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PubMed2005

An anatomical and biometrical study of the femoral trochlear groove in the human fetus.

We performed a biometric analysis of the femoral trochlear groove in the fetus and compared our findings with those observed in adults. We studied 44 formalin-preserved fetuses (13-38 weeks) and used digitized images to obtain measurements (alpha angle of the groove, trochlear slopes thetaL and thetaM). A comparison of means between our series and adults was achieved. For each angle of the distal epiphysis (alpha, thetaL, thetaM) there was no significant difference between our fetal series and adults. This is the first biometric study of fetal trochlea. The morphology of the lower femur appears to be the same in the fetus and the adult.

Adult↗
PubMed1995

The metrics of cardiac chronotropism: biometric perspectives.

The selection of heart period versus heart rate as a chronotropic metric has been considered from quantitative and statistical perspectives, which have not yielded a universal preference for either metric. In the present paper, we discuss biometric considerations that bear on the selection of the optimal chronotropic metric. Biometric evidence reveals that the transfer functions relating autonomic nerve traffic to chronotropic effects on the heart are more nearly linear for heart period than for heart rate. This confers considerable advantage on heart period as a chronotropic metric and can facilitate the study of psychophysiological relationships. We further show that heart period offers greater flexibility, because heart period data can be evaluated in cardiac time units (beats) or in real-time units (s), whereas heart rate data can only be analyzed in real time. These considerations suggest clear advantages to heart period as a chronotropic metric.

Animals↗
PubMed1987

A biometric investigation of late onset myopic eyes.

There is a paucity of biometric information on late onset myopia (onset after 15-years-old). The present investigation compared the ocular component dimensions of 30 late onset myopes and 30 emmetropes, who were both age and sex matched. Measurement techniques included A-scan ultrasonography and keratometry. The findings revealed that the ultimate cause of late onset myopia is vitreous chamber elongation. Late onset myopes were also found to have significantly deeper anterior chambers and thinner crystalline lenses, no differences being found in corneal curvature measures. Possible mechanisms leading to these observed biometric differences are discussed in the light of recent findings.

Adolescent↗
PubMed2005

Distribution of ocular biometric parameters and refraction in a population-based study of Australian children.

PURPOSE: To study the distribution of spherical equivalent refraction and ocular biometric parameters in a young Australian population. METHODS: Noncontact methods were used to examine ocular dimensions and cycloplegic autorefraction in a stratified random cluster sample of year 1 Sydney school students (n = 1765), mean age 6.7 years (range, 5.5-8.4 years). Repeated measures of axial length, anterior chamber depth, and greatest and least corneal radius of curvature (CR1, CR2, respectively) were taken in each eye. Refraction was measured as the spherical equivalent. RESULTS: Mean spherical equivalent refraction in right eyes was +1.26 +/- 0.03 D (SEM; range, -4.88 to +8.58). The distribution was peaked (kurtosis 14.4) and slightly skewed to the right (skewness, 1.7). Prevalence of myopia, defined as spherical equivalent refraction < or = -0.5 D, was 1.43% (95% CI, 0.94-2.18) in the overall population. Axial length, anterior chamber depth, and corneal radii of curvature were normally distributed. The mean axial length in right eyes was 22.61 +/- 0.02 mm (SEM; range, 19.64-25.35). The mean anterior chamber depth was 3.34 +/- 0.01 mm (SEM; range, 2.14-4.06). Mean CR1 was 7.85 +/- 0.01 mm (SEM) and mean CR2 was 7.71 +/- 0.01 mm (SEM). The distribution of axial length/mean corneal radius ratio was peaked (leptokurtic) with a mean of 2.906. Mean axial length was longer, anterior chambers were deeper, and corneas were flatter in the boys. CONCLUSIONS: A peaked (leptokurtic) distribution of spherical equivalent refraction was present in this predominantly hyperopic 6-year-old population. The results also showed that ocular biometric measures were normally distributed, with statistically significant gender differences found in measurements.

Adolescent↗
PubMed1991

Rapid biometric assessment of gestational age in very low birth weight infants.

Foot length and intermamillary distance were compared to gestational age assessment using obstetrical dates, physical criteria of Ballard score and the evaluation of the anterior vascular capsule of the lens (IPM). Thirty-eight healthy and appropriate for gestational age preterm infants (30 +/- 2.4 weeks) with a birth weight of 1280 +/- 410 g were studied. Internipple distance (IM) and foot length (FL) were measured with a sliding caliper graduated in millimeters. Results were analyzed using the linear regression analysis. Obstetrical dates, physical Ballard score and IMP correlated significantly with both biometric measurements. Mean IM was 58.5 +/- 8.5 mm (range: 45 mm-89 mm) and mean FL was 60.6 +/- 7.9 mm (range: 45 mm-75 mm). The data indicate that the appropriate use of biometric parameters in the early postnatal period can be used to improve assessment of gestational age in VLBW infants.

Biometry↗
PubMed1989

Waardenburg's syndrome: a comparison of biometric indices used to diagnose lateral displacement of the inner canthi.

Clinical inspection may be sufficient to diagnose Waardenburg's syndrome Type I in most individuals but in some the presence of lateral displacement of the medial canthi may not be apparent. In such instances biometric indices are used to determine whether or not this feature is present. In this paper the discriminant ability of 7 biometric indices are examined and compared and the most efficient are identified. The results showed that indices based upon the three interocular distances: inner canthal, interpupillary and outer canthal measurements, were the more accurate indicators.

Abnormalities, Multiple↗
PubMed1981

Privacy Act of 1974; new system of records--Department of Health and Human Services. Notification of new system of records. Mental Health Epidemiologic and Biometric Research Data.

In accordance with the requirements of the Privacy Act, the Public Health Service (PHS) is publishing a notice of a proposal to initiate a new system of records in the Alcohol, Drug Abuse, and Mental Health Administration (ADAMHA), National Institute of Mental Health (NIMH), entitled, "Mental Health Epidemiologic and Biometric Research Data, HHS/ADAMHA/NIMH." The purpose of the new system will be to maintain a data base for biometric and epidemiologic research in the area of mental health and mental illness. This system will allow the statistical analysis of research data to test hypotheses about relationships among the various items of information and generate new hypotheses to guide future research.

Confidentiality↗
PubMed2000

A biometric guide to prosthetic tooth positioning investigated in subjects with Class II division 2 incisor relationships.

A biometric guide for positioning of the maxillary central incisors in complete dentures is the incisor-incisive papilla distance. This distance was compared in dentate subject with either Class I or Class II/2 incisor relations. Maxillary casts were orientated parallel to the occlusal plane on an xy table, connected to a movable vertical arm. The distance from the posterior edge of the papilla to the labial incisor surface was measured. Results showed a mean difference of 2 mm between the groups, significant at the P < or = 0.001 level, however this distance would not appear to invalidate the conventional biometric guideline of 10 mm.

Adult↗
PubMedDate not supplied

Biometric analysis of phenotypic characters of potato shoot-tips recovered from tissue culture, dimethyl sulphoxide treatment and cryopreservation.

A biometric approach partly involving principal component analysis has been used to examine the changes in phenotypic characters of shoot-tip derived potato plants recovered from tissue culture, dimethyl sulphoxide (DMSO) and cryopreservation in comparison with field-grown tuber-derived plants. There were significant differences in the quantitative characters height and tuber weight in the cryopreserved plants compared to those derived from DMSO treatment and tissue culture. These three experimental groups were shown to significantly differ from field-grown plants in the characters, tuber weight followed by height and length of petiole. The use of biometrics as an analytical approach in genetic stability assessments of plants recovered from cryopreservation to relatively small sample sizes is discussed.

Biometry↗
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↗
PubMed1975

The prediction of glaucoma from ocular biometric data. Part 2. An evaluation.

A method of glaucoma prediction from ocular biometric data has been described previously. A study was undertaken to evaluate the performance of the existing multiple regression equations (prediction systems) on data obtained from an independent sample consisting of 22 angle-closure glaucoma, 29 open angle glaucoma and 44 normal subjects. This performance, found by comparing the predicted and actual classification for this sample, was such that between 2 and 7% false positives and 12 and 27% false negatives were found on the equations differentiating glaucoma from normal subjects; and between 14 and 27% false positives, with 10 to 14% false negatives on the equations classifying the glaucoma subjects as angle-closure or open angle. From these results the efficiency of glaucoma prediction from ocular biometric data would appear to be equal to that of the combined tonography and provocative tests, provocation with corticosteroids and visual field screening.

Anthropometry↗
PubMed1992

Biometric aspects of diffractive multifocal intraocular lenses.

A retrospective biometric study was done on 132 patients with diffractive multifocal intraocular lenses. The two principal focal points induced by the intraocular lens were refracted for distance in each patient. The difference in diopters between the refractions was obtained, and the A constant (SRK formula series) and anterior chamber depth (ACD, Binkhorst formula) were calculated. Our results showed the A constant was 116.46. This value was consistent and not affected by the axial length of the eye in the 22mm to 24.5mm range. In patients who had emmetropia with the intraocular lens power implanted alone, the constant was equal to 116.3. The ACD was 3.94mm. This value was lower in shorter eyes and higher than 3.94mm in longer eyes. On the basis of the data obtained, when the SRK-II formula is used, an A constant of 116.4 should be used in preoperative biometric calculations.

Anthropometry↗
PubMed1990

The Anopheles gambiae complex in the Federal Islamic Republic of Comoros (Indian Ocean): some cytogenetic and biometric data.

Samples of adult females of the Anopheles gambiae complex from thirteen localities of three islands of the Comoro Archipelago (Anjouan, Grande Comore and Moheli) were identified by analysis of ovarian polytene chromosomes as An. gambiae s.s. The samples showed only the inversion polymorphism 2La, the mean frequency of the inverted arrangement being 38%. A significantly higher frequency of the inverted arrangement 2La was observed in the localities with a lower annual rainfall. Similarities between the chromosomal polymorphism of the samples from Comoros and that of coastal eastern African countries suggest a probable continental origin of the An. gambiae s.s. populations in the Comoro Archipelago. A biometric analysis was carried out on the palpal index and the number of coeloconic sensilla, two characters partially diagnostic between fresh- and salt-water members of the gambiae complex. The palpal index of the 2La homozygous inverted females of An. gambiae s.s. was found to be significantly higher than the index of standard homozygotes and heterozygotes, suggesting a relation between the inversion and this biometric character. No An. merus was identified, although larvae of An. gambiae s.l. were observed breeding in brackish water.

Animals↗
PubMed1983

A biometrical analysis of perceptions of family environment: a study of twin and singleton sibling kinships.

Biometrical genetic analysis was applied to sibling and twin kinship data on 2 dimensions of perceived home environment. Correlations on 1 dimension, Restrictiveness-Permissiveness, were equal and significant for all kinships: MZ twins, DZ twins, same-sex siblings, and opposite-sex siblings significant for all 4 kinships: MZ twins, DZ twins, same-sex siblings, and opposite-sex siblings (r greater than .40). An E2-E1 biometrical model fitted Restrictiveness-Permissiveness, implying that treatments common to siblings create agreement about perceived environment. As intrapair differences were the same for all 4 kinships under this model, the equal environments assumption of the twin method was supported. In contrast, the Acceptance-Rejection dimension fitted a G-E1 model that makes the assumption that sibling similarity is the result of genetic factors and postulates an absence of shared environmental influences. This finding suggests that this aspect of home environment may depend as much on the child's inherited traits as on actual treatments and is in accord with the genetic analysis of individual traits in that developmentally effective environmental factors do not appear to be common to siblings.

Environment↗
PubMed1995

[Prevalence of E. multilocularis in foxes in Styria taking into consideration biometrical methods].

The results of a survey covering whole of Styria/Austria, which was based on a biometrical sampling plan, showed the prevalence rate of E. multilocularis among foxes to be 3.6% (18 out of 500 examined foxes). There is however a significant regional difference in the prevalence rate. All 18 infected foxes were found in the North-West of Styria, which results in an estimated proportion of 9% in this region. The study could not reveal any significant difference between male and female foxes concerning the infection rate. The age distribution was 67 percent juvenile foxes (< 1 year) to 33 percent adults. The biometrical methods enable us to determine an exact spatial spread of the parasite and thus makes it possible to find out any potential risk for the population.

Aging↗
PubMedDate not supplied

[Biometrical analysis in the radiobiology works of N. V. Luchnik].

The contribution of the famous Russian geneticist and biophysicist N. V. Luchnik into biometrical analysis of radiobiological data is discussed. His works on radiation mortality of mice and the process of post-radiation repair of chromosome aberrations are thoroughly observed. The conclusion of necessity to develop biometrical analysis as separate part of biometry is made.

Animals↗
PubMed1977

The impact of breast feeding patterns on the biometric analysis of infant mortality.

A major assumption of the biometric analysis of infant mortality as developed by Bourgeois-Pichat is that the age structure of infant deaths after the first month of life is virtually constant across time and cultures. Reanalysis of results from studies which compare the mortality of infants according to the type of feeding indicated that the relationship between mortality and age within the first year of life followed different patterns for breast fed and artificially fed infants. Historical data for populations with different breast feeding customs reveal similar differences in the age pattern of infant mortality. In populations where breast feeding was uncommon or of very short duration, infant mortality rises particularly steeply during the early months of the first year of life. The age structure of infant mortality in less developed countries where breast feeding is decreasing rapidly may bsimilarly affected. When substantial deviations from the linear relationship are evident, particular caution is required in applying the biometric technique, since in such situations the estimated endogenous mortality is very much affected by the particular set of data points within the first year of life which are chosen for the basis of the estimates.

Age Factors↗
PubMed1998

Biometric confirmation of the Hirschberg ratio in strabismic children.

PURPOSE: In the Hirschberg eye position test, the ratio of strabismic angle to decentration of the corneal reflex is dependent on two biometric parameters of the eye: the radius of the corneal curvature and the depth of the anterior chamber. This study was designed to confirm whether the Hirschberg conversion ratio (HR) previously determined for adults can be used for children of various ages despite structural growth of the eye. METHODS: For 262 eyes of 131 children with strabismus (age range, 6 months to 11 years), the radius of the corneal curvature was measured with an auto-keratometer and the anterior chamber depth with an A-scan ultrasound unit under general anesthesia before the surgery. Using these measurements, the HR was computed on the basis of a geometric model. RESULTS: The calculated HR was constant across the age range, and the mean+/-SD was 19.9+/-1.9 prism diopters/mm (95% confidence interval, 16.1-23.6 prism diopters/mm). The ratios for the two eyes in each subject showed good correlation (R = 0.854, P = 0.0001). Neither of the biometric measurements was significantly correlated with age, although considerable scatter of the measurements was observed. CONCLUSIONS: These results indicate that the averaged HR can be applied in children regardless of the patient's age, although intersubject variance of the ratio should be taken into account.

Anterior Chamber↗