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B Laurent

Publications and source records attributed to B Laurent.

At least 127 records · Page 7Linked to original sources
PubMed1984

Immunogenetics and immunopathology of human primary membranous glomerulonephritis: HLA-A, B, DR antigens; functional activity of splenic macrophage Fc-receptors and peripheral blood T-lymphocyte subpopulations.

In most of our patients with idiopathic membranous nephritis (MGN), we have studied the HLA-A, B, DR phenotype, the clearance of anti Rhesus D coated-51 Cr-labeled-autologous erythrocytes, and the peripheral blood T-lymphocyte subpopulations as ascertained by monoclonal antibodies (OKT3, OKT4, OKT8). The frequency of HLA-B8 antigen is 57.14% in 28 primary MGN versus 14.4% in 104 local controls (Pc less than 0.00018). The frequency of HLA-DR3 antigen is 65.38% in 26 primary MGN patients versus 20.27% in 74 local control individuals (Pc less than 0.00008). The half-life of sensitized erythrocytes is 37.30 +/- 9.55 min in 10 controls, 1963 min and 1601 min in 2 splenectomized controls, 12 min in a patient with hypersplenism, and 67.05 +/- 69.64 min in 18 idiopathic MGN patients respectively. The half-life is significantly prolonged in 6 out of 18 MGN patients. This prolongation correlates with exacerbation of the disease while normal values are obtained with remission. The OKT3 positive subpopulation (total T-lymphocytes) is 63.77 +/- 10.37% in 31 controls versus 53.74 +/- 13.81% in 22 MGN (P less than 0.002). The OKT4 positive subpopulation (helper T-cells) is 37.90 +/- 8.21% in controls versus 32.79 +/- 10.89% in MGN (P less than 0.03). The OKT8 positive subpopulation (suppressor T-cells) is 21.60 +/- 5.28% versus 20.03 +/- 5.76% respectively. The OKT4/OKT8 ratio is 1.85 +/- 0.58 in controls versus 1.74 +/- 0.69 in MGN. During exacerbation, the T-lymphocyte subset fractions are normal, whereas OKT3 and OKT4 are decreased during remission. MGN is a strongly HLA-linked disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1984

[Dietary fiber].

Explore the source record for details and available documents.

Dietary Fiber↗
PubMed1983

[Cataplectic falls disclosing hypercalcemia].

Clinical manifestations of hypercalcaemic encephalopathy were heralded in three patients by isolated cataplexy-like falls without loss of consciousness. In one patient the falls with global hypotonia occurred every 5 to 10 seconds and were unaccompanied by changes in E.E.G. The falls disappeared after hypercalcaemia was corrected by excision of a parathyroid adenoma in two patients and by calcitonin injections in one. For this reason, there is little doubt that they were due to the hypercalcaemia, but their mechanism is poorly understood; it probably involves metabolic disturbances in the reticular systems of the brain stem. The connections between calcium metabolism and neuromediators in the brain stem are discussed.

Adenoma↗
PubMed1983

Structure and tissue distribution of some retinoid-binding proteins.

Vitamin A has, apart from its function in the visual pigments, general effects on several organs. Early signs of vitamin A deficiency include keratinization of epithelia and hyperkeratosis of the skin. To elucidate a generalized function for vitamin A, we have taken the approach of tracing the vitamin from its storage site in the liver via its blood transport by the retinol-binding protein (RBP) to its uptake by susceptible cells. We have also examined the intracellular occurrence of vitamin A as regards its binding to specific receptor proteins. Here we summarize data on the amino acid sequences of several vitamin A-binding proteins. The finding that CRBP and CRABP, the two intracellular proteins, are homologous to each other, to a myelin protein, and to a fatty acid-binding protein may shed light on the functions of these proteins. Retinoic acid, which binds to CRABP but not CRBP, induces differentiation of teratocarcinoma cells. This is accompanied by a lowering of the CRABP concentration, an increase of the CRBP level, and an increase in the uptake of retinol from RBP. The epidermis contains both CRBP and CRABP, and their distributions are rather similar. However, in contrast to CRBP, CRABP is most abundant in cells lining the hair follicles. CRBP occurs in greatest relative amounts in the outer layers of the epidermis. Since techniques have been developed to measure CRBP and CRABP, normal and disease-affected skin may now be explored as to quantity and cellular distribution of the retinoid-binding proteins.

Amino Acid Sequence↗
PubMed1983

Immunogenetics and immunopathology of human membranous glomerulonephritis.

In most of our membranous glomerulonephritis (MGN) patients, we have studied the HLA-A, B, DR phenotype, the clearance of anti-D rhesus coated 51Cr-labelled autologous erythrocytes, and T-lymphocyte subpopulations with monoclonal antibodies (OKT3, T4, T8). The frequency of B8 antigen in 28 patients with MGN (five cases associated with lupus excluded) is 57.14 per cent versus 14.42 per cent in controls (Pc = 0.0002). In 26 patients the frequency of DR3 antigen is 65.38 per cent versus 20.27 per cent in controls (Pc = 0.00008). The half-life of sensitised erythrocytes is respectively 35.36 +/- 8.50 minutes in nine controls and 67.05 +/- 69.64 min in 18 patients with MGN. The half-life is significantly prolonged in one-third of the patients at time of exacerbation. The peripheral blood T-lymphocyte subsets study showed a significant decrease of OKT3 and OKT4 positive cell subsets. T4/T8 ratio is high during exacerbation of disease and diminishes in remission. Our data are consistent with a latent subtle genetic immunodeficiency, only expressed during acute phases of the disease.

Antibodies, Monoclonal↗
PubMed1983

[Biological, psychometric and tomodensitometric study of treated neurosyphilis].

Results of follow-up examinations of the CSF in 6 patients with neurosyphilis, including 5 with general paresis, following treatment with high doses of aqueous penicillin G are reported. Persistence of any residual active infection of the nervous system could be eliminated since as well as fairly rapid restoration of normal CSF cytology and chemistry there was a slow reduction (and sometimes return to normal) of initially very high levels of immunoglobulins G, disappearance of their oligoclonal distribution (3 cases), and negativation of quantitative immunofluorescence serology (F.T.A. ABS). Clinical efficacy of treatment was shown by stabilization of the intellectual deficit investigated by serial psychometric tests. Memory disturbances were prominent mainly in the initial stages, and sometimes adopted a rather frontal nature. Psychometric tests can contribute to the assessment of initial extension of the treponemic infection in the aborted types of general paresis. The atrophy observed constantly on CT scans appeared to be stationary on serial examinations (2 cases). It was of a diffuse type affecting cortical sulci and ventricles. The onset of anomalies such as ischemic complications was not related to recurrence of infection.

Adult↗
PubMed1983

[Immunogenetics of intercapillary glomerulonephritis due to IgA deposits].

Idiopathic mesangial IgA nephritis (Berger's disease) and Schönlein-Henoch purpura mesangial IgA nephritis (SHP) have a common immunopathological pattern. There is a weak association with the MHC class I antigen, B35, which is a poor prognosis marker in Berger's disease and which predisposes to renal involvement in SHP. There is also an association with the MHC class II antigen, DR4, whose signification remains unclear. Many familial cases of Berger's disease have been reported in patients bearing the HLA-B35 antigen. We proposed that Berger's disease and SHP should be viewed as a unique entity according to their common immunogenetics and also common immunopathology.

Capillaries↗
PubMed1982

[Circulating immune complexes, detection in human glomerulonephritis by the PEG-EDTA technique (author's transl)].

In a prospective study, we screened sera samples of 128 patients with glomerulonephritis (GN) for the presence of circulating immune-complexes (CIC) fixing C1q by precipitation of native C1q with 2% polyethylene glycol (PEG) in the presence of 10 mM EDTA. The amount of precipitated C1q, as measured by Mancini, is less than 27% (m +/- 2 SD) of the original value in control sera. We found 35/128 (27%) positives samples, distributed as follows: 4/17 (24%) in acute GN, 10/15 (67%) in SLE, 2/16 (13%) in membraneous GN, 13/24 (54%) in membranoproliferative GN, 3/16 (19%) in segmental focal hyalinosis, 2/10 (20%) in minimal lesions nephrotic syndrome, and 1/30 (3%) in mesangial IgA GN. We then correlated these results with clinical, serological and pathological data. Whatever the type of GN, the presence of CIC fixing C1q correlated significantly, well with : the presence of chronic renal failure (serum creatinine greater than or equal to 2 mg/dl) (X2 = 5.48, p less than 0.02), the presence of hypocomplementemia (X2 = 12.30, p less than 0.001), the presence of low serum C3 (X2 = 8.25, p less than 0.01), the activation of C3 through normal pathway (low serum C4 and/or C1q) (X2 - 18.12, p less than 0.001) and the presence of glomerular deposits of C3 (X2 = 8.52, p less than 0.01), of C4 (X2 = 7.10, p less than 0.01), and of C1q (X2 = 4.11, p less than 0.05). The technique is simple, does not require labeled C1q, and allows the further study of antigen or antibody determinants of the complexes. Its sensitivity is near that of the 125 I-C1q binding assay technique. Such routine screening is a major immunopathologic step in the investigation of human GN.

Adult↗
PubMed1982

[Left paramedian thalamic infarct. Memory and language study].

Unusual findings in a patient with a paramedian infarct of the left thalamus, shown by CT scan were the elective nature and long duration of memory disorders. Mild amnesia has been relatively stable for two years, and is apparent during tests as an anterograde verbal memory deficiency for all modalities (serial, associative, logical), without facilitation during learning or recall by semantic or phonologic cues. On the other hand, anterograde visual, gestual or tactile memory, and particularly retrograde verbal and visual memory are well retained. The worsening effect of verbal interferences on word learning is emphasized, whereas no similar phenomenon has been observed for visual material. The antero-internal thalamic lesion in the dominant hemisphere results in a memory disorder of a particular type which cannot be explained by the cognitive disorder, or by the very transient initial aphasic disturbance. Prolonged verbal amnesia with persistent reduction in fluency most probably results from a deficiency of specific incitation in using and memorizing verbal material, without other negligence phenomena. The role of the thalamocortical and particularly frontocingular connections are discussed, according to the semiology.

Association Learning↗
PubMed1981

[Acute, recent and sometimes persistent Mycoplasma pneumoniae infections associated with neurologic manifestations. Discussion of causal relations].

Neurological disorders associated with recent and sometimes persistent Mycoplasma pneumoniae infections were present in 9 patients, examined within the course of a year, during the 1980 epidemic in Saint-Etienne, France. Cases included 5 with acute polyneuritis, 2 with lymphocytic meningitis, 1 with a bilateral optic neuritis, and 1 with mild encephalitis presenting as an amnesic disorder. Causal relationships are examined with respect to semiological, biological, therapeutic and epidemiological data. Clinically an initial infection compatible with the mycoplasmic etiology and its time relationship with the nervous system lesion appear to be more significant than the inflammatory neurological symptoms and signs. It is often impossible to ascertain the efficiency of the antibiotic therapy, which thus cannot help to the aetiological diagnosis. From the biological point of view, though seroconversion by complement fixation test remains the basis of the diagnosis, it has been completed by the isolation of Mycoplasma pneumoniae in the blood of 3 of the patients, and by a longitudinal study of specific blood IgM levels in the 6 others. Presence in the CSF of these locally synthesised specific IgM during the early stages of the neurological disorders in 2 patients, constitutes a new significant fact for the physiopathological discussions and a basic fact to clarify the aetiological diagnosis. The concept of persistent infection is discussed with respect to the isolation of Mycoplasma pneumoniae in the blood at a late stage, and the abnormally long presence of high levels of specific serum IgM levels. This biological persistence does not always correspond to a chronic course of the clinical disease which was observed in only 3 of the patients. The mixed viral infection, present in 3 cases, is linked with immunity disorders due to Mycoplasma pneumoniae, which are mainly a cell immunity depression: this markedly complicates the analysis of causal relationships. Finally, the chronological order of the clinical and biological events remains of prime importance when studying each case individually, whereas epidemiological data are essential for establishing a posteriori that the neurological manifestations were true complications of the microorganism.

Acute Disease↗
PubMed1981

[Phenotype characteristics of 100 strains of Pseudomonas cepacia. Proposition of a biovars classification (author's transl)].

The authors compared the phenotype characteristics of 100 strains of Pseudomonas cepacia mostly of hospital origin to those of the typical mother strain (ATCC 25416). The morphological, cultural and biochemical characteristics (oxidase characteristics, ONPG, LDC, gelatinase and esculine were generally positive), nutritional characteristics (use of numerous organic compounds) and the antibiotypes (usually resistant to betalactamines, aminosides, polymyxins, tetracycline and furans) are reported, together with the differential diagnostic problems between P. cepacia and P. maltophilia (TTR+ methionine requirement). P. pseudomallei (LDC-, ODC-, ADH+, ONPG-) and Agrobacterium sp (urease+, LDC-, ODC-, absence of exoenzymes and use of citrate and malonate). An original classification in 8 biovars (characteristics used : esculine, nitratase, ONPG) permitted epidemiological marking of the strains and a study of their distribution.

Humans↗
PubMed1981

[Motor negligence in a case of right thalamic hematoma (author's transl)].

In a patient with left motor negligence CT scan showed a right thalamic hematoma of small size, involving the posterior thalamic region. The clinical picture was pure, including neither marked distal or proximal motor deficiency, nor auditory or visual or somesthetic disorders except sensory extinction. Cortical somesthetic evoked potentials were normal. Motor negligence presented 3 basic elements: 1) lack of spontaneous movements of the left side of the body, particularly of the upper limb; 2) absence of nociceptive reactivity; 3) immediate total reversibility of the disorder following verbal commands. Emphasis is placed on this latter sign which indicates the thalamic origin of the disturbance. Of the various explanations proposed for the disorder the most likely one would appear to be a disorder of a relatively specific activation system of motor activities, a system arising from the posterior thalamic nuclei: 1) pulvinar and laterodorsal nuclei projecting over area 23 (posterior cingulum); 2) intralaminar formations, particularly the lateral superior central nucleus, projecting over area 24 (anterior cingulum). The disturbance in this system, at its thalamic origin, might explain the differences between this motor negligence behaviour and lack of spontaneous motility syndromes resulting from frontal cortical lesions. It might also be that the right lateralisation of the lesion plays a relatively minor role.

Diagnosis, Differential↗
PubMed1981

[Progression and severity of arterial hypertension in aged subjects (12 cases].

We analyzed retrospectively 12 patients, aged from 63 to 73 years, with renovascular hypertension due to unilateral or bilateral atheromatous lesions (4 out of 12). Malignant or accelerated hypertension with multiple visceral involvement was frequent (8 out of 12). The proximal lesions (stenosis) of the renal arteries were rapidly progressive, leading to complete thrombosis in 8 cases. Five patients received medical treatment only, but 2 worsened their GFR and 2 had a poor blood pressure control. Of the 5 patients who underwent renal surgery 2 had nephrectomy, 2 had an aorto-renal bypass and 1 a bypass plus nephrectomy; 2 of them recovered a normal GFR, but 2 died in the post-operative period. Three patients had selective embolization of a renal artery, but only one was definitely improved. So far, the treatment of such cases still is very difficult.

Aged↗
PubMed1981

[Effects of physostigmine on amnesic syndromes (author's transl)].

Eserine sulphate (physostigmine) tests were conducted in 23 patients with amnesia due to cerebral lesions. Psychometric examinations were performed before and after treatment. Results were analysed statistically for the whole group, and after distribution of patients as a function of the etiology, of the mechanism involved, and of the presumed lesions: 1) amnesias related to lesions along Papez' circuit as shown on CT scans were compared with those with normal CT scans; 2) amnesias of the "hippocampic" types were compared with other neuropsychological types. After eserine sulphate learning ability rapidly improved, in all cases, whereas spontaneous or assisted recall was only slightly improved. No significant differences in learning or recall were noted between the group with normal CT scans and that with evidence of bilateral lesions. In contrast, the efficiency of physostigmine was clearly related to the nature of neuropsychological disorders both for learning and recall of verbal material : a positive effect occurred only in the group with obvious evocation and recall disorders (mamillary, thalamic, or cingular lesions). For improvement to occur the product had be be injected before learning. The role of cholinergic mediators in memory is discussed with regard to these observations. Overall benefit was poor since lasting improvement in fixation was noted in one case only. Thus eserine sulphate appears of little value for prolonged therapy. It may be useful for a functional test during neuropsychological investigations.

Adult↗