The first report of otarine herpesvirus-1-associated urogenital carcinoma in a South American fur seal (Arctocephalus australis).

Otarine herpesvirus (OtHV)-1-associated urogenital carcinoma has been well documented in the California sea lion (Zalophus californianus, CSL), but this is the first report of this tumour in a captive South American fur seal (Arctocephalus australis, SAFS). The gross and microscopical morphology of the tumour in the SAFS was identical to that described previously in CSLs and the tumour in the present case had metastasized within the urogenital tract and draining lymph nodes and to the lungs and one kidney. Immunohistochemistry revealed intra- and extracytoplasmic labelling of herpesvirus antigen in the cells of the tumour tissue and transitional epithelium of the urethra. OtHV-1 nucleic acids were detected within tumour tissue and from a urogenital swab by polymerase chain reaction. The ranges of these two species of pinniped do not overlap normally in the wild, suggesting that transmission of OtHV-1 probably occurred in captivity. This confirmed susceptibility of the SAFS to the development of OtHV-1-associated urogenital carcinoma suggests that all species of Otariidae should be screened for OtHV-1 infection prior to movement within and between zoological collections.

Demographic screening for MRSA may compromise the effectiveness of ring fencing on a joint replacement unit.

Ring fencing of joint replacement (JR) units has been reported to reduce infections and is recommended by health authorities in Australia and the UK. It has not been determined whether a demographic risk assessment is adequate to prevent the admission of patients colonized with meticillin-resistant Staphylococcus aureus (MRSA) to ring-fenced units. As such, 250 admissions to the JR unit of a suburban Sydney hospital were screened, and MRSA colonization was identified in 2.8% of patients complying with the demographic risk assessment. Demographic risk assessment is not an adequate substitute for physical MRSA screening, and undermines the effectiveness of ring-fencing procedures.

The impact of pan-resistant bacterial pathogens on survival after lung transplantation in cystic fibrosis: results from a single large referral centre.

Reported actuarial one-year survival for patients with cystic fibrosis (CF) after lung transplant is 55-91%. Infection is the most common cause of early death. Colonization with Burkholderia cepacia complex is associated with reduced survival and international lung transplant referral guidelines support individual unit assessment policies for patients colonized with other pan-resistant bacteria. We examined local data on survival after transplant for CF to determine the impact of colonization with pan-resistant bacteria. A retrospective review of all CF patients from Royal Prince Alfred Hospital (RPAH), Sydney, who underwent lung transplantation at St Vincent's Hospital, Sydney, 1989-2002, was performed. Sixty-five patients were listed for lung transplantation with 54 (male: female=29:25) receiving transplants. Of the 11 patients (17%) who died on the waiting list, six were colonized with pan-resistant Pseudomonas aeruginosa. Thirty of the 54 transplanted patients had at least one pan-resistant organism before transplant. In 28 this included P. aeruginosa. Overall one-year survival was 92% with a median survival of 67 months. Overall survival for the pan-resistant group (N = 30) was not significantly different to survival in those with sensitive organisms (N = 24) (Logrank chi square = 1.6, P = 0.2). Three patients colonized with B. cepacia complex pre-transplant survive at 11, 40 and 60 months post-transplant. Infection contributed to 11 of the 18 post-transplant deaths, with pre-transplant-acquired bacterial pathogens responsible in two cases. Patients continued to acquire multiresistant bacteria post-transplantation. Lung transplant survival at St Vincent's Hospital for CF adults from RPAH compares favourably with international benchmarks. Importantly, colonization with pan-resistant bacteria pre-transplant did not appear to adversely affect survival post-transplant.

Surgery induces human mononuclear cell arginase I expression.

BACKGROUND: Arginase is a metabolic enzyme for the amino acid arginine that participates in the immune response to trauma. We hypothesize that surgical trauma induces arginase expression and activity in the human immune system. METHODS: Peripheral mononuclear cell (MNC) arginase activity and expression and plasma nitric oxide metabolites and interleukin (IL)-10 were measured in patients undergoing elective general surgery. Twenty-two healthy volunteers served as a comparison population. RESULTS: MNC arginase activity increased within 6 hours of surgery (p < 0.05) and coincided with increased arginase I protein expression. Plasma nitric oxide metabolites decreased significantly postoperatively (p < 0.05). Patients lacking an elevation in IL-10 failed to demonstrate increased MNC arginase activity. CONCLUSION: Increased MNC arginase expression may contribute to postsurgical immune dysfunction by affecting arginine use and availability and nitric oxide metabolism in the immune system. Plasma IL-10 may play a role in regulating MNC arginase activity.

Alterations in arginine metabolic enzymes in trauma.

Arginine is the sole substrate for nitric oxide (NO) synthesis by NO synthases (NOS) and promotes the proliferation and maturation of human T-cells. Arginine is also metabolized by the enzyme arginase, producing urea and ornithine, the precursor for polyamine production. We sought to determine the molecular mechanisms regulating arginase and NOS in splenic immune cells after trauma. C3H/HeN mice underwent laparotomy as simulated moderate trauma or anesthesia alone (n = 24 per group). Six, 12, 24, or 48 h later, 6 animals from each group were sacrificed, and splenectomy was performed and plasma collected. Six separate animals had neither surgery nor anesthesia and were sacrificed to provide resting values (t = 0 h). Spleen arginase I and II and iNOS mRNA abundance, arginase I protein expression, and arginase activity were determined. Plasma NO metabolites (nitrite + nitrate) were also measured. Trauma increased spleen arginase I protein expression and activity (P = 0.01) within 12 and for at least 48 h after injury and coincided with up-regulated arginase I mRNA abundance at 24 h. Neither arginase II nor iNOS mRNA abundance in the spleen was significantly increased by trauma at 24 h. Plasma nitrite + nitrate was decreased in animals 48 h post-injury compared to anesthesia controls (P < 0.05). Trauma induces up-regulation of arginase I gene expression in splenic immune cells within 24 h of injury. Arginase II is not significantly up-regulated at that time point. Arginase I, rather than iNOS appears to be the dominant route for arginine metabolism in splenic immune cells 24 h after trauma.

Arginase I expression and activity in human mononuclear cells after injury.

OBJECTIVE: To determine the effect of trauma on arginase, an arginine-metabolizing enzyme, in cells of the immune system in humans. SUMMARY BACKGROUND DATA: Arginase, classically considered an enzyme exclusive to the liver, is now known to exist in cells of the immune system. Arginase expression is induced in these cells by cytokines interleukin (IL) 4, IL-10, and transforming growth factor beta, corresponding to a T-helper 2 cytokine profile. In contrast, nitric oxide synthase expression is induced by IL-1, tumor necrosis factor, and gamma interferon, a T-helper 1 cytokine profile. Trauma is associated with a decrease in the production of nitric oxide metabolites and a state of immunosuppression characterized by an increase in the production of IL-4, IL-10, and transforming growth factor beta. This study tests the hypothesis that trauma increases arginase activity and expression in cells of the immune system. METHODS: Seventeen severely traumatized patients were prospectively followed up in the intensive care unit for 7 days. Twenty volunteers served as controls. Peripheral mononuclear cells were isolated and assayed for arginase activity and expression, and plasma was collected for evaluation of levels of arginine, citrulline, ornithine, nitrogen oxides, and IL-10. RESULTS: Markedly increased mononuclear cell arginase activity was observed early after trauma and persisted throughout the intensive care unit stay. Increased arginase activity corresponded with increased arginase I expression. Increased arginase activity coincided with decreased plasma arginine concentration. Plasma arginine and citrulline levels were decreased throughout the study period. Ornithine levels decreased early after injury but recovered by postinjury day 3. Increased arginase activity correlated with the severity of trauma, early alterations in lactate level, and increased levels of circulating IL-10. Increased arginase activity was associated with an increase in length of stay. Plasma nitric oxide metabolites were decreased during this same period. CONCLUSIONS: Markedly altered arginase expression and activity in cells of the human immune system after trauma have not been reported previously. Increased mononuclear cell arginase may partially explain the benefit of arginine supplementation for trauma patients. Arginase, rather than nitric oxide synthase, appears to be the dominant route for arginine metabolism in immune cells after trauma.

Laminin alpha4 and integrin alpha6 are upregulated in regenerating dy/dy skeletal muscle: comparative expression of laminin and integrin isoforms in muscles regenerating after crush injury.

The expression of laminin isoforms and laminin-binding integrin receptors known to occur in muscle was investigated during myogenic regeneration after crush injury. Comparisons were made between dystrophic 129ReJ dy/dy mice, which have reduced laminin alpha2 expression, and their normal littermates. The overall histological pattern of regeneration after crush injury was similar in dy/dy and control muscle, but proceeded faster in dy/dy mice. In vitro studies revealed a greater yield of mononuclear cells extracted from dy/dy muscle and a reduced proportion of desmin-positive cells upon in vitro cultivation, reflecting the presence of inflammatory cells and "preactivated" myoblasts due to ongoing regenerative processes within the endogenous dystrophic lesions. Laminin alpha1 was not detectable in skeletal muscle. Laminin alpha2 was present in basement membranes of mature myofibers and newly formed myotubes in control and dy/dy muscles, albeit weaker in dy/dy. Laminin alpha2-negative myogenic cells were detected in dy/dy and control muscle, suggesting the involvement of other laminin alpha chains in early myogenic differentiation, such as laminin alpha4 and alpha5 which were both transiently expressed in basement membranes of newly formed myotubes of dy/dy and control mice. Integrin beta1 was expressed on endothelial cells, muscle fibers, and peripheral nerves in uninjured muscle and broadened after crush injury to the interstitium where it occurred on myogenic and nonmyogenic cells. Integrin alpha3 was not expressed in uninjured or regenerating muscle, while integrin alpha6 was expressed mainly on endothelial cells and peripheral nerves in uninjured muscle. Upon crush injury integrin alpha6 increased in the interstitium mainly on nonmyogenic cells, including infiltrating leukocytes, endothelial cells, and fibroblasts. In dy/dy muscle, integrin alpha6 occurred on some newly formed myotubes. Integrin alpha7 was expressed on muscle fibers at the myotendinous junction and showed weak and irregular expression on muscle fibers. After crush injury, integrin alpha7 expression extended to the newly formed myotubes and some myoblasts. However, many myoblasts and newly formed myotubes were integrin alpha7 negative. No marked difference was observed in integrin alpha7 expression between dy/dy and control muscle, either uninjured or after crush injury. Only laminin alpha4 and integrin alpha6 expression patterns were notably different between dy/dy and control muscle. Expression of both molecules was more extensive in dy/dy muscle, especially in the interstitium of regenerating areas and on newly formed myotubes. In view of the faster myogenic regeneration observed in dy/dy mice, the data suggest that laminin alpha4 and integrin alpha6 support myogenic regeneration. However, whether these accelerated myogenic effects are a direct consequence of the reduced laminin alpha2 expression in dy/dy mice, or an accentuation of the ongoing regenerative events in focal lesions in the muscle, requires further investigation.

Beta adrenoceptor regulation of macrophage arginase activity.

BACKGROUND: Arginase, which metabolizes L-arginine within the urea cycle, is essential for production of polyamines and affects production of nitric oxide by depletion of L-arginine, the common substrate for both arginase and nitric oxide synthase. Having shown that trauma increases splenic macrophage arginase activity, we seek to define the mechanisms for this. RAW macrophage arginase activity and expression are increased by 8-bromo-cAMP in vitro. We hypothesize that since catecholamines increase cAMP, trauma-induced splenic arginase activity may be mediated by post-injury catecholamine release. METHODS: RAW 264.7 macrophage arginase activity was measured in vitro in response to 4 catecholamines with or without propranolol or lipopolysaccharide (LPS). C57BL/6 mice underwent laparotomy as a model of moderate trauma after propranolol treatment, with and without intraperitoneal Escherichia coli LPS administration as a simulated pro-inflammatory stimulus. RESULTS: Macrophage arginase activity increased in vitro in response to catecholamines or LPS (P < .05). Propranolol pretreatment blocked macrophage arginase activity induced by epinephrine (10 mumol/L) in vitro (P < .05). Trauma or LPS alone increased splenic arginase activity in vivo (P < .05). Propranolol did not alter LPS-induced splenic arginase activity but did significantly reduce trauma-induced splenic arginase activity (P < .05). CONCLUSIONS: Catecholamines alone increase macrophage arginase activity through beta-adrenoceptor activation. Increased splenic arginase activity induced by moderate trauma is decreased by beta-adrenoceptor blockade, suggesting that trauma-induced arginase activity is partly mediated by endogenous catecholamines.

Trauma increases extrahepatic arginase activity.

BACKGROUND: Although expressed primarily in the liver, arginase activity also is present in extrahepatic tissues and specifically in macrophages, where it may play diverse physiologic roles in wound healing, cellular proliferation, and the regulation of nitric oxide production. Arginase activity in immune cells is upregulated by certain cytokines such as IL-4, IL-10, and TGF-beta and by catecholamines. Since the release of these substances is increased after trauma, we hypothesized that arginase activity would also be increased in immune cells after trauma. The current work tests this hypothesis. METHODS: A model of surgical trauma was created in C3H/HeN mice by performing an exploratory laparotomy. Tissue arginase activity and arginase I protein expression were determined. As a control, arginase activity and expression were also stimulated with the use of endotoxin. In addition, we evaluated the expression of inducible nitric oxide synthase and the accumulation of nitric oxide metabolites in plasma. RESULTS: Surgical trauma was associated with a significant increase in arginase activity in splenic and renal tissues (P < .05). Splenic macrophages from trauma animals exhibited arginase activity levels approximately 10 times those of controls (P < .05). Endotoxin alone increased arginase activity in the spleen, but this increase was less than that of trauma alone (P < .05). Arginase activity remained elevated after trauma for up to 4 days and normalized by day 7. Arginase I expression was upregulated by trauma in both splenic and renal tissue and by endotoxin in the spleen only. Despite upregulation of inducible nitric oxide synthase in trauma animals, circulating nitric oxide metabolites were decreased 2 days after trauma compared with controls (P < .05). Endotoxin-induced nitric oxide metabolites were also reduced in trauma animals compared with endotoxin treatment alone (P < .05), but this normalized by day 4. CONCLUSIONS: Extrahepatic arginase expression and activity is increased after trauma and may provide the necessary precursors for cellular proliferation and repair or may play a regulatory role in the production of nitric oxide.

Survival of enterococci and staphylococci on hospital fabrics and plastic.

The transfer of gram-positive bacteria, particularly multiresistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), among patients is a growing concern. One critical aspect of bacterial transfer is the ability of the microorganism to survive on various common hospital surfaces. The purpose of this study was to determine the survival of 22 gram-positive bacteria (vancomycin-sensitive and -resistant enterococci and methicillin-sensitive and -resistant staphylococci) on five common hospital materials: smooth 100% cotton (clothing), 100% cotton terry (towels), 60% cotton-40% polyester blend (scrub suits and lab coats), 100% polyester (privacy drapes), and 100% polypropylene plastic (splash aprons). Swatches were inoculated with 10(4) to 10(5) CFU of a microorganism, assayed daily by placing the swatches in nutritive media, and examining for growth after 48 h. All isolates survived for at least 1 day, and some survived for more than 90 days on the various materials. Smaller inocula (10(2)) survived for shorter times but still generally for days. Antibiotic sensitivity had no consistent effect on survival. The long survival of these bacteria, including MRSA and VRE, on commonly used hospital fabrics, such as scrub suits, lab coats, and hospital privacy drapes, underscores the need for meticulous contact control procedures and careful disinfection to limit the spread of these bacteria.

The modulation of corneal keratocyte and epithelial cell responses to poly(2-hydroxyethyl methacrylate) hydrogel surfaces: phosphorylation decreases collagenase production in vitro.

We examined the regulation of collagenase production by rabbit keratocyte, epithelial and mixed keratocyte/epithelial cell cultures which were exposed to poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel surfaces with different chemistries and morphologies (sponge and homogeneous gels). Tissue culture modified polystyrene (TCP), used as a control surface, induced the maximum collagenase response with all cell culture types. Copolymer homogeneous gels containing 2-ethoxyethyl methacrylate (EEMA) or methyl methacrylate (MMA) induced a high response in keratocyte cultures, whilst PHEMA hydrogels induced a moderate response and the phosphorylated PHEMA (phos-PHEMA) hydrogel induced no response. Epithelial cells cultured on PHEMA, copolymer and phos-PHEMA hydrogels produced less collagenase activity than the keratocyte cells. The profile of collagenases produced by epithelial cells in response to phos-PHEMA was different to that for the other hydrogels. Co-cultured cells produced higher levels of collagenase (relative to the TCP) in response to hydrogels than did either the keratocytes or epithelial cells alone, but the response of phos-PHEMA was still the lowest. The overall enzyme response to the sponge hydrogels was lower than that to the homogeneous hydrogels, although this effect was less prominent in the keratocyte cultures. The markedly reduced and alternative collagenase responses to phosphorylated surfaces was not a consequence of cell death, and may be a phenomenon related to changes in cell surface charge and morphology.

Beneficial effects of S-adenosyl-L-methionine on blood-brain barrier breakdown and neuronal survival after transient cerebral ischemia in gerbils.

We have studied the beneficial effects of S-adenosyl-L-methionine (SAM) tosylate on blood-brain barrier (BBB) breakdown and neuronal survival after transient cerebral ischemia in gerbils. BBB breakdown experiments were performed in pentobarbital anesthetized gerbils subjected to 10 min of bilateral carotid artery occlusion and 6 h of reperfusion. For BBB breakdown measurements, SAM (120 mg/kg, i.p.) was administered to gerbils just after occlusion and thereafter every hour up to 5 h. Fluorometric measurements quantified the blood-brain permeability tracer, Evans blue (EB). SAM treatment significantly reduced the BBB breakdown as indicated by reduced levels of EB fluorescence. Neuronal count experiments were conducted in gerbils subjected to transient ischemia and 7 days of reperfusion. For neuronal count experiments SAM (15-120 mg/kg) was administered at 6 and 12 h after reperfusion, and twice each day thereafter for 7 days. SAM dose dependently protected the hippocampal CA1 neurons assessed by histopathological methods. SAM has a beneficial effect on the outcome of ischemic injury by reducing the BBB breakdown and neuronal death.

Extracellular matrix, growth factors, genetics: their influence on cell proliferation and myotube formation in primary cultures of adult mouse skeletal muscle.

Cell proliferation and myotube formation in response to growth factors on various extracellular matrices (ECM) were investigated in primary skeletal muscle cultures from adult SJL/J and BALB/c mice. There was no difference between the rates of proliferation from primary cultures of SJL/J and Balb/c mice measured at 48 h in response to a range of concentrations of PDGF-AA, -AB, -BB, TGF beta 1, or LIF (added at 24 h). SJL/J primary cultures were more responsive to bFGF (which was the most potent mitogen) than were BALB/c cultures. Comparison of dose response curves to bFGF and TGF beta 1 grown on gelatin or Matrigel showed that the nature of the ECM did not have a significant affect. More myotubes formed at 4 days in SJL/J than in parallel BALB/c cultures on gelatin or Matrigel (P < 0.05). On gelatin more myotubes with 4 or more nuclei were formed in cultures from SJL/J than BALB/c muscles (P < 0.05); however, on Matrigel these myotubes occurred with similar frequency. Myotube formation examined in BALB/c muscle cultures grown on collagen i.v., entactin-free laminin, and fibronectin showed that none of these ECM components alone supported large myotube formation (4 or more nuclei) as well as did Matrigel, although fibronectin was as effective as Matrigel with respect to the total number of myotubes formed. Parallel experiments carried out using the myogenic H-2Kb(27) cell line showed similar effects with the exception of laminin which enhanced large myotube formation and desmin expression in the H-2Kb(27) but not in the primary muscle cultures. The greater sensitivity in mitogenic response to bFGF and the more extensive myotube formation seen in SJL/J compared with BALB/c cultures in vitro reflects the superior capacity for muscle regeneration of SJL/J mice in vivo.

The role of macrophages in skeletal muscle regeneration with particular reference to chemotaxis.

The results from this investigation suggest that chemotactic factor(s) from damaged myofibers attract polymorphonuclear leukocytes (PML) and macrophages to the site of injury, while exudate macrophages but not PML induce a strong positive chemotactic response in myogenic cells. The AB and BB isoforms of platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), and leukemia inhibitory factor (LIF) (all of these are secreted by macrophages) were also shown to be chemoattractants for muscle precursor cells (MPC). The AA isoform of PDGF did not appear to have any such chemotactic effect on MPC. Macrophages were also shown, under tissue culture conditions, to stimulate the proliferation of MPC. This mitogenic effect was similarly demonstrated for the BB isoform of PDGF, bFGF, and TGF-beta but not for the AA or AB isoforms of PDGF nor for LIF. The results indicate that macrophages play a pivotal role in the orchestration of muscle fiber reconstitution.

Primary total hip reconstruction with a titanium fiber-coated prosthesis inserted without cement.

A prospective study was done of the intermediate-term clinical and radiographic results of 121 total hip arthroplasties in which a Harris-Galante porous titanium-fiber-coated prosthesis was inserted without cement in 110 patients. The average age at the time of the operation was forty-nine years (range, twenty to seventy years). The average duration of follow-up was sixty-seven months (range, fifty-five to seventy-nine months). The average preoperative Harris hip score was 55 points, and the average postoperative score was 93 points. One acetabular component was revised due to recurrent dislocation. Eleven femoral implants were unstable, and of these, four were revised. Cortical erosion was present around the distal part of the femoral stem in nine patients (8 per cent) who had stable implants, and one of these femoral implants was revised because the erosion was extensive. Survivorship analysis at five years revealed a 97 per cent chance of survival (95 per cent confidence limit, 0.937 to 1.0) of the Harris-Galante femoral-stem implant inserted without cement.

Clinical experience with primary cementless total hip arthroplasty.

One hundred-eleven patients (121 hips) treated with cementless total hip arthroplasty (Harris-Galante, Zimmer) were clinically and radiographically reviewed at an average follow-up of 67 months (55-79). 9,1% of the stems presented signs of loosening and 5 stems (4,1%) had to be revised. None of the acetabula required revision surgery for loosening. One socket was revised due to recurrent dislocation. Clinical results were evaluated according to Harris protocol: excellent 75,2%, good 12,4%, fair 5%, poor 3,3%. Ten (7,9%) intraoperative fractures of the proximal femur were observed: in 2 cases stem instability consequently occurred. Endosteal cortical erosions, not clinically evident, were observed in 8,3% of stable stems. A foreign body biological reaction to polyethylene or metallic debris is supposed as cause of erosions.

Phenotype alteration in colon carcinoma cells: effect of in vivo passage?

A panel of rat colon adenocarcinoma cell lines (the Per series) were used to investigate the phenotype and karyotype changes induced by in vivo passage in the subcutis of athymic nude mice. One poorly and one well-differentiated tumor cell line were serially passaged through the athymic nude mouse and then back to the syngeneic rat host. Each of the primary and xenograft cell lines expressed fetal crypt cell ("CaCo") antigens. The well differentiated primary and xenograft lines (Per305, Per305N1, and Per305N2a) were different in each of their growth factor responsiveness in vitro [i.e. epidermal growth factor (EGF), bombesin, vasoactive intestinal peptide], their EGF receptor expression, their secretion of transforming growth factor-alpha, and their exhibition of anchorage independent (A-I) growth capabilities. The poorly differentiated primary and xenograft cell lines were also different but were all capable of A-I growth; their responsiveness to exogenous growth factor stimulation decreased with progressive in vivo passage, as did their basal unstimulated proliferation rate. Cytogenetic alterations detected were those associated with clinical specimens from various stages of malignancy, i. e. aneuploidy, structural aberrations, and marker chromosomes. Genetic and mitogenic individuality of each line demonstrated the diversity of the growth control mechanisms in neoplasms at different stages of progression.