Demodulation of quasi-quadrature interferometric signals for use in the totally implantable hearing aids.

We propose and experimentally prove an algorithm for demodulation of interferometric signals, modified for use in a totally implantable hearing aid device. A fiber optic configuration, which generates two quasi-quadrature signals by a passive 3x3 coupler, for a non-contact detection of the middle ear ossicle vibration is employed. We simulated the ossicle vibration and large movements and demonstrated the effectiveness of the algorithm to compensate changes of the signal DC values and the phase shift introduced by the coupler. Applying the proposed algorithm we obtained the output signal stability better than 0.5 dB, and the system equivalent input noise of about 31 dB (A) SPL @ 1 kHz.

[Immune response against modified low-density lipoproteins in patients with non-insulin-dependent diabetes mellitus]. / Respuesta inmune contra lipoproteínas de baja densidad modificadas en pacientes con diabetes mellitus no-insulino dependiente.

BACKGROUND: Diabetes mellitus is a risk factor for atherosclerosis. Low density lipoproteins are considered a key factor in the formation of atheroma and the immune system has an important contribution to this process. AIM: To quantify the immune response against modified low density lipoproteins in patients with non insulin dependent diabetes mellitus. MATERIAL AND METHODS: LDLs obtained from blood of healthy subjects, were glycated or altered with malondialdehyde and used as antigens. Serum autoantibodies against these LDLs were measured by ELISA in 22 patients with non insulin dependent diabetes mellitus aged 46 to 67 years old and 13 healthy controls aged 41 to 65 years old. Basal and LDL stimulated tumor necrosis factor a production in vitro, by peripheral leukocytes of diabetics and controls was also measured. RESULTS: The ratio of glycated LDL/native LDL antibodies was higher in diabetics than in controls (9.37 +/- 2.72 and 0.41 +/- 0.11 respectively p < 0.05) and the ratio of MDA modified LDL/native LDL antibodies was not significantly different (8.64 +/- 3.83 and 2.14 +/- 1.26 respectively, NS). Tumor necrosis or production by leukocytes was higher in diabetics than in controls in basal conditions (53.3 +/- 15.3 and 26.9 +/- 14.7 arbitrary units (a.u.) respectively), when stimulated with native LDL (46.5 +/- 5 and 24.3 +/- 9.4 a.u. respectively), when stimulated with malondialdehyde modified LDL (50 +/- 16.2 and 24.4 +/- 7.7 a.u. respectively) or when stimulated with glycated LDL (38.3 +/- 8.8 and 14.4 +/- 7.5 a.u. respectively). CONCLUSIONS: Diabetic patients have an enhanced immune response against low density lipoproteins, factor that could contribute to the accelerated atherogenesis of this disease.

[Serum lipid levels in children and teenagers from Concepción, Chile]. / Perfil lipídico y prevalencia de dislipidemias en niños y adolescentes de Concepción, Chile.

BACKGROUND: There is a relationship between serum lipid levels in children with those of adults. Preventive measures to reduce serum lipid levels should start in childhood. AIM: To study serum lipid levels in a representative sample of children and teenagers from Concepción, Chile. SUBJECTS AND METHODS: Serum total, HDL cholesterol and triglycerides were measured in 1,286 males and 816 females from 5 to 18 years old in the city of Concepción. RESULTS: Mean total cholesterol levels were 159 +/- 30 and 162 +/- 31 mg/dl in males and females respectively. The figures for HDL cholesterol were 46 +/- 11 and 47 +/- 11 mg/dl, for LDL cholesterol were 94 +/- 27 and 96 +/- 29 mg/dl and for triglycerides were 80 +/- 35 and 87 +/- 38 mg/dl. Nine percent of males and 12% of females had a total cholesterol over 200 mg/dl. Likewise 10% of males and 11% of females had a LDL cholesterol over 130 mg/dl. CONCLUSIONS: These numbers will help to plan and perform interventions in children, in order to prevent cardiovascular diseases.

[Lipoprotein in children and adolescents: relationship with family history of coronary artery disease]. / Lipoproteína en niños y adolescentes: relación con historia familiar de enfermedad coronaria.

BACKGROUND: Lipoprotein (a) is considered an independent cardiovascular risk factor. AIM: To study lipoprotein (a) levels in children of 18 years old or less with or without family history of coronary artery disease. SUBJECTS AND METHODS: Forty four children aged between 3 and 18 years old with a family history of coronary artery disease and 44 age and sex matched controls were studied. A fasting blood sample was obtained to measure total, HDL and LDL cholesterol, triglycerides, A1 and B apoproteins and lipoprotein (a). RESULTS: Compared to controls, children with a family history of coronary disease had higher total cholesterol (177 +/- 35 and 159 +/- 23 mg/dl respectively), LDL cholesterol (112 +/- 34 and 94 +/- 21 mg/dl respectively), triglycerides (89 +/- 38 and 71 +/- 25 mg/dl respectively), apoprotein B (85 +/- 17 and 65 +/- 13 mg/dl respectively) and lipoprotein (a) (40 +/- 50 and 22 +/- 31 mg/dl respectively). Thirty two percent of children with positive family history had lipoprotein (a) levels over 30 mg/dl, compared to 23% of controls. CONCLUSIONS: Children with family history of coronary artery disease have higher levels of cholesterol, triglycerides and lipoprotein (a) than matched controls.

[Influence of ethnic and environmental factors the lipid profile in school children from the VIII Region]. / Influencia de la etnia y el ambiente sobre el perfil lipídico en escolares de la VIII región.

We studied fasting total, HDL cholesterol and triglycerides in 329 children aged from 6 to 15 years. One hundred and ten lived in Concepción and were considered urban. Two hundred nineteen lived in Alto Bio-Bio and were considered rural; of these, 173 had a pehuenche aboriginal origin. Rural pehuenche, rural non pehuenche and urban children had a total cholesterol of 123.7 +/- 23, 133.7 +/- 25.8 and 153.7 +/- 29.7 mg/dl respectively, a HDL cholesterol of 39.2 +/- 9.1, 38.8 +/- 9.1 and 46.2 +/- 11.3 mg/dl respectively and triglycerides of 83.3 +/- 33.5, 96.7 +/- 33.5 and 81.9 +/- 33.3 mg/dl respectively. Lipid levels were above safe values in 2.9% of pehuenche, 8.7% non pehuenche rural and 13.6% or urban children. It is concluded that the higher lipid levels of urban and non pehuenche children supports the favorable effect of rural environment and pehuenche ethnic origin on cardiovascular risk factors.

[Effect of cholelithiasis and cholecystectomy on duodenogastric biliary reflux]. / Efecto de la colelitiasis y de la colecistectomia sobre el reflujo duodenogastrico de bilis.

The aim of this work was to study the influence of cholelithiasis and cholecystectomy on duodenogastric biliary reflux. Total bile acid concentration (TBAC) in fasting gastric juice was measured in 23 consecutive patients with cholelithiasis and functioning gallbladder before and at least 3 months after cholecystectomy (group 1) and in 14 healthy volunteers (group II). In group two, TBAC was 8.5 +/- 2.8 uMol/l (mean +/- sem), the preoperative value in group I was 32.8 +/- 8.9 uMol/l and the postoperative value 69.9 +/- 14 uMol/l (p < 0.002 compared with group II and < 0.035 compared with preoperative values). These results suggest that cholelithiasis, even with a functioning gallbladder is associated with a significant increase in bile reflux to the stomach, with raises further after cholecystectomy.

[Risk factors of cardiovascular disease in a Chilean school population: I: Blood lipids in 552 children and adolescents 6-15 years of age]. / Factores de riesgo de enfermedad cardiovascular en una población de escolares Chilenos: I parte: lípidos séricos en 552 niños y adolescentes de 6-15 años.

The distribution of serum cholesterol (TC), low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL)-cholesterol and triglycerides (TG), and the prevalence of risk-considered values were studied in school children from Concepción, Chile (6 to 15 years old; 326 boys, 226 girls). The mean TC levels were 146 mg/dl for boys and 154 mg/dl for girls but 9.1% of the sampled children had TC values between 175 and 190 mg/dl, and 10% were over 190 mg/dl. Mean LDL-C was 83 mg/dl in boys and 89 mg/dl in girls; 6% of samples showed values between 130 and 159 mg/dl, and 1.3% over 160 mg/dl. Mean HDL-C was 46 mg/dl for boys and 48 mg/dl for girls. The mean TG values were 80 mg/dl for boys and 93 mg/dl for girls.