Extreme ocean acidification reduces the susceptibility of eastern oyster shells to a polydorid parasite.

Ocean acidification poses a threat to marine organisms. While the physiological and behavioural effects of ocean acidification have received much attention, the effects of acidification on the susceptibility of farmed shellfish to parasitic infections are poorly understood. Here we describe the effects of moderate (pH 7.5) and extreme (pH 7.0) ocean acidification on the susceptibility of Crassostrea virginica shells to infection by a parasitic polydorid, Polydora websteri. Under laboratory conditions, shells were exposed to three pH treatments (7.0, 7.5 and 8.0) for 3- and 5-week periods. Treated shells were subsequently transferred to an oyster aquaculture site (which had recently reported an outbreak of P. websteri) for 50 days to test for effects of pH and exposure time on P. websteri recruitment to oyster shells. Results indicated that pH and exposure time did not affect the length, width or weight of the shells. Interestingly, P. websteri counts were significantly lower under extreme (pH 7.0; ~50% reduction), but not moderate (pH 7.5; ~20% reduction) acidification levels; exposure time had no effect. This study suggests that extreme levels - but not current and projected near-future levels - of acidification (∆pH ~1 unit) can reduce the susceptibility of eastern oyster shells to P. websteri infections.

The inverse problem of electrocardiography: a solution in terms of single- and double-layer sources of the epicardial surface.

An approach to the inverse problem of electrocardiography that involves an estimation of the electric potentials (double-layer equivalent sources) on the heart's epicardial surface from the electrocardiographic potentials that are measurable on the body surface has received considerable attention. This report deals with a heretofore unexplored extension of this approach, one that yields, in addition to the electric potentials on the epicardial surface, the normal components of their gradients (single-layer equivalent sources). We show that this formulation has at least three advantages over the formulation in term of epicardial potentials alone: (1) single-layer equivalent sources, which reflect the flow of current across the epicardial surface, are well suited for the imaging of regional ischemia and infarction; (2) the transfer matrix linking the epicardial and body-surface potentials for this formulation is less ill conditioned than that for the formulation in terms of potentials alone; (3) the input vector for inverse calculations consists of spatially filtered (rather that directly measured and therefore noise) body-surface potentials. To establish the feasibility of this new formulation of the inverse problem and to compare it with the formulation in terms of potentials alone, we used a realistically shaped boundary-element model of human torso. By calculating singular values less ill conditioned. We then directly calculated epicardial and body-surface potentials for a single dipole located centrally and for three simultaneously active dipoles located eccentrically in the torso's heart region and used these results to test three methods that are prerequisites of a successful inverse solution: Tikhonov regularization, linearly constrained least squares, and an L-curve method. The feasibility of the new formulation was demonstrated by the fact that the method based on the linearly constrained least squares improved on overregularized Tikhonov solutions over a wide range of regularization parameters, and it yielded solutions that were more accurate than the best-possible Tikhonov solutions. Moreover, the L-curve solution procedure, which requires no a priori information about the solution, yielded slightly underregularized, but accurate, estimates for the optimal regularization parameter and the corresponding best-possible Tikhonov solution. Our results also showed that replacing--in the interest computational economy--quadrature formulas for the planar triangles with various approximate formulas for the nodes of the model reduces the accuracy of the inverse solution.

Transperineal ultrasound-guided radioactive seed implantation for organ-confined carcinoma of the prostate.

PURPOSE: This retrospective study was undertaken to: (a) determine the prognostic significance of pretreatment and 1-year nadir serum prostate specific antigen (PSA) levels in organ-confined carcinoma of the prostate treated with ultrasound-guided radioactive 125I seed implantation; (b) determine the factors associated with postimplant morbidity and whether modification of the technique would reduce morbidity; (c) evaluate the local control rate and disease-free survival of patients undergoing seed implantation. METHODS AND MATERIALS: From October 1988 through December 1992, 142 patients with organ-confined adenocarcinoma of the prostate and a Gleason score < or = 7 underwent ultrasound-guided radioactive 125I seed implantation as an alternative to radical prostatectomy. Patients were considered to have persistent or progressive disease if there was evidence of local progression on digital exam, or if there were two consecutive increases in the PSA level. Patients suspected of persistent or progressive disease underwent restaging to include CT scan of the pelvis, bone scan, and ultrasound-guided prostate biopsy. Patients with increasing PSA levels in which active disease could not be confirmed were considered biochemical failures with occult systemic disease and were offered hormone ablation. RESULTS: With 1-6-year follow-up, median 30 months, the relapse patterns were prostate 4 (2.8%), bone 4 (2.8%), rising PSA 16 (11%). Pretreatment PSA level correlated with subsequent recurrence; pretreatment PSA < or = 4 (0), 4.1 to 10 (14%), 10.1 to 20 (21%), 20.1 to 50 (58%). Disease free survival at 2 years was 90% and at 5 years 76%. Nadir PSA (nPSA) at 1 year also correlated with recurrence: nPSA < or = 1 (3%), nPSA 1 < or = 4 (50%), and nPSA > or = 4 (100%). Seed implantation was well tolerated with 31% of patients experiencing RTOG morbidity > or = Grade 2, which typically consisted of transient radiation urethritis, which resolved with conservative measures. Eleven (8%) experienced RTOG morbidity > or = Grade 3. There was no correlation between number of seeds or total millicuries implanted and subsequent morbidity. However, reduction in the periurethral seed intensity reduced > or = Grade 3 morbidity from 11 to 4%. CONCLUSION: Ultrasound-guided radioactive seed implantation provides excellent local control of 97%, with a median 30 month follow-up. Morbidity is comparable to other curative modalities and by modifying Blasko's technique to reduce radioactive seed strength in the periurethral area, significant morbidity is rare. Pretreatment PSA and the nadir PSA at 1 year are important predictors of subsequent disease outcome. With a liberal definition of systemic recurrence as two consecutive increases in PSA levels, the 5-year disease-free survival is 76%.

A brief correction procedure for the management of high rate spitting in a profoundly retarded girl.

This study demonstrates the effectiveness of a brief correction procedure in decelerating a high rate anti-social behaviour (spitting) in a profoundly retarded girl. A simple correction procedure seemed as effective as a more elaborate procedure incorporating positive practice elements, and gains were sustained with some variability over an extended period of time. No reliable increases in collateral behaviours were noted to result from the deceleration in spitting.

A preliminary investigation on the use of the Portage system in day nursery settings.

The paper describes the impact of a training programme for local authority day nursery staff on the use of the Portage system with handicapped children. The results suggest that the staff mastered the techniques and were able to continue using them, though some modification to the system seems indicated for these settings. These findings were discussed in the light of more general issues about the support needed for day nursery staff.

Radiation therapy for nonseminomatous germ cell tumors of the testis: a reappraisal.

We analyzed the efficacy of radiation therapy and retroperitoneal lymphadenectomy preceded and followed by radiation therapy as curative treatment in 113 patients with clinical stages I and II nonseminomatous germ cell tumors of the testis. Radiation therapy alone was curative in 86 and 82 per cent of the patients with clinical stages I and II disease, respectively, and radiation therapy before and after retroperitoneal lymphadenectomy was curative in 89 and 73 per cent of patients with clinical stages I and II disease, respectively. Of 26 patients with clinical stage II disease in the group receiving radiation therapy before and after retroperitoneal lymphadenectomy only 13 (50 per cent) had pathologic documentation of retroperitoneal metastasis or histologic evidence of nodal metastases that had been destroyed by radiation therapy alone. When analyzed by pathologic stage radiation therapy before and after retroperitoneal lymphadenectomy was curative in 91 and 51 per cent of patients with stage I and II disease, respectively. In our series clinical overstaging may have been responsible for the favorable results of radiation therapy alone, and radiation before and after retroperitoneal lymphadenectomy in the treatment of clinical stage II nonseminomatous germ cell tumors.

Prostatic trauma and release of acid phosphatase. Radioimmunochemical and enzymatic comparison.

Radioimmunoassay for prostatic acid phosphatase and a conventional enzymatic method using alpha-naphthyl phosphate were employed to document the changes in serum levels of this enzyme following transurethral prostatectomy and prostatic massage. Thirty-four patients with histologically proved benign prostatic hyperplasia and 120 controls were studied. Consistent parallel elevations were noted after surgical trauma. A rapid clearance was observed with normal levels returning at twenty-four hours. Prostatic massage did not elicit a change by either method.

A home advisory service for pre-school children with developmental delays.

This paper describes the development of a home advisory service for families of children with developmental difficulties. It demonstrates the transition from a research phase to routine service provision, and indicates that the expansion in numbers of families receiving the service has been achieved whilst maintaining or improving the actual quality of the service. Information is provided on the placement of children who have left the service, and on the plans for future research within the service.

Anaplastic seminoma: an analysis of 77 patients.

Over a 28 year period, 77 patients with early stage anaplastic seminoma of the testis were treated by orchiectomy and lymphatic irradiation at three Army medical centers. With a median follow-up of 97 months, the 10 year actuarial survival is 96% of Stage I patients and 87% for Stage II patients. For patients with Stage I anaplastic seminoma no survival advantage can be demonstrated for adding mediastinal and supraclavicular irradiation versus para-aortic and pelvic irradiation alone. The addition of retroperitoneal lymphadenectomy to lymphatic irradiation increased the frequency of major gastrointestinal complications without significantly improving survival. Patients with anaplastic seminoma and elevated serum beta-subunit human chorionic gonadotrophin levels have a poor prognosis and should be considered for adjuvant combination chemotherapy. Anaplastic seminoma of the testis has a similar clinical presentation, response to therapy and prognosis compared to typical seminoma and should be managed in the same way.

Clinical evaluation of the Technico Stat/Ion system.

1. We describe our evaluation of the Technicon Stat/Ion, an instrument which performs sodium, chloride and bicarbonate analysis simultaneously. 2. All four of the assays resulted in linear response over the entire clinical range with insignificant carryover between specimens. 3. Precision studies for within-run variation were: sodium 0.3 percent, potassium 0.7 percent, chloride 0.5 percent and bicarbonate 1.6 percent. Day-to-day precision was similar to the within-run precision. 4. Comparison methods for sodium, potassium, chloride and bicarbonate utilizing flame photometry, chloridometry and titration of released carbon dioxide respectively showed the following linear regression and correlation coefficients: sodium y=0.96+5.5 (a=0.988) potassium y=1.01x+0.0 (a=.996) chloride y=0.99x+1.0 (a=.993)bicarbonate y=1.0x+1.2 (alpha=.969).