Biomedical subjects
Publications and source records attributed to C Thornton.
'Health for all children' emphasises health promotion and parental involvement in child health surveillance checks. Heavy caseloads and the need to incorporate these principles in their practice prompted an Oxfordshire team of health visitors to introduce group health assessments. Here they describe the new approach and the response from parents.
Auditory (AER) and somatosensory evoked responses (SSER) were recorded simultaneously in eight patients under anaesthesia before surgery. We studied the effects of equi-MAC end-expiratory concentrations of isoflurane (0.65-0.75%) and nitrous oxide (60-65%). The anaesthetics were changed at random in three consecutive 10-min periods so that each patient received both drugs. From the AER recorded from the vertex and inion, Pa and Nb latency and amplitude were measured. N13, P20 latency and N13 amplitude were measured from SSER recordings from the neck and P15, N20, P25, N35, P45 latency and P15-N20, N20-P25, P25-N35 and N35-P45 amplitude from the scalp over the hand area of the sensory cortex. Compared with nitrous oxide, isoflurane significantly increased the latencies of the AER waves Pa (P = 0.02) and Nb (P = 0.02), and the SSER waves N20 (P = 0.001) and P25 (P = 0.04). We were unable to demonstrate significant differences in Pa and Nb amplitude between isoflurane and nitrous oxide that we had seen previously. However, the amplitude of the SSER wave N20 was reduced significantly by nitrous oxide compared with isoflurane (P = 0.0004). This wave (N20) is thought to emanate from the thalamo-cortical radiations, and our findings may be explained by an analgesic effect of nitrous oxide mediated by endogenous opioids.
We have investigated the relationship between the auditory evoked response (AER) and simple tests of conscious awareness at four end-expiratory concentrations (0.0, 0.1, 0.2 and 0.4 MAC) of isoflurane in oxygen in each of eight anaesthetist volunteers, in random order, at least 1 week apart. The early cortical AER was recorded from electrodes at the vertex and inion. Amplitudes of the waves Pa, Nb and Pc and latencies of the waves Na, Pa, Nb, Pb and Nc were measured. All the AER variables were highly significantly related to end-expiratory anaesthetic concentration. Amplitudes decreased and latencies increased progressively with increasing anaesthetic concentration. The AER variables were also highly significantly related to the level of response. Amplitudes were greatest and the latencies shortest when there was full response to command. (Nb latency increased from 47.5 to 54.5 ms between partial and no response.) The close correlation between the effects of concentration and level of response, and between concentration and the AER implied that it was difficult to demonstrate those changes in the AER which specifically relate to changes in response. At 0.2 MAC, however, which was the concentration at which all subjects showed some deficit, the response to a shock word was distinguished clearly by Nb latency. In eight of 24 possible comparisons (eight AER variables and three types of psychological test) the AER fitted the response more closely than concentration.
Four patients with Carney's complex, one sporadic and three familial, are described. The sporadic case was a young male with centrofacial lentigines, who developed cyclical Cushing's syndrome secondary to bilateral pigmented nodular adrenocortical disease, two separate left atrial myxomas, and buccal mucosal myxomas. The three familial cases, who all had varying degrees of centrofacial/mucosal lentigines and cutaneous myxoid tumours, were a woman with myxoid mammary fibroadenomatosis and a left atrial myxoma, her daughter who developed a prolactin-secreting pituitary adenoma, and her son who had bilateral large-cell calcified Sertoli cell testicular tumours, and an axillary psammomatous melanotic schwannoma.
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The expression of surface-bound immunoglobulin E by dendritic cells within cutaneous tissue has been compared in atopic and contact dermatitis. 45 patients were recruited into 4 groups using clinical criteria and patch testing to a standard series of allergens: atopic (12 cases), allergic contact dermatitis (14 cases), irritant contact dermatitis (10 cases) and the control group (9 cases); using clinical criteria and patch testing to a standard series of allergens. Skin biopsies from each patient were analysed by the indirect immunofluorescence technique. This differentiated 3 patterns of cutaneous IgE distribution: (i) no detectable cutaneous IgE; (ii) detection of IgE solely within the dermis; (iii) detection of IgE within both epidermis and dermis. Detection of IgE within the epidermis was always associated with the presence of IgE within the dermis. In each case, IgE was surface-bound by dendritic cells. Immunoglobulin E was detected within both epidermis and dermis in skin biopsies from 8 (66.7%) atopic patients and 2 (20%) patients with irritant contact dermatitis. No other cases demonstrated IgE deposition within both the epidermis and dermis. Atopic patients were significantly more likely to have detectable IgE deposition, within both epidermis and dermis, than patients with contact dermatitis (allergic and irritant groups combined, p = 0.0011) or controls (p = 0.0049). This finding suggests that the demonstration of IgE within both epidermis and dermis supports a diagnosis of atopic dermatitis. It would therefore be of value in differentiating between atopic and contact dermatitis, where clinical diagnosis is in doubt.
Transitional employment training is a promising method for assisting persons with mental retardation to gain and hold regular marketplace jobs. The Social Security Administration (SSA) has concluded a large scale demonstration project in which this training was provided to recipients of Supplemental Security Income (SSI) with mental retardation. This article introduces the concepts and practices of transitional employment and presents findings of the SSA demonstration derived from observation of demonstration operations. A followup article will discuss the effects of the demonstration services on the employment, earnings, and SSI payments of the trainees, as derived from analysis of SSI administrative records and other quantitative data.
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Eight volunteers inhaled isoflurane in concentrations of 0.1, 0.2 and 0.4 MAC, and 100% oxygen as control in separate sessions more than 1 week apart. When the end-expiratory isoflurane concentration was stable, response to verbal commands was tested, and the subjects were read 30 words in two lists. Response to the commands was impaired at 0.1 MAC in three subjects and lost at 0.2 MAC in two subjects. No subject responded at 0.4 MAC. When the subjects were questioned 1 h after exposure, memory of response to commands was lost also at these concentrations. Frequently, those who responded to the command "open your eyes" failed to remember having done so; non-responders remembered nothing. At the time of that test, at 0.4 MAC, five of eight subjects had no eyelash reflex. Both recall and recognition of neutral words was lost at 0.2 MAC and greater, but the effect of attention was demonstrated by the memory of a "shock" word by four of eight subjects at 0.2 MAC.
The preliminary results of a trial to examine and compare the safety, tolerability and efficacy of a single dose of teicoplanin with three doses of cephradine combined with metronidazole are presented in a series of 113 patients undergoing elective vascular surgery. There were no obvious differences in the infection rates and sepsis indicators in either group. Neither drug regimen produced any evidence of renal or hepatic damage, though the levels of three hepatocellular enzymes, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl-transferase (GGT), were seen to be transiently elevated, peaking 7 days post-operatively. The trial continues.
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Previous studies showing graded changes in the early cortical waves Pa and Nb of the auditory evoked response (AER) with increasing concentration of volatile anaesthetic agents demonstrated high amplitudes of these waves in the period immediately following induction of anaesthesia and tracheal intubation, when the patient breathed nitrous oxide alone. These high amplitude waves were not consistent with extrapolation of the data or observations of patients under steady-state nitrous oxide anaesthesia. In order to discriminate between effects in the period immediately following induction of anaesthesia and tracheal intubation, and effects caused by nitrous oxide alone, a randomized cross-over study was performed. Eight patients breathed either nitrous oxide or isoflurane at 0.6 MAC for three consecutive 10-min periods following intubation and before surgery. The amplitudes of Pa and Nb were significantly less for isoflurane with respect to the same MAC fraction of nitrous oxide in all periods, but for both agents the amplitudes were significantly greater in the 10 min following intubation than in subsequent periods, presumably as a result of stimulation.
The latency of the early cortical wave Nb of the auditory evoked response (AER) was compared with responses to Tunstall's isolated forearm test, while the concentration of nitrous oxide was progressively reduced during light anaesthesia in seven patients. A threshold Nb latency of 44.5 ms was chosen to discriminate between an early cortical AER containing three waves and that with two waves of longer latency. When Nb latency decreased below this threshold, four of the patients has positive responses, indicating awareness. The addition of a volatile anaesthetic abolished any response, and increased Nb latency to more than 44.5 ms. The three wave AER pattern, therefore, is associated with a depth of anaesthesia at which awareness occurs.
Six patients were anaesthetized with 70% nitrous oxide in oxygen supplemented by infusion of propofol 40, 80, 120, 160 and 200 micrograms kg-1 min-1 sequentially in successive 10-min periods. Auditory evoked response (AER) and lower oesophageal contractility (LOC) were monitored. The AER findings were consistent with those noted in previous studies of i.v. agents. Early cortical waves showed attenuation of Pa and Nb amplitude (P less than 0.01) and increase in Pa and Nb latency (P less than 0.01; P less than 0.05) with increasing blood concentrations of propofol. Brainstem waves were not affected significantly. LOC, provoked and spontaneous, showed no consistent relationship with blood concentration of propofol. The two variables AER and LOC were not related.
Previous studies have shown a dose-related effect of a number of general anaesthetic agents on the early cortical waves in the auditory evoked response (AER). In this study the effect of surgical stimulation on these waves was examined in 11 patients anaesthetized with thiopentone, nitrous oxide and halothane and paralysed with pancuronium. The inspired nitrous oxide concentration and end-tidal halothane concentration were held constant at 70% and 0.3%, respectively, and baseline AER recordings were made. Following surgical stimulation there was a progressive and significant increase in the amplitude of waves Nb and Pb/Pc. Unambiguous autonomic responses were seen in three patients, but these were not significantly correlated with changes in the AER. We conclude from this, and previous studies, that the amplitude of cortical waves in the AER are sensitive not only to anaesthetic concentration but also to surgical stimulation. The AER may, therefore, provide a useful index of depth of anaesthesia, that is the balance between the effects of surgical stimulation and anaesthetic depression on central nervous system activity.
Expanded community care for the frail elderly has been advocated based on its potential for financial cost saving. However, the evaluation found that average costs increased: the cost of expanding publicly financed case management and formal community services beyond what already was provided was not offset by reductions in the costs for nursing home care.
We have examined the effects of isoflurane (0.6-2.9% end-tidal) on the auditory evoked response (AER) in six patients before elective surgery. Isoflurane produced significant dose-related changes in the AER: reductions in amplitude and increases in latency of the cortical waves Pa and Nb, and increases in the latency of the brainstem waves III and V. When isoflurane was compared with halothane and enflurane using an MAC-based comparison, we found no differences in the effect of the three agents on the amplitude of the early cortical waves, although the latencies showed significant differences. The consistent dose-related effect on the amplitudes of the cortical waves implies that the AER could be a promising index of the depth of anaesthesia.