Minimum water activity requirements for the growth of Listeria monocytogenes

The ability of five strains of Listeria monocytogenes to initiate growth at five different temperatures in brain heart infusion (BHI) broth adjusted to various water activity ( a _w) values with either sodium chloride (NaCl), sucrose or glycerol was investigated. Glycerol was the least toxic of the three solutes studied, with three of five strains of L. monocytogenes capable of growing in BHI broth adjusted with glycerol to an a w value of 0.90 at 30 C, compared to a w minima of 0.93 and 0.92 in broth adjusted with sucrose and sodium chloride, respectively. The minimum a w value required for growth generally increased as the incubation temperature decreased. Listeria monocytogenes appeared to tolerate glycerol and NaCl best when growing at 30 and 15°C, respectively, while for sucrose, temperature did not appear to influence growth of the organism. Listeria monocytogenes is one of the few food-borne pathogens that can grow at an a w value below 0.93.     

Specificity of recognition of fragmented images in seven- to eight-year-old children: Analysis of event-related potentials

The topography and parameters of event-related potentials (ERPs) recorded during the presentation of incomplete images with different fragmentation were analyzed in seven- to eight-year-old children. The degree and mode of the involvement of different cortical zones at different stages of analysis and processing of fragmented images were determined. It was found in children that the prefrontal cortical areas were involved in the recognition of incomplete images in the same way as in adults. Age-related differences manifested themselves in a lower intensity of the slow positive complex in children, reflecting the decision-making and information retention processes required for the preparation of an answer.     

Age-related specificity of the processing of visual information in the system of working memory

In adults and seven- to eight-year-old children, event-related potentials (ERPs) were analyzed during quiet observation and detailed paired comparison of visual stimuli. In both age groups, we showed the differences in the initial stages (component N1) of sensory analysis in these situations. In adults, an increase in the negativity during the initial stages of analysis was observed in the caudal and central areas of the cortex during presentation of standard and test stimuli. In the frontal areas of the cortex, an increase in the negative potential was observed only in ERPs induced by the test stimulus. In children, an increase in the negativity at the initial phases of analysis of stimuli in the situation of working memory, as compared to quiet observation, was confined to the caudal areas of the cortex. Differential curves that characterize analysis of standard and test stimuli showed age-related differences in the initial and late phases of information processing under the conditions of working memory. In adults, the differential curves that characterize analysis of the standard stimulus were represented by negative phases, and the curves related to the test stimulus, by positive phases. In children, late phases of analysis of the standard and test stimuli had smaller differences as compared to adults: the late positive wave was predominant in the responses to both standard and test stimulus in the caudal areas of the cortex. In the frontal areas, there was no considerable increase in the amplitude of the late positive wave in response to the test stimulus. This fact, together with the absence of enhancement of initial negativity in the frontal areas, which reflects analysis of the test stimulus, indicates that the prefrontal cortex plays a smaller role in the comparison of the memory trace with the current information in seven- to eight-year-old children. The data obtained suggest that the central executive of working memory is not sufficiently mature in children aged seven to eight years.     

DERMATOLOGIC CHANGES IN THE CIRCUMILEOSTOMY SKIN

A comprehensive questionnaire inquiring about difficulties with care of the skin in the area immediately surrounding the artificial anus was sent to ileostomy patients in the United States. Eighty per cent of 327 replying to the questionnaire had such difficulties.The problem of irritation is essentially that of intimate contact of fecal material with the circumileostomy skin, and associated factors are the potentially irritating materials used in the manufacture of ileostomy appliances, as well as the adhesives used to affix the appliance to the skin. Mechanical trauma incident to removal and reapplication of the appliance, as well as loosening of the disc and exposure of unprotected skin, accelerates the corrosive action of the material discharged. Changing the appliance before leakage or irritation occurs is helpful in preventing skin difficulties.In cases of long standing or repeated irritation, care must be taken to check the suitability of the appliance or the possibility of a complication in the stoma that could be corrected surgically.     

INTERMITTENT POSITIVE PRESSURE BREATHING—A Clinical Evaluation of Its Use in Certain Respiratory Diseases

A series of patients with chronic respiratory insufficiency were treated with intermittent positive pressure breathing, which was combined with administration of bronchodilator drugs of the epinephrine series. Spirographs were made before and after treatment. The series included patients with chronic bronchitis and emphysema, fibrosis of various kinds, senile emphysema and bronchogenic carcinoma.Although the majority showed objective improvement, a significant proportion in all groups did not, and some were made worse, apparently on a basis of check valve mechanisms unresolved by the bronchodilator drug. In cases in which the method benefited the patient, the benefit was greater than that obtained with bronchodilator drugs alone.