Downregulation of neuronal cdk5/p35 in opioid addicts and opiate-treated rats: relation to neurofilament phosphorylation.

Neuronal cyclin-dependent kinase-5 (Cdk5) and its neuron-specific activator p35 play a major role in regulating the cytoskeleton dynamics. Since opioid addiction was associated with hyperphosphorylation of neurofilament (NF) in postmortem human brains, this study was undertaken to assess the status of the cdk5/p35 complex and its relation with NF-H phosphorylation in brains of chronic opioid abusers. Decreased immunodensities of cdk5 (18%) and p35 (26-44%) were found in the prefrontal cortex of opioid addicts compared with matched controls. In the same brains, the densities of p25 (a truncated neurotoxic form of p35), phosphatase PP2Ac and mu-calpain were found unaltered. Acute treatment of rats with morphine (30 mg/kg, 2 h) increased the density of cdk5 (35%), but not that of p35, in the cerebral cortex. In contrast, chronic morphine (10-100 mg/kg for 5 days) induced marked decreases in cdk5 (40%) and p35 (47%) in rat brain. In brains of opioid addicts, the density of phosphorylated NF-H was increased (43%) as well as the ratio of phosphorylated to nonphosphorylated NF-H forms (two-fold). In these brains, phosphorylated NF-H significantly correlated with p35 (r=0.58) but not with cdk5 (r=0.03). The results suggest that opiate addiction is associated with downregulation of cdk5/p35 levels in the brain. This downregulation and the aberrant hyperphosphorylation of NF-H proteins might have important consequences in the development of neural plasticity associated with opiate addiction in humans.     

Synergistic cytotoxicity and pharmacogenetics of gemcitabine and pemetrexed combination in pancreatic cancer cell lines.

PURPOSE: Gemcitabine is an inhibitor of ribonucleotide reductase (RR) and DNA synthesis and is an effective agent in the treatment of pancreas cancer. The present study investigates whether the multitargeted antifolate pemetrexed would be synergistic with gemcitabine against MIA PaCa-2, PANC-1, and Capan-1 pancreatic cancer cell lines. EXPERIMENTAL DESIGN: Cells were treated with gemcitabine and pemetrexed, and the type of drug interaction was assessed using the combination index. Cytotoxicity of gemcitabine was examined with inhibitors of (a) deoxycytidine kinase (dCK), which activates gemcitabine by phosphorylation, and (b) 5'-nucleotidase (drug dephosphorylation) and cytidine deaminase (drug deamination), the main inactivating enzymes. The effects of gemcitabine and pemetrexed on cell cycle were analyzed by flow cytometry, and apoptosis was examined by fluorescence microscopy. Finally, quantitative, real-time PCR was used to study the pharmacogenetics of the drug combination. RESULTS: Synergistic cytotoxicity and enhancement of apoptosis was demonstrated, mostly with the sequence pemetrexed-->gemcitabine. Pemetrexed increased cells in S phase, the most sensitive to gemcitabine, and a positive correlation was found between the expression ratio of dCK:RR and gemcitabine sensitivity. Indeed, pemetrexed significantly enhanced dCK gene expression (+227.9, +86.0, and +135.5% in MIA PaCa-2, PANC-1, and Capan-1 cells, respectively), and the crucial role of this enzyme was confirmed by impairment of gemcitabine cytotoxicity after dCK saturation with 2'-deoxycytidine. CONCLUSIONS: These data demonstrate that the gemcitabine and pemetrexed combination displays schedule-dependent synergistic cytotoxic activity, favorably modulates cell cycle, induces apoptosis, and enhances dCK expression in pancreatic cancer cells.     

Helicobacter pylori VacA toxin up-regulates vascular endothelial growth factor expression in MKN 28 gastric cells through an epidermal growth factor receptor-, cyclooxygenase-2-dependent mechanism.

PURPOSE: Helicobacter pylori causes gastric damage and is involved in gastric carcinogenesis. Vascular endothelial growth factor (VEGF) plays a major role in gastric mucosa repair and is overexpressed in gastric cancer. We investigated: (a) whether H. pylori, and in particular H. pylori VacA toxin, affected VEGF expression in gastric epithelial cells in culture; and (b) the signal transduction pathway involved in any effect exerted by H. pylori. EXPERIMENTAL DESIGN: MKN-28 cells were incubated with uninoculated BCF (control) or with BCF obtained from VacA-producing wild-type H. pylori 60190 strain or from its isogenic mutant 60190:v1, specifically lacking vacA gene in the presence or absence of ZD 1839, a selective inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, PD098059, a selective inhibitor of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase, the kinase responsible for ERK phosphorylation, or SC-236, a selective inhibitor of cyclooxygenase (COX)-2 for 24-48 h. RESULTS: (a) Toxigenic H. pylori up-regulated VEGF mRNA and protein expression and caused a 2.5-fold increase in VEGF release compared with control, whereas nontoxigenic H. pylori did not; (b) H. pylori VacA toxin-induced up-regulation of VEGF was counteracted by selective inhibition of EGFR tyrosine kinase; (c) toxigenic H. pylori activated the ERK/MAP kinase cascade, and inhibition of MAP kinase activation counteracted H. pylori-induced VEGF up-regulation; (d) toxigenic H. pylori up-regulated COX-2 expression, and this effect was counteracted by blockade of EGFR tyrosine kinase; and (e) COX-2 selective inhibition counteracted H. pylori-induced up-regulation of VEGF. CONCLUSION: (a) H. pylori up-regulates VEGF expression in gastric epithelial cells; and (b) this effect is specifically related to VacA toxin and seems to depend on the activation of an EGFR-, MAP kinase-, and COX-2-mediated pathway.     

Aminopenicillin allergy

Eight two children with histories of maculopapular or urticarial rashes during aminopenicillin treatment underwent skin tests, patch tests, radioallergosorbent assays and, in some cases, oral challenges. Hypersensitivity was diagnosed in eight (9.8%): immediate in four with urticarial reactions and delayed (that is cell mediated) in four with maculopapular rashes. In 49 children (38 with maculopapular eruptions, 11 with urticarial/angiooedematous reactions), negative allergologic findings were confirmed using oral challenges with the suspected drug. Maculopapular rashes may reflect delayed hypersensitivity to aminopenicillins, which can be diagnosed on the basis of late intradermal reactions and/or patch test positivity. The allergen panel must include the suspected aminopenicillin itself, as many cases are side chain specific. Most patients with urticarial reactions (more typical of immediate hypersensitivity) will also react to penicilloyl polylysine and minor determinant mixture. The time elapsed between the reaction and testing must be considered if negative results emerge, because IgE mediated sensitivity (unlike cell mediated forms) declines in the absence of antigen exposure.     

Spontaneous Splenic Rupture in a Patient with Acute Lymphoblastic Leukemia of Burkitt Type

We describe a case of spontaneous splenic rupture occurred in a patient with acute lymphoblastic leukemia of Burkitt type before starting cytotoxic chemotherapy. Left hypochondrial pain radiating to the homolateral shoulder was the only clinical symptom. Emergency computed tomography showed splenic laceration and hemoperitoneum. The patient underwent immediate laparotomy with splenectomy and experienced an uneventful postoperative recovery. Eight days after surgery, chemotherapy could be administered and complete remission was achieved. Although spontaneous rupture of the spleen is rare in leukemia and related disorders, this diagnosis should be taken in account also when clinical symptoms are mild. Following immediate operative management, patients may completely recover and receive cytotoxic chemotherapy with substantial possibilities of achieving complete remission.     

The use of the biofragmentable ring (BAR-Valtrac) in colon surgery

BACKGROUND: Clinical results of colic anastomosis using biofragmentable anastomosis ring (BAR-Valtrac) are presented. Such a method showed to be a real alternative technique to the usual ones. METHODS: Eighty-six colic anastomosis using BAR are collected, 76 of which performed as elective surgery and 10 in emergency. The patients were 47 males and 39 females, with a mean age of 64 years. In 63 cases the patients were affected by colic neoplastic disease, in 16 by complicated diverticular disease (stenosis or perforation) and 7 patients had neoplastic disease of other organs involving the colon BAR device was used in 48 colic reconstructions after segmentary resection and in 38 colic reconstructions after left hemicolectomy. In each case 31-34 mm BAR were used. RESULTS: No perioperative death occurred in our series. Only one case (2%) of anastomotic leak was observed, while in 3 cases (4%) intestinal canalization disorders occurred. No problems for ring expulsion occurred in any patient. Three late complications were observed, as three cases of asymptomatic substenosis discovered during instrumental follow-up and spontaneously cleared up. CONCLUSIONS: On the basis of clinical results, and according to those reported in literature BAR anastomosis is considered a safe, feasible and easy technique to perform colic anastomosis, even in emergency, limited to the intraperitoneal tract of the colon.     

Sequential endo-laparoscopic treatment in patients with common bile calculi

BACKGROUND: Laparoscopic treatment of common bile duct (CBD) stones is gaining great acceptance worldwide, but actually it requires skills and technologies too expensive for a great part of general surgeons. So endoscopic removal of CBD stones before cholecystectomy is usually performed. Since 1991 in our department we started a policy of selective preoperative cholangiopancreatography (ERCP) in patients suspected for choledocholithiasis and waiting for laparoscopic cholecystectomy. METHODS: A retrospective study has been made on a population of 1100 patients who underwent elective laparoscopic cholecystectomy in the period between January 1991 and December 1997. They were 391 male and 719 female with a mean age of 52 years, 126 of whom (11.5%) were selected to have ERCP preoperatively because they had clinical, biochemical and ultrasound signs of the presence of common bile duct stones (CBDS). RESULTS: Successful cannulation of the CBD was achieved in 124 cases (98.4%), with failures due to ampullary diverticula. In 7 cases (5.5%) a precut was necessary to obtain cannulation. Sphincterotomy was performed in 113 patients (89.7%). In 93 patients (73.8%) stones were found (87 macrolithiasis and 6 microlithiasis); in 91 (97.8%) stones were removed in one (87) or two (4) endoscopic session. There were 2 major complications (one bleeding and one severe pancreatitis) due to ERCP or a sphincterotomy. Two patients developed symptoms from unsuspected common bile duct stones after LC and were removed endoscopically. No complications during LC were due to ERCP or ES. CONCLUSIONS: Selective preoperative ERCP is an effective way of clearing the CBD stones before laparoscopic cholecystectomy, with low rate of complications related to endoscopic and laparoscopic procedures, and short mean hospital stay (5.5 days), according to the concept of minimally invasive treatment.     

Use of Street Methadone in Italian Heroin Addicts Presenting for Opioid Agonist Treatment

ABSTRACT

It is commonly assumed that people who are addicted to certain substances would abuse any substance. This position has never been supported by validly collected and analyzed research data. In this study, the authors examine the use of street methadone by heroin addicts seeking their first agonist opioid treatment in a clinical setting. Fifty-four heroin addicts who resorted to street methadone use were compared by socio-demographic, current clinical, and disease-related variables to 251 peers who do not use street methadone. Heroin addicts who resort to street methadone use are more likely to be females and to have a higher degree of education, are less likely to engage in polyabuse (use of more than three substances), are less severely ill, have been addicted for a shorter period of time, and have been seeking treatment sooner in the course of their disease. Also, they suffer from a wider range of psychopathological distress symptoms. In Italy, resorting to street methadone does not seem to be a surrogate form of heroin addiction, but rather represents means of harm reduction, with treatment seeking occurring shortly after its initiation. This should be accounted for when deciding on take-home policies and issues of potential methadone diversion.