Characterization of titanium dioxide and zinc oxide nanoparticles in sunscreen powder by comparing different measurement methods.

Numerous consumer products, such as cosmetics, contain nanoparticles (NPs) of titanium dioxide (TiO2) or zinc oxide (ZnO); however, this raises questions concerning the safety of such additives. Most of these products do not indicate whether the product includes NPs. In this study, we characterized metal oxide NPs according to size, shape, and composition as well as their aggregation/agglomeration characteristics. In order to comprehend quickly the characterization of metal oxide NPs, we employed single particle inductively coupled plasma (SP-ICPMS) to help quantify the size of metal oxide NPs; then, we use transmission electron microscopy (TEM) to corroborate the results. The crystal size and structure was measured by X-ray diffraction (XRD), there are two crystal phase of TiO2 NPs in sunscreen powder showed in XRD. However, SP-ICPMS proved highly effective in determining the size of NPs, the results of which remarkably good agreement with the TEM measurements. Pre-treatment included a conventional copper grid (requiring sample dilution) to evaluate the size, shape and composition of primary particles or plastic embedding (without the need for sample dilution) to evaluate the aggregate/aggregation of native NOAAs. The proposed method is an effective and fast approach to the characterization of oxide NPs in cosmetic sunscreen powder. These findings outline an alternative approach to the analysis of NPs in powder-form matrix.

[Impact of maternal risky behaviors on the behaviors of children born to adolescent and young mothers].

Objective: To examine the impact of maternal risky behaviors on the behaviors of children born to adolescent and young mothers. Methods: Adolescents and young Chinese mothers were recruited from an integrated young mother supportive program in Hong Kong between January and June 2015. Eligible mothers were asked to complete a questionnaire on their sociodemographic characteristics and history of risky behavior as well as their children's behaviors. Multiple regression analyses were conducted to explore the association between maternal risky behaviors and their children's behaviors. Results: Among 201 respondents, there were 187 (93.0%) ex-drinkers, 136 (67.7%) ex-smokers, and 83 (41.3%) ex-addicts. Compared to the reference group, children of mothers with drug use behaviors were more likely to have abnormal SDQ total difficulties scores (odds ratio 2.60, P=0.01), those of ex-drinking mothers had more behavioral difficulties and more conduct problems (B=3.82 and 1.37, P both=0.01) and those of ex-smoking mothers had more conduct problems (B=0.74, P=0.01) after adjustment for confounders. Children of active drug-taking mothers also had more emotional symptoms (B=1.77, P=0.04) and hyperactivity/inattention problems (B=2.14, P=0.03). Conclusion: The history of mother's risky behavior was significantly associated with the behavioral problems of the children.

LncRNA colon cancer-associated transcript 1 (CCAT1) promotes proliferation and metastasis of ovarian cancer via miR-1290.

OBJECTIVE: Ovarian cancer is one of the leading causes of cancer-related death in women, but treatment remained unsatisfactory. Studies have shown that lncRNA colon cancer-associated transcript 1 (CCAT1) plays an important regulatory role in different cancers, but its role in ovarian cancer remained largely unclear. PATIENTS AND METHODS: Quantitative Real-time polymerase chain reaction (qRT-PCR) was applied to detect the expression of lncRNA CCAT1 in ovarian cancer and adjacent tissue, and analysis was applied to explore the relationship between expression and clinical characteristic. After lncRNA CCAT1 suppression, Cell Counting Kit-8 (CCK8) and wound-healing assay were used to detect the proliferation and metastasis ability of ovarian cancer, respectively. RESULTS: qRT-PCR showed that lncRNA CCAT1 was highly expressed in ovarian cancer tissue, compared with adjacent tissue. Moreover, we found that the expression of lncRNA CCAT1 was closely related to prognosis, tumor size, and lymph node metastasis. We also found that lncRNA CCAT1 could sponge miR-1290 in ovarian cancer. CONCLUSIONS: In this study, we found that lncRNA CCAT1 could sponge miR-1290 in ovarian cancer, and was closely related to prognosis, proliferation, and metastasis.

Characterizing titanium dioxide and zinc oxide nanoparticles in sunscreen spray.

OBJECTIVE: Numerous commercial products contain titanium dioxide (TiO2 ) and zinc oxide (ZnO) nanoparticles (NPs); however, many of these are not labelled as containing NPs. This study sought to develop an effective means of characterizing TiO2 and ZnO NPs in sunscreen sprays, including the size, shape and composition of the particles as well as their aggregation/agglomeration characteristics. METHODS: Transmission electron microscopy (TEM) coupled with a window-type microchip K-kit/copper grid and X-ray diffraction (XRD) was used to characterize the oxide NPs. RESULTS: TME pre-treatment was performed using two approaches: using a conventional copper grid (requiring dilution) and using a K-kit (not requiring dilution). The use of K-kit in conjunction with XRD makes it possible to obtain direct measurements from samples that have not undergone pre-treatment, which could otherwise alter the nature of the samples, such as the degree of agglomeration. XRD was used to obtain information related to particle size and crystal structure. A strong correlation was observed between XRD and TEM measurements. CONCLUSION: The proposed measurement methods were shown to be highly effective in the characterization of oxide NPs in sunscreen sprays, providing consistent information related to NPs and their interactions in the formulations.

Renal effects of non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors.

Nonsteroidal antiinflammatory drugs (NSAID) are one of the most commonly used medications worldwide to inhibiting COX activity for the treatment of pain and inflammation. Their nephrotoxicity has been well documented. With the development and clinical implementation of new COX-2 inhibitors, the safety, including the effects on renal function and blood pressure, is attracting increasing attention. In the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in mediation of renin release, regulation of sodium excretion and maintenance of renal blood flow. Similar to conventional NSAIDs, inhibition of COX-2 may cause edema and modest elevations in blood pressure in a minority of subjects. COX-2 inhibitors may also exacerbate preexisting hypertension or interfere with other antihypertensive drugs. Occasional acute renal failure has also been reported. Caution should be taken when COX-2 inhibitors are prescribed, especially in high-risk patients (including elderly and patients with volume depletion). Recently, agents with combined lipooxygenase/COX inhibition and agents that combine NSAIDs with a nitric oxide (NO) donor have been reported to reduce adverse renal effects.

Cyclooxygenase-2 and the renal renin-angiotensin system.

In the kidney, cyclooxygenase-2 (COX-2) is expressed in the macula densa/cTALH and medullary interstitial cells. The macula densa is involved in regulating afferent arteriolar tone and renin release by sensing alterations in luminal chloride via changes in the rate of Na(+)/K(+)/2Cl(-) cotransport, and administration of non-specific cyclooxygenase inhibitors will blunt increases in renin release mediated by macula densa sensing of decreases in luminal NaCl. High renin states [salt deficiency, angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers, diuretic administration or experimental renovascular hypertension] are associated with increased macula densa/cTALH COX-2 expression. Furthermore, there is evidence that angiotensin II and/or aldosterone may inhibit COX-2 expression. In AT1 receptor knockout mice, COX-2 expression is increased similar to increases with ACE inhibitors or AT1 receptor blockers. Direct administration of angiotensin II inhibits macula densa COX-2 expression. Previous studies demonstrated that alterations in intraluminal chloride concentration are the signal for macula densa regulation of tubuloglomerular feedback and renin secretion, with high chloride stimulating tubuloglomerular feedback and low chloride stimulating renin release. When cultured cTALH or macula densa cells were incubated in media with selective substitution of chloride ions, COX-2 expression and prostaglandin production were significantly increased. A variety of studies have indicated a role for COX-2 in the macula densa mediation of renin release. In isolated perfused glomerular preparations, renin release induced by macula densa perfusion with a low chloride solution was inhibited by a COX-2 inhibitor but not a COX-1 inhibitor. In vivo studies in rats indicated that increased renin release in response to low-salt diet, ACE inhibitor, loop diuretics or aortic coarctation could be inhibited by administration of COX-2-selective inhibitors. In mice with genetic deletion of COX-2, ACE inhibitors or low-salt diet failed to increase renal renin expression, although renin significantly increased in wild type mice. In contrast, in COX-1 null mice there were no significant differences in either the basal or ACE inhibitor-stimulated level of renal renin activity from plasma or renal tissue compared with wild type mice. In summary, there is increasing evidence that COX-2 expression in the macula densa and surrounding cortical thick ascending limb cells is regulated by angiotensin II and is a modulator of renal renin production. These interactions of COX-2 derived prostaglandins and the renin-angiotensin system may underlie physiological and pathophysiological regulation of renal function.

Downregulation of phospholipase C delta3 by cAMP and calcium.

Four different isoforms of mammalian phospholipase C delta (PLCdelta) have been described. PLCdelta1, the best-understood isoform, is activated by an atypical GTP-binding protein. It has been suggested that it is a calcium signal amplifier. However, very less is known about other subtypes, including PLCdelta3. Therefore, in the present study, we examined the expression of PLCdelta3 in different human tissues. Moreover, the cellular underlying regulation for PLCdelta3 was studied in different cell lines. Our study showed that the mRNA and protein levels differed significantly among human tissues. The human PLCdelta3 gene was composed of 15 exons and 1 putative cAMP response element in the 5'-end promoter region. PLCdelta3 mRNA expression was downregulated by cAMP and calcium in both the human normal embryonic lung tissue diploid WI38 cell line and the glioblastoma/astrocytoma U373 cell line. However, mRNA expression showed no impact by PKC activators or inhibitors. This study shows the human PLCdelta3 expression pattern and is the first report that PLCdelta3 gene expression is downregulation by cAMP and calcium.

X-ray absorption studies of carbon-related materials.

X-ray absorption near-edge structure (XANES) measurements have been performed on nitrogen-doped diamond films with three different dopant concentrations and iron-layer-stabilized carbon nanotube (CNT) structures with various diameters at the C K-absorption edge using the sample drain current mode. The C K-edge XANES spectra of these N-doped diamond films resemble that of the undoped diamond regardless of the dopant concentration, which suggest that the overall bonding configuration of the C atom is unaltered. N dopants are found to reduce the intensities of both the sp2- and sp3-bond-derived resonance features in the XANES spectra. On the other hand, the C K-edge XANES spectra of CNTs indicate that the intensities of the pi* and sigma* bands and the interlayer-state features vary with the diameter of the CNT. This phenomenon may be caused by the Fe-layer-catalysed bending of the graphite sheet and the interaction between C and Fe atoms.

Relationship between six-minute walking test and pulmonary function and ventilatory drive in patients with airflow limitation.

BACKGROUND: We studied the correlation between exercise tolerance and pulmonary function, arterial blood gases, and ventilatory drive in patients with airflow limitation (AFL). METHODS: Forty-one patients (36 men, 5 women, mean age 63.6 +/- 10.3 years) with forced expiratory volume in one second (FEV1) < 75% and FEV1/forced vital capacity (FVC) < 75% were enrolled. All patients were clinically stable with no impairment of the lower extremities. On the first day of the study, pulmonary function test (PF), including FVC, FEV1, diffusion capacity (DLCO), and residual volume (RV)/total lung capacity (TLC) was measured by plethysmography. On the next day, ventilatory drive P0.1 were measured before drawing blood gases. Then, a 6-minute walking test with pulse-oxymetry and end tidal CO2 monitoring was performed. Ventilation efficiency (O2SATp & ETCO2) was recorded every 6 seconds during exercise. RESULTS: The walking distance (WD) was significantly correlated to PF: FVC%, FEV1%, DLCO%, and RV/TLC. There was also a significant correlation between resting arterial blood gases (PaO2, PaCO2, SatO2) and PF (FVC%, FEV1%, DLCO% and RV/TLC). The SatO2 at the end of exercise was highly correlated to PF (FVC%, FEV1%, DLCO% and RV/TLC). Gas exchange parameters: PaO2, PaCO2, O2SATa, O2SATp at rest, and O2SATp at the end of exercise were also significantly related to WD. CONCLUSION: The magnitude of exercise intolerance in patients with AFL was not only significantly correlated to the impairment of pulmonary function, but also closely related to gas exchange during exercise. Therefore, limitation of ventilation could be identified earlier using an exercise test.

Genetic deletion of COX-2 prevents increased renin expression in response to ACE inhibition.

Cyclooxygenase-2 (COX-2) is expressed in macula densa (MD) and surrounding cortical thick ascending limb of the loop of Henle (cTALH) and is involved in regulation of renin production. We and others have previously found that selective COX-2 inhibitors can inhibit renal renin production (Cheng HF, Wang JL, Zhang MZ, Miyazaki Y, Ichikawa I, McKanna JA, and Harris RC. J Clin Invest 103: 953-961, 1999; Harding P, Sigmon DH, Alfie ME, Huang PL, Fishman MC, Beierwaltes WH, and Carretero OA. Hypertension 29: 297-302, 1997; Traynor TR, Smart A, Briggs JP, and Schnermann J. Am J Physiol Renal Physiol 277: F706-F710, 1999; Wang JL, Cheng HF, and Harris RC. Hypertension 34: 96-101, 1999). In the present studies, we utilized mice with genetic deletions of the COX-2 gene in order to investigate further the potential role of COX-2 in mediation of the renin-angiotensin system (RAS). Age-matched wild-type (+/+), heterozygotes (+/-), and homozygous null mice (-/-) were administered the angiotensin-converting enzyme inhibitor (ACEI), captopril, for 7 days. ACEI failed to significantly increase plasma renin activity, renal renin mRNA expression, and renal renin activity in (-/-) mice. ACEI increased the number of cells expressing immunoreactive renin in the (+/+) mice both by inducing more juxtaglomerular cells to express immunoreactive renin and by recruiting additional renin-expressing cells in the more proximal afferent arteriole. In contrast, there was minimal recruitment of renin-expressing cells in the more proximal afferent arteriole of the -/- mice. In summary, these results indicate that ACEI-mediated increases in renal renin production were defective in COX-2 knockout (K/O) mice and provide further indication that MD COX-2 is an important mediator of the renin-angiotensin system.

Hazardous organic matters in municipal sewage sludge in Taiwan.

Application of municipal sewage sludge to agricultural land has attracted significant attention in recent years because it conserves abundant nutrients and hydrocarbons that can be used as a soil amendment. The presence of hazardous organic matters (HOMs) in sewage sludge limits the feasibility of reuse of sewage sludge. The purpose of this study was to investigate the types and the concentrations of HOMs in municipal sewage sludge in Taiwan. An efficient SFE/GC/MS method was used to determine HOMs in sludge samples. The results indicated that di-(2-ethylhexyl) phthalate (DEHP) was persistently found in both aerobically and anaerobically digested sludges. 4-nonylphenol (4-NP) was only found in anaerobically digested sludges. Both DEHP and 4-NP have been characterized as endocrine disrupting chemicals (EDCs) or environmental endorine disruptors (EEDs). It suggested that sludges containing high levels of DEHP and 4-NP need further treatment and reduction of possible impacts on the environment before their reuse as soil fertilizers.

Role of p38 in the regulation of renal cortical cyclooxygenase-2 expression by extracellular chloride.

We have previously shown that in renal cortex, COX-2 expression is localized to macula densa and surrounding cortical thick ascending limb of Henle (cTALH). Dietary salt restriction increases local expression of COX-2, which mediates renin production and secretion. Given that decreased luminal chloride [Cl(-)] at the level of the macula densa increases renin production and secretion, we investigated the role of extracellular ion concentration on COX-2 expression. Quiescent rabbit cTALH cells were incubated in a physiological salt solution containing high or low levels of NaCl. Immunoreactive COX-2 expression increased significantly in the low NaCl solution. COX-2 expression also increased after administration of the Na(+)/K(+)/2Cl(-) cotransport inhibitor, bumetanide. Selective substitution of chloride led to increased COX-2 expression, whereas selective substitution of sodium had no effect. The p38 MAP kinase inhibitor PD169316 decreased low NaCl-induced COX-2 expression. Low-salt or low-chloride medium induced cultured cTALH to accumulate >/= 3-fold higher levels of pp38, the activated (phosphorylated) form of p38; low-salt medium also increased pJNK and pERK levels. Feeding rats a low-salt diet for 14 days induced a significant increase in renal cortical pp38 expression, predominantly in the macula densa and cTALH. These results suggest that reduced extracellular chloride leads to increased COX-2 expression, which may be mediated by activation of a p38-dependent signaling pathway.

Nitric oxide regulates renal cortical cyclooxygenase-2 expression.

We have previously shown that cyclooxygenase-2 (COX-2) is localized to the cortical thick ascending limb of the loop of Henle (cTALH)/macula densa of the rat kidney, and expression increases in response to low-salt diet and/or angiotensin-converting enzyme (ACE) inhibition. Because of the localization of neuronal nitric oxide synthase (nNOS) to macula densa and surrounding cTALH, the present study investigated the role of nitric oxide (NO) in the regulation of COX-2 expression. For in vivo studies, rats were fed a normal diet, low-salt diet or low-salt diet combined with the ACE inhibitor captopril. In each group, one-half of them were treated with the nNOS inhibitors 7-nitroinidazole (7-NI) or S-methyl-thiocitrulline. Both of these NOS inhibitors inhibited increases in COX-2 mRNA and immunoreactive protein in response to low salt and low salt+captopril. For in vitro studies, COX-2 expression was studied in primary cultures of rabbit cTALH cells immunodisssected with Tamm-Horsfall antibody. Basal COX-2 immunoreactivity expression was stimulated by S-nitroso-N-acetyl-penicillamine (SNAP), an NO donor, and intracellular cGMP concentration. The cultured cells expressed immunoreactive nNOS, and 7-NI inhibited basal COX-2 immunoreactivity expression, which could be partially overcome by cGMP. In summary, these studies indicate that NO is a mediator of increased renal cortical COX-2 expression seen in volume depletion and suggest important interactions between the NO and COX-2 systems in the regulation of arteriolar tone and the renin-angiotensin system by the macula densa.

The effect of incentive spirometry on chest expansion and breathing work in patients with chronic obstructive airway diseases: comparison of two methods.

BACKGROUND: Chronic obstructive airway diseases (COAD), characterized by mucus hypersecretion, lead to exercise intolerance. Incentive spirometry has been used to prevent postoperative pulmonary atelectasis. METHODS: To compare the efficacy of two incentive spirometers, Coach (volume-oriented) and Triflo (flow-oriented), in the work of breathing in COAD patients, 22 patients were randomized in this study: 12 patients (Triflo-II group) initially used Triflo-II for 10 minutes and then Coach for the same period. In contrast, the Coach group, including 10 patients, started with Coach followed by Triflo-II. After receiving incentive spirometry, lung expansion and work of breathing were assessed. RESULTS: Patients in the Coach group significantly increased chest wall expansion (p = 0.041), as compared with patients using Triflo-II. Similarly, there was also a significantly increased abdominal wall expansion in the Coach group (p = 0.0056), compared with that in the Triflo-II group. The need of accessory muscle assistance for breathing in the Coach group was significantly less than in the Triflo-II group (p = 0.047). It was easier for patients in the Coach group to start a breath (p = 0.0058) than for those in the Triflo-II group. For the entire group, 17 patients (77.3%) preferred Coach to assist their breathing, and only 4 patients (18.2%) favored Triflo-II. CONCLUSION: COAD patients achieved a larger expansion of the chest and abdomen with a Coach device. Our data provide a good rationale for an outcome study on the use of incentive spirometer in COAD patients.

A selective cyclooxygenase-2 inhibitor decreases proteinuria and retards progressive renal injury in rats.

BACKGROUND: We have previously shown that cyclooxygenase-2 (COX-2) expression is low in the renal cortex of adult rats, but is increased in macula densa/cortical thick ascending limb and in glomerular podocytes after subtotal renal ablation. METHODS: To evaluate the functional consequences of this increased COX-2 expression, male rats were subjected to subtotal renal ablation and divided into four groups: (1) treatment with the selective COX-2 inhibitor SC58236, (2) treatment with vehicle, (3) treatment with the angiotensin-converting enzyme inhibitor enalapril, and (4) treatment with enalapril + SC58236. The administration of drugs was begun on the third day after ablation and continued for 6 to 10 weeks. RESULTS: Within one week after ablation, vehicle-treated rats developed hypertension. Although enalapril led to significant reductions in blood pressure, either alone or in combination with the COX-2 inhibitor, SC58236 alone did not significantly alter ablation-induced hypertension. However, the SC58236-treated animals exhibited levels of proteinuria at six weeks after ablation that were comparable to those seen with enalapril (vehicle, 47 +/- 4; enalapril, 27 +/- 2; SC58236, 30 +/- 2 mg/day; N = 7, P < 0.01, each group compared with vehicle), and continued SC58236 treatment led to persistent reductions in proteinuria at 10 weeks after renal ablation (vehicle, 77 +/- 4; SC58236, 50 +/- 4 mg/day; N = 6, P < 0. 01). SC58236 treatment also significantly reduced the percentage of glomeruli exhibiting segmental or global sclerosis at 10 weeks (32.6 +/- 7.8% vs. 10.9 +/- 2.8%, N = 6, P < 0.03). Furthermore, SC58236 treatment partially inhibited increases in transforming growth factor-beta1 mRNA expression and increases in collagen III and collagen IV mRNA expression. CONCLUSIONS: These studies indicate that chronic treatment with a specific COX-2 inhibitor may retard the progression of progressive renal injury, and suggest that such compounds can be used in combination with angiotensin-converting enzyme inhibitors. Further studies are required to determine the mechanism by which COX-2 inhibition is renoprotective.

Cyclooxygenase-2-selective inhibitors impair glomerulogenesis and renal cortical development.

BACKGROUND: Antenatal exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) has been associated with renal dysgenesis in humans. METHODS: These studies characterized cyclooxygenase-2 (COX-2) versus COX-1-selective inhibition on nephrogenesis in the rodent using histomorphometry, immunohistology, and in situ hybridization. RESULTS: Administration of a COX-2-selective inhibitor (SC58236), started during pregnancy until weaning, significantly impaired development of the renal cortex and reduced glomerular diameter in both mice and rats. An identical phenotype was demonstrated in COX-2 -/- mice. In contrast to its effects on the developing kidney, a COX-2 inhibitor had no effect on glomerular volume in adult mice. This effect was specific for COX-2 because maternal administration of a COX-1-selective inhibitor (SC58560) did not affect renal development despite significantly inhibiting gastric mucosal prostaglandin E2 (PGE2) synthesis in pups. The expression of COX-2 immunoreactivity peaked in the first postnatal week and was localized to S-shaped bodies and the macula densa in the cortex. Treatment with a COX-2 inhibitor during this period (from postnatal day 0 to day 21) severely reduced glomerular diameter, whereas treatment limited to pregnancy did not affect glomerular size. CONCLUSION: These data demonstrate an important role for COX-2 activity in nephrogenesis in the rodent, and define a specific time period of susceptibility to these effects.

Cyclooxygenase-2 inhibition decreases renin content and lowers blood pressure in a model of renovascular hypertension.

It has been proposed that the macula densa participates in the regulation of increased renin expression in renovascular hypertension (RVH) and that prostaglandins may be among the mediators of macula densa function. We have previously shown that in renal cortex, cyclooxygenase-2 (COX-2) expression is localized to the macula densa and surrounding cortical thick ascending limb and increases in high-renin states, such as salt restriction and angiotensin-converting enzyme inhibition. In the present studies, we examined the effect of the selective COX-2 inhibitor SC58236 on plasma renin activity (PRA) and renal renin expression in RVH in rats. The aorta was coarcted between right and left renal arteries, and animals received either SC58236 or vehicle for 1 week. At day 8, vehicle-treated coarcted rats were hypertensive (mean carotid arterial blood pressure: 138+/-3 versus 87+/-2 mm Hg in sham-operated controls; n=9 to 11; P<0.001) and exhibited a disparity of kidney size (ratio left/right kidney: 0.78+/-0.04 versus 1.02+/-0.02; n=9 to 10; P<0.001). PRA increased significantly (84.6+/-6.5 versus 9.0+/-1.4 ng angiotensin I [Ang I] per milliliter per hour; n=8 to 9; P<0.01). In the coarcted rats, neither renin mRNA expression nor renin activity of the right kidney was altered (renin/GAPDH mRNA: 1.12+/-0.05-fold levels in control rats; n=6; P=NS; renin activity: 23.4+/-1.8 versus 27.1+/-3.4 ng Ang I per hour per milligram protein; n=8 to 9; P=NS). However, the renin mRNA of the left kidney increased to 3.0+/-0.6-fold of control (n=6), and the renin activity increased to 189.0+/-28.6 ng Ang I per hour per milligram protein (n=8; P<0.01). Expression of COX-2 mRNA and immunoreactive protein increased in the affected left kidney but was not different from control in the unaffected right kidney. SC58236 treatment to coarcted rats did not affect kidney size (ratio left/right kidney: 0.79+/-0.06; n=9). However, PRA was significantly decreased compared with the vehicle-treated coarcted rats (19.8+/-2. 8 ng Ang I per milliliter per hour; n=9; P<0.01). The left kidney renin mRNA and renin content were also decreased (1.7+/-0.3-fold control; n=6; P<0.05; and 45.7+/-7.6 ng Ang I per hour per milligram protein; n=9; P<0.01, respectively), while renin mRNA and renin content of the right kidney were not altered. SC58236 lowered mean arterial blood pressure (122+/-5 mm Hg; n=14; P<0.05 compared with vehicle). A significant correlation was observed between PRA and mean blood pressure (r=0.75; P<0.01). In summary, these studies indicate that the selective COX-2 inhibitor SC58236 decreases renin production and release in RVH and suggest an important role for COX-2 regulation of the renin-angiotensin system.

Activation of phospholipase C delta1 through C2 domain by a Ca(2+)-enzyme-phosphatidylserine ternary complex.

The concentration of free Ca(2+) and the composition of nonsubstrate phospholipids profoundly affect the activity of phospholipase C delta1 (PLCdelta1). The rate of PLCdelta1 hydrolysis of phosphatidylinositol 4,5-bisphosphate was stimulated 20-fold by phosphatidylserine (PS), 4-fold by phosphatidic acid (PA), and not at all by phosphatidylethanolamine or phosphatidylcholine (PC). PS reduced the Ca(2+) concentration required for half-maximal activation of PLCdelta1 from 5.4 to 0.5 microM. In the presence of Ca(2+), PLCdelta1 specifically bound to PS/PC but not to PA/PC vesicles in a dose-dependent and saturable manner. Ca(2+) also bound to PLCdelta1 and required the presence of PS/PC vesicles but not PA/PC vesicles. The free Ca(2+) concentration required for half-maximal Ca(2+) binding was estimated to be 8 microM. Surface dilution kinetic analysis revealed that the K(m) was reduced 20-fold by the presence of 25 mol % PS, whereas V(max) and K(d) were unaffected. Deletion of amino acid residues 646-654 from the C2 domain of PLCdelta1 impaired Ca(2+) binding and reduced its stimulation and binding by PS. Taken together, the results suggest that the formation of an enzyme-Ca(2+)-PS ternary complex through the C2 domain increases the affinity for substrate and consequently leads to enzyme activation.