Sleep Quality and Daytime Sleepiness among Medical Undergraduate Students in Tamil Nadu: A Cross-sectional Study

Introduction: Sleep quality is strongly related to psychological and physical well-being. Medical students experience long duration of study period, academic over load, frequent exams, fear of failure and highly demanding lifestyle. They are vulnerable to poor sleep quality. Aim: To find the prevalence of sleep quality and daytime sleepiness and their associated factors among medical undergraduate students in Tamil Nadu, India. Materials and Methods: This was a cross-sectional study conducted among 367 undergraduate medical students from first year to final year of a Government Medical College, Chennai, Tamil Nadu, India. A self-administered questionnaire was used to collect data on socio-demographic characteristics, lifestyle behavioural factors, mobile phone usage and academic performance. Pittsburgh Sleep Quality Index (PSQI) and Epworth Daytime Sleepiness Scale (EDSS) were used to assess sleep quality and excessive daytime sleepiness, respectively. Descriptive statistics was used to express baseline characteristics. Chi-square test was be applied to test associated factor. Pearson correlation coefficient was used to find correlation between continuous variables. Results: Poor quality of sleep and excessive daytime sleepiness was found among 54.2% and 28.6% of students respectively. Poor sleep quality and excessive daytime sleepiness was significantly associated with increased duration of mobile phone usage (p=0.030 and p=0.009 respectively). Significant association was found between sleep quality and academic performance (p=0.004). Statistically significant correlation was found between sleep quality and duration of mobile phone usage (r=0.18, p=0.0001) as well as sleep quality and excessive daytime sleepiness (r=0.14, p=0.005). Conclusion: Prevalence of poor quality sleep and excessive daytime sleepiness was found to be high among medical students. Mobile phone overuse was significantly associated with poor sleep quality and excessive daytime sleepiness. Students with good quality of sleep had better academic performance when compared to poor sleepers. Excessive daytime sleepiness was found in increasing pattern among those with poor quality sleep

Hierarchal Bayes model with AlexNet for characterization of M-FISH chromosome images

The analysis of chromosomes is a significant and challenging task for clinical diagnosis and biological research. The technique based on color imaging is a multiplex fluorescent in situ hybridization (M-FISH), which was implemented to ease the exploration of the chromosomes. Thus, in this paper, we propose a novel quasi-Newton-based K-means clustering for the M-FISH image segmentation. Then, we use the expectation-maximization-based hierarchical Bayes model to characterize the M-FISH images. The contextual-based classification and region merging of chromosomal images is made to avoid any misclassification, and we made use of AlexNet, by modifying the activation functions of the sigmoid and softmax layer and for the optimum classification between the autosomal chromosomes and the sex chromosome. Finally, we conducted a performance analysis by measuring accuracy, recall, sensitivity, specificity, PPV, NPV, F-score, kappa, Jaccard, and Dice coefficient and compared with other existing methods and found that our proposed methodology can achieve more percentage of accuracy (6.96%) than the state of the art methods.

Lifestyle Behaviour among Undergraduate Medical Students in Tamil Nadu: A Cross-sectional Study

Introduction: Lifestyle related behavioural risk factors such as physical inactivity and nutrition transition like increased consumption of high‑fat and low‑fiber diet are found to be risk factors for Non Communicable Diseases (NCD) worldwide. Medical students are susceptible to poor eating habits, physical inactivity, lack of sleep or acquisition of new habits, such as smoking and alcohol. They have been shown to exhibit early risk factors for chronic diseases. Hence, it is essential to assess the lifestyle behaviour among medical students as they are future healthcare providers. Aim: To assess the lifestyle behaviour among the undergraduate medical students and to compare lifestyle behavioural factors between gender. Materials and Methods: A cross‑sectional study was conducted among 200 undergraduate medical students, selected by using random sampling method from first year to final year of a government medical college in Chennai, Tamil Nadu from June 2018 to August 2018. Self‑administered questionnaire was used to collect data regarding socio‑demographic profile and lifestyle behaviours such as dietary pattern, physical activity, sedentary behaviour, sleep duration, smoking and alcohol consumption. Descriptive statistics for qualitative data and Chi‑square test to test the proportions were used. Results: A total of 200 undergraduate medical students participated in the study. The mean age of the study participants was 20.2 years with a standard deviation of 1.34. Out of the 200 study participants, 132 (66%) were females and 68 (34%) were males. Skipping of meals was seen in 54% students. Vegetables and fruits intake ≤3 times/week were found in 25.5% and 63% students respectively. Smoking was observed in 3% and alcohol intake in 7.5% students. Lack of exercise was noted in 46%. Television viewing/mobile usage for >4 hours per day was observed in 30.5% students. Sleep duration of <6 hours/day was noted in 11%. Frequent carbonated drinks consumption (>3 times/week) was significantly higher in males (14.7%) as compared to females (5.3%). Inadequate exercise was significantly higher in females. Conclusion: Behavioural risk factors such as unhealthy diet, irregular eating habits, and physical inactivity were prevalent among the medical undergraduate students.

Standardisation of Rhenium-188 and determination of calibration factors for secondary standard and radionuclide calibrator

The use of Rhenium-188 for various therapeutic applications in the field of nuclear medicine has increased in recent years due to its favourable properties like decay scheme, cost effective availability and easy chemistry. Two independent measuring setups were used to standardise ¹⁸⁸Re radioactive solution. The modus operandi of standardisation was 4πβ-γ coincidence technique where the beta detection was done by proportional counting and liquid scintillation counting and the gamma detection was done by using NaI(Tl) detectors. The secondary standard, high pressure ionisation chamber type Centronic IG12, 20A was calibrated with the standardised ¹⁸⁸Re solution and the sensitivity coefficient (pA MBq^-1) was determined. To enhance the accuracy of the commercial radionuclide calibrator and to ensure that patients receive optimum dose of these radiopharmaceuticals, calibration number of the Capintec CRC-15β radionuclide calibrator was also verified. This paper presents the standardisation of ¹⁸⁸Re radioactive solution by primary methods and calibration of BARC secondary standard ionisation chamber system and a Capintec CRC-15β radionuclide calibrator.

Malnutrition is associated with diminished baseline and mycobacterial antigen - stimulated chemokine responses in latent tuberculosis infection

OBJECTIVES

Previous studies have demonstrated a diminution in the baseline and mycobacterial antigen - specific cytokines in low body mass index (LBMI) individuals with latent tuberculosis infection (LTBI). We hypothesized that LBMI might be also associated with alteration in the baseline and antigen - stimulated levels of chemokines in LTBI.

METHODS

To test this hypothesis, we examined baseline, TB-antigen and mitogen stimulated levels of chemokines in these individuals and compared them with those with LTBI and normal BMI (NBMI).

RESULTS

LBMI with LTBI is characterized by diminished baseline levels of CCL1, CCL4, CCL11, CXCL1, CXCL9, CXCL10 and CXCL11 in comparison to NBMI with LTBI. Similarly, LTBI with LBMI is also characterized by diminished TB-antigen stimulated levels of CCL1, CCL2, CCL3, CCL4, CCL11, CXCL1, CXCL2, CXCL9, CXCL10 and CXCL11. In contrast, there were no significant differences in the mitogen stimulated chemokine levels between the groups. Finally, there was a significant positive correlation between BMI and CCL1, CCL4, CCL11, CXCL11, CXCL2, CXCL9 and CXCL11 levels in LTBI individuals.

CONCLUSIONS

Therefore, our data reveal that LTBI subjects with low BMI are characterized by diminished levels of a variety of important chemokines, providing a novel biological mechanism for the increased risk of developing active TB.

Corrosion resistance of BIS 2062-grade steel coated with nano-metal-oxide mixtures of iron, cerium, and titanium in the marine environment

BIS 2062-grade carbon steel is extensively used for fishing boat construction. The steel is highly susceptible to corrosion on the hull and welding joints under marine environment. Here, we demonstrate the application of a novel multifunctional nano-metal-oxide mixture comprised of iron, titanium, and cerium as a marine coating to prevent corrosion. The electrochemical performance of nano-metal-oxide mixture coatings, applied over boat-building steel, was evaluated at 3.5% NaCl medium. The nano-mixture surface coatings showed an efficient corrosion resistance with increased polarization resistance of 6043 Ω cm2 and low corrosion current density of 3.53 × 10−6 A cm−2. The electrochemical impedance spectral data exhibited improvement in the polarization resistance of outermost surface and internal layers. The coating responded faster recovery to normal state when subjected to an induced stress over the coating. The nano-material in the coating behaves as a semiconductor; this enhanced electronic activity over the surface of the steel.

Successful multi-modal treatment of grade IV lymphedema in lymphatic filariasis: A case study

We present an integrated therapeutic approach performed on a 37 year old female with giant lymphedema (Grade IV) due to lymphatic filariasis of 27 years duration. Our therapeutic approaches consisted of a basic foot care program for two weeks, followed by a course of oral penicillin for a week including conservative treatment with complete decongestive therapy (CDT) together with respiratory physiotherapy and walking exercises. In addition, advanced surgical techniques with supra-fascial excision of alternate lumps in three stages over an interval of ten days followed by a nodo-venal shunt resulted in reversing the stage IV lymphedema condition. Over a ten year follow-up, the patient remains essentially unchanged confirming the success of the treatment without any recurrence or complications. Finally, by combining multimodal treatment, we were able to achieve a near normal limb in Stage III and Stage IV lymphedema of the lower limb in lymphatic filariasis.

Modulation of CD4+ and CD8+ T Cell Function and Cytokine Responses in Strongyloides stercoralis Infection by Interleukin-27 (IL-27) and IL-37

Strongyloides stercoralis infection is associated with diminished antigen-specific Th1- and Th17-associated responses and enhanced Th2-associated responses. Interleukin-27 (IL-27) and IL-37 are two known anti-inflammatory cytokines that are highly expressed in S. stercoralis infection. We therefore wanted to examine the role of IL-27 and IL-37 in regulating CD4+ and CD8+ T cell responses in S. stercoralis infection. To this end, we examined the frequency of Th1/Tc1, Th2/Tc2, Th9/Tc9, Th17/Tc17, and Th22/Tc22 cells in 15 S. stercoralis-infected individuals and 10 uninfected individuals stimulated with parasite antigen following IL-27 or IL-37 neutralization. We also examined the production of prototypical type 1, type 2, type 9, type 17, and type 22 cytokines in the whole-blood supernatants. Our data reveal that IL-27 or IL-37 neutralization resulted in significantly enhanced frequencies of Th1/Tc1, Th2/Tc2, Th17/Tc17, Th9, and Th22 cells with parasite antigen stimulation. There was no induction of any T cell response in uninfected individuals following parasite antigen stimulation and IL-27 or IL-37 neutralization. Moreover, we also observed increased production of gamma interferon (IFN-γ), IL-5, IL-9, IL-17, and IL-22 and decreased production of IL-10 following IL-27 and IL-37 neutralization and parasite antigen stimulation in whole-blood cultures. Thus, we demonstrate that IL-27 and IL-37 limit the induction of particular T cell subsets along with cytokine responses in S. stercoralis infections, which suggest the importance of IL-27 and IL-37 in immune modulation in a chronic helminth infection.

Modulation of Mycobacterium tuberculosis-specific humoral immune responses is associated with Strongyloides stercoralis co-infection

Background / Objectives

Helminth infections are known to influence T cell responses in latent tuberculosis (LTBI). Whether helminth infections also modulate B cell responses in helminth-tuberculosis co-infection is not known.

Methods

We assessed Mycobacterium tuberculosis (Mtb)–antigen specific IgM and IgG levels, circulating levels of the B cell growth factors, BAFF and APRIL and the absolute numbers of the various B cell subsets in individuals with LTBI, LTBI with coincident Strongyloides stercoralis (Ss) infection (LTBI/Ss) and in those with Ss infection alone (Ss). We also measured the above-mentioned parameters in the LTBI-Ss group after anthelmintic therapy.

Results

Our data reveal that LTBI-Ss exhibit significantly diminished levels of Mtb-specific IgM and IgG, BAFF and APRIL levels in comparison to those with LTBI. Similarly, those with LTBI-Ss had significantly diminished numbers of all B cell subsets (naïve, immature, classical memory, activated memory, atypical memory and plasma cells) compared to those with LTBI. There was a positive correlation between Mtb—antigen specific IgM and IgG levels and BAFF and APRIL levels that were in turn related to the numbers of activated memory B cells, atypical memory B cells and plasma cells. Finally, anthelmintic treatment resulted in significantly increased levels of Mtb—antigen specific IgM and IgG levels and the numbers of each of the B cell subsets.

Conclusions

Our data, therefore, reveal that Ss infection is associated with significant modulation of Mtb-specific antibody responses, the levels of B cell growth factors and the numbers of B cells (and their component subsets).

Helminth infections and tuberculosis are two of the major health care problems worldwide and share a great deal of geographical overlap. Moreover, helminth infections are known to induce immune responses that are antagonistic to the protective immune responses elicited by Mycobacterium tuberculosis. Having previously demonstrated that helminth infections can profoundly alter protective T cell responses needed to control tuberculosis infection, we examined how Strongyloides stercoralis (Ss) infection influences B cell responses in latent tuberculosis infection (LTBI) in the context of co-infection and showed the Ss infection is associated with dramatic alterations in mycobacterial-specific IgG and IgM responses and levels of B cells and their growth factors BAFF and APRIL. These alterations in B cell responses could have implications for vaccine-induced immune responses to tuberculosis in helminth—endemic countries.

Stress and Stressors among Medical Undergraduate Students: A Cross-sectional Study in a Private Medical College in Tamil Nadu

Background:

Medical education is perceived as being stressful, and a high level of stress may have a negative effect on cognitive functioning and learning of students in a medical school.

Objectives:

To (a) assess the perceived stress among medical undergraduate students, (b) identify the sources of stress, and (c) find an association of perceived stress with sociodemographic characteristics and various stressors.

Materials and Methods:

A cross-sectional study was conducted among medical undergraduate students in a private medical college in Tamil Nadu. A total of 750 medical students from 1^st year to final year were invited to participate in the study. Self-administered questionnaire was used to collect data regarding sociodemographic profile, perceived stress using perceived stress scale-14 and academic, psychosocial and environmental stressors. Descriptive statistics was used to describe the sociodemographic characteristics, sources of stress and perceived stress. Logistic regression analyses were carried out to assess determinants of stress.

Results:

The overall response rate was 93.33% (700 out of 750 students). The mean perceived stress score was 25.64 ± 5.44. Higher age-group, year of studying bachelor of medicine and bachelor of surgery, vastness of academic curriculum, fear of poor performance in examination, lack of recreation, loneliness, family problem, and accommodation away from home were important determinants of perceived stress.

Conclusions:

The perceived stress was higher among higher age group and final year medical students. Academic, psychosocial, and environmental stressors are associated with perceived stress. Reframing the academic curriculum and examination patterns, incorporating recreational and sports activities, and establishment of counseling cells in the institution is needed.

An overview of lymphatic filariasis lymphedema

Filariasis is caused by thread-like nematode worms and is classified according to their presence in the vertebrate host. The lymphatic group includes Wuchereria bancrofti, Brugia malayi, and Brugia timori. Lymphatic filariasis, a mosquito-borne disease, has been one of the most prevalent diseases in tropical and subtropical countries and is accompanied by a number of pathological conditions. It is estimated that currently (after 13 years of the MDA programme) there are an estimated 67.88 million LF cases that include 36.45 million microfilaria carriers, 19.43 million hydrocele cases, and 16.68 million lymphedema cases. Adult filarial worms reside in the lymphatics and lymph nodes and induce changes that result in dilatation of lymphatics and thickening of the lymphatic vessel walls. Progressive lymphatic damage and pathology results from the summation of the effect of tissue alterations induced by both living and nonliving adult parasites. In recent years, there has been rapid progress in filariasis research, which has provided new insights into the pathogenesis of filarial disease, diagnosis, chemotherapy, the host-parasite relationship, and the genomics of the parasite. We examined the clinical manifestations of the disease, diagnosis, treatment, immune responses, and management including review of pharmaceutical agents against filariasis. Details on infection, safety profile, and status in clinical practices are also reported.

Role of Community in Swachh Bharat Mission. Their Knowledge, Attitude and Practices of Sanitary Latrine Usage in Rural Areas, Tamil Nadu

BACKGROUND

In most developing countries, open defecation is the 'way of life'. This practice is considered as the most serious health and environmental hazard. Prime Minister of India launched the "Swachh Bharat Mission" to accelerate the efforts for achieving universal sanitation coverage and to put focus on sanitation.

OBJECTIVE

To find the knowledge, attitude and practices of sanitary latrines usage in rural area, Tamil Nadu.

MATERIALS AND METHODS

This was a cross sectional study conducted among rural population in Kuthambakkam village, Tamil Nadu. There were a total of 1175 households in Kuthambakkam village. These households were serially numbered and of these a sample of 275 households were selected for the study using simple random sampling technique by lottery method. A structured questionnaire was used to collect information regarding the background characteristics, their knowledge, attitude and practices towards sanitary latrines usage. Descriptive statistics were calculated for background variables, the prevalence of sanitary latrines usage and open air defecation. Association between factors responsible for open air defecation was found by using chi square test.

RESULTS

The prevalence of usage of household sanitary latrine and community latrines was 62.5% and 4.3% respectively. The prevalence of open air defecation among the study participants was 33.1%.Significant association was found between low standard of living and open air defecation practice.

CONCLUSIONS

To solve the problem of underutilization of sanitary latrines, planning and conducting Information Education Communication activities is very essential. Effective political and administrative support is needed to scale up the sanitation program.

High body mass index is associated with heightened systemic and mycobacterial antigen - Specific pro-inflammatory cytokines in latent tuberculosis

High body mass index (HBMI) has been shown to be protective against active tuberculosis (TB), although the biological mechanism underlying this protection is poorly understood. The immunological association between HBMI and latent TB has never been examined. In order to study the association of HBMI with latent TB, we examined the circulating and TB- antigen or mitogen stimulated levels of a large panel of cytokines in individuals with latent TB (LTB) and high or normal body mass index (HBMI or NBMI). HBMI is characterized by heightened circulating levels of pro-inflammatory (IFNγ, TNFα, IL-22, IL-1α, IL-12 and GM-CSF) cytokines but decreased circulating levels of anti-inflammatory cytokines (IL-4, IL-5 and TGFβ). This systemic cytokine profile is associated with elevated TB-antigen and mitogen stimulated levels of IFNγ, TNFα, IL-2 and IL-1α and diminished levels of IL-10 and TGFβ. In addition, we also observed a positive correlation between the circulating levels of IFNγ, TNFα, IL-22, IL-1α with BMI and a negative correlation between the circulating levels of IL-10, TGFβ and BMI. Our data, therefore, suggest the modulation of protective and regulatory cytokines might underlie the protective effect of HBMI against the development of active TB.

IL-10- and TGFβ-mediated Th9 Responses in a Human Helminth Infection

Background

Th9 cells are a subset of CD4⁺ T cells that express the protoypical cytokine, IL-9. Th9 cells are known to effect protective immunity in animal models of intestinal helminth infections. However, the role of Th9 cells in human intestinal helminth infections has never been examined.

Methodology

To examine the role of Th9 cells in Strongyloidis stercoralis (Ss), a common intestinal helminth infection, we compared the frequency of Th9 expressing IL-9 either singly (mono-functional) or co-expressing IL-4 or IL-10 (dual-functional) in Ss-infected individuals (INF) to frequencies in uninfected (UN) individuals.

Principal Findings

INF individuals exhibited a significant increase in the spontaneously expressed and/or antigen specific frequencies of both mono- and dual-functional Th9 cells as well as Th2 cells expressing IL-9 compared to UN. The differences in Th9 induction between INF and UN individuals was predominantly antigen-specific as the differences were no longer seen following control antigen or mitogen stimulation. In addition, the increased frequency of Th9 cells in response to parasite antigens was dependent on IL-10 and TGFx since neutralization of either of these cytokines resulted in diminished Th9 frequencies. Finally, following successful treatment of Ss infection, the frequencies of antigen-specific Th9 cells diminished in INF individuals, suggesting a role for the Th9 response in active Ss infection. Moreover, IL-9 levels in whole blood culture supernatants following Ss antigen stimulation were higher in INF compared to UN individuals.

Conclusion

Thus, Ss infection is characterized by an IL-10- and TGFβ dependent expansion of Th9 cells, an expansion found to reversible by anti-helmintic treatment.

Strongyloides stercoralis is a common intestinal parasite affecting about 50–100 million people worldwide. It is characterized by a complex lifecycle involving both free- living and parasitic stages and the clinical manifestations range from asymptomatic infection to multi-organ failure. It has the propensity to cause disseminated disease and death in immunocompromised individuals. Therefore, an in depth understanding of the immune responses to this helminth parasite is warranted. However, what we know about the immunity to this infection is mostly derived from animal studies. Th9 cells are a subset of CD4+ T cells producing the cytokine—IL-9. Since Th9 cells are increasingly recognized as being important in immunity to intestinal infection with helminths, we examined the induction and regulation Th9 cell responses to Ss infection utilizing infected and uninfected individuals from an endemic area in India. We show that Ss infection is characterized by profound alterations in the Th9 compartment and that this response is mainly regulated by the cytokines—IL-10 and TGFβ. In addition, we also demonstrate that active infection is a pre-requisite for this regulation and anti-Ss treatment can dampen enhanced Th9 responses.

Performance demonstration of 4πβ(LS)-γ coincidence counting system for standardization of radionuclides with complex decay scheme

A standardization of (134)Cs and (131)I was carried out in order to demonstrate the performance and applicability of the 4πβ(LS)-γ coincidence counting system for standardization of radionuclides with complex decay scheme. The coincidence analyzer, capable of analyzing coincidence between beta and two gamma windows simultaneously, was developed and used for the standardization. The use of this dual coincidence analyzer has reduced the total experimental time by half. The activity concentrations obtained using the 4πβ(LS)-γ coincidence counting system, a 4πβ(PC)-γ coincidence counting system, and the CIEMAT/NIST method are in excellent agreement with each other within uncertainty limits and hence demonstrates its performance for standardization of radionuclides decaying with complex decay scheme. Hence use of this 4πβ(LS)-γ coincidence counting system can be an alternative method suitable to standardize radionuclides with complex decay scheme with acceptable precision.

Denture bar-coding: An innovative technique in forensic dentistry

Denture markers play an important role in forensic odontology and also in identifying a person. A number of methods are there for identifying dentures from a less expensive technique to a more expensive technique. Out of different denture markers, the bar-coding system is a way of collecting data from the mobile. Even a huge amount of data can be stored in that. It can be easily incorporated during acrylization of the denture and thus could be helpful in identification. This article reviews the strengths of bar-coding and how easily it can be used in the routine procedure.

Modulation of CD4+ and CD8+ T-Cell Function by Interleukin 19 and Interleukin 24 During Filarial Infections

Interleukin 19 (IL-19) and interleukin 24 (IL-24) are cytokines that are highly expressed in filarial infections. To study the role of IL-19 and IL-24 in regulating T-cell responses, we examined the frequency of T-helper type 1 (Th1)/Tc1, Th2/Tc2, Th9/Tc9, Th17/Tc17, Th22/Tc22, and Tr1 cells in 26 filariae-infected individuals stimulated with filarial antigen following IL-19 or IL-24 neutralization. IL-19 or IL-24 neutralization resulted in significantly enhanced frequencies of Th1/Tc1 and/or Th17/Tc17 cells and significantly reduced frequencies of Th2/Tc2, Tr1, and/or Th9/Tc9 cells. Thus, we demonstrate that IL-19 and IL-24 are associated with the modulation of T-cell responses in filarial infections.

Parasite Antigen-Specific Regulation of Th1, Th2, and Th17 Responses in Strongyloides stercoralis Infection

Chronic helminth infections are known to be associated with modulation of Ag-specific CD4(+) T responses. However, the role of CD4(+) T cell responses in human infection with Strongyloides stercoralis is not well defined. To examine the role of CD4(+) T cells expressing Th1, Th2, and Th17 cytokines in strongyloidiasis, we compared the frequency (Fo) of these subsets in infected (INF) individuals with Fo in S. stercoralis-uninfected (UN) individuals. INF individuals exhibited a significant decrease in the spontaneous and Ag-specific Fo of both monofunctional and dual-functional Th1 cells compared with UN. Similarly, INF individuals also exhibited significantly decreased Fo of monofunctional and dual-functional Th17 cells upon Ag stimulation compared with UN. In contrast, both the spontaneous and the Ag-induced Fo of monofunctional and dual-functional Th2 cells was significantly increased in INF compared with UN individuals. This differential T cell response was predominantly Ag specific because it was abrogated upon control Ag or mitogen stimulation. The regulation of Th1, Th2, and Th17 cells was predominantly dependent on IL-10, whereas the regulation of Th2, but not Th1 or Th17, cells was also dependent on TGF-β. In addition, treatment of S. stercoralis infection significantly increased the Ag-specific Fo of Th1 and Th17 cells and decreased the Fo of Th2 cells in INF individuals. Thus, S. stercoralis infection is characterized by a parasite Ag-dependent regulation of monofunctional and dual-functional Th1, Th2, and Th17 cells, a regulation also reversible by antihelminthic treatment.

Helminth infections coincident with active pulmonary tuberculosis inhibit mono- and multifunctional CD4+ and CD8+ T cell responses in a process dependent on IL-10

Tissue invasive helminth infections and tuberculosis (TB) are co-endemic in many parts of the world and can trigger immune responses that might antagonize each other. We have previously shown that helminth infections modulate the Th1 and Th17 responses to mycobacterial-antigens in latent TB. To determine whether helminth infections modulate antigen-specific and non-specific immune responses in active pulmonary TB, we examined CD4⁺ and CD8⁺ T cell responses as well as the systemic (plasma) cytokine levels in individuals with pulmonary TB with or without two distinct helminth infections—Wuchereria bancrofti and Strongyloides stercoralis infection. By analyzing the frequencies of Th1 and Th17 CD4⁺ and CD8⁺ T cells and their component subsets (including multifunctional cells), we report a significant diminution in the mycobacterial–specific frequencies of mono- and multi–functional CD4⁺ Th1 and (to a lesser extent) Th17 cells when concomitant filarial or Strongyloides infection occurs. The impairment in CD4⁺ and CD8⁺ T cell cytokine responses was antigen-specific as polyclonal activated T cell frequencies were equivalent irrespective of helminth infection status. This diminution in T cell responses was also reflected in diminished circulating levels of Th1 (IFN-γ, TNF-α and IL-2)- and Th17 (IL-17A and IL-17F)-associated cytokines. Finally, we demonstrate that for the filarial co-infections at least, this diminished frequency of multifunctional CD4⁺ T cell responses was partially dependent on IL-10 as IL-10 blockade significantly increased the frequencies of CD4⁺ Th1 cells. Thus, co-existent helminth infection is associated with an IL-10 mediated (for filarial infection) profound inhibition of antigen-specific CD4⁺ T cell responses as well as protective systemic cytokine responses in active pulmonary TB.

While it has long been recognized that helminth infections alter the pathophysiology of allergic and autoimmune disease, data suggest that helminth infections also exert an important immunological effect on concomitant infections and vaccine responses. In particular, helminth coinfection can modulate the severity, pathogenesis and transmission of other infectious diseases. In this study, we examine the mechanism by which helminth infections modulate the immunological responses to tuberculosis antigens in individuals with active pulmonary tuberculosis. Our data suggest that two different helminth infections, with different life cycles, tissue localization and modes of transmission essentially exert very similar effects on the adaptive immune response to tuberculosis antigens in pulmonary tuberculosis. This includes a compromised induction of protective cytokine-expressing T cells as well as inhibitory effects on systemic cytokines that are potentially protective in tuberculosis. The strength of this study lies in the fact that this is the first study to demonstrate that two different helminth infections essentially impair cytokine responses in a similar manner in pulmonary tuberculosis.

Expansion of parasite-specific CD4+ and CD8+ T cells expressing IL-10 superfamily cytokine members and their regulation in human lymphatic filariasis

BACKGROUND

Lymphatic filariasis (LF) is known to be associated with an increased production of IL-10. The role of the other IL-10 family members in the pathogenesis of infection and/or disease is not known.

METHODOLOGY/PRINCIPAL FINDINGS

We examined the expression patterns of IL-10 family members--IL-19, IL-24 and IL-26 in LF. We demonstrate that both CD4+ and CD8+ T cells express IL-19, IL-24 and IL-26 and that the frequency of CD4+ T cells expressing IL-19 and IL-24 (as well as IL-10) is significantly increased at baseline and following filarial antigen stimulation in patients with LF in comparison to individuals with filarial lymphedema and uninfected individuals. This CD4+ T cell expression pattern was associated with increased production of IL-19 and IL-24 by filarial-antigen stimulated PBMC. Moreover, the frequency of CD4+ and CD8+ T cells expressing IL-26 was significantly increased following filarial antigen stimulation in filarial lymphedema individuals. Interestingly, IL-10 blockade resulted in diminished frequencies of IL-19+ and IL-24+ T cells, whereas the addition of recombinant IL-10 resulted in significantly increased frequency of IL-19+ and IL-24+ T cells as well as significantly up regulated IL-19 and IL-24 gene expression, suggesting that IL-10 regulates IL-19 and IL-24 expression in T cells. In addition, IL-1β and IL-23 blockade also induced a diminution in the frequency of IL-19+ and IL-24+ T cells, indicating a novel role for these cytokines in the induction of IL-19 and IL-24 expressing T cells. Finally, elimination of infection resulted in significantly decreased frequencies of antigen - specific CD4+ T cells expressing IL-10, IL-19 and IL-24.

CONCLUSIONS

Our findings, therefore, suggest that IL-19 and IL-24 are associated with the regulation of immune responses in active filarial infection and potentially with protection against development of pathology, while IL-26 is predominantly associated with pathology in LF.

Parasite-antigen driven expansion of IL-5(-) and IL-5(+) Th2 human subpopulations in lymphatic filariasis and their differential dependence on IL-10 and TGFβ

Background

Two different Th2 subsets have been defined recently on the basis of IL-5 expression – an IL-5⁺Th2 subset and an IL-5⁻Th2 subset in the setting of allergy. However, the role of these newly described CD4⁺ T cells subpopulations has not been explored in other contexts.

Methods

To study the role of the Th2 subpopulation in a chronic, tissue invasive parasitic infection (lymphatic filariasis), we examined the frequency of IL-5⁺IL-4⁺IL-13⁺ CD4⁺ T cells and IL-5⁻IL-4 IL-13⁺ CD4⁺ T cells in asymptomatic, infected individuals (INF) and compared them to frequencies (F_o) in filarial-uninfected (UN) individuals and to those with filarial lymphedema (CP).

Results

INF individuals exhibited a significant increase in the spontaneously expressed and antigen-induced F_o of both Th2 subpopulations compared to the UN and CP. Interestingly, there was a positive correlation between the F_o of IL-5⁺Th2 cells and the absolute eosinophil and neutrophil counts; in addition there was a positive correlation between the frequency of the CD4⁺IL-5⁻Th2 subpopulation and the levels of parasite antigen – specific IgE and IgG4 in INF individuals. Moreover, blockade of IL-10 and/or TGFβ demonstrated that each of these 2 regulatory cytokines exert opposite effects on the different Th2 subsets. Finally, in those INF individuals cured of infection by anti-filarial therapy, there was a significantly decreased F_o of both Th2 subsets.

Conclusions

Our findings suggest that both IL-5⁺ and IL-5⁻Th2 cells play an important role in the regulation of immune responses in filarial infection and that these two Th2 subpopulations may be regulated by different cytokine-receptor mediated processes.

Th2 cells are CD4⁺ T cells that produce a unique set of cytokines - IL-4, IL-5 and IL-13. Th2 cells are commonly associated with allergies, asthma and helminth infections. A common helminth infection that infects over 120 million people worldwide is lymphatic filarial infection caused by filarial parasites. We show here data that filarial infection is associated with the expansion of two types of Th2 cells, one which produces IL-4 and IL-13 alone without IL-5 and the other which produces all three cytokines. Interestingly, while the former subset is associated with the levels of antibodies - IgG4 and IgE; the latter is associated with the presence of eosinophilia in filarial infected individuals. In addition, these subsets appear to be modulated differently by the immunoregulatory cytokines - IL-10 and TGFβ. Therefore, our study highlights a novel regulation of Th2 cells and suggests that the Th2 compartment is quite heterogeneous in phenotype with possible functional consequences.

IL-4-, TGF-β-, and IL-1-dependent expansion of parasite antigen-specific Th9 cells is associated with clinical pathology in human lymphatic filariasis

Th9 cells are a subset of CD4(+) T cells, shown to be important in allergy, autoimmunity, and antitumor responses; however, their role in human infectious diseases has not been explored in detail. We identified a population of IL-9 and IL-10 coexpressing cells (lacking IL-4 expression) in normal individuals. These cells respond to antigenic and mitogenic stimulation, but are distinct from IL-9(+) Th2 cells. We also demonstrate that these Th9 cells exhibit Ag-specific expansion in a chronic helminth infection (lymphatic filariasis). Comparison of Th9 responses reveals that individuals with pathology associated with filarial infection exhibit significantly expanded frequencies of filarial Ag-induced Th9 cells, but not of IL9(+)Th2 cells in comparison with filarial-infected individuals without associated disease. Moreover, the per cell production of IL-9 is significantly higher in Th9 cells compared with IL9(+)Th2 cells, indicating that the Th9 cells are the predominant CD4(+) T cell subset producing IL-9 in the context of human infection. This expansion was reflected in elevated Ag-stimulated IL-9 cytokine levels in whole blood culture supernatants. Finally, the frequencies of Th9 cells correlated positively with the severity of lymphedema (and presumed inflammation) in filarial-diseased individuals. This expansion of Th9 cells was dependent on IL-4, TGF-β, and IL-1 in vitro. We have therefore identified an important human CD4(+) T cell subpopulation coexpressing IL-9 and IL-10, but not IL-4, the expansion of which is associated with disease in chronic lymphatic filariasis and could potentially have an important role in the pathogenesis of other inflammatory disorders.

Modulation of mycobacterial-specific Th1 and Th17 cells in latent tuberculosis by coincident hookworm infection

Hookworm infections and tuberculosis (TB) are coendemic in many parts of the world. It has been suggested that infection with helminth parasites could suppress the predominant Th1 (IFN-γ-mediated) response needed to control Mycobacterium tuberculosis infection and enhance susceptibility to infection and/or disease. To determine the role of coincident hookworm infection on responses at steady-state and on M. tuberculosis-specific immune responses in latent TB (LTB), we examined the cellular responses in individuals with LTB with or without concomitant hookworm infection. By analyzing the expression of Th1, Th2, and Th17 subsets of CD4(+) T cells, we were able to demonstrate that the presence of coincident hookworm infection significantly diminished both spontaneously expressed and M. tuberculosis-specific mono- and dual-functional Th1 and Th17 cells. Hookworm infection, in contrast, was associated with expanded frequencies of mono- and dual-functional Th2 cells at both steady-state and upon Ag stimulation. This differential induction of CD4(+) T cell subsets was abrogated upon mitogen stimulation. Additionally, coincident hookworm infection was associated with increased adaptive T regulatory cells but not natural regulatory T cells in LTB. Finally, the CD4(+) T cell cytokine expression pattern was also associated with alterations in the systemic levels of Th1 and Th2 cytokines. Thus, coincident hookworm infection exerts a profound inhibitory effect on protective Th1 and Th17 responses in LTB and may predispose toward the development of active tuberculosis in humans.

Development of liquid scintillation based 4πβ(LS)-γ coincidence counting system and demonstration of its performance by standardization of ⁶⁰Co

A single-vial, single-PMT 4πβ(LS)-γ coincidence counting system has been developed at the Radiation Safety Systems Division, BARC. It has advantages of simple sample preparation, higher counting efficiency and the absence of self absorption over the conventional proportional counter based 4πβ(PC)-γ coincidence counting system. The performance of the system is demonstrated by standardizing a (60)Co solution using the 4πβ(LS)-γ coincidence counting system, 4πβ(PC)-γ coincidence counting system and CIEMAT/NIST method and comparing the results obtained by each method. The detection efficiency of liquid scintillation counter of the 4πβ(LS)-γ coincidence counting system was varied by color quenching, by chemical quenching and by varying the bias voltage applied to the LSC PMT. For the proportional counter based 4πβ(PC)-γ coincidence counting system the detection efficiency was varied by source self absorption. The activity concentrations obtained using the 4πβ(LS)-γ coincidence counting system, the 4πβ(PC)-γ coincidence counting system and the CIEMAT/NIST method are comparable within the uncertainty limits.

Evidence of microbial translocation associated with perturbations in T cell and antigen-presenting cell homeostasis in hookworm infections

Background

Microbial translocation (MT) is the process by which microbes or microbial products translocate from the intestine to the systemic circulation. MT is a common cause of systemic immune activation in HIV infection and is associated with reduced frequencies of CD4⁺ T cells; no data exist, however, on the role of MT in intestinal helminth infections.

Methods

We measured the plasma levels of MT markers, acute-phase proteins, and pro- and anti - inflammatory cytokines in individuals with or without hookworm infections. We also estimated the absolute counts of CD4⁺ and CD8⁺ T cells as well as the frequencies of memory T cell and dendritic cell subsets. Finally, we also measured the levels of all of these parameters in a subset of individuals following treatment of hookworm infection.

Results

Our data suggest that hookworm infection is characterized by increased levels of markers associated with MT but not acute-phase proteins nor pro-inflammatory cytokines. Hookworm infections were also associated with increased levels of the anti – inflammatory cytokine – IL-10, which was positively correlated with levels of lipopolysaccharide (LPS). In addition, MT was associated with decreased numbers of CD8⁺ T cells and diminished frequencies of particular dendritic cell subsets. Antihelmintic treatment of hookworm infection resulted in reversal of some of the hematologic and microbiologic alterations.

Conclusions

Our data provide compelling evidence for MT in a human intestinal helminth infection and its association with perturbations in the T cell and antigen-presenting cell compartments of the immune system. Our data also reveal that at least one dominant counter-regulatory mechanism i.e. increased IL-10 production might potentially protect against systemic immune activation in hookworm infections.

Hookworm infections affect more than half a billion people worldwide and cause morbidity in the form of intestinal injury and blood loss. Host immunologic factors that influence the pathogenesis of disease in these individuals are not completely understood. Circulating microbial products such as LPS and markers associated with microbial translocation (transfer of microbes or microbial products from the intestine to the circulation) have been shown to play an important role in disease pathogenesis of certain infections like HIV. We have attempted to elucidate the role of the above mentioned factors in disease pathogenesis by comparing the plasma levels of the various markers in a group of hookworm infected and uninfected individuals. We show that circulating levels of microbial translocation markers are elevated in hookworm infected individuals, a potential cause of morbidity in these infections. This is associated with changes in the host immune system, especially in terms of lymphocyte and dendritic cells subsets. However, microbial translocation is not accompanied by increased levels of acute phase proteins or pro-inflammatory cytokines indicating that the parasite has evolved mechanisms to dampen LPS induced inflammation. Thus, our study highlights a novel pathway of pathogenesis in an intestinal helminth infection and improves our understanding of the various factors involved in the complex host-parasite interaction.

Effect of filarial infection on serum inflammatory and atherogenic biomarkers in coronary artery disease (CURES-121)

Helminth infections can potentially confer protection against metabolic disorders, possibly through immunomodulation. In this study, the baseline prevalence of lymphatic filariasis (LF) among subjects without (N = 236) and with (N = 217) coronary artery disease (CAD) was examined as part of the Chennai Urban Rural Epidemiological Study (CURES). The prevalence of LF was not significantly different between CAD(-) and CAD(+) subjects. The LF antigen load and antibody levels indicated comparable levels of infection and exposure between the groups. Within the CAD group, LF(+) and LF(-) subjects had no significant difference in the intimal medial thickness and high-sensitivity C-reactive protein values. However, LF infection was associated with augmented levels of tumor necrosis factor-α and interleukin-6 among CAD(+) subjects. The LF infection had no effect on serum adipocytokine profile. In conclusion, unlike type-2 diabetes, there is no association between the prevalence of LF and CAD and also no evidence of protective immunomodulation of LF infection on CAD in the Asian Indian population.

Circulating microbial products and acute phase proteins as markers of pathogenesis in lymphatic filarial disease

Lymphatic filariasis can be associated with development of serious pathology in the form of lymphedema, hydrocele, and elephantiasis in a subset of infected patients. Dysregulated host inflammatory responses leading to systemic immune activation are thought to play a central role in filarial disease pathogenesis. We measured the plasma levels of microbial translocation markers, acute phase proteins, and inflammatory cytokines in individuals with chronic filarial pathology with (CP Ag+) or without (CP Ag−) active infection; with clinically asymptomatic infections (INF); and in those without infection (endemic normal [EN]). Comparisons between the two actively infected groups (CP Ag+ compared to INF) and those without active infection (CP Ag− compared to EN) were used preliminarily to identify markers of pathogenesis. Thereafter, we tested for group effects among all the four groups using linear models on the log transformed responses of the markers. Our data suggest that circulating levels of microbial translocation products (lipopolysaccharide and LPS-binding protein), acute phase proteins (haptoglobin and serum amyloid protein-A), and inflammatory cytokines (IL-1β, IL-12, and TNF-α) are associated with pathogenesis of disease in lymphatic filarial infection and implicate an important role for circulating microbial products and acute phase proteins.

Lymphatic filariasis afflicts over 120 million people worldwide. While the infection is mostly clinically asymptomatic, approximately 40 million people suffer from overt, morbid clinical pathology, characterized by swelling of the scrotal area and lower limbs (hydrocele and lymphedema). Host immunologic factors that influence the pathogenesis of disease in these individuals are not completely understood. Circulating microbial products such as LPS and markers associated with microbial translocation have been shown to play an important role in disease pathogenesis of certain infections like HIV. Similarly, proteins associated with the acute phase response and related cytokines also play an important role in pathogenesis. We have attempted to elucidate the role of the above mentioned factors in disease pathogenesis by comparing the plasma levels of the various markers in four groups of individuals: chronic pathology individuals with or without active filarial infection, asymptomatic, filarial infected individuals and uninfected, endemic normal individuals. We show that circulating levels of LPS, acute phase proteins and certain cytokines are significantly elevated in filarial disease with active infection but not in the other groups indicating that filarial infection induced increased production of these factors correlated with the development of filarial lymphatic pathology.

Heightened measures of immune complex and complement function and immune complex-mediated granulocyte activation in human lymphatic filariasis

The presence of circulating immune complexes (CICs) is a characteristic feature of human lymphatic filariasis. However, the role of CICs in modulating granulocyte function and complement functional activity in filarial infection is unknown. The levels of CICs in association with complement activation in clinically asymptomatic, filarial-infected patients (INF); filarial-infected patients with overt lymphatic pathologic changes (CPDT); and uninfected controls (EN) were examined. Significantly increased levels of CICs and enhanced functional efficiency of the classical and mannose-binding lectin pathways of the complement system was observed in INF compared with CPDT and EN. Polyethylene glycol-precipitated CICs from INF and CPDT induced significantly increased granulocyte activation compared with those from EN, determined by the increased production of neutrophil granular proteins and a variety of pro-inflammatory cytokines. Thus, CIC-mediated enhanced granulocyte activation and modulation of complement function are important features of filarial infection and disease.

Attenuation of toll-like receptor expression and function in latent tuberculosis by coexistent filarial infection with restoration following antifilarial chemotherapy

Mycobacterium tuberculosis (Mtb) and filarial coinfection is highly prevalent, and the presence of filarial infections may regulate the Toll-like receptor (TLR)-dependent immune response needed to control Mtb infection. By analyzing the baseline and mycobacterial antigen–stimulated expression of TLR1, 2, 4, and 9 (in individuals with latent tuberculosis [TB] with or without filarial infection), we were able to demonstrate that filarial infection, coincident with Mtb, significantly diminishes both baseline and Mtb antigen-specific TLR2 and TLR9 expression. In addition, pro-inflammatory cytokine responses to TLR2 and 9 ligands are significantly diminished in filaria/TB-coinfected individuals. Definitive treatment of lymphatic filariasis significantly restores the pro-inflammatory cytokine responses in individuals with latent TB. Coincident filarial infection exerted a profound inhibitory effect on protective mycobacteria-specific TLR-mediated immune responses in latent tuberculosis and suggests a novel mechanism by which concomitant filarial infections predispose to the development of active tuberculosis in humans.

Lymphatic filariasis afflicts over 120 million people worldwide, while Mycobacterium tuberculosis infects over 2 billion people worldwide. Almost 90% of infected people harbor latent tuberculosis infection with no clinical manifestations. Toll-like receptors (TLRs), pattern-recognition receptors that are present on host immune cells, constitute an important facet of host immune response initiation against a variety of pathogens. Because lymphatic filariasis and tuberculosis are co-endemic in many parts of the world and because TLR modulation is an important feature of both infections, we examined the effect of coexisting filarial infection on TLR-specific immune responses in latent tuberculosis by comparing cellular immune responses to Toll ligands in individuals with latent tuberculosis with or without concomitant lymphatic filariasis. We first examined modulation of TLRs at the gene expression level and determined that downregulation of TLR2 and 9 is associated with coexisting filarial infection. We then determined that Toll ligand-induced pro-inflammatory cytokine production—which is crucial in host defense against TB—is diminished in the presence of filarial coinfection. Treatment of filarial infection restores cytokine production in individuals with latent TB. Thus, we conclude that coexisting filarial infections might significantly compromise essential immune responses in tuberculosis and that treatment of filarial infections would potentially confer tremendous benefit in combating tuberculosis.

Standardization of 192Ir solution at BARC

A radioactive solution of 192Ir was standardized at Bhabha Atomic Research Centre (BARC) under the international intercomparison programme of the Bureau International des Poids et Measures (BIPM) by 4pibeta-gamma coincidence and 4pigamma counting techniques, which are primary and secondary methods of standardization, respectively. The activity concentration of the 192Ir solution obtained by the efficiency extrapolation technique and as reported to BIPM was 203.15 kBq g(-1) with a combined uncertainty of +/-0.3%. The activity concentration determined by 4pigamma counting was 202.88 kBq g(-1) with a combined uncertainty of +/-1.3%. These measurement results are comparable within the uncertainty limits. Detailed uncertainty budget for both the primary and secondary methods are included.

Rubella serosurveys at three Aravind Eye Hospitals in Tamil Nadu, India

OBJECTIVE

To determine the susceptibility of female eye hospital staff to rubella infection and the potential risk for hospital-based rubella outbreaks.

METHODS

A prospective cohort study on the seroprevalence of rubella IgG antibodies was conducted at three large eye hospitals in Coimbatore, Madurai and Tirunelveli, Tamil Nadu, India, where young children with eye abnormalities attributable to congenital rubella are treated. A total of 1000 female hospital employees aged 18-40 years agreed to participate and gave written informed consent.

FINDINGS

The proportions of rubella-seronegative women were: 11.7% at Coimbatore, with a 95% confidence interval (CI) of 8.1-16.5; 15% at Madurai (95% CI = 12.3-18.1), and 20.8 at Tirunelveli (95% CI = 14.7-28.6). For the entire cohort the proportion seronegative was significantly higher among married women (21.5%) than among single women (14.0%) (P = 0.02). Rates of seronegativity were highest among physicians and lowest among housekeepers. All 150 seronegative women in the study sample accepted a dose of rubella vaccine.

CONCLUSION

These are the first rubella serosurveys to have been reported from eye hospitals in any country. The relatively high rate of susceptibility indicated a risk of a rubella outbreak, and this was reduced by vaccinating all seronegative women. A policy has been established at all three hospitals for the provision of rubella vaccine to new employees. Other hospitals, especially eye hospitals and hospitals in countries without routine rubella immunization, should consider the rubella susceptibility of staff and the risk of hospital-based rubella outbreaks.

National intercomparisons of 131I radioactivity measurements in nuclear medicine centres in India

National intercomparisons of activity measurements of 131I, a radioisotope widely used for diagnosis and therapy of thyroid related ailments, were initiated in 1979 as a quality assurance program, towards improving radiation safety procedures and related dosimetry in Nuclear Medicine Centres (NMCs) in India. Oral administration of a known quantity of radioiodine to patients requires accurate radioactivity measurements to be performed on a well-calibrated isotope calibrators. Under or over estimation of the activity due to a faulty or uncalibrated isotope calibrator could provide misleading results. Calibration of isotope calibrators and the traceablity of subsequent measurements to the national standards laboratory is one of the essential basic radiation safety requirement of the IAEA. In view of the stringent quality assurance requirements for activity measurements imposed by Atomic Energy Regulatory Board, a National Intercomparison Program was initiated and to date ten such intercomparison programs have been conducted by the Radiation Safety Systems Division, of the Bhabha Atomic Research Centre. This program has benefited the participants by making their measurements traceable to the National Primary Standards. Over the years there has been a marked increase in the number of NMCs participating in the intercomparison programs. As a result, the number of institution showing large deviation from the correct value has decreased considerably over the years. This program thus, has enabled participating NMCs to check their isotope calibrators so as to ensure proper delivery of radiation dose to the patients and hence to optimise patient exposure.