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Biomedical subjects

W J Bock

Publications and source records attributed to W J Bock.

At least 55 records · Page 3Linked to original sources
PubMed1988

Intrahemispheric gradients of brain tissue pressure in patients with brain tumours.

The authors report on 14 patients in whom cerebral tissue pressure was recorded after operation for brain tumours. Cerebral tissue pressure was recorded by a 5 French catheter with two microtransducers. The transducers were placed intraoperatively in the wall of the tumour cavity and in a distance of approximately 2.5 cm. Differences between both pressures from 4 to 28 mmHg were observed. They were higher in patients with glioblastomas and meningiomas than in patients with intracranial metastases. In 7 patients proximal tissue pressure was higher than distal. In 4 patients the contrary was observed. Discussing the literature the authors think intrahemispheric changes of brain water content, blood flow, and brain tissue elastance to be responsible for this phenomenon.

Adult↗
PubMed1988

Tomographic studies of rCBF with [99mTc]-HM-PAO SPECT in patients with brain tumors: comparison with C15O2 continuous inhalation technique and PET.

In 10 patients with malignant gliomas, the intracerebral distribution of [99mTc]-hexamethylpropylene-amine oxime [( 99mTc]-HM-PAO) was studied with single photon emission computed tomography (SPECT) in comparison with C15O2 steady-state inhalation technique to measure cerebral blood flow using positron emission tomography (PET). In all instances, the cerebral [99mTc]-HM-PAO distribution was comparable with the regional pattern of cerebral blood flow (rCBF) observed with PET. This was confirmed by a significant correlation of tumor to cortex and tumor to white matter ratios between these two experimental methods. However, the contrast between high and low activity regions in the SPECT scans was significantly less than that in the PET scans. Contrast enhancement of the SPECT scans was accomplished using a correction formula proposed by Lassen.

Brain Neoplasms↗
PubMed1988

[The energy consumption of patients with craniocerebral trauma and spontaneous intracranial hemorrhage in the early postoperative post-traumatic phase].

Indirect calorimetry was performed during the first five days after admission in 18 neurosurgical patients with isolated head - injuries (N = 7) and spontaneous intracranial hemorrhages (N = 11) to determine basal metabolic rates (BMR). In the study group each day BMR varied from 2143 +/- 636 kcal/day to 3371 +/- 1140 kcal/day. Most patients however showed BMR values between 2000 and 2500 kcal/day. Individually BMR values ranged from 60 to 340 percent of normal healthy individuals. Patients with isolated head - injuries showed significant higher metabolic rates than patients with spontaneous intracranial hemorrhages. The authors conclude that an caloric intake of 2000 to 2500 kcal/day is sufficient for parenteral nutrition and usually helps to avoid negative effects of hyperalimentation by overestimation of BMR in this special patient group.

Adult↗
PubMed1987

Magnetic resonance imaging of colloid cysts of the third ventricle.

Two cases of colloid cyst of the third ventricle are reported. Their computed tomographic (CT), magnetic resonance (MR) and neuropathological features are presented. The MR findings were different in the two cases for reasons not yet fully explained, full biochemical and biophysical analyses of the cyst contents not being available. Neuropathologically, the only significant difference was the abundant presence of cholesterin crystals in the colloid of case 1 and their absence in case 2. One of our cases is also peculiar from a CT point of view, since it was primarily hypodense and did not enhance on intravenous contrast administration.

Brain Diseases↗
PubMed1987

A practical technique for continuous monitoring of cerebral tissue pressure in neurosurgical patients. Preliminary results.

A new technique for continuous monitoring of cerebral tissue pressure is presented. It is based on a new type of piecoresistive microtransducer with low baseline and temperature drifts. In 7 patients cerebral tissue pressure and ventricular fluid pressure were recorded simultaneously. Comparison of these two different pressures showed extremely good correlation with coefficients always better than 0.95. Due to another type of pulsewave cerebral tissue pressure was constantly 4 to 12 mm Hg lower than ventricular fluid pressure. Routine use of cerebral tissue monitoring in 12 neurosurgical patients with brain tumours postoperatively showed good clinical correlation of cerebral tissue pressure without any additional complications. The authors recommend continuous monitoring of cerebral tissue pressure as a safe and simple method of intracranial pressure monitoring in neurosurgery.

Brain Diseases↗
PubMed1987

The influence of magnetic resonance tomography on diagnosis and therapy in patients with intracranial manifestation of neurofibromatosis (Recklinghausen disease).

Recent research into the natural course of neurofibromatosis has revealed an outstandingly high proportion of central nervous system malignancies as well as cancers of various other organs. Due to the lack of ionizing radiation, the extraordinary reconstruction in the frontal and parasaggital planes as well as the diagnosis of intracanalicular acoustic neurinomas and intraorbital tumors, magnetic resonance tomography (MRT) is indicated for control of patients with neurofibromatosis.

Adolescent↗
PubMed1987

[Continuous registration of intracranial pressure using disposable transducers].

The authors report the results of physical tests (baseline drift, temperature drift, absolute accuracy) and clinical experiences in intraventricular intracranial pressure monitoring with disposable transducers. Physical tests gave excellent results concerning baseline drift (less than 1%), temperature drift (0.35 mmHg/degrees C), and absolute accuracy (+/- 2 mmHg) in the range of intracranial pressure of both transducers tested (Gould DTX and Cobe 41-500). Clinical testing gave corresponding values compared with routine methods of ventricular pressure monitoring via a Bentley-Trantec-Transducer. As a result of the study disposable pressure transducers are recommended for routine use in clinical practice of intraventricular intracranial pressure monitoring.

Brain Injuries↗
PubMed1987

[Cerebrospinal fluid and plasma aminograms in patients with primary and secondary tumors of the CNS].

16 different free amino acids were determined in cerebrospinal fluid and plasma of each 5 patients with glioblastomas, meningiomas, and low grade gliomas as well as in 21 patients with lumbar disk herniations (control group). The values from the control group were in good accordance with those previously observed in normal adults of 5 studies of the literature. Significant changes were seen only in 6 of 16 amino acids. Absolute values of free CSF amino acids showed significant lower levels of valine, leucine and asparagine in the 3 subgroups whereas serine remained constantly high. The greatest changes were observed in glioblastoma and meningioma patients. Relative values gave similar results. No significant changes were found in CSF-plasma free amino acid relations. The authors conclude that changes of free CSF amino acids are due to a non-specific reaction of the brain itself to tumor growth. The different histology of the tumor does not give specific results. Determination of free CSF amino acids may help in early diagnosis of brain tumor recurrence after operation and to watch the effect of chemotherapy and radiation on brain tumor growth.

Adult↗
PubMed1986

Secondary intraventricular haemorrhage in blunt head trauma.

Intraventricular haemorrhage (IVH) has been detected by computed tomography (CT) in 225 patients admitted to our clinic from 1977 to 1985. In 9 patients IVH was caused by trauma. We report two cases in whom IVH occurred after a lucid interval of about 10 hours postinjury. The pathogenesis of traumatic IVH is discussed comparing these cases with a review of the literature.

Adult↗
PubMed1986

[Computerized tomography of intracranial tuberculous lesions. 2 case reports].

In contrast to the numerous publications on supratentorially located tuberculomas, reports on infratentorial tuberculomas, demonstrated by computed tomography, are relatively few in number. Although nowadays precise localization has become possible via computed tomography, a tuberculoma cannot be identified unequivocally by computed tomography. The appearance of tuberculous lesions in CT depends on the extent the lesion has advanced at the time of the investigation and whether or not tuberculostatics have already been administered. In the posterior cranial fossa, brain stem tuberculomas must additionally be distinguished from cerebellar tuberculomas and tuberculous brain abscess from solid tuberculomas. The problem of tuberculous lesions in computed tomography is discussed with reference to a left frontotemporal tuberculoma and a vermis tuberculoma demonstrated by computed tomography and removed surgically.

Adult↗
PubMed1986

Intra-arterial chemotherapy with ACNU for the treatment of glioblastoma. Preliminary experience.

In November 1985, we started a study of intra-arterial (i-a) chemotherapy with ACNU for the treatment of glioblastomas of the central nervous system: 19 patients with histologically proved glioblastoma and recurrent, progressive or newly diagnosed disease were entered. Five patients were treated three times. We observed reduction of mass effect, of neovascularization, and of contrast enhancement. As to the time of survival, or follow-up is too short to allow definite conclusions. The quality of life in those patients who received several courses of chemotherapy, did not deteriorate as evidenced by a constant Karnofsky performance rating score. Systemic complications of i-a chemotherapy were negligible. However, some severe side-effects were seen: cerebral ischemia in two cases, and amaurosis in one. Direct ACNU related neurotoxicity was not seen to the present. According to these preliminary results, we feel encouraged to treat further patients with i-a chemotherapy, particularly in view of the disappointing results of several other treatment modalities in the management of glioblastomas of the brain.

Adult↗
PubMed1985

Measurements of brain-stem auditory evoked potentials in infancy, childhood, and adolescence.

Brain-stem auditory evoked potentials (BAEPs) were measured in 38 patients between 3 months and 18 years of age. In patients with blunt head injuries (N = 28; 73.7%) no significant correlation between BAEP changes and final outcome could be established until day 36 with the exception of wave III changes in 3 children. Because various BAEP abnormalities occurred in all outcome groups and the nature of the changes was transient, we conclude that within this age group there must be a higher resistance to various lesions until irreversible impairment of brain-stem function results. In spite of this result, continuous BAEP recording in this age group appears useful, since this noninvasive investigation represents an objective assessment of topical brain-stem function.

Adolescent↗
PubMed1985

Protein and amino acid metabolism after severe cerebral trauma.

Fourteen patients (20-48 years) suffering from severe head injury were followed for changes in amino acid and protein metabolism during the first 8 days after trauma. All patients received a standardized intravenous nutrition containing 15.7 g of nitrogen per day and additional carbohydrates. Electrolytes, free water, and blood constituents were given as needed. Additional treatment included surgical decompression of space-occupying hematomas, high dose dexamethasone therapy, and controlled hyperventilation for at least 5 days. Gross changes of protein metabolism were observed particularly on the days 5 and 6. The duration and chronological sequence of these changes are different from those usually found in patients with multiple injuries.

Adult↗
PubMed1985

Cerebrospinal fluid free amino acids in patients with spinal space-occupying lesions. A preliminary report.

18 different free amino acids were determined in the cerebrospinal fluid of 28 patients with various spinal space--occupying lesions. The study group included 15 patients with lumbar disc lesions (control group), 8 patients with cervical radiculopathy, 4 patients with cervical myelopathy, and 1 patient with a thoracic spinal angioma. The values from the control group were in general accord with those previously observed in normal adults of 5 studies of the literature. Comparison of the values in the different subgroups showed normal values of all amino acids in patients with cervical myelopathy, and significantly higher levels of glutamic acid in patients with cervical radiculopathy. In the case of a thoracic spinal angioma however most free amino acids were extremely high. The authors conclude that this may be due to alterations of the spinal metabolism and that determination of free amino acids in CSF of patients with intradural spinal lesions may help to improve preoperative diagnosis in addition to neuroradiological methods.

Adult↗
PubMed1985

[Monitoring of auditory function in comatose patients in therapy with potentially ototoxic substances using acoustically evoked brain stem potentials].

Brain-stem auditory evoked potentials were measured in 14 comatose patients treated with aminoglycosides in cases of bronchopulmonary infection. Patients treated with tobramycin showed little influences on the latencies of wave 1, whereas treatment with amikacin resulted in enhanced wave 1 latencies even after completion of therapy. These changes were observed with therapeutic plasma levels of the aminoglycosides in all cases. As a method of bedside monitoring of auditory function with no additional stress to the patient with immediate results monitoring brain-stem auditory evoked potentials is recommended as a routine method to control auditory function in comatose patients under administration of aminoglycosides.

Adult↗
PubMed1984

[A physical model on the problem of the slipped clip].

The authors present their physical concept of determining the blade pressure of various aneurysm clips. On the basis of this concept, the consequences for the practical use of such clips are discussed. A new clip for aneurysm surgery is presented.

Biomechanical Phenomena↗