Whole-body adipose tissue analysis: comparison of MRI, CT and dual energy X-ray absorptiometry.

The aim of this study was to validate a recently proposed MRI-based T(1)-mapping method for analysis of whole-body adipose tissue (AT) using an established CT protocol as reference and to include results from dual energy X-ray absorptiometry (DEXA). 10 subjects, drawn from the Swedish Obese Subjects Sibling-pairs study, were examined using CT, MRI and DEXA. The CT analysis was based on 28 imaged slices. T(1) maps were calculated using contiguous MRI data from two different gradient echo sequences acquired using different flip angles. CT and MRI comparison was performed slice-wise and for the whole-body region. Fat weights were compared between all three modalities. Strong correlations (r > or = 0.977, p<0.0001) were found between MRI and CT whole-body and AT volumes. MRI visceral AT volume was underestimated by 0.79 +/- 0.75 l (p = 0.005), but total AT was not significantly different from that estimated by CT (MRI - CT = -0.61+/-1.17 l; p = 0.114). DEXA underestimated fat weights by 5.23 +/- 1.71 kg (p = 0.005) compared with CT. MRI underestimated whole-body volume by 2.03 +/- 1.61 l (p = 0.005) compared with CT. Weights estimated either by CT or by DEXA were not significantly different from weights measured using scales. In conclusion, strong correlations were found between whole-body AT results from CT, MRI-based T(1) mapping and DEXA. If the differences between the results from T(1)-mapping and CT-based analysis are accepted, the T(1)-mapping method allows fully automated post-processing of whole-body MRI data, allowing longitudinal whole-body studies that are also applicable for children and adolescents.

Measurement of lower-leg volume change by quantitative computed tomography.

BACKGROUND: Lower-leg edema is a common symptom in many diseases. A precise method with low variability for measurement of edema is warranted in order to obtain optimal conditions for investigation of treatment effects. PURPOSE: To evaluate computed tomography for precise measurement of lower-leg muscle and adipose tissue volumes using a very low level of effective radiation dose. MATERIAL AND METHODS: Eleven volunteers were examined three times during 1 day, either as two consecutive examinations in the morning and one single examination in the afternoon, or as one examination in the morning and two in the afternoon. Eleven scans with computed tomography were made at each examination, and lower-leg volumes were calculated from automatically measured scan areas and interscan distances. Volumes for muscle, adipose tissue, and bone were calculated separately. Minimal radiation dose was used. RESULTS: Mean difference between the repeated examinations was -0.1 ml for total volume, -1.4 ml for muscle, and 1.6 ml for adipose tissue volume. The corresponding 95% confidence intervals were -6.5 to 6.0 ml, -3.5 to 6.5 ml, and -7.0 to 4.0 ml, respectively. The resulting effective dose was 0.5 microSv to one leg. CONCLUSION: Computed tomography can be used as a precise quantitative method to measure small volume changes of the lower leg as a whole, and separately for muscle and adipose tissue. The results were obtained with a negligible effective dose, lower than that delivered by modern fan-beam dual-energy X-ray absorptiometry whole-body examinations and equal to a few hours of background radiation.

Tranexamic acid radically decreases blood loss and transfusions associated with total knee arthroplasty.

The application of a pneumatic tourniquet in orthopedic procedures enhances local fibrinolysis. Consequently, a short-term antifibrinolytic therapy may be indicated in this clinical situation to reduce postoperative blood loss. The purpose of this prospective double-blind study was to investigate the effect of tranexamic acid (TA) on blood loss associated with total knee arthroplasty (TKA). Seventy-five patients scheduled for 77 TKAs were randomized to receive either TA (n = 39) or equal volume of normal saline (NS, n = 38). Before deflation of the tourniquet, 15 mg/kg of TA was given intravenously followed by two 10-mg/kg additional doses. Perioperative blood loss gathered in surgical gauzes, suction reservoirs, and postoperative drainage system was measured. The number of transfusions given during hospitalization was registered. Total blood loss (mean +/- SD) was 689 +/- 289 mL in the TA group and 1509 +/- 643 mL in the NS group (P < 0.0001). The mean number of transfused red cell units in the TA group was 1.0 +/- 1.2 compared to 3.1 +/- 1.6 in the NS group (P < 0.0001). Twenty-two patients in the TA group and four patients in the NS group were treated without transfusion (P < 0.00003). Two patients in the TA group and three in the NS group had a deep venous thrombosis, including a fatal case of pulmonary embolism in the NS group. We conclude that short-term TA therapy significantly reduces TKA-associated blood loss and transfusion requirements without increasing thromboembolic complications.

Tranexamic acid (Cyklokapron) reduces perioperative blood loss associated with total knee arthroplasty.

In this prospective, randomized, double-blind study, we have investigated the effect of an antifibrinolytic agent, tranexamic acid (Cyklokapron), on blood loss and transfusion requirements associated with total knee arthroplasty. Twenty-nine patients were allocated randomly to receive either tranexamic acid 15 mg kg-1 or an equal volume of placebo a few minutes before a tourniquet was deflated. Blood loss during surgery, in the recovery room and on the surgical ward was recorded, together with the number of units of blood transfused in hospital. Mean blood loss during surgery was 428 (SD 254) ml in the tranexamic acid group (n = 15) compared with 415 (244) ml in the placebo group (n = 13). In the recovery room the tranexamic acid group lost 127 (95) ml and the placebo group 576 (245) ml (P < 0.001). On the ward the respective volumes were 293 (200) ml and 558 (293) ml (P < 0.01). Total blood loss was 847 (356) ml in the tranexamic acid group and 1549 (574) ml in the placebo group (P < 0.001). During the hospital stay the treatment group received 1.5 (1.3) units of blood compared with 3.3 (1.8) in the control group (P < 0.005). Two patients in the placebo group experienced a thrombotic complication compared with none in the treatment group. We conclude that tranexamic acid reduced perioperative blood loss and transfusion requirements associated with total knee arthroplasty.

Stress symptoms, burnout and suicidal thoughts in Finnish physicians.

Stress symptoms, burnout and suicidal thoughts in Finnish physicians were studied using a questionnaire. The questionnaire, containing 99 questions or groups of questions, was mailed to 3,496 physicians representative, as regards age, sex, specialization and employment, of all active physicians in Finland. Altogether, 2,671 physicians (76%) responded. Stress symptoms in male physicians were similar to those in male managers. In female physicians they were slightly less than in female white-collar workers. In male specialists highest burnout indices were found in general practice and occupational health; psychiatry and child psychiatry; internal medicine, oncology, pulmonary diseases, and dermatology and venereology. In female specialists they occurred in general practice and occupational health; radiology; internal medicine, neurology, pulmonary diseases, and dermatology and venereology. Non-specialists had higher burnout scores than specialists for both sexes. Highest burnout scores in both men and women occurred in those working in municipal health centres. Lowest scores occurred in those working in private practice, universities, research institutes, and public offices and organizations. Suicidal intent tended to be commoner in physicians than in the general population. It was also commoner in female (26%) than in male (22%) physicians. The results indicate a polarization between "higher burnout specialities", often dealing with chronically ill, incurable or dying patients (e.g. specialties such as oncology, pulmonary diseases and psychiatry), on the one hand and "lower burnout specialties", often dealing with curable diseases and favourable prognoses (e.g. specialties such as obstetrics and gynaecology, otorhinolaryngology and ophthalmology), on the other.

Analytical characterization of cytochrome oxidase preparations with regard to metal and phospholipid contents, peptide composition and catalytic activity.

A number of preparations of cytochrome oxidase have been analyzed for metals by energy dispersive X-ray fluorescence spectrometry. The EPR characteristics, the peptide compositions, the protein and phospholipid contents as well as the catalytic constants of the samples have also been determined. It is confirmed that the enzyme functional unit contains three copper atoms and one zinc atom in addition to two iron atoms. On the basis of the parameters determined for the different samples it is suggested that a high catalytic activity of a preparation can be correlated to a number of other analytical characteristics.

Doctors' drinking habits and consumption of alcohol.

Alcohol consumption and drinking habits among Finnish doctors were studied as part of a survey of stress and burnout. A questionnaire containing 99 questions or groups of questions was sent to all 3496 practising doctors aged under 66 randomly selected from the registry of the Finnish Medical Association. Altogether 2671 doctors (76%) responded; this sample was representative of the Finnish medical profession. The average weekly consumption of alcohol during the past year and various aspects of drinking behaviour were assessed, and the presence or absence of symptoms and diseases often encountered among heavy drinkers and addicts was determined. The data were analysed separately for men and women, for those aged less than or equal to 40 and greater than 40, and for the men with high and low alcohol consumption and with high and low scores on the index of drinking habits. Selected variables related to work, stress, and coping were correlated with alcohol consumption and drinking behaviour. The median consumption of alcohol among male doctors was 4876 g (6.2 litres) and among female doctors 2226 g (2.8 litres) of absolute alcohol per person per year and was higher in those aged over 40. Beer was most commonly drunk by men and wine by women. Increased alcohol consumption was associated with older age, disappointment with career, heavy smoking, use of benzodiazepines, stress and burnout symptoms, suicidal thoughts, general dissatisfaction, and diseases related to alcohol. Drinking habits were heavier among doctors working in community health centres, those taking long sick leaves, younger doctors disappointed with their careers or the atmosphere at work, and older doctors immersed in their work. Alcohol consumption among doctors seems to be higher than that of the general population in Finland, and heavy drinking seems to be associated with stress and burnout.

The existence of glutathione and cysteine disulfide-linked to erythrocyte carbonic anhydrase from tiger shark.

In this study it is shown that the higher molecular weight previously reported for tiger shark carbonic anhydrase (carbonate hydro-lyase, EC 4.2.1.1) compared to other carbonic anhydrases is decreased to a normal value around 30 000 after disulfide reduction of the enzyme. This difference in molecular weight is at least partly due to the existence of disulfide-linked glutathione and cysteine residues. Approx. 3 mol glutathione and a similar amount of cysteine are shown to be bound per mol enzyme. The presence of these factors also has effects on the enzyme activity.

Purification, calcium-binding properties, and conformational studies on a 28-kDa cholecalcin-like protein from bovine brain.

A large-scale preparation method for bovine brain 28-kDa cholecalcin-like protein is described. Flow dialysis binding studies revealed that the protein binds at least 3 mol of Ca2+/mol of protein. The protein undergoes conformational changes on binding calcium as shown by UV differential absorption spectroscopy, near and far UV circular dichroism, and intrinsic fluorescence. Circular dichroism (CD) studies in the far UV indicate an apparent increase in helical content in the presence of Ca2+. The effect of calcium on the protein structure is nearly maximum for 1 Ca2+ bound/protein molecule. UV differential absorption studies on the binding of the Ca2+ agonist Tb3+ and Tb3+ luminescence induced by energy Trp----Tb3+ transfer indicate that Tb3+ binds to two higher affinity Ca2+-binding sites. These sites are probably very close to the single Trp residue. Analysis of the fluorescence parameters of the single tryptophan residue in the apoprotein and its accessibility to ionic and neutral quenchers suggests that this residue is located in a highly hydrophobic domain on the protein surface.

Iron-rich particles in European eel (Anguilla anguilla L.).

Magnetic material in the European eel (Anguilla anguilla L.) was investigated by a combination of magnetic susceptibility measurements, energy dispersive X-ray fluorescence analysis and transmission electron microscopy. It was shown that the magnetic material is associated with iron. The main part of the iron is present in the form of iron-rich particles with irregular shapes about 100-3000 A large. The structures of magnetite (Fe3O4), hematite (alpha-Fe2O3) and alpha-iron (bcc structure) were identified. The particles are composed of more than one of these phases with magnetite being a minority phase when present. The iron-rich particles found in the eel are different from the materials reported for bacteria or bees.