PSNCBAM-1, a novel allosteric antagonist at cannabinoid CB1 receptors with hypophagic effects in rats

BACKGROUND AND PURPOSE: Rimonabant (Acomplia, SR141716A), a cannabinoid CB1 receptor inverse agonist, has recently been approved for the treatment of obesity. There are, however, concerns regarding its side effect profile. Developing a CB1 antagonist with a different pharmacological mechanism may lead to a safer alternative. To this end we have screened a proprietary small molecule library and have discovered a novel class of allosteric antagonist at CB1 receptors. Herein, we have characterized an optimized prototypical molecule, PSNCBAM-1, and its hypophagic effects in vivo. EXPERIMENTAL APPROACH: A CB1 yeast reporter assay was used as a primary screen. PSNCBAM-1 was additionally characterized in [35S]-GTPgammaS, cAMP and radioligand binding assays. An acute rat feeding model was used to evaluate its effects on food intake and body weight in vivo. KEY RESULTS: In CB1 receptor yeast reporter assays, PSNCBAM-1 blocked the effects induced by agonists such as CP55,940, WIN55212-2, anandamide (AEA) or 2-arachidonoyl glycerol (2-AG). The antagonist characteristics of PSNCBAM-1 were confirmed in [35S]-GTPgammaS binding and cAMP assays and was shown to be non-competitive by Schild analyses. PSNCBAM-1 did not affect CB2 receptors. In radioligand binding assays, PSNCBAM-1 increased the binding of [3H]CP55,940 despite its antagonist effects. In an acute rat feeding model, PSNCBAM-1 decreased food intake and body weight. CONCLUSIONS AND IMPLICATIONS: PSNCBAM-1 exerted its effects through selective allosteric modulation of the CB1 receptor. The acute effects on food intake and body weight induced in rats provide a first report of in vivo activity for an allosteric CB1 receptor antagonist.     

Prevention of Dystrophic Pathology in Severely Affected Dystrophin/Utrophin-deficient Mice by Morpholino-oligomer-mediated Exon-skipping

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder caused by mutations in the dystrophin gene that result in the absence of functional protein. Antisense-mediated exon-skipping is one of the most promising approaches for the treatment of DMD because of its capacity to correct the reading frame and restore dystrophin expression, which has been demonstrated in vitro and in vivo. In particular, peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) have recently been shown to induce widespread high levels of dystrophin expression in the mdx mouse model. Here, we report the efficiency of the PPMO-mediated exon-skipping approach in the utrophin/dystrophin double-knockout mouse (dKO) mouse, which is a much more severe and progressive mouse model of DMD. Repeated intraperitoneal (i.p.) injections of a PPMO targeted to exon 23 of dystrophin pre-mRNA in dKO mice induce a near-normal level of dystrophin expression in all muscles examined, except for the cardiac muscle, resulting in a considerable improvement of their muscle function and dystrophic pathology. These findings suggest great potential for PPMOs in systemic treatment of the DMD phenotype.     

The Evolution of Abdominal Compression in Cardiopulmonary Resuscitation

Objective: To review the history of external abdominal compression as an adjunct to cardiopulmonary resuscitation (CPR), tracking the development of five major themes over the course of the 20th century: 1) augmentation of peripheral resistance by physical means, 2) risk of hepatic injury with abdominal compression, 3) counterpulsation vs sustained compression, 4) the abdominal pump mechanism, and 5) contact compression techniques.
Methods: Literature retrieved from successive MEDLINE English-language searches was reviewed with a special emphasis on work and concepts highlighted by participants at the First Purdue Conference on Interposed Abdominal Compression-CPR, September 1992.
Results: External abdominal compression of one form or another has been studied as a means of resuscitation by many investigators throughout the 20th century. Experimental and clinical studies have shown generally consistent evidence of hemodynamic augmentation by abdominal compression during various forms of CPR. Recent advances include a modified theoretical understanding of hemodynamic mechanisms and demonstration of clinical potential in humans. Inconsistencies in published results may be due to differences in mechanical techniques of abdominal compression. Based on these studies, a modified manual technique for "contact compression" of the abdominal aorta is recommended.
Conclusions: A technique for left-of-center, angled compression of the abdominal aorta against the crest of the spine is recommended. Further well-supervised and controlled clinical trials using this standardized technique are warranted as a prelude to more widespread clinical application of abdominal compression in CPR.     

Homozygous mutations in a predicted endonuclease are a novel cause of congenital dyserythropoietic anemia type I

The congenital dyserythropoietic anemias are a heterogeneous group of rare disorders primarily affecting erythropoiesis with characteristic morphological abnormalities and a block in erythroid maturation. Mutations in the CDAN1 gene, which encodes Codanin-1, underlie the majority of congenital dyserythropoietic anemia type I cases. However, no likely pathogenic CDAN1 mutation has been detected in approximately 20% of cases, suggesting the presence of at least one other locus. We used whole genome sequencing and segregation analysis to identify a homozygous T to A transversion (c.533T>A), predicted to lead to a p.L178Q missense substitution in C15ORF41, a gene of unknown function, in a consanguineous pedigree of Middle-Eastern origin. Sequencing C15ORF41 in other CDAN1 mutation-negative congenital dyserythropoietic anemia type I pedigrees identified a homozygous transition (c.281A>G), predicted to lead to a p.Y94C substitution, in two further pedigrees of SouthEast Asian origin. The haplotype surrounding the c.281A>G change suggests a founder effect for this mutation in Pakistan. Detailed sequence similarity searches indicate that C15ORF41 encodes a novel restriction endonuclease that is a member of the Holliday junction resolvase family of proteins.     

Increased expression of intercellular adhesion molecule 1 on bile ducts in primary biliary cirrhosis and primary sclerosing cholangitis.

It has been suggested that immunological mechanisms involving lymphocyte-mediated damage are important in the characteristic bile-duct damage that occurs in primary biliary cirrhosis and primary sclerosing cholangitis. Because adhesion is necessary for the interaction of lymphocytes with their target structures, we have studied the expression of intercellular adhesion molecule 1, a ligand for the leukocyte adhesion receptor lymphocyte function-associated antigen 1 in the liver of patients with primary biliary cirrhosis and primary sclerosing cholangitis. Strong expression of intercellular adhesion molecule 1 was seen on interlobular bile ducts and proliferating bile ductules in both conditions. In primary biliary cirrhosis, medium-sized ducts, which are spared by the disease, were negative. Minimal bile-duct staining was seen in conditions in which bile-duct damage is not a major feature, such as nonbiliary cirrhosis and acute liver diseases. In patients with cirrhosis from any cause, strong expression of intercellular adhesion molecule 1 was detected on the periseptal hepatocytes adjacent to new connective tissue. The intensity of immunohistochemical staining was recorded using a semiquantitative visual scoring system that was subsequently validated quantitatively by confocal laser scanning microscopy. The expression/induction of intercellular adhesion molecule 1 on bile ducts may be important in the pathogenesis of bile-duct damage in primary biliary cirrhosis and primary sclerosing cholangitis and is further evidence to support an immune pathogenesis in these two conditions. Furthermore, the induction of intercellular adhesion molecule 1 on hepatocytes may be an important factor in the liver-cell damage and fibrosis that occur during the development of cirrhosis.     

A computer-based,automated, telephonic system to monitor patient progress in the home setting

In this report we describe an automated, telephonic system to monitor the progress of patients convalescing at home. The system includes a computerized central station that is capable of automated voice communication over the telephone, using voice reproduction, and touch-tone recognition. Peripheral hardware in multiple monitored homes need include only a touch-tone telephone, but may also be augmented by inexpensive, rudimentary diagnostic aids, such as a scale for body weight, a thermometer, or a blood pressure cuff and manometer. Current central hardware includes a NeXT computer, a fax modem, and a specialized telecommunications modem developed specifically for voice telecommunication using the NeXT. The central station acts like a robotic nurse in that it asks patients a series of questions and records the responses. The subjective questions to be asked are patient individualized and pre-selected by the physician from a question menu including items targeted specifically for the patient's disease or condition. In addition, clinical data such as body weight, blood pressure, and body temperature obtained from in-home diagnostic aids may be transmitted to the central station over the telephone using touch tones. The time-of-day and frequency of calling are pre-selectable, according to the patient's preference and clinical status. Data obtained by the central station can be easily accessed by the duty nurse via menu driven software. Reports depicting significant responses as a function of time are generated in graphical format to facilitate rapid identification of adverse trends. Hard copy reports can be dispersed directly by fax. Results from a pilot study show patients with cardiac disease readily use the system without difficulty or complaints. In one patient a five pound increase in body weight was detected, which prompted the patient's cardiologist to adjust his medication. In this way automated telephone follow-up can provide early detection of complications before they become severe, making the home environment safer and more secure for convalescence and contributing to reduced health-care costs.     

Endotracheal versus intravenous epinephrine during electromechanical dissociation with CPR in dogs

The dose-response curves of epinephrine given either IV or endotracheally (ET) were compared during resuscitation from electromechanical dissociation (EMD). Ten anesthetized dogs were subjected to a two-minute period of electrically induced ventricular fibrillation (VF) followed by defibrillation without CPR to produce EMD. Mechanical CPR was followed by injection of either ET or IV epinephrine. Successful response was defined as a return of pulsatile blood pressure within two minutes of drug administration. Using log-dose increments of epinephrine, experimental trials were repeated in each animal. The IV and ET median effective doses were 14 and 130 micrograms/kg, respectively. When the trials were successful, the time between drug administration and either arterial blood pressure increases or return of spontaneous circulation did not differ significantly for the ET and IV groups. These results show that the dosage for epinephrine delivered ET must be higher than the IV dosage to achieve the same response during CPR.     

Endothelial cell transformation in primary biliary cirrhosis: a morphological and biochemical study

There is increasing interest in the changes of the endothelial lining of the hepatic sinusoids during the development of chronic liver disease. In this study we looked for evidence of hepatic sinusoidal endothelial cell transformation and basement membrane production in patients with primary biliary cirrhosis. Morphological transformation to vascular-type endothelial cells, as evidenced by the development VIII-related antigen, was seen at the interface between portal tracts or fibrous septae and hepatic parenchyma; the most marked changes were observed in patients with established cirrhosis. Increased immunohistochemical staining for the basement membrane components type IV collagen and laminin was also found in a similar distribution. Raised serum levels of hyaluronic acid, a glycosaminoglycan metabolized by normal hepatic endothelial cells, were found in most patients and correlated strongly with advancing histological stage. Furthermore, significant positive correlations were found between serum hyaluronic acid and serum levels of laminin and type IV collagen. The unique structure of the normal endothelial lining of the hepatic sinusoids is important in the maintenance of hepatic function. Our data show that significant changes in endothelial cell structure and function occur in primary biliary cirrhosis and appear to be a contributing factor to the progression of the disease. Further studies are needed to determine the extent and importance of these changes in other forms of chronic liver disease.     

Structured gastroenterological intervention and improved outcome for patients with chronic gastrointestinal symptoms following pelvic radiotherapy

Purpose

Fifty percent of patients develop chronic gastrointestinal (GI) symptoms following pelvic radiotherapy that adversely affect quality of life. Fewer than 20 % are referred to a gastroenterologist. We aimed to determine if structured gastroenterological evaluation is of benefit to this patient group.

Methods

Sixty patients with GI symptoms at ≥6 months after radical pelvic radiotherapy were identified prospectively from oncology clinics in this service evaluation. Those requiring urgent investigation were excluded. Patients were assessed at baseline using patient-reported questionnaires: inflammatory bowel disease questionnaire (IBDQ), Vaizey incontinence questionnaire, and the Common Terminology Criteria for Adverse Events (CTCAE) pelvis questionnaire. Participants were referred for gastroenterological evaluation using an algorithmic approach. Further assessments were made at 3 and 6 months.

Results

Twenty men and 36 women with primary gynecological (31), urological (17), or lower GI (8) tumors were included (mean age, 58.5 years). Median time from radiotherapy to baseline assessment was 3.0 years. Multiple GI symptoms were reported (median, 8; range, 4–16) including frequency, urgency, loose stool, fecal incontinence, flatulence, bloating/distension, and rectal bleeding. Common diagnoses included radiation proctopathy, bile acid malabsorption, diverticulosis, and colonic polyps. Statistically significant improvements in all questionnaire scores between baseline and 6 months were found: IBDQ (p?=?0.014), Vaizey (p?<?0.0005), and CTCAE rectum-bowel subset (p?=?0.001).

Conclusions

Gastroenterological evaluation identifies significant, potentially treatable diagnoses in patients who develop chronic GI symptoms following pelvic radiotherapy. Some findings are incidental and unrelated to previous cancer treatment. Radiation-induced GI symptoms have historically been considered “untreatable.” We report the first data to show that structured gastroenterological assessment has the potential to improve outcome by identifying diagnoses and facilitating focused treatment.