Ethics and clinical research in obstetric anaesthesia.
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Analgesia, Epidural↗
Biomedical subjects
B Morgan
Publications and source records attributed to B Morgan.
Effects of nerve growth factor and acetyl-L-carnitine arginyl amide on the human neuronal line HCN-1A.
The HCN-1A clonal cell line, derived from the cortical tissue of a patient with unilateral megencephaly, was shown to differentiate into a mature neuronal-like state in the presence of the nerve growth factor, dibutyryl cyclic adenosine, 3',5'-monophosphate and either 1-isobutyl-3-methylxanthine or forskolin. Differentiation was assessed by measuring the percentage of cells that displayed branched, varicose processes that stained for synaptophysin. Treatment of cultures with a cocktail containing forskolin increased immunocytochemical staining for gamma aminobutyric (GABA), neurofilament protein and the nerve growth factor receptor species p75NGFR. Treatment with acetyl-L-carnitine alone had some effects on the cell morphology while acetyl-L-carnitine arginyl amide and nerve growth factor together increased the GABA content. Positive staining levels for the neurotransmitters gamma aminobutyric acid, glutamate, somatostatin, cholecystokinin and vasoactive intestinal polypeptide were measured quantitatively for HCN-1A under basal conditions.
1-Methyl-3-isobutylxanthine↗
Maternal and fetal haemodynamic effects of spinal and extradural anaesthesia for elective caesarean section.
Serial haemodynamic investigations were performed in 32 women who were allocated randomly to receive either spinal or extradural anaesthesia for elective Caesarean section. Cardiac output was measured by Doppler and cross-sectional echocardiography at the aortic valve. Doppler flow velocity waveforms were recorded also from the umbilical artery. Preloading with Ringer lactate solution 1 litre increased cardiac output in both groups. After injection of bupivacaine, cardiac output remained increased in the extradural group, but decreased in the spinal group. This was associated with an increase in umbilical artery pulsatility index in the spinal group. Umbilical artery pH was less in the spinal group (7.22 vs 7.27), although no neonate was depressed at birth. The maximum percentage change in cardiac output and umbilical artery pulsatility index correlated with umbilical artery pH (r = 0.54, r = 0.72, respectively). There was no significant correlation with change in arterial pressure.
Adult↗
Can out-of-hours work by junior doctors in obstetrics be reduced? and role of senior house officer in the labour ward.
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Medical Staff, Hospital↗
A comparison of standard and rapid infusion methods of liver preservation during multi-organ procurement.
The standard and rapid infusion techniques of liver preservation during multi-organ procurement were compared in the porcine model of orthotopic liver transplantation. Group I (n = 48) had the standard method of procurement while group II (n = 34) underwent the rapid infusion method. Donor liver function was compared between the two methods using the criteria of survival, liver function tests and histology. No statistically significant difference was evident between the two groups. Because of logistical advantages, the rapid infusion method is recommended as the technique of choice during multi-organ procurement.
Animals↗
Lipid screening: is it enough to measure total cholesterol concentration?
OBJECTIVES: To determine whether measurement of total cholesterol concentration is sufficient to identify most patients at lipoprotein mediated risk of coronary heart disease without measurement of triglyceride and high density lipoprotein (HDL) cholesterol concentrations. DESIGN: Cross sectional screening programme. SETTING: Six general practices in Oxfordshire. PATIENTS: 1901 Men and 2068 women aged 25-59. MAIN OUTCOME MEASURE: Cardiovascular risk as assessed by fasting venous plasma concentrations of total cholesterol, triglyceride, and HDL cholesterol. RESULTS: 2931 Patients (74% of those screened) had a total cholesterol concentration of less than 6.5 mmol/l. If the triglyceride concentration had not been measured in these patients isolated hypertriglyceridaemia (greater than or equal to 2.3 mmol/l) would have remained undetected in 185. Among these 185 patients, however, 123 were overweight or obese and only 18 (0.6% of those screened) had an increased risk associated with both a raised triglyceride concentration (greater than or equal to 2.3 mmol/l) and a low HDL cholesterol concentration (less than 0.9 mmol/l). Conversely, in the 790 patients with predominant hypercholesterolaemia (cholesterol concentration greater than or equal to 6.5 mmol/l and triglyceride concentration less than 2.3 mmol/l) measurement of HDL cholesterol concentration showed that 348 (9% of those screened) had only a moderately increased risk with a ratio of total to HDL cholesterol of less than 4.5 and 104 had a low risk with a ratio of less than 3.5. CONCLUSIONS: Fasting triglyceride and HDL cholesterol concentrations identify few patients at increased risk of coronary heart disease if the total cholesterol concentration is less than 6.5 mmol/l. HDL cholesterol and triglyceride concentrations should, however, be measured in patients with a total cholesterol concentration exceeding this value. Total cholesterol concentration alone may overestimate risk in a considerable number of these patients, and measurement of HDL cholesterol concentration allows a more precise estimate of risk. Measurement of the triglyceride concentration is required to characterise the lipoprotein abnormality. A patient should not be started on a drug that lowers lipid concentrations without having had a full lipoprotein assessment including measurement of HDL cholesterol concentration.
Adult↗
Prenatal alcohol exposure alters the development of sympathetic synaptic components and of nerve growth factor receptor expression selectivity in lymphoid organs.
Exposure to alcohol in utero has been associated with long-term immune deficits. In addition, adult mice exposed to alcohol prenatally display altered noradrenergic synaptic transmission selectively in lymphoid organs. This is consistent with the hypothesis that sympathetic neurons play an important role in immunomodulation. The development and maintenance of sympathetic neurons are critically dependent on nerve growth factor (NGF). Furthermore, NGF has been shown to modulate immune responses and NGF receptor expression has been localized to lymphoid organs. The present work examined the effects of prenatal alcohol exposure on the development and maturation of pre- and postsynaptic sympathetic components, including norepinephrine and beta-adrenoceptors, respectively, as well as the early expression of NGF receptors in lymphoid and other organs of the C57BL/6 mouse. Infant mice that were exposed to alcohol in utero displayed reduced levels of norepinephrine and beta-adrenoceptor density, as well as increased NGF receptor expression in the thymus and spleen, but not the heart. These selective changes may account, in part, for the persistent immune incompetence characteristic of fetal alcohol syndrome.
Animals↗
The relationship of free fatty acids with the binding of oestradiol to SHBG and to albumin in women.
Free fatty acid concentration, sex hormone binding globulin (SHBG) concentration, % free oestradiol and % SHBG-bound oestradiol were measured in fasting and non-fasting serum samples from 48 women. Free fatty acids were 128% higher (P less than 0.001) and % SHBG-bound oestradiol was 11% lower (P = 0.001) in fasting than non-fasting samples, but these changes were not significantly correlated (r = -0.16, P = 0.287). Mean SHBG concentration and % free oestradiol did not differ significantly between fasting and non-fasting samples. Between subject correlations were calculated for measurements from 30 premenopausal women: % free oestradiol was inversely correlated with SHBG and free fatty acids and positively correlated with Quetelet's Index; % SHBG-bound oestradiol was positively correlated with SHBG but was not consistently or significantly related to free fatty acids or Quetelet's Index. It was concluded that physiological increases in free fatty acid concentrations do not increase % free oestradiol and that free fatty acids are less important than SHBG concentration and perhaps other variables in determining differences between individuals in oestradiol binding to SHBG.
Adult↗
Growth factor-mediated protection in aging CNS.
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Adrenal Gland Neoplasms↗
Retinotopic representation of the bifoveate eye of the kestrel (Falco spraverius) on the optic tectum.
Like many diurnal raptors, the American kestrel or sparrow hawk, Falco sparverius, possesses two foveae in each eye. In this study, we used fundus photography and reversed ophthalmoscopy to plot the projection of these foveae onto the visual field, together with other retinal landmarks such as the pecten and ora terminali. From such data, it was determined that the central monocular fovea (CMF) and temporal binocular fovea (TBF) were separated by 36 deg and that the kestrel has 58 deg of binocular overlap when the eyes are appropriately converged. Single-cell and multi-unit recordings were used to systematically explore the tectal surface and map receptive fields (RF) onto a hemispheric screen. A retinotopic map of the tectal surface was produced from such data and revealed an expanded representation for each fovea on the tectum and a systematic increase in RF size from fovea to periphery. The functional significance of this organization is discussed.
Animals↗
Comparison of four local extradural anaesthetic solutions for elective caesarean section.
We have examined a combination of two local anaesthetics to see if the resultant solution is superior to the agents individually. This study shows that a mixture of bupivacaine and lignocaine provided an excellent alternative to bupivacaine alone, and was superior to 2% lignocaine with adrenaline for elective Caesarean section. By reducing the dose of bupivacaine used, the combination may reduce the risk of cardiotoxicity.
Adult↗
Unexpectedly extensive conduction blocks in obstetric epidural analgesia.
Life-threatening extensions of conduction block during obstetric epidural analgesia can be classified according to the risk to the mother. High blocks that occur in the presence of the anaesthetist should present a readily treatable problem. Reports of total spinal anaesthesia that occur with no anaesthetist in attendance call for a reappraisal of present practice. Changes in current anaesthetic practice, which might increase safety with epidural analgesia, are top-ups by midwives, but only when the anaesthetist is on the delivery suite; repeated assessment of the nature of the conduction block by an anaesthetist; and continuous infusions with anaesthetist-only top-ups.
Analgesia, Epidural↗
Nerve growth factor activity and aging in CNS.
This is a discussion of aging in CNS and the influence of the nerve growth factor (NGF) protein. The paper considers neuronal plasticity and neuronotrophic substances, neuronal cell death and the nerve growth factor protein, including its effects, receptors, and model systems for the study of CNS aging.
Aging↗
Hyperlipidaemia in general practice: three year follow up of an opportunistic screening project.
As part of the national lipid screening project 927 people with a plasma cholesterol level greater than 6.5 mM were detected by screening 4006 men and women aged 25-59 years. Three years later 801 of the 878 patients eligible for a follow-up study (91%) had been followed up at least once. The median number of follow-up visits was two. The bulk of the workload fell on the nursing staff. The mean decrease in cholesterol level was 8-14% in those receiving dietary advice only, 15-25% in those receiving additional drug treatment and 12% for all patients. A proportion of this decrease must be attributable to regression to the mean, loss to follow up when patients were doing well, and the patients' knowledge of their follow-up date. Data on a group of patients not attending for regular follow up suggest that regression to the mean could account for up to 7% of the cholesterol reduction observed. Screening for hyperlipidaemia in general practice is feasible when the necessary infrastructure is provided, but even with a fairly conservative protocol 3% of those screened received drug treatment.
Adult↗
Screening for congenital dislocation of the hip by child-health nurses in Western Australia.
The child-health nurse screening programme for the presence of congenital dislocation of the hip in Western Australia was evaluated by the use of data that were collected as a routine from the Congenital Malformations Registry, the records of child-health nurses and the Hospital Morbidity System. The programme performed well operationally, with a sensitivity of 68.5%, a specificity of 98.8%, and a positive predictive value of 15.1%. Of the children who were born in the study period (1981-1983), 450 children were diagnosed with congenital dislocation of the hip, and 46 (10.2%) of these children required 104 hospital admissions for the treatment of their dislocation. Of the children whose hips were found to be dislocated in screening (those who were screened as "true-positive" cases), 10.1% were hospitalized, whereas 16.1% of those children who were missed by screening (who screened as "false negative") required hospitalization (95% confidence interval [CI] for the difference in proportions, -7.8% to 19.9%). A comparison of the measures of hospitalization was made between the children who were found to be "true positive" on screening and the children whose dislocation was diagnosed in the hospitals of their birth--a group that generally is considered to show the best outcome. A somewhat-higher proportion of children who were screened as "true positive" required an open surgical procedure (5.0% of children compared with 2.8% of children; 95% CI for the difference, -2.1% to 6.5%). The differences in the other measures of hospitalization between the two groups were small.
Child↗
Expression of nerve growth factor receptors by human peripheral blood mononuclear cells.
In the rat, nerve growth factor (NGF) has been shown to affect immune reactivity by binding to cell surface receptors on a subpopulation of splenic mononuclear cells. This binding occurs in a specific and saturable fashion to what appear to be low-affinity (type II) NGF receptors (NGFR). Immunofluorescence studies here showed that NGFR are also present on a proportion of human peripheral blood mononuclear cells (PBMC). Equilibrium binding studies demonstrated that the binding of NGF to its receptors on PBMC occurs with a single equilibrium binding constant (mean) of 2.11 X 10(-9) M. The number of receptors per cell was determined to be approximately 6.94 X 10(3) receptors/cell. These results would suggest a role for NGF in the regulation of immune function in man, as well as in animals.
Cell Membrane↗
Effect of protein malnutrition on the composition of submandibular glands of aged rats.
Fifty 22-month-old male Sprague-Dawley rats were fed for 8 weeks ad libitum with either a 20% protein diet (control) or a 5% protein diet (protein malnourished group). Submandibular glands were removed, weighed and homogenate prepared. After the low protein diet, there was a slight but significant decrease in body weight, glandular content of total protein (mg/g tissue), kallikrein activity/mg protein and glutamine-rich peptide. In contrast, the gland weight, DNA and mucin content were not changed by feeding a low protein diet. Thus in aged rats submandibular glands are only modestly affected by protein malnutrition and the effects on gland-specific proteins vary.
Aging↗
Effect of time and adrenaline on the feto-maternal distribution of bupivacaine.
Following lumbar extradural analgesia with 0.5% bupivacaine, the placental transfer of bupivacaine was examined in 40 women undergoing elective and 40 women undergoing emergency Caesarean section. Within each group, the patients received randomly either plain bupivacaine or bupivacaine with adrenaline 1 in 200,000. Plasma bupivacaine concentrations were measured in blood samples taken simultaneously at delivery from the umbilical vein (UV), umbilical artery (UA) and maternal vein (MV). Bupivacaine concentrations in MV, UV and UA were not significantly affected by the presence of adrenaline, but were positively correlated with first dose to delivery interval (FDD) while MV and UV were inversely correlated with last dose to delivery interval (LDD). Mean ratio of UV:MV concentrations of bupivacaine was 0.346 and for UA:MV it was 0.305. There was no significant correlation between any fetal:maternal ratio and FDD or LDD. UA:UV ratio appeared to increase towards unity 30-40 min after the last dose. The presence of adrenaline was associated with an increase in UA:UV in the elective group (P less than 0.01). In eight patients who received adrenaline there was reverse placental transfer (UA:UV greater than 1). There was no evidence of progressive fetal accumulation of bupivacaine beyond 30-40 min.
Anesthesia, Epidural↗