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Biomedical subjects

R Belitzky

Publications and source records attributed to R Belitzky.

11 recordsLinked to original sources
PubMed1980

[What scientific publications should be read?].

Students in the biomedical fields, and even those at the graduate level, often tend to accept more readily the opinions of authority than scientific knowledge itself. Books and papers sometimes confuse hypotheses with evidence. Similarly, the great profusion of scientific publications makes it necessary to sift the sound from the fatuous, the important from the trivial, the useful from the dangerous. A good way to choose one's reading matter is to learn the scientific method and to consider each article from that point of view. Is the writing a mere description of phenomena, a study of case histories, a presentation of new techniques, or a report of really valid experimental work? One should be aware of the scope and limitations of experimental design models applicable to physiological and biochemical research and of those for clinical experimentation. This paper offers guidelines for the analysis of articles and indicates the need to determine whether the components of an experimental design (a target population, alternative therapies, and situations of change) are present, and to review its structure and the sequence it prescribes on that basis. Several questions are asked following the above steps, as a quick gauge of the value and usefulness of the publication or paper.

Education, Medical↗
PubMed1978

Early postnatal growth evaluation in full-term, preterm and small-for-dates infants.

Postnatal growth patterns of weight, length/height and head circumference in full-term (FTI), preterm (PTI) and small-for-dates (SFDI) infants, are described by using distance and velocity data together with the concept of growth per unit of body weight. The study was performed in 112 healthy Caucasian infants, of a similar socioeconomic status, in Montevideo, Uruguay. Median growth velocity (MGV) and median growth velocity per unit (MGVU) of body size are defined. The authors stress that: (a) growth velocity is related to body mass, (b) a useful evaluation of growth is made by using two consecutive measures with a certain time interval independently of birthweight and gestational age, and (c) expressing growth per day per unit relates well to daily nutritional and other requirements.

Age Factors↗
PubMed1977

Passage of mannitol from mother to amniotic fluid and fetus.

Ten pregnant women and three pregnant sheep received mannitol intravenously. The results show that during late pregnancy this substance appears in amniotic fluid, and when the fetus is alive, its concentration increases with time, reaching values which are higher than those simultaneously obtained in maternal plasma. The experiments performed in sheep show that in fetal urine the concentration of mannitol reached values 10 to 20 times higher than those found in fetal plasma. This supports the hypothesis that the fetal kidney has an important role in the transference of this type of substance from the mother to the amniotic fluid.

Amniotic Fluid↗
PubMed1976

Transference of para-amino-hippurate from the mother to the amniotic fluid.

There are few studies in which substances mainly cleared by the kidney are injected to the mother and the time course of their concentrations in amniotic fluid is analyzed. This type of studies may contribute to the knowledge of the transference of substances through the mother-fetus-amniotic fluid complex. Thirteen pregnant women were studied. Eleven with normal term pregnancies, and the remaining two mothers were at the 36th week of gestation and their fetuses were dead. A saturation dose of para-amino-hippurate (PAH) (8 mg/kg) was administered intravenously to all subjects. This dose was followed by a continuous infusion at a rate of 380 mcg/min/kg during 30 minutes in 11 mothers. In one of the remaining subjects, the infusion rate was 240 mcg/min/kg during 160 minutes and in the other, it was 50 mcg/min/kg for 450 minutes. Samples of maternal blood and amniotic fluid were simultaneously obtained, before PAH administration and at variable intervals thereafter. In mothers with live fetuses, PAH concentration in amniotic fluid increased not only during the infusion but also for at least two hours after its interruption (Fig. 2, Tab. I). When the infusion lasted enough and with stabilized PAH concentration in maternal plasma, amniotic fluid concentration of PAH attained higher values than in the mother (Fig. 1). Disappearance of PAH from amniotic fluid was very slow (45% in 5 hours) (Fig. 2). In cases with dead fetuses, the pattern of PAH concentration in amniotic fluid was completely different. The highest concentration was observed already in the first sample at the end of the infusion. From there on, no increment was recorded, and as soon as maternal blood concentration fell below the values of amniotic fluid, PAH began to disappear from this compartment at a much faster rate (45% in 1 hour) (Fig 3). The progressive rise of PAH in amniotic fluid may be explained as follows: (Fig. 5). PAH diffuses from maternal blood to fetal blood through the placenta. The fetal kidney removes PAH from fetal blood and concentrates it in urine. Periodic fetal micturition causes the rise of PAH in amniotic fluid. PAH may return from amniotic fluid to fetal blood mainly because of fetal swallowing; and the larger part of this PAH will be again excreted by the kidney into the amniotic compartment. This mechanism would explain the slow disappearance of the substance from amniotic fluid after the end of the infusion, and also the lack of correlation between concentrations in maternal plasma and amniotic fluid. Diffusion of PAH between blood and amniotic fluid may also exist through the walls of the vessels of the ovular membranes and the vessels of the umbilical cord; this mechanism would play a minor role in the concentration of PAH in amniotic fluid in subjects with live fetuses. Our results also show that mean PAH concentration in amniotic fluid increases as a linear function of time until 150 minutes after the onset of PAH administration to the mother (Fig. 4).

Aminohippuric Acids↗
PubMedDate not supplied

Congenital malformations in diabetic offspring.

A retrospective study of 215 deliveries in diabetic mothers at Hospital de Clínicas (Montevideo, Uruguay) has been performed. Presence of congenital malformations (CM) was considered in relation to age of the mothers, class of maternal diabetes, maternal angiopathy, treatment and metabolic control. The prevalence of CM in the series was 9.8%. None of the factors analyzed seems to be statistically linked to the prevalence of CM.

Congenital Abnormalities↗