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Biomedical subjects

R Lehmann

Publications and source records attributed to R Lehmann.

At least 271 records · Page 15Linked to original sources
PubMed1980

Alteration of chromatin in early experimental arteriosclerosis.

Our approach serves several purposes: To demonstrate the response of aortic cell nuclei to a changing environment (e.g. hypercholesterolemia, experimental diabetes, drug treatment), to apply the acridine orange (AO) ultracytochemical method, and to determine the euchromatin/heterochromatin (EU/HET) ratio by morphometric procedures as suitable criteria, and to emphasize the differential nuclear activity of adventitial cells. Hypercholesterolemia in rabbits results in an increase of AO positive nuclei in the adventitia. Additional treatment with tinofedrine, a new cerebral vasodilator drug, reveals an even higher number of AO positive nuclei in adventitial and also in endothelial and plaque cells. In streptozotocin induced diabetes in rats the increased number of AO positive cells coincides with an elevated EU/HET ratio.

Animals↗
PubMed1980

[Cervical root avulsion in metrizamide myelography].

Until now, the demonstration of cervical root pockets after root avulsion by means of the oily contrast medium Pantopaque has been considered to be the method of choice. Since Pantopaque usually cannot be completely tapped from the cerebrospinal fluid space and the authors have gained comprehensive and good experiences with the new water-soluble contrast medium Amipaque we have used this also for the demonstration of such empty root pockets. Technically, we have used the lateral cervical fluid space puncture between the first and the second cervical vertebra. The patient is placed in a lateral position, the pelvis slightly elevated and the head padded with a pillow. The cervical vertebral column is thus given a slightly lateral curvature, the root pockets from the deepest point, so that the contrast medium Metrizamide can run into them. Sometimes tomography is used. When treating a baby, the lateral cervical puncture was performed with the patient lying in a prone position, so that the root pockets could be demonstrated on both sides.

Diagnosis, Differential↗
PubMed1979

Distribution patterns of DNA template activity in the embryonic tooth organ: an acridine orange ultracytochemical study.

The ultracytochemical acridine orange (AO) method has been employed to demonstrate DNA template activity within embryonic incisor tooth organs excised from New Zealand White rabbits during the 25th day of gestation. Survey ultrastructural examination revealed characteristic distribution patterns of AO positive cell populations in the inner and outer enamel epithelium and the adjacent ectomesenchyme of the cervical loop region and in populations of fibroblast-like cells connecting as a band the outer AO positive cell groups. With increasing differentiation of ameloblasts and odontoblasts the number of AO positive cells as well as the number of AO chromatin interaction products per single cell nucleus decreased. Treatment with RNase prior to incubation with AO did not result in a noticeable loss of AO chromatin interaction products suggesting that RNA is negligible as a target for AO. The present results and comparison with other biological system indicated that interaction of AO with DNA sites coding for RNA appears to be restricted to specific templates in particular physiological conditions, e.g., stimulation of cells prior to differentiation by extracellular factors.

Acridine Orange↗
PubMed1979

[The use of organic bone matrix as material for direct pulp capping].

The effect of bone matrix soaked in thyrocalcitonin on vitally amputated pulp was studied in beagle dogs with light and electron microscopy. All treated teeth were vital after eight weeks; the area of implantation was densely populated with cells. Formation of hard tissue differing from normal dentinogenesis had begun.

Animals↗
PubMed1979

DNA template activity in the arterial wall of hypertensive rabbits.

With a new method employing acridine organe (AO) as an ultracytochemical probe DNA template activity could be visualized within cell nuclei of the thoracic aortic wall of rabbits. After experimentally produced chronic renal hypertension nuclei with a relatively high number of AO chromatin interaction products were found in the endothelium, in the intimal region, in the outer third of the media, and in the adventiia indicating increased DNA template activity. This representative distribution pattern of DNA template activity was not found in comparable regions of the thoracic aorta of normotensive rabbits. The results are consistent with the current concept that cellular response to environmental stimuli occurs via activation of previously repressed genes.

Acridine Orange↗
PubMed1978

[Diagnostic classification of intracranial meningiomas in the serial angiogram].

On the basis of 70 serial angiograms of surgically and histologically reliably diagnosed intracranial meningiomas and the appertaining general radiographs of the skull the following was found: 48.5 per cent of the general radiographs showed reactions, 7.1 per cent showed tumour calcifications. Basal meningiomas of the anterior and medium cranial fossae and meniogiomas of the wings of the sphenoid bone are supplied by the a. carotis interna, that is to say, they are also diagnosed by the internal carotid angiography. In serial angiograms, classification was possible in 74 per cent. The other supratentorial meningiomas require angiographies of the external or the common carotid. Infratentorial menigiomas were diagnosed in 50 per cent of the angiograms. The "early vein" is no reliable sign of malignity of the menigiomas. The same applies to "apthologic vessels", "shunts", etc. Staining does not give any secure indications of histological structures.

Cerebral Angiography↗
PubMed1978

[Meningiomas from the clinical viewpoint of first symptoms, duration of anamnesis and neurologic-ophthalmologic deficiency symptoms].

UNLABELLED: First symptoms, period of case history, neurological findings and ophthalmological findings were evaluated in 123 patients operated on because of meningiomas. Typical first symptoms were headache (42%), fits (30%) and impaired vision (28%). 70 per cent of the patients showed a case history period of up to two years, 11 per cent one of more than five years. In 25 per cent this period was less than six months. In two cases the symptoms set in an acute form. Paresis was found in cases of meningiomas of the falx convexity region. A papilledema was found in 41 per cent, reflex differences in 30 per cent and hemiparesis in 13 per cent of the patients. LOCATION: parasagittal (28 patients), falx (10 patients), convexity (31 patients), tentorium (6 patients), posterior cranial fossa (4 patients). Neither a short period of the case history nor the absence of neurological and ophthalmological changes can exclude a meningioma.

Adult↗