PubMed Health⌕ Search

Biomedical subjects

J Montes

Publications and source records attributed to J Montes.

At least 19 recordsLinked to original sources
PubMed1998

Low-grade astrocytomas in children: evolving management strategies.

Developments in imaging and in neurosurgical techniques over the past decade have substantially altered the management of children with low-grade astrocytoma. Indications for surgery have become more clearly defined, and a larger proportion of children undergo complete or subtotal resection than in the past. Fewer receive adjuvant therapy, even though the options in this regard are more numerous now and theoretically likely to result in less morbidity than conventional external beam radiotherapy. This review will address in particular the correlations between location, imaging appearance, and behavior that need to be more widely appreciated, and present recommendations regarding the management of these tumors.

Astrocytoma↗
PubMed1998

[Memory T lymphocytes during infection and tuberculosis infection and disease].

OBJECTIVE: To examine the role of naive and memory T cells (as determined by CD45 isoforms) in recent tuberculosis infection and in pulmonary and pleural forms to the disease. To relate such subpopulations to serum levels of soluble IL-2 receptor (sIL-2R) and interleukin-6 (IL-6). METHODS: T cell subpopulations (CD3, CD4, CD8), naive (CD45RA), memory (CD45RO) and activated CD24+ T cells (IL-2 receptor) were measured in the peripheral blood and pleura of patients with recent tuberculosis infection (n = 7), pulmonary tuberculosis (n = 22) and tuberculosis pleurisy (n = 12). Serum levels of sIL-2 and IL-6 were determined in 13 patients with pleural or pulmonary tuberculosis and their relation to CD45RA and CD45RO subsets was analyzed. RESULTS: T lymphocytosis involving all the subpopulations studied, including naive and memory T cells, was detected, although the RA:RO ratio did not change in relation to control levels. Marked increases in memory T cells and CD24+ T cells were found for patients with tuberculous pleurisy. sIL-2 and IL-6 levels were unrelated to naive and memory T cell subpopulations. CONCLUSIONS: T lymphocytosis involving all T cell subsets can be observed in recent tuberculosis infection; both naive and memory T cells are implicated, although neither one predominates over the other. In tuberculous pleurisy there is compartmentalization of memory and activated T cells, which presumably play important roles in the local immune response to Mycobacterium tuberculosis.

Adolescent↗
PubMed1998

Hypothalamic hamartomas and gelastic epilepsy: a spectroscopic study.

BACKGROUND: Patients with hypothalamic hamartomas present with epileptic attacks of laughter and later experience multiple seizure types and cognitive decline, suggestive of secondary generalized epilepsy. It has been suggested in the past that gelastic seizures originate in the temporal lobes rather than in the hamartoma, but temporal resections have been ineffective. Recent electrophysiologic evidence suggests that the epileptogenic discharges may originate in the hamartoma itself. METHODS: We used proton magnetic resonance spectroscopic imaging to quantify the amount of neuronal damage in the temporal lobes and hamartomas of patients with hypothalamic hamartomas and gelastic seizures. Five patients were studied and the relative intensity of N-acetylaspartate to creatine (NAA/Cr) was determined for both temporal lobes as well as for the hamartoma. These values were compared with signals from the temporal lobes and hypothalami of normal control subjects. RESULTS: NAA/Cr was not significantly different from normal control subjects for either temporal lobe, nor was there a significant asymmetry between the two temporal lobes for any of the patients. NAA resonance signals were present in the hamartomas, and the ratio of NAA to Cr was decreased in the hamartomas compared with the hypothalami of normal control subjects (t = 4.5, p = 0.005). CONCLUSIONS: We found no detectable neuronal damage in the temporal lobes of patients with hypothalamic hamartomas and gelastic epilepsy. This is further evidence that gelastic seizures do not originate in the temporal lobes of these patients.

Adolescent↗
PubMed1997

Molecular cloning of TvDAO1, a gene encoding a D-amino acid oxidase from Trigonopsis variabilis and its expression in Saccharomyces cerevisiae and Kluyveromyces lactis.

The DAO1 gene of Trigonopsis variabilis encoding a D-amino acid oxidase (EC 1.4.3.3) was isolated from genomic clones selected for their specific hybridization to synthetic oligodeoxyribonucleotide probes based on regions of the enzyme that have been conserved through evolution. The nucleotide sequence of the gene predicts a protein with similarities to human, pig, rabbit, mouse and Fusarium solani D-amino acid oxidases. The open reading frame of the T. variabilis DAO1 gene was interrupted by an intron. The Dao1p sequence displays two regions, one in the N-terminal section--the FAD binding site--and the other near the C-terminal region that contains conserved signatures found in all the D-amino acid oxidases. The three C-terminal amino acids suggest that the enzyme may be located in peroxisomes. Northern blot experiments showed that no transcriptional activation occurred in the presence of D-methionine. The cDNA encoding Dao1p was expressed in Saccharomyces cerevisiae and Kluyveromyces lactis. Both yeast species are able to synthesize a functional enzyme under the control of the GAL1 promoter. In K. lactis, up to six times more enzyme units per gram of dry weight are produced with a multicopy plasmid in comparison with the wild-type strain of T. variabilis. The yeast expression system we describe may constitute an alternative source for the production of D-amino acid oxidases at industrial level.

Amino Acid Sequence↗
PubMed1996

Traumatic aneurysm from shaken baby syndrome: case report.

OBJECTIVE AND IMPORTANCE: We present a 6-week-old infant who developed a traumatic aneurysm from clearly documented shaken baby syndrome. Despite the theoretical similarity in the mechanism of such injuries, this is the first aneurysm reported that resulted from such a cause. The infant is also the youngest reported patient to have suffered from a traumatic aneurysm. CLINICAL PRESENTATION: Police records documented shaking of the child as well as direct impact on the child's head. Three weeks later, the patient developed an intracerebral hemorrhage, which was revealed by angiography to have resulted from a pericallosal artery aneurysm. TECHNIQUE: The aneurysm was totally resected through a porencephalic cyst, which had developed secondary to ischemic injury to the brain. CONCLUSION: The temporal course, as well as the location of this traumatic aneurysm, is similar to that in older patients.

Cerebral Angiography↗
PubMed1994

Stereotactic external beam irradiation in previously untreated brain tumors in children and adolescents.

Stereotactically guided external beam irradiation may be a useful form of treatment for small, well-circumscribed, but surgically inaccessible, primary brain tumors that are either benign or of low malignant potential. Between March 1988 and December 1991, 10 children and adolescents with previously untreated primary brain tumors were treated with stereotactic external beam irradiation (SEBI) using a linac-based dynamic technique. Eleven lesions were treated in the 10 patients. Treatment was given using a collimator diameter of 1.5-4 cm (median 2 cm). Single fractions of 18, 20, and 25 Gy were used for 3 lesions in 2 patients. A fractionated schedule delivering a median dose of 42 Gy in 6 fractions over 2 weeks was used in the remaining 8 patients. Morbidity related to treatment was minimal. Three patients suffered a temporary worsening of preexisting neurological symptoms and/or signs at 2, 5, and 5 months posttreatment, with subsequent recovery in all. With a median follow up post-SEBI of 17.5 months (range 5-47 months), improvement in neurological findings related to the lesion was noted for 5 treated lesions; 6 remained clinically stable. Seven of the 11 treated lesions improved radiologically, and only 2 showed evidence of progressive disease. Stereotactic external beam irradiation represents a potentially valuable therapeutic option for selected primary brain tumors in the pediatric and adolescent age group. Morbidity related to the treatment appears acceptable in frequency and type, and preliminary data with regard to response are encouraging. However, in order to assess the impact of such treatment on long-term tumor control and survival, further experience with a larger cohort of patients followed for a longer period of time will be necessary.

Adolescent↗
PubMed1992

Dysplastic gangliocytoma (Lhermitte-Duclos disease): CT and MR imaging.

Dysplastic gangliocytoma (Lhermitte-Duclos disease) is a rare entity. Usually presenting as a posterior fossa mass, dysplastic gangliocytoma is not a true neoplasm but a hard-to-characterize lesion that may represent an abnormality of cell migration or a phacomatosis. Previous reports of CT findings are rare in the radiologic literature, and high-field (1.5 Tesla) MR images have never been described in the pediatric age group. We present a case of dysplastic gangliocytoma in a one-year-old boy with CT and MR findings.

Cerebellar Neoplasms↗
PubMed1992

[Percutaneous mitral valvuloplasty. Immediate results with the 30 mm diameter dilatation balloon].

Percutaneous balloon dilatation of the mitral valve is a promising alternative to surgical treatment for patients with mitral stenosis. We analysed echocardiographic and haemodynamic results in 62 consecutive patients who underwent mitral dilatation with a big and one chamber balloon (30 mm diameter). The relationship between the dilatation balloon area and body surface was 4.2 (in 98% of patients it was bigger than 3.5). In the whole series we get significant improvements in the haemodynamic parameters and mitral areas (0.91 cm2 versus 1.78 cm2)(p < 0.005). According to the echocardiographic score, patients were divided in two groups. Good results (mitral area > 1.5 cm2, and final, valve area 50% greater than the initial area), were obtained in 93% of patients with a score of 8 or less, and in 45% of patients with a score bigger than 8. Seventy-five percent of patients with bad results (mitral area < 1.5 cm2) were in atrial fibrillation versus 37% of patients where we get a good results. Mortality of procedure was nulle, and two patients required surgery because of procedure failure for mitral insufficiency. We can conclude: percutaneous mitral valvuloplasty with single balloon is valid alternative, and good results can be expected if there is a good relationship between the area of balloon and patient's body-surface. The echocardiographic score and presence of atrial fibrillation can predict immediate results of this technique.

Adult↗
PubMed1991

[Fetal hemoglobin in children with different neoplasms].

The rate of HbF was studied in 123 children with different malignancies in order to assess its changes and relationship with other values of peripheral blood. The cases were distributed into 34 with acute lymphoblastic leukaemia (ALL), 19 with acute myelogenous leukaemia (AML), 23 cases of Hodgkin's disease (HD), 16 of non-Hodgkin lymphoma (NHL) and 31 of different solid tumors (ST). ALL and AML groups had the highest HbF rates (2.88 +/- 1.93% and 2.63 +/- 2.7%, respectively), followed by HD and NHL (1.89 +/- 1.09% and 1.81 +/- 1.68%, respectively), whereas the ST group showed the lowest values (1.32 +/- 1.74%). When comparing these figures with the findings in a group of adult leukaemia and lymphoma (1.6 +/- 0,7% and 1.2 +/- 0.5%, respectively), it was found that HbF was increased in the children to a higher extent. The analysis of the gamma G and gamma A chains of HbF, performed on 14 of the patients, showed in 7 cases a correlation similar to the newborn pattern, while this was similar to the adults in the remainders. These findings suggest that some factors intrinsic to the neoplasm might favour, in a different degree, the re-expression of HbF, which, in turn, would not necessarily mean a reversion to the foctal stages since the correlation of the gamma chains was similar to the adult pattern in 50% of the cases studied.

Adolescent↗