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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
PubMed1992

Progressive myoclonic ataxia without ragged red fibres: Unverricht-Lundborg disease vs Ramsay Hunt syndrome.

We describe eight patients from three families presenting with myoclonus, ataxia, infrequent seizures and minimal intellectual impairment. All were Arabs from different parts of the Arabian peninsula. The new consensus on terminology, genetic and clinical definition of Baltic myoclonus, Ramsay Hunt syndrome and Unverricht-Lundborg disease suggests that our group are best categorised under the term of progressive myoclonic ataxia of the Unverricht-Lundborg type. Moreover, this report reinforces the existence of this syndrome outside Scandinavia.

Adolescent↗
PubMed1992

Prevalence of Trichinella spiralis in black bears (Ursus americanus) from Newfoundland and Labrador, Canada.

Tongue and diaphragm samples from 158 black bears (Ursus americanus) from Newfoundland and Labrador were examined for Trichinella spiralis. No larvae were detected in samples from the island of Newfoundland but one animal from the Labrador samples was infected. The results of this and other studies suggest a lack of involvement of the black bear in a sylvatic cycle of T. spiralis in eastern Canada.

Animals↗
PubMed1992

Iron deficiency in adolescents.

Two hundred and seventy school children between 13 to 20 years were investigated for iron deficiency. Overall iron deficiency (assessed by serum ferritin assay) was 39% in adolescents; 30% boys and 54% girls were iron depleted, anemia was found in 17% boys (Hb 13g/dl) and in 18% girls (Hb 12g/dl). Iron deficiency was more frequent than anemia in adolescent girls than boys. Iron deficient children had significantly lower mean Hb levels (p 0.001) compared to children with adequate iron stores. A significant correlation was found between serum ferritin concentration and Hb levels in iron deficient children (r = 0.49, p 0.001). A high prevalence of iron deficiency in adolescents reported here reflects the limited availability of dietary iron in children belonging to lower socio-economic group and the importance of screening for iron deficiency and the treatment of these children with iron preparation. Iron status in this age group warrants further evaluation and research.

Adolescent↗
PubMed1991

Influence of pollution on parasites of aquatic animals.

We have tried to draw attention to an increasing body of evidence (from several publications) that parasites of fish might be useful indicators of pollution. Several types of pollutants, including domestic sewage, pesticides, polychlorinated biphenyls, heavy metals, pulp and paper effluents, petroleum aromatic hydrocarbons, acid rain, and others, are known to affect aquatic animals. Many of the latter are parasitized and, under natural environmental conditions, most fish parasites are believed to cause little or no harm. However, chronic exposure to pollutants over a period of time causes biochemical, physiological and behavioural host changes that ultimately can influence the prevalence and intensity of parasitism. Some of these changes include host nutrition, growth and reproduction. Macroscopic lesions might not always be apparent, but subtle disorders in several specific tissues and organs might occur. Pollutants might promote increased parasitism in aquatic animals, especially fish, by impairing the host's immune response or favouring the survival and reproduction of the intermediate hosts. Alternatively, decreased parasitism might ensue through toxicity of the pollutant to free-living stages and intermediate hosts or by alteration of the host's physiology. Experimental studies indicate that the numbers of ectoparasites such as trichodinid ciliates and monogeneans increase significantly on the gills following exposure to a pollutant, and this is supported by field data on other ciliates and monogeneans where evidence of pollution has been clearly demonstrated. There is also evidence that endoparasitic protozoons, such as myxozoons, microsporans and haematozoons, all of which are capable of proliferating in their hosts, increase substantially in prevalence and intensity when interacting with pollutants. The period of patency might also be prolonged in haematozoan infections. Most reports of pollution effects on endoparasites suggest increased parasitism in fish hosts. This also applies to fish living in areas which receive thermal effluents. Parasites might in turn enhance their hosts' susceptibility to pollutants, and information in support of this view is accumulating. Finally, immunosuppression represents one of the underlying mechanisms influencing increased parasitism. Thus, while published information suggests more than a casual connection between fish parasites and pollution, further research is needed to establish the cause-and-effect relationship and at the same time take cognizance of histopathological effects of the toxic agents and their concentrations in water. Areas for future research are recommended.

Animals↗
PubMed1991

Mortality in Atlantic salmon (Salmo salar) associated with trichodinid ciliates.

A protozoan infection (Trichodina truttae) was identified in captive Atlantic salmon (Salmo salar) kelts that died in spring of 1988 and 1989. Fish with intense infections showed signs of listlessness, erratic swimming and inappetence. The infection induced excessive mucus secretion, epithelial sloughing and lesions that probably permitted entry of opportunistic bacteria which eventually caused ulcers and death. A seawater bath for 30 min each week for 4 wk effectively controlled the parasite.

Animals↗
PubMed1991

Sarcocystis in caribou (Rangifer tarandus terraenorae) in Newfoundland.

Prevalence of species of Sarcocystis in muscle of 36 caribou, Rangifer tarandus terraenorae, shot in Newfoundland, Canada, was 53%. A greater percentage of infected animals were obtained from the central part of the island. The highest concentration of microscopic sarcocysts, 1/mm2 of tissue, was observed in a 5-year old animal. Although widely distributed throughout the body, cysts were more prevalent in the tongue and diaphragm. The potential of Sarcocystis in caribou as a food-borne disease organism in man cannot be overlooked in view of its prevalence in meat and its widespread consumption, when lightly cooked, in rural Newfoundland.

Animals↗
PubMed1991

Influence of pollution on parasites of aquatic animals.

This workshop draws attention to an increasing body of evidence which supports the view that parasites of aquatic animals are influenced by pollution. Pollutants might promote increased parasitism by impairing the host's immune response or favouring survival and reproduction of intermediate hosts. Decreased parasitism might occur because of toxicity to free-living stages, intermediate hosts or alteration of the host's physiology. Prevalence and intensity of ectoparasites in conjunction with histopathology and concentration of xenobiotics in both fish and parasites appear to be a promising approach. Future research on the interaction of pollution on parasites of animals should focus on a combination of field and laboratory studies, especially exposing fish in cages to polluted water.

Animals↗
PubMed1991

Differentiation of cirrhotic Vs idiopathic portal hypertension using 99mTc-Sn colloid dynamic and static scintigraphy.

Thirty-seven cases of portal hypertension with endoscopically proven oesophageal varices underwent liver biopsy to determine the etiology of portal hypertension. Of the total, 19 had cirrhosis and 18 idiopathic portal hypertension (IPH). Later all these patients underwent Tc99mSn colloid, static and dynamic scintigraphy of the liver and spleen. Ratios of the area and of the integral and slope of the integral for liver and spleen were calculated to see if any of these ratios can differentiate cirrhotics from IPH. Significant difference (P less than 0.001) was noted in the ratio of the area (L/S) in both patients and controls, but the ratios of the integral and the slope of the integral were not only significantly different (P less than 0.001) in the patients and controls but also in the two groups of patients (cirrhosis and IPH). The sensitivity of this test when compared with the histology was 58% for both cirrhosis and IPH but when compared with clinical diagnosis it was 76% for cirrhosis and 62% for idiopathic group. Therefore by adding the above mentioned test in the routine study of liver scintigraphy in patients with portal hypertension, further differentiation of cirrhotic group can be done from the idiopathic group.

Adolescent↗
PubMed1990

Brainstem auditory evoked potentials in Wilson's disease.

Twelve patients with Wilson's disease, aged 11-25 years, underwent brainstem auditory evoked potential (BAEP) study. The results were correlated to clinical, neuroradiological and laboratory data. Ten had prominent to severe neurological manifestations, suggestive of involvement of one or several CNS structures, and 2 were neurologically free. All had evidence of abnormal copper metabolism, and 8 had CT scan evidence of brain atrophy, or hypodense areas in basal ganglia, or both. The 2 patients without neurological manifestations as well as one with neurological signs had normal BAEP. One patient with neurological signs had increased N1 latency due to cochlear hearing loss, but normal interpeak intervals, while 8 of 10 patients with prominent neurological symptoms and signs had abnormal BAEPs (prolongation of NIII-NV interpeak interval). The value of NIII-NV interpeak interval correlated with the number of different neurological signs (neurological score) attributable to involvement of different CNS structures (r = 0.64 at P = 0.001). Abnormal BAEPs do not seem to be an early finding in Wilson's disease.

Adolescent↗
PubMed1990

Lernaeocera branchialis: a potential pathogen to cod ranching.

A study was carried out to determine the effect of Lernaeocera branchialis on Atlantic cod infected in the laboratory and in the field and also to ascertain its effect on cod-ranching. Sixty-four percent (308) of 481 cod acquired infections in the laboratory and 33% (159) of the infected fish died over a 4-yr period. About 74% of the deaths occurred within 4 mo of the infection. Monthly samples of cod collected adjacent to a cod-ranching operation showed an initial prevalence of 30% that subsequently decreased in the following 2 mo to 15%. Prevalence of the infection also decreased among the initial field sample of cod that were kept alive, from 30 to 17% during the same 2-mo period and to 9% after 8 mo and was associated with death caused by the parasite. Cod examined at intervals after infection showed evidence of reduced weight gain, lower liver somatic index, liver lipid, and blood values than controls. A field sample taken from the same area during the summer of the following year indicated a prevalence of 12%. This higher than usual prevalence (4-6%) was associated with retention of the intermediate host, Cyclopterus lumpus, that provided an additional source of infective stages. It is likely that increased parasitism could affect the success of the cod-ranching operation in view of the parasite's devastating effects on its hosts.

Animals↗
PubMed1990

Myxozoa of deep-sea fishes in the northwestern Atlantic.

The gall bladder of 5 species of deep-water fishes (Coryphaenoides armatus, Coryphaenoides rupestris, Macrourus berglax, Antimora rostrata, and Synaphobranchus kaupi) from the New York Bight and Carson Canyon areas in the northwest Atlantic were examined for myxozoan parasites. Myxidium coryphaenoidium was found in 4 fish species, whereas Auerbachia pulchra and Ceratomyxa sp. were each observed in 1 fish species. Prevalence of myxozoan infections was greater in fishes taken off the New York Bight than from the Carson Canyon.

Animals↗
PubMed1989

Ferritin levels in professional blood donors.

Iron stores were estimated in 333 professional blood donors by serum ferritin assay. Iron deficiency or depleted iron stores assessed by low serum ferritin levels (less than 12ng/ml) were found in 15% donors. In 51% donors the serum ferritin was within the normal range, while 34% donors had high serum ferritin levels (above 200 and upto 3580 ng/ml). Anaemia (Hb less than 13g/d1) was found in 284 (85%) donors, 51 (18%) of these had iron deficiency or low ferritin levels, 99 (35%) had high and 134 (47%) had normal serum ferritin levels. Iron deficiency in blood donors could be associated with repeated blood donations. High serum ferritin levels could be due to reasons like taking of medicinal iron much beyond the recommended dosage by self initiation. Therefore, estimation of serum ferritin has no value in professional blood donors.

Adult↗
PubMed1989

Serum thyroid hormone levels in liver cirrhosis.

Levels of thyroid hormones, serum thyroxine, triiodothyronine (T3), free thyroxine (FT4), free triiodothyronine (FT3) and thyrotropin (TSH) were measured in 55 patients with liver cirrhosis using radioimmunoassay techniques. Results were compared with 78 controls. The mean serum concentration of T3, FT3 and FT4 were significantly decreased in cirrhotics, while no significant change was noted in serum T4 and TSH levels. T3/T4 ratio was also lower than the normal. This indicates an impaired liver conversion of T4 to T3 in peripheral tissues. Serum T3 and FT3 showed an inverse correlation with serum bilirubin and a positive correlation with serum albumin. T3, FT3 and T3/T4 ratios were significantly low in patients who had ascites as compared to those who had no ascites. This study confirms the presence of abnormalities in serum thyroid hormone levels in cirrhosis of liver. Alteration in serum T3 and FT3 levels correlate well with the disease severity and may be useful in assessing the course and prognosis in cirrhotic patients.

Adolescent↗