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Biomedical subjects

R A Khan

Publications and source records attributed to R A Khan.

At least 19 recordsLinked to original sources
PubMed2006

Parasites of winter flounder (Pleuronectes americanus) as an additional bioindicator of stress-related exposure to untreated pulp and paper mill effluent: a 5-year field study.

A study was conducted in a marine inlet to assess the effects of untreated discharges from a pulp and paper mill, a municipality, and industries in western Newfoundland on winter flounder (Pleuronectes americanus), a fish species shown previously to be sensitive to environmental contaminants in sediment. The fish were captured by SCUBA divers about 2 km down-current from the mill discharging effluent containing resin acids, and at three reference sites 2 to 11 km away near the opposite shore, each spring in five consecutive years and the fish were necropsied on site. A total of 360 and 339 flounder were examined near the mill and references sites, respectively. Several bioindicators were used to assess fish health including parasites. More fish exhibiting external and microscopic lesions in several tissues, lower condition factors, elevated hepatosomatic index, and delayed reproductive development were observed in samples taken near the paper mill than at the reference sites. A higher prevalence of an ectoparasite, Cryptocotyle lingua, but a significantly lower mean abundance of three metazoans infecting the digestive tract was noted in fish near the mill than in the reference samples. These results, comprising abnormal fish size distribution, low body condition factor, external and internal lesions, enlarged liver, delayed gonadal development, and changes in parasitism, were stress-related, indicative of impaired health, and associated primarily with untreated discharges from the pulp and paper mill. This integrated and multidisciplinary study also provides further evidence on the use of fish parasites as a valid and an additional bioindicator in programs monitoring environmental contaminants.

Analysis of Variance↗
PubMed2006

Assessment of stress-related bioindicators in winter flounder (Pleuronectes americanus) exposed to discharges from a pulp and paper mill in Newfoundland: a 5-year field study.

This study assessed the effects of discharges from a sulphite-bleaching paper mill on winter flounder (Pleuronectes americanus) sampled each spring over a 5-year period in St. George's Bay, Newfoundland, prior to foraging activity. The fish were captured by SCUBA divers near the mill and at a reference site 10 km up current. Several bioindicators were used to assess fish health. Larger and older flounder exhibiting gross and microscopic tissue lesions, lower condition factor, and elevated hepatosomatic index but lower gonadosomatic index that was associated with delayed development, were observed in samples caught near the mill compared to those at the reference site. Additionally, fish examined near the mill were infested with an ectoparasite, Cryptocotyle lingua, that causes black spot disease but harbored fewer numbers of a digene, Steringophorus furciger, in the digestive tract than samples taken at the reference site. These results suggest that abnormal size distribution, interruption of growth, high prevalence of lesions, lower condition factor, enlarged liver, delayed gonadal development, and differences in parasitic levels were indicative of stress in winter flounder caused by discharges from the mill compared to samples from a reference site. There was no evidence of a population decline in the inlet because of annual recruitment possibly from St. George's Bay into which it opens.

Animals↗
PubMed2006

Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada.

A study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotyle reflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

Animals↗
PubMed2006

Prevalence of Sarcocystis spp. in two subspecies of caribou (Rangifer tarandus) in Newfoundland and Labrador, and foxes (Vulpes vulpes), wolves (Canis lupus), and husky dogs (Canis familiaris) as potential definitive hosts.

A study was conducted to determine the prevalence and geographical distribution of Sarcocystis spp. infecting 2 subspecies of caribou (Rangifer tarandus) inhabiting Newfoundland and Labrador and its potential definitive hosts. Muscle samples of caribou were obtained, primarily from hunters, and feces of red foxes (Vulpes vulpes) and wolves (Canis lupus), from trappers, and Husky dogs (Canis familiaris), from owners. Histological sections of muscle and flotation methods for feces were used for parasitic detection. Sarcocystis sp. infected more than 50% of barren-ground caribou (R. t. tarandus) from 4 locations in Newfoundland, but it was significantly greater in the north, where 99% of woodland caribou (R. t. caribou) from Labrador harbored the infection. Sporocysts were observed in 27 of 32 red foxes from eastern and northern Newfoundland, whereas 15 of 15 wolves and 22 of the 38 Husky dogs were infected. Wolves and red foxes probably acquired the infection through scavenging, and Husky dogs, from meat they were fed.

Animals↗
PubMed2005

Prevalence and influence of Loma branchialis (Microspora) on growth and mortality in Atlantic cod (Gadus morhua) in coastal Newfoundland.

A study was conducted to determine the prevalence, geographical distribution, and effects of a microsporan parasite, Loma branchialis, in Atlantic cod in coastal Newfoundland. The parasite was identified microscopically as opaque, ovoid xenomas, primarily in the gills, heart, and spleen. Although widely distributed in young fish inhabiting 7 coastal localities, prevalence was 1-7% in general, <0.01% in older and large fish, but 78% in market-size cod from a commercial farm. Some of the latter fish were emaciated, and approximately 2 mo after the parasite was detected, 63% succumbed with a massive infection. Condition factor and blood values were significantly lower than those in reference fish. An experimental study conducted over 2 yr revealed that mass gained and condition factor were significantly lower in infected cod than in controls at the termination of the study. Feed consumption, mass gained, feed conversion efficiency, and condition factor also were significantly lower in another group of infected cod of marketable size studied over 12 wk. Xenomas also were observed in the heart and gills of year class II cod reared in a hatchery. Loma branchialis is considered to be a potential pathogen in both hatchery-reared and net pen-cultured cod in Newfoundland.

Animals↗
PubMed2004

Effect, distribution, and prevalence of Glugea stephani (Microspora) in winter flounder (Pleuronectes americanus) living near two pulp and paper mills in Newfoundland.

A study was conducted to determine the effects, geographical distribution, and prevalence of a microsporan parasite, Glugea stephani, in winter flounder (Pleuronectes americanus) in Newfoundland. Fish were captured by SCUBA divers in several coastal areas, including 2 embayments where pulp and paper mill effluent was discharged, as well as a number of pristine sites. Fish health was assessed by comparing histological profiles, condition factors (K), organosomatic indices and blood values between infected and uninfected samples. Multifocal xenomas of G. stephani were observed in several organs of fish taken near contaminated sites, whereas infected samples captured at a pristine site harbored the cysts only in the wall of the digestive tract. Proliferative inflammation, granuloma formation, and focal necrosis were associated with the infection primarily in the liver and kidney. Condition factors and blood values were lower and ovarian development inhibited or delayed in infected flounder. The multifocal infection occurred only in flounder in 2 embayments in western Newfoundland where pulp and paper mill effluent was discharged. Prevalence varied seasonally, with a peak in autumn and a low in spring. It is likely that the multifocal infection was associated with immunodepression after exposure to the contaminant.

Animals↗
PubMed2004

Absorption of non heme iron in typical and standard meals using extrinsically labeled iron 59Fe.

OBJECTIVE: To study the bioavailibility of nonheme iron from standard and test meals in Pakistani adults and to determine iron absorption using extrinsically tagged iron 59Fe. SUBJECTS AND METHODS: Nonheme iron absorption was measured from standard and test meals in ten healthy individuals. Total calories, carbohydrates, proteins, fats, ascorbic acid, total iron, phytate and ascorbic acid content were determined in both meals. Retention of iron was detected by whole body counting using gamma counter before and after administration of standard, test meals and reference dose. RESULTS: Iron absorption with test meal was 13% and after adjustment with serum ferritin and reference dose was 16.5 % and 14% respectively. The absorption of standard meal was 6.7% which after adjustment with serum ferritin and reference dose was 8.8% and 6.9% respectively. The iron and ascorbic acid content of test meal was 6.5 mg and 5.7 mg respectively while phytate phosphorus content was 114 mg. The iron and ascorbic acid content of standard meal was 1.3 mg and 2.4 mg respectively while phytate phosphorus content was 137 mg. CONCLUSION: This evaluated absorption from one of the typical Pakistani diet compared to the standard meal was better. This shows that there are some other physiological factors that lead to iron deficiency anemia in Pakistan.

Absorption↗
PubMed2003

Health of flatfish from localities in Placentia Bay, Newfoundland, contaminated with petroleum and PCBs.

This study compared the health of flatfish inhabiting two areas in Placentia Bay, Newfoundland, contaminated either with polycyclic aromatic hydrocarbons (PAHs) or polychlorinated biphenyls (PCBs) with samples from reference sites. Initially, four species of flatfish, including American plaice (Hippoglossoides platessoides), yellowtail flounder (Limanda ferruginea), gray sole (Glyptocephalus cynoglossus), and winter flounder (Pleuronectes americanus), were sampled only for external lesions from commercial catches at three offshore sites. Others, captured by scuba divers at inshore sites, were autopsied to compare external lesions, condition (K) factor, hepatosomatic index (HSI), hemoglobin and lymphocyte levels, histological changes in the liver and spleen, and two parasites, metacercariae of Cryptocotyle lingua in the skin and a digenetic trematode, Steringophorus furciger, in the digestive tract. A higher prevalence of lesions occurred in the four species of flatfish caught offshore by commercial fisherman near the oil terminal and the PCB-contaminated dockyard than at a reference site. Lesions were also more prevalent in three species of flatfish captured by scuba divers inshore near the oil terminal and were associated with significantly lower K factor and lymphocyte levels but elevated HSI values and histopathological changes in the liver and spleen than in reference samples. Winter flounder sampled at two locations near the PCB-contaminated dockyard and a PAH-polluted small boat wharf also exhibited more external lesions, liver discoloration, and lower K factor, hemoglobin, and lymphocyte but higher HSI values and hepatic and splenic hemosiderosis than in reference fish. Prevalence of C. lingua in the skin was significantly greater but S. furciger in the digestive tract lower in samples taken from the aforementioned contaminated sites than from the reference locations. These results, based on several bioindicators, suggest that the health of bottom-dwelling flatfish at three sites of this embayment was impaired by chronic exposure to sediment contaminated with PAHs or PCBs.

Animals↗
PubMed2003

Chronic stress in cunner, Tautogolabrus adspersus, exposed to municipal and industrial effluents.

Chronic changes were measured in fish downstream from a pulp and paper mill located in the Humber Arm, Newfoundland, Canada. Cunner (Tautogolabrus adspersus) downstream of the mill were longer and heavier at an earlier age than reference fish. Condition factor was similar among sites. Hepatosomatic indices and ethoxyresorufin-O-deethylase activity were higher in fish near the mill. Gondal condition suggested that gametogenesis might have been delayed in these same fish. Although splenosomatic indices were greater in exposed fish, splenic hemosiderin was not significantly different from reference values. Gill and liver changes in exposed cunner were significant. Gill parasites showed no site difference; however, the prevalence and abundance of gastrointestinal acanthocephalans were significantly greater in fish from impact sites. These results suggest that effluent from this mill may be responsible for observed biological effects; however, further study is needed to determine whether gradients in nutrient loading and untreated sewage discharge may also contribute to fish health in the Humber Arm.

Animals↗
PubMed2003

An epidemiological study on prevalence of endemic goitre among the people of two goitre endemic areas of Bangladesh.

This was a retrospective type of cross section study to find out the prevalence of endemic Goitre among the people of the two unions of Dewangonj Upazilla of Jamalpur district. A total of 375 respondents were included in the study. The result of the study showed that maximum (29.06%) number of the respondents was in age group 41-50 years. Out of 375 respondents 56.80% was female and 43.20% were male. Maximum (52.53%) respondents were illiterate. 47.47% were house wives, 20% cultivators, 11.73% students, 8.27% businessmen, 7.73% service holder and 4.8% labour. Majority (56.80%) respondents were poor, 28.50% were middle class, 7.73% were very poor and 6.67% were rich. Cent percent of the respondents drink tube-well water. Majority (78.6%) of respondents consumed iodized salt and 21.33% did not consume iodized salt. Regarding the cause of non-using iodized salt 90% respondents mentioned high cost of iodized salt and 10% respondents mentioned their ignorance.

Adult↗
PubMed2003

Factors affecting the early discharge of the indoor psychotic patients - a sociodemographic survey in a specialized institution.

This is descriptive type of cross-sectional study carried out among 100-discharged patient in a specialized psychiatric hospital. Socio-demographic study revealed that among 100 cases 97% were admitted with schizophrenia, 35% with bipolar affective disorder, 10% with psychotic depression, 5% with brief psychotic disorder, 2% with schizoaffective disorder, 1% with schizophreniform disorder. Their mean hospital stay was 19 days with highest mean hospital stay in schizoaffective disorder (32 days). Mean age of the patient was 26.5 years and highest no. of patients (52%) were in 20-25 years age group. Male female ratio of the patient was 3.761: 1. Occupational distribution of the cases family history of psychiatric illness in 1st degree and 2nd degree relatives was present and mean duration of illness was 73.4 months. Statistically significant independent variables that have impact on length of hospital stay (Dependent patient (p<0.007); electro convulsive therapy (p<0.005); family history of psychiatric illness (p< 0.046), Treatment with typical antipsychotic drugs (p <0.033); treatment with atypical antipsychotic drugs (p <0.000), Rx with combination of typical and atypical antipsychotic drugs (p<0.012); treatment with depot preparation (p<0.011); Treatment with combination of oral antipsychotic drugs (p<0.003) and patient hailing from rural area (p<0.026).

Adolescent↗
PubMed2002

Some factors influencing EROD activity in winter flounder (Pleuronectes americanus) exposed to effluent from a pulp and paper mill.

EROD (ethoxyresorufin-O-deethylase) activity was determined in winter flounder, a sediment-inhabiting and non-migratory fish species, living near a pulp and paper mill in Newfoundland in relation to temperature, gender, sexual maturity, and lesions in the liver. Samples of liver were taken from fish captured by SCUBA divers at 0 degrees C, 5 degrees C and 16 degrees C. Enzymic activity was detected in fish living only above 0 degrees C. Adult males and juvenile fish had higher levels of EROD activity than prespawning females at 5 degrees C. Macrophage aggregates only or occurring simultaneously with bile ductule hyperplasia and clear cell foci in the liver, did not impair EROD activity but necrosis had a negative effect. Results from this study indicate the importance of water temperature, gender, sexual maturity and liver pathology in assessing EROD activity of fish in biomonitoring programs.

Animals↗