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Biomedical subjects

S Porter

Publications and source records attributed to S Porter.

At least 109 records · Page 6Linked to original sources
PubMed1996

Simple motor tics may be preceded by a premotor potential.

Obeso et al reported that simple motor tics in Tourette's syndrome were not associated with premotor potentials, which were present when patients mimicked their tics voluntarily, suggesting that spontaneous tics were not generated in the same manner as voluntary movements. Five patients with simple motor tics were studied using a similar paradigm. Premotor potentials were examined during spontaneous tics and during voluntary imitation of the tics. All patients had premotor negativity with the voluntary movements. As in the study of Obeso et al, spontaneous tics were not preceded by premotor potentials in three patients. However, premotor negativity was present with spontaneous tics in two patients and resembled the NS' segment of the premotor potential seen with self paced, voluntary movements. A similar premotor potential pattern has been reported with voluntary movements performed in response to external triggering stimuli. In patients with Tourette's syndrome, the eliciting signals could be internal sensations.

Adult↗
PubMed1995

Delayed neuropathy in pigs induced by isofenphos.

In 1990 an outbreak of ataxia occurred in over 700 pigs in the north of England. Epidemiological studies demonstrated that the disorder was associated with the consumption of feed from a particular supplier and that one component (wheat screenings) was common to the batch of feed with which the ataxia was associated. An analysis of the feed demonstrated the presence of an organophosphorus pesticide, later identified as isofenphos, a pesticide not approved for use in the United Kingdom. The wheat screenings had been imported from France and the warehouse in which they had been stored was contaminated with isofenphos, which is approved for restricted use in France. Isofenphos is known to cause delayed neuropathy. The dose to which the pigs were theoretically exposed would be expected to have resulted in neuropathy (manifested as ataxia).

Acetylcholinesterase↗
PubMed1995

A comparison of the eyewitness accounts of deaf and hearing children.

Children with hearing impairments have been found to suffer a high rate of physical and sexual victimization relative to children in general. The purpose of this investigation was to compare the amount and accuracy of the information contained in the eyewitness accounts of deaf and hearing children. Fifteen deaf and 11 hearing children, aged 8 to 10 years, individually witnessed a series of slides depicting a wallet theft. Their recall was then tested by using the Step-Wise Interview (Yuille, Hunter, Joffe, & Zaparniuk, 1993) consisting of a free recall component followed by increasingly directive questions. Separate 2 x 2 (deaf/hearing x question type) between-within factorial ANOVAs were conducted on the amount and accuracy of the information in the accounts (A = .025). Results indicated no main or interaction effects for amount recalled. However, a main effect for question type and an interaction effect were evidenced in the analysis on accuracy. Although the accuracy scores of the two groups did not differ in free recall, the deaf children provided much less accurate responses to directive questions whereas the accuracy of the hearing children declined only slightly. Implications for criminal investigations are discussed.

Child↗
PubMed1995

Sociology and the nursing curriculum: a defence.

This paper is a response to Keith Sharp's (1994) argument in the Journal of Advanced Nursing that sociology cannot in principle provide a knowledge base for nursing work. The aim here is to reassert the appropriateness of including sociology in the nursing curriculum. Three arguments put forward by Sharp are engaged with. First, he questions nursing's need for any theoretical basis at all. This hypothesis is rejected on the grounds that any occupation that is involved in complex decision-making requires some sort of theoretical guidance. Second, Sharp argues that the multi-paradigmatic nature of sociology makes it inappropriate for nurses who require more certain knowledge as a basis for their actions. Two responses to this argument are made: first, that the fissures within sociology are not as great as Sharp portrays them and, second, that nurses possess adequate criteria to be able to judge between different sociological propositions. Sharp's final argument is that the reflexive approach of sociology is an inappropriate way of thinking for nurses, whose approach is instrumental. In reply, it is noted that Sharp's instrumental model of nursing action does not adequately reflect the manner in which nurses interact with patients, and that 'new nursing' practices require reflexivity on the part of the nurse.

Curriculum↗
PubMed1995

Rat mesothelial and tracheal epithelial cells show equal DNA sensitivity to hydrogen peroxide-induced oxidant injury.

To study the relative sensitivity of rat tracheal epithelial and mesothelial cell DNA to oxidant damage, we used the comet assay, a gel microelectrophoresis method that allows visual determination of DNA strand breaks on a cell-by-cell basis, to evaluate damage after hydrogen peroxide exposure. By both a qualitative and a quantitative assay, tracheal epithelial mesothelial cells demonstrated a similar dose-response increase in the number of cells showing strand breaks and the number of breaks per cell after exposure to increasing concentrations of hydrogen peroxide; but even at the highest concentration, some cells failed to show damage. By contrast, 100% of cultured V79 lung fibroblasts showed evidence of damage. Catalase and deferoxamine largely prevented the formation of strand breaks, while superoxide dismutase was not protective. To evaluate DNA repair, cells were exposed to 10 microM hydrogen peroxide for 10 min, washed, and maintained in culture medium; by 2 h the proportion of mesothelial and epithelial cells showing comets had returned to control levels for both cell types. Both cell types also showed a similar pattern of increasing damage after continuous exposure to 10 microM hydrogen peroxide for periods up to 2 h. We conclude that, in this system, 1) mesothelial and tracheobronchial epithelial cells show a similar pattern of DNA injury and repair after hydrogen peroxide exposure; 2) hydrogen peroxide damages DNA of both cell types via a mechanism probably related to the iron-catalyzed formation of hydroxyl radical; and 3) both types of cells appear to be heterogeneous in their sensitivity to oxidant damage, with some cells showing extreme resistance to such damage.

Animals↗
PubMed1994

The effects of programmed ventricular stimulation on plasma procainamide levels: an experimental model.

To evaluate the effects of programmed ventricular stimulation on resultant plasma concentrations of intravenously administered procainamide, drug dosing was performed with and without ventricular stimulation on two separate days (48 hours apart) in 12 dogs (13 dosing trials) at > or = 14 days after myocardial infarction (mean: 62 days). During infarct surgery, three bipolar electrodes were plunged into left ventricular epicardium, externalized, and later used for ventricular stimulation. On the first study day, procainamide was dosed to achieve two sequential plateau plasma levels (I and II), with a 20-minute equilibrium period at each plateau before ventricular stimulation. Plasma procainamide concentrations were measured before initiation of ventricular stimulation and at the completion of ventricular stimulation for each sequential plateau level. Stimulation involved delivery of one, two, and three extrastimuli at three paced cycle lengths at three left ventricular sites before procainamide dosing and at each of the two procainamide plateau levels. Three dogs were excluded from analysis due to induction of lethal ventricular arrhythmias. No ventricular arrhythmias were induced in the remaining nine animals. On the second study day, procainamide was dosed identically, but no ventricular stimulation was performed. Intravenous drug administration and collection of plasma concentration samples were performed with +/- 1 minute on both study days. Mean plasma procainamide concentrations at the end of ventricular stimulation at dosage Levels I & II were 10% and 12% greater (P < 0.02 and P < 0.005, respectively) than plasma concentrations measured at comparable times on the study day when no ventricular stimulation was performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Viral hepatitis. Current concepts for dental practice.

The transmission of blood-borne viruses in the dental office is a potential hazard to patients and dental staff, particularly to oral and maxillofacial surgeons. Hepatitis B virus has been a recognized hazard for several years, and in the past oral surgeons and other dental health care staff have been infected as a result of occupational exposure. Hepatitis C virus in contrast does not appear to be a major occupational hazard to dental staff, nevertheless, infection with this virus can lead to significant morbidity and may have oral manifestations. Hepatitis D virus can be nosocomally transmitted, but vaccination against the hepatitis B virus minimizes this problem. Hepatitis E virus is not of clinical relevance to dentistry, although dental staff who are in areas of endemic infection can become infected as a result of enteric transmission. A number of other putative viral agents may also cause hepatitis, but additional data is awaited, and their significance to dental practice is unknown. This article summarizes current data on hepatitis viruses A, B, C, D, and E.

Blood-Borne Pathogens↗
PubMed1994

An introduction to nonavian wildlife emergencies.

This article lists some basic guidelines for practitioners to use in treating wildlife patients. Major issues associated with wildlife practice are introduced. Important sources of equipment and major literature are contained in appendices.

Anesthesia↗
PubMed1994

Confirmation of sulfonamide residues in kidney tissue by liquid chromatography-mass spectrometry.

The development of a method to confirm the presence of sulfonamide residues in kidney tissues at levels at or above the maximum residue limit (MRL, 100 ng g-1 total sulfonamide) using a tandem mass spectrometer [i.e., mass spectrometry-mass spectrometry (MS-MS)] interfaced to a high-performance liquid chromatography is described. Although sulfonamides can be determined using a single quadrupole mass spectrometer with pseudo-MS-MS, advantages in interfacing to a tandem mass spectrometer are demonstrated.

Abattoirs↗
PubMed1994

New nursing: the road to freedom?

The consequences that recent developments in nursing have had for the nurse-patient relationship are the concern of this paper. It is argued that, by attempting to reduce the power differentials that exist between nurse and patient, 'new nursing' reforms encourage rational, rather than distorted, communication between lay and professional participants in health care encounters. The significance of these developments is underlined by framing them within the theoretical framework developed by Jürgen Habermas, who argues that, because symbolic communication is a defining feature of our essential humanity, distortion of communication by means of coercive power is a denial of that humanity. Conversely, rational communication is the stuff of truth, freedom and justice. Empirical evidence from in-depth interviews with nurses is used to demonstrate that there have been significant changes in the nurse-patient relationship, which have led to improvements in communication and to the empowerment of patients. Despite the fact that the reforms face significant obstacles, nurses can be proud of the fact that their efforts have contributed to the re-affirmation of the full humanity of people requiring health care.

Communication↗
PubMed1994

Views of dental patients about the education and practice of dentists.

The opinions of 253 adult U.K. dental patients were sought as to the scope of dental education. Most appreciated this was a university education and that it exceeded 3 yr. Nearly one half believed that apprenticeship was involved and one quarter believed that postgraduate experience in hospital was mandatory. Few acknowledged the wide breadth of training and a majority would consult a physician rather than a dentist regarding problems such as oral ulceration.

Adolescent↗
PubMed1993

Urinary growth hormone measurements as a marker of renal tubular function in diabetes mellitus.

Urinary growth hormone (UGH) excretion was assessed in 44 adult subjects (10 control, 21 insulin dependent diabetics (Group I), 13 diabetics in poor glycaemic control (Group II)). UGH was markedly elevated in the diabetic population. The UGH excretion in (1) control subjects ranged from undetectable levels to 0.7 microU/h, mean 0.4, (2) Group I 73-422 microU/h, mean 250 and (3) Group II 10-5,283 microU/h, mean 705. There was a significant correlation between UGH excretion and albumin excretion rate (AER) (r = 0.38, P < 0.05) in the subjects studied although only 50% of patients had an AER of > 20 micrograms/min. A stronger correlation was observed between beta 2-microglobulin and UGH excretion (r = 0.7, P < 0.01). There was no significant change in the 6-h serum GH levels following treatment in the patients in Group II. However a 23-79% decline in UGH excretion was observed following improvement of glycaemic control, although UGH levels failed to revert to normal. We conclude that the major factor responsible for increased UGH excretion in DM appears to be reduced tubular reabsorption of the hormone. This test may therefore prove useful as an additional marker for screening for diabetic nephropathy and may help in the understanding of the contribution of renal tubular abnormalities to the nephropathic process.

Adult↗