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Biomedical subjects

T Sand

Publications and source records attributed to T Sand.

At least 91 records · Page 5Linked to original sources

Hyperventilation syndrome: clinical, ventilatory, and personality characteristics as observed in neurological practice.

The symptoms of the hyperventilation syndrome (HVS) are sometimes diffuse, and HVS may resemble other clinical conditions. A diagnosis of HVS was made in 25 patients referred for neurological assessment because of atypical, shortlasting, episodic complaints. The referral diagnoses varied within a wide range. A need for more indepth knowledge about this group of patients thus arose. During a provocation test with forced respiration, all patients reported symptoms similar to those during attacks. Eight patients described numbness or paraesthesias with unilateral predominance. End-tidal pCO2 levels were monitored prior to and during a forced hyperventilation test. Compared with controls, the patients had significantly decreased end-tidal pCO2 even during symptom free periods. After hyperventilation, hypocapnia followed a protracted course in the patient group. Sensory symptoms may be asymmetric and mimic focal cerebral disease. Strained respiration may be denied during spontaneous attacks. Personality characteristics were evaluated with the Minnesota Multiphasic Personality Inventory (MMPI). A mean group profile very similar to profiles reported on "pseudoepileptic" patients was found. The profile indicates a neurotic pattern where patients tend to respond to psychological stress with somatic symptoms.

Adolescent↗

Evoked potentials and CSF-immunoglobulins in MS: relationship to disease duration, disability, and functional status.

In 100 MS patients, BAEP and tibial SEP abnormality rates increased significantly with disease duration and clinical disability. VEP correlated non-linearly with disease duration, and median nerve SEP correlated with disability. In multifactorial analysis, however, BAEP correlated significantly only with clinical brainstem and cerebellar signs. These results suggest that evoked potentials correlate more strongly with neurological status of the functional subsystems than either overall disability or disease duration. These findings indirectly suggest that evoked potentials may be useful monitors during large therapeutical trials in MS patients.

Adolescent↗

Statistical properties of ABR amplitudes and latencies. Implications for computation of reference limits and relation to click phase.

A method for statistical analysis and computation of reference limits for ABR latency and amplitude variables is presented. Condensation and rarefaction ABRs from 47 healthy controls aged 4-58 years were investigated. With respect to gaussianity of distributions, the square root transformation was superior to the logarithmic transformation for amplitudes, while the logarithmic transformation performed better for amplitude ratios. Wave V latency and the I-V interpeak latency were nearly normally distributed, while other latencies and inter-peak latencies displayed varying displacement from a normal distribution. Rarefaction ABR distributions were slightly closer to normality than were condensation ABRs. Amplitude vs. following amplitude and latency vs. amplitude correlation coefficients were larger for R than for C click ABRs; thus R clicks seem to evoke a better synchronized neural volley. Most of the correlation between amplitude and latency could be explained by the influence of age and sex. Hence, age and sex matched reference limits for ABR amplitudes, without correction for latency, seem to be adequate in practical clinical work.

Acoustics↗

Side effects after ambulatory lumbar iohexol myelography.

Side effect incidences after ambulatory (22G needle and two h bed rest) and after non-ambulatory (22 and 20G needles and 20 h bed rest) lumbar iohexol myelography have been estimated and compared. Headache incidence was significantly greater in ambulatory (50%, n = 107) as compared to non-ambulatory myelography (26%, n = 58). Headaches in the ambulatory group tended to be of shorter duration and the difference between severe headaches in ambulatory and non-ambulatory groups was not significant. Serious adverse reactions did not occur and none of the ambulatory patients required readmission because of side effects. The headache was predominantly postural and occurred significantly earlier in the ambulatory group. Headache incidence was significantly greater after 20G needle myelography (44%, n = 97) as compared to 22G needle iohexol myelography (26%, n = 58). The results supports the hypothesis that CSF leakage is a major cause of headache after lumbar iohexol myelography.

Adult↗

Which factors affect reported headache incidences after lumbar myelography? A statistical analysis of publications in the literature.

Nineteen publications were reviewed and subjected to a combined statistical analysis (meta-analysis) regarding the influence of study design factors upon reported headache and total symptom incidences after lumbar iohexol myelography. A significant association was found between reported side effects on one hand and needle diameter, follow up time and the method of questioning respectively on the other. The combination of long follow-up time and specific questioning and the combination between larger diameter (20G) needles and long follow-up time, both seemed to be strong predictors for reporting high side effect incidences. Nine studies were similarly analyzed regarding the influence of early ambulation and contrast type upon reported headache incidences. Early ambulation significantly increased headache after iohexol or iopamidol lumbar myelography as opposed to metrizamide myelography.

Early Ambulation↗

Unilaterality of headache in classic migraine.

The localization of a headache is a matter of importance for the diagnosis. Migraine is considered to be a unilateral headache. There is, however, only limited information available on the constancy of the unilaterality: how frequently is the pain locked to one side? This aspect is of importance in the differential diagnosis vs. cervicogenic headache, where the pain persistently seems to occur on the one side. In the present study, 31 cases (26F, 5M with a mean age of 40 years; range: 17-63) with a diagnosis of classic migraine were questioned with regard to laterality of headache at the first consultation. A unilaterality as such was present in 42%; unilaterality alternated with bilaterality in 42% of the cases; unilaterality in some form was therefore found in 84% of the cases. In classic migraine, unilaterality thus seems to outweigh bilaterality. In every case of unilaterality there was a sideshift. A side-locked unilaterality thus seems to be a rare phenomenon in classic migraine. These patients were followed-up after between 3 and 9 years; they then filled in a questionnaire (response rate: 81%). The consistency between the two sets of information in the responders was good. Only one case (possibly two) showed a side-locked unilaterality at the time of the questionnaire.

Functional Laterality↗

Cluster headache: pupillometric patterns as a function of the degree of anisocoria.

Fifty-three patients with cluster headache, mean age 42.6 years, were examined by means of pupillometry. Pharmacological stimulation was carried out by the instillation of eye drops; the sympathomimetic agents hydroxyamphetamine (a norepinephrine releaser) and phenylephrine (an agent acting directly on the postsynaptic receptors) were applied. Pupillary dilatation was measured at set time intervals, comparing the responses of the symptomatic and non-symptomatic sides. The material was divided into groups according to the degree of basal anisocoria. The subgroup with the most pronounced basal miosis of the symptomatic side demonstrated a uniform pattern of deficient symptomatic side dilatation after OH-amphetamine and supersensitivity to phenylephrine. The other groups demonstrated the same general pattern, but to a far lesser degree. In cluster headache, the extent of nonresponsiveness to OH-amphetamine and of phenylephrine supersensitivity on the symptomatic side thus, at least partly, seems to be a function of the degree of anisocoria. The response pattern in cluster headache seems to differ from that of 3rd neuron Horner's syndrome with an anisocoria of the same extent.

Adult↗

Inosine causing insulin release and increased myocardial uptake of carbohydrates relative to free fatty acids in dogs.

The aim of the present study was to determine the effect of i.v. inosine on myocardial substrate uptake and function in the in situ dog heart. Inosine was infused i.v. at a rate of 5 mg kg min-1 in eight closed-chest pentobarbital anaesthetized dogs. Inosine caused a 46% decrease (P less than 0.01) in plasma free fatty acids (FFA), a 15% decrease (P less than 0.05) in plasma glycerol, an 18% decrease (P less than 0.05) in plasma glucose and a 46% increase (P less than 0.01) in blood lactate. This was associated with a 55% decrease (P less than 0.01) in myocardial FFA uptake and a 72% increase in lactate uptake, while glucose uptake remained unchanged. These metabolic changes were associated with a five-fold increase (P less than 0.05) in arterial insulin. Inosine caused an 18% increase (P less than 0.01) in myocardial blood flow without changing MVO2. There was a 33% increase (P less than 0.01) in LV dP/dtmax, a decrease in LVEDP from 4.9 +/- 0.9 (mean +/- SEM) to 0.9 +/- 0.3 mmHg (P less than 0.05) and a 24% decrease (P less than 0.01) in systemic vascular resistance. Inosine caused a transient 38% increase (P less than 0.05) in pulmonary vascular resistance. In conclusion, in addition to a positive inotropic effect and vascular effects inosine was found to cause release of insulin and to shift myocardial metabolism towards increased uptake of carbohydrates relative to FFA.

Animals↗

F-responses after metrizamide and iohexol lumbar myelography.

We measured several F- and averaged F-response variables before and after lumbar myelography with metrizamide and iohexol in order to evaluate possible effects of these contrast agents upon proximal motor nerve conduction and motor neurone exitability. Averaged F-response onset latency increased while both duration and amplitude decreased after iohexol myelography. These changes were interpreted as signs of minor neural depression but they were slight and without clinical significance in the individual patient. F-response variables were not affected after metrizamide myelography.

Electromyography↗

Cluster headache: combined assessment with pupillometry and evaporimetry.

Twenty-nine patients with cluster headache have been examined with the pupillometer and the evaporimeter. Pupils were dilated by sympathicomimetic drugs instilled into the conjunctival sacs, and responses of the two sides were compared. Forehead sweating was stimulated by body heating and by pilocarpine injection, and sweat evaporation on the two sides was compared. Most patients demonstrated the known patterns of hyposecretion on heating, of pilocarpine supersensitivity, and of deficient pupillary dilatation on OH-amphetamine stimulation on the symptomatic side and a supersensitivity of this pupil to phenylephrine. There were deviations from the rule for all methods of testing. Sixteen patients demonstrated a typical supersensitivity response of the pupil and of the sweat glands on the symptomatic side. Six patients had no such response, and seven patients had a discrepancy between the pupillary and the sweat gland response to stimulation, supersensitivity being present in one system only. There was a high degree of concordance between the results of the various methods of examination.

Adult↗

Chronic paroxysmal hemicrania. XIII. The pupillometric pattern.

Pupillometric studies were carried out in eight patients with chronic paroxysmal hemicrania (CPH) and in age- and sex-matched controls in the basal condition and after instillation of 2% tyramine (CPH, n = 5; controls, n = 17), 1% OH-amphetamine (CPH, n = 6; controls, n = 12), and 1% phenylephrine (CPH, n = 6; controls, n = 17). The pupil on the symptomatic and non-symptomatic sides in CPH patients was significantly smaller in the basal condition than in controls, particularly on the symptomatic side. The mydriatic responses to pharmacologic stimulation were essentially similar on the symptomatic and non-symptomatic sides. An evaporimetric study of the forehead sweat glands, using the body heating and pilocarpine tests, was also carried out in these patients and in age- and sex-matched controls. "Early", "intermediate", and "late" measurements demonstrated symmetry of forehead sweating. The findings for both methods of examination thus contrast with those in cluster headache patients. Pupillometric and forehead sweating patterns therefore suggest differences in the pathogenesis of the two headache entities. These tests may be used to distinguish CPH and cluster headache clinically.

Adult↗

Cluster headache: forehead sweating pattern during heating and pilocarpine tests. Variation as a function of time.

Thirty-one patients with cluster headache were examined with regard to their forehead sweating pattern, by means of the Evaporimeter. Sweating was stimulated in two different ways: by body heating and by parenterally administered pilocarpine. The resulting increase in evaporation was frequently measured at different positions on both sides of the forehead, and the possibility of variations in the pattern related to the passage of time was specifically scrutinized. Some typical patterns emerged. The previously reported, marked asymmetries of response (deficient heat-induced sweating and pilocarpine supersensitivity of the symptomatic side) at the medial positions in the forehead were confirmed. However, the asymmetries invariably faded to some extent with the passage of time. Patients with cluster headache show gross similarities with, but also some minor differences from, the sweat pattern of patients with brain stem lesions causing a Horner's syndrome. A subdivision of the material into groups in accordance with the pupillometric pattern after sympathomimetic stimulation made it clear that the cases of definite evaporimetric asymmetries ("typical reactions") belonged to the group with a typical pupillometric pattern. These results suggest that from an "autonomic" point of view, subpopulations may exist within the clinical entity of cluster headache.

Adult↗

Side effects after diagnostic lumbar puncture and lumbar iohexol myelography.

A prospective, controlled study was performed to compare side effect incidences after lumbar iohexol myelography (n = 97) and diagnostic lumbar puncture (n = 85). No significant side effect incidence differences (iohexol vs. controls) were found regarding number of patients with any side effect (63 vs. 73%), headache (44 vs. 54%), nausea, dizziness, visual, auditory, or psychic symptoms. Early-onset headache occurred significantly more often in the iohexol group (17 vs 5%), while postural headache occurred most frequently after lumbar puncture (25 vs. 41%). These results suggest that apart from the slight early-onset headache, most side effects after lumbar iohexol myelography are related to the puncture per se, not to the contrast agent.

Adult↗

Adult manifestation of the Dandy-Walker syndrome. Report of two cases with review of the literature.

Two cases of Dandy-Walker syndrome that became manifest in adult life are reported. A review of the literature of Dandy-Walker syndrome revealed 13 additional cases with onset in adult life and three cases that could not be differentiated from arachnoid cysts. While shunting is the primary treatment in infantile Dandy-Walker, the usual treatment of adult Dandy-Walker has been excision of the membrane covering the enlarged fourth ventricle. The outcome of our two cases treated with membrane excision indicates that primary shunting should also be tried in adult Dandy-Walker.

Adult↗

Appropriate replacement dose of thyroxine in primary hypothyroidism.

An ultrasensitive thyrotropin (TSH) assay was used to determine how many of 65 patients with primary hypothyroidism on thyroxine (T4) replacement therapy had suppressed serum TSH. In 13 patients (20%) TSH levels less than or equal to 0.1 mIU/l were found, indicating an overdose of thyroxine. After correction of the dose, 48 patients had normal TSH values. Their mean dose of thyroxine was 119 micrograms/24 hours, and the appropriate replacement dose tended to decline with advancing age. The serum level of thyroid hormones during replacement therapy with thyroxine very imperfectly reflected serum TSH values. It is concluded that overdose of thyroxine is common when suppressed serum TSH is used as an end point. Biochemical follow-up of replacement therapy with thyroxine in primary hypothyroidism therefore requires the use of an ultrasensitive TSH assay in order to detect such suppression. Serum levels of thyroxine or triiodothyronine (T3) during thyroxine therapy are poor indicators of pituitary TSH secretion and are therefore not useful as parameters of adequate thyroxine dosage.

Adult↗