Biomedical subjects

M Rosa

Publications and source records attributed to M Rosa.

At least 19 recordsLinked to original sources

PubMed1992

Simultaneous determination of cotinine and trans-3'-hydroxycotinine in human serum by high-performance liquid chromatography.

A high-performance liquid chromatographic method with ultraviolet photometric detection has been developed for the quantitation of cotinine and trans-3'-hydroxycotinine in human serum. A solid-phase extraction procedure was performed for the analytes and the internal standard, N-ethylnorcotinine, before chromatography. The use of a 30-cm reversed-phase column and a mobile phase of water-methanol-0.1 M sodium acetate-acetonitrile (67:24.5:6.5:2, v/v), pH 4.3, prevented the co-elution of caffeine with cotinine. The limit of quantitation observed with this method was 5 ng/ml for both cotinine and trans-3'-hydroxycotinine. The present method proved useful for the determination of serum levels of these metabolites, correlating with nicotine daily intake.

Chromatography, High Pressure Liquid↗

PubMed1992

How the steady-state cotinine concentration in cigarette smokers is directly related to nicotine intake.

The relationship between nicotine intake and steady-state cotinine concentration was studied in a sample of 125 subjects who smoked their usual brands of cigarettes. Nicotine and tar yield of cigarettes was determined with a smoking machine, under standardized conditions. Blood was drawn about 8 hours after the last cigarette was smoked and serum cotinine was measured by high performance liquid chromatography. Cotinine levels ranged from 11 to 400 ng/ml, and nicotine daily intake ranged from 1 to 33 mg/day. Regression analysis and the correlation coefficient, r = 0.919, significant at p less than 0.0001, showed that steady-state cotinine level was linearly and directly related to daily available nicotine, with an increase in correlation coefficient directly related to the increase in tar and nicotine yield. From the findings we also conclude that smokers of low-tar cigarettes do not tend to compensate for lower yields of nicotine.

Adolescent↗

PubMed1991

L-carnitine uptake in differentiating human cultured muscle.

We studied carnitine uptake in human skeletal muscle growing in culture for up to 30 days, and correlated it to the degree of muscle differentiation revealed by myotube formation and muscle-specific creatine-kinase isozyme accumulation. In our study carnitine uptake was a saturable specific process with two distinct components: a high affinity uptake at carnitine concentration between 0.5 and 10 microM and a low affinity uptake at carnitine concentration between 25 and 200 microM. High affinity uptake (Km 4.17-5.50 microM, Vmax 11.78-19.6 pmol/h per mg protein) did not change during muscle maturation in culture. Low affinity uptake showed significant changes in Km and Vmax in the various stages of muscle differentiation. Our studies suggest the existence of a muscle-specific system, operating at physiological carnitine concentration, which gradually develops during muscle maturation in culture. We hypothesize that a defect of the low affinity muscle-specific uptake might be the cause of the primary muscle carnitine deficiency syndrome.

Adult↗

PubMed1991

Expression and functional characterization of a soluble form of vascular cell adhesion molecule 1.

Vascular cell adhesion molecule 1 (VCAM1) is a leukocyte adhesion molecule induced on human endothelium in vitro and in vivo by inflammatory stimuli. A truncated cDNA for VCAM1 was constructed, stably expressed in Chinese Hamster Ovary (CHO) cells, and the secreted recombinant soluble form of VCAM1 (rsVCAM1) purified to homogeneity by immunoaffinity chromatography. Immobilized rsVCAM1 is a functional adhesion protein, and selectively binds only VLA4-expressing cells, including human B and T lymphocytes, NK cells, and certain lymphoblastoid cell lines. T cell subset analyses indicate preferential binding of CD8+ memory cells. rsVCAM1 should prove valuable for the further study of the role of VCAM1 during inflammatory and immune responses in vivo.

Amino Acid Sequence↗

PubMed1991

Elimination of caffeine interference in high-performance liquid chromatographic determination of cotinine in human plasma.

A high-performance liquid chromatographic method with ultraviolet photometric detection for the determination of cotinine in human plasma was described. The use of a 30-cm reversed-phase column and of a mobile phase consisting of water-methanol-0.1 M sodium acetate-acetonitrile (72:21:5.6:1.4, v/v), pH 4.1, eliminated caffeine interference. A simplified solid-phase extraction procedure was also performed for plasma samples.

Caffeine↗

PubMed1991

Endothelial-leukocyte adhesion molecule 1 stimulates the adhesive activity of leukocyte integrin CR3 (CD11b/CD18, Mac-1, alpha m beta 2) on human neutrophils.

Two classes of adhesion molecules have well-defined roles in the attachment of unstimulated polymorphonuclear leukocytes (PMN) to cytokine-treated endothelial cells. Endothelial-leukocyte adhesion molecule 1 (ELAM-1) on endothelial cells interacts with specific carbohydrate residues on the PMN, and the leukocyte integrins (CD18 antigens) on PMN interact with intracellular adhesion molecule 1 and other structures on endothelium. Here we show that these two classes of molecules can act sequentially in an "adhesion cascade". Interaction of PMN with ELAM-1-bearing endothelial cells causes PMN to express enhanced adhesive activity of the integrin CR3 (CD11b/CD18). Expression of ELAM-1 on the cytokine-treated endothelium appears both necessary and sufficient for the stimulation of CR3 activity since blockade of ELAM-1 with mAbs prevents the activation of CR3 by cytokine-treated endothelium, and immobilized recombinant ELAM-1 activates CR3. The ability to activate CR3 is shared by chemattractants, suggesting that ELAM-1 may serve as a "tethered chemattractant." This hypothesis is strengthened by the observation that recombinant soluble ELAM-1 directs movement of PMN in chemotaxis chambers. These results suggest a mechanism by which multiple adhesive molecules may function together in diapedesis. ELAM-1 serves both as an adhesin and as a trigger that recruits the participation of additional adhesion molecules. Our results also suggest that ligands for adhesion molecules may also be "receptors" capable of generating intracellular signals.

Antibodies, Monoclonal↗

PubMed1991

Human monocytes bind to two cytokine-induced adhesive ligands on cultured human endothelial cells: endothelial-leukocyte adhesion molecule-1 and vascular cell adhesion molecule-1.

Vascular cell adhesion molecule-1 (VCAM-1) and endothelial-leukocyte adhesion molecule-1 (ELAM-1) are adhesive proteins induced on endothelium by cytokines. We examined the contribution of these adhesive proteins to human peripheral blood monocyte adherence to endothelium using transfected Chinese hamster ovary (CHO) cells stably expressing these proteins and monoclonal antibodies (MoAbs) to ELAM-1, VCAM-1, or CD49d/CD29 (VLA-4), the leukocyte receptor for VCAM-1. Monocytes bound to CHO cells transfected with cDNA of ELAM-1 or VCAM-1. Binding to ELAM-1 was inhibited by MoAb to ELAM-1 and binding to VCAM-1 was inhibited by MoAb to VCAM-1 or the alpha-chain of very late activation antigen-4 (VLA-4) (CD49d). Additive inhibition of adherence to unstimulated human umbilical vein endothelium (HUVE) was observed when monocytes were pretreated with both MoAb to CD49d and MoAb to CD18, the common beta-chain of the leukocyte beta 2 integrin receptors. Adherence of monocytes to HUVE stimulated by recombinant human tumor necrosis factor-alpha was not reduced by MoAbs to CD18, CD49d, or ELAM-1 when used singly, but combinations of these MoAbs produced significant inhibition. We conclude that multiple receptor-ligand systems are involved in monocyte adherence to endothelium.

Animals↗

PubMed1991

CD4-Pseudomonas exotoxin hybrid proteins: modulation of potency and therapeutic window through structural design and characterization of cell internalization.

Replacing the Pseudomonas exotoxin A (PE) cell binding domain with the human immunodeficiency virus (HIV) gp120 binding domain from CD4 yields a hybrid toxin (CD4-PE) with potential therapeutic use in treating acquired immunodeficiency syndrome (AIDS). To find the most therapeutically potent combination of CD4 and PE four different hybrid toxins composed of one [CD4(122)] or two [CD4(181)] Ig-like CD4 domains and sequences of PE where the binding domain was partially [PE(392)] or completely [PE(364)] removed were constructed and expressed in Escherichia coli. The number of CD4 domains determined the binding affinity to gp120 and in cell viability assays the window between specific and nonspecific cytotoxicity. The length of PE determined the potency of the drug. The optimal hybrid toxin was composed of two Ig-like domains of CD4 and PE(392). Investigation of the internalization mechanism of CD4-PE revealed that the hybrid toxin binds to target cells and is endocytosed within one hour. However, more than 6 hours are required for maximum translation inhibition. In contrast to PE which is inhibited by ammonium chloride treatment, cell toxicity of CD4-PE is not affected by ammonium chloride. Further investigations showed that the acid-induced hydrophobicity change which is required for membrane translocation is also observed with CD4-PE but at significantly higher pH than with PE.

ADP Ribose Transferases↗

PubMed1991

Effect of ritanserin, specific 5HT-2 antagonist, on PRL secretion in normal subjects and in different hyperprolactinaemic conditions.

The availability of a new specific anti 5HT-2 compound, ritanserin (RTS), led us to further investigate the role of serotonin in controlling PRL secretion. The drug was administered to normoprolactinaemic subjects and to patients with differing hyperprolactinaemic conditions. While RTS failed to modify PRL levels in normoprolactinaemic subjects and in patients with PRL-secreting pituitary adenomas, a marked decrease in the hormone was obtained in patients with functional and puerperal hyperprolactinaemia. The lack of effect of RTS in PRL-secreting pituitary adenomas suggests that the reported suppression of PRL by other antiserotoninergic drugs, such as metergoline, is probably due to their concomitant dopaminergic activity.

Adenoma↗

PubMed1991

Insulin resistance in myotonic dystrophy.

The aim of the present study was to obtain a comprehensive picture of the rate of insulin secretion and of tissue sensitivity to the endogenous hormone in myotonic dystrophy patients (MyD). The minimal model approach was utilized for the analysis of frequently sampled intravenous glucose tolerance test data (FSIGT). This method provided the characteristic parameters: SI, insulin sensitivity index; SG fractional glucose disappearance independent of dynamic insulin; n, fractional insulin clearance; phi 1 and phi 2 first and second phase insulin delivery sensitivities to glucose stimulation. In MyD patients SI was reduced (p less than 0.01) by 71% to 1.4 +/- 0.3 x 10(-4) min-1/(microU/ml), whereas in controls it was 4.85 +/- 0.77; SG was within the normal range: 0.044 +/- 0.012 min-1 in MyD patients and 0.036 +/- 0.017 min-1 in controls; phi 1 increased in MyD patients (7.4 +/- 1.3 min (microU/ml)/(mg/dl) versus 4.1 +/- 1.2 in controls); phi 2 increased in MyD patients (126 +/- 47 x 10(4) min-2/(microU/ml)/(mg/dl) versus 17 +/- 6 in controls; p less than 0.05). MyD patients showed a normal tolerance with the glucose disappearance constant, KG within the normal range: 2.75 versus 2.62% min-1 in controls. In MyD patients insulin resistance was associated with a higher than normal insulin delivery for both secretory phases, although the second phase was responsible for releasing a greater amount of hormone. In conclusion MyD patients try to compensate for overall insulin resistance by a more marked pancreatic response.

Adult↗

PubMed1991

Muscle carnitine deficiency in patients with severe peripheral vascular disease.

BACKGROUND: This study was designed to evaluate the effect of severe peripheral arterial insufficiency on carnitine concentrations and carnitine acetyltransferase and palmitoyltransferase activities in the ischemic skeletal muscles of patients with severe peripheral vascular disease. METHODS AND RESULTS: Nine biopsy specimens of ischemic muscles were obtained from five patients undergoing reconstructive vascular surgery. Biopsies from 35 normal subjects served as controls. Ischemic muscles showed a significant reduction in total carnitine from the control value of 20.9 +/- 5.2 to 11.6 +/- 6.2 nmol/mg noncollagen protein (p less than 0.01). A significantly lower free carnitine and acylcarnitine content contributed to this reduction. Similarly, carnitine acetyltransferase activity was reduced in the ischemic muscles from the control value of 102.1 +/- 41.2 to 52.9 +/- 22.1 nmol/min/mg noncollagen protein (p less than 0.01). On the contrary, carnitine palmitoyltransferase activity did not show any change (0.29 +/- 0.05 nmol/min/mg noncollagen protein in the ischemic muscles and 0.28 +/- 0.07 nmol/min/mg noncollagen protein in controls). Carnitine, acylcarnitines, and enzyme activities were also measured in the ischemic muscles in four additional patients 2 days after intravenous administration of L-propionylcarnitine (1.5 g as a single bolus followed by an infusion of 1 mg/kg/min for 30 minutes). Treatment restored normal levels of carnitine and its esters in the ischemic muscles but did not affect enzyme activities. CONCLUSIONS: Demonstration of carnitine deficiency in severe peripheral vascular disease substantiates previous findings showing the efficacy of carnitine supplementation to ischemic muscles. Furthermore, the feasibility of restoring carnitine homeostasis with L-propionylcarnitine provides the basis for clinical trials aimed at assessing the efficacy of this carnitine ester in the treatment of peripheral vascular disease.

Aged↗

PubMed1991

[Evaluation of the Vitek system in the identification and biotyping of Streptococcus agalactiae].

Using the Vitek card for identification of gram-positive agents, 244 strains of Streptococcus agalactiae were studied. Twenty five out of these strains were studied during 3 consecutive days. The study also involved 25 pairs of maternal and neonatal strains. The system gave correct identification of only 52 out of 244 strains of S. agalactiae. Due to the low reproducibility of the system it is suggested that the bionumbers used in the codification of a microorganism should be avoided.

Bacterial Typing Techniques↗

PubMed1990

Vascular cell adhesion molecule-1 mediates lymphocyte adherence to cytokine-activated cultured human endothelial cells.

The expression and function of a new cytokine-induced endothelial cell adhesion protein, vascular cell adhesion molecule-1 (VCAM-1), was characterized in vitro by using a monoclonal antibody, MoAb 4B9, which recognizes a functional epitope on this protein. As determined by enzyme-linked immunosorbent assay and radioimmunoprecipitation of metabolically labeled cells, VCAM-1 was minimally expressed on unstimulated human umbilical vein endothelium (HUVE), but was rapidly induced by recombinant human tumor necrosis factor-alpha (rhTNF-alpha), rh interleukin-1, and lipopolysaccharide. In contrast to intercellular adhesion molecule-1, VCAM-1 was not induced on dermal fibroblasts or arterial smooth muscle cells after stimulation with rhTNF, or on keratinocytes after stimulation with rh interferon-gamma. MoAb 4B9 significantly inhibited the adherence of peripheral blood lymphocytes (PBL) and lymphocytic cell lines, but not neutrophils, to rhTNF-activated HUVE. The inhibitory effect of MoAb 4B9 on PBL adherence to HUVE was additive to that produced by the CD18 MoAb 60.3. These results show that VCAM-1 mediates a CD18-independent pathway of peripheral blood lymphocyte adherence to cytokine-stimulated HUVE. We propose that lymphocyte binding to VCAM-1, induced on endothelium by cytokines, may be an important component of lymphocyte emigration at sites of inflammation or immune reaction.

Animals↗

PubMed1990

A blocking monoclonal antibody to endothelial-leukocyte adhesion molecule-1 (ELAM1).

ELAM1 is a leukocyte adhesion molecule induced on human umbilical vein endothelial cells (HUVECs) by inflammatory cytokines. Balb/C mice were immunized with COS cells transiently expressing cell-surface ELAM1 after transfection with ELAM1 cDNA. After fusion, ELAM1-specific monoclonal antibodies (Mabs) were identified by selective adhesion to ELAM1-expressing, but not control, CHO cells, and to cytokine-treated but not untreated HUVECs. One Mab, designated BB11, binds to and immunoprecipitates ELAM1 expressed on HUVECs, COS and CHO cells. BB11 blocks the interaction of ELAM1 with human PMN, the human myelomonocytic cell line HL60, and the human colon carcinoma line HT29.

Antibodies, Monoclonal↗

PubMed1990

Aneurysmal bone cyst. Long-term follow-up of 20 cases.

Twenty cases of aneurysmal bone cyst were reviewed, with an average follow-up of 10.3 years. Twelve patients still had open growth plates at diagnosis, but all of them were fully grown at follow-up. The treatments performed were: resection of the cyst or of the whole affected bone, curettage, and curettage and bone grafting. Radiation therapy was a complementary treatment in three cases. Two patients relapsed, one that had been treated by curettage alone and one by curettage and bone grafting. Five patients showed skeletal deformities at follow-up. Two had lesions of the growth plate, most likely caused by radiation therapy, whereas in the other three growth had probably been impaired by surgical trauma.

Adolescent↗

PubMed1990

[Rhythm profile in patients with psoriatic arthritis].

OBJECTIVE: To analyze the rhythmic profile in patients with psoriatic arthritis (PA). DESIGN: In order to evaluate the rhythmic profile of patients with PA, we have carried out ambulatory 24 hour ECG recordings in 22 patients presented consecutively to the Holter ECG laboratory. SETTING: Patients followed in a specialised rheumatology consultation, in Santa Maria Hospital. PATIENTS: We have studied 22 patients (pts), 10 male and 12 female, aged 49.8 +/- 8.4 years, presenting PA diagnosed in average 12.9 years before. A group of 36 individuals, 25 male and 11 female, aged 37 +/- 8 years and without disease, were used as control. RESULTS: All patients were in sinus rhythm with a mean heart rate of 71 +/- 6 (min - 51.5 +/- 7.0 and max - 130.3 +/- 15.0). In 8 (36.6%) there were sinus bradycardia less than 50/min and sinus tachycardia (greater than 120/min) in 15 patients (68.1%). Two patients (9%) presented supraventricular tachycardia and one had AV block. There were premature atrial systoles in 14 pts (63.6%), and ventricular arrhythmias in 9 (40.9%). In control group, there were sinus bradycardia in 16.6%, sinus tachycardia in 33.3%, premature atrial systoles in 33.3% and ventricular arrhythmias in 25% of them; in 11% there were conduction disturbances. CONCLUSIONS: a) Premature atrial systoles were the rhythm disturbance more prevalent. b) Patients with PA presented a significant higher incidence of sinus bradycardia and sinus tachycardia. c) Cardiac conduction disturbances were not frequent. d) Our results may suggest the presence of a subtle autonomic dysfunction in patients with psoriatic arthritis.

Adult↗

PubMed1989

[Neuro-AIDS: a multicenter neuroradiological study].

The results are described of a retrospective multicentric CT/MR study of 141 neuro-AIDS patients (IV group CDC classification); 114 patients were drug addicted, 13 homosexual, 8 polytransfused, and 6 had other risk factors. The mean age was 29.6 years. The pathologic agent was identified in 47 cases by c.s. fluid examination, biopsy, autopsy or specific treatment response: it was HIV in 20 cases, toxoplasmosis in 11, cryptococcosis in 9, leishmaniasis, salmonella and papovavirus in single cases. In the follow up of 2 cases, a Kaposi's sarcoma and a primitive CNS lymphoma occurred. The main clinical features were AIDS-dementia complex (45% of cases) and focal neurologic manifestations (36%). The neuroradiological protocol consisted of 238 CT exams (97 controls), most of them with DDD (delayed double dose) technique, 7 MR exams (0.15 T) and 2 angiographies. CT findings were divided into 3 groups: negative (16%), atrophic (47%) and focal lesions (37%). In the first and second group, HIV and cryptococcal infections were the main pathologic agents. In the third group toxoplasma infections were discovered, and TB granulomas and other pathologic conditions, with ring-like or nodular enhancement, in cortical/cortico-medullary location. In follow-up patients a high tendency of evolution towards focal lesions was observed, even in negative cases. The DDD enhancement technique allowed in most cases both the demonstration of very small lesions and their grading. According to the literature CT, though a highly sensitive method, is inferior to MR imaging; however our experience in this field is currently insufficient. The specific diagnosis of pathologic agents of neuro-AIDS is difficult, due to the high number of opportunistic AIDS-related infections and neoplasms, with overlapping features: differential diagnostic criteria can be assessed only by comparing the clinical, microbiological, topographic, CT and MR findings. CT and MR exams are necessary to guide and monitor therapy and to plan stereotaxis biopsy.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Radiotherapy and L-triiodothyronine in the treatment of high-grade astrocytoma.

From January 1983 to March 1984, eight patients with high-grade astrocytoma received postoperative irradiation concomitantly with triiodothyronine at the Radiation Therapy Department of the I. González Martínez Oncologic Hospital in San Juan, Puerto Rico. There were no complications related to treatment. One patient is alive without evidence of disease at 39 months and seven patients died with disease, one of whom lived for 3 yr. The survival curve for these patients is similar to the survival curve of 18 patients treated at the University of Chicago by surgery, radiation, and triiodothyronine. The value of triiodothyronine as an adjuvant in the treatment of high grade astrocytoma should be further investigated.

Adult↗