Toxicity and human health assessment of an alcohol-to-jet (ATJ) synthetic kerosene developed under an international agreement with Sweden.

Alcohol-to-jet (ATJ) Synthetic Kerosene with Aromatics (SKA) fuels are produced by dehydration and refining of alcohol feed stocks. ATJ SKA fuel known as SB-8 was developed by Swedish Biofuels as a cooperative agreement between Sweden and AFRL/RQTF. SB-8 including standard additives was tested in a 90-day toxicity study with male and female Fischer 344 rats exposed to 0, 200, 700, or 2000 mg/m3 fuel in an aerosol/vapor mixture for 6 hr/day, 5 days/week. Aerosols represented 0.04 and 0.84% average fuel concentration in 700 or 2000 mg/m3 exposure groups. Examination of vaginal cytology and sperm parameters found no marked changes in reproductive health. Neurobehavioral effects were increased rearing activity (motor activity) and significantly decreased grooming (functional observational battery) in 2000 mg/m3 female rats. Hematological changes were limited to elevated platelet counts in 2000 mg/m3 exposed males. Minimal focal alveolar epithelial hyperplasia with increased number of alveolar macrophages was noted in some 2000 mg/m3 males and one female rat. Additional rats tested for genotoxicity by micronucleus (MN) formation did not detect bone marrow cell toxicity or alterations in number of MN; SB-8 was not clastogenic. Inhalation results were similar to effects reported for JP-8. Both JP-8 and SB fuels were moderately irritating under occlusive wrapped conditions but slightly irritating under semi-occlusion. Exposure to SB-8, alone or as 50:50 blend with petroleum-derived JP-8, is not likely to enhance adverse human health risks in the military workplace.

Suboptimal Adherence in Clinical Practice to Guidelines Recommendation to Screen for Lynch Syndrome.

BACKGROUND: Identification of Lynch syndrome (LS) followed by annual/biannual surveillance colonoscopy markedly reduces the risk of developing new colorectal cancer (CRC) among those with LS. AIMS: (1) To determine the current practice of identifying LS in the USA and Canada, and current surveillance and management practices for those diagnosed with LS; (2) to determine whether variances in current practice are physician/region dependent or influenced by ease of access to specialist clinics. METHODS: An online survey request was sent to practicing gastroenterologists through the Canadian Association of Gastroenterology and the American College of Gastroenterology. Fisher's exact tests were performed to determine the factors associated with screening for LS and separately for follow-up, surveillance, and management. RESULTS: A total of 249 participants were recruited, of which 237 were gastroenterologists and included in the analysis. Less than one-third of practicing gastroenterologists indicated that their CRC patients were undergoing screening tests to identify LS. While 42% (65/153) of participants from the USA stated that their patients were undergoing universal LS screening (i.e., among all diagnosed with CRC), only 12% (6/49) of participants from Canada reported this practice (p < 0.001). There was no difference in reported practice between the physicians that do and do not have access to hereditary clinics (35% vs. 34% testing; p = 0.54). Appropriate surveillance interval to look for CRC in patients with LS was recommended by most. CONCLUSION: This survey suggests there is a significant difference in practice between Canada and the USA in regard to identification of LS, with suboptimal practice throughout North America.

Factors Associated with Anxiety About Colonoscopy: The Preparation, the Procedure, and the Anticipated Findings.

BACKGROUND: Previous research has assessed anxiety around colonoscopy procedures, but has not considered anxiety related to different aspects related to the colonoscopy process. AIMS: Before colonoscopy, we assessed anxiety about: bowel preparation, the procedure, and the anticipated results. We evaluated associations between patient characteristics and anxiety in each area. METHODS: An anonymous survey was distributed to patients immediately prior to their outpatient colonoscopy in six hospitals and two ambulatory care centers in Winnipeg, Canada. Anxiety was assessed using a visual analog scale. For each aspect, logistic regression models were used to explore associations between patient characteristics and high anxiety. RESULTS: A total of 1316 respondents completed the questions about anxiety (52% female, median age 56 years). Anxiety scores > 70 (high anxiety) were reported by 18% about bowel preparation, 29% about the procedure, and 28% about the procedure results. High anxiety about bowel preparation was associated with female sex, perceived unclear instructions, unfinished laxative, and no previous colonoscopies. High anxiety about the procedure was associated with female sex, no previous colonoscopies, and confusing instructions. High anxiety about the results was associated with symptoms as an indication for colonoscopy and instructions perceived as confusing. CONCLUSIONS: Fewer people had high anxiety about preparation than about the procedure and findings of the procedure. There are unique predictors of anxiety about each colonoscopy aspect. Understanding the nuanced differences in aspects of anxiety may help to design strategies to reduce anxiety, leading to improved acceptance of the procedure, compliance with preparation instructions, and less discomfort with the procedure.

Does First Nations ancestry modify the association between gestational diabetes and subsequent diabetes: a historical prospective cohort study among women in Manitoba, Canada.

BACKGROUND: Over the past 30 years, the prevalence of diabetes has steadily increased among Canadians, and is particularly evident among First Nations (FN) women. The interplay between FN ancestry, gestational diabetes and the development of subsequent diabetes among mothers remains unclear. METHODS: After excluding known pre-existing diabetes, we explored whether FN ancestry may modify the association between gestational diabetes and post-partum diabetes among women in Manitoba (1981-2011) via a historical prospective cohort database study. We analysed administrative data in the Population Health Research Data Repository using Kaplan-Meier survival analysis and Cox proportional hazards regression. RESULTS: Gestational diabetes was diagnosed in 11 906 of 404 736 deliveries (2.9%), 6.7% of FN and 2.2% of non-FN pregnant women (P < 0.0001). Post-partum diabetes during ≤ 30 years follow-up was more than three times higher among FN women than among non-FN women (P < 0.0001). Diabetes developed in 76.0% of FN and 56.2% of non-FN women with gestational diabetes within the follow-up period. The hazard ratio of gestational diabetes for post-partum diabetes was 10.6 among non-FN women and 5.4 among FN women. Other factors associated with a higher risk of diabetes included lower family income among FN and non-FN women and rural/remote residences among FN women. Among non-FN women, urban residence was associated with a higher risk of diabetes. CONCLUSION: Gestational diabetes increases post-partum diabetes in FN and non-FN women. FN women had substantially more gestational diabetes or post-partum diabetes than non-FN women, partially due to socio-economic and environmental barriers. Reductions in gestational diabetes and socio-economic inequalities are required to prevent diabetes in women, particularly in FN population.

Incidence, risk factors, and outcomes associated with cytomegalovirus disease in small bowel transplant recipients.

Despite improved prophylaxis, monitoring, and more efficient immunosuppression, CMV infection remains a common opportunistic infection in transplant recipients. We assessed the incidence of CMV disease in pediatric SBT recipients, the timing of CMV disease after transplantation, and its impact on patient outcome. The medical records of 98 SBT recipients were reviewed. We performed descriptive analysis, regression analysis, and Kaplan-Meier curves to determine the time-to-event after transplantation. Fifty-three percent patients were male and 47% female, with a mean age of 38.3 months. Thirty-five percent of patients received prophylactic VGC, 55% GCV, 10% a combination of GCV/VGC, and 99% CMV immunoglobulins. A total of 24.5% recipients were CMV D+/R- (CMV serostatus donor positive/recipient negative). Seven (c. 7%) patients developed CMV disease. CMV disease was associated with 2.5 times (0.52-12.1; p = 0.25) higher rate of CMV mismatch and 11.1 times (1.3-95.9; p = 0.03) higher risk of death. CMV prophylaxis increased time-to-death (p = 0.074). Time-to-CMV disease was shorter in patients with enteritis (p < 0.0001), and CMV disease was associated with shorter time-to-death after transplantation (p = 0.001). CMV disease in SBT recipients was associated with an 11-fold mortality increase and a fourfold faster time-to-death. Time-to-death was significantly shorter with CMV enteritis.

Do behavioural differences help to explain variations in HIV prevalence in adolescents in sub-Saharan Africa?

OBJECTIVE: To compare adolescent risk factors for HIV infection in two countries with high adolescent HIV prevalence and two lower prevalence countries with the aim of identifying risk factors that may help explain differences in adolescent HIV prevalence. METHODS: Data were available from two nationally representative surveys (South Africa, Zimbabwe), two behavioural intervention trials (Tanzania, Zimbabwe) and one population-based cohort (Uganda). Data on variables known or postulated to be risk factors for HIV infection were compared. RESULTS: Few risk behaviours were markedly more common in the high HIV prevalence populations. Risk factors more common in high HIV prevalence settings were genital ulcers and discharge, and women were more likely to report older male partners. DISCUSSION: Age mixing may be an important determinate of HIV prevalence in adolescents. Potential reasons for the general lack of association between other adolescent risk factors and adolescent HIV prevalence include adult HIV prevalence, misreported behaviour, different survey methods and other unmeasured adolescent behaviours. If adult factors dominate adolescent HIV risk, it would help explain the failure of behavioural interventions targeted at adolescents and suggests future interventions should include adults.

Seroprevalence of West Nile virus infection in solid organ transplant recipients.

BACKGROUND: Of people infected with mosquito-borne West Nile virus (WNV), <1% develop neuroinvasive disease (NID). Population studies suggest that people older than 65 years may be at higher risk for neurologic symptoms. It has been suggested that solid organ transplant (SOT) recipients are also at higher risk for WNV NID, but definitive serologic and epidemiologic data are lacking. METHODS: A serologic screening survey, using a US Food & Drug Administration-approved enzyme-linked immunosorbant assay to detect WNV immunoglobulin-G (IgG) antibody responses in cohorts of SOT recipients and non-immunocompromised controls, was undertaken at a large Midwestern university organ transplant center in the aftermath of the summer 2003 WNV regional outbreak. Hemagglutination-inhibition testing was used to confirm WNV IgG-positive results and differentiate them from positive results caused by Saint Louis encephalitis virus, another flavivirus that is endemic in the Midwestern US. FINDINGS: The rate of WNV IgG-seropositive responses did not differ between SOT recipients and non-immunocompromised controls, and were 12% and 10%, respectively. Retrospective chart review showed no documented WNV NID in the seropositive SOT recipients, suggesting an incidence of WNV NID may be as low as 0.7% in this population. INTERPRETATION: Asymptomatic WNV infection is common among immunocompromised SOT patients, occurring as often as it does in non-immunocompromised controls. Our data indicated that severe WNV NID is less frequent in SOT patients, contrary to what has been suggested in other studies.

Is sexual risk taking behaviour changing in rural south-west Uganda? Behaviour trends in a rural population cohort 1993-2006.

OBJECTIVE: To describe sexual behaviour trends in a rural Ugandan cohort in the context of an evolving HIV epidemic, 1993-2006. METHODS: Sexual behaviour data were collected annually from a population cohort in which HIV serological surveys were also conducted. Behaviour trends were determined using survival analysis and logistic regression. Trends are reported based on the years in which the respective indicators were collected. RESULTS: Between 1993 and 2006, median age at first sex increased from 16.7 years to 18.2 years among 17-20-year-old girls and from 18.5 years to 19.9 years among boys. Both sexes reported a dip in age at sexual debut between 1998 and 2001. One or more casual partners in the past 12 months among men rose from 11.6% in 1997 to 12.7% in 2004 and then declined to 10.2% in 2006. Among women it increased from 1.4% in 1997 to 3.7% in 2004 and then reduced to 1.4% in 2006. The rise in casual partners between 1997 and 2004 was driven mainly by older age groups. Trends in condom use with casual partners varied by age, increasing among those aged 35+ years, declining in the middle age groups and presenting a dip and then a rise in the youngest aged group (13-19 years). CONCLUSION: Among youth, risky behaviour declined but increased in the late 1990s/early 2000s. Among those aged 35+ years, condom use rose but casual partners also rose. Several indicators portrayed a temporary increase in risk taking behaviour from 1998 to 2002.

Independent Validation of a Self-Report Version of the IBD Disability Index (IBDDI) in a Population-Based Cohort of IBD Patients.

Introduction: A new clinician-administered inflammatory bowel disease (IBD) Disability Index (IBDDI) was recently developed and validated among a population in France. We aimed to validate the IBDDI in a North American setting and adapt for use as a self-report tool. Methods: Persons 18-65 years old from the population-based University of Manitoba IBD Research Registry were mailed a self-administered survey. This survey included the IBDDI and several scales that should correlate with a disability measure- the World Health Organization (WHO) Disability Assessment Scale (WHODAS) 2.0, Work and Social Adjustment Scale (WSAS), the Inflammatory Bowel Disease Questionnaire (IBDQ), and the K6-Kessler Emotional Distress Scale. We used Pearson correlation coefficients to assess construct validity, Cronbach's alpha to assess internal consistency, and Factor analysis to assess which of the IBDDI items likely belonged to a single IBD-related disability factor. Results: In response to the survey request,1143 (46% of those contacted) participated (61% female, mean age 51, 52% with Crohn's disease). On an index scale from 0-100, 14% had a score ≥50 (extreme disability, 18% of those with Crohn's disease; 10% of those with ulcerative colitis). There were strong correlations between IBDDI and WSAS (0.76), WHODAS (0.76), K6 (0.73), and an inverse correlation with IBDQ (-0.86). The Cronbach's alpha was high (0.88). All but 2 items (number of liquid stools in the past week and arthritis/arthralgia) of the 14 identified for IBDDI loaded highly onto a single factor (factor loading > 0.40). Conclusions: The findings support the validity of this new self-report version of the IBDDI as a sound measure of disability in IBD.

Predictors of patient reluctance to wake early in the morning for bowel preparation for colonoscopy: a precolonoscopy survey in city-wide practice.

INTRODUCTION: Many endoscopists do not use split-dose bowel preparation (SDBP) for morning colonoscopies. Despite SDBP being recommended practice, they believe patients will not agree to take early morning bowel preparation (BP). We assessed patients' opinions about waking early for BP. METHODS: A self-administered survey was distributed between 08/2015 and 06/2016 to patients in Winnipeg, Canada when they attended an outpatient colonoscopy. Logistic regression was performed to determine predictors of reluctance to use early morning BP. RESULTS: Of the 1336 respondents (52 % female, median age 57 years), 33 % had used SDBP for their current colonoscopy. Of the 1336, 49 % were willing, 24 % neutral, and 27 % reluctant to do early morning BP. Predictors of reluctant versus willing were number of prior colonoscopies (OR 1.20; 95 %CI: 1.07 - 1.35), female gender (OR 1.65; 95 %CI: 1.19 - 2.29), unclear BP information (OR 1.86; 95 %CI: 1.21 - 2.85), high BP anxiety (OR 2.02; 95 %CI: 1.35 - 3.02), purpose of current colonoscopy being bowel symptoms (OR 1.40; 95 %CI: 1.00 - 1.97), use of 4 L of polyethylene glycol laxative (OR 1.45; 95 %CI: 1.02 - 2.06), not having SDBP (OR 1.96; 95 %CI: 1.31 - 2.93), and not having finished the laxative for the current colonoscopy (OR 1.66; 95 %CI: 1.01 - 2.73). Most of the same predictors were identified when reluctance was compared to willing or neutral, and in ordinal logistic regression. CONCLUSIONS: Almost three-quarters of patients do not express reluctance to get up early for BP. Among those who are reluctant, improving BP information, allaying BP-related anxiety, and use of low volume BP may increase acceptance of SDBP.

Spleen but not tumor infiltration by dendritic and T cells is increased by intravenous adenovirus-Flt3 ligand injection.

Dendritic cell (DC) expansion is regulated by the hematopoietic growth factor fms-like tyrosine kinase 3 ligand (Flt3L). DCs are critical to the control of tumor growth and metastasis, and there is a positive correlation between intratumoral DC infiltration and clinical outcome. In this report, we first demonstrate that single intravenous (i.v.) injections of adenovirus (Adv)-Flt3L significantly increased splenic dendritic, B, T and natural killer (NK) cell numbers in both normal and mammary tumor-bearing mice. In contrast, the numbers of DCs and T cells infiltrating the tumors were not increased. Consistent with the minimal effect on immune cell infiltration, i.v. Adv-Flt3L injections had no therapeutic activity against orthotopic mammary tumors. In addition, we noted tumor and Adv-Flt3L expansion of Gr1(+)CD11b(+) immature myeloid suppressor cells (IMSCs), which may inhibit the therapeutic efficacy of Adv-Flt3L-expanded DCs.

Association between active GB virus-C (hepatitis G) infection and HIV-1 disease in Uganda.

Although not linked to a disease, GB virus-C viraemia has been associated with an improved prognosis in HIV-1-co-infected individuals. Most studies have been conducted on men (men who have sex with men or injection drug users) infected with HIV-1 subtype B, whereas here we report on both male and female subjects from rural Uganda, predominantly infected via the heterosexual route with HIV-1 subtypes A and D. In a longitudinal study of 272 participants, 47 were GBV-C positive and 181 negative, as determined by reverse transcription-polymerase chain reaction, in both of two plasma samples taken a median of 5.0 years apart. The remainder either acquired (25) or cleared (19) infection. Multilevel regression analyses and Cox survival analyses revealed that participants chronically infected with GBV-C had a slower decline in CD4(+) T cells (P<0.001) and increased survival time (P=0.041) compared with GBV-C RNA-negative, HIV-positive adults. We show that the association between active GBV-C co-infection and improved survival of HIV-1-infected adults is not restricted to HIV subtype B, but is also observed in both males and females infected with HIV subtypes A and D.

Steroid-mediated inhibition of radiation-induced apoptosis in C4-1 cervical carcinoma cells is p53-dependent.

In human papillomavirus (HPV) infected cervical epithelial cells the synthetic steroid dexamethasone inhibits radiation-induced apoptosis and increases the transcription of HPV E6/E7, enhancing p53 degradation. The aim of this study was to determine if suppression of apoptosis was mechanistically linked to changes in p53. HPV 16 E6 or E6/E7 expression vectors were transiently transfected into C4-1 HPV 18-positive cervical carcinoma cells to mimic the enhanced transcription following steroid treatment. After irradiation, apoptosis was suppressed in these cells comparable to the effect observed after steroid treatment alone. To confirm whether loss of p53 was responsible for the inhibition of apoptosis, residual p53 in C4-1 cells was targeted by stable transfection with a dominant-negative p53 mutant. While radiation-induced apoptosis increased after mutant transfection, inhibition of programmed cell death by steroid treatment was either eliminated or substantially reduced. Steroid-dependent inhibition of radiation-induced apoptosis in carcinoma of the cervix involves E6 modulation of p53 expression and may adversely affect treatment.

Assessment of melatonin's ability to regulate cytokine production by macrophage and microglia cell types.

Evidence in support of melatonin's role as an immunomodulator is incomplete and, in some cases, contradictory. The present studies determined whether melatonin modulates the activity of stimulated macrophages. In vitro lipopolysaccharide (LPS, 10-1000 ng/ml) treatment of alveolar, splenic and peritoneal macrophages isolated from mice and/or rats resulted in a dose-dependent increase in interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF-alpha) secretion. Treatment with melatonin (10(-10)-10(-6) M) prior to the addition of LPS, had no effect on IL-1beta or TNF-alpha release. Additionally, melatonin had no effect on stimulated BV2 microglial cell line cytokine secretion. To determine whether melatonin had an indirect effect on macrophage cytokine release via T cells, melatonin was added to unfractionated mouse spleen cells. Again, melatonin showed no priming effect on LPS-stimulated spleen cells. These results suggest that melatonin has no direct or indirect effect on mouse and rat macrophages. In vivo studies, where melatonin was continuously available in the drinking water, showed that melatonin did not have a priming effect on LPS-stimulated mouse peritoneal macrophages. These findings suggest that melatonin is not an important modulator of macrophage and microglia function.

Gastrointestinal symptoms before and during menses in women with IBD.

BACKGROUND: It is believed that women with inflammatory bowel disease (IBD) have heightened symptoms around their menses. However, there is little information regarding normative changes and which symptoms emerge in relation to menses. AIM: To determine the relationship between gastrointestinal and other symptoms and menses in a population-based cohort of women with IBD vs. healthy women. METHODS: Women enrolled in the University of Manitoba IBD Research Registry who were between 18 and 65 years were mailed a survey. A control group of adult women were recruited through out-patient gynaecology clinics. Participants were asked to consider their menstrual periods in the recent several months and report on symptoms 1-5 days prior to and during the days of their menses. RESULTS: There were 151 premenopausal women with Crohn's disease (CD), 87 with ulcerative colitis (UC) and 156 premenopausal controls. Mean age of menses onset was similar in all three cohorts and the percentage in each group with regular menstrual periods was similar. Premenstrually, abdominal pain was less commonly reported in UC (36.8%) than CD (51%, P = 0.034) and controls (57.6%, P = 0.002). Premenstrually, and during menses diarrhoea was more commonly reported in CD (47.7% and 59.6% respectively) than UC (26.4% P = 0.001 and 42.5%, P = 0.01 respectively) and controls (24.4%, P < 0.0001 and 28.2%, P < 0.0001 respectively). Premenstrually, women with CD (46%) vs. UC (26%) were more likely to report worsening of their IBD symptoms (P = 0.0007), but there was no difference between CD (47%) and UC (39%) for reporting worsening during menses (P = 0.24). CONCLUSIONS: Compared to healthy women, women with IBD had similar symptom experiences premenstrually, except that those with CD were more likely to have increased diarrhoea premenstrually. During menses, women with CD or UC were more likely to experience diarrhoea than healthy controls.

Tat-specific binding IgG and disease progression in HIV type 1-infected Ugandans.

There are data to suggest that both the humoral and cellular immune responses directed against Tat are beneficial in delaying HIV disease progression. We examined the association between the occurrence of Tat-specific binding antibodies (Abs) and different parameters of HIV-1 disease progression. We generated eight Tat proteins, derived from HIV-1 subtypes A, B, C, and D, and circulating recombinant form CRF01_AE. These proteins were used to screen for Tat-specific binding Abs by an ELISA. Using five Tat proteins, we investigated whether the occurrence of Tat-specific Abs within 2 years after seroconversion for the majority, affected disease progression over time among 126 participants using survival analysis and rate of CD4 decline. Of these, 52 participants with a sample at 1.5 and 4.5 years after seroconversion were further examined to study the effect of Tat-specific Ab loss or maintenance on disease progression. Finally, using all the eight Tat proteins, we also investigated whether specific Abs to these Tat proteins among 48 participants, grouped as rapid progressors (RP, n = 26) and long-term survivors (LTS, n = 22) according to their CD4 decline over time, affected disease progression. Survival analysis did not reveal any evidence of protection from progression by Tat-specific Abs. Comparison of rate of CD4 declines between individuals with and without Abs to any Tat protein showed only a small and borderline significant advantage of having Tat-specific Abs (p = 0.043). There was no correlation between either loss or maintenance of Tat-specific Abs and disease progression. Comparison of LTS with RP showed no evidence that Tat-specific Abs slows participants' disease progression. This study showed no evidence of a protective effect of having Tat-specific Abs among these Ugandan subjects.

The impact of the family planning supply environment on contraceptive intentions and use in Morocco.

Although the extent to which organized family planning programs influence reproductive preferences remains a subject of debate, most observers would grant that such programs play a key role in helping individuals to realize their contraceptive and reproductive intentions. However, few prior studies have quantified the magnitude of this facilitating or enabling effect of family planning services, given existing demand for contraception. This study takes advantage of panel survey data and linked information on the supply environment for family planning services in Morocco in order to bridge this research gap. In the analysis, contraceptive use during the 1992-95 period is related to contraceptive intentions in 1992; individual-, household-, and community-level determinants of contraceptive behavior; and family planning supply factors. Estimation procedures are used that control for unobserved joint determinants of contraceptive intentions and use. Evidence of a significant enabling or facilitating role of family planning services is found, and the results also suggest that family planning program factors influence contraceptive intentions in important ways.

Human immunodeficiency virus neurotropism: an analysis of viral replication and cytopathicity for divergent strains in monocytes and microglia.

Productive replication of human immunodeficiency virus type 1 (HIV-1) in brain macrophages and microglia is a critical component of viral neuropathogenesis. However, how virus-macrophage interactions lead to neurological disease remains incompletely understood. Possibly, a differential ability of virus to replicate in brain tissue macrophages versus macrophages in other tissues underlies HIV-1 neurovirulence. To these ends, we established systems for the isolation and propagation of pure populations of human microglia and then analyzed the viral life cycles of divergent HIV-1 strains in these cells and in cultured monocytes by using identical viral inocula and indicator systems. The HIV-1 isolates included those isolated from blood, lung tissue, cerebrospinal fluids (CSF), and brain tissues of infected subjects: HIV-1(ADA) and HIV-1(89.6) (from peripheral blood mononuclear cells), HIV-1(DJV) and HIV-1(JR-FL) (from brain tissue), HIV-1(SF162) (from CSF), and HIV-1(BAL) (from lung tissue). The synthesis of viral nucleic acids and viral mRNA, cytopathicity, and release of progeny virions were assessed. A significant heterogeneity among macrophage-tropic isolates for infection of monocytes and microglia was demonstrated. Importantly, a complete analysis of the viral life cycle revealed no preferential differences in the abilities of the HIV-1 strains tested to replicate in microglia and/or monocytes. Macrophage tropism likely dictates the abilities of HIV-1 to invade, replicate, and incite disease within its microglial target cells.