scholarly journals Biosynthesis of the carbohydrate portion of immunoglobulins. Incorporation of radioactive fucose into immunoglobulin G1 synthesized and secreted by mouse plasma-cell tumour MOPC 21

1971 ◽  
Vol 125 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Fritz Melchers

Incorporation of radioactive fucose into the immunoglobulin G1 myeloma protein secreted by mouse plasma-cell tumour MOPC 21 is stereospecific for the l-isomer. Heavy chains of the secreted form of the myeloma protein carry 90% of the label in fucose residues of their carbohydrate moieties. A small but significant amount of the intracellular immunoglobulin G1 of the mouse plasma-cell tumour MOPC 21 appears to be labelled. Serum in the incubation medium supplies low-molecular-weight diffusible substances necessary to maintain continuous secretion of fucose-labelled myeloma protein beyond 2–3h, and of leucine-labelled myeloma protein beyond 6–8h. In medium containing extensively dialysed serum the secretion of leucine- and fucose-labelled myeloma protein can be restored by the addition of 250μm-d-mannose, 250μm-d-galactose and 250μm-glucosamine. Synthesis and secretion appear to be facilitated in the presence of these sugars, although secretion of myeloma protein devoid of terminal fucose residues is possible for a limited time-period.

1958 ◽  
Vol 108 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Daniel Nathans ◽  
John L. Fahey ◽  
Michael Potter

The origin of the myeloma protein found in mice bearing the plasma cell tumor X5563 has been investigated. Specific activity-time curves of the myeloma proteins isolated from the tumor and from the plasma of these animals were compared following intravenous injection of L-lysine-C14. The results indicate that myeloma protein is synthesized in the plasma cell tumor.


1971 ◽  
Vol 125 (1) ◽  
pp. 235-240 ◽  
Author(s):  
R. M. E. Parkhouse ◽  
Fritz Melchers

Incorporations of radioactive mannose, galactose and fucose into MOPC 104E mouse plasma-cell tumour suspensions suggest a stepwise addition of carbohydrate residues to immunoglobulin M (IgM) during the process of secretion. Mannose and glucosamine residues are added at an early stage, whereas galactose and fucose are added just before, or at the time that, IgM leaves the cell. Free light chains secreted in excess by the same tumour cells incubated with mannose, galactose or fucose contained barely detectable amounts of radioactivity.


1980 ◽  
Vol 192 (3) ◽  
pp. 887-895 ◽  
Author(s):  
Emile Van Schaftingen ◽  
Louis Hue ◽  
Henri-Géry Hers

1. Recycling of metabolites between fructose 6-phosphate and triose phosphates has been investigated in isolated hepatocytes by the randomization of carbon between C(1) and C(6) of glucose formed from [1-14C]galactose. 2. Randomization of carbon atoms was regularly observed with hepatocytes isolated from fed rats and was then little influenced by the concentration of glucose in the incubation medium. It was decreased by about 50% in the presence of glucagon. 3. Randomization of carbon atoms by hepatocytes isolated from starved rats was barely detectable at physiological concentrations of glucose in the incubation medium, but was greatly increased with increasing glucose concentrations. It was nearly completely suppressed by glucagon. These large changes can be attributed to parallel variations in the activity of phosphofructokinase. 4. The main factors that appear to control the activity of phosphofructokinase under these experimental conditions are the concentration of fructose 6-phosphate, the concentration of fructose 1,6-bisphosphate and also the affinity of the enzyme for fructose 6-phosphate. 5. The affinity of phosphofructokinase for fructose 6-phosphate was diminished by incubation of the cells in the presence of glucagon and also by filtration of an extract of hepatocytes through Sephadex G-25 and by purification of the enzyme. When assayed at 0.25 or 0.5mm-fructose 6-phosphate, the activity of phosphofructokinase present in a liver Sephadex filtrate was increased by a low-molecular-weight effector, which could be isolated from a liver extract by ultrafiltration, gel filtration or heat treatment, but was rapidly destroyed in trichloroacetic acid, even in the cold. This effector appears to be a highly acid-labile phosphoric ester. Its concentration was greatly increased in hepatocytes incubated in the presence of glucose and was decreased in the presence of glucagon.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5120-5120
Author(s):  
Johnny McHugh ◽  
Cathal O’Ceallaigh ◽  
Colm Keane ◽  
Brian W. Otridge ◽  
Peter O’Gorman

Abstract PURPOSE: The combination of thalidomide and dexamethasone has been shown to have excellent antimyeloma activity in both relapsed and newly diagnosed patients. This combination offers a potential oral, less toxic alternative to standard regimens. This single-centre retrospective study evaluates the activity of the combination of thalidomide and dexamethasone in patients with newly diagnosed multiple myeloma attending the haematology department of the Mater Misericordiae University Hospital, Dublin. METHODS: Forty-six patients with newly diagnosed multiple myeloma between April 2000 and April 2006 were treated with thalidomide and dexamethasone as first line treatment. The median age of the patients was 70 years (range 46 to 88 years). The median serum paraprotein level was 32g/l (range 2 to 99g/l). The median bone marrow plasma cell percentage was 40% (range 10% to 99%) The first twenty-two patients were commenced on thalidomide at 200mg od with the dose increased by 200mg every two weeks if tolerated to a maximum of 800mg od. The most recent twenty-four patients were commenced on thalidomide at 100mg od with the dose increased to a maximum of 200mg if tolerated. All patients received dexamethasone 40mg per day on days 1–4, 9–12 and 17–20 ot the first cycle and for a four day pulse every four weeks for subsequent cycles. RESULTS: The response rate was 67.4% when assessed by Blade criteria (50% reduction in serum myeloma protein and 90% reduction of urine myeloma protein on at least two occasions for a minimum of 6 weeks). A complete response was observed in 10.9% of patients. There was no significant difference in response rates between the higher thalidomide dose group and the lower thalidomide dose group. The main toxicities included constipation in 57.8%, hyperglycaemia in 33.3%, peripheral neuropathy in 22.2%, drowsiness in 15.6%, peripheral oedema in 15.6%, venous thromboembolism in 11.1%, rash in 11.1% and proximal myopathy in 8.9%. Routine anticoagulation was not used although patients with additional risk factors for venous thromboembolism received prophylactic dose low molecular weight heparin and in total 53.3% of patients were receiving either aspirin, warfarin or low molecular weight heparin at the time of treatment. There was no significant difference between the two thalidomide dose groups in terms of frequency of toxicities. However 27.3% of patients in the higher thalidomide dose group had their treatment stopped within one month due to toxicities compared to 4.2% in the lower dose group. CONCLUSION: The combination of thalidomide and dexamethasone is safe and effective in the treatment of newly diagnosed multiple myeloma. There is less treatment-limiting toxicity and no loss of efficacy with lower doses of thalidomide.


Nature ◽  
1958 ◽  
Vol 181 (4617) ◽  
pp. 1213-1214 ◽  
Author(s):  
A. F. HOWATSON ◽  
E. A. McCULLOCH

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