Search PubMed⌕ Search

Biomedical subjects

J Merino

Publications and source records attributed to J Merino.

At least 73 records · Page 4Linked to original sources
PubMed1997

Brucellar prosthetic arthritis in a total knee replacement.

The infecting pathogens most commonly implicated in prosthetic joint infections are staphylococci, streptococci, and gram-negative rods. Prosthetic infections caused by Brucella spp. are rarely described in the literature. Treatment of prosthetic infections remains complex and controversial, the most accepted course being antibiotic treatment with removal or retention of prosthetic components. The case of a 60-year-old man who developed Brucella septic arthritis of the right knee in a total knee replacement is reported. Conservative treatment using a three-drug therapy was employed, with excellent results.

Arthritis, Infectious↗
PubMed1997

Treatment with anti-LFA-1 alpha monoclonal antibody selectively interferes with the maturation of CD4- 8+ thymocytes.

Maturation of T lymphocytes in the thymus is driven by signals provided by soluble factors and by the direct interaction between thymocytes and stromal cells. Although the interaction between T-cell receptor (TCR) and major histocompalibility complex (MHC) molecules on stromal cells is crucial for T-cell development, other accessory molecules seem to play a role in this process. In order to better understand the role of lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) molecules in thymocyte maturation, mice were treated from birth with saturating doses of non-cytolytic-specific monoclonal antibodies. The effect of this treatment on thymocyte subpopulations and the expression of CD3 and TCR-alpha beta by these cells was investigated by flow cytometry. Our data demonstrated that the effective saturation of LFA-1 alpha chain in the thymus, but not ICAM-I or LFA-I beta chain, selectively interfered with the maturation of CD8+ T cells, as manifested by a marked reduction in the frequency of CD4-8+ thymocytes expressing high levels of CD3 and TCR-alpha beta. This selective reduction was also observed in peripheral blood mononuclear cells and spleen cells. The analysis of the frequencies of various V beta TCR showed that CD4-8+ thymocytes were globally affected by the treatment. These results underline the importance of the interaction between LFA-1 and its ligands in the maturation of CD8+ T cells and document the existence of different molecular requirements for the differentiation of CD4+ and CD8+ T cells.

Animals↗
PubMed1997

Serum soluble selectins in patients undergoing cardiopulmonary bypass. Relationship with circulating blood cells and inflammation-related cytokines.

BACKGROUND: Membrane-bound selectins mediate the adhesion among leukocytes, platelets and endothelial cells, while circulating (soluble) selectins may function as competitive inhibitors of them. Open heart surgery is known to induce activation of these cells. METHODS: We studied the acute responses of soluble selectins, circulating blood cells and inflammation-related cytokines in 12 patients undergoing elective open heart surgery with cardiopulmonary bypass. Serial blood samples were withdrawn before, during and after surgery. RESULTS: Serum soluble E-selectin concentrations did not change significantly during all the perioperative period. In contrast, P-selectin decreased after the initiation of cardiopulmonary bypass and remained low until the end of surgery. L-selectin showed a similar course. A decrease in platelet count and albumin was found during the perioperative period and an increase in leukocyte count was found after cardiopulmonary bypass. Clear elevations in circulating IL (Interleukin)-6, IL-8, and IL-10 were found after the end of surgery, while IL-12 levels remained undetectable. CONCLUSIONS: While serum inflammatory cytokines clearly rise in response to open heart surgery, soluble selectins do not change (E) or decrease (P and L). Correcting for haemodilution, E-selectin rises postoperatively, but the decrease in P- and L-selectins is not explained by haemodilution.

Adult↗
PubMed1996

Constitutive expression of bcl-2 in B cells causes a lethal form of lupuslike autoimmune disease after induction of neonatal tolerance to H-2b alloantigens.

The bcl-2 protooncogene has been shown to provide a survival signal to self-reactive B cells, but it fails to override their developmental arrest after encounter with antigen. Furthermore, constitutive expression of bcl-2 in B cells does not promote the development of autoimmune disease in most strains of mice, indicating that signals other than those conferred by bcl-2 are required for long-term survival and differentiation of self-reactive B cells in vivo. To further examine the factors that are required for the pathogenesis of autoimmune disease, we have assessed the effect of bcl-2 overexpression on the development of host-versus-graft disease, a self-limited model of systemic autoimmune disease. In this model, injection of spleen cells from (C57BL/6 x BALB/c)F1 hybrid mice into BALB/c newborn parental mice induces immunological tolerance to donor tissues and activation of autoreactive F1 donor B cells through interactions provided by allogeneic host CD4+ T cells. BALB/c newborns injected with spleen cells from (C57BL/6 x BALB/c)F1 mice expressing a bcl-2 transgene in B cells developed high levels of anti-single-stranded DNA and a wide range of pathogenic autoantibodies that were not or barely detectable in mice injected with nontransgenic spleen cells. In mice injected with transgenic B cells, the levels of pathogenic autoantibodies remained high during the course of the study and were associated with long-term persistence of donor B cells, development of a severe autoimmune disease, and accelerated mortality. These results demonstrate that bcl-2 can provide survival signals for the maintenance and differentiation of autoreactive B cells, and suggest that both increased B cell survival and T cell help play critical roles in the development of certain forms of systemic autoimmune disease.

Aging↗
PubMed1996

Completely allogeneic spleen cells induced cytolytic neonatal tolerance to alloantigens, but failed to establish allo-helper interactions with host T cells.

The injection of spleen cells from F1 mice into-newborns from a parental strain results in the establishment of cytolytic tolerance to donor alloantigens and the development of a lupus-like disease. This syndrome is the consequence of the recognition by alloreactive host CD4+ T cells of discordant major histocompatibility complex (MHC) class II antigens on semi-allogeneic donor B cells. We have analysed whether completely allogeneic spleen cells are as able as semi-allogeneic spleen cells to induce cytolytic tolerance to donor alloantigens and to co-operate with alloreactive T cells for autoantibody production. BALB/c mice were injected at birth with Thy-1-depleted spleen cells from (C57BL/6 x BALB/c)F1 or C57BL/6 mice, either alone or in combination. Cytolytic tolerance was always induced, as manifested by persistence of chimerism and acceptance of skin allografts. However, only F1 semi-allogeneic B cells were activated by alloreactive host T cells to produce anti-DNA IgG antibody. The deficient co-operation between BALB/c CD4+ T cells and completely allogeneic C57BL/6 B cells was confirmed after neonatal injection of (C57BL/ 6 x BALB/c)F1(Igha) spleen cells together with C57BL/6(Ighb) spleen cells. These mice developed anti-DNA antibodies bearing only the Igha allotype. Similar results were observed in experiments of allogeneic interaction in vitro, in which BALB/c CD4+ T cells were cocultured with either (C57BL/6 x BALB/c)F1 or C57BL/6 B cells. The present results demonstrate that completely allogeneic spleen cells efficiently induced cytolytic unresponsiveness to donor alloantigens, but B cells contained in this spleen cell population were unable to establish allo-helper interactions with alloreactive CD4+ T cells, suggesting that cytolytic and helper T-cell interactions involved in alloreactivity may be different.

Animals↗
PubMed1996

Effect of hypercholesterolaemia on platelet growth factors.

Evidence from several sources suggests that important interactions occur between platelets and low-density lipoproteins. This study was undertaken to find out if diet-induced hypercholesterolaemia affects the growth factor content in circulating platelets. Minipigs were fed either normal diet supplemented with 2% cholesterol (n = 12) or normal diet alone (n = 12). After 4 months, mean platelet volume was significantly lower (P < 0.05) and monocyte count was significantly higher (P < 0.05) in the cholesterol group. Serum and intraplatelet levels of platelet-derived growth factor (BB homodimer) and transforming growth factor beta 1 were statistically unchanged after diet. Hypercholesterolaemia did not affect the proliferative effect of either serum or platelet lysates on porcine vascular smooth muscle cells and Swiss-3T3 cells in culture. A significant positive correlation between Swiss-3T3 and smooth muscle cell proliferation was present in both groups. These results suggest that the atherosclerosis-promoting effect of hypercholesterolaemia cannot be explained by its direct effect on smooth muscle cell proliferation or by changes in serum or intraplatelet concentrations of growth factors.

3T3 Cells↗
PubMed1996

[Cardiac angiosarcoma].

We report a case of a 29-year-old patient with recurrent hemorrhagic pericardial effusion secondary to a right atrial mass detected by transthoracic echocardiography. A more detailed anatomic study was provided by transesophageal echocardiogram and nuclear magnetic resonance imaging. During surgery, a biopsy confirmed the diagnosis of angiosarcoma. We discuss the contribution of echocardiography and other noninvasive methods to evaluate intracardiac tumors. A brief review of treatment and prognosis is made.

Adult↗
PubMed1996

[Bacteremia caused by Capnocytophaga sp: presentation of 2 cases, one with endocarditis. Review of the literature].

Capnocytophaga sp. is a gram-negative bacilli, scarcely documented as the cause of bacteremias. Two cases of bacteremia caused by Capnocytophaga sp, one of them with endocarditis, are reported here. A review of previous published cases is also presented. One of the patients was immunocompromised, because of chemotherapy, the other, suffered from a rheumatic-cardiopathy which was complicated with endocarditis. Both patients developed an alteration of the oral mucosa. Antibiotic therapy proved to be effective with two patients.

Adult↗
PubMed1996

Value of plasma P-selectin for vascular complications in liver transplantation.

Recent data suggest that plasma P-selectin, an adhesion molecule, may be a clinically useful marker for thrombosis. Hepatic vessel thrombosis is one of the most serious complications following liver transplantation. To assess the contribution of the soluble P-selectin to this complication, we measured plasma P-selectin levels in 32 orthotopic liver transplantations, pre-, intra-, and post-operatively. We found that levels of circulating P-selectin were not different between cirrhotic patients and healthy subjects. Of the 32 patients, 8 had vascular complications. We found a significant increase in the plasma P-selectin concentration in the thrombotic group in early postoperative period compared with the non-thrombotic group (p < 0.002). It measurement may facilitate the diagnosis of thrombosis in the early postoperative period after liver transplantation, and therefore the management of these patients.

Adult↗
PubMed1996

A1 demonstrates restricted tissue distribution during embryonic development and functions to protect against cell death.

Members of the bcl-2 gene family are essential regulators of cell survival in a wide range of biological processes. A1, a member of the family, is known to be expressed in certain adult tissues. However, the precise tissue distribution and function of A1 remains poorly understood. We show here that A1 is expressed in multiple tissues during murine embryonic development. In the embryo, A1 was detected first at embryonic day 11.5 in liver, brain, and limbs. At day 13.5 of gestation, A1 expression was observed in the central nervous system, liver, perichondrium, and digital zones of developing limbs in a pattern different from that of bcl-X. In the central nervous system of 15.5-day embryos, A1 was expressed at high levels in the ventricular zone and cortical plate of brain cortex. Significantly, the interdigital zones of limbs and the intermediate region of the developing brain cortex, two sites associated with extensive cell death, were devoid of A1 and bcl-X. The expression of A1 was retained in many adult tissues. To assess the ability of A1 to modulate cell death, stable transfectants expressing different amounts of A1 protein were generated in K562 cells. Expression of A1 was associated with retardation of apoptotic cell death induced by actinomycin D and cycloheximide as well as by okadaic acid. Confocal microscopy showed that the A1 protein was localized to the cytoplasm in a pattern similar to that of Bcl-2. These results demonstrate that the expression of A1 is wider than previously reported in adult tissues. Furthermore, its distribution in multiple tissues of the embryo suggests that A1 plays a role in the regulation of physiological cell death during embryonic development.

Animals↗
PubMed1996

[Diagnostic efficiency of biological markers of alcohol consumption for the detection of excessive drinkers].

The objective of our study was to test the usefulness of some biological markers of alcoholism to detect heavy drinkers, using a structured interview with a 7-day memory as this is currently considered the most reliable technique for determining alcohol consumption. A transversal, observational study was designed with a sample representative of the working population of the province of Alicante seen by the Ibermutua medical service. Participants were selected randomly and classified according to region and sex. The total sample include 1,033 subjects (644 men and 389 women, mean age 36 +/- 11.7 years). Of these 13.5 were heavy drinkers (> 40 g. of alcohol per day), 23.3 moderates drinkers (20-40 g. alcohol per day). Average consumption of alcohol was from 26 g/day + 29.9 grams. In order to quantify the random error, the confidence interval was set at 95. The methods used to test the biological markers were 2 x 2 tables and the calculation of indicators of sensitivity (S). specificity (E), positive predictive value (Vp+), negative predictive value (Vp-) and effectiveness. The highest S was obtained by associating various markers (65.5%), followed by GGT with 53.9%. The GGT/ALP quotient obtained an E of 95.9% and an AST of 92.2%. The GGT/ALP quotient achieved the best effectiveness (85%) and Vp+ (36.2%) and the association of markers the best Vp-at 92.9%, followed by GGT at 91.3%. In spite of the fact that the markers studied do not meet the conditions required to be considered acceptable as screening (S and E > 80%), their use seems appropriate if their limitations are kept in mind (many false negatives). As the GGT/ALP quotient has the highest E, there are few false positives. In order to decrease the number of false negatives, an evaluation of GGT or marker association can be done for those with negative values. In order to resolve the disadvantages of Vp+, the best solution is to order tests for groups of markers that are most prevalent in heavy drinkers.

Adult↗
PubMed1996

[Growth factors and mitogenic activity in experimental hypercholesterolemia].

INTRODUCTION: Hypercholesterolemia is associated with increased platelet reactivity and changes in megakaryopoiesis, which might influence the synthesis of growth factors in the megakaryocyte. MATERIAL AND METHODS: 20 miniature pigs were randomly assigned to received 18 weeks of either regular pig chow feed (control group, n = 10) or a high cholesterol diet (cholesterol group, n = 10). Platelet count, mean platelet volume, platelet distribution width and bleeding time were determined in both groups. Intraplatelet and serum mitogenic activity was quantified by Swiss 3T3 and vascular smooth muscle cells proliferation assays. Insulin-like growth factor I and platelet-derived growth factor (BB isoform) levels were quantified in platelet lysates and in serum in both groups. RESULTS: Hypercholesterolemia was associated to a significant decrease in mean platelet volume and bleeding time, but it did not affect the proliferative effect of serum and platelet lysates nor its growth factor content. CONCLUSIONS: Taken together, our results suggest that although hypercholesterolemia affects platelet reactivity, its atherosclerosis-promoting effects cannot be explained by a direct effect on vascular smooth muscle cell proliferation or by changes in serum or intraplatelet growth factor content.

3T3 Cells↗
PubMed1996

[Quality of drug prescriptions by the Spanish internal medicine services].

Many registered drugs in different countries not always have been tested by clinical assays and their efficacy has no definitively proved. Good clinical practice must assume the prescription of the more efficacy drugs. The aim of this study is to evaluate the quality of the drugs prescribed by spanish general internists. We analyze the treatments prescribed by general internists using their hospital medical records. The records were offered by the Heads of the Internal Medecine Departments of Spanish hospitals with 250 beds or more when required by the Spanish Society of Internal Medecine. A random sample, stratified by the hospital size, was obtained from the whole of the Spanish hospitals. Quality of the drugs was determined using two criteria: A. Their intrinsic value; it was decided it was high if clinical assays showed their efficacy and security, and low of it was not B. The number of different chemical substances in the drug; we considered a high quality criteria if only one chemical substance, or two with proved synergistic efficacy were present, and low if it was more than two, or without proved synergistic efficacy. The sample was 250 clinical records, with 1022 different prescriptions; the records were collected between February and July 1994. We found that 94.06 +/- 1.45 of evaluated treatments have a high intrinsic value, and 96.93 +/- 1.06 have only one chemical component. The drugs without a high intrinsic value were: oral hypoglycaemics, some including several combinations of vit B, drugs acting on the cerebral blood flow and some mucolitics. Spanish general Internists usually prescribed monocomponent drugs with proved efficacy and safety.

Drug Prescriptions↗
PubMed1995

[Importance of HDL cholesterol determination in the evaluation of coronary risk in clinical practice].

OBJECTIVE: To validate to what extent the isolated determination of total Cholesterol (TC) is effective when seeking to predict coronary risk. DESIGN: An observational crossover study of the analytic determinations of the clinics which systematically request TC and HDL-Cholesterol (HDL)--case-finding method. SETTING: Health Centre. PARTICIPANTS: 631 analytic determinations, with samples from people who attended a Health Centre between May and November 1992, were studied. MEASUREMENTS AND MAIN RESULTS: As proof of certainty the Atherogenic Index (AI) was used for the relative risks (RR) of suffering a coronary event in line with the Framingham study. The confidence limits (CL) were calculated to 95% in order to quantify random error and permit comparison. On varying the cut-off points of TC the indicators changed, being more sensitive (S) and less specific (E) with the lower figures: 180 mg/dl, RR > 1, S = 97.5% (CL: 100-94.7) and E = 30.5% (36.8-24.2); RR > 2, S = 100%, E = 22.1% (26.9-17.3) and RR > 3, S = 100%, E = 20.8% (25.3-16.3). As values of TC increase, S diminishes and E increases: 250 mg/dl, RR > 1, S = 48.3% (57.2-39.4), E = 87.2% (91.8-82.6); RR > 2, S = 58.6% (76.5-40.7), E = 77.2% (82-72.4) and RR > 3, S = 63.6% (92-35.2), E = 75.3% (80.1-70.5). CONCLUSIONS: HDL must be determined if TC is -200 mg/dl. If everyone with RR > 2 is to be detected, HDL-cholesterol from TC > or = 180 mg/dl must be measured.

Adult↗
PubMed1995

The ability of B cells to participate in allogeneic cognate T-B cell interactions in vitro depends on the presence of CD4+ T cells during their development.

We have assessed in vitro whether the absence of T cells in the natural environment of F1 hybrid mice influences the ability of their B cells to participate in an allogeneic interaction with CD4+ cells from parental mice. For this purpose, B cells from athymic CB6F1 nu/nu mice or from CB6F1 mice depleted in different T cell subsets were incubated in vitro with purified CD4+ BALB/c cells. Here, we show that B cells from CB6F1 nu/nu mice or from euthymic CB6F1 mice depleted from birth of CD4+ cells were unable to respond to allogeneic stimulation with BALB/c CD4+ T cells, which produce normal levels of cytokines. The addition of dendritic cells from euthymic CB6F1 mice did not revert this defect. B cells from CB6F1 mice lacking CD4+ T cells showed a selective reduction in the expression of CD23. We found a complete restoration of both the CD23 expression and the ability of CB6F1 nu/nu B cells to respond in vitro to an allogeneic stimulation by CD4+ cells in two instances: (1) after neonatal engraftment of a syngeneic thymus into CB6F1 nu/nu mice, which partially reconstitutes the mature T cell populations; and (2) after preincubation of B cells from CB6F1 nu/nu mice with high concentrations of rIL-4. However, the addition of an anti-CD23 mAb did not interfere with the polyclonal activation of CB6F1 B cells in this system. These results indicate that CD4+ cells play an important role in the functional maturation of B cells by promoting their ability to participate in allogeneic cognate T-B cell interactions.

Animals↗