Beta-structure in the membrane-spanning part of the nicotinic acetylcholine receptor (or how helical are transmembrane helices?).

The 'four-transmembrane-helix receptors' transmit their signals from the extracellular space to the cytoplasm via an intramembrane domain. In the case of the nicotinic acetylcholine receptor this domain comprises an ion channel formed by homologous secondary structure elements in the receptor subunits. It was believed to be exclusively alpha-helical, but recent experimental evidence questions the widely accepted model: beta-strands seem to be part of the membrane-spanning domain.

Hemodynamic effects of hypertonic hydroxyethyl starch 6% solution and isotonic hydroxyethyl starch 6% solution after declamping during abdominal aortic aneurysm repair.

Fluid resuscitation with hypertonic hydroxyethyl starch solutions (HES) is effective in haemorrhagic shock due to the rapid mobilisation of fluids into the intravascular compartment. Declamping of the abdominal aorta with acute redistribution of blood into the vessels of the lower body half causes declamping-induced hypotension. Usually large amount of fluids or vasopressors are necessary to restore hemodynamic stability. Therefore, infusion of a hypertonic colloid solution may be an attractive option to achieve hemodynamic stability. This study was conducted to determine the amount of fluid of either hypertonic HES (HES 6%;7.2% NaCl) or isotonic HES (HES 6%;0.9% NaCl) needed to attain best wedge pressure (PCWP) cardiac index (CI) relation after declamping. Thirty-two high-risk patients undergoing elective abdominal aneurysm resection were enrolled in a prospective, randomised, double blinded study. The individual optimised PCWP/CI relation was determined after induction of anaesthesia. After declamping, both solutions were titrated in small boluses of 100 mL until the previously determined best wedge was reached. The amount of fluid after declamping was significantly reduced in the hypertonic HES- group 162 mL vs. 265 mL in the control group (P < 0.05). Resuscitation time was shortened, and cardiac index was slightly higher in the treatment group. The use of hypertonic HES-solution after aortic declamping led to a significant reduction of fluids necessary to attain optimised PCWP/CI relation. In this clinical trial with moderate blood loss in high-risk patients, hypertonic HES applied in a titrated fashion restored hemodynamic stability faster and without volume overload.

Ivermectin toxicosis in a dog.

A 5-year-old male Doberman Pinscher was examined after ingesting an equine paste dewormer containing approximately 115 mg of ivermectin. Clinical signs consisted of profound hypothermia, mild dehydration, dilated unresponsive pupils, localized muscle group fasciculations around the face and hind limbs, and no response to any external stimuli. Twelve days after parenteral administration of isotonic fluids and IV administration of dexamethasone and dimethyl sulfoxide, the dog returned to a clinically normal neurologic state. Ivermectin toxicosis has been reported frequently in Collies; however, other breeds may have idiosyncratic reactions to low doses. Patients with severe toxicosis should eventually recover completely if given appropriate intensive care.

[Hyperthyroidism associated with pulmonary hypertension]. / Hyperthyroïdie associée à une hypertension artérielle pulmonaire.

The association of pulmonary hypertension and polyendocrinopathies or connective tissue diseases has been reported by several authors. The causes of this form of pulmonary hypertension are not clear but an autoimmune process has often been proposed. The authors report a case of non-autoimmune hyperthyroidism and reversible pulmonary hypertension after total thyroidectomy and normalisation of thyroid function. This case supports the hypothesis of a non-autoimmune aetiology of some causes of pulmonary hypertension in diseases of the thyroid.

[Pulmonary embolism disclosing activated protein C resistance]. / Embolie pulmonaire révélant une résistance à la protéine C activée.

Resistance to the activation of protein C is a recently discovered constitutional anomaly of coagulation which is responsible for thromboembolic events in young subjects. We report a case in a 26 year old man who presented with pulmonary embolus. Laboratory data was characterised by an absence of any lengthening of the activated cephaline time after adding purified activated exogenous Protein C. The confirmation of this anomaly is provided by the evidence of a mutation Arg 506 to Gln of Factor 5. The outcome is favourable with treatment by Heparin then by anti-Vitamin K.

[The multifocal form of bronchocentric granulomatosis]. / Granulomatose bronchocentrique à forme multifocale.

Bronchocentric granulomatosis is a rare entity and has only recently been characterised. We report a case of a forty-three year old man presenting with multifocal bronchocentric granulomatosis which was revealed following some oto-rhino-laryngological and bronchopulmonary symptoms. The open lung biopsy confirmed the diagnosis. Treatment was by bolus doses of corticosteroids (30 mg/kg) and of methotrexate in low dosage (7.5 mg/week, then 15 mg/week) which checked the initially unfavourable outcome.

[Dermatomyositis and small-cell lung cancer : fortuitous association or paraneoplastic syndrome?]. / Dermatomyosite et cancer à petites cellules: association fortuite ou syndrome paranéoplasique ?

Dermatomyositis, an inflammatory muscle disease probably related to dysimmunity, is associated with character skin eruptions. Dermatomyositis is often associated with cancer (15 to 40% of cases depending on the series). All histological types and all cancer localizations observed in the general population can be associated with dermatomyositis. We report the case of a patient with dermatomyositis who developed small-cell lung cancer. There have been few descriptions of this association in the literature. Certain clinical features of dermatomyositis would be predictive of its paraneoplastic nature. Prognosis is very poor. Treatment is basically dictated by the underlying neoplasia.

[Acute postoperative respiratory insufficiency of uncommon cause]. / Insuffisance respiratoire aiguë post-opératoire de cause inhabituelle.

We report a case of acute respiratory distress which occurred three days after orthopaedic surgery and which led to the diagnosis of spontaneous rupture of the oesophagus (Boerhaave syndrome). The unusual nature of the signs delayed diagnosis.

[A rare cause of chronic respiratory insufficiency: arthrogryposis in adults]. / Une cause rare d'insuffisance respiratoire chronique: l'adulte.

Arthrogryposis is a congenital disease leading to multiple joint ankylosis in utero observed as sequellae at birth. Deformation of the chest produces respiratory failure usually seen at birth. We report a case in an adult which required intermittent nocturnal positive pressure nasal ventilation.

[Acute COPD exacerbations in women: EABPCO-CPHG study by the College of general hospital pneumologists]. / Les exacerbations aiguës de BPCO chez la femme : étude EABPCO-CPHG du Collège des pneumologues des hôpitaux généraux.

INTRODUCTION: Emerging evidence suggests that gender differences exist in the prevalence, susceptibility, severity and response to the treatment of COPD. This article compares the characteristics of acute exacerbation in male and female patients hospitalized for acute chronic obstructive pulomnary disease (COPD) exacerbation. METHODS: This observational study collected data from 1,824 patients admitted to the pneumology department in 68 general hospitals between October 2006 and June 2007. RESULTS: The 423 (23.2%) women were younger than the men (69.1 versus 70.6 years; p=0.016) and more frequently non-smokers (14.4% versus 4.2%; p<0.0001). Before the acute exacerbation, they more frequently reported asthma (18% versus 11.6%; p=0.0006) or bronchiectasis (10.4% versus 5.9%; p=0.002). They also more often presented consciousness disorders (6.4% versus 3.9%; p=0.033) and desaturation (SpO2<90%: 50.4% versus 42%; p=0.002) during acute exacerbation and their hypercapnia was more severe (50.7 versus 46.5mmHg; p<0.0001). During hospitalization, they were more frequently ventilated (23.9 versus 17.1%; p=0.002). There was no difference in the mortality between the sexes (1.4% versus 2.8%; p=0.11). Age and smoking behavior were closely related in the female patients: the smokers were younger (62.5 years) than the ex-smokers (73.7 years) or non-smokers (78.1 years). Of the six women who died during hospitalization, two were smokers and four ex-smokers. In addition, four were over 80 years old. CONCLUSION: The women hospitalized for acute COPD exacerbation differed from the men with respect to risk factors, steady-state COPD severity and exacerbation severity.

All potential glycosylation sites of the nicotinic acetylcholine receptor delta subunit from Torpedo californica are utilized.

All possible N-glycosylation sites of the delta subunit of the nicotinic acetylcholine receptor from Torpedo californica electric tissue are utilized. By a combination of microsequencing and mass spectrometry, it was shown that a high-mannose-type oligosaccharide is bound at Asn143 of the delta subunit. The oligosaccharides at positions Asn70 and Asn208 of the delta subunit are probably of the complex type. The utilized glycosylation sites pose restrictions on possible transmembrane folding models of the subunit.

The glycosylated matrix protein of Borna disease virus is a tetrameric membrane-bound viral component essential for infection.

Borna disease virus (BDV) is representative of the family of Bornaviridae in the order Mononegavirales (negative-stranded, non-segmented, enveloped RNA viruses). It is the causal agent for Borna disease, characterized as an encephalomyelitis (typical form) in a wide variety of domestic animals (from rodents to birds). Recent information shows the involvement of BDV in the pathogenesis of some human psychiatric disorders. The 8.9-kb viral antigenome codes for five major ORF. The third ORF codes for a 16-kDa protein (matrix protein) that is posttranslationally modified, yielding an N-linked glycoprotein. Our data show that the glycosylated matrix protein exists as a stable tetrameric structure detectable either by electrospray ionization or matrix-assisted laser-desorption ionization mass spectrometry. Under native conditions, the tetramer, with a relative molecular mass of 68 kDa, was isolated from a sediment-free brain suspension of a BDV-infected horse. The 68-kDa entity is stable in the presence of ionic and nonionic detergents but dissociates into subunits when heated. We found that the tetrameric matrix protein inhibits in vitro BDV infection in a dose-dependent manner. In contrast to inhibition of BDV infection with hydrophobic carbohydrate derivatives and protein-bound glycoconjugates, the glycosylated matrix protein is a very potent inhibitor of BDV infection, indicating that this protein represents an essential virus-specific membrane component for viral attachment.

The transmembrane domains of the nicotinic acetylcholine receptor contain alpha-helical and beta structures.

The transmembrane domain of the nicotinic acetylcholine receptor (nAChR) from Torpedo californica electric tissue contains both alpha-helical and beta structures. The secondary structure was investigated by Fourier transform infrared (FTIR) spectroscopy after the extramembrane moieties of the protein from the extracellular and intracellular sides of the membrane were removed by proteolysis using proteinase K. The secondary structure composition of this membrane structure was: alpha-helical 50%, beta structure and turns 40%, random 10%. The alpha-helices are shown to be oriented with respect to the membrane plane in a way allowing them to span the membrane, while no unidirectional structure for the beta structures was observed. These findings contradict previous secondary structure models based on hydropathy plots alone.