PubMed Health⌕ Search

Biomedical subjects

L R Lopez

Publications and source records attributed to L R Lopez.

At least 19 recordsLinked to original sources
PubMed2006

Antibodies against beta2-glycoprotein I complexed with an oxidised lipoprotein relate to intima thickening of carotid arteries in primary antiphospholipid syndrome.

To explore whether antibodies against beta2-glycoprotein I (beta2GPI) complexed to 7-ketocholesteryl-9-carboxynonanoate (oxLig-1) and to oxidised low-density lipoproteins (oxLDL) relate to paraoxonase activity (PONa) and/or intima media thickness (IMT) of carotid arteries in primary antiphospholipid syndrome (PAPS). As many as 29 thrombotic patients with PAPS, 10 subjects with idiopathic antiphospholipid antibodies (aPL) without thrombosis, 17 thrombotic patients with inherited thrombophilia and 23 healthy controls were investigated. The following were measured in all participants: beta2GPI-oxLDL complexes, IgG anti-beta2GPI-oxLig-1, IgG anti-beta2GPI-oxLDL antibodies (ELISA), PONa, (para-nitrophenol method), IMT of common carotid (CC) artery, carotid bifurcation (B), internal carotid (IC) by high resolution sonography. Beta2GPI-oxLDL complex was highest in the control group (p < 0.01), whereas, IgG anti-beta2GPI-oxLig1 and IgG anti-beta2GPI-oxLDL were highest in PAPS (p < 0.0001). In healthy controls, beta2GPI-oxLDL complexes positively correlated to IMT of the IC (p = 0.007) and negatively to PONa after correction for age (p < 0.03). PONa inversely correlated with age (p = 0.008). In PAPS, IgG anti-beta2GPI-oxLig-1 independently predicted PONa (p = 0.02) and IMT of B (p = 0.003), CC, (p = 0.03) and of IC (p = 0.04). In PAPS, PONa inversely correlated to the IMT of B, CC and IC (p = 0.01, 0.02 and 0.003, respectively). IgG anti-beta2GPI-oxLig-1 may be involved in PAPS related atherogenesis via decreased PON activity.

Adult↗
PubMed2006

Oxidized low-density lipoprotein and beta2-glycoprotein I in patients with systemic lupus erythematosus and increased carotid intima-media thickness: implications in autoimmune-mediated atherosclerosis.

Oxidative stress and LDL modification (oxLDL) are early pro-atherogenic events. OxLDL binds beta2GPI producing immunogenic oxLDL/beta2GPI complexes. Antibodies to these complexes have been associated with arterial thrombosis in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). Circulating oxLDL/beta2GPI complexes, IgG and IgM antibodies to these complexes were measured by ELISA in 30 SLE patients asymptomatic for cardiovascular disease (mean age 31 years) and 27 age/sex matched healthy controls. Carotid intima-media thickness (IMT) was measured by ultrasound in all patients and controls. Forty-seven percent of SLE presented plaques (median IMT of 0.65 +/- 0.12 mm) while only 7% of the controls had plaques (median IMT of 0.50 +/- 0.04 mm, P < 0.001). Median optical density (OD450nm) for oxLDL/beta2GPI complexes in SLE was 0.244 +/- 0.07, higher than controls (0.174 +/- 0.09, P < 0.001). Median OD for IgG anti-oxLDL/beta2GPI antibodies was also higher in SLE (0.297 +/- 0.26) compared to controls (0.194 +/- 0.07, P < 0.001) while the median OD for IgM antibodies in SLE (0.444 +/- 0.46) was not different than controls (0.326 +/- 0.22, P = 0.267). There was no correlation between IMT and oxLDL/beta2GPI complexes, IgG or IgM antibodies, possibly reflecting the complex interrelationship between these serologic elements and tissue factors in the arterial wall. These results support the hypothesis that oxLDL/beta2GPI complexes and IgG (not IgM) anti-oxLDL/beta2GPI antibodies contribute to the development of autoimmune-mediated atherosclerosis.

Adolescent↗
PubMed2006

Atherogenic oxidized low-density lipoprotein/beta2-glycoprotein I (oxLDL/beta2GPI) complexes in patients with systemic lupus erythematosus and antiphospholipid syndrome.

Oxidized low-density lipoprotein (oxLDL) interacts in vitro with beta2-glycoprotein I (beta2GPI) via LDL-derived specific ligands forming oxLDL/beta2GPI complexes. Circulating oxLDL/beta2GPI complexes have been demonstrated in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). Autoimmune vascular inflammation and oxidative stress contribute to oxLDL/beta2GPI complex formation. Immunohistochemical staining of atherosclerotic lesions suggest that these complexes are formed in the arterial wall and released into circulation. The demonstration of antibodies to oxLDL/beta2GPI complexes indicates that these complexes are immunogenic, and the coexistence of complexes and antibodies suggest an active pro-thrombotic/pro-atherogenic role in the development of autoimmune vascular complications. Circulating oxLDL/beta2GPI complexes can be measured by ELISA using a monoclonal antibody specific to complexed human beta2GPI to capture beta2GPI bound to oxLDL. An enzyme-conjugated monoclonal antibody to human Apo B 100 allows the specific detection of oxLDL/beta2GPI complexes. OxLDL/beta2GPI complexes were common in SLE and APS patients suggesting an underlying process of inflammation and oxidation. Using oxLDL/beta2GPI complexes as capture antigen, antibodies to oxLDL/beta2GPI can be measured by ELISA. Serum levels of IgG anti-oxLDL/beta2GPI antibodies were significantly higher in SLE patients with APS compared to SLE controls without APS. Further, high titers of these IgG antibodies were observed in APS patients with a history of arterial thrombosis. The presence of circulating oxLDL/beta2GPI complexes and IgG antibodies to these complexes indicates significant vascular injury and oxidative stress as well as an active role in autoimmune-mediated atherothrombosis.

Antibodies, Monoclonal↗
PubMed2005

Oxidized LDL/beta2-glycoprotein I complexes: new aspects in atherosclerosis.

beta2-glycoprotein I (beta2GPI) is a major antigenic target for antiphospholipid antibodies. Oxidized low-density lipoprotein (oxLDL) is the principal lipoprotein found in atherosclerotic lesions, and it colocalizes with beta2GPI and immunoreactive lymphocytes. oxLDL/beta2GPI complexes appeared in the blood circulation of patients with diseases, such as systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), systemic sclerosis, diabetes mellitus and chronic renal diseases. Thus, the complexes may be associated with systemic and chronic inflammation of the vasculature. IgG anti-oxLDL/beta2GPI complexes autoantibodies and their immune complexes were detected only in SLE/APS patients and in its animal model and were strongly associated with arterial thrombosis. The oxLDL/beta2GPI complexes were internalized by macrophages via IgG anti-beta2GPI antibody-mediated phagocytosis. In contrast, IgM anti-oxLDL antibodies derived from hyperlipidemic mice reduced the incidence of atherosclerosis. The distribution patterns of IgG and IgM anti-oxLDL antibodies in patients suggest the different roles of these antibodies.

Anticoagulants↗
PubMed1995

Logical responses to youth who run away from home: implications for psychiatric mental health nursing.

1. Runaway youths do not fit into a typical profile; they are adolescents of every race, ethnic group, and religious orientation; they are representative of every socioeconomic status and geographic location in America. 2. Psychosocial events including physical and sexual abuse are common antecedents to runaway behaviors. 3. Implications for psychiatric mental health nursing practice include working with community programs focused on reducing runaway episodes; implementing preventive measures focused on strengthening parenting and problem-solving skills for reducing conflict with families with adolescent children; and promoting responsible sexuality through adequate and responsible sex education and counseling.

Adolescent↗
PubMed1992

Clinical significance of immunoglobulin A versus immunoglobulins G and M anti-cardiolipin antibodies in patients with systemic lupus erythematosus. Correlation with thrombosis, thrombocytopenia, and recurrent abortion.

Serum levels of immunoglobulins (Ig) A, G, and M anti-cardiolipin (aCL) antibodies were determined by enzyme-linked immunosorbent assay in a group of selected systemic lupus erythematosus female patients. Patients were divided into three groups based on their clinical history of thrombosis with or without thrombocytopenia (group I), thrombocytopenia alone (group II), and neither of these (group III). After the aCL antibody levels were determined, the patients' obstetric histories of pregnancies and abortions were reviewed. A high incidence of one or more abortions was seen only in group I patients. A high prevalence of elevated levels of IgA and IgG (but not IgM) aCL antibodies was observed in group I patients. However, among the patients in group II, only the levels of IgA aCL antibodies were increased. In both groups, the addition of the IgA aCL determination--to the classical IgG and IgM aCL assays--increased the prevalence of positive reactors in 31.6%. These results indicate that high levels of IgA aCL antibodies correlated better with thrombocytopenia than either IgG or IgM. Also, the importance of including the determination of IgA aCL antibodies to assess properly the risk of thrombosis, thrombocytopenia, and recurrent abortions in systemic lupus erythematosus patients is demonstrated.

Abortion, Habitual↗
PubMed1992

Reduction of intra-oral demineralization of enamel after single exposures to sodium fluoride.

Studies demonstrated the effects of single rinses with low concentrations of NaF on the intra-oral demineralization of enamel. Blocks of bovine enamel were covered with Streptococcus mutans IB1600, mounted in palatal appliances, and worn in the mouths of volunteers for specified times. Subjects rinsed with solutions of NaF, with or without sucrose. Demineralization was determined as changes in iodide penetrability (delta Ip) of the enamel, while the pH and F of the streptococcal plaque, and enamel F, were determined with ion-specific electrodes. Delta Ip was reduced by about 80% (from 14.5 +/- 2.7 to 2.8 +/- 2.3 units) when 250 micrograms F/mL was added to the sucrose rinse. Corresponding plaque pH's were 4.1 +/- 0.5 and 4.2 +/- 0.3, consistent with a lack of effect on bacterial acidogenesis. Protection against mineral loss was concentration-dependent. Administration of sucrose at different times after NaF revealed that the effect of F persisted for at least 60 min. Analyses of plaque F demonstrated an initial elevation and concentration within the cells, followed by a drop to stable, baseline values. Enamel F increased slowly to almost 500 micrograms/g enamel after 105 min. The protective effect of F appeared to be manifested in two stages, the first related to a high plaque F and the second to F that became incorporated into the enamel. Analysis of the data suggested that F was transferred from plaque to enamel during the experimental period.

Adult↗
PubMed1991

Adolescents' attitudes toward mental illness and perceived sources of their attitudes: an examination of pilot data.

This exploratory descriptive pilot study examined the attitudes of 89 Floridian adolescents toward mental illness and found significant differences according to gender and education about mental illness. Responses to social distance items showed that adolescents tended to be less accepting as they were proposed relationships that suggested greater intimacy with the mentally ill. The mass media, personal experience with someone who had a mental illness, and parents were perceived by the adolescents as the most important sources of their attitudes. The major implications for nursing practice with adolescents, and particularly in the school system, are discussed with suggested interventions.

Adolescent↗
PubMed1991

Lack of correlation between food retention on the human dentition and consumer perception of food stickiness.

When dental health professionals advise that sticky foods be avoided, it is left to the consumer to choose correctly among different foods. In this study, comparisons were made among consumer ratings of stickiness of 21 commercially available foods and objective measurements of tooth retention of each of the foods. No correlation was found between the two, and neither the rates of clearance of food particles from the teeth nor the rates of clearance of food-derived sugars from the saliva correlated with ratings of food stickiness. Cookies, crackers, and potato chips were most retentive, whereas caramels, jelly beans, raisins, and milk chocolate bars were among those poorly retained. Clearance rates appeared to vary inversely with initial retention. However, chocolate-caramel bars exhibited high initial retention and a very rapid rate of clearance from the teeth. The findings show that consumers cannot accurately assess the retentiveness of foods and, thus, the advise simply to avoid sticky ones is inadequate.

Adhesiveness↗
PubMed1989

Prevention of sucrose-induced demineralization of tooth enamel by chewing sorbitol gum.

Measurements were made of the effect of chewing sorbitol gum on the intra-oral demineralization induced by rinsing with 10% sucrose solutions. Blocks of bovine enamel were covered with a layer of Streptococcus mutans IB1600, and mounted on palatal appliances that were worn by five subjects for defined periods of time. Enamel demineralization was determined by following changes in iodide penetrability (delta Ip) of the enamel surfaces. Delta Ip increased to a maximum of about 15 units between 30 and 45 min, while the pH of the S. mutans plaque dropped to below 4 by 15 min. Plaque pH returned to 4.9 by 60 min. Chewing sorbitol gum after the sucrose rinse minimized further increases in delta Ip and brought about a more rapid return of the S. mutans plaque pH toward neutrality. The effect of chewing gum was greater when chewing was initiated earlier so that, when gum was given at five min after the sucrose rinse, demineralization was only 37% of that obtained without gum. The findings confirm earlier reports on the effect of gum on plaque pH, and directly demonstrate the profound protective effects that chewing sorbitol gum can have on tooth enamel.

Adult↗
PubMed1988

Immediate skin test reactivity to common aeroallergens in patients with respiratory allergies: a comparative analysis of allergen-induced skin reactions and their histamine controls.

The results of the immediate skin test response to a panel of 16 common aeroallergens performed in a group of 659 consecutive patients with symptoms suggestive of a respiratory allergy were analyzed. A group of 108 healthy individuals served as control subjects. Ninety-four percent of the patients and 87% of the control subjects had at least one allergen-induced reaction (wheal greater than or equal to 2 by 2 mm). The prevalence of positive skin reactions to each aeroallergen was equally high in both groups. However, if a skin reaction is considered as positive only when an allergen-induced wheal is equal or larger compared to the 50% of the wheal obtained with the histamine control in that individual, 70% of the patients had positive skin reactions and only 38% of the control subjects were positive (p less than 0.05). Similarly, the prevalence rates to five aeroallergens (pollen, Fusarium, Mucor, Pullularia, and Curvularia) in the patient group were reduced to those levels observed with the control group, suggesting they are clinically less important. The age and not the sex influenced both the prevalence rates (p less than 0.001) and the mean size (p less than 0.01) of allergen and histamine-induced skin reactions. Lower prevalence rates and mean size values were observed in the youngest group (0 to 9 years). Moreover, there was an inverse relationship between lower skin reactivity with more younger subjects in our patient population. These results indicate that patients and healthy individuals have similar mechanisms for skin reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Lymphocytotoxic antibodies and intermediate immune complexes in hypergammaglobulinemic purpura of Waldenström.

Immune complexes, lymphopenia, and lymphocytotoxic antibodies were detected in two patients with hypergammaglobulinemic purpura of Waldenström. These abnormalities were further characterized in one patient. Ultracentrifugation analysis of this patient's serum showed an intermediate peak likely representing medium sized immune complexes. Circulating IgG-containing immune complexes (2-ME resistant Clq binding material) and IgM rheumatoid factor (2-ME sensitive) were also detected. A sequential study of cold reactive IgM lymphocytotoxic antibodies revealed a significant inverse correlation between antibody levels and peripheral lymphocyte counts. The possible implications of these findings in the pathogenesis of hypergammaglobulinemic purpura are discussed.

Antigen-Antibody Complex↗
PubMed1987

Cryoglobulinemia and cutaneous vasculitis in human brucellosis.

We report the occurrence of cryoglobulinemia and cutaneous vasculitis in three patients with brucellosis caused by Brucella melitensis. The isolated cryoglobulins were characterized as mixed polyclonal or type III. Brucella agglutinin activity was not detected in any of the cryoglobulins analyzed. However, the same agglutinin titer and the presence of precipitin lines of identity in immunodiffusion gels were observed in the supernatant of the cryoglobulins and the serum. Rheumatoid-factor activity was present in all the cryoprecipitates tested. Resolution of the purpuric lesions with therapy coincided with a decrease in serum cryoglobulins and, in one patient, with normalization of his serum C3 levels. These findings suggest that the immunological abnormalities manifested by our patients were the direct consequence of the brucellosis infection and provide additional evidence to support the role for immunological mechanisms in the pathogenesis of human brucellosis.

Adolescent↗
PubMed1984

The hypocomplementemic urticarial-vasculitis syndrome: therapeutic response to hydroxychloroquine.

We report a patient with hypocomplementemic urticarial-vasculitis syndrome. This case illustrates the continuum between urticaria and purpura characteristic of hypocomplementemic urticarial-vasculitis syndrome. Clq precipitin was demonstrated in the patient's serum and in the diethylaminoethylcellulose-ion exchange fraction containing only IgG. A skin biopsy specimen of urticarial and purpuric lesions demonstrated leukocytoclastic vasculitis and granular deposition of C3 and Clq in the basement membrane with IgA, IgM, C3, and Clq in postcapillary venules. Serial total hemolytic complement activity and Clq determinations were performed, and the response to several treatment regimens is presented. Symptomatic and serologic improvement was observed only with hydroxychloroquine.

Adult↗
PubMed1977

The requirement of viable thymocytes for species-specific attachment to and release from macrophages.

The role of the thymocyte in its species-specific binding to macrophages has been explored. Although formalin treatment of macrophages resulted in loss of binding to thymocytes, formalin treatment of thymocytes did not have this effect. However, two differences between living and formalin-treated thymocytes were noted. Formalin-treated thymocytes bound to macrophages of any species whereas the binding of living thymocytes was species specific. Living thymocytes attained maximum binding in approximately 1 hr and then the fraction bound gradually diminished. Formalin-treated thymocytes remained bound to the macrophage and appeared to be phagocytized. Released thymocytes did not bind to fresh macrophages, but released macrophages bound to fresh thymocytes. The results suggest that the binding of thymocytes to macrophages results in maturation of thymocytes.

Animals↗