Isolation of skeleton-associated knobs from human red blood cells infected with malaria parasite Plasmodium falciparum.
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Animals↗
Biomedical subjects
S C Liu
Publications and source records attributed to S C Liu.
Protein immunolocalization in the spread erythrocyte membrane skeleton.
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Ankyrins↗
Molecular anatomy of the red blood cell membrane skeleton: structure-function relationships.
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Anemia, Sickle Cell↗
Deletion in erythrocyte band 3 gene in malaria-resistant Southeast Asian ovalocytosis.
Southeast Asian ovalocytosis (SAO) is a hereditary condition that is widespread in parts of Southeast Asia. The ovalocytic erythrocytes are rigid and resistant to invasion by various malarial parasites. We have previously found that the underlying defect in SAO involves band 3 protein, the major transmembrane protein, which has abnormal structure and function. We now report two linked mutations in the erythrocyte band 3 gene in SAO: (i) a deletion of codons 400-408 and (ii) a substitution, A----G, in the first base of codon 56 leading to substitution of Lys-56 by Glu-56. The first defect leads to a deletion of nine amino acids in the boundary of cytoplasmic and membrane domains of band 3. This defect has been detected in all 30 ovalocytic subjects from Malaysia, the Philippines, and two unrelated coastal regions of Papua New Guinea, whereas it was absent in all 30 controls from Southeast Asia and 20 subjects of different ethnic origin from the United States. The Lys-56----Glu substitution has likewise been found in all SAO subjects. However, it has also been detected in 5 of the 50 control subjects, suggesting that it represents a linked polymorphism. We conclude that the deletion of codons 400-408 in the band 3 gene constitutes the underlying molecular defect in SAO.
Anion Exchange Protein 1, Erythrocyte↗
Uncoupling of the spectrin-based skeleton from the lipid bilayer in sickled red cells.
The distribution of spectrin and band 3 in deoxygenated reversibly sickled cells was visualized by immunofluorescence and immunoelectron microscopy. Antibodies against band 3, the major lipid-associated transmembrane protein, labeled the entire cell body, including the entire length of the long protruding spicule, whereas antibodies against spectrin labeled only the cell body and the base region of the spicules. The results suggest that the formation of long spicules during sickling is associated with a continuous polymerization of hemoglobin S polymers, presumably through gaps in the spectrin-actin meshwork, and a subsequent uncoupling of the lipid bilayer from the submembrane skeleton.
Anemia, Sickle Cell↗
Cloning of the cDNA of alpha-momorcharin: a ribosome inactivating protein.
Using a lambda gt11 cDNA library constructed from the seeds of the bitter melon (Momordica charantia), we have obtained a full length cDNA containing the entire sequence of alpha-momorcharin by immunoscreening. The length of this cDNA is 1044 basepairs long and it consists of an open reading frame coding for a polypeptide of 286 amino acids. The first 23 residues of this polypeptide probably code for a signal sequence. The N-terminal sequence of the deduced protein is exactly identical to that determined by peptide sequencing. The sequence identity between alpha-momorcharin and other ribosome inactivating proteins, such as trichosanthin and ricin A chain, is high, i.e., 34-63%. Examination of the predicted secondary structure of alpha-momorcharin and trichosanthin indicates that these proteins have regions of high structural similarities and this may account for the common biological activities that they share, viz., abortificant, immunosuppressive, antitumor and inhibition of HIV-1.
Amino Acid Sequence↗
Immunohistochemical detection of HBsAg and HBcAg in the liver of patients with schistosomiasis japonica complicated by hepatocellular carcinoma.
In liver biopsies from 21 patients with schistosomiasis japonica complicated by hepatocellular carcinoma (HCC), 69 patients with advanced schistosomiasis japonica, and 25 patients with HCC, HBsAg and HBcAg were investigated with peroxidase-antiperoxidase technique. The positive rate of HBAg (i.e. HBsAg and/or HBcAg) in the liver of patients with schistosomiasis japonica complicated by HCC was significantly higher than in the group of advanced schistosomiasis japonica, but similar to that in cases of HCC. The location of carcinoma cells in the liver was not related to the distribution of Schistosoma ova in patients with schistosomiasis japonica complicated by HCC. The results indicated that the complication with hepatitis B virus infection may be one of the major factors involved in the development of HCC in patients with schistosomiasis japonica.
Biopsy, Needle↗
[Changes in T-lymphocyte subsets in patients with orthopedic trauma and effects of yipanzhu decoction on the impaired immune function].
The effects of yipanzhu decoction (YD) on immune function in 40 patients [2 groups, YD and normal saline (NS) group] with orthopedic trauma by taking T lymphocyte subsets as indexes were observed. The peripheral venous blood samples randomly taken from 30 healthy subjects served as control. The blood were collected within 24 hours after trauma. Then the YD and NS were respectively given to the patients in the 2 groups for 3 days, and the blood were taken 4th, 7th, 14th day after trauma for the observation of T subsets. The results revealed that before administration of YD the percentage of pan-T cells was reduced with an increased percentage of Ts cells and a decreased ratio between Th and Ts cells; 3 days after giving the drugs in YD group the percentage of pan-T cells was slightly increased, and the changed percentage of Ts cells and the ratio of Th/Ts cells mentioned above was recovered to normal, while in NS group all these indexes remained at abnormal range during the period we observed. The results suggested that YD could promote the recovery of abnormal T lymphocyte subsets in traumatized patients, and it possessed to some extent the function of immune regulation that was helpful to reduce the ratio of infection after trauma.
Adolescent↗
Hepatic carcinoma. The possibility of transcatheter chemoembolization through the portal vein.
A suspension of iodized oil and anticancer agent was injected into the portal veins of 20 rats with hepatic carcinoma and of 20 normal rats to observe its distribution in the liver and the effect on cancer tissue and normal cells. Microscopic and transmission electron microscopic examinations were carried out. Oil drops were seen in tumor cell lines, small blood vessels inside the cancer nest, the sinusoids, and the central veins. More oil drops were found in the peripheral parts of the tumor than in the central part. The distal small vessels were embolized with necrotic change of tumor cells and their subordinate normal liver cells. We conclude that portal vein part takes in the blood supply of liver cancer and tumor cell necrosis can be achieved after administration of iodized oil and anticancer agent mixture through the portal vein. Hence transcatheter treatment through the portal vein may be helpful as a supplement to intraarterial treatment of primary liver cancer and transcatheter embolization via the portal vein to reinforce the intraarterial therapy may be recommended. This procedure may cause necrosis of normal liver cells and care must be taken in clinical application.
Animals↗
Molecular defect of the band 3 protein in southeast Asian ovalocytosis.
BACKGROUND: Southeast Asian ovalocytosis is a form of hereditary elliptocytosis in which the red cells are rigid and resistant to malaria invasion. The underlying molecular defect is unknown. METHODS AND RESULTS: We studied the red cells of 54 patients with ovalocytosis and 122 normal controls. We found that ovalocytes contain a structurally and functionally abnormal band 3 protein, the principal transmembrane protein of red cells. The structural lesion of ovalocyte band 3 was revealed by limited proteolytic cleavage of the protein, which produced fragments of abnormal size that were derived from the cytoplasmic domain of the protein. The structural lesion was present in all the subjects with ovalocytosis but none of the controls. This region of band 3 serves as the principal binding site for the membrane skeleton, a submembrane protein network composed of ankyrin, spectrin, actin, and protein 4.1. The structural defect is dominantly inherited, being tightly linked with the inheritance of ovalocytosis (the probability of linkage is in excess of 10 million to 1). Ovalocyte band 3 bound considerably more tightly than normal band 3 to ankyrin, which connects the membrane skeleton to the band 3 protein. This tight binding of ovalocyte band 3 to the underlying skeleton containing ankyrin was directly confirmed in intact cells by the finding that ovalocyte band 3 had markedly reduced lateral mobility in the membrane. CONCLUSIONS: The red cells in Southeast Asian ovalocytosis carry a structurally and functionally abnormal band 3 protein. This molecular defect may underlie the increased rigidity of the red cells and their resistance to invasion by malaria parasites.
Anion Exchange Protein 1, Erythrocyte↗
Effect of hemoglobin oxidation products on the stability of red cell membrane skeletons and the associations of skeletal proteins: correlation with a release of hemin.
Oxidative injury to hemoglobin (Hb) leads to formation of methemoglobin (MetHb), reversible hemichromes (rHCRs), and irreversible hemichromes (iHCRs). iHCRs precipitate and form Heinz bodies that attach to the red cell membrane causing injury that leads to hemolysis. The molecular mechanisms of this membrane damage have not been fully elucidated. We have studied the effect of Hb oxidation products on the mechanical stability of red cell membrane skeletons and the associations of membrane skeletal proteins. Hb and MetHb stabilized the isolated membrane skeletons, whereas further oxidation to rHCRs abolished this stabilizing effect. Crude iHCRs prepared by phenylhydrazine oxidation of Hb destabilized membrane skeletons by decreasing formation of the spectrin-protein 4.1-actin complex, the effect similar to that of pure hemin. Whereas virtually no hemin was released from Hb and MetHb, high concentrations of hemin were released from crude iHCR preparations. After removal of this hemin fraction by Dowex resin, the iHCRs lost their destabilizing effect. We conclude that as the oxidation of Hb proceeds, the stabilizing effect of Hb on the membrane skeleton is gradually lost and the deleterious effect increases. The destabilization of the red cell membrane skeleton in the presence of crude iHCR is caused by release of hemin, which lowers the stability of membrane skeleton by weakening the spectrin-protein 4.1-actin interaction.
Actins↗
Alteration of the erythrocyte membrane skeletal ultrastructure in hereditary spherocytosis, hereditary elliptocytosis, and pyropoikilocytosis.
The membrane skeleton of normal erythrocytes is largely organized into a hexagonal lattice of junctional complexes (JC) crosslinked by spectrin tetramers, and occasional double tetramers and hexamers. To explore possible skeletal alterations in hereditary spherocytosis (HS), elliptocytosis (HE), and pyropoikilocytosis (HPP), we have studied the ultrastructure of the spread membrane skeletons from a subpopulation of HS patients with a partial spectrin deficiency ranging from 43% to 86% of normal levels, and in patients with HPP who, in addition to a mild spectrin deficiency, also carried a mutant spectrin that was dysfunctional, thus reducing the ability of spectrin dimers to assemble into tetramers. Membrane skeletons derived from Triton-treated erythrocyte ghosts were examined by negative staining electron microscopy. HS membrane skeletons contained structural elements, consisting of JC and spectrin filaments similar to the normal skeleton. However, less spectrin filaments interconnected the JC, and the decrease of spectrin filaments attached to JC appeared to correlate with the severity of spectrin deficiency. Only in severe HS associated with severe spectrin deficiency was the loss of spectrin sufficient enough to disrupt the overall skeletal architecture. In contrast, membrane skeletons prepared from red blood cells (RBCs) of subjects with HPP were strikingly different from HS RBCs with a comparable degree of spectrin deficiency. Although HPP RBCs were only mildly deficient in spectrin, their skeletal lattice was grossly disrupted, in contrast to only mild ultrastructural abnormalities of HS membrane skeletons with a nearly identical degree of spectrin deficiency. Skeletons from patients with common mild HE or asymptomatic carriers, carrying the mutant spectrin but having normal spectrin content, exhibited a moderate disruption of the skeletal lattice. We propose that the above differences in skeletal ultrastructure may underlie differences in the biomechanical properties and morphology of HS, HE, and HPP RBCs.
Cytoskeleton↗
Structural and functional heterogeneity of alpha spectrin mutations involving the spectrin heterodimer self-association site: relationships to hematologic expression of homozygous hereditary elliptocytosis and hereditary pyropoikilocytosis.
Defects involving alpha spectrin (Sp) are found in patients with hereditary elliptocytosis and a related disorder, hereditary pyropoikilocytosis (HPP). We have previously found that the severity of hemolysis was related to the total spectrin content of the cells and the percentage of unassembled dimeric Sp (SpD) in the membranes, which, in turn, reflected the amount of mutant Sp in the cell. However, no data are available comparing differences in the function of various alpha Sp mutations to clinical severity. We now report studies of nine homozygotes or double heterozygotes for four alpha Sp mutations: alpha 1/74, alpha 1/46, alpha 1/65, and alpha 1/61, whose red blood cells (RBCs) contained only the mutant Sp and no normal Sp. Sp alpha 1/74, Sp alpha 1/46, and alpha 1/65 homozygotes differed strikingly in the severity of hemolysis that correlated with the severity of mutant Sp dysfunction, as reflected by the fraction of unassembled SpD in the membranes and the self-association of mutant Sp on inside-out vesicles. Homozygotes for Sp alpha 1/74 had a very severe hemolytic anemia and their SpD were virtually incapable of self-association, whereas SpD alpha 1/46 were not as severely affected. The Sp alpha 1/65 homozygotes had a relatively mild hemolytic anemia and their SpD showed the least impairment of function. Ultrastructural examination of membrane skeletons from subjects whose SpD self-association was severely impaired showed gross skeletal disruption and loss of hexagonal structure. In striking contrast, the homozygote for the mildly dysfunctional Sp alpha 1/65 had only a moderate disruption of the skeleton. Some of the homozygous or doubly heterozygous subjects also exhibited a partial deficiency of Sp that correlated with a RBC morphology characteristic of HPP, namely, marked microspherocytosis with virtual absence of elliptocytes. These data demonstrate striking differences in the function and structure of various alpha Sp mutants that underlie differences in clinical expression.
Adolescent↗
3-Methoxysampangine, a novel antifungal copyrine alkaloid from Cleistopholis patens.
Further examination of the active ethanolic extract of the root bark of Cleistopholis patens by using bioassay-directed fractionation resulted in the isolation of a new alkaloid, 3-methoxysampangine (compound I), together with three known alkaloids, eupolauridine (compound II), liriodenine (compound III), and eupolauridine N-oxide (compound IV). The proposed structure of compound I was based on its physicochemical properties and spectral data. 3-Methoxysampangine exhibited significant antifungal activity against Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans. This is the first report of the isolation of liriodenine (compound III) from the root bark of C. patens.
Alkaloids↗
Isolation and growth of adult human epidermal keratinocytes in cell culture. 1978.
Human epidermal keratinocytes may be isolated in high yield from 0.1 mm keratotome sections of adult skin by short-term trypsin release. When plated on a collagen-coated plastic surface or on a collagen gel, keratinocytes attach with high efficiencies (greater than 70%) and form confluent, stratified cultures. Cell populations of predominantly basal cells produce proliferative primary cell cultures while populations of basal cells and malpighian cells result in nonproliferative primary cultures. Both nonproliferative and proliferative primary cultures may be subcultured on collagen gels following dispersion by trypsin and EDTA. Methotrexate strongly inhibits proliferative keratinocytes at low concentrations (0.1 microgram/ml) but has no cytotoxic effect on non-proliferative cells. L-serine and dexamethasone increase the multiplication rate of both primary and subcultured human keratinocytes.
Adult↗
Cyclosporine augments renal mitochondrial function in vivo and reduces renal blood flow.
The in vivo action of cyclosporine A (CS) on rat renal cortical mitochondria was investigated. CS (30 mg.kg-1.day-1) given orally to rats for 30 days caused an augmentation of renal mitochondrial oxidative phosphorylation. The ADP-stimulated respiratory rate was increased by 37.0% with glutamate plus malate as respiratory substrates (P less than 0.025) but not with succinate-supported respiration, indicating enhancement of mitochondrial complex I activity. This reaction may be a response to the 32.5% reduction of renal blood (P less than 0.005) in the CS-treated group, possibly serving to maximize ATP synthesis during ischemia. Ligation-induced decreases in renal blood flow also resulted in enhancement of mitochondrial complex I activity.
Animals↗
[Observation on eosinophilic intranuclear inclusions in hepatocytes of patients with advanced schistosomiasis japonica].
Wedge biopsies of liver from 155 patients with advanced schistosomiasis japonica were observed pathologically, and HBsAg and HBcAg in liver were tested with double bridge peroxidase-anti-peroxidase (PAP) method. 88 of 155 cases (56.8%) were found to be HBsAg and/or HBcAg (HBAg) positive in liver. Eosinophilic intranuclear inclusions were observed in the hepatocytes of 30 cases (19.4%), in which 18 (60%) were also HBAg positive in liver. These inclusions were considered to be the markers of several virus infections, such as cytomegalovirus, herpes simplex virus, etc. The patients with positive HBAg and/or inclusion in liver had significantly more severe pathological changes in liver parenchyma. The results indicate that in addition to hepatitis B, complication with other viral infections in liver, which produce eosinophilic intranuclear inclusion, may also aggravate the pathological changes in liver and may be one of the causes of portal cirrhosis in patients with advanced schistosomiasis japonica (Fig. 1). schistosomiasis japonica
Adolescent↗
Pathogenesis of extrinsic allergic alveolitis and pulmonary fibrosis induced by streptomyces thermohygroscopicus.
There were 48 strains of thermophilic actinomyces isolated from the specimens of mouldy hay and sputum of the patients suffering from farmer's lung (FL). Streptomyces thermohygroscopicus (STHs), one strain of them, was used for this investigation. The microorganisms were injected into the lungs of rabbits and rats by thyrocrico- or tracheocentesis. The results showed that the pathological changes in the lungs including macrophage alveolitis, granuloma formation and diffuse interstitial were similar to that induced by other thermophilic actinomyces. IgG and C3 deposition in the lesions were also observed by immunofluorescence examination. Specific immunocomplexes in the sera of some animals were detected by ELISA with the STH-antisera. The results suggested that STHs was possibly one of the pathogens responsible for FL in China's countryside.
Alveolitis, Extrinsic Allergic↗