[Treatment of typical hemolytic-uremic syndrome. Knowledge gained from analyses of the 2011 E. coli outbreak]. / Therapie des typischen hämolytisch-urämischen Syndroms. Erkenntnisse aus dem E.-coli-Ausbruch 2011.

Shiga toxin-associated hemolytic uremic syndrome (HUS) is an entity of thrombotic microangiopathy characterized by hemolytic anemia, thrombocytopenia, central nervous symptoms, and renal insufficiency. In May 2011, an outbreak of enterohemorrhagic Escherichia coli (EHEC; O104:H4) occurred in Northern Germany. By the end of July 2011, the outbreak was over but nearly 4000 patients had an EHEC infection, 855 cases of hemolytic-uraemic syndrome were reported to the Robert Koch Institute, and there were 35 (4.1%) deaths. Shiga toxin-induced HUS is a rare disease and no controlled clinical trials on therapeutic options are available. First analyses of this outbreak suggest that therapeutic plasma exchange, which was used in the majority of patients, had no benefit and might even be harmful. The role of eculizumab, a monoclonal antibody which inhibits the complement system, is being examined in a multicenter study: the results have not been published yet. Promising is the use of some antibiotics. This would change a paradigm that antibiotics should be avoided. Ongoing and future analyses of the epidemic should be awaited before a final recommendation regarding the different treatment strategies can be made.

Redox modulation of stress resilience by Crocus sativus L. for potential neuroprotective and anti-neuroinflammatory applications in brain disorders: From molecular basis to therapy.

Recent evidence demonstrates that Crocus sativus L. (saffron) counteracts oxidative stress, mitochondrial dysfunction and neuroinflammation, closely linked to initiation and progression of major brain pathologies. Interestingly, saffron constituents such as crocin, crocetin and safranal can exert antioxidant or toxic effects depending on their endogenous concentration. According to the hormesis principles, at low dose they act as antioxidants in a wide range of brain diseases by upregulating Nrf2 signaling pathway and the expression of vitagenes, such as NAD(P)H-quinone oxidoreductase (NQO1), glutathione transferase (GT), heme oxygenase-1 (HO-1), sirtuin-1 (Sirt1) and thioredoxin (Trx) system. Importantly, neuronal dysregulation of Nrf2 pathway can be a prominent cause of selective susceptibility, under neuroinflammatory conditions, due to the high vulnerability of brain cells to oxidative stress. Here we discuss natural inducers from saffron targeting Nrf2/vitagene pathway for development of new therapeutical strategies to suppress oxidative stress and neuroinflammation and consequently cognitive dysfunction. In this review we also focus on the hormetic effect of saffron active constituents, summarizing their neuroprotective and anti-neuroinflammatory properties, as well as pharmacological perspectives in brain disorders.

On the stability of thoriated tungsten cathodes in strong magnetic fields.

Thoriated tungsten cathodes, first studied by Langmuir [Phys. Rev. 22, 357-398 (1923)], are used in many applications as efficient electron emitters. However, neutral pressure gauges with thoriated tungsten cathodes (or ASDEX pressure gauges) are not reliable when operated in the strong magnetic field of fusion devices of several Tesla. We have identified the reason for the bad performance in the Wendelstein 7-X stellarator during the operation of several 100 s. Not only were slow, creeping mechanical deformations of the cathodes observed, but also fast events, such as sudden short circuits. The temperature of the cathode is often much higher (about 2400 K) than the maximum value recommended by Langmuir [Phys. Rev. 22, 357-398 (1923)] (about 1900 K). Our test in a superconducting magnet revealed that for a long-pulse operation of 30 min or more in a 3.1 T field, there is an additional effect. We observed that the cathodes required a very high heating current after 6 h of operation. As a consequence, the possible temperature range of the thoriated tungsten cathodes became very small near to an experimentally determined failure limit. In fusion devices with long-pulse operation or in reactors, new cathode types must be used. We give a brief overview of alternative designs that are currently under development.

Wisconsin In Situ Penning (WISP) gauge: A versatile neutral pressure gauge to measure partial pressures in strong magnetic fields.

A new type of in-vessel Penning gauge, the Wisconsin In Situ Penning (WISP) gauge, has been developed and successfully operated in the Wendelstein 7-X (W7-X) island divertor baffle and vacuum vessel. The capacity of the quantitative measurements of the neutral reservoir for light impurities, in particular, helium, is important for tokamaks as well as stellarator divertors in order to avoid fuel dilution and radiative energy loss. Penning gauges assisted by spectroscopy are a powerful tool to obtain the total neutral pressure as well as fractional neutral pressures of specific impurities. The WISP gauge is a miniaturized Penning gauge arrangement, which exploits the ambient magnetic field of magnetic confinement fusion experiments to establish the Penning discharge. Then, in situ spectroscopy is conducted to separate the fractional neutral pressures of hydrogen, helium, and possibly also other impurities. The WISP probe head was qualified using the magnetic field of the Magnetized Dusty Plasma Experiment at Auburn University between 0.25 T and 3.5 T [E. Thomas et al., J. Plasma Phys. 81, 345810206 (2015)]. The in-depth quantitative evaluation for hydrogen and helium will be shown as well as an exploration of nitrogen, argon, and neon. A power law scaling between current I and pressure p, I = f(Gas,V) · pn(Gas, B), was shown. The factor f is gas and anode potential dependent, while n is gas and magnetic field strength dependent. Pressure measurements from 0.1 mbar and down to 1 × 10-5 mbar were achieved, demonstrating a reliable operating range for relevant pressure levels in the divertor and main vessel regions in current and future fusion devices, with a time resolution of up to 1 kHz. The lowest achievable pressure measurement increases with an increase in B and can be shifted with the anode potential V. At W7-X, the WISP probe head was mounted on an immersion tube setup that passes through the cryostat and places the probe head close to the plasma. Two probe heads were positioned in different divertor pump gaps, top and bottom, and one close to the plasma on the midplane in one module. The gauges were in situ calibrated together with the ASDEX pressure gauges [G. Haas and H.-S. Bosch, Vacuum 51, 39 (1998)]. Data were taken during the entire operation phase 1.2b, and measurements were coherent with other neutral gas pressure gauges. For the spectroscopic partial pressure measurements, channels of a spectroscopic detection system based on photo-multipliers, a so-called filterscope [R. J. Colchin et al., Rev. Sci. Instrum. 74, 2068 (2003)], provided by the Oak Ridge National Lab were used.

First results from the implementation of the ITER diagnostic residual gas analyzer prototype at Wendelstein 7-X.

Fusion reactors and long pulse fusion experiments heavily depend on a continuous fuel cycle, which requires detailed monitoring of exhaust gases. We have used a diagnostic residual gas analyzer (DRGA) built as a prototype for ITER and integrated it on the most advanced stellarator fusion experiment, Wendelstein 7-X (W7-X). The DRGA was equipped with a sampling tube and assessed for gas time of flight sample response, effects of magnetic field on gas detection and practical aspects of use in a state of the art fusion environment. The setup was successfully commissioned and operated and was used to observe the gas composition of W7-X exhaust gases. The measured time of flight gas response was found to be in the order of a second for a 7 m sample tube. High values of magnetic field were found to affect the partial pressure readings of the DRGA and suggest that additional shielding is necessary in future experimental campaigns.

Rapid development of severe end-organ damage in C57BL/6 mice by combining DOCA salt and angiotensin II.

The C57BL/6 mouse strain serves as the genetic background of many transgenic and gene knockout models; however, this strain appears to be resistant to hypertension-induced renal injury. We developed a new model of hypertensive end-organ damage in C57BL/6 mice by combining deoxycorticosterone acetate (DOCA) and salt with angiotensin II infusion. The systolic blood pressure (SBP) was significantly elevated in DOCA salt-angiotensin II mice compared to control mice or mice treated individually with DOCA salt or angiotensin II. Hypertensive glomerular damage, increased expression of profibrotic and inflammatory genes, albuminuria, tubular casts, increased plasma cholesterol, cardiac hypertrophy, and fibrosis were found in mice treated with DOCA salt-angiotensin II. The SBP in the angiotensin II-infused group was further increased by increasing the infusion rate; only mild injury was observed in these mice, suggesting that blood pressure was not a causal factor. Removal of DOCA and the angiotensin pump lowered blood pressure to normal; however, albuminuria along with the glomerular and cardiac damage did not completely resolve. Our study describes a new model of hypertensive end-organ damage and repair in C57BL/6 mice.

Protective effects of soy-isoflavones in cardiovascular disease. Identification of molecular targets.

UNLABELLED: Epidemiological studies indicate that the consumption of soy-containing food may prevent or slow-down the development of cardiovascular disease. In endothelial cells application of a soy extract or a combination of the most abundant soy isoflavones genistein and daidzein both inhibited apoptosis, a driving force in atherosclerosis development, when applied in combination with oxidized LDL or homocysteine. Proteome analysis revealed that the stressor-induced alteration of protein expression profile was reversed by the soy extract or the genistein/daidzein mixture. Only few protein entities that could be functionally linked to mitochondrial dysfunction were regulated in common by both application forms of isoflavones. A dietary intervention with isoflavone-enriched soy extract in postmenopausal women, who generally show strongly increased cardiovascular risk due to diminished estrogen production, led to significant alterations in the steady state levels of proteins from mononuclear blood cells. The proteins identified by proteome analysis revealed that soy isoflavones may increase the anti-inflammatory response in blood mononuclear cells thereby contributing to the atherosclerosis-preventive activities of a soy-rich diet. CONCLUSION: By proteome analysis protein targets were identified in vitro in endothelial cells that respond to soy isoflavones and that may decipher molecular mechanisms through which soy products exert their protective effects in the vasculature.

An ionization pressure gauge with LaB6 emitter for long-term operation in strong magnetic fields.

We report here on a potentially significant improvement in the design of neutral pressure gauges of the so-called ASDEX-type which were first used in the Axially Symmetric Divertor EXperiment (ASDEX). Such gauges are considered state-of-the-art and are in wide use in fusion experiments, but they nonetheless suffer from a relatively high failure rate when operated at high magnetic field strengths for long times. This is therefore a significant concern for long-pulse, high-field experiments such as Wendelstein 7-X (W7-X) and ITER. The new design is much more robust. The improvement is to use a LaB6 crystal instead of a tungsten wire as the thermionic emitter of electrons in the gauge. Such a LaB6 prototype gauge was successfully operated for a total of 60 h in B = 3.1 T, confirming the significantly improved robustness of the new design and qualifying it for near-term operation in W7-X. With the LaB6 crystal, an order of magnitude reduction in heating current is achieved, relative to the tungsten filament based gauges, from 15-20 A to 1-2 A. This reduces the Lorenz forces and the heating power by an order of magnitude also and is presumably the reason for the much improved robustness. The new gauge design, test environment setup at the superconducting magnet, and results from test operation are described.

Analysis of Risk Factors for Allograft Outcome Comparing 2 Kidneys From the Same Donor in Separate Recipients.

BACKGROUND: An analysis of 2 kidney transplants from the same donor at the same center enables us to analyze the influence of risk factors on the outcome of the grafts in different recipients. METHODS: We retrospectively analyzed 88 kidneys from 44 donors that were implanted in 88 recipients at our institution between 2007-2016. We defined unsatisfactory outcome as glomerular filtration rate <30 mL/min/1.73 m2 allograft loss or recipient death within the first year after transplantation. Fifty-three kidneys were allocated and age-matched to donors above the age of 65 years (via Eurotransplant Senior Program or center offer). We compared kidney pairs with satisfactory outcome in both recipients (group A) to pairs with divergent outcome (group B) and unsatisfactory outcome in both recipients (group C). RESULTS: Thirty-four grafts (17 donors) had a satisfactory outcome for both recipients (group A), and 16 grafts (8 donors) had an unsatisfactory outcome for both recipients (group C). Donor age was significantly higher in group C vs group A (67.5 ± 6.7 vs 56.4 ± 16.0 years, P = .010). The 19 donors donating 1 kidney with satisfactory and the other with unsatisfactory outcome were 67.4 ± 10.7 years old (group B). A severe surgical complication occurred more often in recipients with an unsatisfactory outcome in comparison to patients with a satisfactory outcome. CONCLUSION: Donor age is an important risk factor for an unsatisfactory outcome, either in one or both kidneys of the same donor.

M2e-tetramer-specific memory CD4 T cells are broadly protective against influenza infection.

Matrix protein 2 ectodomain (M2e) is considered an attractive component of a broadly protective, universal influenza A vaccine. Here we challenge the canonical view that antibodies against M2e are the prime effectors of protection. Intranasal immunizations of Balb/c mice with CTA1-3M2e-DD-generated M2e-specific memory CD4 T cells that were I-Ad restricted and critically protected against infection, even in the complete absence of antibodies, as observed in JhD mice. Whereas some M2e-tetramer-specific memory CD4 T cells resided in spleen and lymph nodes, the majority were lung-resident Th17 cells, that rapidly expanded upon a viral challenge infection. Indeed, immunized IL-17A-/- mice were significantly less well protected compared with wild-type mice despite exhibiting comparable antibody levels. Similarly, poor protection was also observed in congenic Balb/B (H-2b) mice, which failed to develop M2e-specific CD4 T cells, but exhibited comparable antibody levels. Lung-resident CD69+ CD103low M2e-specific memory CD4 T cells were αß TCR+ and 50% were Th17 cells that were associated with an early influx of neutrophils after virus challenge. Adoptively transferred M2e memory CD4 T cells were strong helper T cells, which accelerated M2e- but more importantly also hemagglutinin-specific IgG production. Thus, for the first time we demonstrate that M2e-specific memory CD4 T cells are broadly protective.

ATP6AP2 over-expression causes morphological alterations in the hippocampus and in hippocampus-related behaviour.

The (pro)renin receptor [(P)RR], also known as ATP6AP2 [ATPase 6 accessory protein 2], is highly expressed in the brain. ATP6AP2 plays a role in early brain development, adult hippocampal neurogenesis and in cognitive functions. Lack of ATP6AP2 has deleterious effects, and mutations of ATP6AP2 in humans are associated with, e.g. X-linked intellectual disability. However, little is known about the effects of over-expression of ATP6AP2 in the adult brain. We hypothesized that mice over-expressing ATP6AP2 in the brain might exhibit altered neuroanatomical features and behavioural responses. To this end, we investigated heterozygous transgenic female mice and confirmed increased levels of ATP6AP2 in the brain. Our data show that over-expression of ATP6AP2 does not affect adult hippocampal neurogenesis, exercise-induced cell proliferation, or dendritic spine densities in the hippocampus. Only a reduced ventricular volume on the gross morphological level was found. However, ATP6AP2 over-expressing mice displayed altered exploratory behaviour with respect to the hole-board and novel object recognition tests. Moreover, primary adult hippocampal neural stem cells over-expressing ATP6AP2 exhibit a faster cell cycle progression and increased cell proliferation. Together, in contrast to the known deleterious effects of ATP6AP2 depletion, a moderate over-expression results in moderate behavioural changes and affects cell proliferation rate in vitro.

Activation of mesangial cells by the phosphatase inhibitor vanadate. Potential implications for diabetic nephropathy.

The metalion vanadate has insulin-like effects and has been advocated for use in humans as a therapeutic modality for diabetes mellitus. However, since vanadate is a tyrosine phosphatase inhibitor, it may result in undesirable activation of target cells. We studied the effect of vanadate on human mesangial cells, an important target in diabetic nephropathy. Vanadate stimulated DNA synthesis and PDGF B chain gene expression. Vanadate also inhibited total tyrosine phosphatase activity and stimulated tyrosine phosphorylation of a set of cellular proteins. Two chemically and mechanistically dissimilar tyrosine kinase inhibitors, genistein and herbimycin A, blocked DNA synthesis induced by vanadate. Vanadate also stimulated phospholipase C and protein kinase C. Downregulation of protein kinase C abolished vanadate-induced DNA synthesis. Thus, vanadate-induced mitogenesis is dependent on tyrosine kinases and protein kinase C activation. The most likely mechanism for the effect of vanadate on these diverse processes involves the inhibition of cellular phosphotyrosine phosphatases. These studies demonstrating that vanadate activates mesangial cells may have major implications for the therapeutic potential of vanadate administration in diabetes. Although vanadate exerts beneficial insulin-like effects and potentiates the effect of insulin in sensitive tissue, it may result in undesirable activation of other target cells, such as mesangial cells.

Angiotensin II stimulates expression of the chemokine RANTES in rat glomerular endothelial cells. Role of the angiotensin type 2 receptor.

Glomerular influx of monocytes/macrophages (M/M) occurs in many immune- and non-immune-mediated renal diseases. The mechanisms targeting M/M into the glomerulus are incompletely understood, but may involve stimulated expression of chemokines. We investigated whether angiotensin II (ANG II) induces the chemokine RANTES in cultured glomerular endothelial cells of the rat and in vivo. ANG II stimulated mRNA and protein expression of RANTES in cultured glomerular endothelial cells. The ANG II-induced RANTES protein was chemotactic for human monocytes. Surprisingly, the ANG II-stimulated RANTES expression was transduced by AT2 receptors because the AT2 receptor antagonists PD 123177 and CGP-42112A, but not an AT1 receptor blocker, abolished the induced RANTES synthesis. Intraperitoneal infusion of ANG II (500 ng/h) into naive rats for 4 d significantly stimulated glomerular RANTES mRNA and protein expression compared with solvent-infused controls. Immunohistochemistry revealed induction of RANTES protein mainly in glomerular endothelial cells and small capillaries. Moreover, ANG II- infused animals exhibited an increase in glomerular ED-1- positive cells compared with controls. Oral treatment with PD 123177 (50 mg/liter drinking water) attenuated the glomerular M/M influx without normalizing the slightly elevated systolic blood pressure caused by ANG II infusion, suggesting that the effects on blood pressure and RANTES induction can be separated. We conclude that the vasoactive peptide ANG II may play an important role in glomerular chemotaxis of M/M through local induction of the chemokine RANTES. The observation that the ANG II- mediated induction of RANTES is transduced by AT2 receptors may influence the decision as to which substances might be used for the therapeutic interference with the activity of the renin-angiotensin system.

Dietary flavone is a potent apoptosis inducer in human colon carcinoma cells.

Flavonoids are polyphenolic compounds that occur ubiquitously in plants. They are discussed to represent cancer preventive food components in a human diet that is rich in fruits and vegetables. To understand the molecular basis of the putative anticancer activity of flavonoids, we investigated whether and how the core structure of the flavones, 2-phenyl-4H-1-benzopyran-4-one (flavone) affects proliferation, differentiation, and apoptosis in HT-29 human colon cancer cells. Moreover, the effects of flavone in transformed epithelial cells were compared with those obtained in nontransformed primary mouse colonocytes. Proliferation, differentiation, and apoptosis in transformed as well as nontransformed colon cells were measured by fluorescence-based techniques. Apoptosis was also determined by changes in membrane permeability, FACScan analysis, and detection of DNA fragmentation. Semiquantitative reverse transcription PCR was performed to assess the effects of flavone on transcript levels. Flavone was found to reduce cell proliferation in HT-29 cells with an EC(50) value of 54.8 +/- 1.3 microM and to potently induce differentiation as well as apoptosis. The flavonoid proved to be a stronger apoptosis inducer than the clinically established antitumor agent camptothecin. The effects of flavone in HT-29 cells were associated with changed mRNA levels of cell-cycle- and apoptosis-related genes including cyclooxygenase-2 (COX-2), nuclear transcription factor kappaB (NF-kappaB), and bcl-X(L). Moreover, flavone, but not camptothecin, displayed a high selectivity for the induction of apoptosis and of growth inhibition only in the transformed colonocytes. In conclusion, the plant polyphenol flavone induces effectively programmed cell death, differentiation, and growth inhibition in transformed colonocytes by acting at the mRNA levels of genes involved in these processes. Because these genes play a crucial role in colon carcinogenesis, flavone may prove to be a potent new cytostatic compound with improved selectivity toward transformed cells.

Development of miniaturized, spectroscopically assisted Penning gauges for fractional helium and hydrogen neutral pressure measurements.

Direct measurements of the helium (He) fractional neutral pressure in the neutral gas around fusion devices is challenging because of the small mass difference between the abundant D2 molecules and the He ash which will be produced by deuterium-tritium fusion. To study He exhaust, an in situ Penning gauge system is being developed at UW-Madison that is optimized for good pressure and high spectroscopic sensitivity. Three different anode geometries have been studied regarding their vacuum electrostatic fields, light output, and ion current. The light output of the two new anode configurations are at least one order of magnitude above the currently available designs, hence improving the spectroscopic sensitivity at similar total neutral pressure resolution.

Binding proteins for cyclosomatostatins and bile acids in basolateral plasma membranes of rat liver.

The bile acids cholate and taurocholate on the one hand and the cyclopeptide c(Phe-Thr-Lys-Trp-Phe-D-Pro) (008), an analog of somatostatin with retro sequence, on the other hand, display mutually competitive transport inhibition into isolated rat hepatocytes. This indicates a common transport system for bile acids and cyclosomatostatins in sinusoidal rat liver plasma membranes. In order to identify and isolate common binding and/or transport proteins for bile acids and the cyclopeptides by affinity chromatography, the bile acid derivative 4'-amino-7-benzamidotaurocholate (ABATC) and the cyclosomatostatin-analog 008 were attached to a gel matrix. Two methods were used to prepare integral membrane proteins: (1) alkaline EDTA extraction and (2) Triton X-114 phase separation. Octyl glycoside solubilized, alkaline EDTA-extracted integral basolateral membrane proteins with apparent molecular masses of 52 and 48 kDa bound specifically to the ABATC affinity matrix. Two-phase Triton X-114 separated integral membrane proteins of the same molecular masses bound specifically to the cyclosomatostatin ligand. The 48 kDa ABATC and 008 binding protein was shown to be present in the basolateral plasma membrane fraction and in the microsomal fraction. The isolated 52 kDa ABATC binding protein was localized only in basolateral plasma membranes and could not be found in isolated microsomes.

Angiotensin II induces p27(Kip1) expression in renal tubules in vivo: role of reactive oxygen species.

Previous studies have demonstrated that angiotensin II (ANG II) mediates cell cycle arrest of cultured renal tubular cells by induction of p27(Kip1), an inhibitor of cyclin-dependent kinases. However, it is not known whether ANG II exerts similar effects in vivo. Infusion of ANG II into naive rats for 7 days increased formation of reactive oxygen species in tubular cells of the kidney. Furthermore, ANG II infusion stimulated protein expression of p27(Kip1) as detected by western blotting of tubular lysates and immunohistochemistry. Infusion of ANG II reduced tubular proliferation as detected by proliferating-cell nuclear antigen (PCNA) immunohistochemistry. The increase in p27(Kip1) expression was not due to an increase in mRNA. Immunoprecipitation experiments revealed that the increased p27(Kip1) protein associates with cyclin-dependent kinase 2. Coadministration of the radical scavenger dimethylthiourea abolished this ANG II mediated p27(Kip1) expression without reducing systemic blood pressure. Furthermore, dimethylthiourea infusion attenuates the ANG II mediated G(1)-phase arrest of tubular cells. However, infusion of norepinephrine did not induce reactive oxygen species or p27(Kip1) expression, despite a significant increase in blood pressure. Thus ANG II induces p27(Kip1) expression in renal tubular cells in vivo. This effect is mediated by reactive oxygen species. Since tubular hypertrophy depends on G(1)-phase arrest and may promote subsequent development of interstitial fibrosis, administering oxygen radical scavenger may be a therapeutic tool to counteract ANG II dependent remodeling of renal tubular cells.

Combination treatment of enalapril with nitrendipine in rats with renovascular hypertension.

We have recently shown that treatment with the calcium channel blocker nitrendipine may aggravate albuminuria and glomerular injury in rats with two-kidney, one clip renovascular hypertension if arterial blood pressure is not reduced. To test whether nitrendipine also exerts its adverse renal effects when normotension is achieved, we examined the effect of combined therapy with nitrendipine and the converting enzyme inhibitor enalapril on blood pressure, albuminuria, glomerular filtration rate, and morphology of the nonclipped kidney. Rats treated with enalapril alone or in combination with the diuretic hydrochlorothiazide or rats treated with nitrendipine alone served as controls. Therapy was started 6 weeks after clipping of one renal artery. Nitrendipine alone did not reduce blood pressure but significantly increased albuminuria, diuresis, glomerular filtration rate, and glomerular volume and injury compared with untreated hypertensive controls. Increase of glomerular filtration rate, diuresis, and albuminuria was reversible after withdrawal of nitrendipine. Treatment with enalapril alone decreased blood pressure significantly but not to normotensive levels and was without significant effect on albuminuria and glomerular morphology. The combination of nitrendipine and enalapril reduced blood pressure to normotensive levels and not only prevented the increase of glomerular volume, glomerular filtration rate, diuresis, and albuminuria caused by nitrendipine alone but furthermore improved glomerular injury and albuminuria to levels not significantly different from normotensive controls. Enalapril in combination with the diuretic had similar beneficial effects on blood pressure, albuminuria, and glomerular injury. These data demonstrate that the adverse effects of nitrendipine monotherapy on glomerular structure and function can be prevented by the combination of nitrendipine and enalapril when blood pressure is normalized.

Adverse effect of the calcium channel blocker nitrendipine on nephrosclerosis in rats with renovascular hypertension.

The effect of a 6-week treatment with the calcium channel blocker nitrendipine or the angiotensin converting enzyme inhibitor enalapril on blood pressure, albuminuria, renal hemodynamics, and morphology of the nonclipped kidney was studied in rats with two-kidney, one clip renovascular hypertension. Six weeks after clipping of one renal artery, hypertensive rats (178 +/- 4 mm Hg) were randomly assigned to three groups: untreated hypertensive controls (n = 8), enalapril-treated (n = 8), or nitrendipine-treated (n = 10). Sham-operated rats served as normotensive controls (128 +/- 3 mm Hg, n = 8). After 6 weeks of treatment, renal hemodynamics (glomerular filtration rate and renal plasma flow) were measured in the anesthetized rats. Renal tissue was obtained for determination of glomerular size and sclerosis. Enalapril but not nitrendipine reduced blood pressure significantly. After 6 weeks of therapy, glomerular filtration rate was not different among the studied groups. Renal plasma flow increased, but albumin excretion and glomerulosclerosis did not change after enalapril treatment. In contrast, in the nitrendipine-treated group albuminuria increased from 12.8 +/- 2 progressively to 163 +/- 55 compared with 19.2 +/- 9 mg/24 hr in the hypertensive controls. Furthermore, glomerulosclerosis index was significantly increased in the nitrendipine-treated group compared with the hypertensive controls (0.38 +/- 0.1 versus 0.13 +/- 0.04). In addition, glomerular size was higher in the nitrendipine-treated group (14.9 +/- 0.17 10(-3) mm2) but lower in the enalapril-treated group (11.5 +/- 0.15 10(-3) mm2) compared with the hypertensive controls (12.1 +/- 0.17 10(-3) mm2).(ABSTRACT TRUNCATED AT 250 WORDS)

PKC alpha regulates thrombin-induced PDGF-B chain gene expression in mesangial cells.

Thrombin is a potent mitogen for mesangial cells and stimulates PDGF B-chain gene expression in these cells. It also activates phospholipase C (PLC) resulting in an increase in cytosolic Ca2+ and diacylglycerol (DAG) that are the physiological activators of protein kinase C (PKC). Immunoprecipitation of specific PKC isotypes from thrombin-stimulated mesangial cells with subsequent measurement of their enzymatic activity shows activation of Ca(2+)-dependent PKC alpha and Ca(2+)-independent PKC zeta in a time dependent manner. Optimum activation of both of these isozymes was obtained at 60 minutes. PKC alpha activity increased 83% over basal while activity of PKC zeta increased 104%. Prolonged exposure of mesangial cells to phorbol myristate acetic acid (PMA) inhibited the enzymatic activity of PKC alpha but not PKC zeta. This inhibition of PKC alpha had no effect on thrombin-induced DNA synthesis but abolished PDGF B-chain gene expression induced by thrombin. These data provide the first evidence that PKC alpha activation is necessary for thrombin-induced PDGF B-chain gene expression but not for thrombin-induced DNA synthesis.