Biological and behavioral markers of pain following nerve injury in humans.

The evolution of peripheral and central changes following a peripheral nerve injury imply the onset of afferent signals that affect the brain. Changes to inflammatory processes may contribute to peripheral and central alterations such as altered psychological state and are not well characterized in humans. We focused on four elements that change peripheral and central nervous systems following ankle injury in 24 adolescent patients and 12 age-sex matched controls. Findings include (a) Changes in tibial, fibular, and sciatic nerve divisions consistent with neurodegeneration; (b) Changes within the primary motor and somatosensory areas as well as higher order brain regions implicated in pain processing; (c) Increased expression of fear of pain and pain reporting; and (d) Significant changes in cytokine profiles relating to neuroinflammatory signaling pathways. Findings address how changes resulting from peripheral nerve injury may develop into chronic neuropathic pain through changes in the peripheral and central nervous system.

Polyhydroxyalkanoate degradation is associated with nucleotide accumulation and enhances stress resistance and survival of Pseudomonas oleovorans in natural water microcosms.

Pseudomonas oleovorans GPo1 and its polyhydroxyalkanoic acid (PHA) depolymerization-minus mutant, GPo500 phaZ, residing in natural water microcosms, were utilized to asses the effect of PHA availability on survival and resistance to stress agents. The wild-type strain showed increased survival compared to the PHA depolymerase-minus strain. The appearance of a round cellular shape, characteristic of bacteria growing under starvation conditions, was delayed in the wild type in comparison to the mutant strain. Percent survival at the end of ethanol and heat challenges was always higher in GPo1 than in GPo500. Based on these results and on early experiments (H. Hippe, Arch. Mikrobiol. 56:248-277, 1967) that suggested an association of PHA utilization with respiration and oxidative phosphorylation, we investigated the association between PHA degradation and nucleotide accumulation. ATP and guanosine tetraphosphate (ppGpp) production was analyzed under culture conditions leading to PHA depolymerization. A rise in the ATP and ppGpp levels appeared concomitant with PHA degradation, while this phenomenon was not observed in the mutant strain unable to degrade the polymer. Complementation of the phaZ mutation restored the wild-type phenotype.

Polyhydroxyalkanoates degradation affects survival of Pseudomonas oleovorans in river water microcosms

Bacterial survival in natural environments involves the ability of scavenging nutrients and energy sources. Polyhydroxyalkanoates (PHAs) are intracellular polymers that endow bacteria with enhanced survival capabilities in adverse environmental conditions. In this paper we compared survival of Pseudomonas oleovorans wild type and PHA depolymerase mutant strains in natural river waters by using microcosms. Experiments were performed with water samples collected from the Rio de la Plata. The survival of the P. oleovorans strain capable of degrading PHA was higher in raw river water compared to the depolymerase negative mutant strain. Bacterial numbers decreased during the experiment. At the end of the experiment, the difference in the number of cells between wild type and mutant strains was of 3 orders of magnitude. Mutants deficient in PHA degradation are useful to study the importance of reserve polymers in the survival of bacterial species in natural environments. They could also provide an adequate system for the analysis of the role of PHA in the tolerance to physical or chemical stress agents.

Polyhydroxyalkanoates degradation affects survival of Pseudomonas oleovorans in river water microcosms

Bacterial survival in natural environments involves the ability of scavenging nutrients and energy sources. Polyhydroxyalkanoates (PHAs) are intracellular polymers that endow bacteria with enhanced survival capabilities in adverse environmental conditions. In this paper we compared survival of Pseudomonas oleovorans wild type and PHA depolymerase mutant strains in natural river waters by using microcosms. Experiments were performed with water samples collected from the Rio de la Plata. The survival of the P. oleovorans strain capable of degrading PHA was higher in raw river water compared to the depolymerase negative mutant strain. Bacterial numbers decreased during the experiment. At the end of the experiment, the difference in the number of cells between wild type and mutant strains was of 3 orders of magnitude. Mutants deficient in PHA degradation are useful to study the importance of reserve polymers in the survival of bacterial species in natural environments. They could also provide an adequate system for the analysis of the role of PHA in the tolerance to physical or chemical stress agents.(AU)

Evaluation of Xanthomonas campestris survival in a soil microcosm system.

Xanthomonas campestris pv. campestris is a pathogen of cruciferous plants. We studied the survival of the wild type strain and mutant derivatives which are deficient in exopolysaccharide (EPS) or in extracellular protease synthesis in soil microcosms in order to test the hypothesis that, in this environment, adherence to soil particles and scavenging of nutrients are very important strategies for bacterial survival. In sterile soil microcosms, differences in survival were only observed between the EPS producer and its mutant. In non-sterile soil experiments, survival of Prt- mutant was similar to EPS- mutant, suggesting that both characteristics have a strong influence in survival in the presence of the natural bacterial community. Bacterial decrease represented by the slope of regression lines was higher in non-sterile soil microcosms due to the influence of biotic interactions.

Polyhydroxyalkanoates degradation affects survival of Pseudomonas oleovorans in river water microcosms.

Bacterial survival in natural environments involves the ability of scavenging nutrients and energy sources. Polyhydroxyalkanoates (PHAs) are intracellular polymers that endow bacteria with enhanced survival capabilities in adverse environmental conditions. In this paper we compared survival of Pseudomonas oleovorans wild type and PHA depolymerase mutant strains in natural river waters by using microcosms. Experiments were performed with water samples collected from the Rio de la Plata. The survival of the P. oleovorans strain capable of degrading PHA was higher in raw river water compared to the depolymerase negative mutant strain. Bacterial numbers decreased during the experiment. At the end of the experiment, the difference in the number of cells between wild type and mutant strains was of 3 orders of magnitude. Mutants deficient in PHA degradation are useful to study the importance of reserve polymers in the survival of bacterial species in natural environments. They could also provide an adequate system for the analysis of the role of PHA in the tolerance to physical or chemical stress agents.

Use of sulfite resistance in Saccharomyces cerevisiae as a dominant selectable marker.

Two S. cerevisiae genes were found to exhibit dominant phenotypes useful for selecting transformants of industrial and laboratory strains of S. cerevisiae. FZF1-4, which confers sulfite resistance, was originally isolated and identified as RSU1-4, but the two genes are shown here to be allelic. Cysteine 57 in wild-type Fzf1p was found to be replaced by tyrosine in Fzf1-4p. Multicopy SSU1, which also confers sulfite resistance, was found to be somewhat less efficient. In both cases, a period of outgrowth in non-selective medium following transformation was found to be necessary. The number of transformants obtained was found to be strain-dependent, and also to depend on the sulfite concentration used during selection. Undesirable background growth of non-transformants was not observed at cell densities as high as 2.5 x 10(7)/plate. In two ura3 laboratory strains where selection for URA3 was applied independently of that for sulfite, the transformation efficiency for sulfite resistance was about 50% that for uracil prototrophy.

Monitoring by PCR amplification of the polyphosphate kinase gene added to natural water samples.

A fast, simple method for the detection of the Escherichia coli polyphosphate kinase (ppk) gene by means of PCR amplification is described. The method uses filters to recover cells from the samples, which makes it suitable for environmental studies. The detection of the ppk gene was achieved from samples containing 10(2) E. coli cells, either in saline solution or in river water.

Potential impact of linking an emergency department and hospital-affiliated clinics to immunize pre-school-age children.

OBJECTIVE: To determine whether the use of an urban pediatric emergency department (ED) to immunize pre-school-age children would result in an improvement in the percentage fully vaccinated by the end of the second year of life. DESIGN: A retrospective cohort study of two groups: (1) 100 consecutive children (ED group) enrolled at one of two hospital-affiliated primary care clinics were chosen from the ED patient logs if their second birthday occurred in the 12 months prior to November 1990; and (2) 91 age-matched control children (control group) were chosen at random from the same hospital-affiliated clinics' enrollment logs without regard to ED use. The health care provided during the first 2 years of life for each group was compared. RESULTS: The mean number of visits to the ED in the first 2 years of life by the ED group was significantly greater than that of the control group (2.9 [SD] +/- 2.5 vs 1.1 +/- 1.4; P < .001) during the first 2 years of life. In 67% of ED visits, children would have been well enough to receive a vaccination. Both groups had similar types and numbers of visits to the primary clinics. For example, the ED group had 10 +/- 5 visits by age 2 years compared with the control group, which had 9 +/- 4 visits. There was no significant difference in actual immunization percentages achieved in the clinic, with 62% of the ED group having received four diphtheria, pertussis, and tetanus vaccinations; three oral poliovirus vaccinations; and one measles, mumps, and rubella vaccination by age 2 compared with 69% of control children. There were more missed vaccination opportunities during clinic visits in the ED group (7.4 vs 4.6 per 100 clinic visits; P < .01). If immunizations were offered in the ED to those children who needed them, immunization percentages would have been increased an average of 20% compared with percentages achieved in the clinic alone. CONCLUSION: Routine vaccinations in the ED would significantly increase immunization percentages in children enrolled in two hospital-affiliated clinics. Close linkage and coordination between the ED and hospital-affiliated clinics may improve preventive health care in urban children who use EDs.