Biomedical subjects

A Engel

Publications and source records attributed to A Engel.

At least 19 recordsLinked to original sources

PubMed2007

Influence of high tibial osteotomy on bone marrow edema in the knee.

To determine the influence of high tibial osteotomy on subchondral bone marrow edema in medial osteoarthritis of the varus knee, full leg-length radiographs and magnetic resonance imaging were performed in 20 patients (20 knees) before surgery, 1 year postoperatively, and at a mean of 7 years postoperatively. The extent of bone marrow edema in the medial compartment was quantified with magnetic resonance imaging in two planes using the formula for a prolate ellipsoid as follows: length x width x depth x pi/6. We used the Japanese Orthopaedic Association knee score for clinical evaluation. At the last followup, all knees with valgus alignment (10/10) showed reduced edema. In contrast, bone marrow edema increased or remained unchanged in four of 10 knees with neutral or varus alignment. The percentage of satisfactory results was 100% (10/10) in valgus knees and only 30% (3/10) in neutral or varus knees. Extent of bone marrow edema at the followup correlated with the mechanical axis and knee score. Because of the prognostic value of bone marrow abnormalities in the medial compartment observed on magnetic resonance imaging, early lateral closing wedge osteotomy should be considered in patients with varus malalignment and bone marrow edema even in mild cases of medial osteoarthritis.

Adult↗

PubMed2006

Cilostamide potentiates more the positive inotropic effects of (-)-adrenaline through beta(2)-adrenoceptors than the effects of (-)-noradrenaline through beta (1)-adrenoceptors in human atrial myocardium.

Activation of both beta(1)- and beta(2)-adrenoceptors increases the contractility of human atrial myocardium through cyclic AMP-dependent pathways. Cyclic AMP is hydrolised by phosphodiesterases, but little is known about which isoenzymes catalyse inotropically relevant cyclic AMP accumulated upon stimulation of beta-adrenoceptor subtypes. We have compared the positive inotropic effects of (-)-noradrenaline and (-)-adrenaline, mediated through beta(1)- and beta(2)-adrenoceptors, respectively, in the absence and presence of the PDE3 inhibitor cilostamide (300 nM) or PDE4 inhibitor rolipram (1 muM) on human atrial trabeculae from non-failing hearts. Cilostamide, but not rolipram, potentiated the effects of both (-)-noradrenaline and (-)-adrenaline. Cilostamide increased the -logEC(50)M of (-)-adrenaline more than of (-)-noradrenaline (P < 0.05), regardless of whether or not the patients had been chronically treated with beta-blockers. The results are consistent with a greater PDE3-catalysed hydrolysis of inotropically relevant cyclic AMP produced through beta(2)-adrenoceptors than beta(1)-adrenoceptors in human atrium.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2006

The effects of propofol on neutrophil function, lipid peroxidation and inflammatory response during elective coronary artery bypass grafting in patients with impaired ventricular function.

BACKGROUND: Coronary artery bypass grafting (CABG) with cardiopulmonary bypass elicits a potent reperfusion injury and inflammatory response, more intense in patients with impaired myocardial function. Propofol has antioxidant properties which may attenuate such a response. METHODS: In total, 27 patients with impaired left ventricular function undergoing CABG were randomly allocated to receive either target-controlled infusion propofol (P) or saline (S) immediately before aortic cross-clamp release until 4 h after reperfusion. Troponin-I, Urinary 8-epi PGF-2alpha isoprostane, coronary sinus and systemic malondialdehyde concentrations, Interleukin-6 (IL-6), -8 and -10 concentrations and leucocytes function studies (neutrophil respiratory burst, phagocytosis, CD-11b and CD-18 expression) were measured. RESULTS: Propofol decreased MDA coronary sinus concentration at 1, 3 and 5 min after reperfusion (P<0.01); 60 min after reperfusion a significant difference between the two groups in systemic MDA concentrations was also seen. IL-6 concentration increases were significantly greater in Group S than Group P, 4 h after reperfusion [1118 (1333) pg ml(-1) vs 228 (105) pg ml(-1), P<0.01]. Serum IL-8 concentrations did not increase significantly in either group. Compared with baseline values IL-10 concentrations decreased after reperfusion but the values were higher in the propofol group than in the control group [22 (16) vs 11 (4) pg ml(-1), P<0.05]. No difference in leucocyte function or urinary isoprostane concentrations was demonstrated. CONCLUSION: Propofol attenuates free-radical-mediated lipid peroxidation and systemic inflammation in patients with impaired myocardial function undergoing CABG.

Aged↗

PubMed2006

The influence of propofol on the expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) in reoxygenated human umbilical vein endothelial cells.

BACKGROUND: Leucocytes are a pivotal component of the inflammatory cascade that results in tissue injury in a large group of disorders. Free radical production and endothelial activation promote leucocyte-endothelium interactions via endothelial expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) which augment these processes, particularly in the setting of reperfusion injury. Propofol has antioxidant properties which may attenuate the increased expression of these molecules that is observed. METHODS: Cultured human umbilical vein endothelial cells were exposed to 20 h of hypoxia, then returned to normoxic conditions. Cells were treated with saline, Diprivan 5 microg mL(-1) or propofol 5 microg mL(-1), for 4 h after reoxygenation and were examined for ICAM-1 and VCAM-1 expression. RESULTS: Hypoxia did not increase the expression of ICAM-1/VCAM-1. ICAM-1 expression peaked 12 h after reoxygenation (21.75(0.6) vs. 9.6(1.3), P = 0.02). Propofol, but not Diprivan, prevented this increase (8.2(2.9) vs. 21.75(0.6), P = 0.009). VCAM-1 expression peaked 24 h after reoxygenation (9.8(0.9) vs. 6.6(0.6), P = 0.03). Propofol and Diprivan prevented this increase, with no difference between the two treatments observed (4.3(0.3) and 6.4(0.5) vs. 9.8(0.9), P = 0.001, 0.02, respectively). CONCLUSION: These effects are likely to be attributable to the antioxidant properties of propofol, and suggest that propofol may have a protective role in disorders where free radical mediated injury promotes leucocyte-endothelium adhesive interactions.

Analysis of Variance↗

PubMed2006

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.

Antioxidants↗

PubMed2006

Elongated eccentric soft coronary plaque: major diagnostic pitfall on quantitative coronary angiography overpowered by computed tomography coronary angiography and intravascular ultrasound.

We describe a significant left anterior descending coronary lesion in a patient with unstable angina pectoris. This lesion was erroneously underestimated using quantitative coronary angiography; however, CT coronary angiography correctly showed a significant, elongated, eccentric, soft plaque that was later confirmed by repeated quantitative coronary angiography with intravascular ultrasound. As showed, CT coronary angiography may offer a reliable non-invasive alternative to quantitative coronary angiography and intravascular ultrasound by enabling a true 3-D coronary lumenogram combined with plaque detection and characterization.

Angioplasty, Balloon, Coronary↗

PubMed2006

Comprehensive multidetector CT assessment of apical hypertrophic cardiomyopathy.

16-slice multidetector CT (MDCT) cardiac findings of a middle-aged man with known apical hypertrophic cardiomyopathy (AHC) and recent atypical chest pain are presented. MDCT enabled comprehensive evaluation of the coronary arteries, diagnosing myocardial bridging of the left anterior descending (LAD) and first diagonal arteries. It also enabled dynamic evaluation of myocardial thickness and left ventricular global and regional function. This case illustrates the full capabilities of MDCT in the evaluation of AHC.

Adult↗

PubMed2005

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.

Animals↗

PubMed2005

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.

Air Pollutants, Occupational↗

PubMed2005

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.

Journal Article↗

PubMed2005

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.

Adolescent↗

PubMed2005

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.

Aged↗

PubMed2004

[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.

Abortion, Habitual↗

PubMed2004

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.

Adult↗

PubMed2004

[Bilateral cochlea implantation in varying duration of deafness].

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.

Aged↗

PubMed2004

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.

Bacillus subtilis↗

PubMed2004

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.

Anastomosis, Surgical↗

PubMed2004

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.

Adult↗