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Osseous overgrowth after post-traumatic amputation of the lower extremity in childhood.

Severe accidents in children may cause extreme destruction of the lower extremities. In some cases, there is no possibility to preserve the limbs. Initially, a weight-bearing stump cannot be achieved after amputation due to unstable local and soft tissue conditions. This critical situation is often complicated by one of the leading problems in the limb-deficient child - the development of osseous overgrowth. Bizarre overgrowth of the stump may lead to skin perforation, pressure ulcers, and difficulties with the prosthesis. Since 1993, we have been able to follow five pediatric and adolescent patients (2 years to 17 years old) with six post-traumatic amputations of the lower extremities. Four of these cases developed osseous overgrowth. One child treated with initial autologous stump-capping had excellent soft tissue conditions and no problems with the artificial limb. We also report on a case of bizarre and extensive new bone formation. We conclude that close follow-up visits after post-traumatic amputations in children are essential because of new bone formation which may endanger the soft tissue situation of the stump. Unfortunately, surgical revisions have to be performed quite often. To avoid several surgical corrections, an initial stump-capping with autologous material from the injured limb can be performed. Thus, the number of secondary procedures may be reduced drastically.

Adolescent↗

Extreme human breath-hold diving.

In this paper, the respiratory, circulatory and metabolic adjustments to human extreme breath-hold diving are reviewed. A survey of the literature reveals that in extreme divers, adaptive mechanisms take place that allow prolongation of apnoea beyond the limits attained by non-diving subjects, and preservation of oxygen stores during the dives. The occurrence of a diving response, including peripheral vasoconstriction, increased arterial blood pressure, bradycardia and lowered cardiac output, is strongly implicated. Some peripheral regions may be excluded from perfusion, with consequent reliance on anaerobic metabolism. In addition, extreme breath-hold divers show a blunted ventilatory response to carbon dioxide breathing, possibly as a consequence of frequent exposure to high carbon dioxide partial pressures during the dives. These mechanisms allow the attainment of particularly low alveolar oxygen (< 30 mmHg) and high alveolar carbon dioxide (> 50 mmHg) partial pressures at the end of maximal dry breath-holds, and reduce oxygen consumption during the dive at the expense of increased anaerobic glycolysis (rate of blood lactate accumulation > 0.04 mM.s-1). The current absolute world record for depth in breath-hold diving is 150 m. Its further improvement depends upon how far the equilibrium between starting oxygen stores, the overall rate of energy expenditure, the fraction of energy provided by anaerobic metabolism and the diving speed can be pushed, with consciousness upon emersion. The ultimate limit to breath-hold diving records may indeed be imposed by an energetic constraint.

Adaptation, Physiological↗

Extreme isotopic depletion of nitrogen in New Zealand lithophytes and epiphytes; the result of diffusive uptake of atmospheric ammonia?

Several lichens and the terrestrial alga Trentepohlia were found to have extremely depleted 15N signatures at two sites near the Rotorua geothermal area, New Zealand. Values, typically -20 per thousand, with several extreme cases of -24 per thousand, are more isotopically depleted than any previously quoted delta15N signature for vegetation growing in natural environments. For Trentepohlia, distance from a geothermal source did not affect isotopic signature. A 100-km transect showed that the phenomenon is widespread and the discrimination is not related to substrate N, or to elevation. Rainfall NHx and atmospheric gaseous NH3 (NH3(g)) were shown to be isotopically depleted in the range -1 per thousand to -8 per thousand and could not, of themselves, be responsible for the plant values obtained. A simulation of Trentepohlia thallus was created using an acidified fiberglass mat and was allowed to absorb NH3(g) from the atmosphere. Mats exposed at the geothermal sites and on farm-land showed a significant further depletion of 15N to -17 per thousand. We hypothesize that the extreme isotopic depletion is due to dual fractionation: firstly by the volatilization of NH3(g) from aqueous sources into the atmosphere; secondly by the diffusive assimilation of that NH3(g) into vegetation. We further hypothesize that lithophytes, epiphytes, and higher plants, growing on strongly N-limited substrates, will show this phenomenon more or less, depending on the proportion of diffusively assimilated NH3(g) utilized as a N source. Many of the isotopically depleted delta15N signatures in vegetation, previously reported in the literature, especially epiphytes, may be due to this form of uptake depending on the concentration of atmospheric NH3(g), and the degree of reliance on that form of N.

Air Pollutants↗

The effect of energy restriction, walking, and exercise on lower extremity lean body mass in obese women with osteoarthritis of the knee.

Two hundred and twenty-eight Japanese women, aged 45-69 years, with osteoarthritis of the knee (knee OA) and a body mass index of greater than 26.4 self-selected one of the following interventions: (1) a nonsteroidal anti-inflammatory drug (NSAID) alone (NA group; n = 52), (2) the NSAID with nonweight-bearing exercises (NE; n = 49), (3) the NSAID combined with walking (NW; n = 35), (4) an energy restriction diet plus the NSAID (ND; n = 29), (5) the diet combined with the NSAID and strengthening exercises (NDE; n = 37), or (6) the diet combined with the NSAID and walking (NDW; n = 26). Body weight and lower extremity lean body mass (L-LBM), assessed with segmental bioelectrical impedance, were measured at the outset and at 8 weeks in the six therapy groups. Interval changes in L-LBM and L-LBM per body weight (L-LBM/weight) were compared among the six groups at the conclusion. The Lequesne index can index of severity of osteoarthritis of the knee at the final assessment, compared with that at the initial assessment, was significantly decreased in the NE group, but not in the NW or the NA groups (P = 0.023). There was a significant increase in the L-LBM/weight in the NE group, but not in the NA or NW groups (P = 0.002 between NE and NA; P = 0.019 between NE and NW). There was a significant reduction in the Lequesne index in the NDE group in comparison with the ND and NDW groups (P = 0.0001 between NDE and ND; P = 0.0001 between NDE and NDW). There was a significant increase in L-LBM/weight in the NDE group, but not in the NDW or the ND groups (P = 0.011). Adjunctive therapy with nonweight-bearing lower extremity exercises appears to be more efficacious for prevention of lower extremity loss of muscle mass than adjunctive therapy with walking for obese women with knee OA.

Aged↗

Intracellular ion and organic solute concentrations of the extremely halophilic bacterium Salinibacter ruber.

Salinibacter ruber is a red obligatory aerobic chemoorganotrophic extremely halophilic Bacterium, related to the order Cytophagales. It was isolated from saltern crystallizer ponds, and requires at least 150 g l(-1) salt for growth. The cells have an extremely high potassium content, the ratio K(+)/protein being in the same range as in halophilic Archaea of the order Halobacteriales. X-ray microanalysis in the electron microscope of cells grown in medium of 250 g l(-1) salt confirmed the high intracellular K(+)concentrations, and showed intracellular chloride to be about as high as the cation concentrations within the cells. A search for intracellular organic osmotic solutes, using (13)C-NMR and HPLC techniques, showed glutamate, glycine betaine, and N-alpha-acetyllysine to be present in low concentrations only, contributing very little to the overall osmotic balance. The results presented suggest that the extremely halophilic Bacterium Salinibacteruses a similar mode of haloadaptation to that of the Archaea of the order Halobacteriales, and does not accumulate organic osmotic solutes such as are used by all other known halophilic and halotolerant aerobic Bacteria.

Bacteroidetes↗

Rare cause of acute ischemia of the right upper extremity: thrombosis of a retroesophageal subclavian artery.

Thrombosis of a subclavian artery is an uncommon cause of acute upper extremity ischemia in the elderly. Malformations of the aortic arch system are also rare. The purpose of this report is to describe an unusual case involving acute ischemia of the right upper extremity due to extensive thrombosis of a retroesophageal right subclavian artery (RSA) in a 79-year-old woman. Despite delayed diagnosis of the underlying etiology, the patient was successfully treated by extensive thrombectomy of the arteries in the upper extremity and right subclavian-to-carotid artery transposition.

Acute Disease↗

Major lower extremity amputation in an academic vascular center.

Major lower extremity amputations continue to be performed despite an aggressive policy of revascularization. Factors leading to amputation were analyzed to determine whether a reduction in the limb loss rate is possible. A retrospective analysis of a prospectively maintained vascular registry was performed to identify patients undergoing above-knee amputation (AKA), below-knee amputation (BKA), and lower extremity revascularization (LER) for limb salvage between January 1, 1999 and January 1, 2002. Patient demographics, comorbidities, insurance carriers, and indications for operative intervention were analyzed. Greater than one-half of all major lower extremity amputations are performed in patients who have failed attempts at revascularization or who are not candidates for LER due to anatomic factors. However, one-quarter of eventual amputees present very late to the vascular surgeon with extensive gangrene or infection that precludes limb salvage. Prompt patient referral and treatment may improve outcome in this group of patients. In our study, insurance issues did not appear to affect treatment. Renal failure continues to play a major role in limb loss.

Academic Medical Centers↗

Methicillin-resistant Staphylococcus aureus infection does not adversely affect clinical outcome of lower extremity amputations.

Methicillin-resistant Staphylococcus aureus was first identified in isolation in Europe during the 1960's. Now widespread throughout the world, infection with this organism has emerged as a major problem in surgical practice. However, it remains debatable whether MRSA is more virulent than methicillin-susceptible strains. We have reviewed our most recent 4-year experience of lower extremity amputations to examine the influence of MRSA and non-MRSA infection on clinical outcome. During the past 4 years, 165 patients underwent lower extremity amputation for SVS/ISCVS category III acute limb ischemia and grades II and III chronic limb ischemia. Forty-five had documented MRSA infection, while 57 patients had documented infection with other flora. All patients were treated with appropriate sensitivity-specific antibiotics and aggressive wound care. No significant differences were noted in the level of primary amputation required by the two groups. Similarly, no significant differences were noted in either number of revisions or revision to higher-level amputation, time to heal, hospital length of stay, or 30-day morbidity and mortality rates. Our results demonstrate that MRSA infection does not adversely affect clinical outcome in patients undergoing lower extremity amputations. Appropriate treatment of infections with sensitivity-specific antibiotics, thorough wound debridement, and aggressive wound monitoring should be routine in all patients, regardless of bacterial flora.

Aged↗

Carotid atherosclerosis in patients operated for lower extremity ischemia before the age of 50: a case control study.

The purpose of this study was to investigate the presence of, and to identify factors associated with carotid atherosclerosis in patients, previously operated on for lower extremity ischemia before the age of 50. Forty-eight patients were compared to sex- and age-matched controls. All subjects were examined with duplex ultrasonography of the neck arteries and analysis of serum lipoproteins. History including smoking habits, family history of cardiovascular disease, and medication was also obtained. The patients were examined clinically and their preoperative angiograms were reevaluated. Thirty-one patients (64%) and 13 controls (23%) had a carotid lesion (p < 0.0001). Patients with suprainguinal or multilevel disease had a higher proportion of carotid lesions than those with only infrainguinal disease in whom the proportion was similar to the controls. A multiple regression analysis among the patients revealed that age, level of lower extremity arterial disease, presence of family history, and the ratio apolipoproteinB/apolipoproteinA discriminated significantly between those with and without carotid disease. It is concluded that a high proportion of patients operated on for lower extremity suprainguinal arterial occlusive disease at an early age have carotid lesions at follow-up, while patients operated on due to isolated infrainguinal disease have a prevalence similar to controls.

Arteriosclerosis↗

Cardiac morbidity and operative mortality following lower-extremity amputation: the significance of multiple Eagle criteria.

The ability of the Eagle criteria (age >70 years, angina, diabetes, Q wave on EKG, history of congestive heart failure) to predict adverse cardiac events following major vascular surgery has previously been demonstrated. However, the utility of these criteria for lower-extremity amputation is not well established. To determine the value of the Eagle criteria for predicting cardiac morbidity and operative mortality following major lower-extremity amputation, we reviewed 214 consecutive procedures performed at two institutions over a 3-year period. Mean age was 62.7 years and 85% of the patients were male. Diabetes was the most frequent Eagle criterion (74%). The mean number of Eagle criteria was 1.6. Fifty-six percent of the amputations were below the knee, 24% were above the knee, and 20% were guillotine. On multivariate regression analysis, the presence of two or more Eagle criteria (16% vs. 4%, p = 0.04) and decompensated heart failure (39% vs. 7%, p = 0.003) were predictive of adverse cardiac events. The only predictor of postoperative mortality was the presence of two or more Eagle criteria (15% vs. 4%, p = 0.004). Our evaluation of the results of this study led us to conclude that patients requiring major lower-extremity amputation for major vascular disease who have multiple Eagle criteria or decompensated congestive heart failure are at high risk for adverse cardiac events and postoperative death. These findings should be used to guide perioperative cardiac evaluation and therapy.

Aged↗

Can a tissue-engineered skin graft improve healing of lower extremity foot wounds after revascularization?

A bilayered tissue-engineered skin graft composed of human neonatal foreskin fibroblasts and keratinocytes in a type I bovine collagen matrix has been developed. We sought to determine if this graft improves wound healing after lower extremity revascularization. Thirty-one previously ischemic foot wounds were randomly assigned to moist dressing changes or tissue-engineered skin graft within 60 days of revascularization. In the grafted group, 10 received meshed and 11 received unmeshed graft. Wound healing was followed by wound area measurements and photography. There were no statistically significant differences between groups in patient age, sex, diabetes or renal failure risk factors, revascularization procedure, or wound location or size. Treatment with tissue-engineered skin graft was significantly more effective than moist dressing in the percentage of wounds healed (62 vs. 0% at 8 weeks, 86 vs. 40% at 12 weeks, p < 0.01) and the median time to complete wound closure (7 vs. 15 weeks, p = 0.0021, rank-sum test). There was no difference in the wound closure rate of meshed and unmeshed graft at 4, 8, 12, or 24 weeks (p > 0.05). Three indolent localized wound infections in the tissue-engineered skin graft group were the only complication. Tissue-engineered skin grafting can be used safely in previously ischemic wounds after lower extremity revascularization. Treatment with this graft promotes healing more rapidly and in more patients than standard moist dressings. It obviates the risk, inconvenience, and expense of donor skin harvesting, anesthesia, and hospitalization associated with autologous skin grafting. This graft may represent an advance in the treatment of previously ischemic lower extremity foot wounds.

Aged↗

Bacterial exopolysaccharides from extreme marine environments with special consideration of the southern ocean, sea ice, and deep-sea hydrothermal vents: a review.

Exopolysaccharides (EPSs) are high molecular weight carbohydrate polymers that make up a substantial component of the extracellular polymers surrounding most microbial cells in the marine environment. EPSs constitute a large fraction of the reduced carbon reservoir in the ocean and enhance the survival of marine bacteria by influencing the physicochemical environment around the bacterial cell. Microbial EPSs are abundant in the Antarctic marine environment, for example, in sea ice and ocean particles, where they may assist microbial communities to endure extremes of temperature, salinity, and nutrient availability. The microbial biodiversity of Antarctic ecosystems is relatively unexplored. Deep-sea hydrothermal vent environments are characterized by high pressure, extreme temperature, and heavy metals. The commercial value of microbial EPSs from these habitats has been established recently. Extreme environments offer novel microbial biodiversity that produces varied and promising EPSs. The biotechnological potential of these biopolymers from hydrothermal vent environments as well as from Antarctic marine ecosystems remains largely untapped.

Antarctic Regions↗

Soft tissue calcifications in the lower extremities of severely diabetic patients simulating venous stasis or collagen vascular disease.

The purpose of this work is to report soft tissue calcifications in severely diabetic patients that simulate venous stasis or scleroderma, without other stigmata of these diseases. Findings from lower extremity radiographs were reviewed on two patients with severe diabetes mellitus and abnormal soft tissue calcifications. Findings were correlated with clinical history, physical exam findings, and laboratory values. Both patients in this study demonstrate radiographic findings of lower extremity soft tissue calcifications similar to those seen in venous stasis or scleroderma. Clinical history, physical examination, and laboratory values support severe diabetes mellitus, with no evidence of these other disease entities. Patients with severe diabetes mellitus may exhibit soft tissue calcifications of their lower extremities that may simulate the changes of venous stasis or scleroderma. This association has not been previously described.

Adult↗

Multidetector-row CT angiography of upper- and lower-extremity peripheral arteries.

With the introduction of multidetector-row CT (MDCT) technology indications for MDCT angiography have expanded to include assessment of the peripheral arteries of the upper and lower extremities. Combined with patient- and scanner-adjusted CT data acquisition and contrast medium application strategies, an accurate and reliable evaluation of the peripheral arteries of the upper and lower extremities is possible. MDCT angiography is cost-effective and accurate for detection of arterial stenosis and occlusion in patients with peripheral arterial disease (PAD). MDCT angiography allows postoperative assessment of peripheral arterial bypass grafts, including bypass graft stenosis and occlusion, as well as presence of aneurysms or arteriovenous fistulas. In addition, MDCT angiography is helpful in particular for visualization of arterial bypass grafts with a complicated extra-anatomical course. Furthermore, pre-operative peripheral vascular mapping can be performed by using MDCT angiography. Finally, due to the integration of MDCT scanners in many trauma centres, MDCT angiography is increasingly being used for assessment of traumatic arterial injuries. This article gives an overview of technical aspects of peripheral MDCT angiography, including scanning parameters, contrast medium application, image postprocessing and radiation exposure, and summarizes the most frequent acute and non-acute indications of MDCT angiography for assessment of the upper- and lower-extremity peripheral arteries.

Angiography↗

Extreme nitrogen oxide and ozone concentrations in Athens atmosphere in relation to meteorological conditions.

In the present study, we investigate the variation of NOx)(NO + NO2) and O3 concentrations and the relation between the extreme events (episodes) of NOx and O3 concentrations and the relevant meteorological conditions in the urban atmosphere of the Athens basin. Hourly data of NO, NO2 and O3 concentrations from 10 representative monitoring sites located in the Athens basin were used, covering the 10-year time period from 1994 to 2003. The results of our analysis show that the concentrations of air pollutants differ significantly from one monitoring site to another, due to the location and proximity of each station to the emission sources. For each site, there are also significant differences in NOx and O3 concentrations from day to day, as well as from month to month and/or from season to season. The annual and seasonal variations show higher NO values in winter and lower in summer. On the contrary, NO2 and O3 values are higher in summer (photochemical production of O3) and lower in winter. These differences are attributed, to a large extent, to the prevailing synoptic and meteorological conditions, the most important between them being the wind direction and speed as well as the atmospheric pressure. Our analysis of the identified 179 extreme NOx air pollution events shows that most of them took place under anticyclonic conditions, associated with calm or weak winds (speed <2.5 ms(-1)) of mostly southern to southwestern directions, as well as with low air temperatures and intense stable surface atmospheric conditions. There exists a significant decreasing tendency in NOx air pollution episodic events over the 10-year study period, resulting in very few to none events in the period from 2000 to 2003. As far as it concerns the extreme O3 concentrations, 34 air pollution events were identified, occurring under high air temperatures, variable weak winds and intense solar irradiation. The trends of O3 concentrations are stronger in suburban sites than in urban ones.

Air Pollutants↗

Lower extremity fractures in motor vehicle collisions: the role of driver gender and height.

In a previous study it was noted that there was a higher incidence of lower-extremity fractures among women drivers. Analyses were based on a linkage between trauma registry and police crash report data. The present study addresses the issue of whether the differences noted are attributed to driver gender or are merely a reflection of differences in driver height. An inverse association was noted between driver height and the incidence of lower-extremity fractures. Those shorter than average (5'7") for this population had a 64% increase in lower-extremity fracture, which can be mainly attributed to ankle/tarsal injuries. Thus, the incidence of these injuries appears to be a function of driver height, with an increase among shorter drivers, most of whom are women.

Accidents, Traffic↗

Mechanism of acute lower extremity pain syndrome in fluoride-treated osteoporotic patients.

Acute pain in the lower extremity, which has previously been attributed to synovitis or fasciitis, develops in about 15 percent of osteoporotic patients treated with sodium fluoride. This report describes 11 osteoporotic women in whom this syndrome developed while they were being treated with sodium fluoride (mean dose 78 mg per day; range, 60 to 90). [99mTc]Hydroxymethylene diphosphonate scintiscanning showed an increased number of foci of abnormal uptake in the lower extremities (p less than 0.05), when compared with results of scintiscanning in 12 nonsymptomatic osteoporotic women treated with sodium fluoride and 12 osteoporotic women treated with oral calcium carbonate only. The increased uptake was not restricted to the areas of pain. Roentgenography revealed stress microfractures in five of the 11 symptomatic patients. It is concluded that the acute lower extremity pain syndrome during fluoride therapy usually results from intense regional bone remodeling, which may be complicated by stress microfractures.

Aged↗

Shotgun arterial injuries of the extremities.

Even though shotgun injuries are often grouped with gunshot wounds, the former are ballistically and clinically far different from gunshot wounds. Two groups of patients with shotgun and gunshot wounds of the extremities, respectively, were compared with regard to clinical features. Although the vascular wound was the most dramatic aspect in both groups of patients, associated injuries, especially to the nerves and bones, played a significant role in the ultimate rehabilitation of the patients with shotgun wounds. Shotgun injuries more frequently required the use of saphenous vein grafts than did gunshot wounds. The infection and amputation rates were much higher in patients with shotgun wounds than in those with gunshot wounds. Patients with shotgun injuries of the extremities often required secondary reconstructive procedures such as tendon transfer or bone and joint fusion. Despite these measures the outlook for the ultimate rehabilitation of the extremity after shotgun injury was dismal, whereas after gunshot wounds complete rehabilitation was the rule.

Amputation, Surgical↗