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Biomedical subjects

A Dahl

Publications and source records attributed to A Dahl.

At least 19 recordsLinked to original sources
PubMed1998

Progressive pseudobulbar paresis, early choreiform movements, and later rigidity: appearance in two sets of dizygotic twins in the same family.

In a family with two sets of dizygotic twins, three, possibly all four, siblings were affected by the same disorder. The parents were unrelated and the illness seemed limited to one generation. Onset was in the early to mid-20s with tics and choreiform movements, dysarthria, and dysphagia. Two twins had epilepsy. There was a marked dyscoordination of bulbar musculature reminiscent of pseudobulbar paresis. Involuntary movements were prominent during the first years, but then disappeared and were replaced by an akinetic-rigid parkinsonian appearance in the late stage. The intellect remained largely intact. Tendon reflexes were reduced. Varying degrees of peripheral nerve changes were seen. Two patients died after 22-24 years from causes indirectly related to the main illness. Marked degenerative changes were found in the caudate nucleus and putamen. Acanthocytes in significant numbers could not be detected in peripheral blood. Lipoproteinelectrophoresis was normal. Creatine kinase levels were moderately raised in one patient, normal in the others. Although certain clinical resemblances exist with neuroacanthocytosis, the exact nosologic status of the disorder has not been determined.

Adult↗
PubMed1997

Intrinsic balancing in reconstruction of the tetraplegic hand.

This article reviews 183 hand reconstructions in 135 consecutive tetraplegic patients. Comparisons were made between 103 extrinsic reconstructions with intrinsic balancing procedures and 80 extrinsic reconstructions without intrinsic balancing procedures. Extrinsic reconstructions (tendon transfers and tenodesis in the forearm muscles) were augmented by intrinsic reconstructive procedures (tendon transfers or tenodesis to improve the intrinsic balance of the fingers) in patients exhibiting digital imbalance. Intrinsic procedures included primarily the flexor digitorum superficialis (FDS) lasso procedure or the intrinsic tenodesis procedure. The patients were stratified by level of spinal cord injury and by type of extrinsic and intrinsic reconstruction. Hands reconstructed with intrinsic balancing versus without intrinsic balancing, as well as intrinsic balancing using a FDS lasso procedure versus an intrinsic tenodesis procedure, were compared with patients with the same level of spinal cord function. Patients who underwent reconstructions with intrinsic balancing had more grip strength, by an average of 13-26 N, than those who did not undergo intrinsic balancing. When different intrinsic procedures were compared, there was improvement in grip strength and function in activities of daily living for all hands, but there was no significant difference between FDS lasso or intrinsic tenodesis procedures. The indications for intrinsic balancing during extrinsic reconstruction are developed into treatment algorithms based on the senior author's surgical experience. The authors recommended that digital intrinsic procedures be included in hand reconstruction for tetraplegic patients exhibiting intrinsic imbalance to help improve digital function and provide increased grip strength.

Adolescent↗
PubMed1996

Assessment of the ophthalmic artery as a collateral to the cerebral circulation. A comparison of transorbital Doppler ultrasonography and regional cerebral blood flow measurements.

The role of the ophthalmic artery (OA) as a collateral to the cerebral circulation in carotid occlusive disease is somewhat controversial. The aim of this study was to assess the importance of this collateral by comparing the results of transorbital Doppler ultrasonography and regional cerebral blood flow measurements using SPECT and Xenon-133 inhalation in 41 patients with unilateral high-grade internal carotid artery occlusive disease. Both measurements were performed under basal conditions and after the intravenous administration of 1 g acetazolamide to test cerebral vasoreactivity. Based on the direction of OA flow, the patients could be divided into three groups. In Group 1 (n = 16) with anterograde OA flow before and after acetazolamide, baseline rCBF values did not differ significantly between the two sides, or from those of the controls. The side-to-side asymmetry of the response to acetazolamide was also normal. In Group 2 (n = 11) where the OA flow was anterograde or "0 flow" before, but became retrograde after acetazolamide, rCBF was significantly reduced on the symptomatic compared to the non-symptomatic side under basal conditions. However, the increase in rCBF after acetazolamide was within normal limits. In Group 3 (n = 14) the OA flow was reversed both under basal conditions and after the vasodilatory stimulus. Baseline rCBF was significantly lower (p < 0.05) on the symptomatic side compared to the non-symptomatic, and the asymmetry became even greater (p < 0.001) after acetazolamide. Our findings demonstrate that the OA may be an important collateral pathway in patients with ICA occlusive disease, and contribute to the cerebral perfusion reserve in the case of compromised blood supply.

Acetazolamide↗
PubMed1996

Cervicocranial artery dissection. Detection by Doppler ultrasound and MR angiography.

PURPOSE: To evaluate pulsed Doppler ultrasound and MR angiography (MRA) in the diagnosis of cervicocranial dissection. MATERIAL AND METHODS: Fourteen patients with cervicocranial artery dissection were examined over a 3-year period. Twelve patients had dissection of the extracranial part of the internal carotid artery, and 2 had vertebral artery dissection. All patients were examined with pulsed Doppler ultrasound. In addition, all patients had conventional angiography (n = 9) and/or MR imaging including MRA (n = 9). RESULTS: Doppler ultrasound disclosed unspecific abnormalities in 11 of 14 dissected vessels; 3 patients had false-negative Doppler findings. MRA showed vessel abnormalities in 9 of 9 patients; 2 vessels were occluded, and 7 vessels had changes typical of dissection (double lumen and/or string sign). Twelve patients had follow-up examinations with pulsed Doppler ultrasound (n = 12), conventional angiography (n = 3), and MRA/MR (n = 11). Follow-up Doppler showed complete or partial normalization in 6 of 9 patients, all confirmed by either angiography or MRA. CONCLUSION: Our findings suggest that Doppler ultrasound may be used in follow-up of pathologic Doppler findings in known dissections, and that MRA may replace angiography in the confirmative diagnosis of cervicocranial dissection.

Adult↗
PubMed1995

A new X linked recessive deafness syndrome with blindness, dystonia, fractures, and mental deficiency is linked to Xq22.

X linked recessive deafness accounts for only 1.7% of all childhood deafness. Only a few of the at least 28 different X linked syndromes associated with hearing impairment have been characterised at the molecular level. In 1960, a large Norwegian family was reported with early onset progressive sensorineural deafness, which was indexed in McKusick as DFN-1, McKusick 304700. No associated symptoms were described at that time. This family has been restudied clinically. Extensive neurological, neurophysiological, neuroradiological, and biochemical, as well as molecular techniques, have been applied to characterise the X linked recessive syndrome. The family history and extensive characterisation of 16 affected males in five generations confirmed the X linked recessive inheritance and the postlingual progressive nature of the sensorineural deafness. Some obligate carrier females showed signs of minor neuropathy and mild hearing impairment. Restudy of the original DFN-1 family showed that the deafness is part of a progressive X linked recessive syndrome, which includes visual disability leading to cortical blindness, dystonia, fractures, and mental deficiency. Linkage analysis indicated that the gene was linked to locus DXS101 in Xq22 with a lod score of 5.37 (zero recombination). Based on lod-1 support interval of the multipoint analysis, the gene is located in a region spanning from 5 cM proximal to 3 cM distal to this locus. As the proteolipid protein gene (PLP) is within this region and mutations have been shown to be associated with non-classical PMD (Pelizaeus-Merzbacher disease), such as complex X linked hereditary spastic paraplegia, PLP may represent a candidate gene for this disorder. This family represents a new syndrome (Mohr-Tranebjaerg syndrome, MTS) and provides significant new information about a new X linked recessive sydromic type of deafness which was previously thought to be isolated deafness.

Adolescent↗
PubMed1995

Cerebral vasoreactivity assessed with transcranial Doppler and regional cerebral blood flow measurements. Dose, serum concentration, and time course of the response to acetazolamide.

BACKGROUND AND PURPOSE: To improve the assessment of cerebral vasoreactivity using acetazolamide (ACZ), we studied the time course of the response and the relationship between dose, response, and serum concentration. METHODS: Blood flow velocities were measured with the use of transcranial Doppler ultrasonography in one of the middle cerebral arteries of 48 healthy subjects after the intravenous administration of 1 to 1.6 g ACZ. In 34 subjects (group 1), velocities were measured every second minute to detect the maximum middle cerebral artery velocity increase. We also measured regional cerebral blood flow using single-photon emission computed tomography in 27 of the subjects in group 1 before and approximately 15 to 20 minutes after the ACZ injection. The serum concentration of ACZ was measured in 15 subjects. In the remaining 14 subjects (group 2), middle cerebral artery velocity measurements were made 10, 25, 30, and 45 minutes after ACZ administration to obtain information regarding the late time course of the response. RESULTS: In group 1 the plateau phase of the velocity response was reached 8 to 15 minutes after ACZ administration. A large range of velocity increase was observed, and a significant correlation was found between the maximum velocity increase and the dose and serum concentration of ACZ. In group 2 subjects, maximum velocities were maintained 30 minutes after the injection, but after 45 minutes velocities had decreased to 68% of their highest level. No significant relationship was found between dose or serum concentration of ACZ and the regional cerebral blood flow increase. The velocity increase after ACZ was similar in both older and younger subjects. CONCLUSIONS: This study shows that cerebral vasoreactivity is best assessed 10 to 30 minutes after ACZ administration and that the dose should probably exceed 15 mg/kg if a maximum vasodilatory response in the cerebral circulation is to be obtained.

Acetazolamide↗
PubMed1994

The International Personality Disorder Examination. The World Health Organization/Alcohol, Drug Abuse, and Mental Health Administration international pilot study of personality disorders.

BACKGROUND: One of the aims of the World Health Organization/Alcohol, Drug Abuse, and Mental Health Administration joint program on psychiatric diagnosis and classification is the development and standardization of diagnostic assessment instruments for use in clinical research worldwide. The International Personality Disorder Examination (IPDE) is a semistructured clinical interview compatible with the International Classification of Diseases, Tenth Revision, and the DMS-III-R classification systems. This is the first report of the results of a field trial to investigate the feasibility of using the IPDE to assess personality disorders worldwide. METHODS: The IPDE was administered by 58 psychiatrists and clinical psychologists to 716 patients enrolled in clinical facilities at 14 participating centers in 11 countries in North America, Europe, Africa, and Asia. To determine interrater reliability, 141 of the IPDEs (20%) were independently rated by a silent observer. To determine temporal stability, 243 patients (34%) were reexamined after an average interval of 6 months. RESULTS: The IPDE proved acceptable to clinicians and demonstrated an interrater reliability and temporal stability roughly similar to instruments used to diagnose the psychoses, mood, anxiety, and substance use disorders. CONCLUSION: It is possible to assess personality disorders with reasonably good reliability in different nations, languages, and cultures using a semistructured clinical interview that experienced clinicians find relevant, meaningful, and user-friendly.

Adult↗
PubMed1994

Inhibition of lipases by phosphonates.

Ethyl hexylchlorophosphonate and analogues thereof were investigated as inhibitors of lipases. Both microbial and mammalian lipases were irreversibly inhibited. The inhibition could be monitored by p-nitrophenol release from the corresponding ethyl p-nitrophenyl hexylphosphonate inhibitor. Quantitative analysis of the data indicated that a 1:1 lipase-inhibitor complex was formed during inhibition. Enantioselective inhibition was found for the lipases derived from Candida antarctica and Rhizomucor miehei using pure enantiomers of ethyl p-nitrophenyl hexylphosphonate as inhibitors. Using the same inhibitor, reversed enantioselectivity was found for the protease alpha-chymotrypsin as compared to the two lipases.

Animals↗
PubMed1994

Simultaneous assessment of vasoreactivity using transcranial Doppler ultrasound and cerebral blood flow in healthy subjects.

Blood flow velocities in both middle cerebral arteries and regional cerebral blood flow in their perfusion territories were measured simultaneously in 36 healthy subjects. In 20 subjects, the measurements were first performed under basal conditions and then repeated 15-20 min after an intravenous injection of 1 g of acetazolamide. Reproducibility of simultaneous blood flow and velocity measurements was tested by examining 16 subjects on two occasions under basal conditions with an interval of 20 min. Relatively good reproducibility was found for repeated measurements of velocity and blood flow, being best when side-to-side asymmetry was assessed. The increase in blood flow velocities after acetazolamide was symmetrical (right side, 34.2%; and left side, 35.5%), and the velocity increase was significantly correlated with basal values. The increase in cerebral blood flow was also symmetrical (right side, 29.8%; left side, 30.1%) but not correlated with basal flow values. No significant relationship was found between velocity increase and increase in regional cerebral blood flow. This finding is probably not only due to methodological inaccuracies but may suggest that acetazolamide has an effect on the diameter of the middle cerebral artery or on the magnitude of this artery's perfusion territory. This study supports the use of acetazolamide for assessing cerebral vasoreactivity following the definition of lower limits for velocity and flow increase and for asymmetry of the response.

Acetazolamide↗
PubMed1994

Ocular and cerebral blood flow measurements in healthy subjects. A comparison of blood flow velocity and dynamic tonometry measurements before and after acetazolamide.

The ocular and cerebral blood flow was studied in 15 healthy subjects using transcranial Doppler ultrasonography (2 MHz). The blood flow velocity in the precerebral carotid arteries, in the ophthalmic artery and in the middle cerebral artery was measured under baseline conditions and after i.v. administration of 1 g acetazolamide. To measure the intraocular pressure and the corneal indentation pulse amplitude, a dynamic tonometer was used. Pulsatile ocular blood volume was calculated from these values. After one single dose of acetazolamide a significant decrease in ophthalmic artery flow velocity, and a significant increase both in internal carotid and in middle cerebral artery velocity was found. A significant decrease in intraocular pressure and in pulsatile ocular volume after acetazolamide was also demonstrated. These findings suggest that the acute effect of acetazolamide may be associated with a reduced ocular blood flow, explaining some of the reduction in IOP.

Acetazolamide↗
PubMed1994

Cerebral vasoreactivity in unilateral carotid artery disease. A comparison of blood flow velocity and regional cerebral blood flow measurements.

BACKGROUND AND PURPOSE: Hemodynamic information obtained by assessing cerebral vasoreactivity is of clinical interest and may have prognostic significance in patients with occlusive carotid disease. The aim of this study was to compare the results of transcranial Doppler and regional cerebral blood flow studies when used to assess cerebral vasoreactivity. METHODS: Blood flow velocities in both middle cerebral arteries and regional cerebral blood flow in their respective perfusion territories were compared in 52 patients with severe unilateral carotid stenosis or occlusion. The studies were first performed under basal conditions and repeated after the intravenous administration of 1 g acetazolamide. RESULTS: Asymmetry (normal compared with pathological side) in middle cerebral artery blood velocity increase was significantly greater than the asymmetry in cerebral blood flow increase in the perfusion territories of the arteries. A significant correlation (r = .63, P < .0001) was found between asymmetry in percent velocity increase and asymmetry in absolute cerebral blood flow increase. The two methods agreed in their assessment of either a normal or a reduced vasoreactivity in 38 subjects and disagreed in 14. In six of the latter patients, who had no evidence of cerebral infarction, the asymmetry in velocity increase was abnormal, whereas asymmetry in flow increase was assessed as normal. CONCLUSIONS: We found a good correlation between the asymmetry in regional cerebral blood flow increase in the middle cerebral artery perfusion territories and asymmetry in the velocity increase in the middle cerebral arteries after administration of acetazolamide. These results suggest that transcranial Doppler examination combined with the acetazolamide test may be used in clinical situations to assess cerebral vasoreactivity.

Adult↗
PubMed1992

A comparison of regional cerebral blood flow and middle cerebral artery blood flow velocities: simultaneous measurements in healthy subjects.

Blood flow velocities were measured in both middle cerebral arteries (MCAs) of 36 healthy subjects using transcranial Doppler ultrasound. Measurements were first made using a hand-held probe. Velocities were then studied bilaterally with fixed probes under resting conditions and during simultaneous regional CBF (rCBF) measurements. A significant (p < 0.05) positive correlation was found between MCA flow velocities and rCBF in the estimated perfusion territory of this artery. The correlation coefficient was highest when the measurements were performed simultaneously (p < 0.001) or when velocities recorded with a hand-held probe were adjusted to take into account the significant velocity increase induced by the CBF study situation. The increased velocities during CBF measurements cannot be fully explained by the moderate but significant PCO2 increase. Other possible mechanisms are increased blood flow due to mental activation or MCA vasoconstriction secondary to stimulation of the sympathetic nervous system. The effect of mental activation and PCO2 differences should therefore be considered when comparing the results of repeated velocity and CBF measurements.

Adult↗
PubMed1992

Effect of pre- vs postoperative inguinal field block on postoperative pain after herniorrhaphy.

The analgesic effects of an identical inguinal field block, performed before or immediately after inguinal herniorrhaphy, were evaluated in 32 healthy patients in a double-blind, randomized study. During surgery, all patients received a light general anaesthesia with thiopentone, alfentanil and nitrous oxide in oxygen. After induction of general anaesthesia, patients were allocated randomly to receive an inguinal field block with lignocaine, either 15 min before operation or immediately after operation, after closure of the surgical wound, but before the patients were awake. Pain score on a visual analogue scale and on a verbal scale at rest, during mobilization from supine into sitting position and during cough was assessed 1, 2, 4, 6, 8 and 24 h, and 7 days after operation. No significant differences between the groups were observed in VAS scores or verbal pain scores during rest or ambulation at any time. There was no significant difference in time to first request for morphine or total morphine consumption. These results do not show pre-emptive analgesia with a conventional inguinal field block to be of clinical importance compared with a similar block administered after operation.

Adult↗
PubMed1992

Cerebral blood flow findings in moyamoya disease in adults.

Three adult patients with moyamoya disease are described. They presented with intracerebral hematoma, cerebral infarction and subarachnoid hemorrhage, respectively. Subarachnoid hemorrhage is rare in moyamoya and is usually the result of aneurysm rupture. No aneurysm was found in our patient. Regional cerebral blood flow (rCBF) and the cerebral perfusion reserve assessed by the acetazolamide test, were significantly reduced in all three patients. The areas with most reduced baseline rCBF and most impaired vasoreactivity did not always correspond to the site of the vascular accident, indicating that these CBF changes were at least in part due to the moyamoya disease and/or its underlying causes, and not solely to the vascular accidents.

Adult↗
PubMed1992

A comparison of transcranial Doppler and cerebral blood flow studies to assess cerebral vasoreactivity.

BACKGROUND AND PURPOSE: The aim of this study was to determine the ability of transcranial Doppler ultrasonography when used to assess cerebral vasoreactivity. The results of this method were compared with regional cerebral blood flow measurements. METHODS: Forty-three patients with symptoms suggesting cerebrovascular disease took part. Transcranial Doppler findings in the middle cerebral arteries were compared with regional cerebral blood flow in the corresponding perfusion territories before and after acetazolamide administration. RESULTS: There was a significant positive correlation between the absolute increase in cerebral blood flow in milliliters per 100 g per minute and the percent increase in velocity (r = 0.63). The right-left, side-to-side difference of the acetazolamide response obtained by the two methods also showed a positive correlation (r = 0.80). Control limits obtained from healthy subjects were used for both the blood flow increase (absolute values and asymmetry in absolute values) and the velocity increase (percent increase and asymmetry in percent increase). The two methods then agreed in their evaluation of vasoreactivity in 74 (86%) of the 86 middle cerebral artery perfusion territories; 20 (23%) were assessed by both methods as having a reduced vasodilatory reserve. Eleven hemispheres with a slightly reduced regional cerebral blood flow response to acetazolamide were not detected by transcranial Doppler, whereas all territories with a marked reduction were identified by Doppler. Only one hemisphere with a normal cerebral blood flow increase after acetazolamide administration was assessed by Doppler as having reduced vasoreactivity. CONCLUSIONS: Transcranial Doppler and the acetazolamide test may be used in clinical situations to assess cerebral vasoreactivity.

Acetazolamide↗
PubMed1990

Cluster headache: transcranial Doppler ultrasound and rCBF studies.

Transcranial Doppler and rCBF examinations were carried out in 25 cluster headache patients. Spontaneous and glyceryl trinitrate (nitroglycerin) provoked attacks were accompanied by a bilateral decrease in middle cerebral artery blood flow velocities. This decrease was more pronounced on the symptomatic side but the difference did not reach statistical significance. Mean hemispheric blood flow and rCBF were within normal limits during provoked attacks and similar to those found when patients were attack-free. During cluster periods middle cerebral artery velocities were significantly higher on the symptomatic side. Glyceryl trinitrate caused a bilateral middle cerebral artery velocity decrease which was significantly greater on the symptomatic side. Attacks provoked by glyceryl trinitrate appeared to begin when the vasodilatory effect of this substance was receding.

Adult↗