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1.
Sci Rep ; 13(1): 9425, 2023 Jun 09.
Article in English | MEDLINE | ID: mdl-37296305

ABSTRACT

Subsea permafrost carbon pools below the Arctic shelf seas are a major unknown in the global carbon cycle. We combine a numerical model of sedimentation and permafrost evolution with simplified carbon turnover to estimate accumulation and microbial decomposition of organic matter on the pan-Arctic shelf over the past four glacial cycles. We find that Arctic shelf permafrost is a globally important long-term carbon sink storing 2822 (1518-4982) Pg OC, double the amount stored in lowland permafrost. Although currently thawing, prior microbial decomposition and organic matter aging limit decomposition rates to less than 48 Tg OC/yr (25-85) constraining emissions due to thaw and suggesting that the large permafrost shelf carbon pool is largely insensitive to thaw. We identify an urgent need to reduce uncertainty in rates of microbial decomposition of organic matter in cold and saline subaquatic environments. Large emissions of methane more likely derive from older and deeper sources than from organic matter in thawing permafrost.


Subject(s)
Permafrost , Humans , Soil , Carbon , Arctic Regions , Methane
3.
J Behav Ther Exp Psychiatry ; 57: 62-69, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28419917

ABSTRACT

BACKGROUND AND OBJECTIVES: The relationship between self-esteem and paranoia may be influenced by social stress. This study aimed to replicate previous research on the impact ofsocial exclusion on paranoia and self-esteem in a non-clinical sample and to extend this work by examining the effect of exclusion on self-esteem at the 'implicit' level. METHODS: Non-clinical participants (N = 85) were randomly allocated to the Inclusion or Exclusion condition of a virtual ball-toss game ('Cyberball'). They completed self-reportmeasures of state paranoia and self-esteem, and two implicit measures of self-esteem - theImplicit Association Task (IAT) and Implicit Relational Assessment Procedure (IRAP) -prior to and after exposure to Cyberball. RESULTS: Social exclusion increased state paranoia. This effect was moderated by distress associated with trait paranoia. Exclusion was also associated with decreased self-reported self-esteem, as well as reduced implicit self-esteem on the IAT. Changes in self-reported self-esteem were associated with state paranoia at post-Cyberball. The IRAP indicated that reductions in implicit self-esteem may be due to increases in 'Me-Negative' and 'Others-Positive' biases (rather than reductions in 'Me-Positive' bias). LIMITATIONS: The current study involved a non-clinical sample and so findings cannot be generalized to clinical paranoia. CONCLUSIONS: These findings are consistent with previous evidence that paranoia is associated with negative self-evaluations, whereas positive self-evaluations can persist in paranoia. They also provide support for the suggestion that investigations of self-esteem in paranoia should extend beyond global self-esteem and might benefit from a distinction between positive and negative components.


Subject(s)
Paranoid Disorders/psychology , Psychological Distance , Self Concept , Adolescent , Adult , Analysis of Variance , Attention , Female , Humans , Male , Personality Inventory , Psychiatric Status Rating Scales , Random Allocation , Self Report , Surveys and Questionnaires , Young Adult
4.
HNO ; 64(1): 27-33, 2016 Jan.
Article in German | MEDLINE | ID: mdl-26676521

ABSTRACT

BACKGROUND: Early detection of cancerous lesions is still crucial for a patient's prognosis. Although diagnostic access to the oral cavity and oropharynx is comparably easy, the incidence of resulting disease remains high. This is due to the fact that in many cases, malignity is recognized too late on a purely visual basis. Previously, we discussed the application of hyperspectral imaging for early detection of precancerous and cancerous lesions of the larynx. This time, we evaluate the method in the oral cavity and oropharynx. MATERIALS AND METHODS: In 85 patients scheduled for endoscopy, hyperspectral imaging was performed. We used a rigid 0-degree endoscope, a light-adjustable monochromator, and a hyperspectral camera. For evaluation of the method, 3 patients were chosen exemplarily. Training sites from physiological and cancerous tissues were marked. Hyperspectral data from 1 patient were used to train a classifier, which was then used for automatic detection of precancerous and cancerous lesions in another 2 patients. RESULTS: Intraoperative hyperspectral imaging was performed without any problems. Classification showed sensitivities of 61 and 43%, and a specificity of 100%. CONCLUSION: This proof-of-concept study underscores the high potential of hyperspectral imaging for early recognition of cancer in the mouth and oropharynx. Besides a better prognosis for cancer patients, this approach could lead to higher cost efficiency in the health system.


Subject(s)
Early Detection of Cancer/methods , Endoscopy/methods , Mouth Neoplasms/pathology , Oropharyngeal Neoplasms/pathology , Precancerous Conditions/pathology , Tomography, Optical/methods , Female , History, Ancient , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Spectrum Analysis/methods
5.
HNO ; 63(3): 215-9, 2015 Mar.
Article in German | MEDLINE | ID: mdl-25515122

ABSTRACT

BACKGROUND: Despite the controversial international debate on the use of metamizole as a standard analgesic, the prescription figures for Germany have increased constantly during recent years. However, metamizole can lead to the rare and severe medical condition called agranulocytosis. MATERIALS AND METHODS: Between January 2009 and January 2014, 5 patients with metamizole-induced agranulocytosis presented themselves at the Interdisciplinary Emergency Center of the University Clinic Bonn. According to their leading ENT symptoms, they were transferred to the otorhinolaryngological department. We retrospectively evaluated metamizole medication, all general patient data and previous diseases, as well as disease course and the respective therapies. RESULTS: Within the scope of the different treatments--surgery after trauma (n=2), elective orthopedic surgery (n=2), tonsillitis treatment (n=1)--the patients (n=5; mean age 30 years) had made regular ambulant use of metamizole for several days or weeks (4-28 days, mean 16.8 days). Daily oral dose ranged from 625 to 2000 mg/d (mean 1500 mg/d). Subsequently, patients required treatment for clinical symptoms of agranulocytosis (e.g. tonsillitis with severe odynophagia and significantly reduced general condition). All patients were monitored in an intermediate or intensive care unit (3-14 days, mean 10 days). No patients died. DISCUSSION: As our cases show, when using metamizole as a standard analgesic, the treating otolaryngologist should look for clinical symptoms of agranulocytosis and inform patients about possible adverse effects. We recommend strict indication setting, regular blood analyses during long-term medication and consideration of alternative analgesics (e.g. NSAR).


Subject(s)
Agranulocytosis/chemically induced , Agranulocytosis/diagnosis , Deglutition Disorders/chemically induced , Deglutition Disorders/diagnosis , Dipyrone/adverse effects , Tonsillitis/chemically induced , Adult , Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Diagnosis, Differential , Female , Humans , Male , Symptom Assessment/methods , Tonsillitis/diagnosis , Young Adult
6.
Laryngorhinootologie ; 92(7): 453-7, 2013 Jul.
Article in German | MEDLINE | ID: mdl-23824477

ABSTRACT

Hyperspectral Imaging has long been established in other scientific disciplines than medicine (e. g. earth science) as a means for objective classification of image data information. Some 10 years ago it was first introduced into medicine. Due to its immanent advantages - non-destructive specimen, compatibility with established optical tools (microscope, endoscope), objectivity, and user-independence - several attempts have been made in order to use its potential for the treatment of cancer patients. This publication reviews which methods have been developed for analogue issues in disciplines other than medicine, how these can be transferred into medicine, and what the perspectives are for the traditional innovative field of head-and-neck-oncology.


Subject(s)
Diagnostic Imaging/methods , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Otorhinolaryngologic Neoplasms/diagnosis , Otorhinolaryngologic Neoplasms/therapy , Spectrum Analysis/methods , Early Diagnosis , Endoscopy/methods , Humans , Microscopy/methods , Neoplasm Staging , Otorhinolaryngologic Neoplasms/pathology , Sensitivity and Specificity
7.
Phys Rev Lett ; 110(19): 196002, 2013 May 10.
Article in English | MEDLINE | ID: mdl-23705721

ABSTRACT

We present a one-to-one comparison of polymer segmental fluctuations as measured by small angle neutron scattering in a network under deformation with those obtained by neutron spin echo spectroscopy. This allows an independent proof of the strain dependence of the chain entanglement length. The experimentally observed nonaffine square-root dependence of the tube channel on strain is in excellent agreement with theoretical predictions and permits us to exclude an often invoked nondeformed as well as affinely deformed tube.

8.
Equine Vet J ; 45(5): 637-41, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23294196

ABSTRACT

REASONS FOR PERFORMING STUDY: Current literature suggests that thermographic imaging of horses should be performed in a draught-free room. However, studies on the effect of airflow on determined temperature have not been published. OBJECTIVES: To investigate effects of airflow on thermographically determined temperature of horses' forelimbs; to assess the relationship of wind velocity, rectal temperature, ambient temperature and humidity. METHODS: Thermographic images were obtained for the forelimbs of 6 horses in a draught-free room. Three replicates (R) with defined wind velocities (R1, 0.5-1.0 m/s; R2, 1.3-2.6 m/s; and R3, 3.0-4.0 m/s) were conducted. Each replicate consisted of a baseline image, a 15 min phase with the wind on and a 15 min phase with the wind off. We exposed only the right leg to airflow and determined the temperature by thermography with the wind on and wind off. Temperature differences between baseline and wind on, between wind on and wind off and between different wind velocities were analysed by a general linear model, Student's paired t test and ANOVA. RESULTS: After the onset of wind, the temperature on the right forelimb decreased within 1-3 min (by approximately 0.6°C at R1, 1.5°C at R2 and 2.1°C at R3). With the wind off, the temperature increased within 3 min (by approximately 1.2°C at R1, 1.7°C at R2 and 2.1°C at R3). With increasing wind velocity, the temperature differences between baseline and wind on and between wind on and wind off increased significantly. CONCLUSIONS: Barely noticeable wind velocities caused a decrease in thermographically determined temperatures of the forelimbs of the horse. Further research is required to assess the influence of airflow on other parts of the body and at different ambient temperatures, as well as the effect on horses with inflammatory lesions, especially of the distal limbs. POTENTIAL RELEVANCE: It is essential for practitioners to perform thermography on horses in a draught-free environment in order to avoid false-positive or -negative diagnoses.


Subject(s)
Air Movements , Body Temperature/physiology , Forelimb/physiology , Horses/physiology , Thermography/veterinary , Animals , Female , Male
9.
Theriogenology ; 74(7): 1248-55, 2010 Oct 15.
Article in English | MEDLINE | ID: mdl-20615532

ABSTRACT

Clinical endometritis in dairy cows is defined as mucopurulent or purulent vulvar discharge 21 days or more after parturition. The diagnosis of clinical endometritis is commonly based on vaginal examination. Techniques to reduce the proportions of false negative findings have been described. This paper discusses a clinical approach to determine the proportion of false positive findings that might occur by vaginal inspection. The consequences of false positive findings in dairy practice are unnecessary or inadequate treatments. In research, incorrect diagnoses have an impact on the interpretation of studies on the diagnosis and treatment of clinical endometritis. The objective of the present study was to compare intrauterine bacteriology and endometrial cytology in cows diagnosed with clinical endometritis with findings obtained by vaginoscopy. Clinical endometritis was defined as mucopurulent or purulent vulvar discharge. On two commercial dairy farms, cows were examined 21 to 28 d postpartum. Uterine samples (n = 230) were collected from cows with clinical endometritis with the cytobrush technique to determine the proportion of polymorphonuclear neutrophils (PMN) and to culture smears for aerobic bacteria. Two threshold values for the proportion of PMN (5 and 18%) were chosen as possible indicators for an inflamed endometrium. Common uterine pathogens A. pyogenes and E. coli were found in 33.5 and 10.4% of the samples, respectively. With increasing vaginal discharge score, proportion of samples positive for A. pyogenes increased significantly. The proportion of cows exceeding the thresholds for PMN increased with vaginal discharge score and the presence of A. pyogenes. Considering only the presence of aerobic uterine pathogens and a proportion of PMN above the threshold values of 5 and 18% as indicative for endometritis, a proportion of 17.3 and 28.5%, respectively, of diagnoses by vaginoscopy were false positive.


Subject(s)
Cattle Diseases/diagnosis , Endometritis/veterinary , Uterus/cytology , Uterus/microbiology , Animals , Cattle , Cattle Diseases/microbiology , Endometritis/diagnosis , Endometritis/microbiology , False Positive Reactions , Female , Vaginal Discharge/microbiology , Vaginal Discharge/veterinary
10.
Anim Reprod Sci ; 121(1-2): 55-62, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20483550

ABSTRACT

The objective of the study was to compare the systemic antibiotic treatment of clinical endometritis in dairy cows with ceftiofur with a treatment protocol consisting of two doses of prostaglandin F(2alpha) analogue cloprostenol in a 14-d interval. On 2 commercial dairy farms, housing a total of 1900 Holstein cows, all cows that calved between June 2008 and January 2009 were examined 21-27d in milk (DIM) by vaginoscopy. Cows with clinical signs of endometritis, i.e. vaginal discharge containing flecks of pus, mucopurulent material or purulent mucus, were randomly allocated to one of two treatment groups. Cows in group CEF (n=141) received 1 mg/kg BW of ceftiofur (i.m.) on 3 consecutive days. Cows in group CLP (n=140) received 0.5 mg of cloprostenol (i.m.) at the day of enrolment and 14d later. All cows were re-examined by vaginoscopy 42-48 DIM. Proportion of cows cured, i.e. cows with clear, translucent or no mucus, 42-48 DIM (74.2 and 80.2% in groups CEF and CLP, respectively) was not affected by treatment group (P=0.09). The voluntary waiting period was set at 40 DIM. Artificial insemination (AI) submission rate, days to first service, first service conception rate, days open and proportion of cows pregnant did not differ between the groups. In conclusion, the systemic treatment with 1.0 mg/kg BW of ceftiofur on 3 consecutive days in cows with signs of clinical endometritis 21-27 DIM was equivalent to an intervention protocol consisting of two doses of cloprostenol in a 14-d interval.


Subject(s)
Cattle Diseases/drug therapy , Cephalosporins/administration & dosage , Cloprostenol/administration & dosage , Endometritis/drug therapy , Animals , Anti-Bacterial Agents/administration & dosage , Cattle , Dairying , Drug Administration Schedule , Endometritis/veterinary , Female , Injections, Intramuscular , Insemination, Artificial/veterinary , Luteolytic Agents/administration & dosage , Pregnancy , Pregnancy Rate , Reproduction/drug effects , Reproduction/physiology
11.
Proc Natl Acad Sci U S A ; 105(19): 6918-23, 2008 May 13.
Article in English | MEDLINE | ID: mdl-18460602

ABSTRACT

Mitotic chromosomes segregate at the ends of shortening spindle microtubules (MTs). In budding yeast, the Dam1 multiprotein complex supports this dynamic attachment, thereby contributing to accurate chromosome segregation. Purified Dam1 will track the end of a depolymerizing MT and can couple it to microbead transport in vitro. The processivity of such motions has been thought to depend on rings that the Dam1 complex can form around MTs, but the possibility that alternative coupling geometries contribute to these motilities has not been considered. Here, we demonstrate that both rings and nonencircling Dam1 oligomers can track MT ends and enable processive cargo movement in vitro. The coupling properties of these two assemblies are, however, quite different, so each may make a distinct contribution to chromosome motility.


Subject(s)
Cell Cycle Proteins/metabolism , Microtubule-Associated Proteins/metabolism , Microtubules/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Animals , Biological Transport , Cell Polarity , Chlamydomonas , Diffusion , Microspheres , Molecular Weight , Protein Structure, Quaternary , Protein Subunits/metabolism , Saccharomyces cerevisiae/cytology , Solubility , Solutions , Tetrahymena
12.
Eur Surg Res ; 39(6): 325-31, 2007.
Article in English | MEDLINE | ID: mdl-17622730

ABSTRACT

BACKGROUND/AIM: The aim of the study was to characterize the hepatic injury (HI) of the nonischemic liver lobe after selective portal triad clamping and investigate the influence of pharmacological pretreatment with alpha-lipoic acid (LA). METHODS: Brown-Norway rats received 500 micromol LA injected via the inferior vena cava 15 min prior to the induction of 90 min of selective ischemia. Another group of rats received vehicle prior to ischemia. Both groups were compared with sham-operated animals. RESULTS: Lipid peroxidation (LPO) was increased in the ischemic as well as in the nonischemic liver tissue (NIL) in the untreated group. Levels of adenosine triphosphate and reduced glutathione content of the nonischemic liver lobe were decreased in the untreated group 1 h after reperfusion. Activity of caspases 3 and 8 was not detectable, whereas expression of the Bax protein was demonstrated in the NIL. We observed areas of necrotic hepatocytes and large gaps of sinusoids in the NIL of the untreated rats. LA attenuated LPO as well as Bax expression in the NIL. Moreover adenosine triphosphate and glutathione content of the NIL was increased 1 h after reperfusion by LA. LA pretreatment reduced release of alpha-glutathione-s-transferase in plasma. Histology of the nonischemic liver lobe did not markedly differ from sham-operated animals after LA pretreatment. CONCLUSION: HI of the NIL seems to be mediated by LPO and proapoptotic proteins such as Bax. Besides its described potential to reduce ischemia/reperfusion injury of the ischemic lobe, LA attenuates HI of the nonischemic tissue after selective portal triad clamping.


Subject(s)
Antioxidants/pharmacology , Ischemia/complications , Liver Diseases/prevention & control , Liver/drug effects , Thioctic Acid/pharmacology , Animals , Antioxidants/therapeutic use , Constriction , Disease Models, Animal , Lipid Peroxidation/drug effects , Liver/blood supply , Liver Diseases/etiology , Male , Rats , Reperfusion Injury/etiology , Reperfusion Injury/prevention & control , Thioctic Acid/therapeutic use
13.
Phys Rev Lett ; 98(2): 023004, 2007 Jan 12.
Article in English | MEDLINE | ID: mdl-17358604

ABSTRACT

We present time-resolved spectroscopic measurements of Rydberg-Rydberg interactions between two Rydberg atoms in an ultracold gas, revealing the pair dynamics induced by long-range van der Waals interactions between the atoms. By detuning the excitation laser, a specific pair distribution is prepared. Penning ionization on a microsecond time scale serves as a probe for the pair dynamics under the influence of the attractive long-range forces. Comparison with a Monte Carlo model not only explains all spectroscopic features but also gives quantitative information about the interaction potentials. The results imply that the interaction-induced ionization rate can be influenced by the excitation laser. Surprisingly, interaction-induced ionization is also observed for Rydberg states with purely repulsive interactions.

14.
J Invest Surg ; 18(6): 305-13, 2005.
Article in English | MEDLINE | ID: mdl-16319051

ABSTRACT

A large animal model was established to investigate the feasibility and suitable dosage of intraoperative radiation therapy (IORT) to the hepatic hilum before biliary-enteric anastomosis is performed. Twenty-two Pietrain Hampshire pigs underwent gallbladder and proximal bile duct resection followed by IORT using 20-40 Gy and performing biliary-enteric anastomosis. In the follow-up period of 56 days, pigs developed dose-dependent complications like stenosis of the biliary-enteric anastomosis. Results demonstrate that IORT of the liver hilum up to 20 Gy is safe with acceptable early complications in the presented animal model. The porcine biliary-enteric anastomosis can tolerate intraoperative irradiation up to a dosage of 40 Gy without disruption.


Subject(s)
Anastomosis, Roux-en-Y , Brachytherapy , Hepatic Duct, Common/radiation effects , Hepatic Duct, Common/surgery , Intraoperative Care , Jejunum/radiation effects , Jejunum/surgery , Anastomosis, Roux-en-Y/adverse effects , Animals , Bilirubin/blood , Dose-Response Relationship, Radiation , Female , Hepatic Duct, Common/pathology , Jejunum/pathology , Liver/enzymology , Magnetic Resonance Imaging , Postoperative Complications/veterinary , Swine
15.
Audiology ; 40(3): 148-57, 2001.
Article in English | MEDLINE | ID: mdl-11465297

ABSTRACT

Current standards involving technical specification of hearing aids provide limited possibilities for assessing the influence of the spectral and temporal characteristics of the input signal, and these characteristics have a significant effect on the output signal of many recent types of hearing aids. This is particularly true of digital hearing instruments, which typically include non-linear amplification in multiple channels. Furthermore, these instruments often incorporate additional non-linear functions such as "noise reduction" and "feedback cancellation". The output signal produced by a non-linear hearing instrument relates to the characteristics of the input signal in a complex manner. Therefore, the choice of input signal significantly influences the outcome of any acoustic or psychophysical assessment of a non-linear hearing instrument. For this reason, the International Collegium for Rehabilitative Audiology (ICRA) has introduced a collection of noise signals that can be used for hearing aid testing (including real-ear measurements) and psychophysical evaluation. This paper describes the design criteria, the realisation process, and the final selection of nine test signals on a CD. Also, the spectral and temporal characteristics of these signals are documented. The ICRA noises provide a well-specified set of speech-like noises with spectra shaped according to gender and vocal effort, and with different amounts of speech modulation simulating one or more speakers. These noises can be applied as well-specified background noise in psychophysical experiments. They can also serve as test signals for the evaluation of digital hearing aids with noise reduction. It is demonstrated that the ICRA noises show the effectiveness of the noise reduction schemes. Based on these initial measurements, some initial steps are proposed to develop a standard method of technical specification of noise reduction based on the modulation characteristics. For this purpose, the sensitivity of different noise reduction schemes is compared by measurements with ICRA noises with a varying ratio between unmodulated and modulated test signals: a modulated-unmodulated ratio. It can be anticipated that this information is important to understand the differences between the different implementations of noise reduction schemes in different hearing aid models and makes.


Subject(s)
Hearing Aids , Noise , Speech, Alaryngeal , Acoustic Stimulation , Female , Humans , Male , Phonation
16.
World J Surg ; 25(4): 432-7, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11344393

ABSTRACT

Temporary obliteration of the pancreatic duct has been suggested to be beneficial in chronic pancreatitis, segmental pancreatic transplantation, and following Roux-Y pancreaticojejunostomy. Little is known, however, as to whether obliteration of the duct alters exocrine pancreatic physiology. Therefore we studied in male inbred Lewis rats the immediate effects of Ethibloc-induced duct obliteration (Ethibloc: Ethicon, Norderstedt, Germany) on pancreatic microcirculation, inflammation, and tissue injury (n = 8), and compared these effects with those caused by experimental pancreatitis (4% sodium taurocholate; n = 8). Animals receiving an intraductal infusion of saline served as controls (n = 8). Duct occlusion with Ethibloc resulted in a marked decrease (p < 0.05) in capillary red blood cell (RBC) velocity and functional capillary density (FCD) to 88 +/- 39 microm/s (baseline 716 +/- 40 microm/s) and 72 +/- 33 cm(-1) (baseline 493 +/- 21 cm(-1)), respectively, which was even more pronounced when compared with that observed in experimental pancreatitis (333 +/- 62 microm/s and 195 +/- 44 cm(-1), respectively). In parallel, the manifestation of tissue damage was found to be more severe after Ethibloc; and chloracetate esterase staining showed a larger number of infiltrating leukocytes [555 +/- 86/high power field (HPF) versus pancreatitis: 160 +/- 12/HPF; p < 0.05). We conclude that intraductal application of Ethibloc induces significant microcirculatory failure and a marked inflammatory response, which are even more pronounced when compared with the changes observed with experimental pancreatitis. Based on these results and the fact that there is no direct proof for a benefit of temporary duct occlusion by Ethibloc, it is proposed that the procedure be reevaluated for its use in pancreatic surgery.


Subject(s)
Diatrizoate/pharmacology , Fatty Acids/pharmacology , Pancreas/blood supply , Pancreatitis/pathology , Pancreatitis/surgery , Propylene Glycols/pharmacology , Sclerosing Solutions/pharmacology , Zein/pharmacology , Animals , Diatrizoate/therapeutic use , Drug Combinations , Fatty Acids/therapeutic use , Male , Microcirculation/drug effects , Necrosis , Pancreas/pathology , Pancreatic Ducts , Pancreatitis/drug therapy , Propylene Glycols/therapeutic use , Rats , Rats, Inbred Lew , Sclerosing Solutions/therapeutic use , Zein/therapeutic use
17.
Biochim Biophys Acta ; 1492(2-3): 483-7, 2000 Jul 24.
Article in English | MEDLINE | ID: mdl-10899586

ABSTRACT

We report the isolation, cloning and recombinant expression of a Trypanosoma brucei homolog of the La RNA-binding protein. Based on peptide sequence information we have isolated a cDNA clone which encodes a protein of 335 amino acids with a predicted molecular weight of 37.7 kDa. The amino acid sequence fits the domain structure of known La proteins and contains a putative ATP-binding site located in the COOH-terminal domain. The cDNA was expressed as a glutathione S-transferase fusion protein in Escherichia coli, and the recombinant protein displayed RNA-binding activity in an electrophoretic mobility shift assay.


Subject(s)
Autoantigens/genetics , Protozoan Proteins/genetics , Ribonucleoproteins/genetics , Trypanosoma brucei brucei/genetics , Amino Acid Sequence , Animals , Autoantigens/chemistry , Base Sequence , Cloning, Molecular , DNA, Complementary/analysis , DNA, Protozoan , Gene Expression , Molecular Sequence Data , Protein Conformation , Protozoan Proteins/chemistry , RNA-Binding Proteins/genetics , Recombinant Proteins/biosynthesis , Ribonucleoproteins/chemistry , Sequence Homology, Amino Acid , Transfection , SS-B Antigen
18.
Surgery ; 126(5): 881-9, 1999 11.
Article in English | MEDLINE | ID: mdl-10568188

ABSTRACT

BACKGROUND: Surface cooling is frequently used in a number of conditions, especially traumatic, ischemic, burn, and neurologic injury to reduce the tissue damage. However, the protective mechanisms of cold therapy on traumatized tissues remain unclear. Tumor necrosis factor-alpha (TNF-alpha) is a fundamental mediator in inflammatory reactions and trauma-induced tissue injury. In the present study, we examined the microvascular response to TNF-alpha challenge and the effects of local cooling on the TNF-alpha-induced changes in the striated muscle of hamsters. METHODS: By the use of the dorsal skinfold chamber preparation and in vivo fluorescence microscopy in combination with computer-based image analysis, we determined TNF-alpha-induced leukocyte rolling and adhesion to microvascular endothelium, capillary perfusion, venular leakage, and cellular apoptosis with and without surface cooling. RESULTS: We found that topical administration of 2000 units TNF-alpha caused a progressive impairment of microvascular perfusion and increased leukocyte recruitment and vascular macromolecular leakage. Local cooling to 10 degrees C for 60 minutes markedly (P < .05) inhibited the TNF-alpha-induced capillary perfusion failure and leukocyte response and slightly attenuated the increase of microvascular permeability after 180 minutes of stimulation. Furthermore, it was observed that 24 hours of TNF-alpha stimulation increased the number of apoptotic cells (i.e., nuclear condensation and fragmentation) by 10-fold. This TNF-alpha-mediated effect was almost abolished by treatment with local hypothermia. CONCLUSION: These data suggest that the protective effect of surface cooling of traumatized tissue is due to its attenuation of the microvascular inflammatory response associated with the inhibition of the process of apoptosis.


Subject(s)
Apoptosis/drug effects , Cold Temperature , Leukocytes/physiology , Muscle, Skeletal/blood supply , Tumor Necrosis Factor-alpha/pharmacology , Animals , Cell Adhesion/drug effects , Cell Adhesion/physiology , Cricetinae , Endothelium, Vascular/physiology , Mesocricetus , Microcirculation/drug effects , Tumor Necrosis Factor-alpha/antagonists & inhibitors
19.
FEBS Lett ; 459(1): 90-4, 1999 Oct 01.
Article in English | MEDLINE | ID: mdl-10508923

ABSTRACT

The minimal sequence requirement of Crithidia tubulin polyglutamylase is already fulfilled by tubulin-related peptides carrying a free alpha-carboxylate on a glutamic acid residue. Since the product of each glutamylation step fulfills the substrate requirements necessary for the next cycle, very long side chains are generated with brain tubulin as a substrate. Up to 70 mol of glutamic acid was incorporated per alphabeta-heterodimer. We speculate that the strict choice of a particular glutamate residue for the formation of the isopeptide bond initiating a novel side chain is made by a tubulin monoglutamylase which requires the entire tubulin as substrate.


Subject(s)
Crithidia fasciculata/enzymology , Polyglutamic Acid/metabolism , Tubulin/metabolism , Amino Acid Sequence , Animals , Brain/metabolism , Immunoblotting , Molecular Sequence Data , Peptide Synthases , Peptides/chemical synthesis , Peptides/metabolism , Sequence Homology, Amino Acid , Substrate Specificity , Tubulin/chemical synthesis
20.
J Surg Res ; 85(2): 301-10, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10423333

ABSTRACT

Using in vivo microscopy red blood cell (RBC) velocities, functional capillary density (FCD) and capillary diameters were estimated after inducing acute pancreatitis by intraductal infusion of sodium taurocholate (0.8 ml; 4%) or after topical superfusion of the pancreas with ET-1 (100 pmol). Sodium taurocholate mediated a significant decrease in RBC velocities between 50 and 70%, transient decrease in capillary diameters by 10%, and a sustained decrease in FCD between 60 and 70% paralleled by a dramatic heterogeneity in blood flow. Topical superfusion of the exteriorized pancreas with ET-1 caused a significant decrease in RBC velocities between 65 and 75%, a sustained decrease in capillary diameters by 10%, and a decrease in FCD by 45% accompanied by an increase in flow heterogeneity. Following sodium taurocholate infusion pancreas histology revealed a severe edema and sublobular acinar cell necrosis, while topical ET-1 application displayed a severe edema of the pancreas with focal acinar cell necrosis. Thus, ET-1 mediated a deterioration of the pancreatic microcirculation, which is similar to the microcirculatory failure found in sodium taurocholate-induced experimental pancreatitis and was associated with focal acinar cell necrosis. We are thus inclined to hypothesize that endothelin released by injured endothelial cells during acute biliary pancreatitis promotes microcirculatory failure and ischemia in acute pancreatitis, eventually leading to acinar cell necrosis.


Subject(s)
Endothelin-1/pharmacology , Microcirculation/drug effects , Pancreas/drug effects , Pancreatitis/physiopathology , Acute Disease , Administration, Topical , Animals , Blood Flow Velocity/drug effects , Capillaries/drug effects , Endothelin-1/administration & dosage , Male , Pancreas/blood supply , Pancreas/pathology , Pancreatitis/chemically induced , Rats , Rats, Inbred Lew , Regional Blood Flow/drug effects , Taurocholic Acid/pharmacology
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