The effect of nicotinamide on gene expression in a traumatic brain injury model.

Microarray-based transcriptional profiling was used to determine the effect of nicotinamide on gene expression in an experimental traumatic brain injury (TBI) model. Ingenuity Pathway Analysis (IPA) was used to evaluate the effect on relevant functional categories and canonical pathways. At 24 h, 72 h, and 7 days, respectively, 70, 58, and 76%, of the differentially expressed genes were up-regulated in the vehicle treated compared to the sham animals. At 24 h post-TBI, there were 150 differentially expressed genes in the nicotinamide treated animals compared to vehicle; the majority (82%) down-regulated. IPA analysis identified a significant effect of nicotinamide on the functional categories of cellular movement, cell-to-cell-signaling, antigen presentation and cellular compromise, function, and maintenance and cell death. The canonical pathways identified were signaling pathways primarily involved with the inflammatory process. At 72 h post-cortical contusion injury, there were 119 differentially expressed genes in the nicotinamide treated animals compared to vehicle; the majority (90%) was up-regulated. IPA analysis identified a significant effect of nicotinamide on cell signaling pathways involving neurotransmitters, neuropeptides, growth factors, and ion channels with little to no effect on inflammatory pathways. At 7 days post-TBI, there were only five differentially expressed genes with nicotinamide treatment compared to vehicle. Overall, the effect of nicotinamide on counteracting the effect of TBI resulted in significantly decreased number of genes differentially expressed by TBI. In conclusion, the mechanism of the effect of nicotinamide on secondary injury pathways involves effects on inflammatory response, signaling pathways, and cell death.

Can changes in angiogenic biomarkers between the first and second trimesters of pregnancy predict development of pre-eclampsia in a low-risk nulliparous patient population?

OBJECTIVE: To determine if change in maternal angiogenic biomarkers between the first and second trimesters predicts pre-eclampsia in low-risk nulliparous women. DESIGN: A nested case-control study of change in maternal plasma soluble Flt-1 (sFlt-1), soluble endoglin (sEng) and placenta growth factor (PlGF). We studied 158 pregnancies complicated by pre-eclampsia and 468 normotensive nonproteinuric controls. SETTING: A multicentre study in 16 academic medical centres in the USA. POPULATION: Low-risk nulliparous women. METHODS: Luminex assays for PlGF, sFlt-1 and sEng performed on maternal EDTA plasma collected at 9-12, 15-18 and 23-26 weeks of gestation. Rate of change of analyte between first and either early or late second trimester was calculated with and without adjustment for baseline clinical characteristics. MAIN OUTCOME MEASURES: Change in PlGF, sFlt-1 and sEng. RESULTS: Rates of change of PlGF, sEng and sFlt-1 between first and either early or late second trimesters were significantly different in women who developed pre-eclampsia, severe pre-eclampsia or early-onset pre-eclampsia compared with women who remained normotensive. Inclusion of clinical characteristics (race, body mass index and blood pressure at entry) increased sensitivity for detecting severe and particularly early-onset pre-eclampsia but not pre-eclampsia overall. Receiver operating characteristics curves for change from first to early second trimester in sEng, PlGF and sFlt-1 with clinical characteristics had areas under the curve of 0.88, 0.84 and 0.86, respectively, and for early-onset pre-eclampsia with sensitivities of 88% (95% CI 64-99), 77% (95% CI 50-93) and 77% (95% CI 50-93) for 80% specificity, respectively. Similar results were seen in the change from first to late second trimester. CONCLUSION: Change in angiogenic biomarkers between first and early second trimester combined with clinical characteristics has strong utility for predicting early-onset pre-eclampsia.

Combination therapies that inhibit cyclooxygenase-2 and leukotriene synthesis prevent disease in murine collagen induced arthritis.

OBJECTIVE AND DESIGN: To determine the effect of combinations of cyclooxygenase (COX) inhibitors and inhibitors of leukotriene (LT) syntheses on collagen induced arthritis (CIA) in mice. METHODS: The CIA model was evaluated for the presence of eicosanoids in the paw tissue. Several selective cyclooxygenase 2 (COX-2) inhibitors or non-selective non-steroidal anti inflammatory drugs (NSAIDs) were evaluated alone or in combination with leukotriene (LT) synthesis inhibitors in the CIA model. RESULTS: Arthritic paw tissue showed increased levels of prostaglandins and leukotrienes in comparison to normal paws. Analysis of mRNA levels indicated the inducible form of the COX-2 enzyme to be the source of prostaglandins. NSAIDs, COX-2 or leukotriene synthesis inhibitors administered alone in CIA decreased severity but had little effect on disease incidence. However, the combination of selective COX-2 inhibitors with leukotriene synthesis inhibitors produced significant decreases in both incidence and severity, suggesting an additive or synergistic effect. This effect was reversible with removal of drug. Little decrease in incidence was observed with the NSAID/5-LO inhibitor combinations. CONCLUSIONS: These results suggest that the induction of the disease in CIA is mediated by products of the COX-2 enzyme and LTB4 production, and that blockade of both pathways is required to prevent CIA.

Nicotinamide treatment induces behavioral recovery when administered up to 4 hours following cortical contusion injury in the rat.

Recent studies have demonstrated nicotinamide (NAM), a soluble B-group vitamin, to be an effective treatment in experimental models of traumatic brain injury (TBI). However, research on this compound has been limited to administration regimens starting shortly after injury. This study was conducted to establish the window of opportunity for NAM administration following controlled cortical impact (CCI) injury to the frontal cortex. Groups of rats were assigned to NAM (50 mg/kg), saline (1 ml/kg), or sham conditions and received contusion injuries or sham procedures. Injections of NAM or saline were administered at 15 min, 4 h, or 8 h post-injury, followed by five boosters at 24 h intervals. Following the last injection, blood was taken for serum NAM analysis. Animals were tested on a variety of tasks to assess somatosensory performance (bilateral tactile adhesive removal and vibrissae-forelimb placement) and cognitive performance (reference and working memory) in the Morris water maze. The results of the serum NAM analysis showed that NAM levels were significantly elevated in treated animals. Behavioral analysis on the tactile removal test showed that all NAM-treated groups facilitated recovery of function compared with saline treatment. On the vibrissae-forelimb placing test all NAM-treated groups also were significantly different from the saline-treated group. However, the acquisition of reference memory was only significantly improved in the 15-min and 4-h groups. In the working memory task both the 15-min and 4-h groups also improved working memory compared with saline treatment. The window of opportunity for NAM treatment is task-dependent and extends to 8 h for the sensorimotor tests but only extends to 4 h post-injury in the cognitive tests. These results suggest that a 50 mg/kg treatment regimen starting at the clinically relevant time point of 4 h may result in attenuated injury severity in the human TBI population.

Rufinamide: Pharmacology, clinical trials, and role in clinical practice.

Rufinamide is a structurally novel compound with anticonvulsant activity that is undergoing evaluation through the European Medicines Agency and the American Food and Drug Administration. Its mechanism of action is thought to be inhibition of sodium-dependent action potentials in neurons, with possible membrane-stabilising effects. Absorption of the drug is significantly enhanced in the fed state. The drug is extensively metabolised by non-CYP450 systems with a half-life of 8-12 h. Most common adverse effects noted are somnolence, fatigue and tremor. Efficacy against partial seizures in adults and adolescents has been demonstrated in three randomised, placebo-controlled trials. Efficacy against seizures of Lennox-Gastaut syndrome, a severe, disabling childhood onset epilepsy syndrome, was shown in a single randomised, placebo-controlled trial. Efficacy against partial onset seizures in children has been suggested in an open-label trial. Should rufinamide become commercially available, reserving the drug as a second- or third-line agent should be considered.

Regulation of oxytocin receptor expression in cultured human myometrial cells by fetal bovine serum and lysophospholipids.

Oxytocin receptor (OTR) expression in human myometrium increases over 150-fold from the beginning of pregnancy to the end. In the present studies, we examined potential mechanisms of OTR up-regulation, using myometrial cells in primary culture from women in late gestation. OTR ligand-binding sites and steady-state mRNA levels were down regulated by serum starvation, and up-regulated by restoration of fetal bovine serum (FBS). Transcriptional activity of the OTR gene was the same with or without FBS treatment, but FBS increased OTR mRNA half-life about 5-fold. Lysophospholipids (lysophosphatidic acid and sphingosine 1-phosphate), which are present in serum, had similar effects as FBS. Lysophospholipid receptor mRNAs of the endothelial differentiation gene (Edg) family (Edgs 1, 3, 4, and 5) were demonstrated in myometrial cells by RT-PCR. These G protein-coupled receptors have been shown to be coupled to G(i/o) and to mediate activation of phosphoinositol 3-phosphate kinase. Indeed, the effects of the lysophospholipids and FBS were completely blocked by pertussis toxin, a G(i/o) inhibitor. Likewise, inhibition of G(i/o) signaling by elevation of intracellular cAMP or inhibition of phosphoinositol 3-phosphate kinase blocked FBS effects on OTR mRNA stability. We do not presently understand the mechanisms of OTR up-regulation in human myometrium in vivo, but the present studies might lead to the description of mRNA-stabilizing factors whose activity can be quantified in tissue samples during pregnancy to elucidate the process of OTR up-regulation.

Risk of recurrent coronary events in relation to use and recent initiation of postmenopausal hormone therapy.

BACKGROUND: The finding from the Heart and Estrogen/Progestin Replacement Study (HERS) of increased coronary risk restricted to the first year after starting postmenopausal hormone therapy raises new questions about the role of hormone therapy in women with coronary heart disease. We assessed the risk of recurrent myocardial infarction or coronary heart disease death associated with the use and recent initiation of hormone therapy in women who survived a first myocardial infarction. METHODS: The setting for this population-based inception cohort study was Group Health Cooperative, a health maintenance organization. We studied 981 postmenopausal women who survived to hospital discharge after their first myocardial infarction between July 1, 1986, and December 31, 1996. We obtained information on hormone use from the Group Health Cooperative computerized pharmacy database and identified recurrent coronary events by medical record review. RESULTS: During median follow-up of 3.5 years, there were 186 recurrent coronary events. There was no difference in the risk of recurrent coronary events between current users of hormone therapy and other women (adjusted relative hazard [RH], 0.96; 95% confidence interval [CI], 0.62-1.50). Relative to the risk in women not currently using hormones, there was a suggestion of increased risk during the first 60 days after starting hormone therapy (RH, 2.16; 95% CI, 0.94-4.95) and reduced risk with current hormone use for longer than 1 year (RH, 0.76; 95% CI, 0.42-1.36). CONCLUSION: These results are consistent with the findings from the HERS, suggesting a transitory increase in coronary risk after starting hormone therapy in women with established coronary heart disease and a decreased risk thereafter.

Antiepileptogenic agents: how close are we?

Epilepsy is a common neurological condition, affecting about 4% of individuals over their lifetime. Epilepsy can be idiopathic, secondary to an underlying genetic abnormality or unknown causes, or acquired. Known potential causes account for about one third of epilepsy. Control of epilepsy has primarily focused on suppressing seizure activity after epilepsy has developed. An intriguing possibility is to control acquired epilepsy by preventing epileptogenesis, the process by which the brain becomes epileptic. Many laboratory models simulate human epilepsy as well as provide a system for studying epileptogenesis. The kindling model involves repeated application of subconvulsive electrical stimulation to the brain, leading to spontaneous seizures. Other models include the cortical or systemic injection of various chemicals. These models suggest that many antiepileptic drugs, from phenobarbital and valproate (valproic acid) to levetiracetam and tiagabine, have antiepileptogenic potential. Some promising other possibilities include N-methyl-D-aspartate (NMDA) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) antagonists as well as the neurotrophins and their receptors. Phenobarbital, phenytoin, valproate, carbamazepine and, to a very limited extent, diazepam have been evaluated in clinical trials to test whether they actually prevent epileptogenesis in humans. Results have been very disappointing. Meta-analyses of 12 different drug-condition combinations show none with significantly lower unprovoked seizure rates among those receiving the active drug. In 4 of the 12, the observed rate was actually slightly higher among treated individuals. None of the newer drugs have been evaluated in antiepileptogenesis trials. Until some drugs demonstrate a clear antiepileptogenic effect in clinical trials, the best course to reduce the incidence of epilepsy is primary prevention of the risk-increasing events--for example, wearing helmets, using seat belts, or decreasing the risk of stroke by reducing smoking.

Lack of an effect of valproate concentration on lamotrigine pharmacokinetics in developmentally disabled patients with epilepsy.

PURPOSE: to describe the population pharmacokinetics of lamotrigine (LTG) in developmentally disabled (DD) patients with epilepsy and (2) to determine if there is an effect of valproate (VPA) concentration on the extent of the pharmacokinetic interaction between VPA and LTG. METHOD: a NONMEM population analysis of steady-state LTG serum concentrations was conducted in patients receiving LTG either as mono or polytherapy with either an enzyme inducer (IND)-carbamazepine (CBZ), phenytoin (PHT), phenobarbital (PB) or an inhibitor (VPA). RESULTS: sixty-two patients (33.6+/-11.3 years, 47+/-9.9 kg) receiving LTG monotherapy (n=19) or polytherapy with VPA (n=15), inducer(s) (n=32) or both (n=5) were evaluated. LTG dose of 369+/-236 mg per day (8.1+/-5.9 mg/kg per day) achieved LTG plasma concentrations of 6.8+/-3.3 microg/ml. The observed LTG monotherapy, LTG+IND, and LTG+VPA oral clearance (Cl/F) were 0. 69+/-0.2, 1.60+/-0.65 and 0.2+/-0.05 ml/kg per min, respectively. The final LTG Cl/F model was dependent on body weight, concomitant VPA, and either single or multiple inducers. Including the serum concentrations of CBZ, PHT, or VPA in the model, did not significantly improve estimates of Cl/F. CONCLUSION: LTG Cl/F in DD patients is similar to literature values for ambulatory adult patients; however, low weight adult patients have higher elimination rates, as well as an increased response to enzyme induction. VPA inhibition of LTG Cl/F is maximal within the usually accepted therapeutic range for VPA.

Incidence of intravenous site reactions in neurotrauma patients receiving valproate or phenytoin.

OBJECTIVE: To determine the incidence of intravenous site reactions to phenytoin and valproate in a large population of patients with neurotrauma. DESIGN: Retrospective chart review of two double-blind, randomized clinical trials evaluating the use of antiepileptic drugs to prevent posttraumatic seizures in patients with neurotrauma: phenytoin versus placebo (n = 390), and valproate versus phenytoin with placebo (n = 385). Information collected from the charts included the number, type, and location of intravenous lines and intravenous site events. SETTING: Tertiary care trauma and university teaching hospital. MAIN RESULTS: Intravenous site reactions occurred in 18% and 25% of patients receiving valproate or phenytoin, respectively, with the majority of events (70%) occurring in the first intravenous site. Patients received the neurosurgery study drug (NSSD) by either central or peripheral lines; all intravenous site reactions occurred in peripheral administration sites. When patients who received the drug by central line during the course of therapy were excluded, the estimated incidence of site reactions was 21% and 30% for valproate and phenytoin, respectively (p = 0.056). The time to the first event was shorter with phenytoin compared with valproate (2.0 +/- 1.3 vs. 3.0 +/- 1.9 d; p = 0.009). Fewer adverse events were noted with phenytoin in the phenytoin-without-valproate study than in the phenytoin-with-valproate study, with 4.3% and 8.2% of intravenous site events recorded in patients receiving placebo or phenytoin, respectively. There was no significant difference in the number of intravenous lines per patient used during NSSD drug infusion for phenytoin versus placebo or phenytoin versus valproate. CONCLUSIONS: Both intravenous phenytoin and valproate resulted in intravenous site reactions, with the loading doses responsible for the majority of the events.

St John's Wort: effect on CYP3A4 activity.

BACKGROUND: St John's Wort is a widely used herbal product. Information regarding its potential for drug interactions is required for responsible treatment of patients using St John's Wort. CYP3A4 is a metabolic enzyme implicated in most clinically significant drug-drug interactions. OBJECTIVE: To determine the in vivo effect of reagent-grade St John's Wort extract on CYP3A4 activity through evaluation of urinary 6-beta-hydroxycortisol/cortisol ratios. METHODS: Thirteen subjects ranging in age from 18 to 25 years participated in this unblinded, multiple-dose, single-treatment before-after trial conducted in a university-based pharmacokinetics and biopharmaceutics laboratory. Each subject ingested a 300-mg tablet of reagent-grade St John's Wort extract standardized to 0.3% hypericin three times a day for 14 days. Baseline and posttreatment CYP3A4 activity was assessed with the urinary 6-beta-hydroxycortisol/cortisol ratio after a 24-hour urine collection. RESULTS: The mean +/- SD urinary 6-beta-hydroxycortisol/cortisol ratio significantly increased (P = .003) from a baseline value of 7.1 +/- 4.5 to 13 +/- 4.9. The mean +/- SD percentage increase was 114% +/- 95%, with a range from -25% to 259%. All but one subject had an increase in the ratio. CONCLUSIONS: Treatment with St John's Wort for 14 days resulted in significant increases in the urinary 6-beta-hydroxycortisol/cortisol ratio. This finding suggests that St John's Wort is an inducer of CYP3A4.

Upregulation of COX-2 during cardiac allograft rejection.

BACKGROUND: The hypothesis that cyclooxygenase-2 (COX-2) is involved in the myocardial inflammatory response during cardiac allograft rejection was investigated using a rat heterotopic abdominal cardiac transplantation model. METHODS AND RESULTS: COX-2 mRNA and protein in the myocardium of rejecting cardiac allografts were significantly elevated 3 to 5 days after transplantation compared with syngeneic controls (n=3, P<0.05). COX-2 upregulation paralleled in time and extent the upregulation of iNOS mRNA, protein, and enzyme activity in this model. COX-2 immunostaining was prominent in macrophages infiltrating the rejecting allografts and in damaged cardiac myocytes. Prostaglandin (PG) levels in rejecting allografts were also higher than in native hearts. Because NO has been reported to modulate PG synthesis by COX-2, additional transplants were performed using animals treated with a selective COX-2 inhibitor (SC-58125) and a selective inhibitor of the inducible nitric oxide synthase (iNOS) N-aminomethyl-L-lysine. At posttransplant day 5, inhibitor administration resulted in a significant reduction of COX-2 mRNA expression (3764+/-337 versus 5110+/-141 arbitrary units, n=3, P<0.05) and iNOS enzymatic activity (1.7+/-0.4 versus 22.8+/-14. 4 nmol/mg protein, n=3, P<0.01) compared with vehicle-treated allogeneic transplants. Allograft survival in treated animals was increased modestly from 5.4 to 6.4 days (P<0.05). However, apoptosis of cardiac myocytes (TUNNEL method) was only marginally reduced relative to vehicle controls in treated graft recipients. The intensity of allograft rejection was also similar in the treated and untreated allografts. CONCLUSIONS: The data indicates that COX-2 expression is enhanced in parallel with iNOS in the myocardium during cardiac allograft rejection.

Neuropsychological effects of valproate in traumatic brain injury: a randomized trial.

OBJECTIVES: To examine the neuropsychological side effects of valproate (VPA) given to prevent posttraumatic seizures. METHODS: In a randomized, double-masked, parallel group clinical trial, we compared the seizure prevention and neuropsychological effects of 1 or 6 months of VPA to 1 week of phenytoin. We studied 279 adult subjects who were randomized within 24 hours of injury and examined with a battery of neuropsychological measures at 1, 6, and 12 months after injury. We examined drug effects cross-sectionally at 1, 6, and 12 months and longitudinally by examining differential change from 1 to 6 months and from 6 to 12 months as a function of protocol-dictated changes in treatment. RESULTS: No significant adverse or beneficial neuropsychological effects of VPA were detected. CONCLUSIONS: Valproate (VPA) appears to have a benign neuropsychological side effects profile, making it a cognitively safe antiepileptic drug to use for controlling established seizures or stabilizing mood. However, based on this study, VPA should not be used for prophylaxis of posttraumatic seizures because it does not prevent posttraumatic seizures, there was a trend toward more deaths in the VPA groups, and it did not have positive effects on cognition.

Impact of taking antiepileptic drugs at school in a group of children and adolescents.

The impact of epilepsy on the quality of life can be significant. Peer acceptance is important for the social adjustment of children. Even children with controlled seizures may appear different from their peers if they are required to leave the classroom to take antiepileptic drugs. The objective of this pilot study was to determine if there is a measurable effect on peer relationships in children having to leave the classroom or recess time to take antiepileptic medications in a school setting. Results of surveys mailed or distributed by a pharmacist were obtained from 47 children, aged 6 to 18 years. Children who reported poor seizure control were significantly more likely to have trouble making friends compared with those with seizures controlled (70% vs 27%, P = 0.02). Even though the majority reported good seizure control (7/8), the children who left the classroom to take medications reported that they had significantly more trouble making friends than those who did not leave the classroom (63% vs 21%, P = 0.03). Therefore, the effect of taking medication at school may be associated with a significant decrease in social and peer relationships, even in children with self-reported good seizure control.

Age-dependent differences in flurothyl seizure sensitivity in mice treated with a ketogenic diet.

Despite strong clinical data confirming the anticonvulsant efficacy of a ketogenic diet (KGD) in pediatric patients, corroborative experimental data in young animals are limited. In the present study, the effects of a KGD on flurothyl seizure susceptibility were examined in normal juvenile mice after a dietary duration of 3, 7, or 12 days, and in adult mice for 15 days. In all groups of KGD-treated mice, blood beta-hydroxybutyrate levels were significantly elevated over those measured in controls. The present KGD was anticonvulsant (i.e. delayed onset) against the first (clonic) flurothyl-induced seizure for juvenile mice treated for either 7 or 12 days, but not for juvenile mice and adult mice fed the diet for 3 and 15 days, respectively. While this KGD was not anticonvulsant against the second (tonic extension) seizure induced by flurothyl in any of the juvenile groups, it significantly delayed tonic extension in the adult group. In addition, juvenile mice fed a KGD exhibited a lower mortality rate following flurothyl-induced seizures compared to mice fed a standard diet. In our discussion of animal models of the KGD, we highlight the need to understand better the impact of important variables such as dietary composition, genetic background, and mode of seizure induction in the study of the KGD.

Valproate therapy for prevention of posttraumatic seizures: a randomized trial.

OBJECT: Seizures frequently accompany moderate to severe traumatic brain injury. Phenytoin and carbamazepine are effective in preventing early, but not late, posttraumatic seizures. In this study the authors compare the safety and effectiveness of valproate with those of short-term phenytoin for prevention of seizures following traumatic brain injury. METHODS: The study was a randomized, double-blind, single-center, parallel-group clinical trial. Treatment began within 24 hours of injury. One hundred thirty-two patients at high risk for seizures were assigned to receive a 1-week course of phenytoin, 120 were assigned to receive a 1-month course of valproate, and 127 were assigned to receive a 6-month course of valproate. The cases were followed for up to 2 years. The rates of early seizures were low and similar when using either valproate or phenytoin (1.5% in the phenytoin treatment group and 4.5% in the valproate arms of the study; p = 0.14, relative risk [RR] = 2.9, 95% confidence interval [CI] 0.7-13.3). The rates of late seizures did not differ among treatment groups (15% in patients receiving the 1-week course of phenytoin, 16% in patients receiving the 1-month course of valproate, and 24% in those receiving the 6-month course of valproate; p = 0.19, RR = 1.4, 95% CI 0.8-2.4). The rates of mortality were not significantly different between treatment groups, but there was a trend toward a higher mortality rate in patients treated with valproate (7.2% in patients receiving phenytoin and 13.4% in those receiving valproate; p = 0.07, RR = 2.0, 95% CI 0.9-4.1). The incidence of serious adverse events, including coagulation problems and liver abnormalities, was similar in phenytoin- and valproate-treated patients. CONCLUSIONS: Valproate therapy shows no benefit over short-term phenytoin therapy for prevention of early seizures and neither treatment prevents late seizures. There was a trend toward a higher mortality rate among valproate-treated patients. The lack of additional benefit and the potentially higher mortality rate suggest that valproate should not be routinely used for the prevention of posttraumatic seizures.

Differences in the urinary excretion of 6-beta-hydroxycortisol/cortisol between Asian and Caucasian women.

The urinary ratio of 6-beta-hydroxycortisol/cortisol has been used as a noninvasive probe for human cytochrome P450 3A4 isoforms (CYP3A4). Ethnic-related differences in the ratio have not been evaluated. The aim of this study was to determine if there are differences in the ratio between Asian and Caucasian women over a menstrual cycle. First-morning urine samples were collected every other day starting from the second day of menstruation for a complete menstrual cycle from 15 Asians and 16 Caucasian women who were 18 to 40 years old, healthy, nonsmoking, and alcohol and drug free, including oral contraceptives. Urine concentrations of 6-beta-hydroxycortisol and cortisol were measured by high-pressure liquid chromatography (HPLC). For statistical analysis, three phases of the menstrual cycle were evaluated: menstruation (days 1-4), follicular or postmenstruation (days 6-10), and the luteal phase (days 21-24) based on the average menstrual cycle (28 days). Statistical analysis was performed by an independent sample t-test using the Bonferroni correction for repeated measures. Large intersubject and intrasubject variations of the 6-beta-hydroxycortisol/cortisol ratios were observed during the menstrual cycles in both ethnic groups. Asian women had a statistically significant lower ratio than Caucasian women did for all three phases of the menstrual cycle: 2.2 +/- 1.1 versus 5.1 +/- 3.5, 2.1 +/- 1.1 versus 6.0 +/- 4.9, and 2.8 +/- 1.6 versus 5.6 +/- 3.0 for the menstruation, follicular, and luteal phases, respectively. The two- to threefold lower 6-beta-hydroxycortisol/cortisol ratios in Asian women suggest that Asian women may have a lower CYP3A activity compared with Caucasian women. Differences in ethnicity may mask potential gender-related effects if ethnic background is not evaluated as a contributing factor.

Electronic fetal monitoring. Are we meeting documentation standards?

OBJECTIVE: To test whether fetal heart rate documentation requirements for high-risk pregnancies are too stringent to achieve compliance, especially during the second stage of labor. STUDY DESIGN: Random retrospective chart and monitor strip review of deliveries occurring one year earlier were reviewed. Thirty-four low-risk and 34 high-risk pregnancies were selected and assessed for compliance with nationally accepted documentation guidelines. RESULTS: All monitor strips and charts were successfully retrieved from medical records. Charted documentation of the strips met national requirements in the active phase of the first stage of labor in 97% of cases, as did documentation during the second stage. For high-risk pregnancies, compliance during the active phase of the first stage of labor was 65% as compared to 35% in the second stage. All infants had normal five-minute Apgar scores, and none had umbilical arterial acidemia. CONCLUSION: Given current resources, we cannot reliably meet established documentation standards for high-risk pregnancies. Such overly stringent documentation standards pose a significant risk in cases going to litigation. A standard should be developed that is based on outcome data.

Cytochrome P450 3A4 activity in premenopausal and postmenopausal women, based on 6-beta-hydroxycortisol:cortisol ratios.

STUDY OBJECTIVE: To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-beta-hydroxycortisol:cortisol ratio. DESIGN: Prospective study SUBJECTS: Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity INTERVENTIONS: Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days. MEASUREMENTS AND MAIN RESULTS: Mean weekly 6-beta-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios. CONCLUSION: Cytochrome P450 3A4 activity as measured by 6-beta-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause.

Effect of troglitazone on urinary excretion of 6beta-hydroxycortisol.

Coadministration of troglitazone reduces the plasma concentrations of terfenadine and ethinyl estradiol. Because these drugs are metabolized at least in part by cytochrome P450 3A (CYP3A), it is possible that troglitazone induces CYP3A activity, thereby reducing plasma concentrations of these agents. Known inducers of CYP3A, such as rifampin, phenytoin, carbamazepine, and phenobarbital, increase the urinary excretion of 6beta-hydroxycortisol and the ratio of 6beta-hydroxycortisol to cortisol. This evaluation examined the effect of troglitazone on urinary excretion of 6beta-hydroxycortisol and the ratio of 6beta-hydroxycortisol to cortisol as a marker for CYP3A induction. Urine samples were collected from 11 subjects who completed a study evaluating the effect of multiple-dose administration of troglitazone 400 mg once daily (days 11-20) on the steady-state pharmacokinetics of digoxin (0.25 mg daily on days 1-20). A single urine sample was collected at baseline on day 1, and 24-hour urine samples were collected on days 10 and 20. Mean +/- standard deviation 24-hour excretion rate of cortisol was unchanged, whereas that of 6beta-hydroxycortisol increased during troglitazone administration. The ratio of 24-hour urinary 6beta-hydroxycortisol to cortisol excretion increased from 7.4 +/- 2.7 on day 10 to 16.1 +/- 6.2 on day 20. The ratio observed on day 10 was similar to that obtained at baseline. These results are consistent with the hypothesis that troglitazone induces CYP3A activity.