Biomedical subjects

Jose Barbosa

Publications and source records attributed to Jose Barbosa.

4 recordsLinked to original sources

PubMed2005

Structural requirements for steady-state localization of the vesicular acetylcholine transporter.

The vesicular acetylcholine transporter (VAChT) regulates the amount of acetylcholine stored in synaptic vesicles. However, the mechanisms that control the targeting of VAChT and other synaptic vesicle proteins are still poorly comprehended. These processes are likely to depend, at least partially, on structural determinants present in the primary sequence of the protein. Here, we use site-directed mutagenesis to evaluate the contribution of the C-terminal tail of VAChT to the targeting of this transporter to synaptic-like microvesicles in cholinergic SN56 cells. We found that residues 481-490 contain the trafficking information necessary for VAChT localization and that within this region L485 and L486 are strictly necessary. Deletion and alanine-scanning mutants lacking most of the carboxyl tail of VAChT, but containing residues 481-490, were still targeted to microvesicles. Moreover, we found that clathrin-mediated endocytosis of VAChT is required for targeting to microvesicles in SN56 and PC12 cells. The data provide novel information on the mechanisms and structural determinants necessary for VAChT localization to synaptic vesicles.

Amino Acid Sequence↗

PubMed2002

Measuring anxiety: parent-child reporting differences in clinical samples.

This study examines parent-child reporting differences for childhood anxiety in normal controls (n = 16) and in children with diagnosed anxiety disorders (ANX; n = 15), attention-deficit hyperactivity disorder (ADHD; n = 15), and comorbid ANX and ADHD (n = 16). Correspondence between child reports of anxiety on two self-report inventories and diagnosis based on structured parent interview was assessed for all four groups. Parent-child agreement did not appear to be measurement dependent but did differ by diagnostic group, with poorer agreement for clinical groups. Though needing replication, these findings suggest that it is inadvisable to rely exclusively on self-report measures when assessing childhood anxiety, especially in clinical populations. Such measures can be useful in monitoring clinical progress, however, provided parent and child reports are examined separately.

Anxiety↗

PubMed2002

Declining beta-cell function in type 2 diabetes: 5-year follow-up and immunologic studies of the population of Wadena, MN.

The aim of the study was to describe 5-year changes in meal-stimulated pancreatic insulin reserve in adults with normal and impaired glucose tolerance (NGT, IGT) and diabetes, with or without islet-related antibodies. This was a 5-year follow-up of 270 residents of Wadena, MN, of northern European origin, with good kidney function, defined as creatinine clearance greater than 60 mL/min/1.73 m(2). The subjects comprised a population-based sample originally studied in 1986 to 1987. Urine C-peptide (CP), in a 260-minute collection, was the integrated measure of insulin secretion; Ensure-Plus (Ross, Columbus, OH) was the liquid meal. Islet cytoplasmic antibodies (ICA), insulin autoantibodies (IAA), and glutamate decarboxylase antibodies (GAD65ab) were measured. In 182 subjects with NGT, there was no mean within-subject change in urine CP over 5 years (P =.34). In 41 subjects with impaired GT (IGT), there was a moderate, but nonsignificant, increase in mean CP, and 6 (15%) subjects increased. In 37 type 2 diabetic subjects not taking insulin (type 2-No Ins), who had a mean diabetes duration at the 5-year examination of 9.6 +/- 6.3 years, there was a 21% decrease in mean urine CP (P =.012), attributable mostly to a major drop in 8 of the 37 subjects (22%). Islet-related antibody tests were mostly negative; GAD65ab positivity was related to CP decline only among insulin-taking subjects. In summary, in Wadena adults, meal-stimulated urine CP was stable or increased over 5 years in subjects with NGT and IGT, but CP decreased significantly in about one fifth of type 2-No Ins subjects, with no relation to antibody test results.

Adult↗

PubMedDate not supplied

Combining multispectral polarized light imaging and confocal microscopy for localization of nonmelanoma skin cancer.

Multispectral polarized light imaging (MSPLI) enables rapid inspection of a superficial tissue layer over large surfaces, but does not provide information on cellular microstructure. Confocal microscopy (CM) allows imaging within turbid media with resolution comparable to that of histology, but suffers from a small field of view. In practice, pathologists use microscopes at low and high power to view tumor margins and cell features, respectively. Therefore, we study the combination of CM and MSPLI for demarcation of nonmelanoma skin cancers. Freshly excised thick skin samples with nonmelanoma cancers are rapidly stained with either toluidine or methylene blue dyes, rinsed in acetic acid, and imaged using MSPLI and CM. MSPLI is performed at 630, 660, and 750 nm. The same specimens are imaged by reflectance CM at 630, 660, and 830 nm. Results indicate that CM and MSPLI images are in good correlation with histopathology. Cytological features are identified by CM, and tumor margins are delineated by MSPLI. A combination of MSPLI and CM appears to be complementary. This combined in situ technique has potential to guide cancer surgery more rapidly and at lower cost than conventional histopathology.

Basal Cell Carcinoma↗