Agonist-induced internalization of corticotropin-releasing factor receptors in noradrenergic neurons of the rat locus coeruleus

Corticotropin-releasing factor (CRF) acts within the locus coeruleus (LC), to modulate activity of the LC-norepinephrine (NE) system. Combining molecular and cellular approaches, we demonstrate CRF receptor (CRFr) mRNA expression in Sprague-Dawley rat LC and provide the first in vivo evidence for agonist-induced internalization of CRFr. CRFr mRNA was detected in LC micropunches by RT-PCR. In dual labelling immunofluorescence studies, tyrosine hydroxylase (TH) containing neurons exhibited CRFr labelling. At the ultrastructural level, immunogold-silver labelling for CRFr was localized to the plasma membrane of TH-immunoperoxidase labelled dendrites. CRF (100 ng) injection into the LC produced a robust neuronal activation that peaked 10-15 min after injection and was maintained for the duration of the recording. This was associated with CRFr internalization in LC neurons that was apparent at 5 and 30 min after injection. By 5 min after injection the ratio of cytoplasmic to total dendritic CRFr-labelling was 0.81 +/- 0.01 in rats injected with CRF and 0.59 +/- 0.02 in rats injected with artificial cerebrospinal fluid (ACSF; P < 0.0001). Enhanced internalization of CRFr was maintained at 30 min after CRF injection, with the ratio being 0.86 +/- 0.02 for CRF-injected cases and 0.57 +/- 0.03 for ACSF-injected cases (P < 0.0001). Internalized CRFr was associated with early endosomes, indicative of degradation or recycling. Agonist-induced CRFr internalization in LC neurons may underlie acute desensitization to CRF or stress. This process may be a pivotal target by which stressors or pharmacological agents regulate the sensitivity of the LC-NE system to CRF and subsequent stressors.     

Cognitive dysfunction in patients with relapsing-remitting multiple sclerosis

Cognitive dysfunction is considered one of the clinical markers of multiple sclerosis (MS). However, in the literature there are inconsistent reports on the prevalence of cognitive dysfunction, and separate data for the relapsing-remitting (RR) type of the disease are not always presented. In this study, we submitted 461 RRMS patients to a battery of neuropsychological tests to investigate their impairment in various cognitive domains. As a consequence of the exclusion criteria, the sample is not fully representative of the entire population of RRMS patients. In this selected sample, when only the eight scores of a core battery (Mental Deterioration Battery) were considered (with respective cutoffs), it emerged that 31% of the patients were affected by some degree of cognitive deficit. In particular, 15% had mild, 11.2% moderate and 4.8% had severe impairment. Information processing speed was the most frequently impaired area, followed by memory. When two other tests (SDMT and MCST) were added and cognitive domains were considered, it emerged that 39.3% of the patients were impaired in two or more domains. When four subgroups were obtained by means of cluster analysis and then compared, it emerged that information processing speed and memory deficits differentiated the still cognitively unimpaired from the mildly impaired MS patients. Significant associations were found between cognitive and clinical characteristics. However, due to the large sample size, clinically irrelevant relationships may also have emerged. Even with the limitations imposed by the sample selection and the possible underestimation of the prevalence and severity of cognitive dysfunction, these results seem to provide further evidence that information processing speed deficit may be an early and important marker of cognitive impairment in MS patients.     

Midterm outcome of radiofrequency thermal ablation for symptomatic uterine myomas

Background Over the past decade an increasing demand for uterine-sparing treatment to manage symptomatic uterine myomas has become apparent in women’s health care. A preliminary report showed that radiofrequency ablation (RFA) of uterine fibroids under laparoscopic guidance was a safe and effective minimally invasive approach with encouraging short-term results. The purpose of this study was to evaluate the midterm outcomes of radiofrequency ablation (RFA) of uterine myomas in terms of durability of symptom control and level of health-related quality of life. Methods Consecutive women with symptomatic uterine myomas, no plans for future pregnancy, and who declined hysterectomy were offered RFA ablation of uterine fibroids under laparoscopic guidance. Only 25 patients who completed at least the one-year follow-up assessment were included in the study group. Follow-up evaluations were scheduled at 1, 3, 6, 9, and 12 months and thereafter annually following the procedure. Improvement in myoma-related symptoms and impact on quality of life were assessed using a validated questionnaire (UFS-QOL). Results The median number of myomas treated per patient was 1 (range = 1–3). The median baseline volume of the dominant myoma was 76.8 cm³ (range = 14.8–332.8). No intraoperative or postoperative complications occurred. The median follow-up time was 24 months, with nine women completing three years of follow-up. The median reduction in myoma volume was 68.8% and 77.9% at six months and one year, respectively. No further change in fibroid size was observed at two years and three years. One year after the procedure, one woman (4%) underwent hysterectomy for recurrence of fibroid-related symptoms. Quality-of-life measures showed significant and durable improvement compared with baseline. Conclusions RFA of symptomatic fibroids seems a valuable alternative to major surgery, with durable symptom relief for most patients and a low chance of recurrence at midterm.     

Haemostatic efficacy and safety of bolus and continuous infusion of recombinant factor VIIa are comparable in haemophilia patients with inhibitors undergoing major surgery. Results from an open-label, randomized, multicenter trial

Bolus infusion (BI) recombinant factor VIIa (rFVIIa) administration is safe and effective in the surgical management of haemophilia patients with inhibitors but has not been compared directly with continuous infusion (CI). We conducted an open-label, randomized, multicenter trial comparing the efficacy and safety of rFVIIa administered by BI or CI for the surgical management of haemophilia A or B patients with inhibitors to FVIII or FIX. Safety was compared with that of a control group of non-inhibitor patients receiving FVIII or FIX concentrates for major surgery. All inhibitor subjects received an initial bolus dose of 90 microg/kg rFVIIa and were then randomly assigned to BI (n = 12) or CI (n = 12). The BI group received 90 microg/kg rFVIIa every two hours (h) during surgery through day 5, then every four hours for days 6-10. The CI group received 50 microg/kg/h rFVIIa through day 5, then 25 mg/kg/h for days 6-10. The control group (n = 12) received FVIII or FIX per institutional protocols. Twenty-two major surgeries included orthopedic procedures on the knee (n = 13), hip (n = 3), and abdominal/pelvis procedures (n = 4). One patient with an autoimmune FVIII inhibitor randomized to the BI arm was excluded from efficacy analysis. Haemostatic efficacy of rFVIIa in each group was comparable: effective in 8/11 and 9/12 subjects in the BI and CI arms, respectively, and ineffective in three subjects in each arm. Serious adverse events were related to continued or increased bleeding. In conclusion, haemostatic efficacy and safety of BI and CI of rFVIIa are comparable for the surgical management of haemophilia subjects with inhibitors.     

Age effects on hippocampal structural changes in old men: the HAAS

Understanding the variability of the hippocampus in human brain research is essential. The effect of age on the hippocampus has been explored in several studies that have been focused on either normal aging or neural degeneration. Shape analysis of magnetic resonance imaging (MRI) provides morphological measures for brain structures. This study further investigates the age effects on hippocampal morphology in three groups (104 normal controls, 24 Alzheimer's disease (AD) and 14 vascular dementia (VaD) patients). By utilizing a parametric shape analysis of hippocampal MRI scans, each individual distance map is generated and analyzed statistically. Specifically, after eliminating similarity parameters (rotation, translation, and scaling) effects for each hippocampus, an individual distance map is generated from parametric hippocampal surfaces and medial axes. Then statistical methods, including regression, and permutation tests, are applied to detect the differences in hippocampal distance maps and volumes under the effect of age in each group. Statistical analyses reveal that the loss of hippocampal volume and changes in shape are more significantly related to aging in the control group than in AD/VaD. The results also show that the asymmetry of hippocampus in healthy subjects is greater than that in either of the disease groups. Our study shows that 3D statistical shape analysis could enhance the understanding of age effects on local areas of hippocampi. However, the sample sizes of disease groups are relatively low; further studies with more AD/VaD data are needed.     

Rapamycin Reduces Proteinuria and Renal Damage in the Rat Remnant Kidney Model

Rapamycin is an immunosuppressive drug used to prevent acute allograft rejection in solid organ transplantation. It shows less nephrotoxicity than calcineurin inhibitors. We evaluated the effect of rapamycin in rats undergoing 5/6 nephrectomy, a model of proteinuric and progressive renal failure. Fourteen days after surgery rats were randomized either to receive rapamycin or to remain untreated (control). Rats were humanely killed on day 91; serum creatinine, creatinine clearance, and proteinuria were assessed. Renal sections were stained with periodic acid-Schiff to evaluate glomerular volume (Gv), glomerulosclerosis (GS) and tubulointerstitial damage (TIS); we evaluated GS and TIS by Sirius red staining (SR). Epithelial-to-mesenchymal transition (EMT) was assessed by immunohistochemistry. Rapamycin affected neither serum creatinine nor creatinine clearance; it reduced Gv (controls, 5.9 ± 3.1 × 10⁶; rapamycin, 1.3 ± 0.7 × 10⁶ μm³) and proteinuria (control, 349 ± 146; rapamycin, 56 ± 27 mg/24 h; P < .05); rapamycin ameliorated GS (control, 78 ± 7; rapamycin, 36 ± 7%; P < .05; SR: control, 13.2 ± 3.5; rapamycin, 3.8 ± 1.0%; P < .05), and TIS (control, 3.25 ± 0.5; rapamycin, 1.0 ± 0.1; P < .05; SR: control, 29 ± 3; rapamycin, 11 ± 3%; P < .05). Rapamycin reduced αSMA (control, 3.25 ± 0.5; rapamycin, 1.0 ± 0.1; P < .05), VIM (control, 3.5 ± 0.6; rapamycin, 1.0 ± 1.4; P < .05), and CD68⁺ cells infiltration (control, 110 ± 43; rapamycin, 24 ± 1 cells; P < .05). Rapamycin slows the progression of renal damage in the rat remnant kidney and may represent a novel approach to the treatment of chronic kidney disease.     

A mechanistic and kinetic study of the beta-lactone hydrolysis of Salinosporamide A (NPI-0052), a novel proteasome inhibitor

The aim of the present study was to investigate the mechanism of aqueous degradation of Salinosporamide A (NPI-0052; 1), a potent proteasome inhibitor that is currently in Phase I clinical trials for the treatment of cancer and is characterized by a unique beta-lactone-gamma-lactam bicyclic ring structure. The degradation of 1 was monitored by HPLC and by both low- and high-resolution mass spectral analyses. Apparent first-order rate constants for the degradation at 25 degrees C were determined in aqueous buffer solutions (ionic strength 0.15 M adjusted with NaCl) at various pH values in the range of 1 to 9. Degradation kinetics in water and in deuterium oxide were compared as a mechanistic probe. The studies were performed at pH (pD) 4.5 at 25 degrees C. To further confirm the reaction mechanism, the degradation was also performed in (18)O-enriched water and the degradation products subjected to HPLC separation prior to mass spectral analysis. Solubility and stability in (SBE)(7m)-beta-cyclodextrin (Captisol) solutions were also determined. The hydrolytic degradation of 1, followed by both HPLC and LC/MS, showed that the drug in aqueous solutions gives a species with a molecular ion consistent with the beta-lactone hydrolysis product (NPI-2054; 2). This initial degradant further rearranges to a cyclic ether (NPI-2055; 3) via an intramolecular nucleophilic displacement reaction. The kinetic results showed that the degradation of 1 was moderately buffer catalyzed (general base) and the rate constants were pH independent in the range of 1-5 and base dependent above pH 6.5. No acid catalysis was observed. The kinetic deuterium solvent isotope effect (KSIE) was 3.1 (kH/kD) and a linear proton inventory plot showed that the rate-determining step involved only a single proton transfer. This suggested that a neighboring hydroxyl group (as opposed to a second water molecule) facilitated water attack at pD 4.5. Mass spectral analysis from the (18)O-labeling studies proved that the mechanism involves acyl-oxygen bond cleavage and not a carbonium ion mechanism. 1 is unstable in water (t(90%) 相似文献   

Panitumumab: the evidence of its therapeutic potential in metastatic colorectal cancer care

Introduction:

Colorectal cancer is the fourth most common malignant disease. Of newly diagnosed patients, 40% have metastatic disease at diagnosis, and approximately 25% of patients with localized disease at diagnosis will ultimately develop metastatic disease. The benefits of systemic chemotherapy in the treatment of metastatic colorectal cancer over best supportive care have been established. Panitumumab (ABX-EGF) is the first fully human monoclonal antibody developed for use in colorectal cancer that targets the extracellular domains of epidermal growth factor receptor.

Aims:

The goal of this article is to review the published evidence for the use of panitumumab in the treatment of metastatic colorectal cancer to define its therapeutic potential.

Evidence review:

The major evidence of panitumumab activity in colorectal cancer has appeared in meeting report abstracts. One phase II study in monotherapy, one in combination with chemotherapy, and one phase III study have included only patients with metastatic colorectal cancer.

Clinical potential:

To date, in phase II clinical studies panitumumab has demonstrated antitumor activity in advanced, refractory colorectal cancer. As monotherapy it resulted in a 10% response rate with 38% of patients having stable disease, and a 36% response rate with 46% stable disease when combined with chemotherapy. A phase III study indicates a clinically significant advantage of panitumumab as third-line monotherapy over best supportive care. Panitumumab appears to have a good tolerability profile, with no maximum tolerated dose yet defined.