Pre-existing T Cell Memory to Novel Pathogens

Immunological experiences lead to the development of specific T and B cell memory, which readies the host for a later pathogen rechallenge. Currently, immunological memory is best understood as a linear process whereby memory responses are generated by and directed against the same pathogen. However, numerous studies have identified memory cells that target pathogens in unexposed individuals. How "pre-existing memory" forms and impacts the outcome of infection remains unclear. In this review, we discuss differences in the composition of baseline T cell repertoire in mice and humans, factors that influence pre-existing immune states, and recent literature on their functional significance. We summarize current knowledge on the roles of pre-existing T cells in homeostasis and perturbation and their impacts on health and disease.

SARS-CoV-2-specific T cells in unexposed adults display broad trafficking potential and cross-react with commensal antigens

The baseline composition of T cells directly affects later response to pathogens, but the complexity of precursor states remains poorly defined. Here, we examined the baseline state of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells in unexposed individuals. SARS-CoV-2-specific CD4+ T cells were identified in prepandemic blood samples by major histocompatibility complex (MHC) class II tetramer staining and enrichment. Our data revealed a substantial number of SARS-CoV-2-specific T cells that expressed memory phenotype markers. Integrated phenotypic analyses demonstrated diverse preexisting memory states that included cells with distinct polarization features and trafficking potential to barrier tissues. T cell clones generated from tetramer-labeled cells cross-reacted with antigens from commensal bacteria in the skin and gastrointestinal tract. Direct ex vivo tetramer staining for one spike-specific population showed a similar level of cross-reactivity to sequences from endemic coronavirus and commensal bacteria. These data highlight the complexity of precursor T cell repertoire and implicate noninfectious exposures to common microbes as a key factor that shapes human preexisting immunity to SARS-CoV-2.

Milk exosomes elicit a potent anti-viral activity against dengue virus

Background

Exosomes are nano-sized vesicles secreted by various cells into the intra and extracellular space and hence is an integral part of biological fluids including milk. In the last few decades, many research groups have proved the potential of milk exosomes as a sustainable, economical and non-immunogenic drug delivery and therapeutic agent against different pathological conditions. However, its anti-viral properties still remain to be unearthed.

Methods

Here, we have been able to isolate, purify and characterize the milk derived exosomes from Cow (CME) and Goat (GME) and further studied its antiviral properties against Dengue virus (DENV), Newcastle Disease Virus strain Komarov (NDV-K) and Human Immunodeficiency Virus (HIV-1) using an in-vitro infection system.

Results

TEM, NTA and DLS analysis validated the appropriate size of the isolated cow and goat milk exosomes (30–150 nm). Real-time PCR and immunoblotting results confirmed the presence of several milk exosomal miRNAs and protein markers. Our findings suggest that GME significantly decreased the infectivity of DENV. In addition, we confirmed that GME significantly reduces DENV replication and reduced the secretion of mature virions. Furthermore, heat inactivation of GME did not show any inhibition on DENV infection, replication, and secretion of mature virions. RNase treatment of GME abrogates the anti-viral properties indicating direct role of exosomes in DENV inhibition. In addition GME inhibited the infectivity of NDV-K, but not HIV-1, suggesting that the GME mediated antiviral activity might be virus specific.

Conclusion

This study demonstrates the anti-viral properties of milk exosomes and opens new avenues for the development of exosome-based therapies to treat viral diseases.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01496-5.

Immunogenic profiling of Mycobacterium tuberculosis DosR protein Rv0569 reveals its ability to switch on Th1 based immunity

Mycobacterium tuberculosis (M.tb) is a multifaceted bacterial pathogen known to infect more than 2 billion people globally. However, a majority of the individuals (>90%) show no overt clinical symptoms of active Tuberculosis (TB) and, it is reported that M.tb in these individuals resides in the latent form. Therefore, huge burden of latently infected population poses serious threat to human health. Inconsistent efficacy of BCG vaccine and poor understanding of latency-associated determinants contribute to the failure of combating M.tb. The discovery of DosR as the master regulator of dormancy, opened new avenues to understand the pathophysiology of the bacterium. Though the specific functions of various DosR genes are yet to be discovered, they have been reported as potent T-cell activators and could elicit strong protective immune responses. Rv0569 is a DosR-encoded conserved hypothetical protein overexpressed during dormancy. However, it is not clearly understood how this protein modulates the host immune response. In the present study, we have demonstrated that Rv0569 has a high antigenic index and induces enhanced secretion of Th1 cytokines IL-12p40 and TNF-α as compared to Th2 cytokine IL-10 in macrophages. Mechanistically, Rv0569 induced the transcription of these pro-inflammatory signatures through the activation of NF-κB pathway. Further, immunization of mice with DosR protein Rv0569 switched the immune response towards Th1-biased cytokine pattern, characterized by the enhanced production of IFN-γ, IL-12p40, and TNF-α. Rv0569 augmented the expansion of antigen-specific IFN-γ and IL-2 producing effector CD4⁺ and CD8⁺ T-cells which are hallmarks of Th1 biased protective immunity. Additionally, IgG2a/IgG1 and IgG2b/IgG1 ratio in the serum of immunized mice further confirmed the ability of Rv0569 to skew Th1 biased immune response. In conclusion, we emphasize that Rv0569 has the ability to generate signals to switch on Th1-dominated responses and further suggest that it could be a potential vaccine candidate against latent M.tb infection.

Tetravalent formulation of Polymeric nanoparticle-based vaccine induces a potent immune response against Dengue virus

Dengue is a mosquito-borne disease caused by the four serotypes of dengue virus (DENV 1-4). It is growing at an alarming rate globally, which could be partly attributed to the...

SARS-CoV-2-specific T cells in unexposed adults display broad trafficking potential and cross-react with commensal antigens

The baseline composition of T cells directly impacts later response to a pathogen, but the complexity of precursor states remains poorly defined. Here we examined the baseline state of SARS-CoV-2 specific T cells in unexposed individuals. SARS-CoV-2 specific CD4 + T cells were identified in pre-pandemic blood samples by class II peptide-MHC tetramer staining and enrichment. Our data revealed a substantial number of SARS-CoV-2 specific T cells that expressed memory phenotype markers, including memory cells with gut homing receptors. T cell clones generated from tetramer-labeled cells cross-reacted with bacterial peptides and responded to stool lysates in a MHC-dependent manner. Integrated phenotypic analyses revealed additional precursor diversity that included T cells with distinct polarized states and trafficking potential to other barrier tissues. Our findings illustrate a complex pre-existing memory pool poised for immunologic challenges and implicate non-infectious stimuli from commensal colonization as a factor that shapes pre-existing immunity.

ONE SENTENCE SUMMARY

Pre-existing immunity to SARS-CoV-2 contains a complex pool of precursor lymphocytes that include differentiated cells with broad tissue tropism and the potential to cross-react with commensal antigens.

Dengue Virus Induced COX-2 Signaling Is Regulated Through Nutrient Sensor GCN2

Nutrient sensor GCN2 plays a crucial role in the maintenance of cellular homeostasis during the condition of amino acid deprivation. Dysfunction in the GCN2 signaling underlies several chronic metabolic diseases. Recent studies highlight the anti-viral potential of GCN2 against RNA viruses such as Sindbis and HIV. However, its effect on dengue virus (DENV) pathogenesis remains poorly understood. Herein, we report that GCN2 deficient cells show increased DENV replication and viral yield in the culture supernatants compared to WT cells infected with DENV. Notably, enhanced DENV replication in GCN2^-/- cells is associated with increased COX-2/PGE₂ signaling. Conversely, GCN2 overexpression/activation effectively contains DENV infection by inhibiting COX-2/PGE₂ signaling. Mechanistically, deletion of GCN2 triggers enhanced production of COX-2/PGE₂ through profound activation of Iκκ-NF-κB signaling pathway. Altogether our results unveil a hitherto unrecognized role of GCN2 in DENV pathogenesis, thereby suggesting that targeting the GCN2 pathway might offer a novel therapeutic intervention against DENV infection.

Amino acid starvation enhances vaccine efficacy by augmenting neutralizing antibody production

Specific reduction in the intake of proteins or amino acids (AAs) offers enormous health benefits, including increased life span, protection against age-associated disorders, and improved metabolic fitness and immunity. Cells respond to conditions of AA starvation by activating the amino acid starvation response (AAR). Here, we showed that mimicking AAR with halofuginone (HF) enhanced the magnitude and affinity of neutralizing, antigen-specific antibody responses in mice immunized with dengue virus envelope domain III protein (DENVrEDIII), a potent vaccine candidate against DENV. HF enhanced the formation of germinal centers (GCs) and increased the production of the cytokine IL-10 in the secondary lymphoid organs of vaccinated mice. Furthermore, HF promoted the transcription of genes associated with memory B cell formation and maintenance and maturation of GCs in the draining lymph nodes of vaccinated mice. The increased abundance of IL-10 in HF-preconditioned mice correlated with enhanced GC responses and may promote the establishment of long-lived plasma cells that secrete antigen-specific, high-affinity antibodies. Thus, these data suggest that mimetics of AA starvation could provide an alternative strategy to augment the efficacy of vaccines against dengue and other infectious diseases.

Activation of integrated stress response pathway regulates IL-1β production through posttranscriptional and translational reprogramming in macrophages

Immune cells sense and programme its cellular machinery appropriately to the environmental changes through the activation of cytoprotective adaptive pathway so-called the "integrated stress response (ISR)". However, the mechanisms implicated in ISR-induced protective responses are poorly understood. Here, we show that ISR activation by arsenite (Ar) results in suppression of IL-1β production in macrophages and inhibition of DSS-induced colitis in a murine model through a novel posttranscriptional and translation regulatory (PTR) mechanism. Ar triggers PTR events through eIF2α-phosphorylation, which results in the attenuation of active polysome formation leading to the accumulation of translationally stalled IL-1β mRNAs. Translationally stalled IL-1β mRNAs recruit RNA-binding proteins (TIA-1/TIAR), resulting in the formation of RBP-RNA complexes known as stress granules (SGs). The SGs bound IL-1β mRNAs might undergo degradation through induction of autophagy. Also, we show that Ar posttranslationally impairs processing and secretion of IL-1β by diminishing inflammasome activation. Altogether, this study unveils a novel mechanism of IL-1β regulation and further suggests that pharmacological activation of cytoprotective ISR pathway might provide an effective therapeutic intervention against inflammatory diseases.

Amino acid starvation sensing dampens IL-1β production by activating riboclustering and autophagy

Activation of the amino acid starvation response (AAR) increases lifespan and acute stress resistance as well as regulates inflammation. However, the underlying mechanisms remain unclear. Here, we show that activation of AAR pharmacologically by Halofuginone (HF) significantly inhibits production of the proinflammatory cytokine interleukin 1β (IL-1β) and provides protection from intestinal inflammation in mice. HF inhibits IL-1β through general control nonderepressible 2 kinase (GCN2)–dependent activation of the cytoprotective integrated stress response (ISR) pathway, resulting in rerouting of IL-1β mRNA from translationally active polysomes to inactive ribocluster complexes—such as stress granules (SGs)—via recruitment of RNA-binding proteins (RBPs) T cell–restricted intracellular antigen-1(TIA-1)/TIA-1–related (TIAR), which are further cleared through induction of autophagy. GCN2 ablation resulted in reduced autophagy and SG formation, which is inversely correlated with IL-1β production. Furthermore, HF diminishes inflammasome activation through suppression of reactive oxygen species (ROS) production. Our study unveils a novel mechanism by which IL-1β is regulated by AAR and further suggests that administration of HF might offer an effective therapeutic intervention against inflammatory diseases.

Reduced intake of food (also known as dietary restriction) without malnutrition has been shown to benefit health in humans and animals, including an increase in life expectancy, metabolic fitness, and resistance to acute stress. Recent studies have attributed the benefits associated with dietary restriction to the reduced intake of amino acids. However, the underlying mechanisms through which amino acid restriction regulates various homeostatic processes are poorly defined. Here, we show that activation of amino acid starvation response (AAR) by the small molecule Halofuginone (HF) results in a significant inhibition of production of interleukin 1β (IL-1β), a proinflammatory mediator. We find that AAR provides protection from intestinal inflammation–associated pathology in a mouse model of colitis through a novel mechanism involving the formation of riboclusters (groups of RNA-binding proteins (RBPs) and stalled mRNA complexes) and autophagy. We further show that HF-mediated inhibition in IL-1β production is dependent on general control nonderepressible 2 kinase (GCN2), an amino acid deprivation sensor. This study provides the mechanisms regulating AAR-induced benefits in the context of inflammation and further suggests that the administration of HF might offer an effective therapeutic intervention against inflammatory diseases in mammals.

Mesoporous ZnO nanocapsules for the induction of enhanced antigen-specific immunological responses

The application of nanotechnology in vaccinology has fuelled rapid advancement towards the design and development of nanovaccines. Nanoparticles have been found to enhance vaccine efficacy through the spatiotemporal orchestration of antigen delivery to secondary lymphoid organs and antigen-presentation by Antigen Presenting Cells (APCs) synchronized with stimulation of innate and adaptive immune responses. Metal based nanoparticles (MNPs) have been extensively engineered for the generation of nanovaccines owing to their intrinsic adjuvant-like properties and immunomodulatory functions. Furthermore, mesoporous nanocapsules of late have attracted researchers due to their precise size and exclusive capacity to encapsulate a wide range of biomolecules and their sustained release at the targeted sites. Herein, we have designed a novel mesoporous ZnO nanocapsule (mZnO) having a size of ∼12 nm with an average pore diameter of 2.5 nm, using a surfactant-free sonochemical method and investigated its immunomodulatory properties by using Ova loaded mZnO nanocapsules [mZnO(Ova)] in a mice model. Our findings show that mZnO(Ova) administration steered the enhanced expansion of antigen-specific T-cells and induction of IFN-γ producing effector CD4⁺ and CD8⁺ T-cells. Also, antigen-specific IgG levels were enriched in both the serum and lymph nodes of mZnO(Ova) immunized mice. Further, we noticed a substantial increase in serum IgG2a or IgG2b levels and IFN-γ secretion in Ova restimulated splenocytes from mZnO(Ova) immunized mice, indicating that mZnO(Ova) skew Th1 type immune response. Overall, the uniqueness of mZnO nanocapsules in terms of the defined particle to pore numbers ratio (maximum of three cavities per particle) allows loading antigens efficiently. Given these features in combination with its immunomodulatory characteristics reinforces the idea that mZnO could be used as an effective antigen-adjuvant platform for the development of novel nano-based vaccines against multiple diseases.

Detection of Plasmid Mediated AmpC-β lactamases Among Gram-Negative Uropathogens at a Tertiary Care Hospital, Dhaka City

Plasmid-mediated AmpC β-lactamase (PMABL) resistance among gram negative bacilli is an emerging problem worldwide. They likely originate from chromosomal AmpC of certain Gram-negative bacterial species and subsequently are mobilized to transmissible plasmids. There are reports of unfavorable clinical outcomes in patients infected with these organisms and treated with broad-spectrumcephalosporins. The present cross sectional study was designed to detect PMABL genes among gram negative uropathogens in a tertiary care hospital, Dhaka city, Bangladesh from January 2014 to December 2014. Total 138 gram negative uropathogens were identified by the conventional methods and were screened for AmpC production using cefoxitin discs. Confirmatory phenotypic identification was done by modified three dimensional test (MTDT). The common AmpC genotypes ACC, FOX, MOX, DHA, CIT and EBC types were determined by a multiplex PCR.PMABL genes were detected by PCR in 90% of cefoxitin resistant isolates and the molecular types of the genes detected predominantly were CIT, DHA followed by EBC and ACC types. Overall, PMABL genes were detected in 32.61% (45/138) of the studied gram negative uropathogens which is alarming. All (100%) the plasmid mediated AmpC β-lactamase producers showed resistance to amoxicillin-clavulanic acid, ceftazidime, ceftriaxone, cefotaxime and cefoxitin. These results emphasize that clinical laboratories should consider the tests for the detection of PMABL genes for infection control and formulation of effective antibiotic policy.

Addison's Disease: A Diagnostic Dilemma

Adrenal insufficiency is a rare disease, but is life threatening when overlooked. Addison's disease may be an acquired form of adrenal insufficiency due to the destruction or dysfunction of the adrenal cortex. It affects both glucocorticoid and mineralocorticoid function. Main presenting symptoms of Addison's disease such as fatigue, anorexia, vomiting and convulsion often mimics central nervous system (CNS) infections. We describe a case of Addison's disease who was initially misdiagnosed as a case of meningo-encephalitis subsequently renal tubular acidosis and finally Addison's disease. Addison's disease can remain unrecognized until acute crisis and sometimes it may be misdiagnosed.

Role of pRIFLE Criteria in Early Diagnosis of Severity Staging of Neonatal AKI and its Impact on Management

Mortality is high among sick neonates who have concomitant acute kidney injury (AKI). This observational study was done at Special Care Baby Unit (SCABU) of Dhaka Medical College Hospital (DMCH), Bangladesh from October 2013 to March 2014 to find out the role of pRIFLE criteria in prediction of severity stages of AKI in neonate and early intervention to see the immediate outcome. A total of 44 neonates with AKI were included, all were treated conservatively and with intermittent peritoneal dialysis (IPD) as needed. The neonate of ≤7 days old comprised the main bulk (n=28) and M: F = 21: 23. The diagnosis was based on eCCL criteria of pRIFLE showed that 40.9% neonates were at risk of AKI, 20.5% have had already injured. Higher proportions of neonates were classified as failure (38.6%). The distribution of biochemical parameters among three stages of AKI showed serum potassium was significantly higher in failure group (p<0.001). The serum creatinine both at baseline and at next evaluations were significantly raised in the failure group (p<0.001). However, failure group had a significantly longer hospital stay compared to risk and injury group (p<0.001). Multiorgan failure was found to be lower in the risk group compared to other two groups (p=0.026). Majority of the failure group needed dialysis as compared to the risk and injury group (p<0.001). The mortality was progressively higher from risk to failure groups (p=0.106). Overall 27% of the neonates diagnosed AKI by pRIFLE were died of the disease. The study concluded that pRIFLE staging in AKI is useful and sensitive in the diagnosis and management of AKI in neonates.

A Comprehensive Gene Expression Meta-analysis Identifies Novel Immune Signatures in Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA), a symmetric polyarticular arthritis, has long been feared as one of the most disabling forms of arthritis. Identification of gene signatures associated with RA onset and progression would lead toward development of novel diagnostics and therapeutic interventions. This study was undertaken to identify unique gene signatures of RA patients through large-scale meta-profiling of a diverse collection of gene expression data sets. We carried out a meta-analysis of 8 publicly available RA patients’ (107 RA patients and 76 healthy controls) gene expression data sets and further validated a few meta-signatures in RA patients through quantitative real-time PCR (RT-qPCR). We identified a robust meta-profile comprising 33 differentially expressed genes, which were consistently and significantly expressed across all the data sets. Our meta-analysis unearthed upregulation of a few novel gene signatures including PLCG2, HLA-DOB, HLA-F, EIF4E2, and CYFIP2, which were validated in peripheral blood mononuclear cell samples of RA patients. Further, functional and pathway enrichment analysis reveals perturbation of several meta-genes involved in signaling pathways pertaining to inflammation, antigen presentation, hypoxia, and apoptosis during RA. Additionally, PLCG2 (phospholipase Cγ2) popped out as a novel meta-gene involved in most of the pathways relevant to RA including inflammasome activation, platelet aggregation, and activation, thereby suggesting PLCG2 as a potential therapeutic target for controlling excessive inflammation during RA. In conclusion, these findings highlight the utility of meta-analysis approach in identifying novel gene signatures that might provide mechanistic insights into disease onset, progression and possibly lead toward the development of better diagnostic and therapeutic interventions against RA.

Health Related Quality of Life in Children with Nephrotic Syndrome in Bangladesh

Outcome of children with nephrotic syndrome has continued to improve over time. However minimal data exist to describe health-related quality of life in children with nephrotic syndrome. This cross sectional study was conducted over a period of six months to assess the health related quality of life in children with nephrotic syndrome in the Department of Pediatric Nephrology, Dhaka Medical College Hospital, Bangladesh. Fifty children (age ranged 2-12 years) with nephrotic syndrome who had three or more relapses diagnosed at least one year back receiving treatment and on follow up were included in this study. Quality of Life scores were collected using Bengali translated instruments- the Pediatric Quality of Life Inventory™ (PedsQL™) version 4.0 Generic Scale and the Pediatric Quality of Life Questionnaire for Nephrotic Syndrome proxy-report from parents. Medical data and Demographic data were collected from medical records, and from parents in outpatient department or hospital ward. Interviews of eligible guardians were performed individually to collect quality of life (QoL) scores. Among 50 children, mean±SD age of the children was 7±2.92 years. Most children were male (58%). Female parents respondent during interview were 62%, most parents (48%) were very poor in socioeconomic condition. Most children had frequent relapses (60%). Median time since diagnosis was 2 years. Regarding PedsQL scores, child age with physical summary score (p value <0.001), child age with social summary score (p value 0.003), frequent relapse with kidney disease summary score (p value 0.04) and time since diagnosis (p value <0.001) were statistically significant. In conclusion physical and social summary score were worst. Frequent relapse found to be an important factor in impaired QoL. Prolonged duration of the disease activity was associated with significant impairment of QoL.

Experience of Percutaneous Versus Surgically Placed Catheter for Continuous Ambulatory Peritoneal Dialysis in Children with Chronic Kidney Disease Stage-V

The lifespan and outcome of end stage renal disease (ESRD) children have dramatically improved since the development of continuous ambulatory peritoneal dialysis (CAPD), it offers several advantages over hemodialysis. Percutaneous placement of CAPD catheters in children is minimally invasive, reliable, safe and cost-effective method. Percutaneous method of CAPD catheter insertion can be used in children to avoid the complications of general anesthesia and surgery. This study was done to evaluate the efficacy of CAPD in children, to find out the complication profile of CAPD & to compare the advantages of surgical versus percutaneously placed CAPD catheters in children. This prospective longitudinal comparative study was carried out in the department of Pediatric Nephrology, Dhaka Medical College Hospital (DMCH), Bangladesh from July 2011 to June 2014. A total of 8 children with ESRD were included (Age 5-14 year, M: F=1: 1). All underwent CAPD, Group I = surgically placed CAPD catheter (N=5), Group II = percutaneously placed CAPD catheter (N=3). Average duration of CAPD in Group I and Group II were 31.6 vs. 9 (months) with a total of 158 vs. 27 patient months of CAPD respectively. The rate of complications of the 2 groups and their outcome were compared. Common complications being observed were peritonitis 1 episode per 12.1 vs. 1.8 patient months (p<0.001), catheter obstruction by omental capture 1 vs. 3 in Group I and Group II respectively. Catheter tip dislocation was commonly found in all Group II children (p<0.01) and all needed laparotomy and omentectomy. Three out of 5 in Group I is still on CAPD, 1 transferred to HD and another 1 expired due to uncontrolled hypertension with congestive heart failure. Among 3 of Group II, 2 died of repeated peritonitis and hypertensive complications and rest 1 is transferred to HD after 1year due to exit site fluid leaking. Satisfactory level of improvement of mean weight, mean serum albumin and declining of serum creatinine in both groups has been found after CAPD. Although CAPD is an effective modality of renal replacement therapy for children, but percutaneous method of catheter insertion is associated with higher rate of complications. Placement of catheter by surgical method with elective omentectomy will reduce catheter related complications. Early detection of peritonitis and prompt therapy is essential for a favourable outcome.

Transcriptome meta-analysis reveals a dysregulation in extra cellular matrix and cell junction associated gene signatures during Dengue virus infection

Dengue Viruses (DENVs) cause one of the most prevalent arthropod-borne viral diseases affecting millions of people worldwide. Identification of genes involved in DENV pathogenesis would help in deciphering molecular mechanisms responsible for the disease progression. Here, we carried out a meta-analysis of publicly available gene expression data of dengue patients and further validated the meta-profile using in-vitro infection in THP-1 cells. Our findings reveal that DENV infection modulates expression of several genes and signalling pathways including interferons, detoxification of ROS and viral assembly. Interestingly, we have identified novel gene signatures comprising of INADL/PATJ and CRTAP (Cartilage Associated Protein), which were significantly down-regulated across all patient data sets as well as in DENV infected THP-1 cells. PATJ and CRTAP genes are involved in maintaining cell junction integrity and collagen assembly (extracellular matrix component) respectively, which together play a crucial role in cell-cell adhesion. Our results categorically reveal that overexpression of CRTAP and PATJ genes restrict DENV infection, thereby suggesting a critical role of these genes in DENV pathogenesis. Conclusively, these findings emphasize the utility of meta-analysis approach in identifying novel gene signatures that might provide mechanistic insights into disease pathogenesis and possibly lead towards the development of better therapeutic interventions.

Risk factors of multi-drug-resistant tuberculosis in Bangladeshi population: a case control study

Despite success in tuberculosis control, multi-drug resistant tuberculosis in Bangladesh is increasing and currently multi-drug-resistant tuberculosis rate is 3.6% in new cases and 19% in re-treatment cases. This study focused on determination of multi-drug-resistant tuberculosis which is warranted for effective prevention strategy. An unmatched case control study was conducted in 2010. Purposively recruited 136 culture-proved multi-drug-resistant- tuberculosis cases and 152 cured tuberculosis patients were interviewed. Associations between exposure and outcome variables were initially tested by chi2-test, t-test. A result was considered significant at p value < 0.05. Effects of exposure variables were also assessed after adjusting for other variables by binary logistic regression models. Crude and adjusted Odds Ratio with 95% Confidence Interval was computed. Younger age (p = 0.008) and, peri-urban locality (p = 0.002) were associated with multi-drug-resistant tuberculosis. History of contact (p < 0.001) and tuberculosis in the past (p < 0.001) were four and eight times, respectively, more likely to influence multi-drug-resistant tuberculosis. Regularity [Odds Ratio 0.05; 95% Confidence Interval (0.01 to 0.39)] and always observation of treatment [Odds Ratio 0.25; 95% Confidence Interval (0.10 to 0.61)], sputum conversion [Odds Ratio 0.02; 95% Confidence Interval (0.01 to 0.08)] negatively associated with multi-drug-resistant tuberculosis. Gender and socio-economic status did not show any influence. Treatment course and sputum conversion was the best predictors. Like other developing countries adequacy of treatment is the most important exposure variable. Strengthening of control activities might contribute in preventing development of resistance in tuberculosis patients.

Low serum immunglobulin G (IgG) during nephrosis is a predictor of urinary tract infection (UTI) in children with nephrotic syndrome

Low serum level of IgG, complement C3 and C4 in nephrotic syndrome children may cause increased susceptibility to infection. Serum level of IgG and complements in nephrotic children (NS) with UTI has been analyzed in this cross sectional study. It was carried out in the department of Pediatric nephrology, National Institute of Kidney Diseases & Urology (NIKDU), Dhaka, Bangladesh. The study subjects were followed up prospectively for one year to see and compare the frequency of relapse of NS and UTI. Patients were selected in a nonrandom purposive technique. Nephrotic syndrome children with initial attack between 1-12 year of age were included over a period of one year. The patients were grouped into Group I - UTI positive and Group II - UTI negative depending on urine culture positivity and colony count >10⁵ CFU/ml. Serum IgG and complements C3, C4 levels were done in both groups during nephrosis and were compared. A total of 101 children M: F 1.7:1, mean age 5.96±3.2 years were included in this study. Group I, n=45 vs. Group II, n=56. The mean serum level of IgG was low in Group I (549.91±210.71 vs. 728.64±235.81mg/dl, p<0.001). Serum IgG level less than 700mg/dl was found in 37 vs. 23 children {x² (¹) 17.52 p<0.001, OR=6.63}. Mean serum complement C3 level was also low in Group I (123.09±40.52 vs. 143.38±37.06mg/dl, p<0.05). But complement C3 and C4 level do not carry any risk of developing UTI in nephrotic children. Higher number of children in Group II were at remission (n=24) during follow up, while frequent relapsers were high in Group I (n=22). Increased frequency of UTI attack (88 episodes) was found in Group I children compared to none in Group II during follow up. So low serum level of IgG in children with NS during nephrosis can predict UTI with an odds ratio of 6.63 as well as relapse. Serum level of C3, C4 do not associated with any risk of development of UTI in NS children.

Thyroid function in children with nephrotic syndrome

This study was done to find out the thyroid function of nephrotic children during nephrosis and to compare any significant changes of thyroid function status during nephrosis and remission. This is an observational study with prospective follow up of study subjects. It was carried out over a period of one year from July'2006 to June'2007 in the department of Paediatric Nephrology, National Institute of Kidney Diseases & Urology (NIKDU), Dhaka, Bangladesh. A total of 85 nephrotic children with initial attack and relapse cases were studied. Age ranged from 2-12 years, M: F=1.7:1. All patients were clinically euthyroid. The mean value of serum T3 (0.65±0.31 ng/ml) and T4 (5.04±4.18 μg/ml) in 85 nephrotic children during nephrosis were within normal limit. But the mean value of thyroid stimulating hormone (TSH) was higher than normal level (7.1±5.8 MIU). In 21 nephrotic children thyroid function status was compared during nephrosis and 4 weeks later after achieving remission. A significant increase in TSH level during nephrosis (9.11±6.36 vs. 4.2±3.6 MIU/L, p = 0.005) was found, which normalized during remission. No significant difference between T3 and T4 level was observed. There was a negative correlation of serum albumin with serum TSH level (r = -0.216, p = 0.047). This result suggests that children with nephrotic syndrome commonly have a state of mild or subclinical hypothyroidism during proteinuria although they are clinically euthyroid. This temporary hypothyroid state improves with remission and needs no treatment.

Qualitative and quantitative analysis of goat ovaries, follicles and oocytes in view of in vitro production of embryos

Goat ovaries were collected from the slaughterhouse and categorized as right, left, corpus luteum (CL)-present and -absent group and evaluated on the basis of weight (g), length (cm), width (cm), number of follicles, follicles aspirated and number and state of cumulus-oocyte-complexes (COCs). Comparatively higher weight [(0.66+/-0.02) vs (0.64+/-0.02) g], length [(1.17+/-0.02) vs (1.11+/-0.02) cm] and width [(0.77+/-0.02) vs (0.74+/-0.02) cm] were found in right ovaries than those of left. On the other hand significantly (P<0.05) higher weight [(0.71+/-0.03) vs (0.64+/-0.01) g] and width [(0.76+/-0.03) vs (0.75+/-0.01) cm] were found in CL-present group than those of CL-absent group of ovaries. The left ovaries contained comparatively higher number of normal COCs [(1.06+/-0.09) per ovary] than right ovaries [(1.03+/-0.10) per ovary] and the similar trend was found in total number of follicles [(4.51+/-0.25) vs (4.30+/-0.23) per ovary] and follicles aspirated [(2.55+/-0.14) vs (2.52+/-0.12) per ovary]. But the total COCs per ovary was almost similar in both ovaries [right and left: (1.85+/-0.12) and (1.85+/-0.11) per ovary, respectively]. Higher number of total COCs [(1.87+/-0.09) vs (1.76+/-0.16) per ovary], total number of follicles [(4.45+/-0.19) vs (4.16+/-0.37) per ovary], follicles aspirated [(2.55+/-0.10) vs (2.48+/-0.21) per ovary] and normal COCs [(1.12+/-0.07) vs (0.76+/-0.14) per ovary] were found in CL-absent group than those of CL-present group of ovaries.

Antidiarrhoeal activity of the ethanol extract of Paederia foetida Linn. (Rubiaceae)

Paederia foetida L. is used as a remedy for diarrhoea and dysentery in Asia, but has not been investigated for its antidiarrhoeal properties. Antidiarrhoeal activity of 90% ethanol extract of Paederia foetida was investigated in this study using castor oil and magnesium sulphate-induced diarrhoea models in mice. The extract significantly increased the latent period of diarrhoea in both the models. In the castor oil study, the purging index (PI) value lowered in 1 h of the study at (100, 250 and 500 mg/kg) doses. The effect continued up to 6-h period only at 500 mg/kg dose. The plant notably reduced the purging index value in a dose-dependent manner in magnesium sulphate-induced diarrhoea. Paederia foetida, in general, reduced the gastrointestinal motility with barium sulphate milk both in 15- and 30-min time intervals. The extract significantly decreased the cisplatin-induced gastrointestinal motility at all doses at both time intervals. The extract also enhanced the morphine-induced reduction of motility at 500 mg/kg dose level at both time intervals. The results suggest that Paederia foetida showed antidiarrhoeal activity by inhibiting intestinal motility and justify its use in traditional medicine.

Platelet Activating Factor antagonists

Platelet Activating Factor (PAF) is a D-glycerol derived phosopholipid which is a potent endogenous mediator of inflammation. PAF is synthesized and released by a variety of cell types and elicits its biological activity by interacting with specific G-protein coupled receptors found on platelets, neutrophils, and other inflammatory cells. The physiological consequences of the interaction on PAF with its receptor include an increase in vascular permeability, hypotension, bronchoconstriction, and platelet and neutrophil aggregation. These biological effects are consistent with the concept that PAF is involved in a number of inflammatory diseases such as septic shock and asthma (Arimura A., 1998). Given the potent pathophysiological effects of PAF, a great deal of effort has been focused on the discovery of agents which block the action of PAF at its receptor. Within the past 10 years, a wide range of structures have been identified as PAF antagonists. These include not only PAF analogs, but also antagonists derived form natural product as well as non-lipid synthetic compounds. Several theories have been proposed to unify these diverse structural classes, but sophisticated molecular models of the receptor have not been widely employed (Braquet P., 1987). The discovery of new PAF antagonists has relied heavily on traditional medicinal chemistry approaches. A number of PAF antagonists have advanced to clinical evaluation. While several early compounds demonstrated efficacy in animal models of asthma they have failed to provide benefit for this condition in man. The current generation of potent antagonists are being evaluated as therapies for sepsis, pancreatitis and other disorders (Braquet C., 1991).

Effects of diazepam and cinchocaine on biogenic amines

Neurochemical and behavioural research show that benzodiazepines are well know anxiolytic drugs, which are also used for the treatment of epilepsy, hypnosis and insomnia. Administration of benzodiazepine to experimental animals produces anxiolytic-like effects in various animal and decreases exploratory activity. Psychomotor stimulants such as cinchocaine also showed potent effect on brain biogenic amines and their metabolite. The present studies indicate the changes in dopamine and 5-HT and their metabolites levels after acute administration of cinchocaine and diazepam.

Role of radioiodine in management of thyroid cancer: experience with 70 cases

Results of 70 cases of differentiated thyroid carcinoma managed with I131 and surgery have been reported. These results add to the body of knowledge that already exists in the field of treatment of thyroid cancer with radioactive iodine. These results also indicate that the success of radioiodine therapy depends on adequate surgical removal of the thyroid tissue.