Relationship of numbing to alexithymia, apathy, and depression.

The present study assessed the relationship between numbing and three associated conditions of alexithymia, apathy, and depression, utilizing data collected on 353 Vietnam combat veterans diagnosed with Posttraumatic Stress Disorder from in- and out-patient settings and an outreach center at various Department of Veterans Affairs Medical centers. All subjects completed four self-report measures: the Glover Numbing Scale, the Beck Depression Inventory, the Apathy Evaluation Scale, and the Toronto Alexithymia Scale-20. The correlation matrix indicated that scores on the four measures were moderately to highly correlated. Principal components analysis with a varimax rotation indicated a five-factor solution that provided evidence for the factorial validity of each of the constructs assessed. Results of the factor analysis of items from the four measures were consistent with numbing being a separate and distinct construct from alexithymia, apathy, and depression. In general, results indicated that all constructs measured were separate and distinct from one another.

Characterization of the "helix clamp" motif of HIV-1 reverse transcriptase using MALDI-TOF MS and surface plasmon resonance.

A helix-turn-helix motif in the crystal structure of human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) was proposed to be a conserved nucleic acid binding domain among several nucleotide polymerizing enzymes (Hermann, T.; Meier, T.; Götte, M.; Heumann, H. Nucleic Acids Res. 1994, 22, 4625-4633). The sequence of this domain is homologous to 259KLVGKL-(X)16KLLR284 of HIV-1 RT, which acts as a "helix clamp" grasping the template-primer (T-P) complex. We characterized the helix clamp motif using MALDI-TOF MS and surface plasmon resonance (BIAcore). Our studies showed that the "helix clamp" has a nucleic acid binding function that may not be sequence specific. This evidence suggests that ionic interactions between the helix clamp and oligonucleotide backbone are not solely responsible for binding. Secondary and tertiary structures of the protein may also play a significant role in nucleic acid binding. The association and dissociation constants, ka and kd, for the binding of single-stranded oligonucleotide to the helix clamp were determined to be 7.03 x 10(3) M(-1) s(-1) and 1.22 x 10(3) s(-1), respectively.

Severity of symptoms of depression and anxiety as predictors of duration of psychotherapy.

The present study explored predictors of the duration of therapy exclusive of outcome utilizing data on 77 patients at St. John's University Center for Psychological Services. Measures of time in therapy were the total number of sessions attended and the number of sessions attended within the first six months of therapy. A bivariate Pearson product-moment correlation matrix was constructed, comprised of measures for time in therapy, severity of symptom measures, treatment modality (psychodynamic or cognitive-behavioral), age, and sex. There was a significant correlation between scores on state anxiety and the total number of sessions as well as between scores on state anxiety and number of sessions attended within six months, but no other correlations between measures of severity of symptoms and time in therapy were significant (p > .05). The results indicate that severity of symptoms does not significantly predict the duration of therapy.

Comprehensive two-dimensional high-performance liquid chromatography for the isolation of overexpressed proteins and proteome mapping.

A two-dimensional liquid chromatographic system is described here which uses size-exclusion liquid chromatography (SEC) followed by reversed-phase liquid chromatography (RPLC) to separate the mixture of proteins resulting from the lysis of Escherichia coli cells and to isolate the proteins that they produce. The size-exclusion chromatography can be conducted under either denaturing or nondenaturing conditions. Peaks eluting from the first dimension are automatically subjected to reversed-phase chromatography to separate similarly sized proteins on the basis of their various hydrophobicities. The RPLC also serves to desalt the analytes so that they can be detected in the deep ultraviolet region at 215 nm regardless of the SEC mobile phase used. The two-dimensional (2D) chromatograms produced in this manner then strongly resemble the format of stained 2D gels, in that spots are displayed on a X-Y axis and intensity represents quantity of analyte. Following chromatographic separation, the analytes are deposited into six 96-well (576 total) polypropylene microtiter plates via a fraction collector. Interesting fractions are analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) or electrospray mass spectrometry (ESI/MS) depending on sample concentration, which both yield accurate (2 to 0.02%) molecular weight information on intact proteins without any additional sample preparation, electroblotting, destaining, etc. The remaining 97% of a fraction can then be used for other analyses, such Edman sequencing, amino acid analysis, or proteolytic digestion and sequencing by tandem mass spectrometry. This 2D HPLC protein purification and identification system was used to isolate the src homology (SH2) domain of the nonreceptor tyrosine kinase pp60c-src and beta-lactamase, both inserted into E. coli, as well as a number of native proteins comprising a small portion of the E. coli proteome.

Platelet activation in whole blood by artificial surfaces: identification of platelet-derived microparticles and activated platelet binding to leukocytes as material-induced activation events.

Because the lack of thromboresistant vascular biomaterials is in part due to platelet activation, we have attempted, by using fluorescence-activated flow cytometry, to fully characterize the platelet population after in vitro material contact with whole blood. We have used a very simple, near-physiologic system whereby whole blood, anticoagulated with D-phenylalanyl-L-prolyl-arginyl chloromethyl ketone (thrombin inhibitor), contacts materials for 1 hour at 37 degrees C, under low shear. Unlike other tests of platelet compatibility that focus on adherent platelets, this assay evaluates the platelets in the whole blood drained from the tube (1.57 mm internal diameter, 25 cm length) after material contact. We demonstrate for the first time significant materials-induced microparticle formation. One-hour contact with Silastic, polyethylene, and polyvinyl alcohol hydrogel surfaces lead to 30 +/- 1, 33 +/- 4, and 43 +/- 4 x 10(9) microparticles/L, respectively, whereas resting blood samples contained only 10 +/- 1 x 10(9) microparticles/L. In addition, significant increases in activated platelet(s) binding to neutrophils/monocytes after material contact were noted for all surfaces tested. For polyvinyl alcohol hydrogel surfaces a greater than 500% increase in the fluorescent intensity over that of resting whole blood was attained. The addition of monoclonal antibodies to GPIIb/IIIa (A2A9), the tetrapeptide adhesion ligand RGDS (arginine-glycine-aspartate-serine), or the calcium ion chelator ethyleneglycol-bis-(B-aminoethyl-ether)- N,N,N',N'-tetraacetic acid to the whole blood before material contact fully inhibited all platelet reactivity noted for all surfaces--platelet microparticles, platelet P-selectin expression, loss of platelets from bulk, and the formation of platelet/leukocyte aggregates--thereby indicating that material-induced platelet activation is a calcium-dependent process involving GPIIb/IIIa receptors.