Defining the sources of low-flow phosphorus transfers in complex catchments.

Nutrient transfers from the land to rivers have the potential to cause persistent eutrophic impacts at low flows even though the transfers may constitute a minor percentage of total annual fluxes. In rural catchments, the contribution from agricultural soils during storm events can be particularly large and untangling the relative contributions from multiple sources that vary in time and space is especially problematic. In this study, the potential for domestic septic tank system pollution during low flows was investigated in 3 small catchments (3 to 5 km(2)) using an integrated series of methods. These included septic system surveys, continuous (10 min) total phosphorus (TP) monitoring at the outlet of each catchment, repeated low-flow water quality surveys in sub-catchments upstream of the catchment outlets and single day river-walk water quality surveys. A series of faecal matter and grey-water fingerprinting techniques were also employed. These included determining sterol ratios in stream sediments, monitoring the presence of proteins, E. coli and enterococci bacterial signatures and boron. The total density and density of poorly maintained septic systems mirrored the magnitude of frequent TP concentrations in the catchments although this relationship was less apparent in the nested sub-catchments. The exception was possibly related to the simple hydraulics in one particular catchment and indicated temporary effluent attenuation in the other catchments. Repeated low-flow and river-walk water quality surveys highlighted discrete areas and reaches where stepped changes in nutrient concentration occurred. Bio-chemical fingerprinting showed that between 7% and 27% of sediments were contaminated with human faecal material and correlation matrices indicated that, at least during low flows, P fractions were positively correlated with some markers of faecal and grey-water contamination.

Analysis of malignancy detected by needle-localized breast biopsy.

The medical records of 192 women with nonpalpable mammographically detected breast lesions who underwent needle-localized breast biopsy between January 1989 and January 1991 and between March 1992 and March 1994 were reviewed. Of the 192 patients examined, 100 underwent biopsy for evaluation of microcalcifications suggestive of malignancy. Ninety-two biopsies were performed for non-specific radiodensities not inclusive of microcalcifications. This study examines the radiographic characteristics of the nonpalpable breast lesion. Although presence of microcalcifications on mammograms are an important finding in detection of breast carcinoma, it must not be considered pathognomonic. Other distinguishing factors require evaluation to assess the indication for biopsy. Central to this study was the presence of microcalcifications alone or as detected in association with a dominant mass. Cancer was discriminated in 38 (20%) of the patients studied. Mammographic findings with microcalcification, regardless of the presence of a mass, were found to be malignant in 20% of patients undergoing biopsy. Nine percent of biopsies done to evaluate microcalcifications alone were malignant. The finding of microcalcification associated with a dominant mass proved malignant in 34% of patients who had a biopsy done. The authors include guidelines for increasing the effectiveness of needle-localized biopsies of the breast.

Mitral Valve Prolapse in Young Patients.

In brief: From 1% to 5% of young individuals are found to have, on clinical or echocardiographic examination, a prolapsing mitral valve. The majority of these patients are asymptomatic, and require from the physician an explanation of this defect and reassurance that the condition usually remains mild. Beta-blocking drugs are prescribed for patients with disabling chest pain, dizziness, or palpitation, or if potentially serious rhythm disorders develop. Physicians caring for these young patients must manage each case individually and must remain mindful that the natural course studies come from a perspective of only 25 years.

Aortic thrombosis in the neonate.

The case histories of two infants with aortic thrombosis are presented. Clinically, an obstructive aortic arch lesion was suspected because of a systolic pressure gradient between the upper and lower extremities in one infant and unequal peripheral pulses with lower limb cyanosis in the other. Noninvasive studies were inconclusive, the only abnormality noted echocardiographically being severe left ventricular dysfunction. Cardiac catheterization including angiography defined the severity of the obstruction and location of the thrombus in both babies. The thrombus originated within a ductus arteriosus aneurysm in one infant and was located in the ascending aorta and transverse arch in the other. Although successful surgical removal was accomplished, both babies died unexpectedly in the early postoperative period.

Development of pulmonary arteriovenous shunt after superior vena cava-right pulmonary artery (Glenn) anastomosis. Report of four cases.

Four patients with cyanotic congenital heart disease who had previously undergone superior vena cava-right pulmonary artery (Glenn) anastomosis developed pulmonary arteriovenous malformations that resulted in significant intrapulmonary right-to-left shunting. This abnormality was documented by selective angiography, oximetry, and contrast echocardiogrphy. It may be a major cause of late clinical deterioration in patients treated with the Glenn anastomosis.

Ebstein's malformation. Surgical experience at the Mayo Clinic.

At the Mayo Clinic, 13 patients with Ebstein's malformation have undergone surgical repair since 1963. Their ages ranged from 18 months to 51 years (median 13 years). Ten patients were in Functional Class III or IV. Marked cardiomegaly, cyanosis, paradoxic emboli, and dysrhythmias secondary to Wolff-Parkinson-White syndrome were indications for operation in the remaining 3 patients. A wide range of anatomic variations was encountered. All 5 patients who underwent tricuspid annuloplasty with plication of the atrialized segment of the right ventricle survived operation. Of 5 patients who underwent prosthetic valve replacement, only one survived. Other procedures included atrial septal defect closure alone in one patient, atrial septal defect closure and relief of pulmonary stenosis in one patient, and tricuspid annuloplasty alone in one patient. One patient had concomitant mapping and division of anomalous conduction pathways. Functional classification improved in 8 of 10 operative survivors. There were two late sudden deaths; both patients had had preoperative dysrhythmias. The data suggest that results are improved when the atrialized segment of the right ventricle is dealt with during repair of the tricuspid valve. A combined ventricular plication and tricuspid annuloplasty yielded better early and late results than did valve replacement.

Truncus arteriosus and previous pulmonary arterial banding: clinical and hemodynamic assessment.

Twenty-seven patients with truncus arteriosus and previous pulmonary arterial banding were evaluated 1 1/2 to 14 years (mean 7 years) after banding. Ages at the time of cardiac catheterization ranged from 3 to 18 years (mean 9 years). Current symptoms were severe in five patients and were related to truncal valve incompetence or decreased pulmonary blood flow (or both) rather than to age, duration of palliation or band location. Twenty-one of 22 patients with two pulmonary arteries were considered to be in a hemodynamically operable state at the time of study. The condition of three of five patients with a single pulmonary artery was subsequently found inoperable because of severe pulmonary vascular disease in the lung supplied by the single pulmonary artery. In patients with two pulmonary arteries, demonstration of low pressure in at least one normal-sized pulmonary artery established operability. Postoperative pressure measurements correlated well with preoperative prediction of operability, with 19 of 20 patients having a pulmonary arterial pressure less than 70 percent of systemic levels after repair. Bilateral pulmonary arterial binding may be more effective than central arterial banding (which frequently produces severe obstruction to the right pulmonary artery) in preventing pulmonary vascular obstructive disease in patients with truncus arteriosus who have two pulmonary arteries. Patients with truncus arteriosus and a single pulmonary artery with pulmonary arterial banding remain at high risk for the development of pulmonary vascular obstructive disease.