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Biomedical subjects

S Frenk

Publications and source records attributed to S Frenk.

At least 19 recordsLinked to original sources
PubMed1992

[Omega-6 and omega-3 polyunsaturated fatty acids in healthy and sick children under 5 years of age. Part II. Pathologic metabolism].

Today, the long-chain polyunsaturated fatty acids, omega 6 and omega 3, are of special interest to different research groups, all over the world, due to its physiological and metabolic importance. This paper presents different cases of fatty acids deficiency from which the cases of premature low-birth-weight neonates and children under 5 years old presenting severe malnutrition, stand out. In addition, various inherited pathological processes that involve the mechanism of oxidation of these nutrients, are also described.

Child Nutrition Disorders↗
PubMed1992

[Omega-6 and omega-3 polyunsaturated fatty acids in healthy and sick children under 5. I. Normal metabolism].

The polyunsaturated fatty acids, omega 6 and omega 3, are organic compounds that have to do with the daily caloric intake; the tissue deposits of energy reserve, as well as the general intermediary metabolism of the human organisms and the composition of all the cellular membranes. This article is about its general characteristics: chemical structure, essenciality, biosynthesis, and physiological and metabolical functions; its compounds and metabolites derived; its organic distribution, and the quantity found in food in general. Of all these, special emphasis are made on the essenciality of linoleic and alpha-linolenic acids, due to its metabolic importance.

Child, Preschool↗
PubMed1992

[Metabolism of trace elements in healthy and sick children. I. Health status].

The oligo-elements or trace elements have acquired a major importance in the knowledge concerning corporal composition and in the comprehension of their metabolic participation in organic processes. Today, thanks to the technological and scientific progress reached by modern pediatrics, the studies made at cellular level have advanced to a molecular level, which will in the future be, without doubt, the bridge that will lead into the atomic level. In addition, this review will briefly summarize several facts of the knowledge accumulated up to now, regarding: 1. The nutritional aspects of these oligo-elements; 2. Its biological functions in healthy condition, especially in children; 3. Their respective nutritional requirements.

Age Factors↗
PubMed1992

[Trace element metabolism in healthy and sick children. II. The disease state].

In the last 3 decades, the discovery of importance of trace elements in structure and functions of many enzymes, provided a tremendous impetus for research on the physiopathology, metabolism, clinical pharmacology and toxicology of these micronutrients in human beings, specially, in children. This paper presents recent information on various pathological inherited and acquired conditions, with abnormal nutritional status in children, due either to deficiency or excess of some oligo-elements. The general aspects of abnormal metabolism, physiopathology, and some specific clinical features, are described.

Child↗
PubMed1986

Metabolic adaptation in protein-energy malnutrition.

The metabolic response to chronic undernutrition covers a wide spectrum that ranges from decreased growth velocity in mild cases to profound distortion of body silhouette and composition and functional derangements in advanced stages of the protein-energy malnutrition-infection complex. A wide gamut of molecular, enzymatic, and hormonal processes assure a temporary availability of endogenous nutrients and the maintenance of vital functions.

Adrenal Cortex Hormones↗
PubMed1986

The functional response to furosemide in a case of de Toni-Debre-Fanconi disease.

The case of a 13-year-old boy with the advanced clinical picture of the idiopathic DeToni-Debré-Fanconi syndrome is described, on whom acute studies of proximal tubular functions and of the effect of furosemide thereon were performed. Sodium bicarbonate loading corrected the hyperchloremic acidosis, but induced an increase of urinary bicarbonate loss of over 20% of the filtered amount. Furosemide corrected bicarbonate reabsorption in spite of the presence of metabolic alkalosis. The urinary excretion of alpha-amino nitrogen, glucose, and phosphates decreased and tubular reabsorption of the two latter increased under furosemide. On a chronic treatment with furosemide and dietary sodium chloride restriction, correction of hyperchloremic acidosis, hypophosphatemia and rickets was achieved.

Adolescent↗
PubMed1979

"Hybrid" synapses formed by foreign innervation of parasympathetic neurons: a model for selectivity during competitive reinnervation.

Selectivity of synapse formation after nerve regeneration was tested in the parasympathetic cardiac ganglion of frogs (Rana pipiens). First, we tested the ability of somatic motor axons to establish synaptic connections with denervated ganglion cells by implanting the hypoglossus nerve into the vagotomized heart. After several weeks, stimulation of the implanted hypoglossus mediated a parasympathetic-like inhibition of the heart rate, and synaptic responses produced by hypoglossal stimulation were recorded intracellularly in ganglion cells. Light and electron microscopy indicated that implanted hypoglossal nerve terminals contacted parasympathetic ganglion cells only on their axons and not on the cell body (where most vagal synapses are found in control animals). Second, we tested whether regenerating vagal preganglionic axons would complete with foreign (hypoglossal) terminals for innervation of cardiac ganglion cells. We allowed the vagus nerve to regenerate in animals in which the implanted hypoglossus had established functional contacts with the cardiac ganglion. Vagal axons were able to reinnervate the heart and reestablish synaptic connections on the cell bodies of ganglion cells. Furthermore, functional transmission at the foriegn (hypoglossal) terminals disappeared concomitant with vagal reinnervation.

Animals↗
PubMed1978

[Post-natal growth of the child born with intra-uterine malnutrition].

Growth and morbidity were studied in a group of children at one and two years of age of which 10 were born with intrauterine malnutrition, 14 were prematures and nine had normal weight. All were evaluated , according to the Gesell test, at two years of age. Malnourished and premature children grew at greater rate than normals, reaching their size at one year of age. However, at the age of two, length of premature children was less than in normals. Gesell's test results were subnormal in 50 percent of the malnourished ones.

Age Factors↗
PubMed1978

[Changes in leucocyte metabolism during growth in children born with malnutrition].

Changes of energy metabolism in leucocytes have been studied longitudinally as well as cross-sectionally in three groups of children born: 1.- at term, with normal weight; 2.- with intra-uterine malnutrition; 3.- prematurely. The longitudinal study showed that, at birth, the activity of adenylate kinase as well as concentrations of ATP, ADP AND AMP were significantly lower in the malnourished than in the normal child. At one year of age, the values of enzyme activity are approximately equal in both groups, while the concentrations, of ATP and ADP are higher in malnourished children. Finally, at two years of age all values found, with the exception of AMP concentration, were higher in malnourished than in normal children born at term. In the data of the cross-sectional study this accelerated biochemical maturation is also shown.

Female↗
PubMed1977

[Chemotaxis and phagocytosis of polymorphonuclear leukocytes in malnourished children].

Chemotactic activity of neutrophil polimorphonuclear cells, liberation of chemotactic factors by plasma proteins and phagocytic function of PMN cells by nitroblue tetrazolium reaction were evaluated in 20 malnourished children (from grade 1 through grade III) and in 20 normal children with similar age and sex, without any apparent infection. Also quantitative determination of immunoglobulins A, G and M and C3 complement fraction concentration in serum was made. Chemotactic and phagocytic activity were normal. Serum levels of Igs and C3 complement were within the lower limits of the normal range.

Chemotaxis, Leukocyte↗
PubMed1976

The primate median eminence. II. Correlative high-voltage transmission electron microscopy.

The ultrastructure of the normal median eminence of the male rhesus monkey (Macaca mulatta) is described using high-voltage electron microscopy. Surface specializations of ependymal cells lining the infundibular recess included cilia, apical extrusions, and microvilli. Supraependymal cells were predominantly macrophage-like, but examples of lymphocytic types were also seen. Tanycytes had long, branching, basal processes filled with numerous microtubules, some lipid droplets, and granules. The zona interna was composed of large unmyelinated neurosecretory fibers. A few myelinated fibers were also seen, but their character as neurosecretory fibers could not be established. The zona externa was composed of densely-packed profiles of neuro secretory fibers of small diameter, was well-vascularized and contained the terminations of tanycytes. Perivascular glial cells, vesiculated elements, pituicytes, and cellular elements common to connective tissue were observed. The intricate relationships between both the cellular and fibrous elements of the median eminence can be appreciated with the capability of high-voltage electron microscopy to discern ultrastructure in sections 10 times thicker than those used for low-voltage electron microscopy. The median eminence of this primate species has an ultrastructural organization similar to that described for most other species.

Animals↗
PubMed1976

[Diffusible blood calcium in children with advanced protein energy malnutrition].

A previous study had shown that in children with third degree protein-energy malnutrition, ultrafilterable or diffusible serum calcium concentrations remain normal, while the protein-bound fraction is low in those with hypoalbuminemia, accounting for over-all hypocalcemia. In order to retest those findings, a new series consisting of 20 small marasmic infants and 16 children with kwashiorkor was studied, using a membrane ultrafiltration procedure. Fifteen eutrophic children served as controls. At time of their admission into hospital, both groups of patients showed hypocalcemia, more so the cases of kwashiorkor. Diffusible calcium was normal, while the protein-bound moiety was significantly decreased in children with kwashiorkor. Upon recovery, protein-bound as well as total calcium concentrations returned to normal values.

Blood Proteins↗