Model nematodes as a practical innovation to promote high throughput screening of natural products for anthelmintics discovery in South Asia: Current challenges, proposed practical and conceptual solutions

With the increasing prevalence of anthelmintic resistance in animals recorded globally, and the threat of resistance in human helminths, the need for novel anthelmintic drugs is greater than ever. Most research aimed at discovering novel anthelmintic leads relies on high throughput screening (HTS) of large libraries of synthetic small molecules in industrial and academic settings in developed countries, even though it is the tropical countries that are most plagued by helminth infections. Tropical countries, however, have the advantage of possessing a rich flora that may yield natural products (NP) with promising anthelmintic activity. Focusing on South Asia, which produces one of the world's highest research outputs in NP and NP-based anthelmintic discovery, we find that limited basic research and funding, a lack of awareness of the utility of model organisms, poor industry-academia partnerships and lack of technological innovations greatly limit anthelmintics research in the region. Here we propose that utilizing model organisms including the free-living nematode Caenorhabditis elegans, that can potentially allow rapid target identification of novel anthelmintics, and Oscheius tipulae, a closely related, free-living nematode which is found abundantly in soil in hotter temperatures, could be a much-needed innovation that can enable cost-effective and efficient HTS of NPs for discovering compounds with anthelmintic/antiparasitic potential in South Asia and other tropical regions that historically have devoted limited funding for such research. Additionally, increased collaborations at the national, regional and international level between parasitologists and pharmacologists/ethnobotanists, setting up government-industry-academia partnerships to fund academic research, creating a centralized, regional collection of plant extracts or purified NPs as a dereplication strategy and HTS library, and holding regional C. elegans/O. tipulae-based anthelmintics workshops and conferences to share knowledge and resources regarding model organisms may collectively promote and foster a NP-based anthelmintics landscape in South Asia and beyond.

Molecular and phylogenetic characterization of zoonotic Trichostrongylus species from goats for the first time in Bangladesh

BACKGROUND

Trichostrongylus is one of the most important nematodes infecting animals and humans. The current study was designed to identify the Trichostrongylus species infecting goats by multiplex PCR and phylogenetic analysis.

METHODS

A total of 124 goats' viscera were collected from different abattoirs of Mymensingh division. Trichostrongylus species were isolated and characterized based on morphometry, multiplex PCR and phylogenetic analysis.

RESULTS

Among 124 viscera of goats, 39 were positive with two species, Trichostrongylus colubriformis and Trichostrongylus vitrinus, revealing an overall 31.45% prevalence. Morphological identification of Trichostrongylus species was confirmed by multiplex PCR amplification of the ITS2 gene and sequencing. Partial sequencing of the ITS2 gene of two species revealed seven single nucleotide polymorphisms (three transitions and four transversions) in this study. The neighbor-joining phylogenetic tree demonstrated that T. colubriformis and T. vitrinus isolates were clustered together with the reference sequences that belong to the clade A and B without any geographical boundaries.

CONCLUSIONS

This is the first report on molecular and phylogenetic analysis of Trichostrongylus species from ruminants in Bangladesh. These results provide the baseline data for understanding the zoonosis and epidemiology of this parasite in Bangladesh and global perspectives.

Molecular detection of Babesia and Theileria from crossbred cattle in Sirajganj and Rangpur districts of Bangladesh

BACKGROUND

Babesia and Theileria are potential threats to the livestock industry, causing considerable economic losses. These tick-borne blood parasites are more prevalent in crossbred cattle than local cattle in Bangladesh.

OBJECTIVES

To confirm the species of Babesia and Theileria in crossbred cattle from the northern part of Bangladesh using conventional and molecular tools.

METHODS

A total of 385 crossbred cattle blood samples were subjected to DNA extraction and PCR. For molecular detection, B. bigemina rhoptry-associated protein 1a, B. bovis spherical body protein-4, and Theileria spp. 18S rRNA were used as the marker genes.

RESULTS

Using PCR, only 72 (18.7%) samples were found piroplasm positive, of which 12.2% Theileria, 4.7% Babesia, and 1.8% mixed infections. Both Babesia (7.3%), Theileria (7.7%) and mixed (2.8%) infections were detected in Sirajganj, and only Theileria (20.4%) was detected in Rangpur district. By PCR and nPCR we detected B. bigemina and T. annulata in Sirajganj district, and Theileria sp. in Rangpur district. The target gene sequences of isolated pathogens confirmed B. bigemina and T. annulata, and Theileria sp from these samples. Blood smears of all samples were also examined microscopically for Babesia and/or Theileria spp. and 14.3% of samples were found positive, of which 5.9% Babesia and 8.3% Theileria. Generally, the pathogens detected in Sirajgang and Rangpur were genetically related to South Asia, particularly South East Asian isolates.

CONCLUSIONS

These findings provide information for a better understanding of the epidemiology of Babesia and Theileria as well as to improve the approaches for diagnosis and control of tick-borne diseases in Bangladesh.

Efficacy of clinically used anthelmintics against toxocariasis of buffalo calves in Bangladesh

Toxocariasis is a paramount parasitic disease having > 50% prevalence among newborn buffalo calves in Bangladesh. The objective of this study was to compare the efficacy of clinically used anthelmintics and their subsequent effect on the haematological parameters and body weight in buffalo calves in commercial buffalo farms in coastal region. Thirty-two buffalo calves below 3 months of age with clinical Toxocara infection had been selected and treated with albendazole (ABZ), levamisole (LVM) and ivermectin (IVM). The EPG counts, hematological parameters and initial body weight of buffalo calves were recorded on the day of anthelmintic treatment (day 0). Fecal samples were collected on day 14 and 28 including hematological parameters and body weight were recorded on day 28 post-treatment. The efficacy (%) of anthelmintics were estimated by fecal egg count reduction test (FECRT). The parameters like Hb, PCV, ESR, TEC, TLC were analyzed from the blood samples. The FECRT revealed 96.83% efficacy for IVM followed by 94.23% and 85.84% for LVM and ABZ, respectively. Anthelmintic treated calves showed significant (p < 0.01) increase in Hb, PCV, TEC and body weight, and decrease in ESR and TLC as a result of worm expulsion from buffalo calves after 28 days of post-treatment. Among the tested anthelmintics, IVM was found to be more effective against toxocariasis in buffalo calves. This is a novel information on anthelmintics efficacy in buffalo calves in Bangladesh. Details study is recommended on the efficacy of anthelmintics in different buffalo management systems by in vitro egg hatch assay (EHA) test.

Efficacy of flukicides on Fasciola gigantica, a food-borne zoonotic helminth affecting livestock in Bangladesh

Fasciola gigantica, the causative agent of tropical fasciolosis, is a food-borne zoonotic trematode that affects around 80% livestock of Bangladesh. Triclabendazole (TCBZ), nitroxynil (NTON) and oxyclozanide (OCZN) are frequently used against fascioliasis; however, the current status of potency of these flukicides was unknown. In this study, in vitro efficacy of TCBZ, NTON and OCZN at various concentrations on F. gigantica has been evaluated by relative motility (RM), morphological distortions of apical cone through an inverted microscope, architectural and ultra-structural changes through histopathological and scanning electron microscopy (SEM). It is observed that TCBZ, NTON and OCZN at higher concentrations significantly (P < 0.05) reduced RM of the flukes compared to untreated control. NTON at 150 μg mL−1 was the most potent to reduce the motility within 4 h whereas TCBZ and OCZN were much delayed. Histopathological changes showed swollen, extensive cracking, numerous vacuoles and splitting of the tegument surrounding the spines; spine dislodged from its socket in treated flukes compared to untreated worms. Histopathological changes were more conspicuous at higher doses of TCBZ, NTON and OCZN. SEM has shown the disruption of the apical cone, apart from swelling of the tegument on the ventral surface corrugation and disruption of the ventral apical cone. All these changes indicate that NTON is the most potent in killing flukes in vitro among the tested flukicides and suggest the presence of TCBZ-resistant fluke populations in Bangladesh. It is imperative to explore the in vivo effects of these flukicides and subsequently their molecular mechanisms.

Prevalence of hookworm infections among stray dogs and molecular identification of hookworm species for the first time in Bangladesh

Hookworms are the most common and voracious blood-sucking parasites of the small intestines of mammalian hosts such as dogs, cats, ruminants and humans. Canine hookworms are endemic in the Southeast Asian countries including Bangladesh. There is scarcity of information on the prevalence of hookworms of stray dogs in Bangladesh. The present study determined the prevalence of canine hookworms using fecal examination followed by morphometric and molecular identification. Fecal samples were collected from 320 stray dogs living in rural areas of Mymensingh district (Gauripur upazila, Mymensingh sadar upazila and Tarakanda upazila) and hookworm eggs were identified using the flotation techniques. The overall prevalence of hookworm was 79.1% through microscopic examination. Estimated fecal prevalence was higher in Gauripur upazila (89.7%) followed by Mymensingh sadar upazila (84.8%) and Tarakanda upazila (53.2%). Five hookworm species were identified based on the morphometric examination, namely, Ancylostoma caninum, Ancylostoma ceylanicum, Ancylostoma tubaeforme, Ancylostoma braziliense and Ancylostoma duodenale, respectively. Polymerase Chain Reaction (PCR) was performed with the genomic DNA by targeting the 5.8S rRNA (~ 404 bp) and Cytochrome oxidase-1 (Cox 1, ~ 450 bp) and confirmed the identification for the first time in Bangladesh. This study reveals that stray dogs may act as reservoir hosts of human hookworm infection. Further detail molecular study is warranted to explore the genetic diversity of hookworms that infect both dogs and human in Bangladesh.

Prevalence and risk factors of Toxocara vitulorum infection in buffalo calves in coastal, northeastern and northwestern regions of Bangladesh

Buffalo (Bubalus bubalis) is popularly known as the black gold of South Asia, consisting of 97% of the world buffalo population. Among the parasitic infections, Toxocara vitulorum is one of the most common and harmful parasites of buffalo calves in Bangladesh. A cross-sectional study was conducted to explore the prevalence and associated risk factors of T. vitulorum infection of buffalo calves in four regions of Bangladesh. A total of 1751 fecal samples were collected and examined using flotation followed by the McMaster technique for counting the eggs per gram of feces (EPG) of T. vitulorum. The overall prevalence of T. vitulorum infection in buffalo calves was 22.9%. Significantly (p < 0.001) higher prevalence was found in the Barishal coastal area (35.7%) followed by Chattogram coastal area (29.2%), northeastern region (15.5%) and northwestern region (8.3%). Buffalo calves aged 1-3 months were heavily infected with T. vitulorum (51.7%) which was statistically different (p < 0.001) compared to those >3-6 months (27.6%) and > 6-12 months (6.5%). According to univariate analysis, coastal regions, rainy season, young age, gender, indigenous river type, buffalo calves with poor body condition and soft feces were found significantly associated with T. vitulorum infections. Coastal regions, rainy season and young age were identified as the risk factors of T. vitulorum infection in buffalo calves by final logistic regression model. This study reveals that T. vitulorum infection is endemic in Bangladesh and widely distributed in the coastal regions. Therefore, attention to buffalo calves regarding in-depth clinical effects and current therapeutic approaches against this nematode should be evaluated along with the economic impact of infection. Exploring the genetic diversity of T. vitulorum may help to reveal the host-parasite relationship in the future.

Need Assessment for Updating the MBBS Curriculum 2012 of Bangladesh

Curriculum is the road map of any course and an instrument for developing the competencies of the human resources. The MBBS curriculum in our country was last updated in 2012 during the period of Millennium Development Goals (MDGs). Since then it has been under implementation in different government, non-government and Army medical colleges in association with different universities. "Health Professional for a New Century" now asks for a transformation of the education to strengthen the health systems for meeting the challenges of the 21st century. Curriculum reform is an important issue in transformative education and need assessment is the first and essential task to review and update any curriculum. The objective of the study was to assess the need to review and update the MBBS curriculum 2012 of Bangladesh. Review and updating of MBBS curriculum was organized by Centre for Medical Education (CME) and supported by World Health Organization (WHO). CME, DGHS, Dean offices, MOH&FW, BM&DC and all the government and non-government medical colleges were involved in this activity. Duration of study was 7 months from April 2019 to October 2019. Data were collected from academic councils of 102 medical colleges through structured questionnaire and through FGD with teachers and interns. Around 90(88.2%) academic councils agreed and 12(12%) disagreed about the appropriateness of existing four phases of MBBS curriculum. About 80(84.2%) academic councils agreed with 1.5 years duration of Phase I, 84(88.4%) agreed with one year duration of Phase II, 84(94.4%) agreed with one year duration of Phase III and 77(84.6%) agreed with 1.5 years duration of Phase IV. The study suggested the subjects for 2nd phase are, Pharmacology 74(84.1%), Pathology 53(60.3%), Forensic Medicine 46(52.3%), and for 3rd phase are Community Medicine 60(69.8%), Microbiology 54(62.8%). The study revealed that the subjects of overloaded contents are, Anatomy - 24(50%), Community Medicine - 35(72.9%) and Pathology - 19(39.6%). The study suggested incorporation of organized teaching-learning for behavioral science, communication skills, ethics and development of attitude by most of the academic councils. The study suggested that the increased duration of ambulatory care (outdoor/emergency) teaching. The study revealed around 84(83.2%) academic councils recommended that Single Best Answer (SBA) type of questions should be included in MCQ part for all subjects along with multiple true-false response and around 82(81.2%) academic councils recommended that Structured Essay Question (SEQ) should be included in written part along with Short Answer Question (SAQ). The study revealed that 58(58.6%) academic councils recommended that carry-on system should not be in Phase I and 53(53.5%) academic councils opined to introduce grading system in MBBS course. Most of the academic councils agreed about the appropriateness of existing four phases of MBBS curriculum. The subjects for 2nd phase are, Pharmacology - 84.1%, Pathology - 60.3%, Forensic Medicine - 52.3%, and for 3rd phase are Community Medicine - 69.8%, Microbiology - 62.8%. Most of the participants are in favour of the present curriculum components, grading system for assessment but not the carry-on system in Phase I. The study recommended for national level consultations involving the concerned persons for finalization of the MBBS curriculum.

Peste des Petits Ruminants Risk Factors and Space-Time Clusters in Bangladesh

Peste des Petits Ruminants (PPR) is endemic in Bangladesh, but its spatial distribution and risk factors have not yet been reported. Using four years of national-level, passive surveillance data (2014 to 2017), in this study we aimed to identify risk factors, create PPR risk maps and describe PPR time-space clusters. We selected PPR case records—mainly based on presumptive diagnosis of small ruminants in subdistrict veterinary hospitals—and sheep and goat population data from all 64 districts of Bangladesh. Peste des Petits Ruminants cumulative incidence per 10,000 animals at risk per district was used to conduct cluster and hotspot analysis and create predictive maps for each year and all 4 years combined. The association between PPR cumulative incidence and hypothesized risk factors—including climatic variables, elevation, road length, river length, railroad length, land cover, and water bodies—was analyzed using a geographically weighted regression model. The total number of PPR cases reported during the study period was 5.2 million. We found that most PPR cases (27.6%) were reported in the monsoon season. The highest and lowest proportions of cases were reported from Rajshahi (36.1%) and Barisal divisions (2.1%), respectively. We identified five space-time clusters, 9 high–high clusters, and 9 hotspots. The predicted cumulative incidences of PPR were persistently higher in north-east, north-west, and south-east parts of Bangladesh. Road length (P = 0.03) was positively associated with PPR incidence in Bangladesh. Results suggest that movement of animals (road length) plays an important role in the epidemiology of PPR in Bangladesh. Along with restriction of animal movement, hotspots and high–high clusters should be targeted first for immunization coverage in Bangladesh and similar PPR endemic countries to achieve eradication.

Foot-and-Mouth Disease Space-Time Clusters and Risk Factors in Cattle and Buffalo in Bangladesh

Foot-and-mouth disease (FMD) is highly endemic in Bangladesh. Using passive surveillance data (case records from all 64 districts of Bangladesh, 2014–2017) and district domestic ruminant population estimates, we calculated FMD cumulative incidence per 10,000 animals at risk per district, conducted cluster (Moran’s spatial autocorrelation and scan statistics) and hotspot analysis (local indicator of spatial association statistic), created predictive maps and identified risk factors using a geographically weighted regression model. A total of 548,817 FMD cases in cattle and buffalo were reported during the four-year study period. The highest proportion (31.5%) of cases were reported during the post-monsoon season, and from Chattogram (29.2%) division. Five space-time clusters, 9 local clusters, and 14 hotspots were identified. Overall, higher cumulative incidences of FMD were consistently predicted in eastern parts of Bangladesh. The precipitation in the pre-monsoon season (p = 0.0008) was positively associated with FMD in Bangladesh. Results suggest climate plays an important role in the epidemiology of FMD in Bangladesh, and high risk zones exist. In a resource limited-setting, hotspots and clusters should be prioritized for vaccination coverage, and surveillance for FMD should be targeted in eastern areas of Bangladesh and during the post-monsoon season.

Molecular detection of Toxoplasma gondii from aborted fetuses of sheep, goats and cattle in Bangladesh

The study was planned to apply the PCR method for detection of T. gondii infection in sheep, goats and cattle aborted fetuses from Mymensingh, Bangladesh. A total of 58 fetal tissue samples (brain, liver, heart, skeletal muscle and placenta) of sheep (5), goats (5) and cattle (2) were selected for study. Aborted fetuses were taken from serologically positive mothers by indirect ELISA. Among them 24 and 34 samples were subjected for PCR assay by using TgB1 and TgTox4 primers respectively. DNA fragments were visualized under UV illumination after gel run. The results demonstrated 15.52% tissue samples from sheep and goat aborted fetuses were positive for T. gondii parasite. Among different tissue samples, brain, liver and heart showed presence of T. gondii parasite. None of tissue samples showed positive in case of cattle. The results of the PCR exhibited that T. gondii infection might be considered as one of the major causative agents for abortion in ewes and does. Further studies are needed to improve our knowledge on different genotypes of T. gondii that infect sheep, goat and cattle population in Bangladesh.

Status of anthelmintic resistance of gastrointestinal nematodes in organized sheep and goat farms

Anthelmintic resistance has become a global problem that threatens livestock production worldwide. The present study was investigated the status of anthelmintic resistance in gastrointestinal (GI) nematodes of small ruminants in two organized sheep and goat farms in two different areas of Bangladesh by fecal egg count reduction test (FECRT) for albendazole, levamisole and ivermectin. In each farms, naturally infected animals were divided into four groups of 10 animals. Fecal samples from each group were collected on day 0 and day 14 of post treatment to measure the eggs per gram of feces (EPG). The fecal samples of each group before and after treatment were also considered for culture to identify resistant parasite. In case of organized sheep farm, the result of FECRT of albendazole was 90.17, 95% confidence with upper and lower limit was 97.82 and 55.68, respectively. The result of FECRT of levamisole and ivermectin was 98.25 and 96.77, 95% confidence with upper and lower limit was 99.79, 85.12 and 99.11, 88.31, respectively. In case of organized goat farm, the result of FECRT of albendazole was 100, 95% confidence with upper and lower limit was 0 and 0, respectively. The result of FECRT of levamisole and ivermectin was 97.99 and 100, 95% confidence with upper and lower limit was 99.59, 90.28 and 0, 0 respectively. The results revealed that gastrointestinal nematodes were found to be resistant to albendazole in organized sheep farm and suspected to be resistant to levamisole and ivermectin. In organized goat farms, the GI nematodes found to be susceptible to all anthelmintics used for this study. Coproculture revealed that Haemonchus spp. were resistant parasite in sheep farm. This seems to be the first documentation of anthelmintic resistance against GI nematodes in organized sheep and goat farms in Bangladesh. Appropriate measures need to be taken to overcome the situation. Asian J. Med. Biol. Res. December 2018, 4(4): 378-382

Anthelmintic resistance to cattle gastrointestinal nematodes in selected dairy farms of Mymensingh and Sirajganj districts of Bangladesh

Correction: Table 1 and Table 2 have were omitted from the PDF in error. They were added to page 89 on 17th May 2018.Anthelmintic resistance (AR) to commonly used dewormers is one of the major world-wide constrain in livestock production. The present study was investigated the status of AR in BAU dairy farm, Mymensingh and Talukder dairy farm, Sirajganj. Faecal egg count reduction test (FECRT) was applied to assess AR in cattle of two dairy farms during January to June 2017. The anthelmintics tested were Albendazole (ABZ), a benzimidazole anthelmintic (Almex®, Square Ltd.) and Ivermectin (IVM) (Vermic®, Techno drugs Ltd.), administered at the doses recommended by the manufacturers. In each farm, cattle were divided into treatment and control (not treated) group based on faecal egg counts (FEC), that is at least 200 eggs/g. At 14 days after treatment, faecal samples were collected for post-treatment FEC, which is compared between treatment and control group. Resistance was defined if there was <95% reduction, with lower 95% confidence limit (CL) <90% in the FEC. AR was present in both the dairy farms involved in this study. The FECRT using ABZ revealed 79.7% (95% CL 87.9, 65.8) reduction and 95.8% (95% CL 98.7, 87.1) reduction of FEC in BAU and Talukder dairy farms, respectively. Also, FECRT using IVM revealed 77.9% (95% CL 97.7, 85.5) and 94.2% (95% CL 97.7, 85.5) reduction of FEC in BAU and Talukder dairy farms, respectively. Our study suggest that AR is present in both selected dairy farms and further extensive studies are required to determine the extent of AR in different cattle farms of Bangladesh.Res. Agric., Livest. Fish.5(1): 87-92, April 2018

Characterization of Trichuris muris secreted proteins and extracellular vesicles provides new insights into host-parasite communication

Whipworms are parasitic nematodes that live in the gut of more than 500 million people worldwide. Owing to the difficulty in obtaining parasite material, the mouse whipworm Trichuris muris has been extensively used as a model to study human whipworm infections. These nematodes secrete a multitude of compounds that interact with host tissues where they orchestrate a parasitic existence. Herein we provide the first comprehensive characterization of the excretory/secretory products of T. muris. We identify 148 proteins secreted by T. muris and show for the first time that the mouse whipworm secretes exosome-like extracellular vesicles (EVs) that can interact with host cells. We use an Optiprep® gradient to purify the EVs, highlighting the suitability of this method for purifying EVs secreted by a parasitic nematode. We also characterize the proteomic and genomic content of the EVs, identifying >350 proteins, 56 miRNAs (22 novel) and 475 full-length mRNA transcripts mapping to T. muris gene models. Many of the miRNAs putatively mapped to mouse genes are involved in regulation of inflammation, implying a role in parasite-driven immunomodulation. In addition, for the first time to our knowledge, colonic organoids have been used to demonstrate the internalization of parasite EVs by host cells. Understanding how parasites interact with their host is crucial to develop new control measures. This first characterization of the proteins and EVs secreted by T. muris provides important information on whipworm-host communication and forms the basis for future studies.

Fascioliasis risk factors and space-time clusters in domestic ruminants in Bangladesh

Background

A retrospective observational study was conducted to identify fascioliasis hotspots, clusters, potential risk factors and to map fascioliasis risk in domestic ruminants in Bangladesh. Cases of fascioliasis in cattle, buffalo, sheep and goats from all districts in Bangladesh between 2011 and 2013 were identified via secondary surveillance data from the Department of Livestock Services’ Epidemiology Unit. From each case report, date of report, species affected and district data were extracted. The total number of domestic ruminants in each district was used to calculate fascioliasis cases per ten thousand animals at risk per district, and this was used for cluster and hotspot analysis. Clustering was assessed with Moran’s spatial autocorrelation statistic, hotspots with the local indicator of spatial association (LISA) statistic and space-time clusters with the scan statistic (Poisson model). The association between district fascioliasis prevalence and climate (temperature, precipitation), elevation, land cover and water bodies was investigated using a spatial regression model.

Results

A total of 1,723,971 cases of fascioliasis were reported in the three-year study period in cattle (1,164,560), goats (424,314), buffalo (88,924) and sheep (46,173). A total of nine hotspots were identified; one of these persisted in each of the three years. Only two local clusters were found. Five space-time clusters located within 22 districts were also identified. Annual risk maps of fascioliasis cases correlated with the hotspots and clusters detected. Cultivated and managed (P < 0.001) and artificial surface (P = 0.04) land cover areas, and elevation (P = 0.003) were positively and negatively associated with fascioliasis in Bangladesh, respectively.

Conclusions

Results indicate that due to land use characteristics some areas of Bangladesh are at greater risk of fascioliasis. The potential risk factors, hot spots and clusters identified in this study can be used to guide science-based treatment and control decisions for fascioliasis in Bangladesh and in other similar geo-climatic zones throughout the world.

Development of in vitro atovaquone-resistant Babesia gibsoni with a single-nucleotide polymorphism in cytb

An atovaquone (ATV)-resistant Babesia gibsoni was developed by in vitro exposure of uncloned wild type (WT) B. gibsoni to 800 nM ATV for 6 days. Sequence analysis of mitochondrial genes showed a single-nucleotide polymorphism (SNP) at cytb nt363 (G to T) that resulted in the substitution of methionine with isoleucine (M121I), which is one of the SNPs reported in a previous in vivo study. 363T or 363G allele-specific real-time polymerase chain reaction (PCR) revealed that an M121I variant was present in over 99% of the ATV-resistant population. As neither ATV resistance nor gene polymorphisms appeared in the B. gibsoni WT sibling clones, the expression of ATV resistance in this study was suspected to be because of selective multiplication of the B. gibsoni M121I variant. This ATV-resistant B. gibsoni displayed the same sensitivity as the WT B. gibsoni against 5 other drugs, including diminazene aceturate, azithromycin, doxycycline, clindamycin, and proguanil. This is the first report on the in vitro establishment of an ATV-resistant B. gibsoni with gene polymorphisms.

Antagonistic effects of atipamezole and yohimbine on medetomidine-induced diuresis in healthy dogs

This study aimed to investigate and compare the antagonistic effects of atipamezole and yohimbine on medetomidine-induced diuresis in healthy dogs. Five dogs were used repeatedly in each of 8 groups. One group was not medicated. Dogs in the other groups received 20 microg/kg of medetomidine intramuscularly and, 0.5 h later, saline (as the control injection), 50, 100, or 300 microg/kg of atipamezole, or 50, 100, or 300 microg/kg of yohimbine intramuscularly. Urine and blood samples were taken 11 times over 24 h for measurement of the following: urine volume, specific gravity, and creatinine concentration; urine and plasma osmolality; urine and plasma concentrations of electrolytes and arginine vasopressin (AVP); and the plasma concentration of atrial natriuretic peptide (ANP). Both atipamezole and yohimbine antagonized the diuretic effect of medetomidine, inhibiting medetomidine-induced decreases in urine specific gravity, osmolality, and concentrations of creatinine, sodium, potassium, chloride, and AVP and reversing both the medetomidine-induced increase in plasma concentrations of sodium, potassium, and chloride and the medetomidine-induced decrease in the plasma AVP concentration. Atipamezole significantly stimulated ANP release. The antidiuretic action of yohimbine was more potent than that of atipamezole but was not dose-dependent, in contrast to the action of atipamezole. The effects of these drugs may not be due only to actions mediated by alpha(2)-adrenoceptors.

Diuretic effects of medetomidine compared with xylazine in healthy dogs

This study aimed to investigate and compare the effects of medetomidine and xylazine on diuretic and hormonal variables in healthy dogs. Five dogs, used in each of 11 groups, were injected intramuscularly with physiological saline solution (control), 5, 10, 20, 40, and 80 microg/kg of medetomidine, and 0.25, 0.5, 1, 2, and 4 mg/kg of xylazine. Urine and blood samples were taken 11 times over 24 h. Both medetomidine and xylazine increased urine production in a dose-dependent manner up to 4 h after injection, but the increase was much less with medetomidine than with xylazine at the tested doses. Urine specific gravity, pH, osmolality, and concentrations of creatinine, sodium, potassium, chloride, and arginine vasopressin (AVP) were decreased in a dose-dependent manner with both medetomidine and xylazine. Plasma osmolality and concentrations of sodium, potassium, and chloride were increased significantly with both drugs. Total amounts of urine AVP excreted and plasma AVP concentrations were significantly decreased by higher doses of medetomidine but were not significantly decreased by xylazine. Higher doses of both drugs significantly increased the plasma concentration of atrial natriuretic peptide (ANP), but the effect was greater with medetomidine than with xylazine. The results revealed that both drugs induce a profound diuresis, but medetomidine's effect is less dose-dependent than xylazine's effect. Although changes in plasma concentrations of AVP and ANP may partially influence the diuresis induced by medetomidine, other factors may be involved in the mechanism of the diuretic response to both drugs. Thus, both agents can be used clinically for transient but effective diuresis accompanied by sedation.

Pattern of cancer in young adults at National Institute of Cancer Research and Hospital (NICRH), Bangladesh

This is an analysis of 1624 young adults (20-44 years) new cancer patients who attended Out Patient Department of NICRH in 2005 from 01 January to 31 December. This study was carried out to know the age and sex distribution and types of cancer they are suffering from. Histologiacally or cytologically confirmed patients or those patients having radiological or clinical evidence of malignancy were included in the study. There were 42.9% male and 57.1% female with male to female ratio of 0.75: 1.00. Female populations of this age group were the most cancer sufferers. Mean age of young adults was 34.47 (SD+/-6.33) years. Muslims (93.4%) were in majority and 36.5% were illiterate. This study revealed that the top five cancers found in both sexes were breast cancer (19.2%), female genital organ cancer (17.7%), GIT cancer (13.5%), head & neck cancer (12.2%) and respiratory tract cancer (7.9%). Breast cancer and GIT cancer ranked top among females and males respectively.