[Interpretation of and indications for bone scintiscans]

The interpretatiton of a bone radioisotope scan requires perfect knowledge of normal skeletal appearances, shadows outside the bones and the various methods of expression of bony lesions: generally hyperfixations but sometimes isofixations or even hypofixations. A bone scan permits one to make an overall assessment of multiple bony lesions, determine the extent of a lesion, detect bony complications of a disease or treatment and seek the bony origin of a pain.

Glycosphingolipids from cultured astroblasts

The glycolipids of two clonal lines astroblasts, NN clone and C6 clone, were studied. Glucosylceramide and lactosylceramide were present at very low levels in both clones, but the most common myelin glycolipids galactosylceramide and sulfatide, were not detected. The ganglioside pattern of these cells was rather simple, with GM3 as main compoenent, accompained in one clone by GD3. These results are quite different from those observed on astroglia-enriched fractions isolated from brain. The fatty acid composition of these glycolipids was studied. Long chain fatty acids, up to lignoceric acid, were found in appreciable amounts, even in gangliosides. It is difficult to conclude if these glycolipid patterns are due to the properties of normal astroblasts, to transformation, or to a tumoral character of our cell lines.

Essential fatty acid metabolism in cultured astroblasts

The fetal calf serum on which two astroblast cell lines were grown was shown to be deficient in essential fatty acids. The fatty acid profiles of lipids of these two cell lines showed very low amounts of polyunsaturated fatty acids. In order to know if this low level of unsaturation was due to the lack of essential fatty acids in serum, or to a lack of desaturase activities in the cells, we have investigated the modifications of the cell lipid fatty acid patterns when serum was enriched in essential fatty acids. Linoleic acid was incorporated in rather high amounts in the cell lipids, while linolenic acid was very poorly incorporated. These two essential fatty acids were converted into polyunsaturated fatty acids only when they were added alone to the serum. Both cell clones exhibited a lack in the delta 4 desaturase activity. No morphological changes of the cells occured after nine days of culture with modified serum.

Gangliosides of active and inactive neuroblastoma clones

It is possible to divide neuroblastoma cells into clones able to synthesize neurotransmitters (active clones) or not (inactive clones). The analysis of gangliosides of active and inactive clones shows that their total lipid sialic acids is markedly lower than that of neuron-enriched fractions prepared from brain. The ganglioside pattern of the cultured cells also differs notably from those obtained with neuronal fractions from brain. The absence of tri- and tetrasialogangliosides and the presence of appreciable amounts of the simplest monosialogangliosides are particularly noticeable in the neuroblastoma. Morphological differentiation obtained by serum deprivation, dibutyryl cyclic AMP or bromodeoxyuridine does not restore a true neuronal pattern. Gangliosides could not therefore be used as a marker of neuronal differentiation in this type of cell. No correlations can be found between the ganglioside pattern and the ability of cells to synthesize neurotransmitters.

[Diagnostic value of localized hypofixations in the radioisotope scanning of bones]

The scintigraphic appearances of all localized, evolutive bone lesions, whatever their nature, is usually a "hot spot", that is a zone of hyperfixation of the radioactive material. False negatively scintigraphs are, however, noted: the scintigraphic image appears normal, without a zone of hyperfixation, although radiographs of the skeleton are pathological. The 8 cases presented in this article demonstrate that certain bone lesions (aseptic osteonecrosis and malignant destruction of bone) may sometimes be represented as real zones of hypofixation, as veritable "cold spots". These areas of hypofixation result from either a local interruption in the vascularization, which prevents the isotope from reaching the bony structures, or from a quantitative insufficiency of the bony tissue, this being replaced by neoplastic tissue which, in the cases studied, fixed labelled Bleomycin or iodine-131. These areas of hypofixation and any absences of fixation really are the scintigraphic images of areas of osteolysis or of aseptic osteonecrosis but they are generally masked by hyperfixation around the lesion that results in reactional osteogenesis and hypervascularization.

Catecholamine histofluorescence in the median eminence of female rabbits activated by mating

Mating was used in the rabbit as a physiological trigger, easily definable in time, for the activation of gonadotropic hypothalamic structures. Using the histochemical fluorescence technique of Falck and Hillarp, it has been attempted to determine whether, in relation to mating, clearly distinuishable and reproducible changes in histofluorescence occur in the tuberoinfundibular dopaminergic system in combination with hypothalamic hypophysiotropic hormone release. Between 20-30 min post-coitum an increase in DA turnover was noted in the external layer of the median eminence. The characteristics of this reaction were studied by administration of reserpine and alpha-methyl-paratyrosine. Immediately after coitus, a paradoxical fluorescence reactivation was observed in the median eminence in female rabbits in which tyrosine-hydroxylase activity was inhibited for 5 hours.

Nematic liquid crystal 1024 bits page composer

We report design considerations and experimental results concerning a nematic liquid crystal (NLC) cell used in an ac crossbar addressing mode to achieve a page composer for holographic memories. Our display is a 32 x 32 binary elements page composer utilizing the electrooptic (EO) effect of index modulation or field effect in an homeotropic NLC cell, and this composer acts as a spatial wave polarization modulator.

Use of radioactive bleomycin to detect malignant intracranial tumors. Comparative study with technetium-99m in 104 cases

✓ A new isotopic method for the detection of cerebral tumors using labeled bleomycin is described. In a series of 104 patients, bleomycin was found superior to technetium-99m for the diagnosis of intracranial metastatic lesions; in 50% of the cases, bleomycin revealed metastases undetected by the Tc-99m, particularly in the posterior fossa. This method also provides valuable data for the differentiation of gliomas from metastases.

Detection of Australia antigen in liver biopsies by immunofluorescence

A search for Australia antigen (AuAg) was made by immunofluorescence in 105 liver biopsies obtained from the same number of patients. No specific fluorescence was observed in 38 cases of acute viral hepatitis (19 of them seropositive for AuAg) or in 55 seronegative patients with various liver disorders or in 8 seronegative patients with histologically normal livers. However, specific fluorescence was seen in two cases: in the single case of chronic aggressive hepatitis seropositive for AuAg and in one of three cases of chronic persistent hepatitis with AuAg-positive sera. The fluorescence observed was mainly intranuclear when cellular suspensions were used, but cytoplasmic fluorescence was more prominent when observations were made on cryostat sections. The finding of AuAg by immunofluorescence in liver cells in chronic but not in acute forms of hepatitis seropositive for AuAg is consistent with the hypothesis of an important role of cellular immunity directed against infected cells in the pathogenesis of viral hepatitis.