PubMed Health⌕ Search

Biomedical subjects

L Frisén

Publications and source records attributed to L Frisén.

At least 19 recordsLinked to original sources
PubMed2006

Polymorphisms of estrogen receptor beta gene are associated with hypospadias.

INTRODUCTION: Hypospadias is a common male congenital urethral malformation, defined as the displacement of the urethral meatus ventrally from the tip of the glans penis. The importance of androgen receptor in male external genitalia development has been well recognized. Recently, the presence of active estrogen receptors (ER) in the developing male external genitalia has also been demonstrated. There are two isoforms of the human estrogen receptor, ESR1 and ESR2, which occur, with distinct tissue and cell patterns of expression. We hypothesized that modifications in these nuclear receptors' genes could lead to hypospadias. MATERIALS AND METHODS: We screened 60 boys with hypospadias for mutations in the coding regions of ESR1 and ESR2 genes, by denaturing high-performance liquid chromatography and automated sequence analysis. We also genotyped the CA repeat polymorphism in ESR2 and the TA repeat polymorphism in ESR1. RESULTS: The CA repeat polymorphism in ESR2 is prolonged in hypospadias patients compared to controls (p < 0.05). Prolongation of this CA repeat polymorphism has previously been associated with lower levels of testosterone. Six patients presented the genetic variant 2681-4A > G (rs944050) in the heterozygous form in ESR2, which was a significantly higher frequency than in the control population (p < 0.05). One of these patients also presented a 266_267insC in exon 1 of ESR2, which is also a known single nucleotide polymorphism (SNP; rs3832949). In ESR1, no significant gene alteration was found to be associated with hypospadias. CONCLUSIONS: Our results suggest that variations in the ESR2 might influence susceptibility to hypospadias.

Chromatography, High Pressure Liquid↗
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↗
PubMed2003

Internal carotid artery aneurysms, cranial nerve dysfunction and headache: the role of deformation and pulsation.

Cranial nerve dysfunction and headache may occur with unruptured aneurysms of the cavernous and supraclinoid portions of the internal carotid artery. Nerve deformation (mass effect) and transmitted pulsations have been suggested as pathogenetic mechanisms. Differentiation may be possible by studying effects of endovascular treatment with Guglielmi detachable coils. Symptoms and signs of cranial neuropathy were retrospectively contrasted with angiographic aneurysm volumes before and after treatment in 10 patients. Mean follow-up was 36 months. Symptoms improved in three of four patients with cranial nerve dysfunction and in all patients with headache. None of the other patients, one with cranial nerve dysfunction, and three who were asymptomatic, developed any new symptoms after treatment. Aneurysm volume ranged from 0.1 to 2.7 cm(3 )before and 0.2 to 5.7 cm(3) after treatment; the size thus increased by 15 to 110%, a change which was statistically significant (P=0.004). The consistent increase in aneurysm volume with treatment is not associated with clinical deterioration, suggesting that deformation and displacement play a minor role in cranial neuropathy and that transmitted pulsations may be more important.

Adult↗
PubMed2003

Multiple sclerosis siblings with cerebrospinal fluid immunopathy but without any indication of neuronal damage.

OBJECTIVE: In a previous study, we found that nine of the 47 siblings to multiple sclerosis (MS) patients with a normal neurologic examination carry an intrathecal oligoclonal immunopathy with limited specificity, a condition we termed MS immunopathic trait. Here we searched for neurological dysfunction with increased sensitivity. METHOD: We used high-pass resolution perimetry, which reveals visual pathway lesions by their impaired neural effective capacity (EC) in early MS cases even without optic neuritis. RESULTS: These nine individuals with MS immunopathic trait did not differ from nine healthy controls with normal cerebrospinal fluid regarding their EC. CONCLUSION: This is further evidence that a group of MS immunopathic trait individuals, siblings to MS patients, are essentially free from the central nervous system functional loss typically found in MS.

Female↗
PubMed2003

Spatial vision in visually asymptomatic subjects at high risk for multiple sclerosis.

OBJECTIVE: To investigate the state of spatial vision in visually asymptomatic subjects at high risk for multiple sclerosis. METHODS: Fifteen subjects suffering a first neurological episode suggestive of multiple sclerosis in clinical presentation, immunological profile, and magnetic resonance imaging, were examined with a new, sensitive test of spatial vision, rarebit perimetry. None had symptoms or signs of optic neuropathy. RESULTS: Results of rarebit perimetry were significantly worse than those of 15 age matched normal controls (p=0.01); seven patients (47%) were outside normal limits. One patient only obtained abnormal results in high pass resolution perimetry. CONCLUSIONS: Rarebit perimetry may help to close the sensitivity gap between clinical examinations and neuroimaging.

Acute Disease↗
PubMed2001

Asymptomatic visual loss in multiple sclerosis.

Visual disturbances are common in multiple sclerosis (MS) and often a result of acute demyelinating optic neuropathy. Careful examination of MS patients, who have never suffered optic neuritis, may also reveal asymptomatic visual loss. This type of silent disease activity was investigated by computerised resolution perimetry, which has the potential to reflect the percentage of functional retino-cortical neural channels. The time of onset and the evolution of asymptomatic visual loss was investigated. One approach was to retrospectively select patients who never had suffered acute optic neuritis from a closely monitored MS population and re-examine them again. Sixteen patients were identified and vision was evaluated during a period of 5.5-9 years of follow-up and compared with that in 14 healthy controls. The mean channel percentage of the MS group was 89 +/- 19 % (SD) on entry into the study, compared with 110 +/- 15% (SD) of controls (p < 0.003). At termination of the study the mean percentage was essentially unchanged both in MS patients (87 +/- 21%, SD) and controls (110 +/- 19%, SD). The second approach was to test a group of 7 patients with MS or strongly suspected MS, with the same method, in close connection with their first clinical exacerbation. All cases lacked visual symptoms and none had previously had acute visual loss. Again, virtually all performed subnormally in the vision tests, and to the same degree as in the first group of patients. Results were compared with those obtained from 25 MS patients who had experienced one or more attacks of optic neuritis. Compared with controls the loss of functional retino-cortical neural channels was 20% in patients without a previous history of optic neuritis and 30 % in patients who previously had experienced optic neuritis. We conclude that asymptomatic visual loss seems to be a universal feature of MS and has a substantial impact on the visual pathways, that it is present already at the time of clinical onset of the disease, and that any progression thereafter is slow enough to elude detection during several years of follow-up.

Adult↗
PubMed2001

Vigabatrin visual toxicity: evolution and dose dependence.

PURPOSE: To investigate the prevalence and prognosis of visual field defects (VFDs) in epilepsy patients with and without vigabatrin (VGB) treatment; to investigate the possible relationship between VFDs and cumulative VGB dose, and to characterise the evolution of VFDs. METHODS: A cohort of 155 presurgical candidates who had undergone full-field Goldmann perimetry (GP) was studied, 99 (64%) of whom had been treated with VGB. All GPs were reevaluated in 1998 by one experienced examiner, blinded to medication. Duration of treatment and total VGB dose were related to perimetric results. RESULTS: Twenty-five (16%) of the 155 patients had VFDs: Nineteen (19%) of the 99 VGB-treated patients, and six (11%) of the 56 patients unexposed to VGB. VGB-treated patients with VFDs had been treated significantly longer than those without VFDs. Cumulative VGB dose could be calculated for 84 patients. The prevalence of VFDs increased significantly with increasing total VGB-dose, from 4% in the 51 patients who had been exposed to <or=1 kg VGB, to 75% in the eight patients with a total dose of 3-5 kg of VGB. Sixteen VGB-treated patients were reexamined 2-10 years later. In the 12 where evaluation was possible, all still had VFDs, which had worsened in five cases (42%) and improved in none. CONCLUSIONS: This study indicates a strong relationship between VFDs and duration and total dose of VGB. VFDs were irreversible and in a substantial percentage progressive. Similar VFDs may, however, also be found in patients unexposed to VGB. A model of the evolution of the VFDs in VGB toxicity is introduced, and a new simple visual field test is proposed.

Adult↗
PubMed2000

Gabapentin versus vigabatrin as first add-on for patients with partial seizures that failed to respond to monotherapy: a randomized, double-blind, dose titration study. GREAT Study Investigators Group. Gabapentin in Refractory Epilepsy Add-on Treatment.

PURPOSE: Our objective was to compare the efficacy and safety of gabapentin and vigabatrin as first-line add-on treatment in patients with partial epilepsy. METHODS: This was a multicenter, double-blind, randomized dose titration study. After baseline assessment and randomization, the dose could be increased if seizures persisted and reduced if side effects occurred. Health-related quality of life was assessed at baseline and at the end of the study. By a protocol amendment post hoc, all randomized patients were offered a standardized perimetry examination at the end of the study. Improvement rate was the proportion of patients with a reduction of seizure frequency of at least 50% during an 8-week period without any adverse events causing withdrawal. RESULTS: One hundred two patients were randomized and analyzed on an intent-to-treat basis. The improvement rate was 48% in the gabapentin group and 56% in the vigabatrin group. The improvement rate, when per protocol criteria were fulfilled, was 57% in the gabapentin group and 59% in the vigabatrin group. The proportion of seizure-free patients was 31% in the gabapentin group and 39% in the vigabatrin group. There was no difference in quality-of-life scores between the groups. Perimetry after termination of the study on 64 patients showed abnormal results in 3 of 32 patients in the vigabatrin group. CONCLUSION: Approximately one third of the patients in both groups became seizure-free. Although no major differences were seen in terms of the improvement rate between the groups, equivalence between the two drugs was not found.

Acetates↗
PubMed1999

Surgically created fourth-third cranial nerve communication: temporary success in a child with bilateral third nerve hamartomas. Case report.

Shortly after birth, an otherwise healthy infant developed eye deviation and ptosis due to a hamartomatous lesion of the interpeduncular segment of the right oculomotor nerve. The left nerve became similarly involved when the child was 1.5 years of age. Direct nerve repair was not possible. Instead, the trochlear nerve was divided and its proximal end was attached to the distal end of the third nerve. Elevation of the upper eyelid and partial adduction of the eye developed gradually over the ensuing 3 to 5 months. Both functions were lost after an additional 2 months, presumably as a result of tumor recurrence or neuroma formation. This case report shows that surgically created fourth-third cranial nerve communication is feasible and may merit consideration under similar circumstances.

Anastomosis, Surgical↗
PubMed1996

Acyclovir treatment of relapsing-remitting multiple sclerosis. A randomized, placebo-controlled, double-blind study.

Acyclovir treatment was used in a randomized, double-blind, placebo-controlled clinical trial with parallel groups to test the hypothesis that herpes virus infections are involved in the pathogenesis of multiple sclerosis (MS). Sixty patients with the relapsing-remitting form of MS were randomized to either oral treatment with 800 mg acyclovir or placebo tablets three times daily for 2 years. The clinical effect was investigated by an extensive test battery consisting of neurological examinations, neuro-ophthalmological and neuropsychological tests, and evoked potentials. Results were based on "intent-to-treat" data and the primary outcome measure was the exacerbation rate. In the acyclovir group (n = 30), 62 exacerbations were recorded during the treatment period, yielding an annual exacerbation rate of 1.03. The placebo group (n = 30) had 94 exacerbations and an annual exacerbation rate of 1.57. Thus, 34% fewer exacerbations were encountered during acyclovir treatment. This difference in exacerbation rate between the treatment groups was not significant (P = 0.083). However, this trend to a lower disease activity in acyclovir-treated patients was supported in subsequent data analysis. If the patients were grouped according to exacerbation frequencies, i.e. into low (0-2), medium (3-5) and high (6-8) rate groups, the difference between acyclovir and placebo treatment was significant (P = 0.017). Moreover, in a subgroup of the population with a duration of the disease of at least 2 years providing an exacerbation rate base-line before entry, individual differences in exacerbation rates were compared between the 2-year pre-study period and the study period in acyclovir-treated (n = 19) and placebo (n = 20) patients and acyclovir-treated patients showed a significant reduction of exacerbations (P = 0.024). Otherwise, neurological parameters were essentially unaffected by acyclovir treatment and there were no convincing signs of reduced neurological deterioration in the acyclovir group. This study indicates that acyclovir treatment might inhibit the triggering of MS exacerbations and thus suggests that acyclovir-susceptible viruses might be involved in the pathogenesis of MS. This possibility warrants further investigation.

Acyclovir↗
PubMed1996

Relative dispersion analysis enhances perimetric sensitivity.

Objective identification of minor visual field defects is problematic. A possible solution is to examine spatial correlations by means of relative dispersion analysis, a tool of fractal analysis. We studied patients with glaucoma, previous optic neuritis, chiasmal compression and lesions of the brain hemispheres, using high-pass resolution perimetry. One-hundred visual field records were drawn consecutively for each category and ranked according to severity of defects. Records with scores ranking below the 35th percentile, i.e. those with the smallest field defects, were analysed. Relative dispersion analysis recognized 1.3-2.4 times more abnormal subjects than did pattern standard deviation. A previously described form index was intermediate in sensitivity. Specificity was 96%. Relative dispersion analysis appears to capture a novel aspect of visual field abnormality, with good sensitivity and specificity. The analysis is easily performed.

Adolescent↗
PubMed1995

High-pass resolution perimetry: central-field neuroretinal correlates.

Minimum angles of resolution (MAR) were measured at 0-10 deg horizontal eccentricity in three normal subjects, using high-pass spatial frequency filtered targets, at four different contrast levels. Results were correlated with recent data on human cone and ganglion cell separations in corresponding retinal locations. MARs and cone separations showed a close proportionality through the origin for all contrast levels. Ganglion cell correlates were more difficult to elucidate as the cell bodies are displaced from their input cones. Taking a functional estimate of the displacement into account, the number of ganglion cells appeared to be large enough to uphold an "effective" distribution that obeys the same proportional relationship to MAR that previously has been demonstrated outside 10 deg. Analysis of the nature of age effects provided support for this model.

Adult↗
PubMed1994

Remodelling of the retinal arterioles in descending optic atrophy follows the principle of minimum work.

Mathematical modelling indicates that the minimum energy cost for blood flow is achieved when the arteries are arranged in a branching hierarchy such that the radii of the vessels are adjusted to the cube root of the volumetric flow (principle of minimum work). This is known to apply over several magnitudes of vessel calibres, and in many different organs, including the brain, in humans and in animals. This paper addresses the issue of remodelling of one and the same arterial network to long-term changes in blood flow. This has not been studied previously in humans. We measured the radius of parent (r0) and branch segments (r1 and r2) of the retinal arteriolar network in fundus photographs of six patients with blinding, non-vascular retrobulbar optic nerve lesions, mostly traumatic in origin, before and after the development of descending optic atrophy. Attenuation of retinal arterioles is a well-known phenomenon in descending optic atrophy, and is attributable to decreased metabolic demand secondary to loss of the retinal ganglion cells and their axons. On average, arteriolar diameters decreased by 15.2 +/- 17.7% (SD), with 95% confidence intervals of 18.7% and 11.7%; the radii decreased significantly (P = 0.0001) (n = 99). The area ratio of the bifurcations, defined as (r2(1) + r2(2))r-2(0), was 1.23 +/- 0.2 before, and 1.18 +/- 0.2 after optic atrophy (n = 36); the change of area ratio was not significant. The branching geometry of the retinal arteriolar network obeyed strictly the optimum branching rule of the principle of minimum work, or r3(0) = r3(1) + r3(2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

High-pass resolution perimetry. A clinical review.

Review of all available reports comparing high-pass resolution perimetry (HRP) and conventional perimetry in normals and in subjects with different visual disorders reveals closely comparable aspects of sensitivity, specificity, and reliability. HRP shows important advantages concerning variability, test duration, and subject preferences. Drawbacks seem largely limited to somewhat loose renditions of visual field defects of small area and large depth. Otherwise HRP's novel format of graphic result presentation may be better suited to visual evaluation than conventional gray-scale maps with their lumping of thresholds and extensive interpolations. Several examples are provided of visual field defects due to various lesions throughout the visual system.

Glaucoma↗
PubMed1993

Properties of high-pass resolution perimetry targets.

Relationships between high-pass resolution perimetry ring targets and conventional perimetry and acuity targets were explored by optical analytical techniques and by comparative measurements in normal humans. High-pass resolution and acuity targets produced closely proportional resolution measurements, showing that the critical ring detail is the width of the bright core. High-pass resolution and conventional perimetry thresholds were not equally well correlated. From a purely optical point of view, high-pass resolution targets appeared to lose somewhat more contrast on defocusing. On the other hand, high-pass resolution appears to show less variability in practical, clinical use.

Adult↗