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Biomedical subjects

B Griffiths

Publications and source records attributed to B Griffiths.

At least 19 recordsLinked to original sources
PubMed1992

Alternative strategies to the scaleup of animal cells.

The use of porous microcarriers has given manufacturers the option of having a high cell density/medium volume (10-100 L)/high specific productivity/long-term process. The advantages of the system are listed in Table 7 and many of the criteria listed in Table 1 are met. The question of being able to license products from continuous processes has been addressed and guidelines are being prepared. Methods are available to compare the master and end-of-process (extended) cell banks to ensure that no change has occurred to the cell or product. Rigid attention to process definition and validation, as well as to the definition of production lots, overcomes many of the other reservations. In conclusion, the method has been demonstrated as technically feasible, economically advantageous, and licensable and the many advantages of a high density perfusion process (listed in Table 8) make porous microcarrier technology an ideal scaleup process because it is a simple, reliable, and scalable system.

Animal Population Groups↗
PubMed1992

DNA fingerprinting--a valuable new technique for the characterisation of cell lines.

DNA fingerprinting is an important new development for the authentication of cell lines. Multilocus methods such as those developed by Alec Jeffreys provide information on a wide range of genetic loci throughout the human genome and thus give a useful genetic "snap-shot" of a cell culture. Our work has shown that Jeffreys multilocus fingerprinting method can be applied to cell lines from a wide range of animals including reptiles, birds, fish and diverse mammals. It can also differentiate very closely related cell lines including those from the same mouse strain. Routine fingerprint analysis has enabled an unprecedented level of confidence in the consistency of cell stocks. Our results demonstrate that this straightforward method represents a powerful and readily interpreted system for cell authentication and exclusion of cross-contamination.

Animals↗
PubMed1991

Differential mucin gene expression in human pancreatic and colon cancer cells.

The purpose of this study was to determine the quantity and nature of the mucins synthesized and secreted by four different pancreatic cancer cell lines. Well- to moderately-differentiated SW1990 and CAPAN-2 human pancreatic cancer cells were found to produce more high-Mr glycoprotein (HMG) than less-differentiated MIA PaCa-2 and PANC-1 cells. Most of the labelled HMG was secreted within 24 h. The results of chemical and enzymic degradation, ion-exchange chromatography and density-gradient centrifugation indicated that the HMG in SW1990 and CAPAN-2 cells has the properties expected for mucins, whereas much of the HMG in MIA PaCa-2 and PANC-1 cells may not be mucin, but proteoglycan. These results are consistent with immunoblots and Northern blots showing the presence of apomucin and apomucin mRNA in SW1990 and CAPAN-2 cells, but not in MIA PaCa-2 and PANC-1 cells. The Western blots and Northern blots also show that SW1990 and CAPAN-2 cells, like breast cancer cells, have the mammary-type apomucin and mRNA coded by the MUC1 gene, but lack the intestinal type apomucin and mRNA coded by the MUC2 gene. In contrast, the colon cancer cell lines tested in culture express apomucin and mRNA coded by MUC2 but not by MUC1.

Adenocarcinoma↗
PubMed1990

ELFT: a gene that directs the expression of an ELAM-1 ligand.

The LECCAMs are a family of cell adhesion molecules implicated in certain inflammatory processes. ELAM-1, a LECCAM found on the surface of activated endothelial cells, can mediate adhesion of neutrophils, monocytes, and certain cell lines to endothelial cells in vitro. No ligand for any LECCAM has yet been fully characterized. Here we report the cloning of a cDNA, ELFT (ELAM-1 ligand fucosyltransferase), that can confer ELAM-1 binding activity when transfected into nonbinding cell lines. ELFT encodes a 46 kd protein that has alpha(1,3)fucosyltransferase activity, suggesting that a fucosylated carbohydrate structure is an essential component of the ELAM-1 ligand. Furthermore, ELFT is expressed specifically in cell types that bind to ELAM-1, suggesting that this enzyme is an important regulator of inflammatory events in vivo.

Amino Acid Sequence↗
PubMed1990

Assignment of the polymorphic intestinal mucin gene (MUC2) to chromosome 11p15.

A cDNA coding for a mucin expressed in intestine has recently been cloned (Gum et al. 1989). We describe here the use of this cDNA to map the gene (MUC2) to human chromosome 11 using somatic cell hybrids, and to make the regional localization to 11p15 by in situ hybridization. Analysis of the CEPH (Centre d'Etude du Polymorphisme Humain) families revealed that MUC2 forms part of the tight linkage group on 11p15 which contains HRAS, INS, TH and HBBC.

Animals↗
PubMed1989

A comparison of the effects of various stimulatory agents on t-PA secretion by normal and malignant cell lines.

Succinyl con A and acetyl con A both stimulated epithelial cells to produce similar yields of tissue plasminogen activator (t-PA) to those previously obtained with native con A. However, unlike con A, the derivatized lectins did not adversely affect cell morphology and viability, and cells treated with succinyl con A could secrete t-PA for a prolonged period. Con A and the two derivatives produced similar morphological effects in Bowes melanoma cells, but t-PA production was not increased. Elevated cyclic nucleotide concentrations did not affect t-PA production from epithelial cells, but calcium ionophore treatment generated t-PA yields similar to those obtained with lectins. Azacytidine, which enhanced t-PA production from epithelial cells, did not increase yields from Bowes melanoma cells, and also sodium butyrate, reported to increase t-PA yields from human endothelial cells, had no effect on either cell line.

Azacitidine↗
PubMed1989

An investigation of the properties and possible clinical significance of the lysosomal alpha-glucosidase GAA*2 allele.

Properties of the acid alpha-glucosidase, GAA2, the product of the GAA*2 allele have been compared with those of the common allele product GAA1, GAA2 has an altered affinity for glycogen but resembles GAA1 in its affinity for low molecular weight substrates, and also in its processing, as judged by immunoblot analysis of the denatured polypeptides. Starch gel electrophoretic analysis of fibroblasts from 15 patients with late onset glycogen storage disease type II (GSDII) failed to reveal either homozygotes or heterozygotes for the GAA*2 allele (GAA2-2 or GAA2-0) providing evidence that neither of these genotypes lead to late onset GSDII despite the impaired activity of the enzyme towards glycogen.

Alleles↗
PubMed1987

The hypervariable gene locus PUM, which codes for the tumour associated epithelial mucins, is located on chromosome 1, within the region 1q21-24.

A single hypervariable autosomal gene locus, PUM, codes for a family of mucin-type glycoproteins present in human urine, and in several other normal and malignant tissues of epithelial origin. These mucins can be detected after electrophoresis using a series of monoclonal antibodies that show a pronounced tumour specificity on immunohistochemistry. Using a recently cloned cDNA, pMUC10, coding for the core protein of the PUM coded mucins, to probe DNA isolated from a series of human-rodent somatic cell hybrids, we have assigned the PUM locus to chromosome 1. This assignment was confirmed by in situ hybridization of pMUC10 to lymphocyte metaphase chromosomes and the gene was shown to be located within the region 1q21-24.

Animals↗
PubMed1987

Splenic trauma: evaluation with CT.

Fifty-five consecutive cases of surgically proved splenic injuries were evaluated with computed tomography (CT). CT permitted correct identification of 54 splenic injuries, with one false-negative and three false-positive cases. In the single false-negative case and in two of the three false-positive cases, CT scans correctly indicated the presence of a large hemoperitoneum and other abdominal visceral lacerations and so correctly indicated the need for surgery. Of the 55 proved cases, CT demonstrated hemoperitoneum in 54 (98%), perisplenic clot in 47 (85%), splenic laceration in 39 (71%), and subcapsular hematoma in 13 (24%). Perisplenic clot can be distinguished from lysed blood in the peritoneal cavity and is a sensitive and specific sign of splenic trauma, even in the absence of visible splenic laceration. The authors conclude that CT is a highly reliable means of evaluating splenic trauma.

Adolescent↗
PubMed1986

Stimulation of tissue plasminogen activator production from epithelial cell lines.

The aim of this study was to investigate the possibility of enhancing the yield of tissue plasminogen activator (tPA) from two epithelial cell lines of normal (non-malignant) derivation grown in tissue culture. The three agents used in this investigation were chosen because of their proven enhancing effect on analogous cells or products. The anabolic hormone stanozolol was found to have no significant stimulatory effect on these cell lines. A phorbol acetate (12-O-tetradecanoylphorbol 13-acetate) caused a twofold enhancement in tPA yield but the most significant results were obtained with 5-azacytidine. This agent increased the yield by up to fourfold in small stationary cultures and threefold in large-scale microcarrier cultures. A combination of azacytidine and phorbol acetate did not have an additive effect on total yield but did alter the kinetics of tPA expression with time. Indications were that the maximum yield with these types of potentiating agents was achieved as it could not be increased by using a combination of two different agents.

Animals↗