379 research outputs found

    Social Context, Sexual Strategies, and Risks for HIV Transmission among Men who have Sex with Men: The South Beach Health Survey

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    In a population-based sample of 193 men who had sex with men in South Beach, Miami-Dade County, Florida, two indicators of social context—choice of sexual relationships and perceived HIV-infection status—were used to analyze residents who engaged in certain sexual practices with their partners. The vast majority (88.6%) of respondents reported engagement in anal sex during the previous 12 months; 20.2% reported unprotected anal intercourse (UAI) with ejaculation with any partner and 12.4% reported UAI with ejaculation with one or more casual partners. Findings supported the hypothesis that primary partner relationships and perceived HIV status are important variables for understanding engagement in UAI with ejaculation. Men who engaged in such behaviors with casual partners were more likely to have negative attitudes towards condoms, report difficulty communicating desires for safer sex, disagree with the belief that AIDS is fatal, and be intoxicated during anal intercourse. Men who reported engaging in anal intercourse, but who never shared unprotected ejaculations, were most likely to be unknowingly infected with HIV, suggesting that many men may become infected while following what they believe to be “safer sex practices.” In designing effective interventions, public health authorities need to take into account socially embedded risk-negotiating practices

    Limitations of Counseling and Testing in CDC\u27s HIV Prevention Efforts

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    To the Editor: We were delighted to see that our colleagues at the Centers for Disease Control and Prevention (CDC) had read our article (Darrow et al., 1998a) and responded (Wolitski and Doll, 1999). Their criticisms of our cross-sectional study of 51 HIV-infected men who have sex with men (MSM) and live in South Beach are welcomed and appreciated. In this brief reply, we continue the dialogue by addressing their concerns and recommending an appropriate course of action

    Impact of HIV Counseling and Testing on HIV-Infected Men who have Sex with Men: The South Beach Health Survey

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    The impact of HIV counseling and testing on sexual risk-taking and related behaviors reported by HIV-infected men who have sex with men (MSM) was examined in a cross-sectional study conducted among a representative sample of residents living in a resort area. Participants provided specimens of oral mucosal transudate for HIV-antibody testing, were interviewed in their homes, and completed a self-administered questionnaire. Specimens were tested by modified ELISA and, if repeatedly positive, confirmed by Western blot. Of 205 men enrolled, 51 (24.9%) tested positive for antibody to HIV. All 51 had been counseled and tested for antibody to HIV-1 (median = 4 tests); 37 (74%) of 50 reported that their most recent test was positive. Twenty (39.2%) said they had engaged in unprotected insertive anal intercourse in the past year; 15 (29.4%) engaged in unprotected insertive anal intercourse with partners who may have been susceptible to HIV infection. Men who reported that their last HIV-antibody test was positive were three times more likely to have engaged in unprotected insertive anal intercourse in the past year (45.9%) as those who did not know they were infected with HIV (15.4%). Counseling and testing is ineffective as a measure for promoting behavior change among HIV-positive MSM in South Beach. More effective social and behavioral interventions must be developed, implemented, and evaluated

    Assessment of viral and non-viral gene transfer into adult rat brains using HSV-1, calcium phosphate and PEI-based methods

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    CNS gene transfer could provide new approaches to the modelling of neurodegenerative diseases and devising potential therapies. One such disorder is Parkinson’s disease (PD), in which dysfunction of several different metabolic processes has been implicated. Here we review the literature on gene transfer systems based on herpes simplex virus type 1 (HSV-1) and non-viral polyethyleneimine (PEI) and calcium phosphate nanoparticle methods. We also assess the usefulness of various CNS gene delivery methods and present some of our own data to exemplify such usefulness. Our data result from vectors stereotaxically introduced to the substantia nigra (SN) of adult rats and evaluated 1 week and/or 1 month post injection using histochemical methods to assess recombinant ß-galactosidase enzyme activity. Gene transfer using PEI or calcium phosphate-mediated transfections was observed for both methods and PEI was comparable to that of HSV-1 amplicon. Our data show that the amplicon delivery was markedly increased when packaged with a helper virus and was similar to the expression profile achieved with a full-size replication-defective HSV-1 recombinant (8117/43). We also examine whether PEI or HSV-1 amplicon-mediated gene transfer could facilitate assessment of the biological effects induced by a dominant negative FGF receptor-1 mutant to model the reduced FGF signalling thought to occur in Parkinson’s disease

    Macrosystems ecology: Understanding ecological patterns and processes at continental scales

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    Macrosystems ecology is the study of diverse ecological phenomena at the scale of regions to continents and their interactions with phenomena at other scales. This emerging subdiscipline addresses ecological questions and environmental problems at these broad scales. Here, we describe this new field, show how it relates to modern ecological study, and highlight opportunities that stem from taking a macrosystems perspective. We present a hierarchical framework for investigating macrosystems at any level of ecological organization and in relation to broader and finer scales. Building on well-established theory and concepts from other subdisciplines of ecology, we identify feedbacks, linkages among distant regions, and interactions that cross scales of space and time as the most likely sources of unexpected and novel behaviors in macrosystems. We present three examples that highlight the importance of this multiscaled systems perspective for understanding the ecology of regions to continents

    Electrocatalysis at Organic–Metal Interfaces: Identification of Structure–Reactivity Relationships for CO_2 Reduction at Modified Cu Surfaces

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    The limited selectivity of existing CO_2 reduction catalysts and rising levels of CO_2 in the atmosphere necessitate the identification of specific structure–reactivity relationships to inform catalyst development. Herein, we develop a predictive framework to tune the selectivity of CO_2 reduction on Cu by examining a series of polymeric and molecular modifiers. We find that protic species enhance selectivity for H_2, hydrophilic species enhance formic acid formation, and cationic hydrophobic species enhance CO selectivity. ReaxFF reactive molecular dynamics simulations indicate that the hydrophilic/hydrophobic modifiers influence the formation of surface hydrides, which yield formic acid or H_2. These observations offer insights into how these modifiers influence catalytic behavior at the non-precious Cu surface and may aid in the future implementation of organic structures in CO_2 reduction devices

    Severe paraneoplastic hypoglycemia in a patient with a gastrointestinal stromal tumor with an exon 9 mutation: a case report

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    BACKGROUND: Non-islet cell tumor induced hypoglycemia (NICTH) is a very rare phenomenon, but even more so in gastrointestinal stromal tumors. It tends to present in large or metastatic tumors, and can appear at any time in the progression of the disease. We present herein a case of NICTH in a GIST tumor and report an exon 9 mutation associated to it. CASE PRESENTATION: A thirty nine year-old man with a recurrent, metastatic gastrointestinal stromal tumor presented to the hospital with nausea, dizziness, loss of consciousness, and profound hypoglycemia (20 mg/dL). There was no evidence of factitious hypoglycemia. He was stabilized with a continuous glucose infusion and following selective vascular embolization, the patient underwent debulking of a multicentric 40 cm × 25 cm × 10 cm gastrointestinal stromal tumor. After resection, the patient became euglycemic and returned to his normal activities. Tumor analysis confirmed excessive production of insulin-like growth factor II m-RNA and the precursor protein, "big" insulin-like growth factor II. Mutational analysis also identified a rare, 6 bp tandem repeat insert (gcctat) at position 1530 in exon 9 of KIT. CONCLUSION: Optimal management of gastrointestinal stromal tumor-induced hypoglycemia requires a multidisciplinary approach, and surgical debulking is the treatment of choice to obtain immediate symptom relief. Imatinib or combinations of glucocorticoids and growth hormone are alternative palliative strategies for symptomatic hypoglycemia. In addition, mutations in exon 9 of the tyrosine kinase receptor KIT occur in 11–20% of GIST and are often associated with poor patient outcomes. The association of this KIT mutation with non-islet cell tumor induced hypoglycemia has yet to be established

    A deletion in GDF7 is associated with a heritable forebrain commissural malformation concurrent with ventriculomegaly and interhemispheric cysts in cats

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    Publisher Copyright: © 2020 by the authors.An inherited neurologic syndrome in a family of mixed-breed Oriental cats has been characterized as forebrain commissural malformation, concurrent with ventriculomegaly and interhemispheric cysts. However, the genetic basis for this autosomal recessive syndrome in cats is unknown. Forty-three cats were genotyped on the Illumina Infinium Feline 63K iSelect DNA Array and used for analyses. Genome-wide association studies, including a sib-transmission disequilibrium test and a case-control association analysis, and homozygosity mapping, identified a critical region on cat chromosome A3. Short-read whole genome sequencing was completed for a cat trio segregating with the syndrome. A homozygous 7 bp deletion in growth differentiation factor 7 (GDF7) (c.221_227delGCCGCGC [p.Arg74Profs]) was identified in affected cats, by comparison to the 99 Lives Cat variant dataset, validated using Sanger sequencing and genotyped by fragment analyses. This variant was not identified in 192 unaffected cats in the 99 Lives dataset. The variant segregated concordantly in an extended pedigree. In mice, GDF7 mRNA is expressed within the roof plate when commissural axons initiate ventrally-directed growth. This finding emphasized the importance of GDF7 in the neurodevelopmental process in the mammalian brain. A genetic test can be developed for use by cat breeders to eradicate this variant.Peer reviewe

    Werewolf, there wolf : Variants in hairless associated with hypotrichia and roaning in the lykoi cat breed

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    Publisher Copyright: © 2020 by the authors. Licensee MDPI, Basel, Switzerland.A variety of cat breeds have been developed via novelty selection on aesthetic, dermatological traits, such as coat colors and fur types. A recently developed breed, the lykoi (a.k.a. werewolf cat), was bred from cats with a sparse hair coat with roaning, implying full color and all white hairs. The lykoi phenotype is a form of hypotrichia, presenting as a significant reduction in the average numbers of follicles per hair follicle group as compared to domestic shorthair cats, a mild to severe perifollicular to mural lymphocytic infiltration in 77% of observed hair follicle groups, and the follicles are often miniaturized, dilated, and dysplastic. Whole genome sequencing was conducted on a single lykoi cat that was a cross between two independently ascertained lineages. Comparison to the 99 Lives dataset of 194 non‐lykoi cats suggested two variants in the cat homolog for Hairless (HR) (HR lysine demethylase and nuclear receptor corepressor) as candidate causal gene variants. The lykoi cat was a compound heterozygote for two loss of function variants in HR, an exon 3 c.1255_1256dupGT (chrB1:36040783), which should produce a stop codon at amino acid 420 (p.Gln420Serfs*100) and, an exon 18 c.3389insGACA (chrB1:36051555), which should produce a stop codon at amino acid position 1130 (p.Ser1130Argfs*29). Ascertainment of 14 additional cats from founder lineages from Canada, France and different areas of the USA identified four additional loss of function HR variants likely causing the highly similar phenotypic hair coat across the diverse cats. The novel variants in HR for cat hypotrichia can now be established between minor differences in the phenotypic presentations.Peer reviewe
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