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Biomedical subjects

M Brock

Publications and source records attributed to M Brock.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Intraoperative contrast echocardiography for detection of a patient foramen ovale using a provocation test and ventilation with PEEP respiration].

UNLABELLED: Intraoperative paradoxical air embolism may occur even if a patent foramen ovale (PFO) is excluded by contrast transoesophageal echocardiography (TEE) under 20 cm H2O positive airway pressure. It is questionable whether the combination of PEEP and ventilation with a large tidal volume increases the sensitivity of contrast TEE in detecting a PFO. METHODS: Eighty healthy patients (ASA status I, II) scheduled for surgery in the supine position and ranging from 25 to 72 years of age were investigated by TEE, which was performed in the biatrial viewing mode (short axis). Echocardiographic contrast (10 ml agitated gelatine solution) was injected during two different ventilation manoeuvres. Manoeuvre I: Contrast injection during the application of 20 cm H2O positive airway pressure for 5 s. The pressure was released when the right atrium became completely opacified by echo targets. The injected bolus was observed throughout the ventilatory cycle, with special attention being given to early expiration and systole. A right-to-left shunt was assumed if five echo targets were observed in the left atrium. Manoeuvre II: Contrast injection during ventilation with PEEP (15 cm H2O), a tidal volume of 1,200 ml, and a respiratory rate of 6/min. RESULTS: The frequency of a PFO causing a right-to-left interatrial shunt was 8.7% (7 cases) in manoeuvre I and 15% (12 cases) in manoeuvre II. In one case a PFO was diagnosed intraoperatively by chance. DISCUSSION: The use of provocation manoeuvres including ventilation with PEEP and high tidal volumes might improve the ability to detect a PFO presenting with right-to-left interatrial shunt by intraoperative contrast TEE, but does not have 100% sensitivity. However, our results clearly indicate that ventilation with PEEP and high tidal volumes may predispose to paradoxical embolism.

Adult↗
PubMed1996

[Isolated idiopathic syringobulbia: case report and summary of the literature].

Syringobulbia is an uncommon lesion of the central nervous system. It is defined as a pathological cavitation of the brain stem. The most common symptoms are headache, vertigo, dysphonia or dysarthria, trigeminal paraesthesia, dysphagia, diplopia, tinnitus, palatal palsy. Syringobulbia occurs with atlantoaxial congenital abnormalities (Chiari malformation), infection, tumours, and other causes. The idiopathic syringobulbia is however a rare finding. Early surgical treatment is the treatment of choice. We report on a 58-year old female patient with idiopathic syringobulbia. She complained of occipital headaches and vertigo. On examination she had horizontal nystagmus and diplopia. Occipital headaches and vertigo were improved after operation. We review the literature on syringobulbia, and discuss the clinical features of this uncommon condition.

Brain Stem↗
PubMed1995

Influence of aneurysm location on the development of chronic hydrocephalus following SAH.

The incidence of chronic hydrocephalus was analysed in a series of 204 patients with aneurysmal subarachnoid haemorrhage (SAH). Its development was significantly related to the quantity of subarachnoid blood, but even more to the location of the haemorrhage and to the aneurysm site. Hydrocephalus was more frequent in patients under poor initial condition. Whereas intracerebral haemorrhage did not increase the risk of chronic cerebrospinal fluid (CSF) resorption disturbances. Patients with intraventricular haemorrhage or voluminous haemorrhage in the basal cisterns have a significantly higher risk of such a complication. In this series 30 (15%) patients developed chronic hydrocephalus and required shunting. Surprisingly, in our series a shunt was never needed in patients with aneurysms of the middle cerebral artery (MCA). SAH from an aneurysm of the internal carotid artery (ICA) also never caused a shunt-dependent hydrocephalus except in cases with accompanying intraventricular haemorrhage. The percentage of chronic hydrocephalus was relatively high (19%) in patients with anterior communicating artery (ACoA) aneurysms but definitely highest in patients with an aneurysm of the vertebrobasilar (VB) system (53%).

Adult↗
PubMed1995

Modern management of spinal and spinal cord vascular lesions.

Spinal arteriovenous shunts affect all age groups from neonates to the elderly in connection with different entities. The authors present 7 illustrative cases of spinal and spinal cord vascular lesions with different etiology, angioarchitecture, symptoms, risks, and prognosis, but similar pathophysiology: spinal cord AVM, multifocal AVM with venous impairment, paraspinal arteriovenous fistulas in children, spinal dural AV fistula, and an arteriovenous malformation of the filum terminale. Therapy was consistent and demonstrated the benefit of combined treatment. Specific endovascular embolisation with a permanent liquid substance (NBCA) is the method of choice. In 5 of the 7 patients, the malformation was completely occluded in one therapeutic session. Two patients needed additional embolisation. Systemic or neurological symptoms improved or regressed completely in all cases. No patient has had more than 3 sessions of endovascular approach. The filum terminale AVM was treated by direct surgery due to the risks of endovascular approach. As shown by our observations, venous flow in the intrinsic network of the spinal cord is highly sensitive to hemodynamic changes. Thus, the hemodynamic balance must be maintained to obtain stable embolisation results, particularly if a considerable size reduction of the AV shunt has been achieved.

Adolescent↗
PubMed1995

[Bilateral carpal tunnel syndrome--surgical therapy--prognostic factors and results].

Patients submitted to bilateral section of the transverse carpal ligament suffer from predisposing diseases, hormonal alterations or have wrists exposed to increased occupational strain more frequently than patients with unilateral carpal tunnel syndrome. In addition, in this group of patients the results of neurophysiological tests are more markedly pathologic. The good initial operative results are frequently followed by a relapse of symptoms. There is no appreciable difference between the operative results for the right versus for the left hand nor between the hand operated on in the first versus in the second place. A long-term improvement of opposite side symptoms following the first operation only occurs in exceptional cases.

Adult↗
PubMed1995

[Use of GDC coils in treatment of inoperable aneurysms: report of initial experiences].

The authors report on the endovascular occlusion of intracranial aneurysms with GDC coils in 8 patients. In 2 cases, the diagnosis was made because of subarachnoidal hemorrhage. Three patients complained about headache, and one patient had an oculomotor palsy. The findings were incidental in 2 cases. Angiography demonstrated an aneurysm of the internal carotid artery in 4 of the 6 females and in the 2 males (mean age 50 years) and a basilar artery aneurysm in 4 cases. The indication for endovascular treatment was established after carefully weighing the risks against those of a neurosurgical intervention. It was possible to occlude completely the aneurysm by induced electrothrombosis and to preserve the patency of the main vessel in all cases. One female (case 6) developed a hemiparesis due to embolism of a medial branch six hours after treatment. This receded completely after thrombolysis with urokinase. A second patient showed further growth of the internal carotid aneurysm on the control angiogram obtained after six months. Our initial results are encouraging. With increasing experience, endovascular treatment is expected to become the method of choice for the treatment of most inoperable cerebral aneurysms.

Adult↗
PubMed1994

[Intraspinal neurinoma in the thoracolumbar junction presenting unusual symptoms. The differential diagnosis of lumbago].

After more than a year of persistent lumbosacral pain a 53-year-old woman suddenly developed unilateral monoradicular pain over the S1 dermatome. Neurological, general medical and biochemical examinations were unremarkable, but myelography and magnetic resonance imaging revealed a cystic intraspinal space-occupying lesion at the level of L1, which was completely excised surgically. It proved to be a neurinoma, 5 x 3 x 3 cm, completely filling the spinal canal at the junction between the conus medullaris and the cauda equinus. The patient was without symptoms and neurological deficit after the operation. The tumour having been completely removed, the prognosis is good.

Diagnosis, Differential↗
PubMed1994

Response of multicellular tumor spheroids to liposomes containing TNF-alpha.

This publication describes a new model to investigate the influence of tumor necrosis factor-alpha (TNF-alpha) on a three-dimensional glial cell aggregate under defined, standardized, reproducible conditions using the glioma cell line A 172. The cells are initially grown as normal monolayer culture until they reach a cell density of up to 1 x 10(6). Subsequently they are grown as spheroids by the liquid overlay technique. Spheroids grown in this way were divided into ten groups of more than 50 cell aggregates. Three groups were coincubated with free TNF-alpha in increasing dosages (100 ng/ml, 200 ng/ml and 1000 ng/ml); three groups were incubated with empty liposomes (0.2 mg/ml, 0.4 mg/ml and 2 mg/ml); three groups received liposomes which had been loaded with TNF-alpha, and one group, which received no treatment, served as control. The diameter of the spheroids ranged from 80 microns to 350 microns. There was no significant difference in growth between the 3 groups treated with 'free' TNF-alpha. Comparing spheroids treated with TNF-alpha with those which had been coincubated with empty liposomes, there was a significant difference (p < 0.001) in growth, which correlated with the amount of liposomes. Similarly, free TNF-alpha had a significantly (P < 0.001) stronger growth-inhibiting effect as compared to liposomes loaded with TNF-alpha. Comparing the groups treated with liposomes only to those treated with liposomes loaded with TNF-alpha, the latter exhibited a more marked (although not significantly) growth-inhibiting effect. The preliminary conclusion is that the major growth-inhibiting effect seems to be mediated by the liposomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Aggregation↗
PubMed1994

Venous and paradoxical air embolism in the sitting position. A prospective study with transoesophageal echocardiography.

This prospective study investigates the frequency of patent foramen ovale (PFO), venous air embolism (VAE) and paradoxical air embolism (PAE) by transoesophageal echocardiography (TOE) in neurosurgical patients operated on in the sitting position. The risk of PAE after exclusion of PFO is assessed. A PFO was identified by pre-operative TOE and VAE and PAE by continuous intraoperative TOE. Sixty-two patients were divided into two groups, 22 patients were studied in group 1 (posterior fossa surgery) and group 2 (cervical surgery) contained 40 patients. Pre-operative TOE demonstrated a PFO in 5 of the 22 patients in group 1 (23%). Patients with proven PFO were excluded from the sitting position. Two further patients of this group (12% of 17 patients), in whom a PFO had been excluded pre-operatively, nevertheless had PAE, air occurring in all cavities of the heart. In group 2 the incidence of PFO was 4 out of 40 patients (10%). No PAE was observed in this group. Three morphological types of VAE with different haemodynamic and ventilation changes were demonstrated. VAE was observed in 76% of all posterior fossa operations and in 25% of cervical laminectomies. We conclude that a pre-operative search for PFO is mandatory considering its incidence of 23% in group 1 and of 10% in group 2, and the risk of PAE. If a PFO is detected, the sitting position should be avoided. A residual risk for PAE remains despite exclusion of PFO because the reliability of TOE is limited. TOE is the method of choice for detecting VAE and PAE.

Adult↗
PubMed1994

Postnatal changes in cochlear polyamine metabolism in the rat.

Ornithine decarboxylase (ODC), the initial enzyme in the polyamine biosynthetic pathway, is increased in the developing rat cochlea, suggesting that polyamine biosynthesis is important in cochlear development. Although cochlear polyamines have been detected in adult rats, they have not been identified in developing rats. We quantified polyamines in the developing and mature rat cochlea and further characterized ODC in the early postnatal period. Putrescine and spermidine in combined tissues of the organ of Corti and lateral wall of the cochlea were highest during the first 10 postnatal days, then declined to adult levels shortly thereafter. Spermine demonstrated a similar developmental trend. A high spermidine to spermine ratio was noted during this period as was rapidly increasing ODC activity. A high spermidine/spermine ratio was also noted in the cochlear nerve of developing and mature rats, suggesting that spermidine may be necessary for function and maintenance of the nerve. This is the first report of polyamines in the developing rat cochlea. The period of increased polyamine synthesis coincides with the critical period for ototoxicity induced by alpha-difluoromethylornithine, a specific ODC inhibitor, and the period of rapid cochlear development.

Analysis of Variance↗
PubMed1994

[The "Neuropsychological Screening Test (NST)": initial validation and reliability studies].

Medical examinations only insufficiently measure cognitive impairment in neurological and neurosurgical patients. Due to costs an personnel shortages, adequate neuropsychological test methods are typically bypassed. Indeed, the very size and methodological problems of current tests impede their application in clinical practice. To resolve this dissatisfying state of affairs, we have developed a standardized, scored form of initial neuropsychological examination. The Neuropsychological Screening Test (NST) comprises 45 items, is easy to handle, and can be conducted in 15-20 min. The NST measures psychic performance along functional parameters such as orientation in place and time, primary and secondary language, visuospatial ability, attention, and memory skills. We have assessed the validity and reliability of the NST in a prospective study. 129 neurosurgical patients (60% malignant or benign cerebral tumors, 21% vascular malformations with and without subarachnoid hemorrhage, 6% traumatic brain injury, 3% hydrocephalus, 10% others) and 52 control subjects were included in the study. The difference in average total NST-scores was highly significant for the two groups (t = -7.84, DF = 177.93, p < .001). In addition, two chronologically separate subsamples of NCH patients (N = 81) and controls (N = 35) were tested using the Mini-Mental State (MMS). The correlation between total NST-score and MMS results was r = .49 (p < .001). Cross-tabulation was used to set a cut-off score, by means of which 80% of the neurosurgical patients were identified as true positive and 74% of the controls as true negative. A 24-hour retest confirmed the NST as reliable to .85 (p < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Emergency drainage of acute intracranial hematomas with unsterile conditions during computerized tomography].

From January 1979 to December 1993, we treated 761 patients with epidural (n = 184) or subdural (n = 577) haematomas. Twenty-six were subjected to emergency trepanation on the CT-table, since their condition was considered life-threatening. All fulfilled the following criteria: 1. Glasgow Coma Score below 9, 2. Progressive coma and/or progressive anisocoria and/or 3. Other signs of acute life risk correlating with an intracranial haematoma. Nine of these 26 patients died (3 out of a total of 17 with epidural and 6 out of a total of 9 subdural haematomas). In 5 cases the cause of death was brainedema, in 3 cases a multiorgan failure, and one pneumonia. None of the patients acquired an infection at the trepanationsite or elsewhere within the CNS. Twelve patients had postoperative complications (8 with epidural and 4 with subdural haematoma). These caused a prolongation of the average hospitalization period. Patients with uncomplicated follow-up were discharged after 17.6 +/- 4.2 days, as opposed to 44.8 +/- 15.7 days for complicated cases. Six months following discharge 8 of 17 patients with an epidural haematoma had reached stage 5 of the Glasgow Outcome Scale, 4 were in stage 4, 1 in stage 3, and 1 in stage 2. Three patients had died. None of the 9 patients with a subdural haematoma had reached stage 5. One patient had reached stage 4, 2 stage 2, while 6 patients had died.

Adolescent↗
PubMed1994

[A case of diastematomyelia (split cord malformation type I) with clinical manifestation in adulthood].

We present the case of a female patient with split-cord malformation type I (diastematomyelia) who developed first symptoms as an adult and worsened markedly after intramedullary injection of local anaesthetics. Our own observations are compared with the small number of cases known from the literature. We are using the morphological and clinical classification of spinal malformations of Pang et al. (1992), which is based on a uniform disturbed embryonal development [18, 19]. The 52-year-old patient presented to her family physician in September 1991 with pain in the region of the vertebral column which had developed gradually over a period of two weeks. Following unsuccessful analgetic and muscle-relaxing therapy, the family physician had the patient transferred to the orthopedic department of a hospital. Lumbar peridural infiltrations were carried out there in February 1992 for a suspected disc prolapse. Since June 1992, she had no longer been able to walk. In addition, there had also been a progredient urinary incontinence since April 1992. The spinal CT scan reveals a duplication of spinal cord starting at the level of L4 as well as a bony spur dividing the spinal cord at levels L4 and L5. MRI of the vertebral column likewise reveals a duplication of the spinal cord starting at L4 as well as a low conus and a bone spur extending from L4 to L5 is also visualized here. Each primordial spinal cord is surrounded by its own dura mater. Altogether, this led to the diagnosis of split cord malformation type I according to Pang et al. [18].(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

[Considerations of subjective and interpersonal factors in physical and social prognosis after severe craniocerebral trauma with prolonged coma. Observation of an individual outcome after 11 years].

The prognosis following severe craniocerebral trauma is affected by a broad variety of factors. Based on an individual fate 11 years post craniocerebral trauma with persistent coma, some thoughts are presented concerning relevance of subjective and interpersonal factors for the patient's vital and social prognosis and discussed in light of the social energy concept posited by the Dynamic Psychiatry school.

Activities of Daily Living↗