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Biomedical subjects

S Walsh

Publications and source records attributed to S Walsh.

At least 145 records · Page 8Linked to original sources
PubMed1988

Two methods of ligament injury: a morphological comparison in a rabbit model.

Our purpose in this study was to compare morphologically the reproducibility and control of two common methods of ligament injury. Polarized light and scanning electron microscopy were used to quantify the injury patterns and the extent of ligament damage caused by scalpel division and wire rupture of rabbit medial collateral ligaments. Results demonstrate that the scalpel cut and wire rupture methods of ligament injury are each controllable and reproducible in location, pattern, and extent of ligament damage. The wire rupture technique, however, produced consistently more extensive midsubstance ligament damage than the scalpel cut and thus created an injury pattern that better simulated the extent of damage seen in clinical injuries. Although neither technique was an ideal simulation of clinical injuries, results suggest that the wire rupture technique is a more relevant technique to study ligament injury and healing in this model.

Animals↗
PubMed1988

Equatorial potassium currents in lenses.

Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K+ concentrations across the membrane responsible for J is unchanged. Therefore, the decrease in PD is ascribed to an increase in Na+ permeance with a resultant increase in driving force accounting for the increase in J.

Animals↗
PubMed1988

The use of hospital beds for terminally ill cancer patients.

A study to identify reasons for admitting terminally ill cancer patients to hospital is reported together with recommendations for the future. Forty per cent of patients were so seriously ill with pain, medical or nursing problems that their carers could not manage satisfactorily at home and hospitalisation was necessary and appropriate. In addition 27% of patients admitted had no family or carers to nurse them at home. In the remaining 33% of patients it may have been possible with planned admissions and better supportive communications to allow some patients to die at home. Analysis of the data would suggest that there are three principal reasons for continuing to provide hospital beds for the terminally ill cancer patient: 1. Special medical and nursing care. 2. To provide care for some patients with no family or friend carer support. 3. Teaching of management by senior staff. The unsatisfactory nature of terminally ill patients dying in the centre of acute wards together with inadequate facilities to interview relatives is noted. It is suggested that the provision of well planned hospital beds is more appropriate than providing remote hospice beds for the terminally ill cancer patient.

Hospitals↗
PubMed1988

Effect of ouabain on lens equatorial currents.

The equatorial potassium current measured with the vibrating probe is a segment of the potassium electrical loop. The equatorial current, J, was measured simultaneously with the PD and with the response to an injected current, I. The injection of sufficient inward current, I, made the PD more negative and increased the electrical gradient so that the current J became zero. The PD at which this occurs (PDJ-0) is the reversal potential. Following treatment with ouabain, the PD and PDJ-0 both become less negative. Since the driving force for the current, J, is equal to the difference between PD and PDJ-0, J may increase, stay the same or decrease depending on the relative changes in PD and PDJ-0. In the presence of ouabain, the PDJ-0 changes in parallel with or more rapidly than the PD.

Animals↗
PubMed1986

Young children's understanding of smoking.

32 children aged 7-8 years and 30 children aged 10-11 years were interviewed individually about their knowledge and beliefs about the physiological and social effects of smoking. Knowledge about the consequences of smoking in terms of vulnerability to disease and damage to the body increased with age but was high for both groups. Most striking was the increase with age in children's awareness that smoking could be used to control negative mood states rather than simply result in positive enjoyment. The data attest to much social, rather than purely cognitive learning, of beliefs about smoking among children.

Attitude to Health↗
PubMed1982

Studies of chemically modified honeybee venom. I. Biochemical, toxicologic and immunologic characterization.

Allergens of honeybee venom (BV) were modified by formaldehyde treatment (F), acetoacetylation (A) or coupling to polyethylene glycol (P). The biochemical, toxicologic and immunologic properties of these modified BV preparations were analyzed. F showed strongly reduced cytotoxicity, enzymatic activity and reactivity with human BV-specific IgE antibodies but retained the reactivity to BV-specific human and rabbit IgG. In A, enzymatic activity, cytotoxicity and the reactivity with human IgE and rabbit IgG antibodies were only moderately reduced. P lacked enzymatic activity and cytotoxicity and showed only minimal reactivity with IgE and IgG antibodies to BV.

Acetoacetates↗
PubMed1981

Comparison of vespid venoms collected by electrostimulation and by venom sac extraction.

Venoms of three vespid species, yellow jacket, bald-faced hornet, and yellow hornet, obtained by either electrostimulation of venom sac extraction were compared with regard to their enzymatic activity, antigenicity, and allergenicity. Phospholipase a, phospholipase B, and hyaluronidase enzymatic activities were present in all six preparations. The activity of venom sac extracts lay in the range found in different batches of venoms obtained by electrostimulation for each species. Analysis of sera from vespid-sensitive patients in the radioallergosorbent test (RAST) with discs coupled with either venom sac extracts or venoms obtained by electrostimulation showed a good correlation of the results within all three species (r = 0.95). In RAST inhibition the potency of venom sac extracts and venom obtained by electrostimulation was similar for each species. Analysis of rabbit antisera to the six preparations revealed similar patterns in immunoelectrophoresis and identity reactions between the major antigens within each species. Tissue protein contamination was detected in all venom sac extracts but not in venoms obtained by electrostimulation.

Animals↗
PubMed1981

Virus-induced alterations in insulin release in hamster islets of Langerhans.

After the inoculation of Golden Syrian hamsters with the TC-83 vaccine strain of Venezuelan encephalitis (VE) virus, a sustained diminution in glucose-stimulated insulin release and glucose intolerance of shorter duration develops. To understand better the mechanism of this defect in insulin release, we examined insulin secretion in response to several test agents in isolated perifused islets from control and 24-d post-VE virus-infected hamsters. 50 islets were used in all perifusion experiments, and data were expressed as total insulin released as well as peak response for each test agent during a 30-min perifusion period from control and VE-infected islets. After perifusion with 20 mM glucose, a 45% diminution of insulin release was noted in VE-infected islets in comparison with control islets, which in turn was similar to in vivo findings. However, following 1-mM tolbutamide stimulation, insulin release was similar in control and VE-infected islets. In separate studies, 1 mM tolbutamide, 10 mM theophilline, 1 mM dibutyryl cyclic (c)AMP, and 1 mM 8-bromo-cAMP resulted in statistically similar insulin-release curves in control and VE-infected islets. Additional experiments assessing [5-3H]glucose use in control and infected islets after 20 min of perifusion with 20 mM glucose revealed virtually identical values (239 +/- 30-control; and 222 +/- 27-VE-infected islets). Morphological and morphometric evaluation of VE-infected islets (21 d following virus inoculation) showed no changes in islet volume density, beta cell density, and beta cell granulation. Thus, VE virus induces a defect in glucose-stimulated insulin release from hamster beta cells that can be corrected by cAMP analogues and does not alter islet glucose use.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1980

Interobserver and intraobserver reliability in the collection of emergency medical services data.

The collection of data by abstraction from patient records is a widely used method of research, evaluation, and registry. Since valid conclusions depend on the accuracy of the abstracted data, it is essential to examine the abstracting procedures. In this paper, we report on a study of patient data abstracted from emergency department records by nurses trained by project personnel. Twenty-five charts were selected at each of five hospitals. To test interobserver reliability, the nurses were asked to abstract all of the charts at each hospital; to test intraobserver reliability, four of the nurses each reabstracted a set of charts. The results show that even with highly trained, well motivated abstractors, there are considerable differences in the accuracy with which the variables are abstracted. Disposition from the hospital, quantitative vital signs, and blood gas values tend to be abstracted with higher reliability; whereas variables requiring judgment, such as character of vital signs or history of disease, tend to have low reliability. To improve the quality of abstracted data, we propose improved retrieval methods for hospital records, monitoring of data collection procedures, cooperation of all medical personnel providing the raw data, and careful selection of variables.

Emergency Service, Hospital↗
PubMed1979

Protocol for determining the auditory percepts of electrical stimulation of the cochlea.

The percepts of electrical stimulation of the auditory nerve can best be determined in man. An eight channel bipolar electrode array has been developed which allows discreet stimulation of segments of auditory nerve via the scala tympani. In addition, a programmable stimulator has been developed which allows the delivery of different waveforms and stimulus patterns. Hopefully this will begin to allow the generation of the elements of speech.

Animals↗