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Biomedical subjects

M Dawood

Publications and source records attributed to M Dawood.

At least 19 recordsLinked to original sources
PubMed2006

Survival analysis of liver transplant patients in Canada 1997-2002.

UNLABELLED: Liver transplantation is an important health care issue for Canadians. Very few studies have assessed survival and determinants of survival in liver transplant patients in Canada. METHODS: We carried out an epidemiological analysis of 1 year survival and determinants of 1 year survival in liver transplant patients, using Canadian Organ Replacement Registry data (1997-2002). Survival curves were plotted by the Kaplan-Meier method. Cox proportional hazards analysis was applied to evaluate hazard ratios with different age groups, gender, ethnicity, blood groups, donor type, pretransplantation medical status, and HBV infection status. RESULTS: A total of 1164 liver transplant patients were included in the analysis. One-year survival rate was 84.7%. Male recipients had a 21% higher risk of developing organ failure than females. Recipients over 60 years of age had a 5% lower survival probability in comparison with recipients below 20 years of age. Pacific Islanders and Aboriginals had 32% and 9% lower survival probabilities, respectively, in comparison with Caucasians. Type B blood recipients had a 12% higher survival probability, whereas type AB blood recipients had a 7% lower survival probability compared with type O blood recipients. Twenty-six live organ recipients had 40% higher survival probabilities than 1138 cadaveric organ recipients. Patients with fulminant hepatitis (status 3F) had the highest survival, while patients with fulminant failure in ICU with intubation/ventilation (status 4F) had the lowest survival. One hundred sixty-seven recipients with positive HBsAg antigen showed 10% lower survival probability than 997 cases with negative HBsAg antigen. CONCLUSION: In Canada, the first year survival rate is about 85%, which is comparable with other industrialized countries. Type of donor organs and recipient gender, ethnicity, ABO blood group, pretransplantation medical status, and HBV infection status had significant affects on the recipient survival.

Canada↗
PubMed2005

Epidemiological study of hepatitis B virus infection in Manitoba, Canada, 1992-2003.

In comparison with other Canadian provinces and most Western countries, the province of Manitoba maintains a different vaccination policy for hepatitis B. This policy provides selective antenatal screening for hepatitis B in women and an inoculation program for hepatitis B vaccination for fourth-grade pupils. There has been increasing concern for this policy with regard to its influence on secular trends of acute hepatitis B incidence in Manitoba. This created a need to summarise the epidemiological characteristics of hepatitis B virus (HBV) infection in Manitoba and to allocate finances and human resources for future prevention programs. The Cadham Provincial Laboratory in Winnipeg, a Canadian Public Health Laboratory, is responsible for testing all specimens for diagnosis of various common infectious diseases in Manitoba. During the period from 1 January 1992 to 31 December 2003, a total of 285,946 clinical specimens were submitted to this laboratory, which confirmed 310 cases of acute HBV and 7,556 cases of chronic HBV infection. A total of 18,168 individuals were identified as having vaccine-induced immune status. The incidence rate of acute HBV infection has significantly decreased from 6.52/100,000 person-years in 1996 to 0.86/100,000 person-years in 2003. Annual prevalence rates of chronic HBV infection in Manitoba increased slightly from 42.96 cases/100,000 population in 1992 to 71.47 cases/100,000 population in 2003. Incidence rates were generally higher in men than in women at all age groups, with values of 2.65 and 1.65 per 100,000 population, respectively (chi-square=15.768, p value <0.001). The highest incidence rate for both males and females was observed in the age group 30-34 years. The North Eastman and Winnipeg Regional Health Authorities showed significantly higher incidence rates of acute hepatitis B compared with the other nine Regional Health Authorities. Selective hepatitis B vaccination programs for children in Manitoba had achieved the greatest success in the prevention of vertical and horizontal transmission. There is an urgent need to develop cost-effective harm-reduction strategies for hepatitis B prevention among adults (aged 30-34) and groups at risk in Manitoba.

Adolescent↗
PubMed2005

Screening for Type 2 diabetes in the accident and emergency department.

AIM: To assess the proportion of patients, aged 40 years and over, attending an inner city accident and emergency department that have Type 2 diabetes, and the proportion previously undiagnosed, and to assess whether the identification of undiagnosed Type 2 diabetes is feasible in this setting. METHODS: Five hundred unselected people participated. All completed a demographic questionnaire regarding risk factors for diabetes. In those without known diabetes, random capillary blood glucose (CBG) was measured. If this was greater than 7.0 mmol/l, patients were asked to return for two fasting blood glucose tests. Diagnosis of diabetes was based on World Health Organization criteria. RESULTS: Of the 500 participating subjects, 73 were already known to have Type 2 diabetes. Of the remaining 427 subjects, 36 had CBG>7.0 mmol/l. All 36 returned for fasting blood tests: 13 fulfilled the diagnostic criteria for Type 2 diabetes, eight for impaired fasting glucose (IFG), and 15 had normal fasting glucose values. The prevalence of Type 2 diabetes was therefore 17.2%, including 2.6% with a new diagnosis, and 14.6% with pre-existing disease; 1.6% were found to have IFG. Body mass index was greater in those with Type 2 diabetes (previously and newly diagnosed) [27.1 (5.15) (mean+/-standard deviation)] vs. 25.8 (4.70) kg/m2; unpaired t-test P=0.0213), and those with Type 2 diabetes were more likely to be of black and minority ethnic origin (57 vs. 28%; chi2 P<0.001) and to have a first-degree family history of diabetes (45 vs. 23%; chi2 P<0.001). CONCLUSIONS: It can be estimated from this survey that, annually, this case-finding methodology could identify 539 (95% CI 249-828) people aged 40 years and over attending our accident and emergency department with previously undiagnosed Type 2 diabetes.

Adult↗
PubMed2005

Motion correction in PET/CT.

Motion in PET/CT leads to artifacts in the reconstructed PET images due to the different acquisition times of positron emission tomography and computed tomography. The effect of motion on cardiac PET/CT images is evaluated in this study and a novel approach for motion correction based on optical flow methods is outlined. The Lukas-Kanade optical flow algorithm is used to calculate the motion vector field on both simulated phantom data as well as measured human PET data. The motion of the myocardium is corrected by non-linear registration techniques and results are compared to uncorrected images.

Heart↗
PubMed2003

Reduced isolation-induced aggressiveness in mice following NAALADase inhibition.

RATIONALE: Long-term individual housing increases aggressive behavior in mice, a condition termed isolation-induced aggression; this aggressiveness is reduced by some antidepressants and anxiolytics. NMDA antagonists also inhibit isolation-induced aggression in mice. The enzyme N-acetylated-alpha-linked acidic dipeptidase (NAALADase) hydrolyzes the neurotransmitter N-acetylaspartylglutamate (NAAG) to form glutamate and N-acetylaspartate; NAAG acts as a partial NMDA agonist as well as a full agonist at the presynaptic metabotropic glutamate receptor 3 (mGluR3), where it acts to reduce glutamate release. OBJECTIVE: We postulated that NAALADase inhibition would reduce isolation-induced aggression in mice. METHODS: We tested whether acute exposure to the NAALADase inhibitor 2-[[hydroxy[2,3,4,5,6-pentafluorophenyl)methyl]phosphinyl]methyl] pentanedioic acid (GPI-5232), administered 30 min prior to a social interaction test, would inhibit aggressive behavior in SJL mice that had been individually housed long term. RESULTS: Administration of GPI-5232 (30 mg/kg, IP) inhibited initiation of aggressive behavior, indicated by greater latencies to display tail-rattling, attack and biting, and by fewer mice initiating aggressive behavior, compared to mice that received vehicle. In addition, GPI-5232 treated mice had fewer tail-rattling responses to a non-aggressive conspecific. CONCLUSIONS: The effectiveness of GPI-5232 in this animal model suggests that NAALADase inhibition may be a novel therapeutic approach to reduce or inhibit heightened aggressiveness, and possibly to treat aggressive behavior associated with psychiatric disorders.

Aggression↗
PubMed2001

A pilot study of the technical quality of telemedical consultations for remote trauma management.

The technical performance of a telemedical system when used for remote trauma management was compared with face-to-face consultation. Two rooms, 20 yards apart, were linked telemedically in the same Accident & Emergency Department. Two hundred patients, with 'minor' and 'moderate' injuries, underwent the two types of consultation. The Accident & Emergency consultant marked physical parameters using a five-point pre-determined Likert scale. The following parameters were thought to be of excellent quality when compared to face-to-face consultation: overhead fluorescent lighting for the background illumination, video lighting for a close-up view, sound quality after volume adjustment, echo-cancellation after adjustment and lip synchronization. However, the following parameters scored poorly: sound before volume adjustment, echo-cancellation before adjustment, fine and coarse movements. It can be concluded that the quality of lighting and image quality are good in telemedicine. Sound and movement still present some problems. This technology is likely to be used more frequently for remote trauma management.

Humans↗
PubMed2001

Changes in the workplace with telemedicine.

The opinions of 110 emergency nurse practitioners (ENPs) practising telemedicine in 11 British minor injury units were sought using a questionnaire. There were 90 respondents (82%). The respondents thought that, since telemedicine had been introduced, they had become more open to change (96%) and more ready to grasp opportunities (93%). They considered that they were more keen to learn new things (99%) and were better disposed to teaching others (90%). They adopted a more advisory and supportive role (80%), found the work environment more varied (83%) and were well disposed to teamwork (64%). The power balance with doctors had changed (86%) and doctors indulged in dialogue rather than direction (69%). The results suggest that although changes have started in the workplace, they have not been as dramatic as a previous study of patients had predicted.

Attitude of Health Personnel↗
PubMed1999

Delayed referral of black, Hispanic, and older patients with chronic renal failure.

Delayed referral (defined as a serum creatinine concentration > 4 mg/dL at referral) of patients with chronic renal failure to the nephrologist is common in the United States. We retrospectively examined the records of 220 consecutive patients referred to an urban teaching hospital nephrology division for evaluation of chronic renal failure from January 1987 to December 1994 to detect any relationship between race, renal diagnosis, or age and the timing of referral of medically-insured patients with chronic renal failure. We documented serum creatinine concentration and hematocrit at referral, length of time under the care of a nephrologist (interval from referral to initiation of dialysis), and total number of clinic visits. The 220 study subjects (120 women, 100 men) included 139 blacks (63%), 61 whites (28%), 16 Hispanics (7%), and 4 Asians (2%) aged 51.7 +/- 1.06 years (mean +/- standard error of the mean) at referral. At referral, nonwhites (black and Hispanic patients) had a greater mean serum creatinine concentration than whites (4.3 +/- 0.38 v 3 +/- 0.24 mg/dL; P = 0.001), as well as a lower mean hematocrit (31.7% +/- 1.3% v 34.7% +/- 0.9%; P = 0.001). Mean length of time under the care of a nephrologist was shorter in nonwhites (13 +/- 0.8 months) than whites (43.5 +/- 4.8 months; P = 0.001). Delayed referral was almost six times more likely in nonwhites than whites (odds ratio, 5.6; 95% confidence interval [CI], 1.52 to 20; P = 0.008) and five times more likely in those aged older than 55 years than in those 55 years or younger (odds ratio, 4. 7; 95% CI, 1.37 to 16; P = 0.01). The greater the serum creatinine concentration at referral, the greater the odds of receiving less than 12 months of nephrologic care before initiation of dialysis (odds ratio, 1.8; 95% CI, 1.04 to 3.13; P = 0.03). We conclude that even among those patients with health insurance, delayed referral to the nephrologist is more likely in black, Hispanic, and older patients with chronic renal failure than in their white or younger counterparts.

Black or African American↗
PubMed1999

Seroprevalence of Helicobacter pylori, incidence of gastric cancer, and peptic ulcer-associated hospitalizations in a Canadian Indian population.

The living conditions of many aboriginal communities in Canada may place their residents at risk for H. pylori infection. Our aims were to determine: (1) the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance of H. pylori infection in this population, and (3) if H. pylori could be identified by polymerase chain reaction from the local water. A demographic questionnaire was administered, and blood was collected from subjects in an Indian community in northwestern Manitoba. The serum was analyzed by ELISA for IgG to H. pylori and to CagA. ABO and Lewis antigens were tested. Age-adjusted incidence of gastric cancer and of hospitalizations associated with diagnoses of peptic ulcer were determined for the Indian and non-Indian Manitoba population in the years 1989-1993. Nested PCR was performed on lake water using H. pylori-specific primers and the amplicons probed with an internal Dig-labeled probe. Three hundred six (59%) of approximately 518 individuals who were resident in the community at the time of the study were enrolled. The ELISA for H. pylori was positive in 291 (95%). There was no association between H. pylori seropositivity and age, sex, gastrointestinal complaints, medications, housing characteristics, and ABO or Lewis antigen status. CagA was positive in 84.5% of infected subjects. The average annual age-adjusted incidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higher for treaty-status Indians (394.3/100,000) than for non-Indians (203.8/100,000), but gastric cancer rates were similar (11.2/100,000 vs 11.6/100,000). No H. pylori DNA was detected in the lake water. In conclusion, the seroprevalence of CagA-positive H. pylori is high in this representative Manitoban Indian community. This may be associated with an increased risk for peptic ulcer disease but is not associated with an increased risk for gastric cancer.

Adolescent↗
PubMed1999

Helicobacter pylori in the Canadian arctic: seroprevalence and detection in community water samples.

OBJECTIVE: Many North American arctic communities are characterized by risk markers associated with Helicobacter pylori (H. pylori) infection, including overcrowded housing and inadequate water supply and sanitation systems. Our aim was to determine the seroprevalence of H. pylori infection in two traditional Inuit communities in the central Canadian arctic and to test for the presence of H. pylori, by polymerase chain reaction (PCR), in local water supplies. METHODS: Samples of venous whole blood from adults and capillary blood from children were collected and analyzed by enzyme immunoassay and Helisal Rapid Test, respectively, for IgG antibody to H. pylori. Antibodies to CagA were detected by enzyme immunoassay, and ABO and Lewis antigens were also determined. Demographic and clinical information were collected by questionnaire. Water samples from each community were tested for H. pylori by PCR. RESULTS: One hundred-thirty (50.8%) of 256 subjects from the two communities were positive for H. pylori IgG antibodies. Seropositive subjects were more likely to be male, compared with seronegative individuals (p = 0.01). Antibody status did not differ with respect to age, community, alcohol or cigarette use, number of persons per household, gastrointestinal complaints or previous investigations, medications, or presence of blood group O, Lewis a-b+. CagA antibodies were detected in 78 (61.9%) of 126 H. pylori-seropositive subjects tested; however, 41 (35.3%) of 116 H. pylori-seronegative subjects were also CagA positive. Water samples taken from the water delivery truck in Chesterfield Inlet and two lakes near Repulse Bay were positive for H. pylori. CONCLUSION: The seroprevalence of H. pylori in the study group was higher than rates in southern Canadian populations, but lower than the seroprevalence previously documented in a Canadian subarctic Indian (First Nations) community. The detection of H. pylori in local water supplies may indicate a natural reservoir for the organism or possible contamination from human sewage.

ABO Blood-Group System↗
PubMed1998

Timing of initiation of uremia therapy and survival in patients with progressive renal disease.

We conducted a prospective cohort study to detect any relationships between specific clinical features and laboratory indices at initiation of hemodialysis and long-term survival. One hundred and thirty-nine consecutive patients with chronic renal failure hospitalized to start maintenance hemodialysis between January 1990 and December 1994 were enrolled, and follow-up was completed through December 1995. At baseline, subjects were assigned to one of five groups based on their major indication for initiation of hemodialysis. The indications were: (a) nausea and vomiting; (b) severe weakness; (c) no major symptom (dialysis started because of 'high' serum creatinine and blood urea nitrogen concentrations); (d) volume overload, and (e) miscellaneous (angina, pericarditis, seizure, pruritus, and hyperkalemia). Blood urea nitrogen, serum creatinine and serum albumin concentrations were measured once before the first dialysis. The main outcome measure was death. The 139 study subjects included 77 women and 62 men comprising 116 Blacks (83%), 15 Hispanics (11%), and 8 Whites (6%) of mean age 54 +/- 15 years. Mean length of follow-up was 39 months. At baseline, mean blood urea nitrogen concentration was 121 +/- 38 mg/dl, mean serum creatinine concentration was 12.6 +/- 5.2 mg/dl, and mean serum albumin concentration was 3.5 +/- 0.62 g/dl. Forty-two subjects (30%) died during follow-up. Cox regression analysis showed that there was no significant association between mortality and any of the indicators evaluated (indication for initiation of dialysis (p = 0.2), serum creatinine concentration (< 10 vs. > or = 10 mg/dl) (p = 0.8), blood ure nitrogen concentration (< 100 vs. > or = 100 mg/dl) (p = 0.68) and serum albumin concentration (< 4 vs. > or = 4 g/dl) (p = 0.62). All analyses included adjustment for age and diabetes. We conclude that in patients with chronic renal failure, the clinical features and laboratory indices used as guidelines for initiation of renal replacement therapy do not correlate with survival. Objective parameters that will permit initiation of dialysis at a time that will maximize survival in patients with chronic renal failure are needed.

Female↗