Second-order stereology for planar fibre processes

Three different stereological methods for the determination of second-order quantities of planar fibre processes which have been suggested in the literature are considered. Proofs of the formulae are given (also by using a new integral geometric formula), relations between the methods are derived and the prerequisites are discussed. Furthermore, edge-corrected unbiased estimators for the second-order quantities are given.

Quality of Basic Life Support - A Comparison between Medical Students and Paramedics

INTRODUCTION

Poor survival rates after cardiac arrest can partly be explained by poor basic life support skills in medical professionals.

AIM

This study aimed to assess quality of basic life support in medical students and paramedics.

MATERIALS AND METHODS

We conducted a prospective observational study with 100 early medical students (group A), 100 late medical students (group B) and 100 paramedics (group C), performing a 20-minute basic life support simulation in teams of two. Average frequency and absolute number of chest compressions per minute (mean (±SD)), chest decompression (millimetres of compression remaining, mean (±SD)), hands-off-time (seconds/minute, mean (±SD)), frequency of switching positions between ventilation and chest compression (per 20 minutes) and rate of sufficient compressions (depth ≥50mm) were assessed as quality parameters of CPR.

RESULTS

In groups A, B and C the rates of sufficiently deep chest compressions were 56%, 42% and 52%, respectively, without significant differences. Male gender and real-life CPR experience were significantly associated with deeper chest compression. Frequency and number of chest compressions were within recommended goals in at least 96% of all groups. Remaining chest compressions were 6 mm (±2), 6 mm (±2) and 5 mm (±2) with a significant difference between group A and C (p=0.017). Hands-off times were 6s/min (±1), 5s/min (±1) and 4s/min (±1), which was significantly different across all three groups.

CONCLUSION

Overall, paramedics tended to show better quality of CPR compared to medical students. Though, chest compression depth as an important quality characteristic of CPR was insufficient in almost 50% of participants, even in well trained paramedics. Therefore, we suggest that an effort should be made to find better ways to educate health care professionals in BLS.

Cytokine and Chemokine Signature in Elite Versus Viremic Controllers Infected with HIV

HIV long-term nonprogressors (LTNPs) maintaining high CD4(+) T-cell counts without antiretroviral therapy (ART) are divided into elite controllers (ECs) with undetectable and viremic controllers (VCs) with low viral loads. Little is known about the long-term changes of T-cell subsets and inflammation patterns in ECs versus VCs. The aim of the study was to explore the long-term evolution of CD4(+) T-cell levels in LTNPs and to analyze cytokine profiles in ECs versus VCs. Nineteen ECs and 15 VCs were enrolled from the natural virus controller cohort (NaViC). T-cell counts were monitored over years, the mean annual change was calculated, and plasma concentrations of 25 cytokines were evaluated using a multiplex bead array. While absolute numbers of T cells did not differ between ECs and VCs over time, we observed a significant decrease of CD4(+) T-cell percentages in VCs, but not in ECs (median [interquartile range]: ECs: 37% [28-41] vs. VCs: 29% [25-34]; p = .02). ECs had lower levels of macrophage inflammatory protein-1β (MIP-1β, p = .003), interferon γ-induced protein-10 (IP-10, p = .03), and monokine induced by interferon-γ (MIG, p = .02). CD4(+) T-cell percentages inversely correlated with MIP 1-β (r = -0.42, p = .017) and IP-10 (r = -0.77, p < .0001). A subtle decline of CD4(+) T-cell percentages could be observed in VCs, but not in ECs, which was associated with higher plasma levels of proinflammatory cytokines. Hence, even low levels of HIV replication might go along with a progressive decline in CD4(+) T-cell counts in LTNPs.

The EcoCyc Database

EcoCyc is a bioinformatics database available at EcoCyc.org that describes the genome and the biochemical machinery of Escherichia coli K-12 MG1655. The long-term goal of the project is to describe the complete molecular catalog of the E. coli cell, as well as the functions of each of its molecular parts, to facilitate a system-level understanding of E. coli. EcoCyc is an electronic reference source for E. coli biologists and for biologists who work with related microorganisms. The database includes information pages on each E. coli gene, metabolite, reaction, operon, and metabolic pathway. The database also includes information on E. coli gene essentiality and on nutrient conditions that do or do not support the growth of E. coli. The website and downloadable software contain tools for analysis of high-throughput data sets. In addition, a steady-state metabolic flux model is generated from each new version of EcoCyc. The model can predict metabolic flux rates, nutrient uptake rates, and growth rates for different gene knockouts and nutrient conditions. This review provides a detailed description of the data content of EcoCyc and of the procedures by which this content is generated.

Disposition of midazolam in asphyxiated neonates receiving therapeutic hypothermia--a pilot study

Moderate hypothermia has become an established therapy for asphyxiated neonates. Midazolam is a frequently used sedative for this indication, although it has never been investigated how therapeutic hypothermia and asphyxia influence midazolam metabolism in neonates.9 asphyxiated newborns were treated with whole body hypothermia of 32-34°C for 72 h and all of them received continuous midazolam infusion for sedation. Serum concentrations of midazolam and its metabolites 1-hydroxy-midazolam and 4-hydroxy-midazolam were measured during hypothermia and the rewarming period. Renal and hepatic parameters were assessed to take into account the influence of asphyxia related renal or hepatic impairment.We found a high interindividual variability of serum midazolam concentrations in asphyxiated neonates with therapeutic hypothermia; median midazolam concentration was 369.3 ng/ml (minimum 36.6; maximum 3 218.6 ng/ml). The population pharmacokinetic model revealed a midazolam clearance of 2.57 ml/kg/min, comparable to midazolam clearances observed in normothermic critically ill neonates. However, midazolam clearance was significantly decreased in patients with asphyxia related renal and hepatic impairment.It seems that isolated hypothermia does not significantly influence midazolam metabolism. However, neonates with asphyxia related hepatic and renal impairment are at risk of generating unexpectedly high serum midazolam concentrations. In addition pronounced interindividual variability of midazolam metabolism may contribute to dangerously high midazolam concentrations.

Evidence classification of high-throughput protocols and confidence integration in RegulonDB

RegulonDB provides curated information on the transcriptional regulatory network of Escherichia coli and contains both experimental data and computationally predicted objects. To account for the heterogeneity of these data, we introduced in version 6.0, a two-tier rating system for the strength of evidence, classifying evidence as either ‘weak’ or ‘strong’ (Gama-Castro,S., Jimenez-Jacinto,V., Peralta-Gil,M. et al. RegulonDB (Version 6.0): gene regulation model of Escherichia Coli K-12 beyond transcription, active (experimental) annotated promoters and textpresso navigation. Nucleic Acids Res., 2008;36:D120–D124.). We now add to our classification scheme the classification of high-throughput evidence, including chromatin immunoprecipitation (ChIP) and RNA-seq technologies. To integrate these data into RegulonDB, we present two strategies for the evaluation of confidence, statistical validation and independent cross-validation. Statistical validation involves verification of ChIP data for transcription factor-binding sites, using tools for motif discovery and quality assessment of the discovered matrices. Independent cross-validation combines independent evidence with the intention to mutually exclude false positives. Both statistical validation and cross-validation allow to upgrade subsets of data that are supported by weak evidence to a higher confidence level. Likewise, cross-validation of strong confidence data extends our two-tier rating system to a three-tier system by introducing a third confidence score ‘confirmed’.

Database URL:http://regulondb.ccg.unam.mx/

RegulonDB v8.0: omics data sets, evolutionary conservation, regulatory phrases, cross-validated gold standards and more

This article summarizes our progress with RegulonDB (http://regulondb.ccg.unam.mx/) during the past 2 years. We have kept up-to-date the knowledge from the published literature regarding transcriptional regulation in Escherichia coli K-12. We have maintained and expanded our curation efforts to improve the breadth and quality of the encoded experimental knowledge, and we have implemented criteria for the quality of our computational predictions. Regulatory phrases now provide high-level descriptions of regulatory regions. We expanded the assignment of quality to various sources of evidence, particularly for knowledge generated through high-throughput (HT) technology. Based on our analysis of most relevant methods, we defined rules for determining the quality of evidence when multiple independent sources support an entry. With this latest release of RegulonDB, we present a new highly reliable larger collection of transcription start sites, a result of our experimental HT genome-wide efforts. These improvements, together with several novel enhancements (the tracks display, uploading format and curational guidelines), address the challenges of incorporating HT-generated knowledge into RegulonDB. Information on the evolutionary conservation of regulatory elements is also available now. Altogether, RegulonDB version 8.0 is a much better home for integrating knowledge on gene regulation from the sources of information currently available.

EcoCyc: fusing model organism databases with systems biology

EcoCyc (http://EcoCyc.org) is a model organism database built on the genome sequence of Escherichia coli K-12 MG1655. Expert manual curation of the functions of individual E. coli gene products in EcoCyc has been based on information found in the experimental literature for E. coli K-12-derived strains. Updates to EcoCyc content continue to improve the comprehensive picture of E. coli biology. The utility of EcoCyc is enhanced by new tools available on the EcoCyc web site, and the development of EcoCyc as a teaching tool is increasing the impact of the knowledge collected in EcoCyc.

RegulonDB version 7.0: transcriptional regulation of Escherichia coli K-12 integrated within genetic sensory response units (Gensor Units)

RegulonDB (http://regulondb.ccg.unam.mx/) is the primary reference database of the best-known regulatory network of any free-living organism, that of Escherichia coli K-12. The major conceptual change since 3 years ago is an expanded biological context so that transcriptional regulation is now part of a unit that initiates with the signal and continues with the signal transduction to the core of regulation, modifying expression of the affected target genes responsible for the response. We call these genetic sensory response units, or Gensor Units. We have initiated their high-level curation, with graphic maps and superreactions with links to other databases. Additional connectivity uses expandable submaps. RegulonDB has summaries for every transcription factor (TF) and TF-binding sites with internal symmetry. Several DNA-binding motifs and their sizes have been redefined and relocated. In addition to data from the literature, we have incorporated our own information on transcription start sites (TSSs) and transcriptional units (TUs), obtained by using high-throughput whole-genome sequencing technologies. A new portable drawing tool for genomic features is also now available, as well as new ways to download the data, including web services, files for several relational database manager systems and text files including BioPAX format.

[Randomly discovered enlargement in the region of sella turcica]

Computer tomography (CT) and magnetic resonance imaging (MRI) quite often detect unexpected cases of enlargement in the hypothalamus-hypophysial region, without the above methods being indicated for clinical manifested symptomatology provoked by the tumour. This is not surprising if we consider that autopsies show the presence of hypophysial adenomas of 10-15% of population on an average. X ray, CT or MRI are indicated in the case of head traumas, lateral nasal cavity inflammations, headaches, strokes, neurological diseases and other disorders. A number of tumours of diverse etiology occur in the hypothalamus-hypophysial region, but hypophysial adenomas are by far the most frequent among all (above 90 %). Among other primary enlargements, the most frequent are craniopharyngeomas and meningeomas, while other enlargements are by fare less common. Such randomly detected tumours are mostly asymptomatic, but targeted anamnesis may show some of the symptoms quite clearly. The symptomatology can be linked with possible slight hormonal overproduction of hypophysial adenomas, a deficit of hypophysial hormones or local manifestations of expansion. Exact assessment of MRI results, of hormonal activity of the enlargement, of the relation to surrounding structures, especially the optic nerves, and the assessment of hypophysial functions are important for the therapeutic decision. Depending on the type and extension of the tumour the options considered are pharmacotherapy (the treatment of choice in the case of prolactinomas), surgery, radiotherapy (today prevailingly using the gamma knife), and if no intervention is necessary, follow up with regular MRI examinations. Tumorous growth is more often observed in "macroadenomas" than in "microadenomas" (up to 10 mm).

Plasma levels of total and active ghrelin in acromegaly and growth hormone deficiency

Ghrelin is an endogenous growth hormone (GH) secretagogue recently isolated from the stomach. Although it possesses a strong GH releasing activity in vitro and in vivo, its physiological significance in endogenous GH secretion remains unclear. The aim of this study was to characterize plasma ghrelin levels in acromegaly and growth hormone deficiency (GHD). We investigated plasma total and active ghrelin in 21 patients with acromegaly, 9 patients with GHD and 24 age-, sex- and BMI-matched controls. In all subjects, we further assessed the concentrations of leptin, soluble leptin receptor, insulin, IGF-I, free IGF-I and IGFBP-1, 2, 3 and 6. Patients with acromegaly and GHD as well as control subjects showed similar levels of total ghrelin (controls 2.004+/-0.18 ng/ml, acromegalics 1.755+/-0.16 ng/ml, p=0.31, GHD patients 1.704+/-0.17 ng/ml, p=0.35) and active ghrelin (controls 0.057+/-0.01 ng/ml, acromegalics 0.047+/-0.01 ng/ml, p=0.29, GHD patients 0.062+/-0.01 ng/ml, p=0.73). In acromegalic patients plasma total ghrelin values correlated negatively with IGF-I (p<0.05), in GHD patients active ghrelin correlated with IGF-I positively (p<0.05). In the control group, total ghrelin correlated positively with IGFBP-2 (p<0.05) and negatively with active ghrelin (p=0.05), BMI (p<0.05), WHR (p<0.05), insulin (p=0.01) and IGF-I (p=0.05). Plasma active ghrelin correlated positively with IGFBP-3 (p=0.005) but negatively with total ghrelin and free IGF-I (p=0.01). In conclusion, all groups of the tested subjects showed similar plasma levels of total and active ghrelin. In acromegaly and growth hormone deficiency plasma ghrelin does not seem to be significantly affected by changes in GH secretion.

Transparenz in der Pflege - Dekubituserfassung auf Landkreisebene als Instrument der Qualitätssicherung

The medical diagnosis of bedsores often applies to open wounds. These wounds are caused by constant pressure to the skin of seniors who cannot change their position in bed or wheelchair without help. In severe cases these wounds extend through all layers of the skin with involvement of muscle and underlying bone. These ulcers can be very painful, so the mobility and quality of life of seniors is thoroughly reduced. Treatment of ulcers costs annually millions of Euro in Germany alone. Primary prevention of bedsores has not yet been established neither in Germany nor in Europe. The first step to improve the situation in a scientific manner has been to set up a comparable database. In order to change that, the German community of Ostalbkreis (part of the German Federal state of Baden-Wurttemberg) developed a process of nursing quality assurance as a project of the local agenda 21, initiated and supported by the health office of the community. Annual networked and anonymous survey from 2001 to 2003, each lasting three months every year, proved that the rate of non stratified prevalence could be reduced. For example the rate of all day spent with bedsores within the community could be reduced from 1.96 % in 2001, to 1.74 % in 2002 and finally to 1.62 % in 2003. During the survey as an additional bonus cooperation of community-organized nursing was optimised and quality assurance in nursing became a pole position of the community. During the QM-process a software was developed to process the survey: it is internet-based, published in the nursing-guide of Ostalbkreis, easy to manage and to establish in any nursing institution or community.

[Total body composition in adult patients with growth hormone deficiency before and after its administration]

Effect of growth hormone (GH) on the growth and development of children is generally known. Effects of GH in adults are favorable, though. The aim of the work was to verify effects of GH administration on body composition in adult patients with GH deficit (GHD). The authors examined 15 adult patients with GHD originated in 13 of them in adulthood and in two of them in childhood. Their mean age was 43.9 +/- 11.3 years, the mean body mass was 80.0 +/- 15.2 kg. The GH deficit was verified by the stimulation insulin tolerance test. For the period of 12 months, they were subcutaneously administered recombinant human GH in a substitution dose of 0.5 to 1.5 IU/m2 body surface/day. A stable substitution of the hormone was applied for the period of at least six months in all these patients provided any deficit of other hormones had not been demonstrated. The examination by whole-body dosimeter Lunar DPX-L was made in the patients before the GH treatment began and after 12 months of therapy. It enabled to determine the amount of lean body mass (LBM) and fatty mass. After 12 months of GH treatment the mean level of insulin-like growth factor (IGF-I) was increased (P = 0.002). A statistically significant increase of total LBM (48.6 +/- 9.8 vs. 50.8 +/- 9.9 kg, P = 0.004) developed, the fatty mass did not change. Nine of these 15 patients were further followed and the administration of GH proceeded for six months. The densitometric examination was repeated, but no change of LBM was observed. The administration of GH was halted and after the period of 12 months the whole-body densitometric examination was done. The increase of LBM lasted. The amount of fat mass did not change, a decrease of fatty mass was observed after the GH administration ended. After 12 months of GH treatment there was also an increase of maximal output reached on bicycle ergometer (157.3 +/- 34.2 vs. 197.5 +/- 68.1 W, P = 0.006). A positive correlation between LBM and maximal output reached on bicycle ergometer before GH administration (r = 0.58, P = 0.02) was observed. A favorable effect of the substitution dose of GS administered to adult patients with GHD on the increase of LBM and physical output was confirmed.

[Incidental findings of expansive processes in the sellar region]

The technologic advancement of imaging techniques especially computed tomography (CT) and magnetic resonance (MRI) is associated with an increasing number of incidentally discovered sellar masses. The endocrinologists are facing the problem to distinguish between benign and clinically often insignificant non-functioning pituitary adenomas (pituitary incidentalomas) and other pituitary or sellar and parasellar masses, which require further therapy. This paper gives an overview about different types of pituitary or sellar and parasellar masses, their aetiology and basic symptoms arising from either endocrine disturbances or as a result of mass effect of an enlarging tissue. Further, the paper shortly characterises most common pituitary and non-pituitary sellar masses that are necessary to distinguish. Finally, the basic diagnostic approach to the patients with sellar and parasellar masses is described.

[New avenues to quality assurance--a model project for recording bedsore incidence]

Bedsores can usually be avoided by adequate care and preventive measures. In the context of the local agenda process a local district office (Landratsamt) and inspection units initiated a variety of activities to promote sensitisation in health institutions and contribute to an increase in life quality of the persons concerned. Nearly all nursing care homes, domiciliary services and hospitals participated in a pilot study which was accompanied by the Fraunhofer IAO in Stuttgart. Objectives of the pilot study were to implement internal quality assurance to sensitise for persons the topic and to collect comparable data to achieve benchmarking. Software-tool institutions recorded data on care days, days spent with bedsores according to care level from July till September 01. Major result was that - although institutions had already a decreasing incidence in bedsores since the start of discussing the project - bedsore quotas could be further decreased from 2.15 to 1.84 %.

Mechanism of regulation of the bifunctional histidine kinase NtrB in Escherichia coli

NtrB is the bifunctional histidine kinase for nitrogen regulation. Dependent on the availability of nitrogen, it either autophosphorylates and serves as the phosphodonor for its cognate response regulator, NtrC, or, it promotes the rapid dephosphorylation of NtrC-P. The activity of NtrB depends on the interaction of two subdomains within its transmitter domain, the H-domain and the kinase domain. Both phosphotransfer activity and phosphatase activity reside in the H-domain. When separately expressed, this domain acts as a phosphatase. Interaction with the kinase domain results in the inhibition of the phosphatase activity and the phosphorylation of the conserved histidine of the H-domain.

[The sleep apnea syndrome in hypophyseal disorders with the exception of acromegaly]

The aim of the study was to ascertain the occurrence of the sleep apnoea syndrome (SAS) in patients after pituitary afunctional adenoma operation or in patients with other affection in sella turcica region except acromegaly patients. Eighty-one patients were addressed. Sixteen patients (eight men, eight women) underwent the examination; the rest of them had no interest to be explored. Afunctional pituitary adenoma was diagnosed in twelve patients, afunctional pituitary adenoma and subsequently optic glioma in one patient, craniopharyngioma in one patient, prolactinoma in one patient and undifferentiated cystic pituitary tumour in one patient. Neurological examination was done in all patients (standardized sleep questionnaire was included). SAS was quantified using PolyMESAM. Severity of SAS were set up from the value of M index (M = ODI.delta saturation; ODI--oxygen desaturation index). Mild SAS: 40 < M < 100; middle SAS: 100 < M < 210; severe SAS: M > 210. SAS was diagnosed in 13 patients: mild SAS in three of them (average value of M index: 81.0 +/- 12.7), moderate SAS in seven patients (average value of M index: 129.0 +/- 18.7) and severe SAS in three patients (average value of M index: 790.0 +/- 563.0). Therapy by continuous positive airway pressure (CPAP) was recommended in six patients. Five of them continue in using of CPAP--four patients with good compliance. The occurrence of SAS was 16.05% in measured group, higher than in normal population.

Late recurrence of lupus nephritis in a renal transplant recipient: response to mycophenolate mofetil

Clinically significant recurrence of lupus nephritis in the renal allograft is low, with an incidence of 1 to 3%, and usually occurs within the first 6 years after transplantation. We report an unusual case of a patient with end-stage renal disease caused by lupus nephritis who received a kidney transplant from a living relative; 13 years later, the patient had a severe recurrence of diffuse proliferative lupus nephritis. The patient relapsed after receiving intravenous cyclophosphamide therapy and had a partial response to oral mycophenolate mofetil. In this report we review the risk factors for the recurrence of the systemic lupus erythematosus in the kidney graft and the anti-lupus activity of mycophenolate mofetil.

Rational design and molecular characterization of a chimaeric response regulator protein

BvgA and EvgA are closely related response regulators from Bordetella pertussis and Escherichia coli. To analyze the domain borders and linker sequences of these proteins, we used limited proteolysis and matrix-assisted laser desorption/ionization-mass spectrometry analysis of the in-gel-digested proteolytic fragments. The thermolysin-sensitive linker regions were found to extend from Leu130 to Thr144 for BvgA and from Leu127 to Ser133 for EvgA. These data provided the rationale for the construction of the chimaeric protein HA. HA carries the EvgA receiver and BvgA output domains, fused in the central part of the linker sequences of the parent proteins. Thermolysin-sensitive sites of HA were found at positions identical with those in the EvgA and BvgA linker sequences, indicating intact folding of its receiver and output domains. Consistent with this, the chimaera showed virtually unchanged phosphorylation and dimerization properties. However, BvgA and HA differed in the effect of phosphorylation on their DNA-binding activities. In the case of BvgA, phosphorylation resulted in an increased affinity and specificity in DNA binding, whereas the DNA-binding properties of HA were not affected by phosphorylation. The chimaera HA was unable to activate transcription of the BvgA-dependent fha promoter, either in vivo or in vitro. These results indicate that the phosphorylation-induced activation of BvgA requires specific interactions between the receiver and output domains that are disturbed in the chimaera.

Craniofacial abnormalities and their relevance for sleep apnoea syndrome aetiopathogenesis in acromegaly

OBJECTIVE

To explain the effect of craniofacial relations on the development of the sleep apnoea syndrome (SAS) in acromegaly, and to elucidate how the activity of acromegaly affects the severity of SAS.

DESIGN

Prospective observational study.

METHODS

Cephalometry and sleep ventilation measurements were performed in 26 acromegalic men and in 96 men with SAS.

RESULTS

SAS was found in 20 acromegalic men. Compared with non-acromegalic men with SAS, patients with acromegaly and SAS were found to have: enlargement of almost all linear dimensions; increased angle indicating mandibular protrusion; increased difference between maxillary and mandibular protrusion; articular angle decrease; soft palate lengthening; and pharyngeal airway space (PAS) enlargement in the palatal and uvular-tip planes. A comparison of acromegalic men with and without SAS revealed no significant difference in the craniofacial skeleton, although there was a narrowing of the minimal PAS (MinPAS) and of PAS in the uvular-tip plane in patients with SAS. SAS was more frequent in the patients with active acromegaly. MinPAS in the patients with active acromegaly was narrower than in those without disease activity.

CONCLUSION

Skeletal abnormalities in acromegalic men with SAS were different from those in SAS patients without acromegaly. Upper airway narrowing due to changes in pharyngeal soft tissues takes a more relevant share in the development of SAS in acromegalic men than skeletal anomalies.

Age versus comorbidities as risk factors for complications after elective abdominal aortic reconstructive surgery

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.

Influence of benzyl benzoate as oil core on the physicochemical properties of spray-dried powders from polymeric nanocapsules containing indomethacin

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.

Structure-function relationships in the Bvg and Evg two-component phosphorelay systems

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.

Prevalence of the sleep apnea syndrome in acromegaly population

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.

[Sleep apnea syndrome in acromegaly. Treatment and development-- retrospective analysis]

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.

A porcine model of carotid artery thrombosis for thrombolytic therapy and angioplasty: application of PTFE graft-induced stenosis

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.

Dimerization of signalling modules of the EvgAS and BvgAS phosphorelay systems

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).

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

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.

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

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.

Heterotrimerization of PII-like signalling proteins: implications for PII-mediated signal transduction systems

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.

Signalling pathways in two-component phosphorelay systems

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.

Functional dissection of the transmitter module of the histidine kinase NtrB in Escherichia coli

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.

[Can normalization of vascular cytoadhesive activity be explained by the anti-atherosclerosis effect of growth hormone?]

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.

Local anesthesia for above knee femoropopliteal bypass: an alternative technique to endoluminal bypass grafting

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.

DNA binding and oligomerization of NtrC studied by fluorescence anisotropy and fluorescence correlation spectroscopy

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.

Specificity of the BvgAS and EvgAS phosphorelay is mediated by the C-terminal HPt domains of the sensor proteins

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.

[Growth hormone deficiency and its treatment in adults]

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.

To teach is to learn twice. Resident teachers learn more

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.