An accessible pharmacodynamic transcriptional biomarker for notch target engagement.

γ-Secretase mediates amyloid production in Alzheimer's disease (AD) and oncogenic activity of Notch. γ-Secretase inhibitors (GSIs) are thus of interest for AD and oncology. A peripheral biomarker of Notch activity would aid determination of the therapeutic window and dosing regimen for GSIs, given toxicities associated with chronic Notch inhibition. This study examined the effects of GSI MK-0752 on blood and hair follicle transcriptomes in healthy volunteers. The effects of a structurally diverse GSI on rhesus blood and hair follicles were also compared. Significant dose-related effects of MK-0752 on transcription were observed in hair follicles, but not blood. The GSI biomarker identified in follicles exhibited 100% accuracy in a clinical test cohort, and was regulated in rhesus by a structurally diverse GSI. This study identified a translatable, accessible pharmacodynamic biomarker of GSI target engagement and provides proof of concept of hair follicle RNA as a translatable biomarker source.

BRAF mutant gastrointestinal stromal tumor: first report of regression with BRAF inhibitor dabrafenib (GSK2118436) and whole exomic sequencing for analysis of acquired resistance.

Activating oncogenic mutations of BRAF have been described in patients with gastrointestinal stromal tumor (GIST), but treatment of GIST with BRAF inhibitors and mechanisms of mediating the emergence of resistance in GIST have not been reported. Dabrafenib is a potent ATP-competitive inhibitor of BRAF kinase and is highly selective for mutant BRAF in kinase panel screening, cell lines, and xenografts. We report prolonged antitumor activity in the first patient with V600E BRAF-mutated GIST who was treated with a BRAF inhibitor. Whole exome sequencing performed in tumor tissue obtained at the time of progressive disease demonstrated a somatic gain-of-function PIK3CA mutation (H1047R) as well as a CDKN2A aberration, which may have contributed to eventual resistance to treatment.

Identification and functional characterization of thromboxane A2 receptors in Schwann cells.

Previous reports have demonstrated the presence of functional thromboxane A2 (TP) receptors in astrocytes and oligodendrocytes. In these experiments, the presence and function of TP receptors in primary rat Schwann cells (rSC) and a neurofibrosarcoma-derived human Schwann cell line (T265) was investigated. Immunocytochemical and immunoblot analyses using polyclonal anti-TP receptor antibodies demonstrate that both cell types express TP receptors. Treatment with the stable thromboxane A2 mimetic U46619 (10 microM) did not stimulate intracellular calcium mobilization in rSC, whereas T265 cells demonstrated a calcium response that was inhibited by prior treatment with TP receptor antagonists. U46619 also stimulated CREB phosphorylation on Ser133 in T265 cells and, to a lesser extent, in rSC. To identify potential mechanisms of CREB phosphorylation in rSC, we monitored intracellular cAMP levels following U46619 stimulation. Elevated levels of cAMP were detected in both rSC (20-fold) and T265 (15-fold) cells. These results demonstrate that TP receptor activation specifically stimulates CREB phosphorylation in T265 cells, possibly by a calcium- and/or cAMP-dependent mechanism. In contrast, TP receptor activation in rSC stimulates increases in cAMP and CREB phosphorylation but does not elicit changes in intracellular calcium.

The identification and characterization of oligodendrocyte thromboxane A2 receptors.

The presence of functional thromboxane A2 receptors in neonatal rat oligodendrocytes and human oligodendroglioma cells was investigated using immunocytochemistry, ligand affinity chromatography, radioligand binding analysis, immunoblot analysis, and calcium mobilization studies. Immunocytochemical studies revealed the presence of receptor protein on both oligodendrocytes and human oligodendroglioma cells. Ligand affinity chromatography allowed for the purification of a protein with an electrophoretic mobility (55 kDa) indistinguishable from human platelet thromboxane A2 receptors. This affinity purified protein was immunoreactive against a polyclonal anti-thromboxane A2 receptor antibody. Intact human oligodendroglioma cells specifically bound [3H]SQ29,548 with a KD of 4 nM and were found to have approximately 3500 binding sites per cell. Human oligodendroglioma cells also demonstrated calcium mobilization in response to receptor activation with U46619. These results demonstrate the presence of a functional thromboxane A2 receptor in oligodendrocytes and are consistent with previous observations indicating a high density of thromboxane A2 receptors in myelinated brain and spinal cord fiber tracts.

Postcesarean analgesia with both epidural morphine and intravenous patient-controlled analgesia: neurobehavioral outcomes among nursing neonates.

UNLABELLED: Among nursing parturients after cesarean delivery, intravenous patient-controlled analgesia (PCA) with meperidine is associated with significantly more neonatal neurobehavioral depression than PCA with morphine. A single dose of epidural morphine (4 mg) decreases postcesarean opioid analgesic requirements and may reduce or prevent neonatal neurobehavioral depression associated with PCA meperidine. Prospectively, 102 term parturients underwent cesarean delivery with epidural anesthesia, 2% lidocaine and epinephrine 1:200,000. After umbilical cord clamping, each patient received epidural morphine 4 mg and was randomly allocated to receive either PCA meperidine or PCA morphine. Initial neonatal characteristics, included gestational age, Apgar scores, weight, and umbilical cord gas partial pressures. Brazelton Neonatal Behavioral Assessment Scale (NBAS) examinations were performed on each of the first 4 days of life. Nursing infants (n = 47) were grouped according to maternal PCA opioid in breast milk (meperidine [n = 24] or morphine [n = 23]); bottle-fed infants (n = 56) served as the control group. The three infant groups were equivalent with respect to initial characteristics and NBAS scores on the first 2 days of life. On the third day of life, infants in the morphine group were significantly more alert and oriented to animate human cues compared with infants in the meperidine or control group. On the fourth day of life, infants in the morphine group remained significantly more alert and oriented to animate human auditory cues than infants in the meperidine group. Average PCA opioid consumption through 48 h postpartum was equivalent (0.54 mg/kg morphine and 4.7 mg/kg meperidine); however, even with these small doses, meperidine was associated with significantly poorer neonatal alertness and orientation than morphine. Morphine is the PCA opioid of choice for postcesarean analgesia among nursing parturients. IMPLICATIONS: Among nursing parturients after cesarean delivery, intravenous patient-controlled analgesia with meperidine is associated with more neonatal neurobehavioral depression than patient-controlled analgesia with morphine. In this study, we found that nursing infants exposed to morphine were more alert and oriented to animate human cues than those exposed to meperidine.

Toxicology screening in adolescent trauma.

We sought to define the prevalence of positive drug screens in adolescent victims of major trauma. The records of 125 consecutive adolescent patients presenting with major trauma to an inner-city trauma center during the last nine months of 1990 were reviewed. Eighty-five (68%) received urine toxicology screens for alcohol and illicit drugs. Twenty-one (25%) of screened patients had a positive urine drug screen. The most commonly detected drugs were alcohol, cocaine, and opiates. Gender, race, mechanism of injury, mental status at presentation, injury severity score, and revised trauma score were not associated with a positive drug screen. We conclude that: 1) 25% of screened adolescent victims of major trauma seen at an inner-city trauma center had positive urine toxicology screens for alcohol or illicit drugs. 2) As none of the study variables was associated with a positive drug screen, selective drug screening cannot be supported.

Measuring the saving attributable to an antibiotic prescribing policy.

An analytical framework is suggested for the economic evaluation of policies to improve the management of hospital infection. Consideration of the costs and benefits to be expected from improved policies implies the existence of an optimal infection rate which is higher than the minimum attainable. It follows that hospitals can and probably do spend too much on infection control in, at least, some areas. This optimal approach is not operational at present but its data requirements might be thought of as an agenda for future research. In the meantime, progress in infection control economics depends on a piecemeal approach. An example is given in the estimation of the cost savings attributable to an improved antibiotic prescribing policy at the Royal Liverpool Hospital.