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Biomedical subjects

R B Taylor

Publications and source records attributed to R B Taylor.

At least 127 records · Page 7Linked to original sources
PubMed1979

Low avidity as a cause of prozone phenomena.

The incidence of prozones was studied, under various conditions, in a model indirect haemagglutination system and in a radioimmunoassay--both assays depending on the use of anti-immunoglobulin (anti-Ig). It was found that prozones were correlated with the presence of low avidity antibodies, and that these could compete with high avidity antibodies for the limited amount of anti-Ig available. It is proposed that the relatively rapid dissociation of low avidity antibodies allows them to form immune aggregates with the anti-Ig. With increasing size these aggregates would become more susceptible to being washed off. In this way low avidity antibodies could occupy the anti-Ig, and yet be relatively ineffective, either for haemagglutination or for the binding of radioactively labelled (or fluorescein-labelled) anti-Ig to the antigen.

Animals↗
PubMed1979

Hypertensive crisis possibly due to drug interaction.

This report describes a case of possible drug interaction in a patient taking chlorpromazine and guanethidine who experienced a hypertensive crisis following initiation of doxepin therapy. (We have been unable to find a report of a similar interaction at the doses described.) It is advised that physicians exercise caution when contemplating concomitant use of doxepin and guanethidine, even in usually recommended doses.

Blood Pressure↗
PubMed1979

Family behavior modification.

Behavior modification has been effective in dealing with problems in individual patients. The adaptation of behavior modification techniques to the family unit can help to lessen some harmful consequences of adverse human behavior. After identification of the problem and analysis of the stimuli, the behavior and its consequences, stimulus control and contingency management are discussed. A formal written contract, involving all family members and the physician, is useful.

Adolescent↗
PubMed1979

Family: a systems approach.

The family is a social system with elements of structure, bonding, boundaries and function. The person and the dyad are the building blocks (subsystems) of the family. A systems approach allows the family physician to elucidate specific areas of disruption, describe problems in terms of family elements and intervene at the appropriate hierarchic level to promote optimum health to family members.

Adult↗
PubMed1978

Use of HPLC to determine the effect of 17 beta-hydroxy-7 alpha-methylandrost-5-en-3-one (RMI 12,936) on production of progesterone by rat ovarian homogenate.

A new high presure liquid chromatography (HPLC) method for the determination of progesterone in the presence of other delta 43-ketosteroids is described. Using this method it is shown that the rate of production of progesterone from pregn-5-ene-3,20-dione by rat ovarioan homogenate is initally rapid but falls to zero within 10 min. Experiments indicate that the inhibition is due to the progesterone formed. Inclusion of RMI 12,936 with the pregn-5-ene-3,20-dione substrate results in a lower final level of progesterone and continuous production of 7 alpha-methyltestosterone. The reduction in the levels of progesterone in presence of RMI 12,936 corresponds closely to the reduction in plasma progesterone in vivo folowing administration of RMI 12,936 described previously.

Androstenols↗
PubMed1977

Cellular basis of persistent tolerance induced by an aggregate free heterologous immunoglobulin.

Attempts were made to break the tolerance of lymph node B cells to deaggregated human gamma globulin. Using allotype-congenic mice, lymph node cells from virgin or tolerant (5 mg) CBA/Igb donors were transferred tonormal CBA/Iga recipients and the proportion of responding donor B cells estimated 1 and 13 days later. The response of the non-tolerant virgin cells diminished with time but was still detectable at 13 days whereas the response of the tolerant cells was tenfold lower than normal cells at day 1 and was not detectable at 13 days. This functional deletion of tolerant cells was not reversed by enzymatic stripping of the immuno-globulin receptors before transfer, nor by removing T cells-which might have had a suppressor action. In other experiments Igb mice were thymectomized or left as controls at various times before tolerance induction. Lymph node cells from these mice were transferred, together with non-tolerant Iga cells, to irradiated recipients. The cell from tolerant thymectomized donors strongly suppressed the response of non-tolerant cells, whereas the tolerant control cells showed no suppressor activity. It is considered that B-cell tolerance can be maintained by something other than receptor blockade, or active suppression-although the latter can arise in some circumstances.

Animals↗
PubMed1976

Functional half-life of virgin and primed B lymphocytes.

The functional half-life, a measure of the persistence of lymphocytes in an antigen-free environment, has been estimated and found to be about 7 days for virgin 2,4,6-trinitrophenyl (TNP)-reactive mouse B cells, and 2--3 times longer for TNP-primed B cells. Using allotype-congenic mice, lymph node cells were transferred from virgin or primed CBA/Igb donors to normal CBA/Iga recipients, and the proportion of donor B cells estimated at intervals...

Animals↗
PubMed1975

Subclasses of T cells with different sensitivities to cytotoxic antibody in the presence of anesthetics.

When cytotoxic titrations were made of rabbit anti-mouse brain and anti-Thy-1.2 sera against mouse lymphoid cells in the presence of sodium barbital or xylocaine, it was observed that a proportion of T cells were much more sensitive (50 x) than the remainder. This effect could be detected with ethidium or fluorescein diacetate as indicators of cell death, but not with trypan blue or 51Cr. The highly sensitive cells were found in all lymphoid tissues, being most numerous in spleen and least in lymph nodes.

Animals↗
PubMed1975

Permanent hapten-specific tolerance in B lymphocytes.

Tolerance to the hapten TNP was induced in mice congenic with CBA but bearing the Ig-b allotype (Ig-b mice). To induce a high degree of tolerance it was necessary to give five injections of TNP-sulphonate followed by an immunogenic challenge (alum precipitate of TNP-BSA with pertussis adjuvant). Lymph node or spleen cells from these mice were transferred, with or without an equal number of non-tolerant CBA spleen cells, to irradiated CBA recipients and these were challenged with a different TNP-protein conjugate. Anti-TNP antibody bearing the Ig-b allotype was then assayed separately from total anti-TNP, as a measure of the contributions made by tolerant and non-tolerant B-cell populations respectively. Tolerant lymph node cell did not depress the response of normal cells, nor did the normal cells 'break' the tolerance of the Ig-b population even when the latter had been treated with anti-T-cell serum and complement. No response was obtained from tolerant lymph node cells when the recipients were challenged at different time up to 12 weeks after transfer. By this time the control non-tolerant lymph node cells had also lost the capacity to respond. It is concluded that: (1) effectively permanent tolerance, which is not maintained by afferent mechanisms, can be induced in lymph node B cells; (2) B-cell tolerance can be greatly enhanced by immunogenic challenge; (3) spleen may contain a distinct population of B cells which is less susceptible to tolerance; and (4) the life-span of virgin lymph node B cells is probably less than 12 weeks.

Animals↗
PubMed1975

A proposition on the distribution of antibody affinities, with implications for the mechanism of B-cell activation.

For most antisera a linear relationship can be shown between log antigen concentration and the log concentration of antibody required to bind half the available antigen. This paper shows that the slope of this line, s, is related to the distribution of individual antibody clonotypes of different affinity. It is argued that the general form of the distribution approximates to exponential (rather than for example Gaussian) and that this indicates a requirement for some force to be exerted through the antigen-receptor bond in order to activate a B cell. An alternative parameter, A, which gives more weight to high affinity clonotypes, is offered in place of K0 as a measure of the avidity and biological effectiveness of an antiserum.

Animals↗