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Berry AJ, Smith RB, Weintraub WS, Chaikof EL, Dodson TF, Lumsden AB, Salam AA, Weiss V, Konigsberg S. Age versus comorbidities as risk factors for complications after elective abdominal aortic reconstructive surgery. J Vasc Surg 2001; 33:345-52. [PMID: 11174788 DOI: 10.1067/mva.2001.111737] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE This study estimated the association between age and in-hospital postoperative complications, controlling for known or suspected risk factors, in a series of patients undergoing elective abdominal aortic reconstructive surgery (AAR). METHODS This retrospective cohort study of outcome data with multivariate logistic regression analysis was conducted at Emory University Hospital, a tertiary care, university-affiliated hospital. All patients undergoing elective AAR between Jan 1, 1986, and Aug 1, 1996, were included (n = 856). An estimate of the odds ratio (OR) and 95% CI for the association between patient age and in-hospital major morbidity or mortality after elective AAR was made, controlling for significant risk factors. RESULTS Among the 856 patients, 170 had a nonfatal complication (136 with major and 34 with minor complications), and 11 patients (1.3%) died. The final logistic regression model demonstrated a mild association between increasing age and rate of major postoperative complications, including death (for each increase in age of 10 years: OR, 1.23; 95% CI, 1.00-1.52; P =.052). Other significant covariates in the final model included cardiac disease (OR, 2.84; 95% CI, 1.18-6.86; P =.020), pulmonary disease (OR, 1.96; 95% CI, 1.35-2.84; P =.0004), and renal disease (OR, 2.57; 95% CI, 1.66-3.99; P =.0001). Increasing age was associated with a moderate increase in the rate of death (for each increase in age of 10 years: OR, 2.74; 95% CI, 1.22-6.16; P =.015) in a model with cardiac disease as the only significant covariate (OR, 14.67; 95% CI, 3.46-62.16; P =.0003). CONCLUSION For patients undergoing elective AAR, increasing patient age is associated with a small increase in risk for in-hospital morbidity or mortality. However, significant cardiac, pulmonary, or renal disease is associated with a much greater risk of postoperative complications, and, therefore, advanced age should not be the sole basis of exclusion for otherwise suitable candidates for elective AAR.
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Guterres SS, Weiss V, de Lucca Freitas L, Pohlmann AR. Influence of benzyl benzoate as oil core on the physicochemical properties of spray-dried powders from polymeric nanocapsules containing indomethacin. Drug Deliv 2000; 7:195-9. [PMID: 11195425 DOI: 10.1080/107175400455119] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
To prepare spray-dried powders of poly(D,L-lactic acid) (PLA) or poly-epsilon-caprolactone (P epsilonC) from colloidal suspensions containing indomethacin (IND) using benzyl benzoate (BnB), nanocapsules (NC) were prepared by nanoprecipitation. To select the best NC formulations, increasing drug concentrations were tested (1.0, 1.5, or 2.0 mg/mL). The particle size was measured by Nanosizer. Spray-dried powders (SDP) were prepared by addition of Aerosil 200 into suspensions of NC. IND was assayed by HPLC. Free IND was determined using an Ultrafree. NC-SPD were examined under SEM. The particle sizes of all formulations are in the sub-300 nm range and are IND-associated, with drug recovery close to 100%. After 1 month, the formulations with highest drug content (2.0 mg/mL) showed a decline of total quantity of IND. After spray-drying, IND recovery for SDP presented values above 100%, indicating that the drug was concentrated from loss of mass during the process. To verify the relationship of oil phase with this loss of mass, similar NC (IND 1.5 mg/mL) prepared with Miglyol 810 (MI) were spray-dried, and SEM analysis showed nanostructures adsorbed onto SiO2. Similar nano-structures were not visualized for NC samples prepared with BnB. A swelling experiment showed the complete dissolution of both polymer by the BnB, whereas for MI the polymer masses remained unchanged. In conclusion, BnB is a solvent for PLA and P epsilonC and this ester is entrained during spray-drying. Despite the use of BnB in formulations of NC, PLA, or P epsilonC, colloidal suspensions prepared with BnB could be micelles instead of nanocapsules.
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Bantscheff M, Perraud AL, Bock A, Rippe K, Weiss V, Glocker M, Gross R. Structure-function relationships in the Bvg and Evg two-component phosphorelay systems. Int J Med Microbiol 2000; 290:317-23. [PMID: 11111905 DOI: 10.1016/s1438-4221(00)80031-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The unorthodox two-component phosphorelay systems BvgAS and EvgAS of Bordetella pertussis and E. coli, respectively, are suitable model systems to investigate the molecular basis of signalling specificity, because, despite their high relatedness on the sequence level, they do not cross-talk to each other. We could show that the two systems belong to the obligate type of phosphorelay systems and that signalling specificity is mediated by the HPt modules of the histidine kinases and the receiver domains of the effector proteins. To gain more insight into signalling specificity on the molecular level, we started a detailed structural analysis of the respective proteins using a combination of genetic and biochemical methods including limited proteolysis and chemical modification of purified proteins and their mass spectrometrical analysis.
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Weiss V, Sonka K, Pretl M, Dostálová S, Klozar J, Rambousek P, Marek J, Haas T. Prevalence of the sleep apnea syndrome in acromegaly population. J Endocrinol Invest 2000; 23:515-9. [PMID: 11021767 DOI: 10.1007/bf03343767] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The prevalence of sleep apnea syndrome (SAS) in acromegaly is high. Consequences of SAS are serious and are associated with increased morbidity and mortality. The aim of this study was to assess the relative frequency and predictive factors for SAS in a group of patients with acromegaly (n=55). The presence of SAS was evaluated using the Polymesam device. Hormonal and clinical examination consisted of assessment of growth hormone, insulin-like growth factor I plasma levels, body mass index (BMI), neck circumference, age, sex, treatment modes of acromegaly and ear, nose and throat (ENT) examination. The relative frequency of SAS in our group of patients with acromegaly was 75%. Independent predictors of SAS were: increased activity of acromegaly, higher age and neck circumference. No association between SAS and BMI and ENT findings was observed. The role of gender was controversial.
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Weiss V. [The fluoride content in children's toothpastes]. SCHWEIZER MONATSSCHRIFT FUR ZAHNMEDIZIN = REVUE MENSUELLE SUISSE D'ODONTO-STOMATOLOGIE = RIVISTA MENSILE SVIZZERA DI ODONTOLOGIA E STOMATOLOGIA 2000; 109:1135-7. [PMID: 10939933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Krsek M, Ceska R, Horínek A, Horejsí B, Weiss V. Type III hyperlipoproteinaemia and primary amenorrhoea associated with severe hypothyroidism. Acta Paediatr 2000; 89:1023-4. [PMID: 10976851 DOI: 10.1080/080352500750043558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
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Sonka K, Weiss V, Dostálová S, Pretl M, Marek J, Horínek D, Faltýnová E, Rambousek P, Busek P, Hána V. [Sleep apnea syndrome in acromegaly. Treatment and development-- retrospective analysis]. SBORNIK LEKARSKY 2000; 100:45-52. [PMID: 10860125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
In total 56 subjects with acromegaly (37 men and 19 females) were examined in attempt to find sleep apnoea syndrome (SAS). The examination consisted of clinical examination and of all-night monitoring MESAM4 or polyMESAM. The diagnosis of SAS was established in 76.4% of subjects: 31 men and 11 females, average age 51.8 (SD +/- 9.6) years. The average ODI (oxygen desaturation index--number of oxygen saturation drops per 1 hour of sleep) of SAS patients was 29.2 (+/- 20.7). The therapy of SAS was recommended to 27 patients: sleeping position on the side (3 patients), reduction of the weight (8 patients), change of hypnotic drug (1 patient) and CPAP--continuous positive airway pressure (24 patients). CPAP titration was performed in 18 patients (in one subject the titration was repeated 4 years later). CPAP was titrated within all-night polysomnography in 10 subjects and in 9 subjects using self adjusting CPAP. Primary acceptance of CPAP was 94.4%. The average CPAP pressure was 7.8 (+/- 2.1) mbar. The theoretical duration of CPAP use was 546.6 (+/- 533.7) days. Long term compliance was considered as sufficient (weekly 25 hours or more) in 66.7% of patients. Ten patients underwent important acromegaly therapy or its change during the follow up and the improvement or the disappearance of SAS symptoms occurred in 6 of them.
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Lin PH, Chen C, Surowiec SM, Conklin B, Bush RL, Chaikof EL, Lumsden AB, Weiss V. A porcine model of carotid artery thrombosis for thrombolytic therapy and angioplasty: application of PTFE graft-induced stenosis. J Endovasc Ther 2000; 7:227-35. [PMID: 10883961 DOI: 10.1177/152660280000700310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To develop a porcine carotid artery thrombosis model for the evaluation of thrombolytic therapy and adjunctive angioplasty procedures. METHODS Bilateral carotid thrombosis was induced in 16 pigs using endothelial crush injury followed by external polytetrafluoroethylene (PTFE, 5 x 2 cm2) wrap placement to create segmental carotid stenosis. Light microscopy was used to examine thrombus composition. Selective carotid catheterization was performed via a femoral approach. Two hours following carotid artery occlusion, a urokinase (250,000 IU) and heparin (1000 U) solution was pulse-sprayed in 1 carotid artery while the contralateral vessel received the control saline vehicle. The efficacy of thrombolytic therapy was assessed using carotid arteriography and intravascular ultrasound. The feasibility and technical efficacy of balloon angioplasty within the carotid stenosis model were also evaluated. RESULTS Carotid artery occlusion occurred in 30 +/- 6 minutes following endothelial injury plus PTFE wrap placement. Histological examination of carotid arteries showed endothelial irregularity with fibrin-rich and platelet-rich thrombus. Urokinase was effective in recanalizing all occluded arteries (100%), while the control saline vehicle showed no effective thrombolysis (p < 0.001). Angioplasty was successful in restoring normal diameter in all arteries (100%). CONCLUSIONS This carotid artery thrombosis model, which incorporates intimal injury with segmental stenosis, is simple to create and reproducible. It provides not only a model for the evaluation of thrombolytic therapy but also a practical training tool for adjunctive endovascular interventions.
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Perraud AL, Rippe K, Bantscheff M, Glocker M, Lucassen M, Jung K, Sebald W, Weiss V, Gross R. Dimerization of signalling modules of the EvgAS and BvgAS phosphorelay systems. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1478:341-54. [PMID: 10825546 DOI: 10.1016/s0167-4838(00)00052-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Biophysical and biochemical properties of signalling proteins or domains derived from the unorthodox EvgAS and BvgAS two-component phosphorelay systems of Escherichia coli and Bordetella pertussis were investigated. Oligomerization of the effector proteins EvgA and BvgA and of truncated EvgS and BvgS derived signalling proteins containing the receiver and histidine containing phosphotransfer (HPt) domains or comprising only the HPt domains were characterized by native gel electrophoresis, gel permeation experiments and analytical ultracentrifugation. The results obtained by the different methods are consistent with non-phosphorylated EvgA and BvgA proteins being dimers in solution with a dissociation constant significantly below 1 microM. In contrast, all sensor derived domains of EvgS and BvgS were observed to be monomers in vitro. No indications for a phosphorylation induced stimulation of oligomerization of the C-terminal histidine kinase domains could be detected. In agreement with these data, surface plasmon resonance studies revealed a 2:1 stoichiometry in the interaction of EvgA with the immobilized EvgS HPt domain and an affinity constant of 1. 24x10(6) M(-1).
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Kvasnicka J, Marek J, Kvasnicka T, Weiss V, Marková M, Stĕpán J, Umlaufová A. Increase of adhesion molecules, fibrinogen, type-1 plasminogen activator inhibitor and orosomucoid in growth hormone (GH) deficient adults and their modulation by recombinant human GH replacement. Clin Endocrinol (Oxf) 2000; 52:543-8. [PMID: 10792332 DOI: 10.1046/j.1365-2265.2000.01002.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE GH deficiency (GHD) is usually associated with a higher incidence of cardiovascular disease (CVD). The aim of this study was to establish whether patients with GHD, like those with CVD, show an increase in fibrinogen (FBG), type-1 plasminogen activator inhibitor (PAI-1), acute phase response proteins (APR), and soluble adhesion molecules. The effect of recombinant human GH (rhGH) replacement, on these parameters was also investigated. PATIENTS AND DESIGN Concentrations of PAI-1 antigen (Ag), adhesion molecules sE-selectin, sP-selectin, and intercellular adhesion molecule-1 (sICAM-1), FBG and levels of APR orosomucoid (ORM), and 'negative APR' transferrin (TRF) were established in 11 panhypopituitary (PHP) patients (eight men and three women, age median 39.0 years, body mass index (BMI) 27. 49 +/- 3.89 kg/m2) before and after 12-month replacement with rhGH. Control values were obtained by examination of 33 healthy age and sex matched subjects (24 men and nine women with BMI 24.16 +/- 1.99 kg/m2). RESULTS PHP patients had higher concentrations of ORM (0.80 +/- 0.25, vs. 0.61 +/- 0.20 g/l; P = 0.05), FBG (3.22 +/- 0.48, vs. 2.57 +/- 0.47 g/l; P = 0.001), PAI-1 Ag (97.12 +/- 33.23, vs. 44.11 +/- 21.40 microgram/l; P = 0.001), sE-selectin (72.42 +/- 28.35, vs. 42. 80 +/- 12.60 microgram/l; P = 0.004), sP-selectin (221.26 +/- 75.12, vs. 104.79 +/- 26.01 microgram/l; P = 0.001) sICAM-1 (409.75 +/- 137.78, vs. 228.10 +/- 37.54 microgram/l; P = 0.001), and lower levels of TRF (2.14 +/- 0.40, vs. 2.76 +/- 0.39 g/l; P = 0.001) than controls. After 12-month rhGH replacement the patients showed an increase of TRF (2.64 +/- 0.84 g/l, P = 0.037) and decrease of soluble adhesion molecules (sE-selectin 57.98 +/- 27.04 microgram/l, P = 0.01, sP-selectin 121.74 +/- 50.42 microgram/l, P = 0.007; and sICAM-1 279.95 +/- 88.32 microgram/l, P = 0.005), which then, similarly to the ORM (0. 67 +/- 0.12 g/l) and FBG level (2.82 +/- 0.51 g/l), did not statistically differ from the values in the control group. CONCLUSION rhGH replacement led to modulation of the 'inflammatory response' in panhypopituitary patients. This modulation occurred locally at vascular endothelium level where after rhGH replacement, sE-selectin, sP-selectin and sICAM-1 concentrations decreased, a similar effect as in the systemic inflammatory response, as was also apparent from the changes in acute phase response protein levels.
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Trummler A, Müller D, Weiss V. Clinical experience with a new tooth-colored dental restorative material (Ariston pHc) on primary teeth. AMERICAN JOURNAL OF DENTISTRY 1999; 12 Spec No:S15-6. [PMID: 10850241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Weiss V. [The fluoride content in children's toothpastes]. SCHWEIZER MONATSSCHRIFT FUR ZAHNMEDIZIN = REVUE MENSUELLE SUISSE D'ODONTO-STOMATOLOGIE = RIVISTA MENSILE SVIZZERA DI ODONTOLOGIA E STOMATOLOGIA 1999; 109:880-1. [PMID: 10515782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Bantscheff M, Weiss V, Glocker MO. Identification of linker regions and domain borders of the transcription activator protein NtrC from Escherichia coli by limited proteolysis, in-gel digestion, and mass spectrometry. Biochemistry 1999; 38:11012-20. [PMID: 10460156 DOI: 10.1021/bi990781k] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have developed a mass spectrometry based method for the identification of linker regions and domain borders in multidomain proteins. This approach combines limited proteolysis and in-gel proteolytic digestions and was applied to the determination of linkers in the transcription factor NtrC from Escherichia coli. Limited proteolysis of NtrC with thermolysin and papain revealed that initial digestion yielded two major bands in SDS-PAGE that were identified by mass spectrometry as the R-domain and the still covalently linked OC-domains. Subsequent steps in limited proteolysis afforded further cleavage of the OC-fragment into the O- and the C-domain at accessible amino acid residues. Mass spectrometric identification of the tryptic/thermolytic peptides obtained after in-gel total proteolysis of the SDS-PAGE-separated domains determined the domain borders and showed that the protease accessible linker between R- and O-domain comprised amino acids Val-131 and Gln-132 within the "Q-linker" in agreement with papain and subtilisin digestion. The region between amino acid residues Thr-389 and Gln-396 marked the hitherto unknown linker sequence that connects the O- with the C-domain. High abundances of proline-, alanine-, serine-, and glutamic acid residues were found in this linker structure (PASE-linker) of related NtrC response regulator proteins. While R- and C-domains remained stable under the applied limited proteolysis conditions, the O-domain was further truncated yielding a core fragment that comprised the sequence from Ile-140 to Arg-320. ATPase activity was lost after separation of the R-domain from the OC-fragment. However, binding of OC- and C- fragments to specific DNA was observed by characteristic band-shifts in migration retardation assays, indicating intact tertiary structures of the C-domain. The outlined strategy proved to be highly efficient and afforded lead information of tertiary structural features necessary for protein design and engineering and for structure-function studies.
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Forchhammer K, Hedler A, Strobel H, Weiss V. Heterotrimerization of PII-like signalling proteins: implications for PII-mediated signal transduction systems. Mol Microbiol 1999; 33:338-49. [PMID: 10411750 DOI: 10.1046/j.1365-2958.1999.01477.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PII-like signalling molecules are trimeric proteins composed of 12-13 kDa polypeptides encoded by the glnB gene family. Heterologous expression of a cyanobacterial glnB gene in Escherichia coli leads to an inactivation of E. coli's own PII signalling system. In the present work, we show that this effect is caused by the formation of functionally inactive heterotrimers between the cyanobacterial glnB gene product and the E. coli PII paralogues GlnB and GlnK. This led to the discovery that GlnK and GlnB of E. coli also form heterotrimers with each other. The influence of the oligomerization partner on the function of the single subunit was studied using heterotrimerization with the Synechococcus PII protein. Uridylylation of GlnB and GlnK was less efficient but still possible within these heterotrimers. In contrast, the ability of GlnB-UMP to stimulate the adenylyl-removing activity of GlnE (glutamine synthetase adenylyltransferase/removase) was almost completely abolished, confirming that rapid deadenylylation of glutamine synthetase upon nitrogen stepdown requires functional homotrimeric GlnB protein. Remarkably, however, rapid adenylylation of glutamine synthetase upon exposing nitrogen-starved cells to ammonium was shown to occur in the absence of a functional GlnB/GlnK signalling system as efficiently as in its presence.
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Spáčil J, Marek J, Weiss V, Malík J, Šperl M. Increasing common carotid artery intimal thickness during growth hormone replacement therapy in hypopituitary adults. Atherosclerosis 1999. [DOI: 10.1016/s0021-9150(99)80195-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Krsek M, Ceska R, Horinek A, Horejsi B, Weiss V. Type III hyperlipoproteinaemia in patient with severe hypothyroidism accompanied by primary amenorrhoea. Atherosclerosis 1999. [DOI: 10.1016/s0021-9150(99)80609-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Two-component systems are characterized by phosphotransfer reactions involving histidine and aspartate residues in highly conserved signalling domains. Although the basic principles of signal transduction by these systems have been elucidated, several important aspects, such as their integration into more complex cellular regulatory networks and the molecular basis of the specificity of signal transduction, remain unknown.
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Kramer G, Weiss V. Functional dissection of the transmitter module of the histidine kinase NtrB in Escherichia coli. Proc Natl Acad Sci U S A 1999; 96:604-9. [PMID: 9892680 PMCID: PMC15183 DOI: 10.1073/pnas.96.2.604] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Signal transduction by two-component systems involves phosphorylation and thereby activation of the response regulator by the cognate histidine kinase. Bifunctional histidine kinases have two opposing activities: depending on the environmental stimuli they either promote phosphorylation or stimulate the rapid dephosphorylation of the response regulator. To determine the mechanism of this switch, we analyzed the domain organization of the bifunctional histidine kinase NtrB. Based on sequence alignments with other histidine kinases and a deletion analysis, we defined three separate subdomains of the transmitter module, the H domain (amino acids 123-221), the N domain (amino acids 221-269), and the G domain (amino acids 269-349). The transmitter module, when separately expressed, exhibited a constitutive positive phenotype. In contrast, in the absence of the G domain, the H domain exhibits a constitutive negative phenotype. This negative regulatory activity of the H domain is inhibited by the G domain. The G domain could be physically uncoupled; when coexpressed with the H-N fragment, the constitutive positive phenotype of the transmitter was restored. We demonstrate, in vitro, that the constitutive negative phenotype of the fragments lacking the G domain is caused by stimulation of dephosphorylation of the response regulator NtrC-P. Based on our analysis, we suggest that the function of the sensor domain is to control the interaction of the H and G domains. If these subdomains interact, NtrB acts as a positive regulator; if they cannot interact, NtrB acts as a negative regulator.
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Marek J, Kvasnicka J, Weiss V, Marková M, Hass T. [Can normalization of vascular cytoadhesive activity be explained by the anti-atherosclerosis effect of growth hormone?]. CASOPIS LEKARU CESKYCH 1998; 137:690-3. [PMID: 9929936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
BACKGROUND The increased mortality caused by premature atherosclerosis has been shown among patients with hypopituitarism receiving conventional hormone treatment but with unsubstituted growth hormone deficiency. This experience belongs among the most important arguments in favour of replacement with growth hormone. The mechanisms of the antiatherogenic effect of growth hormone are poorly understood. The protective effect of growth hormone on the vascular endothel and its intervention in the clotting process, which have not been yet elucidated, may be the causative factors. METHODS AND RESULTS The endothelial damage as given by measuring of circulating soluble cytoadhesive molecules sE-selectin, sP-selectin and intercellular adhesive molecule 1 (ICAM 1) was measured in 15 adult panhypopituitaric patients before and after 1 year treatment with recombinant human growth hormone. The blood levels of all of these cytoadhesive molecules decreased significantly (p < 0.01) during the treatment. None of the concomitantly followed coagulation tests (prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, von Willebrand's factor and D-dimer) was significantly changed during the treatment. The tendency to decrease (p = 0.054) was observed with antithrombin III. CONCLUSIONS The decrease of circulating cytoadhesive molecules in blood during the treatment of growth hormone gives evidence for its protective effect, either direct or mediated, on the vascular endothel. These findings could bring an explantation for the premature atherosclerotic changes in hypopituitarism and antiatherogenic effect of growth hormone.
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Lumsden AB, Weiss V, Pitts M, MacDonald MJ, Surowiec SM, Ofenloch JC. Local anesthesia for above knee femoropopliteal bypass: an alternative technique to endoluminal bypass grafting. CARDIOVASCULAR SURGERY (LONDON, ENGLAND) 1998; 6:262-7. [PMID: 9705098 DOI: 10.1016/s0967-2109(97)00165-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND The majority of patients with peripheral vascular disease have associated medical illnesses that contribute to a substantial incidence of perioperative complications. Some of the these complications may be related to the choice of anesthetic used. An ideal anesthetic would provide good analgesia, have few complications associated with its use, including minimizing hemodynamic instability, and provide an adequate surgical environment. MATERIALS AND METHODS Ten patients with an occluded superficial femoral artery and claudication or rest pain were selected. Eligibility criteria were a non-obese thigh and an above knee popliteal segment of at least 10 cm. Lidocaine local anesthesia with systemic sedation was employed. Above knee femoropopliteal bypasses were performed in all patients. Intraoperative fluid volume, anesthetic dose and perioperative morbidity were recorded. RESULTS All patients tolerated the procedure well. The operating environment was excellent. Intraoperative fluid requirements were less for patients receiving local anesthesia as compared with a similar group of patients undergoing above knee femoropopliteal bypass receiving regional anesthesia (mean 1750 ml versus 3386 ml). The mean dosage of lidocaine (0.5%) was 367 mg over a mean of 116 min operating time. All patients ambulated within 8 hours. There was no perioperative morbidity, mortality or graft occlusion. CONCLUSION This technique is easy to perform and further reduces the systemic magnitude of anesthesia, while providing excellent perioperative analgesia and a satisfactory surgical environment. It may be ideal for the high risk patient, as intraoperative fluid volume requirements are reduced. In an era where endoluminal bypass grafting is being increasingly advocated, this technique retains the benefits of bypass grafting while possibly reducing the physiological insult.
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Sevenich FW, Langowski J, Weiss V, Rippe K. DNA binding and oligomerization of NtrC studied by fluorescence anisotropy and fluorescence correlation spectroscopy. Nucleic Acids Res 1998; 26:1373-81. [PMID: 9490780 PMCID: PMC147426 DOI: 10.1093/nar/26.6.1373] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Fluorescence anisotropy and fluorescence correlation spectroscopy measurements of rhodamine-labeled DNA oligonucleotide duplexes have been used to determine equilibrium binding constants for DNA binding of the prokaryotic transcription activator protein NtrC. Measurements were made with wild-type NtrC from Escherichia coli and the constitutively active mutant NtrCS160Ffrom Salmonella using DNA duplexes with one or two binding sites. The following results were obtained: (i) the dissociation constant K d for binding of one NtrC dimer to a single binding site was the same for the wild-type and mutant proteins within the error of measurement. (ii) The value of K d decreased from 1.4 +/- 0.7 x 10(-11) M at 15 mM K acetate to 5.8 +/- 2.6 x 10(-9) M at 600 mM K acetate. From the salt dependence of the dissociation constant we calculated that two ion pairs form upon binding of one dimeric protein to the DNA. (iii) Binding of two NtrC dimers to the DNA duplex with two binding sites occured with essentially no cooperativity. Titration curves of NtrCS160Fbinding to the same duplex demonstrated that more than two protein dimers of the mutant protein could bind to the DNA.
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Perraud AL, Kimmel B, Weiss V, Gross R. Specificity of the BvgAS and EvgAS phosphorelay is mediated by the C-terminal HPt domains of the sensor proteins. Mol Microbiol 1998; 27:875-87. [PMID: 9535079 DOI: 10.1046/j.1365-2958.1998.00716.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite the presence of highly conserved signalling modules, significant cross-communication between different two-component systems has only rarely been observed. Domain swapping and the characterization of liberated signalling modules enabled us to characterize in vitro the protein domains that mediate specificity and are responsible for the high fidelity in the phosphorelay of the unorthodox Bvg and Evg two-component systems. Under equimolar conditions, significant in vitro phosphorylation of purified BvgA and EvgA proteins was only obtained by their histidine kinases, BvgS and EvgS respectively. One hybrid histidine kinase consisting of the BvgS transmitter and HPt domains and of the EvgS receiver domain (BvgS-TO-EvgS-R) was able to phosphorylate BvgA but not EvgA. In contrast, the hybrid protein consisting of the BvgS transmitter and the EvgS receiver and HPt domains (BvgS-T-EvgS-RO) was unable to phosphorylate BvgA but efficiently phosphorylated EvgA. These results demonstrate that the C-terminal HPt domains of the sensor proteins endow the unorthodox two-component systems with a high specificity for the corresponding regulator protein. In the case of the response regulators, the receiver but not the output domains contribute to the specific interaction with the histidine kinases, because a hybrid protein consisting of the EvgA receiver and the BvgA output domain could only be phosphorylated by the EvgS protein.
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Weiss V. [Growth hormone deficiency and its treatment in adults]. CASOPIS LEKARU CESKYCH 1998; 137:120-3. [PMID: 9531734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Deficiency of growth hormone produced in the pituitary is manifested not only in children by impaired growth but also in adults. It is encountered most frequently in adults after surgery or irradiation in the hypothalamo-pituitary area, less frequently in idiopathic disorders of growth hormone production and secretion, either isolated or in conjunction with other trophic pituitary hormones. The diagnosis of growth hormone deficiency must be assessed by dynamic stimulation tests: most frequently the insulin stimulation test is used. Growth hormone deficiency in adult age is manifested by various non-specific symptoms which resemble symptoms (manifestations) of ageing: increase of adipose tissue, deterioration of lipid metabolism, osteopenia, impaired cardiac output and others; the symptoms recede partly if growth hormone is administered for a prolonged period. Clinical trials which are under way should define not only suitable indications but also ways of administration of this expensive treatment.
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Weiss V, Needlman R. To teach is to learn twice. Resident teachers learn more. ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE 1998; 152:190-2. [PMID: 9491047 DOI: 10.1001/archpedi.152.2.190] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVES To describe the formal teaching activities of pediatric residents and to assess how the act of formal teaching affects residents' acquisition and retention of knowledge. DESIGN AND METHODS Randomized controlled trial. Forty-three pediatric residents in a university-based program were surveyed about their teaching activities, given a pretest on a predetermined topic (oral rehydration), then randomly assigned to either teach (n = 18) or listen to (n = 25) a 30-minute lecture on that topic; 6 to 8 weeks later they completed a posttest. The difference between [retest and posttest scores was calculated for each resident as an index of knowledge acquisition. RESULTS The mean number of resident teaching events per year was 3.5 for interns (n = 16), 2.9 for junior residents (n = 11), and 6.9 for senior residents (n = 16). Self-reported comfort with the teaching role, ability to hold a group's attention, and desire to teach were similar across year of training. Prior to randomization, teachers (experimental group) reported less interest in oral rehydration that did listeners (control group) (P < .03). However, knowledge acquisition was significantly greater for teachers than for listeners (posttest score minus pretest score [mean +/- SD], 6.1 +/- 4.2 vs 3.2 +/- 2.5; P < .01). IMPLICATIONS Among pediatric residents, formal teaching enhances knowledge acquisition relative to self-study and lecture attendance.
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Stĕpán J, Weiss V, Marek J, Krsek M, Masatová A, Hána V. [Spontaneous remission of corticosteroid osteopenia after successful surgical treatment of Cushing's syndrome. A cross-sectional study]. CASOPIS LEKARU CESKYCH 1997; 136:464-7. [PMID: 9340192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Osteoporosis is one of the most serious consequences of Cushing's syndrome. Only a small number of longitudinal observations on bone mineral density (BMD) in patients with treated Cushing's syndrome have been reported so far. To evaluate changes in bone mass in patients with Cushing's syndrome after surgical cure of the disease, BMD was evaluated cross-sectionally. METHODS AND RESULTS BMD (DPX-L, Lunar) was measured in the lumbar spine and femoral neck (i.e. in skeletal areas with high proportion of trabecular and cortical bone, respectively) in 72 patients after successful surgical cure of Cushing's syndrome (8 men, 34 women before menopause and 30 women after menopause who were not on hormone replacement therapy). No other drug's interfering with skeletal metabolism were used. The reference group consisted of young healthy Czech women and/or men. The mean lumbar spine and femoral neck BMD increased to normal values within 3 and 5 years after surgery, respectively. In women after menopause, however, the significant positive relationship between BMD and time after surgery was negatively influenced by time after menopause. It is likely that several other factors contributed to the increase in bone mass in the patients (cure of hypercortisolism, recovery from hypogonadism and restoration of muscle strength). CONCLUSIONS After surgical cure of Cushing's syndrome in premenopausal women and in men, BMD rapidly and substantially increases. The recovery is negatively affected by estrogen deficiency in postmenopause.
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