Phacoemulsification in review: Optimization of cataract removal in an in vitro setting

Phacoemulsification, initially used in the late 1960s, continues to be the standard of care for cataract removal. An animal model was developed so that, in a controlled research setting, all the various machines, handpieces, tips, and settings could be investigated. As a general rule, the higher power, vacuum, and aspiration settings lead to optimally efficient phacoemulsification. In addition, both new phacoemulsification platforms and newly developed devices have been shown to improve efficiency. As a result, we recommend that the integration of these recent developments should be considered in future investigations.     

Left ventricular function at high altitude examined by systolic time intervals and M-mode echocardiography

To better understand the effects of high-altitude hypoxia on cardiac performance, healthy lowlandresiding volunteers were studied in 2 groups: 10 subjects after acute ascent to 12,500 ft (3,810 m) (acute group) and 9 subjects after chronic exposure for 6 weeks to 17,600 ft (5,365 m) and 11,000 ft (3,353 m) (chronic group). Systolic time intervals and M-mode echocardiograms were recorded at low and high altitudes. Heart rate was 21% greater at high altitude for all subjects. Preejection period/left ventricular ejection time (PEP/LVET) increased by 16% in the acute group and by 22% in the chronic group. Heart size was smaller at high altitude in both groups, with left atrial and left ventricular (LV) diameters decreasing by 10 to 12%. These changes were statistically significant (p ≤ 0.01). Despite the increase in PEP/LVET, echocardiographic measurements of LV function (percent fractional shortening and mean normalized velocity of circumferential fiber shortening) remained normal. LV isovolumic contraction time was shorter at high altitude, suggesting heightened, rather than depressed, contractility. LV function does not appear to deteriorate at high altitude. Alterations in systolic time intervals probably result from decreased preload, as reflected by smaller heart size, rather than from heart failure or depressed LV contractility.     

German validation of the Conners Adult ADHD Rating Scales-self-report (CAARS-S) I: Factor structure and normative data

Background

Attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood. Instruments for diagnosing ADHD in childhood are well validated and reliable, but diagnosis of ADHD in adults remains problematic. Attempts have been made to develop criteria specific for adult ADHD, resulting in the development of self-report and observer-rated questionnaires. To date, the Conners Adult ADHD Rating Scales (CAARS) are the international standard for questionnaire assessment of ADHD. The current study evaluates a German version of the CAARS self-report (CAARS-S).

Methods

Eight hundred and fifty healthy German control subjects were recruited to fill out the CAARS-S and to answer questions on sociodemographic variables. Explorative and confirmative factor analyses were conducted to obtain the factor structure for the German model and to replicate the factor structure of the original American model. Analyses on gender, age, and education level were calculated for normative data.

Results

The explorative factor analysis of the German sample results in a six-factor solution that explained 52% of the variance. A confirmative analysis that was based on the 42 items of the original American model showed a high model-fit. Analyses of normative data showed significant influences of age, gender, and education level on the emerging subscales.

Conclusion

Even though the explorative factor analysis yields a solution different from the American original, the confirmative factor analysis results in such a high model-fit that use of the American version is justified with respect to international multicenter studies, for which this instrument will be highly valuable.     

Membrane-associated proteins of T4-infected Escherichia coli

During the prereplicative period after the infection of Escherichia coli by phage T4, more than 50 proteins are synthesized. Many of them have been identified with their corresponding genes. Among them, at least 13 are selectively enriched in the membrane preparation. They include the products of the two rII genes, genes 39, 52 (DNA-delay), and others not yet identified. The majority of these proteins (90%) are extractable by the detergent, sarkosyl, and are possibly associated with the inner or cytoplasmic membrane. Based on their electrophoretic migration in SDS-polyacrylamide gels and on their tryptic fingerprints, these proteins are found to be phage induced. Two of the newly synthesized proteins that are selectively enriched in the cell wall or outer envelope fraction are found to be identical with two envelope proteins of the host cell. They are continually synthesized after phage infection although general host protein synthesis is shut off.