Esophageal reconstruction with free jejunal grafts: an experimental study

Replacement of a long segment of esophagus for esophageal atresia or severe stenosis remains a special problem in children. The following studies were designed to test the hypothesis that a section of small bowel without serosa could survive as a free autologous transplant to replace part of the mediastinal esophagus. Laparotomy was performed in 20 adult cats, a loop of small bowel was resected and an end-to-end jejunojejunostomy was completed. The serosa of the resected bowel was removed and the mucosa-muscularis graft was used to replace a segment of the middle esophagus that was resected via a right thoracotomy. The interposed graft was entirely wrapped with adjacent skeletal muscle flaps. Postoperative studies include barium swallow and cine esophagograms, histology and blood vessel casts. Results are presented which show anatomical and functional survival of 16 grafts without blood vessel anastomoses or intrinsic vascular pedicles.     

Outcome of unsuspected pneumococcemia in children not initially admitted to the hospital

The records were reviewed of 97 episodes of unsuspected pneumococcemia in children not initially admitted to the hospital. Antimicrobial agents were prescribed at the first visit for 46 children; at the second visit 37 of them were improved and nine were not. No antimicrobial agents were prescribed at the first visit for 51; at the second visit 16 of these patients were improved and 35 were not. Pneumococcemia persisted in two treated children and in 13 untreated children. Meningitis was identified later in four children (two treated and two untreated). Although pneumococcemia in children may be a transient event, it may also persist or result in meningitis or other localized infections.     

Large-Scale CFD Data Handling in a VR-Based Otorhinolaryngological CAS-System using a Linux-Cluster

Many of the operations to eliminate complaints concerning respiration impairments fail. In order to improve the success rate, it is important to recognize the responsiveness of the flow field within the nasal cavities. Therefore, we are developing a computer assisted surgery (CAS) system that combines computational fluid dynamics (CFD) and virtual reality (VR) technology. However, the primary prerequisite for VR-based applications is real-time interaction. A single graphics workstation is not capable of satisfying this condition and of simultaneously calculating flow features employing the huge CFD data set. In this paper, we will present our approach of a distributed system that relieves the load on the graphics workstation and makes use of an off-the-shelf parallel Linux cluster calculating streamlines. Moreover, we introduce first results and discuss remaining difficulties.     

Damage to cochlear efferents following AF64A intoxication

Damage to cochlear efferents in chinchillas was assessed using transmission electron microscopy following unilateral treatment with the cholinotoxin ethylcholine mustard aziridinium ion (AF64A). AF64A was diluted in artificial perilymph to concentrations ranging from 0.5 to 100 microM. Survival times ranged from 1 to 12 weeks. At concentrations above 10 microM, widespread damage was noted to efferent fibers within the inner spiral bundle (ISB), tunnel spiral bundle (TSB), tunnel radial fibers (TRF) and efferent terminals at the base of OHCs. This damage included degeneration of fibers and terminals, delamination of mitochondria, vacuolization, and loss of cell membrane. However, at high concentrations, non-specific damage was also noted as thinnings or discontinuities of the membrane of OHCs and afferent fibers. At concentrations between 3 and 10 microM, selective damage was observed to efferent fibers within the ISB, TSB, TRF, and to terminals at the base of the OHCs, with all other structures appearing normal. At concentrations of 0.5 and 1 microM, damage was limited to efferent fibers within the TSB and ISB below the inner hair cells. In general, insult was greatest to middle- and basal-turn efferents, and longer survival times did not produce greater damage to, or loss of, efferents. These data suggest that at low concentrations, AF64A produces a partial yet selective degeneration of cochlear efferents within both the medial and lateral tracts, and that at the lowest concentrations used in these studies, AF64A produces a preferential insult on lateral olivocochlear efferents.     

RS-102221: a novel high affinity and selective, 5-HT2C receptor antagonist

The 5-HT2C receptor is one of three closely related receptor subtypes in the 5-HT2 receptor family. 5-HT2A and 5-HT2B selective antagonists have been described. However, no 5-HT2C selective antagonists have yet been disclosed. As part of an effort to further explore the function of 5-HT2C receptors, we have developed a selective 5-HT2C receptor antagonist, RS-102221 (a benzenesulfonamide of 8-[5-(5-amino-2,4-dimethoxyphenyl) 5-oxopentyl]-1,3,8-triazaspiro[4.5]decane-2,4-dione). This compound exhibited nanomolar affinity for human (pKi = 8.4) and rat (pKi = 8.5) 5-HT2C receptors. The compound also demonstrated nearly 100-fold selectivity for the 5-HT2C receptor as compared to the 5-HT2A and 5-HT2B receptors. RS-102221 acted as an antagonist in a cell-based microphysiometry functional assay (pA2 = 8.1) and had no detectable intrinsic efficacy. Consistent with its action as a 5-HT2C receptor antagonist, daily dosing with RS-102221 (2 mg/kg intraperitoneal) increased food-intake and weight-gain in rats. Surprisingly, RS-102221 failed to reverse the hypolocomotion induced by the 5-HT2 receptor agonist 1-(3-chlorophenyl)piperazine (m-CPP). It is concluded that RS-102221 is the first selective, high affinity 5-HT2C receptor antagonist to be described.