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Biomedical subjects

M Y Hasan

Publications and source records attributed to M Y Hasan.

At least 19 recordsLinked to original sources
PubMed2004

Trace metal profiles in hair samples from children in urban and rural regions of the United Arab Emirates.

Pollution has increased with industrialization and humans are subjected to exposure to heavy metals from different environmental sources. In oil-producing countries heavy metals are considered a major threat to the population. Metals such as lead, aluminum, manganese, nickel and cadmium may impact various organs of the body, and controlling their toxicity is crucial for individuals at risk. Previous studies utilized blood levels for monitoring metal toxicity. The current study was designed to investigate exposure to lead, aluminum, manganese, nickel and cadmium using scalp hair. Hair samples were randomly collected from 42 children (aged 6-18 y) representing rural and urban areas of the United Arab Emirates. The rural regions were defined as at least 50 km away from factories or traffic sites. Immediately after cutting, hairs were stored in plastic bags and attached to a questionnaire with the relevant background information. Samples were dried, weighed and sealed with polyethylene envelopes. Following extraction procedures with nitric acid, ICP-MS was utilized for metals determination. The analytical instrument showed a high degree of sensitivity and revealed significant differences between levels of some metals in hairs from rural and urban areas. Children from rural areas had mean hair lead levels (microg/g) of 0.79 + 0.10 whereas children from urban area had higher hair lead levels (3.47 + 0.47). Measuring metals concentration in scalp hair could be a useful method for studying exposure and assessing environmental pollution. Although the technique has the potential of being an effective tool for evaluating extent of pollution and identifying potentially toxic elements, it cannot yet replace the standard procedures of measuring air, water and soil metal content.

Adolescent↗
PubMed2003

Effects of ascorbic acid on lead induced alterations of synaptic transmission and contractile features in murine dorsiflexor muscle.

Lead is a common environmental toxin that affects neuromuscular junction and potentially might cause muscle weakness. Antioxidants like ascorbic acid may protect against lead induced myopathy. The present study measured isometric twitch tensions (evoked either directly by muscle stimulation or indirectly by nerve stimulation) to study effects of ascorbic acid on lead induced alterations at murine dorsiflexor skeletal muscle. Resting membrane potentials (RMPs), endplate potentials (EPPs) and miniature endplate potentials (MEPPs) were also recorded. Forty animals were divided into four groups of n = 10 each. (10 control, 10 lead alone, 10 ascorbic acid alone, 10 lead treated plus ascorbic acid). Lead (1 mg/kg) i.p, was administered daily for 2 weeks before the recording day and ascorbic acid (200 mg/kg, i.p) was given daily for 3 weeks prior to the experiment day. Lead treatment reduced twitch tension significantly (from 4.3 +/- 0.5 g to 2.7 +/- 0.2 g) and delayed half time of decay compared to the control. Similarly MEPPs frequencies were reduced following lead treatment. Application of ascorbic acid prevented twitch tension reduction in lead treated mice (3.3 +/- 0.3 g) and reversed lead induced delay in half time of decay. The negative actions of lead treatment on MEPPs frequencies were also modified with ascorbic acid. It appears that ascorbic acid exerts a protective role against lead induced peripheral nerve and muscle dysfunction. This effect of ascorbic acid on lead induced neuromyopathy is probably mediated via a free radical scavenging mechanism or modification of Ca(2+) homeostasis.

Animals↗
PubMed2003

Factors influencing the quality of life of infertile women in United Arab Emirates.

OBJECTIVES: To measure the quality of life in a representative sample of infertile women and evaluate their sociocultural attitude to this condition. METHODS: Two hundred sixty-nine infertile women attending the Assisted Reproduction clinic, Tawam Hospital were consecutively selected. They were interviewed about the effect of infertility on their quality of life using a structured, measurement-specific and pre-tested questionnaire. RESULTS: Parameters mostly affected were mood-related mainly in women above 30 years, with primary and female factor infertility and those in polygamous marriages. Quality of life did not affect sexual performance and was not affected by duration of infertility or cost of treatment. CONCLUSION: The results highlight the importance of bearing children and the stresses exerted on infertile women in Eastern societies. Thorough counseling and continuing support of infertile women is therefore indicated to improve their quality of life.

Adolescent↗
PubMed2003

PD-136,450: a CCK2 (gastrin) receptor antagonist with antisecretory, anxiolytic and antiulcer activity.

This study investigated the effects of PD-136,450 (PD), a highly selective ligand for the CCK2 receptor, on gastric acid and pancreatic secretions, gastric cytoprotection and anxious behaviour in the rat and rabbit. PD inhibited gastrin (but not dimaprit) stimulated acid secretion in anaesthetized and conscious rats (IC50 of 1 mg kg(-1) sc) and inhibited 14C-aminopyrine uptake in isolated gastric glands from rabbits. In addition, PD decreased dose-dependently gastric haemorrhagic lesions in rats treated orally with acidified ethanol. Both, the antisecretory effects on gastric acid secretion and the gastric cytoprotective effects were less potent compared with the proton pump inhibitor omeprazole. PD strongly increased pancreatic secretion, which was substantially inhibited by the CCK1 antagonist L-364,718 (but not by the CCK2 antagonist L-365,260). PD also showed significant anxiolytic activity as assessed by a black and white box two-compartment activity assay. Both, time spent in the dark compartment and latency for movement from the light to the dark compartment was increased by PD (similarly with 5 mg kg(-1) diazepam). In conclusion, PD inhibited gastrin-stimulated gastric acid secretion, decreased ethanol-induced damage to the gastric mucosa, stimulated pancreatic secretion (via CCK1 receptors) and displayed anxiolytic activity. Thus, PD may have utility as an adjunct therapy in peptic ulcer disease by countering the actions of gastrin and increasing acid neutralization and mucosal protection.

Animals↗
PubMed2003

Effects of alpha-tocopherol on diabetes-induced alterations of synaptic transmission and contractile features in murine dorsiflexor muscle.

Diabetes mellitus affects skeletal muscle and free radicals may be implicated in the manifestation of diabetes complications. The present study investigated effects of alpha-tocopherol on diabetic dorsiflexor muscle via recording resting membrane potentials (RMPs), endplate potentials (EPPs), miniature endplate potentials (MEPPs) and isometric twitch tensions. Forty mice were divided randomly into two groups (n = 20). One group served as control and the other was injected once with streptozotocin (STZ) solution (60 mg/kg, i.p) to induce diabetes. The animals were then divided further into two subgroups (n = 10). Alpha-tocopherol (100 mg/kg, i.p) was administered daily to one control and one diabetic group for 3 weeks prior to recording day. Experiments were conducted 4 weeks following diabetes induction. Isometric twitch tension was measured in anaesthetized mice (2 mg/g urethane, i.p) via a transducer connected to a computer system. Resting membrane potentials and MEPPs were measured by utilizing the intracellular recording method. Compared to control, diabetic mice showed reduced twitch tension (4.4 +/- 0.4 g control vs. 2.5 +/- 0.3 g diabetic) and demonstrated delayed half time of decay. Diabetic flexor muscle also displayed significant reduction in MEPPs frequencies with no changes in RMPs. Alpha-tocopherol reversed tension reduction in diabetic mice (from 2.5 +/- 0.3 to 3.8 +/- 0.4 g), impacted delayed half time of decay and reversed reduction in MEPPs frequencies. Alpha-tocopherol exerts a protective role against diabetes-induced peripheral muscle dysfunction. This effect is probably mediated via a free radical scavenging mechanism or modification of Ca2+ homeostasis.

Animals↗
PubMed2002

Student perceptions of tutor skills in problem-based learning tutorials.

OBJECTIVE: The problem-based learning (PBL) tutor plays a role that is different from the role of a teacher in a conventional teaching format. In the Faculty of Medicine and Health Sciences, United Arab Emirates, all students are Arab nationals and tutors are expatriates with different sociocultural backgrounds from the students. This study was designed to investigate how students evaluate tutors in PBL tutorials and whether student evaluations of tutors change with the progress of students in PBL tutorials. METHODS: Differences in tutor performance evaluation by male and female students were also analysed. The students evaluated 12 tutor skills in a scale of 1-3, 1 being 'below average' and 3, 'outstanding'. Student responses from a total of 314 (98.1%) completed forms collected over 2 academic years were analysed statistically. A total of 14 tutors participated in the PBL programme. RESULTS: The analysis revealed that tutors as a group were rated as having average to outstanding tutor skills in 10 items of the evaluation form. Students and faculty perceptions were different for the tutor skills of guiding students for information management. The students expected more support from tutors, whereas the tutors tried to emphasize self-learning in the PBL curriculum. Lower scores to the tutors in the 'problem' bringing sociocultural and religious issues for discussion showed that a gap in sociocultural/religious understanding between students and tutors might influence tutor skills. CONCLUSIONS: Differences in tutor evaluation by male and female students indicate necessity of adopting different strategies by tutors in a different sociocultural background. The results of the study have direct implications for faculty development.

Attitude↗
PubMed2001

Reduced potassium currents in old rat CA1 hippocampal neurons.

Potassium currents are an important factor in repolarizing the membrane potential and determining the level of neuronal excitability. We compared potassium currents in CA1 hippocampal neurons dissociated from young (2-3 months old) and old (26-30 months old) Sprague-Dawley rats. Whole-cell patch-clamp techniques were used to measure the delayed rectifier (sustained) and the A-type (transient) potassium currents. The delayed rectifier current was smaller in old (548 +/- 57 pA) than in young (1193 +/- 171 pA) neurons. In the absence of extracellular calcium, the delayed rectifier current was also smaller in old (427 +/- 41 pA) than in young (946 +/- 144 pA) neurons. The cell membrane capacitance was unchanged in old (13.3 +/- 1.2 pF) compared to young (13.6 +/- 1.2 pF). Therefore, the reduction in the delayed rectifier current was not due to a change in membrane surface area. Moreover, activation and inactivation of the delayed rectifier current were unchanged in old compared to young neurons. The slope of the current-voltage relation, however, was smaller in old (B = 5.03) than in young (B = 9.62) neurons. Similarly, the A-current was smaller in old (100 +/- 16 pA) than in young (210 +/- 44 pA) neurons in the presence of extracellular calcium. This reduction of potassium currents could account for the prolongation of action potentials reported previously for old rat CA1 hippocampal neurons. The age-related reduction in potassium current indicates plasticity in neuronal function that can impact communication in the hippocampal neural network during aging.

Aging↗
PubMed2000

Water deprivation reveals early neuromyopathy in diabetic mice.

The effects of water deprivation on peripheral nerve and muscle function were investigated in flexor digitorum superficialis muscle of control and diabetic mice. Twenty mice (30 g average body weight) were injected once with streptozotocin solution (200 mg/kg) to induce experimental diabetes and another 20 mice of similar body weight served as controls. Two weeks later, comparative analyses of in situ muscle isometric contractile characteristics were performed by direct muscle stimulation and indirect nerve stimulation (at 1, 5 and 30 Hz) in urethane-anesthetized (2 mg/g, i.p.) control and diabetic mice. One day prior to the experiments, 10 control and 10 diabetic mice were deprived of water. The study contained four groups: hydrated (H) control, dehydrated (DH) control, H diabetic and DH diabetic. There were no significant differences in synaptic delay or twitch tension between H control and DH control. Comparing H control and H diabetic groups, no differences were noticed in synaptic delay or twitch tension; except at 30 Hz where twitch tension was reduced in H diabetic mice. Significant differences were observed when comparing DH control and DH diabetic mice. DH diabetic showed a significant increase in synaptic delay (from 7.4 to 9.3 ms) and a significant decrease in twitch tension evoked either by indirect nerve or by direct muscle stimulation (from 4.4 g to 1.9 g and from 4.4 g to 2.3 g, respectively). These results revealed that water deprivation enhances diabetes effects at the neuromuscular junction and at the muscle leading to further complication of neuromyopathy.

Animals↗
PubMed2000

Early morphological remodeling of neuromuscular junction in a murine model of diabetes.

Although skeletal muscle weakness is documented in diabetes, the time course for its development is not established. The present study examined the dorsiflexor muscle from animals that had been diabetic for 2 wk. Adult male c57BL mice were injected once with streptozotocin (STZ) to induce diabetes (60 mg/kg ip). Two weeks later, resting membrane potential and miniature end-plate potentials were recorded, and electron microscopy was utilized for ultrastructural evaluations. After STZ-induced diabetes, both resting membrane potential and miniature end-plate potentials were reduced. Nerve terminals showed less synaptic vesicles and had degenerated mitochondria. Furthermore, in the intramuscular nerves, disorganization of microtubules and neurofilaments was evidenced. Myelin-like figures were present in intramuscular nerves, neuromuscular junctions, and muscle fibers. At the muscle level, mitochondria were swollen, with disorganization of their cristae, disruption of T tubules, and myofibers with more deposition of glycogen granules. The present results revealed early STZ-induced nerve and muscle alterations. Observed ultrastructural modifications resemble those of motoneuron disorders and aging processes. These changes are possibly related to alterations in Ca(2+) mobilization across muscle membrane. Other mechanisms such as free radical-mediated actions may also be implicated in STZ-induced effects on skeletal muscle.

Animals↗
PubMed2000

Cadmium modulates diabetes-induced alterations in murine neuromuscular junction.

Skeletal muscle function is compromised in diabetes mellitus and exposure to heavy metals may further complicate neuromuscular impairments. The present study investigated the effects of cadmium on diabetes induced dorsiflexor muscle dysfunction in C57 BL adult male mice. Forty mice were divided randomly into 2 groups (n=20 each). One group served as control and the other was injected once with i.p. streptozotocin (STZ) solution (60 mg/kg) to induce experimental diabetes. Each group was then divided into two sub-groups (n=10) of which one received 5 mM cadmium. Utilizing intracellular recording method, resting membrane potential (RMP) and miniature endplate potentials (MEPPs) were measured in dorsiflexor muscle obtained from urethane-anaesthetized (2 mg/g, i.p.) four weeks diabetic and matched control mice. Comparative analyses of isometric contractile characteristics of in situ dorsiflexor muscle were also conducted in both groups. In control mice, flexor muscle exposure to 5 mM cadmium for 10 min resulted in significant reduction in MEPPs frequencies and isometric twitch tensions without affecting RMP. In STZ-diabetic mice, the same exposure did not modify resting membrane potential and further decreased MEPPs frequencies and isometric twitch tensions. Current results indicated that cadmium probably via a Ca2+ antagonist and chelating activity at nerve terminals exacerbates diabetes complications.

Animals↗
PubMed2000

Alternative medicine and the medical profession: views of medical students and general practitioners.

A survey was undertaken to explore the attitudes and practices of general practitioners and medical students in the United Arab Emirates with regards to forms of therapy not generally accepted by conventional medicine, including herbal medicine, acupuncture, homeopathy, spiritual therapy and osteopathy/chiropractic. The study found that alternative medicine is in common use to complement conventional medicine by a section of educated people within the health care system. Our observations lead us to appreciate its role in community health care and indicate a need to design culturally appropriate medical curricula which incorporate information about alternative medicine.

Adult↗
PubMed1999

Management of neuroleptic malignant syndrome with anticholinergic medication.

Neuroleptic Malignant Syndrome (NMS) is a life-threatening adverse reaction arising from the use of neuroleptic medications. While dopaminergic agonists, dantrolrene and supportive care are traditionally utilized in the stabilization and management of NMS, anticholinergic medication may also prove effective therapy. Treatment with anticholinergic medication has been suggested in cases of NMS associated with mild hyperthermia. We describe a case of 17-y-old female, who was brought to the emergency department for a possible "acute dystonic reaction". The patient received 50 mg diphenhydramine i.v., which resulted in improvement in mental status. The patient was readmitted to the emergency department 1 d following discharge with symptoms similar, but now considering the diagnosis of NMS. Diphenhydramine 50 mg i.v. was again administered and resulted in significant improvement.

Adolescent↗
PubMed1998

The views of senior students and young doctors of their training in a skills laboratory.

The study was carried out in the Faculty of Medicine and Health Sciences (FMHS), United Arab Emirates (UAE) University, UAE, where a skills laboratory was set up in 1988 to train medical students in clinical skills before they use such skills on patients. The students learn clinical skills using simulated patients, models and mannequins. The training starts in the first year of the 6-year undergraduate curriculum and continues until the end of the fourth year, after which students rotate through the clinical specialties. This study sought to identify: (1) the views of senior clerks (sixth year) and interns (first postgraduate year) regarding the clinical skills training in the skills laboratory (SKL) during the early years of the medical curriculum; (2) the differences in views between senior clerks and interns; (3) the differences in views between women and men students. Students' views about communication, interviewing, physical examination, therapeutic, diagnostic and laboratory skills were investigated. The results indicated that prior training in clinical skills was helpful to the senior clerks and the interns. Statistically significant differences in opinion were noted between the senior clerks and the interns, the interns being more positive about the usefulness of the SKL training compared with learning clinical skills directly on patients. There was no difference between men and women students except that women students were not comfortable with allowing their peers to examine any part of their bodies. The findings of the study have direct implications for the SKL programme.

Clinical Clerkship↗
PubMed1994

Cholecystokinin type B receptor antagonist PD-136,450 is a partial secretory agonist in the stomach and a full agonist in the pancreas of the rat.

Gastrin (cholecystokinin type B (CCK-B)) receptor antagonists may help to elucidate the physiological role of gastrin, have therapeutic potential as acid antisecretory drugs, and may be of use as adjuvant therapy for gastrin sensitive tumours. In binding studies, the gastrin receptor antagonist PD-136,450 had at least 1000 fold greater affinity for gastrin (CCK-B) than CCK-A receptors. In this study the biological activity of PD-136,450 was evaluated in conscious and anaesthetised rats. PD-136,450 antagonised gastrin stimulated acid secretion after subcutaneous (IC50: 0.28 mumol/kg; conscious rats) and intravenous (IC50: 0.17 mumol/kg; anaesthetised rats) administration. In basal secreting fistula animals, the compound stimulated acid output to 30 (5)% of the maximal response to gastrin. Stimulant activity was not caused by gastrin release. As an agonist PD-136,450 was about 350 times less potent than gastrin-17 on a molar basis. In addition, PD-136,450 was a powerful agonist of pancreatic secretion in anaesthetised rats. The specific gastrin antagonist L-365,260 inhibited the (partial) agonist activity of PD-136,450 in the stomach and the specific CCK-A receptor antagonist L-364,718 inhibited the agonist activity of PD-136,450 in the pancreas. It is concluded that the agonist effect of PD-136,450 is mediated via interaction with the gastrin (CCK-B) receptor in the stomach and the CCK-A receptor in the pancreas.

Animals↗
PubMed1990

Comparison of the inhibitory action of aminobeclamide and beclamide on socially offensive behaviour.

The inhibitory effects of aminobeclamide (N-(p-aminobenzyl)-beta-chloropropionamide) on socially offensive behaviour has been studied and compared with those of the parent drug beclamide (N-benzyl-beta-chloropropionamide). Following oral administration in mice which had been individually housed for a 28 day period then paired with normal group-housed opponents, aminobeclamide and beclamide both produced significant and dose-related inhibition of socially offensive behaviour. Aminobeclamide (20-150 mg kg-1 p.o.) and beclamide (50-250 mg kg-1 p.o.) gave increased offense onset latency whilst at the same time they reduced the incidence of offense encounters/animal and decreased the group percentage of animals displaying offense behaviour. It is likely that both drugs have similar monoamine modifying effects though this animal study suggests that aminobeclamide is 1.5 to 2.7 times more potent than beclamide against socially offensive behaviour.

Animals↗
PubMedDate not supplied

In vivo metoclopramide protection of cholinesterase from paraoxon inhibition: direct comparison with pralidoxime in subchronic low-dose exposure.

The benzamide compound metoclopramide (MCP) protects against cholinesterase inhibition by paraoxon (POX) both in vitro and in vivo. This study evaluates MCP-conferred protection of enzyme activity head to head against the therapeutic gold standard pralidoxime (PRX). Six groups of rats were used. All substances were applied i.p. daily for 5 days, followed by a 2-day rest. The 7-day cycle was repeated eight times. Group 1 received 100 nM POX, group 2 received 50 micro M MCP, group 3 received 100 nM POX + 50 micro M MCP, group 4 received 50 micro M PRX, group 5 received 100 nM POX + 50 micro M PRX and group 6 received saline. Red blood cell acetylcholinesterase (RBC-AChE) measurements were performed at baseline and on day 5 of each 7-day cycle. The sums of enzyme activities over time (weekly values expressed as % of baseline of 100%) were compared using the Mann-Whitney rank order test. A Bonferroni correction of 4 for multiple comparisons was applied. Paraoxon significantly reduced enzyme activities when compared with saline (Sigma = 535 +/- 25 vs 902 +/- 42). Metoclopramide conferred statistically significant in vivo protection from inhibition of RBC-AChE by POX (Sigma = 640 +/- 58). The extent of protection was significantly less than that conferred by the gold standard PRX (Sigma = 765 +/- 57). Metoclopramide, in addition to being less effective as an RBC-AChE protective agent, also caused a failure to thrive in the POX+MCP-exposed rats, as evidenced by the changes in body weight.

Acetylcholinesterase↗
PubMedDate not supplied

The impact of vitamin C on diabetes induced alterations at murine neuromuscular junction.

Physiological functions of skeletal muscle are compromised in diabetes. This may involve free radical mechanisms and may be reversed by antioxidants. We have studied effects of vitamin C on twitch tension, resting membrane potential (RMP) and miniature endplate potentials (MEPPs) frequencies in dorsiflexor muscle of diabetic murine. Forty mice were divided randomly into 2 groups (n = 20 each). One group served as control and the other was injected once with streptozotocin (STZ) solution (60 mg/kg, i.p.) to induce diabetes. The animals were then divided further into two subgroups (n = 10 each). Vitamin C (200 mg/kg, i.p.) was administered daily to one control and one diabetic group for three weeks prior to recording day. Experiments were conducted four weeks following diabetes induction. Isometric twitch tension (evoked directly by muscle stimulation and indirectly by nerve stimulation) was measured in urethane anesthetized (2 mg/g, i.p.) mice via a transducer connected to computer system. Utilizing intracellular recording method, resting membrane potential RMP and MEPPs frequencies were also measured. Compared to control, diabetic mice showed reduced twitch tension (4.2 +/- 0.5 g control versus 2.6 +/- 0.2 g diabetic) and demonstrated delayed half time of decay. Diabetic flexor muscle also displayed significant reduction in MEPPs frequencies with no changes in RMP. Vitamin C reversed tension reduction in diabetic mice (from 2.6 +/- 0.2 g to 3.9 +/- 0.3 g), impacted delayed half time of decay and increased MEPPs frequencies. Vitamin C improves diabetes-induced nerve and muscle dysfunction possibly via a free radical scavenging mechanism.

Animals↗