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Biomedical subjects

J Francois

Publications and source records attributed to J Francois.

At least 19 recordsLinked to original sources
PubMed2006

Local recurrence after CO2 laser cordectomy for early glottic carcinoma.

OBJECTIVES: To point out prognosis factors of local recurrence after endoscopic cordectomies for Tis, T1a, T1b, and T2 glottic squamous cell carcinomas. STUDY DESIGN: A cohort of 110 patients treated from January 1990 to December 2000 at a single institution was retrospectively analyzed: 21 had Tis, 76 T1a, 7 T1b, and 6 T2 (mean follow-up 42 mo; range 1-160 mo). METHODS: The depth and extension of the excision were graded according to the European Laryngological Society Classification. Univariate analysis was used to review the impact on disease-free survival of factors related to the host, the tumor, and the treatment. RESULTS: According to the Kaplan-Meier method, the 5 year overall survival and the disease-free survival were 87% and 75%, respectively. The rates of cause-specific survival, ultimate local control with laser alone, and laryngeal preservation were 97%, 84%, and 90%, respectively. Univariate analysis by the log rank test revealed that vocal muscle infiltration (P = .001) and subglottic involvement (P = .02) have a significant impact on disease-free survival. Of the 22 patients with local recurrence (17 T1a, 1 T1b, and 4 T2), 9 were managed with total laryngectomy, 5 with partial laryngectomy, 4 with further laser cordectomy, 2 with radiotherapy, and 2 had no curative treatment. CONCLUSION: Transoral laser surgery for early glottic carcinoma is a valid alternative to radiotherapy and partial laryngectomy in terms of oncologic results. It offers low morbidity and excellent retreatment options in case of local failure. Careful patient selection for laser surgery is essential to secure good results.

Adult↗
PubMed2001

Interaction of Knr4 protein, a protein involved in cell wall synthesis, with tyrosine tRNA synthetase encoded by TYS1 in Saccharomyces cerevisiae.

The Knr4 protein, known to be involved in the regulation of cell wall assembly in Saccharomyces cerevisiae, strongly interacts with the tyrosine tRNA synthetase protein encoded by TYS1 as demonstrated by the genetic two-hybrid system and a biochemical pull-down experiment using GST--Tys1p fusion. Data reported here raise the possibility that this physical interaction between these proteins is required for dityrosine formation during the sporulation process. In addition, it is shown that the efficiency of spores formation was drastically reduced in diploid cells homozygous for the disruption of KNR4 or for a temperature-sensitive mutation of TYS1, although this effect could be independent of their protein interaction. Altogether, these data provide novel functions of Knr4p and Tys1p to those that were known before.

Cell Wall↗
PubMed1999

Biosynthetic pathway of citrinin in the filamentous fungus monascus ruber as revealed by 13C nuclear magnetic resonance

Carbon isotope distribution of [13C]citrinin from Monascus ruber incubated with [13C]acetate revealed that the biosynthesis of the toxin originated from a tetraketide, instead of a pentaketide as has been shown for Penicillium and Aspergillus species. The production of polyketide red pigments and citrinin by M. ruber may therefore be regulated at the level of the tetraketide branch point.

Journal Article↗
PubMed1995

Unusual transformation of the 3-hydroxy-picolinoyl residue of pristinamycin IA.

Pristinamycin IA was modified in a two-step procedure to give original derivatives possessing a tricyclic nucleus (8a, 8b, 8c) or a substituted pyrrole ring (10a, 10b) in place of the natural exocyclic 3-hydroxy-picolinoyl residue. This transformation involved firstly preparation of pyridinium betaines 5 from pristinamycin IA and secondly a 1-3 dipolar cycloaddition between 5 and N-substituted maleimides or diethyl acetylenedicarboxylate. The compounds obtained were evaluated as antibacterial agents alone and in association with pristinamycin IIA.

Alkylation↗
PubMed1988

Unusual basement layer in the midgut of gammaridean Niphargus virei Chevreux (Crustacea, Amphipoda).

The basement membrane of the midgut and posterior caeca epithelium in the gammaridean amphipod Niphargus virei Chevreux, 1896 is made of an unusual structure. This basal lamina, properly called "basal layer", shows a dense sheet formed by a system of dense hexagonal plates connected by thin filaments. Histochemical studies and enzymatic reactions lead to the conclusion that these structures are proteinaceous, without collagenous protein, and embedded in a neutral polysaccharide matrix. The possible mechanical significance of these mesenteric structures is discussed.

Animals↗
PubMed1985

Phosphate dependency of phosphofructokinase 2.

Experiments performed at micromolar concentrations of inorganic phosphate support the conclusion that liver phosphofructokinase 2 would be completely inactive in the absence of inorganic phosphate or arsenate. The concentration of inorganic phosphate that allowed half-maximal activity decreased with increasing pH, being approximately 0.11 mM at pH 6.5 and 0.05 mM at pH 8. The effect of phosphate was to increase V and to decrease Km for fructose 6-phosphate, without affecting Km for ATP. Citrate and P-enolpyruvate inhibited the enzyme non-competitively with fructose 6-phosphate and independently of the concentration of inorganic phosphate. Phosphorylation of the enzyme by the catalytic subunit of cyclic-AMP-dependent protein kinase did not markedly modify the phosphate requirement and its effect of inactivating phosphofructokinase 2 could not be counteracted by excess phosphate. A nearly complete phosphate dependency was also observed with phosphofructokinase 2 purified from Saccharomyces cerevisiae or from spinach leaves. By contrast, the fructose 2,6-bisphosphatase activity of the liver bifunctional enzyme was not dependent on the presence of inorganic phosphate. Phosphate increased this activity about threefold when measured in the absence of added fructose 6-phosphate and a half-maximal effect was reached at approximately 0.5 mM phosphate. Like glycerol phosphate, phosphate counteracted the inhibition of fructose 2,6-bisphosphatase by fructose 6-phosphate, but a much higher concentration of phosphate than of glycerol phosphate was required to reach this effect.

Adenosine Monophosphate↗
PubMed1985

[Biochemical and biophysical characterization of collagen in Tenebrio molitor L. (Coleoptera, Tenebrionidae)].

The collagen from the mesenteric sheath of the tenebrionid insect Tenebrio molitor was extracted by limited pepsin digestion and purified. This collagen was characterized using CM-cellulose chromatography, sodium-dodecylsulfate disc-gel electrophoresis and aminoacid analysis. This molecule was found to be assembled from three identical alpha chains and could be represented by the formula (alpha) 3. The amino acid composition is characteristic of collagen (one-third glycine, high iminoacid content), with high content of hydroxylysine and low content of alanine. Cyanogen bromide digests of these chains indicated that they are not related to any of the known invertebrate or vertebrate chains of interstitial collagens. The molecular weight (M = 280000D) and length (290 nm) were typical, and the banding patterns of the segment-long-spacing crystallites (SLS) and of the reconstitued fibrils were very similar to type I collagen. The denaturation temperature (Td) was 30.7 degrees C and correlated with the total pyrrolidine content as observed in other collagens (von Hippel & Wong's relation). It was concluded that the collagen from this insect showed the classical biochemical and biophysical features of other invertebrate interstitial "primitive" collagens.

Amino Acids↗
PubMed1980

Cockroach collagen: isolation, biochemical and biophysical characterization.

Collagen fibrils from the mesenteric connective sheath of the adult cockroach Periplaneta americana were extracted by enzymatic digestion with pepsin and were purified. Chromatographic studies and sodium dodecylsulfate electrophoresis revealed the presence of a single chain. It was demonstrated that the structure of this collagen could be represented by the formula (alpha)3. The amino acid composition is typical of collagens (one-third glycine, and a high imino acid content) and similar to that of type II. The carbohydrate content was high (8.8%), and the cyanogen bromide pattern was different from that of known collagens. The chains were linked by the stable intermolecular bond dihydroxylysinonorleucine. The banding patterns of the segment-long-spacing crystallites and of the reconstituted fibrils were similar to type I collagen. The molecular weight (Mr 280,000) and length (285 nm) were typical, but the denaturation temperature was high (38.5 degrees C). It was concluded that cockroach mesenteric collagen showed the characteristic features of invertebrate mesodermal collagens, except that of the thermal stability of the triple-helical structure.

Amino Acids↗
PubMed1979

Late results of congenital cataract surgery.

Generally speaking, it can be said, when considering all operated bilateral congenital cataracts, that a visual acuity of over 20/100 is found in approximately 50% of patients. In this study, 230 eyes were followed; of these 100 (43%) had an acuity of 20/60 or better and 130 (57%) had 20/100 or less. In conclusion the functional prognosis is better for incomplete cataracts than for total congenital cataracts. The main reason for this is the fact that total cataracts are often associated with cerebroretinal lesions or anomalies. The patient's age at operation and the surgical technique chosen are secondary factors. When considered from the standpoint of visual acuity, the results of congenital cataract surgery are discouraging, at least in the eyes with complete cataract. The visual prognosis could be better for total congenital cataracts if we operate on them at birth or immediately after birth.

Adult↗
PubMed1978

[Myasthenia syndrome after peroral treatment with penicillamine].

A 59-year-old woman has been treated for 5 months with penicillamine for a rheumatoid arthritis and developed a myasthenia syndrome with ptosis, diplopia, dysphagia and asthenia. This myasthenia was slowly cured after suppression of the penicillamine and administration of Mestinon, so that after 3 months, the anticholinesterase medication could be stopped.

Arthritis, Rheumatoid↗
PubMed1978

Bietti's crystalline fundus dystrophy.

Two cases of Bietti's crystalline fundus dystrophy are presented. The crystals in the posterior pole are associated with a diffuse tapetoretinal degeneration. The functional symptoms are less severe than in pigmentary retinopathy.

Adult↗