Duplex screening as a method of quality assurance of perioperative thromboembolism prophylaxis.

BACKGROUND: Improvements in thrombosis prophylaxis in both the operative and non-operative fields aim to reduce further the not inconsiderable residual risk of suffering a deep vein thrombosis or embolism. The goal of the study was to establish the part played in a quality assurance strategy by early diagnosis of a thrombosis and by knowledge of the hospital's internal patient-risk profile in order to counter the unpredictability of thromboembolic complications and make rational decisions about thromboembolism prophylaxis. METHODS: Duplex ultrasonography has been used routinely in trauma surgical patients in Krefeld Hospital since September 1991 as a screening method for diagnosing deep leg and pelvic vein thrombosis prior to mobilisation of the patients. 778 patients were investigated up to March 1997. In the period from September 1991 to September 1994, patients received standardised low-dose prophylaxis with unfractionated heparin (UFH). In October 1994, the prophylaxis regimen was modified by changing the anti-embolism stockings from bidirectional elastic stockings to transverse elastic graduated compression stockings (TED) and by adapting the dosage of the heparin prophylaxis to patient risk, with the use of low molecular weight heparin (LMWH) Certoparin (Mono-Embolex NM) since April 1995. All patients with a deep vein thrombosis were treated immediately with APTT-monitored full heparinisation and immobilisation. RESULTS: In the period from September 1991 to March 1997, an asymptomatic deep vein thrombosis of the lower limbs was diagnosed in 68 cases (8.7%) out of 778 trauma surgical patients by means of routine duplex ultrasound. Using a strategy of duplex screening and immediate anticoagulation/immobilisation, no clinically significant pulmonary emboli occurred in this period. At the same time, the antithrombotic efficacy of the prophylaxis could be improved and assessed objectively by means of duplex screening: with optimal compression stockings and consistent use of risk-adapted UFH prophylaxis, it was possible to reduce the residual thrombosis rate, which was 11.5% (95% CI 7.7-15.2%) with standard UFH prophylaxis, to 8.7 % (95% CI 4.5-12.9%) and ultimately, using the combination of optimal anti-embolism stockings and LMWH prophylaxis, to 6.0% (95% CI 3.0-8.9%) which was significant (p<0.05). The cost-effectiveness analysis resulted in a cost-relation per successfully treated patient of about 1:100 for the diagnosis of a deep vein thrombosis using duplex ultrasound and subsequent heparin treatment compared to the diagnosis and intensive care treatment of a massive pulmonary embolism. CONCLUSIONS: Duplex ultrasound screening for asymptomatic deep vein thrombosis thus proves to be a suitable instrument for internal hospital quality control in thrombosis prophylaxis. Its routine use can be recommended at least in high-risk patients, not only from the medicolegal aspect but also from the purely economic aspect.

Correlation of MRI and arthroscopic diagnosis of knee pathology in children and adolescents.

The accuracy of magnetic resonance imaging (MRI) in diagnosing knee pathology in the pediatric and adolescent population is not well established. The purpose of this study was to correlate the findings of MRI and knee arthroscopy in children and adolescents. One hundred and eight consecutive knee arthroscopies performed in patients ages 4-17 years between 1992 and 1996 were retrospectively reviewed. Fifty-three of these patients underwent preoperative MRI. Age-related comparisons were then made between MRIs and observed intraoperative meniscal and anterior cruciate ligament pathology. The pediatric group (ages 4-14 years) was demonstrated to have an appreciable decrease in sensitivity, specificity, positive predictive value, and accuracy for essentially all categories of pathologic changes. Conversely, negative predictive values for the pediatric group exceeded those of the adolescent group (ages 15-17 years) in each category. The ability of MRI to predict intraarticular knee pathology among adolescents is comparable to that in adults, whereas it is much less accurate in the pediatric population.

An unusual cause of low back pain. Osteomyelitis of the spinous process.

STUDY DESIGN: A case report of osteomyelitis of the spinous process. OBJECTIVE: To describe the diagnosis and successful treatment of a patient with spinous process osteomyelitis. SUMMARY OF BACKGROUND DATA: Spinous process osteomyelitis is exceedingly rare and may be misdiagnosed as paraspinal muscle strain, discitis, or vertebral body osteomyelitis. The clinical presentation of spinous process osteomyelitis is subtle, laboratory findings are nonspecific, and radiographs are often normal. METHODS: The diagnosis, treatment, and outcome of two patients with spinous process osteomyelitis (an adult and a child) with insidious, nonspecific lumbar pain and fever are reviewed. RESULTS: Magnetic resonance imaging with and without gadolinium enhancement demonstrated increased signal of the spinous process with paraspinous musculature enhancement, a finding consistent with spinous process osteomyelitis. Biopsy results demonstrated the presence of staphylococcus aureus in the child and no organisms in the adult. Treatment with intravenous antibiotics led to resolution in both cases. CONCLUSIONS: The use of magnetic resonance imaging technology permitted the early and accurate diagnosis of spinous process osteomyelitis.

Laser induced fluorescence identification of sinoatrial and atrioventricular nodal conduction tissue.

UNLABELLED: Transcatheter ablation of nodal tissue is used for the treatment of arrhythmia resistant to medical therapy. We have investigated the use of laser induced fluorescence spectroscopy for the in vitro recognition of nodal conduction tissue. Twelve fresh human necropsy specimens (< 48 hours) were obtained from sinoatrial node and atrioventricular node areas. Spectra were recorded during excitation at 308 nm (XeCl excimer laser, 1.5-2.0 mJ/pulse, 10 Hz). Ech area examined was marked for subsequent histologic examination. Four hundred eleven spectra were obtained, of which 37 contained nodal conduction tissue (21 sinoatrial, 16 atrioventricular node). Normalized fluorescence emission intensity from these areas was compared with that of surrounding endomyocardial tissue at 18 wavelengths and 35 ratios of fluorescence intensity at selected wavelengths. Spectra recorded from nodal tissue could be clearly distinguished by a visible decrease in fluorescence emission intensity at wavelengths from 440 to 500 nm (P < 0.0006 at 450 nm), peak area, and peak width when compared to that of adjacent atrial endomyocardial tissue. Nodal conduction tissue was also distinguished from ventricular endocardium (14 spectra) by an increase in fluorescence emission at 430 to 550 nm (P < 0.0001). The specificity was 73% and 88% and the sensitivity was 73% and 60% for sinus nodal and atrioventricular nodal conduction tissue identification, respectively. A ratio of fluorescence emission intensity > 1.3 for 380/475 nm was able to detect nodal conduction tissue (P < 0.001). CONCLUSION: Laser induced fluorescence can differentiate nodal conduction tissue from atrial and ventricular endocardium and may provide a new diagnostic tool for the recognition and subsequent ablation of nodal conduction tissue.

Functional expression of the rat brown adipose tissue uncoupling protein in Saccharomyces cerevisiae.

The uncoupling protein (UCP) from mammalian brown adipose tissue is an integral component of the mitochondrial inner membrane where it dissipates the proton electrochemical gradient. UCP is transported into mitochondria from the cytosol but lacks a cleavable targeting peptide. We have expressed the rat UCP in Saccharomyces cerevisiae and shown that this protein, which is not normally found in yeast, is targeted to the mitochondria where it disrupts mitochondrial function, probably by uncoupling oxidative phosphorylation. The observed growth defect is dependent upon the level of expression of UCP. When the unmodified UCP cDNA is expressed in yeast under the control of the GAL10 promoter no defect in growth is observed. We have inserted the UCP coding sequence behind the strong phosphoglycerate kinase promoter under the control of the GAL1-10 upstream activation site and introduced a yeast consensus sequence (ATAATG) at the translation start site. We have found that UCP expressed in S. cerevisiae is targeted to mitochondria and that its expression induces a marked growth defect on non-fermentable carbon sources in a manner dependent on induction with galactose.

Laser-induced fluorescence emission: I. The spectroscopic identification of fibrotic endocardium and myocardium.

UNLABELLED: Laser-induced fluorescence has been developed as a guidance system for laser angioplasty. Laser ablation has been used for resection of arrhythmogenic ventricular scar. We have investigated the use of laser-induced fluorescence for the detection of fibrotic and ischemic changes in endocardium and myocardium. Fluorescence emission spectra from human necropsy specimens were correlated with histologic examination. Normalized fluorescence intensity detected from both the endocardial and the myocardial surfaces of the fibrotic ventricular specimens was significantly higher than that of corresponding normal specimens at 440 to 475 nm. Fibrotic endocardium could be identified by a fluorescence emission intensity ratio less than 1.5 for wavelength ratio 375/450nm. Acutely infarcted endocardium was recognizable by a ratio of 1.5 to 2.0. The specificity and sensitivity of detection of scarred endocardium was 70 and 100%, respectively. Fibrotic myocardium was also consistently identified by fluorescence spectroscopy. CONCLUSION: Fluorescence emission spectroscopy can differentiate normal and fibrotic endocardium and myocardium, in vitro. This technique may be useful for guidance during laser ablation of arrhythmogenic ventricular scar.

Two genes encode the adenine nucleotide translocator of maize mitochondria. Isolation, characterisation and expression of the structural genes.

Southern blot hybridisation of maize (Zea mays) genomic DNA with a specific cDNA probe and sequence analysis of several cDNAs have revealed that the mitochondrial adenine nucleotide translocator (ADP/ATP carrier) is encoded by two genes, both of which are expressed in dark-grown coleoptile tissue. The structural genes (designated ANT-G1 and ANT-G2), encoding the two translocator polypeptides, have been isolated from a maize genomic library and characterised by DNA sequence analysis, mung bean nuclease mapping and primer extension. The two genes each contain two introns and encode very similar proteins. Transcripts from both genes have long (approximately 200 nucleotides) 5' untranslated leaders which are unusual in that they contain several ATG codons upstream of the initiation codon. Transcript analysis of RNA extracted from serial sections of developing maize leaves reveals that the translocator genes are most actively transcribed in the basal meristem, while transcripts were undetectable in green leaves.

Plastid changes during the conversion of chloroplasts to chromoplasts in ripening tomatoes.

Methods were developed for the isolation of plastids from mature green and ripening tomatoes (Lycopersicon esculentum Mill.) and purification by sucrose or Percoll density-gradient centrifugation. Assessment of the purity of preparations involved phase-contrast and electron microscopy, assays for marker enzymes and RNA extraction and analysis. Proteins were extracted from isolated plastids at different ripening stages and separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The profiles obtained from chloroplasts and chromoplasts showed many qualitative and quantitative differences. Labelling of proteins with [(35)S]methionine in vivo showed that there was active protein synthesis throughout ripening, but there was a change in the plastid proteins made as ripening proceeded. The cellular location of synthesis of specific proteins has yet to be established.