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Biomedical subjects

R S Tedder

Publications and source records attributed to R S Tedder.

174 records · Page 10Linked to original sources
PubMed1977

Prostaglandins and complement changes in some conditions related to inflammation.

Exposure to ionizing radiation produces several systemic and local reactions which could be mediated by prostaglandins. Prostaglandin levels were therefore studied in blood and tissues of mice which had been exposed to x-rays. Significant increases were found in spleens after 200 to 700 R, and in lungs after 600 to 700 R. These changes were most pronounced 4-7 days after irradiation. Ionizing radiation promptly and potently reduced the activity of prostaglandin dehydrogenase in the spleen, whereas prostaglandin synthesis was less affected. Evidence was obtained for the activation and consumption of haemolytic complement in serum in the course of heart-lung operations involving extracorporeal circulation. Activation involved primarily the classical pathway, and only slightly the alternate pathway.

Animals↗
PubMed1977

A non-invasive test for receptor binding applied to nephrogenic diabetes insipidus.

Studies in animals have determined the importance of specific receptors to the action of many hormones and drugs. In man, a non-invasive external counting technique has been used and absence of receptor function has been demonstrated in a patient with nephrogenic diabetes insipidus using radioactively labelled arginine vasopressin. This is in contrast to the findings in a patient with pituitary diabetes insipidus and a normal control. These results suggest a model for the study of hormone and drug kinetics in man avoiding multiple samplings of biological fluids.

Adult↗
PubMed1976

Changes in intra-vascular complement and anti-treponemal antibody titres preceding the Jarisch-Herxheimer reaction in secondary syphilis.

Six patients with secondary syphilis and one control subject were observed over a period of up to 8 hr following the administration of either penicillin or erythromycin. Serial clinical observations were made and blood samples obtained for complement and serological analysis. The patients showed Jarisch-Herxheimer reactions (JHR) of varying intensity which were found to be preceded by and to parallel in degree certain changes in complement and syphilitic antibody titres. Falls in total haemolytic complement, in C4, C3, C6 and C7 and a marked drop in C1INH were observed. There was no change in total GBG/GGG or evidence of conversion of GBG to GGG. Associated falls occurred in the titres of the QFTA and the QTPHA antibodies but not of the QVDRL or QTPI antibodies. C3 conversion was found in the two patients that suffered severe reactions. Immune complexes were not detected and it is suggested that complement activation occurred in the extra-vascular body compartment. The significance of these changes in relation to other plasma enzyme systems and to the development of the full clinical picture of the JHR is discussed.

Antibodies, Bacterial↗
PubMed1975

Effects on serum complement of normal and pre-eclamptic pregnancy and of oral contraceptives.

The complement system was studied in normal gestation and puerperium, in pre-eclampsia and in women taking oral contraceptives. In 12 normal pregnancies, CH50 titres, C4, C3, C6 and C7 were increased throughout pregnancy; the serum concentration of C1 inhibitor was decreased in the last 2 quarters but greatly raised after delivery. Oral oestrogen-progestogen contraceptives also raised C3 but in contrast to pregnancy lowered CH50, C6 and C7. The different effects of pregnancy and of oral contraceptives may be due to materno-foetal immune reactions. In 9 patients with pre-eclamplsia, complement levels showed a wider scatter and a significantly higher C3 level than in normal pregnancy. Conversion of C3 to C3i was found in 2 of these patients.

Complement C3↗
PubMedDate not supplied

Relationship between expression of hepatitis B virus antigens in isolated hepatocytes and autologous lymphocyte cytotoxicity in patients with chronic hepatitis B virus infection.

Previous studies demonstrated that peripheral blood lymphocytes are cytotoxic to autologous hepatocytes in patients with chronic hepatitis B virus infection. We examined whether cytotoxicity is specifically directed against hepatocytes expressing HBsAg or HBcAg. Viral antigens were detected by immunofluorescence in isolated hepatocytes before and after exposure to T and non-T lymphocytes from 28 patients with chronic HBV infection in an autologous cytotoxicity assay. There was significant reduction in the percentage of HBcAg-positive hepatocytes after exposure to T lymphocytes and, to a lesser extent, after exposure to non-T cells; hepatocytes expressing HBsAg were not affected. Other studies showed that many hepatocytes containing HBcAg have IgG of anti-HBc specificity bound to their nuclei. In the present study, there was significant association between the presence of HBcAg and nuclear IgG in isolated hepatocytes. The ratio between the percentages of HBcAg-positive and IgG-positive hepatocytes (reflecting the proportion of hepatocytes containing free-core antigen) correlated significantly with reduction in HBcAg-positive liver cells after exposure to T cells, but not to non-T cells. These results suggest that hepatocytes in which viral replication is occurring and which express core determinants are susceptible to cell-mediated cytotoxicity and that T-cell cytolysis may be modulated by anti-HBc which is bound to hepatocytes.

Adult↗
PubMedDate not supplied

Differential distribution of hepatitis B core and E antigens in hepatocytes: analysis by monoclonal antibodies.

Current knowledge on the expression of HBeAg in hepatocytes is incomplete because of difficulties in obtaining monospecific antisera devoid of anti-HBc reactivity. In this study, we have examined by immunofluorescence the expression of HBcAg and HBeAg in cryostat liver sections from 25 chronic carriers of HBsAg using monoclonal antibodies. Although virtually all liver biopsies displayed concordance for HBeAg and HBcAg expression, the pattern of fluorescence differed markedly. Thus, monoclonal anti-HBc gave nuclear staining in all 13 reactive biopsies, while cytoplasmic staining was observed in only two of these. In contrast, monoclonal anti-HBe showed cytoplasmic reactivity coexisting with nuclear reactivity in 10 of 13 reactive biopsies. Hepatitis B virus DNA polymerase activity in the serum appeared to correlate better with the presence of HBcAg in hepatocytes rather than HBeAg. These results provide further evidence that HBeAg is expressed both in the nuclei and in the cytoplasm of infected hepatocytes. The observation that the number of cells expressing HBeAg exceeds those expressing HBcAg in carriers with active virus replication would suggest that assembly of core particles occurs in only a proportion of infected hepatocytes expressing HBeAg.

Antibodies, Monoclonal↗
PubMedDate not supplied

Storage and preservation of whole blood samples for use in detection of human immunodeficiency virus type-1 by the polymerase chain reaction.

Methods used in the diagnosis of human immunodeficiency virus type-1 (HIV-1) infection by the polymerase chain reaction (PCR) usually require the separation of lymphocytes from a whole-blood sample within 24 hours of patient sampling. A method is described in which blood samples are mixed with a cryopreservative ('Glycigel'), stored frozen, and DNA suitable for use in an HIV PCR recovered. Samples can be stored at -20 degrees C for up to 3 months and still give positive results with all samples from infected patients; storage at -80 degrees C for at least 3 months shows no loss of titre. The method shows no loss of sensitivity compared to previously described sample preparation methods. Deglycerolised Glycigel supernatants were found to be suitable for conventional anti-HIV-1 serological studies and loss of sensitivity only represented the dilution effect due to sample preparation. Application of the method as a means of storing samples frozen at the point of sampling and transporting them to a central laboratory for processing is demonstrated using samples taken from HIV-1-infected mothers and their babies.

Adult↗
PubMedDate not supplied

Comparison of three immunoassays for the detection of anti-HHV6.

Sera from 96 blood donors were tested for antibody to human herpesvirus 6 by indirect immunofluorescence (IF), circle immunoassay (CIA) and competitive radioimmunoassay (RIA). The correlation between the three assays was good but the CIA and competitive RIA were more sensitive for the detection of HHV6 antibody than indirect IF. The crossreaction of HHV6 antibody with that to the other human herpesviruses was also studied in this blood donor group. No correlation was found between antibody to human herpesvirus 6 by any of the methods described and antibody to any of the other human herpesviruses in these sera.

Antibodies, Viral↗
PubMedDate not supplied

Neutralization of human T-lymphotropic virus type III by sera of AIDS and AIDS-risk patients.

Human T-lymphotropic virus type III (LAV, HTLV-III) is aetiologically linked to acquired immune deficiency syndrome (AIDS) and persistent general lymphadenopathy (PGL). Specific radioimmunoassays (RIA), enzyme-linked assays, immunofluorescence assays (IFA) and immunoblotting techniques are being used widely to detect serum antibodies to HTLV-III in infected patients and in those at risk of infection. However, these assays do not functionally identify those antibodies that neutralize the infectivity of the virus. We have used three methods of titrating serum neutralizing factors: inhibition of syncytium induction, neutralization of envelope pseudotypes of vesicular stomatitis virus (VSV) and reduction of infectivity of HTLV-III for a cell line permissive to virus replication. We report here that sera from subjects in various disease categories possess only low-level neutralizing activity, even when antibodies to viral membrane antigens are present in high titre. Envelope pseudotypes prepared from four HTLV-III isolates made in three different countries are equally sensitive to neutralization by positive sera, including sera from patients yielding two of the virus isolates.

Acquired Immunodeficiency Syndrome↗