Development and Validation of a Genotypic Assay to Quantify CXCR4- and CCR5-Tropic Human Immunodeficiency Virus Type-1 (HIV-1) Populations and a Comparison to Trofile®

HIV-1 typically infects cells via the CD4 receptor and CCR5 or CXCR4 co-receptors. Maraviroc is a CCR5-specific viral entry inhibitor; knowledge of viral co-receptor specificity is important prior to usage. We developed and validated an economical V3-env Illumina-based assay to detect and quantify the frequency of viruses utilizing each co-receptor. Plasma from 54 HIV+ participants (subtype B) was tested. The viral template cDNA was generated from plasma RNA with unique molecular identifiers (UMIs). The sequences were aligned and collapsed by the UMIs with a custom bioinformatics pipeline. Co-receptor usage, determined by codon analysis and online phenotype predictors PSSM and Geno2pheno, were compared to existing Trofile® data. The cost of V3-UMI was tallied. The sequences interpreted by Geno2pheno using the most conservative cut-off, a 2% false-positive-rate (FPR), predicted CXCR4 usage with the greatest sensitivity (76%) and specificity (100%); PSSM and codon analysis had similar sensitivity and lower specificity. Discordant Trofile® and genotypic results were more common when participants had specimens from different dates analyzed by either assay. V3-UMI reagents cost USD$62/specimen. A batch of ≤20 specimens required 5 h of technical time across 1.5 days. V3-UMI predicts HIV tropism at a sensitivity and specificity similar to those of Trofile®, is relatively inexpensive, and could be performed by most central laboratories. The adoption of V3-UMI could expand HIV drug therapeutic options in lower-resource settings that currently do not have access to phenotypic HIV tropism testing.

Low rate of SARS-CoV-2 incident infection identified by weekly screening PCR in a prospective year-long cohort study

Background

Asymptomatic and pre-symptomatic SARS-CoV-2 infections may contribute to ongoing community transmission, however, the benefit of routine screening of asymptomatic individuals in low-risk populations is unclear.

Methods

To identify SARS-CoV-2 infections 553 seronegative individuals were prospectively followed for 52 weeks. From 4/2020-7/2021, participants submitted weekly self-collected nasal swabs for rtPCR and completed symptom and exposure surveys.

Results

Incident SARS2-CoV-2 infections were identified in 9/553 (1.6%) participants. Comparisons of SARS2-CoV-2(+) to SARS2-CoV-2(-) participants revealed significantly more close contacts outside the household (median: 5 versus 3; p = 0.005). The incidence of infection was higher among unvaccinated/partially vaccinated than among fully vaccinated participants (9/7,679 versus 0/6,845 person-weeks; p = 0.004). At notification of positive test result, eight cases were symptomatic and one pre-symptomatic.

Conclusions

These data suggest that weekly SARS2-CoV2 surveillance by rtPCR did not efficiently detect pre-symptomatic infections in unvaccinated participants.

Implementation of an interactive mobile application to pilot a rapid assay to detect HIV drug resistance mutations in Kenya

Usability is an overlooked aspect of implementing lab-based assays, particularly novel assays in low-resource-settings. Esoteric instructions can lead to irreproducible test results and patient harm. To address these issues, we developed a software application based on "Aquarium", a laboratory-operating system run on a computer tablet that provides step-by-step digital interactive instructions, protocol management, and sample tracking. Aquarium was paired with a near point-of-care HIV drug resistance test, "OLA-Simple", that detects mutations associated with virologic failure. In this observational study we evaluated the performance of Aquarium in guiding untrained users through the multi-step laboratory protocol with little supervision. To evaluate the training by Aquarium software we conducted a feasibility study in a laboratory at Coptic Hope Center in Nairobi, Kenya. Twelve volunteers who were unfamiliar with the kit performed the test on blinded samples (2 blood specimens; 5 codons/sample). Steps guided by Aquarium included: CD4+ T-Cell separation, PCR, ligation, detection, and interpretation of test results. Participants filled out a short survey regarding their demographics and experience with the software and kit. None of the laboratory technicians had prior experience performing CD4+ separation and 7/12 had no experience performing laboratory-based molecular assays. 12/12 isolated CD4+ T cells from whole blood with yields comparable to isolations performed by trained personnel. The OLA-Simple workflow was completed by all, with genotyping results interpreted correctly by unaided-eye in 108/120 (90%) and by software in 116/120 (97%) of codons analyzed. In the surveys, participants favorably assessed the use of software guidance. The Aquarium digital instructions enabled first-time users in Kenya to complete the OLA-simple kit workflow with minimal training. Aquarium could increase the accessibility of laboratory assays in low-resource-settings and potentially standardize implementation of clinical laboratory tests.

Implementation of an interactive mobile application to pilot a rapid assay to detect HIV drug resistance mutations in Kenya

Usability is an overlooked aspect of implementing lab-based assays, particularly novel assays in low-resource-settings. Esoteric instructions can lead to irreproducible test results and patient harm. To address these issues, we developed a software application based on "Aquarium", a laboratory-operating system run on a computer tablet that provides step-by-step digital interactive instructions, protocol management, and sample tracking. Aquarium was paired with a near point-of-care HIV drug resistance test, "OLA-Simple", that detects mutations associated with virologic failure. In this observational study we evaluated the performance of Aquarium in guiding untrained users through the multi-step laboratory protocol with little supervision. To evaluate the training by Aquarium software we conducted a feasibility study in a laboratory at Coptic Hope Center in Nairobi, Kenya. Twelve volunteers who were unfamiliar with the kit performed the test on blinded samples (2 blood specimens; 5 codons/sample). Steps guided by Aquarium included: CD4+ T-Cell separation, PCR, ligation, detection, and interpretation of test results. Participants filled out a short survey regarding their demographics and experience with the software and kit. None of the laboratory technicians had prior experience performing CD4+ separation and 7/12 had no experience performing laboratory-based molecular assays. 12/12 isolated CD4+ T cells from whole blood with yields comparable to isolations performed by trained personnel. The OLA-Simple workflow was completed by all, with genotyping results interpreted correctly by unaided-eye in 108/120 (90%) and by software in 116/120 (97%) of codons analyzed. In the surveys, participants favorably assessed the use of software guidance. The Aquarium digital instructions enabled first-time users in Kenya to complete the OLA-simple kit workflow with minimal training. Aquarium could increase the accessibility of laboratory assays in low-resource-settings and potentially standardize implementation of clinical laboratory tests.

The association of stroke rate with low density lipoprotein and statin exposure in patients with atrial fibrillation (AF)

Background

There are limited data on the association between cholesterol levels and stroke risk in atrial fibrillation (AF).

Objective

To quantify the association of stroke rate in AF with low-density lipoprotein (LDL) levels and statin use.

Methods

Using linked administrative databases in Ontario, Canada, we conducted a population-based retrospective cohort study of patients aged ≥66 years, diagnosed with AF between 2009–2019. We used cause-specific hazard regression to determine the association of statin use with stroke rate. We developed a second cause-specific regression model for patients with at least one lipid profile measurement in the year before AF diagnosis to study the association of LDL levels with stroke rate, while adjusting for statin use. LDL levels were modeled using restricted cubic splines (RCS). Both models were adjusted for age, sex, heart failure, hypertension, diabetes, stroke or transient ischemic attack, and vascular disease at baseline, plus anticoagulation as a time-varying covariate.

Results

We studied 261,659 qualifying patients (median age 78 years, 49% female), of whom 3,954 (1.5%) developed a stroke during one-year follow-up. A total of 142,834 (54.6%) patients were treated with statins and 145,775 (55.7%) had lipid measurements before AF diagnosis. The adjusted RCS analyses (see Figure) indicated increasing hazard ratios (HRs) for stroke with increasing low-density lipoprotein (LDL) values above 1.5mmol/L. Statin use was associated with a lower stroke rate relative to non-users (hazard ratio 0.87, 95% confidence interval 0.81–0.93, p-value <0.0001).

Conclusion

LDL levels above 1.5mmol/L were independently associated with higher stroke rates in patients with AF, while statins were associated with lower stroke rates independent of anticoagulation. This suggests that LDL measurements may improve stroke risk stratification in AF, while statins may offer an underutilized pathway to lower stroke risk in AF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): 1) Heart and stroke foundation of Canada HR for Stroke and LDL level

Racial/ethnic differences in cardiovascular outcomes in a universal healthcare system: insights from the CARTaGENE cohort

Background

While prior studies have shown racial/ethnic differences in cardiovascular (CV) outcomes within private or mixed health care systems, it remains uncertain whether inequalities in cardiovascular outcomes exist between different races and ethnicities in universal health care contexts. We aimed to determine whether there are racial/ethnicity disparities in long-term CV outcomes within a single-payer universal health care system.

Methods

The CARTaGENE study is a population-based prospective cohort study with enrollment of 19,996 individuals between 40–69 years in 2009, in the province of Quebec, Canada. Participants residing in four large metropolitan areas were randomly chosen from the provincial health insurance registry by strata of age, sex, and postal codes. Follow-up was available up to 2016. For this analysis, we retained only participants without prior known CV disease. The primary composite endpoint was time to the first CV event or intervention (CV death, acute coronary syndrome, heart failure, coronary revascularization, ischemic stroke, or peripheral vascular event or revascularization). We used unadjusted and adjusted Cox proportional hazard models to evaluate the association of self-defined race/ethnicity with the primary endpoint.

Results

There were 17,802 eligible participants with a mean age of 51 years (52.5% females) with 111,312 person-years of follow-up (median follow-up of 6.6 years). South Asian (SA) participants had the highest prevalence of diabetes mellitus (29%) and hypertension (32%). After adjustment for age and sex, SA ethnicity was associated with a 95% relative increase in risk for CV events, while East/Southeast Asian (ESA) ethnicity was associated with a 42% relative decrease in risk for CV events compared to White participants. After further adjustment for socioeconomic status and CV risk factors, ESA ethnicity remained associated with a similar decreased CV risk. In contrast, the association of SA ethnicity with increased CV risk was attenuated after full adjustment for baseline characteristics (Table 1).

Conclusions

Racial/ethnic disparities in long-term CV outcomes are present in a single-payer universal healthcare setting. ESA ethnicity was associated with a lower risk of long-term CV outcomes. Future studies are needed to corroborate the reduced risk of long-term major CV events associated with ESA ethnicity. Understanding the reasons related to potential CV protection with ESA ethnicity could facilitate endeavors to reduce long-term CV outcomes in other races/ethnicities.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): McGill Health University Center

Maternal HIV drug resistance is associated with vertical transmission and is prevalent in infected infants

BACKGROUND

We aimed to assess if maternal HIV drug resistance is associated with an increased risk of HIV vertical transmission and to describe the dynamics of drug resistance in HIV-infected infants.

METHODS

A case-control study of PROMISE study participants. "Cases" were mother-infant pairs with HIV vertical transmission during pregnancy or breastfeeding and "controls" were mother-infant pairs without transmission matched 1:3 by delivery date and clinical site. Genotypic HIV drug resistance analyses were performed on mothers' and their infants' plasma at or near the time of infant HIV diagnosis. Longitudinal analysis of genotypic resistance was assessed in available specimens from infants, from diagnosis and beyond, including ART initiation and last study visits.

RESULTS

Our analyses included 85 cases and 255 matched controls. Maternal HIV drug resistance, adjusted for plasma HIV RNA load at infant HIV diagnosis, enrollment CD4 count, and antepartum regimens, was not associated with in utero/peripartum HIV transmission. In contrast, both maternal plasma HIV RNA load and HIV drug resistance were independent risk factors associated with vertical transmission during breastfeeding. Furthermore, HIV drug resistance was selected across infected infants during infancy.

CONCLUSIONS

Maternal HIV drug resistance and maternal viral load were independent risk factors for vertical transmission during breastfeeding, suggesting that nevirapine alone may be insufficient infant prophylaxis against drug-resistant variants in maternal breast milk. These findings support efforts to achieve suppression of HIV replication during pregnancy and suggest that breastfeeding infants may benefit from prophylaxis with a greater barrier to drug resistance than nevirapine alone.

OLA-Simple: A software-guided HIV-1 drug resistance test for low-resource laboratories

Background

HIV drug resistance (HIVDR) testing can assist clinicians in selecting treatments. However, high complexity and cost of genotyping assays limit routine testing in settings where HIVDR prevalence has reached high levels.

Methods

The oligonucleotide ligation assay (OLA)-Simple kit was developed for detection of HIVDR against first-line non-nucleoside/nucleoside reverse transcriptase inhibitors and validated on 672 codons (168 specimens) from subtypes A, B, C, D, and AE. The kit uses dry reagents to facilitate assay setup, lateral flow devices for visual HIVDR detections, and in-house software with an interface for guiding users and analyzing results.

Findings

HIVDR analysis of specimens by OLA-Simple compared to Sanger sequencing revealed 99.6 ± 0.3% specificity and 98.2 ± 0.9% sensitivity, and compared to high-sensitivity assays, 99.6 ± 0.6% specificity and 86.2 ± 2.5% sensitivity, with 2.6 ± 0.9% indeterminate results. OLA-Simple was performed more rapidly compared to Sanger sequencing (<4 h vs. 35–72 h). Forty-one untrained volunteers blindly tested two specimens each with 96.8 ± 0.8% accuracy.

Interpretation

OLA-Simple compares favorably with HIVDR genotyping by Sanger and sensitive comparators. Instructional software enabled inexperienced, first-time users to perform the assay with high accuracy. The reduced complexity, cost, and training requirements of OLA-Simple could improve access to HIVDR testing in low-resource settings and potentially allow same-day selection of appropriate antiretroviral therapy.

Fund

USA National Institutes of Health R01; the Clinical and Retrovirology Research Core and the Molecular Profiling and Computational Biology Core of the UW CFAR; Seattle Children's Research Institute; UW Holloman Innovation Challenge Award; Pilcher Faculty Fellowship.

Stool Microbiota at Neutrophil Recovery Is Predictive for Severe Acute Graft vs Host Disease After Hematopoietic Cell Transplantation

Background

Graft-versus-host disease (GVHD) is common after allogeneic hematopoietic cell transplantation (HCT). Risk for death from GVHD has been associated with low bacterial diversity in the stool microbiota early after transplant; however, the specific species associated with GVHD risk remain poorly defined.

Methods

We prospectively collected serial weekly stool samples from 66 patients who underwent HCT, starting pre-transplantation and continuing weekly until 100 days post-transplant, a total of 694 observations in HCT recipients. We used 16S rRNA gene polymerase chain reaction with degenerate primers, followed by high-throughput sequencing to assess the relative abundance of sequence reads from bacterial taxa in stool samples over time.

Results

The gut microbiota was highly dynamic in HCT recipients, with loss and appearance of taxa common on short time scales. As in prior studies, GVHD was associated with lower alpha diversity of the stool microbiota. At neutrophil recovery post-HCT, the presence of oral Actinobacteria and oral Firmicutes in stool was positively correlated with subsequent GVHD; Lachnospiraceae were negatively correlated. A gradient of bacterial species (difference of the sum of the relative abundance of positive correlates minus the sum of the relative abundance of negative correlates) was most predictive (receiver operator characteristic area under the curve of 0.83) of subsequent severe acute GVHD.

Conclusions

The stool microbiota around the time of neutrophil recovery post-HCT is predictive of subsequent development of severe acute GVHD in this study.

Abstract P1-10-02: A phase II study of copper-depletion using tetrathiomolybdate in patients with breast cancer at high risk for recurrence: Updated results

Background: Metals have emerged as a viable therapeutic target for a new generation of anti-cancer and anti-metastatic agents. Copper, an essential trace element, serves as an important catalytic cofactor in several biological functions and has emerged as an essential factor in carcinogenesis. Among other elements, bone marrow derived VEGFR2+ endothelial progenitor cells (EPCs) and copper-dependent lysyl oxidase (LOX) are key elements in tumor progression. We hypothesized tetrathiomolybdate (TM)-associated copper depletion (CD) inhibits tumor metastases by reducing the number of EPCs and other copper dependent processes in the pre-metastatic niche. These results are an update of our previously reported study (Chan N, Willis A, Kornhauser N et al. Influencing the Tumor Microenvironment: Phase 2 Study of Copper Depletion with Tetrathiomolybdate in High Risk Breast Cancer and Preclinical Models of Lung Metastases. Clin Cancer Res. October 21, 2016) with longer follow-up.

Methods: A single arm phase II study of breast cancer (BC) patients (pts) at high risk for recurrence, defined as node+ triple negative (TNBC), stage 3 and 4 with no evidence of disease (NED) were enrolled on a trial of CD with TM. TM was given to maintain ceruloplasmin (Cp) levels between 8-16 mg/dl for two years with an extension phase or until relapse. The primary endpoint was a change in EPCs measured by flow cytometry before and during treatment. Secondary endpoints included tolerability, safety, PFS and LOXL-2 levels.

Results: Seventy-five pts received 2778 cycles of TM on the primary and extension study. The primary study treatment duration was 24 cycles (each cycle is 28 days) plus an extension phase. The median age is 51 years (range 29-66). Forty-five pts have stage 2/3 BC and 30 with stage 4 NED. Forty-eight percent of pts are TNBC and 40% of pts are stage 4 NED. Median Cp levels were monitored with each cycle. A decrease from 28 to 16 (p&lt;0.0001) was seen after one cycle. Interestingly, TNBC pts seemed to have a greater decrease from 23.5 to 13 after one cycle. TM was well tolerated with grade 3/4 toxicities including: reversible neutropenia (2.3%), febrile neutropenia (0.04%), fatigue (0.2%). Five-year analysis showed a decrease in EPC's (p=0.004) and LOXL-2 (p&lt;0.001). At a median follow-up of 7.1 years, the EFS for 75 pts is 71.4%. The EFS for 36 pts with TNBC is 71.7%. EFS for stage 2/3 TNBC is 83% and for stage IV TNBC is 59.3%.

Conclusions: TM is safe, well tolerated and appears to affect multiple components of the tumor microenvironment that have been identified in pre-clinical models as important for progression. Ongoing studies in banked specimens are underway to further delineate its effect on copper dependent processes necessary for metastases. Randomized trials are warranted, especially in patients who are at high risk for relapse such as those with TNBC.

Citation Format: Sahota S, Willis A, Kornhauser N, Ward M, Cobham M, Cigler T, Moore A, Andreopoulou E, Fitzpatrick V, Schneider S, Prima N, Wiener A, Ko D, De Laurentiis A, Warren JD, Rubinchik A, Mittal V, Vahdat LT. A phase II study of copper-depletion using tetrathiomolybdate in patients with breast cancer at high risk for recurrence: Updated results [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-10-02.

Laparoscopic living donor nephrectomy: is there a difference between using a left or a right kidney?

BACKGROUND

The goal of this study was to review the results of 279 laparoscopic living donor nephrectomies (LLDN) regarding outcomes of using the left or the right kidney.

METHODS

Among 279 patients who underwent LLDN between August 1998 and April 2009, 260 underwent a left (group L) and 19, a right (group R) nephrectomy. The two groups were compared regarding intra- and postoperative parameters, including pre- and postoperative renal function, length of surgery, conversion to an open approach, delayed graft function, and complications.

RESULTS

There were no significant differences between the two groups regarding preoperative glomerular filtration rate (L = 129.5 ± 32 mL/min versus group R = 127.3 ± 26 mL/min), length of surgery (group L = 228 ± 58 minutes versus group R = 226 ± 62 minutes group), postoperative donor creatinine (group L = 1.36 ± 0.9 mg/dL versus group R = 1.48 ± 0.8 mg/dL), conversion to open (group L = 6.6% versus group R = 5.3%), delayed graft function (group L = 7.2% versus group R = 6.3%) and recipient postoperative creatinine at 1 month (group L = 1.54 ± 1.4 mg/dL versus group R = 1.32 ± 1.1 mg/dL). There were three intraoperative donor complications in group L (bleeding in one donor required transfusion), and none in group R. Similarly, there was a great albeit not a significant difference in the number of major postoperative donor complications among group L (n = 16) versus group R (n = 2). The right kidney was chosen because of the number of vessels (n = 5), presence of cysts (n = 5), size and renal function (n = 6), presence of renal stones (n = 2), and tortuous ureter (n = 1). The reasons for conversion to open included bleeding, anatomic issues, and presence of adhesions. It should be noted that during the last 3 years there were no conversions to open, whereas the only conversion among group R was the first case.

CONCLUSIONS

Intra- and postoperative parameters were comparable between the groups. Considering the limitations of the small sample size of right LLDNs in this study, it appears that it is as safe and effective as a left procedure. The learning curve is extremely important, as can be seen by the lack of conversion in the last 3 years.

Perampanel: expanding therapeutic options for patients with medically refractory secondary generalized convulsive seizures

To evaluate the efficacy of adjunctive, once-daily perampanel against secondarily generalized (SG) seizures in three Phase III trials (studies 304, 305, and 306) and their extension (study 307). The Phase III studies enrolled patients (≥ 12 years) with uncontrolled partial-onset seizures despite treatment with 1-3 concomitant antiepileptic drugs. Patients completing the core Phase III studies were eligible for the extension study. Endpoints included median percent change in SG seizure frequency, 50% responder (proportion of patients achieving a ≥ 50% reduction in SG seizure frequency), 75% response, and seizure-freedom rates. In total, 1480 patients were randomized and treated in the three perampanel Phase III trials. At baseline, 71.9% of placebo-treated and 68.4% of perampanel-treated patients had a history of SG seizures. In the individual core Phase III studies, perampanel (4-12 mg) reduced seizure frequency and improved responder rates. Consistent with this, in pooled analyses of the Phase III data, the median percent change in SG seizure frequency was -48.6%, -62.9%, and -53.3% with perampanel 4, 8, and 12 mg, respectively, vs -19.4% with placebo; 50% responder rates were 49.3%, 60.5%, and 53.7% vs 37.0% with placebo. More perampanel-treated patients had ≥ 75% reductions in SG seizure frequency, and seizure-freedom rates improved, compared with placebo. Improvements in seizure frequency and responder rate were maintained during the extension study. Perampanel consistently demonstrated efficacy against SG seizures when assessed using various endpoints. Furthermore, reductions in seizure frequency and improvements in responder rate were sustained with long-term perampanel treatment.

Detection of bursts and pauses in spike trains

Midbrain dopaminergic neurons in vivo exhibit a wide range of firing patterns. They normally fire constantly at a low rate, and speed up, firing a phasic burst when reward exceeds prediction, or pause when an expected reward does not occur. Therefore, the detection of bursts and pauses from spike train data is a critical problem when studying the role of phasic dopamine (DA) in reward related learning, and other DA dependent behaviors. However, few statistical methods have been developed that can identify bursts and pauses simultaneously. We propose a new statistical method, the Robust Gaussian Surprise (RGS) method, which performs an exhaustive search of bursts and pauses in spike trains simultaneously. We found that the RGS method is adaptable to various patterns of spike trains recorded in vivo, and is not influenced by baseline firing rate, making it applicable to all in vivo spike trains where baseline firing rates vary over time. We compare the performance of the RGS method to other methods of detecting bursts, such as the Poisson Surprise (PS), Rank Surprise (RS), and Template methods. Analysis of data using the RGS method reveals potential mechanisms underlying how bursts and pauses are controlled in DA neurons.

Extravaginal reservoirs of vaginal bacteria as risk factors for incident bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) represents shifts in microbiota from Lactobacillus spp. to diverse anaerobes. Although antibiotics relieve symptoms and temporarily eradicate BV-associated bacteria (BVAB), BV usually recurs. We investigated the role of extravaginal BVAB reservoirs in recurrence.

METHODS

Risks for BV acquisition over the course of 1 year were defined. DNA in vaginal, anal, and oral swab samples from enrollment was subjected to quantitative polymerase chain reaction assays targeting 16S ribosomal RNA genes of Gardnerella vaginalis, Lactobacillus crispatus, BVAB1, BVAB2, BVAB3, Megasphaera spp., Lactobacillus jensenii, and Leptotrichia/Sneathia spp. A case-control approach analyzed BVAB detection at enrollment for case patients (BV acquisition) versus controls (none).

RESULTS

Of 239 women enrolled without BV, 199 were seen in follow-up, and 40 experienced BV; 15 had all samples for analysis. Detection of G. vaginalis in oral cavity or anal samples and Leptotrichia/Sneathia spp. in anal samples was more common at enrollment among case patients, who also had higher concentrations of these bacteria and Megasphaera relative to 30 controls at each site. In contrast, L. crispatus was detected more frequently in anal samples among controls.

CONCLUSIONS

Women who acquire BV are more likely have previous colonization of extravaginal reservoirs with some BVAB, and less likely to have L. crispatus, suggesting that BVAB may be acquired vaginally from extravaginal reservoirs.

Evaluating the antipsychotic profile of the preferential PDE10A inhibitor, papaverine

RATIONALE

Prepulse inhibition (PPI) is an operational measure of sensorimotor gating that is deficient in schizophrenia patients. In rats, PPI deficits induced by dopamine (DA) agonists are reversed by antipsychotics. Inhibition of the striatum-rich phosphodiesterase (PDE)10A may represent a novel antipsychotic mechanism. Previous studies were controversial, showing antipsychotic-like profiles in measures of PPI for the preferential PDE10A inhibitor papaverine (PAP) but not the novel PDE10A inhibitor TP-10.

OBJECTIVE

The aim of the study was to evaluate the antipsychotic profile of PAP in rats using PPI.

MATERIALS AND METHODS

PPI deficits were induced in rats by apomorphine (APO; 0.1, 0.5 mg/kg) or D: -amphetamine (AMPH; 4 mg/kg). PAP (3, 10, 30 mg/kg) or haloperidol (HAL; 0.1 mg/kg) was tested against these agonists in Sprague-Dawley (SD) or Wistar (WI) rats. Prepulse intervals ranged from 10 to 120 ms. Further tests evaluated the effects of PAP on spontaneous locomotion, AMPH (1 mg/kg)-induced hyperlocomotion, and core body temperature (T degrees ).

RESULTS

HAL reversed APO-induced PPI deficits but PAP failed to reverse APO- and AMPH-induced PPI deficits at all doses, strains, pretreatment times, and prepulse intervals. PAP (30 mg/kg) significantly reduced AMPH hyperlocomotion in SD rats, and a similar pattern was detected in WI rats. This PAP dose also strongly reduced spontaneous locomotion and T degrees in SD rats.

CONCLUSION

Our study does not support an antipsychotic-like profile of PAP in dopaminergic PPI models.

Persistence of restricted CD4 T cell expansions in SIV-infected macaques resistant to SHIV89.6P superinfection

Attempts to evaluate the protective effect of live attenuated SIV vaccine strains have yielded variable results depending on the route of immunization, the level of attenuation, the level of divergence between the vaccine candidate and the challenge. The protective mechanisms induced by these vaccines are still not well understood. In an effort to address whether the diversity of the CD4+ T cell repertoire in cynomolgus macaques plays a role in the immunological protection following SIVmacC8 infection, we have performed a longitudinal follow-up of the CD4 repertoire by heteroduplex tracking assay in macaques mock-infected or infected with either the attenuated SIVmacC8 or its homologous SIVmacJ5 and challenged with simian-human immunodeficiency virus (SHIV89.6P). Viral load and CD4 absolute counts were determined in these animals and the presence of SHIV89.6P virus in challenged animals was evaluated by PCR and serology. In all macaques that were protected against the challenging virus, we demonstrated a reduced diversity in the CD4+ TRBV repertoire and a few dominant CD4+ T cell clones during early primary infection. In contrast, CD4 TRBV repertoire in unprotected macaques remained highly diverse. Moreover, some of the CD4 T cell clones that were expanded during primary SIV infection re-emerged after challenge suggesting their role in protection against the challenging virus. These results underline the importance of maintaining the CD4 T cell repertoire developed during acute infection and point to the restriction of the CD4 response to the vaccine as a correlate of protection.

Comparison of the E3 and L3 regions for arming oncolytic adenoviruses to achieve a high level of tumor-specific transgene expression

Arming oncolytic adenoviral vectors with anticancer transgenes that can be expressed in a tumor-selective manner may enable the engineering of vectors with increased potency, while retaining their safety profile. Armed oncolytic adenoviral vectors were constructed in which transgene expression has been linked via modified splice acceptor sequences that did not necessitate the deletion of any part of the adenoviral genome. Several oncolytic adenoviral vectors were compared in which the transgene was inserted in place of either the E3 or the L3 region. While all vectors had similar viral growth and cytotoxicity characteristics, the highest level of transgene expression was observed from a vector in which the transgene had been inserted downstream of the L3 23K protease gene, the Ad-23K-GM vector. Notably, no transgene expression occurred with this vector in the absence of DNA replication either in vitro or in vivo. In contrast, viruses in which the transgene was inserted into E3 locations exhibited a low level of transgene expression even in the absence of DNA replication. In summary, by utilizing the L3 region for arming oncolytic viruses, higher levels of tumor-specific transgene expression can be obtained without the need to delete any parts of the viral genome.

The kidney transplant program at the Massachusetts general hospital

Between February 1963 and December 2000, 1,627 kidney transplants were performed at the Massachusetts General Hospital. The majority (62%) were from cadaveric donors, although in recent years (1996-2000) 52% have been allografts from living donors, with an increase in living unrelated donors. The introduction of CsA and OKT3 in 1984 was associated with a significant improvement in actuarial renal allograft survival, although a persistent late attrition of allografts continues beyond the first year after transplantation. As reported in other centers, current actuarial survival for living unrelated allografts is superior to that of cadaveric allografts, and is quite similar to that observed in recipients of non-HLA identical living-related transplants. Our preliminary laparoscopic donor nephrectomy experience is encouraging as excellent allograft survival and function has been observed, with minimal morbidity associated with the procedure and a low rate of conversion to open nephrectomy. Recent changes in immunosuppressive protocols have resulted in lower early acute rejection rates, however the incidence of delayed graft function remains unchanged in cadaveric renal transplantation. The role of humoral immunity in allograft rejection has been progressively clarified and new approaches to control donor specific alloantibody production have been shown to be effective. Current clinical studies are ongoing to determine the optimal type and dose of calcineurin inhibitors beyond the first year after transplantation and to study whether avoidance of steroids is safe and feasible. Finally, an innovative tolerance induction protocol using the mixed chimerism approach has been successfully accomplished in selected patients with end-stage renal disease secondary to multiple myeloma. These encouraging observations emphasize that major changes from current immunosuppressive regimens are likely to occur over the next few years as more approaches to tolerance induction are explored clinically.

Conversion of oxacillin-resistant staphylococci from heterotypic to homotypic resistance expression

Staphylococci that acquire the mecA gene are usually resistant to beta-lactam antibiotics (methicillin or oxacillin resistance). mecA encodes a penicillin-binding protein (PBP 2a) that has a reduced affinity for beta-lactams. In some isolates with methicillin or oxacillin resistance, only a small proportion (< or =0.1%) of the population expresses resistance to > or =10 microg of oxacillin per ml (heterotypic resistance [HeR]), while in other isolates most of the population expresses resistance (homotypic resistance [HoR]). In the present study, growth of Staphylococcus aureus or Staphylococcus epidermidis strains with HeR in concentrations of oxacillin (0.3 to 0.7 microg/ml) that produced a fall or a lag in optical density converted the strains from the HeR to the HoR phenotype. The conversion from the HeR to the HoR phenotype appeared to be due to the selection of a highly resistant mutant population, as determined by fluctuation analysis and the failure of populations with HoR to revert to HeR after 60 generations of growth in antibiotic-free media. The frequencies of conversion were as high as 10(-3) to 10(-2). Conversion to HoR required an intact mecA gene and an increase in the level of mecA transcription since no highly resistant subpopulation could be selected after growth in oxacillin when mecA transcription was constitutively repressed or when mecA had been inactivated. In addition, in both S. epidermidis and S. aureus the level of resistance to vancomycin, which also acts directly on the staphylococcal cell wall, was greater among convertants with HoR than their isogenic parents. The conversion of a population from HeR to HoR involves the selection of a mutation(s) that occurs at a high frequency and most likely requires abundant PBP 2a.

A novel human cancer culture model for the study of prostate cancer

Research into molecular and genetic mechanisms underlying prostate carcinogenesis would be greatly advanced by in vitro models of prostate tumors representing primary tumors. We have successfully established an immortalized human prostate epithelial (HPE) cell culture derived from a primary tumor with telomerase. The actively proliferating early passaged RC-58T cells were transduced through infection with a retrovirus vector expressing the human telomerase catalytic subunit (hTERT). A high level of telomerase was detected in RC-58T/hTERT cells but not RC-58T cells. RC-58T/hTERT cells are currently growing well at passage 50, whereas RC-58T cells senesced at passage 7. RC-58T/hTERT cells exhibit transformed morphology. More importantly, these immortalized cells showed anchorage-independent growth as they formed colonies in soft agar and grew above the agar layer. Expression of androgen-regulated prostate specific gene NKX3.1 and epithelial specific cytokeratin 8 (CK8) but not prostate specific antigen (PSA) and androgen receptor was detected in RC-58T/hTERT cells. Prostate stem cell antigen (PSCA) and p16 were also expressed in this cell line. RC-58T/hTERT cells showed growth inhibition when exposed to retinoic acid and transforming growth factor (TGF)-beta1 known potent inhibitors of prostate epithelial cell growth. A number of chromosome alterations were observed including the loss of chromosomes Y, 3p, 10p, 17p, 18q and the gain of chromosomes 16 and 20. These results demonstrate that this primary tumor-derived HPE cell line retained its transformed phenotypes and should allow studies to elucidate molecular and genetic alterations involved in prostate cancer. This is the first documented case of an established human prostate cancer cell line from a primary tumor of a prostate cancer patient with telomerase.

Occupational allergic contact dermatitis in Singapore

Singapore has a resident population of 3,000,000 and a workforce of 1,780,000. Most are employed in manufacturing, services and commerce (245,000). From 1996 to 1998, 3472 cases were notified to the Ministry of Manpower and confirmed as occupational diseases. Noise-induced hearing loss accounted for 82% of cases, while only 11% of cases were industrial dermatitis. Occupational allergic contact dermatitis was not common, comprising approximately one third of the 369 cases of industrial dermatitis that were notified. However, we believe that the majority of cases are not notified to the authorities. The main occupational contact allergens were chromates, nickel, rubber chemicals, cutting fluids and resins. Most affected workers were from the construction, electronics and metalworking industries. Case series of occupational dermatoses among electronics and metal workers have been published. Of the cases of occupational dermatoses among electronics workers seen at a tertiary dermatological centre, 41% of 149 had allergic contact dermatitis (ACD). The commonest allergens were nickel, resins and rubber chemicals. In another case series of 252 metalworkers seen at the same dermatological centre, 23% suffered from ACD. The common allergens were metals and cutting fluids. Besides the common causes of ACD, unusual allergens have also been described. One example is ACD to grasses, which is seen mainly among military personnel. Population studies have been conducted in several industries. A survey of 2567 electronics workers revealed a 2% point prevalence of ACD. Of the occupationally relevant cases, 46 were nickel sensitive, 7 reacted to colophony, and 1 case to epoxy resin. A study of 272 prefabrication construction workers showed a 14% prevalence rate of occupational dermatitis. Of the 38 cases, 42% were ACD to chromates and rubber chemicals. Occupational ACD in Singapore is not as uncommon as the reported statistics suggest. Population-based reports, which overcome the problem of under-notification, show that the prevalence is variable in different industries.