Lack of correlation between predicted and actual off-target effects of short-interfering RNAs targeting the human papillomavirus type 16 E7 oncogene.

BACKGROUND: When designing therapeutic short-interfering RNAs (siRNAs), off-target effects (OTEs) are usually predicted by computational quantification of messenger RNAs (mRNAs) that contain matches to the siRNA seed sequence in their 3' UTRs. It is assumed that the higher the number of predicted transcriptional OTEs, the greater the size of the actual OTE signature and the more detrimental the phenotypic consequences in target-negative cells. METHODS: We tested this general assumption by investigating the OTEs of potential therapeutic siRNAs targeting the human papillomavirus (HPV) type-16 E7 oncogene. We studied HPV-negative squamous epithelial cells, from normal cervix (NCx) and skin (HaCaT), which would be vulnerable to 'bystander' OTEs following transfection in vivo. RESULTS: We observed no correlation between the number of computationally predicted OTEs and the actual number of seed-dependent OTEs (P=0.76). On average only 20.5% of actual transcriptional OTEs were seed-dependent (i.e., predicted). The unpredicted OTEs included stimulation of innate immune pathways, as well as indirect (downstream) effects of other OTEs, which affected important cancer-associated pathways. Although most significant OTEs observed were seen in both NCx and HaCaT cells, only 0-5.9% of differentially expressed genes overlapped between the two cell types. CONCLUSION: These data do not support the assumption that actual OTEs correlate well with predicted OTEs.

Sphincter preservation for low rectal carcinoma--the Durban experience.

With the increasing interest in sphincter preservation in the treatment of low rectal carcinoma, we retrospectively reviewed the present surgical options--sphincter preservation with colo-anal anastomosis, and the radical abdominoperineal resection (APR). Seventeen patients had sphincter preservation with colo-anal anastomosis and 12 an APR; 53% of the sphincter preservation group survived, compared with 25% of those patients who had APR. We conclude that in selected cases sphincter preservation would not compromise the chance of cure and would save the patient from a permanent colostomy.

Thyroid carcinosarcoma. A case report.

A thyroid carcinosarcoma--a rare neoplasm of the thyroid gland--in an elderly woman is described. On histological examination the tumour showed the characteristic biphasic pattern of follicular carcinoma and mesenchymal differentiation with a chondrosarcomatous component and osseous metaplasia. The clinical features and details of the histopathological and immunohistological examinations of this tumour are reported.

Acute pernicious beriberi in a patient receiving parenteral nutrition. A case report.

Parenteral nutrition is being used increasingly in the treatment of the critically ill patient but it causes complications and metabolic derangement. A patient receiving parenteral nutrition in whom protracted vomiting from intestinal obstruction led to the development of acute cardiovascular beriberi (Shoshin) with severe metabolic acidosis--probably lactic--is described. The acidosis was refractory to bicarbonate infusion and inotropic support but the administration of intravenous thiamine 100 mg resulted in a dramatic recovery. Biochemical confirmation of thiamine deficiency was obtained by the measurement of an elevated thiamine pyrophosphate level (24.4%). The patient received thiamine 2.4 mg weekly, a dose that proved insufficient. Thiamine deficiency should be considered when patients receiving parenteral nutrition develop metabolic acidosis with a wide anion gap, even if vitamin supplementation appears adequate.

Bronchobiliary fistula after chronic pancreatitis. A case report.

A case of cholangitis secondary to chronic pancreatitis is reported. A liver abscess ruptured into the chest and the patient presented coughing bile. Symptoms were cured by a choledochojejunostomy, providing drainage for the obstructed common bile duct. To our knowledge this is the first reported case of a bronchobiliary fistula developing as a result of chronic pancreatitis. The principles of treatment are discussed.

Permanent-access hepaticojejunostomy.

A new technique of hepaticojejunostomy is described. The technique involves the incorporation of a cutaneous access stoma in the Roux-en-Y loop of jejunum used for the anastomosis. This stoma provides permanent access to the biliary-intestinal anastomosis and to the hepatobiliary tree for non-operative management of chronic and recurrent biliary tract problems.

Rectal administration of metronidazole in severely ill patients.

Ten severely ill patients with life threatening sepsis received metronidazole as suppositories and blood concentrations of the drug were measured twice daily over five days. Therapeutic blood concentrations of metronidazole were maintained at all times in all patients. Rectal administration of metronidazole is accepted as effective prophylaxis against infection associated with surgery and as treatment of established infection. This study shows that in gravely ill patients metronidazole administered as suppositories gives perfectly adequate therapeutic serum concentrations of the drug, but that to achieve these concentrations rapidly the first suppository should be given with an intravenous loading dose.