Fridrikh Niṭshe un zayn filosofisher anṭṿiḳlungs-gang

Ḥ. Zshiṭloṿsḳi

Gene expression profile in newborn rat lungs after two days of recovery of mechanical ventilation.

BACKGROUND Preterm infants having immature lungs often require respiratory support, potentially leading to bronchopulmonary dysplasia (BPD). Conventional BPD rodent models based on mechanical ventilation (MV) present outcome measured at the end of the ventilation period. A reversible intubation and ventilation model in newborn rats recently allowed discovering that different sets of genes modified their expression related to time after MV. In a newborn rat model, the expression profile 48 h after MV was analyzed with gene arrays to detect potentially interesting candidates with an impact on BPD development. METHODS Rat pups were injected P4-5 with 2 mg/kg lipopolysaccharide (LPS). One day later, MV with 21 or 60% oxygen was applied during 6 h. Animals were sacrified 48 h after end of ventilation. Affymetrix gene arrays assessed the total gene expression profile in lung tissue. RESULTS In fully treated animals (LPS + MV + 60% O(2)) vs. controls, 271 genes changed expression significantly. All modified genes could be classified in six pathways: tissue remodeling/wound repair, immune system and inflammatory response, hematopoiesis, vasodilatation, and oxidative stress. Major alterations were found in the MMP and complement system. CONCLUSION MMPs and complement factors play a central role in several of the pathways identified and may represent interesting targets for BPD treatment/prevention.Bronchopulmonary dysplasia (BPD) is a chronic lung disease occurring in ~30% of preterm infants born less than 30 wk of gestation (1). Its main risk factors include lung immaturity due to preterm delivery, mechanical ventilation (MV), oxygen toxicity, chorioamnionitis, and sepsis. The main feature is an arrest of alveolar and capillary formation (2). Models trying to decipher genes involved in the pathophysiology of BPD are mainly based on MV and oxygen application to young mammals with immature lungs of different species (3). In newborn rodent models, analyses of lung structure and gene and protein expression are performed for practical reasons directly at the end of MV (4,5,6). However, later appearing changes of gene expression might also have an impact on lung development and the evolution towards BPD and cannot be discovered by such models. Recently, we developed a newborn rat model of MV using an atraumatic (orotracheal) intubation technique that allows the weaning of the newborn animal off anesthesia and MV, the extubation to spontaneous breathing, and therefore allows the evaluation of effects of MV after a ventilation-free period of recovery (7). Indeed, applying this concept of atraumatic intubation by direct laryngoscopy, we recently were able to show significant differences between gene expression changes appearing directly after MV compared to those measured after a ventilation-free interval of 48 h. Immediately after MV, inflammation-related genes showed a transitory modified expression, while another set of more structurally related genes changed their expression only after a delay of 2 d (7). Lung structure, analyzed by conventional 2D histology and also by 3D reconstruction using synchrotron x-ray tomographic microscopy revealed, 48 h after end of MV, a reduced complexity of lung architecture compared to the nonventilated rat lungs, similar to the typical findings in BPD. To extend these observations about late gene expression modifications, we performed with a similar model a full gene expression profile of lung tissue 48 h after the end of MV with either room air or 60% oxygen. Essentially, we measured changes in the expression of genes related to the MMPs and complement system which played a role in many of the six identified mostly affected pathways.

Cigarette smoking and cervical intraepithelial neoplasia among colposcopy patients

Epidemiologic and biochemical evidence suggest that smoking is an independent risk factor for cervical neoplasia; however, only two studies have adjusted by the potential confounding effect of human papillomavirus (HPV). To determine the association between self-reported current cigarette smoking and cervical intraepithelial neoplasia (CIN), we conducted a case-control study that controlled for HPV infection and other reported risk factors. The medical records of all new patients referred to the University of Texas M. D. Anderson Cancer Center (UTMDACC) Colposcopy Clinic were reviewed. The study population (n = 564) consisted of all white, black, and Hispanic non-pregnant women who were residents of Texas, and had no history of treatment for cervical neoplasia. Cases (n = 313) included women diagnosed at the UTMDACC with CIN; while controls (n = 251) included those patients diagnosed at the colposcopy clinic as non-CIN (negative 47%, inflammation or atypia 25%, and koilocytosis 27%). Diagnosis was based on a colposcopically directed biopsy in 95% of the subjects, and all subjects were tested for HPV by dot blot hybridization. The crude odds ratio for cigarette smoking and CIN was 1.37 (95% CI 0.97-1.95); however, after adjusting for HPV, age, education, race, number of sexual partners, and age at first sexual intercourse, the odds ratio decreased to 0.91 (95% CI 0.61-1.41). A higher crude odds ratio was observed with CIN 3 (OR = 1.75, 95% CI 1.08-2.83), but this effect also disappeared after adjustment (OR = 1.06, 95% CI 0.57-1.96). Similar results were observed when controlling only for HPV: OR = 1.11 (95% CI 0.77-1.59) for CIN combined and 1.25 (95% CI 0.76-2.08) for CIN 3. These findings suggest that cigarette smoking is not an independent risk factor for CIN in this population, and that HPV may be an important confounding factor for this association. ^

RB-mediated suppression of spontaneous multiple neuroendocrine neoplasia and lung metastases in Rb+/− mice

Alterations in pathways mediated by retinoblastoma susceptibility gene (RB) product are among the most common in human cancer. Mice with a single copy of the Rb gene are shown to develop a syndrome of multiple neuroendocrine neoplasia. The earliest Rb-deficient atypical cells were identified in the intermediate and anterior lobes of the pituitary, the thyroid and parathyroid glands, and the adrenal medulla within the first 3 months of postnatal development. These cells form gross tumors with various degrees of malignancy by postnatal day 350. By age of 380 days, 84% of Rb+/− mice exhibited lung metastases from C-cell thyroid carcinomas. Expression of a human RB transgene in the Rb+/− mice suppressed carcinogenesis in all tissues studied. Of particular clinical relevance, the frequency of lung metastases also was reduced to 12% in Rb+/− mice by repeated i.v. administration of lipid-entrapped, polycation-condensed RB complementary DNA. Thus, in spite of long latency periods during which secondary alterations can accumulate, the initial loss of Rb function remains essential for tumor progression in multiple types of neuroendocrine cells. Restoration of RB function in humans may prove an effective general approach to the treatment of RB-deficient disseminated tumors.

Tumor burden and clonality in multiple intestinal neoplasia mouse/normal mouse aggregation chimeras

Aggregation chimeras were formed between C57BL/6 mice heterozygous for the Apcmin (Min) mutation and wild-type SWR mice, that differ in their Pla2g2a status, a modifier of Apcmin, and also in their resistance to intestinal polyp formation. Variation in the dolichos biflorus agglutinin-staining patterns of the intestines of these mouse strains was used to determine the chimeric composition of the intestine in individual mice and to examine the clonal composition of adenomas. Macroscopic adenoma numbers in chimeric mice were compared with the expected adenoma numbers based on the percentage of C57BL/6J-Apcmin/+ epithelium in individual mice. These results unexpectedly show that there was no apparent inhibitory effect of the SWR-derived (Pla2g2a wild-type) tissue on adenoma formation in the C57BL/6J-Apcmin/+ epithelium. This suggests that the main genetic modifiers of the Min phenotype act at a cellular or crypt-restricted level with no discernable systemic effect. All adenomas were seen to contain C57BL/6J-Apcmin/+-derived epithelium, confirming that the germ-line mutation of the mApc gene is necessary to initiate tumorigenesis in this model system, and that the mApc gene acts in a cell autonomous fashion.

A resistant genetic background leading to incomplete penetrance of intestinal neoplasia and reduced loss of heterozygosity in ApcMin/+ mice

Previous studies of Min/+ (multiple intestinal neoplasia) mice on a sensitive genetic background, C57BL/6 (B6), showed that adenomas have lost heterozygosity for the germ-line ApcMin mutation in the Apc (adenomatous polyposis coli) gene. We now report that on a strongly resistant genetic background, AKR/J (AKR), Min-induced adenoma multiplicity is reduced by about two orders of magnitude compared with that observed on the B6 background. Somatic treatment with a strong mutagen increases tumor number in AKR Min/+ mice in an age-dependent manner, similar to results previously reported for B6 Min/+ mice. Immunohistochemical analyses indicate that Apc expression is suppressed in all intestinal tumors from both untreated and treated AKR Min/+ mice. However, the mechanism of Apc inactivation in AKR Min/+ mice often differs from that observed for B6 Min/+ mice. Although loss of heterozygosity is observed in some tumors, a significant percentage of tumors showed neither loss of heterozygosity nor Apc truncation mutations. These results extend our understanding of the effects of genetic background on Min-induced tumorigenesis in several ways. First, the AKR strain carries modifiers of Min in addition to Mom1. This combination of AKR modifiers can almost completely suppress spontaneous intestinal tumorigenesis associated with the Min mutation. Second, even on such a highly resistant genetic background, tumor formation continues to involve an absence of Apc function. The means by which Apc function is inactivated is affected by genetic background. Possible scenarios are discussed.

Selective association of the methyl-CpG binding protein MBD2 with the silent p14/p16 locus in human neoplasia

DNA methylation of tumor suppressor genes is a common feature of human cancer. The cyclin-dependent kinase inhibitor gene p16/Ink4A is hypermethylated in a wide range of malignant tissues and the p14/ARF gene located 20 kb upstream on chromosome 9p21 is also methylated in carcinomas. p14/ARF (ARF, alternative reading frame) does not inhibit the activities of cyclins or cyclin-dependent kinase complexes; however, the importance of the two gene products in the etiology of cancer resides in their involvement in two major cell cycle regulatory pathways: p53 and the retinoblastoma protein, Rb, respectively. Distinct first exons driven from separate promoters are spliced onto the common exons 2 and 3 and the resulting proteins are translated in different reading frames. Both genes are expressed in normal cells but can be alternatively or coordinately silenced when their CpG islands are hypermethylated. Herein, we examined the presence of methyl-CpG binding proteins associated with aberrantly methylated promoters, the distribution of acetylated histones H3 and H4 by chromatin immunoprecipitation assays, and the effect of chemical treatment with 5-aza-2′-deoxycytidine (5aza-dC) and trichostatin A on gene induction in colon cell lines by quantitative reverse transcriptase–PCR. We observed that the methyl-CpG binding protein MBD2 is targeted to methylated regulatory regions and excludes the acetylated histones H3 and H4, resulting in a localized inactive chromatin configuration. When methylated, the genes can be induced by 5aza-dC but the combined action of 5aza-dC and trichostatin A results in robust gene expression. Thus, methyl-CpG binding proteins and histone deacetylases appear to cooperate in vivo, with a dominant effect of DNA methylation toward histone acetylation, and repress expression of tumor suppressor genes hypermethylated in cancers.

A potential pathogenetic mechanism for multiple endocrine neoplasia type 2 syndromes involves ret-induced impairment of terminal differentiation of neuroepithelial cells.

Germ-line missense mutations of the receptor-like tyrosine kinase ret are the causative genetic event of the multiple endocrine neoplasia (MEN) type 2A and type 2B syndromes and of the familial medullary thyroid carcinoma. We have used the rat pheochromocytoma cell line, PC12, as a model system to investigate the mechanism or mechanisms by which expression of activated ret alleles contributes to the neoplastic phenotype in neuroendocrine cells. Here we show that stable expression of ret mutants (MEN2A and MEN2B alleles) in PC12 cells causes a dramatic conversion from a round to a flat morphology, accompanied by the induction of genes belonging to the early as well as the delayed response to nerve growth factor. However, in the transfected PC12 cells, the continuous expression of neuronal specific genes is not associated with the suppression of cell proliferation. Furthermore, expression of ret mutants renders PC12 cells unresponsive to nerve growth factor-induced inhibition of proliferation. These results suggest that induction of an aberrant pattern of differentiation, accompanied by unresponsiveness to growth-inhibitory physiological signals, may be part of the mechanism of action of activated ret alleles in the pathogenesis of neuroendocrine tumors associated with MEN2 syndromes.

Características clínico-epidemiológicas dos doentes com neoplasia da cabeça e pescoço referenciados ao departamento de otorrinolaringologia

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Dermatomiosite, neoplasia da mama e Orlistat : que associação?

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Ascite no contexto de neoplasia invasiva da mama : relato de um caso clínico e revisão da literatura

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Report of the EPA peer review workshop on alpha 2u-globulin : association with renal toxicity and neoplasia in the male rat /

Mode of access: Internet.