Evidence for widespread changes in the structure, composition, and fire regimes of western North American forests.

Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion. The cumulative results of more than a century of research document a persistent and substantial fire deficit and widespread alterations to ecological structures and functions. These changes are not necessarily apparent at all spatial scales or in all dimensions of fire regimes and forest and nonforest conditions. Nonetheless, loss of the once abundant influence of low- and moderate-severity fires suggests that even the least fire-prone ecosystems may be affected by alteration of the surrounding landscape and, consequently, ecosystem functions. Vegetation spatial patterns in fire-excluded forested landscapes no longer reflect the heterogeneity maintained by interacting fires of active fire regimes. Live and dead vegetation (surface and canopy fuels) is generally more abundant and continuous than before European colonization. As a result, current conditions are more vulnerable to the direct and indirect effects of seasonal and episodic increases in drought and fire, especially under a rapidly warming climate. Long-term fire exclusion and contemporaneous social-ecological influences continue to extensively modify seasonally dry forested landscapes. Management that realigns or adapts fire-excluded conditions to seasonal and episodic increases in drought and fire can moderate ecosystem transitions as forests and human communities adapt to changing climatic and disturbance regimes. As adaptation strategies are developed, evaluated, and implemented, objective scientific evaluation of ongoing research and monitoring can aid differentiation of warranted and unwarranted uncertainties.

Predicting forest floor and woody fuel consumption from prescribed burns in southern and western pine ecosystems of the United States.

We present pre-burn biomass and consumption data from 60 prescribed burns in the southeastern and western United States. The datasets include pre-burn biomass in Mg/ha by fuel category: herbaceous fuels, shrubs, 1-hr, 10-hr, 100-hr, 1000-hr, 10,000-hr, and > 10,000-hr downed wood, litter and duff. Pre-burn depth (cm) and reduction (cm) are provided for litter and duff layers. Day-of-burn fuel moistures and weather are also listed by site.

Patients on chronic peritoneal dialysis for ten years or more in North America.

Thirty-six patients on peritoneal dialysis (PD) for more than ten years in six North American centers were analyzed retrospectively. In the six centers, the percentage of patients surviving for more than ten years varied between 0.8% and 7.3%. The study group included 27 females and 9 males aged 38.6 +/- 14.2 years [mean +/- standard deviation (SD)] at the start of treatment. Of the 36 patients, 28 were Caucasian. The most common cause of end-stage renal disease (ESRD), present in 12 patients, was chronic glomerulonephritis. Only 4 patients had diabetes. At the beginning of the study, 19 patients had hypertension (the most common comorbid condition); 11 had no comorbid conditions at the start. Creatinine clearance at the start was 4.12 +/- 3.5 mL per minute, and the mean duration to anuria was 51 +/- 25 months. Mean initial body weight was 55 +/- 9 kg, and mean body surface area was 1.5 +/- 0.2 m2. Serum albumin levels showed an increase from 33.8 +/- 3.6 g/L at the start of the study to 38.2 +/- 3.9 g/L at the end. Hospitalization rate was low at 0.5 +/- 0.3 admissions per patient-year, and duration of hospitalization was 4.8 +/- 3.7 days per patient-year. Peritonitis was the most common cause of hospitalization. The mean peritonitis rate was 1 episode every 52 +/- 48 patient-months. There were 36 catheter changes in 18 patients; 16 patients had a single PD catheter throughout the period of study. Autonomous hyperparathyroidism was the most common long-term complication. At the end of the study period, 11 patients were still on PD, 9 had died, 5 had been transferred to hemodialysis (HD), 1 was alive with a functioning allograft, and 1 was lost to follow-up. We conclude that patients who survive longer than ten years on PD are most likely to be young Caucasian females, small in body size, who are non diabetic, with few comorbid conditions. These long-term survivors have few hospitalizations, and their peritonitis rate is low. In this group of patients, severe autonomous hyperparathyroidism is the most common long-term complication.

Major and minor risk factors for cardiovascular disease in peritoneal dialysis.

All uremic patients have multiple risk factors for CAD including in many, the conditions that caused their ESRD--for example, diabetes and hypertension. conventional risk factors--for example, dyslipidemia and hyperhomocysteinemia. risk factors that are unique to uremia--for example, calcium and phosphate abnormalities. PD patients have particular risk with respect to their lipid status and hyperinsulinemia. Many of these risks are potentially modifiable, but evidence does not exist to assess the impact of treatment on clinical outcomes. Therefore, current decisions for therapy directed at risk factor modification must be made on an individual basis.

Decision process about options in renal therapy substitution: selection versus election.

No renal replacement therapy stands alone. Hemodialysis, peritoneal dialysis and transplantation each have a role to play in the care of our patients. When one fails, another can replace that modality. Patients and staff should be counselled accordingly. The responsibility of healthcare workers is to try to best match the medical condition and lifestyle of the patients with the renal replacement therapy available. Furthermore the patients should have sufficient information to be able to make these decisions wisely.

Factor structure of the College Adjustment Scales.

The present study examined the underlying structure of the College Adjustment Scales via principal components analysis. A correlation matrix of the nine subscales showed significant multicolinearity. A subsequent principal components analysis demonstrated that one factor accounted for 57% of the total variance and that the majority of subscales were moderately correlated with this single factor. The results suggest that the College Adjustment Scales may measure the same underlying construct and that the clinical distinctions implied by subscale scores should be regarded with caution. Conclusions are constrained by sample size and demographic characteristics, but the results suggest the need for further empirical validation of the College Adjustment Scales, which may be useful in college counseling centers.

Decision process about options in renal therapy substitution: selection versus election

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Major and minor risk factors for cardiovascular disease in continuous ambulatory peritoneal dialysis patients.

Uremia in general and peritoneal dialysis in particular bring with them risk factors for the development of cardiovascular disease. These factors include multiple lipid abnormalities, hyperhomocysteinemia, abdominal obesity, chronic inflammation, hypoalbuminemia, oxidative stress, and AGE formation. When these are combined with conventional risk factors, one can appreciate why the incidence of cardiovascular disease is so high in peritoneal dialysis patients. Treatment strategies should address each of these risks appropriately.

The costs of dialysis in Canada.

In summary, Canada enjoys a publicly funded healthcare system which is the second most costly in the world. The treatment rate for renal replacement therapy is comparable with countries in Europe but falls short of that in the United States and Japan. With respect to costs, peritoneal dialysis is a cheaper option than haemodialysis. The major costs in peritoneal dialysis are supply related and the major costs in haemodialysis are labour and supplies. A treatment modality change includes a set of costs which makes the most cost-effective therapy in almost cases a therapy that can be successfully maintained.

Peritoneal dialysis and haemodialysis: are they comparable?

It is difficult to make adequate comparisons between peritoneal and haemodialysis. Survival studies show somewhat different results from country to country. In Canada, peritoneal dialysis appears to have some advantage over haemodialysis using the Cox regressional analysis. Intention-to-treat survival curves show no difference. With respect to the quality of life, it is difficult to demonstrate significant differences. Cost differences are country dependent. For any given patient, where medical considerations heavily favour one modality over another, one can safely presume that either haemodialysis or peritoneal dialysis can be successfully employed in managing the patient.

Cardiovascular disease in peritoneal dialysis.

Cardiovascular morbidity and mortality remain high in ESRD patients. Lipid abnormalities in CAPD may be more important than in hemodialysis. Vessel calcification may have a role in atherosclerotic heart disease, but this is only an inference from several clinical observations, and it remains to be defined more clearly as a risk factor. Left ventricular hypertrophy is frequent in this patient population, and is associated with specific clinical patterns and an increased risk of death. Erythropoietin treatment of anemia and tight blood pressure controls have proved to help in reversing severe left ventricular hypertrophy. Finally, we describe a syndrome of the hypertrophic, high cardiac output hemodialysis heart, which is characterized by a high cardiac output in hemodialysis patients. It is associated with left ventricular hypertrophy and eventually right ventricular hypertrophy with tricuspid insufficiency. This may require fistula revision and even a switch peritoneal dialysis.

Socioeconomic and health-care policies and peritoneal dialysis.

1. All ESRD treatments is expensive and a modality change adds considerably to that expense. 2. Ideally, the cost of ESRD therapy should be reported as the cost incurred for all aspects of the treatment to the health-care system. 3. Most studies show peritoneal dialysis to be less expensive than hemodialysis, but this can vary depending on the local costs of supplies and labor. 4. Strategic decisions with regard to new innovations should be made after a full analysis of all of the involved costs and savings that the innovation might introduce. 5. Economic factors and reimbursement rates appear to have an important impact on modality selection.

Successful pregnancy complicated by peritonitis in a 35- year old CAPD patient.

A 35-year old woman conceived six months after initiating continuous ambulatory peritoneal dialysis (CAPD). A medical plan was developed to give the patient adequate dialysis for a 1.5 g/kg/day protein intake. In addition, alterations in calcium, magnesium, and erythropoietin administration were required to reach the objectives set by the obstetrical/renal team. Three weeks prior to delivery, an amniotic leak developed, and vaginal cultures were positive for Escherichia coli. Oral amoxicillin was administered (500 mg per os q.i.d.) until the day of delivery. A 1545-g baby girl was delivered by cesarean section at 32 weeks. Five days postpartum the patient developed severe peritonitis, which subsequently grew E. coli. The patient fully recovered from the peritonitis, but catheter removal was required. Successful pregnancy can be expected on CAPD, and adequacy can be achieved with aggressive dialysis. Cesarean section delivery should probably be accompanied by full peritonitis therapy.