PubMed Health⌕ Search

Biomedical subjects

S Crawford

Publications and source records attributed to S Crawford.

At least 19 recordsLinked to original sources
PubMed2007

Platelet and leukocyte activation in salvaged blood and the effect of its reinfusion on the circulating blood.

Postoperative wound drainage reinfusion reduces the frequency of homologous blood transfusion. The salvaged blood is depleted of coagulation factors but may contain platelets and leukocytes which are activated, and therefore potentially procoagulant. We ascertained the degree of activation of platelets and leukocytes in salvaged blood and asked whether their infusion produced any measurable effect on patients' coagulation system. We prospectively randomized 24 patients who had total knee arthroplasties to reinfusion of salvaged autologous blood (n = 12) or a standard drain with no reinfusion (n = 12). Analysis of the salvaged blood showed marked activation of platelets as shown by their expression of P-selectin, CD40 ligand, and Factor V/Va, and as increased numbers of platelet-derived microparticles. After reinfusion there was no measurable effect on activation markers of circulating platelets or leukocytes but there was a decrease in platelet count in the reinfused group compared with the control group. Levels of prothrombin fragment F1 + 2 (suggesting thrombin formation) increased in the reinfused group compared with control group, possibly indicating activation of coagulation systemically. The platelets and leukocytes in salvaged blood are markedly activated and their reinfusion causes a decrease in platelet count in the recipient and a possible increase in thrombin generation potentially favoring thrombosis.

Aged↗
PubMed2006

PDA-assisted low glycemic index dietary intervention for type II diabetes: a pilot study.

BACKGROUND: Epidemiological and dietary intervention studies suggest that a low-glycemic index (GI) diet is beneficial for blood glucose control; however, long-term clinical utility of the low GI diet has not been fully investigated. OBJECTIVES: To evaluate the feasibility and efficacy of a nutritionist-delivered low-GI dietary intervention, with the support of a personal digital assistant (PDA), for adult patients with poorly controlled type II diabetes. METHOD: The low-GI intervention consisted of six counseling sessions and the use of a PDA-based food database with GI scores for 6 months. Study outcomes included feasibility measures, glycosylated hemoglobin levels (HbA1c), GI and glycemic load (GL) score of self-reported dietary intake, body weight, depression and quality of life (QOL). Measures were obtained at baseline, 3 and 6 months. RESULTS: Of 31 adult patients approached, 15 met study eligibility criteria and were enrolled in the study. Thirteen patients (87%) completed all study assessments. Findings included decreases in average HbA1c (-0.5% P = 0.02), body weight, hip circumference, blood pressure, dietary GI and daily caloric intake. Diabetes impact scores also decreased. All but one participant completed all components of the intervention. There were mixed reports regarding the usefulness of the PDAs; however, participants offered helpful suggestions for further development. CONCLUSIONS: Results of this pilot study support the feasibility of implementing a nutritionist-delivered, PDA-assisted low-GI dietary intervention for patients with poorly controlled type II diabetes. Encouraging initial efficacy data require further testing in the context of a randomized clinical trial.

Adult↗
PubMed2006

Comorbidity, co-occurrence, continuum: What's in a name?

BACKGROUND: Comorbidity, co-occurrence and continuum are three terms used when referring to developmental problems such as Developmental Coordination Disorder (DCD), but they can be confusing and misleading. Further, the terms can be upsetting to parents, and are not always helpful in guiding the selection of clinical interventions. GOALS: The main purpose of this paper is to question some of the terminology we employ when referring to DCD and other developmental problems. A secondary purpose is to discuss some of the conceptual frameworks that have been proposed that attempt to address the issue of the interrelationships among developmental problems. APPROACH: The terminology is examined by first referring to the basic dictionary definitions. Second, data we have published that relate to the issues of co-occurrence and continuum are reviewed in light of the terminology questions. Finally, we review some alternative conceptual frameworks which more accurately describe the relationships among developmental problems. CONCLUSION: The term 'comorbidity' has limited relevance to developmental problems, and its use is questionable. In contrast, co-occurrence and continuum are more useful terms to use in regard to developmental problems. Concepts such as atypical brain development and minor neurological dysfunction provide some possible explanations for the increased levels of co-occurrence of developmental disorders in children who are more severely affected.

Child↗
PubMed2006

Safeness of Simplex-tobramycin bone cement in patients with renal dysfunction undergoing total hip replacement.

PURPOSE: To compare the pharmacokinetic profile of tobramycin in blood, urine, and at the operative site following the use of Simplex-tobramycin bone cement in primary total hip replacement between patients with and without renal dysfunction. METHODS: Six patients with renal dysfunction underwent cemented primary total hip replacement for osteoarthritis. The elution characteristics of Simplex-tobramycin bone cement in the 6 patients with renal dysfunction were compared with 9 patients who had normal renal function. Blood, urine, and drainage fluid specimens were collected for 72 hours postoperatively. RESULTS: Very high concentrations of tobramycin were seen in the drainage fluid of the 2 groups. Mean serum tobramycin levels peaked at postoperative 3 hours, and declined rapidly to negligible levels at 72 hours in both groups. Mean urinary tobramycin concentrations peaked at postoperative 12 hours and declined rapidly until 48 hours in both groups. Urinary tobramycin was excreted significantly more slowly in renal dysfunction group in the first 12 hours, but not thereafter. Although serum creatinine levels of the renal dysfunction group were higher throughout the study period, the difference was not significant. Both groups achieved excellent local delivery of the antibiotic with minimal systemic concentrations. CONCLUSION: Simplex-tobramycin bone cement appears to be an effective and safe means to deliver antibiotic for patients with renal dysfunction who undergo total hip replacement.

Aged↗
PubMed2005

Aprotinin and epsilon aminocaproic acid are effective in reducing blood loss after primary total hip arthroplasty--a prospective randomized double-blind placebo-controlled study.

A prospective randomized double-blind placebo-controlled study was undertaken to determine the efficacy and mechanism of action of two antifibrinolytic drugs aprotinin and epsilon aminocaproic acid (EACA) in reducing blood loss in primary unilateral total hip arthroplasty (THA). Aprotinin was administered as a bolus of 2 x 10(6) kallikrein inhibitor units (KIU) followed by 0.5 x 10(6) KIU h(-1) for 3 h, EACA was given as 10 g over 30 min followed by 5 g over 3 h. The median postoperative blood loss 24 h postoperatively was reduced from 450 mL in the placebo group to 180 mL for aprotinin (60% reduction, P < 0.001) and to 210 mL for EACA (53% reduction, P < 0.01). In this population, there was no reduction in the perioperative transfusion requirements. The mechanism of both drugs was independent of platelets as indicated by flow cytometric measurement of change of their expression of P-selectin, platelet-monocyte aggregates, V/Va and CD40 ligand. There were no thrombotic or infective complications and no adverse events were attributable to use of either drug. Infusion of either aprotinin or EACA at the doses described is a safe and effective means of reducing blood loss after THA. These therapies provide a means of reducing blood loss in THA patients.

Aged↗
PubMed2005

Application of an improved method for the recombinant k 39 enzyme-linked immunosorbent assay to detect visceral leishmaniasis disease and infection in Bangladesh.

Several serology-based immunoassays are used to diagnose visceral leishmaniasis (VL), a chronic protozoan parasitic disease caused by the Leishmania donovani complex. These tests are primarily designed to diagnose the most severe clinical form of VL, known as kala-azar. However, leishmanial infection is frequently asymptomatic and may manifest only as a positive serologic response or positive leishmanin skin test. We modified a previously described enzyme-linked immunosorbent assay (ELISA) that detects patient antibodies reactive with the recombinant Leishmania protein K39 (rK39) to confirm suspected kala-azar and to detect asymptomatic infection in a community study in Bangladesh. With the inclusion of a standard curve on each ELISA plate, the rK39 ELISA was more repeatable (kappa coefficient of agreement=0.970) and more reliable compared to the original method (kappa=0.587, P<0.001). The cutoff point for a positive antibody response was chosen based on the 99th percentile of the ELISA distribution for the negative-control sera. However, we found that sera from all patients with active kala-azar yielded values more than twice the magnitude of this cutoff. Using receiver-operator characteristic curves, we determined a second cutoff value predictive of kala-azar. Using these criteria, the sensitivity and specificity of the modified ELISA for kala-azar were 97.0% and 98.9%, respectively, for sera from our study population. We hypothesize that individuals with antibody levels greater than the 99th percentile of the negative controls but less than the cutoff point for kala-azar have asymptomatic leishmanial infections.

Animals↗
PubMed2003

The pharmacokinetics of Simplex-tobramycin bone cement.

We prospectively investigated a consecutive series of ten patients undergoing a cemented primary total hip replacement (THR) for osteoarthritis in order to establish the elution characteristics of Simplex-tobramycin bone cement (Howmedica, Limerick, Ireland). Specimens of blood, urine and drainage fluid were collected for 72 hours postoperatively. Very high concentrations of tobramycin were found in the drainage fluid, with mean levels at one hour of 103 mg/l, which steadily declined to 15.1 mg/l after 48 hours. The mean serum tobramycin levels reached a peak of 0.94 mg/l at three hours and declined rapidly to 0.2 mg/l by 48 hours. The mean urinary tobramycin levels peaked at 57.8 mg/l at 12 hours with a rapid decline to 12.6 mg/l by 24 hours. There was a direct correlation between the amount of tobramycin bone cement which was implanted and the amount of tobramycin systemically absorbed. Excellent local delivery was achieved with minimal systemic concentrations. Simplex-tobramycin bone cement is an efficient and safe method for the delivery of antibiotics after THR.

Aged↗
PubMed2002

Dissociation between performance on abstract tests of executive function and problem solving in real-life-type situations in normal aging.

This study examined the effects of normal aging on real-life-type problem-solving performance, using problems that had previously been found to be sensitive to lesions involving the frontal lobes. Executive skills assessed on abstract neuropsychological tests tend to decrease with normal aging. The effects of aging on tasks reliant on everyday knowledge and experience are less well understood. In the present study, groups of healthy older and younger people were compared on ability to solve real-life-type problems covering a range of everyday interpersonal situations. Performance was also examined on a range of standardized neuropsychological tests involving executive skills. Older people were similar to younger people in most aspects of everyday problem-solving performance, although the older group appeared to use a different strategy to the younger group in generating potential problem solutions. Both groups performed normally for their age on the executive tests. Comparisons based on raw scores rather than age-adjusted scores showed the younger group to perform better on the executive tests, but not on the problem-solving task. The possible contribution of knowledge and experience to problem solving on the current task is discussed. The greater life experience of the older group is likely to be the biggest contributory factor in maintaining problem-solving performance.

Adult↗
PubMed2001

Factors associated with age at natural menopause in a multiethnic sample of midlife women.

An unprecedented number of women will experience menopause in the next decade. Although the timing of menopause affects long-term disease risk, little is known about factors that affect this timing. In the present 1995--1997 cross-sectional study, the Study of Women's Health Across the Nation, the relation of demographic and lifestyle factors to age at natural menopause was examined in seven US centers and five racial/ethnic groups. All characteristics were self-reported by women aged 40--55 years (n = 14,620). Cox proportional hazards models were used to estimate the probability of menopause by age. Overall, median age at natural menopause was 51.4 years, after adjustment for smoking, education, marital status, history of heart disease, parity, race/ethnicity, employment, and prior use of oral contraceptives. Current smoking, lower educational attainment, being separated/widowed/divorced, nonemployment, and history of heart disease were all independently associated with earlier natural menopause, while parity, prior use of oral contraceptives, and Japanese race/ethnicity were associated with later age at natural menopause. This sample is one of the largest and most diverse ever studied, and comprehensive statistical methods were used to assess factors associated with age at natural menopause. Thus, this study provides important insights into this determinant of long-term disease risk in women.

Adult↗
PubMed2001

Survival away from sheep and alternative methods of transmission of sheep lice (Bovicola ovis).

Transmission of sheep lice is thought to occur mainly by sheep to sheep contact although the possibility of other sources of infestation is often suggested. This study investigated the period of survival of Bovicola ovis after removal from sheep under varying conditions and assessed the likelihood of new infestations arising from contaminated facilities, wool caught on fences and shearers' footwear. In laboratory studies with lice held away from sheep at 4, 20, 25 and 36.5 degrees C, adults and nymphs survived longest at 25 degrees C (LT90 of 11.7 and 24.1 days for adults and large nymphs, respectively). Nymphs survived longer than adults and lice provided with raw wool survived longer than lice provided with wool that had been degreased. Nymphal lice survived for up to 29 days on unscoured wool at 36.5 degrees C, but the LT50 was less than 9 days in most experiments. In shearing sheds in winter and early spring lice survived for up to 14 and 16 days, respectively. These periods of survival are considerably longer than previously indicated for B. ovis. Most lice dropped out of wool staples attached to a fence within 1 h and only two of a total of 225 lice were still present after 24 h, suggesting that sheep are unlikely to become infested from wool caught on fences. Adult and nymphal lice readily transferred to shearers' moccasins and survived there for up to 10 days, indicating that transmission of lice on the footwear of shearers or other sheep handlers may be a cause of new infestations. Microwaving each moccasin for 5 min killed all lice and may provide a simple method of reducing the likelihood of transmission of B. ovis between properties.

Animal Husbandry↗
PubMed2001

Structural studies on gastroenteritis viruses.

There are many recent advances in our understanding of the structure-function relationships in rotavirus, a major pathogen of infantile gastroenteritis, and Norwalk virus, a causative agent of epidemic gastroenteritis in humans. Rotavirus is a large (1000 A) and complex icosahedral assembly formed by three concentric capsid layers that enclose the viral genome of 11 dsRNA segments. Because of its medical relevance, intriguing structural complexity, and several unique strategies in the morphogenesis and replication, this virus has been the subject of extensive biochemical, genetic and structural studies. Using a combination of electron cryomicroscopy and computer image processing together with atomic resolution X-ray structural information, we have been able to provide not only a better description of the rotavirus architecture, but also a better understanding of the structural basis of various biological functions such as trypsin-enhanced infectivity, virus assembly and the dynamic process of endogenous transcription. In contrast to rotavirus, Norwalk virus has a simple architecture with an icosahedral capsid made of 180 copies of a single protein. We have determined the structure of the Norwalk virus capsid to a resolution of 3.4 A using X-ray crystallographic techniques. These studies have provided valuable information on domain organization in the capsid protein, and residues that may be critical for dimerization, assembly, strain-specificity and antigenicity.

Capsid↗
PubMed2001

Survey of the use of intracranial pressure monitoring in children in the United Kingdom.

OBJECTIVE: To establish current practice for the monitoring and management of acute intracranial hypertension in children in United Kingdom intensive care units (ICUs). DESIGN: Postal questionnaire, targetted by prior telephone survey, to all ICUs admitting five or more children per annum with acute neurological illness. RESULTS: Of the units contacted 70 % responded, approximately one-half of which reported the use of intracranial pressure (ICP) monitoring. Only data from these units are presented. Nearly all of these units consider monitoring following serious head injury, but its use in non-traumatic brain injury is less widespread. The decision to institute ICP monitoring is based mainly upon neuroimaging appearances and Glasgow Coma Scale score. ICP and cerebral perfusion pressure targets differ markedly between centres, with only 46 % and 65 % of units, respectively, setting age-dependent parameters. Mannitol and varying degrees of hyperventilation are employed by all units to lower ICP. The majority also use barbiturates, diuretics, and fluid restriction. Controlled hypothermia is used in 52 % of units. Paediatric units are more likely to employ age-dependent cerebral perfusion pressure targets. Specific therapies employed to lower ICP are similar to those used in adult centres. CONCLUSION: Faced with a lack of both evidence and consensus, the management of acute intracranial hypertension in childhood varies widely. National or international guidelines for the management of children with raised intracranial pressure are needed. These should incorporate the physiological differences between children of different ages.

Adolescent↗
PubMed2001

Is there a menopausal syndrome? Menopausal status and symptoms across racial/ethnic groups.

In recent years, research on menopausal symptomalogy has focused on identifying symptom groupings experienced by women as they progress from premenopausal to postmenopausal status. However, most of these studies have been conducted among Caucasian women from western cultures. This leaves open the question of whether the findings from these studies can be extended to women of other racial/ethnic groups or cultures. Furthermore, many of the previous studies have been conducted on relatively small samples. This paper addresses the diversity of the menopause experience by comparing symptom reporting in a large cross-sectional survey of women aged 40-55 years among racial/ethnic groups of women in the United States (Caucasian, African-American, Chinese, Japanese, and Hispanic). Evaluation of the extent to which symptoms group together and consistently relate to menopausal status across these five samples provides evidence for or against a universal menopausal syndrome. The specific research questions addressed in this paper are: (1) How does the factor structure of symptoms among mid-aged women compare across racial/ethnic groups? (2) Is symptom reporting related to race/ethnicity or menopausal status? and (3) Does the relation between menopausal status and symptoms vary across racial/ethnic groups? Analyses are based on 14,906 women who participated in the multi-ethnic, multi-race, multi-site study of mid-aged women called the Study of Women's Health Across the Nation (SWAN). Study participants completed a 15-min telephone or in-person interview that contained questions on a variety of health-related topics. Items of interest for these analyses include symptoms, menstrual history (to assess menopausal status), health status, and sociodemographics. Factor analysis results showed that across all five racial/ethnic groups, two consistent factors emerged; one consisting of clearly menopausal symptoms -- hot flashes and night sweats -- and the other consisting of psychological and psychosomatic symptoms. Results of regression analyses showed racial/ethnic differences in symptom reporting, as well as differences by menopausal status. Controlling for age, education, health, and economic strain, Caucasian women reported significantly more psychosomatic symptoms than other racial/ethnic groups. African-American women reported significantly more vasomotor symptoms. Perimenopausal women, hormone users, and women who had a surgical menopause reported significantly more vasomotor symptoms. All of these groups, plus postmenopausal women, reported significantly more vasomotor symptoms than premenopausal women. The pattern of results argues against a universal menopausal syndrome consisting of a variety of vasomotor and psychological symptoms.

Black or African American↗
PubMed2001

Real-life-type problem-solving in Asperger's syndrome.

This study compared adolescents with Asperger's syndrome with typically developing adolescents on a novel problem-solving task that presented videotaped scenarios in real-life-type social contexts. The Asperger's group was impaired in several aspects of problem-solving, including recounting the pertinent facts, generating possible high-quality problem solutions, and selecting optimal and preferred solutions. This group's solutions differed most from those of the typically developing group in social appropriateness. The contributions of social experience, social understanding, and executive skills to performance on the novel problem-solving task are discussed.

Adolescent↗
PubMed2001

Body mass index in mid-life women: relative influence of menopause, hormone use, and ethnicity.

OBJECTIVE: To assess the relative influence of menopausal status and hormone use on body mass index (BMI) among a multiethnic sample of mid-life women. DESIGN: Cross-sectional telephone survey conducted at seven sites where each site targeted an ethnic minority group and Caucasians as part of Study of Women's Health Across the Nation (SWAN). SUBJECTS: A total of 7181 Caucasians, 3949 African-Americans, 1660 Hispanics, 562 Chinese Americans, and 803 Japanese Americans between ages of 40 and 55 y residing in or near Boston, Chicago, Detroit, Los Angeles, Newark, NJ, Oakland, CA, and Pittsburgh, PA. MEASUREMENTS: Self-reported BMI based on weight in kg divided by height in m(2) menopausal status, physical inactivity, postmenopausal hormone use, ethnicity, and age in years. RESULTS: Compared to premenopausal women (covariate adjusted M=27.3), women reporting a surgical menopause (M=28.2) or being in the perimenopausal transition (M=27.7 for early and 27.9 for late perimenopause) had higher BMI. Women reporting a natural menopause (M=27.4) did not have a higher BMI than premenopausal women, after adjusting for chronological age and other covariates. Hormone use was associated with lower BMI (M=26.5 vs 27.3). A comparison of effect sizes showed that menopausal status (F=13.1), followed by chronological age (F=24.0), were the least powerful predictors of BMI, whereas the more powerful predictors were physical activity level (F=1377.1) and ethnicity (F=400.5). CONCLUSIONS: The menopausal transition affects body mass index in mid-life, but the effect is small relative to other influences. Interventions to increase physical activity are highly recommended to prevent increases in adiposity common in mid-life.

Adult↗
PubMed2001

Covert fears and anxiety in asthma and congenital heart disease.

AIM: To compare anxiety, fears and behavioural problems in children with asthma and children with congenital heart disease, and with the normative population. To also review the influence of maternal anxiety, time since diagnosis and severity of disease. DESIGN: Children administered Fear Survey Scale (FSSC-R) and Child Manifest Anxiety Scale (R-CMAS). Mothers given Child Behaviour Checklist (CBCL) and State Trait Anxiety Scale (STAI-S and STAI-T). Normative means and SDs compared with means and SDs for both medical groups. The mother's scores on the STAI-S and STAI-T scales were correlated with the child's scores on the FSSC-R and the R-CMAS. SETTING: Outpatient Asthma and Cardiology multidisciplinary Clinics at a tertiary care paediatric facility, Alberta Children's Hospital. SUBJECTS: Forty children with asthma (aged 6--17 years) were compared with 39 children with congenital heart disease. Intake questionnaires and interviews determined these children to be without obvious psycho-social problems. RESULTS: Children with asthma and children with congenital heart disease had more medical fears, and more physiological anxiety than normative samples. Increased maternal anxiety was correlated in both groups with increased child anxiety, medical fears and behavioural problems in the child. Similarly, increased severity of asthma or cardiac problems was associated with more physiological anxiety and more fears. Less time since diagnosis of the disease adversely affected social interactions in both groups of children. CONCLUSION: Physiological anxiety, medical fears and maternal anxiety are important issues requiring attention in asthma and cardiac disease, even in the absence of obvious psychosocial problems. There may be specific problems with a recent diagnosis of a chronic illness.

Adult↗
PubMed2001

Brefeldin A affects adhesion of zoospores of the green alga Enteromorpha.

Primary adhesion of zoospores of the green macroalga Enteromorpha to substrata involves a massive release of adhesive glycoproteins from Golgi-derived, membrane-bounded vesicles in the anterior region of the spore, followed by rapid curing. This process is sensitive to low concentrations (5-10 microg x ml(-1)) of the secretion-inhibiting antibiotic, brefeldin A (BFA). The proportion of cells that settled in BFA was reduced by approximately 50%, but the effect was fully reversed by washing in seawater to remove the BFA. Ultrastructural observations showed that BFA caused the breakdown of Golgi stacks in the majority of cells examined. When settled cells were subjected to shear stress, a greater proportion of those settled in the presence of BFA were detached, compared with controls, indicating reduced adhesion strength in the presence of the antibiotic. The most likely reason for this is that strong adhesion to substrata either requires the synthesis of extra adhesive materials beyond those present in the swimming spore, or the secretion of an additional component required for adhesive curing. The novel use of atomic force microscopy in force modulation mode demonstrated that the adhesive secreted by most spores in the presence of BFA did not undergo the rapid curing process typical of control spores. However, some variation between zoospores was observed, with some cells showing no ultrastructural changes and normal adhesive curing. These results are discussed in relation to variations observed in the propensity and competence of spores to settle, which may be reflected in differential requirements for de novo synthesis and secretion of materials needed for full adhesion.

Antifungal Agents↗