Cytogenetic studies of familial and sporadic Alzheimer disease

We present cytogenetic findings in 7 familial and 5 sporadic Alzheimer disease (AD) patients and 34 unaffected relatives, spouses, and normal controls. Our study was prompted by reports of increased chromosome abnormalities in patients and family members at risk for AD. Coded peripheral blood chromosome preparations were evaluated for aneuploidy, aberration rates, and banding patterns. Statistical analyses of our results showed no increase in aneuploidy or aberrations in AD patients, their relatives, or normals. Chromosome loss or gain in aneuploid cells was not specific except in two individuals. These two older persons studied, one with AD and one unaffected, were observed to have increased sex chromosome aneuploidy. This finding was attributed to aging and was not considered to be an effect of AD.     

Verapamil preserves myocardial contractility in the hereditary cardiomyopathy of the Syrian hamster

We attempted to alter the inherited myocardial damage and loss of contractility of the cardiomyopathic Syrian hamster (strain U-MX7-1) by giving cardiac drugs that altered intracellular calcium and myocardial workload. Thirty-seven 21-day-old cardiomyopathic and thirty-seven 21-day-old normal hamsters were divided into five groups each: verapamil-, propranolol-, digoxin-, hydralazine-, and saline-injected. On their 90th day of life, the hamsters were killed. Of the five cardiomyopathic groups, only verapamil reduced myocardial damage. When both "control" and cardiomyopathic hamsters were treated with saline, digoxin, or propranolol, the cardiomyopathic hamsters had significantly less contractile force, maximal rate of force development, and maximum velocity of unloaded shortening. When both groups were treated with verapamil or hydralazine, there were no significant group differences in the indices of contractility. However, when saline-treated cardiomyopathic hamsters were compared with drug-treated cardiomyopathic hamsters, only verapamil preserved myocardial contractility. There was also a weak correlation between the Vmax and the actin-activated ATPase activity of the cardiomyopathic hamsters (r = 0.63, P less than 0.001). We conclude that verapamil helped protect the myocardium of genetically cardiomyopathic hamsters against structural damage, and helped preserve myocardial contractility.     

Central Venous Catheter Protective Connector Caps Reduce Intraluminal Catheter-Related Infection

BackgroundCentral line-associated blood stream infection (CLABSI) rates in adult care intensive care units have been decreasing across the board. However, we continued to see just a few infections in patients whose catheters are in for >4 days. Therefore, we looked at infections associated with intraluminal contamination to help reduce our infection rate.MethodsA protective cap trial was developed and implemented in 2 intensive care units. All of the central venous catheter and intravenous tubing access valves were covered with a protective cap saturated with alcohol. This intervention eliminated the need to wipe off intravenous access points with an alcohol swab. The study was done as a nonrandomized prospective trial occurring March 1, 2011 through February 29, 2012.ResultsDuring 2010, there were 4 CLABSI-related infections. By the end of the trial, we had incurred 1 catheter-associated blood stream infection. CLABSI rate reduced from 1.9 in 2010 to 0.5 during the 1-year trial period.ConclusionsThe implementation of the port protector cap system resulted in lower infection rates compared with an alcohol swab technique. Our results indicate that consistent use of the caps in tandem with strict compliance does influence CLABSI rates.     

CD4-T-cell antigen receptor complexes on human leukemia T cells.

CD4 and T-cell antigen receptor (TCR) comodulate from the surface of human and murine T cells following exposure to monoclonal anti-CD4 or anti-TCR. This comodulation may occur because expression of CD4 and TCR is regulated by similar transmembrane signals or because CD4 and TCR are physically associated. To study multimolecular assemblies on the plasma membrane, we developed a flow cytometric method for detecting singlet-singlet energy transfer between fluorescein isothiocyanate (FITC)- and tetramethylrhodamine isothiocyanate (TRITC)-conjugated monoclonal antibodies as sensitized TRITC emission on intact, single cells. Using this procedure, we detected CD4-TCR complexes on the surface of the transformed human leukemia T cells, HPB-ALL, in the absence of stimulation. More than one CD4 were found in association with one TCR. CD4-TCR complexes were not in rapid equilibrium with free CD4 and free TCR, and they were not induced by the dye-labeled anti-CD4 or anti-TCR.