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.     

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.     

Apparent decline in the harbour seal Phoca vitulina population near Hvaler, Norway, following an epizootic

From 1986-90 we tagged 98 harbour seal pups at Hvaler, Norway Fifteen were recovered later the same year of which 10 were recovered in 1988, when the seal population was infected by a morbillivirus The epizootic in 1988 resulted in a population decline of c 75% Predicted birth weight did not vary significantly before and after the epizootic Newborn harbour seals have antibodies against the morbillivirus two years after the outbreak of the disease     

Sequence divergence in the ORF6 gene of Mycoplasma pneumonia.

The ORF6 gene product of Mycoplasma pneumoniae is involved in a yet-unknown manner in the adhesion of the bacterium to its host cell. Part of the ORF6 gene is a repetitive DNA sequence (RepMP5), about 1,900 bp long. Seven additional similar copies of RepMP5 are dispersed on the genome. In the independently isolated strains M. pneumoniae M129 and FH, the RepMP5 copies residing in the ORF6 gene are not identical. Two conserved regions, ranging from nucleotides 1 to 799 and from nucleotide 1795 to the end of the gene, border a variable region, ranging from nucleotides 800 to 1794. This variable region differs in DNA sequence and by 201 bp. Analysis of RepMP5 copies outside the ORF6 gene showed that both M. pneumoniae M129 and M. pneumoniae FH carry a RepMP5 copy on a 6-kbp EcoRI fragment which has the same DNA sequence as the variable region of RepMP5 in the M. pneumoniae FH ORF6 gene. According to these data, a switch from the M. pneumoniae M129 ORF6 gene to the M. pneumoniae FH ORF6 gene could take place by gene conversion.     

Physiology, thermoregulation and bipedalism

It has long been recognized that the bipedal posture reduces the surface area of the body exposed to the sun. In recent years, a theory has been developed by Wheeler that bipedalism evolved in the ancestor of the Hominidae in order to help relieve thermal stress on the animals in open equatorial environments. Bipedalism was said to afford a distinct adaptive advantage over quadrupedalism by permitting hominids to remain active in the open throughout the day. The heat load of the hypothetical hominid comprises the external environment as modelled by Wheeler and the animal's internal environment (i.e., the internal heat generated by its metabolic and locomotor activities, and its evaporative and respirative cooling capacities). When these factors are integrated in the calculation of the animal's thermal budget, the putative advantage of the bipedal over the quadrupedal posture is considerably reduced. The simulations conducted in this study suggest that the increased time afforded to early hominids in the open by bipedalism was relatively short and, therefore, of little or no adaptive significance. These results suggest that thermoregulatory considerations cannot be implicated as a first cause in the evolution of bipedalism in the hominid ancestor.     

Effect of nitrogen supply on frost resistance, nitrogen metabolism and carbohydrate content in white clover (Trifolium repens)

Effects of mineral nitrogen (2, 4, 6 and 8 m M NH₄NO₃) and nodulation with Rhizobium on frost hardiness in seedlings of white clover ( Trifolium repens ) have been studied. Seedlings of a population from Bodø (67°N lat.) were grown in Leonard jars under controlled conditions in a phytotron. For induction of frost hardening, plants were first exposed to 12 h photoperiod conditions for 2 weeks at 18°C, then for 2 weeks at 6°C and finally for 2 weeks at 0.5°C. Frost hardiness after treatments at 6 and 0.5°C was significantly enhanced by increasing nitrogen supply and was positively correlated with total nitrogen content of the stolons. Frost hardiness of nodulated plants correlated to the tissue nitrogen concentration. Content of soluble proteins in stolons decreased during hardening at 6°C but did not change during treatment at 0.5°C. There were minor changes in total amount of free amino acids during hardening. Both absolute and relative amounts of proline and arginine increased, and those of asparagine decreased during hardening. Absolute amounts of all free amino acids increased with increasing nitrogen supply, but the changes during hardening were similar in all treatments. There was a significant increase in the content of soluble carbohydrates during hardening. However, this increase was inversely related to nitrogen supply.     

The influence of encapsulation upon the ability of Klebsiella pneumoniae to survive whilst airborne and to cause lung disease in mice

Cultures of a strain of Klebsiella pneumoniae were prepared, both with intact capsules and with only a residual layer of exopolysaccharide remaining. No significant difference in the survival of the two sets of bacteria was observed in aerosols at 60% relative humidity. The decapsulated bacteria multiplied less rapidly in mouse lungs than did the intact bacteria for the first 24 h after animal exposure. However, no subsequent difference in multiplication rate was observed.