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Biomedical subjects

S Bartlett

Publications and source records attributed to S Bartlett.

At least 19 recordsLinked to original sources
PubMed1998

Posttransplantation lymphoproliferative disorder associated with OKT3 and decreased antiviral prophylaxis in pancreas transplant recipients.

Between September 1994 and October 1995, we diagnosed and treated four cases of early onset posttransplantation lymphoproliferative disorder (PTLD) occurring within 62 days of pancreas transplantation. The development of PTLD was associated with both a significantly higher total muromonab-CD3 (OKT3) dose and a lack of ganciclovir/acyclovir prophylaxis, but it was not associated with the total dose of antithymocyte globulin or cytomegalovirus serostatus. All four patients were treated aggressively and survived without evidence of recurrent PTLD more than 1.5 years later. We conclude that the use of a high total dose of OKT3 puts pancreas transplant recipients at increased risk for early onset PTLD, while ganciclovir/acyclovir prophylaxis may help to prevent this disorder; however, if early onset PTLD does occur in these patients, aggressive therapy can lead to a favorable outcome.

Acyclovir↗
PubMed1997

Expression of stress proteins heme oxygenase-1 and -2 in acute pancreatitis and pancreatic islet betaTC3 and acinar AR42J cells.

Oxygen-derived free radicals have been implicated in the pathogenesis of acute pancreatitis, yet adaptive responses in the pancreas in vivo to oxidative stress remain poorly defined. We have investigated expression of the stress protein heme oxygenase in the intact pancreas of rats with caerulein-induced pancreatitis and in cultured pancreatic acinar and islet cell lines. Expression of inducible heme oxygenase-1 (HO-1) in the pancreas in vivo was enhanced 12-24 h after induction of pancreatitis. In murine islet (betaTC3) and rat acinar (AR42J) pancreatic cells, H2O2, methyl viologen, cadmium chloride and diethylmaleate enhanced HO-1 expression in a dose- and time-dependent manner, without altering expression of constitutive HO-2. Enhanced expression of HO-1 in the pancreas in vivo and pancreatic islet and acinar cells may contribute to cellular defences against oxidative stress associated with acute pancreatitis.

Animals↗
PubMed1995

Critical review of microfixation in pediatric craniofacial surgery.

The migration or passive intracranial translocation of microplates and screws in the pediatric craniofacial patient has been reported. A retrospective review was undertaken to clarify the incidence of microplate translocation and identify potential clinical implications. Computed tomographic imaging demonstrated internalization of microfixation in 14 of 27 pediatric patients. Statistically significant factors for microplate translocation include longer plates (p < 0.05) and those placed in the temporal region (p < 0.001). Younger patients and those with syndromic craniofacial dysostosis also had a higher incidence of translocation. Specific complications relating to the translocation of microplates were not found in any patient. The direct effects of translocated microplates and screws on the underlying brain and dura remain unclear.

Bone Plates↗
PubMed1995

Uncertainty, variability, and sensitivity analysis in physiological pharmacokinetic models.

Physiologically based pharmacokinetic (PBPK) models are now commonly used to predict the dose of toxic metabolites of chemical substances reaching target tissues. A typical PBPK model can involve 20 or more physiological, physiochemical, and biochemical parameters, each of which is estimated with some degree of error. In this article, methods for assessing the impact of uncertainty in the parameter values on prediction of tissue dose are proposed, along with methods for identifying those parameters to which predictions of tissue doses are most sensitive. Many of the model parameters are related to body weight, which is assumed to vary in accordance with a doubly truncated normal distribution. The application of the proposed methods is illustrated using a PBPK model for benzene.

Animals↗
PubMed1993

Contamination of human ovarian follicular fluid and serum by chlorinated organic compounds in three Canadian cities.

OBJECTIVES: To determine the extent of contamination of ovarian follicular fluid and serum samples in women undergoing in-vitro fertilization and to study the effect of the contaminants on reproductive outcome. DESIGN: Inception cohort study. PATIENTS: Seventy-four women undergoing in-vitro fertilization at three regional clinics in Halifax, Hamilton, Ont., and Vancouver. MAIN OUTCOME MEASURES: Follicular fluid and serum levels of contaminants, cleavage rates and time to cleavage of first egg. RESULTS: Five chlorinated organic chemicals were frequently found in the two types of samples: alpha-chlordane (ALCH), dichlorochlorophenylethylene (DDE), heptachloroepoxide-oxychlordane (OXCH), hexachlorobenzene (HCB) and polychlorinated biphenyl (PCB). The levels were generally low. Regional differences between the three clinics were present. Samples from the Halifax clinic had the lowest frequency and level of contamination. The source of drinking water (well, bottled or municipal) was an important confounder. The concentrations of the five contaminants did not affect the cleavage rate or the time to cleavage of the first egg. CONCLUSION: Trace amounts of toxic and persistent chlorinated organic chemicals found in the follicular fluid of Canadian women undergoing in-vitro fertilization did not seem to have any adverse biologic effect on the rate of fertilization and the time to cleavage. Reasons for regional differences in the concentrations of contaminants require further study.

British Columbia↗
PubMed1993

Hexachlorobenzene toxicity in the monkey primordial germ cell without induced porphyria.

Hexachlorobenzene is a persistent chlorinated organic chemical that has been detected in many tissues from a variety of species including human ovary and human ovarian follicular fluid. When administered in high dosage to nonhuman primates, hexachlorobenzene causes destruction of ovarian primordial germ cells in association with systemic toxicity. The purpose of these experiments was to assess relative ovarian germ cell sensitivity at much lower dosages of hexachlorobenzene that do not produce systemic effects and additionally to evaluate oocyte function by means of the response to superovulation, fertilization, and embryo cleavage during a cycle of in vitro fertilization in the cynomolgus monkey. Hexachlorobenzene in dosages of 0.1, 1.0, and 10.0 mg/kg/day was administered orally by gelatin capsule for 90 days. There was a dose-dependent accumulation of HCB in serum and other tissues without any change in the serum estradiol response to human menopausal gonadotropin, oocyte recovery, oocyte maturation, oocyte fertilization in vitro, and early embryo cleavage rate. There was a dose-related toxic effect observed in primordial germ cells at the lowest dose despite no evidence of systemic or hepatic effects. As there were no changes in the urinary porphyrin excretion, the mechanism of hexachlorobenzene ovotoxicity may be distinct from hexachlorobenzene-induced cytochrome P-450-dependent inhibition of uroporphobilinogen decarboxylase in the liver, although such intraovarian metabolism cannot be excluded.

Animals↗
PubMed1992

Relationship of dieting history to resting metabolic rate, body composition, eating behavior, and subsequent weight loss.

This study examined the relationship of dieting history to resting metabolic rate, body composition, and subsequent weight loss in 50 obese women. A preliminary study showed that the women were able to report with satisfactory reliability the number of diets in which they had engaged (mean = 4.9 +/- 0.5), as well as the total weight loss resulting from these diets (mean = 55.9 +/- 6.0 kg). We found no evidence that weight cycling, as measured by either of these variables, was associated at baseline with a reduced resting metabolic rate or an increased percentage of body fat. Nor did we find that weight cycling was associated with smaller weight losses in a prospective trial in which subjects were treated by very-low-calorie diet and behavior therapy. The clinical implications of these findings are discussed, as are the methodological problems encountered in conducting research on this topic.

Adipose Tissue↗
PubMed1991

Protein metabolism after abdominal surgery: effect of 24-h extradural block with local anaesthetic.

We have studied the effect of intraoperative and postoperative (24 h) extradural block with local anaesthetic on whole body protein turnover (stable isotope methodology) and urinary excretion of urea nitrogen, adrenaline, noradrenaline and cortisol in a group of well nourished elderly patients undergoing colorectal surgery who received a constant nutritional intake before (7 days) and after (4 days) surgery. One group (control, n = 8) received routine anaesthetic and surgical care. Patients in the test group (extradural, n = 9) received extradural bupivacaine, and sensory block (T4-S5) was maintained during and after surgery for a period of 24 h. Whole body protein breakdown and amino acid oxidation increased significantly after surgery in both groups (P less than 0.05), but the increase in protein breakdown in the extradural group was significantly less than that in the control group. Urinary excretion of urea nitrogen, adrenaline and noradrenaline increased in the control group after surgery, whilst the increase in the extradural group was very small. In contrast, urinary excretion of cortisol increased significantly in both groups after surgery. We conclude that extradural block maintained for 24 h after surgery significantly minimized postoperative protein breakdown without compromising whole body protein synthesis.

Abdomen↗
PubMed1991

Childhood asthma and the indoor environment.

To investigate the influence of indoor air quality on respiratory health, a questionnaire-based study of 17,962 Canadian schoolchildren in kindergarten through grade 2 was carried out in 1988. The present report focuses on associations between several indoor environmental factors and childhood asthma. Increased reports of physician-diagnosed asthma were significantly associated (p less than 0.001) with exposure to environmental tobacco smoke (OR = 1.4), living in a damp home (OR = 1.5), the use of gas for cooking (OR = 2.0) and the use of a humidifier (OR = 1.7). Wheezing without a diagnosis of asthma also was associated (p less than 0.01) with environmental tobacco smoke (OR = 1.4, home dampness (OR = 1.6) and humidifier use (OR = 1.4), but not with gas cooking. Thus, several modifiable risk factors for respiratory illness may exist in Canadian homes. Further research is required to determine the nature of these cross-sectional observations.

Air Pollution, Indoor↗
PubMed1990

Chorioretinal folds and a macular hole secondary to craniofacial surgery.

Chorioretinal folds have been reported as a result of many intraocular and extraocular inflammatory processes or tumors. Visual loss is usually secondary to a combination of the underlying process and chorioretinal folds involving the macula. We report a patient who developed decreased vision, metamorphopsia, chorioretinal folds, and a lamellar macular hole secondary to global compression by a bone fragment. The chorioretinal folds regressed and his vision stabilized following surgical decompression. Chorioretinal folds and lamellar macular hold formation are previously unrecognized complications of reconstructive craniofacial surgery.

Adult↗
PubMed1989

Increased plasma carnitine in severe alcohol dependence.

Carnitine plays a central role in lipid metabolism. There have been several suggestions that carnitine metabolism is affected in alcoholism. In the present study plasma carnitine levels in severely dependent alcoholic patients were investigated. The results show that total and free plasma carnitine in 11 out of 14 patients were raised above those found in normal control subjects. This may be indicative of changes central to the disease process. We suggest that plasma free carnitine represents a useful test which can be added to those currently used to assess alcohol dependence.

Adult↗
PubMed1987

Staged use of soft-tissue expansion and lower thoracic advancement flap in breast reconstruction.

A single patient is presented in whom breast reconstruction after mastectomy for breast cancer has been achieved by sequential use of soft-tissue expansion followed by permanent silicone implant placement and thoracic flap advancement to define the inframammary fold. This procedure may play a useful role in patients in whom other, more complex methods of breast reconstruction are not selected or indicated and in particular in patients in whom bilateral silicone implants are utilized.

Adult↗
PubMed1985

Shape sensing for computer aided below-knee prosthetic socket design.

Shape sensing is useful in the computer aided prosthetic fitting process for two purposes. 1. To input characteristic prosthetic shapes that have been developed over the years through the experience of prosthetists. 2. To provide an accurate and rapid measurement of the anatomical shape of the stump. This paper describes two instruments which have been built to meet these objectives.

Amputation Stumps↗