Robert M. Galbraith

The extracellular actin-scavenger system and actin toxicity.

ACTIN is the most abundant protein in mammalian cells. Cell motility and change in the size and shape of cells depend on the ability of monomers of actin to polymerize to actin filaments. When acti...

Rheumatic disorders in primary biliary cirrhosis.

Eighty-three patients with primary biliary cirrhosis were investigated to determine the prevalence of rheumatic disorders. 14 had scleroderma, which tended to be mild but in several patients produced severe systemic manifestations. The CRST syndrome (calcinosis, Raynauds phenomenon, sclerodactyly, telangiectasia) was only identified twice. There was an increased incidence of HLA A1+B8 in those patients with scleroderma. As well as those with scleroderma, 4 patients had a destructive arthropathy resembling avascular necrosis. 4 patients had an inflammatory arthritis, without specific features, but the frequency was no greater than might be expected in the general population.

High Prevalence of Seroimmunologic Abnormalities in Relatives of Patients with Active Chronic Hepatitis or Primary Biliary Cirrhosis

Abstract To determine the familial prevalence of serologic abnormalities, immunoglobulin disturbances and biochemical evidence of liver dysfunction, 260 relatives of patients with chronic hepatitis or primary biliary cirrhosis were studied. Mitochondrial, smooth-muscle and nuclear antibodies were more frequent than in controls matched for age and sex. Abnormal immunoglobulin levels occurred in almost half the relatives, and 71 per cent had some immunologic disturbance. In addition, elevated alkaline phosphatase levels and hypergammaglobulinemia were common, the latter being more frequent (p<0.001) in the group with active chronic hepatitis (34 per cent) than in the relatives of patients with primary biliary cirrhosis (9.3 per cent). Furthermore, in three of the 55 families studied, two or more members were found to have cirrhosis. These findings suggest a similar genetic predisposition to immunologic abnormalities among the families of patients with these two diseases, although environmental factors are p...

The human materno-foetal relationship in malaria. II. Histological, ultrastructural and immunopathological studies of the placenta

Histological and ultrastructural studies of four placentae heavily infectd with Plasmodium falciparum revealed large intervillous accumulations of erythrocytes containing parasites together with monocytes which had ingested pigment. These appearances were associated with focal syncytial necrosis, loss of syncytial microvilli and proliferation of cytotrophoblastic cells. In addition, marked irregular thickening of trophoblastic basement membranes and protrusion of tongue-like projections of syncytiotrophoblast into the basement membrane were observed. In six other placentae which contained scanty amounts of pigment but no parasites, representing past or inactive infection, no large collections of monocytes or abnormalities of trophoblast were apparent but basement membrane thickening was evident. Immunohistological studies revealed no significant differences between placentae positive for parasites and those containing pigment only, although the amount of certain immunoproteins and clotting factors was clearly increased above normal. These findings establish that P. falciparum infection in the placenta may result in substantial damage although lesions within the villus are rare. Furthermore, previous infection, although adequately controlled, may leave a heritage of pigment deposition, basement membrane thickening and immunopathological lesions. These results may thus account for both the high frequency of intra-uterine growth retardation and the rarity of congenital malaria in the presence of P. falciparum malaria.

Predicting survival in fulminant hepatic failure using serum Gc protein concentrations.

Plasma Gc protein sequesters actin released into the circulation after massive hepatocyte necrosis, but is greatly depleted in the process. In fulminant hepatic failure (FHF), Gc is present in serum both as a complex with actin and as unbound protein, the latter becoming completely exhausted in those patients with the most severe FHF. In the present study, 47 consecutive patients with FHF, 39 of whom were the result of acetaminophen (AC) overdose, were evaluated to determine whether measurement of Gc protein levels could be used to predict survival. Using serum samples obtained shortly after admission as well as later samples, levels for total Gc protein, percentage of Gc complexed with actin, and calculated unbound Gc remaining in serum were compared for survivors and those who died of their illness. The most marked changes were present in unbound Gc levels in nonsurvivors, the mean of which for follow‐up samples was 10% of normal mean values, as compared with 23% of normal mean values in those who survived (P<.01). Using a cutoff value for unbound Gc protein of ±34 μg/mL to predict survival, outcome was correctly predicted in 32 of 47 (68%) patients using early samples, and in 24 of 27 (89%) patients using later sera. No differences were observed between values and/or outcome in AC and non‐AC cases. Measurement of Gc protein level correctly predicted all patients dying of hepatic failure. This single measurement compares favorably with multifactorial predictive models, such as the Kings College model, and might be a useful test for patients being considered for transplantation. (Hepathology 1995;21:101‐105).

Transferrin binding by human lymphoblastoid cell lines and other transformed cells

Abstract Viable cells of 18 human cell lines, including 15 transformed cell lines of malignant and lymphoblastoid origin, were examined by an indirect immunofluorescence method for their ability to bind purified transferrin and transferrin in normal human serum. The specificity of the reaction was investigated by study of the binding reactions of several other serum proteins, including albumin, α-1-antitrypsin, and α-2-macroglobulin. Membrane binding of human transferrin was demonstrated in less than 5% of normal peripheral blood mononuclear cells or cultured diploid fibroblasts, but in more than 80% of the cells from 13 of the transformed lines, and the data obtained indicated that this binding reaction reflected the presence of specific receptors for transferrin.

Histocompatibility Antigens in Active Chronic Hepatitis and Primary Biliary Cirrhosis

The frequency of antigens HL-A 1 (48%) and HL-A 8 (52%) in 54 patients with active chronic hepatitis from south-east England was significantly higher than in 89 control subjects from the same region (22% and 17% respectively). No correlation could be detected with the age and sex of the patients or with the presence of a particular immunological abnormality but the frequency of HL-A 1 and HL-A 8 was much lower in the nine patients who were positive for HBAg than in the 45 HBAg-negative cases. These results provide further evidence of the importance of genetic factors in active chronic hepatitis. In contrast the frequency of HL-A 1 and HL-A 8 in primary biliary cirrhosis, both in 45 patients from south-east England and in 28 patients from western Scotland, was not significantly different from that found in control groups from the same regions.

Transferrin binding to peripheral blood lymphocytes activated by phytohemagglutinin involves a specific receptor. Ligand interaction.

Immunohistological studies have indicated that membrane sites binding transferrin are present upon activated human peripheral blood lymphocytes. In this study, we have investigated transferrin uptake in human lymphocytes exposed to phytohemagglutinin (PHA), by quantitative radiobinding and immunofluorescence in parallel. In stimulated lymphocytes, binding was maximal after a 30-min incubation, being greatest at 37 degrees C, and greater at 22 degrees C than at 4 degrees C. Although some shedding and endocytosis of transferrin occurred at 22 degrees and 37 degrees C, these factors, and resulting synthesis of new sites, did not affect measurement of binding which was found to be saturable, reversible, and specific for transferrin (K(a) 0.5-2.5 x 10(8) M(-1)). Binding was greater after a 48-h exposure to PHA than after 24 h, and was maximal at 66 h. Sequential Scatchard analysis revealed no significant elevation in affinity of interaction. However, although the total number of receptors increased, the proportion of cells in which binding of ligand was detected immunohistologically increased in parallel, and after appropriate correction, the cellular density of receptors remained relatively constant throughout (60,000-80,000 sites/cell). Increments in binding during the culture period were thus due predominantly to expansion of a population of cells bearing receptors. Similar differences in binding were apparent upon comparison of cells cultured in different doses of PHA, and in unstimulated cells binding was negligible. Transferrin receptors appear, therefore, to be readily detectable only upon lymphocytes that have been activated.

Enhanced antibody responses in active chronic hepatitis: relation to HLA-B8 and HLA-B12 and porto-systemic shunting.

Titres of antibodies to rubella, measles, smooth muscle, nuclei, and Escherichia coli were examined in relation to the presence of particular histocompatibility antigens in 57 patients with active chronic hepatitis, 8 of whom were HBsAg positive. With the exception of antibodies to E. Coli, the HBsAg-negative patients with HLA-B8 or HLA-B12 had higher titres than those with neither, and antibody titres were highest in the 7 cases with both these histocompatibility antigens. In contrast, E. coli antibody titres were not related to the presence of particular histocompatibility antigens but correlated closely with the degree of portosystemic shunting. None of the HBsAg-positive patients possessed HLA-B8, and titres of all the antibodies were significantly lower than in the HBsAg-negative cases. The increased antibody response in HBsAg-negative patients is likely to be due to a genetically determined increase in immunological responsiveness for which HLA-B8 and HLA-B12 are markers. The results obtained in healthy family members also suggest that this defect in immunoregulation is under polygenic control.

Gc (vitamin D binding protein) binds to cytoplasm of all human lymphocytes and is expressed on B-cell membranes☆

Peripheral blood lymphocytes were examined immunohistologically for evidence of interactions with Gc protein, a major vitamin D binding protein in serum. In the cytoplasm, binding sites for purified Gc were readily detectable in all cells, and these sites were only partially occupied by Gc. In contrast, on the membrane of viable cells, there was negligible evidence of binding of either the apo- or holoform of Gc protein, but substantial quantities of firmly bound immunoreactive endogenous Gc were detected. Separation experiments and double-label fluorescence with antisera recognizing defined phenotypic markers showed immunoreactive membrane Gc on 30-40% of unfractionated mononuclear cells and greater than 95% of monocytes or B cells. Only 5-8% of T cells were similarly reactive; these were not apparently confined to any given subset. Extraction of unfractionated cells with 6 M urea or solubilization in Nonidet P-40 released immunoreactive Gc protein, with physicochemical properties indistinguishable from those of Gc purified from serum (apparent MW 56K; pI 4.8-5.1). These findings indicate that membrane Gc may represent another surface immunofluorescence marker for B cells, and may play a role in immunocyte function.