Endosonographic characteristics of perigastrointestinal lymphnodes studied ex-corpore.

OBJECTIVES: Assessment of morphological characteristics of lymphnodes studied ex-corpore by echoendoscopy--shape, sharpness of limits, echogenicity and dimensions--to categorize them either as metastatic or non-metastatic. MATERIAL AND METHODS: Fifty-four lymphnodes were studied. They were identified and studied by echoendoscopy in fresh surgical specimens of oesophagus, stomach and rectum. Eight nodal characteristics were evaluated. The data obtained were studied by multivariate analysis using the logistical estimate method in two different statistical models. RESULTS: In model 1, logistical estimate demonstrated that well-defined limits (WDL) of the lymphnodes and the association of hypoechogenicity and round shape were the most significant variables suggesting the presence of invasion. In model 2, the most significant variables were WDL, round shape and association of round shape with WDL. The first model had a high sensitivity of 93.1% and specificity of 68% whereas the second model had a greater specificity of 84%, with a slight fall in sensitivity. CONCLUSION: These models might have an application to clinical practice particularly in the pre-operative assessment of patients with oesophageal carcinoma, gastric carcinoma or rectal carcinoma.

Conversion factors in laparoscopic cholecystectomy for acute cholecystitis.

BACKGROUND/AIMS: Although laparoscopic cholecystectomy already occupies an important role in acute cholecystitis, a high rate of conversion continues to be referred to in the series published. One of the objectives of this study is to assess the preoperative factors that might lead to conversion. METHODOLOGY: 100 laparoscopic cholecystectomies for acute cholecystitis were studied of which 24 were converted. Several parameters are taken into consideration: age, sex, ASA, echographic data, bacteriological examination of the bile, time elapsing between diagnosis and surgery, morbidity and mortality. RESULTS: The analysis made in relation to the preoperative, predetermining factors with regards to the converted cases provided the following elements in unvaried analysis: Preoperative existence of: "plastron" gallbladder (P < 0.002), temperature above 38 degrees C (P < 0.04), leucocytosis (P < 0.02)), time elapsing between diagnosis and surgery (P < 0.005), presence in the echography of pericholecystic liquid (P < 0.0005) and edema (P < 0.001); Klebsiella in the gallbladder bile (P < 0.005). Age (P = 0.136), sex (P = 0.992), associated diseases (P = 0.961), and gallbladder pathology (P = 0.282) did not present statistical differences that would prevent valid conclusions. In multi-varied analysis it was only possible to consider as independent factors the leucocytosis and the time between diagnosis and surgery. CONCLUSIONS: Laparoscopic cholecystectomy is a safe and efficient technique in the treatment of acute cholecystitis, which should constitute the first choice of treatment for this disease. However, it should be carried out within the first 4 days following surgical diagnosis.

Metal and physico-chemical variations at a hydroelectric reservoir analyzed by Multivariate Analyses and Artificial Neural Networks: environmental management and policy/decision-making tools.

This paper compared and evaluated seasonal variations in physico-chemical parameters and metals at a hydroelectric power station reservoir by applying Multivariate Analyses and Artificial Neural Networks (ANN) statistical techniques. A Factor Analysis was used to reduce the number of variables: the first factor was composed of elements Ca, K, Mg and Na, and the second by Chemical Oxygen Demand. The ANN showed 100% correct classifications in training and validation samples. Physico-chemical analyses showed that water pH values were not statistically different between the dry and rainy seasons, while temperature, conductivity, alkalinity, ammonia and DO were higher in the dry period. TSS, hardness and COD, on the other hand, were higher during the rainy season. The statistical analyses showed that Ca, K, Mg and Na are directly connected to the Chemical Oxygen Demand, which indicates a possibility of their input into the reservoir system by domestic sewage and agricultural run-offs. These statistical applications, thus, are also relevant in cases of environmental management and policy decision-making processes, to identify which factors should be further studied and/or modified to recover degraded or contaminated water bodies.

[Laparoscopy or laparotomy in acute cholecystitis (200 cases). Comparison of the results and factors predictive of conversion]. / Laparoscopie ou laparotomie dans la cholécystite aiguë (200 cas). Comparaison des résultats et facteurs prédisposant à la conversion.

STUDY AIM: The aim of this prospective study was to compare the results of cholecystectomy for acute cholecystitis through laparoscopic and open approach and to assess factors responsible for conversion into laparotomy. PATIENTS AND METHODS: From January 1991 to October 1997, 200 patients with calculous acute cholecystitis were operated on in the same center, 100 through laparoscopy and 100 through laparotomy. Choice between these two procedures was only dependent on the disresponsibility of videolaparoscopic material. Comparison between laparoscopy and laparotomy groups concerned postoperative mortality and morbidity rates, hospital stay duration and late results. Intraoperative conversion into laparotomy occurred in 24 patients and factors responsible for conversion were assessed with univaried and multivaried analysis. RESULTS: Both groups were comparable with regard to sex ratio, age, ASA score but associated diseases incidence, plastron, fever above 38 degrees C and leucocytosis were significantly more frequent in the laparotomy group and delay between diagnosis and surgery was significantly longer in the laparoscopic group. There were two postoperative deaths in the laparotomy group, 0 in the laparoscopic group (NS). Morbidity rate was higher (32% versus 10%) (p = 0.0002) and hospital stay longer (12 +/- 10 days, versus 5 +/- 3) in the laparotomy group (p = 0.00005). Late results were similar in both groups. Conversion rate into laparotomy was 24%. Factors predisposing significantly to conversion were in univaried analysis: plastron, fever above 38 degrees C, leucocytosis, delay between diagnosis and surgery above 4 days, presence on ultrasonography of pericholecystic liquid and gallbladder wall edema, presence of "Klebsiella" in gallbladder bile. With multivaried analysis, leucocytosis and delay between diagnosis and surgery were the only independent factors. CONCLUSION: Videolaparoscopic cholecystectomy is a safe and efficient technique in the treatment of acute cholecystitis, with a lower postoperative morbidity rate and a shorter hospital stay. Conversion rate into laparotomy is significantly dependent on leucocytosis and delay between diagnosis and surgery. Laparoscopic cholecystectomy should be performed as soon as possible in acute cholecystitis.