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Biomedical subjects

S M Ahmed

Publications and source records attributed to S M Ahmed.

At least 19 recordsLinked to original sources
PubMed2006

INDO/SCF-CI calculations and structural spectroscopic studies of some complexes of 4-hydroxyacetanilide.

The electronic energies among different possible structures of 4-hydroxyacetanilide (paracetamol) (PA) molecule, were calculated using INDO method and it has been concluded that its structure has C(s) point group symmetry of the cis-form. The ionization potential, electron affinity, dipole moment and binding energy have been calculated. The calculated electronic transitions of the cis-form of PA using SCF-CI method have good coincidence with the electronic absorption spectrum. The temperature effect on the electronic spectrum of PA confirms the presence of one conformer only. The electronic spectra of PA compound were studied in different polar- and non-polar solvents and the hydrogen bonding as well as the orientation energies of the polar solvents were determined from the mixed solvents studies. Complexes of PA with various metal ions such as, Cu(II), Zn(II) or Fe(II) ions of ratio 2:1, respectively, have been prepared and their structure has been confirmed by elemental analysis, atomic absorption spectra, IR spectra and (1)H NMR spectra and finally it can be concluded that the structure of the complexes has C2h point group symmetry in which two PA molecules are chelated to any one of the metal ions, Cu(II), Zn(II) and Fe(II) ions.

Acetaminophen↗
PubMed2006

Early outcomes of coronary artery bypass with and without cardiopulmonary bypass in octogenarians.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) surgery has been successfully used in diverse patient populations and has been postulated to be safer than conventional coronary artery bypass (CCAB) surgery in some high-risk patients, including the elderly. OBJECTIVE: To compare the safety of OPCAB surgery versus CCAB surgery in the octogenarian population of two large southwestern Ontario cardiac surgical units. RESULTS: Two hundred thirty-six consecutive octogenarians underwent primary isolated coronary artery bypass surgery from November 2000 to March 2005. Patients undergoing OPCAB surgery tended to have higher Parsonnet scores, while patients undergoing CCAB surgery had a greater number of emergent operations. The Canadian Cardiovascular Network predicted that mortality risk was similar in both groups. In-hospital mortality was similar between groups, as was postoperative myocardial infarction and new onset of renal dysfunction. However, in the OPCAB group, there was a decreased incidence of postoperative neurological dysfunction (2.3% in the OPCAB group versus 10.5% in the CCAB group, P=0.01), in particular cerebrovascular accidents (1.5% in the OPCAB group versus 7.6% in the CCAB group, P=0.05), and a decreased incidence of prolonged intubation (5.3% in the OPCAB group versus 13.3% in the CCAB group, P=0.04). Multivariable analysis found that cardiopulmonary bypass had no significant impact on mortality or length of stay. CONCLUSIONS: In octogenarian patients, OPCAB surgery is as safe as CCAB surgery in terms of mortality and major morbidity. Furthermore, a significant reduction in neurological dysfunction and prolonged intubation was seen in the OPCAB group compared with the CCAB group.

Aged, 80 and over↗
PubMed2006

Quantitative determination of four constituents of Tinospora sps. by a reversed-phase HPLC-UV-DAD method. Broad-based studies revealing variation in content of four secondary metabolites in the plant from different eco-geographical regions of India.

This paper describes the separation and quantitation of important markers, such as 20beta-hydroxyecdysone, tinosporaside, cordioside, and columbin, present in three species of Tinospora viz, T. cordifolia, T. malabrica, and T. crispa. A reverse-phase (RP) high-performance liquid chromatography (HPLC)-UV-diode array detection (DAD) method employing gradient elution is thus developed. The marker compounds isolated from 70% ethanolic extract of T. cordfolia by repeated column chromatography are identified on the basis of (1)H NMR, (13)C NMR, and mass spectral data. The compounds are separated on a RP (RP-18, 5 microm, 250 x 4.6-mm i.d.) column using water-acetonitrile gradient and are detected by the HPLC-UV-DAD method. The calibration curves that result from marker compounds in the concentration range of 100-2000 ng on column exhibit a good correlation (r(2) > or = 0.99978). The method is successfully applied to separate and study the content of four marker compounds in 40 different accessions of three Tinospora species collected from different regions of India. The studies reveal that the maximum amount of the marker compounds is present in Tinospora cordifolia species, especially from accessions collected from higher altitudes of the Jammu province (North India).

Calibration↗
PubMed2005

Proniosomes as a drug carrier for transdermal delivery of ketorolac.

Niosomes are nonionic surfactant vesicles that have potential applications in the delivery of hydrophobic and hydrophilic drugs. Permeation of a potent nonsteroidal anti-inflammatory, ketorolac, across excised rabbit skin from various proniosome gel formulations was investigated using Franz diffusion cells. Each of the prepared proniosomes significantly improved drug permeation and reduced the lag time (P<0.05). Proniosomes prepared with Span 60 provided a higher ketorolac flux across the skin than did those prepared with Tween 20 (7- and 4-fold the control, respectively). A change in the cholesterol content did not affect the efficiency of the proniosomes, and the reduction in the lecithin content did not significantly decrease the flux (P>0.05). The encapsulation efficiency and size of niosomal vesicles formed by proniosome hydration were also characterized by specific high performance liquid chromatography method and scanning electron microscopy. Each of the prepared niosomes achieved about 99% drug encapsulation. Vesicle size was markedly dependent on the composition of the proniosomal formulations. Proniosomes may be a promising carrier for ketorolac and other drugs, especially due to their simple production and facile up.

Administration, Cutaneous↗
PubMed2005

Effect of aerobic exercise on patients with primary fibromyalgia syndrome.

Sixty eight adult patients of fibromyalgia were included in this prospective study from the Outpatient Department of Physical Medicine and Rehabilitation of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka during the period of January 2003 to June 2003. Study samples were assigned into two treatment groups: Group A (n = 38) with exercise by static bicycle and aerobic walking in addition to tricyclic antidepressant and analgesic and Group B (n = 30) was non exercise group, treated with tricyclic antidepressant and analgesic only. The total duration of treatment was 16 weeks. Pre-treatment (week 0) and post treatment (week 16) evaluation was performed in both groups. Evaluation parameters included pain grade, number of trigger points, occurrence of arousal at night, frequency of micturition and global evaluation by the physician. After 16 weeks, mean improvement of exercise group and non exercise group was 48% and 39% respectively but this difference was not statistically significant. Therefore, from this study it was observed that aerobic exercise showed no significant benefit to fibromyalgia patients.

Exercise↗
PubMed2004

NR2B selective NMDA receptor antagonist CP-101,606 prevents levodopa-induced motor response alterations in hemi-parkinsonian rats.

Sensitization of NMDA receptors containing the NR2B subunit has been increasingly associated with various forms of synaptic plasticity, including those implicated in the pathogenesis of extrapyramidal motor dysfunction. To determine whether activation of NR2B containing receptors contributes to the development and maintenance of levodopa-induced response changes in parkinsonian animals, we evaluated the effects of the selective NR2B antagonist CP-101,606 on these response alterations in unilateral 6-hydroxydopamine (6-OHDA) lesioned rats. Three weeks of twice-daily levodopa treatment decreased the duration of the rotational response to acute levodopa challenge. The response alteration was associated with an increase in GluR1 (S831) phosphorylation in medium spiny neurons of the dorsolateral striatum. Both the attenuated rotational response and augmented GluR1 phosphorylation were decreased by CP-101,606 treatment. These CP-101,606 effects were observed when the compound was administered either at the end of chronic levodopa treatment (ameliorative effect) or together with the twice-daily levodopa treatment for 3 weeks (preventive effect). Furthermore, concurrent administration of CP-101,606 with levodopa potentiated the ability of levodopa challenge to reverse the 6-OHDA lesion-induced contralateral forelimb movement deficit as measured in a drag test. These results suggest that activation of NR2B subunit containing NMDA receptors contributes to both the development and maintenance of levodopa-induced motor response alterations, through a mechanism that involves an increase in GluR1 phosphorylation in striatal spiny neurons.

Animals↗
PubMed2003

Effects of alkali and simulated gastric and intestinal fluids on danazol stability.

The degradation kinetics of methanolic solution of danazol (0.020% w/v) in aqueous buffers and sodium hydroxide was investigated using stability-indicating HPLC method. The drug degrades in alkaline medium through a base-catalysed proton abstraction rather than via an oxidative mechanism involving oxygen species. The degradation followed pseudo-first-order kinetics. The rates pH-profile exhibited specific base catalysis. The stability of the drug was found to be dependent on pH, buffer concentration, buffer species (acetate, borate, phosphate) and temperature. The ionic strength did not affect the stability of the drug. The energy of activation according to Arrhenius plot was estimated to be 22.62 kcal mol(-1) at pH 12 and temperatures between 30 and 60 degrees C. The effect of simulated gastric and intestinal fluids on the drug stability was also investigated. Two major hydrolytic degradation products were separated and identified by IR, NMR and mass spectrometry and the degradative pathway suggested.

Alkalies↗
PubMed2003

A comparison of the laryngeal mask airway and PA(Xpress) for short surgical procedures.

Sixty adult patients undergoing minor peripheral surgery under general anaesthesia were randomly allocated to receive either the laryngeal mask airway (laryngeal mask airway; size 4 for females and size 5 for males) or the PAXpress (adult size), inserted by a single operator with experience of > 50 insertions of each device. The laryngeal mask airway was correctly placed on the first attempt in 27 patients (90%) compared with 20 patients (67%) when using the PAXpress (p < 0.01). No patient required more than two attempts at insertion and there were no failures with the laryngeal mask airway, compared with four (13%) who needed three attempts and two failures (7%) with the PAXpress (p < 0.001 and p < 0.01, respectively). Mean (SD) total placement time was shorter with the laryngeal mask airway [24.6 (3.1) s] than with the PAXpress[35.4 (2.5) s; p < 0.01]. The most common complication was sore throat, which occurred less frequently with the laryngeal mask airway (8 patients; 26%) than with the PAXpress (15 patients; 53.5%; p < 0.001).

Adult↗
PubMed2002

Kinetics of solid state stability of glycine derivatives as a model for peptides using differential scanning calorimetry.

Kinetics of solid state stability of seven derivatives of 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) of glycine as a model for amino acids and peptide drugs were studied using differential scanning calorimetry (DSC). Each DSC curve for each derivative showed an endothermic peak followed by an exothermic one, which could be attributed to the melting and decomposition, respectively. The decomposition activation energy of each derivative was calculated using the Augis and Bennet, Kissinger equations and Mahadevan approximation. Also, the melting activation energies as well as the thermodynamic parameter (enthalpy) for the investigated derivatives were evaluated. The relative stability of the derivatives in the solid state according to the calculated values of the decomposition activation energy, frequency factors and half-life for each derivative could be determined.

Calorimetry, Differential Scanning↗
PubMed2002

The cellular response associated with cervical intraepithelial neoplasia in HIV+ and HIV- subjects.

This study investigates local alterations in T-cell and macrophage subsets that occur in cervical epithelial neoplasia (CIN), in the presence and absence of human immunodeficiency virus (HIV) infection. Ectocervical biopsies from 10 women with CIN who were infected with HIV, and 10 women with CIN but no HIV infection were studied by immunocytochemistry. Significantly increased proportions of activated CD8+ T cells were seen in all CIN biopsies, and these proportions were further increased in the presence of HIV infection. Levels of CD8+TIA-1+ cells were particularly increased in the CIN+HIV+ group. There was a lack of expression of CD28 on the CD8+ cells of the epithelium of CIN+HIV+ samples. A significant reduction in the proportion of epithelial inductive D1+ macrophages and an increase in D1+D7+-suppressive cells were observed in the CIN+HIV+ cohort. The lack of expression of CD28 on the CD8+ cells of the epithelium of CIN+HIV+ samples in combination with the reduced CD4+ T-cell numbers seen in the presence of HIV infection may contribute to the development of higher grade CIN in this susceptible group. This may be aggravated by the reduction in the D1+ epithelial inductive macrophages, which might reflect recruitment of more suppressive D1+D7+ cells. This would further compromise the ability of the local T-cell system to respond to antigens and thus contribute to the development of neoplasia at this site. These results suggest that the increase in activated CD8+ T cells is a consequence rather than a cause of CIN.

Adolescent↗
PubMed2002

Hormone replacement therapy and malignant melanoma: to prescribe or not to prescribe?

The mean age of presentation of malignant melanoma in women is the early fifties, a time that may be concomitant with the onset of the menopause. As the lesion can often be successfully surgically excised, many women will enter the menopause disease-free but in need of treatment for their menopausal symptoms. Melanoma has traditionally been considered to be an estrogen receptor-positive tumor, whose prognosis is adversely affected by estrogen, whether during pregnancy or in association with the oral contraceptive pill or hormone replacement therapy (HRT). Recent evidence now refutes this. As most recurrences occur in the first 2 years following treatment, it may be prudent to defer HRT until this time. There is a particular paucity of information pertaining to HRT and melanoma, such that, at present, there appears to be no justification for withholding this potentially beneficial therapy from menopausal women who have undergone treatment for melanoma.

Diagnosis, Differential↗
PubMed2001

Barriers to healthcare access in a non-elderly urban poor American population.

An understanding of perceived barriers to health-care is critical to improving healthcare access for all Americans. To determine perceived barriers to health-care in an urban poor population in Dayton, Ohio, a face-to-face door-to-door survey of individuals identified through targeted, stratified, area probability sampling was done. A sample of 413 non-elderly poor adults, including 19% without telephones, reported personal relevance of various barriers to healthcare access. Most frequently endorsed barriers were lack of information about free or reduced-cost health-care, anticipated cost, and difficulty accessing child-care. Seventy-four per cent of respondents reported more than one barrier. Individuals without telephones and those without health insurance reported more barriers to health-care. Reported barriers were similar for working and non-working poor, except for transportation problems, more frequently reported by non-working respondents. This study provides important data on what poor people in a medically underserved community perceive to be barriers to accessing health-care and underscores the importance of including people without telephones in the study design. Respondents who did not have telephones were more likely to report multiple barriers, particularly problems with lack of information about free or discounted medical care, child-care, and transportation. These findings suggest the importance of door-to-door surveys rather than telephone surveys for getting accurate data on the poor.

Adolescent↗
PubMed2001

Differing health and health-seeking behaviour: ethnic minorities of the Chittagong Hill Tracts, Bangladesh.

This study investigates the health and health-seeking behaviour of the indigenous population of Chittagong Hill Tracts, Bangladesh by surveying 2,550 randomly selected households from five major ethnic groups residing in the region. A structured questionnaire was used for collecting data. Morbidity prevalence (23%) and child malnutrition (19%) was highest among Bangalis. Fever (40%), diarrhoeal diseases (37%) and malaria (16%) were the three most common illnesses reported among the study population. Around fifteen percent of the Bangalis sought care from the paraprofessionals while 'unqualified' allopaths were consulted more frequently by the Tripuras, Chakmas and the Marmas (60-70%). Qualified allopaths were mostly consulted by the Bangalis (26%). Sex, types of illness, ethnicity, household head's education and household's landholding were significant predictors of seeking treatment, and allopathic treatment in particular. The findings on the differential health and health-seeking behaviour among ethnic groups should help in the designing of any future health interventions in the area.

Adolescent↗
PubMed2001

Incidence of uterine rupture in a Teaching Hospital, Sudan.

OBJECTIVE: This study aims to document the experience of uterine rupture as a serious common complication of pregnancy in some developing countries like Sudan. The study is also aimed at reviewing the main contributing factors so as to draw broad lines for a strategy of prevention. METHODS: A retrospective study carried out at Medani Teaching Hospital, Medani City, Sudan. Case notes were reviewed for all patients with uterine rupture from 1st January 1992 through 31st of December 1997. The data was analyzed and the literature was reviewed to compare the results of similar studies. RESULTS: Out of the total number of deliveries in that period (n=21190), 86 cases were diagnosed to have uterine rupture giving an incidence of 1:246. The main contributing factor to uterine rupture identified in this study, was poor ante-natal care (64%). One most important direct cause of uterine rupture was previous cesarean section scar with or without cephalopelvic disproportion (n=39) (45%). Seventy-six cases, had complete rupture of uterus. Subtotal hysterectomy was carried out on 69 cases (80%) and 15 cases (17%) had uterine repair with bilateral tubal ligation. Three patients developed vesico vaginal fistula (3.5%). The ureter was iatrogenically severed in 2 cases (2%). There were 6 (7%) maternal deaths and 68 (79%) perinatal deaths. CONCLUSION: This study confirms the existence of a serious preventable obstetrical problem. Poor antenatal care, poor provision of health service and low socioeconomic standards, are the main factors contributing to uterine rupture. Those findings would suggest that both social and medical improvements will significantly improve survival in mothers with ruptured uterus and reduce the perinatal loss.

Adult↗
PubMed2001

Effect of tetrodotoxin (TTX) on some brain neurotransmitters in rats.

Tetrodotoxin (TTX) is a potent marine neurotoxin named after the order of fish from which it is most commonly associated, the Tetraodontiforms, or the tetraodon pufferfish. In the present study the crude TTX was extracted from pufferfish Lagocephalus sceleratus collected from the Red Sea in Egypt. The LD100 and LD50 of crude TTX were found to be 8.33 and 6.26 mg/kg for the gonad extract and 41.8 and 27.9 mg/kg for the skin extract, respectively. This indicates that the gonad TTX is more lethal than the skin. The effects of both gonad and skin TTX extracts on the levels of brain serotonine, acetylcholine, histamine, norepinephrine, and epinephrine were studied in rats. Brain serotonine level was significantly increased and reached its peak level after 4 hours (P<0.001) of TTX administration. Brain acetylcholine, histamine, and norepinephrine levels were also significantly increased but reached peak level after 6 hours (P<0.001). The effect of the gonad extract was more significantly profound and of longer duration than the skin extract. On the other hand, brain epinephrine did not show any significant change during the experimental period.

Animals↗