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Biomedical subjects

N Islam

Publications and source records attributed to N Islam.

At least 55 records · Page 3Linked to original sources
PubMed1995

Induction of depersonalization by the serotonin agonist meta-chlorophenylpiperazine.

Sixty-seven subjects, including normal volunteers and patients with obsessive-compulsive disorder, social phobia, and borderline personality disorder, received ratings of depersonalization after double-blind, placebo-controlled challenges with the partial serotonin agonist meta-chlorophenylpiperazine (m-CPP). Challenge with m-CPP induced depersonalization significantly more than did placebo. Subjects who became depersonalized did not differ in age, sex, or diagnosis from those who did not experience depersonalization. There was a significant correlation between the induction of depersonalization and increase in panic, but not nervousness, anxiety, sadness, depression, or drowsiness. This report suggests that serotonergic dysregulation may in part underlie depersonalization.

Adult↗
PubMed1995

Increase in the calcium level following anodal polarization in the rat brain.

The accumulation of calcium ions (Ca) was examined in the rat brain by means of 45Ca autoradiography following the application of a weak anodal direct current to the surface of the sensorimotor cortex. Repetition of the anodal polarization with 3.0 microA for 30 min caused more Ca to accumulate in the cerebral cortex. The degree and extent of accumulation was greater in the hemisphere ipsilateral to the polarization than in the other. Accumulation was also noted in the hippocampus and thalamus. Ca accumulation was detected after 24 h and it remained virtually constant up to 72 h after the last polarization. The results suggest that a long-lasting disturbance of Ca homeostasis is involved in the cortical plastic changes seen following anodal polarization.

Animals↗
PubMed1995

Detection of DNA damage induced by apoptosis in the rat brain following incomplete ischemia.

To clarify the pathogenesis and molecular basis of ischemia-related nerve cell death, we examined the occurrence of DNA fragmentation as a hallmark of apoptotic cell death following incomplete ischemia in the rat brain by means of in situ end labeling of fragmented DNA. Incomplete ischemia was produced by permanently occluding one carotid artery, while temporarily occluding the other. The condensed nuclei of ischemic neurons in the neocortex, and in the subiculum and CA1 area of the hippocampus were positively stained 24 h and 3 days following vessel occlusion, respectively, and their morphology was typically apoptotic. The ischemic neurons with condensed nuclei gradually increased in number and were clearly stained for fragmented DNA in these areas. The labeled nuclei in the neocortex became pyknotic 72 h later, and in the hippocampus 7 days later incomplete ischemia. After attaining a peak, the number of labeled nuclei decreased with the duration of recovery in all areas. These results suggest that an apoptotic process plays, at least primarily, a role in the degeneration of neurons associated with incomplete forebrain ischemia in rat.

Animals↗
PubMed1995

c-Fos expression mediated by N-methyl-D-aspartate receptors following anodal polarization in the rat brain.

c-Fos protein-like immunoreactivity (IR) was investigated in the rat brain following an application of weak anodal direct current to the surface of the unilateral sensorimotor cortex in an attempt to elucidate the cellular and molecular bases of central plasticity. Anodal polarization resulted in a massive increase in c-Fos protein-like IR in neurons of the cingulate, piriform, frontoparietal cortices, and hippocampus ipsilateral to the polarization. The effects were dependent upon the duration and intensity of currents applied. The time-dependent induction of c-Fos protein-like IR was maximal at 1 h, became weaker by 6 h, and almost returned to the baseline within 24 h following polarization. When MK-801 [(+)-5-methyl-10,11-di-hydro-5H- dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate], a noncompetitive antagonist for N-methyl-D-aspartate (NMDA) receptors, was injected intraperitoneally, the induction of this nuclear protein was reduced or completely blocked in both hemispheres, except around the polarized point itself, as a function of the time and dosage. These results suggest that the proto-oncogene c-fos is rapidly and transiently activated in the brain following anodal polarization and this activation is mediated by NMDA receptors.

Animals↗
PubMed1995

Formation of thymine-lysine and cytosine-lysine adducts in DNA-lysine photoconjugate.

Lysine was covalently conjugated to calf thymus DNA by irradiation with UV light (wavelength, 253.7 nm). The results showed monofunctional covalent photobinding of lysine molecules with bases in DNA. Only the epsilon-amino group of lysine participated in the photoconjugation reaction. Thymine and cytosine were modified by 60% and 25% respectively. The kinetics of the DNA-lysine photoreaction showed that one lysine molecule was in the photobound state per 10, 6, 5 and 4 nucleotide base pairs of DNA on irradiation for 20, 30 40 and 60 min respectively.

Animals↗
PubMed1995

Management of isolated radial or ulnar arteries at the forearm.

The effects of management of single forearm arterial injuries without other associated major muscular, vascular, or neurological trauma were studied. Ninety-six patients with acute injuries to either radial or ulnar arteries without obvious associated major injuries were evaluated. No patient had an ischemic hand secondary to arterial injury. The selection of operative treatment by arterial repair or ligation was by surgeon choice (50 injuries were ligated, and 46 were repaired). Six months to six years postoperative follow-up was done. The overall patency rate for all repaired vessels was 52% (24 cases). The collateral arteries appeared to be a factor causing the low patency rate. The remaining intact artery demonstrated a consistent increase in flow velocity. No subject had hand claudication; there were 51 cases (53%) of hand weakness, 27 incidents (28%) of parasthesia, and 14 incidents (15%) of cold sensitivity independent of patency of the damaged forearm vessel. In the absence of acute hand ischemia, ligation of a lacerated radial or ulnar artery is safe and cost effective.

Adolescent↗
PubMed1995

Effect of concurrent feeding of furazolidone and sodium chloride upon some clinical, pathological and cardiac morphometric parameters in broiler chicks.

Broiler chicks in different groups were fed furazolidone (0, 400 and 800 mg/kg feed) and sodium chloride (500 and 1510 mg/kg feed) separately and concurrently from 1 to 30 days of age. Furazolidone (Fz) induced ascites, leg weakness, convulsions, depression and mortality was exacerbated by concurrent feeding of 1510 mg NaCl. Hemorrhages in the liver, swollen kidneys, pallor of the kidneys and cystic testes were present in all birds fed furazolidone either alone or in combination with NaCl. However, at microscopic level, necrotic changes were observed in the liver and kidneys of birds fed NaCl only. Fz-induced cardiac ventricular dilatation and thinning of walls were more severe when 400 mg Fz was fed concurrently with 1510 mg NaCl but feeding of 800 mg Fz with the same level of NaCl resulted in partial amelioration of cardiac changes. It is suggested that high dietary NaCl may exacerbate and alter the clinical and morphological picture of Fz toxicosis.

Animals↗
PubMed1995

Induction of Fos expression following anodal polarization in rat brain.

Expression of c-fos immunoreactivity was investigated in rat brain after unilateral application of a weak anodal direct current (anodal polarization) to the sensorimotor cortex of rats. Increases in Fosimmunopositive neurons were observed transiently in the neocortex, cingulate cortex, piriform cortex, and hippocampal formation, which were ipsilateral to the polarization, as a function of the duration and intensity of the current applied. It is likely that anodal polarization enhances the neuronal activities in the cortex dependent on polarization paradigms.

Animals↗
PubMed1995

Unusual complications in benign tertian malaria.

An unusual case of malaria with Plasmodium vivax is reported which had complications classically seen with Plasmodium falciparum malaria. The complications were cerebral malaria, disseminated intravascular coagulation and adult respiratory distress syndrome.

Adult↗
PubMed1995

Experimental furazolidone toxicosis in broiler chicks: effect of dosage, duration and age upon clinical signs and some blood parameters.

Groups of broiler chicks of one day and three weeks of age were given feeds containing 0, 400, 800 and 1000 mg furazolidone (Fz)/kg for three weeks. The age of the birds and the dose and duration of Fz treatment significantly (P < or = 0.05) influenced the parameters studied. Clinical signs of Fz toxicosis included ascites, leg weakness and nervous derangement like convulsions and torticollis. The body weight also decreased. Ascites and nervous derangement was not observed in birds fed 400 mg Fz from one day of age. Fz-fed birds developed anaemia and had lower plasma total protein and albumin levels than those fed no Fz. The decrease in body weight was related to reduced feed intake. Decreases found in the haematological parameters and plasma proteins showed no correlation with the chicks' age but were related to the dose and duration of Fz treatment.

Anemia↗
PubMed1995

Immunocytochemical distribution of gamma isoform of protein kinase C (PKC-gamma) following incomplete ischaemia.

Immunocytochemical distribution of PKC-gamma was examined in rat brain in relation to molecular mechanisms of post-ischaemic neuronal modulation following incomplete ischaemia. Incomplete ischaemia was developed by either permanent occlusion of one common carotid artery (CA) or permanent occlusion of one CA with temporary occlusion of opposite CA. Unilateral CA (UCA) occlusion resulted in a pronounced increase in the intensity of staining and number of PKC-gamma positive neurons in the neocortex ipsilateral to the insult after 3 h. The effect was maximum at 6-12 h and was undetectable after 7 days. CA1 neurons showed an increase immunoreactivity (IR) after 1 day, reached to a peak by 3 days, then reduced to basal levels after 7 days. Bilateral CA (BCA) occlusion showed almost similar changes in the neocortex, but on both sides and short durated. The altered patterns of PKC-gamma IR in the neocortex and hippocampus following CA occlusion may reflect activation and/or down-regulation of PKC-gamma in ischaemic neurons. PKC-gamma may, therefore, potentially play an important role in the post-ischaemic modulation of synaptic efficacy in these neurons and in the neuronal damage following incomplete ischaemia.

Animals↗
PubMed1995

Furazolidone toxicosis in young broiler chicks: morphometric and pathological observations on heart and testes.

Broiler chicks 1 d and 3 w of age were given 0, 400, 800, or 1000 mg furazolidone (Fz)/kg feed for 4 w. Bi-ventricular heart dilatation (as measured by increases in ventricular diameter and thinning of the ventricular walls) was present in 1-d-old chicks fed 800 mg Fz, whereas in 3-w-old groups these changes occurred at 1000 mg Fz. There was no heart hypertrophy. Microscopic changes in the heart were not discernible in and Fz-fed birds. The liver had congestion and cytoplasmic vacuolation of hepatocytes. About 37-50% of the male birds in the different Fz-fed groups had testicular degeneration varying from mild to cystic enlargement. The degenerated testes had dilatation of seminiferous tubules; in cystic testes the seminiferous tubules were extremely dilated and had flattened epithelium. The interstitial tissue between the dilated tubules was compressed and atrophic.

Administration, Oral↗
PubMed1995

Co-localization of c-fos protein and protein kinase C gamma in the rat brain following anodal polarization.

The expression of protein kinase c gamma (PKC gamma) and c-fos protein was examined by means of double labeling in the rat brain in relation to the molecular mechanism of central plastic changes associated with anodal polarization. Under normal, non-polarized condition, approximately 75% of all fos positive neurons in the neocortex were immunopositive for PKC gamma. Conversely, nearly all PKC gamma positive neurons were fos immunopositive. Although both pyramidal and non-pyramidal neurons express both types of protein, the pyramidal cell type represents the vast majority. An anodal direct current of 3.0 microA for 30 min to the surface of the left sensorimotor cortex resulted in a pronounced increase in the intensity of immunoreactivity for both PKC gamma and c-fos protein ipsilateral to the polarization. Approximately, 91% of fos positive neurons in the polarized neocortex was also intensely immunoreactive for PKY gamma. The high degree of codistribution of both transduction proteins in specific neurons following anodal polarization suggests the functional connection between PKY gamma activation and c-fos expression in polarization phenomenon.

Animals↗
PubMed1995

Thrombosis and inflammation as multicellular processes: significance of cell-cell interactions.

Platelet activation as a result of vascular injury provokes endothelial cells to respond in a manner which limits or reverses the occlusive consequences of platelet accumulation. If the agonistic forces are strong, platelet accumulation is irreversible. In vitro data from our laboratory have repeatedly demonstrated that platelets become unresponsive to all agonists when in proximity to endothelial cells. This unresponsiveness is due to at least three separate endothelial "thromboregulatory" systems: eicosanoids, endothelium-derived relaxing factor (EDRF/NO), and most importantly an endothelial cell ecto-nucleotidase which metabolizes released platelet adenosine diphosphate (ADP) with consequent restoration of platelets to the resting state. This nucleotidase is operative in the complete absence of EDRF/NO and eicosanoids, indicating that the latter two are dispensable thromboregulators. We have solubilized the human endothelial cell ectoADPase, as well as that from placental tissue. Candidate proteins from a purified ADPase fraction are now being studied in further detail. An understanding of the molecular biology of the ADPase gene may lead to development of therapeutic agents such as soluble forms of the enzyme as well as approaches toward up-regulation of ectoADPase activity. This could result in "early thromboregulation", i.e. prevention and/or reversal of platelet accumulation at sites of vascular damage via immediate metabolic removal of the prime platelet agonist-ADP.

Adenosine Diphosphate↗
PubMed1994

Anodal polarization induces protein kinase C gamma (PKC gamma)-like immunoreactivity in the rat cerebral cortex.

Protein kinase C gamma (PKC gamma)-like immunoreactivity was examined in the rat brain, employing the monoclonal antibody 36G9 raised against purified PKC gamma, after an application of weak anodal direct current to the surface of the sensorimotor cortex. Anodal polarization with 3.0 microA for 30 min resulted in a pronounced increase in the number of PKC gamma-like-positive neurons in accordance with the intensity of PKC gamma-like immunostaining in the neocortex, cingulate cortex and piriform cortex ipsilateral to the polarization. The number of PKC gamma-like-positive neurons began to increase at 1 h after polarization, peaked at 3 h, and thereafter decreased to the control levels by 72 h. The increase in expression of PKC gamma-like immunoreactivity in specific areas of the cerebral cortex is suggested to serve as a basis for the long-lasting hyperexcitability in situ following anodal polarization.

Animals↗
PubMed1994

An analysis of Xenopus tyrosine kinase genes and their expression in early development.

Xenopus laevis and X. borealis were screened for tyrosine kinase genes using the polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR and 34 X. laevis and 23 X. borealis tyrosine genes were identified. Eighteen of the genes represented novel tyrosine kinase family members. The rest could be classified into known tyrosine kinase subfamilies, of which however only three have been previously identified in Xenopus. Eight clones, including bFGFR (xFGFR1) and potential Trk, Ins R., Fak, Fyn, and Abl homologs, were used to probe temporal and spatial gene expression in early development. Quantitative RT-PCR and whole-mount and in situ hybridization showed that most of these mRNAs were present throughout development and were broadly distributed, mainly in ectodermal and mesodermal derived tissues. At the blastula stage, bFGFR mRNA was detected within the ectoderm and a gradient of expression was noted within the invaginating mesoderm. The unexpected promiscuous expression of many tyrosine kinase genes in early development is discussed.

Amino Acid Sequence↗
PubMed1994

Repeated application of anodal direct current produces regional dominance in histamine-elicited cyclic AMP accumulation in rabbit cerebral cortex.

A unilateral 30-min application of anodal direct current to the promotor cortex of rabbits was repeated 10 times, and cyclic AMP accumulation in response to histamine was investigated in slices of different cortical areas. Polarization with 1.0 microA decreased the cyclic AMP accumulation in the cortical area contralateral to the polarization, by which regional dominance in cyclic AMP accumulation was produced in the polarized cortex. In contrast, the regional difference in cyclic AMP accumulation was reversed when 10.0 or 30.0 microA was applied. The histamine-elicited accumulation of cyclic AMP was almost completely inhibited by the selective H2-receptor antagonist cimetidine. These results suggest that repeated anodal polarization regionally alters H2-receptor-mediated cyclic AMP generation in the cortex depending on the intensity of the polarizing currents and this pattern of cyclic AMP accumulation is responsible for the characteristic motor behavior induced by anodal polarization.

Animals↗