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Biomedical subjects

G Anderson

Publications and source records attributed to G Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1999

Experimental transmission of Neisseria gonorrhoeae from pregnant rat to fetus.

Sprague-Dawley rats were infected on day 20 of pregnancy by intraperitoneal inoculation with Neisseria gonorrhoeae. Disseminated gonococcal infection (DGI) and pelvic inflammatory disease (PID) strains in the presence of C1q but not in the presence of bovine serum albumin (BSA) were able to spread from the pregnant rat to the fetus and resulted in fetal mortality. Transmission of DGI and PID strains that are serum resistant (ser(r)) and sac-4 positive but not of a local infection strain that is ser(s) and sac-4 negative was facilitated by the C1q-dependent mechanism. This study provides the first experimental model that may mimic the transmission of gonococcal infection from mother to the fetus during pregnancy.

Animals↗
PubMed1999

Non-adherence with ACE inhibitor treatment is common in heart failure and can be detected by routine serum ACE activity assays.

OBJECTIVE: To assess whether serum angiotensin converting enzyme (ACE) activity during routine clinical practice accurately reflects patient adherence to ACE inhibitor treatment for chronic heart failure (CHF). DESIGN: Retrospective assessment of ACE inhibitor adherence and serum ACE activity measurements. SETTING: Teaching hospital outpatient department PATIENTS AND INTERVENTIONS: During 1994-95, serum ACE was measured in 73 CHF patients who were routinely attending the heart failure clinic at Ninewells Hospital. At the same time, the medicines monitoring unit collected data on whether and when prescriptions for ACE inhibitors were redeemed at community pharmacies, which enabled each patient's adherence over a prolonged period to be assessed. MAIN OUTCOME MEASURES: Routine collected serum ACE measurements were correlated with measured adherence with ACE inhibitor treatment. RESULTS: In total, 18% of CHF patients appeared to exhibit < 70% adherence with their ACE inhibitor treatment with 34% exhibiting less than 85% adherence and 58% exhibiting < 100% adherence. A serum ACE activity of > 12 u/l gave 91% positive predictive accuracy that the patient was < 100% adherent with their ACE inhibitor treatment. At the other extreme, a serum ACE < 6.5 u/l gave 81% positive predictive accuracy that the patient was > 85% adherent with ACE inhibitor treatment. CONCLUSIONS: Non-adherence with ACE inhibitor treatment was found to be common in patients with CHF. The simple, inexpensive test of serum ACE activity can be used in CHF patients to identify many, although not all, non-adherent patients so that adherence enhancing strategies can be targeted towards them. Further work is clearly required to explore the precise clinical use of this promising test.

Aged↗
PubMed1999

Nondirectiveness in prenatal genetics: patients read between the lines.

For decades questionnaires have been used to measure the cognitive and psychological effects of prenatal genetic testing, but little is known about why some women undergo testing and others decline. Research indicates that many factors influence decision making, including values and beliefs. What is often denied rather than recognized is that the professional and personal values and beliefs held by the health care provider influence the patient's decision. It is assumed that, if genetic services are delivered in a nondirective manner, patients will not be affected by the provider's personal and professional standpoint. The qualitative research data reported here challenge this assumption. Getting to know patients' moral understanding and patterns of ethical reasoning by listening to their personal stories is recommended as a better way for nurses to help patients to make informed and autonomous decisions about prenatal genetic screening or diagnostic tests.

Adult↗
PubMed1999

Patient-perceived quality of life after coronary bypass surgery. Experienced problems and reactions to supportive care one year after the operation.

In an interview conducted one year after coronary bypass surgery (CABG), 115 patients (92 males, 23 females) were asked to discuss their present quality of life, problems related to the operation and their reactions to the supportive care following the operation. The main purpose of this study was to assess whether the patients' own presentation of these questions revealed information not elucidated through a standard questionnaire which included the Nottingham Health Profile and other questions on physical, emotional and social well-being. About one quarter of the interviewed patients expressed dissatisfaction concerning their present quality of life, information which corresponded well with the findings in the questionnaires. Reported limitation in physical activity did not, however, match exercise test findings. The interviews alone revealed additional information concerning well-being. Most important were problems with wound healing and difficulties describing and interpreting pain and other discomfort in the thoracic area. Several patients also expressed dissatisfaction with the postoperative supportive care. We conclude that there is a need for a complementary approach to estimate quality of life, and that this could be included in an extended nursing care program designed to meet the varying needs of patients after CABG.

Activities of Daily Living↗
PubMed1999

Add genetics to your knowledge base.

Genetics information will change how we think about our health, lead our lives, and treat many illnesses. For clinicians to initiate new treatments, we must have a clear, unified understanding of genetics and the ability to educate our patients.

Genetics, Medical↗
PubMed1998

Differential effects of peptide diversity and stromal cell type in positive and negative selection in the thymus.

Thymocyte positive selection results in maturation to the single-positive stage, while negative selection results in death by apoptosis. Although kinetic analyses indicate only 3-5% of CD4+ 8+ cells reach the single-positive stage, the balance of positive and negative selection and the nature and quantity of cells mediating maximal negative selection are uncertain. Here, using a system where the number and type of stromal cells and thymocytes can be controlled, we investigated the maturation of CD4+ 8+ thymocytes in the presence or absence of thymic epithelium and dendritic cells (DC) from wild-type (wt) and H-2M(-/-) mice expressing different peptide arrays. We find that titration of wt DC into reaggregates of wt epithelium has a dramatic effect on the number of CD4+ cells generated, with 1% DC causing a maximal 80% reduction. Moreover, while addition of 1% wt DC into cultures of H-2M(-/-) epithelium causes a 90% reduction in CD4+ cells, no effect was observed when similar numbers of wt thymic epithelium were added. Collectively, these data provide the first accurate indication of the quantity and quality of stromal cells required for maximal negative selection in the thymus, demonstrate the importance of peptide diversity in T cell selection, and highlight a large degree of overlap between positive and negative selection events.

Animals↗
PubMed1998

Capitation for cardiologists: accepting risk for coronary artery disease under managed care.

Patients with chronic disease may be excluded from capitated managed care plans due to higher than average expected costs. In an attempt to remedy this inequity, one type of risk adjustment technique proposes to set separate capitation rates for certain chronic illnesses, including coronary artery disease (CAD). Cardiologists, who increasingly are requested to accept capitation, will benefit from understanding the impact of using clinical factors as opposed to using demographic factors to set capitation rates. Using a 5% national random sample of the 1992 Medicare population, we determined mean annual expenditures and variation in expenditures of individuals with CAD. We compared the use of 2 demographic factors currently used for capitation rate adjustment (age and gender) with 2 factors not currently used--3-digit International Classification of Disease (ICD-9) code (a measure for severity) and Charlson index (a measure for comorbidity). Mean annual expenditures for individuals with CAD were more than double mean annual expenditures for the general Medicare population ($6,944 vs $3,247). Among individuals with CAD, mean expenditures of subgroups defined by both age and gender ranged from $6,205 to $7,724. In comparison, stratifying by measures of severity and comorbidity identified subgroups with lower and higher mean expenditures, producing a range of $1,702 to $19,959. Substantial variation of expenditures for individuals within subgroups defined by severity and comorbidity remained, with few patients having substantially higher expenditures than the rest. When capitation rates are set with the use of demographic factors alone, patients may be subjected to risk selection and physicians to financial loss. Using clinical measures may decrease the incentive for patient risk selection, but substantial financial risk to physicians would remain, because of a relatively few patients with high expenditures (or costs).

Aged↗
PubMed1998

Use of explant technology in the study of in vitro immune responses.

The establishment of in vitro culture systems provides an accessible means to study events within the immune system. In contrast to either dispersed suspension or two-dimensional monolayer culture, the explantation of tissue fragments under organ culture conditions is, to date, the only method which allows essential three-dimensional cellular interactions to be maintained under conditions which permit controlled experimental manipulation in vitro. Recent modifications of explant technology, particularly within the area of fetal thymic organ culture, now allow the controlled reassociation of defined cellular subsets and manipulation of gene expression, under conditions where the functioning of both lymphoid and stromal cell types closely resembles that in vivo.

Immunity↗
PubMed1998

Use of selective serotonin-reuptake inhibitors or tricyclic antidepressants and risk of hip fractures in elderly people.

BACKGROUND: Tricyclic antidepressants (TCAs) are associated with an increased risk of falls and hip fractures in elderly people. Selective serotonin-reuptake inhibitors (SSRIs) are reported to be better tolerated than TCAs. We investigated the risk of hip fractures associated with SSRIs and TCAs. METHODS: This case-control study used administrative healthcare data from the province of Ontario, Canada. 8239 cases-patients aged 66 years or older, treated in hospital between April, 1994, and March, 1995, for hip fracture-were each matched for age and sex to five controls. Logistic regression was used to calculate the odds ratio for hip fracture with adjustment for potential confounding effects produced by concomitant drug use and comorbidity. FINDINGS: With participants who had no exposure to antidepressants as the reference category, the adjusted odds ratio for hip fracture was 2.4 (95% CI 2.0-2.7) for exposure to SSRIs, 2.2 (1.8-2.8) for exposure to secondary-amine TCAs, and 1.5 (1.3-1.7) for exposure to tertiary-amine TCAs. For all types of antidepressants, current use was associated with a higher risk of hip fracture than former use. The odds ratios for hip fracture were higher for new current users than for continuous current users in all three drug classes. The proportion of current use in the low-dose range was 22% for SSRIs, 50% for secondary-amine TCAs, and 58% for tertiary-amine TCAs. INTERPRETATION: Exposure to any of the three classes of antidepressants is associated with a significant increase in the risk of hip fracture. Despite differences in dose distribution, this analysis suggests that SSRIs do not offer an advantage over TCAs in terms of risk of hip fracture.

Accidental Falls↗
PubMed1998

Identification of a developmentally regulated phase of postselection expansion driven by thymic epithelium.

To investigate events following the initiation of positive selection, we have used reaggregate organ cultures to follow the maturation of purified CD4+8+69+ thymocytes; these thymocytes represent a subpopulation of thymocytes which have already received positive selection signals. Using a dilution analysis of an FITC-based membrane-binding dye, 5-(and -6)-carboxyfluorescein diacetate succinimidyl ester, to allow a quantitative measure of proliferation, we show that while newly selected CD4+ and CD8+ cells are nondividing, both subsets subsequently undergo a wave of postpositive selection proliferation involving multiple cell divisions. Moreover, in the presence of fetal stromal cells, postselection expansion is more extensive in newborn thymocytes compared with adult thymocytes, suggesting that this phase of expansion is developmentally regulated. We also show that proliferation of CD4+ and CD8+ cells is seen in reaggregates of purified MHC class II+ thymic epithelial cells, while CD4+ and CD8+ cells generated from bcl-2 transgenic CD4+8+69+ thymocytes in the absence of stromal cell support survive but do not proliferate; this observation indicates that MHC class II+ thymic epithelial cells are both necessary and sufficient to mediate this wave of cell division. Finally, the maturation of CD4+8+69+ thymocytes and the subsequent proliferation of CD4+ and CD8+ cells occur in the presence of MHC-mismatched thymic stromal cells, suggesting that the later stages of positive selection and the associated postselection events do not depend on interactions with the same peptide/MHC complexes responsible for initiation.

Animals↗
PubMed1998

Emotional distress before coronary bypass grafting limits the benefits of surgery.

BACKGROUND: The inclusion of large, heterogeneous groups of patients for coronary bypass grafting (CABG) surgery has resulted in a more mixed treatment outcome. Thus it becomes important to identify patients who are less likely to benefit from surgery or who may require additional support to improve treatment outcome. The aim of the present study was to examine whether psychological status measured before CABG can contribute to prediction of short- and long-term outcomes of the surgery. METHODS AND RESULTS: One hundred seventy-one consecutive patients from two large university hospitals in Stockholm completed a psychosocial questionnaire before being scheduled for surgery. One year after CABG, patients again completed the questionnaire. Follow-up of medical charts was conducted during the first 3 years after surgery. All major cardiac events (cardiac death, definite myocardial infarction, revascularization, and unstable angina verified by angiography or myocardial scintigraphy) were recorded. Although the overall effect of surgery was excellent in the majority of cases, the patients exhibiting a high degree of distress (anxiety, depression, and tiredness) before surgery assessed their status as being much worse both before the operation and at the 1-year follow-up. Equally important was the fact that patients considered distressed before surgery had significantly higher rates of cardiac events (16%) in the 3-year follow-up period compared with nondistressed patients (5%) (chi-square=5.11, degrees of freedom=1, p < 0.02). CONCLUSIONS: Systematic evaluation and treatment of emotional distress in the candidates for coronary revascularization may be expected to result in more optimal subjective results and a reduction in the number of serious cardiac events after surgery.

Adult↗
PubMed1998

Determinants of outcome after carotid endarterectomy.

BACKGROUND: The efficacy of carotid endarterectomy for selected patients has been evaluated with randomized controlled clinical trials. The generalizability of these studies to average surgical practice remains an important public health concern. OBJECTIVE: The objective of the study was to determine the predictors of outcome after carotid endarterectomy on a regional basis. PATIENTS AND METHODS: The study was designed as a retrospective cohort study and included all consecutive patients presented for carotid endarterectomy at the 8 University of Toronto-affiliated hospitals in the period from January 1, 1994, to December 31, 1996. The main outcome measure was 30-day postoperative stroke or death rate. RESULTS: During the study interval, 1280 primary carotid endarterectomies were performed. The overall combined stroke and death rate was 6.3% for all patients who underwent endarterectomy (4.0% for patients who were asymptomatic). The significant predictors of poor outcome were the following: presenting symptoms (odds ratio, 1.74; 95% confidence interval [CI], 0.96, 3.12), low surgeon volume (<6 cases per year; odds ratio, 3.98; 95% CI, 1.65, 9.58), and left-sided surgery (odds ratio, 1.72; 95% CI, 1.07, 2.76). CONCLUSION: These data suggest that adoption of the recommendations of the symptomatic carotid endarterectomy trials is appropriate. However, endarterectomy for asymptomatic lesions remains of uncertain benefit on a regional basis and must be individualized to the experience of the specific surgeon. The surgeon volume/outcome relationship that is identified in this study suggests a need for a minimum volume threshold for this procedure.

Adult↗
PubMed1998

Low-dose intermittent factor replacement for post-operative haemostasis in haemophilia.

Recommendations for factor replacement therapy for postoperative haemostasis in haemophilia are often empirical and based on the physiological understanding of haemostatic requirements. This report describes the haemostatic management of patients with severe haemophilia undergoing major surgery using lower than usually recommended levels of factor replacement therapy. Eighteen adults (11 with FVIII and seven with FIX deficiency) with an average weight of 52 kg (range: 27-69) underwent 20 major surgical procedures. Factor concentrates were administered by intermittent bolus infusions. The dose of FVIII infused before surgery was 76 mu kg-1 (range: 51-113) and that of FIX was 77 mu kg-1 (range: 50-104). The preoperative levels achieved were 107% (range: 80-180) and 73% (range: 60-90), respectively. Between days 1 and 3 after surgery, an average of 29 mu kg-1 day-1 (range: 20-46) of FVIII and 23 mu kg-1 day-1 (range: 12-42) of FIX was used resulting in mean trough levels of 36% (range: 12-62) and 34% (range: 11-52), respectively. After day 4, an average of 19 mu kg-1 day-1 (range: 15-25) of FVIII and 18 mu kg-1 day-1 (range: 10-37) of FIX was administered until wound healing. The average duration of factor replacement was 11 days (range: 8-16). The mean dose of factor concentrate per patient was 260 mu kg-1 (range: 179-338) of FVIII and 300 mu kg-1 (range: 183-524) of FIX. The total amount of factor used per patient ranged from 12,380 to 19,980 units of FVIII and 8000 to 23,600 units of FIX. Only one patient had post-operative bleeding which was due to a surgical cause. It is concluded that it may be possible to use much lower than recommended levels of factor replacement therapy for postoperative haemostasis in severe haemophilia.

Adolescent↗