Environmental DNA in human and veterinary parasitology - Current applications and future prospects for monitoring and control.

Parasites are important pathogens with significant global economic, public and animal health impacts. Successful control or elimination of many parasitic diseases, not least neglected tropical parasites, will require scalable, sensitive and cost-effective monitoring tools. Environmental DNA (eDNA) methods, used extensively in ecology for biomonitoring in natural ecosystems, offer promising advantages such reduced costs and labor requirements for species monitoring. Yet, the use of eDNA-based methods in parasitology and disease surveillance, has only recently begun to be explored. With this review, we wish to give an up-to-date overview of current uses and limitations of eDNA in human and veterinary parasitology, and how existing challenges can be overcome to fully utilize the potential of eDNA for monitoring and control of parasitic diseases. We begin by systematically searching published literature to identify studies that apply eDNA methods in parasitology and synthesize the main findings from these studies. We find that eDNA applications in parasitology only account for a small proportion (73/1960) of all eDNA publications up to now, and even fewer (27/73) studies, that apply eDNA methods specifically for parasites of human or veterinary importance. The majority of studies concern snail-borne trematodes and their intermediate host snails, while a few apply eDNA for mosquito vector species detection. A strong geographical bias, with only very few studies undertaken on the African continent, where parasites are of the biggest public health concern, is also noted. Current obstacles hindering further advances of eDNA methods in parasitology include incomplete reference databases, and challenges related to real-time monitoring in remote areas, and in certain LMIC settings. Finally, we point to future opportunities for eDNA-based research in parasitology and highlight recent innovations in eDNA research, which could further develop its application for monitoring and control of parasitic diseases and vectors in the future.

Sero-prevalence and risk factors of Toxoplasma gondii infection in wild cervids in Denmark.

Toxoplasma gondii is a zoonotic protozoan parasite capable of infecting possibly all warm-blooded animals including humans, and is one of the most widespread zoonotic pathogens known. Free-ranging wildlife can be valuable sentinels for oocyst contaminated environments, as well as a potential source for human foodborne infection with T. gondii. Here we aimed to determine the sero-prevalence of T. gondii in Danish wild deer populations and examine risk factors associated with increased exposure to the parasite. Blood samples were collected from 428 cervids (87 fallow deer (Dama dama), 272 red deer (Cervus elaphus), 55 roe deer (Capreolus capreolus) and 14 sika deer (Cervus Nippon) from 23 hunting sites in Denmark. The animals were shot during the hunting season 2017/2018, and screened for antibodies against T. gondii using a commercial ELISA kit. One hundred and five (24.5%) cervids were sero-positive. Sero-prevalence was significantly different between species (p < 0.05), with odds of sero-positivity being 4.5 times higher in roe deer than fallow deer, and 3.0 times higher in red deer than in fallow deer. A significant increase in sero-prevalence with age was observed, driven by a significant increase in risk in adult red deer compared to calves (OR: 13.22; 95% CI: 5.96-33.7). The only other significant risk factor associated with wild cervid T. gondii sero-positivity was fencing, with the highest exposure associated with deer from non-fenced hunting areas (OR: 2.21; 95% CI: 1.05-4.99). This study documented a widespread exposure to T. gondii in Danish cervids. Therefore the meat of the wild deer, in particular from roe deer and red deer, should be considered a significant risk of T. gondii infections to humans, if not properly cooked. Further, molecular studies to confirm the presence of infective parasitic stages in the muscles of deer used for consumption is recommended.

Fatigue in systemic lupus: the role of disease activity and its correlates.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that leads to a variety of negative health outcomes resulting from inflammation in various organ systems. Although treatment continues to advance, fatigue remains one of the most salient, poorly understood and addressed patient complaints. Understanding the mechanisms of fatigue can help guide the development of interventions to improve health outcomes. The aim of this research was to evaluate the contribution of six variables (disease activity, insomnia, depression, stress, pain and physical health) to fatigue in SLE without concomitant fibromyalgia (FM). METHODS: A total of 116 ethnically diverse, primarily female participants (91%) with SLE, receiving care at university medical centers, completed assessments of disease activity and quality of life outcomes (FACIT-FT, Insomnia Severity Index, Perceived Stress Scale (PSS-4), Pain Inventory, Depression-PHQ-9, and LupusPRO-physical function). All patients met the American College of Rheumatology classification criteria for SLE and did not have a known diagnosis of FM. Multivariate linear and stepwise regression analyses were conducted with fatigue (FACIT-FT) as the dependent variable, and the above six variables as independent variables. RESULTS: Mean (SD) age was 39.80 (13.87) years; 50% were African American, 21% Caucasian, 13% Hispanic, 9% Asian and 8% other. Mean (SD) FACIT-FT was 20.09 (12.76). Collectively, these six variables explained 57% of the variance in fatigue. In the multivariate model, depression, stress and pain were significantly and independently associated with fatigue, but not disease activity, sleep or physical health. Stress had the largest effect on fatigue (ß 0.77, 95% CI 0.17-1.38, p = 0.01), followed by depression (ß 0.66, 95% CI 0.21-1.10, p = 0.005). On stepwise regression analysis, only stress, depression and pain were retained in the model, and collectively explained 56% of the variance in fatigue. All three remained independent correlates of fatigue, with the largest contribution being stress (ß 0.84, 95% CI 0.27-1.42, p = 0.005), followed by depression (ß 0.79, 95% CI 0.44-1.14, p < 0.001) with fatigue. CONCLUSION: Stress, depression and pain are the largest independent contributors to fatigue among patients with SLE, without concurrent FM. Disease activity, sleep and physical health were not associated with fatigue. The evaluation of stress, depression and pain needs to be incorporated during assessments and clinical trials of individuals with SLE, especially within fatigue. This stress-depression-fatigue model requires further validation in longitudinal studies and clinical trials. Significance and innovation: • Disease activity, sleep, pain, stress, depression, and physical health have been reported individually to be associated with fatigue in lupus. This analysis evaluated the role of each and all of these six variables collectively in fatigue among patients with SLE without a known diagnosis of FM. • Disease activity, sleep and physical health were not significantly related to fatigue, but depression, stress and pain were. • The results emphasize the need to evaluate and treat fatigue in individuals with SLE utilizing a biopsychosocial approach, particularly in the realm of clinical trials. Behavioral medicine interventions are shown to be most effective for the treatment of depression, stress and pain.

Functional assessment of tyrosinase variants identified in individuals with albinism is essential for unequivocal determination of genotype-to-phenotype correlation.

BACKGROUND: Oculocutaneous albinism type 1 (OCA1), caused by pathogenic variations in the tyrosinase gene (TYR), is the most frequent and severe form of hypopigmentary disorder worldwide. While OCA1A manifests as a complete loss of melanin pigment, patients with OCA1B show residual pigmentation of the skin, hair and eyes. Limited experimental evidence suggests retention of TYR in the endoplasmic reticulum (ER) causes OCA1 pathogenesis. However, a comprehensive functional analysis of TYR missense variations and correlation with genotype is lacking. OBJECTIVES: Functional characterization of nonsynonymous tyrosinase variants in patients with OCA1 reported in the Albinism Database, dbSNP and the published literature, and an attempt to correlate them with reported and predicted phenotypes. METHODS: Thirty-four reported missense variants of TYR were subcloned by site-directed mutagenesis, and the dual-enzyme activities of the variant proteins were compared with the wild-type. The degree of ER retention was also checked for each of the variants through endoglycosidase H (Endo H) digestion followed by immunoprecipitation and densitometric analysis. RESULTS: Functional studies revealed one reported OCA1A variation with nearly 100% enzyme activity, 10 OCA1B variants lacking any enzyme activity, eight nonsynonymous single-nucleotide polymorphisms (SNPs) with ~30-70% of enzyme activity, and three SNPs that completely lacked activity altogether. The Endo H assay corroborated these results. CONCLUSIONS: Loss of enzyme activity of TYR variants was completely in agreement with ER retention across all variants examined. The results of the assay clearly established that determination of the biological activity of identified variants in patients with OCA is essential to correlate the identified suspect genotype with the obvious phenotype of the disease.

In silico analyses of missense mutations in coagulation factor VIII: identification of severity determinants of haemophilia A.

Factor VIII (FVIII) mutations cause haemophilia A (HA), an X-linked recessive coagulation disorder. Over 1000 missense mutations in FVIII are known and they lead to variable clinical phenotypes (severe, moderate and mild). The exact molecular basis of this phenotypic heterogeneity by FVIII missense mutations is elusive to date. In this study, we aimed to identify the severity determinants that cause phenotypic heterogeneity of HA. We compiled and curated a data set of 766 missense mutations from the repertoire of missense mutations in FVIII. We analysed these mutations by computational programs (e.g. Swiss-PdbViewer) and different mutation analysis servers (e.g. SIFT, PROVEAN, CUPSAT, PolyPhen2, MutPred); and various sequence- and structure-based parameters were assessed for any significant distribution bias among different HA phenotypes. Our analyses suggest that 'mutations in evolutionary conserved residues', 'mutations in buried residues', mutation-induced 'steric clash' and 'surface electrostatic potential alteration' act as risk factors towards severe HA. We have developed a grading system for FVIII mutations combining the severity determinants, and the grading pattern correlates with HA phenotype. This study will help to correctly associate the HA phenotype with a mutation and aid early characterization of novel variants.

Regulation of Streptococcus mutans PTS Bio by the transcriptional repressor NigR.

Streptococcus mutans is implicated in human dental caries, and the carbohydrate metabolism of this organism plays an important role in the formation of this disease. Carbohydrate transport and metabolism are essential for the survival of S. mutans in the oral cavity. It is known that a unique phosphoenolpyruvate-sugar phosphotransferase system PTS(B) (io) of S. mutans UA159 is expressed in sucrose-grown biofilms (Mol Oral Microbiol 28: 2013; 114). In this study we analyzed the transcriptional regulation of the operon (O(B) (io) ) encoding the PTS(B) (io) and showed that it was repressed by NigR, a LacI-like transcriptional regulator. Using electro-mobility shift assay, we described two operators to which NigR bound with different affinities. We also identified the transcriptional start site and showed that one of the operators overlaps with the promoter and presumably represses initiation of transcription. Mutational analyses revealed the key nucleotides in the operators required for high-affinity binding of NigR. PTS(B) (io) is expressed in S. mutans biofilms so understanding its regulation may provide improved strategies for caries treatment and prevention.

Molecular basis of albinism in India: evaluation of seven potential candidate genes and some new findings.

Albinism represents a group of genetic disorders with a broad spectrum of hypopigmentary phenotypes dependent on the genetic background of the patients. Oculocutaneous albinism (OCA) patients have little or no pigment in their eyes, skin and hair, whereas ocular albinism (OA) primarily presents the ocular symptoms, and the skin and hair color may vary from near normal to very fair. Mutations in genes directly or indirectly regulating melanin production are responsible for different forms of albinism with overlapping clinical features. In this study, 27 albinistic individuals from 24 families were screened for causal variants by a PCR-sequencing based approach. TYR, OCA2, TYRP1, SLC45A2, SLC24A5, TYRP2 and SILV were selected as candidate genes. We identified 5 TYR and 3 OCA2 mutations, majority in homozygous state, in 8 unrelated patients including a case of autosomal recessive ocular albinism (AROA). A homozygous 4-nucleotide novel insertion in SLC24A5 was detected in a person showing with extreme cutaneous hypopigmentation. A potential causal variant was identified in the TYRP2 gene in a single patient. Haplotype analyses in the patients carrying homozygous mutations in the classical OCA genes suggested founder effect. This is the first report of an Indian AROA patient harboring a mutation in OCA2. Our results also reveal for the first time that mutations in SLC24A5 could contribute to extreme hypopigmentation in humans.

The SLE-associated Pbx1-d isoform acts as a dominant-negative transcriptional regulator.

Pbx1 is a transcription factor involved in multiple cellular processes, including the maintenance of self-renewal of hematopoietic progenitors. We have shown that the CD4(+) T-cell expression of a novel splice isoform of Pbx1, Pbx1-d, is associated with lupus susceptibility in the NZM2410 mouse and in lupus patients. The function of Pbx1 in T cells is unknown, but the splicing out of the DNA-binding domain in Pbx1-d predicts a dominant-negative function. In support of this hypothesis, we have shown that Pbx1-d transduction accelerates differentiation of MC3T3-E1 osteoblast pregenitors and mimics the effect of short hairpin RNA silencing of Pbx1. Conversely, Pbx1-d transduction reduced the expression of Sox3, a gene strongly transactivated by Pbx1, and Pbx1-d did not bind the Sox3 promoter. These results constitute a first step towards the understanding on how Pbx1-d contributes to systemic autoimmunity in the NZM2410 mouse model as well as in lupus patients.

Quantitative dermatoglyphic asymmetry: a comparative study between schizophrenic patients and control groups of West Bengal, India.

Quantitative Fluctuating (FA) and Directional asymmetry (DA) of dermatoglyphics on digito-palmar complex were analyzed in a group of 111 patients (males: 61, females: 50) with schizophrenia (SZ), and compared to an ethnically matched phenotypically healthy control (males: 60, females: 60) through MANOVA, ANOVA and canonical Discriminant analyses. With few exceptions, asymmetries are higher among patients, and this is more prominent in FA than DA. Statistically significant differences were observed between patient and control groups, especially in males. In both sexes, FA of combined dermatoglyphic traits (e.g. total finger ridge count, total palmar pattern ridge count) are found to be a strong discriminator between the two groups with a correct classification of over 83% probability.

Comprehensive analysis of the molecular basis of oculocutaneous albinism in Indian patients lacking a mutation in the tyrosinase gene.

BACKGROUND: Oculocutaneous albinism (OCA) refers to a group of inherited disorders where the patients have little or no pigment in the eyes, skin and hair. Mutations in genes regulating multi-step melanin biosynthesis are the basis of four 'classical' OCA types with overlapping clinical features. There are a few reports on defects in TYR and a single report on SLC45A2 in Indians affected with OCA but no report on OCA2 (a major locus related to the disease) and TYRP1. OBJECTIVES: To assess and describe a comprehensive picture of the molecular genetic basis of OCA among Indians with no apparent mutations in TYR. METHODS: Twenty-four affected pedigrees from 14 different ethnicities were analysed for mutations in OCA2, TYRP1, SLC45A2 and SLC24A5 using the polymerase chain reaction-sequencing approach. RESULTS: Two splice-site and four missense mutations were detected in OCA2 in seven unrelated pedigrees, including four novel mutations. Haplotype analysis revealed a founder mutation (Ala787Thr) in two unrelated families of the same ethnicity. A patient homozygous for a novel SLC45A2 mutation also harboured a novel OCA2 defect. No mutation was detected in TYRP1 or SLC24A5. CONCLUSIONS: Our results suggest that an OCA2 gene defect is the second most prevalent type of OCA in India after TYR. The presence of homozygous mutations in the affected pedigrees underscores the lack of intermixing between the affected ethnicities. Direct detection of the genetic lesions prevalent in specific ethnic groups could be used for carrier detection and genetic counselling to contain the disease.

Prevalence and significance of antiphospholipid antibodies in selected at-risk obstetrics cases: a comparative prospective study.

In a prospective comparative study we screened 112 women with a past history either of pre-eclampsia, eclampsia, recurrent abortion, IUGR, IUFD or abruptio placentae, with no apparent aetiology and a demographically matched cohort of 106 women having a past history of uncomplicated pregnancy outcome for the presence of antiphospholipid antibodies (aPL) and their significance. In the former group, the prevalence of aPL ranged from 10-46.87% compared with 8.49% in the later group. In women with the presence of aPL, the incidence of pre-eclampsia, early onset pre-eclampsia and abruptio placentae were 25%, 14.58% and 18.75%, respectively. In the same group, the abortion rate was 25% and live-birth rate was 64.58% with IUFD rate of 10.42%. Fetal morbidity rates were also higher in the mothers with aPL positivity, the incidence of IUGR was 27.08% and oligohydramnios was 33.33% in them. All these complications were statistically significant when compared with those of aPL negative mothers.

Arsenic speciation in rice, straw, soil, hair and nails samples from the arsenic-affected areas of Middle and Lower Ganga plain.

In the present study, pressurised liquid extraction and ultrasound probe sonication, for the latter in combination with a mixed enzymatic treatment in case of rice and straw samples, were applied as sample preparation prior to arsenic speciation analysis by high pressure liquid chromatography coupled to inductively coupled plasma mass spectrometric detection (HPLC-ICP-MS). A significant number of samples as different as rice, straw, soil, nail and hair, all coming from the heavily arsenic-contaminated Middle and Lower Ganga plain area, could be investigated with validated methods, supported by high speed extraction methods. For rice and paddy samples, inorganic arsenic counted up to 70-98% of the total arsenic content, being the major species As (III). The levels of arsenic obtained from straw and soil samples are significantly higher than the background levels, being the major species As (V), thus increasing human exposure to arsenic via the soil-plant-animal-human pathway. Concentrations found in hair and nails were significantly higher than their background levels: 39- and 20-fold for hair and nails, respectively. These samples contained mainly inorganic arsenic in its tri- and pentavalent forms. Results indicate that, under the local frame conditions, arsenic mainly enters into the food chain via its more problematic inorganic forms. Arsenic speciation analysis proves to be a powerful tool for a complete analytical assessment in epidemiological studies covering the endemic areas.

Genetics of dermatoglyphic asymmetry in Vaidyas of West Bengal, India.

In this study of the genetics of dermatoglyphic asymmetry, we collected bilateral finger and palm prints of 824 individuals from 200 families including 2 generations from an endogamous caste (Vaidya) in Barasat, North 24-Parganas District, West Bengal. Two main types of asymmetry (fluctuating asymmetry and directional asymmetry) were calculated between the two hands. The study includes familial correlation between first-degree relatives, principal-components analysis, and maximum-likelihood-based heritabilities (by pedigree analysis). We found, first, that familial correlations in all possible pairs of relationships (except spouse correlation) were weak but positive; some were even statistically significant. No indication of assortative mating was observed, but the influence of maternal environment could not be discarded. The results also showed that X-chromosome linkage does not seem to be involved. A second major finding is that five principal factors could be extracted from all these asymmetric traits, explaining 74.207% of the overall cumulative variance. Asymmetry of finger and palmar areas were clearly separated by factor. In addition, the heritabilities of the extracted five factors were in the range of 8-24%. These estimates are in agreement with some previously published data. The heritabilities of the factors describing palmar asymmetry are slightly lower than those describing finger asymmetry. The present results support the hypothesis that both types of asymmetry have a genetic basis and are influenced by the intrauterine environment.

OCA1 in different ethnic groups of india is primarily due to founder mutations in the tyrosinase gene.

Oculocutaneous albinism (OCA) is a heterogeneous group of autosomal recessive disorders characterized by an abnormally low amount of melanin in the eyes, skin and hair, and associated with common developmental abnormalities of the eye. Defects in the tyrosinase gene (TYR) cause a common type of OCA, known as oculocutaneous albinism type 1 (OCA1). The molecular basis of OCA has been studied extensively in different population groups, but very little information is available on Indian patients. Our investigation covering thirteen ethnic groups of India, some representing >20 million people, revealed that among 25 OCA families 12 were affected with OCA1, and that these cases were primarily due to founder mutations in TYR. We detected nine mutations and eight SNPs in TYR, of which six mutations (five point mutations & one gross deletion) were novel. In contrast to most reports describing compound heterozygotes, the presence of homozygotes in 10 out of the 12 pedigrees underscores the lack of intermixing between these ethnic groups in India. Haplotype analysis suggested a few founder chromosomes causing the disease in the majority of the patients. Direct detection of the mutations prevalent in specific ethnic groups could be used for carrier detection and genetic counselling.

Arsenic burden of cooked rice: Traditional and modern methods.

Arsenic contamination of rice by irrigation with contaminated groundwater and secondarily increased soil arsenic compounds the arsenic burden of populations dependent on subsistence rice-diets. The arsenic concentration of cooked rice is known to increase with the arsenic concentration of the cooking water but the effects of cooking methods have not been defined. We tested the three major rice cooking procedures followed globally. Using low-arsenic water (As < 3 microg/L), the traditional method of the Indian subcontinent (wash until clear; cook with rice: water::1:6; discard excess water) removed up to 57% of the arsenic from rice containing arsenic 203-540 microg/kg. Approximately half of the arsenic was lost in the wash water, half in the discard water. A simple inexpensive rice cooker based on this method has been designed and used for this purpose. Despite the use of low-arsenic water, the contemporary method of cooking unwashed rice at rice:water::1:1.5-2.0 until no discard water remains did not modify the arsenic content. Preliminary washing until clear did remove 28% of the rice arsenic. The results were not influenced by water source (tubewell, dug well, pond or rain); cooking vessel (aluminium, steel, glass or earthenware); or the absolute weight of rice or volume of water. The use of low-As water in the traditional preparation of arsenic contaminated rice can reduce the ingested burden of arsenic.

High signal in knee osteophytes is not associated with knee pain.

OBJECTIVE: Our understanding of the local source of pain in osteoarthritis (OA) remains unclear. We undertook this study to determine if the presence of high-signal osteophytes on magnetic resonance imaging (MRI) was associated with pain presence, location or severity. METHODS: Subjects were chosen from the Boston Osteoarthritis of the Knee Study, a natural history study of symptomatic knee OA. Assessments included knee MRI, pain assessments and information on weight and height. Osteophyte signal was defined as areas of increased signal intensity in the osteophyte on fat-suppressed T2 weighted images, and graded in the joint margins where osteophyte size is graded. All patients were evaluated with the frequent knee symptoms question for pain presence, the Western Ontario McMasters Osteoarthritis Index (WOMAC) for pain severity, and location of self-reported pain was recorded as present or absent based on locations identified on a standardized diagram. The osteophyte signal measures anywhere within one given knee were summed, creating an osteophyte signal aggregate. Logistic regression was conducted with quartile of osteophyte signal aggregate as the independent predictor and frequent knee symptom question as the dependent outcome. Association between quartile of osteophyte signal aggregate and pain severity on WOMAC was assessed using a linear regression. Logistic regression was used to evaluate the association between compartment-specific high-signal osteophytes aggregates (independent variable) and compartment-specific knee pain (dependent variable). Analyses were adjusted for gender, body mass index (BMI), and age. RESULTS: Two hundred and seventeen subjects were included in this analysis. They were predominantly male and 75% of subjects had radiographic tibio-femoral (TF) OA, and the remainder had patello-femoral (PF) radiographic OA. We did not find any association of high-signal osteophytes with presence of pain, pain severity or self-reported pain location. CONCLUSION: High-signal osteophytes detected on MRI are not associated with the presence of pain, pain severity or the self-reported location of pain.

Synergism in immunotoxicological effects due to repeated combined administration of arsenic and lead in mice.

Arsenic and lead are considered potent human hazards because of their neoplastic outcomes; increasing epidemiologic evidence indicates a link between heavy metal exposure and health risk. Since health risks of singly administered metals are well-established, in the present study we determined whether simultaneous repeated multimetal (arsenic + lead) exposure influences the development of immunotoxicity in mice exposed (in vivo) to lead acetate (10 mg/kg b.w.) and sodium arsenite (0.5 mg/kg b.w.) simultaneously. We report that in vivo multimetal exposure alters cell morphology, inhibits cell adhesion, nitric oxide release, intracellular killing ability, chemotactic migration, myeloperoxidase release, bacterial clearance from blood and spleen and increases DNA fragmentation. On measuring bacterial density in blood and spleen after 0, 24, 48 and 72 h post infection (with Staphylococcus aureus MC524) in control and multimetal treated groups, bacterial load showed delayed clearance from blood and spleen in the multimetal exposed group. We also found that in vivo exposure to the multimetal caused a decrease in cell adhesion, indicated by a fall in absorbance at 570 nm with respect to control. Exposure to multimetal led to morphological changes in macrophages, since more deformed cells were obtained in repeated combined exposure to arsenic and lead compared to control. Nitric oxide, which has a potent microbicidal activity in macrophages, was found to be released in fewer amounts in the multimetal exposed group from that of control group. It was observed that the viability of bacteria gradually decreased in control macrophage with time, whereas, in macrophages of multimetal exposed mice, the viability of S. aureus gradually increased. Chemotactic migration of splenic macrophages significantly decreased in the multimetal exposed group from that of control. Lysosomal enzyme release from splenic macrophages decreased upon simultaneous exposure to arsenic and lead, as is evident from the decrease in myeloperoxidase release in multimetal group from that in control. That the structural integrity of splenic macrophages is decreased in the multimetal exposed group is also evident from the enhanced percentage of DNA fragmentation after multimetal exposure, suggesting apoptotic death of splenic macrophage. Intracellular viable bacteria in the splenic macrophage from multimetal exposed group was 89.16 +/- 3.54% while that from control group was 49.19 +/- 1.16%, whereas single metal exposed groups showed a bacterial viability of 69.6 +/- 2.45% and 71.71 +/- 1.89% in arsenic and lead treated groups respectively. What is essentially noteworthy from the observed results is that lead and arsenic causes a greater immunotoxic effect when administered together as multimetal than when singly administered. Simultaneous exposure to lead and arsenic appears to be additive as is further established from the isobologram constructed by plotting the concentration of arsenic against the concentration of lead at which effect (in this case myeloperoxidase release) remained constant, a convex line showing synergism was demonstrated. The present study reports a definite synergistic trend of immunotoxicity during simultaneous exposure to arsenic and lead, that is, a multimetal challenge, as compared to the effects of independent exposure to them.

Lead induced modulation of splenic macrophage responses on humoral and cell mediated immunity.

The heavy metal lead is an environmental toxic material that can induce pathophysiological changes in many organ systems. Previous studies have shown the effects of lead exposure on immune cells in different experimental animals, however, the mechanism of their influence on the immune system is unclear. We reported that in vivo lead exposure inhibits phagocytosis, nitric oxide release, induces DNA fragmentation suggesting the apoptotic death of the target cell. We have also presented evidence that inhibition of macrophage functional responses implicated alteration of humoral and cell mediated immunity. In vivo exposure to lead acetate alters the phagocytic capacity of splenic macrophages as evident from the reduction of phagocytic index of control from 19,792+/-1385.69 to 8893+/-893 in the treated group. The amount of nitric oxide released by the control cell 2.25+/-0.125 microM is also reduced to 1.9375+/-0.0625 microM upon in vivo lead treatment. Functional integrity of the target cell is also decreased after lead exposure as obtained from the percentage of DNA fragmentation. Control group shows 33.29+/-0.11% of fragmented DNA, which is enhanced to 42.43+/-0.725% following the lead treatment. A greater percentage of DNA fragmentation upon lead treatment probably indicating that the heavy metal induces apoptosis. The humoral immune response is also altered after lead exposure as indicated by the decrease of the antibody titre in control group from 1:2048 to 1:128 in the treated group. From the DTH reaction, it was observed that the mean diameter of swollen foot pad of control mice is 0.329+/-0.15 cm and that of lead treated mice is 0.274+/-0.056 cm. It can, therefore, be suggested that lead inhibits normal functional activities of splenic leukocytes, particularly phagocytosis and also affects the functional integrity of cells by inducing DNA fragmentation. The study may demonstrate the usefulness of investigation of humoral immune system and leukocyte functions as sensitive parameters in detecting the effects of lead toxicity.

Mode of inheritance of finger dermatoglyphic traits among Vaidyas of West Bengal, India.

BACKGROUND: It is well established that dermatoglyphics are genetically determined. But, to date, few studies have given attention to the inheritance pattern of dermatoglyphics. Furthermore, despite the existence of different advanced statistical packages, none of these previous studies implemented a model-fitting technique to reveal the mode of inheritance. Thus, the genetic nature of dermatoglyphics is still not clear. AIM: In the present communication, an attempt has been made to provide some information regarding the genetics of finger dermatoglyphics by estimating the magnitude and mode of inheritance of these traits. SUBJECTS AND METHODS: The fingerprints of 824 individuals from 200 families including two generations were collected from Barasat in North 24-Parganas, West Bengal. The study includes familial correlations between first-degree relatives and corresponding heritabilities. In the final stage, segregation analyses by the Pedigree Analysis Package (PAP) were conducted on these data to understand the mode of inheritance. RESULTS: The major findings indicated the following: (a) Familial correlations in all possible relationships (except spouse correlation) were statistically significant and of comparable magnitude. (b) The corresponding heritabilities were in the range between 59% for Pattern Intensity Index (PII) and 77% for Total Finger Ridge Count (TFRC). These estimates were in agreement with previously published data on this subject. (c) By segregation analysis, the 'Sporadic', 'Environmental', 'No major gene effect' as well as 'No polygenic component' models were strongly rejected (p < 0.05) and the hypothesis of a major gene's (MG) influence on all studied traits was accepted, though the proportion of MG variance was low. (d) The Most Parsimonious Mendelian model clearly indicated the contribution of a major gene with dominant (for PII) and additive (for two ridge counts) effects. CONCLUSION: The present report supports the evidence of the existence of a major gene on these dermatoglyphic traits and the transmission of this effect is consistent with Mendelian expectation.