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Biomedical subjects

M Koss

Publications and source records attributed to M Koss.

At least 19 recordsLinked to original sources

Factors associated with HIV sero-positivity in young, rural South African men.

OBJECTIVE: To describe factors associated with HIV infection in men aged 15-26 years. SETTING: Rural Eastern Cape Province, South Africa. SAMPLE: A total of 1277 sexually experienced Xhosa male volunteers from 70 villages participating in a cluster randomized controlled trial of an HIV behavioural intervention. Xhosas circumcise during manhood initiation rituals. DESIGN: Cross-sectional, analysis of the study's baseline interviews. MAIN MEASURE: HIV sero-status, sexual practices measured with an interviewer-administered questionnaire. RESULTS: About 2% of the men were HIV positive. A logistic regression model showed HIV positivity to be associated with age (OR 1.55; 95%CI 1.22-1.95), having made a woman pregnant (OR 2.93; 95% CI 1.28-6.68), having been circumcised (OR 0.40; 95% CI 0.16-0.98), and having had sex with a man (OR 3.61; 95% CI 1.0-13.0). CONCLUSIONS: Our findings provide further evidence to suggest that circumcision is protective. There was much heterosexual risk taking among men but only pregnancy (with its association with sexual frequency) predicted HIV sero-positivity. Although relatively rare, same-sex sexual experiences were a risk factor. Male-male sexual contact is rarely assessed in HIV research in Africa and almost never addressed in general HIV prevention programming. Our findings suggest that it should be given more attention.

Adolescent↗

Factors associated with HIV sero-status in young rural South African women: connections between intimate partner violence and HIV.

BACKGROUND: This paper aims to describe factors associated with HIV sero-status in young, rural South African women and the relationship between intimate partner violence (IPV) and HIV. METHODS: A total of 1295 sexually active female volunteers, aged 15-26, from 70 villages were recruited to participate in a cluster randomized controlled trial of an HIV behavioural intervention. The main measures were HIV sero-status, and IPV and sexual practices measured using a questionnaire administered during baseline interviews. RESULTS: About 12.4% of women had HIV and 26.6% had experienced more than one episode of physical or sexual IPV. After adjusting for age, HIV infection was associated with having three or more past year partners [odds ratio (OR) 2.39; 95% confidence interval (95% CI) 1.48-3.85], sex in past 3 months (OR 3.33; 95% CI 1.87-5.94), a partner three or more years older (OR 1.69; 95% CI 1.16-2.48), and a more educated partner (OR 1.91; 95% CI 1.30-2.78). IPV was associated with HIV in two-way analyses (OR 1.56; 95% CI 1.08-2.23), but the effect was non-significant after adjusting for HIV risk behaviours. The experience of IPV was strongly associated with past year partner numbers, time of last sex, and partner's education; it was also marginally associated with partner age difference. Adverse experiences in childhood, including sexual abuse, increased the likelihood of having more past year partners (OR 1.43; 95% CI 1.21-1.69). CONCLUSIONS: IPV was strongly associated with most of the identified HIV risk factors. Our findings provide further evidence of links between IPV and HIV among women and the importance of joint prevention.

Adolescent↗

A cluster randomized-controlled trial to determine the effectiveness of Stepping Stones in preventing HIV infections and promoting safer sexual behaviour amongst youth in the rural Eastern Cape, South Africa: trial design, methods and baseline findings.

OBJECTIVE: To describe the study design, methods and baseline findings of a behavioural intervention trial aimed at reducing HIV incidence. METHOD: A cluster randomized-controlled trial (RCT) conducted in 70 villages in rural South Africa. A behavioural intervention, Stepping Stones, was implemented in 35 communities in two workshops of 20 men and 20 women in each community who met for 17 sessions (50 h) over a period of 3-12 weeks. Individuals in the control arm communities attended a single session of about 3 h on HIV and safer sex. Impact assessment was conducted through two questionnaire and serological surveys at 12-month intervals. The primary outcome was HIV incidence and secondary measures included changes in knowledge, attitude and sexual behaviours. Qualitative research was also undertaken with 10 men and 10 women from two sites receiving the intervention (one rural and one urban) and five men and five women from one village in the control arm. They were interviewed individually three times prior to the workshops and then 9-12 months later. RESULTS: A total of 2776 participants (1409 intervention and 1367 control) were enrolled at baseline and had an interview, and HIV sero-status was established. HIV baseline prevalence rates in women were 9.8% in the intervention arm and 12.8% in the control arm. In men the prevalence was 1.7% in the intervention arm and 2.1% in the control arm. Demographic and behavioural characteristics were similar in the two arms. In the intervention groups 59.9% of participants attended more than 75% of the sessions. In the control group 66.3% attended the control session. CONCLUSION: This is the third RCT to be conducted in sub-Saharan Africa evaluating a behavioural intervention using HIV incidence as a primary outcome. It is of particular interest as the intervention in question is used in many developing countries. There is good baseline comparability between the study arms and the process data on the workshops suggested that the interventions were feasible and adequately implemented.

Adolescent↗

Role of bovine chemokines produced by dendritic cells in respiratory syncytial virus-induced T cell proliferation.

Respiratory syncytial virus (RSV) has been reported to induce the production of chemokines in the airway epithelia. Dendritic cells (DC) are the most potent antigen-presenting cells. They are located throughout the body and release chemokines in response to inflammation and infection. We have investigated the chemokine profile of bovine DC in response to exposure to bovine RSV (BRSV). Transcripts for several chemokines were detected by RT-PCR, subsequently cloned and expressed, and the products analysed by western blotting. To test the effect of the recombinant chemokines on RSV-induced T cell proliferation, DC were pulsed with BRSV, irradiated, and added to purified bovine CD4(+) T cells from RSV-immune cattle in combination with various concentrations of recombinant chemokines, and the proliferative response of the T cells assessed. Eotaxin was the only chemokine, of those investigated, that specifically enhanced the T cell response to BRSV-pulsed DC. Addition of MIP-1alpha to control wells or to wells containing BRSV-pulsed DC had similar effects, suggesting non-specific stimulation of T cells. RANTES and MIP-3alpha did not seem to influence the proliferative response of T cells co-cultured with BRSV-pulsed DC. Thus, although BRSV induced the production of several chemokines by DC, only eotaxin promoted a BRSV specific CD4(+) T cell proliferative response.

Animals↗

Imagery rehearsal therapy for chronic nightmares in sexual assault survivors with posttraumatic stress disorder: a randomized controlled trial.

CONTEXT: Chronic nightmares occur frequently in patients with posttraumatic stress disorder (PTSD) but are not usually a primary target of treatment. OBJECTIVE: To determine if treating chronic nightmares with imagery rehearsal therapy (IRT) reduces the frequency of disturbing dreams, improves sleep quality, and decreases PTSD symptom severity. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial conducted from 1995 to 1999 among 168 women in New Mexico; 95% had moderate-to-severe PTSD, 97% had experienced rape or other sexual assault, 77% reported life-threatening sexual assault, and 58% reported repeated exposure to sexual abuse in childhood or adolescence. INTERVENTION: Participants were randomized to receive treatment (n = 88) or to the wait-list control group (n = 80). The treatment group received IRT in 3 sessions; controls received no additional intervention, but continued any ongoing treatment. MAIN OUTCOME MEASURES: Scores on the Nightmare Frequency Questionnaire (NFQ), Pittsburgh Sleep Quality Index (PSQI), PTSD Symptom Scale (PSS), and Clinician-Administered PTSD Scale (CAPS) at 3- and 6-month follow-up. RESULTS: A total of 114 participants completed follow-up at 3 and/or 6 months. Comparing baseline to follow-up (n = 97-114), treatment significantly reduced nights per week with nightmares (Cohen d = 1.24; P<.001) and number of nightmares per week (Cohen d = 0.85; P<.001) on the NFQ and improved sleep (on the PSQI, Cohen d = 0.67; P<.001) and PTSD symptoms (on the PSS, Cohen d = 1.00; P<.001 and on the CAPS, Cohen d = 1.53; P<.001). Control participants showed small, nonsignificant improvements for the same measures (mean Cohen d = 0.21). In a 3-point analysis (n = 66-77), improvements occurred in the treatment group at 3-month follow-up (treatment vs control group, Cohen d = 1.15 vs 0.07 for nights per week with nightmares; 0.95 vs -0.06 for nightmares per week; 0.77 vs 0.31 on the PSQI, and 1.06 vs 0.31 on the PSS) and were sustained without further intervention or contact between 3 and 6 months. An intent-to-treat analysis (n = 168) confirmed significant differences between treatment and control groups for nightmares, sleep, and PTSD (all P<.02) with moderate effect sizes for treatment (mean Cohen d = 0.60) and small effect sizes for controls (mean Cohen d = 0.14). Posttraumatic stress symptoms decreased by at least 1 level of clinical severity in 65% of the treatment group compared with symptoms worsening or not changing in 69% of controls (chi(2)(1) = 12.80; P<.001). CONCLUSIONS: Imagery rehearsal therapy is a brief, well-tolerated treatment that appears to decrease chronic nightmares, improve sleep quality, and decrease PTSD symptom severity.

Adult↗

Complex insomnia: insomnia and sleep-disordered breathing in a consecutive series of crime victims with nightmares and PTSD.

BACKGROUND: Sleep disturbance in posttraumatic stress disorder is very common. However, no previous posttraumatic stress disorder studies systematically examined sleep breathing disturbances, which might influence nightmares, insomnia, and posttraumatic stress disorder symptoms. METHODS: Forty-four consecutive crime victims with nightmares and insomnia underwent standard polysomnography coupled with a nasal pressure transducer to measure airflow limitation diagnostic of obstructive sleep apnea and upper airway resistance syndrome. RESULTS: Forty of 44 participants tested positive on objective sleep studies based on conservative respiratory disturbance indices of more than 15 events per hour; 22 patients suffered from obstructive sleep apnea and 18 suffered from upper airway resistance syndrome. CONCLUSIONS: In an uncontrolled study, insomnia and sleep-disordered breathing were extremely prevalent in this small and select sample of crime victims. Research is needed to study 1) prevalence of sleep-disordered breathing in other posttraumatic stress disorder populations using appropriate controls and nasal pressure transducers and 2) effects of sleep treatment on posttraumatic stress symptoms in trauma survivors with comorbid obstructive sleep apnea or upper airway resistance syndrome. In the interim, some posttraumatic stress disorder patients may benefit from sleep medicine evaluations.

Adult↗

The relationship of sleep quality and posttraumatic stress to potential sleep disorders in sexual assault survivors with nightmares, insomnia, and PTSD.

Sleep quality and posttraumatic stress disorder (PTSD) were examined in 151 sexual assault survivors, 77% of whom had previously reported symptoms of sleep-disordered breathing (SDB) or sleep movement disorders (SMD) or both. Participants completed the Pittsburgh Sleep Quality Index (PSQI) and the Posttraumatic Stress Scale (PSS). High PSQI scores reflected extremely poor sleep quality and correlated with PSS scores. PSQI scores were greater in participants with potential SDB or SMD or both. PSQI or PSS scores coupled with body-mass index and use of antidepressants or anxiolytics predicted potential sleep disorders. The relationship between sleep and posttraumatic stress appears to be more complex than can be explained by the current PTSD paradigm; and, sleep breathing and sleep movement disorders may be associated with this complexity.

Adult↗

Mitotic counting in surgical pathology: sampling bias, heterogeneity and statistical uncertainty.

Mitotic counting in surgical pathology: sampling bias, heterogeneity and statistical uncertainty Although several articles on the methodological aspects of mitotic counting have been published, the effects of macroscopic sampling and tumour heterogeneity have not been discussed in any detail. In this review the essential elements for a standardized mitotic counting protocol are described, including microscopic calibration, specific morphological criteria, macroscopic selection, counting procedure, effect of biological variation, threshold, and the setting of an area of uncertainty ('grey area'). We propose that the use of a standard area for mitotic quantification and of a grey area in mitotic counting protocols will facilitate the application of mitotic counting in diagnostic and prognostic pathology.

Data Interpretation, Statistical↗

Idiopathic pulmonary fibrosis and malignancy.

The reported frequency of lung cancer in the setting of diffuse pulmonary fibrosis varies greatly, depending on the country of origin and the type of study. Most recent reports regarding diffuse pulmonary fibrosis in general and idiopathic pulmonary fibrosis in particular and lung cancers come from Japan; only a few clinical studies of this issue are available from other countries of the world, including the United States. The reported frequency ranges from 4.8% in the United States to 48.2% in Japan. The most frequent type of cancer is adenocarcinoma. Risk factors may include cigarette smoking, exposure to metal dusts, onset of idiopathic pulmonary fibrosis at an older age, and male predominance. Possible pathologic mechanisms are summarized. Given the very poor prognosis of idiopathic pulmonary fibrosis itself, with a mean survival of only 2.8 years, and that different diagnostic criteria were used in each study, it is likely that many of these studies are flawed because they evaluate lesions other than idiopathic pulmonary fibrosis. Thus, the frequency of lung cancer in idiopathic pulmonary fibrosis is still uncertain, and clearly requires follow-up of cohorts of clinically well-characterized patients, using standard diagnostic criteria for idiopathic pulmonary fibrosis. Finally, if the association between idiopathic pulmonary fibrosis and lung cancer is reconfirmed in these studies, the molecular and genetic mechanisms governing the development of lung cancer in this setting require additional study.

Biopsy↗

A retrospective study on improvements in nightmares and post-traumatic stress disorder following treatment for co-morbid sleep-disordered breathing.

OBJECTIVE: To assess the impact of treatment for co-morbid sleep-disordered breathing (SDB) on patients with nightmares and post-traumatic stress. METHODS: Twenty-three chronic nightmare sufferers (15 with post-traumatic stress disorder, PTSD) who also suffered co-morbid SDB (obstructive sleep apnea, OSA, n=16; upper airway resistance syndrome, UARS, n=7) completed a telephone interview, on average, 21 months after having been offered treatment for SDB at a university sleep disorders clinic. RESULTS: At follow-up, 14 reported maintaining treatment (Treatment Group) and 9 reported discontinuing treatment (No-Treatment Group). More patients in the Treatment Group reported improvement in sleep (93% vs. 33%) and in daytime well being (93% vs. 33%) compared with those in the No-Treatment group. The Treatment Group reported a median improvement in nightmares of 85% compared with a median 10% worsening in the No-Treatment Group. In the PTSD subset (n=15), nine in the Treatment Group reported a median 75% improvement in PTSD symptoms whereas six in the No-Treatment Group reported a median 43% worsening. CONCLUSION: In this small sample of patients, treatment of SDB was associated with improvements in nightmares and PTSD. Relationships between nightmares, PTSD and SDB are discussed.

Adult↗

A controlled study of imagery rehearsal for chronic nightmares in sexual assault survivors with PTSD: a preliminary report.

Imagery-rehearsal therapy for chronic nightmares was assessed in a randomized, controlled study of sexual assault survivors with posttraumatic stress disorder (PTSD). Nightmares, sleep quality, and PTSD were assessed at baseline for 169 women, who were randomized into two groups: treatment (n = 87) and wait-list control (n = 82). Treatment consisted of two 3-hr sessions and one 1-hr session conducted over 5 weeks. Of 169 participants, 91 women (Treatment, n = 43, Control, n = 48) completed a 3-month follow-up and 78 did not. At follow-up, nightmare frequency and PTSD severity decreased and sleep quality improved in the treatment group with small to minimal changes in the control group. Treatment effects were moderate to high (Cohen's d ranged from 0.57 to 1.26). Notwithstanding the large dropout rate, imagery-rehearsal therapy is an effective treatment for chronic nightmares in sexual assault survivors with PTSD and is associated with improvement in sleep quality and decreases in PTSD severity.

Adult↗

Sleep disorder, depression, and suicidality in female sexual assault survivors.

The role of sleep in psychiatric illness in general, and depression and suicidality in particular, is poorly understood and has not been well researched despite the pervasiveness of sleep complaints in these conditions. As an exploratory, hypothesis-generating study, female sexual assault survivors with posttraumatic stress disorder (n = 153) who had enrolled in a nightmare-treatment program were assessed for subjectively determined sleep breathing and sleep movement disorders. Diagnoses of potential disorders were based on clinical practice parameters and research algorithms from thefield of sleep disorders medicine. Potential sleep breathing and sleep movement disorders were present in 80% of the participants (n = 123) and included three subgroups: sleep-disordered breathing only (n = 23); sleep movement disorder only (n = 45); and both sleep disorders (n = 55). Based on the Hamilton Depression Rating Scale and Suicide subscale, participants with potential sleep disorders suffered greater depression (Cohen's d = .73-.96; p < .01) and greater suicidality (Cohen's d = .57-.78; p < .05) in comparison to participants without potential sleep disorders. The group with both sleep disorders suffered from the most severe depression and suicidality. A provisional hypothesis is formulated that describes how sleep disorders may exacerbate depression and suicidality through the effects of chronic sleep fragmentation.

Depression↗

Pornography and sexual aggression: are there reliable effects and can we understand them?

In response to some recent critiques, we (a) analyze the arguments and data presented in those commentaries, (b) integrate the findings of several metaanalytic summaries of experimental and naturalistic research, and (c) conduct statistical analyses on a large representative sample. All three steps support the existence of reliable associations between frequent pornography use and sexually aggressive behaviors, particularly for violent pornography and/or for men at high risk for sexual aggression. We suggest that the way relatively aggressive men interpret and react to the same pornography may differ from that of nonaggressive men, a perspective that helps integrate the current analyses with studies comparing rapists and nonrapists as well as with cross-cultural research.

Aggression↗

Inhibition of rabbit duodenal bicarbonate secretion by ulcerogenic agents: histamine-dependent and -independent effects.

BACKGROUND & AIMS: The gastroduodenal epithelium is protected from acid-peptic damage, in part, by its ability to secrete bicarbonate. Patients with duodenal ulcer disease have impaired proximal duodenal mucosal bicarbonate secretion. We have shown in vitro that histamine inhibits prostaglandin-stimulated bicarbonate secretion in rabbit duodenal mucosa via histamine H2 receptors and enteric nerves. In this study we examined whether the proulcerogenic compounds aspirin or ethanol regulate duodenal bicarbonate secretion and the involvement of histamine. METHODS: Bicarbonate secretion by rabbit proximal duodenal mucosa was examined in vitro in Ussing chambers. RESULTS: Aspirin and ethanol decreased basal and prostaglandin-stimulated bicarbonate secretion; the latter effect was specific for prostaglandin. The inhibitory effects of the two ulcerogenic compounds were at least additive. Ranitidine and tetrodotoxin abolished the inhibitory effects on stimulated, but not basal, secretion. Aspirin and ethanol also induced release of duodenal histamine. CONCLUSIONS: Aspirin and ethanol act by two distinct pathways to impair duodenal bicarbonate secretion. Both agents inhibit basal secretion via a histamine-independent and neurally independent pathway while they inhibit prostaglandin E2-stimulated secretion via histamine release, likely from mast cells, and actions on enteric nerves. Our findings may be of relevance to the understanding and potential treatment of nonsteroidal anti-inflammatory drug-associated mucosal injury.

Animals↗

A limited renal injury may cause a permanent form of neurogenic hypertension.

Previously, we have shown that an acute injury to the kidney produced by an intrarenal injection of phenol causes an immediate increase in blood pressure and in norepinephrine (NE) secretion from the posterior hypothalamus. The studies suggest that in this model afferent impulses from the kidney to central integrative structures in the brain may be responsible for the increase in blood pressure. To further evaluate whether a renal injury caused by the intrarenal injection of phenol leads to a permanent elevation of blood pressure and whether this is mediated by increased sympathetic nervous system activity, we examined the chronic effects (4 weeks) of an intrarenal injection of 50 microL of 10% phenol on blood pressure and NE secretion from the posterior hypothalamus. Systolic blood pressure increased from 128 +/- 2.1 to 176 +/- 1.5 mm Hg (P < .01) 4 weeks after receiving the intrarenal injection of phenol, but it did not change in rats that received the vehicle (128 +/- 2.4 and 135 +/- 1.7 mm Hg) and in rats that were subjected to renal denervation (127 +/- 3.4 and 124 +/- 1.0 mm Hg). The secretion of NE from the posterior hypothalamic nuclei was greater (P < .01) in rats that received phenol (253 +/- 9.6 pg/mL) than in controls (158 +/- 8.6 pg/mL) and denervated rats (170 +/- 2.1 pg/mL). These studies have shown that a limited injury to one kidney may cause a permanent elevation of blood pressure and this is associated with increased sympathetic nervous system activity.

Animals↗

T-cell derived cytokines co-stimulate proliferation of CD40-activated germinal centre as well as follicular lymphoma cells.

Follicular lymphomas, the malignant counterparts of normal germinal centre (GC) B-cells, grow in vivo in close association with polyclonal T-cells, predominantly from the T-helper cell type. T-cell-derived growth factors are involved in the development of GC B-cells. However, their role in the pathogenesis of follicular lymphomas has not been clearly defined. We investigated the co-stimulatory activity of 14 cytokines (interleukin-1 to -8, IL-10, IL-13, INF-alpha, TNF-alpha, GM-CSF and SCF) on the proliferation of CD40-activated follicular lymphoma cells in comparison to tonsillar GC B-cells. Tonsillar GC B-cells (n = 4), malignant cells from diagnostic lymph node biopsies of patients with follicular (n = 4) or transformed (n = 4) lymphomas were grown on irradiated CD40-ligand transfectants, with and without cytokines. [3H]-thymidine uptake was measured at day 7. IL-10 and IL-4 proved to be the most potent co-stimulators of proliferation of tonsillar GC B-cells, whereas proliferation of follicular lymphoma cells was co-stimulated by IL-4. The fact that IL-4 is a T-cell derived cytokine, suggests that lymphoma infiltrating T-cells play a role in the growth of these malignancies. Moreover, proliferation of both non-neoplastic tonsillar GC B-cells and follicular lymphomas is co-stimulated by T-cell derived cytokines, indicating that responsiveness to paracrine factors may not be a characteristic of the malignant phenotype.

3T3 Cells↗

Does the study of victimization revictimize the victims?

Although the number of questionnaire surveys examining the sequelae of prior sexual and physical victimization has increased over the last decade, little attention has been given to understanding the impact of such studies on participants. As part of a larger study of long-term effects of prior sexual and physical victimization, 500 randomly selected women in an HMO received a comprehensive questionnaire including multiple symptomatic distress measures and several items inquiring into previous history of sexual, physical, and emotional abuse and neglect. They also completed a short rating scale asking about their reactions to completing the questionnaire. Despite the sensitive content, the women who participated generally found the experience to be a positive one. Only a small number of women were more upset than they had anticipated, but the vast majority felt they would have completed the survey even if they had known in advance how they would feel. The subset of women who did express distress was significantly different from the group that did not, with respect to other measures of symptomatic distress and trauma exposure. These data suggest that surveys that inquire into prior episodes of childhood victimization are generally well tolerated by women who participate, and that, although a small number may be disturbed by these investigations, in general, adverse reactions may be less common than previously anticipated.

Adult↗

Nonspecific interstitial pneumonitis mimicking Pneumocystis carinii pneumonia.

Bronchoalveolar lavage (BAL) and transbronchial biopsies from 351 human immunodeficiency virus (HIV)-positive patients with presumed Pneumocystis pneumonia were analyzed to determine the spectrum and frequency of interstitial lung disease mimicking Pneumocystis pneumonia. Among 67 patients without Pneumocystis, nonspecific interstitial pneumonitis (NSIP) was the most common histologic diagnosis (n = 16). Tissue sections from patients with NSIP were tested by in situ hybridization for Epstein-Barr virus, cytomegalovirus (CMV), and HIV; sections were also tested with the polymerase chain reaction (PCR) for HIV env and gag protein DNA. In patients with NSIP, Epstein-Barr virus and CMV could not be detected by in situ hybridization; HIV nucleic acid was amplifiable with PCR in 10 of 15 formalin-fixed, paraffin-embedded tissue sections. Symptoms, physical findings, and blood gas values were similar in patients with NSIP and matched controls with Pneumocystis. Patients with NSIP presented earlier in the course of HIV, with higher weight, serum albumin levels, and CD4+ T-lymphocyte counts (492 +/- 828 cells/mm3 versus 57 +/- 60 cells/mm3), and more normal lactate dehydrogenase (LDH) levels (280 +/- 113 IU/L versus 432 +/- 141 IU/L; means +/- SD). Seven to 10 d later, improvement in blood gas values was of similar magnitude for the two groups. Only one other unequivocal, treatable infection was diagnosed only with transbronchial biopsy. These results indicate that NSIP may be the most common diagnosis mimicking Pneumocystis pneumonia in acquired immune deficiency syndrome (AIDS), and that NSIP may improve during empiric therapy.

AIDS-Related Opportunistic Infections↗