Genomic copy number alterations in non-syndromic hearing loss.

Genetic heterogeneity has made the identification of genes related to hearing impairment a challenge. In the absence of a clear phenotypic aetiology, recurrence risk estimates are often based on family segregation and may be imprecise. We profiled by oligonucleotide array-CGH patients presenting non-syndromic hearing loss with presumptive autosomal recessive (n = 50) or autosomal dominant (n = 50) patterns of inheritance. Rare copy number variants (CNVs) were detected in 12 probands; four of the detected CNVs comprised genes previously associated with hearing loss (POU4F3, EYA4, USH2A, and BCAP31) and were considered causative, stressing the contribution of genomic imbalance to non-syndromic deafness. In six cases, segregation of the CNVs in pedigrees excluded them as causative. In one case, segregation could not be investigated, while in another case, a point mutation likely explains the phenotype. These findings show that the presumptive patterns of inheritance were incorrect in at least two cases, thereby impacting genetic counselling. In addition, we report the first duplication reciprocal to the rare ABCD1, BCAP31, and SLC6A8 contiguous deletion syndrome; as with most microduplication syndromes, the associated phenotype is much milder than the respective microdeletion and, in this case, was restricted to hearing impairment.

[Hemodiafiltration with endogenous reinfusion in chronic inflammation: a possible therapeutic alternative?]. / L'impiego dell' Emodiafiltrazione con reinfusione endogena (HFR) nell'infiammazione cronica idiopatica: una possibile alternativa terapeutica?

The patients under maintenance haemodialysis (HD) continue to have an unacceptably excess of mortality compared to general population, that may be explained by high prevalence of inflammation that significantly influences the survival of these patients. Indeed, chronic inflammation is very common in HD and it may cause malnutrition and progression of atherosclerotic disease by several pathogenetic mechanisms triggered by pro-inflammatory cytokines. Currently no pharmacological intervention is specifically targeted the idiopathic chronic inflammation. Hemodiafiltration with endogenous reinfusion (HFR) is a dialysis technique, highly biocompatible, that combines three depurative mechanisms: diffusion, convection and absorption. The ultrafiltrate is obtained from convective section of dialyzer (convection). It is regenerated by passing through the adsorbent macro-porous synthetic resin cartridge (absorption) and then it is reinfused into the second section of the filter (diffusion). This resin cartridge is able to absorb cytokines and other uremic toxins, whereas allows to pass nutrients and antioxidants, as amino acids and vitamins, with a consequent decrement of inflammation and oxidative stress. These characteristics suggest the use of HFR in HD patients affected by overt and idiopathic chronic inflammation. In these patients, we observed that the switching from Bic-HD to HFR allowed an improvement of inflammatory as testified by a significant decrement of serum levels of CRP IL-6, IL-1 and TNF- and a significant increase of albumin and pre-albumin. Whether these favorable effects may modify the outcomes of these high-risk patients, needs to be confirmed by studies ad-hoc.

Multilocus family-based association analysis of seven candidate polymorphisms with essential hypertension in an african-derived semi-isolated brazilian population.

Background. It has been widely suggested that analyses considering multilocus effects would be crucial to characterize the relationship between gene variability and essential hypertension (EH). Objective. To test for the presence of multilocus effects between/among seven polymorphisms (six genes) on blood pressure-related traits in African-derived semi-isolated Brazilian populations (quilombos). Methods. Analyses were carried out using a family-based design in a sample of 652 participants (97 families). Seven variants were investigated: ACE (rs1799752), AGT (rs669), ADD2 (rs3755351), NOS3 (rs1799983), GNB3 (rs5441 and rs5443), and GRK4 (rs1801058). Sensitivity analyses were further performed under a case-control design with unrelated participants only. Results. None of the investigated variants were associated individually with both systolic and diastolic BP levels (SBP and DBP, respectively) or EH (as a binary outcome). Multifactor dimensionality reduction-based techniques revealed a marginal association of the combined effect of both GNB3 variants on DBP levels in a family-based design (P = 0.040), whereas a putative NOS3-GRK4 interaction also in relation to DBP levels was observed in the case-control design only (P = 0.004). Conclusion. Our results provide limited support for the hypothesis of multilocus effects between/among the studied variants on blood pressure in quilombos. Further larger studies are needed to validate our findings.

Intradialytic changes of plasma amino acid levels: effect of hemodiafiltration with endogenous reinfusion versus acetate-free biofiltration.

During hemodialysis, amino acids (AA) are lost in the ultrafiltrate with consequent modification of their plasma profile. The aim of this cross-sectional study was to evaluate intradialytic changes of plasma AA levels during a single session of hemodiafiltration with endogenous reinfusion (HFR) versus acetate-free biofiltration (AFB). 48 patients chronically treated with HFR or AFB were matched 1:1 for age, gender, Kt/V and diabetes. Blood samples were collected at the beginning and the end of dialysis. Baseline plasma levels (µmol/l) of total AA (3,176 ± 722), essential AA (889 ± 221), and branched chain AA (459 ± 140) levels in HFR were similar to those in AFB (3,399 ± 621, 938 ± 277, and 463 ± 71, respectively). Plasma intradialytic AA levels did not change in HFR, while in AFB there was a reduction by about 25%. In conclusion, as compared with AFB, HFR has a sparing effect on AA loss due to the lack of adsorption by cartridge and to their complete reinfusion in blood.

Chromosome imbalances in syndromic hearing loss.

The cause of hearing impairment has not been elucidated in a large proportion of patients. We screened by 1-Mb array-based comparative genomic hybridization (aCGH) 29 individuals with syndromic hearing impairment whose clinical features were not typical of known disorders. Rare chromosomal copy number changes were detected in eight patients, four de novo imbalances and four inherited from a normal parent. The de novo alterations define candidate chromosome segments likely to harbor dosage-sensitive genes related to hearing impairment, namely 1q23.3-q25.2, 2q22q23, 6p25.3 and 11q13.2-q13.4. The rare imbalances also present in normal parents might be casually associated with hearing impairment, but its role as a predisposition gene remains a possibility. Our results show that syndromic deafness is frequently associated with chromosome microimbalances (14-27%), and the use of aCGH for defining disease etiology is recommended.

A novel missense mutation p.L76P in the GJB2 gene causing nonsyndromic recessive deafness in a Brazilian family.

Mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a major cause of nonsyndromic recessive hearing loss in many countries. We report here on a novel point mutation in GJB2, p.L76P (c.227C>T), in compound heterozygosity with a c.35delG mutation, in two Brazilian sibs, one presenting mild and the other profound nonsyndromic neurosensorial hearing impairment. Their father, who carried a wild-type allele and a p.L76P mutation, had normal hearing. The mutation leads to the substitution of leucine (L) by proline (P) at residue 76, an evolutionarily conserved position in Cx26 as well as in other connexins. This mutation is predicted to affect the first extracellular domain (EC1) or the second transmembrane domain (TM2). EC1 is important for connexon-connexon interaction and for the control of channel voltage gating. The segregation of the c.227C>T (p.L76P) mutation together with c.35delG in this family indicates a recessive mode of inheritance. The association between the p.L76P mutation and hearing impairment is further supported by its absence in a normal hearing control group of 100 individuals, 50 European-Brazilians and 50 African-Brazilians.

A novel missense mutation p. L76P in the GJB2 gene causing nonsyndromic recessive deafness in a Brazilian family

Mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a major cause of nonsyndromic recessive hearing loss in many countries. We report here on a novel point mutation in GJB2, p.L76P (c.227C>T), in compound heterozygosity with a c.35delG mutation, in two Brazilian sibs, one presenting mild and the other profound nonsyndromic neurosensorial hearing impairment. Their father, who carried a wild-type allele and a p.L76P mutation, had normal hearing. The mutation leads to the substitution of leucine (L) by proline (P) at residue 76, an evolutionarily conserved position in Cx26 as well as in other connexins. This mutation is predicted to affect the first extracellular domain (EC1) or the second transmembrane domain (TM2). EC1 is important for connexon-connexon interaction and for the control of channel voltage gating. The segregation of the c.227C>T (p.L76P) mutation together with c.35delG in this family indicates a recessive mode of inheritance. The association between the p.L76P mutation and hearing impairment is further supported by its absence in a normal hearing control group of 100 individuals, 50 European-Brazilians and 50 African-Brazilians.

Correspondence regarding Ballana et al., "Mitochondrial 12S rRNA gene mutations affect RNA secondary structure and lead to variable penetrance in hearing impairment".

Ballana et al. [E. Ballana, E. Morales, R. Rabionet, B. Montserrat, M. Ventayol, O. Bravo, P. Gasparini, X. Estivill, Mitochondrial 12S rRNA gene mutations affect RNA secondary structure and lead to variable penetrance in hearing impairment, Biochem. Biophys. Res. Commun. 341 (2006) 950-957] detected a T1291C mutation segregating in a Cuban pedigree with hearing impairment. They interpreted it as probably pathogenic, based on family history, RNA conformation prediction and its absence in a control group of 95 Spanish subjects. We screened a sample of 203 deaf subjects and 300 hearing controls (110 "European-Brazilians" and 190 "African-Brazilians") for the mitochondrial mutations A1555G and T1291C. Five deaf subjects had the T1291C substitution, three isolated cases and two familial cases. In the latter, deafness was paternally inherited or segregated with the A1555G mutation. This doesn't support the hypothesis of T1291C mutation being pathogenic. Two "African-Brazilian" controls also had the T1291C substitution. Six of the seven T1291C-carriers (five deaf and two controls) had mitochondrial DNA of African origin, belonging to macrohaplogroup L1/L2. Therefore, these data point to T1291C substitution as most probably an African non-pathogenic polymorphism.

[Nutritional and energy metabolism changes in abdominal irradiation--experimental study]. / Alterações nutricionais e do metabolismo anergético na irradiação abdominal-estudo experimental.

In this study the effects on nutritional status and energetic metabolism due to abdominal irradiation were analysed. Adult male Wistar rats (48), were divided in two groups Control (C) and Radiated (R). The rats were maintained all time in metabolic cages. The study was done in two periods: Period 1 begun at 0 day, where rats adapted to cages and oral diet, had food and water "ad libitum". At the day 4 indirect calorimetric measurements were performed (calorimetry I). At Period 2, group R rats abdominal radiation at a 300cGy/day rate, for 5 consecutive days, and group C started a pair feeding process linked individually to R rats and suffered application of simulated-radiation. Two other calorimetric measurements (II,III) were performed during Period 2. After radiation the last calorimetry was performed (IV). At sacrifice (day 14) blood was collected for determination of hemoglobin, haematocrit, albumin and transferrin. There were no statistical differences among groups C and R during Period 1 (p < 0.05). Great reduction in food intake and weight variation were found in Period 2, but weight loss was significantly higher in R rats. Nitrogen balance decreased in Period 2, but without difference among the groups (p < 0.05). Serum albumin was significantly lower in R rats. Respiratory quotient decreased in both groups during Period 2, but R rats kept it lower (p < 0.05). The energy expenditure level decreased after radiation in Group R. During Period 2 total substrate oxidation decreased in R rats. Radiation decreased glucose and protein oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Energy metabolism and experimental malignant tumor development]. / Metabolismo energético e desenvolvimento de tumor malígno experimental.

Weight loss in cancer can be attributed to anorexia and/or increased energy expenditure. In order to understand the contribution of these variables, 36 Wistar rats fed regular diet were randomly distributed in 3 groups: T (12) bearing Walker 256 carcinosarcoma; PF (12) pair fed with T group and C (12) as control group; another group--D (12)--in which rats were fed with low protein (1%) diet. Caloric intake, body and tumor weight were measured daily. Indirect calorimetry was done sequentially each 4 days. After 2 weeks of tumor growth there was significant reduction of caloric intake and carcass weight in T group compared to those of C group. There was no difference in carcass weight between T and PF group. After 3 weeks it was significantly reduced in T group (55.7 Kcal/m2/h against 75.0 of N and 65.1 of PF group). Walker 256 carcinosarcoma is an hypometabolic tumor and the host weight loss associated to its development is due to anorexia.

[Effects of protein malnutrition on the metabolic response to trauma]. / Efeitos da desnutrição protéica sobre a resposta metabólica ao trauma.

An experimental study was carried out in rats with the purpose to evaluate post-traumatic metabolic changes in the animals submitted to proteic malnutrition. Rats fed with diets with different contents were submitted to a standardized osteomuscular trauma and had nitrogen balance and body composition parameters analysed. After 21 days of feeding with normoproteic diet chow (N) or hypoproteic diet (D) all the animals were submitted to a dorsal skin wound (subgroups NJ (6) and DJ (6). Besides the skin wound part of the rats suffered also the osteomuscular trauma (subgroups NF (6) and DF (6). After 14 days of osteomuscular trauma all the rats were sacrificed and the carcasses were prepared for body composition measurements. Body weight, food intake, fecal and urinary total nitrogen were measured daily. It was observed that in rats with normoproteic diet the osteomuscular trauma promoted a decrease of food intake and loss of weight; in animals on hipoproteic diet it was observed an increase in total urinary nitrogen output and reduction of nitrogen balance. However, there was no reduction of food intake, loss of body weight and changes in composition of body compartments.

4-Epidoxorubicin activity in experimental malignant tumors

A literatura tem indicado a atividade positiva da doxorrubicina sobre adenocarcinomas gastrointestinais, seja isoladamente, seja em associacao com outros quimioterapicos. Permanece, porem, a critica representada pela toxicidade da droga, o que tem levado a pesquisa de derivados mais toleraveis e igualmente atuantes; e o caso da 4-epidoxorrubicina (4-EPI). E estudada a atividade da 4-EPI sobre o tumor maligno experimental denominado carcinossarcoma de Walker 256. Para tanto, foi observado o comportamento de 48 ratos Wistar adultos dividos aleatoriamente em cinco grupos: grupo T (seis ratos), com animais que receberam implante subcutaneo de celulas do tumor de Walker na regiao do flanco; grupo TE (11 ratos), em que os animais recebiam o implante tumoral, tal como descrito e simultaneamente a injecao endovenosa de 1 mg de 4-EPI na veia caudal; grupo T6E (oito ratos), em que os animais recebiam a 4-EPI, na dose referida, 6 dias apos o implante tumoral; grupo E (11 ratos) apenas injetados com a 4-EPI, sempre por via endovenosa; grupo C (12 ratos), que servia de controle para o comportamento dos demais grupos. Os animais de todos os grupos eram mantidos em gaiolas metabolicas individuais, recebendo dieta padronizada. Diariamente eram registrados: quantidade de dieta ingerida; peso corporeo;...

[Influences of antitumoral chemotherapy on body composition and nitrogen balance: experimental study]. / Conseqüências da quimioterapia antitumoral sobre a composição corpórea e o balanço nitrogenado: estudo experimental.

An experimental study was carried out with the purpose to examine the 4-epidoxorubicine (4-EPI) action on malignant tumor development and its repercussion on nutritional conditions of the host. Cancer and chemotherapy can generate malnutrition. In order to study the nutritional repercussions, 48 host Wistar rats were divided into 5 groups: Group C: 12 control rats; Group T: 5 rats bearing Walker-256 carcinosarcoma; Group TE: 11 rats given 4-epidoxorubicine (4-EPI) EV simultaneously with tumor implantation; Group T6E: 8 rats given 4-EPI 6 days after the tumor implantation; Group E: 11 rats given only 4-EPI. Tumor and carcass weight and nitrogen balance (by measuring total nitrogen ingested and excreted) were determined daily; the animals were sacrificed on the 20th day of the experiment and material was collected for determination of body composition parameters. A variance analysis was made and the differences were considered to be significative at p less than 0.05. A loss of food during a period following the 4-EPI injection was reflected by carcass weight loss. The accumulated nitrogen incorporation was lower in Groups TE and T6E in the periods of 0-5 days, 0-14 days, and 0-20 days. As for body composition it was verified that free fat solids and total body fat were reduced in Groups T ant T6E when compared to group C. However, 20 days after the use of 4-EPI there were no significative changes in the body composition. In rats bearing Walker-256-carcinosarcoma 4-EPI was effective.(ABSTRACT TRUNCATED AT 250 WORDS)