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Biomedical subjects

C Geyer

Publications and source records attributed to C Geyer.

29 records · Page 2Linked to original sources
PubMed1991

[Metastasizing glioma in a Boxer].

A metastasizing glioma in a 4-year-old boxer bitch is described. Clinical symptoms included ataxia, blindness, and increased cervical pain sensation. The tumor metastasized to an extraordinary extent via the cerebrospinal fluid. Tumor masses surrounded the whole spinal cord including the cauda equina. Histological examination revealed a variable morphology of the glioma. Immunohistochemical investigations showed some tumor cells reacting with antibodies specific to GFAP and S-100 protein. In contrast, NSE, 200 kd NF, vimentin, and desmin could not be demonstrated within tumor cells. The results are discussed in detail.

Animals↗
PubMed1987

[Alpha 2 -interferon therapy in metastasizing malignant melanoma].

Low doses of recombinant alpha 2-interferon were administered to 20 patients with stage III malignant melanoma. Dosage was 2.5 million IU intramuscularly daily in the first four weeks, then 2.5 million IU twice a week. The treatment was well tolerated, but there was no definitely demonstrable therapeutic effect. Only two patients are still alive (average survival time of the patients who died was 24 +/- 15 weeks). When there were distant organ metastases at the onset of treatment, survival time was 16 +/- 8 weeks, in case of distant skin metastases 37 +/- 16 weeks. Comparison of this group with a previously treated "control" group indicated that patients treated with interferon have a shorter survival time. However, all of them were far advanced cases with already shortened life expectancy, so that any comparison with the control group is limited.

Adult↗
PubMed1986

[Pigmented actinic keratoses].

Four cases of pigmented solar keratoses are reported. The brownish pigmented lesions on sun-exposed skin are clinically similar to lentigo simplex, lentigo senilis, lentigo maligna and pigmented seborrhoic keratosis. The surface is rather rough. Histologically, in addition to characteristic findings of solar keratoses, melanin can be found within the lower epidermis and within melanophages in the upper dermis (incontinence of pigment).

Aged↗
PubMed1985

[Microscopic study of the corneal epithelium based on intracellular turnover of fluorogenic substrates].

The methods presently available for examination of the corneal epithelium by use of the ophthalmic slit lamp are more or less restricted to the detection and diagnosis of significant lesions and the morphological results of pathologic processes in the epithelial layer at relatively low magnification and optical resolution. There is an increasing demand, however, for early detection of initial damaging effects to the corneal epithelium by testing simple specific reactions at cell level. Fluorescein microscopy of the intracellular turnover of fluorogenic substrates may become a valuable methodological basis for such an examination of the corneal epithelium. Orienting experimental investigations into the uptake and turnover of fluorescein-di-acetate (FDA) by the epithelial cells of the rabbit cornea after its exposure to isotonic 10(-5) molar FDA solution, using an endothelial specular microscope and an image intensifier TV camera, demonstrate that this principle permits a superior microscopic presentation not only of the cellular epithelial structure in general, but also of locally damaged areas of the epithelium immediately after their exposure to damaging chemical agents, in particular to substances affecting cell membranes.

Animals↗
PubMed1983

Aminergic blockade modulates long-term potentiation in the dentate gyrus of freely moving rats.

Long-term potentiation (LTP) was induced in the dentate gyrus of freely moving rats by tetanic stimulation of the medial entorhinal cortex under conditions of catecholamine depletion by 200 mg/kg alpha-Methyl-para-tyrosine (AMPT) or blockade of alleged dopamine receptors by 0.5 mg/kg haloperidol. Both substances did not change significantly the normal excitability of the glutamatergic perforant pathway, but affected the establishment of LTP. Whereas the potentiation effect on the EPSP component of the monosynaptic field potential was not changed by both substances when compared to the potentiation of controls, the potentiation of the population spike was prolonged and enhanced. These results point to an effect of catecholaminergic blockade on postsynaptic membranes of the target cells or on other components of the neuronal network but not to a specific influence on the homosynaptic mechanisms of LTP.

Animals↗
PubMedDate not supplied

Somatosensory evoked potentials and magnetic resonance imaging in intraspinal neoplasms.

Median and posterior tibial somatosensory evoked potentials (SEPs) were studied on 25 patients with pathologically proven intraspinal neoplasms, and the results were compared and correlated with the details of clinical examination and the information derived from magnetic resonance imaging (MR). MR was abnormal in all cases and in 23 of 25 (92%) demonstrated an intraspinal expansile lesion. SEP was abnormal in 19 of 25 patients (76%). Abnormal SEPs were found in 18 of 19 patients (94%) with cervical or thoracic neoplasms but only in 1 of 6 patients (16%) with the tumor in the thoracolumbar or lumbar region. SEP-MR correlation was significant (P less than 0.05) for thoracic intraspinal neoplasms where all 9 had an abnormal SEP showing a similar pattern of normal median and abnormal posterior tibial study. Clinically, all 7 patients with posterior column sensory deficits had abnormal SEP (100%). Abnormal SEPs were seen in 7 of 11 (63%) patients with spinothalamic deficits and in 4 of 8 (50%) of those with normal sensory examinations. Four of 9 patients (44%) with a normal neurological examination or an examination disclosing ambiguous results indistinguishable from a peripheral pathology had an abnormal SEP strongly suggesting a central sensory disorder. Comparison of preoperative and postoperative SEPs did not disclose useful prognostic information pertaining to the functional recovery.

Adolescent↗
PubMedDate not supplied

Somatosensory evoked potentials and magnetic resonance imaging in syringomyelia.

Somatosensory evoked potentials (SEPs) to median and posterior tibial stimulation were obtained in 22 patients with syringomyelia. All patients had magnetic resonance imaging (MR) which defined the maximum transverse diameter of the syrinx as well as its longitudinal extension. SEP was abnormal in 16 (72%) patients. Median and posterior tibial SEPs were abnormal in 11 and 15 patients respectively. Both tests were abnormal in 10 patients. Ten patients showed absence of one or more central potentials (P/N13, N20, N22) and 7 patients demonstrated increased conduction times (N9-N20, P/N13-N20, N22-P40). The mean maximum transverse diameter of the syrinx was 7.5 mm in patients with normal SEPs and 16.2 mm in patients with abnormal SEPs. Abnormal SEP was observed in all 5 patients with loss of position sense, in 9 of 13 (69%) with loss of superficial pain and temperature, and 1 of 2 patients with motor deficit only. Central SEP abnormalities were observed in 3 of 5 patients with sensory deficits indistinguishable from a peripheral neuropathy and in 2 patients in the asymptomatic extremity. Three of 4 patients with syringomyelia and Chiari malformation had a normal SEP.

Adolescent↗
PubMedDate not supplied

[Adaptation osteotomy in idiopathic femoral head necrosis].

Thirty-nine patients who suffered a segmental ischemic necrosis of the hip, fifteen of which affected on both sides, were treated with osteotomy of the femur. The re-examinations were carried out after an average period of 6.6 (2.5-12) years. While in twenty one cases, the hip necrosis was treated exclusively by varisation, in thirty three cases a combination of varisation and flexion was effected. 12 patients (equivalent to 22.2%), all of them with a necrotic angle of more than 115 degrees, were provided with a total hip arthroplasty in the interval. The patients with a necrotic angle smaller than 115 degrees showed a definite alleviation of the pain symptoms, an increased hip flexibility and an improved locomotory pattern.

Adult↗
PubMedDate not supplied

Tegmental defects and cerebrospinal fluid otorrhea.

Congenital tegmental defects that present as unsuspected cerebrospinal fluid (CSF) otorrhea are diagnostic and therapeutic challenges. We reviewed 5 such patients to determine an optimal strategy for evaluation. Five patients presented with watery otorrhea, 4 of them after ventilation tube placement, and only 1 with rhinorrhea. The preoperative analysis of middle ear effusion for beta(2)-transferrin was positive in 2/4, equivocal in 1/4 and false negative in 1/4. Computerized tomography (CT) revealed nonspecific tegmental defects in all 5 patients. Magnetic resonance imaging (MRI) demonstrated meningoencephalocele in 3/5 and dural irregularity in 1/5. Tegmental defects were confirmed at surgery in all cases, demonstrating meningocele or arachnoid granulations in 2/5 and encephalocele in 2/5 patients. We recommend a combination of beta(2)-transferrin analysis to verify CSF, high resolution CT (axial and coronal planes) to diagnose tegmental defects, and MRI (multiplanar) to evaluate the type of herniation. A combination mastoid and middle fossa approach for definitive repair is suggested.

Aged↗