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Biomedical subjects

M Mohamed

Publications and source records attributed to M Mohamed.

At least 19 recordsLinked to original sources
PubMed2005

Patterns of genetic diversity and migration in increasingly fragmented and declining orang-utan (Pongo pygmaeus) populations from Sabah, Malaysia.

We investigated the genetic structure within and among Bornean orang-utans (Pongo pygmaeus) in forest fragments of the Lower Kinabatangan flood plain in Sabah, Malaysia. DNA was extracted from hair and faecal samples for 200 wild individuals collected during boat surveys on the Kinabatangan River. Fourteen microsatellite loci were used to characterize patterns of genetic diversity. We found that genetic diversity was high in the set of samples (mean H(E) = 0.74) and that genetic differentiation was significant between the samples (average F(ST) = 0.04, P < 0.001) with F(ST) values ranging from low (0.01) to moderately large (0.12) values. Pairwise F(ST) values were significantly higher across the Kinabatangan River than between samples from the same river side, thereby confirming the role of the river as a natural barrier to gene flow. The correlation between genetic and geographical distance was tested by means of a series of Mantel tests based on different measures of geographical distance. We used a Bayesian method to estimate immigration rates. The results indicate that migration is unlikely across the river but cannot be completely ruled out because of the limited F(ST) values. Assignment tests confirm the overall picture that gene flow is limited across the river. We found that migration between samples from the same side of the river had a high probability indicating that orang-utans used to move relatively freely between neighbouring areas. This strongly suggests that there is a need to maintain migration between isolated forest fragments. This could be done by restoring forest corridors alongside the river banks and between patches.

Animals↗
PubMed2005

Runoff quality and pollution loadings from a tropical urban catchment.

Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.

Agriculture↗
PubMed2002

Intestinal parasitic infection among five interior communities at upper Rejang River, Sarawak, Malaysia.

Intestinal parasitic infection among five interior communities at Bakun Valley, upper Rejang River, Sarawak, Malaysia, was investigated as part of a public health impact assessment of the proposed US$ 3 billion Bakun Hydroelectric Project. Coproparasitological examination of 355 stool samples from 7 of 16 villages representing 5 of 7 tribes in the area revealed infection rate of 41%. A higher infection rate was found among the settled Kayans (56%) than the seminomadic Penans (29%). Infection rate was high (68%) among children less than 14 years old. Trichuris trichiura accounted for more than 90% of all infections; less common were Ascaris lumbricoides, hookworms and Strongyloides stercoralis. Polyparasitism was found in 8% of the individuals surveyed with dual infection due to T. trichiura and A. lumbricoides being more common than dual infection with T. trichiura and hookworm. Women had higher infection rates (57%) than men (33%).

Adolescent↗
PubMed2002

Comparison of field measurements to predicted reaeration coefficients, k2, in the application of a water quality model, QUAL2E, to a tropical river.

Some of the many tools used for watershed management are mathematical and computer models for wasteload allocations. QUAL2E is one of the most popular water quality models used for such purposes. The question arises as to whether the model is applicable in a different climate such as that in the tropics. In this study, QUAL2E was used to model Sg. Selangor River in Malaysia using the predictive equations for reaeration coefficient (k2) within the model and the measured reaeration coefficients for the river. The study results indicated that use of the reaeration coefficient (k2) measured at Sg. Selangor River did give the lowest standard error (SE) for the simulation of water quality during the 7Q10 low-flow period which is considered as the worst scene scenario in water quality modeling. But during calibration and validation using actual low-flow discharge data, the measured reaeration coefficients did not give the lowest standard error (SE). In conclusion, the results indicated that QUAL2E is applicable in tropical rivers when used with the modeled river parameters (i.e. hydraulic parameters, meteorological conditions etc.). Measured reaeration coefficients produced good results and several predictive equations also produced comparatively good results.

Forecasting↗
PubMed2001

Machine perfusion for kidneys: how to do it at minimal cost.

Due to a shortage of organs for transplantation, many centres use marginal grafts to increase their donor pool. As kidneys from non-heart-beating donors (NHBD) have sustained initial ischaemic damage, their viability is difficult to predict. Hypothermic pulsatile perfusion has not only been used to improve the condition of such grafts, but also allows viability assessment. Suitable systems are becoming more readily available, but they are expensive. We have used existing dialysis equipment with modified sterilised inserts to create a pulsatile hypothermic perfusion system. With this system, 41 NHBD kidneys were perfused for up to 8 h; their intravascular renal resistance (IRVR), flow characteristics as well as glutathione S transferase (GST) measurements were performed to assess viability. This hypothermic pulsatile perfusion system is now an integral component of our NHBD programme.

Costs and Cost Analysis↗
PubMed2001

Aerosol particle and organic vapor concentrations at industrial work sites in Malaysia.

The objective of this study was to establish baseline data about air pollutants potentially related to nasopharyngeal carcinoma (NPC) in the Federal Territory and Selangor, Malaysia. During 1991-1993, ambient air quality was monitored at 42 work sites representing ten industrial sectors: adhesive manufacturing, foundries, latex processing, metalworking, plywood/veneer milling, ricemilling, rubber tire manufacturing, sawmilling, shoemaking, and textile related industries. At each work site, aerosol particle size distributions and concentrations of formaldehyde, benzene, toluene, isopropyl alcohol, and furfural were measured. Mean aerosol particle concentrations ranged from 61 micrograms/m3 in foundries to 5,578 micrograms/m3 in ricemills, with five industries (adhesives, metalworking, ricemilling, sawmilling, and shoemaking) exceeding the US EPA 24-hr ambient air standard for PM-10. Formaldehyde concentrations exceeded the threshold limit value (TLV) in adhesives factories. Other vapours and elements measured were well below TLVs.

Aerosols↗
PubMed2001

[Medical certificate in psychiatry: practical aspects].

Among certificates written in psychiatry, some are obligatory, admission certificate, in case of automatically hospitalization or that asked by a third party, certificate of 48 hours: in which the psychiatrist of the admission' service describes the state of the patient and indicates the necessity or not to continue the hospitalization, monthly certificate: to justify the maintenance of hospitalization or to ask its end and certificate of situation be written in some particular circumstances. Others concern the cases of expert appraisement (in civilian or penal rights) or in the framework of medical controls asked by the employer. Other certificates are optional or customary. They could be delivered if asked by the patient. These considerations incite to follow scrupulously ethical rules and common sense when doing these certificates. Finally, The certificate has always to be given to the patient personally. That will be mentioned down of the document.

Commitment of Persons with Psychiatric Disorders↗
PubMed2000

Ceftazidime-resistant Klebsiella pneumoniae bloodstream infection in children with febrile neutropenia.

OBJECTIVES: To evaluate prevalence of ceftazidime-resistant Klebsiella pneumoniae (CRKP) in the pediatric oncology unit of University Hospital, Kuala, Lumpur, and to identify differences between febrile neutropenic pediatric patients with CRKP and ceftazidime-sensitive K. pneumoniae (CSKP) bacteremia. MATERIALS AND METHODS: Febrile neutropenic patients treated between January 1996 and December 1997 at the pediatric oncology unit of University Hospital, Kuala Lumpur, were prospectively studied. Empirical antibiotic therapy consisted of ceftazidime and amikacin. Those who developed K. pneumoniae bacteremia were identified, and clinical features analyzed. Ceftazidime-resistance was documented via disk-diffusion testing. Production of extended-spectrum beta-lactamase (ESBL) was inferred on the basis of synergy between ceftazidime and amoxicillin-clavulanic acid. The different features between the two groups and variables associated with the development of CRKP bacteremia were analyzed using chi-square and t-tests and calculation of odds ratios. A multivariate analysis was used to identify independent factors for CRKP development. RESULTS: Ceftazidime-resistance was seen in 51.6% of all K. pneumoniae isolates, and all these isolates were inferred to be ESBL producers. All isolates were sensitive to imipenem. Susceptibility to gentamicin was 90.5%. The mean continuous hospital stay prior to the detection of bacteremia was 13.7 days overall, but significantly longer in the CRKP group (21.9 d) compared to the CSKP group (4.3 d) (P = 0.003). Children with CRKP were more likely to have received antibiotics in the 2 weeks prior to detection of bacteremia (87.5% of cases) than the CSKP group (20.0% of cases) (P = 0.0008). Sepsis-related mortality was higher in those with CRKP (50.0%) than in the CSKP group (13.3%) (P = 0.02). Patients who did not receive CRKP-directed antibiotics within 48 hours of admission were more likely to have a fatal outcome than those who did (P = 0.009). Logistic regression analysis identified use of third-generation cephalosporins 2 weeks prior to presentation and a hospital stay of 2 weeks or more as independent risk factors for development of CRKP. CONCLUSIONS: More than half of total K. pneumoniae isolated from blood cultures in the unit were ceftazidime-resistant. Children with febrile neutropenia with prolonged hospital stay and recent prior antibiotic exposure are at high risk of developing CRKP bacteremia. Mortality was significantly higher in this group. Early commencement of appropriate antibiotics (e.g., imipenem with or without gentamicin), according to susceptibility study results, may be beneficial in such circumstances.

Anti-Bacterial Agents↗
PubMed2000

Severe allergic contact dermatitis induced by paraphenylenediamine in paint-on temporary 'tattoos'.

Paraphenylenediamine (PPD) is a black dye with well known sensitizing properties. Its increasing use as a skin paint to produce temporary 'tattoos' has led to recent reports of allergic contact dermatitis. Hitherto, such cases of allergic contact dermatitis due to PPD have been localized to the original site of application of the skin paint. We report two cases of severe allergic reactions to paint-on 'tattoos'. Both of these patients had no prior history of sensitivity to PPD, although case 2 had previously used permanent hair dyes. In both cases, the primary eruption at the 'tattoo' site was followed within days by a generalized eruption which ultimately required treatment with oral corticosteroids, because the initially prescribed topical corticosteroids proved ineffective.

Adult↗
PubMed2000

Technetium 99mTc-DTPA clearance in the evaluation of pulmonary involvement in patients with diabetes mellitus.

Systemic thickening of capillary endothelial basement membrane underlies the chronic complications of human diabetic microangiopathy. Since 99mTc-DTPA aerosol scintigraphy is a sensitive, non-invasive test of membrane permeability, we decided to study the effect of diabetes on the permeability of lung epithelium in diabetic patients using this test. Fifty (NIDDM) patients, aged 40-70 years, with or without complications, and who were non-smokers, were subjected to evaluation using 99mTc-DTPA aerosol. At the same time, pulmonary function tests, including carbon monoxide diffusion capacity, were done. Normal non-smoking subjects with no history of cardio-respiratory disease, who underwent 99mTc-DTPA and pulmonary function tests, served as controls. The risk factors which included age, sex, degree of control and presence of complications were noted. Twenty-nine (58%) of the patients had abnormal 99mTc-DTPA clearance. Thirty-four percent of the patients with complications and 24% of those without complications had abnormal clearance. Complications recorded included retinopathy, neuropathy and nephropathy. Fifty-five percent of patients with abnormal 99mTc-DTPA had suffered from diabetes for longer than 10 years. Sixty-two percent of patients with poor glycaemic control had abnormal 99mTc-DTPA. Diffusion capacity was not significantly affected in patients with complicated diabetes. Our preliminary results suggest that 99mTc-DTPA is a potentially sensitive test in assessing the degree of lung affection in diabetic patients. No significant correlation exists between diffusion capacity and 99mTc-DTPA. The risk factors did not affect the 99mTc-DTPA clearance, probably due to the small sample size.

Adult↗
PubMed2000

Assessment of non-heart-beating donor (NHBD) kidneys for viability on machine perfusion.

UNLABELLED: The shortage of organs has resulted in renewed interest in organs from non-heart-beating donors (NHBD). Viability assessment of such organs may reduce the incidence of delayed graft function and primary non-function. In Phase III of the NHBD programme, introduction of machine perfusion enabled the assessment of these marginal donors. Since then the graft survival has been 88.4% compared with the previous phase where machine perfusion or viability assessment was not done (45.5%). The parameters used were total glutathione S-transferase (GST) in the perfusate, the intrarenal vascular resistance (IRVR) and flow characteristics over time. METHODS: All NHBD kidneys were machine perfused through a locally developed perfusion system. The viability was assessed by serial measurements of the above-mentioned parameters. RESULTS: Forty-two local NHBD kidneys were retrieved and one kidney was imported, of which 19 donors (i.e. 38 kidneys) were of the uncontrolled (category II) donors. After viability assessment on machine perfusion; two kidneys were discarded due to positive tests for syphilis, four kidneys had high total GST levels, five kidneys due to high IRVR and poor flow characteristics and one did not flush on retrieval. Three kidneys were exported after viability tests. In 28 NHBD kidney recipients, immediate graft function was seen in two kidneys, 22 (84.6%) developed delayed graft function. One kidney had primary non-function, and two recipients lost their grafts, due to chronic rejection and renal vein thrombosis. There were two deaths, unrelated to transplantation. Graft survival was achieved in 88.4% (23/26 graft survival in phase III) of cases. CONCLUSION: Machine perfusion and assessment of NHBD kidneys has been successfully introduced to the Newcastle NHBD programme. This approach, using renal transplants from largely category II donors produced a success rate of 88.4% which was significantly better than the phase II period (45.5%) of the program (p=0.023, Fisher 2 tail test).

Humans↗
PubMed2000

Anisakis and fish induced urticaria.

Skin tests using prepared Anisakis antigen and commercially available fish antigen were done. Also, specific IgE detection for Anisakis was done by RAST method. Two patients out of 20 showed positive skin test and positive RAST to larval Anisakis antigen, and negative skin test to fish antigen. These 2 patients were considered hypersensitive to Anisakis.

Animals↗
PubMed1999

Familial hydroa vacciniforme.

Hydroa vacciniforme is a rare, idiopathic photodermatosis with an onset in childhood and characterized by acute vesiculation, crusting and scarring following sun exposure. Familial cases are extremely rare with only one previous report. We report a brother and sister, both of whom have developed hydroa vacciniforme.

Child↗
PubMed1999

Allergic contact dermatitis to plastic banknotes.

Allergic contact dermatitis to ultraviolet (UV) cured acrylates occurs predominantly in occupationally exposed workers. Two men presented with dermatitis coinciding with the location of banknotes in their pockets. Patch testing confirmed allergic contact dermatitis to multiple acrylates and Australian plastic banknotes. This is the first report of contact allergy to acrylates present in Australian plastic banknotes.

Acrylates↗
PubMed1998

Accumulation of heavy metals in freshwater molluscs.

Heavy metals in the aquatic environment have to date come mainly from naturally occurring geochemical materials. However, this has been enhanced by human activity such as gold mining in the case of heavy metal pollution in Sg Sarawak Kanan. The high suspended solid loads in the river have quite efficiently removed most soluble metals from the water and trapped them in the bottom sediment. Three freshwater mollusc species were collected at the point source of the heavy metal pollutants and analysed for the heavy metal contents in their tissues and shells. Two of the mollusc species (Brotia costula and Melanoides tuberculata) are purely freshwater species while the Clithon sp. nr retropictus is able to survive in fresh and brackish water environments. The Brotia costula and the Clithon sp. are the edible species which are sold in the market. Accumulation of As, Cu, Fe, Se and Zn in all the three mollusc species were determined and the level of As in the tissues of Brotia costula and the Clithon sp. was much higher than the permissible level for human consumption. The mollusc species also demonstrated different preferences for the uptake of different metals. Variations in the heavy metal contents in the shell and tissues of the same species were also observed.

Animals↗
PubMed1995

Infected arteriovenous hemodialysis graft presenting as left and right infective endocarditis.

Prosthetic grafts have become an acceptable alternative to the autogenous arteriovenous dialysis fistula. The major drawback in their use for the dialysis patient is infection. We present a case of infected polytetrafluoroethylene arteriovenous fistula (endarteritis) with signs of unilateral splinter hemorrhage, Janeway lesions in the affected limb and septic venous embolization to the lungs. The graft eventually ruptured requiring emergency surgery. Staphylococcus aureus is by far the most common implicated organism. An otherwise non-threatening infection at a fistula site can lead to more serious complications such as infective endocarditis.

Blood Vessel Prosthesis↗
PubMed1995

Comparison of the life table characteristics of Anopheles sergentii (Diptera: Culicidae) from two malarious areas in Egypt.

Life table characteristics were examined for the malaria vector, An. serenti from two Faiyum villages: Tersa (T) and El Nazlah (N) from Siwa oasis (Sw) under constant laboratory conditions at 25 degrees C and 70% RH. Females of T, N and Sw completed 4, 5, and 2 gonotrophic cycles (gc) respectively. The first gc required a significantly longer period (p<0.05) than the subsequent ones. Development times for Sw immatures were longer (p<0.05) than for the other colonies. Life expectancies at emergence for males of the 3 colonies were significantly shorter than for their respective females. Generation time was shorter (p<0.05) for T (mean = 31.15 days) than for Sw (37.81 days) or N (43.64 days) colonies. The birth rate of Sw colony (mean = 0.33 female female/female) was significantly higher (p<O.05) than those of the other colonies. The other biological parameters: fecundity, egg hatch times and rates, survivorship from egg eclosion to adult emergence, male and survivorships, net reproductive rate, intrinsic rate of increase all showed no colony variations. The study concluded that variation among colonies in certain biological aspects may not reflect strain differences.

Age Factors↗