Low uptake of HIV testing and no HIV positivity in stable serodiscordant heterosexual partners of long-term treated HIV-infected Thais

The objective of this study was to characterize HIV-serodiscordant heterosexual couples and to evaluate acceptance for HIV testing and HIV prevalence in nonindex partners. We conducted a cross-sectional study with quantitative and qualitative components. Two cohorts of 1767 HIV-positive people were screened to identify heterosexual HIV-serodiscordant couples. HIV-positive partners (index) were administered a questionnaire; CD4, viral load (VL), and antiretroviral therapy (ART) history were gathered from clinical records. HIV-negative/unknown status partners (nonindex) were invited for a similar questionnaire and HIV testing. In-depth interviews with three HIV-serodiscordant couples were conducted. Two hundred and ninety-seven index partners agreed to enroll in this study. The median duration of the relationship was 10 years, and 81% were sexually active. All but two index partners were on ART, and 98% had VL < 1000 copies/mL. Only 111 (37%) nonindex partners came for HIV testing, and all of them tested HIV-negative. In addition, only 41% of nonindex partners had HIV testing in the last one year. The main reasons for the nonindex partners not to come for HIV testing were “no interest” (n = 117, 63%) and “nondisclosure of HIV status” (n = 46, 25%). The latter was substantiated and explained by the qualitative outcome of this study, suggesting relation to stigma against HIV-positive people. Our results support the WHO recommendation for starting ART for treatment and prevention in HIV-serodiscordant couples at any CD4 count. Furthermore, we recommend the dissemination of data showing that no HIV transmission in heterosexual couples through sex practice has been observed provided VL is suppressed. This could be a powerful tool for effective fight against stigma and self-stigma in people living with HIV.     

Acrosomal Component of Rat Round Spermatids Recognized by a Novel Monoclonal Antibody

OBJECTIVE: To characterize immunocytochemically the antigen recognized which appears at specific stages of germ cell development and acrosomal biogenesis by the novel monoclonal antibody (Mab 3C2). METHODS: The novel monoclonal antibody (Mab 3C2) raised against testicular Sertoli and germ cells. RESULTS: The immunoreactivity of this Mab in testicular sections from immature 20-day-old rats was confined to the pachytene spermatocytes. In adult testis the Mab 3C2, besides meiotic cells, recognized also acrosomal component of round spermatids. The immune reaction was observed in Golgi and cap phases of acrosomal development until the stage VIII of the cycle of the seminiferous epithelium. Immunostaining was absent in acrosome of elongating and mature spermatids and indicated that some modifications in acrosomal protein may exist in subsequent stages of acrosomal development. CONCLUSIONS: Novel Mab 3C2 shares a common antigen in pachytene spermatocytes and round spermatids. Therefore, it may be a marker of meiotic and postmeiotic germ cells.     

Siderocalin-mediated recognition,sensitization, and cellular uptake of actinides

Synthetic radionuclides, such as the transuranic actinides plutonium, americium, and curium, present severe health threats as contaminants, and understanding the scope of the biochemical interactions involved in actinide transport is instrumental in managing human contamination. Here we show that siderocalin, a mammalian siderophore-binding protein from the lipocalin family, specifically binds lanthanide and actinide complexes through molecular recognition of the ligands chelating the metal ions. Using crystallography, we structurally characterized the resulting siderocalin–transuranic actinide complexes, providing unprecedented insights into the biological coordination of heavy radioelements. In controlled in vitro assays, we found that intracellular plutonium uptake can occur through siderocalin-mediated endocytosis. We also demonstrated that siderocalin can act as a synergistic antenna to sensitize the luminescence of trivalent lanthanide and actinide ions in ternary protein–ligand complexes, dramatically increasing the brightness and efficiency of intramolecular energy transfer processes that give rise to metal luminescence. Our results identify siderocalin as a potential player in the biological trafficking of f elements, but through a secondary ligand-based metal sequestration mechanism. Beyond elucidating contamination pathways, this work is a starting point for the design of two-stage biomimetic platforms for photoluminescence, separation, and transport applications.Events of the last decade have heightened public concern that radionuclides may be released to the environment either deliberately or accidentally (1, 2), with such events potentially leading to the internal contamination of a large number of individuals. The actinides are all highly radioactive, as are some lanthanide fission products, and many of their isotopes decay by alpha particle emission (3). Once internalized, they are distributed to various tissues with patterns that depend on the chemical and physical form of the contaminant in question (4). The densely ionizing alpha particles emitted by actinides when retained can cause tissue damage and induce cancer in target tissues in a dose-dependent manner (5). Sufficiently high radionuclide doses may also cause manifestations of acute radiation syndrome. The tissue distribution of an actinide will therefore determine the pattern of injury observed and its radiological and chemical toxicities may lead to serious adverse health effects (6–8). Although they are known to rapidly circulate and deposit into major organs such as bone, liver, or kidney after contamination (6, 8–10), the specific molecular mechanisms associated with mammalian uptake of these toxic heavy elements remain largely unexplored. Proposed mammalian actinide acquisition and transport mechanisms have typically focused on proteins that use conserved motifs to directly bind the essential elements iron or calcium (6, 8, 10–13), such as transferrin (14–18), ferritin (13), osteopontin (19), or fetuin (20). Siderocalin (Scn), an essential antibacterial protein that sequesters iron (21, 22), and an important component of iron trafficking (23), is distinct in that it binds ferric iron indirectly, through tight complexes with a siderophore or siderophore-derived chelator. For example, Scn binds the archetypical hexadentate siderophore Enterobactin (Ent; Fig. 1A) as a ferric complex ([Fe^III(Ent)]^3-) with a subnanomolar equilibrium dissociation constant (K_d = 0.4 nM) (22). The binding of [Fe^III(Ent)]^3- by Scn is mainly driven by electrostatic and cation-π interactions with the three Ent catecholamide moieties (22) (Fig. 1B), rather than the metal directly, allowing other metals to be substituted (24) (e.g., Al, Ga, V, and In), with some metal–Ent complexes showing even tighter binding than [Fe^III(Ent)]^3-. We hypothesized that the metal ion could be further substituted without affecting recognition significantly, potentially uncovering endogenous trafficking pathways for other elements or enabling novel applications. We therefore investigated the affinity of Scn for lanthanide and actinide complexes of Ent and of the synthetic octadentate hydroxypyridinonate siderophore analog, 3,4,3-LI(1,2-HOPO) (“HOPO”; Fig. 1A), reported to form some of the most stable, fully coordinated f-element complexes (25, 26). Further X-ray diffraction and spectroscopic characterization of the resulting Scn adducts formed with chelated f elements provided crystal structures of protein complexes with four actinide elements (Th, Pu, Am, and Cm), and revealed the protein as an antenna that sensitizes metal luminescence through highly efficient intramolecular energy transfer processes. Finally, the potential role of Scn in actinide transport was examined through a series of in vitro experiments probing the cellular uptake of plutonium. The two-stage protein–ligand-based metal sequestration mechanism described here therefore paves the way to new avenues not only in exploring the biological chemistry of actinide contamination but also in designing future separation and photoluminescence tools.Open in a separate windowFig. 1.Determination of Scn affinity for Ent and 3,4,3-LI(1,2-HOPO) complexes of selected lanthanide and actinide elements. (A) Molecular structures of the hexadentate Ent (Upper) and octadentate 3,4,3-LI(1,2-HOPO) (HOPO; Lower) ligands; metal-binding atoms are shown in red. (B) A view into the Scn calyx, showing the interaction between key residue side chains and [Fe^III(Ent)]^3-. Scn is shown as a semitransparent molecular surface, colored by electrostatic potential (blue = positive, red = negative). Side chains are labeled and shown in a licorice-stick representation, colored by atom type (carbon: gray, nitrogen: blue, and oxygen: red). A direct contact between Y106 and the iron atom (red sphere) is indicated with a dotted line. The snugness of the K125/K134 “key” pocket is apparent, as is the steric occlusion of adducts to the 3, 4, and 5 positions of the catechol bound there. The deepest calyx pocket is at the upper right.     

Hepatocyte growth factor induces retinal vascular permeability via MAP-kinase and PI-3 kinase without altering retinal hemodynamics

PURPOSE: Although vascular endothelial growth factor (VEGF) is a key mediator of retinal vascular permeability (RVP), there may be additional humoral contributors. Hepatocyte growth factor (HGF) induces endothelial cell separation, regulates expression of cell adhesion molecules and is increased in the vitreous fluid of patients with proliferative diabetic retinopathy. The purpose of this study was to evaluate the in vivo effects of HGF on RVP and retinal hemodynamics and delineate the signaling pathways. METHODS: RVP was assessed by vitreous fluorescein fluorophotometry in rats. Time course and dose-response were determined after intravitreal HGF injection. MAP kinase (MAPK), phosphatidylinositol 3-kinase (PI-3 kinase), and protein kinase C (PKC) involvement were examined by using selective inhibitors. Retinal blood flow (RBF) and mean circulation time (MCT) were evaluated by video fluorescein angiography. RESULTS: HGF increased RVP in a time- and dose-dependent manner. HGF-induced RVP was evident 5 minutes after injection, and reached maximal levels after 25 minutes (+107% versus vehicle, P=0.002). This effect was comparable to that of maximum VEGF stimulation (134%+/-128% at 25 ng/mL). Selective inhibitors of MAPK (PD98059) and PI-3 kinase (LY294002) suppressed HGF-induced RVP by 86%+/-44% (P=0.015) and 97%+/-59% (P=0.021), respectively. Non-isoform-selective inhibition of PKC did not significantly decrease HGF-induced RVP. Although VEGF increases RBF and reduces MCT, HGF did not affect either. CONCLUSIONS: HGF increases RVP in a time- and dose-dependent manner at physiologically relevant concentrations with a magnitude and profile similar to that of VEGF, without affecting retinal hemodynamics. Thus, HGF may represent another clinically significant contributor to retinal edema distinct from the actions of VEGF.     

Maternal reflective functioning, attachment, and the transmission gap: a preliminary study

The notion that maternal reflective functioning, namely the mother's capacity to hold her baby and his mental states in mind, plays a vital role in the intergenerational transmission of attachment is investigated (Fonagy, Gergely, Jurist, & Target, 2002; Fonagy et al., 1995; Slade, this volume). A parent's capacity to understand the nature and function of her own as well as her child's mental states, thus allowing her to create both a physical and psychological experience of comfort and safety for her child, is proposed. In this study of 40 mothers and their babies, maternal reflective functioning is measured using the Parent Development Interview (PDI; Aber, Slade, Berger, Bresgi, & Kaplan, 1985), and scored for reflective functioning using an addendum to Fonagy, Target, Steele, & Steele's (1998) reflective functioning scoring manual (Slade, Bernbach, Grienenberger, Levy, & Locker, 2004). The relations between maternal reflective functioning and both adult (measured in pregnancy) and infant attachment (measured at 14 months) are examined. The findings indicate that relations between adult attachment and parental reflective functioning are significant, as are relations between parental reflective functioning and infant attachment. A preliminary mediation analysis suggests that parental reflective functioning plays a crucial role in the intergenerational transmission of attachment.     

Incremental value of diffusion weighted and dynamic contrast enhanced MRI in the detection of locally recurrent prostate cancer after radiation treatment: preliminary results

Objectives  

To assess the incremental value of diffusion-weighted (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) to T2-weighted MRI (T2WI) in detecting locally recurrent prostate cancer after radiotherapy.     

Varenicline for smoking cessation: A placebo-controlled, randomized study

Background and objective:   Varenicline tartrate, a novel, selective, nicotinic acetylcholine receptor partial agonist, has been developed specifically as a smoking cessation drug. This study evaluated the efficacy of a standard regimen of varenicline compared with placebo for smoking cessation in 333 subjects in China, Singapore and Thailand.
Methods:   This 24-week, randomized, double-blind, placebo-controlled trial of varenicline, 1 mg bd, consisted of a 12-week treatment period followed by a 12-week non-treatment follow-up period. The primary study end-point was the 4-week continuous abstinence rate defined as the proportion of subjects who reported total abstinence from smoking and other nicotine products from weeks 9–12. A key secondary end-point was the continuous abstinence rate from weeks 9–24, defined as the proportion of subjects who achieved the primary end-point as well as total abstinence from all tobacco products from weeks 13–24.
Results:   Both end-points were achieved by a significantly higher proportion of subjects in the varenicline group than in the placebo group. The 4-week continuous abstinence end-point was achieved by 50.3% and 31.6% in the varenicline and placebo groups, respectively ( P  = 0.0003), while continuous abstinence from weeks 9–24 was achieved by 38.2% and 25.0% of subjects, respectively ( P  = 0.0080). The treatment effect was generalizable by treatment centre and country. Varenicline was safe and appeared to be well tolerated by most subjects.
Conclusion:   Varenicline was significantly more efficacious for smoking cessation than placebo over a 12-week treatment period and a further 12-week non-treatment follow-up period in smokers from China, Singapore and Thailand. No significant side-effects were noted.     

Serum profiles of free and conjugated neuroactive pregnanolone isomers in nonpregnant women of fertile age

BACKGROUND: Pregnanolone isomers (PI) with a hydroxy group in the 3alpha-position are neuroinhibitors operating via positive modulation of GABA(A) receptors. The 3beta-PI and sulfates of PI and pregnenolone exert the opposite effect. In addition to the brain's in situ synthesis, some circulating steroids can penetrate the blood-brain barrier. METHODS: To assess the physiological impact of peripheral endogenous neuroactive pregnanolone isomers and their polar conjugates in women, serum allopregnanolone (P3alpha5alpha), isopregnanolone (P3beta5alpha), pregnanolone (P3alpha5beta), epipregnanolone (P3beta5beta), pregnenolone, estradiol (including their polar conjugates), and additional steroids were measured in 16 women in the follicular and luteal phases of the menstrual cycle using gas chromatography/mass spectrometry and RIA for the analysis. Linear models and Spearman's correlations were used for data evaluation. RESULTS AND DISCUSSION: The levels of conjugated PI were from one to almost three orders of magnitude higher in comparison with the free steroids. The results indicate that a substantial proportion of the progesterone is metabolized in the sequence progesterone-->5beta-dihydroprogesterone-->P3alpha5beta-->conjugated P3alpha5beta. The sulfation of PI and particularly of P3alpha5beta moderates the levels of free PI and restrains estradiol biosynthesis via progesterone degradation. PI including the conjugates reflected changing progesterone formation during the menstrual cycle. In the follicular phase, the positive correlation with conjugated pregnenolone, the independence of progesterone, and the negative age relationships of PI indicate their adrenal origin. The dependence on progesterone and the independence of conjugated pregnenolone suggest a gonadal source of PI in the luteal phase. The neuroactivating PI prevailed over neuroinhibiting PI.     

Endovascular repair of traumatic thoracic aortic disruption

In a patient with multiple trauma, blunt thoracic trauma with concomitant aortic disruption is often eminently lethal, ranking second to head injury as the most common cause of trauma-related deaths. Open surgical repair of the aortic lesion has morbidity and mortality rates that are among the highest in the field of cardiovascular surgery. Results with thoracic endovascular aortic repair for traumatic aortic disruption are promising. The facility requirements, technique, and early results of thoracic endovascular aortic repair for the treatment of this difficult aortic injury are presented.