beta-Arrestin2, interacting with phosphodiesterase 4, regulates synaptic release probability and presynaptic inhibition by opioids

Most mu-opioid receptor agonists recruit beta-arrestin2, with some exceptions such as morphine. Surprisingly, however, the acute analgesic effect of morphine is enhanced in the absence of beta-arrestin2. To resolve this paradox, we examined the effects of morphine and fentanyl in acute brain slices of the locus coeruleus and the periaqueductal gray from beta-arrestin2 knockout mice. We report that, in these mice, presynaptic inhibition of evoked inhibitory postsynaptic currents was enhanced, whereas postsynaptic G protein-coupled K(+) (Kir3/GIRK) currents were unaffected. The frequency, but not amplitude, of miniature inhibitory postsynaptic currents was increased in beta-arrestin2 knockout mice, indicating a higher release probability compared to WT mice. The increased release probability resulted from increased cAMP levels because of impaired phosphodiesterase 4 function and conferred an enhanced efficacy of morphine to inhibit GABA release. Thus, beta-arrestin2 attenuates presynaptic inhibition by opioids independent of mu-opioid receptor-driven recruitment, which may make beta-arrestin2 a promising target for regulating analgesia.     

Prevalence of C282Y and E168X HFE mutations in an Italian population of Northern European ancestry

BACKGROUND AND OBJECTIVES: In Italy, the prevalence of C282Y is lower than in Northern European countries. We hypothesized a higher prevalence of C282Y in Northern than in Southern Italian populations. We previously identified a nonsense mutation (E168X) in hemochromatosis probands originating from a region in the north-west of Italy. We aimed to define the prevalence of C282Y and E168X in that region and the origin of the E168X mutation by haplotype analysis. DESIGN AND METHODS: Six-hundred and six blood donors were investigated for C282Y, H63D, S65C and E168X mutations by polymerase chain reaction (PCR)-restriction assays. Three hundred were also tested for rare HFE and TFR2 mutations by reverse-hybridization test strips. D6S265, D6S105 and D6S1281 microsatellites were analyzed to define E168X 6p-associated haplotypes. RESULTS: One C282Y homozygote, thirteen C282Y/ H63D compound heterozygotes, four E168X heterozygotes and three E168X/H63D compound heterozygotes were found. The allele frequencies of C282Y, H63D, S65C, and E168X were 4.7%, 14.9%, 0.74% and 0.58%, respectively. INTERPRETATION AND CONCLUSIONS: The prevalence of C282Y in the region investigated was much higher than that previously reported in Italy. This finding is probably due to the heavy Celtic component of this north-western population and suggests that in populations of Northern Italian descent screening studies for hemochromatosis could be cost-effective. The prevalence of E168X in this region, although low, suggests that the mutation probably originated here many years ago and its frequency increased as a result of a local founder effect. Given its severity, we suggest that the E168X mutation should be searched for in all hemochromatosis patients of Northern ancestry with an incomplete HFE genotype.     

Non-episodic angioedema associated with eosinophilia following <Emphasis Type="Italic">Mycoplasma pneumoniae</Emphasis> infection

Episodic angioedema with eosinophilia is characterized by recurrent angioedema, peripheral eosinophilia, fever, weight gain, elevated serum immunoglobulin M (IgM), and a benign course lacking any internal organ involvement. A non-episodic variant has also been reported which is limited to a single attack and normally is less severe than the episodic type. We report a case of Mycoplasma pneumoniae infection with dermatological manifestation that was followed by non-episodic angioedema with eosinophilia including fever, weight gain, and elevated serum IgM. Even though the patient’s clinical characteristics resemble episodic angioedema with eosinophilia as reported by Gleich, angioedema was non-episodic. This may be due to systemic corticosteroid treatment which was prescribed because of persistent skin manifestation following M. pneumoniae infection. The current report is the first observation suggesting that angioedema associated with eosinophilia may be triggered by atypical bacterial infection.     

Trypsinogen Activation Peptides (TAP) in Peritoneal Fluid as Predictors of Late Histopathologic Injury in Necrotizing Pancreatitis of the Rat

The levels of trypsinogen activation peptides(TAP) were quantified by ELISA immunoassay in acutepancreatitis of the rat and compared to the degree oflate histopathological sequelae and exocrine functional impairment 4 and 12 weeks after the acute phaseof the disease. For this purpose acute pancreatitis ofdifferent severity was induced using a suitable ratmodel recently described. Forty five surviving animals were studied. The level of TAP inperitoneal exudate measured 3 and 6 hr afterpancreatitis induction correlated well with the amountof the late histopathological injury at the end of thecorresponding observation period (at 4 weeks after 3 hr: r =0.75, P = 0.003, after 6 hr: r = 0.72, P = 0.005,Pearson; and at 12 weeks after 3 hr: r = 0.86, P =0.0001, after 6 hr: r = 0.84, P = 0.0001, Pearson). A negative correlation of TAP with the impairmentof exocrine function was found only at 4 weeks for thesecretion of total protein (r = –0.76 after 3 hr;r = –0.62 after 6 hr) and for exocrine function (r = –0.67 after 3 hr, r = –0.57 after6 hr), but not at 12 weeks after acute pancreatitis. Nocorrelation with plasma amylase and lipase was found. Weconclude that quantitation of TAP in ascites provides an accurate prediction of late histopathologicsequelae. Pancreatic exocrine function could bepredicted by TAP assay only in the early stage afterpancreatitis induction (eg, four weeks). In later stages of the disease (eg, 12 weeks) remainingpancreatic tissue seems to compensate for any exocrinedeficits that have occurred.     

Passive smoking increases platelet thromboxane

Although active smoking is known to enhance platelet thromboxane production, no data on passive smoking are available yet. In an 18 m³ room, the influence of single and repeated exposure to passive smoke for 60 minutes was assessed in nonsmokers and smokers. Smokers and nonsmokers were matched for sex and age. All the evaluated parameters (plasma TXB₂, serum TXB₂, malondialdehyde, 11-dehydro-TXB₂, conversion of exogenous arachidonic acid to hydroxy-5,8,10-heptadecatrienoic acid, and TXB₂) were higher in smokers than nonsmokers at baseline conditions, immediately and 6 hours after passive exposure to cigarette smoke. Repeated exposure of nonsmokers rendered their platelets more activated, so they became closer to the behavior of smokers. Contributing to the development of hemostatic imbalance, these results indicate that passive smoking may enhance thromboxane A₂ release from the platelets.Presented at the 36^th Annual World Congress, International College of Angiology, New York, New York, July 1994     

18F‐Fluorodeoxyglucose (FDG)‐PET features of focal nodular hyperplasia (FNH) of the liver

Abstract: Aim: The aim of this paper is to describe the imaging pattern of focal nodular hyperplasia (FNH) by ¹⁸F‐fluorodeoxyglucose (18F‐FDG) positron emission tomography (PET). Methods: Eight consecutive asymptomatic patients with histologic proof of FNH underwent 18F‐FDG PET imaging. The lesions were found incidentally. The 18F‐FDG PET imaging was performed with a dedicated PET tomograph after intravenous injection of 300–370 MBq 18F‐FDG. The 18F‐FDG accumulation in the lesions was (semi)quantified by calculating the standardized uptake value (SUV) and SUV has been corrected for the lean body mass (LBM). Eight patients with liver metastases spread from melanoma (n=2) and colorectal carcinoma (n=6) served as controls. The size of the FNH lesions and of the control group ranged from 2.0 to 8.5 cm (mean 4.83 cm±2.37) and from 1.5 to 6 cm (mean 3.28±1.52), respectively. Results: While in malignant liver lesions the accumulation of 18F‐FDG was significantly increased, all FNH lesions showed normal or even decreased accumulation of 18F‐FDG. In FNH lesions, SUV ranged between 1.5 and 2.6 (mean 2.12±0.38), whereas all liver metastases showed an increased SUV ranging between 6.20 and 16.00 (mean 10.07±3.79). The SUV corrected for LMB (SUV_LBM) was similar to the SUV and ranged between 0.9 and 2.2 (mean 1.81±0.41) for FNH and between 5.9 and 16.3 (mean 9.15±4.03), respectively. Conclusion: In contrast to liver metastases, there is no increased glucose metabolism in FNH in vivo. The imaging feature of FNH by 18F‐FDG‐PET imaging is not specific for FNH; however, it may be helpful to differentiate FNH from liver metastases in cancer patients if radiological methods are not diagnostic.     

Treatment of hepatitis C virus in human immunodeficiency virus infected patients in "real life": modifications in two large surveys between 2004 and 2006

BACKGROUND/AIMS: To analyze the barriers to HCV treatment in HIV-HCV co-infected patients and their evolution between 2004 and 2006. METHODS: Three hundred and eighty HIV-HCV co-infected patients were prospectively included in surveys from November 22 to 29, 2004 (2004 survey), and 416 from April 3 to 10, 2006 (2006 survey). RESULTS: Patients in 2006 compared to those in 2004 had negative HCV RNA more often (24% vs. 12%). The rate of liver biopsy was similar (56% vs. 54%) while 24% had had a non-invasive liver damage assessment. The rate of previous treatment for HCV infection was higher (48% vs. 26%). The main reasons for HCV non-treatment have changed: HCV treatment deemed questionable (44% vs. 53%), lack of liver biopsy (18% vs. 33%), physicians' conviction of poor patient compliance (20% vs. 30%). In both surveys, HCV treated patients were more often of European origin, had better control of HIV infection, and had a liver damage assessment more often. CONCLUSIONS: The care of HIV-HCV co-infected patients has changed significantly in "real life". These results underline the importance of continuing efforts to educate physicians and patients in order to increase the access of co-infected patients to HCV treatment.     

Expiratory-Synchronized Sleep in a Quadriplegic Patient Using Inspiratory Neck Muscles To Breathe

In a patient with C3 quadriplegia causing complete diaphragm paralysis who developed inspiratory neck muscles (INM) hypertrophy to sustain ventilation, spontaneous breathing deeply altered sleep architecture, relegating sleep to the expiratory phase of the ventilatory cycle. A polysomnographic recording performed during mechanical ventilation (without INM activity), showed that sleep was abnormal but unaffected by the respiratory cycle. During spontaneous breathing, the polygraphic recordings showed expiratory microsleep episodes, with inspiratory arousals synchronous to bursts of INM activity. This case report illustrates the powerful adaptability of the respiratory and sleep control systems to maintain each vital function.