Why traumatic leg amputees are at increased risk for cardiovascular diseases.

BACKGROUND: Post-traumatic lower limb amputees have an increased morbidity and mortality from cardiovascular disease. Risk factors for this amplified morbidity and the involved pathophysiologic mechanisms have not been comprehensively studied. METHODS: The MEDLINE database was reviewed, with case-controlled studies and nested in cohort studies eligible for inclusion in this analysis. RESULTS: Insulin resistance, psychological stress and patients' deviant behaviors are prevalent in traumatic lower limb amputees. Each of these factors may have systemic consequences on the arterial system and may contribute to the increased cardiovascular morbidity in traumatic amputees. Abnormalities of arterial flow proximal to the amputation site may hold the explanation for the linkage between the extent of leg amputation and the magnitude of the cardiovascular risk: proximal leg amputation is associated with greater risk than distal amputation and bilateral amputation with greater risk than unilateral amputation. This review focuses on hemodynamic culprits (shear stress, circumferential strain, reflected waves), hemodynamic consequences in proximity to the occluded femoral artery and hemodynamic consequences at a distance. CONCLUSION: Coronary risk in lower limb amputees may be substantially greater than predicted by available algorithms, given that neither hemodynamic nor psychological factors concern the current prediction models. It seems reasonable to take early prophylactic measures in lower limb amputees by discouraging smoking, excessive alcohol consumption and adherence to a low fat diet. Studies are needed to evaluate the optimal intensity of physical exercise effects on reflected pulse waves and their possible long-term consequences. Guidelines for optimal blood pressure, blood glucose and lipid control in amputees need to be convened.

Walking ability following knee arthroplasty: a prospective pilot study of factors affecting the maximal walking distance in 18 patients before and 6 months after total knee arthroplasty.

Functional assessment of patients before and after prosthetic knee arthroplasty is based on clinical examination, which is usually summarized in various knee scores. The present study proposes a different and more subject orientated assessment for functional grading of these patients by measuring their maximal distance of walking ability, which is not apparent from the conventional outcome scores. Eighteen consecutive patients with knee osteoarthritis were evaluated for their knee and knee functional scores (The Knee Society clinical rating system) and for the maximal distance of their walking ability before and 6 months after knee arthroplasty. Specially designed walking ability grading was used for evaluation of walking on walkway. The pre- and post-operative knee scores and maximal walking distance and grading were statistically compared. A significant improvement in the knee and functional scores following surgery was observed. But the maximal walking ability grades and distances did not change significantly following surgery, showing a high relation between pre- and post-operative values. The limitation in post-operative walking was due to the revealed additional health disabilities, not related to the affected knee. Therefore we suggest that pre-operative evaluation of walking abilities should be taken into consideration both for patients' selection and timing of surgery and also for matching of patients' expectation from outcome of prosthetic knee arthroplasty.

Muscle power, locomotor performance and flexibility in aging mentally-retarded adults with and without Down's syndrome.

Longer life expectancy is resulting in increasing numbers of elderly adults with mental retardation (MR). The objective of the study was to compare lower limb isokinetic muscle power, locomotor performance and flexibility of aged adult mentally-retarded individuals with and without Down's syndrome (DS). Nine subjects with MR and DS (mean age 61), and sixteen subjects with MR and without DS (mean age 63), performed leg power testing on a Biodex dynamometer. Parameters measured were dynamic torque, dynamic torque % body weight, and average power % body weight. Functional performance tests including "Timed Get-Up and Go" and flexibility were also analyzed and compared. Results indicate that in knee extension and flexion isokinetic power the MR group without DS showed significantly higher scores than the MR group with DS. The functional performance of elderly adults with MR and DS was significantly impaired compared with MR adults without DS, although no differences were observed between the two groups in the flexibility tests. It was concluded that muscle leg power, and gross motor performance of elderly mentally-retarded individuals without Down's syndrome is better than in those with Down's syndrome.

Structure and function of a second gene cluster encoding the formate dehydrogenase of Wolinella succinogenes.

Wolinella succinogenes contains a single formate dehydrogenase, but two gene loci (fdhI and fdhII) code for the subunits of the enzyme. The nucleotide sequence of fdhII is almost identical with that of fdhI in the region comprising fdhEABCD. The sequences of fdhI and fdhII differ in the promotor regions upstream of fdhE. Deletion mutants lacking either fdhI or fdhII synthesize functional formate dehydrogenases, as shown by growth with formate as electron donor and either fumarate or polysulfide as acceptor substrates, and by the presence of the FdhA subunit and of enzyme activity. In the wild-type strain, the fdhI genes appear to be expressed preferentially during growth with formate and fumarate. The six-times greater amount of the enzyme present upon growth with formate and polysulfide is due to the expression of both fdhI and fdhII. The transcription start sites were located 196-bp and 129-bp upstream of the fdhE start codons of fdhI and fdhII, respectively. An apparently single transcript (5.6 kbp) was detected in polysulfide-grown W. succinogenes by Northern-blot analysis, suggesting that the five open reading frames form operons.

Neurological deficit in a consecutive series of vertebral fracture patients with bony fragments within spinal canal.

The wide spread availability of computerized tomography has added a new dimension to the anatomical evaluation of vertebral fractures. This diagnostic modality has shown that in these fractures, the protrusion of bone spicules into the spinal canal is often encountered. The clinical significance of this finding and its relation to the need of establishing indications for surgery in these patients is controversial. The neurological outcome of patients with postraumatic bony encroachment of the spinal canal is not well documented in the literature, and therefore the adequate therapeutic approach is neither clear nor is it unanimous. Whether treatment should be aggressively surgical with decompression and/or segmental fusion, or conservative, the goal has to be prevention of secondary injury to the spinal cord. This presentation is a mean 4 year follow up study of 38 consecutive patients with spinal fractures and spinal canal narrowing, who were treated conservatively. The results demonstrate that the initial neurological findings have a very significant prognostic value for the neurological outcome, regardless of the spinal segment involved, the type of injury and spinal canal narrowing as demonstrated by computerized tomograms. We conclude that in trauma patients with vertebral fractures and spicules in the spinal canal without evidence of an initial neurological deficit, a favorable neurological prognosis can be predicted, following conservative management.

Upper-limb Postures and Movements during Diamond Polishing.

Previous occupational health studies of diamond polishers have identified high rates of musculoskeletal disorders of the hands and arms in this population, specifically, ulnar neuropathy in the right elbow. These disorders may be due to the repetitive and forceful motions of the upper extremity required to manipulate the hand-held polishing tools. A video-based, biomechanical analysis of the upper extremities of polishers at several diamond-processing factories in Israel was conducted. Detailed motion measurements of the wrists, elbows, and shoulders of polishers were made while the subjects performed their usual work. During a typical workday, the basic polishing cycle, which involves a series of stereotyped hand and arm movements, is repeated more than 5,000 times. Sustained, extreme flexion of the right elbow, which is the arm holding the eyepiece, may account for the higher rates of ulnar neuropathy in this extremity.

The quinone-reactive Ni/Fe-hydrogenase of Wolinella succinogenes.

The hydrogenase (Hyd) isolated from the cytoplasmic membrane of Wolinella succinogenes consists of three polypeptides (HydA, HydB and HydC) and contains cytochrome b (6.4 mumol/g protein), which was reduced upon the addition of H2. The enzyme catalyzed the reduction of 2,3-dimethyl-1,4-naphthoquinone with H2, in contrast to an earlier preparation which was made up of HydA and HydB only and did not contain cytochrome b (Unden, G., Böcher, R., Knecht, J. & Kröger, A. (1982) FEBS Lett. 145, 230-234). This suggests that HydC is a cytochrome b which serves as a mediator in the electron transfer from H2 to the quinone. The hydrogenase genes were cloned, sequenced and identified by sequence comparison with the N-termini of the three subunits. The three genes were arranged in the order hydA, hydB, hydC, with the transcription start site in front of hydA, and were present only once on the genome. Separated by an intergene region of 69 nucleotides, hydC was followed by at least two more open reading frames of unknown function. The amino acid sequences derived from hydA, hydB and hydC were similar to those of the membrane Ni-hydrogenases of seven other bacteria. HydA and HydB also showed similarity to the small and the large subunits of periplasmic Ni-hydrogenases. HydC was predicted to contain four hydrophobic segments which might span the bacterial membrane. Two histidine residues located in hydrophobic segments are conserved in the corresponding sequences of the other membrane hydrogenases and might ligate the haem B.

Ergot poisoning in paraplegia.

Ergot derivatives are widely used for migraine headaches. However, ergotamine tartrate may cause intoxication which may even become fatal. A case of ergot poisoning in a paraplegic patient is reported, where deep vein thrombosis and ischaemia of the lower limbs were the presenting signs.