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Biomedical subjects

J Rigaud

Publications and source records attributed to J Rigaud.

At least 19 recordsLinked to original sources
PubMed2006

[Should double J catheter be systematically considered in renal transplantation?].

Protection of urinary anastomoses using a ureteral catheter is a frequent option in urology but such use in a systematic manner remains debated in renal transplantation. Some consider that systematic insertion of a double J sound decreases the incidence of ureteral complications (fistula and stenosis). Others who prefer a selective use in some situations with a related risk consider that the implementation of a double J catheter cannot compensate a technical defect. It is even responsible for specific complications (infections, incrustation, haemorrhages); it increases implantation costs and is useless in more than 90% of the cases. This article analyses the risks related to systematic implementation of a double J catheter in Lich-Gregoir ureterovesical anastomoses for renal transplantation, together with the related costs and the infectious risk. The benefits in terms of prevention of ureteral complications are evaluated.

Catheterization↗
PubMed2006

Late ureteral stenosis following renal transplantation: risk factors and impact on patient and graft survival.

The aim of this retrospective study of a cohort of 1787 consecutive kidney transplantations was to analyze the risk factors associated with the occurrence of ureteral stenosis and the impact of ureteral stenosis on graft and patient survival. Between January 1990 and December 2002, 1787 renal transplantations were performed at our center. Only stenosis observed after the first month, were considered. Among the parameters studied were: donor age and serum creatinine before procurement; recipient age, cold ischemia time, delayed graft function (DGF), number of arteries and the presence of a double J stent. The follow-up parameters were the number and timing of acute rejection episodes, cytomegalovirus (CMV) infection, acute pyelonephritis, renal function and death. Ureteral stenosis occurred in 4.1% of patients and was correlated with donor age > 65 years (p = 0.001), kidneys with more than 2 arteries (p = 0.009) and DGF (p = 0.016). Ureteral stenosis did not affect 10-year patient and graft survival rates, which were respectively 90% and 64% for the stenosis group, 86% and 63% for the no-stenosis group (p = NS). These data suggest an important role for donor age, number of renal arteries and DGF for the occurrence of ureteral stenosis following renal transplantation.

Adult↗
PubMed2005

[Upper urinary tract: physiology, pathophysiology of obstructions and function assessment].

The urine is transported from the renal papilla to the bladder through the upper urinary tract which allows this transport to be safe and comfortable, i.e., without any risk or pain for the kidney. This active transport depends on the smooth muscle contractile properties. The upper urinary tract is totally autonomous; this feature allows the preservation of its function after renal transplantation. However, despite its accessory role, the autonomous nervous system can modulate its activity. Upper urinary tract obstruction involves adaptative mechanisms which are different depending on the type (acute, chronic, acquired or congenital) of obstruction. Functional evaluations of the upper urinary tract are aimed at identify the urine transport conditions and the relationship between obstruction and clinical conditions such as hydronephrosis, pain or impaired renal function.

Humans↗
PubMed2004

[Penis tumours: techniques and indications].

Although penis epidermoid carcinoma is a relatively rare tumour, early identification and treatment are necessary to avoid mutilating and sometimes morbid surgery. Awareness of disease epidemiology is mandatory for preventing the evolution of an underlying tumour (absent or insufficient hygiene, congenital or acquired phimosis, preepitheliomathous lesions such as Bowen's disease). Conservative surgical or radio-therapeutic techniques may be considered, provided the lesion is superficial and with a diameter < 30 mm. In all other cases, penis amputation is necessary. Penis epidermoid carcinoma spreads by vascular and lymphatic diffusion. Dynamic scintigraphy for the identification of a sentinel node and screening of subclinical metastasis is currently under evaluation. In case of palpable inguinal adenopathy, inguinal lymphadenectomy should be proposed if technically performable. Although superficial lymphadenectomy is associated with a low morbidity rate (about 3% of mild complications) deep inguinal Lymphadenectomy is far more morbid and disabling. Compliance with pre- and post-operative measures, and total patient compliance are necessary to minimize as far as possible such morbidity.

Amputation, Surgical↗
PubMed2004

[Augmentation enterocystoplasty].

Augmentation enterocystoplasty refers to a technique that consists in removing a bowel segment in order to suture it onto the bladder. This technique is indicated in case of reduced bladder capacity and/or compliance, in case of failure of conservative treatments. The goal is to improve the patient's urination comfort, but above all to ensure long-term protection of the upper urinary tract. All bowel segments may be utilized but the ileum is the segment of choice. The selected digestive segment must be detubulized in order to better decrease its peristaltic contractions and obtain low-pressure urine storage. Bi-valving the bladder while preserving the detrusor usually performs augmentation enterocystoplasty. However, in case of very fibrous and thickened detrusor, a supra-trigonal cystectomy should be considered. The digestive segment is removed and detubulized, then it is sutured on to the bladder as a patch at the incision level. Following such surgery, over 90% of the patients report significantly improved quality of life. Nocturnal bladder competence is obtained in more than 90% of the patients, while 91 to 100% report diurnal bladder competence. Long-term complications may be observed, such as chronic infections with asymptomatic bacteruria (70% of the cases) not necessitating any treatment. Within the two first years, there is a 10% to 15% risk for stone formation following intestinal mucus development. Enterocystoplasty perforation may occur at a frequency estimated to range from 5 to 13%, which is a very serious and life-threatening complication. Similarly, a risk of enterocystoplasty cancer may be observed after five to ten years, in 1% of the cases.

Cystectomy↗
PubMed2001

[Lumbar pain and hydrocalyx].

The authors report the case of a patient presenting with disabling left lumbar pain. Complementary investigations confirmed the diagnosis of isolated hydrocalyx with no organic cause. Surgical treatment was conservative with caliceal plasty. The authors discuss the diagnostic and therapeutic management by analogy between this type of hydrocalyx and Fraley's syndrome.

Child↗
PubMed2001

[Substitutive non-modeled uretero-ileoplasty].

OBJECTIVES: To evaluate the indications and results of replacement uretero-ileoplasties performed over the last six years. MATERIAL AND METHODS: Over a period of 6 years, 8 patients underwent subtotal or total replacement uretero-ileoplasty involving a total of 9 renal units. Preoperative temporary urinary diversion was performed in each patient. The mean preoperative serum creatinine was 88 mumol/l (range: 53 to 150). Uretero-ileoplasty was performed for ureteric stricture in 7 cases (bilateral in one case and in a solitary kidney in one case), ureteric necrosis following renal transplantation without a donor ureter in one case and urothelial tumour on a solitary kidney in one case. RESULTS: The mean follow-up was 54 months. The mean operating time was 218 minutes for uretero-unilateral ileoplasties, with a mean length of hospital stay of 12 days (range: 10 to 18 days). The following complications were observed: acute urinary retention, stenosis of the ileo-vesical implantation treated by endoscopic dilatation, 2 incisional hernias after midline laparotomy, one case of stones of the ileo-vesical anastomosis, non-febrile urinary tract infections treated on an outpatient basis. The functional result was considered to be satisfactory in every case. No electrolyte disorders were observed. Mean postoperative serum creatinine was 86 mumol/l (range: 59 to 140). CONCLUSION: In this recent series with a mean follow-up of 4.5 years, replacement uretero-ileoplasty successfully treated partial or total complex ureteric lesions with a low morbidity.

Adolescent↗
PubMed2000

Use of detergents in two-dimensional crystallization of membrane proteins.

Structure determination at high resolution is actually a difficult challenge for membrane proteins and the number of membrane proteins that have been crystallized is still small and far behind that of soluble proteins. Because of their amphiphilic character, membrane proteins need to be isolated, purified and crystallized in detergent solutions. This makes it difficult to grow the well-ordered three-dimensional crystals that are required for high resolution structure analysis by X-ray crystallography. In this difficult context, growing crystals confined to two dimensions (2D crystals) and their structural analysis by electron crystallography has opened a new way to solve the structure of membrane proteins. However, 2D crystallization is one of the major bottlenecks in the structural studies of membrane proteins. Advances in our understanding of the interaction between proteins, lipids and detergents as well as development and improvement of new strategies will facilitate the success rate of 2D crystallization. This review deals with the various available strategies for obtaining 2D crystals from detergent-solubilized intrinsic membrane proteins. It gives an overview of the methods that have been applied and gives details and suggestions of the physical processes leading to the formation of the ordered arrays which may be of help for getting more proteins crystallized in a form suitable for high resolution structural analysis by electron crystallography.

Crystallization↗
PubMed1998

Anatomic bases of aorto-coronary bypasses: the internal thoracic artery and blood supply of the sternum.

The internal thoracic a. is much used in cardiac surgery because of its anatomic position, but its mobilisation may lead to devascularisation of the sternum. The aim of this study was to establish a precise systematisation of the vascularisation of the sternum by means of dissections and radiography after injection of contrast medium in 15 subjects. It is based on the internal thoracic a. and its collaterals, which form multiple anastomoses. This anatomic basis provides an understanding of the problems of the devascularisation (partial and temporary) and the infections that may occur following the use of one or both internal thoracic aa. during coronary bypass operations. However, it should always be regarded as the graft of choice, given the longevity of these bypasses.

Angiography↗
PubMed1998

A new class of wine pigments generated by reaction between pyruvic acid and grape anthocyanins.

A new class of stable red pigments detected in grape pomace was analysed by electrospray ionisation mass spectrometry. They were shown to be pyruvic acid derivatives of genuine grape anthocyanins by synthesis experiments. The major product was identified by NMR (1H, NOE, HSQC, HMBC) experiments as the malvidin-3-monoglucoside pyruvic acid adduct. Its formation results from cyclisation between C-4 and the hydroxyl group at C-5 of the original flavylium moiety with the double bond of the enolic form of pyruvic acid, followed by dehydration and rearomatisation steps. This type of reaction leads to increased colour stability. Various yeast metabolites other than pyruvic acid were shown to react with grape anthocyanins following this mechanism, suggesting that it may be an important route of conversion into stable pigments during the maturation and ageing of wine.

Anthocyanins↗
PubMed1997

In vitro study of passive nitrate transport by native and reconstituted plasma membrane vesicles from corn root cells.

Proteins from phase-partitioned corn root plasma membrane were reconstituted into soybean lipids/egg PC (8:2, w:w) using deoxycholate and rapid gel filtration to eliminate the detergent. All (H+)ATPase molecules were inside-out reinserted and the initial activity was totally recovered in an homogeneous vesicle preparation. In addition, membrane tightness greatly increased, as shown by the size and stability of the response of the fluorescent membrane potential probe (oxonol VI) to an imposed K+ diffusion gradient. Consequently, the H(+)-pumping activity of the (H+)ATPase, monitored with the fluorescent pH probe (ACMA), increased 20-fold after reconstitution. A protein-mediated passive transport of nitrate was first demonstrated by the ability of NO3- to electrically short-circuit the (H+)ATPase in plasma membrane vesicles and not in liposomes containing only the purified enzyme. The passive transport was saturable (K(m) approximately 5 mM), thermolabile, inhibited by the arginine reagent phenylglyoxal, and selective (NO3- > I- approximately ClO3- approximately Br- > Cl- approximately NO2- > Iminodiacetate approximately SO4(2-)). Passive NO3- transport was also determined, independently of the (H+)ATPase, from the NO3(-)-dependent augmentation of the dissipation rate of imposed diffusion potentials. This second transport assay gave similar K(m) for NO3- and should be suitable to continue the functional and biochemical characterization of the NO3- transport system.

Biological Transport↗
PubMed1993

How is leghemoglobin involved in peribacteroid membrane degradation during nodule senescence?

An increase in the rate of succinate and glutamate uptake by isolated symbiosomes from French bean nodules was observed in the presence of iron plus H2O2. The lipid bilayer, and not proteins involved in transport, seems to be the major target of radical attack. Leghemoglobin in the presence of a 6-fold excess of H2O2 (where heme breakdown and iron release occurred) provoked also an increase in peribacteroid membrane permeability. In contrast, this hemoprotein in the presence of a 2-fold excess of H2O2 (where a protein radical was generated) was without effect. We suggest that in vivo the release of heme iron may constitute the major process concerning the involvement of leghemoglobin in the degradation of the peribacteroid membrane during nodule senescence.

Cell Membrane↗
PubMed1993

[Loco-regional anesthesia and orthopedic surgery of the shoulder].

Interscalene block can induce by itself anesthesia for shoulder surgery, if the opening does not reach the delto-pectoral site nor the shoulder-blade, but medical indications must be thoroughly talked over on account of the risk of phrenic paralysis with patients suffering from breezing trouble, and the surgical position that may disturb the anesthesiologist in case he has to increase anesthesia. A superficial cervical plexus block is required in anesthesia of the upper part of the shoulder. Regional anesthesia is quite useful too as a complement to general anesthesia, for it provides excellent postsurgical analgesia. A catheter may be inserted at the end of the surgical process through a nerve stimulator, but the patient does not tolerate it long, its efficiency greatly diminishes after the first day, and paresthesias may occur as after-effects. Today we prefer set interscalene block before the patient is anaesthetized, searching for paresthesias with a thin needle: this process does not take long to install, it is relatively painless and provides excellent analgesia during the per and post-surgical period, until the next day with long acting local anesthetics. Not any complication happened in fifty patients for one year.

Cervical Plexus↗
PubMed1992

delta-Aminolevulinate uptake by Rhizobium bacteroids and its limitation by the peribacteroid membrane in Legume nodules.

Heme is overproduced during Rhizobium-Legume symbiosis and delta-aminolevulinate (ALA) is a common precursor in both bacterial and plant synthesis pathways of this molecule. ALA uptake by bacteroids from French bean and soybean nodules was characterized. The action of several metabolic inhibitors and the competition effect of malate on this uptake were studied. ALA transport appeared to be mediated by the dicarboxylate carrier system. Purified symbiosomes--bacteroids surrounded by the peribacteroid membrane--failed to accumulate significant amount of ALA. These experiments rule out the possibility for the plant cytosol to provide the bacteroid with ALA and strengthen the restrictive role of the peribacteroid membrane for exchanges between the two symbiotic partners.

Aminolevulinic Acid↗
PubMed1992

[Use of a disposable peroperative autotransfusion device in uncomplicated vascular surgery].

We used a simple single process to recover total blood during surgery. All the process stands on a low burdensome jib and does not require additional staff in theater. Its cost is low. The indications concern all surgical operations enduring low or mean bleeding, except in septic and cancer surgery. It may be used in emergencies, even in war surgery with an incorporated source of depression.

Animals↗
PubMed1991

Spontaneous insertion of plant plasma membrane (H+)ATPase into a preformed bilayer.

The purified (H+)ATPase from corn roots plasma membrane inserted spontaneously into preformed bilayer from soybean lipids. The yield of the protein insertion, as measured from its H(+)-pumping activity, increased as a function of lipids and protein concentrations. In optimum conditions, all the (H+)ATPase molecules were closely associated with liposomes, exhibiting a high H(+)-pumping activity (150,000% quenching min-1.mg-1 protein of the probe 9-amino-6-chloro-2-methoxyacridine). The insertion was achieved within a few seconds. No latency of the (H+)ATPase hydrolytic activity was revealed when lysophosphatidylcholine was added to permeabilize the vesicles. This indicated that the (H+)ATPase molecules inserted unidirectionally, the catalytic sites being exposed outside the vesicles ("inside-out" orientation), and thus freely accessible to Mg-ATP. The nondelipidated (H+)ATPase could also functionally insert into bilayer from PC:PE:PG or PC:PE:PI, due to the presence of both hydrophobic defects promoted by PE, and negative phospholipids specifically required by the (H+)ATPase from corn roots. The detergent octylglucoside facilitated the delipidated (H+)ATPase reinsertion probably by promoting both a proper protein conformation and hydrophobic defects in the bilayer. Lysophosphatidylcholine facilitated the delipidated protein insertion only when hydrophobic defects were already present, and thus seemed only capable to ensure a proper protein conformation.

Adenosine Triphosphate↗
PubMed1991

Lipid peroxidation in peribacteroid membranes from French-bean nodules.

Enriched peribacteroid membranes were prepared from Phaseolus vulgaris nodules and, in the presence of metleghemoglobin and H(2)O(2), membranal lipid peroxidation was observed. The initial rate of the reaction was low and increased with time. Ferrous leghemoglobin was unable to induce this peroxidation with H(2)O(2). Thus, it appears that leghemoglobin (IV) is not the activated species involved in this process. Heme plays a role in this peroxidation and the hydroxyl radical is not an intermediate of the reaction. Lipid peroxidation in peribacteroid membranes was also observed in the presence of iron ions. A mixture of iron (III) and iron (II) produced a maximal peroxidation. Senescing nodule extracts were able to provoke membranal lipid peroxidation; they contained nonprotein-bound iron. Peribacteroid membranes were more sensitive than microsomes to peroxidation, as measured by malonaldehyde formation.

Journal Article↗