Tomography (HRCT) chest showed hyperventilated lung parenchyma with paucity of bronchovascular pattern in right middle lobe. Bronchoscopy revealed right middle lobe bronchial segmental atresia with rudimentary bronchus above that segment. The patient was treated with bronchodilators, steroids and improved symptomatically and advised surgical management. Patient was not willing for the same and hence managed conservatively. Though definite management for CBA is done surgically, medical management can be preferred for patients with mild symptoms and without recurrent infections.

Low-cost assays for monitoring HIV infected individuals in resource-limited settings

Use of a combination of CD4 counts and HIV viral load testing in the management of antiretroviral therapy (ART) provides higher prognostic estimation of the risk of disease progression than does the use of either test alone. The standard methods to monitor HIV infection are flow cytometry based for CD4+ T cell count and molecular assays to quantify plasma viral load of HIV. Commercial assays have been routinely used in developed countries to monitor ART. However, these assays require expensive equipment and reagents, well trained operators, and established laboratory infrastructure. These requirements restrict their use in resource-limited settings where people are most afflicted with the HIV-1 epidemic. With the advent of low-cost and/or low-tech alternatives, the possibility of implementing CD4 count and viral load testing in the management of ART in resource-limited settings is increasing. However, an appropriate validation should have been done before putting them to use for patient testing.

Establishment of reference CD4+ T cell values for adult Indian population

BACKGROUND

CD4+ T lymphocyte counts are the most important indicator of disease progression and success of antiretroviral treatment in HIV infection in resource limited settings. The nationwide reference range of CD4+ T lymphocytes was not available in India. This study was conducted to determine reference values of absolute CD4+ T cell counts and percentages for adult Indian population.

METHODS

A multicentric study was conducted involving eight sites across the country. A total of 1206 (approximately 150 per/centre) healthy participants were enrolled in the study. The ratio of male (N = 645) to female (N = 561) of 1.14:1. The healthy status of the participants was assessed by a pre-decided questionnaire. At all centers the CD4+ T cell count, percentages and absolute CD3+ T cell count and percentages were estimated using a single platform strategy and lyse no wash technique. The data was analyzed using the Statistical Package for the Social Scientist (SPSS), version 15) and Prism software version 5.

RESULTS

The absolute CD4+ T cell counts and percentages in female participants were significantly higher than the values obtained in male participants indicating the true difference in the CD4+ T cell subsets. The reference range for absolute CD4 count for Indian male population was 381-1565 cells/μL and for female population was 447-1846 cells/μL. The reference range for CD4% was 25-49% for male and 27-54% for female population. The reference values for CD3 counts were 776-2785 cells/μL for Indian male population and 826-2997 cells/μL for female population.

CONCLUSION

The study used stringent procedures for controlling the technical variation in the CD4 counts across the sites and thus could establish the robust national reference ranges for CD4 counts and percentages. These ranges will be helpful in staging the disease progression and monitoring antiretroviral therapy in HIV infection in India.

Impact of nitrate addition on biofilm properties and activities in rising main sewers

Anaerobic sewer biofilm is a composite of many different microbial populations, including sulfate reducing bacteria (SRB), methanogens and heterotrophic bacteria. Nitrate addition to sewers in an attempt to control hydrogen sulfide concentrations affects the behaviour of these populations, which in turn impacts on wastewater characteristics. Experiments were carried out on a laboratory reactor system simulating a rising main to determine the impact of nitrate addition on the microbial activities of anaerobic sewer biofilm. Nitrate was added to the start of the rising main during sewage pump cycles at a concentration of 30 mg-N L(-1) for over 5 months. While it reduced sulfide levels at the outlet of the system by 66%, nitrate was not toxic or inhibitory to SRB activity and did not affect the dominant SRB populations in the biofilm. Long-term nitrate addition in fact stimulated additional SRB activity in downstream biofilm. Nitrate addition also stimulated the activity of nitrate reducing, sulfide oxidizing bacteria that appeared to be primarily responsible for the prevention of sulfide build up in the wastewater in the presence of nitrate. A short adaptation period of three to four nitrate exposure events (approximately 10 h) was required to stimulate biological sulfide oxidation, beyond which no sulfide accumulation was observed under anoxic conditions. Nitrate addition effectively controlled methane concentrations in the wastewater. The nitrate uptake rate of the biofilm increased with repeated exposure to nitrate, which in turn increased the consumption of biodegradable COD in the wastewater. These results provide a comprehensive understanding of the impact of nitrate addition on wastewater composition and sewer biofilm microbial activities, which will facilitate optimization of nitrate dosing for effective sulfide control in rising main sewers.

Establishment of T-lymphocyte subset reference intervals in a healthy adult population in Chennai, India

Estimation of CD4+ T-lymphocytes continues to be an important aspect for monitoring HIV disease progression and response to antiretroviral therapy. Most of the diagnostic laboratories often rely on western text books for CD4+ T-lymphocyte reference values, which could, often be unreliable for usage in local settings. Therefore, we attempted to establish the reference values for T-lymphocyte subsets among healthy adults in a cross-sectional study carried out at the YRG Centre for AIDS Research and Education (YRG CARE) in Chennai, south India, in 213 (84 female and 129 male) healthy, HIV-1/2 seronegative adults as volunteers. Whole blood specimens were processed for CD4+, CD8+ T-lymphocyte estimation and haematological parameters. The established range of CD4+ T-lymphocyte counts for men and women were 383-1347 cells/microl (mean 865 and median 845 cells/microl) and 448-1593 cells/microl (mean 1021 and median 954 cells/microl), respectively. Women had significantly higher absolute CD4+ Tlymphocyte counts (P<0.001) and CD4+:CD8+ T-lymphocyte ratio as compared to men. The established normal range of CD4+ T-lymphocyte % was 21-59 (mean 40.2 and median 40.1). The influence of age was not observed in any of the parameters except CD4+/CD8+ T-lymphocyte ratio with the >45 yr age group. Further studies with greater sample size may be required to define the staging of HIV disease in relation to the normal CD4 T-lymphocyte count in the general population.

Nitrite effectively inhibits sulfide and methane production in a laboratory scale sewer reactor

The production and emission of hydrogen sulfide and methane by anaerobic microoganisms in sewer systems is a well-documented problem. The effectiveness of nitrite in controlling sulfide and methane production was tested in a laboratory scale sewer reactor. Nitrite was continuously dosed in the reactor for 25 days at concentrations of 20-140mgN/L. No sulfide and methane accumulation was observed in the reactor in the presence of nitrite. A significant reduction was observed in the sulfate reduction and methane production capabilities of the biofilm. Nitrite also stimulated biological sulfide oxidation within the biofilm. The nitrite uptake rate of the reactor increased over the nitrite dosing period and nitrous oxide production was observed within the biofilm. When nitrite addition was stopped, sulfate reduction and methane production gradually resumed, and reached pre-nitrite addition levels after 2.5 months. The slow recovery suggests that nitrite can be applied intermittently for sulfide and methane control, which represents a key advantage over similar chemicals such as nitrate and oxygen. The study demonstrates nitrite addition as a promising and effective strategy for the management of sulfide and methane in sewers. Further investigation and optimization are still required before application in the field.

Ethnic variation in certain hematological and biochemical reference intervals in a south Indian healthy adult population

BACKGROUND

We established the biochemical and hematological reference intervals among a south Indian healthy adult population attending an HIV referral centre in Chennai, southern India.

METHODS

In a cross sectional study, 213 study subjects (129 male and 84 female) were studied between March and August 2005. All of the parameters were analyzed using standard hematological and biochemical techniques.

RESULTS

Certain biochemical (viz. total bilirubin, alanine transaminase, albumin, creatinine, total protein, lipid profile, creatine phosphokinase, uric acid and lactate) and hematological (mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and lymphocyte levels) parameters presented higher upper limits. In addition, the upper limits of white blood cell count, platelet count, hematocrit, red blood cell count and hemoglobin level were low in comparison to the currently reported ranges.

CONCLUSION

Ethnic variation in reference intervals was observed in certain biochemical and hematological analytes in a south Indian adult population.

A Reliable and Inexpensive EasyCD4 Assay for Monitoring HIV-Infected Individuals in Resource-Limited Settings

Serial measurements of absolute CD4+ T-lymphocyte counts are required to initiate and gauge response to therapy and monitor disease progression. Hence, there is an urgent need to evaluate the accuracy and validity of low-cost CD4+ T-cell count assays. Tripotassium EDTA blood specimens from HIV-infected individuals were studied using a novel flow cytometric assay (EasyCD4 assay; Guava Technologies, Hayward, CA) in comparison with standard flow cytometry (FACSCount; Becton Dickinson Immunocytometry Systems, San Jose, CA). The sensitivity, specificity value by EasyCD4 assay in enumerating absolute CD4+ T-cell counts of less than 200 cells/microL were 95% and 100%, respectively. Bland-Altman analysis showed close agreement, with the EasyCD4 assay yielding CD4+ T-cell counts a mean difference of -26 cells/microL (95% confidence interval, -96 to 44 cells/microL) higher than by flow cytometry. Our data suggest that EasyCD4 assay could be a useful alternative assay to conventional flow cytometry, may be appropriate for use in resource-limited settings.