Testing the self-consistency of the excursion set approach to predicting the dark matter halo mass function.

The excursion set approach provides a framework for predicting how the abundance of dark matter halos depends on the initial conditions. A key ingredient of this formalism is the specification of a critical overdensity threshold (barrier) which protohalos must exceed if they are to form virialized halos at a later time. However, to make its predictions, the excursion set approach explicitly averages over all positions in the initial field, rather than the special ones around which halos form, so it is not clear that the barrier has physical motivation or meaning. In this Letter we show that once the statistical assumptions which underlie the excursion set approach are considered a drifting diffusing barrier model does provide a good self-consistent description both of halo abundance as well as of the initial overdensities of the protohalo patches.

Evidence that temporal lobe is a default area in absence epilepsy.

Correctly classifying seizures is essential for appropriate epilepsy management. Focal and generalized epilepsy rarely occur independently in the same patient. Cases of focal ictal evolution during seizures that are generalized in onset have been reported though these have included a small heterogeneous series of patients with generalized epilepsy and features on the EEG. We wish to report two patients with absence epilepsy that were noted on video-EEG monitoring to manifest a focal temporal electroclinical transformation from a typical absence seizure. Defining the electroclinical spectrum of absence seizures could add to our understanding of the selective cortical and subcortical networks that are involved in patients with "prototypic" generalized and focal seizures.

Moving the Needle Toward Fair Compensation in Pediatric Nephrology.

Remuneration issues are a substantial threat to the long-term stability of the pediatric nephrology workforce. It is uncertain whether the pediatric nephrology workforce will meet the growing needs of children with kidney disease without a substantial overhaul of the current reimbursement policies. In contrast to adult nephrology, the majority of pediatric nephrologists practice in an academic setting affiliated with a university and/or children's hospital. The pediatric nephrology service line is crucial to maintaining the financial health and wellness of a comprehensive children's hospital. However, in the current fee-for-service system, the clinical care for children with kidney disease is neither sufficiently valued, nor appropriately compensated. Current compensation models derived from the relative value unit (RVU) system contribute to the structural biases inherent in the current inequitable payment system. The perceived negative financial compensation is a significant driver of waning trainee interest in the field which is one of the least attractive specialties for students, with a significant proportion of training spots going unfilled each year and relatively stagnant growth rate as compared to the other pediatric subspecialties. This article reviews the current state of financial compensation issues plaguing the pediatric nephrology subspecialty. We further outline strategies for pediatric nephrologists, hospital administrators, and policy-makers to improve the landscape of financial reimbursement to pediatric subspecialists. A physician compensation model is proposed which aligns clinical activity with alternate metrics for current non-RVU producing activities that harmonizes hospital and personal mission statements.

Preparation and Optimization of Fast Dissolving Film of Naratr iptan Hydrochloride.

BACKGROUND: Naratriptan is second-generation triptan class of antimigraine drug which selectively bind with 5-HT(1B/1D) receptor. It is widely used to treat the migraine attack due to its better tolerability and lower recurrence rate as compared to other triptans. Despite of the applicability, Naratriptan also have several drawback like slow onset of action and fist pass metabolism which reduce its efficacy. In order to increase the efficacy of naratriptan fast dissolving film is prepared. METHOD: Fast dissolving film of Naratriptan hydrochloride was prepared by solvent casting method Based on the patent survey (US 7648712 B2, WO 2012053006 A2, US 20090047330 A1, EP 2821066 A4, WO 2008108940 A1, WO 2010151020 A3) excipients were screened to find out suitable combination of polymer and plasticizer and Hydroxypropylmethyl Cellulose (HPMC E6) and glycerol were selected as film forming polymer and plasticizer respectively. To study the effect of independent variables on dependent variables 32 full factorial design was applied using Concentration of HPMC E6 and Concentration of Glycerol as independent variables and disintegration time, folding endurance, tensile strength and cumulative % drug release at 2 min as dependent or response variables. A statistical model incorporating interactive and polynomial terms was utilized to evaluate the responses. Result & Conclusion: From the results of statistical evaluation batch F3 was selected as the optimized batch which exhibited shorter disintegration time (22sec) with satisfactory mechanical properties (tensile strength 652.17 gm/mm2). Dissolution of drug from F3 formulation was rapid with around 91% drug release in 120sec. Optimized batch was further evaluated for in vitro permeation study using Franz diffusion cell.

Status epilepticus associated with cefepime.

Cefepime is a fourth-generation cephalosporin widely used for gram-negative sepsis. The authors report two patients in whom nonconvulsive status epilepticus developed while they were on treatment with cefepime for Pseudomonas aeruginosa infection. The status epilepticus resolved completely once the drug was withdrawn. Cefepime therapy can result in status epilepticus, especially if given in higher doses than required.

Pain activation of human supraspinal opioid pathways as demonstrated by [11C]-carfentanil and positron emission tomography (PET).

The role of the supraspinal endogenous opioid system in pain processing has been investigated in this study using positron emission tomography imaging of [11C]-carfentanil, a synthetic, highly specific mu opioid receptor (mu-OR) agonist. Eight healthy volunteers were studied during a baseline imaging session and during a session in which subjects experienced pain induced by applying capsaicin topically to the dorsal aspect of the left hand. A pain-related decrease in brain mu-OR binding was observed in the contralateral thalamus consistent with competitive binding between [11C]-carfentanil and acutely released endogenous opioid peptides. This decrease varied directly with ratings of pain intensity. These results suggest that the supraspinal mu-opioid system is activated by acute pain and thus may play a substantial role in pain processing and modulation in pain syndromes.

Bone mineral density in geographically diverse adolescent populations.

OBJECTIVE: Measure bone mineral density (BMD) in healthy Newfoundland adolescents and determine whether BMD is comparable in geographically diverse adolescent populations. STUDY DESIGN: Lumbar spine BMD was measured by dual-energy radiograph absorptiometry in 26 healthy adolescents between ages 8 and 20 years. The age and gender of these subjects were used to predict BMD from equations derived from normative BMD data in six geographically diverse populations. The actual BMD value obtained for each subject was then compared with each of the six predicted BMD values for that adolescent using the Wilcoxon signed-ranks test. RESULTS: Actual lumbar spine BMD in Newfoundland adolescents was not significantly different from that predicted by age and gender if they were from California, Finland, France, North Carolina, and Switzerland. Only the prediction based on the Spanish population resulted in a 4% greater BMD than was actually measured in the Newfoundland adolescents. CONCLUSIONS: Lumbar spine BMD measurements for most healthy adolescent populations, as in adults, are comparable despite geographic diversity. Thus, generation of institution-specific normative BMD data may not be necessary for most adolescent populations.

Successful use of Tesio catheters in pediatric patients receiving chronic hemodialysis.

Semipermanent venous catheters remain the most commonly used access for chronic hemodialysis (HD) in pediatric patients. The recent availability of Tesio catheters in 7 and 10 F has expanded available HD catheter options for children and adolescents. We report our experience with Tesio catheter survival, complications, and effect on dialysis adequacy in comparison to standard dual-lumen (DL) catheters in our pediatric HD patients. Demographic data were similar between the two groups. Overall actuarial survival was significantly longer for Tesio versus DL catheters (46% versus 0% at 1 year; P = 0.003). A comparison of smaller catheters (7 F Tesio catheter, 8 or 10 F DL catheter) showed that smaller Tesio catheters had a significantly longer survival (median survival, 244 versus 13 catheter-days; P < 0.01). Tesio 10 F catheters also survived significantly longer than the larger 11.5 and 12 F DL catheters (P < 0.02). Catheter sepsis occurred less frequently with Tesio catheters (one episode/20 catheter-months) than DL catheters (one episode/5 catheter-months) despite the longer duration of Tesio catheters. Adequate dialysis (single-pool Kt/V > 1.2) was delivered with the same frequency, but for a longer duration with Tesio catheters (76% +/- 32% over 100 monthly measurements versus DL catheter, 57% +/- 45% over 54 monthly measurements). Our clinical practice was to replace cuffed catheters when adequate dialysis could not be delivered. We conclude that Tesio catheters provide superior performance compared with DL catheters in terms of catheter survival, infection rates, and duration of adequate performance.

A random walk through models of nonlinear clustering.

A few simple models of the mass function of collapsed objects are presented. The emphasis is on apparently unrelated models which end up giving the same answer for the number density and merger histories of virialized clumps. Models of the spatial distribution of the clumps and how they can be used to model the spatial distribution of the mass are briefly discussed.

Longitudinal head growth in developmentally normal preterm infants.

OBJECTIVE: To determine growth in head circumference from birth to 18 months of age in normal infants with low birth weight. METHODS: Healthy, appropriate-for-gestational-age, singleton, white infants weighing less than or equal to 2500 g at birth and with normal development at 18 months of age were included in this study. Serial measurements of head circumference (corrected for gestational age) from 450 eligible infants were compared with reference data for head circumference. RESULTS: Longitudinal measurements of head circumference for infants weighing more than 1000 g at birth were similar to reference data for term infants. Head measurements for infants weighing less than or equal to 1000 g at birth were notably smaller than the measurements in the reference data. A cubic spline curve drawn through the head circumference measurements between birth and age 18 months (corrected for gestational age) for infants weighing less than or equal to 1000 g at birth was significantly (P < .001) below the curve for infants weighing more than 1000 g at birth. At age 18 months, the mean difference in head circumference between the group weighing less than or equal to 1000 g at birth and the weights in the reference data was 1.6 cm (P < .01). (Data were analyzed with Wilcoxon's signed rank test.) CONCLUSIONS: These data show that head circumference grids are appropriate for observing head growth in infants with a birth weight more than 1000 g. However, head circumference growth for normal infants with birth weight less than or equal to 1000 g does not "catch up" with that of larger premature infants or term infants.

Object naming and semantic knowledge in temporal lobe epilepsy.

Object-naming impairment is common among temporal lobe epilepsy (TLE) patients, but other aspects of semantic memory have received limited attention in this population. This study examined object-naming ability and depth of semantic knowledge in healthy controls (n = 29) and patients with early onset TLE (n = 21). After administration of the Boston Naming Test (BNT), the authors asked participants to provide detailed definitions of 6 BNT objects. The TLE group demonstrated a significant deficit relative to controls in both object-naming ability and semantic knowledge for the target objects, even after controlling for IQ. In a multiple regression analysis that included other neuropsychological test scores as independent variables, the semantic knowledge score was the only significant predictor of patients' object-naming performance. Thus, at the group level, early onset TLE patients have a semantic knowledge deficit that contributes to dysnomia.

A multi-centre comparative study of diclofenac sodium and a dipyrone/spasmolytic combination, and a single-centre comparative study of diclofenac sodium and pethidine in renal colic patients in India.

A single-blind, randomized clinical trial was carried out to compare the analgesic effectiveness in patients with renal colic of single intramuscular doses of diclofenac sodium (75 mg) versus a dipyrone (1 g)/spasmolytics combination, and diclofenac sodium (75 mg) versus pethidine (75 mg). The first study involved three centres, the second study one centre. In total, 107 patients were treated with diclofenac sodium, 85 with dipyrone/spasmolytics, and 25 with pethidine. Assessments were made during the first hour after drug administration of the degree of pain relief, the severity of pain using a visual analogue scale, and the duration of analgesia. A global assessment of treatment efficacy was made by the participating physicians at the end of the study period. Patients treated with diclofenac sodium showed an earlier onset of analgesia and a higher incidence of total pain relief compared to those treated with dipyrone/spasmolytics or pethidine. Although the mean duration of analgesia was only slightly greater in the diclofenac sodium group than in the dipyrone/spasmolytics group, a significantly longer effect was seen when diclofenac sodium was compared with pethidine (p less than 0.01). Pain severity assessments revealed that diclofenac sodium caused a significantly greater improvement in pain after 60 minutes compared to dipyrone/spasmolytics (p less than 0.05) and after 30 minutes compared to pethidine (p less than 0.05). Global efficacy assessments by the physician rated diclofenac sodium as significantly superior to dipyrone/spasmolytics (p less than 0.01) and pethidine (p less than 0.001). Moreover, diclofenac sodium was better tolerated than either of the comparative treatments. The results indicate that intramuscular diclofenac sodium is a useful alternative to the drugs commonly used in India in the treatment of renal colic.

Aggression in children treated with clobazam for epilepsy.

Seven of 63 children (11%) treated with clobazam (CLB) for refractory epilepsy developed a severe behavior disorder. This disorder was characterized by aggressive agitation, self injurious behavior, insomnia, and incessant motor activity occurring between 10 and 55 days after initiation of drug therapy. The affected children were relatively young (mean age 6.4 years) and developmentally disabled (four were autistic and two had isolated mental retardation). The disorder occurred with a short latency after initiation of therapy and at a relatively low dosage of CLB. Serum levels of other coadministered antiepileptic drugs were unchanged by the administration of CLB. One child was taking CLB monotherapy. This behavioral deterioration required the discontinuation of CLB, after which patients returned to their previous behavior within 3 weeks. After > 3 years of follow-up all children continue to require multiple antiepileptic drugs but have not had a recurrence of this aggressive agitation. The mechanism of the behavioral change is unclear.

Vigabatrin in childhood epilepsy: comparable efficacy for generalized and partial seizures.

Thirty-one patients, aged 12.6 +/- 5.6 years, with refractory seizures for 8 +/- 4.3 years, were treated with adjunctive vigabatrin. Twenty-four percent had a > 50% reduction in seizure frequency (95% one-sided confidence interval). Generalized myoclonic, atonic, and tonic clonic and partial, with and without secondary generalization, seizures were all reduced at a mean dose of 70 +/- 38 mg/kg/day. Comparison of vigabatrin therapy duration, for partial and generalized seizure groups, utilizing Kaplan-Meier methodology showed similar survival times. Vigabatrin therapy was ineffective in the four children with tuberous sclerosis. Transient somnolence, ataxia and dizziness were the most frequent side effects. A severe aggressive agitation occurred in three patients, and necessitated discontinuation of vigabatrin in one patient. Vigabatrin was as effective in generalized as in partial seizures in this study. Clinical utility may be limited by unacceptable behavioral side effects in some patients.

Midazolam in the treatment of refractory neonatal seizures.

Midazolam, a potent short-acting benzodiazepine, is a safe and highly effective agent for the control of status epilepticus. Its efficacy in the control of neonatal seizures, however, has not been determined. Six neonates (aged 1-9 days; gestation, 30-41 weeks) developed seizures from a variety of causes. In each case, seizures persisted for > 12 h despite high-dose phenobarbital therapy with or without the addition of phenytoin. Midazolam was then administered by continuous intravenous infusion (0.1-0.4 mg/kg/h) for 1 to 3 days. Within 1 h of initiation of midazolam, seizures were controlled in all six neonates. Electroencephalographic seizures were abolished in four of six neonates; however, two neonates continued to have electrographic seizures (without clinical accompaniment) for a further 12 h. Blood pressure and pulse rate were not changed after the initiation of midazolam, and adverse reactions were not observed in any neonate. Because more than one third of all neonatal seizures are refractory to high-dose phenobarbital and phenytoin, midazolam administered by continuous intravenous infusion may be a valuable adjunctive therapy.

Size of the corpus callosum in cerebral palsy.

It has been suggested that the size of the corpus callosum may have diagnostic significance in cerebral palsy, although this relationship is incompletely defined. Ninety-one patients with cerebral palsy had been studied by magnetic resonance imaging in the 5-year period from 1990 to 1994. Fifty-seven of these 91 patients had a technically appropriate midsagittal magnetic resonance image for quantitative morphometric analysis. The ratio of the area of the corpus callosum to the area of the supratentorial brain was compared to published age- and gender-specific norms. Imaging findings were correlated with clinical history and cause of cerebral palsy. The corpus callosum was of normal size in 43 patients and more than 2 standard deviations below the mean in 14 patients. The causes for cerebral palsy included hypoxic ischemic encephalopathy (32), cerebral dysgenesis (8), and porencephalic strokes (6); the etiology could not be established in 11 patients. The size of the corpus callosum was highly correlated with the cause of cerebral palsy, such that all patients with cerebral dysgenesis had hypoplasia of the corpus callosum (one-sided z test, p < 0.0001). Conversely, the callosum was of normal size in 32 of 38 patients with hypoxic ischemic encephalopathy and porencephalic strokes. The presence of a hypoplastic corpus callosum is highly associated with cerebral dysgenesis as a cause for cerebral palsy.

Cerebral dysgenesis. An overview.

A significant portion of patients with neurodevelopmental abnormalities (mental retardation, learning disabilities, and so forth) have no definable cause for these problems. Mounting evidence suggests a substantial number of these idiopathic conditions have subtle abnormalities of brain development (cerebral dysgenesis) as the inherent pathophysiologic event. In this article the authors summarize normal and abnormal brain development, the diagnostic approach to idiopathic neurodevelopmental anomalies, and the new molecular genetic insights into the underlying causes of brain malformations.

Trends in incidence and severity of intraventricular hemorrhage.

The incidence of germinal matrix-intraventricular hemorrhages declined from 50% in 1977 to 24% in 1985. Over the last decade intraventricular hemorrhage rates ranging from 8% to 56% were reported, leaving uncertainty as to the direction of recent intraventricular hemorrhage trends. Records of all 1950 neonates weighing 2250 g or less at birth (867 weighing 1500 g or less and 1083 weighing 1501-2250 g) at a university neonatal intensive care unit between 1986 and 1995 were studied. Intraventricular hemorrhage rate declined by 53%, from 11.5% in 1986 to 5.5% in 1995 (P < .01), and was consistent across all birthweight groups: 750 g or less from 36% to 24%, 751-1000 g from 38% to 22%, 1001-1250 g from 19% to 13%, 1251-1500 g from 12% to 2% and 1551-2250 g from 3% to 0.2% (P < .05). Proportionately, severe intraventricular hemorrhage (grades 3 +/- intraparenchymal hemorrhage) declined from 70% of all intraventricular hemorrhages in 1986 to 23% in 1995 (P < .005). Overall mortality declined by 65% between 1986 and 1995 (P < .001), whereas mortality associated with intraventricular hemorrhage declined by 30% (P = .34). Despite dramatic declines in intraventricular hemorrhage rates, 21% of infants weighing less than 1000 g and 12% of those weighing less than 1500 g at birth were affected in 1995.

Frequency of neurologic disorders in the neonatal intensive care unit.

Neonatal intensive care unit survival rates have improved significantly over the past decade. This improvement primarily reflects declining mortality rates among preterm infants. Neurologic morbidity increases with prematurity and is the major predictor of long-term disability. Accordingly, concern has been expressed that the burden of neurologic dysfunction among contemporary neonatal intensive care unit survivors may be increasing. To define the trends of neurologic disorders in the contemporary neonatal intensive care unit, all 4164 admissions between 1986 and 1995 to a tertiary neonatal intensive care unit were examined. Neonatal intensive care unit admissions (413 +/- 49 per year), proportion of births at less than 37 weeks (70 +/- 3% per year), and referral patterns were stable between 1986 and 1995. Over the study period, 773 (18%) of 4164 neonatal intensive care unit infants had a total of 1062 neurologic disorders. The neonatal intensive care unit mortality rate declined from 12% in 1986 to 4.2% in 1995 (P < .01). Neurologic disorders declined, from 27% of infants born in 1986 to 12% in 1995 (P < .001): 356 had seizures (14% in 1986 to 4% in 1995; P < .001), 235 had hypoxic-ischemic encephalopathy (8% in 1986 to 4% in 1995, P < .01), and 167 had intraventricular hemorrhage (7% in 1986 to 1.4% in 1995, P < .005). Frequency of congenital or chromosomal aberration affecting the nervous system was relatively constant (4.5% per year). Despite a three-fold improvement in neonatal intensive care unit survival between 1986 and 1995, the frequency of perinatally acquired neurologic disorders declined by more than 50%.

Gelastic seizures of neocortical origin confirmed by resective surgery.

Ictal laughter is a relatively unusual phenomenon that appears to arise from within hypothalamic hamartomas. Gelastic seizures of neocortical origin are rare and when reported typically originate from temporofrontal regions in proximity to the hypothalamus, raising the possibility of a subtle lesion in the hypothalamus. A girl with gelastic seizures originating in a dysembryoblastic neuroepithelial tumor at the cranial vertex had resolution of her seizures following surgical resection. Electrical propagation of seizures via the cingulate gyrus appears to be an alternative mechanism underlying gelastic seizures.