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Biomedical subjects

M G Blázquez

Publications and source records attributed to M G Blázquez.

At least 19 recordsLinked to original sources
PubMed1997

Gene therapy in brain tumours: implications of the size of glioblastoma on its curability.

The authors have used the thymidine kinase/ganciclovir system to block glioblastoma multiforme neoplastic cells in vivo, both in experimental animals and in two patients in which the more conventional therapies had been unsuccessful. In the Wistar rat it was found that the curability potential of the system is correlated with tumoral volume. Tumours smaller than 20 mm3 can be cured with defective retrovirus that do not carry the Herpes simplex thymidine kinase (Hsvtk) gene. While tumours smaller than 150 mm3 can regress totally by the kinase/ganciclovir system, those above that size cannot be cured by this treatment. In humans the situation seems very similar in that the authors have been unable either to reduce the tumour size of recurrent patients with tumour volumes larger than 100 cm2 applying the standard thymidine kinase/ganciclovir gene therapy or to prolong their survival time more than 8 months [7]. When a combination of size reduction by neurosurgery and gene therapy was used the survival time increased considerably. Two patients have been treated by partial surgery and repeated treatment with thymidine kinase/ganciclovir through an Ommaya reservoir connected to a catheter leading into the tumour cavity. The magnetic resonance imaging (MRI) of these patients show only a residual tumoral growth along side the tumoral bed. The procedure may be partially controlling the proliferation of cancerous cells, because, these two patients having recurrent glioblastoma, are alive 11 and 17 months after the beginning of the treatment.

Animals↗
PubMed1996

Human malignant brain tumor response to herpes simplex thymidine kinase (HSVtk)/ganciclovir gene therapy.

Growing cells from human brain tumors have been treated in vitro and in vivo with murine therapeutic retroviral producer cells. The therapeutic retrovirus carried the potential suicide gene thymidine kinase (tk) from the herpes simplex virus (HSV). After a few days, in which a large proportion of the tumoral cells had the opportunity to acquire a copy of the retrovirus, treatment with ganciclovir was initiated and considered responsible for considerable cell death both in vitro and in vivo. The in vivo experiments were performed in five adult patients who had failed standard therapy and were expected to survive only a few weeks.

3T3 Cells↗
PubMed1996

[Iatrogenic spinal epidermoid tumors. A late complication of spinal puncture].

INTRODUCTION. Epidermoid tumors in the spinal canal are rare. Whether congenitally or iatrogenically caused, they form as the result of epidermal cells implanted within the spinal channel. Such implantation can occur during a variety of procedures and events such as bullet wounds, surgery, myelography or punctures for diagnosis, anesthesia or treatment. Although this complication is not discussed in books or journals on anesthesiology, we have found it mentioned in over 100 published cases reporting iatrogenically caused spinal epidermoid tumors. ETIOPATHOGENESIS. Iatrogenic epidermoid tumors of the spine derive from the implantation of epidermal tissue transported inside the spinal canal during lumbar punctures without guidance or with inadequate guidance. There is ample evidence that such tumors are iatrogenic. All cases occur in patients with a history of lumbar puncture. They are rarely associated with congenital anomalies. They are extramedullary. They tend to develop near sites of earlier lumbar puncture, usually near the conus medullaris and the cauda equina. Iatrogenic epidermoid tumors of the spine have been reproduced experimentally in two studies in which autologous skin fragments were implanted in the spinal canal. CLINICAL SIGNS. These tumors are well tolerated by patients for extended periods of time, ranging from 2 to 10 years. At the cauda equinus, tumors can grow slowly for long periods without signs of nerve compression. Symptoms are directly related to tumor size and site. All patients with tumors at the cauda equinus report severe pain radiating toward the roots of compressed nerves. Nuclear magnetic resonance makes it possible to detect the tumor without administration of intrathecal contrast. At present gadolinium-DTPA improves the image so that these tumors can be distinguished from other types. The prognosis for epidermoid tumors of the spine is good, as they are histologically benign. Treatment is always surgical. CONCLUSION. Although the causal relation between epidermoid spinal tumors and lumbar puncture is well documented, anesthesiologists are not sufficiently aware of this possible complication. Between 1977 and 1995, 28 new cases were published. We believe that a deeper understanding of such rare complications will show us how to prevent them while providing appropriate use of epidural and subarachnoid anesthesia.

Epidermal Cyst↗
PubMed1993

Timing of p53 mutations during astrocytoma tumorigenesis.

Using a combination of polymerase chain reaction and single-strand conformation polymorphism techniques (PCR-SSCP) we have analyzed 78 brain tumor samples (70 primary and 8 metastatic) for the presence of mutations in the conserved regions of the Tp53 (tumor p53) gene. We have found that only two groups, gliomas (exclusively in astrocytomas) and metastases, displayed Tp53 mutations. Three of eight (37.5%) metastases showed a mutant Tp53 allele accompanied by loss of the normal one. In contrast, the frequency of Tp53 mutations in the primary brain tumors examined was lower (5.7%). Although we have examined different types of primary brain tumors, Tp53 mutations were exclusively observed in both, low and high-grade astrocytomas (four of 24). The Tp53 mutations detected in astrocytic tumors appear to be correlated with the malignancy grade. The low-grade astrocytomas were heterozygous for the mutation, whereas the high-grade astrocytomas had affected the two Tp53 alleles, suggesting a two-steps model for inactivation of the p53 gene in astrocytomas. Thus, single p53 mutation seems to occur in initial stages of astrocytoma tumorigenesis; the later lost of the remaining wild-type allele appears associated with the progression towards a more malignant stage.

Adenocarcinoma↗
PubMed1990

Unusual CT image of a cerebral hydatid cyst.

We report an unusual case of cerebral hydatid cyst which was found with CT. Unenhanced CT showed a hyperdense, not calcified, ring surrounding the cyst cavity. This has never been reported before. We propose a possible explanation for such abnormal behaviour.

Brain↗
PubMed1990

Thalamic cavernous malformation. Case report.

A 50-year-old man with a right hemiparesis was found to have a cavernous malformation in the left thalamus. The diagnosis was made using magnetic resonance (MR) imaging. The vascular malformation was totally removed by means of a transcallosal interhemispheric surgical approach, but the patient's neurological deficit worsened. The role of MR imaging in establishing the diagnosis is emphasized and other published cases with thalamic locations are reviewed.

Aphasia, Broca↗
PubMed1989

Management of cerebral mass effect lesions in multiple sclerosis.

We present three cases of multiple sclerosis (MS) with tumoural manifestation during the disease in two cases, and as the first symptom in one case. Surgery is the first option, when a new patient presents with clinical features suggestive of a brain tumour. When an MS patient presents with these symptoms, corticoid treatment should be initiated and only if mass effect in computerized tomography (CT) persists, should surgery be considered.

Adult↗
PubMed1989

Intracranial cavernous angioma in the dura.

Cavernous malformations located in the dura are rare. We present a case of a large cavernous malformation located in the anterior fossa and implanted in the dura of a pregnant woman. It showed great vascularization on an angiogram, and resembled a meningioma on computed tomographic scan. The operation was difficult because of the tumor's great vascularity and profuse bleeding.

Adult↗
PubMed1988

Intradural herniated dorsal disc: case report and review of the literature.

A 67-year-old man with a 1 1/2-month history of spastic paraparesis caused by a dorsal intradural disc herniation underwent surgical treatment via a posterior approach. Dorsal herniated discs are rare, and intradural dorsal disc herniations are even more infrequent. Including this case, the medical literature reviewed describes only four such cases.

Aged↗
PubMed1988

Intraventricular varix causing hemorrhage. Case report.

A case of a cerebrovascular varix located in the right lateral ventricle is reported. The patient suffered intraventricular and subarachnoid hemorrhages. The intraventricular varix was coagulated and excised.

Cerebral Angiography↗
PubMed1987

Malignant and atypical meningiomas: a reappraisal of clinical, histological, and computed tomographic features.

A series of 21 patients with atypical and malignant meningiomas is presented. Histological criteria such as high cellularity, typical and atypical mitosis, necrosis, infiltration of the underlying brain, poor differentiation, and distant metastasis define nonbenign meningiomas. Male predominance in this nonbenign group is significant when compared to a group of 205 benign meningiomas, which were also operated on. The malignant and atypical meningiomas are compared with the benign meningiomas, and special emphasis is placed on their computed tomographic features. The presence of tumor fringes (suggesting invasion of the brain substance) and intratumoral hypodense areas were both significant signs of malignancy of atypia. Radical surgical excision is still considered the treatment of choice.

Adolescent↗
PubMed1987

Neuroepithelial cyst in the optic nerve. Case report.

A 34-year-old woman presented with progressive loss of vision in her left eye of 2 months' evolution. Computerized tomography showed a hypodense lesion in the suprasellar region. At surgery a cystic lesion was found inside the optic nerve. Histological study proved it to be a neuroepithelial cyst. The pathogenesis of a neuroepithelial cyst in such an exceptional site is discussed.

Adult↗
PubMed1983

Posterior fossa epidural hematomas: a review and synthesis.

The authors report three patients with posterior fossa epidural hematomas and analyze 80 additional cases in the accessible literature. They occur in the younger age groups with a clear male predominance (3.6 to 1). The loss of consciousness at the time of impact and just before surgical intervention have both proved to be factors indicating a poor prognosis. The clinical symptoms and signs were classified in three general types: increased intracranial pressure, brainstem dysfunction, and cerebellar disturbances. A fracture of the occipital bone was seen in 84.2% of the patients. The source of bleeding often remained undetermined, although a tear of the dural sinuses was a most frequent finding. An associated intracranial lesion was found in 39.7% of the cases, this being another factor indicating a poor prognosis. The overall mortality was 26.5%, while the surgical mortality was only 11.5%. Excellent results were achieved in 65% of the cases.

Brain Injuries↗
PubMed1982

Pineal region meningiomas without dural attachment.

A rare case of meningioma in the pineal region without dural attachment, which was successfully removed through an infratentorial supracerebellar approach, is presented. The preoperative diagnosis was made by means of computed tomography together with histographic analysis. We review similar cases reported in the literature and discuss the clinical feature, diagnostic aspects, and surgical management.

Brain Neoplasms↗