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Biomedical subjects

C Richaud

Publications and source records attributed to C Richaud.

At least 55 records · Page 3Linked to original sources
PubMed1985

[The vena cava in surgery of renal cancer in the adult].

In a series of 171 radical nephrectomies performed by the authors, 10 patients presented vena cava extension (5.8%). The extension was infrahepatic (stage C) in 6 cases, retrohepatic (stage B) in 1 case and involved the right auricle (stage A) in 2 cases, while the upper limit of the thrombus could not be defined in the remaining case. All patients were operated upon. There was one post-operative death (stage B), while the other patients had an uncomplicated post-operative course, despite the need for open-heart surgery in two cases. Seven patients died from metastatic after an interval of 2 and 4 years. The prognosis is therefore reserved, but seems to be better than in the case of lymph node metastases, justifying an aggressive surgical approach.

Humans↗
PubMed1984

Regulation of expression and nucleotide sequence of the Escherichia coli dapD gene.

Regulation of the Escherichia coli dapD gene involved in diaminopimelate and lysine biosynthesis was unknown as no convenient enzymatic assay was available until recently. This gene was cloned into pBR322 from a lambda transducing phage; its complete nucleotide sequence was established. This sequence shows that the dapD gene is composed of a single cistron encoding a 274-amino acid polypeptide, Mr 30,040. Enzymatic activity measurements show that this gene encodes the tetrahydrodipicolinate N-succinyltransferase which catalyzes the third step of the specific lysine-diaminopimelate pathway. The transcriptional start of the dapD gene was localized; the identified promoter signals are weak compared to those from the E. coli promoter consensus sequence. The dapD gene-coding sequence is followed by a typical rho-independent transcriptional termination sequence. A study using an operon fusion constructed in vitro between the dapD promoter and the galK structural gene indicated that dapD gene expression is repressed by lysine; no attenuation-like sequence can be found to account for this regulation. At the present time, out of the 9 genes involved in diaminopimelate and lysine biosynthesis, 6 are known to be lysine regulated.

Acyltransferases↗
PubMed1984

Nucleotide sequence and expression of the Escherichia coli dapB gene.

The Escherichia coli dapB gene encodes dihydrodipicolinate reductase. This enzyme is part of the diaminopimelate-lysine pathway, and its synthesis is repressed by lysine. The dapB gene was cloned into pBR322 from a transducing lambda bacteriophage, its complete nucleotide sequence established, and the transcriptional start localized. The DNA sequence predicts that the dapB gene codes for a 273-amino acid polypeptide, Mr 28,798. No attenuation-type sequence can be found between the mRNA start and the coding sequence. The dapB promoter signals appear to be weak as compared to RNA polymerase consensus sequences. Nevertheless an efficient in vivo synthesis of beta-galactosidase was obtained when the lac operon was inserted in vitro in the dapB gene, downstream of the dapB regulatory signals. Further studies were performed on an in-frame gene fusion constructed in vitro between the dapB and the lacZ genes. They indicated that repression by lysine is exerted on a DNA region restricted to a 153-base pair fragment with only 102 nontranscribed nucleotides. Finally, dapB gene expression showed a gene dosage effect which suggests that it is not controlled by an element present in limiting amounts in the cell.

Amino Acid Sequence↗
PubMed1984

[Tumors of the upper urinary tract. Analysis of a series of 85 cases].

Case-reports of 85 patients with upper urinary tract tumors were reviewed. Mainly affected were males (87% of cases), particularly over 60 years of age, the principal presenting sign being hematuria. Other signs such as renal colic, lumbago or infections were observed more rarely. The renal pelvis was affected in 52 of the 85 patients (two of these were bilateral), multiple tumor foci being present in only 6 cases. Most tumors were epitheliomas (62 papillary and 13 non-papillary), with 52 of these at the superficial stage (0 or A), 21 at stage B 1 and 5 at stage B II or C. Based on Broders' classification, 48 were grade II and 16 grade III tumors. Prognosis was routinely poor in 5 patients with a stage B or C tumor and lymph node extension. Diagnosis is by intravenous urography, although retrograde ureteropyelography has its place, with increasing interest being given to ultrasound and computed tomography examinations combined with routine cystoscopy. If no particular contraindications exist, the preferred treatment is a total one-stage nephro-ureterectomy without curettage (52 cases), although curettage was performed at the same time in 9 other patients. Conservative surgery has only a limited application: 6 patients had segmental resections of the ureter and 2 patients underwent tumorectomy. Postoperative mortality was particularly loco: 4 patients (4,7%), mainly from vascular or respiratory diseases. (4,7%), mainly from vascular or respiratory diseases. Bone (5 cases), pulmonary (3 cases) and medullary (1 case) metastases represented the main cause of death during the year following surgery, all these patients having infiltrating tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Cystic form of kidney cancer. Apropos of a case].

The authors report a case of cystic form of carcinoma of the kidney in a patient who also had a bladder tumour which could have explained the presenting symptom of haematuria. It was the discordance between echotomography and CT scan findings which led the authors to explore the patient surgically. A reassuring result of a frozen section biopsy led to partial nephrectomy even though the cystic mass had thick walls and serosanguinous contents. The actual diagnosis was corrected within 24 hours by the histopathologists who reported a clear cell renal carcinoma. The authors performed an extended nephrectomy which revealed the presence of some malignant cells in the remaining renal fragment. They take this opportunity to review the general problem of the association of carcinoma of the kidney and renal cyst. This case shows how hazardous may be the answer given from frozen section biopsy of a cystic mass in the kidney and how dangerous it is to perform a partial nephrectomy which may leave tumour tissue in place.

Carcinoma, Renal Cell↗
PubMed1983

Regulatory pattern of the Escherichia coli lysA gene: expression of chromosomal lysA-lacZ fusions.

The regulation of lysA which encodes the last enzyme for lysine biosynthesis in Escherichia coli, diaminopimelic acid-decarboxylase, was studied by using lysA-lacZ fusions. Our results indicate an absolute requirement for the LysR product for its activation, LysR protein present in a limiting amount which can be titrated by a multicopy plasmid carrying its target site and a negative regulatory role for the LysA protein itself which decreases lysA-lacZ expression 30-fold.

Bacterial Proteins↗
PubMed1982

[Various methods of spread of bladder tumours (author's transl)].

The authors undertake a complete review of the literature concerning the various methods of spread of bladder tumours. They successively consider spread through the thickness of the bladder wall, surface extension, direct implantation of exfoliated cells, lymphatic spread, and venous dissemination both in the bladder wall as well as to the viscera by metastases. It is difficult to give a brief analysis of such an exhaustive review. However, a number of facts are worthy of emphasis: --the frequency of invasion of the seminal vesicles and the prostate; --the reliability of combined clinical, radiological and endoscopic findings, which may be used to differentiate deep tumours and superficial tumours in more than 80% of cases; --the importance of methods which await development, such as the scanner and, above all, ultrasound techniques; --the importance of study of the vesical mucosa at a distance from the tumour itself, both by fluorescent cystoscopic methods, as well as by distant biopsies (30 to 50% of premalignant cell changes found in cystoscopically normal zones); --the frequency if invasion of the terminal portions of the ureters (10% on average) and of the urethra (12 to 15%); --the prognostic gravity of tumour emboli in the intraparietal lymph vessels, the presence of which reduces the chances of cure at 5 years by two thirds; --the usual limitation of the first lymph node spread to the external iliac and hypogastric vessels with the exception of tumours of the bladder neck, where the first lymph node spread occurs to the aortic bifurcation; --the gravity of the presence of emboli in the parietal veins which reduces chances of survival at 5 years by half; --finally, the recently recognized frequency of secondary bone tumours; --and the supposed frequency of infraclinical metastases which would be a considerable argument in favour of complementary chemotherapy in therapeutic protocol for carcinomas of the bladder.

Humans↗
PubMed1982

[Caval extension of renal cancer. Surgical problems].

The authors report on a case of renal neoplasm with associated thrombosis of the vena cava extending to the right auricle. The authors undertook, right away, by way of a median sternotomy and under extracorporeal circulation, the ablation of the intra-cardiac thrombus, and also the removal of the remainder of thrombus in the inferior vena cava. This having been achieved without complications, they performed excision of the right kidney as well as a cavectomy, thus effecting ablation of the tumour while preserving the venous drainage above the liver and the left renal vein. A review of the literature confirms that exeresis of this type of tumour is logical in the absence of metastasis or lymphatic invasion. They stress, above all, the importance of firstly effecting exeresis of the intra-cardiac thrombus under the facility of extracorporeal circulation. This ensures the least risk to the patient, for surgery of this kind.

Adenocarcinoma↗
PubMed1981

Construction of hybrid plasmids containing the lysA gene of Escherichia coli: studies of expression in Escherichia coli and Saccharomyces cerevisiae.

The lysA gene of Escherichia coli has been cloned from a lambda transducing phage on various plasmids, present in different copy numbers in bacterial cells. Synthesis of the product of this gene, diaminopimelate (DAP)-decarboxylase, and its regulation have been studied. Expression does not follow a simple gene dosage effect, maximal expression already being obtained with a six-copy plasmid. This result suggests that either a positive or an autogenous regulatory mechanism is involved. We also used one of the hybrid plasmids to look for expression of the bacterial lysA gene in Saccharomyces cerevisiae. The results indicate that the product of the E. coli gene is not actively translated in yeast.

Bacterial Proteins↗
PubMed1981

[Results of endoscopic urethrotomy (author's transl)].

The authors report the results of 63 internal urethrotomies for urethral stenosis performed during a four year period. The essential sites were perineal and the most frequent aetiology iatrogenic, particularly after prostatectomy. Overall, the authors obtained 18 satisfactory results, 2 severe complications, 24 failures and 17 patients are too recent to assess or were lost from sight. A second endoscopic urethrotomy gave only very little chance of a definitive recovery. Although the results were not constantly excellent, the series studied by the authors shows that endoscopic internal urethrotomy offers the possibility by a simple technique of obtaining a certain number of durable successes whilst not interfering with the subsequent performance of other types of urethroplasty. Finally, in a certain number of cases endoscopic internal urethrotomy facilitates subsequent dilatations.

Endoscopy↗
PubMed1980

The relA locus and the regulation of lysine biosynthesis in Escherichia coli.

The allelic state of relA influences the phenotype of Escherichia coli strains carrying the lysA22 mutation:lysA22 relA strains are Lys- where lysA22 relA+ strains grow (slowly) in the absence of lysine. This physiological effect has been related to an effect of the expression of the relA locus on the regulation of lysine biosynthesis. The fully derepressed levels of some lysine enzymes (aspartokinase III, aspartic semialdehyde dehydrogenase, didhydrodipicolinate reductase) are observed under lysine limitation only in rel+ strains. And the induction of DAP-decarboxylase by DAP is much higher in rel+ than in rel- strains when an amino acid limitation of growth is also realised. These results are in agreement with the hypothesis of Stephens et al. (1975) on a possible role of the stringent regulation as a general signal for amino acid deficiency.

Aspartate Kinase↗