Application of biotechnology to the study of molluscan hosts of animal parasites

The intimate and complex relationship that exists between man and mollusc makes the group an ideal target for the application of biotechnology. The paper discusses and reviews the application of both the conventional and new molecular techniques to the study of the molluscan hosts of animal parasites. The remarkable advances in molluscan biology which have occurred during the past two decades as a consequence of conventional technological methods are noted and applications pertinent to problems in Southeast Asia are cited. Applications of new biotechniques, including those of molecular biology, to problems of the host-parasite interaction are discussed. Examples of how the new biotechnology may resolve present and future problems in applied malacology are presented.     

Pulmonary valve insertion during reoperation for tetralogy of Fallot

Our experience with pulmonary valve insertion during reoperation for residual lesions after initial open repair of tetralogy of Fallot in 15 patients is reported. Preoperatively, 14 patients were in moderate to severe congestive heart failure, and all 15 had decreased right ventricular (RV) function at cardiac catheterization. All 15 patients had pulmonary insufficiency but not as an isolated finding. The most common residual lesions encountered were ventricular septal defect in 9, tricuspid insufficiency in 11, and peripheral pulmonary arterial stenosis in 6. Tissue valves were inserted in all patients. Mean peak RV-left ventricular pressure ratio measured in the operating room decreased from 0.61 +/- 0.10 (+/- the standard deviation) to 0.47 +/- 0.17 (p less than 0.05). There were no operative deaths. At follow-up (mean, 33 months), all but 1 patient were in New York Heart Association Class I or II. Pulmonary valve insertion should be considered during reoperation for tetralogy of Fallot when pulmonary insufficiency and RV failure are present.     

Changes in left ventricular systolic wall stress during biventricular circulatory assistance

Extracorporeal membrane oxygenation (ECMO) reduces the systolic stress integral (SSI) in the normal left ventricle. We tested the hypothesis that the SSI does not decrease in poorly contracting, dilated, ejecting hearts during ECMO. In 14 sheep, four pairs of ultrasonic crystals measured changes in left ventricular (LV) wall thickness and three LV diameters. Volume calculations were validated by balloon distention of the ventricles after death (slope = 0.85; r = 0.85). SSI was measured during ECMO flows of 20 to 100 ml/kg/min in both normal and dilated, poorly contracting hearts produced by 30 minutes of warm ischemia. After warm ischemia, end-systolic elastance, an index of contractility, decreased from 8.3 +/- 0.6 mm Hg/ml to 2.9 +/- 0.4 mm Hg/ml (p = 0.001) and peak systolic pressure decreased from 47.4 +/- 0.7 mm Hg to 37.5 +/- 0.08 mm Hg (p = 0.01). In normal hearts, as ECMO flow increased, SSI decreased from 10.5 +/- 2.2 mm Hg.sec to 7.7 +/- 0.8 mm Hg.sec at 60 ml/kg/min (p = 0.001). However, in postischemic hearts, SSI progressively increased from 6.6 +/- 0.3 mm Hg.sec before ECMO to 12.4 +/- 1.8 mm Hg.sec at ECMO = 100 ml/kg/min. These studies indicate that the initial effect of ECMO on the poorly contracting, dilated heart increases LV wall stress and that the increase in stress is proportional to ECMO flow. The increase in stress is primarily due to an increase in afterload, which more than offsets decreases in systolic and diastolic volumes.     

APACHE II score and abdominal sepsis. A prospective study

Therapeutic trials for intra-abdominal sepsis require pretreatment stratification; physiologic scoring has been recently proposed for this purpose. We have prospectively tested the validity of one such scoring system, namely, the Acute Physiology and Chronic Health Evaluation (APACHE II). As part of a larger database, we correlated APACHE II scores with mortality in 100 patients hospitalized for generalized peritonitis or abdominal abscess. Use of steroids was recorded because of our suspicion that steroids increase mortality but blunt the physiologic response to sepsis. Thirty-one patients died, including 12 of 19 patients receiving steroids. Stepwise discriminant analysis revealed that the APACHE II score and steroid use were each independently associated with the rate of mortality. We report a prospective validation of pretreatment APACHE II scoring in abdominal sepsis. Steroid use is an independent risk factor.     

Corrosive oesophagitis: an analysis of 50 cases

A total of 50 consecutive patients who were treated in JIPMER Hospital between 1970 and 1981 for corrosive injuries of the oesophagus and stomach were analysed. There were 23 males and 27 females. All but seven presented with dysphagia due to an established stricture. In addition seven of them had associated stricture of the stomach. They were treated with either repeated dilatations or, in selected cases, oesophageal replacement. Perforation of the oesophagus is an important complication associated with oesophageal dilatation indicating the need for oesophageal replacement in multiple or long dense strictures. Results are quite satisfactory with both modalities of treatment. However, oesophageal replacement surgery, performed properly in selected cases, offers a permanent solution to these unfortunate victims.     

Choledochal cyst: case reports and current concepts

Choledochal cyst is an unusual but serious condition which most commonly affects Oriental people. Recent experience of three patients with this condition in whom diagnosis was made by ultrasound examination is reported. Cholangiography (ERCP or PTC) was performed in two of the cases to define the anatomy. All three cases were successfully managed by cyst excision and biliary reconstruction by Roux-en-Y hepaticojejunostomy. The rationale for and importance of cyst excision are discussed.