An innovative approach for locating and evaluating subsurface pathways for nitrogen loss.

Fundamental watershed-scale processes governing chemical flux to neighboring ecosystems are so poorly understood that effective strategies for mitigating chemical contamination cannot be formulated. Characterization of evapotranspiration, surface runoff, plant uptake, subsurface preferential flow, behavior of the chemicals in neighboring ecosystems, and an understanding of how crop management practices influence these processes are needed. Adequate characterization of subsurface flow has been especially difficult because conventional sampling methods are ineffective for measuring preferential flow of water and solutes. A sampling strategy based on ground-penetrating radar (GPR) mapping of subsurface structures coupled with near real-time soil moisture data, surface topography, remotely sensed imagery, and a geographic information system (GIS) appears to offer a means of accurately identifying subsurface preferential flow pathways. Four small adjacent watersheds draining into a riparian wetland and first-order stream at the USDA-ARS Beltsville Agricultural Research Center, Beltsville, MD are being studied with this protocol. The spatial location of some preferential flow pathways for chemicals exiting these agricultural watersheds to the neighboring ecosystems have been identified. Confirmation of the pathways is via examination of patterns in yield monitor data and remote sensing imagery.

Mammography diffusion and trends in late-stage breast cancer: evaluating outcomes in a population.

The purpose of this study was to assess mammography diffusion in a population offered an organized breast cancer screening program, using intervals of 1-3 years, and to evaluate its effect on the late-stage cancer (tumors > or = 3 cm2) rates compared to rates in the surrounding community. We measured "ever-use" of mammography (1986-1992) among women enrollees of a consumer-controlled health care organization (n > or = 60,000/year; ages > or = 40), Group Health Cooperative of Puget Sound (GHC). Among these same women and the surrounding community (n = > or = 745,000/year), we measured late-stage cancer rates. Using unconditional logistic regression, we compared annual rates of ever-use among GHC women ages 40-49 and > or = 50 (1986-1992) and late-stage breast cancer (1983/84-1991/92) among all women. Among all GHC women ages 40 to 49, and 50 years of age and older, 67.4 and 82.8%, respectively, ever-used mammography by 1992. By 1992, approximately one-third of the mammograms among GHC women occurred in each of the three previous years. The rate of late-stage tumors declined significantly in the GHC and non-GHC populations among women 50 years of age and older (P < 0.001) but not among women ages 40 to 49. In conclusion, implementing a system of automated reminders was not sufficient to maximize mammography use in a population. Reductions in late-stage disease occurred among women ages > or = 50, even when regular" was not synonymous with "annual."

Stage, age, comorbidity, and direct costs of colon, prostate, and breast cancer care.

PURPOSE: This study was conducted to evaluate the effect of stage at diagnosis, age, and level of comorbidity (presence of other illness) on the costs of treating three types of cancer among members of a health maintenance organization. METHODS: Among 388,000 members enrolled anytime during 1990 and 1991 in Group Health Cooperative (GHC) of Puget Sound (Washington State), we estimated the total and net direct costs of medical care for colon, prostate, and breast cancers, including both incident (290, 554, and 645 patients, respectively) and prevalent (1046, 1295, and 2299 patients, respectively) cases. We summarized costs for initial, continuing, and terminal phases of care. Net costs were the difference between the costs of the care of each case subject and the average costs of the care for all enrollees without the cancer of interest who were of the same sex and in the same 5-year age group. Differences in estimated total and net costs by stage at diagnosis, age, and comorbidity were separately evaluated using multivariate regression modeling. All P values were two-sided. Comorbidity was based on a score calculated from 1988 pharmacy data. RESULTS: Total costs of initial care increased with stage at diagnosis for colon (P = .0013) and breast (P < .0001) cancer cases, but not for prostate cancer cases. Total initial costs decreased with age for prostate (P = .0225) and breast (P = .0002) cancers but did not change with degree of comorbidity for any of the three cancers. Total continuing medical care costs increased with stage at diagnosis for colon (P < .0001) and breast (P < .0001) cancer cases but not for prostate cancer cases. Total terminal care costs were similar by stage for all three cancers. Net initial costs differed with stage for all three cancers (P < .05). Net continuing care costs increased with stage (P < .0001) and decreased with age (P < .001) for colon and breast cancers but not for prostate cancer. Net continuing care costs decreased with comorbidity for all three cancers (P = .004, P = .011, and P < .0001 for colon, prostate, and breast cancers, respectively). Among regional stage cancers, continuing care costs decreased with age for colon (P < .0017) and breast (P = .033) cancers but not for prostate cancers. CONCLUSIONS: The results show that total costs vary by stage at diagnosis and age, but the patterns of variation differ for each cancer. Costs of cancer are not simply additive to costs of other conditions. IMPLICATIONS: More needs to be done to explore the reasons and implications of age-related cost differences. Cost-effectiveness analyses of cancer control interventions that shift cancer stage distributions may need to consider both the age and comorbidity of the target populations.

Clinical practice and new technology: prostate-specific antigen (PSA).

In response to a marked increase in the use of an available test, Group Health Cooperative of Puget Sound (GHC) evaluated the use of prostatic specific antigen (PSA) as a screening test for prostate cancer. A project team reviewed the literature and determined that PSA did not meet GHC's criteria for screening. An implementation team then developed a comprehensive program to educate staff, facilitate practice change, measure outcomes and provide continuing feedback to physicians. These efforts are described and preliminary reports reported.

The role of circulating immune complexes in the aetiology of polymorphic eruption of pregnancy.

Circulating immune complexes were measured in 35 patients with polymorphic eruption of pregnancy employing three different techniques. No significant abnormalities were detected by the C1q solid phase binding assay and polyethylene glycol precipitation of immunoglobulin G. However, using a solid phase polyclonal rheumatoid factor binding assay, which detects small immune complexes, we demonstrated a significant reduction in the level of circulating immune complexes during the acute stage of the eruption. We suggest that the leakage of small immune complexes through dilated upper dermal vessels may play a role in the aetiology of polymorphic eruption of pregnancy.

Clues to the aetiology and pathogenesis of herpes gestationis.

In a study of twenty-five patients with herpes gestationis we found that 80% possessed the HLA antigen DR3, which confers increased immune responsiveness and a predisposition to 'auto-immune disease'. In five patients the development of herpes gestationis coincided with a change in sexual partner, suggesting that the development of herpes gestationis may depend on exposure to an antigen derived from the father. This might share determinants with a component of the basement membrane zone of skin. Although anti-basement membrane zone antibodies are present in HG it is not clear whether they play a pathogenic role. The infrequency of neonatal involvement and the lack of correlation between immunofluorescence findings and clinical activity in our patients suggested that the antibodies might be a result of tissue damage rather than its cause. Two patients in our study were exceptional in that episodes of herpes gestationis were followed by normal pregnancies. In these patients the relationship of their DR antigens to those of the fetus may have been important in determining whether or not the pregnancy would be affected by herpes gestationis.

Degenerative joint disease in the hip and spine.

Clinical and radiographic assessment of the spine was carried out in 75 patients with osteoarthrosis (OA) of the hip and in 75 controls without hip disease. Radiographic degenerative changes in the spine were more frequent in the patients with OA hips, occurring in both the dorsal and lumbar spine. Moderate or severe changes were found in the dorsal spine in 29 patients with OA hips (compared with 12 controls), and in the lumbar spine in 32 patients with OA hips (compared with 10 controls).

Maternal height and twinning.

Data on maternal height are presented for 307 pairs of newborn twins of known zygosity from Oxford and 267 pairs from Aberdeen and north-east Scotland. The results support the hypothesis that mothers of DZ twins are taller than those of MZ twins. Mothers of MZ twins resemble mothers of singletons in height, whereas mothers of DZ twins are taller.

Immune status in atopic eczema: a survey.

We have searched the literature for data on the in vitro assessment of immune status in atopic eczema patients, and have found much confusion. The major findings are tabulated. It is concluded that atopic eczema is a form of immune deficiency, although it is unclear whether this is a primary or secondary defect. Most authors find a T-lymphocyte deficit while eosinophils, B lymphocytes and serum IgE are increased. Serum IgE levels appear to correlated with severity of eczema symptoms. We have previously suggested that T-lymphocyte levels are overestimated in eczema when fetal calf serum is used in the E-rosette assay. Analysis of the literature for the effect of this serum in the assay confirms that there is a T-lymphocyte deficit in atopic eczema, but that the serum masks it. Thus, much of the confusion surrounding this issue can be resolved.

Thymosin-inducible 'null' cells in atopic eczema.

Thirty children with atopic eczema were compared with an equal number of age-matched healthy children. The mean peripheral blood T-lymphocyte level was lower in the eczema group (mean 1,197/mm2 as against 1,702/mm3; P = 0 . 003). This difference was abolished in vitro by thymosin, a thymic hormone extract. Positive correlations were found between eczema severity and: eosinophilia; hyperimmunoglobulinaemia E; but not T lymphopaenia. Thymosin-inducible T-cell (Ti) counts correlated with plasma IgE levels, suggesting that these Ti cells may be immature suppressor T cells. If this T-cell deficiency represents inadequate suppression of IgE responses, then a trial of treatment with thymosin appears to be warranted.

The effect of zygosity on the birth weight of twins in Aberdeen and northeast Scotland.

Birth weight data for 356 pairs of newborn twins of known zygosity and placentation are presented. The combined weights of dizygotic twins are heavier than those of monozygotic twins. The significance of this finding is discussed in relation to the association between increased maternal height and dizygotic twinning.

Thymosin-inducible lymphocytes in the peripheral blood of patients with malignant melanoma.

E rosette-forming (T) lymphocytes and surface immunoglobulin-bearing lymphocytes were estimated in 85 patients with malignant melanoma. The melanoma patient group had lower mean levels of T lymphocytes and higher mean levels of immunoglobulin-bearing (? B) lymphocytes than did normal subjects. The absolute and percentage depressions of T-cell levels in the melanoma patients were stage-related, as was the depression of total lymphocyte and B-lymphocyte levels. The T lymphopenia in the melanoma patients could, in vitro, be partially abolished by fetal calf serum (as used in many E rosetting methods), and could be totally abolished by thymosin fraction 5 (Hoffmann-La Roche) at optimum concentration. In view of the ability of thymosin to restore T cells to normal levels in all of the T-lymphopenic patients, a clinical trial of this hormone in selected melanoma patients of all stages appears to be warranted.

Familial lichen planus. Another disease or a distinct people?

When lichen planus strikes families, a very rare happening, it is likely to afflict younger members, to erupt more acutely, extensively, and gravely, attacking also nails and mucous membranes, and to recur. Ten patients with familial lichen planus, two each from five distinct Caucasian families, the parents of whom were unrelated by birth, were found to be carrying HLA-B7 statistically more frequently than in the normal population or in those with the characteristic forms of lichen planus. We hint that their genotype might have rendered them susceptible to a pathogen that precipitated their disease.

T-cell depletion and in vitro thymosin inducibility in asthmatic children.

Thirty asthmatic children were compared with an equal number of age-matched healthy children. The mean peripheral blood T-lymphocyte level without foetal calf serum was lower in the asthmatic group (mean 970/mm3, as against 1740/mm3; P less than 0.0001), but this difference was abolished by adding foetal calf serum or thymosin, thus explaining how quite severe T-cell deficiency can be missed by widely used methods. The degree of eosinophilia and the degree of elevation of the plasma IgE level in the asthmatic patients were positively correlated. Positive correlations were also shown between the degree of severity of the asthma, the degree of eosinophilia and the degree of elevation of the plasma IgE level, but not the degree of depression of the T-cell numbers. If this T-cell deficiency reflects an inadequate suppression of IgE responses, a clinical trial of thymosin appears to be warranted.

Analysis of hydrogen fluoride infrared chemiluminescence from simple atom-molecule reactions.

The various gas-phase atom-molecule reactions which have been shown to give hydrogen fluoride infrared chemiluminescence are reviewed and the wide range of information made available by high resolution spectroscopic studies is discussed.