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Biomedical subjects

S Wenger

Publications and source records attributed to S Wenger.

28 records · Page 2Linked to original sources
PubMed1994

Initiation of visual-guided random saccades and remembered saccades in parkinsonian patients with severe motor-fluctuations.

We studied the initiation of saccades to visual-guided random time and remembered targets in a group of nine Parkinsonian patients with severe motor fluctuations and in 9 age matched control subjects. In contrast to a marked skeletomotor improvement during the "on" condition, saccadic latencies for both visual-guided random saccades and remembered saccades were increased in the patients during the "on" condition compared to the "off" condition. This result of dissociation between skeletomotor and oculomotor function indicates that common concepts of saccadic initiation in parkinsonian patients do not hold true in patients with severe fluctuations since dopaminergic stimulation seems to increase saccadic latencies in these patients.

Aged↗
PubMed1994

[Intraoperative irrigation of the subdural space after traumatic spinal cord lesions (based on 4 case examples)].

In experimental investigations on primates it has been shown that after a standardized transverse lesion of the spinal cord subdural perfusion with an artificial liquor solution (Elliot's B solution) of the region of the injury improved the eventual motoric function achieved. We tried to reproduce these experimental results in the management of four patients with acute spinal cord injury after trauma of the vertebral column. Due to the difficulty of an exact evaluation in this initial study an objective positive effect of perfusion with Ringer solution (at 37 degrees C) could not be confirmed in these patients. Nevertheless, the possibility of a positive influence of this adjuvant operative treatment on spinal cord injuries should be studied in a greater collective of patients. A multicentre study would be essential because of the limited number of cases in a single hospital.

Adult↗
PubMed1993

Dopamine D2 receptor imaging and measurement with SPECT.

Only recently it has become possible to label and visualize dopamine D2 receptors in the living human brain using an [123I]labeled ligand and the SPECT technique. Iodobenzamide (S(-)IBZM) is a substance with high affinity and high specificity for D2 receptors and was used in controls and in patients with different extrapyramidal disorders. After the i.v. administration of 5mCi (185 MBq) of [123I] labeled S(-)IBZM data collection was performed with a rotating double head scintillation camera between 60 and 110 minutes. In a semiquantitative approach a ratio was calculated between mean counts/pixel in the striatum and a region in the lateral frontal cortex, which gives an index of receptor density. In a group of 21 controls this ratio is 1.73 +/- 0.09. A highly significant age-related decline is found in controls and in 57 patients with PD. PD patients without L-DOPA or dopamine agonist treatment do not differ from controls (1.72 +/- 0.09; n = 18), whereas patients under dopaminergic therapy show a significantly lower binding ratio (1.65 +/- 0.13; n = 39; p = 0.017) suggesting receptor downregulation. Comparing the striatum ipsi- and contralateral to clinical symptoms in 18 hemiparkinsonian patients shows slightly but significantly higher values on the contralateral side, indicating receptor supersensitivity (1.71 +/- 0.11 vs. 1.66 +/- 0.09; p = 0.0014). No correlation between D2 receptor binding and clinical stage, duration of disease or duration of dopaminergic therapy exists. Markedly reduced ratios are measured in 7 patients with progressive supranuclear palsy and multiple system atrophies and in 18 patients with Huntington's disease (1.40 +/- 0.09 and 1.37 +/- 0.12 respectively; p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Dopamine D2 receptor imaging with SPECT: studies in different neuropsychiatric disorders.

The purpose of the present study is to visualize and quantify dopamine D2 receptors in the living human brain using an 123I-labeled ligand and the single photon emission computerized tomography (SPECT) technique. S-(-)-Iodobenzamide [S-(-)-IBZM] has been shown to be a highly selective ligand with high affinity for D2 receptors in experimental studies. Five millicuries (185 MBq) of 123I-labeled S-(-)-IBZM was administered intravenously to 12 control subjects, 22 parkinsonian patients under L-Dopa therapy, 12 parkinsonian patients without L-Dopa, 10 unmedicated patients with Huntington's disease, and 12 patients under different neuroleptics. Data collection with a rotating double-head scintillation camera started 1 h after injection and lasted for 50 min. In a semiquantitative approach, a ratio was calculated between mean counts per pixel in the striatum and a region in the lateral frontal cortex, which was 1.74 +/- 0.10 in the control group. A marked reduction of this ratio was found in patients with Huntington's disease (1.38 +/- 0.12; p = 0.0001), no significant changes in untreated parkinsonian patients (1.67 +/- 0.14), but a reduction in L-Dopa-treated cases (1.59 +/- 0.13; p = 0.0014). A curvilinear relationship was found between total daily dose of neuroleptics and the reduction of this ratio. Estimated receptor blockade under full neuroleptic treatment was 75-80%. S-(-)-IBZM binding was reduced with increasing age (p less than 0.01). Specific binding was reduced markedly when the racemic mixture of IBZM was used, and no specific binding was seen with the R-(+)-isomer, demonstrating the stereoselectivity of IBZM binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Dopamine receptor classification, neuroanatomical distribution and in vivo imaging.

The classification of dopamine receptors and their neuroanatomical distribution is reviewed, including the newly discovered D3, D4 and D5 subtypes. In vivo imaging techniques and methods for quantification are briefly described and PET and SPECT studies of D2 receptors in schizophrenia, under neuroleptic treatment, in aging, Parkinson's disease, Huntington's disease, tardive dyskinesia and multisystem atrophies are reviewed and compared with our own results. A short description is given of imaging studies of D1 receptors.

Brain↗
PubMed1987

Lack of mitogenic effects of growth hormone on human leukemic lymphoblasts.

To determine whether human growth hormone (HGH) can cause proliferation of human leukemic lymphoblasts, we studied colony formation in semi-solid medium of MOLT 4, a cell line derived from an adolescent with acute lymphoblastic leukemia (ALL). Although exposure to single doses of HGH in supraphysiologic concentrations resulted in almost two-fold increases in number of colonies compared with control samples, physiologic concentrations had no effect. Similarly, physiologic concentrations of HGH had no effect on thymidine incorporation in short-term cultures of fresh lymphoblasts from children with ALL. In addition, total white blood cell and differential counts in 14 children with isolated growth hormone deficiency were reviewed pre- and post-treatment with HGH. In no case was there evidence of in vivo lymphocytosis or blastogenesis.

Cell Line↗
PubMedDate not supplied

SPECT and MR imaging in herpes simplex encephalitis.

Two cases of necrotizing herpes simplex encephalitis (HSE) were investigated with 99mTc-hexamethylpropyleneamineoxime (HMPAO) SPECT and MR. The clinical course was compared with the neuroimaging results. In the acute stage, the increased HMPAO uptake matched the MR hyperintense signal in the limbic temporal lobe and in the basal ganglia. Protracted inflammation was accompanied by persistently high HMPAO uptake. The sequelae of HSE were characterized by decreased HMPAO uptake and postnecrotic widening of the temporal horns. The "limbic" pattern recognized in both SPECT and MR reflects the basic pathophysiology and neuropathology of HSE. Both methods may be useful in the diagnosis and follow-up of HSE.

Contrast Media↗