Antibodies to sulfatide in leprosy and leprosy reactions.

Antibodies to sulfatide have been reported in various demyelinating peripheral polyneuropathies. We have investigated the diagnostic value of these antibodies in leprosy. Anti-sulfatide IgM in leprosy patients was not significantly elevated. High anti-sulfatide IgG titers were observed in individuals from endemic areas, irrespective of their leprosy status, while western European controls were negative. No significant correlation was found between IgM or IgG antibody titers and leprosy classification, although multibacillary patients had higher anti-sulfatide IgM titers than paucibacillary patients. In addition, 23 patients developing leprosy reactions were followed longitudinally. Antibody titers in these patients fluctuated slightly during the follow-up period. There was no association with the occurrence of leprosy reactions or treatment. Thus, IgG titers against sulfatides are high in both leprosy patients and healthy controls in endemic areas, whereas such antibodies are not found in western European controls, suggesting that these antibodies are induced by environmental factors, such as microorganisms.

Natural history of ultrasound hip abnormalities in clinically normal newborns.

One hundred one clinically normal newborn hips showed varying degrees of sonographic hip dysplasia according to the classification of Graf. None were treated, and after +/- 6 months, radiographs showed that only four had definite dysplasia. Of these, three had had risk factors such as breech delivery or familial predisposition. Forty-three other clinically normal newborn hips showed ultrasonic instability, which spontaneously corrected. The severity of ultrasound dysplasia at birth was not related to ultimate development of the hip. Our results indicate that ultrasound should not be performed as a general screening procedure in clinically normal newborns.

[Videodensitometry in echoencephalography of premature infants]. / Videodensitometrie bei der Echoenzephalographie von Frühgeborenen.

In 22 premature children (12 normal prematures and 10 with brain pathology) echodensity was measured as average grey scale values. For performing the measurements, echoencephalograms were recorded on videotape and analysed by an IBM-AT computer and a high resolution framegrabber. An evident difference of echodensity was measured between normal parenchyma, skull, fresh cerebral haemorrhages and cerebral oedema.

Continuous intravenous ammonia infusion as a model for the study of hepatic encephalopathy in rabbits.

To obtain a more precise pathophysiological evaluation of the role of ammonia in acute hepatic encephalopathy, we compared the plasma ammonia concentrations and electroencephalographic recordings (EEGs) of rabbits with surgically induced acute hepatic failure (AHF, n = 10) and normal rabbits administered an infusion of ammonium acetate (NH4-Ac, n = 7) over a 10-hr period. AHF was surgically induced by portocaval shunting followed by hepatic artery ligation 48 hr later. In the infusion group the dose of NH4-Ac, initially 0.78 mmol/kg/hr, was increased every 2 hr by 0.13 mmole/kg/hr during a 10-hour period to simulate the arterial NH3 concentrations observed in AHF. Ammonia levels in rabbits administered the NH4-Ac infusion were identical to those observed in AHF, with the exception of the higher initial value in the AHF group. Moreover, the mean rates of increase in grade of encephalopathy in the two groups were similar, although the EEG grades in the infusion group were significantly less at all time points. In conclusion, this study demonstrates that a more pathophysiological approach to identification of the putative toxins in hepatic encephalopathy is feasible. Some of the EEG abnormalities of acute hepatic encephalopathy in rabbits are presumably due to hyperammonemia; the encephalopathy observed in AHF at zero time is probably caused by the previously constructed portocaval shunt via an undefined, but possibly also ammonia-related, mechanism.

Diagnostic ultrasound equipment. Safety and dosimetry.

A survey of present opinions on the safety of diagnostic ultrasound applications is presented together with some data on output levels. Physical mechanisms involved in potential adverse effects are described. Labelling requirements of the equipment are defined and specified. These requirements are contained in a recent proposal of the Netherlands' Committee on the Safety of Ultrasound.

A surgical model of fulminant hepatic failure in the rabbit: different effects of end-to-side versus small-diameter side-to-side portacaval shunt.

We developed a rabbit model of fulminant hepatic failure by way of a two-staged total liver devascularisation procedure. For the first-stage procedure (portosystemic shunting), the clinical, biochemical and electro-encephalographic courses in 6 rabbits (group I) with an end-to-side portacaval shunt (ETS-PCS), 6 rabbits (group II) with a small-diameter side-to-side portacaval shunt (STS-PCS) and 6 rabbits (group III) with the same STS-PCS and 48 h of pretreatment with oxytetracycline were investigated and compared to 6 sham rabbits (group IV). The limited survival, the fall in clotting factors and the rapid development of hyperammonaemia with encephalopathy within 48 h in group I point to ETS-PCS-associated ischaemic liver necrosis. Group II showed improved survival, but was associated with portosystemic encephalopathy. Rabbits in group III survived portosystemic surgery without development of marked encephalopathy. In all animals of group III, the second-stage procedure (tightening of the loose ligature around the afferent hepatic vessels) could be performed, and a suitable model of fulminant hepatic failure was obtained.

Real-time compound scanning for echoencephalography.

A new ultrasonic scanning method is introduced for examination of the infant brain as for instance in cases of intracerebral haemorrhages or hydrocephalus. The examinations are carried out with an electronic phased array compound scanner with dynamic focussing. Tomograms of the cranium are obtained in three dimensions. With dynamic focussing arbitrarily chosen brain structures can be shown in more detail. The examinations can be carried out at the bed-side or even in an incubator.

Objective measurement of hepatic encephalopathy in pigs by means of spectral analysis and evoked responses.

Objective measurement of hepatic encephalopathy by means of spectral analysis of the electroencephalogram (EEG), visual-evoked potentials (VEP) and brainstem auditory-evoked potentials (BAEP) was studied in pigs with ischemic hepatic necrosis. The mean dominant frequency (MDF) and the relative power of the delta frequency band (% delta power) showed significant changes with increasing encephalographic grades of encephalopathy: MDF dropped from 7.0 +/- 0.5 (grade 0) to 2.7 +/- 0.3 Hz (grade 3 encephalopathy) and % delta power increased from 52 +/- 7 (grade 0) to 83 +/- 6% (grade 3). The patterns of the VEP in pigs corresponded to those of the human VEP. However, significant differences in either latency time of the peaks or the peak amplitude with increasing stages of hepatic encephalopathy could not be found. The BAEP registered for pigs were reproducible but also were not as useful as spectral analysis for grading hepatic encephalopathy.

Tolerance to nitrous oxide in volunteers.

Nociception and loss of awareness during exposure to anaesthetic concentration of nitrous oxide (N2O) were studied in eight male medical students. The cold water nociception test, where a hand is immersed in 0 degree C stirred water, was used for measurement of nociception. At irregular intervals an auditory command was given to oppose two fingers, and this served to monitor consciousness. The selected inspiratory concentration of N2O used per individual was sufficient to induce a loss of consciousness for more than 2.5 min, within 10 min of exposure to N2O. This concentration of N2O varied from 60% to 80%. The experimental exposure to N2O lasted 3 h. In all volunteers significant antinociception was observed within 2 min of exposure to N2O. The maximal analgesic effect was observed between 20 and 30 min of exposure to N2O. The analgesic effect of N2O gradually decreased and was absent in all eight volunteers within 150 min. Two volunteers regained consciousness at 77 and 91 min of exposure, whilst still breathing 60 and 80% N2O. These results show that tolerance to antinociceptive effects of N2O in man rapidly develops and that awareness may occur in some volunteers during prolonged exposure to N2O.

Absence of electroencephalographic excitation pattern under isoflurane anesthesia.

In twelve patients the EEG was recorded under isoflurane--nitrous oxide inhalation anesthesia. A quiet EEG pattern was registered, without suppressions and seizures of spike activity which are often observed under enflurane. This was the case even when end expiratory CO2 shifted to low values (3-3.6 Vol%). In one patient the induction with N2O/O2 and thiopentone, resulted in spikes and suppression bursts on the EEG. After isoflurane was added, these changes disappeared. In another patient, epileptic EEG patterns were observed prior to the induction (confirmed by the history of the patient). During isoflurane anesthesia the epileptic waves disappeared and remained absent.

Objective measurement of hepatic encephalopathy by means of automated EEG analysis.

Automated analysis of the electroencephalogram as an objective measurement of hepatic encephalopathy for the individual patient was investigated. The mean dominant frequency of patients with grades 0 and 1 hepatic encephalopathy was in the normal range (greater than or equal to 6.4 Hz); grade 1 hepatic encephalopathy, however, was characterized by abnormal relative power of theta activity of more than 35%. Twelve out of 34 patients with clinical grade 0 hepatic encephalopathy also had an elevated power of theta activity and probably therefore latent hepatic encephalopathy. Patients with grades 2, 3 and 4 hepatic encephalopathy had a low mean dominant frequency (less than 6.4 Hz) and could be identified by a biphasic power spectrum (theta and delta peaks, grade 2) or by a high power of delta activity (greater than or equal to 70%, grade 3-4). We conclude that automated EEG analysis based on the parameters mean dominant frequency and the relative powers of the delta and theta band is very suitable for objective classification of hepatic encephalopathy in individual patients.

Visual evoked potentials, auditory evoked potentials and EEG in shunted hydrocephalic children.

Visual evoked potentials (VEP) and auditory evoked potentials (AEP) were studied together with the EEG, in 15 hydrocephalic children who had been shunted previously, and in a control group of 10 normal children. From the control group normal VEP's, AEP's and EEG's were obtained. In all 15 hydrocephalic children the EEG was abnormal. AEP's were normal in 9 and abnormal in 6 cases. VEP's were normal in 7 and abnormal in 8 cases. Only 4 patients showed both abnormal VEP's and AEP's. No relation could be demonstrated between the severity of EEG disturbances and evoked response abnormalities.

Evaluation of echoencephalography.

Clinical use of A- and B-mode echoencephalography in neurology, neurosurgery, and pediatrics is discussed, and some results are presented. Descriptions are given of several techniques to obtain two-dimensional echoencephalographic pictures. Two-dimensional echoencephalography can be particularly helpful with hydrocephalic babies. Recording techniques for pulsatile echoencephalography and the factors influencing the shape of cerebral echo pulsations are considered. Also, the diagnostic value of pulsatile echoencephalography in several brain diseases is discussed.

Bromine in blood, EEG and transaminases in methyl bromide workers.

In 33 methyl bromide users, slight electroencephalographic changes (in 10 subjects) and a small increase in serum transaminases were found which could be related to bromine concentration in blood. No relationship was found with subjective symptoms, general neurological examination or the results of serum protein electrophoresis.

Infantile spasms associated with hemihypsarrhythmia and hemimegalencephaly.

A case of unilateral megalencephaly in a four-week-old child with infantile spasms and hemihypsarrhythmia is presented. The histological and histometrical investigations showed signs of immaturity in the cortex of the megalencephalic hemisphere.

Hemoglobin A2 levels in malaria patients.

The influence of malaria on the hemoglobin A2 (Hb A2) level in humans was studied in a series of 94 imported cases in Belgium. Sixty-nine of the patients were natives of Western European countries, their results are reported separately since their origin and the results of their hematological examination made it unlikely that they carried the beta-thalassemia trait. The Hb A2 level of the 94 malaria patients (mean 2.76%; S.D. 0.51%) was not statistically different from that found in 60 healthy controls (mean 2.70%; S.D. 0.38%; P greater than 40). Likewise the level of the 65 Western European patients was not statistically different from that of the same controls (mean 2.81%; S.D. 0.42%; P greater than 0.10). There was also no significant difference between the level in patients infected with a particular species of Plasmodium and that of the controls. No correlation was found between the Hb A2 level and the intensity of the parasitemia or the concentration of total hemoglobin in the blood. These results are discussed in comparison with the divergent ones obtained by others and it is suggested that malaria has no significant influence on the results of surveys for the prevalence of beta-thalassemia in regions of malaria endemicity.

A directional quantifying Doppler system for measurement of transport velocity of blood.

A transcutaneous Doppler device has been developed that measures primarily the directional transport velocity of blood, averaged over the vessel diameter, irrespective of its flow in adjacent vessels. Directional information is obtained by high or low-pass filtering of frequency converted versions of the received Doppler signals, applying low-cost, sharp filters in a superheterodyne system. Upper and lower channel signals are quantified separately to average directional velocity. Linear results from in vitro measurements are obtained.