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Biomedical subjects

R Braakman

Publications and source records attributed to R Braakman.

At least 19 recordsLinked to original sources
PubMed1992

Early prediction of outcome in severe head injury.

A survey is given of the development and actual state of the prediction of outcome in severe head injury. Thanks to the data collection in some large databanks it has become possible, in a relatively large number of cases, to estimate reliably the chances of survival and the chance of developing an intracranial haematoma base on clinical data and CT obtained during the first 24 hours. Later during the posttraumatic course prediction is possible of the degree of remaining disability in survivors, and the chances of developing epilepsy and neuro-behavioural sequelae. Due to changing management-regimens further data collection in international databanks is necessary.

Activities of Daily Living↗
PubMed1992

Long-term results of transplantations to repair median, ulnar, and radial nerve lesions by a microsurgical interfascicular autogenous cable graft technique.

A comprehensive analysis of 187 patients (78 median, 86 ulnar, and 23 radial nerve lesions) treated by an interfascicular autogenous nerve grafting technique is presented. After a follow-up of at least 18 months good motor recovery was achieved in 72% of median nerve lesions, 77% of ulnar nerve lesions, and 57% of radial nerve lesions. Good functional sensory recovery was found in 36% of median, 45% of ulnar, and 48% of radial nerve lesions. It appears by multivariate analysis that the results obtained generally were better in younger patients, in patients with a shorter preoperative delay, and in cases with a shorter transplant.

Adolescent↗
PubMed1992

Mifepristone (RU 486) treatment of meningiomas.

Meningiomas are common brain tumours which are generally benign, well circumscribed and slow growing. In a minority of patients complete surgical removal is not possible and re-growth of tumour tissue is a major clinical problem. Most meningiomas contain progesterone receptors. The anti-progestational drug mifepristone (RU 486) binds to these receptors. Ten patients were treated with 12 recurrent or primary "inoperable" meningiomas, all of whom had shown recent neuroradiological and/or ophthalmological evidence of tumour growth. They received 200 mg mifepristone daily for 12 months. Most patients initially had complaints of nausea, vomiting and/or tiredness. In four patients prednisone (7.5 mg/day) was given after which these side-effects subsided. CT scan analysis of tumour size, showed progression of growth of five meningiomas in four patients, stable disease in three patients with three tumours and regression of four tumours in three patients. A decrease in the complaints of headache and an improved general well being was observed in five patients. Two patients died during the treatment period from unrelated causes. Mifepristone treatment resulted in control of tumour growth (= stable disease) in six of 10 patients who had shown recent evidence of tumour growth. In three of these six patients consistent tumour shrinkage was observed.

Adult↗
PubMed1992

CT scan prediction of neurological deficit in thoracolumbar burst fractures.

In 139 patients with burst fractures of the thoracic, thoracolumbar or lumbar spine, the least sagittal diameter of the spinal canal at the level of injury was measured by computerised tomography. By multiple logistic regression we investigated the joint correlation of the level of the burst fracture and the percentage of spinal canal stenosis with the probability of an associated neurological deficit. There was a very significant correlation between neurological deficit and the percentage of spinal canal stenosis; the higher the level of injury the greater was the probability. The severity of neurological deficit could not be predicted.

Humans↗
PubMed1991

[The effect of publications on clinical practice; chemonucleolysis].

The influence on practice of a publication about a randomised clinical trial of chemonucleolysis (CNL) vs. herniotomy in patients with lumbar prolapsed intervertebral disc was investigated, using a questionnaire sent to neurosurgeons and neurologists. There were no differences between responses of neurosurgeons and neurologists, nor between academic and non-academic specialists. 63 (57%) of the respondents stated they were not influenced by the paper, 48 (43%) stated they were. 40 of those said they thought more favourably about herniotomy, 8 more favourably about CNL. Opinion about CNL and advice to patients about CNL had no effect on being influenced or not by the article. However, they did modify the direction of influence: both negative and positive opinions about CNL appeared to be reinforced by the publication. Opinion about the best treatment and advice to patients were not fully consistent with each other.

Decision Making↗
PubMed1991

Neurological deficit in injuries of the thoracic and lumbar spine. A consecutive series of 70 patients.

Seventy consecutive patients with injuries of the thoracic and lumbar spine accompanied by neurological deficit were prospectively studied and follow-up. In 40 of these patients with a burst fracture, the degree of involvement of the cross-sectional area of the spinal canal, as revealed on first CT after admission, was not correlated with the type and degree of initial neurological deficit. In patients with injuries of the lumbar spine, neurological deficit may be mild, although the sagittal diameter of the spinal canal may be reduced by as much as 90%. We cannot establish a difference in neurological recovery between those cases who were managed conservatively and those in whom a surgical decompression and stabilization procedure was performed. Surgical stabilizing procedures, however, result in immediate stabilization of the spine, they diminish pain, facilitate nursing care and allow more rapid mobilization and earlier active rehabilitation. If major extraspinal injuries form a relative contra-indication to surgical decompression of the cord and stabilization of the spine injury, the patient can quite well be treated conservatively without endangering neurological recovery.

Follow-Up Studies↗
PubMed1991

Progesterone, oestradiol, somatostatin and epidermal growth factor receptors on human meningiomas and their CT characteristics.

The presence of progesterone, oestrogen, somatostatin and epidermal growth factor receptors of 24 meningiomas was related with their radiological CT appearance. Progesterone receptors were present in 16 of 21 (76%), oestrogen receptors in 4 of 21 (19%), somatostatin receptors on 23 of 24 (96%) and epidermal growth factor receptors on 17 of 19 (89%) meningiomas. There was no relationship between the presence of these receptors and the age or sex of the patients, tumour histology, tumour localisation, the presence of perifocal oedema, displacement of the midline cerebri or obstructive hydrocephalus on CT scan. There was a negative correlation (P less than 0.05) between the number of progesterone receptors and "malignant" behaviour of the meningiomas on CT (e.g. the presence of necrosis, cyst formation, intratumoral haemorrhage, irregular surface and/or inhomogeneous attenuation of contrast). The observation that aggressive tumour behaviour on CT is accompanied by low numbers or absence of progesterone receptors makes these meningiomas less attractive candidates for medical therapy with antiprogestins.

ErbB Receptors↗
PubMed1991

Inhibition of the growth of cultured human meningioma cells by recombinant interferon-alpha.

In this paper the results of investigations on the effect of interferon-alpha (IFN-alpha) on the growth of meningioma cells in culture is reported. A consecutive series of six meningiomas and one meningioma/neurofibroma derived from a patient with neurofibromatosis type 2 was investigated and it was found that the growth of all seven tumours in response to mitotic stimuli (fetal bovine serum or epidermal growth factor) is strongly inhibited by IFN-alpha. Maximal response varied between 100% and 70% inhibition of the incorporation of tritiated thymidine. In some cases an inhibitory response was obtained already at very low doses (less than or equal to 10 U of IFN-alpha per ml). These results indicate that further clinical investigation of the application of IFN-alpha to the treatment of meningioma is warranted.

Adult↗
PubMed1990

[Revised guidelines for the treatment of patients with severe traumatic brain injury].

The early assessment and acute treatment of patients with severe traumatic brain injury require a well structured and organized policy. This policy should include rapid transport to, and effective first aid in trauma centres especially equipped for this purpose, adequate communication of information between the (para-)medical workers successively involved and a multidisciplinary handling of diagnostics and treatment of the various traumatic and posttraumatic conditions. This requires the imposition of unequivocal priorities known to all concerned. In this paper, which was written in cooperation with the different medical disciplines concerned, the main features of the acute treatment of severe head injury, about which a wide agreement was reached, are worked out in 18 theses. The guidelines regard the admission and first aid, the diagnostic procedures and the conservative and surgical treatment of patients with severe head injury. These guidelines can be developed in the different hospitals into detailed blueprints for the treatment, in accordance with the local situation.

Brain Injuries↗
PubMed1990

Effects of progesterone on the response to epidermal growth factor and other growth factors in cultured human meningioma cells.

The presence of receptors for progesterone in a large proportion of human meningioma tissues is well established. The occurrence of increased rates of growth of meningiomas in situ during pregnancy suggests the existence of a relationship between high progesterone levels and the growth of meningiomas. However, experiments with cultured meningioma tissue (cells or explants) have shown only minimal effects of progesterone. It has been shown recently that many meningiomas have receptors for epidermal growth factor. In this paper we have investigated the response of cultured human meningioma cells to epidermal growth factor and other growth factors and the modulation of this response by progesterone and the progesterone-receptor blocking agent mifepristone (RU 38486). The results suggest that the presence of progesterone in the culture medium increases the sensitivity of meningioma cells to mitogenic stimuli, whereas mifepristone can counteract the stimulating effects of progesterone.

Adult↗
PubMed1990

Two zero-flow pressure intercepts exist in autoregulating isolated skeletal muscle.

The autoregulating vascular bed of the isolated canine extensor digitorum longus muscle was investigated for the possible existence of two positive zero-flow pressure axis intercepts, a tone-dependent one and a tone-independent one. An isolated preparation, perfused with autologous blood, was used to exclude effects of collateral flow and nervous and humoral regulation while autoregulation was left intact [mean autoregulatory gain 0.50 +/- 0.24 (SD)]. In a first series of experiments, the steady-state (zero flow) pressure axis intercept [mean 8.9 +/- 2.6 (SD) mmHg, tone independent] and the instantaneous (zero flow) pressure axis intercept [mean 28.5 +/- 9.9 (SD) mmHg, tone dependent] were determined as a function of venous pressure (range: 0-45 mmHg) and were independent of venous pressure until the venous pressure exceeded their respective values. Beyond this point the relations between the venous pressure and the steady-state and instantaneous pressure axis intercept followed the line of identity. The findings agree with the predictions of the vascular waterfall model. In a second series it was shown by means of administration of vasoactive drugs that the instantaneous pressure axis intercept is tone dependent, whereas the steady-state pressure axis intercept is not. It is concluded that there is a (proximal) tone-dependent zero-flow pressure at the arteriolar level and a (distal) tone-independent zero-flow pressure at the venous level.

Animals↗
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

A dynamic nonlinear lumped parameter model for skeletal muscle circulation.

A dynamic nonlinear lumped parameter model of the circulation of skeletal muscle for constant vasoactive state is presented. This model consists of four compartments that represent the large arteries, the arterioles, the capillaries and venules, and the veins, respectively. The first compartment consists of a linear compliance (C1) and resistance (R1). The third compartment possesses no compliance and is represented by a linear resistance (R3). The second and fourth compartments each consist of a nonlinear pressure-volume relation, resulting in a pressure dependent compliance (C2, C4, respectively) and nonlinear resistance (R2, R4, respectively). The eleven model parameters were collected in a complementary way: they were partly obtained from a priori knowledge including information at the microscopic level, and partly determined by means of an estimation algorithm. Estimated values of the compliances (in cm3.kPa-1.100 g-1, 1 kPa = 7.5 mmHg) and resistances (in kPa.s.cm-3.100 g) at an (arterial) inflow pressure of 10 kPa and a (venous) outflow pressure of 0 kPa were: C1: 0.014; R1: 6.6; C2: 0.565; R2: 84.6; R3: 37.9; C4: 1.044; R4: 24.5. The model (with the nonlinear pressure-volume relations) is able to predict the static and dynamic instantaneous (i.e., for constant vasomotor tone) pressure-flow relation and the instantaneous zero flow pressure intercept. These phenomena are therefore not necessarily the result of the rheological properties of blood. The secondary or delayed dilatation upon a positive inflow pressure step (or negative step in venous pressure) is predicted by the model implying that delayed dilatation is not necessarily related to changes in vasomotor tone. Venous outflow delay, upon a positive inflow pressure step (starting from zero flow), is also predicted by the model.

Algorithms↗
PubMed1989

Chemonucleolysis versus discectomy: a randomized multicenter trial.

A randomized clinical trial was carried out to compare the results of open discectomy with those of chemonucleolysis in 151 patients suffering from a disc herniation at L4-5 or L5-S1. All patients fulfilled strict entry criteria; 78 patients underwent open discectomy and 73 were subjected to chemonucleolysis. An increase in radicular pain immediately after treatment was encountered in 16 patients (22%) in the chemonucleolysis group, as compared to none in the discectomy group. The efficacy of discectomy appeared to be definitely superior to that of chemonucleolysis. Within a follow-up period of 1 year, 18 patients (25%) required open discectomy following failed chemonucleolysis; two patients (3%) in the discectomy group needed a second operation. Open discectomy following previous chemonucleolysis was successful in only 44% of cases. Comparison of the final results of the two modes of treatment 12 months after the last intervention (including second treatment) did not reveal any significant differences. The duration of the preoperative symptoms, the level of disc herniation, and the leakage of contrast medium out of the disc appeared to be of no relevance to the final outcome. The complication rates in both treatment groups were low.

Adolescent↗
PubMed1989

Coincidence of EGF receptors and somatostatin receptors in meningiomas but inverse, differentiation-dependent relationship in glial tumors.

Somatostatin (SS) receptors as well as EGF receptors have been shown to be present in various brain tumors such as meningiomas or glia-derived tumors. Using receptor autoradiography for both receptors, their localization on adjacent tumor sections was investigated and a correlation was attempted. In glia-derived tumors, there was an inverse relationship for the incidence of the two receptors in individual tumors: in a majority of cases (five of eight) of well-differentiated astrocytomas (I-II), SS receptors were present, but in none of the cases (zero of eight) EGF receptors were detected. In undifferentiated glioblastomas, the reverse situation was observed, no SS receptors were found (0 of 14) but EGF receptors were present in a majority of tumors (8 of 14). In astrocytomas III both types of receptors were normally seen. These data suggest that in glia-derived tumors, SS receptors are markers for the well-differentiated cases as opposed to EGF receptors. In meningiomas, SS receptors are found in all (27 of 27) tumors and EGF receptors in a large percentage (23 of 27) of the same tumors. However, in some cases a coincidence of both receptors on the same cell can be excluded. Furthermore, no effect of the SS analog SMS 201-995 on basal or EGF-stimulated growth of meningiomas in culture could be detected. Nevertheless, the coexistence of the two receptor types in meningiomas may be suggestive for a potential functional interaction between EGF and SS.

Autoradiography↗