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Biomedical subjects

M Rojas

Publications and source records attributed to M Rojas.

194 records · Page 11Linked to original sources
PubMedDate not supplied

Cytokeratin, vimentin and E-cadherin immunodetection in the embryonic palate in two strains of mice with different susceptibility to glucocorticoid-induced clefting.

An immunohistochemical study analyzing the pattern of distribution of some intermediate filament proteins, keratin and vimentin and, one adhesion molecule, cadherin in different stages of developing secondary palate in two strains of mice with different H-2 backgrounds was undertaken to investigate differences between a strain that is susceptible to glucocorticoid-induced cleft palate (A/Sn) and one that is resistant to glucocorticoid-induced cleft palate (C57/BL). The heads of embryos were processed by standard immunohistochemistry with antipancytokeratin (KAE1), antikeratins 18 (K18) and 19 (K19), antivimentin, and anti E-cadherin antibodies. Immunostaining with KAE1 antibody showed differences between the strains. The reaction was stronger in the medial edge epithelia of palatal processes in the A/Sn strain at all stages of palatogenesis. The C57/BL strain showed a weak immunostain to KAE1. Antivimentin antibody stained the mesenchymal cells of palatal processes and K18 and K19 showed no reaction in either strain of mice. Anti E-cadherin antibody was detected in the medial palatal epithelium of both strains of mice and in all stages of palate development. No differences were observed in E-cadherin and vimentin immunostain in palatal epithelium between the strains. The different expression of some cytokeratins in the embryonic palatal epithelium suggests that these intermediate filament proteins may be involved in different susceptibility to glucocorticoid-induced cleft palate in the mouse. The decreased immunoreaction of cytokeratins observed in the resistant strain would facilitate the disappearance of this molecule during the transformation from an epithelial to a mesenchymal phenotype that takes place during the development of the palate. These results may be related to the loss of cytokeratin expression observed during epithelial-mesenchymal transformation in the embryonic palate.

Animals↗
PubMedDate not supplied

[Role of magnetic resonance in shoulder disease].

Next to the knee, the shoulder is the most common joint to be referred for MRI. Excellent soft tissue contrast and multiplanar acquisition provide optimal assessment of muscle, tendons, hyaline and fibrous cartilage, joint capsule, fat, bursae and bone marrow. In this article the most common indications for shoulder MRI are reviewed and discussed, but we focused primarily on the rotator cuff syndrome and shoulder instability. Correct diagnosis requires the use of appropriate pulse sequences and imaging planes, proper patient positioning, and a satisfactory surface coil. Moreover, technical improvements continuously augment the ability of MRI to study the shoulder; for example Magnetic Resonance arthrography is superior to the other imaging techniques in evaluation of glenohumeral joint. This interdependence between technical development in MRI and clinical advance in shoulder therapy ensures that MRI will continue to play an important role in the routine management of patients with shoulder disease.

Humans↗
PubMedDate not supplied

[New CT and MR imaging techniques in non-traumatic neurological emergencies].

New CT and MR imaging techniques used for non-traumatic neurologic emergencies (represented mostly by ischemic stroke) fulfil the exigency to know quickly and with high accuracy the presence of abnormalities in cerebral perfusion, with the final aim to practise immediately all the treatments needed to prevent the progression of the neurologic damage, by selecting those patients to undergo fibrinolysis, which is useless and not indicated in many occasions. The diagnosis of ischemia is only the first goal reached by these new diagostic tools, while it is nowdays possible and required to stratify the risk factors for the therapy and to accurate select those patients candidates to fibrolnilysis, in order to minimize the risck related to the inadequate treatment choice.

Brain↗
PubMedDate not supplied

[Acute poisoning with thyroxine in children].

Two girls aged 5 and 14 years were admitted to hospital after ingestion of L-thyroxine in estimated doses of 72 micrograms.kg and 118 micrograms.kg in the preceding 4 and 8 hours, respectively. Both had high serum T4 (19 and 20 micrograms/dl) and were asymptomatic at the time of admission and both were treated with Iopanoic acid 3 g orally every 72 hours, in order to block the conversion of T4 into T3. Serum levels of T4 were still elevated for up to ten days (8 and 16 micrograms/dl, respectively at day 10), but serum levels of T3 came down to 60 micrograms/dl within the first 48 hours of treatment in both cases. It should be taken into account that these patients may be initially asymptomatic and that symptoms may appear even later than 24 hours after the ingestion, so they should be admitted and treated at hospital. Iopanoic acid has been proved to be a treatment of choice in order to block the conversion of T4 into T3.

Administration, Oral↗
PubMedDate not supplied

[Cytologic diagnosis of abdominal lesions with fine needle aspiration guided by ultrasound].

The purpose of this work was to analyse the advantages and disadvantages of puncture-aspiration with fine needle, guided by ultrasonography, trying to determine its usefulness in our hospitals and its reliability in the diagnosis of intraabdominal lesions of different locations. 29 punctures were practiced on 19 patients, 9 women and 10 men of ages comprised between 34 and 94 years, with lesions in different organs of the abdominal cavity diagnosed by ultrasonography with real time equipment and lineal 3.5 and 5 MHz transducers. After cleaning and antisepsis a Chiba needle is introduced under ultrasonographic vision, up to the location of the lesion, the guide is removed and under a negative pressure, the sample is taken, which is later dried into the air and coloured using the May-Grünwald-Giemsa Technique. Only in one case it was not possible to obtain adequate material for the cytological study. There were 11 positive cases for malignity and 7 negative, one of which was a false negative. The sensibility of the method was of 91.6% with a specificity of 100% and a reliability of 89.4%. We definitely believe that the method is practical, very easy to carry out in our hospitals with a minimum amount of risk, and most of all, dependable to clarify certain diagnoses.

Abdominal Neoplasms↗
PubMedDate not supplied

[Ultrasonography as diagnostic method in abdominal trauma and wounds].

Abdominal trauma is a public health problem. Early diagnosis of this lesion is directly related to the survival of these patients. Ultrasonography is a good method for the study of the traumatized patient. Abdominal ultrasonography was performed in 35 patients seen at the Central Military Hospital of Caracas during the years 1987-1988. Free liquid in the abdominal cavity and parenchymatous hematomas were the most frequent findings followed by retroperitoneal hematomas. Abdominal ultrasonography performed by trained and experienced personnel can be of great help in the management of patients with abdominal trauma. Correlation between ultrasonography, surgical findings and the clinical follow up was 100%. We recommended this method for the initial evaluation of these patients.

Abdominal Injuries↗
PubMedDate not supplied

Axillary-subclavian venous thrombosis.

From 1974 through 1984 six patients with axillary-subclavian venous thrombosis were studied and treated. This disorder represents 1% of the various types of venous thrombosis reported in the literature. Symptoms appeared following effort in four patients, while a cervical rib and a scar bridle after radical mastectomy were identified as the underlying cause in two patients. Ages ranged from 17 to 59 years, with a mean age of 33 and equal sex distribution. None of the six patients had blood clotting defects. The diagnosis was based on clinical evaluation and was confirmed by phlebography. There was edema and functional impairment of the arm in all cases. Pain and venous prominence was found in 83%, rubor of the extremity in 66%, local hyperthermia in 50%, and arterial compression in 33%. Five patients were treated with anticoagulants and bed rest. Surgery was performed in two patients with thoracic outlet syndrome. First rib resection with scalenotomy was performed in one case and cervical rib resection with scalenotomy in the other. After a mean follow-up of 13 months, the results were good in four and average in two patients.

Adolescent↗
PubMedDate not supplied

Failure to induce nitric oxide production by human monocyte-derived macrophages. Manipulation of biochemical pathways.

Production of nitrix oxide (NO-) by human macrophages is controversial. In the present study, the ability of human monocyte-derived macrophages (M phi) to produce NO- in response to M phi modulators was tested. M phi cultured for up to nine days and stimulated for 48 with different concentrations of LPS and/or IFN-gamma failed to produce significant amounts of NO2- compared to unstimulated cultures. Inhibition of the cyclo-oxygenase pathway with indomethacin did not increase NO2- production by LPS stimulated M phi. Since human M phi lack biopterin, needed for NO- synthesis by murine M phi, human M phi stimulated with LPS plus IFN-gamma were additionally cultured in the presence of neopterin or biopterin. These treatments did not induce NO2- production. Furthermore, simultaneous treatment with indomethacin and neopterin or biopterin also failed to induce NO2- production. However, human M phi, stimulated with IFN-gamma and LPs, produced TNF-alpha suggesting that the lack of increment in NO2- production was not due to an absence of response of M phi to the stimuli used. As an indirect approach to explore the NO- production, human M phi were infected with virulent Mycobacterium tuberculosis H37Rv and simultaneously treated with the competitive inhibitor NGmonomethyl-L-arginine (NGMMA). Mycobacterial intracellular replication was measured by 3H-uracil incorporation. NGMMA did not have any effect on mycobacterial replication. These results further suggest that human M phi do not produce NO- at least by the inducible pathway.

Biopterins↗
PubMedDate not supplied

[Prevalence of drug abuse in patients receiving care in adult emergency].

OBJECTIVE: To determine the association between patient admission due to trauma and the consumption of marihuana, cocaine and bazooka (basic cocaine paste) at the Central Hospital of Valencia, Venezuela. MATERIAL AND METHODS: 148 subjects were studied who had entered the emergency room due to lesions caused by aggression (AL), traffic accidents (TA), work-related accidents (WRA), self-inflicted injury (SII) and intoxication (INT). A questionnaire was applied and toxicology analyses performed. RESULTS: Drug consumption, alone or in combination, was found in 23.6% of individuals (13.5% cocaine, 7.4% marihuana and 2.7% both). Of the cocaine positive, 50% entered for AL, 20% for INT, 10% for SII, 5% for WRA and 15% for other causes. Of the marihuana positive, 36.4% entered for TA, followed by 27.3% for WRA, 18.18% for AL, 9.09% for INT and 9.09% for other causes. For combined drug consumption, entries for AL were 75% and for WRA, 25%. Alcohol consumption associated to cocaine was 50%, to marihuana, 9% and to combined drugs, 25%. CONCLUSIONS: These results show that one of every four hospital admissions for trauma is associated to drug abuse, alone or in combination. This reveals a close cause-effect relationship between the use of psychoactive drugs and trauma.

Accidents, Occupational↗
PubMedDate not supplied

Differences in extracellular matrix components and cell density during normal and dexamethasone-treated secondary palate development in two strains of mice with different susceptibility to glucocorticoid induced-clefting.

An histological and histochemical study analyzing cell density and distribution of extracellular matrix (ECM) components in two stages of developing secondary palate and in two strains of mice with different H-2 backgrounds was undertaken to investigate differences between a strain that is susceptible to glucocorticoid-induced cleft palate (A/Sn) and one that is resistant (C57/BL). In addition, the influence of dexamethasone treatment on ECM components was evaluated. A/Sn strain had significantly higher mesenchymal cell density compared to C57/BL at 13 days of gestation when the palatine processes are in vertical position. This difference in cell density was not significant at 14 days when palatal processes have been elevated. Dexamethasone did not alter cell density in both strains. A computer-assisted method utilizing image registration was used to compare the distribution of ECM components as judged by the stain intensity. Hyaluronate and collagen were higher in mesenchymal tissue of the palatine processes at 13 days of gestation in the C57/BL than in the A/ Sn strain. No differences in either hyaluronate or collagen were found in either strain and 14 days of development and dexamethasone treatment decreased these compounds in both strains. No differences were observed in laminin and type IV collagen of the basal lamina between strains in any of the stages studied. The results suggest that hyaluronic acid and collagen may be involved in different susceptibility to cortisone-induced cleft palate in the mouse.

Amino Acids, Diamino↗