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J Hughes

Publications and source records attributed to J Hughes.

At least 163 records · Page 9Linked to original sources
PubMed1999

Role of Fas (CD95) in tubulointerstitial disease induced by unilateral ureteric obstruction.

Murine renal tubular epithelial cells and interstitial fibroblasts may express both Fas (CD95) death receptor and Fas ligand and are vulnerable to Fas-mediated death in vitro. We therefore hypothesized that an absence of renal Fas may protect resident cells from undergoing apoptosis. We performed unilateral ureteric ligation [producing unilateral ureteral obstruction (UUO)] in 6-wk-old normal control mice and C57Bl6/lpr mice, which express a nonfunctional Fas receptor. Obstructed kidneys were removed at days 3, 7, and 14 (n = 6 per group). Tubular cell apoptosis at day 7 was significantly reduced in lpr mice [21.8 +/- 5.8 vs. 45.7 +/- 7.6 cells/10 high-power fields (hpf), P < 0.02]. Importantly, there was no difference in tubular cell proliferation between normal and lpr mice at any time point studied. Interestingly, double labeling with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) and the proximal tubule-specific antibody Fx1A indicated that the absence of Fas reduced distal but not proximal tubular death at day 7. In addition, there was no difference in interstitial cell apoptosis or proliferation, suggesting that Fas does not play a significant role in interstitial cell death. Importantly, inflammatory macrophage infiltration and ultimate collagen I deposition was unchanged in lpr mice. In conclusion, the absence of functional cell surface Fas in UUO provides distal tubular cells with partial protection from apoptosis but does not affect interstitial cell fate in this model of tubulointerstitial injury.

Animals↗
PubMed1999

Cyclin kinase inhibitor p21CIP1/WAF1 limits interstitial cell proliferation following ureteric obstruction.

Tubulointerstitial renal injury induced by unilateral ureteric obstruction (UUO) is characterized by marked cell proliferation and apoptosis. Proliferation requires cell cycle transit that is positively regulated by cyclins and cyclin-dependent kinases (CDKs) and inhibited by the CIP/KIP family of cyclin-dependent kinase inhibitors (CKIs: p21, p27, and p57). We have shown that the absence of p27 results in markedly increased tubular epithelial cell proliferation and apoptosis following UUO (V. Ophascharoensuk, M. L. Fero, J. Hughes, J. M. Roberts, and S. J. Shankland. Nat. Med. 4: 575-580, 1998). Since p21 mRNA is upregulated following UUO, we hypothesized that p21 would also serve to limit cell proliferation and apoptosis. We performed UUO in p21 +/+ and p21 -/- mice. Cell proliferation [bromodeoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA)], apoptosis [terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method], interstitial myofibroblast accumulation (actin), macrophage infiltration (F4/80), and collagen I expression were quantified at days 3, 7, and 14. In contrast to p27 -/- mice, there was no difference in tubular epithelial cell proliferation or apoptosis between p21 -/- and p21 +/+ mice at any time point. However, interstitial cell proliferation at day 3 was significantly increased in p21 -/- mice [BrdU, 40.7 +/- 1.9 cells/high-power field (cells/hpf) vs. 28.8 +/- 2, P < 0.005], although, interestingly, no difference was seen in interstitial cell apoptosis. Actin/BrdU double staining demonstrated increased interstitial myofibroblast proliferation at day 3 in p21 -/- animals (10 +/- 0.12 vs. 5.8 +/- 0. 11 cells/hpf, P < 0.05), which was followed by increased myofibroblast accumulation at day 7 in p21 -/- mice. No differences were detected in interstitial macrophage infiltration, collagen I deposition or transforming growth factor-beta1 mRNA (in situ hybridization) expression. In conclusion p21, unlike p27, is not essential for the regulation of tubular epithelial cell proliferation and apoptosis following UUO, but p21 levels do serve to limit the magnitude of the early myofibroblast proliferation. This study demonstrates a differential role for the CKI p21 and p27 in this model.

Animals↗
PubMed1999

MRSA: the antipodean experience.

Drug resistant pathogens are becoming an increasing problem affecting paediatric patients requiring strict adherence to infection control hygiene measures to prevent transmission to susceptible patients. Strategies utilised within three paediatric hospitals in Australia are considered and compared with the situation in the United Kingdom. Networking with other infection control teams at other hospitals world-wide enables prompt sharing information and new developments. The author presents the findings of an infection control travel award to Australia.

Australia↗
PubMed1999

Treatment of invasive thymoma with single-agent ifosfamide.

PURPOSE: To evaluate single-agent ifosfamide in the treatment of invasive thymoma. PATIENTS AND METHODS: Fifteen patients (eight male and seven female) with histologically confirmed invasive thymoma were treated. The median age was 48 years (range, 23 to 76 years). Four patients had stage III disease, seven patients had stage IVa disease, and four patients had stage IVb disease. The most common histologic type was lymphoepithelial. Seven patients had received prior treatment, including one patient who received chemotherapy. Ifosfamide 1.5 g/m(2) was given on days 1 to 5, with mesna as a uroprotector. RESULTS: Thirteen patients were assessable for response. Five complete responses (38.5%; 95% confidence interval [CI], 17.7% to 64.5%) and one partial response (7.7%; 95% CI, 1.4% to 33.3%) were seen. The median duration of complete response was 66+ months (range, 25 to 87 months), and the estimated survival rate 5 years after ifosfamide treatment was 57% (SE, 32% to 79%). The most frequent toxicities were nausea, vomiting, and leucopenia, but these were well tolerated. CONCLUSION: Single-agent ifosfamide possesses significant activity against invasive thymoma and is comparable to currently used combination regimens. The inclusion of ifosfamide in combination therapy, particularly in place of cyclophosphamide in regimens such as cisplatin, doxorubicin, and cyclophosphamide, needs to be evaluated.

Adult↗
PubMed1999

Corticotropin-releasing factor type 1 and type 2alpha receptors regulate phosphorylation of calcium/cyclic adenosine 3',5'-monophosphate response element-binding protein and activation of p42/p44 mitogen-activated protein kinase.

CRF exerts a key neuroregulatory control on the function of the hypothalamic-pituitary-adrenal axis. These effects are thought to be mediated primarily through activation of Gs-coupled plasma membrane receptors. In the present study, we investigated the effects of activation of CRF receptors by sauvagine on signaling pathways that converge on phosphorylation of the transcription factor calcium/cAMP response element-binding protein (CREB). Studies were undertaken using CHO cell lines transfected with either rat CRF-1 or CRF-2alpha receptors. Signaling pathways were investigated using immunocytochemical, Western blot, and imaging techniques. Treatment with sauvagine increased phosphorylation of p42/p44, but not of p38 or stress-activated protein kinase (SAPK)/JUN N-terminal kinase (JNK) mitogen-activated protein (MAP) kinases correlating with increased p42/p44 MAP kinase activity. Mobilization of intracellular Ca2+ stores was observed in cells treated with high concentrations (100 nM, 1 microM) of sauvagine. A time- and dose-dependent increase in phosphorylation of the transcription factor CREB was observed in cultures treated with sauvagine. Phosphorylation of CREB occurred at lower concentrations of sauvagine than those required to mobilize intracellular calcium stores, and phosphorylation was not blocked by the mitogen-activated protein kinase kinase inhibitor PD98059 at a concentration (1 microM) that fully inhibited phosphorylation of MAP kinase. Cotreatment of cultures with the protein kinase A inhibitor H89 (10 microM) blocked fully the stimulatory actions of sauvagine (0.1 nM, 1 nM) on phosphorylation of CREB, but not those on phosphorylation of MAP kinase. Phosphorylation of MAP kinase was partially blocked by the phosphoinositide 3-kinase inhibitor LY294002 (5 microM) and by the phosphoinositide-phospholipase C inhibitor U73122 (10 microM). These data demonstrate that cAMP-, Ca2+-, and MAP kinase-dependent signaling pathways are activated by stimulation of CRF-1 and CRF-2alpha receptors. However, in these cells, only protein kinase A-dependent pathways contribute significantly to enhanced phosphorylation of CREB. These represent the first reported observations of CRF receptor-mediated phosphorylation of the transcription factor CREB and activation of MAP kinase signal transduction pathways.

Amphibian Proteins↗
PubMed1999

Experience using radio frequency laptops to access the electronic medical record in exam rooms.

Kaiser Permanente, Northwest, evaluated the use of laptop computers to access our existing comprehensive Electronic Medical Record in exam rooms via a wireless radiofrequency (RF) network. Eleven of 22 clinicians who were offered the laptops successfully adopted their use in the exam room. These clinicians were able to increase their exam room time with the patient by almost 4 minutes (25%), apparently without lengthening their overall work day. Patient response to exam room computing was overwhelmingly positive. The RF network response time was similar to the hardwired network. Problems cited by some laptop users and many of the eleven non-adopters included battery issues, different equipment layout and function, and inadequate training. IT support needs for the RF laptops were two to four times greater than for hardwired desktops. Addressing the reliability and training issues should increase clinician acceptance, making a successful general roll-out for exam room computing more likely.

Computer Communication Networks↗
PubMed1999

Positive moves.

Explore the source record for details and available documents.

Adolescent↗
PubMed1999

Morphological and biochemical modifications of human macrophages treated with various biomaterials.

Although tissue culture techniques are used extensively to explore the biocompatibility of various biomaterials used in orthopaedic, dental and pharmaceutical fields, the role of these materials towards human monocytes/macrophages has not been fully elucidated. The specific objectives of this investigation were: (1) to determine the biochemical markers resulting from exposure of the human monocytes/macrophages to titanium (TI), large size polyethylene (LSP), submicron polyethylene (SPE), hydroxyapatite (HA), large particle size tricalcium phosphate (LTCP), and small particle size tricalcium phosphate (STCP), and (2) to morphologically evaluate the viability of the cells treated with the aforementioned biomaterials. Approximately 15 volunteers donated blood for each phase (24, 48, and 72 hours) of the experiment. The monocytes were isolated by following established lab procedures (Histopaque 1077 and 1119). Aseptic techniques were followed throughout each phase. Each phase contained four experimental groups (TI, LSP, SPE, HA). Each group was comprised of six wells. The total protein, catalase, LDH, MDA, and cell count were measured using established lab protocols. Data obtained suggests that: (I) regardless of the biomaterial being used all experimental groups experienced remarkable phagocytosis in the first two phases (24, 48 hours), (II) during the 24 hour phase MDA activities were increased in TI, LTCP, and STCP treated wells when compared to the control and other experimental groups, (III) in the 48 hour phase the MDA level increased in LPE and STCP treated cells, (IV) there were significant differences in LDH levels in LPE, STCP, and SPE at 24 hours compared to the control and other experimental groups, (V) LDH activities were increased in LPE, STCP, SPE, and LTCP at 48 hours, and (VI) at 72 hours there were significant increases in catalase activity in HA, TI, SPE and LPE when compared to the control group and other experimental groups. Information obtained from this study provided new ideas about the interrelationship of various biomaterials, the effect of size and cell response to the various biomaterials.

Biocompatible Materials↗
PubMed1999

Biochemical markers evaluation of RAW transformed cells during treatment with various biomaterials.

Upon introduction into the human body, biomaterials initially trigger a foreign-body inflammatory response. Furthermore, the wear debris associated with such materials as those used for orthopedic implants, artificial heart valves, and dental implants can cause the body to mount an inflammatory response. This involves the production of phagocytic macrophages that ingest the foreign material while simultaneously producing cytokines that serve as chemotactic agents for an amplified immune response. Currently titanium (Ti), polyethylene (PE), tricalcium phosphate (TCP) and hydroxyapatite (HA) are widely used as biomaterials in medical implants, and particle size is an important factor in the development of orthopedic, dental, and medical implants. The objective of this study was to investigate the effect of various biomaterials (Ti, mixed particle size polyethylene (MPE), ultra high molecular weight polyethylene (UHMWPE), mixed particle size TCP (MTCP), < 0.38 micron TCP (S-TCP), and hydroxyapatite (HA)) on the inflammatory reactions expressed by transformed RAW macrophages. RAW transformed monocytes were obtained from the American Cell Culture Line, (Rockville, MD). The cells were allowed to incubate in contact with the materials for intervals of 24, 48, and 72 hours. Biochemical tests and morphological evaluations were performed after each time point, including screening for cell number, cell protein levels, supernatant protein levels, lactate dehydrogenase (LDH), Maliondialdehyde (MDA), catalase by following standard lab protocols.

Biocompatible Materials↗
PubMed1999

Non-specific immunohistochemical responses in surgical tissue collected from total joint arthroplasty.

Tissues retrieved during revision arthroplasty (n = 25) were processed for routine immunohistochemical techniques to localize the presence of bone resorbing cytokines (IL-1, TNF alpha, and IL-6), and to identify areas of significant necrosis and metallic deposition. Tissues were processed and embedded according to standard laboratory techniques. Several tissue sections were prepared for each sample collected. Several sequential slides were used to demonstrate a thorough histopathological evaluation. Other slides of the same tissues were processed for immunohistochemical evaluation specifically for the localization of cytokines. To identify specific cytokine reactions, antibodies against cytokines were added in working dilutions overnight. Another set of slides were incubated overnight with nonspecific protein and served as negative controls. At the end of the incubation period, all slides were washed in buffer and a second antibody conjugated with peroxidase was added to both sets of slides for one hour. The slides were developed for peroxidase activity. The results revealed that there were several locations on the tissues that appeared highly reactive for cytokines. However, some of these areas turned out to be nonspecific when compared with negative controls and the Hematoxylin and Eosin stained slides. Areas of extreme necrosis or where metal debris was present demonstrated sites of nonspecific reactivity. Areas of necrosis have a high nonspecific affinity for antibodies and these areas of necrosis can be demonstrated on the Hematoxylin and Eosin sections, and were avoided in determining the amount of specific cellular reactivity. The results of this study strongly suggest that the aforementioned factors must be carefully controlled in determining true cellular responses that causes resorption of bone and eventually implant failure.

Arthroplasty, Replacement↗
PubMed1999

The effect of polymer coating biomaterials individually and incombination on the behavior of transformed RAW macrophage cells.

The use of homopolymers as coatings for biomaterials has received much attention in the last decade. However, the modifications and alterations induced by using such materials towards inflammatory cells have not been fully investigated. The specific objectives of this study were to investigate the role of hetero and homopolymers of amino acids on cell proliferation, and to determine the biochemical behavior associated with the incubation of RAW cells with various polymers. The RAW macrophage cell line was obtained from the American Type Culture Collection (Rockville, MD) and maintained in sterile media (RPMI) supplemented with 10% fetal bovine serum and 1% antibiotics and antimycotics. The cells were plated at a density of 1 x 10(6) cells/ml onto 24 well plates. The plates were divided into four groups of six wells per group per phase (24, 48, and 72 hours). Cells in the first group were treated with RGD, cells in group II were treated with poly-L-lysine, group III cells were treated with RGD + poly-L-lysine, and cells in group IV were treated with media alone, and served as controls. Cell number, as well as, protein, MDA, lactate dehydrogenase (LDH), and cytochrome C (cyto C) were determined at the end of 24, 48 and 72 hours. Data obtained from this investigation revealed that: (I) there were no significant difference in total cell counts between all experimental groups and control at the end of the 48 hour phase. However, at 24 hours there were fewer cells in the poly-L-lysine treated wells in comparison to control group (p < 0.05), (II) RGD and poly-L-lysine treatments did not cause changes in MDA or protein concentrations for the entire duration of the experiment, and (III) RGD treatment for 48 and 72 hours did not cause a reduction in the LDH activity compared to control and poly-L-lysine treated groups. Data obtained from this investigation could provide more insight regarding the design and development for safe and biocompatible orthopedic, dental and drug delivery devices.

Biocompatible Materials↗
PubMed1999

The effect on bioadhesive polymers either freely in solution or covalently attached to a support on human macrophages.

Cell surface adhesion receptors interact with a family of adhesion molecules known as integrins. It is assumed that the cells recognize and bind a specific amino acid sequence. It is likely that the host inflammatory response may be mediated via the recognition of the inflammatory cells with the specific integrin molecules. The mechanism of such behavior has not been fully elucidated. This investigation was designed to provide more insight regarding the cellular response associated with incubation of macrophages with polymers either freely in solution or adhered to surfaces. Peripheral macrophages were seeded at a density of 4 x 10(6) cells on supports coated with either amino-acid heteropolymers of RGE, RGD, or amino-acid homopolymer Poly-L-lysine. Cells were also seeded at the same density in 24 well plates and the wells were treated with RGD, RGE or Poly-L-lysine. The cells were examined morphologically and biochemically at 24, 48, and 72 hours. The results showed cells growing on supports coated with RGD had significantly (p < 0.05) higher numbers of cells adhering and remaining viable, in comparison to cells growing on Poly-L-lysine or RGE supports. Cells growing on supports coated with RGE appeared irregularly (elongated and spindle) shaped and unevenly spaced. The cells growing on Poly-L-Lysine coated supports showed cellular disruption and lysis, whereas cells growing on the RGD appeared intact, regularly spaced and began fusing into giant cells. Lactate dehydrogenase activity was used as a measure of membrane integrity, and cells grown on coated supports with Poly-L lysine showed a two-fold increase in activity over control and peptide treated groups. On the other hand, cells growing in media containing the free RGE, RGD and Poly-L-lysine showed no statistical differences in cell number, and did not show increased activity of LDH for the entire duration of the experiment. The data suggests that the RGD, RGE and Poly-L-lysine dissolved in solution are highly biocompatible to the macrophages. However, when they are attached to a support they can affect cellular adherence as well as cellular activation.

Amino Acid Sequence↗
PubMed1999

Comparison between adrenal, gonadal, and pituitary hormones on the behavior of rhesus monkey kidney cells in culture.

Recently, several studies have indicated that the use of Rhesus Monkey Kidney epithelial cells (RMKEC) in culture could provide significant knowledge regarding the alteration or dysfunction of kidney tissues that often resulted into kidney failure. The interrelationship between various steroid hormones, as well as, growth-promoting hormones such as growth hormone (GH) and RMKEC has not been fully investigated. The specific objective of this study was to investigate the effects of cortisol (C), testosterone (T), dehydroepiandrosterone (DHEA), estradiol (E), and GH on the proliferation and viability of RMKEC in culture. The cell line was adapted to grow in Morgan, Morton, and Parker's medium 199 (with 1.68 g/L sodium bicarbonate) supplemented with 1% horse serum. A total of 30 tubes were plated with RMKEC and divided into six equal groups. In-groups 1-5, each well (n = 5) were treated with a physiological dose of C, T, DHEA, E, and GH, respectively. At 24, 48, and 96 hours the cells and supernatants were collected and stored for further analysis. The biochemical markers were assessed using lactate dehydrogenase (LDH), catalase, and malinodialdehyde (MDA). Data obtained suggest that: (I) treatment of RMKEC with C and DHEA resulted in an increase in MDA levels compared to the control and other experimental groups, (II) no significant increase was observed in LDH levels in all treated tubes compared to the control group, (III) higher proliferation rate was observed in cells treated with T compared to the control group. However, treatment with C showed suppression to the proliferation rate and no significant difference was observed between DHEA, GH and the control groups. In conclusion this study suggests that steroid hormones regardless of the source of secretion (gonads or adrenals) can influence the functional capacity of RMKEC in culture.

Animals↗
PubMed1999

Histopathological evaluation of female reproductive tract exposed to sustained delivery of DHEA, and DHEA + E.

Dehydroepiandrosterone (DHEA) is a hormone produced by the adrenals that serves as a precursor for numerous steroid hormones. Conventional modes of DHEA administration were limited to injections and oral routes, which result in several drawbacks. This mandates the desire for the development of a different route of DHEA administration. Sustained delivery of DHEA by bioceramic capsules has not been fully explored. The objectives of this study were: (1) to deliver DHEA, and DHEA + estrogen in a sustained manner using tricalcium phosphate-lysine (TCPL) bioceramic capsules, and (2) to evaluate the morphological changes of reproductive and vital organs using female rats as a model. A total of twelve adult female rats (220-250 g) were randomly divided into four equal groups. Rats in Groups 1 and 2 were implanted with TCPL capsules containing 200 mg DHEA, and 600 mg DHEA (DHEA-HD), respectively. Group 3 animals were implanted with one TCPL capsule containing 200 mg of DHEA and a second TCPL capsule containing 50 mg estrogen, (DHEA + E). Group 4 represented the control group. Aseptic surgical techniques were utilized during i.p. implantation of the capsules. After implantation, body weights were recorded and blood (2 ml) samples were taken biweekly for 21 days. Pap smears were taken daily. At the end of 21 days, the animals were sacrificed using an overdose of halothane. The vital and reproductive organs were harvested, processed, embedded, sectioned and screened for cellular changes. Data obtained from these procedures revealed slight hypertrophy of the heart and kidneys. In DHEA + E implanted rats, a statistically significant increase (P < 0.05) was observed in the weights of the tubules, cervix, and uterine tissues compared to the control animals. Data obtained from this study demonstrates that the proliferative effect of sustained delivery of DHEA on the reproductive organs (ovary, cervix, uterus, and tubes) of female rats. This study provides more insights regarding the physiological alteration induced by sustained delivery of DHEA.

Animals↗
PubMed1998

PD 176252--the first high affinity non-peptide gastrin-releasing peptide (BB2) receptor antagonist.

In this paper we describe the development of a novel series of non-peptide, "balanced" neuromedin-B preferring (BB1)/gastrin-releasing peptide preferring (BB2) receptor ligands as exemplified by PD 176252. PD 176252, which exhibits nanomolar affinity for both the BB1 (Ki = 0.15 nM) and BB2 (Ki = 1.0 nM) receptors, has been demonstrated to be a competitive antagonist at these bombesin receptor subtypes.

Animals↗
PubMed1998

Genomic organization and structure of alpha-hydroxynitrile lyase in cassava (Manihot esculenta Crantz).

Two clones with homology to the alpha-hydroxynitrile lyase (HNL) cDNA clone, MeHNL10, were isolatedfrom a lambdaEMBL3 cassava (Manihot esculenta Crantz) genomic library. Analysis of the sequences showed that both genomic clones contain HNL genes (MeHNL4, MeHNL24) which are interrupted by two introns. RT-PCR analysis of MeHNL4 shows that it is expressed at high levels in seedling roots and at lower levels in cotyledons and young leaves. The deduced amino acid sequences of MeHNL4, MeHNL10, and MeHNL24 show high sequence identity and homology to the HNL from Hevea brasiliensis whose tertiary structure has been solved at 1.9-A resolution by X-ray crystallography. This high homology allowed the construction of model structures for all of the cassava proteins using the MODELLER program. Homology modeling indicates that the short variable exon 2 encodes the "cap" region which is thought to influence the substrate specificity of the protein. Two hybrid proteins were modeled using the core alpha/beta domain of MeHNL10 and the cap region of either the Hevea HNL or a structurally related Zea protein of unknown function. This analysis suggests that changes in the active site can be engineered by swapping exons.

Aldehyde-Lyases↗