A "soap bubble" tumour in the brain: isolated cerebral immunocytoma.
Explore the source record for details and available documents.
Brain Neoplasms↗
Biomedical subjects
C A Tulleken
Publications and source records attributed to C A Tulleken.
High-flow bypass using nonocclusive excimer laser-assisted end-to-side anastomosis of the external carotid artery to the P1 segment of the posterior cerebral artery via the sylvian route. Technical note.
In a patient with a giant aneurysm of the basilar artery trunk, a vein graft was interposed between the external carotid artery in the neck and the P1 segment of the posterior cerebral artery. Balloon occlusion of both vertebral arteries was performed 3 days later. The sylvian route was used for the grafting procedure and the connection to the posterior cerebral artery was made by using the excimer laser-assisted nonocclusive anastomosis technique.
Adult↗
S-phase fraction, 5-bromo-2'-deoxy-uridine labelling index, duration of S-phase, potential doubling time, and DNA index in benign and malignant brain tumors.
Seventy-one histologically malignant brain tumors, 52 histologically benign brain tumors, and 14 cerebral metastases were characterized according to DNA content and proliferative capacity. DNA ploidy, DNA index (DI), S-phase fraction (SPF), 5-bromo-2'-deoxy-uridine (BrdUrd) labelling index (LI), duration of S-phase (Ts), and potential doubling time (Tpot) were assessed by flow cytometry (FCM). In histologically benign tumors, a high percentage of DNA diploid tumors and a low proliferative capacity in DNA diploid tumors were found. Histologically malignant tumors and cerebral metastases were both found to be characterized by a low percentage of DNA diploid tumors and a high proliferative capacity in DNA diploid tumors. The proliferative capacity of DNA aneuploid benign tumors and that of DNA aneuploid malignant tumors, however, appeared not to differ significantly. The number of DNA aneuploid tumors was small. Duration of S-phase was short (range 3.9-4.7 hr) and appeared not to differ between the three groups. From this, the observed differences in Tpot values should be accredited mainly to differences in LI. High-grade as well as low-grade gliomas both appeared to be characterized by malignant (FCM) features, i.e., 1) a high percentage DNA aneuploidy, 2) a high mean DI (for DI > 1), and 3) a high proliferative capacity.
Aneuploidy↗
How many residents shall we train? The Netherlands experience.
Explore the source record for details and available documents.
Cross-Cultural Comparison↗
Nonocclusive excimer laser-assisted end-to-side anastomosis.
BACKGROUND: High-flow extraintracranial bypass operation on the brain is a risky procedure because of the temporary occlusion of the intracranial portion of the internal carotid artery. We therefore developed a nonocclusive anastomosis technique in the experimental animal laboratory in 100 chronic and acute experiments in rabbits. METHODS: In 40 patients we interposed a venous transplant between the external carotid artery or one of its branches and the intracranial portion of the internal carotid artery. During the construction of the distal anastomosis the recipient artery was not occluded. The donor vessel was stitched to the exterior of the recipient vessel and an Excimer laser catheter (Medolas GmbH, Amberg, Germany) was introduced by way of an artificial side branch. The tip of the laser catheter created a hole in the wall of the recipient artery just inside the anastomosis. The cut-out full-thickness portion of recipient vessel wall remained attached to the tip of the laser catheter by way of high vacuum suction and was removed together with the laser catheter. The artificial side branch was occluded with a hemostatic clip. No interruption of blood flow in the recipient artery was induced during the making of the anastomosis. RESULTS: The procedure was well tolerated by the patients and a high patency rate was observed. CONCLUSIONS: The nonocclusive Excimer laser-assisted anastomosis technique is safe and yields a high long-term patency rate in neurosurgical patients. It cannot be excluded that there are indications for this method in coronary bypass surgery.
Anastomosis, Surgical↗
The effect of intracranial pressure on myelination and the relationship with neurodevelopment in infantile hydrocephalus.
The effect of raised intracranial pressure (ICP), due to infantile hydrocephalus, on the process of myelination has been suggested in the literature. In this study 19 hydrocephalic infants were followed-up with anterior fontanelle pressure (AFP) measurement (assessment of ICP), MRI (assessment of the myelination process and the CSF volume), and neurodevelopmental testing (NDT). There was a high correlation (r = 0.80) between the myelination and NDT scores. The size of the CSF volume showed a poor correlation with the mean AFP, the degree of myelination and the NDT scores. There was, however, a significant correlation between the mean AFP and the degree of myelination (r = 0.67) and also between the mean AFP and the NDT scores (r = 0.70). Longer-term follow-up (mean = 27 months) showed a significant correlation between the early progress of myelination and later developmental level (r = 0.78). Most of the children with a severely delayed myelination, preoperatively, showed a recovery of myelination following CSF drainage. It was concluded that: (1) raised ICP is related to developmental outcome, through the process of myelination; (2) the delay in myelination can be (partially) reversible; and (3) CSF volume is of minor importance regarding neurodevelopment.
Brain↗
Symptomatic carotid artery occlusion. A reappraisal of hemodynamic factors.
BACKGROUND: Over the last several years evidence has accumulated that in addition to embolism, a compromised cerebral blood flow may play an important role in causing transient ischemic attacks and ischemic stroke in patients with occlusion of the internal carotid artery. This evidence is found in both clinical features and ancillary investigations, particularly measurements of cerebral blood flow. SUMMARY OF REVIEW: On the basis of 20 follow-up studies in patients with transient ischemic attacks or minor ischemic stroke associated with an occluded carotid artery, the annual risk of stroke was 5.5% (95% confidence interval [CI], 5.0% to 6.0%), and that of ipsilateral stroke (distinguished in 11 of the 20 studies) was 2.1% (95% CI, 1.6% to 2.8%). Patients with a compromised cerebral blood flow as measured by positron emission tomography, single-photon emission CT, transcranial Doppler, or stable xenon CT (six studies) have an even higher annual risk of stroke (all strokes: 12.5%; 95% CI, 8.9% to 17.6%; ipsilateral stroke: 9.5%; 95% CI, 6.4% to 14.0%). CONCLUSIONS: Because a compromised cerebral blood flow may be an important causal factor in patients with symptomatic carotid artery occlusion, medical and surgical options for treatment are reviewed in this light.
Arterial Occlusive Diseases↗
Status of the neonatal rat brain after NMDA-induced excitotoxic injury as measured by MRI, MRS and metabolic imaging.
Intrastriatal injection of the excitotoxin N-methyl-D-aspartate (NMDA) in neonatal rat brain resulted in an acute ipsilateral decrease of the apparent diffusion coefficient (ADC) of brain tissue water, as measured with diffusion-weighted MRI. The early diffusion changes were accompanied by only mild changes in the overall metabolic status as measured by in vivo 1H MRS and 31P MRS and metabolic imaging of brain sections. Minimal decreases in the high-energy phosphate levels and a small hemispheric acidosis were observed in the first 6 h after NMDA administration. In addition, there was very modest lactate accumulation. Twenty-four hours after the induction of the excitotoxic injury the tissue energy status was still only moderately affected, whereas an overall decrease of 1H MRS-detected brain metabolites was found. Treatment with the non-competitive NMDA-antagonist MK-801 given within 90 min after NMDA injection rapidly reversed the NMDA-induced changes in the entire ipsilateral hemisphere. The effect of the competitive NMDA-antagonist D-CPPene was restricted to the cortical areas and was accomplished on a slower time scale. Our results indicate that; (i) early excitotoxicity in the neonatal rat brain does not lead to profound changes in the metabolic status; and (ii) brain tissue water ADC changes are not necessarily associated with a metabolic energy failure.
Animals↗
Diffusion of metabolites in normal and ischemic rat brain measured by localized 1H MRS.
The apparent diffusion coefficient (ADC) of choline-containing compounds (Cho), creatine and phosphocreatine (Cre), N-acetyl-aspartate (NAA), lactate, and water was measured in normal rat brain, and in the ischemic and contralateral region of rat brain approximately 3 and 24 h after induction of focal cerebral ischemia. After 3 h of ischemia, the ADC of Cre and NAA in the ischemic region had significantly decreased by 29% and 19%, respectively (P < 0.05). Lactate ADC was also obtained in the ischemic region. After 24 h of focal ischemia, no ADC values could be measured for NAA, Cre and Cho in the ischemic region because their concentrations had become too low. The ADCs of lactate and water in the ischemic volume were virtually identical at 3 and 24 h after occlusion. The experiments suggest that the ADC decrease of water after induction of ischemia is partly caused by changes in the diffusion characteristics of the intracellular compartment.
Animals↗
Cisplatin-induced autonomic neuropathy: does it really exist?
The neurotoxic side-effects of cisplatin affect predominantly the large, myelinated fibres of peripheral nerves, leading to a sensory neuropathy. Several reports of cisplatin-associated autonomic neuropathy have been published. Autonomic dysfunction however, is caused by a neuropathy of small unmyelinated nerve fibres. By using the absolute pupil diameter as a parameter of autonomic nervous system function, we studied autonomic neuropathy in the eye of cisplatin-intoxicated rats. In addition, we examined autonomic cardiovascular function by measuring the change in heart rate (HR) and mean arterial blood pressure (MAP) in response to intravenous phenylephrine (PHE) and tyramine (TYR). No significant differences in mean pupil diameter developed in cisplatin-intoxicated rats (n = 12) in the course of 9 weeks (total cumulative dose cisplatin 18 mg/kg) compared with normal controls (n = 9) MANOVA, F1,19 = 0.88, P < 0.36). The PHE- and TYR-induced changes in MAP and HR were virtually the same in cisplatin-intoxicated rats when compared with normal controls. We conclude that cisplatin probably does not cause autonomic dysfunction, at least not in rats, in doses commonly used and which are known to cause a peripheral sensory neuropathy.
Analysis of Variance↗
Relationship between anterior fontanelle pressure measurements and clinical signs in infantile hydrocephalus.
The treatment of choice in progressive hydrocephalus is drainage of cerebrospinal fluid in order to reduce elevated intracranial pressure (ICP). Defining the right moment for surgical intervention, however, in a hydrocephalic infant on the basis of clinical signs alone can be a difficult task. Clinical signs of raised ICP are known to be unreliable and sometimes even misleading. In the present study, the relationship between long-term anterior fontanelle pressure (AFP) measurements and clinical signs was investigated in 37 infants with hydrocephalus. The decision as to whether to operate or not was based on clinical signs alone; AFP values were not taken into account. There was an overall difference between the non-operated group and the preoperative measurements in the operated group, and also between the preoperative and the postoperative measurements in the latter, in regard to both AFP measurements and clinical signs. Almost all preoperative AFP values were increased. The direct correlation (phi) between most individual clinical signs and AFP levels, however, was low (phi = 0.15-0.41). The clinical sign "tense fontanelle" showed the best correlation with the AFP levels (phi = 0.75). Furthermore, using logistic regression analysis, no combination of clinical signs could be found which reliably predicted the AFP. The relationship between the AFP pressure variables and clinical signs was also examined. The pathological A-waves occurred only in the presence of raised (baseline) AFP, a situation in which considerably more frequent B-waves were observed as well. It was concluded that clinical signs of raised ICP in infantile hydrocephalus are not very reliable and AFP monitoring can therefore provide valuable information on intracranial dynamics in patients with dubious neurological manifestations of progressive hydrocephalus.
Female↗
Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device ("Octopus").
OBJECTIVE: This study assessed the feasibility of coronary artery bypass grafting on the beating heart without interruption of native coronary blood flow using a novel anastomosis site restraining device. BACKGROUND: Recently, an end-to-side bypass technique was described that does not require interruption of flow in the recipient artery. METHODS: By means of a suction device ("Octopus"), in 31 pigs the epicardium was grasped and immobilized through an arm contraption fixed to the operating table. In the first 15 consecutive pigs (study I), the two-dimensional motion of an epicardial beacon was monitored. In 16 subsequent pigs (study II), an internal mammary artery was grafted under the microscope in two steps to a proximal coronary artery segment, without cardiopulmonary bypass. First, the internal mammary artery was sutured end-to-side to the outside of the coronary artery. Secondly, an orifice was punched in the partitioning coronary wall by an excimer laser catheter introduced through a temporary side-branch of the internal mammary artery. RESULTS: Study II: During 43 suction periods in four anastomosis areas, immobilization was achieved for 15 to 169 min (>30 h in total) in 13 open- and 9 closed-chest procedures without hemodynamic deterioration. The area circumscribed by the edges of the beacon trajectory (area in which the anastomosis is to be tracked) was reduced from 73.0 +/- 43.0 mm(2) (mean +/- SD) to 1.3 +/- 0.5 mm(2) (p<0.001) in the open-chest and to 0.2 +/- 0.2 mm(2) in the closed-chest procedure. At 6 weeks, no myocardial or coronary suction lesions were found. Study II: Nonocclusive anastomosis surgery required 25 +/- 3 min. No leakage, serious arrhythmias, graft closure or hemodynamic deterioration occurred during the procedure or for 2 h after ligating the coronary artery proximally. At 6 weeks, all seven grafts were patent. CONCLUSIONS: Coronary bypass on the beating heart without interruption of coronary flow is feasible. In both open- and in closed-chest procedures, the "Octopus" reduced anastomosis site motion to about 1 X 1 mm without adverse consequences.
Anesthesia, General↗
The modified excimer laser-assisted high-flow bypass operation.
BACKGROUND: To make high-flow revascularization of the brain possible, we developed an anastomosis technique that obviates temporary occlusion of the recipient artery. After connecting donor and recipient vessels, an Excimer laser catheter, introduced by way of an artificial side branch, creates a hole at the anastomosis site. Because of the inconsistency of the diameter of the hole produced by the closed laser tip, we developed an extensive modification of the procedure. METHODS: A new type of laser tip was developed, consisting of two layers of 60 mu laser fibers in a circular configuration with a diameter of 2.2 mm. The laser tip is fixed to the vessel wall at the anastomosis site by suction with a high-vacuum suction device, and a round piece of recipient vessel wall inside the anastomosis is cut out. RESULTS: Using the aorta as the recipient vessel in 30 rabbits, the modified technique was developed and, in the end, produced anastomoses with a high patency rate. In 25 patients, high-flow bypasses for different indications were made using a venous transplant interposed between the external carotid artery or one of its branches and the intracranial internal carotid artery, utilizing the modified Excimer laser technique for the intracranial anastomosis. Complications related to the new anastomosis technique were minimal, and a satisfactory patency rate was obtained. CONCLUSIONS: The modified Excimer laser-assisted anastomosis technique makes high-flow revascularization of the brain a safe procedure, since temporary occlusion of the recipient proximal brain artery during the making of the anastomosis is obviated.
Anastomosis, Surgical↗
Neural influences on the iris of diabetic rats and effect of oculomotor nerve crush.
Using an animal model where the pupil diameter of the eye in anaesthetized and dark-adapted rats serves as a parameter of autonomic function, we studied the functional recovery of the parasympathetic nerve fibres in the oculomotor nerve after a crush lesion in rats with streptozotocin-induced diabetes compared with normal controls. Prior to the crush lesion, diabetic rats develop significantly (P < 0.001) smaller pupils compared with controls, and this occurs early in the course of the diabetes mellitus. As the difference in pupil diameter between control and diabetic rats persists immediately after the crush lesion, when the nervous control of the pupil is entirely due to sympathetic nerves, we suggest that the reduction in pupil diameter is due to a sympathetic neuropathy. Furthermore, we show that the functional recovery of the parasympathetic input to the iris after a crush lesion of the oculomotor nerve is not as good in diabetic rats as it is in normal control rats.
Animals↗
Beneficial effect of an ACTH4-9 analogue on experimentally induced diabetic autonomic neuropathy in the eye of the rat under general anaesthesia.
While peripheral polyneuropathy is a well-known complication in diabetes mellitus, and the subject of a great deal of study, the clinical importance of autonomic diabetic neuropathy is increasingly recognised. Using an animal model, where the pupil diameter of the eye serves as a parameter of autonomic function, we produced an age and weight curve of pupil diameter and studied the development of autonomic neuropathy in rats with streptozotocin-induced diabetes. We show that diabetic rats develop significantly (P < 0.009) smaller pupils compared with controls, most probably due to a defective sympathetic input, caused by sympathetic neuropathy. Treatment with the neurotrophic peptide Org 2766, a synthetic ACTH4-9 analogue, prevents the occurrence of this sympathetic neuropathy, as the pupil diameters in the ACTH4-9 analogue-treated group are significantly (P < 0.05) larger than the pupils of placebo-treated rats, and are comparable to the pupil diameters of the rats in the control group.
Adrenocorticotropic Hormone↗
T1 and T2 relaxation times of the major 1H-containing metabolites in rat brain after focal ischemia.
The relaxation properties of water and metabolites were measured in rat brain following the occlusion of the middle cerebral artery (MCA) with localized 1H MRS. The PRESS sequence was employed to select volumes of 39 microL in the ischemic and the contralateral hemisphere. T1 and T2 relaxation times and peak intensities of water, choline containing compounds (Cho), creatine and phosphocreatine (Cre) and N-acetyl aspartate (NAA) in both hemispheres were determined at 3-6 h, 1 day and 3 or 4 days after occlusion. Lactate in the ischemic hemisphere was also quantified. The relaxation properties and peak intensities of NAA, Cre and Cho remained unchanged in the ischemic volume during the first 3-6 h of ischemia as compared to the contralateral volume. Water T2 was slightly increased in the ischemic volume. After 24 h the T1 and T2 of water and Cre and the T1 of Cho had increased significantly in the ischemic volume, while the peak intensities of Cho, Cre and NAA were reduced. It appears therefore that tissue changes which occur in the early phase of ischemia have no significant effects on the relaxation behaviour of the metabolites. However, ischemic brain damage affects the relaxation behaviour and concentration of the metabolites and water at later stages.
Animals↗
Non-invasive ICP monitoring in infants: the Rotterdam Teletransducer revisited.
Measurement of intracranial pressure (ICP) is important in patients at risk of raised ICP, as in hydrocephalus. Ideally, it should be non-invasive, thus avoiding the risk of infection and other complications: Such is provided by measurement of ICP through the anterior fontanelle. There are several methods of measuring anterior fontanelle pressure (AFP); those most frequently used are based on the applanation principle. An evaluation of AFP measurement devices resulted in the choice of the Rotterdam Teletransducer (RTT) to be used in our study of children with hydrocephalus. The literature contains little information on the accuracy or validation of the AFP measurements using the RTT. Therefore, the physical qualities of the RTT were reassessed, using a specially developed calibration device. The results of this study demonstrate that membrane temperature does not have any effect on the measured pressure. The thermal stabilization time of the RTT was found to be 3 h after switching on. Insufficient thermal stabilization results in a pressure underestimation of up to 3 mmHg. Furthermore, a maximum inaccuracy of 2.6 mmHg, after calibration and readjustment of the transducer, was calculated. Validation of the equipment was achieved by simultaneous AFP/ICP measurements in hydrocephalic patients showing high correlations (r = 0.96-0.98). The discussion suggests a measurement protocol as a means of increasing the reliability of RTT measurements.
Calibration↗
Value of transcranial Doppler indices in predicting raised ICP in infantile hydrocephalus. A study with review of the literature.
Cerebral hemodynamic changes in infants with progressive hydrocephalus have been studied with the transcranial Doppler (TCD) technique. Several authors have referred to the correlation between the hemodynamic changes and increased intracranial pressure (ICP). Despite conflicting conclusions on the value of pulsatility index (PI) and resistance index (RI) measurements for monitoring infantile hydrocephalus, these pulsatility indices are the most commonly used for this purpose. Although clinical signs of raised ICP are highly variable and unreliable in infants, assumptions have been made in most of the studies about the presence of elevated ICP on the basis of the patient's clinical state. Few studies have reported on actual ICP values, however, and a direct relationship between ICP and TCD changes has never been adequately demonstrated. In the present study, this relationship was investigated in long-term simultaneous TCD/ICP measurements, in an attempt to develop a noninvasive method of monitoring the effect of ICP on intracranial hemodynamics. Two groups of data sets were established. Group I consisted of pre- and postoperative (shunt implantation) TCD/ICP measurements. Group II were long-term simultaneous TCD/ICP recordings showing significant ICP variations. In most of the postoperative measurements there was a decrease in the average PI and RI values. The correlation between PI or RI and ICP in the long-term simultaneous recordings, however, was generally poor. The risk of obtaining false positive or false negative PI or RI values in short-term measurements was also demonstrated. It can be concluded from our results, besides the wide range of reference values for the Doppler indices and extracranial influences upon them, that the present Doppler indices are inadequate for monitoring the complex intracranial dynamic responses in patients with raised ICP.
Adolescent↗