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Results for “Biometry”

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At least 1,225 records · Page 68Linked to original sources

PubMed1997

[Minimal lesion hypertensive retinopathy and arterial pre-hypertension: evidence of arterial pressure monitoring in presumed normotensive subjects at zero risk].

The present study investigates the blood pressure (BP) 24 h pattern in 25 subjects who were found to show some incipient signs of hypertensive retinopathy, although they were diagnosed as normotensive by means of casual sphygmomanometry. BP was controlled by means of non invasive ambulatory monitoring. A comparable number of normotensive subjects without fundoscopic signs of hypertensive retinopathy was investigated as a control group. BP times series were analyzed by means of conventional and rhythmometric biometry. The biometric estimates suggest that the subjects with incipient hypertensive retinopathy show a significantly higher level of daily systolic BP even though their BP values remain below the reference limits. This finding suggests that the hypertensive retinopathy may exist in a non-zero stage characterizable as minimal change tensive retinopathy. This retinal picture occurs in subjects who show a pre-hypertensive stage in their BP 24 h pattern.

Adolescent↗

PubMedDate not supplied

[Vasculitis and viral infection].

Viruses have been implicated in vasculitis. To determine activity of viral infection associated with vasculitis. 17 patients with vasculitis had been in immunological and antiviral antibodies evaluation. Twenty five healthy controls sex and age matched with hematic biometry (BH) and AA. All subjects were negative to HIV and HBV. Viral activity was demonstrated in eight patients; vascular purpura (5), Takayasu disease (1), polyarteritis nodosa (1), erythema nodosum (1). None subject of control group had IgM activity. Antibodies response of IgG in patients were of lesser intensity than in control group. 14 abnormalities in BH were found in patients and 4 in control group. Immune response in patients, measured by lymphocyte subpopulations and circulating immune complexes was abnormal. In conclusion 47% showed viral activity, but the dominant feature was abnormal immune response in 82%.

Adult↗

PubMed1997

[Infrasound: body's effects and hygienic regulation].

The paper analyzes and sums up technically originated infrasound (IS) hygienic problems. Trends for an increase in its role as an unfavourable factor of the industrial, transport, and residential environments are established. Comprehensive physiological, hygienic, and experimental studies revealed the pathogenetic features of IS. Involvement of the limbicoreticular complex, hypothalamus, and other subcortical structures into responses to higher factor levels on human beings stipulates a sharply prominent pathological discomfort as a manifestation of the infrasonic diencephalic hypothalamic syndrome with sensorisomatic and autonomic visceral symptoms. A conceptual pathogenetic model of IS exposure has been worked out. Main subjective and objective signs of and criteria for IS exposure have been defined, its ranking by human risk areas is given with the influencing factor parameters borne in mind. The biometry of biological effects on exposure to IS at 4 and Hz and at 130 dB and their changes in the vestibular and acoustic analyzers, as well as in the neurohumoral regulation system and other homeostatic parameters has revealed the priority of the whole body's responses.

Animals↗

PubMedDate not supplied

Second-trimester placental volumes predict birth weight at term.

OBJECTIVE: To test the hypothesis that second-trimester placental growth is a major determinant of size at birth in healthy, active women. METHODS: Three serial measurements of fetal morphometry and placental volume were obtained between the 14th and 26th weeks of an accurately dated singleton pregnancy in 40 subjects. RESULTS: Second-trimester placental volumes were variable, increasing from (mean +/- standard deviation) 130 +/- 35 to 248 +/- 67 and to 375 +/- 92 cm3 at 16, 20, and 24 weeks, with an average growth rate of 31 +/- 8 cm3/weeks. At delivery, fresh placental volumes and birth weights were also variable, ranging between 304-823 cm3 and 2.6-4.4 kg, respectively. Significant correlations (r > 0.79) were present between second-trimester placental volume or growth rate and placental volume at delivery and birth weight, corrected for gestational age and infant sex. However, correlations between second-trimester fetal biometry and both corrected birth weight and birth weight percentile were poor (r < 0.45). CONCLUSION: Second-trimester placental volumes and growth rates are good predictors of size at birth in healthy, active women. We speculate that this technique may have real value as an early screening tool to identify cases at risk of anomalous third-trimester growth.

Adult↗

PubMed1997

Random effects probit and logistic regression models for three-level data.

In analysis of binary data from clustered and longitudinal studies, random effect models have been recently developed to accommodate two-level problems such as subjects nested within clusters or repeated classifications within subjects. Unfortunately, these models cannot be applied to three-level problems that occur frequently in practice. For example, multicenter longitudinal clinical trials involve repeated assessments within individuals and individuals are nested within study centers. This combination of clustered and longitudinal data represents the classic three-level problem in biometry. Similarly, in prevention studies, various educational programs designed to minimize risk taking behavior (e.g., smoking prevention and cessation) may be compared where randomization to various design conditions is at the level of the school and the intervention is performed at the level of the classroom. Previous statistical approaches to the three-level problem for binary response data have either ignored one level of nesting, treated it as a fixed effect, or used first- and second-order Taylor series expansions of the logarithm of the conditional likelihood to linearize these models and estimate model parameters using more conventional procedures for measurement data. Recent studies indicate that these approximate solutions exhibit considerable bias and provide little advantage over use of traditional logistic regression analysis ignoring the hierarchical structure. In this paper, we generalize earlier results for two-level random effects probit and logistic regression models to the three-level case. Parameter estimation is based on full-information maximum marginal likelihood estimation (MMLE) using numerical quadrature to approximate the multiple random effects. The model is illustrated using data from 135 classrooms from 28 schools on the effects of two smoking cessation interventions.

Clinical Trials as Topic↗

PubMedDate not supplied

[Ultrasonography of lens crystalline in patients with primary open-angle glaucoma].

One- and two-dimensional examination of the lens supplemented with biometry was carried out in patients with primary open-angle glaucoma. Echobiometry revealed a relationship between the thickness of the lens and type of cataract. Analysis of echographic images of the lens and biomicroscopy findings demonstrated the value of this method for the early objective assessment of cataract progress in patients with glaucoma, specifically, after antiglaucoma surgery.

Cataract↗

PubMed1996

Relationship between myopia and optical components--a study among Chinese Hong Kong student population.

PURPOSE: To establish the prevalence and severity of myopia among the Chinese Hong Kong students and to study the relationship between myopia and optical components. METHODS: One thousand and seventy-five freshmen of the 1993-1994 academic year in the Chinese University of Hong Kong underwent the eye examination including evaluation of refractive error, keratometry, and A-scan ultrasonic biometry. The data were analyzed with the SPSS/PC+4.01 statistical package. RESULTS: The prevalence of myopia was 91.7% with the mean refraction being -4.00 +/- 2.64D in this young adult population. The statistical analyses demonstrated a significant correlation between refractive value and axial length of the globe (r = -0.78), vitreous length (r = -0.76), anterior chamber depth (r = -0.33), lens thickness (r = 0.13) and corneal curvature (r = 0.19). CONCLUSION: The refractive status is mainly dependent on the axial length. In general, the higher the myopia was, the longer the eyeball, the deeper the anterior chamber, the steeper the cornea, and the thinner the lens would be.

Adolescent↗

PubMed1976

[Determination of gestational age by sonar (author's transl)].

For some time it has been recognized that abnormal intrauterine development can lead to dissociation between maturity and external size and/or weight of the fetus. The results of pathophysiological and biochemical studies of fetal growth and nutrition have resulted in attempts to monitor and time every pregnancy at risk. The most recent information in the area of intrauterine development has shown that also organic and functional maturity of fetal organ systems can develop dissociated from gestational age. This observation points out the necessity for additional measures in order to achieve the goals of Planed obstetrics. The possibilities of ultrasound biometry for determining gestational age were presented. Taking normal and abnormal fetal growth and behavior into consideration, the use of ultrasonic diagnostic methods makes it possible to acquire concrete data regarding the size and maturity of some fetal organ systems. The methodological problems such as arise in clinical practice were explained and discussed in light of the most recent developments in equipment.

Anthropometry↗

PubMed1998

Intrauterine growth restriction: identification and management.

Intrauterine growth restriction (IUGR) is a common diagnosis in obstetrics and carries an increased risk of perinatal mortality and morbidity. Identification of IUGR is crucial because proper evaluation and management can result in a favorable outcome. Certain pregnancies are at high risk for growth restriction, although a substantial percentage of cases occur in the general obstetric population. Accurate dating early in pregnancy is essential for a diagnosis of IUGR. Ultrasound biometry is the gold standard for assessment of fetal size and the amount of amniotic fluid. Growth restriction is classified as symmetric and asymmetric. A lag in fundal height of 4 cm or more suggests IUGR. Serial ultrasonograms are important for monitoring growth restriction, and management must be individualized. General management measures include treatment of maternal disease, good nutrition and institution of bed rest. Preterm delivery is indicated if the fetus shows evidence of abnormal function on biophysical profile testing. The fetus should be monitored continuously during labor to minimize fetal hypoxia.

Female↗

PubMed1998

[Aging of the crystalline lens and presbyopia].

The crystalline lens changes both optically and mechanically with age: it becomes less transparent and more difficult to deform. Using a new ultrasound technique, Continuous Ultrasonographic Biometry (CUB), we were able to demonstrate that presbyopia is caused by increased stiffness of the lens due to changes in lens fibre membranes and cytoskeleton. These results are important for further research on the ageing processes that lead to cataract and presbyopia, and the treatment of these conditions.

Adolescent↗

PubMed1998

Eye elongation during accommodation in humans: differences between emmetropes and myopes.

PURPOSE: The pathophysiology and pathogenesis of myopia are still a matter of controversy. Exaggerated longitudinal eye growth is assumed to play an important role in the development of myopia. A significant correlation between refraction and amount of near-work has been reported. However, current knowledge of changes of axial eye length with accommodation is limited because clinical ultrasound biometry does not provide the precision and resolution required to thoroughly investigate these phenomena. METHODS: Partial coherence interferometry (PCI), a noninvasive biometric technique, uses laser light with short coherence length in combination with interferometry to achieve precision in the micrometer to submicrometer range and resolution of 10 microm. In the present study this technique was used to investigate axial eye length changes in 11 emmetropic and 12 myopic eyes during monocular fixation at the far and near point. In 7 subjects, the contralateral eye has also been measured to investigate interocular differences in eye elongation. RESULTS: All investigated eyes elongated during accommodation. This elongation was more pronounced in emmetropes than in myopes (P < 0.001). Mean accommodation-induced eye elongations of 12.7 microm (range, 8.6-19.2 microm) and 5.2 microm (range, 2.1-9.5 microm), corresponding to a dioptric change of approximately -0.036 D and -0.015 D, were obtained for emmetropes and myopes. No significant difference in accommodative amplitudes between groups (5.1 +/- 1.2 D [range, 3.8-7.1 D] versus 4.1 +/- 2.0 D [range, 1.0-7.1 D]; P = 0.14) was detected. No significant interocular difference in accommodation-induced eye elongation was revealed (P = 0.86). Also, a mean backward movement of the posterior lens pole of 38 microm (range, 9-107 microm) was observed in both study groups. CONCLUSIONS: The detected eye elongation can be explained by the accommodation-induced contraction of the ciliary muscle, which results in forward and inward pulling of the choroid, thus decreasing the circumference of the sclera, and leads to an elongation of the axial eye length. Finally, it was demonstrated that PCI, in contrast to clinical ultrasound, is capable of characterizing eye length changes during accommodation in humans.

Accommodation, Ocular↗

PubMed1998

[Scleroplasty surgery in the treatment of progressive myopia in children].

The authors evaluate the results of 257 scleroplastic operations performed in 145 children with progressive myopia in 1989-1995. The age range of the operated children was 5-17 years. The mean age at the time of operation was 10.4 +/- 3.9 years. The children were followed up for at least two years before and two years after operation. All children met the condition of progressive myopia, minimal refraction -6.0 D and progression of at least 1 D per year during the last two years before surgery. The authors investigated the axial length of the bulbus by biometry, objective and subjective refraction, the best corrected visual acuity before and after surgery. The mean progression of myopia two years after the scleroplastic operation declined to a mean value of 0.29/year. No serious complications were recorded. Scleroplasty can be considered a safe surgical method which can help to improve the unfavourable development of progressive myopia.

Adolescent↗

PubMed1998

[A breech delivery and induction with prostaglandin E2].

Induction of labour with local application of PgE2 in breech presentation is still a much discussed problem. We aimed at studying the effect of local application of PgE2 (Prostin E2--3 mg) vaginal tablets for induction of labour in breech presentation. 15 pregnancies were studied and induced--8 for postdate, 6 for prae-eclampsia and 1 for fetal demise. Sonographic biometry and cardiotocographic examinations were conducted as well as a precise bishop score. Labour began within the interval of 3-13 hours after the application on the first tablet. The length of delivery was 4-24 hours. Effective labour was instituted in 93.33% on the parturiens, while in 1 (6.67%) there was a need for augmentation with oxytocin. There were no cases of hyperstimulation. Vaginal delivery was accomplished in 100% of the patients among which the breech was delivered with the classical manoeuvre in 10 cases and by the Bracht manoeuvre in 5 cases. Our results show, despite is small case number, that with favourable pelvic scores and absence of cephalopelvic disproportion and fetal distress PgE2 induction can be done locally even for breech presentation.

Breech Presentation↗

PubMed1998

[Pelvic trauma and pregnancy. Literature review and case report].

The authors are dealing with a case of a pelvic fracture (right superior pubic ramus) after a road traffic accident to a patient who arise a pregnancy with twins at twenty five weeks pregnant. Seven per cent of a road traffic accident affect pregnancy with a maternal death rate from eight to sixteen per cent and a fetal death rate up to fifty seven per cent. Pelvic trauma are more deleterious during the pregnancy because of the gravide uterus, of the abdominal injuries binding more often, and of pregnancy secondary maternal physiology which lead to delay diagnosis and therapeutics. Blunt fetomaternal consequences are ruled by pelvic haematomas, uterine rupture, prematurity, acute fetal distress, fetal injuries and in utero death. At mid and long range arise the problem of child birth way and the risk of mechanical dystocy. Cesarean is store in case of vesical and urethral injuries, or perineal injury, several pelvic fractures or in case of the pelvic belt fracture moved and not reduced, bringing to a surgical unsymmetrical pelvis. In the other cases, the obstetrical prognoses will be done after a dialogue with all medical staff and a full synthesis of the file based on the fetopelvic comparisons (obstetrics previous, clinic, fetal biometry, pelvimetry X ray).

Abdominal Injuries↗

PubMed1956