The value of colonoscopy in schistosomal, tuberculous, and amebic colitis. Two-year experience

Forty-six patients were diagnosed as having schistosomal, tuberculous, or amebic colitis over a two-year period using colonoscopy and biopsy. Both schistosomal and tuberculous colitis could be diagnosed by characteristic endoscopic and histologic features in the majority of cases. Colonoscopy provided the added advantage of endoscopic polypectomy at the diagnostic session itself. The yield of granulomas in tuberculous lesions was 100 percent, although acid-fast bacilli could not be recovered from any. The endoscopic picture of amebic colitis often resembles that of inflammatory bowel disease; hence endoscopic biopsies are of paramount importance in establishing a correct diagnosis, especially in developing countries where both diseases exist with considerable frequency.

Primary gastrointestinal lymphoma complicated by common bile duct obstruction: report of two cases

This report describes two cases, a case of primary small intestinal lymphoma and a case of gastroduodenal lymphoma both producing obstructive jaundice due to invasion of the common bile duct. Oesophagogastroduodenoscopy revealed the lesions and the endoscopic biopsies confirmed the diagnosis of lymphoma in both the cases. Ultrasound examination of the biliary system, followed by percutaneous transhepatic cholangiography, delineated the dilated biliary tree with distal obstruction of the common bile ducts. While radiotherapy alone was sufficient in the case of primary small intestinal lymphoma; drainage procedures were required in the case of gastroduodenal lymphoma to relieve the obstruction of the common bile duct.

The role of gastrointestinal endoscopy in a developing country

Eight-thousand-six-hundred-and-eighty patients were examined endoscopically over a period of six years. Significant pathological lesions were detected in 79.6% of the cases. While duodenal ulcers were seen at the same frequency as in the West, the number of gastric ulcers were considerably fewer, the ratio of gastric to duodenal ulcer being 1:8.4. Gastric cancer was also observed less commonly than in the West, but gastric lymphoma constituted 21% of all gastric malignancies. By endoscoping all bleeders within 24 hours we were able to identify the source of bleeding in 90.9% of the cases, and a lesion was detected in 96.8%. Direct visualisation of the duodenal and jejunal mucosa supported by histological examination was of paramount importance in the early detection of Immunoproliferative Small Intestinal Disease (IPSID) and its differentiation from other diseases such as tuberculosis, bilharzial jejunitis and Crohn's disease which are seen in our population.

Mechanics of left ventricular aneurysm

When a coronary artery is significantly occluded, the left ventricular myocardial segment, which is perfused by that coronary artery, will become ischaemic and even irreversibly infarcted. An acute infarct has very low stiffness and if it involves the entire wall there is a risk of rupture; however, in the absence of such a critical situation, fibrous tissue is laid into the infarcted myocardial segment. Such an infarcted fibrotic myocardial segment will not be able to contract, and so generate tensile stress. The surrounding intact myocardium will contract and generate wall stress, thereby developing a high intra-chamber systolic pressure; the chronically infarcted and fibrotic segment will have to sustain this high chamber pressure. Its loss of contractility and the resulting reduced systolic stiffness relative to the intact segment, will cause it to deform into a bulge; this is an aneurysm. When a left ventricular chamber with an aneurysm contracts during the systolic phase, some blood also goes into the aneurysm, and this decreases the stroke volume; since the aneurysm wall is passive, stagnant blood flow prevails in the aneurysm itself, which in turn can give rise to the formation of a mural thrombus. These serious consequences provide a justification for the analysis of an infarcted left ventricular chamber, in order to predict the size of the aneurysmic bulge. Such an analysis is presented in this paper. To determine the left ventricular wall deformation, and the stress arising from infarction of a wall segment (which leads to a ventricular aneurysm) the left ventricle is modelled here as a pressurized ellipsoidal shell. Deformations of infarcted wall segments are computed for several damaged wall-thicknesses in left ventricles of different shapes. The analysis involves a derivation of equations for wall-stress equilibrium with the chamber pressure, and myocardial incompressibility before and after infarct formation. The equations are solved by the Newton-Raphson method (using elliptical integrals of the first and second kind). Of significance are the prognostic implications of the results, presented in the form of graphs, showing the dependence of tensile stress and the bulge of infarcted wall-segments, on the extent of damaged wall-thickness and the angle of infarct. Scaled illustrations of the bulge shapes, for various degrees of infarcts, are provided. The results indicate that for rupture of the ventricle, the percentage of infarcted wall-thickness and the shape of the ellipsoidal left ventricular chamber play more dominant roles than the angle-of-damage, or the extent of the infarct.

Primary gastrointestinal lymphoma in Kuwait. An 11-yr retrospective analysis of 108 cases

One hundred and eight cases of primary gastrointestinal lymphoma from the files of Kuwait Cancer Control Center over a period of 11 yr were analysed retrospectively. The occurrence was 47 in the proximal small intestine, 38 in the stomach, 18 in the distal ileum and five in the colon and rectum. The majority of the patients were in stage III. Using a modified Rappaport's classification, lymphocytic lymphoma was the commonest histologic type (60%) as compared to histiocytic lymphoma (19%). Four patients had early IPSID (immunoproliferative small intestinal disease). The 'Western' type of lymphoma occurred in the fourth decade while the 'Mediterranean' type occurred in the third decade of life. The latter occurred more commonly among people of low socioeconomic background. Chemotherapy was the single most effective mode of treatment. Addition of surgery, radiotherapy or both did not improve the 2-yr survival but did improve the 5-yr survival.

Inflammatory bowel disease in Kuwait

Inflammatory bowel disease is considered to be rare or nonexistent in some Arab countries. During a period of 6 years, 91 patients with ulcerative colitis and 17 with Crohn's disease were seen for initial diagnosis in the Gastroenterology Department of Amiri Hospital, which serves 55% of the population of Kuwait. From this group, 43 patients with ulcerative colitis and 14 patients with Crohn's disease were followed up for an average of 30.9 months. In the remaining 51 patients, the diagnosis was established in the same manner as in this series, but these patients were sent back to the referring physicians and therefore were not available for follow-up. The severity of the disease in the majority of patients with ulcerative colitis was mild to moderate. Nine of 14 patients with Crohn's disease underwent surgery as a diagnostic procedure in an acute abdominal emergency or for treatment of complications. The duodenum was involved in two patients with Crohn's disease and the endoscopic picture and histology of these were initially interpreted as immunoproliferative small intestinal disease which is highly prevalent in this area. We suggest that the assumption that inflammatory bowel disease is uncommon in our population is wrong.

Performance Evaluation of Induced Gas Flotation Machine Through Mathematical Modeling

Oil removal from produced water was studied in an induced gas flotation machine to (1) determine influential parameters in oil removal efficiency, (2) develop efficiency models, and (3) predict machine settings for optimal performance. Chemical concentration and flow rate were found to be the performance. Chemical concentration and flow rate were found to be the most important variables affecting oil removal efficiency.

Introduction

Standards have been promulgated recently by the U.S. Environmental Protection Agency for oil and grease content of offshore produced-water discharges. Other instances where water quality requirements must be met are (1) steam generator feedwater in thermal recovery operations, (2) flood water for low-permeability oil reservoirs, and (3) underground disposal of waste waters containing viscous oils and/or excessive suspended solids.Dissolved gas flotation cells have been used extensively as the final step in oil removal from produced water. Shell Oil Co. has used induced produced water. Shell Oil Co. has used induced gas flotation (IGF) machines in produced-water service since 1970. Degner reviewed the application of induced air flotation technology to industrial wastewater contaminant removal. He discussed the operational parameters and flotation cell design and their relation to removal efficiency. These cells now are used principally in minerals beneficiation. However, no published information was available on full-scale IGF machine processing of actual produced water. As such, it was felt that a systematic study could lead to improved design for oil/water separation. Optimal design and operation of these machines could help meet offshore discharge regulations and would result in lower operating costs for treating produced water. A program was initiated to study a full-scale four-cell experimental IGF machine. This machine was purchased from WEMCO Div. of Envirotech Corp. It was installed in Shell's Coalings, CA, oil field to (1) determine the parameters that influence oil removal efficiency in parameters that influence oil removal efficiency in IGF machines, (2) develop performance models and curves based on these parameters, (3) predict machine parameter settings for optimal performance, (4) develop a mathematical model for performance, (4) develop a mathematical model for power usage, and (5) develop economical methods of power usage, and (5) develop economical methods of operation.The study was conducted in two phases. The initial-phase test results determined parameters that significantly influence oil removal efficiency. These parameters were studied in more detail in the final parameters were studied in more detail in the final phase. This allowed regression models to be built for phase. This allowed regression models to be built for predicting oil removal percentage at each stage. predicting oil removal percentage at each stage. These models were used to generate several plots of oil removal efficiency as a function of important parameters. Optimization runs at various flow rates parameters. Optimization runs at various flow rates indicated machine settings for maximum oil removal efficiency. A total cost expression was developed by combining the total rotor horsepower model with chemical costs derived from the oil removal efficiency model for the overall machine.

JPT

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Colorectal carcinoids in South India

Twenty cases of colorectal carcinoids are reviewed in this report. Among the South Indian Asiatic, the colorectal carcinoids are apparently more common than appendicular and small intestinal carcinoids. The data obtained in this survey and the experience in America, citing increased incidence of such carcinoids in Negroes, suggest that racial factors are responsible for certain differences. The tendency to involve younger age groups and many cases having aggressive potentialities are other variations encountered in this review. A brief summary of its characteristic histopathology is given.

A three-dimensional analytical (rheological) model of the human left ventricle in passive-active states. Nontraumatic determination of the in vivo values of the rheological parameters

In this paper a three-dimensional continuum model of a mammalian left ventricle is formulated. The stresses in the model satisfy the conditions of zero stress on the outer (epicardial surface-representing) boundary. The strains of the model are obtained from the actual dynamic geometry measurements (obtained from cineangiocardiography). Since the left ventricular muscle is incompressible, the dilatational strain is zero and hence the (three-dimensional) deviatric stress components are related to the corresponding strain components by Maxwell and Voigt rheological model analogues of one-dimensional systems; the parameters of the model are series and parallel elastic (SE, PE) elements and the contractile element (CE) (representing the sarcomere). The incorporation of the rheological features of the cardiac muscle into the three-dimensional constitutive equations (for the three-dimensional continuum model of the left ventricle) is a feature of this paper. A procedure is presented to determine the parameters of the constitutive equations (i.e., the SE, PE, and the parameters of the force-velocity relation for the CE) for the left ventricle of a subject from data on the dimensions and chamber pressure of the left ventricle. The values of these parameters characterize the rheology of the left ventricular muscle of the subject. In order to demonstrate clinical application of the analyses, in vivo data of the subjects' left ventricular pressure and dimensions are obtained, and the analyses are applied to the data to determine (for each subject) the values and characteristics of the elastic elements and CEs.