Biomedical subjects
Publications and source records attributed to T Ganes.
Multimodal-evoked responses and EEG are used as a routine in many intensive care units and have proved their diagnostic and prognostic significance in a series of studies on comatose patients and patients with severe head injuries. The article includes a brief description of the methods, and of their use and interpretation in neurointensive medical care.
Metabolic glucose control was followed in 36 patients at 12-month intervals for up to 5 years after a successful combined kidney and segmental duct-occluded pancreas transplantation. All recipients had normal blood glucose levels at each examination. HbA1 values, intravenous glucose tolerance test, C-peptide levels and C-peptide responses to glucagon stimulation were also, on average, within the normal range. Several individual patients had, however, abnormal values for these parameters. At most 46% had abnormal values for HbA1 and intravenous glucose tolerance test, up to 13% showed low C-peptide values and up to 46% of the stimulated C-peptide responses were inadequate at the different intervals. These parameters did not deteriorate with time. This was true both for the whole group of patients as well as for the 6 patients with a 5-year observation time evaluated separately. Despite these abnormalities in glucose metabolism, all patients remained normoglycaemic without need for exogenous insulin up to 5 years after transplantation. The long-term ability of duct-occluded segmental pancreatic grafts to preserve euglycaemia therefore seems to remain intact at least for 5 years.
The prognosis for patients suffering from fulminant hepatic failure is still poor. The possibility of performing liver transplantation has improved the outcome for the patient. The article presents three cases illustrating some of the difficulties in selecting patients for transplantation, and discusses clinical and laboratory monitoring of patients with fulminant hepatic failure and criteria for selecting patients for liver transplantation.
A randomized double blind crossover test with iohexol and the new non-ionic contrast medium iopentol in 12 patients undergoing carotid angiography showed no difference in tolerability, EEG, ECG, neurologic status or image quality. Iopentol seems to be well suited for cerebral angiography.
The investigation comprised 16 patients with verified myotonic dystrophy. The patients were examined ophthalmologically, by electroretinography (ERG) and pattern visual-evoked potentials (VEPs). The results were compared to those of a normal control group. More than 50% of the patients had changes in their lenses or retinas, and the ERGs and VEPs were frequently abnormal. No statistical relation was found between the clinical and electrophysiological findings, and the pattern of abnormalities seemed to vary at random. The number of abnormal clinical and electrophysiological findings increased slightly with the age of the patients, but no statistically significant relation was found either to the patients' age or the duration of the disease.
Ten patients with an ileoanal anastomosis had conversion to permanent ileostomy 13 (range, 6-29) months after the primary procedure. Causes for reoperation were incontinence in seven patients, unacceptable stool frequency without incontinence in two patients, and atypia in the mucosal remnant with perfect continence in one patient. Stool frequency, continence function, anal canal resting pressure, external anal sphincter (EAS) EMG/pressure relationship (in terms of slope, m), EAS fiber density (FD), and pressure in the distal ileum were registered, and the mucosa and the anal sphincter muscles were examined histologically. There were significant correlations between continence function and EAS changes in terms of both neurophysiologic tests (m and FD) and the histologic picture. The abnormalities in six incontinent patients were consistent with denervation of the EAS. The main reason for fecal leakage in one patient was the high amplitude of pressure waves in the distal ileum. Preservation of mucosal epithelium proximal to the dentate line per se did not seem essential to maintain continence.
EEGs and evoked potentials were recorded in 76 deeply comatose and unresponsive patients with traumatic or non-traumatic cerebral damage. Spontaneous EEG activity was absent in 37 of the patients on the initial examination. The cortical somatosensory evoked potentials were invariably absent in these patients as were the visual evoked potentials. Brain-stem evoked potentials were abnormal, either lacking all waves or with only wave I or II present. Cerebral angiography performed in 33 of the patients within minutes to a few hours after the neurophysiological examination verified an established brain death, showing full intracerebral circulatory arrest in all. Spontaneous EEG activity was initially present in 32 patients on the first examination, 20 of whom had bilaterally abolished cortical somatosensory potentials. Ten of the patients died a few hours after the initial examination, another 10 were followed for 2-3 days and subsequently developed electrocortical silence (ECS). Twelve of the patients with spontaneous EEG activity had preserved cortical somatosensory potentials, either uni- or bilaterally. The only two who survived were found in this group. In the patients followed with multiple recordings over a few days, the first parameter to indicate a grave prognosis was always disappearance of the cortical somatosensory potentials bilaterally, which generally occurred hours, and sometimes a day or two, before cessation of the spontaneous EEG activity. EEG records from 7 patients did not meet the technical criteria of ECS; all, however, had abolished cortical somatosensory potentials bilaterally, and none in this group survived.
EEG, somatosensory (SEP) and visual evoked potentials (VEP) and electroretinography (ERG) were recorded from 16 patients with clinical and electromyographically verified dystrophia myotonica. The results were compared to an age- and sex- matched control group and revealed statistically significant differences between the group mean values for almost all records. Furthermore, abnormal individual electrophysiological tests were relatively frequent in the patient group. No correlation was found between abnormalities in one test compared to abnormalities in the other tests. Furthermore, no correlation was found between the number of electrophysiological abnormalities and the frequency of the disease in the nearest family. The number of abnormal electrophysiological tests increased, however, with age of the patients and duration of the disease.
The P2 latency of the pattern reversal visual evoked response was measured in 11 patients with hereditary motor and sensory neuropathy (HMSN). The P2 latency was inversely related to the peripheral nerve conduction velocity, but no significant relation was found between the P2 latency and the age of the patients or the duration of their symptoms. When the whole group was considered the mean P2 latency was longer but not significantly different from a control group. When the 11 patients were differentiated into HMSN I (5 males) and HMSN II (2 females, 4 males) the P2 latencies of the patients with HMSN I were significantly longer than those with HMSN II. The data support earlier findings that subclinical involvement of the optic nerve may occur in HMSN and suggest that measurement of P2 latency may be of value in the differentiation of HMSN. More than two subtypes, however, may exist.
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Forty five insulin dependent diabetics were randomised to treatment with continuous subcutaneous insulin infusion (CSII), multiple insulin injections (five or six daily), or conventional twice daily insulin injections. Near normoglycaemia was obtained with CSII and multiple injections but not with conventional treatment (p less than 0.01). Hypoglycaemic coma was observed less frequently with CSII than with multiple injections and conventional treatment (p less than 0.001), but blood glucose concentrations below 2.5 mmol/l (45 mg/100 ml) were more common. After two years fewer retinal microaneurysms and haemorrhages had developed in the patients given CSII and multiple injections compared with those given conventional treatment, in whom the number had increased significantly (p less than 0.01). Motor nerve conduction velocity deteriorated in the patients given conventional treatment; in those given CSII it was unchanged during the first year but had improved after two years (p less than 0.01). Glomerular hyperfiltration was reduced with CSII, but no change occurred in urine albumin excretion rates. Long term near normoglycaemia may prevent the progression of early stages of late diabetic complications.
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.
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.
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.
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.
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.
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.
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