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Biomedical subjects

D R Webb

Publications and source records attributed to D R Webb.

At least 145 records · Page 8Linked to original sources
PubMed1977

Antigen induced alterations in splenic prostaglandin and cyclic nucleotide levels in NZB mice.

Studies were undertaken in order to determine if NZB mice injected with sheep erythrocyte antigens would respond by showing elevated splenic prostaglandin and cyclic nucleotide levels similar to that observed in normal mice. The results show that young NZB mice can respond to sheep erythrocytes by yielding increased levels of splenic PGF2alpha and cAMP. However, because of increased basal levels of PGF2alpha and cAMP, the net increase observed is lower than that observed with normal mice. In old NZB mice exhibiting signs of disease (splenomegaly) and in which defects in immune competence are known to occur, the injection of SRBC results in in no increase in splenic PGF2alpha levels and a decrease in cAMP levels. These animals also have greatly elevated basal levels of PGF2alpha, cAMP, and cGMP. It is concluded that the cellular immune defect in NZB mice is reflected by their faulty metabolic responses to sRBC. Also, the altered basal levels of PG and cyclic nucleotides may be related to the altered cellular immune competence. The latter conclusion is supported by the reduced capacity of spleen cells from young NZB mice to respond to PGE by increasing cAMP levels and by the lack of an effect of inhibitors of PG synthesis on the immune response to sRBC in both young and old NZB mouse spleen cell cultures.

Aging↗
PubMed1976

Antigen stimulation of prostaglandin synthesis and control of immune responses.

Within 2 min following the intravenous injection of sheep erythrocytes (sRBC) there occurs 20 to 80-fold increase in prostaglandin (PG) F2alpha in the spleen. This burst of synthesis is followed by a slow decline to control levels over the next 1-4 hr. No increase in splenic PGF2alpha levels is observed between 24 and 72 hr after injection. Injection of colloidal carbon results in a small increase, approximately 20% of the increase in PGF2alpha observed with sRBC. The early increase in splenic PGF2alpha levels stimulated by sRBC is also dependent upon thymus-derived (T) cells, since the increase is small or nonexistent in athymic mice and NZB mice. Also, the elevation of splenic PGF2alpha levels is blocked by the administration of indomethacin or Ro 20-5720, both of which block the synthesis of prostglandin. A small increase (2-fold) in PGF2alpha levels occurs in the thymus. A soluble antigen, bovine gamma globulin, stimulated a bimodal increase in splenic PGF2alpha levels, the early peak occurring at 2 hr and the later increase occurring at 48 hr. Using inhibitors of prostaglandin synthesis, it is possible to enhance the appearance of cells forming 19S antibody against sRBC, both in vivo and in vitro. Furthermore, inhibition of prostaglandin synthesis enhances DNA synthesis induced in a two-way mixed-lymphocyte reaction only in whole spleen cell cultures and not in cultures of spleen cells purified by passage over glass wool. Based on this evidence, it is proposed that the prostaglandins represent a major soluble mediator in the control of T cell-T cell interactions and also play an important part in T-B (bone-marrow derived) cell interactions.

Animals↗
PubMed1976

Cancer in a familial IgA deficiency patient: abnormal chromosomes and B lymphocytes.

Two primary cancers were found in a patient with a familial IgA deficiency. Although cytogenetic studies showed nonconsistent pseudodiploid chromosomal pattern in the peripheral blood lymphocyte cultures, there were two metaphases with a deleted short arm of an E (17-18) chromosome and several metaphases with an abnormally large chromosome, larger than chromosome number 1. Also, there were 37 B lymphocytes per mm3 in her peripheral blood which was much lower than other radiation-treated cancer patients. The absence of IgA, the decrease of peripheral B lymphocytes and the chromosomal abnormality might have played a role in her developing the cancers.

Adenocarcinoma↗
PubMed1976

Pulmonary abnormalities in intermediate alpha-1-antitrypsin deficiency.

Pulmonary function studies were carried out in a group of asymptomatic nonsmoking adults with intermediate alpha-1-antitrypsin deficiency who were attending an early disease detection unit in Rochester, N. Y. All subjects were identified by specific protease inhibitor (Pi) typing. Fifteen MZ and 14 MS subjects who had never smoked cigarettes were matched by sex and age to MM controls. Spirometry, static lung volumes, and single breath-diffusing capacity were identical in all Pi type groups with no statistically significant differences noted. Maximal expiratory flow volume curves were obtained in all subjects. MZ subjects demonstrated statistically impaired maximal flow rates at 75%, 50%, and 25% of vital capacity compared to their MM controls. Total pulmonary resistance by the oscillometric method was measured at 3, 5, 7, and 9 cycle/s in the same subjects. Increased frequency dependence of resistance (defined as the difference between total pulmonary resistance at 3 cycle/s and 9 cycle/s) was observed in MZ subjects compared to MM controls. No differences were noted by this method in MS-MM pairs. The data suggest that detectable mechanical abnormalities are present in subjects with the MZ phenotype, even in the absence of established risk factors such as cigarette smoking and high air pollution.

Female↗
PubMed1976

The regulation of the immune response to T-independent antigens by prostaglandins and B cells.

The effect of inhibitors of prostaglandin synthesis on the in vitro primary immune response to two T-independent antigens has been investigated. The results, with PVP or DNP-Ficoll, suggest that the prostaglandins play an important role in the regulation of the immune response to these antigens. Furthermore, it appears that B cells may be involved in their own regulation by synthesizing and responding to prostaglandins. Although it has been previously established that T cells exert a regulatory influence on the response to PVP and DNP-Ficoll, this is the first demonstration of an apparent B cell regulation of B cell function via the production of a specific hormone.

Animals↗
PubMed1975

Antigen-stimulated changes in cyclic nucleotide levels in the mouse.

Mice injected intravenously with sheep erythrocytes (sRBC) demonstrate a transient increase in splenic cAMP levels (4-fold), which peak at 2 min after injection and return to basal levels by 20 min. In addition to the change in cAMP, an increase in splenic cGMP levels (1.5-fold) occurs beginning 5-10 min after sRBC injection, and persists for up to 7 days. During this period cAMP levels remain at or below control levels in the spleen. There is no change in 3':5' cyclic nucleotide levels in the liver and a small increase (1.2- to 1.3-fold) in the thymus at the time when splenic cyclic nucleotide levels are elevated. The changes in splenic cyclic nucleotide levels appear to be dependent on the presence of thymus-derived (T) lymphocytes, since little change occurs in cAMP and changes in cGMP are absent in athymic nude mice. In addition, cAMP levels were increased by pretreatment of normal mice with cortisone acetate, which selects for mature T lymphocytes. Agents that block autonomic nervous system functions have no effect on the early sRBC-induced changes in cyclic nucleotide levels.Indomethacin, an inhibitor of prostaglandin synthesis, reduces the change in cAMP level by 50% and blocks the change in cGMP levels completely. Secondary stimulation with sRBC results in a larger increase in cAMP levels than that seen with a primary injection of sRBC, indicating the presence of specific antigen-sensitive memory cells. Changes in splenic cyclic nucleotide levels cannot be detected at early times after the injection of soluble protein antigens such as bovine serum albumin and keyhole limpet hemocyanin. Salmonella H antigen stimulates a 2-fold increase in cAMP levels, the increase occurring more slowly than with sRBC. The in vivo changes incyclic nucleotide levels are correlated with known changes in cyclic nucleotide levels which have been documented in vitro in both T-cells and T-cell-dependent-B-cell (bone-marrow derived) antibody responses.

Animals↗