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Biomedical subjects

M N Cauchi

Publications and source records attributed to M N Cauchi.

At least 73 records · Page 4Linked to original sources
PubMed1978

Quantitation of globin chains using cellulose acetate electrophoresis: analysis of fetal globin chain production.

A technique involving the quantitative estimation of globin chains using cellulose acetate electrophoresis is described, and applied to the analysis of fetal globin chain production. When cord blood was analyzed, there was poor correlation between the globin chain ratios namely beta/alpha, gamma/alpha and beta/gamma ratios with either age or weight of newborn babies between 36-40 weeks gestation: best correlations were obtained for the beta/gamma ratio against weight (P less than 0.05). However, there was highly significant correlation between the various globin chain ratios and either age or weight of the newborn infant up to 12 weeks of age (P less than 0.001). This technique allows visual demonstration and quantitation of abnormal haemoglobins in a single procedure.

Aging↗
PubMed1978

Some observations on the immunological status in scleroderma (progressive systemic sclerosis).

A variety of tests were performed to determine the immune status of a group of patients with scleroderma (progressive systemic sclerosis). Sera of 11 of 35 patients showed autoantibodies by an immunofluorescent technique. There was no significant difference between the C3 and C4 components of complement in 12 patients tested and laboratory controls. IgM levels were raised in 24 of 34 sera. Four of ten patients showed some deficiency of phagocytic function in the leucocyte iodination test. B cell and T cell numbers were normal in the eight patients tested. Reactivity to mitogens was usually normal in ten patients tested with a deficient response to one of the three mitogens in two patients. In skin reactivity tests in 23 patients, only one was anergic to all of the four antigens tested. It is concluded that although some immune abnormalities are common in scleroderma there is no consistent abnormality in any of the tests used. This does not exclude the possibility that immune factors may be involved in systemic manifestations of the disease, or that there may be some subtle specific abnormality not revealed by the tests performed.

Adult↗
PubMed1978

Osmotic fragility of leukaemic and normal lymphocytes.

The osmotic fragility of cord blood lymphocytes (CBLs), normal adult lymphocytes (NALs) and leukaemic cells was studied using hypotonic saline. Leukaemic cells were more resistant to hypotonic treatment than cord blood or adult lymphocytes. At low hypotonic saline concentrations (less than 0.2% NaCl), almost all of the NALs and CBLs were lysed after thirty minutes at 4 degrees C, whilst a large proportion of chronic lymphatic leukaemia cells remained intact. This phenomenon could conceivably be used to separate tumour cells from normal lymphoid cells.

Adult↗
PubMed1978

Studies by radioiodination of normal adult, fetal and leukemic cell membranes.

A comparison was made between cord blood lymphocytes, normal adult lymphocytes and leukemic cells after membrane iodination with lactoperoxidase. A double-labeling technique using lactoperoxidase iodination with 125I and 131I followed by analysis on polyacrylamide gel electrophoresis revealed a number of membrane differences between leukemic, normal and fetal cells. There was a reduction in the 70,000 molecular weight component in cord blood cells compared to adult lymphocytes, and an increase in membrane peptides with molecular weights of 35,000, 20,000, 9,000 and 4,000. Although smaller molecular weight peptides were also present in chronic lymphatic leukemia as well as acute myeloid leukemia, these were shown to be distinct from fetal type membrane components.

Antigens, Neoplasm↗
PubMed1977

Increased expression of actin-like contractile protein in preneoplastic and neoplastic lesions in rat liver.

Cryostat sections of 16 preneoplastic and 14 neoplastic hepatic lesions induced in rats by 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) were examined by indirect immunofluorescence with human serum containing smooth-muscle antibody (SMA). Preneoplastic lesions showed strong cytoplasmic staining of proliferating oval cells and of the cell outlines of hepatocytes, in areas of nodular hyperplasia. In carcinomas, poorly differentiated hepatocytes showed staining of cell outlines, while well differentiated tumour cells forming glandular structures showed only staining of the luminar surfaces. The stromal cells also showed cytoplasmic staining. Morphologically normal areas of 3'-Me-DAB-treated livers showed weak staining of cell outlines, similar to normal liver. Specificity of the staining reactions was established by failure of staining in parallel control sections treated with normal human serum, or SMA serum neutralized by absorptions with homogenates of smooth muscle or extracts of actin. The results suggest that there is an increased expression of actin-like contractile protein in preneoplastic and poorly differentiated neoplastic liver cells.

Actins↗
PubMed1977

Actin-like contractile protein in carbon tetrachloride-induced cirrhosis in the rat.

Cryostat sections of livers from rats treated with carbon tetrachloride (CCl4) for 12 weeks were examined by indirect immunofluorescence for reactivity with human serum containing smooth muscle antibody (SMA). Increased binding of SMA serum to hepatocytes was observed as early as the first week of CCl4 treatment and remained enhanced during the 12 weeks of study. No difference in staining intensity was observed between pre-cirrhotic liver parenchymal cells and hepatocytes in regenerative nodules of frankly cirrhotic livers. In addition, granulation tissue fibroblasts in cirrhotic livers showed strong reactivity with SMA serum. The specificity of the staining reaction for actin was established by its prevention on neutralization absorptions of the serum with homogenates of smooth muscle or extracts containing actin derived from smooth muscle. Circulating SMA was not demonstrated in the serum of rats at any phase of the study. The observations show that there is an increased expression of actin-like protein in regenerating hepatocytes and granulation tissue fibroblasts in cirrhotic livers.

Actins↗
PubMed1977

Effects of graft-versus-host reaction on inhibition of tumor growth in vivo and on tumor cytotoxicity in vitro.

In DA X Wistar F1 rats, growth of 10(4) Wistar-specific Sp 1 carcinoma cells s.c. was commonly prevented by a mild subclinical graft=versus-host reaction produced by injecting 50 X 10(6) Wistar spleen cells i.p. either concurrently with the tumor or 7 to 14 days previously, Spleen cells alone had no effect on established tumor, but their injection on Day 14 significantly reduced the recurrence rate after excision of tumor on Day 21. In vitro tests in tumor-bearing rats with graft-versus-host reactions showed increased spleen lymphocyte and serum cytotoxicity; these mechanisms may inhibit tumor growth in vivo. Because Wistar lymphocytes and Sp 1 cells are syngeneic, inhibition of tumor cannot be due to allograft rejection but is probably an effect of increased host immunoreactivity during the graft-versus-host reaction.

Animals↗
PubMed1976

Chemoimmunotherapy for maintenance in acute myeloblastic leukemia.

Of 30 adult patients with acute myeloblastic leukemia, 14 achieved complete remission. Eight of these were given chemoimmunotherapy for maintenance. The immunotherapy consisted of intradermal pooled allogeneic leukemic cells (snap-frozen irradiated) and BCG vaccine given by Heaf gun, given twice in 4 weeks. The chemotherapy was given for 1 week in 4 weeks. The median duration of remission in these eight patients was 115+ weeks and the median duration of survival was 147+ weeks. The other six patients who were given chemotherapy only for maintenance had a median duration of remission of 15 weeks and a median survival of 52 weeks. The two groups cannot be compared properly, however, as allocation of patients was not random, and the chemotherapy differed significantly.

Adolescent↗
PubMed1976

Acridine orange fluorescence cytochemistry for detecting lymphocyte immunoreactivity.

Acridine orange staining reveals changes within 3 hours of in vitro stimulation of normal rat lymphocytes with mitogens, and of immune rat lymphocytes with the sensitizing antigen. An increased number of red fluorescent cytoplasmic organelles, presumably lysosomes are seen by fluorescence microscopy. Fluorimetry of the supernatants from stained cell suspensions suggests an overall decreased cell uptake of the dye. The microscopy and fluorimetry detected early events in the reaction of lymphocytes from tumour-bearing rats with the target tumour cells. It would appear that the changes in intracellular behaviour of the dye and in overall cell uptake after immune stimulation are a reflection of dissociated variations in internal and external cell membrane permeability, and may provide simple general means for recognizing cellular immune reactions.

Acridines↗
PubMed1976

Smooth-muscle-associated contractile protein in renal mesenchymal tumour cells and in transformed cells from DMN-injected rats.

Cryostat sections and established in vitro cultures of dimethylnitrosamine(DMN)-induced renal mesenchymal tumours and monolayer cultures of transformed kidney cells derived from rats treated with a carcinogenic dose of DMN were examined by indirect immunofluorescence with human serum containing smooth muscle antibody. Eight mesenchymal tumours examined showed filamentous cytoplasmic staining of spindle cells infiltrating between renal tubules, whilst in normal kidneys interstitial cells were only weakly positive. In established in vitro cultures from 6 mesenchymal tumours, different patterns of staining were observed in morphologically different cell forms, ranging from fine filamentous staining in giant cells to diffuse cytoplasmic fluorescence in small bipolar cells, and cell outline staining in polygonal cells. In addition filamentous staining of microvillous projections and nucleolar staining were observed in some tumour cells. Monolayer cultures of transformed kidney cells showed strong staining of coarse, randomly-orientated cytoplasmic filaments, whilst fibroblasts cultured from normal rat kidney demonstrated an ordered array of fine, parallel filaments. Specificity of the immunofluorescent staining reaction was established by failure to obtain staining with normal serum, with smooth muscle antibody serum neutralized by homogenates of smooth muscle or extracts containing actin derived from smooth muscle. These results indicate that there is an apparent increase of actin-like contractile microfilaments in transformed cells and in renal mesenchymal tumours. The cytoplasmic contracile microfilaments in these cells may play a role in tumour cell mobility and invasion.

Actins↗
PubMed1976

Reaction of human smooth muscle autoantibody with foetal glial cells and their precursors.

Tissue culture monolayers of dissociated human and rat embryonic brains were examined by indirect immunoflurescence with human serum containing smooth muscle antibody. Flat, epithelioid cells showed staining of a fine, filamentous network in the cell body while multipolar cells showed diffuse cytoplasmic fluorescence of the cell body and processes. Both cell types were identified as glial cells by silver stains. Specificity of the immunofluorescent staining reaction was established by failure to obtain staining with normal serum, with smooth muscle antibody serum neutralized by homogenates of smooth muscle or by extracts contining actin-like protein derived from smooth muscle. Reacitivity of of embryonic glial cells with smooth muscle antibody indicates the presence of actin-like proteins which are probably located in cytoplasmic microfilaments.

Animals↗
PubMed1976

Smooth muscle-associated contractile protein in human and experimental acute leukaemias.

Cells from ten human myeloblastic leukaemias and from spontaneous rat myeloblastic and lymphoblastic leukaemias were examined by indirect immunofluorescence with human serum containing smooth muscle antibody. Strong positive cell outline staining of blast cells was seen in cryostat sections of rat leukaemic lymph nodes, spleen and liver. In cell smears of human and rat leukaemias, cell outline fluorescence was restricted to cells in close contact with each other. Membrane immunofluorescence tests of suspensions of viable leukaemic cells were negative. Specificity of the immunofluorescent staining reaction was established by failure to obtain staining with normal serum, or with smooth muscle antibody serum neutralized by homogenates of smooth muscle or extracts containing actin derived from smooth muscle. These observations suggest that smooth muscle-associated microfilaments are present in leukaemic blast cells and that expression of the antigen is dependent on cell-cell contact. The presence of this antigen may facilitate leukaemic infiltration of tissues.

Acute Disease↗
PubMed1976

Binding of thyroid microsomes by lymphocytes from patients with thyroid disease and normal subjects.

Lymphocytes that could bind 125I-labelled thyroid microsomal membranes (ABL) were present in the peripheral blood of patients with various types of thyroid disease as well as in normal healthy subjects. In patients with anti-thyroid cytoplasmic antibodies the number of ABL was about three times normal (11-21 +/- 0-60 compared with 3-26 +/- 0-18 per 10(4) lymphocytes). In contrast, in patients with thyroid disease without anti-thyroid cytoplasmic antibodies, the number of antigen-binding lymphocytes was not significantly greater than in the normal controls (3-94 +/- 0.14 per 10(4) lymphocytes). The binding of thyroid microsomes by antigen-binding lymphocytes could be blocked by thyroid microsomes but not by thyroid mitochondrial membranes, thyroglobulin or liver microsomes.

Autoantibodies↗
PubMed1975

Serum-mediated inhibition of graft-vs.-host reaction.

Rats recovering from a systemic graft-vs.-host reaction (GVHR) possess factors in the serum which can inhibit the production of a local GVHR. After incubation in vitro for 1 h at 37 degrees C these factors reduce the GVH-producing potential of parental spleen or lymph node cells to 24% of control cells treated with normal serum. These factors appear within 1 wk after initiation of a systemic GVHR and some residual activity persists for up to 8 mo. The serum activity was present in the globulin fraction and was completely removed by absorption with spleen, lymph node, or kidney homogenates from either parental strain rats. These studies indicate that during the course of a systemic GVHR, serum factors directed against the host appear in the circulation and tend to inhibit the production of further GVHR by a second challenge of either parental strain cells.

Animals↗
PubMed1975

Non-specific immunological function in acute myeloblastic leukaemia.

Immunological function was investigated in patients with acute myeloblastic leukaemia, both in the untreated stage of the disease and in remission. IgM concentrations were found to be raised in 7 out of 29 patients during the untreated stage. There were only minimal changes in 1gG, 1gA and C' concentrations, and in the incidence of auto-antibodies to normal tissue components. Reactions to standard skin tests were considerably impaired--only 2 out of 10 leukaemic patients in remission responded to 2 or more of these tests. Furthermore the response in leukaemic patients was much weaker than in the corresponding controls. PHA stimulation of lymphocytes from patients in remission showed considerable variation from near normal to gross impairment but a response below 40% of normal was associated with a short remission period, suggesting that PHA stimulation may be a useful indication of the likelihood of relapse.

Acute Disease↗