Cox regression with doubly truncated responses and time-dependent covariates: the impact of innovation on firm survival.

The creation of new firms is an important incentive for the economic growth of a country, since it generates employment, it encourages the competition, and promotes innovation. In this work, we investigate the survival of Spanish firms which were created since 2001 and closed down between 2004 and 2012. The information was gathered from Technological Innovation Panel (PITEC), a survey with a focus the technological innovation in Spanish firms. In particular, a Cox regression model with time-dependent covariates was used in order to identify and quantify the determinants of the risk of exit for the firm. The selection bias due to the interval sampling for the firms was corrected by using methods for doubly truncated lifetimes. Interestingly, it is seen how the correction for the selection bias changes both the size and the statistical significance of the effects provided by standard Cox regression.

Substance use disorders in patients with intellectual disability admitted to psychiatric hospitalisation.

BACKGROUND: Few studies have looked at the prevalence of substance use disorders (SUD) in people with intellectual disability (ID). The results range between 1% and 6.4% and go up to 20% in people with ID and psychiatric disorders, probably underestimating real prevalence due to several limitations in these studies. ID confers risk for the development of SUD, which in turn will involve negative psychosocial and clinical consequences. We aimed to study the prevalence of SUD in a sample of patients with ID admitted to a brief hospitalisation psychiatric unit, describing them by type and severity and analysing their relationship with clinical, prognostic and access to treatment variables. METHODS: We undertook a descriptive, cross-sectional and retrospective study by means of a review of clinical histories of all patients with a diagnosis of ID, admitted in a period of 10 years. RESULTS: Among the final sample of patients included, 52.3% had a mild ID, 40.9% an unspecified ID, 3.4% a moderate ID and another 3.4% a severe ID. More than one third of the sample met criteria for a SUD. The main SUD was cannabis use disorder (25%), followed by alcohol use disorder (22.7%) and cocaine use disorder (13.6%). The use of more than one substance was the most frequent pattern. Cannabis use disorder and cocaine use disorder were overrepresented in the group with mild ID. A greater number of psychiatric admissions was observed for the group with SUD. Specialised mental health services for ID and specialised addiction network facilities were much less involved in the care of these patients that could be expected according to good clinical practice recommendations. CONCLUSIONS: Substance use disorder in patients with ID and mental health disorders admitted to psychiatric hospitalisation are prevalent, which makes this issue an area of interest for future improvements in case identification, proper referring to specialised treatment resources and an increasing research focusing on specific therapeutic approaches.

Assessing the environmental availability of heavy metals in geogenically contaminated soils of the Sierra de Aracena Natural Park (SW Spain). Is there a health risk?

Soil developed on mineralised bedrock areas of the Sierra de Aracena Natural Park (SW Spain) is geochemically characterised by naturally high levels of heavy metals and metalloids (notably Zn, Pb, Ag and Cd, but also As, Sb, Cu and Tl). To assess environmental availability, geochemical speciation and potential health risk of such geogenic trace elements, 24 randomly selected soil samples were subjected to one-step extraction procedures (0.01M CaCl2 and 0.05M EDTA), aqueous speciation modelling, and site-specific risk analysis. Metal fraction available for plant uptake or leaching to groundwater was found to be negligible (<1%) due to the low activity of dissolved and exchangeable ions in soil solution, as predicted from the CaCl2 extracts. Based on modelling calculations, free metal ions, primarily Cd(2+) and Zn(2+), were the dominant species in solution over the soil pH range of 5.8 to 7.8. For most metals, the EDTA-extractable fraction generally accounted for <5% suggesting that a limited reservoir of trace elements, mainly bound to Fe oxy-hydroxides, could be potentially available. The results of the health risk assessment for ingestion exposure to groundwater affected by soil leaching revealed that the hazard quotients of heavy metals are within the acceptable risk level. The cumulative hazard index (HI=0.55) fell below the regulatory threshold value of 1.0, even in the worst-case scenario being evaluated, leading to the conclusion that no toxic effects are expected to humans under the conditions and assumptions of the assessment.

Automatic assessment of tear film break-up dynamics.

Dry eye syndrome is a common disorder of the tear film which affects a remarkable percentage of the population. The Break-Up Time (BUT) is a clinical test used for the diagnosis of this disease, which computes the time the first tear film break-up appears. This work describes a fully automatic methodology to compute the BUT measurement and evaluate the break-up dynamics until the final blink. This analysis provides useful additional information for the assessment of tear film stability.

Reliability of the non-contact tono-pachymeter Tonopachy NT-530P in healthy eyes.

BACKGROUND: Non-contact Tonopachy NT-530P (Nidek Co., LTD) provides intraocular pressure (IOP) and central corneal thickness (CCT) measurements. This study assesses the reliability and repeatability of its IOP measurements in young healthy adult subjects. METHODS: IOP was determined in the right eye of 64 healthy patients using Tonopachy followed by the Canon TX-10 non-contact and Goldmann applanation (GAT) tonometers. Tonopachy IOP measurements were corrected (Tonopachy-C) or not (Tonopachy-NC) by the instrument for central corneal thickness. Central corneal thickness measurements provided by Tonopachy were also used to correlate (Pearson's coefficient) central corneal thickness with the GAT and Canon TX-10 IOPs. Repeatability of Tonopachy and GAT was assessed in the right eye of 31 subjects in two separate sessions one week apart. Differences between pairs of instruments and between sessions were determined using Bland-Altman plots. The coefficient of repeatability was calculated as the 95% limits of agreement (LoA) of differences between the two sessions. RESULTS: Tonopachy-NC, Tonopachy-C, Canon TX-10 and the Goldmann tonometers showed a mean IOP of 14.62, 15.64, 15.02 and 14.68 mmHg, respectively. Tonopachy-NC and Canon TX-10 readings did not differ significantly from the Goldmann (p > 0.05), with close agreement with both tonometers (GAT versus Tonopachy-NC: -3.84 to 3.96 mmHg; Goldmann versus Canon TX-10: -4.75 to 4.07 mmHg). Tonopachy-C readings differed significantly from Goldmann (mean difference -0.96 mmHg, p = 0.001, LoA from -5.09 to 3.17). Coefficients of repeatability were ± 3.70, ± 3.14 and ± 3.33 mmHg for GAT, Tonopachy-NC and Tonopachy-C, respectively. Central corneal thickness measured with Tonopachy was 530.42 ± 34.96 µm. There was a significant correlation between central corneal thickness and IOP for all tonometers except Tonopachy-C. CONCLUSIONS: Reasonable agreement was observed between the Goldmann and Tonopachy. This instrument provides reliable and repeatable IOP measurements not influenced by central corneal thickness. The Tonopachy-NC and Canon TX-10 offer similar reliability compared to the Goldmann applanation tonometer in a young normotensive population.

The effects of treadmill or overground walking training program on gait in Parkinson's disease.

BACKGROUND: Gait impairment in Parkinson's disease (PD) patients is characterized by the inability to generate appropriate stride length. Treadmill training has been proposed as a therapeutic tool for PD patients. However, it remains unknown whether treadmill training effects are different from overground walking training. Thus, our goal was to explore the effects of two training programs, walking on a treadmill and walking overground, in PD patients. METHODS: 22 PD patients were randomly assigned to a treadmill or overground training group. The training program consisted of 5 weeks (3 sessions/week). Before and after the program we evaluated gait kinematics during walking at preferred and maximal speed; Timed Up and Go (TUG); static posturography and knee extensors strength. Gait parameters were reevaluated in the treadmill training group one month after the cessation of the training. RESULTS: Preferred speed walking improved in both groups after the training program. The treadmill training program, but not the overground, led to an improvement in the stride length at the preferred and maximal walking speed in the PD patients. In addition, the treadmill training group showed improvement of the TUG and static posturography tests. The improvement in gait parameters was maintained one month after the cessation of the treadmill training. CONCLUSIONS: This study provides evidence of a specific therapeutic effect of treadmill training on Parkinsonian gait and balance. Walking on a treadmill may be used as an easy, effective and accessible way to improve the stride length and balance in PD patients.

A two-phase case-control study for colorectal cancer genetic susceptibility: candidate genes from chromosomal regions 9q22 and 3q22.

BACKGROUND: Colorectal cancer (CRC) is the second cause of cancer-related death in the Western world. Much of the CRC genetic risk remains unidentified and may be attributable to a large number of common, low-penetrance genetic variants. Genetic linkage studies in CRC families have reported additional association with regions 9q22-31, 3q21-24, 7q31, 11q, 14q and 22q. There are several plausible candidate genes for CRC susceptibility within the aforementioned linkage regions including PTCH1, XPA and TGFBR1 in 9q22-31, and EPHB1 and MRAS in 3q21-q24. METHODS: CRC cases and matched controls were from EPICOLON, a prospective, multicentre, nationwide Spanish initiative, composed of two independent phases. Phase 1 corresponded to 515 CRC cases and 515 controls, whereas phase 2 consisted of 901 CRC cases and 909 controls. Genotyping was performed for 172 single-nucleotide polymorphisms (SNPs) in 84 genes located within regions 9q22-31 and 3q21-q24. RESULTS: None of the 172 SNPs analysed in our study could be formally associated with CRC risk. However, rs1444601 (TOPBP1) and rs13088006 (CDV3) in region 3q22 showed interesting results and may have an effect on CRC risk. CONCLUSIONS: TOPBP1 and CDV3 genetic variants on region 3q22 may modulate CRC risk. Further validation and meta-analysis should be undertaken in larger CRC cohorts.

Telomerase mRNA expression and immunohistochemical detection as a biomarker of malignant transformation in patients with inflammatory bowel disease

BackgroundInflammatory bowel disease is a premalignant condition for developing colorectal cancer. Since a correlation has been suggested between telomere length, chromosomal instability and neoplastic transformation in this setting, we sought to investigate whether telomerase expression in colorectal mucosa may constitute a biomarker for malignant transformation in patients with inflammatory bowel disease.Patients and methodsForty-seven patients with inflammatory bowel disease with and without cancer or dysplasia were evaluated for human telomerase reverse transcriptase hTERT immunostaining in paraffin-embedded, formalin-fixed colorectal tissues. In addition, hTERT mRNA expression was assessed in fresh frozen specimens from a second set of 35 patients with inflammatory bowel disease at high or low risk for neoplastic transformation.ResultsFive out of 10 patients (50%) with colorectal cancer or high-grade dysplasia exhibited hTERT immunochemical detection in adjacent, non-transformed colonic mucosa. However, this phenomenon was also observed in non-affected mucosa of patients with either long-standing (13 out of 19 patients; 68%) or short duration (13 out of 18 patients; 72%) disease without cancer or dysplasia. On the other hand, hTERT mRNA expression in non-affected colorectal mucosa from patients at high risk for neoplastic transformation due to long-standing disease was higher than in those at low risk (7.42±6.43 vs. 2.87±1.47, respectively; p=0.006).ConclusionsWhereas hTERT immunostaining provides equivocal results, the observation that patients at high risk for colorectal cancer because of long-standing inflammatory bowel disease overexpress hTERT mRNA in non-affected colorectal mucosa suggests its potential usefulness as a biomarker of the risk of malignant transformation(AU)

AntecedentesLa enfermedad intestinal inflamatoria es una condición premaligna para el desarrollo de cáncer colorrectal. Puesto que se ha propuesto la existencia de una correlación entre la longitud de telomero, la inestabilidad cromosómica y la transformación neoplásica en este contexto, nos propusimos investigar si la expresión de la telomerasa en la mucosa colorrectal puede constituir un marcador biológico de transformación neoplásica en pacientes con enfermedad intestinal inflamatoria.Pacientes y métodosSe evaluaron 47 pacientes con enfermedad intestinal inflamatoria, con y sin cáncer o displasia, para inmunotinción de hTERT (transcriptasa inversa de telomerasa humana) en tejidos colorrectales preservados en parafina y fijados con formol. Además, se evaluó la expresión de la ARNm de la hTERT en muestras congeladas procedentes de un segundo grupo de 35 pacientes con enfermedad intestinal inflamatoria clasificados de alto o bajo riesgo de transformación neoplásica.ResultadosCinco de 10 pacientes (50%) con cáncer colorrectal o un grado elevado de displasia presentaban detección inmunoquímica de la hTERT en la mucosa colónica adyacente sin transformación maligna. Sin embargo, este fenómeno también se observó en mucosa no afecta de pacientes que presentaban enfermedad de larga duración (13 de 19 pacientes; 68%) y de corta duración (13 de 18 pacientes; 72%), sin presencia de cáncer ni displasia. Por otro lado, la expresión del ARN de la hTERT en mucosa colorrectal no afecta de pacientes con alto riesgo de transformación neoplásica, debido a enfermedad prolongada, fue mayor que en aquellos con bajo riesgo (7,42±6,43 frente a 2,87±1,47, respectivamente; p=0,006).(..) (AU)

Telomerase mRNA expression and immunohistochemical detection as a biomarker of malignant transformation in patients with inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease is a premalignant condition for developing colorectal cancer. Since a correlation has been suggested between telomere length, chromosomal instability and neoplastic transformation in this setting, we sought to investigate whether telomerase expression in colorectal mucosa may constitute a biomarker for malignant transformation in patients with inflammatory bowel disease. PATIENTS AND METHODS: Forty-seven patients with inflammatory bowel disease with and without cancer or dysplasia were evaluated for human telomerase reverse transcriptase hTERT immunostaining in paraffin-embedded, formalin-fixed colorectal tissues. In addition, hTERT mRNA expression was assessed in fresh frozen specimens from a second set of 35 patients with inflammatory bowel disease at high or low risk for neoplastic transformation. RESULTS: Five out of 10 patients (50%) with colorectal cancer or high-grade dysplasia exhibited hTERT immunochemical detection in adjacent, non-transformed colonic mucosa. However, this phenomenon was also observed in non-affected mucosa of patients with either long-standing (13 out of 19 patients; 68%) or short duration (13 out of 18 patients; 72%) disease without cancer or dysplasia. On the other hand, hTERT mRNA expression in non-affected colorectal mucosa from patients at high risk for neoplastic transformation due to long-standing disease was higher than in those at low risk (7.42+/-6.43 vs. 2.87+/-1.47, respectively; p=0.006). CONCLUSIONS: Whereas hTERT immunostaining provides equivocal results, the observation that patients at high risk for colorectal cancer because of long-standing inflammatory bowel disease overexpress hTERT mRNA in non-affected colorectal mucosa suggests its potential usefulness as a biomarker of the risk of malignant transformation.

Aberrant gene promoter methylation associated with sporadic multiple colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) multiplicity has been mainly related to polyposis and non-polyposis hereditary syndromes. In sporadic CRC, aberrant gene promoter methylation has been shown to play a key role in carcinogenesis, although little is known about its involvement in multiplicity. To assess the effect of methylation in tumor multiplicity in sporadic CRC, hypermethylation of key tumor suppressor genes was evaluated in patients with both multiple and solitary tumors, as a proof-of-concept of an underlying epigenetic defect. METHODOLOGY/PRINCIPAL FINDINGS: We examined a total of 47 synchronous/metachronous primary CRC from 41 patients, and 41 gender, age (5-year intervals) and tumor location-paired patients with solitary tumors. Exclusion criteria were polyposis syndromes, Lynch syndrome and inflammatory bowel disease. DNA methylation at the promoter region of the MGMT, CDKN2A, SFRP1, TMEFF2, HS3ST2 (3OST2), RASSF1A and GATA4 genes was evaluated by quantitative methylation specific PCR in both tumor and corresponding normal appearing colorectal mucosa samples. Overall, patients with multiple lesions exhibited a higher degree of methylation in tumor samples than those with solitary tumors regarding all evaluated genes. After adjusting for age and gender, binomial logistic regression analysis identified methylation of MGMT2 (OR, 1.48; 95% CI, 1.10 to 1.97; p = 0.008) and RASSF1A (OR, 2.04; 95% CI, 1.01 to 4.13; p = 0.047) as variables independently associated with tumor multiplicity, being the risk related to methylation of any of these two genes 4.57 (95% CI, 1.53 to 13.61; p = 0.006). Moreover, in six patients in whom both tumors were available, we found a correlation in the methylation levels of MGMT2 (r = 0.64, p = 0.17), SFRP1 (r = 0.83, 0.06), HPP1 (r = 0.64, p = 0.17), 3OST2 (r = 0.83, p = 0.06) and GATA4 (r = 0.6, p = 0.24). Methylation in normal appearing colorectal mucosa from patients with multiple and solitary CRC showed no relevant difference in any evaluated gene. CONCLUSIONS: These results provide a proof-of-concept that gene promoter methylation is associated with tumor multiplicity. This underlying epigenetic defect may have noteworthy implications in the prevention of patients with sporadic CRC.

Severe complications limit long-term clinical success of self-expanding metal stents in patients with obstructive colorectal cancer.

OBJECTIVES: Self-expanding metal stents (SEMS) are increasingly being used to treat malignant colorectal obstruction. However, complications have been reported in up to 50% of patients. There is limited information on long-term outcomes of these patients. The aim of this study was to retrospectively assess the long-term clinical success of SEMS in patients with malignant colorectal obstruction in a single tertiary center and to identify possible predictive factors of developing complications. METHODS: A total of 47 attempts to insert colorectal SEMS were made in 47 patients during a 5-year period. Stents of 9-cm length were placed under endoscopic and radiologic monitoring. After 24 h, all patients underwent abdominal X-ray to verify correct positioning of the stent. Patients were followed at the outpatient clinic. RESULTS: Insertion success was achieved in 44 (94%) patients. Acceptable initial colonic decompression was observed in 44 out of 47 (94%) attempts and in all (100%) successfully inserted stents. The stents were placed in the rectum (n=7, 15%), sigmoid (n=33, 70%), left colon (n=4, 9%), or anastomosis (n=3, 6%). The majority of patients had stage IV disease (n=40, 85%). SEMS served as a bridge to scheduled surgery in 9 (20%) patients and as a palliative definitive treatment in 38 (80%) cases. Three patients were lost to follow-up, so the outcome was evaluated in 41 patients. Long-term clinical failure occurred in 21 (51%) patients and was due to complications such as: migration (n=9, 22%), obstruction (n=7, 17%), perforation (n=3, 7%), and tenesmus (n=2, 5%). Perforations occurred 3, 4, and 34 days after insertion, and all patients died. In the bridge-to-surgery group, primary anastomosis was possible in only four of nine patients (44%). Clinical failure was not associated with any tumor-related factor. However, eight of nine patients with stent migration and two of three patients with perforation had been previously treated with chemotherapy. CONCLUSIONS: Placement of SEMS does not seem to be as effective as suggested because of late complications. For patients with potentially curable lesions, the use of colonic stents for malignant obstruction should only be considered when surgery is scheduled shortly after the stent insertion. Moreover, in patients with incurable obstructing colorectal cancer eligible for chemotherapy and a long life expectancy, palliative treatments other than SEMS should be considered.

[Psychomotor profile of children between 5 and 12 years of age, clinically diagnosed with attention deficit hyperactivity disorder in Colombia]. / Perfil psicomotor de niños de 5 a 12 años diagnosticados clínicamente de trastorno por déficit de atención/hiperactividad en Colombia.

INTRODUCTION: One of the comorbid alterations of attention deficit hyperactivity disorder (ADHD) affects motricity, to the point where the quality of motor performance during the first 5-6 years of life could constitute a predictor of the later appearance of symptoms of the disorder. Moreover, the association between motor clumsiness and ADHD results in a poorer prognosis of the condition. Nevertheless, few studies have examined the evolution of motricity in children affected with this pathology. AIM: To characterise the psychomotor profile of children between 5 and 12 years of age who were clinically diagnosed with ADHD in the town of Manizales (Colombia) and to compare it with healthy children of the same age. SUBJECTS AND METHODS: A cross-sectional descriptive study was conducted with a sample of 846 children (422 diagnosed with ADHD and 424 healthy controls). RESULTS: Although the values for all the motricity factors were within ranges that are considered to be normal, they were significantly poorer (p < 0.000) in diagnosed children at all ages. CONCLUSIONS: The psychomotor profile of children diagnosed with ADHD was eupraxic and is classified within the same category as the healthy children, although quantitatively it was lower.

[Effect of double anaesthetic Colicursi (tetracaine 0.1% and oxybuprocaine 0.4%) on central and paracentral corneal thickness]. / Efecto de la instilación del colicursi anestésico doble (tetracaína 0,1% y oxibuprocaína 0,4%) sobre el espesor corneal central y paracentral.

OBJECTIVE: To study the effect of 1 drop of combined topical anaesthesia (tetracaine 0.1% and oxybuprocaine 0.4%) on central corneal thickness (CCT) values and at 2.5 mm from the corneal centre in nasal, temporal, superior and inferior hemi meridians, monitored by Orbscan over a period of 16 minutes. MATERIALS AND METHODS: The corneal thickness of 12 right eyes of 12 young healthy men was determined using the Orbscan Topography System. Values were determined at the centre and paracentral regions 2.5 mm from the centre every 2 minutes for 16 minutes before and after the administration of 1 drop of double anaesthetic Colircusi which contains tetracaine 0.1% and oxybuprocaine 0.4%. RESULTS: There was no obvious trend of central and paracentral corneal thickness value change before and after administration of Colircusi (paired ANOVA, p>0.05). Although corneal thickness variation was not statistically significant, higher differences were observed at the 6 minute time-point for CCT and at 8 minutes for nasal paracentral corneal thickness. CONCLUSIONS: One drop of double anaesthetic Colircusi with tetracaine 0.1% and oxibuprocaine 0.4% does not produce any significant change in central corneal thickness or in paracentral regions 2.5 mm from the centre (nasal, temporal, superior and inferior hemi meridians).

Lynch syndrome in colorectal cancer patients.

Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, is the most common form of hereditary colorectal cancer. It is characterized by early onset of colorectal cancer and other extracolonic-associated malignancies. This disorder is inherited in an autosomal dominant pattern and is due to a mutation in one of the DNA mismatch repair genes. Although clinical and molecular understanding of the syndrome has progressed dramatically in the last decade, diagnosis of the syndrome is still a clinical challenge. This review summarizes the main features of the syndrome and provides an update of its management.

[Corneal asphericity in a young adult population. Clinical implications]. / Asfericidad corneal en una población de adultos jóvenes. Implicaciones clínicas.

PURPOSE: To determine the relevance of the different ocular optical components in the refractive state of young adults, paying special attention to the corneal topography represented by the asphericity value. SUBJECTS AND METHODS: Corneal topographies and ultrasonic biometries were obtained from 109 university students with different refractive errors (spherical equivalent range: +3.25 D to -11.00 D). A regression study was performed in order to establish the relationships between corneal asphericity and refractive error, as well as other ocular optical components related to the emmetropization mechanism of the eye. RESULTS: The mean asphericity values were -0.23 (SD 0.08, range: -0.42 to -0.03). All the values correspond to the mathematical description of the prolate ellipse, most commonly accepted for the normal human cornea. The statistical correlation between asphericity and equivalent refractive error was not significant, but a significant correlation was found for the asphericity with respect to the radius of curvature, vitreous chamber depth and axial length. CONCLUSIONS: 1) The asphericity values support the generalised morphology of the prolate cornea as the standard. The influence of this configuration on the contact lens fit, refractive surgery or the visual performance of the eye are discussed. 2) Results suggest that, although a relationship between axial length and corneal topography actually exists, it is not likely that the latter has implications for the emmetropization mechanisms which determine the refractive state of the adult eye.

[Changes in axial length/corneal radius ratio (AL/CR) according to refractive state of the eye. Relationship with ocular components]. / Variación de la ratio longitud axial/radio corneal (LA/RC) con el estado refractivo ocular. Relación con los componentes oculares.

PURPOSE: Determination of the role of the axial length/corneal radius ratio (AL/CR) in the refractive state and investigation of its relationship with the ocular optical components: AL, CR, anterior chamber depth (ACD), crystalline lens thickness (CT) and vitreous chamber depth (VCD). METHODS: The RE (right eye) of 193 University students 22.27 (SD 3.24) years, with different refractive errors (spherical equivalent range: +3.00 D to -11.00 D), being divided into: emmetropes, hyperopes and myopes (low, moderate and high). The ACE, the CT, the VCD and the AL were measured by ultrasonography (unidimensional echography); and the mean CR by videokeratoscopy. RESULTS: The value of AL/CR obtained was 2.98 (SD 0.69) for emmetropes, 2.89 (SD 0.87) for hyperopes, 3.01 (SD 0.07) in low myopias, 3.10 (SD 0.11) in moderate myopias and 3.23 (SD 0.12) in high myopias. The AL/CR ratio showed a higher correlation with the refractive error. Besides, all the refractive groups were observed to have lower CE values as the AL/CR increased. This tendency is statistically significant in hyperopes, emmetropes and low myopes; and is not in moderate and high myopias. All the study groups could be observed to have a positive and statistically significant correlation between AL/CR and ACD. CONCLUSION: The ratio AL/CR is the most important parameter and the best predictor of the refractive state of the human eye. It provides important information on how best to determine the degree of emmetropization given by the crystalline, decreasing its power and the ACD in concordance with the LA. A value for the ratio AL/CR above 3.00 could be considered as a risk factor for the development of myopia in emmetropic eyes.

Accuracy and precision of EyeSys and Orbscan systems on calibrated spherical test surfaces.

BACKGROUND: It is important to know how well the surface topography can be measured with current devices for corneal topographic analysis. There are several applications that need an accurate and precise method to measure corneal shape and variations, such as the effect of contact lens wear and the different refractive surgery techniques. PURPOSE: The aim of this study is to compare the accuracy and reproducibility of the measurement of the central curvature on calibrated steel balls using the EyeSys videokeratoscope and the Orbscan corneal topography system. METHODS: The videokeratoscope (EyeSys Corneal Analysis System 2000, version 3.1) and the Orbscan corneal topography system (Orbscan II version 3.0) were used by four trained investigators to measure a series of five uniform and calibrated test surfaces with known radius of curvature ranging from 6.13 to 9.00 mm. RESULT: No statistically significant difference was found between the videokeratoscope and Orbscan systems in relation to accuracy or precision. The 95% confidence limits showed a close agreement between both instruments. The mean bias was less than +/-0.05 mm for both devices. The precision of the instruments was found to be similar. CONCLUSION: The EyeSys seems to measure more accurately, but the accuracy of the Orbscan was also acceptable, suggesting that both instruments are accurate and precise enough for research and clinical purposes. However, further studies of accuracy and repeatability of topographical measurements on human eyes generated by different topographers are necessary.

Comparación de la incidencia de lesiones por accidente de trabajo según la Encuesta de Población Activa y el Registro de Afiliados a la Seguridad Social / Occupational injury incidences comparisons according to the Active Workforce Survey and the Social Security System Register

Objetivos. El cálculo de la incidencia de las lesiones por accidentes de trabajo (LAT) debe basarse, idealmente, en el registro de Afiliados a la Seguridad Social (RASS), pero dada la dificultad de obtenerlo y la ausencia de variables como la ocupación, es habitual utilizar como denominador los datos de asalariados de la Encuesta de Población Activa (EPA). El objetivo de este estudio fue comparar la incidencia de LAT mortales y no mortales con baja en jornada en el año 2000, estimada con ambos denominadores. Material y métodos. Las incidencias para el RASS y la EPA se compararon según las variables de sexo, edad, comunidad autónoma y actividad económica. Para valorar la repercusión de los denominadores en la comparación de las incidencias según las variables estudiadas se utilizó la prueba de Spearman. Resultados. El número de trabajadores asalariados, fue, según la EPA, un 8 por ciento menos que el número correspondientes al RASS. La incidencia a partir de laEPA sobreestima generalmente a la calculada con el RASS, encontrando las mayores diferencias en actividades económicas como la "Agricultura, ganadería, caza y silvicultura" (69,2 por ciento), "Pesca" (38,4 por ciento), "Comercio y reparación de vehículos" (21,1 por ciento) y "Actividades inmobiliarias y alquiler de servicios" (42 por ciento). Para las restantes variables las diferencias fueron menores. El orden de magnitud en todas las comparaciones fue parecido en ambas series de incidencias, tanto en las no mortales como en las mortales. Conclusiones. La incidencia de LAT fue generalmente más elevada si se calcula a partir de los datos de la EPA que si se estima a partir de los datos del RASS, dado que los datos de la EPA utilizados se refieren a los asalariados, dejando fuera a los trabajadores dados de alta en los regímenes especiales del Mar, Agricultura y Minería del Carbón. Sin embargo, la comparación según las variables analizadas se ve poco afectada, ya que el orden de magnitud obtenido a partir de las incidencias fue parecido entre ambas series de incidencias (AU)

[Analysis of the mechanisms of minor occupational injuries in the construction industry in Spain]. / Análisis de los mecanismos de producción de las lesiones leves por accidentes de trabajo en la construcción en España.

OBJECTIVES: The construction industry produces the highest number of occupational injuries in Spain (25.6%). Of these, 98.5% were minor injuries with 5 million workdays lost in 2000. This occurred even after the recent introduction of numerous health and occupational safety regulations. The objective of the present study was to identify the specific mechanisms of minor occupational injuries in the construction sector. METHODS: In 2000, there were 235,853 minor occupational injuries in the construction industry. From these, injuries in general construction and civil engineering were selected (n = 155,044). These injuries affected both the total number of workers in the sector as well as bricklayers and unskilled construction workers. Insurance and financial activities (n = 2,019) were selected as a reference economic sector. Minor occupational injuries due to nontraumatic processes (heart attack, etc.) were taken as a control group (n = 167), assuming that the risk of nontraumatic processes was independent of economic activities. Odds ratios (OR) were adjusted by age, sex, years of work experience, type of employment and company size through nonconditional logistic regression models. RESULTS: The mechanisms with the highest risk of minor occupational lesions in construction workers as a group compared with employees in the financial sector were projection of fragments (OR = 33.0; 95% CI, 15.3-70.8) and being struck by objects (OR = 18.2; CI 95%, 9.7-34.1). These were also the most specific mechanisms of injury in the subgroup of bricklayers and unskilled construction workers. CONCLUSIONS: Activities aimed at preventing minor occupational injuries in the construction sector should be orientated towards these mechanisms, especially projection of fragments despite the low frequency of this mechanism compared with that of other mechanisms. Case-control design is a useful alternative approach for research into occupational injuries.