Lead toxicity and endoscopic removal of ingested firearm cartridges.

CONTEXT: Lead toxicity from the ingestion of a lead foreign body has been described in several case reports. Management of ingested live ammunition presents its own challenges due to the risk of accidental discharge. A safe and effective method of retrieving a live cartridge must be considered. CASE DETAILS: We present two cases of lead toxicity due to intact firearm cartridge ingestion with the removal of the cartridges via endoscopy. The first case is of severe pediatric lead toxicity due to the ingestion of 30-mm rifle cartridges. The second case is an adult ingestion of .22 caliber cartridges resulting in mild lead toxicity. DISCUSSION: These cases illustrate a diagnostic dilemma in both the diagnosis of lead toxicity and the removal of live ammunition from the stomach.

Network meta-analysis of indomethacin versus ibuprofen versus placebo for PDA in preterm infants.

OBJECTIVES: To evaluate the effects of indomethacin or ibuprofen compared with placebo on closure, morbidity and mortality in preterm infants <37 weeks' gestation with echocardiographically and/or clinically important patent ductus arteriosus (PDA) at >24 h of life. DATA SOURCES: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, Cochrane Library, clinicaltrials.gov, controlled-trials.com, American Pediatric and European Paediatric Research Societies and Effective Care of the Newborn Infant. REVIEW METHODS: Systematic review with network meta-analysis of randomised studies comparing intravenous indomethacin, ibuprofen or placebo for PDA in preterm infants at >24 h of life. RESULTS: Ten trials compared intravenous indomethacin versus intravenous ibuprofen, nine intravenous indomethacin versus placebo and one intravenous ibuprofen versus placebo. Both intravenous indomethacin (pooled RR 2.39 (95% CI 2.05 to 2.78)) and intravenous ibuprofen (RR 2.40 (95% CI 2.03 to 2.84)) closed a PDA more effectively than placebo. Intravenous ibuprofen was associated with approximately 30% greater risk of chronic lung disease than intravenous indomethacin (RR 1.28 (95% CI 1.03 to 1.60)) or placebo (RR 1.29 (95% CI 0.99 to 1.70)). Differences in risk or benefit were not significant between any combination of intravenous indomethacin, intravenous ibuprofen or placebo groups for intraventricular haemorrhage, necrotising enterocolitis and death. Reporting on neurological outcomes was insufficient for pooling. CONCLUSIONS: Intravenous indomethacin or ibuprofen administered to preterm infants for PDA at >24 h of life promoted ductal closure, but other short-term benefits were not seen. Treatment with intravenous ibuprofen may increase the risk of chronic lung disease. Good-quality evidence of treatment effect on morbidity, mortality and improved neurodevelopment is urgently needed.

Pitfalls and artefacts in performance and interpretation of contrast-enhanced MR angiography of the lower limbs.

Peripheral contrast-enhanced MR angiography is widely used for anatomical imaging of the arterial system of the lower limb. There are several pitfalls in the planning, acquisition, and interpretation of these studies that can result in the loss of important diagnostic information, as well as artefacts that can be misinterpreted as disease entities. This review illustrates the range of these potential sources of error and how to avoid them.

AIDIT and IMPACT: building research collaborations in targeted prostate cancer screening.

AIDIT (Advancing International Co-operation and Developing Infrastructure for Targeted Screening of Prostate Cancer in Men with Genetic Predisposition) is a project funded by the Sixth Framework Programme of the European Community which is endeavouring to facilitate co-operation between European countries in the field of cancer research. The project also aims to raise awareness of familial prostate cancer among health professionals and the public within the associated candidate countries (ACCs) and new member states of the European Union (EU). AIDIT will focus on linking clinical and research teams in the ACCs and new member states with the IMPACT Consortium (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), an international team investigating screening and diagnosis for men with a genetic risk of prostate cancer predisposition genes BRCA1 or BRCA2). Cancer research has been targeted as a high priority for the European Community; however, research is most successful when centralised and well coordinated, avoiding the duplication and fragmentation associated with smaller, isolated studies. AIDIT will consolidate the current IMPACT consortium and allow research partners from across the world to benefit from shared knowledge and experience. To date, the AIDIT team has established a website to facilitate communication between project collaborators (www.impact-study.co.uk), has been represented at several international meetings and has facilitated a conference for the IMPACT study to bring together international research teams, clinicians and policy makers.

Analysis of secondary electron emission spectra of equal-LET protons and alpha particles for purposes of radiation quality and spaceflight hazard assessment.

Amongst the great variety of heavy particles present in the galactic and solar cosmic ray spectra, hydrogen and helium nuclei are significantly more abundant than all other heavier ions and, as such, represent a major radiation hazard to humans in space. Experimental data have suggested that differences in relative biological effectiveness (RBE) exist between the two species at the same value of linear energy transfer (LET). This has consequences for heavily ionising radiation protection procedures, which currently still assume a simple dependence of radiation quality on LET. By analysing the secondary electron (delta-ray) emission spectra of protons and alpha particles, in terms of the spatial characteristics of energy deposition in cellular targets and the likelihood of complex lesion formation, a numerical quantity representing biological effectiveness is generated. When expressed relative to a reference radiation, this quantity is found to differ for protons and a particles of the same LET, demonstrating not only the ion-specific nature of RBE but also the inadequacy of specifying radiation quality as a function of LET only. Such a method for numerically assessing radiation quality may have implications for procedures for heavy ion protection in space at low doses and for understanding the initial mechanisms of radiation action.

Regional (spinal, epidural, caudal) versus general anaesthesia in preterm infants undergoing inguinal herniorrhaphy in early infancy.

BACKGROUND: With improvements in neonatal intensive care, more premature infants are surviving the neonatal period. With this increase, more are presenting for surgery in early infancy. Of predominance in this period is the repair of inguinal herniae, appearing in 38% of infants whose birth weight is between 751g and 1000g. Most postoperative studies show that approximately 20% to 30% of otherwise healthy former preterm infants having inguinal herniorrhaphy under general anaesthesia have one or more apnoeas in the postoperative period. Regional anaesthesia might reduce postoperative apnoea in this population. OBJECTIVES: To determine if regional anaesthesia, in preterm infants undergoing inguinal herniorrhaphy, reduces post-operative apnoea, bradycardia, and the use of assisted ventilation, in comparison to those infants undergoing inguinal herniorrhaphy with general anaesthesia. SEARCH STRATEGY: Randomised controlled trials were identified by searching MEDLINE (1966-Nov 2002), EMBASE (1982-Nov 2002), Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2002), reference lists of published trials and abstracts published in Pediatric Research. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials of spinal versus general anaesthesia in preterm infants undergoing inguinal herniorrhaphy in early infancy. DATA COLLECTION AND ANALYSIS: Data were extracted and the analyses performed independently by two reviewers. Authors of each eligible study were contacted for missing data. Studies were analysed for methodologic quality using the criteria of the Cochrane Neonatal Review Group. All data were analysed using RevMan 4.1. When possible meta-analysis was performed to calculate typical relative risk, typical risk difference, along with their 95% confidence intervals (CI). MAIN RESULTS: Four small trials comparing spinal with general anaesthesia in the repair of inguinal hernia were identified. One trial was excluded due to inadequate information. There was no statistically significant difference in the proportions of infants having postoperative apnoea/bradycardia, typical RR 0.69 (0.40, 1.21) or postoperative oxygen desaturations, RR 0.91 (0.61, 1.37). If infants having preoperative sedatives were excluded, then the meta-analysis supported a reduction in postoperative apnoea in the spinal anaesthetic group, typical RR 0.39 (0.19, 0.81). There was a reduction of borderline statistical significance in the use of postoperative assisted ventilation with spinal anaesthesia. There was an increase of borderline statistical significance in anaesthetic placement failure when spinal anaesthesia was attempted. REVIEWER'S CONCLUSIONS: There is no reliable evidence from the trials reviewed concerning the effect of spinal as compared to general anaesthesia on the incidence of post-operative apnoea, bradycardia, or oxygen desaturation in ex-preterm infants undergoing herniorrhaphy. The estimates of effect in this review are based on a total population of only 108 patients or fewer.A large well designed randomised controlled trial is needed to determine if spinal anaesthesia reduces post-operative apnoea in ex-preterm infants not pretreated with sedatives. Adequate blinding, follow up and intention to treat analysis are required.

Overexpression of manganese superoxide dismutase suppresses increases in collagen accumulation induced by culture of mesangial cells in high-media glucose.

Superoxide has been implicated in the cellular signalling pathways, which regulate growth of mesangial cells (MC) and vascular smooth muscle cells. Manganese (Mn)(2+)-dependent superoxide dismutase (SOD-2) is primarily responsible for metabolism of superoxide produced in mitochondria by respiratory chain activity during aerobic metabolism of glucose and other substrates. In the current studies, we examined the role of superoxide in the stimulation of collagen accumulation induced in MC by culture in media containing a high concentration of glucose. Aconitase, an iron sulfur enzyme whose activity is inhibited by superoxide, was used as an index of cellular superoxide production and action. SV-40-transformed mouse MC were cultured in media containing 100 (low) or 500 (high) mg/dL D-glucose and infected with a recombinant adenoviral (Ad) vector encoding either human mitochondrial Mn(2+) SOD-2 or green fluorescent protein (GFP). In cells infected with SOD-2 (SOD-2-Ad) and cultured in low glucose, SOD-2 activity was 5-fold higher than in cells infected with GFP (GFP-Ad), whereas Cu(2+)/Zn(2+) cytoplasmic SOD (SOD-1) did not differ; culture in high-glucose media did not alter SOD-2 or SOD-1 activity in either GFD-Ad or SOD-2-Ad. In GFP-Ad, high glucose suppressed aconitase activity and increased collagen accumulation compared with corresponding values in low glucose. In SOD-2-Ad, high glucose failed to suppress aconitase activity or increase collagen accumulation. Addition of exogenous (presumably extracellular) SOD to GFP-Ad had no effect on the stimulation of collagen accumulation by high glucose. Analogous to the effects of SOD-2-Ad, diphenylene iodonium (DPI), a nonspecific inhibitor of the production of superoxide by mitochondrial respiration and other nicotinamide adenine dinucleotide (phosphate) (NAD)(P)H oxidase activities, reduced collagen accumulation in GFP-Ad cultured in low glucose and blocked stimulation of collagen accumulation induced by culture in high glucose. These results support a role for increased cellular superoxide production derived from NAD(P)H oxidase activity in the stimulation of collagen accumulation induced in MC by high glucose and demonstrate that an increase in mitochondrial SOD-2 activity suppresses this response.

Overexpression of Cu2+/Zn2+ superoxide dismutase protects against early diabetic glomerular injury in transgenic mice.

Ex vivo and in vitro observations implicate superoxide as a mediator of cell injury in diabetes, but in vivo evidence is lacking. In the current studies, parameters of glomerular injury were examined in hemizygous nondiabetic transgenic mice (SOD) and streptozotocin-diabetic (D) transgenic mice (D-SOD), which overexpress human cytoplasmic Cu2+/Zn2+ superoxide dismutase (SOD-1), and in corresponding wild-type littermates (WT, D-WT) after 4 months of diabetes. In both SOD and D-SOD mice, renal cortical SOD-1 activity was twofold higher than values in the WT mice; blood glucose and glycosylated hemoglobin (GHb) levels did not differ in the two diabetic groups. Urinary albumin excretion, fractional albumin clearance, urinary transforming growth factor-beta (TGF-beta) excretion, glomerular volume, glomerular content of immunoreactive TGF-beta, and collagen alpha1 (IV) and renal cortical malondialdehyde (MDA) levels were significantly higher in D-WT mice compared with corresponding values in D-SOD mice. Glomerular volume, glomerular content of TGF-beta and collagen IV, renal cortical MDA, and urinary excretion of TGF-beta in D-SOD mice did not differ significantly from corresponding values in either the nondiabetic SOD or WT mice. In separate groups of mice studied after 8 months of diabetes, mesangial matrix area, calculated as a fraction of total glomerular tuft area, and plasma creatinine were significantly higher in D-WT but not in D-SOD mice, compared with corresponding values in the nondiabetic mice. In vitro infection of mesangial cells (MC) with a recombinant adenovirus encoding human SOD-1 increased SOD-1 activity threefold over control cells and prevented the reduction of aconitase activity, an index of cellular superoxide, and the increase in collagen synthesis that otherwise occurred in control MC in response to culture with 300 or 500 mg/dl glucose. Thus, increases in cellular SOD-1 activity attenuate diabetic renal injury in vivo and also prevent stimulation of MC matrix protein synthesis induced in vitro by high glucose.

Regulation of the laminin C1 promoter in cultured mesangial cells.

Expression of the genes encoding several matrix proteins, including the laminin gamma1 and beta1 subunits, is increased in glomeruli or renal cortex from diabetic animals or in mesangial cells cultured in high concentrations of glucose. Transforming growth factor (TGF)-beta1 and IGF-1 have been implicated as mediators of this response. In the present study, we assessed the influence of high glucose concentrations and the roles of TGF-beta1 and IGF-1 in the regulation of laminin C1 gene expression in cultured mesangial cells. Culture of normal rat mesangial cells (RMC) or SV40-transformed mouse mesangial (MES-13) cells in 500 mg/dl D-glucose for 2 days to 3 weeks significantly increased laminin C1 mRNA abundance compared with cells cultured in 100 mg/dl D-glucose. IGF-1 also increased laminin C1 mRNA abundance in RMC or MES-13 cells, whereas TGF-beta1 was without effect. The influence of raising the medium glucose concentration on laminin C1 promoter activity was further studied in MES-13 cells that had been stably transfected with a reporter gene containing the promoter linked to luciferase. Culture in 500 mg/dl D-glucose for 4 h to at least 1 week increased laminin C1 promoter activity compared with cells maintained in 100 mg/dl glucose. In contrast, culture of cells in medium that contained 400 mg/dl mannitol or 400 mg/dl L-glucose in addition to 100 mg/dl D-glucose did not increase laminin C1 promoter activity. The ability of high glucose to increase laminin C1 promoter activity was absolutely dependent on the presence of serum. Consistent with results obtained with mRNA, TGF-beta1 had no influence on promoter activity in stable integrants. Whereas IGF-1 transiently increased promoter activity in stable integrants, the increase was not sustained (6 h). Moreover, neutralizing antibody to TGF-beta or to IGF-1 receptor did not suppress increases in laminin C1 promoter activity induced by culture of stable integrants in high glucose. Several inhibitors of protein kinase C, including bisindolylmaleimide (GFX), myristoylated PKC inhibitor peptide, and LY333531, were also without effect on increases in laminin C1 promoter activity induced by culture in high glucose. Exposure to the NO donor (+/-)-s-nitroso-n-acetylpenicillamine (SNAP) blocked increases in laminin C1 promoter activity induced by serum and by culture in high glucose without influencing promoter activity in cells cultured in the absence of serum and in 100 mg/dl glucose. The ability of high glucose concentrations and IGF-1 to increase laminin C1 promoter activity in cultured mesangial cells, and the suppression of glucose actions by the NO donor SNAP, provide potential mechanisms whereby the synthesis of the laminin gamma1 chain may be regulated in the glomerulus in diabetes. Of note, the mechanism by which high glucose increases laminin C1 promoter activity appears to differ from mechanisms previously described for some other glucose actions on matrix protein synthesis. In this regard, TGF-beta and protein kinase C were not implicated as mediators of the effect of high glucose on laminin C1 promoter activity.

Effects of supplementation with vitamin C or E on albuminuria, glomerular TGF-beta, and glomerular size in diabetes.

Oxidant stress and a reduction in antioxidant status, including reduced plasma and tissue ascorbic acid content, occur in diabetic patients and experimental models of diabetes. In this study, the effects of treatment of streptozotocin diabetic rats for 2 mo with vitamin C (10 g/kg body wt/d) or dietary vitamin E (200 mg/kg body wt/d) in the drinking water on urinary albumin excretion, glomerular transforming growth factor (TGF)-beta content, and glomerular size were examined. Treatment of diabetic rats with vitamin C or E had no effect on blood glucose levels compared with that in untreated diabetics (453 +/- 28 g/dl +/- SEM). Body weight, BP, and creatinine clearance rates were not significantly different among the study groups. Kidney weight was significantly higher in all of the diabetic groups compared with age-matched control rats. Treatment with vitamin C, but not vitamin E, significantly reduced kidney weight compared with that in untreated diabetic rats. Immunohistochemical staining for TGF-beta was 2.5-fold higher in glomeruli of cortical sections from untreated diabetic rats versus control rats. Treatment with vitamin C or E prevented the increase in glomerular TGF-beta immunoreactivity. Glomerular volume was also significantly increased (twofold) in kidneys of untreated diabetic rats compared with control rats, as assessed by light microscopy. Treatment with vitamin C prevented and treatment with vitamin E reduced the increase in glomerular volume. Treatment with vitamin C also prevented the sevenfold increase in albumin clearance otherwise seen in untreated diabetic rats. By contrast, treatment with vitamin E had no effect on albumin clearance despite reductions in glomerular size and TGF-beta. Renal cortical vitamin E and plasma, but not renal cortical vitamin C, were reduced in diabetic rats versus control rats. Supplementation of diabetic rats with vitamin C markedly increased plasma and renal cortical vitamin C content to values greater than those in control rats. Supplementation with vitamin E increased renal cortical vitamin E content by 50% compared with values in control rats and also increased plasma and renal cortical vitamin C. These results support the potential utility of antioxidant treatment for the prevention of renal injury in diabetes.

Antioxidant inhibition of protein kinase C-signaled increases in transforming growth factor-beta in mesangial cells.

Protein kinase C (PKC)-signaled increases in transforming growth factor beta (TGF beta) have been implicated in the stimulation of matrix protein synthesis induced by high concentrations of glucose, thromboxane, angiotension II (AII), and other stimuli in cultured glomerular mesangial cells. In the present study, the effects of several antioxidants on mesangial cell responses to high glucose, thromboxane, and AII were examined. alpha-Tocopherol blocked increases in PKC, TGF beta bioactivity, collagen, and/or fibronectin synthesis induced in mesangial cells by high glucose, the thromboxane analog U46619, and AII. By contrast, alpha-tocopherol did not alter increases in matrix protein synthesis in mesangial cells in response to exogenous TGF beta, a cytokine that does not activate PKC in mesangial cells and whose actions to stimulate matrix protein synthesis in these cells are not blocked by PKC inhibition or downregulation. Taurine and N-acetylcystein similarly inhibited activation of PKC and increases in TGF beta in response to high glucose, U46619, and AII. alpha-Tocopherol but not taurine or N-acetylcysteine partially blocked increases in PKC activity in mesangial cells in response to the diacylglycerol (DAG) analog, phorbol dibutyrate (PDBu). Thus, alpha-tocopherol may have direct effects on interaction of the PKC system of mesangial cells with DAG that are not shared by N-acetylcysteine or taurine. Increases in TGF beta have been implicated in the pathogenesis of glomerulosclerosis in diabetes and other nephropathies. The capacity of antioxidants to block increases in TGF beta in mesangial cells in response to high glucose, thromboxane, and All suggests their potential therapeutic utility to attenuate glomerulosclerosis.

Nitric oxide inhibition of transforming growth factor-beta and collagen synthesis in mesangial cells.

Culture of mesangial cells (MCs) in 5.6 vs. 30.0 mmol/l glucose for 3 weeks induced a sustained increase in protein kinase C (PKC) activity, transforming growth factor (TGF)-beta1 mRNA, bioactive TGF-beta, and collagen synthesis. Nitric oxide (NO), generated exogenously by the NO donor S-nitroso-N-acetyl, D,L-penicillamine (SNAP) or endogenously after the exposure of MC to interleukin-1beta (IL-1beta), suppressed bioactive TGF-beta in MCs cultured in 5.6 or 30.0 mmol/l glucose and suppressed or abolished increases in TGF-beta1 mRNA and collagen synthesis induced by high concentrations of glucose or phorbol 12,13-dibutyrate without altering values obtained with normal glucose concentrations. SNAP had a transient suppressive effect on PKC activity, which may explain at least in part some of the actions of SNAP. The selective inhibitor of PKC, bisindolylmaleimide (GFX), mimicked NO action. The ability of SNAP and IL-1beta to suppress TGF-beta and collagen synthesis was not mediated by cGMP, since the cGMP analog, 8-Br-PET-cGMP, did not mimic NO action and an antagonist of cGMP-dependent protein kinase, Rp-8-pCPT-cGMPs, did not prevent the inhibitory actions of SNAP. N-omega-L-arginine methyl ester (NMMA) increased TGF-beta in glomerular capillary endothelial cells (GCECs) and stimulated collagen synthesis by MC in a co-culture with GCECs. Captopril inhibited TGF-beta and collagen synthesis and increased cGMP in co-cultures of GCECs and MCs. These effects of captopril were abolished by NMMA, implying mediation by NO. Thus, endogenous NO produced by GCECs may modulate TGF-beta production by both GCECs and MCs and act to suppress matrix protein synthesis by MCs.

Transesophageal echocardiography during removal of central venous catheter associated with thrombus in superior vena cava.

Thrombosis of upper extremity veins and superior vena cava (SVC) can occur in patients with indwelling central venous catheters. Contrary to earlier reports, pulmonary embolism (PE) can result from these thrombi, especially when they are attached to catheters (sleeve thrombi) in contrast to venous wall (mural thrombi). Removal of catheters may be required when sepsis occurs or to reduce risk of sepsis when lines have been left in for several days. We describe two patients with thrombi in SVC related to central venous catheters in whom transesophageal echocardiography (TEE) was performed during catheter removal to monitor for thrombus dislodgement. TEE may have a role in showing thrombus dislodgement and embolization during removal of venous catheters complicated by SVC thrombi. Direct visualization of thrombus dislodgement may aid in early diagnosis of PE because signs and symptoms of PE are often missed or mistaken for underlying cardiopulmonary disease. TEE may also play a role in implementing appropriate treatment in patients with PE who show right ventricular strain.

Thromboxane/prostaglandin endoperoxide-induced hypertrophy of rat vascular smooth muscle cells is signaled by protein kinase C-dependent increases in transforming growth factor-beta.

In the present study, we examined the effect of the thromboxane/prostaglandin endoperoxide analogue U46619 on proliferation and hypertrophy in cultured rat vascular smooth muscle cells and the roles of protein kinase C and transforming growth factor-beta (TGF-beta) in the mediation of the hypertrophic response to U46619. Since an increase in basic fibroblast growth factor (bFGF) was previously shown to mediate the hypertrophic response to U46619, we also assessed the relationship between bFGF and TGF-beta in the expression of U46619 actions. U46619 increased [35S]methionine incorporation into protein and protein content of vascular smooth muscle cells but had no effect on cell number. A role for TGF-beta was supported by the following observations: (1) exogenous human TGF-beta 1 increased protein synthesis; (2) antibody to TGF-beta blocked both TGF-beta- and U46619-induced increases in protein content; (3) U46619 increased active and total TGF-beta bioactivities; and (4) the actions of U46619 on protein content and TGF-beta bioactivity were blocked by the thromboxane/prostaglandin endoperoxide receptor antagonist SQ 29,548. Previous observations had demonstrated a role for bFGF in the expression of U46619 actions on protein synthesis. Results of the present study suggest that TGF-beta and bFGF interact in mediating the protein synthetic response to U46619. First, the concentration of exogenous TGF-beta (10 pmol/L) alone required to produce a protein synthetic response equivalent to that induced by U46619 was much higher than the concentration of endogenous active TGF-beta that accumulated in the media in response to U46619 (0.7 pmol/L). Second, bFGF (20 ng/mL) increased total TGF-beta bioactivity and stimulated protein synthesis. The hyper-trophic response to bFGF was blocked by anti-TGF-beta. The ability of U46619 and bFGF to increase protein synthesis and protein content in vascular smooth muscle cells was associated with TGF-beta-induced suppression of proliferation, as evidenced by the ability of antibody to TGF-beta to enhance U46619- and bFGF-induced increases in [3H]thymidine incorporation into DNA. Results of the present study also supported a role for protein kinase C in the expression of U46619 and bFGF actions. U46619 increased protein kinase C activity in the particulate fraction of vascular smooth muscle cells. Moreover, the protein kinase C inhibitors GF109203X and staurosporine blocked U46619- and bFGF-induced increases in protein synthesis as well as active and total TGF-beta bioactivities. By contrast, the protein kinase C inhibitors did not prevent the increases in protein synthesis induced by exogenous TGF-beta. The results demonstrate that thromboxane/prostaglandin endoperoxide signals increased TGF-beta bioactivity via protein kinase C. Increases in both bFGF and TGF-beta are required for an optimal hypertrophic response to U46619. The hypertrophic response to TGF-beta occurs through a protein kinase C-independent pathway.

Nitric oxide suppresses increases in mesangial cell protein kinase C, transforming growth factor beta, and fibronectin synthesis induced by thromboxane.

Thromboxane (TX) stimulation of fibronectin (FN) synthesis in mesangial cells (MC) is dependent on protein kinase C (PKC)-mediated increases in transforming growth factor beta (TGF beta), and is suppressed by increases in cellular cGMP. The current studies evaluate the role of cGMP-dependent and -independent actions of nitric oxide (NO) in modulating the responses of MC to the TX analogue U46619. TX-stimulated increases in PKC activity, TGF beta, and FN synthesis in MC were suppressed by either 8-Br-PET-cGMP or the NO donor S-nitroso-N-acetylpenicillamine (SNAP). By contrast, NO, but not cGMP, inhibited basal PKC activity, TGF beta bioactivity and FN synthesis. The cGMP-dependent protein kinase 1-alpha inhibitor 8-(4-chlorophenylthio)guanosine 3',5'-cyclic monophosphorothioate (Rp) restored the PKC, TGF beta, and the FN synthetic responses to TX when added to MC before exposure of the cells to either cGMP or SNAP. However, neither Rp nor the guanylate cyclase inhibitor Ly83583 significantly altered SNAP inhibition of basal PKC. In addition, Rp failed to alter the decreases in basal TGF beta bioactivity and FN synthesis seen in the presence of SNAP. In contrast to the FN response to U46619, cGMP and SNAP did not affect the stimulation of FN synthesis by exogenous TGF beta. The later findings are consistent with inhibitory actions of NO and cGMP at, or proximal to, U46619-induced increases in TGF beta in the suppression of TX-signaled increases in FN synthesis. Thus, NO depresses basal PKC and TGF beta bioactivity in MC by mechanisms that are largely independent of cGMP, whereas NO inhibition of these MC responses to TX is mediated primarily by increases in cGMP and activation of protein kinase 1-alpha.

Unusual presentation of late regional cardiac tamponade after aortic surgery.

Localized pericardial effusion leading to cardiac tamponade is seen occasionally in patients after cardiac surgery. This condition may be difficult to diagnose clinically because of unusual presenting symptoms and absence of conventional signs of cardiac tamponade. A case of localized pericardial effusion with presenting symptoms of fever and increasing fatigue is described in this study. The definitive diagnosis was made using transesophageal echocardiography. Surgical drainage of localized effusion resulted in prompt hemodynamic and symptomatic improvement.

An assessment of galactic cosmic radiation quality considering heavy ion track structures within the cellular environment.

Beyond the magnetic influence of the Earth, the flux of galactic cosmic radiation (GCR) represents a radiological concern for long-term manned space missions. Current concepts of radiation quality and equivalent dose are inadequate for accurately specifying the relative biological "efficiency" of low doses of such heavily ionising radiations, based as they are on the single parameter of Linear Energy Transfer (LET). Such methods take no account of the mechanisms, nor of the highly inhomogeneous spatial structure, of energy deposition in radiation tracks. DNA damage in the cell nucleus, which ultimately leads to the death or transformation of the cell, is usually initiated by electrons liberated from surrounding molecules by the incident projectile ion. The characteristics of these emitted "delta-rays", dependent primarily upon the charge and velocity of the ion, are considered in relation to an idealised representation of the cellular environment. Theoretically calculated delta-ray energy spectra are multiplied by a series of weighting algorithms designed to represent the potential for DNA insult in this environment, both in terms of the quantity and quality of damage. By evaluating the resulting curves, and taking into account the energy spectra of heavy ions in space, a relative measure of the biological relevance of the most abundant GCR species is obtained, behind several shielding configurations. It is hoped that this method of assessing the radiation quality of galactic cosmic rays will be of value when considering the safety of long-term manned space missions.