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The article discusses a study which was aimed to evaluate the effect of training status on differences between trials of 1 repetition maximum (1 RM) measurement in women. The study was conducted o 10 women who completed 3 trials of 1RM chest and leg press. The study suggested that training status has a positive influence on the efficiency of maximal strength measurement.

Although a dose-response relationship between resistance training frequency and strength has been identified, there is limited research regarding the association between frequency and body composition. This study evaluated the effects of 3 vs. 4 d·wk(-1) of resistance training on body composition and strength in middle-aged women. Twenty-one untrained women (age 47.6 ± 1.2 years) completed 8 weeks of resistance training either 3 nonconsecutive days of the week using a traditional total-body protocol (RT3) or 4 consecutive days of the week using an alternating split-training protocol (RT4). The RT3 completed 3 sets of 8 exercises, whereas RT4 completed 3 sets of 6 upper body exercises or 6 sets of 3 lower body exercises. Both groups completed 72 sets per week of 8-12 repetitions at 50-80% 1 repetition maximum. Weekly training volume load was calculated as the total number of repetitions x load (kg) completed per week. Body composition was measured using air displacement plethysmography. At baseline and after 8 weeks of resistance training, there were no significant between-group differences. Both protocols resulted in significant increases in absolute lean mass (1.1 ± 0.3 kg; p = 0.001), body weight (1.02 ± 0.3 kg; p = 0.005), body mass index (0.3 ± 0.1 kg·m(-2); p = 0.006), strength (p < 0.001), and weekly training volume load (p < 0.001). Correlation analysis revealed that weekly training volume load was strongly and positively related to gains in lean mass (r = 0.56, p = 0.05) and strength (r = 0.60, p = 0.006). In these untrained, middle-aged women, initial short-term gains in lean mass and strength were not influenced by training frequency when the number of training sets per week was equated. [ABSTRACT FROM AUTHOR]

Determining the treatment plan and how to successfully manage a patient suffering from an acute ischemic stroke can be challenging for a registered nurse (RN) in the emergency department. Using a mnemonic in the treatment process assists in reducing medical errors and increases the likelihood of making positive clinical outcomes. Mnemonics sum up complex strategies into relevant information that can be comprehensible for users. The authors have created a mnemonic strategy to provide RNs in the emergency department with a structured approach to the pharmacotherapeutic strategies used in treating patients with an acute ischemic stroke. All guidelines used throughout the article are in concurrence., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Although left ventricular assist device (LVAD) improves functional capacity, on average LVAD patients are unable to achieve the aerobic capacity of normal healthy subjects or mild heart failure patients. The aim of this study was to examine if markers of right ventricular (RV) function influence maximal exercise capacity. This was a single-center prospective study that enrolled 20 consecutive HeartWare ventricular assist device patients who were admitted at the Freeman Hospital (Newcastle upon Tyne, United Kingdom) for a heart transplant assessment from August 2017 to October 2018. Mean peak oxygen consumption (Peak VO2) was 14.0 ± 5.0 ml/kg/min, and mean peak age and gender-adjusted percent predicted oxygen consumption (%VO2) was 40.0% ± 11.5%. Patients were subdivided into two groups based on the median peak VO2, so each group consisted of 10 patients (50%). Right-sided and pulmonary pressures were consistently higher in the group with poorer exercise tolerance. Patients with poor exercise tolerance (peak VO2 below the median) had higher right atrial pressures at rest (10.6 ± 6.4 vs. 4.3 mmHg ± 3.2; p = 0.02) and the increase with passive leg raising was significantly greater than those with preserved exercise tolerance (peak VO2 above the median). Patients with poor functional capacity also had greater RV dimensions (4.4 cm ± 0.5 vs. 3.7 cm ± 0.5; p = 0.02) and a higher incidence of significant tricuspid regurgitation (moderate or severe tricuspid regurgitation in five patients in the poor exercise capacity group vs. none in the preserved exercise capacity group; p = 0.03). In conclusion, echocardiographic and hemodynamic markers of RV dysfunction discriminate between preserved and nonpreserved exercise capacity in HeartWare ventricular assist device patients., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2020.)

Objective: There are pronounced racial and socioeconomic disparities in type 2 diabetes. Although "stress" as a general phenomenon is hypothesized to contribute to these disparities, few studies have objective measures of stress reactivity in diverse samples to test hypotheses about purported mechanisms. This study describes the rationale and baseline characteristics of a cohort designed to address the question: how does stress contribute to disparities in diabetes risk?, Methods: The Richmond Stress and Sugar Study recruited 125 adults at elevated risk of type 2 diabetes using a two-by-two sampling frame wherein non-Hispanic whites and African Americans (AAs) were each recruited from neighborhoods of higher and lower socioeconomic status (SES). Stress reactivity was assessed using the Trier Social Stress Test (TSST) and salivary cortisol. Analyses of variance and multilevel modeling were used to examine how stress reactivity varied both within and across race and neighborhood SES., Results: The mean (SD) age was 57.4 (7.3) years, 49% were female, 54% were AA or another racial/ethnic minority, and mean hemoglobin A1c level was in the prediabetes range (5.8%; range, 5.50%-5.93%). Living in a lower-SES neighborhood was associated with 16% (95% confidence interval [CI] = -0.04 to 34) higher pre-TSST cortisol, 8.4% (95% CI = -14 to -3) shallower increase in response to the TSST, and 1% (95% CI = 0.3 to 1.7) steeper decline post-TSST than living in the higher neighborhood SES. Post-TSST cortisol decline was 3% greater among AA compared with non-Hispanic whites. Race-by-SES interaction terms were generally small and nonsignificant., Conclusions: SES is associated with stress reactivity among adults at high risk of diabetes.

We sought to determine hemodynamic mechanisms of exercise intolerance in a group of patients with the HeartWare ventricular assist device (VAD) compared to a group of heart failure patients. Twenty VAD and 22 heart failure patients underwent symptom-limited active straight leg raising exercise during right heart catheterization with thermodilution (TD), and upright cycling cardiopulmonary stress testing with cardiac output measurement by inert gas rebreathing (IGR) method. The TD and IGR exercise cardiac indexes were higher in VAD compared with heart failure group (both P < 0.05), although there was only a borderline increase in peak exercise oxygen consumption (VO2) (P = 0.06). Baseline and exercise right heart catheterization pressures were not significantly different between the two groups. The only significant independent predictors of peak VO2 in the heart failure group were exercise heart rate and cardiac index (both P < 0.05). In contrast, for the VAD group only, resting pulmonary arterial wedge and pulmonary arterial mean pressures were independently related to peak VO2 (both P < 0.05). Thus, in heart failure, exercise cardiac index is an important limitation to exercise capacity, and VADs increase exercise cardiac index. However, in VAD patients, this only produces limited benefits as increased pulmonary and pulmonary wedge pressures limit increases in exercise capacity.

Left ventricular assist devices (LVADs) have become an established treatment for advanced heart failure, although with long-term support these patients are potentially exposed to serious complications. Our purpose was to assess the role of the neutrophil to lymphocyte ratio (NLR) in LVAD complications and to evaluate if higher values of NLR after 4-6 months on LVAD support (NLR 4&#95;6m) are associated with worse prognosis. All consecutive patients who received a HeartWare LVAD (N = 188, age 50 ± 13 years), as bridge to transplant from December 2009 to January 2018 were included. Neutrophil to lymphocyte ratio was recorded pre-LVAD, post-LVAD, after 4-6 months on support and in case of a first adverse event to occur after the 4-6 months NLR was recorded. Median NLR values were pre-LVAD 4.26 (interquartile range [IQR], 3.1-6.9), at 1 day postoperative 11.6 (IQR, 8.3-16.6), and NLR 4&#95;6m 4.4 (IQR, 3.0-6.4) (p < 0.001). Neutrophil to lymphocyte ratio increased significantly when patients had an infection, stroke, or pump thrombosis, as compared with the NLR 4&#95;6m (all p < 0.05). Patients with NLR 4&#95;6m ≥ median had higher rates of stroke and mortality. Survival time was shorter among patients with NLR 4&#95;6m ≥ 4.4 (log-rank test p = 0.006). Neutrophil to lymphocyte ratio 4&#95;6m was found to be predictive of increased mortality (area under the curve of 0.62, p = 0.007). After multivariate analysis, NLR 4&#95;6m remained independently associated with increased mortality (hazard ratio [HR] 1.67; 95% confidence interval [CI], 1.03-2.7; p = 0.037). Neutrophil to lymphocyte ratio 4&#95;6m values significantly increase in association with adverse events on LVAD support and are independently associated with mortality. This association suggests presence of inflammation adversely affects LVAD outcomes.

Background: It has been hypothesized that glutamatergic dysfunction may play a role in the development of obsessive compulsive disorder (OCD) and that glutamatergic modulation may ameliorate some of the OC symptoms. We evaluated the effectiveness of amantadine (AMN)- a weak, noncompetitive, antagonist of the N-methyl-D-aspartic acid (NMDA) receptor-as an adjunctive therapy to selective serotonin reuptake inhibitors (SSRIs), and its role in improving OC symptoms in cases refractory to SSRI pharmacotherapy alone., Methods: Eight patients (5 males and 3 females, aged 42.6 ± 13.1 years) that met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for OCD, scored above 20 points on Yale Brown Obsessive Compulsive Scale (Y-BOCS) and were unresponsive to at least one SSRI, completed an open label study of 6 weeks duration. AMN was added to the current stable SSRI regimen and baseline and endpoint changes in Y-BOCS, depression and anxiety levels were analyzed., Results: Significant reductions in total Y-BOCS (28 ± 4.5 vs. 18.8 ± 8.8; P < 0.01; df = 7; t = 2.36), Y-BOCS compulsion sub-scale (15.3 ± 3.2 vs. 10.6 ± 4.7; P < 0.02; df = 7; t = 2.36), and Y-BOCS obsession sub-scale (12.7 ± 3.3 vs. 8.1 ± 5; P < 0.05; df = 7; t = 2.36) scores were obtained at endpoint. The anxiety and depression levels remained unaltered., Conclusions: AMN adjunction to SSRI treatment may lead to a significant reduction in OC symptoms, supporting the hypothesis that transduction of the glutamate signal via NMDA receptor may play a role in OCD. A large scale, double-blind, placebo-controlled study is warranted to confirm our results.

Background: Comparison of a multimodal intervention WE CALL (study initiated phone support/information provision) versus a passive intervention YOU CALL (participant can contact a resource person) in individuals with first mild stroke., Methods and Results: This study is a single-blinded randomized clinical trial. Primary outcome includes unplanned use of health services (participant diaries) for adverse events and quality of life (Euroquol-5D, Quality of Life Index). Secondary outcomes include planned use of health services (diaries), mood (Beck Depression Inventory II), and participation (Assessment of Life Habits [LIFE-H]). Blind assessments were done at baseline, 6, and 12 months. A mixed model approach for statistical analysis on an intention-to-treat basis was used where the group factor was intervention type and occasion factor time, with a significance level of 0.01. We enrolled 186 patients (WE=92; YOU=94) with a mean age of 62.5 ± 12.5 years, and 42.5% were women. No significant differences were seen between groups at 6 months for any outcomes with both groups improving from baseline on all measures (effect sizes ranged from 0.25 to 0.7). The only significant change for both groups from 6 months to 1 year (n=139) was in the social domains of the LIFE-H (increment in score, 0.4/9 ± 1.3 [95% confidence interval, 0.1-0.7]; effect size, 0.3). Qualitatively, the WE CALL intervention was perceived as reassuring, increased insight, and problem solving while decreasing anxiety. Only 6 of 94 (6.4%) YOU CALL participants availed themselves of the intervention., Conclusions: Although the 2 groups improved equally over time, WE CALL intervention was perceived as helpful, whereas YOU CALL intervention was not used., Clinical Trial Registration: URL: http://www.controlled-trials.com. Unique identifier: ISRCTN95662526.

Targeted mutagenesis technology has been used to investigate the biological characteristics of genes. We incidentally observed a discrepancy in the size of the glucocorticoid receptor (GCR) between CD14 knockout (KO) mice and backcross controls. The CD14 KO mice were generated using 129S4/SvJae-derived J1 embryonic stem cells, C57BL/ 6J donor blastocysts, and C57BL/6J backcross strain. In this study, the extent of genomic heterogeneity of the CD14 KO mice, potentially affecting their phenotype, was characterized in comparison to C57BL/6J controls. There were polymorphic alleles of the GCR gene in CD14 KO and C57BL/6J mice: a tandem repeat of 8 CAGs and 17 CAGs in the transactivation domain, respectively. The subsequent finding of eight CAGs in all 129 substrains examined and colocalization of CD14 and GCR genes on the same contig on chromosome 18 suggested that the GCR allele in the J1 embryonic stem cell genome cosegregated with the targeted CD14 locus. Interestingly, all three clusters of the protocadherin family, central genes in determining neuronal networks, were mapped between the CD14 and GCR loci. Further analyses revealed numerous nonsynonymous coding single-nucleotide polymorphisms within the protocadherin family between CD14 KO and C57BL/6J mice. In addition, heterogeneous profiles of endogenous retroviruses, which constitute approximately 10% of the genome, were observed between them. These findings suggest that cosegregation of genes flanking the targeted locus leads to a substantial level of genetic heterogeneity in CD14 KO mice compared with their backcross controls. Phenotypic changes observed in some KO mice may not be as definitive as expected.

Many authors delay triple arthrodesis in skeletally immature patients secondary to the belief that such a surgery would cause excessive shortening in a foot that is often already short. In the current study, foot growth rates were compared between a group of skeletally immature patients (<11 years) and a group of more skeletally mature patients (>11 years) after triple arthrodesis. The average age at surgery in the skeletally immature group was 9.8 years, with a mean follow-up of 3.4 years, and the average age at surgery in the more skeletally mature group was 13.6 years, with a mean follow-up of 2.5 years. No statistically significant differences in length or height growth rates after triple arthrodesis were found between the two groups. The incidence of pseudoarthrosis and residual deformity in both groups was comparable with other studies in the literature. This study does not support the belief that triple arthrodesis to correct hindfoot deformity, instability, or relief of pain should be restricted to the older child.

Tibial osteotomies in children have been associated with a number of complications. A retrospective review of 116 children who had 129 tibial osteotomies was performed to assess these complications at our institution. Results showed that there were 35 cases of wound problems, 6 cases of recurrence/reoperation, 5 cases of delayed union, 2 cases with transient peroneal nerve palsy, 1 case of nonunion, and 1 case of mal-union. Patients having certain comorbidities had a higher frequency of complications. There were no significant differences between the location of the tibial osteotomy (proximal or distal) and the incidence of complication. External fixation was associated with a lower incidence of complications than the use of pins and casting. Although our results demonstrate an overall low complication rate, there is a significant association between complications and comorbid conditions. This highlights the need to recognize comorbidities preoperatively and the potential of increased postoperative complications.

In a retrospective review of 74 tibial osteotomies performed for Blount disease, the patients were divided into three groups based on age and treatment. Group A (26 osteotomies), 4 years old or younger, and group B (34 osteotomies), older than 4 years, were treated the same with osteotomy and crossed pins. Group C (14 osteotomies), older than 4 years, was treated with osteotomy and external fixator. At 6 years of follow-up, the recurrence of varus deformity was 46%, 94%, and 72% in groups A, B, and C, respectively. There was no correlation between recurrence of varus deformity and preoperative deformity angle or degree of surgical correction. Fixation with crossed pins or external fixator was not a factor. Surgery at 4 years old or younger and correction of the postoperative deformity angle in valgus may obviate recurrence of varus deformity in Blount disease at long-term follow-up.

Objective: Immune stimulation of CD4 lymphocytes is thought to enhance HIV-1 replication in vivo. Therefore, we sought to define the impact of clinical events identified as putative immune activators on the variability of plasma HIV-1 RNA levels in persons with CD4 cell counts greater than 500 x 10(6) cells/l., Design: We prospectively recorded clinical events and measured plasma HIV-1 RNA levels weekly for 24 weeks in 16 HIV-1-infected adults who were not receiving antiretroviral therapy and who had CD4 cell counts greater than 500 x 10(6) cells/l., Methods: Standard weekly interviews were conducted to capture potential immune activators (e.g., infections, immunizations, and allergic reactions). All plasma HIV-1 RNA levels were measured using the Amplicor HIV-1 Monitor assay (Roche Diagnostics, Branchburg, New Jersey, USA) according to the manufacturer's instructions., Results: Participants had remarkably stable viral loads during the 6 month study period. Infections were significantly more frequent during the 7 days prior to individual HIV-1 RNA measurements that exceeded the assay variation thresholds determined for this study (+/- 0.324 log) than during the comparable time periods preceding stable measurements (P = 0.023). As a group, the eight participants who had one to four HIV-1 RNA measurements that exceeded the thresholds experienced more infections and declining CD4 cell counts over the study course compared to the eight participants whose measurements all fell within the thresholds (P = 0.058 and 0.053 respectively)., Conclusions: Our study suggests that in untreated HIV-1-infected persons with CD4 cell count greater than 500 x 10(6) cells/l, viral load is generally quite stable, although acute minor infections are associated with transient fluctuations generally lasting no more than 1 week.

Expansion of the surveillance definition for AIDS in the United States in 1993 caused a substantial distortion in the trend in AIDS incidence, mainly because CD4-positive (CD4+) T-lymphocyte criteria were added to the definition. To evaluate trends in the rate at which HIV-infected persons develop the opportunistic illnesses listed in the AIDS surveillance definition (AIDS-OIs), we developed a procedure for estimating the incidence of these diseases. This estimate is based primarily on the probability distributions of the time from a CD4+ count in given ranges to the diagnosis of the first AIDS-OI. Our estimates of AIDS-OI incidence change by <4% during most calendar quarters during 1991 through 1995 if we also include the estimated effects of unreported AIDS-OIs among persons with AIDS reported based on the CD4+ criteria. Our procedure eliminates the transient effect of adding the CD4+ criteria to the AIDS surveillance definition and permits us to evaluate trends in the incidence of AIDS-OIs.

We used national AIDS surveillance data to characterize trends in the numbers and proportions of heterosexually acquired AIDS cases diagnosed from January 1988 through December 1995 among adults and adolescents. We adjusted for expansion of the 1993 AIDS surveillance case definition and for delays in reporting, and we redistributed cases initially reported without risk. The chi-square test for linear trend was used to analyze trends at the p < 0.01 level by half-year of diagnosis and by sex, age, race or ethnicity, geographic region of residence at diagnosis, and partner's HIV exposure risk. From 1988 through 1995, heterosexual contact accounted for 10% of all AIDS cases. Heterosexual contact increased the most rapidly of all HIV exposure modes, with increases found among men and women in all age groups; among blacks, whites, and Hispanics: and among persons living in all geographic regions of the country. Blacks and Hispanics accounted for 75% of all persons reported with AIDS attributed to heterosexual contact. Although heterosexual contact with an injection drug user (IDU) accounted for most cases until 1993, cases increased most rapidly among persons reporting heterosexual contact with an HIV-infected partner whose risk was not specified. Findings suggest continued growth of the heterosexual AIDS epidemic. Because of the disproportionate and increasing number of heterosexually acquired AIDS cases among blacks and Hispanics, black and Hispanic communities at risk for HIV infection should be considered a high priority for prevention and education programs specifically targeting heterosexually active adolescents and adults. Epidemiologic and behavioral research and prevention program evaluation are urgent public health priorities to better control and prevent the further spread of HIV among heterosexually active adults and adolescents.

While the use of the centrifugal vortex ECMO pump as an alternative to a roller-occlusion pump offers distinct advantages, unacceptable hemolysis may occur during its use in newborn infants. The authors studied 87 consecutive neonatal patients with respiratory failure supported with venoarterial ECMO using a centrifugal vortex pump. Baseline mean plasma free hemoglobin level for all patients during the first 48 hours of bypass was 31.3 +/- 3.1 md/dl. In 51 patients, an abrupt rise in the plasma free hemoglobin occurred. In 48 of 51 patients, the pump head alone was changed at 91.9 +/- 6.6 hours after initiation of bypass. Mean plasma free hemoglobin decreased to baseline values following pump head change. The authors could not determine any factors that distinguish the infants who developed hemolysis from those who did not. Changing only the pump head provides a simple approach to hemolysis during use of the centrifugal vortex pump on newborn infants.

Objective: Several small short-term intervention studies have suggested that beta-carotene supplementation in HIV-infected patients can increase the number of various immune cells including CD4 cells. This prospective double-blinded study was designed to investigate whether beta-carotene supplementation would result in this immuno-enhancement in a larger number of patients over a longer time period., Methods: HIV-positive patients were randomly assigned to receive either 60 mg beta-carotene orally three times daily or a matched placebo. In addition, all patients received a multivitamin supplement. Patients were evaluated at baseline, 1 month, and 3 months for T-cell quantitative subsets, natural killer cells, HIV p24 antigen, beta-carotene levels, complete blood counts and chemistry batteries. Body weights and Karnofsky scores were evaluated at each visit., Results: Seventy-two patients signed informed consent forms and entered the study. Except for serum beta-carotene concentration, there were no statistically significant differences (P < 0.05) between the treatment (60 mg beta-carotene three times daily and multivitamins) and placebo (placebo and multivitamins) groups at baseline or after either 1 or 3 months of treatment., Discussion: Earlier studies suggesting that beta-carotene supplementation increased levels of immune cells in HIV-infected patients were not replicated in this study. The addition of a multivitamin supplement to both arms of this study may have masked any difference between the two groups. However, on the basis of the results of this study, we would not recommend supplementation with high doses of beta-carotene for HIV-infected patients.

The article presents the role of advanced practice nurses as change agents in the clinical setting. Research utilization is needed to shape and form the basis of nursing practice. As change agents, the advanced practice nurses in one institution established a research-based minimal stimulation protocol for the very low-birth weight infant and implemented it using a video presentation. Knowledge of change theory, research utilization, and video production was necessary in making this project a success.

Dopamine agonists have been used with some success in treating cocaine addiction. However, both cocaine and psychostimulants have been reported to produce neurotoxic effects. We evaluated the effect of the stimulant diethylpropion on cognitive performance in a double-blind, placebo-controlled trial. Forty-six abstinent crack-cocaine users received either placebo, 25-mg, 50-mg, or 75-mg doses of diethylpropion. Patients were tested at baseline and again after 9-14 days of medication. There were no differences between placebo and medication groups on any test, indicating that, within the time frame studied, diethylpropion does not produce neurotoxic effects that can be detected with standardized neuropsychological tests.

Objective: Extracorporeal membrane oxygenation (ECMO) has been used with increasing frequency in the treatment of acute respiratory failure in pediatric patients. Our objective in this study was to test the hypothesis that ECMO improves outcome in pediatric patients with acute respiratory failure., Design: Multicenter, retrospective cohort analysis., Setting: Forty one pediatric intensive care units participated in the study under the auspices of the Pediatric Critical Care Study Group., Patients: All pediatric patients admitted to the participating institutions with acute respiratory failure during 1991 were included. Patients with congenital heart disease, contraindications to ECMO, or incomplete data were excluded, yielding a data set of 331 patients from 32 hospitals., Interventions: Conventional mechanical ventilation, high-frequency ventilation, and extracorporeal membrane oxygenation., Measurements and Main Results: Multivariate logistic regression analysis was used to identify factors associated with survival. In a second analysis, pairs of ECMO and non-ECMO patients, matched by severity of disease and respiratory diagnosis, were compared. The use of ECMO (p = .0082), but not the use of high-frequency ventilation, was associated with a reduction in mortality. Other factors independently associated with mortality included oxygenation index (p < .0001), Pediatric Risk of Mortality score (PRISM) (p < .0001) and the Paco2 (p = .045). In 53 diagnosis- and risk-matched pairs, there was a significantly lower mortality rate (26.4% vs. 47.2%; p < .01) in the ECMO-treated patients. When all patients were stratified into mortality risk quartiles on the basis of oxygenation index and PRISM score, the proportion of deaths among ECMO-treated patients in the 50% to 75% mortality risk quartile was less than half the proportion in the non-ECMO treated patients (28.6% vs. 71.4% p < .05)> No effect was seen in the other quartiles., Conclusions: The use of ECMO was associated with an improved survival in pediatric patients with respiratory failure. The lack of association of outcome with treatment in the ECMO-capable hospital or with another tertiary technology (i.e. high-frequency ventilation) suggests that ECMO itself was responsible for the improved outcome. Further studies of this procedure are warranted but require broad-based multi-institutional participation to provide sufficient statistical power and sensitivity to demonstrate efficacy.

Objective: Extracorporeal membrane oxygenation (ECMO) has been used with increasing frequency for respiratory failure that is unresponsive to conventional therapy. We examined the relationship between duration of ECMO and outcome to understand whether prolonged ECMO (duration of the procedure for > 14 days) was more commonly associated with futile therapy or eventual recovery., Design: A cohort study of all patients reported to the Pediatric ECMO Registry for Acute Respiratory Failure of the Extracorporeal Life Support Organization., Setting: Tertiary hospitals (n = 83) capable of providing extracorporeal support for pediatric patients., Patients: Children (n = 382) between the ages of 1 wk and 18 yrs of age with severe respiratory failure., Interventions: Extracorporeal membrane oxygenation., Measurements and Main Results: The death or live hospital discharge of ECMO-treated patients, together with the post-ECMO mechanical ventilation course, were examined as a function of duration of ECMO and of pre-ECMO respiratory status. The occurrence of complications and the causes of death were also noted. The criteria used to initiate ECMO, as well as the determination of the futility of further ECMO, were determined by local practice at individual centers. There were 382 patients treated with ECMO, of whom 184 (48%) survived. The proportional survival in the patients treated for the longest duration was similar to the overall group. The cause of death was given for 168 patients: 32 neurologic deaths; nine deaths due to ECMO complications; and 30 deaths due to nonpulmonary organ failure. There were 97 deaths due to elective ECMO termination; 80 of these deaths occurred after the determination of the futility of anticipating pulmonary recovery. The latter deaths occurred at widely varying durations of ECMO, with a median of 282 hrs. However, at that same duration, 47 eventual survivors (26% of all survivors) continued to receive ECMO. By discriminant analysis, the survival rate was independently related (r2 = .18; p < .0001) to peak ventilator inspiratory pressure before ECMO and duration of intubation before ECMO, patient age, and the occurrence of several complications., Conclusions: While the survival rate in pediatric patients receiving ECMO appears related to the severity of lung disease and to the occurrence of ECMO complications, the survival rate in patients treated with ECMO courses of > 2 wks was similar to the survival rate of patients treated for shorter periods of time. ECMO was terminated in some patients for pulmonary futility at durations of ECMO associated with survival in substantial numbers of patients in whom ECMO was continued.

Study Design: This was a cadaveric lumbar motion segment experiment., Objectives: To measure bending about the pars interarticularis during simulated flexion and extension movements, with and without high compressive forces. This was designed to indicate which activities are most likely to cause spondylolysis., Summary of Background Data: The mechanical etiology of spondylolysis is controversial., Methods: Motion segments were loaded to simulate: A, full flexion; B, full extension; C, high compression in flexed posture, and D, high compression in lordotic posture. Bending of the inferior articular processes about the pars was measured in the sagittal plane, using a two-dimensional "MacReflex" infrared motion analysis system., Results: In full flexion, tension in the intervertebral ligaments bent the processes forward and down (by 3.25 degrees +/- 3.07 degrees), whereas in the loading conditions B, C, and D, inter-facet compressive forces caused the processes to bend backward and upward, by 2.24 +/- 2.48 degrees, 0.40 +/- 0.23 degrees, and 0.74 +/- 0.56 degrees respectively., Conclusions: Activities that involve alternating flexion and extension movements cause large stress reversals in the pars and pose the greatest threat of spondylolysis. Compressive loading has little effect.

Objectives: Homeless persons have an increased risk of HIV infection because of a high prevalence of HIV-related risk behaviors. These include drug use, sexual contact with persons at risk for HIV infection, and the exchange of sex for drugs. The objectives of this investigation were to describe HIV seroprevalence rates in homeless adults and runaway youth., Methods: In 1989, the Centers for Disease Control and Prevention began collaboration with state and local health departments to conduct HIV seroprevalence surveys in homeless populations. Unlinked HIV seroprevalence surveys were conducted in 16 sites; 11 provided medical services primarily to homeless adults, and five to runaway youth aged < 25 years., Results: From January 1989 through December 1992, annual surveys were conducted in 16 sites in 14 cities. Site-specific seroprevalence rates ranged from 0-21.1% (median, 3.3%). Among homeless adults in three sites, rates were higher among men who had sex with other men and those who injected drugs than among persons with other risk exposures (28.9 versus 5.3%). In general, rates were higher for heterosexual men than for women and higher among African Americans than whites. In sites providing services to homeless youth, HIV seroprevalence rates ranged from 0-7.3% (median, 2.3%)., Conclusions: These data indicate that HIV infection among homeless adults and runaway youth is an important public health problem. HIV prevention and treatment should be integrated into comprehensive health and medical programs serving homeless populations.