Prostaglandin E1-induced vasorelaxation in porcine coronary arteries.

The mechanism of prostaglandin E1 (PGE1)-induced vasorelaxation was studied in the porcine left anterior descending artery (diameter = 2.0-3.0 mm) and its branches (diameter = 0.6-1.0 mm). In the large coronary arteries, PGE1 increased the basal tone at concentrations from 10(-8) to 3 x 10(-7) M and decreased the tone at concentrations above 3 x 10(-7) M. However, in the small coronary arteries, PGE1 did not affect the basal tone at concentrations below 3 x 10(-6) M and evoked only relaxation at above 10(-5) M. PGE1 caused dose-dependent relaxation of vessels previously contracted by prostaglandin F2 alpha or endothelin-1 at concentrations above 10(-7) M in large coronary arteries and above 10(-8) M in small coronary arteries. Removal of the endothelium did not influence the relaxant response to PGE1 of either type of artery. In addition, 10(-4) M aspirin did not influence the PGE1-induced vasorelaxation of large and small coronary arteries. However, treatment with 5 x 10(-6) M ouabain or partial replacement of Na+ with Li+ (Na+ concentration, 25 mEq/l) significantly attenuated the relaxant response to PGE1 in large and small coronary arteries. These results indicate that the responsiveness of large and small coronary arteries to PGE1 differs in the pig and that the electrogenic Na+ pump has a primary role in the relaxant effect of PGE1 on both small and large arteries.     

In vitro pharmacodynamic effects of concentration, pH, and growth phase on serum bactericidal activities of daptomycin and vancomycin.

Clinical trials with daptomycin were halted in December 1990 because of treatment failures including two resistant Staphylococcus aureus strains. High protein binding of daptomycin (> 90%) and the lower-than-expected concentrations in serum with the dosage regimen of 3 mg/kg of body weight every 12 h may have contributed to these failures. To evaluate the effect that higher concentrations would have on bactericidal activity measured by time-kill curves, peak and trough concentrations were estimated for dosage regimens of 3, 5, and 10 mg/kg every 12 h. MICs, MBCs, and killing curves for daptomycin and vancomycin were performed by using the estimated concentrations with four S. aureus strains obtained from patients who failed daptomycin therapy for endocarditis. MICs and MBCs of daptomycin demonstrated a greater inoculum effect than those of vancomycin; MICs and MBCs of daptomycin increased three- to fourfold, but those of vancomycin increased only one- to twofold when the inoculum was increased from 5 x 10(5) to 5 x 10(7) CFU/ml. No pH-dependent effect on MICs or MBCs was seen. Strenuous experimental conditions were chosen: high inoculums (5 x 10(7) CFU/ml), extremes of pH (6.4, 7.4, and 8), and stationary and exponentially growing organisms; and all experiments completed in the presence of pooled human serum. Daptomycin exhibited concentration-dependent killing and statistically faster kill rates than vancomycin against stationary- or exponential-growth-phase organisms. A pH-dependent decrease in activity with daptomycin was also demonstrated. Daptomycin and vancomycin produced higher kill rates against exponentially growing organisms. A pH-dependent decrease in activity with daptomycin was also demonstrated. Daptomycin and vancomycin produced higher kill rates against exponentially growing organisms. The results indicate that the use of higher dosage regimens with compounds similar to daptomycin may be capable of overcoming the effects of pH, high inoculum, and protein binding.     

Effect of Maalox on the bioavailability of oral gemifloxacin in healthy volunteers

This open, randomized, 4-way crossover study investigated the effect of the antacid Maalox on the bioavailability of gemifloxacin, a novel fluoroquinolone antimicrobial. Sixteen healthy male volunteers received gemifloxacin, 320 mg p.o., alone, 3 h after Maalox administration, or 10 min or 2 h before Maalox administration. Blood was sampled for 48 h after dosing to determine pharmacokinetic parameters. Estimates for the differences between regimens and 95% confidence intervals were calculated using the t-test for paired data. The administration of gemifloxacin 10 min before Maalox resulted in an average 85% reduction in the area under the plasma concentration-time curve from time zero extrapolated to infinity (AUC(0-infinity)), whereas administration 3 h after Maalox produced a decrease in AUC(0-infinity), 15% of which was not considered to be clinically significant. The administration of gemifloxacin 2 h before Maalox had no notable effect on the gemifloxacin AUC(0-infinity) (average increase of 3%). Similar results were seen for the maximum gemifloxacin plasma concentration (C(max)). Neither the time to C(max) nor the half-life of gemifloxacin were notably altered by the administration of Maalox at any time relative to gemifloxacin dosing. There were no clinically important adverse experiences or changes in clinical laboratory parameters during this study. The findings of this study support the dosing recommendation that gemifloxacin can be administered either 2 h or more prior to, or 3 h or more after, the administration of Maalox. Copyright Copyright 1999 S. Karger AG, Basel.     

Successful weaning from cardiopulmonary bypass with central venous prostaglandin E1 and left atrial norepinephrine infusion in patients with acute pulmonary hypertension.

OBJECTIVE: Postoperative pulmonary hypertension increases the mortality risk in cardiac surgery. We have used central venous prostaglandin E1 (PGE1) and left atrial norepinephrine (NE) infusion to wean from cardiopulmonary bypass (CPB) patients with refractory postoperative pulmonary hypertension. DESIGN: Observational, nonrandomized study. SETTING: Department of Cardiac Surgery in a university hospital. PATIENTS: We studied 10 nonconsecutive American Society of Anesthesiologists III and New York Heart Association class III-IV patients with postoperative pulmonary hypertension and low cardiac output syndrome preventing separation from CPB. INTERVENTIONS: Patients received right atrial PGE1 (31.5 +/- 6.26 ng/kg/min) and left atrial NE (0.11 +/- 0.02 microg/kg/min) infusion. Hemodynamic data were obtained before CPB (T0), after CPB under maximal inotropes and vasodilator infusion (T1), 10 mins (T2) and 12 hrs (T3) after PGE1 and NE infusion, and 48 hrs after withdrawal of PGE1 and NE (T4). MEASUREMENTS AND MAIN RESULTS: All patients were successfully weaned from CPB and survived. The biatrial infusion of PGE1 and NE caused a dramatic reduction in mean pulmonary artery pressure (from 42.8 +/- 5.1 mm Hg at T1 to 28.5 +/- 2.6 mm Hg at T2 and 20.5 +/- 2.0 mm Hg at T4), pulmonary vascular resistance index (from 1158 +/- 269 dyne x sec/cm5 x m2 at T1 to 501 +/- 99 dyne x sec/cm5 x m2 at T2 and 246 +/- 50 dyne x sec/cm5 x m2 at T4), and pulmonary-to-systemic vascular resistance index ratio (from 0.61 +/- 0.17 at T1 to 0.20 +/- 0.04 at T2 and 0.11 +/- 0.03 at T4). Cardiac index increased from 1.7 +/- 0.2 L/min/m2 at T1 to 2.3 +/- 0.2 L/min/m2 at T2 and 2.9 +/- 0.1 L/min/m2 at T4. CONCLUSIONS: In patients with refractory postoperative pulmonary hypertension, the combined administration of low-dose PGE1 in the right atrium and NE in the left atrium is an effective means to wean patients from cardiopulmonary bypass.     

Prostaglandin protects isolated guinea pig chief cells against ethanol injury via an increase in diacylglycerol.

We studied cellular processes activated by prostaglandins (PG) that are involved in the protection of gastric chief cell injury estimated in terms of dye exclusion test, release of lactate dehydrogenase (LDH), or 51Cr from prelabeled chief cells. Pretreatment of chief cells with 3 x 10(-6) M PGE2 or PGE1 at 37 degrees C and pH 7.4 for 15 min maximally reduced not only ethanol- but also taurocholic acid-caused LDH release from chief cells. PGs equipotently stimulated increases in the accumulation of diacylglycerol and cyclic AMP without elevating intracellular Ca2+ concentrations in gastric chief cells. The rank order of the potency was equal to that of PGs to reduce the injury. Pretreatment of chief cells with synthetic 1-oleoyl-2-acetyl-sn-glycerol (OAG) or 12-o-tetradecanoyl phorbol 13-acetate (TPA) reduced the injury of chief cells, while 4 alpha-phorbol 12,13-didecanoate, an inactive phorbol ester, failed to reduce the injury and 1-(5-isouinolinylsulfonyl)-2-methylpiperazine (H7) blocked the protective action of PGE2. On the other hand, forskolin and dbcAMP had no effect on ethanol-caused LDH release and diacylglycerol formation in chief cells. These results suggest that PGE2 and PGE1 possess the direct protective action against ethanol- or taurocholic acid-caused injury in chief cells, presumably through the activation of the diacylglycerol/protein kinase C signaling pathway.     

Linezolid compared with eperezolid, vancomycin, and gentamicin in an in vitro model of antimicrobial lock therapy for Staphylococcus epidermidis central venous catheter-related biofilm infections

Central venous catheter (CVC)-related infection (CVC-RI) is a common complication of CVC use. The most common etiological agents of CVC-RI are gram-positive organisms, in particular, staphylococci. An in vitro model for the formation of biofilms by Staphylococcus epidermidis ATCC 35984 on polyurethane coupons in a modified Robbins device was established. Biofilm formation was confirmed by electron microscopy and was quantified by determination of viable counts. Mueller-Hinton broth was replaced with sterile physiological saline (control) or a solution of vancomycin (10 mg/ml), gentamicin (10 mg/ml), linezolid (2 mg/ml), or eperezolid (4 mg/ml). Viable counts were performed with the coupons after exposure to antimicrobials for periods of 24, 72, 168, and 240 h. The mean viable count per coupon following establishment of the biofilm was 4.6 x 10(8) CFU/coupon, and that after 14 days of exposure to physiological saline was 2.5 x 10(7) CFU/coupon. On exposure to vancomycin (10 mg/ml), the mean counts were 2.5 x 10(7) CFU/coupon at 24 h, 4.3 x 10(6) CFU/coupon at 72 h, 1.4 x 10(5) CFU/coupon at 168 h, and undetectable at 240 h. With gentamicin (10 mg/ml) the mean counts were 2.7 x 10(7) CFU/coupon at 24 h, 3.7 x 10(6) CFU/coupon at 72 h, 8.4 x 10(6) CFU/coupon at 168 h, and 6.5 x 10(6) CFU/coupon at 240 h. With linezolid at 2 mg/ml the mean counts were 7.1 x 10(5) CFU/coupon at 24 h and not detectable at 72, 168, and 240 h. With eperezolid (4 mg/ml) no viable cells were recovered after 168 h. These data suggest that linezolid (2 mg/ml) and eperezolid (4 mg/ml) achieve eradication of S. epidermidis biofilms more rapidly than vancomycin (10 mg/ml) and gentamicin (10 mg/ml).     

Growth of gram-positive and gram-negative bacteria in platelet concentrates

In 1986 the allowable platelet storage time was reduced from 7 to 5 days because of a recent increase in septic deaths associated with platelet transfusion. In this study, the growth curves of two gram-positive and two gram-negative organisms in platelets stored for 7 days in CLX and PL-732 bags were evaluated. Platelets in CLX bags were inoculated with 10(1), 10(2), and 10(3) organisms and 10(2) organisms were introduced into PL-732 bags. Test organisms were inoculated into trypticase soy broth as a control. All four bacteria grew rapidly in trypticase soy broth, reaching 10(9) organisms per mL within 48 hours. In both CLX and PL-732 bags, the growth pattern of gram-positive organisms was generally logarithmic during the first few days of storage. A concentration of 10(8) organisms per mL was present by Day 3 or 4, after which further proliferation was inhibited by the high density of bacteria in the platelets. In PL-732 bags, the proliferation of gram-negative organisms followed a pattern similar to that of the gram-positive bacteria. However, gram-negative organisms grew less well in CLX bags.(ABSTRACT TRUNCATED AT 250 WORDS)     

Potentiation of nociceptive responses to low pH injections in humans by prostaglandin E2.

Inflammation and trauma lead to tissue acidification and release of inflammatory mediators, including prostaglandin E2 (PGE2). Protons can evoke pain through acid-sensing ion channels (ASICs) and TRPV1 receptors. In this study, we examined whether PGE2 can potentiate proton-induced nociception in humans on injection into skin and muscle. Psychophysical and vascular responses to microinjections of protons (pH 6.0 and 6.5), PGE2 (10-6 and 10-7 M) and their combinations into forearm skin (30 microL) or anterior tibial muscle (50 microL) were assessed in 16 male subjects. Pain intensity, axon reflex erythema, and heat pain thresholds were recorded after skin challenge; pain intensity and thresholds for pressure-evoked pain were recorded after intramuscular injections. Intradermal or intramuscular injections of PGE2 induced very low levels of pain similar to saline. Administration of low pH caused moderate pain within 5 seconds that declined rapidly over 15 to 20 seconds. In comparison, coinjection of low pH with PGE2 led to a biphasic profile of the pain response. Combined pH + PGE2 stimulation provoked significantly increased pain in the second phase after injections (20 to 100 seconds) both in skin and muscle, whereas the initial injection pain was not enhanced. Heat pain thresholds were reduced after PGE2 and combined pH + PGE2, whereas flare responses were rather attenuated on coadministration of low pH with PGE2. Intriguingly, when compared with skin, muscle pain was significantly lower in the initial phase (0 to 15 seconds) but significantly higher in the second phase (20 to 100 seconds after injection). PERSPECTIVE: PGE2 can potentiate nociceptor activation by protons in human skin and muscle, indicated by increased sustained pain ratings. This can be best explained by TRPV1 sensitization in the presence of PGE2, a mechanism potentially relevant for inflammatory and injury-induced pain.     

Recovery of S. epidermidis and E. coli from effluent peritoneal dialysate

The effect of incubation temperature and duration was studied on the growth of organisms in peritoneal dialysate effluent. Penicillin-sensitive, and gentamicin-sensitive clinical isolates of S. epidermidis (SE) and E. Coli (EC), respectively, were inoculated into freshly drained dialysate of 19 CAPD patients who did not have peritonitis. Each dialysate was 1.5% dextrose in strength and had a minimum dwell of 6 hours. Control and test aliquots were incubated at 4 degrees C, 20 degrees C and 37 degrees C for periods of up to 12 hours, and samples collected and plated to determine colony counts. Initial counts at time zero were 9.4 x 10(4) (SE) and 6.6 x 10(3) (EC) CFU/ml. SE showed no change in count at 4 or 20 degrees C up to 12 hours. There was a significant increase (p less than 0.005) at 37 degrees C, at 12 hours to 1.72 x 10(6) CFU/ml. EC showed no change at 4 or 20 degrees C. There was a significant decrease in count for EC at 37 degrees C, 6 hours (5.5 x 10(2) CFU/ml, p less than 0.01) and 37 degrees, 12 hours (2.9 x 10(2) CFU/ml, p less than 0.0001). It is recommended that infected dialysate should be stored in cool conditions until it can be transported for culture to ensure adequate recovery of gram negative organisms.     

CD34+ cell dose requirements for rapid engraftment in a sequential high-dose chemotherapy regimen of paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin (CTCb) with PBPC support in metastatic breast cancer

Sequential high-dose chemotherapy may increase the threshold dose of CD34+ cells necessary for rapid and successful hematologic recovery. There are limited data regarding the pharmacodynamics and threshold CD34+ cell dose required for engraftment following high-dose paclitaxel. To determine the dose of CD34+ PBPC sufficient for rapid engraftment, 65 women with metastatic breast cancer undergoing a sequential high-dose paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin (CTCb) chemotherapy regimen were evaluated. The intertreatment interval was a median of 27 days. Paclitaxel was escalated from 400 to 825 mg/m2, infused continuously (CI) over 24 h on day -4 with PBPC reinfusion on day 0. Following marrow recovery, 90 mg/m2/day of melphalan was given over 30 min on days -2 and -1, with PBPC reinfusion on day 0. On recovery, patients received CTCb on days -7 to -3, with PBPC reinfusion on day 0. G-CSF was administered after each cycle until WBCC recovery. For paclitaxel, an ANC >0.5 x 10(9)/L occurred at a median of 6 days (range 0-7 days) after PBPC reinfusion. The median nadir platelet count was 63 x 10(9)/L (range 6 x 10(9)/L-176 x 10(9)/L). Eight patients (12%) had platelet nadir <20 x 10(9)/L, and all recovered their counts to >20 x 10(9)/L on day 7. There was no clinical difference in days to engraftment between women receiving <2 or > or =2 x 10(6) CD34+ PBPC/kg following paclitaxel. All patients recovered neutrophil and platelet counts within 7 days after reinfusion of > or =1 x 10(6) CD34+ cells/kg and G-CSF. The data suggest that a paclitaxel dose of 825 mg/m2 is not myeloablative. For melphalan, median days to ANC >0.5 x 10(9)/L was 10 days (range 9-15), and platelet recovery to >20 x 10(9)/L was 13 days (range 0-28) after PBPC reinfusion. Median time to engraftment was more rapid in patients receiving > or =2 x 10(6) CD34+/kg versus <2 x 10(6)CD34+/kg, for both neutrophils (11 days versus 10 days, p = 0.05) and platelets (14 days versus 12 days, p < 0.01). Ninety-eight percent of patients infused with > or =2 x 10(6) CD34+/kg engrafted within 21 days. Following CTCb in this sequential regimen, a dose of > or =2 x 10(6) CD34+ cells/kg provided for significantly more rapid neutrophil engraftment than <2 x 10(6) CD34+ cells/kg (9 days versus 10 days,p = 0.01), but a dose > or =3 X 10(6) CD34+ cells/kg is necessary for reliable, rapid, and sustained neutrophil and platelet engraftment by day 21.     

Relaxant and contractile responses to prostaglandins in premature, newborn and adult baboon cerebral arteries

Dose-dependent actions of prostaglandins (PGs) were investigated on cerebral arterial strips isolated from premature, newborn and adult baboons. PGE1 an PGE2 in low concentrations (10(-9) to 10(-7) M) elicited significant relaxation in both premature and newborn baboon cerebral arteries. Arteries from adult baboons showed slight or small relaxation in response to these PGs. PGE1 and PGE2 in higher concentrations (10(-8) to 10(-6) M) caused no contraction in premature and newborn arteries, but significant contraction in adult arteries. PGF2 alpha (10(-9) to 10(-7) M) elicited relaxations in arteries from baboons of every age group, being greater in prematures and newborns than in adults. PGF2 alpha (3 X 10(-7) to 10(-5) M) produced a slight or small contraction in prematures and newborns, respectively, whereas larger contraction was induced in the adult artery. PGI2 (prostacyclin) (10(-8) to 10(-6) M) produced dose-dependent relaxation in arteries from baboons of all age groups with no significant difference in the relaxant effect among the three age groups. Effective concentration (EC25) values for relaxant effect of PGE1 and PGE2 were much less than those of PGF2 alpha and PGI2 in premature and newborn arteries. In adult cerebral arteries, only PGF2 alpha and PGI2 were effective in causing a significant relaxation. In premature and newborn arteries, PGE1 and PGE2 were not effective in causing a significant contraction, whereas in adult arteries EC25 values for contractile effects of PGE1 and PGE2 were less than those for PGF2 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of a new, more oxygen-permeable, polyvinylchloride container

A new container made of polyvinylchloride (PVC) with diethylhexyl phthalate (DEHP) used as the plasticizer was subjected to in vitro and in vivo evaluation for prolonged platelet storage. As compared with the original PVC bag, this bag has increased gas permeability by its reduced film thickness, larger surface area (400 ml capacity), and more porous label. The oxygen permeability coefficient, K(O2), of the new container was measured to be 655 nmol per min per atm. On the basis of previous studies relating the K(O2) to the maximal platelet count, it was predicted that this maximal count would be in the range of 7.9 to 8.9 X 10(10) platelets. This prediction was confirmed by carrying out 58 studies measuring pH, pO2, and platelet count on platelet concentrates (PCs) stored for up to 7 days. After 5 days of storage all PCs with counts above 8.0 x 10(10) had pH less than or equal to 7.0, whereas those with counts below 8.0 x 10(10) had pH greater than or equal to 7.0. Six units (10%) with counts above 9.0 X 10(10) had pH levels of 6.5 or below. Thirteen of the PCs underwent extensive in vitro testing of platelet function during 7 days of storage. No significant differences were found in pH, ATP content, and decrease in platelet count, as compared with studies (n = 22) using PCs stored in polyolefin containers.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vitro selection of resistance to clinafloxacin, ciprofloxacin, and trovafloxacin in Streptococcus pneumoniae

Ability of daily sequential subcultures in subinhibitory concentrations of clinafloxacin, ciprofloxacin, and trovafloxacin to select resistant mutants was studied in 10 pneumococci (ciprofloxacin MICs, 1 to 4 microg/ml, and clinafloxacin and trovafloxacin MICs, 0.06 to 0.125 microg/ml [n = 9]; ciprofloxacin, clinafloxacin, and trovafloxacin MICs, 32, 0.5, and 2 microg/ml, respectively [n = 1]). Subculturing was done 50 times, or until MICs increased fourfold or more. Mutants for which MICs were fourfold (or more) higher than those for parent strains were selected in five strains by clinafloxacin, in six strains by trovafloxacin, and nine strains by ciprofloxacin. Sequence analysis of type II topoisomerase showed that most mutants had mutations in ParC at Ser79 or Asp83 and in GyrA at Ser81, while a few mutants had mutations in ParE or GyrB. In the presence of reserpine, the MICs of ciprofloxacin and clinafloxacin for most mutants were lower (four to eight times lower), but for none of the mutants were trovafloxacin MICs lower, suggesting an efflux mechanism affecting the first two agents but not trovafloxacin. Single-step mutation rates were also determined for eight strains for which the MICs were as follows: 0.06 microg/ml (clinafloxacin), 0.06 to 0.125 microg/ml (trovafloxacin), and 1 microg/ml (ciprofloxacin). Single-step mutation rates with drugs at the MIC were 2.0x10(-9) to <1.1x10(-11), 5.0x10(-4) to 3.6x10(-9), and 4.8x10(-4) to 6.7x10(-9), respectively. For two strains with clinafloxacin MICs of 0.125 to 0.5 microg/ml trovafloxacin MICs of 0. 125 to 2 microg/ml, ciprofloxacin MICs of 4 to 32 microg/ml mutation rates with drugs at the MIC were 1.1x10(-8)-9.6x10(-8), 3.3x10(-6)-6. 7x10(-8), and 2.3x10(-5)-2.4x10(-7), respectively. Clinafloxacin was bactericidal at four times the MIC after 24 h against three parent and nine mutant strains by time-kill study. This study showed that single and multistep clinafloxacin exposure selected for resistant mutants less frequently than similar exposures to other drugs studied.     

Peroxisome proliferator-activated receptor gamma mediates protection against cyclooxygenase-2-induced gut dysfunction in a rodent model of mesenteric ischemia/reperfusion

Cyclooxygenase (COX)-2 has been identified as an important mediator elaborated during ischemia/reperfusion, with pro- and anti-inflammatory properties having been reported. As the role of COX-2 in the small intestine remains unclear, we hypothesized that COX-2 expression would mediate mesenteric ischemia/reperfusion-induced gut injury, inflammation, and impaired transit and that these deleterious effects could be reversed by the selective COX-2 inhibitor, N-[2-(cyclohexyloxy)-4-nitrophenyl] methanesulphanamide (NS-398). Additionally, we sought to determine the role of peroxisome proliferator-activated receptor gamma (PPARgamma) in mediating protection by NS-398 in this model. Rats underwent sham surgery or were pretreated with NS-398 (3, 10, or 30 mg/kg) intraperitoneally 1 h before 60 min of superior mesenteric artery occlusion and 30 min to 6 h of reperfusion. In some experiments, NS-398 (30 mg/kg) was administered postischemia. Ileum was harvested for COX-2 mRNA and protein, PGE2, myeloperoxidase (inflammation), histology (injury), intestinal transit and PPARgamma protein expression, and DNA-binding activity. COX-2 expression and PGE2 production increased after mesenteric ischemia/reperfusion and were associated with gut inflammation, injury, and impaired transit. Inhibition of COX-2 by NS-398 (30 mg/kg, but not 3 or 10 mg/kg) not only reversed the deleterious effects of COX-2, but additionally induced expression and nuclear translocation of PPARgamma. NS-398 given postischemia was equally protective. In conclusion, COX-2 may function as a proinflammatory mediator in a rodent model of mesenteric ischemia/reperfusion. Reversal of gut inflammation, injury, and impaired transit by high-dose NS-398 is associated with PPAR activation, suggesting a potential role for PPAR-gamma in shock-induced gut protection.     

泌尿系统结石成分谱及与血清TG、TC及PGE2水平的相关性

目的分析泌尿系统结石成分谱及与血清三酰甘油(TG)、总胆固醇(TC)及前列腺素E2(PGE2)水平的相关性。方法选取2015年5月至2018年12月于该院就诊的肾结石患者1875例为患者组,选取同期于该院体检合格的健康者83例为对照组。在征得受试者同意的前提下,分别于进入研究队列时刻(T0)及治疗后即入选后第90天(T1)对受试者进行血液标本采集(对照组仅采集T0时的血液标本),采用酶联免疫吸附测定(ELISA)检测血清TG、TC及PGE2水平。结果1875例患者中1677例患者的主要结石成分为草酸钙;主要结石成分为磷酸磷灰石的患者为117例;主要结石成分为尿酸的患者55例;主要结石成分为磷酸镁铵的患者23例;主要结石成分为胱氨酸的患者3例。不同结石成分患者24h尿量及尿pH值比较,差异均无统计学意义(P>0.05)。患者组和健康组血清TG、TC及PGE2水平比较,差异均有统计学意义(P<0.05)。患者组T0和T1的血清TG、TC及PGE2水平比较,差异均有统计学意义(P<0.05)。以治疗后水平为基线,血清TG、TC及PGE2水平均存在两两间的正相关(P<0.05)。草酸钙结石患者肾组织标本切片的HE染色显示,肾小管有扩张表现,且多数肾小管中存在草酸钙结晶或结晶团块。结论荆门地区泌尿系统结石成分以草酸钙为主,血清TG、TC及PGE2水平有助于泌尿系统结石的诊断;相比于其他结石成分,草酸钙结石对肾组织损伤更为明显。     

Abnormal PGE(2) regulation of monocyte TNF-alpha levels in trauma patients parallels development of a more macrophage-like phenotype

Some trauma patients' monocytes (MO) increase TNF-alpha levels concomitant to augmenting production of the TNF-alpha inhibitor prostaglandin E2 (PGE2), suggesting posttrauma MO insensitivity to PGE2 effects. This study assesses additional posttrauma MO PGE2 insensitivity effects on altering TNF-alpha form (membrane versus secreted), down-regulating MO receptor expression, and depressing MO APC function. Posttrauma MO TNF-alpha insensitivity to exogenous and autocrine PGE2 correlated to accumulation of TNF-alpha primarily as a membrane-bound cytokine (mTNF-alpha). MO retention of mTNF-alpha correlated with unfavorable clinical outcomes and loss of antigen-presenting cell (APC) function as assessed by depressed MLR and dendritic cell (DC) differentiation. MO TNF-alpha sensitivity to down-regulation by IL-10 was retained, suggesting that PGE2-related functions are specifically altered in these patients' MO. Freshly isolated MO from all trauma patients had decreased expression of Toll-like receptor 4 (TLR4) for gram-negative bacteria. Exogenous PGE2 at high (10 (-6) M) or low (10 (-8) M) concentrations decreased normals' and further decreased APC-competent patients' MO TLR4 expression but had no effect on TLR2. Patients' APC-dysfunctional MO failed to further down-regulate their TLR4 expression in response to additional PGE2, demonstrating another form of PGE2 insensitivity. One of the primary MO prostaglandin receptors, eicosanoid receptor 4 (EP4), was decreased on patients' APC dysfunctional MO, suggesting that depressed EP4 expression could contribute to PGE2 insensitivity in patients' MO. The APC dysfunctional MO's dysregulation of TLR4 expression paralleled increased macrophage-like characteristics such as increased CD64 expression density, elevated mTNF-alpha production, and increased PGE2 levels. Increased PGE2 levels still decreased patients' MO APC functions but failed to depress either MO TLR4 expression or mTNF-alpha levels, suggesting differential involvement of EP receptors in postinjury PGE2-mediated effects.     

STUDIES ON VIRULENCE : II. THE INCREASE IN VIRULENCE IN VITRO OF A STRAIN OF PNEUMOCOCCUS.

1. An automatic apparatus is described by which a new supply of food can be furnished actively growing organisms at any desired interval of time—an automatic transferring device. 2. A single strain of pneumococcus, Type I, Neufeld, which had become avirulent for mice, acquired virulence of maximal degree when grown in the described apparatus with skimmed milk sterilized in an Arnold sterilizer as the medium. Transfers were made at intervals of 2, 4, and 8 hours. It is difficult to determine the best interval of transfer, but the 8 hour interval apparently is most suitable, with the 4 and 2 hour following in preference in the order named. 3. Pasteurized skimmed milk from a single dairy, but obtained on different days, when used as medium at a 2 hour interval, varied in effect on the virulence of pneumococci, the results showing that the virulence might be either increased, decreased, or maintained. 4. Skimmed milk heated for varying lengths of time, 30 minutes at 17 pounds pressure, or 60 or 90 minutes at the same pressure, lost its suitability for maintaining virulence of a pneumococcus when transferred every 2 hours, the effect being in direct proportion to the length of time the milk was heated. 5. The H ion concentration of milk had slight effect on virulence. A virulent strain of pneumococcus was grown in milk adjusted to pH = 5, 6, 7, 8, and 9, transfers being made every 2 hours. Virulence was maintained to a like degree on milk titrated to pH = 5, 6, and 7, but when the organism was grown in milk of pH = 8 and 9, virulence decreased, more rapidly at pH = 9 than at pH = 8. 6. A pure line practically avirulent strain of pneumococcus picked by the Barber method, when grown in milk at a 4 hour interval of transfer, increased in virulence 10 million fold; that is to say, until one diplococcus would kill a mouse. Prior to this study, no record has been found in which the virulence of any microorganism has been increased to such a degree by an in vitro method.     

Differential effects of 20-hydroxyeicosatetraenoic acid on intrarenal blood flow in the rat

We recently demonstrated that endothelin-1-induced medullary vasodilation despite a potent cortical vasoconstriction in the rat kidney may be accounted for by 20-hydroxyeicosatetraenoic acid (20-HETE) production. This study characterized the effects of 20-HETE and its metabolites, 20-hydroxy prostaglandin E(2) (20-OH PGE(2)) and 20-hydroxy prostaglandin F(2alpha) (20-OH PGF(2alpha)), and the contribution of nitric oxide (NO) and prostanoids to the changes evoked in cortical blood flow (CBF) and medullary blood flow (MBF). We tested the hypothesis that 20-HETE produces qualitatively different regional hemodynamic effects in the kidney with 20-OH PGF(2alpha) or 20-OH PGE(2), accounting for the vasoconstriction or vasodilation, respectively, in the cortex and medulla. Renal intra-arterial infusion of 1, 2.5, 5, and 10 ng/min 20-HETE decreased CBF by 10 +/- 3, 24 +/- 4, 40 +/- 7, and 58 +/- 9 perfusion units (PU), respectively, but increased MBF by 4 +/- 2, 16 +/- 4, 27 +/- 3, and 41 +/- 10 PU, respectively. 20-OH PGF(2alpha) mimics the effects of 20-HETE, as did PGF(2alpha). However, 20-OH PGE(2) increased both CBF and MBF, as did PGE(2). Indomethacin (5 mg/kg) blunted the effects of 20-HETE but not that of 20-OH PGE(2) and 20-OH PGF(2alpha). However, SQ29548 ([1S-[1alpha,2alpha(Z),3alpha,4alpha]]-7-[3[[2-[(phenylamino)carbonyl[hydrazino]methyl]-7-oxabicyclo]2.2.1]hept-2-yl]-5-heptenoic acid) (0.1 mg/kg), a prostaglandin H(2)/thromboxane A(2) receptor antagonist, blunted the cortical and medullary hemodynamic effects elicited by 20-HETE, 20-OH PGE(2), 20-OH PGF(2alpha), and PGF(2alpha) but not PGE(2). N(omega)-L-nitro arginine methyl ester (5 mg/kg), the inhibitor of NO synthase, exacerbated the cortical constrictor effects of 20-HETE and 20-OH PGF(2alpha) without affecting the medullary perfusion produced by 20-HETE or its metabolites. These findings suggest that 20-HETE, through its hydroxyl metabolites, produced differential effects in the kidney. The medullary perfusion appears to be independent of NO.     

Alpha adrenergic receptors mediate angiotensin-induced prostaglandin production in the rabbit isolated vas deferens

The effect of alpha adrenergic receptor antagonists on concentration-dependent response to angiotensins II and III was examined in the electrically stimulated isolated rabbit vas deferens. The force generated by a nonadrenergic neural mechanism was reduced by both peptides whereas the force generated by adrenergic neural mechanisms was enhanced. Angiotensin III-induced inhibition of the nonadrenergic contraction was significantly greater than that of angiotensin II for all groups. Yohimbine (1 X 10(-4) M), an alpha-2 receptor antagonist, attenuated the depression of the nonadrenergic contraction produced by angiotensins II and III. Yohimbine (1 X 10(-5) and 1 X 10(-4) M) also significantly reduced angiotensin II-induced prostaglandin E (PGE) synthesis. Yohimbine only significantly altered the angiotensin III-induced PGE synthesis at an antagonist concentration of 1 X 10(-4) M. Rauwolscine (1 X 10(-8) and 1 X 10(-7) M) attenuated angiotensin II-induced PGE production and at a higher concentration (1 X 10(-6) M) reduced angiotensin III-induced PGE production. The alpha-1 antagonist, prazosin (1 X 10(-6) M), did not alter nonadrenergic contractile or PGE responses to either angiotensin. The alpha-2 agonist, clonidine, both inhibited the nonadrenergic neural contraction and enhanced PGE synthesis. We interpret these data to indicate that angiotensins II and III may act via separate mechanisms to induce PGE synthesis in the vas deferens, with angiotensin II effects being more dependent on norepinephrine release from adrenergic nerves.