Macrophage and myofibroblast involvement in ischemic acute renal failure is attenuated by endothelin receptor antagonists

BACKGROUND: Endothelin (ET) may be a mediator of injury following ischemia-induced acute renal failure (ARF). ET receptor (ETR) antagonists have been reported to increase survival rates and lower serum creatinines when administered postrenal ischemia-reperfusion injury in the rat. Renal cellular and extracellular matrix responses to this therapy have not been addressed. METHODS: We investigated the use of ETR antagonists, PD 156707 (ETA) and SB 209670 (ETA and ETB) in the treatment of sublethal postischemic ARF. The right kidney of female Sprague-Dawley rats weighing approximately 200 g was removed. After five days, the left renal pedicle was occluded for 45 minutes. Twenty-four hours after renal ischemia, one of two ETR antagonists, PD 156707 (N = 7) or SB 209670 (N = 8), was administered. Experimental animals were compared with an ischemic group receiving only saline (N = 9). Three nephrectomized groups that did not undergo ischemia but that received infusions of saline (N = 6), PD 156707 (N = 6), and SB 209670 (N = 6), respectively, were also studied. Animals were sacrificed one week postischemia. Quantitation of monocytes and macrophages (Mo/Mphi), alpha-smooth muscle actin-positive myofibroblasts, and collagens type III and IV was performed by immunohistochemical staining. Cell kinetics were examined by staining for apoptosis with terminal deoxyuridine triphosphate (dUTP) nick end labeling and for proliferation with proliferating cell nuclear antigen. RESULTS: All ischemic groups of rats initially developed raised serum creatinine levels; however, no significant difference was observed between the groups (Kruskal-Wallis). Creatinines returned to preischemic values in all groups by the time of sacrifice. No significant difference in kidney weights or body weights was found between groups. Histologically, infiltration of Mo/Mphi was significantly reduced in groups treated with ETR antagonists (P < 0.001). The presence of myofibroblasts was also significantly reduced in the antagonist-treated groups (P < 0. 001). This was also paralleled by reduced quantities of collagen IV in the treated rat groups (P < 0.001). The interstitial area was also significantly greater in the saline group (P < 0.001). The amount of collagen III did not significantly differ between rat groups. Apoptosis was reduced (P < 0.001) by treatment with ETR antagonists, whereas proliferation was enhanced (P < 0.005). All non-ischemic groups showed no variation in any parameter studied at this time point. CONCLUSIONS: Treatment of ischemic ARF in the rat with ETR antagonists PD 156707 and SB 209670 attenuated cellular infiltration and matrix accumulation. An advantage of one antagonist over the other could not be determined in this study. The marked discrepancy between function and pathology (former unchanged, latter markedly improved) may be due to the time frame of this experiment, and longer outcome measures need to be assessed.     

The material basis for reduced mechanical properties in oim mice bones

Osteogenesis imperfecta (OI), a heritable disease caused by molecular defects in type I collagen, is characterized by skeletal deformities and brittle bones. The heterozygous and homozygous oim mice (oim/+ and oim/oim) exhibit mild and severe OI phenotypes, respectively, serving as controlled animal models of this disease. In the current study, bone geometry, mechanics, and material properties of 1-year-old mice were evaluated to determine factors that influence the severity of phenotype in OI. The oim/oim mice exhibited significantly smaller body size, femur length, and moment of area compared with oim/+ and wild-type (+/+) controls. The oim/oim femur mechanical properties of failure torque and stiffness were 40% and 30%, respectively, of the +/+ values, and 53% and 36% of the oim/+ values. Collagen content was reduced by 20% in the oim/oim compared with +/+ bone and tended to be intermediate to these values for the oim/+. Mineral content was not significantly different between the oim/oim and +/+ bones. However, the oim/oim ash content was significantly reduced compared with that of the oim/+. Mineral carbonate content was reduced by 23% in the oim/oim bone compared with controls. Mineral crystallinity was reduced in the oim/oim and oim/+ bone compared with controls. Overall, for the majority of parameters examined (geometrical, mechanical, and material), the oim/+ values were intermediate to those of the oim/oim and +/+, a finding that parallels the phenotypes of the mice. This provides evidence that specific material properties, such as mineral crystallinity and collagen content, are indicative and possibly predictive of bone fragility in this mouse model, and by analogy in human OI.     

Human cytochrome P4502B6: interindividual hepatic expression, substrate specificity, and role in procarcinogen activation

In situ hybridization was combined with serotonin (5-hydroxytryptamine, 5-HT) or tyrosine hydroxylase immunocytochemistry and with Fluoro-Gold retrograde labeling of bulbo-spinal pathways in order to investigate the expression of GAP-43 mRNA in monoamine cell groups of the adult rat brain stem. Consistent with previous reports, GAP-43 mRNA was observed in serotonin and dopamine cell groups in the pons. In addition, GAP-43 expressing cells were observed in all the major monoamine cell groups in the medulla. Thus the B1, B2 and B3 serotonin cell groups all showed high GAP-43 expression in all contained many GAP-43 expressing serotonin cells with spinal cord projections. The A1, A2, A5 and A6 noradrenaline cell groups also showed high GAP-43 expression, although cells with spinal cord projections were largely restricted to the A5 group and A6 subcoeruleus region. In all areas, GAP-43 expressing cells with spinal cord projections were also observed which were not serotonergic or noradrenergic.     

The impact of cardiology on the collective effective dose in the North of England

Two cardiology X-ray rooms were monitored with dose-area product meters as part of a Regional Patient Dosimetry Programme. Dose-area product measurements on over 2000 patients undergoing examinations in the cardiology rooms are presented. The data have been corrected according to patient size where possible. In room A mean dose-area product values for coronary angiography, coronary angioplasty, radiofrequency ablation and mitral valvuloplasty were found to be 47.7, 72.2, 91.1 and 161.9 Gy cm2 respectively. In room B mean dose-area product values for coronary angiography and coronary angioplasty were found to be 23.4 and 51.6 Gy cm2 respectively. Observational studies were used to deduce the typical projections and technique factors. This typical examination was used to simulate an angiogram from which it was possible to derive factors to convert measured dose-area product values into estimates of effective dose. In room A, the effective doses were estimated to be 9.4, 14.2, 17.3 and 29.3 mSv for coronary angiography, coronary angioplasty, radiofrequency ablation and mitral valvuloplasty, respectively. The effective doses during coronary angiography and coronary angioplasty, performed in room B, were found to be 4.6 and 10.2 mSv, respectively. A regional survey of the frequency of these cardiac procedures was performed. It was deduced that the annual collective effective dose from these cardiac procedures in the North of England, the former Northern Region, was 45.7 manSv.     

Contemporary percutaneous treatment of unprotected left main coronary stenoses: initial results from a multicenter registry analysis 1994-1996

BACKGROUND: Coronary artery bypass surgery (CABG) has been considered the therapy of choice for patients with unprotected left main (ULMT) coronary stenoses. Selected single-center reports suggest that the results of percutaneous intervention may now approach those of CABG. METHODS AND RESULTS: To assess the results of percutaneous ULMT treatment from a wide variety of experienced interventional centers, we requested data on consecutive patients treated after January 1, 1994, from 25 centers. One hundred seven patients were identified who were treated either electively (n=91) or for acute myocardial infarction (n=16). Of patients treated electively, 25% were considered inoperable, and 27% were considered high risk for bypass surgery. Primary treatment included stents (50%), directional atherectomy (24%), and balloon angioplasty (20%). Follow-up was 98.8% complete at 15+/-8 months. Results varied considerably, depending on presentation and treatment. For patients with acute myocardial infarction, technical success was achieved in 75%, and survival to hospital discharge was 31%. For elective patients, technical success was achieved in 98.9%, and in-hospital survival was strongly correlated with left ventricular ejection fraction (P=.003). Longer-term event (death, infarction, or bypass surgery) -free survival was correlated with ejection fraction (P<.001) and was inversely related to presentation with progressive or rest angina (P<.001). Surgical candidates with ejection fractions > or = 40% had an in-hospital survival of 98% and a 9-month event-free survival of 86+/-5%, whereas patients with ejection fractions < 40% had 67% and 22+/-12% in-hospital and 9-month event-free survivals, respectively. Nine hospital survivors (10.6%) experienced cardiac death within 6 months of hospital discharge. CONCLUSIONS: While results for selected patients appear promising, until early post-hospital discharge cardiac death can be better understood and minimized, percutaneous revascularization of ULMT stenosis should not be considered an alternative to bypass surgery for most patients. When percutaneous revascularization of ULMT is required, directional atherectomy and stenting appear to be the preferred techniques, and follow-up angiography 6 to 8 weeks after treatment is probably advisable.     

Three-dimensional ultrastructural analysis of the Saccharomyces cerevisiae mitotic spindle

The three dimensional organization of microtubules in mitotic spindles of the yeast Saccharomyces cerevisiae has been determined by computer-aided reconstruction from electron micrographs of serially cross-sectioned spindles. Fifteen spindles ranging in length from 0.6-9.4 microns have been analyzed. Ordered microtubule packing is absent in spindles up to 0.8 micron, but the total number of microtubules is sufficient to allow one microtubule per kinetochore with a few additional microtubules that may form an interpolar spindle. An obvious bundle of about eight interpolar microtubules was found in spindles 1.3-1.6 microns long, and we suggest that the approximately 32 remaining microtubules act as kinetochore fibers. The relative lengths of the microtubules in these spindles suggest that they may be in an early stage of anaphase, even though these spindles are all situated in the mother cell, not in the isthmus between mother and bud. None of the reconstructed spindles exhibited the uniform populations of kinetochore microtubules characteristic of metaphase. Long spindles (2.7-9.4 microns), presumably in anaphase B, contained short remnants of a few presumed kinetochore microtubules clustered near the poles and a few long microtubules extending from each pole toward the spindle midplane, where they interdigitated with their counterparts from the other pole. Interpretation of these reconstructed spindles offers some insights into the mechanisms of mitosis in this yeast.     

Stress fractures of the sacrum and lower extremity

Using the polymerase chain reaction (PCR) method, the rpsLd gene was amplified and cloned, which encodes the streptomycin-dependent (Smd) mutant of ribosomal protein S12 in E.coli T83. The result of DNA sequencing showed an AAA to CAA mutation at codon 42, leading to the substitution of glutamine (Gln, Q) for lysine (Lys, K). According to the principle of Garnier, we predicted that there might be alterations in the secondary structural propensity of protein S12 due to the mutation. The outcome indicated that the beta-turn propensity at position 42 and its nearby region was increased evidently and the relative position of relevant subdomains were changed. As a result, the special conformation of the whole protein S12 was influenced. In view of that ribosomal proteins and ribosomal RNAs (rRNA) mutually adapted in structures and functions, the probable molecular mechanism. That how protein S12 Smd mutant in E.coli T83 suppressed lambda N gene's expression is discussed.