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C Masson

Publications and source records attributed to C Masson.

At least 181 records · Page 10Linked to original sources
PubMed1990

A 116,000 Mr nucleolar antigen specific for the dense fibrillar component of the nucleoli.

In ATT, a human autoimmune serum, we found anti-nucleolar antibodies that recognized nucleolar antigens confined to a single nucleolar compartment, the dense fibrillar component (DFC). We localized these antigens by immunoelectron microscopy in DFC of HeLa cell nucleoli both on Lowicryl sections and cryoultrathin sections without embedding. The antigens were solubilized by incubation with 2M NaCl but not by RNase or DNase treatment. The ATT serum crossreacted with rat liver nucleoli and PtK1 cell nucleoli in which immunofluorescence labelling displayed a clumpy pattern. During mitosis, the antigens dispersed in the cytoplasm until late telophase, when they gathered in the prenucleolar bodies. In human peripheral lymphocytes, or HeLa cells treated with actinomycin D, the antigens were still present but the fluorescence intensity decreased. By immunoblotting using human nuclear extracts, the ATT serum bound to a 116,000 Mr protein at dilutions up to 1:2000. The reactivity of this band diminished with actinomycin D-treated nuclear extracts. Two minor bands were also observed at 97 and 70K (K = 10(3) Mr). Immunopurification by competition or elution demonstrated that the 116K antigens were at the origin of the nucleolar labelling. This DFC marker appeared to be different from the NOR-silver-stained proteins, which in our preparations exhibited apparent molecular weights of 105, 80 and 38-40K. In addition, these 116K antigens did not exhibit the characteristics described for DNA topoisomerase I, fibrillarin or nucleolin. We propose the 116K antigen as a new marker of the DFC of the nucleoli.

Aged↗
PubMed1990

[Clinical application of grafts of cultured epidermis in burn patients. Apropos of 16 patients].

The authors report a series of 16 patients with extensive burns partially treated by epidermal culture between May 1985 and July 1988. This series consisted of 9 males and 7 females between the ages of 6 and 88 years (mean age: 34 years). The mean surface area of the burns was 66% (range: 30% to 92%). The technique of epidermis culture used was derived from that developed by Green and Rheinwald. A fragment of full-thickness skin taken from the patient was subjected to the action of trypsin. The keratinocytes were cultured on nutrient layers of 3T3 cells. After 10 days, the secondary cultures corresponded to stratified squamous epithelium with a differentiation similar to that of normal human epithelium. This cultured epithelium was used for autografts as well as allografts. Three deaths were related to septic or metabolic complications of the burn. The take rate of the initial graft was greater than 50% in 9 patients. In 3 patients the graft take rate was less than 50% and in 4 patients it was nil. The long-term evaluation of 12 patients revealed partial lysis of the grafts in 3 patients, a stable result in 6 patients and a healed surface greater than the grafted surface in three cases. The best results were obtained with autografts. The initial evaluation of taking of the graft is difficult, as the fine and shiny texture of the grafts is sometimes difficult to distinguish from non-covered zones. The good tolerance of cultured epidermis allografts is due to the fact that they are devoid of Langerhans cells. Although controversial, the reality of the taking of these allografts opens the way to establishing epidermis culture banks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Physiopathologic mechanisms of coma].

The occurrence of coma betrays a deficiency of the ascending reticular activating system (ARAS) of the brain stem, which constitutes the neurophysiological support of wakefulness. Multiple factors, acting separately or jointly, may be responsible for coma. They include diffuse lesions or circumscribed lesions with repercussions on the ARAS metabolic and toxic factors, intracranial hypertension, cerebral oedema, epileptic activity, and so forth. Owing to the influence it exerts on the management of coma, the physiopathological approach is as necessary as the aetiological approach.

Brain Diseases↗
PubMed1989

Three-dimensional organization of micronuclei induced by colchicine in PtK1 cells.

In PtK1 cells micronucleated by colchicine, we previously demonstrated that some micronuclei contain a single chromosome. Here, we investigated interphase chromosome organization in micronucleated PtK1 cells using conventional electron microscopy and three-dimensional computer reconstruction. The distribution of micronuclei was not always polarized, but in some cells they formed a ring. When this occurred, centrioles and Golgi apparatus were located inside the ring. On freeze-fracture replicas, we observed that nuclear pore distribution among the micronuclei was heterogeneous, and on thin sections some micronuclei displayed an incomplete nuclear envelope, with gaps in the double membrane and areas without lamina or condensed chromatin. By autoradiography, we showed that the fibrillar dots were not sites of active transcription. We applied three-dimensional reconstruction to one micronucleated cell containing 22 micronuclei whose size indicated that each micronucleus probably contained one chromosome. In this cell we demonstrated that only the smallest micronuclei had an incomplete nuclear envelope. The presence in micronuclei of either nucleoli or fibrillar dots was found to be mutually exclusive. These dots might constitute stores of nucleolar proteins which migrate into micronuclei possessing no ribosomal genes. In NOR-bearing micronuclei, the structural organization was similar to that of diploid nuclei: the nucleoli were attached to the nuclear membrane and a nucleolar canal was seen, even in single-chromosome spherical micronuclei. Taken together, these findings indicate that in the diploid nuclei of PtK1 cells, the three-dimensional organization of the nucleolar domain seems to be directly controlled by the X-chromosome.

Animals↗
PubMed1989

Long-acting propranolol in migraine prophylaxis: results of a double-blind, placebo-controlled study.

The efficacy and safety of long-acting propranolol (LA.P), 160 mg once-daily, in the prophylactic treatment of migraine have been tested against placebo in a multicentric, double-blind, randomized study. The two groups are compared in a parallel manner over a treatment period of 12 weeks, following a 4-week placebo run-in period. Fifty-five of the 74 patients who entered the trial were included at the end of the run-in period. Forty-one patients completed the study. None of the 14 patients who withdrew from the study did so because of side effects. The statistical analysis was done according to the "intention to treat" principle. LA.P was significantly more effective than placebo in reducing the frequency of migraine attacks (p = 0.01 by variance analysis). LA.P reduced the average number of monthly crises by 48% on day 84. There was a slight but significant reduction of the systolic blood pressure and heart rate in the erect position, but there was no significant difference between LA.P and placebo regarding either the number of complaints or the number of side effects elicited out of a 17-item questionnaire. None of the observed side effects led to a withdrawal from treatment.

Adult↗
PubMed1989

[Quantification of a specific inhibitor (PAI-1) of tissue-type plasminogen activator (t-PA) in the plasma].

In human plasma, the activation of plasminogen by tissue plasminogen activator (t-PA) is a fibrin localized process which allows the specific dissolution of thrombi. Most of the t-PA circulates as a complex with its inhibitor, PAI-1, which thereby regulates its activity. In the present work the authors have studied the kinetics of inhibition of t-PA by PAI-1 and have developed an assay for its specific detection. The assay is performed in microtitration plates containing a solid-phase fibrin network, as follows: the source of inhibitor is mixed with solutions containing increasing amounts of t-PA, then the residual t-PA is separated by means of a solid-phase fibrin support and detected with a coupled reaction using a plasmin selective chromogenic substrate. The change in absorbance is measured in a microtiter plate reader and converted to t-PA activity by reference to a standard curve. The residual t-PA activity is inversely proportional to the concentration of PAI-1. The quantitation of PAI-1 is based on the variation of the dissociation constant of the fibrin/t-PA interaction obtained in the presence of the inhibitor. Since other serine-protease inhibitors do not interfere with the assay, the method is specific for PAI-1 and can be safely used in other biological fluids.

Adult↗
PubMed1989

[Cranial pachymeningitis of unknown origin. Study of 3 cases].

The clinical picture in three cases of chronic cranial pachymeningitis of unknown origin was dominated by headache, disturbed balance, a confusional state and cranial nerve lesions. The erythrocyte sedimentation rate was increased and the CSF showed inflammatory changes. CT scan imaging showed thickening of the tentorium cerebelli, which took up contrast intensely. Meningeal biopsy showed the dura-mater to be the site of a non-specific inflammatory process. No precise cause was found. Clinical manifestations in these three patients were remarkably corticosensitive but lesions did not regress on CT. The development of a state of corticodependence led to an attempt at treatment with radiotherapy and/or azathioprine, but follow up is insufficient to evaluate results.

Adult↗
PubMed1989

[Unilateral paralysis of saccades caused by pontine tuberculoma].

A unilateral lesion of the paramedian pontine reticular formation results in an ipsilateral laterality paralysis with abolition of all saccadic movements directed to the side of the lesion. It is generally accepted that the oculocephalic reflex alone enables the eyes to be deviated beyond the median line of the affected side. In the present case of a paramedian pontine tuberculoma, a paralysis of laterality in accordance with the above mentioned opinion was observed initially. Treatment led to recovery of an ipsilateral pursuit of normal amplitude, contrasting with the persistent abolition of ipsilateral saccadic movements. The significance of this dissociation is discussed together with that of the later reappearance of slow voluntary movements (slow saccadic movements) towards the affected side.

Adult↗
PubMed1989

[Myelopathy, polymyositis and systemic manifestations associated with the HTLV-I virus].

A case of HTLV-I associated myelopathy in a 51 year-old Haitian woman is reported. MRI showed high signals in the cerebral white matter on T2-weighted images. There also was clinical and electrophysiological evidence of myositis, and a biopsy of the quadriceps muscle showed dense inflammatory infiltrates surrounding several small perimysial blood vessels. The virus was not demonstrated in the muscle. The presence of several systemic abnormalities (polyclonal gammapathy, circulating immune complexes, Sjögren's syndrome) and the vasculitis suggest an immunopathological mechanism for this HTLV-I associated myositis.

Antigen-Antibody Complex↗
PubMed1989

[Myelin lesions in the central nervous system caused by disturbances in plasma osmolarity: pontine and extra-pontine myelinolysis].

Central pontine myelinolysis is defined by a symmetric area of myelin damage in the center of the basis pontis. In 10% of these cases, symmetric extra-pontine lesions of similar histological type are found in other parts of the brain. The MRI has provided information about the natural history of this demyelinating process. Disorders of plasma osmolarity appear to be a crucial factor in the pathogenesis of central pontine myelinolysis: rapid correction of hyponatremia or sometimes severe plasma hyperosmolarity. Alcoholic patients and, more generally, those afflicted with a serious debilitating illness are more susceptible to a hyperosmolar insult, absolute or relative. In such cases, the management of hyponatremia must be very cautious, owing to the risk of myelinolysis.

Adult↗
PubMed1988

Kinetic analysis of the interaction between plasminogen activator inhibitor-1 and tissue-type plasminogen activator.

The kinetics of inhibition of tissue-type plasminogen activator (t-PA) by the fast-acting plasminogen activator inhibitor-1 (PAI-1) was investigated in homogeneous (plasma) and heterogeneous (solid-phase fibrin) systems by using radioisotopic and spectrophotometric analysis. It is demonstrated that fibrin-bound t-PA is protected from inhibition by PAI-1, whereas t-PA in soluble phase is rapidly inhibited (K1 = 10(7) M-1.s-1) even in the presence of 2 microM-plasminogen. The inhibitor interferes with the binding of t-PA to fibrin in a competitive manner. As a consequence the Kd of t-PA for fibrin (1.2 +/- 0.4 nM) increases and the maximal velocity of plasminogen activation by fibrin-bound t-PA is not modified. From the plot of the apparent Kd versus the concentration of PAI-1 a Ki value of 1.3 +/- 0.3 nM was calculated. The quasi-similar values for the dissociation constants between fibrin and t-PA (Kd) and between PAI-1 and t-PA (Ki), as well as the competitive type of inhibition observed, indicate that the fibrinolytic activity of human plasma may be the result of an equilibrium distribution of t-PA between both the amount of fibrin generated and the concentration of circulating inhibitor.

Cells, Cultured↗
PubMed1988

[Serum, synovial and intra-articular pharmacokinetics of naproxen after one-gram oral administration in patients with rheumatoid polyarthritis].

After a reminder of the major points of the pharmacokinetics of non-steroid anti-inflammatory drugs, the authors report the results of a multicentric study of the kinetics of naproxen after oral intake of one single dose of 1 gram in patients with rheumatoid arthritis. The half-life is longer in the synovial fluid than in the serum, 23 hours versus 17 hours. The balance point is obtained at the 24th hour and, at that time, the naproxen level in the synovium and the joint fluid are 32 and 60 p. cent, respectively, of the corresponding maximum concentrations.

Administration, Oral↗
PubMed1988

Functional identification of t-PA in crude and purified systems.

In the present study the activation of glu-plasminogen by fibrin-bound t-PA was determined by integrating spectrophotometric and computer analysis of the reaction. Our aim was to determine the parameters of the activation and to characterize the functional activity of t-PA. Our results indicate that the t-PA present in purified or crude sources such as plasma or culture supernatants, can be specifically identified using the methodology described in this report.

Fibrin↗