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G Blaauw

Publications and source records attributed to G Blaauw.

At least 37 records · Page 2Linked to original sources
PubMed1990

Histogenesis of intracranial haemangiopericytoma and haemangioblastoma. An immunohistochemical study.

An immunohistochemical study was performed on three meningeal haemangiopericytomas and four cerebellar haemangioblastomas (paraffin embedded) in an attempt to elucidate the uncertain histogenesis of these tumours. The tumour cells of all meningeal haemangiopericytomas show no expression of alpha-smooth muscle actin and, thus, no immunohistochemical proof of their true pericytic nature can be obtained. The stromal cells of cerebellar haemangioblastomas show foci of positive staining for S-100 protein, neuron-specific enolase and synaptophysin, thereby clearly indicating their neuroectodermal origin. These results allow the conclusion that the present nomenclature of these tumours is at least arguable and probably incorrect.

Cerebellar Neoplasms↗
PubMed1990

Computed tomography-guided and stereotactic techniques in the diagnosis and treatment of cerebral tuberculoma.

The advantages of computed tomography-guided preoperative localization of brain lesions are illustrated in four cases of solitary tuberculoma and in one case of tuberculous abscess of both the cerebrum and the cerebellum. The role of stereotactic diagnostic techniques is emphasized. The clinical presentation and the computed tomography findings in these patients were equivalent to those from glial or metastatic tumors. Synchronous pulmonary tuberculosis was not present in these patients, but in three patients there was metachronous tuberculosis. Tuberculous meningitis had not developed in any of the patients.

Adult↗
PubMed1990

Growth hormone secretion patterns in relation to LH and testosterone secretion throughout normal male puberty.

Pulsatile growth hormone secretion patterns were studied in relation to LH and testosterone release in 30 healthy prepubertal boys and 2 adult men. Plasma GH was measured every 10 min, plasma LH and testosterone every hour. Night-time GH secretion parameters were 2-3 times higher than daytime values. During daytime, mean GH level and the fraction of GH in pulses increased from Tanner stage G2 to G4 (p = 0.01); during night-time these parameters increased as well (p less than or equal to 0.1) and decreased from stage G5 to adulthood (p = 0.05). GH pulse number did not increase; the number of high-amplitude (greater than 8 micrograms/l pulses, however, increased from stage G2 to G4 (p = 0.05) during the day. Height velocity correlated with their number of high pulses during day and night (tau = 0.39, p less than 0.003). From stage G2 to G4 significant correlations were observed between nocturnal testosterone levels and GH secretion parameters (tau = 0.53-0.57), in contrast to nocturnal LH levels. It is concluded that during puberty 1. GH secretion increases as a result of an increased pulse amplitude; 2. there is no consistent correlation between GH and LH levels; 3. increasing nocturnal testosterone levels are correlated with the increasing GH secretion; therefore GnRH does not seem to influence GH secretion directly, but an indirect effect via testosterone is more conceivable, and 4. height velocity is correlated with the number of high GH pulses.

Adolescent↗
PubMed1989

[Patients' condition one year following surgery for a lumbosacral radicular syndrome].

In 492 patients with a lumbosacral radicular syndrome caused by a lumbar intervertebral disc herniation or by a stenosis of the lumbar spinal canal, the situation 1 year after a root decompressing operation was compared with the situation before surgery. About 75% of the patients reported satisfactory improvement, while about 10% were not satisfied. The judgement of the physicians is somewhat more favourable: 80% and 5%, respectively. The best results are obtained in patients in whom the preoperative diagnosis of lumbar disc herniation is highly probable; the worst results are obtained in patients undergoing a second operation. Back pain, sometimes serious, persists after surgery in about 50% of the patients. Such persistent back pain occurs most frequently in patients with a lumbar canal stenosis; one-third even mention a postoperative increase in back pain. About 50% of the patients who were on sick leave before operation resumed work afterwards.

Adult↗
PubMed1989

[Effect of surgery on neurological involvement caused by a lumbosacral radicular syndrome].

Results of neurological assessment one year after surgical treatment of herniated lumbar intervertebral disc and lumbar stenosis are reported in 443 patients. Follow-up was performed during one year after operation. Preoperatively, surgeons found motor loss more frequently than patients, (28 and 12% respectively) and, postoperatively, motor loss was still present in 25% and 24%, respectively, of these cases. The operation had caused motor loss in 5% and aggravated motor loss in 3%. Sensibility was reported as abnormal one year after surgery by both patients and surgeons in one-third of the cases. Sensory loss, considered by the patient to have been caused or aggravated by the operation, occurred in 15% of the cases and in 12% of these the surgeons agreed. Preoperatively, unilaterally diminished knee and Achilles tendon reflexes were found in 9% and 42% respectively; one year after surgery, these had recovered in 65% and 57%, respectively. Surgery caused or aggravated unilaterally diminished knee or ankle jerks in 3% and 10%, respectively.

Adult↗
PubMed1989

[Intracranial tuberculoma, a special space-occupying process].

In four men and in one woman we found an intracranial local tuberculous infection (4 tuberculomas and 1 tuberculous abscess) in the period 1982-1988. Clinical presentation and computer tomography do not allow discrimination of intracranial tuberculomas from other space-occupying lesions. The value of the stereotactic biopsy for the diagnosis is emphasized and some characteristics of this intracranial process are discussed.

Adult↗
PubMed1988

Pitfalls in diagnostic stereotactic brain surgery.

Some of the problems and dangers inherent to stereotaxis are discussed in a series of 243 procedures. Neurological deterioration, either due to haemorrhage or to traumatic oedema, was rare. One fatal accident occurred. Infections were not present although the patient's head was not shaved. Provided he can manipulate the proper instruments accurately stereotaxis can nowadays be performed by any surgeon who can make a burr hole and perform simple arithmetic calculations. This procedure can be considered to lie within the scope of any neurosurgeon.

Biopsy↗
PubMed1988

Chondroblastoma of the temporal bone.

A chondroblastoma within the temporal bone in a 16-year-old boy is reported. The tumor recurred after intracapsular resection and curettage. After reoperation, radiotherapy was performed. The data from 137 cases of chondroblastoma are summarized.

Adolescent↗
PubMed1988

Changes in radicular function following low-back surgery.

Results of neurological assessment 1 year following surgical treatment of herniated lumbar intervertebral discs and lumbar stenosis are reported in 443 patients. The data were collected using separate series of questionnaires to be completed by the patient and the surgeon. Preoperatively, motor loss was reported by 12% of patients, while surgeons found motor weakness in 28%. Postoperative motor loss was still present in 24% and 25% of these cases, respectively; the operation had caused or aggravated motor loss in 5% and 3% of cases, respectively. Sensory phenomena were reported by 53% of the patients, while surgeons found sensory loss in 45%. Sensation was reported as abnormal 1 year after surgery both by patients and by surgeons in one-third of these cases. Sensory loss, considered by the patient to be caused or aggravated by operation, occurred in 15% of cases and in 12% of cases the surgeons agreed. Preoperatively, unilaterally diminished knee and Achilles tendon reflexes were found in 9% and 42%, respectively; at 1 year after surgery, these had recovered in 65% and 57% of cases, respectively. Surgery caused or aggravated unilaterally diminished knee or ankle jerks in 3% and 10% of cases, respectively.

Humans↗
PubMed1987

Lumbar disk herniation: diagnosis with CT or myelography.

The value of computed tomography (CT) and myelography as single investigations in the diagnostic evaluation of patients with radiating leg pain probably due to lumbar disk herniation (LDH) has been adequately demonstrated. However, the extent to which CT can replace myelography and the conditions in which the examinations should be combined and in which order are still uncertain. Results of CT scans and myelograms from 461 patients with symptoms of lumbar root compression, probably due to LDH, were evaluated and compared with surgical results, if available. The sensitivity of myelography exceeded that of CT (82% vs. 73%), but its specificity was lower (67% vs. 77%). The positive predictive value of myelography only slightly differed from that of CT (93% vs. 94%). These results were used to establish a sequential diagnostic workup for patients with radiating leg pain. If, in this population with a high prior probability for surgery, CT had been the investigation of first choice in patients suspected of having LDH, the number of myelographic procedures performed could have been reduced by two-thirds.

Adult↗
PubMed1986

Influence of transsphenoidal hypophysectomy on visual deficit due to a pituitary tumour.

The effect of transsphenoidal hypophysectomy is presented in 60 patients with visual impairment due to a pituitary adenoma, derived from a total series of 194 patients. The preoperative visual acuity and visual fields were compared with those one year after operation. The visual field loss was estimated using a semi-quantitative method. Seventy-two eyes had diminished visual acuity, and this improved in 45 eyes (63%). Visual field loss was present in 102 eyes and this improved in 71 eyes (70%). Improvement of either visual acuity and/or visual field was found in 84 eyes (78%). In 16 patients (27%) vision became normal after operation. Improvement of the visual acuity was usually accompanied by an improvement in the visual fields.

Adenoma↗
PubMed1986

Sex steroid receptors in human meningiomas.

Results of experiments on the presence of steroid receptors in a series of 67 meningioma tissues, which were derived from 64 patients are presented. All tissues were studied using dextran-coated charcoal adsorption and Scatchard plot analysis. Progestin receptors were present in a high concentration in more than 80% of the specimens. Very low concentrations of an oestrogen binding agent were found in a limited number of samples. Thus, most meningiomas contain high levels of progestin receptors in the virtual absence of oestrogen receptors. Relations were not observed between progestin receptor-content and the age and sex of the patients, or the location and the histological type of the tumour. The role and action of progestin on meningiomas is still unknown. The presence of progestin receptors, however, suggests that meningioma may be regarded as a true target tissue for progestins.

Breast Neoplasms↗
PubMed1986

High incidence of somatostatin receptors in human meningiomas: biochemical characterization.

Thirteen human meningiomas were tested for their content of specific somatostatin (SRIH) receptors using an in vitro binding assay with meningioma homogenates as well as receptor autoradiography. All tumors had measurable amounts of somatostatin receptors. Receptor density, however, greatly varied among the tumors, ranging from low levels to more than 400 fmol/mg protein. Seven tumors, biochemically characterized in detail, had saturable and high affinity receptors [mean Kd, 1.10 +/- 0.42 (+/- SEM) nM], with pharmacological specificity for SRIH resembling the noncentral nervous system type of SRIH receptor. There was no correlation between the density of SRIH receptors and the density of progestin receptors measured in parallel. The presence of SRIH receptors in meningiomas was completely unexpected, and their role unknown. If the receptors can mediate antiproliferative properties in meningiomas, as has been suggested to be the case for such receptors in other endocrine tumors, the present data could be of potential therapeutic interest.

Adult↗
PubMed1986

Search for estrogen receptors in human meningioma tissue sections with a monoclonal antibody against the human estrogen receptor.

Meningiomas are rich in progestin receptors, whereas estrogen receptors (ER) are virtually undetectable. The present experiments were performed to evaluate whether the absence of ER from the majority of human meningioma cytosols can be attributed to: occurrence of only a small number of ER-positive cells in an otherwise ER-negative tissue; resistance of nuclear receptors to extraction; or impairment of steroid binding. Twenty-one specimens were selected from our total series of 67 meningiomas. Based on cytosol assays, five of these meningiomas were considered to be ER positive (10-42 fmol/mg protein) and five had marginal ER concentrations (4-9 fmol/mg protein), whereas the remaining tissues were ER negative. For comparison, human breast cancer tissues were used. Tissues were sectioned at 6 micron and stained immunocytochemically using a monoclonal antibody against the human ER. The breast cancer specimens showed specific nuclear staining in part of the tumor cells. The sensitivity of the immunocytochemical assay was found to be sufficient to detect staining in breast cancer tissues containing as little as 17 fmol ER/mg cytosol protein. No specific staining was observed in meningioma tissues. It is concluded that the majority of meningiomas are truly devoid of ER and that the estrogen binding agent detected in low concentration in some meningioma cytosols is immunologically different from the human breast cancer ER. The presence of progestin receptors in meningioma apparently does not require the continuous presence of ER.

Antibodies, Monoclonal↗
PubMed1984

Isolation of large numbers of dispersed human pituitary adenoma cells obtained by aspiration.

Since the extent of in vitro experiments with human pituitary adenoma cells is often limited by the small number of cells isolated from surgical specimens, ways to obtain more cells are of interest. In this study we made use of tumor tissue removed by aspiration through a suction tube during transsphenoidal surgery. Fifteen out of 28 adenomas could be dispersed without enzymatic treatment. The other 13 adenomas were mildly treated with Dispase. The large number of red blood cells present in the suction tube were removed by Ficoll-Isopaque density centrifugation. More than 90% of the adenoma cells were recovered from the interphase fraction. This material, in contrast with fragments obtained with a forceps, yielded 35.9 (+/-9.0) X 10(6) cells (mean +/- SE, n = 28). Usually less than 10% of these cells were mononuclear leucocytes. Pituitary hormones other than those hypersecreted in vivo were not found in the incubation media; only small amounts of LH were found in 5 out of 25 adenomas. A linear relationship was found between cell concentration and hormone secretion, both for PRL and GH. In vitro hormone secretion by the adenoma cells was in good agreement with in vivo dynamic tests. In longterm culture, GH and ACTH secretion by the adenoma cells declined, while PRL secretion was fairly constant. It is concluded that large numbers of dispersed pituitary adenoma cells can be obtained from the material removed by suction during transsphenoidal operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1984

Progestin and estrogen receptors in human meningioma.

Progestin receptors (PR) were detected with a dextran-coated charcoal assay and Scatchard plot analysis in 40 of 45 cytosols from human meningioma. The mean PR level in samples from female patients (297 +/- 104 fmol/mg protein; mean +/- SEM; n = 28) was not different from that in samples from male patients (190 +/- 76; n = 12). No differences were observed in the PR content of meningiomas resected from different locations. In the three cases studied, nuclear progestin binding was also detected. An estrogen-binding component was detected in the cytosol of 7 of 44 samples, but the binding capacity was relatively low (13 +/- 13 fmol/mg protein; mean +/- SD). During isoelectric focusing only part of this binding component behaved as might be expected from a true estrogen receptor. Nuclear estrogen binding was not observed in two samples with detectable cytoplasmic estrogen binding. The presence of both cytoplasmic and nuclear PR suggests that in meningioma a functionally active progestin-receptor system comparable with that in other progestin target tissues is operating. In contrast to these other tissues, however, the synthesis of PR in meningioma may not be influenced by estrogens. Further research should focus on evaluating whether the growth rate of meningiomas can be modulated by antiprogestins.

Cell Nucleus↗