A Narrative Review of Multiinstitutional Data Registries of Pediatric Congenital Heart Disease in Pediatric Cardiac Anesthesia and Critical Care Medicine.

Congenital heart disease (CHD) is one of the most common birth anomalies. While the care of children with CHD has improved over recent decades, children with CHD who undergo general anesthesia remain at increased risk for morbidity and mortality. Electronic health record systems have enabled institutions to combine data on the management and outcomes of children with CHD in multicenter registries. The application of descriptive analytics methods to these data can improve clinicians' understanding and care of children with CHD. This narrative review covers efforts to leverage multicenter data registries relevant to pediatric cardiac anesthesia and critical care to improve the care of children with CHD.

Impact of co-pay assistance on patient, clinical, and economic outcomes.

OBJECTIVES: Patient assistance programs (eg, co-pay assistance) may reduce patients' out-of-pocket costs for prescription medicines, providing financial assistance to access medicines for reduced or no cost. A literature review to identify peer-reviewed articles on studies evaluating the impact of co-pay assistance on clinical, patient, and economic outcomes was conducted. STUDY DESIGN: A literature review was conducted by searching Embase and MEDLINE. METHODS: The population of interest was patients who had received co-pay assistance; the intervention was co-pay assistance; comparator was no co-pay assistance; and outcomes were treatment adherence, compliance, discontinuation, interruption, barriers to adherence, and specific therapeutic outcomes. Articles from the United States published between January 2015 and June 2021 were included. RESULTS: A total of 1249 initial articles were identified, of which 19 published articles representing 12 studies were included. Most studies were retrospective claims analyses (n = 10); there was also 1 randomized controlled trial and 1 prospective and observational study. One article assessed the association between co-pay assistance and patient-reported outcomes, 7 explored the relationship between co-pay assistance and clinical outcomes, and 6 assessed the impact of policy/program changes on co-pay assistance. Co-pay assistance was associated with improved treatment persistence/adherence across various diseases, with limited indirect evidence of this translating into clinical outcomes improvements. Lack of long-term outcomes and uncertainty around program sustainment from co-pay assistance programs are limitations. CONCLUSIONS: Limited evidence suggests a potential link between co-pay assistance and clinical outcomes; future research addressing study design challenges in measuring the effects of co-pay assistance is needed.

Prior surgery determines islet yield and insulin requirement in patients with chronic pancreatitis.

BACKGROUND: Total pancreatectomy with islet autotransplantation (TP-IAT) is safe and effective in the management of intractable pain associated with chronic pancreatitis (CP). Prevention of pancreatogenic diabetes after TP-IAT is related to islet yield from the diseased pancreas. The purpose of this study is to compare islet yield and insulin requirement in the 76 patients who underwent different surgical procedures before TP-IAT at the Medical University of South Carolina between 2009 and 2011. METHODS: Patients were grouped into four categories based on the operation they had before TP-IAT: transduodenal sphincteroplasty/no prior surgery (n=50), Whipple or Beger procedure (n=14), distal pancreatectomy (n=8), or lateral pancreaticojejunostomy (n=4). Islets were harvested from pancreases of those patients at our current good manufacturing practice facility. Total unpurified islets were transplanted into patients via portal vein infusion. Pancreatic fibrosis, islet yield, cell viability, and insulin requirement were measured. RESULTS: The pancreases of transduodenal sphincteroplasty/no prior surgery and Whipple or Beger procedure patients were less fibrotic and had higher islet yield compared with those who had distal pancreatectomy or lateral pancreaticojejunostomy. Higher islet yield also correlated with a greater diabetes-free rate and a lesser insulin requirement at the following intervals: preoperative, postoperative, and 6 months after TP-IAT. CONCLUSIONS: Prior surgery is strongly correlated with the extent of pancreatic fibrosis, islet yield, and insulin requirements in CP patients undergoing TP-IAT. The history of prior pancreatic resection and drainage procedures may be used to predict postoperative islet function and help to determine the optimal timing for TP-IAT in CP patients.

Effect of shatapushpa taila matra basti and pathadi kwatha on poly cystic ovarian disease.

Poly Cystic Ovarian Disease (PCOD) is a complex disorder affecting 5-15% women in their reproductive age and related to ovarian dysfunction, characterized by menstrual irregularities, hyperandrogonism, obesity, and infertility. In Ayurveda, these symptoms are found under various conditions, caused by vitiated Vata and Kapha. Pathadi Kwatha and Shatapushpa Taila Matra Basti were studied in the current attempt to evaluate their comparative efficacy in cases of PCOD. Total 34 patients of PCOD were registered among which, 32 had completed the treatment of 2 months. They were randomly divided in to three groups. In group A Pathadi Kwatha (10 g, bid) and Shatapushpa Taila Matra Basti (60 ml for 7 days after cessation of menses for 2 consecutive cycles) were administered. In group B only Basti, whereas in group C capsules of roosted wheat flour were administered. Better results were obtained in group A especially in menstrual irregularities, achieving follicular growth and in weight reduction.

Extraction, purification and concentration of partially saturated canthaxanthin from Aspergillus carbonarius.

A mutant Aspergillus carbonarius produces partially saturated canthaxanthin (PSC; C(40)H(62)O(2)) during submerged fermentation. The pigment was extracted from dried biomass using various organic solvents and purified using nanofiltration (NF) and nonporous membranes. Particle size had a great influence; PSC extractability from fines fraction of biomass (75-105 microm) was 1.5-fold higher compared to the coarse fraction (850-920 microm) in ethanol. Among the four solvents, hexane exhibited the highest PSC extractability of 5.83 mg/g and purity of 32 mg/g. On a relative scale, the extraction performance of hexane, acetone, methanol and ethanol were in the order 100, 16.1, 7.5 and 5.4. An assessment based on enrichment factor and permeate flux revealed notable performance with NF-250 membrane in ethanol extract followed by NF-200 and NF-GKSS membranes in methanol extract. These results suggested the suitability of hexane for extraction followed by alcohol phase purification and concentration employing NF. Accordingly, a PSC purity of 206 mg/g was achieved.

Effect of the heating temperature on the corrosion resistance of alkali-treated titanium.

The paper presents the results of examinations of the corrosion resistance of titanium after its being subjected to the surface modification by the alkali- and heat-treatments. The material examined was commercially pure titanium (grade 2). The samples were soaked in an aqueous 10M NaOH solution at 60 degrees C for 24 h and subsequently heated at 500, 600, or 700 degrees C for 1 h. The chemical composition of the surface layers was determined by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy. The phases present in the layers were identified by XRD. The corrosion resistance was evaluated by electrochemical methods (Stern's method, potentiodynamic method, and impedance spectroscopy) at a temperature of 37 degrees C after short- and long-time exposures. The 13 h exposure was aimed to allow the corrosion potential to stabilize. The aim of the long-term exposures was to examine how the corrosion resistance of the modified samples changes during the exposure. Under the conditions prevailing during the experiments, the highest corrosion resistance was achieved with the samples heated at a temperature of 700 degrees C.

The effect of sodium-ion implantation on the properties of titanium.

This paper deals with the surface modification of titanium by sodium-ion implantation and with the effect of this modification on structure, corrosion resistance, bioactivity and cytocompatibility. The Na ions were implanted with doses of 1 x 10(17) and 4 x 10(17) ions/cm(2) at an energy of 25 keV. The chemical composition of the surface layers formed during the implantation was examined by secondary-ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS), and their microstructure--by transmission electron microscopy (TEM). The corrosion resistance was determined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C, after exposure in SBF for various times. The surfaces of the samples were examined by optical microscopy, by scanning electron microscopy (SEM-EDS), and by atomic force microscopy (AFM). Biocompatibility of the modified surface was evaluated in vitro in a culture of the MG-63 cell line and human osteoblast cells. The TEM results indicate that the surface layers formed during the implantation of Na-ions are amorphous. The results of the electrochemical examinations obtained for the Na-implanted titanium samples indicate that the implantation increases corrosion resistance. Sodium-ion implantation improves bioactivity and does not reduce biocompatibility.

Efficacy of cyclo-oxygenase-2 inhibition by etoricoxib and naproxen on the axial manifestations of ankylosing spondylitis in the presence of peripheral arthritis.

OBJECTIVE: The combined efficacy of selective and non-selective cyclo-oxygenase-2 (COX-2) inhibition on the axial manifestations of ankylosing spondylitis (AS) in the presence or absence of chronic peripheral arthritis was evaluated. METHODS: In a post hoc subgroup analysis of a 6 week, randomised, double blind, placebo controlled trial, 387 patients with active axial AS were randomised to receive etoricoxib 90 mg or 120 mg once a day, naproxen 500 mg twice daily, or placebo. Randomisation was stratified by the presence or absence of chronic peripheral arthritis. The primary outcome measure was the time weighted average change from baseline of spine pain intensity. Efficacy data from the three groups receiving active treatment (the NSAID/COX-2 inhibitor group) were combined to improve precision. An analysis of covariance model was used to evaluate the effect of peripheral disease on treatment response. RESULTS: 93 patients were allocated to receive placebo and 294 to active treatment (naproxen or etoricoxib). The combined NSAID/COX-2 inhibitor group had a significant treatment response compared with the placebo group for all efficacy measures, both in patients with and without peripheral arthritis. A significantly greater difference in mean patient assessment of spine pain was found between active and placebo treatments in patients without compared with those with peripheral arthritis (p = 0.005; -32.5 mm v -17.0 mm, respectively). Similar differences, although not statistically significant, were seen for other end points. CONCLUSION: NSAIDs and COX-2 inhibitors have a clinically relevant symptomatic effect on axial AS irrespective of the presence of peripheral arthritis. In this exploratory analysis spinal improvement appeared to be greater in patients without peripheral disease.

Corrosion resistance and bioactivity of titanium after surface treatment by three different methods: ion implantation, alkaline treatment and anodic oxidation.

The paper compares the effects of various surface modifications, ion implantation, alkaline treatment and anodic oxidation, upon the corrosion resistance and bioactivity of titanium. The chemical composition of the surface layers thus produced was determined by XPS, SIMS and EDS coupled with SEM. The structure of the layers was examined by TEM, and their phase composition by XRD. The corrosion resistance was determined by electrochemical methods after the samples were exposed to the test conditions for 13 h. The bioactivity of titanium was evaluated in a simulated body fluid at a temperature of 37 degrees C after various exposure time.

Effect of dual ion implantation of calcium and phosphorus on the properties of titanium.

This study is concerned with the effect of dual implantation of calcium and phosphorus upon the structure, corrosion resistance and biocompatibility of titanium. The ions were implanted in sequence, first Ca and then P, both at a dose of 10(17) ions/cm2 at a beam energy of 25 keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the implanted layer was examined by XPS and SIMS. The corrosion resistance was determined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. The biocompatibility tests were performed in vitro in a culture of human-derived bone cells (HDBC) in contact with the tested materials. The viability of the cells was determined by an XTT assay and their activity by the measurements of the alkaline phosphatase activity in contact with implanted and non-implanted titanium samples. The in vitro examinations confirmed that, under the conditions prevailing during the experiments, the biocompatibility of Ca + P ion-implanted titanium was satisfactory. TEM results show that the surface layer formed by the Ca + P implantation is amorphous. The corrosion resistance of titanium, examined by the electrochemical methods, appeared to be increased after the Ca + P ion implantation.

Effect of calcium and phosphorus ion implantation on the corrosion resistance and biocompatibility of titanium.

This paper is concerned with the corrosion resistance and biocompatibility of titanium after surface modification by the ion implantation of calcium or phosphorus or calcium + phosphorus. Calcium and phosphorus ions were implanted in a dose of 10(17) ions/cm(2). The ion beam energy was 25 keV. The microstructure of the implanted layers was examined by TEM. The chemical composition of the surface layers was determined by XPS and SIMS. The corrosion resistance was examined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. The biocompatibility was evaluated in vitro. As shown by TEM results, the surface layers formed during calcium, phosphorus and calcium + phosphorus implantation were amorphous. The results of the electrochemical examinations (Stern's method) indicate that the calcium, phosphorus and calcium + phosphorus implantation into the surface of titanium increases its corrosion resistance in stationary conditions after short- and long-term exposures in SBF. Potentiodynamic tests show that the calcium-implanted samples undergo pitting corrosion during anodic polarisation. The breakdown potentials measured are high (2.5 to 3 V). The good biocompatibility of all the investigated materials was confirmed under the specific conditions of the applied examination, although, in the case of calcium implanted titanium it was not as good as that of non-implanted titanium.

Use of gastroprotective agents and discontinuations due to dyspepsia with the selective cyclooxygenase-2 inhibitor etoricoxib compared with non-selective NSAIDs.

BACKGROUND: Most nonsteroidal anti-inflammatory drugs (NSAIDs) are non-selective cyclooxygenase-1 (COX-1) and COX-2 inhibitors and are associated with upper gastrointestinal (GI) dyspeptic symptoms often resulting in GI co-medication usage or treatment discontinuation. OBJECTIVE: To compare the rates of new use of gastroprotective agents and discontinuations due to dyspepsia with the COX-2 selective inhibitor etoricoxib compared with non-selective NSAIDs. RESEARCH DESIGN AND METHODS: This pre-specified combined analysis used data from nine randomized, double-blind, controlled, clinical trials with etoricoxib in patients with osteoarthritis, rheumatoid arthritis, chronic low back pain, or ankylosing spondylitis. The cumulative incidences of (1) new use (new prescription or increased dose) of gastroprotective agents (GPA) and (2) discontinuation due to dyspeptic symptoms were compared among patients treated with etoricoxib (60 mg, 90 mg, or 120 mg daily) vs. non-selective NSAIDs (diclofenac 50 mg. t.i.d. or naproxen 500 mg. b.i.d.). RESULTS: The overall rates/100 patient-years for new use of GPAs were 9.1 and 13.0 for etoricoxib and NSAIDs, respectively (RR = 0.75; 95% confidence interval [CI] 0.64, 0.89; p < 0.001). A benefit with etoricoxib was seen in the first 6 months when most new GPA usage occurred; after 6 months new use of GPAs was similar between etoricoxib and NSAIDs. The rates/100 patient-years of treatment discontinuation due to dyspeptic symptoms with etoricoxib and NSAIDs were 1.5 and 2.7, respectively (RR = 0.60; 95% CI 0.41, 0.87; p = 0.007). Analyses of placebo-controlled treatment periods showed significantly more new GPA use and more discontinuations due to dyspeptic symptoms with NSAIDs vs. placebo, but not with etoricoxib vs. placebo. CONCLUSION: In this combined analysis of clinical trials of patients with OA, RA, chronic low back pain, or AS, new use of gastroprotective agents was significantly lower with etoricoxib than with the comparator non-selective NSAIDs during the initial 6 months of treatment and similar thereafter. There were significantly fewer discontinuations for dyspeptic symptoms with etoricoxib than with NSAIDs over the entire follow-up period.

Effect of phosphorus-ion implantation on the corrosion resistance and biocompatibility of titanium.

This work presents data on the structure and corrosion resistance of titanium after phosphorus-ion implantation with a dose of 10(17)P/cm2. The ion energy was 25keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The corrosion resistance was examined by electrochemical methods in a simulated body fluid at a temperature of 37 C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both phosphorus-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by transmission electron microscope results, the surface layer formed during phosphorus-ion implantation was amorphous. The results of electrochemical examinations indicate that phosphorus-ion implantation increases the corrosion resistance after short-term as well as long-term exposures.

Rofecoxib shows consistent efficacy in osteoarthritis clinical trials, regardless of specific patient demographic and disease factors.

OBJECTIVE: To evaluate the efficacy of rofecoxib (Vioxx) in subpopulations of patients with osteoarthritis (OA) identified by demographic or baseline disease characteristics, or varied OA involvement. METHODS: Data were combined from three 6-week double blind trials in patients with OA of the knee or hip. All trials contained placebo, 12.5 mg rofecoxib, and 25 mg rofecoxib arms (the only trials to date containing all 3 treatments). Analyses were performed on subgroups categorized according to the following baseline demographics and disease characteristics [age, sex, height, weight, body mass index, American Rheumatism Association (ARA) functional class, joint tenderness, joint stiffness, Western Ontario-McMaster University OA Index (WOMAC) functional subscale, unilateral/bilateral joint involvement, number of joint groups involved]. Three primary endpoints--Pain Walking on Flat Surface (WOMAC), Patient Global Assessment of Response to Therapy, and Investigator Global Assessment of Disease Status--were analyzed. The global assessments, which provided data on overall aspects of OA, regardless of affected joint, were used to assess effects among patients with one, 2, 3, or 4 joint groups affected (from among the following: interphalangeal/first carpal-metacarpal joint, spine, hip, or knee). RESULTS: Data from 1501 patients were included. No consistent treatment-by-subgroup interaction was observed with all 3 primary endpoints for patients taking placebo or 12.5 or 25 mg rofecoxib. Rofecoxib showed generally consistent efficacy across subgroups of patients identified by sex, race, age, OA location(s), prior OA therapy, baseline study joint tenderness or swelling (patients with knee OA only), and ARA functional class level. CONCLUSION: In this combined analysis, no specific factor predicted a differential treatment effect to rofecoxib.

Role of cortical feedback in the receptive field structure and nonlinear response properties of somatosensory thalamic neurons.

Previous studies have suggested that the descending pathway from the primary somatosensory (SI) cortex to the ventral posterior nucleus of the thalamus has only a mild facilitative influence over thalamic neurons. Given the large numbers of corticothalamic terminations within the rat somatosensory thalamus and their complex topography, we sought to examine the role of corticothalamic feedback in the genesis of spatiotemporal receptive fields and the integration of complex tactile stimuli in the thalamus. By combining focal cortical inactivation (produced by microinjection of the GABA(A) agonist muscimol), with chronic multielectrode recordings, we observed that feedback from the rat SI cortex has multiple influences on its primary thalamic relay, the ventral posterior medial (VPM) nucleus. Our data demonstrate that, when single-whisker stimuli were used, the elimination of cortical feedback caused significant changes in the spatiotemporal structure of the receptive fields of VPM neurons. Cortical feedback also accounted for the nonlinear summation of VPM neural responses to simultaneously stimulated whiskers, in effect "linearizing" the responses. These results argue that the integration and transmission of tactile information through VPM are strongly influenced by the state of SI cortex.

Bilateral integration of whisker information in the primary somatosensory cortex of rats.

The isomorphic representation of the contralateral whisker pad in the rodent cerebral cortex has served as a canonical example in primary somatosensory areas that the contralateral body surface is spatially represented as a topographic map. By characterizing responses evoked by multiwhisker stimuli, we provide direct evidence that the whisker region of the rat primary somatosensory cortex (SI) integrates information from both contralateral and ipsilateral whisker pads. The proportions of SI neurons responsive to ipsilateral whisker stimuli, as well as their response probabilities, increased with the number of ipsilateral whiskers stimulated. Under bilateral whisker stimulation, the responses of 95% of neurons recorded were affected by stimulation of ipsilateral whiskers. Contralateral tactile responses of SI neurons were profoundly influenced by preceding ipsilateral stimuli and vice versa. This effect depended on both the spatial location and the relative timing of bilateral whisker stimuli, leading to both spatial and temporal asymmetries of interaction. Bilateral whisker stimulation resulted in only modest changes in evoked response latency. Previous ipsilateral stimulation was also shown to affect tactile responses evoked by later ipsilateral stimuli. Inactivation of the opposite SI abolished ipsilaterally evoked responses as well as their influence on subsequently evoked contralateral responses in the intact SI. Based on these results, we conclude that the rat SI integrates information from both whisker pads and propose that such interactions may underlie the ability of rats to discriminate bilateral tactile stimuli.

Effect of calcium-ion implantation on the corrosion resistance and biocompatibility of titanium.

This work presents data on the structure and corrosion resistance of titanium after calcium-ion implantation with a dose of 10(17) Ca+/cm2. The ion energy was 25 keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by XPS and SIMS. The corrosion resistance was examined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells (HDBC) in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both calcium-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by TEM results, the surface layer formed during calcium-ion implantation was amorphous. The results of electrochemical examinations indicate that calcium-ion implantation increases the corrosion resistance, but only under stationary conditions; during anodic polarization the calcium-ion-implanted samples undergo pitting corrosion. The breakdown potential is high (2.7-3 V).

Effects of oral administration of ibutamoren mesylate, a nonpeptide growth hormone secretagogue, on the growth hormone-insulin-like growth factor I axis in growth hormone-deficient children.

Ibutamoren mesylate (MK-0677), an orally active nonpeptide growth hormone (GH) secretagogue, stimulates GH release through a pituitary and hypothalamic receptor that is different from the GH-releasing hormone receptor. We evaluated the safety and tolerability and the GH-insulin-like growth factor (IGF) responses to two dosages of oral ibutamoren mesylate given to children with GH deficiency for 7 to 8 days. The patients, 18 prepubertal children (15 male, 3 female) with idiopathic GH deficiency, had a chronologic age of 10.6 +/- 0.8 years (mean +/- SD), bone age of 7.4 +/- 0.7 years, growth velocity < 10th percentile for age, height < 10th percentile for age, and a maximum GH response of < or = 10 microg/L to two different GH stimulation tests. The children were assigned as follows to one of three treatment groups with ibutamoren mesylate: 0.2 mg/kg per day for 7 days (days 1-7 or 8-14) and matching placebo for the alternate 7 days (groups I and II, respectively) or 0.8 mg/kg per day for 7 days (days 8-14, group III). On day 15 all patients received an 0.8-mg/kg dose of ibutamoren mesylate. Patients in groups I and II were studied first to assess safety at the low dose before advancement to the high dose. Hormonal profiles were evaluated on day -1 (baseline) and day 15, and the results were expressed as the change from baseline within each group. After administration of ibutamoren mesylate 0.8 mg/kg for 8 days (group III), the median increases (on day 15) from baseline were as follows: 3.8 microg/L (range, 0 to 34.3) for serum GH peak concentration (P = .001), 4.3 microg x h/L (range, 1.3 to 35.6) for the GH area under the concentration-time curve from time zero to 8 hours (AUC(0-8)) (P < .001), 12 microg/L (range, -4 to 116) for serum IGF-I (P = .01), and 0.4 microg/L (range, -0.9 to 1.5) for serum IGF-binding protein 3 (IGFBP-3) (P = .01). There was no change in serum prolactin, glucose, triiodothyronine, thyroxine, thyrotropin, peak serum cortisol, and insulin concentrations or 24-hour urinary free cortisol after administration of 0.8 mg/kg per day of ibutamoren mesylate for 8 days. We conclude that short-term administration of ibutamoren mesylate can increase GH, IGF-I, and IGFBP-3 levels in some children with GH deficiency. Thus this compound is applicable for testing its effect on growth velocity.

Behavioral properties of the trigeminal somatosensory system in rats performing whisker-dependent tactile discriminations.

To address several fundamental questions regarding how multiwhisker tactile stimuli are integrated and processed by the trigeminal somatosensory system, a novel behavioral task was developed that required rats to discriminate the width of either a wide or narrow aperture using only their large mystacial vibrissae. Rats quickly acquired this task and could accurately discriminate between apertures of very similar width. Accurate discriminations required a large number of intact facial whiskers. Systematic removal of individual whiskers caused a decrease in performance that was directly proportional to the number of whiskers removed, indicating that tactile information from multiple whiskers is integrated as rats gauge aperture width. In different groups of rats, different sets of whiskers were removed in patterns that preferentially left whisker rows or whisker arcs intact. These different whisker removals caused similar decreases in performance, indicating that individual whiskers within the vibrissal array are functionally equivalent during performance of this task. Lesions of the barrel cortex abolished the ability of rats to discriminate, demonstrating that this region is critically involved in this tactile behavior. Interestingly, sectioning the facial nerve, which abolished whisker movements, did not affect the ability to perform accurate discriminations, indicating that active whisker movements are not necessary for accurate performance of the task. Collectively, these results indicate that the trigeminal somatosensory system forms internal representations of external stimuli (in this case, aperture width) by integrating tactile input from many functionally equivalent facial whiskers and that the vibrissal array can function as a fine-grained distance detector without active whisker movements.

Effect of alendronate and MK-677 (a growth hormone secretagogue), individually and in combination, on markers of bone turnover and bone mineral density in postmenopausal osteoporotic women.

GH increases bone turnover and stimulates osteoblast activity. We hypothesized that administration of MK-677, an orally active GH secretagogue, together with alendronate, a potent inhibitor of bone resorption, would maintain a higher bone formation rate relative to that seen with alendronate alone, thereby generating greater enhancement of bone mineral density (BMD) in women with postmenopausal osteoporosis. We determined the individual and combined effects of MK-677 and alendronate administration on insulin-like growth factor I levels and biochemical markers of bone formation (osteocalcin and bone-specific alkaline phosphatase) and resorption [urinary N-telopeptide cross-links (NTx)] for 12 months and BMD for 18 months. In a multicenter, randomized, double blind, placebo-controlled, 18-month study, 292 women (64-85 yr old) with low femoral neck BMD were randomly assigned in a 3:3:1:1 ratio to 1 of 4 daily treatment groups for 12 months: MK-677 (25 mg) plus alendronate (10 mg); alendronate (10 mg); MK-677 (25 mg); or a double dummy placebo. Patients who received MK-677 alone or placebo through month 12 received MK-677 (25 mg) plus alendronate (10 mg) from months 12-18. All other patients remained on their assigned therapy. All patients received 500 mg/day calcium. The primary results, except for BMD, are provided for month 12. MK-677, with or without alendronate, increased insulin-like growth factor I levels from baseline (39% and 45%; P < 0.05 vs. placebo). MK-677 increased osteocalcin and urinary NTx by 22% and 41%, on the average, respectively (P < 0.05 vs. placebo). MK-677 and alendronate mitigated the reduction in bone formation compared with alendronate alone based on mean relative changes in serum osteocalcin (-40% vs. -54%; P < 0.05, combination vs. alendronate) and reduced the effect of alendronate on resorption (NTx) as well (-52% vs. -61%; P < 0.05, combination vs. alendronate). MK-677 plus alendronate increased BMD at the femoral neck (4.2% vs. 2.5% for alendronate; P < 0.05). However, similar enhancement was not seen with MK-677 plus alendronate in BMD of the lumbar spine, total hip, or total body compared with alendronate alone. GH-mediated side effects were noted in the groups receiving MK-677, although adverse events resulting in discontinuation from the study were relatively infrequent. In conclusion, the anabolic effect of GH, as produced through the GH secretagogue MK-677, attenuated the indirect suppressive effect of alendronate on bone formation, but did not translate into significant increases in BMD at sites other than the femoral neck. Although the femoral neck is an important site for fracture prevention, the lack of enhancement in bone mass at other sites compared with that seen with alendronate alone is a concern when weighed against the potential side effects of enhanced GH secretion.