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Biomedical subjects

R Kleinert

Publications and source records attributed to R Kleinert.

At least 73 records · Page 4Linked to original sources
PubMed1990

Peculiar changes in Rosenthal fibres in an atypical astrocytoma.

A 50-year-old female patient died of an untreatable glioma apoplecticum. At autopsy a strongly vascularized glial tumour was found. The criteria for malignancy according to the WHO classification were only partially fulfilled by this tumour which displayed morphological features of an astrocytoma but could not be further subclassified. By light microscopy, angioma-like vascular proliferations, large cells with brightly eosinophilic cytoplasm, and small cells with hyperchromatic nuclei were found. Most large cells had vesicular, excentrically placed nuclei and contained fibrillary whorls or amorphous, irregular cytoplasmic inclusions. By immunohistochemical staining, using antibodies to glial fibrillary acidic protein (GFAP) the fibrillary whorls were identified as aggregates of glial filaments. The amorphous inclusions lacked GFAP immunoreactivity and appeared in the electron microscope as electron dense material surrounded by a dense network of glial filaments. The abnormal perikaryal inclusions of these atypical astrocytoma cells appeared to be peculiar alterations of Rosenthal fibres closely mimicing Mallory bodies.

Astrocytes↗
PubMed1990

Obstructive jaundice: use of expandable metal endoprosthesis for biliary drainage. Work in progress.

Expandable metal endoprostheses were implanted transhepatically in 61 patients with obstructive jaundice. Fifty-three patients had malignant and eight had benign obstructions. Because of the small diameter of the compressed stent (7 F), primary implantation of the stent without a previous catheter drainage was preferred. Postprocedural complications occurred in three patients (5%) (biliary pleuritis, peritonitis, hepatic artery aneurysm). The 30-day mortality rate was 8.2%. Reocclusions were observed in six of the patients with malignant obstructions (11%) (observation period, 1-10 months; mean, 4.5 months) and in two of the patients with benign stenoses (25%) (observation period, 3-21 months; mean, 9 months). The higher reocclusion rate of benign obstructions must be interpreted with care because of the small number of patients. From their preliminary experience, the authors conclude that expandable metal endoprostheses offer patency rates equal to those of plastic stents. The implantation trauma is reduced due to the small 7-F introducing catheter system.

Bile Ducts↗
PubMed1990

Brain neurotransmitter changes in three patients who had a fatal hyperthermia syndrome.

The authors examined the autopsied brains from three patients who had a fatal hyperthermia syndrome. There was marked hypothalamic noradrenaline depletion in all three patients, severe brain choline acetyltransferase deficiency with nucleus basalis cell loss in two patients, and mild to moderate brain choline acetyltransferase loss in one patient. Striatal dopamine metabolite/dopamine ratio was below normal in two patients and not elevated, as would be expected after short-term neuroleptic administration, in the third. This suggests that reduced capability (aggravated by the cholinergic deficit) of the nigrostriatal dopamine system to respond adequately to stress and/or neuroleptic-induced receptor blockade may be important in the development and course of fatal hyperthermia syndrome.

Adolescent↗
PubMed1989

Contact probes for intravascular laser recanalization. Experimental evaluation.

Experimental laser ablation of atheromatous plaques was performed with a bare quartz glass fiber, a metal probe, and a sapphire probe. The tissue response after irradiation with increasing energies was evaluated by means of light and scanning electron microscopy. Laser emission through the bare fiber caused a narrow, deep crater with an irregular surface surrounded by a zone of thermal necrosis. After tissue ablation with the metal probe, a disproportion between the small tissue defect and the large zone of thermal necrosis was observed. The largest tissue defect was vaporized by the sapphire contact probe. A small zone of thermal necrosis surrounded the laser crater.

Arteries↗
PubMed1989

MR findings in methotrexate-induced CNS abnormalities.

MR of the brain was performed in eight patients (mean age, 14.9 years) with osteogenic sarcoma during or after IV treatment with high-dose methotrexate. MR detected brain abnormalities in four patients, three of whom had concomitant neurologic dysfunction. Pathologic findings demonstrated on MR were (1) chronic brain edema, demonstrable over a period of 3-14 months (proved by autopsy in one patient); (2) multifocal white matter necrosis; and (3) deep brain atrophy. MR appears to be valuable in the detection of abnormalities induced by treatment with high-dose methotrexate.

Adolescent↗
PubMed1989

Endoscopic surgery versus medical treatment for spontaneous intracerebral hematoma: a randomized study.

A controlled randomized study of endoscopic evacuation versus medical treatment was performed in 100 patients with spontaneous supratentorial intracerebral (subcortical, putaminal, and thalamic) hematomas. Patients with aneurysms, arteriovenous malformations, brain tumors, or head injuries were excluded. Criteria for inclusion were as follows: patients' age between 30 and 80 years; a hematoma volume of more than 10 cu cm; the presence of neurological or consciousness impairment; the appropriateness of surgery from a medical and anesthesiological point of view; and the initiation of treatment within 48 hours after hemorrhage. The criteria of randomization were the location, size, and side of the hematoma as well as the patient's age, state of consciousness, and history of hypertension. Evaluation of outcome was performed 6 months after hemorrhage. Surgical patients with subcortical hematomas showed a significantly lower mortality rate (30%) than their medically treated counterparts (70%, p less than 0.05). Moreover, 40% of these patients had a good outcome with no or only a minimal deficit versus 25% in the medically treated group; the difference was statistically significant for operated patients with no postoperative deficit (p less than 0.01). Surgical patients with hematomas smaller than 50 cu cm made a significantly better functional recovery than did patients of the medically treated group, but had a comparable mortality rate. By contrast, patients with larger hematomas showed significantly lower mortality rates after operation but had no better functional recovery than the medically treated group. This effect from surgery was limited to patients in a preoperatively alert or somnolent state; stuporous or comatose patients had no better outcome after surgery. The outcome of surgical patients with putaminal or thalamic hemorrhage was no better than for those with medical treatment; however, there was a trend toward better quality of survival and chance of survival in the operated group.

Adult↗
PubMed1988

[Cytology of the normal ciliary ganglion].

In view of the increasing importance of tissue cytology in the diagnosis of different diseases the authors studied 12 ciliary ganglions of patients without eye disease who had died at ages ranging from seven months to 76 years. After preparation of the ganglions from the retrobulbar tissue, two different methods were used, i.e., the abklatsch and sedimentation methods. Only a small number of cells could be obtained by abklatsch preparation because the ganglion cells were difficult to separate. With sedimentation, however, excellent results were obtained relating to the morphology of the ganglion cells and their satellite cells. Three types of ganglion cells were distinguished, which differed in size and in their reaction to May-Grünwald-Giemsa staining.

Cytoplasm↗
PubMed1988

[Initial description of a retinal ganglioglioma].

Gangliogliomas are very rare neuronal tumors, predominantly localized in the thalamus, third ventricle, and temporal lobe. They usually occur in younger patients, grow slowly, and their glial components may develop to malignancy. A case is reported in which a tumor was detected on the upper rim of the optic disk. The patient was then four years old. Five years later the eye hat to be enucleated because of increasing growth and vascularization of the tumor. Histologically, it consisted of mature ganglion cells and neoplastic glial cells. Six years later, in addition to the glial hamartoma, a vascular hamartoma, i.e., a hemangioblastoma of the cerebellum, was found, this tumor was extirpated.

Biomarkers, Tumor↗
PubMed1988

Laser angioplasty with a contact probe for the treatment of peripheral vascular disease.

Percutaneous transluminal laser angioplasty was carried out for the dilatation of 30 completely occluded peripheral arterial segments and three subtotal stenoses. A neodymium-YAG laser and an optical fibre delivery system with a sapphire tip were used. All three arterial stenoses and 26 of the 30 occluded arterial segments were successfully dilated. In 20 patients additional dilatation was carried out with a balloon catheter. Laser angioplasty failed to recanalise four occlusions, and vessel leakage without clinical consequences occurred in one patient. Reocclusion occurred within 48 h in two patients and after five months in one patient during a follow up period of at least six months. It is concluded that percutaneous transluminal laser angioplasty using direct contact with a sapphire tip is highly effective (89% success rate) in reopening peripheral vascular occlusions. The procedure is safe, and reocclusion of vessels is rare during the six month follow up period.

Adult↗
PubMed1987

Giant fibroma of the lung. A morphological study.

The authors report the case of a 78-year-old male patient with an inoperable giant lung tumour diagnosed 5 years prior to death. Fine needle cytological examination at that time was interpreted as indicative of malignancy. In the following years the tumour grew very slowly without signs of infiltration or metastatic spread. On radiological examination sharp limitation of the tumour was evident. Recurrent pleural effusions occurred and the patient died from cardiorespiratory insufficiency. Autopsy revealed a giant fibroma, well vascularized but without signs of malignancy. The diagnosis was confirmed by immunohistochemical and electron microscopic examinations.

Aged↗
PubMed1987

[Laser angioplasty of peripheral arterial occlusions. Experimental and clinical results].

The first in-vivo trials were carried out on arteries of the extremities which have a straight course and short segmental occlusions. Initial experience indicates that obstructions up to 20 cm in length can be overcome by burning through plaques and thrombotic material by means of a neodymium-YAG-laser and then recanalised. By using a 2.2 mm spherical sapphire, one obtains a channel of 2.5 mm diameter through the obstruction. Subsequently dilatation with a balloon catheter is necessary. Laser angioplasty does not complicate the procedure significantly as far as the patient is concerned, since both the laser catheter and the balloon can be introduced through the same No. 7 F introducer into the femoral artery. Peripheral emboli could not be demonstrated angiographically, nor were they clinically manifest. On the basis of present experience, it seems that recanalisation of occlusions in arteries in the extremities, using a neodymium-YAG-laser focused by a synthetic sapphire, is a feasible alternative to conventional mechanical recanalisation.

Arterial Occlusive Diseases↗
PubMed1987

Effect of intracranial pressure on bridging veins in rats.

The behavior of bridging veins at their entrance into the superior sagittal sinus during elevated intracranial pressure (ICP) was investigated in rats using a cranial window and infusion of mock cerebrospinal fluid. The bridging veins became slightly smaller as the ICP rose (maximum reduction 17%). Compression or collapse of the veins was not observed, even at an ICP level of 100 mm Hg, and there was no cuffing of bridging veins upstream of the entrance. Both the scanning electron microscopic investigation based on resin vessel casts and the histological examination of whole-head coronal sections indicated that the narrowest points of the bridging veins are at their entrance to the superior sagittal sinus, caused by the oval aperture with thickened wall structure in the lateral sinus wall to which the bridging veins are connected. The present data thus support the concept that cerebral blood flow during intracranial hypertension is not reduced by venous cuffing or compression of the lateral lacunae and bridging veins; by contrast, the arteriovenous pressure difference seems to remain the determining factor even at high ICP. Thus, blood flow through the brain stops when ICP approaches the level of blood pressure.

Animals↗
PubMed1986

[Fatal eosinophilic meningoencephalitis following lacquer poisoning. Case report and differential diagnostic considerations].

The authors report about a 43-year-old male patient, who suffered from an acute toxic brain injury. Twelve days prior to death, after sealing his floor, he experienced progressively increasing headache without fever; the CSF examination disclosed marked eosinophilia. The clinical and pathomorphological features of his illness are discussed and together with the various possible etiologies of eosinophilia in the CSF.

Adult↗
PubMed1986

Regeneration in vascularized and free nerve grafts. A comparative morphological study in rats.

The regeneration of vascularized nerve grafts was compared with conventional free "cable" grafts. For the creation of a vascularized femoral nerve graft in the rat an arteriovenous fistula was constructed to overcome blood flow problems. The histo-morphological results showed better and more rapid regeneration in the group with a vascular pedicle. The arteriovenous fistulae were all patent even after five months.

Animals↗