Biomedical subjects

K A Kelly

Publications and source records attributed to K A Kelly.

At least 19 recordsLinked to original sources

PubMed2001

Prediction of retention in micellar electrokinetic chromatography from solute structure. 1. Sodium dodecyl sulfate micelles.

Like other chromatographic techniques, retention factor, k, in micellar electrokinetic chromatography (MEKC) is directly related to solute partition coefficient and the chromatographic phase ratio as k = Kphi. Unlike conventional chromatography, however, the phase ratio and partition coefficient can be accurately determined in MEKC for a given micellar pseudostationary phase. This means that retention factor in MEKC can be predicted for solutes with known micelle-water partition coefficients without any prior experimentation. In this paper, the use of this simple relationship for prediction of retention behavior in MEKC is examined. The principle of additivity of functional group contribution to partitioning is used to calculate the micelle-water partition coefficient, Kmw, for SDS micellar pseudophase. The micellar substituent constants for 20 functional groups (training set) were determined. Using these substituent constants, the Kmw and retention factors for a group of 80 neutral solutes (test set) were predicted. The linear plot of predicted versus observed log k had an R2 = 0.97 and a slope equal to 1.01. It is shown that the retention times (thus chromatograms) in MEKC can be predicted from the calculated retention factors after only one initial experiment to measure teo and t(mc) under the experimental conditions.

Journal Article↗

PubMed2001

Chlamydia trachomatis infection induces mucosal addressin cell adhesion molecule-1 and vascular cell adhesion molecule-1, providing an immunologic link between the fallopian tube and other mucosal tissues.

The development of a protective vaccine against the sexually transmitted disease caused by Chlamydia trachomatis may prevent complications associated with insidious infection. Vaccination via the vaginal route may not be practical, and other routes should be investigated. To this end, the adhesion molecules induced on the fallopian tube endothelium during infection with C. trachomatis were characterized. Adhesion molecules were identified in fallopian tube biopsy specimens cultured with 5 x 10(6) infection-forming units of C. trachomatis serovar E. Frozen sections were prepared from these tissues and were stained by immunohistochemical techniques. Infection with live, but not UV-inactivated, C. trachomatis induced a significant increase in levels of vascular cell adhesion molecule-1 and the mucosal addressin cell adhesion molecule-1 but not of other adhesion molecules. Therefore, infection with C. trachomatis induces adhesion molecules that are associated with other mucosal tissues and inflammatory sites, which suggests that mucosal routes of immunization may be effective.

Biopsy↗

PubMed2001

Dendritic cells derived from multiple myeloma patients efficiently internalize different classes of myeloma protein.

Myeloma protein is a unique tumor antigen that can be used to devise tumor-specific vaccination strategies. As dendritic cells (DCs) are extremely potent at inducing T-cell responses, clinical protocols have been designed using myeloma protein-pulsed DCs to elicit anti-tumor cell responses in vivo. To optimize antigen pulsing of DCs, we investigated mechanisms of antigen uptake and evaluated various laboratory parameters including class of myeloma protein, antigen exposure time, and DC maturational stage.DCs were generated by culturing peripheral blood stem cells from myeloma patients in granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). Myeloma proteins were labeled with fluorescein isothiocyanate (FITC) and internalization of protein by DCs was measured by flow cytometry.IgG, IgA, and free-kappa light chain myeloma proteins were all rapidly internalized by DCs in a time-dependent fashion. Maturation of DCs with tumor necrosis factor-alpha (TNF-alpha) resulted in diminished uptake. Endocytosis of myeloma protein by DCs was primarily mediated by fluid-phase macropinocytosis based on morphology, nonsaturable uptake kinetics, and sensitivity to drugs that inhibit membrane ruffling. Pulse-chase experiments revealed that the majority of internalized myeloma protein disappeared within 4 hours but was retained in the presence of chloroquine, indicating antigen processing had occurred. Cultured DCs from myeloma patients are functional and can efficiently endocytose different classes of myeloma protein by the mechanism of macropinocytosis. This demonstrates the feasibility of using all classes of myeloma protein for producing DC vaccines, and defines culture conditions for optimizing antigen loading of DCs for induction of anti-myeloma responses.

Antigen Presentation↗

PubMed2001

Chlamydia trachomatis infection does not enhance local cellular immunity against concurrent Candida vaginal infection.

Although Th1-type cell-mediated immunity (CMI) is the predominant host defense mechanism against mucosal Candida albicans infection, CMI against a vaginal C. albicans infection in mice is limited at the vaginal mucosa despite a strong Candida-specific Th1-type response in the draining lymph nodes. In contrast, Th1-type CMI is highly effective against an experimental Chlamydia trachomatis genital tract infection. This study demonstrated through two independent designs that a concurrent Candida and Chlamydia infection could not accelerate or modulate the anti-Candida CMI response. Together, these results suggest that host responses to these genital tract infections are independent and not influenced by the presence of the other.

Animals↗

PubMed2001

Tetrahydrobiopterin levels regulate endothelial cell proliferation.

Vascular abnormalities, including altered angiogenesis, are major factors contributing to the morbidity and mortality of diabetes. We hypothesized that impaired angiogenesis in diabetes results from decreased tetrahydrobiopterin (BH4)-dependent synthesis of nitric oxide (NO) by endothelial cells (EC). To test this hypothesis, we utilized EC from spontaneously diabetic BB (BBd) and nondiabetes-prone BB (BBn) rats to investigate the link between BH4 and EC proliferation. There were significant decreases in the proliferation rate and expression of proliferating cell nuclear antigen in BBd versus BBn EC, with no evidence of apoptosis in either group. Sepiapterin (a precursor of BH4 via the salvage pathway) increased BH4 synthesis and enhanced proliferation of BBd EC. The stimulating effect of sepiapterin on EC proliferation was attenuated by NG-monomethyl-L-arginine, a NO synthase inhibitor. Reducing BH4 concentrations in BBn EC caused a decrease in proliferation, which was attenuated by a long-acting NO donor. Our results suggest that BH4 levels regulate proliferation of normal EC and that a BH4 deficiency impairs NO-dependent proliferation of BBd EC.

Animals↗

PubMed2001

Characteristics and evolution of extraintestinal manifestations associated with ulcerative colitis after proctocolectomy.

AIMS: Describe the characteristics of extraintestinal manifestations complicating ulcerative colitis present preoperatively and determine their evolution after surgery. METHODS: Between 1976 and 1986, 281 patients with ulcerative colitis exhibiting one or more extraintestinal manifestations (EIM) before either IPAA (n = 147), Brooke ileostomy (n = 71), Kock pouch (n = 48) or ileorectostomy (n = 15) were assessed retrospectively. The clinical evolution of each manifestation was classified as having disappeared, improved, remained unchanged or aggravated postoperatively. An efficacy index was designed to assess the ratio of the number of cases cured or improved over the number of cases unchanged or aggravated. The relationship between EIM and gender, age, duration of disease and the type of surgery was also ascertained. RESULTS: 433 EIM were observed in 281 patients. The most common were arthralgias of the large joints (n = 146), of the sacroiliac joint (n = 59) and the small joints (n = 51). In comparison to patients without EIM having received the same operation during the same period of time, EIM were seen more often in women, younger patients, than those with longer duration of disease and the ileoanal anastomosis group. 60% had only one EIM at a time. Based on the efficacy index, thromboembolic accidents and erythema nodosum were the most commonly cured or improved. Ocular manifestations and primary sclerosing cholangitis were unaffected. The other EIM responded favorably but variably with improvement in two thirds of patients. The presence of a rectal remnant (IRA) or ileal reservoir did not affect the evolution of the EIM. CONCLUSIONS: Thromboembolic complications which are life-threatening, erythema nodosum and arthralgia of the small and large joints which impair quality of life, benefited the most from proctocolectomy. Those conditions may be considered preoperatively when making the decision for surgery.

Adult↗

PubMed2001

Development of dendritic cells in culture from human and murine thymic precursor cells.

The earliest T-precursor population in the adult murine thymus can give rise to dendritic cells (DC) in culture if stimulated with a cocktail of cytokines that includes interleukin (IL)-3, but not with cytokine mixes based on granulocyte-macrophage colony stimulating factor (GM-CSF), normally used to generate myeloid-derived DC. This and other evidence led to the proposal that two different lineages of DC exist, one lymphoid-related and the other myeloid-related. To determine whether this selective response to cytokines was restricted to murine DC, early human thymic T-precursors were isolated and their capacity to generate DC in response to various cytokines directly compared to their murine counterparts. In contrast to cultures of murine thymic precursors, CD34+CD1a- lineage marker negative (Lin-) precursor cells from the human thymus proliferated and generated DC with both the IL-3-containing cytokine mix lacking GM-CSF and with GM-CSF based cytokine mixes. These CD34+CD1a-Lin- human precursor cells also gave rise to NK cells under appropriate culture conditions, but produced no granulocyte, monocyte, eosinophil, megakaryocyte or erythroid cells in standard soft-agar colony-forming cell assays. Thus, although apparently lymphoid-restricted, the human thymic DC precursors responded to the myeloid factor GM-CSF as well as to the cytokines selective for murine lymphoid-related DC.

Animals↗

PubMed2000

Glucosamine inhibits inducible nitric oxide synthesis.

Glucosamine is widely used in Europe for treatment of arthritis in humans. Based on recent findings that excess production of nitric oxide (NO) by inducible NO synthase (iNOS) mediates the pathogenesis of arthritis, we hypothesized that glucosamine may inhibit NO synthesis. To test this hypothesis, we used an in vivo rat model of lipopolysaccharide (LPS)-induced inflammation. Intravenous administration of d-glucosamine (0.5 mmol/kg) 6 h before, at the time of, and 6 h after intraperitoneal LPS injection (1 mg/kg) decreased urinary excretion of nitrate by 31 and 48%, respectively, at days 1 and 2 post LPS administration. When cultured macrophages were treated with LPS (1 microg/ml) to induce iNOS expression, addition of 0.1, 0.5, 1, and 2 mM d-glucosamine decreased NO production by 18, 38, 60, and 89%, respectively. Glucosamine had no effect on cellular arginine, NADPH or tetrahydrobiopterin concentrations, but dose-dependently suppressed iNOS protein expression. Similar decreases in iNOS protein occurred in spleen, lung, and peritoneal macrophages of glucosamine-treated rats. These studies demonstrate that glucosamine is a novel inhibitor of inducible NO synthesis via inhibition of iNOS protein expression, and provide a biochemical basis for the use of glucosamine in treating chronic inflammatory diseases such as arthritis.

Animals↗

PubMed2000

Modulation of tumor angiogenesis by stem cell factor.

Mast cells accumulate within solid tumors and can release many angiogenic factors, suggesting that they may modulate vascularization of tumors. Stem cell factor (SCF) stimulates mast cell migration, proliferation, and degranulation and therefore may influence mast cell behavior within tumors. We investigated the contribution of SCF to tumor angiogenesis by manipulating its level in mammary tumors. Sense or antisense cDNA fragments of rat SCF were ligated into an episomal expression vector. Ethylnitrosourea-induced rat mammary tumor cell lines were transfected with vector containing either control (no insert, C-P), sense (S-P), or antisense (AS-P) SCF DNA. The functional nature of the transfectants was confirmed by measuring SCF in cell lysates and conditioned media. Immunohistochemical analysis of the tumors induced in Berlin-Druckrey rats by these transfected cells demonstrated that mast cell number and microvascular density were significantly higher in S-P tumors and significantly lower in AS-P tumors, compared with C-P tumors. The expression of von Willebrand factor, an endothelial cell marker, showed a similar pattern. AS-P tumors were significantly smaller than either C-P or S-P tumors. These data suggest that SCF modulates tumor growth and angiogenesis via the involvement of mast cells.

Animals↗

PubMed2000

Impaired nitric oxide production in coronary endothelial cells of the spontaneously diabetic BB rat is due to tetrahydrobiopterin deficiency.

Endothelial cells (EC) from diabetic BioBreeding (BB) rats have an impaired ability to produce NO. This deficiency is not due to a defect in the constitutive isoform of NO synthase in EC (ecNOS) or alterations in intracellular calcium, calmodulin, NADPH or arginine levels. Instead, ecNOS cannot produce sufficient NO because of a deficiency in tetrahydrobiopterin (BH(4)), a cofactor necessary for enzyme activity. EC from diabetic rats exhibited only 12% of the BH(4) levels found in EC from normal animals or diabetes-prone animals which did not develop disease. As a result, NO synthesis by EC of diabetic rats was only 18% of that for normal animals. Increasing BH(4) levels with sepiapterin increased NO production, suggesting that BH(4) deficiency is a metabolic basis for impaired endothelial NO synthesis in diabetic BB rats. This deficiency is due to decreased activity of GTP-cyclohydrolase I, the first and rate-limiting enzyme in the de novo biosynthesis of BH(4). GTP-cyclohydrolase activity was low because of a decreased expression of the protein in the diabetic cells.

Animals↗

PubMed2000

Collodion baby: a case report.

A case report of a collodion baby born in a community hospital who was diagnosed, stabilized, and transferred for dermatologic management is presented. Differential diagnosis based on cornification disorder phenotypes is outlined. The initial stabilization, management, and nursing considerations of the infant with impaired barrier function of the skin are outlined.

Follow-Up Studies↗

PubMed2000

Characterization of the binding site for a novel class of noncompetitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonists.

The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor is an ionotropic glutamate receptor that mediates fast excitatory synaptic transmission throughout the central nervous system. In addition to the glutamate binding site, allosteric modulatory sites on the receptor are inferred from the ability of synthetic compounds to affect channel function without interaction with the glutamate binding site. We have identified a novel class of potent, noncompetitive AMPA receptor antagonists typified by CP-465, 022 and CP-526,427. The latter compound was radiolabeled and used to elucidate the pharmacology of one allosteric modulatory site. [(3)H]CP-526,427 labels a single binding site in rat forebrain membranes with a K(d) value of 3.3 nM and a B(max) of 7.0 pmol/mg of protein. The [(3)H]CP-526,427 binding site does not seem to interact directly with the glutamate binding site but overlaps with that for another class of AMPA receptor antagonists, the 2,3-benzodiazepines. This binding site is distinct from that for the antagonist Evans blue and for several classes of compounds that modulate AMPA receptor desensitization. These results indicate the existence of at least two physically distinct allosteric sites on the AMPA receptor through which channel activity or desensitization is modulated.

Animals↗

PubMed2000

Expression of mucosal homing receptor alpha4beta7 is associated with enhanced migration to the Chlamydia-infected murine genital mucosa in vivo.

The CD4 T helper cell type 1 (Th1) response is essential for the resolution of chlamydial genital infection in mice. However, not all Th1 clones are equally protective in eradicating the infection. Since oral immunization regimens produce protective immunity, we evaluated the role of the mucosa-associated homing receptor, alpha4beta7, in trafficking to the genital mucosa. Using a panel of CD4, Th1 cell lines and clones, we compared the lymphocyte homing patterns of a Chlamydia-specific, protective clone (P-MoPn), a nonprotective clone (N-MoPn), and a keyhole limpet hemocyanin (KLH)-specific cell line (KLH-1). T cells were labeled with the fluorescent dye PKH-26, adoptively transferred into Chlamydia-infected mice, and monitored at different time points throughout the course of a genital infection. We found that clones P-MoPn and N-MoPn migrated to similar extents to the genital tract and in significantly greater numbers than the KLH-specific T-cell line. Both clones and the KLH-1 line expressed similar levels of the adhesion molecules alpha4, beta1, CD44, and CD11a. However, clones P-MoPn and N-MoPn expressed higher levels of the mucosal homing receptor, alpha4beta7. Also, clones P-MoPn and N-MoPn but not the KLH-1 line migrated to the mesenteric lymph node, suggesting a mucosal recirculation pattern. Moreover, blocking alpha4beta7 adhesion interaction in vivo significantly reduced the recruitment of P-MoPn but not KLH-1 to the genital tract. These findings show that the mucosal homing receptor alpha4beta7 is utilized by a subset of CD4 cells during migration to the Chlamydia-infected genital tract.

Animals↗

PubMed2000

Differential regulation of CD4 lymphocyte recruitment between the upper and lower regions of the genital tract during Chlamydia trachomatis infection.

Genital infection with Chlamydia trachomatis results in both the local recruitment of protective immune responses and an inflammatory infiltrate that may also participate in tubal pathology. As a beginning to understanding the etiology of immune system-mediated tubal pathology, we evaluated the regional recruitment of lymphocyte subsets to different areas of the female genital tract (GT) over the course of a murine infection with the mouse pneumonitis agent of Chlamydia trachomatis (MoPn). Using flow cytometric techniques we found that the CD4 lymphocyte subset was preferentially recruited to the upper GT (oviduct and uterine horn) over the lower GT (cervical-vaginal region) throughout the course of MoPn infection. The influx of CD4 cells also correlated with the expression of endothelial cell adhesion molecules (ECAMs) and in vitro lymphocyte adherence in the upper GT. Interestingly, the expression of ECAMs in the lower GT was not maintained longer than 7 days after infection, even in the presence of viable chlamydiae. Taken together, these data suggest that regulatory mechanisms of lymphocyte recruitment differ between the upper and lower regions of the GT and may influence the clearance of chlamydiae and the development of tubal pathology.

Animals↗

PubMed2000

Characterization of lymphocyte response in the female genital tract during ascending Chlamydial genital infection in the guinea pig model.

It is well known that pathology caused by chlamydial infection is associated closely with the host response to the organism and that both innate and adaptive host responses contribute to tissue damage. While it is likely that the organism itself initiates the acute inflammatory response by eliciting cytokine and chemokine production from the host cell, the adaptive response is the result of activation of the cell-mediated immune response. While there are several studies describing the nature of the pathologic response in primate, guinea pig, and murine models, there is less information on the kinetics of the CD4 and CD8 response following primary and challenge infections. In this study, we have quantified by flow cytometry the mononuclear cell response to genital infection with the agent of guinea pig inclusion conjunctivitis in the cervix, endometrium, and oviducts at various times following a primary intravaginal infection and after a challenge infection. Tissues from individual animals were assessed for cells expressing CD4, CD8, or Mac-1 and for B cells. Peak responses of each subset occurred 10 to 14 days after a primary infection. The number of Mac-1-expressing cells in each tissue site was found to be dependent on the size of the inoculating dose of chlamydiae. The responses of each cell type were generally stronger in the cervix than in the upper genital tract. In contrast to the murine model but consistent with the primate models, there were equal numbers of CD4 and CD8 cells present in the infiltrates. Twenty-one days after challenge infection, which was performed 50 days after the primary infection, there was a significant increase in the number of CD4, CD8, and B cells in the oviduct compared to the number of these cells at the same time after a primary infection, providing clear cellular evidence for a cell-mediated immune pathologic response.

Animals↗

PubMed2000

Synergistic effects of clinically achievable concentrations of 12-O-tetradecanoylphorbol-13-acetate in combination with all-trans retinoic acid, 1alpha,25-dihydroxyvitamin D3, and sodium butyrate on differentiation in HL-60 cells.

Our recent studies demonstrated that 12-O-tetradecanoylphorbol-13-acetate (TPA) has pharmacological activity for the treatment of acute myelocytic leukemia patients. In the present study, we investigated the potential synergistic effect of all-trans retinoic acid (RA), 1alpha,25-dihydroxyvitamin D3 (VD3), and sodium butyrate (NaB) on TPA-induced differentiation in HL-60 human promyelocytic leukemia cells. The cells were treated once with these agents for 48 h or treated every 24 h for 96 h. Treatment of HL-60 cells once with TPA, RA, VD3, or NaB for 48 h resulted in concentration-dependent growth inhibition and cell differentiation. At clinically achievable concentrations, TPA (0.16 nM) increased the number of adherent cells and RA (0.1-1 microM) increased the number of nitroblue tetrazolium (NBT)-positive cells. The combinations of TPA (0.16 nM) with RA (0.1-1 microM), VD3 (1 nM), or NaB (100 microM) for 48 h synergistically increased differentiation as measured by the formation of adherent cells (P < or = 0.01). Moreover, cells treated with various combinations of low concentrations of TPA, RA, VD3, and NaB every 24 h for 96 h resulted in a further decrease in cell growth and an increase in differentiation. At clinically achievable concentrations, the strongest stimulation of differentiation was achieved in cells treated with a "cocktail" that combined TPA, RA, VD3, and NaB. The synergistic effect of combinations of TPA with RA or NaB at clinically effective concentrations on HL-60 cell differentiation suggests that the combination of these agents may improve the therapeutic efficacy of TPA for the treatment of acute promyelocytic leukemia (APL) patients. A differentiation "cocktail" that combines TPA, RA, VD3, and NaB may provide an even more effective strategy for improving the therapeutic efficacy of TPA and RA.

Anesthetics, Intravenous↗

PubMed1999

Human follicular dendritic cells inhibit superantigen-induced T-cell proliferation by distinct mechanisms.

Follicular dendritic cells (FDCs) reside within germinal centers of secondary lymphoid tissue where they play a critical role in antigen-driven immune responses. FDCs express numerous adhesion molecules that facilitate cellular interactions with B and T cells within the germinal center microenvironment. Although human FDCs have been shown to influence B-cell development, very little is known about the ability of FDCs to regulate T-cell responses. To investigate this functional aspect of FDCs, highly enriched preparations were isolated by magnetic cell separation using the FDC-restricted monoclonal antibody HJ2. We found that isolated human FDCs inhibited proliferation of both autologous and allogeneic T cells, and were dependent on the number of FDCs present. Inhibition by FDCs was observed using two serologically distinct superantigens at multiple concentrations (Staphylococcus enterotoxin A and B). In contrast, B cells failed to inhibit, and often augmented superantigen-induced T-cell proliferation. Antibody-blocking studies showed that CD54 and CD106 were involved in the ability of FDC to inhibit T-cell proliferative responses. When FDCs and T cells were separated by a semipermeable membrane, the inhibitory effect was partially abrogated, demonstrating that in addition to cell-cell interactions, a soluble factor(s) was also involved in the process. The addition of indomethicin to cultures improved the proliferative response in the presence of FDCs, indicating that inhibition was mediated, in part, by prostaglandins. These results indicate that FDCs regulate T-cell proliferation by two molecular mechanisms and that FDC:T-cell interactions may play a pivotal role in germinal center development.

Antigen Presentation↗

PubMed1999

[The physiology of intestinal pouches].

To summarize, J-shaped and W-shaped ileal pouches serve as adequate neorectal reservoirs after proctocolectomy. These pouches anastomosed directly to the anal canal are as distensible and capacious and as readily evacuated as the rectum in health. However, the use of S- or H-shaped ileal pouches, which have efferent limbs positioned between the pouch and the anal canal, sometimes leads to outflow obstruction and incomplete evacuation. There is little doubt that neorectums made of ileum can allow patients to have entirely "normal" patterns of fecal continence. Nonetheless, with pouch distension, large-amplitude, propulsive pouch contractions occur. These large pressure waves bring on the urge to defecate. They stress the anal sphincters more acutely than either the infrequent, small-amplitude, nonpropulsive contractions or clustered contractions of the healthy rectum. Nonetheless, patients learn to recognize the different signals heralding the impending need for evacuation from the ileal pouch and deal with them. Jejunal pouches, because of their greater distensibility and larger capacity, and the greater frequency of interdigestive migrating myoelectric complexes (MMCs) occurring in them, hold the promise of being a better rectal substitute than ileal pouches. They are more difficult to construct, however. Colonic pouches, when anastomosed to the anal canal after rectal resection, also act as adequate fecal reservoirs. Their main drawback is the inability of some patients to empty them. Small (5 cm) colonic pouches seem to empty better than larger (10-15 cm) ones. Jejunal pouches and colonic segments used as gastric substitutes after gastrectomy provide a better reservoir for ingested food than straight jejunal segments. The main drawback of the pouches is their inability to triturate the solid content of a meal and to regulate the rate of its emptying into the small intestine. Liquids and solids likely empty from these pouches at the same rate, in contrast to the slower emptying rate of solids from the healthy stomach. This likely leads to maldigestion of solids, perhaps contributing to the weight loss often found after gastrectomy.

Colorectal Neoplasms↗