Computed tomography scan in supine and prone positions: an alternative method to detect intramural gas in emphysematous cystitis and to evaluate efficacy after adjuvant continuous intravesical irrigation treatment.

OBJECTIVE: To evaluate the efficacy of continuous intravesical irrigation with saline plus amikacin as adjuvant therapy and to evaluate the computed tomography (CT) scan in supine and prone positions (CystoCT scan) as an alternative diagnostic and evaluation method of intramural gas in emphysematous cystitis (EC) before and after treatment. METHODS: Consecutive patients with a diagnosis of EC who were hospitalized between March 2006 and January 2011 were investigated. The diagnosis was made by CystoCT scan. Treatment consisted of intravenous antibiotics, control of concomitant diseases, and placement of a 3-way urinary catheter for continuous irrigation of 500 mg of amikacin diluted in 1 l of saline given on days 0, 3, and 7. Treatment was considered successful when there was an absence of gas in the bladder wall, the urine culture was negative, there was clinical improvement, and there was an absence of toxicity. RESULTS: Eleven patients were hospitalized with a diagnosis of EC during the study period. Four were excluded from the study, 2 due to the lack of confirmation of the diagnosis with the CystoCT scan. Treatment was successful in all patients; for 6 (86%) this was achieved in 3 days and for 1 (14%) in 7 days. No toxicity was reported. CONCLUSIONS: Continuous intravesical irrigation with saline plus amikacin as adjuvant treatment of EC is an inexpensive, effective, and safe tool that might help conventional treatment and provide a rapid recovery. The CystoCT scan is an alternative method to diagnose and evaluate intramural gas in EC patients. These findings should be challenged in a randomized, multi-centre, placebo-controlled clinical trial.

A brief history of postpolio syndrome in the United States.

This is an overview of the history of the late effects of polio in this country from 1980 to the present in the context of the broader and much longer history of acute poliomyelitis. Books, articles, conference proceedings, and other relevant historical resources that dealt with polio-related issues from January 1, 1980, through December 31, 2009, were reviewed. The mean number of articles published per year was calculated for 5-year intervals beginning in 1980; the number of postpolio support groups and polio-dedicated clinics was compiled from directories published annually by Post-Polio Health International at 5-year intervals from 1985 to 2010. Beginning in the mid-1980s, the number of articles published each year increased dramatically, peaking during the years 1995 to 1999 when a mean of 48.2 articles were published each year. This figure steadily declined over the next 14 years. Support groups and clinics showed a similar pattern of rise and fall, with a maximum of 298 support groups and 96 clinics in 1990 and a decline to 131 and 32, respectively, by 2010. During the 1980s and early 1990s, there was a period of optimism that energized research, clinical, and self-help initiatives. As the limits of these efforts became apparent during the late 1990s and early 2000s, resources and activities declined as the postpolio community continued to age and decrease in size. Regardless of these trends, there are still thousands of survivors who continue to require skilled physiatric management as they cope with advancing age and declining function.

Isotope-based inferences of skipjack tuna feeding ecology and movement in the southwestern Atlantic Ocean.

Skipjack tuna (Katsuwonus pelamis) sustain a large-scale fishery in the southwest Atlantic Ocean (SWA), but information about its foraging ecology in this region is still limited. Here we use carbon (δ13C) and nitrogen (δ15N) stable isotope analysis of muscle from individuals collected in 2017-2018 (n = 383) to quantify diet composition and characterize movement patterns. We found a relatively small degree of variation in δ13C (range: -18.9 to -16.5‰) in comparison to δ15N values (6.7-14.7‰). At higher latitudes in the southern area (30-34°S), individuals had higher mean (±SD) δ15N values (12.2 ± 1.3‰) in comparison to those collected in the northern area (9.7 ± 1.5‰) between 20-26°S. At the northern area, isotope mixing models with informative priors showed that lanternfish (median: 50%) and krill (31%) were the primary foods. In the southern area, lanternfish (53%), krill (23%) and small pelagic fish (23%) were the primary food sources. Spatial shifts in diet composition were related to warming events that likely resulted in low abundance of sardines in the northern area. The latitudinal pattern in skipjack and krill δ15N values mirrored that of regional zooplankton isoscapes, suggesting residency at the timescale of isotopic turnover for muscle (~2-4 months), and that geographical variation in the baseline isotopic composition can be exploited to characterize seasonal movements of skipjack and other top marine consumers in this region.

Serotypes and Clonal Composition of Streptococcus pneumoniae Isolates Causing IPD in Children and Adults in Catalonia before 2013 to 2015 and after 2017 to 2019 Systematic Introduction of PCV13.

The goal of this study was to investigate the distribution of serotypes and clonal composition of Streptococcus pneumoniae isolates causing invasive pneumococcal disease (IPD) in Catalonia, before and after systematic introduction of PCV13. Pneumococcal strains isolated from normally sterile sites obtained from patients of all ages with IPD received between 2013 and 2019 from 25 health centers of Catalonia were included. Two study periods were defined: presystematic vaccination period (2013 and 2015) and systematic vaccination period (SVP) (2017 to 2019). A total of 2,303 isolates were analyzed. In the SVP, there was a significant decrease in the incidence of IPD cases in children 5 to 17 years old (relative risk [RR] 0.61; 95% confidence interval [CI] 0.38 to 0.99), while there was a significant increase in the incidence of IPD cases in 18- to 64-year-old adults (RR 1.33; 95% CI 1.16 to 1.52) and adults over 65 years old (RR 1.23; 95% CI 1.09 to 1.38). Serotype 8 was the major emerging serotype in all age groups except in 5- to 17-year-old children. In children younger than 5 years old, the main serotypes in SVP were 24F, 15A, and 3, while in adults older than 65 years they were serotypes 3, 8, and 12F. A significant decrease in the proportions of clonal complexes CC156, CC191, and ST306 and an increase in those of CC180, CC53, and CC404 were observed. A steady decrease in the incidence of IPD caused by PCV13 serotypes indicates the importance and impact of systematic vaccination. The increase of non-PCV13 serotypes highlights the need to expand serotype coverage in future vaccines and rethink vaccination programs for older adults. IMPORTANCE We found that with the incorporation of the PCV13 vaccine, the numbers of IPD cases caused by serotypes included in this vaccine decreased in all of the age groups. Still, there was an unforeseen increase of the serotypes not included in this vaccine causing IPD, especially in the >65-year-old group. Moreover, a significant increase of serotype 3 included in the vaccine has been observed; this event has been reported by other researchers. These facts call for the incorporation of more serotypes in future vaccines and a more thorough surveillance of the dynamics of this microorganism.

A colorful approach towards developing new nano-based imaging contrast agents for improved cancer detection.

Providing physicians with new imaging agents to help detect cancer with better sensitivity and specificity has the potential to significantly improve patient outcomes. Development of new imaging agents could offer improved early cancer detection during routine screening or help surgeons identify tumor margins for surgical resection. In this study, we evaluate the optical properties of a colorful class of dyes and pigments that humans routinely encounter. The pigments are often used in tattoo inks and the dyes are FDA approved for the coloring of foods, drugs, and cosmetics. We characterized their absorption, fluorescence and Raman scattering properties in the hopes of identifying a new panel of dyes that offer exceptional imaging contrast. We found that some of these coloring agents, coined as "optical inks", exhibit a multitude of useful optical properties, outperforming some of the clinically approved imaging dyes on the market. The best performing optical inks (Green 8 and Orange 16) were further incorporated into liposomal nanoparticles to assess their tumor targeting and optical imaging potential. Mouse xenograft models of colorectal, cervical and lymphoma tumors were used to evaluate the newly developed nano-based imaging contrast agents. After intravenous injection, fluorescence imaging revealed significant localization of the new "optical ink" liposomal nanoparticles in all three tumor models as opposed to their neighboring healthy tissues (p < 0.05). If further developed, these coloring agents could play important roles in the clinical setting. A more sensitive imaging contrast agent could enable earlier cancer detection or help guide surgical resection of tumors, both of which have been shown to significantly improve patient survival.

Identification of viral infections in the prostate and evaluation of their association with cancer.

BACKGROUND: Several viruses with known oncogenic potential infect prostate tissue, among these are the polyomaviruses BKV, JCV, and SV40; human papillomaviruses (HPVs), and human cytomegalovirus (HCMV) infections. Recently, the Xenotropic Murine Leukemia Virus-related gammaretrovirus (XMRV) was identified in prostate tissue with a high prevalence observed in prostate cancer (PC) patients homozygous for the glutamine variant of the RNASEL protein (462Q/Q). Association studies with the R462Q allele and non-XMRV viruses have not been reported. We assessed associations between prostate cancer, prostate viral infections, and the RNASEL 462Q allele in Mexican cancer patients and controls. METHODS: 130 subjects (55 prostate cancer cases and 75 controls) were enrolled in the study. DNA and RNA isolated from prostate tissues were screened for the presence of viral genomes. Genotyping of the RNASEL R462Q variant was performed by Taqman method. RESULTS: R/R, R/Q, and Q/Q frequencies for R462Q were 0.62, 0.38, and 0.0 for PC cases and 0.69, 0.24, and 0.07 for controls, respectively. HPV sequences were detected in 11 (20.0%) cases and 4 (5.3%) controls. XMRV and HCMV infections were detected in one and six control samples, respectively. The risk of PC was significantly increased (Odds Ratio = 3.98; 95% CI: 1.17-13.56, p = 0.027) by infection of the prostatic tissue with HPV. BKV, JCV, and SV40 sequences were not detected in any of the tissue samples examined. CONCLUSIONS: We report a positive association between PC and HPV infection. The 462Q/Q RNASEL genotype was not represented in our PC cases; thus, its interaction with prostate viral infections and cancer could not be evaluated.

The use of Butea superba (Roxb.) compared to sildenafil for treating erectile dysfunction.

OBJECTIVE: To evaluate the effect of an extract of Butea superba (Roxb.) (BS) compared to sildenafil for treating erectile dysfunction (ED). PATIENTS AND METHODS: An open label study was carried out among 32 men with organic ED to evaluate the response on the International Index of Erectile Function 5 (IIEF-5) to BS, a 'natural health' product (100 mg), compared to 50 mg of sildenafil (a phosphodiesterase-5 inhibitor). After a 1-week wash-out, responders to BS received either 100 mg starch or 100 mg of another batch of BS (double-blind). RESULTS: Of the patients in the BS group, 27 (84%) responded positively, compared with 26 (81%) in the sildenafil group. When assessing the score alone, 12 (38%) had a better score after taking BS, compared to seven (22%) after sildenafil, and eight (25%) had the same score. The results were surprising and could not be repeated in the double-blind part of the study, where no effect of BS was recorded. CONCLUSIONS: A 'natural' health product containing BS was more effective than sildenafil in the first part of the study, but in the second, using another batch of BS, the positive result could not be repeated and no effect was recorded. The conclusion is that the first preparation of BS was most likely blended with a phosphodiesterase-5 inhibitor, later confirmed by the supplier of BS (a natural health products company) after their own analysis.

Prospective study of prostate cancer's detection rate at our hospital in Northeast Mexican patients with PSA values between 2.6 y 4 ng/ml.

UNLABELLED: SUMMAR OBJECTIVES: To find the detection rate of prostate cancer (PCa) in our population with PSA values between 2.6 and 4 ng/ml. METHODS: We included 33 consecutive patients with a median age of 66 years, that had a Transrectal Ultrasound (TRUS) guided biopsy with PSA between 2.6-4 ng/ml. Patients were divided into 2 groups. Group 1: patients with normal Digital Rectal Examination (DRE) and Group 2: Patients with DRE with asymmetry not definitive of PCa. EXCLUSION CRITERIA: known history of PCa, intraepithelial neoplasia or Positive DRE. Statistical analysis/ Chi square, t-student and Fischer exact test. RESULTS: Twenty eight percent of the patients had positive biopsy for PCa. Fifty six percent were Gleason 6 and 44% Gleason 7. Group 1 had 59%(20) and Group 2 41% (13) in. In Group 1 16% had positive biopsy for PCa vs 46% in group 2 (p 0.04) RR 3.07. CONCLUSIONS: There are traces that the detection rate in our population could be lower in comparison with what has been reported in the literature. DRE is crucial in the initial evaluation; asymmetry could increase 3 fold the risk of having PCa.

Characterization of a novel automated microfiltration device for the efficient isolation and analysis of circulating tumor cells from clinical blood samples.

The detection and analysis of circulating tumor cells (CTCs) may enable a broad range of cancer-related applications, including the identification of acquired drug resistance during treatments. However, the non-scalable fabrication, prolonged sample processing times, and the lack of automation, associated with most of the technologies developed to isolate these rare cells, have impeded their transition into the clinical practice. This work describes a novel membrane-based microfiltration device comprised of a fully automated sample processing unit and a machine-vision-enabled imaging system that allows the efficient isolation and rapid analysis of CTCs from blood. The device performance was characterized using four prostate cancer cell lines, including PC-3, VCaP, DU-145, and LNCaP, obtaining high assay reproducibility and capture efficiencies greater than 93% after processing 7.5 mL blood samples spiked with 100 cancer cells. Cancer cells remained viable after filtration due to the minimal shear stress exerted over cells during the procedure, while the identification of cancer cells by immunostaining was not affected by the number of non-specific events captured on the membrane. We were also able to identify the androgen receptor (AR) point mutation T878A from 7.5 mL blood samples spiked with 50 LNCaP cells using RT-PCR and Sanger sequencing. Finally, CTCs were detected in 8 out of 8 samples from patients diagnosed with metastatic prostate cancer (mean ± SEM = 21 ± 2.957 CTCs/mL, median = 21 CTCs/mL), demonstrating the potential clinical utility of this device.

Population based prostate cancer screening in north Mexico reveals a high prevalence of aggressive tumors in detected cases.

BACKGROUND: Prostate Cancer (PCa) is the second most frequent neoplasia in men worldwide. Previous reports suggest that the prevalence of PCa in Hispanic males is lower than in Africans (including communities with African ancestry) and Caucasians, but higher than in Asians. Despite these antecedents, there are few reports of open population screenings for PCa in Latin American communities. This article describes the results of three consecutive screenings in the urban population of Monterrey, Mexico. METHODS: After receiving approval from our University Hospital's Internal Review Board (IRB), the screening was announced by radio, television, and press, and it was addressed to male subjects over 40 years old in general. Subjects who consented to participate were evaluated at the primary care clinics of the University Health Program at UANL, in the Metropolitan area of Monterrey. Blood samples were taken from each subject for prostate specific antigen (PSA) determination; they underwent a digital rectal examination (DRE), and were subsequently interviewed to obtain demographic and urologic data. Based on the PSA (>4.0 ng/ml) and DRE results, subjects were appointed for transrectal biopsy (TRB). RESULTS: A total of 973 subjects were screened. Prostate biopsy was recommended to 125 men based on PSA values and DRE results, but it was performed in only 55 of them. 15 of these biopsied men were diagnosed with PCa, mostly with Gleason scores > or = 7. CONCLUSION: Our results reflect a low prevalence of PCa in general, but a high occurrence of high grade lesions (Gleason > or = 7) among patients that resulted positive for PCa. This observation remarks the importance of the PCa screening programs in our Mexican community and the need for strict follow-up campaigns.

Feasibility study of home care wound management using telemedicine.

OBJECTIVE: Evaluate the effectiveness of telemedicine (TM) with digital cameras in treating wounds in a home care setting. DESIGN: Randomized controlled study. PARTICIPANTS AND SETTING: One hundred three subjects with 160 pressure ulcers (PrUs) or nonhealing surgical wounds referred to a metropolitan Visiting Nurse Agency. INTERVENTIONS: Subjects were randomly assigned to 1 of 3 groups. Group A (n = 40): weekly visits with TM and wound care specialist (WCS) consults; group B (n = 28): weekly visits with weekly consults with WCSs; and group C (n = 35): usual and customary care. MAIN OUTCOME MEASURES: Outcome measures were time to heal, costs, length of stay (LOS), nursing visits, wound status, and change in size. RESULTS: There was a similar distribution of subject characteristics in all 3 groups, but group A had disproportionally larger and more numerous PrUs and larger nonhealing surgical wounds. Group A had increased time to heal, LOS, costs, and visits compared with groups B and C; wound status was similar in all groups. CONCLUSIONS: Uneven distribution of severity and type of wounds among groups, with greatest percentage of large wounds in TM group. Larger wounds consume more resources. TM is a useful communication tool in wound management but with limited power when randomization does not include wound size or type. Two important benchmarks were established for home care. First, it took 51 days, on average, to heal or improve PrUs and 34 days to heal or improve surgical wounds regardless of group. Second, nearly 90% of wounds improved or healed.

[Does circumcision affect male's perception of sexual satisfaction?]. / Genitoplastia feminizante en hiperplasia suprarrenal congénita; una o dos etapas quirúrgicas?

SUMMARY OBJECTIVES: To evaluate the effect of circumcision on sexual satisfaction perception in males with stable sexual partners. METHODS: Twenty two heterosexual male adults, sexually active with a stable partner, scheduled for circumcision for medical (MR) or esthetic reasons (ER) at our clinic between June 2005 and June 2006 were included in this study. Men with severe erectile dysfunction (ED) were excluded from the study. These men were surveyed to assess erectile function, penile sensitivity, esthetical penis' appearance, sexual activity and overall satisfaction before the procedure and 12 weeks after. Categorical scores were evaluated with Chi square. RESULTS: Surgical indications were: Phimosis 50%, balanitis 18.2%, condyloma 13.6% and esthetics 13.6%. After the procedure 82% of patients referred an upgrade on the quality of their sexual intercourse, 4.5% referred it diminished and 13.5% referred no change at all. 95.5% of the patients felt better with the appearance of their penis. Almost all areas of sexual satisfaction weren't statistical significant except for the improvement in erectile function (p 0.0007) and perception of sexual events (p 0.04). This improvement on erectile function was reported as shifts from mild to normal on International Index of Erectile Function 5 scores. Premature ejaculation was observed in 31.8%(7) before the procedure and diminished to 13.6%(3). CONCLUSION: Because of our statistic limitations and mix indications for circumcision in the study, we cannot conclude that circumcision might bring certain benefit on sexual satisfaction by itself but certainly does not bring deleterious effects and, when dissatisfaction is associated with local problems, some benefit could be expected.

High-Throughput Automated Microscopy of Circulating Tumor Cells.

Circulating tumor cells (CTCs) have the potential of becoming the gold standard marker for cancer diagnosis, prognosis and monitoring. However, current methods for its isolation and characterization suffer from equipment variability and human operator error that hinder its widespread use. Here we report the design and construction of a fully automated high-throughput fluorescence microscope that enables the imaging and classification of cancer cells that were labeled by immunostaining procedures. An excellent agreement between our machine vision-based approach and a state-of-the-art microscopy equipment was achieved. Our integral approach provides a path for operator-free and robust analysis of cancer cells as a standard clinical practice.

Effect of a moderately hypoenergetic Mediterranean diet and exercise program on body cell mass and cardiovascular risk factors in obese women.

OBJECTIVE: To assess the effects of a moderately hypoenergetic Mediterranean diet (MHMD) and exercise program on body cell mass (BCM) and cardiovascular disease risk factors in obese women. SUBJECTS/METHODS: Forty-seven obese women, 39.7+/-13.2 years of age, with a body mass index (BMI)=30.7+/-6.0 kg/m(2), completed the study. The following were measured at baseline, 2 and 4 months: BCM, BCM index (BCMI), body weight, BMI, fat-free mass (FFM), fat mass (FM), total body water (TBW), extracellular water (ECW) and intracellular water (ICW) using bioelectrical impedance analysis; fasting blood glucose (FBG), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) concentrations; systolic (SBP) and diastolic (DBP) blood pressure. RESULTS: Body weight, BMI, FM, TC and TG significantly decreased (P<0.001; P<0.002 (TG)) at 2 and 4 months. FFM, TBW, ECW, FBG and DBP significantly decreased at 2 months (P<0.05 (FFM); P<0.001). LDL-C significantly decreased (P<0.001), while HDL-C significantly increased (P<0.002) at 4 months. BCM, BCMI, ICW and SBP remained stable over time. CONCLUSION: BCM was preserved and cardiovascular disease risk factors improved in obese women placed on a MHMD and exercise program for 4 months.

[Does circumcision has an effect on female's perception of sexual satisfaction?]. / Tiene algún efecto la circuncisión en la percepción de la satisfacción sexual de la mujer?

OBJECTIVE: To evaluate sexual satisfaction on women who have experienced sexual intercourse with the same partner on non-circumcised and circumcised states. MATERIAL AND METHODS: A total of 19 women between 19 and 53 y/o, median age 30, in which their sexual partner was programmed for circumcision were included in this study. The survey was a validated version on the Changes on Sexual Functioning Questionnaire (CSFQ). General sexual satisfaction, pain during vaginal penetration, desire, vaginal orgasm, vaginal lubrication, sexual frequency changes in oral and/or anal sexual activities and esthetical perception on circumcised penis were surveyed before the procedure and 2 months after. RESULTS: Changes on Vaginal lubrication during intercourse were significant (p = 0.004), it diminished from 78% to 63%. There were no statistically significant differences on general sexual satisfaction, pain during vaginal penetration, desire, vaginal orgasm. CONCLUSIONS: Circumcision has either negative or positive effect on female's partner perception of sexual satisfaction.

Erectile dysfunction treated with intracavernous stem cells: A promising new therapy?

In the past decades, great interest has been shown in the development of new therapies for erectile dysfunction. Stem cell therapy has generated promising results in numerous preclinical trials in animal models, which is why has led to the development of the first clinical trials in humans. The main cause involved in the pathophysiology of erectile dysfunction is vascular damage related to endothelial and neuronal injury. The interest in stem cell therapy is justified by their capability to differentiate into specific damaged tissues, including endothelium and nervous tissue, and induction of the host own cell proliferation. Despite the great effort of the many studies carried out to date, knowledge about biological effects, therapeutic efficacy and safety of stem cells therapy for erectile dysfunction is still very limited.

[Use of tadalafil in the rehabilitation of patients with a history of posterior urethral injury in the context of pelvic fracture]. / Uso de tadalafilo en la rehabilitación de pacientes con antecedente de lesión de uretra posterior en el contexto de fractura pélvica.

OBJECTIVE: To evaluate the tadalafil effect in the treatment of erectile dysfunction as a consequence of posterior urethral injury. MATERIAL AND METHODS: This is a retrospective study that included patients with posterior urethral injury caused by previous pelvic fracture; our patients received emergency urethral alignment and urethroplasty between 8 to 10weeks after trauma. To assess the degree of erectile dysfunction pre- and post-treatment, we applied the questionnaire of International Index of Erectile Function (IIEF-5). Statistics Wilcoxon test and descriptive statistics were performed. RESULTS: Eight patients were included in this study, with an average age of 32.5years; the IIEF scale prior to treatment was on average 8.5 points and increased to 12.36 points with a value of P=.011. DISCUSSION: These eight patients showed erectile dysfunction at the time of IIEF assessment, this due to emergency urethral realignment arising from the trauma caused by pelvic fracture. Treatment with inhibitors of 5-phosphodiesterase (iPDE5) is the first-line treatment in patients with erectile dysfunction because it is efficient, non-invasive and well tolerated. In this study we found results indicating good response to this treatment in 7 out of the 8 patients (87.5%). Only one patient showed no improvement after treatment, due to the presence of risk factors such as age (65years), tobacco use, and high blood pressure. CONCLUSION: The 87.5% of patients with urethral injury medicated with tadalafil were rehabilitated.

Radar evidence of subglacial liquid water on Mars.

The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

Immunological and virological studies of natural SIV infection of disease-resistant nonhuman primates.

Nonhuman primates naturally infected with simian immunodeficiency virus (SIV), while maintaining chronic viremia, do not develop any disease associated with lentiviral infection. Thus they provide a unique model to define the mechanism(s) by which they remain infected but disease-resistant. The purpose of this article is to summarize our current knowledge of the virological and immunological studies that have been performed in sooty mangabeys naturally infected with SIVsmm and in disease-susceptible rhesus macaques experimentally infected with SIVsmm. Data on virological studies demonstrate that the naturally infected sooty mangabeys are infected predominantly with SIV that have nef sequences distinct from those shown to cause disease in the inappropriate host, a factor which may contribute to disease resistance. Hyperimmunization with a variety of antigens or chronic infection contributes to accelerated disease and death in rhesus macaques if hyperimmunizations are initiated at the time of SIV infection, whereas similar hyperimmunization and chronic infection do not lead to disease in naturally infected seropositive sooty mangabeys. However, in both species infected with SIV, hyperimmunization leads to increased virus load, suggesting that virus load per se cannot account for disease, at least in naturally infected nonhuman primates. Immunological studies concerning changes in subsets of T cells, based on cytokine profile (TH0/TH1/TH2), showed that whereas rhesus macaques early post SIV infection show a dominant TH1 profile, this profile rapidly changes to TH0. On the other hand, mangabeys continuously demonstrate a TH2-like profile. Studies also showed a high frequency of in vivo-activated cells in the peripheral blood of SIV-infected rhesus macaques and mangabeys. Of interest, however, is the finding of a similar level of in vivo-activated cells from ELISA seronegative mangabeys. Although cells from SIV-infected mangabeys fail to show increased levels of apoptotic cells following incubation with immobilized anti-CD3, PBMC from rhesus macaques at varying time intervals do show increased levels of apoptotic cells, an increase which is predominantly seen in CD8+ T cells and is unrelated to levels of viremia. Sooty mangabeys maintain a high frequency of CD8+ T cells that regulate virus replication throughout their lifetime, a frequency that develops prior to ELISA-based seroconversion, whereas rhesus macaques only show a frequency of CD8+ T cells high enough to regulate virus replication shortly post infection, and this regulatory function is gradually lost prior to CD8+ cell loss and death. HIV and SIV infection do have profound effects on the expression of a number of costimulatory and adhesion molecules. There appear to be differences in the nature of the intracellular phosphorylated proteins in cells from activated rhesus macaques and mangabeys. We believe that careful studies of the detailed mechanisms of the issues described above may provide an understanding of the constellation of virological and immunological mechanisms responsible for the disease-resistant state of naturally infected sooty mangabeys. These findings can be employed for evaluating a nonvirus sterilizing form of SIV/HIV vaccines.