Reproduction,blood and plasma parameters and gill histology of vendace (Coregonus albula L.) in long-term exposure to acidity and aluminum

Vendace were exposed to pHs 4.75 and 5.25 with or without added aluminum (200 microg=7.4 micromol AlL(-1)) from late endogenous vitellogenesis in July through the spawning period. At the normal time of spawning, when 48% of the control females had already released their eggs, 50% of females at pH 4.75+Al had completely unovulated oocytes. The final proportions of completely ovulated females were 14%, 36%, 25%, 61%, and 81% at pH 4.75+Al, pH 4.75, pH 5.25+Al, pH 5.25, and in the control group, respectively. Delayed testes regression was seen in males at pH 4.75+Al. A clear decrease in plasma Na(+) and Cl(-) and an increase in blood glucose concentration was detected only near spawning time, from October to November, coincident with Al accumulation inside the gill tissue. It is concluded that seasonal changes, probably related to reproductive physiology or to the decrease in water temperature, are associated with the increase in Al toxicity in vendace.     

Bioabsorbable miniplating versus metallic fixation for metacarpal fractures

Bioabsorbable implants offer an attractive alternative to metallic implants to stabilize small bone fractures in the hand. Self-reinforced bioabsorbable miniplating for metacarpal fractures was studied in bones from cadavers and compared with standard metallic fixation methods. One hundred twelve fresh-frozen metacarpals from humans had three-point bending and torsional loading after transverse osteotomy followed by fixation using seven methods: (1) dorsal and (2) dorsolateral 2-mm self-reinforced polylactide-polyglycolide 80/20 plating, (3) dorsal and (4) dorsolateral 2-mm self-reinforced poly-L/DL-lactide 70/30 plating, (5) dorsal 1.7-mm titanium plating, (6) dorsal 2.3-mm titanium plating, and (7) crossed 1.25-mm Kirschner wires. In apex dorsal and palmar bending, dorsal self-reinforced polylactide-polyglycolide and poly-L/DL-lactide plates provided stability comparable with dorsal titanium 1.7-mm plating. When the bioabsorbable plates were applied dorsolaterally, apex palmar rigidity was increased and apex dorsal rigidity was decreased. Bioabsorbable platings resulted in higher torsional rigidity than 1.7-mm titanium plating and in failure torque comparable with 2.3-mm titanium plating. Low-profile selfreinforced polylactide-polyglycolide and poly-L/DL-lactide miniplates provide satisfactory biomechanical stability for metacarpal fixation. These findings suggest that bioabsorbable miniplating can be used safely in the clinical stabilization of metacarpal and phalangeal fractures.     

Occurrence of chronic disease in former top-level athletes. Predominance of benefits,risks or selection effects?

Former elite athletes from most sports disciplines have lower overall morbidity risk and enjoy better self-rated health in later years compared with the general population and matched controls who were healthy at young age. This is seen particularly among former endurance athletes who have a lower incidence of coronary heart disease and type 2 diabetes mellitus. Most often data are available only for men. Based on the available data, participation in elite sports cannot be regarded as an overall health hazard. However, aside from a high risk of acute injury in specific sports, possible negative effects of long-standing athletic activity on the development of osteoarthritis should not be neglected. It should also be remembered that elite athletes are a biologically and genetically select group who are not representative of the population at large. Given the nature of the available data, the possible health consequences of recent changes in different characteristics of sports, such as training practices, professionalism and use of doping, cannot be properly predicted.     

Sports career-related musculoskeletal injuries: long-term health effects on former athletes

Despite the high absolute number of sports injuries, most are not usually severe and consequent permanent disabilities are uncommon. Based on epidemiological data, former athletes have more degenerative changes in their joints and spine compared with control populations; however, at old age, their good muscle function related to high physical activity level seems to compensate for the effects of degenerative changes on function. There are former athletes who report disabilities due to different types of musculoskeletal injuries from sports careers. This article attempts to characterise this problem; however, more detailed studies are needed, particularly because the training regimens of the athletes seem to be increasingly demanding.     

Alternative materials to improve total hip replacement tribology

An improvement in tribology of bearing surfaces is an effective means of increasing the longevity of total hip replacement (THR). Currently, 3 approaches are available to achieve this aim: first, use of highly cross-linked UHMWPE; second, aluminum oxide ceramic bearings, and third, metal-on-metal bearings. Cross-linking reduces the wear resistance of UHMWPE markedly without impairment of other significant properties of the material. Simulator studies and some clinical long-term (10-22 years) follow-up surveys suggest an almost immeasurable wear of the highly cross-linked UHMWPE-based acetabular components during an expected clinical life span. Bioinert alumina ceramic (aluminum oxide) was introduced 3 decades ago for THR-bearing surfaces to improve performance and longevity. Alumina ceramic is entirely biostable and bioinert and has good mechanical properties. For correctly positioned alumina-on-alumina bearings, the annual linear wear rate has been reported to be 3.9 microm. Alumina heads have been successfully used in combination with polyethylene sockets, but as regards wear, the best results have been obtained with alumina-on-alumina bearings. In ceramic THR bearings, precise manufacture and contact surface geometry, including optimal clearance, are most important. For the currently available products, the component fracture risk is almost nonexistent (less than 1 per 1000). Metal-on-metal bearings were used in the early stage of THR surgery, although not all old designs were successful. More recent analyses of the early series have shown the advantages of metal-on-metal to be better and have led to a renaissance of this articulation. Initially, stainless steel was used because it was easy to manufacture and polish. Current metal-on-metal bearings are based on cobalt-chromium-molybdenum alloys with varying carbon contents. Such bearings are self-polishing. Linear wear rates remain at the level of a few microm a year. An improvement in technology has increased the life span of the above three THR-bearing systems. Although the technical solutions differ considerably, they all seem to improve clearly the tribology and longevity of the THR. Each of these bearing concepts will probably permit the use of larger head sizes, to reduce the risk of impingement and luxations.     

Modulation of electroencephalographic responses to transcranial magnetic stimulation: evidence for changes in cortical excitability related to movement

Transcranial magnetic stimulation (TMS) and multichannel electroencephalography (EEG) were used for the investigation of cortical excitability preceding voluntary movement in human subjects. The study showed the practical value of the combined TMS-EEG approach in differentiating between cortical and spinal-cord mechanisms, which is difficult with conventional electromyographic measures alone. TMS induced a pronounced negativity (N100) lasting for 150-200 ms, with the amplitude maximum in the stimulated hemisphere. When TMS was applied just before the onset of the visually triggered movement, N100 was markedly attenuated, although motor evoked potentials (MEPs) became larger. We suggest that the N100 component represents an inhibitory response following TMS. This interpretation is in agreement with intracellular recordings in animals, paired-pulse TMS studies and experiments showing increased premovement excitability on the basis of MEPs. N100 was not affected only by the subsequent movement, but also by the switching from rest to the motor-task condition, which caused a slight attenuation of the N100 component; no changes, however, were found in the amplitude of MEPs, suggesting that modified excitability did not affect the output of the corticospinal pyramidal cells. By contrast to MEPs, N100 was modulated also by the presentation of the visual stimulus alone, i.e. when no movement was required. This attenuation suggests that even in a rest condition visual stimuli have an access to the sensorimotor regions of the cortex, most probably through ascending arousal brain systems.     

n-3 Fatty acids and 5-y risks of death and cardiovascular disease events in patients with coronary artery disease

BACKGROUND: Data on the association of n-3 fatty acid content in serum lipids with mortality in patients with coronary artery disease (CAD) are limited. OBJECTIVE: We hypothesized that a high proportion of n-3 fatty acids in serum lipids would be associated with reduced risks of death and coronary events in patients with established CAD. DESIGN: We measured dietary intakes via food records and the fatty acid composition of serum cholesteryl esters (CEs) in 285 men and 130 women with CAD (x age: 61 y; range: 33-74 y). The patients participating in the EUROASPIRE (European Action on Secondary Prevention through Intervention to Reduce Events) study were followed up for 5 y. RESULTS: During the follow-up, 36 patients died, 21 had myocardial infarctions, and 12 had strokes. The relative risks (RRs) of death adjusted for cardiovascular disease risk factors for subjects in the highest tertile of fatty acids in CEs compared with those in the lowest tertile were 0.33 (95% CI: 0.11, 0.96) for alpha-linolenic acid, 0.33 (0.12, 0.93) for eicosapentaenoic acid, and 0.31 (0.11, 0.87) for docosahexaenoic acid (P for trend = 0.063, 0.056, and 0.026, respectively). A high proportion of eicosapentaenoic acid in CEs was associated with a low risk of CAD death. Compared with no consumption, consumption of fish tended to be associated with a lower risk of death [1-57 g/d, RR = 0.50 (0.20, 1.28); > 57 g/d, RR = 0.37 (0.14, 1.00); P for trend = 0.059]. CONCLUSION: High proportions of n-3 fatty acids in serum lipids are associated with a substantially reduced risk of death.     

Intron 4 polymorphism of the endothelial nitric oxide synthase gene is associated with elevated blood pressure in type 2 diabetic patients with coronary heart disease

The endothelial nitric oxide synthase (eNOS) gene is responsible for constitutive nitric oxide synthesis and arterial vasodilatation. Recently two polymorphisms, the 27-bp repeat sequence in intron 4 and the Glu298Asp substitution in exon 7 of the eNOS gene have been reported to be related to coronary heart disease (CHD). We screened these polymorphisms of the eNOS gene in 308 unrelated nondiabetic subjects with CHD, in 251 unrelated patients with type 2 diabetes with CHD, and in 110 randomly selected healthy subjects without CHD. The 4a and Asp298 allele frequencies of the eNOS gene were 0.19 and 0.36 in nondiabetic patients with CHD, 0.21 and 0.27 in type 2 diabetic patients with CHD, and 0.16 and 0.31 in nondiabetic subjects without CHD (n.s. between the groups). The Asp298 allele in exon 7 of the eNOS gene was not associated with elevated blood pressure in any of the study groups. Among type 2 diabetic patients with CHD the 4a allele in intron 4 of the eNOS gene was associated with elevated levels of systolic (P=0.035) and mean arterial blood pressure (P=0.040). In nondiabetic subjects these associations were not statistically significant. When all study groups were pooled in statistical analysis the 4a allele of the eNOS gene was associated with elevated diastolic (P=0.032) and mean (P=0.030) arterial blood pressure even after adjustment for confounding factors. We conclude that the 4a allele of the eNOS gene is not associated with CHD or type 2 diabetes, but that it is related to elevated blood pressure levels particularly among type 2 diabetic patients with CHD.     

Reactive microglia in aging and dementia: an immunohistochemical study of postmortem human brain tissue

Significantly increased up-regulation of HLA DR (major histocompatibility complex class II antigen) was seen using immunohistochemistry in postmortem brain tissue from demented patients with Alzheimer’s disease (AD) (73 cases, 61 females/12 males, mean age 84 ± 9 years) compared to controls (22 cases, 10 females/12 males, mean age 78 ± 9 years). The counts of HLA DR-expressing activated microglia were significantly higher in female AD patients compared to males, significantly higher in AD patients with the age at death greater than 75 years compared to those dying younger and higher, although not statistically significantly, in AD patients with the apolipoprotein E (ApoE) ɛ4 allele compared to those patients not carrying this allele. In contrast to the situation in AD patients, in the control cases the HLA DR expression was higher in males compared to females. Furthermore, in the very old non-demented patients (age at death > 80 years), a decrease in the up-regulation of HLA DR expression was observed. A significant correlation between activated microglia and neurofibrillary tangles was seen in female AD patients compared to males, in AD cases without ApoE ɛ4 allele compared to those with this allele, in sporadic cases compared to familial and in cases with senile rather than presenile onset of the disease. Our results indicate that there is an age- and/or sex-related variability in up-regulation of HLA DR expression of microglia and that the linkage between this up-regulation and AD lesions is significantly influenced by the ApoE ɛ4 allele, gender of subjects, age at onset and familiality of the disease. Received: 20 May 1998 / Revised: 5 August 1998, 4 October 1998 / Accepted: 21 October 1998     

Internal fixation of forearm fractures in children

Fourteen children with severely displaced diaphyseal fractures of both bones of the forearm treated with open reduction and internal fixation were reviewed; these operations represented 9 per cent of all the diaphyseal forearm fractures in children during a 9-year period. The mean age of the patients at the time of the injury was 12 (7-14) years; they were reexamined 8 (5-11) years later, all after cessation of growth.

At follow-up, limited prosupination, observed in 8 patients, was associated with a fracture of the proximal third of the forearm; limited motion of the radiocarpal joint, in 2 patients, was associated with shortening of the ulna. Only 4 patients complained of pain or were aware of restricted motion, and the average function was good.

Open reduction and internal fixation is indicated in displaced fractures of the forearm even in children.