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Biomedical subjects

T Ganes

Publications and source records attributed to T Ganes.

At least 37 records · Page 2Linked to original sources
PubMed1986

Multimodal evoked responses and cerebrospinal fluid oligoclonal immunoglobulins in patients with multiple sclerosis.

One hundred patients with possible, probable and definite multiple sclerosis (MS) were examined with somatosensory (SER), visual (VER) and brain stem auditory (BAER) evoked responses. Paired samples of cerebrospinal fluid (CSF) and serum were examined with agarose gel electrophoresis to detect intrathecally synthesized oligoclonal immunoglobin bands. Comparison of the number of abnormal CSF and evoked response tests showed that the CSF examination was slightly more sensitive in all diagnostic groups when compared to the results of multimodal evoked responses but that the two sets of test were in part supplementary. Oligoclonal immunoglobulin bands in the CSF were present in all patients with a duration of the disease of less than six months. VER seemed to be the most sensitive of the evoked tests in this particular group of patients.

Brain Stem↗
PubMed1985

Functional cervical myelography with iohexol.

Thirty patients underwent functional cervical myelography, i.e. radiographs in the lateral view were obtained in extension as well as in flexion of the neck. Sagittal tomography was performed in both positions. Widening of the subarachnoid space and decreased sagittal diameter of the spinal cord due to shortening were demonstrated in the lateral view in flexion. In some cases with advanced narrowing or spinal block in extension, such widening in flexion resulted in better diagnostic images by providing passage of the contrast medium caudally. Although iohexol (Omnipaque, Nyegaard & Co., Oslo) was regularly forced into the posterior cranial fossa by the movements, the frequency of side effects was approximately the same as in our former trials with iohexol in conventional cervical myelography. EEG changes occurred in two patients (7%). A sitting position for 3-4 min after the examination followed by an elevated head end of the bed was probably important for preventing side effects from the contrast medium. Specific questioning revealed twice as many subjective side effects as reported after general questions alone.

Adult↗
PubMed1985

Combined renal and pancreatic transplantation: effects on advanced diabetic neuropathy and retinopathy.

In this study of 24 uremic diabetic patients treated with combined kidney and pancreas transplantation, the one year patient, kidney and pancreas graft survival was 96, 78 and 55%, respectively. In recipients followed for three months or more, a regression of neuropathy was registered in all patients, whereas improvement in visual acuity was seen only in two patients with simplex type retinopathy. The advanced proliferative retinopathy observed in most recipients at the time of transplantation, was not significantly altered after pancreas and kidney transplantation.

Adult↗
PubMed1984

Cervical myelography with iohexol.

An open study with iohexol (Omnipaque) in cervical myelography has been performed in 20 patients to evaluate the properties and neurotoxicity of this new water soluble contrast medium. The image quality was good (30%) or excellent (70%) in all cases. The frequency of headache was 25%. No EEG changes were severe and the total frequency was 20%. We conclude that this study supports other reports of iohexol having a low neurotoxicity and is well suited for intrathecal use.

Adult↗
PubMed1984

Iohexol compared to metrizamide in cervical and thoracic myelography. A randomized double blind parallel study.

A randomized double blind study with iohexol (Omnipaque) and metrizamide (Amipaque) in cervical myelography was performed in 50 patients, 29 with iohexol and 21 with metrizamide. The myelographies were performed either with lumbar or with C1-C2 puncture in about equal groups, using 300 mg I/ml and 240 mg I/ml of the contrast media respectively. The image quality was equal with both contrast media, excellent in about 4/5 and good in 1/5 of the examinations. Subjective side effects were twice as frequent with metrizamide as with iohexol. The most frequent side effect was headache, occurring in 34% with iohexol and in 67% with metrizamide. Altogether 24% or the patients had EEG changes after iohexol as compared to 47% after metrizamide. All EEG changes were slight dysrythmia-except in three patients with spike activity after metrizamide. These were the only ones with mental reactions as well. It can be concluded that in this trial iohexol was better suited for cervical myelography than metrizamide.

Adult↗
PubMed1984

Subcomponents of the cervical evoked response in patients with intracerebral circulatory arrest.

The subcomponents of the cervical evoked response, N11, N13, N14, and the following positivity, were studied in 13 patients with full arrest of the intracerebral circulation, isoelectric EEGs and abolished cortical somatosensory evoked responses. The peak negativity (N13) and the following positive wave were present in all patients. Also N11 and N14 could be identified in most patients either at standard stimulation frequency (2 Hz) or by increasing the stimulation rate. The results point to a spinal origin of these sub-components in the human cervical evoked response.

Adolescent↗
PubMed1983

The effect of thiopentone on somatosensory evoked responses and EEGs in comatose patients.

EEGs and somatosensory evoked responses from the brachial plexus, neck and scalp were recorded in seven comatose patients on continuous thiopentone infusion. Although pathological in five of the patients, the evoked responses were present in all. Additional amounts of thiopentone producing a full suppression of all spontaneous EEG activity had no effects either on the configuration of the evoked responses or on the central conduction times. This resistance of the somatosensory evoked responses to a deep and sustained thiopentone narcosis makes it a useful test in comatose patients receiving this treatment.

Adolescent↗
PubMed1983

Induced barbiturate coma: methods for evaluation of patients.

Seven patients treated with deep sustained barbiturate narcosis to protect the brain and control intracranial hypertension underwent extensive monitoring. The epidural intracranial pressure (EDP) and arterial blood pressure (BP) were recorded continuously; serial records of the EEG, somatosensory evoked potential (SEP) and internal carotid artery (ICA) flow velocities by pulsed Doppler technique were obtained. Serum barbiturate levels leading to full suppression of the EEG did not change the central conduction time nor the configuration of the evoked responses. Monitoring the intracranial pressure (ICP), BP, and thereby, the cerebral perfusion pressure (CPP) gave valuable information on the patients' state and served as a guide for dosage and timing of barbiturate therapy, and facilitated supervision of adequate ventilation. Recording of EEG and SEP, monitoring of the CPP and ICA Doppler investigation offer prognostic information in these cases. When clinical deterioration occurs, these methods can predict and, in combination, give ample evidence for development of brain tamponade. Premature as well as unnecessarily deferred 4-vessel angiography, therefore, can be avoided.

Barbiturates↗
PubMed1982

Distribution of GABA sensitive areas on hippocampal pyramidal cells.

In isolated transverse hippocampal slices GABA (gamma-amino-butyric acid) was applied iontophoretically to various parts of the dendritic tree of CA1 pyramidal cells. Indices of GABA effects were reduced amplitude of orthodromically driven CA1 population spikes and inhibition of single CA1 units driven by orthodromic stimulation or by application of L-glutamate. Weak iontophoretic currents of GABA (3-6 nA, backing current -3 nA) effectively reduced the amplitude of the population spike and arrested unit activity when applied in a position close to the soma. The effect was halved when GABA was applied 25-30 micrometer away at right angles to the main dendritic axis. In the direction of the main dendritic axis, GABA was affective as far as 250 and 150 micrometer from the soma in the apical and basal dendritic directions, respectively, corresponding to about 50% of the total dendritic length. The best effect was usually found at a depth corresponding to that of the recording electrode, probably because the main dendritic axis was parallel to the slice surface. The sharp localization of GABA sensitivity when applied in the pyramidal layer supports earlier evidence that GABA mediates the basket cell inhibition on the soma of the pyramidal hippocampal cells. In the dendritic tree, GABA may also have an inhibitory function with an effectiveness matching that of the soma application.

Animals↗
PubMed1982

Synaptic and non-synaptic components of the human cervical evoked response.

The human cervical evoked response comprises a main negative wave and a following positivity. The peak of the negative wave, N13, is preceded by a small notch, N11, on the ascending negativity and is followed by another notch, N14, on the descending negative slope. The mechanisms of the components in the human cervical evoked response are still subject to discussion. In the present study conventional neurophysiological techniques were applied to see whether the components were of synaptic or non-synaptic origin. Resistance to high-frequency stimulation, refractoriness as tested by train or double shock conditioning stimuli and the effect of graded stimulation revealed that N11 and N14 fulfilled the criteria of a non-synaptic origin. N13 and the positive wave had properties pointing to a synaptic origin, the latter evidently reflecting an inhibitory mechanism. Each component in the human cervical evoked response both morphologically and functionally resembled the well known subcomponents in the spinal cord dorsum potential in experimental animals.

Brachial Plexus↗
PubMed1981

Non corneal closed eye electroretinography in healthy persons and in patients with neuronal ceroid lipofuscinosis (Stengel-Batten-Spielmeyer-Vogt disease).

Non corneal "closed eye" ERG was recorded with surface skin electrodes in 22 healthy subjects and in 7 patients with neuronal ceroid lipofuscinosis (Stengel-Batten-Spielmeyer-Vogt disease). Non corneal "closed eye" ERG was present in all normal subjects and the records comprised all the main subcomponents reported in the conventional corneal ERG. While the latencies of the a and b waves in the normal subjects differed but slightly from those reported from corneal ERGs, the amplitudes were reduced in the non corneal "closed eye" ERG. The parameters of the non corneal "closed eye" ERGs in the healthy subjects differed but slightly from those reported on non corneal "open eye" ERGs. When applied on patients with neuronal ceroid lipofuscinosis, the method proved clinically tenable and no sedation was required. The records show that ERG was absent in all but one of the patients tested.

Adolescent↗
PubMed1980

A study of peripheral cervical and cortical evoked potentials and afferent conduction times in the somatosensory pathway.

Somatosensory evoked potentials were recorded from Erb's point (N9), the cervical spine (N14) and the scalp (N20) in 47 volunteer patients to establish the normal impulse conduction time between these recording sites. Either the ulnar or the median nerve or both were stimulated percutaneously, and pure sensory as well as mixed sensorimotor nerve fibres were used. No significant differences in either the N9-N14 or N14-N20 conduction times were found for different sets of peripheral stimuli. The N9-N14 conduction time evidently reflects impulse propagation in the proximal part of the brachial plexus, the cervical roots and the dorsal column. Cross-correlation analysis, however, suggested that the main contribution to this conduction time is a central one, probably the dorsal column. The N14-N20 conduction time represents a pure central conduction time probably between the dorsal column nuclei and the cortex. While the amplitudes, morphologies and latencies of the somatosensory evoked responses N9, N14 and N20 varied significantly, the N9-N14 and N14-N20 conduction times were fairly constant. The results indicate that diagnostic use of the somatosensory evoked potentials based exclusively on the response latencies can be very misleading, both when latencies are normal and when pathologically delayed. In such cases the N9-N14 and N14-N20 conduction times can be conclusive, and we suggest that these times should be included in all SEP tests.

Adolescent↗
PubMed1980

Somatosensory evoked responses and central afferent conduction times in patients with multiple sclerosis.

Evoked responses following median nerve stimulation were recorded from Erb's point, the cervical spine and the scalp and afferent conduction times between each recording point were determined in 44 patients with multiple sclerosis. A prolonged central conduction time was frequently the only finding in MS patients, particularly in the early stages of the disease. Changes in central conduction time thus seem to be more sensitive than changes either in response latencies or response morphology.

Adult↗
PubMed1980

Somatosensory conduction times and peripheral, cervical and cortical evoked potentials in patients with cervical spondylosis.

Peripheral, cervical and cortical somatosensory evoked potentials after median or ulnar nerve stimulation were recorded in 21 patients with cervical spondylosis with radiculopathy or myelopathy. The test was normal when pain and paraesthesias were the only symptoms, while pathological in radiculopathy with objective neurological signs. The results varied in patients with cervical myelopathy.

Adult↗
PubMed1978

Effect of carbamazepine, phenytoin and phenobarbitone on serum levels of thyroid hormones and thyrotropin in humans.

Patients on long-term treatment with either of the stereochemically related antiepileptic drugs phenytoin (DPH) or carbamazepine (CBZ) had similar changes in serum thyroid hormone concentrations. T4, FT4, FT4 index, T3, FT3, FT3 index and rT3 were reduced, whereas T3U and TSH were not significantly different from the reference group levels. Long-term phenobarbitone treatment had no convincing effect on the investigated parameters when used alone, but possibly potentiated the effect of CBZ. In patients starting on CBZ, T4 fell to a stable 70% of the basal level after 1--2 weeks. T3 decreased transitorily to 85% of the basal level. TSH showed a complementary but somewhat delayed transitory increase. T3U and TBG did not change significantly. The effect of CBZ and DPH can be explained by interference with thyroid hormone binding to TBG combined with enzyme-induced increased metabolic clearance rate of thyroid hormones without homeostatic maintenance of premedication levels of FT4 and FT3. We suggest that the regulated factor maintaining euthyroidism in these patients is the total quantity of thyroid hormones being degraded in the tissues per unit time. We conclude that serum concentrations of FT4 and FT3 do not reflect thyroid status adequately under all circumstances.

Adult↗