Relation between energy expenditure and body composition in man: specific energy expenditure in vivo of fat and fat-free tissue

The relationship between energy expenditure and body composition, in terms of fat and fat-free masses, has previously been described by a variety of predictive regression equations with parameters devoid of physiological content. We present here results obtained by calculating the specific energy expenditure, ie, the energy expenditure per unit of mass, of fat and fat-free tissue on the basis of measurements of the total energy expenditure (EE), the masses of fat (FM), and fat-free (FFM) tissue using the following simple model: EE = k1.FM + k2.FFM where k1 and k2 are the specific energy expenditures of fat and fat-free tissue, respectively. The results of observations on 104 women at rest yielded values for k1 and k2 of 0.31 and 1.35 watts/kg of fat and fat-free mass, respectively, with standard errors of estimate of 0.074 and 0.052 watts/kg, respectively. Analysis of several series of measurements, from other sources and on smaller samples of subjects, yielded similar values at rest but with larger standard errors of estimate. Data from subjects performing varying amounts of work in 24-h measurements showed, as expected, larger values for both tissues. The results explain to a very large extent the well-established relation between resting metabolic rate and body weight, ie, a linear relation with a non-zero intercept. The results also offer a clear-cut explanation for the well known difference in energy expenditure between men and women with the same body weight.     

Factors associated with the quality of laboratory performance in the United Kingdom external quality assessment scheme for serum growth hormone

A search was made for associations between poor performance in the UK External Quality Assessment Scheme (EQAS) for serum growth hormone (GH), and a range of factors including assay method, laboratory workload and staffing, and Internal Quality Control (IQC) procedures. On the basis of the factors identified as being associated with poor performance we recommend the following. 1. Laboratories using RIA for GH should routinely analyse samples at two dilutions and report a mean result. 2. The use of 125I-GH which is 5 or more weeks old should be avoided. Tracer should also be chromatographed to remove aggregate before use. 3. Laboratories using RIA should avoid using a standard curve which covers too wide a range concentration; a curve midpoint (ie GH concentration to reduce the zero standard binding by 50%) of about 8 mU/l or less is probably acceptable. 4. It should be noted that high workloads present a risk of some loss in quality of responsible for checking IQC data. 6. Laboratories which do not have the resources to maintain fully their own RIA as outlined above should carefully consider use of an unbiased, precise IRMA. The UK EQAS has identified two assays (Boots-Celltech Sucrosep, NETRIA) that appear to meet these criteria [2]. The above observations may also be relevant to immunoassays for other peptide hormones.     

The origin and nature of stromal osteoclast-like multinucleated giant cells in breast carcinoma: implications for tumour osteolysis and macrophage biology

The origin and nature of osteoclast-like multinucleated giant cells (OMGCs), in extraskeletal neoplasms, is uncertain. The ultrastructure, antigenic phenotype and function of OMGCsm in a breast carcinoma were studied in order to clarify the relationship between OMGCs, osteoclasts and other cells of the mononuclear phagocyte system (MPS). OMGCs resorbed cortical bone in a manner similar to osteoclasts. However, unlike osteoclasts, OMGCs did not possess a ruffled border or clear zone, and expressed HLA-DR and Fc receptors and CD14, CD16, CD18 and CD11 (p150,95) antigens. In addition, OMGCs failed to respond morphologically to calcitonin and were directly stimulated by parathyroid hormone (PTH) to increase bone resorption. These findings suggest that OMGCs are a specific type of macrophage polykaryon distinct from both osteoclasts and other types of inflammatory polykaryon. Occasional smaller (20-25 microns) macrophage-like cells were also associated with resorption pits. Bone resorption by OMGCs isolated from the breast indicates that a cell of the MPS can be transplanted to a new tissue location and perform a highly specialised function appropriate to an MPS cell of that tissue (i.e. the osteoclast). PTH stimulation of bone resorption by OMGCs suggests that PTH or a PTH-like protein, may be involved in the bone resorption and consequent hypercalcaemia associated with metastatic breast cancer.     

Percutaneous Endovascular Treatment for Stenoses and Occlusions of Infrarenal Aorta and Aortoiliac Bifurcation: Midterm Results

OBJECTIVE: evaluation and comparison of the endovascular treatment of isolated aortic and aortoiliac atherosclerotic lesions (stenoses and occlusions). METHODS: a percutaneous endovascular procedure was performed in 52 patients (38 men and 14 women) with a mean age of 52 years (range, 25-85 years). The baseline angiogram showed 35 aortic lesions (31 stenoses, 4 occlusions) and 17 aortoiliac lesions (14 stenoses, 3 occlusions). Percutaneous techniques used in this series included variable combinations of transluminal angioplasty and stenting. All stents placements were performed over-the-wire using the transfemoral route (most often bilateral approach). Clinical examination and Duplex-scan were performed at discharge, 1 month, 6 months, 12 months, and then yearly. RESULTS: technical success was 100% for aortic and aortoiliac lesions. Angiographic success rates were comparable for aortic (91%) and aortoiliac (94%) lesions. No death occurred during or early after the endovascular intervention. Duplex-scan confirmed 100% patency rate at discharge. There was no significant difference between the aortic (94%) and aortoiliac (96%) groups regarding immediate clinical improvement. Mean follow-up was 34+/-31 months (range, 0-130 months). The cumulative primary patency rate at 36 months was 85% in the aortic group and 86% in the aortoiliac group. Clinical success, defined as a symptom-free status at the end of follow-up, was also similar in both groups. CONCLUSION: endovascular treatment of isolated aortic lesions of the infra-renal aorta has favorable outcomes comparable to those of aortoiliac lesions.     

Beeinflussung humaner Osteoblasten durch verschiedene Analgetika

In der Behandlung von Frakturen spielt die Analgesie eine wesentliche Rolle. Es stellt sich daher die Frage, ob in der Klinik h?ufig eingesetzte Analgetika wie Tramadol oder Diclofenac negative Wirkungen auf die Knochenbruchheilung haben.     

Surgical management of bile duct injuries following laparoscopic cholecystectomy: analysis and follow-up of 28 cases

BACKGROUND: Biliary tract lesions pose a dreaded complication of laparoscopic cholecystectomy. In a retrospective study we analyzed the clinical presentation, diagnostic and therapeutic management and outcome of 28 patients presenting with iatrogenic bile duct injuries. PATIENTS AND METHODS: Between 1994 and 2001 we treated 28 patients with bile duct lesions following laparoscopic cholecystectomy at our center. Operation notes and charts of all patients were reviewed systematically. A follow-up examination of each patient was performed after a median of 12 months (range 1-90). RESULTS: Twenty-two patients presented with major circumferential bile duct defect lesions. Less severe injuries (n=6) were two minor bile leaks, one bile duct stricture and three tangential lesions. Twenty-six patients were referred to our institution within 16 days (range 0-226 days). Six patients were treated by nonsurgical procedures: endoscopic stenting in four and percutaneous intervention in two. In one of the remaining patients a cystic duct leak was closed via laparotomy, and in 21 a hepaticojejunostomy was performed. Reconstruction of a hepaticojenunostomy was performed in two of these patients. Patients were dismissed from the hospital after a median of 13 days (range 4-156). Four patients presenting with generalized biliary peritonitis required prolonged intensive care. One or more episodes of cholangitis were seen in five patients during follow-up examinations. CONCLUSIONS: Major iatrogenic bile duct injuries are associated with high morbidity and prolonged hospitalization. Interdisciplinary cooperation and early referral to an experienced center is crucial in the management of patients suffering from this affliction. Cholangitis is a marked problem in the follow-up.     

Erythropoietin production in healthy volunteers subjected to controlled hypobaric hypoxia: further evidence against a role for adenosine

Aims Objective of this study was to investigate whether adenosine modulates renal erythropoietin production.
Methods In the present study erythropoietin production was stimulated by hypobaric hypoxia by subjecting healthy volunteers to a simulated altitude of 4000  m in a low pressure chamber for 5.5  h. During exposure to hypoxia the subjects received i.v. in a randomized, single-blind, cross-over fashion the non-specific adenosine antagonist theophylline, the adenosine reuptake inhibitor dipyridamole and placebo.
Results Contrary to the working hypothesis, theophylline did not decrease and dipyridamole did not further boost erythropoietin concentrations.
Conclusions The results are in agreement with our earlier study using haemorrhage as a controlled physiological stimulus of erythropoietin production, and would question a major role for adenosine as a mediator of renal erythropoietin production.     

Stereoselectivity of actions of the calcium sensitizer [+]-EMD 60263 and its enantiomer [-]-EMD 60264

The thiadiazinone derivative [+]-EMD 60263 ((+)-5-(1-(α-ethylimino-3,4-dimethoxybenzyl)-1,2,3,4- tetrahydroquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4 -thiadiazine-2-on) is a Ca²⁺-sensitizing agent with only minor phosphodiesterase inhibitory activity. Our aim was to characterize the inotropic and electrophysiological effects of [+]-EMD 60263 and its enantiomer [-]-EMD 60264 in several cardiac muscle preparations. The Ca²⁺-sensitizing activity resided in the [+]-enantiomer only. [+]-EMD 60263 (3 μM) shifted the EC₅₀ of Ca²⁺ for contractile activation of skinned fibers of pig heart from 2.41 μM to 0.73 μM, whereas [-]-EMD 60264 (30 μM) was ineffective. In Langendorff-perfused guinea pig hearts, [+]-EMD 60263 and [-]-EMD 60264 induced concentration-dependent positive and negative inotropic effects, respectively; both enantiomers reduced spontaneous heart rate but did not influence perfusion pressure. The maximum increase in force of human atrial trabeculae was 35 % of pre-drug control with [+]-EMD 60263 in comparison to 113 % with forskolin. In guinea-pig papillary muscles, [+]-EMD 60263 and [-]-EMD 60264 had opposite inotropic responses, however, both agents similarly prolonged action potential duration. Both enantiomers concentration-dependently blocked the rapidly activating component I_Kr of the delayed rectifier in guinea-pig myocytes. The block saturated at potentials positive to +30 mV, closely resembling the effects of the antiarrhythmic agent E-4031 which had been originally used to define I_Kr. It is concluded, that the positive inotropic action of [+]-EMD 60263 can be explained by prevalence of the Ca²⁺-sensitizing effect. The accompanying prolongation in action potential duration is caused by block of the I_Kr component of the delayed rectifier. While the inotropic effects are stereoselective, most of the electrophysiological actions are clearly independent of sterical configuration. The combination of Ca²⁺-sensitizing with class-III antiarrhythmic action may provide an interesting pharmacological profile of potential therapeutic use. Received: 7 January 1997 / Accepted: 25 February 1997