Helicobacter pylori and EBV in gastric carcinomas: Methylation status and microsatellite instability

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genomic instability in non-neoplastic oral mucosa cells can predict risk during 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis

4-Nitroquinotine 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the level of DNA damage induced by 4NQO in oral mucosa cells by the single cell get (comet) assay. Mate Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution by drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Statistically significant increase of DNA damage was observed in non-neoplastic oral cells at four weeks of 4NQO administration when compared with control (P < 0.05). The level of DNA damage was directly associated with the severity of histological changes. The results suggest that histologically normal tissue is able to harbor genetically unstable cells contributing to the initiation of oral carcinogenesis. Genomic instability appears to be associated with the risk and progression of oral cancer. (C) 2004 Elsevier Ltd. All rights reserved.

Genomic instability in blood cells is able to predict the oral cancer risk: an experimental study in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental model of bladder instability in rabbits

OBJECTIVE: Propose a new experimental model of bladder instability in rabbits after partial bladder obstruction. MATERIALS and METHODS: Thirty North Folk male rabbits, weighting 1,700 to 2,820 g (mean: 2,162 g) were studied. The animals were distributed in 2 experimental groups, formed by 15 rabbits each: Group 1 - clinical control. In this group there was no surgical intervention; Group 2 - bladder outlet obstruction. In this group, after anesthetizing the animal, urethral cannulation with Foley catheter 10F was performed and then an adjustable plastic bracelet was passed around the bladder neck. It was then adjusted in order to not constrict the urethra. The following parameters were studied in M1 - pre-operative period; M2 - 4 weeks post-operatively moments: 1)- urine culture; 2)- cystometric study; 3)- serum creatinine and BUN. RESULTS: Bladder weight was 2.5 times larger in the group with obstruction than in the control group. Cystometric evaluation showed a significant increase in maximal vesical volume in the final moment at Group G2. However, there was no statistically significant difference among the groups studied. There was no statistically significant difference between maximal detrusor pressure and vesical compliance in the different moments or in the studied groups. There was an absence of uninhibited detrusor contractions in all the animals in group 1, and involuntary contractions were detected in 93% of group 2 animals. There was no significant variation in BUN and serum creatinine either among the groups or in the same group. CONCLUSIONS: We observed in the group with obstruction a bladder weight 2.5 higher than normal bladders. We detected involuntary contractions in 93% of the animals in group 2, establishing this experimental model as appropriate to secondary bladder instability and partial bladder outlet obstruction.

Estimating genomic instability mediated by Alu retroelements in breast cancer

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Formation of bright solitons and soliton trains in a fermion-fermion mixture by modulational instability

We employ a time- dependent mean- field- hydrodynamic model to study the generation of bright solitons in a degenerate fermion - fermion mixture in a cigar- shaped geometry using variational and numerical methods. Due to a strong Pauli- blocking repulsion among identical spin- polarized fermions at short distances there cannot be bright solitons for repulsive interspecies interactions. Employing a linear stability analysis we demonstrate the formation of stable solitons due to modulational instability of a constant-amplitude solution of the model equations for a sufficiently attractive interspecies interaction. We perform a numerical stability analysis of these solitons and also demonstrate the formation of soliton trains by jumping the effective interspecies interaction from repulsive to attractive. These fermionic solitons can be formed and studied in laboratory with present technology.

Particle creation due to tachyonic instability in relativistic stars

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The modulational instability in deep water under the action of wind and dissipation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Instability zones for satellites of asteroids: The example of the (87) Sylvia system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Allelic imbalance studies of chromosome 9 suggest major differences in chromosomal instability among nonmelanoma skin carcinomas

CONTEXTO: Vários estudos de perda de heterozigozidade na região 9p21-p22, que abriga os genes supressores tumorais CDKN2a/p16INK4a, p19ARF e p15INK4b, têm sido realizados em uma ampla série de tumores humanos, incluindo os melanomas familiares. Perdas e ganhos em outras regiões do cromossomo 9 também têm sido observados com freqüência e podem indicar mecanismos adicionais no processo de tumorigênese dos carcinomas basocelulares da pele. OBJETIVO: Investigar o equilíbrio alélico existente na região 9p21-p22 em carcinomas basocelulares. TIPO DE ESTUDO: Análise molecular de marcadores de microssatélites em tumores e controles. LOCAL: Dois serviços de dermatologia de atendimento terciário em universidades públicas de São Paulo e o Laboratório de Genética Molecular do Câncer da Universidade Estadual de Campinas (UNICAMP), Brasil. PARTICIPANTES: Examinamos 13 casos benignos, incluindo 4 queratoses solares, 3 queratoacantomas, 3 nevos melanocíticos, 2 doenças de Bowen e 1 neurofibroma cutâneo, além de 58 tumores malignos da pele: 14 de células escamosas, 40 carcinomas basocelulares e 4 melanomas; em pacientes consecutivamente encaminhados à clínica de Dermatologia da Unicamp e que concordaram em participar do estudo. VARIÁVEIS ESTUDADAS: O tumor principal e uma porção normal de pele não-adjacente foram removidos cirurgicamente de pacientes que consecutivamente procuraram os ambulatórios de dermatologia da Universidade Estadual de Campinas (UNICAMP) e da Universidade Estadual de São Paulo (Unesp), São Paulo, por causa de lesões cutâneas. Extraímos DNA tanto de tecido tumoral como do correspondente tecido normal de cada paciente. Para amplificar regiões de repetição polimórfica de microssatélites do cromossomo 9, foram utilizados quatro pares de primers, sendo dois deles destinados à região 9p21-p22. RESULTADOS: Identificamos oito casos (20%) de desequilíbrio alélico entre os carcinomas basocelulares, sendo dois casos de perda de heterozigozidade e seis casos de instabilidade de microssatélite na região 9p21-p22. Outros marcadores também mostravam anormalidades em três destes tumores, enquanto nenhuma alteração foi detectada entre os casos benignos e nos outros tumores malignos. CONCLUSÃO: Esta dependência fenotípica sugere que existem diferenças importantes no comportamento das formas mais comuns de tumores cutâneos não-melanocíticos em relação à sua tendência para instabilidade de microssatélite no cromossomo 9. Considerando-se que os genes CDKN2a/p16INK4a, p19ARF e p15INK4b não parecem responsáveis pelas anormalidades observadas, outros genes em 9p21-p22 podem estar envolvidos na etiopatogenia e na progressão dos carcinomas basocelulares.

GENETIC INSTABILITY IN NERVE SHEATH CELL TUMORS

After in vitro culture, we analyzed cytogenetically four acoustic nerve neurinomas, one intraspinal neurinoma and one neurofibroma obtained from unrelated patients. Monosomy of chromosomes 22 and 16 was an abnormality common to all cases, followed in frequency by loss of chromosomes 18 (three cases) and chromosomes 8, 17 and 19 (two cases). Trisomy of chromosome 20 was also detected in two cases. Structural rearrangements were detected at low frequencies, with del(10)(p12) being present in two cases. In addition, we observed cell subpopulations showing a certain degree of genetic instability, reflected by the presence of polyploid cells with inconsistent abnormalities, endoreduplications and telomeric associations resulting in dicentric chromosomes. It is probable that these cytogenetic abnormalities represent some kind of evolutionary advantage for the in vitro progression of nerve sheath tumors.

Influence of ankle functional instability on the ankle electromyography during landing after volleyball blocking

The purpose of this study was to describe, interpret and compare the EMG activation patterns of ankle muscles - tibialis anterior (TA), peroneus longus (PL) and gastrocnemius lateralis (GL) - in volleyball players with and without ankle functional instability (FI) during landing after the blocking movement. Twenty-one players with FI (IG) and 19 controls (CG) were studied. The cycle of movement analyzed was the time period between 200 ms before and 200 ms after the time of impact determined by ground reaction forces. The variables were analyzed for two different phases: pre-landing (200 ms before impact) and post-landing (200 ms after impact). The RMS values and the timing of onset activity were calculated for the three studied muscles, in both periods and for both groups. The co-activation index for TA and PL, TA and GL were also calculated. Individuals with FI presented a lower RMS value pre-landing for PL (CG = 43.0 perpendicular to 22.0; IG = 26.2 perpendicular to 8.4, p < 0.05) and higher RMS value post-landing (CG = 47.5 perpendicular to 13.3; IG = 55.8 perpendicular to 21.6, p < 0.10). Besides that, in control group PL and GL activated first and simultaneously, and TA presented a later activation, while in subjects with FI all the three muscles activated simultaneously. There were no significant differences between groups for co-activation index. Thus, the rate of contraction between agonist and antagonist muscles is similar for subjects with and without FI but the activation individually was different. Volleyball players with functional instability of the ankle showed altered patterns of the muscles that play an important role in the stabilization of the foot-ankle complex during the performance of the blocking movement, to the detriment of the ligament complex, and this fact could explain the usual complaints in these subjects. (C) 2007 Elsevier Ltd. All rights reserved.