Calmodulin plays a pivotal role in cellular regulation

The role of calcium ions (Ca2+) in cell function is beginning to be unraveled at the molecular level as a result of recent research on calcium-binding proteins and particularly on calmodulin. These proteins interact reversibly with Ca2+ to form a protein . Ca2+ complex, whose activity is regulated by the cellular flux of Ca2+. Many of the effects of Ca2+ appear to be exerted through calmodulin-regulated enzymes.

Increased NMDA current and spine density in mice lacking the NMDA receptor subunit NR3A

The NMDA (N-methyl-D-aspartate) subclass of glutamate receptor is essential for the synaptic plasticity thought to underlie learning and memory and for synaptic refinement during development. It is currently believed that the NMDA receptor (NMDAR) is a heteromultimeric channel comprising the ubiquitous NR1 subunit and at least one regionally localized NR2 subunit. Here we report the characterization of a regulatory NMDAR subunit, NR3A (formerly termed NMDAR-L or chi-1), which is expressed primarily during brain development. NR3A co-immunoprecipitates with receptor subunits NR1 and NR2 in cerebrocortical extracts. In single-channel recordings from Xenopus oocytes, addition of NR3A to NR1 and NR2 leads to the appearance of a smaller unitary conductance. Genetic knockout of NR3A in mice results in enhanced NMDA responses and increased dendritic spines in early postnatal cerebrocortical neurons. These data suggest that NR3A is involved in the development of synaptic elements by modulating NMDAR activity.

Immunocytochemical localization of calmodulin and a heat-labile calmodulin-binding protein (CaM-BP80) in basal ganglia of mouse brain

Antisera to calmodulin, a Ca2%-dependent modulator protein, and a heat-labile calmodulin-binding protein have been used to localize these proteins in mouse caudate-putamen. The two proteins appear to be located at identical sites in this brain area. At the light microscopic level, calmodulin and calmodulin-binding protein are found within the cytoplasm and processes of large cells. At the electron microscopic level the proteins are associated with neuronal elements only, primarily at postsynaptic sites within neuronal somata and dendrites. Within the dendrites the immunocytochemical label is associated predominantly with the postsynaptic density and dendritic microtubules. These results are in accord with recent biochemical and immunihistochemical studies of calmodulin in brain and in dividing cells. Thus, calmodulin and the heat-labile calmodulin-binding protein may play a role in the nervous system at the site of neurotransmitter action and at the level of microtubular function.

Th1 and Th2 cytokine mRNA profiles in childhood nephrotic syndrome: evidence for increased IL-13 mRNA expression in relapse

Idiopathic nephrotic syndrome of childhood is thought to be associated with T lymphocyte dysfunction often triggered by viral infections, with the production of circulating factor(s) resulting in proteinuria. In view of the conflicting evidence of T cell activation and Th1 or Th2 pattern of cytokine synthesis in this disease, this study examined the mRNA expression of interleukin-2 (IL-2), interferon-gamma, IL-4, and IL-13 from CD4+ and CD8+ T cells in steroid-responsive nephrotic patients in relapse and remission. Fifty-five children with steroid-responsive nephrotic syndrome were included in this study, together with 34 normal controls and 24 patient controls with viral infections. RNA was isolated from purified CD4+ or CD8+ cells from peripheral blood and subjected to reverse transcription-PCR. Cytokine mRNA expression was measured semiquantitatively, and a cytokine index was derived from densitometric readings, with cyclophilin as the housekeeping gene. Both cross-sectional and paired data showed an increased CD4+ and CD8+ IL-13 mRNA expression in patients with nephrotic relapse as compared to remission, normal, and patient controls (P < 0.008). This was also associated with increased cytoplasmic IL-13 expression in phorbol myristate acetate/ionomycin-activated CD3+ cells (6.66+/-3.39%) from patients with nephrotic relapse compared to remission (2.59+/-1.35%) (P < 0.0001). However, there was no significant difference in CD4+ or CD8+ IL-2, interferon-gamma and IL-4 mRNA expression. IL-13 is an important T cell cytokine with anti-inflammatory and immunomodulatory functions on B cells and monocytes. It is conceivable that IL-13 may act on monocytes to produce vascular permeability factor(s) involved in the pathogenesis of proteinuria in patients with relapse nephrotic syndrome.

Calmodulin activates NAD kinase of sea urchin eggs: an early event of fertilization

NAD kinase, one of the first enzymes activated after fertilization of sea urchin eggs, is regulated by Ca2+ and calmodulin in vitro. The evidence is the requirement for low amounts of Ca2+ (Kd for Ca2+ of 4 x 10(-7) M) and the dissociation of a heat-stable activator from the enzyme which is similar to calmodulin on the basis of radioimmunoassay, activation of bovine brain phosphodiesterase and coelectrophoresis of a major protein of the activator fraction with bovine calmodulin. Also, the calcium stimulation of the enzyme is prevented by trifluoperazine, an inhibitor of calmodulin-associated reactions. In vivo studies show that the enzyme is activated by artificial parthenogenesis regimes that increase cytosolic Ca2+, but not by ammonia activation which only partially activates eggs and bypasses the Ca2+-rise step. These in vitro and in vivo studies indicate that calmodulin is part of the linkage between the rise in Ca2+ at fertilization and the turning on of egg metabolism.

A high-density SNP genotyping array for Brassica napus and its ancestral diploid species based on optimised selection of single-locus markers in the allotetraploid genome

The Brassica napus Illumina array provides genome-wide markers linked to the available genome sequence, a significant tool for genetic analyses of the allotetraploid B. napus and its progenitor diploid genomes. A high-density single nucleotide polymorphism (SNP) Illumina Infinium array, containing 52,157 markers, was developed for the allotetraploid Brassica napus. A stringent selection process employing the short probe sequence for each SNP assay was used to limit the majority of the selected markers to those represented a minimum number of times across the highly replicated genome. As a result approximately 60 % of the SNP assays display genome-specificity, resolving as three clearly separated clusters (AA, AB, and BB) when tested with a diverse range of B. napus material. This genome specificity was supported by the analysis of the diploid ancestors of B. napus, whereby 26,504 and 29,720 markers were scorable in B. oleracea and B. rapa, respectively. Forty-four percent of the assayed loci on the array were genetically mapped in a single doubled-haploid B. napus population allowing alignment of their physical and genetic coordinates. Although strong conservation of the two positions was shown, at least 3 % of the loci were genetically mapped to a homoeologous position compared to their presumed physical position in the respective genome, underlying the importance of genetic corroboration of locus identity. In addition, the alignments identified multiple rearrangements between the diploid and tetraploid Brassica genomes. Although mostly attributed to genome assembly errors, some are likely evidence of rearrangements that occurred since the hybridisation of the progenitor genomes in the B. napus nucleus. Based on estimates for linkage disequilibrium decay, the array is a valuable tool for genetic fine mapping and genome-wide association studies in B. napus and its progenitor genomes.

Balance and physical impairments after stroke

OBJECTIVE

To investigate the relationship among laboratory and clinical balance measures and physical impairments.

DESIGN

A descriptive correlational study.

SETTING

Research laboratory.

PARTICIPANTS

Thirty subjects with stroke, recruited through convenience sampling.

MAIN OUTCOME MEASURES

Postural sway was calculated in terms of center of pressure (COP) parameters including spectral characteristics. Clinical balance was measured using the Balance Scale. The assessed physical impairments included stages of lower limb motor recovery, ankle proprioception, and passive dorsiflexion range of the involved limb.

RESULTS

The Balance Scale was correlated with COP speed (r = -.57), COP root mean square speed (r = -.50), and COP mean frequency (r = -.50) in the anterior-posterior direction only. Moderate to high correlations were found among most of the COP parameters except spectral characteristics. Significant differences in postural sway were found among different stance in eyes-open (p = .00 to .02) and eyes-closed conditions (p = .00 to .04). Subjects with impaired ankle proprioception had significantly increased postural sway and decreased Balance Scale scores when compared with the subjects with intact ankle proprioception.

CONCLUSIONS

Some of the clinical and laboratory balance assessments were related, indicating that some components of the tests are similar, but some measured different aspects of balance. Postural sway was related to visual condition, stance position, and proprioception.

Leptin and inflammation-associated cachexia in chronic kidney disease

Leptin is an adipocyte-derived hormone that acts as a major regulator of food intake and energy homeostasis. It circulates both as a free and as a protein-bound entity. Leptin is released into the blood in proportion to the amount of body fat and exerts sustained inhibitory effects on food intake while increasing energy expenditure. The leptin receptor belongs to the class I cytokine receptor superfamily and possesses strong homology to the signal-transducing subunits of the IL-6 receptor. The hypothalamic melanocortin system, and specifically the melanocortin-4 receptor (MC-4R), is critical in mediating leptin's effect on appetite and metabolism. Serum leptin concentrations are elevated in patients with chronic kidney disease (CKD) and correlate with C-reactive protein levels suggesting that inflammation is an important factor that contributes to hyperleptinemia in CKD. Hyperleptinemia may be important in the pathogenesis of inflammation-associated cachexia in CKD. We showed that experimental uremic cachexia was attenuated in db/db mice, a model of leptin receptor deficiency. Nephrectomy in these animals did not result in any change in weight gain, body composition, resting metabolic rate, and efficiency of food consumption. Furthermore, experimental uremic cachexia could be ameliorated by blocking leptin signaling through the hypothalamic MC-4R. MC-4R knockout mice or mice administered the MC-4R and MC-3R antagonist, agouti-related peptide, resisted uremia-induced loss of lean body mass and maintained normal basal metabolic rates. Thus, melanocortin receptor antagonism may provide a novel therapeutic strategy for inflammation-associated cachexia in CKD.

The UK IBDQ-a British version of the inflammatory bowel disease questionnaire. development and validation

Measurement of health-related quality of life (HRQL) is becoming more important in studies of patients with inflammatory bowel disease. The McMaster IBDQ is the most widely used HRQL instrument for these patients. However, its use with patients in the United Kingdom has not been validated. This study develops and validates a UK version of the McMaster IBDQ (UK IBDQ). The UK IBDQ was tested with two samples of patients for its reliability, validity, reproducibility, and responsiveness. The first sample consisted of 180 patients participating in a randomized clinical trial. The second was recruited from members of the National Association for Colitis and Crohns Disease. Reliability of the subscales and the summary score of the UK IBDQ is demonstrated by Cronbach's alpha and item-total correlations. Their validity is demonstrated by their correlations with SF-36 subscales and an empirical index of disease activity. Good intraclass correlations and responsiveness ratios show their reproducibility and responsiveness. The findings support the reliability, validity, reproducibility, and responsiveness of the UK IBDQ and its acceptability to patients in UK.

High levels of a heat-labile calmodulin-binding protein (CaM-BP80) in bovine neostriatum

Bovine brain contains a heat-labile, 80,000-dalton calmodulin-binding protein (CaM-BP80) which inhibits the calmodulin-dependent activities of cyclic 3',5'-nucleotide phosphodiesterase, adenylate cyclase, and Ca2+-ATPase in vitro. CaM-BP80 is composed of two polypeptides (60,000 and 18,500 daltons) present in a 1:1 ratio. An antibody directed against CaM-BP80 was raised in rabbits, and a radioimmunoassay was developed, having a sensitivity of 60 fmol of CaM-BP80. Using the radioimmunoassay, we determined the levels of CaM-BP80 in various bovine tissues. The protein was found primarily in the brain, present in particularly high levels in the neostriatum. These results, together with immunohistochemical localization of CaM-BP80 at the postsynaptic densities and the microtubules of postsynaptic dendrites [Wood, J.G., Wallace, R., Whitaker, J., & Cheung, W.Y. (1980) J. Cell Biol. 84, 66-76], suggest that the protein may have a role in the cerebrum at the site of neurotransmitter action and at the level of microtubular function.

Irreversible electroporation for unresectable hepatocellular carcinoma: initial experience and review of safety and outcomes

The aims of this study were to evaluate the safety, feasibility and tumour response of _irreversible electroporation, a non-thermal ablation technique, for the treatment of unresectable hepatocellular carcinoma. The endpoints were safety and local treatment efficacy. Patients with unresectable tumours and tumours not amenable for radiofrequency _ablation because of their vicinity to organs vulnerable to thermal damage such as the bowel or because they were close to large blood vessels that would limit efficacy of ablation due to the heat sink effect were treated with irreversible electroporation using percutaneous _ultrasound and/or computed tomography guided electrode placement between November 2008 and _December 2009. Early, late, minor and major complications were recorded. Tumour response was determined on triphasic helical computed tomography follow-up at one month, then every three months post-procedure. Eleven patients received IRE therapy to 18 HCC lesions (Mean diameter 2.44 ± 0.99 cm; range 1.0-6.1 cm) with five patients having more than one treated HCC. Mean follow-up was 18 months (range 14-24 months). Six patients required repeat treatments for local residual or recurrent disease; two of these also had IRE for distant intrahepatic recurrence. No serious complications were observed despite seven lesions lying adjacent to important structures or organs. Four patients developed transient urinary retention and seven developed transient local post-procedure pain. After IRE therapy, 13 (72%) lesions were completely ablated with 93% success for lesions ≤ 3 cm (13/14). The local recurrence-free period was 18 ± 4 months and the distance recurrence free period was 14 ± 6 months. These preliminary results suggest that IRE is a safe and feasible technique for local ablation of HCC, particularly for lesions less than 3 cm. No major complications were encountered during this study even for tumours close to essential structures or organs.

A phase I study of single-agent nilotinib or in combination with imatinib in patients with imatinib-resistant gastrointestinal stromal tumors

PURPOSE

To study the safety, tolerability, and pharmacokinetics of the selective tyrosine kinase inhibitor nilotinib as a single agent or in combination with imatinib in patients with advanced imatinib-resistant gastrointestinal stromal tumors.

EXPERIMENTAL DESIGN

A phase I intercohort dose-escalation trial was done in patients who received either (a) single agent nilotinib 400 mg twice daily or (b) escalating doses of nilotinib (200 mg once daily, 400 mg qd, or 400 mg bid) plus imatinib 400 mg bid (10- and 14-hour interval daily), or (c) nilotinib 400 mg bid plus imatinib 400 mg qd. Safety, pharmacokinetics, and tumor assessments were done.

RESULTS

Oral clearance (CL/F) of nilotinib was similar across the combination groups (mean CL/F, 19.1-25.6 L/h), and lower than in the single-agent cohort (mean CL/F, 35.6 L/h). A linear relationship between nilotinib daily dose and peak concentration was observed in the combination cohorts. Observed adverse events (AE) were mostly nonhematologic. Frequently reported AEs were rash (40%), fatigue (38%), abdominal pain (36%), and nausea (36%). Severe AEs (grade 3 or 4) included abdominal pain (13%) and rash (9%), the latter mainly with the combination. Thirty-eight patients had stable disease and two patients achieved partial response with a median progression-free survival of 134 days for the entire group.

CONCLUSIONS

Nilotinib alone or in combination with imatinib was well tolerated overall and showed clinical activity in imatinib-resistant gastrointestinal stromal tumor patients. This phase I trial identified single-agent nilotinib 400 mg bid or combined with imatinib 400 mg qd as possible phase II doses for further evaluation.

Maternal anxiety and feelings of control during labour: a study of Chinese first-time pregnant women

OBJECTIVE

to explore and examine the relationship between maternal anxiety levels and feelings of control during labour among Hong Kong Chinese first-time pregnant women.

DESIGN

an exploratory descriptive correlation design. Data were collected on three occasions: during latent phase of labour, during active phase of labour and within 24-48 hrs after delivery.

SETTING

an obstetric unit of a public teaching hospital in Hong Kong.

PARTICIPANTS

a convenience sample of 90 Hong Kong Chinese first-time mothers.

MEASUREMENTS AND FINDINGS

the Labour Agentry Scale (LAS) is a self-report scale designed to measure feelings of control during childbirth. A Visual Analogue Scale for anxiety (VAS-A) was used to measure women's self-reported level of anxiety during labour. Pearson Product Moment Correlation coefficient test indicated a significant negative relationship between the feelings of control and maternal anxiety during labour. No statistical relationships were detected between women's attendance at antenatal classes and feelings of control during labour.

KEY CONCLUSIONS

the study showed a significant negative relationship between maternal anxiety and feelings of control during labour.

IMPLICATIONS FOR PRACTICE

midwives should work with women to enhance their personal control during labour and satisfaction with their birth. The insignificant relationship between attendance at antenatal classes and feelings of control suggests the need to evaluate the content of childbirth education in order to empower women's control during labour.