The sociopolitical in human genetics education

Education must go beyond only countering essentialist and deterministic views of genetics.

Diversity and functional characterization of endophytic Methylobacterium isolated from banana cultivars of South India and its impact on early growth of tissue culture banana plantlets

AIMS

This study aimed at determining the distribution, colonization and growth promoting nature of Methylobacterium spp. in tissue culture banana plantlets.

METHODS AND RESULTS

Leaf samples from different field grown banana cultivars were used for Methylobacterium spp., isolation. Metabolic profile and functional characterization for plant growth-promoting traits of the isolates were assessed. The isolates were confirmed using 16S rRNA gene sequencing analysis, which resulted in six distinct species of Methylobacterium namely M. radiotolerans, M. salsuginis, M. thiocyanatum, M. rhodesianum, M. rhodinum and M. populi. Methylobacterium spp. inoculation experiment was conducted under hydroponic system in tissue culture banana plantlets (germ free) with eight selected isolates. A significant increase in growth parameters of Methylobacterium treated plantlets compared to uninoculated control was observed. Methylobacterium salsuginis TNMB03-gfp29 was developed and colonization micrograph was obtained using confocal laser scanning microscopy (CLSM) and scanning electron microscopy in different parts of banana plantlets (root, stem and leaves).

CONCLUSION

Field grown banana plants found to harbour diverse endophytic Methylobacterium population. Our finding suggests that endophytic Methylobacterium species may provide significant plant growth promoting compounds/nutrients to the banana plants. The experimental results demonstrated the efficacy of Methylobacterium spp. as a potential bioinoculant and can be exploited as a phyllosphere and rhizosphere based bioinoculant for the initial establishment and growth of tissue culture banana plantlets.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study extended our knowledge on the distribution of Methylobacterium spp. in banana plants and endophytic colonization nature of this particular genus in plants. In addition, efficient isolate (M. salsuginis TNMB03) identified in this study may be promoted as bio-inoculants for banana plants after field evaluation.

HLA genetics in bipolar disorder

OBJECTIVE

Bipolar Disorder (BD) is characterized by deregulated adaptive immune processes. Recent genome-wide association studies (GWAS) implicate the major histocompatibility complex (MHC) region in BD. The present study investigates the potential influence of variations in human leukocyte antigen (HLA) on BD risk and/or clinical presentations. This may have relevance to the dysregulated inflammatory processes commonly found in BD.

METHOD

DNAs from 475 BD patients and 195 healthy controls (HC) were genotyped for classical HLA class I and II loci.

RESULTS

We found that: (i) the HLA-A*02~B*44~DRB1*07 sub-haplotype is less prevalent in BD, vs. HC (pc = 2.4 × 10^-2 ); (ii) the 57.1 and the 8.1-derived ancestral haplotypes i.e. HLA-A*02~B*57~Cw*06~DRB1*07~DQB1*09 and HLA-A*02~B*08~Cw*07 are associated with rapid cycling (pc = 1.9 × 10^-3 and 1.05 × 10^-2 , respectively); (iii) the 8.1AH-derived HLA class II-DRB*03~HLA-DQB1*02 sub-haplotype is more frequent in BD patients with a history of suicidal behaviors (pc = 2.1 × 10^-2 ); and (iv) disease onset by an hypomanic episode or by psychotic symptoms are, respectively, more frequent in BD patients bearing the 7.1 AH-derived A*03~B*07~DRB1*15 sub-haplotype (pc = 8.5 × 10^-3 ) and the HLA-A*02~B*07~DRB1*15 sub-haplotype (pc = 4.0 × 10^-2 ).

CONCLUSION

Corroborating the established link between these HLA haplotypes/sub haplotypes and common immune disorders, our findings suggest possible HLA-mediated proinflammatory processes operating in BD.

Diversity of culturable methylotrophic bacteria in different genotypes of groundnut and their potential for plant growth promotion

This study aimed at documenting the culturable methylotrophic bacterial diversity across different groundnut genotypes and evaluating their effect on the growth of groundnut. 80 methylotrophic bacterial isolates were obtained from the phyllosphere of 15 groundnut genotypes collected from Tamil Nadu, India. The bacterial isolates were identified through sequencing of the 16S rDNA and were tested for their plant growth-promoting properties. Groundnut seeds were inoculated with methylotrophic bacteria and their effect on growth was evaluated via in vitro and pot experiments. Molecular identification revealed that the isolates belonged to 30 different species. A higher diversity of methylotrophic bacteria at genus and species level was found in groundnut genotype TMV2. Shannon diversity index was the highest in genotype TMV7, followed by VRI2 and TMV2. Similarly, geographical location also influenced the diversity of methylotrophic bacteria. In vitro seed germination assay revealed that methylotrophic isolates enhanced root growth and improved formation of root hair. The radicle length of treated seeds ranged from 2.7 to 8.4 cm. A higher shoot length was observed in the plants from seeds treated with Methylobacterium radiotolerans VRI8-A4 (27.3 cm), followed by Pseudomonas psychrotolerans TMV13-A1 (26.3 cm) and Bacillus aryabhattai K-CO3-3 (23 cm). The findings of this study strongly suggest that beneficial methylotrophic bacteria associated with the phyllosphere of groundnut play a major role in regulating plant growth.

Multicomponent Domino Synthesis, Anticancer Activity and Molecular Modeling Simulation of Complex Dispirooxindolopyrrolidines

A series of spirooxindolopyrrolidine fused N-styrylpiperidone heterocyclic hybrids has been synthesized in excellent yield via a domino multicomponent protocol that involves one-pot three component 1,3-dipolar cycloaddition and concomitant enamine reactions performed in an inexpensive ionic liquid, namely 1-butyl-3-methylimidazolium bromide ([bmim]Br). Compounds thus synthesized were evaluated for their cytotoxicity against U-937 tumor cells. Interestingly; compounds 5i and 5m exhibited a better cytotoxicity than the anticancer drug bleomycin. In addition; the effect of the synthesized compounds on the nuclear morphology of U937 FaDu cells revealed that treatment with compounds 5a–m led to their apoptotic cell death.

Transfusion support in preterm neonates <1500 g and/or <32 weeks in a tertiary care center: A descriptive study

BACKGROUND:

Lack of recent studies focusing on indications, pattern, and benefits of transfusions in low birth weight (B.Wt) and low gestational age (GA) preterm neonates prompted us to undertake this study.

AIM:

To estimate the transfusion requirements and outcomes in preterm neonates <1500 g and/or <32 weeks.

SETTINGS AND DESIGN:

This is a cross-sectional study conducted over a period of 2 years in a tertiary care center.

MATERIALS AND METHODS:

This study was conducted with 101 preterm neonates <1500 g and/or <32 weeks who received blood transfusions in the Neonatal Intensive Care Unit. Restrictive pattern of transfusion was followed. Demographic details and antenatal, neonatal, laboratory, and transfusion parameters were collected.

STATISTICAL ANALYSIS USED:

Statistical analyses were performed using SPSS 16.

RESULTS:

The study participants received 311 transfusions. Transfusion requirements decreased with increasing GA and B.Wt. Majority of blood transfusions occurred during the first 2 weeks of life. Packed red blood cells (PRBCs) were the most frequent blood components transfused. Ninety-six percent of the study population had an uneventful transfusion. Mean hemoglobin improvement after PRBC transfusions was 2.3 ± 2.1 g/dl. Improvement in apnea occurred in 76% PRBC transfusions. Infants with sepsis, patent ductus arteriosus, bronchopulmonary dysplasia, disseminated intravascular coagulation, and dyselectrolytemia received more number of transfusions.

CONCLUSION:

This study would serve as an audit for neonatal blood transfusion therapy. Close adherence to neonatal transfusion policy and restrictive transfusion guidelines helps reduce inappropriate use of blood products and adverse transfusion reactions.

Association of NKG2D gene variants with susceptibility and severity of rheumatoid arthritis

NKG2D (KLRK1) is a C-type lectin receptor present on natural killer (NK) cells, γδ, CD8⁺ and CD4⁺ T cells. Upon ligand binding, NKG2D mediates activatory and co-stimulatory signals to NK cells and activated CD4⁺ T cells, respectively. Polymorphisms in NKG2D predispose to infectious diseases, cancer, transplantation and autoimmune disorders. We studied the influence of this NK receptor polymorphism on predisposition to and modification of the disease phenotype in patients with rheumatoid arthritis (RA). Eight different single nucleotide polymorphisms (SNP) in the NKG2 gene were genotyped in 236 patients with RA and 187 controls using Taqman 5' nuclease assays. NKG2D genotype/allele frequency did not differ between patients and controls. Subgroup analysis showed that the frequency of A allele of NKG2D9 and T allele of NKG2D10 was significantly higher in patients with deformities (a marker of severe disease) [11 versus 5%, Pc = 0·03, odds ratio (OR) = 2·44, 95% confidence interval (CI) = 1·09-5·98 and 10 versus 4%, Pc = 0·04, OR = 2·45, 95% CI = 1·05-6·39, respectively], while the frequency of alleles G of NKG2D9 and A of NKG2D10 was greater in patients without deformities (Pc = 0·03, OR = 0·41, 95% CI = 0·17-0·91 and Pc = 0·04, OR = 0·41, 95% CI = 0·16-0·96). Similar trends of association were observed with deforming phenotype of RA in female patients and deforming young onset RA subgroups. Haplotype analysis revealed that the frequency of haplotype G-C-A-G-A-T-C-C was higher in patients than in controls (12 versus 8%, P = 0·04, OR = 1·61, 95% CI = 1·01-2·55), suggesting that it may predispose to RA. Our study suggests that the NKG2D gene polymorphisms may modify the risk of development and severity of RA.

Emergence of dengue in the tribal pockets of Nilgiris district, Tamil Nadu

As original tribal ways of living have morphed from a forest dweller existence, dengue is no longer an urban infection but is now also found in rural hilly areas. The spread of dengue is enhanced by the frequent movement of people to endemic areas where there is a vector mosquito presence. The impact of the virus is known to be great in the immunologically naive population. Our study reports on the threat of the dengue virus in these hilly areas.

Violent suicidal behaviour in bipolar disorder is associated with nitric oxide synthase 3 gene polymorphism

OBJECTIVE

Given the importance of nitric oxide system in oxidative stress, inflammation, neurotransmission and cerebrovascular tone regulation, we postulated its potential dysfunction in bipolar disorder (BD) and suicide. By simultaneously analysing variants of three isoforms of nitric oxide synthase (NOS) genes, we explored interindividual genetic liability to suicidal behaviour in BD.

METHOD

A total of 536 patients with BD (DSM-IV) and 160 healthy controls were genotyped for functionally relevant NOS1, NOS2 and NOS3 polymorphisms. History of suicidal behaviour and violent suicide attempt was documented for 511 patients with BD. Chi-squared test was used to perform genetic association analyses and logistic regression to test for gene-gene interactions.

RESULTS

NOS3 rs1799983 T homozygous state was associated with violent suicide attempts (26.4% vs. 10.8%, in patients and controls, P = 0.002, corrected P (Pc) = 0.004, OR: 2.96, 95% CI = 1.33-6.34), and this association was restricted to the early-onset BD subgroup (37.9% vs. 10.8%, in early-onset BD and controls, P = 0.0003, Pc = 0.0006 OR: 5.05, 95% CI: 1.95-12.45), while we found no association with BD per se and no gene-gene interactions.

CONCLUSION

Our results bring further evidence for the potential involvement of endothelial NOS gene variants in susceptibility to suicidal behaviour. Future exploration of this pathway on larger cohort of suicidal behaviour is warranted.

Human leukocyte antigen-G polymorphism influences the age of onset and autoantibody status in rheumatoid arthritis

The study was conducted to investigate the frequency of three gene polymorphisms in the 3'-untranslated region (3'-UTR) of human leucocyte antigen-G (HLA-G) gene in south Indian patients with rheumatoid arthritis (RA) and analyze their influence on disease susceptibility, phenotype and treatment response. HLA-G 14 bp insertion (Ins)/deletion (del) (rs66554220), HLA-G +3142G>C (rs1063320) and +3187A>G (rs9380142) polymorphism was analyzed in 221 RA patients and 200 healthy controls. Frequency of HLA-G genotypes or alleles did not differ between patients and controls. Analysis based on rheumatoid factor (RF) status revealed that the frequency of allele 'A' (rs9380142) was significantly higher in RF-positive than in RF-negative patients [84% vs 74%, Yates-corrected P value (Pc) = 0.04, odds ratio (OR) = 1.8, 95% confidence interval (CI) = 1.0-3.2]. A similar difference was maintained in RF-positive female patients than their RF-negative counterparts (83% vs 71%, Pc = 0.02, OR = 1.9, 95% CI = 1.0 to 3.4) and between RF-positive and RF-negative young onset RA (YORA) patients (84% vs 73%, Pc = 0.03, OR = 1.9, 95% CI = 1.0-3.2), suggesting that rs9380142 polymorphism influenced RF status. The 14 bp Ins allele of rs66554220 was significantly more prevalent in RF-positive YORA than in RF-positive late onset RA (LORA) patients (51% vs 25%, P = 0.03, OR = 3.1, 95% CI = 1.1-9.8). Frequency of the four major haplotypes [InsGA (48%), DelGA (22%), DelCG (18%), DelCA (9.7%)] observed did not differ between cases and controls. HLA-G does not appear to be a risk factor for development of RA in south Indian Tamils but may act as a genetic modifier of clinical phenotype in terms of autoantibody production, gender preference and age at disease onset.

IRF5rs2004640 single nucleotide polymorphism is associated with susceptibility to rheumatoid arthritis in South Indian Tamils

Polymorphism of interferon regulatory factor 5 (IRF5), a latent transcription factor gene has been associated with various auto-immune diseases. Our aim was to study the IRF5rs2004640 gene polymorphism and its association with disease susceptibility, disease phenotype and treatment response in South Indian Tamil patients with rheumatoid arthritis (RA).The study was conducted on 217 RA patients fulfilling the American College of Rheumatology (ACR) 2010 criteria and 482 healthy controls (HCs) without family history of autoimmune disease. The IRF5rs2004640 genotyping was performed using a TaqMan 5' allelic discrimination assay. We found that the IRF5rs2004640T allele [P < 0.0001, odds ratio (OR) 3.25, 95% confidence interval (CI) 2.55-4.12] and TT genotype (P < 0.0001, OR 4.60, 95% CI 3.23-6.57) were significantly more frequent in RA patients as compared with HCs. No association was found between IRF5rs2004640 polymorphism, clinical manifestations, autoantibody profile and treatment response. IRF5rs2004640 T (mutant) allele may be a susceptibility factor conferring risk for RA in South Indian Tamils, whereas G allele (wild type) may be protective.

Clinical and molecular findings of chronic granulomatous disease in Oman: family studies

Chronic granulomatous disease (CGD), a rare inherited disorder of the innate immune system, results from mutations in any one of the five genes encoding the subunits of the nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) oxidase enzyme, and is characterized by recurrent life-threatening bacterial and fungal infections. Molecular analysis of 14 Omani CGD patients from 10 families, diagnosed to have CGD on clinical (recurrent infections) and biochemical grounds (positive for both the nitroblue tetrazolium (NBT) test and the dihydrorhodamine (DHR-1,2,3 assay), revealed that only one patient had X-linked CGD, with a large deletion involving both the gp91-phox gene (CYBB) and the McLeod gene (XK). The remaining 13 patients were all homozygotes from a previously described c.579G>A (p.Trp193X) mutation in the NCF1 gene on chromosome 7, responsible for autosomal recessive CGD (AR-CGD). Although X-linked CGD is the most common type of CGD disorder in most population groups, AR-CGD is the most prevalent type in Oman.

Description of a new species, Toxorhynchites (Toxorhynchites) tyagii (Diptera: Culicidae), from Nilgiri hills, Western Ghats, southern India

Specimens of Toxorhynchites (Toxorhynchites) tyagii, sp. n., were collected from the fringe areas of Gudaloor town, Ooty in the Nilgiri hills at an altitude of 1000 m above sea level in Western Ghats ranges in southern India during October 2011 and from Darjeeling ranges in the northern hilly region of Raymatang TG in Jalpaiguri district, West Bengal, in eastern India during February 2012. The adults, pupa and fourth-instar larva of this species are described and illustrated to distinguish it from Toxorhynchites (Tox.) splendens and Toxorhynchites (Tox.) edwardsi, which are the closest allies of Tx. (Tox.) tyagii. Besides possessing remarkable distinguishing male genital characteristics, Tx. tyagii differs from Tx. splendens also by the presence of conspicuous yellow scale-patches over the wing root that extend to the scutellum, and differs from Tx. edwardsi by having midtarsomeres 3-5 all dark whereas in Tx. edwardsi tarsomeres 3 and 4 and a larger part of 5 are white.

Molecular characteristics of Human Endogenous Retrovirus type-W in schizophrenia and bipolar disorder

Epidemiological and genome-wide association studies of severe psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BD), suggest complex interactions between multiple genetic elements and environmental factors. The involvement of genetic elements such as Human Endogenous Retroviruses type 'W' family (HERV-W) has consistently been associated with SZ. HERV-W envelope gene (env) is activated by environmental factors and encodes a protein displaying inflammation and neurotoxicity. The present study addressed the molecular characteristics of HERV-W env in SZ and BD. Hundred and thirty-six patients, 91 with BD, 45 with SZ and 73 healthy controls (HC) were included. HERV-W env transcription was found to be elevated in BD (P<10-4) and in SZ (P=0.012) as compared with HC, but with higher values in BD than in SZ group (P<0.01). The corresponding DNA copy number was paradoxically lower in the genome of patients with BD (P=0.0016) or SZ (P<0.0003) than in HC. Differences in nucleotide sequence of HERV-W env were found between patients with SZ and BD as compared with HC, as well as between SZ and BD. The molecular characteristics of HERV-W env also differ from what was observed in Multiple Sclerosis (MS) and may represent distinct features of the genome of patients with BD and SZ. The seroprevalence for Toxoplasma gondii yielded low but significant association with HERV-W transcriptional level in a subgroup of BD and SZ, suggesting a potential role in particular patients. A global hypothesis of mechanisms inducing such major psychoses is discussed, placing HERV-W at the crossroads between environmental, genetic and immunological factors. Thus, particular infections would act as activators of HERV-W elements in earliest life, resulting in the production of an HERV-W envelope protein, which then stimulates pro-inflammatory and neurotoxic cascades. This hypothesis needs to be further explored as it may yield major changes in our understanding and treatment of severe psychotic disorders.

Is it essential to inform the positive donor? A 2-year study in a tertiary care hospital

Background:

In India, screening of blood for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV) is mandatory before issue, but the donors are often not informed of their positive status.[1] The positive donors are always kept in dark. Is it essential to inform the positive donor? It is a debate still.

Materials and Methods:

Sri Ramachandra Blood Bank, Chennai, took the challenge of posttest counseling of blood donors from June 2008. Blood collected from donors were screened for HIV, HBsAg, and HCV. The donors of the blood, which are positive by two different enzyme-linked immunosorbent assay for any of the above tests, were sent a letter of calling respecting their rights and maintaining confidentiality. Responded donors were given counseling and offered information about confirmation, evaluation, consultation, early treatment, follow-up, contact testing, and transmission prevention. The results were analyzed for a period of 2 years from June 2008 to May 2010.

Results:

Among the 22,573 donors, 355 (1.7%) were found to be positive in the screening tests. Letters of calling were sent to 310 (87.04%) donors. In all, 218 (70.3%) donors with 7 (87.5%) HIV, 199 (68.85%) HBsAg, and 12 (92.31%) HCV positivity responded. None of the responded donors knew their status earlier. In all, 82 (35%) of them were repeat donors with 201 earlier donations at various blood banks.

Conclusion:

Posttest counseling of positive donors is essential for the health of the donor and his family, prevention of diseases, improving blood bank economy, and reducing exposure to healthcare workers.

Estimation of ²¹⁰Po and ²¹⁰Pb and its dose to human beings due to consumption of marine species of Ennore Creek, South India

A systemic study on the natural radionuclides such as (210)Po and (210)Pb in the environmental matrices and biota of Ennore Creek has been undertaken to establish a baseline data on the radiation profile of Ennore Creek environment. The environmental samples such as water, sediment, and biota (seaweeds, molluscs, crustaceans, and fishes) have been subjected to analyses. It has been observed that the concentration of (210)Po and (210)Pb in the water samples of Ennore Creek as 2.7 and 1.63 m Bq L(-1), respectively. The activity concentration of (210)Po and (210)Pb in the sediment sample was 17.9 and 28.9 Bq kg(-1), respectively. The bivalve mollusk Perna viridis have been identified to accumulate higher concentrations of (210)Po and (210)Pb suggesting that they could serve as bioindicator of radionuclides in the Ennore Creek environment. The committed effective dose for human beings was found at 81.13-216.8 and 2.1-297.2 μSv year(-1) for (210)Po and (210)Pb, respectively.

Degloving injuries of the hand

Avulsion of skin from the hand or fingers is an injury that has a dramatic presentation. The entire musculo-skeletal unit of the finger is intact, and the patient can often move the parts of his naked hand quite normally. The challenge for the reconstructive surgeon lies in resurfacing the hand or finger with a good quality pliable sensate skin cover while preserving the movements and function of the hand. Traditionally, skin grafting has been the standard method of reconstruction in such injuries. However, skin grafting does have many disadvantages, too. This article deals with the features of such injuries, management protocols and other reconstructive options available in the armamentarium of the hand surgeon.

Distribution of CYP2C19*17 allele and genotypes in an Indian population

WHAT IS KNOWN AND OBJECTIVE

CYP2C19*17 allele increases the metabolic activity of CYP2C19 resulting in decreased therapeutic levels of CYP2C19 substrates. There exist inter-ethnic differences in the distribution of this allele. The present study was aimed at establishing the allele and genotype frequencies of CYP2C19*17 in a South Indian Tamilian population. Furthermore, we describe the haplotype structure of the three common variant alleles of CYP2C19 in the Tamilian population.

METHODS

Two hundred and six subjects of South Indian Tamilian origin were genotyped for CYP2C19*17 allele by nested polymerase chain reaction and restriction fragment length polymorphism. A subset of 87 subjects were also genotyped for CYP2C19*2 and CYP2C19*3 alleles. After ascertaining linkage disequilibrium (LD), haplotypes were constructed. Allele and genotype frequencies, LD pattern and haplotype frequency were compared with those of the HapMap populations.

RESULTS AND DISCUSSION

The CYP2C19*17 allele frequency in the Tamilian population (n = 206) was found to be 19·2% (95% CI: 15·4 - 20·3). The CYP2C19*2 allele frequency (n = 87) was found to be 40·2% (95% CI: 32·9 - 47·5), whereas the CYP2C19*3 allele was not detected in the study subjects (n = 97). The high frequency of the CYP2C19*17 allele in the study population has resulted in a revision of frequencies for CYP2C19*1/*2 (31·0%) and CYP2C19*1/*1 (16·1%) genotypes in the Tamilian population. We also observed significant differences in haplotype structure and frequencies of these variant alleles in the HapMap population compared to Tamilian population.

WHAT IS NEW AND CONCLUSION

CYP2C19*17 allele is present at high frequency in the Tamilian population. This study also demonstrates the need for reassessment of wild-type allele frequencies in view of CYP2C19*17 allele. The estimated high frequency of CYP2C19*17 allele will aid in genotype-phenotype association studies in the Tamilian population. Further genotype-phenotype association studies are required to evaluate the clinical utility of this allele in South Indians.

Association of IL-12p40 +1188 A/C polymorphism with nasopharyngeal cancer risk and tumor extension

The interleukin 12 (IL-12) cytokine, encoded by polymorphic genes, plays a central role in the T helper 1 cell-mediated immunity against tumors. We investigated whether the 3' untranslated region +1188 A/C polymorphism (rs 3212227) influences the nasopharyngeal carcinoma (NPC) risk in Tunisian patients. DNA analysis of 247 patients and 284 healthy individuals showed a higher frequency of the 1188 C allele and the CC genotype in patients than in controls (P = 0.00001 and P = 0.00005) suggesting that the C variant allele is associated with the susceptibility to NPC. Additional testing showed that the homozygous CC genotype is also associated with advanced stage of the tumor extension at presentation (P = 0.022). Our data suggest that the impaired production of IL-12 behaves as a risk factor for NPC occurrence and progression.

Cholestasis and biliary dilatation associated with chronic ketamine abuse: a case series

Ketamine is a dissociative anaesthetic agent that is still widely used in veterinary and human medicine. It is increasingly being used as a recreational hallucinogenic drug. Chronic ketamine abuse is known to account for lower urinary tract symptoms and urinary bladder dysfunction. There is now emerging evidence that ketamine misuse is also associated with abnormal liver function tests and biliary tract abnormality. We report three cases of chronic ketamine misuse in three young men who all presented with obstructive jaundice and biliary tract abnormality. We also describe the clinical features, radiological findings and potential underlying mechanisms for this new entity.

Heavy metals in two fish species (Carangoidel malabaricus and Belone stronglurus) from Pulicat Lake, North of Chennai, Southeast Coast of India

We present the results from a detailed study based on five metals (Cr, Cd, Zn, Pb and Fe) measured in four organs (gills, liver, intestine and muscle) of two fish species (Carangoidel malabaricus and Belone stronglurus) from Pulicat Lake in southeast coast of India. The results show marked differences between the two species and organs as well as significant variations within the five analyzed metals. Although the metal concentrations measured in fish muscle are low, high levels of Pb and Fe were observed in the liver and gills of the two fish species. The concentrations of heavy metals in edible parts (muscle) of fish were within the permissible levels and are safe for the human consumption.

Temperature effect on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the fish fingerlings of Alepes djidaba

The present study has been carried out to determine the effect of temperature on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the fish fingerlings of Alepes djidaba, which were collected at Kalpakkam. The fish fingerlings were placed at different temperatures, based on the thermal tolerance limit of fish and thermal outfall of the Madras Atomic Power Station (MAPS). The thermal tolerance experiments were conducted in two ways: in direct exposure and in gradually increasing temperature for duration of 48 hr. The upper and lower lethal temperatures for the fish fingerlings of Alepes djidaba were 38.5 degrees C and 14 degrees C respectively. During tolerance experiment, no mortality was observed at 33 degrees C and 35 degrees C. But at 38 degrees C with gradual increase in temperature, 100% loss of equilibrium was observed at 37.7 degrees C in 36 min and mortality was observed at 38 degrees C in 55 min. On the contrary, when the fish fingerlings A. djidaba were directly exposed to 38 degrees C, almost 100% loss of equilibrium and mortality were recorded in 15 min and 31 min respectively. At 40 degrees C with gradual increase in temperature, 100% loss of equilibrium was recorded at 38.5 degrees C in 46 min and mortality was recorded at 39 degrees C in 50 min. On the other hand, when the fish fingerlings of Alepes djidaba were directly exposed to 40 degrees C, 100% mortality occurred immediately within one minute. These behavioral responses include an elevated temperature of deltaT 10 degrees C, surfacing, dashing against glass wall, jumping out of the water, etc. In general, the rate of oxygen consumption and ammonia excretion was found to enhance with increasing temperature. The oxygen consumption was found to increase from 0.97 mg O2/g/hr at 30 degrees C to 2.2 mg O2/g/hr at 35 degrees C. Similarly, the excretion of ammonia also increased from 3.18 microg/g/hr at 30 degrees C to 5.91 microg/g/hr at 35 degrees C. In the present study, it was found that gradual increase in temperature favours the fish population to escape from the thermal exposure as compared to direct exposure, and also the temperature impact due to thermal discharge from MAPS is only minimal (35 degrees C) and no mortality could be caused to the fish population.

Temperature effect on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the post larvae of shrimp Penaeus indicus

The present study has been carried out to know the effect of temperature on behaviour, equilibrium loss and tolerance limit of the post larvae of shrimp Penaeus indicus. The experimental temperatures were selected based on the thermal tolerance limit. The experiments were conducted at a specific temperature for duration of 48 hr. The thermal tolerance experiments were conducted in two ways: in direct exposure and in gradually increasing temperature. The upper and lower lethal temperatures for the post larvae of shrimp P. indicus were 43.5 degrees C and 8 degrees C respectively. During tolerance experiment, no mortality was observed at 33 degrees C and 35 degrees C. But at 38 degrees C with gradual increase in temperature, 30% loss of equilibrium and mortality were recorded in 24.31 hrs and 25.07 hrs, and the remaining 70% were alive. On the contrary, when the post larvae of shrimps were directly exposed to 38 degrees C, almost 80% loss of equilibrium and mortality were recorded in 30.22 hrs and 30.40 hrs, remaining 20% were alive. At 40 degrees C with gradual increase in temperature, 100% loss of equilibrium and mortality were recorded in 25.32 hrs and 25.56 hrs. On the other hand, when the post larvae of shrimps were directly exposed to 40 degrees C, 100% loss of equilibrium was observed in 0.37 hrs and mortality in 1.40 hrs. These behavioral responses include an elevated temperature of 12 degrees C, surfacing, dashing against glass wall, jumping out of the water, etc. In general, the rate of oxygen consumption and ammonia excretion was found to enhance with increasing temperature. In the present study, it was found that gradual increase in temperature favours the shellfish population to escape from the thermal exposure as compared to direct exposure.

Constitutive nitric oxide synthase gene polymorphisms and house dust mite respiratory allergy in an Algerian patient group

Genetic polymorphisms in neuronal nitric oxide synthase (NOS1) and calmodulin-dependent endothelial NOS (NOS3) genes are known to influence the course of allergic respiratory disorders. We investigated the role of NOS1 -84 G-->A and NOS3 -786 T-->C, 894 G-->T and 27 base pair (bp) repeat polymorphisms in 125 patients suffering from asthma and/or rhinitis and monosensitized against Dermatophagoides pteronyssinus (Dpter) and 111 controls from Algeria. We found a higher frequency of the -786 C NOS3 allele in patients than in controls [corrected P value (Pc) = 0.04], especially in female cases (Pc = 0.02) and that the 'ab' genotype of the 27-bp polymorphism was significantly associated with specific immunoglobulin E production against Dpter (P = 0.006). This study brings further support for the participation of NOS3 gene polymorphism in the pathogenesis of respiratory allergic disorders.