Survival of massive allografts in segmental oncological bone defect reconstructions.

Reconstructions of large segmental bone defects after resection of bone tumours with massive structural allografts have a high number of reported complications including fracture, infection and non-union. Our goal is to report the survival and complications of massive allografts in our patients. A total of 32 patients were evaluated for fracture, infection, non-union rate and survival of their massive allograft reconstructions. The average follow-up for this group was five years and three months. The total fracture rate was 13% with a total infection rate of 16%. We found a low union rate of 25%. The total survival of the allografts was 80.8% (+/- 18.7%) after five years. We found a five-year allograft survival of 80.8% which is comparable with other studies.

Treatment of scaphoid non-union with a percutaneous corticocancellous bone graft.

Thirty-three symptomatic scaphoid non-unions were treated by a simple, minimally invasive procedure using a percutaneous autologous corticocancellous bone graft. After an average follow-up of 3.5 years, union was observed in 29 cases. These patients had no, or mild, pain at work and an almost normal range of motion and grip strength. No progression to osteoarthritis was observed.

Patient satisfaction after total knee arthroplasty: a comparison between subjective and objective outcome assessments.

We used a visual analog scale (VAS) to assess the satisfaction after total knee arthroplasty (TKA) in a group of 108 patients (126 TKAs) with short-term to medium-term follow-up. We also used the Knee Society scoring system, Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC), pain VAS, and survival analysis. A comparison between the subjective and objective outcome systems revealed only poor correlations. This comparison suggests that the concerns and priorities of patients and surgeons differ. The outcome assessed with the satisfaction VAS revealed a significantly better subjective outcome in rheumatoid arthritis patients compared with osteoarthritis patients, whereas Knee Society scores were not different. The satisfaction VAS provides additional information about subjective outcome after TKA.

A mild stress due to hypergravity exposure at young age increases longevity in Drosophila melanogaster males.

Drosophila melanogaster flies were exposed to hypergravity starting at two days of age, the range of gravity levels used being 2.58-7.38 g. No longevity change was observed for exposures of less than 14 days. The longevity of males increased if they were submitted to hypergravity for durations ranging from 14 to 24 days. This increase in longevity was never observed in females. The positive effect of exposure to hypergravity has been replicated in two laboratories using two wild-type strains and different rearing conditions. A short hypergravity exposure seems to be a mild stress, yielding positive effects on longevity. This is in accordance with two previous studies showing a slight longevity increase after heat shock in the nematode Caenorhabditis elegans and in Drosophila melanogaster.

Motor dysfunction and reflex sympathetic dystrophy. Bilateral motor denervation in an experimental model.

Reflex sympathetic dystrophy (RSD) is a neuropathic pain condition most often occurring in relation to trauma to, or surgery on, an extremity. It is characterized among other things by motor disturbances such as joint stiffness and tremor. Signs and symptoms can be induced in a rat model through chronic constriction of a sciatic nerve (CCI-model). In this study the CCI-model was used to evaluate the extent of bilateral peripheral motor nerve-fiber involvement in relation to ligature localization. In 12 Lewis rats, the common sciatic nerve was loosely ligated with four chromic catgut ligatures at the midthigh level just proximal to the right sciatic trifurcation. Acetylcholinesterase (CE) histochemistry of sciatic (distal and proximal to ligation) and corresponding contralateral nerve biopsy specimens was performed at 21 days after ligation. An additional 12 rats were sham-operated and served as controls. As compared to sham-operated controls or contralateral nonligated sciatic nerves, CE histochemistry after 21 days revealed a marked decrease of CE-positive fibers in cross-sections taken from distal and proximal sciatic nerve biopsies ipsilateral to the ligatures. In addition, as compared to sham-operated controls, there was a decrease of CE-positive fibers in cross-sections taken from contralateral nonligated sciatic nerves. The present findings indicate profound motor denervation, distal as well as proximal to the ligatures. Motor denervation also affected the contralateral nonligated sciatic nerve. The evident usefulness of the CCI-model for the study of RSD places the present results in line with the concept of central nervous system involvement in the pathophysiology of RSD.

Motor denervation induces altered muscle fibre type densities and atrophy in a rat model of neuropathic pain.

Loose ligation of a sciatic nerve in rats (chronic constriction injury; CCI) provokes sensory, autonomic, and motor disturbances like those observed in humans with partial peripheral nerve injury. So far, it is unknown whether these motor disturbances result from (mechanical) allodynia or from damage to the motor neuron. These considerations prompted us to assess, in CCI rats, the density of motor axons in both the ligated sciatic nerve and the ipsilateral femoral nerve. To this end, we determined the number of cholinesterase positive fibres. It has been demonstrated previously that muscle fibre type density may be used as a measure of motor denervation and/or hypokinesia. Therefore, the myofibrillar ATPase reaction was employed to assess fibre type density in biopsies obtained from the lateral gastrocnemius muscle (innervated by sciatic nerve) and rectus femoris muscle (innervated by femoral nerve). We observed axonal degeneration of motor fibres within the loosely ligated sciatic nerve, both at an intermediate (day 21) and at a late stage (day 90) after nerve injury. The reduction in the number of motor nerve fibres was more pronounced distal to the site of the ligatures than proximal. A (less pronounced) reduction of motor fibres was observed in the ipsilateral (non-ligated) femoral nerve. In line with these findings, we observed altered fibre type densities in muscle tissue innervated by the ligated sciatic nerve as well as the non-ligated femoral nerve indicative of motor denervation rather than hypokinesia. The findings of this study suggest that the motor disorder induced by partial nerve injury involves degeneration of motor nerve fibres not only within the primarily affected nerve but also within adjacent large peripheral nerves. This spread outside the territory of the primarily affected nerve suggests degeneration of motor neurons at the level of the central nervous system.

Neurogenic inflammation in an animal model of neuropathic pain.

Loose ligation of a rat sciatic nerve (chronic constriction injury (CCI) model) provokes signs and symptoms like those observed in reflex sympathetic dystrophy (RSD) patients. Primary afferent nociceptive C-fibers seem to be involved in an afferent orthodromic as well as in an efferent antidromic manner. In this study we hypothesize that consequent to development of antidromic impulses in C-nociceptive afferents, neuropeptides released from peripheral endings of these fibers, increase skin blood flow (SBF), vascular permeability, and tissue accumulation of polymorphonuclear leukocytes (PMNs). Collectively, these phenomena have been referred to as neurogenic inflammation. To investigate the presence of neurogenic inflammation in the CCI-model, we assessed skin blood flow (SBF) as well as the level of edema and accumulation of PMNs in muscle tissue obtained from the affected hindpaw. SBF was measured, by means of laser Doppler flowmetry, before ligation as well as at day 4 after ligation. At day 4, SBF measurements were performed before and after abolition of the capability of C-fibers to mediate a vasodilator response. To this end, capsaicin was applied perineurally. Increased vascular permeability was inferred from the level of edema of muscle tissue as determined by assessment of wet/dry weight ratios of muscle biopsies. PMN accumulation was investigated by enzymatic detection of myeloperoxidase (MPO) activity in muscle biopsies. Compared with preligation values, at day 4 SBF was increased more than twofold (p < 0.05). The latter response was annihilated by capsaicin application. Compared with sham operated controls, wet/dry ratios were higher in the ligated animals (1.104 vs. 1.068; p < 0.05). Likewise, when compared with sham operated controls, MPO activity was found to be increased in the ligated hindpaw (Optic Density 0.15 vs. 0.89; p < 0.001). In conclusion, the findings of this study indicate that loose ligation of a sciatic nerve induces an inflammatory response in the ipsilateral hindpaw, which most likely is mediated by release of neuropeptides from the peripheral endings of antidromically acting nociceptive C-fibres.

Neurogenic inflammation and reflex sympathetic dystrophy (in vivo and in vitro assessment in an experimental model).

In the chronic constriction injury (CCI) model, signs and symptoms similar to those observed in reflex sympathetic dystrophy (RSD) can be induced by loosely ligating a rat sciatic nerve. Skin microcirculatory (inflammation-like) disorders may result from release of vasoactive neuropeptides at peripheral endings of antidromically acting nociceptive nerve fibers. These antidromic mechanisms may account for vasodilation and polymorphonuclear leukocyte (PMN) accumulation in the ligated hindpaw. We assessed skin blood flow (SBF) on the ligated side, by means of laser Doppler flowmetry, before as well as at day 4 after ligation. Postligation SBF measurements were performed before and after selective (capsaicin) conduction blockade of the ligated sciatic nerve. The extent of PMN accumulation was determined by measuring myeloperoxidase (MPO) activity in muscle biopsies obtained from the ligated and contralateral nonligated side. As compared to preligation SBF values, we observed an increase at day 4. SBF returned to preligation values consequent to capsaicin application. MPO activity, when compared to the nonligated side, was higher in biopsies obtained from the ligated side. These findings indicate that in the CCI-model, antidromically acting C-nociceptor nerve fibres increase SBF at 4 days after ligation. In addition, these antidromic mechanisms may induce an inflammatory response in the ipsilateral hindpaw, mediated by release of neuropeptides from the peripheral endings of antidromically acting C-nociceptor nerve fibers. This inflammatory response may account for various signs and symptoms as observed in the CCI model and may mirror pathophysiological mechanisms of RSD.

Life-span of Drosophila melanogaster in highly oxygenated atmospheres.

The life-span of Drosophila melanogaster males kept for their entire life in atmospheres of differing O2 concentration (21%, 30%, 40%) was measured. The life-span decreased linearly with the increase in O2 proportion. In order to test the rate of living and the threshold theories of ageing, Drosophila melanogaster males were kept for 15 days in a given atmosphere and from day 16 on in another one. The life-spans observed in these alternate conditions were very close to the values predicted by the rate of living theory and are thus not compatible with the threshold theory.

Geographic variations of life history strategies in Drosophila melanogaster. I. Analysis of wild-caught populations.

Life history traits--hatchability, developmental time, longevity, and egg production--of five freshly caught European populations of Drosophila melanogaster were measured under homogeneous laboratory conditions. No significant phenotypic correlations between early and late fitness could be found for the five populations at the within-population level. At the between-population level, no consistent indication of any significant genetic correlation, either positive or negative, was detected for the same traits. These results are not in agreement either with the predictions of the antagonistic pleiotropy hypothesis proposed by Williams, nor with the opposite hypothesis suggested by Lints. The results suggest that natural populations of Drosophila melanogaster are genetically different for at least some life history traits measured in the laboratory as soon as possible after capture.

Hypergravity and aging in Drosophila melanogaster: 7. New longevity data.

Longevity of mated and virgin Drosophila melanogaster flies was observed at various gravity levels (1-7.38 g). A slight longevity decrease was observed in the 1-5.14 g range for virgin males, and a larger one in the 5.14-7.38 g range. The effect of gravity was larger for females in the 1-5.14 g range, and at the highest gravity level, both sexes had roughly the same longevity, which however remained high (around 40 days). The longevity of mated flies was lower than that of virgins at 1 g, and only a slight longevity decrease was observed in the 1-7.38 g range in females, this decrease being larger for males. Hypergravity appears to have no dramatic effects on life span and to be of lower importance than the simple effect of mating. This study confirms previous results obtained in the 1-5.02 g range with virgin flies (Le Bourg and Lints, 1989).

Hypergravity, aging and longevity in Drosophila melanogaster.

1. Drosophila melanogaster flies have been used in studies of the effect of hypergravity (HG) on aging and longevity. 2. There is no clear longevity decrease with the gravity level up to 4 g and, even at 7 g, flies still live for roughly 40 days. 3. The HG-related changes in fecundity suggest that flies counteract an increased metabolic demand. 4. Viability is barely affected in HG. 5. These results show that flies remain able to lay viable eggs and to live for a fairly long life, even at high HG levels. 6. The study of three behavioral traits affected by aging (climbing activity, pattern of movement, spontaneous locomotor activity) suggests that flies age faster in HG, while no HG effect is clearly detected at young age. 7. These results are observed at HG levels where longevity is not yet affected. 8. Results are discussed in relation with Pearl's rate of living theory (1928).

Unexplained variations in life span of the Oregon-R strain of Drosophila melanogaster over a four-year period.

The life span of samples of the Oregon-R strain of Drosophila melanogaster was observed, every fourth week, during a four-year period. Large variations, most probably non-random, were observed at both 25 and 21 degrees C. The possible causes of these variations have been searched for, yet no definite conclusion can be reached. The implications of these results for Drosaphila quantitative genetic research are stressed.