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Biomedical subjects

R Ramos-Zepeda

Publications and source records attributed to R Ramos-Zepeda.

9 recordsLinked to original sources
PubMed1991

Increased phagocytic activity of peripheral blood monocytes after intravenous injection of phospholipase A2 to monkeys.

One of the expressions of the activity of phagocytic cells such as monocytes or macrophages is a burst of increased oxidative activity on stimulation. The free oxygen radicals liberated, mainly O2- and H2O2, lead to chemoluminescence, which is thus a measure of activation. Chemoluminescence also depends on arachidonic acid metabolism, and this depends on phospholipase A2 (PLA2). We modified monocyte activity in monkeys by injecting them i.v. with this enzyme and observed that 30 min after injection, the phagocytic activity of peripheral blood monocytes and the chemoluminescence they emitted was greater than that of controls. We suggest that PLA2 may act as an in vivo immunomodulator in mammals.

Adjuvants, Immunologic↗
PubMed1990

Increased adenosine deaminase activity in a patient with cartilage-hair hypoplasia.

A boy aged 9 years presenting short stature and recurrent respiratory-tract infections was studied. The clinical and roentgenological pictures allowed the diagnosis of cartilage-hair hypoplasia (metaphyseal chondrodysplasia, McKusick type). Biochemical studies disclosed a four-fold increase in adenosine deaminase activity, but without evidence of anemia. Immunological evaluation showed abnormal cellular but normal humoral immunity.

Abnormalities, Multiple↗
PubMed1986

Metabolic activity of phagocytes in experimental sporotrichosis.

Phagocytosis plays an important role as a protective mechanism against infections, since polymorphonuclear leukocytes (PMN) and macrophages are the first cellular lines opposed to aggressive microorganisms. In patients with sporotrichosis a diminished capability of killing engulfed yeast by their PMN has been described, but the origin of this deficiency remains unknown. In this work, partial aspects of the oxidative metabolism of PMN leukocytes and peritoneal macrophages of mongolian gerbils experimentally infected with sporotrichosis were studied. For this purpose the nitroblue tetrazolium (NBT) test as described by Baehner and Nathan (1) and myeloperoxidase activity measured according to Kaplow's method were utilized. The PMN and macrophages of mongolian gerbils infected with sporotrichosis showed increased reduction of NBT when compared with the phagocytic cells of normal ones, as is usually observed in most infections. Myeloperoxidase activity was diminished in both PMN and macrophages, but this diminution was statistically significant only in PMN leukocytes. These results show that part of the oxidative mechanisms of phagocytic cells can be impaired in experimental sporotrichosis, and could be correlated with the diminished fungicidal activity of PMN leukocytes obtained from patients infected with sporotrichosis.

Animals↗
PubMed1986

Bloom syndrome in a Mexican mestizo girl.

A 3-year-old girl with Bloom syndrome is described. She exhibited stunted growth of prenatal onset and defective immunity, but the typical skin manifestations were absent. Cytogenetic analysis revealed a 46,XX complement, 12.2% of metaphases with at least a structural aberration, and a ten-fold increase in the sister-chromatid exchange rate. Leukocyte beta-glucuronidase activity was reduced to about 1/3; the significance of this finding is not clear. The present observation demonstrates the variable expression of the disorder probably depending on ethnic and constitutional factors.

Bloom Syndrome↗
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↗
PubMedDate not supplied

[Formation of E-rosettes in homozygous nude mice (nu/nu) and heterozygotes (nu/+)].

Nude homozygote nu/nu mice show a deficiency in their cellular immune response, due to the fact that their thymic tissue is very scarce. The purpose of this paper has been to determine whether nu/nu mice, in the presence of T lymphocytes, have the capacity of forming E rosettes with sheep erythrocytes. These mice do present them, although in significantly lower quantities when compared to the nu/+ and normal ones of Balb/c strain. This result confirms previous information which point towards the existence of other types of markers on the surface of T lymphocytes in nu/nu mice.

Animals↗
PubMedDate not supplied

[Phagocytic activity in PMN leukocytes and macrophages of athymic nu/nu mice].

The athymic nu/nu mice represent a natural model for studying defense mechanisms. This study had the object of evaluating the phagocytic activity of polymorphonuclear leucocytes (PMN) and peritoneal macrophages (PM) in congenitally athymic homozygotic nu/nu mice. The results showed that the chemotaxis, random mobility, ingestion of latex particles and reduction of nitroblue tetrazolium were all normal. Nevertheless, the enzyme myeloperoxidase in the PMN was significantly diminished when compared with Balb/c mice. These results suggest a partial decrease in the oxidative metabolism of the PMN in nu/nu mice.

Animals↗