A review on control and abatement of soil pollution by heavy metals: Emphasis on artificial intelligence in recovery of contaminated soil

"Save Soil Save Earth" is not just a catchphrase; it is a necessity to protect soil ecosystem from the unwanted and unregulated level of xenobiotic contamination. Numerous challenges such as type, lifespan, nature of pollutants and high cost of treatment has been associated with the treatment or remediation of contaminated soil, whether it be either on-site or off-site. Due to the food chain, the health of non-target soil species as well as human health were impacted by soil contaminants, both organic and inorganic. In this review, the use of microbial omics approaches and artificial intelligence or machine learning has been comprehensively explored with recent advancements in order to identify the sources, characterize, quantify, and mitigate soil pollutants from the environment for increased sustainability. This will generate novel insights into methods for soil remediation that will reduce the time and expense of soil treatment.

A review on the effect of micro- and nano-plastics pollution on the emergence of antimicrobial resistance

The recent upsurge in the studies on micro/nano plastics and antimicrobial resistance genes has proven their deleterious effects on the environmental and human health. Till-date, there is a scarcity of studies on the interactions of these two factors and their combined influence. The interaction of microplastics has led to the formation of new plastics namely plastiglomerates, pyroplastics. and anthropoquinas. It has long been ignored that the occurrence of microplastics has become a breeding ground for the emergence of antimicrobial resistance genes. Evidently microplastics are also associated with the occurrence of other pollutants such as polyaromatic hydrocarbons and pesticides. The increased use of antibiotics (after Covid breakout) has further elevated the detrimental effects on human health. Therefore, this study highlights the relation of microplastics with antibiotic resistance generation. The factors such as uncontrolled use of antibiotics and negligent plastic consumption has been evaluated. Furthermore, the future research prospective was provided that can be helpful in correctly identifying the seriousness of the environmental occurrence of these pollutants.

Production of biopolymers from food waste: Constrains and perspectives

Food is an essential commodity for the survival of any form of life on earth. Yet generation of plethora of food waste has significantly elevated the global concern for food scarcity, human and environment deterioration. Also, increasing use of polymers derived from petroleum hydrocarbons has elevated the concerns towards the depletion of this non-renewable resource. In this review, the use of waste food for the production of bio-polymers and their associated challenges has been thoroughly investigated using scientometric analysis. Various categories of food waste including fruit, vegetable, and oily waste can be employed for the production of different biopolymers including polyhydroxyalkanoates, starch, cellulose, collagen and others. The advances in the production of biopolymers through chemical, microbial or enzymatic process that increases the acceptability of these biopolymers has been reviewed. The comprehensive compiled information may assist researchers for addressing and solving the issues pertaining to food wastage and fossil fuel depletion.

Sustainable strategies for combating hydrocarbon pollution: Special emphasis on mobil oil bioremediation

The global rise in industrialization and vehicularization has led to the increasing trend in the use of different crude oil types. Among these mobil oil has major application in automobiles and different machines. The combustion of mobil oil renders a non-usable form that ultimately enters the environment thereby causing problems to environmental health. The aliphatic and aromatic hydrocarbon fraction of mobil oil has serious human and environmental health hazards. These components upon interaction with soil affect its fertility and microbial diversity. The recent advancement in the omics approach viz. metagenomics, metatranscriptomics and metaproteomics has led to increased efficiency for the use of microbial based remediation strategy. Additionally, the use of biosurfactants further aids in increasing the bioavailability and thus biodegradation of crude oil constituents. The combination of more than one approach could serve as an effective tool for efficient reduction of oil contamination from diverse ecosystems. To the best of our knowledge only a few publications on mobil oil have been published in the last decade. This systematic review could be extremely useful in designing a micro-bioremediation strategy for aquatic and terrestrial ecosystems contaminated with mobil oil or petroleum hydrocarbons that is both efficient and feasible. The state-of-art information and future research directions have been discussed to address the issue efficiently.

Hydroxychloroquine in COVID-19: therapeutic promises, current status, and environmental implications

The outbreak of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected the entire world with its infectious spread and mortality rate. The severe cases of coronavirus disease 2019 (COVID-19) are characterized by hypoxia and acute respiratory distress syndrome. In the absence of any specific treatment, just the preventive and supportive care options are available. Therefore, much focus is given to assess the available therapeutic options not only to avoid acute respiratory failure and hypoxia but also to reduce the viral load to control the severity of the disease. The antimalarial drug hydroxychloroquine (HCQ) is among the much-discussed drugs for the treatment and management of COVID-19 patients. This article reviews the therapeutic potential of HCQ in the treatment of COVID-19 based on the available in vitro and clinical evidence, current status of registered HCQ-based clinical trials investigating therapeutic options for COVID-19, and environmental implications of HCQ.

Available Compounds With Therapeutic Potential Against COVID-19: Antimicrobial Therapies, Supportive Care, and Probable Vaccines

The recent outbreak of the COVID-2019 (coronavirus disease 2019) due to the infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has realized the requirement of alternative therapeutics to mitigate and alleviate this lethal infection. These alternative therapies are effective when they are started at the initial stage of the infection. Some drugs that were used in previous other related infections SARS-CoV-2003 and Middle East respiratory syndrome coronavirus (MERS-CoV)-2012 could be potentially active against currently emerging SARS-CoV-2. This fact imparts some rationale of current interventions, in the absence of any specific therapeutics for SARS-CoV-2. It is imperative to focus on the available antimicrobial and adjunct therapies during the current emergency state and overcome the challenges associated with the absence of robust controlled studies. There is no established set of drugs to manage SARS-CoV-2 infected patients. However, closely following patients’ conditions and responding with the dosage guidelines of available drugs may significantly impact our ability to slow down the infection. Of note, it depends upon the condition of the patients and associated comorbid; therefore, the health workers need to choose the drug combinations judiciously until COVID-19 specific drug or vaccine is developed with the collective scientific rigor. In this article, we reviewed the available antimicrobial drug, supportive therapies, and probable high importance vaccines for the COVID-19 treatment.

Rhamnolipids from Planococcus spp. and their mechanism of action against pathogenic bacteria

Two bacterial species with the ability to produce biosurfactants were isolated from a pesticide contaminated soil and identified as Planococcus rifietoensis IITR53 and Planococcus halotolerans IITR55. Formation of froth indicating the surfactant production was observed when grown in basal salt medium containing 2% glucose. The culture supernatant after 72 h showed reduction in surface tension from 72 N/m to 46 and 42 N/m for strain IITR53 and IITR55 with emulsification index of 51 and 54% respectively. The biosurfactant identified as rhamnolipid based on liquid chromatography-mass spectrometry analysis, was found to inhibit the growth of both gram- positive and negative pathogenic bacteria. Both the rhamnolipids at 40 mg/mL exhibited the release of extracellular DNA and protein content. Also at one third of the MIC, a significant generation of reactive oxygen species was recorded. These rhamnolipids effectively emulsified different vegetable oils suggesting their possible utilization as antimicrobial agent.

Biosynthesis and characterization of sophorolipid biosurfactant by Candida spp.: Application as food emulsifier and antibacterial agent

Biosurfactants from the yeast strains Candida albicans SC5314 and Candida glabrata CBS138 were isolated and characterized. Surface tension of the cell-free broth was reduced from 72 N/m to 42 N/m and 55 N/m respectively. The biosurfactants showed emulsifying ability as the indices against castor oil were determined to be 51% and 53% for C. albicans and C. glabrata respectively and were found stable between pH 2 and 10, temperature 4-120 °C and salt concentration 2-14%. The partially purified surfactants were identified as sophorolipid using Fourier transform infrared spectroscopy. Isolated sophorolipid showed antibacterial properties against pathogenic bacteria and generated reactive oxygen species in Bacillus subtilis and Escherichia coli. Flow cytometric analysis revealed that 60 mg/L of C. glabrata biosurfactant killed 65.8% B. subtilis and 4% E. coli. The data here obtained indicates applications of biosurfactant focusing mainly as antimicrobial and therapeutic perspectives.

Rhamnolipid from a Lysinibacillus sphaericus strain IITR51 and its potential application for dissolution of hydrophobic pesticides

Rhamnolipid produced from a Lysinibacillus sphaericus IITR51 was characterized and its ability for dissolution of hydrophobic pesticides were evaluated. L. sphaericus produced 1.6 g/L of an anionic biosurfactant that reduced surface tension from 72 N/m to 52 N/m with 48% emulsification index. The biosurfactant was found stable over a wide range of pH (4.0-10.0), temperature (4-100 °C), salt concentration (2-14%) and was identified as rhamnolipid. At the concentration of 90 mg/L rhamnolipid showed enhanced dissolution of α-, β-endosulfan, and γ-hexachlorocyclohexane up to 7.2, 2.9, and 1.8 folds, respectively. The bacterium utilized benzoic acid, chlorobenzene, 3- and 4-chlorobenzoic acid as sole source of carbon and was found resistant to arsenic, lead and cadmium. Furthermore, the isolated biosurfactant showed antimicrobial activities against different pathogenic bacteria. The results obtained indicate the usefulness of rhamnolipid for enhanced dissolution and thereby increasing the bioavailability.

Proton NMR metabolic profiling of CSF reveals distinct differentiation of meningitis from negative controls

BACKGROUND

Cerebrospinal fluid (CSF) is an essential bio-fluid of the central nervous system (CNS), playing a vital role in the protection of CNS and performing neuronal function regulation. The chemical composition of CSF varies during onset of meningitis, neurodegenerative disorders (positive controls) and in traumatic cases (negative controls).

METHODS

The study design was broadly categorized into meningitis cases, negative controls and positive controls. Further differentiation among the three groups was carried out using Principal Component Analysis (PCA) followed by supervised Partial Least Square Discriminant Analysis (PLS-DA).

RESULTS

The statistical analysis of meningitis vs. negative controls using PLS-DA model resulted in R² of 0.97 and Q² of 0.85. There was elevation in the levels of ketone bodies, total free amino acids, glutamine, creatine, citrate and choline containing compounds (choline and GPC) in meningitis cases. Similarly, meningitis vs. positive controls resulted in R² of 0.80 and Q² of 0.60 and showed elevation in the levels of total free amino acids, glutamine, creatine/creatinine and citrate in the meningitis group. Four cases of HIV were identified by PLS-DA model as well as by clinical investigations.

CONCLUSION

On the basis of metabolic profile it was found that negative control CSF samples are more appropriate for differentiation of meningitis than positive control CSF samples.

Toll-like receptors TLR4 (Asp299Gly and Thr399Ile) and TLR2 (Arg677Trp and Arg753Gln) gene polymorphisms in end-stage renal disease patients on peritoneal dialysis

BACKGROUND

Toll-like receptors (TLRs), expressed on cells of the innate immune system, are the first line of host defense. Recognition of bacterial pathogens by the peritoneum is mediated in part by TLR. In this study, we investigated the role of TLR4 (Asp299Gly and Thr399Ile) and TLR2 (Arg677Trp and Arg753Gln) gene polymorphisms in end-stage renal disease (ESRD) patients on peritoneal dialysis (PD).

METHOD

A total of 100 ESRD patients on PD and 150 healthy controls were enrolled in the study. The patients were divided into two groups: ESRD patients on PD with peritonitis (n = 38) and without peritonitis (n = 62). Genotyping of TLR4 (Asp299Gly and Thr399Ile) and TLR2 (Arg677Trp and Arg753Gln) genes were performed by polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP).

RESULTS

Heterozygous variant of TLR4 (Thr399Ile) Thr/Ile genotype showed significant association with both groups of patients (patients with and without peritonitis) with no difference between the groups. Overall, TLR4 (Thr399Ile) Thr/Ile genotype demonstrated an association with ESRD on PD (OR 3.9). Further, TLR4 (Thr399Ile) polymorphism showed significant association with PD patients having two or more episodes of peritonitis compared to patients with no peritonitis. No such association of increased risk of ESRD was observed with TLR4 (Asp299Gly) Asp/Gly genotype and TLR2 polymorphisms. Haplotype frequencies, Gly/Ile and Asp/Ile, conferred 2.46- and 4.62-fold increased risk of ESRD, respectively.

CONCLUSIONS

TLR4 Thr399Ile genotype was associated with ESRD patients on PD; however, the genotype frequency was similar in PD patients with and without peritonitis.

Increasing Trend of Heterogeneous Vancomycin Intermediate Staphylococcus aureus in a Tertiary Care Center of Northern India

Heterogeneous vancomycin intermediate Staphylococcus aureus (hVISA) strains are increasingly reported, and their association with vancomycin treatment failure is a well-known problem worldwide. A total of 500 clinical isolates of methicillin-resistant S. aureus were screened for hVISA by four different methods from May 2011 to May 2014. The number of strains screened for hVISA from May to April in 2011-2012, 2012-2013, and 2013-2014 were 198, 123, and 179, respectively. hVISA strains were studied by transmission electron microscopy (TEM) for cell wall thickness and also for their ability to form biofilm on a polystyrene microtiter plate. hVISA strains detected by four different methods-brain heart infusion agar with vancomycin with 4 mg/L/gradient plate/macro E-test/and glycopeptide resistance detection (GRD) E test-were as follows: 11.6%/10%/9%, and 9.5% in 2011-2012, 12.1%/9.7%/8.9%, and 10.5% in 2012-2013, and 13.9%/11.7%/11.1%, and 12.8% in 2013-2014, respectively. Population analysis profile-area under curve analysis confirmed hVISA in 4.5% (9/198), 6.5% (8/123), and 6.7% (12/179) in respective years; 24% (7/29) of hVISA isolates were nonsusceptible to daptomycin. TEM showed a significant increase in cell wall thickness of hVISA isolates (p<0.001) with a distinct reduction in their biofilm formation ability.

Experimental determination of carbon dioxide evolution during aerobic composting of agro-wastes

This work aims at optimal composting of agro-wastes like sugarcane bagasse, wood straw and soya husk. A mixture of these substances along with small quantity of food waste as the seed was composted aerobically and carbon dioxide evolved was determined experimentally using a composting system comprising aerobic digester, operating in near-optimal conditions with regard to adequacy of oxygen and temperature in the system. During aerobic composting of agro-waste carbon dioxide is produced due to degradation of different carbon fractions in the substrate. Carbon dioxide production rate, which is a measure of bacterial/fungal activity in composting systems, can be related to various process parameters like different carbon fractions present in the substrate and their reaction rates, progress and termination of compost phenomenon and stabilization of organic matter. This gives a balanced compromise between complexity of mathematical model and extensive experimentation, and can be used for determining optimum conditions for composting.

Isolation of integral membrane proteins of Leishmania promastigotes and evaluation of their prophylactic potential in hamsters against experimental visceral leishmaniasis

The integral membrane proteins (IMP's) of promastigotes of two virulent strain of Leishmania (L.) donovani Dd8 and Leishmania (L.) infantum LV9 and one avirulent viscerotropic strain Leishmania tropica UR6 were extracted by phase separation technique using a non-ionic detergent "Triton X-114". This detergent is homogeneous at 0 degrees C but divides in an aqueous phase and a detergent phase at above 20 degrees C. The phase partition resulted in solubilisation of hydrophilic proteins in aqueous phase, and IMP's with an amphiphilic nature were recovered in the detergent phase. The strain wise quantitative recovery rates of IMP's were estimated. These proteins were purified by chill methanol centrifugation and used as vaccinogen, alone or in combination with adjuvant against L. donovani challenge in hamster model. Among all the combinations, hamsters immunised with IMP of L. donovani (Dd8) in combination with CFA resulted in 75% parasite inhibition in spleen (P <0.001), however, 61.14% (P <0.001) and 77.60% (P <0.001) parasitic inhibition was achieved in liver and bone marrow respectively as compared to their unvaccinated counter part. Similar combinations with UR6 and LV9 strain inhibited the parasite establishment up to 65.12% (P <0.001) and 66.87% (P <0.001), respectively on splenic site. The specific IgG level against (Dd8 strain) soluble leishmania promastigote antigen was monitored at different stages by enzyme linked immunosorbent assay (ELISA) corresponds to the level of parasitic establishment. Similar observations were made in cases of LV9 and UR6 strains. However, significant lymphoproliferative response to IMPs of Dd8 strain (SI 3.5-4.9, P <0.001) was noticed in all IMP + CFA vaccinated animals. Thus, this study will provide a lead for more manipulative trials to develop a subunit vaccine against the fatal disease.

Heterogeneity in proliferative potential of ovine mesenchymal stem cell colonies

Bone marrow biopsies were taken from the iliac crest of 28 individual sheep from three different breeds, ranging in age from 4 months to 8 years and mesenchymal stem cells (MSCs) isolated using selection due to plastic adherence. Cells were cultured in medium that had been selected for its effect on observed MSC proliferation, until populations of greater than 50 million had been obtained from each biopsy. The identity of the isolated cell populations as progenitors of the mesenchymal lineage was verified by deriving both osteoblastic and chondrocytic phenotypes when cultured in osteogenic and chondrogenic medium supplements, respectively. The rate of cell proliferation for each marrow biopsy was measured at each passage and the number of initial stem cells in each sample estimated. There was no statistically significant correlation between the age of the sheep and MSC proliferative potential, or age and estimated initial MSC number. There was no apparent significant difference between proliferation rate and sheep breed and colonies established from frozen cells grew at similar rates to pre-frozen cells. Counter intuitively, there appeared to be a negatively correlated trend between proliferation rate and MSC concentration in the samples. It is concluded that no initial descriptive statistics of the marrow biopsies can assist in estimating the proliferative potential, and therefore the timing of future surgeries, of MSCs sampled for the purposes of tissue engineering.

Metabolic and histological analysis of mesenchymal stem cells grown in 3-D hyaluronan-based scaffolds

Sheep mesenchymal stem cells (MSCs) were isolated and expanded using the principle of plastic adherence. Their identity as progenitor cells was confirmed by induction along the osteoblastic lineage using osteogenic supplements and observation of calcific deposits by von Kossa staining. MSCs were seeded onto two types of hyaluronan-based cylindrical scaffolds in high concentrations and cultured for varying time points up to three weeks. Culture medium was supplied using the following conditions: statically, on a shaker, by stirring with a magnetic stirrer or by perfusion in a tubular flow circuit. Total cell metabolism was assessed by MTT assay and the quality of cell coverage and matrix formation observed by SEM and histological analysis of thin sections of the constructs. Perfusion culture was established as the most appropriate culturing conditions, with cell metabolism increasing by approximately 300% over three weeks. The coverage of the scaffold surface was very good and the deposition of collagenous matrix was superior in these conditions compared to the, static and other dynamic culture conditions.

Prophylactic potential of autoclaved Leishmania donovani with BCG against experimental visceral leishmaniasis

The prophylactic efficacy of autoclaved Leishmania donovani (ALD) and autoclaved L. major (ALM)--a heterologous vaccine developed against cutaneous leishmaniasis (used as a reference vaccine), along with BCG--was evaluated against L. donovani in hamsters (Mesocricetus auratus). Animals were immunized with triple doses (21 days apart) of either ALD or ALM (1.0 mg) with or without BCG (0.1 mg) and challenged 21 days later with 1 x 10(6) L. donovani amastigotes intracardially. Animals immunized with ALM + BCG and ALD + BCG yielded 94.3% and 86.1% parasite inhibition respectively in comparison to the BCG only and unvaccinated controls. Fifty and 33.3% of the vaccinated animals (ALM + BCG and ALD + BCG respectively) were completely devoid of parasites when tested on day 45 post-challenge (p.c.) and survived till the experiment was terminated. The mean survival of ALM + BCG and ALD + BCG groups (animals harbouring parasites) was longest (168 and 139 days respectively). No significant increase in anti-leishmanial antibody level (ELISA) was noticed in ALD + BCG and ALM + BCG groups whereas it increased progressively in the rest of the experimental groups. The lymphoproliferative responses to PHA and Con A, of the 2 vaccinated groups were comparable to that of normal controls on day 45 p.c. The study suggests that ALD along with BCG can offer substantial protection against visceral leishmaniasis in hamsters.

Establishment of asymptomatic Leishmania donovani infection in Indian langurs (Presbytis entellus) through intradermal route

Indian langurs, which were previously reported to be highly susceptible, were infected intradermally using variable numbers of promastigotes along with different doses, 1/2 pair, 5 pairs and 10 pairs respectively of salivary gland lysate (SGL). Although, all the monkeys developed mild infection and remained subclinically infected throughout the observation period, which later resolved, none of them could develop the classical disease. No marked antigen specific antibody or lymphoproliferative response was noticed throughout the experimental period. However, a late IFN-gamma response (by day 90 pi.) was demonstrated in monkeys infected with 2 x 10(6) promastigotes +10 pairs SGL. It seems that a single intradermal dose of promastigotes with or without SGLs had a vaccines like effect. Perhaps, multiple frequent inoculations, as happens in the natural situation, may be necessary for the development of full-blown disease.

Successful vaccination against Leishmania donovani infection in Indian langur using alum-precipitated autoclaved Leishmania major with BCG

Autoclaved Leishmania major (ALM) along with BCG, presently undergoing phase II clinical trial by WHO for its vaccine potential against cutaneous leishmaniasis, has been successfully evaluated in single and triple dose schedules against L. donovani in Indian langurs (Presbytis entellus). Encouraged with the results, another formulation alum-precipitated ALM (provided by WHO) along with BCG has been evaluated in this system. Eight monkeys were vaccinated with alum-precipitated ALM + BCG (1 mg of each per animal) while four were kept as unvaccinated controls. All were challenged with 100 x 10(6) amastigotes i.v. on day 60 post vaccination. Parasitic assessment in splenic tissue was performed on day 45, 90 and 180 p.c. Initially, seven of the eight vaccinated monkeys developed infection (two to six amastigotes per 1000 cell nuclei), which resolved by day 180 p.c., while the eighth monkey had a parasite burden of 14 amastigotes per 1000 cell nuclei on day 45 p.c. and died on day 130 p.c. On the other hand, there was progressive infection in unvaccinated control animals and three out of four died between days 110 and 120 p.c., and one monkey, which had low parasite burden, died on day 178 p.c. Prior to challenge, there was an initial rise in antileishmanaial antibodies in the vaccinated group compared to the unvaccinated control group, which later came down to normal level, while it remained higher in the unvaccinated control group. An increasing pattern of antigen-specific proliferative responses and interferon-gamma level to the two antigens--autoclaved L. donovani (ALD) and ALM--was observed in vaccinated monkeys throughout the experiment. There was a good correlation between parasite burden and IFN-gamma level on days 90 and 180 p.c., indicating IFN-gamma response as a sensitive parameter of immune status. The findings suggest alum-precipitated ALM+BCG as a potential vaccine against visceral leishmaniasis and warrants clinical trials.

Leishmania donovani: cellular and humoral immune responses in Indian langur monkeys, Presbytis entellus

We have previously reported that disease mimicking human visceral leishmaniasis can be established in Presbytis entellus, the Indian langur monkey, following a single intravenous challenge of 10(8) Leishmania donovani amastigotes. In the present report, infection was assessed in monkeys infected intravenously with a single dose of 10(8) amastigotes (HDA group), three weekly doses of 10(7) amastigotes (LDA group) and three weekly doses of 5 x 10(7) promastigotes (HDP group). Typical clinical infection was established in all three groups with significant parasite load. There was a gradual and sustained rise in anti-leishmania specific immunoglobulin G response, and a severe fall in the lymphoproliferative response to the T cell mitogens PHA and Con A by day 80 post infection (p.i.). The antibody level remained elevated until death in monkeys of the HDA and HDP groups; the T-cell responses showed a recovery prior to death. T-cell responses to leishmania antigen, however, could not be demonstrated in any of these monkeys prior to death. One monkey of the LDA group survived for 155 days and two monkeys spontaneously eradicated the infection. Surprisingly, one monkey of the HDA group also achieved spontaneous cure. In the three monkeys which eradicated infection spontaneously, the antibody level declined to baseline levels on day 180 p.i. with a well demonstrable antigen specific lymphoproliferative response; no parasites could be demonstrated in splenic aspirates by direct examination of culture. These data demonstrate that disease severity may be the function of the total inoculum dose rather than the stage of the parasite and that the immunological responses in the Indian langur model parallel the reported changes in human visceral leishmaniasis. This makes the langur a potentially useful model for the evaluation of candidate anti-leishmanial drugs and vaccines.

Vaccination of langur monkeys (Presbytis entellus) against Leishmania donovani with autoclaved L. major plus BCG

The protective potential of killed Leishmania major (ALM) along with BCG was evaluated against L. donovani in Indian langur monkeys in single and triple dose schedules. A delayed protection was observed in monkeys after a single dose schedule of ALM (3 mg)+BCG (3 mg) given intradermally 2 months before intravenous challenge with L. donovani. Triple dose schedule each of 1 mg ALM + 1 mg BCG was more effective. The status remained unchanged until the end of the experiment (approximately 8 months). The study indicates that a combination of ALM + BCG may be a good candidate vaccine for exploiting against human Kala-azar.

Metabolic disposition of methyl [5-[[4-(2-pyridinyl)-1-piperazinyl] carbonyl]-1-H-benzimidazol-2-yl] carbamate in hamsters: a study to understand chemoprophylactic action against experimental Ancylostomiasis

Methyl [5-[[4-(2-pyridinyl-1-piperazinyl] carbonyl]-1H- benzimidazol-2-yl] carbamate (CDRI Compound 81-470) exhibits a long prophylactic action against experimental ancylostomiasis, when given parenterally but not orally. To find out an explanation for such a behaviour, metabolic disposition studies were performed in hamsters using [3H] compound 81-470. Following intramuscular administration, the compound was found to form a depot at the site of injection and to remain there in substantial amount for more than 7 weeks. The compound was fairly distributed in all the organs studied and the presence of radioactivity could be easily detected up to 7 weeks of observation period. The compound was very slowly eliminated from the body and only 38% of the radioactivity could be recovered in the urine and faeces during 14 days. The oral dose, to the contrary, was poorly absorbed and more than 62.8% was excreted in the faeces within 48 hr. Consequently, this dose yielded lesser area under plasma curve. More than 95% of the oral dose was eliminated within a week and hardly and radioactivity could be detected in the tissues after day 14. In accord with this pattern, in blood also the im dose was detected up to 7 weeks while the orally given compound reached undetectable level within 6 days only. The lower clearance and prolonged stay in the body of the im dose compared to quick elimination of the oral dose may be responsible for the long chemoprophylactic action of compound 81-470 when given through im route.

Role of reactive oxygen species in the chemoprophylactic action of methyl [5-[[4-(2-pyridinyl)-1-piperazinyl]-carbonyl]-1H-benzimidazol-2 yl] carbamate in hamster against Ancylostoma ceylanicum

To delineate mechanisms involved in the prophylactic action of methyl [5-[[4-(2-pyridinyl)-1-piperazinyl]-carbonyl]-1H-benzimidazol-2 yl] carbamate (compound 81/470) in hamster against Ancylostoma ceylanicum infection, plasma level of the compound and status of reactive oxygen metabolites in jejunum at different periods of the drug treatment were examined. The compound was found to enhance the generation of both O2- and H2O2 by the jejunum possibly by activating xanthine oxidase. This stimulation was found to be both time and dose dependent. At 100 mg/kg dose the increase in O2- production could be recorded at least upto 50 days, whereas at 25 mg/kg the stimulation remained effective upto 20 days only, and at 5 mg/kg there was no change in the activity. This correlated well with the reported prophylactic pattern of the compound i.e. upto 45 and 7 days by 100 and 25 mg/kg doses, respectively. Plasma level of the compound also exhibited dose dependent variation. The compound given at 100 mg/kg dose could be detected in significant concentration upto at least 42 days while that given in 25 and 5 mg/kg doses was present in equivalent concentration upto 14 days and 1 day, respectively. It is concluded that the activation of respiratory burst in the jejunum induced by the persistent presence of compound 81/470 may represent one of the important mechanisms for the chemoprophylactic activity of this anthelmintic.

Evaluation of enzyme-linked immunosorbent assay in the diagnosis of kala-azar in Malda district (West Bengal)

An immunological test based on indirect (plate) ELISA has been successfully standardized and modified using promastigote soluble antigen. The test carried out on 813 subjects from a kala-azar endemic area (including parasitologically confirmed patients, subjects presenting with clinical symptoms of visceral leishmaniasis and endemic controls) and a non-endemic area (with diseases other than kala-azar and apparently normal subjects) was found to detect, specifically, antileishmanial antibodies. The plate ELISA has been simplified to a more sensitive dot-ELISA where the results are read within 2-3 h. The antigen requirement is 250 ng per test. No cross-reactivity with sera from patients of malaria, tuberculosis, leprosy, amoebiasis and filariasis was observed. The follow up monitoring of antibodies in successfully treated kala-azar patients showed a decline of antibodies. A drop of blood taken on filter paper is sufficient to conduct the test. Dot ELISA therefore is a simple, inexpensive and stable test in serodiagnosis of visceral leishmaniasis.

Role of reactive oxygen species in expulsion of Nippostrongylus brasiliensis from rats

To understand the mechanism for the expulsion of Nippostrongylus brasiliensis from rats, age-dependent variations in the metabolism of reactive oxygen species in the parasite and the host intestines were examined. N. brasiliensis showed an age-dependent increase in its susceptibility to xanthine-xanthine oxidase and t-butyl hydroperoxide generated oxidants as well as to H2O2. Protection obtained with several scavengers suggested that the worms were damaged by the combined action of oxidants generated by the in vitro systems employed. The level of superoxide dismutase in the nematode and its release into the surroundings exhibited a marked depression with advancement of age. No such alteration was, however, recorded for catalase and glutathione peroxidase. An appreciable decrease in the level of reduced glutathione in older N. brasiliensis appears to render them prone to oxidant attack. The rat intestines, on the other hand, exhibited an appreciable depression in catalase and a reduced glutathione content with progress of the infection. Vitamin E levels were elevated. The release of O2-. and H2O2 by the intestines was also found to be greater during later stages of the infection. The combined effect of the changes observed in N. brasiliensis and in the rat intestines may be at least partly responsible for expulsion of the nematode from the rats after day 10.

Ancylostoma ceylanicum infection in female hamsters: an observation on altered reproductive function

Reproductive performances of female hamsters were investigated during Ancylostoma ceylanicum (hookworm) infection. Animals having the highest levels of infection (34.96 +/- 1.11 worms) showed degenerative changes in the reproductive system. Ovaries of infected animals contained a few primary or secondary follicles. On cocaging with males of proven fertility, only 7-8% (80% in controls) of the infected females mated but did not conceive as evidenced by the absence of corpora lutea or implantation sites on day 10 postcoitum. Animals with low worm burdens (5.94 +/- 0.65 worms), however, showed almost normal fertility. The uterine weight bioassay and compensatory ovarian hypertrophy suggest strong suppression of pituitary gonadotrophin contents in infected females. Resorptive effects on the pregnancy outcome of infected female hamsters were also recorded.

Effect of anthelmintics on the antioxidant system of Nippostrongylus brasiliensis

To understand the mode of anthelmintic action of thiabendazole and methyl-[5-[[4-(2-pyridinyl)-l-piperazinyl]carbonyl]-1H-benzimidazole- 2-yl] carbamate (C.D.R.I. compound 81/470) against Nippostrongylus brasiliensis, their effect on the metabolism of reactive oxygen species in the parasite as well as in rat intestine was examined. Both drugs produced a significant depression in the levels of superoxide dismutase (SOD) and reduced glutathione (GSH) of the parasite. Release of antioxidant enzymes by the drug-treated worms was also found to be appreciably lowered. Both thiabendazole and compound 81/470 induced a depression in the levels of all five constituents of the antioxidant system of rat intestine but significant alterations were detected only in the GSH content of infected and the SOD activity of normal intestine. The production of O2- by treated intestine was, on the other hand, markedly enhanced. Increased formation of O2- by the host intestine accompanied with the reduced level of SOD and GSH in N. brasiliensis appear to have a deleterious effect on the parasite. Consequently, the drug-treated worms are unable to retain themselves in situ and are ultimately expelled. The greater effect produced on these parameters by thiabendazole compared to compound 81/470 is consistent with the relative efficacy of these anthelmintics.

Efficacy of methyl 5(6)-(alpha-hydroxyphenylmethyl) benzimidazole-2-carbamate, a metabolite of mebendazole, against developing forms of experimental helminth parasites

Methyl 5(6)-(alpha-hydroxyphenylmethyl) benzimidazole-2- carbamate, a metabolite of mebendazole, was evaluated against metamorphic forms of Ancylostoma ceylanicum in hamsters, Nippostrongylus brasiliensis in rats and cysticercoids of Hymenolepis nana in grain beetles. The test compound offered better action than mebendazole except against H. nana cysticercoids where the activity of the compound and mebendazole was comparable, but was inferior to the standard cestodicidal drug, praziquantel. The results suggest that the action was better by ip route compared to per os route of drug administration.

Effects of methyl [5 [[4-(2-pyridinyl)-1-piperazinyl]carbonyl]-1H-benzimidazol-2-yl] carbamate on energy metabolism of Ancylostoma ceylanicum and Nippostrongylus brasiliensis

Effects of methyl [5[[4-(2-pyridinyl)-1-piperazinyl] carbonyl] 1H-benzimidazol-2-yl] carbamate (CDRI Comp. 81-470) and mebendazole on the energy metabolism of A. ceylanicum and N. brasiliensis were compared. At 10 and 50 microM concentration both compounds inhibited glucose uptake and its conversion into metabolic endproducts. The shift towards the increased production of lactic acid appeared to be the result of inhibition of PEP carboxykinase and increase in LDH activity. The compounds also caused significant inhibition of ATP production in mitochondria.

Ancylostoma ceylanicum: migratory behaviour in golden hamsters after oral and parenteral infection

The infectivity and migratory pattern of Ancylostoma ceylanicum infective larvae (L3) were investigated in hamsters infected by various routes. Following oral administration 40-70% of L3 attained maturity and there was no tissue migration. Following subcutaneous inoculation a small number (1-1.2%) of L3 attained maturity in the intestine after completing the broncho-oesophageal journey. Larvae which penetrated the skin also became adult in the intestine. Most of the larvae entering parenterally remained at the site of infection and in the tracheal region for more than 100 days without undergoing any development, other than desheathment. Those transmitted orally to naive hamsters developed in the normal way. Larvae inoculated parenterally into female hamsters were able to infect offspring in milk, but could not cross the placental barrier.

Postcoital pneumoperitoneum

A case of postcoital pneumoperitoneum occurring 2 months after abdominal hysterectomy is presented along with a review of the literature. The authors believe this is the first reported case of postcoital pneumoperitoneum after abdominal hysterectomy.