Virulence-associated characteristics and phage lysogenicity of two morphologically distinct colonies of Vibrio cholerae O139 serogroup

Abstract The presence of a temperate phage was demonstrated in a strain of Vibrio cholerae O139 isolated from a patient. Spontaneous variants with translucent colonies had lost this phage. The loss of the phage was associated with increased hydrophobicity, indicating the loss of the capsule. These clones were sensitive to serum bactericidal activity, showed decreased expression of such presumed virulence factors as proteases, motility and mannose-sensitive pili. Furthermore, excision of the phage made the strain dependent on purines for growth.     

Assessing the promise of user involvement in health service development: ethnographic study

Objectives To understand how the policy of user involvement is interpreted in health service organisations and to identify factors that influence how user involvement is put into practice.Design Ethnographic study using participant observation, interviews, and collection of documentary evidence.Setting A multiagency modernisation programme to improve stroke services in two London boroughs.Participants Service users, National Health Service managers, and clinicians.Results User involvement in the programme was initiated and led by professionals. Professionals determined the areas of service improvement service users could participate in. A wide range of activities were considered “user involvement,” from patient satisfaction surveys to service users delivering peer support. Involvement tended to be most active in the least technical areas and areas with least input from clinicians. Factors that might explain this included organisational structure, the vagueness of the concept of user involvement, the value attributed to service users’ experiential knowledge, and variations in professional and service user understandings of and commitment to involvement. The gains of involvement were harder to identify in terms of impact on services. More evident were the personal gains for those involved: satisfaction of feeling listened to by professionals, social opportunities of meeting others in a similar situation, and increased knowledge about stroke and services available.Conclusions User involvement may not automatically lead to improved service quality. Healthcare professionals and service users understand and practise user involvement in different ways according to individual ideologies, circumstances, and needs. Given the resource implications of undertaking user involvement in service development there is a need for critical debate on the purpose of such involvement as well as better evidence of the benefits claimed for it.     

Kinetics of Ca+ adsorption and cationic selectivity with a synaptic membrane protein

A study was conducted on the adsorption of ⁴⁵Ca²⁺ to a surface film of a hydrophobic protein derived from synaptic membranes isolated from bovine cerebellum. A kinetic analysis of Ca²⁺ displacement from the protein by various metal and organic cations could be described by a rate law based on diffusion and displacement. The relative rate constants for the displacement of bound Ca²⁺ were in the order Li⁺ <Na⁺, Rb⁺ <Cs⁺ <K⁺, NH₄⁺. Among the alkaline earth series the sequence was Mg²⁺, Sr²⁺ <Ba²⁺. Ca²⁺ adsorption could be described by a theoretical formulation which takes into account an interfacial energy and potential barrier as well as the diffusional process. An attempt was made to consider the effect of energy of hydration of the cations, surface charge, and the chemical environment at the interface on catonic selectivity. The behavior of the cations in this system significantly resemble their behavior in natural membranes, particularly excitatory ones. The structural and physicochemical environment of the protein at the interface is discussed in relation to Ca²⁺ binding and cationic selectivity.     

The use of agarose bead culture for the regeneration of single cell-derived colonies from protoplasts isolated from suspension cultures of Humulus lupulus

A cell-wall digestion medium has been devised to isolate protoplasts from suspension cultures of Humulus lupulus. Conditions have been developed for colony formation from protoplasts and the plating efficiency determined in three types of agar and by two culture methods. Viable calli were produced only when protoplasts embedded in Seaplaque agarose were incubated in a defined liquid medium. HPLC analysis showed that none of the isolated colonies accumulated -acids.     

Autologous antibodies to human bladder cancer

Summary The autologous serologic reactivity of 13 patients with bladder cancer was evaluated using cell lines derived from each individual's own tumor as targets. Protein A and immune adherence assays were employed to determine antibody binding to the tumor targets at varying passage numbers. Autologous reactivity was found in 6 of the 13 cell lines tested. However, the titer was usually low regardless of the passage number. Seven autologous serum/cell line combinations were tested using both low and high passage cells as targets. In six of these combinations, the degree of antibody binding was similar with both low and high passage target cells. The incidence of autologous reactivity in the 12 patients with urothelial tumors was 50%.This investigation was supported by PHS Grant number CA36933, awarded by the National Cancer Institute, DHHS.     

Copper absorption in young men fed adequate and low zinc diets

Copper absorption was measured at two levels of dietary zinc in six healthy young men who were confined to a metabolic unit for a 75 d study of zinc utilization. A diet of conventional foods was fed, providing either 16.5 or 5.5 mg zinc and 1.3 mg copper daily. Copper absorption was determined by feeding⁶⁵Cu, a stable isotope of copper, once during the 16.5 mg Zn diet and near the beginning and end of the 5.5 mg Zn diet. Apparent copper absorption averaged 48.1% when the 16.5 mg Zn diet was fed. This was significantly higher than the averages of 37.2 and 38.5% when the 5.5 mg Zn diet was fed. Absorption also differed significantly among subjects. Fecal copper did not differ between diets or among subjects. All subjects were in positive copper balance at both levels of dietary zinc. These results suggest that a dietary zinc intake slightly above the Recommended Dietary Allowance of 15 mg/d does not increase fecal copper loss and does not interfere with copper absorption.     

Chromium in plants

Chromium is an essential trace element and is associated with some biological pathways, especially with glucose tolerance. For these reasons, we decided to determine the concentration of chromium in two sets of Brazilian medicinal plants. The first group consisted of plants that are considered as antidiabetic, whereas the second included plants that do not have this therapeutic property. The concentration of chromium was determined by flameless atomic absorption. All the plants analyzed contain chromium in the normal range for this element, but the hypoglycemic plants contain more chromium than the others (1–4 μg/g compared to 0.5–1.5 μg/g).     

Comparison of the seed germination effects of synthetic analogs of strigol,gibberellic acid,cytokinins, and other plant growth regulators

Four synthetic multiring analogs of strigol, a naturally occurring sesquiterpene lactone that promotes germination of dormant seeds ofStriga (witchweed), were found to stimulate germination of dormantLactuca (lettuce) seeds. The effects on light-sensitive and light-insensitive lettuce seeds were concentration-dependent and exceeded those produced by equimolar (0.1 mM) solutions of gibberellic acid. Strigol and epistrigol promoted lettuce seed germination to a lesser degree than did the synthetic analogs. The strigol group compounds had minimal effect on the germination of monocot seeds. The results indicate that the synthetic strigol analogs have plant growth regulatory activity in dormant seeds of genera beyondStriga in which germination stimulation by strigol and the synthetic analogs was first demonstrated.Names of companies of commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.     

Sorbitol Gum in Xerostomics: The Effects on Dental Plaque pH and Salivary Flow Rates1

Adequate salivary flow is important for patient comfort and maintenance of oral health. Xerostomia, or dry mouth, is a common clinical complaint. Masticatory and gustatory activity can stimulate salivary flow from functional salivary tissue and the use of sugarless mints and gums have been recommended to individuals who complain of xerostomia, but there are minimum clinical data. A clinical study assessing the effect on salivary flow rates and dental plaque pH of a sorbitol-sweetened chewing gum in subjects with the complaint of xerostomia was conducted. The chewing of the gum in this present study stimulated salivary flow in the subjects with xerostomia. Statistically significant stimulated whole mouth and parotid salivary flow rate increases were found when compared to unstimulated whole mouth and parotid salivary flow rates. Chewing of the sorbitol-sweetened gum also effectively reduced the drop in pH seen following the exposure to a fermentable carbohydrate. The findings of this present study indicate that chewing of a sorbitol-sweetened gum may be of benefit to patients with the complaint of xerostomia.