Genotypes B and C hepatocellular carcinoma-associated hepatitis B virus pre-S mutants: their detection among F1b and A2 - but not F4 - isolates from Argentina.

Prevalence rates of hepatocellular carcinoma (HCC)-associated hepatitis B virus (HBV) pre-S mutants among most genotypes are still lacking. In this study, viral (sub)genotypes of 70 Argentine nucleotide sequences (33 newly obtained) were determined by phylogenetic analysis, and the presence of such mutants was assessed in the American continent for the first time. Nucleotide substitutions of the pre-S2 start codon were observed in 10% of the HBV/A2 sequences. Ten per cent of the HBV/A2 and 12.5% of the HBV/F1b - but none of HBV/F4 - exhibited a deletion in the pre-S1/pre-S2 region. The contribution of these variants to liver cirrhosis (LC) and/or HCC development among HBV/F and HBV/A isolates deserves further prospective clinical studies.

Late endosomal membranes rich in lysobisphosphatidic acid regulate cholesterol transport.

The fate of free cholesterol released after endocytosis of low-density lipoproteins remains obscure. Here we report that late endosomes have a pivotal role in intracellular cholesterol transport. We find that in the genetic disease Niemann-Pick type C (NPC), and in drug-treated cells that mimic NPC, cholesterol accumulates in late endosomes and sorting of the lysosomal enzyme receptor is impaired. Our results show that the characteristic network of lysobisphosphatidic acid-rich membranes contained within multivesicular late endosomes regulates cholesterol transport, presumably by acting as a collection and distribution device. The results also suggest that similar endosomal defects accompany the anti-phospholipid syndrome and NPC.

Prevalence of children exposed to secondhand smoke at home and in the car in Azores (Portugal).

OBJECTIVES: To identify the prevalence of exposure to secondhand smoke (SHS) at home and in the car among children attending the 4th grade in Azores. METHODS: This is a cross-sectional study that assessed children's exposure to SHS in a convenience sample of school children attending the 4th grade in all primary schools of Azores. The entire population of 4th graders from all elementary schools in Azores were asked to participate in the study (n=2463) in 2017. A validated self-reported questionnaire was administered to 2092 students who delivered the signed informed consent form. We analyzed frequencies, contingency tables, and performed Chi-square tests. RESULTS: Results showed that 56.1% (95% CI 54.0-58.2) children reported having, at least, one smoking parent. Overall exposure to SHS at home was 38.4% (95% CI 36.3-40.6), and overall exposure to SHS in the car was 27.6% (95% CI 25.8-29.3). Children whose parents were smokers reported being more exposed to SHS at home (63.6%; 95% CI 58.6-68.3) than children whose parents were non-smokers (32.3%; 95% CI 30.2-34.6). CONCLUSION: The results showed that the children's exposure to SHS in Azores is high and it tends to be higher than the prevalence found in mainland Portugal. Having parents who smoke is a major risk factor for children's exposure to SHS at home. These data justify a population-wide intervention plan for preventing tobacco consumption and children's exposure to SHS in Azores.

Orbital metastasis diagnosed by ultrasound-guided fine-needle aspiration biopsy: Case report of unknown primary site. / Metástasis de la órbita diagnosticada por biopsia por aspiración con aguja fina guiada por ultrasonido: reporte de caso de sitio primario desconocido.

Twenty five percent of orbital metastasis is usually of unknown primary origin and it requires histopathological and immunohistochemical confirmation. The fine-needle aspiration biopsy of the orbit is an alternative procedure to conventional orbitotomy. The case is presented of a 60 year-old woman with a right orbit tumour mass and neoplastic lesions in her brain and cranium. As an incidental finding, she had a thrombus in her left atrium, and so an orbitotomy procedure was ruled out. An ultrasound-guided fine-needle aspiration biopsy was performed instead with rapid on-site evaluation of biopsy samples. These showed malignant cells of a lung adenocarcinoma, which was confirmed with immunohistochemistry and chest diagnostic images. In conclusion, biopsy samples obtained by fine-needle aspiration biopsy, together with cytopathological and immunohistological analysis, enabled orbital metastasis to be identified in the case described, and showed that fine-needle aspiration biopsy is a safe, effective, and minimally invasive alternative.

Oropharyngectomy without mandibulotomy in advanced stage (T3-T4) oropharyngeal cancer.

CONCLUSIONS: The postoperative course was excellent for this type of surgery, and the functional recovery was comparable to that obtained with much more laborious techniques. OBJECTIVES: To compare the advantages and disadvantages of the described technique and oropharyngectomy with labial mandibulotomy. PATIENTS AND METHODS: A total of 46 patients underwent surgery by means of an oropharyngectomy without mandibulotomy. The pharynx was reconstructed using a plasty made of four regional flaps. RESULTS: In addition to obvious esthetic benefits, complications of the osteotomy were absent and surgical time was reduced. Some patients undergoing pull-through oropharyngectomy also underwent a marginal mandibulectomy, markedly reducing the frequency of radionecrosis compared with other statistics of techniques using mandibulotomy.

Interferon alpha-2a as alternative treatment for conjunctival squamous cell carcinoma. / Interferón alfa-2a como tratamiento alternativo para el carcinoma conjuntival de células escamosas.

CASE REPORT: A 35 year-old male patient with a history of HIV infection characterized by progressive tumour growth in bulbar conjunctiva of the left eye, corresponding to conjunctival squamous cell carcinoma that responded to treatment with interferon alpha-2a. DISCUSSION: Interferon alpha-2b has been used at conjunctival level as a topical immunomodulator treatment, with complete remission of epithelial neoplasms being observed. However, there have not been any previous publications on the use of interferon alpha-2a, which differs from interferon alpha-2b in a single amino acid, for the treatment of conjunctival squamous cell carcinoma.

Chromosome instability with bleomycin and X-ray hypersensitivity in a boy with Nijmegen breakage syndrome.

We report on a Mexican boy with microcephaly, short stature, and a high frequency of chromosome aberrations with rearrangements involving chromosomes 7 and 14, typical of ataxia telangiectasia (AT) patients. He had neither ataxia nor telangiectasia, and his immunological status and serum alpha feto protein (AFP) level were normal. Bleomycin hypersensitivity, which has been demon-strated in AT patients, was tested in the patient using AT and normal subjects for comparison. The frequency of spontaneously occurring chromosome aberrations in lymphocyte cultures was significantly higher in the patient and the AT patient than in the normal subject. Four cells from the patient showed structural rearrangements involving chromosomes 7 or 14, with breakpoints typical for AT. When exposed to 5.0 micrograms bleomycin, the lymphocytes from the AT patient showed the highest sensitivity to this agent; our patient had an intermediate sensitivity. In both patients several rearrangements involving chromosomes 7 and 14 were scored, while none were observed in the normal subject. A colony survival assay (CSA) [Huo et al., 1994: Cancer Res 54:2544-2547], using a lymphoblastoid cell line (LCL) derived from our patient, showed a survival fraction (SF) of 7%, which is in the same range as in AT patients. The clinical picture, together with the cytogenetic and radiosensitivity results, suggests that our patient fits the variable spectrum of Nijmegen breakage syndrome.

Delayed repair of DNA damage by ionizing radiation in cells from patients with juvenile systemic lupus erythematosus and rheumatoid arthritis.

We used a single-cell alkaline gel electrophoresis (SCAGE) assay to study repair of primarily single-stranded DNA breaks after in vitro exposure to ionizing radiation in cells from children with systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (JRA), systemic sclerosis (SSc) and dermatomyositis. Peripheral blood lymphocytes from patients with SLE, JRA and SSc had significantly greater DNA damage after irradiation with 1.5 Gy and 30 min incubation (i.e. repair time) than did those from controls, as assessed by the length of the migrating DNA comet. The mean comet tail lengths were: SLE, 42 microns; JRA, 40 microns; and SSc, 36 microns. Each of these was significantly different from controls, which had a mean comet tail length of 18 microns (P < 0.001, < 0.001 and < 0.05, respectively). Cells from patients with dermatomyositis had an average comet tail length of 22 microns and were not significantly different from controls. Understanding the etiology of the delay in DNA repair in these diseases may provide insight into disease pathogenesis.

Optimisation of a solid-phase microextraction procedure for the determination of triazines in water with gas chromatography-mass spectrometry detection.

A procedure based on solid-phase microextraction (SPME) and gas chromatography-mass spectrometry, operating in the chemical ionisation mode, was developed and optimised in order to determine 10 triazines in water samples. Five different SPME fibers available for analysis [polydimethylsiloxane (PDMS) 100 microm, polyacrylate (PA) 80 microm, PDMS-divinylbenzene (DVB) 65 microm, Carbowax (CW)-DVB 65 microm, and Carboxen (CAR)-PDMS 75 microm] were tested, and PDMS-DVB was selected. To enhance the sensitivity of the SPME, variables affecting adsorption and desorption steps such as temperature, time, pH and ionic strength of the solution were optimised. Detection limits obtained were ranged between 2 and 17 ng l(-1), and precision values were below 8% for the selected PDMS-DVB fiber. The optimised method was applied to real water samples and no triazines were detected.

Comparison of different coatings in solid-phase microextraction for the determination of organochlorine pesticides in ground water.

A solid-phase microextraction (SPME) procedure using three commercialised fibers (Carbowax-divinylbenzene, Carboxen-polydimethylsiloxane and divinylbenzene-Carboxen-polydimethylsiloxane) is presented for the determination of a selected group of organochlorine compounds in water samples. The extraction performances of these compounds were compared using fibers with two and three coatings. The optimal experimental procedures for the adsorption and desorption of pesticides were determined. The limits of detection with the divinylbenzene-Carboxen-polydimethylsiloxane fiber at levels below ng l(-1) were similar or lower than values presented in the literature for several of these compounds using polydimethylsiloxane fiber. The advantages of using this fiber, such as no salt addition, are discussed. Finally, the optimised procedures were applied successfully for the determination of these compounds in polluted ground water samples.

Cytogenetics in acute lymphoblastic leukemia in Mexican children: an institutional experience.

BACKGROUND: Cytogenetic studies in acute lymphoblastic leukemia (ALL) have identified numerical and structural chromosomal abnormalities related to the disease's pathophysiologic characteristics. These findings correlate with prognosis and response to treatment in ALL patients. The purpose of this study was to define the frequency of chromosomal abnormalities in a group of Mexican children with ALL and to compare these data with those reported in the literature. METHODS: Bone marrow chromosome studies with GTG bands were performed in 150 pediatric patients with ALL who were naive to antileukemic treatment and aged from 5 months to 16 years; the majority was diagnosed as L1. RESULTS: Among 131 patients, 30 (22.9%) karyotypes were normal and the remaining 101 (77.1%) had abnormal karyotypes with numerical and/or structural abnormalities. Among patients with numerical abnormalities, the most frequent karyotypes were hyperdiploidy with 51-65 chromosomes (30 patients) and hyperdiploidy with 47-50 chromosomes (18 patients). Among recurrent, non-random, and primary structural abnormalities, the most frequent was t(9;22), followed by t(1;19). Aberrations involving band 11q23 were not detected, and only one of two patients with L3 had the t(8;14). Of the secondary non-random abnormalities, dup(1q), del(6q), and i(7)(q10) were found. CONCLUSIONS: The frequency and type of chromosomal abnormalities found was comparable to those reported in the literature with similar methodology and pediatric populations; however, the number of cases analyzed should be increased to create a database of Mexican children with ALL, and several patients require molecular analysis to identify chromosomal abnormalities not detected through conventional cytogenetic studies.

Effect of hydroxyurea and normal plasma on DNA synthesis in lymphocytes from Fanconi anemia patients.

Fanconi anemia (FA) is characterized at the cellular level by a high frequency of spontaneous chromosomal aberrations; crosslinking agents cause an abnormal increase in the frequency of chromosomal damage, and semiconservative DNA synthesis is severely inhibited. Deoxyribonucleotides are needed in both semiconservative and repair DNA synthesis. To investigate the involvement of deoxyribonucleotide pools in the inhibition of DNA synthesis in FA, we evaluated the effect on FA lymphocytes of hydroxyurea (HU), an inhibitor of ribonucleotide reductase which is known to alter the intracellular levels of deoxyribonucleotides. To achieve this goal, lymphocyte cultures of 4 FA patients and 4 normal individuals were used. Cultures were treated with HU and/or mitomycin C and normal human plasma. All cultures were processed to detect the number of DNA synthesizing nuclei by autoradiography. Scoring of 2000 nuclei for each kind of culture every 6 h in the last 24 h of incubation showed that, in long incubation periods, DNA synthesis in FA is largely inhibited by HU and this hypersensitivity may be partially decreased by addition of normal human plasma. It is known that recovery from damage induced by HU involves several enzymes such as flavin oxido-reductase, superoxide dismutase and catalase which are involved in the production or scavenging of O2 radicals; FA cells are deficient in the detoxification of oxygen and this could explain the response of FA cells to HU.

[Synergism of bromodeoxyuridine and mitomycin C in the production of chromosomal aberrations in Fanconi's anemia]. / Sinergismo bromodesoxiuridina-mitomicina C en la produccion de aberraciones cromósomicas en anemia de Fanconi.

Synergism of BrdU and MMC on the production of chromosome aberrations in lymphocytes of patients with Fanconi's anemia (FA) was studied. With this purpose, the lymphocytes of an FA patient and of a normal subject were cultured and exposed to BrdU and to MMC in 6 different experiments. The results showed no synergism of these two agents in normal cells. However FA cells exposed to BrdU and MMC showed an increased frequency of aberrations suggesting synergism. Furthermore the chromosome damage produced by MMC was significantly increased by the presence of BrdU in the medium. These results support the hypothesis of a defect of DNA repair in FA cells.

[Effect of mitomycin C (MMC) on the fusion points of reciprocal translocations]. / Acción de la mitomicina C (MMC) sobre los puntos de fusión de translocaciones recíprocas.

Lymphocytes from five patients having a reciprocal translocation were exposed to MMC to test the stability of the point of reunion which was localized in an euchromatic region. The results showed that the point of fusion in this type of translocations in not a preferential breakpoint. In a patient carrier of a (1;7) translocation, the derivate chromosome showed a significant increased number of breaks compared with the homologous chromosomes. No explanation is available for this finding. Our results support the hypothesis that the observed dissociation of Robertsonian translocation is related to the fact that the point of reunion is located in a heterochromatic region.

[Effects of the addition of conditioned media on the response of Fanconi anemia lymphocytes to mitomycin C]. / Efecto de la adición de medios condicionados sobre la respuesta de los linfocitos de anemia de Fanconi a la mitomicina-C.

It has been shown that the addition of normal plasma to Fanconi anemia (FA) lymphocyte cultures significantly decreases the frequency of mitomycin C (MMC) induced chromosome aberrations, suggesting that normal plasma contains a diffusible correction factor (CF) which is able to partially complement FA lymphocytes. On the other hand, there is evidence suggesting that FA cells are defective in the DNA postreplicative repair. CF could then be involved in DNA repair processes and in possible inducible mechanisms. In the present study MMC-treated FA lymphocytes were grown during the last 24 hours of culture, in conditioned media obtained from untreated and MMC-treated normal cells. The purpose was to investigate if MMC-stressed normal cells were induced to produce CF in vitro. The results failed to show a constant decrease of FA cells chromosome aberrations when plasma-free conditioned media from MMC-stressed normal cells were added (experiments 2 and 3). However, when the conditioned media were supplemented with normal plasma (experiments 1 and 4) a partial repair of MMC-induced damage of the FA cells was observed. The results suggest the presence of CF in normal plasma and two possible mechanisms of action are suggested: CF is involved in DNA repair of MMC-damaged FA cells or it induces cellular division selecting the less damaged cell population through mitosis.

[Effect of gamma radiations on robertsonian translocations]. / Acción de las radiaciones gama sobre las traslocaciones robertsonianas.

Centromeric breaks and the dissociation of Robertsonian translocations have been regarded as the possible cause of a few reported cases of mosaicism. In a previous study we suggested that the dissociative phenomenon is influenced by an instability of the point of fusion, when it is located on a heterochromatic region, which appears to be a preferential mitomycin C (MMC) breakpoint. In this study lymphocytes from 6 robertsonian translocation carriers were treated with gamma rays. In one case who was a mosaic, the MMC induced a statistically significant increase in the number of cells with the dissociation. In the remaining cases, centromeric breaks or complete fissions were observed in 1.8% of the cells. In addition, the analysis of the distribution of breakage points on heterochromatic or euchromatic regions showed that almost 50% of the breaks on translocation chromosomes were located on pericentromeric heterochromatin. We postulate that the dissociation which occurs in robertsonian translocations may be caused by instability of the point of fusion since it is located on a heterochromatic region, susceptible to breakage by clastogenic agents such as MMC and gamma rays.

[Fluorescence in situ hybridization in 6 patients with alterations of chromosome 18 and in 7 with marker chromosomes]. / Hibridación in situ con fluorescencia en seis pacientes con alteraciones del cromosoma 18 y en siete con cromosomas marcadores.

The purpose of the present study was to use the FISH method to establish the origin of chromosome aberrations currently unidentifiable by routine banding procedures. It was done in 13 cases with structurally rearranged chromosomes, seven of them with non-satellited marker chromosomes; in two of the latter an isochromosome 18p was identified which was consistent with a clinical picture of a tetrasomy 18p. FISH with chromosome-specific painting probes showed a deletion 18q in a girl with a cytogenetically balanced t(8;18). Two patients with deletions and two with 18 ring chromosomes were studied using a telomeric probe: both deletions had telomeric integrity and telomeric material was not present in the 18 rings. In a patient with an abnormal chromosome 18, the FISH analysis confirmed a pericentric inversion. We conclude from these results that FISH can provide a rapid and unequivocal cytogenetic diagnosis, which may improve genetic counseling.

[Detection of aneuploidies using in situ hybridization in cells of the oral mucosa]. / Detección de aneuploidías por hibridación in situ en células de mucosa oral.

Aneuploidies have been traditionally diagnosed by chromosome analysis, however this method may be difficult to perform in certain cellular types or in severely ill patients. With the fluorescence in situ hybridization (FISH) technique it is possible to identify the number of specific chromosomes in interphase cells. In the present study we analyzed exfoliated epithelial cells from the oral mucosa of 15 patients with trisomy 21, and in six patients with mosaicism; five normal subjects were included for comparison. To allow the probe to reach its target DNA we first treated the keratin-surrounded membrane with pepsin during 20 minutes. In the 15 cases of trisomy 21, the cells showed five fluorescent signals indicating the presence of three chromosomes 21 and two 13, while the normal subjects showed four signals. In one girl with Turner syndrome and a karyotype 46,X+mar, the FISH analysis in 1000 cells revealed that the marker derived from chromosome X and there was a mosaicism 45,X/46,X,r(X). In the other patients with mosaicisms, we observed variations in the proportions of cells but the differences were not significant. In conclusion, interphase FISH on buccal cells showed to be a rapid, effective and non-invasive method for the diagnosis of chromosome aberrations, particularly when the cytogenetic study on lymphocytes is difficult to perform.

Persistent genomic instability in peripheral blood lymphocytes from Hodgkin lymphoma survivors.

Advances in cancer treatment have led to an increase in patient survival. However, exposure to genotoxic chemotherapeutic agents and ionizing radiation may induce persistent genetic damage in cancer survivors. In this study, we detected genomic instability in chromosomes of peripheral blood lymphocytes from Hodgkin lymphoma patients, 2-17 years after MOPP (nitrogen mustard, Oncovin, procarbazine, and prednisone) chemotherapy with or without radiotherapy. Samples were obtained from 11 healthy individuals, 5 pretreatment patients, and 20 posttreatment patients. Cytogenetic analysis with GTG banding was performed on 1,000 lymphocyte metaphases per donor to identify genomic instability, including numerical and structural chromosomal aberrations, at a resolution of 10 Mb across the entire genome. Our results showed that anticancer treatment did not induce significant differences in the frequency of aneuploidy among the three study groups. However, 1 of the 11 healthy individuals, and 13 of the 20 posttreatment patients had a high frequency of chromosomal breaks and gross chromosomal rearrangements. The types of aberrations observed were random and complex, consistent with persistent genomic instability that was induced by cancer treatment. Clonal expansion of cells with chromosomal lesions was observed in one posttreatment patient only. These findings show that anticancer treatments induce persistent genomic instability, but not aneuploidy. Chemotherapy may affect genes with a role in DNA damage surveillance or repair, which in turn allows the accumulation of nontargeted structural chromosomal damage in future generations of cells. This genomic instability may facilitate the development of second malignancies in Hodgkin lymphoma survivors.