Congenital esophageal stenosis presenting as noncardiac,esophageal chest pain

Summary A case of a 31-year-old female with congenital esophageal stenosis presenting with symptoms of chest pain caused by esophageal dysmotility is described. The involved segment in congenital esophageal stenosis has a characteristic thickening of the muscularis propria layer, as seen by EUS examination. In these patients, symptoms of dysphagia can be managed with esophageal dilation and noncardiac esophageal chest pain responds to pharmacotherapy with diltiazem.The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official policy or reflecting the views of the Army or the Department of Defense.     

Nonsurgical repair of perforation defects. Internal matrix concept.

The internal matrix concept of perforation repair offers distinct advantages over classic techniques. The biocompatible matrix allows control of the repair material. The technique sensitivity involved with placement of the repair material is reduced and contamination of the restorative material with hemorrhage is prevented. In accessible locations perforations can be repaired predictably and, by comparison, the prognosis is improved greatly. Fewer surgeries or surgical alterations of teeth will be necessary, thus reducing the cost of treatment. A higher percentage of existing crowns can be salvaged if surgical alteration of the tooth is prevented. Microsurgical techniques currently are being developed and researched that may allow nonsurgical repair of inaccessible perforations. The scope of endodontic therapy, therefore, will be expanded.     

Case Report: Giant choledochal cyst

We report an adult female with a rare giant choledochal cyst. The patient presented following a normal pregnancy with the classical triad of an abdominal mass associated with jaundice and right upper quadrant abdominal pain. The cyst was excised using an intramural technique and biliary reconstruction achieved with a Roux-en-Y hepaticojejunostomy. Our patient has remained well with no evidence of malignancy over a 12 year review period. The aetiology and current management of this condition are discussed.     

Determination of optimal cryoprotectants and procedures for their addition and removal from human spermatozoa

The objective was to test the hypothesis that the optimal cryoprotective agent for cryopreservation of human spermatozoa would be a solute for which cells have the highest plasma membrane permeability, resulting in the least amount of volume excursion during its addition and removal. To test this hypothesis, theoretical simulations were performed using membrane permeability coefficients to predict optimal procedures for the addition and removal of a cryoprotectant. Simulations were performed using data from four different cryoprotectants: (i) glycerol, (ii) dimethyl sulphoxide, (iii) propylene glycol and (iv) ethylene glycol. Thermodynamic formulations were applied to determine approaches for the addition and removal of 1 M and 2 M final concentrations of cryoprotectant, allowing the spermatozoa to maintain a cell volume within their osmotic tolerance limits. Based on these data, ethylene glycol was predicted to be optimal for minimizing volume excursions among the solutes evaluated. These predictions were then experimentally tested using glycerol as the control cryoprotectant and ethylene glycol as the experimental cryoprotectant. The results indicate that there was a higher (P < 0.05) recovery of motile spermatozoa after cryopreservation when using 1 M ethylene glycol than with 1 M glycerol, supporting the hypothesis that use of the cryoprotectant for which the cell has the highest permeability will result in higher cell survival.      

The effects upon the activity of hand and forearm muscles of intracortical stimulation in the vicinity of corticomotor neurones in the conscious monkey

Summary Corticomotor (CM) neurones were identified in three conscious macaque monkeys by the presence of post-spike facilitation (PSF) in spike-triggered averages of e.m.g. recorded from intrinsic hand and forearm muscles during performance of a precision grip task. Post-spike effects were compared with those produced by single-pulse intracortical microstimulation (ICMS), with strengths of 4–20 A, delivered at the site of 47 CM cells. Most muscles facilitated by a CM cell were also facilitated by ICMS at the site of the cell. ICMS effects were stronger: at 10 A, the amplitude of ICMS-evoked facilitation was on average 2.8 times greater than PSF, and 6.9 times greater at 20 A. Onset latency of ICMS-evoked facilitation was consistently longer (by 1.7 and 1.3 ms at 10 and 20 A respectively) than PSF, and it is suggested that this results from the indirect, trans-synaptic excitation of CM cells by ICMS. Post-spike suppression was rarely seen (7/421 compared to 105/421 cases of PSF). In contrast, suppression and facilitation were equally common in response to ICMS. The synaptic mechanisms underlying these effects were explored in 5 anaesthetised macaque monkeys. ICMS facilitated a greater proportion of the tested muscles than did the CM cell recorded at the stimulus site. The results suggest the juxtaposition in the motor cortex of CM neurones with different muscle fields. The merits of STA and ICMS for exploring cortical organisation are discussed.