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J Guzman

Publications and source records attributed to J Guzman.

At least 37 records · Page 2Linked to original sources
PubMed1998

Different expression of integrins by mononuclear phagocytes in peripheral blood and bronchoalveolar lavage fluid.

Alveolar macrophages (AM) originate from blood monocytes and, during the maturation process, undergo functional and morphological changes which are also reflected in their phenotypic pattern. Among the macrophage membrane antigens, adhesion molecules of the integrin family are particularly important for effector functions and cell-cell interactions. The aim of this study was to analyse the membrane expression of selected integrins by AM recovered from bronchoalveolar lavage (BAL) as compared to their precursors, peripheral blood monocytes (PBM). The cells were stained using a sensitive immunoperoxidase assay with 10 different monoclonal antibodies. The data showed a higher expression by AM than PBM of all but one of the studied adhesion molecules. The only exception was CD11b (Mac-1, CR3) which showed a higher expression in PBM than in AM. Several molecules, for example, CD49d (VLA-4), CD51 (vitronectin receptor), and CD54 (intercellular adhesion molecule-1, ICAM-1) were found to be upregulated by AM in patients with a lymphocytic pattern of BAL. In contrast, the phenotype of PBM does not show any changes in these patients. In conclusion, we have demonstrated differences in the expression of integrins between AM and PBM which can be partially responsible for some of their functional differences.

Adult↗
PubMed1997

Smoker's lung transplanted to a nonsmoker. Long-term detection of smoker's macrophages.

Alveolar macrophages (AM) from smokers contain characteristic smoker's inclusion bodies within the cytoplasm as a result of ingestion of substances in the inhaled smoke. How long these smoking-related changes in the AM population can be seen after smoking cessation is largely unknown. We had the unique opportunity to investigate a 51-yr-old never-smoker after single lung transplantation (TX) for alpha 1-antitrypsin deficiency emphysema who received a donor's lung from a heavy cigarette smoker. Serial bronchoalveolar lavage (BAL) was performed in the donor's lung for transplant surveillance at defined time intervals, and the percentage of AM with characteristic smoker's inclusions was counted on slides stained with May-Grünwald-Giemsa stain. The patient had an uneventful course after TX with no major infectious complications or episodes of rejection. One month after TX the percentage of smoker's AM was 98%. BAL after 2, 5, 7, and 12 mo showed a similar high percentage. After 18 mo a first a decrease was seen, down to 78%, and after 2 yr a decrease to 59% was seen. After 3 yr, the smoker's AM had mostly disappeared, only 3% were still present. In conclusion, smoker's inclusions in AM may be detected for at least 2 yr after smoking has ceased, which is considerably longer than the estimated life span of the AM.

Bronchoalveolar Lavage Fluid↗
PubMed1997

Human immunoglobulin preparations suppress the occurrence of Epstein-Barr virus-associated lymphoproliferation.

Suppression of Epstein-Barr virus (EBV) lymphoproliferation by three commercial human immunoglobulin (hu-Ig) preparations, one enriched with immunoglobulin A (hu-IgA-IgG) and the other two containing more than 97% immunoglobulin G (hu-IgG) with anti-EBV antibodies was studied. All three human preparations suppress EBV-induced lymphoproliferation in vitro and reduce release of interleukin (IL)-6 and IL-10 dose-dependently, irrespective, however, of the titer of EBV-specific antibodies present. This result was unexpected. Human Ig also reduces human recombinant IL-6-induced lymphoproliferation in EBV-free cultures and augments low-dose human recombinant IL-10-provoked suppression. In vivo studies used mice with severe combined immunodeficiency (SCID), reconstituted with human tonsillar mononuclear cells, and then infected with EBV from B95-8-derived supernatants. Immediate injection of hu-Ig after EBV infection, if given only once, delayed, and if given every two or four weeks, abolished the induction of EBV-associated lymphomas. Delay of hu-Ig injection by 48 hours after infection was less effective. Hu-IgG was consistently more efficacious than hu-IgA-IgG. Under these conditions the best survival rates were obtained with sustained hu-IgG administrations every two weeks. Serum hu-IL-6 and hu-IL-10 were detectable only in lymphoma-bearing SCID mice. Hu-Ig treatment reduced the detectability of both cytokines. These results suggest that hu-Ig-with antibodies to EBV-may exert a beneficial treatment potential for EBV-induced lymphoproliferation in immunocompromised patients. The dependence of this suppressive effect of hu-Ig on specific anti-EBV antibodies in vivo remains to be resolved.

Animals↗
PubMed1996

Staurosporine inhibits the proliferation, alters the cell cycle distribution and induces apoptosis in HT-29 human colon adenocarcinoma cells.

Staurosporine (ST), a potent inhibitor of protein kinase C (PKC), was evaluated for its effect on the proliferation of HT-29 colon adenocarcinoma cells; PKC is associated with increased colon cell proliferation. ST inhibited cell proliferation in a time- and concentration-dependent manner by up to 90%. It also blocked the G2/M phase of the cell cycle and induced classical apoptosis (sub-diploid peak on flow cytometry, DNA ladder, and typical morphological changes). The kinetics of these changes suggest that low ST concentrations (2-20 nM) may act via a different mechanism from higher (100-1000 nM) ones. The role of ST, which is currently evaluated as an antitumor agent, in colon cancer requires further evaluation.

Adenocarcinoma↗
PubMed1995

In vitro immunization: generation of neutralizing monoclonal antibodies to human interleukin-10.

The potential of the in vitro immunization technique to evoke an immune response against an immunomodulatory protein was evaluated using, as antigen, human interleukin-10 (IL-10), a novel cytokine with pleiotropic effects on human and murine lymphocytes and macrophages. After pre-priming the support cells for 48 h and subsequent 3-day stimulation of splenocytes from a non-immune BALB/c mouse with recombinant human IL-10 (rhIL-10; 2 micrograms/ml), significant stimulation of splenocytes was observed. 7 days after fusion with the non-secreting myeloma line X63/Ag8.653, IL-10-specific antibodies were detected by ELISA and dot blot in more than 70% of the hybridoma supernatants. After limiting dilution of the hybridoma cells showing IL-10-neutralizing activity in a bioassay using murine MC/9 mast cells, the isotype of the monoclonal antibodies (mAbs) obtained was 20% IgM, 16% IgG and 6% IgA. All other antibodies elicited IgM as well as IgG isotypes. The neutralizing activity of the specific mAbs tested was dose-dependent. Our results show that in vitro immunization can be employed successfully to generate functional mAbs to immunomodulatory proteins, even if these exhibit cross-species activity.

Animals↗
PubMed1995

Alveolar macrophage TNF-alpha release and BAL cell phenotypes in sarcoidosis.

The aim of this study was to investigate the relationship between release of tumor necrosis factor-alpha (TNF-alpha) by alveolar macrophages (AM) and the phenotypic characteristics of bronchoalveolar lavage (BAL) cells in sarcoidosis. We studied the spontaneous release of TNF-alpha by AM in vitro and the phenotypic characteristics of freshly recovered BAL T-cells and AM in 31 individuals (13 with active sarcoidosis, nine with inactive sarcoidosis, and nine normal controls). TNF-alpha was measured by enzyme-linked immunosorbent assay (ELISA) in supernatants from unstimulated AM after 24 h culture. Phenotypic markers of BAL cells were determined by an immunocytochemical assay. AM of patients with active sarcoidosis released more TNF-alpha (1,355 +/- 133 pg/ml/ 10(6) AM/24 h) than those of the inactive group (651 +/- 142 pg/ml/10(6) AM/24 h) or the normal controls (425 +/- 121 pg/ml/10(6) AM/24 h), with p < 0.001 for both comparisons. The amount of TNF-alpha released correlated positively with the percentage expression of CD4 (r = 0.72) and CD25 (r = 0.70) by lymphocytes, and of CD14 (r = 0.63), VLA-4 (r = 0.59), FRD1 (r = 0.67) and 27E10 (r = 0.67) by AM, with p < 0.001 for all correlations. In conclusion, this relationship suggests that these antigens may be considered as cellular activation markers, and that some of these AM antigens may indirectly characterize the AM phenotype that is capable of producing TNF-alpha.

Adult↗
PubMed1995

Depressive symptomatology in single women heads of households in Puerto Rico: a comparative analysis.

The present study examines depressive symptomatology among women in Puerto Rico, using data from an island wide population-based sample. We focus on single women heads of households (SWHH) defined as divorced, separated, widowed and never married women with no permanent mate who have the main economic responsibility for their households. The study aims to identify social factors such as family responsibilities, stressful life events, and reduced levels of social support, that may contribute to the risk for depressive symptoms in these women. This is a growing population: the 1990 Census reported that 23% of all households in Puerto Rico were headed by women, an increase from 14% in 1970. The present study was based on a probability sample of adults (17-68 years), interviewed using a structured schedule, from which we analyzed the female subjects. Women were classified in three mutually exclusive groups: single women heads of households (SWHH, n = 138), single women not heads of households (SWNHH, n = 104), and married women not heads of households (MW, n = 275). Our finding that single women heads of households were especially vulnerable to depressive symptomatology is consistent with that of other studies in the United States. Also consistent with previous research, SWHH were found to be older, poorer, have less education and more often lived in urban areas, as compared to other women. Having children at home was associated with more depressive symptoms among both groups of single women, but not among married women. And the availability of emotional supporters had a weaker effect for SWHH. Furthermore, quality of support was found to be more important for these women than number of persons available for emotional support. The study has several implications for family policy and mental health prevention. Since SWHH are vulnerable for depressive symptomatology and their number is increasing, programs should be developed to attend the special needs of these women. These programs could include the provision of child care and the creation of self-help groups to build on their strengths and to combat isolation and loneliness.

Adolescent↗
PubMed1994

Diagnostic value of anti-neutrophil cytoplasmic and anti-endothelial cell antibodies in early Kawasaki disease.

OBJECTIVE: To assess the diagnostic potential of anti-neutrophil cytoplasmic antibodies (ANCA) and anti-endothelial cell antibodies (AECA) to distinguish early Kawasaki disease (KD) from febrile diseases resembling KD. DESIGN: Case-control study. SETTING: Tertiary care facility. PATIENTS: Eighteen patients with KD tested within 2 weeks of disease onset and before immune globulin therapy; 20 control children with fever and at least one other KD criterion; 21 children with noninflammatory disorders (patients scheduled for elective surgery, or after trauma). METHODS: We detected ANCA by immunofluorescence and enzyme-linked immunosorbent assay (ELISA), and AECA by a cell-ELISA with fixed human umbilical vein endothelial cells. RESULTS: We found that 7 of 18 patients with KD and 6 of 20 febrile control patients had ANCA (by immunofluorescence or ELISA, p value not significant); 3 of 18 patients with KD and 8 of 20 febrile control patients had AECA (p value not significant). One of three patients with KD who had aneurysms had ANCA; none had AECA. CONCLUSIONS: The ANCA and AECA tests used in this study did not differentiate early KD from other childhood diseases with which it may be confused.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1994

ICAM-1 and integrin expression on isolated human alveolar type II pneumocytes.

Adhesion molecules are involved in the recruitment of leucocytes to sites of inflammation. In this study, we determined the expression of several adhesion molecules on isolated human alveolar type II pneumonocytes. Type II pneumocytes were isolated from 10 normal lung specimens, by enzymatic digestion with dispase, followed by metrizamide gradient centrifugation and panning on immunoglobulin G (IgG)-coated plastic dishes. With the freshly isolated type II cells, immunostaining was performed using a sensitive immunoperoxidase slide technique. In all cases, 60-90% of type II cells were positive for intercellular adhesion molecule-1 (ICAM-1) (CD54). A minor portion of type II cells expressed the alpha 4 (CD49d) subunit of the beta 1-integrins, and the alpha-v (CD51) subunit of the vitronectin receptor. CD11a, CD11b, CD11c, CD18, CD49b, and CD49f failed to demonstrate any immunostaining with type II cells. In conclusion, the observation of the expression of ICAM-1 and, to a lesser degree, of some integrin subunits, may indicate that alveolar type II cells participate in local immune and inflammatory responses.

Antigens, CD↗
PubMed1994

Molecular genetics of the glutamine synthetases in Rhizobium species.

Soil bacteria of the genus Rhizobium and Bradyrhizobium establish symbiotic interactions with leguminous plants that result in the formation of specialized structures, the nodules, in which the bacteria differentiate into bacteroids and fix nitrogen. Rhizobial glutamine synthetase (GS) activity is very low in the nodule. The ammonia produced by the bacteroids is exported to the plant cell, where it is assimilated by the GS from the plant, whereas in the free-living state, Rhizobium and Bradyrhizobium species assimilate ammonia for growth. Another characteristic of these species is that they possess two glutamine synthetase isozymes, known as GSI and GSII. A third glutamine synthetase isozyme, called GSIII, has been found in R. meliloti and R. etli.

Amino Acid Sequence↗
PubMed1993

In vitro immunization with antigen directly blotted from SDS-polyacrylamide gels to polyvinylidene difluoride membranes.

A new immunization method has been developed for the production of monoclonal antibodies. This technique uses small amounts of partially purified and weak immunogenic antigen, bound to membranes after blotting from SDS-PAGE. For this purpose two different membranes have been tested. Immobilon-P polyvinylidene difluoride (PVDF) membranes were less mitogenic than nitrocellulose membranes, and were therefore selected for the in vitro immunization using 6-pyruvoyl tetrahydropterin synthase as antigen. The in vitro immunization method was then used for the production of monoclonal antibodies against 6-pyruvoyl tetrahydropterin synthase, one of the key enzymes on the biosynthetic pathway of tetrahydrobiopterin, the natural cofactor of the mammalian aromatic amino acid hydroxylases. The antibodies obtained were mainly of the IgM type.

Alcohol Oxidoreductases↗
PubMed1992

Production of monoclonal antibodies against human 6-pyruvoyl tetrahydropterin synthase and immunocytochemical localization of the enzyme.

Monoclonal antibodies were produced against human pituitary gland 6-pyruvoyl tetrahydropterin synthase, one of the key enzymes in the biosynthesis of tetrahydrobiopterin, by in vitro immunization with the antigen directly blotted from SDS-PAGE to polyvinylidene difluoride membranes. The antibodies produced show crossreactivity in the enzyme linked immunosorbent assay, not only with the human 6-pyruvoyl tetrahydropterin synthase but some also with the same enzyme isolated from salmon liver. 6-Pyruvoyl tetrahydropterin synthase was localized immuno-enzymatically in peripheral blood smears and in skin fibroblasts by the use of these monoclonal antibodies and the alkaline phosphatase monoclonal anti-alkaline phosphatase labeling technique.

Alcohol Oxidoreductases↗
PubMed1992

Purification and characterization of 6-pyruvoyl tetrahydropterin synthase from human pituitary gland.

6-Pyruvoyl tetrahydropterin synthase, the enzyme that catalyses the conversion of 7,8-dihydroneopterin triphosphate to 6-pyruvoyl tetrahydropterin, was purified 3,330-fold from human pituitary gland with an overall recovery of 30%. The native enzyme has a molecular mass of 68 kD and consists of four identical subunits of 16.5 kD. The pH optimum of the enzyme in Tris/HCl buffer is 7.5. The enzyme is dependent on Mg2+ and NADPH and has a Michaelis-Menten constant of 10 microM for its natural substrate, 7,8-dihydroneopterin triphosphate. The isoelectric point of the human enzyme is 4.3-4.6. The human pituitary gland enzyme is heat instable in contrast to the enzymes from human, rat and salmon liver, and Drosophila head. The amino acid composition showed remarkably high content of acidic amino acids Asp and Glu. The N-terminus was found to be blocked.

Alcohol Oxidoreductases↗
PubMed1992

BOOP in Europe.

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Adult↗