Maternal and procedural factors associated with estimated blood loss in second trimester surgical uterine evacuation: a retrospective cohort analysis.

BACKGROUND: Prior studies examining bleeding with uterine evacuation have focused on high-volume centers performing over 1100 procedures annually. The aim of this study was to examine associations between blood loss and patient and procedural characteristics in a center performing fewer than 50 procedures annually. METHODS: This retrospective cohort study, with institutional review board approval, utilized procedural codes to identify patients undergoing uterine evacuation procedures between 14 weeks' and 24 weeks' gestational age across a 50-month period. The primary outcome was estimated blood loss; secondary outcomes were hemorrhage, transfusion and hospital re-admission. Associations between blood loss and other variables were examined using linear regression models. RESULTS: Charts of 161 women met inclusion criteria. Median estimated blood loss was 400 mL (IQR 300 mL) with 37% of patients having blood loss of ≥500 mL. In univariate analyses, increased blood loss was associated with later gestational age (P <0.001) and pregnancy termination (P <0.001). In a multiple linear regression model, both remained significant. Each one-week increase in gestational age was associated with a 7.1% mean increase in estimated blood loss (95% CI 2.47% to 11.9%; P=0.003). Patients whose uterine evacuation was indicated for pregnancy termination had an 80.6% increase in blood loss compared with those with pre-operative fetal demise (95% CI 37.5% to 137.2%; P <0.001). Rates of peri-operative transfusion and re-admission for bleeding were <4%. CONCLUSION: While blood loss may be greater in low volume centers, our transfusion and re-admission rates were low following second trimester uterine evacuation.

Structural and Volumetric Brain MRI Findings in Mild Traumatic Brain Injury.

BACKGROUND AND PURPOSE: Routine MR imaging findings are frequently normal following mild traumatic brain injury and have a limited role in diagnosis and management. Advanced MR imaging can assist in detecting pathology and prognostication but is not readily available outside research settings. However, 3D isotropic sequences with ∼1-mm3 voxel size are available on community MR imaging scanners. Using such sequences, we compared radiologists' findings and quantified regional brain volumes between a mild traumatic brain injury cohort and non-brain-injured controls to describe structural imaging findings associated with mild traumatic brain injury. MATERIALS AND METHODS: Seventy-one military personnel with persistent symptoms and 75 controls underwent 3T MR imaging. Three neuroradiologists interpreted the scans using common data elements. FreeSurfer was used to quantify regional gray and white matter volumes. RESULTS: WM hyperintensities were seen in 81% of the brain-injured group versus 60% of healthy controls. The odds of ≥1 WM hyperintensity in the brain-injured group was about 3.5 times the odds for healthy controls (95% CI, 1.58-7.72; P = .002) after adjustment for age. A frontal lobe-only distribution of WM hyperintensities was more commonly seen in the mild traumatic brain injury cohort. Furthermore, 7 gray matter, 1 white matter, and 2 subcortical gray matter regions demonstrated decreased volumes in the brain-injured group after multiple-comparison correction. The mild traumatic brain injury cohort showed regional parenchymal volume loss. CONCLUSIONS: White matter findings are nonspecific and therefore a clinical challenge. Our results suggest that prior trauma should be considered in the differential diagnosis of multifocal white matter abnormalities with a clinical history of mild traumatic brain injury, particularly when a frontal predilection is observed.

Impact of Ketorolac on Opioid Consumption after Knee Arthroscopy.

PURPOSE: The objective of this study was to examine postoperative opioid consumption in outpatients undergoing knee arthroscopy after a single dose of intravenous ketorolac. METHODS: Patients ages 18-65 years old, weighing over 50kg and scheduled for knee arthroscopy were randomized to one of the four groups of preoperative ketorolac (0mg, 7.5mg, 15mg, 30mg). The primary outcome measured was postoperative opioid consumption. Secondary outcomes included visual analog scale pain scores, patient satisfaction scores, side effects and total postoperative anesthesia care unit time. Equivalency between ketorolac groups in opioid reduction relative to placebo was evaluated for each dose pair (7.5 vs. 15mg, 7.5 vs. 30mg, and 15 vs. 30mg). Linear regression models were used to examine associations between ketorolac dose with postoperative length of stay and patient satisfaction. A linear mixed model was used to evalaute the association between ketorolac dose and pain scores over time. RESULTS: A total of 112 patients with comparable patient and procedural characteristics were enrolled. Equivalency in opioid reduction relative to placebo was not demonstrated between any examined ketorlac doses (7.5 vs. 15mg, P = 0.167; 7.5 vs. 30mg, P = 0.451; 15 vs. 30mg, P = 0.515). Compared to placebo, all ketorlac doses decreased postoperative pain scores (global P=0.012). Patient satisfaction and postoperative duration did not vary with ketorolac dose. CONCLUSIONS: Although all ketorolac doses decreased PACU pain scores, equivalency in PACU opioid reduction between ketorolac doses was not demonstrated.

Effect of Intraoperative Phenylephrine Infusion on Redistribution Hypothermia During Cesarean Delivery Under Spinal Anesthesia.

An observational clinical study to evaluate the effect of phenylephrine infusion on maternal temperatures during scheduled cesarean delivery under spinal anaesthesia was conducted in 40 ASA physical status II parturients. Following placement of spinal anesthesia, phenylephrine infusion was initiated at 40 µg/min and titrated to maintain mean arterial pressure within 20 percent of baseline. Maternal oral temperature, heart rate, and blood pressure were measured at baseline, spinal placement, every 10 minutes thereafter for 60 minutes. Phenylephrine dose received was documented every ten minutes. The range in maternal temperature change was 0.06-0.29°C. The lowest recorded temperature was 36.3°C. Decreased maternal temperature was associated with duration of anesthesia and cumulative phenylephrine dose in a univariate model (P<0.001 for all). The multivariable model showed an association between a greater decrease in maternal temperature with larger doses of phenylephrine being administered.

A simple but precise method for quantitative measurement of the quality of the laser focus in a scanning optical microscope.

We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic-scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light-collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, a beam profile in the form of an error function can be obtained and by repeating this with the knife edge at different axial positions relative to the beam waist, the divergence and astigmatism of the postobjective laser beam can be obtained. The measured divergence can be used to quantify how much of the full numerical aperture of the lens is used in practice. We present data of the beam radius, beam divergence, ellipticity and astigmatism obtained with low (0.15, 0.7) and high (1.3) numerical aperture lenses and lasers commonly used in confocal and multiphoton laser scanning microscopy. Our knife-edge method has several advantages over alternative knife-edge methods used in microscopy including that the knife edge is easy to prepare, that the beam can be characterized also directly under a cover slip, as necessary to reduce spherical aberrations for objectives designed to be used with a cover slip, and it is suitable for use with commercial laser scanning microscopes where access to the laser beam can be limited.

A review of recent experiments on step-to-step "hand-off" of the DNA intermediates in mammalian base excision repair pathways.

The current "working model" for mammalian base excision repair involves two sub-pathways termed single-nucleotide base excision repair and long patch base excision repair that are distinguished by their repair patch sizes and the enzymes/co-factors involved. These base excision repair sub-pathways are designed to sequester the various DNA intermediates, passing them along from one step to the next without allowing these toxic molecules to trigger cell cycle arrest, necrotic cell death, or apoptosis. Although a variety of DNA-protein and protein-protein interactions are known for the base excision repair intermediates and enzymes/co-factors, the molecular mechanisms accounting for step-to-step coordination are not well understood. In this review, we explore the question of whether there is an actual step-to-step "hand-off" of the DNA intermediates during base excision repair in vitro. The results show that when base excision repair enzymes are pre-bound to the initial single-nucleotide base excision repair intermediate, the DNA is channeled from apurinic/apyrimidinic endonuclease 1 to DNA polymerase beta and then to DNA ligase. In the long patch base excision repair sub-pathway, where the 5'-end of the incised strand is blocked, the intermediate after polymerase beta gap filling is not channeled from polymerase beta to the subsequent enzyme, flap endonuclease 1. Instead, flap endonuclease 1 must recognize and bind to the intermediate in competition with other molecules.

Apurinic/apyrimidinic (AP) site recognition by the 5'-dRP/AP lyase in poly(ADP-ribose) polymerase-1 (PARP-1).

The capacity of human poly(ADP-ribose) polymerase-1 (PARP-1) to interact with intact apurinic/apyrimidinic (AP) sites in DNA has been demonstrated. In cell extracts, sodium borohydride reduction of the PARP-1/AP site DNA complex resulted in covalent cross-linking of PARP-1 to DNA; the identity of cross-linked PARP-1 was confirmed by mass spectrometry. Using purified human PARP-1, the specificity of PARP-1 binding to AP site-containing DNA was confirmed in competition binding experiments. PARP-1 was only weakly activated to conduct poly(ADP-ribose) synthesis upon binding to AP site-containing DNA, but was strongly activated for poly(ADP-ribose) synthesis upon strand incision by AP endonuclease 1 (APE1). By virtue of its binding to AP sites, PARP-1 could be poised for its role in base excision repair, pending DNA strand incision by APE1 or the 5'-dRP/AP lyase activity in PARP-1.

Factors influencing cesarean delivery operative times: a prospective observational cohort study.

BACKGROUND: This study aimed to determine the distribution of operative delivery times for uncomplicated parturients undergoing elective cesarean delivery with neuraxial anesthesia. A secondary aim was to explore patient and surgical factors associated with longer cesarean delivery times. METHODS: A prospective observational study of 331 parturients undergoing elective cesarean delivery with neuraxial anesthesia was conducted. Factors examined included age, body mass index, ethnicity, number of previous cesarean deliveries, stretch mark and scar severity and surgical experience. RESULTS: Operative times ranged from 13 to 108 min with a mean (SD) of 43.4 (±15.7) min. Only 6 (1.8%) parturients had operative times >90 min and none were converted to general anesthesia. As the number of previous cesarean deliveries increased, the mean operative time increased linearly from 39.5 (±13.0) min in subjects with no previous cesarean deliveries to 52.8 (±18.1) min in subjects with 3 or 4 previous cesarean deliveries (P<0.0005). For parturients with previous cesarean deliveries, operative times were longer for those with scar scores > or =5 than for those with scores <5 (P<0.01). Stretch mark scores were not associated with operative times. Tubal ligation prolonged the total operative time by a mean of 7 min (P<0.0005), and attending staff required a mean of 6 more min than residents or fellows (P<0.01). There was no correlation between operative times, age and body mass index and little variation with ethnicity. CONCLUSIONS: These findings identify previous cesarean deliveries, increased scar intensity, tubal ligation and surgical experience as factors that increase operative times for cesarean delivery. The data also suggest that neuraxial anesthesia lasting 90 min should provide adequate analgesia for most uncomplicated parturients undergoing elective cesarean delivery.

Long-term clinical follow-up of sirolimus-eluting (CYPHER) coronary stents in the treatment of instent restenosis in an unselected population.

Randomised trials in a highly selected patient population have demonstrated a dramatic reduction in the incidence of in-stent restenosis (ISR) following implantation of sirolimus-eluting (S-E) Cypher coronary stents compared with bare metal stents (BMS). The clinical outcome following implantation of S-E stents for treatment of complex, unselected BMS ISR is less well defined. The aim of this study was to assess the safety and efficacy of S-E coronary stents in the treatment of an unselected population of BMS ISR. All patients who received S-E stents for treatment of BMS ISR from May 1 2002-November 30 2003 at a single institution were entered into a prospectively collected database. In-hospital and long-term outcomes were collected. Sixty patients were identified who received S-E stents for the treatment of ISR. Four patients (6%) had undergone previous brachytherapy and 22% were diabetic. The most common target vessel was the left anterior descending coronary artery (40%), and 6% of lesions were in saphenous vein grafts (SVGs). The mean reference diameter was 2.67+/-0.52 (range 1.75-4.0) mm and the mean lesion length was 16.22+/-11.46 (range 3-68) mm. There were no procedural or in-hospital major adverse cardiac events (MACE). Long-term follow-up was available in 59 patients (98%). The 12-month MACE rate (cardiac death, myocardial infarction or target lesion revascularisation) was 12% with a 7% percutaneous coronary intervention rate and a 7% coronary artery bypass graft rate. There were no cardiac deaths and two non-cardiac deaths. Of the seven patients who had clinical restenosis at 12 months, four had previously failed brachytherapy and three involved SVGs. In conclusion, the use of S-E stents appears safe and efficacious in the treatment of an unselected population of BMS ISR with results comparing favourably with historical controls. Further randomised studies are needed to delineate the optimal management of this high risk group of patients.

Clinical follow-up of paclitaxel-eluting (TAXUS) stents for the treatment of saphenous vein graft disease.

BACKGROUND: Randomized trials in selected patient populations have demonstrated dramatic reductions in the incidence of in-stent restenosis (ISR) following implantation of paclitaxel-eluting (PE) coronary stents compared with bare metal stents in native coronary disease. The clinical outcome following implantation of PE stents for saphenous vein graft (SVG) stenosis is largely unknown. AIM: To assess the safety and efficacy of PE coronary stents for the treatment of SVG stenosis in an unselected population. METHODS: All patients who received PE stents for the treatment of SVG disease from May 1, 2003, to May 1, 2005, were entered into a prospectively collected database. Fifty-five patients were identified with 69 lesions. In-hospital and late major adverse cardiac events (MACE) including death, myocardial infarction (MI), and target lesion revascularization (TLR) were recorded as well as the rate of target vessel revascularization (TVR). RESULTS: Mean follow-up was 13 months with 54 of the 55 patients contacted. The number of stents implanted was 1.12 +/- 0.37 per lesion and 1.38 +/- 0.59 per patient. Clinically significant procedural MACE was 0%. The late MACE rate was 9% with a 2% clinically driven TLR, a 4% coronary artery bypass graft (CABG), and a 4% TVR rate. There were four deaths, two cardiac and two noncardiac. CONCLUSION: PE stents appear safe and effective in the treatment of SVG disease at a mean follow-up time of 13 months. Randomized studies are needed to further delineate the optimal management of this high-risk group.

Long-term follow-up of renal artery stenting in an Australian population.

BACKGROUND: Renal artery stenosis comprises both atherosclerotic renovascular disease and fibromuscular dysplasia, and may be associated with refractory hypertension, acute 'flash' pulmonary oedema and renal failure. The long-term clinical effects of renal artery stenting remain unclear. AIM: To assess the procedural and long-term safety and efficacy of renal artery stenting and its effect on blood pressure, antihypertensive medication usage and serum creatinine. METHODS: All patients referred for renal artery stenting at our institution between September 1997 and December 2003 were entered into a prospectively collected database. Systolic and diastolic blood pressure, number of antihypertensive medications, serum creatinine and estimated glomerular filtration rate (eGFR) were recorded. Patients were followed-up at least six months post-procedure. RESULTS: Eighty-nine patients underwent renal arteriography, with 110 stents deployed in 102 lesions. The procedural success rate was 99% with no procedural mortality. There were two cases of peri-procedural haemorrhage and one of sepsis. One patient developed renal and peripheral atheroemboli. FOLLOW-UP: Mean follow-up was 28 months (range 6 months-7 years). Eight patients were lost to follow-up. There were nine deaths with a mean time to death of 20.7 months (range 12 months-3 years). There was a highly statistically significant fall in systolic blood pressure (BP) from 161.7+/-29.5 mmHg pre-procedure to 138.7+/-17.9 mmHg at long-term follow-up post-procedure (p<0.0001). The clinical restenosis rate was 6.2%. Renal function and eGFR remained stable and there was a borderline significant decrease in the number of antihypertensive medications used (p=0.05). CONCLUSION: Renal artery stenting is safe and appears effective for the treatment of clinically significant renal artery stenosis.

Comparative outcomes of percutaneous coronary interventions in diabetics vs non-diabetics with prior coronary artery bypass grafting.

AIMS: To determine the influence of diabetes on outcome after percutaneous coronary intervention in patients with prior coronary artery bypass grafting. METHODS AND RESULTS: Patients with prior coronary artery bypass grafting undergoing percutaneous coronary intervention from 1 January 1996, to 31 August 2000, were divided into two groups based on whether or not they had diabetes, excluding patients with acute infarction or shock. Cox proportional hazards models were utilized to estimate the association between diabetes and adverse events. One thousand one hundred and fifty-three post-coronary artery bypass grafting percutaneous coronary intervention patients were identified (326 diabetics and 827 non-diabetics). Diabetics were younger, more likely to have hypertension, heart failure, and lower ejection fraction. Procedural characteristics and angiographic and procedural success rates were similar. Diabetes was associated with increased mortality (hazard ratio 1.58, 95% confidence intervals 1.10-2.27). Diabetes did not have a significant effect on mortality in patients treated for single-territory coronary disease (hazard ratio 1.44, 95% confidence intervals 0.69-3.02), but did in patients with multi-territory disease (hazard ratio 1.79, 95% confidence intervals 1.16-2.76). However, in diabetics with multi-territory disease who were completely revascularized with percutaneous coronary intervention, mortality was comparable to non-diabetics (hazard ratio 1.32, 95% confidence intervals 0.57-3.03). CONCLUSION: Among percutaneous coronary intervention patients with prior coronary artery bypass grafting, diabetes portends an adverse prognosis.

Relationship between base excision repair capacity and DNA alkylating agent sensitivity in mouse monocytes.

Base excision repair (BER) capacity and the level of DNA polymerase beta (beta-pol) are higher in mouse monocyte cell extracts when cells are treated with oxidative stress-inducing agents. Consistent with this, such treated cells are more resistant to the cytotoxic effects of methyl methanesulfonate (MMS), which produces DNA damage considered to be repaired by the BER pathway. In contrast to the up-regulation of BER in oxidatively stressed cells, cells treated with the cytokine interferon-gamma (IFN-gamma) are down-regulated in both BER capacity of the cell extract and level of beta-pol. We find that cells treated with IFN-gamma are more sensitive to MMS than untreated cells. These results demonstrate concordance between beta-pol level, BER capacity and cellular sensitivity to a DNA methylation-inducing agent. The results suggest that BER is a significant defense mechanism in mouse monocytes against the cytotoxic effects of methylated DNA.

Influence of coronary thrombus on outcome of percutaneous coronary angioplasty in the current era (the Mayo Clinic experience).

Earlier studies documented an increased risk of percutaneous coronary intervention (PCI) in patients with angiographic evidence of thrombus. With newer antiplatelet agents and stents, it is not known whether thrombus is a risk factor after PCI. This study examines whether outcome of PCI in patients with thrombus has improved, and whether thrombus is associated with adverse outcome after PCI in the current era. This single-institution retrospective analysis of PCI in 7,184 patients was divided into 2 periods: group I, 1990 to 1995 (n = 3,640), and group II, 1996 to 1999 (n = 3,544). The groups were subdivided according to the presence or absence of angiographic thrombus before PCI. We compared the outcome of PCI for patients with and without thrombus in group II. A comparison was made in the 2 groups in patients with angiographic thrombus. Procedural success improved in group II compared with group I patients with thrombus (93% vs 88%, p <0.001). There was significant reduction in abrupt closure in the recent era in patients with thrombus (4% vs 7%, p = 0.01). In group II, procedural success remained lower in patients with (93% vs 96%) than without thrombus (p <0.001). After adjusting for the significant univariate characteristics of group II patients, thrombus remained an independent predictor of Q-wave infarction (odds ratio 3.78; 95% confidence interval [CI], 1.8 to 8.0; p <0.0013) and the composite end point of death, Q-wave infarction, and emergency bypass surgery (odds ratio 2.37; 95% CI 1.4 to 4.1; p = 0.002). There was a trend toward increased in-hospital death among patients with thrombus (odds ratio 2.06; 95% CI 0.9 to 4.8; p = 0.09). The 1-year outcome after successful PCI was similar for those with and without thrombus. Despite improvement in the outcome of patients with thrombus undergoing PCI in recent years, thrombus is still an independent predictor of adverse in-hospital outcomes after PCI.

Identification of MAL2, a novel member of the mal proteolipid family, though interactions with TPD52-like proteins in the yeast two-hybrid system.

The TPD52 (tumor protein D52)-like proteins are small coiled-coil motif-bearing proteins which were first identified though their expression in human breast carcinoma. TPD52-like proteins are known to interact in hetero-and homomeric fashions, but there are no known heterologous binding partners for these proteins. We now report the cloning of a novel member of the MAL proteolipid family, named MAL2, though its interaction with a TPD52L2 bait in a yeast two-hybrid screen. MAL2 is predicted to be 176 residues (19 kDa) with four transmembrane domains and is 35.8% identical to MAL, a proteolipid required in apical vesicle transport. The MAL2 prey bound all TPD52-like baits tested in the yeast two-hybrid system and in vitro translation of MAL2 produced a single 19-kDa (35)S-labeled protein which specifically bound full-length GST-Tpd52 in GST pull-down assays. The gene MAL2, which was localized to human chromosomal band 8q23 and shown to consist of four exons, is predominantly expressed in human kidney, lung, and liver. Our study has therefore identified a novel member of the MAL proteolipid family and potentially implicates TPD52-like proteins in vesicle transport.

DNA lesion bypass polymerases open up.

Structures of catalytic fragments of two DNA lesion bypass DNA polymerases, yeast DNA polymerase eta and an archeon DinB homolog, have recently been solved. These structures share several common architectural and structural features observed in other DNA polymerases, including a hand-like architecture with fingers, palm, and thumb subdomains. The new structures provide the first structural insights into DNA lesion bypass. The fingers and thumb are smaller than those in other DNA polymerases. Modeled substrates suggest that the fingers in the vicinity of the incoming nucleotide is closed, a conformation not previously observed for an unliganded polymerase. However, the template binding pocket appears to be more open, indicating that for DNA polymerase eta, a covalently linked thymine-thymine dimer could be accommodated.

Mammalian DNA beta-polymerase in base excision repair of alkylation damage.

DNA beta-polymerase (beta-pol) carries out two critical enzymatic reactions in mammalian single-nucleotide base excision repair (BER): DNA synthesis to fill the repair patch and lyase removal of the 5'-deoxyribose phosphate (dRP) group following cleavage of the abasic site by apurinic/apyrimidinic (AP) endonuclease (1). The requirement for beta-pol in single-nucleotide BER is exemplified in mouse fibroblasts with a null mutation in the beta-pol gene. These cells are hypersensitive to monofunctional DNA methylating agents such as methyl methane-sulfonate (MMS) (2). This hypersensitivity is associated with an abundance of chromosomal damage and induction of apoptosis and necrotic cell death (3). We have found that beta-pol null cells are defective in repair of MMS-induced DNA lesions, consistent with a cellular BER deficiency as a causative agent in the observed hypersensitivity. Further, the N-terminal 8-kDa domain of beta-pol, which contains the dRP lyase activity in the wild-type enzyme, is sufficient to reverse the methylating agent hypersensitivity in beta-pol null cells. These results indicate that lyase removal of the dRP group is a pivotal step in BER in vivo. Finally, we examined MMS-induced genomic DNA mutagenesis in two isogenic mouse cell lines designed for study of the role of BER. MMS exposure strongly increases mutant frequency in beta-pol null cells, but not in wild-type cells. With MMS treatment, beta-pol null cells have a higher frequency of all six base-pair substitutions, suggesting that BER plays a role in protecting the cell against methylation-induced mutations.

Modulation of retinal endothelial cell behaviour by insulin-like growth factor I and somatostatin analogues: implications for diabetic retinopathy.

Evidence suggests the involvement of growth hormone (GH), insulin-like growth factor I (IGF-I) and somatostatin in the pathology associated with diabetic retinopathy. We examined the effect of IGF-I on human retinal endothelial cell (HREC) survival following high glucose exposure and serum starvation, examined the signalling pathways mediating the protective effect of IGF-I on HREC, and characterized somatostatin receptor-induced retinal endothelial cell death. IGF-I (10 ng/ml) protected HREC from apoptosis induced by high glucose and serum starvation. Wortmannin, a specific inhibitor of phosphotidylinositol-3-kinase, blocks the ability of IGF-I to protect HREC from apoptosis. Incubation of HREC in serum-free medium caused a time-dependent increase in c-Jun N-terminal kinase (JNK) activity, and continuous culture of HREC in the presence of IGF-I or vascular endothelial growth factor (VEGF) prevented JNK activation and arrested apoptosis. Activation of tyrosine kinase receptors results in extracellular signal-related kinase (ERK) activation and activation of ERK is required for proliferation. Both IGF-I and VEGF produced a time- and concentration-dependent increase in the activation of ERK. Type 2 and type 3 somatostatin receptors have been implicated in cell-cycle arrest and apoptosis. Activation of the type 3 receptor in HREC resulted in cell death. These studies suggest that IGF-I is critical for HREC survival, and that somatostatin analogues acting through the type 3 receptor have direct effects on retinal endothelial cells. Furthermore, it appears that the therapeutic efficacy of somatostatin analogues lies not only in systemic inhibition of GH, but also in modulating local growth factor effects.

The effect of endothelin-1 on nuclear factor kappa B in macrophages.

Nuclear factor kappaB (NF-kappaB) is a transcriptional factor which may be pivotal in the pathogenesis of atherosclerosis. Endothelin-1 (ET-1) is a peptide with proatherogenic properties. We hypothesized that ET-1 may act through activation of NF-kappaB and degradation of IkappaB-alpha, the cytosolic inhibitor of NF-kappaB activation, to create an atherogenic environment. The human monocytic cell line THP-1 was stimulated with ET-1 +/- the ET antagonist, BQ788 and the proteosome inhibitor, PSI. LPS was used as a positive control. Gel shift assays for NF-kappaB activity and Western blot analysis for IkappaB-alpha were performed. Both LPS and ET-1 led to activation of NF-kappaB in nuclear extracts [3.4 +/- 0.45 (LPS) and 2.9 +/- 0.26 (ET-1) fold increase in Arbitrary Densitometric Units (ADU) compared with negative control (P < 0.005 in both cases)]. In the presence of the ETB antagonist, BQ788, NF-kappaB activation was attenuated and not different from control (1.7 +/- 0.24 fold DU compared with negative control; P = NS). In addition, both LPS and ET-1 mediated NF-kappaB activation were attenuated by preincubation with the proteosome inhibitor, PSI (1.3 +/- 0.58 and 1.1 +/- 0.3 fold increase in ADU compared with negative control respectively). Both LPS and ET-1 led to a decrease in the amount of IkappaB-alpha present in the THP-1 cytoplasmic extracts (2.1 +/- 1.5% and 54 +/- 15.7% of ADU vs negative control (P < 0.05). NF-kappaB is activated by ET-1 in human THP-1 monocytes. This data supports a role for the ETs in the development of inflammation in the vessel wall in atherosclerosis.