[Environmental health: concepts and activities]. / Salud ambiental: conceptos y actividades.

The objective of this study is to provide information and a conceptual framework that will facilitate the work of persons in charge of systematizing institutions devoted to environmental health. The notion of "environment" is examined and a definition is proposed, while a look is also taken at the place held by environmental health within the context of environmental problems and their "green" and "blue" components. A number of definitions are put forth before presenting the official definition of environmental health issued by WHO in Sofia (1993). Subsequently a list is presented of the basic areas that have been assigned to the field of environmental health by different organizations or at various meetings, with PAHO, WHO, and Program 21 among them. From this a rather exhaustive list of areas and subareas is constructed, with the finding that all lists are, in reality, an asystematic grouping of three different components: determining factors (from the physical world), processes (types of interventions), and roles (series of administrative tasks) which can be conceived as a matrix and which allow for the description of individual activities by the environmental health services. Certain rules of operation are proposed which make it possible, through a form of algebra, to construct expressions for describing such activities and their aggregates with some precision. Thus, it becomes possible to employ a common symbolic language which can facilitate intercommunication, teaching, and research in the area of environmental health.

Preventable factors in hospital admissions for asthma.

Asthma remains the second most common cause for admissions to a paediatric hospital bed. The aim of this study was to describe the characteristics of children admitted to hospital with an acute asthma attack and to identify factors that may prevent future hospital admissions. Parents of all children aged 3 to 15 years admitted to hospital for acute asthma were interviewed and the child's case record reviewed. Children were recruited consecutively in two groups: 141 summer/autumn and 125 winter/spring 1996. According to the pattern of symptoms in the previous 12 months, 61% of the children had infrequent episodic asthma, 26% had frequent episodic asthma, and 13% persistent asthma. Only 8% of children aged 8 years or less had persistent asthma, in contrast to 22% of those aged > 8 years. There was evidence of both inadequate prescription of preventive treatment and poor compliance in the frequent episodic and persistent asthma groups. Of the whole group, 44% had previously been given an acute asthma management plan, but only 9% of them used it before the current hospital admission. There was a delay in seeking medical advice (> 24 hours after the onset of symptoms) in 27% of all admissions. This study has identified potential areas where intervention may reduce the number of future admissions.

Lymphocyte phenotyping by fluorescence microscopy and flow cytometry: results in homosexual men and heterosexual controls.

Absolute numbers of peripheral blood T3, T4 and T8 positive cells from 15 homosexual men and concurrent controls were determined by fluorescence microscopy (FM) and by a fluorescence-activated cell sorter (FACS). A significant difference in the number of positive cells was observed between FM and FACS in the control group for all three monoclonal antibodies and for the T4/T8 ratio. FACS methodology yielded a lower number of T4 positive cells and a lower T4/T8 ratio in the homosexual subjects. Two homosexual men had normal T4/T8 ratios by FM but were found to have low ratios by FACS. The reasons for the disparate results obtained by the two methods are unclear, but such findings are important to bear in mind when evaluating male homosexuals for immunologic abnormalities.

Serological diagnosis of Toxoplasma gondii infections by rapid separation of serum immunoglobulins M and G with CM Bio-Gel A.

A simple and rapid method has been developed for the separation of serum immunoglobulin M (IgM) and IgG. CM Bio-Gel A chromatography was used in the technique, which resulted in an IgM-rich fraction containing 31% of the original serum IgM and less than 2% of the serum IgG. The procedure was used to detect masked IgM antibodies in patients suspected of having Toxoplasma gondii infections.

The use of pluronic polyols in the precipitation of plasma proteins and its application in the preparation of plasma derivatives.

Pluronic F-38 was used a precipitant of plasma proteins under varying conditions of pH and polymer concentration. Results indicated that marked differences in the solubility of the plasma proteins in F-38 solutions can be appled to the separation of plasma components. The feasibility of the industrial application of this fractionation method was tested in several experiments. Conditions were established for the preparation of albumin, human plasma protein fraction (HPPF), and immune serum globulin (ISG) with similar yield and purity as those prepared by the Cohn methods. Current procedures for the preparation of antihemophilic A (Facor VIII) concentrate and prothrombin complex (Factors II, VII, IX, and X) were adapted to the F-38 process by removal of the clotting factors from the starting plasma prior to polymer precipitation. In addition, a plasma protein solution free of lipoproteins, isoagglutinins, and clotting factors was developed which has proven useful as a perfusion medium in organ preservation.