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Use of lower extremity deep veins as arterial substitutes: functional status of the donor leg.

Large veins (superior and inferior vena cava, portal vein) have been replaced successfully with lower extremity deep veins (superficial femoral-popliteal). Femoropopliteal bypass with superficial femoral-popliteal veins has been reported to give excellent long-term results. Nevertheless, this source of autogenous veins has not gained acceptance, in part because of the fear that deep vein removal will result in severe venous outflow restriction in the donor limb. To assess the clinical and functional effect of excising a deep vein, we compared a group of limbs in which the superficial femoral-popliteal vein was resected for use as a femoropopliteal bypass graft (25 legs) with a control group of 22 legs in which a saphenous vein or polytetrafluoroethylene graft was used for femoropopliteal bypass. No significant differences were found in age or sex distribution, time from surgery to the venous test, side of bypass, or the incidence of postoperative extremity swelling, either early or late. A mild but significant calf enlargement was observed in the deep vein group (p less than 0.05), and a pattern consistent with venous outflow obstruction was shown by plethysmography in 21 of 25 extremities (84%) in which a deep vein was used for femoropopliteal bypass but in only 11 of 22 (50%) control extremities (p less than 0.02). It is concluded that a lower extremity deep veins should be considered as a suitable replacement for a large vein or, when superficial vein is not available, as an infrainguinal arterial substitute.

Aged↗

Risk factors associated with acute lower extremity ischemia after coronary revascularization.

Acute lower extremity ischemia (ALEI) is a recognized complication of coronary revascularization that can lead to emergent lower extremity revascularization, amputation, and death. Patients with correctable coronary artery disease have a high incidence of lower extremity arterial occlusive disease (AOD). But, despite the known high correlation between AOD and coronary artery disease, the status of the lower extremity vasculature in patients undergoing coronary revascularization may be overlooked until the lower extremity becomes profoundly ischemic. Data from a retrospective review of 35,000 coronary revascularization procedures identified 55 patients who developed ALEI, subsequent to their cardiac procedures. Risk factors for ALEI included femoral artery instrumentation, previous coronary revascularization, hemodynamic instability, and documented AOD. Means of identifying patients at risk for ALEI are discussed.

Acute Disease↗

The C-terminal sterile alpha motif and the extreme C terminus regulate the transcriptional activity of the alpha isoform of p73.

p73, a member of the p53 family, is expressed from two separate promoters, generating TA and DeltaN variants. Each variant potentially encodes at least seven alternatively spliced isoforms (alpha-eta). Interestingly, we and others have shown that the alpha isoform of p73 has a weaker transcriptional activity than the beta isoform. Because the alpha isoform has an extended C terminus consisting of a sterile alpha motif (SAM) and an extreme C terminus, it appears that the C terminus is inhibitory. However, how the C terminus inhibits the transcriptional activity of p73 has not been determined. Here, we found that both the SAM and the extreme C terminus exert their inhibitory activity by preventing the accessibility of p300/CBP to the activation domain in p73. Specifically, we showed that the SAM and the extreme C terminus together or individually are capable of repressing the function of p73 activation domain, but neither interacts directly with the activation domain, or suppresses the DNA-binding activity, of the p73 protein. We also showed that the intact state of the SAM and the extreme C terminus is essential for their inhibitory functions such that a small deletion of either the SAM or the extreme C terminus abolishes its inhibitory activity. Furthermore, we showed that both inhibitory domains in the C terminus are capable of suppressing the function of a cis heterologous activation domain from p53 or Gal4. Finally, we showed that both inhibitory domains suppress the ability of p73 to interact with the transcriptional coactivators p300/CBP that are necessary for the initiation of transcription.

Amino Acid Motifs↗

Primary structure of selected archaeal mesophilic and extremely thermophilic outer surface layer proteins.

The archaea are recognized as a separate third domain of life together with the bacteria and eucarya. The archaea include the methanogens, extreme halophiles, thermoplasmas, sulfate reducers and sulfur metabolizing thermophiles, which thrive in different habitats such as anaerobic niches, salt lakes, and marine hydrothermals systems and continental solfataras. Many of these habitats represent extreme environments in respect to temperature, osmotic pressure and pH-values and remind on the conditions of the early earth. The cell envelope structures were one of the first biochemical characteristics of archaea studied in detail. The most common archaeal cell envelope is composed of a single crystalline protein or glycoprotein surface layer (S-layer), which is associated with the outside of the cytoplasmic membrane. The S-layers are directly exposed to the extreme environment and can not be stabilized by cellular components. Therefore, from comparative studies of mesophilic and extremely thermophilic S-layer proteins hints can be obtained about the molecular mechanisms of protein stabilization at high temperatures. First crystallization experiments of surface layer proteins under microgravity conditions were successful. Here, we report on the biochemical features of selected mesophilic and extremely archaeal S-layer (glyco-) proteins.

Amino Acid Sequence↗

Comparison of clearance of particles inhaled with bolus and extremely slow inhalation techniques.

Ten healthy nonsmokers inhaled 6-microm (aerodynamic diameter) Teflon particles labelled with 111In twice, once with the shallow bolus technique (volumetic lung depth 76+/-20 mL ([+/- SD]) and once with the extremely slow inhalation technique (0.05 L/s). The radioactivity in the lungs was measured at 1 and 24 hours as well as at 1, 2, and 3 weeks after both inhalations. The 24-hour lung retention a percentage of lung deposition was significantly lower for the bolus inhalation, 46%+/-9% (+/- SD) than for the extremely slow inhalation, 56%+/-11%. The retention after 21 days as a percentage of the 24-hour retention was 55%+/-9% for the shallow bolus inhalation and 56%+/-10% for the extremely slow inhalation. Also within the subjects, clearance was similar for the 2 modes of inhalation. Deposition of particles inhaled with the 2 modes of inhalation was calculated with 2 model, one being based on Monte (Carlo particle transport together with an asymmetric lung model. Deposition predicted with this model agreed well with the experimental data under the assumption that there are large retained fractions only in small ciliated airways (bronchioli) and not in large ones. For the bolus inhalation, the model predicted 43% to 50% deposition in the bronchial (BB) region of initial lung deposition, 33% to 38% in the bronchiolar (bb) region, and 16% to 22% in the alveolar region. For the extremely slow inhalation, the model predicted 31% to 34% deposition in the BB region, 45% to 47% in the bb region, and 21% to 22% in the alveolar region. In addition, it predicted about the same ratio between bb and alveolar depositions for the 2 modes of inhalation. Thus, both the experimental and theoretical data indicate that the shallow bolus particles to a considerable extent reach both the bb and the alveolar regions and that they do that at about the same extent as the particles inhaled extremely slow. This conclusion is concerning the experimental data based on the assumption that there are no large retained fractions in the BB region. Another interpretation of the similar clearance for the two modes of inhalation is that there are large retained fractions in both the BB and the bb regions and that individual charactristics of clearance of these fractions are of importance rather than the site of deposition.

Administration, Inhalation↗

Mood responses to athletic performance in extreme environments.

Competition at elite level can require athletes to perform optimally in extreme environmental conditions. This review focuses on mood responses in such conditions and proposes practical guidelines for those working with athletes. Different environments are considered, including altitude and extreme heat and cold. Performing in extreme heat, cold or at altitude can produce a stress response characterized by increased negative mood and relatively poor performance. Positive adaptations to extreme conditions can be accelerated, but the rate of adaptation appears to be highly individualized. Monitoring mood responses to training under normal conditions provides a basis for identifying the psychological effects of extreme conditions. It is suggested that practitioners carefully monitor the interplay between vigour, fatigue and depressed mood. Reductions in vigour and increases in fatigue are normal responses to hard training, but other aspects of mood disturbance, especially symptoms of depressed mood--however small--may be indicative of a maladaptive response, and practitioners should consider intervening when such symptoms first appear.

Acclimatization↗

Extremely low frequency magnetic fields and the promotion of H2O2-induced cell death in HL-60 cells.

PURPOSE: To test whether exposure to an extremely low frequency magnetic field (60 Hz, 5 mT) affects hydrogen peroxide (H2O2)-induced cell death in human leukaemia HL-60 cells. MATERIALS AND METHODS: Cells were treated with H2O2 with or without exposure to an extremely low frequency magnetic fields. Viable cells, apoptotic and necrotic cells were determined by annexin V flow cytometry assay. The levels of apoptosis-related proteins (caspase-3, caspase-7, Bcl-2 and Bax) and poly(ADP-ribose) polymerase were detected using Western blotting. RESULTS: Simultaneous treatment with exposure to the magnetic field and H2O2 (85 or 100 microM) for 24 h increased the number of apoptotic and necrotic cells significantly, and significantly decreased the number of viable cells compared with cells treated with H2O2 alone. The protein levels of Bax and Bcl-2 showed no differences between H2O2-treated cells and those treated with both H2O2 and an extremely low frequency magnetic field. Exposure to the magnetic field also had no effect on H2O2-induced caspase-3 activation. However, the protein levels of active caspase-7 in cells simultaneously exposed to an extremely low frequency magnetic field and H2O2 for 2 and 8 h was higher than that of H2O2 treatment alone. In addition, simultaneous exposure to an extremely low frequency magnetic field and H2O2 caused poly(ADP-ribose) polymerase cleavage and induced early inactivation at 2 h, while H2O2 treatment alone did not produce this effect until 4 h. CONCLUSIONS: The data suggest that although the magnetic field itself cannot induce apoptosis and necrosis, it exerts a promoting effect on H2O2-induced cell death, and it demonstrates that caspase-7 as well as poly(ADP-ribose) polymerase might be involved in this process.

Apoptosis↗

Effect of walking speed on lower extremity joint loading in graded ramp walking.

Lower extremity joint loading during walking is strongly affected by the steepness of the slope and might cause pain and injuries in lower extremity joint structures. One feasible measure to reduce joint loading is the reduction of walking speed. Positive effects have been shown for level walking, but not for graded walking or hiking conditions. The aim of the study was to quantify the effect of walking speed (separated into the two components, step length and cadence) on the joint power of the hip, knee and ankle and to determine the knee joint forces in uphill and downhill walking. Ten participants walked up and down a ramp with step lengths of 0.46, 0.575 and 0.69 m and cadences of 80, 100 and 120 steps per minute. The ramp was equipped with a force platform and the locomotion was filmed with a 60 Hz video camera. Loading of the lower extremity joints was determined using inverse dynamics. A two-dimensional knee model was used to calculate forces in the knee structures during the stance phase. Walking speed affected lower extremity joint loading substantially and significantly. Change of step length caused much greater loading changes for all joints compared with change of cadence; the effects were more distinct in downhill than in uphill walking. The results indicate that lower extremity joint loading can be effectively controlled by varying step length and cadence during graded uphill and downhill walking. Hikers can avoid or reduce pain and injuries by reducing walking speed, particularly in downhill walking.

Acceleration↗

A linkage strategy for detection of human quantitative-trait loci. II. Optimization of study designs based on extreme sib pairs and generalized relative risk ratios.

We are concerned here with practical issues in the application of extreme sib-pair (ESP) methods to quantitative traits. Two important factors-namely, the way extreme trait values are defined and the proportions in which different types of ESPs are pooled, in the analysis-are shown to determine the power and the cost effectiveness of a study design. We found that, in general, combining reasonable numbers of both extremely discordant and extremely concordant sib pairs that were available in the sample is more powerful and more cost effective than pursuing only a single type of ESP. We also found that dividing trait values with a less extreme threshold at one end or at both ends of the trait distribution leads to more cost-effective designs. The notion of generalized relative risk ratios (the lambda methods, as described in the first part of this series of two articles) is used to calculate the power and sample size for various choices of polychotomization of trait values and for the combination of different types of ESPs. A balance then can be struck among these choices, to attain an optimum design.

Female↗

Geropsychological problems in medical rehabilitation: dementia and depression among stroke and lower extremity fracture patients.

BACKGROUND: Although stroke and lower extremity fracture are often viewed as distinct medical rehabilitation conditions, they share similarities in that they are both experienced primarily among older adults, and are often accompanied by gero-psychological problems such as dementia and depression. In spite of these similarities, actual comparisons of these prevalence rates have been rare in the previous literature, most likely due to obvious differences in the nature of the injuries involved (neurological vs. peripheral injury). METHODS: One hundred and one stroke and 198 lower extremity fracture patients were assessed with neuropsychological tests from the Normative Studies Research Project test battery. The prevalence rates of dementia and depression were then compared between these two patient groups. RESULTS: Overall, 34.7% of stroke and 27.8% of lower extremity fracture patients met the criteria for dementia. In addition, 33.3% of stroke and 25.1% of lower extremity fracture patients scored in the depressed range on the Geriatric Depression Scale. The prevalence rates for dementia and depression did not differ significantly between these two patient groups. CONCLUSIONS: Although rehabilitation efforts focus mainly upon the primary diagnoses of geriatric patients, these findings suggest that stroke and lower extremity fracture should be considered within the context of the geriatric issues (e.g., dementia, depression, and comorbid medical illness) which accompany them.

Activities of Daily Living↗

Lower extremity performance in nondisabled older persons as a predictor of subsequent hospitalization.

BACKGROUND: This study examines, in initially nondisabled older persons, the impact of reduced lower extremity performance on subsequent hospitalizations. METHODS: A 4-year prospective cohort study was conducted among 3381 persons, aged 71 years and older, who initially reported no disability. At baseline, lower extremity performance was measured by an assessment of standing balance, a timed 2.4-m walk, and a timed test of rising from a chair five times. Data on subsequent hospital admissions and discharge diagnoses over 4 years were obtained from the Medicare database. RESULTS: During the follow-up period, nondisabled persons with poor lower extremity performance spent significantly more days in the hospital (17.7 days) than those with intermediate and high performance (11.6 and 9.7 days, respectively). Poor lower extremity performance in nondisabled persons significantly predicted subsequent hospitalization over 4 years (relative risk for hospitalization in those with poor vs high performance: 1.78; 95% confidence interval, 1.45-2.17). This increased hospitalization risk could not be explained by several indicators of baseline health status. Increased hospitalization risks were especially found for geriatric conditions, such as dementia, decubitus ulcer, hip fractures, other fractures, pneumonia, dehydration, and acute infections. CONCLUSIONS: Even in persons who are currently nondisabled, a simple measure of lower extremity performance is predictive of subsequent hospitalization, especially for geriatric conditions.

Aged↗

Prevalence of upper extremity symptoms and possible risk factors in workers handling paper currency.

The prevalence of upper extremity symptoms in the workforce is high, particularly in industries characterized by forceful, repetitive or awkward movements. A study was undertaken to assess the prevalence of upper extremity symptoms in bank workers in a paper currency processing operation and to examine the role of possible risk factors for these complaints. Thirty-nine workers of a total workforce of 47 were assessed with a questionnaire and physical examination. The questionnaire collected information about demographics, health status, symptom reporting, psychosocial work stressors and other work exposure characteristics. Overall, 59% of the workers reported having significant work-related upper extremity musculoskeletal symptoms in the preceding year, including 49% with neck and shoulder symptoms and 49% with arm and wrist symptoms. In this study the key predictive factor for upper extremity musculoskeletal symptoms was psychological job demands. The workers had similar ergonomic stressors (with little gradient of exposure) and therefore our results do not contradict the importance of ergonomic factors in the development of upper extremity symptoms. However, the results do suggest that within a group exposed to similar ergonomic stressors, psychological job demands may be an important factor associated with musculoskeletal symptoms.

Adult↗

Fluctuating asymmetry of morphometric characters in house mice: the effects of age, sex, and phenotypical extremeness in a randombred population.

Fluctuating asymmetry (FA) was calculated for nine paired morphometric characters in a randombred population of house mice in order to assess the effects of age, sex, and phenotypical extremeness. FA did not significantly vary between sexes for any of the characters, and age proved to be significant only for innominate length. Additionally, FA values in high extreme individuals and low extreme individuals were compared to those for intermediate individuals to discover whether extreme individuals showed increased fluctuating asymmetry (decreased developmental stability) due to increased levels of homozygosity. Differences in fluctuating asymmetry magnitudes were found between the groups, although the extreme individuals did not consistently show increased fluctuating asymmetry and FA differences also showed no significant association with the level of heritability of each character. Potential reasons for these findings are discussed.

Aging↗

Lower extremity weight bearing under various standing conditions in independently ambulatory patients with hemiparesis.

The purpose of this investigation was to determine if differences exist in weight bearing through the paretic and nonparetic lower extremities during various bilateral standing conditions. We used digital scales to measure weight bearing among 25 hemiparetic patients as they stood comfortably, as they alternately shifted as much weight as possible to each lower extremity, and as they alternately stood with each foot on a step. Patients bore significantly more weight (p less than .001) on their nonparetic than on their paretic lower limb during comfortable standing. They bore significantly more weight on their nonparetic extremity when shifting as much weight as possible to it than they did on their paretic extremity when shifting as much weight as possible to it (p less than .001). They bore significantly more weight (p less than .001) on the lower extremity that was not on the step during step standing. For patients comparable to those tested, standing with one lower limb on a 17-cm step should facilitate weight bearing through the contralateral lower limb.

Adolescent↗

The role of free tissue transfer following oncologic resection in the lower extremity.

The current treatment of extremity sarcomas is multimodal, consisting of limb-sparing surgery, adjuvant radiotherapy, and/or chemotherapy. This approach has decreased the need for amputations and increased the demand for coverage of large composite defects. To date, the role of microsurgery in lower extremity reconstruction after oncologic resection has not been well defined. This study reviews a single center's experience with free tissue transfer for reconstruction of the lower extremity after oncologic resection. Fifty-nine free flaps were performed in 57 patients over a 5-year period. Forty-six patients (78%) underwent primary reconstruction and 35 patients (61%) received adjuvant therapy. Overall flap success rate was 96.6%. Most flaps were soft-tissue types including musculocutaneous (78%), skin only (11%), and muscle plus skin graft (4%). Osteocutaneous flaps were uncommon. There were major complications in 12% and minor complications in 7%. This study demonstrates that free tissue transfer for lower extremity reconstruction following oncologic resection has a high success rate that is similar to other free flap applications. It has become an integral part of lower extremity sarcoma management. Free flaps permit uninterrupted adjuvant therapy and enhance the efficacy of limb salvage surgery.

Adult↗

Microsurgical reconstruction of the lower extremity using the 3M microvascular coupling device in venous anastomoses.

Microsurgical reconstruction of the lower extremity presents a difficult problem to plastic surgeons; the rate of failure is higher than any other anatomical site. We reviewed our recent experience with lower extremity microsurgical reconstruction using the 3M vascular coupling device. We believe the excellent patency rate of the coupler may minimize the well-described problem of venous thrombosis in this challenging group of patients. This study involves a consecutive series of 11 patients who presented for reconstructive microsurgery of the lower extremity at NYU Medical Center hospitals between June 1 and September 1, 1994. Ten of 11 patients had free flap transfer to traumatic lower extremity injuries, whereas the remaining reconstruction was in a diabetic individual with a chronic wound. Fifteen microvascular venous anastomoses were performed; all but 1 was performed using the 3M coupler. Our experience with 11 patients, involving 14 mechanically coupled venous anastomoses, demonstrated successful use of the coupler. No intraoperative or postoperative vascular complications occurred. The overall success rate of the 3M coupler for venous anastomoses was 100%, and all microvascular free flaps were successful. We recommend using the 3M coupling device for venous anastomoses during reconstructive microsurgery of the lower extremity. Our series demonstrates the safety and effectiveness of the 3M coupler in this challenging group of patients. In addition, a secondary benefit of the 3M coupler is a significant reduction in operative time.

Adolescent↗

Phlegmasia cerulea dolens of the upper extremity.

Phlegmasia cerulea dolens (PCD) is the term describing the painful venous congestion that results from near-total venous occlusion of a limb. It is unusual in the lower extremity but is decidedly rare in the upper extremity with only a handful of cases reported in the literature. PCD of the upper extremity usually occurs in patients with significant comorbid conditions such as severe cardiac failure or advanced malignancy. PCD of the upper extremity is associated with substantial morbidity and mortality. We present a case of upper extremity PCD in an elderly man with a complex medical history, complicated clinical course, and poor outcome that is typical for this rare disease.

Aged↗

Lower extremity deep vein thrombosis: a prospective, randomized, controlled trial in comatose or sedated patients undergoing femoral vein catheterization.

OBJECTIVES: To determine the rate of lower extremity deep vein thrombosis after the use of femoral catheters in intensive care unit (ICU) comatose or sedated adults. Results were then compared with results of patients undergoing superior vena cava catheterization. DESIGN: Prospective, randomized, controlled, unblinded study. SETTING: A mixed medical/surgical ICU in a university hospital. PATIENTS: Sixty-one comatose or sedated patients admitted to the ICU who underwent central venous catheterization. INTERVENTIONS: Patients were monitored for signs of thrombotic complications. On catheter removal, a lower-extremity bilateral phlebographic examination was performed in each patient. MEASUREMENTS AND MAIN RESULTS: After randomization, 31 patients underwent femoral vein catheterization and 30 patients underwent superior vena cava catheterization, either by axillary (21 patients) or internal jugular vein (10 patients) cannulation. Single lumen polyurethane catheters were inserted for a mean duration of 7.1 +/- 4.6 (SD) days in the femoral vein group and 9.9 +/- 5.5 days in the superior vena cava group (p = NS). No patient had clinical signs of leg venous thrombosis or pulmonary embolism during the study period. In each patient, lower extremity bilateral phlebography was performed at the time of catheter removal. Leg phlebographies were normal in 18 (60%) patients in the femoral vein group and 26 (84%) patients in the superior vena cava group. Fibrin sleeves which developed around the femoral catheters were seen in seven (23.3%) patients in the femoral vein group and in no patients in the superior vena cava cannulation group. Three patients had femoral vein thrombosis, two (6.6%) patients in the femoral vein group (two nonobstructive thromboses, adherent to the common femoral vein wall) and one (3.0%) patient in the superior vena cava group (nonobstructive thrombosis which developed in the superficial femoral vein) (p = NS). Lower deep extremities thrombosis developed in five (16.7%) patients in the femoral vein group and in five (16%) patients in the superior vena cava group (p = NS). CONCLUSIONS: Femoral vein catheterization with a polyurethane catheter is associated with a lower rate of extremity deep vein thrombosis which is similar to the rate observed after superior vena cannulation in comatose or sedated patients. Femoral vein thrombosis was observed at a rate of 6.6% after femoral vein cannulation and a rate of 3% after superior vena cava cannulation. Given the acceptable rate of this clinically important complication, femoral vein cannulation offers an attractive alternative to insertion via the vena cava in the critically ill.

APACHE↗