Biomedical subjects
M Husain
Publications and source records attributed to M Husain.
Arachnoid cyst with type I Arnold Chiari malformation presenting as syringomyelic syndrome.
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Cervical squamous cell carcinoma and its precursor lesions: cytodiagnostic criteria and pitfalls.
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Malignant melanoma of soft parts diagnosed by needle aspiration cytology and electron microscopy.
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Detection of group A rotavirus by reverse transcriptase and polymerase chain reaction in feces from children with acute gastroenteritis.
RT-PCR was employed to detect rotavirus infection in 450 fecal samples from children with acute diarrhoea. It was compared with enzyme-linked immunosorbent assay (ELISA) and polyacrylamide gel electrophoresis (PAGE) for rotavirus detection. A total of 67 samples were found positive by at least one of the three techniques. Of these 67 samples, 51 were positive by all three methods, 6 were positive by ELISA and RT-PCR but negative by PAGE, 3 were positive by PAGE and RT-PCR and negative by ELISA, 3 and 4 samples were exclusively positive by RT-PCR and ELISA respectively. These results indicate that RT-PCR is a sensitive and specific assay for detection of group A rotaviruses in stool samples from cases of acute diarrhoea.
Mesopontine neurons in schizophrenia.
Findings reported here show that there is a significant increase in the number of neurons in the pedunculopontine nucleus in most schizophrenic patients compared to age-matched controls. Nicotinamide adenine dinucleotide phosphate diaphorase histochemistry was used to label putative cholinergic neurons in the pedunculopontine nucleus and laterodorsal tegmental nucleus, while noradrenergic locus coeruleus neurons were labeled immunocytochemically using an antibody to tryosine hydroxylase. Cell counts of these neuronal groups were carried out using a Biographics image analysis system. We found significantly increased cell numbers in the pedunculopontine nucleus of schizophrenic patients compared to controls. The number of laterodorsal tegmental nucleus neurons was increased but this was not statistically significant. However, the total cell counts for pedunculopontine and laterodorsal tegmental nuclei were significantly higher in schizophrenic subjects. The number of locus coeruleus noradrenergic neurons was similar in both groups. These results implicate the brainstem reticular formation as a pathophysiological site in at least some patients with schizophrenia. In addition, these findings suggest a developmental etiology for the disease and account for some, but not all, of the symptoms of schizophrenia, including sensory gating abnormalities, sleep-wake disturbances and, perhaps, hallucinations. Overdriving of thalamic and substantia nigra function by cholinergic afferents from the midbrain may account for some of the symptoms seen in schizophrenia. These findings suggest that, at least in some schizophrenic patients, there is an increased number of neurons in the cholinergic arm of the reticular activating system. This may explain some of the symptoms of schizophrenia and points to a prenatal disturbance as one of the possible causes of the disease.
Direct detection and characterization of rotavirus into subgroups by dot blot hybridization and correlation with 'long' and 'short' electropherotypes.
BACKGROUND: Enzyme-linked immunosorbent assay (ELISA) and polyacrylamide gel electrophoresis (PAGE) of viral RNA are well-established methods for detection of rotavirus in stool samples. Dot-blot hybridization has also been found to be a sensitive and specific technique for detection and characterization of rotaviruses. OBJECTIVES: To compare the performance of dot blot hybridization with ELISA and PAGE for detection of rotavirus in stool samples. To assess the use of dot blot hybridization for characterization of rotaviruses into subgroups. STUDY DESIGN: Stool samples were collected from 214 children presenting to the hospital with acute diarrhoea. These were assayed for rotavirus by ELISA and PAGE. Dot-blot hybridization was done with full length cloned radiolabelled c-DNA probes of gene segment 6 of SA-11 (subgroup I) and Wa (subgroup II) rotaviruses. RESULTS: Out of 214 stool samples 134 were found to be positive for rotavirus by one of the three methods. Among these 134 positive specimens 114 were positive by dot blot hybridization, this included 18 specimens which were positive only by dot blot assay. One-hundred-and-twelve of these 114 specimens could be subgrouped. Fifteen of these were classified as subgroup I, 97 as subgroup II and two had a dual subgroup specificity. Three subgroup 1 strains had a 'long' RNA pattern, whereas one subgroup II strain had a 'short' RNA pattern which has not been reported earlier for human rotaviruses. CONCLUSION: Dot blot hybridization as described here is a sensitive and specific assay for detection and subgrouping of rotaviruses. However, as there is a considerable genomic diversity among rotaviruses, the panel should include probes from all the genotypes of gene segment 6.
Neuro-ophthalmology of degenerative neurological disorders.
A number of degenerative disorders of the nervous system are associated with visual or ocular motor disturbances. Over recent years, these problems have attracted a great deal of interest because they may aid diagnosis and also improve our understanding of pathophysiology. In this review, we discuss both of these aspects of the study of degenerative conditions and attempt to demonstrate the clinical significance of a number of new findings.
Lipoprotein(a) and apolipoproteins B and A-I after acute myocardial infarction.
OBJECTIVE: To assess the temporal behaviour of plasma lipoprotein(a) [Lp(a)]--a low density lipoprotein-like particle whose plasma levels are associated with atherosclerosis risk--and apolipoproteins (apo) B and A-I (the major protein components of low and high density lipoproteins, respectively) in acute myocardial infarction (AMI), and to determined the effect of tissue plasminogen activator (tPA) on them. DESIGN AND PATIENTS: Serial Lp(a), apoB and apoA-I determinations were obtained over eight days in 19 AMI patients who were part of a randomized, placebo (n = 7) controlled trial of tPA (n = 12). MAIN RESULTS: At 48 h postinfarct, plasma Lp(a) and apoB concentrations were, respectively, 20% (24.9 +/- 3.0 to 19.9 +/- 2.9 mg/dL, P < 0.05) and 28% (1.37 +/- 0.10 to 0.99 +/- 0.11 mM/L, P < 0.05) below baseline values. ApoA-I concentrations were unchanged at 48 h postinfarct. At 192 h postinfarct, Lp(a) rebounded to 36% above baseline (24.9 +/- 3.0 to 33.9 +/- 3.9 mg/dL, P < 0.05), apoB returned to baseline (1.37 +/- 0.10 versus 1.33 +/- 0.11 g/L, P < 0.05) and apoA-I was 15% below baseline (1.43 +/- 0.06 to 1.21 +/- 0.06 g/L, not significant). Administration of tPA had no effect on any of these changes. CONCLUSIONS: Plasma Lp(a) and apolipoproteins undergo shifts from baseline values in the postinfarct period and tPA has no effect on these variations.
Chromosome aberrations in four ependymomas.
Cytogenetic analysis of short-term cultures from three untreated and one recurrent ependymoma revealed clonal aberrations in three of the four tumors. A posterior fossa ependymoma from a 3-year-old male patient showed trisomy 11 as the sole clonal chromosome aberration. A recurrent spinal ependymoma from a 35-year-old male showed hypertriploid clones with abnormalities involving chromosomes 1p11,7q21, and 10p13. A 62-year-old male patient with a cerebellar ependymoma showed a hypodiploid stem-cell line with clonal structural aberrations of both the long and short arms of chromosome 1, an interstitial deletion of 2q, trisomy 7, and monosomy for chromosomes 11, 13, and 16. A 3-year-old female patient with posterior fossa ependymoma showed a normal 46,XX karyotype. Chromosome 1 aberrations appear to be the most consistent finding in this small series of tumors, with the net loss or rearrangement of chromosome 1 pter-->p22 material from two of the four tumors. These findings, in addition to a previously published case [1], suggest a possible role for genes on the short arm of chromosome 1 in the cytogenetic evaluation of ependymomas.
Neonatal primary hyperparathyroidism masked by vitamin D deficiency.
Neonatal primary hyperparathyroidism is a life threatening disorder that is associated with severe hypercalcaemia, hypotonia, bone demineralization, fractures and respiratory distress. Treatment consists of total parathyroidectomy and without this affected infants will usually die by the age of three months. We report a patient with neonatal primary hyperparathyroidism who survived without fractures or parathyroidectomy to an age of nine months, and in whom the hypercalcaemia became masked by vitamin D deficiency. At surgery, four-gland hyperplasia was demonstrated and total parathyroidectomy followed by oral calcitriol treatment has restored well-being and normocalcaemia. An absence of skeletal complications, a survival beyond three months of age without parathyroidectomy and the masking of the hypercalcaemia by vitamin D deficiency represents a unique combination of metabolic abnormalities in a patient with neonatal primary hyperparathyroidism.
Visually and memory guided saccades in a case of cerebellar saccadic dysmetria.
Saccades under four specific test conditions (visually guided, visually remembered, vestibular remembered, and cervical remembered) were studied in a 38 year old man with ocular dysmetria due to an angioma of the dorsal cerebellar vermis. The aim of the study was to investigate if the saccadic disorder was specific to certain subsets of saccades elicited by different sensory modalities. The experiments showed that initial saccades were equally hypermetric in all four conditions and that final eye position was normal in all memory guided saccade tests. Eye movements differed after the initial saccade, however. Whereas corrective saccades were seen in most visually guided and visually remembered experiments, postsaccadic centripetal drifts were documented in non-visual (vestibular and cervical) remembered saccades. These results indicate that the cerebellar vermis modulates the amplitude of the initial saccade (pulse size of saccadic innervation) independently of the saccadic task. The finding that post-saccadic drift never occurred when saccades were programmed using visual positional information suggests that the dorsal vermis may participate in the process of pulse step integration of saccades elicited by memorised vestibulo-cervical information.
Exhaled nitric oxide as a marker for organic nitrate tolerance.
BACKGROUND: This study was designed to demonstrate the development of biochemical tolerance to organic nitrates by measuring levels of exhaled gaseous nitric oxide (NO) in lambs given intravenous (IV) nitroglycerin or sodium nitroprusside. METHODS AND RESULTS: IV injections of nitroglycerin or sodium nitroprusside produced dose-dependent and sustained increases in the exhaled levels of nitric oxide measured by chemiluminescence in awake lambs with tracheostomies. After a 6-hour IV infusion of 25 micrograms.kg-1.min-1 nitroglycerin, peak exhaled NO levels were significantly reduced (-53.6 +/- 4.9%, mean +/- SEM, P < .001) and systemic hypotensive responses were attenuated (-52.6 +/- 5.9%, P < .001) after an IV challenge of nitroglycerin but not sodium nitroprusside. After a subsequent 12-hour nitroglycerin-free period, there was complete recovery of NO excretion in exhaled breath and a return to baseline of systemic hypotensive changes on administration of IV nitroglycerin boluses. For IV sodium nitroprusside challenges, pulmonary NO excretion and systemic hypotensive responses remained constant throughout the study. Challenges with IV nitroglycerin but not sodium nitroprusside during a 12-hour nitroglycerin-free period resulted in delayed biochemical recovery with various exhaled NO levels and systemic hypotensive responses to challenges with IV nitroglycerin. CONCLUSIONS: Measurements of exhaled NO provide in vivo, noninvasive evidence for the development of biochemical tolerance to nitroglycerin. There was reduced NO release into exhaled gas from the pulmonary vasculature concomitant with evidence of tolerance to nitroglycerin vasodilation in the systemic circulation.
Ring chromosome 12 resulting from nonrandom telomeric associations with the short arm of chromosome 15 in a cerebellar astrocytoma.
Ring chromosome 12 was found in an untreated cerebellar astrocytoma apparently resulting from nonrandom telomeric associations involving the short arm of chromosome 15, and both the long and short arms of chromosome 12. The clonal nonrandom telomeric associations of 15p to both ends of the chromosome 12 were transitory, but appear to be the precursor lesion in the evolution to ring chromosome 12 in this tumor. A multistep process in the formation of a ring chromosome resulting from nonrandom telomeric associations to both telomeres is illustrated.
Neuroanatomical substrates of depression in the elderly.
The etiology of depression in the elderly is poorly understood. In this study, magnetic resonance imaging was used to evaluate the role of subcortical structures in the pathophysiology of depression in the elderly. Elderly depressed patients were found to have smaller caudate nuclei, smaller putaminal complexes and in increased frequency of subcortical hyperintensities compared with normal, healthy controls. These findings were more pronounced in patients with late-onset depression. Based on these findings, the authors discuss the role of the basal ganglia in the pathophysiology of depression in the elderly.
Comparison of seroepidemiology of hepatitis C in blood donors between Bangladesh and Japan.
To compare the seroepidemiology of hepatitis C and hepatitis B between Bangladesh and Japan, we tested the second generation antibody to hepatitis C virus (anti-HCV-2) and hepatitis B surface antigen (HBsAg) in serum samples from 163 professional blood donors (161 males and 2 females, mean age 28.6 yr.) and 83 voluntary blood donors from Bangladesh, and 7479 Japanese voluntary blood donors (5036 males and 2443 females; mean age 37.1 yr.). In Bangladesh, anti-HCV-2 is detected in 2.4% of professional blood donors and 0% of voluntary blood donors, furthermore, HBsAg is detected in 29% and in 2.4% of professional and voluntary blood donors, respectively. In Japan, anti-HCV-2 is detected in 0.6% in voluntary blood donors, and HBsAg also in 0.6%. These results indicate that professional blood donors in Bangladesh are highly contaminated by hepatitis B virus and moderately by hepatitis C virus, while voluntary blood donors in both countries are not so highly contaminated by either hepatitis viruses.