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Biomedical subjects

B E Ryman

Publications and source records attributed to B E Ryman.

At least 37 records · Page 2Linked to original sources
PubMed1979

Tissue distribution and tumour localization of 99m-technetium-labelled liposomes in cancer patients.

The possible use of liposomes (phospholipid vesicles) to direct cytotoxic drugs to tumours has led us to investigate the tissue localization of i.v. injected 99m-Tc-labelled liposomes in cancer patients. Twenty mg or 300 mg doses of liposomal lipid (7:2:1 molar ratio of phosphatidylcholine : cholesterol : phosphatidic acid) were used in a study of 13 patients with advanced cancer and one with polycythaemia rubra vera (PRV). In all cases except the patient with PRV the major site of uptake of the label was the liver and spleen. In the patient with PRV the liver uptake was greatly reduced and the major site of uptake was found in regions corresponding to marrow. With the exception of one patient with a primary hepatoma, there was no significant tumour uptake of the label.

Cholesterol↗
PubMed1978

Studies on a patient with in vivo evidence of type I glycogenosis and normal enzyme activities in vitro.

Biochemical and clinical studies on a patient with hepatic glycogen storage disease are reported. The patient showed many of the clinical and biochemical features of type I glycogenosis (glucose-6-phosphatase deficiency), but had normal activities of the following enzymes in liver tissue: glucose-6-phosphatase (EC3.1.3.9); amylo-1,6-glucosidase (EC3.2.1.33); glycogen phosphorylase (EC2.4.1.1); fructose-1,6-diphosphatase (EC3.1.3.11). The urinary excretion of 2-oxoglutaric acid was greatly increased in this patient and in a case of enzymologically proven type I glycogenosis. Abnormal 2-oxoglutaric aciduria has not been previously reported in the glycogen storage diseases. The results are discussed in relation to the possible nature of the underlying biochemical defect in patients of this type.

Fructose-Bisphosphatase↗
PubMed1978

Possible tumor localization of Tc-99m-labeled liposomes: effects of lipid composition, charge, and liposome size.

The possible in vivo distribution of liposomes after they have been directly labeled with Tc-99m has been studied in rats bearing the Walker 256 carcinoma. The importance of lipid composition, charge, and size of liposome were studied with respect to possible tumor-localizing properties. Tumor uptake was best with small, fluid-membrane, negatively charged liposomes, as indicated by the distribution of the Tc-99m label. The uptake was visualized on scintigrams.

Amines↗
PubMed1977

The effect of serum protein fractions on liposome-cell interactions in cultured cells and the perfused rat liver.

We have studied the interactions of liposomes with human skin fibroblasts and mouse P815Y mastocytoma cells in culture, and the perfused rat liver, with the following findings. 1. In all the systems studied serum was found to cause an increase in the uptake of a [14C]cholesterol label into cells from anionic and neutral liposomes and a decrease in the uptake of the label from cationic liposomes. 2. Evidence suggests that albumin enhances the exchange/transfer of [14C]-cholesterol between liposomes and cultured cells. 3. With [14C]cholesterol in the liposome bilayer and [3H]methotrexate entrapped in the aqueous spaces of the liposome, the alpha- and beta-globulin fractions of serum decreased the transfer of both labels from cationic liposomes into cultured cells and the perfused rat liver. The beta-globulin fraction caused increased leakage of methotrexate from fluid liposomes of all charges. 4. The alpha- and beta-globulin fractions of serum appear to enhance the uptake of anionic liposomes into the perfused rat liver.

Animals↗
PubMed1977

Liposome toxicity in the mouse central nervous system.

This study has shown that while some liposomes are highly toxic to the central nervous system, others, of different composition, are tolerated well in the dosage used (0.02-0.05 ml = 4-12 mg of lipid/inoculum). Those composed of lecithin-cholesterol-dicetyl phosphate or lecithin-cholesterol-stearylamine produced generalised epileptic seizures and some deaths due to respiratory failure immediately after injection,and a subsequent widespread tissue necrosis. However liposomes composed of lecithin-cholesterol-phosphatidic acid, or dipalmitoyl lecithin only, produced minimal morphological changes and by the sixth day post-injection the pathology was limited to the mechanical trauma caused by the injection. It is concluded that liposomes of appropriate composition may be sufficiently benign to use as carriers of therapeutic agents into the CNS.

Amines↗