Single Molecule Characterization of UV-Activated Antibodies on Gold by Atomic Force Microscopy.

The interaction between proteins and solid surfaces can influence their conformation and therefore also their activity and affinity. These interactions are highly specific for the respective combination of proteins and solids. Consequently, it is desirable to investigate the conformation of proteins on technical surfaces, ideally at single molecule level, and to correlate the results with their activity. This is in particular true for biosensors where the conformation-dependent target affinity of an immobilized receptor determines the sensitivity of the sensor. Here, we investigate for the first time the immobilization and orientation of antibodies (Abs) photoactivated by a photonic immobilization technique (PIT), which has previously demonstrated to enhance binding capabilities of antibody receptors. The photoactivated immunoglobulins are immobilized on ultrasmooth template stripped gold films and investigated by atomic force microscopy (AFM) at the level of individual molecules. The observed protein orientations are compared with results of nonactivated antibodies adsorbed on similar gold films and mica reference samples. We find that the behavior of Abs is similar for mica and gold when the protein are not treated (physisorption), whereas smaller contact area and larger heights are measured when Abs are treated (PIT). This is explained by assuming that the activated antibodies tend to be more upright compared with nonirradiated ones, thereby providing a better exposure of the binding sites. This finding matches the observed enhancement of Abs binding efficiency when PIT is used to functionalize gold surface of QCM-based biosensors.

Validity of the Michigan Alcoholism Screening Test (MAST) for the detection of alcohol-related problems among male geriatric outpatients.

Alcoholism is a frequent and underdiagnosed mental health problem of later life. Its detection often relies on the use of screening instruments such as the Michigan Alcoholism Screening Test (MAST). The authors investigated the properties of the scale in a sample of 122 older adults recruited from a geriatric outpatient service in São Paulo, Brazil. Thirty-five subjects met criteria for the diagnosis of alcohol abuse or dependence according to DSM-III-R. The cutoff point 4/5 was associated with a sensitivity of 91.4%, specificity of 83.9%, and positive and negative predictive values of 69.6% and 96.0%, respectively. These results indicate that the MAST is a good screening test for the detection of alcohol abuse and dependence in an elderly male population and that the MAST should be used in combination with a questionnaire assessing the frequency/quantity of alcohol consumption to optimize the detection of cases and characterize their current drinking patterns.

Alcoholism in a geriatric outpatient clinic of São Paulo-Brazil.

Alcohol abuse and dependence are an increasing health problem among the elderly, but there is only scanty information about their prevalence and associated risk factors in developing countries. The authors set out to evaluate the prevalence and associated clinical/demographic features of alcoholism in a sample of male elderly subjects attending a Geriatric Primary Health Outpatient Clinic in a State University Hospital in the City of São Paulo-Brazil. Three hundred four patients were assessed with the Brazilian version of the Michigan Alcoholism Screening Test and a semistructured questionnaire designed to investigate associated features. Lifetime alcoholism was present in 15.1% of the sample, although only 4.3% were active drinkers. Patients classified as "cases" were younger than their nonalcoholic counterparts (70.61 vs. 73.31), and there was a mild, though not significant, excess of Blacks and Mulattos among the former (32.6% vs. 15.9%). Cases were also more likely to rely on their family for financial support (59.0% vs. 43.5%) and to acknowledge a positive family history of alcoholism (51.4% vs. 31.2%). Alcohol abuse or dependence was further associated with heavy smoking (58.7% vs. 44.0%). The authors concluded that alcoholism in this Brazilian elderly sample was likely to be associated with an earlier age at onset of medical problems, financial dependence, Black/Mulatto race, smoking, and positive family history of alcohol abuse/dependence. The authors suggest that the use of standardized methods of assessment of alcoholism in general medical settings may increase the detection of cases and contribute to improved health measures for the management of these patients.

[Transesophageal echocardiography in patients with chronic atrial fibrillation and cerebral ischemia]. / Ecocardiografia transesofagea in pazienti con fibrillazione atriale cronica e malattia ischemica cerebrale.

The authors wanted to verify the possibility of discovering, by means of transesophageal echocardiography, cardiac causes that can't be clearly shown with 2D echocardiography, in patients who suffered a cerebral ischaemic pathology and who had a cronic atrial fibrillation. The left atrial appendage is not well visualized by the 2D echocardiographic approach. Transesophageal echocardiography has been shown to be superior to transthoracic imaging in the evaluation of the mass lesions in the left atrium and his appendage and often the best visualization of the mitral valve leaflets and aortic semilunar cusps.