Biomedical subjects

J Vaquero

Publications and source records attributed to J Vaquero.

At least 37 records · Page 2Linked to original sources

PubMed2001

Prognostic significance of the endothelial surface in low-grade resected oligodendrogliomas.

The importance of angiogenesis as a prognostic factor in brain tumours has recently been reported. In this study, we analysed the long-term prognostic significance of a morphometric score expressing the endothelial area for every 1000 tumour cells, in tumour tissue from 26 patients with a low-grade oligodendroglioma that has been treated surgically and irradiated, and has a MIB-1 labelling index (MIB-1 LI) of less than 1%. In each tumour, a vascular endothelial surface index (VESI) was determined as the CD-34 immunostained endothelial area in micron 2 per 1000 tumour cells. Patients with a VESI of less than 15 (n = 12) showed a survival at 5 and 10 years of 100 and 71%, respectively, versus a survival of 50 and 0% for patients presenting a VESI greater than 15 (n = 14); p < 0.05). Our present findings suggest the usefulness of VESI as a long-term prognostic pathological factor in low-grade oligodendroglioma.

Adolescent↗

PubMed2001

Presence and significance of CD-95 (Fas/APO1) expression after spinal cord injury.

OBJECT: A glycoprotein, CD95 (Fas/APO1) is widely considered to be implicated in the development of apoptosis in a number of tissues. Based on the hypothesis that apoptosis is related to cell death after spinal cord injury (SCI), the authors studied the presence and distribution of CD95 (Fas/APO1)-positive cells in injured spinal cord tissue for the purpose of determining the significance of this protein during the early phases of SCI. METHODS: The presence and distribution of cells showing positive immunostaining for CD95 (Fas/APO1) were studied 1, 4, 8, 24, 48, and 72 hours and 1, 2, and 4 weeks after induction of experimental SCI in rats. Studies were conducted using a monoclonal antibody to the CD95 (Fas/APO1) protein. Positivity for CD95 (Fas/APO1) was observed in apoptotic cells, mainly in the gray matter, 1 hour after trauma, and the number of immunostained cells increased for the first 8 hours, at which time the protein was expressed in both gray and white matter. From 24 to 72 hours postinjury, the number of immunostained cells decreased in the gray matter, but increased in the white matter. From then on, there were fewer CD95 (Fas/APO1)-positive cells, but some cells in the white matter still exhibited positive immunostaining 1 and 2 weeks after injury. At 4 weeks, there remained no CD95 (Fas/APO1)-positive cells in injured spinal cord. CONCLUSIONS: These findings indicate that CD95 (Fas/APO1) is expressed after SCI, suggesting a role for this protein in the development of apoptosis after trauma and the possibility of a new therapeutic approach to SCI based on blocking the CD95 (Fas/APO1) system.

Animals↗

PubMed2001

Absence of mutation of the p73 gene in astrocytic neoplasms.

In subgroups of astrocytic neoplasms, including glioblastoma (GBM), mutations of the p53 tumour suppressor gene lead to loss of growth-suppressive properties. A p53-related gene termed p73 has recently been identified; its gene product shows structural and functional similarities to p53. After being mapped to chromosome region 1p36, p73 was proposed to act as a tumour suppressor gene, as this region is frequently deleted in a variety of human cancers, including astrocytic tumours. To determine whether p73 is involved in astrocytoma/GBM development, we analysed 10 pilocytic astrocytomas, 15 WHO grade II astrocytomas, 15 WHO grade III anaplastic astrocytomas, and 20 GBM for p73 gene alterations. In parallel, we used six polymorphic markers to determine the allelic status of region 1p36 in this tumour series. Although loss of heterozygosity was evidenced in 12 of 60 cases (20% of samples), PCR-SSCP and direct sequencing failed to detect any gene mutation in the entire coding region and intronic sequences of p73. Eight tumours displayed five distinct polymorphic nucleotide changes, also present in the corresponding normal DNA. These variations consisted of T-->C variation, with no change in Thr173; C-->T transition, with no change in His197; exon 9 simultaneous double change C-->T and T-->C , with no variations in Ala336 and His349, respectively, and C-->T change at exon 9/-24 position of intron 8. These results suggest that, in astrocytic gliomas, p73 may not play a major role as a tumour suppressor, but the relatively high incidence of LOH confirms the presence at 1p36 of an as yet unidentified gene of this category, with a key function in astrocytoma/GBM progression.

Astrocytoma↗

PubMed2000

High-resolution analysis of chromosome arm 1p alterations in meningioma.

Loss of heterozygosity (LOH) for loci on chromosome arm 1p is a relatively common event in human meningioma, and this anomaly has been proposed to be associated with the development of grade II or grade III forms (atypical and anaplastic meningiomas). Nevertheless, the limited data available do not allow the establishment of the frequency and the extent of the affected 1p regions. To determine the status of chromosome 1p in meningiomas, we have performed a comprehensive analysis of LOH on 1p in 100 meningiomas using a high density of 1p-marker loci. Allelic loss was found in 35% of tumors, most corresponding to nontypical meningiomas that also displayed losses for loci on chromosome 22. Although some tumors displayed complex rearrangements leading to distinct 1p deletions, the patterns of loss indicated two main target regions: 1p36 and 1p34-p32, which represent the most frequently involved regions, whereas 1p22 and 1p21.1-1p13 regions appeared deleted in some tumors. These results suggest that there may be several putative tumor suppressor genes on 1p, the inactivation of which may be important in the pathogenesis of meningiomas, as well as in other tumor types.

Brain Neoplasms↗

PubMed2000

hRAD54 gene and 1p high-resolution deletion-mapping analyses in oligodendrogliomas.

The hRAD54 protein belongs to a superfamily of DNA helicases, and mutations in genes with DNA helicase function have been found to be responsible for cancer-prone syndromes (xeroderma pigmentosum, Bloom syndrome, Werner syndrome). hRAD54 thus could be a candidate modifier gene in tumors characterized by allelic imbalance at 1p32, the chromosome region in which this gene is located. Using a panel of 38 1p and five 1q markers, we therefore performed deletion-mapping analysis on a series of 35 oligodendrogliomas, which were also studied for mutations in the hRAD54 gene. Deletions of the short arm of chromosome 1 were evidenced in 26 tumors, mostly involving 1p36-1p13; all thus displayed loss of the 1p32 region. We used PCR/SSCP to examine all 18 exons of the hRAD54 gene for mutations in 25 tumors, but the mobility shifts detected corresponded to previously identified polymorphic changes: T-to-C transition at nucleotide 2865 (with no amino acid change) and at nucleotide 3008, at the 3' untranslated region. We conclude that hRAD54 gene alterations are not required for malignant transformation of oligodendrogliomas.

Chromosome Deletion↗

PubMed2000

Stereotactic biopsy for brain tumors: is it always necessary?

BACKGROUND: Stereotactic biopsy is currently being used in oncological neurosurgery despite its limitations. The purpose of this study is to compare its diagnostic reliability with that of the diagnosis based on clinical data and neuroimaging techniques. METHODS: We studied 200 patients (134 men and 66 women) who underwent 212 stereotactic biopsy procedures to assess brain tumors. All were subjected to CT scan and 71 patients also underwent MRI. A presumptive diagnosis of brain tumor was established in each case and the findings compared with the results of stereotactic biopsy and the clinical course. RESULTS: A clear presumptive diagnosis was established before stereotactic biopsy in 90% of the patients, and in 95% of this group, the diagnosis was confirmed by the biopsy and/or the clinical course. The stereotactic biopsy modified the presumptive diagnosis in eight patients (4%), without changing the clinical diagnosis of malignant lesion. In our present series, 10% of the procedures were of no help in determining a diagnosis and in 7% of patients, the stereotactic biopsy led to diagnostic errors that influenced the therapeutic management and resulted in an erroneous prognosis. CONCLUSIONS: These data confirm the need for clinical correlation with the findings obtained at stereotactic biopsy and suggest that stereotactic biopsy may not always be useful or necessary in the management of brain tumor patients. According to our present critical analysis, when a clear presumptive diagnosis of brain tumor can be made, it may be sufficient to base the management of the patient only on clinical and neuroimaging findings.

Adult↗

PubMed2000

Grafting of neural tissue in chronically injured spinal cord: influence of the donor tissue on regenerative activity.

BACKGROUND: To determine the influence of different nervous tissue grafts on the regenerative activity of chronically injured spinal cord, an experimental study examining the expression of the proliferating cell nuclear antigen (PCNA) in chronically injured spinal cord subjected to neural grafting was performed. METHODS: Three months after induced spinal cord injury, paraplegic Wistar rats were subjected to grafting of neural tissue. Grafts consisted of fetal brain cortex, fetal spinal cord, crushed adult peripheral nerve tissue, or fetal brain cortex combined with crushed adult peripheral nerve tissue. Four months later, the spinal cord was removed and the grafted zone was studied by means of immunohistochemical demonstration of PCNA. RESULTS: Different patterns of PCNA expression were recorded in the different experimental groups. PCNA-immunostained cells in injured spinal cord tissue, mainly ependymal cells and astrocytes, increased when co-transplantation of fetal brain cortex and crushed adult peripheral nerve tissue was used, in comparison to other neural donor tissues. In the grafted tissue, proliferative activity was greater when fetal brain cortex, alone or with peripheral nerve, was used, in comparison to the use of fetal spinal cord or adult peripheral nerve tissue. Nevertheless, the number of PCNA-positive cells does not seem to be influenced by the presence of peripheral nerve tissue in the donor tissue. CONCLUSIONS: Our present findings suggest the effectiveness of co-transplantation of peripheral nerve tissue and fetal brain tissue in attempts at spinal cord reconstruction after injury.

Animals↗

PubMed2000

Prognostic significance of clinical and angiogenesis-related factors in low-grade oligodendrogliomas.

BACKGROUND: Keeping in mind that oligodendrogliomas have unpredictable biological behavior, the aim of this study is to investigate the prognostic significance of VEGF expression and microvessel density in a homogeneous series of low-grade oligodendrogliomas. METHODS: For this study 36 patients with a low-grade oligodendroglioma treated by surgical resection and radiotherapy were selected. At the time of surgery, in all cases the Karnofsky Performance Scale (KPS) score was more than 70, and the study of the resected tumor disclosed a Ki-67/MIB-1 labeling index (MBI-1 LI) less than 1%. In this homogeneous series, immunohistochemical studies were performed using monoclonal antibodies against VEGF in order to study the expression of this cytokine, and against vascular endothelial CD-34 antigen, in order to identify microvessels. RESULTS: Our results show that in contrast to low-grade astrocytomas, low-grade oligodendrogliomas lacked immunoreactive VEGF. Oligodendrogliomas with low vascular density (less than 20 microvessels per microscopical field, at 200 x) or high vascular density (more than 100 microvessels per field, at 200 x) were identified, but this factor had no influence on the survival rate of patients. On the other hand, analysis of the present series showed that clinical factors, such as age or extent of surgical resection, were not significantly associated with survival. CONCLUSIONS: In contrast to low-grade astrocytomas, the angiogenesis score of low-grade oligodendrogliomas (counting the number of microvessels in tumor tissue) adds little information to help predict tumor behavior.

Antigens, CD34↗

PubMed2000

Prognostic significance of endothelial surface score and MIB-1 labeling index in glioblastoma.

The aim of this study is to investigate the usefulness of a vascular endothelial surface score (VESS) and MIB-1 labeling index (MIB-1 LI), in a defined series of glioblastomas, as biological markers with prognostic significance of survival. Tumor tissue and survival were studied in a series of 38 patients with glioblastoma, previously treated by surgical resection and radiotherapy. For each tumor, immunohistochemical and morphometric studies were performed in order to study MIB-1 LI, and VESS, expressed as the CD-34 immunostained endothelial surface per 1000 tumor cells. The survival for the entire patient population of the series was 48.1+/-14.1 weeks, and the mean VESS for the tumors of the series ranged from 16.7 to 107 microm2 per 1000 tumor cells (mean: 38.7+/-18.2). Factors such as age or MIB-1 LI were not significatively associated with survival, but the median survival for the 18 patients with a VESS less than 35 was 50.7+/-3.7 weeks, versus 45.9+/-2.8 weeks for the 20 patients showing a VESS higher than 36 (p < 0.05). Our present results suggest that tumor VESS, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells, may have usefulness, as angiogenic-related factor influencing survival, in patients with glioblastoma.

Adult↗

PubMed2000

Expression of vascular permeability factor in glioblastoma specimens: correlation with tumor vascular endothelial surface and peritumoral edema.

Keeping in mind that the expression of vascular permeability factor (VPF) in astrocytic tumors has been related to tumor angiogenesis and peritumoral edema (PE), the aim of this study is to investigate the correlation between degree of VPF expression by tumor cells, and degree of PE and vascular endothelial surface (VES) in glioblastoma. Tumor tissue and neuroimaging data were studied in a series of 38 patients with glioblastoma. For each tumor, immunohistochemical and morphometric studies were performed in order to obtain a score of VPF expression, and a VES score, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells. These parameters were related to the degree of PE. The results show that in glioblastomas there exist a clear correlation between the tumor-cell expression of VPF and VES, but we failed to obtain a significant correlation between degree of PE and degree of VES, or between degree of VPF expression and degree of PE. Our present results suggest that in glioblastomas, tumor angiogenesis is clearly related to the expression of VPF by tumor cells, but factors other than intratumoralpresence of VPF may contribute to the development of PE.

Adult↗

PubMed2000

Endoscopic fenestration of a symptomatic cyst of the septum pellucidum.

We present the case of a 25-year-old woman suffering from chronic severe headaches and syncope associated with an expanding cyst of the septum pellucidum. After a simple endoscopic fenestration of the cyst the symptoms resolved, resulting in an excellent clinical outcome. This case shows that simple endoscopic fenestration may produce a rapid and maintained symptomatic improvement in patients with an expanding cyst of the septum pellucidum.

Adult↗

PubMed2000

Cerebral angiofibroma: case report.

OBJECTIVE AND IMPORTANCE: Intracranial fibromatous tumors are very rare lesions, with few reported cases. CLINICAL PRESENTATION: We report the case of a 34-year-old male patient who experienced seizures resulting from a cystic lesion in the left occipital region, which remained unchanged for 11 years. After the seizures increased in number, magnetic resonance imaging revealed a large cyst with a tumor nodule. INTERVENTION: A left occipital craniotomy was performed, and the tumor was removed. Pathological studies, including immunohistochemical and ultrastructural analyses, indicated that this neoplasm was composed of fibrous and angiomatous components, and a diagnosis of cerebral angiofibroma was established. CONCLUSION: Cerebral and meningeal fibromas are rare neoplasms that differ from solitary fibrous tumors and fibrous meningiomas. When a number of prominent blood vessels are present in a cerebral or meningeal fibroma, a diagnosis of angiofibroma can be considered. It is possible that some nodular brain tumors that were previously described as meningioangiomatosis could be reclassified as cerebral or meningeal angiofibromas.

Adult↗

PubMed2000

[Esophageal fibrovascular polyp: report of 2 cases].

Fibrovascular esophageal polyps are benign intraluminal tumors that, although of slow growth, may become large. We describe the features of two cases, diagnosed in our department, and emphasize the endoscopic aspects of the lesion.

Aged↗

PubMed1999

NF2 gene mutations and allelic status of 1p, 14q and 22q in sporadic meningiomas.

Formation of meningiomas and their progression to malignancy may be a multi-step process, implying accumulation of genetic mutations at specific loci. To determine the relationship between early NF2 gene inactivation and the molecular mechanisms that may contribute to meningioma tumor progression, we have performed deletion mapping analysis at chromosomes 1, 14 and 22 in a series of 81 sporadic meningiomas (54 grade I (typical), 25 grade II (atypical) and two grade III (anaplastic)), which were also studied for NF2 gene mutations. Single-strand conformational polymorphism analysis was used to identify 11 mutations in five of the eight exons of the NF2 gene studied. All 11 tumors displayed loss of heterozygosity (LOH) for chromosome 22 markers; this anomaly was also detected in 33 additional tumors. Twenty-nine and 23 cases were characterized by LOH at 1p and 14q, respectively, mostly corresponding to aggressive tumors that also generally displayed LOH 22. All three alterations were detected in association in seven grade II and two grade III meningiomas, corroborating the hypothesis that the formation of aggressive meningiomas follows a multi-step tumor progression model.

Adolescent↗

PubMed1999

Search for mutations of the hRAD54 gene in sporadic meningiomas with deletion at 1p32.

The hRAD54 gene is related to a family of genes involved in DNA recombination and repair and encodes a protein with DNA helicase activity. hRAD54 has been mapped to 1p32, a region frequently involved in deletions in a variety of tumor types, including atypical and anaplastic meningiomas. To determine whether alterations of hRAD54 are a common event in meningeal tumors, by means of polymerase chain reaction-single-stranded conformation analysis we examined 29 tumor samples characterized by 1p deletions for hRAD54 mutations. Although 18 tumors displayed allelic loss at the gene region (1p32) as determined by microsatellite marker analysis, the sole coding-sequence alteration detected corresponded to a T-->C transition, with no amino-acid change. The genotype distribution was 10.34% TT, 44.8% TC, and 44.8% CC, whereas in the normal controls it was 3.77% TT, 13.2% TC, and 83.01% CC, and most meningiomas with 1 p32 deletion retained allele C. Another polymorphism due to a T-->C change was evidenced at nt 3008, in the 3' untranslated region. This change was evidenced in all cases we sequenced. These results appear to exclude the involvement of the hRAD54 gene in the pathogenesis of the nontypical meningiomas, although a detrimental effect of the hRAD54 polymorphisms cannot be ruled out.

3' Untranslated Regions↗

PubMed1999

Vascular permeability factor expression in cerebellar hemangioblastomas: correlation with tumor-associated cysts.

The presence of vascular endothelial growth/permeability factor (VEG/PF) has been studied in histological specimens from a series of 16 cerebellar hemangioblastomas. In this series, the tumors were classified as presenting a macroscopic solid pattern (4 cases), a mainly solid pattern with macroscopic cysts (4 cases) or a mainly cystic pattern (8 cases). Solid tumors showed a low degree (75% of cases) or moderate degree (25% of cases) of VEG/PF positivity. The mainly solid tumors containing macroscopic cysts showed a moderate degree (50% of cases) or high degree (50% of cases) of VEG/PF positivity. Nevertheless, mainly cystic hemangioblastomas showed a high degree (87.5% of cases) or moderate degree (12.5% of cases) of VEG/PF positivity. These findings suggest that the predominance of a cystic or solid macroscopic appearance of cerebellar hemangioblastomas may be influenced by the degree of VEG/PF expression within the tumor tissue.

Cerebellar Neoplasms↗

PubMed1999

Expression of vascular permeability factor in craniopharyngioma.

OBJECT: The expression of vascular endothelial growth/permeability factor (VEG/PF) has recently been correlated with the presence of tumor-associated cysts in some intracranial tumors. The purpose of this study was to evaluate a possible relationship between the presence of VEG/PF and the formation of cysts in craniopharyngiomas. METHODS: The expression of VEG/PF was studied in histological specimens from a series of 12 craniopharyngiomas. In this series, the tumors were classified as presenting a mainly solid pattern with small macroscopic cysts (four patients) or a mainly cystic pattern (eight patients). The mainly solid tumors containing small macroscopic cysts showed little or no VEG/PF positivity, which was mainly present in tumor cells surrounding cysts. Nevertheless, mainly cystic craniopharyngiomas showed a moderate or high degree of VEG/PF positivity in tumor cells. CONCLUSIONS: These findings indicate that the predominance of a cystic or solid macroscopic appearance of craniopharyngiomas may be influenced by the degree of VEG/PF expression within the tumor cells.

Adult↗

PubMed1999

Vascular endothelial growth/permeability factor in spinal cord injury.

OBJECT: Predicated on the hypothesis that this cytokine can contribute to the development of vascular hyperpermeability, leading to tissue edema after trauma, the purpose of this study was to determine the presence in tissue of vascular endothelial growth/permeability factor (VEG/PF) after experimental spinal cord injury. METHODS: The presence of VEG/PF was studied at 8 hours and 2, 8, and 14 days after a traumatic injury in adult Wistar rats. Studies were conducted in which a monoclonal antibody to the VEG/PF was used. Strong VEG/PF immunoreactivity was detected in the walls of pial and intramedullary vessels and in reactive astrocytes 8 hours posttrauma and was unchanged on Days 2 and 8. By Day 14, immunoreactivity decreased, and most of the arterioles from the pia and gray matter showed no mural VEG/PF. CONCLUSIONS: The authors' present findings suggest a role for this cytokine in the development of tissue edema after spinal cord trauma and point to the possible usefulness of a therapeutic approach to spinal cord injury based on blocking the cell expression of VEG/PF or its physiological effects.

Animals↗