Knowledge, Attitudes, and Perceptions of Skin Cancer Clinical Trials in the Hispanic Population

OBJECTIVE

To determine the factors that might limit Hispanic patients from participating in dermatological clinical trials.

METHODS

From January 2022 to July 2022, we administered a 31-item, in-person questionnaire to patients recruited in the waiting area of the Caridad Center, one of the largest free clinics in the United States with a predominately Hispanic population, and a nearby private primary care clinic.

RESULTS

Overall, Hispanic patients agreed significantly more with statements in the domain of attitude and behavioral beliefs compared to non-Hispanic survey respondents. The Hispanic ethnicity was associated with increased odds of agreeing with the following statements: "My community would really benefit from skin cancer clinical trials" (OR=0.52; 95% CI 0.30, 0.92), "My participation in a skin cancer study would be very good" (OR=0.59; 95% CI 0.35, 0.99), and "I like to do good for others" (OR=0.41; 95% CI 0.22, 0.77).

CONCLUSION

While the United States population is composed of 18.5% Hispanics, they only account for 1% of patients enrolled in clinical trials. This study helps identify potential motivational factors for Hispanic patients to participate in skin cancer clinical trials.

Experience in colorectal surgery at a quaternary care hospital in Bogotá, Colombia

INTRODUCTION AND AIMS

Colorectal cancer is among the three most common cancers worldwide. Knowledge and identification of suboptimal outcome-associated factors enable comprehensive patient management. The aim of the present study was to present the results of the surgical management of colorectal cancer at a quaternary care university hospital.

MATERIALS AND METHODS

An observational, analytic, cross-sectional study was conducted. Information was collected on a retrospective cohort of patients diagnosed with colorectal cancer from 2013 to 2017 at the Hospital Universitario Mayor Méderi, Bogotá, Colombia.

RESULTS

Data on 452 patients, within the study period, were collected. A total of 48.5% of the patients were men, the overall complication rate was 24%, the surgical site infection (SSI) rate was 15.38%, anastomotic dehiscence occurred in 4.18% of the patients, bleeding required reoperation in 1.32%, and the intrahospital mortality rate was 7.47%.

CONCLUSION

Colorectal cancer management at a university hospital was as beneficial as that provided by other types of hospitals, showing a direct association with complete R0 dissections; low complication rates, according to international reports; and reduced overall morbidity.

Risk factors for SARS-CoV-2 seropositivity in a health care worker population during the early pandemic

BACKGROUND

While others have reported severe acute respiratory syndrome-related coronavirus 2(SARS-CoV-2) seroprevalence studies in health care workers (HCWs), we leverage the use of a highly sensitive coronavirus antigen microarray to identify a group of seropositive health care workers who were missed by daily symptom screening that was instituted prior to any epidemiologically significant local outbreak. Given that most health care facilities rely on daily symptom screening as the primary method to identify SARS-CoV-2 among health care workers, here, we aim to determine how demographic, occupational, and clinical variables influence SARS-CoV-2 seropositivity among health care workers.

METHODS

We designed a cross-sectional survey of HCWs for SARS-CoV-2 seropositivity conducted from May 15th to June 30th 2020 at a 418-bed academic hospital in Orange County, California. From an eligible population of 5,349 HCWs, study participants were recruited in two ways: an open cohort, and a targeted cohort. The open cohort was open to anyone, whereas the targeted cohort that recruited HCWs previously screened for COVID-19 or work in high-risk units. A total of 1,557 HCWs completed the survey and provided specimens, including 1,044 in the open cohort and 513 in the targeted cohort. Demographic, occupational, and clinical variables were surveyed electronically. SARS-CoV-2 seropositivity was assessed using a coronavirus antigen microarray (CoVAM), which measures antibodies against eleven viral antigens to identify prior infection with 98% specificity and 93% sensitivity.

RESULTS

Among tested HCWs (n = 1,557), SARS-CoV-2 seropositivity was 10.8%, and risk factors included male gender (OR 1.48, 95% CI 1.05-2.06), exposure to COVID-19 outside of work (2.29, 1.14-4.29), working in food or environmental services (4.85, 1.51-14.85), and working in COVID-19 units (ICU: 2.28, 1.29-3.96; ward: 1.59, 1.01-2.48). Amongst 1,103 HCWs not previously screened, seropositivity was 8.0%, and additional risk factors included younger age (1.57, 1.00-2.45) and working in administration (2.69, 1.10-7.10).

CONCLUSION

SARS-CoV-2 seropositivity is significantly higher than reported case counts even among HCWs who are meticulously screened. Seropositive HCWs missed by screening were more likely to be younger, work outside direct patient care, or have exposure outside of work.

The role of defects in the persistent photoconductivity of BaSnO3thin films

Time-dependent photoconductivity (PC) and PC spectra have been studied in oxygen deficient BaSnO₃thin films grown on different substrates. X-ray spectroscopy measurements show that the films have epitaxially grown on MgO and SrTiO₃substrates. While on MgO the films are nearly unstrained, on SrTiO₃the resulting film is compressive strained in the plane. Electrical conductivity in dark is increased in one order of magnitude for the films on SrTiO₃in comparison to the one on MgO. This leads to an increase of PC in the latter film in at least one order of magnitude. PC spectra show a direct gap with a value ofEG=3.9eV for the film grown on MgO while on SrTiO₃EG=3.36eV. For both type of films, time-dependent PC curves show a persistent behavior after illumination is removed. These curves have been fitted employing an analytical procedure based on the frame of PC as a transmission phenomenon showing the relevant role of donor and acceptor defects as carrier traps and as a source of carriers. This model also suggests that in the BaSnO₃film on SrTiO₃more defects are created probably due to strain. This latter effect can also explain the different transition values obtained for both type of films.

Comparing outcomes of cholecystectomies in white vs. minority patients

BACKGROUND

This study aimed to investigate the disparity between white and minority patients undergoing cholecystectomies, including presentation, outcomes, and financial burden.

METHODS

This was an IRB approved retrospective review of all cholecystectomies at an academic medical center from 2013 to 2018. Data collected include demographics, insurance type, charge of admission, and clinical outcomes.

RESULTS

1539 patients underwent cholecystectomies. Of those, 36.9% were white and 63.1% were minority. Minority patients presented at a younger age than white patients (45.5 vs 53.9, p < 0.01) and required emergent admission (76.2% vs 68.4%, p < 0.01). No significant difference was found for clinical outcomes between white and minority. Minority patients were more commonly uninsured (32.1%). Among the uninsured, self-pay had a higher charge than emergency MediCal (by 5.46 per 1000 dollars).

CONCLUSION

Minority patients are more commonly disadvantaged at presentation and charged more due to insurance status despite similar outcomes after cholecystectomies.

O-077 The chromosomal constitution of embryos developing from 0PN zygotes

Study question

To compare the ploidy status of embryos originated from zygotes with absence of pronuclei (0PN) with those developing from normal two pronuclei (2PN) fertilization.

Summary answer

We did not find significant differences in euploidy rates between blastocysts from 0PN and 2PN zygotes.

What is known already

Information regarding the ploidy number of 0PN zygotes, even when the pronuclei number is assessed by time-lapse microscope coupled incubators, is still insufficient. Because of this, embryos originating from 0PN zygotes are usually discarded or individualized in order not to include them in first transfers. Even more, abnormal fertilization is considered as a proxy of poor embryo quality.

Study design, size, duration

A retrospective observational study from March 2016 and December 2021 including 80 PGT-A cycles in which at least one of the blastocysts studied developed from oocytes in which pronuclei were not seen at the time of fertilization check.

Participants/materials, setting, methods

307 blastocysts were studied, of which 115 originated from 0PN and 192 from 2PN zygotes. Pronuclear number was assessed 16-20 h after insemination. Zygotes with 0PN were cultured separately from 2PN ones of the same cohort. After extended culture, a biopsy was performed and the material obtained was genetically studied using Next Generation Sequencing. Statistical comparisons were made with Fisher's exact and Chi-square tests. Significance level was set at P&lt;0.05.

Main results and the role of chance

No differences were observed in euploidy rates between the 2PN and 0PN groups [55.2% (106/193) VS 43.5% (50/115)]. In aneuploid embryos originating from 2PN zygotes, a similar amount of trisomies and monosomies was observed (56 and 56 respectively). In contrast, aneuploid embryos from 0PN oocytes showed a greater number of trisomies than monosomies (55 and 35 respectively, P &lt; 0.05). None of the blastocysts resulting from 0PN was haploid, that is, we did not find parthenogenic embryos. Blastocysts derived from 0PN zygotes showed similar quality scoring than those from 2PN ones. To date, 20 euploid blastocysts from the 0PN group have been transferred, producing 12 pregnancies: 6 still ongoing and 4 healthy live births.

Limitations, reasons for caution

Non-visualization of pronuclei in oocytes that later generate normal diploid blastocysts may be due to a faster or slower cell cycle progression. Modifications in the daily fertilization check schedules of busy laboratories should also be considered.

Wider implications of the findings

Contrary to expectations, aneuploid embryos from 0PN oocytes showed a greater number of trisomies than monosomies. A significant fraction of the embryos generated from 0PN zygotes were actually diploid, with similar quality and outcome results than 2PN ones. This makes them perfectly usable in IVF routines.

Trial registration number

Not applicable

P-223 Women aged 40 or older and non-male factor have the same reproductive outcome using intracytoplasmic sperm injection (ICSI) or conventional in vitro fertilization (cIVF)

Study question

Do women aged 40 or older have the same reproductive outcome using ICSI or cIVF when male factor infertility is not present?

Summary answer

Women aged 40 or older with non-male factor partners achieved similar reproductive outcomes either with ICSI or cIVF.

What is known already

Although initially proposed to treat couples with severe male factor infertility, ICSI has become the preferred tool to treat patient populations others than initially intended. Many studies and international forums, however, have alerted that its overuse is not free due to its safety, cost and time-consuming concerns. Moreover, it was noted that it does not increase clinical outcomes even in cases of compromised oocyte factor such as poor responder patients or few oocytes retrieved. However, there is still no information regarding its use in the group of patients of advanced reproductive age.

Study design, size, duration

Retrospective cohort study including 412 women aged 40 or older with non-male factor infertility performing ICSI or cIVF between May 2015 and October 2017.

Participants/materials, setting, methods

Patients underwent ICSI (n = 109) or cIVF (n = 303) according to medical indication. The decision to use ICSI in non-male factor patients was merely operational, with the objective of evaluating oocyte maturity.Those cycles with own oocytes, non-male factor and fresh embryo transfers were included. Semen samples were considered normal following the World Health Organization fifth edition sperm parameters values, and prepared by density gradient selection.

Main results and the role of chance

The primary outcome was clinical pregnancy rate. Secondary outcomes included ongoing pregnancy, miscarriage and implantation rates. Statistical significance was denoted by P &lt; 0.05. The mean age of the women were 41.4 in the ICSI group and 41.6 years in the cIVF group, while the mean age for male couple was 43.6 and 41.6 respectively.

No differences between ICSI and cIVF groups were observed regarding clinical pregnancy [16.5% (18/109) vs. 20.8% (63/303)], ongoing pregnancy [9.2% (10/109) vs. 7.9% (24/303)], miscarriage [41.2% (7/17) vs. 46,5% (20/43)], and implantation rates [11.3% (17/151) vs. 9.9% (50/506)].

Limitations, reasons for caution

These results need confirmation with a bigger population size. As with any retrospective study, the potential for residual confounding exists.

Wider implications of the findings

These data suggest that ICSI offers no clinical benefit for women aged 40 and older with non-male factor infertility, beyond oocyte maturation classification.

Trial registration number

not applicable

Persistence of SARS-CoV-2 Antibodies in Vaccinated Health Care Workers Analyzed by Coronavirus Antigen Microarray

Recent studies provide conflicting evidence on the persistence of SARS-CoV-2 immunity induced by mRNA vaccines. Here, we aim to quantify the persistence of humoral immunity following vaccination using a coronavirus antigen microarray that includes 10 SARS-CoV-2 antigens. In a prospective longitudinal cohort of 240 healthcare workers, composite SARS-CoV-2 IgG antibody levels did not wane significantly over a 6-month study period. In the subset of the study population previously exposed to SARS-CoV-2 based on seropositivity for nucleocapsid antibodies, higher composite anti-spike IgG levels were measured before the vaccine but no significant difference from unexposed individuals was observed at 6 months. Age, vaccine type, or worker role did not significantly impact composite IgG levels, although non-significant trends towards lower antibody levels in older participants and higher antibody levels with Moderna vaccine were observed at 6 months. A small subset of our cohort were classified as having waning antibody titers at 6 months, and these individuals were less likely to work in patient care roles and more likely to have prior exposure to SARS-CoV-2.

Infection prevention strategies are highly protective in COVID-19 units while main risks to healthcare professionals come from coworkers and the community

Background

Early evaluations of healthcare professional (HCP) COVID-19 risk occurred during insufficient personal protective equipment and disproportionate testing, contributing to perceptions of high patient-care related HCP risk. We evaluated HCP COVID-19 seropositivity after accounting for community factors and coworker outbreaks.

Methods

Prior to universal masking, we conducted a single-center retrospective cohort plus cross-sectional study. All HCP (1) seen by Occupational Health for COVID-like symptoms (regardless of test result) or assigned to (2) dedicated COVID-19 units, (3) units with a COVID-19 HCP outbreak, or (4) control units from 01/01/2020 to 04/15/2020 were offered serologic testing by an FDA-authorized assay plus a research assay against 67 respiratory viruses, including 11 SARS-CoV-2 antigens. Multivariable models assessed the association of demographics, job role, comorbidities, care of a COVID-19 patient, and geocoded socioeconomic status with positive serology.

Results

Of 654 participants, 87 (13.3%) were seropositive; among these 60.8% (N = 52) had never cared for a COVID-19 patient. Being male (OR 1.79, CI 1.05–3.04, p = 0.03), working in a unit with a HCP-outbreak unit (OR 2.21, CI 1.28–3.81, p < 0.01), living in a community with low owner-occupied housing (OR = 1.63, CI = 1.00–2.64, p = 0.05), and ethnically Latino (OR 2.10, CI 1.12–3.96, p = 0.02) were positively-associated with COVID-19 seropositivity, while working in dedicated COVID-19 units was negatively-associated (OR 0.53, CI = 0.30–0.94, p = 0.03). The research assay identified 25 additional seropositive individuals (78 [12%] vs. 53 [8%], p < 0.01).

Conclusions

Prior to universal masking, HCP COVID-19 risk was dominated by workplace and community exposures while working in a dedicated COVID-19 unit was protective, suggesting that infection prevention protocols prevent patient-to-HCP transmission.

Article summary

Prior to universal masking, HCP COVID-19 risk was dominated by workplace and community exposures while working in a dedicated COVID-19 unit was protective, suggesting that infection prevention protocols prevent patient-to-HCP transmission.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-01031-5.

Morphine exposure alters Fos expression in a sex-, age-, and brain region-specific manner during adolescence

Data in both humans and preclinical animal models clearly indicate drug exposure during adolescence, when the "reward" circuitry of the brain develops, increases the risk of substance use and other mental health disorders later in life. Human data indicate that different neural and behavioral sequelae can be observed in early versus late adolescence. However, most studies with rodent models examine a single adolescent age compared to a mature adult age, and often only in males. Herein, we sought to determine whether the acute response to the opioid morphine would also differ across adolescence, and by sex. By quantifying Fos positive cells, a proxy for neural activity, at different stages during adolescence (pre-, early, mid-, and late adolescence) and in multiple reward regions (prefrontal cortex, nucleus accumbens, caudate/putamen), we determined that the neural response to acute morphine is highly dependent on adolescent age, sex, and brain region. These data suggest that heterogeneity in the consequences of adolescent opioid exposure may be due to age- and sex-specific developmental profiles in individual reward processing regions. In future studies, it will be important to add age within adolescence as an independent variable for a holistic view of healthy or abnormal reward-related neural development.

Investigating a Substance Abuse Screening in a Trauma Setting

INTRODUCTION

Drug and alcohol consumption are often associated with trauma-related injuries. Various studies have been conducted which have shown the benefits of screening and brief intervention (SBI) tools for alcohol consumption. Despite their success, there are few SBI tools utilized for substance use and minimal reports of computerized versions. We hypothesized that a computerized SBI tool for drug use would be effective at identifying patients at risk of substance abuse in a trauma setting.

METHODS

This was a prospective evaluation of a computerized alcohol and drug screening and brief intervention survey derived from the National Institute on Drug Abuse. The survey was given to all eligible trauma patients at UCI's Level 1 trauma facility between February 2019 and March 2020. Based on self-reported answers, a substance involvement (SI) score was generated which classified a patient's drug abuse risk as none (0), low (1-3), moderate (4-26), or high (27+). Statistical tests were then used to examine associations between demographic variables and risk categorization.

RESULTS

A total of 1801 patients completed the entire survey. Of those, 346 (19.3%) patients reported use of illicit drugs: 10 for non-medical prescription use (.6%), 308 (17.1%) for non-prescription drug use, and 28 (1.6%) for both. Secondary analysis revealed a greater number of males were eligible for further SI assessment (25.1% vs 11.0%, P < .001). Of those, a greater proportion of men were classified as moderate/high risk (81.6% vs 61.5%, P < .001). Further breakdown revealed a greater proportion of patients ≤25 years old reported use of drugs compared to >85 years old (37.0% vs .5%, P < .001). In contrast to the self-reported data, there was an overall positive rate of toxicology of 48.51%.

CONCLUSION

The analysis shows that the electronic survey identifies patients at risk of drug abuse, allowing for real-time intervention. Furthermore, it is granular enough to specify at-risk groups. However, a lower self-reported rate, as expected, was elucidated. Further studies to evaluate for improved screening and targeted intervention are warranted.

Increased Mortality in Underinsured Penetrating Trauma Patients

INTRODUCTION

It remains unclear whether an increased mortality risk in uninsured patients exists across Injury Severity Score (ISS) classifications. We hypothesized that penetrating trauma self-pay patients would have a similarly increased mortality risk across all ISS categories.

METHODS

The National Trauma Data Bank (2013-2015) was queried for patients presenting with penetrating firearm, explosive, or stab wound injuries. 115 651 patients were identified and a stratified multivariable logistic regression model was used.

RESULTS

In the >15 ISS group, self-pay patients had a lower median total hospital Length of Stay (LOS) (3 vs 8, P < .001), lower median Intensive Care Unit LOS (1 vs 3, P < .001), and lower median ventilator days (0 vs 1, P < .001). Self-pay patients had an increased risk for mortality compared to patients with private insurance in both the ≤15 ISS group (OR 2.68, P < .001) and >15 ISS group (OR 1.56, P < .001).

CONCLUSION

Uninsured patients have an increased mortality risk in both low and high ISS groups. A higher mortality risk among uninsured patients in the high ISS group can be explained by decreased resource availability and lower ICU days and ventilator time. However, more studies are needed to determine why there is an even greater mortality risk among uninsured patients with mild ISS.

Non-Selective Thoracic Computed Tomography in Trauma Patients Results in Injury Severity Score Inflation

INTRODUCTION

Extensive research relying on Injury Severity Scores (ISS) reports a mortality benefit from routine non-selective thoracic CTs (an integral part of pan-computed tomography (pan-CT)s). Recent research suggests this mortality benefit may be artifact. We hypothesized that the use of pan-CTs inflates ISS categorization in patients, artificially affecting admission rates and apparent mortality benefit.

METHODS

Eight hundred and eleven patients were identified with an ISS >15 with significant findings in the chest area. Patient charts were reviewed and scores were adjusted to exclude only occult injuries that did not affect treatment plan. Pearson chi-square tests and multivariable logistic regression were used to compare adjusted cases vs non-adjusted cases.

RESULTS

After adjusting for inflation, 388 (47.8%) patients remained in the same ISS category, 378 (46.6%) were reclassified into 1 lower ISS category, and 45 (5.6%) patients were reclassified into 2 lower ISS categories. Patients reclassified by 1 category had a lower rate of mortality (P < 0.001), lower median total hospital LOS (P < .001), ICU days (P < .001), and ventilator days (P = 0.008), compared to those that remained in the same ISS category.

CONCLUSION

Injury Severity Score inflation artificially increases survival rate, perpetuating the increased use of pan-CTs. This artifact has been propagated by outdated mortality prediction calculation methods. Thus, prospective evaluations of algorithms for more selective CT scanning are warranted.

Regional, Racial, and Mortality Disparities Associated With Neurosurgeon Staffing at Level I Trauma Centers

BACKGROUND

Traumatic brain injury (TBI) occurs in approximately 30% of trauma patients. Because neurosurgeons hold expertise in treating TBI, increased neurosurgical staffing may improve patient outcomes. We hypothesized that TBI patients treated at level I trauma centers (L1TCs) with ≥3 neurosurgeons have a decreased risk of mortality vs. those treated at L1TCs with <3 neurosurgeons.

METHODS

The Trauma Quality Improvement Program database (2010-2016) was queried for patients ≥18 years with TBI. Patient characteristics and mortality were compared between ≥3 and <3 neurosurgeon-staffed L1TCs. A multivariable logistic regression analysis was used to identify risk factors associated with mortality.

RESULTS

Traumatic brain injury occurred in 243 438 patients with 5188 (2%) presenting to L1TCs with <3 neurosurgeons and 238 250 (98%) to L1TCs with ≥3 neurosurgeons. Median injury severity score (ISS) was similar between both groups (17, P = .09). There were more Black (37% vs. 12%, P < .001) and Hispanic (18% vs. 12%, P < .001) patients in the <3 neurosurgeon group. Nearly 60% of L1TCs with <3 neurosurgeons are found in the South. Mortality was higher in the <3 vs. the ≥3 group (12% vs. 10%, P < .001). Patients treated in the <3 neurosurgeon group had a higher risk for mortality than those treated in the ≥3 neurosurgeon group (odds ratio (OR) 1.13, 95% confidence intervals (CI) 1.01-1.26, P = .028).

DISCUSSION

There exists a significant racial disparity in access to neurosurgeon staffing with additional disparities in outcomes based on staffing. Future efforts are needed to improve this chasm of care that exists for trauma patients of color.

Diagnosis and Treatment of Chronic Medical Conditions Among Trauma Patients at a Level 1 Trauma Center

Diabetes mellitus (DM) and hypertension (HTN) are increasing in prevalence in the population. Level 1 trauma facilities are often faced with managing these chronic conditions. Recent studies indicated that 12-44% of patients presenting traumas are found to have incidental findings by imaging representing undiagnosed medical conditions, with 10% reported requiring further management [Surendran A, Mori A, Varma DK, Gruen RL. Systematic review of the benefits and harms of whole-body computed tomography in the early management of multitrauma patients: Are we getting the whole picture? J Trauma and Acute Care Surg. 2014;76(4):1122-1130]. Between 2015 and 2016, 852 patients seen at a level 1 trauma center were analyzed. Patients were evaluated who received a new diagnosis of HTN or DM, or had preexisting diagnosis of HTN or DM whose management was changed. Uncontrolled HTN or DM was defined as a need for either a change in medication or primary care optimization prior to discharge. Among the patients evaluated, 6.3% and 3.0% received new diagnoses of HTN and DM, respectively. Additionally, 34.4% and 35.3% of patients were found to have uncontrolled HTN and DM and required medical optimization, respectively. The high prevalence of undiagnosed or suboptimal management for chronic conditions indicates that more research is warranted for defining, screening for, and treating surgical patients with poorly controlled medical conditions with these comorbidities.

A semi-automated brain atlas-based analysis pipeline for c-Fos immunohistochemical data

BACKGROUND

The use of immunohistochemistry to quantify neural markers in various brain regions is a staple of neuroscience research. Numerous programs exist to automate quantification, but manual assignment of regions of interest (ROIs) within individual brain sections remains time consuming and can introduce interobserver variability.

NEW METHOD

We have developed a novel open source FIJI-based immunohistochemical data analysis pipeline, Atlas-Based Analysis (ABA). ABA uses landmark-based image warping to adjust the experimental image to closely align with a published rat brain atlas. c-Fos positive cells are then quantified within predetermined ROI coordinates derived from the brain atlas. Image warping adjusts for natural variation in brain sections to ensure reliable alignment of ROIs for data analysis. This pipeline can be adapted for new atlases, landmarks, ROIs, and quantification measurements.

RESULTS

ABA permits rapid quantification of immunoreactivity in multiple ROIs and produces results with high levels of interobserver consistency.

COMPARISON WITH EXISTING METHODS

Compared to manual ROI designation, ABA reduces total analysis time by ∼70%. With correct use of landmarks for image warping, ABA produces similar results to manually drawn ROIs, results in no interobserver variability, and maintains c-Fos+ pixel dimensions.

CONCLUSIONS

ABA reduces time to obtain reliable results when performing automated immunoreactivity quantification and allows multiple users to analyze data without compromising the reliability of data obtained.

Reconstitution of the gut microbiota of antibiotic-treated patients by autologous fecal microbiota transplant

Antibiotic treatment can deplete the commensal bacteria of a patient's gut microbiota and, paradoxically, increase their risk of subsequent infections. In allogeneic hematopoietic stem cell transplantation (allo-HSCT), antibiotic administration is essential for optimal clinical outcomes but significantly disrupts intestinal microbiota diversity, leading to loss of many beneficial microbes. Although gut microbiota diversity loss during allo-HSCT is associated with increased mortality, approaches to reestablish depleted commensal bacteria have yet to be developed. We have initiated a randomized, controlled clinical trial of autologous fecal microbiota transplantation (auto-FMT) versus no intervention and have analyzed the intestinal microbiota profiles of 25 allo-HSCT patients (14 who received auto-FMT treatment and 11 control patients who did not). Changes in gut microbiota diversity and composition revealed that the auto-FMT intervention boosted microbial diversity and reestablished the intestinal microbiota composition that the patient had before antibiotic treatment and allo-HSCT. These results demonstrate the potential for fecal sample banking and posttreatment remediation of a patient's gut microbiota after microbiota-depleting antibiotic treatment during allo-HSCT.

Marijuana use and outcomes in adult and pediatric trauma patients after legalization in California

BACKGROUND

Marijuana has become legal in eight states since 2012. We hypothesized the incidence of marijuana-positive trauma patients and rate of mortality has increased post-legalization.

METHODS

A single level-I trauma center was used to identify patients screening positive for marijuana on urine-toxicology. Patients in the pre-legalization and post-legalization periods were compared.

RESULTS

In the pre-legalization cohort 9.4% were marijuana-positive versus 11.0% in the post-legalization cohort (p = 0.001). Marijuana-positive patients post-legalization had higher rates of critical trauma activation (20.0% vs. 15.0%, p = 0.01) and mortality (2.6% vs. 1.2%, p = 0.03). In the pediatric (age 12-17) subgroup, the incidence of marijuana-positive patients did not change after legalization (pre: 39.3%, post: 46.4%, p = 0.24).

CONCLUSION

The incidence of marijuana-positive trauma patients increased post-legalization. Adult marijuana-positive trauma patients post-legalization were more likely to meet criteria for critical trauma activation and have a higher mortality rate. A subgroup of pediatric patients had an alarmingly high rate of marijuana use.

SUMMARY

The rate of marijuana use among trauma patients increased post-legalization in California. The rate of critical trauma activation also increased as well as the mortality rate.

eFAST for Pneumothorax: Real-Life Application in an Urban Level 1 Center by Trauma Team Members

The focused assessment with sonography for trauma (FAST) examination has become the standard of care for rapid evaluation of trauma patients. Extended FAST (eFAST) is the use of ultra-sonography for the detection of pneumothorax (PTX). The exact sensitivity and specificity of eFAST detecting traumatic PTX during practical “real-life” application is yet to be investigated. This is a retrospective review of all trauma patients with a diagnosis of PTX, who were treated at a large level 1 urban trauma center from March 2013 through July 2014. Charts were reviewed for results of imaging, which included eFAST, chest X-ray, and CT scan. The requirement of tube thoracostomy and mechanism of injury were also analyzed. A total of 369 patients with a diagnosis of PTX were identified. A total of 69 patients were excluded, as eFASTwas either not performed or not documented, leaving 300 patients identified with PTX. A total of 113 patients had clinically significant PTX (37.6%), requiring immediate tube thoracostomy placement. eFAST yielded a positive diagnosis of PTX in 19 patients (16.8%), and all were clinically significant, requiring tube thoracostomy. Chest X-ray detected clinically significant PTX in 105 patients (92.9%). The literature on the utility of eFAST for PTX in trauma is variable. Our data show that although specific for clinically significant traumatic PTX, it has poor sensitivity when performed by clinicians with variable levels of ultrasound training. We conclude that CT is still the gold standard in detecting PTX, and clinicians performing eFAST should have adequate training.

eFAST for Pneumothorax: Real-Life Application in an Urban Level 1 Center by Trauma Team Members

The focused assessment with sonography for trauma (FAST) examination has become the standard of care for rapid evaluation of trauma patients. Extended FAST (eFAST) is the use of ultrasonography for the detection of pneumothorax (PTX). The exact sensitivity and specificity of eFAST detecting traumatic PTX during practical "real-life" application is yet to be investigated. This is a retrospective review of all trauma patients with a diagnosis of PTX, who were treated at a large level 1 urban trauma center from March 2013 through July 2014. Charts were reviewed for results of imaging, which included eFAST, chest X-ray, and CT scan. The requirement of tube thoracostomy and mechanism of injury were also analyzed. A total of 369 patients with a diagnosis of PTX were identified. A total of 69 patients were excluded, as eFAST was either not performed or not documented, leaving 300 patients identified with PTX. A total of 113 patients had clinically significant PTX (37.6%), requiring immediate tube thoracostomy placement. eFAST yielded a positive diagnosis of PTX in 19 patients (16.8%), and all were clinically significant, requiring tube thoracostomy. Chest X-ray detected clinically significant PTX in 105 patients (92.9%). The literature on the utility of eFAST for PTX in trauma is variable. Our data show that although specific for clinically significant traumatic PTX, it has poor sensitivity when performed by clinicians with variable levels of ultrasound training. We conclude that CT is still the gold standard in detecting PTX, and clinicians performing eFAST should have adequate training.

Protective Factors in the Intestinal Microbiome Against Clostridium difficile Infection in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

Background

Clostridium difficile infection (CDI) is a frequent complication in recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT), who receive intensive treatments that significantly disrupt the intestinal microbiota. In this study, we examined the microbiota composition of allo-HSCT recipients to identify bacterial colonizers that confer protection against CDI after engraftment.

Methods

Feces collected from adult recipients allo-HSCT at engraftment were analyzed; 16S ribosomal RNA genes were sequenced and analyzed from each sample. Bacterial taxa with protective effects against development of CDI were identified by means of linear discriminant analysis effect size analysis and then further assessed with clinical predictors of CDI using survival analysis.

Results

A total of 234 allo-HSCT recipients were studied; postengraftment CDI developed in 53 (22.6%). Within the composition of the microbiota, the presence of 3 distinct bacterial taxa was correlated with protection against CDI: Bacteroidetes, Lachnospiraceae, and Ruminococcaceae. Colonization with these groups at engraftment was associated with a 60% lower risk of CDI, independent of clinical factors.

Conclusions

Colonization with these 3 bacterial groups is associated with a lower risk of CDI. These groups have been shown to be vital components of the intestinal microbiota. Targeted efforts to maintain them may help minimize the risk of CDI in this at-risk population.

Estimation of central aortic forces in the ballistocardiogram under rest and exercise conditions

The ballistocardiogram (BCG) signal represents the movements of the body in response to cardiac ejection of blood. The BCG signal can change considerably under various physiological states; however, little information exists in literature describing how these forces are generated. A physical analysis is presented using a finite element model of thoracic aortic vasculature to quantify forces generated by the blood flow during the cardiac cycle. The traction at the fluid-solid interface of this deformable wall model generates a Central Aortic Force (CAF) which appears of similar magnitude to recorded BCG forces. The increased pulse pressure in an exercise simulation caused a significant increase in CAF, which is consistent with recent BCG measurements in exercise recovery.

Evaluation and applications of optical cell density probes in mammalian cell bioreactors

On-line optical cell density probes were implemented to continuously monitor the cell densities in mammalian cell bioreactor and to achieve advanced bioreactor controls. We tested cell density probes from six manufacturers in high cell density bioreactors. When externally calibrated, Aquasant and Ingold backscattering probes produced the most linear probe responses (PR) versus cell density (CD), followed by the ASR and Cerex laser probes. Monitek and Wedgewood transmission probes had lower resolutions. All probes were tested in two murine hybridoma fermentations. Cell densities varied between 1 x 10(6) cells/mL to 20 x 10(6) cells/mL and the bioreactors were operated for 5 to 7 weeks. For our bioreactors, Aquasant, Ingold, ASR, Wedgewood, and Monitek probes gave satisfactory responses. Little fouling was observed with any probe at the end of 2 weeks. Fouling was a possibility after 3 weeks in one bioreactor but its effect can be easily corrected. Cell density control and specific perfusion control of bioreactors based on the Aquasant probe were achieved. Implementation of cell density probe based perfusion control, instead of "step perfusion adjustments" based on manual hemacytometer control, will result in smoother operation, healthier cultures, increased medium delivery efficiency, and reduced operational excursions.

Prenylated Rab acceptor protein is a receptor for prenylated small GTPases

Localization of Ras and Ras-like proteins to the correct subcellular compartment is essential for these proteins to mediate their biological effects. Many members of the Ras superfamily (Ha-Ras, N-Ras, TC21, and RhoA) are prenylated in the cytoplasm and then transit through the endomembrane system on their way to the plasma membrane. The proteins that aid in the trafficking of the small GTPases have not been well characterized. We report here that prenylated Rab acceptor protein (PRA1), which others previously identified as a prenylation-dependent receptor for Rab proteins, also interacts with Ha-Ras, RhoA, TC21, and Rap1a. The interaction of these small GTPases with PRA1 requires their post-translational modification by prenylation. The prenylation-dependent association of PRA1 with multiple GTPases is conserved in evolution; the yeast PRA1 protein associates with both Ha-Ras and RhoA. Earlier studies reported the presence of PRA1 in the Golgi, and we show here that PRA1 co-localizes with Ha-Ras and RhoA in the Golgi compartment. We suggest that PRA1 acts as an escort protein for small GTPases by binding to the hydrophobic isoprenoid moieties of the small GTPases and facilitates their trafficking through the endomembrane system.

Peroxisomal proteins in rat gametes

Peroxisomes are essential subcellular organelles, which appear to be derived from pre-existing organelles. This biogenetic mechanism assumes the presence of peroxisomes in either or both mammalian gametes (sperms and/or oocytes). In order to test the presence and subcellular localization of peroxisomal proteins in rat sperms and oocytes, the authors carried out fractionation and immunofluorescence experiments. The results showed that rat oocytes contain peroxisome-like structures, which were detected by indirect immunofluorescence, using an antisera against total peroxisomal proteins. In contrast, such structures were not detected in rat sperms, which appear to contain catalase localized in the cell cytosol. The results reported herein show evidence for the first time of the presence of peroxisome-like structures in mammalian oocytes, and provide evidence for the peroxisome biogenesis hypothesis, by division of pre-existing organelles.

[Clinical characterization of 450 patients with cerebrovascular disease admitted to a public hospital during 1997]

BACKGROUND

In Chile, cerebrovascular diseases are the fifth cause of death among men and the third cause among women.

AIM

To assess the clinical features and management of patients with cerebrovascular disease admitted to a public hospital during 1997.

PATIENTS AND METHODS

A retrospective analysis of clinical records of patients discharged with a diagnosis of cerebrovascular disease. Those records in which there was discordance between the discharge diagnosis and the clinical picture were not considered in the analysis.

RESULTS

Of the 563 discharges from the hospital with the diagnosis of cerebrovascular disease, 487 records were located and 450 were considered in the analysis. Fifty four percent of patients were male and ages ranged from 17 to 96 years old. Fifty-one percent of patients had an ischemic stroke, 34% a cerebral hemorrhage, 12% a subarachnoidal hemorrhage and 3% a transient ischemic attack. There was a history of hypertension in 64% patients and 20% had an adequate treatment. Eighteen percent were diabetics, 34% had a heart disease and 20% had a previous episode of stroke. Mean hospital stay was 6.3 days in the emergency room and 11 days in the neurology ward. Hospital infections appeared in 21% of patients (respiratory in 68% and urinary in 22%), lethality was 30.5% and a CAT scan was done in 94%. At the moment of admission, 10% of patients had an evolution of less than 2 hours, 27% had an evolution between 2 and 6 hours and nine cases were potential eligible for thrombolysis.

CONCLUSION

This is a picture of the local features of patients with cerebrovascular diseases that can be used as a reference for future studies.

Negative regulation of the serine/threonine kinase B-Raf by Akt

B-Raf contains multiple Akt consensus sites located within its amino-terminal regulatory domain. One site, Ser(364), is conserved with c-Raf but two additional sites, Ser(428) and Thr(439), are unique to B-Raf. We have investigated the role of both the conserved and unique phosphorylation sites in the regulation of B-Raf activity in vitro and in vivo. We show that phosphorylation of B-Raf by Akt occurs at multiple residues within its amino-terminal regulatory domain, at both the conserved and unique phosphorylation sites. The alteration of the serine residues within the Akt consensus sites to alanines results in a progressive increase in enzymatic activity in vitro and in vivo. Furthermore, expression of Akt inhibits epidermal growth factor-induced B-Raf activity and inhibition of Akt with LY294002 up-regulates B-Raf activity, suggesting that Akt negatively regulates B-Raf in vivo. Our results demonstrate that B-Raf activity can be negatively regulated by Akt through phosphorylation in the amino-terminal regulatory domain of B-Raf. This cross-talk between the B-Raf and Akt serine/threonine kinases is likely to play an important role in modulating the signaling specificity of the Ras/Raf pathway and in promoting biological outcome.

Allopurinol encapsulated in polycyanoacrylate nanoparticles as potential lysosomatropic carrier: preparation and trypanocidal activity

The activity of allopurinol-loaded polyethylcyanoacrylate nanoparticles against Trypanosoma cruzi was compared to that of free allopurinol using in vitro cultures of epimastigotes. Ethylcyanoacrylate nanoparticles were prepared by an emulsion polymerization process, and formulations containing different concentrations of allopurinol, polyethylcyanoacrylate and surfactants were investigated and analyzed in size and amount of drug entrapped. The nanoparticles obtained were less than 200 nm in size, as measured by electron microscopy and cytometry. The peak amount of allopurinol entrapped in the nanoparticles was 62.8+/-1.9 microg mg(-1) of nanoparticles using 400 microl of polyethylcyanoacrylate, 200 microl of surfactant (Tween 20) and 20 mg of allopurinol in 50 ml of polymerization medium and the association efficiency was 100.7%. After 6 h of incubation at pH 7.4 the release of allopurinol from the nanoparticles was 7.4%, while at pH 1.2 only 3.1% was released after 4-6 h (t=42.8, P<0.0001). The in vitro studies, using cultures of T. cruzi epimastigotes, demonstrated considerable increases in the trypanocidal activity of the allopurinol-loaded nanoparticles in comparison with a standard solution of allopurinol (91.5 vs. 45.9%) at an allopurinol concentration of 16.7 microg ml(-1). In addition, it was shown that the unloaded nanoparticles, by mechanisms not completely elucidated, had a trypanocidal activity similar to that of standard solutions of allopurinol. To study cytotoxicity, increasing concentrations of unloaded nanoparticles were incubated on vero-line cell cultures. The concentration that killed 50% cells was 200 microg ml(-1), four times higher than that necessary to kill 50% of T. cruzi. It is concluded that the polyethylcyanoacrylate nanoparticles constitute a good carrier of drugs against the T. cruzi. The allopurinol loaded-nanoparticles significantly increased the trypanocidal activity in comparison to the free drug.

The long-term reinfection rate and the course of duodenal ulcer disease after eradication of Helicobacter pylori in a developing country

OBJECTIVE

The aim of this study was to evaluate the effect of Helicobacter pylori (H. pylori) eradication on the natural history of duodenal ulcer disease and the reinfection rate after treatment in a developing country.

METHODS

A total of 111 H. pylori-infected patients with duodenal ulcer were treated with either omeprazole or famotidine plus two antibiotics for 2 wk. Those failed to respond to treatment were retreated with bismuth-based triple therapy.

RESULTS

The radication rate was 76% (95% CI: 67-83%). Eventually, H. pylori was eradicated in 96 of the 111 patients (86%), who were followed-up clinically and endoscopically for a mean of 37.2 months. The cumulative reinfection rate after eradication (Kaplan-Meier) was 8%+/-3% in yr 1, 11%+/-4% in yr 2, and 13%+/-4% in yr 3. Nine of the 12 reinfections occurred during yr 1. Recurrence of duodenal ulcer was detected in five patients (5.2%), all of them during yr 1 of follow-up. Histologically, gastritis scores (according to the Sydney system) improved significantly after eradication.

CONCLUSIONS

In a high prevalence setting, H. pylori eradication and early reinfection rates after treatment are similar to rates observed in a low prevalence environment, whereas the late reinfection rate seems to be higher. However, up to 3 yr after treatment, most treated patients are free of H. pylori infection and/or ulcer activity. Even longer follow-up studies are necessary to determine whether specific retreatment policies are necessary to maintain long term eradication in developing countries.

[Microbiological study of gallbladder bile in a high risk zone for gallbladder cancer]

BACKGROUND

Gallbladder cancer is frequent in Chile and there is sparse information about the association between this type of cancer and the presence of bacteria in the gallbladder bile.

AIM

To determine the presence of aerobic bacteria in gallbladder bile in patients with and without gallbladder cancer.

MATERIAL AND METHODS

A microbiological analysis of bile and pathological study was performed in 608 gallbladders, obtained during to cholecystectomies performed to 513 women and 95 men aged 44 years old as a mean.

RESULTS

Pathological study showed a chronic cholecystitis in 468 cases (77%), an acute cholecystitis in 140 (33%), cancer in 24 (3.9%) and dysplasia in 5 cases (0.8%). A positive culture was obtained in 22.5% of women and 28.5% of males. Twenty seven percent of women over 30 years old had positive cultures compared with 10% of younger women (p < 0.001). Thirty two percent of acute cholecystitis had positive cultures, compared with 24% of chronic cholecystitis (p = 0.03). E Coli was isolated in 51% of positive cases, Streptococci-Enterococci in 24%, Enterobacter sp in 9%, Klebsiella and Proteus in lower proportions. Salmonella sp was isolated in 4 cases, being all women with chronic cholecystitis. Thirteen of 29 cases with cancer or dysplasia had positive cultures (45%), compared with 25% of patients with inflammatory gallbladder diseases (p = 0.02). Streptococci-Enterococci were isolated in 7 cases and Enterobacter sp in three.

CONCLUSIONS

The presence of Salmonella sp in gallbladder bile was not frequent in the studied patients. Its role in the pathogenesis of gallbladder cancer must be reassessed.

Successful related umbilical cord blood transplantation for graft failure following T cell-depleted non-identical bone marrow transplantation in a child with major histocompatibility complex class II deficiency

Major histocompatibility complex (MHC) class II deficiency is a rare form of primary combined immunodeficiency that can only be corrected by stem cell transplantation. We report a 4(1/2)-year-old girl with MHC class II deficiency who underwent a related CBT due to graft failure following T cell-depleted non-identical BMT. The patient is alive and well 2 years after the second transplant. A sustained hematopoietic engraftment and a progressive immune recovery have been detected. We conclude that cord blood may be an effective source of hematopoietic stem cells for patients with immuno- deficiency disorders including diseases with a high rate of graft failure.

Improved success rate in reoperative parathyroidectomy with intraoperative PTH assay

OBJECTIVE

The clinical usefulness of preoperative localization and intraoperative PTH assay (QPTH) in primary hyperparathyroidism have been established. However, without the use of QPTH, the parathyroidectomy failure rate remains 5% to 10% in large reported series and is probably much higher in the hands of less experienced parathyroid surgeons. Persistent hypercalcemia requires another surgical procedure. The authors compared the outcomes in 50 consecutive patients undergoing more difficult secondary parathyroidectomy with and without the adjunctive support of QPTH.

METHODS

Two groups of similar patients underwent reoperative parathyroidectomy for failed surgery or recurrent disease. The successful return to normocalcemia in group I, with QPTH used to localize and confirm complete excision of all hyperfunctioning glands, was compared with group II, who did not have this intraoperative adjunct.

RESULTS

In 31/33 patients in group I, calcium levels returned to normal. With good preoperative localization studies, 17 patients underwent successful straightforward parathyroidectomies as predicted by QPTH. In the other 14 patients, QPTH assay proved extremely beneficial by facilitating localization with differential venous sampling; measuring the increase in hormone secretion after massage of specific areas; recognizing suspicious nonparathyroid tissue excised without a decrease in hormone levels, avoiding frozen-section delay; and correctly identifying the excision of abnormal tissue despite false-positive/false-negative sestamibi scans. In group II, who underwent surgery before QPTH was available, 4 of 17 patients (24%) remained hypercalcemic after extensive reexploration.

CONCLUSION

With the intraoperative hormone assay used to facilitate localization and confirm excision of all hyperfunctioning tissue, the success rate of reoperative parathyroidectomy has improved from 76% to 94%.

[Bone marrow transplantation for severe aplastic anemia]

Severe aplastic anemia is a hematological disease with a high mortality rate, for which bone marrow transplantation is the treatment of choice, specially in children and young adults. The number of transfusions undergone before the transplant is the most important factor to predict the possibility of graft failure. Twenty patients with severe aplastic anemia, most of them already multiple transfused, were transplanted utilizing cyclophosphamide combined with antilymphocyte globulin as a conditioning regiment. All the evaluable patients engrafted and there were no episodes of graft failure. Three patients died, and 17 (85%) are alive with hematopoietic recovery at a median of 27.7 months post-transplant. Bone marrow transplantation was an excellent therapeutic option in this series of patients with severe aplastic anemia and the conditioning regiment appeared to be sufficiently myeloablative and immunosuppressive to avoid early or late graft failure.

Accuracy of invasive and noninvasive tests to diagnose Helicobacter pylori infection after antibiotic treatment

OBJECTIVES

To compare the diagnostic accuracy of the most widely available tests for diagnosis of Helicobacter pylori infection after antibiotic treatment.

METHODS

A total of 59 H. pylori-positive, duodenal ulcer patients (mean age, 40.7 +/- 11.7 yr; 40 male and 19 female) were treated for 2 wk with either amoxicillin-metronidazole (n = 36) or omeprazole-amoxicillin-tinidazole (n = 23), and after 4 wk, were tested for H. pylori infection by [14C]urea breath test (UBT), serum IgG antibody level, and multiple antral biopsies for rapid urease testing, histology, Warthin-Starry stain, and polymerase chain reaction to detect H. pylori DNA. Infection status was established by a concordance of test results.

RESULTS

H. pylori was eradicated in 47 patients (80%). UBT and rapid urease testing had the best sensitivity and specificity, although not statistically different to Warthin-Starry stain and polymerase chain reaction. Serology and histology had little diagnostic value in this setting due to high proportion of false-positive results.

CONCLUSIONS

Noninvasive UBT is as accurate in predicting H. pylori status after antibiotic treatment as rapid urease testing and Warthin-Starry stain. Especially for duodenal ulcer patients, UBT could be considered the gold standard to confirm eradication of H. pylori.

Estrogen and luminal stimulation of rat uterine kallikrein

To understand the regulation of rat uterine kallikrein, we evaluated its variations in animals that had been ovariectomized and supplemented with estradiol or progesterone, in pseudopregnant animals intraluminally oil-stimulated or unstimulated, and in unilaterally pregnant animals. The content of kallikrein, determined by an RIA highly specific for rK1 (true tissue kallikrein), rose in ovariectomized rats with estradiol supplementation (0.28 +/- 0.03 to 0.44 +/- 0.05 ng/mg) and decreased with progesterone (0.13 +/- 0.02 ng/mg; n = 15; p < 0.001). Kallikrein content rose from Day 1 of pseudopregnancy (PP1) to a maximum on PP7 (0.18 +/- 0.01 to 0.39 +/- 0.04 ng/mg protein; n = 36; p < 0.001). On PP7 with unilateral oil intraluminal stimulation, the decidualized horn had higher kallikrein content than did the contralateral (0.98 +/- 0.09 vs. 0.35 +/- 0.05 ng/mg protein; n = 7; p < 0.001). Immunocytochemistry revealed that mainly rK1 is localized in the luminal and glandular epithelium, and it increased in the stimulated horn. In the unilaterally pregnant rat on Day 7, the fertile horn had a higher kallikrein content than its contralateral control (0.71 +/- 0.07 vs. 0.37 +/- 0.03 ng/mg protein, p < 0.001; n = 8), as well as a higher kininogenase activity (239 +/- 34.3 vs. 83.5 +/- 7.9 ng bradykinin(BK)/h per horn, p < 0.003; and 945 +/- 90 vs. 585 +/- 40 ng BK/h per gram tissue, p < 0.002; n = 6). These results indicate that estrogen stimulates, whereas progesterone inhibits, kallikrein production, and that hormonal regulation is overridden by intraluminal stimulation, thus associating the enzyme with decidualization.

Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2

The gene for spinocerebellar ataxia type 2 (SCA2) has been mapped to 12q24.1. A 1.1-megabase contig in the candidate region was assembled in P1 artificial chromosome and bacterial artificial chromosome clones. Using this contig, we identified a CAG trinucleotide repeat with CAA interruptions that was expanded in patients with SCA2. In contrast to other unstable trinucleotide repeats, this CAG repeat was not highly polymorphic in normal individuals. In SCA2 patients, the repeat was perfect and expanded to 36-52 repeats. The most common disease allele contained (CAG)37, one of the shortest expansions seen in a CAG expansion syndrome. The repeat occurs in the 5'-coding region of SCA2 which is a member of a novel gene family.