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Biomedical subjects

R J King

Publications and source records attributed to R J King.

At least 19 recordsLinked to original sources
PubMed2003

Primary obturator pyomyositis: a diagnostic challenge.

Pyomyositis of the obturator muscles is a rare condition, characterised by pain in the hip and features of systemic infection. It may follow minor trauma to the hip, sometimes in the presence of an apparently innocuous infective source. All previously reported cases have been diagnosed conclusively on the initial CT or MR scan. We present a case of obturator pyomyositis in a 21-year-old football player in which the first MR scan was misleading. A radiolabelled, white blood cell scan was also negative and the resultant delay in diagnosis proved dangerous. The crucial importance of careful and repeated clinical examination is emphasised.

Adult↗
PubMed2001

CTP:phosphocholine cytidylyltransferase inhibition by ceramide via PKC-alpha, p38 MAPK, cPLA2, and 5-lipoxygenase.

In a companion paper (Vivekananda J, Smith D, and King RJ. Am J Physiol Lung Cell Mol Physiol 281: L98-L107, 2001), we demonstrated that tumor necrosis factor (TNF)-alpha inhibited the activity of CTP:phosphocholine cytidylyltransferase (CT), the rate-limiting enzyme in the de novo synthesis of phosphatidylcholine (PC), and that its actions were likely exerted through a metabolite of sphingomyelin. In this paper, we explore the signaling pathway employed by TNF-alpha using C2 ceramide as a cell-penetrating sphingolipid representative of the metabolites induced by TNF-alpha. We found that in H441 cells, as reported in other cell types, cytosolic phospholipase A2 (cPLA2) is activated by TNF-alpha. We also observed that the inhibiting action of C2 ceramide on CT requires protein kinase C-alpha, p38 mitogen-activated protein kinase, and cPLA2. The actions of C2 ceramide on CT activity can be duplicated by adding 2 microM lysoPC to these cells. Furthermore, we found that the effects of C2 ceramide are dependent on 5-lipoxygenase but that cyclooxygenase II is unimportant. We hypothesize that CT activity is inhibited by the lysoPC generated as a consequence of the activation of cPLA2 by protein kinase C-alpha and p38 mitogen-activated protein kinase. The other product of the activation of cPLA2, arachidonic acid, is a substrate for the synthesis of leukotrienes, which raise intracellular Ca2+ levels and complete the activation of cPLA2.

Arachidonate 5-Lipoxygenase↗
PubMed2001

Sphingomyelin metabolites inhibit sphingomyelin synthase and CTP:phosphocholine cytidylyltransferase.

Tissue injury in inflammation involves the release of several cytokines that activate sphingomyelinases and generate ceramide. In the lung, the impaired metabolism of surfactant phosphatidylcholine (PC) accompanies this acute and chronic injury. These effects are long-lived and extend beyond the time frame over which tumor necrosis factor (TNF)-alpha and interleukin-1beta are elevated. In this paper, we demonstrate that in H441 lung cells these two processes, cytokine-induced metabolism of sphingomyelin and the inhibition of PC metabolism, are directly interrelated. First, metabolites of sphingomyelin hydrolysis themselves inhibit key enzymes necessary for restoring homeostasis between sphingomyelin and its metabolites. Ceramide stimulates sphingomyelinases as effectively as TNF-alpha, thereby amplifying the sphingomyelinase activation, and TNF-alpha, ceramide, and sphingosine all inhibit PC:ceramide phosphocholine transferase (sphingomyelin synthase), the enzyme that restores homeostasis between sphingomyelin and ceramide pools. Second, ceramide inhibits PC synthesis, probably because of its effects on CTP:phosphocholine cytidylyltransferase, the rate-limiting enzymatic step in de novo PC synthesis. The data presented here suggest that TNF-alpha may be an inhibitor of phospholipid metabolism in inflammatory tissue injury. These actions may be amplified because of the ability of metabolites of sphingomyelin to inhibit the pathways that should restore the normal ceramide-sphingomyelin homeostasis.

Ceramides↗
PubMed2001

Deficiencies in lung surfactant proteins A and D are associated with lung infection in very premature neonatal baboons.

Surfactant proteins A (SP-A) and D (SP-D) are important in the innate host defense against pathogenic microorganisms. A deficit in these proteins in premature infants, either because of immaturity or as a consequence of superimposed chronic lung disease (CLD), could increase their susceptibility to infection. The study reported here examined infection in CLD in the premature newborn baboon, and correlated it with the amounts of SP-A and SP-D in lung tissue and lavage fluid. Two groups of baboons were delivered prematurely, at 125 d gestational age (g.a.), and differed principally in whether they developed naturally acquired pulmonary infections and sepsis. Group I animals were ventilated with clinically appropriate oxygen for 6 d and 14 d without clinical incident. Group II animals were ventilated for 5 to 71 d, but differed from those in Group I in that most developed pulmonary infection and/or sepsis. In Group I animals, tissue pools of both SP-A and SP-D were equal to or exceeded those in adults, and lavage pools of SP-A increased progressively with the time of ventilation to about 35% of adult levels after 14 d. In contrast, most Group II animals had concentrations of lavage SP-A that were less than 20% of that in adult animals. A low concentration of lavage SP-A correlated with the release of interleukin-8, and with a high "infection index" based on histopathology, microbiologic cultures, and clinical indications of sepsis. Our data suggest that the amounts of SP-A and SP-D in lavage fluid are indicators of the risk of infection in the evolution of neonatal CLD. Deficits in the amount of lavage SP-A, even after 60 d of ventilation, may have inhibited the resolution of infection and thereby contributed to the developing injury among our Group II animals.

Animals↗
PubMed2000

Hepatocyte growth factor is elevated in chronic lung injury and inhibits surfactant metabolism.

Adult respiratory distress syndrome may incorporate in its pathogenesis the hyperplastic proliferation of alveolar epithelial type II cells and derangement in synthesis of pulmonary surfactant. Previous studies have demonstrated that hepatocyte growth factor (HGF) in the presence of serum is a potential mitogen for adult type II cells (R. J. Panos, J. S. Rubin, S. A. Aaronson, and R. J. Mason. J. Clin. Invest. 92: 969-977, 1993) and that it is produced by fetal mesenchymal lung cells (J. S. Rubin, A. M.-L. Chan, D. P. Botarro, W. H. Burgess, W. G. Taylor, A. C. Cech, D. W. Hirschfield, J. Wong, T. Miki, P. W. Finch, and S. A. Aaronson. Proc. Natl. Acad. Sci. USA 88: 415-419, 1991). In these studies, we expand on this possible involvement of HGF in chronic lung injury by showing the following. First, normal adult lung fibroblasts transcribe only small amounts of HGF mRNA, but the steady-state levels of this message rise substantially in lung fibroblasts obtained from animals exposed to oxidative stress. Second, inflammatory cytokines produced early in the injury stimulate the transcription of HGF in isolated fibroblasts, providing a plausible mechanism for the increased amounts of HGF seen in vivo. Third, HGF is capable of significantly inhibiting the synthesis and secretion of the phosphatidylcholines of pulmonary surfactant. Fourth, HGF inhibits the rate-limiting enzyme in de novo phosphatidylcholine synthesis, CTP:choline-phosphate cytidylyltransferase (EC 2.7.7.15). Our data indicate that fibroblast-derived HGF could be partially responsible for the changes in surfactant dysfunction seen in adult respiratory distress syndrome, including the decreases seen in surfactant phosphatidylcholines.

Animals↗
PubMed2000

PKC, p42/p44 MAPK, and p38 MAPK are required for HGF-induced proliferation of H441 cells.

In this paper, we studied the signaling pathway used by hepatocyte growth factor/scatter factor (HGF) to stimulate mitosis. We show, using H441 cells, that 1) HGF activates membrane-associated protein kinase C (PKC); the activity is transient and peaks within 30 min; 2) HGF activates p42/p44 and p38 mitogen-activated protein kinases (MAPKs); maximum activity in both is within 10 min; and 3) the activation of neither p38 nor p42/p44 MAPK is dependent on PKC, indicating that HGF uses separate and nonintersecting pathways to activate these two classes of kinase. However, phorbol 12-myristate 13-acetate also activates both MAPKs as well as PKC, but this activation is abolished in cells pretreated with the PKC inhibitor GF-109203X. HGF was found to significantly increase [(3)H]thymidine incorporation within 5 h; peak thymidine incorporation was observed at 16 h. However, when cells were pretreated with inhibitors of p42/p44 (PD-98059), p38 (SB-203580), or PKC (GF-109203X, Gö-6983, or myristoylated inhibitor peptide(19-27)), HGF-induced thymidine uptake was diminished in a dose-dependent manner. Taken together, these results demonstrate that HGF activates PKC and both MAPKs simultaneously through parallel pathways and that the activation of the MAPKs does not depend on PKC. However, p38 and p42/p44 MAPKs and PKC may all be essential for HGF-induced proliferation of H441 cells.

Adenocarcinoma↗
PubMed1999

Phacotrabeculectomy: limbus-based versus fornix-based conjunctival flaps in fellow eyes.

OBJECTIVE: To compare the effectiveness of limbus-based and fornix-based conjunctival flaps in fellow eyes of the same patients undergoing combined trabeculectomy with phacoemulsification. DESIGN: Prospective, nonrandomized comparative (fellow eye) study. PARTICIPANTS: Forty-four patients and 88 fellow eyes. INTERVENTION: Limbus-based conjunctival flap with phacotrabeculectomy was performed in one eye, and a fornix-based conjunctival flap with phacotrabeculectomy was performed in the fellow eyes of the same patients. The patients were followed up for a minimum of 1 year postoperatively for each eye. MAIN OUTCOME MEASURES: Preoperative and postoperative visual acuity, intraocular pressure, number of antiglaucoma medications, interventions, and complications were studied. RESULTS: At last follow-up visit, visual acuity improved to 20/40 or better in 88.6% of the limbus-based group and 79.6% of the fornix-based group. Preoperatively, the mean intraocular pressure in the limbus-based group was 21.4 +/- 4.8 mmHg on a mean of 2.4 +/- 1.2 glaucoma medications; in the fornix-based group, it was 21.4 +/- 4.3 mmHg on a mean of 2.3 +/- 1.1 medications. Mean intraocular pressure decreased to 15.3 +/- 3.3 mmHg (P < 0.01) on a mean of 0.2 +/- 0.5 glaucoma medications in the limbus-based group (P < 0.01). In the fornix-based group, mean intraocular pressure at last follow-up visit decreased to 15.3 +/- 4.7 mmHg (P < 0.01) on a mean of 0.2 +/- 0.5 medications (P < 0.01). Postoperative interventions and complications were not statistically different between the two groups. CONCLUSION: With phacotrabeculectomy, limbus-based and fornix-based conjunctival flaps are equally effective in improving visual acuity and lowering intraocular pressure. This variation in conjunctival flap orientation was equally effective in fellow eyes of the same patients, with no difference in postoperative complications or outcomes.

Aged↗
PubMed1999

A mitochondrial marker for red algal intraspecific relationships.

Intraspecific studies of red algae have relied on nuclear or plastid markers rather than mitochondrial data to address questions of systematics, biogeography or population genetics. In this study, primers were developed that spanned the noncoding intergenic region between the mitochondrial cytochrome oxidase subunit 2 and cytochrome oxidase subunit 3 genes. These primers were demonstrated to be successful on a variety of red algae in different orders: Gracilariales, Bonnemaisoniales and Ceramiales (families: Delesseriaceae, Ceramiaceae and Rhodomelaceae). Amplification products were between 450 and 320 bp in length, with variation in length shown among geographically distant isolates within a species. The region was variable within a single species, as shown for Bostrychia moritziana and B. radicans, and within populations of Caloglossa leprieurii. In the latter species, four mitochondrial haplotypes were observed in isolates from a single locality in Woolooware Bay, New South Wales, Australia. Analysis of hybrids between different mitochondrial haplotypes of B. moritziana revealed that the mitochondria are maternally inherited in this species. This is the first report of a mitochondrial marker that is variable within red algal populations and may lead to a better understanding of the population ecology of these important marine organisms.

Base Sequence↗
PubMed1999

Surfactant proteins A and D in premature baboons with chronic lung injury (Bronchopulmonary dysplasia). Evidence for an inhibition of secretion.

Surfactant proteins A and D (SP-A and SP-D) are believed to participate in the pulmonary host defense and the response to lung injury. In order to understand the effects of prematurity and lung injury on these proteins, we measured the amounts of SP-A and SP-D and their mRNAs in three groups of animals: (1) nonventilated premature baboon fetuses; (2) neonatal baboons delivered prematurely at 140 d gestation age (ga) and ventilated with PRN O(2); (3) animals of the same age ventilated with 100% O(2) to induce chronic lung injury. In nonventilated fetuses, tissue and lavage SP-A were barely detectable in baboons of 125 and 140 d ga, but they equaled or exceeded adult SP-A concentrations (g/g lung dry wt) at 175 d (term gestation, 185 d). In contrast, SP-D was readily detectable in tissue and lavage at 125 and 140 d ga. When the baboons of 140 d ga were ventilated for 10 d with 100% oxygen to produce chronic lung injury, the tissue concentration of SP-A was five times greater than that of normal adults; SP-D 16-times greater. Despite the sizable tissue pools of SP-A and SP-D, however, lavage SP-A was only 7% of that of normal adults and lavage SP-D just equaled the amount in normal adults. Nevertheless, because SP-D is normally in much lower concentration than is SP-A, their total comprised less than 12% of the SP-A and SP-D found in the lavage of a healthy adult. The results indicate that in chronic lung injury, SP-A is significantly reduced in the alveolar space. SP-D concentration in lavage is about equal to that in normal adults, possibly because of the 16-fold excess in tissue, but the total collectin pool in lavage is still significantly reduced. Because these collectins may bind and opsonize bacteria and viruses, decrements in their amounts may present additional risk to those premature infants who require prolonged periods of ventilatory support.

Analysis of Variance↗
PubMed1998

Somatization in young versus older female panic disorder patients.

BACKGROUND AND RATIONALE: Studies in younger patients with panic disorder suggest greater somatization compared to similarly aged normal controls. Thus, we compared the degree of somatization in young versus older female patients with panic disorder to ascertain whether similarly high levels of somatization exist in older panic disorder patients. METHOD: Community-dwelling subjects were recruited for clinical trials for panic disorder and met Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria for panic disorder as a primary diagnosis. Our sample (N = 64) contained 42 younger females (< 55 years of age; age range 21-54, mean age 34.6) who were compared to 22 older females (> or = 55 years of age; age range 55-73, mean age 60.8). Subjects were evaluated at baseline using the Self-Report Inventory for Somatic Symptoms (SISS). Statistical analysis of total somatization disorder scores (TSDS) was accomplished by t-tests for independent groups. RESULTS: Older patients showed statistically significantly higher total somatization disorder scores (TSDS) (X = 11.54, SD = 7.45) than did younger patients (X = 8.07, SD = 4.77; t(62) = 2.27, p = < 0.05). CONCLUSION: Our results are suggestive of a higher degree of somatization in older compared to younger female panic disorder patients.

Adult↗
PubMed1997

Relative expression and stability of a chromosomally integrated and plasmid-borne marker gene fusion in environmentally competent bacteria.

A xylE-iceC transcriptional fusion was created by ligatinga DNA fragment harboring the cloned xylE structural gene from the TOL plasmid of Pseudomonas putida mt-2 into the cloned iceC gene of Pseudomonas syringae Cit7. This fusion construct was integrated into the chromosome of Pseudomonas syringae Cit7 by homologous recombination. Both cis-merodiploid strain Cit7m17 and marker exchange strain Cit7h69 produced the XylE gene product, catechol2,3-dioxygenase. Strain Cit7m17, in which XylE was influenced by transcription initiated by the amp promoter on pBR322, exhibited XylE activity in stationary phase at levels about 45 times higher than strain Cit7h69, permitting detection of 10(7) Cit7m17 cells in the spectrophotometric assay and 10(3) cells in HPLC measurements. The stability of xylE in both Cit7m17 and Cit7h69 was compared with maintenance of xylE in several plasmid-borne constructs in P.aeruginosa, Erwinia herbicola, and Escherichia coli. Only the xylE-iceC fusion in the chromosome of Cit7h69 and Cit7m17was stable in plate assays over the course of these studies. Even though strain Cit7h69 stably expressed xylE, the low level of expression precludes its use in direct spectrophotometric or HPLC assays as a means for detecting cells in environmental samples. However, expression of xylEin Cit7h69 is sufficient for identification of colonies harboring this marker gene which is useful in laboratory plate assays, and as a marker gene system for the detection of environmentally-competent strains chromosomally taggedwith xylE for use in autecological studies.

Bacterial Outer Membrane Proteins↗
PubMed1997

Heat-shock protein 27 (HSP27) and its role in female reproductive organs.

Heat shock, other environmental and pathophysiological stress stimulate synthesis of heat shock proteins (HSP) family. These proteins enable the cell to survive and recover from stressful conditions but as yet incompletely understood mechanisms. Beside its role in thermotolerance, it plays a role in cell proliferation and drug resistance which makes this protein of special clinical interest. Published data suggest that HSP27 is related to estrogen in breast and to estrogen and progesterone in the endometrium. It has been shown that some but not all estrogen positive breast cancers express HSP27, and overexpression has been associated with the degree of tumor differentiation, and response to hormonal therapy (Tamoxifen). In endometrial carcinomas, the presence of HSP27 is correlated with the degree of tumor differentiation as well as with the presence of oestrogen and progesterone receptors. Studies suggest that detection of HSP27 in endometrial carcinoma, should not be considered as a method for identifying hormone-responsive tumors or indicator or presence of estradiol receptors. In the cervix HSP27 is a marker of cell differentiation, and is highly expressed during the process of squamous metaplasia. Expression in the ovary is still controversial and requires further confirmation of recent observations.

Breast↗
PubMed1996

Outcome of unrelated donor bone marrow transplantation in 40 children with Hurler syndrome.

Long-term survival and improved neuropsychological function have occurred in selected children with Hurler syndrome (MPS I H) after successful engraftment with genotypically matched sibling bone marrow transplantation (BMT). However, because few children have HLA-identical siblings, the feasibility of unrelated donor (URD) BMT as a vehicle for adoptive enzyme therapy was evaluated in this retrospective study. Forty consecutive children (median, 1.7 years; range, 0.9 to 3.2 years) with MPS I H received high-dose chemotherapy with or without radiation followed by BMT between January 27, 1989 and May 13, 1994. Twenty-five of the 40 patients initially engrafted. An estimated 49% of patients are alive at 2 years, 63% alloengrafted and 37% autoengrafted. The probability of grade II to IV acute graft-versus-host disease (GVHD) was 30%, and the probability of extensive chronic GVHD was 18%. Eleven patients received a second URD BMT because of graft rejection or failure. Of the 20 survivors, 13 children have complete donor engraftment, two children have mixed chimeric grafts, and five children have autologous marrow recovery. The BM cell dose was correlated with both donor engraftment and survival. Thirteen of 27 evaluable patients were engrafted at 1 year following URD BMT. Neither T-lymphocyte depletion (TLD) of the bone marrow nor irradiation appeared to influence the likelihood of engraftment. Ten of 16 patients alive at 1 year who received a BM cell dose greater than or equal to 3.5 x 10(8) cells/kg engrafted, and 62% are estimated to be alive at 3 years. In contrast, only 3 of 11 patients receiving less than 3.5 x 10(8) cells/kg engrafted, and 24% are estimated to be alive at 3 years (P = .05). The mental developmental index (MDI) was assessed before BMT. Both baseline and post-BMT neuropsychological data were available for 11 engrafted survivors. Eight children with a baseline MDI greater than 70 have undergone URD BMT (median age, 1.5 years; range, 1.0 to 2.4 years). Of these, two children have had BMT too recently for developmental follow-up. Of the remaining six, none has shown any decline in age equivalent scores. Four children are acquiring skills at a pace equal to or slightly below their same age peers; two children have shown a plateau in learning or extreme slowing in their learning process. For children with a baseline MDI less than 70 (median age, 2.5 years; range, 0.9 to 2.9 years), post-BMT follow-up indicated that two children have shown deterioration in their developmental skills. The remaining three children are maintaining their skills and are adding to them at a highly variable rate. We conclude that MPS I H patients with a baseline MDI greater than 70 who are engrafted survivors following URD BMT can achieve a favorable long-term outcome and improved cognitive function. Future protocols must address the high risk of graft rejection or failure and the impact of GVHD in this patient population.

Bone Marrow Transplantation↗
PubMed1996

Detection and distribution of heat shock proteins 27 and 90 in human benign and malignant prostatic tissue.

OBJECTIVE: To determine whether it is possible to predict the behaviour of prostate tumours by identifying cellular characteristics, specifically specific heat shock proteins (HSPs). MATERIALS AND METHODS: An immunohistochemical study staining for HSP 27 and 90 was undertaken on 15 benign and 13 malignant samples of freshly frozen prostatic tissue obtained from patients with a similar age range in each group (benign, mean age 71.6 years, range 61-86; malignant, mean age 72.7 years, range 58-87). Gleason scores for the tumours ranged from 2 to 8. RESULTS: Consistent patterns of cytoplasmic staining were seen in all sections of tissue from benign prostatic hyperplasia (BPH). The stroma stained strongly positive for HSP 27, but negatively for HSP 90 and glandular epithelium showed positive apical staining for both HSPs. Stromal patterns in prostatic carcinoma tissue were similar to that of BPH tissue for both HSP 27 and 90. Areas of prostatic intra-epithelial neoplasia stained as strongly as did adjacent areas of BPH. For HSP 27, there was varied staining of individual epithelial cells, suggesting cellular heterogeneity, with an apparent reduction in staining with increasing Gleason score and invasiveness. For HSP 90, this pattern was less marked, with a predominance for positive staining throughout all grades of carcinoma. CONCLUSIONS: The distribution of HSPs, primarily HSP 27, may aid in identifying different cell populations within prostatic carcinomas and thus help forecast biological behaviour.

Aged↗
PubMed1996

Lymphocyte subset infiltration patterns and HLA antigen status in colorectal carcinomas and adenomas.

Fifty eight large bowel adenocarcinomas and 20 adenomas were studied immunohistochemically, using fresh frozen tissue sections, with regard to lymphocyte subpopulations (CD3, CD4, CD8, CD19, and CD20) in the inflammatory infiltrate and to expression of human leucocyte antigens (HLA-ABC, HLA-A2, and HLA-DR). The findings were related to differentiation and Duke's stage of carcinoma. The inflammatory infiltrate was found to have a phenotype that remained constant irrespective of the intensity of the inflammation. CD4 and CD3 positive cells predominated with fewer CD8 positive cells and a scanty diffuse CD19/20 positive cell population. CD19/20 follicular aggregates were common at the advancing margin of the carcinomas. There was no significant association with Duke's stage, differentiation or HLA status. HLA changes (ABC loss, A2 loss, and DR gain) were associated with differentiation, being more common and more extensive in poorly differentiated carcinomas. HLA-A2 loss was also associated with stage of progression of carcinoma. Inflammation associated with adenomas was found to have a similar phenotype to that associated with carcinomas. HLA changes in adenomas were uncommon, being seen in only one of our 20 cases.

Adenocarcinoma↗
PubMed1995

Molecular modelling of the human estrogen receptor and ligand interactions based on site-directed mutagenesis and amino acid sequence homology.

A molecular model of the human estrogen receptor is reported based on a new alignment with the alpha 1-antitrypsin sequence, a homologous protein of known crystal structure. The putative ligand binding site is situated roughly equidistant between the DNA binding and dimerization regions. This binding site contains a number of amino acid residues shown by site-directed mutagenesis to be associated with the binding of agonists and antagonists. This putative ligand binding pocket is well-defined within a loop of peptide, containing complementary amino acids for binding interactions with agonists and antagonists. A leucine-rich region, common to most steroid-binding proteins, is in an optimum position for dimerization leading to DNA interaction. It is likely that ligand binding influences dimerization and DNA interaction by a conformational change in the receptor via the transcriptional activation residues. This model suggests that ligand binding may affect the hydrogen bonding pattern such that transpeptide signalling is initiated. The model accommodates steroidal estrogens and antiestrogens as well as the non-steroidal partial antagonist, hydroxytamoxifen.

Computer Simulation↗