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Biomedical subjects

L Sen

Publications and source records attributed to L Sen.

At least 73 records · Page 4Linked to original sources
PubMed1986

Autologous rosette forming cells in subjects at risk for the acquired immunodeficiency syndrome.

We investigated the distribution of autologous rosette forming cells (ARFC) in the peripheral blood from subjects at risk for the acquired immunodeficiency syndrome (AIDS). The mean percentage of ARFC with autologous plasma from 35 male homosexual individuals was significantly lower than that of 31 normal controls. The mean percentage of ARFC of SARA had a direct linear correlation with the percentage of T4+ cells (p less than 0.01). Within the SARA group, those with antibodies against HTLV-III/LAV had percentages of ARFC significantly lower than SARA with negative antibodies. Plasma from SARA decreased the percentage of ARFC of normal cells when compared to normal homologous plasma (p less than 0.005), whereas normal homologous plasma did not modify the low percentage of ARFC from SARA. These results indicate that SARA possess a depletion of this subpopulation of T cells. This is more pronounced in subjects with anti-HTLV-III/LAV antibodies. The low ARFC is related to a decrease in the number of cells that correlates with the number of T4+ cells. The inhibition of normal ARFC by plasma from SARA suggests the existence of plasma factors that could mask the lymphocyte receptors for their own red blood cells and/or coat erythrocytes preventing lymphocyte-erythrocyte binding.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Acute lymphoblastic leukemia in Argentina. Relationship between surface markers and prognosis.

Leukemic blasts from patients with acute lymphoblastic leukemia (ALL) were tested initially for the following surface markers: sheep erythrocyte receptors at 4 degrees C and 37 degrees C; receptor for the C3 fraction of complement; mouse erythrocyte receptor; and surface immunoglobulins. We found that 73% of the ALL were devoid of these markers, 9% had C3 receptor only, 2% were B-ALL, and 15% were T-ALL. Only one of 147 cases tested expressed receptors for mouse erythrocyte receptor. C3-ALL predominated in girls and the prognosis was similar to that of the ALL devoid of markers. T-ALL was associated with some high-risk factors, such as high initial leukocyte counts, and a predominance in boys older than 5 years of age. Further studies were done in which cytoplasmic immunoglobulins were evaluated and surface antigens were identified by the following monoclonal antibodies: OKT1, OKT3, OKT4, OKT6, OKT8, OKT9, OKT10, OKT11a, OKIa1, and J5 (anti-CALLA). Less than 1% were B-All, 15% were T-ALL, and approximately 85% were non-T, non-B ALL. Of the latter group, 69% were common-ALL, 16% were pre-B ALL, and 15% were null-ALL. Within the T-ALL, the expression of the T antigenic mosaic was heterogeneous. Results by a multivariate analysis demonstrated that sex, age, initial leukocyte count, and T-cell phenotype were independent variables with a negative prognostic value (p less than 0.01), and the only combination with significant interaction was between T-cell phenotype and leukocyte counts.

Antibodies, Monoclonal↗
PubMed1986

Early defect of phagocytic cell function in subjects at risk for acquired immunodeficiency syndrome.

We studied the functions of peripheral blood monocytes and polymorphonuclear cells in 15 apparently healthy homosexual men, eight homosexual or bisexual subjects with unexplained generalized lymphadenopathies (pre-AIDS), four homosexual men with acquired immunodeficiency syndrome (AIDS), and 15 heterosexual men. In comparison with normal controls, the homosexual groups studied presented a decreased monocyte candidacidal activity for Candida pseudotropicalis that gradually deteriorates as the clinical symptoms progress towards AIDS. The monocyte phagocytic function was retained. Although the phagocytic and candidacidal activities of the polymorphonuclear cells did not differ from those of the normal controls, the candidacidal activity in some of the cases studied was unusually enhanced, indicating that the cells were in an activated state. In addition, only two of nine sera tested from asymptomatic homosexual males were positive for antibodies to HTLV-III/LAV, while six out of eight pre-AIDS and both of the two AIDS patients tested had antibodies to AIDS-associated retrovirus. We suggest that in AIDS the phagocytic system is already involved, together with B and T lymphocyte abnormalities, during the early events of the syndrome, even without the detection of AIDS-associated retrovirus antibodies.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Impairment of natural killer (NK) function in carriers and patients with thalassemia major.

To evaluate natural killer cytotoxicity (NKC) and its regulation by interferon (IFN) in thalassemia major (TM), we studied 19 patients, 10 carriers (parents of 10 different patients) and 35 normal subjects (children and adults) as controls. We have found a diminished NKC, as well as a decrease in the percentages of cells bearing IgGFc receptors in TM patients, whereas they were normal in TM carriers. Although alpha-IFN enhanced NKC in TM patients and carriers, Con A (an IFN inducer) had no enhancing effect on NKC from either patients or carriers. These agents did not modify the expression of IgGFc receptors in cells from TM patients, carriers or normal controls. Our results indicate that TM patients have a defect in NK cell maturation or activation, which is reversed by alpha-IFN. The failure of TM patients and carriers to respond to Con A suggests a defect in NKC regulation which might be related to a genetic origin.

Adolescent↗
PubMed1986

Progressive dysfunction of monocytes associated with iron overload and age in patients with thalassemia major.

We evaluated phagocytic and lytic activities of peripheral blood monocytes (PBMo) from patients with thalassemia major (ThP) using C pseudotropicalis as the target. PBMo from ThP showed decreased lytic activity (P less than .001), whereas the phagocytic activity did not differ from that of the controls. Significant inverse correlations were found between lytic activity of PBMo and age of patients (r2 = .47; P less than .01) and also between lytic activity and serum ferritin levels (r2 = .65; P less than .001). No association was found between lytic activity and other variables (blood transfusion regimens, therapy with desferrioxamine, liver damage, and the presence of sHBAg). Splenectomy showed no positive effect on PBMo functions from ThP. Our results suggest that PBMo from ThP have an intracellular defect in their microbicidal mechanisms associated with iron overload. This cell dysfunction could be responsible, at least in part, for the increased susceptibility to infections reported in ThP.

Adolescent↗
PubMed1985

Normalization of monocyte candidacidal deficiency by cyclooxygenase inhibitors in Hodgkin's disease.

In a previous work, the authors found that the peripheral blood monocytes from patients with Hodgkin's disease (HD) had depressed lytic capability to kill Candida pseudotropicalis and depressed phagocytic function. The aim of this study was to evaluate if cyclooxygenase inhibitors could correct the defective macrophage functions. Fifteen untreated patients with HD and 10 normal subjects were studied. The incubation of the cells from the patients with HD with indomethacin (IM) at 1, 3, and 10 micrograms/ml and with acetylsalicylic acid (ASA) at 20 micrograms/ml increased their previously deficient ability to kill C. pseudotropicalis, reaching values close to those of normal subjects. The oral administration of ASA during 1 week also corrected the monocyte lytic deficiency in the patients' group. Neither the in vitro nor the in vivo treatment with these cyclooxygenase inhibitors had any significant effect on normal subjects' monocytes' lytic function. The drugs did not improve the impaired phagocytic function in patients with HD. These results indicate that the failure of the lytic activity of the monocytes in HD could be associated to an excessive production of PGE2, and the oral administration of inhibitors of the cyclooxygenase activity can correct such abnormality whereas the phagocytic dysfunction is not reverted by them.

Adolescent↗
PubMed1985

Cytogenetic and immunologic phenotype findings in Hodgkin's disease.

There are very few chromosome studies using banding techniques of lymph nodes in Hodgkin's disease (HD), and determinations of immunologic phenotypes are scarce. We have performed both cytogenetic and immunologic studies in 12 of 22 lymph node biopsies of different histologic types obtained from 20 HD patients (no mitotic cells were found in the remaining ten lymph nodes). A near-diploid modal number was obtained in 80% of the cases, and 20% showed a bimodal distribution. Clones were observed in 50% of HD lymph nodes, with chromosome markers in 60% of them. Markers 15q+, 5p-, and der(X) and a trisomy of chromosome #21 were observed in our cases. Seventy-one percent of the lymph nodes studied showed a predominance of T lymphocytes. Within the lymph nodes, where the karyotype was determined, 4/12 lymph nodes presented a predominance of B lymphocytes, and they were all included in the group with structural chromosome abnormalities.

Adult↗
PubMed1985

Inhibition of E-and EAC-rosette formation by gentamicin, ampicillin and tetracycline.

The determination of the absolute number of cells with receptors for sheep erythrocytes and for C3 by rosette techniques are usual clinical tests in the evaluation of the lymphoid populations in different diseases. Antibiotics are commonly added to avoid contamination in the reagents employed in the rosetting studies, as well as in "in vitro" tests of lymphocytes function and in cultures of cell lines. In this study we have established the influence of gentamicin (G), demeclocycline hydrochloride (DH) and ampicillin (A) on the membrane receptors, through their effect on E4 degrees C and EAC formation. We found that in the presence of each of the three antibiotics there was a partial inhibition of both rosettes. The inhibition was found to be dose related, gentamicin concentrations of 85 micrograms/ml and 42,5 micrograms/ml resulting in significant reduction of E4 degrees C and EAC rosettes respectively. Studies with A and DH indicated that EAC rosettes were inhibited by both drugs after incubation times of at least 15 minutes, while a minimum of 30 minutes of incubation was required to attain significant inhibition of E4 degrees C rosettes. These results indicate that the C3 receptors would be more sensitive to the action of these antibiotics than the receptors for sheep erythrocytes.

Ampicillin↗
PubMed1985

Monoclonal B-cell lymphocytosis in early childhood. A case report.

A case is reported of a 12-year-old girl with a benign course of a lymphocytosis through years associated with splenomegaly. The lymphocytes simultaneously expressed a monoclonal B-cell phenotype of IgM-kappa and a mature T-antigen using the monoclonal OKT1 antibody. Due to her stable condition, no treatment was required. The immunological results suggest the possibility of an early childhood B-cell chronic lymphoid leukemia.

Antibodies, Monoclonal↗
PubMed1984

[Visualization of specific leukocyte granules using morin and other fluorochromes].

The visualization of the specific granulation of leukocytes is useful in hematology to identify de cell type in leukemic diseases. The authors employed the acidic fluorochrome morin after testing its high affinity for the fluorescent reaction with morin in human and chicken peripheral blood smears, and in streak smears from rabbit spleen. The best results were obtained with a solution prepared either with 0.10 mg morin per ml of 50 per 100 ethanol, or with a saturated solution of morin in distilled water diluted to one fourth in 25 per 100 ethanol. When observed under blue-violet excited light (436 nm) the acidophilic granules of leukocytes produce a bright yellow fluorescence, while the cell nuclei show a faint greenish fluorescence. As for the mechanism of the reaction, it consists possibly in an interaction between morin and the basic components of the granules. Other acidic fluorochromes, as primulin and hematoxylin, produce similar fluorescent reactions with the acidophilic granules.

Animals↗