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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
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↗
PubMed2000

A simple kinetic spectrophotometric method for the determination of oxamniquine in formulations and spiked biological fluids.

A simple and sensitive kinetic method for the determination of oxamniquine in pharmaceutical preparations and biological fluids was developed. The procedure is based upon a kinetic investigation of the oxidation reaction of the drug with alkaline potassium permanganate at room temperature for a fixed time of 20 min. The absorbance of the colored manganate ions was measured at 610 nm. Alternatively, the decrease in the absorbance of potassium permanganate after addition of the drug was measured at 525 nm. The absorbance concentration plots in both procedures were rectilinear over the range 0.5-4 microg ml(-1). The concentration of oxamniquine is calculated using the corresponding calibration equation for the fixed-time method. The determination of oxamniquine by fixed-concentration and rate-constant methods was feasible with the calibration equations obtained but the fixed time method had been found to be more applicable. Both procedures were applied to the determination of oxamniquine in formulations. The results obtained were in good agreement with those obtained using the official method. The fixed time method of 20 min was further applied to spiked human urine and plasma, the recoveries (%) were 100.94 +/- 0.57 and 98.07 +/- 0.88 for urine and plasma, respectively, at 610 nm, and 97.51 +/- 1.27 and 95.69 +/- 1.23 for urine and plasma, respectively, at 525 nm.

Body Fluids↗
PubMed2000

Gender, socioeconomic development and health-seeking behaviour in Bangladesh.

In efforts to reduce gender and socioeconomic disparities in the health of populations, the provision of medical services alone is clearly inadequate. While socioeconomic development is assumed important in rectifying gender and socioeconomic inequities in health care access, service use and ultimately, outcomes, empirical evidence of its impact is limited. Using cross-sectional data from the BRAC-ICDDR,B Joint Research Project in Matlab, Bangladesh, this paper examines the impact of membership in BRAC's integrated Rural Development Programme (RDP) on gender equity and health-seeking behaviour. Differences in health care seeking are explored by comparing a sample of households who are BRAC members with a sample of BRAC-eligible non-members. Individuals from the BRAC member group report significantly less morbidity (15-day recall) than those from the non-member group, although no gender differences in the prevalence of self-reported morbidity are apparent in either group. Sick individuals from BRAC member households tend to seek care less frequently than non-members. When treatment is sought, BRAC members rely to a greater extent on home remedies, traditional care, and unqualified allopaths than non-member households. While reported treatment seeking from qualified allopaths is more prevalent in the BRAC group, non-members use the para-professional services of community health care workers almost twice as frequently. In both BRAC member and non-member groups, women suffering illness report seeking care significantly less often than men. The policy and programmatic implications of between group and gender differences in care seeking are discussed with reference to the literature.

Adolescent↗
PubMed2000

LC assay method for oxfendazole and oxyclozanide in pharmaceutical preparation.

A method has been developed for the simultaneous determination of oxfendazole and oxyclozanide in a pharmaceutical preparation. The method involves reversed phase chromatography with isocratic elution of the mobile phase and detection at 300 nm. The range of quantification for oxfendazole and oxyclozanide was found to be 2-7 microg ml(-1) and 3-10 microg ml(-1), respectively. The validity of the method was evaluated in terms of linear regression analysis, precision, specificity and accuracy.

Antiplatyhelmintic Agents↗
PubMed2000

ECG data compression using optimal non-orthogonal wavelet transform.

This paper introduces an effective technique for the compression of electrocardiogram (ECG) signals. The technique is based on a new class of non-orthogonal discrete wavelet transform (DWT). The performance of ECG compression algorithm is measured by its ability to minimize distortion while retaining all clinically significant features of the signal. The percent root-mean square difference (PRD) is used as an accepted standard for measuring the signal distortion. However, there is no standard for measuring the clinically significant features retained after signal reconstruction. The coefficients of the DWT are calculated such that the square of the difference between the original signal and the reconstructed one is minimum in least mean square sense. The resulting transforms deal with signals of arbitrary lengths; that means the signal length is not restricted to be a multiple of power of 2. Numerical results comparing the performance of the constructed non-orthogonal transform with that of W-transform and Daubechies D(4) orthogonal transform are given. These results show that, independent of signal length, the decomposition of the signal up to the fourth level is sufficient for getting minimum PRD. In addition, the proposed technique yields the lowest PRD compared to the other two algorithms and for a compression ratio less than 10 the optimal transform can be obtained for only one ECG period. However, for a higher compression ratio the PRD is smaller for long signals.

Algorithms↗
PubMed2000

"The history of health in Dayton": a community-academic partnership.

Academic institutions have always found it a challenge to persuade community members to participate in academic research projects. Starting an open dialogue is usually the critical first step. To begin this dialogue with community members in Dayton, Ohio, in 1999, staff from Wright State University decided to organize a community forum, "The History of Health in Dayton." The forum was intended as the first project of a new research organization, the Alliance for Research in Community Health (ARCH), established with federal funding from the Health Resources and Services Administration in 1998. ARCH was created as a bridge between the Department of Family Medicine of Wright State University School of Medicine and the Center for Healthy Communities, a health advocacy and service organization committed to health professions education. ARCH's mission is to improve the health of citizens of Dayton through research involving community participation. Through ARCH, community members help researchers define priorities, resolve ethical issues, refine procedures, and interpret results. Guidelines for participatory research, proposed by the National Primary Care Research Group in 1998 and adopted by the alliance, emphasize the importance of open dialogue among researchers, subjects, academics, and community members. The initial response to the forum was enthusiastic, with a majority of community residents expressing interest in attending future presentations.

Community Health Planning↗
PubMed2000

Stretch-induced injury alters mitochondrial membrane potential and cellular ATP in cultured astrocytes and neurons.

Energy deficit after traumatic brain injury (TBI) may alter ionic homeostasis, neurotransmission, biosynthesis, and cellular transport. Using an in vitro model for TBI, we tested the hypothesis that stretch-induced injury alters mitochondrial membrane potential (delta(psi)m) and ATP in astrocytes and neurons. Astrocytes, pure neuronal cultures, and mixed neuronal plus glial cultures grown on Silastic membranes were subjected to mild, moderate, and severe stretch. After injury, delta(psi)m was measured using rhodamine-123, and ATP was quantified with a luciferin-luciferase assay. In astrocytes, delta(psi)m dropped significantly, and ATP content declined 43-52% 15 min after mild or moderate stretch but recovered by 24 h. In pure neurons, delta(psi)m declined at 15 min only in the severely stretched group. At 48 h postinjury, delta(psi)m remained decreased in severely stretched neurons and dropped in moderately stretched neurons. Intracellular ATP content did not change in any group of injured pure neurons. We also found that astrocytes and neurons release ATP extracellularly following injury. In contrast to pure neurons, delta(psi)m in neurons of mixed neuronal plus glial cultures declined 15 min after mild, moderate, or severe stretch and recovered by 24-48 h. ATP content in mixed cultures declined 22-28% after mild to severe stretch with recovery by 24 h. Our findings demonstrate that injury causes mitochondrial dysfunction in astrocytes and suggest that astrocyte injury alters mitochondrial function in local neurons.

Adenosine Triphosphate↗