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Biomedical subjects

L Bacon

Publications and source records attributed to L Bacon.

At least 19 recordsLinked to original sources
PubMed2004

Low bone mass in premenopausal chronic dieting obese women.

BACKGROUND: Obese premenopausal women are thought to be at low risk for osteoporosis due to increased body weight and effects of estrogen on weight-bearing bone. OBJECTIVE: To examine the effect of restrained eating on obese women, we examined bone mineral density (BMD) and content (BMC) of the spine and femur in obese women who were restrained eaters, with emphasis on the relationship between BMC and determinants of bone mass, and current eating behaviors, dietary intake, physical activity, and indices of calcium regulation, bone metabolism, stress and inflammation. DESIGN: A total of 78 obese, Caucasian, female, restrained eaters, ages 30-45 y, were enrolled in a weight lose program. Height, weight, bone turnover markers, serum parathyroid hormone (PTH), cortisol, c-reactive protein (CRP), dietary intake, eating behaviors, physical activity, and BMD and BMC were measured. SETTING: This study was conducted at the University of California, in Davis, CA, USA. RESULTS: In all, 31% of women had osteopenia or osteoporosis (OSTEO). In the OSTEO group, 87.5% of women had osteoporosis or osteopenia of the lumbar spine and 12.5% of the women had osteoporosis or osteopenia in femur. A significant positive correlation between BMC and energy expenditure (r=0.256), and a significant negative correlation between BMC and number of times on a weight loss diet (r=-0.250) and cognitive restraint (r=-0.239) were observed. No significant differences were observed between OSTEO women and nonosteoporotic women for current eating behaviors, dietary intake, physical activity habits, bone turnover, calcium regulation, stress, or inflammation. CONCLUSIONS: Obese restrained eaters are at risk for low bone mass. Prior dieting may be responsible. Chronic dieters should be encouraged to decrease their dietary restraint, develop healthy eating habits and increase physical activity.

Adult↗
PubMed2004

Managing genital infection in community family planning clinics: an alternative approach to holistic sexual health service provision.

OBJECTIVE: To pilot and evaluate sexually transmitted infection (STI) management in community family planning clinics (FPCs). METHODS: Number of STI tests taken, positive results, infections treated, contacts traced/treated, referrals to specialist services and time from testing to treatment were documented as well as age and sex of the population tested. RESULTS: STI tests taken increased from 233 to 308/month and male clients seen increased from 114 to 147/month across all clinics. Chlamydia prevalence rates in one large clinic increased from 6.7% to 11.9%. 82% of those with STIs in this clinic were treated. Of 44 clients treated for chlamydia, 84% had partner notification performed, 0.43 contacts were treated for every client with chlamydia and referrals to specialist services decreased. 70% of STIs were detected in clinic users under the age of 25 and 45.5% of clients tested under the age of 16 had an STI. Before STI treatment was available at FP clinics 52% of clients with STIs attended specialist services after referral and time from testing to treatment was 19 days. Managing STIs in the community increased treatment rates to 82% with a testing to treatment time of 10 days. CONCLUSIONS: The management of uncomplicated genital infection in community FPCs working in partnership with specialist services is a feasible and effective approach to holistic sexual health service provision.

Adult↗
PubMed2002

Evaluating a 'non-diet' wellness intervention for improvement of metabolic fitness, psychological well-being and eating and activity behaviors.

CONTEXT: Current public health policy recommends weight loss for obese individuals, and encourages energy-restricted diets. Others advocate an alternative, 'non-diet' approach which emphasizes eating in response to physiological cues (eg hunger and satiety) and enhancing body acceptance. OBJECTIVE: To evaluate the effects of a 'health-centered' non-diet wellness program, and to compare this program to a traditional 'weight loss-centered' diet program. DESIGN: Six-month, randomized clinical trial. SETTING: Free-living, general community. PARTICIPANTS: Obese, Caucasian, female, chronic dieters, ages 30-45 y (n=78). INTERVENTIONS: Six months of weekly group intervention in a non-diet wellness program or a traditional diet program, followed by 6 months of monthly after-care group support. OUTCOME MEASURES: Anthropometry (weight, body mass index); metabolic fitness (blood pressure, blood lipids); energy expenditure; eating behavior (restraint, eating disorder pathology); psychology (self-esteem, depression, body image); attrition and attendance; and participant evaluations of treatment helpfulness. Measures obtained at baseline, 3 months, 6 months and 1 y. RESULTS: (1 y after program initiation): Cognitive restraint increased in the diet group and decreased in the non-diet group. Both groups demonstrated significant improvement in many metabolic fitness, psychological and eating behavior variables. There was high attrition in the diet group (41%), compared to 8% in the non-diet group. Weight significantly decreased in the diet group (5.9+/-6.3 kg) while there was no significant change in the non-diet group (-0.1+/-4.8 kg). CONCLUSIONS: Over a 1 y period, a diet approach results in weight loss for those who complete the intervention, while a non-diet approach does not. However, a non-diet approach can produce similar improvements in metabolic fitness, psychology and eating behavior, while at the same time effectively minimizing the attrition common in diet programs.

Adult↗
PubMed1999

A fully human antibody neutralising biologically active human TGFbeta2 for use in therapy.

Phage display provides a methodology for obtaining fully human antibodies directed against human transforming growth factor-beta (TGFbeta) suitable for the treatment of fibrotic disorders. The strategy employed was to isolate a human single chain Fv (scFv) fragment that neutralises human TGFbeta2 from a phage display repertoire, convert it into a human IgG4 and then determine its TGFbeta binding and neutralisation properties and its physical characteristics. Several scFv fragments binding to TGFbeta2 were isolated by panning of an antibody phage display repertoire, and subsequent chain shuffling of the selected V(H) domains with a library of V(L) domains. The three most potent neutralising antibodies were chosen for conversion to IgG4 format. The IgG4 antibodies were ranked for their ability to neutralise TGFbeta2 and the most potent, 6B1 IgG4, was chosen for further characterisation. 6B1 IgG4 has a high affinity for TGFbeta2 with a dissociation constant of 0.89 nM as determined using the BIAcore biosensor and only 9% cross-reactivity with TGFbeta3 (dissociation constant, 10 nM). There was no detectable binding to TGFbeta1. 6B1 IgG4 strongly neutralises (IC50 = 2 nM) the anti-proliferative effect of TGFbeta2 in bioassays using TF1 human erythroleukaemia cells. Similarly, there was strong inhibition of binding of TGFbeta2 to cell surface receptors in a radioreceptor assay using A549 cells. 6B1 IgG4 shows no detectable cross-reactivity with related or unrelated antigens by immunocytochemistry or ELISA. The 6B1 V(L) domain has entirely germline framework regions and the V(H) domain has only three non-germline framework amino acids. This, together with its fully human nature, should minimise any potential immunogenicity of 6B1 IgG4 when used in therapy of fibrotic diseases mediated by TGFbeta2.

Amino Acid Sequence↗
PubMed1999

Evaluating a test protocol for predicting maximum lactate steady state.

BACKGROUND: Maximum lactate steady state (MLSS) is defined as the highest steady state exercise level one can maintain while also maintaining an equilibrium between the elimination of blood lactate and the diffusion of lactate into the blood. MLSS is an excellent tool for assessing fitness level, predicting endurance performance, and designing training programs. METHODS: This investigation assesses the validity of the Lactate Minimum Test (LMT), which consists of inducing lactic acidosis through a VO2peak test, followed by an eight-minute walking recovery and an incremental exercise test, to determine if the running velocity associated with the minimum lactate value predicts the MLSS velocity. Following this LMT, two constant velocity 28-minute runs were performed, one at the predicted MLSS velocity (trial 1) and the other 0.13 m sec-1 (4-8%) above the predicted MLSS velocity (trial 2). Ten active female subjects participated (32 +/- 7 yrs (mean +/- SD); 65.7 +/- 16.4 kg; VO2peak 40.0 +/- 7.5 ml.kg-1.min-1). RESULTS: During trial 1, there was a -0.6 +/- 0.3 mmol l-1 (mean +/- SE) change in lactate. Based on a definition of lactate steady state (LSS) as less than a 0.5 mmol.l-1 increase, this value signified LSS. A similar comparison during trial 2 revealed a 1.8 +/- 0.3 mmol.l-1 increase in lactate, signifying a workload above LSS and therefore confirming trial 1 as the maximum LSS (MLSS). CONCLUSIONS: These results suggest that the test protocol accurately predicted the MLSS velocity.

Adult↗
PubMed1998

Antigen specificity and tumour targeting efficiency of a human carcinoembryonic antigen-specific scFv and affinity-matured derivatives.

We have examined the biological properties of CEA6, a human carcinoembryonic antigen (CEA)-specific single-chain Fv (scFv) isolated by phage display, and five related clones derived by affinity maturation and selected for improved off-rate (Koff). All clones bind strongly and specifically to CEA-positive human tumours by immunocytochemistry and show negligible cross-reactivity with normal colon. Flow cytometry of scFv on human liver cells indicates a shift in fine epitope specificity resulting from mutagenesis. All monomeric scFv have been radioiodinated, retaining effectively full binding activity. A single intravenous injection into nude mice bearing human colon tumour xenografts confirms tumour targeting in all cases. As reported in other studies, the kidney is the main route of elimination of scFv at early time points. Tumour binding of the parental antibody CEA6 consistently gives the highest tumour-blood ratios at 24 h (mean 16:1). Clone TO6D11, which has a sevenfold reduced Koff relative to CEA6, showed no difference in tumour uptake at 24 h but persisted at the tumour site for longer than CEA6. This study demonstrates a possible correlation between binding affinity and tumour residence time when examined in this model.

Animals↗
PubMed1994

Age modulates the long-term but not the acute effects of the serotonergic neurotoxicant 3,4-methylenedioxymethamphetamine.

Tissue levels of serotonin (5-HT), levels of its metabolite 5-hydroxyindoleacetic acid (5-HIAA) and populations of 5-HT reuptake sites were measured in the brains of rats exposed to 3,4-methylenedioxymethamphetamine (MDMA) at selected developmental ages. MDMA exposure at postnatal day (PND) 10 did not result in altered 5-HT or 5-HIAA levels 1 week after administration in any brain region examined. However, MDMA exposure at PND 40 and PND 70 resulted in dose-dependent reductions in 5-HT and 5-HIAA levels at 1 week in all brain regions examined. Time course studies revealed that at PND 10, MDMA acutely (< or = 24 hr) reduced 5-HT levels and that these levels later recovered to control levels. MDMA also acutely reduced 5-HT levels at PND 40 and PND 70, but at these ages the 5-HT levels were persistently depressed ( > or = 72 hr). Time course studies also revealed that MDMA acutely elevated dopamine levels in caudate putamen at PND 40 and PND 70, but no alterations in dopamine levels were observed at PND 10. Analysis of 5-HT reuptake site populations revealed that at PND 10 and PND 40, MDMA had little effect on reuptake site populations. At PND 70, however, MDMA reduced 5-HT reuptake site populations as early as 24 hr after administration. These experiments demonstrate not only that the biochemical effects of MDMA exposure are altered by the developmental status of the experimental animal, but also that each individual biochemical component may show differing sensitivities to alteration by MDMA at different developmental ages.

Age Factors↗
PubMed1980

Use of indium-111 in antibody-dependent complement-mediated cytotoxicity assay for detection of B locus alloantigens on chicken lymphocytes.

An antibody-dependent complement-mediated cytotoxicity assay has been devised to detect B locus alloantigens on the surface of peripheral blood lymphocytes. The assay utilizes unheated chicken antiserum and guinea pig complement, which cooperate to yield specific lysis of 111In-labeled target cells. Specific cell lysis appears to be mediated by the classical complement pathway and can be inhibited by heat inactivation of the guinea pig complement. Heat inactivation of the chicken antiserum results in partial inhibition of cell lysis which can be restored by the addition of a small amount of unheated normal chicken serum. The use of a 111In-oxine chelate was found to be a quick and efficient way to label chicken cells. It has a high labeling efficiency, localizes primarily in the cytoplasm, and is released specifically from dead cells in a form that cannot be reutilized. The highly sensitive detection of B locus alloantigens with this assay strongly suggest that it will be of equal value in the detection of other alloantigens, tumor-specific (transplantation) antigens, and differentiation antigens on the surface of chicken cells.

Animals↗
PubMed1980

A review of two safety factors in the use of paraldehyde.

Clinical observations and laboratory tests suggest that, contrary to normal practice, paraldehyde can be used with certain plastic syringes and has been safely used when well over six months old. This may make its use as an anticonvulsant in primary care more widely acceptable.

Child↗