Indicadores de calidad del Programa de Detección Precoz de Hipoacusia Permanente del Hospital Padre Hurtado / Quality indicators of the newborn hearing screening program in Hospital Padre Hurtado

Introducción: La detección precoz de hipoacusia permanente en lactantes beneficia el desarrollo integral del paciente. Los programas cuyo objetivo es la identificación universal de hipoacusia debieran tener como meta determinados criterios de calidad en su ejecución. Objetivo: El objetivo del presente trabajo es comunicar los resultados del Programa de Detección Precoz de Hipoacusia en el Hospital Padre Hurtado. Material y método: Se incluyen los recién nacidos entre el 1 de enero de 2014 y el 31 de agosto de 2016. Los pacientes sin factores de riesgo para hipoacusia congénita se evalúan con examen de emisiones otoacústicas, y los pacientes con factores de riesgo con potenciales auditivos automatizados de tronco encefálico. Refieren aquellos pacientes con exámenes alterados en forma uní o bilateral. La etapa diagnóstica incluye potenciales auditivos evocados con tono, impedanciometría de alta frecuencia y audiometría de refuerzo visual. Los pacientes con diagnóstico de hipoacusia permanente son amplificados e inician proceso de habilitación. Resultados: En el período de estudio el universo a evaluar fue de 12.313 recién nacidos. Se completó la etapa de pesquisa en 98.4% con una tasa de referencia de 0.6%. 79 pacientes pasaron a etapa diagnóstica, completaron su evaluación antes de 3 meses en 95% de los casos. Se confirmó hipoacusia sensorioneural en 7 casos, con una tasa de 0.56 por 1.000 recién nacidos vivos. En 57% de los pacientes se amplificaron antes de los seis meses de vida. Conclusiones: El Programa de Hipoacusia Congénita del Hospital Padre Hurtado cumple con los indicadores de calidad recomendados en los ítemes de pesquisa y diagnóstico. En la etapa de habilitación con audffonos esto se realiza antes de los seis meses de vida sólo en 57% de los casos.

Introduction: Quality indicators of the newborn hearing screening program in Hospital Padre Hurtado. Aim: Asses the accomplishment of quality indicators of the newborn hearing screening program in Hospital Padre Hurtado, Chile, as proposed by the Joint Committee on Infant Hearing Loss (JCIH). Material and method: Two stage screening protocol: otoacoustic emissions for babies in the well-infant nursery and automated auditory brainstem responses for those in the intensive care unit orwith risk factors. If they fail one or both ears they proceed to a comprehensive audiological assessment. Results: 12.313 live births between 01/01/2014 and 108/31/16, 12.103 were screened before discharge (98.4%). 79 cases proceeded to diagnostic assessment, referral rate 0.6%. 95% infants completed audiological evaluation before three months, seven cases were diagnose with permanent sensorineural hearing loss for a prevalence of 0.56 per 1000 live births. Amplification was provided before 6 months of age in 57% of deaf children. Conclusions: Quality indicators of the JCIH are met by our newborn hearing screening program with the exception of adequate timing for the provision of hearing aids: 57% before six months of age.

A fast and reliable single-run method for genotyping of the human cytochrome P450 2C8 gene for different ethnic groups.

Patients vary widely in their response to drug therapy according to their genetic background of drug metabolizing enzymes. The cytochrome P450 enzyme CYP2C8 is one of the major metabolizing enzymes involved in drug metabolism and thus a candidate for routine pharmacogenetic screening. The aim of this work was establishing a fast and reliable method to detect the three CYP2C8 genotypes CYP2C8*2, CYP2C8*3, CYP2C8*4, and the wildtype allele. An established real-time polymerase chain reaction (PCR) to detect two CYP2C8 genotypes was extended by introduction of a third hybridization probe. After optimization of running conditions, the new triplex method was evaluated using 200 DNAs of African origin as templates. Standard methods were performed as controls. The new triplex real-time PCR was fast, reliable and reproducible. The obtained results showed no deviation from the results of the established technique. The polymorphism of the CYP2C8 gene among an African population showed the expected distribution (68% wildtype gene, 32% at least one CYP2C8*2 allele). Pharmacogenetics gain increasing interest in routine medical care to prevent severe adverse effects or the application of ineffective drugs. We here provide a fast, reliable and reproducible method in one single assay run to detect three relevant CYP2C8 alleles independent of the patient's ethnic origin.

[Pro- and supination impairments due to torsional deformities of the radial diaphysis before and after ulna osteotomy]. / Pro- und Supinationseinschränkungen bei Torsionsfehlstellungen der Radiusdiaphyse vor und nach Ulnaosteotomie.

The aim of this experimental study was to measure the exact influence of torsional deformities at the middle third of the radial shaft before and after osteotomy of the ulnar shaft on the rotation of the forearm. Intact and fresh cadaver specimens were fixed in a newly developed apparatus that allowed free pronation and supination. A ring fixator was applied to the radial shaft with K wires that allowed torsional deformities to be stabilized in steps of 10 degrees. The middle of the radial shaft was osteotomized via a small soft tissue window leaving the other soft tissues including the interosseous membrane intact. Supination and pronation were measured using a goniometer in a standardized fashion. The mean supination value before osteotomy of the radius was 71.6 degrees [standard deviation (SD)15.2 degrees], the mean pronation value was 64.5 degrees (SD 12.4 degrees). Radial osteotomy caused no significant difference in the range of motion prior to creation of torsional deformities. Supination torsional deformities greater than 30 degrees showed a significant loss of pronation and pronation torsional deformities greater than 30 degrees resulted in a significant loss of supination in 14 fresh cadavers, respectively. The amount of mean rotational loss was approximately the same in the respective pronation and supination torsional deformities. In the next step the influence of an ulna osteotomy on the range of motion was evaluated in different torsional deformities. In the four cadavers measured, there was an increase of the range of motion in the direction of the torsional deformity. These values were not significant when compared to values before ulna osteotomy, but there were significant changes to the non deformity (p=0.004 for pronation, p=0.003 for supination). Impairment of range of motion in the opposite direction of the deformity showed a similar appearance as values before ulna osteotomy. Again, there were significant changes to the non deformity (p=0.003 for pronation, p=0.005 for supination).

Kinematics of the ulna during pronation and supination in a cadaver study: implications for elbow arthroplasty.

OBJECTIVE: Aim of this study was to exactly describe and quantify kinematics of the ulna during pro- and supination. DESIGN: Biomechanical study in fresh frozen cadavers. BACKGROUND: A previous MRI study revealed a varus/valgus motion of the ulna averaging 7.1 degrees during pro-/supination. Axial rotation, however, could not be quantified. METHODS: Sixteen arms were examined in a new apparatus that fixed the humerus on a template and allowed forearm rotation. Motion of a Kirschner wire placed in the ulna was recorded in steps of 30 degrees by two perpendicularly arranged charge coupled device cameras during pro- and supination. RESULTS: From supination to pronation the ulna showed a semi-lunar evasive motion in the coronal and transverse plane with an initial varus shift, then a dorsal and finally a valgus shift. Motion in the coronal plane averaged 14.14 degrees (SD 4.78). Valgus angles of the ulna in 30 degrees, 60 degrees and 90 degrees pronation were significant (P<0.05) to each other and the neutral position. Varus angles of the ulna in 30 degrees, 60 degrees and 90 degrees supination (P<0.01) were significant to each other and the neutral position.A maximum ulnar axial pronation rotation of 3.2 degrees (SD 2 degrees ) was noted. Axial rotation angles of 90 degrees and 60 degrees of pronation were significant to each other and to the neutral position (P<0.05), respectively. CONCLUSIONS: To prevent increased stress on the bone-cement interface in elbow arthroplasty, a mean axial rotation of at least 3.2 degrees should be possible.

Computer simulation of forearm rotation in angular deformities: a new therapeutic approach.

A new computer-assisted simulation of forearm rotation based on orthogonal radiographs of the forearm is introduced. A new computer program called STOOPS was developed based on a new kinematic model describing motion of the radius and ulna in regards to forearm rotation. The computer program allows simulation of angular deformities of the forearm and can predict subsequent rotational impairment. To validate the program, the authors compared the actual pronation of 21 patients with angular deformities with the predicted pronation by STOOPS. The mean difference between the simulated and clinically measured pronation was 5.6 degrees (S.D. 9.4 degrees ). There was no statistically significant difference between the measured and simulated values. Using the computer-assisted simulation may help predict impairment of pronation due to angular deformities. If clinical impairment differs from the computed one, other causes such as lesions to the interosseous membrane or the adjacent joints have to be excluded. If values are similar, correction of the angular deformities should result in improvement of forearm pronation.

[Pronation and supination of the forearm. With special reference to the humero-ulnar articulation]. / Die Pro- und Supination des Unterarms. Unter besonderer Berücksichtigung der Articulatio humeroulnaris.

The development of a kinematic model of the pro- and supination, that can be used to predict the influence of angulations of ulna and radius on the pronation and supination is based on the precise knowledge of the pronation and supination movement. We performed two parallel studies for examining the pronation and supination motion of the human forearm. The first experiment dealt with MRI-studies on 18 probands (36 examined forearms). As a result we observed an evasive movement of the ulna during the rotation of 7, 14 degrees medial. In order to prove whether the evasive movement was caused by a rotation of the humerus or by an evasion in the articulatio humeroulnaris, we carried out a second experiment, using 30 preparations. The measurement of the pro- and supination motion with a fixed humerus was expedited using a special experimental setup which guaranteed that the ulna could move freely. In all cases we found the same magnitude of the evasive motion of the ulna. Therefore we demonstrated, that the ulna performs an evasive motion during the pro- and supination motion of the forearm that influences the kinematic behavior of the pro- and supination motion significantly.

Calcium levels correlate with cell cycle phase and affect the level of the cyclin B transcript in Dictyostelium discoideum.

In pre-aggregation amoebae of Dictyostelium discoideum, phenotypic differences with respect to cellular Ca2+ and cell cycle phases are known to bias post-aggregative cell-type choice. Using chlortetracycline fluorescence as an indicator, we found that cellular Ca2+ is highest at the S phase of the cell cycle. Upon increasing the level of Ca2+ with the help of the calcium ionophore A23187, there is a significant decrease in the cyclin B (clb1) mRNA level; the cdc2 mRNA level shows a marginal decrease. These results suggest that the effect of Ca2+ and the cell cycle on cell fate could be exerted at the level of transcription, or message stability, of specific genes.

Expression of a cell surface antigen in Dictyostelium discoideum in relation to the cell cycle.

We have previously shown binding of a monoclonal antibody MUD 9 to the cell surface of Dictyostelium discoideum amoebae and slug cells. In the slug stage the prestalk region was predominantly labelled, while vegetative amoebae showed a great heterogeneity in binding. In the present paper it is shown that the heterogeneous label of vegetative amoebae is due to differences in MUD 9 binding by cells in different cell cycle phases. Cells were synchronized by dilution from stationary phase and the level of MUD 9 binding was determined. Synchrony was determined by investigating increase in cell number and changes in the volume distribution of the cells, and by estimating the number of cells in S phase by monitoring bromodeoxyuridine (BUdR) incorporation. Simultaneously the amount of MUD 9 binding was determined by quantitative microscopy and flow cytometry. The amount of MUD 9 label varies during the cell cycle. The highest amount of label is found on cells early in the cell cycle, i.e. S-phase. These results support the finding that the developmental fate of Dictyostelium discoideum cells depends among other things on the cell cycle position of the cells at the moment of starvation.

Use of a monoclonal antibody recognizing a cell surface determinant to distinguish prestalk and prespore cells of Dictyostelium discoideum slugs.

Double labelling experiments on Dictyostelium discoideum cells at different developmental stages were carried out using monoclonal antibodies MUD1 (prespore specific), MUD9 (strong label on prestalk and anterior-like cells) and a fluorescence-activated cell sorter. The monoclonal antibody MUD9, which recognizes the surface of prestalk and anterior-like cells strongly and prespore cells weakly, is also present on the surface of vegetative amoebae and on mature stalk cells but not on the spore surface. Sharing of an antigenic determinant between vegetative, prestalk and anterior-like cells is consistent with these cells being 'less differentiated' than prespore cells.

Flow cytometer study of anterior-like cells in Dictyostelium discoideum.

The Dictyostelium discoideum asexual fruiting body consists of spores, stalk and basal disk cells. Recently, a fourth cell class has been proposed. It has been suggested that these cells originate from anterior-like cells that remain undifferentiated. Anterior-like cells are randomly distributed among prespore cells in the posterior part of the slug. Here monoclonal antibodies that recognize the surface of prespore cells (MUD1), and spores (MUD3) are used in a quantitative flow cytometer assay to demonstrate that this fourth cell class does not exist in the mature fruiting body. However, the tip cells are slow to differentiate, and hence immature fruiting bodies contain a small population of undifferentiated tip cells. We confirm that anterior-like cells represent a large percentage of the non-prespore cell population in the slug. In this report we were unable to distinguish these anterior-like cells from prestalk cells on the basis of size or monoclonal antibody staining.

An assay for pattern formation in dictyostelium discoideum using monoclonal antibodies, flow cytometry, and subsequent data analysis.

An assay for determining the proportions of prespore cells in a simple multicellular organism, the slug stage of Dictyostelium discoideum, was established using a prespore-specific monoclonal antibody and a fluorescence-activated cell sorter. Appropriate techniques for data analysis were developed. The effects of slug size and age were determined. Small slugs have a lower percentage of prespore cells than large slugs. The percentage of prespore cells increases and then decreases in slugs aged between a few hours and 9 days. Pronounced effects were observed on the size of cells in aging slugs. In particular unlabelled (mostly prestalk) cells were larger than prespore cells in young slugs, but after 6 days migration they became considerably smaller than prespore cells. The fact that all unlabelled cells were coordinately shifted in size, suggests that these cells (which comprise prestalk, prestalklike, and predisc cells) are related to each other.

Evidence that positional information is used to establish the prestalk-prespore pattern in Dictyostelium discoideum aggregates.

Two contrasting mechanisms have been proposed for the establishment of the prestalk-prespore pattern in the multicellular aggregate of the simple eukaryote Dictyostelium discoideum. One involves intermingled, non-position-dependent cell differentiation followed by sorting out which produces the pattern of prestalk cells in the anterior region and prespore cells posteriorly. The second mechanism involves patterning according to the position of cells within the aggregate, in which case intermingled cell types are not expected. Here we use a monoclonal antibody (MUD1), recognising a prespore cell surface antigen, to study the initial appearance of prespore cells in aggregates. Quantitative studies were made with a flow cytometer and frozen sections were used to localise the cells expressing the prespore antigen. This antigen first appeared at the onset of tip formation in the centre of aggregates in a position-dependent fashion. The prespore antigen was not detected in the tip region or in streams of cells entering the aggregate. We re-examined the evidence on which the non-position-dependent differentiation model is based. Our results support the positional model for pattern formation.

Analysis of proportion regulation in slugs of Dictyostelium discoideum using a monoclonal antibody and a FACS-IV.

A quantitative assay for estimating the proportion of prespore cells in D. discoideum slugs was established by labelling disaggregated slug cells with a prespore specific monoclonal antibody and analysing the cell population with a FACS-IV. The method is validated using a wild-type strain and its stalky mutant. "Wild-type" strains have different proportions of prespore cells and it is demonstrated that slugs of some strains have an increased percentage of prespore cells when migrated in the dark compared to the light and in the presence of EGTA. The technique is rapid and will make possible genetic analysis of proportion regulation in D. discoideum.

Antigenic differences detected between prespore cells of Dictyostelium discoideum and Dictyostelium mucoroides using monoclonal antibodies.

A method was developed to obtain frozen sections of paraformaldehyde-fixed Dictyostelium slugs. These sections were ideal for studies using monoclonal antibodies. Two different monoclonal antibodies were used to recognize specific antigens on the surface of D. discoideum prespore cells by fluorescence microscopy. Neither of the two monoclonal antibodies bound to D. discoideum prestalk cells. D. mucoroides, a closely related species to D. discoideum, failed to bind either monoclonal antibody to its prespore cells. These results contrast with those obtained with either D. mucoroides [1] or D. discoideum [2] polyspecific antisera.

Flow-cytometric measurements of the transmembrane potential, the surface charge density and the phagocytic activity of Guinea pig macrophages after incubation with lymphokines.

The effects of lymphokines on guinea pig peritoneal macrophages were measured via flow cytometry utilizing the three-parameter FLUVO-METRICELL flow cytometer. On the basis of cell volume three distinct macrophage populations could be distinguished. Three to 5 min after starting the incubation with lymphokines a hyperpolarization of all three macrophage populations took place which was followed by depolarization. After 60 min the transmembrane potential reached again its control values. The negative charge density of the cell membrane decreased shortly after beginning of the incubation to 70-80% of the initial value and then remained unchanged for the following 120 min. The phagocytic activity of the macrophages was diminished during the depolarisation phase but increased over control values after restoration of the transmembrane potential.