Carcinogenicity of dextran sulfate sodium in relation to its molecular weight

The carcinogenicity of dextran and 3 kinds of dextran sulfate sodium with different molecular weights and almost the same sulfur content were compared in ACI rats. Dextran sulfate sodium of molecular weight 54,000 showed a strong carcinogenic activity when it was given orally as 2.5% diet, whereas dextran sulfate sodium of molecular weight 520,000 and 9500 and dextran showed no significant carcinogenicity, i.e. the peak of carcinogenic activity of dextran sulfate sodium appeared at molecular weight 54,000, and dextran sulfates with larger or smaller molecular weights had no carcinogenic activity.     

Epilation of hair-bearing urethral grafts using the neodymium:YAG surgical laser

Nonhair-bearing skin should be used when grafting is necessary during urethroplasty for stricture or hypospadias repair. Occasionally, this is not possible or hair-bearing skin is used inadvertently. Traditionally, electrocoagulation has been the method used for epilation when intraluminal hair has become a problem, such as interfering with flow, as a focus for recurrent urinary tract infection or acting as a nidus for calculus formation. Electrocautery also is performed during grafting in an attempt to prevent the growth of hair when hair-bearing skin is used. Unfortunately, due to lack of penetration the hair follicles are not destroyed and the epilating procedure fails or is only partially successful. The neodymium:YAG surgical laser can photocoagulate tissue to a depth up to 5.0 mm, and thus, has the ability to destroy hair follicles. We report 4 cases presenting with clinical problems directly related to hair-bearing urethral grafts successfully treated by neodymium:YAG laser epilation.     

Esophageal pH monitoring for gastroesophageal reflux: a United Kingdom study

Esophageal pH monitoring is the accepted standard for the investigation of gastroesophageal reflux (GER) in adults. A postal questionnaire was sent to 912 United Kingdom paediatric physicians & surgeons. Five hundred forty-seven (61%) replied, with 124 (22.7%) currently using the technique, mostly in conjunction with barium swallow and/or esophagoscopy. The use of pH monitoring to quantify GER was also accepted in principal as being the best determinant of reflux by a further 186 (34%), but as yet was unavailable in their hospitals. Pediatricians were also questioned as to their management of children with GER. The majority were treated medically with a variety of antireflux medication, with only 237 (42%) referring cases for surgery.     

Regulation of alcohol consumption by the renin-angiotensin system: a review of recent findings and a possible mechanism of action.

The renin-angiotensin system has traditionally been associated with the regulation of fluid and electrolyte balance. In this review we summarize the data which ascribes a completely new function to this system, i.e., the regulation of alcohol consumption. In addition, we suggest a possible mechanism for this effect based on the concept of a satiety or stop process. The approach taken was to examine the effect on alcohol intake of a wide variety of drug, genetic, dietary, surgical and neurosurgical manipulations, each of which has a range of biological effects characteristic of that manipulation, but all of which share the common property of altering activity in the renin-angiotensin system. The effect of these manipulations on alcohol intake was most parsimoniously explained by reference to their ability to raise or lower activity in the renin-angiotensin system. Any intervention which modulates activity in this system, either directly or indirectly, is likely to have consequences for alcohol consumption.     

Molecular analysis of neuronal physiology by gene transfer into neurons with herpes simplex virus vectors.

A genetic analysis of mammalian neuronal physiology might now be possible due to the development of defective herpes simplex virus vectors, which allow gene transfer directly into mature neurons, in culture or in the adult brain. Genetically altered proteins that play critical roles in neuronal physiology, including those responsible for the generation of action potentials, synthesis and release of neurotransmitters, and signal transduction enzymes, can now be stably expressed in neurons. The effect of such altered proteins on neuronal physiology can therefore be examined, using the tools of modern neuroscience. Genetic manipulation is biochemically specific and stable, and can be targeted both to a particular cell type and to a particular subregion of the cell to yield insights into the molecular basis for specific brain functions.     

Cerebrovascular and metabolic perturbations in delayed heavy charged particle radiation injury

Focal heavy charged particle irradiation of the rabbit brain created defined lesions which were observable by nuclear magnetic resonance (NMR) and positron emission tomography (PET) imaging techniques. The lesions appeared approximately 9-11 months after left partial hemibrain irradiation with 30 Gy (230 MeV/u helium ions), and were restricted to the white matter tracts and deep perithalamic and thalamic regions. 82Rubidium PET and Gadolinium DTPA enhanced NMR imaging were used to detect blood-brain barrier perturbations. 18Fluordeoxyglucose PET studies demonstrated widespread decreases in cerebral glucose uptake in the cortex and thalamus of the irradiated hemisphere. NMR and PET imaging results correlated well with histological findings. Rabbits irradiated with 15 Gy did not demonstrate any abnormalities in the brain with sequential NMR scans through 14 months post-irradiation.