Hypothermia associated with extensive hysteroscopic surgery.
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Adult↗
Biomedical subjects
R Richardson
Publications and source records attributed to R Richardson.
Married to a nurse.
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Adaptation, Psychological↗
Reactivation of nonassociative memory.
The orienting response to an auditory stimulus, as measured by a decrease in heart rate, habituates rapidly, and at the same rate in preweanling and adult rats. Although adult rats retain this nonassociative memory for at least 7 days, preweanling rats show extremely rapid forgetting. In the preweanling, forgetting of this nonassociative memory appears to be complete after just 24 hr (Richardson & Campbell, 1991b). The results of several experiments in the present study with preweanling rats demonstrated that this type of nonassociative memory could be reactivated by presenting a fractional component of the original eliciting stimulus just prior to testing. The effectiveness of the reactivation treatment was critically dependent upon both the number of reactivating stimuli presented and the duration of those stimuli. Reactivation was also found to be stimulus-specific in that presentation of an auditory stimulus qualitatively different from that used in training (white noise instead of a pure tone) did not reactivate the memory. Control groups in each experiment demonstrated that the reactivation treatment facilitated retrieval of the prior nonassociative memory and did not produce new learning. A possible process through which nonassociative memories can be reactivated is discussed.
Animals↗
Audit of nutritional support provided to surgical patients by a nutrition team.
An audit was carried out over a 24 month period to assess the practice, safety and efficacy of nutritional support provided to surgical patients by a designated team. 135 patients received nutritional support: 51% were fed parenterally, 32% enterally and 17% via combined nutritional support. The duration of feeding ranged from 1-177 days with 23% being supported for < 7 days. The line infection rate for patients receiving intravenous nutrition was 6.5%. Nutritional outcome was assessed using weight, anthropometry and bioelectrical impedance analysis. Pre-and post-feeding results were available for 67% of patients. These patients were classified as either oedematous (n = 21), normally nourished (n = 23) or nutritionally depleted (n = 46). Overall, the oedematous patients lost water, the protein status of the normally nourished group deteriorated slightly and the nutritional status of the nutritionally depleted patients was maintained. Audit is a valuable means of defining the efficacy of a nutrition support service and has identified areas which require review.
Journal Article↗
Extrarenal effect of cyclosporine A on potassium homeostasis in renal transplant recipients.
Cyclosporine A (CyA) is known to cause hyperkalemia by impairing renal potassium excretion. However, the observation of transient and severe hyperkalemia occurring within 3 to 5 hours of CyA ingestion in several organ transplant patients led us to postulate that it might also cause a potassium efflux from the intracellular to the extracellular fluid space. We tested this hypothesis by studying 22 nondiabetic, renal transplant patients with stable renal function (serum creatine < 2.25 mg/dL) who were treated with CyA (CyA group; n = 14) or imuran and prednisone (STD group; n = 8). Eight CyA and four STD patients also were treated with a beta-blocker (BB). While at rest, fasting plasma potassium levels were sampled hourly in all patients from 8:00 am to 1:00 pm. All medications (including CyA and BBs) were given after the 8:00 am blood sampling. Venous pH, osmolality, insulin, aldosterone, epinephrine, norepinephrine, and CyA levels also were determined at 8:00 am, 11:00 am, and 1:00 pm. Urine was collected from 11:00 pm to 8:00 am prior to the study (period I) and from 8:00 am to 1:00 pm during the study (period II) for measurement of potassium excretion (standardized to a 5-hour period). A significant increase in serial plasma potassium levels was noted in the CyA + BB group only (P = 0.0006 by repeated measures analysis of variance).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
A Monte Carlo model for retrospective analysis of shield design in a diagnostic x-ray room.
Recent recommendations by the NCRP and the ICRP have lowered the nonoccupational dose limit from 5 mSv y-1 to 1 mSv y-1 [corrected]. This change has also been incorporated in the recently revised Title 10 Code of Federal Regulations, Part 20. Shielding installed in most current diagnostic x-ray rooms was based on the 5-mSv limit when rooms or corridors adjacent to the x-ray room were unrestricted areas. A computer model for evaluating shielding in a diagnostic x-ray room has been developed using the following: the Monte Carlo Code MCNP, all materials that would normally attenuate the beam in an x-ray room, realistic assumptions for work load, and a spectrum of tube potentials based on actual usage. Results indicate that most radiographic x-ray rooms with shielding designed using the conservative assumptions in NCRP 49 will meet the new standards.
Evaluation Studies as Topic↗
Muscular strength capacity and altitude response.
To determine the relationship between muscular strength and altitude response, two groups of 7 and 8 subjects were selected from 40 healthy male volunteers, as either high-strength (HS) or low-strength (LS) by performance on a battery of strength tests. There was no difference in hypoxic ventilatory response (HVR) between groups at normobaria. The 4 h hypobaric conditions in a Hypo-hyperbaric Chamber (PBar = 429) produced qualitatively similar altitude-induced physiological responses. However, the LS group showed a lower SaO2 at 2 and 4 h of hypoxia (p < 0.05). Furthermore, PETCO2 and PVCO2 were lower and PETO2, PVO2, and pH were greater in the HS group during hypobaria, although these differences did not achieve statistical significance. Muscular strength index (body weight divided by strength test values) was negatively correlated with PvCO2 (r = -0.63, p = 0.0074), PETCO2 (r = -0.62, p = 0.006) and positively with SaO2 (r = 0.54, p = 0.018) at altitude. These findings suggest that the HS group may have become more hypocapnic and alkalotic (suggesting a greater ventilatory response), and consequently less hypoxic than the LS group.
Adult↗
Management of patients with the Zollinger-Ellison syndrome.
The Zollinger-Ellison syndrome, which is due to the secretion of gastrin from non-beta islet cell tumors of the pancreas, results in gastric hypersecretion and severe peptic ulcer disease. In the 1970s H2 blockers became the mainstay of therapy. More recent evidence indicates that early surgical intervention aimed at tumor extirpation results in improved outcome. The purpose of this paper is to report the case histories of three patients with Zollinger-Ellison syndrome and to review the current literature on management of patients with this syndrome.
Adult↗
Developmental constraints on the expression of behavioral and heart-rate orienting responses: II. The role of ambient temperature.
The effect of ambient temperature on the expression of behavioral and heart-rate orienting responses to a novel olfactory stimulus was examined in rats 1-18 days of age. There was no effect of ambient temperature on the behavioral orienting responses at any age. Ambient temperature did influence the expression of the heart-rate orienting response and did so differentially as a function of age. The implications of these findings for developmental models of attention and cognition are discussed.
Animals↗
Emergency center arteriography.
From 1983 through 1989, 1,882 emergency center arteriograms were performed on 1,802 patients suspected of having peripheral vascular injuries. The most common indication for emergency center arteriography (ECA) was the proximity of an injury to a major vascular structure. This was the only indication in 1,712 injured extremities (91%). There were 1,510 true negative arteriograms, 294 true positives, 7 false negatives, and 14 false positives. Accordingly, the sensitivity was 95.5% and the specificity was 97.7%. The remaining 57 arteriograms were either equivocal or technically inadequate. Further evaluation of these patients uncovered an additional 11 vascular injuries. Operative intervention was required for 196 (64.3%) injuries detected by emergency arteriography. The remaining 109 injuries were considered minor and were not repaired. No complications developed in 91 patients (88%) with minor vascular injuries who were available for a mean follow-up duration of 12 months. One thousand forty-eight patients (69.4%) with negative arteriograms were followed for a mean of 18 months, and no vascular complications were noted. Emergency center arteriography is a rapid, accurate, and cost-effective technique. It is of particular value in detecting the presence of occult arterial injuries when proximity of a major vascular structure is the sole indication for arteriography. When formal arteriographic support is either unavailable or time consuming, ECA is recommended.
Adolescent↗
Neurologic consequences of cerebrovascular injury.
Because of ongoing controversy, the issue of vascular repair or ligation for patients with cerebrovascular injuries and preoperative central neurologic deficits is frequently debated. A total of 133 patients with penetrating cerebrovascular injuries were analyzed. The frequency of preoperative neurologic deficit was 20% (27 patients). The common carotid and internal carotid arteries were the most frequently injured structures, with a 29% and 15% incidence of preoperative neurologic deficits, respectively. The results of carotid repair in all patients whose preoperative deficit was limited to weakness or paralysis were favorable (seven patients normal or improved, two patients unchanged). The results of repair in patients whose preoperative deficit was characterized by obtundation were variable (four patients improved, four patients worsened or died). The results of carotid ligation were also variable (one improved, one unchanged, three worsened or died). Limited numbers of patients with preoperative neurologic deficits and the retrospective nature of this review prohibit definite conclusions. Therefore a multicenter, prospective, randomized trial of ligation or vascular repair for comatose patients with cerebrovascular injuries is proposed.
Carotid Artery Injuries↗
Developmental changes in the duration of attention to unfamiliar stimuli in the rat.
The purpose of the present study was to examine developmental changes in the duration of attention to novel auditory stimuli in rats from infancy to adulthood. In all experiments, the cardiac component of the orienting response was used as the index of attention. In the first experiment 16-, 23-, 30-, and 75-day-old rats were exposed to a novel auditory stimulus for 60 s. Animals of all four ages exhibited a marked decrease in heart rate in response to this stimulus. Although there were no significant effects of age on the magnitude of the cardiac response, there were dramatic developmental differences in the persistence of the response. The 16-day-olds maintained a decrease in heart rate for the entire stimulus period, whereas heart rate returned to baseline in the 75-day-olds after only 40 s. The duration of the cardiac response of the 23- and 30-day-olds was between these extremes. In Experiments 2A and 2B the effect of stimulus complexity on duration of the cardiac response was examined. Increasing stimulus complexity prolonged the deceleratory response in the 30-day-olds (Experiment 2A), and decreasing stimulus complexity decreased the duration of the cardiac response in the 16-day-olds (Experiment 2B). The results of these experiments were discussed in the context of Cohen's and Porges's two-phase theories of attention. The findings demonstrate that the initial attention-getting or reactive phase of attention did not change with age, but that the duration of the attention-holding or sustained phase decreased substantially during development.
Acoustic Stimulation↗
The multiple choice true/false question: what does it measure and what could it measure?
Multiple choice questions of the true/false type are widely used in medical education. Evidence is given which suggests that they only tap a low level of intellectual skill. By using them in a slightly different manner it is suggested that they could be ideal techniques for measuring concept mastery. Some of the consequences of this idea are discussed.
Education, Medical, Undergraduate↗
Effects of cardiac surgery and intraoperative hypothermia on energy expenditure as measured by doubly labelled water.
Total energy expenditure (TEE) was measured over two 10-day periods, before and after operation in 16 patients undergoing coronary artery surgery and randomized to have cardiopulmonary bypass with an intraoperative blood temperature of either 28 or 20 degrees C. TEE was measured with doubly labelled water containing stable isotopes of hydrogen and oxygen to allow calculation of TEE over fixed periods from the differential rate of excretion of the two isotopes. Results were available for eight patients in the 28 degrees C group but for only seven in the 20 degrees C group (one patient in this group was excluded as the temperature allocated was not achieved). The groups were similar with respect to body-weight and lean body mass. The 20 degrees C group received more grafts than the 28 degrees C group, resulting in an increase in cross-clamp and bypass times. Mean preoperative TEE was similar in both groups. The mean difference in fractional turnover rates of hydrogen and oxygen was not significantly different in the postoperative period. There was a non-significant increase in the mean 10-day postoperative TEE, calculated in total calories, of 4.7 per cent in the 28 degrees C and 5.1 per cent in the 20 degrees C group. When changes in postoperative TEE were calculated according to lean body mass, the mean increases were respectively 3.7 and 3.2 per cent. Cardiac surgery utilizing cardiopulmonary bypass and intraoperative hypothermia results in only a modest increase in postoperative TEE. In this study a more profound level of intraoperative hypothermia did not influence the change in postoperative TEE.
Adult↗
Developmental constraints on the expression of behavioral and heart-rate orienting responses: I. The role of cardiosomatic coupling.
The ontogeny of behavioral and heart-rate orienting responses to a novel olfactory stimulus was examined in three experiments. The results of Experiment 1 demonstrated that behavioral responses to the olfactory stimulus were observed as early as Day 1, although heart-rate deceleration in response to the stimulus was not observed until Day 9. In Experiment 2, bradycardia was observed in 6-day-old pups if stimulus-elicited motor activity was reduced with haloperidol. Thus, the developmental asynchrony in the expression of behavioral and heart-rate orienting responses was due, at least in part, to cardiosomatic coupling in the very young animal. The results of Experiment 3 demonstrated that although cardiosomatic coupling interferes with the expression of the heart-rate orienting response very early in development, it has increasingly less impact over the course of the preweaning period.
Aging↗
Outcome for delayed operation of penetrating colon injuries.
It has been stated that delay in operative repair of penetrating injuries to the gastrointestinal tract will result in a high rate of complications related to infection. To test this assertion, a group of patients with penetrating injuries to the colon were analyzed who had operative repair delayed (usually because of triage considerations) more than 6 hours after admission to the hospital. Nine hundred six patients who survived at least 48 hours after injury were divided into two groups. The immediate group of 769 patients was treated within 6 hours of admission and the delayed group of 137 patients was treated more than 6 hours after admission. The mortality for the immediate group was 4.0% vs. 1.5% for the delayed group. Colon-related infectious complications, defined as abscess or colon suture-line failure, occurred in 10% of the immediate group and 4.4% of the delayed group. To eliminate the effect of associated injuries, the group of patients with colon injuries only was analyzed separately. There was no mortality for 128 patients with colon injuries only operated on within 12 hours of injury, and the colon-related infectious morbidity rate was 3%. Eleven patients with colon injuries only were treated after 12 hours with a mortality of 9% and colon-related infectious morbidity of 18%. These data demonstrate that even patients with fecal contamination can have operative repair delayed for up to 12 hours without undue morbidity related to infection.
Adult↗
Somnambulism, vampirism and suicide: the life of Dr John Polidori.
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Death↗
Effects of four beta-adrenergic receptor antagonists on male rat sexual behavior.
Antihypertensive medication has been reported to cause serious sexual side effects in men. Frequently mentioned as causing sexual dysfunction are beta-adrenergic receptor antagonists. The purpose of this study was to examine in detail the effects of beta blockers on adult male rat sexual behavior. Thirty minutes following a single subcutaneous injection of propranolol, pindolol, atenolol or labetalol, mating tests were conducted. The mixed beta 1- and beta 2-adrenergic antagonists, propranolol and pindolol, profoundly inhibited male sexual behavior. At the 5 and 10 mg/kg doses, propranolol inhibited ejaculatory behavior to the extent that only 9.1 and 8.3% respectively showed the behavior while pindolol reduced this behavior to 36.4% (16 mg/kg). These drugs also adversely affected various parameters of behavior in a dose-dependent manner. The selective beta 1 antagonist, atenolol, had only minor effects and labetalol even less so at the doses tested. It was suggested that the strongly inhibitory effects of propranolol and pindolol on male rat sex behavior may well be due to their 5-HT1A antagonistic binding properties rather than their beta-antagonistic properties.
Adrenergic beta-Antagonists↗