PubMed Health⌕ Search

Biomedical subjects

J D McCurdy

Publications and source records attributed to J D McCurdy.

15 recordsLinked to original sources
PubMed2001

Toll-like receptor 4-mediated activation of murine mast cells.

Toll-like receptors (TLRs) are a family of pattern recognition receptors that are critical for cellular responses to a variety of bacterial, viral, and fungal products. Mast cells are important to host survival in a number of models of bacterial infection and might act as sentinel cells in host defense. We therefore examined the expression of TLRs and associated molecules by murine bone marrow-derived mast cells (BMMCs). BMMCs and the murine mast cell line MC/9 expressed mRNA for TLR2, TLR4, and TLR6 but not TLR5 and for both adapter molecule MD-2 and signaling molecule MyD88 but lacked surface CD14. After activation with the TLR2- and TLR4-dependent stimuli Staphylococcus aureus-derived peptidoglycan and Escherichia coli-derived lipopolysaccharide (LPS), respectively, mast cells produced significant levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha). To determine whether mast cells require TLR4 for cellular responses to LPS, mast cells were derived from the bone marrow cells of C3H/HeJ and C57Bl/10ScNCr mice containing a point mutation and a null mutation, respectively, in TLR4. Using these models, we demonstrated that the BMMC IL-6 and TNF-alpha responses to LPS were completely dependent on functional TLR4 with no significant LPS response observed in its absence. These findings have important implications for the mechanism of mast cell responses to pathogens and their products and suggest that different TLR4-expressing cells might have different thresholds for activation with LPS.

Animals↗
PubMed1985

Effect of adroxazine, a heterocyclic compound of the adrenals, on the rate of replication of lymphoblastoid cells.

It has been found that the addition of 10(-2)-10(-8) microL/mL of adroxazine, heterocyclic compound of the adrenals, to the tissue culture medium increases the rate at which three strains of lymphoblastoid cells replicate. For example, the addition of 10(-5) micrograms/mL of adroxazine to cultured L5178Y cells decreases their doubling time from approximately 11 to 8 h and addition of 10(-3) micrograms/mL of adroxazine to the tissue culture medium of Huly-16 or Huly-29 cells decreases their doubling time from approximately 43 to 34 and 36 h, respectively. Other concentrations of adroxazine, from 10(-2) to 10(-8) micrograms/mL, cause a less but measurable decrease in doubling time. The effect of adroxazine on the rate of incorporation of [3H]thymidine into acid-precipitable material by lymphoblastoid cells was found to parallel the effect of adroxazine on doubling time. The effect of adroxazine on the length of DNA synthesis and mitosis was calculated from the percent of cells that are labeled with [3H]thymidine during a 20-min interval and the percent of cells in mitosis, respectively. Results showed that adroxazine does not decrease the length of DNA synthesis or mitosis, but markedly decreases the sum of pre- and post-mitotic resting times (TG2 + TG1). Addition of 10(-3) micrograms/mL of adroxazine to the medium decreases the resting times of Huly-16 cells from approximately 20 to 10 h and Huly-29 cells from approximately 12 to 5 h. Addition of 10(-5) micrograms/mL of adroxazine to the medium decreases the resting time of L5178Y cells from 3.3 to 0.1 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1984

Association of leucogenenol, a thymothyroid hormone, with carrier proteins in the thymus.

Leucogenenol a heterocyclic enolic thymothyroid hormone (MW 383) whose concentration in the serum regulates the rate at which already committed cells of the bone marrow develop into functional cells, was found to be associated in the thymus with a carrier protein. The carrier protein for leucogenenol is not precipitated by heating to 80 degrees but following this treatment leucogenenol is precipitated in association with proteins precipitated by acetone and then by saturated ammonium sulfate. On chromatography on Sephacryl G-200 it was found that leucogenenol was associated with proteins of MW approximately 38,000. Leucogenenol is not eluted from the chromatographic column if it is not associated with its carrier proteins. It is suggested that other hormones such as those associated with the reproductive cycle or compounds that result from tissue damage induce the liberation of leucogenenol from its carrier protein in the thymus to the circulation where it is associated as previously described, with a protein of approximately MW 300,000.

Animals↗
PubMed1984

Effect of leucogenenol, a thymothyroid hormone, on the growth of immature and neonatally thymectomized rats.

The reports of early investigators that growth is delayed by thymectomy of immature animals have been confirmed. Although growth is delayed by thymectomy, thymectomized animals approach asymptotically with age the same final weight as corresponding intact animals. Treatment with leucogenenol, a thymothyroid hormone, accelerates the rate of growth of immature neonatally thymectomized rats to that of normal rats. However, treatment with leucogenenol does not increase the rate of growth of normal rats. Treatment with leucogenenol does not change levels of growth hormone (GH) or thyroxine (T4) in the serum of either thymectomized or intact immature and adult rats. Neither is the depression in levels of serum leucogenenol that follows thymectomy associated with a change in serum levels of GH or T4. Thus it is apparent that levels of serum leucogenenol do not affect the rate of growth of immature animals by increasing serum levels of GH or T4. By analogy with the finding that treatment with leucogenenol increases the rate at which committed cells of the bone marrow and cells involved in the immune response develop into functional cells, it is suggested that the levels of serum leucogenenol are one of the factors that determine the rate at which types of body cells that make up bone and other body tissues develop from committed precursors.

Animals↗
PubMed1982

Effect of leucogenenol, a thymothyroid hormone, on allograft rejection and hemolysin formation.

Recent investigations in this laboratory have established that daily treatment with leucogenenol, an enolic heterocyclic hormone synthesized by the thymus and/or thyroid, induces neonatally thymectomized mice that have accepted a skin allograft to reject this allograft in 7 to 14 days. Also, daily treatment with leucogenenol causes neonatally thymectomized mice to respond to challenge with sheep erythrocytes with the formation of normal titers of hemolysin. These results demonstrate that the hormone leucogenenol induces the development of those cells, absent in neonatally thymectomized mice, that are necessary for a normal immune response.

Animals↗
PubMed1981

Effect of tumors on the concentration of leucogenenol in the serum of mice.

It was found that inoculation of several strains of mice with several types of tumor cells resulted, within 24 hr, in a significant decrease in the serum leucogenenol levels of the mice. Serum leucogenenol levels of the mice inoculated with tumors that are rejected become normal or temporarily above normal at approximately the time the tumor is observed to be rejected. Contrariwise, serum leucogenenol levels of mice inoculated with tumors that are not rejected remain at significantly lower than normal levels during the life of the mice. Unlike tumors, skin allografts increase serum leucogenenol levels. When tumors are rejected because of the previous immunization of the mice, serum leucogenenol levels become normal at approximately the time the tumor is observed to be rejected. Excision of the tumor after 1 week of growth, with the consequent recovery of the mice, is accompanied by a recovery of normal serum leucogenenol levels. Also, it was found that injection of mice with a cell-free 0.9% NaCl solution extract of a tumor results in a temporary decrease in serum leucogenenol levels comparable to that observed with the inoculation of a viable tumor which lasts from 24 to 96 hr. It is suggested that the suppression of serum leucogenenol levels is one of the factors responsible for the immunosuppression associated with a growing tumor.

Animals↗
PubMed1980

Leucogenenol a thymothyroid hormone.

Thymectomy and, to a lesser extent, thyroidectomy cause a significant decrease in the serum leucogenenol levels of rats. Daily injections of neonatally thymectomized mice with leucogenenol causes the mice to maintain a normal level of neutrophils and lymphocytes in their circulation. The thymus and thyroid are the only tissues in rats and mice that afford radioactive leucogenenol when incubated in a medium containing radioactive D-glucose. It is concluded that the thymus and possibly the thyroid are responsible for the normal biosynthesis of leucogenenol in animals.

Adrenal Glands↗