Exposure to nicotine enhances acquisition of ethanol drinking by laboratory rats in a limited access paradigm

 Observations in humans suggest that the initial use of tobacco occurs in close temporal proximity to experimentation with alcohol. There have been relatively few research reports, however, examining possible interactions between these two agents. The present experiments examined the effect of nicotine exposure on the acquisition of ethanol drinking behavior in a limited access procedure. In experiment 1, rats were presented with 1-h access to ethanol solutions of increasing concentration for a period of 20 days. Subcutaneous injections of nicotine (0.6 or 1.2 mg/kg salt) or vehicle were administered 30 min prior to each ethanol presentation. Experiment 2 used a similar method, but rats were presented with water along with ethanol during the 1-h test session. Mecamylamine, a nicotinic receptor antagonist, was administered 30 min prior to the nicotine treatment. Nicotine was seen to produce a dose-dependent increase in ethanol drinking behavior which commenced at the 5% ethanol concentration and continued at 8% and again at 10%. In the second experiment, mecamylamine was observed to block completely the nicotine-induced increase in ethanol drinking behavior. The findings suggest that exposure to nicotine can facilitate the acquisition of ethanol drinking behavior in naive rats and that this effect is mediated by nicotine’s interaction at the nicotinic-cholinergic receptor. Received: 11 June 1998 / Final version: 1 October 1998     

Attenuation of voluntary ethanol consumption by dopamine-beta-hydroxylase inhibition (FLA-57): mediated by changes in aversion, reinforcement or both

The dopamine-beta-hydroxylase inhibitor, FLA-57, was reported by several investigators to reduce voluntary ethanol consumption in rats. The nature of the effect of FLA-57 on this behavior had been attributed to its involvement in both the mediation of positive reinforcing and aversive processes. In the present study, the capacity of FLA-57 to induce a conditioned taste aversion (CTA) in both a forward and a "nominally backward conditioning" paradigms was investigated. This was done in an attempt to assess the possible contribution of a FLA-57-induced CTA to the previously observed reduction in ethanol intake in several drinking studies. Furthermore, the ability of FLA-57 to induce a CTA in a nonnovel situation, where the taste of the presented solution (ethanol or saccharin) was familiar to the animals, was also assessed. The inclusion of these specific conditions was necessitated by the attempt to create conditions similar to those prevalent in drinking studies. We found that FLA-57, in both conditioning paradigms, induced a significant CTA. Animals, naive and experienced with the taste of ethanol or saccharin, exhibited a CTA following the administration of FLA-57. However, the magnitude and rate of extinction of the observed CTAs did not resemble those observed in studies on the effects of FLA-57 on ethanol intake. The results of this study suggest that while it is possible that FLA-57 exerts its effect on ethanol intake, at least in part, through an aversive mechanism, such a mechanism is unlikely to be the exclusive process through which ethanol ingestion is attenuated.     

Biomechanical studies of a dynamized anterior thoracolumbar implant

STUDY DESIGN: An in vitro investigation into the biomechanical properties of a dynamized anterolateral compression implant that allows controlled subsidence. OBJECTIVES: To determine the extent to which both modes of the anterolateral compression implant (controlled collapsing and rigid) are able to reestablish the stability of the lumbar spine after L4 corpectomy. SUMMARY OF BACKGROUND DATA: Over time, anterior and posterior spinal implants have been associated with progressive angulation, and occasionally implant failure and breakage. To circumvent this occurrence and provide better graft loading, dynamized or collapsing devices for clinical use have been developed. METHODS: Eight fresh calf spines (L1-L6) were placed in a biomechanical testing frame. Pure moments of 6 Nm were loaded onto the intact spine in six directions: flexion, extension, right and left lateral bending, and right and left axial rotation. A total L4 corpectomy then was performed, and the defect grafted with a wooden dowel. Loading was repeated after the specimens were stabilized using the two modes of the anterolateral compression implant in succession. RESULTS: The results showed that both modes of the implant (the rigid mode in particular) restore the stiffness of the unstable spine to normal levels of flexion, extension, and right and left lateral bending, even to levels exceeding normal. These devices, however, fall short of achieving normal stability in right and left axial rotation. CONCLUSION: In the cadaveric calf spine after L4 corpectomy, restoration of stability with a dynamized anterior spinal implant is possible in flexion, extension, and right and left lateral bending, but not in axial rotation.     

Cerebellar astrocytoma in an adult with extensive leptomeningeal spread

A rare case of a benign cerebellar astrocytoma in an adult is reported. This tumour had an extensive leptomeningeal spread in the cerebellar convexity, basal cisterns and spinal cord. The most unusual and radiologically demonstrated extension was also into the sella and Meckel's cave. The case is discussed and the literature is briefly reviewed.     

Unusual massive neurinoma in the suboccipital region--case report

An 8-year-old boy with no evidence of von Recklinghausen's disease presented with an unusual neurinoma manifesting as a gradually progressive swelling in the suboccipital region over 2 years. The lesion was massive and had widely eroded the posterior aspects of the atlas, axis, and suboccipital bone. The tumor had involved the dura of the sigmoid and transverse sinuses, was highly vascular, and had encased the ipsilateral vertebral artery. The tumor was almost completely resected although with considerable loss of blood through a large rent in the right sigmoid sinus. This unusual benign neurinoma most probably arose from the second cervical ganglion.     

A comparison of self-reported colorectal cancer screening with medical records.

The purpose of this study was to compare self-reports of colorectal cancer (CRC) screening by fecal occult blood test (FOBT), sigmoidoscopy, and colonoscopy with medical records in a multiprovider health care setting. Relatives of CRC patients residing in Ontario, Canada completed a questionnaire indicating whether or not they had ever had any CRC screening tests. Medical records from physician's offices and hospitals were compared with the self reports, and where possible, reasons were obtained for nonmatching reports. Medical records for colonoscopies were readily available from various sources, and self-reports of this procedure were very accurate (kappa statistic for agreement beyond chance = 0.87). For sigmoidoscopy and FOBT, the agreement was poorer (kappa = 0.29 and 0.32, respectively); however, there were difficulties in obtaining records for these two procedures. Sigmoidoscopy procedures that took place many years ago were difficult to document, and physician's offices were unable to provide FOBT reports in many cases. Self-reports of colonoscopy were very accurate in this population, whereas self-reports of sigmoidoscopy and FOBT are somewhat less accurate, although this is likely due to challenges in obtaining a confirmatory record rather than an overreporting of tests. In a multiprovider publicly insured health care setting such as Canada, using self-reported information is likely to provide sufficiently accurate information for colonoscopy, but for other CRC screening tests, there may be difficulty in obtaining true estimates of the frequencies of these procedures.     

Metastatic spinal cord compression: radiotherapy outcome and dose fractionation.

BACKGROUND AND PURPOSE: No standard dose fractionation has been defined for metastatic spinal cord compression. This retrospective analysis was undertaken to explore the impact of hypofractionated treatment compared to conventional multifraction treatment. MATERIALS AND METHODS: One hundred and two consecutive patients referred to Mount Vernon Cancer Centre with metastatic spinal canal compression confirmed on MR scan in 95% with median age 68 years (range 32-90) and main primary tumour types breast (28%), prostate (28%) and lung (20%); 51% of patients were fully ambulant at diagnosis, 41% ambulant but with paraparesis and 9% had complete paraplegia. Spinal radiotherapy was given delivering a single dose in 32% and 20 Gy in five fractions in 64%. RESULTS: The median survival was 3.5 months; survival was significantly related to primary site and motor function at presentation. Normal ambulation was achieved in 58% at 2 weeks and 71% up to 2 months after treatment. No patient who presented with paraplegia regained function. At presentation 59% of patients had severe pain, which fell to 8% at 2 weeks. Comparing those patients who received one or two dose treatments with those who received protracted fractionation, the two groups were matched for age, sex, primary site and site of compression. Relatively more patients treated with one or two doses had paraplegia; 19% vs. 3%. Despite this outcome in the two groups was equivalent for motor and sphincter function and pain control. CONCLUSIONS: Metastatic spinal canal compression carries a poor prognosis. Urgent treatment will maintain and improve motor function in patients presenting ambulant but those who have paraplegia at presentation do not improve and have a very short survival. In this series no difference in outcome was seen between patients treated with one or two radiation doses compared to multifraction treatment; a randomised trial comparing fractionation schedules would be justified.     

The statins as anticancer agents.

3-Hydroxy-3-methylgutaryl CoA reductase inhibitors, commonly referred to as the statins, have proven therapeutic and preventative effects in cardiovascular diseases. Recently, there are emerging interests in their use as anticancer agents based on preclinical evidence of their antiproliferative, proapoptotic, anti-invasive, and radiosensitizing properties. Inhibition of 3-hydroxy-3-methylgutaryl CoA reductase by the statins interferes with the rate-limiting step of the mevalonate pathway, leading to reduced levels of mevalonate and its downstream products, many of which play important roles in critical cellular functions such as membrane integrity, cell signaling, protein synthesis, and cell cycle progression. Perturbations of these processes in neoplastic cells by the statins may therefore result in control of tumor initiation, growth, and metastasis. The statins have demonstrated growth inhibitory activity in cancer cell lines and preclinical tumor models in animals. Phase I trials of statins in humans have demonstrated myotoxicity as their main dose-limiting toxicity, and Phase II trials in various tumor types are ongoing to evaluate their efficacy. Potential future directions in the development of the statins as anticancer agents include combinations with chemotherapeutic or other molecular-targeted agents, combinations with radiotherapy, maintenance therapy in minimal disease status, and as chemopreventive therapy.     

Open thumb forceps. An unusual foreign body in the urethra: technique of its removal

A great variety of foreign bodies in the urethra have been reported in the literature. Mostly, these cases were reported to emphasize the unusual nature of the objects requiring technical modifications for their removal. We report an interesting case of self introduced open thumb forceps into the urethra and technique of its retrieval.