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M Ramos

Publications and source records attributed to M Ramos.

At least 73 records · Page 4Linked to original sources
PubMed1999

Ral and Rho-dependent activation of phospholipase D in v-Raf-transformed cells.

Phospholipase D (PLD) activity is commonly elevated in response to mitogenic signals. We reported previously that although the transformed phenotype induced by v-Src was dependent upon Raf-1, the PLD activity induced by v-Src was independent of Raf-1. This observation suggested to us that Raf would not likely be an activator of PLD. However, upon examination of PLD activity in v-Raf-transformed cells, surprisingly, we found that PLD activity is elevated to levels that were even higher than that observed in v-Src-transformed cells. To characterize the mechanism of v-Raf-induced PLD activity, we examined the dependence of v-Raf-induced PLD activity upon protein kinase C (PKC) the small GTPases Ral and Rho, which have all been implicated in the activation of PLD. The v-Raf-induced PLD activity was inhibited by dominant negative mutants for both Ral and Rho. The dependence upon Ral was particularly surprising since Ral is a downstream target of Ras, which is an upstream activator of Raf. Depleting cells of PKC by long term phorbol ester treatment actually increased PLD activity in v-Raf-transformed cells, indicating that v-Raf-induced PLD activity is not dependent on PKC. These data describe a novel mechanism for PLD activation by v-Raf that is independent of PKC, but dependent upon both Ral and Rho GTPases.

3T3 Cells↗
PubMed1999

The South Amerindian allotype HLA-B*3909 has the largest known similarity in peptide specificity and common natural ligands with HLA-B27.

HLA-B*3909 has only been found among South Amerindians, and presumably arose locally in these populations. It differs from B*3901 by a single Tyr to Ser change at position 99. To analyze the influence of this polymorphism on peptide specificity, pool sequence analysis and sequencing of multiple individual ligands from B*3901 and B*3909 were carried out. Both allotypes bind peptides with Arg2 or His2 and nonpolar C-terminal residues. However, whereas His2 is the predominant B*3901 motif, a majority of the B*3909-bound peptides have Arg2. In addition, B*3909 binds peptides with Pro2, and also shows an increased preference for Pro3. In spite of their differences, both subtypes bind overlapping peptide repertoires, as indicated by the identification of several identical ligands from their respective peptide pools. B*3909 is significantly more similar in its peptide specificity to HLA-B27 than B*3901. This is due to the increased preference of B*3909 for Arg2 and to low suitability of HLA-B27 for His2. The similarity between HLA-B27 and B*3909 was confirmed by identification of a natural ligand common to both allotypes. In addition, multiple HLA-B27 ligands bound efficiently B*3909 in vitro. The results indicate that, among the HLA class I allotypes of known peptide specificity, B*3909 is the most similar in its peptide binding properties to HLA-B27, which is absent in South Amerindians. This may have implications for the susceptibility of individuals in these populations to spondyloarthropathies.

Amino Acid Sequence↗
PubMed1999

Determination of dexamethasone in feed by TLC and HPLC.

Two detection methods are described for the determination of dexamethasone in feed, which may be used as screening and confirmatory methods. The procedures were developed after studying different extraction and clean-up procedures: feed extraction was optimized using methylene chloride and hexane followed by a tandem solid-phase clean-up step with silica and C18 cartridges. The confirmatory method presented is based on normal-phase high-performance liquid chromatography on a Diol 5 microns column, with hexane-propan-2-ol (90:10 v/v) as mobile phase, followed by diode array detection and confirmation. All parameters are discussed, especially the extraction and clean-up steps. Recovery studies after application of the proposed method to different kinds of feed samples spiked with dexamethasone at levels between 120 and 1600 ng g-1 yielded a mean value of 55.4% with an overall standard deviation of 15.6%. The proposed procedure allows the determination of dexamethasone in feed at levels lower than 50 ng g-1.

Animal Feed↗
PubMed1999

The usefulness of Tc-99m tetrofosmin scintigraphy in the diagnosis and localization of hyperfunctioning parathyroid glands.

PURPOSE: The aim of the work was to study the diagnostic value of Tc-99m tetrofosmin to localize anomalous parathyroid glands in patients with hyperparathyroid disease. METHODS: We studied 31 patients, 19 with primary and 12 with secondary hyperparathyroid disease. Five of these patients were renal graft recipients. All patients underwent surgery. Each patient was injected with 555 to 740 MBq (15 to 20 mCi) Tc-99m tetrofosmin. Subsequently, radionuclide images were acquired 15 and 120 minutes after injection using a low-energy, all-purpose, parallel-hole collimator. Pertechnetate thyroid scintigraphy was obtained in nine cases (24 to 48 h later) when the thyroid activity made it difficult to identify the parathyroid glands. RESULTS: All cases showed tracer uptake as early as 15 minutes after injection. In the group of patients with primary hyperparathyroid disease, 15 showed focal uptake in a parathyroid gland, and surgery revealed an adenoma in the same location. In one patient with hyperplasia, scintigraphy identified only two of four diseased glands. In the three remaining cases, scintigraphy showed focal uptake in the lower parathyroid gland, whereas at surgery the abnormal gland was located in the upper pole. In the secondary hyperparathyroidism group, seven patients showed diffuse tracer uptake in two or more glands, and histologic analysis confirmed hyperplasia in all of them. Five cases showed focal uptake, with three evaluated after surgery (uptake in the only remaining gland); one of them was a renal graft recipient, and the remaining patient had chronic renal failure and was receiving hemodialysis. CONCLUSIONS: Our results suggest that Tc-99m tetrofosmin may be a suitable tracer for preoperative detection and screening of anomalous parathyroid glands. The earlier images at 15 minutes were better than those at 120 minutes. Tc-99m tetrofosmin is cleared more slowly from the normal thyroid than is Tc-99m sestamibi, and both of these tracers may give better results than the old pertechnetate TI-201 subtraction technique.

Adenoma↗
PubMed1999

[Evaluation of two methods to avoid the nephropathy associated with radiologic contrast].

UNLABELLED: Our objective was to establish the efficacy of two methods to avoid contrast associated nephropathy (C.A.N). We studied in prospective and randomized form a sample of 75 patients of whom 25 were assigned to the CONTROL GROUP: without interventions; 25 to the Saline group: 0.45% saline solution I.V., 1.5 cc/kg/min, 6 hours before and after the angiographic study and 25 to the Dopa group: equal procedure plus the aggregate of dopamine 2 micrograms/kg/min, 30 minutes before the study until the termination. The evaluation effected at patient's entry was considered T0, T1, 24 hs after the T2, 48 hs after. In T0 was registered: age, sex, pathological antecedents, drugs and plasmatic creatinine, and in T2 creatinine. An increase of 25% of the plasmatic creatinine in T2 was considered as C.A.N. The latter was present in 13/25 (OR: 1) CONTROL GROUP patients, 7/25 (OR 0.36), Salina group patients and in 5/25 (OR 0.23) Dopa group patients (p = 0.01). No significant difference was registered in the urinary output nor in the plasmatic creatinine levels. It is concluded that hydration during six hours before and after the study with 0.45% saline solution and the same plan with the aggregate of dopamine are effective to prevent a C.A.N.

Acute Kidney Injury↗
PubMed1999

[A quality of life study in women with systemic lupus erythematosus and its relation to disease activity].

OBJECTIVE: To determined in a prospective study the quality of life (QoL) in the systemic lupus erythematosus (SLE) females. We also studied the relationship between QoL and the activity of lupus disease. METHODS: We studied 67 consecutive SLE females. To study the QoL we administered the Medical Outcomes Study Short form Scale SF-36 (MOS-SF36). This questionnaire is composted for 36 question and comprises eighth subscales of QoL. We also measured the activity with the Mexico-SLE Disease Activity Index (MEX-SLEDAI). RESULTS: The mean age of the 67 SLE patients at disease onset was 38.3 +/- 14 years, and mean duration of disease was 66 +/- 42 months. The values of QoL answers were lower. No relationship was found between the age of patients and QoL. The subscales with poor punctuation were the general heath and the role physical. Multiple variate analyses showed that activity was associated with vitality (r = 0.36; p = 0.003). CONCLUSIONS: The MOS-SF36 questionnaire indicate that SLE females patients had lower results about her quality of life.

Adolescent↗
PubMed1999

BSE in Portugal: anticipating the decline of an epidemic.

BACKGROUND: Attention throughout Europe continues to focus on bovine spongiform encephalopathy (BSE), with increasing evidence linking it to the new variant of Creutzfeldt-Jakob disease in humans. In particular, recent attention has been directed at Portugal, where the incidence of confirmed BSE cases continues to rise. METHODS: We modelled the age-specific incidence of BSE in Portuguese-born cattle by birth cohort as a function of: the survival distribution; the cohort-specific incidence of BSE infection; the age-specific probability, conditional on survival, that an infected animal will experience clinical onset; and the under-reporting rate of BSE cases prior to 1998. RESULTS: We obtained good fits to the age-specific incidence of BSE by birth cohort in Portugal. Under a range of assumptions, the estimated incidence of BSE infection was relatively low initially, except possibly in the 1989 cohort, and then rose gradually between the 1992 and 1994 cohorts. The estimated decrease in infection incidence between the 1994 and 1995 cohorts probably reflects the effectiveness of the ban on the use of mammalian meat and bone-meal introduced in Portugal in mid-1994. Assuming no infections in animals born after June 1995, the models predict that the incidence of BSE cases in Portugal will peak in 1999 with BSE case-incidence declining thereafter. DISCUSSION: Our results illustrate the power of epidemiological analysis to detect decreasing trends in infection incidence prior to the resulting decrease in case incidence. The findings should inform the deliberations of the European Commission, which recently reported concerns about the sharp increase in case incidence from 1997 to 1998.

Adolescent↗
PubMed1998

[Comparison of endoscopy, radiology and scintigraphy with Tc-99m-exametazine labeled leukocytes and In-111 labeled human polyclonal immunoglobulin G in the diagnosis of inflammatory bowel disease].

BACKGROUND: The 99mTc-exametazine labelled leukocytes (99mTc-WBC) scintigraphy is an established method for the inflammatory bowel disease (IBD) diagnosis, but the labelled procedure is a large and laborious process. The 111In-labelled human polyclonal immunoglobulin G (111In-IgG) can be an alternative in the non invasive IBD diagnosis. PATIENTS AND METHODS: Thirty-four patients routinely referred for investigation of IBD were studied. The 99mTc-WBC and 111In-IgG were simultaneously injected and images were obtained at 30 min, 3 and 24 h post-injection. The diagnostic was established by histology of endoscopy and/or surgery samples. Images were blindly evaluated by two experienced observers who only knew of the clinical suspicion of IBD. IBD was confirmed in 27 patients (17 with Crohn's disease [CD] and 10 with ulcerative colitis [UC]). RESULTS: Sensitivity, specificity and accuracy were 88.5, 100 and 90.3% respectively for endoscopy, 73.7, 75 and 73.9% for radiology, 59.3, 85.7 and 64.7% for 111In-IgG scan and 96.3, 85.7 and 94.1% for 99mTc-WBC scan. In the diagnosis of CD involvement of small bowel, the 99mTc-WBC scan identified 9/11 patients with confirmed disease, whereas the 111In-IgG scan diagnosed only four of them. In the evaluation of colonic disease, the 99mTc-WBC scan correctly diagnosed 21/22 confirmed patients, being the 111In-IgG scan positive in 13 of them. As far as disease extension concerned, the 99mTc-WBC demonstrated a statistically significance rather number of disease segments than endoscopy, radiology and 111In-IgG scan. CONCLUSIONS: The 99mTc-WBC was an effective method in the diagnosis of suspected IBD patients, both in the evaluation of small bowel disease and colonic disease, with slightly best results for colonic disease, whereas the 111In-IgG scan seems to have no utility neither in diagnosis nor in extension evaluation of IBD.

Adolescent↗
PubMed1998

Functional association between Arf and RalA in active phospholipase D complex.

Activation of phospholipase D1 (PLD1) by Arf has been implicated in vesicle transport and membrane trafficking. PLD1 has also been shown to be associated with the small GTPase RalA, which functions downstream from Ras in a Ras-RalA GTPase cascade that facilitates intracellular signal transduction. Although PLD1 associates directly with RalA, RalA has no effect upon the activity of PLD1. However, PLD1 precipitated from cell lysates with immobilized glutathione S-transferase-RalA fusion protein is active. This suggests the presence of an additional activating factor in the active RalA-PLD1 complexes. Because Arf stimulates PLD1, we looked for the presence of Arf in the active RalA-PLD1 complexes isolated from v-Src- and v-Ras-transformed cell lysates. Low levels of Arf protein were detected in RalA-PLD1 complexes; however, if guanosine 5'-[gamma-thio]triphosphate was added to activate Arf and stimulate translocation to the membrane, high levels of Arf were precipitated by RalA from cell lysates. Interestingly, deletion of 11 amino-terminal amino acids unique to Ral GTPases, which abolished the ability of RalA to precipitate PLD activity, prevented the association between RalA and Arf. Brefeldin A, which inhibits Arf GDP-GTP exchange, inhibited PLD activity in v-Src- and v-Ras-transformed cells but not in the nontransformed cells, suggesting that the association of Arf with RalA is required for the increased PLD activity induced by v-Src and v-Ras. These data implicate Arf in the transduction of intracellular signals activated by v-Src and mediated by the Ras-RalA GTPase cascade. Because both Arf and PLD1 stimulate vesicle formation in the Golgi, these data raise the possibility that vesicle formation and trafficking may play a role in the transduction of intracellular signals.

3T3 Cells↗
PubMed1998

Timing of onset of contraceptive effectiveness in Depo-Provera users: Part I. Changes in cervical mucus.

OBJECTIVE: To evaluate the changes in cervical mucus within the first hours or days after depot medroxyprogesterone acetate (MPA) injection so as to estimate the time at which cervical mucus becomes hostile enough to prevent pregnancy. DESIGN: Multicenter, clinical descriptive study. SETTING: Family planning clinic. PATIENT(S): Thirty women who were between days 8 and 13 of their menstrual cycle and who had requested Depo-Provera were enrolled in the study. INTERVENTION(S): Cervical mucus and blood samples were obtained; transvaginal ultrasonography was performed. MAIN OUTCOME MEASURE(S): Cervical mucus scores, sperm penetration distances, ovarian follicular size, and serum levels of progesterone and estradiol. RESULT(S): From 6 to 24 hours after injection, there was a sharp decline in the cervical mucus score for most of the subjects. All subjects exhibited poor mucus on day 3 after injection, and by day 7, all subjects had zero scores, with the exception of two outliers on each day. Sperm penetration, as measured by the vanguard sperm distance, was already poor (< 1 cm) in 7 of the 30 subjects at the time of injection and was reduced progressively up to 24 hours after injection, when only four subjects had a sperm penetration of > 1 cm. A rapid decline in the estimated number of sperm was observed at 12 hours and more so at 24 hours in the majority of subjects. CONCLUSION(S): The data presented in this report confirmed that depot MPA causes profound changes in cervical mucus after injection. Although very little change was seen at 6 hours, alterations were observed subsequently, with 90% of the subjects showing a poor cervical mucus score 24 hours after administration of the progestin. No reliable clinical marker is available to identify in which women depot MPA might exert its effect on cervical mucus within 3 days. Thus, we believe that at present, women should be informed of this uncertainty and should use a backup method of contraception for 7 days when the first injection of depot MPA is provided after the seventh day of the menstrual cycle.

Adult↗
PubMed1998

Timing of onset of contraceptive effectiveness in Depo-Provera users. II. Effects on ovarian function.

OBJECTIVE: To determine the timing of onset of contraceptive effectiveness after the first injection of 150 mg of depot medroxyprogesterone acetate (DMPA) administered between days 8 and 13 of the menstrual cycle. DESIGN: Descriptive, prospective study. SETTING: A tertiary university referral center. PATIENT(S): Thirty healthy women between 18 and 40 years of age. INTERVENTION: Volunteers were injected with DMPA between days 8 and 13 (5 women on each day) of the menstrual cycle. MAIN OUTCOME MEASURE(S): Ovarian function determined by serum levels of E2 and progesterone and follicular development evaluated by vaginal ultrasound. RESULT(S): In nine (30%) of 30 women studied, DMPA did not prevent ovulation. All ovulations occurred in women receiving DMPA between days 10 and 13 of the cycle. No woman who received injections on day 8 or 9 ovulated. Ovulation suppression was more effective in women with low ovarian activity. All ovulation occurred within 3 days after the injection. CONCLUSION: A back-up contraceptive method, used after the 7th day of the menstrual cycle, is recommended for up to 7 days after the first injection of DMPA.

Adolescent↗
PubMed1998

Enterobacter cloacae and Pseudomonas aeruginosa polymicrobial bloodstream infections traced to extrinsic contamination of a dextrose multidose vial.

OBJECTIVE: To identify risk factors for polymicrobial bloodstream infections (BSIs) in neonatal intensive care unit (NICU) patients during an outbreak of BSIs. DESIGN: During an outbreak of BSIs, we conducted a retrospective cohort study, assessed NICU infection control practices and patient exposure to NICU healthcare workers (HCWs), and obtained cultures of the environment and HCW hands. PATIENTS: During the period May 3 to 7, 1996, 5 infants contracted BSIs caused by both Enterobacter cloacae and Pseudomonas aeruginosa, and one infant contracted a BSI caused by E cloacae only. For each pathogen, all isolates were identical on DNA typing. RESULTS: Infants exposed to the following were more likely than nonexposed infants to have BSI: umbilical venous catheters (6/14 vs 0/7, P = .05), total parenteral nutrition given simultaneously with a dextrose/electrolyte solution (6/12 vs 0/9, P = .02), or one HCW (5/7 vs 1/13, P = .007). Neither environmental nor HCW hand cultures yielded the outbreak pathogens. Quality control cultures of intravenous solution bags were negative. CONCLUSIONS: We speculate that a dextrose multidose vial became contaminated during manipulation or needle puncture and that successive use of this contaminated vial for multiple patients may have been responsible for BSIs. Aseptic techniques must be employed when multidose vial medications are used. Single-dose vials should be used for parenteral additives whenever possible to reduce the risk of extrinsic contamination and subsequent transmission of nosocomial pathogens.

Bacteremia↗
PubMed1998

Detection of bovine milk proteins in soymilk by Western blotting.

A Western blotting method for the detection of whey milk proteins in commercial soymilks was applied to assess the food safety. Soy proteins and milk proteins were separated by SDS-PAGE in PhastSystem equipment. After the electrophoretic separation, immunodetection with anti-bovine alpha-lactalbumin and anti-bovine beta-lactoglobulin antisera was performed. Adulteration with bovine protein in percentages of 0.1% in soy protein can be detected. Western blotting of bovine alpha-lactalbumin and bovine beta-lactoglobulin was applied to detect adulteration by bovine milk proteins in different soymilks: powdered soymilk and soy infant formulas.

Animals↗
PubMed1998

Technetium-99m-labeled anti-EGF-receptor antibody in patients with tumor of epithelial origin: I. Biodistribution and dosimetry for radioimmunotherapy.

UNLABELLED: Accurate estimation of biodistribution and absorbed dose to normal organs and tumors is important for immunoscintigraphic studies and radioimmunotherapy treatment planning. METHODS: Four patients (3 men, 1 woman; mean age 54.8 +/- 9.2 yr; range 42-64 yr) were administered 3 mg of anti-human epidermal growth factor receptor (anti-hEGF-r) antibody (ior egf/r3), radiolabeled with 99mTc activity of 39.5 +/- 1.1 mCi (range 38.5 mCi-40.7 mCi) by intravenous bolus infusion. After administration, blood and urine samples were collected from three patients up to 24 hr after injection. Whole-body anterior and posterior scans were obtained at 5 min and 1, 3, 5 and 24 hr after injection. Using a computer program, regions of interest were drawn over the heart, liver, spleen, bladder and tumor to measure the activity in the source organs at each scanning time. Time-activity curves for each source organ were then fitted to monoexponential or biexponential functions by nonlinear least squares regression using the flexible polyhedrals method, which adequately fit our data with the correlation coefficient of 0.985 +/- 0.013, and were integrated to determine organ residence times. The mean absorbed doses to the whole body and various normal organs were then estimated from residence times and from blood and urine samples using the methods developed by the Medical Internal Radiation Dose Committee. The effective dose equivalent and effective dose were calculated as prescribed in ICRP Publication Nos. 30 and 60. RESULTS: Plasma disappearance curves of 99mTc-labeled anti-hEGF-r antibody were best-fit by a two-compartment model in all patients with a distribution half-life (t(1/2alpha)) of 0.207 hr +/- 0.059 hr (mean +/- s.d., n = 3) and an elimination half-life (t(1/2beta)) of 13.9 hr +/- 2.2 hr. Among the various organs, significant accumulation of the radiolabeled antibody was found in the liver (48.5% +/- 4.4%, mean +/- s.d.), heart (3.50% +/- 0.17%) and spleen (3.1% +/- 1.8%) at 5 min postadministration. These values were reduced to 3.2% +/- 0.4%, 0.1% +/- 0.01% and 0.1% +/- 0.1%, respectively, at 24 hr. Mean cumulative urinary excretion of 99mTc-labeled anti-hEGF-r antibody was 4.6% +/- 0.6% at 24 hr postinjection. Estimates of radiation absorbed dose to normal organs in rad/mCi administered (mean +/- s.d., n = 4) were: whole body 0.017 +/- 0.002; gallbladder wall 0.074 +/- 0.007; spleen 0.136 +/- 0.076; and liver 0.267 +/- 0.036. The effective dose equivalent and effective dose estimates for adults were 0.041 +/- 0.008 rem/mCi and 0.027 +/- 0.004 rem/mCi administered. CONCLUSION: This feasibility study indicates that 99mTc-labeled anti-hEGF-r antibody (ior egf/r3) can be used safely; this analysis provides a dosimetric framework for future studies. This monoclonal antibody, labeled with 188Re, could possibly permit a successful regional radioimmunotherapy of tumors of epithelial origin.

Adult↗
PubMed1998

[Use of 99mTc-tetrofosmin scintigraphy in the diagnosis of patients with hyperparathyroidism].

UNLABELLED: The aim of the work was to study the diagnostic value of 99mTc-tetrofosmin to localize anomalous parathyroid glands in patients with hyperparathyroidism. METHODS: We have studied 33 patients: 12 with primary and 21 with secondary hyperparathyroidism, 9 of them renal graft recipients. Sixteen patients underwent surgery, 12 with primary and 4 with secondary hyperparathyroidism. All patients were injected with 740 MBq of 99mTc-tetrofosmin. Subsequently at 15, 30 and 60 minutes images were acquired for 300 seconds using a pin-hole collimator. A pertechnetate thyroid scintigraphy was obtained in 7 cases (24-48 h later) when the thyroid activity made difficult the identification of parathyroid glands. RESULTS: In the group of patients with primary hyperparathyroidism, all cases showed a focal uptake in lower right localization. In the secondary hyperparathyroidism group, 12 patients showed diffuse tracer uptake in two or more glands and histology confirmed hyperplasia in four of them. Seven cases showed a greater focal uptake in a gland: two of them were renal graft recipients and three were chronic renal failure cases in haemodyalisis, and two were evaluated postsurgery showing uptake in the remnant parathyroid gland. The two remaining patients had a normal scintigraphy and corresponded to two false negative cases. In conclusion, our results suggest that 99Tc-tetrofosmin may be used as a suitable tracer for preoperative detection and screening of anomalous parathyroid glands.

Adenoma↗