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Biomedical subjects

C Clinton

Publications and source records attributed to C Clinton.

17 recordsLinked to original sources
PubMed2004

In situ lift-out using a FIB-SEM system.

An in situ 'lift-out' technique for preparing transmission electron microscopy specimens, which is performed using secondary electron imaging within the chamber of a focused ion beam-SEM system is presented. The main advantage of this in situ approach, relative to the ex situ lift-out technique, is that secondary electron imaging enables higher magnifications to be used than is possible with optical microscopy. This makes the lift-out procedure more controllable and thus increases the overall success rate especially for inexperienced users. The technique is also compared with another in situ lift-out approach, the 'wedge' technique.

Journal Article↗
PubMed2000

Effects of changes in cadence, prosthetic componentry, and time on interface pressures and shear stresses of three trans-tibial amputees.

OBJECTIVE: To evaluate the effects of changes in cadence, prosthetic componentry, and time on interface pressures and resultant shear stresses in trans-tibial amputee case studies. DESIGN: Interface stresses were monitored using custom-designed instrumentation at 13 sites on three subjects with unilateral trans-tibial amputation walking with patellar-tendon-bearing prosthetic limbs. BACKGROUND: Previous studies suggested that week-to-week residual limb changes altered interface stresses more than did alterations in prosthetic alignment. No studies investigating effects of changes in cadence or componentry on interface stress distributions nor comparing their influence with week-to-week changes have been conducted previously. METHODS: Five different prosthetic componentry configurations were tested at each of three cadences in four sessions. Data were analysed for the magnitudes and timings of peak pressures and resultant shear stresses as well as corresponding resultant shear angles. RESULTS: None of the three cadences or five componentry configurations consistently induced significantly (P<0.05) higher or lower interface stress magnitudes for all subjects. However, an Aluminium Pylon/SACH Foot combination compared with an AirStance (pneumatic shank)/Seattle LightFoot unit induced later peak interface stress timings as a percentage of stance phase. Higher and more frequent interface stress changes were seen between the weekly sessions than between different cadences or between different componentry configurations. CONCLUSION: The amputees' capabilities to compensate for week-to-week residual limb changes were less than those for intra-session cadence or componentry alterations. RELEVANCE: Results suggest that effective techniques to accommodate week-to-week residual limb fluctuations could have a greater impact on maintaining consistent interface stress distributions than do adjustments in cadence or componentry.

Adult↗
PubMed2000

Changes in interface pressure and stump shape over time: preliminary results from a trans-tibial amputee subject.

Interface stresses and stump shape were measured during sessions over a two-month interval on a trans-tibial amputee subject. Results from thirteen transducer sites monitored during four sessions showed greater interface pressure changes over time at anterior sites than at lateral or posterior locations. There was a trend of decreased pressure with stump swelling and increased pressure for stump atrophy. During one session in which stump shape was monitored over a 23.1 min interval after ambulation, stump swelling was localised. Swelling tended to increase in the regions of initial enlargement, as opposed to redistributing through different areas over time. Regions of swelling were anterior lateral and posterior proximal, areas of thick underlying soft tissue. Identification of localised areas of swelling and atrophy and understanding of their effects on interface pressures could be used to improve individual socket design.

Adult↗
PubMed2000

Comparison of the pharmacokinetic profiles of soluble aspirin and solid paracetamol tablets in fed and fasted volunteers.

The aim of this study was to investigate the absorption of popular preparations of two common analgesics--soluble aspirin and solid paracetamol tablets. An open, randomised, crossover study design was used to compare the pharmacokinetic parameters of soluble aspirin and solid paracetamol tablets in 16 healthy, male volunteers from the University of the Witwatersrand, South Africa, in both fed and fasted states. Plasma concentrations of paracetamol, aspirin and salicylic acid were measured. It was found that the rate of absorption was significantly faster for soluble aspirin than for solid paracetamol, regardless of fed or fasting state, considering time to maximum concentration (p < 0.01), time to first quantifiable concentrations (p < 0.05) and absorption rate (p < 0.01). Absorption rate was significantly affected by food for both soluble aspirin (p = 0.028) and for solid paracetamol (p = 0.0003). Time to maximum concentration was not significantly affected by food for soluble aspirin (p = 0.17) but significantly lengthened for solid paracetamol (p = 0.0003). The extent of absorption was affected by food in terms of maximum concentration for both drugs (p = 0.0001), with a reduction of 49% in the fed state for solid paracetamol compared to 18% for soluble aspirin, the difference between the drugs being statistically significant (p = 0.0024). The overall bioavailability of soluble aspirin was unaffected by food and the bioavailability of salicylic acid was increased in the fed state, whereas that of solid paracetamol was lowered in the fed state. Greater inter-individual variation was seen in paracetamol concentrations compared with aspirin or salicylic acid levels. In conclusion, these results show that the absorption of soluble aspirin is largely unaffected by food, whereas, in the same volunteers, the absorption of solid paracetamol tablets is greatly affected. In some volunteers, maximum plasma concentrations of paracetamol following food did not reach levels previously reported to be required for effective analgesia, and this may have implications for pain relief in some individuals. The practice in some individuals of taking aspirin tablets after food to minimise potential gastric disturbance should not affect the level of analgesia.

Acetaminophen↗
PubMed1993

Novel electrochemical device for the detection of cholesterol or glucose.

A thin-layer twin-electrode electrochemical cell in which the working and auxiliary electrodes are facing each other and which contains the appropriate enzyme and a mediator was used for the determination of cholesterol or glucose. A steady-state diffusion-controlled response was obtained for cholesterol whereas for glucose the response was limited by diffusion and kinetics. Simulation of the system showed that a steady-state response is obtained, in the absence of kinetic complications, after a time of 0.01 d2/Ds, where d is the distance between the two electrodes and D is the diffusion coefficient of the mediator. Linear plots of steady-state current versus concentration were obtained for cholesterol and glucose. The results were compared with those expected theoretically and a thin-layer capillary fill device is proposed.

Cholesterol↗
PubMed1987

Transbronchial biopsy during mechanical ventilation.

The diagnostic yield and risks of transbronchial biopsy (TBB) during mechanical ventilation were assessed in 13 patients with progressive pulmonary infiltrates. TBB was of considerable diagnostic value in ten patients and useful in excluding potentially treatable infections in the remaining three patients. Complications included two pneumothoraces, pulmonary hemorrhage in one case, and supraventricular tachycardia in another. No fatalities were attributable to TBB. TBB proved to be a relatively safe procedure, with a high diagnostic yield in these critically ill patients.

Acute Disease↗
PubMed1987

The value of Swan-Ganz catheterization and volume loading in preventing renal failure in patients undergoing abdominal aneurysmectomy.

A prospective analysis of 61 patients undergoing abdominal aneurysmectomy is presented. When compared with 87 historical controls we have shown that the incidence of hypotensive episodes (31 out of 62 patients in the original study compared with 13 out of 44 patients in the prospective analysis) is significantly reduced when fluid balance is monitored invasively using the pulmonary artery wedge pressure and keeping it at 10 mm H2O (p less than 0.03). Renal dysfunction, defined as a significant drop in urine output and a doubling of the serum creatinine, occurred in only 10% of patients compared with 33% in the controls (p less than 0.001). The decreased prevalence of renal failure accounts for the reduction in mortality noted (p less than 0.01). There were 27 deaths (31%) amongst the patients in the earlier study compared with 9 (15%) in the prospective analysis. The pathogenetic mechanisms responsible for the development of renal failure following surgical manipulation of the abdominal aorta are reviewed.

Abdomen↗
PubMed1983

Entry of US medical school graduates into family practice residencies: a national study.

No authoritative source has reported the percentage of each medical school's graduates who enter family practice residency programs. This study is the first of a series of reports from the American Academy of Family Physicians to report such data. Approximately 12.8 percent of the 15,667 graduates of United States medical schools between July 1980 and June 1981 were first-year residents in family practice in December 1981. The West North Central Region reported the highest percentage of medical school graduates who were first-year residents in family practice programs in December 1981; the New England and Middle Atlantic regions had the lowest percentages. Medical school graduates from publicly funded medical schools were twice as likely to be first-year residents in family practice in December 1981 as were graduates from privately funded medical schools.

Career Choice↗
PubMed1981

Hodgkin's disease in South African children.

Thirty South African children with Hodgkin's disease were studied over a 7-year period (1970 - 1977). Males outnumbered females by 5:1. The most frequent histological pattern encountered was mixed cellularity (72%). Fourteen patients with stage I, II or IIIA disease were treated with radiation therapy alone, and all achieved a complete remission with a median duration of remission in excess of 48 months. Sixteen patients with stage III or IV disease received combination chemotherapy (MOPP regimen), and 13 achieved a complete remission with a median duration of remission in excess of 48 months. The overall median survival was in excess of 60 months. Seven patients died during the study period, 4 of Hodgkin's disease and 3 of other causes. There was no significant difference in treatment response or survival between Black and White children.

Adolescent↗
PubMed1981

Practice locations of family practice residency graduates.

The purpose of this study was to examine the practice location patterns of 1970-1978 graduates of family practice residency programs. Comparisons were made between the number of graduates practicing in a region in 1979 with the number of all graduates during 1970-1978 from family practice residency programs in that region and with the number of all graduates from medical schools in that region who eventually completed family practice residencies elsewhere. The Middle Atlantic and West North Central regions showed marked decreases, while the Mountain, Pacific, and New England regions showed increases. The majority practiced more than 100 miles from their residency program. Most respondents practicing in a nonmetropolitan area moved outside of a 100-mile radius from their residencies. Most respondents practicing in a metropolitan area practiced within the 100-mile radius. Physicians were likely to be practicing in a community similar to their backgrounds.

Family Practice↗
PubMed1981

Hospital privileges for family physicians: a national study of office based members of the American Academy of Family physicians.

In 1980 the American Academy of Family Physicians sampled those active members who were nonfederal, office based physicians in direct patient care to ascertain the characteristics of their hospital practices. The sample was stratified by the nine US census regions: 83.7 percent of the 5,216 active members in the sample responded. The vast majority of family physician/general practitioners in direct patient care in an office based setting have hospital admission privileges in one or more hospitals. A higher percentage of family physicians/general practitioners in census regions west of the Mississippi River were likely to have privileges in obstetrics and surgery than those in eastern regions. Moreover, family physicians/general practitioners in the nonmetropolitan areas of each census region were more likely to have hospital privileges at any level than were their colleagues in the metropolitan areas of the same region. Although there were disparities in the proportions of family physician/general practitioners with certain hospital privileges among regions, the vast majority in each region indicated that the privileges afforded them were appropriate.

Data Collection↗
PubMed1981

Hospital privileges for graduates of family practice residency programs.

In 1979 the American Academy of Family Physicians, as the first phase of a long-range study of family practice residency outcomes, surveyed graduates for the years 1970 through 1978 who were diplomates of the American Board of Family Practice. This report is limited to an overview analysis of the hospital admission and practice privileges of the 3,021 respondents actively practicing family medicine in the United States. A higher percentage of respondents in census regions west of the Mississippi River were more likely to have privileges in obstetrics and surgery than were respondents in eastern regions. Respondents in nonmetropolitan areas were more likely to have hospital privileges than were respondents in metropolitan areas.

Family Practice↗
PubMedDate not supplied

Training needs of psychiatric intensive care staff.

AIM: A survey was carried out to identify the education and training needs of psychiatric intensive care staff and the preferred type of training course. Demand for a specific psychiatric intensive care unit (PICU)/lowsecure training course was also examined. METHOD: A convenience sample was taken from delegates attending a National Association of Psychiatric Intensive Care Units (NAPICUs) conference. Questionnaires were given to 130 delegates and a mail-shot was sent to ward managers on 13 PICUs in London. RESULTS: The findings were that staff wanted further training in four main areas: the management of violence and aggression; psychological therapies; communication and engagement skills; and rapid tranquillisation. Most respondents indicated that they would like a course developed specifically for PICU staff at degree level in modular format. CONCLUSION: This small-scale study highlights the need for further provision of training for PICU staff and provides an insight into their education and training needs. The findings could have significant implications for developing new approaches to education and training for practitioners working with severely ill psychiatric patients.

Attitude of Health Personnel↗
PubMedDate not supplied

Entry of U.S. medical school graduates into family practice residencies: 1983-84.

This study is the third of a series from the American Academy of Family Physicians to report on the percentage of each medical school's graduates who enter family practice residency programs. Approximately 12.5% of the 15,739 graduates of United States medical schools between July 1982 and June 1983 were residents in family practice in December 1983. The Mountain and Pacific regions report the highest percentage of medical school graduates who were residents in family practice programs in December 1983; the New England and Middle Atlantic regions had the lowest percentages. Medical school graduates from publicly funded medical schools were twice as likely to be residents in family practice in December 1983 as were graduates from privately funded schools. The independent variable indicated by the presence of a family practice department in the medical school is the only variable which entered into a step-wise linear regression on a transformation of the dependent variable, percentage of graduates entering an FP residency program.

Family Practice↗
PubMedDate not supplied

Entry of U.S. medical school graduates into family practice residencies: a national study, December 1983.

This study is the second in a series of reports from the American Academy of Family Physicians on the percentage of each medical school's graduates who enter family practice residency programs. Approximately 12.9% of the 15,985 graduates of United States medical schools between July 1981 and June 1982 were first-year residents in family practice in December 1982. The West North Central region reports the highest percentage of medical school graduates who were first-year residents in family practice programs in December 1982; the New England and Middle Atlantic regions had the lowest percentage. Medical school graduates from publicly funded medical schools were twice as likely to be first-year residents in family practice in December 1982 as were graduates from privately funded medical schools.

Family Practice↗