Forest restoration potentials of coal-mined lands in the eastern United States.

The Appalachian region in the eastern United Sates is home to the Earth's most extensive temperate deciduous forests, but coal mining has caused forest loss and fragmentation. More than 6000 km in Appalachia have been mined for coal since 1980 under the Surface Mining Control and Reclamation Act (SMCRA). We assessed Appalachian areas mined under SMCRA for forest restoration potentials. Our objectives were to characterize soils and vegetation, to compare soil properties with those of pre-SMCRA mined lands that were reforested successfully, and to determine the effects of site age on measured properties. Soils were sampled and dominant vegetation characterized at up to 10 points on each of 25 post-SMCRA mines. Herbaceous species were dominant on 56%, native trees on 24%, and invasive exotics on 16% of assessed areas. Mean values for soil pH (5.8), electrical conductivity (0.07 dS m(-1)), base saturation (89%), and coarse fragment content (50% by mass) were not significantly different from measured levels on the pre-SMCRA forested sites, but silt+clay soil fraction (61%) was higher, bicarbonate-extractable P (4 mg kg(-1)) was lower, and bulk density (1.20 g cm(-1)) was more variable and often unfavorable. Pedogenic N and bicarbonate-extractable P in surface soils increased with site age and with the presence of weathered rocks among coarse fragments. Our results indicate a potential for many of these soils to support productive forest vegetation if replanted and if cultural practices, including temporary control of existing vegetation, soil density mitigation, and fertilization, are applied to mitigate limitations and aid forest tree reestablishment and growth.

The effects of peripheral vascular disease with osteomyelitis in the diabetic foot.

BACKGROUND: Osteomyelitis in the diabetic foot is a difficult problem with multiple etiologies. The effects of peripheral vascular disease, neuropathy, and repetitive trauma all interact to produce complex lesions with exposed bone, surrounding cellulitis, and gangrenous changes. METHODS: We performed a retrospective study over a 14-year period at a community hospital looking at osteomyelitis in the diabetic foot. We looked at the contributing factors, organisms involved, most common locations, physical findings, and surgical procedures necessary to treat this condition. The purpose of the study was to determine the incidence and effect of peripheral vascular disease in diabetic patients with foot ulcers. RESULTS: There were a total of 150 patients requiring 278 hospitalizations over the 14-year period who represented 14% of all diabetic admissions. A total of 438 surgical procedures were necessary in these patients, with the most common being debridement (39%) and toe amputation (19%). There were 6 deaths (4%) in this series, and leg amputation was necessary in 21 patients (14%). A vascular bypass was necessary for healing and limb salvage in 36 patients (24%). Most of the bypasses (85%) were with autogenous tissue to the distal leg in order to limit the extent of amputation and to preserve a functional limb. CONCLUSION: Ischemia is often a contributing factor in the diabetic foot ulcer that must be recognized and treated to avoid prolonged hospitalization, spreading infection, and unnecessary amputation.

The origin of lower extremity deep vein thrombi in acute venous thrombosis.

BACKGROUND: It has been taught that most deep venous thromboses (DVT) begin in the deep veins of the calf and propagate proximally. The duplex ultrasound scan, with its noninvasive characteristics and accuracy, has brought this premise into question. The purpose of this study was to determine the pattern and distribution of acute DVT as well as the different types of thrombi. METHODS: We performed a retrospective review of all duplex scans ordered for a diagnosis of acute lower extremite DVT at a 200-bed hospital over a 5-year period. RESULTS: There were 3,585 examinations performed on 2,654 patients. There were 461 patients (17.4%) with a venous thrombosis. Four types of venous thrombosis were identified: an isolated thrombosis in one venous segment (34%), a thrombosis extending over two or more contiguous segments (52%), multiple thromboses in noncontiguous segments (8%), and bilateral thrombi in different locations (6%). CONCLUSION: Calf vein thrombi represented 24% of all DVT. Thrombi in the major veins of the thigh and popliteal space without calf involvement were present in 49% of all DVT. The data in this paper indicate that most significant deep venous thromboses do not begin in the calf but instead arise in the proximal thigh or groin.

Selective use of the duplex scan in diagnosis of deep venous thrombosis.

BACKGROUND: The introduction of managed care, with its emphasis on cost containment, makes it of paramount importance that all tests ordered be specific, selective, and appropriate. METHOD: The data concerning patients who underwent a duplex scan to determine the presence of deep venous thrombosis (DVT) over a 68-month period, were reviewed in order to determine if the test was ordered appropriately. The symptoms that prompted the test, type of physician ordering the test, and demographic data for both the patients who tested positive and negative were tabulated. RESULTS: A total of 2,841 duplex scans were ordered over a 68-month period for presumptive diagnosis of DVT of an extremity. A total of 524 (18%) scans were positive for thrombosis; however, 27% (144) of these were superficial or a small isolated thrombus in the calf or forearm. Thus, only 380 studies, or 13% of the total scans ordered, were positive for a major DVT requiring treatment. The only symptoms consistently found in the positive group were pain, edema, dyspnea, and a history of DVT. Of the types of physicians ordering the test, emergency department physicians were least specific, with only 12% of the scans ordered being positive for DVT; surgeons were more selective and had a 19% positive rate, while internal medicine physicians had a 20% positive rate. CONCLUSION: The duplex scan allows the physician the ability to easily diagnose venous thrombosis, but its indications need to be more carefully guided by history, physical examination, risk factors, and logic to enhance its use and effectiveness. This study analyzes the risk factors and symptoms involved in order to assist the clinician in determining when the duplex scan is indicated.

Diagnosis of acute myocardial infarction from two measurements of creatine kinase isoenzyme MB with use of nonparametric probability estimation.

By using bivariate probability estimation for the diagnosis of acute myocardial infarction (AMI) we show how to overcome the difficulties encountered for patients whose clinical presentation is atypical and those encountered when multiple isoenzyme determinations are treated by univariate methods. We use the values for creatine kinase isoenzyme MB measured at the time of admission and 12 h later to estimate the Bayes factors in favor of AMI. The Bayes factors are compiled into a table that the clinician can use to estimate the posterior probability that a patient has AMI. The table of Bayes factors is based on data for a sample of 802 non-AMI patients and 180 AMI patients. Further to validate the method, we randomly chose 200 of the non-AMI and 50 of the AMI patients as an evaluation sample, then used the remaining 602 non-AMI and 130 AMI patients to recompute the Bayes factors. These Bayes factors were used to find the probability of AMI for each of the 250 patients in the evaluation sample. The method resulted in only one false positive and no false negatives. For the misclassified patient the measurements at admission and 12 h later were 1 and 11 U/L; the posterior odds were 15 to 1 in favor of AMI, but in fact the patient was non-AMI.

Influence of low temperature on rate of development of Meloidogyne incognita and M. hapla larvae.

Development of Meloidogyne incognita and M. hapla larvae in clover roots was studied at 20, 16, 12, and 8 C in growth chambers and in the field from fall through spring, in North Carolina. Larvae of both species invaded roots and developed at 20, 16, and 12 C, but not at 8 C. The time necessary to complete the larval stages at each temperature was determined. The minimal temperature for development of M. incognita larvae was 10.08 C and 8.8 C for M. hapla larvae. In the field, soil temperature at 10 cm deep was favorable for development of larvae until the end of November, and again from February on. All stages of the nematodes survived freezing temperatures in the roots. Reproduction of both species was evident in March or Apri1 after inoculation and accumulation of 8,500 to 11,250 degree-hours.