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PubMed1982

Experiences with an interactive computer program for recording biometrical health screening data.

The nurses' measurements of biometrical health screening data comprise the central elements in our multiphasic preventive medical investigation in Malmö. It is also vitally important for the information processing, evaluation and actions of the screening that all test values and other data can be supplied to a uniform computer bank without delay in terms of secondary transferral routines. In our ongoing population investigation projectin Malmö, this has been accomplished by on-line computer programs for the different components of the screening. Here we describe the practical experiences with the subroutine use by the nurses to feed the biometrical test results to the computer bank.

Biometry↗
PubMed1990

Biometric variables in patients with occludable anterior chamber angles.

Biometric studies of the ocular dimensions in eyes with narrow anterior chamber angles provide insight into the pathophysiology of pupillary block and may show which eyes are more prone to develop angle-closure glaucoma. We reviewed the records of 56 patients with occludable angles examined between 1980 and 1984. Initial biometric data obtained on the patients included corneal diameter, anterior chamber depth, lens thickness, and ocular axial length. The average length of follow-up was five years. Of 54 patients with complete clinical records, 20 (37%) eventually required peripheral iridectomy after a mean duration of 16 months from the initial examination. Cox's survival analysis showed a strong correlation between shortened duration to peripheral iridectomy and increasing lens thickness/ocular axial length ratio factor (P = .03). No other variables were significantly related to outcome. This suggests that the lens thickness/ocular axial length ratio may be useful as a predictor of clinical outcome in narrow-angle glaucoma.

Anterior Chamber↗
PubMed2002

Biometrical genetics.

Biometrical genetics is the science concerned with the inheritance of quantitative traits. In this review we discuss how the analytical methods of biometrical genetics are based upon simple Mendelian principles. We demonstrate how the phenotypic covariance between related individuals provides information on the relative importance of genetic and environmental factors influencing that trait, and how factors such as assortative mating, gene-environment correlation and genotype-environment interaction complicate such interpretations. Twin and adoption studies are discussed as well as their assumptions and limitations. Structural equation modeling (SEM) is introduced and we illustrate how this approach may be applied to genetic problems. In particular, we show how SEM can be used to address complicated issues such as analyzing the causes of correlation between traits or determining the direction of causation (DOC) between variables.

Biometry↗
PubMed2000

Fetal biometric parameters, twin type and birth weight difference. A longitudinal study.

OBJECTIVE: To examine the relationship between twin type, divided by zygosity, chorionicity, and birth weight difference [more or less than 15% intertwin weight difference at delivery] on fetal biometric measurements, including biparietal diameter, transverse abdominal diameter, head and abdominal circumferences (AC) and head and abdominal areas, femur length (FL), transverse cerebellar diameter, cerebellar circumference and cerebellar area at 18, 23, 28 and 32 weeks of gestational age. STUDY DESIGN: A prospective and longitudinal study was done on 75 twin pairs that did not present the twin-twin transfusion syndrome (150 fetuses) divided into birth weight difference group I (<15%) and group II (>/=15%). The twin pairs were divided into three groups: dizygotic, monochorionic, and dichorionic-monozygotic. In each group the differences in various ultrasound indices were evaluated in reference to discordant growth or concordant growth. RESULTS: In our sample, there were no monozygotic twin pairs with dichorionic placentation with a birth weight difference of more than 15%. Significant associations of group and gestational age were found in dizygotic and monochorionic twins. Intrapair differences were significantly higher in group II (>/=15%) than in group I (<15%) for all fetal parameters studied except for AC, abdominal area and all cerebellar parameters. The value of these discrepancies increased according to gestational age except for FL. Significant interactions between group and zygosity type indicated that intrapair FL differences were more associated with group in monochorionic twins, whereas intrapair transverse cerebellar diameter differences were more associated with group in dizygotic twins. CONCLUSION: Our data show that most fetal biometric parameters are associated with birth weight discordancy. Abdominal area could be a relevant marker for twins with obstetric complications. Note that this is the first research that has studied a twin sample divided by both twin type and birth weight group.

Biometry↗
PubMed2002

References intervals for fetal biometrical parameters.

OBJECTIVE: To establish normal reference intervals for biparietal diameter, head circumference, abdominal circumference, and length of femur, a cross-sectional study. STUDY DESIGN: Five hundred singleton fetuses for each week at gestations between 23 and 41 weeks with a total of 9500 fetuses. Antenatal ultrasound measurements from all consecutive pregnant women referred to the ultrasound unit for scanning of fetal condition are prospectively entered in a data bank. For the purpose of this study, sonographic measurements were collected retrospectively and each fetus contributed just one value to the reference sample. RESULTS: The mean curve of the four biometrical parameters varied with gestational age, with flattening of the curves at the end of gestation and increased width of normal ranges with increasing gestational age. Maximal weekly increases occurred at 24 weeks' gestation for head circumference, abdominal circumference, and length of femur and at 26 weeks' gestation for biparietal diameter. The four biometrical parameters, however, showed 50% increases in size at 33 weeks' gestation. CONCLUSIONS: These fetal size reference intervals are clinically relevant and can be used for populations with epidemiological features and distribution of neonatal birth weights similar to our data.

Abdomen↗
PubMed2003

The effects of the chorda tympani damage on submandibular glands: biometric changes.

OBJECTIVE: It was aimed to analyze the biometric changes in ipsilateral submandibular glands of patients with unilateral chorda tympani (ChT) section during otological operations, compared with change in size of the contralateral glands and with those of healthy subjects. METHODS: 29 patients with unilateral complete ChT section and 29 healthy subjects with identical ages, genders, and weights to the patient group were examined ultrasonographically. The patients having a mean duration to follow-up examination of 32 months (2-84 months) were subdivided into two groups by their time to follow-up as short-term patient group (2-12 months, 14 patients) and long-term patient group (13-84 months, 15 patients). The ultrasonographic dimensions and volumes of submandibular glands were compared statistically between the groups. RESULTS: In the patient group, the glands on the contralateral, non-operated side were found to be greater than the ipsilateral, denervated glands in terms of both paramandibular depth dimension (P<0.05) and volume (P<0.01). The differences could be determined only in long-term patient group. When comparing the submandibular glands of the patient group with those of the control group, it was found that paramandibular depth dimension and volume of the submandibular glands on the contralateral, non-operated side were statistically greater (P<0.01). There was no difference between submandibular glands on the operated side of the patient group and those of the control group (P>0.05). CONCLUSION: The late (13-84 months) biometric results of ChT damage on submandibular gland were significant for increase in the size of the contralateral, non-denervated submandibular gland. An atrophying effect was not ascertained in the submandibular glands denervated parasympathetically due to the section of the ChT.

Adolescent↗
PubMed1996

Effects of buccal shields on the maxillary dentoalveolar structures and the midpalatal suture--histologic and biometric studies in rabbits.

The mechanism of the buccal shields with regard to regulating the transversal relationship of the maxillary dental arch is uncertain. The periosteal pull theory, growth at the midpalatal suture and changes in equilibrium have all been proposed as explanatory factors. The aim of the study was to investigate the transversal development of the dental arch and the osseous remodeling at the lateral surfaces of the maxillary alveolar process and in the midpalatal suture after stretching the bucca (cheek) with buccal shields in the vestibulum. Ten New Zealand white male rabbits 12 weeks old were used. The animals were divided into two groups (control and experimental). Initial and final impression had been taken from the two groups and plaster models were made using biometric analysis in all animals of each group. Transversal measurements were taken of the distances between the maxillary right and left teeth. Tetracycline hydrochloride and Alizarin complexone were used to label the mineralizing tissues. After the animals had been killed, the biopsies from the midpalatal suture, the alveolar wall, and the periosteum were studied under a microscope. The results from the biometric analysis showed maxillary dental arch expansion in the two groups that was significantly larger in the experimental group. Microscopically, the growth at the midpalatal suture was also significantly larger in the experimental group, while no significant differences were found at the maxillary alveolar bone in the two groups. The conclusions drawn from this study are that the vestibular buccal shields bring about an increased expansion of the maxillary dental arch and increased growth at the midpalatal suture. No increased bone deposition was found at the buccal dentoalveolar wall, inducing doubts as to the accuracy of the periosteal pull theory for widening of the dental arch.

Activator Appliances↗
PubMed2002

Atherina punctata and Atherina lagunae (Pisces, Atherinidae), new species in the Mediterranean Sea. 1. Biometric investigations of three Atherinid species.

Discriminative canonical analysis of 87 biometric parameters in the marine and lagoon atherinids of 'Atherina boyeri' complex from the Mediterranean Sea helps defining three distinct atherinid groups: marine punctuated, marine unpunctuated and lagoon atherinids. Each atherinid group constitutes a clearly independent original entity. Besides, each one is a more or less heterogeneous group with geographical disparities, characterising specimen collected from France and Tunisia. Concordance of biometric, biochemical and genetic results as well help define two new species of atherinids: Atherina punctata = punctuated marine atherinids, and Atherina lagunae = atherinids living in lagoon environments.

Animals↗
PubMed1999

The comparison of cyclopentolate and atropine in patients with refractive accommodative esotropia by means of retinoscopy, autorefractometry and biometric lens thickness.

PURPOSE: In this study, we aimed to compare the cycloplegic effect of cyclopentolate HCI 1% and atropine sulphate 1% in patients with refractive accommodative esotropia by means of retinoscopy, autorefractometer and the measurement of lens thickness by biometry. METHODS: Thirty-two patients with refractive accommodative esotropia aged from 5 to 10 (mean 6.8+/-1.4), had a deviation under 10 prism diopters, and underwent retinoscopic, autorefractometric and biometric study in dry and wet conditions. RESULTS: The retinoscopic, autorefractometric and biometric findings of the right eye were 5.10+/-1.21 diopter (D), 5.03+/-1.20 D, 3.43+/-0.16 mm with cyclopentolate, and 5.2+/-1.2 D, 5.2+/-1.2 D, 3.4+/-0.1 mm with atropine. In the left eye, the measurements were 5.2+/-1.4 D, 5.1+/-1.4 D, 3.5+/-0.2 mm with cyclopentolate, and 5.3+/-1.2 D, 5.20+/-1.3 D, 3.4+/-0.2 mm with atropine, respectively. When these obtained data were compared by the Student's t test no statistical significance was found (p > 0.05). CONCLUSIONS: We suggest that the cyclopentolate cycloplegia applied to the patients with refractive accommodative esotropia is sufficient to produce good cycloplegia, with an effect similar to atropine.

Accommodation, Ocular↗
PubMed2001

Biometric measurements of the eyes in teenagers and young adults with Down syndrome.

PURPOSE: To examine ocular biometric variables in subjects with Down syndrome. METHODS: In a population-based study we have compared ocular biometric variables in a group of 47 individuals with Down syndrome (20.0+/-3.9 years) with 51 control subjects (21.0+/-4.6 years). RESULTS: A thinner cornea (0.48+/-0.04 mm vs. 0.55+/-0.03 mm, p<0.001) and higher keratometry values (46.39+/-1.95 D vs. 43.41+/-1.40 D, p<0.001) were found in the Down syndrome group than in the control group. Oblique astigmatism was commonly found in the Down syndrome individuals, showing a strong right-left specificity (right eyes' axes in the 135 degrees -meridian, left eyes' axes in the 45 degrees -meridian). The lens was thinner (3.27+/-0.29 mm vs. 3.49+/-0.20 mm) and the calculated lens power was weaker (17.70+/-2.36 D vs. 19.48+/-1.24 D) in the Down syndrome group than in the control group (p<0.001 in both cases). CONCLUSIONS: Thinning of the corneal stroma may account for the steeper cornea and the high frequency of astigmatism in Down syndrome due to lower corneal rigidity. It may also be of etiological importance to the increased incidence of keratoconus in Down syndrome.

Accommodation, Ocular↗
PubMed1992

[Biometric data of eyes after the onset of acute glaucoma].

Biometric measurements were performed in 67 patients after acute glaucoma and in 67 patients of a matched control group. For patients with acute glaucoma the subjective refraction was +0.91 +/- 2.82 dpt, ocular axial length was 21.73 +/- 0.96 mm, lens thickness was 4.95 +/- 0.63 mm and the ratio lens thickness to ocular axial length amounted to 2.27 +/- 0.29. There was a statistically significant difference between the glaucoma and the control group concerning the parameters subjective refraction, ocular axial length, lens thickness and the lens thickness to axial length ratio. A statistically significant positive correlation was found between corneal radius and axial length, both, in the control and the glaucoma group, a significant negative correlation between axial length and subjective refraction only in the control group. In contrast to other authors, who reported on patients with narrow angle glaucoma with and without acute attack; we found no significant difference. These results support the suggestion that biometric data do not allow a prediction whether a patient with narrow anterior chamber angle will suffer glaucoma attack or not. The etiology of this disease seems to have a multifactorial origin.

Acute Disease↗
PubMed2006

Levels and distribution pattern of polychlorinated biphenyl (PCB) congeners in razor clams Ensis siliqua (Linnaeus, 1758) from Galicia (north-west Spain) in relation to biometric parameters.

To establish polychlorinated biphenyl (PCB) levels and distribution as well as their relationship to biometric parameters in the razor clam Ensis siliqua (Linnaeus, 1758), 15 individual samples collected from two points sited in the Islas Cies, Ría de Vigo in Galicia, Spain, collected monthly between February 2003 and April 2004, were analysed. PCBs (IUPAC No. 31, 28, 52, 101, 118, 153, 105, 138, 156 and 180) were isolated by Soxhlet extraction. Identification and quantification were performed by gas chromatography-mass spectrometry (GC/MS) and gas chromatography (electron capture detector), respectively. The isomer concentrations in E. siliqua were in the order hexachlorobiphenyls > pentachlorobiphenyls > heptachlorobiphenyls > trichlorobiphenyls > tetrachlorbiphenyls. No correlation was observed between the E. siliqua shell length and PCBs levels. The PCBs 31, 101, 105 and 153 levels were statistically related with some biometric parameters (p < 0.05). Multivariate techniques such as principal component analysis (PCA) show clear seasonal differences between samples.

Animals↗
PubMedDate not supplied

The impact of advances in medicine on the biometric analysis of infant mortality.

Bourgeois-Pichat's biometric model was developed as a method to decompose infant mortality into endogenous and exogenous components. The model assumes that no endogenous deaths occur after the first month of life. This paper uses data for the United States to examine the hypothesis that recent advances in medicine extend endogenous mortality past the first month of life. The biometric model is found consistently to underestimate the endogenous infant mortality rate and to overestimate the exogenous infant mortality rate relative to cause of death analysis. Direct examination of the age distribution of infant mortality shows that the proportion of all infant mortality that occurs in the first month of life declined from 75.37 per cent in 1970 to 65.40 per cent in 1985, and that a significant and increasing proportion of the mortality occurring after the first month of life is due to endogenous causes. The development of new empirical models is suggested.

Biometry↗
PubMed2002

Comparative Genometrics (CG): a database dedicated to biometric comparisons of whole genomes.

The ever increasing rate at which whole genome sequences are becoming accessible to the scientific community has created an urgent need for tools enabling comparison of chromosomes of different species. We have applied biometric methods to available chromosome sequences and posted the results on our Comparative Genometrics (CG) web site. By genometrics, a term coined by Elston and Wilson [GENET: Epidemiol. (1990), 7, 17-19], we understand a biometric analysis of chromosomes. During the initial phase, our web site displays, for all completely sequenced prokaryotic genomes, three genometric analyses: the DNA walk [Lobry (1999) Microbiology Today, 26, 164-165] and two complementary representations, i.e. the cumulative GC- and TA-skew analyses, capable of identifying, at the level of whole genomes, features inherent to chromosome organization and functioning. It appears that the latter features are taxon-specific. Although primarily focused on prokaryotic chromosomes, the CG web site contains genometric information on paradigm plasmids, phages, viruses and eukaryotic organelles. Relevant data and methods can be readily used by the scientific community for further analyses as well as for tutorial purposes. Our data posted at the CG web site are freely available on the World Wide Web at http://www.unil.ch/comparativegenometrics.

Bacteriophages↗
PubMed1980

Biometrics in the medical school curriculum: making the necessary relevant.

Biometrics has been perceived by freshman medical students as a necessary but not immediately relevant part of their medical training. Because a student is more likely to learn and retain course content if he feels it is relevant, an attempt was made to change the students' perception of the biometrics course by introducing statistical methods as a means of solving some problems in the interpretation of clinical laboratory data. Retrospective analysis of student course evaluations over the last five years indicates that a significant change in student perception of the relevance of the course did occur.

Biometry↗
PubMed2005

Refractive and biometric changes with silicone hydrogel contact lenses.

PURPOSE: This study reports data from an 18-month longitudinal study of neophyte contact lens wearers and compares changes in ocular refraction and biometry induced by daily wear and continuous wear of two different silicone hydrogel (SiH) materials. METHODS: Forty-five subjects were enrolled in the study and randomly assigned to wear one of the two silicone hydrogel materials: Lotrafilcon A or Balafilcon A lenses on either a daily or continuous wear basis. Measurements of objective refraction, axial length, anterior chamber depth, corneal curvature, and the rate of peripheral corneal flattening were performed before and 1, 3, 6, 12, and 18 months after initial fitting. RESULTS: Mean spherical equivalent refractive error increased in the myopic direction in all contact lens groups across time (p < 0.001). Axial length was the main biometric contributor to the development of myopia. After 18 months of lens wear, subjects in the Lotrafilcon A group showed the greater mean increase in myopia (i.e., -0.50 D). CONCLUSIONS: The results of this study show that increases in myopia, similar if not higher than those found to occur normally in young adult noncontact lens wearers, still occur with silicone hydrogel contact lens wear. The main biometric contributor to the progression of myopia was an increase in axial length. Differences between our results and those of previous studies with silicone hydrogel contact lenses could be attributed to the differing populations used in which both age and occupation may have played a role.

Adult↗
PubMed2005

A biometric identification system based on eigenpalm and eigenfinger features.

This paper presents a multimodal biometric identification system based on the features of the human hand. We describe a new biometric approach to personal identification using eigenfinger and eigenpalm features, with fusion applied at the matching-score level. The identification process can be divided into the following phases: capturing the image; preprocessing; extracting and normalizing the palm and strip-like finger subimages; extracting the eigenpalm and eigenfinger features based on the K-L transform; matching and fusion; and, finally, a decision based on the (k, l)-NN classifier and thresholding. The system was tested on a database of 237 people (1,820 hand images). The experimental results showed the effectiveness of the system in terms of the recognition rate (100 percent), the equal error rate (EER = 0.58 percent), and the total error rate (TER = 0.72 percent).

Algorithms↗
PubMedDate not supplied

Age dependence of ocular biometric measurements under cycloplegia with tropicamide and cyclopentolate.

BACKGROUND: Cyclopentolate continues to be the cycloplegic of choice for refracting young children, although many studies of ocular biometry promote the use of tropicamide. METHODS: To clarify the role of drug type in biometric measurements, cycloplegia was induced in two disparate age groups using cyclopentolate and tropicamide on two separate occasions. Refraction, phakometry and A-scan ultrasonography measurements were made on two groups of Tibetan children resident in Nepal. RESULTS: Cyclopentolate produced significantly more cycloplegia in the younger group, which was supported by phakometry measurements. However, in clinical terms, the difference between the measurements was not significant. CONCLUSION: We conclude that although cyclopentolate is more effective than tropicamide in relaxing accommodation in young children, the use of a local anaesthetic prior to instillation of tropicamide produces refractive data virtually equivalent to that of cyclopentolate, regardless of the age group measured. However, biometric measurements may be susceptible to greater error when near fixation targets are used during phakometry procedures.

Journal Article↗