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P Richaud

Publications and source records attributed to P Richaud.

At least 55 records · Page 3Linked to original sources
PubMed1994

Structure and function of the tetraheme cytochrome associated to the reaction center of Roseobacter denitrificans.

We have characterized the tetrahemic RC bound cytochrome isolated from the quasi-photosynthetic bacterium Roseobacter denitrificans in terms of absorption spectrum, redox property and orientation with respect to the membrane plane. The heme, designated H1, which possesses the highest redox midpoint potential (+290 mV), absorbs at 555 nm. Its plane makes an angle of 40 degrees with the membrane plane. The second high potential heme, H2 (+240 mV), peaks at 554 nm and makes a tilt of 55 degrees with the membrane. The two low potential hemes, L1 and L2, present a similar and rather high redox midpoint potential (+90 mV). They absorb at 553 nm and 550 nm. One of these hemes is oriented at 40 degrees while the other makes an angle of 90 degrees with the membrane plane. The soluble cytochrome c551 completes the cyclic electron transfer between the RC and the bc1 complex. Both the oxidation and the re-reduction of cytochrome c551 are diffusible processes. Under semi-aerobic conditions, one of the low potential hemes is photo-oxidized under illumination but only extremely slowly re-reduced. This explains the requirement of high aerobic conditions for growth of Roseobacter denitrificans cells in the light.

Bacteria↗
PubMed1993

Ethmoidal cancers: a retrospective study of 22 cases.

From April 1978 to June 1990, 22 patients with ethmoidal cancer were treated at Fondation Bergonié by a combination of surgery and radiation therapy. The mean age was 59.6 years (range 34-79 years) and the sex ratio is 2.7 (16 males/6 females). Histologic types were: adenocarcinoma, 13 cases; squamous carcinoma, 4 cases; undifferentiated carcinoma, 3 cases and esthesioneuroblastoma, 2 cases. Exposure to wood dust was encountered in 11 patients, especially in cases of adenocarcinoma: 10/13 (77%). Staging according to the classification of the University of Florida was: Stage I, 10 patients; Stage II, 5 patients and Stage III, 7 patients. Resection was considered as complete in 16 cases and only one orbital exenteration was performed. The postoperative radiation therapy delivered a mean given dose of 55.7 Gy (range 50-70 Gy) expressed to the hot spot using a technique adapted to tumor location and extension. Complete remission was achieved in 20 cases. Median follow-up is 28 months. The 5-year overall and disease-free survival are 44% and 38%, respectively. Analysis of recurrences according to staging gives: 5/10 Stage I, 2/5 Stage II and 5/7 Stage III. Recurrence is pejorative since death occurs in all cases within an average of 6 months following salvage treatment, except for three patients still alive within less than 6 months and in second remission. Prognosis of ethmoidal cancer depends on staging and local control.

Adenocarcinoma↗
PubMed1993

Organization of the genes necessary for hydrogenase expression in Rhodobacter capsulatus. Sequence analysis and identification of two hyp regulatory mutants.

A 25 kbp DNA fragment from the chromosome of Rhodobacter capsulatus B10 carrying hydrogenase (hup) determinants was completely sequenced. Coding regions corresponding to 20 open reading frames were identified. The R. capsulatus hydrogenase-specific gene (hup and hyp) products bear significant structural identity to hydrogenase gene products from Escherichia coli (13), from Rhizobium leguminosarum (16), from Azotobacter vinelandii (10) and from Alcaligenes eutrophus (11). The sequential arrangement of the R. capsulatus genes is: hupR2-hupU-hypF-hupS-hupL-hupM-hu pD-hupF-hupG-hupH-hupJ-hupK-hypA- hypB-hupR1- hypC-hypD-hypE-ORF19-ORF20, all contiguous and transcribed from the same DNA strand. The last two potential genes do not encode products that are related to identified hydrogenase-specific gene products in other species. The sequence of the 12 R. capsulatus genes underlined above is presented. The mutation site in two of the Hup- mutants used in this study, RS13 and RCC12, was identified in the hypF gene (deletion of one G) and in the hypD gene (deletion of 54 bp), respectively. The hypF gene product shares 45% identity with the product of hydA from E. coli and the product of hypF from R. leguminosarum. Those products present at their N-terminus a Cys arrangement typical of zinc-finger proteins. The G deletion in the C-terminal region of hypF in the RS13 mutant prevented the expression of a hupS::lacZ translational fusion from being stimulated by H2 as it is observed in the wild-type strain B10. It is inferred that the HypF protein is a factor involved in H2 stimulation of hydrogenase expression.

Amino Acid Sequence↗
PubMed1993

Sequence analysis and interposon mutagenesis of the hupT gene, which encodes a sensor protein involved in repression of hydrogenase synthesis in Rhodobacter capsulatus.

The hupT gene, which represses hydrogenase gene expression in the purple photosynthetic bacterium Rhodobacter capsulatus, has been identified and sequenced. The nucleotide sequence of hupT and of the contiguous downstream open reading frame, hupU, is reported. The HupT protein of 456 amino acids (48,414 Da) has sequence similarity with the FixL, DctB, NtrB, and ArcB proteins and is predicted to be a soluble sensor kinase. Insertional inactivation of the hupT gene led to deregulation of transcriptional control, so that the hydrogenase structural operon hupSLC became overexpressed in cells grown anaerobically or aerobically. The HupT- mutants were complemented in trans by a plasmid containing an intact copy of the hupT gene. The hupU open reading frame, capable of encoding a protein of 84,879 Da, shared identity with [NiFe]hydrogenase subunits; the strongest similarity was observed with the periplasmic hydrogenase of Desulfovibrio baculatus.

Amino Acid Sequence↗
PubMed1993

[ORL cancers in patients under the age of 45 years. Epidemiology, prognosis and treatment: apropos of 106 cases].

106 ENT localized carcinomas (97 men and 9 women) in adults under 45 years old are reviewed. The mean age was 40.0 years old and most suffered from an alcoholic and/or nicotine addiction. 89.6% expressed an epidermoid carcinoma and buccal cavity and larynx lesions represented the most frequent locations, followed by the pharynx. Overall survival does not differ from that of an older population but some locations seem to have a very poor prognosis: mobile tongue, vallecula, piriform sinus and amygdala. On the other hand, the laryngeal locations confirm their favorable prognosis.

Adult↗
PubMed1992

Intra-operative electron beam radiotherapy and abdomino-pelvic surgery for cancer: influence on immunological parameters.

Evolution of some immunological parameters was observed during the first month in 20 patients with different abdomino-pelvic cancers who underwent surgery with intra-operative radiation therapy (IORT) (mean dose of 19.44 Gy, range 15, 25). Observed parameters before (DO-) and after procedure (DO+), on seventh (D7) and fourteenth (D14) days and fifth week (D30) were: lymphocyte count, lymphocyte subsets (CD19, CD3, CD4, CD8, CD56), natural killer (NK) activity, immunoglobulins, C3 and C4b fractions of complement, soluble receptor for interleukin 2 (sIL2-R). Results showed a decrease of circulating lymphocytes (DO-: 1189 +/- 168 cells/mm3; D7: 889 +/- 91; P = 0.011), of absolute number of CD3 lymphocytes (DO-: 785 +/- 114 cells/mm3; D7: 563 +/- 86; P = 0.025), of CD4 lymphocytes (DO-: 441 +/- 70 cells/mm3; DO+: 299 +/- 43; P = 0.013) and of CD8 lymphocytes (DO-:361 +/- 50 cells/mm3, D7:250 +/- 44; P = 0.006). All values returned towards preoperative levels by D30. Absolute number of NK cells was unchanged but NK activity was significantly diminished (effector target ratio 5:1 DO-:33 +/- 5%; DO+:44 +/- 7%; D7:18 +/- 3%; D14:21 +/- 4%; D30:25 +/- 4%). sIL2-R was significantly enhanced from D7 to D30. All these impairments are moderate and these observations provide some evidence of satisfactory tolerance to IORT for abdomino-pelvic cancers during the immediate postoperative period.

Abdominal Neoplasms↗
PubMed1992

Regimen-related toxicity in patients undergoing BMT with total body irradiation using a sweeping beam technique.

In our institution, total body irradiation (TBI) is performed by means of a sweeping beam technique. Toxicity of the procedure was evaluated according to the only grading system designed for high dose chemoradiotherapy. One hundred patients undergoing TBI and conditioned with a standard cyclophosphamide regimen before BMT were evaluated. Regimen-related toxicity was graded according to the Seattle transplantation toxicity system, from 0 to IV (fatal toxicity), in eight organs on days 0, 7, 14, 28 and 100 for lungs. Eighteen patients did not develop any toxicity. Grades III, IV toxicities were uncommon (9%) and were not influenced by dose of TBI, GVHD prophylaxis, disease status and allogenicity although no grade IV toxicity was observed among autologous marrow recipients. However, grade II toxicity was more common in patients receiving allogeneic vs autologous grafts (p < 0.01) because of increased mucosal (p = 0.002) and liver (p = 0.12) toxicities. Renal toxicity was unevaluable. When cumulative toxicity was equal or higher than 4, day 100 survival was worse (p = 0.05). These data confirm the safety of our TBI procedure and the validity of the grading system except for renal toxicity. We suggest that a more aggressive conditioning regimen may be tolerated by patients receiving autologous grafts.

Adolescent↗
PubMed1991

A mutation in a Rhodobacter capsulatus gene encoding an integration host factor-like protein impairs in vivo hydrogenase expression.

A gene capable of encoding a protein sharing 45% identical amino acids with the alpha subunit of the integration host factor (IHF) of Escherichia coli was isolated from the photosynthetic bacterium Rhodobacter capsulatus strain B10 by complementation of a hydrogenase-deficient (Hup-) mutant, IR4. A DNA fragment of 274 base pairs containing an IHF binding consensus sequence, isolated from the promoter region of the hydrogenase structural genes (hupSL), was shown by gel retardation assays to bind the IHF protein from E. coli. The product of the R. capsulatus gene was shown to bind specifically to the 274-base-pair DNA fragment from the hupSL promoter. By analogy to the E. coli himA gene, which encodes the alpha subunit of IHF, the gene complementing the IR4 mutant was named himA of R. capsulatus. The wild-type himA gene, cloned in plasmid pBO2, was introduced into the IR4 strain and shown to restore, in trans, hydrogenase activity and autotrophic growth in the mutant. In IR4, a C----T transition mutation had replaced Arg-8 by Cys-8. Gel mobility shifts of the 274-base-pair DNA fragment, not observed with the himA gene product of IR4, were restored with extracts from IR4(pBO2) cells, containing the himA gene on the recombinant plasmid pBO2.

Amino Acid Sequence↗
PubMed1991

Low-grade follicular lymphomas: analysis of prognosis in a series of 281 patients.

From 1963 to 1988, 281 patients with newly diagnosed follicular lymphomas were treated and followed at the Foundation Bergonié. Distribution of stages was: 72 I, 61 II, 83 III and 65 IV. Within stage III, two subgroups were retrospectively defined: stages III1 (32 cases) included patients with less than 8 involved sites, only 1 or 2 above diaphragm, and no spleen or mediastinal enlargement. Stage III2 (51 cases) included the remaining stage III cases. Median follow-up was 9 years. Complete remission (CR) rate was 82%. 10-year overall survival (OS) and time to treatment failure (TTF) rates were, respectively 38% and 29.5%. 10-year time to relapse (TTR) rate was 36%. Statistical analyses showed concordant results with two main prognostic factors: age (less than 60/greater than 60) and stage (I to III1/III2 and IV). Age was the most important factor for OS analysis and stage for CR and TTR analysis. This leads to only three prognostic groups with different outcome. The first includes younger patients (less than 60 years) with limited stages (less than or equal to III1); the second, patients either older than 60 or with advanced stages; the last, elderly patients with advanced stages. CR rates of these three groups were, respectively 97%, 75% and 57%. 10-year OS were, respectively 73.5%, 27% and 0%; 10-year TTR were 54%, 22% and 0%. These results have lead to data which are easy to handle and which can help to establish a rationale for further prospective trials.

Adult↗
PubMed1991

[Preparation of leukocyte-depleted human platelet concentrates by centrifugation and filtration of a pool of sterilely connected buffy-coats].

We describe a new method for the preparation of standardised therapeutic doses of leukocyte depleted platelets. The first step is to remove the buffy-coat from whole blood units drawn on triple Siamese ACD/SAGM bags (Maco-Pharma) by means of a Compomat (NPBI). The second step is to connect (SCD Haemonetics) six buffy-coats and one plasma to a special kit (Maco-Pharma) including a PALL PL 100 filter; after centrifugation, the supernatant platelet concentrate is extracted, filtered and recovered in a 2 litre TOTM PVC bag. The volume, the number of platelets and leukocytes of these pools are measured. A comparison of these parameters is made with therapeutic doses prepared in the same way without filtration. Besides, pH measurements up to the 6th day of storage and bacteriological checks are carried out. The results show: no platelet loss related to filtration; a synergy between the preparation process out of buffy-coats and the filtration: so each dose contains less than 10(6) leukocytes; a good pH level allowing the storage for five days as it is associated to the bacteriological safety of the functionally closed system. This technique makes it possible to transfuse only leukocyte depleted platelet concentrates. In addition, it offers new prospects for standardisation and quality improvement.

Blood Transfusion↗
PubMed1991

Identification and sequence analysis of the hupR1 gene, which encodes a response regulator of the NtrC family required for hydrogenase expression in Rhodobacter capsulatus.

The hupR1 gene from Rhodobacter capsulatus was cloned and sequenced. It can encode a protein of 53,843 Da which shares significant similarity with several transcriptional regulators and activates transcription of the structural hupSL genes of [NiFe]hydrogenase, as shown by the use of a translational fusion of lacZ with the hupSL promoter. A Hup- mutant having a point mutation in the hupR1 gene is described.

Amino Acid Sequence↗
PubMed1991

[Role of radiotherapy in cancer of the ethmoid. Retrospective study of a series of 24 cases].

From april 1978 to december 1988, 24 patients were treated were by radiotherapy at the Bergonié Foundation cases were for ethmoidal cancer cases. Twenty two for initial treatment and two refermed for local recurrence. The mean age was 51.4 years and the sex ratio was 5.2 (21 men/4 women). Histologically there were 15 adenocarcinomas, 3 squamous carcinomas, 4 undifferentiated carcinomas and 2 esthesioneuroblastomas. According to the classification of the University of Florida, they were retrospectively classified as stage I = 9 pts, stage II = 5 and stage III = 10. Twenty one patients had postoperative radiotherapy and 3 had exclusive radiotherapy. The average dose was 55.3 Gy. Local control was obtained in 12 pts. Seven patients have recurred locally (within an average period of 12 months) and 5 patients showed progression of disease after treatment. The overall actuarial survival and the disease free survival at 5 years were respectively 50% and 53%. The actuarial survival by stage at 2 years and 5 years was: stage I (88% and 61%), stage II (100% and 50%), stage III (0%). The prognosis of ethmoidal cancer is strictly correlated to local control. For this reason, radiotherapy (with or without surgery) remains important in the treatment of this disease.

Adult↗
PubMed1990

Cloning and sequencing the genes encoding uptake-hydrogenase subunits of Rhodocyclus gelatinosus.

Rhodocyclus gelatinosus grew photosynthetically in the light and consumed H2 at a rate of about 665 nmol/min per mg protein. The uptake-hydrogenase (H2ase) was found to be membrane bound and insensitive to inhibition by CO. The structural genes of R. gelatinosus uptake-H2ase were isolated from a 40 kb cosmid gene library of R. gelatinosus DNA by hybridization with the structural genes of uptake-H2ase of Bradyrhizobium japonicum and Rhodobacter capsulatus. The R. gelatinosus genes were localized on two overlapping DNA restriction fragments subcloned into pUC18. Two open reading frames (ORF1 and ORF2) were observed. ORF1 contained 1080 nucleotides and encoded a 39.4 kDa protein. ORF2 had 1854 nucleotides and encoded a 68.5 kDa protein. Amino acid sequence analysis suggested that ORF1 and ORF2 corresponded to the small (HupS) and large (HupL) subunits, respectively, of R. gelatinosus uptake-H2ase. ORF1 was approximately 80% homologous with the small, and ORF2 was maximally 68% homologous with the large subunit of typical membrane-bound uptake-H2ases.

Amino Acid Sequence↗
PubMed1990

Molecular biology studies of the uptake hydrogenase of Rhodobacter capsulatus and Rhodocyclus gelatinosus.

In the photosynthetic bacteria, as in other N2-fixing bacteria, two main enzymes are involved in H2 metabolism: nitrogenase, which catalyses the photoproduction of H2, and a membrane-bound (NiFe) hydrogenase, which functions as an H2-uptake enzyme. The structural genes for Rhodobacter capsulatus and Rhodocyclus gelatinosus uptake hydrogenases were isolated and sequenced. They present the same organization, with the gene encoding the small subunit (hupS) (molecular masses 34.2 and 34.6 kDa, respectively) preceding the gene encoding the large one (hupL) (molecular masses 65.8 and 68.5 kDa, respectively). The two hupSL genes apparently belong to the same operon. The deduced protein sequences of the small and of the large subunits share nearly 80% and maximally 70% identity, respectively, with their counterparts in uptake hydrogenases found in N2-fixing bacteria. However, unlike in Bradyrhizobium japonicum, R. gelatinosus or Azotobacter chroococcum, another open reading frame (ORFX) was found downstream and contiguous to the R. capsulatus hupSL whose transcription seemed to depend on the same hup promoter as hupSL. ORFX contained 786 nucleotides capable of encoding a hydrophobic polypeptide of 262 amino acids (30.2 kDa).

Amino Acid Sequence↗
PubMed1990

[Radiotherapy of carcinoma of the nasopharynx].

Cancer of the cavum is a rare condition in France. These tumors have, however, a poor prognosis and in general occur in young subjects. While radiotherapy would appear to be the best mean of ensuring local control, life expectancy depends solely on distant metastases. Analysis of a series of 58 cases treated at the Fondation Bergonié from 1975 to 1985 demonstrated a 30% five year survival rate. Among the 25 cases of recurrence, 1 was exclusively local and 6 were loco-regional (T and N), while 18 patients presented metastatic progression, either exclusively, or with local or lymph node failure. The prognostic factors found in this series were: age, extension beyond the cavum, the dose of radiotherapy. Results in the literature in terms of survival remain poor, especially in advanced stages and the future perspectives for better control of this disease remain early diagnosis and other forms of therapy such as combined chemotherapy and radiotherapy.

Adolescent↗
PubMed1990

[Cancer of the lips. Results of the treatment of 299 patients].

From 1970 to 1985, 299 patients with carcinoma of the lip were entirely managed at the Bergonié Foundation. Interstitial radiotherapy was most commonly used. It resulted in a successful local control in 96% of cases (238/248), while cosmetic and functional results seemed better than those of surgery. However, surgery seemed more performant for in situ carcinomas, late aggressive T3 carcinomas, local recurrences, as for T4 lesions associated with other techniques. After reviewing the case history of patients with local recurrences, we found technical faults in one half of those managed by interstitial radiotherapy. Local control rates after surgical salvage of recurrences was 99%. Treatment of neck nodes was not discussed in this publication.

Adult↗