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Biomedical subjects

J Verlooy

Publications and source records attributed to J Verlooy.

At least 37 records · Page 2Linked to original sources
PubMed1994

Instability of short tandem repeats (microsatellites) in human gliomas.

OBJECTIVE: Microsatellite instability implying multiple replication errors (RER) characterizes a proportion of familial and sporadic carcinomas. The purpose of this report is to analyze whether microsatellite instability occurred during the development of human gliomas. EXPERIMENTAL DESIGN: We checked prospectively 16 central nervous system tumors, including 10 glioblastomas and 6 astrocytomas of different malignancy grades, for genetic microsatellite instability. Fifteen different microsatellites, located on 6 different chromosomes, were investigated. All microsatellites are dinucleotide CA, repeats except for D11S956,P23 (CTAT) and CYP 19, which are tetranucleotide repeats and P23 (GTTTT) which is a pentanucleotide repeat. The repeats were analysed by PCR amplification, followed by electrophoresis on denaturing 6% polyacrylamide gels. MEASURES: We looked for all kinds of microsatellite alterations. Only microsatellite shifts were considered to represent microsatellite instability. RESULTS: Three out of 10 glioblastomas showed mobility shifts on gel electrophoresis in tumor, compared to corresponding normal DNA samples. In contrast, no microsatellite instability was found in any of the astrocytomas. Besides the presence of larger or smaller alleles, an imbalance in the ratio between alleles was noticed in one astrocytoma and in one glioblastoma multiforme. In addition, loss of heterozygosity (LOH) is observed without a fixed pattern in 3 glioblastomas. CONCLUSIONS: We conclude that genetic instability of microsatellites may be demonstrated in high grade gliomas rather than in their low grade precursors and should be regarded as an evolution in tumor progression rather than as a new mechanism for tumor initiation in gliomas.

Astrocytoma↗
PubMed1993

Failure of a modified posterior lumbar interbody fusion technique to produce adequate pain relief in isthmic spondylolytic grade 1 spondylolisthesis patients. A prospective study of 20 patients.

A modified posterior lumber interbody fusion procedure is described: this technique basically uses only two tricortical bone grafts and does not produce a distraction at the interspace while inserting the bone grafts. Twenty patients with intractable back and leg pain due to an isthmic spondylolysis and a grade 1 spondylolisthesis were operated using this technique and a prospective study with a mean follow-up of 41 months was conducted to evaluate the results. The final evaluation involved a questionnaire, a clinical examination, and a lumbar spine radiographic series. Fourty-five percent of the patients had good or excellent results whereas 55% had fair or poor results. The possible reasons for these unfavorable results are discussed.

Adult↗
PubMed1993

Photochemically-induced cerebral infarction in the rat: comparison of NMR imaging and histologic changes.

The evolution of a photochemically induced cerebral thrombotic infarction was followed in rats during the first week after the insult by means of NMR imaging and histology. Heavily T2-weighted images provided an excellent lesion detection and a high specificity for the discrimination of different histological abnormalities. The T2-weighted images showed a brain lesion evolving during the first 24 h from a homogeneous hyperintense area, histologically corresponding to diffuse vasogenic and cytotoxic oedema with concomitant neuronal necrosis, to an iso-intense area with a hyperintense seam, which microscopically correlated with increased vascular permeability at the periphery of the lesion. The hyperintense seam was observed up to day 7, but at that time coincided with gliomesodermal repair reaction which could be verified histochemically and ultrastructurally. It may be concluded that NMR-micro-imaging at a moderately high field, enables early detection and adequate follow-up of small cerebral infarctions in rats.

Animals↗
PubMed1993

Magnetic resonance characterization of a long-standing pituitary abscess.

A 56-year-old male patient with panhypopituitarism is presented. Magnetic resonance (MR) examination of the pituitary region revealed a pituitary mass with markedly increased signal intensity on T1-weighted images and low signal intensity on T2-weighted images. At surgery, a large amount of purulent material was removed. At light microscopy, the tissue was demonstrated to be a pituitary abscess occurring in an otherwise normal pituitary gland. The high signal intensity on T1-weighted images does not correspond to the only MR description of a pituitary abscess given until now, reporting a mass isointense to white matter. These signal characteristics could emanate from the presence of small amounts of blood breakdown products in the proteinaceous content of the abscess. MR appearance of a pituitary abscess is possibly aspecific and could depend on the pathological composition of the lesion.

Aged↗
PubMed1993

Benign intracranial hypertension as a cause of transient partial pituitary deficiency.

A male patient is reported with benign intracranial hypertension, who presented with three periods of partial pituitary deficiency, corresponding to episodes of headaches and papilledema. No radiological signs of the empty sella syndrome were observed. Since benign intracranial hypertension has been implicated in the development of the empty sella syndrome, it is postulated that the endocrine deficiency syndrome encountered in the empty sella syndrome can be provoked by chronic intracranial hypertension in itself and is not necessarily secondary to the anatomical changes occurring in the sellar region.

Adult↗
PubMed1993

The association of meningioma and pituitary adenoma: report of seven cases and review of the literature.

Seven patients with the co-occurrence of meningioma and pituitary adenoma are reported. Diagnosis was based on histological examination and if not available on MR imaging. Extensive review of the literature reveals only 18 other cases with this association if meningiomas appearing after radiation therapy for pituitary tumors are excluded. As in isolated meningiomas, the female-to-male ratio is high. A preponderance of perisellar meningiomas is apparent. Another distinct characteristic of this combination is not revealed, since no specific typing of the meningioma and no specific endocrine syndrome is uncovered. Two patients presented with multiple meningiomas, of which one showed two histologically different tumor types. The presence of other tumors in association with pituitary adenomas and meningiomas in our series is striking and could suggest a genetic dysregulation leading to the development of these tumors.

Adenoma↗
PubMed1992

The course of vasospasm following subarachnoid haemorrhage in rats. A vertebrobasilar angiographic study.

The course of vasospasm following subarachnoid haemorrhage in rats was studied using vertebrobasilar angiography. Wistar and Sprague Dawley rats were compared with respect to vasospastic response after bleeding. A more pronounced vasospasm was found in Sprague Dawley rats. In order to avoid a possible toxic effect on the contrast medium, only one angiogram per animal was initially performed. However, a comparison with the results obtained in a separate series of non-challenged animals demonstrated a difficulty due to high variability in basilar artery size in the latter group. Therefore, vasospasm can be more readily shown if multiple angiograms are used in the same animal so that the vasospasm can be expressed as a percentage of the initial diameter of the basilar artery. It was found that multiple angiograms are well tolerated when non-ionic contrast media are used.

Animals↗
PubMed1992

Haemodynamic, intracranial pressure and electrocardiographic changes following subarachnoid haemorrhage in rats.

Experimental induction of subarachnoid haemorrhage in rats resulted in acute haemodynamic changes. Heart rate decreased concomitantly with a rise in arterial blood pressure. Intracranial pressure increased and consequently cerebral perfusion pressure dropped. These changes as well as the observed electrocardiographic (ECG) changes were comparable to those reported in patients. Apart from blood also saline, when introduced into the cisterna magna, was able to elicit such abnormalities. The haemodynamic and electrocardiographic changes, which result from subarachnoid haemorrhage, may even become aggravated, when repetitive injections of blood or saline are given into the cisterna magna and when cerebral angiography is performed prior to induction of the subarachnoid haemorrhage. Chronic intracranial pressure monitoring during the 48 hours following subarachnoid haemorrhage revealed no significant rise in pressure. A thorough control of the experimental conditions is thus of utmost importance in order to give a valid interpretation of the observed anomalies.

Animals↗
PubMed1992

[Problems with flute playing: an otological problem? Case report of a peculiar cerebellar astrocytoma].

A rare case of cerebellar astrocytoma presenting as a cerebellopontine angle tumour is discussed. A 35-year old woman noticed a bizarre twitching and fatigability of the left upper lip while playing the flute. There was also a mild hearing loss on the left side and she sometimes felt unsure of herself when walking. A thorough examination by means of speech audiometry, electronystagmography, ABR, CT-scan and MRI revealed a large, partly calcified mass occupying the cerebellopontine angle. Only the histological examination of the surgical specimen revealed the true nature of the tumour. The special characteristics of this tumour and the unusual clinical course are discussed. The importance of a good histological diagnosis is stressed.

Adult↗
PubMed1991

Singlet oxygen induced cerebral vasospasm: an experimental study in rats.

A new experimental model is described which can be used as an alternative to study the effects of subarachnoid hemorrhage (SAH) in rats. Vasospasm of the basilar artery is induced photochemically after transpalatal illumination of intracisternally injected rose bengal in two different rat strains. Singlet oxygen, generated in the subarachnoid space, elicits vasospasm which has been demonstrated angiographically at 90 min and 24 h after photosensitisation. Sprague Dawley rats responded better than Wistar rats. Dilution of rose bengal in water was more vasospastic than dilution of rose bengal in artificial CSF. Since the action of singlet oxygen is similar to that of free radicals, this experiment gives an argument for the hypothesis that free radicals play a leading role in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage.

Animals↗
PubMed1990

Fiberoptic intracranial pressure monitoring in rats.

An adaptation of a fiberoptic intracranial pressure monitoring system for clinical use is described. The method allows easy and reliable acute and chronic intracranial pressure registration in anesthetized as well as conscious rats. The disposable fiberoptic probes, originally designed for human use, can be re-used limitlessly. The fiberoptic method is compared with conventional monitoring procedures under different experimental conditions. The validity of intraparenchymal and epidural measurements is discussed. The importance of chronic intracranial pressure registration in conscious laboratory animals is stressed.

Animals↗
PubMed1990

Consequences and complications of glycerol injection in the cavum of Meckel: a series of 120 consecutive injections.

From 1983 to 1989, 120 injections of glycerol into the trigeminal ganglion were performed to treat facialgias of different origin. The subjective and objective consequences and complications are reviewed. Since this operation yielded most often mild, transient and well tolerated consequences and complications for the patient, we now propose this method as first choice for trigeminal neuralgia when there is no anamnestic or clinical evidence of damage to the trigeminal system.

Adolescent↗
PubMed1989

Lazarus sign and extensor posturing in a brain-dead patient. Case report.

A man was declared brain dead after having sustained a gunshot wound to the head. All clinical criteria for the diagnosis of brain death were met. The electroencephalogram was isoelectric, and four-vessel angiography demonstrated the absence of cerebral blood flow. However, stereotypic spontaneous movements were observed which persisted for several hours. The possible mechanism is discussed and a short review of the literature is given.

Brain Death↗