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Biomedical subjects

A Dawson

Publications and source records attributed to A Dawson.

At least 19 recordsLinked to original sources
PubMed2006

IGF-I and epidermal growth factor levels in follicular fluid of women undergoing controlled ovarian hyperstimulation using the multidose GnRH-antagonist protocol or the long GnRH-agonist protocol.

The intrafollicular levels of IGF-I and epidermal growth factor (EGF) were studied in women undergoing controlled ovarian hyperstimulation using the multidose GnRH-antagonist protocol or the long agonist protocol, in an attempt to elucidate whether GnRH-antagonists affect the levels of the two growth factors. The follicular fluid concentration of IGF-I, EGF, estradiol and progesterone were detected in 68 women undergoing ovarian hyperstimulation for intracytoplasmic sperm injection (ICSI) cycles. There were no differences in intrafollicular concentrations of EGF and IGF-I in the two studied groups. Additionally, we found no correlation between the intrafollicular levels of IGF-I or EGF and the ICSI outcome. The intrafollicular levels of IGF-I were positively correlated with those of progesterone. In conclusion, the intrafollicular levels of IGF-I and EGF do not seem to be influenced by the stimulation protocol. The intrafollicular levels of both growth factors can not serve as prognostic markers for the ICSI outcome.

Adult↗
PubMed2006

Screening oocytes by polar body biopsy.

Preimplantation genetic aneuploidy screening performed by polar body biopsy has become a frequently used method, especially as in several countries only preconceptional genetic diagnosis is allowed. To penetrate the zona pellucida, mechanical, chemical and laser-assisted techniques have been introduced. In this paper, the advantages, disadvantages, efficacy and safety of these techniques are elucidated.

Aneuploidy↗
PubMed2006

In defence of moral imperialism: four equal and universal prima facie principles.

Raanan Gillon is a noted defender of the four principles approach to healthcare ethics. His general position has always been that these principles are to be considered to be both universal and prima facie in nature. In recent work, however, he has made two claims that seem to present difficulties for this view. His first claim is that one of these four principles, respect for autonomy, has a special position in relation to the others: he holds that it is first among equals. We argue that this claim makes little sense if the principles are to retain their prima facie nature. His second claim is that cultural variation can play an independent normative role in the construction of our moral judgments. This, he argues, enables us to occupy a middle ground between what he sees as the twin pitfalls of moral relativism and (what he calls) moral imperialism. We argue that there is no such middle ground, and while Gillon ultimately seems committed to relativism, it is some form of moral imperialism (in the form of moral objectivism) that will provide the only satisfactory construal of the four principles as prima facie universal moral principles.

Beneficence↗
PubMed2006

Mass public health programmes and the obligations of sponsoring and participating organisations.

The obligations of organisations associated with policy formation and implementation of international mass public health programmes are explored. Lines of responsibility are considered to become unclear because of the large number of agencies associated with such programmes. A separation of the relevant obligations among the bodies responsible for the formulation (usually an international non-governmental organisation) and those responsible for the implementation of the policies (usually national bodies) is suggested. The continuing oral polio vaccine campaign against poliomyelitis in India is used to illustrate the general argument. Although the aim of the programme is legitimate and laudable, unnecessary harm is currently being caused to some children as a result of elements of the policy and this should be rectified immediately. Such mass programmes should take care to ensure that people are not unnecessarily sacrificed in the drive to attain the desirable ends of the policy.

Cost-Benefit Analysis↗
PubMed2005

The epidemiology of left ventricular hypertrophy in type 2 diabetes mellitus.

AIMS/HYPOTHESIS: Patients with type 2 diabetes mellitus are at greater cardiovascular risk than the general population. Although it is widely acknowledged that diabetes is a risk factor for coronary artery disease, the increased prevalence of potentially lethal left ventricular abnormalities in this population is less well appreciated. METHODS: We carried out an echocardiographic study of 500 subjects with type 2 diabetes mellitus to assess the prevalence of left ventricular hypertrophy (LVH) and left ventricular systolic dysfunction (LVSD). We also assessed whether abnormalities in diastolic filling parameters were present. RESULTS: Of the 371 patients in whom left ventricular mass could be successfully assessed, 264 had LVH (71%). Left ventricular systolic dysfunction was much less common, being present in 16/385 patients (4.2%). Long axis contraction was abnormal in 29/429 patients (6.8%). Diastolic filling abnormalities were present in 178/435 (41%) of patients who could be classified using the selected criteria. CONCLUSIONS: We conclude that left ventricular abnormalities are common in type 2 diabetic patients. As medical therapy is available for both LVH and LVSD and has been demonstrated to reduce cardiovascular death, these left ventricular abnormalities could be ideal targets for screening, followed by selective therapeutic intervention.

Aged↗
PubMed2005

Does routine intraoperative cholangiography prevent bile duct transection?

BACKGROUND: The role of routine intraoperative cholangiography is controversial. The aim of this study was to assess the impact of routine intraoperative cholangiography on the incidence of common bile duct injuries, and to evaluate the operative outcome of laparoscopic cholecystectomy carried out in a major teaching hospital and review the literature. METHODS: Prospectively collected data on 3,145 laparoscopic cholecystectomies performed mainly by surgical trainees in the period 1990 to 2002 using routine intraoperative cholangiography with fluoroscopy were reviewed. RESULTS: The mean age of the study sample (65.6% male, 34.4% female) was 54 years, and 16.9% of the patients had clinical acute cholecystitis. The conversion rate to open cholecystectomy was 4.3%. Intraoperative cholangiography was attempted for 90.7% of the patients with a 95.9% success rate. Five patients (0.16%) had common bile duct injuries. Four injuries had occurred in the first 5 years. One injury (0.06%) had occurred after 1995. This injury was identified intraoperatively and repaired laparoscopically. Routine intraoperative cholangiography prevented one definite common bile duct transection. CONCLUSIONS: In this series using routine intraoperative cholangiography, there was a low rate and severity of common bile duct injuries, with a high intraoperative recognition rate. There was no bile duct transection or major injury requiring common bile duct reconstruction. Although intraoperative cholangiography helped in the immediate identification of injuries and the institution of appropriate therapy, injury was not completely prevented.

Adult↗
PubMed2005

Seasonal differences in the secretion of luteinising hormone and prolactin in response to N-methyl-DL-aspartate in starlings (Sturnus vulgaris).

In birds, unlike mammals, seasonal changes in reproductive function are associated with marked changes in the amount of gonadotrophin-releasing hormone (GnRH) stored in the hypothalamus. Prolonged exposure to long photoperiods leads to photorefractoriness after the breeding season. Photorefractory birds have low hypothalamic concentrations of chicken GnRH-I (cGnRH-I). Exposure to short photoperiods results in renewed cGnRH-I synthesis and increased hypothalamic stores. Birds are then photosensitive and subsequent exposure to an increase in photoperiod results in increased cGnRH-I secretion and gonadal maturation. However, it is unclear whether the reverse is true at the time of gonadal regression during long photoperiods (i.e. that a decrease in GnRH-I synthesis precedes regression). Hypothalamic stores of cGnRH-I, and possibly therefore of releasable GnRH-I, decrease after regression. Single injections of the glutamate agonist N-methyl-DL-aspartate (NMA) were used as a probe to assess releasable stores of cGnRH-I in male starlings at four physiologically different reproductive stages. Treatment induced the greatest increase in luteinising hormone (LH) in photosensitive birds in January, and a slight increase in sexually mature birds in April. There was a slight but significant increase in June, immediately after testicular regression, but no increase in fully photorefractory birds in September. These data confirm that photorefractoriness is associated with a lack of releasable cGnRH-I, but that decreased synthesis of cGnRH-I is not the proximate cause of regression. There was an increase in prolactin in response to NMA at all times. The magnitude of the response was proportional to pre-treatment concentrations, with the greatest response in June. It is suggested that high circulating prolactin may fine-tune the timing of gonadal regression in advance of the inhibition of cGnRH-I synthesis.

Animals↗
PubMed2005

What is the role of the research ethics committee? Paternalism, inducements, and harm in research ethics.

In a recent paper Edwards, Kirchin, and Huxtable have argued that research ethics committees (RECs) are often wrongfully paternalistic in their approach to medical research. They argue that it should be left to competent potential research subjects to make judgments about the acceptability of harms and benefits relating to research, and that this is not a legitimate role for any REC. They allow an exception to their overall antipaternalism, however, in that they think RECs should have the power to prohibit the use of financial inducements to recruit research subjects into trials. In this paper it is argued that these claims are unjustified and implausible. A sketch is provided of an alternative model of the role of the REC as an expert body making judgments about the acceptability of research proposals through a consensual weighing of different moral considerations.

Attitude to Health↗
PubMed2005

ECG abnormalities in co-proxamol (paracetamol/dextropropoxyphene) poisoning.

OBJECTIVES: 1) To investigate ECG changes following co-proxamol (paracetamol 325 mg and dextropropoxyphene 32.5 mg) overdose in comparison to co-codamol (paracetamol and codeine) or co-dydramol (paracetamol and dihydrocodeine) in a prospective study. 2) To examine the relationship between estimated dextropropoxyphene dose and ECG changes in a larger patient population. BACKGROUND: Co-proxamol is a common cause of drug-induced death and hospital admission in the United Kingdom. ECG changes following dextropropoxyphene have been reported in animals and man, including QRS prolongation. METHODS: The prospective study was conducted on 15 patients and controls with overdose. A retrospective study of a cohort of 159 co-proxamol overdoses from a combined data set from Edinburgh and Newcastle, Australia was also conducted. The measured or estimated "four hour" plasma paracetamol level was used as a surrogate of the amount of dextropropoxyphene ingested. RESULTS: In the prospective study co-proxamol overdose caused statistically significant QRS prolongation (mean [95% CI] 99.36 [96.19, 102.53] msec), compared to the other combination opioid-paracetamol products (82.84 [80.81, 84.88] msec) but no effect on PR or QTc. QRS duration increase was evident soon after exposure and remained prolonged and stable over the following 24 h. In the retrospective cohort study a dose dependency of effect on QRS was documented, although the correlation coefficient relating paracetamol level to effect was relatively weak (r = 0.338, Sig. [2-tailed] 0.003, n = 74). CONCLUSIONS: QRS is significantly prolonged in co-proxamol overdose, and this prolongation is dose dependent. These findings have clinical relevance to the management of patients with co-proxamol poisoning.

Acetaminophen↗
PubMed2004

Differential gene expression in the T-helper lymphocytes of obstructive sleep apnea patients treated with nasal continuous positive airway pressure (nCPAP).

Obstructive sleep apnea (OSA) is a disease with significant morbidity, increased risk of accidents attributed to daytime somnolence, and has been associated with cardiovascular complications. The treatment of choice for OSA is nasal continuous positive airway pressure (nCPAP). Some OSA patients, however, are unable to benefit from this therapy as they find nCPAP intolerable due to the related nasal inflammation. It is hypothesized that nCPAP may cause nasal inflammation in these patients by inducing changes in the expression of genes that encode interleukins (IL-3, IL-4, IL-6, IL-8, IL-13) or adhesion molecules (i.e., ICAM-1) in T-helper lymphocytes. An understanding of the underlying inflammatory mechanism could lead to specific interventions that render nCPAP therapy tolerable for these individuals.

Clinical Trials as Topic↗
PubMed2004

Hypothetical economic analysis of screening for left ventricular hypertrophy in high-risk normotensive populations.

BACKGROUND: Left ventricular hypertrophy (LVH) measured by echocardiography is a powerful independent marker of increased cardiovascular risk. The prevalence of echocardiographic LVH in patients with high cardiovascular risk appears to be high, even in patients currently considered normotensive. AIM: To ascertain the likely costs of screening for and treating echocardiographic LVH in normotensive patients at high risk of cardiovascular events. DESIGN: Hypothetical economic analysis. METHODS: Cost analyses were based on known costs of echocardiography, costs of selected cardiovascular medications and prevalence of normotensive LVH in at-risk populations, combined with treatment effect data from studies of hypertensive patients with echocardiographic LVH. RESULTS: Screening costs per case for echocardiographic LVH are likely to be low, because of the high prevalence of the condition and the low unit cost of echocardiography. Treatment costs are likely to be comparable to those currently deemed acceptable in treating high-risk cardiovascular populations, e.g. the HOPE study population. DISCUSSION: The costs of screening for and treating LVH in normotensive patients at risk of cardiovascular events do not appear to be prohibitively high. Trials of screening and treatment for normotensive LVH seem therefore to be warranted.

Antihypertensive Agents↗
PubMed2002

Studies of the field efficacy and safety of a single-dose Mycoplasma hyopneumoniae vaccine for pigs.

The field efficacy and safety of a single-dose Mycoplasma hyopneumoniae vaccine were evaluated in three-to five-week-old pigs. Two field efficacy studies were conducted, one in England with 673 pigs, and one in Germany with 719 pigs. The pigs were injected intramuscularly with either the vaccine or saline (control) at a ratio of 2:1 and reared under commercial conditions to slaughter weight. The efficacy of the vaccine was evaluated by comparing the lung lesions associated with infection with M. hyopneumoniae in the control and vaccinated animals postmortem. In both countries the vaccinated pigs had a significantly lower percentage of lung lesion scores, in England 5.7 v 10.2 per cent (P = 0.0022) and in Germany 3.9 v 7.7 per cent (P = 0.0056). In Germany the average daily weight gain (ADG) of the vaccinated pigs was significantly higher (639 g v 616 g) (P = 0.0205). In both countries and in both the treated and control animals there was a significant negative correlation between the ADG and the lung lesion score (P = 0.0001). Two safety trials were conducted, one in England and one in Germany, each with 75 pigs, and in each case 50 pigs were given the maximum batch release antigen titre of the vaccine and 25 were given saline. The safety of the vaccine was evaluated by observation for local and systemic reactions and any increases in rectal temperature. No abnormal reactions were observed in the vaccinated pigs and there was no significant difference between the mean peak rectal temperatures of the vaccinated and control pigs in either trial.

Animals↗
PubMed2002

A population-based study of intensive multi-agent chemotherapy with or without autotransplant for the highest risk Hodgkin's disease patients identified by the Scotland and Newcastle Lymphoma Group (SNLG) prognostic index. A Scotland and Newcastle Lymphoma Group study (SNLG HD III).

The aim of the study was to identify all patients with poor risk Hodgkin's disease (HD) using a numerical prognostic index in a defined population and to recruit them into a trial of intensive chemotherapy prednisolone, vinblastine, doxorubicin, chlorambucil, etoposide, bleomycin, vincristine, procarbazine (PVACE-BOP)x3+autotransplant (Arm A) versus PVACE-BOPx5 (Arm B) in first remission. In 10 years, the Scotland and Newcastle Lymphoma Group (SNLG) registered 930 patients with HD of whom 178 (19%) were identified as 'poor risk' by the SNLG index and were aged 16-59 years. 126/178 (71%) entered the study. Of the 120 confirmed poor risk HD cases, all completed PVACE-BOPx3 with a 93% Complete Response/unconfirmed Complete Response (CR/CRu) rate. Only 65/107 in CR accepted the randomisation. With a median follow-up of 6 years, both arms of the trial have a similar time to treatment failure (TTF) (Arm A 79%+/-11 versus 85%+/-7 Arm B, P=0.35). Advanced stage 'good risk' patients not included in the trial receiving standard therapy with CLVPP or ABVD had a 75% 5-year survival. The study demonstrates that PVACE-BOP therapy in the poorest risk group (58% had an IPI>/=3) produces excellent CR rates (93%) and overall survival with minimal toxicity, and that the substitution of autotransplant in first CR does not improve outcome. The use of the objective SNLG index accurately helped in the selection of the poorest risk group in this population study. The placing of a randomised control trial within the context of a population-based study of HD enhances the validity of the outcome.

Adolescent↗