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Biomedical subjects

J Ahmed

Publications and source records attributed to J Ahmed.

At least 37 records · Page 2Linked to original sources

Spinal intramedullary cysticercosis in a five-year-old child: case report and review of the literature.

Spinal intramedullary cysticercosis is rare and usually afflicts adults. We report the case of a 5-year-old Mexican girl with back pain who had a complex thoracic spinal intramedullary mass on magnetic resonance imaging and a positive immunoblot for Taenia solium. Surgery revealed a cystic mass containing a cysticercus. Cysticercosis should be suspected as the cause of an intramedullary spinal mass in a patient from an endemic area.

Anti-Bacterial Agents↗

Sexually transmitted infections among married women in Dhaka, Bangladesh: unexpected high prevalence of herpes simplex type 2 infection.

OBJECTIVES: To document the prevalence of reproductive tract infections (RTI) and sexually transmitted infections (STI) among women attending a basic healthcare clinic in Dhaka, Bangladesh, to identify risk factors associated with the diseases and to estimate the incidence of syphilis, hepatitis C (HCV), hepatitis B (HBV), and herpes simplex type 2 (HSV-2) infection. METHODS: A cross sectional sample of 2335 consecutive women was examined during 1996-8. Women were interviewed about risk factors for RTI/STI and tested for Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Treponema pallidum, HIV, HCV, HBV, HSV-1 and HSV-2 infection as well as vaginal candidosis and bacterial vaginosis. Women with antibodies to T pallidum were retested at regular intervals. One year after ending the study seroconversion for syphilis, HBV, HCV, and HSV-2 infection was detected among women initially negative for the respective diseases. RESULTS: The overall prevalence rate of N gonorrhoeae, C trachomatis, T vaginalis, and T pallidum infection was 0.5%, 1.9%, 2.0%, and 2.9% respectively. Overall, 35% of the women had antibodies to hepatitis B core antigen, 0.9% had HCV, and 12% HSV-2 infection. Risk factors for gonorrhoea/C trachomatis infection were a husband not living at home or suspected of being unfaithful. HSV-2 infection was associated with the same risk factors and with a polygamous marriage. The prevalence of HSV-2 infection among women "at risk" was 23%. HIV infection was not diagnosed. Repeated serological examination indicated that only 32% of women with serological evidence of syphilis had active disease. The seroincidences of HBV, HCV, and HSV-2 were 0.03, 0.007, and 0.009 per person year. Seroconversion for syphilis was not observed.

Adolescent↗

Reference value of immunoglobulins in healthy school children of Bangladesh.

The reference value of immunoglobulins (Igs) should be known for a population concerned because it is influenced by many clinical and local conditions. As yet the reference value of the Igs have not been determined in Bangladeshi children. This study determined the reference value of Igs in apparently healthy 261 rural Bangladeshi primary school children (aged 5 to 14 years, mean 9.3 years). IgG, IgM and IgA were determined by an auto-analyzer. The mean (standard deviation) value of IgG was 1728 (344) mg/dl. The corresponding values for IgM and IgA were 200 (88) and 163 (63) mg/dl, respectively. The 95% reference value calculation in all subjects showed that the range for IgG was 1103 to 2524, IgM was 92 to 390, and IgA was 72 to 325 mg/dl. These values could be used to evaluate Ig status in children with a variety of clinical conditions.

Adolescent↗

Design of a pressurization chamber for recordings of retinal blood flow in the "in vivo eyecup" preparation in the rat.

One major goal in our laboratory is development of an "in vivo eyecup" preparation in the rat. This preparation, which involves removal of the cornea and lens, maintains the normal vascular supply of the retina while allowing introduction of pharmacological agents into the medium that bathes this organ. Since we are interested in measuring retinal blood flow, it is sometimes necessary to repressurize the eye to maintain normal perfusion pressure across the retinal vasculature. The goal of this project was to develop a mechanism that allows repressurization of the in vivo eyecup after removal of the front of the eye. The basic design of this chamber consists of an eye ring to mechanically stabilize the eye and a pressurization chamber that attaches to this eye ring. The eye ring is connected to a base via a double hinged arm and can be locked in place. The pressurization chamber is attached to the top of this ring and sealed using an O-ring with a pressure fit. The top of the pressure chamber is composed of a clear polymer, allowing for photic stimulation of the retina, as well as introduction of laser light for blood flow determination. The pressure within the chamber is regulated by an elevated fluid-filled reservoir.

Animals↗

Metastatic cervical cancer with unusual presentation: a case report.

Carcinoma of the cervix is rare in the United States thanks to widespread use of screening Pap smears. A 60-year-old female with right upper quadrant pain, diarrhea, and urinary incontinence was found to have stage IV B cervical cancer. Computerized tomography (CT) was of value in diagnosis. Like mammography, which improves survival by detecting malignant disease at an early stage, the Pap test is central in preventing the development of invasive cervical cancer.

Abdominal Pain↗

The continuing risk of domestic hot water scalds to the elderly.

Elderly people are particularly at risk of accidents in the home and with an ageing population, they constitute a large proportion of scald victims. We have seen several elderly patients every year in our own unit who had sustained domestic hot water burns. We decided to ascertain the temperature of water in the private homes of elderly people and in residential care homes in our community. Twenty-five private homes and 14 residential care homes were visited and peak water temperatures were measured in the kitchens and bathrooms. Only one private home and one residential home had water below 45 degrees C. It is recommended that water should be delivered at less than 43 degrees C. We conclude that water is dangerously hot. However, if water is stored at a temperature of less than 60 degrees C there is a risk of infection with Legionella pneumophila. Existing regulations governing the use of 'fail safe' thermostatic mixing devices must be enforced and extended to cover domestic hot water systems.

Accidents, Home↗

Potential of rice husks for antimony removal.

The adsorption behavior of rice husks for antimony ions from aqueous solutions has been investigated as a function of appropriate electrolyte, equilibration time, hydrogen ions, amount of adsorbent, concentration of adsorbate, effect of diverse ions and temperature. The best conditions in which this material can be used as adsorbent have been explored. The radiotracer technique was employed to determine the distribution of antimony (122Sb) using a batch method. Maximum adsorption was observed at 0.01 mol L(-1) acid solutions (HNO3, HCl, H2SO4 and HClO4) using 1.0 g of adsorbent for 1.92 x 10(-5) mol L(-1) antimony concentration in 10 min equilibration time. Studies show that the adsorption decreases with the increase in the concentrations of all the acids. The adsorption data follow the Freundlich isotherm over the range of 1.92 x 10(-5) to 2.05 x 10(-4) mol L(-1) antimony concentration. The characteristic Freundlich constants i.e., 1/n = 0.82 +/- 0.05 and K = 4.61 +/- 0.07 m mol g(-1) have been computed for the sorption system. The uptake of antimony increases with the rise in temperature (299-323 K). Thermodynamic quantities i.e., deltaG0, deltaS0 and deltaH0 have also been calculated for the system. The sorption process was found to be endothermic.

Journal Article↗

Erythrocyte sedimentation rate in healthy school children of Bangladesh.

The reference value of erythrocyte sedimentation rate (ESR) should be established for a population concerned because it is influenced by many local conditions. It has not yet been determined in healthy children of Bangladesh. This study was done to determine the reference value of ESR in Bangladeshi children. ESR was determined in a sample of 413 'healthy' primary school students (259 boys and 154 girls, mean age 8.7 years). Ninety-five percent of them had ESR < or = 30 mm (Westergren 1 h). Our findings suggest that ESR value > 30 mm (Westergren 1 h) should be considered high in Bangladeshi primary school children.

Adolescent↗

Coronary arteriovenous fistula with papillary muscle rupture.

We describe a patient who had a coronary arteriovenous fistula (CAVF) and whose mitral valve papillary muscle ruptured from chronic ischemia due to a coronary steal phenomenon. He was treated surgically with ligation of the CAVF (left circumflex to coronary sinus), coronary artery bypass grafting, and mitral valve replacement. This is the first report of papillary muscle rupture related to CAVF.

Arteriovenous Fistula↗

Decoherence in electron backscattering by kinked dislocations.

A model is proposed that explains the origin of the bright contrast of dislocation walls consisting of edge dislocation dipoles in electron channelling contrast images (ECCI) of fatigued crystals, when the incident beam is parallel to the edge dislocations. The model is based on the assumption that the contrast arises from the dislocation segments terminating the dipoles. These are modelled as screw-type kinks which scatter electrons. Scattering by randomly distributed kinks leads to the randomization of phase of transmitted and diffracted beams and suppresses the anomalous transmission of electrons. The predicted behaviour of electron-channeling contrast images agrees well with experimental observations.With apologies for using two beams instead of three!

Journal Article↗

Identifying inner retinal contributions to the human multifocal ERG.

Contributions to the multifocal electroretinogram (ERG) from the inner retina (i.e. ganglion and amacrine cells) were identified by recording from monkeys before and after intravitreal injections of n-methyl DL aspartate (NMDLA) and/or tetrodotoxin (TTX). Components similar in waveform to those removed by the drugs were identified in the human multifocal ERG if the stimulus contrast was set at 50% rather than the typically employed 100% contrast. These components were found to be missing or diminished in the records from some patients with glaucoma and diabetes, diseases which affect the inner retina.

Adult↗

Study of dislocation structures near fatigue cracks using electron channelling contrast imaging technique (ECCI).

The fatigue of copper single crystals, orientated for single slip, has been studied using electron channelling contrast imaging in a scanning electron microscope. With the incident beam set at the Bragg condition, changes in the backscattered electron intensity occur as the beam is scanned over dislocations that cause a local tilting of the diffraction planes. This technique allows the evolution of dislocation structures over large areas to be followed through different stages of the fatigue life. Furthermore, it enables direct imaging of dislocation configurations at crack tips. The technique is compared with transmission electron microscopy and electron backscatter diffraction in its application to fatigue studies.

Journal Article↗

Humoral immune response in a sample of Bangladeshi children with rheumatic fever.

Several researchers have investigated cellular response, and antibody response to different antigens of group A beta-haemolytic streptococci, cardiac tissues and B cell alloantigen in rheumatic fever (RF). However, immunoglobulins (Ig) which may indicate general immune status did not receive attention. This study was done in the outpatient clinic of the National Center for Control of Rheumatic Fever and Heart Diseases, Dhaka, to compare Ig levels in subjects with and without RF who have had recent group A beta-haemolytic streptococcal infections. We have recruited 44 RF cases aged 5 to 20 years, and 44 subjects without RF were randomly matched for age and sex as controls. Convalescent blood samples were used to measure antistreptolysin O and IgG, IgM, and IgA levels. The cases, as compared with the controls, had significantly higher levels of antistreptolysin O (mean 399 versus 321 IU/ml), IgG (mean 2386 versus 1885 mg/dl), IgM (mean 286 versus 222 mg/dl) and IgA (mean 258 versus 184 mg/dl). It is not clearly known why the immune response is higher in the RF cases. We have to elucidate factors responsible for higher immune response in children with RF.

Adolescent↗

Retinal hypoxia in long-term diabetic cats.

PURPOSE: To determine whether the retina is hypoxic in early stages of diabetic retinopathy in cats and to correlate intraretinal PO2 with fluorescein angiographic and histologic alterations. METHODS: Intraretinal PO2 was measured with microelectrodes in three cats with long-standing diabetes (>6 years) that had been followed with fluorescein angiographs every 6 months. Average PO2 in the inner vascularized half of the retina was compared with similar measurements in 21 control animals. Photoreceptor oxygen consumption was also compared. The retinal vascular endothelium of the diabetic animals was stained for ADPase activity in flatmounts, and transverse sections were used to visualize microscopic alterations in vascular structure. RESULTS: PO2 in the inner half of the retina was abnormally low in the diabetic cats, 7.7+/-5.2 mm Hg (35 penetrations in 3 cats) versus 16.4+/-9.3 mm Hg in normal cats (85 penetrations in 21 cats) (P << 0.001). Oxygenation was almost normal in some regions of the diabetic retinas, but little evidence of oxygen supply from the retinal circulation was observed in other regions. Inner retinal hypoxia was present in areas with no detectable capillary dropout in fluorescein angiograms or flatmounts. The worst changes histologically were microaneurysms, leukocyte and platelet plugging of aneurysms and venules, and degenerating endothelial cells in capillary walls. These histologic abnormalities were confined to small regions, some of which could be positively correlated with markedly abnormal PO2 profiles. Photoreceptor oxygen utilization was not affected in two diabetic cats, but was below normal in one animal in which choroidal PO2 was low. CONCLUSIONS: This is the first direct demonstration of retinal hypoxia in early diabetic retinopathy, before capillary dropout was evident clinically. Hypoxia was correlated with endothelial cell death, leukocyte plugging of vessels, and microaneurysms.

Animals↗