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Biomedical subjects

S Beer

Publications and source records attributed to S Beer.

At least 37 records · Page 2Linked to original sources
PubMed2000

The impact of different response alternatives on responders' reporting of health-related behaviour in a postal survey.

Previous experimental research in other topic areas has shown that the choice of response alternatives can influence respondents' reporting of the frequency of vaguely defined events and that the set of response alternatives is treated as information in the interpretation of the question. The aim of this study was to examine whether such affects would occur in the context of respondents reporting of health-related events using high and medium frequency closed format response categories, which might be used interchangeably by researchers. The study consisted of a postal survey of n = 518 patients aged > or = 18 years randomly selected from the patient list of a diabetes centre and who were equally and randomly allocated to one of three conditions (Condition A: high frequency response alternatives/horizontal orientation; condition B: medium frequency response alternatives/horizontal orientations; condition C: high frequency response alternatives/vertical orientation). Testing for the effect of response alternatives for the combined responses of five vaguely defined questions between conditions A and B was chi 2 = 5.5, p = 0.019, for the difference in proportions, indicating that overall, those respondents presented with response alternatives discriminating at medium frequency, reported significantly fewer target events than those presented with high frequency response alternatives. Testing for the effect of orientation of the combined question responses between conditions A and C, differences in proportions between conditions, did not reach statistical significance (p > 0.05). Findings from this and previous studies indicate that response alternatives provide information on the interpretation of vaguely defined questionnaire items and that their choice should not be left to intuition alone when designing questionnaire items.

Adult↗
PubMed1999

Integrin and neurocan binding to L1 involves distinct Ig domains.

The cell adhesion molecule L1, a 200-220-kDa type I membrane glycoprotein of the Ig superfamily, mediates many neuronal processes. Originally studied in the nervous system, L1 is expressed by hematopoietic and many epithelial cells, suggesting a more expanded role. L1 supports homophilic L1-L1 and integrin-mediated cell binding and can also bind with high affinity to the neural proteoglycan neurocan; however, the binding site is unknown. We have dissected the L1 molecule and investigated the cell binding ability of Ig domains 1 and 6. We report that RGD sites in domain 6 support alpha5beta1- or alphavbeta3-mediated integrin binding and that both RGD sites are essential. Cooperation of RGD sites with neighboring domains are necessary for alpha(5)beta(1). A T cell hybridoma and activated T cells could bind to L1 in the absence of RGDs. This binding was supported by Ig domain 1 and mediated by cell surface-exposed neurocan. Lymphoid and brain-derived neurocan were structurally similar. We also present evidence that a fusion protein of the Ig 1-like domain of L1 can bind to recombinant neurocan. Our results support the notion that L1 provides distinct cell binding sites that may serve in cell-cell or cell-matrix interactions.

Animals↗
PubMed1999

Detection of anterior horn lesions by MRI in central European tick-borne encephalomyelitis.

We report a case of central European tick-borne encephalitis with cervical myelitis presenting clinically as a lower motor neuron syndrome of the upper limbs with proximal asymmetrical pareses and atrophies. There were no sensory deficits nor signs of lesions of the spinal pathways or signs of encephalitis or meningitis. The affected motor fibers of the upper limbs were electrically inexcitable, but sensory findings were normal. Electromyography of the paralyzed muscles revealed pathological denervation activity without voluntary activation. The initial magnetic resonance imaging (MRI) showed a large hyperdense lesion in the anterior part of the cervical cord from C3 to T1. Despite the fact that MRI changes disappeared completely within 6 weeks the patient showed only little improvement in the paralyzed muscles after 6 months. To our knowledge, these MRI changes in patients with tick-borne encephalitis, consistent with an isolated anterior horn lesion, have never been reported previously. The course may have been aggravated by an initial antibiotic treatment with cephalosporins.

Adult↗
PubMed1999

Metalloproteinase-mediated release of the ectodomain of L1 adhesion molecule.

The L1 adhesion molecule is an approx. 200-220 kDa type I membrane glycoprotein belonging to the immunoglobulin (Ig) superfamily. L1 can bind in a homotypic fashion and was shown to support integrin-mediated binding via RGDs in the 6th Ig-like domain. In addition to its cell-surface expression, L1 can occur in the extracellular matrix (ECM). Here we demonstrate that L1 is constitutively released from the cell surface by membrane-proximal cleavage. L1 shed from B16F10 melanoma cells remains intact and can serve as substrate for integrin-mediated cell adhesion and migration. The release of L1 occurs in mouse and human cells and is blocked by the metalloproteinase inhibitor TAPI (Immunex compound 3). This compound has been shown previously to block release of L-selectin and TNF-alpha which is mediated by the membrane-bound metalloproteinase TNF-alpha converting enzyme (TACE). Using CHO cells that are low in TACE expression and do not release L-selectin we demonstrate that L1 release is distinct from L-selectin shedding. We propose that cell-surface release may be necessary for the conversion of L1 from a membrane into an ECM protein.

Animals↗
PubMed1998

[Leg pain--the contribution of the neurologist].

Pain syndromes in the lower limbs are a particular challenge for the clinical neurologist. Pain may be due to various disorders of the central and peripheral nervous system or muscles of different etiologies. There is a continuum from slightly unpleasant sensory disturbances to nociception. Differential diagnosis must be sought according to topological and pathophysiological interpretation of the clinical findings. This will determine the necessary diagnostic requirements and therapeutic procedures. Within the central nervous system lesions of the nociceptive projections of the spinal cord or brain may lead to pain in the lower limbs. Furthermore, different pathologies of the peripheral nervous system (root, plexus, peripheral nerve) or muscles can cause pain. Finally, pain syndromes are known in clinical syndromes with disturbances of the muscle tone (extrapyramidal syndromes, spasticity) and secondary to postural problems in patients with muscular dysbalance due to paralysis.

Diagnosis, Differential↗
PubMed1997

[Conservative therapy in thoracic outlet syndrome. Literature review and pathogenetic considerations].

Due to the broad clinical presentation and the lack of generally accepted diagnostic criteria, thoracic outlet syndrome (TOS) is a disputed diagnosis. Various surgical techniques have been described and investigated as treatment for TOS, whereas only a few studies have reported the outcome after a conservative approach. Based on the literature, the pathophysiology of TOS and the impact of conservative therapy are discussed. Our personal experience has shown that after early diagnosis and implementation this treatment is a safe and valuable therapeutical option in TOS based on the correction of a postural and functional disturbance of the upper thoracic aperture underlying the pathogenic process. Successful conservative treatment may also be considered as further diagnostic evidence for TOS.

Adult↗
PubMed1997

Cortico-bulbar fibers to orofacial muscles: recordings with enoral surface electrodes.

A new recording technique was developed to eliminate current problems on recording transcranial evoked facial muscle responses. A fork-shaped device equipped with 2 pairs of Ag/AgCl-electrodes was inserted enorally at the buccinator muscle level. Advantages offered by this method comprise clearly defined negative deflection of the compound muscle action potential, lack of relevant volume conduction from adjacent muscles, reliability of amplitude criteria, absence of interfering stimulus artifacts, easy achievement of preactivation, and noninvasive recording by surface electrodes. In 43 healthy subjects transcranial magnetic stimulation evoked contralateral responses at a mean latency and mean amplitude of 10.3 +/- 1.1 ms and 1.6 +/- 1.1 mV, respectively on the right side of the face and of 9.9 +/- 1.0 ms and 1.6 +/- 1.1 mV, on the left side of the face. Ipsilateral cortical evoked responses were observed in 29 and 25 subjects (left and right side of the face) at a mean latency and amplitude of 10.7 +/- 2.5 ms and 0.8 +/- 0.5 mV, respectively on the left side of face and of 11.9 +/- 3.2 ms and 1.1 +/- 1.2 mV, on the right side of face. No responses were obtained in 2 and 4 subjects (left and right side of the face), and could not be assessed due to simultaneous facial nerve stimulation in 12 and 14 subjects (left and right side of the face).

Adolescent↗
PubMed1996

The perception of movements elicited by magnetic cortex stimulation depends on the site of stimulation.

Previous reports suggest that magnetic cortical stimulation (MCS) of the motor cortex can elicit a sensation of movement (kinaesthesia) in paralysed limbs. To assess this sensory effect of MCS, we examined the accuracy of kinaesthetic perception of stimulus-induced right elbow flexion in six blindfolded, healthy subjects. Matching of movements elicited by MCS was compared with matching of passive elbow movements. Small flexion movements between 1.5 and 5 degrees of angle were regularly overestimated by 50-100% when induced by MCS over the parietal cortex, whereas movements elicited by MCS over the frontal cortex or by passive elbow flexion were accurately estimated. Our results provide data compatible with the hypothesis of the existence of a "central sense of movement". Activation of collateral branches projecting from the motor cortex to the sensory could be the underlying mechanism to this phenomenon.

Adult↗
PubMed1995

Diagnostic value of paraclinical tests in multiple sclerosis: relative sensitivities and specificities for reclassification according to the Poser committee criteria.

The yield of paraclinical tests was evaluated in a prospective study of 189 consecutive patients referred for suspected multiple sclerosis (142 patients with multiple sclerosis, 47 non-multiple sclerosis patients on discharge). Patients were first classified according to the Poser criteria by the clinical findings. Subsequently, the results of paraclinical tests (cranial MRI, visually evoked potentials (VEPs), somatosensory evoked potentials by tibial nerve stimulation (SSEPs), motor evoked potentials (MEPs), and analysis of CSF for oligoclonal banding and IgG-index (CSF)) were taken into account. The percentage of reclassified patients (reclassification sensitivity, RS) was always lower than the percentage of abnormal results (diagnostic sensitivity, DS), and the divergence of RS v DS differed between the tests (60% v 84% in MRI, 31% v 77% in CSF, 29% v 37% in VEPs, 20% v 68% in MEPs, and 12% v 46% in SSEPs respectively). False reclassifications of non-multiple sclerosis patients to multiple sclerosis would have occurred with all tests (MRI: six of 47 patients, (reclassification specificity 88%); CSF: one (98%); VEPs: two (96%); MEPs: two (96%); SSEPs: four (91%); P < 0.05). Although MRI had superior diagnostic capacity, 57 of the 142 patients with multiple sclerosis were not reclassified by the MRI result, 12 of whom were reclassified by CSF and 18 by one of the evoked potential (EP) studies. Of the 98 patients not reclassified by CSF, 53 were reclassified by MRI and 39 by EPs. The results suggest that for the evaluation of paraclinical tests in suspected multiple sclerosis, comparison of diagnostic sensitivities is inappropriate. In general, a cranial MRI contributes most to the diagnosis; however, due to its comparatively low specificity and its considerable number of negative results, EP or CSF studies are often useful to establish the diagnosis of multiple sclerosis.

Adolescent↗
PubMed1995

[Serodiagnosis of atypical bacterial respiratory infections].

Since prevalence of antibodies to bacteria causing atypical respiratory infections in Israel is as yet unknown, a 5-year antibody prevalence study was performed. Seroreactivity to Chlamydia pneumoniae (TWAR), with titers > or = 1:16 by microimmunofluorescence assay (MIF) was detected in 725/1305 (55.5%) of patients. 47/1012 ((4.6%) of adult patients had MIF results indicating recent infection with TWAR, (IgG titers of > or = 1:512, and/or IgM titers of > or = 1:16, and/or seroconversion). Antibody prevalence and titers were low in children aged 1-10 years, increased in teenagers, and peaked in adults and the elderly, in whom prevalence was up to 79% and mean geometric titer up to 1:163. Unlike the consistency in TWAR antibody prevalence and serological evidence of recent infection during the study period, a significant decrease in those variables was observed for Chlamydia trachomatis during the first 3 study years. Antibodies to M. pneumoniae were detected in 53 and to Legionella sp. in 47 out of 763 patients. There was serological evidence of recent infection with M. pneumoniae in 10 (including 7 children) and with Legionellae in 8. Improved diagnosis of atypical respiratory infection might be achieved by the combined use of these proposed serological procedures.

Adolescent↗
PubMed1994

Prevalence of Chlamydia pneumoniae antibodies in patients with acute respiratory infections in Israel.

AIMS: To evaluate the prevalence of antibodies to Chlamydia pneumoniae (TWAR) in relation to other aetiological agents of acute respiratory infections in Israeli patients. METHOD: Serum samples from 604 patients (183 children and 421 adults) were collected over three years. Antibodies to C pneumoniae, C trachomatis, and Legionella sp were evaluated using the microimmunofluorescence (MIF) assay. Antibodies to Mycoplasma pneumoniae were detected using the Serodia Myco II test. RESULTS: Antibodies to TWAR were detected in 319 (51.3%) sera. Twenty one patients had MIF results indicative of recent infection. TWAR prevalence and antibody titres in children (aged 1-10 years) were low, gradually increased in teenagers (11-18 years), and were highest in adults and elderly patients. In contrast to the consistently noted TWAR antibody prevalence and serological evidence of recent infection during the study period, a significant decrease in those variables was recorded for C trachomatis. Six patients had serological evidence of recent infection with both C pneumoniae and C trachomatis. The presence of antibodies to Mycoplasma pneumoniae and Legionella sp was tested in 473 of the patients; 29 had antibodies to M pneumoniae and 23 to Legionella sp. Six patients (including five children) had serological evidence of recent infection with M pneumoniae and four with Legionella sp. CONCLUSION: C pneumoniae should be considered in patients with acute respiratory diseases. MIF is the preferred method for monitoring the presence of antibodies to this organism.

Acute Disease↗
PubMed1994

High prevalence of multiple sclerosis in Switzerland.

Prevalence of multiple sclerosis (MS) was determined in the Canton of Berne, Switzerland. This canton is a geographically diverse region at 47 degrees northern latitude with 920,000 inhabitants. Epidemiological data were obtained from the case records of the University Department of Neurology, from the Swiss MS Society, from practising neurologists and from regional hospitals. Diagnostic accuracy was ascertained in retrospect, and only those cases fulfilling the criteria proposed by the Poser Committee were included. Of the patients provided by the Swiss MS Society, only those who had been diagnosed by a neurologist were accepted as definite cases. Changes of population due to migration or death were traced at governmental registry offices, and the place of residence was determined. Using the 1,016 cases of definite and probable MS identified, the minimal prevalence rate was 110 MS cases/100,000 inhabitants in the Canton of Berne on January 1, 1986. The increase in MS in this region since the 1950s was due mainly to the increase in life duration of MS patients rather than an increase in incidence rates over the last 20 years.

Adolescent↗
PubMed1994

A membrane-located polypeptide of Ulva sp. which may be involved in HCO3- uptake is recognized by antibodies raised against the human red-blood-cell anion-exchange protein.

Polypeptides present in a membrane fraction of the marine macroalga Ulva sp. were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tested for cross-reactivity with antibodies raised against the human red-blood-cell anion exchanger (AE1). A polypeptide of ca. 95 kDa was identified with a monoclonal, as well as two polyclonal (one against the C-terminus and one against the whole protein) antibodies, indicating that it shares homologous domains with AE1. These findings complement an earlier study which indicated that a plasmalemma-bound, disulfonic stilbene-sensitive, protein was functionally involved in HCO3- transport into the photosynthesizing cells of Ulva (Z. Drechsler et al. 1993, Planta 191, 34-40). It is thus suggested here that a similar protein has evolved, and has been conserved, in marine photosynthetic organisms and mammalian red blood cells for the purpose of HCO3- transport.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1992

Tomographic myocardial perfusion imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia: correlation with thallium-201 imaging.

Single-photon emission computed tomographic imaging with technetium-99m teboroxime during exercise has been found to be feasible and the results correlate with those obtained with thallium-201. This study examined the feasibility of this technique and compared tomographic imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia with thallium-201 imaging. With the patient positioned on the imaging table, adenosine was infused at a rate of 140 micrograms/kg per min for 6 min. At 4 min, 20 to 25 mCi (740 to 925 MBq) of technetium-99m teboroxime was injected intravenously and imaging was started as soon as the infusion was completed with use of a 180 degrees anterior arc and 32 stops at 10 s/stop (total imaging time 7.8 min). Rest images were obtained 60 to 90 min later with use of a similar dose of technetium-99m teboroxime. Exercise tomographic thallium images were obtained within 2 weeks of the teboroxime studies. In the 20 patients studied, the teboroxime images were normal in 2 (50%) of 4 normal subjects and abnormal in 15 (94%) of 16 patients with coronary artery disease; 4 of the 15 had a fixed defect and 11 a reversible defect. There was agreement between teboroxime and thallium studies in 16 patients (80%), in 319 (80%) of 400 segments and in 50 (83%) of 60 vascular segments (p less than 0.05). In two normal subjects, an apparent fixed defect involving the inferior wall was seen on the teboroxime but not the thallium images and was thought to be due to an attenuation artifact secondary to extracardiac activity in the left lobe of the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1991

[Steroid therapy in multiple sclerosis].

Since the 1950s steroids have been known to have a beneficial effect on recovery from acute exacerbations of multiple sclerosis. The main effect is a more rapid improvement after acute relapses due to resolution of edema in the central nervous system. Long-term steroid therapy showed no benefit in patients with a progressive course and involves dangerous side effects (Cushing's habitus, hyperglycemia, increased susceptibility to infections, peptic ulcers, osteoporosis, cataract). Intrathecal steroid administration offered no advantage over the conventional i.v. route. On the basis of a multicentre trial, ACTH therapy became the standard regime in the treatment of acute exacerbations. Recent reports have demonstrated a beneficial effect of therapy with high-dose methylprednisolone. Taking into account the restrictions and possible side effects, this therapy is a safe and efficient alternative to the standard ACTH regimen in the treatment of acute exacerbations in multiple sclerosis.

Adrenocorticotropic Hormone↗
PubMed1991

[Sequelae of severe craniocerebral injuries. An epidemiological study in the Canton of St. Gallen].

Severe head injuries often lead to serious medical and socioeconomic sequelae. The incidence rate indicated in other studies shows a wide variation due to differences in selection criteria. Based upon an unselected population, the incidence of severe head injury was calculated and the surviving patients were interviewed and clinically examined 3 years after the accident in order to describe the course, rehabilitation and psychosocial sequelae after severe head injury. Retrospectively we collected 80 patients living in the canton of St. Gallen who had a severe head injury requiring hospitalization in 1987, indicating an incidence of 20 per 100,000 inhabitants. 22 (28%) of these patients died as a consequence of the head trauma. The best predictor was the Glasgow coma score at admission, which showed a highly significant direct correlation with survival rate. Regarding the degree of impairment of survivors the duration of posttraumatic amnesia was the best predictive parameter. Of the 45 patients controlled 3 years after the head trauma only 11% were severely impaired in daily activities. 79% of the patients who were gainfully employed before the accident were working full- or at least part-time. However, only 3 patients (7%) were absolutely free of symptoms. Most patients suffered from cognitive and emotional deficits. Based on an estimated incidence for minor head trauma of 174 per 100,000 inhabitants, a total annual incidence for all head traumas of 194 per 100,000 inhabitants is calculated, with severe head injury representing about 1/9 of all head injuries.

Adolescent↗