Placental propofol transfer and fetal sedation during maternal general anaesthesia in early pregnancy.
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Abortion, Legal↗
Biomedical subjects
C Shannon
Publications and source records attributed to C Shannon.
Rearing condition and plasma cortisol in rhesus monkey infants.
Previous studies comparing plasma cortisol levels in mother-reared and nursery-reared rhesus monkey infants under baseline and stress conditions have reported conflicting findings. Differences in subject age, procedures, and specific rearing history may account for many of the discrepant findings. In the present study, mother-reared infants from large social groups, peer-only reared animals, and infants reared with surrogates and limited peer contact were studied in different test conditions across the first 6 months of life. Infants were sampled under three conditions: following a neonatal assessment at Days 14 and 30, immediately upon capture on Day 60, and after 30-min isolation periods on Days 90, 120, and 150. Mother-reared infants exhibited higher cortisol levels on Days 14 and 30 than did both types of nursery-reared infants. In addition, Day 60 basal values of mother-reared infants were higher than those of both peer-reared and surrogate/peer-reared infants. However, on Days 90, 120, and 150, both mother-reared and peer-reared infants exhibited higher cortisol levels in response to separation and 30-min isolation than did the surrogate/peer-reared infants. These differences may reflect group-specific variations in physical environment, capture time, feeding regimen, or diurnal HPA axis rhythms.
Animals↗
Placental transfer of fentanyl in early human pregnancy.
To investigate the transfer of fentanyl across the early human placenta, we have collected samples of maternal blood and fetal fluids and/or blood, simultaneously, between 5 and 22 min following an intravenous bolus of fentanyl (1.5 microg/kg) to the mother. The pregnancies were between 6 and 16 weeks of gestation and scheduled for elective termination of pregnancy under general anaesthesia. Total fentanyl concentration was determined by radioimmunoassay in 11 pairs of first trimester maternal serum and fetal coelomic fluid samples, 14 pairs of maternal serum and amniotic fluid samples, seven series of first trimester maternal serum and coelomic and amniotic fluid samples, and 10 series of early second trimester maternal and fetal sera and amniotic fluid samples. Fentanyl was not detected in coelomic fluid samples at any gestational age and in amniotic fluid samples collected after 12 weeks of gestation. Measurable concentrations of fentanyl were found in maternal serum collected within 15 min after the initial bolus and in fetal serum collected between 10 and 12 min later. These findings indicate that fentanyl is transferred across the early placenta into the amniotic cavity and fetal blood circulation but not into the exocoelomic cavity. The distribution of this molecule inside the early gestational sac is probably influenced by the increased binding by maternal and fetal sera, its short half-life of distribution and the specific biology of the fetal fluid formation and composition.
Amniotic Fluid↗
Electrical potential difference between exocelomic fluid and maternal blood in early pregnancy.
The forces that drive transfer of solutes between maternal blood and embryo in early human pregnancy are poorly understood. The aim of this study was to determine whether there is an electrical potential difference (PD) between maternal blood and the exocelomic cavity and between maternal blood and the amniotic cavity in the normal human conceptus at or before 10 wk of pregnancy. We measured PD between a saline-filled catheter in a forearm vein of women undergoing termination of pregnancy for psychological reasons in the first trimester and a second saline-filled catheter in the exocelomic cavity or amniotic cavity of their conceptus. The mean (+/- SE) maternal blood/exocelomic cavity PD in eight women was 8.7 +/- 1.0 mV and the mean maternal blood/amniotic cavity PD in four of the women was 6.7 +/- 1.3 mV, embryo side negative for both sets of measurement. These data show that there is a PD between maternal and embryonic extracellular fluid in the first trimester that will directly influence exchange of ions between the two compartments.
Amniotic Fluid↗
Community perceptions of health, illness and care: identifying issues for indigenous communities.
Community meetings, interviews with key informants, and focus groups were used to document major health concerns and problems among Indigenous women in Queensland, as part of the Australian Longitudinal Study on Women's Health. In this article, we analyze understandings of "community" as used in Australian health research and among Indigenous women. We then examine health issues as identified and experienced by women and explore the gaps that exist between community concerns, individual health status, and service delivery.
Adolescent↗
Types I and III collagen in the tissue capsules of titanium and stainless-steel implants.
Collagen plays an important role in wound healing and as such is present in connective tissue capsules around implanted materials. The proportion of type I collagen to type III collagen is lower during wound healing than that found in normal dermis, but the amount of type I collagen gradually increases and type III decreases as healing continues. The intent of this research was to investigate a possible correlation between implant metals and type I and type III collagen formation in the ensuing soft-tissue capsules. Smooth implants of grade 4 commercially pure titanium and 316L stainless steel were placed via injection needle into the subcutaneous tissue of 12 rats for 6 weeks. The soft-tissue capsule that formed around each implant was evaluated histologically and by immunofluorescence. Although the two metal implant types differ in many respects, they were chosen for their differences in surface conductivity. Titanium oxide is semiconducting, whereas the oxide of stainless steel is conducting. Impedance spectroscopy was used for conductivity analysis of the surface. No qualitative differences were found in amount of type I or type III collagen in the capsules of the two metals. However, the capsules around titanium stained for type I collagen were thicker than capsules around stainless steel. In addition, type I collagen showed evidence of a greater association with densely packed, highly orientated collagen fibers.
Animals↗
EEG arousal during laryngoscopy and intubation.
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Anesthetics, Intravenous↗
Extrarenal potassium homeostasis with maximal exercise in end-stage renal disease.
Serum potassium levels rise substantially during vigorous exercise as a result of the release of potassium from contracting muscle cells. Widespread use of erythropoietin has allowed for increased exercise capacity in patients with ESRD, raising the concern for severe exertional hyperkalemia. The aim of this study was to determine whether ESRD is associated with alterations in potassium and the neurohumoral mediators of extrarenal potassium disposal with maximal exercise. Eight stable hemodialysis patients (aged 37 +/- 16 yr, mean +/- SE) and eight healthy control subjects (aged 44 +/- 13 yr) exercised to exhaustion, using a graded cycle ergometer. There were no significant differences in exercise performance between groups as assessed by peak work rate, maximal oxygen consumption, and rate pressure product. Although the baseline potassium level was higher in the dialysis group (5.0 +/- 0.2 mEq/L) than in control subjects (4.5 +/- 0.1 mEq/L), both groups had a similar pattern of increase during exercise (with an increment of approximately 1 mEq/L) and a similar return to baseline after exercise. However, the dialysis patients had higher basal norepinephrine levels (820 +/- 104 versus 441 +/- 56 pg/mL, P < 0.01) and a greater response to exercise (3122 +/- 429 versus 1696 +/- 424 pg/mL, P < 0.01), higher basal insulin levels (11 +/- 1 versus 7 +/- 1 microU/mL, P < 0.05), higher insulin post-exercise levels (19 +/- 3 versus 11 +/- 1 microU/mL, P < 0.05), and higher basal aldosterone levels (621 +/- 250 versus 109 +/- 13 pg/mL, P < 0.05) with an increase response to exercise (1100 +/- 350 versus 350 +/- 17 pg/mL, P < 0.05). In summary, despite higher basal potassium, dialysis patients have normal potassium responses to maximal exercise. More vigorous insulin, catecholamine, and aldosterone levels may contribute to the maintenance of extrarenal potassium homeostasis in ESRD.
Adult↗
Social and cultural differences affect medical treatment.
This paper seeks to identify some of the significant health issues for Aboriginal people and the obstacles they often encounter in assessing the medical system. Clearly, the latter largely result from problems in communication, which can be addressed by seeking to establish good relationships. Whether the Aboriginal patients live in a traditional or remote community, a rural country area, or a large urban setting, an understanding of their conceptualization of their conditions can greatly enhance the communication process. Mobbs points out that this not only improves the clinical encounter, it also helps to overcome barriers of mistrust, misunderstanding and anxiety between the client and the professional.
Australia↗
Chronic fatigue syndrome. A review from the general practice perspective.
There is no doubt that the chronic fatigue syndrome exists. It is a condition that is debilitating and of unknown cause. Research into chronic fatigue syndrome demonstrates possible psychiatric or organic causes. The truth may be somewhere in between. Evidence for the existence of an ongoing chronic infection is now not convincing. Treatment should be based on supportive counselling, explanation, psychiatric help (both pharmacological and non pharmacological) and a graded programme of increased activity with the eventual aim of resumption of full functioning.
Antibodies, Viral↗
Ventilators: in-service performance with Biotek ventilator testers.
The assessment of mechanical ventilator performance is a complex task requiring measurement of a number of different transducers under a variety of conditions. The use of dedicated testing equipment can alleviate the complexity of the experimental apparatus. This paper assesses the accuracy and versatility of the Biotek VT-1 and VT-2 dedicated ventilator testers. Results show that the testers perform within the manufacturer's specifications and have the required flexibility to be used in investigating faults reported with ventilators.
Equipment Failure↗
Electrode reactions of well-characterized adsorbed molecules.
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Electrochemistry↗
Normalization of abnormal diurnal weight gain among chronically psychotic geriatric patients. Is abnormal diurnal weight gain a risk factor in chronic psychosis?
We studied 20 geriatric and 87 nongeriatric chronically psychotic male inpatients, 16 acutely psychotic male control subjects, and 14 male normal subjects. The subjects were weighed at 7 a.m. and 4 p.m. weekly for 3 weeks. We normalized the diurnal weight gain (NDWG) as a percentage by subtracting the 7 a.m. weight from 4 p.m. weight, multiplying the difference by 100, and then dividing the result by the 7 a.m. weight. NDWG was .509% +/- .337%, 2.209% +/- 1.529%, .631% +/- .405%, and .533% +/- .410%, among the geriatric men, nongeriatric men, control subjects, and normal subjects respectively. Differences in diagnoses and drugs did not explain these findings. We hypothesize that abnormal diurnal weight gain may be a risk factor for premature death among chronically psychotic inpatients.
Adult↗
Diurnal weight gain among patients with mental retardation.
We compared the diurnal weight gain of 46 patients with mental retardation to that of 21 patients with organic mental syndromes. They were weighed at 7 a.m. and 4 p.m. weekly for 3 weeks. We normalized the diurnal weight gain as a percentage by subtracting the 7 a.m. weight from the 4 p.m. weight, multiplying the difference by 100, and dividing the result by the 7 a.m. weight. Normalized diurnal weight gain was abnormal among one fourth of patients with mental retardation and two thirds of those with organic mental syndromes. Differences in age, sex, baseline weight, antipsychotic drugs, lithium, carbamazepine, blood pressure, and pulse did not explain our results. We believe that our findings provide additional evidence to separate patients with mental retardation from those with psychosis.
Adult↗
Atrial tracking (synchronous) pacing in a pediatric and young adult population.
One hundred pediatric and young adult patients underwent implantation of an atrial tracking pacemaker. Seventy-four pacemakers paced in an atrioventricular (AV) sequential mode at the lower rate limit (DDD) while 26 paced in a ventricular demand mode at the lower rate limit (VDD). Five patients required reoperation during follow-up of 1 month to 2.5 years (mean 1.5 years). Six additional patients required programming to ventricular demand (3) or AV sequential (3) pacing, because of development of sinus bradycardia (2), atrial sensing problems (1) or pacemaker-mediated tachycardia (3). Pulse generators that could sense atrial signals less than 1.0 mV and had a programmable atrial refractory period did not require reprogramming out of the atrial tracking mode. No patient developed atrial flutter or fibrillation. Sensing problems during exercise occurred in 37% of the first 60 pacemakers but in none of the last 40, which had improved electronic components. Atrial tracking pacing is feasible in pediatric and young adult patients.
Adolescent↗
Use of cardiac pacing after the Mustard operation for transposition of the great arteries.
The most frequent complication of the venous redirection (Mustard or Senning) operation for transposition of the great arteries is cardiac arrhythmia. Drug treatment of tachyarrhythmia often worsens bradyarrhythmia. Pacemakers can now treat both arrhythmias. The technique for implantation of pacemakers after redirection for transposition has changed over time from thoracotomy to subxiphoid to transvenous. Atrial pacing is almost always the mode of choice since the electrophysiologic abnormality is sinus node dysfunction with intact atrioventricular conduction. Twenty-nine patients aged 3 to 19 years (mean 9.6) had implantation of a pacemaker a mean of 5.5 years (range 1 to 14) after undergoing the Mustard operation for transposition of the great arteries. Symptoms referable to bradycardia were eliminated in each case. Four patients who received an antitachycardia pacemaker no longer have symptomatic tachycardia. Four patients have required reoperation, three because of lead problems and one because of traumatic erosion of the pacemaker. Pacemakers provide excellent relief of symptoms after the Mustard or Senning operation. Transvenous atrial automatic antitachycardia pacemakers offer the best combination of ease of implantation and symptomatic relief.
Adolescent↗
Use of atrial pacing in a young population.
Forty pediatric and young adult patients (1-20 years; mean, 11 years of age) had implantation of atrial demand (AAI) pacemakers over a 5.5 year period. Nineteen were implanted by epicardial technique and 21 transvenously. Standard lithium single chamber pulse generators and standard atrial leads were used. Operative stimulation thresholds were better for transvenous leads than for epicardial (0.75 volts vs. 1.5 volts at 0.5 ms) (p less than 0.05). Pulse width thresholds at a mean of 1.5 years were not significantly different (0.11 ms for transvenous vs. 0.18 for epicardial). No patient developed AV block. Eight patients (four epicardial and four endocardial) required reoperation during the mean 3.5 year follow-up--four because of lead problems and four because of persistent tachycardia. Of the six patients who received an automatic antitachycardia pacemaker, only one had persistent symptoms while seven of eight who received a standard unit continued to have symptoms. Twenty-eight of 29 symptomatic patients without tachycardia became asymptomatic. Atrial pacing appears to be a safe and effective therapy for children with sick sinus syndrome.
Adolescent↗
Long-term follow-up of pulse width threshold of transvenous and myo-epicardial leads.
Postoperative pulse width thresholds were measured at a constant of 5 volts in 140 patients. In 41 patients, transvenous atrial and/or ventricular leads were implanted at a median age of 13 years (3-78 yrs). Myo-epicardial leads were implanted in 99 patients at a median age of 8 3/4 years (1 wk to 76 yrs). The initial rapid rise of threshold was found to persist not longer than to the third follow-up period of 11 days to 5 weeks in all atrial and transvenous ventricular leads; in myo-epicardial ventricular leads it persisted until the period of more than 5 weeks to 6 months. During initial rise, pulse width threshold m + sem did not exceed 0.45 ms. We therefore suggest that a pulse width setting of 0.5 ms at 5 V is a safe setting for this period. In only one patient did a late rise of threshold occur. The comparison of pulse width thresholds of transvenous versus myo-epicardial leads showed lower mean values for transvenous atrial leads in each follow-up period, but the difference was not statistically significant. The pulse width thresholds of transvenous ventricular leads were significantly lower than those of myo-epicardial leads in some follow-up periods. We therefore conclude that transvenous leads have a slight advantage with regard to postoperative pulse width threshold.
Adolescent↗