Empirical trials of plant field guides.

We designed 3 image-based field guides to tropical forest plant species in Ghana, Grenada, and Cameroon and tested them with 1095 local residents and 20 botanists in the United Kingdom. We compared users' identification accuracy with different image formats, including drawings, specimen photos, living plant photos, and paintings. We compared users' accuracy with the guides to their accuracy with only their prior knowledge of the flora. We asked respondents to score each format for usability, beauty, and how much they would pay for it. Prior knowledge of plant names was generally low (<22%). With a few exceptions, identification accuracy did not differ significantly among image formats. In Cameroon, users identifying sterile Cola species achieved 46-56% accuracy across formats; identification was most accurate with living plant photos. Botanists in the United Kingdom accurately identified 82-93% of the same Cameroonian species; identification was most accurate with specimens. In Grenada, users accurately identified 74-82% of plants; drawings yielded significantly less accurate identifications than paintings and photos of living plants. In Ghana, users accurately identified 85% of plants. Digital color photos of living plants ranked high for beauty, usability, and what users would pay. Black and white drawings ranked low. Our results show the potential and limitations of the use of field guides and nonspecialists to identify plants, for example, in conservation applications. We recommend authors of plant field guides use the cheapest or easiest illustration format because image type had limited bearing on accuracy; match the type of illustration to the most likely use of the guide for slight improvements in accuracy; avoid black and white formats unless the audience is experienced at interpreting illustrations or keeping costs low is imperative; discourage false-positive identifications, which were common; and encourage users to ask an expert or use a herbarium for groups that are difficult to identify.

Endothelial-dependent vasodilation is associated with increases in the phosphorylation of a small heat shock protein (HSP20).

PURPOSE: Increases in the phosphorylation of a small heat shock protein (HSP20) are associated with cyclic nucleotide-dependent vasorelaxation. The effect of pressure and flow on vessel diameter was studied. We hypothesized that physiologic conditions that induce vasorelaxation would lead to increases in HSP20 phosphorylation. METHODS: Flow-dependent changes in vessel diameter, at different intraluminal pressures, were measured with a laser optical micrometer in intact bovine carotid arteries. Experiments were performed in the presence and absence of norepinephrine (10(-5) mol/L). Increases in the phosphorylation of HSP20 were determined with isoelectric focusing immunoblots. RESULTS: The increase in vessel diameter was most significant at low intraluminal pressures (20 mm Hg), high flow rates (200 mL/min), and in the presence of the vasoconstrictor norepinephrine (10(-5) mol/L). The addition of methylene blue (a guanylate cyclase inhibitor) completely inhibited flow-induced vasodilation. Under conditions in which maximal flow induced vasodilation occurred, there were significant increases in the phosphorylation of HSP20. CONCLUSION: Flow-dependent vasodilation in isolated perfused segments of bovine carotid arteries was maximal when the intraluminal pressures were low and when the vessels were precontracted with norepinephrine. Flow-dependent vasodilation was inhibited by methylene blue and was associated with increases in the phosphorylation of HSP20, suggesting that the vasodilation was mediated by endothelial production of nitric oxide.

Peroxisomes and peroxisomal enzymes in the human fetal small intestine.

The appearance and development of peroxisomes and the expression of their enzymes in the human fetal intestine have been investigated between 11 and 22 weeks of gestation. In the youngest samples (11-16 weeks of age), cytochemistry at the ultrastructural level revealed the presence of rare, mostly circular peroxisomes. From 16 weeks of gestation onwards, an increase was noted in the number of peroxisomes. Two peroxisomal types were distinguished: round to oval forms and elongated and/or tailed organelles. Biochemical assays revealed that total and specific intestinal catalase activities increased gradually between 11 and 20 weeks of gestation. The activity of fatty acylCoA oxidase, the first enzyme of the peroxisomal beta-oxidation system, was detectable as early as 11 weeks of gestation. Thereafter, total and specific activities of the enzyme increased steadily. Activities of other peroxisomal oxidases (D-amino acid oxidase, L-alpha-hydroxyacid oxidase) appeared more slowly in the fetal intestine during the period studied. This investigation establishes the presence and the morphological changes that occur in intestinal peroxisomes during human fetal development as well as the developmental patterns of associated enzymes.

Minor injuries clinics: dealing with trauma.

This article examines the emerging development of nurse-led minor injuries units. It considers the impact of this on doctor-nurse relationships and the factors that need to be assessed and planned when initiating such a service.

Studies on peroxisomes of colonic mucosa in Crohn's disease.

The etiology and pathogenesis of Crohn's disease, a chronic inflammatory bowel pathology, have not been elucidated yet. In particular, the behavior of peroxisomes in inflamed colonic mucosa has not been investigated despite their important role in cellular oxidative metabolism. Using cytochemistry at the ultrastructural level, we have observed these catalase-positive organelles. In addition, biochemical analyses have revealed the specific activities of catalase and cyanide-insensitive acyl-CoA oxidase. Mucosal biopsy specimens from inflamed and noninflamed areas of Crohn's patients were compared to control biopsies. We found that Crohn's disease was marked by an important diminution in the peroxisomal frequency per cell unit area. If catalase activity was not affected by this pathology, cyanide-insensitive acyl-CoA oxidase, an enzyme of the peroxisomal beta-oxidation system, was found diminished in inflamed and in noninflamed areas. In conclusion, our results showed that Crohn's disease is accompanied by peroxisomal modifications but the number and the enzyme activities of colonic peroxisomes are less deeply altered in Crohn's disease than during neoplasia. This fact suggests that a relation may exist between the degree of peroxisomal deficiency and the clinical severity of colonic disease.

Peroxisomes and peroxisomal enzymes along the crypt-villus axis of the rat intestine.

The development of peroxisomes and expression of their enzymes were investigated in differentiating intestinal epithelial cells during their migration along the crypt-villus axis. Sequential cell populations harvested by a low-temperature method were identified by microscopy, determination of alkaline phosphatase and sucrase activities and incorporation of [3H]-thymidine into DNA. Ultrastructural cytochemistry after staining for catalase activity, revealed the presence of peroxisomes in undifferentiated stem cells located in the crypt region. Morphometry indicated that the number of these organelles increased as intestinal epithelial cells differentiate. Catalase activity was higher in the crypt cells than in the mature enterocytes harvested from villus tips. On the other hand, an increasing gradient of activity was observed from crypts to villus tips for peroxisomal oxidases, i.e. fatty acyl coA oxidase, D-amino acid oxidase and polyamine oxidase. These findings indicate that biogenesis of peroxisomes occurs during migration of intestinal epithelial cells along the crypt-villus axis and that peroxisomal oxidases contribute substantially to the biochemical maturation of enterocytes.

Peroxisome through cell differentiation and neoplasia.

Peroxisomes are essential in cellular metabolism as their dysgenesis or defects in single enzymes or impairment of multiple peroxisomal enzymatic functions have been found in several inherited metabolic diseases with serious clinical sequelae. The assembly and formation of these cytoplasmic organelles constitute a major and intriguing research topic. In the present study the biogenesis of peroxisomes and the developmental patterns of their enzymes have been reviewed during embryonic and/or post-embryonic ontogenesis of lower (amphibians) and higher (avians, mammals) vertebrates. In developing vertebrates, epithelial cell differentiation is accompanied by increases in frequency and size of peroxisomes. The tissue-specific expression of peroxisomal enzymes contributes substantially to the biochemical maturation of epithelial cells. The relationship between biogenesis of peroxisomes, expression of peroxisomal enzymes and structural and functional cellular phenotype has also been investigated in differentiating epithelial cells along the crypt-villus axis of the adult rat intestine. Cytochemical studies at the ultrastructural level have provided evidence that peroxisomes are already present in proliferating cells of the intestinal crypt region before they begin to differentiate. Migration and differentiation of intestinal epithelial cells from crypt to villus compartments are marked by significant increases in number and size of catalase-positive structures. Increasing activity gradients from crypt to surface areas are found for the peroxisomal oxidases examined (enzymes of the peroxisomal beta-oxidation system, D-amino acid oxidase and polyamine oxidase). Thus, peroxisomes are more and more involved in oxidative metabolic pathways as intestinal epithelial cells differentiate. Finally, we have analyzed the peroxisomal behaviour in human neoplastic epithelial cells. The presence of peroxisomes has been cytochemically revealed in human breast and colon carcinomas. Peroxisomal enzyme specific activities are significantly lower in human breast and colon carcinomas than in the adjacent healthy mucosa. Furthermore, a relationship is found between the specific activities of some peroxisomal enzymes and the histological tumour grades.

Peroxisomes in human colon carcinomas. A cytochemical and biochemical study.

The presence of peroxisomes and their enzymic content were investigated and compared in healthy and neoplastic human colon epithelial cells using cytochemical studies at the ultrastructural level as well as biochemical analyses. Catalase-positive organelles were found to be more numerous in normal than in colonic neoplastic cells. Biochemical assays revealed that no D-aminoacid oxidase or L-alpha-hydroxyacid oxidase activity was detected in normal or tumor tissues. The specific activities of catalase, fatty-acyl CoA oxidase and enoyl-CoA hydratase/3 hydroxyacyl-CoA dehydrogenase (the so-called peroxisomal bifunctional enzyme of the beta-oxidation system) were found to be diminished in carcinoma cells compared with the control tissue. The fall in catalase activity correlated well with tumor stage according to Dukes, suggesting that this peroxisomal enzyme could be used as a potential prognostic marker.