Quantitative assessment of variables that influence soft-tissue electrovaporization in a fluid environment

Objectives. To evaluate the process of soft-tissue electrovaporization and to study variables that affect tissue clearance rates in a laboratory setting, in order to identify parameters that can optimize transurethral electrovaporization of the prostate.Methods. Fresh bovine skeletal muscle, equivalent in impedance and surface properties to the human prostate, was submerged in 3.3% sorbitol solution and electrovaporized with a grooved monopolar electrode attached to the weighted arm of a linear actuator. The effects of excursion rate, applied mechanical load, power setting, electrode configuration, and generator performance on the volume of tissue removed, were assessed.Results. Tissue removal increased significantly when electrode excursion rate was slowed from 25 to 15 mm/s (P <0.05) and then to 10 mm/s (P <0.05); when the load was increased from 20 to 50 g (P <0.005); and when dial power was increased from 120 to 150 W (P <0.01). Tissue removal was generator dependent. There was no significant difference between the Force 40 and the Force 2 (P > 0.4), but a new computer-controlled constant power output generator (Force FX) did significantly improve tissue vaporization at an equivalent power setting (P <0.005 and P <0.01, respectively). Tissue removal was also dependent upon electrode configuration, with the VaporTrode-Grooved Bar removing significantly more tissue than either an ungrooved roller bar of equivalent size or 2-mm smooth roller ball, respectively, both after a single pass (P <0.001 and P <0.05) and after five repeated passes (P <0.05 and P <0.005). The histologic depth of tissue thermal effect was less than 1 mm, but it was 38% greater for the VaporTrode-Grooved Bar (0.68 mm) than for the standard cutting loop (0.5 mm, P <0.01).Conclusions. Using a novel method to quantify tissue removal, we have demonstrated that electrode configuration, excursion rate, applied load, power setting, and generator performance are interdependent factors that influence the efficacy of the electrovaporization process in a fluid environment.     

Effect of Zonisamide (CI-912) on a Synaptic System Model

The effect of the experimental antiepileptic drug zonisamide (1,2-benzisoxazole-3-methanesulfonamide, ZNS) on the trigeminal complex of cats was compared with the effect of established antiepileptic drugs. Intravenous administration of 10-40 mg/kg ZNS significantly depresses descending excitatory mechanisms, as well as segmental and descending inhibitory mechanisms, but has only a minor effect on segmental excitatory mechanisms. This spectrum of activity is similar to that of valproate, and suggests that ZNS should also be a broad-spectrum antiepileptic drug. In agreement with our experimental observations, it has been found that ZNS is effective against complex partial, generalized tonic clonic, and myoclonic seizures. The antiepileptic profile of ZNS in conventional screening tests resembles that of carbamazepine (CBZ) and phenytoin. However, CBZ exacerbates rather than prevents myoclonic seizures. Our experimental model thus provides a more accurate prediction of ZNS's clinical spectrum of activity. The relationship of these findings to the mechanism of action of antiepileptic drugs is discussed.     

Quantitative and qualitative changes of serum proteolytic activity in rats with liver damage induced by galactosamine

Serum proteolytic activity was determined in galactosamine-treated rats and in controls. Injection of the hepatotoxin at a dose of 400 mg/kg resulted in a 3.4-fold elevation in the serum proteolytic activity, while AST (aspartate aminotransferase), ALT (alanine aminotransferase) and bilirubin were increased by factors of 3.9, 8.8 and 4.5, respectively. Studies with proteinase inhibitors revealed that the serum proteolytic activity was partially metal-dependent as well as puromycin and antipain sensitive. Differences in susceptibility to a combination of N-ethylmaleimide and antipain indicated presence of different proteolytic systems in the sera of liver damaged and control rats. Separation of serum proteinases by gel filtration showed that the galactosamine-intoxicated rat serum contained activity which did not appear in the control serum. This activity was partially metal dependent, antipain and N-ethylmaleimide sensitive, and was more susceptible to dithiothreitol than the control activity. These findings demonstrate that hepatocellular damage induced by galactosamine caused not only an increase in serum proteinases, but was also associated with the appearance of enzymes not normally released by the liver of untreated animals.Abbreviations AP alkaline phosphatase - TBil total bilirubin - AST aspartate aminotransferase - ALT alanine aminotransferase - GGT gamma-glutamyltranspeptidase - BiAc bile acids - PrAm primary amines - ProAc proteolytic activity     

Weight percentile at birth. I. Clinical data of pregnancy and relevance for early childhood development

The influence of the weight percentile at birth on childhood development was examined in a prospective study of 847 singleton pregnancies. In the first two years of life significant relationships between the birth weight percentiles and the infant's development could be proven, while at the age of four social factors were predominant. Though various clinical data in pregnancy and delivery were related to fetal growth, such as weight of the mother, previous abortions and diseases, additional biochemical and biophysical information is desirable for early recognition of intrauterine growth disorders.     

Health lifestyles and self-direction in employment among American men: A test of the spillover effect

This paper examines whether American males with a high degree of control over their work situation pursue healthy lifestyles and rate their physical health more positively than those who score low on occupational self-direction. That is, are persons who control their work more likely to also try to control their health through living in a particularly healthy manner? We found that there was no support for a spillover effect from high occupational self-direction to enhanced participation in health lifestyles or more positive self-rated health. The findings suggest health lifestyles have spread throughout occupational work groups in the U.S. and support research that maintains such lifestyles have spread across social strata in America.     

Auer rod positive dysmyelopoietic syndrome

Twenty-five patients with refractory anemia with excess blasts (RAEB) were studied. Five of these patients showed Auer rods in their myeloblasts, but met other criteria for RAEB. Median survival of the Auer rod-positive group was 14 months (range 2–27) from diagnosis with survival of 7 months after Auer rods were first observed. Median survival for the Auer rod-negative group was 12 months. Two patients developed overt acute leukemia, both from the Auer rod-negative group. The clinical course of Auer rod-positive RAEB, like that of Auer rod-negative RAEB, was one of progressive bone marrow failure complicated by infection, serious bleeding and the development of absolute transfusion requirement. These findings suggest that Auer rod-positive RAEB is a morphologic variant dysmyelopoietic syndrome that may pursue a similar clinical course to Auer rod-negative disease. Formulation of a separate treatment approach for those RAEB patients who possess Auer rods would appear ill advised.     

Structural analysis of poly(3-alkylthiophene)s

Poly(3-hexylthiophene) (PT6), poly(3-octylthiophene) (PT8), poly(3-decylthiophene) (PT10) and poly(3-dodecylthiophene) (PT12) were synthesized by electrochemical and chemical polymerization. Investigation of these polymers by means of gel permeation chromatography indicates that the polymers prepared from the different monomers under similar conditions do not differ substantially considering molecular weight and molecular weight distribution. Bimodal distributions were found for electropolymerized polymers, and with increasing polymerization time, the high-molecular-weight and probably highly branched fraction increased relatively to the low-molecular-weight fraction. The microstructure of the polymers was investigated by nuclear magnetic resonance, and it has been found that the polymers exhibit more types of structural units than expected from a simple coupling of adjacent thiophene moieties in 2,5′-positions. Chemical oxidation with iron trichloride in chloroform gave soluble, high-molecular-weight poly(3-alkyl-thiophene)s with a rather low amount of irregular couplings, and these more regular polymers exhibited a higher degree of crytallinity. Room temperature conductivities of the oxidized polymers were between 0,1 and 30 S/cm depending on the polymerization conditions, but these values were rather independent of the length of the alkyl substituent.