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Biomedical subjects

G Dubois

Publications and source records attributed to G Dubois.

At least 19 recordsLinked to original sources
PubMed1992

Variation of choline-substituted lipid metabolism in doxorubicin-resistant leukemia cells.

In adriamycin-resistant murine (FLC) and human (K562) leukemia cells, phosphatidylcholine increases and phosphatidylethanolamine decreases compared to adriamycin-sensitive lines. This change is due to an increase in phosphatidylethanolamine methylation. The choline pathway of phosphatidylcholine biosynthesis is also disturbed in resistant cells with a blocking step of CDP-phosphocholine transferase and a decrease in sphingomyelinase activity. These changes in phospholipid metabolism are suggested to be responsible for the changes in membrane fluidity reported previously (Tapiero et al, 1986) for resistant cells.

Animals↗
PubMed1992

Comparison of the mutagenicity of quinoline and all monohydroxyquinolines with a series of arene oxide, trans-dihydrodiol, diol epoxide, N-oxide and arene hydrate derivatives of quinoline in the Ames/Salmonella microsome test.

Fourteen new quinoline derivatives were synthesised and their mutagenicity compared in the Ames test using Salmonella typhimurium TA100 as indicator strain with and without (Aroclor-induced) S9 mix. None of the synthesised quinoline derivatives had to our knowledge been examined before in the Ames test. Quinoline and the monohydroxyquinolines were included as reference compounds. Three of the new derivatives, i.e., quinoline 7,8-oxide, N-methyl-quinoline 5,6-oxide and trans-quinoline-5,6,7,8-dioxide appeared to be mutagenic. Quinoline 7,8-oxide was positive only in the presence of S9 mix, the specific mutagenicity amounting to 2498 +/- 96 and 1289 +/- 120 revertants per mumole with 20 and 10% S9 in the mix, respectively. Both N-methyl-quinoline 5,6-oxide and trans-quinoline-5,6,7,8-dioxide were weakly positive, the former only in the presence of the S9 mix, and the latter irrespective of the presence of S9 mix, the specific mutagenicity amounting to 134 +/- 6 and 123 +/- 10 revertants per mumole, respectively. The mutagenic potency of quinoline 7,8-oxide was of the same order as that of quinoline itself and was distinctly lower than that of 8-hydroxyquinoline. Inconclusive results were obtained with trans-7,8-dihydroxy-7,8-dihydroquinoline, 5,6-dihydroxy-7,8-epoxy-5,6,7,8-tetrahydroquinoline and 8-hydroxyquinoline-N-oxide; if these compounds are mutagenic their mutagenic potency would be at least 20-30 times lower than that of the parent compounds. None of the other chemically synthesised quinoline derivatives showed mutagenic activity with TA100 either in the presence or in the absence of S9 mix. The results obtained with the reference compounds were in accordance with literature data.

Animals↗
PubMed1992

The cranial base in subjects with dental and skeletal Class II.

The aim of this study was to test to what extent the cranial base variations may be involved in Class II facial organization. Using Bonferonni probabilities, cranial base size and shape, and facial divergence were compared in two groups: an experimental group of 45 subjects with dental and skeletal Class II and an homologous control group of 41 subjects with a natural Class I ideal occlusion. In all individuals of the experimental group the Class II molar relationship was at least equal to the width of one premolar and the ANB angle was greater than the value of the mean +2 standard deviations of the ANB in the control group. Spacing and crowding was less than 2 mm at each arch in both groups; all subjects were between 10 and 12 years old. The anterior part of the cranial base (SN length and SNBa angle) was identical in the two groups, but in Class II, cranial base flexure (BaSN angle) was more obtuse (P less than 0.05) and posterior cranial base angle (SBaN) was more acute (P less than 0.01). These variations co-existed in the same group with a more retruded position of the condylar neck in the face (P less than 0.01) favouring per se a post-normal relationship of the mandible to the maxilla. The increased extension of the saddle angle in Class II could not be considered here as related to an hyperdivergent facial pattern since facial divergence was unchanged in Class II. Saddle angle and divergence correlated in Class I (r = 0.40; P less than 0.01), but not in Class II.(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalometry↗
PubMed1991

Lung function and cardiac surgery.

In a series of 145 patients submitted to cardiac surgery, lung function data were correlated with the kind of heart disease, mitral or oartic or coronary stenosis; the post-operative evolution was evaluated. Patients with valvular diseases (VD) have a significant lower transfer capacity (TL) than coronary patients; mitral VD show a lower forced vital capacity (FVC) than aortic VD. All the patients present an important restrictive pattern in the early post-operative period. The long-term follow-up (greater than 6 months) objectivates the highly significant decrease of FVC and FEV1 in all categories of patients, while the total lung capacity remains low only in aortic VD. The transfer coefficient (TL/VA) improves significantly after mitral valve replacement, but it does not change in the other cases.

Adult↗
PubMed1990

Adult sphingomyelinase deficiency: report of 2 patients who initially presented with psychiatric disorders.

We studied 2 unrelated adult patients under neuroleptic treatment who met all phenotypic and biochemical criteria for Niemann-Pick disease type B. In addition, they had chronic psychiatric disorders and low blood levels of HDL cholesterol. The marked and persistent deficiency of acid sphingomyelinase and the disturbance of sphingomyelin metabolism in skin fibroblast subcultures ruled out a pure drug-induced lipidosis. The association of Niemann-Pick disease type B with psychiatric disorders and with low levels of HDL cholesterol could be a chance association of 2 diseases, a new phenotype of Niemann-Pick type B, or the revelation by the neuroleptic treatment of a subclinical inborn sphingomyelinase deficiency.

Adult↗
PubMed1990

[The search for meaning, with regard to the activity of reading].

"Searching for meaning" leads to approaching three levels. The level of the meaning is registered in an oriented space, using the elements of a code. The symbolic level is that of the relation between meaning and meant: to what extent does the subject have access to the world of meanings? This level encompasses two dimensions: one is paradigmatic, through which the subject associated the elements of the vocabulary with words from the same semantic field (the author refers to a survey carried out on 145 normal children as well as with reading problems, which brings to light a very characteristic evolution in the children with problems); the other dimension is syntagmantic: to what extent does the subject have access to the meaning of the text he is tackling? The third level is psycho-affective: what is the underlying meaning that the act of reading takes on for certain people? To what extent does the difficulty of reading take on the dimension of a symptom, with its unconscious roots? The author presents the details of two cases from which many lesions can be drawn. Steps to be taken on the therapeutic level are given at the end of the study.

Adolescent↗
PubMed1989

Urinary and faecal mutagenicity in car mechanics exposed to diesel exhaust and in unexposed office workers.

The occurrence of mutagens in the urine and faeces of a group of car mechanics (n = 8) exposed to high concentrations of diesel exhaust in their working place and of a group of office workers (n = 9) not exposed to diesel exhaust during working hours was compared. The aim of the study was to investigate whether the specific diesel exposure and/or other, more lifestyle-related, factors such as diet had any influence on the mutagenicity of excreta. Faeces were collected and pooled for a consecutive period of 48 h, urine was collected in the same period, but in 4 separate portions representing the urine produced during the day and at night on the 2 collection days. Information about food intake was collected by a 2-day dietary record method. Smoking habits and medicinal drug use were recorded as well. Air particulates were collected in and outside the garage during working hours. The mutagenicity of extracts of air particulates (methanol extracts), urine (XAD-2 and XAD-7 extracts) and faeces (acetone, ether and ether-NaOH extracts) was examined in the Ames test. The results did not suggest that exposure to diesel exhaust mutagens enhanced the incidence and/or degree of either faecal or urinary mutagenicity. Urine of 2 mechanics appeared to contain rather high levels of XAD-7 mutagens, but in view of the uneven distribution over the different collection periods any relationship with the exposure to diesel exhaust mutagens seems improbable. Degree and frequency of faecal mutagenicity was higher in office workers than in mechanics. The pattern of faecal mutagenicity was characteristic of that of faecapentaenes. Statistical analysis did not reveal any consistent relationships between urinary and faecal mutagenicity and the various dietary variables.

Air Pollutants↗
PubMed1986

Schwann cell marker defined by a monoclonal antibody (224-58) with species cross-reactivity. II. Molecular characterization of the epitope.

A monoclonal antibody (mAb) designated 224-58 (IgM-kappa) has been raised by fusion of Sp2/0-Ag14 mouse hybridoma cell line with spleen cells of a mouse immunized with human brain myelin. This mAb binds specifically to mouse, rat, and human Schwann cells membrane. Serological tests showed that mAb 224-58 reacted with total lipid extract, but not with total protein extract of human myelin. Combination of ELISA, complement fixation, and immunoautoradiographic detection on silica gel TLC allowed us to determine that mAb 224-58 reacted with sulfomonogalactolipids, namely 3'-sulfogalactosylceramide (SGC) and 3'-sulfogalactosyl 1-O-alkyl-ether 2-O-acylglycerol (seminolipid). The fine molecular structure of the epitope recognized by mAb 224-58 was established by studying the cross-reactivity of this mAb toward closely related sulfolipids and by comparing its reactivity after submitting either purified sulfolipids or total lipid extracts to various chemical and enzymatic treatments. The lipidic hapten-binding site to mAb 224-58 is dependent on (1) the sulfoester on carbon 3 of the galactose molecule, (2) the osidic bond, and (3) the carbonyl group of the fatty acid. Interestingly enough, neither the amide bond and the long-chain base nor the OH group of the fatty acid belongs to the antigenic determinant recognized by mAb 224-58.

Animals↗
PubMed1985

Fluctuations in arylsulphatase activity in the rabbit endometrium during the sexual cycle.

Histochemical and biochemical studies were performed to verify the presence of arylsulphatase A (ASA) and B (ASB) in the rabbit uterus. Fluctuations in the activity of these sulphatases during the sexual cycle were also studied. Some structural and functional properties of purified ASA were determined. The results indicate that arylsulphatases are active in the endometrium during both the estrogenic and progesteronic phases. The activity of ASA was much more intense than that of ASB; it increased during estrus and decreased during the post-ovulatory phase. ASB activity, however, decreased during estrus and increased during the post-ovulatory phase. The significance of these fluctuations is discussed in relation to the action of sexual hormones and physiological substrates of arylsulphatases.

Anestrus↗