Cricetinae

This work reports the validation of a simple CZE method to be used in quality control of recombinant human glycosylated interleukin-7 (rhIL-7) batches produced in Chinese Hamster Ovary (CHO) cells. The separation buffer was a 25mM sodium borate at pH 10 containing 12mM diaminobutane (DAB) used as a dynamic coating agent of the capillary. This method allowed the separation of seven peaks ranging from low to high sialylated glycoforms. An extensive study on conditioning methods of the capillary has been conducted to yield repeatable results. Excellent RSD of EOF mobility (less than 0.6%) was obtained when conditioning included capillary equilibration under virtual analyses and storage in 0.1M NaOH overnight. Method specificity has been demonstrated to be able to discriminate different rhIL-7 glycoforms produced in CHO from formulation matrix. Linearity was demonstrated between 0.5 and 4mg/mL. LOQ was 0.5mg/mL. Repeatability (RSD<1.4 and 3.3% for t(m) and A%, respectively), intermed...

Prostacyclin (PGI 2 ) possesses various physiological functions, including modulation of nociception, inflammation and cardiovascular activity. Elucidation of these functions has been hampered by the absence of selective IP receptor antagonists. ... Two structurally distinct ...

ErbB tyrosine kinase receptors mediate mitogenic signal cascade by binding a variety of ligands and recruiting the different cassettes of adaptor proteins. In the present study, we examined heregulin (HRG)-induced signal transduction of ErbB4 receptor and found that the phosphatidylinositol 3′-kinase (PI3K)-Akt pathway negatively regulated the extracellular signal-regulated kinase (ERK) cascade by phosphorylating Raf-1 on Ser259. As the time-course kinetics of Akt and ERK activities seemed to be transient and complex, we constructed a mathematical simulation model for HRG-induced ErbB4 receptor signalling to explain the dynamics of the regulation mechanism in this signal transduction cascade. The model reflected well the experimental results observed in HRG-induced ErbB4 cells and in other modes of growth hormone-induced cell signalling that involve Raf-Akt cross-talk. The model suggested that HRG signalling is regulated by protein phosphatase 2A as well as Raf-Akt cross-talk, and p...

Serum albumin is the most abundant plasma protein and has a long half-life due to neonatal Fc receptor (FcRn) mediated transcytosis by many cell types including proximal tubule cells of the kidney. Albumin also interacts with, and is modified by, many small and large molecules. Therefore, the focus of this study was to address the impact of specific known biologic albumin modifications on albumin-FcRn binding and cellular handling. Binding at pH 6.0 and 7.4 was performed since FcRn binds albumin strongly at acidic pH and releases it following transcytosis at physiological pH. Equilibrium dissociation constants (KDs) were measured using microscale thermophoresis. Since studies have shown that glycated albumin is excreted in the urine at a higher rate than unmodified albumin we studied glucose and methylgloxal modified albumins (21day). All had reduced affinity to FcRn at pH 6.0 suggesting these albumins would not be returned to the circulation via the transcytotic pathway. To address...

Specific regions in the rodent larynx exhibit cellular changes in response to inhaled xenobiotics. These regions include the base of the epiglottis, ventral pouch, and medial surfaces of the vocal processes of the arytenoid cartilages. There are interspecies differences among laboratory rodents in the microscopic anatomy of these sensitive areas of the laryngeal mucosa. In CRL:CD strain Sprague-Dawley rats, the

Microvascular hematocrit and its possible relation to oxygen supply were systematically examined. We studied the red cell volume fraction (hematocrit) in arterial blood and in capillaries under a variety of circumstances. Control capillary hematocrit averaged 10.4 +/- 2.0% (SE) and arteriolar (14.2 micrometer ID) hematocrit averaged 13.9 +/- 1.2% in cremaster muscles of pentobarbital-anesthetized hamsters. Carotid artery hematocrit was 53.2 +/- 0.6%. The low microvessel hematocrit could not be entirely explained by a high red cell flux through arteriovenous channels other than capillaries (shunting). Hematocrit was not only low at rest, but varied with physiological stimuli. A 1-Hz muscle contraction increased capillary hematocrit to 18.5 +/- 2.4%, and maximal vasodilation induced a rise to 39.3 +/- 9.5%. The quantitative relations between capillary red cell flux, arterial hematocrit, and total blood flow could be explained by a two-element model of microvascular blood flow that inc...

Two different classes of hamster cell mutants (25RA cells and M1 cells) express opposite phenotypes in sterol dependent regulation. In 25RA cells, sterols added in growth medium fail to cause down-regulation of sterol synthesis rate and low density lipoprotein (LDL) receptor activity, while in M1 cells, removal of lipids from growth medium fail to cause up-regulation of sterol synthesis rate

To test the activity of novel hydroxyvitamin D(3) analogs (20(OH)D(3), 20,23(OH)(2)D and 1,20(OH)(2)D(3)) on normal and malignant melanocytes in comparison to 1,25(OH)(2)D(3). Human epidermal melanocytes and human and hamster melanoma cells were used to measure effects on proliferation and colony formation in monolayer and soft agar. Cell morphology and melanogenesis were also analyzed. QPCR was used to measure gene expression. Novel secosteroids inhibited proliferation and colony formation by melanoma cells in a similar fashion to 1,25(OH)(2)D(3), having no effect on melanogenesis. These effects were accompanied by ligand-induced translocation of VDR to the nucleus. In normal melanocytes 1α-hydroxyderivatives (1,25(OH)(2)D(3) and 1,20(OH)(2)D(3)) had stronger anti-proliferative effects than 20(OH)D(3) and 20,23(OH)(2)D(3), and inhibited dendrite formation. The cells tested expressed genes encoding VDR and enzymes that activate or inactivate vitamin D(3). Novel secosteroids show pot...

A comprehensive study of cholesterol, bile acid, and lipoprotein metabolism was undertaken in two strains of hamster that differed markedly in their response to a sucrose-rich/low fat diet. Under basal conditions, hamsters from the LPN strain differed from Janvier hamsters by a lower cholesterolemia, a higher postprandial insulinemia, a more active cholesterogenesis in both liver [3- to 4-fold higher 3-hydroxy 3-methylglutaryl coenzyme A reductase (HMG-CoAR) activity and mRNA] and small intestine, and a lower hepatic acyl-coenzyme A:cholesterol acyltransferase activity. Cholesterol saturation indices in the gallbladder bile were similar for both strains, but the lipid concentration was 2-fold higher in LPN than in Janvier hamsters. LPN hamsters had a lower capacity to transform cholesterol into bile acids, shown by the smaller fraction of endogenous cholesterol converted into bile acids prior to fecal excretion (0.34 vs. 0.77). In LPN hamsters, the activities of cholesterol 7alpha-h...