Experimental Research Showing the Reduction of Naloxone-Place Aversion by Oral Zinc Administration in Rats.

Previous studies showed the attenuation of both morphine-dependence and morphine-place preference by zinc. Conditioned place preference and aversion are experimental models frequently used to test the reward-stimulating, respectively the aversive effects induced by different stimuli or substances. Addictive substances usually induce place preference (exhibit reward-stimulating properties), while their antagonists determine place-avoidance (aversion). The present study aimed to assess the effect determined by zinc sulphate oral administration (2 and 4 mg/kg/day, 14 days, prior to habituation) on the place aversion induced by two naloxone doses (1.5 and 2.5 mg/kg/administration). The results show a robust, dose-dependent reduction of the aversion determined by both naloxone doses (the aversion induced by 1.5 mg/kg naloxone was reduced with 15%-the lower zinc dose and with 24%-the higher zinc dose; the aversion induced by 2.5 mg/kg naloxone was reduced with 16%-the lower zinc dose and with 29%-the higher zinc dose). This represents a new proof of the interactions between zinc and opioidergic system and a further argument for dietary zinc supplementation in patients on opioids for cancer-related chronic pain.

Multidisciplinary approach and anesthetic management of a surgical cancer patient with methylene tetrahydrofolate reductase deficiency: a case report and review of the literature.

INTRODUCTION: Hyperhomocysteinemia is a known risk factor for myocardial infarction, stroke, peripheral vascular disease, and thrombosis. Elevated plasma homocysteine levels have been demonstrated in patients with recurrent episodes or a single episode of thrombosis. Here we describe the development of cardiovascular disease as a complication of a surgical intervention in a patient with colorectal cancer and hyperhomocysteinemia. CASE PRESENTATION: A 65-year-old Caucasian man complained of pain and constipation, attributed to previously diagnosed adenocarcinoma (stage IIB) of the hepatic flexure. An anamnestic investigation showed that he had undergone two surgical interventions. During both, he suffered thrombotic postoperative complications, a deep vein thrombosis of the upper extremity after the first operation and retinal vein occlusion after the second. He was diagnosed with hyperhomocysteinemia associated with a homozygous C677T mutation of the gene encoding the enzyme methylenetetrahydrofolate reductase. Our patient was initially treated with folic acid and high-dose B vitamins. On day 7 he underwent a right hemicolectomy. Anesthesia was performed with sevoflurane in 40% O2 and without the use of nitrous oxide. Postoperatively, our patient remained on folic acid and B vitamins and was without immediate or subsequent complications. CONCLUSIONS: Neoplastic disease and related surgery followed by the administration of chemotherapeutic drugs alter the hemostatic balance in cancer patients. Those suspected of also having a thrombophilic disease require a thorough laboratory diagnostic workup, including a molecular analysis aimed at identifying the genetic mutation responsible for the hyperhomocysteinemia, as indicated. The case described in this report highlights the importance of a multidisciplinary approach that includes expertise in peri-operative anesthesia, surgery, oncology, and hematology.

Plasma glutamine decreases immediately after surgery and is related to incisiveness.

Glutamine (gln) is the most abundant free amino acid in the blood. It is involved in important metabolic and biochemical processes, like cell proliferation and oxidative stress. Previous studies have demonstrated that gln concentration in human plasma decreases in several conditions such as sepsis, ischemia-reperfusion, trauma, major surgery and burn. The aim of the present work was to compare the acute effects of different types of surgical interventions and of anesthetization on blood gln concentration. Plasma samples from 88 subjects (30 males and 58 females) were collected before and after major or minor surgery and the gln concentration was analyzed with high-performance liquid chromatography. The results showed that plasma gln concentration after surgery was lower than pre-surgery values and that in major surgery the decrease of gln was higher than in minor surgery. No significant effect was shown for sex or type of anesthesia. These results demonstrate the importance of a gln supplementation before a surgical intervention and show that the amount of gln supplementation should also be adjusted based on the type of surgery.