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Biomedical subjects

C Adair

Publications and source records attributed to C Adair.

At least 19 recordsLinked to original sources
PubMed2001

Antibodies to capsular polysaccharides of group B Streptococcus in pregnant Canadian women: relationship to colonization status and infection in the neonate.

In a cohort study of 1207 pregnant women in Alberta, Canada, the serotype distributions of vaginal-rectal group B Streptococcus (GBS) isolates were compared with all isolates from neonates with invasive GBS disease identified by population-based surveillance. Serum concentrations of Ia, Ib, II, III, and V capsular polysaccharide (CPS)-specific IgG also were determined, according to serotype of the vaginal-rectal colonizing GBS strain. GBS colonization was detected in 19.5% (235 of 1207) of women. Serotype III accounted for 20.6% (48 of 233) of colonizing strains available for typing but for 37% (27 of 73) of invasive isolates from neonates (P<.01). Maternal colonization with type III was least likely to be associated with moderate concentrations of III CPS-specific IgG. Serotype III GBS is more invasive than other serotypes in this population; this may be due, at least in part, to poor maternal type III CPS-specific antibody response.

Adult↗
PubMed2001

Population-based active surveillance for neonatal group B streptococcal infections in Alberta, Canada: implications for vaccine formulation.

BACKGROUND: Knowledge of circulating serotypes of group B Streptococcus (GBS) is important for formulation of vaccines. There are no Canadian data on the serotype distribution of neonatal GBS isolates. METHODS: Using a retrospective laboratory and health record survey between 1993 and 1994 (before introduction of Canadian prevention guidelines) and prospective active laboratory-based surveillance from 1995 to 1999 of all laboratories in Alberta, we identified 168 cases of invasive neonatal GBS infections including stillbirths among 262,398 total births; 118 of 123 (96%) isolates from 1995 to 1999 were serotyped, and the corresponding neonatal health records were reviewed. RESULTS: The average annual incidence was 0.64 of 1000 total births/year. Of these 95 (57%) had early onset disease (EOD), 15 (9%) were still births and 58 (34%) had late onset disease (LOD). Eighty-one percent of EOD cases were caused by serotypes Ia, Ia/c, Ia/c/R, III, III/R and V, V/R, whereas 81% of LOD cases were caused by serotypes III and III/R. GBS serotypes containing the C protein along with serotypes III and V as a group constituted 91% (107 of 118) of all GBS cases in our population. The most common clinical presentation was bacteremia without focus (74%) followed by meningitis (14%) and pneumonia (12%). During 1995 to 1999, in addition to 13 stillbirths, there were 6 of 64 (9%) neonatal deaths among EOD cases and 1 of 46 (2%) neonatal death among LOD cases. CONCLUSIONS: In this population-based study stillbirths account for a proportion of cases that are not routinely counted and represent a group for which intrapartum antibiotics would likely not be effective, but potentially preventable by vaccination. Inclusion of serotypes Ia, III and V in a conjugate vaccine or serotypes III and V conjugated with the C protein in a GBS vaccine could theoretically provide protection against the majority of GBS invasive disease in Alberta neonates.

Alberta↗
PubMed2000

Cystic fibrosis. End-stage care in Canada.

OBJECTIVES: To determine the circumstances in which individuals with cystic fibrosis (CF) die, the role of different caregivers, and the extent of palliative care for CF patients. DESIGN: Mailed survey of CF physicians. SETTING: CF centers in Canada. PATIENTS: All CF deaths in 1996 known to centers in Canada. RESULTS: The mean age (+/- SD) at death of the 45 individuals included in the study was 25.8 +/- 13.5 years. The major cause of death was respiratory (34 patients; 75.5%). Nutritional concerns were common. Lung transplantation was considered in 42 patients (93.2%), with 7 patients (17.1%) being entered on a list, but it was carried out in only 2 patients (4.4%). Autopsies were performed on only 10 patients (22.2%). Most patients died in hospital (37 patients; 82.2%), and 7 patients (15.6%) died in ICUs while receiving intermittent positive-pressure ventilation. Palliative care was never discussed in 10 patients (25%). In a further 16 patients (40%), it was not discussed until the last month before death. CONCLUSIONS: Respiratory disease remains the most common cause of death in CF patients. Lung transplantation is frequently considered, but most patients die without having had a transplant. Discussions on end-of-life care could be considered sooner.

Adult↗
PubMed2000

Bacterial thermal death kinetics based on probability distributions: the heat destruction of Clostridium botulinum and Salmonella Bedford.

Despite the long history and excellent record of inactivation models used in thermal processing, there are relatively few approaches that attempt to describe the kinetics commonly observed. There are even fewer examples of models that allow the user to deal with the environmental conditions that influence these kinetics. We describe an approach that assumes a distribution of inactivation times within a population of bacterial cells. The concept allows for alternative interpretations of death kinetics and provides excellent descriptions of data generated with two important foodborne pathogens, Clostridium botulinum and Salmonella Bedford. The Salmonella Bedford data set used is unusual and perhaps unique in that it provides information where more than 50% of the population survival has been measured. These measurements are often overlooked or missed in experimental work but are essential when using a vitalistic approach, enabling calculation of a 50% lethal dose for destruction of bacteria. Use of the normal or Prentice distribution provided better fits to the data than other models commonly used to describe thermal death. There was no obvious bias in the fits even though significant tailing was evident. In addition, the procedure described allows data from all the conditions to be fitted rather than individual independent series. This enables a single equation to be derived that can be judged against the whole domain of the data. Approaches that provide accurate and unbiased descriptions of thermal death are likely to become increasingly important to ensure the safety of more marginal heat processes.

Clostridium botulinum↗
PubMed1999

Fluorescent tissue site-selective lanthanide chelate, Tb-PCTMB for enhanced imaging of cancer.

In-vivo and in-vitro investigations indicate that a newly developed polyazamacrocyclic chelate of Tb(III) has superior properties for use as an abnormal tissue marker. In addition to tissue selectivity, this molecule is unique because of its low toxicity, attractive fluorescent properties, rapid pharmokinetics, and relatively high water solubility. The complex Tb-3,6,9-tris(methylene phosphonic acid n-butyl ester)-3,6,9,15-tetraazabicyclo[9.3.1]-pentadeca-1(15),11,13 -triene (Tb-PCTMB) has also been shown to exhibit strongly shifted emission (delta lambda--280 nm), moving the detection frequency away from autofluorescence backgrounds, and good quantum efficiencies (phi = 0.51), providing high brightness. Fluorescence imaging was used to quantify Tb-PCTMB at the picomolar level in tissues and to show the significant difference in affinity for the chelate by adenocarcinoma cells HT-29 versus normal epithelial cells (IEC-6). Topical application, or lavage introduction, under endoscopy was used to instill a millimolar aqueous solution of Tb-PCTMB into a dimethylhydrizene-treated Sprague Dawley rat large intestine containing a suspect growth. Subsequent in vitro fluorescence detection and standard histological evaluation confirmed enhanced uptake by adenocarcinoma tissue. Semiquantitative signal interrogation was employed to show the potential for using Tb-PCTMB as a contrast enhancement marker for disease detection.

Animals↗
PubMed1998

The impact of initial surgical management on outcome in young patients with differentiated thyroid cancer.

BACKGROUND/PURPOSE: It is generally believed that differentiated thyroid cancer (DTC) in young patients has an excellent prognosis. This calls into question the need for more extensive surgical ablation of the thyroid gland with attendant risks of surgical complications. The purpose of this report was to investigate both the incidence of surgical morbidity and the impact of surgery on locoregional recurrence of disease. METHODS: The authors reviewed the clinical course of patients under 22 years of age treated for DTC within Department of Defense hospitals since 1950. Data were available for determination of surgical morbidity in 126 and for outcome in 105. RESULTS: The incidence of postoperative hypocalcemia was 17% and of recurrent laryngeal nerve injury 3%. Factors predictive of morbidity were (1) more extensive thyroid surgery (P = .023), and (2) the presence of gross tumor invasion (P = .022). The incidence of neck recurrence was analyzed among a cohort of 90 patients. A total of 19 (21%) patients had a local recurrence. The median time to recurrence was 24 months. The factor predictive of recurrence was the presence of gross invasion (P = .0001). A strong trend toward locoregional recurrence was found among patients with metastatic disease to more than five cervical nodes (P < .08). The primary operations on the thyroid and regional nodes were not significant predictors of neck recurrence. Among these 19 patients there have been no deaths, but 25% had persistent disease at a mean follow-up of 12.6 years. CONCLUSIONS: The incidence of surgical morbidity does increase with more extensive surgery. Outcome is predicted primarily by the initial extent of disease.

Adolescent↗
PubMed1998

Clinical features associated with metastasis and recurrence of differentiated thyroid cancer in children, adolescents and young adults.

OBJECTIVE: Differentiated thyroid cancer (DTC), including papillary (PTC) and follicular (FTC) variants, is unusual in children and accounts for only 10% of all cases. For that reason, knowledge of the clinical features which predict recurrence is limited. We reviewed 170 cases of childhood DTC to determine if specific clinical or pathological findings were associated with increased risk of recurrence. DESIGN: This was a retrospective study of children and adolescents with DTC registered in the Department of Defense Automated Centralized Tumor Registry. PATIENTS: We reviewed 137 cases of PTC and 33 cases of FTC diagnosed between 1953 and 1996 at < or = 21 years of age. RESULTS: In the PTC group (median follow-up 6.6 years, range 2 month-39.5 years), only one patient died, but 21 developed local and 6 developed distant recurrence. By univariate analysis, recurrence was more common in patients with multifocal (odds ratio 7.5) or large tumours (odds ratio 4.1), and in those with palpable cervical lymphadenopathy (odds ratio 3.0) or metastasis at diagnosis (odds ratio 2.8). By multivariate analysis focality was the best predictor of recurrence (P = 0.0019). In the FTC group (median follow-up 5 years, range 6 month-38.1 years), no patient died of disease, but 5 developed recurrence. As with PTC, recurrence was more likely in patients with multifocal tumours (odds ratio 22.0). CONCLUSIONS: Differentiated thyroid cancer in children and adolescents has low mortality, but a high risk of recurrence. Young patients with large, multifocal tumours that are already metastatic at diagnosis have the greatest risk of recurrence.

Adenocarcinoma, Follicular↗
PubMed1998

Zinc may regulate serum leptin concentrations in humans.

OBJECTIVE: Leptin, the product of the ob gene, plays a key role in a feedback loop that maintains energy balance by signaling the state of energy stores to the brain and by influencing the regulation of appetite and energy metabolism. Zinc also plays an important role in appetite regulation. Thus, we evaluated the relationship between zinc status and the leptin system in humans. METHODS: We studied nine healthy men with marginal zinc deficiency, induced by dietary means, before and after zinc supplementation. RESULTS: Zinc restriction decreased leptin levels while zinc supplementation of zinc-depleted subjects increased circulating leptin levels. In addition, zinc supplementation increased IL-2 and TNF-alpha production that could be responsible for the observed increase in leptin concentrations. CONCLUSIONS: Zinc may influence serum leptin levels, possibly by increasing the production of IL-2 and TNF-alpha.

Adult↗
PubMed1998

Quantitative microbiological risk assessment: principles applied to determining the comparative risk of salmonellosis from chicken products.

Ensuring microbiological safety requires identification of realistic hazards and the means of controlling them. The risk assessment framework proposed by Codex Alimentarius allows the impact of raw materials and processes to be appreciated, and the output can be used for risk management and communication. Mathematical models allow numerical information to be processed by a computer and interpreted to give quantitative or comparative risk assessments. In this example, models have been put together according to the Codex. Alimentarius principles, providing a quantitative risk assessment (QRA) of salmonellosis from frozen poultry products. This model-based QRA takes into account three types of information: occurrence and distribution of the agent, sensitivity of populations to infection (e.g., normal or susceptible), and the effect of cooking (in the factory or home) on concentration of the agent and hence risks of infection after product consumption. It only demonstrates the impact of a single-process step (heating) and the effect of changes in population sensitivity, raw material quality, and cooking regime on the final risk. The effects of growth and recontamination are not considered. To aid risk communication, the models have been visualized by means of displays and slider controls on a computer screen because effective communication is essential to encourage manufacturers and their product designers to assess the effect of changes in processing or materials on risk.

Adult↗
PubMed1997

The effect of temperature on the germination of single spores of Clostridium botulinum 62A.

Phase-contrast microscopy coupled with image analysis has been used to study the germination of single spores of Clostridium botulinum and to investigate the variation of germination lag of individual spores in a population (biovariability). The experiment was repeated at five different temperatures between 20 degrees C and 37 degrees C to look at the effect of temperature on the biovaribility of the spore germination. Data analysis shows that the germination lag distribution is skewed, with a tail, and that its shape is affected by the temperature. The origin of this biovariability is not exactly known, but could be due to a distribution of characteristics (e.g. permeabilities) or molecules (e.g. lytic enzymes) in the spore population. The method developed in this study will help us to describe and better understand the kinetics of spore germination and how this is influence by different environmental factors such as temperature and other factors that influence germination.

Bacteriological Techniques↗
PubMed1993

Influence of selective decontamination of the digestive tract on microbial biofilm formation on endotracheal tubes from artificially ventilated patients.

The effect of selective decontamination of the digestive tract on the nature and incidence of microbial biofilm formation on endotracheal tubes was assessed. Thirty endotracheal tubes were obtained post-extubation from patients in the intensive care unit who had been ventilated for a 1 to 15 day period and who did or did not receive the antibiotic regimen. Extensive biofilm formation was identified by scanning electron microscopy on 97% of tubes examined. Endotracheal tube biofilm in tubes obtained from patients who received selective decontamination of the digestive tract showed a high prevalence of colonization with yeast (4 of 15 tubes) and gram-positive bacteria (streptococci, staphylococci and diphtheroids) (14 of 15 tubes). Staphylococcus aureus was isolated only from this group. Pseudomonas spp. were isolated from 2 of 15 tubes in both patient groups. Enteric gram-negative organisms (coliforms, Klebsiella and Proteus spp.) were isolated only from tubes of patients who did not receive the antibiotic regimen (4 of 15 tubes). Yeasts, however, were not isolated from these tubes. Group D streptococcal isolates were resistant to tobramycin as were half of the Staphylococcus aureus isolates. For gram-negative bacteria, the MIC of tobramycin was in the range 1-64 micrograms/ml and the MIC of polymyxin in the range 0.5-16 micrograms/ml. Although a reduction was observed in the incidence of gram-negative microorganisms, this antibiotic regimen does not inhibit biofilm formation on the endotracheal tube by other pathogens associated with pneumonia in ventilated patients. This persistent nidus may be a factor in the pathogenesis of nosocomial pneumonia.

Adolescent↗
PubMed1992

The parasympathetic system in exercise-induced rhinorrhoea.

The present study demonstrates that ipratropium bromide significantly reduces normal resting nasal secretion (p less than 0.05) and also significantly reduces exercise induced rhinorrhoea compared with a placebo (p less than 0.01). It also demonstrates that there may be another non-parasympathetic cause for the increase in nasal secretion with exercise.

Adult↗
PubMed1988

Nitrogen losses and cephalothin absorption in peritonitis treated by hourly peritoneal dialysis.

The effects of peritonitis on dialysate nitrogen losses were investigated. Eight patients who developed peritonitis while undergoing peritoneal dialysis were compared to seven noninfected dialysis patients. Dialysate protein losses increased during peritonitis, but nitrogen losses into the dialysate did not increase. These findings were caused by reduced urea nitrogen losses in the peritonitis group, which proportionately, more than made up for the increased nitrogen losses from protein. We speculate that the smaller loss of urea nitrogen was due to diminished intake of food. Cephalothin uptake from the peritoneal cavity was unaltered by peritonitis and a dialysate flow rate of 2 L/hour averaged 26 +/- 2 mL/minute and 27 +/- 2 mL/minute in the noninfected and infected groups, respectively.

Absorption↗
PubMed1986

Protein losses and tobramycin absorption in peritonitis treated by hourly peritoneal dialysis.

The effects of peritonitis on dialysate protein losses of IgG, IgA, IgM, transferrin, and complement were investigated. Thirteen patients who developed peritonitis while undergoing peritoneal dialysis were compared with seven noninfected dialysis patients. Dialysate protein losses increased during peritonitis, but IgG, IgA, IgM, transferrin, and complement losses did not. The ratio of the amount of these proteins to the total amount of protein, measured by trichloroacetic acid precipitation, was unaltered by peritonitis, suggesting that albumin is the predominant protein lost during peritonitis. The infected patients absorbed 55% of the administered dose of tobramycin, at 17 mL/min, and the noninfected 44%, at 13 mL/min.

Adolescent↗
PubMed1986

Effect of intraperitoneal insulin on solute kinetics in CAPD: insulin kinetics in CAPD.

The authors evaluated the transport kinetics of insulin and inulin administered intraperitoneally to six diabetic patients undergoing continuous ambulatory peritoneal dialysis. The mass transfer coefficients (MTC) calculated from dialysate to blood for 1.5% and 4.25% dextrose dialysate were (ml/min): insulin 2.9 +/- 0.9, 2.0 +/- 0.5; inulin 3.3 +/- 1.4; 2.9 +/- 1.7, respectively. The MTC for inulin calculated from blood to dialysate was 2.0 +/- 0.7 ml/min. Because insulin disappears from the peritoneal cavity at a rate similar to inulin, it suggests that insulin transport can be defined by diffusion. The derived MTC values for glucose were not altered by the addition of intraperitoneal insulin. The derived MTCs for eight diabetic to thirteen nondiabetic patients were compared. The MTC derived for urea was less among the diabetics (16.6 +/- 2.2 vs. 24.6 +/- 2.6 p less than 0.05), but there were no differences for creatinine, uric acid, glucose, inulin, and protein. The derived values were found to be normally distributed and patients in the upper quartile for one solute were generally in the upper quartile for other solutes.

Ascitic Fluid↗
PubMed1985

A double blind trial of dipyridamole in CAPD.

Since we had previously shown that dipyridamole augmented inulin and glucose clearance during intermittent peritoneal dialysis we sought to extend our study to the patient undergoing continuous ambulatory peritoneal dialysis. We carried out a double blind study in which patients received either 75 mg of active drug or placebo for a 2-week period. At the end of this period the mass transfer coefficients, between plasma and dialysate, were measured for selected solutes. We did not find any drug effect. The results of our first study together with the results of this study suggest that dipyridamole has no place in the chronic management of patients undergoing peritoneal dialysis.

Administration, Oral↗