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Biomedical subjects

M de la Fuente

Publications and source records attributed to M de la Fuente.

At least 19 recordsLinked to original sources
PubMed1992

Changes with aging and physical exercise in ascorbic acid content and proliferative response of murine lymphocytes.

Ascorbic acid content and lymphoproliferative response to phytohemagglutinin were measured in lymphocytes from axillary nodes, spleen and thymus of young (15 +/- 2 weeks) and old (60 +/- 5 weeks) BALB/c mice. Ascorbic acid content in lymphocytes from spleen and thymus was found to be significantly higher and the lymphoproliferative response in the three immunocompetent organs significantly lower in old mice as compared to young mice. Moreover, young and old BALB/c mice were required to maintain a swimming activity until exhaustion (exhaustive exercise) or 90 min of swimming each day for a total of 20 days (continuous exercise). In both young and old mice the stress produced by exhaustive exercise and confirmed by the existence in serum of significantly increased levels of corticosterone compared to controls, caused a significant decrease in ascorbic acid content as well as in lymphoproliferative response. Continuous exercise, characterized by the presence in serum of significantly decreased levels of corticosterone compared to controls, produced the most significant decrease in ascorbic acid content from young and old murine lymphocytes. Moreover, this exercise resulted in a significant increase in lymphoproliferative response. Our results suggest that aging results in an increase in the ascorbic acid content of lymphocytes accompanied by a decline in the lymphoproliferative response in old BALB/c mice.

Aging↗
PubMed1992

Impairment of phagocytic process in macrophages from young and old mice by protein malnutrition.

In young (15 +/- 2 weeks old) and old (75 +/- 5 weeks old) Swiss mice fed a 4% protein diet ad libitum for 15 days, we studied the different steps of phagocytic processes of peritoneal macrophages. In young mice, adherence to tissue substrates was significantly increased, but spontaneous mobility, chemotaxis, attachment and ingestion of opsonized Candida albicans, and production of superoxide anion indicative of microbicidal capacity measured by the nitroblue tetrazolium (NBT) reduction were significantly decreased with respect to the corresponding young controls (mice fed with a standard 17% protein diet). Attachment and ingestion of C. albicans, and NBT reduction were also decreased in old protein-malnourished mice.

Aging↗
PubMed1991

Effects of imipenem and cefmetazol on lymphocyte receptors CD2, Fc and C3b of complement.

We studied the influence of Imipenem and Cefmetazol (50 mg/l) on lymphocyte receptors CD2, Fc and C3b of complement. The lymphocytes were obtained from human blood and mice axillary ganglions. Cefmetazol significantly increases the binding capacity of human lymphocyte receptors CD2 to sheep red blood cells while Imipenem does not alter this binding. The number of Fc lymphocyte receptors for the constant fraction of IgG is found to be significantly increased when the lymphocytes are incubated in vitro with Imipenem and Cefmetazol. When the lymphocytes are treated with these antibiotics there is an increase in the receptors capable of binding to fraction C3b of the complement.

Animals↗
PubMed1991

Stimulation of phagocytic processes and antibody-dependent cellular cytotoxicity of human neutrophils by cefmetazole.

Interactions between antimicrobial agents and phagocytic cells, especially neutrophils, have a potential role in the treatment of infections. The in vitro effects of cefmetazole, a novel beta-lactam antibiotic, at a therapeutic concentration reached in plasma (50 micrograms/ml) on phagocytic and cytotoxic functions of human neutrophils have been studied. In human neutrophils, adherence capacity to nylon fiber and to substrate, chemotaxis, attachment to and ingestion of Candida albicans (with serum, with decomplemented serum and without serum), ingestion of inert particles (latex beads), candidicidal activity and superoxide anion production were all stimulated by cefmetazole. Cefmetazole at this dose was a chemotactic agent for neutrophils. Antibody-dependent cellular cytotoxicity (ADCC) was also increased by this anti-microbial agent.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1991

[Experience of the National Autonomous Board for Certification of Medical Specialties].

After 6 years of operation of a National (autonomous) Board for Certification of Medical Specialists, the number, distribution and training of medical specialists is analyzed. Problems regarding significant differences in the quality of training and imbalance among different specialties are identified. The medical profession has expressed its confidence and feels supported by the activities of the Board. However, health care deliverers and users in general are expected to increase their support and consideration for the information provided by the Board, in order to fulfill the purpose for which it was established.

Chile↗
PubMed1990

Phagocytic function and antibody-dependent cellular cytotoxicity of human neutrophils in the presence of N-formimidoyl thienamycin.

The efficacy of an antibiotic in the treatment of bacterial infections depends upon the interactions of the drug, bacteria and phagocytes. We have studied "in vitro" the effect of N-formimidoyl thienamycin (Imipenem), a novel beta-lactamic antibiotic, on the phagocytic function and antibody-dependent cellular cytotoxicity of human neutrophil leukocytes. The incubation of these cells with 50 micrograms/ml of Imipenem similar to the therapeutic levels reached in plasma results in an increase of their adherence capacity to nylon fiber and to substrate, induced mobility or chemotaxis, opsonization, phagocytosis of Candida albicans (with serum, with decomplementarized serum and without serum) and latex beads, candidicidal power and the capacity of NBT reduction. Imipenem at this dose also presents chemoattractant power for neutrophils and enhances the antibody-dependent cellular cytotoxicity (ADCC).

Antibody-Dependent Cell Cytotoxicity↗
PubMed1990

Changes in the phagocytic function of peritoneal macrophages from old mice after strenuous physical exercise.

The effect of acute physical exercise (swimming until exhaustion) on the phagocytic function of peritoneal macrophages from old adult BALB/c mice (55 +/- 5 weeks old) was studied. Adherence capacity of macrophages to substrate, spontaneous mobility and chemotaxis as well as digestion capacity measured by nitroblue tetrazolium (NBT) reduction in presence of ingested material (latex beads) were not modified with exercise. Adherence to nylon fiber, opsonization and ingestion of Candida albicans (either spontaneous or in presence of serum), ingestion of latex particles as well as nitroblue tetrazolium (NBT) reduction in absence of ingested material (oxidative metabolism measure) were increased in respect to controls with statistically significant differences (P less than 0.001) in peritoneal macrophages after the exercise.

Aging↗
PubMed1990

Changes in growth hormone secretion in spontaneously hypertensive rats.

Secretion of the growth hormone (GH) in spontaneously hypertensive (SH) male rats has been determined and compared with that of normotensive Wistar-Kyoto (WKY) controls. In a first set of experiments, plasma GH concentration and pituitary GH content were measured in SH rats 30, 60 and 90 days old. 30-day rats showed reduced GH plasma and pituitary levels, whereas in 60- and 90-day-old rat no differences in GH plasma concentration and increased GH pituitary content were observed. In a second set of experiments, 90-day-old SH male rats anesthetized with sodium pentobarbital and intravenously injected with growth hormone-releasing factor (GRF) showed an amplitude and duration of response to injected hormone higher than WKY controls. In a third set of experiments, hemipituitaries of 90-day-old SH males were incubated for 2 h in Krebs-Ringer-bicarbonate either in the presence or in the absence of GRF. In the absence of GRF stimulation, the in vitro release of GH was higher than in WKY controls, whereas in the presence of GRF the sensitivity and the maximum response to GRF was reduced in comparison with normotensive male rats. These results indicate that SH rats have decreased pituitary content and plasma GH concentration before puberty. Besides, they showed increased pituitary GH content in adulthood and opposite changes in the in vivo and in vitro response to GRF.

Animals↗
PubMed1990

Effect of age, culture medium and lymphocyte presence on ascorbate content of peritoneal macrophages from mice and guinea pigs during phagocytosis.

Changes in ascorbate content have been measured by high-performance liquid chromatography in peritoneal macrophages from mice and guinea pigs stimulated by latex particles, in the presence and absence of peritoneal lymphocytes. There was a significant decrease in ascorbate content in murine macrophages 5 min after stimulation that did not occur in controls. The rate of ascorbate consumption was nearly identical with murine macrophages incubated in three different ascorbate-free culture media (phosphate-buffered saline, Hanks' solution and RPMI) studied, as well as with macrophages from young and old mice. In contrast to mice, both control and stimulated peritoneal macrophages from guinea pigs showed significant decreased contents of ascorbate in the absence of lymphocytes compared with those in the presence of lymphocytes. Moreover, stimulated macrophages showed significantly decreased ascorbate contents with respect to controls. These results indicate that ascorbic acid plays an important role in macrophages and that peritoneal lymphocytes also seem to play a significant role in the maintenance of ascorbate content in macrophages during phagocytosis in guinea pigs.

Age Factors↗
PubMed1990

[Nontraumatic deaths associated with a natural catastrophe. The experience of the earthquake in Chile 1985].

We analyzed causes of death before and after the March 1985 earthquake in Valparaíso, Chile. Causes of death were obtained from death certificates. Apart from death directly due to trauma during the earthquake, a significant increase was observed in deaths due to accidents (+51), cardiovascular disease (+38), malnutrition (+13) and psychiatric disorders (+13). Retired males over age 65 were most affected.

Adolescent↗
PubMed1990

Changes in the number of leukocytes and lymphocyte subpopulations induced by exercise in sedentary young people.

The influence of physical exercise on the quantification of leukocytes and lymphocyte subpopulations has been studied. These cells were obtained from blood taken from eleven healthy young men and women who follow a sedentary life style, before and after vigorous exercise (running). The results indicate that physical activity increases the number of white blood cells and the concentrations of circulating lymphocytes. The proportion of T-lymphocytes, estimated as rosette forming cells with sheep red blood cells after cold incubation, is constant, whereas a corresponding increase in cells with receptors for C3b or Ig-Fc is also observed. The data indicate that physical activity leads to an irregular intravascular discharge in stored cells.

Adult↗
PubMed1989

Macrophage and lymphocyte antibody-dependent cellular cytotoxicity in spontaneous leukemogenesis of AKR/J mice.

Antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by peritoneal macrophages and splenic lymphocytes was studied in young (15 weeks) and old (45 +/- 5 weeks) preleukemic AKR/J mice and leukemic (55 +/- 5 weeks) AKR/J mice. This strain spontaneously develops a virally induced T cell leukemia-lymphoma between the ages of 32 and 48 weeks. The peritoneal macrophages from the AKR/J leukemic and old preleukemic mice showed an impaired ADCC when compared with their respective age and tumor-free BALB/c controls and with young preleukemic AKR/J mice. Young and old preleukemic AKR/J mice and their respective controls had similar ADCC values with respect to splenic lymphocytes, whereas an impaired ADCC was observed by the splenic cells from leukemic AKR/J mice. The possibility of using ADCC mediated by macrophages as a test to detect the onset of the leukemic process is discussed.

Animals↗
PubMed1989

[Smoking among elementary school children. Study in a population of low socioeconomic level].

We surveyed a probabilistic sample of 1383 school children attending elementary school (5th to 8th grade) in La Pincoya, a neighborhood of northern Santiago. 53.7% had smoked at least once, and 1 out of 5 were regular smokers of 1-4 cigarettes (72%) or more than 5 cigarettes a day (14%). The incidence of smoking was higher among boys and increased with age. Smoking occurs in different places including the street (19%). About 60% of children get their cigarettes from other children or adults. Those who buy, do so by units rather than packs. The incidence of smoking raised to 64% among children of parents who smoked. Pleasure or imitation were quoted as main reasons for smoking.

Adolescent↗
PubMed1988

Enzymes of mannose metabolism in murine and human lymphocytic leukaemia.

Mannose in animal cells is phosphorylated by hexokinase (HK) and later isomerised by mannose phosphate isomerase (MPI) to fructose-6-P, which is incorporated in the glycolysis pathway. In this paper we report a significant decrease of MPI activity in splenic lymphoid cells from AKR/J old mice with lymphocytic leukaemia in comparison to that found in splenic lymphocytes from AKR/J non-leukaemic young mice and BALB/c young and old control mice. However, HK with mannose as substrate presents a normal activity in AKR/J leukaemic mice. This marked shortage of MPI explains the in vitro mannose toxicity found by us here in splenic lymphoid cells from AKR/J leukaemic mice. MPI activity was also decreased in peripheral blood lymphocytes from 4 out of the 6 patients studied with chronic lymphocytic leukaemia in relation to the activity found in the lymphocytes from healthy donors. The utility of analysing MPI activity in leukaemia patients and the use of mannose as an innocuous chemotherapic supporting agent in patients with decreased MPI activity is proposed.

Animals↗