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INTRODUCTION Radiobiological-based optimization functions for radiotherapy treatment planning involve dose-volume effects that could allow greater versatility when shaping dose distributions and DVHs than traditional dose volume (DV) criteria. Two of the most commercially available TPS (Monaco and Eclipse) already offer biological-based optimization functions, but they are not routinely used by most planners in clinical practice. Insight into the benefits of using EUD, TCP/NTCP-based cost functions in Monaco and Eclipse TPS was gained by comparing biological-based optimizations and physical-based optimizations for prostate and head and neck cases. METHODS Three prostate and three H&N cases were retrospectively optimized in Monaco and Eclipse TPS, using radiobiological-based cost functions vs DV-based cost functions. Plan comparison involved ICRU Report 83 parameters D95%, D50%, D2% and TCP for the PTV, and NTCP and RTOG tolerance doses for OARs. RESULTS Although there were differences between Monaco and Eclipse plans due to their dissimilar optimization and dose calculation algorithms as well as optimization functions, both TPS showed that radiobiological-based criteria allow versatile tailoring of the DVH with variation of only one parameter and at most two cost functions, in contrast to the use of three to four DV-based criteria to reach a similar result. CONCLUSION Despite the use of a small sample, optimization of three prostate and three head and neck cases allowed the exploration of optimization possibilities offered by two of the most commercially available TPS on two anatomically dissimilar regions. Radiobiological-based optimization efficiently drives dose distributions and DVH shaping for OARs without sacrifice of PTV coverage. Use of EUD-based cost functions should be encouraged in addition to DV cost functions to obtain the best possible plan in daily clinical practice

INTRODUCCION Las funciones de optimización basadas en radiobiología para la planificación del tratamiento de radioterapia implican efectos dosis volumen que podrían permitir una mayor versatilidad a la hora de dar forma a las distribuciones de dosis y DVH que los tradicionales criterios dosis-volumen (DV). Dos de los TPS más disponibles comercialmente (Mónaco y Eclipse) ya ofrecen productos de funciones de optimización de base biológica, pero la mayoría de los planificadores no las utilizan de forma rutinaria en la práctica clínica. El conocimiento de los beneficios del uso de las funciones de costos basadas en EUD, TCP/NTCP en Mónaco y Eclipse TPS se obtuvo comparando optimizaciones de base biológica y optimizaciones físicas para casos de próstata y cabeza y cuello. MÉTODOS Tres próstatas y tres casos de H&N en Mónaco y Eclipse TPS fueron optimizadas retrospectivamente usando funciones de costos basadas en radiobiología vs funciones de costos basadas en DV. La comparación de planes involucró los parámetros del Informe ICRU 83 D95%, D50%, D2% y TCP para el PTV, y dosis de tolerancia NTCP y RTOG para OAR. Resultados. Aunque hubo diferencias entre los planes Mónaco y Eclipse, debido a sus diferentes algoritmos de optimización y cálculo de dosis, así como funciones de optimización, ambos TPS demostraron que el criterio basado en radiobiología permiten una adaptación versátil del DVH con variación de un solo parámetro y como máximo dos funciones de costos, en contraste con el uso de tres o cuatro criterios basados en DV para alcanzar un resultado similar. CONCLUSIÓN A pesar del uso de una muestra pequeña, la optimización de tres casos de próstata y tres de cabeza y cuello permitió la exploración de las posibilidades de optimización que ofrecen dos de los TPS más disponibles comercialmente en dos regiones anatómicamente diferentes. La optimización basada en radiobiología impulsa de manera eficiente las distribuciones de dosis y la configuración de DVH para OAR sin sacrificar Cobertura de PTV. Se debe fomentar el uso de funciones de costos basadas en EUD además de las funciones de costos DV para obtener el mejor posible plan en la práctica clínica diaria

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For activated sludge modeling purposes, the methods used to evaluate the readily biodegradable chemical oxygen demand (RBCOD) in the influents are by biological or via physicochemical assays. However, there has not been sufficient wide comparison between these methods. The main goal of this study was to investigate the performance of the main chemical oxygen demand (COD) fractionation protocols, considering a representative wastewater in the context of tropical and developing countries. Different physicochemical characterization procedures, respirometric tests, and chemical analyses were performed. The fate of the soluble COD in the aeration tanks was studied. The results of the study showed that a marked difference may exist, in municipal wastewaters, between the estimates of the RBCOD fractions measured by respirometry and by any of the physicochemical methods. The evaluated influent showed a rather large fraction of COD that was passing the filters without being rapidly biodegradable, but which was removed quickly by enmeshment in the bioflocs. The consequences of such divergences and behavior are discussed.

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As part of the efforts done to introduce the practice of modeling in Latin America, this research carried out at the North-East WWTP of Monterrey represents the first comprehensive modeling case in Mexico. The main objective was to reproduce the organic carbon removal and sludge production rates of the plant, based on ASM1. Different intermediate studies were performed prior to the calibration of the model: influent characterization, tracer tests and hydraulics modeling, sludge settling tests and respirometry. Two fractionation methods (STOWA protocol and Influent-advisor) were compared, showing no equivalent patterns. A stepwise sequence of calibration was developed and successfully applied. The hydraulics of the reactors at the plant was reproduced by use of a series of 3 to 5 CSTRs. The waste and return activated sludge flowrates (Q(WAS) and Q(RAS)) were corrected based on the inorganic and total suspended solids mass balances. The Vesilind settling constants were measured (V(o) and r(hind)), while the flocculent zone settling parameter (r(floc)) was adjusted to calibrate the secondary clarifier. In ASM1, the adjusted parameters were the COD soluble inert fraction (frS(I)) and the particulate substrate fraction (FrX(S)). All other ASM1 parameters were kept at their default values. The steady-state calibrated model (in GPS-X) adequately described the quality of the effluent (carbon and nitrogen) as well as the sludge composition (M. Liquor and WAS). This case study provides voluntarily detailed data to allow its wide use for training and teaching purposes.

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The setup of the hydraulic model structure of wastewater treatment plants (WWTPs) is an important step in the calibration of activated sludge models. The hydrodynamics of a full-scale municipal WWTP (Monterrey, Mexico) has been studied by means of the use of tracer tests and of a commercial simulator. A presimulation approach allowed the authors to quantify the appropriate rhodamine mass, set up a sampling plan, and evaluate the anticipated visual effect of the tracer test in the receiving river. The hydraulic behavior of the aeration tank for the first treatment line, a 7-cell plug-flow reactor, was shown to be best represented by 5 virtual mixed-tanks-in-series. The second treatment line, which included a vertical loop reactor (VLR), was best modeled as 3 tanks-in-series. The VLR, alone, was shown to be similar to a continuously stirred tank reactor, and not a circuit of tanks, as generally used to represent oxidation ditch reactors.

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PURPOSE: To compare percutaneous coronary intervention (PCI) using stent implantation versus coronary artery bypass graft (CABG) in patients with multiple vessel disease with involvement of the proximal left anterior descending coronary artery (LAD). METHODS: 230 patients with multiple vessel disease and severe stenosis of the proximal LAD (113 with PCI, 117 with CABG). They were a cohort of patients from the randomised ERACI (Argentine randomized trial of percutaneous transluminal coronary angioplasty versus coronary artery bypass surgery in multivessel disease) II study. RESULTS: Both groups had similar baseline characteristics. There were no significant differences in 30 day major adverse cardiac events (death, myocardial infarction, stroke, and repeat procedures) between the strategies (PCI 2.7% v CABG 7.6%, p = 0.18). There were no significant differences in survival (PCI 96.4% v CABG 95%, p = 0.98) and survival with freedom from myocardial infarction (PCI 92% v CABG 89%, p = 0.94) at 41.5 (6) months' follow up. However, freedom from new revascularisation procedures (CABG 96.6% v PCI 73%, p = 0.0002) and frequency of angina (CABG 9.4% v PCI 22%, p = 0.025) were superior in the CABG group. CONCLUSION: Patients with multivessel disease and significant disease of the proximal LAD randomly assigned in the ERACI II trial to PCI or CABG had similar survival and survival with freedom from myocardial infarction at long term follow up. Repeat revascularisation procedures were higher in the PCI group.

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OBJECTIVE: The purpose of this study was to compare percutaneous transluminal coronary revascularization (PTCR) employing stent implantation to conventional coronary artery bypass graft surgery (CABG) in symptomatic patients with multivessel coronary artery disease. BACKGROUND: Previous randomized studies comparing balloon angioplasty versus CABG have demonstrated equivalent safety results. However, CABG was associated with significantly fewer repeat revascularization procedures. METHODS: A total of 2,759 patients with coronary artery disease were screened at seven clinical sites, and 450 patients were randomly assigned to undergo either PTCR (225 patients) or CABG (225 patients). Only patients with multivessel disease and indication for revascularization were enrolled. RESULTS: Both groups had similar clinical demographics: unstable angina in 92%; 38% were older than 65 years, and 23% had a history of peripheral vascular disease. During the first 30 days, PTCR patients had lower major adverse events (death, myocardial infarction, repeat revascularization procedures and stroke) compared with CABG patients (3.6% vs. 12.3%, p = 0.002). Death occurred in 0.9% of PTCR patients versus 5.7% in CABG patients, p < 0.013, and Q myocardial infarction (MI) occurred in 0.9% PTCR versus 5.7% of CABG patients, p < 0.013. At follow-up (mean 18.5 +/- 6.4 months), survival was 96.9% in PTCR versus 92.5% in CABG, p < 0.017. Freedom from MI was also better in PTCR compared to CABG patients (97.7% vs. 93.4%, p < 0.017). Requirements for new revascularization procedures were higher in PTCR than in CABG patients (16.8% vs. 4.8%, p < 0.002). CONCLUSIONS: In this selected high-risk group of patients with multivessel disease, PTCR with stent implantation showed better survival and freedom from MI than did conventional surgery. Repeat revascularization procedures were higher in the PTCR group.

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This paper reports findings from a screening study conducted to examine potential lead (Pb) exposures in residents of a Mexican village where Pb oxide continues to be used in ceramic pottery production. Extremely high Pb concentrations were measured in personal and indoor air samples, household surface dust samples, and household soil samples. Personal air Pb concentrations for workers performing pottery firing and glazing were up to 454 microg/m3. Results from indoor air samples indicate that airborne Pb concentrations were lower during nonglazing period compared to the glazing period. Soil Pb concentrations measured in 17 homes ranged from 0.39 to 19.8 mg/g. Dust Pb loading on surfaces of household items, hands, and clothes of a worker ranged from 172 to 33,060 microg/ft2. Pb content as high as 2.4 microg/g was found in a bean stew cooked in a pot made in the village. Based on these Pb concentrations measured in multiple media and data adapted for exposure contact rates, we have made rough estimates of Pb exposures via inhalation, soil/dust ingestion, and food ingestion. Estimated total daily Pb intake, on average, is 4.0 mg for adults and 3.4 mg for children living in the village. In the total daily intake, a greatest fraction may be contributed by food ingestion and another significant fraction may come from soil/dust ingestion for the children. Although the sample size is small, these measurements indicate a very significant public health problem for the village residents and a large number of other similar communities in Mexico. (It was estimated that there are approximately 1.5 million glaze potters.) The Pb exposure is implicated in a number of pervasive health problems in the region, and is the cause for national and international attention. Several recommended solutions to this problem range from personal protection and behavioral changes to introduction of alternative glazes.

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We present a new method of myocardial revascularization. The radial artery is used in combination with the left internal mammary artery, thereby providing three distal end-to-side anastomoses to the left anterior descending coronary artery and other sites as determined by the coronary artery lesions. Arterial conduits form an anastomotic network between the left internal mammary artery and the radial artery in a horseshoe pattern. Three coronary arteries are revascularized by two arterial conduits in the left coronary system.

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The Stentless USL, Unique Suture Line porcine valve, is a stentless bioprosthesis developed following the advantages of the studies of the physiology of the aortic root as a functional unit. The direct suturing of the porcine tissue on the soft and elastic tissue of the host's aortic annulus and root gives the bioprosthesis the possibility to follow the physiological movements of the natural valve during the cardiac cycle. For the same reason, there is decreased stress on the valve tissue, especially at the commissural level. There is less technical demand for surgeons who have limited experience with the freehand or miniroot technique due to the limited availability of the homografts because the Stentless USL valve can be implanted with the same technique used with a conventional stented valve. The implant technique used for the Stentless USL valve has advantages, especially in the small aortic calcified annulus in elderly patients where the freehand technique can be difficult and the second suture line can be dangerous (i.e., coronary ostium near the aortic ring or in calcified aortic wall). Our experience with this stentless valve in approximately 200 patients (> 70 years old) shows it to have excellent hemodynamic results even in small valve sizes. The use of this valve and the simple implantation technique avoids the need for complicated aortic root enlargement procedures.

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A prospective, four-year longitudinal study of 209 Peruvian children was conducted to evaluate the effect of a single malnutrition episode occurring at infancy (i.e., < 1 year of age) on dental caries in the primary teeth. Children were recruited into the study at age 6-11 months after they had suffered from a malnutrition episode and were thus classified by anthropometry as either: (1) Normal; (2) Wasted (low weight for height); (3) Stunted (low height for age); or (4) Stunted and Wasted (S and W). Eruption of the primary teeth was significantly delayed in all malnourished children; however, the effect of stunting--that is, retarded linear growth--was more pronounced and lasted longer than that of wasting or acute malnutrition (i.e., 2.5 vs. 1.5 years, respectively). By age 4 years, children from group 4 (S and W) showed a significantly higher caries experience in the primary teeth than did those in any of the other three groups. In summary, this longitudinal study has confirmed previous studies in animals and indirect epidemiological evidence which had suggested a cause-effect relationship between early malnutrition and increased dental caries.

PIP: The study was conducted from 1986 through 1990 among 209 children residing in Canto Grande, a poor community located north of Lima, Peru. The children were recruited as infants, aged 6-11 months, from the outpatient population of the Canto Grande Health Center, or from two other hospitals. All children were of full-term gestation and normal birth weight ( 2500 g). Each child was assigned to 1 of 4 study groups ascertained by weight and height measurements, with the National Center for Health Statistics standards used as the reference: 1) normal; 2) wasted, indicating current acute malnutrition; 3) stunted, indicating past or chronic malnutrition; and 4) stunted and wasted, indicating malnutrition soon after birth. The data, composed of 2700 examinations, were analyzed by the Statistical Analysis System (SAS) General Linear Models (GLM) program for computation of ANOVA tables. The mean numbers of teeth at ages 1 and 1.5 years for normal children were significantly higher than those of the children who were either wasted, stunted, or stunted and wasted as infants. At age 2, normal children had significantly more teeth in the mouth than did stunted children and stunted and wasted children. At age 2.5, the number of teeth in the normal children was still significantly higher than in stunted children. At age 4, all 4 groups had their full 20 teeth. At age 4, children who were stunted and wasted during infancy showed a significantly higher number of decayed, extracted, and filled teeth (def) compared with that of the other 3 groups. When grouped into 4 def categories of low, moderate, high, and very high caries experience, the distribution of the 4th group was distinctly different from that of the other 3 groups. 17.2% of stunted and wasted children had a very high caries experience (i.e., def 13) at age 4, significantly higher than that in any of the other 3 groups (i.e., normal 9.8%, wasted 4.4%, and stunted 3.6%, respectively; p 0.001).

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A cross-sectional study of dental caries in the primary teeth as a function of nutritional status was conducted on 1481 children one to 13 years old in Lima, Perú. Forty-one percent of the children were found to be chronically malnourished (stunted), 3% were acutely malnourished (wasted), and 5% were both stunted and wasted. A plot of decayed, extracted, and filled teeth (deft) vs. age resulted in a bell-shaped curve that was shifted to the right by 2.5 years for malnourished groups, compared with normal children (p less than 0.01). The shift to the right of the age distribution of caries was associated with a delay in both the eruption and exfoliation of the primary teeth in malnourished children. Peak caries activity was significantly higher in wasted and in stunted and wasted children, when compared with normal controls. It is concluded that malnutrition delayed tooth development, affected the age distribution of dental caries, and resulted in increased caries experience in the primary teeth.

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This study was designed to evaluate the relationship between anthropometric indicators of malnutrition and tooth eruption status of 6-year-old children. The 100 subjects from the Kingston area were placed into groups, as per Waterlow's classification of protein-energy malnutrition (PEM), according to height-for-age (H/A) and weight-for-height (W/H) and number of emerged teeth noted (table included). Statistical analysis (ANOVA - Duncan's test) indicates a significant decrease (p<0.01) in the number of erupted permanent teeth emerged in the Stunted and the Stunted Wasted (p<0.05) as compared to the Normal children (AU)

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A cross-sectional evaluation of dental caries in primary teeth and nutritional status was conducted involving 285 Peruvian children from low socioeconomic conditions aged 3-9 y. Forty-nine percent of the children were found to be chronically malnourished (stunted) whereas acute malnutrition (wasting) was infrequent (2%). Stunted children showed a delayed exfoliation of primary teeth. The caries prevalence curve as a function of age (ie, a plot of decayed, extracted, and filled teeth vs age) was found to be shifted to the right by approximately 15 mo in stunted children as compared with well-nourished children. Children aged 7-9 y with stunted growth showed a significantly higher percentage of carious teeth than did well-nourished children of the same age (40 and 29%, respectively; p less than 0.005). Nutritional deficits that lead to chronic malnutrition not only may affect tooth exfoliation but also appear to render the primary teeth more susceptible to caries attack later in life.

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Elective treatment of descending thoracic aneurysms involves direct surgery, with Dacron graft replacement of the diseased aortic segment. When the patient's condition contraindicates major surgery, however, the surgeon should consider using an extraanatomic approach-implanting an ascending aorta-to-abdominal aorta Dacron bypass graft in a ventral position and leaving the diseased segment undisturbed. After such a procedure, the descending thoracic aorta must be excluded from the normal circulation. For this purpose, we have designed an intraaortic occluding technique in which an umbrella-like device is implanted immediately distal to the left subclavian artery. This technique has proved safe and uncomplicated in canine experiments and is ready for clinical trials.

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A method for supporting the porcine valve was devised to approximate more closely the normal porcine anatomy. This mounting technique resulted in a low profile valve with a greater valve orifice and a lower transvalvular gradient than other porcine bioprostheses (Liotta BioImplant L.P.B., BioImplant, Canada, Inc). There were 297 valves implanted in 279 patients operated on from November 1978 through December 1981. Of these, there were 132 aortic valve replacements (AVR), 129 mitral valve replacements (MVR), and 18 double valve replacements (DVR). The actuarial curve at 72 months showed a late patient survival of 78.48% +/- 5.68% for AVR, 86.27% +/- 4.3% for MVR, and 77.78% +/- 12.2% for DVR. Of these, 93.6% of the AVR patients and 81% of the MVR patients remained in the New York Heart Association Class I postoperatively.

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This report summarizes results of the first 453 consecutive patients who had 491 low profile bioprostheses implanted at the Italian Hospital in Buenos Aires over a 5-year period. During this time, with the goal of long-term durability, the valve mounting technique was slightly modified, whereas the materials and design of the annulus underwent more extensive changes.

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