Pediatric interventional radiology workforce survey summary.
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Humans↗
Biomedical subjects
Paula K Roberson
Publications and source records attributed to Paula K Roberson.
Effects of muscle strength training and megestrol acetate on strength, muscle mass, and function in frail older people.
OBJECTIVES: To determine the independent and combined effects of progressive resistance muscle strength training (PRMST) and megestrol acetate (MA) on strength, muscle mass, and function in older recuperative care patients. DESIGN: Double-blind, randomized, controlled intervention using a two-by-two factorial design and conducted between 1999 and 2001. SETTING: University-affiliated Department of Veterans Affairs hospital. PARTICIPANTS: Twenty-nine patients (mean age 79.4 +/- 7.4, 90% white) aged 65 and older and had recent functional decline. INTERVENTIONS: After randomization to one of four treatment groups (low-resistance exercises plus 800 mg per day of MA or a placebo or high-intensity PRMST plus 800 mg/d of MA or placebo), subjects received training and the drug or placebo for 12 weeks. MEASUREMENTS: Change in muscle strength, mid-thigh muscle area, and aggregate functional performance score as assessed using analysis of covariance. RESULTS: Five subjects withdrew from the study before its completion. Based on intent-to-treat analyses, subjects who received high-intensity PRMST and placebo experienced the greatest strength gains. The addition of MA was associated with worse outcomes than with high-intensity exercise training alone, especially with regard to the leg exercises. Post hoc analysis demonstrated that subjects who received high-intensity PRMST and placebo experienced significantly greater percentage increases in leg strength than subjects in either of the MA treatment groups (P<.05 for each comparison). There was also a significant negative effect of MA on physical function. In general, subjects who received MA experienced a deterioration in aggregate physical function scores, whereas the remaining subjects improved (-0.80+/-0.40 vs 0.48+/-0.41, P=.04). There was not a significant interaction between exercise and MA for any outcome. CONCLUSION: High-intensity PRMST is a safe and well-tolerated exercise regimen for frail elderly patients. The addition of MA appears to blunt the beneficial effects of PRMST, resulting in less muscle strength and functional performance gains.
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Intralesional immunotherapy of warts with mumps, Candida, and Trichophyton skin test antigens: a single-blinded, randomized, and controlled trial.
BACKGROUND: Warts occur commonly in humans. Destructive modalities are generally the first physician-administered therapy. Other treatment options include immunotherapy. Intralesional immunotherapy using mumps, Candida, or Trichophyton skin test antigens has proved efficacy in the treatment of warts. OBJECTIVES: To determine rates of wart resolution in response to injection of antigen alone, antigen plus interferon alfa-2b, interferon alfa-2b alone, and normal saline; and to compare response according to viral type, major histocompatibility complex antigens, and peripheral blood mononuclear cell proliferation to autologous human papillomavirus antigen before and after injection. DESIGN: Randomized, single-blinded, placebo-controlled, clinical trial. SETTING: Medical school-based dermatology department. PATIENTS: Two hundred thirty-three patients clinically diagnosed as having 1 or more warts. Main Outcome Measure Clinical resolution of warts in response to intralesional immunotherapy. RESULTS: Responders were observed in all treatment arms, but were significantly more likely to have received antigen (P<.001). Resolution of distant untreated warts was observed, and was significantly more likely in subjects receiving antigen (P<.001). Interferon did not significantly enhance the response rate (P = .20) and did not differ from normal saline (P = .65). No viral type or major histocompatibility complex antigen correlated with response or lack of response (P>.99 and P = .86, respectively). A positive peripheral blood mononuclear cell proliferation assay result (2 times pretreatment levels) was significantly more likely among responders (P = .002). While there was no significant difference in response based on sex (P = .56), older subjects (>40 years) were less likely to respond (P = .01). CONCLUSIONS: Intralesional immunotherapy using injection of Candida, mumps, or Trichophyton skin test antigens is an effective treatment for warts, as indicated by significantly higher response rates and distant response rates in subjects receiving antigen. Viral type and major histocompatibility complex antigens did not seem to influence treatment response. Response is accompanied by proliferation of peripheral blood mononuclear cells to human papillomavirus antigens, suggesting that a human papillomavirus-directed cell-mediated immune response plays a role in wart resolution.
Adult↗
Hypoalbuminemia 3 months after hospital discharge: significance for long-term survival.
OBJECTIVES: To determine change in albumin from hospital discharge to 3-month follow-up and the prognostic significance of persistent hypoalbuminemia in older veteran patients. DESIGN: A prospective cohort study. SETTING: A geriatric rehabilitation unit of a university-affiliated Department of Veterans Affairs hospital. PARTICIPANTS: The study population consisted of 282 subjects (of 322 randomly selected discharges who were free of cancer and terminal conditions) that completed the 90-day postdischarge assessment; most were older (75.4+/-8.6), white (76%), and male (99%). MEASUREMENTS: Each subject completed a comprehensive discharge assessment, had a repeat albumin an average of 94 days later, and was then tracked for 5 years. The strongest predictors of survival were identified using Cox proportional hazards regression analysis. RESULTS: Between hospital discharge and the 3-month reassessment, albumins improved by more than 2 g/L in 122 subjects (43%), stayed the same in 112 subjects (40%), and deteriorated by more than 2 g/L in the rest. During follow-up, 190 subjects (67%) died. Of the 38 nutritional, functional, demographic, and illness severity variables evaluated, the 3-month postdischarge albumin was the strongest predictor of long-term mortality. Those with albumins less than 35 g/L had a 2.6 times greater mortality than those with albumins of 40 g/L or greater (relative risk=2.6, 95% confidence interval=1.8-3.8). After controlling for 3-month albumin, hospital-discharge albumin was not significantly associated with long-term mortality. CONCLUSION: In older people, a low serum albumin 3 months after hospital discharge is associated with a poor long-term prognosis. It is not known whether this represents ongoing inflammation or inadequate nutrition.
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Effects of muscle strength training and testosterone in frail elderly males.
PURPOSE: Determine the independent and combined effects of progressive resistance muscle strength training (PRMST) and testosterone on strength, muscle mass, and function in hypogonadal elderly male recuperative care patients. METHODS: Between 1999 and 2004, 71 subjects (mean age 78.2 +/- 6.4 yr, 86% white) were enrolled. After baseline one-repetition maximum (1RM) strength testing and then randomization to one of four treatment groups (low-resistance (20% of the 1RM) exercises and weekly injections of either 100 mg of testosterone enanthate or placebo or high-intensity PRMST (> or =80% 1RM) and weekly injections), each subject received training and injections for 12 wk. RESULTS: Ten subjects withdrew from the study before its completion. Based on intent-to-treat analyses, strength improved in all groups, but was greater with high-intensity PRMST compared with low-resistance exercise (e.g., leg press, (mean +/- SE), 28 +/- 4 vs 13 +/- 4%, P = 0.009). Although testosterone led to significantly greater increases in midthigh cross-sectional muscle area compared with placebo (7.9 +/- 1.3 vs 2.4 +/- 1.4%, P = 0.005), it produced only a nonsignificant trend toward greater strength gains (e.g., leg press 25 +/- 4 vs 16 +/- 4%, P = 0.144). Change in aggregate functional performance score (the sum of 4 functional performance test scores) did not differ between the four intervention groups nor with high-intensity PRMST compared with low-resistance exercise (7 +/- 5 vs 15 +/- 5%, P = 0.263). There was not a significant interaction between exercise and testosterone for any outcome. CONCLUSION: High-intensity PRMST is as safe and well tolerated as a similarly structured low-resistance exercise regimen for very frail elderly patients, but produces greater muscle strength improvements. The addition of testosterone leads to greater muscle size and a trend toward greater strength but did not produce a synergistic interaction with exercise. Neither intervention had a significant effect on functional performance.
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Intracranial clot lysis with intravenous microbubbles and transcranial ultrasound in swine.
BACKGROUND AND PURPOSE: Destruction of microbubbles by transcutaneous low-frequency ultrasound (LFUS) has been used to lyse adjacent clot and recanalize acutely thrombosed vessels. LFUS with intraarterial microbubbles has been shown to lyse cerebral clot rapidly in pigs without thrombolytic drugs. We hypothesized that intravenous platelet-targeted microbubbles with LFUS may be a rapid noninvasive technique to recanalize thrombosed intracerebral vessels. METHODS: After angiography, 0.5 cc of autogenous thrombus was injected into 1 ascending pharyngeal artery of a pig, occluding it and the rete mirabile. These vessels connect the carotid to the internal carotid and are the main cerebral blood supply. Saline control or intravenous decafluorobutane-sonicated dextrose albumin microbubbles tagged with a subtherapeutic quantity of glycoprotein 2b/3a receptor inhibitor eptifibatide (75 U/kg plus 12 cc of microbubbles administered over 21 minutes), or eptifibatide control, was given with transcutaneous temporal LFUS (1 MHz at 2.0 W/cm2) for 24 minutes. Angiography followed with scoring of declotting and flow. The same protocol was repeated on the contralateral side with the other test fluid so each animal received a saline control and either tagged microbubble or eptifibatide alone. RESULTS: Fifteen pigs completed the protocol with a mean clot age of 4.6 hours. Using tagged microbubbles, 6 of 8 achieved success compared with 0 of 7 receiving eptifibatide alone (P=0.007) and 1 of 15 receiving saline alone (P=0.02). CONCLUSIONS: Intravenous platelet-targeted microbubbles combined with transcranial LFUS can rapidly open acute intracranial thrombotic occlusions. Further development for ischemic stroke therapy is justified.
Animals↗
Prognostic significance of monthly weight fluctuations among older nursing home residents.
BACKGROUND: Although weight change in older persons has proven prognostic significance, it is not known whether monthly weights obtained by the clinical staff in long-term care institutions are reliable enough to be useful in identifying at-risk residents. The objective of this study was to determine whether an association exists between mortality risk and the intraresident variation in weight in long-term care institutions. METHODS: For this study, 900 nursing home residents with a recently identified nutritional problem from 96 long-term care facilities in 8 states were randomly selected. At study entry, nutritional, health status, and demographic data were extracted from the nursing home chart or the Minimum Data Set. Weights obtained by the nursing home staff were recorded at baseline and during each of the subsequent 6 months. Cox proportional hazards regression analysis was used to assess relationships between weight parameters and mortality risk during the 7 months of observation. RESULTS: During the study, 435 (48%) participants had at least 1 monthly weight that differed from the previous month's weight by > or =5%; 163 (18%) participants had this magnitude of a 1-month weight change more than once. By controlling for the linear trend (i.e., slope) of each residents' weight change between the first to the last weight, the average month-to-month residual variability in the resident's weights was calculated. This residual variability or "average random fluctuation" in weight from 1 month to the next was > or =2% in 229 (25%) participants and > or =3% in 82 (9%) participants. Despite the large random fluctuation in the residents' weights, weight loss was an important prognostic indicator. Those who lost > or =5% in any month had a 10-fold increased risk for death compared with those who gained weight (adjusted relative risk, 10.6; 95% confidence interval, 3.2 to 35.5). The average random fluctuation in weight was associated with an increased risk for death only at the upper 10th percentile for the population. CONCLUSIONS: Many nutritionally compromised elderly nursing home residents experience significant bidirectional fluctuations in their weight from month to month. How much of this variability is due to measurement error is not known. However, a weight loss of > or =5% in any month has important prognostic implications.
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Body weight change and mortality in a cohort of elderly patients recently discharged from the hospital.
OBJECTIVES: To evaluate the prognostic significance of weight change in frail elderly patients. DESIGN: Prospective study. SETTING: The general medical or surgical wards of a university-affiliated Department of Veterans Affairs hospital. PARTICIPANTS: Six hundred sixty randomly selected subjects aged 65 or older. MEASUREMENTS: At admission and discharge, each subject completed a standardized diagnostic evaluation, including demographic variables, and basic medical, functional, and nutritional assessments. Weights were recorded from hospital or clinic visits in the year before admission, during the current hospitalization, and after discharge for a median of 5.6 years. Average yearly intraindividual weight change was calculated using least-squares regression. Associations between intraindividual weight change and mortality were identified using Cox proportional hazards regression. RESULTS: During the study, 314 subjects (48%) died. A U-shaped association between weight change and mortality was observed. Those who were relatively weight stable (+/-1 kg/y) had the lowest mortality (28%). Compared with this group, the adjusted relative risks (ARR) of death for those who lost 1 or more to less than 3 kg/y and 3 or more kg/y were 2.14 (95% confidence interval (CI)=1.52-3.00) and 3.59 (95% CI=2.58-4.99), respectively. The ARR associated with a weight gain of 1 or more to less than 3 kg/y and 3 or more kg/y was 1.38 (95% CI=0.91-2.10) and 3.73 (95% CI=2.34-5.94), respectively. The amount of bidirectional weight fluctuation (estimated using coefficient of variance) was not significantly associated with mortality. CONCLUSION: For reasons that are not clear, elderly patients who gain 3 or more kg/y after hospital discharge are at nearly the same risk of mortality as those who lose this amount of weight.
APACHE↗
Proteasomal degradation of Runx2 shortens parathyroid hormone-induced anti-apoptotic signaling in osteoblasts. A putative explanation for why intermittent administration is needed for bone anabolism.
It is unknown why sustained elevation of parathyroid hormone (PTH) stimulates bone resorption, whereas intermittent administration stimulates bone formation. We show in mice that daily injections of PTH attenuate osteoblast apoptosis, thereby increasing osteoblast number, bone formation rate, and bone mass, but do not affect osteoclast number. In contrast, sustained elevation of PTH, achieved either by infusion or by raising endogenous hormone secretion with a calcium-deficient diet, does not affect osteoblast apoptosis but increases osteoclast number. Attenuation of apoptosis by PTH in cultured osteoblastic cells requires protein kinase A-mediated phosphorylation and inactivation of the pro-apoptotic protein Bad as well as transcription of survival genes, like Bcl-2, mediated by CREB (cAMP response element-binding protein) and Runx2. But, PTH also increases proteasomal proteolysis of Runx2. Moreover, the anti-apoptotic effect of PTH is prolonged by inhibition of proteasomal activity, by overexpressing a dominant negative form of the E3 ligase (ubiquitin-protein isopeptide ligase) that targets Runx2 for degradation (Smurf1), or by overexpressing Runx2 itself. The duration of the anti-apoptotic effect of PTH, thus, depends on the level of Runx2, which in turn is decreased by PTH via Smurf1-mediated proteasomal proteolysis. The self-limiting nature of PTH-induced survival signaling might explain why intermittent administration of the hormone is required for bone anabolism.
Animals↗
Occupational asthma symptoms and respiratory function among aerial pesticide applicators.
BACKGROUND: Pesticide exposure has been suggested as one causal factor for the rise in asthma prevalence. The goal of this investigation was to determine the effect of pesticide exposure on respiratory symptoms and lung function in workers with occupational exposure to pesticides. METHODS: A prospective, case-controlled study was conducted among pesticide aviators (AV) and community controls (Con). In Phase I, subjects completed an asthma survey and baseline spirometry. In Phase II, subjects reported symptoms, lung function monitoring, and pesticide exposure during two, 14-day periods. RESULTS: Phase I-Self-reported asthma and symptoms were similar among AV (n = 135) and Con (n = 118) with 4-6% prevalence reported but with higher rates among smokers. Baseline lung function was similar; although, a higher proportion of AV had forced expiratory volume in one second (FEV(1)) <80% predicted (8% vs. 2%, P = 0.02). Phase II-Self-reported symptoms were similar with 80% of AV (n = 50) and 73% of Con (n = 49) reporting no symptoms. Only 4% of AV and 6% of controls reported increased symptoms from baseline to spray season. Serial lung function did not differ between group and mean diurnal variation in peak expiratory flow improved in both groups between sampling times (AV 18% vs. 14%; Con 19% vs. 16%, P < 0.001). CONCLUSIONS: This study suggests that among workers with occupational pesticide exposure, asthma symptoms and lung function are similar to those of controls with only community-based exposure.
Adult↗
Microbubble-augmented ultrasound declotting of thrombosed arteriovenous dialysis grafts in dogs.
PURPOSE: Transcutaneous low-frequency ultrasound (LFUS) can effectively lyse clots in the presence of microbubbles. This study was designed to test the commercially available human albumin microspheres injectable suspension octafluoropropane formulation, Optison, to establish efficacy and assess US parameters of intensity and wave modes in a canine model of a thrombosed arteriovenous (dialysis) graft. MATERIALS AND METHODS: Arteriovenous grafts in five dogs were cannulated, temporarily ligated, and thrombosed. Different declotting techniques were randomized to treat nine groups. Control groups involved direct saline (4.5 mL) clot injection in 0.5-1.0-mL increments. One group underwent peripheral intravenous microbubble injection (13.5 mL). Six groups underwent direct incremental clot injection of 4.5 mL of microspheres with LFUS for 30 minutes in 3-5-minute increments with use of various intensity settings in continuous-wave and pulsed-wave (PW) modes. At each increment, angiography was used to grade flow, declotting, and overall success. RESULTS: One hundred four procedures showed success in all 24 high-intensity PW modes (1.2-2.0 W/cm(2)); only one of 20 control experiments was successful (P <.0001). Medium-intensity modes yielded intermediate success rates. Lowest-intensity direct-injection groups and intravenous and control groups ranked lower. Results at 30 minutes were better than at 15 minutes (P <.0001). CONCLUSIONS: LFUS with direct injection of microbubbles is effective in lysing moderate-sized clots and recanalizing thrombosed arteriovenous grafts. It best succeeds at the higher range of intensity settings tested in PW mode. Further development is justified.
Albumins↗
Microbubble potentiated ultrasound as a method of stroke therapy in a pig model: preliminary findings.
PURPOSE: Low-frequency ultrasound (LFUS) with intraarterial or intravenous microbubbles can recanalize thrombosed dialysis grafts and arteries. A similar method for declotting intracranial arteries in an animal model has been developed. MATERIALS AND METHODS: Swine underwent selective cerebral angiography, and 1 mL of 2-6 hour old clot was placed in one ascending pharyngeal artery and rete mirabile. This occluded the primary brain blood supply from the rete mirabile in the base of the skull. Human albumin octafluoropropane microbubbles were injected through the same catheter in 0.5-1.0-mL doses for a total of 4.5 mL in 21 minutes. Transcutaneous pulsed-wave 1-MHz ultrasound was administered through a temporal approach using 2.2 W/cm(2). Repeated angiography was performed through 24 minutes. Saline controls underwent an identical process on the opposite side. Declotting was graded on a scale of 0-4, and flow used the 0-3 thrombolysis in myocardial infarction (TIMI) scale. Success was defined as declotting of grade >/= 3 (>70% clearing) with flow of >/= 2. RESULTS: Seven pigs received 14 declotting sequences. Average clot age was 217 minutes. Average declotting score was 3.1, and flow was 2.1 for microbubbles and 1.4 and 0.1 for saline controls, P =.016 in each. Success occurred with microbubbles in six of seven attempts and in controls in zero of seven attempts, P =.031. CONCLUSIONS: LFUS with microbubble augmentation rapidly lyses intracranial clot and restores flow at ultrasound ranges similar to those required in humans. Further development of this possible acute stroke therapy is justified.
Animals↗
Protein-energy undernutrition and life-threatening complications among the hospitalized elderly.
OBJECTIVE: To determine whether elderly patients with protein-energy undernutrition at admission are at increased risk for subsequent life-threatening events after controlling for illness severity. DESIGN: Prospective cohort study. SETTING: University-affiliated Department of Veterans Affairs hospital. PATIENTS: Five hundred eighty-six nonterminal patients (mean age 74 +/- 6 [SD] years, 98% male, 86% white) with a length of stay of 3 days or more. MAIN OUTCOME MEASURES: Life-threatening complications. RESULTS: Subsequent to admission, 37 subjects (6.3%) experienced at least 1 life-threatening complication. All of the putative nutrition variables examined and many non-nutrition, illness severity measures were strongly correlated with the risk of a life-threatening complication by univariate analyses (P <.05 for all analyses). After controlling for illness severity, admission serum albumin, prealbumin, and cholesterol were no longer significantly correlated with the outcome. In contrast, weight loss (>5% within 6 months), body mass index, mid-arm circumference, and suprailiac skinfold thickness remained strong independent predictors. The adjusted relative risk of a life-threatening complication ranged from 2.9 (95% confidence interval [CI], 1.3 to 6.4) for a body mass index <22 kg/m2 to 7.1(95% CI, 2.0 to 25.7) for a suprailiac skinfold thickness in the lower tertile for the study population. The putative nutrition and illness severity variables were highly intercorrelated. CONCLUSIONS: There is a complex interrelationship between nutritional status, illness severity, and clinical outcomes among the hospitalized elderly. The serum secretory proteins and cholesterol are correlated with other indicators of illness severity and adverse outcomes, but may not be good markers of nutritional risk. In contrast, weight loss, a low body mass index, and other indicators of lean and fat mass depletion appear to place the patient at increased risk for adverse outcomes independent of illness severity. Whether it is possible to reverse such established nutritional deficits and reduce complication risk in the acute care setting remains to be determined.
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Undernutrition and risk of mortality in elderly patients within 1 year of hospital discharge.
BACKGROUND: The importance of undernutrition as a determinant of postdischarge mortality among hospitalized elderly people remains controversial. The purpose of this study was to investigate this issue. METHODS: The study included 660 elderly patients (85% white, 98% men, average age 73 +/- 6 years) discharged from a university-affiliated Department of Veterans Affairs Hospital, who were followed for 1 year. Associations between patient characteristics at hospital discharge and mortality were identified utilizing Cox Proportional Hazards Regression analysis. RESULTS: In the year following hospital discharge, 85 subjects (13%) died. After adjusting for illness severity (Acute Physiology and Chronic Health Evaluation II score) and functional status (Katz Index of Activities of Daily Living score), a body mass index (BMI) </=20 kg/m(2) was strongly associated with mortality (adjusted relative risk, [95% confidence interval] 1.83 [1.17-2.85]), as was more than 10% weight loss in the prior year (2.31 [1.35-3.94]), and weight as percent of usual weight (WPU) </=85% (1.78 [1.14-2.77]). Albumin </=30 g/l was only weakly associated with mortality (1.10 [0.67-1.81]). When all of the putative nutrition variables were included in a multivariable analysis with the two control variables, only BMI followed by WPU </=85% entered the model. Utilizing this model, the predicted probabilities of death at 1 year were calculated for the study subjects and for a hypothetical group of patients who were identical to the study subjects except they were assigned a BMI of 28 kg/m(2) and their WPU was 100%. Compared to 24% of the actual subjects, only 7% of the hypothetical well-nourished patients would have been classified as being at high risk for mortality (a 71% relative reduction). CONCLUSIONS: Older patients who have evidence of chronic body mass depletion are at significantly increased risk of mortality within the year following hospital discharge.
APACHE↗
Immunotherapy for recalcitrant warts in children using intralesional mumps or Candida antigens.
Intralesional injection of mumps and Candida skin test antigens has been shown to be effective in the treatment of warts. Warts are generally difficult to treat in children. To determine the efficacy of intralesional skin test antigen injection for the treatment of resistant warts in children, we treated 47 pediatric patients with one or more warts with intralesional injection of mumps or Candida skin test antigen into one wart. Twenty-two patients (47%) with resistant warts experienced complete resolution of treated warts. An average of 3.78 treatments were necessary. An additional 34% of children had a greater than 25% improvement in their warts. Sixty-eight percent of subjects with more than one wart also noted at least partial resolution (greater than 25% resolution) of untreated warts at distant sites, with 34% experiencing complete resolution. We concluded that intralesional injection of skin test antigens is an effective therapy for children who have recalcitrant, nongenital, cutaneous warts.
Adolescent↗