Biomedical subjects

M Wolff

Publications and source records attributed to M Wolff.

At least 19 recordsLinked to original sources

PubMed2007

Density depletion at solid-liquid interfaces: a neutron reflectivity study.

Neutron reflectivity experiments conducted on self-assembled monolayers (SAMs) against polar (water) and nonpolar (organic) liquid phases reveal further evidence for a density reduction at hydrophobic-hydrophilic interfaces. The density depletion is found at the interface between hydrophobic dodecanethiol (C12) and hexadecanethiol (C16) SAMs and water and also between hydrophilic SAMs (C12/C11OH) and nonpolar fluids. The results show that the density deficit of a fluid in the boundary layer is not unique to aqueous solid-liquid interfaces but is more general and correlated with the affinity of the liquid to the solid surface. In water the variation of pH has only minor influence, while different electrolytes taken from the Hofmeister series seem to increase the depletion. On hydrophobic SAMs an increase in density depletion with temperature was observed, in agreement with Monte Carlo simulations performed on corresponding model systems. The increase in the water density depletion layer is governed by two effects: the surface energy difference between water and the substrate and the chemical potential of the aqueous phase.

Journal Article↗

PubMed2006

Pathways involved in alanyl-glutamine-induced changes in neutrophil amino- and alpha-keto acid homeostasis or immunocompetence.

We examined the effects of DON [glutamine-analogue and inhibitor of glutamine-requiring enzymes], alanyl-glutamine (regarding its role in neutrophil immunonutrition) and alanyl-glutamine combined with L-NAME, SNAP, DON, beta-alanine and DFMO on neutrophil amino and alpha-keto acid concentrations or important neutrophil immune functions in order to establish whether an inhibitor of *NO-synthase [L-NAME], an *NO donor [SNAP], an analogue of taurine and a taurine transport antagonist [beta-alanine], an inhibitor of ornithine-decarboxylase [DFMO] as well as DON could influence any of the alanyl-glutamine-induced effects. In summary, irrespective of which pharmacological, metabolism-inhibiting or receptor-mediated mechanisms were involved, our results showed that impairment of granulocytic glutamine uptake, modulation of intracellular glutamine metabolisation and/or de novo synthesis as well as a blockade of important glutamine-dependent metabolic processes may led to significant modifications of physiological and immunological functions of the affected cells.

Adult↗

PubMed2006

Gastric stump carcinoma - epidemiology and current concepts in pathogenesis and treatment.

AIM: The aim of this article is to review the aetiology, pathology and treatment of gastric stump carcinoma (GSC). GSC is an uncommon tumour; however, the incidence is not declining, so this tumour entity will be encountered in the years to come. METHODS: The electronic literature search was performed in the MEDLINE database to identify relevant studies concerning epidemiology, prognosis, treatment, aetiology and pathology of GSC. The references reported in these studies were used to complete the literature search. RESULTS: Patients subjected to distal gastric resection have a 4-7-fold increased risk of developing GSC, which is attributed mainly to gastroduodenal reflux. Denervation during partial gastrectomy may also contribute to the risk of developing GSC. Gastroduodenal ulcers were the main reason for partial gastrectomy. Both ulcer locations have an increased risk of developing GSC after 20 years. In GSC, Helicobacter pylori seems not to be an important risk factor, contrary to primary gastric cancer, because gastroduodenal reflux impairs the growth of Helicobacter pylori. CONCLUSION: The treatment of choice for GSC should be the total removal of the gastric remnant including at least D2 lymphadenectomy. The pattern of lymph node metastases in GSC may differ from primary gastric cancer, as lymph node metastases have been reported in the jejunal mesentery and the lower mediastinum. Therefore, GSC may require a modified lymphadenectomy to include all important lymph node stations. After radical remnant gastrectomy, GSC has a prognosis not different from primary proximal gastric cancer.

Abdomen↗

PubMed2006

Detection of human aspartyl (asparaginyl) beta-hydroxylase and homeobox B7 mRNA in brush cytology specimens from patients with bile duct cancer.

BACKGROUND AND STUDY AIMS: The diagnosis of bile duct cancer is hampered by the low sensitivity of intraductal brush cytology and forceps biopsy. In the present study real-time reverse transcription polymerase chain reaction (RT-PCR) assays for the detection of human aspartyl (asparaginyl) beta-hydroxylase (HAAH) and homeobox B7 (HoxB7) mRNA from intraductal brush cytology specimens were established. Both markers are overexpressed in biliary cancer cell lines and possibly involved in the pathogenesis of bile duct cancer. PATIENTS AND METHODS: RT-PCR assays were validated for detection limit, in-assay variability, and inter-assay variability. Target gene expression was determined in brush cytology specimens from 16 patients with biliary strictures (11 with histologically proven cholangiocarcinomas and five with benign biliary strictures). RESULTS: The assay was quick (about 3 h), highly sensitive (with detection limits between 3 and 106 molecules), and reproducible (maximum in-assay variability 10.3 %, maximum inter-assay variability 11.8 %). The sensitivity of routine brush cytology alone was 36 % (four of 11 cases), with 100 % specificity. A combination with detection of HoxB7 and HAAH mRNA increased the overall diagnostic sensitivity to 82 %. CONCLUSIONS: Detection of these markers using the RT-PCR assays from brush cytology specimens described here may prove to be a useful additional tool for the diagnosis of bile duct carcinoma.

Adult↗

PubMed2006

Nitric oxide and polyamine pathway-dependent modulation of neutrophil free amino- and alpha-keto acid profiles or host defense capability.

We have examined the effects of N(omega)-nitro-L-arginine-methylester-hydrochloride [L-NAME; inhibitor of nitric oxide synthase], S-nitroso-N-acetyl-penicillamine [SNAP; nitric oxide donor], alpha-difluoro-methyl-ornithine [DFMO; inhibitor of ornithine decarboxylase] arginine or ornithine as well as the combination of arginine or ornithine with L-NAME, SNAP or DFMO on intracellular free amino- and alpha-keto acid profiles and the immune function markers superoxide anion and hydrogen peroxide generation as well as released myeloperoxidase activity in neutrophils (PMN). Although the underlying mechanisms still remain unclear, we believe from our results that nitric oxide as well as polyamine-dependent pathways are involved in the signal transmission of free radical molecule, beneficial nutritional therapy or maleficient pharmacological stress-induced alterations in PMN nutrient composition. Relevant changes in intragranulocyte free amino- and alpha-keto acid homeostasis and metabolism, especially, may be one of the determinants in PMN nutrition that positively or negatively influences and modulate neutrophil host defence capability and immunocompetence.

Adult↗

PubMed2006

Magnetic resonance (MR) imaging and MR angiography for evaluation and follow-up of hepatic artery banding in patients with hepatic involvement of hereditary hemorrhagic telangiectasia.

BACKGROUND: We describe findings obtained by magnetic resonance angiography (MRA) and magnetic resonance imaging (MRI) for evaluation and follow-up after hepatic artery banding in patients with hepatic involvement of hereditary hemorrhagic telangiectasia (HHT). METHODS: Abdominal MRA and liver MRI were performed in three patients with HHT as clinically defined by Curacao criteria. One patient underwent MRA and MRI twice for preinterventional evaluation and follow-up, one patient for preinterventional evaluation, and one patient for postinterventional evaluation. Hepatic vascular involvement of the disease and postinterventional vascular anatomy were evaluated by two radiologists by consensus. RESULTS: Hepatic vascular involvement with perfusion disorders and arteriosystemic shunts was found in all three patients. MRA and MRI allowed diagnostic characterization of hepatic vascular disease (three of three), preinterventional evaluation of complex vascular anatomy and variants (two of two), and postinterventional follow-up of hepatic artery banding (two of two). CONCLUSION: In preinterventional evaluation and postinterventional follow-up, MRA and MRI allows characterization of complex hepatic vascular alterations of HHT and, hence, is an alternative to other imaging modalities in the diagnosis, clinical decision making, and follow-up of HHT.

Aged↗

PubMed2006

[Trauma mechanism and diagnosis of blunt diaphragmatic rupture].

BACKGROUND: Indirect diaphragmatic rupture (DR) is defined as acquired complete split of the diaphragm after blunt trauma and occurs in 1-5% of massively traumatized patients. The diagnosis is often difficult. However, particular trauma mechanisms and associated injuries may suggest the existence of DR. METHODS: A retrospective study was done of 21 consecutive patients from 1993 to 2004 at an university hospital. RESULTS: This study revealed a striking combination of DR with pelvic fractures (12/21, 57%). Of 19 polytraumatized patients, diagnosis was made initially in 13 (68%) and with a delay in six (32%). Right-sided injuries were common (8/21, 38%). Thus a 'protective' function of the liver does not exist. Diaphragmatic rupture can be missed in ventilated patients until extubation leads to herniation of abdominal organs into the thorax. CONCLUSIONS: Diaphragmatic rupture should be excluded in all severely abdominally traumatized patients, in particular those with concomitant pelvic fracture. Computed tomography with oral contrast medium is diagnostic in most cases. Access by laparotomy should be preferred after acute trauma, since additional intra-abdominal injuries are frequent.

Accidental Falls↗

PubMed2006

["Fast-track surgery": Perioperative management].

The multimodal therapeutic concept of fast-track surgery is directed against the pathophysiologic functional changes following elective surgery. This concept has been proven to reduce postoperative morbidity and convalescence. This benefit is based on an interdisciplinary approach by surgeons, anaesthesiologists, nurses, and physiotherapy staff to optimise perioperative care in order to decrease surgically-induced stress. Fast-track surgery after elective colorectal surgery has been shown to reduce the rate of postoperative complications and shorten hospital stay significantly. A prerequisite for successfully implementing this concept is the willingness of the participating surgeons to abandon conventional traditions. In addition to abdominal procedures, the basic concept of fast-track surgery has been successfully instituted in other surgical fields, such as urology.

Abdomen↗

PubMed2006

Procholinergic and memory enhancing properties of the selective norepinephrine uptake inhibitor atomoxetine.

Atomoxetine has been approved by the FDA as the first new drug in 30 years for the treatment of attention deficit/hyperactivity disorder (ADHD). As a selective norepinephrine uptake inhibitor and a nonstimulant, atomoxetine has a different mechanism of action from the stimulant drugs used up to now for the treatment of ADHD. Since brain acetylcholine (ACh) has been associated with memory, attention and motivation, processes dysregulated in ADHD, we investigated the effects of atomoxetine on cholinergic neurotransmission. We showed here that, in rats, atomoxetine (0.3-3 mg/kg, i.p.),--increases in vivo extracellular levels of ACh in cortical but not subcortical brain regions. The marked increase of cortical ACh induced by atomoxetine was dependent upon norepinephrine alpha-1 and/or dopamine D1 receptor activation. We observed similar increases in cortical and hippocampal ACh release with methylphenidate (1 and 3 mg/kg, i.p.)--currently the most commonly prescribed medication for the treatment of ADHD--and with the norepinephrine uptake inhibitor reboxetine (3-30 mg/kg, i.p.). Since drugs that increase cholinergic neurotransmission are used in the treatment of cognitive dysfunction and dementias, we also investigated the effects of atomoxetine on memory tasks. We showed that, consistent with its cortical procholinergic and catecholamine-enhancing profile, atomoxetine (1-3 mg/kg, p.o.) significantly ameliorated performance in the object recognition test and the radial arm-maze test.

Acetylcholine↗

PubMed2006

Tracheal rupture after endotracheal intubation: experience with management in 13 cases.

BACKGROUND: Tracheal rupture is a rare complication of endotracheal intubation. Potential causes, diagnosis, management, and outcome of cases treated at an university hospital are analysed. PATIENTS AND METHODS: This is a retrospective report on thirteen cases of tracheal rupture related to tracheal intubation, treated at our institution from February 1989 to May 2002. In all patients, the tracheal rupture was confirmed by fiberoptic bronchoscopy. RESULTS: Eleven patients underwent primary repair through a right thoracotomy. Three postoperative deaths unrelated to the tracheal lesion occurred. All remaining cases showed an uneventful recovery after surgical therapy. Two lacerations of the cervical part of the trachea were treated nonsurgically with a satisfactory outcome. CONCLUSIONS: Prognosis of tracheal ruptures depends both on the underlying disease and general condition of the patient and on the rapidity of diagnosis and treatment. Surgical therapy is preferred as it allows reconstruction of the trachea and drainage of the mediastinum. Conservative management appears to be justified for small ruptures in the upper third of the trachea without mediastinitis.

Adult↗

PubMed2006

Adults with spontaneous aerobic Gram-negative bacillary meningitis admitted to the intensive care unit.

The characteristics of spontaneous aerobic Gram-negative bacillary meningitis (AGNBM) were determined in 40 adults requiring admission to an intensive care unit (ICU) during a 16-year period in ten French ICUs. Eight infections were hospital-acquired and most patients had predisposing factors, mainly chronic alcoholism and an immunocompromised status. Three immunosuppressed patients had disseminated strongyloidiasis. Gram's stain, cerebrospinal fluid and blood cultures were positive for 85%, 98% and 80% of cases, respectively. Escherichia coli (57%) and Klebsiella pneumoniae (17%) were the most frequent pathogens. In-ICU mortality was 38%. Spontaneous AGNBM is a rare complication of bacteraemia in adults. The severity of predisposing underlying diseases might explain the poor prognosis despite appropriate antimicrobial therapy.

Adult↗

PubMed2005

Alterations in neutrophil (PMN) free intracellular alpha-keto acid profiles and immune functions induced by L-alanyl-L-glutamine, arginine or taurine.

The objective of this study was to determine the dose as well as duration of exposure-dependent effects of L-alanyl-L-glutamine, arginine or taurine on polymorphonuclear neutrophil (PMN) free alpha-keto acid profiles and, in a parallel study, on PMN immune functions. Exogenous L-alanyl-L-glutamine significantly increased PMN alpha-ketoglutarate, pyruvate PMN superoxide anion (O2-) generation, hydrogen peroxide (H2O2) formation and released myeloperoxidase (MPO) activity. Arginine also led to significant increases in alpha-ketoglutarate, pyruvate, MPO release and H2O2 generation. Formation of O2- on the other hand was decreased by arginine. Incubation with taurine resulted in lower intracellular pyruvate and alpha-ketobutyrate levels, decreased O2- and H2O2 formation and a concomitant significantly increased MPO activity. We therefore believe that considerable changes in PMN free-alpha-keto-acid profiles, induced for example by L-alanyl-L-glutamine, arginine or taurine, may be one of the determinants in cell nutrition that considerably modulates the immunological competence of PMN.

Adult↗

PubMed2005

Structure of polymer micelles close to the solid interface. A grazing incidence small angle neutron scattering study.

Block copolymers are widely used in industry. For scientific interests their aqueous solutions offer a model system for the investigation of crystallisation as the macromolecules agglomerate for elevated concentrations into micelles, which crystallise when a critical volume fraction is reached. We report on grazing incidence small angle neutron scattering (GISANS) or near surface small angle neutron scattering (NS-SANS) as an experimental tool to investigate the micelle crystallisation close to interfaces with different chemical termination. We find that in general crystallization is suppressed at a repulsive surface and favoured at an attractive one. Furthermore we show that the crystallization close the interface can be controlled by the micelle stability, resulting from the different composition and length of the monomers. The effect of the interface is found more important for a high micelle stability, whereas for a low stability it is shadowed by adsorbed monomers.

Journal Article↗

PubMed2005

Spectral reflectance and morphologic correlations in eastern Terra Meridiani, Mars.

The Mars Express Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) hyperspectral image data covering eastern Terra Meridiani indicate the ubiquitous presence of molecular water in etched terrain materials that disconformably overlie heavily cratered terrains and underlie the hematite-bearing plains explored by the Opportunity rover. Identification of crystalline water in kieserite (MgSO4.H2O) is linked to materials exposed in a valley and plateau to the north of hematite-bearing plains. The mineralogical similarities between the etched terrain deposits examined with OMEGA data and the layered rocks examined by Opportunity imply that the ancient aqueous environments inferred from analyses of the rover data extend over regional scales.

Extraterrestrial Environment↗

PubMed2005

MRI and proton MR spectroscopy in acute disseminated encephalomyelitis.

INTRODUCTION: Acute disseminated encephalomyelitis (ADEM) is one of a group of demyelinating disorders of the central nervous system (CNS). It is said to be attributed to an overshooting immunologic response following an infection or vaccination. The clinical course and type of manifestation is heterogeneous. The early application of corticosteroids has been shown to be beneficial to outcome; thus, an early diagnosis is highly desirable. METHODS: The potential diagnostic value of advanced MR techniques such as proton MR spectroscopy and diffusion-weighted imaging (DWI) was investigated in two paediatric patients with ADEM, one of whom had a remitting and relapsing clinical course and presented with additional cranial nerve involvement. Proton MR spectroscopy revealed typical signs of acute demyelination, such as increased macromolecules, not found in other forms of non-necrotising pathology. CONCLUSION: The addition of proton MR spectroscopy and DWI adds to the diagnostic power of MRI in the setting of post-infectious demyelinating disorders of the CNS or ADEM and may obviate the need for biopsy.

Adolescent↗

PubMed2005

Two cases of multidrug-resistant Nocardia farcinica infection in immunosuppressed patients and implications for empiric therapy.

Presented here are two cases of multidrug-resistant Nocardia farcinica infection that occurred in immunocompromised patients. One of the patients developed the infection despite being on trimethoprim/sulfamethoxazole prophylaxis for Pneumocystis jiroveci. These cases demonstrate the propensity of Nocardia spp. to cause disseminated disease and to develop resistance to multiple antimicrobial agents used in the initial treatment of serious Nocardia infection. These factors lead to the conclusion that empiric monotherapy with trimethoprim/sulfamethoxazole may not be sufficient. Treatment with a combination regimen of imipenem and amikacin may be a more promising initial therapy.

Aged↗

PubMed2005

[Surgical treatment of portal hypertension].

A switch to decompressive shunt procedures is mandatory if endoscopic therapy fails to control recurrent variceal hemorrhage. Surgical shunt procedures continue to be safe, highly effective and durable procedures to control variceal bleeding in patients with low operative risk and good liver function (Child A). In cirrhotics, elective operations using portal flow preserving techniques such as a selective distal splenorenal shunt (Warren) or a partial portocaval small diameter interposition shunt (Sarfeh) should be preferred. Rarely, end-to-side portocaval shunt may serve as a salvage procedure if emergent endoscopic treatment or TIPS insertion fail to stop bleeding. Until definitive results from randomized trials are available patients with good prognosis (Child-Pugh A and B) can be regarded as candidates for surgical shunts. For patients with noncirrhotic portal hypertension, in particular with extrahepatic portal vein thrombosis, portosystemic shunt surgery represents the only effective therapy which leads to freedom of recurrent bleeding and repeated endoscopies for many years, and improves hypersplenism without deteriorating liver function or encephalopathy. Gastroesophageal devascularization and other direct variceal ablative procedures should be restricted to treat endoscopic therapy failures without shuntable portal tributaries.

Esophageal and Gastric Varices↗

PubMed2005

[Radiologic features of inflammatory pseudotumors].

Inflammatory pseudotumor is a rare benign tumor entity. Because inflammatory pseudotumors mimic malignant tumors both clinically and radiologically, the radiologist should be familiar with this entity. Inflammatory pseudotumor most commonly involves the lung and the orbit, but it has been reported to occur in nearly every site in the body. For making a definite diagnosis a biopsy is often essential. The treatment options are varied and consist of surgery, high-dose steroids, irradiation, and chemotherapeutics.

Adult↗