Cell cycle dependent expression of a glucose regulated cell surface glycoprotein

Summary A cell surface associated “glucose regulated protein” has been described on nontransformed human fibroblasts. To examine the distribution of that protein on human fibroblasts specific antisera were used. The antisera was used in conjunction with indirect immunofluorescence and revealed that the glucose regulated protein was present as fibers on spread cells. Further, the antisera was used in complement mediated cytotoxicity assays to examine cells during specific stages of the mitotic cell cycle. Fibroblasts were synchronized by serum starvation, hydroxyurea inhibition, or colcemid inhibition followed by mitotic selection. The results demonstrated that the glucose regulated protein was maximally displayed during the G₁ phase of the cell cycle and minimally displayed during the S and M phases. Research was supported by contract AG00697 from the National Institutes of Health.     

TT232, A Novel Signal Transduction Inhibitory Compound in the Therapy of Cancer and Inflammatory Diseases

TT-232 is a structural analogue of somatostatin exhibiting strong and selective growth-inhibitory effects, inhibition of neurogenic inflammation, as well as general anti-inflammatory and analgesic potential without the wide-ranging endocrine side effects of the parent hormone and its “traditional” analogues. The anti-inflammatory action of TT-232 is mediated through the SSTR4 receptor, and its antitumor activity is mediated through the SSTR1 receptor and by the tumor-specific isoform of pyruvate kinase. Its mechanism of action is in line with a new era of molecular medicine called signal transduction therapy, where “false” intracellular or intercellular communication is inhibited or corrected without interfering with basic cell functions and machinery. TT232 has passed phase I clinical trials without toxicity and significant side effects, and phase II studies are running for oncological and anti-inflammatory indications, respectively. This compound has the perspective to become the first drug in molecularly targeted therapy of inflammation where a combined effect of anti-inflammatory, analgesic, and neurogenic inflammation-inhibiting activity can be achieved.     

The heart-gill preparation of the eel and its perfusion for the study of a natural membrane in situ

Summary The isolated heart-gill preparation of the eel is presented. Essentially it is a double perfusion system in which both internal and external mediums are circulated separately. The applicability of this preparation to other species of fish besides the eel is indicated.The apparatus arrangement, operative technique, and the procedure for making the most carefully controlled studies of the permeability and chemical activity of the gills are described in detail.The composition and preparation of various concentrations of a perfusion medium developed for use in this preparation are given.It is shown that the preparation retains its vital properties for a period of hours and is physiologically acceptable.The utilization of the preparation as a potent research tool in the investigation of the physiology 6f the gills and heart, as well as its use from the aspect of the properties of membranes, are discussed.Fellow of the National Research Council of America.     

The state of activation of ribulose-1,5-bisphosphate carboxylase in wheat leaves

In light and in darkness, exposure of leaf segments to CO₂-free atmospheres caused a marked reduction in extractable RuBP carboxylase activity. By contrast, darkness caused a relatively small decrease in carboxylase activity in extracts from leaf segments kept in air containing CO₂. Recovery of carboxylase activity in leaves during illumination in air after exposure to CO₂-free conditions paralleled recovery of capacity for photosynthesis; in darkness recovery of carboxylase activity in leaves was slower than in the light. Extracts from leaves exposed to CO₂-free conditions recovered activity when provided with CO₂ and Mg²⁺; there were clearly, however, substances in the extracts that modified the activity achieved and caused anomalous decreases and increases with time after extraction. Studies of the effect of orthophosphate on the activity of purified wheat carboxylase in vitro were consistent with the view that many of the effects observed on the activity of crude leaf extracts were due to orthophosphate content.     

Using a logical model to predict the growth of yeast

Background  

A logical model of the known metabolic processes in S. cerevisiae was constructed from iFF708, an existing Flux Balance Analysis (FBA) model, and augmented with information from the KEGG online pathway database. The use of predicate logic as the knowledge representation for modelling enables an explicit representation of the structure of the metabolic network, and enables logical inference techniques to be used for model identification/improvement.     

Microscopic examination of porcine conceptus-maternal interface between days 10 and 19 of pregnancy

Conceptus-maternal interactions in the pig were examined at days 10, 13, 16, and 19 of pregnancy. Contact between the chorion and uterine epithelium was not preserved on day 10, but extensive contact occurred in 3 of 5 pregnant gilts on day 13 and was related to localized differentiation of the uterine epithelium. Attachment events occurred earlier and more rapidly than previously reported, commencing in the region of the embryonic disc and progressing toward the extremities of the chorionic vesicle, with stages from apposition through attachment occurring simultaneously along a conceptus at day 13 and thereafter. Apical protuberances on maternal epithelial cells and interposing blunt chorionic processes were evident at sites of early maternal-conceptus interaction, but were reduced at regions exhibiting microvillous interdigitation. Placentation in the pig represents a developmental process consisting of a continuum of sequential events which occur over a broad time frame rather than at specific discrete times.