Biomedical subjects
Publications and source records attributed to M Gregoire.
Pseudocyst formation is a well-recognized complication of pancreatitis. Involvement of a pseudocyst with the kidney is rare. We report an unusual case of a pancreatic pseudocyst with rupture into the renal collecting system. The surgical management of this problem is described and the world-wide experience is reviewed briefly.
Micronuclei have been induced by colchicine in rat kangaroo (Potorous tridactylis) PtK1 cells. The synthesis of RNA was investigated both in isolated micronuclei by quantifying RNA polymerase activities at different ionic strengths with or without inhibitors, and in micronucleated cells by radioautography after [3H]uridine pulse labeling. In vitro transcription shows that isolated micronuclei are able to take up [3H]UTP. The rate curves of incorporation are close to those of isolated diploid nuclei, though the level of incorporation was relatively lower (65-70%) than control nuclei. This indicates that micronuclei react to the ionic environment and to inhibitors in the same manner as described for many species of isolated diploid nuclei. The labelling distributions plotted from radioautographs show that micronuclei were able to efficiently incorporate the hot precursor. Furthermore, for short pulses there is no homogeneity in the labelling density among the different micronuclei and there is no correlation between the labelling intensity and the size of micronuclei. After 60-min pulse time, there is an enhanced uptake of [3H]uridine and all the micronuclei exhibit considerable labelling, although less than control cells. Thus, the micronuclei exhibit some characteristic RNA transcriptional activity in situ as well as after isolation. This material should be a particular interesting model with which to study the physiological activity and the role of each individual interphasic chromosome.
The effect of synthetic granular hydroxyapatite (HAP) on cultured fibroblastic cells (L929, human bone and gingiva cells) was studied. Phagocytosis of HAP particles and resulting morphological cell changes were demonstrated by microscopic examinations. Cell counts and [3H]thymidine uptake indicated significant increases in cell proliferation and DNA synthesis. These results could account for some of the alterations of the fibroblast behavior induced by changes in intracellular levels of calcium ions released from the material.
Serum proteins have never been described in enamel as they have been in dentin or bone where they are bound to apatite, may be because of the specific organic/crystal relationship which makes enamel crystals different from the other biological apatites. In the present study, crystals from bovine developing enamel have been isolated to test their ability to bind serum albumin in vitro. Those crystals, although naturally coated with enamelins proved to be able to bind gold-labelled serum albumin. Consequently, free binding sites exist at the surface of these biological crystals. It is suggested that the 'sheath' surrounding crystals in TEM observations is the fixed aspect of a dynamic process in vivo. Finally, the lack of blood proteins in enamel cannot be attributed to a particular property of enamel crystallites.
Chromatin distribution was visualized in living cells with the selective DNA fluorochrome Hoechst 33342. This dye was shown to be non-toxic on the rat kangaroo PTO cell line by measuring the labelled cell growth rate. The aim of this work was firstly to visualize chromatin distribution without fixation or dehydration and secondly to demonstrate that quantitative determination of DNA content was possible under these non-toxic labelling conditions. During interphase, condensed, decondensed and thin network chromatin configurations were visualized. In nucleolar regions the fluorochrome revealed well-defined chromocentres. During mitosis, fluorescent chromosome banding was observed in vital conditions and chromocentres on fixed chromosomes. Chromatin segregation was visualized after micronucleation, which induced chromosomal set distribution in individual micronuclei. By this means, we demonstrated that the chromocentres observed in interphase nuclei were part of nuclear organizer region (NOR)-bearing chromosomes. This vital staining of chromatin was shown to be compatible with the quantitative determination of DNA content, both in living PTO cells and in isolated nuclei.
We investigated the effects of DNA labelling by fluorochrome Hoechst 33342, on chromatin distribution and transcription during a short-term non-toxic staining procedure which did not prevent the cell growth. By electron microscope examination we found chromatin condensation and nucleolar fragmentation just after the staining. Both effects appeared to be reversible 24h after staining; 48h afterwards, the morphological pattern was similar to that of control cells. The rate of RNA transcription was reduced at the end of staining, increased at 24h, and was comparable to the control at 48h. We also observed an effect on the cell cycle when the staining pasted 6h. Consequently, 24h after Hoechst vital staining, the effects on chromatin vanished whereas the cells remained fluorescent.
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Follow-up of 102 patients operated upon for autonomous thyroid nodules is reported. Retrospective study of operative findings and aftermath of surgery clearly demonstrates that the patho-physiological concept of autonomous nodule does not snugly fit practical problems experienced with the management of such patients. The autonomous nodule can be a malignancy. Ipsilateral thyroid lobectomy seems more suitable than nodulectomy. Gross appearance of the thyroid remnant makes sometimes post-operative hormonotherapy unexpectedly advisable. From a theoretical point of view, post-operative thyroid scan, TSH assay and TRH test are mandatory, to assess recovery.
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The efficacy of the new anti-allergic compound oxatimide was tested in a double-blind study against a placebo during the pollen season of 1976 in 215 patients (4 1/2--69 years) with hay fever. Adult patients were instructed to take two tablets (= 20 mg) three times a day for 2 weeks, children received one tablet/10 kg of body weight daily; in addition, they were given a supply of diphenhydramine as a potential supplement. Twelve patients, six from either group, were excluded from the analysis. A significantly higher proportion of patients from the active drug group (n = 104) experienced no or only a few days of complaints, i.e. rhinitis and conjunctivitis, as well as asthma-like complaints, as compared with those of the control group (n = 99). Also, diphenhydramine consumption became significantly lower in the active drug group from the second day onwards, whereas a gradual increase and continuous need were seen in the greater part of the control group. One week of treatment appears sufficient to judge whether the individual patient benefits from the drug or not.
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Due to their resistance to classical chemotherapies, most human colorectal cancers have a high incidence and a poor prognosis. Immunotherapy using interleukin 2 (IL2) has provided disappointing results in the treatment of these cancers. Recently, however, we have demonstrated that a treatment combining a cell-differentiating agent, sodium butyrate (NaBut) with IL2 resulted in a remission of established peritoneal colorectal carcinomatosis in rats. Separately, neither NaBut nor IL2 treatment cured these tumour-bearing rats. NaBut is known to induce cell differentiation and subsequent apoptosis in epithelial cells, while IL2 stimulates the immune cells capable of participating in tumour rejection. We postulated that the significant therapeutic effect of NaBut/IL2 treatment could be attributed to a NaBut-induced increase in the immunogenicity of the cancer cells. We report here that NaBut induced an apoptotic process in rat colon tumour cells in vivo and in vitro. We observed, in an efficient cure, colocalization of apoptotic bodies and monocytes/macrophages at the periphery of the tumour. We propose that these apoptotic bodies are phagocytosed in vivo by the macrophages. We also showed in vitro that a subpopulation of macrophages involved in the phagocytic clearance of apoptotic cells expresses cell surface molecules associated with antigen presentation and stimulates the proliferation of naive splenocytes. Our data suggest that therapies that recruit massive induction of the apoptotic process in tumour cells could favour tumour antigen presentation via their specific phagocytosis by antigen-presenting cells (APCs). We propose that the development of specific therapies that stimulate both tumour cell apoptosis and the immune system could offer new opportunities in anti-cancer treatments of poorly immunogenic cancer cells.
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