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Biomedical subjects

M Braun

Publications and source records attributed to M Braun.

At least 19 recordsLinked to original sources
PubMed2006

Rhizoids and protonemata of characean algae: model cells for research on polarized growth and plant gravity sensing.

Gravitropically tip-growing rhizoids and protonemata of characean algae are well-established unicellular plant model systems for research on gravitropism. In recent years, considerable progress has been made in the understanding of the cellular and molecular mechanisms underlying gravity sensing and gravity-oriented growth. While in higher-plant statocytes the role of cytoskeletal elements, especially the actin cytoskeleton, in the mechanisms of gravity sensing is still enigmatic, there is clear evidence that in the characean cells actin is intimately involved in polarized growth, gravity sensing, and the gravitropic response mechanisms. The multiple functions of actin are orchestrated by a variety of actin-binding proteins which control actin polymerisation, regulate the dynamic remodelling of the actin filament architecture, and mediate the transport of vesicles and organelles. Actin and a steep gradient of cytoplasmic free calcium are crucial components of a feedback mechanism that controls polarized growth. Experiments performed in microgravity provided evidence that actomyosin is a key player for gravity sensing: it coordinates the position of statoliths and, upon a change in the cell's orientation, directs sedimenting statoliths to specific areas of the plasma membrane, where contact with membrane-bound gravisensor molecules elicits short gravitropic pathways. In rhizoids, gravitropic signalling leads to a local reduction of cytoplasmic free calcium and results in differential growth of the opposite subapical cell flanks. The negative gravitropic response of protonemata involves actin-dependent relocation of the calcium gradient and displacement of the centre of maximal growth towards the upper flank. On the basis of the results obtained from the gravitropic model cells, a similar fine-tuning function of the actomyosin system is discussed for the early steps of gravity sensing in higher-plant statocytes.

Actomyosin↗
PubMed2006

Experimental results of mesh fixation by a manual manipulator in a laparoscopic inguinal hernia repair model.

BACKGROUND: Laparoscopic mesh fixation using a stapler can lead to complications such as nerve injury and bowel injury. However, mesh fixation by suturing with conventional laparoscopic instruments (CLI) is difficult because of limited degrees of freedom. A manual manipulator--Radius Surgical System (Radius)--whose tip can deflect and rotate, gives the surgeon two additional degrees of freedom. The aim of this study is to evaluate the introduction of Radius to mesh fixation in laparoscopic inguinal hernia repair. METHODS: A model for inguinal hernia repair was prepared using animal organs in a trainer. Mesh fixation was performed using Radius, stapler, and CLI. Tensile strength during extraction of mesh toward the vertical direction, and execution time, were measured. RESULTS: The mean number of fixation points of Radius, stapler, and CLI was 9.3 +/- 1.5, 8.5 +/- 1.4, and 9.0 +/- 1.0, respectively. The mean tensile strength of fixation of mesh of Radius, stapler, and CLI was 140.7 +/- 48.9, 73.1 +/- 23.4, and 53.6 +/- 31.5 (N), respectively. The mean tensile strength per one fixation point by Radius, stapler, and CLI was 16.5 +/- 5.3, 8.7 +/- 2.8, and 6.3 +/- 3.6 (N), respectively. The mean execution time of Radius, stapler, and CLI was 479 +/- 108, 54 +/- 31, and 431 +/- 77 (sec), respectively. CONCLUSIONS: The mesh fixation by Radius was stronger than that by staples and CLI. Two additional degrees of freedom were useful in difficult angles. The introduction of Radius is feasible and facilitates the fixation of mesh with sutures in laparoscopic inguinal hernia repair.

Animals↗
PubMed2006

Investigation by bioassay of the efficacy of sodium hydroxide treatment on the inactivation of mouse-adapted scrapie.

Sodium hydroxide (NaOH) has been shown to reduce the infectivity of transmissible spongiform encephalopathy (TSE) agents. This study investigated the efficacy of sodium hydroxide at 0.1M, 0.25M and 0.5M concentrations for the inactivation of mouse-adapted scrapie strain ME7. Times and temperatures modelled conditions used in an industrial plasma fractionation plant for sanitisation of ultrafilters, and the sodium hydroxide component of Clean In Place sanitisation. The concentration of scrapie ME7 brain homogenate in NaOH test solutions was 1% (w/v). At the end of incubation periods, the samples were adjusted to neutral pH prior to intracerebral inoculation into mice for bioassay. The conditions of 0.1M NaOH at 60 degrees C for 2min and 0.25M NaOH at 30 degrees C for 60min were found to inactivate 3.96 and 3.93logs of scrapie, respectively. Use of 0.5M NaOH at 30 degrees C for 60 or 75min was found to inactivate >or=4.23 and 4.15logs of scrapie. This indicates that the use of these conditions in an industrial process would substantially reduce prion infectivity.

Adaptation, Physiological↗
PubMed2006

The dependence of low-energy electron attachment to CF3Br on electron and vibrational energy.

In a joint experimental and theoretical effort, we have studied dissociative electron attachment (DEA) to the CF3Br molecule at electron energies below 2 eV. Using two variants of the laser photoelectron attachment method with a thermal gas target (T(G) = 300 K), we measured the energy dependent yield for Br- formation over the range E = 3-1200 meV with resolutions of about 3 meV (E < 200 meV) and 35 meV. At the onsets for excitation of one and two quanta for the C-Br stretching mode nu3, downward cusps are detected. With reference to the recommended thermal (300 K) attachment rate coefficient k(A)(CF3Br) = 1.4 x 10(-8) cm3 s(-1), absolute cross sections have been determined for Br- formation. In addition, we studied Br- and (CF3Br)Br- formations with a seeded supersonic target beam (10% CF3Br in helium carrier gas, with a stagnation pressure of 1-4 bars and nozzle temperatures of 300 and 600 K) and found prominent structure in the anion yields due to cluster formation. Using the microwave pulse radiolysis swarm technique, allowing for controlled variation of the electron temperature by microwave heating, we studied the dependence of the absolute DEA rate coefficient on the mean electron energy E over the range of 0.04-2 eV at gas temperatures T(G) ranging from 173 to 600 K. For comparison with the experimental results, semiempirical resonance R-matrix calculations have been carried out. The input for the theory includes the known energetic and structural parameters of the neutral molecule and its anion; the parameters of the resonant anion curves are chosen with reference to the known thermal rate coefficient for the DEA process. For the gas temperature T(G) = 300 K, good overall agreement of the theoretical DEA cross section with the experimental results is observed; moreover, rate coefficients for Br- formation due to Rydberg electron transfer, calculated with both the experimental and the theoretical DEA cross sections, are found to agree with the previously reported absolute experimental values. At T(G) = 300 K, satisfactory agreement is also found between the calculated and experimental attachment rate coefficients for mean electron energies E = 0.04-2 eV. The strong increase of the measured rate coefficients with rising gas temperature, however, could be only partially recovered by the R-matrix results. The differences may result from the influence of thermal excitations of other vibrational modes not included in the theory.

Journal Article↗
PubMed2006

[Imaging follow-up of post-traumatic myelomalacia].

The authors report a case of secondary worsening of neurological symptoms in a patient 2 months after cord injury at T5 causing paraplegia. The MRI showed myeolomalacia, which appears as cord oedema, located in the grey matter, extending increasingly from the initial lesion (eighth thoracic vertebra) to the bulb. This cord lesion known as grey matter cytotoxic oedema, evolved into a syringomyelic cavity.

Adult↗
PubMed2006

Bupropion augmentation in the treatment of chronic fatigue syndrome with coexistent major depression episode.

While psychoeducational strategies and general support are always indicated for the treatment of chronic fatigue syndrome (CFS), pharmacological strategies are yet not well established. Antidepressants such as selective serotonin re-uptake inhibitors have been shown to influence positively symptoms and immunological parameters. However, a considerable part of CFS patients do not satisfactorily respond to them. Bupropion, a centrally acting catecholamine-transporter blocker without classic psycho-analeptic properties, shows theoretical potential to improve fatigue symptoms. In the reported case paroxetine was augmented with bupropion at high dosage, a strategy which consecutively led to a rapid relief of CFS-symptoms.

Adult↗
PubMed2006

Aldehyde oxidase and its contribution to the metabolism of a structurally novel, functionally selective GABAA alpha5-subtype inverse agonist.

(3-Tert-butyl-7-(5-methylisoxazol-3-yl)-2-(1-methyl-1H-1,2,4-triazol-5-ylmethoxy)pyrazolo[1,5-d] [1,2,4]triazine was recently identified as a functionally selective, inverse agonist at the benzodiazepine site of GABA(A) alpha5-containing receptors, which enhances performance in animal models of cognition. The routes of metabolism of this compound in rat, dog, rhesus monkey and human in vitro systems, and in vivo in rat, dog and rhesus monkey have been characterized. The current study demonstrates that both a cytosolic oxidative reaction and cytochrome P450 play important roles in the metabolism of the compound. Chemical inhibition studies showed the oxidation in human cytosol to be catalysed predominantly by aldehyde oxidase rather than the related enzyme, xanthine oxidase. The aldehyde oxidase-mediated metabolites were present in vitro and in vivo in both rat and rhesus monkey, and also in vitro in man. They were absent both in vitro and in vivo in dog.

Aldehyde Oxidase↗
PubMed2006

Predictive value of serum globulin levels for the extent of hepatic fibrosis in patients with chronic hepatitis B infection.

The mechanism underlying disease progression in hepatitis B virus (HBV) infection is unknown. Immunoglobulins stimulate the proliferative activity of rat hepatic stellate cells in vitro. A strong association was found between serum immunoglobulin levels and hepatic fibrosis in patients with hepatitis C virus infection. Our objective was to determine if the same index could also be used in patients with chronic HBV infection. The records of 100 patients with biochemical, serological, virological and histological evidence of chronic HBV infection were reviewed for background factors and serum globulin and immunoglobulin levels. Mean (+/-SD) patient age was 44.0 +/- 14.7 years; 80 (80%) were male. Of the factors found to be significant on univariate analysis, the only significant predictors of severe hepatic fibrosis (stage > or = 2) on multivariate analysis were serum globulin level [odds ratio (OR) 5.97, 95% confidence intervals (CI) 1.82-19.53, P = 0.0004], platelet count (OR 0.98, CI 0.97-0.99, P = 0.001), and immunoglobulin G (IgG) level (OR 1.003, CI 1.000-1.007, P < 0.042) but not IgA, alkaline phosphatase, albumin or international normalized ratio. For each increase of 0.33 mg/dL in serum globulin, there was a 0.5 point increase in the stage of hepatic fibrosis. There appears to be a strong association between levels of serum globulin and IgG and extent of hepatic fibrosis in patients with chronic HBV infection. They can serve as noninvasive markers of hepatic fibrosis and, if confirmed, have important implications for the management of patients with chronic HBV infection.

Adult↗
PubMed2006

Investigation of prion removal/inactivation from chromatographic gel.

BACKGROUND AND OBJECTIVES: Concerns about the potential for prions to be retained on chromatography gels during the manufacture of plasma products prompted development of an investigational strategy for detecting infectious prions bound to gels. The objective was to firstly examine methods of implanting gels intracerebrally (IC) in mice, then to examine prion cleaning from a scaled-down version of the DEAE Sepharose column used in a production process to fractionate immunoglobulins and albumin from human plasma. MATERIALS AND METHODS: The study consisted of two parts: (i) the pathophysiological impact by IC inoculation of ground gel beads was compared to whole gel beads; (ii) the feedstreams to two DEAE Sepharose columns were spiked with scrapie ME7. One column was subjected to the protein loading and elution portions of the chromatography cycle. The other column was subjected to the full cycle of protein loading and elution, followed by regeneration with 0.5 m NaCl, 1 m NaOH and solvent/detergent washes. The gels were unpacked and bioassayed by IC implantation in mice to quantify infectivity. RESULTS: IC inoculation of ground gel beads resulted in unacceptably high pathological impact in the mice whereas whole gel bead inoculation resulted in a reduced affect. Accordingly, the whole bead model system was used to assess prion removal/inactivation from chromatography gels at the pre- and postcleaning stage of the chromatography cycle. Infectious prions were detected on the DEAE Sepharose prior to the cleaning step; however, the gel cleaning cycle reduced infectivity by a log reduction factor (LRF) of > or = 2.75, thus reducing infectivity by bioassay to below detectable limits. CONCLUSIONS: A model system for assessment of prion inactivation/removal from chromatography gels has been established. Spiked prion infectivity does bind to DEAE Sepharose gel; however, the cleaning cycle removed infectivity to levels below that detectable by bioassay.

Adsorption↗
PubMed2006

Sacral colpopexy with concurrent Burch colposuspension in patients with vaginal vault prolapse.

INTRODUCTION: Abdominal sacral colpopexy (SC) is one option in the management of vaginal vault prolapse. In patients who are additionally incontinent an anti-incontinence procedure such as a Burch colposuspension or pubovaginal sling is usually performed at the same time. For those patients undergoing SC who are continent there are no clear guidelines for the use of a 'prophylactic' anti-incontinence procedure. We describe our experience with SC and concurrent Burch colposuspension. PATIENTS AND METHODS: 47 patients (mean age 65 years) underwent SC and concurrent Burch colposuspension. The preoperative diagnostic check-up included a validated questionnaire, clinical examination, urodynamic tests, ultrasound and colpocystorectography. Patients were also evaluated using Stress, Emptying, Anatomic, Protection and Instability (SEAPI) scores. All patients had a uterine or vaginal vault prolapse in combination with a cystocele, enterocele or rectocele. Thirty-three of 47 (70%) patients were continent and 14 (30%) incontinent. Nineteen (40%) of the 33 'continent' patients were found to have occult incontinence. Clinical examination according to the Halfway system showed 9 of 47 (19%), 21 of 47 (45%) and 17 of 47 (36%) patients with grade 2, 3 and 4 vaginal vault prolapse, respectively. Thirty-five of 47 (74%) patients demonstrated a grade-4 cystocele and 12 of 47 (26%) a grade-3 cystocele. The mean follow-up was 34 months and included a questionnaire (SEAPI), clinical examination and ultrasound. RESULTS: Postoperative SEAPI scores showed a statistically significant improvement in all SEAPI domains (p < 0.001). Ninety-four percent of the patients were satisfied, continent and would undergo the surgery again. Three patients were incontinent. No continent patient who underwent concurrent Burch colposuspension had obstructive symptoms or residual urine. Five patients (11%) who had dyspareunia preoperatively were free of this symptom postoperatively. Complications were: dilatation of the upper urinary tract in 2 patients (4%) secondary to distal ureteric deviation by suturing the posterior peritoneum. One patient underwent psoas hitch neoureterocystostomy and 1 patient was successfully treated by insertion of a ureteric stent for 6 weeks. One patient (2%) had a mesh infection necessitating removal of the Gore-Tex mesh. CONCLUSIONS: Sacral colpopexy provides good patient satisfaction, durable pelvic support and restores vaginal function. Due to excellent continence rates concurrent Burch colposuspension should be considered as a joint procedure even in continent patients.

Aged↗
PubMed2006

[Effects of the zinc oxide and cod liver oil containing ointment Zincojecol in an animal model of wound healing].

The effects of Zincojecol an ointment containing zinc oxide and cod liver oil on wound healing were compared with ointments that either contained no active ingredients or zinc oxide or cod liver oil alone. All formulations enhanced the epidermal proliferation after mechanical irritation of the tail skin. The combination of zinc oxide and cod liver oil was found to be superior to the vehicle control and formulations containing only one active ingredient. This combination was also found to be most efficient in accelerating wound healing being retarded by repeated dexamethasone treatment.

Animals↗
PubMed2005

Detection of bovine viral diarrhea virus (BVDV) in seropositive cattle.

Detection of bovine virus diarrhoea virus (BVDV) in one vaccinated beef cattle and three non-vaccinated dairy herds was investigated on peripheral blood leukocytes (PBL) with or without previous treatment followed by a capture ELISA (cELISA). Using the combination of PHA and polycation treatment, PBL from 229 seropositive cattle were studied and could be classified in four different states of BVDV infection. Lysed PBL from four animals were directly positive in cELISA (Category I), PBL of 17 animals were positive after PHA stimulation (Category II), 15 animals were positive only after PHA stimulation plus polycation treatment (Category III), while virus could not be detected in 193 seropositive cattle. Wild-type BVDV strains were isolated by co-culture on polycation-treated MDBK cells from 11 of these seropositive animals. BVDV antibodies of these same animals were able to neutralize their own virus, indicating that virus persists in PBL in spite of strain-specific antibodies. No apparent change of leukocyte subpopulations could be detected in any category of virus-positive animals. Thus, BVDV may be present in the PBL of some cattle, even in the presence of a specific active immune response.

Animals↗
PubMed2005

Decreased levels of advanced glycation end-products in patients with Gilbert syndrome.

Oxidative stress plays an important role in the atherogenesis and bilirubin is one of the most potent antioxidant substances in human body. The aim of the present study was to investigate the impact of hyperbilirubinemia on plasma levels of advanced glycation end-products (AGEs), which contribute to atherogenesis. Two AGEs, pentosidine and Nepsilon-carboxymethyl lysine (CML), were determined in 23 subjects with Gilbert syndrome (GS) and in 21 age-matched healthy controls. Pentosidine was assessed by HPLC and CML was determined with ELISA. Logistic regression analysis was used for multiple adjustments of possible modifying factors. As expected, significantly higher serum bilirubin levels were found in GS subjects as compared to controls (28.9 +/- 9.6 vs 9.7 +/- 2.7 micromol/l, p<0.001). In contrast, serum levels of both AGEs were significantly lower in GS compared to normobilirubinemic controls (median; 25%-75% interquartile range (pentosidine: 1.12; 0.90-1.28 vs 1.31; 1.18-1.58 nmol/g protein, p<0.005; and CML: 6.70; 6.10-7.34 vs 7.33; 6.76-8.20 micromol/g protein, p = 0.01, respectively). Levels of both AGEs remained substantially lower even after adjustment for selected vascular risk and other modifying factors. In subjects with GS elevated serum bilirubin concentrations are associated with lower levels of AGEs. These results are in support of previous data on antioxidant properties of bilirubin.

Bilirubin↗
PubMed2005

Emotion recognition in stroke patients with left and right hemispheric lesion: results with a new instrument-the FEEL Test.

The aim of this study was to investigate the effect of a stroke event on people's ability to recognize basic emotions. In particular, the hypothesis that right brain-damaged (RBD) patients would show less of emotion recognition ability compared with left brain-damaged (LBD) patients and healthy controls, was tested. To investigate this the FEEL Test (Facially Expressed Emotion Labeling) was used, a computer based psychometric test that assesses one's ability to recognize facially displayed basic emotions via a forced-choice paradigm. We examined 24 patients after a stroke event (13 RBD, 11 LBD) and compared them with a matched group of healthy controls (HC, n=29). Results showed that the stroke patients performed significantly worse in the FEEL Test than did HC (p<.001). This deficit was especially evident for negative emotions (fear, anger, sadness, and disgust). In contrast to other studies we did not find any significant differences between RBD and LBD patients in their ability to recognize emotions. These results indicate that a stroke event has a negative effect on the recognition of facially displayed emotions but suggest that this effect is apparently not dependent on the side of the brain damage.

Adult↗
PubMed2005

Excited-state dynamics of bacteriorhodopsin probed by broadband femtosecond fluorescence spectroscopy.

The impact of varying excitation densities (approximately 0.3 to approximately 40 photons per molecule) on the ultrafast fluorescence dynamics of bacteriorhodopsin has been studied in a wide spectral range (630-900 nm). For low excitation densities, the fluorescence dynamics can be approximated biexponentially with time constants of <0.15 and approximately 0.45 ps. The spectrum associated with the fastest time constant peaks at 650 nm, while the 0.45 ps component is most prominent at 750 nm. Superimposed on these kinetics is a shift of the fluorescence maximum with time (dynamic Stokes shift). Higher excitation densities alter the time constants and their amplitudes. These changes are assigned to multi-photon absorptions.

Bacteriorhodopsins↗
PubMed2005

[Risks and responsibilities in diagnostic and interventional radiology. Ethical and medicolegal considerations].

Medical risk management has one main purpose: to ensure the safety of care. The law of March 2002 has generated a true cultural revolution. The radiologist is involved with new and difficult areas of medical liability due to technical advances, the increasing number of imaging techniques, the increasing complexity of imaging techniques, their efficiency and the need for multidisciplinary approach. Imaging recommendations requiring increasing levels of technical and clinical skills. The radiologist is liable with regards to the indications of imaging studies, and also with regards to informed consent. The prevention of medicolegal problems is achieved by competency, which must be combined to good liability insurance and ongoing vigilance supported by appropriate continuous medical education.

France↗