Douglas W. Theriaque

Fecal microbiota in premature infants prior to necrotizing enterocolitis.

Intestinal luminal microbiota likely contribute to the etiology of necrotizing enterocolitis (NEC), a common disease in preterm infants. Microbiota development, a cascade of initial colonization events leading to the establishment of a diverse commensal microbiota, can now be studied in preterm infants using powerful molecular tools. Starting with the first stool and continuing until discharge, weekly stool specimens were collected prospectively from infants with gestational ages ≤32 completed weeks or birth weights≤1250 g. High throughput 16S rRNA sequencing was used to compare the diversity of microbiota and the prevalence of specific bacterial signatures in nine NEC infants and in nine matched controls. After removal of short and low quality reads we retained a total of 110,021 sequences. Microbiota composition differed in the matched samples collected 1 week but not <72 hours prior to NEC diagnosis. We detected a bloom (34% increase) of Proteobacteria and a decrease (32%) in Firmicutes in NEC cases between the 1 week and <72 hour samples. No significant change was identified in the controls. At both time points, molecular signatures were identified that were increased in NEC cases. One of the bacterial signatures detected more frequently in NEC cases (p<0.01) matched closest to γ-Proteobacteria. Although this sequence grouped to the well-studied Enterobacteriaceae family, it did not match any sequence in Genbank by more than 97%. Our observations suggest that abnormal patterns of microbiota and potentially a novel pathogen contribute to the etiology of NEC.

Distinct phenotypes distinguish the molecular classes of Angelman syndrome

BACKGROUND Angelman syndrome (AS) is a severe neurobehavioural disorder caused by defects in the maternally derived imprinted domain located on 15q11-q13. Most patients acquire AS by one of five mechanisms: (1) a large interstitial deletion of 15q11-q13; (2) paternal uniparental disomy (UPD) of chromosome 15; (3) an imprinting defect (ID); (4) a mutation in the E3 ubiquitin protein ligase gene (UBE3A); or (5) unidentified mechanism(s). All classical patients from these classes exhibit four cardinal features, including severe developmental delay and/or mental retardation, profound speech impairment, a movement and balance disorder, and AS specific behaviour typified by an easily excitable personality with an inappropriately happy affect. In addition, patients can display other characteristics, including microcephaly, hypopigmentation, and seizures. METHODS We restricted the present study to 104 patients (93 families) with a classical AS phenotype. All of our patients were evaluated for 22 clinical variables including growth parameters, acquisition of motor skills, and history of seizures. In addition, molecular and cytogenetic analyses were used to assign a molecular class (I-V) to each patient for genotype-phenotype correlations. RESULTS In our patient repository, 22% of our families had normal DNA methylation analyses along 15q11-q13. Of these, 44% of sporadic patients had mutations withinUBE3A, the largest percentage found to date. Our data indicate that the five molecular classes can be divided into four phenotypic groups: deletions, UPD and ID patients,UBE3A mutation patients, and subjects with unknown aetiology. Deletion patients are the most severely affected, while UPD and ID patients are the least. Differences in body mass index, head circumference, and seizure activity are the most pronounced among the classes. CONCLUSIONS Clinically, we were unable to distinguish between UPD and ID patients, suggesting that 15q11-q13 contains the only significant maternally expressed imprinted genes on chromosome 15.

Intestinal Microbial Ecology in Premature Infants Assessed with Non-Culture-Based Techniques

OBJECTIVES To use high throughput techniques to analyze intestinal microbial ecology in premature neonates, who are highly susceptible to perturbations of the luminal environment associated with necrotizing enterocolitis (NEC) and late-onset sepsis. STUDY DESIGN With non-culture-based techniques, we evaluated intestinal microbiota shortly after birth and during hospitalization in 23 neonates born at 23 to 32 weeks gestational age. Microbiota compositions were compared in 6 preterm infants in whom NEC, signs of systemic inflammation, or both developed with matched control subjects by using 16S ribosomal RNA pyrosequencing. RESULTS Microbial DNA was detected in meconium, suggesting an intrauterine origin. Differences in diversity were detected in infants whose mothers intended to breast feed (P = .03), babies born to mothers with chorioamnionitis (P = .06), and in babies born at <30 weeks gestation (P = .03). A 16S ribosomal RNA sequence analysis detected Citrobacter-like sequences only in cases with NEC (3 of 4) and an increased frequency of Enterococcus-like sequences in cases and Klebsiella in control subjects (P = .06). The overall microbiota profiles in cases with NEC were not distinguishable from that in control subjects. CONCLUSIONS Microbial DNA in meconium of premature infants suggests prenatal influences.

Controlled Clinical Trial of Dichloroacetate for Treatment of Congenital Lactic Acidosis in Children

OBJECTIVE. Open-label studies indicate that oral dichloroacetate (DCA) may be effective in treating patients with congenital lactic acidosis. We tested this hypothesis by conducting the first double-blind, randomized, control trial of DCA in this disease. METHODS. Forty-three patients who ranged in age from 0.9 to 19 years were enrolled. All patients had persistent or intermittent hyperlactatemia, and most had severe psychomotor delay. Eleven patients had pyruvate dehydrogenase deficiency, 25 patients had 1 or more defects in enzymes of the respiratory chain, and 7 patients had a mutation in mitochondrial DNA. Patients were preconditioned on placebo for 6 months and then were randomly assigned to receive an additional 6 months of placebo or DCA, at a dose of 12.5 mg/kg every 12 hours. The primary outcome results were (1) a Global Assessment of Treatment Efficacy, which incorporated tests of neuromuscular and behavioral function and quality of life; (2) linear growth; (3) blood lactate concentration in the fasted state and after a carbohydrate meal; (4) frequency and severity of intercurrent illnesses and hospitalizations; and (5) safety, including tests of liver and peripheral nerve function. OUTCOME. There were no significant differences in Global Assessment of Treatment Efficacy scores, linear growth, or the frequency or severity of intercurrent illnesses. DCA significantly decreased the rise in blood lactate caused by carbohydrate feeding. Chronic DCA administration was associated with a fall in plasma clearance of the drug and with a rise in the urinary excretion of the tyrosine catabolite maleylacetone and the heme precursor δ-aminolevulinate. CONCLUSIONS. In this highly heterogeneous population of children with congenital lactic acidosis, oral DCA for 6 months was well tolerated and blunted the postprandial increase in circulating lactate. However, it did not improve neurologic or other measures of clinical outcome.

Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: a randomized, triple-masked, placebo-controlled study.

Background:The authors tested the hypotheses that, compared with an overnight continuous femoral nerve block (cFNB), a 4-day ambulatory cFNB increases ambulation distance and decreases the time until three specific readiness-for-discharge criteria are met after tricompartment total knee arthroplasty. Methods:Preoperatively, all patients received a cFNB (n = 50) and perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomly assigned to either continue perineural ropivacaine or switch to perineural normal saline. Primary endpoints included (1) time to attain three discharge criteria (adequate analgesia, independence from intravenous analgesics, and ambulation of at least 30 m) and (2) ambulatory distance in 6 min the afternoon after surgery. Patients were discharged with their cFNB and a portable infusion pump, and catheters were removed on postoperative day 4. Results:Patients given 4 days of perineural ropivacaine attained all three discharge criteria in a median (25th–75th percentiles) of 25 (21–47) h, compared with 71 (46–89) h for those of the control group (estimated ratio, 0.47; 95% confidence interval, 0.32–0.67; P <0.001). Patients assigned to receive ropivacaine ambulated a median of 32 (17–47) m the afternoon after surgery, compared with 26 (13–35) m for those receiving normal saline (estimated ratio, 1.21; 95% confidence interval, 0.71–1.85; P = 0.42). Conclusions:Compared with an overnight cFNB, a 4-day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 53% after tricompartment total knee arthroplasty. However, the extended infusion did not increase ambulation distance the afternoon after surgery. (ClinicalTrials.gov No. NCT00135889.)

Ambulatory continuous interscalene nerve blocks decrease the time to discharge readiness after total shoulder arthroplasty: a randomized, triple-masked, placebo-controlled study.

Background:A continuous interscalene nerve block (CISB) may be used to provide analgesia after shoulder arthroplasty. Therefore, inpatient stays may be shortened if CISB (1) provides adequate analgesia without intravenous opioids and (2) improves shoulder mobilization. This study investigated the relationship between ambulatory CISB and the time to reach three discharge criteria after shoulder arthroplasty. Methods:Preoperatively, patients received a CISB. All patients received a perineural 0.2% ropivacaine infusion from surgery until 06:00 the following morning, at which time they were randomly assigned either to continue perineural ropivacaine or to switch to normal saline. The primary endpoint was the time from the end of surgery until three discharge criteria were attained (adequate analgesia, independence from intravenous analgesics, and tolerance to 50% of shoulder motion targets). Patients were discharged home as early as the afternoon after surgery with their CISB using a portable infusion pump. Results:Patients receiving perineural ropivacaine (n = 16) attained all three discharge criteria in a median (10th–90th percentiles) of 21 (16–41) h, compared with 51 (37–90) h for those receiving perineural normal saline (n = 13, P < 0.001). Unlike patients receiving perineural ropivacaine, patients receiving perineural normal saline often required intravenous morphine, but still experienced a higher degree of pain and tolerated less external rotation. Conclusions:An ambulatory CISB considerably decreases the time until readiness for discharge after shoulder arthroplasty, primarily by providing potent analgesia that permits greater passive shoulder movement and the avoidance of intravenous opioids. Additional research is required to define the appropriate subset of patients and assess the incidence of complications associated with earlier discharge.

One-year protocol liver biopsy can stratify fibrosis progression in liver transplant recipients with recurrent hepatitis C infection:

Determinants of progression to cirrhosis in hepatitis C virus (HCV) infection have been well described in the immunocompetent population but remain poorly defined in liver transplant (LT) recipients. This cohort study determines the factors contributing to the development of fibrosis and its rate of progression in the allograft. Predictive factors analyzed include: demographics, host and donor factors, surgery‐related variables (cold and warm ischemia time), rejection episodes, cytomegalovirus infection (CMV), and immunosuppression. Over 12 years, 842 adult LTs were performed at our institution; 358 for the indication of HCV. A total of 264 patients underwent protocol liver biopsies at month 4 and yearly after LT. Using the modified Knodell system of Ishak for staging fibrosis, the median fibrosis progression rate was .8 units/year (P < .001). Rapid fibrosis progression (>.8 units/year) was best identified by liver histology performed at 1 year. Donor age > 55 years was associated with rapid fibrosis progression and development of cirrhosis (P < .001). In contrast, donor age < 35 years was associated with slower progression of fibrosis (P = .003). Risk factors for graft loss due to recurrent HCV included recipient age > 35 years (P = .01), donor age > 55 years (P = .005), and use of female donor allografts (P = .03). In conclusion, fibrosis progression in HCV‐infected LT recipients occurs at a rate of .8 units/year. Increased donor age has a major impact on disease progression, graft failure, and patient survival. A liver biopsy performed at 1 year posttransplant can help identify those patients more likely to develop progressive disease and may allow better targeting of antiviral therapy. (Liver Transpl 2004;10:1240–1247.)

Peripheral artery tonometry demonstrates altered endothelial function in children with type 1 diabetes.

Objectives:  To assess the ability of reactive hyperemia–peripheral artery tonometry (RH‐PAT) to serve as a surrogate marker of endothelial dysfunction in children with type 1 diabetes (T1D).

A Multicenter, Randomized, Triple-Masked, Placebo-Controlled Trial of The Effect of Ambulatory Continuous Femoral Nerve Blocks on Discharge-Readiness Following Total Knee Arthroplasty In Patients on General Orthopaedic Wards

&NA; A continuous femoral nerve block (cFNB) involves the percutaneous insertion of a catheter adjacent to the femoral nerve, followed by a local anesthetic infusion, improving analgesia following total knee arthroplasty (TKA). Portable infusion pumps allow infusion continuation following hospital discharge, raising the possibility of decreasing hospitalization duration. We therefore used a multicenter, randomized, triple‐masked, placebo‐controlled study design to test the primary hypothesis that a 4‐day ambulatory cFNB decreases the time until each of three predefined readiness‐for‐discharge criteria (adequate analgesia, independence from intravenous opioids, and ambulation ≥30 m) are met following TKA compared with an overnight inpatient‐only cFNB. Preoperatively, all patients received a cFNB with perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomized to either continue perineural ropivacaine (n = 39) or switch to normal saline (n = 38). Patients were discharged with their cFNB and portable infusion pump as early as postoperative day 3. Patients who were given 4 days of perineural ropivacaine attained all three criteria in a median (25th–75th percentiles) of 47 (29–69) h, compared with 62 (45–79) h for those of the control group (Estimated ratio = 0.80, 95% confidence interval: 0.66–1.00; p = 0.028). Compared with controls, patients randomized to ropivacaine met the discharge criterion for analgesia in 20 (0–38) versus 38 (15–64) h (p = 0.009), and intravenous opioid independence in 21 (0–37) versus 33 (11–50) h (p = 0.061). We conclude that a 4‐day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 20% following TKA compared with an overnight cFNB, primarily by improving analgesia.

Evaluation of long-term treatment of children with congenital lactic acidosis with dichloroacetate.

OBJECTIVE. The purpose of this research was to report results on long-term administration of dichloroacetate in 36 children with congenital lactic acidosis who participated previously in a controlled trial of this drug. PATIENTS AND METHODS. We conducted a randomized control trial, followed by an open-label study. Data were analyzed for each patient from the time they began treatment through May 2005. RESULTS.Subject exposure to dichloroacetate totaled 110.42 years. Median height and weight increased over time, but the standardized values declined slightly and remained below the first percentile. There were no significant changes in biochemical metabolic indices, except for a 2% rise in total protein and a 22% increase in 24-hour urinary oxalate. Both the basal and carbohydrate meal-induced rises in lactate were blunted by dichloroacetate. The median cerebrospinal fluid lactate also decreased over time. Conduction velocity decreased and distal latency increased in peroneal nerves. Mean 3-year survival for all of the subjects was 79%. CONCLUSIONS. Oral dichloroacetate is generally well tolerated in young children with congenital lactic acidosis. Although continued dichloroacetate exposure is associated with evidence of peripheral neuropathy, it cannot be determined whether this is attributable mainly to the drug or to progression of underlying disease.