An evaluation of standardizing target ventilation for eucapnic voluntary hyperventilation using FEV1.

Athletes are required to provide objective documentation of exercise-induced bronchoconstriction (EIB) to use beta2-agonists during Olympic competition. A positive response to bronchial provocation by eucapnic voluntary hyperventilation (EVH) is considered acceptable confirmation of EIB. Thirty times forced expiratory volume in the first second (FEV1) is recommended as EVH target ventilation (TV), an intensity intended to estimate 85% of maximal voluntary ventilation (MVV). There is a paucity of data examining the accuracy of predicting MVV from FEV1 in elite athletes. The purpose of this study was to evaluate the efficacy of 30 x FEV1 as standardized EVH TV. Maximal minute ventilation during exercise (VEmax) and pulmonary function of 78 elite winter athletes (25 males, 53 females; 25 EIB positive, 53 normal) were analyzed retrospectively. Adequacy and variability of the equation was ascertained by examining the ratio of EVH TV (30 x FEV1) to VEmax. VEmax was 99+/-11% of predicted MVV (35 x FEV1) and was positively related (r=0.85, p < or = 0.05). TV was 88+/-9% of VEmax (range: 64-109). For elite athletes, the high variability in 30 x FEV1 to standardize TV for EVH may result in under-diagnosis for low-end outliers. Since VEmax of elite endurance athletes is typically known (via maximal aerobic testing) we recommend 85% VEmax as a more accurate and reliable method to establish EVH TV for this group; if VEmax is not available, then 85% of measured MVV may be used.     

New Technique for the Use of a Precision Attachment in the Fabrication of a Cast Crown/Core and Post Unit: Procedures and Case Report

A case report of a prefabricated cast post system, Flexi-Cast, is presented. This tech-nique provides maximium retention of the post in the root and crown to a core by incorporation of a prefabricated split-shank threaded post with an attachment sleeve. Clinically this appears to be a simple predictable technique for the fabrication of a crown/core as a single unit.     

Induced chorioretinal venous anastomosis in experimental retinal branch vein occlusion.

Iatrogenic retinal vein to choroidal vein anastomoses were created using laser photocoagulation in six of seven dog eyes in which a partial branch retinal vein occlusion had previously been created photochemically. A similar attempt to create an anastomosis was made in six control eyes in which no branch vein occlusion was present. In the eyes in which a branch retinal vein had been created, a venous chorioretinal anastomosis appeared to be present by 3 to 6 weeks. In three control eyes similar venous anastomosis was created; however this took 6 to 8 weeks to develop and was of much smaller calibre than the one that developed in the presence of a partial branch retinal vein occlusion. No adverse complications were noted in the period of the study (3 months). This study demonstrates that chorioretinal venous anastomoses can be created and may be of use in the treatment of partial retinal vein occlusions that show signs of progression.     

Alteration of benzodiazepine receptors in mouse cerebellum following methylazoxymethanol treatment during development

The specific binding of [3H]flunitrazepam was studied to biochemically specify the morphological alterations induced in mouse cerebellum by a single injection of an antimitotic agent, methylazoxymethanol (MAM) performed at the beginning of the postnatal life. The MAM injection causes a general reduction of the benzodiazepine receptors in the adult mice which is particularly severe in mice having been injected the 1st day of postnatal life (so-called MAM0 mice) as compared to animals injected the 5th day (MAM5 mice): in MAM0 mice the benzodiazepine receptor is reduced to half of the control value. The affinity of the benzodiazepine towards its receptor was not affected and the topographic and biochemical action of MAM in the central nervous system was ascertained. Correlations could be made between the biochemical modifications and the morphological alterations otherwise described.     

Molecular cloning of the human geneSUVCC3 associated with the formation of DNA-protein crosslinks following exposure to solar UV radiation

DRP 153 cells, which are hypersensitive to solar UV and deficient in the formation of DNA-protein crosslinks (DPC) following irradiation, were transfected with human DNA and a secondary transformant obtained in which a normal DPC response and solar UV sensitivity reestablished. DNA from this secondary transformant was used to construct a genomic DNA library from which a recombinant phage was isolated containing the human gene capable of restoring a normal DPC response and solar UV sensitivity to DRP 153. This gene has been designatedSUVCC3 to denote solar UV cross-complementing gene number 3.     

Effects of plume produced by the Nd:YAG laser and electrocautery on the respiratory system

Sprague-Dawley rats were exposed to Nd:YAG laser exhaust (contact and noncontact) as well as to electrocautery exhaust passed through smoke evacuation filters. Exposure periods for each group were equal and increasing in time. Histologic analysis revealed alveolar congestion and emphysematous changes in all modes. Controls exhibited similar change but to a milder degree. It appears that any plume produced by lasers or electrosurgical devices produces pathologic change in rat lungs and that effective smoke evacuation will help control these effects. © 1993 Wiley-Liss, Inc.