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Biomedical subjects

D L Coleman

Publications and source records attributed to D L Coleman.

At least 55 records · Page 3Linked to original sources
PubMed1990

Interleukin 6 is an autocrine growth factor for mesangial cells.

Interleukin 6 (IL-6) induces the acute phase response, differentiation of B cells, proliferation of T cells, thymocytes, hematopoietic progenitors, hybridoma and plasmacytoma cells. Monocytes, T cells, fibroblasts, epithelial and endothelial cells secrete IL-6. Since IL-6 responsive cell-types may participate in the pathogenesis of glomerular inflammation, we studied the secretion of IL-6 by rat MCs, using the IL-6 dependent hybridoma cell line B9. The results of our studies indicate that MCs secrete IL-6 with a molecular weight of 17-42 kDa and isoelectric point of 4.0 to 5.3 MC-IL-6 activity could be blocked by a polyclonal antimurine-IL-6 antibody. MC express IL-6 mRNA as determined by Northern blot. Furthermore, our data demonstrate that IL-6 acts as an autocrine growth factor for MC. Incubation of subconfluent MC with recombinant IL-6 results in a dose-dependent increase of 3H-thymidine incorporation and number of MCs. Moreover, reverse phase HPLC fractions of MC-CM containing IL-6 activity increase 3H-thymidine incorporation by MC. In addition to its possible paracrine role in mediating the immune response in the glomerulus, MC-IL-6 may also be one of the autocrine signals leading to mesangial cell proliferation in vivo.

Animals↗
PubMed1990

Rat tracheal epithelial cells produce granulocyte/macrophage colony-stimulating factor.

It is unknown whether local resident cells of the upper airway are able to regulate the number and function of phagocytic cells by the secretion of cytokines. We undertook to determine if tracheal epithelial cells (TEC) produce the potent cytokine granulocyte/macrophage colony-stimulating factor (GM-CSF) and how TEC-derived GM-CSF might be regulated. Conditioned media (TEC-CM) from 7- to 21-day-old primary cultures of rat TEC contained material with bioactivity similar to GM-CSF. This bioactivity was increased in conditioned medium from lipopolysaccharide (LPS)-treated (1 microgram/ml) TEC. Molecular characterization of bioactivity revealed a molecular weight of 27 to 44 kD by gel-filtration high performance liquid chromatography (HPLC), and elution at 44 to 50% acetonitrile by reverse-phase HPLC, similar to that of authentic GM-CSF. The biologic activity of TEC-CM was completely blocked by a goat polyclonal anti-GM-CSF antibody. With in situ hybridization using a murine GM-CSF cDNA probe, more than 95% of the adherent TEC population expressed GM-CSF transcripts, and the number of transcripts was significantly increased by LPS (1 microgram/ml, 48 h). TEC appear to produce a cytokine that is functionally, biochemically, and antigenically indistinguishable from GM-CSF. The ability of TEC to produce GM-CSF suggests that these cells may play a role in modulating the inflammatory response in the airway.

Animals↗
PubMed1990

Effect of diet on incidence of diabetes in nonobese diabetic mice.

Nonobese diabetic/Lt mice exhibit a diabetes incidence greater than 70% in females at 30 wk of age. In studies designed to see whether increased dietary carbohydrate, fat, or protein influenced the severity or age at onset of the syndrome, we fed semipurified AIN-76 diet adulterated with increased amounts of these ingredients. Surprisingly, all AIN-76-based diets greatly reduced the expected incidence of diabetes at 30 wk. In addition, a hypoallergenic infant formula, Pregestimil, containing casein hydrolysate in place of protein, completely prevented diabetes up to 1 yr of age. To assess how dietary components might modulate the diabetes incidence, we adulterated standard AIN-76 diet with skim milk, gluten, brewer's yeast, or a natural-ingredient rodent open-formula mouse diet (Old Guilford 96 [OG96]. No increase in diabetes incidence was seen with skim milk (10%) or wheat gluten (10%), whereas brewer's yeast (10%) and OG96 (25%) added to AIN-76 increased the incidence compared to mice fed OG96 only. The diabetogenic factor or factors in OG96 could be extracted by chloroform plus methanol (2:1), leaving little activity in the residue. We conclude that diet is a critical factor in diabetes development and that unknown chloroform-methanol-soluble substances in natural-ingredient chow not found in semipurified diets can enhance the development of diabetes in genetically susceptible mice.

Aging↗
PubMed1989

Recombinant granulocyte-macrophage colony-stimulating factor increases adenylate cyclase activity in murine peritoneal macrophages.

Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotrophic cytokine which stimulates the function and proliferation of macrophage populations. Although the effects of GM-CSF are diverse and GM-CSF has entered into clinical trials, relatively little is known about signal transduction pathways utilized by GM-CSF. In view of previous studies which have suggested that some of the effects of GM-CSF on monocyte-macrophages can be mimicked by agents which increase intracellular cAMP, we investigated the effect of rGM-CSF on adenylate cyclase (AC) activity in murine peritoneal macrophages. Adenylate cyclase activity was quantitated in macrophage membrane preparations and in intact cells. In seven separate experiments, GM-CSF (50 U/ml) increased AC activity by 61(6)% relative to macrophages treated with carrier medium alone. A dose-dependent increase in AC activity was observed (10 to 100 U/ml) which peaked within 1 to 5 min after the addition of GM-CSF and returned to basal levels by 10 to 20 min. Lineweaver-Burk analysis revealed that the Vmax of macrophage AC was increased from 0.40 to 0.52 pmoles cAMP/min by GM-CSF but the Km was unchanged. Intracellular cAMP was increased by GM-CSF to 129(27)% of control values by 1 min of treatment (n = 6). Under similar experimental conditions, GM-CSF did not increase the activity of PK C (n = 14) or phospholipase A2 (n = 3) in peritoneal macrophages. These data show that macrophage adenylate cyclase activity is rapidly stimulated by GM-CSF. Moreover, these findings support further study of the role of cAMP in transmitting the intracellular signals initiated by GM-CSF in tissue macrophages.

Adenylyl Cyclases↗
PubMed1989

In vitro percutaneous absorption and stratum corneum binding of alachlor: effect of formulation dilution with water.

The effect of vehicle dilution on the percutaneous absorption of alachlor, 2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide, through excised human skin was determined using flowthrough design glass penetration cells and 14C radiotracer methodology. Three dilutions of alachlor (in the solubilizing commercial formulation) with distilled water were utilized: 1:20, 1:40, and 1:80 (v/v); corresponding to concentrations of 23.0, 11.8, and 5.98 mg alachlor per milliliter, respectively. Skin from the penetration studies and human powdered stratum corneum from the binding studies demonstrated a high capacity for alachlor. A soap and water (1:1, v/v) solution effectively decontaminated powdered stratum corneum. Using plasma as the receptor solution, penetration ranged from 0.5 to 4% of the applied dose for an 8-hr exposure period. Lag times of 1.2 to 1.8 hr were observed. Increasing dilution resulted in significant enhancement (p less than 0.01) in the rate and extent of alachlor penetration. Although the biological significance of this observation is unclear, this phenomenon might be explored in future studies because of its ramifications for human toxicity and for decontamination opportunities.

Acetamides↗
PubMed1989

Osteotropic agents induce the differential secretion of granulocyte-macrophage colony-stimulating factor by the osteoblast cell line MC3T3-E1.

Osteoblasts play a central role in the regulation of bone remodeling. Not only are they responsible for the formation of new bone, but they also regulate bone resorption. These cells also exert regulatory influences outside the bone in that they are able to regulate hematopoiesis. However, obtaining pure populations of osteoblasts devoid of contaminating cell types remains problematic. One approach to this problem is the use of cloned osteoblastic cell lines. To this end we have used MC3T3-E1, a cloned murine osteoblast cell line of C57BL/6 origin. We report that MC3T3-E1 cells respond to lipopolysaccharide (LPS) and, to a lesser extent, parathyroid hormone (PTH) by the secretion of granulocyte-macrophage colony-stimulating factor (GM-CSF). However, 1,25-(OH)2D3, a potent activator of osteoblasts, fails to induce these cells to secrete GM-CSF. These results suggest that MC3T3-E1 cells respond to osteotropic agents in a hierarchical fashion. Secretion of GM-CSF is not constitutive but rather requires active induction of the cells. MC3T3 cells fail to secrete detectable levels of interleukin-2 (IL-2), IL-3, or IL-4, regardless of whether or not the cells are activated. The data indicate that MC3T3-E1 cells secrete cytokines in response to osteotropic agents in a way similar to that of normal primary osteoblasts. Therefore, MC3T3-E1 cells may serve as a good in vitro model for primary osteoblasts.

Alkaline Phosphatase↗
PubMed1989

Partial characterization of a low-molecular-weight, macrophage-derived inhibitor of DNA synthesis: a possible immunoregulatory molecule.

It has been previously reported that tumor-associated macrophages isolated after combination therapy contained an activity that inhibited thymocyte proliferation in the IL-1 comitogenic assay. The present report shows that this macrophage-derived inhibitory factor (MDIF) inhibits DNA synthesis in diverse adherent and nonadherent cells in vitro. The elution pattern seen after chromatography using Bio-Gel P10 or Sephadex G-25 columns indicated a molecular size of 3-6.5 kDa. However, full activity was retained when MDIF was passed through an Amicon filtration membrane having a cut off of 500 Da. It was also seen that other molecules less than 500 Da, such as thymidine, thimerosal, and PGE2, each of which was also shown to be growth inhibitory, eluted in a size range similar to that of MDIF after chromatographic separation. Ion exchange chromatography confirmed that MDIF was distinct from thymidine, and a radioimmunoassay indicated that PGE2 was not responsible for MDIF activity. Little or no inhibitory activity could be detected in macrophages isolated from progressing tumors or from tumors excised after cyclophosphamide treatment of tumor bearers. Given that this inhibitory activity was associated with macrophages derived from tumors induced to regress by combination therapy, the possibility is discussed that MDIF may play an important role during the regulation of immune reactions at the tumor site.

Adjuvants, Immunologic↗
PubMed1989

Clinical evaluation of a Raman scattering multiple gas analyzer for the operating room.

A Raman spectrometer multiple gas analyzer was used to monitor inspired and expired concentrations of oxygen (O2), nitrogen (N2), carbon dioxide (CO2), nitrous oxide (N2O), halothane, and isoflurane in 10 patients. The Raman spectrometer and a dedicated mass spectrometer were connected to each patient to provide a comparison of the two instruments. Results show that readings from the Raman spectrometer are within 0.62 vol% of known gas standards for O2, N2, N2O; within 0.03 vol% for CO2; and within 0.04 vol% for halothane, enflurane and isoflurane. Clinical results show that Raman spectrometer readings are within 1.36 vol% of the mass spectrometer readings for O2, N2, N2O; within 0.01 vol% for CO2; and within 0.22 vol% for halothane and isoflurane. The clinical and laboratory results indicate the Raman spectrometer monitors airway gases and vapors as accurately as a dedicated mass spectrometer.

Anesthesiology↗
PubMed1989

Rat mesangial cells produce granulocyte-macrophage colony-stimulating factor.

Because inflammatory processes in renal glomeruli may involve monocyte-macrophages (MPs) and T-lymphocytes, we have investigated whether products of glomerular mesangial cells (MCs) can stimulate the proliferative activity of these effector cells. We found that cultured rat MCs (subcultures 2-15), maintained under serum-free conditions, secrete a soluble factor into the supernate [MC-conditioned medium (CM)], which supports growth of the T-helper cell-derived line HT-2. Moreover, MC-CM increased [3H]thymidine incorporation by thioglycollate-elicited peritoneal MPs but did not induce growth of the interleukin 2 (IL-2)- or interleukin 4 (IL-4)-dependent cell line CTLL-2. Further functional, serological, and biochemical analysis of MC-CM revealed that rat MCs secrete a cytokine that, by all of the techniques used, is indistinguishable from granulocyte-macrophage colony-stimulating factor (GM-CSF). Both northern blot and in situ hybridization with a specific cDNA probe for murine GM-CSF showed that MCs express GM-CSF mRNA transcripts. The present findings indicate that cultured rat MCs produce GM-CSF. Release of GM-CSF by MCs in vivo may play a role in the interaction of MCs with MPs, T-cells, and neutrophils in glomerular disease.

Animals↗
PubMed1989

Parathyroid hormone and lipopolysaccharide induce murine osteoblast-like cells to secrete a cytokine indistinguishable from granulocyte-macrophage colony-stimulating factor.

Osteoblasts are the cells responsible for the secretion of collagen and ultimately the formation of new bone. These cells have also been shown to regulate osteoclast activity by the secretion of cytokines, which remain to be defined. In an attempt to identify these unknown cytokines, we have induced primary murine osteoblasts with two bone active agents, parathyroid hormone (PTH) and lipopolysaccharide (LPS) and analyzed the conditioned media (CM) for the presence of specific cytokines. Analysis of the CM was accomplished by functional, biochemical, and serological techniques. The data indicate that both PTH and LPS are capable of inducing the osteoblasts to secrete a cytokine, which by all of the techniques used, is indistinguishable from granulocyte-macrophage colony-stimulating factor (GM-CSF). Secretion of GM-CSF is not constitutive and requires active induction. Production of the cytokine is dependent on the dose of PTH or LPS added. It has been demonstrated that the addition of GM-CSF to bone marrow cultures results in the formation of increased numbers of osteoclasts. Therefore, these data suggest that osteoblasts not only participate in bone remodeling by formation of new matrix but may regulate osteoclast activity indirectly by their ability to regulate hematopoiesis.

Animals↗
PubMed1989

The influence of genetic background on the expression of mutations at the diabetes locus in the mouse. V. Interaction between the db gene and hepatic sex steroid sulfotransferases correlates with gender-dependent susceptibility to hyperglycemia.

Steroid sulfurylation represents a potential mechanism for controlling the level of active steroids within a tissue. We have elucidated an inbred strain background-dependent interaction between the diabetes (db) mutation and steroid sulfotransferase (ST) enzymes, potentially modulating the level of active steroid hormones or their precursors in the liver. Gonadectomized mutants were analyzed to correlate how strain- and gender-dependent variation in ST activities interacted with db to achieve diabetogenesis. Both sexes on the C57BL/KsChp (BKs) background developed severe early-onset hyperglycemia, and gonadectomy failed to prevent diabetes. In contrast, C3HeB/FeChp (C3HeB)-db/db males, but not females, were diabetes susceptible, and the male susceptibility was completely dependent upon endogenous testes-derived testosterone. The female resistance, in turn, was dependent upon ovarian sex steroids. The differential requirements of BKs- and C3HeB-db/db males and females for gonadal sex steroids could be explained on the basis of the differential strength of the interaction between the db mutation and hepatic ST activities. Hepatic ST from normal adult females sulfurylated dehydroepiandrosterone (DHEA), whereas this activity disappeared in cytosols of normal adult males by 8 weeks of age. This sexually dimorphic inability to sulfurylate (pre)androgens was controlled by testosterone. Diabetogenic susceptibility in BKs mutant mice of both sexes was associated with marked depression of preandrogen/androgen sulfurylation [female mutants exhibiting at least a 5-fold reduced DHEA sulfurylation at a near-physiological concentration (0.2 microM)]. This reduced preandrogen/androgen sulfurylation occurred concomitant with a 10-fold acceleration of estrone (E1) sulfurylation at a limiting (0.2 microM) concentration, essentially producing a hyperandrogenized hepatic tissue state. These extreme shifts in ST substrate preferences were not observed in the diabetes-resistant C3HeB-db/db females. Kinetic analysis of semipurified hepatic ST from BKs-db/db females showed a 10-fold decrease in Km for E1 (apparent Km = 0.9 microM in mutants vs. 9.0 microM in normals). Whereas the Km for DHEA did not differ from the control value, hepatic ST from BKs-db/db females showed a 10-fold decreased maximal velocity for DHEA sulfurylation (1230 vs. 12750 pmol/mg.h in control preparations). The antihyperglycemic effects of dietary E1 therapy were associated with enhanced androgen sulfurylation in BKs-db/db females and restoration of androgen sulfurylation in BKs-db/db males.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1989

Assessment of routine chest roentgenograms and the physical examination to confirm endotracheal tube position.

We consecutively and prospectively studied 219 critically ill patients to evaluate the accuracy of the physical examination in assessing ETT position and the appropriateness of taking routine chest x-ray films after intubation in the ICU. As a result of x-ray findings, 14 percent of the patients required ETT repositioning, and 5 percent had main-stem intubations. Endobronchial intubation was more common in females than in males, and frequently occurred after emergency intubations. Sixty percent of the main-stem intubations occurred despite the presence of equal breath sounds on examination. Techniques to minimize the risk of tube malposition, such as cuff ballottement in the suprasternal notch and referencing the ETT centimeter markings, were not completely reliable. This study confirms the unreliability of the physical examination to assess ETT position. Chest x-ray films after intubation are indicated to verify tube position, particularly after emergency intubations. Other techniques such as use of a lighted stylet require evaluation to determine whether they are more cost-effective in verifying ETT placement in patients who have no other indication for postintubation x-ray films.

Cost-Benefit Analysis↗