Increased susceptibility to vancomycin-resistant Enterococcus intestinal colonization persists after completion of anti-anaerobic antibiotic treatment in mice.

BACKGROUND: Antibiotic-associated disruption of the indigenous intestinal microflora may persist beyond the treatment period. Although piperacillin/tazobactam inhibits the establishment of vancomycin-resistant Enterococcus (VRE) stool colonization in mice during treatment, we hypothesized that this agent and other anti-anaerobic antibiotics would increase susceptibility to colonization during the period of recovery of the intestinal microflora. DESIGN: Mice received 10(4) colony-forming units of vancomycin-resistant E. faecium by orogastric inoculation 2, 5, or 10 days after completing 5 days of subcutaneous antibiotic treatment, or both during and 2 days after the completion of treatment. Denaturing gradient gel electrophoresis (DGGE) was performed to assess changes in the intestinal microflora. RESULTS: Anti-anaerobic antibiotics (ie, piperacillin/ tazobactam, cefoxitin, and clindamycin) caused significant disruption of the indigenous microflora (mean DGGE similarity indices < or = 27% in comparison with saline controls) and promoted the establishment of high-density colonization when VRE was inoculated 2 or 5, but not 10, days following treatment (P < .001). Piperacillin/tazobactam exhibited a biphasic effect on the establishment of colonization (ie, inhibition when exposed to VRE during treatment and promotion when exposed to VRE after discontinuation of treatment), resulting in greater overall promotion of colonization than did agents with minimal anti-anaerobic activity (ie, levofloxacin, cefepime, and aztreonam) when VRE was inoculated both during and 2 days after treatment (P < .001). CONCLUSION: Patients receiving anti-anaerobic antibiotics, including piperacillin/tazobactam, may be susceptible to the establishment of high-density VRE colonization during the period of recovery of the anaerobic microflora.     

Outcomes after intravesical bacillus Calmette-Guerin are not affected by substaging of high grade T1 transitional cell carcinoma

PURPOSE: Substaging of T1 bladder tumors into T1a and T1b based on invasion of the tumor superficial to and beyond the muscularis mucosa has been assigned prognostic significance. We determined whether outcomes after intravesical bacillus Calmette-Guerin (BCG) differ between stage T1a and T1b subcategories. MATERIALS AND METHODS: Retrospective pathological evaluation of the initial transurethral resection specimens of stage T1 bladder tumors was performed by 2 pathologists. Grade 1, 2 or 3 and stage T1a or T1b were assigned to each case. Followup was from the date of transurethral resection to date of death or the last visit. Kaplan-Meier probability and log rank test were used to evaluate recurrence and progression. RESULTS: Substaging was performed in 49 of the 55 patients (89%) with stage T1 disease. Disease was stage T1a in 32 (65%), stage T1b in 17 (35%), grade 3 in 45 (92%) and grade 2 in 4 (8%) cases. Maximum followup was 147 months (median 71) and 28 cases had a minimum of 5 years of followup. Recurrence was noted in 33 cases (67.3%), including 22 stage T1a (69%) and 11 stage T1b (65%), at a median followup of 11.3 and 8.6 months, respectively. Progression to a higher stage of disease was recorded in 12 cases (24.4%), including 7 (22%) stage T1a and 5 (29%) stage T1b, at a median followup of 108 and 120 months, respectively. The difference between T1a and T1b subcategories was not statistically significant in regard to recurrence-free (p = 0.7203) and progression-free (p = 0.574) outcomes. CONCLUSIONS: Substaging of T1 tumors did not affect response to BCG in regard to recurrence or progression. Therefore, intravesical BCG is effective for stages T1a and T1b disease.     

High stem cell frequency in acute myeloid leukemia at diagnosis predicts high minimal residual disease and poor survival.

PURPOSE: In CD34-positive acute myeloid leukemia (AML), the leukemia-initiating event originates from the CD34(+)CD38(-) stem cell compartment. Survival of these cells after chemotherapy may lead to minimal residual disease (MRD) and subsequently to relapse. Therefore, the prognostic impact of stem cell frequency in CD34-positive AML was investigated. EXPERIMENTAL DESIGN: First, the leukemogenic potential of unpurified CD34(+)CD38(-) cells, present among other cells, was investigated in vivo using nonobese diabetic/severe combined immunodeficient mice transplantation experiments. Second, we analyzed whether the CD34(+)CD38(-) compartment at diagnosis correlates with MRD frequency after chemotherapy and clinical outcome in 92 AML patients. RESULTS: In vivo data showed that engraftment of AML blasts in nonobese diabetic/severe combined immunodeficient mice directly correlated with stem cell frequency of the graft. In patients, a high percentage of CD34(+)CD38(-) stem cells at diagnosis significantly correlated with a high MRD frequency, especially after the third course of chemotherapy. Also, it directly correlated with poor survival. In contrast, total CD34(+) percentage showed no such correlations. CONCLUSIONS: Both in vivo data, as well as the correlation studies, show that AML stem cell frequency at diagnosis offers a new prognostic factor. From our data, it is tempting to hypothesize that a large CD34(+)CD38(-) population at diagnosis reflects a higher percentage of chemotherapy-resistant cells that will lead to the outgrowth of MRD, thereby affecting clinical outcome. Ultimately, future therapies should be directed toward malignant stem cells.     

MYC amplification and polysomy 8 in chondrosarcoma: array comparative genomic hybridization, fluorescent in situ hybridization, and association with outcome.

PURPOSE: To identify recurrent regions of genomic gain or loss in chondrosarcoma in a clinically relevant and statistically valid fashion. Materials and METHODS: Array comparative genomic hybridization (CGH) results of 15 frozen tumor samples of high-grade chondrosarcoma for chromosome 8 are presented. A separate subset of 116 cartilaginous tumors with outcome data was used for validation. RESULTS: Array CGH identified gain at 8q24.12-q24.13, the region of the MYC (c-Myc) oncogene, as a frequent change in high-grade chondrosarcoma. In the validation arm of 116 cartilaginous tumors, MYC was frequently amplified in G2 (15%), G3 (20%), and dedifferentiated (21%) chondrosarcomas. No amplification was identified in samples of enchondroma and grade 1 chondrosarcoma. In samples without MYC amplification, polysomy 8 was a frequent finding in grade 1 (18%), grade 2 (31%), grade 3 (80%), and dedifferentiated (29%) chondrosarcomas, but was not found in any samples of enchondroma. MYC protein expression was identified in all samples with amplification, but was also frequent in the remaining samples without amplification or polysomy 8. Kaplan-Meier survival curves for overall survival showed a statistically significant difference for patients with MYC amplification or polysomy 8 (P = .034). Univariate analysis involving Cox proportional hazards models showed that grade (P = .003), polysomy 8 (P = .045), and MYC amplification (P = .053) correlated with shorter overall survival. By multivariate analysis, grade of chondrosarcoma (P = .026) was the only factor to reach statistical significance. CONCLUSION: MYC amplification and polysomy 8 can be used as markers of prognostic importance in chondrosarcoma. Molecular targeting of MYC expression may have therapeutic potential in the future for subsets of chondrosarcoma.     

Evaluation of the extent of under-reporting of serious adverse drug reactions: the case of toxic epidermal necrolysis.

INTRODUCTION: Toxic epidermal necrolysis (TEN) is a life-threatening adverse drug reaction (ADR) that is primarily the result of drug exposure (incidence 0.4-1.3 per million person-years). Life-threatening ADRs such as TEN should be reported to ADR monitoring programmes, which collect reports for suspected ADRs and alert the public and medical practitioners to new drug hazards. In Canada, reports are made to the Canadian Adverse Drug Reaction Monitoring Program (CADRMP). OBJECTIVE: To examine the extent of under-reporting for TEN in Canada. DESIGN: A retrospective case series design was used to collect all TEN cases for the period January 1995 to December 2000. METHODS: The CADRMP and 22 burn centres across Canada were contacted for all TEN patients treated during the specified time period. PATIENT GROUPS STUDIED: The study population consisted of patients admitted to burn treatment sites across Canada, patient cases reported to the CADRMP and patient cases recorded by the Canadian Institute for Health Information (CIHI) hospital discharge summaries as the International Classification of Diseases Version 9 Clinical Modification (ICD-9-CM) code 695.1. RESULTS: Twenty-five TEN cases (six fatal) were reported to CADRMP from January 1995 to December 2000. During this period, 14 (63.6%) burn treatment sites reported admission of 250 TEN cases. Hospital discharge summaries using the ICD-9-CM code 695.1 indicated that 4349 cases were admitted to hospital during this time period and it was estimated that 15.5% (n = 674) of these cases were TEN. Using the burn facility data as the denominator, 10% (25 of 250) of TEN cases were reported to CADRMP. Using CIHI data as a denominator, only 4% (25 of 674) of TEN cases were reported to CADRMP. CONCLUSIONS: There is serious under-reporting of TEN. Lack of reporting of life-threatening ADRs can compromise population safety. There is a need to increase awareness of ADR reporting programmes.     

Exome sequencing in individuals with cardiovascular laterality defects identifies potential candidate genes

The birth prevalence of laterality defects is about 1.1/10,000 comprising different phenotypes ranging from situs inversus totalis to heterotaxy, mostly associated with complex congenital heart defects (CHD) and situs abnormalities such as intestinal malrotation, biliary atresia, asplenia, or polysplenia. A proportion of laterality defects arise in the context of primary ciliary dyskinesia (PCD) accompanied by respiratory symptoms or infertility. In this study, exome sequencing (ES) was performed in 14 case-parent trios/quattros with clinical exclusion of PCD prior to analysis. Moreover, all cases and parents underwent detailed clinical phenotyping including physical examination, echocardiography by a skilled paediatric cardiologist and abdominal ultrasound examinations not to miss mildly affected individuals. Subsequent survey of the exome data comprised filtering for monoallelic de novo, rare biallelic, and X-linked recessive variants. In two families, rare variants of uncertain significance (VUS) in PKD1L1 and ZIC3 were identified. Both genes have been associated with laterality defects. In two of the remaining families, biallelic variants in LMBRD1 and DNAH17, respectively, were prioritized. In another family, an ultra-rare de novo variant in WDR47 was found. Extensive exome survey of 2,109 single exomes of individuals with situs inversus totalis, heterotaxy, or isolated CHD identified two individuals with novel monoallelic variants in WDR47, but no further individuals with biallelic variants in DNAH17 or LMBRD1. Overall, ES of 14 case-parent trios/quattros with cardiovascular laterality defects identified rare VUS in two families in known disease-associated genes PKD1L1 and ZIC3 and suggests DNAH17, LMBRD1, and WDR47 as potential genes involved in laterality defects.Subject terms: Disease genetics, Genetic counselling, Biological sciences     

Systematic Evidence Map for Over One Hundred and Fifty Per- and Polyfluoroalkyl Substances (PFAS)

Background: Per- and polyfluoroalkyl substances (PFAS) are a large class of synthetic (man-made) chemicals widely used in consumer products and industrial processes. Thousands of distinct PFAS exist in commerce. The 2019 U.S. Environmental Protection Agency (U.S. EPA) Per- and Polyfluoroalkyl Substances (PFAS) Action Plan outlines a multiprogram national research plan to address the challenge of PFAS. One component of this strategy involves the use of systematic evidence map (SEM) approaches to characterize the evidence base for hundreds of PFAS.Objective: SEM methods were used to summarize available epidemiological and animal bioassay evidence for a set of ∼150 PFAS that were prioritized in 2019 by the U.S. EPA’s Center for Computational Toxicology and Exposure (CCTE) for in vitro toxicity and toxicokinetic assay testing.Methods: Systematic review methods were used to identify and screen literature using manual review and machine-learning software. The Populations, Exposures, Comparators, and Outcomes (PECO) criteria were kept broad to identify mammalian animal bioassay and epidemiological studies that could inform human hazard identification. A variety of supplemental content was also tracked, including information on in vitro model systems; exposure measurement–only studies in humans; and absorption, distribution, metabolism, and excretion (ADME). Animal bioassay and epidemiology studies meeting PECO criteria were summarized with respect to study design, and health system(s) were assessed. Because animal bioassay studies with ≥21-d exposure duration (or reproductive/developmental study design) were most useful to CCTE analyses, these studies underwent study evaluation and detailed data extraction. All data extraction is publicly available online as interactive visuals with downloadable metadata.Results: More than 40,000 studies were identified from scientific databases. Screening processes identified 44 animal and 148 epidemiology studies from the peer-reviewed literature and 95 animal and 50 epidemiology studies from gray literature that met PECO criteria. Epidemiological evidence (available for 15 PFAS) mostly assessed the reproductive, endocrine, developmental, metabolic, cardiovascular, and immune systems. Animal evidence (available for 40 PFAS) commonly assessed effects in the reproductive, developmental, urinary, immunological, and hepatic systems. Overall, 45 PFAS had evidence across animal and epidemiology data streams.Discussion: Many of the ∼150 PFAS were data poor. Epidemiological and animal evidence were lacking for most of the PFAS included in our search. By disseminating this information, we hope to facilitate additional assessment work by providing the initial scoping literature survey and identifying key research needs. Future research on data-poor PFAS will help support a more complete understanding of the potential health effects from PFAS exposures. https://doi.org/10.1289/EHP10343