Making ends meet: the importance of the N- and C-termini for the structure, stability, and function of the third SH3 domain of CIN85.

SH3 domains are common structure, interaction, and regulation modules found in more than 200 human proteins. In this report, we studied the third SH3 domain from the human CIN85 adaptor protein, which plays an important role in both receptor tyrosine kinase downregulation and phosphatidylinositol 3 kinase inhibition. The structure of this domain includes an additional 90° kink after the last canonical ß-strand and features unusual interactions between the termini well outside the boundaries of the standard SH3 domain definition. The extended portions of the domain are well-structured and held together entirely by side chain-side chain interactions. Extensive expression screening showed that these additional contacts provide significantly increased stability to the domain. A similar 90° kink is found in only one other SH3 domain structure, while side chain contacts linking the termini have never been described before. As a result of the increased size of CIN85 SH3 domain C, the proximal proline rich region is positioned such that a possible intramolecular interaction is structurally inhibited. Using the key interactions of the termini as the basis for sequence analysis allowed the identification of several SH3 domains with flanking sequences that could adopt similar structures. This work illustrates the importance of careful experimental analysis of domain boundaries even for a well-characterized fold such as the SH3 domain.

[The post-traumatic pancreatitis: about four cases]. / La pancréatite post-traumatique: à propos de quatre cas.

The post-traumatic pancreatitis is the main reason of mortality in the traumatisms of the pancreas, its concurrence is related to the lesions of the pancreatic channels. It represents only 1% of the pancreatitis. In a descriptive retrospective study, four cases of post-traumatic pancreatitis are described.

[Cerebellum abscess: first demonstration of undiagnosed infective endocarditis in an adult with corrected transposition arteries]. / Abcès du cervelet révélant une greffe oslérienne sur une transposition corrigée des gros vaisseaux chez l'adulte.

Neurological complications occur in approximately 30% of all patients with infective endocarditis and represent a major factor associated with an increased mortality rate. Third of these complications is represented by cerebral embolism, followed by mycotic aneurysm, meningitis or meningoencephalitis. Brain abscesses are rare; their localization to the cerebellum is exceptional. A case of cerebellum abscess occurring in a 34-year-old patient with non-operated corrected transposition of the great arteries is reported. Occurrence of this abscess was the first demonstration of undiagnosed infective endocarditis.

Evidence for the expression of three different BoLA-class II molecules on the bovine BL-3 cell line: determination of a non-DR non-DQ gene product.

Studies were conducted to determine the reactivity of six monoclonal antibodies specific for major histocompatibility complex class II molecules expressed on a bovine B cell line homozygous for BoLA-DR and BoLA-DQ alleles. Direct immunoprecipitation, serial immunodepletion experiments, and two-dimensional gel electrophoresis revealed that these antibodies reacted with three different molecules. Bovine orthologues of HLA-DR were recognized by three monoclonal antibodies--H34A, TH12A, and TH14B. Orthologues of HLA-DQ were characterized by two other monoclonal antibodies, TH22A and TH81A. A third BoLA class II antigen, neither DR nor DQ was revealed by the last monoclonal antibody H42A. The relation of this molecule to known molecules in humans and other species remains to be established. However, cumulative data suggest that the determinant is expressed on a molecule related to HLA-DP.

On the involvement of electron transfer reactions in the fluorescence decay kinetics heterogeneity of proteins.

Time-resolved fluorescence study of single tryptophan-containing proteins, nuclease, ribonuclease T1, protein G, glucagon, and mastoparan, has been carried out. Three different methods were used for the analysis of fluorescence decays: the iterative reconvolution method, as reviewed and developed in our laboratory, the maximum entropy method, and the recent method that we called "energy transfer" method. All the proteins show heterogeneous fluorescence kinetics (multiexponential decay). The origin of this heterogeneity is interpreted in terms of current theories of electron transfer process, which treat the electron transfer process as a radiationless transition. The theoretical electron transfer rate was calculated assuming the peptide bond carbonyl as the acceptor site. The good agreement between experimental and theoretical electron-transfer rates leads us to suggest that the electron-transfer process is the principal quenching mechanism of Trp fluorescence in proteins, resulting in heterogeneous fluorescence kinetics. Furthermore, the origin of apparent homogeneous fluorescence kinetics (monoexponential decay) in some proteins also can be explained on the basis of electron-transfer mechanism.

Solvation energetics and conformational change in EF-hand proteins.

Calmodulin and other members of the EF-hand protein family are known to undergo major changes in conformation upon binding Ca(2+). However, some EF-hand proteins, such as calbindin D9k, bind Ca(2+) without a significant change in conformation. Here, we show the importance of a precise balance of solvation energetics to conformational change, using mutational analysis of partially buried polar groups in the N-terminal domain of calmodulin (N-cam). Several variants were characterized using fluorescence, circular dichroism, and NMR spectroscopy. Strikingly, the replacement of polar side chains glutamine and lysine at positions 41 and 75 with nonpolar side chains leads to dramatic enhancement of the stability of the Ca(2+)-free state, a corresponding decrease in Ca(2+)-binding affinity, and an apparent loss of ability to change conformation to the open form. The results suggest a paradigm for conformational change in which energetic strain is accumulated in one state in order to modulate the energetics of change to the alternative state.

[Polymorphism of the microsatellites and tumor necrosis factor genes in chronic inflammatory bowel diseases]. / Etude du polymorphisme des microsatellites et des gènes du tumor necrosis factor (TNF) au cours des maladies inflammatoires chroniques de l'intestin.

OBJECTIVES: Multiplex family studies have excluded chromosome 6 as a candidate gene of susceptibility to inflammatory bowel disease. However, one recent study suggested that a gene involved in the pathogenesis of Crohn's disease is located on chromosome 6 confering to a microsatellite allelic combination (a2, b1, c2, d4, e1) a strong genetic risk factor in Crohn's disease. The aim of our study was to determine simultaneously the polymorphisms of the TNF microsatellites and of the genes coding for TNF synthesis in patients with inflammatory bowel disease. PATIENTS AND METHODS: Sixty patients with ulcerative colitis, 100 patients with Crohn's disease were compared to 64 healthy ethnically matched controls. Five TNF microsatellite loci (a, b, c, d, e) were typed using polymerase chain reaction PCR, and two dimorphisms of TNF alpha and TNF beta (intron 1) were studied by restriction fragment length polymorphism (RFLP). RESULTS: Allelic frequencies of TNF microsatellites and of TNF alpha and beta genes were similar in Crohn's disease, ulcerative colitis and controls. Five loci microsatellite haplotypes, especially a2 b1 c2 d4 e1 allelic combination, were not more frequent in Crohn's disease (25%) compared to ulcerative colitis (27%) or controls (20%). Subgroups stratification according to clinical characteristics did not modify haplotype frequencies. Analysis of our data taking simultaneously into account the MHC alleles (DRB*01 or DRB1*04) did not modify our data; however, it suggested that extended haplotype on short arm of chromosome 6 differed between patients and controls. Linkage disequilibrium (delta = -360.10(-4); P < 0.01) between a2, b1, c2, d4, e1 allelic combination and DRB1*04 allele was observed only in Crohn's disease. CONCLUSION: Percentages of patients with Crohn's disease or ulcerative colitis carrying TNF microsatellite or TNF alpha and beta gene haplotypes were similar to those of healthy controls. These data argue against involvement of the TNF locus without exclusion of short arm of chromosome 6 implication in Crohn's disease pathogenesis.

[Behcet's disease with multiple intracranial arterial aneurysms. Report of a case]. / Maladie de Behçet avec anévrismes artériels intracrâniens multiples. A propos d'un cas.

Behçet disease is a rare condition in central Europe but more common in Morocco. A case of multiple intracranial arterial aneurysms occurring in a 44 year-old Moroccan patient with 2-years history of Behçet's disease is reported. CT-scan showed an infarction in the right middle cerebral artery territory. Panangiography showed sacciform aneurysms of the bifurcation of the right and left middle cerebral arteries. The draining veins and sinuses were normal. The two aneurysms were successfully clipped by two microsurgical frontotemporal approach in one surgical time. There have been only eight reports of intracranial arterial aneurysms associated to Behçet disease in the literature.

[Apropos of a case of acute pancreatitis revealing cystic dilatation of the common bile duct]. / A propos d'un cas de pancréatite aiguë révélant une dilatation kystique du cholédoque.

Dilatation of the common bile duct is rarely caused by cystic formations. Though the pathogenesis is uncertain, congenital disorders have been suggested. Most cases are observed in small children (80% female predominance) with only 20% of the cases reported in adults. Clinical signs vary. Recurrent acute pancreatitis has been reported but is rare. New imaging techniques using CT-scan cholangiography and sometimes MR cholangiography have greatly improved the diagnostic approach. MR of the bile ducts is a recent noninvasive technique enabling an analysis of the biliopancreatic ducts without contrast injection into the bile. To our knowledge, cystic dilatation of the common bile duct has not been previously reported in the literature. We report an interesting case in a 25-year-old woman who developed an episode of acute pancreatitis during the post partum period. We describe the clinical aspects and the different imaging findings, including magnetic resonance cholangiography results.

[Myocardial rhabdomyolysis following paraphenylene diamine poisoning]. / Rhabdomyolyse du myocarde après intoxication par la paraphénylène diamine.

Acute intoxication with paraphenylene diamine, a mineral compound used as hair dye, associated asphyxia due to cervical oedema and rhabdomyolysis. We report the case of a patient with lethal cardiogenic shock secondary to myocardial rhabdomyolysis confirmed by a postmortem biopsy.

[Tension pneumopericardium: a rare complication after thoracic stab wound]. / La tamponnade gazeuse: une complication rare des plaies thoraciques.

The authors report a case involving a patient with thoracic stab wound. The patient developed tension pneumopericardium with acute cardiac tamponade. The clinical and radiological features of tension pneumopericardium and its treatment are discussed.

[Puffer fish poisoning]. / Intoxication par le poisson coffre.

We report three cases of a collective tetrodotoxin poisoning, after ingestion of puffer fish eggs. This neurotoxin is the most potent membrane stabilizer, blocking the nervous conduction and resulting in death from respiratory paralysis in case of massive ingestion. The father died at admission, the mother and her daughter presented an acute respiratory failure and a flaccid tetraplegia, with favourable outcome after 24 hours.

[Traumatic asphyxia or Perthe's syndrome. Six cas reports]. / Syndrome d'asphyxie traumatique ou syndrome de Perthes. A propos de six cas.

Perthe's syndrome or traumatic asphyxia is a clinical syndrome associating cervicofacial cyanosis, petechia and subconjonctival hemorrhage to neurological symptoms. This syndrome appears after severe and transient compressive blunt chest injury. A Valsalva maneuver is necessary before thoracic compression for the development of this syndrome. The treatment includes rapid chest decompression and cardiopulmonary resuscitation. The prognosis is good but a prolonged thoracic compression could lead to cerebral anoxia and neurological sequelae. We report six cases of Perthe's syndrome most of them resulting from thoracic compression after road traffic accidents. All of them made a good prognosis.

[Haemocholecyst: a rare complication of anticoagulant treatment]. / Hémocholécyste: complication rare du traitement antithrombotique.

We report a case of a 50-year-old woman, taking antivitamin K for double mitro-aortic valvular replacement, having presented a clinical picture of acute cholecystitis with marked hypotension. The radiological and biologic exams showed a deep hypocoagulability, vesicular gallstones, a haemoperitoneum and retroperitoneal haematoma. After correction of biological anomalies, the patient was operated. The gallbladder was distended containing large clots and four stones without any evidence of perforation. One of the gallstones led to cystic duct obstruction. Haemocholecyst is a rare complication of anticoagulant therapy, which may occur in the setting of gallbladder stones. The usual complication was the vesicular perforation. In spite of its rarity, haemocholecyst should be suspected when an anticoagulant treated patient presents symptoms of acute cholecystis with or without haemorrhagic shock.

[Traumatic thrombosis of the inferior vena cava]. / Thrombose post-traumatique de la veine cave inférieure.

Traumatic thrombosis of vena cava is rare. Thrombosis of the inferior vena cava diagnosed by uroscanner after blunt abdominal trauma involving the kidney is reported. The Doppler exam confirmed the floating character of the clot. Three days after the initiation of anticoagulant therapy, the thrombus disappeared without any clinical or radiological signs of pulmonary embolism. Fifteen cases of traumatic thrombosis of the inferior vena cava have been described in the literature. Mechanisms, clinical pictures and the management are discussed.

Long-range effects on calcium binding and conformational change in the N-domain of calmodulin.

Proteins within the EF-hand protein family exhibit different conformational responses to Ca(2+) binding. Calmodulin and other members of the EF-hand protein family undergo major changes in conformation upon binding Ca(2+). However, some EF-hand proteins, such as calbindin D9k (Clb), bind Ca(2+) without a significant change in conformation. Here, we investigate the effects of replacement of a leucine at position 39 of the N-terminal domain of calmodulin (N-Cam) with a phenylalanine derived from Clb. This variant is studied alone and in the context of other mutations that affect the conformational properties of N-Cam. Strikingly, the introduction of Phe39, which is distant from the calcium binding sites, leads to a significant enhancement of Ca(2+) binding affinity, even in the context of other mutations which trap the protein in the closed form. The results yield novel insights into the evolution of EF-hand proteins as calcium sensors versus calcium buffers.

The DA6-147 monoclonal antibody raised against the HLA-DR alpha chain identifies a cryptic epitope on the BoLA-DR alpha chain.

By combining immunoprecipitation of BoLA molecules with monoclonal antibodies raised against 2 different major histocompatibility class II antigens, TH14B and TH81A, and western blotting using the anti-HLA DR alpha monoclonal antibody DA6-147, we characterized an epitope conserved on BoLA- and HLA-DR alpha chains. This epitope, not accessible on intact cells, was revealed after cell lysis. In addition, these results allowed us to define TH14B as an anti-BoLA-DR monoclonal antibody whereas TH81A, raised against the products of a second MHC locus, is probably an anti-BoLA-DQ monoclonal antibody.

A novel BoLA class II molecule with a tissue distribution different from BoLA-DR or BoLA-DQ molecules.

This study was designed to investigate the lymphoid tissue distribution of a new BoLA class II molecule defined by a unique monoclonal antibody H42A. We immunostained various lymphoid organs of 4-month-old Holstein calves with this monoclonal antibody and compared its tissue distribution to the BoLA-DR and BoLA-DQ expressions. Our results demonstrate a unique tissue distribution of the H42A-defined molecules, restricted to epithelial cells of the thymic medulla but extending in the periphery to the different cells involved in antigen presentation (B-cells, macrophages and dendritic cells). The peculiar distribution of this new BoLA class II molecule suggests that it has a specific function.

Time-resolved fluorescence investigation of the human immunodeficiency virus type 1 nucleocapsid protein: influence of the binding of nucleic acids.

Depending on the HIV-1 isolate, MN or BH10, the nucleocapsid protein, NCp7, corresponds to a 55- or 71-amino acid length product, respectively. The MN NCp7 contains a single Trp residue at position 37 in the distal zinc finger motif, and the BH10 NCp7 contains an additional Trp, at position 61 in the C-terminal chain. The time-resolved intensity decay parameters of the zinc-saturated BH10 NCp7 were determined and compared to those of single-Trp-containing derivatives. The fluorescence decay of BH10 NCp7 could be clearly represented as a linear combination (with respect to both lifetimes and fractional intensities) of the individual emitting Trp residues. This suggested the absence of interactions between the two Trp residues, a feature that was confirmed by molecular modeling and fluorescence energy transfer studies. In the presence of tRNAPhe, taken as a RNA model, the same conclusions hold true despite the large fluorescence decrease induced by the binding of tRNAPhe. Indeed, the fluorescence of Trp37 appears almost fully quenched, in keeping with a stacking of this residue with the bases of tRNAPhe. Despite the multiple binding sites in tRNAPhe, the large prevalence of ultrashort lifetimes, associated with the stacking of Trp37, suggests that this stacking constitutes a major feature in the binding process of NCp7 to nucleic acids. In contrast, Trp61 only stacked to a small extent with tRNAPhe. The behavior of this residue in the tRNAPhe-NCp7 complexes appeared to be rather heterogeneous, suggesting that it does not constitute a major determinant in the binding process. Finally, our data suggested that the binding of NCp7 proteins from the two HIV-1 strains to nonspecific nucleic acid sequences was largely similar.

Sedation with sufentanil and midazolam decreases pain in patients undergoing upper limb surgery under multiple nerve block.

Multiple nerve blocks may be painful and a source of discomfort. We assessed the efficacy of sufentanil 5 microg combined with midazolam 1 mg in decreasing pain in outpatients after a midhumeral multiple nerve stimulation technique. Visual analog scores for pain were significantly lower in those patients who received sedation before the block, both at the time of block performance (14 +/- 1 vs 27 +/- 2 mm, P < 0.0001) and at discharge (11 +/- 1 vs 24 +/- 2 mm, P < 0. 0001). We conclude that the association of sufentanil and midazolam produced minimal sedation while significantly reducing pain experienced by patients undergoing multiple nerve stimulation.