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Biomedical subjects

B Rydenhag

Publications and source records attributed to B Rydenhag.

At least 19 recordsLinked to original sources
PubMed2005

Outcome after severe brain damage, what makes the difference?

OBJECTIVE: To assess and compare the consequences for outcome in terms of the dimensions of activity and participation for two groups: group A, which received early formalized rehabilitation, and group B, which received late or no formalized rehabilitation. RESEARCH DESIGN: A cross-sectional study. PROCEDURE: Twenty-six patients (A: n = 14 and B: n = 12) with severe brain damage were included. The participants were assessed a mean of 26.6 months (SD 7.1, median 25, range 14-41) after the incident using the structured form for the Swedish Neuro database, the Glasgow Outcome Scale (GOS), the Extended Glasgow Outcome Scale (GOSE) and the Functional Independence Measure (FIM). RESULTS: The study reveals a better outcome for group A. No patient remained in a vegetative state in group A as compared with three in group B. In group A, 50% were independent as compared with 17% in group B. The frequency of return to work was 43% in group A, but no patient in group B had returned to work.

Activities of Daily Living↗
PubMed2005

Parenchymal lesions in pharmacoresistant temporal lobe epilepsy: dual and multiple pathology.

OBJECTIVES: Dual pathology is reported in 5-30% of temporal lobe resections performed in pharmacoresistant epilepsy. Dual pathology may be of importance for surgical planning and also for the understanding of the pathogenesis of epilepsy. We describe the frequency of dual or multiple pathology, i.e. more than one histopathological diagnosis, in adults with temporal lobe resections. MATERIAL AND METHODS: Surgical specimens from 33 consecutive patients with resections including mesial as well as neocortical temporal structures were reviewed. All histopathological findings were recorded. Post-mortem specimens from 11 control subjects were also reviewed. RESULTS: Dual or multiple pathology was found in almost half of the epilepsy patients (48%). Hippocampal sclerosis was found in 25 patients (76%), malformations of cortical development in 15 (46%), of which 12 (36%) were microdysgenesis, and low-grade tumours in seven (21%). Apart from mild gliosis, there were no histopathological changes in the control specimens. CONCLUSION: Dual or multiple pathology was a common finding in this group of adults with temporal lobe resections. In order to increase our understanding of how aetiological factors may combine in the development of seizures, we consider it relevant and important to report all histopathological findings in epilepsy surgery series.

Adult↗
PubMed2004

Herpesviral DNA in brain tissue from patients with temporal lobe epilepsy.

OBJECTIVES: Presence of DNA from six herpesviruses were examined in brain tissue from patients operated for temporal lobe epilepsy. MATERIAL AND METHODS: A total of 19 Canadian patients (I) with a median age of 22 years, 17 Swedish patients (II) with a median age of 14 years and a reference group comprising 12 individuals were studied. Presence of herpesviral DNA was detected by nested polymerase chain reaction. RESULTS: Of three children with Rasmussen's encephalitis, Cytomegalovirus (CMV) DNA was found in two, and human herpesvirus type 6 DNA in two. In six children with ganglioglioma, Epstein-Barr virus (EBV) was detected in four. CMV DNA was found significantly more in group I compared with II, while the reverse occurred with EBV DNA. Malformations of cortical development were found significantly more in group II compared with I. CONCLUSION: Detection of DNA from some herpesviruses in epileptic brain tissue may possibly be associated with distinct clinical conditions, but factors such as age and malformations of cortical development should also be considered.

Adolescent↗
PubMed2004

Visual field defects after temporal lobectomy -- comparing methods and analysing resection size.

OBJECTIVES: The frequency of visual field defects (VFD) after temporal lobe resections (TLR) was compared for two types of TLR and VFD frequency was correlated to resection size. METHODS: Pre- and post-operative perimetry results were analysed for 50 patients with TLR for medically intractable epilepsy. Thirty-three patients had a classical TLR and 17 had a TLR with less lateral extension. Post-operative MRIs were studied in 34 patients by scoring resection size in 12 compartments in the temporal lobe. RESULTS: Twenty-five patients developed a VFD. In the classical TLR group, 16 of 33 developed a VFD, compared with nine of 17 in the other group. The resection points were higher for the VFD group in the most anterior compartment studied, in the superior temporal gyrus. CONCLUSIONS: There was no clearcut difference in VFD frequency between the surgical methods studied. However, the compartmentalized analysis disclosed a relation between the extent of resection in the anterior part of the superior temporal gyrus and VFD frequency.

Adolescent↗
PubMed2002

Widespread microdysgenesis in therapy-resistant epilepsy--a case report on post-mortem findings.

Microdysgenesis is a subtle malformation, which is often found in specimens from epilepsy surgery. It is, however, not clear whether the changes are focal or diffuse. A recent autopsy case offered an opportunity to investigate whether microdysgenesis found after temporal lobe surgery was focal or widespread in the brain. The entire brain of a 20-year-old patient who died suddenly and unexpectedly was examined histologically. Microdysgenesis had previously been diagnosed after a left temporal lobectomy performed because of therapy-resistant seizures. A light microscopic examination was performed on specimens stained with Luxol-fast blue-cresyl violet and polyclonal antibodies to glial fibrillary acidic protein. Widespread microdysgenesis with irregular nerve cell distribution in the cortex and an increased number of nerve cells in cortical layer I and in the white matter was found in the right temporal and parietal lobes and bilaterally in the frontal and occipital lobes. The post-mortem examination confirmed the previous diagnosis of microdysgenesis and showed that the changes were widespread in a patient who was operated on because of focal epilepsy.

Adult↗
PubMed2002

Sympathetic nervous activation following subarachnoid hemorrhage: Influence of intravenous clonidine.

BACKGROUND: Subarachnoid hemorrhage is often accompanied by systemic complications and cerebral vasospasm. Elevated levels of circulating catecholamines may be involved in the pathophysiology behind these events. The alpha-2-agonist clonidine inhibits sympathetic outflow by a central mechanism. Unrestricted sympathoexcitation may be detrimental and administration of clonidine may be beneficial in these patients. METHODS: Using isotope dilution methodology, norepinephrine kinetic determinations, comprising determination of arterial norepinephrine concentration and rates of norepinephrine spillover to and removal, or clearance, from plasma, were performed on three occasions during the first week after subarachnoid hemorrhage in 25 patients. Eleven of these patients received clonidine (continuous i.v. infusion 5.8 +/- 0.7 microg x kg(-1) x 24 h(-1)) and the remainder, standard therapy. Initial results were compared with 17 healthy age-matched subjects and eight patients suffering from severe traumatic brain injury without traumatic subarachnoid hemorrhage. RESULTS: Subarachnoid hemorrhage patients exhibited markedly elevated arterial plasma norepinephrine concentrations [3.74 +/- 0.48, P < 0.001 vs. healthy subjects (1.59 +/- 0.11 nmol/L) and P < 0.05 vs. head trauma patients (1.94 +/- 0.29 nmol/L)]. The rate of clearance of norepinephrine from plasma in the subarachnoid patients was also significantly greater than that observed in the healthy subjects (2.66 +/- 0.15 vs. 2.14 +/- 0.15 L/min, P < 0.05) and the head trauma patients (2.00 +/- 0.12 L/min, P < 0.05). Compared with both control groups, on admission the rate of spillover of norepinephrine to plasma following subarachnoid hemorrhage was markedly elevated (9.11 +/- 1.12, P < 0.001). Clonidine treatment (continuous i.v. infusion 5.8 +/- 0.7 microg x kg(-1) x 24 h(-1)) did not reduce the increased rate of spillover of norepinephrine to plasma following subarachnoid hemorrhage. CONCLUSION: Sympathetic nervous activity is markedly elevated following subarachnoid bleeding. Clonidine had no effect on the rate of norepinephrine spillover to, or clearance from, plasma in these patients. Clearly, further studies are required to elucidate the mechanisms responsible for generating sympathetic nervous activation following subarachnoid hemorrhage.

Adrenergic alpha-Agonists↗
PubMed2001

[Well-integrated chain of care results in better prognosis in severe brain injury].

The result of a project in the western region of Sweden regarding a multi- and interdisciplinary approach to patients with severe traumatic brain injury/subarachnoid bleeding is reported. The importance of early structured intervention and long-range follow-up by a rehabilitation team is stressed. The goal is to afford patients and their families/caregivers optimal care and support from the time of injury through rehabilitation. The project has resulted in an established clinical routine. Results indicate that patients treated in this manner attain a higher level of performance in a shorter period of time. Furthermore, results from one-year post-injury evaluation demonstrate a high degree of Life Satisfaction (Fugl-Meyer questionnaire) for most patients. This is a long-range study which will monitor patients for at least four years.

Brain Injuries↗
PubMed2001

Complications of epilepsy surgery after 654 procedures in Sweden, September 1990-1995: a multicenter study based on the Swedish National Epilepsy Surgery Register.

OBJECTIVE: To present the first national multicenter study on complications after epilepsy surgery procedures to include all epilepsy surgery centers in Sweden: Göteborg, Linköping, Lund, Stockholm, Umeå, and Uppsala. METHODS: Every epilepsy surgery procedure in Sweden is reported to the Swedish National Epilepsy Surgery Register. The report includes relevant social and medical items and complications. A complication is defined as minor if it resolves within 3 months and major if it affects activities of daily living and lasts longer than 3 months. Follow-up data are recorded for 2 years after the operation. Intrinsic checkpoints and external revision validate the register data. RESULTS: During the inclusion period (September 1990-December 1995), 654 surgical procedures were performed (age range, 6 mo-67 yr). Of these, 205 were invasive electrode procedures (182 first investigations and 23 reinvestigations), and 449 were therapeutic procedures (375 first operations and 74 reoperations). After invasive electrode procedures, only minor complications were reported (6.3%). For all 449 therapeutic procedures (including reoperations), minor complications were reported in 8.9% and major complications in 3.1 %. Only one major complication was reported in a patient under the age of 35 years. CONCLUSION: This is the first national multicenter study on complications after epilepsy surgery. It demonstrates that these procedures as performed at six different centers in Sweden are safe, but also that risk is related to age. In patients younger than age 35 years, the risk for a major complication after invasive subdural strip electrode investigation and epilepsy surgery is low.

Adolescent↗
PubMed2000

Increased sympathetic nervous activity in patients with nontraumatic subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Activation of the sympathetic nervous system, which leads to elevation of circulating catecholamines, is implicated in the genesis of cerebral vasospasm and cardiac aberrations after subarachnoid hemorrhage. To this juncture, sympathetic nervous testing has relied on indirect methods only. METHODS: We used an isotope dilution technique to estimate the magnitude and time course of sympathoadrenal activation in 18 subarachnoid patients. RESULTS: Compared with 2 different control groups, the patients with subarachnoid hemorrhage exhibited an approximately 3-fold increase in total-body norepinephrine spillover into plasma within 48 hours after insult (3.2+/-0.3 and 4.2+/-0.7 versus 10.2+/-1.4 nmol/L; P<0.05 versus both). This sympathetic activation persisted throughout the 7- to 10-day examination period and was normalized at the 6-month follow-up visit. CONCLUSIONS: The present study has established that massive sympathetic nervous activation occurs in patients after subarachnoid hemorrhage. This overactivation may relate to the well-known cardiac complications described in subarachnoid hemorrhage.

Adult↗
PubMed1999

Surgical treatment of epilepsy--clinical, radiological and histopathological findings in 139 children and adults.

The present study relates clinical and radiological data to histopathological diagnoses in the first 139 patients (children and adults) in the Göteborg Epilepsy Surgery series. Temporal lobe resections were most common (54.0%) followed by frontal lobe (18.0%) and multilobar resections (11.5%). All histopathological specimens were re-evaluated in connection with this study. Parenchymal malformations and atrophic-gliotic lesions were the most common histopathological findings. Microdysgenesis was more common than major malformations (24.5% versus 11.5%). When the MRI scans were blindly re-evaluated the MRI findings correlated with histopathological diagnosis in all of the vascular malformations, in 77.8% of the tumours, in 76.5% of the cases with hippocampal sclerosis but only in 28.6% of the major cortical development malformations. Hemispherectomies carried the best seizure outcome prognosis followed by temporal lobe resections (75.0% versus 57.3% seizure free 2 years after surgery). Vascular malformations carried the best, and microdysgenesis the worst prognosis (76.9% versus 39.4% seizure free).

Adolescent↗
PubMed1999

Microdysgenesis in surgical specimens from patients with epilepsy: occurrence and clinical correlations.

Malformations of cortical development are commonly associated with epilepsy. In the first 139 consecutive patients in the Göteborg epilepsy surgery series, parenchymal malformations were found in 56. 1% of the children and in 23.1% of the adults. Microdysgenesis (MDG), which was the most common parenchymal malformation, was found in 35. 1% of the children and in 16.7% of the adults. The aim of this study was to identify clinical characteristics of patients with MDG. Mental retardation was found to be significantly more common in patients with major parenchymal malformations and in patients with MDG compared with patients without parenchymal malformations. Patients with major parenchymal malformations as well as patients with MDG also had a significantly earlier onset of seizures than patients without parenchymal malformations, also when adjusting for mental retardation. Patients with MDG were in these clinical aspects shown to closely resemble patients with major malformations. These findings suggest that MDG is a pathoanatomical entity of clinical relevance, with implications both in mental retardation and in epileptogenesis.

Adolescent↗
PubMed1998

A standardized neurosurgical neurointensive therapy directed toward vasogenic edema after severe traumatic brain injury: clinical results.

OBJECTIVE: Analysis of a standardized therapy focusing on prevention and treatment of vasogenic edema in patients suffering severe traumatic brain injury (TBI). DESIGN: A retrospective analysis. SETTING: Neurointensive care unit at Sahlgrenska University Hospital, Göteborg, Sweden. PATIENTS: 38 patients with severe TBI were included. The median Glasgow Coma Score was 5 (range 3-8) and median age 27 years (range 5-70 years). INTERVENTIONS: Measurement of intracranial pressure (ICP). Surgical evacuation of hematomas and contusions. Volume expansion aiming at normovolemia. Sedation with continuous intravenous infusion of low-dose thiopentone and reduction of stress response by clonidine. Normalization of capillary hydrostatic pressure by metoprolol and clonidine. If ICP and cerebral perfusion pressure (CPP) were not stabilized (ICP < 20 mmHg and CPP > 60 mm Hg), a continuous infusion of dihydroergotamine was added. In 4 patients a craniectomy was performed. RESULTS: Of the 38 patients, 27 (71%) survived with good recovery or moderate disability, 5 (13%) survived with severe disability, 1 (3%) remained in a vegetative state, and 5 (13%) died. The mortality due to intracranial hypertension was 11% (4 patients). CONCLUSION: A therapy focusing on treatment of the assumed vasogenic edema in combination with aggressive neurosurgery resulted in an outcome as good as the best previously reported.

Acute Disease↗
PubMed1996

Cortical reorganisation of sensory, motor and language functions due to early cortical damage.

During evaluation of a 22-year-old man for epilepsy surgery it was demonstrated that reorganisation of sensory, motor and language functions had occurred. Restricted perinatal lesions in the left frontal opercular region and in the hand primary sensory area had resulted in severe partial epilepsy and minor neuropsychological deficits, but no neurological deficits. The dominance for language and handedness was shifted to the right hemisphere but some language representation was still found in the left hemisphere. Threshold electrical stimulation via subdurally placed cortical electrodes revealed reorganisation of the hand sensory area in the left hemisphere. Hand sensory responses were electrically evoked close to the opercular region where also face sensory responses were recorded. Some of the sensory responses were located in the frontal lobe in the premotor cortex. The locations of the sensory representation areas differed from those expected neuroanatomically. The cortical motor responses were located around the presumed location of the precentral gyrus. These findings are considered to represent a functional intra- and interhemispherical reorganisation of cortical areas as a result of early cortical lesions, anatomically close to the somatosensory and language areas. A possible mechanism discussed is reorganisation of the thalamocortical projections.

Adult↗
PubMed1996

Effects of prenatal alcohol exposure on activity and learning in Sprague-Dawley rats.

Nulliparous pregnant Sprague-Dawley rats were exposed to ethanol via a liquid diet technique (FAE, fetal alcohol exposure) or administered a fixed amount of control diet from gestational day 11 to day 21. The offspring, at 2-3 months of age, were studied in tests of mechanically monitored motor activity and learning acquisition in an automatized testing cage requiring an instrumental discriminative response, where the ability to learn and relearn correlations of a light signal to water presentation was monitored. A significantly reduced activity (i.e. ramp mounting behaviour) in a novel situation was obtained in the FAE group compared to controls. The initial disruption of ramp mounting behaviour could reflect alterations in either habituation to a novel test situation, altered neophobia, or some retardation in associating these responses with the outcome of water-availability. Adult FAE rats (six months of age) showed a tendency towards a lowered acquisition performance (p = 0.06) when tested in a circular Morris-type swim maze, but no detectable differences were shown in a motor activity test chamber situation.

Aging↗
PubMed1996

High levels of glycine and serine as a cause of the seizure symptoms of cavernous angiomas?

Cavernous angiomas are vascular malformations that cause neurodegeneration and symptoms including epileptiform seizures, headache, and motor deficits. Following neurosurgical removal of the angiomas, patients mostly recover well and become seizure-free. This study reports on the levels of certain amino acids in angiomas, obtained from 13 patients. Distinct zones of the angiomas were analyzed, from the thrombotic core, via gliotic, hemosiderin-infiltrated intermediate zones, to a periphery without macroscopic abnormalities. The neurotransmitter amino acids glutamate, aspartate, and GABA as well as phosphoethanolamine displayed decreasing levels from the periphery to the core, reflecting the gradual neuronal loss. Compared with normal brain tissue, there was a marked increase in the levels of serine (fivefold), glycine (10-fold), and ethanolamine (20-fold) in the peripheral zone of the cavernous angiomas. The results are discussed in relation to seizures and NMDA receptor activation, neuron-glia interactions, membrane phospholipids, and blood-brain barrier function.

Adult↗
PubMed1995

Expression of Ca(2+)-ion permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors in Xenopus oocytes injected with total RNA from human epileptic temporal lobe.

By using the Xenopus oocyte as an expression system, we have performed a series of experiments in order to examine the divalent cation-permeability of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors from the human epileptic temporal lobe. Xenopus oocytes, injected with total RNA from the epileptic temporal lobe, were tested for expression of receptors by a conventional two electrode voltage-clamp technique. Administration of glutamate and AMPA gave small or no clear current responses, whereas kainate produced large inward non-desensitizing currents. The current responses evoked by kainate were concentration dependent. Experimental data gave a Hill coefficient of 1.06 and an EC50 value of 87 microM. The current to voltage relationship showed an inward rectification and when the concentration of divalent cations were enhanced, there was a shift in the reversal potential from -11 mV (2 mM Ca2+) to 12 mV (60 mM Ba2+). This yielded a pBa2+/pK+ permeability ratio of 1.6 when the constant field equation was used. The amplitude of the currents evoked by 600 microM kainate in solutions containing higher Ba(2+)-ion concentrations was markedly diminished (46% in 10 mM Ba(2+)- and 75% in 60 mM Ba(2+)-solution), when compared to those obtained in normal Ringer's solution, suggesting interactions between different cation species and/or screening of surface charges.

Animals↗
PubMed1994

A new operant discrimination test procedure for resident rats.

An automated method for testing visual discrimination with water reinforcement using a modified residential Y-maze is described. The visual stimulus is presented above one of two water holes. Rats have been tested with different lengths of water periods and different intervals between the periods. During the 10 days of testing, overall activity decreased. Activity on the initial days was low during daytime, with few drinking attempts. Discrimination learning acquisition was measured as the increase in the percentage of water periods with drinking attempts in which the first attempt occurred on the correct side, and/or as the increase in the number of correct drinking attempts as a percentage of all drinking attempts. Acquisition was observed both when light indicated water and when it indicated no water. This test model may offer a useful method for standardized measurement of left/right, light on/off discriminations.

Acoustic Stimulation↗