The influence of propofol on P-selectin expression and nitric oxide production in re-oxygenated human umbilical vein endothelial cells

BACKGROUND

Reperfusion injury is characterized by free radical production and endothelial inflammation. Neutrophils mediate much of the end-organ injury that occurs, requiring P-selectin-mediated neutrophil-endothelial adhesion, and this is associated with decreased endothelial nitric oxide production. Propofol has antioxidant properties in vitro which might abrogate this inflammation.

METHODS

Cultured human umbilical vein endothelial cells were exposed to 20 h of hypoxia and then returned to normoxic conditions. Cells were treated with saline, Diprivan 5 microg/l or propofol 5 microg/l for 4 h after re-oxygenation and were then examined for P-selectin expression and supernatant nitric oxide concentrations for 24 h. P-selectin was determined by flow cytometry, and culture supernatant nitric oxide was measured as nitrite.

RESULTS

In saline-treated cells, a biphasic increase in P-selectin expression was demonstrated at 30 min (P = 0.01) and 4 h (P = 0.023) after re-oxygenation. Propofol and Diprivan prevented these increases in P-selectin expression (P < 0.05). Four hours after re-oxygenation, propofol decreased endothelial nitric oxide production (P = 0.035).

CONCLUSION

This is the first study to demonstrate an effect of propofol upon endothelial P-selectin expression. Such an effect may be important in situations of reperfusion injury such as cardiac transplantation and coronary artery bypass surgery. We conclude that propofol attenuates re-oxygenation-induced endothelial inflammation in vitro.

Interleukin–8 Serum Levels at Fever Onset in Patients with Neutropenia Predict Early Medical Complications

BACKGROUND

Previous studies have shown that interleukin-8 serum levels in febrile neutropenic patients are significantly higher in patients with gram-negative bacteremia than in patients with other causes of fever and may indicate unfavorable outcomes. We assessed the value of interleukin-8 serum levels at fever onset to predict clinical complications in order to confirm these earlier findings.

PATIENTS AND METHODS

In a prospective observational study of adult patients receiving cancer chemotherapy, serum samples obtained at the onset of 147 febrile neutropenic episodes were measured by an immunoluminescence assay.

RESULTS

Complicated courses of fever including severe sepsis or septic shock, respiratory insufficiency or death were observed in 13 episodes (9%); in six episodes complications had developed within 1 week after fever onset and five of them were associated with bloodstream infections. At an interleukin-8 cutoff level of 1,000 pg/ml, these early complications were predicted with a sensitivity of 83%, a specificity of 97%, a positive predictive value of 50%, and a negative predictive value of 99%, respectively.

CONCLUSION

Interleukin-8 levels at fever onset may be used for the prediction of early medical complications associated with bacteremia and can help identify patients who might benefit from intensive care admission.

The 5A structure of heterologously expressed plant aquaporin SoPIP2;1

SoPIP2;1 is one of the major integral proteins in spinach leaf plasma membranes. In the Xenopus oocyte expression system its water channel activity is regulated by phosphorylation at the C terminus and in the first cytosolic loop. To assess its structure, SoPIP2;1 was heterologously expressed in Pichia pastoris as a His-tagged protein and in the non-tagged form. Both forms were reconstituted into 2D crystals in the presence of lipids. Tubular crystals and double-layered crystalline sheets of non-tagged SoPIP2;1 were observed and analyzed by cryo-electron microscopy. Crystalline sheets were highly ordered and diffracted electrons to a resolution of 2.96A. High-resolution projection maps of tilted specimens provided a 3D structure at 5A resolution. Superposition of the SoPIP2;1 potential map with the atomic model of AQP1 demonstrates the generally well conserved overall structure of water channels. Differences concerning the extracellular loop A explain the particular crystal contacts between oppositely oriented membrane sheets of SoPIP2;1 2D crystals, and may have a function in rapid volume changes observed in stomatal guard cells or mesophyll protoplasts. This crystal packing arrangement provides access to the phosphorylated C terminus as well as the loop B phosphorylation site for studies of channel gating.

Spontaneous osteonecrosis of the knee: biochemical markers of bone turnover and pathohistology

OBJECTIVE

The aim of this study was to evaluate bone metabolism in patients with spontaneous osteonecrosis (ON) of the medial femoral condyle.

METHOD

In 22 consecutive patients, undergoing total knee arthroplasty, biochemical markers of bone metabolism were measured in aspirates from cancellous bone and in samples obtained simultaneously from peripheral blood. Specimens of the medial femoral condyle were available for histologic examination and the lesion size, assessed on radiographs, was compared with the results from bone turnover measurements. Twenty patients with osteoarthritis (OA) of the knee served as a control. Bone-specific alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I N-terminal propeptide (PINP), and C-terminal cross-linking telopeptide (ICTP) were studied.

RESULTS

Mean serum levels of analytes were not different in patients with ON and OA. The serum concentrations averaged 16.2 vs 13.3 ng/mL (OC), 10.2 vs 12.1 ng/mL (bone ALP), 4.6 vs 4.1 ng/mL (ICTP), and 33.2 vs 40.4 ng/mL (PINP) in patients with ON and OA, respectively. In samples obtained from cancellous bone, mean concentrations of all markers were elevated significantly when compared to serum levels. The mean marker concentrations in samples obtained from cancellous bone were 33.8 vs 43.3 ng/mL (OC), 34.6 vs 37.3 ng/mL (bone ALP), 64.8 vs 36.1 ng/mL (ICTP, P=0.02), and 208.0 vs 176.2 ng/mL (PINP) in patients with ON and OA, respectively. The lesion size was at mean 440.5+/-275.8mm(2) in knees with ON and did not correlate with either serum or bone concentrations of all markers tested (P>0.1).

CONCLUSION

The marked elevation of markers in samples obtained from cancellous bone pointed at increased turnover in both diseases when compared to healthy individuals. In line with histologic findings of necrosis of subchondral bone, focal degradation of collagen type I was more pronounced in knees with ON. Mean serum concentrations of all markers, however, were not different from healthy individuals and thus did not provide any useful clue in the diagnosis spontaneous ON.

How to Improve Quality Assurance in Fluorometry: Fluorescence-Inherent Sources of Error and Suited Fluorescence Standards

The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requirements on fluorescence standards for the characterization and performance validation of fluorescence instruments, to enhance the comparability of fluorescence data, and to enable quantitative fluorescence analysis are discussed. Special emphasis is dedicated to spectral fluorescence standards and fluorescence intensity standards.

Non-Hodgkin lymphoma and benzene exposure: A systematic literature review

Epidemiological papers that address an association between benzene exposure and non-Hodgkin lymphoma (NHL) were identified and separated by study design. Eighteen studies contained 21 study groups-11 population-based case-control study groups, 3 nested occupation-based case-control study groups and 7 occupational benzene cohort study groups. Petroleum industry studies were not included. Only two of these 21 study groups showed statistically significant associations. However, these were among workers with multiple exposures across industries. Eleven of the 21 study groups presented ratios less than one, two equaled one, and eight were greater than one. Over all, about as many cases were observed (404) as expected (390.0) for an observed to expected ratio of 1.04 (0.94-1.14). After removal of the studies with multiple chemical exposures problems, the observed was 359 cases with 373.2 cases expected, yielding an odds ratio of 0.96 (0.86-1.06). Further assessment of an association with NHL should document the benzene exposure and separate out the contribution of non-benzene exposures.

Evaluation of penile revascularization for erectile dysfunction: a 10-year follow-up

The objective of this study was to report long-term success rates for penile revascularization (PR) and investigate factors responsible for failures. During the past 10 y, data were obtained on 52 patients who underwent PR. Surgical technique was selected according to preoperative arteriographic findings. The mean age was 28.5 y and the mean follow-up was 70.8 months. Success was defined as satisfactory intercourse without additional therapy. Overall success was 48%. Patients under 28 y showed a 73% success rate vs 23% in the older ones (P=0.0003). Nonsmokers had a 57% success compared to 29% in smokers (P=0.05). The presence of venous leak and type of procedure had an insignificant impact on success (P=0.33 and 0.23 respectively). To conclude, this curative treatment option is limited to a selective population with vasculogenic erectile dysfunction. We found that the cure rate of this procedure is maintained and long-term follow-up shows good results, especially in the young nonsmokers.

[Diagnosis of the antiphospholipid syndrome in anticoagulated patients]

The antiphospholipid syndrome is characterized by thromboembolic events and/or recurrent miscarriages in the presence of anticardiolipin antibodies and/or a lupus anticoagulant. Anticardiolipin antibodies are detected by ELISA whereas lupus anticoagulant detection includes a variety of coagulometric tests. However, a large number of patients with suspected antiphospholipid syndrome are anticoagulated with either heparin or coumadin when evaluated for the presence of a lupus anticoagulant and false positive test results may ensue, thus making coagulometric testing unreliable in this situation. Modifications of standard coagulometric tests have been suggested in order to circumvent this problem and studies of several patient cohorts have shown that the majority of patients with the antiphospholipid syndrome are anticardiolipin positive. However diagnosis in patients receiving anticoagulation remains a difficult task.

Atomic force bio-analytics

The atomic force microscope (AFM) allows biomolecules to be observed and manipulated under native conditions. It operates in buffer solution, produces molecular images with outstanding signal-to-noise ratio, and addresses single molecules. Progress in sample preparation and instrumentation has led to topographs that reveal sub-nanometer details and surface dynamics of biomolecules. Antibodies or oligonucleotides immobilized on cantilevers induce bending upon binding of the cognate biomolecule, allowing sub-picomolar concentrations to be measured. Biomolecules tethered between support and retracting AFM-tip produce force extension curves that reflect the mechanical stability of secondary structure elements. Furthermore, multifunctional tips may activate single molecules to observe them at work. In all cases, the cantilever is critical: its mechanical properties dictate the force-sensitivity and the scanning speed.

Isolation and characterization of new homing endonuclease specificities at individual target site positions

Homing endonucleases are highly specific DNA endonucleases, encoded within mobile introns or inteins, that induce targeted recombination, double-strand repair and gene conversion of their cognate target sites. Due to their biological function and high level of target specificity, these enzymes are under intense investigation as tools for gene targeting. These studies require that naturally occurring enzymes be redesigned to recognize novel target sites. Here, we report studies in which the homodimeric LAGLIDADG homing endonuclease I-CreI is altered at individual side-chains corresponding to contact points to distinct base-pairs in its target site. The resulting enzyme constructs drive specific elimination of selected DNA targets in vivo and display shifted specificities of DNA binding and cleavage in vitro. Crystal structures of two of these constructs demonstrate that substitution of individual side-chain/DNA contact patterns can occur with almost no structural deformation or rearrangement of the surrounding complex, facilitating an isolated, modular redesign strategy for homing endonuclease activity and specificity.

Oligomeric structure of the Bacillus subtilis cell division protein DivIVA determined by transmission electron microscopy

DivIVA from Bacillus subtilis is a bifunctional protein with distinct roles in cell division and sporulation. During vegetative growth, DivIVA regulates the activity of the MinCD complex, thus helping to direct cell division to the correct mid-cell position. DivIVA fulfils a quite different role during sporulation in B. subtilis when it directs the oriC region of the chromosome to the cell pole before asymmetric cell division. DivIVA is a 19.5 kDa protein with a large part of its structure predicted to form a tropomyosin-like alpha-helical coiled-coil. Here, we present a model for the quaternary structure of DivIVA, based on cryonegative stain transmission electron microscopy images. The purified protein appears as an elongated particle with lateral expansions at both ends producing a form that resembles a 'doggy-bone'. The particle mass estimated from these images agrees with the value of 145 kDa measured by analytical ultracentrifugation suggesting 6- to 8-mers. These DivIVA oligomers serve as building blocks in the formation of higher order assemblies giving rise to strings, wires and, finally, two-dimensional lattices in a time-dependent manner.

Hallux valgus and cartilage degeneration in the first metatarsophalangeal joint

This study relates the extent of cartilage lesions within the first metatarsophalangeal joint to hallux valgus.

We prospectively examined 265 first metatarsophalangeal joints of 196 patients with a mean age of 54.2 years at operation for the existence of cartilage lesions.

Grade I lesions were found in 41 feet (15.5%), grade II in 82 (30.9%), grade III in 51 (19.3%), grade IV in 20 (7.5%). Only 71 (26.8%) showed no cartilage lesion. Cartilage lesions were found within the metatarsosesamoid and metatarsophalangeal compartments in 66 feet (34.0%), within the metatarsophalangeal compartment in 26 (13.4%) and within the metatarsosesamoid compartment in 102 (52.6%). A statistically significant correlation was found between the grade of cartilage lesion and the hallux valgus angle, both for the changes within the metatarsophalangeal and the metatarsosesamoid joints.

The sheep as a model for coronary artery bypass surgery

The sheep is considered to be a suitable model for cardiovascular surgery because of its ease of handling, size, and vascular anatomy which bears close resemblance to the human. Several difficulties, however, have limited the use of the sheep for such a purpose-mainly the high infection rate resulting from median sternotomy incision and its susceptibility to intractable ventricular fibrillation (VF) with the slightest manipulation of the heart, and even the risk of short periods of myocardial ischaemia. We have used the sheep model extensively to perform coronary artery bypass surgery and were successful in overcoming these difficulties. Fifty-seven adult female sheep were used to test a new anastomotic device for the creation of a sutureless connection between venous and arterial grafts and the coronary arteries. The study required full access to the heart and great vessels and mobilization of one of the internal mammary arteries. Changing to the left lateral thoracotomy (LLT) approach solved the initial fatal problems of postoperative infected median sternotomy incisions. Aggressive prophylactic treatment with anti-arrhythmic drugs, maintenance of normothermia and myocardial preconditioning rendered the heart much less vulnerable to manipulations and ischaemia. These measures have reduced the mortality rate from 45% to 0% (P <0.0001). With specific operative techniques and pharmaceutical interventions, the sheep can be effectively and safely used as a model for coronary artery surgery.

Bilaterale Cochlea-Implantation bei unterschiedlicher Ertaubungsdauer

The effectiveness of cochlear implants in profoundly deaf patients could be demonstrated in the last years. One of the problems of these patients is the decreased speech understanding in noise. Therefore bilateral cochlear implantation seems to be obvious. Another problem of unilateral cochlear implantation is to predict the better side for implantation concerning speech understanding. Only a few factors seem to help for the choice of the side for implantation. One of these is duration of deafness. In other studies short duration of deafness is a significant predictor of good word recognition. We present a case of a deaf patient with a time gap of 23 years for deafness between both ears. The patient underwent bilateral cochlear implantation (Med-el Combi 40+) as one stage procedure. After activation of the speech processor he shows better speech understanding on that ear, which is deaf for more than 25 years. In addition he has further improvement of speech understanding in noise by using both implants compared to one. In unilateral cochlear implantation selection of the side might still be difficult. In bilateral cochlear implantation the better side is always implanted, which is an other advantage of bilateral cochlear implantation.

Membrane protein reconstitution and crystallization by controlled dilution

Efficient reconstitution of membrane proteins for functional analyses can be achieved by dilution of a ternary mixture containing proteins, lipids and detergents. Once the dilution reaches the point where the free detergent concentration would become lower than the critical micellar concentration, detergent is recruited from the bound detergent pool, and association of proteins and lipids is initiated. Here we show that dilution is also suitable for the assembly of two-dimensional crystals. A device has been designed that allows controlled dilution of a protein-lipid-detergent mixture to induce formation of densely packed or crystalline proteoliposomes. Turbidity is used to monitor the progress of reconstitution on-line, while dilution is achieved by computer-controlled addition of buffer solution in sub-microliter steps. This system has mainly been tested with porin OmpF, a typical beta-barrel protein, and aquaporin-1, a typical alpha-helical protein. The results demonstrate that large, highly ordered two-dimensional crystals can be produced by the dilution method.

[Excessive hyperferritinemia as an indication of a reactive hemophagocytosis syndrome]

HISTORY AND ADMISSION FINDINGS

A 17-year-old girl with a history of a polyarthritis of unknown etiology was admitted because of acute fever and general weakness. There were palpable cervical lymph nodes and her body temperature was 39.5 degrees C.

INVESTIGATIONS

GOT was raised to 282 U/1, GPT to 266 U/l lactate dehydrogenase to 1275 U/I and bilirubin to 0.6 mg/dl. The Quick value was 67%, albumin 28 mg/dl. White cell count was decreased to 1700/microl, with 43% granulocytes, 39% lymphocytes, 17% monocytes. Platelet count was 64,000/microl. Ultrasound revealed splenomegaly. Ferritin was markedly raised to 11,860 ng/ml (normal up to 150 ng/ml). An epstein-barr-virus infection was found.

THERAPY AND CLINICAL COURSE

Suspecting a reactive hemophagocytosis syndrome, she was treated with prednisolone (2 mg/kg). The diagnosis was confirmed by a bone marrow aspirate. The patient's condition and laboratory values improved rapidly.

CONCLUSION

Markedly increased ferritin levels in a clinically septic patient with an underlying rheumatic disease indicates a hemophagocytotic syndrome. High dosage steroid should be started before there is biopsy confirmation of the disease.