Citations

Background— Autopsy-negative sudden unexplained death, including sudden infant death syndrome, can be caused by cardiac channelopathies such as Brugada syndrome (BrS). Type 1 BrS, caused by mutations in the SCN5A -encoded sodium channel, accounts for ≈20% of BrS. Recently, a novel mutation in the glycerol-3-phosphate dehydrogenase 1–like gene ( GPD1-L ) disrupted trafficking of SCN5A in a multigenerational family with BrS. We hypothesized that mutations in GPD1-L may be responsible for some cases of sudden unexplained death/sudden infant death syndrome. Methods and Results— Using denaturing high-performance liquid chromatography and direct DNA sequencing, we performed comprehensive open-reading frame/splice site mutational analysis of GPD1-L on genomic DNA extracted from necropsy tissue of 83 unrelated cases of sudden unexplained death (26 females, 57 males; average age, 14.6±10.7 years; range, 1 month to 48 years). A putative, sudden unexplained death–associated GPD1-L missense mutation, E83K, was discovered in a 3-month-old white boy. Further mutational analysis was then performed on genomic DNA derived from a population-based cohort of 221 anonymous cases of sudden infant death syndrome (84 females, 137 males; average age, 3±2 months; range, 3 days to 12 months), revealing 2 additional mutations, I124V and R273C, in a 5-week-old white girl and a 1-month-old white boy, respectively. All mutations occurred in highly conserved residues and were absent in 600 reference alleles. Compared with wild-type GPD1-L, GPD1-L mutations coexpressed with SCN5A in heterologous HEK cells produced a significantly reduced sodium current ( P <0.01). Adenovirus-mediated gene transfer of the E83K–GPD1-L mutation into neonatal mouse myocytes markedly attenuated the sodium current ( P <0.01). These decreases in current density are consistent with sodium channel loss-of-function diseases like BrS. Conclusions— The present study is the first to report mutations in GPD1-L as a pathogenic cause for a small subset of sudden infant death syndrome via a secondary loss-of-function mechanism whereby perturbations in GPD1-L precipitate a marked decrease in the peak sodium current and a potentially lethal BrS-like proarrhythmic substrate.

The purpose of this study was to evaluate the short-term outcomes after laparoscopic and conventional parastomal hernia repairs. A retrospective review of parastomal hernia repairs was performed. Conventional repairs included primary suture repair, stoma relocation, and mesh repair. Laparoscopic repairs included the Sugarbaker and keyhole techniques. Forty-nine patients underwent repair of symptomatic parastomal hernias: 19 ileostomies, 13 colostomies, and 17 urostomies. Thirty patients underwent 39 conventional repairs. Nineteen patients underwent laparoscopic surgical repairs. Operative times were longer for laparoscopic repair (208 ± 58 vs 162 ± 114 minutes, P = .06). The mean length of stay was 6 days for both groups ( P = .74). The mean follow-up was shorter in the laparoscopic group (20 vs 65 months, P ≤ .001). There were no significant differences in the incidence of surgical site infections (11% laparoscopic vs 5% conventional, P = .60) or complication rates (63% laparoscopic vs 36% conventional, P = .67). Laparoscopic parastomal hernia repair is a feasible operation with similar short-term outcomes to conventional repairs.

For many years, β-adrenergic receptor antagonists (β-blockers or βAR antagonists) have provided significant morbidity and mortality benefits in patients who have sustained acute myocardial infarction. More recently, β-adrenergic receptor antagonists have been found to provide survival benefits in patients suffering from heart failure, although the efficacy of different β-blockers varies widely in this condition. One drug, carvedilol, a nonsubtype-selective βAR antagonist, has proven particularly effective in the treatment of heart failure, although the mechanism(s) responsible for this are controversial. Here, we report that among 16 clinically relevant βAR antagonists, carvedilol displays a unique profile of in vitro signaling characteristics. We observed that in β2 adrenergic receptor (β2AR)-expressing HEK-293 cells, carvedilol has inverse efficacy for stimulating G s -dependent adenylyl cyclase but, nonetheless, stimulates ( i ) phosphorylation of the receptor's cytoplasmic tail on previously documented G protein-coupled receptor kinase sites; ( ii ) recruitment of β-arrestin to the β2AR; ( iii ) receptor internalization; and ( iv ) activation of extracellular regulated kinase 1/2 (ERK 1/2), which is maintained in the G protein-uncoupled mutant β2AR T68F,Y132G,Y219A (β2AR TYY ) and abolished by β-arrestin2 siRNA. Taken together, these data indicate that carvedilol is able to stabilize a receptor conformation which, although uncoupled from G s , is nonetheless able to stimulate β-arrestin-mediated signaling. We hypothesize that such signaling may contribute to the special efficacy of carvedilol in the treatment of heart failure and may serve as a prototype for a new generation of therapeutic β2AR ligands.

Background Percutaneous coronary revascularization (PCI) has been increasingly applied to unprotected left main trunk (LMT) lesions, with varied long-term success. This study attempts to define the predictors of outcome in this population. Methods and Results Two hundred seventy-nine consecutive patients who had LMT PCI at 1 of 25 sites between 1993 and 1998 were studied. Forty-six percent of these patients were deemed inoperable or at high surgical risk. Thirty-eight patients (13.7%) died in hospital, and the rest were followed up for a mean of 19 months. The 1-year incidence was 24.2% for all-cause mortality, 20.2% for cardiac mortality, 9.8% for myocardial infarction, and 9.4% for CABG. Independent correlates of all-cause mortality were left ventricular ejection fraction ≤30%, mitral regurgitation grade 3 or 4, presentation with myocardial infarction and shock, creatinine ≥2.0 mg/dL, and severe lesion calcification. For the 32% of patients <65 years old with left ventricular ejection fraction >30% and without shock, the prevalence of these adverse risk factors was low. No periprocedural deaths were observed in this low-risk subset, and the 1-year mortality was only 3.4%. Conclusions Patients undergoing unprotected LMT PCI have frequent serious comorbidities and consequently have high event rates. PCI may be an alternative to CABG for a select proportion of elective patients and may also be appropriate for highly symptomatic inoperable patients. Meticulous follow-up of hospital survivors is required because of the rather high mortality during the first few months after treatment.

AbstractBackground: Assay of methylated DNA markers in stool is a promising approach for colorectal cancer (CRC) screening. A method to capture hypermethylated CpG islands from stool would enrich target analyte and allow optimal assay sensitivity.Methods: Methyl-binding domain (MBD) protein was produced using a pET6HMBD plasmid with MBD DNA sequence cloned from rat MeCP2 gene and bound to a column of nickel-agarose resin. We first established the feasibility of using the MBD column to extract methylated human DNA in a high background of fecal bacterial DNA. To explore the impact of MBD enrichment on detection sensitivity, the tumor-associated methylated vimentin gene was assayed with methylation-specific PCR from stools to which low amounts of cancer cell DNA (0–50 ng) were added and from stools from CRC patients and healthy individuals. Stools from cancer patients were selected with low amounts of human DNA (median 7 ng, range 0.5–832 ng).Results: With MBD enrichment, methylated vimentin was detected in stools enriched with ≥10 ng of cancer cell DNA and in CRC stool with a range of native human DNA amounts from 4 to 832 ng. Without MBD enrichment, methylated vimentin was not detected in the enriched stools and was detected in only 1 cancer stool with high human DNA (832 ng). In stools from healthy individuals methylated vimentin was not detected, with or without MBD enrichment.Conclusions: MBD capture increases assay sensitivity for detecting methylated DNA markers in stool. Applied clinical studies for stool cancer screening are indicated.