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Biomedical subjects

C Harbour

Publications and source records attributed to C Harbour.

36 records · Page 2Linked to original sources
PubMed1990

A comparison of different culture methods for hybridoma propagation and monoclonal antibody production.

A major variable to consider in the production of biologicals from mammalian cell cultures is the mode of operation, be it a batch, continuous, perfusion, fed-batch or other production method. The final choice must consider a number of fundamental and economic issues. Here we present some antibody production data from different cell lines using different modes of production and discuss the important factors for consideration in choosing a production strategy. It was found that the productivity of batch cultures was lower than that obtained in continuous and perfused cultures, but that productivity could be improved by implementing suitable feeding strategies. The antibody productivity of one cell line, MCL1, during exponential phase was not affected by media type or glucose level. The maximum productivity of two cell lines in continuous culture was found to occur at dilution rates below the maximum, from 0.019 to 0.030 hr-1.

Animals↗
PubMed1989

Prevalence of peritonitis-associated coagulase-negative staphylococci on the skin of continuous ambulatory peritoneal dialysis patients.

The predominance of coagulase-negative staphylococci as normal skin flora is thought to be a factor in their association with episodes of peritonitis in patients undergoing continuous ambulatory peritoneal dialysis. We investigated the prevalence of peritonitis-associated strains on the skin of 28 patients undergoing peritoneal dialysis. Coagulase-negative staphylococci were the most frequently isolated organisms, comprising 47% of peritoneal dialysis fluid isolates and 59% of body site isolates. A total of 142 coagulase-negative staphylococci were speciated, tested for their antimicrobial sensitivity and slime production, and identified by phage typing and plasmid-profile analysis. Staphylococcus epidermidis was the most commonly identified species from both peritoneal dialysis fluid (73%) and body sites (53%). Multiple antibiotic resistance was common, and the greater proportion of isolates were resistant to methicillin; 63.6% of peritoneal dialysis fluid isolates and 61.7% of body-site isolates. S. haemolyticus isolates were significantly more resistant to methicillin than other species. By phage typing and plasmid-profile analysis it was shown that peritonitis was rarely caused by skin-colonizing strains. In only 3 of 14 patients were peritonitis-associated strains isolated as skin colonizers, and no patients developed peritonitis due to organisms previously isolated as skin colonizers.

Bacteriophage Typing↗
PubMed1989

A study of coagulase-negative staphylococci isolated from clinically significant infections at an Australian teaching hospital.

Some 151 isolates of coagulase-negative staphylococci isolated from patients at an Australian teaching hospital were characterized by biochemical analysis, antibiotic sensitivity patterns and slime production. S. epidermidis was the predominant species (64%) isolated from clinically significant infections, and all S. epidermidis isolates from true bacteremias produced slime. Forty-nine per cent were resistant to methicillin and 61% to gentamicin. S. haemolyticus isolates from clinically significant infections also showed antibiotic resistance and 80% were resistant to more than five antibiotics. The importance of coagulase-negative staphylococci as pathogens in this large teaching hospital was confirmed.

Anti-Bacterial Agents↗
PubMed1987

Blood grouping with monoclonal antibodies.

The Technicon BG15 automated blood grouping machine has been used to type over 32,000 blood donors with a monoclonal anti-A and anti-B. The results of using these antibodies in parallel with conventional human antisera will be presented along with preliminary data obtained with the Groupamatic 2000 using a different anti-A. A monoclonal anti-N reagent has been assessed for its suitability for use as a blood grouping reagent in microplate assays by testing 10,000 blood donors in parallel with Vicia graminea anti-N lectin or rabbit anti-N. There was complete correlation between the results obtained with the monoclonal antibodies and conventional reagents.

Antibodies, Monoclonal↗
PubMed1986

Blood grouping with monoclonal anti-N antibodies.

Four monoclonal antibodies (N1, N3, N4 and N5) with specificity for the N blood group have been produced from fusions in which human erythrocytes were used as the immunizing stimulus. N1 and N3 differed from N4 and N5 with regard to their serological specificities and pH optima. Antibody N3 has been assessed for its suitability as a blood grouping reagent by testing 10,767 blood donors in parallel with Vicia graminea anti-N lectin or rabbit anti-N. There was complete correlation between the results obtained with the monoclonal and conventional reagents providing strong evidence that N3 is a reliable and potent blood grouping reagent.

Antibodies, Monoclonal↗
PubMed1986

Expression of blood group antigens by cultured human epidermal cells.

The presence of blood group antigens on the surface of cultured human epidermal cells has been demonstrated using monoclonal antibody supernatants in indirect immunoperoxidase and immunofluorescence tests. An isoantigen pattern, consistent with the blood group of the donor infant, was detected in cultures derived from 10 different foreskin specimens, and in sections of the epidermis of 5 of these specimens. The A, B, and H antigens were found on the surface of cultured keratinocytes which resembled those of the spinous and granular cell layers of the in vivo epidermis. These antigens were readily detectable throughout the majority of the lifespan of the cells in vitro. This finding may be of relevance to those contemplating allograft transplantation of cultured human epidermis.

ABO Blood-Group System↗
PubMed1985

Growth kinetics of hybridoma cells: (1) The effects of varying foetal calf serum levels.

The growth kinetics, i.e. growth rate, cell yield and antibody production, of two murine hybridoma cell lines have been studied in several commercial media at different FCS levels in static 25 cm2 flask cultures. Reduction of FCS levels from 10% to 5% did not affect significantly the antibody yield whereas at 2% and 1% FCS levels growth rate, cell and antibody yield were reduced significantly in all media. Considerable differences were noted in the maximum cell populations obtained in the different media, with IMDM producing the highest cell and antibody yields; IMDM greater than HiGem greater than DME greater than RPMI. The cell lines did not grow in the absence of FCS but did grow in the presence of basal medium supplemented with insulin and transferrin at 10 mg per L. Both cell lines were stable during several months' passage in this medium. A supplement containing human albumin or BSA at 1 g per L combined with the insulin and transferrin (10 mg per L) could replace 1% FCS in DME without significantly affecting the cell yields of B6.

Animals↗
PubMed1985

Growth kinetics of hybridoma cells: (2) The effects of varying energy source concentrations.

Commercial media used for the growth of hybridoma cells contain different glucose concentrations. We have attempted to establish the optimal levels of glucose required for maximum hybridoma cell yields by studying the energy source metabolism of two murine hybridoma cell lines in several commercial media in static 25 cm2 flask cultures. The glucose and lactate quotients and growth yields from glucose of the two cell lines were similar in all media. Glucose limited growth in DME containing lg/L. Glucose supplementation to 2g/L in DME significantly increased cell and antibody yields. When fructose was used as a substitute for glucose the fructose quotient of one cell line was found to be similar to its glucose quotient whereas that of the other cell line was significantly reduced compared to its glucose quotient.

Animals↗
PubMed1984

Monoclonal antibodies specific for blood groups A and B.

Monoclonal antibodies have been produced with specificity for human blood group A following the immunization of mice with group A1 cells. The antibodies produced were of low titre and poor avidity and were therefore unsuitable as manual grouping reagents. However, in 6,524 automated tests on the Technicon BG15 monoclonal anti-A performed as well as the standard human anti-A reagent. Monoclonal anti-B antibodies were produced from a BALB/c mouse immunized with a combination of group B cells and B substance. One antibody, B/C9/F7, performed well in screening tests with avidity reactions less than 10 seconds with all B, A1B and A2B cells tested. This antibody performed with 100% accuracy in an automated test trial involving 1,018 samples. The suitability of these antibodies as blood grouping reagents is discussed.

ABO Blood-Group System↗
PubMed1984

An interesting monoclonal anti-N produced following immunization with human group O, NN erythrocytes.

Spleen cells from Balb/c mice given multiple injections of intact human erythrocytes (group O, NN) were fused with NS1 myeloma cells. Culture fluids from the resulting hybrid cells were screened for agglutinating antibody against a panel of erythrocytes. One cell line, 2/23, secreted an IgM antibody which reacted more strongly with NN than with MM cells. Neuraminidase or papain treatment of erythrocytes abolished agglutination whereas trypsin treatment did not. Reactions with U- erythrocytes of different MN phenotypes confirmed the anti-N specificity of monoclonal antibody 2/23. This is the first report of monoclonal anti-N stimulated by the immunization of mice with intact erythrocytes.

ABO Blood-Group System↗
PubMed1979

The prevalence of hepatitis B surface antigen and its antibody in blood donors and high risk groups in Iran.

The prevalence of HBsAg and anti-HBs among voluntary blood donors, professional blood donors, INBTS laboratory staff, haemophiliacs and the patients and medical personnel of three haemodialysis centres was compared. The 3.4% incidence of HBsAg found among 168,890 voluntary donors was significantly less than the 8.4% found among 378 professional blood donors. The prevalence of HBsAg was higher in male than in female donors, and also higher in single than in married donors. Prevalence of HBsAg was unrelated to ABO-Rh blood group but was related to age. Anti-HBs was found in 30% of voluntary blood donors, 67% of professional donors, 68% of haemodialysis patients, 39% of haemodialysis staff, 86% of haemophiliacs and in only 4.8% of HBsAg carriers. Subtyping of HBsAg found in 100 voluntary donors showed 65 were ay; 5 ad; 10 ad + ay and 20 were untypable.

Adult↗
PubMed1978

Cell-mediated immunity in professional and voluntary blood donors.

Cell-mediated immunity (CMI) was compared in professional and voluntary blood donors. Depressed CMI in professional donors was revealed by the presence of significantly lower numbers of positive delayed reactive hypersensitivity responses to Candida albicans, streptokinase and streptodornase, as well as a decrease in lymphoblast transformation response to phytohaemagglutinin. Furthermore, the serum protein and albumin levels in professional donors did not correlate with the depression in CMI. The blood of professional blood donors should be considered to be a poor source of therapeutic immune cell fractions.

Adult↗
PubMed1978

Professional and voluntary blood: a preliminary study in Iran.

Among professional and voluntary blood donors in Tehran HBsAg carriers and RPR positives were found more frequently in the former group. The levels of haemoglobin, serum total protein and serum immunoglobulins G, A and M were significantly lower in commercial blood. Measurement of transferrin saturation showed that one-third of professional donors were quite severely iron deficient. For fractionation purposes the maximum theoretical yield from commercial plasma is 16% less IgG than from plasma of voluntary donors, 21% less total immunoglobulins and 20% less albumin.

Blood Donors↗
PubMed1978

Cellular and plasma-associated phagocytic defects amongst Iranian blood donors.

Peripheral blood leucocytes from 30 grossly anaemic professional blood donors were investigated for phagocytosis, intracellular killing and chemotaxis. The nitro-blue tetrazolium test was positive in 29 donors and negative in 1. Professional donors' cells in the presence of normal plasma were unable to phagocytose successfully and Candida killing and opsonization were defective when donors' plasma was used in the presence of normal cells. Chemotaxis of professional donors' cells to Ag/Ab-treated normal plasma was reduced as was chemotactic activity of normal cells in both Ag/Ab- and LPS-treated professional donors' plasma.

Anemia, Hypochromic↗
PubMedDate not supplied

Analysis of multivariables during porcine liver digestion to improve hepatocyte yield and viability for use in bioartificial liver support systems.

In order to achieve optimal BALSS function, preparation of porcine hepatocytes with high yield, viability, and P450 activity is known to be important. To date hepatocyte yields have varied from 0.58 x 10(10) to 3.45 x 10(10) and viabilities from 75% to 95% within and between laboratories, even when using the same digestion methods and procedures, indicating that hepatocyte isolation during porcine liver digestion is not fully optimized. The aim of this work was to identify the critical parameters affecting cell recovery during porcine liver harvesting by investigating 21 variables involved in the process, including pig body and liver weight, different digestion times of perfusates, pH, a range of concentrations of sodium and chloride in EDTA, and collagenase perfusates. Univariate and multivariate analysis of a retrospective study (n = 23) revealed that low perfusate pH during the process of digestion had a positive effect on hepatocyte yield (p < 0.05), while high (relative) concentrations of sodium and chloride in the perfusates had significant negative effects on hepatocyte viability (both p < 0.05). Sodium and chloride had narrow optimal ranges for achieving a >90% viability. These findings were then tested in a prospective study (n = 10) and further verified. High hepatocyte viabilities (91.8+/-1.6% p = 0.036) and yields (2.56+/-0.48 x 10(10)) were achieved consistently, and P450IA1 activity was increased after sodium and chloride concentrations and pH in the perfusates were controlled. The physiological mechanism by which sodium and chloride affects hepatocyte viability during porcine liver digestion is discussed.

Animals↗