Exploring the software development trilogy

Software development is concerned with more than just generation of code; the program must have the desired properties, and these must be demonstrated via suitable tests and correctness arguments. One way of viewing these aspects is to group them into programs, properties, and data. When represented as vertices in a triangle, the edges represent processes to produce one element from another. The research reported in this article aims at practical methods for automatic test generation by restricting the use of both predicate logic and programming constructs. It promises to eventually result in practical domain-specific programming languages, with a significant boost in both quality and productivity     

Intact pancreatic islet function despite humoral xenorecognition in the pig-to-monkey combination

BACKGROUND: The aim of this study was to analyze humoral xenoreactivity of various Old World primate species sera against pig islets and the effects of these sera on pig islet viability and function after culture. METHODS: Freshly isolated or cultured adult pig islets were analyzed by immunohistology or by cytofluorimetry for Old World primate xenoreactive natural antibody (XNA) binding and complement deposition. Complement-mediated cytotoxicity was evaluated by 51Cr release assays. After 4 days of culture in 50% sera from Old World primates, the morphology and in vitro metabolic function of pig islets were also analyzed. RESULTS: Chimpanzee, Macaca mulatta (rhesus), or baboon XNA binding was detectable only on intra-islet endothelial cells (ECs). Incubation of pig islets with sera from all Old World primate species tested showed C3 and C4 deposition on ECs and on some surrounding endocrine cells. However, membrane attack complex (MAC) showed a pattern of positivity similar to XNA binding, i.e., restricted to ECs only. No deposition of factor B was detected. Although complement cascade was activated, no cytotoxicity was observed after incubation of islets with chimpanzee serum, whereas between 10% and 35% 51Cr specific release was obtained with rhesus, baboon, or Macaca fascicularis sera. Despite this cytotoxic effect, purified pig islets showed a normal morphology and a well-preserved insulin release in response to an acute glucose stimulus, after prolonged culture with 50% serum obtained from all primate species considered. CONCLUSIONS: Despite the fact that pig beta-cell function was not affected by the serum of any of the primate species tested, some of them yielded significant lysis of islet cells, presumably as a result of a cytotoxic effect on intra-islet ECs. These data show that Old World primate sera from different species do not have equivalent effect on pig islets; these differences should be taken into account in preclinical trials of pig islet xenotransplantation.     

Medical-economic models of benign prostatic hypertrophy

This article is designed to explain the importance of medico-economic models for evaluation of the impact of treatments of benign prostatic hyperplasia. The authors illustrate this approach by comparing two hypotheses: transurethral resection of the prostate versus watchful waiting using a Markov type of model. This model is able to simulate the probability of development of events such as transurethral resection of the prostate, acute urinary retention over a 40-year period by 3-month cycles. The model is also able to simulate the mean cost of management of a patient over this period. This type of model may appear slightly artificial and complicated, but it is the only model which could allow long-term simulations of the respective value of the various therapeutic strategies for BPH. This type of model is also evolutive, its performance is gradually improved as new data become available in the literature, allowing refinement of a number of hypotheses.     

Vesicular transport: implications for cell polarity

In polarized cells intracellular sorting of plasma membrane proteins occurs to a large extent at the trans-Golgi network, giving rise to vesicles destined for distinct plasma membrane domains. This review discusses the several pathways, both direct and indirect, which lead to protein incorporation into the correct cell surface, as well as the mechanisms involved. Proteins contain signals which direct their incorporation into the distinct vesicles destined for plasma membrane microdomains. Specific coat proteins are involved in vesicle assembly and are likely to play a role in the generation of discrete vesicle populations. Molecules involved in vesicle docking and fusion may also add specificity to the targeting process.     

Streptococcus mitis cell walls and lipopolysaccharide induce lethality in D-galactosamine-sensitized mice by a tumor necrosis factor-dependent pathway

PURPOSE: To investigate the clonal origin of malignant cells in recurrent superficial bladder cancer. MATERIALS AND METHODS: We compared the protein expression of p53 and retinoblastoma (Rb) by immunohistochemistry using antibody P1801 and PMG3-245, respectively, in 13 patients at the time of primary superficial bladder cancer resection (6 Ta and 7 T1) and their 15 corresponding recurrences of disease. Mutations in p53 and Rb were inferred on the basis of immunoperoxidase staining. RESULTS: At the time of initial tumor resection, a p53 mutation was observed in 5 patients (39%) and an Rb mutation was observed in 3 (23%). The p53/Rb mutation status of recurrent bladder cancers completely matched their corresponding primary bladder cancer. CONCLUSIONS: The chance that recurrent bladder cancer originated from independent clones in this study was extremely small (p < 10(-6)). This result strongly supports the monoclonal origin of recurrent superficial bladder cancer.     

Congenital epulis in the newborn

The authors report a case of congenital epulis in the lower gum of a new born female. This rare benign tumor of the newborn is histologically characterized by the granular aspect of its cells. It occurs more frequently in females than in males. Differential diagnosis mainly concerns Abrikossoff tumor whose histogenesis and evolution are different. The distinctive features of epulis are the presence of a fusiform cell component and the negativity of the granular cells for PS100.     

Mastication forces and implant-bearing surface

This article discusses the shift of emphasis in implantology from the phenomenon of osseointegration of implants to the accurate fabrication of the prosthesis, recognizing the implant/prosthesis unit as an actual replica rather than a replacement of the missing tooth. The study of kinetics with its succession of mandibular cycles is used to discuss the integration of mastication and occlusion. The importance of periimplant ligament in natural teeth is discussed, along with the impact of its absence on implant mobility. The impact of the bone types and the root surface architecture on the implant-bearing surface is presented along with the stress of the mastication forces. All these factors have to be considered in the treatment planning and effectively communicated to the laboratory. The learning objective of this article is to provide updated information in those areas for the reader.     

Serum hepatitis B markers in blood donors in Venezuela. What do they mean?

Adenocarcinomas metastatic to brain from lung or colon may pose differentiation difficulties. Ultrastructurally, both may have brush borders with rootlets. This study examines the ultrastructural morphology and immunohistochemical expression of villin (associated with rootlets), cytokeratin 7 (present in lung adenocarcinomas), and cytokeratin 20 (present in colon adenocarcinomas) in 19 formalin-fixed sequential surgical biopsies of lung adenocarcinomas metastatic to brain as compared to 13 colonic adenocarcinoma metastases. Of lung tumor metastases, mucinous differentiation with rootlets was most common [6/19(32%)]. All colon tumor metastases were cytokeratin 7(-), 20(+), and profusely villin(+). Well-formed rootlets were seen. All lung metastases were cytokeratin 7(+) and 20(-). 5/6(83%) lung metastases with rootlets were focally villin(+). 12/13(95%) without rootlets were villin(-). Rootlets are extremely common in lung adenocarcinoma metastatic to brain. Villin immunoreactivity closely correlates with rootlets. Its distribution is a useful adjunct to cytokeratin 7 and 20 in differentiation of lung versus colon adenocarcinomas metastatic to the brain.     

Comparative Studies on non-histone chromatin proteins from calf and rat pancreas

1. SDS-polyacrylamide gel electrophoresis showed some slight quantitative species-dependent differences in total non-histone chromatin proteins and nuclear phosphoproteins (phenol-soluble fraction of non-histone chromatin proteins) but no differences in the DNA-binding non-histone proteins. 2. Comparative studies on DNA and RNA content, and amino acid composition of nuclear phosphoproteins and DNA-binding non-histone proteins of pancreas demonstrated a striking similarity between the two species studied.