The molecular genetics of therapeutic resistance in malignant astrocytomas

The adverse prognosis associated with malignant astrocytomas (MA) is due in part to the development of resistance by the tumor to chemo- and radiotherapy-induced cytotoxic damage. The mechanisms of resistance are poorly understood but function at the level of the endothelial cell, the blood-brain barrier and the neoplastic cell itself. The classic examples of drug resistance proteins, such as the p-glycoprotein/multidrug resistance protein 1, have been identified within MA biopsy specimens. However, it is questionable to what degree, if at all, these proteins contribute directly to the evolution and prognosis of the MA. Surprisingly, there are specific genes, not traditionally associated with resistance, which appear increasingly relevant to both tumor progression and insensitivity to cytotoxic damage. These genes are involved in cell cycle regulation, and include the retinoblastoma susceptibility gene (Rb), the tumor suppressor gene p53, as well as those encoding the cyclins, their kinases and inhibitors. The interaction between the products of these genes and intratumoral environmental factors appears to involve a dynamic and prognostically adverse selection process. It is from this perspective that the mechanism(s) of hypoxic-ischaemic selection for resistance and its therapeutic repercussions will be analyzed.

Pharmacotherapy of malignant astrocytomas of children and adults: current strategies and future trends

This article reviews the conceptual progression in the pharmacological therapy of malignant astrocytoma (MA) over the past decade, and its future trends. It is a selective rather than an exhaustive inventory of literature citations. The experience of the Brain Tumour Cooperative Group (BTCG) and earlier phase III trials are summarised to place subsequent phase II and I studies of single and combination agent chemotherapy in perspective. The BTCG experience of the 1970s to 1980s may be summarised to indicate that external beam radiotherapy (EBRT) is therapeutic, although not curative, and not further improved upon by altering fractionation schedules, or the addition of radioenhancers. Whole brain and reduced whole brain EBRT with focal boost were comparable regimens. Nitrosourea-based, adjuvant chemotherapy provided a modest improvement in survival among adult patients, which was comparable with that of other single drugs or multidrug regimes. The multiagent schedules, however, had a correspondingly higher toxicity rate. Intra-arterial administration was associated with significant risk, which conferred no therapeutic advantage. The trend of the past decade has been towards multiagent chemotherapy although its benefit cannot be predicted from the classic prognostic factors. Published experience with investigational trials utilising myeloablative chemotherapy with autologous bone marrow or peripheral blood stem cell haemopoietic support, drug delivery enhancement methods and radiosensitisers is critically reviewed. None of these approaches have achieved wide-spread acceptance in the treatment of adult patients with MA. Greater attention is placed on recent 'chemoradiotherapy' trials, which attempt to integrate and maximise the cytoreductive potential of both modalities. This approach holds promise as an effective means to delay or overcome the evolution of tumour resistance, which is probably one of the dominant determinants of prognosis. However, the efficacy of this approach remains unproven. New chemotherapeutic agents as well as biological response modifiers, protein kinase inhibitors, angiogenesis inhibitors and gene therapy are also discussed; their role in the therapeutic armamentarium has not been defined.

Identification of halogen atoms in scanning tunneling microscopy images of substituted phenyl octadecyl ethers

A homologous series of para-substituted phenyl octadecyl ethers (X-POEs, where X = H, Cl, Br, I) was prepared using the Williamson ether synthesis and characterized by 1H NMR and GC/MS. Scanning tunneling microscopy images acquired from these ethers revealed a bias-dependent contrast corresponding to electron density contours of various X-POE molecular orbitals. Images reflecting the electron density contour of the highest occupied molecular orbital exhibited four bright spots--one for the halogen atom, two representing the pair of lobes of the phenyl ring, and one for the oxygen/alpha-carbon atoms. For each X-POE, the intensities (Zmax) of the spots for the halogen atom and the lobe of the phenyl ring closest to the halogen were measured and their ratio was calculated (Cl-POE 0.49 +/- 0.06; Br-POE 0.59 +/- 0.06; I-POE 0.75 +/- 0.07). Analysis of variance at the 95% confidence level revealed that the intensity ratios were consistent from molecule to molecule, image to image, and day to day. According to the Student t-test, the average Zmax ratios for Cl-POE, Br-POE, and I-POE are different at the 95% confidence level. In addition, they follow a trend that corresponds favorably with that of the atomic radii of the halogens. The probability of classifying a single X-POE molecule as Cl-POE, Br-POE, or I-POE is variable and depends on the magnitude of the Zmax ratio.

Saturable transport of the neurokinin-1 non-peptide antagonist LY303870 across the rat blood-brain barrier after intravenous administration

LY303870 (LY) is a non-peptide neurokinin-1 receptor antagonist that has effects on the brain after peripheral administration. We determined whether LY given by intravenous (iv) injection can cross the blood-brain barrier (BBB). Multiple-time regression analysis showed the unidirectional influx rate (Ki) from blood to brain for LY labeled with tritium to be 6.41+/-0.85 microl/g-min and influx was inhibited by unlabeled LY. HPLC and mass spectrometry showed LY was stable in blood and brain. LY reached a brain/serum ratio of 190+/-12 microl/g with about 0.07% of the injected dose entering each gram of brain. These results show that LY is transported across the BBB from serum into brain by a saturable system.

Succinylcholine pretreatment using gallamine or mivacurium during rapid sequence induction in children: a randomized, controlled study

STUDY OBJECTIVE

To determine if pretreatment with either gallamine or mivacurium before succinylcholine in children is associated with reduction in fasciculations; postoperative myalgias; or serum levels of potassium, creatinine phosphokinase (CPK), and myoglobin.

DESIGN

Prospective, randomized, double-blinded study.

SETTING

Operating room at a children's hospital.

PATIENTS

45 ASA physical status IE children, aged 3 to 15 years, scheduled for emergency surgery.

INTERVENTIONS

The children received either normal saline 0.5 mL, mivacurium chloride 0.03 mg. kg(-1), or gallamine triethiodide 0.04 mg. kg(-1)2 minutes prior to rapid sequence induction (RSI) using thiopental sodium 5 mg. kg(-1), fentanyl 2 microg. kg(-1), and succinylcholine 2 mg. kg(-1).

MEASUREMENTS

Serum potassium concentration (0, 3, 5, 7.5, and 15 min), myoglobin concentration (5 and 15 min), and CPK concentration (0 min and 24 hr). Fasciculation and myalgia were rated on a 0 to 3 score.

MAIN RESULTS

There was no difference between groups for fasciculation (p = 0.87) or myalgia score (p = 0.52). The mivacurium group had significantly less increase in potassium at 5 minutes (0.45 vs. 0.0, p = 0.01), myoglobin at 5 minutes (56 vs. 2, p < 0.001), myoglobin at 15 minutes (128 vs. 2.5, p < 0.001), and CPK at 24 hours (399 vs. 138, p < 0.001) following succinylcholine when compared with normal saline. Additionally, we found a significant level of association (p < 0.001) between fasciculation and myoglobin levels and fasciculation and CPK levels (p < 0.001). Gallamine was not effective in reducing the increase of potassium, myoglobin, or CPK. However, the dose of gallamine used for pretreatment was 13 times less than the dose of mivacurium.

CONCLUSIONS

Administration of mivacurium 0.03 mg. kg(-1) intravenously 2 minutes before administration of succinylcholine 2 mg. kg(-1) in children is effective in reducing the increase in serum potassium at 5 minutes, the increase in myoglobin at 5 minutes and 15 minutes, and the increase in CPK at 24 hours.

Corticotropin-releasing factor (CRF) or CRF binding-protein ligand inhibitor administration suppresses food intake in mice and elevates body temperature in rats

Corticotropin-releasing factor (CRF) receptor agonist and CRF binding-protein (CRF-BP) ligand inhibitor peptides both activate CRF systems but exert very distinct functional profiles in animal models of arousal, energy balance and emotionality. The present studies were designed to extend the dissimilar efficacy profiles of central administration of a CRF agonist, r/h CRF(1-41), versus a CRF-BP ligand inhibitor, r/h CRF(6-33), into mouse and rat models of energy balance in order to further explore in vivo efficacy of these ligands in two separate animal species. In CD-1 mice, food intake was significantly attenuated 3 h after acute administration of CRF(1-41) (0.007-0.2 nmol), but not CRF(6-33). In obese Ob/Ob mice, both CRF(1-41) (0.007-0.2 nmol) and CRF(6-33) (0.02-2.3 nmol) significantly attenuated basal feeding over 3 h following acute peptide administration. In rats, CRF(1-41) (1 nmol) and CRF(6-33) (1.5-7.7 nmol) infusion significantly increased rectal temperature. In studies employing a telemetry apparatus, core temperature was also increased by CRF(1-41) (1 nmol) and CRF(6-33) (1.5 nmol), whereas only CRF(1-41) increased locomotor activity and heart rate. These results suggest that CRF receptor agonist administration is capable of producing a global profile of negative energy balance by reducing food intake in mice and increasing energy expenditure in rats. In contrast, CRF-BP ligand inhibitor administration appears to suppress food intake in a mouse strain selective manner and to elevate rectal and core temperature in rats without accompanying cardiovascular activation.

Electrocardiographic prediction of abnormal genotype in congenital long QT syndrome: experience in 101 related family members

INTRODUCTION

Previous studies showed that diagnosing congenital long QT syndrome (LQTS) is difficult due to variable penetrance and genetic heterogeneity, especially when subjects from multiple families with diverse mutations are combined. We hypothesized that a combination of clinical and ECG techniques could identify gene carriers within a single family with congenital LQTS.

METHODS AND RESULTS

One hundred one genotyped members of a family with LQTS, including 26 carriers of a HERG mutation, underwent history and ECG analysis. Forty-eight family members also underwent exercise testing with QT and T wave alternans (TWA) analysis and 24-hour Holter monitoring with QT and heart rate variability analysis. A logistic regression model, which included age, gender, QTc, and QTc by age, provided the best prediction of gene carrier status, although there was substantial overlap (78%) of QTc among subjects with and without the mutation. QTc was not helpful as a discriminator in children < or = 13 years. TWA (observed infrequently) did not add significantly to the model's ability to predict abnormal genotype.

CONCLUSION

Even in this homogeneous LQTS population, the phenotype was so variable that clinical and detailed ECG analyses did not permit an accurate diagnosis of gene carrier status, especially in children. Sustained microvolt TWA was a specific (100%) but insensitive (18%) marker for LQTS. Its ability to predict risk of arrhythmia in this population remains to be determined. Genetic testing serves an essential role in screening for carriers of LQTS.

Analyses of cross species polymerase chain reaction products to infer the ancestral state of human polymorphisms

In numerous population genetic and disease association studies decisions about the ancestry of polymorphic alleles are often made based on the relative frequency of the alleles in the extant populations with the most frequent allele being deemed as ancestral. However, the frequency of an allele in a population is generally not a perfect indicator of its ancestral status. A more accurate method to assess ancestral/derived status of polymorphic alleles involves identification of shared alleles between species. We used this strategy to examine genomic regions homologous to several human polymorphisms in four species of non-human primates. Cross species polymerase chain reaction (CS-PCR), with primers designed from human sequence, was used to investigate regions of interest. Nineteen polymorphisms at six loci (DRD2, HOXB@, PAH, D4S10, RBP3, and RET) were examined either by restriction fragment length analysis of PCR products (PCR-RFLP) or by direct sequencing. At seventeen of the eighteen PCR-RFLPs, non-human primates were monomorphic and identical to each other for either lack of restriction enzyme site or presence of the site. Thus, at these seventeen polymorphic sites the shared alleles are most likely to be the ancestral ones in humans. In several cases we have used sequence data to further demonstrate that the nucleotide at the site of the polymorphism is conserved between species confirming the hypothesis of a single ancestral allele. However, not all human alleles can be simply resolved into ancestral and derived; sequence data from one PCR-RFLP (in an intron of the PAH locus) and a single strand conformational polymorphism (SSCP) in the 3' untranslated region (UTR) of the DRD2 gene illustrate this point.

New perspectives and evidence on political communication and campaign effects

We review recent empirical evidence that shows political campaigns are more potent than widely believed, focusing on the conceptual and methodological advances that have produced these findings. Conceptually, a broader definition of effects--that includes learning and agenda-control, as well as vote choice--characterizes contemporary research. This research also features two kinds of interactive models that are more complex than the traditional hypodermic (message-based) approach. The resonance model considers the relationship between message content and receivers' predispositions, while the strategic model highlights the interactions between competing messages. Finally, we attribute the emergence of stronger evidence in favor of campaign effects to the use of new methodologies including experimentation and content analysis, as well as the more sophisticated use of sample surveys.

New perspectives and evidence on political communication and campaign effects

We review recent empirical evidence that shows political campaigns are more potent than widely believed, focusing on the conceptual and methodological advances that have produced these findings. Conceptually, a broader definition of effects--that includes learning and agenda-control, as well as vote choice--characterizes contemporary research. This research also features two kinds of interactive models that are more complex than the traditional hypodermic (message-based) approach. The resonance model considers the relationship between message content and receivers' predispositions, while the strategic model highlights the interactions between competing messages. Finally, we attribute the emergence of stronger evidence in favor of campaign effects to the use of new methodologies including experimentation and content analysis, as well as the more sophisticated use of sample surveys.

The effect of lumbar sympathectomy on increased tactile sensitivity in spinal nerve ligated rats

The aim of this study was to investigate the reason for the contradictory results following surgical sympathectomy on increased tactile sensitivity in spinal nerve ligated rats. For this purpose, firstly the results of L5 spinal nerve ligation alone and both L5 and L6 (L5/6) spinal nerve ligation were compared in Sprague-Dawley rats. Secondly, the difference in tactile sensitivity between the plantar surface (the middle glabrous area on the foot pads of the hind paw) and on the toe (the proximal half of the third and fourth toe of the hind paw) after the spinal nerve injury was studied. Third, we divided the L5 spinal nerve ligated rats into two groups, (i.e. low and high threshold groups) based on the degree of tactile sensitivity and investigated the effect of surgical lumbar sympathectomy (L2-L5) on tactile sensitivity in both the plantar and toe areas. The results show that the tactile sensitivities of L5 spinal nerve ligated rats and L5/6 spinal nerve ligated rats were not different. However, tactile sensitivities of the plantar surface were less than those of toe area suggesting that the response from toe is a better indicator of neuropathic pain. Surgical sympathectomy reduced the response from only the toe area and only in the low threshold group. These results suggest that the reason for the contradictory results of surgical sympathectomy in spinal nerve ligation models is, at least in part, the difference in the degree of mechanical allodynia in each study.

Dose-response study of the analgesic effect of lanepitant in patients with painful diabetic neuropathy

Lanepitant is effective in the formalin analgesic model suggesting efficacy in painful neuropathy. This study was designed to evaluate the dose-response effect of lanepitant in patients with daily moderate to severe, bilateral, distal neuropathic pain. After a 1-to 3-week lead-in period, patients were randomly allocated to double-blind, parallel treatment with lanepitant 50 mg daily (n = 27), 100 mg daily (n = 27), 200 mg twice daily (n = 13), or placebo (n = 26) over 8 weeks. Patients reported average daytime pain and average nighttime pain intensity. Plasma concentrations and amount of adjunctive analgesic medication were obtained at all visits after baseline. Patient global evaluation and clinician global impression were obtained at weeks 3 and 8. Safety was assessed by adverse events, vital signs, laboratory analytes, and electrocardiogram. No dosage of lanepitant differed significantly from placebo. Efficacy did not increase with lanepitant dosage, and higher plasma concentrations were no more effective than lower plasma concentrations. The adverse event diarrhea was more frequent for lanepitant-treated patients. Although well tolerated, lanepitant was ineffective in relieving pain of diabetic neuropathy.

Inaccuracy of clinical phenotyping parameters for hypertensive nephrosclerosis

BACKGROUND

Multiple studies suggest that hypertension-induced end-stage renal disease (ESRD) is heritable. Identification of nephropathy susceptibility genes absolutely requires accurate phenotyping, but the clinical hypertensive nephrosclerosis (HN) phenotype is poorly characterized. We hypothesized that many patients with HN as the indicated cause of ESRD on the Health Care Financing Administration (HCFA) 2728 form, fail to satisfy stringent HN phenotyping criteria.

METHODS

Since renal biopsy documentation of HN is uncommon, clinical parameters for HN phenotype were applied: family history of hypertension, left ventricular hypertrophy, proteinuria <0.5 g/day, and hypertension preceding renal dysfunction (Schlessinger et al., 1994) or urine protein:creatinine (prot:creat) ratio <2.0 and no evidence of other renal diseases (AASK Trial Group, 1997).

RESULTS

ESRD patients (n=607, 73% African American, 25% Caucasian) were enrolled in a study to identify HN susceptibility genes. HN was the most common cause of ESRD according to HCFA 2728 forms (37% prevalence). Phenotyping of randomly selected patients with HN from the total cohort revealed that 4/100 subjects satisfied the Schlessinger criteria, and 28/91 African Americans met AASK criteria for HN. From these figures, the adjusted prevalence of HN was only 1.5-13.5%. Of patients that could not be phenotyped for HN, 14 were misdiagnosed, 14 had urine prot:creat >2.0, and insufficient data were available in the remainder. Four patients underwent renal biopsy, but histology from only one was consistent with HN. If the HN phenotype definitions are revised to exclude 'hypertension preceding renal dysfunction', or proteinuria limits, then 44/100 and 39/91 patients respectively satisfy clinical phenotyping parameters for HN.

CONCLUSIONS

(i) We provide the strongest evidence to date that HN is less frequent in an ESRD population than commonly assumed if strict clinical criteria are used; many patients clinically diagnosed with HN may have undetected, treatable renal disease from other causes; (ii) relaxing HN phenotype criteria may erroneously include patients with glomerular diseases and secondary hypertension; (iii) reliance on HCFA 2728 diagnoses will confound identification of HN susceptibility genes; (iv) to attain adequate statistical power for genotype analysis, rigorous HN phenotyping will require screening an extremely large number of patients, which can be reasonably accomplished only in a multi-centre trial design.

Phasor transform to extract glucose and ascorbic acid data in an amperometric sensor

A method for separating the signals from glucose and ascorbic acid on a single recognition surface using an ac immittance technique is presented. It is proposed that each oxidation process can be represented by a unique vector based on psi and YO, and that the concentration of each analyte can be determined by monitoring the change in the admittance magnitude in the direction of the characteristic angle for that particular species. The total Faradaic admittance (YF,total) for all electroactive species present is given by a linear combination of the independent vectors from the different species. In the system tested, the analytes are glucose and ascorbic acid, the former being estimated via the measurand, hydrogen peroxide. Thus, one of the electroactive species (hydrogen peroxide) is not a bulk solution species, but is 'generated' in the enzyme matrix. The admittance measurements from ascorbic acid and the enzyme-generated hydrogen peroxide showed the characteristic phase angles of each oxidation signal, allowing for good spatial resolution. The behaviour of each of these analytes is presented and calibration curves tested. Based on the calibration curves and the basis vectors, samples containing both glucose and ascorbic acid were measured by transforming the measured total admittance from the complex Cartesian space into 'analyte space', where the X-Y axes are given by the basis vectors ŷEGHP,GOD and ŷAA,GOD, respectively.

Novel characteristics of a misprocessed mutant HERG channel linked to hereditary long QT syndrome

Hereditary long QT syndrome (hLQTS) is a heterogeneous genetic disease characterized by prolonged QT interval in the electrocardiogram, recurrent syncope, and sudden cardiac death. Mutations in the cardiac potassium channel HERG (KCNH2) are the second most common form of hLQTS and reduce the delayed rectifier K(+) currents, thereby prolonging repolarization. We studied a novel COOH-terminal missense mutation, HERG R752W, which segregated with the disease in a family of 101 genotyped individuals. When the mutant cRNA was expressed in Xenopus oocytes it produced enhanced rather than reduced currents. Simulations using the Luo-Rudy model predicted minimal shortening rather than prolongation of the cardiac action potential. Consequently, a normal or shortened QT interval would be expected in contrast to the long QT observed clinically. This anomaly was resolved by our observation that the mutant protein was not delivered to the plasma membrane of mammalian cells but was retained intracellularly. We found that this trafficking defect was corrected at lower incubation temperatures and that functional channels were now delivered to the plasma membrane. However, trafficking could not be restored by chemical chaperones or E-4031, a specific blocker of HERG channels. Therefore, HERG R752W represents a new class of trafficking mutants in hLQTS. The occurrence of different classes of misprocessed channels suggests that a unified therapeutic approach for altering HERG trafficking will not be possible and that different treatment modalities will have to be matched to the different classes of trafficking mutants.

CD4-independent, CCR5-dependent simian immunodeficiency virus infection and chemotaxis of human cells

Most simian immunodeficiency virus (SIV), human immunodeficiency virus type 2 (HIV-2), and HIV-1 infection of host peripheral blood mononuclear cells (PBMCs) is CD4 dependent. In some cases, X4 HIV-1 chemotaxis is CD4 independent, and cross-species transmission might be facilitated by CD4-independent entry, which has been demonstrated for some SIV strains in CD4(-) non-T cells. As expected for CCR5-dependent virus, SIV required CD4 on rhesus and pigtail macaque PBMCs for infection and chemotaxis. However, SIV induced the chemotaxis of human PBMCs in a CD4-independent manner. Furthermore, in contrast to the results of studies using transfected human cell lines, SIV did not require CD4 binding to productively infect primary human PBMCs. CD4-independent lymphocyte and macrophage infection may facilitate cross-species transmission, while reacquisition of CD4 dependence may confer a selective advantage for the virus within new host species.

Use of serial analysis of gene expression to generate kidney expression libraries

Chronic renal disease initiation and progression remain incompletely understood. Genome-wide expression monitoring should clarify mechanisms that cause progressive renal disease by determining how clusters of genes coordinately change their activity. Serial analysis of gene expression (SAGE) is a technique of expression profiling, which permits simultaneous, comparative, and quantitative analysis of gene-specific, 9- to 13-bp sequence tags. Using SAGE, we have constructed a tag expression library from ROP-+/+ mouse kidney. Tag sequences were sorted by abundance, and identity was determined by sequence homology searching. Analyses of 3,868 tags yielded 1,453 unique kidney transcripts. Forty-two percent of these transcripts matched mRNA sequence entries with known function, 35% of the transcripts corresponded to expressed sequence tag (EST) entries or cloned genes, whose function has not been established, and 23% represented unidentified genes. Previously characterized transcripts were clustered into functional groups, and those encoding metabolic enzymes, plasma membrane proteins (transporters/receptors), and ribosomal proteins were most abundant (39, 14, and 12% of known transcripts, respectively). The most common, kidney-specific transcripts were kidney androgen-regulated protein (4% of all transcripts), sodium-phosphate cotransporter (0.3%), renal cytochrome P-450 (0.3%), parathyroid hormone receptor (0.1%), and kidney-specific cadherin (0.1%). Comprehensively characterizing and contrasting gene expression patterns in normal and diseased kidneys will provide an alternative strategy to identify candidate pathways, which regulate nephropathy susceptibility and progression, and novel targets for therapeutic intervention.

Detection of major genes underlying several quantitative traits associated with a common disease using different ascertainment schemes

Using the Problem 2A data sets of GAW10, we assessed the power of four ascertainment schemes to localize major genes underlying a disease trait; the schemes were based on disease or quantitative trait status of nuclear families. MAPMAKER/SIBS was used to perform sib-pair analysis for all four data sets using marker data from three chromosomes, 4, 5 and 8. Each scheme varied in power to identify major genes underlying the quantitative traits depending on the genetic architecture of the data set. Three different methods, Haseman-Elston quantitative trait locus (QTL) regression analysis, maximum likelihood variance estimation and a non-parametric method, were used to assess the strength of linkage in all four data sets. False positive mappings localizing to the same region of the genome, verifiable across all three methods did not occur. Two major genes, MG1 and MG2, were successfully assigned to chromosomes 5 and 8, respectively, by at least one of the ascertainment schemes. MG1 was localized under two schemes, selection of families with exactly two affected sibs and selection of families with two sibs who had extremely discordant values for Q1. Additional weak evidence of the location of MG1 was also obtained under the other two ascertainment schemes. MG2 could not be detected by analyzing data sets ascertained either by affected sib pairs or by sib pairs with extremely discordant values for Q1. In the data set ascertained by a third strategy, selection of families with sib pairs extremely discordant for Q2, MG2 could be mapped to chromosome 8. A random ascertainment scheme yielded a data set in which we could find weak evidence for MG1 and no evidence for MG2. Thus our ability to detect major genes underlying the QTL depended on several factors which included the ascertainment scheme, the population allele frequencies, linkage and epistasis.

Effect of acute and subchronic subcutaneous urocortin on blood pressure and food consumption in ob/ob mice

Corticotropin-releasing factor and urocortin belong to a hypothalamic peptide family thought to be important in appetite regulation. The present study compared the appetite-suppressant effect of subcutaneous urocortin in obese mice to its cardiovascular effects. Acutely, urocortin (100 nmol/kg iv) reduced blood pressure and increased heart rate in urethane anesthetized nonobese mice; effects similar to those produced by subcutaneous urocortin (10 and 100 nmol/kg sc) in nonobese and ob/ob mice. Over this same dose range (10-100 nmol/kg sc), urocortin dramatically inhibited food consumption in the ob/ob mouse. To determine if the acute hypotensive effect of urocortin (10 nmol/kg sc) in the ob/ob mouse persisted after repeated urocortin administration, animals were pretreated for 3 days with urocortin (10 nmol/kg sc) or vehicle. Following urocortin pretreatment, urocortin-induced hypotension was similar to the effect in vehicle pretreated mice. However, urocortin-induced appetite suppression was reduced following 3 days of pretreatment with urocortin (10 nmol/kg sc) to ob/ob mice. These data suggest that the hypotensive and appetite-suppressant effects of urocortin are mediated by different mechanisms and tolerance to the hypotension did not readily occur in obese animals.

Study of the analgesic effect of lanepitant in patients with osteoarthritis pain

OBJECTIVE

Lanepitant selectively blocks substance P binding to the neurokinin-1 receptor, preventing neurogenic inflammation and pain transmission. Substance P is present in synovial fluid and in excess in cerebral spinal fluid. We investigated the effect of lanepitant on pain caused by osteoarthritis to evaluate the role of neurokinin-1 blockade.

METHODS

Outpatients (n = 214) with moderate to severe lower-limb osteoarthritis pain were treated for 3 weeks in a parallel, randomized double-blind study with initial doses of 20, 60, 200, or 600 mg lanepitant, 375 mg naproxen, or placebo, followed by 10, 30, 100, or 300 mg lanepitant twice a day, 375 mg naproxen twice a day, or placebo twice a day in the multiple-dose period. Pain intensity, pain relief, patient global impression, and adjunctive analgesic use were compared across treatments. Safety was evaluated with adverse events, vital signs, and laboratory assessments.

RESULTS

There was no statistically significant difference in efficacy or safety across treatments for the initial dose assessment. After 1 week of therapy, naproxen was statistically significantly (P < .05) better than placebo and lanepitant in reducing average pain. During the second and third weeks of therapy, patients receiving naproxen continued to have statistically significantly (P < .05) less pain than those receiving placebo or lanepitant despite using significantly less adjunctive analgesic medication. There were no statistically significant differences in rates of discontinuation across treatments. Lanepitant treatment was associated with diarrhea, whereas naproxen treatment was associated with gastric discomfort. There were no clinically relevant changes in vital signs or laboratory analytes for any of the treatments.

CONCLUSION

Lanepitant was ineffective in relieving osteoarthritis pain, possibly because neurokinin-1 binding of substance P does not play a significant role in osteoarthritis pain or because lanepitant fails to adequately penetrate the blood-brain barrier to affect central pain perception.

Clinical outcome after short-term psychotherapy for adolescents with major depressive disorder

BACKGROUND

Cognitive behavioral therapy has been shown to be more efficacious than alternative psychosocial interventions for the acute treatment of adolescents with major depressive disorder. However, the long-term impact of brief psychosocial interventions on the course of adolescent depression is not well established.

METHODS

One hundred seven adolescents with major depressive disorder randomly assigned to 12 to 16 weeks of cognitive behavioral therapy, systemic behavioral family therapy, or nondirective supportive therapy were evaluated for 2 years after the psychotherapy trial to document the subsequent course and predictors of major depressive disorder.

RESULTS

There were no long-term differential effects of the 3 psychotherapies. Most participants (80%) recovered (median time, 8.2 months from baseline), and 30% had a recurrence (median time, 4.2 months from recovery). Twenty-one percent were depressed during at least 80% of the follow-up period. Severity of depression (at baseline) and presence of self-reported parent-child conflict (at baseline and during the follow-up period) predicted lack of recovery, chronicity, and recurrence. Despite the similarity to clinically referred patients at baseline, patients recruited via advertisement were less likely to experience a recurrence.

CONCLUSIONS

There were no significant differences in long-term outcome among cognitive behavioral therapy, systematic behavioral family therapy, and nondirective supportive therapy. While most participants in this study eventually recovered, those with severe depression and self-perceived parent-child conflict are at greater risk for chronic depression and recurrences.

Development of topography within song control circuitry of zebra finches during the sensitive period for song learning

Refinement of topographic maps during sensitive periods of development is a characteristic feature of diverse sensory and motor circuits in the nervous system. Within the neural system that controls vocal learning and behavior in zebra finches, axonal connections of the cortical nucleus lMAN demonstrate striking functional and morphological changes during vocal development in juvenile males. These circuits are uniquely important for song production during the sensitive period for vocal learning, and the overall size of these brain regions and their patterns of axonal connectivity undergo dramatic growth and regression during this time. Axonal connections to and from lMAN are topographically organized in adult males that have already learned song. We wondered whether the large-scale changes seen in lMAN circuitry during the time that vocal behavior is being learned and refined could be accompanied by the emergence of topographic mapping. However, results presented herein demonstrate that most of these song-control circuits show the same broad patterns of axonal connectivity between subregions of individual nuclei at the onset of song learning as seen in adult birds. Thus, coarse topographic organization is not dependent on the types of experience that are crucial for vocal learning. Furthermore, this maintenance of topographic organization throughout the period of song learning is clearly not achieved by maintenance of static axonal arbors. In fact, because the volumes of song-control nuclei are growing (or regressing), topography must be maintained by active remodeling of axonal arbors to adapt to the changes in overall size of postsynaptic targets. A salient exception to this pattern of conserved topography is the projection from lMAN to the motor cortical region RA: this pathway is diffusely organized at the onset of song learning but undergoes substantial refinement during early stages of song learning, suggesting that remodeling of axonal connections within this projection during the period of vocal learning may signify the production of increasingly refined vocal utterances.

Genetic susceptibility to end-stage renal disease

New methods have been developed to uncover the genotypes that result in complex diseases. End-stage renal disease is a complex disease, without a simple correspondence between genotype and phenotype. Both population-based and family-based epidemiological studies and analysis of model organisms suggest that the pathogenesis of end-stage renal disease may have a genetic component. A number of studies have analyzed candidate nephropathy genes with little success, but recently several well-designed studies of multiplex families with diabetic nephropathy have identified candidate nephropathy susceptibility loci. To date, kidney disease-oriented research has focused on effector mechanisms responsible for the initiation and progression of chronic renal disease. However, because end-stage renal disease is a complex disease, interruption of a single effector pathway is unlikely to result in significant therapeutic benefit. Further understanding of the pathogenesis of kidney disease and the development of new kidney disease therapies will require continued application of genetic and genomic tools to kidney disease research.

T cell-tropic HIV gp120 mediates CD4 and CD8 cell chemotaxis through CXCR4 independent of CD4: implications for HIV pathogenesis

HIV entry is determined by one or more chemokine receptors. T cell-tropic viruses bind CXCR4, whereas macrophage-tropic viruses use CCR5 and other CCRs. Infection with CXCR4 and CCR5-tropic HIV requires initial binding to CD4, and chemotaxis induced by the CCR5-tropic envelope has been reported to be strictly dependent on CD4 binding. We demonstrate that, in contrast to CD4-dependent gp120 signaling via CCR5, envelope signaling through CXCR4 is CD4 independent, inducing chemotaxis of both CD4 and CD8 T cells. Signaling by virus or soluble envelope through CXCR4 may affect pathogenesis by attracting and activating target and effector cells.