Biomedical subjects

D Sontheimer

Publications and source records attributed to D Sontheimer.

5 recordsLinked to original sources

PubMed1991

High-dose intravenous gammaglobulin for neonatal alloimmune thrombocytopenia in twins.

We report the successful treatment of neonatal alloimmune thrombocytopenia with repeated infusions of high-dose immunoglobulin G (400 mg/kg/d for 5 days) in twins. Platelet counts increased within 3 days from less than 20 x 10(9)/l to more than 70 x 10(9)/l. The first twin survived without neurological or other sequelae. The second twin had probably developed intracranial hemorrhage (ICH) in utero. This infant developed long-term neurological sequelae with blindness, cerebral palsy and infantile spasms. Implications of the therapeutic approach and prevention of severe complications in pregnancies with known risk for neonatal alloimmune thrombocytopenia are discussed.

Autoimmune Diseases↗

PubMed1990

EEG development in early treated PKU patients from birth to 6 years of age.

In 126 early treated PKU patients (type I and type II) a close EEG follow up was performed from birth up to 6 years of age. A total of 1465 EEGs were performed before and after onset of dietary treatment and on 11 more subsequent occasions. The composition of the background activity was normal up to 6 years when only a small number of the children (19) showed no dominant alpha activity. The frequency of epileptiform activity of generalised as well as focal type was low in the first 2 years of life, but afterwards slightly enhanced in comparison to normal control groups. Other findings like generalised theta paroxysms or focal slow waves were rarely observed. Under a standardised protein load at 6 months (52 patients) and at 5 years of age (42 patients) a moderate generalised slowing of the background activity but no other abnormalities were noted.

Aging↗

PubMed1989

Visual information processing in infancy.

The author examined the construct validity of visual information processing in infancy (preference for novel visual targets) as a predictor of later neurological outcome. 104 infants with definite (N = 25), questionable (N = 27) or no evidence of neurological dysfunction (N = 52) were tested at three to seven months (corrected age). The mean novelty preference scores differed significantly between the three groups. These differences were not related to demographic data and still existed when the data were corrected for preterm birth and birthweight. These results support the hypothesis that visual information processing at three to seven months (corrected age) is a reflection of neurological intactness and may be useful in the clinical assessment of cortical function in infants.

Central Nervous System Diseases↗

PubMed1985

Intra- and extracranially recorded auditory evoked potentials in the cat. II. Effects of interaural time and intensity differences.

The effects of interaural time differences and interaural intensity differences on binaural interactions in the brain-stem evoked response (BSER) and auditory field potentials (AFPs) in superior olive and inferior colliculus were studied. Interaural time differences of up to +/- 2048 microseconds and interaural intensity differences of up to +/- 30 dB were used. Binaural interactions were studied for waves P4 and P5 of the BSER and the corresponding AFP components. When binaural interactions were present (wave P4 and subsequent waves), the dichotic potential was less than the sum of left and right evoked potentials. At zero interaural intensity difference the maximum binaural interaction was seen at zero interaural time difference. When an interaural intensity difference was present, maximum interaction was shifted away from zero interaural time difference such that left louder gave maximal interaction at right lead and vice versa. The time intensity trading values for this shift were between 9 and 20 microseconds/dB. The trading ratios for the superior olive wave P4 component and BSER P4/P5 were in the same range, i.e., no extra effects could be seen in the BSER postsynaptic to the superior olive. These time intensity trading ratios correspond to those of medial superior olive cells but not to those of lateral superior olive cells (Caird and Klinke 1983). We suggest that these binaural effects are produced by binaural mechanisms in the medial superior olive and that the lateral superior olive does not significantly contribute to the BSER. The inferior colliculus AFP slow wave binaural interactions do not correspond to those of the BSER.

Acoustic Stimulation↗

PubMed1985

Intra- and extracranially recorded auditory evoked potentials in the cat. I. Source location and binaural interaction.

Auditory field potentials (AFPs) were recorded stereotactically from the superior olivary complex and from the exposed inferior colliculus in the Nembutal anaesthetized cat. The brain-stem evoked response (BSER) was recorded simultaneously between an electrode on the dura mater at the vertex and an electrode on one bulla or in the neck musculature. A closed condenser microphone sound system was used to deliver monaural and binaural clicks. The binaural difference potential (BDP) was calculated by subtracting the sum of both monaurally evoked potentials from the binaurally evoked potential. The first binaural interaction was a reduction of BSER wave P4, arising in the superior olivary complex. The large extracellular AFPs generated in both inferior colliculus and superior olivary complex do not correspond to BSER waves, whereas the small volleys preceding the main waves do. These small waves show a much smaller change with recording distance than do the main AFP waves, i.e., the sources and sinks generating these waves appear to be more widely separated. We suggest that, in contrast to extracellular field potentials, the BSER is generated by action potentials in fibre tracts rather than postsynaptic potentials in nuclei. The implications for stimulation and recording laterality of late BSER waves are discussed.

Animals↗