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M Anwar

Publications and source records attributed to M Anwar.

At least 19 recordsLinked to original sources
PubMed1997

Induction of c-fos gene expression by spinal cord transection in the rat.

Sympathetic nerve activity is maintained after high spinal injury through circuits that remain in question. We evaluated patterns of c-fos gene induction as a monitor of spinal neurons responding to high spinal cord transection in the rat. Rats were anesthetized with isofluorane. Lower cervical or upper thoracic spinal segments were exposed, immersed in warm mineral oil and transected. Spinal cords were exposed but not transected in anesthetized controls. After 2.5 h, spinalized and control rats were perfused for immunocytochemistry. Cervical and thoracolumbar spinal segments and dorsal root ganglia were sectioned coronally. Tissues were incubated in primary, polyclonal antisera raised in rabbit or sheep against a peptide sequence unique to the N-terminal domain of Fos, and processed immunocytochemically. Neurons were induced to express Fos-like immunoreactivity (FLI), bilaterally, in the spinal gray, but not in primary sensory ganglia. Spinal cord transection induced neurons to express FLI in thoracic laminae I, IIo (outer substantia gelatinosa), Vre (lateral reticulated division), VII (lamina intermedia) and X, and the intermediolateral cell column. Lamina VIII was also labeled in spinal-injured but not in control animals. Immunolabeled nuclei were prominent in lumbar segments and were concentrated in the medial third of laminae I and IIo, and in laminae VII and X. Few cells were labeled in upper cervical or sacral segments. FLI was sparse in the spinal gray of controls and expressed mainly within the dorsal root entry zone of upper thoracic segments. Patterns of c-fos gene expression were site-specific and correlated with laminae that respond predominantly to noxious stimulation and that contain sympathetic interneurons. Laminae that are responsive to non-noxious stimuli and activated by walking, IIi, nucleus proprius, medial V and layer VI were not induced to express FLI. We conclude that neurons in specific spinal laminae that process high threshold afferents and that harbor neurons with sympathetic nerve-related activity are activated selectively by spinal cord transections. We hypothesize that peripheral afferents processed by spinal-sympathetic circuit neurons may regulate sympathetic discharge in the absence of supraspinal drive.

Animals↗
PubMed1997

The pedunculopontine tegmental nucleus issues collaterals to the fastigial nucleus and rostral ventrolateral reticular nucleus in the rat.

The pedunculopontine-laterodorsal tegmental nuclear complex was identified as a major source of brainstem afferents terminating in the fastigial cerebellar nucleus and/or ventrolateral reticular nucleus (n.Rvl). Collaterals from the pedunculopontine nucleus (Ch5 area) to rostral [vasopressor] regions of the fastigial nucleus and ventral reticular formation were revealed with a combined retrograde tracing technique. The data implicate acetylcholine as a transmitter and raise the hypothesis that the identified afferents may contribute to the autonomic and behavioral responses to midline cerebellar stimulation.

Afferent Pathways↗
PubMed1997

Induction of c-fos gene expression by spinal cord transection in Sus scrofa.

Functional responses of primary sensory afferents and spinal cord were monitored in swine subjected to a high cervical (C1) spinal transection. Two and a half hours after transection, dorsal root ganglia and cervical and thoracolumbar spinal segments were processed immunocytochemically for the c-fos gene product, Fos and related antigens. In spinal-transected animals, Fos-like immunoreactivity (FLI) was induced in spinal laminae I, V, VII and X and the intermediolateral cell column but not in sensory ganglia as compared to controls: spinal-intact age-matched littermates. Spinal laminae expressing FLI harbor sympathetic and somatic interneurons and may aid in maintaining sympathetic outflow.

Animals↗
PubMed1997

Effects of hyperosmolar mannitol on regional oxygen supply and consumption in the newborn pig.

Previous work indicated that opening the blood-brain barrier with hyperosmotic mannitol decreased local venous O2 saturation and increased cerebral O2 consumption. This study was performed to assess the vascular effect of hypertonic mannitol on oxygen supply/consumption balance in the newborn pig and to determine the role of nitric oxide in mediating the effects of mannitol. Animals were anesthetized with alpha-chloralose and mechanically ventilated to maintain their blood gases within normal range. Retrograde catheterization of the right carotid artery was performed to inject 12 ml to 25% mannitol over a 30 sec interval. In one group of animals (n = 5), the blood-brain barrier transfer coefficient (Ki) to 14C-alpha aminoisobutyric acid or 14C-urea (n = 4) was measured 12 min after mannitol. In another group of animals (n = 9), regional cerebral blood flow and small vein O2 saturation was measured using 14C-iodoantripyrine and microspectrophotometry. Similar measurements were made in other groups of animals (n = 9) after pretreatment with 10 mg kg-1 i.v. of N-omega-nitro-L-arginine methyl ester (L-NAME), 20 min before mannitol injection. The mannitol injection did not increase Ki or local cerebral O2 consumption. It resulted in a decreased small vein O2 saturation in the ipsilateral cortex (46 +/- 3%) in comparison to the contralateral cortex (55 +/- 2%). The O2 supply/consumption ratio decreased in the ipsilateral cortex in the mannitol injected animals (2.14 +/- 0.23) in comparison to the contralateral cortex (2.76 +/- 0.28). Pretreatment with L-NAME abolished this effect of mannitol (small vein O2 saturation 59 +/- 2% in ipsilateral cortex and 58 +/- 2% in the contralateral cortex; O2 supply/consumption 2.68 +/- 0.17 in the ipsilateral cortex and 2.65 +/- 0.16 in the contralateral cortex). We conclude that hypertonic mannitol adversely affects O2 supply/consumption balance, without increasing blood-brain barrier transport, and this effect is blocked by L-NAME, a nitric oxide synthase antagonist.

Aminoisobutyric Acids↗
PubMed1997

Management of acute respiratory infections by mothers in the community.

Home treatments are important in the management of acute respiratory infection (ARI). In order to examine how urban mothers in Lahore, managed ARI, a study was carried out within 1-km radius of a teaching hospital. A total of 50 mothers who had at least one child aged 2 months-5 years with an ARI from each of three settings-a lower class locality, a middle class locality and the outpatient department of the hospital were interviewed during the winters of 1992-93. A substantial proportion of mothers, particularly those from the lower class locality (44%), did not use home treatment for acute respiratory infection. The majority of mothers indicated that they would not use home treatment if their child had an ARI in the future. The importance of home treatment has to be introduced into the community probably by programmes conducted by health professionals.

Acute Disease↗
PubMed1997

Bone marrow involvement in Hodgkin's disease: the significance of non-infiltrative changes.

We have tried to elucidate the significance of so called non-infiltrative changes in order to find their place in the staging procedure particularly in countries where facilities for elaborate clinical staging are not available. Seventy nine out of 88 patients were classified into 3 groups depending upon the histological findings in their bone marrow trephine biopsies. Bone marrow in Group-I (n = 20) patients was essentially normal. The established criteria of bone marrow involvement were fulfilled in Group III patients (n = 25); while bone marrow in Group-II patients (n = 34) showed non-infiltrative changes. The clinical presentation, peripheral blood parameters and LDH levels of the 3 groups of patients were compared. There was progressive anaemia, neutrophilic leucocytosis and increase in ESR from Group I to III. The change was statistically significant when Group I was compared with Group II or Group III but non-significant when Group II was compared with Group III. It is, therefore, postulated that both Groups II and III reflect the bone marrow involvement although the changes observed in Group II do not satisfy the previously established criteria for this purpose.

Adolescent↗
PubMed1996

Vestibular afferents to the dorsal vagal complex: substrate for vestibular-autonomic interactions in the rat.

Vestibular afferents to the nucleus tractus solitarii (NTS) were identified for the first time in the male Sprague-Dawley rat. Cells of vestibular origin were labeled by deposits of cholera toxin B (CT-B) centered on the general viscerosensory division of NTS and dorsal motor nucleus (DMX). Vestibular-visceral afferents derive from neurons concentrated at caudal levels of medial and inferior vestibular nuclei as observed in other species. Vestibular afferent processes were labeled in the NTS and DMX by anterograde transport of the tracer, biotinylated dextran-amine from injection deposits confined to the inferior and/or medial vestibular nuclei. Vestibular axons terminate in the NTS, predominantly at intermediate levels of the dorsal vagal complex. Projections overlapped sites in NTS that receive terminal input from first-order alimentary and cardiorespiratory afferents. The somato-visceral reflex circuit corroborates recent evidence in the rat of increases in functional activity in the vestibular nuclear complex and NTS in response to changes in gravito-inertial force [Kaufman, G.D., Anderson, J.H. and Beitz, A.J., J. Neurosci., 12 (1992) 4489-4500]. Vestibular input to the NTS and DMX may assist in compensating for the effects imposed by movements and gravity on breathing, alimentary reflex function and the systemic circulation.

Afferent Pathways↗
PubMed1996

Hypotension-induced expression of the c-fos gene in the medulla oblongata of piglets.

Neural networks that mediate the reflex response to baroreceptor withdrawal were explored in Sus scrofa. Induction of c-fos was used as a monitor of synaptic activity in response to hypotension sustained by systemic administration of a peripheral vasodilator, sodium nitroprusside. Patterns of c-fos gene expression were compared between Saffan-anesthetized experimental animals and age-matched normotensive controls administered vehicle. Effects of other variables were controlled including 1 h preoperative accommodation to the novel environment, anesthesia, blood gases and pH. Identical post-stimulus survival periods were allowed for accumulation of transcript. The c-fos protein, Fos, was identified immunocytochemically with two rabbit antisera raised against amino acids 1-131 of Fos or residues 4-17 of synthetic human transcript. Fos was identified in catecholaminergic neurons labeled with an antiserum to tyrosine hydroxylase (TH). Fos was induced in the nucleus tractus solitarii (NTS) of hypotensive piglets. Neurons encoding Fos matched projection patterns of first order visceral afferents. Induction was prominent in the dorsolateral nucleus coinciding with the baroreceptor field. Indices of increased neuronal activity were evident in other baroreceptor terminal sites, e.g., medial subnucleus, the medial commissural field, the intermediate subnucleus and a ventral A2 noradrenergic area. In reticular formation c-fos protein was induced in circumscribed columns in the lateral tegmental field (LTF) extending from facial nucleus to calamus scriptorius. Catecholaminergic (TH-positive) neurons expressed Fos in the porcine C1 and A1 areas of ventrolateral medulla. Fos was also induced in a dorsal intermediate reticular zone of LTF. Minor or inconsistent differences between experimental and control were observed in nucleus raphe pallidus, rostral paramedian reticular formation, upper thoracic intermediolateral cell column, and stellate ganglia. In conclusion, baroreceptor withdrawal in young animals induced patterns of neuronal response along established cardiovascular reflex pathways.

Animals↗
PubMed1996

Central and primary visceral afferents to nucleus tractus solitarii may generate nitric oxide as a membrane-permeant neuronal messenger.

An anatomical basis was sought for the postulated roles of nitric oxide (NO) as a labile transcellular messenger in the dorsal vagal complex (NTS-X). The diaphorase activity of NO synthase was used as a marker of neurons in NTS-X that are presumed to convert L-arginine to L-citrulline and NO. Nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) staining patterns in the nucleus tractus solitarii (NTS) were spatially related to terminal sites of primary visceral afferents from 1) orosensory receptors (e.g., rostral-central nucleus); 2) soft palate, pharynx, larynx, and tracheobronchial tree (e.g., dorsal, intermediate, and interstitial nuclei); 3) esophagus (nucleus centralis); 4) stomach (nucleus gelatinosus); 5) hepatic and coeliac nerves (nucleus subpostrema); and 6) carotid body and baroreceptors (medial commissural and dorsal-lateral nuclei). Primary visceral afferents were identified as sources of NADPHd-stained fiber plexuses in the NTS-X based on three findings: 1) the presence of NADPHd in nodose ganglion cells with morphological features of first-order sensory relay neurons; 2) retrograde transport of Fluoro-Gold (FG) or cholera toxin B (CT-B) from NTS-X to NADPHd-positive nodose ganglion neurons; and 3) striking reductions of NADPHd-stained processes within primary vagal projection fields ipsilateral to unilateral nodose ganglionectomy. A central origin of NADPHd-stained processes in NTS-X was identified in the medial parvicellular subdivision of the paraventricular hypothalamic nucleus. We conclude that NO of peripheral and central origin may modulate viscerosensory signal processing in the NTS-X and autonomic reflex function.

Afferent Pathways↗
PubMed1996

Blood pressure ranges in premature infants: II. The first week of life.

OBJECTIVE: To examine the arterial blood pressure in the first week of life in a healthy premature population. DESIGN: Population-based cohort study. SETTING: Three intensive care nurseries in central New Jersey. PATIENTS: Premature infants with birth weights less than 2000 g. MAIN OUTCOME MEASURES: We documented daily maximum and minimum systolic and maximum and minimun diastolic blood pressures during the first 7 days of life. To examine the effects on the ranges of blood pressure, we identified four groups of infants: (1) healthy infants without any of the major risk factors (n = 193); (2) infants who were mechanically ventilated but free of any of the other conditions (n = 225); (3) infants with histories of maternal hypertension or preeclampsia (n = 38) and (4) infants with low Apgar scores (less than 3 at 1 minute and less than 6 at 5 minutes) regardless of the presence of other conditions (n = 86). RESULTS: Blood pressure increased steadily in the first week of life in all four groups. There was no relationship between any of the four blood pressure variables, or trends in blood pressure over time, with birth weight, gender, or race. Regression equations (based on all infants with available data) for blood pressure ranges by day of life revealed that the maximum systolic blood pressure increased by 2.6 mm Hg/d, the minimum systolic blood pressure increased by 1.8 mm Hg/d,the maximum diastolic blood pressure increased by 2.0 mm HHg/d, and the minimum diastolic blood pressure increased by 1.3 Hg/d. CONCLUSIONS: Infants with birth asphyxia and ventilated infants had significantly lower systolic and diastolic blood pressures than healthy infants.

Age Factors↗
PubMed1996

Effects of hemorrhagic hypotension on cerebral blood flow and perfused capillaries in newborn pigs.

We examined the effect of hemorrhagic hypotension on cerebral blood flow and perfused capillaries in newborn pigs, 2-10 days old. Cerebral blood flow was measured by using radioactive microspheres, perfused capillaries were determined by infusing a plasma marker, fluorescein isothiocyanate (FITC) - dextran (molecular mass 147,000 Da), and total capillaries were determined by staining with alkaline phosphatase. Rapid removal of 66 +/- 16 mL of blood resulted in a fall in mean blood pressure from 68 +/- 6 to 31 +/- 4 mmHg (1 mmHg = 133.3 Pa), an increase in heart rate from 137 +/- 18 to 240 +/- 34 beats/min, and a drop in arterial pH from 7.33 +/- 0.05 to 7.23 +/- 0.07. PCO2 was controlled by mechanical ventilation (36 +/- 4 mmHg before hemorrhage and 35 +/- 5 mmHg after hemorrhage) and PO2 remained stable (89 +/- 11 mmHg before hemorrhage and 94 +/- 10 mmHg after hemorrhage). Blood flow (n = 9) did not fall significantly in any brain region after hemorrhage. The percentage of perfused capillaries/mm2 (control, n = 7, hemorrhage, n = 6) was reduced in all brain regions during hypotension (cortex from 72 +/- 8 to 57 +/- 8%, cerebellum from 75 +/- 10 to 52 +/- 10%, and medulla from 76 +/- 8 to 51 +/- 9%). Similar results were seen for perfused capillary surface area We conclude that hemorrhagic hypotension resulted in a variable blood flow response with no significant reduction in cerebral blood flow but a reduction in perfused capillary number and surface area in all brain regions studied. We speculate that decreased capillary perfusion may be a contributing factor in diffuse neuronal injury after severe hemorrhagic hypotension.

Animals↗
PubMed1995

Sex allocation and population structure in malaria and related parasitic protozoa.

Here we demonstrate how sex allocation theory, one of the best verified areas of metazoan evolutionary biology, can be successfully applied to microparasitic organisms, by relating parasite prevalence and sex ratio in the Haemosporina. Members of this taxon, which includes Plasmodium, are parasitic protozoa with obligate sexual cycles in which dioecious haploid gametes drawn from the peripheral blood of a vertebrate host fuse within a dipteran vector. Consequently mating takes place within a highly subdivided population, a condition known to promote local mate competition and inbreeding and hence the evolution of female-biased sex ratios. We used an epidemiological framework to investigate mating patterns and sex ratio evolution within natural populations of these parasites. This phenotypic approach compliments more conventional biochemical approaches to the population genetics of parasitic protozoa. Data are presented which support a theoretical relation between transmission-stage sex ratio and prevalence across parasite populations. These results are consistent with a large inter-population variation in genetic structure and argue against sweeping generalizations about the clonality or otherwise of populations of these parasitic protozoa.

Animals↗
PubMed1995

Medullary visceral reflex circuits: local afferents to nucleus tractus solitarii synthesize catecholamines and project to thoracic spinal cord.

Visceral feedback circuits in lower brainstem were elucidated with retrograde tracers by mapping neurons that issue local projections to the general visceral afferent division of the nucleus tractus solitarii (NTS) and dorsomotor vagal nucleus (DMX) in adult male rats. In study 1, spinal and intramedullary afferents to the visceral-sensorimotor complex (NTS-X) were traced to contiguous populations of cell bodies arranged in cylindrical segmental organization. NTS-X afferents derive from curvilinear arrays of neurons that parallel the efferent radiations of the solitariotegmental tract. Newly discovered afferents arise from circumscribed cell groups in the dorsal reticular formation and periventricular zone. Another source was traced to a paraambigual cell column in the apex of the rostral ventrolateral reticular nucleus (n.RVL). In study 2, catecholaminergic afferents were initially defined with combined retrograde transport-immunocytochemical methods. Deposits of retrograde tracers into NTS-X transported to neurons containing tyrosine hydroxylase (TH) in the A1, C1, and C3 areas or phenylethanolamine N-methyltransferase (PNMT) in the C1 area of the n.RVL and C3 area. In study 3, it was revealed that NTS-X afferents arise, in part, as collaterals of thoracic reticulospinal neurons. Deposits of the retrograde fluorescent tracer Fluorogold into the upper thoracic cord and rhodamine-labeled microbeads into NTS-X transported to the same neurons within a subambigual locus in n.RVL and parts of nucleus raphe magnus. In study 4, dual retrograde tracer-immunocytochemical analysis demonstrated that catecholamines are synthesized by a subset of neurons in the n.RVL that issue collaterals to the NTS-X and thoracic cord. Double retrogradely labeled TH- or PNMT-immunoreactive cell bodies were restricted to the C1 area within a 450-microns column bordered rostrally by the facial nucleus and ventrally by the medullary subpial surface. We conclude that visceral reflex arcs are reciprocally organized. Targets of NTS projection are also sources of local NTS-X afferent innervation. Catecholaminergic and other local afferents from reticular formation, periventricular, and spinal gray may, via collaterals, simultaneously modulate visceral reflex excitability at the level of NTS and the outflow of autonomic and respiratory motoneurons.

Animals↗
PubMed1995

Disseminated intravascular coagulation in acute leukaemias at first diagnosis.

Haemorrhagic diathesis is the commonest cause of morbidity and mortality in acute leukaemias (AL). It is most commonly due to thrombocytopenia resulting from bone marrow failure. However, in a significant number of cases, disseminated intravascular coagulation (DIC) plays an important part. Previously it was thought that this mechanism was mainly confined to acute promyelocytic leukaemia (APL), but recently it has also been reported to occur in other subtypes of acute leukaemia. We report the results of a study carried out to find the incidence of DIC in various types of AL at the time of first diagnosis and in the absence of other recognisable causes. DIC was observed in 14(13.4%) cases out of 104 cases of AL studied. Nine out of 49(18.4%) cases of AML and 5 out of 55(9.1%) cases of acute lymphoblastic leukaemia (ALL) showed coagulation abnormalities consistent with DIC. Out of the 9 cases of AML showing DIC, 63 (66.67%) belonged to APL (FAB ME) subtype. Three (60%) out of 5 cases of ALL with DIC had T-cell immunophenotype. The results indicate that DIC may also occur in types of AL other than APL, particularly in T-ALL, and should be looked for.

Adolescent↗
PubMed1995

Serum ferritin levels in carriers of beta-thalassaemia trait.

Hypochromic and microcytic red cell morphology is the most commonly encountered abnormality in a clinical laboratory. Most of such cases have iron deficiency anaemia. However, in Pakistan about 5% of the individuals with a hypochromic and microcytic blood picture have the beta-thalassaemia trait. These individuals are more than often in a positive iron balance. However iron deficiency (being common) may be associated with the beta-thalassaemia trait. This study of serum ferritin levels was carried out on 135 confirmed cases of the beta-thalassaemia trait. A ferritin assay was done by a radioimmunoassay technique. The results show that the level of serum ferritin in 100 (74%) cases was within normal limits, in 17 (12.6%) cases it was above the normal range, whereas in 18 (13.4%) cases the level was lower than normal. The importance of serum ferritin estimation in carriers of the beta-thalassaemia trait is highlighted.

Adolescent↗
PubMed1995

Evaluation of M/H ratio for screening of beta thalassaemia trait.

This study was done to evaluate the efficiency of M/H ratio between the percentages of microcytic and hypochromic cells as a screening procedure for thalassaemia trait in Pakistani population. A total of 150 subjects, were included in this study. The analysis of results revealed that M/H ratio is a very sensitive index for beta thalassaemia trait. The sensitivity, predictive value and diagnostic accuracy of the M/H ratio for beta thalassaemia trait was 100%, 90.4% and 90.4% respectively. It also picked up all cases of beta thalassaemia trait with co-existent iron deficiency. It is therefore concluded that M/H ratio is an easy, reliable and sensitive index which can be used for mass screening of beta thalassaemia trait, particularly in a population where iron deficiency is also prevalent.

Adolescent↗
PubMed1995

Granulocytic sarcoma in patients with chronic myeloid leukaemia.

Granulocytic sarcoma is an unusual variant of myeloid malignancy most commonly encountered in the course of chronic or acute myeloid leukaemia. Of 60 patients of chronic myeloid leukaemia studied over 21 months, we encountered 6 (10%) cases of granulocytic sarcoma. Four of these had granulocytic sarcoma on their first presentation. All those who were receiving hydroxyurea did not fare well but one who was put on DAT (daunorubicin, cyftosine arabinocide, 6 thioguanine)regimen went into remission with complete disappearance of lesions.

Adolescent↗