RNA interference validation of detoxification genes involved in ivermectin tolerance in Drosophila melanogaster.

Previously, we observed increased transcription levels of specific cytochrome P450 monooxygenase (P450) and adenosine triphosphate binding cassette (ABC) transporter genes in human body lice, Pediculus humanus humanus, following exposure to ivermectin using the non-invasive induction assay, which resulted in tolerance. To confirm the roles of these genes in induction and tolerance, the robust genetic model insect Drosophila melanogaster was chosen. Orthologous genes corresponding to the body louse P450 (Cyp9f2, Cyp6g2 and Cyp9h1) and ABC transporter (Mrp1, GC1824 as an ABCB type and CG3327 as an ABCG type) genes were selected for in vivo bioassay. Following a brief treatment with a sublethal dose of ivermectin, the mortality response was significantly slower, indicating the presence of tolerance. Concurrently, the transcription levels of Cyp9f2 and Mrp1 at 3 h and those of Cyp6g2, Cyp9h1, Mrp1, CG1824 and CG3327 at 6 h post-treatment were upregulated, indicating gene induction. In behavioural bioassay using GAL4/UAS-RNA interference transgenic fly lines, increased susceptibility to ivermectin was observed following heat shock in the Cyp9f2 , Cyp6g2 , Cyp9h1 , Mrp1 or CG3327-knockdown flies. Considering that these five genes are orthologous to those which had the largest over-expression level following ivermectin-induced tolerance in the body louse, the current results suggest that they are also associated with ivermectin detoxification in D. melanogaster and that body lice and D. melanogaster are likely to share, in part, similar mechanisms of tolerance to ivermectin.

Intraduodenal free fatty acids rather than triglycerides are responsible for the release of CCK in humans.

Exocrine pancreas from different species behaves differently in response to the presence of intact or digested nutrients in the duodenum. A failure of cholecystokinin (CCK) release after a meal has been shown among patients with exocrine pancreatic insufficiency. This abnormality could be restored by the administration of pancreatic extracts, suggesting that digested rather than intact nutrients are responsible for the release of CCK and subsequently gallbladder contraction in humans. The aim of this study was to determine the specific role of different lipidic stimuli in humans. Seven male patients (mean age, 52 years) with pancreatic insufficiency secondary to chronic pancreatitis were selected. Pancreatic insufficiency was considered severe in five of them (lipase output, < 1,000 IU/min) and moderate in another two (lipase output, > 1,000 and < 2,300 IU/min). Plasma CCK (by bioassay), gallbladder contraction (by ultrasound), and enzyme output (chymotrypsin) in response to duodenal administration of either oleic acid as free fatty acids or 20% Intralipid as triglycerides were measured in each patient with at least a 48-h interval between each test. In all these patients with pancreatic insufficiency, duodenal perfusion of free fatty acids generated a more pronounced (91 +/- 11 vs. 49 +/- 21 pM) and faster (15 vs. 30 min) (p < 0.05) CCK release than triglycerides. Furthermore, gallbladder contraction was more efficient when free fatty acids instead of triglycerides were administered in the duodenum (86 +/- 5 vs. 69 +/- 4%) at 10 min (p < 0.05) and (73 +/- 8 vs. 51 +/- 5%) at 15 min (p < 0.03). Among patients with measurable residual pancreatic function, enzyme outputs were shown to be higher during free fatty acid than triglyceride perfusion. In humans, free fatty acids rather than triglycerides, when present in the duodenum, stimulate CCK release and gallbladder contraction. In patients with moderate pancreatic insufficiency this phenomenon may increase residual enzymatic secretion. These results allow us to encourage the development of enzymatic preparations as acid-resistant lipases that cause a fast release of free fatty acids in the duodenum.

[Efficacy and tolerance of praziquantel (Biltricide) in the treatment of distomatosis caused by Fasciola hepatica]. / Efficacité et tolérance du praziquantel (Biltricide) dans le traitement de la distomatose à Fasciola hepatica.

OBJECTIVES: Due to the side-effects of dehydroemetine, we have chosen praziquantel, a broad-spectrum antihelmintic, as a treatment for distomatosis secondary to Fasciola hepatica in humans. The aim of this retrospective study was to evaluate the efficacy and tolerance to praziquantel in patients with this disease. METHODS: Twenty-five patients (12 men) with a definite diagnosis of distomatosis and no previous treatment were followed-up between 8 months and 3 years (> 18 months in 76% of cases). The follow-up was based on clinical, biochemical and serological criteria. All patients received praziquantel (75 mg/kg/day orally) for 5 days. Treatment was started after endoscopic or surgical removal of parasites locolized in the biliary tract, in two patients. A similar therapeutic course was administered twice in four patients with persistent clinical symptoms, hypereosinophilia or arch 2 on immunoelectrophoresis. RESULTS: Cumulative rates of patients with normalized eosinophilia and seronegativation at 6, 9 and 12 months were 55, 65, 75% and 55, 70, 100%, respectively. Complete recovery occurred in 18 patients (72%) whereas hypereosinophilia persisted for more than one year in 5 patients. No side-effects, except transient nausea in a few cases, were observed. CONCLUSION: Since praziquantel seems to be both effective and well tolerated in a large proportion of patients, this drug can be recommended as a first choice for distomatosis due to Fasciola hepatica in human.

Gallstone pancreatitis and the effect of cholecystectomy: a population-based cohort study.

Although an association between gallstones and pancreatitis has been recognized for almost 100 years, the risk of acute pancreatitis in patients with gallstones and the effect of cholecystectomy on this risk have been unknown. The complete medical records of the 2,583 residents of Rochester, Minnesota, who had gallstones diagnosed between 1950 and 1970 were carefully reviewed to detect the development of acute pancreatitis. Acute pancreatitis developed in only 89 subjects (3.4% of the cohort); however, the relative risk for acute pancreatitis (before cholecystectomy) was increased 14 to 35 times in men and 12 to 25 times in women. The overall age- and sex-adjusted incidence of acute pancreatitis of the members of the cohort before cholecystectomy was 6.3 to 14.8 per 1,000 person-years of follow-up. Cholecystectomy in 1,560 patients without a prior attack of pancreatitis reduced the relative risk to 1.9 and 2.0 for men and women respectively. Of 58 patients who had a cholecystectomy after an attack of acute pancreatitis and underwent follow-up for a median of 15 years postoperatively, only 2 had another attack of acute pancreatitis, and the cause of the pancreatitis was unrelated to gallstones in both. In summary, patients with gallstones have a considerably increased relative risk for acute pancreatitis and, regardless of whether prior attacks of pancreatitis have occurred, cholecystectomy reduces this risk to almost the same level as in the general population. Because the overall incidence of pancreatitis is low, however, performance of cholecystectomy to prevent pancreatitis is indicated only if an attack of acute pancreatitis has already occurred.

Gallstones, gallbladder cancer, and other gastrointestinal malignancies. An epidemiologic study in Rochester, Minnesota.

All 2583 residents of Rochester, Minnesota, who had gallstones initially diagnosed during the years 1950 to 1970 were followed for the development of gastrointestinal malignancies. Although 69 members of the cohort subsequently developed 72 gastrointestinal malignancies, this number of cases did not exceed the 76 cases expected (relative risk, 1.0). The risk for gallbladder cancer was increased threefold, but the increase was significant only in men (p = 0.05; 95% confidence interval, 1.0 to 30.0). The absolute incidence and the total number of men and women who developed gallbladder cancer was low (n = 5). The actual incidence of other gastrointestinal malignancies in our cohort with gallstones did not exceed the expected incidence in the general population of Rochester, Minnesota. Specifically, the risk for colon cancer was not increased, even after cholecystectomy. These data support an association between cholelithiasis and gallbladder cancer. We found, however, no association between cholelithiasis or cholecystectomy and any other gastrointestinal malignancy.