Biomedical subjects
B Hesse
Publications and source records attributed to B Hesse.
The initial domestication of goats (Capra hircus) in the Zagros mountains 10,000 years ago.
Initial goat domestication is documented in the highlands of western Iran at 10,000 calibrated calendar years ago. Metrical analyses of patterns of sexual dimorphism in modern wild goat skeletons (Capra hircus aegagrus) allow sex-specific age curves to be computed for archaeofaunal assemblages. A distinct shift to selective harvesting of subadult males marks initial human management and the transition from hunting to herding of the species. Direct accelerator mass spectrometry radiocarbon dates on skeletal elements provide a tight temporal context for the transition.
Myocardial perfusion scintigraphy as a screening method for significant coronary artery stenosis in cardiac transplant recipients.
BACKGROUND: Several studies have explored the feasibility of using myocardial perfusion imaging to detect allograft vasculopathy after heart transplantation. We undertook the present prospective consecutive study to comparatively evaluate the role of serial myocardial perfusion single-photon emission computed tomography (SPECT) scanning and coronary arteriography (CAG) in detecting coronary artery stenosis suitable for coronary angioplasty in heart transplant recipients. METHODS: Within a 2-week interval during a follow-up period of 5.6 (95% confidence limits 2.1 to 12) years, 255 serial CAGs and myocardial perfusion scintigraphies were performed in 67 patients. Arteriography and scintigraphy were performed once yearly after heart transplantation. We retrospectively analyzed the data. RESULTS: Myocardial scintigraphy showed pathologic reversible defects in 9 out of 67 patients. Four of these patients had significant (>50% and also >70%) focal segmental stenosis in the middle and proximal parts of the coronary arteries (Type A lesions), 1 had diffuse and circumferential narrowing in the distal parts (Type B lesions), whereas CAG showed no lesions in the remaining 4 patients. The patients with significant Type A lesions were revascularized with percutaneous coronary angioplasty. Coronary arteriography showed that 1 patient had extensive Type A and Type B lesions, whereas myocardial perfusion scans detected no. The predictive value of a negative (normal) SPECT was 98% (95% confidence limits 94% to 100%) for the detection of lesions suited for revascularization. CONCLUSIONS: Annual myocardial SPECT seems well suited to screen for significant coronary artery stenosis. A SPECT study without reversible defects virtually excludes lesions suitable for coronary artery revascularization.
Scandinavian test of artificial neural network for classification of myocardial perfusion images.
Artificial neural networks are systems of elementary computing units capable of learning from examples. They have been applied to automated interpretation of myocardial perfusion images and have been shown to perform even better than experienced physicians. It has been shown that physicians interpreting myocardial perfusion images benefit from the advice of such networks. These networks have been developed and validated in the same hospital. However, widespread use of neural networks will only take place if the networks can maintain a high accuracy in other hospitals, i.e. hospitals using different gamma cameras, different acquisition techniques, different study protocols, etc. The purpose of this study was to develop a neural network in one hospital and test it in another. An artificial neural network was trained to detect coronary artery disease using myocardial perfusion scintigrams from 135 patients at a Swedish hospital. Thereafter, this network was tested using scintigrams from 68 patients at a Danish hospital and compared to six criteria based on expert physician analysis and quantitative analysis by the CEqual program. The sensitivity of the network was significantly higher than that of one of the physician criteria (0. 92 versus 0.71) and two of the CEqual-based criteria (0.94 versus 0. 63 and 0.96 versus 0.65) compared at equal specificities. It was concluded that an artificial neural network can maintain high accuracy in a hospital other than the one where it was developed.
[Pattern of injuries and prophylaxis in paragliding].
This study will present trends and recommendations to increase active and passive safety in paragliding on the basis of current state-of-the-art equipment and typical patterns of injury. This German-Swiss teamwork presents data of 55 male and 9 female patients treated after paragliding accidents between 1994 to 1998 respectively 1996 to 1998. 43.7% of the pilots presented with multiple injuries, 62.5% suffered spinal fractures and 18.8% pelvic fractures. 28.4% of the injured pilots were admitted with injuries of the lower extremities mainly affecting the tarsus or the ankle joint. Only three patients with single injuries could be treated in an ambulatory setting. 54.0% of the injuries left the patients with lasting functional residues and complaints. Main causes of accidents were either pilot error in handling the paraglider or general lack of awareness about potential risk factors. 46.0% of injuries occurred during landing, 42.9% of injuries during the flight and another 11.1% of injuries during starting procedures. With noticeable enhanced performance sails of the beginners and intermediate level are increasingly popular. Protective helmets and sturdy footwear reaching above the ankle joint are indispensable pieces of equipment. The use of protective gloves is highly recommended. Back protection devices of the new generation provide the best passive prophylaxis for the pilot against pelvic and spinal cord injuries. This area hold the most promise for increasing safety and reducing risk of injury in future, apart from using beginners and intermediate wings. After acquisition of the pilot license performance and security training provide the best preparing to master unforeseeable situations.
Extraosseous accumulation of Tc-99m diphosphonate.
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[Cardiac scanning with positron emission tomography--PET. Clinical use and research aspect].
Assessment of regional myocardial glucose metabolism and regional myocardial perfusion has become possible with positron emission tomography (PET). These parameters are of importance in distinguishing viable from fibrotic myocardium in patients with ischaemic heart disease. PET scanning appears to be the method of choice in these patients, which has led to an increased clinical application of PET as a method usable to select patients with severe heart disease before potential revascularisation. In the present review, PET technology is briefly described, together with an overview of the scientific evidence supporting the clinical application of cardiac PET. Finally, its applications in the fields of pathophysiology and pharmacology are briefly described.
Trends in myocardial perfusion single-photon emission technique.
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Human bronchial artery blood flow after lung Tx with direct bronchial artery revascularization.
The inaccuracy of measuring human bronchial artery blood flow has previously been considerable. En bloc double-lung transplantation with bronchial artery revascularization (BAR) using a single conduit offers the unique opportunity of direct measurement of the total bronchial artery blood flow. In eight en bloc double-lung-transplanted patients with complete BAR, the basal blood flow was measured by using a 0.014-in. Doppler guide wire and arteriography. The average peak velocity in the conduit was 12-73 cm/s [+/-2.1 (SD) cm/s], and the conduit diameter was 1.7-3.1 mm [+/-0.10 (SD) mm], giving individual basal flow values between 19 and 67 ml/min [+/-5 (SD) ml/min], or 0.2-1.9% of estimated cardiac output. In three patients basal measurements were followed by injection of nitroglycerin and verapamil into the conduit. This increased the bronchial artery flow to 121-262% of basal values (31-89 ml/min). The measured values appear more physiologically plausible than previous bronchial artery blood flow measurements in humans.
Bronchial artery perfusion scintigraphy to assess bronchial artery blood flow after lung transplantation.
UNLABELLED: The bronchial arterial system is inevitably interrupted in transplanted lungs when removing the organs from the donor, but it can be reestablished by direct bronchial artery revascularization (BAR) during implantation. The purpose of this study was to visualize and quantify the distribution of bronchial artery perfusion after en bloc double lung transplantation with BAR, by injecting radiolabeled macroaggregated albumin directly into the bronchial artery system. METHODS: BAR was performed using the internal mammary artery as conduit. Patients were imaged 1 mo (n = 13) or 2 y (n = 9) after en bloc double lung transplantation with BAR. Immediately after bronchial arteriography, 100 MBq macroaggregated albumin (45,000 particles) were injected through the arteriographic catheter. Gamma camera studies were then acquired in the anterior position. At the end of imaging, with the patient remaining in exactly the same position, 81mKr-ventilation scintigraphy or conventional intravenous pulmonary perfusion scintigraphy or both were performed. Images were evaluated by visual analysis, and a semiquantitative assessment of the bronchial arterial supply to the peripheral parts of the lungs was obtained with conventional pulmonary scintigraphy. RESULTS: The bronchial artery scintigraphic images showed that the major part of the bronchial arterial flow supplied central thoracic structures, but bronchial artery perfusion could also be demonstrated in the peripheral parts of the lungs when compared with conventional pulmonary scintigraphy. There were no differences between scintigrams obtained from patients studied 1 mo and 2 y post-transplantation. CONCLUSION: Total distribution of bronchial artery supply to the human lung has been visualized in lung transplant patients. This study demonstrates that this nutritive flow reaches even the most peripheral parts of the lungs and is present 1 mo as well as 2 y after lung transplantation. The results suggest that bronchial artery revascularization may be of significance for the long-term status of the lung transplant.
[Myocardial scintigraphy in Denmark].
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[Development of myocardial scintigraphy, coronary arteriography and revascularization techniques in Denmark during the last five years].
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Risk of atrioventricular block during adenosine pharmacologic stress testing in heart transplant recipients.
Pharmacologic stress testing with adenosine in heart transplant recipients implies a high risk of atrioventricular block. Dipyridamole is preferable as a coronary vasodilator.
[Risk factors for the development of asthma in children and adolescents. Results of a longitudinal study].
To investigate risk factors for the development of asthma, a population sample of children and adolescents, aged 7 to 17 yrs at enrollment, were studied twice, with a six year interval; complete data was available for 408 subjects (199 males). Obtained case history was used to assess the presence of asthma; pulmonary function, skin prick test reactivity, total serum IgE and bronchial responsiveness to inhaled histamine (BHR) were measured using standard techniques. The 12-month period prevalence of asthma increased significantly from the first to the second examination in both males (p < 0.001) and females (p < 0.001), whereas the number of subjects with a positive histamine challenge test declined in both sexes. The prevalence of a positive skin prick test was higher at the second examination (26% and 44%, respectively, p < 0.001); the proportion of subjects with a positive skin reaction to house dust mite (HDMpos) increased from 14% to 26%. Confining the analysis to subjects without a history of asthma at the first examination showed that asymptomatic BHR (Odds Ratio [OR] 3.8 [95% Confidence Interval (CI) 2.5-5.1], p = 0.0002), HDMpos (OR 2.6 [CI 1.9-3.3], p = 0.005), a history of wheezy bronchitis before the age of two yrs (OR 3.8 [CI 2.4-5.2], p = 0.006) and a history of rhinitis and/or eczema (OR 2.8 [CI 1.7-3.9], p = 0.007) at first examination were associated with an increased risk for development of symptomatic asthma at some point between the two examinations. No significant relationship could be demonstrated between smoking (passive or active) and the risk for development of asthmatic symptoms. In conclusion, this longitudinal population study showed an increase in the 12-month period prevalence of asthma with sensitization to HDM and asymptomatic BHR as important risk factors for development of asthma.
Continuous monitoring of global left ventricular ejection fraction during percutaneous transluminal coronary angioplasty.
Continuous monitoring of left ventricular (LV) function during percutaneous transluminal coronary angioplasty (PTCA) was performed in 40 patients (53 +/- 2 years) with a miniature, nuclear detector system after labeling the patients' red blood cells with technetium-99m. Balloon dilation (113 seconds, range 60 to 240) induced on average a 0.12 ejection fraction (EF) unit (19%) decrease in the LVEF, which was explained by a 34% increase in end-systolic counts. Balloon dilation of the left anterior descending artery (n = 23) produced a decrease in the LVEF of 0.17 +/- 0.13 EF units compared with the decrease of 0.06 +/- 0.07 EF units in patients undergoing dilation of the left circumflex artery (n = 9) and 0.05 +/- 0.04 EF units in patients treated for a stenosis of the right coronary artery (n = 8), (p = 0.02). Balloon deflation was associated with an immediate return to pre-PTCA levels. In 10 patients with 2 identical balloon occlusions, the second occlusion led to a significantly less decrease in the LVEF (0.41 +/- 0.14 vs 0.44 +/- 0.15) and electrocardiographic ST-segment deviation (88 +/- 54 microV vs 65 +/- 42 microV) than the first. We conclude that PTCA is associated with an abrupt transient decrease in the LVEF. The effect of balloon occlusion of the left anterior descending artery is more pronounced than balloon occlusion of the left circumflex and the right coronary arteries. Neither single nor multiple balloon occlusions were associated with post-PTCA global LV dysfunction, whereas the lesser degree of LV dysfunction and electrocardiographic signs of myocardial ischemia during the second of 2 identical balloon occlusions suggests that preconditioning can be induced during PTCA.
Risk factors for reduced pulmonary function after malignant lymphoma in childhood.
The aim was to study pulmonary function after Hodgkin disease or non-Hodgkin Lymphoma in childhood and to evaluate if younger age at diagnosis and therapy is a risk factor for reduced pulmonary function. We studied a population-based sample of survivors of Hodgkin disease (n = 22) or non-Hodgkin lymphoma (n = 19) in childhood. Pulmonary function test results were compared with reference values for our laboratory, generated by adjusting published reference values fit 348 healthy never-smokers from a local population study. Data were analyses as standardised residuals, which are [observed minus predicted value] divided by the residual standard deviation of the reference equations. At a median of 11 years after diagnosis (range 2 to 24), the participants had significantly reduced lung volumes and transfer factor, unrelated to the few pulmonary symptoms. On average, the total lung capacity was reduced to -0.9 standardised residual and the transfer factor was reduced to -1.3 standardised residual. Young age at therapy seemed to be a risk factor for reduced lung function, especially when treatment included thoracic irradiation. No significant toxic synergism was observed between smoking and previous cancer therapy. Therapy without thoracic irradiation but with doxorubicin and cyclophosphamide was almost as toxic to lung function as therapy with thoracic irradiation but without doxorubicin and cyclophosphamide. In conclusion, lung volumes and transfer factor were reduced several years after childhood Hodgkin disease of non-Hodgkin lymphoma, with young age at therapy as a risk factor, especially when combined with thoracic irradiation.
False-positive defects in technetium-99m sestamibi myocardial single-photon emission tomography in healthy athletes with left ventricular hypertrophy.
Exercise ECG and myocardial single-photon emission tomography (SPET) are fundamental in the non-invasive evaluation of patients suspected of having coronary artery disease (CAD). The purpose of the present study was to investigate the influence of physiological left ventricular hypertrophy (LVH) on myocardial sestamibi SPET in healthy young and old athletes. Eighteen young male elite athletes (ten rowers, five power/weight lifters and three triathletes) and 14 well-trained elderly rowers were studied. All underwent a bicycle test as part of a 2-day sestamibi SPET protocol. Attenuation correction was not performed. The studies were evaluated visually and quantitatively analysed by the CEqual program with its reference files and with a file from a local non-athletic age-matched population. Echocardiographic LVH was an inclusion criterion in the young athletes. Exercise ECG was normal in all subjects. In at least three of the young athletes a reversible defect was observed by visual analysis. On quantitative analysis one-third of the young athletes had "significant" (>10 pixels) defects compared with both the local reference base and the CEqual reference population. Nearly all defects were found in the anterior or inferior wall. The remaining subjects, including all old rowers, had normal SPET findings. Anterior and inferior wall defects are so common in healthy athletes with physiological LVH that the specificity of myocardial SPET, in contrast to exercise ECG, seems to be too low for evaluation of chest pain in this group. The mechanism of anterior and inferior defects may be related to hot spots (papillary muscles?) in the lateral wall. The specificity of SPET is maintained in athletes without LVH.
Fluorodeoxyglucose uptake in dysfunctional myocardium subtended by an occluded coronary artery. Relation to dobutamine contractile reserve and Sestamibi uptake.
BACKGROUND: Myocardial segments with impaired function may have the potential for functional recovery. Augmented exogenous glucose uptake in relation to blood flow estimated by [2-18F]2-fluorodeoxyglucose (FDG) and positron emission tomography (PET) frequently indicates functional reversibility. The spectrum of FDG uptake levels in relation to Sestamibi uptake and dobutamine contraction reserve in areas with impaired function subtended by an occluded coronary artery has never been reported. METHODS AND RESULTS: Seventeen patients with stable angina pectoris and dysfunctional myocardium subtended by an occluded coronary artery were studied with FDG-PET, low-dose dobutamine echocardiography and Sestamibi-Single Photon Emission Computerized Tomography. In a 16 segment model dysfunctional myocardial segments showed a normally distributed FDG uptake ranging from 34% to 150% when normalized to peak segmental Sestamibi uptake. Low FDG uptake was associated with both lack of dobutamine induced contractile reserve and low Sestamibi uptake (in 73% of the segments) whereas high FDG uptake displayed both contractile reserve and Sestamibi uptake (57%). Segments with intermediate FDG uptake had either contractile reserve or a preserved Sestamibi uptake (62%). CONCLUSION: Dysfunctional myocardium subtended by an occluded coronary artery represents a continuum of metabolic states with a high degree of heterogeneity with regard to contractile reserve and Sestamibi uptake.