Alterations in the structure of the electrical double layer adjacent to a charged membrane arising from electromagnetically induced changes in the activity of membrane bound enzymes

Electromagnetic fields of very low amplitude have been reported to influence a number of cellular functions. Many of these effects have a high degree of frequency specificity. Herein it is suggested that some of these reported results could be explained by a fieldinduced alteration in the enzymic activity of integral membrane proteins. It is shown that such a field-induced transition from an initial nonequilibrium steady-state to a final nonequilibrium steady-state can lead to an alteration in the concentration profiles of those charged species in the cell's ambient electrolyte that comprise the so-called electrical double layer. Examples of variations in the concentration profiles of those ions that react with a membrane-bound enzyme, as well as nonreacting ionic species, are given. The modulation of such effects by systematic variations in extracellular pH and ionic strength is discussed.     

Ring 17 chromosome detected by amniocentesis.

A fetus with a 46,XX,r(17) karyotype identified initially by amniocentesis and confirmed by banding studies is described. No significant phenotypic abnormalities were identified despite isolation of the ring chromosome from multiple fetal tissues. This paucity of abnormal features of gross development is consistent with findings in 3 previously reported patients with ring 17 chromosomes.     

Successful maintenance of suckling rat ileum in organ culture.

Ileum from rats 4, 9, 11, 12, and 15 days old can best be maintained for 24 hours in a system using Hanks' Balanced Salt Solution without fetal calf serum, at 25 degrees C and 21% O2. Suckling rat duodenum and jejunum were difficult to maintain well for 24 hours in this system or a variety of other systems that were tried. A temperature of 37 degrees C hastened deterioration of duodenum, jejunum or ileum. With ileum, 3H-thymidine and 14C-leucine were increasingly incorporated into DNA and protein over the 24-hour period. Light microscopy, as well as scanning and transmission electron microscopy, showed very good preservation of the ileum after 24 hours. The addition to the medium of hydrocortisone, 1 micron, and thyroxine, 0.01 micron, alone or in combination, did not change DNA or protein synthesis, or morphology, possibly because of the relatively short (24 hour) time period. Our organ culture system emphasizes the differences between suckling rat ileum and the rest of the intestine, and provides a new tool for evaluating, over a 24-hour period, the developing rat small intestine.     

Semi-supervised methods to predict patient survival from gene expression data

An important goal of DNA microarray research is to develop tools to diagnose cancer more accurately based on the genetic profile of a tumor. There are several existing techniques in the literature for performing this type of diagnosis. Unfortunately, most of these techniques assume that different subtypes of cancer are already known to exist. Their utility is limited when such subtypes have not been previously identified. Although methods for identifying such subtypes exist, these methods do not work well for all datasets. It would be desirable to develop a procedure to find such subtypes that is applicable in a wide variety of circumstances. Even if no information is known about possible subtypes of a certain form of cancer, clinical information about the patients, such as their survival time, is often available. In this study, we develop some procedures that utilize both the gene expression data and the clinical data to identify subtypes of cancer and use this knowledge to diagnose future patients. These procedures were successfully applied to several publicly available datasets. We present diagnostic procedures that accurately predict the survival of future patients based on the gene expression profile and survival times of previous patients. This has the potential to be a powerful tool for diagnosing and treating cancer.     

Proteomics-based target identification: bengamides as a new class of methionine aminopeptidase inhibitors

LAF389 is a synthetic analogue of bengamides, a class of marine natural products that produce inhibitory effects on tumor growth in vitro and in vivo. A proteomics-based approach has been used to identify signaling pathways affected by bengamides. LAF389 treatment of cells resulted in altered mobility of a subset of proteins on two-dimensional gel electrophoresis. Detailed analysis of one of the proteins, 14-3-3gamma, showed that bengamide treatment resulted in retention of the amino-terminal methionine, suggesting that bengamides directly or indirectly inhibited methionine aminopeptidases (MetAps). Both known MetAps are inhibited by LAF389. Short interfering RNA suppression of MetAp2 also altered amino-terminal processing of 14-3-3gamma. A high resolution structure of human MetAp2 co-crystallized with a bengamide shows that the compound binds in a manner that mimics peptide substrates. Additionally, the structure reveals that three key hydroxyl groups on the inhibitor coordinate the di-cobalt center in the enzyme active site.     

Mitochondrial Carbonic Anhydrase VA Deficiency Resulting from CA5A Alterations Presents with Hyperammonemia in Early Childhood

Four children in three unrelated families (one consanguineous) presented with lethargy, hyperlactatemia, and hyperammonemia of unexplained origin during the neonatal period and early childhood. We identified and validated three different CA5A alterations, including a homozygous missense mutation (c.697T>C) in two siblings, a homozygous splice site mutation (c.555G>A) leading to skipping of exon 4, and a homozygous 4 kb deletion of exon 6. The deleterious nature of the homozygous mutation c.697T>C (p.Ser233Pro) was demonstrated by reduced enzymatic activity and increased temperature sensitivity. Carbonic anhydrase VA (CA-VA) was absent in liver in the child with the homozygous exon 6 deletion. The metabolite profiles in the affected individuals fit CA-VA deficiency, showing evidence of impaired provision of bicarbonate to the four enzymes that participate in key pathways in intermediary metabolism: carbamoylphosphate synthetase 1 (urea cycle), pyruvate carboxylase (anaplerosis, gluconeogenesis), propionyl-CoA carboxylase, and 3-methylcrotonyl-CoA carboxylase (branched chain amino acids catabolism). In the three children who were administered carglumic acid, hyperammonemia resolved. CA-VA deficiency should therefore be added to urea cycle defects, organic acidurias, and pyruvate carboxylase deficiency as a treatable condition in the differential diagnosis of hyperammonemia in the neonate and young child.     

Laboratory Animal Management Assistant (LAMA): a LIMS for active research colonies

Laboratory Animal Management Assistant (LAMA) is an internet-based system for tracking large laboratory mouse colonies. It has a user-friendly interface with powerful search capabilities that ease day-to-day tasks such as tracking breeding cages and weaning litters. LAMA was originally developed to manage hundreds of new mouse strains generated by a large functional genomics program, the Pleiades Promoter Project (http://www.pleiades.org). The software system has proven to be highly flexible, suitable for diverse management approaches to mouse colonies. It allows custom tagging and grouping of animals, simplifying project-specific handling and access to data. Finally, LAMA was developed in close collaboration with mouse technicians to ease the transition from paper- or Excel-based management systems to computerized tracking, allowing data export in a popular spreadsheet format and automatic printing of cage cards. LAMA is an open-access software tool, freely available to the research community at http://launchpad.net/mousedb.