Biomedical subjects

John O'Connor

Publications and source records attributed to John O'Connor.

16 recordsLinked to original sources

PubMed2006

Role of radiation therapy in gastric adenocarcinoma.

Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.

Adenocarcinoma↗

PubMed2006

Aquatics, health-promoting self-care behaviours and adults with brain injuries.

PRIMARY OBJECTIVE: To determine the effect of an aquatic programme on the health promoting behaviours of adults with brain injuries. MAIN OUTCOMES AND RESULTS: Eighteen individuals participated in the programme and were randomly assigned to an experimental (n = 9) or control group (n = 9). Health promoting behaviours, physical self-concept and self-esteem were measured pre- and post-intervention. Significant differences and large effect sizes were found between scores for the experimental group only, indicating an increase in health promoting behaviours, physical self-concept and self-esteem. CONCLUSIONS: Results have useful implications for health professionals as exercise prescription may enhance health promoting behaviours and decrease health care costs after a brain injury.

Adult↗

PubMed2005

Role of the estrogen and progestin in hormonal replacement therapy on apolipoprotein A-I kinetics in postmenopausal women.

OBJECTIVE: Plasma high-density lipoprotein (HDL) cholesterol levels are inversely correlated with the risk of developing coronary heart disease. Hormonal replacement therapy (HRT) affects plasma HDL cholesterol levels, with estrogen increasing HDL cholesterol levels and progestins blunting this effect. This study was designed to assess the mechanism responsible for these effects. MATERIALS AND METHODS: HDL apolipoprotein A-I (apoA-I) kinetics were studied in 8 healthy postmenopausal women participating in a double-blind, randomized, crossover study comprising 3 phases: placebo, conjugated equine estrogen (CEE) (0.625 mg/d), and CEE plus medroxyprogesterone acetate (MPA) (2.5 mg/d). Compared with placebo, treatment with CEE resulted in an increase in apoA-I pool size (+20%, P<0.01) because of a significant increase in apoA-I production rate (+47%, P<0.05) and no significant changes in apoA-I fractional catabolic rate. Compared with the CEE alone phase, treatment with the CEE plus MPA resulted in an 8% (P<0.02) reduction in apoA-I pool size and a significant reduction in apoA-I production rate (-13%, P<0.04), without changes in apoA-I fractional catabolic rate. CONCLUSIONS: Postmenopausal estrogen replacement increases apoA-I levels and production rate. When progestin is added to estrogen, it opposes these effects by reducing the production of apoA-I.

Apolipoprotein A-I↗

PubMed2004

Myocardial injury, neurohormonal activation and inflammation after internal atrial defibrillation.

BACKGROUND: The effects of patient-activated atrial defibrillation on subclinical myocardial injury are unknown. Using biochemical markers, this study assessed the effect of a single internal atrial shock delivered by the implantable atrial defibrillator on myocardial damage, neurohormonal activation and inflammation. METHODS: Twelve patients were implanted with a dual chamber defibrillator for the sole indication of drug refractory symptomatic persistent atrial fibrillation (AF). All had maximum defibrillation energy programmed to maximise the first shock success rate. Creatine kinase isoenzyme, troponin T, cortisol, catecholamines, C-reactive protein and brain natriuretic peptide were measured (i) during sinus rhythm, (ii) 8 h after onset of spontaneously occurring AF (before cardioversion) and (iii) 8 h following successful patient activated cardioversion. RESULTS: There was no change in creatine kinase, troponin T, cortisol or C-reactive protein during AF or following internal cardioversion. Brain natriuretic peptide levels rose from a median value of 56 pg/ml during sinus rhythm (inter-quartile range 14-92 pg/ml) to 133 pg/ml during AF (30-262 pg/ml), p=0.002. There was a decrease 8 h after cardioversion to baseline (52 and 40-189 pg/ml), p=0.01. There were increases in serum adrenaline and noradrenaline levels during AF from 0.43 (0.12-0.61) to 0.58 pg/ml (0.39-0.80 pg/ml), p=0.002 and from 2.06 (1.61-2.59) to 2.83 nmol/l (2.43-3.46 nmol/l), p=0.02, respectively. These figures reverted to baseline levels 8 h post-cardioversion. CONCLUSIONS: Internal atrial defibrillation does not result in myocardial injury. The onset of AF results in sympathetic activation and increased brain natriuretic peptide levels, which resolve following restoration of sinus rhythm.

Adult↗

PubMed2004

Paternal smoking and pregnancy loss: a prospective study using a biomarker of pregnancy.

Results of studies on paternal smoking and spontaneous abortions have been inconsistent. The authors examined the effect of paternal smoking on the risk of pregnancy loss in a prospective cohort of 526 newly married, nonsmoking, female textile workers in China between 1996 and 1998. Upon stopping contraception, subjects provided daily urine specimens and records of vaginal bleeding for up to 1 year or until clinical pregnancy. Daily urinary human chorionic gonadotropin was assayed to detect conception and early pregnancy losses, and pregnancies were followed to detect clinical spontaneous abortions. Subjects were grouped by the number of cigarettes that husbands reported smoking daily: nonsmokers (group 1, n = 216), fewer than 20 cigarettes (group 2, n = 239), and 20 or more cigarettes (group 3, n = 71). Compared with that for group 1, the adjusted odds ratio of early pregnancy loss of any conception for group 2 was 1.04 (95% confidence interval (CI): 0.67, 1.63) and for group 3 was 1.81 (95% CI: 1.00, 3.29). The adjusted hazard ratio of conception for group 2 was 0.90 (95% CI: 0.70, 1.18) and for group 3 was 0.96 (95% CI: 0.66, 1.39), while the adjusted hazard ratio of clinical pregnancy for group 2 was 0.93 (95% CI: 0.72, 1.20) and for group 3 was 0.78 (95% CI: 0.55, 1.12). The authors conclude that heavy paternal smoking increased the risk of early pregnancy loss through maternal and/or paternal exposure.

Abortion, Spontaneous↗

PubMed2004

Information management and informatics: need for a modern pathology service.

Requirements for information technology in pathology now extend well beyond the provision of purely analytical data. With the aim of achieving seamless integration of laboratory data into the total clinical pathway, "informatics"--the art and science of turning data into useful information--is becoming increasingly important in laboratory medicine. Informatics is a powerful tool in pathology--whether in implementing processes for pathology modernization, introducing new diagnostic modalities (e.g. proteomics, genomics), providing timely and evidence-based disease management, or enabling best use of limited and often costly resources. Providing appropriate information to empowered and interested patients--which requires critical assessment of the ever-increasing volume of information available--can also benefit greatly from appropriate use of informatics. General trends in medical informatics are reflected in current priorities for laboratory medicine, including the need for unified electronic records, computerized order entry, data security and recovery, and audit. The increasing demands placed on pathology information systems in the context of wider developmental change in healthcare delivery are explored in this paper.

Data Collection↗

PubMed2003

Definition and measurement of chasing in off-course betting and gaming machine play.

The attempt to recover gambling losses by continuing to gamble ('chasing') has featured prominently in accounts of excessive gambling. This research represents the first attempt to operationalize and measure chasing in terms of its cognitive (behavioral intention), emotive (urges) and behavioral components, and to investigate the role of chasing in relation to impaired control over gambling. Two survey samples of 84 male off-course (betting shop) race gamblers (mean age 41, SD = 15) and 137 gaming machine players (73 females, mean age 48, SD = 15 and 64 males, mean age 43, SD = 16) were recruited at gambling venues. Respondents completed a structured questionnaire that investigated retrospective report of chasing and an impaired control scale ("The Scale of Gambling Choices"). It was found that the various components of chasing formed a composite measure with high internal reliability that was strongly related to indicators of excessive gambling (e.g. time spent gambling, expenditure as a proportion of income) and to impaired control scores. Reacting to large wins by further betting was almost as strongly related to impaired control as was persistence after losing. Those who returned later to chase had significantly higher impaired control scores than those who only chased within a session. Alcohol-related chasing was associated with impaired control over gambling. Chasing of losses and impaired control appear to be generic processes in evidence across both forms of gambling and gender (most format and sex differences were of minor significance).

Adult↗

PubMed2003

Impaired control over gambling in gaming machine and off-course gamblers.

AIM: To investigate and compare subjectively reported impaired control in two forms of gambling: off-course Totalizator Agency Board (TAB) horse/dog racing and electronic gaming machines (EGMs). Additionally, gender differences in EGM play were investigated. DESIGN: A survey sample of 84 male TAB gamblers and 137 EGM players (73 females and 64 males) was recruited at gambling sites. SETTING: Hotels and clubs in Adelaide, South Australia, were used as recruiting venues. Interviews were either conducted on site if there was sufficient privacy, or relocated to nearby cafes. PARTICIPANTS: The inclusion criteria were gambling at least weekly and being over the age of 18. Female off-course gamblers were not approached given their scarcity. MEASUREMENTS: A general gambling involvement questionnaire was devised from pilot research. Impaired control was measured using a shortened version of The Scale of Gambling Choices. FINDINGS: Impaired control over gambling has a robust factor structure, with little difference between EGM and TAB gamblers. Concurrent validity for the impaired control measure was demonstrated against measures of gambling involvement. CONCLUSION: Impaired control appears to be, in the main, a generic process across these two forms of gambling and for both sexes. Further refinement and application of the concept of impaired control to excessive gambling seems warranted given its strong face, construct and concurrent validity.

Adult↗

PubMed2002

Relationship of phospholipid transfer protein activity to HDL and apolipoprotein B-containing lipoproteins in subjects with and without type 1 diabetes.

Patients with type 1 diabetes have greatly increased phospholipid transfer protein (PLTP) activity and have an altered HDL subclass distribution. In 195 patients with type 1 diabetes and in 194 men and women aged 30-55 years, we examined the relationship of PLTP activity to HDL and examined whether PLTP activity contributes to differences in HDL found in type 1 diabetes. PLTP activity was measured using an exogenous substrate assay. Average HDL particle size and HDL subclasses were measured using nuclear magnetic resonance spectroscopy. Apolipoprotein AI (apoAI) and apoAII were measured by immunoturbidimetry. The amount of apoAI present in LpAI was measured using a differential electroimmunoassay, and the amount of apoAI in LpAIAII was inferred from the apoAI and LpAI data. Higher PLTP activity was associated with more large HDL (P < 0.001) and less small HDL (P < 0.01), more apoAI and apoAII (both at P < 0.001), and more apoAI in both LpAI and LpAIAII (P = 0.02 and P < 0.001, respectively). These associations were independent of other lipids and enzyme activities. Adjusting for PLTP activity halved the difference between subjects with and without diabetes in apoA1 (from 10.1 mg/dl higher in subjects with diabetes to 4.6 mg/dl higher) and large HDL (2.4 micro mol/l higher to 1.2 micro mol/l higher) and reduced the difference in HDL size (from 0.31 nm higher to 0.26 nm higher). PLTP activity was also positively associated with apoB, total VLDL and LDL particle number, and IDL level in subjects with diabetes. These data support the idea that PLTP is a major factor in HDL conversion and remodeling in humans and that higher PLTP activity makes an important contribution to the higher apoAI levels and altered HDL subclass distribution in type 1 diabetes. They also support a role for PLTP in the metabolism of apoB-containing lipoproteins.

Adult↗

PubMed2002