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Biomedical subjects

N White

Publications and source records attributed to N White.

At least 19 recordsLinked to original sources
PubMed1992

Medical complications of substance abuse.

Substance abuse is involved in many instances of intentional and unintentional injury. It can also cause medical complications that affect various organ systems--among them, the cardiac, vascular, neurologic, pulmonary, gastrointestinal, immunologic, and reproductive systems. Even though there is pressure to create a new medical specialty to specifically address substance-abuse issues, the truth is that any physician, regardless of specialty, may encounter patients with substance-abuse problems. Alcoholism and drug abuse, with their associated psychosocial and clinical ramifications and complications, cut across all specialty fields. Consequently, all physicians need to be familiar with the spectrum of clinical problems associated with substance abuse and comfortable with addressing these problems prudently and promptly.

Cardiovascular Diseases↗
PubMed1992

Clarification of the dual task dilemma: lateralized effects for perfunctory and purposeful tasks in left- and right-handed males.

The hypothesis that behavioral asymmetries with the dual task paradigm represent manual dominance was investigated with right- and left-handed males performing verbal and spatial tasks ordered by complexity. Lateralization was assessed for nonideational (perfunctory) and ideational (purposeful) components of tasks with multivariate and ANCOVA procedures. The outcomes of prerequisite tests showed the assumptions for conducting ANCOVA procedures were not satisfied with different handedness groups in the same design. However, results of the multivariate analyses suggest lateralized effects are more likely to represent the cognitive task when interference is high and may represent manual dominance when interference is low.

Adult↗
PubMed1991

Psychosocial impacts in populations exposed to solid waste facilities.

This interdisciplinary study uses a parallel case study design to investigate psychosocial impacts in populations exposed to three solid waste facilities in Southern Ontario. Impacts are examined at three social scales: individual, social network and community levels. The objectives and design derive from a feasibility study recently completed by the same research team. A two stage approach is adopted. The first is an epidemiologic survey to determine the prevalence of psychosocial impacts in the populations within a prescribed area around each site. A disproportionate stratified (by distance) random sample of 250 households is surveyed at each site. Data on awareness, knowledge, concern and action regarding the site are also obtained. Scores on pre-validated health measurement scales will be compared with population norms to determine the frequency distribution above, within and below the range of normal. The second stage involves the use of qualitative methodologies to provide an in-depth analysis of the individual, social network and community level factors affecting psychosocial impacts and reactions to the situation. Depth interviews with a sub-sample of survey respondents explore individual perceptions, attitudes and actions. Focus groups composed of members of relevant organizations and discussion groups comprising non-members uncover social network and community perspectives in an interactional setting. Interviews and group sessions are taped and transcribed for content analysis of salient themes. Textual analysis of media reports and other relevant documentation provide insights regarding the informational environment and the community context of the issues.

Adaptation, Psychological↗
PubMed1991

Therapy for women hospitalized with acute pyelonephritis: a randomized trial of ampicillin versus trimethoprim-sulfamethoxazole for 14 days.

The efficacy of the traditionally recommended ampicillin (Amp) plus gentamicin (GM) regimen was compared with that of a trimethoprim-sulfamethoxazole (TMP/SMZ)-plus-GM regimen and the adequacy of 14 days total therapy for acute uncomplicated pyelonephritis (AUPN). Eighty-five women hospitalized for AUPN were randomly assigned to receive either Amp, 1 g intravenously (iv) every 6 h for 3 days, then 500 mg orally four times daily, or TMP/SMZ, 160/800 mg iv every 12 h for 3 days, then 160/800 mg orally twice daily. Initially, all patients also received GM every 8 h iv (mean, 606 doses). Antimicrobial resistance necessitated modifying therapy of 14 (32%) of the Amp recipients but of none of the TMP/SMZ recipients (P less than .001). Both regimens produced a satisfactory bacteriologic and clinical response in all cases. Reinfection occurred in 11% of Amp and in 8% of TMP/SMZ recipients. No patient experienced relapsing infection. The TMP/SMZ regimen was less costly and less likely to require modification due to antimicrobial resistance.

Acute Disease↗
PubMed1991

Serological assessment of chlamydial infection in the koala by a slide EIA technique.

A rapid and simplified slide enzyme immunosorbent assay (EIA) was developed for the diagnosis of chlamydial infection in the koala. HeLa 229 cells infected with koala strain Chlamydia psittaci were fixed on the surface of multiwell slides and used as the antigen. The assay consisted of first reacting koala antiserum with the fixed C psittaci antigen, followed by reaction with biotinylated rabbit anti-koala IgG, ABC reagent and substrate. The chlamydial EIA antibody titres obtained were compared with those of a complement fixation (CF) test using koala strain C psittaci as antigen. Of 35 koala sera tested, 16 CF positive sera (greater than or equal to 1:8) also had a positive titre (greater than or equal to 1:200) in the slide EIA test (sensitivity 93.8%, 15/16). Nineteen CF negative sera were also negative in the slide EIA (specificity 100%, 19/19). Sixty-eight samples of koala blood were collected by ear-prick using a sampling paper method and were assayed by both tests. Sensitivity of the slide EIA was 100% (15/15) and specificity of the test was 96.2% (51/53). To simplify the slide EIA for use as a practical screening test, a 3-point serum dilution series (1:100, 1:200, 1:400) was used. This 3-point slide EIA was compared with the CF test using sheep strain chlamydial antigen. Thirty-nine sera were assayed by both tests. The sensitivity of the 3-point method was 85.7% (6/7) and the specificity was 71.9% (23/32) as compared with the sheep antigen CF test.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Blood culture techniques for the diagnosis of melioidosis.

The effects of variations in laboratory technique on the speed and sensitivity of isolation of Pseudomonas pseudomallei from blood were evaluated prospectively. Pseudomonas pseudomallei was isolated from 154 of 546 cultures from 325 patients with suspected or confirmed melioidosis. Subcultures after 12 to 24 and 36 to 48 hours of incubation were positive in 52.3% and 80.8% respectively. The yields from 20 ml (blood to broth ratio 1:4) and 50 ml (blood to broth ratio 1:10) brain heart infusion broth bottles were equivalent in patients not receiving treatment for melioidosis. During therapy, the 50 ml bottles grew Pseudomonas pseudomallei significantly faster than the 20 ml bottles (p less than 0.01), and gave a higher overall yield for cultures processed in antimicrobial removal devices (p less than 0.05). These devices themselves increased the speed of isolation of the organism from treated patients (p less than 0.01). In most cases, all bottles collected from a patient before treatment were positive, and a single 20 ml bottle had an estimated relative sensitivity of 85.7% (95% confidence interval 77.1-94.3%). Early subculture should be employed routinely for the laboratory diagnosis of septicaemic melioidosis. However, blood culture techniques do not need to be sophisticated. Culture of 5 ml blood in 20 ml broth is a simple and sensitive procedure suitable for regions where melioidosis is currently under-diagnosed.

Bacteriological Techniques↗
PubMed1990

Hemispheric involvement in shadowing vs. interpretation: a time-sharing study of simultaneous interpreters with matched bilingual and monolingual controls.

A time-sharing study used shadowing and interpretation/paraphrasing tasks to evaluate lateralization in professional interpreters individually matched to bilingual and monolingual controls. A two-step multivariate general linear model procedure was used to determine lateralized effects and extent of disruption produced by the tasks. Results revealed the monolingual group to be left lateralized for both tasks, but the two bilingual groups were lateralized in the LH only for shadowing. The monolingual group was significantly different from the bilingual groups in the pattern of hand asymmetry for interpretation/paraphrasing. The findings replicate outcomes of prior repeated measures analysis of variance procedures on percentage of change scores. However, new information is added by the more refined analysis. The findings are also discussed in terms of previous laterality studies using similar tasks and subject samples.

Adult↗
PubMed1990

The risk approach in diarrheal disease intervention in Grenada.

In a previous paper (Soc. Sci. Med. 23, 995-1002, 1986), we described the development of a method for identifying households at high risk of childhood diarrhea based on a logit analysis of data collected as part of a diarrhea disease control project in Grenada. In this paper, we report the results of a follow-up study designed to replicate the first using data on diarrhea incidence and risk factors collected in a different set of rural communities in Grenada. The findings of the first study were not replicated. There was no significant association between the risk factors and diarrhea in the follow-up study in contrast to the very strong associations found in the first study. As a consequence, it was not possible to construct a logit model from the second data set. The possible reasons for the contrasting sets of results and their implications for the application of the risk approach are discussed with reference to a two by two true-false table.

Diarrhea↗
PubMed1990

Decreased sex hormone binding globulin (SHBG) and insulin-like growth factor binding protein (IGFBP-1) in extreme obesity.

Obesity may be characterized by abnormal sex steroid secretion and reduced sex hormone binding globulin (SHBG) which in turn is related to fat distribution and insulin secretion. Recent in-vitro and in-vivo evidence suggests that insulin is the common mechanism regulating the secretion of SHBG and insulin-like growth factor small binding protein (IGFBP-1). IGFBP-1 appears not only to be a carrier for insulin growth factors (IGFs) but also to play an active role in growth processes, independent of growth hormone secretion. We have examined the possible relationship between fasting insulin, SHBG, testosterone, IGF-1, IGFBP-1 and fat distribution in 25 extremely obese, menstruating women (mean weight 107 +/- 3 kg) with normal glucose tolerance. Fat distribution was assessed from measurements of the waist to hip ratio (W/H). The obese women showed an elevated fasting insulin (mean +/- SEM; 21 +/- 2 mumol/l), a normal IGF-1, but reduced IGFBP-1 (14.6 +/- 2 micrograms/l); in 15 women IGFBP-1 levels were undetectable by the present assay. In addition, SHBG levels were reduced in the obese women (24 +/- 2 nmol/l) but total testosterone values (1.9 +/- 0.1 nmol/l) were normal. The elevated fasting insulin levels were positively correlated with increasing upper segment obesity as expressed by a rising W/H ratio (P less than 0.01, r2 = 0.306) and inversely correlated with SHBG (P less than 0.01, r2 = 0.483). Similarly, reduced SHBG values showed an inverse correlation with increasing W/H ratio (P less than 0.001, r2 = 0.383). No correlation was found between IGFBP-1 and W/H ratio but a strong positive correlation was seen between IGFBP-1 and SHBG (P less than 0.001, r2 = 0.466). Furthermore, an equally significant inverse correlation was found between IGFBP-1 and insulin levels (P less than 0.001, r2 = 0.474).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1990

The use of luteinising hormone releasing hormone and its analogues for induction of ovulation and ovarian stimulation for in-vitro fertilisation.

The use of subcutaneous pulsatile luteinising hormone releasing hormone (LHRH) for induction of ovulation in patients with hypogonadotrophic hypogonadism is efficacious and safer compared to human menopausal gonadotrophin (hMG) because of the lower risk of ovarian hyperstimulation and multiple pregnancy. In clomiphene citrate (CC) nonresponsive cases of polycystic ovarian disease (PCOD), the major advantage of pulsatile LHRH is that when ovulation occurs, it is usually uni-follicular. In cases of PCOD, we have found that if pulsatile LHRH alone fails to induce ovulation, addition of clomiphene citrate or a small dose of follicle stimulating hormone (FSH) will augment its action and allow, in the majority of cases, the threshold of stimulation to be reached that would be sufficient to induce ovulation but not produce clinical hyperstimulation or multiple pregnancy. LHRH analogues to desensitise the pituitary prior to ovarian stimulation with hMG have been recently used in in-vitro fertilisation (IVF). We have compared the use of the LHRH analogue, buserelin (Hoechst, UK) + hMG with clomiphene + hMG for ovarian stimulation in IVF in a number of prospective studies. In this review, the role of pituitary desensitisation in IVF is discussed in the light of our results. We have found that although the mean number of oocytes, the implantation rate and pregnancy rate per embryo transfer are higher in patients who receive buserelin + hMG, the differences are not statistically significant. The length of time taken to achieve pituitary desensitisation is increased in patients who have PCOD or who form ovarian cysts in response to the administration of buserelin.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1990

Body composition by photon absorptiometry.

Whole-body dual photon measurements of body composition were made in 9 controls, 15 athletes and 5 patients with eating disorders. Measurements of lean body mass, mineral mass and fat mass were accurate. Lean body mass and fat mass were measured with reliabilities of about 0.8 kg while for total body bone mineral mass, the reliability was about 60 g. Women had a smaller lean body mass and a greater fat mass than men. Women with eating disorders had the same body composition as males. Measurements of body composition by dual photon absorptiometry are safe and reliable.

Absorptiometry, Photon↗
PubMed1989

Recent advances in biological imaging.

Recent innovations in microscopy and digital image processing have greatly enhanced the power of biological imaging. Basic principles of several new methods in light and electron microscopy will be discussed, and examples presented of their application to cell and molecular biology.

Freezing↗
PubMed1989

Confocal scanning microscopy: three-dimensional biological imaging.

Confocal scanning optical microscopy, arguably the most significant in biological light microscopy in this decade, enables one to obtain quantitative non-invasive optical sections through labelled biological specimens, virtually free from out-of-focus blur. A set of these optical sections collected at a series of focal levels through an object constitutes a three-dimensional image which may then be processed digitally for display as a computer reconstruction, a stereo pair or an animation sequence.

Animals↗