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Biomedical subjects

M A Vidal

Publications and source records attributed to M A Vidal.

At least 19 recordsLinked to original sources
PubMed2005

[Hypovolemic shock during surgery caused by a rectus sheath hematoma].

Prophylactic treatment with low molecular weight heparins (LMWH) is currently widely used to prevent thromboembolic events. However, such treatment is not free of risk. Among the possible complications described is rectus sheath hematoma. We report the case of a patient undergoing surgery for a hypophysial adenoma approached by the transsphenoidal route. He received LMWH prophylaxis for thromboembolism and showed a tendency to hypotension during surgery. The patient's condition deteriorated to hypovolemic shock accompanied by episodes of atrial fibrillation with rapid ventricular response. With the transfusion of medications, blood products and plasma volume expanders, the patient was stabilized and surgery was completed. A computed tomography scan then revealed a hematoma occupying the greater part of the left anterior rectus muscle. With conservative wait-and-see treatment the abdominal symptoms disappeared and the hematoma gradually receded until fully resolved. Spontaneous rectus sheath hematoma is a rare condition. Presentation is quite nonspecific and computed tomography is needed for reaching a firm diagnosis. When a hematoma is large, the initial clinical picture may include hypovolemic shock, which may develop during surgery if the hematoma is not diagnosed early. Intraoperative management will be much more difficult than it would have been if diagnosis and treatment had taken place before the operation.

Adenoma↗
PubMed2004

Population dietary habits and physical activity modification with age.

OBJECTIVE: The aim of the present study was to analyse the relation between age and both dietary habits and leisure-time physical activity, and to determine nutrient inadequacy of aged groups in our population. DESIGN: Cross-sectional study. SETTING: A random sample of the 25-74-y-old population of Gerona, Spain. SUBJECTS: A total of 838 men and 910 women were selected from among the general population according to the 1991 census. OUTCOME MEASURES: Analysis of dietary habits, including amount and type of alcohol consumption, and detailed evaluation of leisure-time physical activity. RESULTS: Nutrient densities of carbohydrates, vitamin B(1), vitamin B(12), vitamin C, vitamin E, folate, potassium, iron, magnesium, copper, and dietary fiber increased significantly (P<0.05) with age in both genders, whereas an inverse trend was observed for total fat, saturated fatty acids, cholesterol, and sodium. Multiple linear regression analysis revealed a direct association of healthy dietary habits, characterized through a composite dietary score, with age after adjusting for several confounders both in men and women (P<0.001). This score was composed of folate, vitamin C, vitamin E, beta-carotene, dietary fibre, cholesterol, saturated fatty acids, and sodium. In all, 29 and 10% of male and female subjects aged 65-74 y, respectively, reported inadequate intakes of six or more of 16 nutrients. Total leisure-time physical activity increased with age in men (P<0.002), and was not different among female age groups. CONCLUSION: Dietary behaviours and levels of physical activity spent during leisure time indicate a healthy lifestyle of the aged men and women in the present population. Nutrient inadequacy observed in some aged men and women, however, deserves particular intervention of health-care programmes for this growing part of our society.

Adult↗
PubMed2004

[Sedation with remifentanil for tracheostomy in a pediatric patient].

Remifentanil is an ultra-short-acting opioid that is frequently used in adults for surgical anesthesia or conscious sedation, but its use in children is much less common. We report the case of a 7-year-old boy with lateral cervical tumors displacing all cervical and facial structures. An emergency tracheostomy was performed when he developed respiratory difficulty due to partial airway obstruction. Because of the size and location of the intraoral tumors and a history of bleeding, orotracheal intubation and other airway management techniques were ruled out. The tracheostomy was performed under local anesthesia and sedation with a perfusion of 0.05 x microgKg(-1) x min(-1) provided the necessary relaxation and immobility for surgery. Sedation under observation with monitoring is among the indications of remifentanil. Spontaneous breathing is maintained with infusions less than 0.05 to 0.1 microg x Kg(-1) x min(-1). In the case we report, the patient's risk of complete airway obstruction due to bleeding upon manipulation had to be assessed and compared with the respiratory depression that might possibly have been caused by remifentanil perfusion. We judged that the option of sedation would cause less morbidity and offered greater safety for the patient. The outcome of this case is consistent with reports that remifentanil is a good option for adequately sedating children who are breathing spontaneously.

Airway Obstruction↗
PubMed2003

Evidence for modulation of human epidermal differentiation and remodelling by CD40.

BACKGROUND: It is widely accepted that CD40 plays a critical role in the regulation of immune response. However, the significance of CD40 expression on normal human keratinocytes is only partially known. OBJECTIVES: To perform a morphological re-examination of the role of CD40 on the differentiation of human keratinocytes and remodelling of the epidermis. METHODS: Keratinocytes were grown on fibroblasts transfected with the CD40 ligand (CD40L) to investigate the formation of epidermal sheets in culture under the influence of the CD40L. Control experiments were carried out using the same cells but transfected with CD32. Further, three specific anti-CD40 monoclonal antibodies were used as soluble agonists to analyse the effect of CD40 ligation on keratinocyte differentiation. RESULTS: Epidermal sheets developing from keratinocytes cocultured with fibroblasts transfected with CD40L but not with CD32 showed an up to 50% reduction in thickness compared with control sheets. This change depended mostly on cellular flattening and a decrease in the number of cell layers, and was coincident with a transient decrease in cell surface CD40 immunoreactivity. On the other hand, normal epidermis, and freshly isolated and cultured keratinocytes revealed a predominant CD40+/Ki-67- phenotype that was demonstrated by double immunocytochemistry. Consistent with these observations, keratinocytes primed with interferon-gamma responded to the three soluble agonists, but not to control IgG1, producing immunoreactive (pro)filaggrin and displaying morphological changes in shape and size equivalent to those seen in differentiated cells. CONCLUSIONS: As a whole, our findings provide evidence that CD40+ keratinocytes represent a poorly differentiated population, not actively engaged in the cell cycle, which under specific stimulation is committed towards terminal differentiation.

Antibodies, Monoclonal↗
PubMed1997

Radial recession osteotomy for Kienböck's disease.

Sixty-eight patients underwent radial recession osteotomy for avascular necrosis of the lunate were retrospectively evaluated after an average follow-up period of 52 months. Twenty-five patients had undergone 1 or more additional procedures concurrently for treatment of Kienböck's disease. Pain diminished in 93% of patients, grip strength improved, and wrist motion was preserved; 75% of patients continued in their original occupations, including heavy labor. Surgical complications were uncommon. Four patients subsequently underwent salvage procedures, including 2 total wrist arthrodeses. Three of these 4 patients were receiving workers' compensation. One third of patients demonstrated lunate healing after joint leveling. Preliminary results suggest that concomitant lunate revascularization or vascularized bone grafting may improve the radiographic result. With rare exceptions, radial recession osteotomy relieves pain and improves function in Kienböck's disease.

Adolescent↗
PubMed1997

Trispiral tomographic staging of Kienböck's disease.

Trispiral tomography enhances the staging of Kienböck's disease and aids in surgical planning. The clinical records, plain x-rays, and trispiral tomograms of 105 patients with Kienböck's disease were reviewed. When tomograms were used, upward revision of the classification stage was indicated in 73% of patients with stage I or stage II disease and in 10% of those with stage III disease. On tomograms, 91% of patients had lunate fractures, compared with 55% on plain films. The most common lunate fracture seen on trispiral tomograms was a transverse shear fracture that represented lunate collapse; the next most common was a midcoronal fracture that may be displaced, causing fragment extrusion palmarly or dorsally. The most common instability pattern was nondissociative proximal row flexion, seen in stage III. Indices of carpal collapse and ulnar translation may be useful in following up patients, but values vary widely among patients.

Adolescent↗
PubMed1997

Development of a surface replacement arthroplasty for proximal interphalangeal joints.

Sixty-six surface replacement proximal interphalangeal prostheses with a CrCo proximal and an ultrahigh-molecular-weight polyethylene distal component were used in the hands of 47 patients (mean age, 58 years) over a 14-year period. There were 37 fingers with degenerative arthrosis, 16 with traumatic arthrosis, and 13 with rheumatoid arthritis. The mean follow-up period was 4.5 years (range, 1-14 years). The results based on pain relief, motion, and deformity were good in 32 fingers, fair in 19, and poor in 15. Poor results occurred primarily in fingers with previous extensive injury or static deformity. Results with a dorsal approach were better than those with a lateral or palmar approach. Component loosening at the bone-cement junction beyond a minimal radiolucent line was seen in one late x-ray. Results in individuals changed little after the first year of follow-up care, but results overall improved during the course of the study, perhaps because of improvements in surgical technique and experience.

Adolescent↗
PubMed1991

Cellular and subcellular distribution of 2,4-dinitrophenyl groups in mouse epidermis and regional lymph nodes after epicutaneous application of 2,4-dinitrofluorobenzene.

The cellular and subcellular distribution of 2,4-dinitrophenyl (DNP) groups in the epidermis and regional lymph nodes of the mouse was investigated after epicutaneous application of 2,4-dinitrofluorobenzene (DNFB) to sensitized and non-sensitized mice. The peroxidase-antiperoxidase method and the immunogold technique were used to visualize the DNP groups at both light and electron microscopic levels. The highest intensity of immunolabelling was found on tonofilaments of keratinocytes present in the upper layers of the epidermis. On the other hand, in vitro experiments showed that DNFB has the capacity to bind keratin which, together with immunocytochemistry, suggests that this molecule may be one of the skin protein carriers for DNFB. In addition, intense immunostaining for DNP was observed in the Golgi area of some epidermal Langerhans cells. Cells immunoreactive to DNP were also observed in the marginal sinus of cervical lymph nodes 6, 12 and 24 h after challenge. Immunoelectron microscopy revealed immunoreactive DNP groups in phagosomes of Langerhans cells at this site. The present findings support the hypothesis that the hapten DNFB penetrates passively into the cytoplasm of Langerhans cells, concentrates in the Golgi area and, during the migration of Langerhans cells to the lymph nodes, it is probably processed in the lysosomes before its presentation to T lymphocytes.

Animals↗
PubMed1991

Preiser's disease.

Nine patients with the diagnosis of unilateral Preiser's disease were seen between 1970 and 1987. The mean age of four male and five female patients was 37 years (range, 20 to 70 years). The diagnosis was based on radiographic evidence of sclerosis, fragmentation, erosion, and collapse of the proximal pole of the scaphoid. Onset was usually insidious but two had a preexisting radial hypoplasia, a third had a modest scaphoid malunion, and a fourth had a recent fall. Treatment consisted of scaphoid excision and silicone rubber prosthetic replacement in three, debridement of necrotic bone fragments in one, and different periods of cast support and observation in the remaining five. No relationship to ulnar variance was seen. Mean follow-up was 6.9 years. Of the scaphoid implants, two had subluxated, but only one was painful. In the more conservatively treated group, pain and function were only modestly limiting in four, who returned to their original occupations as did the one treated by curettage of necrotic bone in the proximal pole. One patient (case 4) was severely incapacitated because of associated severe congenital anomalies of the lower extremities. Polyaxial tomography permitted a better assessment of the degree of involvement and carpal alignment. Preiser's disease is a rare affliction of the carpal scaphoid which may involve the entire bone in avascular changes but primarily leads to fragmentation and collapse of the proximal pole. A conservative approach to treatment is favored based on this experience.

Adult↗
PubMed1990

A transgenic mouse model of sickle cell disorder.

A single base-pair mutation (beta s) in codon 6 of the human beta-globin gene, causing a single amino-acid substitution, is the cause of sickle cell anaemia. The mutant haemoglobin molecule, HbS, polymerizes when deoxygenated and causes deformation of the erythrocytes to a characteristic 'sickled' shape. Sickling of cells in small vessels causes painful crises and other life-threatening complications. Although the molecular basis for sickle cell anaemia has been known for 30 years, no definitive treatment is available. An animal model of sickle cell anaemia would not only allow a detailed analysis of the factors that initiate erythrocyte sickling in vivo and of the pathophysiology of the disease, but would also permit the development of novel approaches to the treatment of the disease. By using the dominant control region sequences from the human beta-globin locus, together with human alpha- and beta s-globin genes, we have obtained three transgenic mice with HbS levels ranging from 10 to 80% of total haemoglobin in their red cells. As observed in homozygous and heterozygous Hbs patients, the erythrocytes of this mouse sickle readily on deoxygenation. Irreversibly sickled cells, which are characteristic of sickle-cell patients homozygous for beta s, are also observed in the peripheral blood of the mouse with high levels of HbS.

Anemia, Sickle Cell↗
PubMed1989

Rapid detection of ultraviolet-induced reversion of an amber mutation in mouse L cells.

An amber codon (TAG) was introduced into the N-terminal coding region of the murine H-2Kb gene. The mutant gene was transfected into mouse L cells, and a clone containing a single unrearranged chromosomally integrated copy of the mutant gene was mutagenized with 254-nm UV radiation. Surviving cells were scored for surface expression of H-2Kb protein with in situ immunoperoxidase staining. Revertants were detected at a frequency of 3 X 10(-6) at a dose of 40 J/m2 (3-5% survival). Revertant genes, cloned by plasmid rescue, contained the expected thymine-to-cytosine transitions at the amber codon. These data show that revertants can be rapidly detected in mammalian cells without selection and provide a basis for the development of mammalian cell lines that could be used to study mutational phenomena. During this study the steady-state level of mRNA was reduced in L cells carrying the amber mutant H-2Kb gene compared with L cells containing a wild-type or revertant H-2Kb gene. This reduction was shown not to be due to transcriptional differences, suggesting that the amber mutation decreases stability of the H-2Kb mRNA.

Amino Acid Sequence↗
PubMed1985

Alternative mechanism of protein A-immunoglobulin interaction the VH-associated reactivity of a monoclonal human IgM.

The immunoglobulin site(s) that mediates the alternative mechanism of interaction between immunoglobulins and staphylococcal protein A (SpA) was studied by using a monoclonal human IgM. Several IgM fragments were tested for their inhibitory effect in a competitive binding assay of 125I-IgM to SpA. Only those fragments containing Fab mu pieces showed some inhibitory activity. The reactivity of the Fab mu region was retained in some of its subfragments, such as Fv or the VH domain, unlike isolated light chains or VL domains. Furthermore, antibodies specific for the VH domain completely inhibited the SpA-IgM interaction. These results indicate that the alternative SpA-binding site of IgM is located in VH regions.

Antibodies, Monoclonal↗
PubMed1984

Use of human IgM derived fragments to study structures responsible for protein A-reactivity.

The protein A-binding site of human IgM was studied by affinity chromatography on SpA-Sepharose using fragments derived from a human monoclonal SpA-reactive IgM, Iz. Neither Fabmu nor (Fc) 5mu fragments were retained on the column but IgM reactivity was unaffected by thermic treatment during proteolysis. Products intermediate between IgM and (Fc) 5mu fragments produced during shorter proteolysis showed a reactivity related to their content in Fabmu regions. On the other hand mild reduction of IgM Iz to monomeric subunits results in a dramatic loss of SpA-affinity. However these subunits, like F(ab') 2mu but unlike Fab'mu fragments, showed a significant interaction with the column. Thus, the principal requirement for SpA reactivity with IgM Iz seems to be related to the presence of Fabmu regions in a polymeric state resembling native IgM.

Antibodies, Monoclonal↗