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Biomedical subjects

R Beck

Publications and source records attributed to R Beck.

At least 127 records · Page 7Linked to original sources
PubMed1990

Patterns of enamel hypoplasia in two medieval populations from Nubia's Batn el Hajar.

Analysis of enamel hypoplasia frequencies for two medieval populations representing the earliest and latest Christian periods of ancient Nubia reveals important diachronic shifts in childhood stress. The mean frequency for hypoplastic bands among the early Christians is 4.2, while the late Christian sample has a mean frequency of 3.7. In addition, the earlier Christians show a prolongation of hypoplastic occurrences through childhood corresponding to a prolonged period of intensified childhood mortality. The modal time interval between hypoplastic occurrences is also shorter for the early Christian children. A comparison of hypoplasia frequencies by sex also reveals a pattern of considerable interest. Females show both lower frequencies of hypoplasias as well as a delay in onset. The diachronic differences are consistent with other indications from paleopathology and paleodemography that childhood stress decreased in later Christian times. The sex differences suggest that during the infancy and early childhood females were more resilient than their male counterparts.

Age Factors↗
PubMed1990

Evaluation of the rapid Patho Dx Latex Strep Grouping Kit.

A variety of clinical specimens from throat, nose, ear, eye, wounds, urine, and vagina were collected, cultured, and screened for beta-hemolytic streptococci. The Patho Dx Latex Strep Grouping Kit (Diagnostic Product Corp., Los Angeles, Calif.) technique was applied to colonies taken right from the primary cultures. Isolated strains were sent to the reference laboratory where they were grouped by standard techniques. The kappa coefficient of agreement between the Patho Dx Kit and the standard method was 0.958. We believe that, although better agreement was achieved by others with isolated colonies, a very good agreement is also achieved with primary cultures. The fact that the laboratory is able to report an accurate answer after only 24 h seems most advantageous.

Diagnostic Errors↗
PubMed1990

The reproducibility of forced expiratory wheezes.

Previous work has shown forced expiratory wheezes (FEW) to be associated with onset of flow limitation and to have spectral characteristics similar to wheezes heard in patients with obstructive lung diseases. This study was designed to determine whether the acoustic characteristics of FEW are reproducible under controlled lung volume and flow conditions. Six healthy, nonsmoking young adults 28 to 37 yr of age were studied. They performed FVC maneuvers through a set of round apertures (diameters, 14, 12, 10, 8, 6, 4, 2, and 1 mm). Flow, measured with a pneumotachograph, and tracheal lung sounds, recorded with a Hewlett-Packard HP20510A contact sensor, were recorded simultaneously on magnetic tape and analyzed off-line. For each subject, data from three different aperture sizes, measured in triplicates, were analyzed (total of 54 runs); 199 different wheezes were identified (mean, 3.7 wheezes/run), and 56.7 +/- 5.1% (mean +/- SEM) of wheezes found in a certain run (range, 41.7 to 77.8%) were identical to wheezes found in the other two runs of the same aperture size (i.e., same flow rate). In 17 of the 18 sets of triplicate runs analyzed, at least one major wheeze was identical in all three runs of the set. In three of the sets, two different identical wheezes were found. These findings support a deterministic mechanism of generation of wheezes and is in line with the predictions of the "flutter theory."

Adult↗
PubMed1990

Gadolinium-DTPA-enhanced magnetic resonance imaging in optic neuropathies.

Magnetic resonance imaging (MRI), after intravenous administration of the paramagnetic agent gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), showed enhancement of the optic nerve in 7 of 13 patients with acute optic neuritis. Four of these patients had Gd-DTPA enhancement of the intracranial optic nerve and two had involvement of the optic nerve at the orbital apex, ipsilateral to the eye with visual loss. Gadolinium-DTPA enhancement of both intracranial optic nerves was seen in one of two patients with bilateral retrobulbar neuritis. Two patients with acute radiation-induced optic neuropathy also had Gd-DTPA enhancement of the intracranial optic nerve. The authors recommend MRI with Gd-DTPA as the neuro-diagnostic procedure of choice for visualization of increased permeability of the blood-brain barrier in acute optic neuritis and radiation-induced optic neuropathy.

Adolescent↗
PubMed1989

Loads on the lumbar trunk during level walking.

The goal of this study was to estimate the loads internal to the lumbar trunk that arise during level walking. To do this, (a) trunk muscle activities were calibrated in terms of muscle contraction force levels in a set of isometric exertions; (b) trunk muscle myoelectric activities were measured during level walking; and then (c) the muscle contraction forces that arose during walking were calculated from these measurements and calibrations. Lumbar trunk muscle myoelectric activities were quantified in 10 healthy young males. Myoelectric activities were monitored using eight bipolar surface electrode pairs placed around the trunk at the level of the third lumbar vertebrae. The subjects first performed four static weight-resisting tasks to calibrate muscle force/activity relationships. They then traversed a 8.25 m walkway three times each at cadences of 72 and 120 steps/min. A biomechanical model incorporating 22 lumbar trunk muscles was used to predict muscle contraction forces for the calibration tasks. Predicted forces were linearly correlated with the measured myoelectric activities for these tasks. The regression equations were then interpolated to estimate the muscle contraction forces from the myoelectric data during gait. Peak contraction forces for the iliocostalis muscles were calculated to be approximately 55 N per side, corresponding to total erector spinae peak contractions on the order of 140 N per side. For the other six muscles that were monitored, contraction forces were less than 15 N per side. This suggests that peak net reaction moments and peak spine compressions on the lumbar trunk during these walking tasks were on the order of 15 Nm and 1.2 times body weight, respectively.

Abdominal Muscles↗
PubMed1989

[Retinopathic visual loss in hemorrhagic necrotizing pancreatitis].

Pancreatic retinopathies have been described with reference to case histories since 1975. Descriptions differed greatly from each other with regard to onset, development, and residual vision along with impairment. Two of the author's own cases are reported in this paper. Agreement with pathological patterns published elsewhere (alcohol-related genesis, age) are compared to points of difference (juncture of manifestation, final condition). Aetiology has proved to be of multifactorial nature, with presence and involvement of fat embolism or granulocyte aggregation being possible. Reference is made to elements with relevance to prognosis. The demand is made for no-delay treatment and routine checks.

Acute Disease↗
PubMed1989

[Computer-assisted tissue analysis for cancer detection in breast ultrasound--significance of reference values].

Due to the inhomogeneous and very variable structure of healthy tissue of the female breast it is often very difficult to detect a carcinoma via computer-aided sonography. The present study based on preoperative measurements in 29 woman patients with carcinoma of the breast aimed at finding out to what extent it would be possible to circumvent this problem by means of additional reference measurements in healthy tissue. For this purpose, relative image parameters were determined besides absolute ones from measurements in tumorous and healthy reference tissue. These relative image parameters are much more suitable for subsequent decision analysis on account of their narrower range of variation. The results obtained in this manner could be improved further by additional optimization or extension (such as analysis of other combinations of parameters, by enlarging the field of measurement and hence the data available per tissue sample, use of higher or even different ultrasound frequencies).

Adipose Tissue↗
PubMed1988

Cystic fibrosis: enhanced theophylline metabolism may be linked to the disease.

Theophylline disposition (5.5 mg/kg administered intravenously) was studied in 12 patients with cystic fibrosis (CF) and 16 healthy control volunteers. Dietary controls and logs were used to minimize the influence of food on theophylline metabolism. Control subjects were restudied in random order on two subsequent occasions after 2 weeks of either pancreatic enzymes or placebo. Theophylline and its three main metabolites, 1-methyluric acid, 3-methylxanthine, and 1,3-dimethyluric acid, were analyzed in serum and urine by HPLC. The total body clearance, renal clearance, nonrenal clearance, and volume of distribution of theophylline were significantly greater (p less than 0.05) in patients with CF than in control subjects. The increased nonrenal clearance was the result of increased biotransformation to each of the three main metabolites. Patients with CF exhibited enhanced N-demethylation and 8-hydroxylation of theophylline, pathways that appear to be mediated by two different families of P-450 enzymes. Theophylline clearance after 2 weeks of pancreatic enzyme administration in the control subjects was the same as with placebo. Possible reasons for enhanced theophylline biotransformation in CF are discussed.

Adolescent↗
PubMed1988

Intravenous gammaglobulin therapy for neonatal alloimmune thrombocytopenia.

A clinical experience with the combined use of intravenous gammaglobulin and platelet transfusions in a neonate with alloimmune thrombocytopenia secondary to PLA1 incompatibility is described and compared to a previously affected sibling treated with a conventional regimen of corticosteroids, random donor platelet transfusions, and exchange transfusion for neonatal alloimmune thrombocytopenia.

Antibodies↗
PubMed1988

[Twin pregnancy with fetal hydrocephalus].

There is a case report on twin pregnancy with fetal hydrocephalus, recognized in the 24th week of gestation. Course of pregnancy and management during labour are described. The peculiarity of our observation is for the constellation mother--healthy fetus--fetus with hydrocephalus. Taking care for the pregnant woman and the healthy fetus are most important.

Abnormalities, Multiple↗