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Biomedical subjects

J Muñoz

Publications and source records attributed to J Muñoz.

At least 217 records · Page 12Linked to original sources
PubMed1981

Polyclonal activation of human peripheral blood B lymphocytes by formaldehyde-fixed Salmonella paratyphi B. I. Immunoglobulin production without DNA synthesis.

A "new" polyclonal activator of human peripheral blood B cells, formaldehyde-fixed Salmonella paratyphi B, is described. This bacterium does not stimulate cell proliferation as measured by incorporation of tritiated thymidine but does stimulate a subpopulation of B cells to secrete large amounts of IgM, IgG, and IgA in 7-day cell cultures. The immunoglobulins (Ig) produced by cells responding to S. paratyphi B are not specific antibodies against the bacterial antigens. In comparison with other B cell activators (pokeweed mitogen, Staphylococcus aureus Cowan I, and lipopolysaccharide), S. paratyphi B stimulation produced greater amounts of IgM but less IgG than pokeweed mitogen (PWM) or S. aureus Cowan I; lipopolysaccharide failed to stimulate significant Ig production on day 7 in most cases. In addition, the response to S. paratyphi apparently did not require T cell collaboration. These results suggest that the B cell subpopulation(s) responding to S. paratyphi B may be more differentiated B cells than those responding to either PWM or S. aureus Cowan I. Peripheral blood mononuclear cells from five patients with common variable immunodeficiency without evidence of abnormal suppressor T cells or monocytes failed to respond to S. paratyphi B, whereas cells from two of the same patients responded well to S. aureus Cowan I and partially to PWM. Thus, S. paratyphi B appears to be superior to other B cell activators for studies of B cell function in normal and abnormal states.

B-Lymphocytes↗
PubMed1980

Induction and suppression of immunoglobulin synthesis in cultures of human lymphocytes: effects of pokeweed mitogen and Staphylococcus aureus Cowan I.

The synthesis and secretion of immunoglobulins by human peripheral blood mononuclear cells in cultures stimulated with pokeweed mitogen or Staphylococcus aureus Cowan I were evaluated by enumeration of cells containing cytoplasmic immunoglobulins and cells actively secreting immunoglobulins, and by quantitation of immunoglobulins released into culture supernatants. The two mitogens caused comparable stimulation of immunoglobulin production; however, in contrast to pokeweed mitogen, S. aureus was active in cultures depleted of T lymphocytes, and its stimulatory effects were resistant to the influence of suppressor T cells generated by co-stimulation with concanavalin A or by preincubation without mitogenic stimulus. These results indicate distinct pathways of induction and suppression of immunoglobulin synthesis for these two polyclonal B cell activators, and suggest that stimulation by S. aureus is less thymus dependent than that induced by pokeweed mitogen.

Aging↗
PubMed1980

Measurements of extracellular immunoglobulins as an index of B cell function.

We have developed a method for measuring the activation or suppression of B cells in culture by determination of immunoglobulins released into the extracellular fluid, using a conventional, nonisotopic assay. To avoid the interference of human serum proteins in the assays, cultures were established in medium supplemented with fetal calf serum. This caused some B cell activation, as reflected by the release of small amounts of immunoglobulins (1.5 to 0.7 microgram/ml IgG, 0.8 to 1.4 microgram/ml IgA, 0.6 to 0.7 microgram/ml IgM on day 7), but pokeweed mitogen stimulation resulted in the release of substantially larger amounts of immunoglobulins (8.2 to 4.6 microgram/ml IgG, 3.8 to 2.9 microgram/ml IgA, 8.0 to 4.0 microgram/ml IgM on day 7). Stimulation with Staphylococcus aureus (Cowan I) also resulted in release of immunoglobulins, with somewhat higher levels of IgM, and the release was inhibited by a suppressive substance obtained from Streptococcus intermedius. Time-course curves for immunoglobulin production by cultures stimulated with pokeweed mitogen and S. aureus showed interesting individual variations, but in general the levels began to rise consistently by day 4 or 5 and maximum levels were reached by day 7. These studies show that determination of extracellular immunoglobulins can be used as an index of B cells activation in routine studies.

B-Lymphocytes↗
PubMed1979

Assay of immunoglobulins in supernatants of lymphoid cell lines by conventional laser nephelometry.

An adaptation of the nephelometric assay for serum immunoglobulins has been developed for detection and quantitation of extracellular immunoglobulins in cultures of lymphoblastoid cell lines. This assay employs the standard equipment for laser nephelometry and commercial reagents for immunoglobulin quantitation. By adjusting dilutions of controls and sample volumes of culture supernatants, amounts of IgG and IgM below 1 microgram/ml can be detected in culture supernatants. At concentrations between 1 and 4 microgram/ml, day-to-day and within-run variations for IgM assays were 16 and 11% respectively. The possibility of measuring immunoglobulins secreted by cell lines by conventional laser nephelometry opens several areas of application in the study of the functional activity of B cells and of cell-cell interactions.

B-Lymphocytes↗
PubMed1976

Gastric cancer in Colombia. II. Case-control epidemiologic study of precursor lesions.

Endoscopic surveys in the Department of Narino (Colombia) showed that natives of areas of very high risks for stomach cancer have a higher prevalence of atrophic gastritis and intestinal metaplasia than do persons born in other parts of Narino. In these surveys, diets were compared between individuals with and without evidence of these suspect precursor lesions of stomach cancer and between individuals born in the areas designated as high and low risk for stomach cancer. The composite evidence from the comparisons indicated lettuce to be negatively associated with stomach cancer and raised the possibility to a positive association for corn. The relationship of these findings to other epidemiologic evidence and the implications for applying the epidemiology of stomach cancer to the epidemiology of precursor lesions were examined.

ABO Blood-Group System↗
PubMed1976

[Comparative investigations in closing nephrotomies with conventional suturing technique and dura ribbons (author's transl)].

On 13 rabbits total longitudinal nephrotomies were performed on both kidneys. On the right side the margins of the parenchyma were sutured together with figure eight sutures. On the left, the nephrotomies were closed by tying ribbons of human dura around the kidney. Excretory urograms after 4-8 months showed no differences on both sides. On histological examination there was no difference of the scars. After roentgenological and histological criteria there are no advantages by closing kidney wounds with dura ribbons versus conventional suturing technique.

Animals↗
PubMed1976

A new method for detection and localization of urinary infection. The fluorescence antibody test.

The urinary sediment of 56 patients with active urinary infection were studied through a direct immunofluorescence technique in order to detect the presence of antibody-coated bacteria. In 35-36 pyelonephritis cases the results were positive. However, in 11 cases with lower urinary infection there was no sign of antibody coasted bacteria. A pathological intravenous pyelogram (IVP) was obtained from 33 pyelonephritic cases. In the flurorescent antibody (FA) test was positive, one was negative. In the remaining three pyelonephritic cases the IVP was normal the the FA test positive. In these three cases, cystography revealed the presence of ureterovesical backflow. A good statistical correlation was obtained by comparing the positive results of the test with the titer of serum antibody against the bacteria causing the infection. We have introduced some variation to the original method which permits simpler administration of this test to ambulatory patients and increases the diagnostic possibility of those cases of bacteriuria less than 100,000 bacteria/ml.

Acute Disease↗
PubMed1976

A new method for detection and localization of urinary infection: the fluorescence antibody test.

The urinary sediment of 56 patients with active urinary infection were studied through a direct immunofluorescence technique in order to detect the presence of antibody-coated bacteria (ACB). In 35-36 pyelonephritis cases the results were positive. However, in 11 cases with lower urinary infection there was no sign of ACB. A pathological intravenous pyelogram (IVP) was obtained from 33 pyelonephritic cases. In 32 cases the fluorescent antibody (FA) test was positive, in one it was negative. In the remaining 3 pyelonephritic cases the IVP was normal and the FA test positive. In these 3 cases cystograph revealed presence of urethral-vesical backflow. A good statistical correlation was obtained by comparing the positive results of the test with the titer of sericeous antibody against the bacteria causing the infection. We have introduced some variations to the original method which permits simpler administration of this test to ambulatory patients and increases the diagnostic possibility of those cases of bacteriuria less than 100,000 bacteria/ml.

Antibodies, Bacterial↗
PubMedDate not supplied

Hepatosplenic large cell immunoblastic lymphoma in a bottlenose dolphin (Tursiops truncatus) with high levels of polychlorinated biphenyl congeners.

This report describes a large cell immunoblastic lymphoma in a bottlenose dolphin found stranded alive in Gran Canaria, Spain. Diffuse infiltration of round neoplastic cells was observed in the splenic cords and sinuses and in hepatic sinusoids, resulting in moderate organ enlargement. The tumour cells (immunophenotype IgG+ and CD3-) showed scant, lightly eosinophilic or basophilic cytoplasm, distinct cell boundaries and hyperchromatic nuclei, each with one or more nucleoli. Mitoses were common. On the basis of histopathological, immunohistochemical and ultrastructural features, the tumour was classified as an immunoblastic lymphoma. Eleven polychlorinated biphenyl (PCB) congeners, 23 organochlorine pesticides and 16 polycyclic aromatic hydrocarbons (PAHs) were detected in the blubber and liver. High concentrations of PCBs 153, 180, 138 and 187 found in the liver may have been associated with the hepatosplenic lymphoma.

Adipose Tissue↗
PubMedDate not supplied

Aged mice exhibit greater mortality concomitant to increased brain and plasma TNF-alpha levels following intracerebroventricular injection of lipopolysaccharide.

BACKGROUND: Age-related defects in the development of peripheral inflammatory responses have been observed in rodents and humans. OBJECTIVE: We examined the effects of age on a centrally injected endotoxin-induced cytokine production and cellular activation in mice. METHODS: Male C57BL/6J (B6) mice, C3H/HeN mice, and C3H/HeJ mice received an intracerebroventricular injection of lipopolysaccharide (LPS) and were sacrificed at various times (2, 4, 8 h) thereafter. ELISA for IL-1beta, IL-6, IL-12, and TNF-alpha were conducted on forebrain tissue homogenates as well as plasma samples, and lectin staining to detect activated microglia was prepared for selected brain slices. RESULTS: Intracerebroventricular injection of LPS in B6 mice produced an age-associated increase in mortality which was paralleled with a significant increase in brain and plasma levels of TNF-alpha. AntiTNF-alpha- and IL-6-immunoreactive cells possessed macrophagelike morphologies and were observed along the LPS injection tract and scattered throughout the hilus of the dorsal hippocampus and cerebral cortices. This LPS-mediated response was found to be specific in that the LPS-hyporesponsive mouse strain (C3H/HeJ) failed to demonstrate significant brain or plasma levels of TNF-alpha after LPS administration compared to C3H/HeN mice. CONCLUSION: These results suggest that the age-related increases in TNF-alpha production and mortality following the intracerebroventricular administration of LPS may be due to an increased endotoxin hypersensitivity of brain microglia/macrophages within aged animals.

Aging↗
PubMedDate not supplied

Acoustic and perceptual indicators of normal and pathological voice.

The aim of this study was to obtain acoustic correlates to vocal quality of a group of men and women with and without voice disorders, based on evaluations of a group of judges experienced in the field of vocal rehabilitation. In male subjects, perceptual evaluation of normal, hoarse and rough voice qualities was related to the following acoustic features: frequency perturbation measures (JITA, RAP, and SPPQ), amplitude perturbation (SAPQ and VAM), soft phonation index (SPI) and fundamental frequency tremor intensity (FTRI). While these measures presented normal values for normal voice, hoarseness showed some deviations in perturbation frequency variables and very high SPI values, while rough voice showed deviations in all the measures. Qualities of female voices were perceived as normal, breathy and hoarse, but the acoustic correlates of these qualities were less conclusive.

Adult↗
PubMedDate not supplied

[Molecular genetics of astrocytomas].

Astrocytomas are the most frequent group of intracranial tumors. Among them, glioblastoma is the most aggressive one. In this review we will describe the most common genetic abnormalities found out in astrocytomas. We will refer to the epidermal growth factor receptor (EGFR), p53, p16, PTEN and DMBT1 genes. We will also present certain genetic aspects that influence the progression to glioblastoma.

English Abstract↗