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Biomedical subjects

F M White

Publications and source records attributed to F M White.

At least 19 recordsLinked to original sources
PubMed1995

Attomole biomolecule mass analysis by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance.

Significantly improved sensitivity for analysis of biomolecules by MALDI FT-ICR mass spectrometry is achieved by (i) microscope-monitored sample deposition onto a small indentation on the probe tip and (ii) multiple remeasurement of ions from a single laser shot. A simple modification to the solids probe tip allows for microdeposition of a few amols of analyte onto small indentation spots previously aligned with the laser beam. Ion multiple remeasurement of the same ion packet enhances the signal-to-noise ratio and thus extends the achievable FT-ICR MS detection limit. We demonstrate that FT-ICR can be used to detect parent and structurally significant fragment ions of peptides and phospholipids at low amol amounts. Positive ion mass spectra for approximately 90 amol of a mixture of angiotensin II and bradykinin, approximately 40 amol of dipalmitoylglycerophosphatidylcholine, and approximately 8 amol of substance P constitute the lowest reported detection limits to date for FT-ICR mass analysis of MALDI-generated ions.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1995

Structural characterization of phospholipids by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry.

Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry provides for structural analysis of the principal biological phospholipids: glycerophosphatidylcholine, -ethanolamine, -serine, and -inositol. Both positive and negative molecular or quasimolecular ions are generated in high abundance. Isolated molecular ions may be collisionally activated in the source side of a dual trap mass analyzer, yielding fragments serving to identify the polar head group (positive ion mode) and fatty acid side chains (negative ion mode). Azimuthal quadrupolar excitation following collisionally activated dissociation refocuses productions close to the solenoid axis; subsequent transfer of product ions to the analyzer ion trap allows for high-resolution mass analysis. Cyro-cooling of the sample probe with liquid nitrogen greatly reduces matrix adduction encountered in the negative ion mode.

Anions↗
PubMed1994

The control of tuberculosis in the Caribbean.

A survey of the Ministries of Health in the English-speaking Caribbean countries was conducted with the purpose of collecting information about current capacity in the prevention and control of tuberculosis. A response rate of 78.9% was achieved. The results of this survey indicate that tuberculosis control programmes in the English-speaking Caribbean are limited, and inadequately address issues relating to multi-drug resistant disease and co-infection with human immunodeficiency virus (HIV). Limitations and implications of this survey are discussed.

Caribbean Region↗
PubMed1994

Modeling the HIV/AIDS epidemic in the English-speaking Caribbean.

The study reported here examines the past and potential future impact of HIV/AIDS in 19 nations of the primarily English-speaking Caribbean. The authors use DemProj, a demographic projection model, to explore two different HIV scenarios. In the low scenario adult HIV prevalence stabilizes at 2% in the year 2000, and in the high scenario adult HIV prevalence stabilizes at 5%. By the year 2010, annual AIDS incidence exceeds 11,000 cases in the low scenario and 28,000 in the high scenario. In both scenarios, 70% of the cases are in young adults 20-45 years old and 12% are in children 0-15. Age-specific mortality is more than doubled in the 20-40 age range in the low scenario, and more than quadrupled in the high scenario. The impact on death rates is also severe among children 0-10. In assessing the economic impact, the authors estimate that the total annual costs of the epidemic will approach US$ 500 million (in constant 1989 US$) or 2% of GDP in the low scenario, and will exceed US$ 1,200 million or 5% of GDP in the high scenario.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Cholera in metropolitan Manila: foodborne transmission via street vendors.

Reported are the results of an unmatched case-control study to determine the risk factors associated with acquisition of cholera in Manila. Cases were patients admitted to the San Lazaro Hospital between July and September 1989 and whose stools yielded Vibrio cholerae O1 on culture. Controls were patients admitted to the same hospital and who had no history of diarrhoea or of having taken antibiotics during the 3 days prior to admission. Of the 158 cases and 158 controls who had bought food from street vendors, cases were more likely to have bought the following items: pansit (rice noodles with shrimp, meat, and vegetables), mussel soup, spaghetti, fish balls, pig blood coagulated with vinegar, and salty brine shrimp with vegetables. Cases were also more likely to lack piped water at home. An unconditional logistic regression analysis indicated that only pansit (OR = 2.15, 95% CI = 1.32-3.51), mussel soup (OR = 2.29, 95% CI = 1.06-4.95), and the absence of piped water at home (OR = 2.70, 95% CI = 1.63-4.46) remained as risk factors. As control measures we recommend stricter implementation of the food sanitation code and the licensing of street food vendors.

Adolescent↗
PubMed1993

Attitudes and practices of pesticide users in Saint Lucia, West Indies.

This article reports the results of a Saint Lucia survey, part of a larger program, that was the first to document the prevalence of suboptimal safety practices among vector control and farm workers using pesticides in the English-speaking Caribbean. Among other things, the survey found that many of 130 pesticide users surveyed were unaware that the skin and eyes were important potential routes of absorption. Over a quarter said they had felt ill at some point as a result of pesticide use. About half the respondents said they had received more than "introductory" training in safe pesticide use, and most said they always found labels or directions affixed to pesticide containers. However, about half said they never or only sometimes understood the labels, and many of those who said they understood did not always follow the instructions. About a quarter of the smokers said they smoked while using pesticides; about a sixth of the survey subjects said they ate food while using pesticides; and over 60% said they never wore protective clothing.

Adolescent↗
PubMed1992

Surveillance in evacuation camps after the eruption of Mt. Pinatubo, Philippines.

To obtain accurate, timely data on the health status of persons in evacuation camps after the eruption of the Mt. Pinatubo volcano, the Philippine Department of Health (DOH) conducted a survey of the health needs of the evacuees and established disease surveillance in each camp. Surveys of the camps revealed that sources of potable water, sanitary means of waste disposal, and shelters were inadequate. Disease surveillance showed that measles, acute respiratory infections, and diarrhea were the most important problems. Surveillance detected outbreaks of measles and an outbreak of vomiting and diarrhea in the camps. Deaths, primarily caused by measles (31%), diarrhea (29%), and respiratory infections (22%), totaled 349 in the first 12 weeks. Death rates peaked in the seventh week, when a death rate of 26/10,000 occurred among the Aetas, a tribe evacuated from the slopes of the volcano. The surveys guided the DOH in allocating supplies and medicine, while disease surveillance enabled disaster managers to monitor the effectiveness of health programs, identify high-risk groups, and respond appropriately to the situation.

Diarrhea↗
PubMed1992

Epidemiological indicators and the epidemiology of measles in the English-speaking Caribbean and Suriname.

The main purpose of this article is to discuss the definitions and limitations of the indicators used to study the epidemiology of measles in the English-speaking Caribbean and Suriname. In addition, the epidemiology of measles over the past ten years is briefly reviewed, with a focus on recent epidemics. The predicted epidemiological picture of measles over the next few years is also discussed and, finally, the difference between elimination and eradication of measles is explained.

Adolescent↗
PubMed1989

The epidemiology of mumps in southern Alberta 1980-1982.

The full spectrum of mumps in Southern Alberta was studied over the years 1980-1982. In the community, a random sample of 3,497 children was tested for prevalence of immunity to mumps. The 1,816 who were not immune were retested after one year. The incidence of new immunity was 16.5%. Most seroconverters had no illness suggestive of mumps. History of previous mumps or immunization were found to be unreliable predictors of serologic immune status. In the family study, information was obtained on 342 cases diagnosed as mumps by family physician recorders. The overall complication rate was 10.8% and the secondary attack rate within families was 11.7%. Hospital records of all 25 patients admitted in Calgary with mumps during the same period were analyzed. Estimated costs of unopposed mumps over 20 years compared with the estimated costs of vaccination showed that a vaccination program could give a benefit-cost ratio between 6.4 and 247. These studies show that mumps is a mild disease with relatively few serious complications or sequelae. Even so, there would be definite medical and economic benefit with immunization. A low-cost addition of mumps vaccine to the immunization program would be justified.

Adolescent↗
PubMed1988

Chemicals, birth defects and stillbirths in New Brunswick: associations with agricultural activity.

We describe a series of investigations that were conducted in support of the Task Force on Chemicals in the Environment and Human Reproductive Problems in New Brunswick. Geographic and temporal analyses and case-control studies, with the use of vital statistics, hospital records, the Canadian Congenital Anomalies Surveillance System and chemical databases, revealed no association between pesticides used in forestry and reproductive problems. Evidence of an association between the potential exposure to agricultural chemicals and three major anomalies combined as well as spina bifida without hydrocephalus was found. More plausible was an association between stillbirths and such exposure during the second trimester of pregnancy. This finding, along with the cyclic patterns of stillbirth in the agricultural Saint John River basin and the somewhat higher stillbirth rates in New Brunswick than in adjacent provinces or in Canada as a whole, suggests that further attention should focus on possible associations between agricultural activity and stillbirths.

Abnormalities, Drug-Induced↗
PubMed1986

Associations of body mass index and waist:hip ratio with hypertension.

Canada Fitness Survey data for people aged 20 to 69 years were analysed by means of linear discriminant analysis to determine the effect of age, weight relative to height (body mass index) and weight distribution (waist:hip ratio) on hypertension (defined as diastolic blood pressure of 90 mm Hg or more) for both sexes separately. All three variables had independent effects on hypertension, but partial correlation coefficients indicated that the contribution of waist:hip ratio was secondary to that of body mass index. The association of measurements of body fat (five skinfold measurements) with hypertension was also examined; overall these measurements gave no advantage over the more simply measured body mass index. The results confirm the importance of assessing the predominant location of body fat and the body mass index when examining excess weight in relation to disease.

Adipose Tissue↗
PubMed1986

Rate of slaughter may increase risk of human brucellosis in a meat-packing plant.

Researchers conducted an epidemiologic investigation of an outbreak of brucellosis at a meat-packing plant, where work was interrupted by a strike. The investigation revealed that the risk of infection with brucellosis may coincide with the rate at which reactor cattle are slaughtered, a factor often overlooked in other reports which investigated outbreaks of brucellosis. The slaughter of 20 to 25 reactor cattle per day was the estimate of the critical number of reactor cattle when the risk of infection is most likely to occur. Of the 193 workers studied, 17 (8.8%) were seropositive, but only eight (4.1%) were presumptive cases. Young, newly employed workers who did not wear glasses were at greatest risk of infection.

Abattoirs↗