The psychiatric disease risk factors DISC1 and TNIK interact to regulate synapse composition and function.

Disrupted in schizophrenia 1 (DISC1), a genetic risk factor for multiple serious psychiatric diseases including schizophrenia, bipolar disorder and autism, is a key regulator of multiple neuronal functions linked to both normal development and disease processes. As these diseases are thought to share a common deficit in synaptic function and architecture, we have analyzed the role of DISC1 using an approach that focuses on understanding the protein-protein interactions of DISC1 specifically at synapses. We identify the Traf2 and Nck-interacting kinase (TNIK), an emerging risk factor itself for disease, as a key synaptic partner for DISC1, and provide evidence that the DISC1-TNIK interaction regulates synaptic composition and activity by stabilizing the levels of key postsynaptic density proteins. Understanding the novel DISC1-TNIK interaction is likely to provide insights into the etiology and underlying synaptic deficits found in major psychiatric diseases.

Size-dependent magnetic properties of γ-Fe2O3 nanocrystallites.

A route for synthesizing monodisperse magnetic nanocrystallites of maghemite, [Formula: see text]-Fe2O3, with various sizes has been revisited. A systematic investigation of three [Formula: see text]-Fe2O3 nanocrystalline samples by different techniques has been performed to characterize their size-dependent magnetic properties. Zero-field-cooled and field-cooled magnetization measurements reveal that the superparamagnetic blocking temperatures are around 230 K, 170 K, and 50 K for the 15.0 nm, 11.8 nm, and 6.1 nm nanocrystallites, respectively. Low-temperature Mössbauer spectra show that all three nanocrystallites have the maghemite structure with all the vacancies in the B-sites. Furthermore, detailed analysis shows that there are more vacancies on the B-sites for the 6.1 nm nanocrystallites compared to 0.33 for the bulk maghemite.

Magnetic properties of γ-Fe2O3 nanoparticles in a porous SiO2 shell for drug delivery.

A method is presented for synthesizing core-shell nanoparticles with a magnetic core and a porous shell suitable for drug delivery and other medical applications. The core contains multiple γ-Fe2O3 nanoparticles (∼15 nm) enclosed in a SiO2 (∼100-200 nm) matrix using either methyl (denoted TMOS-γ-Fe2O3) or ethyl (TEOS-γ-Fe2O3) template groups. Low-temperature Mössbauer spectroscopy showed that the magnetic nanoparticles have the maghemite structure, γ-Fe2O3, with all the vacancies in the octahedral sites. Saturation magnetization measurements revealed that the density of γ-Fe2O3 was greater in the TMOS-γ-Fe2O3 nanoparticles than TEOS-γ-Fe2O3 nanoparticles, presumably because of the smaller methyl group. Magnetization measurements showed that the blocking temperature is around room temperature for the TMOS-γ-Fe2O3 and around 250 K for the TEOS-γ-Fe2O3. Three dimensional topography analysis shows clearly that the magnetic nanoparticles are not only at the surface but have penetrated deep in the silica to form the core-shell structure.

The human FGF-5 oncogene encodes a novel protein related to fibroblast growth factors.

We previously described the isolation of a human oncogene which had acquired transforming potential by a DNA rearrangement accompanying transfection of NIH 3T3 cells with human tumor DNA (X. Zhan, A. Culpepper, M. Reddy, J. Loveless, and M. Goldfarb, Oncogene 1:369-376, 1987). We now term this oncogene the FGF-5 gene, since it specifies the fifth documented protein related to fibroblast growth factors (FGFs. Two regions of the FGF-5 sequence, containing 122 of its 267 amino acid residues, were 40 to 50% homologous to the sequences of acidic and basic FGFs as well as to the sequences of the FGF-related oncoproteins int-2 and hst/KS3. The FGF-5 gene bears the three exon structures typical for members of this family. FGF-5 was found to be expressed in the neonatal brain and in 3 of the 13 human tumor cell lines examined. Several experiments strongly suggested that FGF-5 is a growth factor with properties common to those of acidic and basic FGFs. The rearrangement which activated the FGF-5 gene during DNA transfection had juxtaposed a retrovirus transcriptional enhancer just upstream from the native promoter of the gene.

Biosynthesis of human fibroblast growth factor-5.

We have analyzed the biosynthesis of human fibroblast growth factor-5 (FGF-5) at the translational and posttranslational levels. FGF-5 RNA synthesized in vitro can be translated in rabbit reticulocyte lysates to yield a 29,500-Da protein, which is consistent with the molecular weight predicted from the coding sequence. The efficiency of FGF-5 translation is dramatically enhanced if an upstream open reading frame (ORF-1) in the RNA is deleted or if both AUG codons in ORF-1 are destroyed by point mutations, while partial enhancement is achieved by individual mutation of either ORF-1 AUG codon. These data suggest that FGF-5 synthesis requires the scanning of ribosomes past the two ORF-1 AUG codons. The introduction of these ORF-1 mutations into a eukaryotic FGF-5 expression vector increases its capacity to transform mouse NIH 3T3 cells up to 50-fold upon transfection. FGF-5 is secreted from transfected 3T3 cells and from human tumor cells as glycoproteins containing heterogeneous amounts of sialic acid. Glycosidase treatments suggest that the growth factor bears both N-linked and O-linked sugars.

Fibroblast growth factor 5 proto-oncogene is expressed in normal human fibroblasts and induced by serum growth factors.

Fibroblast growth factor 5 (FGF-5) is a member of the fibroblast growth factor family with transforming potential. It has been found to be expressed in several human tumor cell lines, but nothing is known about expression of this growth factor in normal cells and its biological functions. Here we show that the FGF-5 gene is expressed in exponentially growing normal human fibroblasts. In quiescent fibroblasts, expression of FGF-5 is strongly induced by serum and several growth factors such as platelet-derived growth factor (PDGF), epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha). This induction can be mediated by at least two different pathways involving protein kinase C or cAMP-dependent kinases. Since the effect is independent of de novo protein synthesis, FGF-5 represents the product of a primary response gene. In addition our data suggest that FGF-5 is mitogenic for human fibroblasts, indicating the existence of an FGF-5-mediated positive feedback in these cells which could amplify and prolong the cellular response to the initial stimulus.

DNA hypomethylation perturbs the function and survival of CNS neurons in postnatal animals.

DNA methyltransferase I (Dnmt1), the maintenance enzyme for DNA cytosine methylation, is expressed at high levels in the CNS during embryogenesis and after birth. Because embryos deficient for Dnmt1 die at gastrulation, the role of Dnmt1 in the development and function of the nervous system could not be studied by using this mutation. We therefore used the cre/loxP system to produce conditional mutants that lack Dnmt1 in neuroblasts of embryonic day 12 embryos or in postmitotic neurons of the postnatal animal. Conditional deletion of the Dnmt1 gene resulted in rapid depletion of Dnmt1 proteins, indicating that the enzyme in postmitotic neurons turns over quickly. Dnmt1 deficiency in postmitotic neurons neither affected levels of global DNA methylation nor influenced cell survival during postnatal life. In contrast, Dnmt1 deficiency in mitotic CNS precursor cells resulted in DNA hypomethylation in daughter cells. Whereas mutant embryos carrying 95% hypomethylated cells in the brain died immediately after birth because of respiratory distress, mosaic animals with 30% hypomethylated CNS cells were viable into adulthood. However, these mutant cells were eliminated quickly from the brain within 3 weeks of postnatal life. Thus, hypomethylated CNS neurons were impaired functionally and were selected against at postnatal stages.

Concurrent radiation therapy and chemotherapy followed by esophagectomy for localized esophageal carcinoma.

PURPOSE: A prospective study was performed to determine the outcome of patients with esophageal cancer who received preoperative radiation therapy and chemotherapy followed by esophagectomy, and to determine the role of preresection esophagogastroduodenoscopy (EGD) in predicting the patients in whom surgery could possibly be omitted, and the impact of surgery on survival. MATERIALS AND METHODS: Thirty-five patients with localized carcinoma of the esophagus received concurrent external-beam radiotherapy and chemotherapy followed by esophagectomy. Patients received 45 Gy in 25 fractions. Chemotherapy consisted of continuous infusion fluorouracil (5-FU; 1,000 mg/m2/d) on days 1 through 4 and 29 through 32 and cisplatin (100 mg/m2) on day 1. Patients underwent an Ivor-Lewis esophagectomy 18 to 33 days after completion of radiotherapy. RESULTS: Eighty percent of the patients had squamous cell carcinoma and 20% had adenocarcinoma. In addition, 51% had a pathologic complete response (CR). Twenty-two of the 35 underwent a preresection EGD before resection. Seventeen of the 22 (77%) had negative pathology from the preresection EGD, but seven of the 17 (41%) had residual tumor at surgery. The median survival and disease-free survival rates for all patients were 25.8 months and 32.8 months, respectively. Eighteen patients (51%) had no tumor at resection. The median survival for these patients was 36.8 months; the median disease-free survival time has not been reached. The median survival and disease-free survival rate for the patients with residual tumor in the surgical specimen were 12.9 months and 10.8 months, respectively. CONCLUSION: Preresection EGD is not reliable for determining the presence of residual disease or the patients in whom surgery could be omitted. Twenty-five percent of the patients with residual tumor in the resected surgical specimen were long-term survivors; this suggests a benefit from esophagectomy after concurrent radiotherapy and chemotherapy.

Noninvasive assessment of the direct action of oral nifedipine and nicardipine on left ventricular contractile state in patients with systemic hypertension: importance of reflex sympathetic responses.

OBJECTIVES: This study was designed to noninvasively assess the direct action of calcium channel blockers on left ventricular contractility in humans and to establish a framework for determining the importance of reflex sympathetic responses to any pharmacologic intervention. BACKGROUND: Assessment of left ventricular contractility in patients taking calcium channel blockers by using traditional indexes of systolic performance is difficult because of the after-load-reducing and reflex sympathetic effects of the drugs. METHODS: Fifteen hypertensive patients (mean blood pressure 127 +/- 15 mm Hg) were studied with Doppler echocardiography and calibrated subclavian pulse tracings while receiving placebo and 1 week after randomization to treatment with oral nifedipine (20 mg three times daily; n = 7) or nicardipine (30 mg three times daily; n = 8). Left ventricular circumferential end-systolic wall stress versus rate-corrected velocity of shortening (Vcfc) relations were generated over a range of loads using nitroprusside. Data were acquired before and during esmolol infusion, thereby allowing assessment of hemodynamic responses with the sympathetic nervous system functionally intact as well as ablated. The adequacy of sympathetic blockade was confirmed with isoproterenol challenges. In each case, left ventricular contractile state was measured relative to placebo and esmolol data as delta Vcfc at a common end-systolic wall stress. Increased and decreased contractility were defined as delta Vcfc > 0 and delta Vcfc < 0, respectively. RESULTS: Nifedipine and nicardipine equally decreased blood pressure and end-systolic wall stress and increased left ventricular percent fractional shortening and stroke volume. Neither drug alone consistently altered ventricular contractility compared with placebo. Ablation of reflex sympathetic tone with esmolol unmasked a negative inotropic effect for nifedipine (p = 0.03 vs. esmolol alone) but not nicardipine (p = 0.68 vs. esmolol alone). The difference between the contractility effects of nifedipine plus esmolol versus those of nicardipine plus esmolol approached statistical significance (p = 0.07). CONCLUSIONS: Totally noninvasive techniques showed a differential effect on left ventricular contractility between nifedipine and nicardipine when alterations in afterload and reflex sympathetic responses were eliminated as confounding variables. This diagnostic approach, based on the use of pharmacologic probes, should have wide applicability for assessing the direct inotropic effect of any agent, even in the presence of complex primary and secondary physiologic modes of action.

Conditional deletion of brain-derived neurotrophic factor in the postnatal brain leads to obesity and hyperactivity.

Brain-derived neurotrophic factor has been associated previously with the regulation of food intake. To help elucidate the role of this neurotrophin in weight regulation, we have generated conditional mutants in which brain-derived neurotrophic factor has been eliminated from the brain after birth through the use of the cre-loxP recombination system. Brain-derived neurotrophic factor conditional mutants were hyperactive after exposure to stressors and had higher levels of anxiety when evaluated in the light/dark exploration test. They also had mature onset obesity characterized by a dramatic 80-150% increase in body weight, increased linear growth, and elevated serum levels of leptin, insulin, glucose, and cholesterol. In addition, the mutants had an abnormal starvation response and elevated basal levels of POMC, an anorexigenic factor and the precursor for alpha-MSH. Our results demonstrate that brain derived neurotrophic factor has an essential maintenance function in the regulation of anxiety-related behavior and in food intake through central mediators in both the basal and fasted state.

Generation and characterization of a polyclonal antipeptide antibody to human glycodelin.

OBJECTIVE: To develop and characterize an antiglycodelin antibody using a 15-amino acid synthetic peptide as antigen, derived from the sequence of human glycodelin. DESIGN: We have developed a chicken antiglycodelin-derived peptide antibody and have characterized the antibody with the use of endometrial and ovarian cell lines. The antibody was also tested for its ability to detect glycodelin by ELISA assay, immunocytochemistry, and by Western blot. SETTING: Various cell lines, cell culture medium, and amniotic fluid were used in the experiments. PATIENT(S): Amniotic fluid was collected from pregnant patients in their first trimester of pregnancy. INTERVENTION(S): No intervention. MAIN OUTCOME MEASURE(S): Detection of glycodelin. RESULT(S): The cell lines RL95-2 (human endometrial carcinoma cells), OVCAR-3 (human ovarian adenocarcinoma cells), HeLa (human cervical epitheloid carcinoma cells), and EM42-D (human endometrial epithelial cells) reacted with the antibody, indicating the presence of glycodelin. A specific 45-kd protein representing glycodelin was detected by Western blot in the amniotic fluid. CONCLUSION(S): Antipeptide antibodies can be successfully used to detect and quantify the presence of glycodelin in cells and fluids.

Biomechanical factors associated with injury during landing in jump sports.

Many sport and movement activities contain a jumping component which necessitates landing. Several injury surveys across a variety of jump sports have identified the lower extremities and specifically the knee joint as being a primary injury site. Factors which might contribute to the frequency and severity of such injuries include stresses to which the body is subjected during performance (forces and torques), body position at landing, performance execution and landing surface. Most of the initial landing studies were primarily descriptive in nature with many of the more recent efforts being directed toward identifying the specific performance factors that could account for the observed system stresses. Continued investigations into landing are necessary to more thoroughly understand the force attenuation mechanisms and critical performance variables associated with lower extremity injuries.

Modifying hypnotic suggestibility with the Carleton Skills Training program.

The Carleton Skills Training (CST) program was used to investigate (a) whether increases in hypnotic responsiveness obtained at Carleton University could be replicated at a different laboratory, (b) the influence of demand characteristics on suggestibility gains, and (c) whether initial gains are maintained over time. After two screening sessions, a replication and experimental group received the CST program, while a control group was allowed to practice hypnotic responding. All groups were then tested twice. Whereas the replication group was told that training and testing were part of the same experiment, the experimental group was told that training and testing were unrelated. Trained subjects returned after 4 months for a final session. Results indicated that (a) the CST program does increase hypnotic responsiveness, (b) suggestibility gains found in this study were relatively modest, (c) demand characteristics may influence suggestibility gains, and (d) suggestibility gains were not maintained at follow-up.

Single-subject methodology: an alternative approach.

The purpose of this paper is to identify and discuss an alternative experimental methodology, single-subject (SS) design. The primary premise for SS analyses forms the basis for many research questions in areas such as movement/motor control, individual performance patterns/strategies, and injury mechanisms. A brief historical perspective elucidating the evolution of modern-day group statistical techniques and the relationship to the individual is presented. Rationale for the SS design within this context is also discussed. Specific statistical applications include mean comparison tests (ANOVA, Model Statistics), correlation, and multiple regression. Validation of the underlying statistical assumptions of independence and normality relative to the applications are briefly discussed. Finally, several examples are included.

The assessment of mechanical and neuromuscular response strategies during landing.

The purpose of this study was to assess relative contributions of mechanical and neuromuscular mechanisms to control of landing. Proposed mechanical and neuromuscular response strategies were evaluated relative to lower extremity impact force attenuation. Four subjects performed three conditions of 25 landings from a 60-cm height on each of two days. Additional masses were attached at each ankle for the second and removed for the third condition. Vertical ground reaction force and integrated electromyographic (IEMG) data were used to assess responses. Fourteen of 32 total single subject comparisons were significant in a mechanically predicted direction, indicating the presence of both mechanical and neuromuscular response strategies among subjects. Responses in the mechanical direction for rearfoot impact were consistent with a model predicting mechanical force changes. The presence of mechanical responses for forefoot impact not completely accounted for by the model suggested that the definition of a neuromuscular response not be limited to responses functioning in a protective manner. Multiple regression analyses relating added mass and IEMG to impact force magnitude demonstrated the complex nature of all responses. Vastus medialis IEMG was the most common independent variable included in regression models, emphasizing the importance of knee musculature in landing control.

The evaluation and prediction of impact forces during landings.

The investigation of impact force attenuation during landings may help identify performance strategies. The purpose of the study was to evaluate the effects of height (three), distance (three), and technique (three) on impact forces during landings. Three male volunteer subjects were filmed while performing three right foot landings onto a force platform for each combination of height, distance, and technique for a total of 81 trials per subject. Between- and within-subject three-way ANOVAs and three regression models (mechanical, biomechanical, refined biomechanical) were computed on the dependent variables of first (F1) and second (F2) maximum vertical force. Results of the between-subject ANOVAs indicated significant (P less than 0.05) height, distance, and technique main effects for F1 and a height x technique interaction for F2. The within-subject ANOVA results identified unique models for each of the three subjects. The biomechanical regression model exhibited the best predictions of F1 and F2 for S1 (81.0 and 72.0% explained variance, respectively), while the refined biomechanical model accounted for 83.4, 81.3, 80.9, and 88.0% of the F1 and F2 variances for S2 and S3, respectively. In conclusion, the within-subject results identified unique individual landing strategies that were masked by the group analyses suggesting that caution be exercised in using between-subject analysis techniques.

Biomechanics of the squat exercise using a modified center of mass bar.

The purpose of the study was to investigate the effects of load height on selected performance characteristics of a squat exercise. A lower center of mass bar was designed that allowed the integrity of the squat exercise to be maintained while possibly reducing the chances of injury. Five trials were performed with the center of mass of the bar was set at shoulder height (C1) and lowered 18% (C2) and 36% (C3) of the subject's height below the normal bar position using the inverted "U" bar. All trials were filmed as the subjects lifted on a force platform. A balloon catheter was inserted into the subject's recta to monitor intra-abdominal pressure (IAP). High correlations were found between IAP, joint moment, and force data. Many of the critical parameters occurred just after the lowest squat position. Significant differences (P less than 0.05) in trunk angle excursion and trunk angular velocity indicated a greater ease of hip extension for the center of mass bar conditions. No differences were observed between conditions for thigh and knee angles and joint moments indicating kinematic similarity for the lower extremity. IAP was always least for C2 and C3, while compression, shear, and back muscle forces did not differ. It was estimated that the greater IAP was responsible for relieving back muscle forces and compression by up to 15 and 21%, respectively, and increased stress with the weight at shoulder height stimulated a response for greater IAP to help alleviate the stresses on the spine.

Timing of lower extremity joint actions during treadmill running.

It has been suggested that a disruption in timing between the subtalar and knee joints may be a possible mechanism for knee injury. It has also been documented that shoe construction can alter rearfoot motion. The purpose of the study was to describe the relationship between the subtalar and knee joint actions during the support phase of treadmill running while wearing different shoes. Twelve healthy subjects ran in each of three running shoes with unique midsole durometers (C1, 70; C2, 55; C3, 45). High-speed video (200 Hz) of the rear and sagittal views of each subject/condition were taken during the last minute of a 5-min run. Retro-reflective markers were processed to determine the rearfoot angle and the sagittal view knee angle. The shoes were also subjected to a midsole material impact test. The impact test results indicated a linear trend in peak g and time to peak g across midsoles with the firmer midsole having a greater peak g and a shorter time to peak g. The results of the kinematic analysis indicated that there were no significant differences among the shoe conditions for the knee flexion parameters. However, there were significant differences in both the magnitude and the time to maximum pronation between the two firmer midsole conditions (C1 and C2) and the softer midsole condition (C3), indicating a nonlinear trend for these parameters. The softer midsole exhibited greater pronation values and a shorter time to maximum pronation.(ABSTRACT TRUNCATED AT 250 WORDS)