Common patterns of gene regulation associated with Cesarean section and the development of islet autoimmunity - indications of immune cell activation.

Birth by Cesarean section increases the risk of developing type 1 diabetes later in life. We aimed to elucidate common regulatory processes observed after Cesarean section and the development of islet autoimmunity, which precedes type 1 diabetes, by investigating the transcriptome of blood cells in the developing immune system. To investigate Cesarean section effects, we analyzed longitudinal gene expression profiles from peripheral blood mononuclear cells taken at several time points from children with increased familial and genetic risk for type 1 diabetes. For islet autoimmunity, we compared gene expression differences between children after initiation of islet autoimmunity and age-matched children who did not develop islet autoantibodies. Finally, we compared both results to identify common regulatory patterns. We identified the pentose phosphate pathway and pyrimidine metabolism - both involved in nucleotide synthesis and cell proliferation - to be differentially expressed in children born by Cesarean section and after islet autoimmunity. Comparison of global gene expression signatures showed that transcriptomic changes were systematically and significantly correlated between Cesarean section and islet autoimmunity. Moreover, signatures of both Cesarean section and islet autoimmunity correlated with transcriptional changes observed during activation of isolated CD4+ T lymphocytes. In conclusion, we identified shared molecular changes relating to immune cell activation in children born by Cesarean section and children who developed autoimmunity. Our results serve as a starting point for further investigations on how a type 1 diabetes risk factor impacts the young immune system at a molecular level.

Haplotyping and estimation of haplotype frequencies for closely linked biallelic multilocus genetic phenotypes including nuclear family information.

With the discovery of single nucleotide polymorphisms (SNP) along the genome, genotyping of large samples of biallelic multilocus genetic phenotypes for (fine) mapping of disease genes or for population studies has become standard practice. A genetic trait, however, is mainly caused by an underlying defective haplotype, and populations are best characterized by their haplotype frequencies. Therefore, it is essential to infer from the phase-unknown genetic phenotypes in a sample drawn from a population the haplotype frequencies in the population and the underlying haplotype pairs in the sample in order to find disease predisposing genes by some association or haplotype sharing algorithm. Haplotype frequencies and haplotype pairs are estimated via a maximum likelihood approach by a well-known expectation maximization (EM) algorithm, adapting it to a large number (up to 30) of biallelic loci (SNP), and including nuclear family information, if available, into the analysis. Parents are treated as an independent sample from the population. Their genotyped offspring reduces the number of potential haplotype pairs for both parents, resulting in a higher accuracy of the estimation, and may also reduce computation time. In a series of simulations our approach of including nuclear family information has been tested against both the EM algorithm without nuclear family information and an alternative approach using GENEHUNTER for the haplotyping of the families, using the locus-by-locus allele counts of the sample. Our new approach is more precise in haplotyping in cases of a high number of heterozygous loci, whereas for a moderate number of heterozygous positions in the sample all three different approaches gave the same perfect results.

A fluorimeter-based RT-PCR method for the detection and quantitation of porcine cytokines.

In this paper, we describe a fluorimeter-based, closed-tube, polymerase chain reaction (PCR) assay for the detection and quantification of the mRNA of porcine interleukin 1alpha (IL1alpha) and interleukin 2 (IL2) cytokines in peripheral blood leukocytes (PBLs) using melting curve analysis and compare it to a standard PCR performed in a block-based thermocycler.

The composition of gas given by mouth-to-mouth ventilation during CPR.

STUDY OBJECTIVE: To compare the concentration of a rescuer's exhaled O2 and CO2 during mouth-to-mouth ventilation with or without chest compression. DESIGN: Prospective repeated measures study. Simulated one- and two-rescuer cardiopulmonary resuscitation (CPR) was performed as recommended by the American Heart Association. SETTING: University laboratory. PARTICIPANTS: Fifty-five healthcare professionals certified in basic and advanced cardiac life support volunteered as rescuers in this study. MEASUREMENTS AND RESULTS: Thirty-three volunteers performed one-rescuer CPR, and 22 volunteers performed two-rescuer CPR. Minute ventilation for both groups increased 50% to 130% during CPR (p < 0.05). During the performance of CPR, the concentration of exhaled O2 increased from 16.4 +/- 0.7% to 16.9 +/- 0.5% in the one-rescuer CPR group and from 16.5 +/- 0.9% to 17.8 +/- 0.6% in the two-rescuer CPR group (p < 0.05). The concentration of exhaled CO2 in the one-rescuer CPR group did not change significantly throughout the entire experiment, but decreased in the two-rescuer CPR group from a baseline measurement of 4.0 +/- 0.6% to 3.5 +/- 0.4% (p < 0.05). During CPR, the concentration of exhaled CO2 was 4.0 +/- 0.4% in the one-rescuer CPR group compared with 3.5 +/- 0.4% in the two-rescuer CPR group (p < 0.05). CONCLUSIONS: The gas given by mouth-to-mouth ventilation is a hypercarbic and hypoxic mixture compared with room air. Mouth-to-mouth ventilation is the only circumstance in which a hypercarbic and hypoxic gas is given as therapy. Further laboratory and clinical studies are necessary to determine the effect of mouth-to-mouth ventilation during CPR.

Pharmacokinetics of felbamate, a novel antiepileptic drug: application of mixed-effect modeling to clinical trials.

Felbamate is a novel antiepileptic drug currently undergoing clinical trials in the United States. Serum felbamate concentration data from a phase II safety and efficacy trial were analyzed using NONMEM. A one-compartment, open model with first-order absorption and elimination was used. Body weight, sex, concurrent folic acid therapy, and phenytoin dose and dose:concentration ratio did not affect the estimates for felbamate clearance (Cl). Carbamazepine dose and dose:concentration ratio (CDCR) led to significant improvements in the objective function. The final models for felbamate clearance and volume of distribution (Vd) were as follows: Cl(L/hr) = 2.43 + 0.429*CDCR/240, Vd (L) = 51. The coefficient of variation of clearance was only about 12%, which may be indicative of the highly selective patient population. The clearance estimates are similar to those obtained in healthy volunteers and in patients receiving lower dosages of felbamate. The volume of distribution estimate, however, is slightly smaller than that reported previously. Valuable pharmacokinetic information can be obtained from the routine monitoring of serum concentrations during safety and efficacy trials.

Ventilation caused by external chest compression is unable to sustain effective gas exchange during CPR: a comparison with mechanical ventilation.

OBJECTIVE: To compare the tidal volume, minute ventilation, and gas exchange caused by mechanical chest compression with and without mechanical ventilatory support during cardiopulmonary resuscitation (CPR) in a laboratory model of cardiac arrest. DESIGN: A laboratory swine model of CPR was used. Eight animals with and eight animals without mechanical ventilation received chest compression (100/min) for 10 min. Coronary perfusion pressure, tidal volume, and minute ventilation were recorded continuously. INTERVENTIONS: Ventricular fibrillation for 6 min without CPR, then mechanical chest compression for 10 min. RESULTS: During the first minute of chest compression, mean (+/- S.D.) minute ventilation was 11.2 +/- 5.9 l/min in the mechanically ventilated group and 4.5 +/- 2.8 l/min in the group without mechanical ventilation (P = 0.01). Minute ventilation gradually declined to 5.8 +/- 1.4 l/min and 1.7 +/- 1.6 l/min, respectively, during the last minute of chest compression (P < 0.0001). After 10 min of chest compression, mean arterial pH was significantly more acidemic in the group without mechanical ventilation (7.16 +/- 0.13 compared with 7.30 +/- 0.07 units) and PCO2 was higher (62 +/- 19 compared with 35 +/- 9 mmHg). Mixed venous PCO2 was also higher (76 +/- 15 compared with 61 +/- 8 mmHg). CONCLUSION: Standard chest compression alone produced measurable tidal volume and minute ventilation. However, after 10 min of chest compression following 6 min of untreated ventricular fibrillation, it failed to sustain pulmonary gas exchange as indicated by significantly greater arterial and mixed venous hypercarbic acidosis when compared with a group receiving mechanical ventilation.

Absorption and safety of rectally administered phenytoin.

Parenteral phenytoin solution (Dilantin) was given rectally three times a day for three days to two beagle dogs. This was well tolerated, with no evidence of mucosal irritation noted either on endoscopic nor on rectal mucosal biopsy. When given in this manner, phenytoin is absorbed to a limited degree in canines. Parenteral phenytoin solution can be safely administered rectally, despite a pH of 12. Further study in normal volunteers is needed to assess the usefulness of this route of administration in situations in which the oral and/or parenteral route of administration is unavailable.

Myocardial infarction after toluene inhalation.

Hydrocarbon exposure occurs through both intentional and nonintentional substance abuse. We present the case of a young male who sustained an acute myocardial infarction temporally related to inhalation of toluene fumes. We propose possible mechanisms for this rare but serious complication of hydrocarbon inhalation and review the literature.

Serum glucose after intraperitoneal infusion of 5% dextrose solution.

STUDY OBJECTIVE: This study investigated the use of intraperitoneal (IP) glucose infusion as a therapy for hypoglycemia. DESIGN: Randomized, placebo-controlled, crossover design, with each animal serving as its own control. SETTING: Laboratory investigation. TYPE OF PARTICIPANTS: Seven female New Zealand White rabbits with a mean weight of 3.7 kg. INTERVENTIONS: Each animal was subjected to three experiments separated by a four-day period. After baseline measurements, the following interventions were undertaken: Control day, no treatment; placebo day, 10 mL/kg 0.9% normal saline solution IP; and treatment day, 10 mL/kg 5% dextrose solution IP. MEASUREMENTS AND MAIN RESULTS: Serial serum glucose levels were obtained. Compared with control and placebo, the mean absolute serum glucose value of the treatment group was significantly higher beginning at ten minutes after intervention and continuing until conclusion of the study at 30 minutes. For these time points, the mean increase in serum glucose levels (percent change) of the treatment group compared with the control group was as follows: ten minutes, 15.5 mg/dL (0.86 mmol/L) (11%), P less than .01; 15 minutes, 20.6 mg/dL (1.14 mmol/L) (14%), P less than .01; 20 minutes, 36.5 mg/dL (2.03 mmol/L) (26%), P less than .001; and 30 minutes, 34.7 mg/dL (1.93 mmol/L) (24%), P less than .001. CONCLUSION: Glucose instilled into the peritoneal cavity of rabbits is absorbed rapidly into the systemic circulation.

Inefficacy of intraperitoneal fluid administration in a shock model.

Intraperitoneal (IP) fluid administration has been previously used to treat dehydrated children. The relative ease and reported safety of this route suggests its potential utility for volume resuscitation in the acutely ill child. Previous research regarding IP fluid infusion has not examined its use in shock states. This experiment sought to examine the efficacy of an IP fluid infusion in a shock model. Ten immature swine were randomized to receive either no treatment (n = 5) or 30 ml/kg of warmed lactated Ringer's solution (n = 5) IP 20 minutes after a graded 40% hemorrhage. Mean arterial pressure (MAP), heart rate (HR), hematocrit (Hct), pH, and PCO2 were determined serially, and the experiment concluded 60 minutes after intervention. A mean of 89.5% of the administered fluid load was recovered from the peritoneal cavity, and the IP infusion had no ameliorative effect on MAP or HR. The lack of clinically significant absorption of an administered isotonic intraperitoneal fluid infusion in this model suggests that this route should not be relied upon in the critically ill child presenting in shock.

Effect of felbamate on phenytoin and carbamazepine serum concentrations.

Felbamate (FBM) is a novel antiepileptic drug (AED) undergoing clinical trials in the United States. During a double-blind, cross-over clinical trial, patients received concomitant phenytoin (PHT) and carbamazepine (CBZ). Dosages of PHT and CBZ were adjusted to maintain serum concentrations +/- 20 and +/- 25% of baseline values. All patients required a PHT dosage decrease of 10-30% during active FBM treatment to maintain stable concentrations. CBZ serum concentrations decreased significantly in patients receiving active FBM. The mean decrease was 1.3 micrograms/ml and occurred in 30 of 32 patients. Therefore, FBM apparently causes a bidirectional effect on the serum concentrations of PHT and CBZ when all three drugs are taken concomitantly.

Beam reshaping by use of spatial solitons in the quadratic nonlinear medium KTP.

We have demonstrated the transformation of elliptical beams into cylindrically symmetric beams through the formation of quadratic spatial solitons. By use of type II phase-matched second-harmonic generation in a KTP crystal, input elliptical beams with aspect ratios as large as 8:1 were propagated through the KTP crystal, and they exited the crystal as a cylindrically symmetric beam. The threshold for soliton formation and the power throughput were measured versus ellipticity.

Quadratic spatial soliton generation by seeded downconversion of a strong harmonic pump beam.

Two-dimensional quadratic spatial solitons were generated experimentally near phase-matching conditions for type II frequency doubling in KTP by the seeding of a strong second-harmonic field with a weak input at the fundamental wavelength. The self-trapped beams were shown to be insensitive to the energy, phase, and polarization of the fundamental-frequency seed input beam.

Properties of type II quadratic solitons excited by imbalanced fundamental waves.

It was shown experimentally for type II second-harmonic generation in KTP that the family of quadratic spatial solitons exists over a wide range of imbalances for the two fundamental wave inputs. The threshold for soliton formation was measured as a function of both phase mismatch and relative input fraction of the energy in the two fundamental polarizations. Launching unequal fundamental inputs led to an imbalanced three-coupled-field output composition.

Lack of uniform definitions and reporting in laboratory models of cardiac arrest: a review of the literature and a proposal for guidelines.

BACKGROUND: Researchers are interested in improved uniformity of definitions and standards of reporting data for human CPR studies, and international guidelines (Utstein style) have been developed. However, no guidelines exist for animal CPR investigations. OBJECTIVE: To assess published animal CPR studies for adequacy of reporting and uniformity of methods and definitions regarding such important factors as the interval from the onset of ventricular fibrillation to the start of CPR (the nonintervention interval), ventilation, chest compression, coronary perfusion pressure, and return of spontaneous circulation. DESIGN: A blinded review of the methodology described in 42 articles concerned with animal CPR research published during the last ten years. An article had to report cardiac arrest and CPR as part of the protocol and return of spontaneous circulation as one of the outcome variables in order to be included in this study. We excluded abstracts, nonresuscitation models, and human CPR studies. MEASUREMENTS AND MAIN RESULTS: There was wide variation in the experimental methods reported in the studies. The nonintervention interval ranged from 0 to 15 minutes. The majority of studies initiated CPR within three minutes after the onset of ventricular fibrillation. Twenty-two percent of studies reported tidal volume, and 18% reported minute ventilation. Of the 14 studies that used blood pressure or coronary perfusion pressure as a target for titration of chest compression force, 12 used different target blood pressure values. We found 29 different definitions of return of spontaneous circulation. The duration of return of spontaneous circulation ranged from 30 seconds to 60 minutes; however, 52% of studies did not report a duration. CONCLUSION: Important differences exist in animal CPR research methodology among laboratories. Failure to define or report minute ventilation, coronary perfusion pressure, and return of spontaneous circulation made it difficult to compare studies. In order to make valid comparisons of studies, blood flow and ventilation should be measured and controlled when they are not experimental variables. Uniform definitions and guidelines for reporting should be developed for laboratory CPR research.

Modulation of cyclin transcript levels in cultured cells of Arabidopsis thaliana.

Previous studies on the cell cycle of Arabidopsis thaliana have been hindered by the lack of synchronous cell culture systems. We have used liquid callus cultures and a cycloheximide-synchronized suspension culture of Arabidopsis to investigate changes in cyclin transcript levels in response to exogenous auxin, cytokinin, and nutrients, and during the cell cycle. CYCD1 (delta 1) transcript was virtually undetectable in liquid-cultured callus or suspension-culture cells. CYCD2 (delta 2) transcript levels were largely unaffected by the readdition of phytohormones or nitrate to the growth medium, and remained constant throughout the cell cycle in suspension-culture cells. CYCD3 (delta 3) transcript levels were strongly dependent on nitrate, and were induced at the G1/S transition following phytohormone readdition. In synchronized suspension-culture cells, CYCD3 transcript accumulated during the S phase, and remained constant thereafter. These results support the hypothesis that D cyclins function as part of the cellular machinery that integrates diverse signals impinging upon commitment to cell division. In synchronized cells transcripts of the mitotic cyclins CYC1, CYC2, and CYC3 reached a maximum with peak mitotic index, but CYC3 transcript levels increased earlier than those of CYC1 or CYC2. The kinetics of accumulation of CYC transcript levels support their classification as A-type (CYC3) and B-type (CYC1 and CYC2) cyclins, respectively.

Progabide-induced changes in carbamazepine metabolism.

Carbamazepine (CBZ) and carbamazepine 10,11 epoxide (CBZ-E) concentrations were measured during a safety and efficacy trial of progabide. The average CBZ and CBZ-E serum concentrations were calculated from serial measurements during placebo and active treatment periods. Significant decreases in CBZ and significant increases in CBZ-E were observed after the first dose of progabide, and these changes persisted during 3 months of active treatment. Ninety-five percent of the patients had increases in the epoxide/CBZ ratio at the end of 3 months of treatment. These changes are consistent with displacement of CBZ from protein binding sites and inhibition of CBZ-E metabolism induced by progabide and are analagous to the interaction between valproate and CBZ.

Evaluation of canisters for measuring emissions of volatile organic air pollutants from hazardous waste incineration.

Regulation to control air emissions of toxic organic compounds require the collection and analysis of effluent gas from low level sources such as hazardous waste incinerators. The standard SW-846 Method specifies the use of Tenax and Tenax/charcoal adsorbent traps for collection of volatile organics from incinerators. This study evaluates passivated stainless steel canisters as an alternative to adsorbent traps to eliminate some of the problems associated with adsorbent sampling. Initially the stability of 18 nonpolar, volatile organic compounds was determined in Summa-treated stainless steel canisters with greater than 100 ppmv HCl and saturated with water vapor. All 18 components were stable for a two-week period; however, an interference caused a 10-fold increase in the FID response of trichloroethylene, toluene, and chlorobenzene. No interference of the ECD response was found for any of the 11 compounds detected with the ECD including trichloroethylene. A pilot scale incinerator was sampled using canisters, and the destruction efficiency of 1,1,1-trichloroethane was determined at a concentration of less than 0.5 ppbv while determining 1,1-dichloroethylene, the major product of incomplete combustion, at a concentration of 8000 ppbv from the same sample.