Biomedical subjects

M Ramos

Publications and source records attributed to M Ramos.

At least 19 recordsLinked to original sources

PubMed1995

Quantitative analysis of major whey proteins by capillary electrophoresis using uncoated capillaries.

A method that allows separation and quantitation of the main whey proteins by capillary electrophoresis using uncoated capillaries is proposed. Separations are performed using 100 mM borate buffer, pH 8.2, containing 30 mM sodium sulfate. The use of high pH and high ionic strength buffer reduces adsorption of proteins on the capillary wall, making their separation possible. Reproducibility of migration times and areas of peaks are improved by optimizing the capillary equilibration protocol and by using an internal standard. Relative standard deviations ranging between 0.74 and 1.03% for migration times and 2.14 to 5.23% for areas of major peaks are obtained. Detection limits equal to or lower than 0.5 mg/100 mL are achieved. Linear relationships of peak area versus concentration have been used to quantitate bovine serum albumin (BSA), alpha-LA (alpha-lactalbumin), beta-LG A (beta-lactoglobulin A) and beta-LG B (beta-lactoglobulin B) in cow's milk subjected to different thermal treatments. Electrophoretic profiles of these milk samples show peaks from other peptides besides those from main proteins. Characteristic patterns for whey from different species are obtained.

Animals↗

PubMed1995

Simultaneous administration of 111In-human immunoglobulin and 99mTc-HMPAO labelled leucocytes in inflammatory bowel disease.

Technetium-99m hexamethylpropylene amine oxime (HMPAO) labelled leucocytes and indium-111 polyclonal immunoglobulin (IgG) were simultaneously injected into a group of 27 patients routinely referred for the investigation of inflammatory bowel disease (IBD). Ten-minute anterior abdomen and tail on detector views were obtained at 30 min, 4 h and 24 h p.i. of both tracers. The diagnosis of IBD was obtained in all cases by endoscopy with biopsy and/or surgery. Images were blindly evaluated by two experienced observers who only knew of the clinical suspicion of IBD. IBD was confirmed in 20 patients (12 with Crohn's disease and eight with ulcerative colitis). Sensitivity, specificity and accuracy were 100%, 85% and 96% respectively for labelled leucocytes and 70%, 85% and 74% for IgG. Both IgG and leucocyte scans were normal in six out of seven patients in whom a diagnosis of IBD was excluded; the remaining patient, with ischaemic colitis, was falsely positive with both agents. As far as disease extension is concerned, the IgG study localized 27 diseased segments, whereas 49 were seen with the leucocyte study. Eighty-four segments were normal and 25 showed tracer uptake with both agents. Twenty-four were positive only with the leucocyte study and two were positive only with the IgG study. Agreement between the agents was 80.7%. These results confirm that 111In-human polyclonal scintigraphy is less sensitive than 99mTc-HMPAO scintigraphy both for the diagnosis of IBD and in the evaluation of disease extension. Nevertheless, if leucocyte labelling is not available, labelled IgG can be used only for diagnostic purposes.

Adolescent↗

PubMed1995

Presence of curarizing polypeptides and a pancreatitis-inducing fraction without muscarinic effects in the venom of the Venezuelan scorpion Tityus discrepans (Karsch).

Four toxic polypeptidic fractions (TdF-I-IV) were purified from the venom of the Venezuelan scorpion Tityus discrepans by means of gel filtration on Sephadex G'-50. The peptides have mol. wts of approx. 6000 and normalized elution volumes (Vn = Elution volume/Total column volume) of: TdF-I = 0.27 (0.26, 0.28), n = 13; TdF-II = 0.40 (0.39, 0.41), n = 15; TdF-III = 0.57 (0.56, 0.59), n = 14, and TdF-IV = 0.68 (0.67, 0.70), n = 13 (median and its 95% confidence interval, n = number of elutions used to calculate the median). Mice (white, male, 16-19 g, IVIC strain) were injected with these fractions and sacrificed 48 hr later. No toxicity was observed when fraction I (0.93 microgram/g mice) or IV (2.51 micrograms/g mice) was injected i.p. into mice. TdF-II (9 to 50 micrograms/g mice) produced sialorrhea, dyspnea and death 1 hr after i.p. injection. Light microscopy of the pancreas revealed that TdF-III (3.42 micrograms/g mice) produced structural modifications such as acinar cell vacuolization, degranulation and interstitial swelling; these changes are characteristic of acute pancreatitis. No effects on the islets of Langerhans or the pancreatic ducts were observed. TdF-III had no overt muscarinic effects when injected i.p. into mice. On the neuromuscular preparation of the frog (Hyla crepitans) TdF-I blocked neuromuscular transmission at the postsynaptic membrane; TdF-II depolarized the muscle membrane by opening sodium channels and TdF-IV prolonged action potentials, suggesting potassium channel blockage.

Action Potentials↗

PubMed1995

Two dimensional electrophoresis and immunoblotting for the study of ovine whey protein polymorphism.

Different electrophoretic techniques have been applied to the study of ovine whey protein polymorphism. Isoelectric focusing (IEF) over the pH gradient 3.5-9.5 was a suitable method for resolving both genetic variants of ovine beta-lactoglobulin (beta-lg); using this type of IEF, ovine beta-lg A seemed to be defined by a major and a minor 'satellite' band. Approximate isoelectric point, relative molecular mass, amino acid composition and N-terminal sequence of this minor band were determined. A good separation of ovine beta-lg was achieved using ultrathin layer isoelectric focusing (UTLIEF) over the pH gradient 2.5-7.0. However, addition of urea in UTLIEF gels led to some differences in the patterns of the ovine whey proteins when compared with those obtained by IEF on gels not containing urea. Two dimensional electrophoretic techniques provided a considerable separation of ovine whey proteins. Immunoblotting applied to a two dimensional separation permitted the identification of the bands belonging to beta-lg and alpha-lactalbumin fractions.

Amino Acids↗

PubMed1995

The influence of human chorionic gonadotrophin administration upon the next ovarian cycle.

We examined the influence of human chorionic gonadotrophin (HCG), used as an ovulation inducer and/or for supporting the luteal phase, on the next ovarian cycle. Four women received 10,000 IU of HCG at mid-cycle and another four received the same dose plus 1500 IU on the 17th, 19th and 21st days of the cycle. In the menstrual cycle prior to our experiments, venous blood samples were collected and vaginal ultrasound of the ovaries was performed every other day from day 21-28; the same data were also collected on days 1-10 of the experiment cycle. In such a way, control values were obtained. After the administration of HCG, venous blood samples were collected and ultrasound was performed in the same way and on the same days as in the controls. Follicle stimulating hormone (FSH) and luteinizing hormone were determined by radioimmunoassay in all blood samples, and HCG only in samples collected after the experiment. The results showed that only FSH was lower in the late luteal phase after the administration of 10,000 IU of HCG. Follicular diameters were higher during the follicular phase than during the previous cycle only in women who received the low dose of HCG. In addition, one woman presented with detectable HCG in the following ovarian cycle. The use of HCG in the preceding cycle may reduce FSH and develop persistent follicles in the subsequent cycle. We suggest that an ultrasound of the ovaries should be performed before starting a new ovulation induction cycle in a woman who has received HCG in the previous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Clomiphene↗

PubMed1995

Staphylococcus aureus induces platelet aggregation via a fibrinogen-dependent mechanism which is independent of principal platelet glycoprotein IIb/IIIa fibrinogen-binding domains.

Platelet aggregation by bacteria is felt to play an important role in the pathogenesis of infective endocarditis. However, the mechanisms involved in bacterium-induced platelet aggregation are not well-defined. In the present study, we examined the mechanisms by which Staphylococcus aureus causes rabbit platelet aggregation in vitro. In normal plasma, the kinetics of S. aureus-induced platelet aggregation were rapid and biphasic. The onset and magnitude of aggregation phase 1 varied with the bacterium-platelet ratio, with maximal aggregation observed at a ratio of 5:1. The onset of aggregation phase 2 was delayed in the presence of apyrase (an ADP hydrolase), suggesting that this later aggregation phase may be triggered by secreted ADP. The onset of aggregation phase 2 was delayed in the presence of prostaglandin I2-treated platelets, and this phase was absent when paraformaldehyde-fixed platelets were used, implicating platelet activation in this process. Platelet aggregation phase 2 was dependent on S. aureus viability and an intact bacterial cell wall, and it was mitigated by antibody directed against staphylococcal clumping factor (a fibrinogen-binding protein) and by the cyclooxygenase inhibitor indomethacin. Similarly, aggregation phase 2 was either delayed or absent in three distinct transposon-induced S. aureus mutants with reduced capacities to bind fibrinogen in vitro. In addition, a synthetic pentadecapeptide, corresponding to the staphylococcal binding domain in the C terminus of the fibrinogen delta-chain, blocked aggregation phase 2. However, phase 2 of aggregation was not inhibited by two synthetic peptides (alone or in combination) analogous to the two principal fibrinogen-binding domains on the platelet glycoprotein (GP) IIb/IIIa integrin receptor: (i) a recognition site on the IIIa molecule for the Arg-Gly-Asp (RGD) sequence of the fibrinogen alpha-chain and (ii) a recognition site on the IIb molecule for a dodecapeptide sequence of the fibrinogen delta-chain. This differs from ADP-induced platelet aggregation, which relies on an intact platelet GP IIb/IIIa receptor with an accessible RGD sequence and dodecapeptide recognition site for fibrinogen. Furthermore, a monoclonal antibody directed against the RGD recognition site on rabbit platelet GP IIb/IIIa receptors failed to inhibit rabbit platelet aggregation by S. aureus. Collectively, these data suggest that S. aureus-induced platelet aggregation requires bacterial binding to fibrinogen but is not principally dependent upon the two major fibrinogen-binding domains on the platelet GP IIb/IIIa integrin receptor, the RGD and dodecapeptide recognition sites.

Adenosine Triphosphate↗

PubMed1995

[Hepatitis E].

Explore the source record for details and available documents.

Adolescent↗

PubMed1994

Differential effects of guanine nucleotides on kainic acid binding and on adenylate cyclase activity in chick optic tectum.

In G protein-coupled receptors, neurotransmitter-induced binding of GTP to G proteins triggers the activation of effector systems while simultaneously decreasing the affinity of the transmitter for its specific binding site within the receptor-G protein complex. In the present study we show that, in the chick optic tectum, guanine nucleotides inhibit the binding of the glutamate analog, kainate, and activate adenylate cyclase by different mechanisms and acting on different sites. GMP-PNP, a non-hydrolyzable analog of GTP, binds tightly to G proteins so that the binding is stable even after exhaustive washing. By use of this property, we have prepared membrane samples in which G protein GTP-binding sites are pre-saturated with GMP-PNP. Experiments carried out with these membranes show that GMP-PNP, GDP-S and GMP inhibit the binding of [3H]kainate by interacting with site(s) unrelated to G proteins, whereas GMP-PNP activates adenylate cyclase activity by binding to G proteins.

Adenylyl Cyclases↗

PubMed1994

Changes in furosine and proteins of UHT-treated milks stored at high ambient temperatures.

Changes in furosine, undenatured whey protein content, and proteolysis during 90 days storage at 20, 30, and 40 degrees C of UHT-processed milk were studied. Furosine increased as the temperature and storage time increased. The peptide concentration increased during the storage period, being faster at 30 degrees C than at 20 or 40 degrees C. High-performance liquid chromatographic analysis of undenatured whey proteins showed considerable changes in the shape of the peaks during storage.

Animals↗

PubMed1994

Glomus tumor of the female external genitalia: a report of two cases.

Glomus tumors occurring in the external genitalia of two women aged 53 and 46 years, respectively, are reported. One of the tumors was clitoral and the other arose in the periurethral area of the vulva. The diagnosis in one case was supported by immunocytochemical analysis. Electron microscopy was performed on both tumors. Only two glomus tumors involving the female external genitalia have been reported in the literature. The tumors we describe appeared to be morphologically similar to the glomus tumors that typically arise in the distal extremities.

Female↗

PubMed1994

Haematological effects of postoperative autotransfusion in spinal surgery.

A prospective, randomized, controlled study was performed to determine the haematological and biochemical changes and clinical safety of postoperative autotransfusion (Solcotrans Orthopedic Plus system) in patients undergoing spinal surgery. Fifty patients were studied and were randomly allocated to Control (n = 25) and Solcotrans (n = 25) groups. Both groups had their postoperatively drained blood collected into the Solcotrans reservoir but only the Solcotrans group had this salvaged blood considered for reinfusion. After a 5-h postoperative collection period, analysis of the shed blood showed a haematocrit of 0.26 +/- 0.11, few platelets (80 +/- 63 10g.l-1), a fibrinogen level of less than 0.1 g.l-1 and a high level of D-dimers. The salvaged blood did not clot and aerobic and anaerobic culture produced no growth. The volume of blood collected was greater than 200 ml in 21 patients in the Solcotrans group who were autotransfused (384 +/- 101 ml, range 200-600 ml), and in 16 patients in the Control group. Within 15 min following completion of reinfusion of the salvaged blood there was a significant, but moderate decrease in platelet count (181 +/- 74 vs 223 +/- 90 10g.l-1, P < 0.001) and fibrinogen concentrations (2.1 +/- 0.8 vs 2.3 +/- 0.9 g.l-1, P < 0.02), and an increase in circulating D-dimers (P < 0.001) and plasma free haemoglobin concentrations (236 +/- 155 vs 82 +/- 79 mg.l-1, P < 0.001). Prothrombin time (PT) and activated partial thromboplastin time (APTT) did not increase, and potassium concentrations were not significantly affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood↗

PubMed1994

Transcranial Doppler sonography in headache-free migraineurs.

We used transcranial Doppler ultrasonography to determine whether intracranial blood velocities in 182 headache-free migraineurs (60 with aura, 122 without aura) differed from velocities in 38 nonheadache prone control subjects. During the headache-free period, migraineurs with and without aura had significantly elevated mean velocities in all intracranial arteries except the right internal carotid artery at the level of the siphon. Velocities in migraineurs with aura did not differ significantly from velocities in those without aura. Markedly increased velocities were noted in a subset of interictal migraineurs. Two explanations are possible: 1) Blood flow velocities may increase in response to a decrease in the cross sectional area of a vessel at or near the point of insonation. 2) Alterations at the level of the cerebral arteriole may affect regional cerebral blood flow, thereby changing blood flow velocities at the point of insonation. Transcranial Doppler sonography alone cannot sort out which process is responsible for the vascular response. This work may have therapeutic as well as diagnostic implications. When interictal flow velocities are markedly increased, it is possible that therapeutic agents with vasoconstrictor action might cause an excessive response. Further study is needed to clarify the sites of vasoreactivity as well as the magnitude of drug-induced vasoconstrictor response.

Adult↗

PubMed1994

Gas-liquid chromatography of cellular fatty acids for identification of staphylococci.

A commercially available, computer-assisted microbial identification system (MIS) employs gas-liquid chromatographic analyses of bacterial fatty acids. The MIS was used to identify 470 isolates of Staphylococcus species. The accuracy of the MIS was compared with the accuracies of conventional methods. There was a complete agreement between the MIS and conventional methods in the identification of 413 (87.8%) strains. For 36 of 45 misidentified strains, the correct identification was listed by the MIS as a choice but not as the first choice. Twelve strains could not be matched. All strains of Staphylococcus cohnii, S. epidermidis, S. intermedius, S. lugdunensis, S. schleiferi, S. sciuri, S. simulans, and S. xylosus were correctly identified. Two species, S. hominis and S. saprophyticus, accounted for 52.6% (30 of 57) of the misidentifications. Seventy-eight organisms were retested. Identification of 73 organisms remained unchanged, and for five organisms, the second choice became first and vice versa. The overall performance of the MIS is acceptable, and the system can be used as an alternate identification method for staphylococci.

Chromatography, Gas↗

PubMed1994

Diminished virulence of a sar-/agr- mutant of Staphylococcus aureus in the rabbit model of endocarditis.

Microbial pathogenicity in Staphylococcus aureus is a complex process involving a number of virulence genes that are regulated by global regulatory systems including sar and agr. To evaluate the roles of these two loci in virulence, we constructed sar-/agr- mutants of strains RN6390 and RN450 and compared their phenotypic profiles to the corresponding single sar- and agr- mutants and parents. The secretion of all hemolysins was absent in the sar-/agr- mutants while residual beta-hemolysin activity remained in single agr- mutants. The fibronectin binding capacity was significantly diminished in both single sar- mutants and double mutants when compared with parents while the reduction in fibrinogen binding capacity in the double mutants was modest. In the rabbit endocarditis model, there was a significant decrease in both infectivity rates and intravegetation bacterial densities with the double mutant as compared to the parent (RN6390) at 10(3)-10(6) CFU inocula despite comparable levels of early bacteremia among various challenge groups. Notably, fewer bacteria in the double mutant group adhered to valvular vegetations at 30 min after challenge (10(6) CFU) than the parent group. These studies suggest that both the sar and agr loci are involved in initial valvular adherence, intravegetation persistence and multiplication of S. aureus in endocarditis.

Animals↗

PubMed1994

[Inflammatory pseudo tumor of the bladder (in a 6-month-old girl)].

We describe the clinical case of a six-month old female child, who presented an intra-vesical mass as a sequence of urinary tract infection. After surgical resection the histopathological study was consistent with the diagnosis of inflammatory pseudotumor of the bladder.

Cystitis↗

PubMed1994

[S. pneumoniae sternoclavicular arthritis in a patient with HIV infection].

HIV infection is a predisposing factor for pneumococcic infection. While pneumonia is the most frequent location, other locations (articular, meningeal, endocardiac, etc) have been less frequently described. Among the articular infections described in patients with HIV infection, the sternoclavicular affection is extremely rare and it usually develops in association with parenterally drug addiction, being Staphylococcus aureus and Pseudomonas aeruginosa the most frequently germs involved. We describe the first case of sternoclavicular arthritis by Streptococcus pneumoniae in a patient with HIV infection. In our case, the chronic hepatopathy associated to alcohol consumption is a predisposing factor related to the pneumococcic infection. Our case suggests the need to formally investigate the HIV infection in young patients with invasive pneumococcic infection.

Adult↗

PubMed1994

[Sjögren's syndrome].

This paper consists the theorical review and the current concepts of the subject and the second includes the casuistry of the Stomatology Department of the Pulido Valente Hospital. From April 1989 to 1991 (2 years), a study was made on Sjögren Syndrome (Primary and Secondary) of multiple character with the particular co-operation of the Portuguese Institute of Rheumatology. With this paper we wish to point out the importance of the oral evaluation of the study of the plurisystemic diseases as well as to establish criterions of diagnosis for the Portuguese population. Eighty cases of suspected Sjögren's Syndrome have been assessed, 66 of which have been fully. The reason for the consultation was dry mouth, dry eyes and enlargement of parotid glands. The symptoms were isolated or in association with other pathologies after other causes had been excluded. We had to establish the salivary reference values for the Portuguese population in 22 healthy volunteers. The xerostomia was evaluated by the Sialochemistry, Sialography, Cintigraphy and biopsies of the lower lip and of the sublingual gland. The ophthalmologic examination took place in the Ophthalmology Department of Santo António dos Capuchos Hospital by means of Shirmer test, Rosa Bengala and B.U.T. In spite of Sjögren's Syndrome being, up to now, so remotely determined in connection with the treatment, these patients need medical care and Stomatology plays a fundamental role as far as the diagnosis and the therapeutic points of view are concerned. We maintain the notion that the Syndrome is not as infrequent as one would believe and the evaluation of the oral field is important to establish the degree of the disease and its treatment.

Female↗

PubMed1994

Chromosome 17 abnormalities and TP53 mutations in adult soft tissue sarcomas.

This study was designed to determine the frequency of structural genetic abnormalities of chromosome 17 and the incidence of TP53 mutations as they relate to the biological behavior of adult soft tissue sarcomas. We analyzed a group of 73 soft tissue sarcomas of adults that were clinically and pathologically well characterized using molecular genetic techniques and expression studies. We then correlated genotype and phenotype with pathological parameters. Overall, allelic loss of 17p and 17q was identified in 53 and 29% of informative cases, respectively. p53 nuclear overexpression was detected in 34% of the tumors analyzed. We observed an association between 17p deletions and tumor presentation being more frequent in recurrent and metastatic tumors than primary lesion. p53 nuclear overexpression was associated with tumor grade, size, and more frequently detected in metastatic than primary sarcomas. The 11 intragenic mutations characterized included 10 cases of single base substitution and one single base deletion; 8 were of the missense type and 3 were nonsense. It is concluded that 17p deletions and TP53 mutations are common events in adult soft tissue sarcomas and that due to the trends observed with the cohort of patients analyzed they may become prognostic markers for patients affected with these tumors.

Alleles↗