Evaluation of the mosquitocidal efficacy of fluralaner, a potential candidate for drug based vector control

Vector control is a key intervention against mosquito borne diseases. However, conventional methods have several limitations and alternate strategies are in urgent need. Vector control with endectocides such as ivermectin is emerging as a novel strategy. The short half-life of ivermectin is a limiting factor for its application as a mass therapy tool for vector control. Isoxazoline compounds like fluralaner, a class of veterinary acaricides with long half-life hold promise as an alternative. However, information about their mosquitocidal effect is limited. We explored the efficacy of fluralaner against laboratory reared vector mosquitoes-Aedes aegypti, Anopheles stephensi, and, Culex quinquefasciatus. 24 h post-blood feeding, fluralaner showed a significant mosquitocidal effect with LC50 values in the range of 24.04-49.82 ng/mL for the three different mosquito species tested. Effects on life history characteristics (fecundity, egg hatch success, etc.) were also observed and significant effects were noted at drug concentrations of 20, 25 and 45 ng/mL for Ae. aegypti, An. stephensi, and, Cx. quinquefasciatus respectively. At higher drug concentration of 250 ng/mL, significant mortality was observed within 1-2 h of post blood feeding. Potent mosquitocidal effect coupled with its long half-life makes fluralaner an excellent candidate for drug based vector control strategies.

A comprehensive evaluation of the longitudinal association between alcohol consumption and a measure of inflammation: Multiverse and vibration of effects analyses

BACKGROUND

Moderate alcohol consumption appears to be associated with reduced inflammation. Determining whether this association is robust to common variations in research parameters has wide-reaching implications for our understanding of disease aetiology and public health policy. We aimed to conduct comprehensive multiverse and vibration of effects analyses evaluating the associations between alcohol consumption and a measure of inflammation.

METHODS

A secondary analysis of the 1970 British Birth Cohort Study was performed, using data from 1970 through 2016. Measurements of alcohol consumption were taken in early/mid-adulthood (ages 34 and 42), and level of inflammation marker high-sensitivity C-reactive protein (hsCRP) at age 46. Multiverse analyses were applied to comparisons of low-to-moderate consumption and consumption above various international drinking guidelines with an 'abstinent' reference. Research parameters of interest related to: definitions of drinking and reference groups; alcohol consumption measurement year; outcome variable transformation; and breadth of covariate adjustment. After identifying various analytic options within these parameters and running the analysis over each unique option combination, specification curve plots, volcano plots, effect ranges, and variance decomposition metrics were used to assess consistency of results.

RESULTS

A total of 3101 individuals were included in the final analyses, with primary analyses limited to those where occasional consumers served as reference. All combinations of research specifications resulted in lower levels of inflammation amongst low-to-moderate consumers compared to occasional consumers (1st percentile effect: -0.21; 99th percentile effect: -0.04). Estimates comparing above-guidelines drinking with occasional consumers were less definitive (1st percentile effect: -0.26; 99th percentile effect: 0.43).

CONCLUSIONS

The association between low-to-moderate drinking and lower hsCRP levels is largely robust to common variations in researcher-defined parameters, warranting further research to establish whether this relationship is causal. The association between above-guidelines drinking and hsCRP levels is less definitive.

Design, synthesis, characterization and insecticidal screening of novel anthranilic diamides comprising acyl thiourea substructure

BACKGROUND

Mosquito-borne pathogens constitute a major health problem worldwide. The extermination of the mosquito remains a significant issue in public health. Chemical insecticides have been used to control mosquitoes for decades. However, resistance has become a limiting factor for their control. The anthranilic diamide insecticides possess excellent insecticidal activities against Lepidoptera and its resistant strains by draining internal calcium stores on activating insect ryanodine receptors. However, the reports on the effect on mosquitoes are scarce and hence a series of novel anthranilic diamides comprising acyl thiourea substructure were synthesized and their insecticidal activities against three vector mosquito larvae namely, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi were evaluated as per WHO protocol. Also investigated the morphological observations of treated larvae.

RESULTS

Novel anthranilic diamides containing an acyl thiourea substructure were synthesized and structures were established by ¹ H nuclear magnetic resonance (NMR), ¹³ C NMR, Fourier transform infrared (FTIR) and high-resolution mass spectrometry (HR-MS). Mosquito larvicidal activity of the title compounds 6-a-s revealed that compound 6-l exhibited marked larvicidal activities against C. quinquefasciatus and A. aegypti 3rd instar larvae with median lethal concentrations (LC₅₀ ) values of 0.0044 mm and 0.0070 mm, respectively, for 48 hours of treatment. Compound 6-g exhibited larvicidal activity against An. stephensi with LC₅₀ value of 0.0085 mm. Peculiar morphological alterations in the body of the treated larvae leading to death were observed on microscopic examination.

CONCLUSION

Novel anthranilic diamides containing an acyl thiourea substructure were designed, synthesized and characterized. Their bioassay results demonstrated significant mosquito larvicidal activity with striking morphological alterations in the body, which should ensure forthcoming designs of highly active diamide derivatives as mosquito larvicides. © 2022 Society of Chemical Industry.

Design, synthesis, and in vitro evaluation of thiosemicarbazone derivatives as anti-filarial agents

Effective macrofilaricidal drugs are not commercially available, and in an endeavour to find out new macrofilaricidal agents, in this research work, thiosemicarbazone derivatives have been prepared and tested against adult Setaria digitata, a cattle filarial parasite, as a model nematode for the filarial parasite, Wuchereria bancrofti. Lipinski and Veber rules have been used to design these molecules and found out that all the designed molecules show drug-like molecular properties. The in vitro anti-filarial potential of thiosemicarbazones against S. digitata was carried out using worm motility and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) reduction colorimetric assays at 100 μg/ml concentration for the incubation period of 24 h. The standard drugs used at present for filaria, Albendazole, Ivermectin and Diethylcarbamazine were not able to kill the adult filarial worms effectively. In contrast, phenyl thiosemicarbazones with trifluoromethyl substitution at 3rd and 4th positions, 2-pyrrolyl, and isatinyl made the adult worms immotile and also showed 69%-83% inhibition in formazan formation an indicator of non viability.

TB related stigma and gender disparity among unaffected population in central Kerala, a survey

BACKGROUND

TB continues to ravage high burden countries despite aggressive TB control measures. Poverty and adverse socioeconomic and cultural factors play a significant role in stigmatization, causing delayed health care seeking, non-compliance to treatment and spread of disease in the community. Women are more vulnerable to stigmatization, posing the risk of gender inequality in health care. The objectives of this study were to ascertain the degree of stigmatization and gender disparity in TB related stigma in the community.

METHODS

Study was conducted among TB unaffected persons, using consecutive sampling from bystanders of patients attending the hospital for diseases other than TB. Closed structured questionnaire was used for measuring socio-demographic, knowledge and stigma variables. Stigma scoring was done using TB vignette.

RESULTS

Majority subjects (119 males and 102 females) were from rural area and low socioeconomic status; more than 60% of males and females having college education. Half the subjects answered more than half the TB knowledge questions correctly. Knowledge score was significantly lower among females compared with males (p < 0.002) despite high literacy. Overall stigma scoring was low (mean score = 15.9; total 75). Stigma was higher among females compared with males (p < 0.002); more profound among females receiving female vignettes (Chi-square = 14.1, p < 0.0001). The association was significant even after adjusting for co-variables (OR = 3.323, P = 0.005). Low knowledge showed minimal (statistically insignificant) association with stigma.

CONCLUSIONS

Perceived stigma though low, was more among females and much higher with female vignette, indicating significant gender disparity in stigma towards TB.

Attitudes to driving among patients with diabetes mellitus in Punjab (ADD-Punjab study)

AIM

Currently there are no regulations regarding diabetes and driving licensing in India. The study was planned to gather information about attitudes to driving among patients with diabetes mellitus.

METHODS

Adult patients with diabetes mellitus holding a current valid driving license on treatment with insulin or secretagogue were interviewed using a validated structured questionnaire.

RESULTS

150 patients were interviewed with a mean age of 52 years, males (86%), insulin users (34%) and only secretagogue users (66%). 16 (10.6%) patients had severe hypoglycemia in the past year with 9.3% having hypoglycemic unawareness. Only 32% patients were aware of the relation between hypoglycemia and driving, 88.6% never checked glucose prior to driving and only 23% patients carried carbohydrates for treatment of hypoglycemia during driving. 25 (16.7%) of subjects had hypoglycemia during driving and in 6 (4%) this involved a traffic accident in the past one year.

CONCLUSIONS

Around 4% of patients on hypoglycemia causing treatment have a traffic accident/event every year. In the absence of regulations currently, focus should be on patient education. However, on the long-term appropriate regulations will make the roads safer for patients with diabetes.

Risk and protective factors for opioid overdose during the COVID-19 pandemic

Introduction

People who use drugs (PWUD) are now at the intersection of two public health emergencies – the Covid-19 pandemic and the overdose crisis. They may be at heightened risk of overdose due to increased isolation, worsened mental health, and changes to the illicit drug supply. The province of British Columbia (BC) in Canada is anticipated to experience a record-breaking year of overdose deaths as over 1,500 people (32.9 deaths per 100,000) have died from overdose in 2020. In response, BC released new clinical guidelines in March to allow the prescribing of pharmaceutical alternatives aiming to reduce PWUD’s risk of overdose and contracting Covid-19.

Objectives

We examined the risk and protective factors for overdose during these dual crises. We explored how the Covid-19 pandemic has impacted the mental health and substance use of PWUD and their access to treatment and harm reduction services.

Methods

We are conducting a survey among patients with opioid use disorder at a major hospital in Vancouver, BC. It includes the following domains: sociodemographic characteristics; mental and physical health; substance use patterns; opioid overdose history; access to treatment, harm reduction services; impacts of Covid-19.

Results

We anticipate collecting data from 200 participants. Descriptive statistics and regression analysis will be conducted to describe the sample and determine the risk, protective factors for overdose.

Conclusions

We will gain a better understanding of overdose risk in PWUD who are now navigating the complex challenges created by the dual crises. This will in turn inform the establishment of evidence-based strategies to reduce their overdose risk.

Disclosure

No significant relationships.

Cosmetic and Functional Outcomes of Septorhinoplasty

To find out the improvement in cosmetic and functional aspects as measured using Rhinoplasty outcome evaluation questionnaire following Septorhinoplasty. To measure the increase in nasal airflow as measured using "Peak Nasal Inspiratory Flow meter" in patients undergoing Septorhinoplasty.

DESIGN

prospective cohort study.

SETTINGS

patients with complaints of nasal obstruction and external deformity who are undergoing Septorhinoplasty after evaluation.

SUBJECTS

patients undergoing Septorhinoplasty at Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla during a period of 1½ years, starting from 01/01/2017.

METHODS

non-random, consecutive sampling. The mean age in this study is 26.10 years. The most common age group of patients who were included in the study was 11-20 years. We had 11 females and 8 males. Female to male ratio was 1.375. The mean duration of symptom was 6.33 years. Most of the patients in our study were students. The mean pre-op ROE score was 29.79 ± 15.28 and post-op score was 87.32 ± 8.75. There was significant improvement in ROE scores following Septorhinoplasty (p < 0.0001). The mean pre-op PNIF score was 76.58 ± 41.37 and post-op score was 125 ± 50.22. There was significant improvement in PNIF scores following surgery (p < 0.0001). There is significant improvement in cosmetic and functional aspects in patients undergoing Septorhinoplasty. There is significant improvement in external appearance and nasal obstruction following Septorhinoplasty. The patient satisfaction following Septorhinoplasty can be measured with ease with the help of Rhinoplasty outcome evaluation questionnaire and Peak nasal inspiratory flow meter.

Synergistic terpene combinations as larvicides against the dengue vector Aedes aegypti Linn

Most of the essential oils (EO) known for mosquitocidal activity contain terpenes as part of their chemical constituents. In this study, four monoterpenes namely γ-terpinene (T), R-(+)-limonene (L), carvacrol (C), and trans-anethole (A) were screened against late third instar Aedes aegypti Linn. larvae singly and in combination to find out the synergistic interaction. The monoterpenes γ-terpinene, R-(+)-limonene, trans-anethole, and carvacrol showed larvicidal activity with LC₅₀ values of 9.76, 11.88, 50.19, 48.57 ppm and LC₉₀ values of 16.99, 17.78, 65.21, 75.02 ppm, respectively for Ae. aegypti when tested individually. Prepared binary combinations at LC₂₀ values and studied the synergistic interactions based on cotoxicity factor (CTF) and found that all the binary combinations showed synergistic interactions (CTF > 20). Further, the binary (1:1), ternary (1:1:1), and quaternary (1:1:1:1) terpene combinations on equal weight basis were prepared, evaluated against Ae. aegypti larvae and synergistic interactions were studied by Wadley's method. Among the eight combinations two combinations viz. LC (LC₅₀ 10.42 ppm) and LA (LC₅₀ 11.86 ppm) were showing synergistic interactions (R > 1.5) and others were exhibiting additive effect (1.5 ≥ R > 0.5) and none of the combinations showed antagonism (R < 0.5). Among the two methods used the Wadley's method found suitable when combinations were made on an equal weight basis. The two binary combinations found in this study are promising synergistic mixtures which has scope in designing mosquito larvicidal EOs by enriching the EOs with terpenes or by producing EO combinations with these terpenes as chemical constituents in the correct proportions.

Larvicidal activity of selected essential oil in synergized combinations against Aedes aegypti

This study was conducted to attain an alternate plant essential oil (EO) based mosquito larvicide against the dengue vector Aedes aegypti. Here three plants were selected based on their local availability, safety and insecticidal properties. EOs were extracted from Syzygium aromaticum (Myrtaceae) flower buds, fruits of Illicium verum (Schisandraceae) and Trachyspermum ammi (Apiaceae) by hydro-distillation and tested against Ae. aegypti larvae individually and in combinations to find synergistic interactions. Chemical constituent analysis of EOs was done by GC/MS/MS analysis and the main constituents in T. ammi were thymol (93.58%) and terpinen-4-ol (2.16%), in S. aromaticum eugenol 56.32% and caryophyllene 17.91% and in I. verum trans-anethole 53.05% and p-anisaldehyde 12.47%. The EOs from T. ammi, I. verum and S. aromaticum and their top components thymol, trans-anethole and eugenol exhibited larvicidal activity with LC₅₀ values 39.48, 41.30, 66.90, 59.76, 50.19 and 60.89 mgL^-1 respectively against Ae. aegypti larvae. The values for the co-toxicity factors for the binary combinations of the EOs were > 20 showing synergistic interactions among the binary mixtures. The respective LC₅₀ values for the 1:1 binary combinations (S. aromaticum + I. verum), (S. aromaticum + T. ammi) and (I. verum + T. ammi) were 49.07, 48.54 and 27.67 mgL^-1. β-cyclodextrin inclusion complex made with I. verum + T. ammi combination showed an LC₅₀ value of 23.93 mgL^-1. On the whole the outcome of this study draw attention to the capability of synergistic EO combinations to emerge as a safe and environment friendly effective larvicide to control Aedes mosquitoes.

Spontaneous Medial Cribriform CSF Leak: Endoscopic Surgical Repair with Free Mucosal Graft-Our Experience

Cribriform plate is the commonest site of spontaneous CSF leak, the fragility of the plate and juxtaposition of arachnoid's investment to the bone, where the olfactory nerve pierces the skull made this area, a vulnerable site for CSF leak. Transnasal endoscopic approach has gained popularity for CSF leak repair over the years. To describe the 5 year experience of spontaneous medial cribriform CSF leak repair with free mucosal graft in a tertiary medical centre. All patients who underwent transnasal endoscopic repair with free mucosal graft for spontaneous medial cribriform CSF leak in our institution between 2011 and 2016 were reviewed. Twelve patients were identified, all were women with a mean age of 44.5 years. The defect was localised by preoperative computed tomography scans with 1 mm cuts and MR cisternography. Via medial approach, the mucosa surrounding the entire defect was denuded and the defect was closed with free mucosal graft harvested either from the middle turbinate or from the nasal septum and middle turbinate was finally sutured with septum to stabilise the repair. The overall success rate was 100% with the first attempt with no recurrence or postoperative complications. Follow up ranged from 1 to 5 years. The endoscopic transnasal technique with free mucosal graft for the repair of spontaneous medial cribriform CSF rhinorrhoea is associated with a very high success rate and it should be considered for majority of cases.

Larvicidal activity of selected plant extracts and their combination against the mosquito vectors Culex quinquefasciatus and Aedes aegypti

In order to develop an environment-friendly botanical mosquito larvicide alternative to the chemical larvicides, extracts were made from the leaves of Hyptis suaveolens, Lantana camara, Nerium oleander, and Tecoma stans with three organic solvents such as methanol (ME), chloroform (CH), and petroleum ether (PE) using a Soxhlet extractor. The plant extracts were screened for larvicidal activity individually and in combination against the larvae of Aedes aegypti and Culex quinquefasciatus as per WHO protocol. Among the extracts, the maximum larvicidal activity was shown by the PE extract of L. camara (LC₅₀ 10.63 mg/L) followed by the PE extract of T. stans (LC₅₀ 19.26 mg/L), ME extract of N. oleander (LC₅₀ 35.82 mg/L), and PE extract of H. suaveolens (LC₅₀ 38.39 mg/L) against Cx. quinquefasciatus. In the case of Ae. aegypti, the PE extract of T. stans showed maximum activity with LC₅₀ value of 55.41 mg/L followed by H. suaveolens (LC₅₀ 64.49 mg/L), PE extract of L. camara (LC₅₀ 74.93 mg/L), and ME extract of N. oleander (LC₅₀ 84.09). A blend of these four extracts resulted in a combination with corresponding LC₅₀ values of 4.32 and 7.19 mg/L against Cx. quinquefasciatus and Ae. aegypti. The predator safety factors were 12.55 and 20.88 for Gambusia affinis with respect to Aedes and Culex larvae for the extract combination. Chemical constituents in extracts were also identified by FT-IR and GC-MS data. The present investigations suggest the possible use of this blend of botanical extracts as an ideal ecofriendly, larvicide against Ae. aegypti and Cx. quinquefasciatus larvae.

Vaccination Status, Knowledge, and Acceptance of Adult Vaccinations against Respiratory Illness among Patients with Type 2 Diabetes Mellitus

Patients with diabetes mellitus are more prone to develop infections with influenza virus and pneumococcus. Once they develop respiratory infections, they are twice more likely to die of complication related to the infection. Although there are no Indian guidelines, recent publications have recommended vaccination in patients with diabetes of all ages. Our study was undertaken to find the barriers to the uptake of adult vaccination against respiratory illness among patients with diabetes attending a diabetic clinic in a tertiary care institution. Of the 149 patients interviewed, only 2% and 0.7% had been previously vaccinated against influenza and pneumococcus, respectively. Although 52% of patients agreed that vaccination was safe and effective, only 17.4% got vaccinated during the period of observation after counseling. The primary reasons for refusal were financial (51.7%), while some were not completely convinced of its benefits (9.4%); the other reasons included fear of complications (7.4%) and needles (0.7%).

Development of a mosquito attractant blend of small molecules against host-seeking Aedes aegypti

A mosquito's dependence on olfaction in the hunt for human host could be efficiently exploited to protect humans from mosquito bites. The present study is undertaken to make the most attractant compound blend for Aedes aegypti mosquitoes to lure them to traps. Eleven molecules (M1-M11) at different dilutions were screened for attractancy against non-blood-fed adult female mosquitoes in an olfactometer. The results showed that the attractancy was dependent on both the chemical nature of the molecule and the strength of the odor. Out of 11 molecules screened, 9 showed significant attractancy (P < 0.05) when tested individually. The attractancy was in the order of M11 > M7 > M6 > M10 > M9 > M3 > M2 > M1 > M4 with attractancy indices (AIs) 86.11, 55.93, 55.17, 54, 52.94, 52, 50, 43.64, and 32, respectively, at the optimum dilutions. Seven blends (I-VII) were made and were screened for attractancy against Ae. aegypti. All the blends showed significant attractancy (P < 0.05). The attractancy was in the order of blend VII > III > IV > I > VI > V > II with AIs 96.63, 89.19, 65, 57.89, 56.1, 47.13, and 44.44, respectively. Among the seven blends, blend VII with constituent molecules M6, M9, M10, and M11 is the most promising with an AI value of 96.63. This blend will be useful in luring the host-seeking mosquitoes to traps. The field efficacy of these attractant blends may be explored in the future.

Anisotropy in surface-initiated melting of the triclinic molecular crystal 1,3,5-triamino-2,4,6-trinitrobenzene: A molecular dynamics study

Surface-initiated melting of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), a triclinic molecular crystal, was investigated using molecular dynamics simulations. Simulations were performed for the three principal crystallographic planes exposed to vacuum, with the normal vectors to the planes given by b × c, c × a, and a × b (where a, b, and c define the edge vectors of the unit cell), denoted as (100), (010), and (001), respectively. The best estimate of the normal melting temperature for TATB is 851 ± 5 K. The nature and extent of disordering of the crystal-vacuum interface depend on the exposed crystallographic face, with the (001) face exhibiting incomplete melting and superheating. This is attributed to the anisotropy of the inter-molecular hydrogen bonding and the propensity of the crystal to form stacking faults in directions approximately perpendicular to the (100) and (010) faces. For all three crystal orientations, formation of molecular vacancies in the lattice at the crystal-vacuum (or crystal-quasi-liquid layer) interface precedes the complete loss of order at the interface.

Mosquito larvicidal and ovicidal activity of puffer fish extracts against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae)

The extracts of liver (LE), ovary (OE), skin (SE) and muscle (ME) tissues of four species of puffer fishes viz., Arothron hispidus, Lagocephalus inermis, Lagocephalus scleratus and Chelonodon patoca were evaluated against larvae and eggs of three mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The LC50 values were 1194.26, 1382.73 (LE); 1421.42, 1982.73 (OE); 7116.86, 15038.98 (ME) and 10817.8 ppm (SE) for An. stephensi and Cx. quinquefasciatus respectively for A. hispidus. In the case of L. inermis, the LC50 values were 1163.83, 1556.1 and 2426.38 (LE); 1653.53, 2734.74 (OE); 6067.47 (ME) and 10283.04 ppm (SE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. The LC50 values were 1509.98, 1608.69 (LE) and 1414.9, 2278.69 ppm (OE) for An. stephensi and Cx. quinquefasciatus respectively for the extracts of L. scleratus. In the case C. patoca extracts the LC50 values were 1182.29, 1543.00, 2441.03 (LE) and 1076.13, 2582.11 ppm (OE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. OE and LE of all puffer fishes exhibited zero percent egg hatchability from 600 to 1000 ppm against eggs of An. stephensi and Cx. quinquefasciatus. This study shows that puffer toxins are effective in killing the larvae and eggs of mosquitoes.

Mosquito attractant blends to trap host seeking Aedes aegypti

Aedes aegypti is the key vector of three important arboviral diseases -dengue, yellow fever and chikungunya. To identify volatile chemicals which could be used in odour based traps for Aedes mosquito surveillance, a few synthetic compounds and compound blends have been evaluated in an indigenously designed olfactometer. A total of 24 compounds and seven compound blends were screened against unfed adult female Ae. aegypti mosquitoes for attraction and compared with control group. The attractancy or repellency index of the test material to mosquitoes was calculated and rated them as class-1, class-2 and class-3 with rating values ranging 1-15, 16-33 and 34-100 respectively. Out of the 24 compounds tested, six were showing significant attractancy (P < 0.05) and among that 1-octene-3-ol showed maximum attractancy with a rating value of 57.81. Sixteen compounds showed significant repellency (P < 0.05) and among that with a rating value of 72.47, 1-hexene-3-ol showed strong repellent action against Ae. aegypti. All the seven blends showed significant mosquito attractancy (P < 0.05) and among that with a rating of 62.08 Myristic acid, Lactic acid and CO(2) blend exhibited first-rate mosquito attractancy.

Development of a controlled release formulation of an indigenous insect growth regulator, DPE-28, a substituted diphenylether, for controlling the breeding of Culex quinquefasciatus

BACKGROUND & OBJECTIVES

DPE-28, a substituted diphenyl ether (2,6-ditertiarybutyl phenyl-2',4'-dinitro phenyl ether) was reported to exhibit promising insect growth regulating activity against Culex quinquefasciatus, the vector of lymphatic filariasis. A controlled release formulation (CRF) of DPE-28 has been developed to control Cx. quinquefasciatus in its breeding habitats. Toxicity of DPE-28, safety to non-target mosquito predators and the release profile of the CRF of DPE-28 are studied and discussed.

METHODS

The acute oral and dermal toxicity was tested in male and female Wistar rats as per the Organization for Economic Cooperation and Development (OECD) guidelines 425 and 402 respectively. The toxicity of DPE-28 to non-target predators was tested as per the reported procedure from this laboratory. The CRF of DPE-28 was prepared by following the reported procedure developed at this laboratory earlier. The concentration of DPE-28 released from the CRF was monitored by HPLC by constructing a calibration graph by plotting the peak area in the Y-axis and the concentration of DPE-28 in the X-axis.

RESULTS

DPE-28 has been tested for acute oral toxicity and found to be moderately toxic with LD 50 value of 1098 mg/kg body weight (b.w). The results of the acute dermal toxicity and skin irritation studies reveal that DPE-28 is safe and non-irritant. DPE-28 when tested at 0.4 mg/litre against non-target mosquito predators did not produce any mortality. The release profile of the active ingredient DPE-28 from the CRF by HPLC technique showed that the average daily release (ADR) of DPE-28 ranged from 0.07 to 5.0 mg/litre during first four weeks. Thereafter the matrix started eroding and the ADR ranged from 5 to 11 mg/litre during the remaining 5 wk. The cumulative release of active ingredient showed that > 90 per cent of the active ingredient was released from the matrix.

INTERPRETATION & CONCLUSIONS

The controlled release matrix of DPE-28 was thus found to inhibit the adult emergence (>80%) of Cx. quinquefasciatus for a period of nine weeks. The CRF of DPE-28 may play a useful role in field and may be recommended for mosquito control programme after evaluating the same under field conditions.

Biochemical studies on glutathione S-transferase from the bovine filarial worm Setaria digitata

Setaria digitata is a filarial worm of the cattle used as a model system for antifilarial drug screening, due to its similarity to the human filarial parasites Wuchereria bancrofti and Brugia malayi. Since filarial glutathione S-transferase (GST) is a good biochemical target for antifilarial drug development, a study has been undertaken for the biochemical characterization of GST from S. digitata. Cytosolic fraction was separated from the crude S.digitata worm homogenate by ultracentrifugation at 100,000 g and subjected to ammonium sulfate precipitation followed by affinity chromatography using GSH-agarose column. The kinetic parameters K (m) and V (max) values with respect to GSH were 0.45 mM and 0.105 μmol min(-1) mL(-1) respectively. With respect to 1-chloro-2,4-dinitrobenzene, the K (m) and V (max) values were 1.21 and 0.117 μmol min(-1) mL(-1) respectively. The effect of temperature and pH on GST enzyme activity was studied. The protein retained its enzyme activity between 0°C and 40°C, beyond which it showed a decreasing tendency, and at 80°C, the activity was lost completely. The enzyme activity was varying with change in pH, and the maximum GST activity was observed at pH 7.5. Gel filtration chromatographic studies indicated that the protein has a native molecular mass of about 54 kDa. The single band of GST subunit appeared in sodium dodecyl sulfate polyacrylamide gel electrophoresis was found to have molecular mass of ∼27 kDa. This shows that cytosolic S. digitata GST protein is homodimeric in nature.

Utility of Topiramate for the Treatment of Patients with Chronic Migraine in the Presence or Absence of Acute Medication Overuse

Chronic migraine has been linked to the excessive use of acute headache medications. Medication overuse (MO) is commonly considered the most significant risk factor for the progression of migraine from an episodic to a chronic condition. Managing MO is a challenge. Discontinuation of the acute medication can result in withdrawal headache, nausea, vomiting and sleep disturbances. This review summarizes the results from two similarly designed, randomized, placebo- controlled, multicentre studies of chronic migraine conducted in the USA and European Union. Both studies demonstrate the efficacy and safety of the migraine preventive medication, topiramate, for the treatment of chronic migraine in patient populations both with and without MO. These studies may have important implications for the future of chronic migraine management, suggesting that detoxification prior to initiating prophylactic therapy may not be required in all patients if MO is present.

Protective effect of vitamin E against carbendazim-induced testicular toxicity–histopathological evidences and reduced residue levels in testis and serum

The fungicide Carbendazim Methyl-2-benzimidazole carbamate (MBC) is known to produce male reproductive toxicity. The present study has been undertaken to investigate the impact of vitamin E, an antioxidant against the testicular toxicity induced by MBC. HPLC analysis showed that the amount of MBC in testis and serum was 57.40 +/- 3.38 nmol/g and 14.10 +/- 0.84 nmol/ml, respectively, in rats treated with carbendazim + vitamin-E, which were significantly lower than that of rats treated with carbendazim alone (240 +/- 15.60 nmol/g and 318.70 +/- 22.52 nmol/ml, respectively). MBC treatment significantly decreased the testicular weight while co-administration of vitamin-E registered normal testicular weight. Histomorphometric analysis revealed a significant decrease (P < 0.05) in the diameter of the seminiferous tubules and lumen in MBC-treated rats compared to control whereas they remained normal in vitamin E + MBC-treated rats. Leydig cells appeared dispersed and hypertrophic after MBC treatment. Various histopathological changes were observed in testis of rats treated with MBC whereas these changes were absent in vitamin-E + MBC-treated rat testis. In conclusion protection against MBC-induced toxicity was observed with co-administration of vitamin E with MBC.

N,N-diethyl phenylacetamide (DEPA): A safe and effective repellent for personal protection against hematophagous arthropods

Repellents play an important role in protecting humans from the bites of insect pests. An effective and safe repellent will be useful in reducing human-vector contact and thereby help in the interruption of vector borne disease transmission. Because of the unavailability of m-toluic acid in India for the manufacture of N,N-diethyl m-toluamide (DEET), there is a need to develop an alternate effective and safe insect repellent. In total, 120 substituted amides were synthesized and tested for repellency at 1.0 mg/cm2 under laboratory conditions. Among these amides, N,N-diethyl phenylacetamide (DEPA), applied at 1.0 mg/cm2 in different oil bases, was found to exhibit promising repellency (6-8 h) in the laboratory when tested against Aedes aegypti (L.) The repellent DEPA was evaluated on army personnel in comparison with dimethylphthalate (DMP) and DEET against mosquitoes, black flies, and land leeches under field condition in the North-East Frontier area of India. Both DEPA and DEET displayed broad-spectrum repellency. DEPA was more effective than DMP against all test organisms. However, no significant difference was noticed between DEPA and DEET for repellency at 0.25 and 0.5 mg/cm2 against black flies and mosquitoes. DMP was the least effective among the three compounds in the field studies. The relative potency of DEPA in comparison with DEET and DMP for repellency against Phlebotomine sand flies also was determined. At 0.1 mg/cm2, both DEPA and DEET were found to be equally effective with a protection time from 4.37 +/- 0.08 to 4.45 +/- 0.15 h. Both compounds were significantly more effective than DMP. At 0.2 mg/cm2, DEPA and DEET provided protection times of 6.52 +/- 0.08 and 7.15 +/- 0.15 h, respectively. DEPA was formulated into a vanishing cream, a pharmacologically safe polymer-based liquid, and a liposphere lotion. The vanishing cream and the two-polymer liquid formulations enhanced protection times from 4.4 to 6.5 and 7.13 h, respectively, compared with an alcohol solution applied at 0.5 mg/cm2 on the forearm of human volunteers. Formulations of DEPA and DEET applied at 0.5 mg/cm2 on rabbits exposed to Ae. aegypti enhanced protection times compared with an alcohol solution and the liposphere lotion from 4.0 to 6.0 h and 4.0 to 5.0 h, respectively. Comparison of mean protection times of DEET and DEPA applied at a rate of 0.3 mg/cm2 to human volunteers exposed to Cx. quinque-fasciatus under field conditions indicated that the lotion formulations of DEET and DEPA provided significantly (Duncan's multiple-range test, P < 0.05) higher protection times than did alcohol solutions. Toxicological studies revealed that DEPA is safe.

Optimization of media composition for the production of cyclosporin A by Tolypocladium species

BACKGROUND & OBJECTIVE

Cyclosporins are produced by certain species of the filamentous fungi, belonging to the genus Tolypocladium. While there are numerous reports on the use of cyclosporins in clinical studies, reports on the various aspects of their production have been very limited. Therefore, this study was carried to optimize the medium composition for the production of cyclosporin A, produced by a strain of the filamentous fungus, Tolypocladium species by static fermentation.

METHODS

The effect of different nutrients on the production of cyclosporin A, produced by Tolypocladium species in stationary culture was studied by growing the fungus for 21 days at 25 +/- 2 degrees C under different media composition. Cyclosporin A was extracted by homogenizing the fungal cells with methanol and the cyclosporin A level was analyzed by high performance liquid chromatography (HPLC).

RESULTS

Among the six different media studied for the production of cyclosporin A, medium 'f' containing glucose (8%), casein acid hydrolysate (3%), malt extract (2%), peptone (1%) and DL- alpha-amino butyric acid (0.5%) favoured the maximum production (2.22 +/- 0.02 g/l medium or 5.85 +/- 0.35 g/kg biomass).

INTERPRETATION & CONCLUSION

This study showed that by optimizing the composition of fermentation media enhanced production of cyclosporin A was obtained. Since the strain Tolypocladium (VCRC F21 NRRL No.18950) produces a high level of cyclosporin A in the identified fermentation medium, it could be exploited for industrial production.

Focus on trial endpoints of clinical relevance and the use of almotriptan for the acute treatment of migraine

Almotriptan is a 5-HT(1B/1D) receptor agonist, or triptan, indicated for the acute treatment of migraine. It has been shown to be effective and well tolerated for the treatment of acute migraine in approximately 5000 patients enrolled in short-term placebo- and active-controlled trials and long-term open-label trials. A recent meta-analysis reported that almotriptan has the highest sustained pain-free (SPF) rate and lowest adverse-event (AE) rate of all oral triptans. Sustained pain free is a composite endpoint of pain freedom at 2 h, no recurrence of moderate-to-severe headache and no use of rescue medication from 2 to 24 h after dosing. Patient surveys have indicated that migraine sufferers consider complete pain relief, no recurrence, rapid onset and no side-effects to be the most important attributes of their acute treatment. Composite endpoints such as SPF and SPF with no AEs (SNAE) contain the attributes that migraine sufferers express as being the most important elements of an acute migraine therapy, and their use in future clinical trials should aid in the selection of agents that can offer patients the highest likelihood of consistent treatment success.

Structure of glutathione S-transferase of the filarial parasite Wuchereria bancrofti: a target for drug development against adult worm

A three dimensional structural model of Glutathione-S-transferase (GST) of the lymphatic filarial parasite Wuchereria bancrofti (wb) was constructed by homology modeling. The three dimensional X-ray crystal structure of porcine pi-class GST with PDB ID: 2gsr-A chain protein with 42% sequential and functional homology was used as the template. The model of wbGST built by MODELLER6v2 was analyzed by the PROCHECK programs. Ramachandran plot analysis showed that 93.5% of the residues are in the core region followed by 5.4 and 1.1% residues in the allowed and generously allowed regions, respectively. None of the non-glycine residues is in disallowed regions. The PROSA II z-score and the energy graph for the final model further confirmed the quality of the modeled structure. The computationally modeled three-dimensional (3D) structure of wbGST has been submitted to the Protein Data Bank (PDB) (PDB ID: 1SFM and RCSB ID: RCSB021668). 1SFM was used for docking with GST inhibitors by Hex4.2 macromolecular docking using spherical polar Fourier correlations.

Development of biodegradable aluminium carboxymethylcellulose matrices for mosquito larvicides

The use of ecofriendly biodegradable controlled-release formulations of mosquito larvicides could reduce the frequency of application and losses due to degradation of the insecticide compared with conventional formulations. Among the 20 matrices developed by entrapping the organophosphorus mosquito larvicide, fenthion, in carboxymethylcellulose ionotropically cross-linked with aluminium ions which were studied for release profiles, two matrices, CRF3b and CRF5b, were found to be stable for 16 and 14 weeks under simulated field conditions. The average concentration of fenthion released per week ranged from 0.06 to 3.5 mg litre(-1) for CRF3b and 0.09 to 2.72 mg litre(-1) for CRF5b. Of these two formulations, CRF3b was the more stable, maintaining the concentration of the active ingredient at the level required to effect mosquito control. The cumulative release of fenthion per pellet was 80% from CRF3b and 72% from CRF5b. Based on the study with fenthion, two similar matrices for triflumuron, a benzoylphenylurea insect growth regulator, STAR3b and STAR5b were developed. These matrices were stable up to 16 weeks with the average concentration of triflumuron released per week ranging from 0.05 to 3.44 mg litre(-1) for STAR3b and 0.07 to 2.71 mg litre(-1) for STARSb. The cumulative release of triflumuron per pellet was 75% from STAR3b and 76% from STAR5b. From the results of this study under simulated conditions, it is estimated that the application of four pellets of either fenthion or triflumuron per square metre of the breeding surface may play a useful role in controlling Culex quinquefasciatus Say in larval habitats for about 4 months.

Trans --> cis isomerization of trans-[(dppm)2Ru(H)(L)][BF4] (L = P(OR)3) complexes: preparation of cis-[(dppm)2Ru(eta2-H2)(L)][BF4]2

A series of new dicationic dihydrogen complexes of ruthenium of the type cis-[(dppm)(2)Ru(eta(2)-H(2))(L)][BF(4)](2) (dppm = Ph(2)PCH(2)PPh(2); L = P(OMe)(3), P(OEt)(3), PF(O(i)Pr)(2)) have been prepared by protonating the precursor hydride complexes cis-[(dppm)(2)Ru(H)(L)][BF(4)] (L = P(OMe)(3), P(OEt)(3), P(O(i)Pr)(3)) using HBF(4).Et(2)O. The cis-[(dppm)(2)Ru(H)(L)][BF(4)] complexes were obtained from the trans hydrides via an isomerization reaction that is acid-accelerated. This isomerization reaction gives mixtures of cis and trans hydride complexes, the ratios of which depend on the cone angles of the phosphite ligands: the greater the cone angle, the greater is the amount of the cis isomer. The eta(2)-H(2) ligand in the dihydrogen complexes is labile, and the loss of H(2) was found to be reversible. The protonation reactions of the starting hydrides with trans PMe(3) or PMe(2)Ph yield mixtures of the cis and the trans hydride complexes; further addition of the acid, however, give trans-[(dppm)(2)Ru(BF(4))Cl]. The roles of the bite angles of the dppm ligand as well as the steric and the electronic properties of the monodentate phosphorus ligands in this series of complexes are discussed. X-ray crystal structures of trans-[(dppm)(2)Ru(H)(P(OMe)(3))][BF(4)], cis-[(dppm)(2)Ru(H)(P(OMe)(3))][BF(4)], and cis-[(dppm)(2)Ru(H)(P(O(i)Pr)(3))][BF(4)] complexes have been determined.