Membrane-associated inhibitor of DNA synthesis in senescent human diploid fibroblasts: characterization and comparison to quiescent cell inhibitor.

Cell membranes prepared from senescent human diploid fibroblasts (HDF) inhibited entry into S phase by 35% when added to the medium of replicating young HDF. This membrane-associated inhibitory activity was (i) sensitive to trypsin, heat, and periodate, which suggests that the inhibitor is a glycoprotein, and (ii) not able to inhibit DNA synthesis in simian virus 40-transformed HDF, which indicates that not all types of cells are sensitive to this inhibitor. Quiescent young HDF also have a surface membrane-associated inhibitor of DNA synthesis. A comparison of the senescent HDF and quiescent HDF inhibitor activities indicates that they may have the same chemical and physical nature and the same specific activity, but their regulation is different. The inhibitory activity of quiescent young HDF is abolished within 20 hr after refeeding with fresh serum-containing medium, whereas that of senescent HDF remains unchanged. Quiescent old HDF (two or three population doublings remaining) exhibit an intermediate response to serum with approximately two-thirds of the inhibitory activity abolished. The fraction of cells in S phase at 20-24 hr post-stimulation (37% in young HDF, 24% in old HDF, and 0% in senescent HDF) is inversely proportional to inhibitor levels. This suggests that inability to neutralize the inhibitory activity in response to serum stimulation could be involved in the inability of senescent HDF to enter S phase. Disappearance of the inhibitory activity from quiescent young HDF occurs late in G1 phase. Thus, the inhibitor may play a role in determining the length of the G0 to S phase transition in these cells.     

Technetium stannous pyrophosphate myocardial scintigrams in patients with chest pain of varying etiology.

Technetium-99m stannous pyrophosphate was utilized for myocardial imaging in 202 patients admitted to the hospital with chest pain of uncertain etiology. One hundred and one patients had clinical and evolved electrocardiographic and enzymatic evidence of acute myocardial infarction. Ninety-six of these 101 patients had increased myocardial uptake of the technetium stannous pyrophosphate and positive myocardial scintigrams; there was nearly precise correlation between the ECG and myocardial imaging localization of the area of infarction for acute transmural myocardial infarctions. In the five patients with negative myocardial images the scintigrams were obtained after seven or more days had elapsed following the myocardial infarction. In the remaining 101 patients no clinical, ECG, or enzymatic evidence of infarction developed; 92 of these patients had negative myocardial scintigrams. Seven of the remaining nine patients were admitted with "unstable angina pectoris", and despite the absence of diagnostic ECG and enzyme evolution each of these patients had faintly and diffusely positive myocardial scintigrams. The remaining two patients had positive myocardial scintigrams but no definite ECG or enzymatic evidence of acute myocardial infarction. Thus the technetium pyrophosphate imaging technique appears safe, inexpensive and to correlate well with ECG and enzyme identification of the presence of infarction and with ECG localization of myocardial infarction. In addition the positive myocardial scintigrams in some patients with "unstable angina" suggest that there may be limited myocardial necrosis that is ordinarily undetected by ECG and enzymes in these patients. The incidence of false positive and false negative scintigrams appears to be small.     

Personality differences among black, white, and Hispanic-American male heroin addicts on MMPI content scales

Used MMPI Content Scale scores (Wiggins, 1966) to assess personality differences among black, white, and Hispanic-American heroin addicts. Ss were 423 male veterans who volunteered for the first time for treatment between 1972 and 1979 to an inpatient Drug Dependence Treatment Program (DDTP) of a Veterans Administration Medical Center. Two hypotheses were tested: First, that minority group heroin addicts (blacks and Hispanics) will show better adjustment than majority group (white) heroin addicts; second, that Hispanic-American heroin addicts will evidence personality characteristics unlike those of either whites or blacks. Both hypotheses were confirmed. Results were interpreted as supporting cultural theories of substance abuse and providing implications for diagnosis and treatment of substance abuse disorders among minority ethnic groups.     

Does method of sternal repair influence long-term outcome of postoperative mediastinitis?

Background

Post-sternotomy mediastinitis reduces survival after cardiac surgery, potentially further affected by details of mediastinal vascularized flap reconstruction. The aim of this study was to evaluate survival after different methods for sternal reconstruction in mediastinitis.

Methods

Two hundred twenty-two adult cardiac surgery patients with post-sternotomy mediastinitis were reviewed. After controlling infection, often augmented by negative pressure therapy, muscle flap, omental flap, or secondary closure was performed. Outcomes were reviewed and survival analysis was performed.

Results

Baseline characteristics were similar. In-hospital mortality (15.7%) did not differ between groups. Secondary closure was correlated with negative pressure therapy and reduced length hospital of stay. Recurrent wound complications were more common with muscle flap repair. Survival was unaffected by sternal repair technique. By multivariate analysis, heart failure, sepsis, age, and vascular disease independently predicted mortality, while negative pressure therapy was associated with survival.

Conclusions

Choice of sternal repair was unrelated to survival, but mediastinal treatment with negative pressure therapy promotes favorable early and late outcomes.     

The Availability and Use of Out-of-Hospital Physiologic Information to Identify High-Risk Injured Children in a Multisite,Population-Based Cohort

Objective. The validity of using adult physiologic criteria to triage injured children in the out-of-hospital setting remains unproven. Among children meeting adult field physiologic criteria, we assessed the availability of physiologic information, the incidence of death or prolonged hospitalization, and whether age-specific criteria would improve the specificity of the physiologic triage step. Methods. We analyzed a prospective, out-of-hospital cohort of injured children aged ≤14 years collected from December 2005 through February 2007 by 237 emergency medical services (EMS) agencies transporting to 207 acute care hospitals (trauma and nontrauma centers) in 11 sites across the United States and Canada. Inclusion criteria were standard adult physiologic values: systolic blood pressure (SBP) ≤90 mmHg, respiratory rate < 10 or > 29 breaths/min, Glasgow Coma Scale (GCS) score ≤12, and field intubation attempt. Seven physiologic variables (including age-specific values) and three demographic and mechanism variables were included in the analysis. “High-risk” children included those who died (field or in-hospital) or were hospitalized > 2 days. The decision tree was derived and validated using binary recursive partitioning. Results. Nine hundred fifty-five children were included in the analysis, of whom 62 (6.5%) died and 117 (12.3%) were hospitalized > 2 days. Missing values were common, ranging from 6% (respiratory rate) to 53% (pulse oximetry), and were associated with younger age and high-risk outcome. The final decision rule included four variables (assisted ventilation, GCS score < 11, pulse oximetry < 95%, and SBP > 96 mmHg), which demonstrated improved specificity (71.7% [95% confidence interval (CI) 66.7–76.6%]) at the expense of missing high-risk children (sensitivity 76.5% [95% CI 66.4–86.6%]). Conclusions. The incidence of high-risk injured children meeting adult physiologic criteria is relatively low and the findings from this sample do not support using age-specific values to better identify such children. However, the amount and pattern of missing data may compromise the value and practical use of field physiologic information in pediatric triage.