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At least 757 records · Page 42Linked to original sources

PubMed2006

Distribution of optic disc parameters measured by OCT: findings from a population-based study of 6-year-old Australian children.

PURPOSE: To study the distribution of optic disc, cup, and neural rim size by ocular and demographic variables in a population-based sample of 6-year-old children. METHODS: The Sydney Childhood Eye Study examined 1765 of 2238 eligible 6-year-old children (78.9%) from 34 randomly selected Sydney schools during 2003 to 2004. Comprehensive standardized eye examination included cycloplegic autorefraction, optical biometry and "fast optic disc" scans performed using optical coherence tomography. RESULTS: Scans of adequate quality were available for 1309 children (75% of participants), with 70% aged 6 years; 50.9% were boys. Mean (+/- SD) horizontal and vertical disc diameter and disc area was 1.53 +/- 0.21 mm, 1.79 +/- 0.28 mm, and 2.20 +/- 0.39 mm(2), respectively. Corresponding cup dimensions were 0.70 +/- 0.28 mm, 0.73 +/- 0.27 mm, and 0.48 +/- 0.32 mm(2). A definable optic cup was absent in 7.4%, 87% of whom were European white. Cup-to-disc diameter ratios were 0.46 +/- 0.16 horizontally and 0.42 +/- 0.15 vertically, whereas cup-to-disc area ratio was 0.22 +/- 0.13. Mean +/- SD neural rim area was 1.76 +/- 0.44 mm(2) and increased with disc size (Pearson correlation = 0.68, P < 0.0001). Horizontal and vertical average nerve widths were 0.36 +/- 0.05 and 0.28 +/- 0.05 mm, respectively. In analyses adjusting for potential confounders, disc area increased significantly with axial length (P(trend) < 0.0001) and refraction (P(trend) = 0.02). Rim area increased only with axial length (P(trend) = 0.01). There were no gender differences, except for average nerve width, marginally greater in boys. Most disc and cup dimensions were significantly larger in East-Asian than European white and Middle Eastern children. CONCLUSIONS: Disc, cup, and neural rim parameters were generally normally distributed in this young population. Axial length appeared to be a stronger determinant of disc and rim size than refraction. Some ethnic but not gender differences were demonstrated for most parameters.

Australia↗

PubMed2005

[Refraction study on pseudophakic children].

PURPOSE: To verify the refractive alterations in eyes of children submitted to surgery with implant of intraocular lens (IOL) and to investigate prediction of biometry in these cases. METHODS: Thirty-three eyes were studied with previous measurement of visual acuity with indication for cataract surgery with implant of intraocular lens in the Outpatient Clinic of Congenital Cataract of the Federal of University of São Paulo/Paulista School of Medicine, (UNIFESP-EPM) from January, 1998 to December, 2000. After the surgery, refraction, prescription of glasses with appropriate treatment for visual stimulation of the children, and measurement of the final corrected visual acuity were performed. Final refraction, biometric accuracy and possible error factors were analyzed. RESULTS: Thirty-three surgeries in 29 children were performed. Mean follow-up time was 10.15 months ranging from 2 to 34 +/- 8.18 months. In 43% of the cases a vision equal to or greater than 20/50 was obtained. Forty-six percent of the patients presented a final refraction between +1.00 and -1.00 spherical diopters. CONCLUSION: Treatment of congenital cataract through implant of intraocular lens continues to be controversial, where long-term results are not known. A great number of patients were operated on at a late time and progressed with amblyopia and low visual acuity even after treatment with difficult access to early and adequate treatment. In spite of residual refraction the patients obtained good visual acuity. Twenty-one percent of the cases with refractive alteration with hyperopia will still have increase in their axial diameter and consequently myopia with reduction of their refraction.

Adolescent↗

PubMedDate not supplied

[Curve of normal fetal weight values estimated by ultrasound according to gestation age].

OBJECTIVE: to evaluate the evolution of estimated fetal weight in normal pregnancies in Campinas, Brazil, between 20 to 42 weeks. DESIGN AND METHODS: A descriptive study was performed, including 2,874 normal pregnant women studied through routine obstetric ultrasound with fetal biometry, using the Hadlock (1991) formula for fetal weight estimation. Data were evaluated by fitting a curve with the 10th, 50th, and 90th percentiles of fetal weight for gestational age, subsequently submitted to a smoothing procedure by quadratic polynomial adjustment. RESULTS: the 50th percentile was 368g at 20th week, 1,512g at 30th, and 3,417g at 42nd week. There was a mean weight increase of 200g per week from the 27th to 38th week, when the gain decreased. CONCLUSIONS: The availability of a Brazilian curve of normal estimated fetal weight will allow for prenatal ultrasound diagnosis of deviations.

Biometry↗

PubMed2006

Physiological rates in different classes of sizes of Perna perna (Linnaeus, 1758) submitted to experimental laboratory conditions.

Physiological studies of the mussel Perna perna in Brazil are almost 30 years behind those of other, more exhaustively investigated species, such as Mytilus edulis. Little is known about the variations in physiological rates due to size and the consequences of maintaining P. perna in laboratory conditions. This work investigated the variations in respiration, clearance, excretion and absorption efficiency rates of P. perna, classified by size and acclimatized in a laboratory, monitoring the mussels respiration rates and biometry over a period of 30 days, in laboratory conditions. The respiration, clearance and excretion rates presented an allometric relation with the dry weight of the organisms, with b values of 0.66, 0.48 and 0.91 respectively. On the other hand, these same rates, when considered by weight (specific rates) showed a relationship that was inverse to the size of the organisms. Only the absorption efficiency was independent of the weight of the mussel. In terms of acclimatization, it was observed that it takes 10 days for the respiration rate of the mussel P. perna to stabilize in laboratory conditions, after which it follows a routine metabolism.

Absorption↗

PubMedDate not supplied

Construction of age-related reference limits for 24-h blood pressure pattern.

Blood pressure (BP) is recursively variable during the day-night cycle because of a physiological circadian rhythm. The aim of this study is, therefore, to show how to construct the population reference limits (desms) for BP in its time varying 24-h pattern, starting from a small sample, in order to facilitate their use in a local context. The sample for standardization comprised 427 clinically healthy subjects (211 males and 216 females), ranging in age from 16 to 100 years, attending their routine activities. The procedure begins with the statistical biometry related to the sample, and proceeds with the computation of the BP desms related to (1) the time-qualified discrete values; (2) the parameters of circadian rhythm; (3) the daily pressure load. The pertaining rules are explained step by stop, allowing each one to prepare the proper local desms for BP 24-h pattern. These standards may be useful for validating the individual BP monitoring according to the upper limits of the circadian physiological variability in the diagnostic procedure for identifying hypertensive subjects.

Adolescent↗

PubMedDate not supplied

Geometric ray tracing analysis of visual acuity after laser in situ keratomileusis.

PURPOSE: Using a geometric ray tracing model, we explain the increase in visual acuity observed in myopic patients after laser in situ keratomileusis (LASIK). METHODS: This study included 37 eyes of 23 patients who underwent LASIK. All patients had myopia and a spectacle-corrected visual acuity of 0.95 or worse. Clinical tests included biometry, corneal topography, pachymetry, and refraction (with and without cycloplegia). Calculations were made by tracing rays through all the refractive surfaces of the eye based on a Le Grand-type theoretical model of the whole eye. RESULTS: Comparison of spectacle-corrected visual acuity of the eye before surgery, the size of the blur circle calculated by ray tracing, and the magnification for the ocular system facilitated a numerical criterion to assess visual acuity by geometric calculation. This criterion was applied to myopic eyes that underwent LASIK, and the maximum increase in spectacle-corrected visual acuity was predicted. An actual increase in visual acuity of approximately 40% of the predicted maximum was observed in patients. CONCLUSIONS: With geometric ray tracing, it was possible not only to obtain an estimate of the visual acuity before LASIK but also to assess the value of the maximum and probable increases in visual acuity after LASIK.

Adult↗

PubMed2003

Combined sonographic and biochemical markers for Down syndrome screening.

OBJECTIVE: To evaluate the efficacy of fetal nuchal fold thickness and proximal long bone biometric measurements in modifying Down syndrome serum screening risk in a population of women referred for second-trimester sonography. METHODS: Sonographic biometric measurements and biochemical markers were combined retrospectively for 2533 women with known pregnancy outcomes. Four different screening methods were compared: (1) advanced maternal age; (2) biochemical serum screening markers; (3) modification of serum screening risks on the basis of categorical cutoffs for nuchal fold and femur and humerus length; and (4) a combined approach in which the sonographic measurements were treated as multiples of the medians and entered, together with the serum screening results, into a multivariable algorithm. The efficacy was compared at second-trimester risk cutoffs of 1:270 and 1:100. RESULTS: Down syndrome was present in 30 of the 2533 pregnancies (1 in 84). With the use of the 1:270 cutoff, biochemical screening had 93% sensitivity and a 40% false-positive rate. With application of the categorical method of fixed cutoffs to incorporate fetal biometry, the false-positive rate was reduced to 33% with no loss of sensitivity. The combined model had 83% sensitivity and a 19% false-positive rate. The combined method had the highest positive predictive value (1 in 20). Similar gains in efficacy could be shown with the 1:100 cutoff. CONCLUSIONS: For this high-risk group, the multivariate model that combines serum screening and sonography can result in a substantial reduction in the number of amniocenteses. Although the addition of the sonographic biometric measurements resulted in some Down syndrome cases being missed, the net effect was a large improvement in the overall positive predictive value of the screening.

Adult↗

PubMed1976

[Stages of development and growth of the thyroid gland and adenohypophysis of the dogfish embryo (Scillium canicula Cuv.), a chondrichthyan fish].

The thyroid morphology, histology, biometry and its anatomical connections are studied during the whole embryonic life in the small spotted dogfish (Scyllium canicula Cuv.). The first differentiation of the gland appears as a thickening of the pharyngeal floor, containing PAS inclusions, at stage 10 mm. The first follicles are apparent at stage 30 mm. The thyroid volumetric relative growth is studied during the whole development and is compared with the absolute embryonic length growth. Volumetric variations of the hypophysis upper parts and ventral lobe are also studied during the whole embryonic life.

Animals↗

PubMed2000

Sonographic measurements of subcutaneous fetal fat in pregnancies complicated by gestational diabetes and in normal pregnancies.

AIM: To compare sonographic measurements of fetal fat tissue in pregnancies complicated by gestational diabetes (GD), with patients undergoing either a diet only or a combined diet and insulin treatment, to those obtained in pregnancies with a normal glucose challenge test. METHODS: Forty-five singleton pregnancies complicated by GD but free of any other maternal disease known to affect fetal growth were recruited. GD was diagnosed by a 3-hour OGTT, and treatment was differentiated according to the glycemic profile. GD mothers were divided into two treatment groups: glycemic profile normalized by diet only treatment (n=16) and by combined diet and insulin treatment (n=29). Fetal biometry and subcutaneous fat tissue thickness of the anterior abdominal wall were sonographically evaluated at the time of diagnosis and every 4 weeks afterwards in both GD and normal glucose challenge test group (n=25). RESULTS: No differences were found in neonatal outcomes between combined diet and insulin treatment group and normal cases, whereas neonatal weight showed a statistically significant difference between diet only treatment group and healthy population. Abdominal circumference in fetuses from GD mothers and normal fetuses was similar, but there was a difference in the fetal fat tissue thickness at the time of diagnosis. CONCLUSION: Increased fetal fat tissue thickness in GD mothers at recruitment and its growth rate reduction during adequate treatment may be a new criterion for direct estimation of fetal metabolic status instead of the traditional indirect evaluation based on maternal glucose concentrations.

Adipose Tissue↗

PubMed2001

The relationship between ocular dimensions and refraction with adult stature: the Tanjong Pagar Survey.

PURPOSE: To describe the association of ocular dimensions and refraction with adult stature. METHODS: This was a population-based cross-sectional survey of adult Chinese aged 40 to 81 years residing in the Tanjong Pagar district in SINGAPORE: As part of the examination, ocular dimensions, including axial length, anterior chamber depth, lens thickness, and vitreous chamber depth, were measured using an A-mode ultrasound device. Corneal radius and refraction were determined with an autorefractor, with refraction further refined subjectively. Height (in meters) and weight (in kilograms) were measured using a standardized protocol, and body mass index (BMI) was calculated as weight divided by the square of the height (kilograms per square meter). RESULTS: Data on ocular biometry, refraction, height, and weight were available on 951 (55.4%) participants with phakic eyes. After controlling for age, sex, education, occupation, housing type, income, and weight, it was found that taller persons were more likely to have longer axial lengths (+0.23 mm longer axial length, for every 0.10 m difference in height), deeper anterior chambers (+0.07 mm), thinner lenses (-0.09 mm), longer vitreous chambers (+0.26 mm), and flatter corneas (+0.09 mm longer corneal radius), although refractions were similar. In contrast, heavier persons tended to have more hyperopic refractions (+0.22 D for every 10 kg difference in weight, +0.56 D for every 10 kg/m(2) difference in BMI) but similar ocular dimensions. CONCLUSIONS: Adult height is independently related to ocular dimensions, but does not appear to influence refraction. Thus, although taller persons are more likely to have longer globes, they also tend to have deeper anterior chambers, thinner lenses, and flatter corneas. Conversely, weight is independently related to refraction, although the exact biometric component responsible for this association is not apparent.

Adult↗

PubMed2001

Information processing in healthcare at the start of the third Millennium: potential and limitations.

The 21st century is said to be a century of the information society. We should be aware that continuing progress in information processing methodology (IPM) and information and communication technology (ICT) is changing our societies, including medicine and health care. At the start of the third Millennium we should ask ourselves, what progress can we expect from modern IPM/ICT for healthcare in the coming decade, what concerns does the information society have to face, and what steps have to be taken. These questions were addressed by clinicians, researchers and industrial representatives in a panel discussion at the joint conference ISCB-GMDS-99 of the International Society of Clinical Biostatistics and the German Society for Medical Informatics, Biometry and Epidemiology. Important aspects raised by the panelists and in the subsequent discussion were: (1) the main goal of expanding IPM/ICT should be to further improve quality of care, while maintaining reasonable costs; (2) with the support of modern IPM and ICT the boundaries between inpatient and outpatient care will fade away enabling a more efficient, patient-centered health care; (3) cooperation between health-care professionals will increase; there will be different ways of communication between them and with the patient, including modern ICT and the Internet; (4) society must be concerned with achieving equal opportunities in being informed about and in using new ICT; (5) misuse of data will remain a serious problem and can become an obstacle to progress.

Biometry↗

PubMed2001

Diagnosis of canine fetal health by ultrasonography.

The detection of fetal pathology is important for the care of puppies in the postnatal period. The objective of this study was to identify parameters of fetal distress by determining fetal heart rate and bowel movements, and also to detect early pathology by means of fetal biometry, which involves determination of the biparietal and abdominal diameters. Ultrasonographic examinations were carried out on 30 pregnant bitches of different breeds and ages at least three times, including examination at days 40-47, days 48-57, and days 58-62 after coitus, and subsequently every 12-14 h for 3 days before parturition. Fetuses that had biparietal:abdominal diameter ratios of < 2 at the second and third series of ultrasonography, or after birth were considered to have intrauterine growth retardation. The average weight of each litter was calculated and puppies that weighed < 20% of the average weight were also considered to have experienced intrauterine growth retardation. Intrauterine growth retardation occurred in 39.6% of the bitches studied. Fetuses were considered to be normal when heart rate, determined by a Doppler flowmeter was > 220 beats min-1; suffering from slight fetal distress when heart rate was between 180 and 220 beats min-1; suffering from severe fetal distress when heart rate was < 180 beats min-1. Some level of distress was observed in 33.0% of puppies. In 86.7% of bitches, bowel movements were observed in at least one puppy, and appeared to be correlated with fetal distress. Bowel movements were observed in all of the puppies that had severe fetal distress (heart rate < 180 beats min-1), whereas bowel movements were observed in only 40.0% of puppies with slight fetal distress (heart rate 180-200 beats min-1). In conclusion, ultrasonographic evaluation allowed identification of fetuses with intrauterine growth retardation, and bowel movements were a reliable indicator of fetal distress; these conditions are presumed to indicate a greater perinatal risk.

Animals↗

PubMed2002

Nearwork in early-onset myopia.

PURPOSE: To determine the relationship of nearwork and myopia in young elementary school-age children in Singapore. METHODS: A cross-sectional study of 1005 school children aged 7 to 9 years was conducted in two schools in Singapore. Cycloplegic autorefraction, keratometry, and biometry measurements were performed. In addition, the parents completed a detailed questionnaire on nearwork activity (books read per week, reading in hours per day and diopter hours [addition of three times reading, two times computer use, and two times video games use in hours per day]). Other risk factors, such as parental myopia, socioeconomic status, and light exposure history, were assessed. RESULTS: In addition to socioeconomic factors, several nearwork indices were associated with myopia in these young children. The multivariate adjusted odds ratio of higher myopia (at least -3.0 D) for children who read more than two books per week was 3.05 (95% confidence interval [CI], 1.80-5.18). However, the odds ratios of higher myopia for children who read more than 2 hours per day or with more than 8 diopter hours (1.50; 95% CI, 0.87-2.55 and 1.04; 95% CI, 0.61-1.78, respectively) were not significant, after controlling for several factors. CONCLUSIONS: Children aged 7 to 9 years with a greater current reading exposure were more likely to be myopic. This association of reading and myopia in a young age cohort was greater than the strength of the reading association generally found in older myopic subjects. Whether these results identify an association of early-onset myopia with nearwork activity or other potentially confounding factors is discussed.

Age Distribution↗

PubMed2001

[Biometric variation of the ocular globe in myopia].

GOAL: The study of correlation between myopia's pathogen and the biometrics variations of the different eye ball segments. MATERIAL AND METHOD: 64 patients were included in this study: 54 patients with myopia higher than--5 diopter and 10 patients with cataracta. All patients underwent a complete ocular examination including: visual acuity determination, ocular fundus examination, automatic refractometry, keratometry. Biometry was performed with an ultra-scan system. RESULTS: From 64 patients, 53 were with axial myopia, 1 with myopia induced by low corneal curvature radius and 10 patients with myopia induced by a high refractive index of the lens caused by cataract. In cases with axial myopia the axial length was high (26.1 mm) with a high vitreous length (20.78 mm). In cases with index myopia, only the lens thickness and the anterior chamber depth undergo biometrics variations. Curvature myopia is the result of the decrease of the corneal curvature radius. CONCLUSIONS: Axial myopia is that by far the most frequently form of myopia. In this case the increases in axial length is proportionally with the degree of myopia. Index myopia is produced by the increase of the refractive index of the lens in cataract. A low corneal curvature radius less frequently than the others produces curvature myopia.

Adolescent↗

PubMed2004

[Guidelines for writing biomedical articles containing statistical figures and analysis].

Some advices are provided in order to make statistical figures and analyses more correct in biomedical articles. The sample size has an outstanding significance. Analysing different statistical relationships the requirements of biometry should be fulfilled (number and distribution of data etc.) and interpretation of statistical findings could be done only within the domain of minimal and maximal values of independent variable. Extrapolation is not recommended due to the specific nature of the biomedical system. In some cases laboratory data should be transformed mathematically and the results of subsequent statistical calculations should be retransformed back into the biomedical system.

Biometry↗

PubMed2000

[Somatic production of two species: Crassostrea virginica and Ischadium recurvum Bivalvia in Mecoacán, Tabasco, México].

The Mexican oyster fishery, 90% supported by the coastal lagoons of the Gulf of Mexico, has decreased drastically in the last six years as a result of anthropogenic pollution and improper management. The mussel Ischadium recurvum has proliferated and competes with oysters for space and probably food. Crassostrea virginica and Ischadium recurvum were studied to evaluate somatic production with biometry and physiological condition indices (PCI's) during an annual cycle. A random sample of 200 organisms was taken montly for each species. Condition indices wet flesh weigth: wet shell weight ratio (WFW/WSW), dry flesh weight: wet flesh weight ratio (DFW/WFW), dry flesh wet: dry shell weight ratio (DFW/DSW), and ash free dry weight: tissue dry weight (AFDW/TDW) were calculated. In order to stablish physiological condition and temporal variability, these indices were compared between species and months. The somatic production of mussels was higher than in oysters. This enhancement in production could be explained by: 1) Mussel uses less energy for shell production, 2) a constant recruitment of mussel almost year-round, and 3) the mesohalin lagoon was more favourable to the mussel.

Animals↗

PubMed2000

[Eclossion of cysts of two species of Dendrocephalus (Anostraca: Thamnocephalidae) of potential use as food in aquaculture].

The use of Artemia salina nauplii as live food has significantly aided culture of commercial fish and shrimps in recent years. However, reported deficiencies in the nutritional value of some strains originated the study of freshwater fairy shrimps as an alternative to Artemia. This study presents cyst biometry for Dendrocephalus geayi and D. spartaenovae (Anostraca: Thamnocephalidae), and the effects of some physicochemical variables on cyst hatching. The biometric characteristics of D. geayi and D. spartaenovae are within the size range of commercial Artemia strains. Favorable conditions to hatch D. geayi are 30 degrees C and conductivity near that of distilled water (<5 micromhos). For D. spartaenovae, these conditions are 28 degrees C and 280 micromhos. A very low salinity such as 1 per thousand inhibits hatching in both species.

Animal Feed↗

PubMedDate not supplied

Anatomic study of femoral patellar groove in fetus.

The authors performed a biometric analysis of the femoral patellar groove in fetus and compared their findings with those observed in adults. Forty-four formalin-preserved fetuses were studied (13-38 weeks). Digitalized images were used to obtain measurements (alpha angle of the groove, trochlear slopes thetaL and thetaM). A comparison of means of independent samples between our series and adults was performed. For each angle of the distal epiphysis (alpha, thetaL, thetaM) there was no significant difference between this fetal series and adults. This is the first biometry of the fetal patellar groove. The morphology of the lower femur appears to be the same in fetus and adults. The results of this study suggest that the anatomic characteristics of the patellar groove could have been integrated into the genome during the course of evolution. This would be in favor of a genetic origin of patellar groove dysplasia.

Adult↗