Role of endothelin in the exercise intolerance of chronic heart failure

In conclusion, plasma levels of the endothelialderived vasoconstrictor endothelin-1 (but not those of other neurohormonal vasoconstrictor factors), measured during exercise correlated closely with objective variables of exercise capacity in patients with heart failure. These findings suggest that endothelin-1 may contribute to exercise intolerance in patients with heart failure, perhaps by limiting the ability of the peripheral vasculature to dilate during exercise.     

4E-binding protein phosphorylation and eukaryotic initiation factor-4E release are required for airway smooth muscle hypertrophy

The molecular mechanisms of airway smooth muscle hypertrophy, a feature of severe asthma, are poorly understood. We previously established a conditionally immortalized human bronchial smooth muscle cell line with a temperature-sensitive SV40 large T antigen. Temperature shift and loss of large T cause G1-phase cell cycle arrest that is accompanied by increased airway smooth muscle cell size. In the present study, we hypothesized that phosphorylation of eukaryotic initiation factor-4E (eIF4E)-binding protein (4E-BP), which subsequently releases eIF4E and initiates cap-dependent mRNA translation, was required for airway smooth muscle hypertrophy. Treatment of cells with chemical inhibitors of PI 3-kinase and mammalian target of rapamycin blocked protein synthesis and cell growth while decreasing the phosphorylation of 4E-BP and increasing the binding of 4E-BP to eIF4E, consistent with the notion that 4E-BP1 phosphorylation and eIF4E function are required for hypertrophy. To test this directly, we infected cells with a retrovirus encoding a phosphorylation site mutant of 4E-BP1 (AA-4E-BP-1) that dominantly inhibits eIF4E. Upon temperature shift, cells infected with AA-4E-BP-1, but not empty vector, failed to undergo hypertrophic growth. We conclude that phosphorylation of 4E-BP, eIF4E release, and cap-dependent protein synthesis are required for hypertrophy of human airway smooth muscle cells.     

Intrathyroidal accumulation of T cell phenotypes in autoimmune thyroid disease.

In this study we have correlated peripheral T cell subset phenotypes with intrathyroidal lymphocyte accumulation in patients with autoimmune thyroid disease (Graves' and Hashimoto's disease). Our study utilized euthyroid family members for one of our control groups (n = 48) thus significantly limiting familial, but not disease-specific, influences on these T cell phenotypes. Our principal new observations were found only in patients with Graves' disease. As previously reported, there was a decrease in CD8+ (suppressor/cytotoxic) T cells in the peripheral blood of patients with untreated hyperthyroid Graves' disease (n = 27) (mean +/- SEM, 19 +/- 1.1% in patients compared with 25 +/- 1.2% in controls, p = 0.03), a finding not observed in treated, euthyroid Graves' disease patients or their relatives. However, the relative number of CD8+ T cells, assessed by CD4:CD8 ratios, was increased in the intrathyroidal T cell populations (n = 10), when compared to normal and patient peripheral blood. There were no consistent changes in total CD4+ (helper) T cells in the peripheral blood of patients with treated and untreated Graves' disease but a reduction in CD4+2H4+ (suppressor-inducer) T cells was seen in patients undergoing surgery for Graves' disease (13 +/- 6.9% compared with 39 +/- 3.4%). Again, however, this T cell subset was increased within the target organ of the same patients (41 +/- 5.9%). These data point to either a selective accumulation, or a specific "homing", of certain T cell subsets within the thyroid gland of patients with Graves' disease where T cell differentiation may be strongly influenced by antithyroid drug treatment and the local immune environment.     

Budded Autographa californica NPV 64K protein: Further biochemical analysis and effects of postimmunoprecipitation sample preparation conditions

Previously it was shown that AcV1, a neutralizing monoclonal antibody of the Autographa californica nuclear polyhedrosis virus-budded phenotype reacted with a surface antigen present on infected cells during virus budding, and in the viral envelope (L. E. Volkman, P. A. Goldsmith, R. T. Hess, and P. Faulkner (1984), Virology 133, 354-362). Radioimmune precipitation of solubilized, [35S]methionine-labeled budded virus with AcV1 and analysis on SDS-PAGE revealed four bands consistently: one major band at 64,000 Da, and three minor bands at 127,000, 59,000, and 49,000 Da. The reason for the appearance of four bands instead of one was unclear. Data suggest that two of the bands, 49K and 59K, are aberrant, and are the products of sample preparation conditions. Further, evidence is presented that the 127K band is composed of dimers of the 64K protein, and that under nonreducing conditions, oligomers (trimers and tetramers) of 64K protein can also be detected. BVGP 64 is additionally shown to be phosphorylated and to have an isoelectric point of 3.15. The BVGP 64 epitope reactive with AcV1 is destroyed by interaction with SDS. This could account for the lack of neutralizing activity of antiserum made to the SDS-PAGE purified BVGP 64.     

Psychiatric features of individuals with problematic internet use

BACKGROUND: Problematic internet use has been described in the psychological literature as 'internet addiction' and 'pathological internet use'. However, there are no studies using face-to-face standardized psychiatric evaluations to identify behavioral characteristics, psychiatric comorbidity or family psychiatric history of individuals with this behavior. METHODS: Twenty individuals with problematic internet use were evaluated. Problematic internet use was defined as (1) uncontrollable, (2) markedly distressing, time-consuming or resulting in social, occupational or financial difficulties and (3) not solely present during hypomanic or manic symptoms. Evaluations included a semistructured interview about subjects' internet use, the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-IV (SCID-IV), family psychiatric history and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) modified for internet use. RESULTS: All (100%) subjects' problematic internet use met DSM-IV criteria for an impulse control disorder (ICD) not otherwise specified (NOS). All 20 subjects had at least one lifetime DSM-IV Axis I diagnosis in addition to their problematic internet use (mean+/-SD=5.1+/-3.5 diagnoses); 14 (70.0%) had a lifetime diagnosis of bipolar disorder (with 12 having bipolar I disorder). LIMITATIONS: Methodological limitations of this study included its small sample size, evaluation of psychiatric diagnoses by unblinded investigators, and lack of a control group. CONCLUSIONS: Problematic internet use may be associated with subjective distress, functional impairment and Axis I psychiatric disorders.     

Identification and localization of G protein subunits in human spermatozoa

Antibodies to alpha and beta subunits of guanine nucleotide regulatory proteins (G proteins) were used to identify which G proteins are present in mature human spermatozoa and to determine their subcellular localization. Immunoblots of membranes from spermatozoa demonstrate the presence of Galphai2, Galphai3, Galphaq/11 and Gbeta35 and the absence of Galphai1, Galpha0, Galphas, Galpha12, Galpha13, Galpha16, Galpha and Gbeta36. Indirect immunofluorescence demonstrates the presence of Galphaq/11 in the acrosome, with the highest proportion in the equatorial segment. Galphai2 is present in the acrosome, midpiece and tailpiece and Galphai3 in the postnuclear cap, midpiece and tailpiece. The Gbeta35 subunit is found mostly in the midpiece, with marginal labelling of the head, tailpiece and the equatorial segment of the acrosome. The distinct pattern of distribution of G proteins suggests that they may couple to receptors or effectors which also have discrete regions of localization in spermatozoa. These highly localized signal transduction pathways may regulate discrete functions, such as activation of the acrosome reaction, fusion with the oocyte and motility.