Evaluation of Strategies for the Assessment of Drug-Drug Interactions Involving Cytochrome P450 Enzymes.

BACKGROUND AND OBJECTIVES: Drug-drug interactions (DDIs) can occur when one drug alters the metabolism of another drug. Drug metabolism mediated by cytochrome P450 enzymes (CYPs) is responsible for the majority of metabolism of known drugs and inhibition of CYP enzymes is a well-known cause of DDIs. In the current study, the use of various human liver microsomes (HLM)-based methods to determine occurrence of CYP-mediated metabolism-dependent inhibition (MDI) and possible follow-up studies were evaluated. METHODS: Human CYP inhibition was studied using the following methodologies: direct inhibition and (non-diluted) IC50-shift assays, a ferricyanide-based reversibility assay, a spectrophotometric metabolic intermediate complex (MIC) assay, and recording of reduced carbon monoxide (CO)-difference spectra. HLM incubations in the presence and absence of NADPH and glutathione (GSH) were performed to study the possible formation of CYP-dependent GSH adducts. HLM incubations with the radiolabeled inhibitors mifepristone and paroxetine were performed to study CYP-mediated covalent binding. RESULTS: Dihydralazine and furafylline displayed irreversible MDI of CYP1A2. Paroxetine displayed both quasi-irreversible and irreversible MDI of CYP2D6, formation of CYP-dependent GSH adducts was observed, while CYP-mediated covalent binding occurred which was decreased in the presence of GSH. Mifepristone displayed irreversible MDI of CYP3A4, formation of CYP-dependent GSH adducts was observed, while CYP-mediated covalent binding occurred which was decreased in the presence of GSH. Troleandomycin and verapamil displayed quasi-irreversible MDI of CYP3A4; MIC formation was observed, while no formation of CYP-dependent GSH adducts occurred. CONCLUSIONS: This study gives a representative overview of current methodologies that can be used to study CYP inhibition. The here presented strategy can be applied as a tool during risk evaluation of CYP-mediated DDIs.

Determination of dihydralazine based on chemiluminescence resonance energy transfer of hollow carbon nanodots.

The famous weak chemiluminescence (CL) system of potassium permanganate and sodium bisulfite (KMnO4-HSO3-) was enhanced by the hollow fluorescent carbon nanodots (HCNs). The investigation of mechanism revealed that the enhanced CL was induced by the excited-state HCNs (HCNs⁎), which could be produced from the electron-transfer annihilation of positively charged HCNs (HCNs+) and negatively charged HCNs (HCNs-) as well as by CL resonance energy transfer (CRET) from excited SO2 (SO2⁎)/1O2 to HCNs. The dihydralazine sulfate (DHZS) had a diminishing effect on the CL of HCNs-KMnO4-HSO3- system due to the competitive consumption of O2-. Under the optimal conditions, the reduced CL signal with the concentration of DHZS was linear in the range of 1.0×10-7-7.0×10-5mol/L with a detection limit of 3.0×10-8mol/L. The relative standard deviation for seven repeated determination of 5.0×10-6mol/L DHZS was 2.1%. The established method was applied to the determination of DHZS in pharmaceutical preparations, human urine and plasma samples with good precision and accuracy.

Ketanserin versus dihydralazine for the treatment of severe hypertension in early-onset preeclampsia: a double blind randomized controlled trial.

OBJECTIVE: Determine the definitive position of ketanserin and dihydralazine for treatment of severe hypertension in pregnancy. STUDY DESIGN: A single centre double blind randomized controlled trial was performed at the obstetrical tertiary high care unit of the University Medical Centre in Rotterdam, the Netherlands. Women with severe hypertension in pregnancy (diastolic blood pressure (DBP)≥110mmHg), and significant proteinuria (≥300mg/24h), and gestational age≤32 weeks were eligible for the study. All patients (n=30) received two infusions (double dummy technique): one contained the active ingredient (ketanserin or dihydralazine), the other was used for placebo. Nicardipine was used as rescue medication. The main outcome measures were persistent severe hypertension (DBP>100mmHg>120min) despite maximum dosage of study medication and prolongation of pregnancy. RESULTS: Dihydralazine was significantly more effective in lowering blood pressure than ketanserin. No significant difference in prolongation of pregnancy was seen between the two groups. After 30 inclusions, the study was stopped because of the high rate of persistent hypertension using ketanserin and the high rate of maternal side effects using dihydralazine and the apparent succesful use of the rescue drug nicardipine. CONCLUSIONS: Our results do not support the use of either dihydralazine or ketanserin for the treatment of severe hypertension in pregnancy. Future research is needed to compare nicardipine with other antihypertensive drugs currently in use for treatment of severe hypertension in pregnancy.

Measurement of hyper- and hypotension during repeated dose toxicity studies in either freely moving or physically restrained cynomolgus monkeys.

INTRODUCTION: The measurement of cardiovascular endpoints in standard toxicology studies remains a challenge as the routinely used non-invasive methods require physical restraint, causing an increase of sympathetic neural activity, leading to excitement and potentially hypertension in the experimental animals. In this study, a miniature telemetry blood pressure transmitter was used to evaluate if the acute hyper- and hypotension could be detected in free moving cynomolgus monkeys as well as physically restrained animals using positive control drugs. Furthermore, as a comparator, routine high definition oscillometry (HDO) was performed in restrained animals. METHODS: Hemodynamic parameters were monitored continuously from conscious, freely moving animals following oral administration of vehicle (water) or 1 and 10mg/kg of etilefrine, and 1 and 4mg/kg of dihydralazine as positive control articles. A second dose session was performed to confirm the reproducibility of results and a third dose session combined with physical restraint procedures for blood collection and HDO measurements. RESULTS: There was a dose-dependent, statistically significant increase in the systolic blood pressure following oral doses of etilefrine at all 3 dose sessions. This effect was less apparent during session 3, probably due to the physical restraint applied for the blood sampling and HDO measurement. No differences in the blood pressure were measured using HDO. On all three dose sessions following oral doses of dihydralazine the expected statistically significant decrease in the diastolic pressure could be clearly measured even when the telemetric data recordings were combined with physical restraint. DISCUSSION: Due to the advantages of the minimally invasive telemetry technique compared to HDO and the possibility of prolonged measurement periods, it is an invaluable tool for blood pressure measurement in freely moving animals in toxicology studies.

Common variants in TGFBR2 and miR-518 genes are associated with hypertension in the Chinese population.

BACKGROUND: An animal study reported that TGF-ß1 maturation was linked to the homeostasis of blood pressure and elastogenesis of essential hypertension (EH). Recent advances require further research of TGF-ß1 receptor in EH. METHODS: A case-control study comprised of 2,012 adult hypertension case patients and 2,210 adult control subjects was conducted, and the association with blood pressure was further tested in children. Logistic regression and calculated genetic risk score were used to evaluate the effects of one single nucleotide polymorphism (SNP) and multiple SNPs on EH, respectively. RESULTS: The genetic risk score of 10 SNPs showed a significant association with hypertension; the odds ratio of the upper quartile vs. the lower quartile was 1.282 (P = 4.67 × 10(-3)). rs7256241 in miR-518 was significantly associated with diastolic blood pressure (DBP) change in control subjects (P = 0.002), and this association was also observed in children (P = 0.04). The systolic blood pressure (SBP) and DBP of female patients taking reserpine were higher with the C and G alleles of rs3773661 (P = 0.004) and rs7256241 (P = 0.002), respectively. In patients taking Zhen Ju Jiang Ya tablets, SBP and DBP decreased linearly with rs749794 (P = 0.004 and P = 0.048, respectively). SBP decreased linearly with rs1155705 (P = 0.007) and rs11709624 (P = 0.04), but increased with rs1036096 (P = 0.03) in male patients. In male patients taking Jiang Ya tablets, SBP increased linearly with rs11709624 (P = 0.007), DBP increased linearly with rs1155705 (P = 0.03) whereas decreased with rs7256241 (P = 0.04). CONCLUSIONS: Our results suggest that TGFBR2 and miR-518 harbor variants that increase the risk of EH and affect blood pressure homeostasis as well as efficacy of antihypertensive agents.

The differential effects of recombinant brain natriuretic peptide, nitroglycerine and dihydralazine on systemic oxygen delivery and gastric mucosal microvascular oxygenation in dogs.

Brain natriuretic peptide has vasodilatory properties and may thus increase splanchnic perfusion and oxygenation. We compared the effects of recombinant brain natriuretic peptide on gastric mucosal microvascular haemoglobin oxygenation (reflectance spectrophotometry) and systemic variables with those of equi-hypotensive doses of two other vasodilators (nitroglycerine and dihydralazine). Chronically instrumented, healthy dogs were randomly allocated to receive on different days, one of the three drugs (nitroglycerine and dihydralazine doses titrated to reduce mean arterial pressure by ∼20%). Brain natriuretic peptide significantly increased gastric mucosal microvascular haemoglobin oxygenation selectively, i.e. without concomitant haemodynamic effects. In contrast, the other vasodilators either did not increase gastric mucosal microvascular haemoglobin oxygenation at all (nitroglycerine), or did so only with marked increases in other systemic haemodynamic variables (dihydralazine). Our data suggest a potential role of recombinant brain natriuretic peptide selectively for increasing microvascular mucosal oxygenation. Studies are required to extend these findings to the clinical setting.

Long-term efficacy and tolerability of a fixed-dose combination of antihypertensive agents: an open-label surveillance study in China.

BACKGROUND: A fixed-dose combination (FDC) of four compounds, hydrochlorothiazide 12.5 mg, triamterene 12.5 mg, dihydralazine 12.5 mg and reserpine 0.1 mg (HTDR), is widely used as an antihypertensive treatment in China. Although HTDR has been used in China for more than 30 years, there have been few comprehensive evaluations of this treatment. OBJECTIVE: The aim of this study was to investigate the long-term efficacy and tolerability of HTDR in Chinese patients with essential hypertension. METHODS: This was a 36-month, community-based, open-label surveillance study, conducted in the Huangpu District (Shanghai, China). The study was based in local primary healthcare settings. Subjects were recruited if they had essential hypertension, were aged ≥35 years at the time of enrolment, were expected to remain in the area for 3 years, and were able to provide informed consent. Patients who had secondary hypertension, myocardial infarction or stroke within 6 months of screening, impaired renal or hepatic function, history of cardiomyopathy or chronic heart failure, or were pregnant or lactating were excluded. HTDR was administered as one or two tablets per day in the morning. If necessary, additional hydrochlorothiazide was added. Blood pressure (BP) was measured at baseline and throughout the 36-month surveillance period every 3 months. Biochemical indicators (e.g. fasting blood glucose, plasma lipid parameters, plasma sodium and potassium, plasma uric acid and serum creatinine) were also measured, and adverse events were noted. BP reductions and the rate at which patients achieved BP targets (systolic BP [SBP] <140 mmHg and diastolic BP [DBP] <90 mmHg) throughout the period were determined. Subgroup analyses by sex and age were also conducted. RESULTS: A total of 1529 patients (550 male, 979 female; mean age 65.7 years) entered the study. After the 36-month treatment period, 93.1% of patients had achieved the SBP target, 97.9% had achieved the DBP target, and 92.1% had achieved both. The mean decreases in SBP and DBP were 15.3 mmHg and 9.9 mmHg, respectively. Overall, 127 adverse events in 119 patients (7.8%) occurred during the follow-up period, most of which were mild to moderate. Plasma lipid profiles were improved after 24 months of treatment. In addition, a significant increase in plasma potassium and a significant reduction in plasma uric acid were seen. CONCLUSION: HTDR was found to have good long-term efficacy and tolerability in Chinese patients with essential hypertension.

Flow-injection chemiluminescence determination of dihydralazine sulfate in serum using luminol and diperiodatocuprate (III) system.

A novel flow-injection chemiluminescence (CL) method for the determination of dihydralazine sulfate (DHZS) is described. The method is based on the reaction of luminol and diperiodatocuprate (K(2)[Cu(H(2)IO(6))(OH)(2)], DPC) in alkaline medium to emit CL, which is greatly enhanced by DHZS. The possible CL mechanism was first proposed based on the kinetic characteristic, CL spectrum and UV spectra. The optimum condition for the CL reaction was in detail studied using flow-injection system. The experiments indicated that under optimum condition, the CL intensity was linearly related to the concentration of DHZS in the range of 7.0x10(-9) to 8.6x10(-7) g mL(-1) with a detection limit (3sigma) of 2.1x10(-9) g mL(-1). The proposed method had good reproducibility with the relative standard deviation 3.1% (n=7) for 5.2x10(-8) g mL(-1) of DHZS. This method has the advantages of simple operation, fast response and high sensitivity. The special advantage of the system is that very low concentration of luminol can react with DPC catalyzed by DHZS to get excellent experiment results. And CL cannot be observed nearly when luminol with same concentration reacts with other oxidants, so luminol-DPC system has higher selectivity than other luminol CL systems. The method has been successfully applied to determine DHZS in serum.

Effects of dihydralazine on renal water and aquaporin-2 excretion in humans.

OBJECTIVE: Dihydralazine is a vasodilator that lowers blood pressure, but often also leads to significant water and sodium retention. To characterize the effect of dihydralazine on renal sodium and water handling, we tested the hypothesis that dihydralazine causes water retention parallel with an increase in urinary excretion of aquaporin-2 (u-AQP2) in healthy humans. MATERIAL AND METHODS: The effect of intravenous infusion of dihydralazine in three doses (3.125 mg, 6.250 mg and 9.375 mg) on urinary AQP2, water and sodium excretion, heart rate (HR), blood pressure (BP) and vasoactive hormones was measured in a randomized, placebo-controlled, double-blind, crossover study in 17 healthy subjects. Glomerular filtration rate (GFR) and renal tubular function were determined with the continuous infusion clearance technique and vasoactive hormones with radioimmunoassays. RESULTS: Dihydralazine compared to placebo had no impact of u-AQP2 (effect of dihydralazine versus placebo +/-SE) (-0.074+/-0.048 ng/min versus -0.015+/-0.034 ng/min; p = 0.42), despite significant reductions in urine output and free water clearance after 9.375 mg of dihydralazine. Dihydralazine significantly lowered BP and increased HR, plasma levels of angiotensin II and (except after 3.125 mg) atrial natriuretic peptide, while plasma levels of vasopressin, GFR and fractional excretions of sodium and lithium were not significantly changed. CONCLUSIONS: These findings suggest that dihydralazine increases water re-absorption in the distal tubules, independently of vasopressin and of sodium re-absorption. Furthermore, our study does not support an effect of the sympathetic nervous system, the renin-angiotensin system and the natriuretic peptide system on u-AQP2 regulation.

Chemiluminescence investigation of carbon dioxide-enhanced oxidation of dihydralazine sulfate by peroxynitrite and its application to pharmaceutical analysis.

A weak chemiluminescence (CL) emission was observed upon mixing peroxynitrite (ONOO(-)) with dihydralazine sulfate (DHZS). Further experiments showed that carbonate media could enhance the CL emission significantly. Based on these observations, a novel flow injection CL method for the determination of DHZS is developed. The CL signal is linearly with DHZS concentration in the range of 0.01-3.0 microg mL(-1) with a detection limit of 3.6 ng mL(-1). The method was applied to the analysis of DHZS in pharmaceutical preparations and compared well with the high-performance liquid chromatography (HPLC) method. The CL mechanism is discussed and it is postulated that it involves nitrosoperoxocarboxylate (ONOOCO(2)(-)), which is an unstable adduct and can rapidly decompose into *NO(2) and *CO(3)(-) radical. The latter can then oxidize DHZS to give out strong CL emission.

Regression of glomerulosclerosis in subtotally nephrectomized rats: effects of monotherapy with losartan, spironolactone, and their combination.

Angiotensin II accelerates and renin-angiotensin system blockade halts progression; blockade with high doses even reverses established glomerulosclerosis. Aldosterone also accelerates progression of glomerulosclerosis, partially independently of angiotensin II. The purpose of this study was to assess the relative ability of an angiotensin receptor type 1 (AT1) blocker, a mineralocorticoid receptor blocker, and their combination to reverse glomerulosclerosis. Sprague-Dawley rats were subjected to subtotal renal ablation (SNX) or sham operation. Eight weeks after surgery, they were either euthanized or allocated to treatment with vehicle, losartan, spironolactone, their combination, or unspecific antihypertensive treatment (dihydralazine) for 4 wk. Renal morphology was evaluated by stereology in tissues obtained using pressure-controlled perfusion fixation. Systolic blood pressure was significantly higher in SNX compared with sham-operated animals and decreased in all treatment groups. Compared with wk 8 after SNX, the glomerulosclerosis index (GSI) had increased further by week 12 in the vehicle- and dihydralazine-treated groups but was significantly lowered in the SNX+losartan as well as in the SNX+losartan+spironolactone groups and had not progressed further in the SNX+spironolactone group. The study confirms the partial regression of established glomerulosclerosis in subtotally nephrectomized rats after high-dose AT1 receptor blockade. Nonhyperkalemic doses of spironolactone prevented the increase but failed to decrease the GSI below the 8-wk level and preserved podocyte numbers. Combining the AT1 blocker with mineralocorticoid receptor blockade failed to further increase the regression of glomerulosclerosis.

Maternal and fetal hemodynamic effects induced by nitric oxide donors and plasma volume expansion in pregnancies with gestational hypertension complicated by intrauterine growth restriction with absent end-diastolic flow in the umbilical artery.

OBJECTIVE: To evaluate the effect of plasma volume expansion (PVE) and nitric oxide (NO) donors, in addition to antihypertensive therapy for gestational hypertensive pregnancies complicated by intrauterine growth restriction (IUGR) with absent end-diastolic flow (AEDF) in the umbilical artery (UA). METHODS: This was a case-control study into which 32 gestational hypertensive pregnancies with IUGR and AEDF were enrolled. Sixteen of these were treated with antihypertensive drugs, NO donors and PVE (Group A), and 16, matched for maternal age, gestational age and fetal conditions, were treated with antihypertensive drugs only (Group B). All patients underwent fetal and uteroplacental assessment and maternal echocardiography to evaluate total vascular resistance (TVR) and cardiac output before and 5-14 days after initiation of treatment. RESULTS: After 5-14 days of treatment, the maternal TVR in Group A fell from 2170 +/- 248 to 1377 +/- 110 dynes.s.cm(-5) (P < 0.01), and that in Group B fell from 2090 +/- 260 to 1824 +/- 126 dynes.s.cm(-5) (P < 0.01), with the reduction being greater in Group A than in Group B (P < 0.01). There was a significant increase in cardiac output in Group A after 5-14 days of treatment vs. baseline (6.19 +/- 0.77 vs. 4.32 +/- 0.66, P < 0.001), and, after treatment, cardiac output was significantly greater in Group A than it was in Group B (6.19 +/- 0.77 vs. 4.70 +/- 0.44, P < 0.001). Reappearance of end-diastolic flow in the UA occurred in 14/16 patients in Group A but in no patients in Group B (87.5% vs. 0%, P < 0.05). The interval between detection of UA-AEDF and delivery was 28 +/- 16 days in Group A and 11 +/- 6 days in Group B (P < 0.05). CONCLUSION: Administration of NO donors and PVE in gestational hypertensive pregnancies affected by IUGR and UA-AEDF appears to improve both maternal and fetal hemodynamics, inducing prolongation of gestation.

Progress curve analysis of CYP1A2 inhibition: a more informative approach to the assessment of mechanism-based inactivation?

Mechanism-based cytochrome P450 inactivation is defined as a time- and NADPH-dependent inactivation that is not reversible upon extensive dialysis. Current methodologies use dilution approaches to estimate the rate of inactivation and offer limited mechanistic insight and are significantly influenced by experimental conditions. We investigated the potential of progress curve analysis because this experimental design allows investigation of both the reversible (K(iapp)) and irreversible (K(i), K(inact)) components of the reaction mechanism. The human liver microsomal CYP1A2 inactivation kinetics of resveratrol, oltipraz, furafylline, and dihydralazine (Fig. 2) were evaluated. The inactivation results for furafylline (K(i), 0.8 microM; K(inact), 0.16 min(-1)) are within 2-fold to published data (K(i), 1.6 microM; K(inact), 0.19 min(-1)). Resveratrol and dihydralazine results are within a 4.3-fold range of published data, which compares well with ranges of estimates of these parameters across publications (e.g., furafylline has estimates ranging of K(i) from 1.6 to 22.3 microM and K(inact) from 0.19 to 0.87 min(-1)). This range of estimates highlights the potential caveats surrounding the existing methodologies that have been previously discussed in depth. In addition to these inactivation parameters, we have been able to demonstrate a variation in balance of reversible versus irreversible inhibition within these inactivators. Oltipraz and resveratrol have K(iapp) values similar to their K(i), indicating a significant early onset reversible inhibition, whereas furafylline and dihydralazine are dominated by irreversible inactivation. This approach allows a more mechanistic investigation of an inactivator and in the future may improve the prediction of clinical drug-drug interactions.

Method development for dihydralazine with HPLC-MS/MS--an old but tricky substance in human plasma.

An HPLC-MS/MS method was developed and validated for the determination of dihydralazine in human plasma. HPLC-MS/MS has not been used before in a published paper and provides better sensitivity and selectivity. Therefore a much easier sample preparation than published before is feasible (protein precipitation). As this substance is rather reactive and sensitive some specific care has to be taken hindering the conversion of the substance in whole blood and following human plasma after blood withdrawal. Hydrazines often are used for derivatization of aldehydes and ketones. With specific care (using 1,4-dithiothreitol (DTT) and cooling) dihydralazine can be preserved and analysed without decomposition or conversion in the tested range of 0.500-302 ng/mL of human plasma. The following inter-batch precision and accuracy of the Quality Control Samples resulted: QC-A (1.34 ng/mL plasma) with a precision of coefficient of variation (CV) 7.66% and an accuracy of 103.2%; QC-B (18.2 ng/mL 7.86%, acc. 101.3%); QC-C (258 ng/mL, 9.73%, acc. 98.3%). The inter-batch values of the LLOQ samples at 0.500 ng/mL were 7.17% for CV and accuracy of 106.4%. Mean recovery tested at the QC levels was found to be 103.8%. Specificity in six different plasma samples was good (<10% of the area of the LLOQ). Stability in plasma was tested under different conditions and was sufficient.

Dihydralazine treatment limits liver injury after hemorrhagic shock in rats.

OBJECTIVE: Impaired hepatic perfusion after hemorrhagic shock frequently results in hepatocellular dysfunction associated with increased mortality. This study characterizes the effect of the vasodilators dihydralazine and urapidil on hepatocellular perfusion and integrity after hemorrhagic shock and resuscitation. DESIGN: Prospective, randomized, controlled experimental study. SETTING: University experimental laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: To register systemic and regional hepatic hemodynamics, rats (n=6 per group) were instrumented and randomly assigned to the following groups: shock+vehicle; shock+dihydralazine (1.5 mg/kg); or shock+urapidil (3 mg/kg). After 1 hr of hemorrhagic shock, animals were resuscitated for 5 hrs and mean arterial pressure was maintained at 70+/-5 mm Hg by administration of dihydralazine or urapidil. To evaluate hepatic heme oxygenase-1 expression and liver injury (determination of levels of alanine and aspartate aminotransferase [ALT, AST] and histology), an additional series of experiments with six animals per group was performed. At the end of each experiment, animals were killed and blood and liver tissue was obtained for subsequent analyses. MEASUREMENTS AND MAIN RESULTS: Dihydralazine increased cardiac output and portal and hepatic microvascular flow (p<.05) and reduced liver injury after shock (lower ALT and AST levels [p<.05]; improvement of histopathological changes). In contrast, urapidil had no effect on portal flow or liver injury. Hepatic heme oxygenase-1 mRNA expression was upregulated in animals subjected to hemorrhagic shock but did not differ among experimental groups. CONCLUSIONS: Dihydralazine increases nutritive portal and hepatic microvascular flow and limits liver injury after hemorrhagic shock. This protective effect appears to be the result of increased cardiac output and increased portal flow. These findings may offer a new strategy for hepatic protection after hemorrhagic shock.

Changes in metabolism and blood flow following catecholamine stimulation in the synovial membrane measured with microdialysis.

Adrenergic reactions could mediate metabolic and circulatory changes in the synovial membrane following knee surgery. The interstitial fluid of the synovial membrane and subcutaneous adipose tissue (reference) was monitored in vivo with microdialysis following knee arthroscopy with adrenaline added to the dialysis solvent, adrenaline together with a local anestetic added intra-articularly and without. Local metabolism and blood flow were measured. There was a similar increase, about two fold, in dialysate lactate in all three experimental conditions in the synovial membrane but no change in adipose tissue. Glucose and blood flow decreased by approximately 50% and 10% in both tissues following addition of adrenaline to the dialysate but no changes in the glucose concentrations or blood flow were observed in the other two experimental situations. As regards glycerol the addition of adrenaline caused an approximate 20% increase of the concentration in adipose tissue but an approximate 20% decrease in the synovial membrane. The intra-articular injection caused an approximate 50% increase of the glycerol level in the synovial membrane but no change in adipose glycerol. Thus, the hypermetabolic state in the synovial membrane following standard arthroscopy and the tissue damage (increased glycerol level) in the synovial membrane following postoperative pain relief by intra-articularly injected local anesthetics together with adrenaline doesn't enhance the hypermetabolic state seen postoperatively without adrenaline. However, catecholamines have pronounced in vivo effects on metabolism and blood flow in the synovial membrane.

Antihypertensive therapy in patients with pre-eclampsia: A prospective randomised multicentre study comparing dihydralazine with urapidil.

BACKGROUND: Drug treatment is imperative for pregnant women with pregnancy-induced hypertension (PIH) and pre-eclampsia. For more than 40 years, dihydralazine has been the drug of choice for this indication. Another particularly effective and better tolerable antihypertensive is urapidil. Yet only a few studies on limited patient collectives have been published on the clinical experience with urapidil in PIH. METHODS: Urapidil was interindividually compared to dihydralazine in a total of 42 patients, at six participating clinical centres. Patients were randomly assigned to the treatment groups. Urapidil was administered at an initial dose of 12.5-25mg, dihydralazine was administered at a uniform initial dose of 5mg. Patients were closely monitored for the initial 24h of therapy. Until delivery and in the postpartal phase, mother and baby underwent four additional follow-up checks at regular intervals. RESULTS: Either drug was effective in lowering BP. Urapidil treatment proved to be better controllable. There were clear differences as to tolerability. In the urapidil group, one patient complained of headaches. In the dihydralazine group, six patients experienced adverse occurrences. Under dihydralazine treatment, some marked HR increases occurred, interpretable as reflectory tachycardia. CONCLUSIONS: Urapidil proved to be equally effective as dihydralazine in lowering BP in patients with pre-eclampsia, but showed a better controllability and tolerability. Urapidil can hence be recommended as a promising alternative for patients with PIH.

Morbidity and development in childhood of infants born after temporising treatment of early onset pre-eclampsia.

OBJECTIVE: To assess morbidity and development in childhood of infants born after temporising management of severe early onset pre-eclampsia. DESIGN: Cohort study with matched controls. SETTING: University centre for high risk obstetrics. SAMPLES: Three groups of neonates matched for gender and year of birth: one born after temporising treatment of severe early onset (<32 weeks) pre-eclampsia with an average delay of delivery of two weeks (n= 193); one born at the duration of pregnancy [1 week] of the pre-eclamptic mother on admission (control group I, n = 192); and one born at the same gestational age [1 week] as the infant of the pre-eclamptic mother (control group II, n= 189). METHOD: Follow up at four years of age or more using medical records and questionnaires. MAIN OUTCOME MEASURES: The presence of various morbidities including mental retardation, cerebral palsy, motor skill problems, visual handicap, hearing loss, speech and language problems, education level and acute or chronic respiratory problems. RESULTS: Median follow up of seven years (range 4-12) was achieved in 159 infants in the study group (83%), 122 in control group I (64%) and 110 in control group II (58%). Missing data analysis showed no differences in neonatal characteristics and morbidity between infants with and without follow up in the study group. All major and minor handicaps were less frequent in the study group than in control group I but statistical significance was reached only for acute and chronic respiratory disorders in the study group (13.8%) compared with control group I (27%). CONCLUSION: Average delay of delivery of two weeks with temporising management in severe early onset pre-eclampsia is associated with a reduced risk of respiratory disorders in childhood.

Hypertension in children with chronic renal failure.

Systemic hypertension (HTN) is one of the major problems associated with chronic renal failure (CRF). HTN is a symptom and complication of CRF. The prevalence of HTN varies with the cause of CRF. The incidence of HTN increased up to 90% with progressive deterioration of the glomerular filtration rate (GFR). HTN is the major risk factor for decline in renal function and progression of CRF. It is the most important risk factor for cardiovascular diseases and morbidity and mortality in patients with CRF and end-stage renal disease (ESRD) on dialysis. The target blood pressure for hypertensive children with CRF should be under the 95th percentile for sex and age. The therapeutic approach in CRF is directed at reducing volume expansion and sodium retention, and decreasing peripheral vascular resistance. Diuretics are first-line therapy for HTN in patients with CRF with sodium and water retention. ACE inhibitors are the first-class drugs because of their renoprotective effect in preventing deterioration of kidney function. Calcium channel blockers are excellent first-line antihypertensive drugs. Recently angiotensin II receptor blockers and ACE inhibitors have been efficiently used together for the treatment of HTN and to prevent further decline in renal function.

[Determination of five components in compound hypotensive tablet by HPLC].

AIM: To establish a method for the determination of the five components (reserpine, chlordiazepoxide, hydrochlorothiazide, dihydralazine sulfate, triamterene) in compound hypotensive tablet. METHODS: The chromatography was performed using a CN column with acetontrile-0.1 mol L(-1) sodium heptasulfonate solution (7:3) and (5:5) as the mobile phases. The detection wavelength was 267 nm for reserpine, chlordiazepoxide and hydrochlorothiazide, 310 nm for dihydralazine sulfate, 360 nm for triamterene. RESULTS: The linear range of each component was tested, and the recovery and stability of each component was satisfactory, three lots of samples were determined using the method. CONCLUSION: This is an accurate and credible quality control method for compound hypotensive tablet.