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Biomedical subjects

B Noel

Publications and source records attributed to B Noel.

At least 19 recordsLinked to original sources
PubMed2000

Qualitative and quantitative study of human osteoblast adhesion on materials with various surface roughnesses.

We quantitatively evaluated the adhesion of human osteoblasts on orthopedic metallic substrates (Ti6Al4V alloy) with various surface roughnesses at several times after inoculation and studied its correlation with qualitative changes in the expression of adhesion proteins and with parameters extensively describing the surface topographies. Cells were orientated in a parallel order on polished surfaces. This orientation was not affected by residual grooves after polishing. On sandblasted surfaces the cells never attained confluence and had a stellate shape, and the cell layer had no particular organization. Extracellular matrix (fibronectin, type I collagen, osteopontin) and cytoskeletal protein (actin, vinculin) orientation reflected the cell layer organization. In our experiment human osteoblasts expressed alpha3beta1 integrin but not alpha2beta1 integrin. In addition to currently analyzed roughness magnitude parameters, we calculated roughness organization parameters (fractal dimension parameters) of the substrates. We observed lower adhesion and proliferation on less organized surfaces (i.e., sandblasted ones). The significant statistical correlation observed between fractal dimension parameters (describing surface roughness organization) and cell parameters adds a new concept to the studies of substratum roughness influence on cell behavior. An attempt at modelization of the cell-surface interaction was made that includes the influence of fractal dimensions parameters.

Alloys↗
PubMed1997

Proliferation and differentiation of human trabecular osteoblastic cells on hydroxyapatite.

In order to evaluate whether human osteoblastic cells differentiate normally on hydroxyapatite, we have compared the adhesion, proliferation, and differentiation of human trabecular (HT) osteoblastic cells on synthetic-dense hydroxyapatite and on standard plastic culture. We show here that initial HT cell attachment was 4-fold lower on hydroxyapatite than on plastic after 4 h of culture, and that normal cell attachment on hydroxyapatite was restored after 18 h of culture. HT cell proliferation was similar on the two substrates at 2-8 days of culture, but was lower on hydroxyapatite compared to plastic after 15 and 28 days of culture, as evaluated by DNA synthesis or cell number. HT cells cultured on both substrates produced an abundant extracellular matrix which immunostained for Type I collagen. The levels of carboxyterminal propeptide of Type I procollagen (P1CP) in the medium were lower in HT cell cultures on hydroxyapatite than on plastic. In addition, (3H)-proline incorporation into matrix proteins and the mean thickness of matrix layers were 52% and 26% lower, respectively, on hydroxyapatite compared to plastic after 4 weeks of culture, indicating that the total collagenous matrix synthesized by HT cells was lower on hydroxyapatite. However, (3H)-proline and calcium uptake expressed per cell was higher on hydroxyapatite than on plastic. The results show that human osteoblastic cells attach, proliferate, and differentiate on dense hydroxyapatite with a sequence similar to that of plastic. However, the growth of human osteoblastic cells is lower on hydroxyapatite in long-term culture, which results in a reduced amount of extracellular matrix, although matrix production per cell may be increased.

Biocompatible Materials↗
PubMed1996

Pseudoaneurysm of the proper hepatic artery with duodenal fistula appearing as a late complication of blunt abdominal trauma.

Posttraumatic pseudoaneurysms of the hepatic artery are rare and usually occur as a complication of open abdominal trauma. Even less common is the coexisting presence of enteric fistulization. We report a patient with upper gastrointestinal hemorrhage occurring 3 years after blunt abdominal trauma resulting from a pseudoaneurysm of the proper hepatic artery with duodenal fistulization. The patient was treated successfully by ligation of the proper hepatic artery and closure of the duodenal opening.

Abdominal Injuries↗
PubMed1994

Mapping of the Down syndrome phenotype on chromosome 21 at the molecular level.

Phenotypic and molecular analysis of individuals with partial trisomy 21 can be used to determine which regions of chromosome 21 are involved in the pathogenesis of specific features of Down's Syndrome. Using dosage analysis of 27 sequences we defined, at the molecular level, the extent of the chromosome 21 duplication in ten individuals with partial trisomy 21. Phenotype-genotype correlations led to the definition of minimal regions, the duplications of which are linked to the expression of 23 clinical features of Down's Syndrome. The D21S55 region or Down's Syndrome Chromosome Region 1 (DCR1) (1/20 of the long arm), on 21q22.2-21q22.3 proximal, is involved in four cardinal features of the disease: mental retardation, growth retardation, muscular hypotonia and joint hyperlaxity, and in eight of the 18 more common morphological anomalies of the face, hands and feet. Overlapping the DCR1, the D21S55-MX1 region or DCR2 (1/10 of the long arm), spanning 21q21.2 down to the 1/4th proximal part of 21q22.3, is involved in the features defined by the DCR1 plus congenital heart defect and five additional morphological anomalies. Thus, our results indicate that duplication of a relatively small region of chromosome 21 plays a critical role in the pathogenesis of the Down's phenotype.

Chromosome Mapping↗
PubMed1993

Molecular mapping of twenty-four features of Down syndrome on chromosome 21.

To determine which regions of chromosome 21 are involved in the pathogenesis of specific features of Down syndrome, we analysed, phenotypically and molecularly, 10 patients with partial trisomy 21. Six minimal regions for 24 features were defined by genotype-phenotype correlations. Nineteen of these features could be assigned to just 2 regions: short stature, joint hyperlaxity, hypotonia, major contribution to mental retardation and 9 anomalies of the face, hand and foot to the region D21S55, or Down syndrome chromosome region (DCR), located on q22.2 or very proximal q22.3, and spanning 0.4-3 Mb; 6 facial and dermatoglyphic anomalies to the region D21S55-MX1, including the DCR and spanning a maximum of 6 Mb on q22.2 and part of q22.3. Thus, the complex phenotype that constitutes Down syndrome may in large part simply result from the overdosage of only one or a few genes within the DCR and/or region D21S55-MX1.

Adolescent↗
PubMed1993

Ovarian follicular dynamics in Suffolk ewes at different periods of the year.

Five Suffolk ewes underwent daily laparoscopy for 18 days at the onset, middle and end of the breeding season (August, November and February, respectively) and during anoestrus (May) to examine their ovaries. Ovarian follicles > or = 2 mm were measured and their relative locations reported on an ovarian map to follow the sequential development of each individual follicle. Some aspects of follicular growth (mean day of emergence and mean number of small, medium-sized and large follicles, maximum size before regression and ovulation rate) were also studied and compared. Three waves of follicular growth and atresia were observed during the oestrous cycle; two waves occurred during the luteal phase and one during the follicular phase. This cyclic pattern of growth and atresia was not influenced by the stage of the breeding season. A similar turnover of follicles occurred during anoestrus. Features of follicular growth were similar at all stages studied except for the size of the large follicles which were smaller during the two waves of the luteal phase (P < 0.05). The number of growing follicles did not vary and the mean ovulation rate was 1.2 +/- 0.4 at all stages of the breeding season.

Anestrus↗
PubMed1992

Processing and characterization of the low density lipoprotein receptor in the human colonic carcinoma cell subclone HT29-18: a potential pathway for delivering therapeutic drugs and genes.

Low density lipoprotein (LDL) processing has been investigated in the subcloned human colonic carcinoma cell line HT29-18. LDL binding at 4 degrees C was a saturable process in relation to time and LDL concentration. The Kd for LDL binding was 11 micrograms/ml. ApoE-free HDL3 or acetylated LDL did not significantly compete with 125I-LDL binding, up to 500 micrograms/ml. 125I-LDL binding was decreased by 70% in HT29-18 cells preincubated for 24 hours in culture medium containing 100 micrograms/ml unlabelled LDL. Ligand blotting studies performed on HT29-18 homogenates using colloidal gold labelled LDL indicated the presence of one autoradiographic band corresponding to an apparent molecular weight of 130 kDa, which is consistent with the previously reported molecular weight of the LDL receptor in human fibroblasts. At 37 degrees C, 125I-LDL was actively internalized by HT29-18 cells and lysosomal degradation occurred as demonstrated by the inhibitory effect of chloroquine. LDL uptake and degradation by HT29-18 cells also resulted in a marked decrease in endogenous sterol synthesis. These data demonstrate that the HT29-18 human cancerous intestinal cells are able to specifically bind and internalize LDL, and that LDL processing results in down-regulation of sterol biosynthesis. Thus, intestinal epithelial cells possess specific LDL receptors that can be exploited to accomplish drug delivery and gene transfer via the receptor-mediated endocytosis pathway.

Colonic Neoplasms↗
PubMed1992

[Electronic podometry--2-year experience: preliminary report].

The authors relate their experience with the EMED system for the dynamic assessment of plantar pressure used in clinical practice for 2 years: how the measurement device was chosen; how the examination is performed; the usefulness of this type of examination in foot surgery. They discuss the specific problems related to the application of this new diagnostic tool in clinical practice.

Biomechanical Phenomena↗
PubMed1990

Infertility in human males with autosomal translocations: meiotic study of a 14;22 Robertsonian translocation.

Pachytene analysis was undertaken in a male patient heterozygous for a 14q22q Robertsonian translocation. The relatively low rate of XY autosome association led us to examine the relationships existing between the chromosomes involved in the translocation, the rate of XY-autosome association and the degree of spermatogenic failure. Cytogenetic investigations in infertile men and the results of the meiotic studies suggest a direct correlation between the frequency of XY-autosome association at pachytene and the degree of spermatogenic failure. Whether associations arise as a consequence or cause of germ cell failure is still not certain.

Adult↗
PubMed1990

DNA amplification of HIV-1 in seropositive individuals and in seronegative at-risk individuals.

We assessed the HIV-1 status of seropositive and seronegative at-risk individuals by the polymerase chain reaction. Fifty-four out of 55 HIV-1-seropositive samples scored positive. However, HIV-1 proviral DNA was not detected in 16 seronegative homosexuals, 20 seronegative polytransfused haemophiliacs and 20 seronegative thalassaemic children, 20 individuals with isolated and persistent anti-core antibodies and 74 seronegative blood donors. These data indicate that positive HIV-1 DNA is likely to be an exceptional phenomenon in HIV-seronegative people.

Adult↗
PubMed1989

Molecular definition of de novo and genetically transmitted WAGR-associated rearrangements of 11p13.

We describe a family in whom the phenotypically normal father carries a balanced insertional translocation, ins(14;11)(q23;p12p14). This individual fathered three mentally retarded children, two with a del(11)(p13) and one with a dup(11)(p13). Two other cases of a de novo del(11)(p13) are also described. All four del(11)(p13) cases presented with WAGR, a complex syndrome associated with a predisposition to Wilms' tumor (WT), aniridia (A), genitourinary abnormalities (G), and mental retardation (R). Using an approach combining karyotype analysis, determination of the gene copy number, and RFLP studies employing five 11p13 DNA markers, we were able to define the chromosomal rearrangement involved in each case. Analysis of these WAGR deletions provides further subdivision of band p13 on chromosome 11.

Adult↗
PubMed1988

Meiotic analysis of two human reciprocal X-autosome translocations.

Two cases of human reciprocal X-autosome translocation, t(X;12) and t(X;2), are described in sterile males, along with meiotic findings. Each carrier had inherited the translocation from his mother. Both showed azoospermia and germ-cell maturation arrest at the primary spermatocyte level, with most cells being arrested at the pachytene stage. A few metaphase I (MI) divisions were found, with occasional metaphase II cells being seen in the t(X;2) carrier. MI air-dried preparations gave clear evidence of chain quadrivalent formation. In the t(X;2) heterozygote, the pairing characteristics of the quadrivalent at pachytene were also analyzed in electron microscopic spreads. Disturbance of pairing around the breakpoints characterized most quadrivalents, and there was evidence in about 20% of the cells that nonhomologous pairing had taken place between the translocated chromosomes and the normal chromosome 2. Comparisons are made with similar nonhomologous pairing configurations seen at pachytene in quadrivalents of male reciprocal X-autosome translocations of the mouse.

Adult↗
PubMed1988

Electrophysiological study of intravenous pinaverium bromide in cardiology.

Pinaverium bromide is a musculotropic spasmolytic agent which acts by inhibiting transmembrane calcium movements, an effect similar to that of verapamil. Because of this, an investigation was carried out to see if it had any electrophysiological effects in patients with various cardiac disorders. In an open study, 10 patients received 2 mg pinaverium bromide intravenously. In a double-blind study, 10 patients received 4 mg pinaverium bromide intravenously and 10 patients placebo. Patients included those with either normal or pathological basal conduction, such as bundle-branch block and 1st degree atrioventricular block. Measurements were made of electrophysiological parameters before and 10 minutes after injection. The results showed that neither of the two doses of pinaverium bromide had any effect on atrial excitability, sino-atrial conduction, node and trunk atrioventricular conduction or on intraventricular conduction. No significant difference was seen in comparison with placebo. Pinaverium bromide had no anti-arrhythmic properties in these studies. Local, cardiac and general clinical tolerability was good in all patients.

Aged↗