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Biomedical subjects

R M Allman

Publications and source records attributed to R M Allman.

At least 37 records · Page 2Linked to original sources
PubMed1994

A phase II study to evaluate recombinant platelet-derived growth factor-BB in the treatment of stage 3 and 4 pressure ulcers.

OBJECTIVE: To determine the efficacy of the daily topical application of recombinant platelet-derived growth factor-BB (rPDGF-BB), a recognized vulnerary agent, in the treatment of deep pressure ulcers. DESIGN: Prospective, randomized, double-blind trial. SETTING: Patients were treated in a nursing home or a hospital setting before transfer to a nursing home. PATIENTS: Eligibility criteria included a clean pressure ulcer that had been adequately debrided and the absence of severe cardiac, pulmonary, or renal conditions. The causes of the ulcers were not related to a venous or arterial vascular disorder. The patients were elderly (mean age, 68 to 74 years). INTERVENTIONS: After randomization, patients were given daily topical aqueous rPDGF-BB (dosage, 100 or 300 micrograms/mL) or placebo and saline gauze dressings were applied daily in addition to frequent turning. MAIN OUTCOME MEASURE: Serial volume measurements of the healing wounds were taken using alginate molds. RESULTS: The ulcers of 41 patients were analyzed. At the end of 28 days, median ulcer volumes had decreased to 83%, 29%, and 40% of the initial size in the groups receiving placebo, rPDGF-BB, 100 micrograms/dL, and rPDGF-BB, 300 micrograms/mL, respectively. When adjusted for initial volume, ulcer volume after 28 days of treatment was smaller in the rPDGF-BB-treated groups compared with the placebo group (analysis of covariance, P = .056). Ulcers in the two rPDGF-BB-treated groups were significantly smaller in volume compared with those in the placebo group, using a linear contrast procedure. CONCLUSIONS: Data from this small trial suggest that local application of rPDGF-BB may be of therapeutic benefit in accelerating the healing of chronic pressure ulcers.

Administration, Topical↗
PubMed1994

Tissue repair processes in healing chronic pressure ulcers treated with recombinant platelet-derived growth factor BB.

Cellular and molecular mechanisms responsible for the observed vulnerary effects of recombinant human platelet-derived growth factor BB (rP-DGF-BB) in man have not been elucidated. In a double-blinded trial, patients having chronic pressure ulcers were treated topically with either rPDGF-BB or placebo for 28 days. To explore how rPDGF-BB may induce chronic wounds to heal, biopsies were taken from the ulcers of a cohort of 20 patients from the trial and evaluated in a blinded fashion by light microscopy for 1), fibroblast content, 2) neovessel formation, and 3), collagen deposition. Electron microscopy also was used to assess fibroblast activation and collagen deposition. Before initiation of therapy most wounds had few fibroblasts and most of those present were not activated. When mean scores for the total active treatment phase (days 8, 15, and 29) for rPDGF-BB-treated ulcers were compared with the scores for placebo-treated ulcers, fibroblast content was significantly higher for the rPDGF-BB-treated ulcers (P = 0.03, Kruskal-Wallis test). More significant differences in fibroblast and neovessel content were observed when six nonhealing wounds were eliminated from the analysis (three placebo, three treatment). Thus, in all healing wounds, rPDGF-BB therapy significantly increased fibroblast (P = 0.0007) and neovessel (P = 0.02) content. These results were correlated with increased collagen fibrillogenesis by fibroblasts from healing rPDGF-BB-treated wounds, as assessed by intracellular procollagen type I immunostaining, and by electron microscopy, and were concordant with clinical measurements (eg, area of ulcer opening and ulcer volume) which showed greater healing in rPDGF-BB-treated wounds. These results suggest induction of fibroblast proliferation and differentiation is one mechanism by which rPDGF-BB can accelerate wound healing and that rPDGF-BB can augment healing responses within a majority of, but not all, nonhealing chronic pressure ulcers in man.

Antibodies↗
PubMed1993

Age-related variability in the use of cardiovascular imaging procedures.

OBJECTIVE: To determine if older patients undergo fewer cardiovascular imaging procedures (CIPs) than younger patients when admitted to a tertiary care academic medical center for an acute myocardial infarction (MI), after adjusting for disease severity and comorbidities. DESIGN: Non-current prospective cohort study. SETTING: Urban tertiary care academic medical center. PATIENTS: Medical records of 294 patients admitted and diagnosed with an acute MI between January 1990 and April 1991 were reviewed. MEASUREMENTS: The total number of different CIPs performed during hospitalization was determined. Cardiac catheterizations, echocardiograms, radionuclide ventriculograms, and thallium scans counted as CIPs. Disease severity was assessed by the Acute Physiology Score (APS) of APACHE II, admission Killip's Classification, and peak creatine phosphokinase (CPK) levels. Comorbidities were assessed using a modified Comorbidity Damage Index of Charlson. RESULTS: The mean (+/- SD) number of different CIPs performed during hospitalization was significantly less for those > or = 75 years old (1.3 +/- 1.0) than for those < 75 years old (1.7 +/- 1.0) (P = 0.01), and CIP number negatively correlated with age (Spearman r = -0.178; P = 0.01). Mean CIP number decreased from 2.0 +/- 1.1 for those < 45 years old to 0.9 +/- 0.6 for those > or = 85 years old (P = 0.02). Other factors positively associated (P < 0.10) with CIP number were: CPK values in the highest quartile of the study population (> 355 U/L); admission to a cardiology, medical, or family practice service; no CIP performed at an outside hospital prior to transfer; admission Killip's Classification of less than IV, and a Q-wave MI. After adjusting for these variables in a multiple regression model, age > or = 75 remained an independent predictor of decreased CIP use (P = 0.003). The modified comorbidity index score and the APS score, a general measure of severity of illness, were not significantly associated with CIP use. When procedures were examined individually, no significant age-related differences were noted in the use of thallium scans, radionuclide ventriculograms, or echocardiograms. Older patients did, however, remain less likely to undergo cardiac catheterizations (P < 0.001). CONCLUSION: Older patients, regardless of underlying disease severity or comorbidities, undergo fewer invasive cardiovascular evaluations than younger patients when admitted to a tertiary care academic medical center for an acute MI.

Age Distribution↗
PubMed1992

Sex- and race-related differences in liver-associated serum chemistry tests in young adults in the CARDIA study.

Simultaneous multiple automated analyses of liver function can be performed quickly and cheaply, but their usefulness in mass screening is questionable. Reference intervals are frequently applied without regard to race and sex, despite the fact that reported values may vary considerably in relation to these factors. Serum analyte results for greater than 5000 black and white men and women in the CARDIA Study showed clinically and statistically significant differences by race and sex for values of aspartate aminotransferase, gamma-glutamyltransferase, alkaline phosphatase, total bilirubin, total protein, and albumin; these differences were not explained by differences in age, body mass, reported ethanol intake, smoking, or oral contraceptive use. Results for at least one of these six tests were out of range in 38% of the men and 19% of the women. Sex- and race-specific reference intervals are recommended to decrease the frequency of values reported as abnormal in otherwise healthy young adults.

Adult↗
PubMed1989

Precise measurement of vertebral bone density using computed tomography without the use of an external reference phantom.

Bone density measurement by quantitative computed tomography (QCT) commonly uses an external reference phantom to decrease scan-to-scan and scanner-to-scanner variability. However, the peripheral location of these phantoms and other phantom variables is also responsible for a measurable degradation in accuracy and precision. Due to non-uniform artifacts such as beam hardening, scatter, and volume averaging, the ideal reference phantom should be as close to the target tissue as possible. This investigation developed and tested a computer program that uses paraspinal muscle and fat tissue as internal reference standards in an effort to eliminate the need for an external phantom. Because of their proximity, these internal reference tissues can be assumed to reflect more accurately the local changes in the x-ray spectra and scatter distribution at the target tissue. A user interactive computerized histogram plotting technique enabled the derivation of reproducible CT numbers for muscle, fat, and trabecular bone. Preliminary results indicate that the use of internal reference tissues with the histogram technique may improve reproducibility of scan-to-scan measurements as well as inter-scanner precision. Reproducibility studies on 165 images with intentional region-of-interest (ROI) mispositioning of 1.5, 2.5, or 3.5 mm yielded a precision of better than 1% for normals and 1% to 2% for osteoporotic patients--a twofold improvement over the precision from similar tests using the standard technique with an external reference phantom. Such improvements in precision are essential for QCT to be clinically useful as a noninvasive modality for measurement of the very small annual changes in bone mineral density.

Bone Density↗
PubMed1989

The prevention and management of pressure ulcers.

Pressure ulcers are a common problem for older persons. Complications associated with pressure ulcers include infection and even death for some patients. Pressure is the primary pathogenic factor, but shearing forces, friction, and moisture are also important. Immobility, nutritional status, and age-related factors seem to be significant risk factors. Preventive care includes use of assessment tools to identify high risk patients, frequent repositioning, air or foam mattresses that reduce pressure over bony prominences, as well as careful attention to optimizing the overall patient condition. When pressure ulcers do develop, the treatment plan should include adequate nutrition including protein, vitamin C, and zinc supplements as indicated; systemic antibiotics for sepsis, cellulitis, osteomyelitis, or the prevention of bacterial endocarditis; and local wound care that eliminates necrotic tissue, decreases bacterial load, and provides a physiologic, pressure-free environment allowing the wound to heal. Specialized beds may be considered in some patients, particularly those with larger ulcers. Surgery is an option in older persons who are operative candidates. For some patients with pressure ulcers, appropriate treatment goals may focus on providing comfort rather than curing the ulcer.

Aged↗
PubMed1989

Epidemiology of pressure sores in different populations.

The data available regarding the epidemiology of pressure ulcers suggest that they are a serious public health problem in the United States, particularly among the elderly. Factors that are associated with increased risk of pressure ulcer development are being defined in different populations. Future studies need to include clear-cut definitions of pressure ulcers that permit lesions of varying severity to be distinguished. Such research should ultimately facilitate the development of more effective prevention strategies for patients at highest risk.

Aged↗
PubMed1989

Basic evaluation of older persons with hypertension.

To achieve the objectives of the baseline evaluation of older persons with hypertension, age-related changes that affect blood pressure measurement, assessment of target-organ effects, cardiovascular disease risk, and comorbidities need to be recognized. Careful attention to recommended procedures for blood pressure measurement, conducting a history, performing a physical examination, and using laboratory tests will allow the physician to confirm the presence of hypertension; to assess its effects on target organs; to determine cardiovascular risk status relating to other factors; and to identify other diseases, laboratory abnormalities, or psychosocial factors that may affect subsequent management.

Age Factors↗
PubMed1988

Ranking: a year three follow-up in a different institution.

Ranking residents as a means of semiobjective evaluation of their overall performance was described in 1985. The predictive nature of pooled faculty ranking of residents was stressed. Ranking of resident total scores on The American College In-training Examination and American Board of Radiology written examination was noted to be statistically related to the pooled faculty ranking. Similarly, the faculty ranking was predictive of itself in subsequent rankings. A cohesiveness of faculty consensus was present such that small numbers (five minimum) were predictive of larger groups of participating faculty. All reported observations persist in the new institution. Exceptions to expected residency level of training stratification (eg, third-year residents ranking in the midst of first-year residents, second-year residents ranking above many third-year residents) continue to be the most useful observation in counseling residents. Additional information reported includes sensitivity of the ranking to improvement or nonimprovement of probated residents.

Achievement↗
PubMed1988

Neuropathic bone and joint disease.

The pathogenesis of the neuropathic joint has been a subject of controversy for many years. Two main theories of pathophysiologic pathways have evolved: (1) the neurotraumatic, which states that the changes result from mechanical trauma and repetitive injuries to an insensitive extremity or joint and (2) the neurovascular, which states that the changes result from a neurally initiated vascular reflex that leads to hyperemia, angiogenesis, and very active bone resorption by osteoclasts. Through clinical, radiographic, and pathologic observation, it appears evident that both pathways contribute to neuropathic bone and joint disease. Initially, the alteration of sympathetic control triggers a persistent hyperemia, leading to active bone resorption. There may or may not be associated pathologic fractures and subsequent repair. This depends upon the degree of joint insensitivity and whether or not it is subjected to continued weightbearing. If so, the neurotraumatic mechanisms come into play, but only secondarily.

Arthropathy, Neurogenic↗
PubMed1987

Air-fluidized beds or conventional therapy for pressure sores. A randomized trial.

STUDY OBJECTIVE: To compare the effectiveness and adverse effects of air-fluidized beds and conventional therapy for patients with pressure sores. DESIGN: Randomized trial with both masked and unmasked comparisons of outcome after a median follow-up of 13 days (range, 4 to 77 days). SETTING: Urban, academic referral, and primary care medical center. PATIENTS: Of 140 potentially eligible hospitalized patients with pressure sores, 72 consented to randomization; 65 (90%) completed the study. INTERVENTIONS: Thirty-one patients on air-fluidized beds (Clinitron Therapy, Support Systems International, Inc., Charleston, South Carolina) repositioned every 4 hours from 0700h to 2300h without use of other antipressure devices. Thirty-four patients on conventional therapy used an alternating air-mattress covered by a foam pad (Lapidus Air Float System, American Pharmaceal Company, Cincinnati, Ohio) on a regular hospital bed; were repositioned every 2 hours; and had elbow or heel pads as needed. Topical therapy was standardized for both groups. MEASUREMENTS AND MAIN RESULTS: Pressure sores showed a median decrease in total surface area (-1.2 cm2) on air-fluidized beds, but showed a median increase (+ 0.5 cm2) on conventional therapy; 95% confidence interval (CI) for the difference between medians, -9.2 to -0.6 cm2 (p = 0.01). Improvement, as assessed from serial color photographs by investigators masked to treatment group, occurred in 71% and 47%, respectively; 95% CI for the difference, 1% to 47% (p = 0.05). For pressure sores 7.8 cm2 or greater, outcome differences between air-fluidized beds and conventional therapy were greater: median total surface area change was -5.3 and +4.0 cm2, respectively; 95% CI for the difference, -42.2 to -3.2 cm2 (p = 0.01). Improvement rates were 62% and 29% respectively; 95% CI for difference, 1% to 65% (p = 0.05). After adjusting for other factors associated with sore outcome, the estimated relative odds of showing improvement with air-fluidized beds were 5.6-fold (95% CI, 1.4 to 21.7) greater than with conventional therapy (p = 0.01). No significant increase in adverse effects was seen with air-fluidized beds. CONCLUSIONS: Our findings suggest that air-fluidized beds are more effective than conventional therapy, particularly for large pressure sores. Studies are needed to determine the effectiveness of air-fluidized beds in long-term care settings.

Adult↗
PubMed1986

Pressure sores among hospitalized patients.

A cross-sectional survey was done to determine the prevalence of pressure sores in hospitalized patients and the factors associated with having a pressure sore in the hospital. Among 634 adult patients, 30 (4.7%; 3.1% to 6.3%, 95% confidence interval) had a pressure sore and 78 (12.3%; 9.8% to 14.8%) were at risk for a pressure sore because they had been confined to a bed or chair for at least 1 week. Comparing these two groups of patients, we found that fecal incontinence, diarrhea, fractures, urinary catheter use, decreased weight, dementia, and hypoalbuminemia were associated with having pressure sores (p less than or equal to 0.05). Using logistic regression analysis, hypoalbuminemia, fecal incontinence, and fractures remained significantly and independently associated with having a pressure sore (odds ratios = 3.0, 3.1, and 5.2, respectively; p less than or equal to 0.05). Our findings suggest that 17% (14% to 20%) of hospitalized patients have pressure sores or are at risk for them, and that hypoalbuminemia, fecal incontinence, and fractures may identify bedridden patients at greatest risk.

Adult↗
PubMed1985

Physician tolerance for uncertainty. Use of liver-spleen scans to detect metastases.

To gain insight into diagnostic test use, we interviewed 42 physicians who ordered 62 liver-spleen scans to detect possible metastases. Before receiving the actual scan results, physicians gave (1) pretest probability estimates for liver metastasis; (2) probability estimates and management plans given the most common scan results; and (3) probabilities above and below which they would stop the diagnostic workup (their decision thresholds). After learning the actual scan results, physicians gave their posttest probabilities and management plans. Thirteen physicians (31%) desired absolute certainty to rule in metastasis. Fifty percent planned further evaluations even when probability estimates of metastasis reached one of their probability targets for ending the workup. Greater attention to decision thresholds may improve physicians' understanding of their tolerance for diagnostic uncertainty and the ability of diagnostic tests to reduce it.

Attitude of Health Personnel↗
PubMed1985

Calcification and ossification in the arytenoid cartilage: incidence and patterns.

Calcification or ossification occurs early and commonly in the arytenoid cartilage. It may be difficult to detect, but there are only eight patterns that specifically identify ossification and calcification. Each arytenoid independently ossifies or calcifies. The cervical spine examination can specifically identify the patterns found at autopsy.

Adolescent↗
PubMed1983

Cadaver radiography in the teaching of gross anatomy.

The authors describe a new teaching method for first-year medical students, involving preparation and use of cadaver radiographs in the gross anatomy laboratory. A standard series of radiographs of each cadaver was obtained prior to dissection and provided to each group of students. This technique offers a unique opportunity for radiographic/anatomical/pathological correlation, facilitates an understanding of complex anatomical relationships, and illustrates the application of anatomical knowledge to clinical practice. It can also generate intense student enthusiasm and improve student-faculty communication and teaching relationships.

Anatomy↗