Impact of natural control agents of the citrus leafminer Phyllocnistis citrella on lemon trees varies among seasons.

Studies on insect natural enemies and their effects on host populations are of immense practical value in pest management. Predation and parasitism on a citrus pest, the leafminer Phyllocnistis citrella Stainton, were evaluated by sampling over 3 years in four locations within a world leading lemon producing area in Northwest Argentina. Both mortality factors showed seasonal trends consistent across locations, with predation exerting earlier and more sustained pressure than parasitism, which showed wider seasonal variations. The dominant parasitoids, native Cirrospilus neotropicus and introduced Ageniaspis citricola, showed different seasonal trends: C. neotropicus was dominant in spring whereas A. citricola superseded it in autumn and winter. Although parasitism rates were relatively low, the native C. neotropicus revealed favourable features as potential control agent, by showing density-dependence, parasitism rates comparable with those of the specific A. citricola during part of the cycle, and earlier synchronization with the host. The study provides highly relevant information for a sustainable management of this worldwide pest, for which biological control is considered the best long-term option.

Scanning electron microscopy of superficial defects in Twisted files and Reciproc nickel-titanium files after use in extracted molars.

AIM: To evaluate the usage and superficial defects in size 25, 0.08 taper Twisted files (TF) and R25 Reciproc files after root canal instrumentation. METHODOLOGY: One hundred and twenty mandibular molars with root canal curvature, ranging from 15° to 30° and a 4-5 mm radius, were randomly divided into two groups according to single-file instrumentation: size 25, 0.08 taper TF or R25 files. A total of fifteen files per group were evaluated before and after three, six, nine and 12 uses. The instruments were fixed in custom-made holders and photographed using scanning electron microscopy at ×260 to ×1200 magnifications. The presence of superficial defects (plastic deformation, microcracks, fracture, craters, disruption of the cutting edges and blunt edges) was scored from the pre- and post-usage photographs. Chi-squared test was used to analyse differences after usages in both groups individually. Two-way anova was used to analyse differences between both instruments. The level of significance for all analyses was 5%. RESULTS: Superficial defects were observed after the instrumentation of six root canals in the TF group and after the instrumentation of nine root canals in the R25 group. Plastic deformation and disruption of cutting edges were the prevalent defects observed in the TF group, and craters and blunt edges were observed in R25 files. The presence of defects was significantly increased with successive usages in both groups (P < 0.05), but TF had more superficial defects than R25 files (P < 0.001). Dentine debris was observed on all instruments. No instruments fractured. CONCLUSIONS: Instrumentation was possible for six root canals with TF files and nine root canals with R25 files before the presence of superficial defects appeared. Differences in the prevalence and development of superficial defects were observed between the TF and R25 files.

[Carcinoembryonic antigen in ascites and pleural effusions]. / Antigène carcino-embryonnaire dans les ascites et les épanchements pleuraux.

The purpose of this prospective study was to evaluate the usefulness of carcinoembryonic antigen (CEA) assays in effusion fluids for the diagnosis of cancer. From 1978 to 1981, 63 patients totaling 67 effusions were investigated for malignant cells and CEA concentrations. There were 62 cases of ascites and 5 cases of pleural effusion resulting from 35 cirrhoses and 28 cancers, including 17 adenocarcinomas. Macroscopic examination of serous membranes was possible in 24 patients. CEA concentrations at least 4 times higher than the upper limit of normal laboratory values were required to diagnose malignancy in effusions. The specificity of both cytology and CEA assays was 100 p. 100 in cirrhotic ascites. Malignant cells were present in 14 cases and positive CEA levels in 19 cases. CEA concentrations were highly significant (p less than 0.001) of cancerous effusions due to adenocarcinomas. In cancers other than adenocarcinoma and in hepatocarcinoma, CEA assays did not prove useful, and cytological examination remained the best diagnostic method. Both cytology and CEA levels were positive for malignancy in 11 effusions, and a diagnosis of cancer could be made on these grounds in 22 out 28 cases. Lack of correlation between CEA concentrations in sera and in effusion fluids suggests local production consecutive to invasion of the serous membranes. All 8 adenocarcinoma patients with grossly detectable extension to the peritoneum had high CEA concentrations, but malignant cells were absent in 4 cases. This discrepancy might tentatively be explained by local dissemination via the lymphatic system without disruption of the membrane but resulting in reflux of CEA into the effusion fluid.(ABSTRACT TRUNCATED AT 250 WORDS)

[Associated granular cell tumor and esophageal cancer (author's transl)]. / Association d'une tumeur à cellules granuleuses et d'un cancer de l'oesophage.

The first reported case of an association of Abrikossof's tumor and a cancer in the esophagus is described. After a general view of the published literature on these tumors, their clinical and pathological characteristics are outlined, and their histogenesis envisaged in relation to histochemical and ultrastructural findings. Therapeutic methods and means of follow-up surveillance are defined.

Spatial and temporal variation in Chaetanaphothrips orchidii Moulton (Thysanoptera: Thripidae) population and its damage on lemon.

Chaetanaphothrips orchidii Moulton has recently been detected in lemon (Citrus limon) orchards in northwest Argentina, causing high levels of damage on fruits. Severe damage results in the rejection of fruit for export, which must then be sold in the industry. However, the restrictions imposed by the citrus industry on insecticide residues sometimes also result in fruit rejection. Here, we studied the ecology and behavior of C. orchidii in order to propose a pest management strategy that could meet both export and industry demands. Seasonal occurrence and canopy distribution of C. orchidii in lemon orchards were evaluated, and field experimental manipulations of thrips populations were performed to analyze how the length (45, 100, 130, and 200 days) and timing (January, February, or March) of C. orchidii activity related with fruit damage. Lemons harvested during summer showed lower infestation levels (∼0.64 individual per fruit) than those harvested in winter (∼1.88 individuals per fruit). Higher proportions of damaged fruits were recorded in the lower part of the tree. Changes in the population levels of C. orchidii were closely associated with fruit phenology. The longer the lemon fruits were exposed to the thrips, the higher was the damage. However, the time of infestations did not affect fruit damage. Our data provide a first step towards understanding the factors that determine the severity of fruit damage caused by C. orchidii in northwest Argentina.

[Quality of water in the marine environment. The history and application of microbiology standards]. / Calidad del agua en el medio marino. Historia y aplicación de normas microbiológicas.

The history and application of microbiological standards to measure the quality of seawater for primary-contact recreational use and for the harvesting of shellfish are reviewed. Recent research concludes that enterococci, as indicator organisms, provide the most accurate correlation with gastrointestinal disorders attributed to swimming in contaminated waters. Accordingly, a linear relation has been established between mean enterococcus density per 100 ml and swimming associated gastrointestinal disorders per 1,000 population, and in 1984 the U.S. Environmental Protection Agency (EPA) adopted these bacteria as the primary indicator organisms for recreational waters in lieu of the indicators applied up til then, mainly total and fecal coliforms. International, national, and local microbiological standards and guidelines are presented to provide the sanitary engineer with a water quality range for the marine environment. Before adaptation of particular set of standards, local and national circumstances as well as socioeconomic factors should be carefully reviewed. Moreover, the application of quantitative relationships between health risks and the level of indicator organisms should take into account the general health and immunity conditions of the local population.

Health risks caused by freshwater cyanobacteria in recreational waters.

Toxic cyanobacteria are increasingly being perceived as a potential health hazard, particularly in waters used for recreation. A few countries are developing regulations to protect human health from these toxins, and the World Health Organization (WHO) has published both a guideline value for one cyanotoxin in drinking water and a procedural guideline for recreational waters. This article presents an overview of the currently known cyanotoxins and of documented cases of human illnesses attributed to them. It further discusses exposure pathways and approaches to risk management. In this context, the WHO guideline for recreational waters is presented, and monitoring approaches are outlined.

[Technical restatement about double contrast enema (author's transl)]. / Mise au point technique sur le lavement baryté en double contraste.

The prevention of the rectum and colon carcinoma consists principally in the radioendoscopic detection of colonic polyps. The double contrast enema is the best method for this detection. The usual practice of double contrast imposes the restatement of a comfortable method for the patient, simple and reliable for the doctor. The authors mean in this study to compare two groups of patients (group I and II) which differ by the double contrast technique used. If the colonic preparation, the injection implements and the investigation preliminaries are the same in both groups, there is no evacuation time of the barium enema which is added to trimebutine and stopped to the left iliac crest are specific with this method. The results allows an accuracy diagnosis of polyps.

[Giant scrotal lymphedema caused by Milroy's disease]. / Linfedema escrotal gigante por enfermedad de Milroy.

OBJECTIVES: To report a new case of giant scrotal lymphedema due to Milroy's disease, its treatment and outcome. METHODS: A 27-year-old man with generalized congenital lymphedema presented with a giant scrotal mass which interfered with his daily activities and physiological necessities. Physical examination showed a scrotal mass 40 x 40 cm in size and a normal penis. CT scan showed a homogeneous mass, thickened vaginal tunica, and bilateral hydrocele. RESULTS: A surgical procedure was performed including mass resection (5.6 kg), and bilateral hydrocelectomy. Skin defect was covered with skin grafts. CONCLUSIONS: Several therapeutic alternatives have been suggested for Milroy's disease with genital involvement. Nevertheless, when complications are as severe as in the present case, the only valid therapy is surgery.

Developing alternative approaches to urban wastewater disposal in Latin America and the Caribbean

The explosive rate of urbanization and industrialization in Latin America and the Caribbean has aggravated serious wastewater disposal problems. To address those problems, sound pollution control programs are needed - programs that are founded on a firm legal base and supported by an institutional infrastructure suitable for their effective operation. Such programs should make a point of employing technologies that are appropriate for the climatic and economic conditions prevailing in the areas they serve. Promising methods for dealing with such problems include use of submarine outfalls with minimal pretreatment for cities along coasts and estuaries, maximum use of receiving waters' assimilative capacity (as determined through application of system management and water quality models), reuse of treated sewage effluent for irrigation, and the application of unconventional technology for urban slum sanitation. This article reviews those various approches and describes the ongoing collaboration between national governments and PAHO's Pan American Center for Sanitary Engineering and Environmental Sciences (CEPIS) in the areas of research, information exchange, human resources development, and institutional development for the purpose of establishing a viable strategy and framework through which these major problems can be confronted and perhaps ultimately over come.(AU)