Biomedical subjects
Publications and source records attributed to L Persson.
The levels of ADP-ribosyl transferase (ADPRT) activity following a standardized dose of 100 Gy gamma-radiation have been determined in leukocytes from 12 different mammalian species. Here, we report that the 100 Gy-induced levels of ADPRT correlated in a highly significant manner to the line spans of the mammals.
BACKGROUND AND PURPOSE: Treatment of supratentorial intracerebral hemorrhage (SICH) is still controversial and new adequately sized randomized controlled trials (RCTs) of surgical evacuation are greatly needed. Our aim was to identify and quantify the most important clinical and CT factors related to prognosis in patients with SICH, to estimate the treatment effect in various subpopulations of surgically treated patients and to make assumptions on target population and sample size in future trials. METHODS: Uni- and multivariate analysis of retrospectively collected data on clinical and CT factors on admission and early management in 203 patients with SICH, mortality at discharge, 30 days, 6 and 12 months and clinical outcome according to the modified Rankin Scale (mRS) at 6 months and follow-up at a mean of 3.1 years after admission. RESULTS: Level of consciousness according to the Glasgow Coma Scale (GCS) and age were the single two factors best related to mortality at 6 and 12 months. GCS and age, in association with hematoma volume and location, arterial hypertension and to some extent use of steroids, were also related to clinical outcome according to the mRS at 6 months and 3.1 years. Surgical evacuation seemed to have a positive effect on clinical outcome in only a small subgroup of the patients. CONCLUSIONS: Our data support a future RCT of surgical evacuation versus conservative treatment in SICH restricted to patients younger than 60-65 years with a GCS on admission in the range of 6-11 and a hematoma not mainly located in the thalamus with a volume in the range of 30-100 ml causing a midline shift of less than 10 mm. Randomization should be balanced within groups of patients with lobar and basal ganglion hematomas, arterial hypertension and intraventricular hemorrhage, and the use of steroids should be discouraged.
The development of a radioimmunoassay for S-100 protein is described. This method was used in combination with a recently developed radioimmunoassay for neuron-specific enolase in cerebrospinal fluid and serum from 47 patients with cerebral infarction, transient ischemic attack, intracerebral hemorrhage, subarachnoid hemorrhage, and head injury. In cerebrospinal fluid, increased concentrations of both S-100 and neuron-specific enolase were found after large infarcts, whereas after small infarcts and transient ischemic attacks, only neuron-specific enolase increased. The increased concentrations of S-100 and/or neuron-specific enolase were noted 18 hours to 4 days after cerebral infarction and transient ischemic attacks. Cerebrospinal fluid concentrations of these proteins also reflected the severity of the disease in patients with intracerebral hematoma, subarachnoid hemorrhage, or head injury. Temporal changes in serum S-100 and neuron-specific enolase concentrations reflected the clinical course in 4 patients. In stroke patients, the S-100 and neuron-specific enolase concentrations may reflect the extent of brain damage and could be useful in selecting patients with major stroke for more aggressive treatment during the acute phase.
Recoding of speech in order to improve discrimination for profoundly deaf people has been tried in various ways. One of these is frequency transposition of voiceless consonants. Some authors report positive and very promising results. Others, however, have not found any significant difference when using control groups with normal amplification. One reason might be a poor frequency discrimination. Is it possible to establish what minimum hearing capacity the listener must show for a successful use of frequency transposition? Using noise bands with different Q factors and varying the levels, the thresholds as minimum midfrequency shift have been measured. Great individual variations have been shown. There is a significant difference between (1) threshold values at different Q factors, (2) threshold values at different frequencies, and (3) threshold values for increasing and decreasing frequency, position of deltaf. There is a significant interaction between (1) frequency and position of deltaf, (2) Q factor and position of deltaf, and (3) between Q factor and frequency. There is also a significant triple interaction between Q factor, frequency, and position of deltaf.
The authors studied the effects of mannitol on intracranial pressure (ICP) in experimental focal ischemia in a rat. Stroke was produced by occlusion of middle cerebral artery (MCA). The study revealed that mannitol decreases ICP in ischemic stroke much less then in healthy animals and also a significant rebound effect was seen, especially in the 5th and 7th day after MCA occlusion. The authors suggest a very limited use of mannitol in clinical treatment of elevated ICP after cerebral ischemic stroke.
Changes of neuron-specific enolase (NSE) in cerebrospinal fluid after experimental ischaemic stroke caused by middle cerebral artery occlusion in rat were studied. High enzyme levels were found between the second and seventh day after artery occlusion and they correlated well with the extension of infarct seen in histology. NSE levels in cerebrospinal fluid are sensitive and reliable markers of brain tissue damage during the acute phase of ischaemic stroke.
The value of S-100 protein as a biochemical marker of the extension of brain damage was studied in a rat model of ischaemic stroke. Increased S-100 levels in cerebrospinal fluid were found between the second and fifth day stroke, and the highest values were noted in animals with largest infarcts. In the acute phase ischaemic stroke S-100 protein in cerebrospinal fluid can be useful as a marker of ischaemic brain damage, but further studies on markers of ischaemic stroke are necessary for better diagnosis of cerebral tissue injury.
The effect of the intravenous, continuous nimodipine infusion on ICP in a rat was studied. 5 to 8 minutes after the beginning of infusion ICP started to increase, and at 30 minutes was 35-70% higher than initially, subsequently stabilizing at this level. After finishing the infusion, ICP returned to normal values within 30-45 minutes. The authors discuss possible clinical implications of ICP increase produced by nimodipine.
A particular phenol-formaldehyde resin of the resol type (P-F-R-2) was shown to be a good marker for patients with contact allergy. Eleven patients with sensitivity to P-F-R-2 participated in the study in which chromatographically separated fractions of P-F-R-2 were patch tested. This procedure was repeated until a positive reaction to a single substance was noted. In this study 2 sensitizers are reported. Investigations by mass-spectrometry and nuclear magnetic resonance spectrometry identified the compounds to be 2,4'-dihydroxy-3,3'-di-(hydroxymethyl)-diphenyl methane (2,4'-H-3,3'-HPM) and 2,4'-dihydroxy-3',5'-di-(hydroxymethyl)-diphenyl methane (2,4'-H-3',5'-HPM). Six of 11 patients reacted to at least one of the compounds and simultaneous reactions were noted in 4 patients. By patch testing with serial dilutions of the two sensitizers positive reactions were noted down to 0.14 X 10(-3)% and 0.41 X 10(-3)% w/v for 2,4'-H3,3'-HPM and 2,4'-H-3',5'-HPM respectively.
Patients with cervical root compression were used as a "model" to investigate the possible importance of neck disorders and cervical sensory information in postural control. We assessed postural performance with posturography before and after treatment in 71 consecutive patients with MRI-verified cervical root compression without medullary compression. The patients were randomized to surgery (n = 22), physiotherapy (n = 24) or treatment with cervical collars (n = 25). There were no differences in postural performance or pain intensity between the groups before treatment. After treatment, the surgery group manifested significant improved postural performance and reduced neck pain scores, as compared to the two conservative treatment groups, and their postural performance had improved to the same level manifested by healthy controls. The conservative treatment groups manifested no consistent significant changes in postural performance or pain scores. Decreased muscular tension due to reduction of cervical pain after surgery and normalization of cervical proprioception are suggested as possible explanations of the improved postural control.