Cluster Analysis of the Klein Sexual Orientation Grid in Clinical and Nonclinical Samples: When Bisexuality Is Not Bisexuality

<div><p>A cluster analysis of the Klein Sexual Orientation Grid (KSOG) in three samples (Internet-recruited men and women; HIV study men) resulted in objectively determined 4- or 5-cluster classifications (such as “bi-heterosexual” or “bi-bisexual”). Group means and standard deviations on the KSOG's 21 items revealed that overtly erotic items (sexual fantasies, sexual behavior, sexual attraction) and self-identification items were more uniform within groups than social items (emotional preference, socialize with, lifestyle) were. The bisexual cluster in the HIV sample was distinctly different from all of the bisexual main sample clusters. Attempts to generalize from this clinical bisexual group to a larger population would be doomed to failure. This underscores the importance of recruiting nonclinical samples if one wants insight into the nature of bisexuality in the population at large. Our data empirically confirm many previous nonempirical warnings against clinical samples in studies of sexual orientation.</p></div

Independent, non-derived stereometric parameters of the optic nerve and nerve fiber layer in HIV+ patients compared to HIV-seronegative controls.

<p>HIV+ = subjects who are human immunodeficiency virus (HIV) positive, HIV- = subjects who are HIV negative controls, CD4 = CD4 cell count, SD = standard deviation, RNFL = retinal nerve fiber layer, mm–millimeter.</p><p>*—statistically significant</p><p>Independent, non-derived stereometric parameters of the optic nerve and nerve fiber layer in HIV+ patients compared to HIV-seronegative controls.</p

Baseline characteristics of the four groups.

<p>Baseline characteristics of the four groups.</p

Variability of HRT3 retinal nerve fiber layer cross sectional area by retinal regions among HIV+ and HIV-seronegative patients.

<p>HRT = Heidelberg retina tomography, HIV+ = subjects who are human immunodeficiency virus (HIV) positive, HIV- = subjects who are HIV negative controls, CD4 = CD4 cell count, SD = standard deviation, RNFL = retinal nerve fiber layer, Sup = superior, Inf = inferior.</p><p>*—statistically significant</p><p>Variability of HRT3 retinal nerve fiber layer cross sectional area by retinal regions among HIV+ and HIV-seronegative patients.</p

Epigenetic Alterations in the Brain Associated with HIV-1 Infection and Methamphetamine Dependence

<div><p>HIV involvement of the CNS continues to be a significant problem despite successful use of combination antiretroviral therapy (cART). Drugs of abuse can act in concert with HIV proteins to damage glia and neurons, worsening the neurotoxicity caused by HIV alone. Methamphetamine (METH) is a highly addictive psychostimulant drug, abuse of which has reached epidemic proportions and is associated with high-risk sexual behavior, increased HIV transmission, and development of drug resistance. HIV infection and METH dependence can have synergistic pathological effects, with preferential involvement of frontostriatal circuits. At the molecular level, epigenetic alterations have been reported for both HIV-1 infection and drug abuse, but the neuropathological pathways triggered by their combined effects are less known. We investigated epigenetic changes in the brain associated with HIV and METH. We analyzed postmortem frontal cortex tissue from 27 HIV seropositive individuals, 13 of which had a history of METH dependence, in comparison to 14 cases who never used METH. We detected changes in the expression of DNMT1, at mRNA and protein levels, that resulted in the increase of global DNA methylation. Genome-wide profiling of DNA methylation in a subset of cases, showed differential methylation on genes related to neurodegeneration; dopamine metabolism and transport; and oxidative phosphorylation. We provide evidence for the synergy of HIV and METH dependence on the patterns of DNA methylation on the host brain, which results in a distinctive landscape for the comorbid condition. Importantly, we identified new epigenetic targets that might aid in understanding the aggravated neurodegenerative, cognitive, motor and behavioral symptoms observed in persons living with HIV and addictions.</p></div

Combined HIV disease and METH dependence are associated with genome-wide DNA methylation changes in the frontal cortex.

<p><b><i>A</i></b><i>.</i> Schematic representation of the percentage of loci that showed gain or loss of methylation in the brain of HIV+ METH users as a fraction of total probes with differential methylation. <b><i>B</i></b><i>.</i> Distribution of average β values across samples showing enrichment in low-methylation (LMF, β values <20%) and high-methylation fractions (HMF, β values >80%). IMF, intermediate methylated fraction (β values <20% and >80%). <b><i>C</i></b><i>.</i> CpG neighborhood context analysis of loci showing differential methylation on the HIV+METH+ group. The graph represents the location of probes that showed increased methylation or decreased methylation on HIV+ METH user group (as percentage of total loci with differential methylation). CG Islands are defined as genomic regions of up to 200 bp showing enrichment of CpG dinucleotides. Shores are defined as regions up to 2 Kb from the CGi Start or End; Shelves are defined as the next 2 Kb boundaries from CGi shores. <b><i>D</i></b><i>.</i> Gene Ontology analysis of annotated genes showing differential methylation clustering by Biological Process.</p

Functional brain regions identified as showing risk-related differences between the HIV- and HIV+ groups while they performed the risky gains task.

<p>Functional brain regions identified as showing risk-related differences between the HIV- and HIV+ groups while they performed the risky gains task.</p

METH use results in increased global DNA methylation in the brains of HIV seropositive cases.

<p><b><i>A.</i></b> Global methylation was determined by ELISA quantification of 5-mC on genomic DNA from frontal cortex samples. Significant increase in DNA methylation was observed in HIV seropositive METH users. *p<0.05 by Wilcoxon matched pairs test. <b><i>B.</i></b> Cellular HIV-1 RNA levels correlate with DNA methylation levels as determined by Spearman correlation between global DNA methylation and log HIV-1 RNA in the brain R = 0.527 with p = 0.01. <b><i>C.</i></b> Quantitative real-time PCR showed significant increase in DNMT1 transcript levels on HIV seropositive individuals who used METH. <b><i>D.</i></b> METH exposure did not alter mRNA levels of DNMT3B, a closely related family member reported to have redundant functions to DNMT1 in the brain. *p<0.05 by Wilcoxon matched pairs test. <b><i>E.</i></b> Western blot analysis of DNMT1 protein content in the nucleus showing representative HIV+METH− and HIV+METH+ cases. <b><i>F.</i></b> Image analysis showing integrated pixel intensity of Dnmt1 immunoreactivity. <b><i>G.</i></b> Immunofluorescence detection of DNMT1 on frontal cortex sections. Green fluorescent signal correspond to DNMT1 immunoreactivity and blue signal corresponds to DAPI nuclear staining. <b><i>H.</i></b> Image analysis showing average DNMT1 positive nuclear counts. Bar represents 10 µm. One way ANOVA was used to determine statistical significance, *p<0.05.</p

Within the HIV+ group, graphs of the relationship between Kalichman Sexual Compulsivity Scaled Mean and a subset of the voxels in three of the clusters depicted in Figure 2 and Table 2.

<p>The subset of voxels is the overlap between the clusters showing between-group task related functional differences and those clusters identified by the robust regression analysis conducted only within the HIV+ group. The black line is the robust regression line on the difference between risky and safe responses. The red and blue lines are robust regression lines of the safe and risky components of the black line. L, left; R, right; Sup, Superior; Gy, Gyrus.</p

Characteristics of the HIV- and HIV+ groups.

<p>Characteristics of the HIV- and HIV+ groups.</p