p53 protein expression in peripheral lymphocytes from atrazine chronically intoxicated rats

The p53 expression in peripheral lymphocytes of rats chronically exposed to atrazine was investigated. The experiment was performed in female Wistar rats. Atrazine was administrated in different doses (2.7 and 5.4 mg/kg body weight), each dose once a day, 5 days per week, for 6 and 12 months. The percentage of rats peripheral lymphocytes expressing p53 protein was evaluated by immunocytochemical technique, using a monoclonal antibody (clone PAb 122) against a common epitope, both for the wild type and the mutant p53 protein. The results indicate that in the atrazine long-term administration, the serum level of atrazine is associated with: (i) Significantly increased percentage of lymphocytes expressing p53 protein for all treated animals; (ii) different p53 intracellular compartmentalization (nucleus and cytoplasm), depending on dose and time of atrazine administration. The present study suggests that atrazine modifies the p53 expression, which could confirm the clastogenicity of this herbicide, and that the detection of the p53 protein may serve as a biomarker for the long-term exposure to atrazine.     

The time-related expression of p53 protein in human skin wounds--a quantitative immunohistochemical analysis

Failure to acknowledge ways of knowing in nursing education curricula other than linear reasoning hinders the development of the full extent of mental abilities brought to learning situations by nursing students. Nurse educators are challenged to develop creative methods to facilitate nursing students' intuitive thinking. In this article, a teaching strategy is described in which graduate students' exemplars of intuition in clinical practice are shared with undergraduate nursing students. Implications of using this teaching approach to demystify the intuitive process and address its legitimacy are discussed.     

Disaccharide analysis of human skin glycosaminoglycans in sun-exposed and sun-protected skin of aged people

The negative conduction effect of quinidine on each of the successive phases of the ventricular depolarization was investigated using an original noninvasive method: the spatial velocity electrocardiogram of the QRS complex (SVECG-QRS). We performed a randomized placebo-controlled trial in 10 healthy subjects with a single oral dose of quinidine (330 mg) or placebo. Electrocardiographic acquisition and processing (220 recordings for the complete trial) were performed using the Lyon vectorcardiographic program. For each SVECG-QRS curve, the position of seven specific points from A (onset of QRS) to G (end of QRS) were determined precisely. The six successive time intervals between these points (AB-FG) and five velocity values (B-F) were then calculated. The QRS complex was longer under quinidine than placebo (102.4 +/- 1.6 vs. 100.3 +/- 1.5 ms). The difference was at the periphery of statistical significance (p = 0.05), and this lack of statistical difference may be mainly due to the low serum levels of quinidine obtained at the peak of the concentration (1.46 +/- 0.4 mg/1). All six QRS time intervals were longer under quinidine, but only the BC interval was significantly different (9.3 +/- 1.1 vs. 18.8 +/- 1.1 ms; p < 0.05) suggesting a more pronounced negative conduction effect at the onset of ventricular depolarization. No significant modifications were observed for the velocity values. We conclude that (1) the negative conduction effect of quinidine is heterogeneous, but a further study with a higher dose of quinidine (concentration-dependent effect) is required to confirm this hypothesis and (2) the spatial velocity electrocardiogram of the QRS complex allows a detailed analysis of the ventricular conduction phases. The results of the measurement were found to be reproducible. This noninvasive tool could be used in clinical practice to assess effects of antiarrhythmic drugs on successive ventricular depolarization phases.     

Frequent clones of p53-mutated keratinocytes in normal human skin

The multiple genetic hit model of cancer predicts that normal individuals should have stable populations of cancer-prone, but noncancerous, mutant cells awaiting further genetic hits. We report that whole-mount preparations of human skin contain clonal patches of p53-mutated keratinocytes, arising from the dermal-epidermal junction and from hair follicles. These clones, 60-3000 cells in size, are present at frequencies exceeding 40 cells per cm2 and together involve as much as 4% of the epidermis. In sun-exposed skin, clones are both more frequent and larger than in sun-shielded skin. We conclude that, in addition to being a tumorigenic mutagen, sunlight acts as a tumor promoter by favoring the clonal expansion of p53-mutated cells. These combined actions of sunlight result in normal individuals carrying a substantial burden of keratinocytes predisposed to cancer.     

Prognostic implications of p53 overexpression in cutaneous melanoma from sun-exposed and nonexposed sites

Reduced energy expenditure may predispose children to the development of obesity, but there are limited longitudinal studies to support this theory. We studied 75 white, preadolescent children over 4 y by taking annual measures of body composition and resting energy expenditure (by indirect calorimetry) and two annual measures of total energy expenditure and physical-activity-related energy expenditure (by doubly labeled water). Body composition of parents was assessed at the onset of the study with use of underwater weighing. The major outcome variable was the individual rate of change in fat mass (FM) adjusted for fat-free mass (FFM). The influence of sex, energy expenditure components, initial FM, and parental FM on the rate of change in FM was analyzed by hierarchical linear modeling and analysis of variance. The rate of change in absolute FM was 0.89 +/- 1.08 kg/y (range: -0.44 to 5.6 kg/y). The rate of change in FM adjusted for FFM was 0.08 +/- 0.64 kg/y (range: -1.45 to 2.22 kg/y) and was similar among children of two nonobese parents and children with one nonobese or one obese parent, but was significantly higher in children with two obese parents (0.61 +/- 0.87 kg/y). The major determinants of change in FM adjusted for FFM were sex (greater fat gain in girls), initial fatness, and parental fatness. None of the components of energy expenditure were inversely related to change in FM. The main predictors of change in FM relative to FFM during preadolescent growth are sex, initial fatness, and parental fatness, but not reduced energy expenditure.     

Collagen alterations in chronically sun-damaged human skin

The major histological characteristic of sun-damaged skin is the accumulation of an elastotic material that appears to replace collagen. This elastotic material consists primarily of elastin and histological studies suggest a large loss of collagen in the dermis of chronically sun-damaged skin. In this study, we examine the content and distribution of collagen and procollagen in sun-damaged human skin. The total collagen content of sun-damaged skin was 20% less than nonsolar-exposed skin (524 micrograms collagen per mg total protein in sun-damaged skin and 667 micrograms collagen per mg total protein in nonsolar-exposed skin). In addition, there was a 40% decrease in the content of intact amino propeptide moiety of type III procollagen in sun-damaged skin (0.68 U per 50 mg wet weight) as compared to nonsolar-exposed skin (1.12 U per 50 mg wet weight). The data suggest that this change in collagen content is due to increased degradation. The distribution of collagen in sun-damaged skin was examined by indirect immunofluorescence. Mild digestion of sun-damaged skin with elastase removed the elastin and revealed the presence of collagen in the elastotic material. Therefore, the elastin appears to mask the presence of collagen fibers in the dermis of sun-damaged skin.     

Plasma retinoids after topical use of retinaldehyde on human skin

BACKGROUND: Retinaldehyde (RAL), a natural metabolite of beta-carotene and retinol (ROL), is tolerated by human skin after topical application. PURPOSE: To see if topical application of a large quantity of RAL on human skin is associated with a detectable alteration of constitutive levels of plasma retinoids resulting from metabolism of RAL in the skin. METHODS: Plasma retinoids [ROL, all-trans-retinoic acid (all-trans-RA), RAL, retinyl palmitate/oleate, 13-cis-RA and 4-oxo-13-cis-RA] were analyzed by high-pressure liquid chromatography. Determinations were done in 10 healthy male volunteers kept on a vitamin-A-poor diet before, during and after daily topical application of 7 mg of RAL to 40% of the body surface for 14 days. RESULTS: The introduction of a restricted vitamin A diet before RAL application resulted in a decrease in the plasma levels of ROL, all-trans-RA and retinyl palmitate/oleate. Topical application of RAL did not induce an alteration of the plasma levels of retinoid metabolites. No RAL was detectable in any of the plasma samples. CONCLUSION: The skin metabolism of topically applied RAL does not result in detectable alterations of constitutive levels of plasma retinoids in humans.     

p53 expression in skin carcinogenesis and its relationship to cell proliferation and tumour growth

The immunoreactivity of p53 protein was studied in relation to tumour development, histopathological characteristics, cell proliferation, and basement membrane organisation following the induction of skin carcinogenesis in tumour-sensitive and -resistant mouse strains by ultraviolet (UV) irradiation or 7,12-dimethylbenz(a)anthracene (DMBA). In non-neoplastic skin exposed to UV irradiation or DMBA, p53 immunoreactivity was observed in nearly 50% of the basal layer cells. These cells were morphologically and histochemically indistinguishable from the p53-negative cells, occurring similarly in the tumour-producing and the tumour-negative mouse strains and regardless of subsequent tumour formation. In induced epidermal hyperplasia and in benign tumours, p53-positive and proliferating cells constituted 40-50% of all cells in the basal layer, while superficial cells were p53 negative. In dysplastic epidermis, p53-positive cells and proliferating cells were seen in all cell layers. In the case of squamous cell carcinomas, p53-positive proliferating cells in differentiated neoplasms were localised close to the basement membrane and, more frequently, in border areas showing invasion and basement membrane destruction. In horn cysts, centrally located cells were non-proliferating and p53 negative. In moderately differentiated neoplasms, proliferating cells were located closer to the basement membrane, while p53-positive cells were distributed diffusely in the neoplasm. In poorly differentiated neoplasms, p53-positive cells were more common than proliferating cells and were arranged in a diffuse pattern. The results showed that the number and location of p53-positive cells depended upon histology, with a close relationship to tumour type and degree of malignancy, but not on the mode of induction, nor on the animal strain or the relationship to subsequent tumour formation.     

Baculovirus p33 binds human p53 and enhances p53-mediated apoptosis

In vertebrates, p53 participates in numerous biological processes including cell cycle regulation, apoptosis, differentiation, and oncogenic transformation. When insect SF-21 cells were infected with a recombinant of the baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV) overexpressing human p53, p53 formed a stable complex with the product of the AcMNPV orf92, a novel protein p33. The interaction between p53 and p33 was further confirmed by immunoprecipitation studies. When individually expressed in SF-21 cells, human p53 localized mainly in the nucleus whereas baculovirus p33 displayed diffuse cytoplasmic staining and punctuate nuclear staining. However, coexpression of p33 with p53 resulted in exclusive nuclear localization of p33. In both SF-21 and TN-368 cells, p53 expression induced typical features of apoptosis including nuclear condensation and fragmentation, oligonucleosomal ladder formation, cell surface blebbing, and apoptotic body formation. Coexpression of p53 with a baculovirus inhibitor of apoptosis, p35, OpIAP, or CpIAP, blocked apoptosis, whereas coexpression with p33 enhanced p53-mediated apoptosis approximately twofold. Expression of p53 in SF-21 cells stably expressing OpIAP inhibited cell growth in the presence or absence of p33. Thus, human p53 can influence both insect cell growth and death and baculovirus p33 can modulate the death-inducing effects of p53.     

Altered expression of the p53-regulated proteins, p21Waf1/Cip1, MDM2, and Bax in ultraviolet-irradiated human skin

The gemistocytic astrocytoma is a histological variant of diffuse astrocytomas and is characterised by the presence of large, GFAP-expressing neoplastic astrocytes (gemistocytes) and a tendency towards rapid progression to glioblastoma. In this study, we analyzed 28 gemistocytic astrocytomas (mean fraction of gemistocytes, 35.0+/-9.9%) for mutations in the p53 and PTEN (MMAC1) tumour suppressor genes. Single strand conformation polymorphism (SSCP), followed by direct DNA sequencing of p53 exons 5-8, revealed a mutation in 23 of 28 (82%) cases. Regional analysis of four tumours revealed identical p53 mutations in gemistocytic and fibrillary tumour areas. In contrast, none of 15 gemistocytic astrocytomas (WHO Grade II) and only two of 11 (18%) anaplastic gemistocytic astrocytomas (WHO Grade III) contained a PTEN mutation. Of these, one was a 1 bp deletion in codon 345 and the other a 1 bp insertion in intron 4. Differential PCR did not reveal homozygous PTEN deletion in any of the tumours analysed. These results indicate that p53 mutations are a genetic hallmark of gemistocytic astrocytomas, whilst PTEN mutations are absent in low-grade and rare in anaplastic gemistocytic astrocytomas.     

Sunlight and sunburn in human skin cancer: p53, apoptosis, and tumor promotion

Levels of allergen-specific IgE and IgE antibodies were determined in serum samples from 60 atopic and 11 normal dogs by means of commercially available ELISA test kits and a panel of 33 allergens. In the atopic population, IgE antibodies were most commonly identified with a specificity for Dermatophagoides farinae (78.3 per cent of affected dogs), D pteronyssinus (61.6 per cent), mould mix (25 per cent) and house dust (19 per cent), whereas the most frequently detected IgG antibodies had a specificity for D farinae (38.3 per cent), D pteronyssinus (33.3 per cent), mould mix (33.3 per cent), insect mix (16.6 per cent) and meadow fescue (16.6 per cent). The IgG subclass profile of allergen-specific antibodies was determined for five representative allergens from the panel. The IgG response to D farinae and D pteronyssinus was dominated by IgG4 antibodies, although lower levels of IgG2, and IgG3 and IgG1 D pteronyssinus antibodies were also detected. The IgG response to Timothy grass was predominantly within the IgG1 and IgG4 subclasses, IgG subclass selection in the response to mould mix and insect mix was broader, with relatively low level reactions from all four subclasses. The data suggest a degree of IgG subclass restriction in the humoral immune response of canine atopy which may be dependent upon the nature of the allergen.     

Increased proliferative activity and p53 expression in normal glandular breast tissue after radiation therapy

Macrophage colony-stimulating factor (M-CSF), initially described as a growth factor of the mononuclear phagocytic lineage, also participates in immunological and inflammatory reactions, bone metabolism and pregnancy. All its biological activities are mediated by a tyrosine kinase receptor (M-CSF-R) that is encoded by the c-fms protooncogene. After a brief overview on the synthesis, structure, metabolism and signalling of M-CSF and its receptor, we present with more details the major in vitro and/or in vivo biological activities of this cytokine. A particular attention has been devoted to the results suggesting that the various M-CSF isoforms (i.e. soluble, cell-associated and matrix anchored forms) play different specific roles on target cells bearing M-CSF-R at their surface. Infectious, inflammatory and neoplastic diseases in which M-CSF is involved and could participate to their physiopathology are mentioned. Finally, the role that the various isoforms of M-CSF could play in the regulation of "physiological and pathological cytokine networks" during inflammatory and immune responses is discussed.     

p53 protein expression in extrahepatic bile duct cancer

p53 mutations, a tumor suppressor gene located on chromosome 17p, are the most common genetic alterations found in human cancers. Although the p53 expression or mutation has been investigated in a variety of cancers there have been very few studies in extrahepatic bile duct cancers. In this study, we investigated the immunohistochemical expression of p53 in formalin fixed paraffin embedded archival specimens of 36 extrahepatic bile duct cancers in which p53 expression was found in eighteen (50%) cases. There was no significant difference in age, gender, size of tumor, histologic grade, extent of tumor involvement, lymph node metastasis and tumor resectability according to p53 immunoreactivity. Comparison of survival duration according to p53 expression showed no significant difference. In conclusion, we reported 50 percent of p53 expression in extrahepatic bile duct cancers by immunohistochemical staining and we found no prognostic significance of p53 expression in dinicopathologic parameters.     

Wild-type p53 triggers a rapid senescence program in human tumor cells lacking functional p53

The p53 tumor suppressor gene has been shown to play an important role in determining cell fate. Overexpression of wild-type p53 in tumor cells has been shown to lead to growth arrest or apoptosis. Previous studies in fibroblasts have provided indirect evidence for a link between p53 and senescence. Here we show, using an inducible p53 expression system, that wild-type p53 overexpression in EJ bladder carcinoma cells, which have lost functional p53, triggers the rapid onset of G1 and G2/M growth arrest associated with p21 up-regulation and repression of mitotic cyclins (cyclin A and B) and cdc2. Growth arrest in response to p53 induction became irreversible within 48-72 h, with cells exhibiting morphological features as well as specific biochemical and ultrastructural markers of the senescent phenotype. These findings provide direct evidence that p53 overexpression can activate the rapid onset of senescence in tumor cells.     

Expression of p53 protein and p53 gene transcripts in rabbit carotid arteries after balloon denudation

A case of sinusitis caused by the basidiomycete Schizophyllum commune is reported in a 36-year-old female with a history of allergic rhinitis and dermatitis. The patient presented with sudden nasal obstruction, purulent nasal discharge, headache and general discomfort. Computer tomography revealed extensive opacity of the left maxillary sinus as well as erosion of the nasal wall and maxillary bone. Mycological examinations of nasal discharges and material aspirated during anthrostomy showed hyaline, septate hyphae with rare spicules. Primary isolation yielded a white, woolly mould which demonstrated clamp connections and basidiocarp primordia but these characteristics were lost in subculture. Identification was confirmed by vegetative compatibility studies. The patient was treated with itraconazole to avoid possible postsurgical dissemination. Three months after cessation of therapy, no recurrence of infection had occurred.