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Biomedical subjects

C Nixon

Publications and source records attributed to C Nixon.

33 records · Page 2Linked to original sources
PubMed1989

Sedation during spinal anaesthesia: a case for the routine administration of oxygen.

We have studied the effect of sedation with midazolam on arterial oxygen saturation during spinal anaesthesia in two groups of patients: one group received supplementary oxygen, the other group breathed room air. A significant reduction in oxygen saturation was observed in patients not receiving supplementary oxygen; six of 15 patients in this group developed hypoxaemia or severe hypoxaemia which was corrected immediately by administration of oxygen. There were no episodes of hypoxaemia in any patient in the group receiving supplementary oxygen. It is concluded that oxygen should be administered routinely to patients receiving sedatives during spinal anaesthesia.

Aged↗
PubMed1988

Antagonism of ethanol and pentobarbital actions by benzodiazepine inverse agonists: neurochemical studies.

The benzodiazepine inverse agonist Ro 15-4513 has been shown to antagonize several behavioral effects of ethanol and to block the effects of ethanol on chloride flux across brain membranes. We used isolated mouse brain membranes to test whether Ro 15-4513 would reduce the effects of ethanol on membrane fluidity, voltage-dependent calcium channels, microsomal calcium release or binding of t-[35S]butylbicyclophosphorothionate. None of these actions of ethanol were altered by Ro 15-4513. The enhancement of gamma-aminobutyric acid (GABA)-activated chloride flux produced by ethanol or pentobarbital was antagonized partially by Ro 15-4513. Another inverse agonist, FG 7142, was more effective than Ro 15-4513 as an antagonist of ethanol actions on chloride flux. These results demonstrate that the ethanol antagonist action of Ro 15-4513 is specific for GABA-activated chloride flux and does not extend to other neurochemical actions of ethanol. The inverse agonist action (i.e., inhibition of GABA-activated chloride flux tested in the absence of ethanol) of Ro 15-4513 and FG 7142 was revealed by pretreatment of mice in vivo with ethanol. This raises the possibility that ethanol exposure increases the inverse agonist actions of Ro 15-4513 and related drugs and that these inverse agonist actions contribute to the ethanol antagonism observed in vivo and in vitro.

Animals↗
PubMed1987

Laser treatment for tracheobronchial tumours: local or general anaesthesia?

Ninety seven patients with tracheobronchial tumours have been treated with the neodymium yttrium-aluminium-garnet (Nd YAG) laser over a period of 33 months. Fifty one of these patients were treated under local anaesthesia and 46 under general anaesthesia. The results obtained with the two methods have been compared retrospectively. The numbers of patients responding to treatment, the magnitude of the response, and the duration of palliation were similar in the two groups; significantly more treatment sessions, however, were required during each course of treatment under local anaesthesia. This advantage of general anaesthesia was thought to arise from the ability to continue treatment for longer and with greater efficiency. The use of the rigid bronchoscope with jet ventilation under general anaesthesia was also thought to provide better control of the airway and to allow more efficient clearance of blood and mucus. Two operative deaths occurred under local anaesthesia, when bleeding led to asphyxiation, but none have occurred under general anaesthesia. Treatment under general anaesthesia is not, however, without risk and is potentially hazardous in patients with severe chronic hypoxic lung disease.

Aged↗
PubMed1985

Macrophage chemotaxis in experimental tooth movement in the rat.

Extracts from tissue surrounding teeth being moved contained chemotactic activity for peritoneal exudate cells (PEC). The tissue was homogenized, extracted and diafiltered using a 100,000 mol. wt cut-off filter. The filtrate contained statistically-significant chemotactic activity, whereas the retentate did not. Further fractionation of the filtrate using an isoelectric focusing column produced a filtrate fraction in the pH range between 5.0 and 6.8 which was chemotactically active. This sample was analysed for purity and mol. wt using sodium dodecylsulphate polyacrylamide-gradient gel electrophoresis (SDS-PAGE). Gels of the active fraction stained with Coomassie blue showed two distinct bands with molecular weights of 69,000 and 60,000.

Animals↗
PubMed1985

Venovenous perfusion in ECMO for newborn respiratory insufficiency. A clinical comparison with venoarterial perfusion.

Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) has been successful in the treatment of newborns less than 1 week of age and greater than 2000 gm birthweight with respiratory failure resistant to current medical and surgical management. While VA ECMO supports the heart as well as the lungs, it has the disadvantage of requiring carotid artery ligation and the possibility of perfusing air bubbles or particles into the arterial tree. We have treated 11 newborns with respiratory failure with venovenous (VV) ECMO returning the oxygenated blood to a cannula in the distal iliac vein. We compared these patients with 16 patients treated during the same period of time with VA ECMO. Three of the 11 VV patients required conversion to VA ECMO because of inadequate oxygenation and unstable hemodynamic situations. Ten of the 11 VV patients survived. Eleven of the 16 VA patients survived. The better survival in these patients treated with VV ECMO is attributed to their more favorable initial condition compared to patients treated with VA ECMO. The disadvantages of VV ECMO include a longer operative time to place the cannulas, groin wound problems, and persistent leg swelling along with the necessity to convert some patients to VA ECMO. Although this experience demonstrates that newborns with severe respiratory failure can be supported with VV ECMO, the complications and lack of practical advantages over VA lead us to recommend VA ECMO for routine clinical use at present.

Female↗
PubMed1985

Laser therapy in 100 tracheobronchial tumours.

One hundred patients with tracheobronchial tumours were treated with the neodymium YAG (yttrium-aluminium-garnet) or argon laser for symptoms of airways obstruction caused by tumour (59 cases), complete collapse of a lung (17 cases), or recurrent haemoptysis (24 cases). Seventy four of them had relapsed or failed to respond to radiotherapy or chemotherapy and all were inoperable. Objective improvement in results of lung function tests or haemoptysis diary charts was seen in 37 patients with airways obstruction (63%), five (29%) with collapsed lung, and 14 (58%) with haemoptysis. Overall, 68 patients had symptomatic benefit and there was objective improvement in 56. Two deaths occurred in 288 treatment sessions both occurring as a result of asphyxia from minor haemorrhage in patients with advanced cylindromas and critical narrowing of the trachea or single remaining bronchus. In suitable patients with intraluminal tumour laser phototherapy is a valuable addition to conventional treatment.

Adult↗
PubMed1981

Prediction of the WAIS-scores from the 1973 Henmon-Nelson revision.

Administered the 1973 revision of the Henmon-Nelson and the WAIS to 100 psychiatric patients. The correlation of Henmon-Nelson raw scores with WAIS Full Scale scaled score was .83, which compared favorably with correlations run between several other short IQ tests and the WAIS in similar samples drawn from the same setting in earlier studies. However, the Henmon-Nelson did not appear able to estimate the WAIS IQs of low-intelligence Ss or aged persons with consistent accuracy. The validities of short IQ tests and current practices in the selection of WAIS surrogates were discussed.

Adult↗
PubMedDate not supplied

The process of restructuring and the treatment of obesity in women.

Obesity is a prevalent health behavior that is difficult to treat because of its complexity, constraints on provider time, and negligible insurer reimbursement. In this comparative case study the authors describe two obese women's weight loss and lifestyle change efforts while enrolled in a nine-month, multidisciplinary weight loss program. The researchers conducted three semistructured interviews during six months. Eight major themes were identified: (1) support networks. (2) internalization/externalization, (3) routines, (4) relapse, (5) change in perspective, (6) reward/punishment, (7) emotional issues, and (8) life balance. These themes parallel Johnson's three-stage theory of cognitive restructuring. (See Johnson, 1990, "Restructuring: An Emerging Theory on the Process of Losing Weight." Journal of Advanced Nursing, 15, 1289-1296.) Researchers reveal that complex health problems are replete with social and psychological factors that may undermine treatment success. Understanding a client's experience while attempting behavior change is crucial for the development of interventions that address difficult and costly health behaviors.

Adaptation, Psychological↗