Safety and clinical activity of the Notch inhibitor, crenigacestat (LY3039478), in an open-label phase I trial expansion cohort of advanced or metastatic adenoid cystic carcinoma.

Background Deregulated Notch signaling is implicated in multiple cancers. The phase I trial (I6F-MC-JJCA) investigated the safety and anti-tumor activity of crenigacestat (LY3039478), a selective oral Notch inhibitor, in an expansion cohort of patients with adenoid cystic carcinoma (ACC) who received the dose-escalation-recommended phase 2 dose (RP2D), established previously (Massard C, et al., Annals Oncol 2018, 29:1911-17). Methods Patients with advanced or metastatic cancer, measurable disease, ECOG-PS ≤1, and baseline tumor tissue were enrolled. Primary objectives were to identify a safe RP2D, confirm this dose in expansion cohorts, and document anti-tumor activity. Secondary objectives included safety and progression-free survival (PFS). The ACC expansion cohort received the RP2D regimen of 50 mg crenigacestat thrice per week in a 28-day cycle until disease progression or other discontinuation criteria were met. Results Twenty-two patients with ACC were enrolled in the expansion cohort (median age of 60 years). Median treatment duration was 3 cycles with 6 patients remaining on treatment. There were no objective responses; 1 (5%) patient had an unconfirmed partial response. Disease control rate was 73% and 4 patients had stable disease ≥6 months. Median PFS was 5.3 months (95%CI: 2.4-NE)) for the 22 patients; and 7.7 months (95%CI: 4.0-NR) and 2.4 months (95%CI: 1.1-NE) in the subgroup of patients in second-line (n = 7) or ≥ third-line (n = 9), respectively. Frequent treatment-related-adverse events (all grades) included diarrhea, fatigue, vomiting, decreased appetite, dry mouth, and dry skin. There were no new safety signals. Conclusion The crenigacestat RP2D regimen induced manageable toxicity and limited clinical activity, without confirmed responses, in heavily pretreated patients with ACC.

First-in-human study of LY3039478, an oral Notch signaling inhibitor in advanced or metastatic cancer.

Background: Deregulated Notch signaling due to mutation or overexpression of ligands and/or receptors is implicated in various human malignancies. γ-Secretase inhibitors inhibit Notch signaling by preventing cleavage of transmembrane domain of Notch protein. LY3039478 is a novel, potent Notch inhibitor decreases Notch signaling and its downstream biologic effects. In this first-in-human study, we report the safety, pharmacokinetic (PK) profile, pharmacodynamic effects, and antitumor activity of LY3039478 in patients with advanced or metastatic cancer. Methods: This phase I, open-label, multicenter, nonrandomized, and dose-escalation phase study determined and confirmed the recommended phase II dose of LY3039478 (oral dose: 2.5-100 mg, thrice weekly (TIW) on a 28-day cycle). The primary objectives are to determine (part A) and confirm (part B) a recommended phase II dose that may be safely administered to patients with advanced or metastatic cancer, and secondary objectives include evaluation of safety, tolerability, PK parameters, and preliminary antitumor activity of LY3039478. Results: A total of 110 patients were treated with LY3039478 monotherapy between 31 October 2012 and 15 July 2016. Dose-limiting toxicities were thrombocytopenia, colitis, and nausea. Most adverse events were gastrointestinal. The recommended phase II dose was 50 mg TIW, because of its better tolerability compared with 75 mg. The PKs of LY3039478 appeared dose proportional. Pharmacodynamic data indicate an ∼80% inhibition of plasma Aß, and >50% inhibition of Notch-regulated genes hairy and enhancer of split-1, cyclin D1, and Notch-regulated ankyrin repeat at 45-100-mg dose. Clinical activity (tumor necrosis, metabolic response, or tumor shrinkage) was observed in patients with breast cancer, leiomyosarcoma, and adenoid cystic carcinoma. Conclusion: Potent inhibition of Notch signaling by LY3039478 was well tolerated at doses associated with target engagement, and demonstrated evidence of clinical activity in heavily pretreated patients. Further investigation with LY3039478 as monotherapy and in combination with targeted agent or chemotherapy is ongoing. Clinicaltrials.gov ID: NCT01695005.

Characteristics of macrolide responders in persistent post-surgical rhinosinusitis.

INTRODUCTION: The anti-inflammatory effects of long term low dose macrolide therapy have shown benefit in the management of diffuse panbronchiolitis. Dramatic responses to macrolide in the upper airway are seen but our understanding of the patient phenotype predisposing to macrolide response in chronic rhinosinusitis (CRS) is poor. METHODS: A case control study was performed in a tertiary level rhinology practice of consecutive chronic rhinosinusitis patients placed on a 3-month low dose macrolide therapy after failing at least 3 months of corticosteroid irrigation therapy post-endoscopic sinus surgery. Patients were defined as a macrolide responder when having near normal endoscopy after a 3-month period of clarithromycin treatment. Patient characteristics of smoking, asthma, atopy status, revision surgery, symptom severity (SNOT-22) along with biomarkers from serum and tissue histopathology results were compared between groups. RESULTS: Of twenty-eight consecutive macrolide treated patients, 19 responders were compared to 9 non-responders. The groups were similar in age, female gender, non-smoking, asthma, and atopy. Macrolide response was associated with a lack of tissue eosinophilia (more than 10/HPF) and lower serum eosinophilia. Neutrophil expression was similar in tissue and serum. Squamous metaplasia was overexpressed in non-responders. CONCLUSION: Low tissue and serum eosinophilia, and absence of tissue squamous metaplasia may predict a CRS phenotype suitable to a trial of long-term macrolide therapy when surgery and topical therapy has failed.

Association of gastro-oesophageal reflux and chronic rhinosinusitis: systematic review and meta-analysis.

INTRODUCTION: Gastro-oesophageal reflux disease (GORD) has been implicated in the development of chronic rhinosinusitis (CRS). The association of GORD with CRS is systematically assessed from the medical literature. METHODOLOGY: Embase and MEDLINE were searched using a comprehensive strategy limited to English language and Human subjects. Any study with original data on the experimental, diagnostic, treatment or prognostic association of CRS with GORD was included. Studies without a control group, case reports and review articles were excluded. RESULTS: The search returned 958 records, with an additional 10 found from bibliographic lists; this produced 32 studies. The included studies (n=32) consisted of studies reporting pathogenic factors (n=20), epidemiological association (n=8), prognostic interactions (n=3), and a combination of these outcomes (n=1). Potential pathogenic roles for GORD in CRS were supported; CRS subjects had greater prevalence of intranasal Helicobacter pylori and acid reflux than subjects without CRS. CRS is more prevalent in GORD sufferers than those without GORD. Evidence is conflicting for GORD as a factor in CRS treatment failure. CONCLUSION: The results support a significant association of GORD with CRS. Physicians should be cognizant of the potential for acid and non-acid reflux as a driving factor in CRS.

A case-control study to identify risk factors for acute salmonellosis in New Zealand dairy herds, 2011-2012.

In late 2011 the New Zealand Ministry for Primary Industries reported an increase in confirmed laboratory diagnoses of salmonellosis in dairy herds. To identify risk factors for herd-level outbreaks of salmonellosis we conducted a case-control study of New Zealand dairy herds in 2011-2012. In a multivariable analysis, use of continuous feed troughs [adjusted odds ratio (aOR) 6·2, 95% confidence interval (CI) 2·0-20], use of pelletized magnesium supplements (aOR 10, 95% CI 3·3-33) and use of palm kernel meal as a supplementary feed (aOR 8·7, 95% CI 2·5-30) were positively associated with a herd-level outbreak of salmonellosis between 1 July 2011 and 31 January 2012. We conclude that supplementary feeds used on dairy farms (regardless of type) need to be stored and handled appropriately to reduce the likelihood of bacterial contamination, particularly from birds and rodents. Magnesium supplementation in the pelletized form played a role in triggering outbreaks of acute salmonellosis in New Zealand dairy herds in 2011-2012.

A phase 1b study of crenigacestat (LY3039478) in combination with gemcitabine and cisplatin or gemcitabine and carboplatin in patients with advanced or metastatic solid tumors.

BACKGROUND: Notch signaling plays an integral role in development and tissue homeostasis. Inhibition of Notch signaling has been identified as a reasonable target for oncotherapy. Crenigacestat (LY3039478) is a potent Notch inhibitor that decreases Notch signaling and its downstream biologic effects. METHODS: I6F-MC-JJCD was a multicenter, nonrandomized, open-label, phase 1b study with 5 separate, parallel dose escalations in patients with advanced or metastatic cancer from a variety of solid tumors followed by a dose-confirmation phase in pre-specified tumor types. This manuscript reports on 2 of 5 groups. The primary objective was to determine the recommended phase 2 dose of crenigacestat combined with other anticancer agents (gemcitabine/cisplatin or gemcitabine/carboplatin). Secondary objectives included evaluation of safety, tolerability, preliminary efficacy, and pharmacokinetics. RESULTS: Patients (N = 31) received treatment between November 2016 and July 2019. Dose-limiting toxicities occurred in 6 patients. The recommended phase 2 dose for crenigacestat was 50 mg TIW in Part 1 (combined with gemcitabine/cisplatin) and not established in Part 2 (combined with gemcitabine/carboplatin) due to poor tolerability. Patients had at least one treatment-emergent adverse event (TEAE), and most had Grade ≥ 3 TEAEs. Over 50% of the patients experienced gastrointestinal disorders (Grade ≥ 3). No patient had complete response; 5 patients had a partial response. Disease control rates were 62.5% (Part 1) and 60.0% (Part 2). CONCLUSION: This study demonstrated that the Notch inhibitor, crenigacestat, combined with different anticancer agents (gemcitabine, cisplatin, and carboplatin) was poorly tolerated and resulted in disappointing clinical activity in patients with advanced or metastatic solid tumors. CLINICALTRIALS: gov Identification Number: NCT02784795.

Collagen matrix as an inlay in endoscopic skull base reconstruction.

BACKGROUND: Multi-layer reconstruction has become standard in endoscopic skull base surgery. The inlay component used can vary among autografts, allografts, xenografts and synthetics, primarily based on surgeon preference. The short- and long-term outcomes of collagen matrix in skull base reconstruction are described. METHODS: A case series of patients who underwent endoscopic skull base reconstruction with collagen matrix inlay were assessed. Immediate peri-operative outcomes (cerebrospinal fluid leak, meningitis, ventriculitis, intracranial bleeding, epistaxis, seizures) and delayed complications (delayed healing, meningoencephalocele, prolapse of reconstruction, delayed cerebrospinal fluid leak, ascending meningitis) were examined. RESULTS: Of 120 patients (51.0 ± 17.5 years, 41.7 per cent female), peri-operative complications totalled 12.7 per cent (cerebrospinal fluid leak, 3.3 per cent; meningitis, 3.3 per cent; other intracranial infections, 2.5 per cent; intracranial bleeding, 1.7 per cent; epistaxis, 1.7 per cent; and seizures, 0 per cent). Delayed complications did not occur in any patients. CONCLUSION: Collagen matrix is an effective inlay material. It provides robust long-term separation between sinus and cranial cavities, and avoids donor site morbidity, but carries additional cost.

UV-induced hyperphosphorylation of replication protein a depends on DNA replication and expression of ATM protein.

Exposure to DNA-damaging agents triggers signal transduction pathways that are thought to play a role in maintenance of genomic stability. A key protein in the cellular processes of nucleotide excision repair, DNA recombination, and DNA double-strand break repair is the single-stranded DNA binding protein, RPA. We showed previously that the p34 subunit of RPA becomes hyperphosphorylated as a delayed response (4-8 h) to UV radiation (10-30 J/m(2)). Here we show that UV-induced RPA-p34 hyperphosphorylation depends on expression of ATM, the product of the gene mutated in the human genetic disorder ataxia telangiectasia (A-T). UV-induced RPA-p34 hyperphosphorylation was not observed in A-T cells, but this response was restored by ATM expression. Furthermore, purified ATM kinase phosphorylates the p34 subunit of RPA complex in vitro at many of the same sites that are phosphorylated in vivo after UV radiation. Induction of this DNA damage response was also dependent on DNA replication; inhibition of DNA replication by aphidicolin prevented induction of RPA-p34 hyperphosphorylation by UV radiation. We postulate that this pathway is triggered by the accumulation of aberrant DNA replication intermediates, resulting from DNA replication fork blockage by UV photoproducts. Further, we suggest that RPA-p34 is hyperphosphorylated as a participant in the recombinational postreplication repair of these replication products. Successful resolution of these replication intermediates reduces the accumulation of chromosomal aberrations that would otherwise occur as a consequence of UV radiation.

Association of Ki-ras with amplified DNA sequences, detected in human ovarian carcinomas by a modified in-gel renaturation assay.

A modified in-gel DNA renaturation technique, which detects DNA sequences amplified greater than 7-fold in human DNA, was used to analyze gene amplification in surgical specimens of primary and metastatic ovarian carcinomas. Amplified DNA sequences were detected in two of eight tumors. Hybridization of these samples with different oncogene probes revealed that both tumors contained an amplified Ki-ras gene, which in one case was coamplified with c-myc. In one of the tumors, Ki-ras was found to be amplified in both the primary tumor and three different metastatic nodules. No mutations at codons 12 or 61 of Ki-ras were detected in these tumors. No additional cases of Ki-ras or c-myc amplification were detected by Southern hybridization in the tumors that were found to be amplification negative by modified in-gel renaturation assays. These results indicate that gene amplification in ovarian carcinomas is likely to involve the Ki-ras oncogene.

Does oral folic acid lower total homocysteine levels and improve endothelial function in children with chronic renal failure?

BACKGROUND: Accelerated vascular disease is common in chronic renal failure (CRF) and accounts for significant mortality and morbidity. Elevated homocysteine levels may contribute by an effect on endothelial function. METHODS AND RESULTS: We performed a double-blind placebo-controlled randomized crossover trial of folic acid at 5 mg/m2 in 25 normotensive children 12+/-3 (7 to 17) years of age with CRF (glomerular filtration rate 26.8+/-13.2 mL/min per 1.73 m2) of noninflammatory etiology. Each subject underwent two 8-week periods of folic acid and placebo separated by an 8-week washout period. The effect of folic acid on homocysteine levels, LDL oxidation, and both endothelial-dependent and -independent vascular function were measured. After oral folic acid, serum folate levels rose from 11.7+/-4.25 to 635+/-519 microg/L (P=0.001), red cell folate levels rose from 364+/-195 to 2891+/-2623 microg/L (P<0.001), and total homocysteine levels fell from 10.28+/-4.16 to 8.62+/-2.32 micromol/L (P=0.03). In addition, there was a significant improvement in flow-mediated dilatation (FMD) (endothelial-dependent dilatation) from 7.21+/-2.8% to 8.47+/-3.01% (P=0.036) with no change in response to glyceryl trinitrate (endothelial-independent dilatation). There was no significant change in FMD or glyceryl trinitrate during the placebo phase. There was, however, no significant difference in final FMD after placebo or folic acid. Lag times for LDL oxidation were prolonged during the treatment phase (58.4+/-18.7 to 68.1+/-25.9 minutes, P=0.01). CONCLUSION: Folic acid supplementation in children with CRF may improve endothelial function with an increased resistance of LDL to oxidation.

Mental stress induces transient endothelial dysfunction in humans.

BACKGROUND: Mental stress has been linked to increased morbidity and mortality in coronary artery disease and to atherosclerosis progression. Experimental studies have suggested that damage to the endothelium may be an important mechanism. METHODS AND RESULTS: Endothelial function was studied in 10 healthy men (aged 50. 4+/-9.6 years) and in 8 non-insulin-dependent diabetic men (aged 52. 0+/-7.2 years). Brachial artery flow-mediated dilation (FMD, endothelium dependent) and response to 50 microg of sublingual glyceryl trinitrate (GTN, endothelium independent) were measured noninvasively by use of high-resolution ultrasound before and after (30, 90, and 240 minutes) a standardized mental stress test. The same protocol without mental stress was repeated on a separate occasion in the healthy men. In healthy subjects, FMD (5.0+/-2.1%) was significantly (P:<0.01) reduced at 30 and 90 minutes after mental stress (2.8+/-2.3% and 2.3+/-2.4%, respectively) and returned toward normal after 4 hours (4.1+/-2.0%). Mental stress had no effect on the response to GTN. In the repeated studies without mental stress, FMD did not change. The diabetic subjects had lower FMD than did the control subjects (3.0+/-1.5% versus 5.0+/-2.1%, respectively; P:=0.02) but showed no changes in FMD (2.7+/-1.1% after 30 minutes, 2.8+/-1.9% after 90 minutes, and 3.1+/-2.3% after 240 minutes) or GTN responses after mental stress. CONCLUSIONS: These findings suggest that brief episodes of mental stress, similar to those encountered in everyday life, may cause transient (up to 4 hours) endothelial dysfunction in healthy young individuals. This might represent a mechanistic link between mental stress and atherogenesis.

Asymptomatic myocardial ischemia in diabetes and its relationship to diabetic neuropathy: an exercise electrocardiography study in middle-aged diabetic men.

The incidence of painless ischemic heart disease is increased in diabetic patients, and it has been suggested that this may be partly due to diabetic neuropathy involving cardiac afferent nerves. We have performed exercise electrocardiography in middle-aged diabetic men without cardiac symptoms to see if silent myocardial ischemia is more common in patients with neuropathy. Thirty patients had diabetic neuropathy (group 1), and 30 did not (group 2). The groups were matched for age and duration of diabetes. The exercise test was abnormal in 14 patients. A positive test was no more common in patients with diabetic neuropathy. During a mean follow-up period of 50 mo, five patients developed clinical heart disease, four of whom had a positive exercise test. An abnormal exercise ECG is common in diabetic men without cardiac symptoms, but our study does not suggest that the high incidence of silent myocardial ischemia in diabetic patients is related to the presence of diabetic neuropathy. In patients with diabetes a positive exercise test is associated with a high risk of developing clinical heart disease in subsequent years.

A multiple-source method for studying the prevalence of developmental disabilities in children: the Metropolitan Atlanta Developmental Disabilities Study.

The Metropolitan Atlanta Developmental Disabilities Study is the first US, population-based epidemiologic study of the prevalence of mental retardation, cerebral palsy, hearing impairment, and visual impairment among school-age children. The study population consisted of children who were 10 years of age between 1985 and 1987 and whose mothers were residents of the five Georgia counties of Clayton, Cobb, DeKalb, Fulton, and Gwinnett at the time of the child's birth. Since children with developmental disabilities are identified by and receive services from various health, social service, and education systems, a multiple-source case identification method was used. This study is unique in that individual school records were used to identify children with the four disabilities. Use of a multiple-source method made it possible to confirm specific conditions and to classify subtypes of disabilities. About 95% of the children with one or more of these four disabilities were initially identified through the school systems. This approach is much less costly than conducting medical and psychologic assessments on populations of children. In addition, this method made it possible to estimate accurately the "administrative prevalence" of these disabilities (ie, the number of children previously identified with these disabilities for the purpose of providing services). The prevalence rates found in this study, per 1000 10-year-old children, were as follows: mental retardation, 10.3; cerebral palsy, 2.0; hearing impairment, 1.0; and visual impairment, 0.6.(ABSTRACT TRUNCATED AT 250 WORDS)

5,10 Methylenetetrahydrofolate reductase genetic polymorphism as a risk factor for neural tube defects.

Persons with a thermolabile form of the enzyme 5,10 methylenetetrahydrofolate reductase (MTHFR) have reduced enzyme activity and increased plasma homocysteine which can be lowered by supplemental folic acid. Thermolability of the enzyme has recently been shown to be caused by a common mutation (677C-->T) in the MTHFR gene. We studied 41 fibroblast cultures from NTD-affected fetuses and compared their genotypes with those of 109 blood specimens from individuals in the general population. 677C-->T homozygosity was associated with a 7.2 fold increased risk for NTDs (95% confidence interval: 1.8-30.3; p value: 0.001). These preliminary data suggest that the 677C-->T polymorphism of the MTHFR gene is a risk factor for spina bifida and anencephaly that may provide a partial biologic explanation for why folic acid prevents these types of NTD.

Early and late patency of expanded polytetrafluoroethylene vascular grafts in aorta-coronary bypass.

Expanded polytetrafluoroethylene (PTFE) (Gore-Tex) grafts were used in 16 patients with ischemic heart disease undergoing aorta-coronary bypass graft operations. PTFE was used only when insufficient suitable vein was available. A total of 27 grafts were inserted in 16 patients. Eighteen grafts (in 11 patients) were studied in the early (3 months) postoperative period. Eleven were patent. Nine expanded PTFE grafts in six patients were restudied between 12 and 29 months after insertion. Six were patent. Factors affecting graft patency were similar to those governing patency of vein grafts. There was a high incidence of complications, but the patients constituted a poor-risk group. It is reasonable to use expanded PTFE grafts when insufficient vein is available. Such grafts can remain patent and functional for at least 2 years.

Congenital malformations surveillance: two American systems.

As part of its epidemiologic studies of congenital malformations, the Centers for Disease Control (CDC) conducts two birth defects surveillance systems in the United States. The Metropolitan Atlanta Congenital Defects Programme (MACDP) is an intensive surveillance system using several methods to identify infants born with birth defects in the Atlanta area. The Birth Defects Monitoring Programme (BDMP) is a nationwide surveillance system that monitors 1 million births per year, about a third of all births in the U.S. It relies on diagnoses from newborn discharge summaries to ascertain affected infants. The systems were originally designed to detect potential 'epidemics' of birth defects that could occur following the widespread dissemination of new teratogens similar to thalidomide. In addition to monitoring, they have also proved to be useful resources for a variety of studies of the epidemiology of birth defects.

Resection of the pubic bone as an adjunct to management of primary, recurrent, and metastatic pelvic malignancies.

Patients with locally advanced vulvovaginal carcinomas with pubic bone encroachment or fixation pose a treatment dilemma. The purpose of this study was to evaluate the outcome in 12 patients who have undergone pubic bone resection at the University of Minnesota as part of treatment of locally extensive primary, recurrent, or metastatic vulvovaginal carcinomas. Six patients with primary vulvar carcinomas and six patients with recurrent or metastatic vulvovaginal carcinomas underwent bone resection as part of their surgical therapy. Survival in the primary treatment group was 50%, with no local recurrences. Survival in the recurrent/metastatic disease group was 83%, with a follow-up time of 9 months to 15 years. One vulvar and one groin recurrence have occurred in the recurrent/metastatic group. Pubic bone resection added little to surgical morbidity and gave good functional results. Pubic bone resection, in combination with radical extirpative procedures, is an option for treatment of patients with locally extensive vulvovaginal carcinomas, particularly those with previous radiation therapy.

XPA protein alters the specificity of ultraviolet light-induced mutagenesis in vitro.

Studies of ultraviolet (UV) light mutagenesis have demonstrated mutations at common sites in the target genes of shuttle vector plasmids replicated in cultured cells or by cellular extracts. The reasons for the specific pattern of mutagenesis are largely unknown. We have examined the specificity of UV-induced mutagenesis by replicating plasmid pLS189, irradiated with 40 J/m(2) UVC or unirradiated, in either xeroderma pigmentosum group A (XP-A) or HeLa cellular extracts. The XP-A extract displayed slightly lower replication ability, but produced a higher mutant frequency, compared to that of HeLa extract. Use of irradiated plasmid inhibited replication by an average of 63% and increased the mutant frequency by an average of 16.7-fold. Analysis of mutation spectra revealed nonrandom patterns of mutagenesis that differed significantly between HeLa and XP-A extracts. In comparison to HeLa extract, replication in XP-A extract resulted in lower frequencies of GC --> AT transitions and tandem double-base substitutions, and a higher frequency of deletions. Replication in HeLa extract produced hotspots at positions 100, 108, and 156 that were not produced by XP-A extract. Furthermore, XP-A extract produced hotspots at positions 124, 133, and 164, sites not characteristic of previous UV-induced mutagenesis studies using XPA-expressing cells. Addition of purified XPA protein to reactions containing XP-A extract altered each of these parameters, including loss of the hotspots at positions 124 and 133, to yield a more HeLa-like spectrum. These results indicate a previously uncharacterized role of the XPA protein in influencing the specificity of UV-induced mutagenesis during DNA replication.

Expression of ATM in ataxia telangiectasia fibroblasts rescues defects in DNA double-strand break repair in nuclear extracts.

Ataxia telangiectasia (A-T) is a human genetic disorder characterized by progressive cerebellar degeneration, hypersensitivity to ionizing radiation (IR), immunodeficiency, and high cancer risk. At the cellular level, IR sensitivity and increased frequency of spontaneous and IR-induced chromosomal breakage and rearrangements are the hallmarks of A-T. The ATM gene, mutated in this syndrome, has been cloned and codes for a protein sharing homology with DNA-PKcs, a protein kinase involved in DNA double-strand break (DSB) repair and DNA damage responses. The characteristics of the A-T cellular phenotypes and ATM gene suggest that ATM may play a role similar to that of DNA-PKcs in DSB repair and that there is a primary DNA repair defect in A-T cells. In the current study, the function of ATM in DNA DSB repair was evaluated in an in vitro system using two plasmids, carrying either an EcoRI-induced DSB within the lacZalpha gene or various endonuclease-induced DSB in the SupF suppressor tRNA gene. We found that the DSB repair efficiency in A-T nuclear extracts was comparable to, if not higher than, that in normal nuclear extracts. However, the repair fidelity in A-T nuclear extracts was decreased when repairing DSB with short 5' and 3' overhangs (<4 base pairs (bp)) or blunt ends, but not 5' 4-bp overhangs. Sequencing of the mutant plasmids revealed that deletions involving 1-6 nucleotide microhomologies were the major class of mutations in both A-T and normal extracts. However, the size of the deletions in plasmids from A-T nuclear extracts was larger than that from normal nuclear extracts. Expression of the ATM protein in A-T cells corrected the defect in DSB repair in A-T nuclear extracts. These results suggest that ATM plays a role in maintaining genomic stability by preventing the repair of DSB from an error-prone pathway.

Failed intrauterine device contraception and limb reduction deformities: a case-control study.

Three recent case reports have suggested an association between failed intrauterine device (IUD) contraception and limb reduction deformities in the resulting offspring. To clarify further the purported teratogenic role of the IUD in the etiology of these defects, we conducted a case-control study of 96 mothers who had given birth to infants with limb defects. Interview data about IUD exposure at conception among these mothers were compared with interview data from 2 sets of controls: (1) 915 mothers of infants with other major defects and (2) a subset of the first group consisting of 169 mothers with chromosomally defective infants. No significant increase in the incidence of IUD use was found for cases when compared with either control group. Estimates of the relative risk were 1.28 (95% confidence limits [CL]of 0.29 to 5.67) and 1.78 (95% CL of 0.25 to 12.82) when the first and second groups of controls were used, respectively. These risk figures were not significantly different from 1.0. The evidence accumulated thus far militates against a teratogenic role for the IUD.