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Biomedical subjects

K L Reynolds

Publications and source records attributed to K L Reynolds.

At least 19 recordsLinked to original sources
PubMed1995

Friction blisters. Pathophysiology, prevention and treatment.

Blisters occur frequently, especially in vigorously active populations. Studies using respective rubbing techniques show that blisters result from frictional forces that mechanically separate epidermal cells at level of the stratum spinosum. Hydrostatic pressure causes the area of the separation to fill with a fluid that is similar in composition to plasma but has a lower protein level. About 6 hours after formation of the blister, cells in the blister base begin to take amino acids and nucleosides; at 24 hours, there is high mitotic activity in the basal cells; at 48 and 120 hours, new stratum granulosum and stratum corneum, respectively, can be seen. The magnitude of frictional forces (Ff) and the number of times that an object cycles across the skin determine the probability of blister development - the higher the Ff, the fewer the cycles necessary to produce a blister. Moist skin increases Ff, but very dry or very wet skin necessary to produce a blister. Moist skin increases Ff, but very dry or very wet skin decreases Ff. Blisters are more likely in skin areas that have a thick horny layer held tightly to underlying structures (e.g. palms of the hands or soles of the feet). More vigorous activity and the carrying of heavy loads during locomotion both appear to increase the likelihood of foot blisters. Antiperspirants with emollients and drying powders applied to the foot do not appear to decrease the probability of friction blisters. There is some evidence that foot blister incidence can be reduced by closed cell neoprene insoles. Wearing foot socks composed of acrylic results in fewer foot blisters in runners. A thin polyester sock, combined with a thick wool or polypropylene sock that maintains its bulk when exposed to sweat and compression reduces blister incidence in Marine recruits. Recent exposure of the skin to repeated low intensity Ff results in a number of adaptations including cellular proliferation and epidermal thickening, which may reduce the likelihood of blisters. More well-designed studies are necessary to determine which prevention strategies actually decrease blister probability. Clinical experience suggests draining intact blisters and maintaining the blister roof results in the least patient discomfort and may reduce the possibility of secondary infection. Treating deroofed blisters with hydrocolloid dressings provides pain relief and may allow patients to continue physical activity if necessary. There is no evidence that antibiotics influence blister healing. Clinical trials are needed to determine the efficacy of various blister treatment methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Blister↗
PubMed1991

Physiological responses to prolonged treadmill walking with external loads.

Limited information is available regarding the physiological responses to prolonged load carriage. This study determined the energy cost of prolonged treadmill walking (fixed distance of 12 km) at speeds of 1.10 m.s-1, 1.35 m.s-1, and 1.60 m.s-1, unloaded (clothing mass 5.2 kg) and with external loads of 31.5 and 49.4 kg. Fifteen male subjects performed nine trials in random order over a 6-week period. Oxygen uptake (VO2) was determined at the end of the first 10 min and every 20 min thereafter. A 10-min rest period was allowed following each 50 min of walking. No changes occurred in VO2 over time in the unloaded condition at any speed. The 31.5 and 49.4 kg loads, however, produced significant increases (ranging from 10 to 18%) at the two fastest and at all three speeds, respectively, even at initial exercise intensities less than 30% VO2max. In addition, the 49.4 kg load elicited a significantly higher (P less than 0.05) VO2 than did the 31.5 kg load at all speeds. The measured values of metabolic cost were also compared to those predicted using the formula of Pandolf et al. In trials where VO2 increased significantly over time, predicted values underestimated the actual metabolic cost during the final minute by 10-16%. It is concluded that energy cost during prolonged load carriage is not constant but increases significantly over time even at low relative exercise intensities. It is further concluded that applying the prediction model which estimates energy expenditure from short-term load carriage efforts to prolonged load carriage can result in significant underestimations of the actual energy cost.

Adult↗
PubMed1990

The effects of graded exercise on plasma proenkephalin peptide F and catecholamine responses at sea level.

The purpose of this study was to evaluate the effects of graded treadmill exercise on plasma preproenkephalin peptide F immunoreactivity and concomitant catecholamine responses at sea level (elevation, 50 m). Few data exist regarding the sea-level responses of plasma peptide F immunoreactivity to exercise. thirty-five healthy men performed a graded exercise test on a motor-driven treadmill at the relative exercise intensities of 25, 50, 75, and 100% of maximum oxygen consumption (VO2max). Significant (P less than 0.05) increases above rest were observed for plasma peptide F immunoreactivity and norepinephrine at 75 and 100% of the VO2 max and at 5 min into recovery. Significant increases in plasma epinephrine were observed at 75 and 100% of VO2max. Whole blood lactate significantly increased above resting values at 50, 75, and 100% of the VO2max and at 5 min into recovery. These data demonstrate that exercise stress increases plasma peptide F immunoreactivity levels at sea level. While the exercise response patterns of peptide F immunoreactivity are similar to catecholamines and blood lactate responses, no bivariate relationships were observed. These data show that sea-level response patterns to graded exercise are similar to those previously observed at moderate altitude (elevation, 2200 m).

Adult↗
PubMed1989

Influence of demographic factors on cyclosporine pharmacokinetics in adult uremic patients.

The causes of variability in cyclosporine (CS) clearance (CL) are mostly unknown. The pharmacokinetics of CS were studied in 30 adult uremic patients after single intravenous and oral doses by analyzing serial concentrations in serum by radioimmunoassay (SR) and in whole blood by radioimmunoassay (WR) and high pressure liquid chromatography (WH). Bioavailability (F) and CL were calculated by noncompartmental models and were significantly different depending upon the assay method except for FSR = FWR: FSR = 43.2 +/- 21.7%; FWR = 43.5 +/- 18.5%; FWH = 36.4 +/- 17.3%; CLSR = 849 +/- 363 ml/min; CLWR = 380 +/- 156 ml/min; CLWH = 559 +/- 174 ml/min. The age of the patients and parameters describing body size such as weight, surface area and percent of ideal weight were not correlated with CL. The height of the patients correlated with CLWH but not CLSR or CLWR. Parameters responsible for CS binding in blood such as cholesterol, triglyceride, hemoglobin concentration or hematocrit did not explain variability in CL. Of the factors indicative of liver function alanine transaminase activity but not aspartate transaminase, lactate dehydrogenase, alkaline phosphatase activity nor total bilirubin concentration in serum was correlated with CL. F was not correlated with any of the demographic factors except for alanine transaminase. None of the significant correlations explained enough of the variability to afford a reliable prediction of CL or F.

Adolescent↗
PubMed1987

An integrated system for interstitial 192Ir implants.

An efficient system for preparing, afterloading, and removing interstitial 192Ir strands has been developed. Use of the system reduces the risk of personnel exposure and eliminates some patient discomfort. The system is "integrated" in that all aspects of the implantation process are considered, from source preparation to source removal. Strand preparation is facilitated by an "assembly line" process using shielded equipment. Components include a handling block for measuring and cutting active strands, a mirror, and a transport container. Afterloading and removal techniques use quick release devices and several forms of afterloading tubing and catheters, each terminated by a Luer lock adapter. Both blind-end and through-and-through implants are possible. Each 192Ir strand, threaded through an injection cap that mates with the Luer lock adapter, is quickly inserted into its tubing or catheter and locked into place. No crimping is required and no additional positioning of the sources is needed. Strand removal is easily accomplished by unlocking and removing the injection cap. The strands receive no mechanical damage and can be reused after appropriate cleaning. More than 100 cases have been performed without incident. Applications include head/neck, breast, and template and non-template vaginal wall treatments.

Brachytherapy↗
PubMed1986

Promptness of antibiotic therapy in acute bacterial meningitis.

We reviewed 135 cases of acute community-acquired bacterial meningitis at a municipal teaching hospital during a six-year period, with special emphasis on promptness of initial antimicrobial therapy. Overall mortality was 5% for the 121 childhood cases, compared to 43% for the 14 adult cases (P less than .001). The mean duration between arrival in the emergency department and the administration of appropriate antibiotics was 2.1 hours for the pediatric cases, compared to 4.9 hours for the adult cases (P less than .02). Factors that may contribute to delays in institution of appropriate antimicrobial therapy for adult patients with meningitis include the relative infrequency of this condition, the presence of concomitant disease processes, and the frequent practice of obtaining a computed tomography scan prior to performing lumbar puncture. Prompt institution of antimicrobial therapy for acute meningitis, especially for adult pneumococcal meningitis, remains a major challenge for emergency physicians.

Acute Disease↗
PubMed1986

Endemic bacteremia in Columbia, South Carolina.

Between 1977 and 1981, there were 4.9 episodes of community-acquired bacteremia and 5.1 episodes of hospital-acquired bacteremia per 1,000 patients in the four major hospitals of one metropolitan area. Case fatality rates were 30.1 per cent based on deaths due to all causes and 14.7 per cent based on deaths attributed specifically to bacteremia. Patients who experienced bacteremia had a 12-fold excess in mortality compared with other patients. Bacteremia occurred more frequently and was associated with greater case fatality rates at university-affiliated teaching hospitals compared with nonteaching community hospitals. At the nonteaching community hospitals, the odds of mortality for patients with bacteremia were lower even after adjustment for age, sex, severity of underlying medical problems, and severity of infection. Patients on private services at a teaching municipal hospital experienced greater odds of mortality compared with private patients at two nonteaching community hospitals. These latter observations may reflect, at least in part, limitations in the standard parameters used for determining severity of underlying medical problems and severity of infection.

Adolescent↗
PubMed1985

Mortality associated with enterococcal bacteremia.

Our data support the concept that enterococcal bacteremia provides a marker for life-threatening disease processes but, apart from endocarditis, seldom explains the immediate cause of death. Although over-all mortality among 189 patients who experienced 190 episodes of enterococcal bacteremia was 39 per cent, only 14 deaths were attributed directly to the episode of bacteremia on the basis of definitions used in this study. Upon closer scrutiny, the role of enterococcal infection even in these 14 deaths was not entirely clear except for one fatal instance of endocarditis. We could not correlate outcome with use of specific antimicrobial therapy directed against enterococci.

Adolescent↗
PubMed1984

Bacteroides bacteremia. Analysis of 142 episodes from one metropolitan area.

Overall mortality for 142 patients with Bacteroides bacteremia encountered in the four hospitals of one metropolitan area between 1977 and 1982 was 41%. Only 43% of deaths of these patients, however, were attributed directly to Bacteroides infection according to the criteria used in this study. Deaths of patients with Bacteroides bacteremia, compared with deaths of patients with bacteremia due to aerobic gram-negative rods, were less likely to occur early after onset of bacteremia. Choice of antimicrobial therapy had no obvious relationship to eventual outcome. Nonobstetrical Bacteroides bacteremia identifies a group of patients at high risk of death during hospitalization. The diversity of both clinical and microbiologic features of these infections, however, makes specific recommendations regarding optimum therapy difficult to formulate.

Adolescent↗
PubMed1984

Community-acquired bacteremic urinary tract infection: epidemiology and outcome.

We studied 313 episodes of community-acquired bacteremic urinary tract infection in 4 hospitals of 1 metropolitan area from 1977 to 1981. Although over-all mortality rate for these patients was 13.7 percent, only 15 deaths were attributed directly to bacteremic urinary tract infection according to the criteria used in this study. Of these 15 deaths 13 occurred among patients on medical services, all but 1 of whom had alcoholic liver disease, malignancy and/or chronic neurologic disease. The other patient had brittle diabetes mellitus with renal papillary necrosis and chronic renal failure. In this population 10.4 episodes of community-acquired bacteremic urinary tract infection occurred per 10,000 patients. However, these infections appeared to explain the deaths only of patients with severe underlying diseases.

Adolescent↗
PubMed1984

Hospital-acquired bacteremic urinary tract infection: epidemiology and outcome.

Analysis of 221 episodes of hospital-acquired bacteremic urinary tract infection in 4 hospitals of 1 metropolitan area from 1977 to 1981 revealed an over-all mortality rate of 30.8 per cent. The mortality rate attributed specifically to bacteremic urinary tract infection was 12.7 per cent. Of the 28 patients whose deaths were attributed directly to hospital-acquired bacteremic urinary tract infection 19 were on medical services and all had focal or diffuse central nervous system disease, malignancy, alcoholic liver disease or cirrhosis, advanced arteriosclerosis with renal failure and/or diabetes mellitus with obliterative peripheral vascular disease. Extrapolation of these data suggests that 3,520 deaths in the United States each year are directly caused by hospital-acquired bacteremic urinary tract infection but that these deaths may be limited virtually to high risk patients with poor prognoses from underlying diseases.

Adolescent↗
PubMed1984

Bacteremic nosocomial pneumonia. Analysis of 172 episodes from a single metropolitan area.

We studied 172 episodes of bacteremia attributed to nosocomial pneumonia in 168 patients, observed in the 4 major hospitals of a single metropolitan area over a 5-yr period. Overall mortality for these patients was 58%. Deaths attributed directly to nosocomial pneumonia occurred almost exclusively in patients with serious and largely irreversible underlying diseases. These data confirm the high mortality associated with endemic hospital-acquired pneumonia. Although some deaths appear to be preventable, primarily by measures designed to reduce the risk of aspiration, analysis of the data herein raises doubts whether overall mortality can be significantly reduced by currently available measures.

Adolescent↗
PubMed1984

Bacteremia in obstetrics and gynecology.

Surveillance of all episodes of bacteremia in the four major hospitals of a metropolitan area of 400,000 population between 1977 and 1981 revealed that bacteremia was documented in only 92 patients on obstetrics and gynecology services. Death was attributed to bacteremia in only four of these patients, three of whom had severe underlying diseases. These data confirm that death due to bacteremia in present-day obstetric and gynecology practice is extremely uncommon.

Adult↗
PubMed1983

Bacteremia associated with decubitus ulcers.

We studied 104 episodes of bacteremia in 102 patients with decubitus ulcers observed over five years in the hospitals of one metropolitan area. The ulcers were considered to be the "probable" source of bacteremia in 49% of episodes. Another site of infection was documented in 86% of patients. Proteus mirabilis, Staphylococcus aureus, and Escherichia coli were the most frequent blood isolates in these patients, but only Bacteroides species correlated with "probable" origin of bacteremia from the ulcers. The overall mortality was 55%, with 51% of deaths being attributed to infection. These findings emphasize the importance of decubitus ulcers as potential sources of bacteremia in hospitalized patients.

Adolescent↗
PubMedDate not supplied

Analysis of 1,186 episodes of gram-negative bacteremia in non-university hospitals: the effects of antimicrobial therapy.

Over the five-year period 1977-1981, we studied 1,186 episodes of bacteremia due to Enterobacteriaceae and Pseudomonadaceae in the four non-university hospitals of a single metropolitan area. Overall patient mortality was 36.3%, and mortality attributed specifically to infection was 19.0%. The importance of severity of underlying disease, site of infection, microorganism, and age--previously determined to be prognostic factors in studies conducted at tertiary-care centers--was confirmed. Appropriate initial antimicrobial therapy (defined as the administration of an effective agent in adequate dose and by a suitable route of administration on the first calendar day on which blood cultures were positive) did not improve survival compared with the use of an ineffective antimicrobial agent or no therapy at all. However, appropriate antimicrobial therapy subsequent to the first calendar day on which blood cultures were positive clearly affected survival. These findings confirm previous conclusions regarding the frequency and severity of gram-negative bacteremia and the overall impact of antimicrobial therapy on this condition. These studies also suggest the possibility that the definition of optimal initial therapy in some groups of patients should be reconsidered.

Adolescent↗