Application of influence diagrams to prostate intensity-modulated radiation therapy plan selection

The purpose is to incorporate clinically relevant factors such as patient-specific and dosimetric information as well as data from clinical trials in the decision-making process for the selection of prostate intensity-modulated radiation therapy (IMRT) plans. The approach is to incorporate the decision theoretic concept of an influence diagram into the solution of the multiobjective optimization inverse planning problem. A set of candidate IMRT plans was obtained by varying the importance factors for the planning target volume (PTV) and the organ-at-risk (OAR) in combination with simulated annealing to explore a large part of the solution space. The Pareto set for the PTV and OAR was analysed to demonstrate how the selection of the weighting factors influenced which part of the solution space was explored. An influence diagram based on a Bayesian network with 18 nodes was designed to model the decision process for plan selection. The model possessed nodes for clinical laboratory results, tumour grading, staging information, patient-specific information, dosimetric information, complications and survival statistics from clinical studies. A utility node was utilized for the decision-making process. The influence diagram successfully ranked the plans based on the available information. Sensitivity analyses were used to judge the reasonableness of the diagram and the results. In conclusion, influence diagrams lend themselves well to modelling the decision processes for IMRT plan selection. They provide an excellent means to incorporate the probabilistic nature of data and beliefs into one model. They also provide a means for introducing evidence-based medicine, in the form of results of clinical trials, into the decision-making process.     

Age-related reductions in rat atrial high affinity choline uptake, ACh synthesis, and ACh release. A brief note

We have developed a rat atrial mince preparation that can take up choline, acetylate it, and then release acetylcholine in a depolarization-dependent manner. We demonstrate that aging appears to reduce the functional cholinergic activity in this tissue, which may be important for understanding how senescence alters the regulation of cardiac activity.     

Impedance-gradient electrode reduces skin irritation induced by transthoracic defibrillation

A new type of disposable external defibrillation electrode has been developed to reduce the skin irritation commonly associated with defibrillation and synchronised cardioversion. This design employs an impedance gradient to reduce the proportion of current delivered to the electrode periphery. The temperature distribution under the new electrode was compared with that of four other types of commercially available electrodes after repeated high-energy biphasic defibrillation discharges to domestic swine. Skin temperature distributions were acquired using non-invasive thermography. Measurements of the maximum temperature rise at each electrode site, taken 3.6s after the fifth defibrillation discharge, demonstrated that the new impedance-gradient electrode produced 50–60% less skin heating than two of the three uniform-impedance electrode designs. Histological examination of erythematous sites excised 24h after defibrillation quantified the associated skin damage using a scoring protocol developed for this study. In contrast to previous studies, histological examinations demonstrated second-degree skin burns following defibrillation. The new electrode design, however, induced 44–46% less skin damage than two of the traditional uniform-impedance electrodes.     

Zur Induktion einer aktiven chronischen Hepatitis durch heterologe lösliche Leberproteine

Zusammenfassung Die Untersuchungen gehen von dem früher geführten Nachweis eines im immunologischen Sinne organspezifischen und weitgehend speciesexclusiven Proteins der Leber aus. Entsprechende Proteinpräparationen aus menschlichen Lebern wurden zur Sensibilisierung von Kaninchen eingesetzt.1. Bei langdauernder Sensibilisierung (über 1 Jahr) mit kleinen Dosen gelang beim erwachsenen Kaninchen die Induktion einer Immuntoleranz, die durch Applikation von hitzeund sulfanilsäurealteriertem Protein durchbrochen werden konnte; gleichzeitig konnte eine Hypersensibilität vom verzögerten Typ induziert werden. Histologisch fand sich bei allen Tieren eine aktive chronische Hepatitis; die übrigen Organe (Herz, Lunge, Skeletmuskulatur, Schilddrüse und Niere) waren frei von pathologischen Veränderungen.2. Bei kurzzeitiger Sensibilisierung (3 Monate) mit hohen Dosen fand sich histologisch lediglich eine dichtzellige lymphocytäre Infiltration der Periportalfelder der Leber; nur bei einem Tier bestanden geringe Hinweiszeichen auf eine beginnende chronische Lebererkrankung.In der Diskussion wird auf die serologisch nachweisbare Antigenverwandtschaft der entsprechenden Proteine von humaner und Kaninchenleber hingewiesen. Für die Entwicklung einer chronisch-progredienten Organerkrankung scheint die Ausbildung einer Hypersensitivität vom verzögerten Typ im Rahmen einer langdauernden Stimulierung wesentlich zu sein.

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Induction of chronic active hepatitis by organspecific heterologic soluble proteins of the liver

Summary These investigations are concerned with species- and organspecific liver proteins, demonstrated in earlier studies. Rabbits were sensitized utilizing similar protein-preparations obtained from human liver.1. With long-term sensitizations (approximately one year) immuntolerances were induced in adult rabbits by chronic administration of small doses of protein. The state of immun tolerance could be disturbed by applying of heat- and sulfanilic acid-altered protein, which at the same time could be shown to have induced hypersensitivity of delayed type. — Histologically active chronic hepatitis was found in all animals. Other organs such as heart, lung, skeletal muscle, thyroid gland and kidney were not affected.2. In short-term sensitizations with a high dosis of liver protein only dense lymphocytic infiltrations in the periportal areas were found histologically. In one animal only early changes of a chronic hepatitis were seen.Antigenic relations between human and rabbit liver proteins, as demonstrated earlier by serological techniques, are discussed in detail. Hypersensitivity of the delayed type would seem to play an important role in the development of active chronic hepatitis. This condition can be produced with long-term stimulations.

     

Complex karyotypic abnormality in ovarian fibroma associated with Gorlin syndrome

Nevoid basal cell carcinoma (NBCC) syndrome is an autosomal dominant disorder characterized by distinctive congenital malformations and a variety of benign and malignant neoplasms, including ovarian fibromas. We describe pathologic and cytogenetic findings in a large unilateral ovarian fibroma from a 12-year-old female with NBCC syndrome. The pathologic findings were characteristic for ovarian fibroma, but were unusual for the ovarian fibromas associated with NBCC syndrome because of the absence of calcification, the lack of bilaterality, and the presence of focal hypercellularity. The karyotype of tumor tissue showed complex numerical and structural abnormalities. Although there is frequent loss of heterozygosity of 9q22.3 and mutations in the PTCHgene in Gorlin syndrome, the ovarian fibroma in this case did not have cytogenetically detectable abnormalities of chromosome 9.     

How a community-based organization and an academic health center are creating an effective partnership for training and service.

Community-academic partnerships in the training of doctors offer unique learning opportunities of great importance. Such partnerships can induce a paradigm shift such that physicians view community as a teaching resource and partner rather than as a passive recipient of services or solely as a placement site. The authors describe a model of a community-academic partnership in New York City, begun in 1995, in which, for training and service, pediatric residents are integrally involved in a community-based program. Principles adapted from the Community-Campus Partnerships for Health's principles of partnership provide a framework for portraying the essential elements of developing and maintaining the partnership. The authors explain the clashes that may arise between partners and show how the principles of partnership guide partnership members in working and learning within a setting that by its nature entails conflict and inequality. This report is based on the knowledge gained from the structured reflections of both members of this partnership: the residency program at a large academic health center and the community-based social service organization. Such partnerships provide the training ground for the development of physicians who understand the social and cultural determinants of health and constructively use community agencies' input in promoting child health and well-being. Within this framework, community-based organizations are not solely service providers but become educators of physicians-in-training who, with new knowledge gained through the partnership, more effectively contribute to the overall health of the communities they serve.     

Psychological factors associated with the uptake of measles immunization: findings and implications for prevention

A cross-sectional study of 8204 children was performed to investigate the prevalence of immunization against measles, mumps and rubella and possible determinants of immunization uptake. The study was approached from a Lewinian perspective on preventive behaviour. Seventy-one questions referring to the guardian of the child, his or her partner, the household and the child, as well as to immunization-related experiences and situational topics were asked. Two psychological variables were studied: health locus of control and subjective relevance concerning measles. The immunization rate was 77.7 percent [95 percent confidence interval 76.8-78.6]. Multiple logistic regression yielded the following odds ratios for non- uptake of measles immunization: natural health orientation 8.74 [6.72-11.37]; advice of paediatrician 6.02 [4.67-7.75]; dangerousness of measles 2.00 [1.53-2.60]; marital status 1.87 [1.31-2.51]; assessed reliability of vaccination 1.57 [1.23-2.01]; smoking 1.55 [1.21-1.98]; and number of siblings 1.55 [1.21- 1.98]. Parents or guardians of immunized children were more internal and assessed measles as more relevant than those of non- immunized children.     

Escherichia coli Isolated from Domestic Animals Pathogenic for Gnotobiotic Piglets

Three strains of Escherichia coli isolated from infectious processes in a calf, a dog, and a cat were examined for their capacity to produce disease or death, or both, in newborn gnotobiotic piglets. The O groups represented by these particular strains of E. coli were O4: (canine origin), O6: (feline origin), and O39: (bovine origin). All three isolates upon oral administration proved to be pathogenic. Infection with the E. coli O4: (canine) or O39: (bovine) consistently produced signs of enteric coli-bacillosis and death in all 1- and 3-day-old piglets within 24 to 48 hr. The O6: (feline) isolate, on the other hand, produced a marked polyserositis and generally required 6 to 7 days to kill a piglet. Only the respective type of E. coli used in the particular trial was recovered from the diseased piglets. These findings suggest the possible role of domestic animals and household pets in the spread of potentially pathogenic E. coli to other species.