Modulation of gastrointestinal function by MuDelta,a mixed μ opioid receptor agonist/ μ opioid receptor antagonist

BACKGROUND & PURPOSE

Loperamide is a selective µ opioid receptor agonist acting locally in the gastrointestinal (GI) tract as an effective anti-diarrhoeal but can cause constipation. We tested whether modulating µ opioid receptor agonism with δ opioid receptor antagonism, by combining reference compounds or using a novel compound (‘MuDelta’), could normalize GI motility without constipation.

EXPERIMENTAL APPROACH

MuDelta was characterized in vitro as a potent µ opioid receptor agonist and high-affinity δ opioid receptor antagonist. Reference compounds, MuDelta and loperamide were assessed in the following ex vivo and in vivo experiments: guinea pig intestinal smooth muscle contractility, mouse intestinal epithelial ion transport and upper GI tract transit, entire GI transit or faecal output in novel environment stressed mice, or four weeks after intracolonic mustard oil (post-inflammatory). Colonic δ opioid receptor immunoreactivity was quantified.

KEY RESULTS

δ Opioid receptor antagonism opposed µ opioid receptor agonist inhibition of intestinal contractility and motility. MuDelta reduced intestinal contractility and inhibited neurogenically-mediated secretion. Very low plasma levels of MuDelta were detected after oral administration. Stress up-regulated δ opioid receptor expression in colonic epithelial cells. In stressed mice, MuDelta normalized GI transit and faecal output to control levels over a wide dose range, whereas loperamide had a narrow dose range. MuDelta and loperamide reduced upper GI transit in the post-inflammatory model.

CONCLUSIONS AND IMPLICATIONS

MuDelta normalizes, but does not prevent, perturbed GI transit over a wide dose-range in mice. These data support the subsequent assessment of MuDelta in a clinical phase II trial in patients with diarrhoea-predominant irritable bowel syndrome.     

On-site adequacy evaluations performed by cytotechnologists: correlation with final interpretations of 5241 image-guided fine-needle aspiration biopsies

BACKGROUND:

Practice patterns regarding on‐site assessment of the adequacy of image‐guided fine‐needle aspiration biopsies (FNABs) vary among laboratories, but in many laboratories primary responsibility rests with the cytotechnologists. On‐site evaluation provides feedback on the need for additional passes and facilitates triaging of the specimen for time‐sensitive ancillary studies. Prior studies have suggested that cytotechnologists can assess the initially obtained specimens correctly, but they are few in number and limited by small size. The purpose of this study was to assess the frequency with which our cytotechnologists were able to correctly assess specimens as adequate using a large‐scale database that included a wide range of image‐guided FNABs.

METHODS:

The frequency that on‐site adequacy assessments of 5241 image‐guided FNABs were correct was determined by correlating the cytotechnologists' assessments of adequacy with the final cytologic interpretation. An adequacy assessment was considered correct if the FNAB was ultimately reported as satisfactory and unequivocally benign or malignant. An adequate reading on a case that was ultimately reported as unsatisfactory, atypical, or suspicious was deemed “incorrect.” The effect of imaging modality was also analyzed.

RESULTS:

Of 5241 FNABs, 2784 (53%) were interpreted as adequate on site. Of these, 2637 (95%) were correctly considered adequate. Of the common biopsy sites sampled, the adequacy assessments for liver FNABs demonstrated the highest frequency for being correctly considered adequate (97%) and those for kidney FNABs showed the lowest (90%). Imaging modality had no effect on accuracy.

CONCLUSIONS:

Cytotechnologists are almost always correct when assessing initial FNAB samples as adequate. Cancer (Cancer Cytopathol) 2012;. © 2011 American Cancer Society.     

The application of cytogenetics and fluorescence in situ hybridization to fine‐needle aspiration in the diagnosis and subclassification of renal neoplasms

BACKGROUND:

Percutaneous fine‐needle aspiration (FNA) cytology is an important diagnostic test for the evaluation and management of selected renal masses. Cytogenetic analysis of cytology specimens can serve as an adjunct for precise classification because certain tumors are associated with specific chromosomal aberrations. This study summarizes our experience with the application of conventional cytogenetics and fluorescence in situ hybridization (FISH) to renal FNA specimens.

METHODS:

All percutaneous renal FNAs performed during 2005 through 2008 were identified from the electronic pathology database. Results of cytogenetic and FISH analyses were correlated with the final diagnoses of the renal FNAs.

RESULTS:

A total of 303 renal FNAs were performed. During an onsite assessment, a portion of the cytology specimen was allocated for cytogenetic analysis in 74 cases. Karyotypic analysis or FISH was successful in 44 (59%) of these. Characteristic chromosomal abnormalities were observed in 27 cases. In 17 cases, a karyotype revealed a combination of trisomies/tetrasomies and in another 5 cases, FISH revealed trisomy 7 and 17, both of which are consistent with papillary renal cell carcinoma (RCC). Two cases showed 3p deletions consistent with clear cell RCC. Trisomy 3 was observed in 1 case of clear cell RCC. Monosomy 1 and 17 was observed in a case of papillary RCC comprised oncocytic cells. In 1 case of primary renal synovial sarcoma, FISH revealed a rearrangement at the SYT locus (18q11.2).

CONCLUSIONS:

Renal FNA specimens are amenable to analysis by cytogenetics and FISH in the diagnosis and subclassification of renal neoplasms. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.     

Spinocerebellar ataxia and hypergonadotropic hypogonadism associated with familial sensorineural hearing loss

Cerebellar ataxia has been described as being associated with hypogonadism for almost 100 years. In the majority of cases, hypogonadism is hypogonadotropic. The association of cerebellar ataxia with hypergonadotropic hypogonadism is a rare genetic disorder with a recessive mode of inheritance. Cerebellar ataxia and hypogonadism can also occur associated with a large spectrum of additional clinical manifestations, including mental retardation, sensorineural deafness, choroidal dystrophy, ectodermal dysplasia and short stature, and polyneuropathy. We report the case of a woman with early-onset spinocerebellar ataxia, primary amenorrhea due to hypergonadotropic hypogonadism, and late-onset sensorineural hearing loss. Additional family members from the father's side are affected with late-onset hearing loss, suggesting a dominant mode of inheritance.     

PAPULAR-PURPURIC GLOVES-AND-SOCKS SYNDROME

Background and Objective. Papular-purpuric gloves-and-socks syndrome (PPGSS) is a recently described dermatosis in which human parvovirus B19 (HPV B19) has been implicated as etiologic agent; however, it is suspected that PPGSS may be caused by various agents. This study was designed to survey the general characteristics of PPGSS and to determine the role of HPV B19 in its etiology. Methods. We analyzed data from 21 patients and examined serum samples from three new cases for various viruses. Results. The PPGSS displays a striking uniform clinical pattern. Histologic and immunofluorescence findings are nonspecific. Seroconversion of HPV B19 was reported in six cases and confirmed in two of our patients. In only one case was a possible causative role of Coxsackie virus B6 suggested consistently. Conclusions. The PPGSS represents a distinctive dermatosis and a manifestation of HPV B19 infection. Unlike erythema infectiosum, anti-HPV B19 antibodies seem to develop later after onset of the skin eruption and while viremia is still present.     

Incidence and Predictors of Permanent Pacemaker Requirement after Transcatheter Aortic Valve Implantation with a Self‐Expanding Bioprosthesis

Background: Previous reports have suggested the occurrence of cardiac conduction disorders and permanent pacemaker (PPM) requirement after transcatheter aortic valve implantation (TAVI). Based on a single‐center experience, we aim to assess the incidence of postprocedural conduction disorders, need for PPM, and its determinants after TAVI with a self‐expanding bioprosthesis. Methods: From August 2007 to October 2009, 32 consecutive patients underwent TAVI with the Medtronic CoreValve (MCV) System (Medtronic Inc., Minneapolis, MN, USA). Three patients paced at baseline and two cases of procedure‐related mortality were excluded. We analyzed the 12‐lead electrocardiogram at baseline, immediately after procedure and at discharge. Requirements for PPM were documented and potential clinical, electrophysiological, echocardiographic, and procedural predictors of PPM requirement were studied. Results: After TAVI, eight patients (29.6%) required PPM implantation due to high‐grade atrioventricular (AV) block. The prevalence of left bundle branch block increased from 13.8% to 57.7% directly after implantation (P = 0.001). Need for PPM was correlated to the depth of prosthesis implantation (r = 0.590; P = 0.001). At a cutoff point of 10.1 mm, the likelihood of pacemaker could be predicted with 87.5% sensitivity and 74% specificity and a receiver operator characteristic curve area of 0.86 ± 0.07 (P = 0.003). Of the seven patients with preexisting right bundle branch block (RBBB), four (57.1%) required PPM implantation after TAVI. Conclusions: High‐grade AV block requiring PPM implantation is a common complication following TAVI and could be predicted by a deeper implantation of the prosthesis. Patients with preexisting RBBB also seem to be at risk for the development of high‐grade AV block and subsequent pacemaker implantation. (PACE 2010; 1364–1372)     

Hyperhomocysteinemia and transplant coronary artery disease in cardiac transplant recipients

BACKGROUND: In cardiac transplant recipients, long-term survival may be limited by transplant coronary artery disease (TxCAD). Hyperhomocysteinemia (Hhcy) has been associated with vascular disease and is common in transplant recipients. The objective of this study was to determine the relationship between fasting homocysteine (Hcy) concentrations and TxCAD in a cohort of cardiac transplant recipients. METHODS: Forty-eight patients more than 5 yr after transplant were recruited from a cohort of 72 consecutive patients with in-depth analysis of homocysteine levels from the Cardiac Transplant Clinic. Early morning fasting blood was obtained, and the plasma separated and frozen within 30 min. Hcy concentrations were determined by high-performance liquid chromatography (HPLC) with pulsed integrated amperometry. Coronary angiograms were reviewed in a blinded fashion. TxCAD was diagnosed, using the most recent angiogram, when a >25% lesion was present anywhere in the coronary tree. RESULTS: Forty-eight patients transplanted between 1985 and 1994 were studied. The mean Hcy concentration for the cohort was 23.5+/-5.0 micromol/L, all patients had homocysteine levels above the upper range of normal (5-15 micromol/L). Hcy concentrations were significantly higher in patients with angiographic evidence of TxCAD: 25.0+/-5.9 vs. 21.9+/-3.4 micromol/L, p=0.03. This effect persisted when covariates were taken into account using logistic regression analysis. CONCLUSIONS: Hhcy is associated with TxCAD. Prospective studies are required to confirm this association and to assess the efficacy of Hcy-lowering therapy in this patient population.