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Biomedical subjects

M J Esteban

Publications and source records attributed to M J Esteban.

12 recordsLinked to original sources
PubMed2001

Small-vessel vasculitis surrounding a spared temporal artery: clinical and pathological findings in a series of twenty-eight patients.

OBJECTIVE: Occasionally, a temporal artery biopsy reveals small-vessel vasculitis (SVV) surrounding a spared temporal artery, the significance of which is unclear. We analyzed the final diagnosis in a series of patients with this condition and tried to identify histopathologic features with potential usefulness in predicting the ultimate diagnosis. METHODS: We performed a clinical and histopathologic review of 28 patients in whom SVV surrounding a spared temporal artery was the first histologic finding that led to the diagnosis of vasculitis. For comparison purposes, we analyzed the pattern of small vessel involvement in 30 patients with biopsy-proven giant cell arteritis (GCA). RESULTS: GCA was considered the most likely diagnosis in 12 patients, based on the absence of clinical evidence of additional organ involvement and normal findings on muscle biopsy and electrophysiologic study. Three patients had systemic necrotizing vasculitis (SNV), based on the demonstration of typical lesions on subsequent muscle, nerve, or kidney biopsy. After extensive evaluation, 4 patients remained unclassifiable. Nine patients were incompletely studied. Fibrinoid necrosis was significantly more frequent in patients with SNV (P = 0.0022), whereas involvement of vasa vasorum was more frequent in patients classified as having GCA (P = 0.022). No differences in the pattern of small vessel involvement were found in patients with SVV surrounding a spared temporal artery who were classified as having GCA compared with patients with biopsy-proven GCA. Granulocytes were observed at similar frequency in all conditions. CONCLUSION: SVV may be the only abnormal feature in a temporal artery biopsy and the only histologic evidence of vasculitis. The diagnosis of GCA can be reasonably established in most of these patients when there is no apparent evidence of additional organ involvement. However, when fibrinoid necrosis is observed or the temporal artery vasa vasorum are not involved, SNV must be extensively excluded.

Adult↗
PubMed2000

Minimization methods for the one-particle dirac equation.

Taking into account relativistic effects in quantum chemistry is crucial for accurate computations involving heavy atoms. Standard numerical methods can deal with the problem of variational collapse and the appearance of spurious roots only in special cases. The goal of this Letter is to provide a general and robust method to compute particle bound states of the Dirac equation.

Journal Article↗
PubMed2000

[Prospective study of patients who leave the emergency department before being seen by the physician].

BACKGROUND: To define epidemiological characteristics, the main reasons, and outcome of patients who leave the emergency department (ED) without being seen by a physician. PATIENTS AND METHODS: We performed a prospective survey of patients who left the ED before medical visit over a period of 26 consecutive weeks. For every non-visited patient (NV), the next visited patient (V) was included as a control. Clinical and epidemiological data, reasons to leave ED and outcome were obtained from clinical records and personal telephone interview. RESULTS: Out of a total of 21,022 patients who were attended in the ED, 383 (1.8%) were NV. To be under 50-year-old, to come the ED alone, to be previously visited by a community physician, and to previous expect short waiting times for ED visit were associated with higher risk for being NV (p < 0.01, p < 0.01, p < 0.05 and p < 0.0001, respectively). The main reasons noted to leave the ED were: feeling better (35%), feeling too sick to wait longer (30%) and being too angry to wait (25%). Only 46% of the NV looked for medical care in the 72 following hours and 6.5% of them needing to be further to hospital. NV-patients considered as suffering a serious pathology at ED arrival, and those being visited by a community physician previously to go to ED were found to be at increased risk to be subsequently admitted (p = 0.01 and p = 0.001, respectively). CONCLUSIONS: Patients who leave ED department before being seen by a doctor are usually young, literate, have not previously visited their community physician, and consulted for minor complaints. The main reason to leave is their own impression of suffering a minor disease, and less than 50% visit another physician after their leaving, being the rate of hospital admission low. We should be particularly cautious with those patients referred by a community doctor and those identified as to have a seriously affected health status at their arrival at the hospital, since they are at increased risk to be admitted.

Age Factors↗
PubMed1998

[Acute abdomen: other initial symptom of abdominal lymphangioma].

Lymphangiomas are benign tumors, their growth are slow, customarily without symptoms, their location more frequent are in head or neck and they're diagnosed before the two first life years frequently. Their etiology continues uncertain, being accepted the congenital origin. We report on three cases of abdominal lymphangioma beginning as an acute abdomen. The importance of these cases is based mainly in the low frequency of presentation of these tumors in this location (2-5% of the lymphangiomas) and in their initial symptomatology.

Abdomen, Acute↗
PubMed1997

[Age-related changes in the cytolytic activity of aspartyl aminopeptidase in the cerebral cortex of the rat].

INTRODUCTION: Recently, neurotoxicity mediated by excitatory amino acids has been considered to be the etiopathogenic basis of various neurodegenerative processes, including aging of the brain. OBJECTIVE: Since the enzyme aspartyl-aminopeptidase (Asp-AP) may play a role in modifying the concentration of the cytotoxic amino acids glutamate and aspartate, we studied the changes in its activity in the rat cerebral cortex, which were possibly related to age. MATERIALS AND METHODS: Homogenates of frontal, parietal, temporal and occipital cortex were obtained from young and old rats. The activity of Asp-AP in these homogenates determined by fluorimetry. RESULTS: Our results showed a significant age-dependent drop in Asp-AP activity in the frontal, parietal and occipital cortices, with little change in the temporal cortex. CONCLUSIONS: These results may be understood as part of a general schedule of age-dependent modifications of the cerebral protease systems.

Aminopeptidases↗
PubMed1996

Desmoplastic supratentorial neuroepithelial tumours of childhood: imaging in 5 patients.

Desmoplastic neuroepithelial tumours are rare supratentorial neoplasms of infancy with a favourable prognosis. We characterised their imaging findings by reviewing the clinical and radiological reports of five affected children. The tumours were massive, predominantly cystic and with preferential frontal and parietal lobe involvement. The cystic component was in the white matter, with no communication with the ventricle. The solid part was superficially, abutting a meningeal surface, and showed intense contrast enhancement. A heterogeneous predominantly solid mass was observed in one patient. Thinning and deformation of the skull adjacent to the tumour was shown in four cases. Peritumoral oedema was absent or moderate. No calcification or haemorrhage were present. Angiography showed a tumour blush from the internal or external carotid arteries in one case each. Follow-up (3 months-9 years, mean 4.5 years) showed no recurrence.

Angiography↗
PubMed1996

[Treatment with Ethibloc of lymphangiomas and venous angiomas].

Lymphangioma and venous angioma are a group of pathological entities which have required surgical treatment since years. Extension, localization and poor delimitation of some lesions have resulted in technical difficulties and serious complications. Our group began the sclerosing therapy with an injection of fibrin adhesive and, due to the lack of response in the first patient, a program with Ethibloc as an alternative substance was developed. We present 10 cases, 4 lymphangiomas and 6 venous angiomas. In 50% of our patients one single session of sclerotherapy was made, in 25% two sessions, and in the rest 25% three. From 10 cases, 4 are still on treatment, complete remission in 5 cases, and good evolution in one case (mixed lymphangioma). As a long-term complication, we have noticed fistulization in 3 cases, and expulsion of the sclerosing agent. In our experience, percutaneous sclerosis with Ethibloc should be the first therapeutic alternative.

Adolescent↗
PubMed1995

Decrease in cytosolic Aspartyl-aminopeptidase but not in Alanyl-aminopeptidase activity in the frontal cortex of the aged rat.

To test the neurotoxic hypothesis of excitatory amino acids, we evaluated the possible contribution to the free acidic amino acid pool of Aspartyl-aminopeptidase activity in the frontal cortex of adult (3 month old) and aged rats (3 groups of animals aged 26, 29 and 33 months). Aspartyl-aminopeptidase activity showed a significant decrease in the oldest rats (29 and 33 months old) whereas the activity of Alanyl-aminopeptidase, an unspecific enzyme, did not change with age. These data invalidate the idea that excess free acidic amino acids are released by aminopeptidases in the aged rat but do provide evidence of age-related changes in this enzymatic activity. The possible implications of our findings for general alterations in protein degradation are discussed.

Aging↗
PubMed1995

Liver accessory lobe torsion in the infant.

A case of vomiting and selective epigastric pain secondary to volvulus of the pedicle of a liver accessory lobe, in an infant, is reported. Ultrasonic findings are useful and probably sufficient for a correct diagnosis.

Abdomen, Acute↗
PubMed1990

Influence of temperature on degradation kinetics of ceftriaxone in diluted and undiluted human serum.

The stability of ceftriaxone in undiluted human serum and in human serum diluted 1/20 in 0.1 M phosphate buffer (pH 6.0) was measured at -70, -40, -20, 4, and 37 degrees C. Ceftriaxone in diluted human serum contained at least 90% of the initial activity after 3 months of storage at -20, -40, and -70 degrees C; unbuffered human serum contained 82.41, 84.92, and 88.96% of the initial activity, respectively. Ceftriaxone in unbuffered human serum and in diluted human serum showed 80.33 and 86.25% of the initial activity, respectively, after 55 days at 4 degrees C. After 120 h at 37 degrees C, this antibiotic in unbuffered human serum contained 33.08% of the initial activity, whereas samples of diluted human serum contained more than 60%. Consequently, the stability of antibiotic in human serum diluted 1/20 in 0.1 M phosphate buffer (pH 6.0) is increased.

Buffers↗