Implication of the serotoninergic system in the decreased ACTH response to stress after lesion of the amygdaloid central nucleus

1. The present study was designed to ascertain the possible implication of the serotoninergic system and the central amygdaloid nucleus in the control of ACTH secretion in response to immobilization stress.

2. The response to immobilization stress of intact and lesioned animals was studied by monitoring the plasma and pituitary ACTH concentration and the activity of the serotoninergic system within specific hypothalamic and amygdaloid nuclei.

3. Bilateral lesions of the central nucleus of the amygdala significantly decreased the secretion of ACTH in response to immobilization. Moreover, the serotoninergic activity in most of the hypothalamic and in all the amygdaloid nuclei studied was greatly increased. A 60-min immobilization stress prevented this increase in the hypothalamic nuclei but not in the amygdala.

4. These results indicate that the central nucleus of the amygdala participates in the regulation of ACTH secretion in response to immobilization stress. Furthermore, they substantiate the hypothesis of a participation of the serotoninergic system in limbic areas, particularly in nuclei which contain neurons possessing glucocorticoid receptors such as the medial, basomedial and cortical amygdaloid nuclei.     

Beta-lactam antibiotic prevents tolerance to the hypothermic effect of a kappa opioid receptor agonist

Beta-lactam antibiotics are the only clinically approved drugs which directly increase glutamate uptake. They activate the glutamate transporter subtype 1 (GLT-1), the protein responsible for 90% of glutamate uptake in the mammalian brain. The capacity of GLT-1 to clear extracellular glutamate suggests that glutamate transporter activators be explored for therapeutic approaches to clinical conditions caused by increased glutamatergic transmission. One of the most common drug effects mediated by increased glutamatergic signaling is opioid tolerance. Therefore, we tested the hypothesis that a beta-lactam antibiotic (ceftriaxone), by increasing glutamate uptake, prevents tolerance to hypothermia induced by a kappa opioid receptor agonist (U-50,488H). A single injection of U-50,488H (20mg/kg, s.c.) caused significant hypothermia in rats. Tolerance to the hypothermic effect of U50,488H was induced by injecting U50,488H (20mg/kg) twice daily for 7days. Pretreatment with ceftriaxone (200mg/kg, i.p.) for 7days did not alter the acute hypothermic response to U50,488H (20mg/kg) but did prevent tolerance to U50,488H-induced hypothermia. Central administration of dl-threo-beta-benzyloxyaspartic acid (TBOA) (0.2mumol, i.c.v.), a glutamate transporter inhibitor, abolished the effect of ceftriaxone. These results identify a functional interaction between ceftriaxone and U50,488H in vivo and provide pharmacological evidence that a beta-lactam antibiotic abolishes tolerance to hypothermia induced by a kappa opioid receptor agonist.     

Estimation of Duloxetine Hydrochloride in Pharmaceutical Formulations by RP-HPLC Method

Simple, specific, accurate and precise method, namely, reverse phase high performance liquid chromatography was developed for estimation of duloxetine HCl in pharmaceutical formulations. For the high performance liquid chromatography method, Phenomenox C-18, 5 μm column consisting of 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.01M 5.5 pH phosphate buffer: acetonitrile (60:40 v/v) and final pH adjust to 5.5±0.02 with phosphoric acid was used. The flow rate was 1.2 ml/min and effluent was monitored at 231 nm. The retention time was 5.61 min. The method was validated in terms of linearity, accuracy and precision. The linearity curve was found to be linear over 0.25-4 μg/ml. The limit of detection and limit of quantification were found to be 0.10 and 0.25 μg/ml respectively. The proposed method was successfully used to determine the drug content of marketed formulations.     

Update on ventricular assist devices

Ventricular assist devices serve as a valuable adjunct to therapy in the setting of profound heart failure. The two largest patient groups--postcardiotomy and those being bridged to transplant--show an average 40-50% survival rate after ventricular assist. Several devices exist including centrifugal, pneumatic, and electrical pumps. Options for ventricular assist include right (RVAD), left (LVAD), and biventricular (BiVAD) support. Knowledge regarding the devices and the pathophysiology of severe heart failure is crucial for the critical care nurse caring for these patients. Critical care nursing interventions for bleeding, renal failure, infection, and other complications will be outlined.     

Imaging Response and Residual Metastatic Axillary Lymph Node Disease after Neoadjuvant Chemotherapy for Primary Breast Cancer

Background

Although surgical management of the breast after neoadjuvant chemotherapy (NAC) may be governed by treatment response, axillary management continues to be determined by stage at presentation. Axillary ultrasound (AUS) with fine-needle aspiration (FNA) is used to detect lymph node (LN) metastases for pre-NAC staging, but imaging assessment of treatment response in the axilla remains undefined. We evaluated post-NAC axillary imaging and surgical pathology to understand how imaging might direct axillary surgery.

Methods

We evaluated pre- and post-NAC axillary imaging and clinicopathologic data in 272 patients who received NAC for primary breast cancer and underwent operation at our institution from 2010 to 2012. Treatment response on imaging was categorized as complete (CR), partial (PR), and none/progression (NR).

Results

Pre-NAC axillary staging classified patients as AUS negative/no FNA (n = 61), FNA/LN negative (n = 42), and FNA/LN positive (n = 169). Post-NAC axillary imaging included AUS (n = 146), MRI (n = 139), and PET-CT (n = 38). At operation, 128 of 272 patients (47 %) were LN positive: 23.3 % (24 of 103) of cN0 and 61.5 % (104 of 169) of cN1-AUS/FNA-positive patients at presentation. Of the 65 cN1-ypN0 patients, 58.1 % (25 of 43) had an imaging CR by US, 58.6 % (17 of 29) by MRI, and 84.6 % (11 of 13) by PET-CT. The sensitivity of post-NAC axillary imaging in detecting persistent LN metastases for cN1-AUS/FNA-positive patients was 69.8 % for US, 61.0 % for MRI, and 63.2 % for PET-CT.

Conclusions

Performance characteristics of AUS, MRI, and PET-CT, while informative, were inadequate to preclude surgical axillary staging of in breast cancer patients after NAC. Whether this information might be used to tailor surgical and postsurgical treatment requires further investigation.     

Association Between Falls and Brain Subvolumes: Results from a Cross-Sectional Analysis in Healthy Older Adults

Falls are a consequence of gait instability. Cortical and subcortical abnormalities have been associated with gait instability but not yet with falls. This study aims to compare the global and regional brain subvolumes between healthy older fallers and non-fallers. A total of 77 healthy older individuals (23 fallers and 54 non-fallers, 69.8 ± 3.5 years; 45.5 % female) were included in this study using a cross-sectional design. Based on an a priori hypothesis, the following brain subvolumes were quantified from three-dimensional T₁-weighted MRI using FreeSurfer software: total white matter abnormalities, total white matter, total cortical and subcortical gray matter, hippocampus, motor cortex, somatosensory cortex, premotor cortex, prefrontal cortex and parietal cortex volumes. Gait performances were also recorded. Age, sex, body mass index, comorbidities, use of psychoactive drugs, far-distance visual acuity, lower-limb proprioception, depressive symptoms and cognitive scores (Mini-Mental State Examination, Frontal Assessment Battery) were used as covariates. Fallers have more frequently depressive symptoms (P = 0.048), a lower far distance visual acuity (P = 0.026) and a higher coefficient of variation of stride time (P = 0.008) compared to non-fallers. There was a trend to greater subvolumes for the somatosensory cortex (P = 0.093) and the hippocampus (P = 0.060) in the falls group. Multiple logistic regressions showed that subvolumes of the somatosensory cortex and the hippocampus (P < 0.042) were increased in fallers compared to non-fallers, even after adjustment for clinical and brain characteristics. The greater subvolumes of the somatosensory cortex and hippocampus reported in fallers compared to non-fallers suggests a possible brain compensatory mechanism involving spatial navigation and integration of sensory information.     

Subtractive cloning: new genes for studying inflammatory disorders

Understanding of the biology of interaction between pathogens and host is the central question in studying inflammatory disorders. Subtractive DNA cloning is one of the most efficient and comprehensive methods available for identifying eukaryotic genes regulated under specific physiological conditions, including inflammation and host response. Here we explore the utility of subtractive DNA cloning and describe suppression subtractive hybridization (SSH), a polymerase chain reaction (PCR)-based DNA subtraction method that has been developed and evolved in our labs over several years. The SSH method possesses a number of advantages as compared to other subtractive cloning techniques, making it one of the most adventitious methods for cloning differentially expressed genes. Besides isolation of differentially expressed eukaryotic mRNAs, subtractive DNA cloning can be used to identify genes that are differentially expressed between diverse bacterial species. These genes can be of great interest, as some may encode strain-specific traits such as drug resistance, or bacterial surface proteins involved in determining the virulence of a particular strain. Other genes may be useful as markers for epidemiological or evolutionary studies. To demonstrate the potential of the SSH technique, we describe here the comprehensive characterization of 2 SSH subtracted libraries constructed in our laboratories. One library was created using eukaryotic cDNA subtraction and is specific for mRNAs up-regulated in CD25 positive cells from mouse lymph nodes as compared to CD25 negative cells. The second subtracted library is specific for a methicillin-resistant Staphylococcus aureus bacterial strain, but not in a methicillin-sensitive strain. The bacterial genomes of these 2 strains have been completely sequenced and this second library provides an excellent reference for testing the ability of SSH to recover all strain-specific gene content. The analysis of these 2 subtracted libraries serves as the basis for a discussion of the strength and limitations of the SSH technique. We will also compare and contrast subtractive DNA cloning to other current technologies used to isolate differentially expressed genes.