The heart in dermatomyositis and polymyositis

We studied eleven consecutive patients: eight with Dermatomyositis (DM) and three with Polymyositis (PM) from the cardiological point of view through non invasive methods. Nine patients (82%) had some kind of cardiopulmonary complications as shown by any of the used methods. Symptoms: eight (73%) referred some kind of cardiopulmonary symptoms, mainly dyspnea; Physical examination; in seven (64%) was abnormal, detecting increased second pulmonary sound in four (36%), findings of mitral valve prolapse (MVP) in two (18%) and in two (18%) S3 gallop; Electrocardiogram: in seven (64%) was abnormal; six (55%) had some kind of heart enlargement corresponding four (36%) to right atrial or ventricular hypertrophy (RAH & RVH) and two (18%) to left ventricular hypertrophy (LVH), three (27%) had incomplete or complete right bundle branch block, one (9%) had bifascicular block and one (9%) left anterior hemiblock. Two (18%) had sinus tachycardia and two (18%) atrial premature contractions; d) chest ray: six (55%) were abnormal, among them, three (27%) had pulmonary fibrosis, three (27%) had RAH and/or RVH, two (18%) had LVH and one (9%) pericardial effusion; e) Echocardiogram: was abnormal in eight (73%), corresponding three (27%) to RVH, three to MVP which has been considered rare, in two (18%) congestive cardiomyopathy, in two (18%) pericardial effusion and in one (9%) type "A" paradoxical septal movement.     

Activation of D3 dopamine receptor decreases angiotensin II type 1 receptor expression in rat renal proximal tubule cells

The dopaminergic and renin angiotensin systems interact to regulate blood pressure. Disruption of the D(3) dopamine receptor gene in mice produces renin-dependent hypertension. In rats, D(2)-like receptors reduce angiotensin II binding sites in renal proximal tubules (RPTs). Because the major D(2)-like receptor in RPTs is the D(3) receptor, we examined whether D(3) receptors regulate angiotensin II type 1 (AT(1)) receptors in rat RPT cells. The effect of D(3) receptors on AT(1) receptors was studied in vitro and in vivo. The D(3) receptor agonist PD128907 decreased AT(1) receptor protein and mRNA in WKY RPT cells and increased it in SHR cells. PD128907 increased D(3) receptors in WKY cells but had no effect in SHR cells. D(3)/AT(1) receptors colocalized in RPT cells; D(3) receptor stimulation decreased the percent amount of D(3) receptors that coimmunoprecipitated with AT(1) receptors to a greater extent in WKY than in SHR cells. However, D(3) receptor stimulation did not change the percent amount of AT(1) receptors that coimmunoprecipitated with D(3) receptors in WKY cells and markedly decreased the coimmunoprecipitation in SHR cells. The D(3) receptor also regulated the AT(1) receptor in vivo because AT(1) receptor expression was increased in kidneys of D(3) receptor-null mice compared with wild type littermates. D(3) receptors may regulate AT(1) receptor function by direct interaction with and regulation of AT(1) receptor expression. One mechanism of hypertension may be related to increased renal expression of AT(1) receptors due decreased D(3) receptor regulation.     

The analysis of quantitative expression of somatostatin and dopamine receptors in gastro-entero-pancreatic tumours opens new therapeutic strategies

OBJECTIVE: Somatostatin (sst) are present in the majority of gastro-entero-pancreatic (GEP) tumours. Effects of somatostatin receptor (sst) analogues are partial and of limited duration. Cell lines derived from GEP express dopaminergic receptors D(2). New chimeric analogues simultaneously recognising sst(2) and sst(5) or sst(2) and D(2) have additive effects in inhibition of GH and prolactin secretion in pituitary adenomas. Our aim was to quantify the expression of sst and D(2) mRNA in human GEP tumours. DESIGN AND METHODS: mRNA expression of sst(1), sst(2), sst(3) and sst(5) as well as D(2), was analysed using real-time PCR (TaqMan probe) in a series of 35 patients with GEP tumours (pancreas (n = 19) and intestinal (n = 16)). Levels of expression were compared with a group of 13 somatotroph adenomas. RESULTS: All GEP tumours express sst(1), sst(2) and D(2). Expression of sst(3) and sst(5) was observed in 89 and 76% of tumours respectively with highly variable levels. sst(2) mRNA expression was higher in nonfunctional tumours (P < 0.009) and sst5 was higher in pancreatic than in intestinal tumours (P < 0.02). Whereas sst(2) levels were similar between GEP and somatotroph tumours, levels of sst(5) and D(2) were higher in the former (394.9 +/- 156.1 x 10(-2) vs 69.7 +/- 19.5 x 10(-2) copy/copy beta-Gus (P < 0.0036) and 519.6 +/- 121.2 x 10(-2) vs 50.0 +/- 21.6 x 10(-2) copy/copy beta-Gus (P < 0.0001) respectively). In small tumours ( < 30 mm), sst(2) density appeared as a crucial parameter in somatostatin receptor scintigraphy results, whereas in big tumours, a consistent bias in SRS results was introduced by the size. In pancreatic GEP, high-level sst(3) expression was found in tumours with more active angiogenesis (higher microvessel density and vascular endothelial growth factor expression (P < 0.03)). CONCLUSIONS: GEP tumours co-express sst(2) and D(2) in 100% of cases and sst(5) in 89% thus supporting the testing of bi-specific agonists (sst(2)/sst(5) or sst(2)/D(2)) in these tumours.     

Hydrogen peroxide in the Burkitt's lymphoma cell line Raji provides protection against arsenic trioxide-induced apoptosis via the phosphoinositide-3 kinase signalling pathway

Many anticarcinogenic drugs kill tumour cells by inducing apoptosis. We examined the effects of hydrogen peroxide (H(2)O(2)) on arsenic trioxide (As(2)O(3))-induced cell killing. Low concentrations of H(2)O(2) (200 micromol/l) inhibited the ability of As(2)O(3) to induce apoptosis in the Burkitt's lymphoma cell line Raji. H(2)O(2) altered the form of cell death from apoptosis to pyknosis/necrosis and also lowered the degree of cell killing by As(2)O(3). H(2)O(2) was capable of preventing caspase-3 activation induced by As(2)O(3) in Raji cells. Incubation of cells with a phosphoinositide-3 kinase (PI-3K) inhibitor, wortmannin (100 nmol/l), blocked the effects of H(2)O(2) on As(2)O(3)-induced caspase-3 activation. In addition, the PI-3K inhibitor partially blocked the effects of H(2)O(2) on up-regulation of Bcl-2 and Bcl-X(L) protein expression, down-regulation of Bax protein expression, and phosphorylation of Bcl-2 and IkappaBalpha. This investigation demonstrated for the first time that low concentrations of H(2)O(2) provide protection against the in vivo of As(2)O(3)-induced apoptosis. PI-3K plays a crucial role in enhancing cell survival during H(2)O(2), inhibiting As(2)O(3)-induced apoptosis in the Burkitt's lymphoma cells. As(2)O(3)-induced cancer cell apoptosis may be enhanced by certain antioxidants in the treatment protocol.     

Expression and cellular distribution of alpha(v)integrins in beta(1)integrin-deficient embryonic stem cell-derived cardiac cells

beta(1)integrin-deficient (beta(1)-/-) ES cells showed increased differentiation of cardiac cells characterized by reduced adhesion and high beating frequency. Whereas in whole embryoid body outgrowths of beta(1)-/- cells maximum levels of alpha(v), beta(3)and beta(5)integrin mRNA were delayed and transiently upregulated, in cardiac clusters isolated from beta(1)-/- cells, only beta(3)integrin mRNA levels were enhanced in comparison to wild-type (wt) cells. To answer the question, whether alpha(v)and beta(3)integrins may compensate, at least partially, the loss of beta(1)integrin function during cardiac differentiation, the distribution of alpha(v)and beta(3)integrins in beta(1)-/- and wt pacemaker-like cardiac cells was analyzed. A different distribution of alpha(v)and beta(3)integrins in beta(1)-/- v wt cardiac cells was found. In wt cardiac cells, beta(1)integrin was localized in specialized subsarcolemmal regions, in particular, at focal contacts and costameres, but alpha(v)integrin was diffusely distributed. In contrast, in beta(1)-/- cardiac cells, alpha(v)integrin was preponderantly localized at cell membranes, focal contacts and costameres. beta(3)integrin displayed a diffuse pattern both in wt and in beta(1)-/- pacemaker-like cells at early differentiation stages, whereas at terminal stages, beta(3)was colocalized with sarcomeres in wt, but not in beta(1)-/- pacemaker-like cells. Quantitative immunofluorescence analysis revealed increased alpha(v)and beta(3)integrin levels in beta(1)-/- pacemaker-like cardiac cells. Our results led us to conclude that altered cellular distribution of alpha(v)integrin and upregulation of beta(3)integrin correlate with growth and survival of beta(1)-/- cardiac pacemaker-like cells at an early developmental state. However, alpha(v)and beta(3)integrins cannot functionally compensate the loss of beta(1)integrin during terminal differentiation of cardiac cells implicating that cardiomyocytes require specific beta(1)integrin functions for cardiac specialization.     

Antagonistic effects of 24R,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 on L-type Ca2+ channels and Na+/Ca2+ exchange in enterocytes from Atlantic cod (Gadus morhua)

There is mounting evidence that vitamin D and its metabolites play important roles in regulating plasma calcium concentrations in teleost fish as in other vertebrates. The aims of the present study were to elucidate the possible cellular target mechanisms for the rapid actions of 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in Atlantic cod enterocytes at physiological doses, and to establish the concentration and thus the physiological range of circulating 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in the Atlantic cod. The plasma concentrations of 25(OH)D(3), 1,25(OH)(2)D(3) and 24R,25(OH)(2)D(3) were 15.3 +/- 2.7nM, 125.1 +/- 12.3pM and 10.1 +/- 23.5nM respectively. Exposure of enterocytes to 10mM calcium (Ca(2+)) evoked an increase in intracellular Ca(2+) concentrations ([Ca(2+)](i)). This increase was suppressed by 24R,25(OH)(2)D(3) dose-dependently, with an EC(50) of 4.9nM and a maximal inhibition of 60%. 24R,25(OH)(2)D(3) (20nM) abolished an increase in [Ca(2+)](i) (approximately 252%) in the control enterocytes exposed to 10microM S(-)-BAYK-8644, suggesting that the hormone acts by inhibiting Ca(2+) entry through L-type voltage-gated Ca(2+) channels. Administration of 20nM 24R,25(OH)(2)D(3) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 20%, indicating a release of Ca(2+) from intracellular stores. Administration of 25(OH)D(3) (20nM) resulted in a biphasic change in the enterocyte [Ca(2+)](i): within 1--5s, it decreased to 87 +/- 12nM below its mean basal [Ca(2+)](i) (334 +/- 13nM), followed by a rapid recovery of [Ca(2+)](i) to a new level, 10% lower than the initial [Ca(2+)](i). The rapid decrease, the recovery rate and the final [Ca(2+)](i) were all affected dose-dependently by 25(OH)D(3), with EC(50) values of 8.5, 17.0 and 18.9nM respectively. Furthermore, the effects of 25(OH)D(3) were sensitive to sodium (Na(+)), bepridil (10microM) and nifedipine (5 microM), suggesting that 25(OH)D(3) regulates the activity of both basolateral membrane-associated Na(+)/Ca(2+) exchangers and brush border membrane-associated L-type Ca(2+) channels. Administration of 25(OH)D(3) (10nM) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 18%, indicating a release of Ca(2+) from intracellular stores. 1,25(OH)(2)D(3) also affected enterocyte [Ca(2+)](i) in a biphasic manner: the rapid decrease, the recovery rate, and the mean final [Ca(2+)](i) were all affected dose-dependently, with EC(50) values of 8.3, 24.5 and 7.7nM respectively. The high EC(50) values for 1,25(OH)(2)D(3) compared with circulating concentrations of 1,25(OH)(2)D(3) (130pM) suggest that this effect is pharmacological, rather than of physiological relevance in enterocyte Ca(2+) homeostasis of the Atlantic cod. It is concluded that 24R,25(OH)(2)D(3) has a physiological role in decreasing intestinal Ca(2+) uptake via inactivation of L-type Ca(2+) channels, whereas the physiological role of 25(OH)D(3) is to increase enterocyte Ca(2+) transport via activation of Na(+)/Ca(2+) exchangers, concurrent with activation of L-type Ca(2+) channels.     

Dopamine D1 and adenosine A1 receptors form functionally interacting heteromeric complexes

The possible molecular basis for the previously described antagonistic interactions between adenosine A(1) receptors (A(1)R) and dopamine D(1) receptors (D(1)R) in the brain have been studied in mouse fibroblast Ltk(-) cells cotransfected with human A(1)R and D(1)R cDNAs or with human A(1)R and dopamine D(2) receptor (long-form) (D(2)R) cDNAs and in cortical neurons in culture. A(1)R and D(1)R, but not A(1)R and D(2)R, were found to coimmunoprecipitate in cotransfected fibroblasts. This selective A(1)R/D(1)R heteromerization disappeared after pretreatment with the D(1)R agonist, but not after combined pretreatment with D(1)R and A(1)R agonists. A high degree of A(1)R and D(1)R colocalization, demonstrated in double immunofluorescence experiments with confocal laser microscopy, was found in both cotransfected fibroblast cells and cortical neurons in culture. On the other hand, a low degree of A(1)R and D(2)R colocalization was observed in cotransfected fibroblasts. Pretreatment with the A(1)R agonist caused coclustering (coaggregation) of A(1)R and D(1)R, which was blocked by combined pretreatment with the D(1)R and A(1)R agonists in both fibroblast cells and in cortical neurons in culture. Combined pretreatment with D(1)R and A(1)R agonists, but not with either one alone, substantially reduced the D(1)R agonist-induced accumulation of cAMP. The A(1)R/D(1)R heteromerization may be one molecular basis for the demonstrated antagonistic modulation of A(1)R of D(1)R receptor signaling in the brain. The persistence of A(1)R/D(1)R heteromerization seems to be essential for the blockade of A(1)R agonist-induced A(1)R/D(1)R coclustering and for the desensitization of the D(1)R agonist-induced cAMP accumulation seen on combined pretreatment with D(1)R and A(1)R agonists, which indicates a potential role of A(1)R/D(1)R heteromers also in desensitization mechanisms and receptor trafficking.     

Role of angiotensin II type 2 receptors and kinins in the cardioprotective effect of angiotensin II type 1 receptor antagonists in rats with heart failure

OBJECTIVES: We studied the role of angiotensin II type 2 (AT(2)) receptors and kinins in the cardioprotective effect of angiotensin II type 1 antagonists (AT(1)-ant) in rats with heart failure (HF) after myocardial infarction. BACKGROUND: The AT(1)-ant is as effective as angiotensin-converting enzyme inhibitors in treating HF, but the mechanisms whereby AT(1)-ant exert their benefits on HF in vivo are more complex than previously understood. METHODS: Brown Norway Katholiek rats (BNK), which are deficient in kinins because of a mutation in the kininogen gene, and their wild-type control (Brown Norway [BN]) underwent myocardial infarction. Two months later, they were treated for two months with: 1) vehicle; 2) AT(1)-ant (L158809, Merck, Rahway, New Jersey); 3) AT(1)-ant + AT(2)-ant (PD-123319, Parke Davis, Ann Arbor, Michigan); or 4) AT(1)-ant + kinin B(2) receptor antagonist (B(2)-ant) (icatibant) (only BN). We measured left ventricular weight (LVW) gravimetrically, myocyte cross-sectional area (MCSA) and interstitial collagen fraction (ICF) histologically, and ejection fraction by ventriculography. RESULTS: Development of HF was comparable in BN and BNK rats. The AT(1)-ant reduced LVW and MCSA and the AT(2)-ant blocked these effects in BN rats, but the B(2)-ant did not. The AT(1)-ant reduced LVW and MCSA in BNK rats, and this effect was reversed by the AT(2)-ant. In BN rats, ICF was reduced and LVEF increased by AT(1)-ant, and both AT(2)-ant and B(2)-ant reversed these effects. In BNK rats, the AT(1)-ant failed to reduce ICF, and its therapeutic effect on LVEF was significantly blunted. CONCLUSIONS: In HF, the AT(2) receptor plays an important role in the therapeutic effects of AT(1)-ant, and this effect may be mediated partly through kinins; however, kinins appear to play a lesser role in the antihypertrophic effect of AT(1)-ant.     

Effect of airway inflation pressure on forced expiratory maneuvers from raised lung volume in infants.

The raised lung volume technique is increasingly used to measure forced expiratory maneuvers in infants. However, there is no consensus regarding the optimal airway inflation pressure (P(inf)) required for such maneuvers, or the influence of small changes in P(inf) within and between infants. The aim of this study was to assess the effect of small differences (0.2-0.3 kPa) in P(inf) on forced vital capacity (FVC), forced expired volume in 0.5 sec (FEV(0.5)), and forced expired flow at 75% of vital capacity (FEF(75)), all derived from the raised volume rapid thoraco-abdominal compression (RVRTC) technique. Randomized paired forced expiratory maneuvers were obtained in 32 healthy infants ( 3.9-39.3 weeks old, 3.8-9.9 kg) with the safety pressure relief valve for P(inf) set to 2.7 kPa or 3.0 kPa (27 or 30 cm H(2)0). When mean (SD) P(inf) was increased by 8.4 (2.8)%, there was a significant (P < 0.01) increase in mean (SD) FVC, FEV(0.5), and FEF(75) by 5.8 (5.7)%, 6.1 (6)%, and 8.3 (16.2)%, respectively. In conclusion, relatively small differences in P(inf) will result in significant differences in FVC, FEV(0.5), and FEF(75) by RVRTC technique. Precision in setting and reporting the applied P(inf) is therefore essential, particularly if data are to be compared between centers.     

Hypoxia and reoxygenation increase H2O2 production in rats

To test the effect of transition from sustained hypoxia to normoxia on production of reactive oxygen species (ROS) in lungs, the authors measured hydrogen peroxide (H(2)O(2)) output in the expired air of rats breathing hypoxic, normoxic, and hyperoxic gas mixtures at the end of exposure to 72 hours of hypoxia. Twenty-one male Wistar rats (200 to 280 g) were randomly assigned to 1 of 3 groups. First two groups (experimental) were kept for 3 days in normobaric hypoxic chamber (F(1)O(2) 0.1), rats of the third group (controls) breathed air. The rats were then anesthetized, intubated, placed in the plethysmograph, and their ventilation measured. Two periods of exhaled breath condensate (EBC) collection, each lasting 1 hour, were then performed to assay H(2)O(2) output. The controls breathed during both samplings air, the first experimental group breathed during first sampling period hypoxic mixture (F(1)O(2) 0.1; SH-H measurement) and then, during second period, air (SH-H-A measurement), the second experimental group breathed first air (SH-A measurement) and then hyperoxic mixture (F(1)O(2) 1.0; SH-A-O(2) measurement). Concentration of H(2)O(2) in the EBC was assayed by chemiluminescence. H(2)O(2) production in the control group was low and similar in both measurements (20+/-10 and 13+/-5 pmol/h, mean+/-SEM). Exposure to 72 hours of hypoxia increased the H(2)O(2) production to 105+/-18 pmol/h (SH-H). Transition from hypoxia to normoxia resulted in an increase in the H(2)O(2) production (SH-A 421+/-24 pmol/h, and SH-H-A 366+/-19 pmol/h). Following transition from air breathing to hyperoxia did not affect the H(2)O(2) production (SH-A-O(2) 373+/-25 pmol/h). The results showed that sustained hypoxia and transition from sustained hypoxia to normoxia increased H(2)O(2) formation in the lungs.     

Microbiological results of bronchoalveolar lavage that was performed for opportunistic pulmonary infections

Between 2001-2002; in 62 cases, 33 (53%) male, 29 (47%) female, mean age 51.4 +/- 18.1 years) bronchoalveolar lavage (BAL) was performed for diagnosis of opportunistic pulmonary infection and specimens were evaluated for results of microbiological examinations. There was hematological malignancy in 18 (29%) and solid organ malignancy in 13 (21%) cases. Thirty-one (50%) cases were immunocompromised for reasons other than malignancy. By endoscopic evaluation endobronchial lesion was seen in 2 (3%) cases, indirect tumor signs were seen in 2 (3%) cases and signs of infection were seen in 11 (18%) cases. Forty-even (76%) cases were endoscopically normal. Acid-fast bacilli (AFB) direct examination was positive in 3 (5%) cases. In 4 (6%) cases mycobacterial culture was positive, Mycobacterium tuberculosis-polymerase chain reaction (PCR) was also positive in these four cases. Examination of gram-stained smears for bacteria was associated with infection in 14 (23%) cases. Bacteriologic cultures were positive for single potential pathogen in 10 (16%) cases, and for mixed pathogens in 7 (11%) cases for a total number of 17 (27%). Fungal cultures were positive in 3 (5%) cases all of which had hematological malignancy. As a result in 24 (39%) cases microbiological agent of infection is determined: in four mycobacteria, in 17 bacteria other than mycobacteria and in three fungi.     

Thyroxine plus low-dose, slow-release triiodothyronine replacement in hypothyroidism: proof of principle.

Studies in hypothyroid rats show that, when infused with a combination of thyroxine (T4) plus triiodothyronine (T3) to normalize thyrotropin (TSH), euthyroidism in all organs is only ensured when T(4) and T(3) are administered in a ratio as normally secreted by the rat thyroid. As substitution with T(4)-only results in an abnormal serum T(4)/T(3) ratio, it is also possible that in humans, euthyroidism does not exist at the tissue level in many organs, considering that iodothyronine metabolism in the human and the rat share many similar mechanisms. Recent reports in which cognitive function and well-being are compared in patients with primary hypothyroidism substituted with T(4)-only versus substitution with T(4) plus T(3) result in controversial findings in that either positive or no effects were found. In all these studies T(3) was used in the plain form that results in nonphysiologic serum T(3) peaks. In these studies it is suggested that substitution with T(3 )should preferably be performed with a preparation that slowly releases T(3) to avoid these peaks. In the study reported here we show that treatment of hypothyroid subjects with a combination of T(4) plus slow-release T(3) leads to a considerable improvement of serum T(4) and T(3) values, the T(4)/T(3) ratio and serum TSH as compared to treatment with T(4)- only. Serum T(3) administration with slow-release T(3) did not show serum peaks, in contrast to plain T(3).     

The role of copper and protons in heme-copper oxidases: kinetic study of an engineered heme-copper center in myoglobin

To probe the role of copper and protons in heme-copper oxidase (HCO), we have performed kinetic studies on an engineered heme-copper center in sperm whale myoglobin (Leu-29 --> HisPhe-43 --> His, called Cu(B)Mb) that closely mimics the heme-copper center in HCO. In the absence of metal ions, the engineered Cu(B) center in Cu(B)Mb decreases the O(2) binding affinity of the heme. However, addition of Ag(I), a redox-inactive mimic of Cu(I), increases the O(2)-binding affinity. More importantly, copper ion in the Cu(B) center is essential for O(2) reduction, as no O(2) reduction can be observed in copper-free, Zn(II), or Ag(I) derivatives of Cu(B)Mb. Instead of producing a ferryl-heme as in HCO, the Cu(B)Mb generates verdoheme because the engineered Cu(B)Mb may lack a hydrogen bonding network that delivers protons to promote the heterolytic OO cleavage necessary for the formation of ferryl-heme. Reaction of oxidized Cu(B)Mb with H(2)O(2), a species equivalent in oxidation state to 2e(-), reduced O(2) but, possessing the extra protons, resulted in ferryl-heme formation, as in HCO. The results showed that the Cu(B) center plays a critical role in O(2) binding and reduction, and that proton delivery during the O(2) reduction is important to avoid heme degradation and to promote the HCO reaction.     

Pharmacokinetics of traditional Chinese syndrome and recipe: a hypothesis and its verification (I)

AIM:To propose a hypothesis defining the absorption, distribution, metabolism and elimination of traditional Chinese recipe (TCR)component in blood of healthy subjects and patients, and estimate its correctness.METHODS:The pharmacokinetics (PK) of same dose of drug was studied in the animal model of traditional Chinese syndrome (S)and healthy animals. The classification, termi-nology, concept and significance of the hypothesis were set forth with evidence provided in the present study. The hypotheses consisted of traditional Chinese syndrome PK (S-PK) and traditional Chinese recipe PK (R-PK). Firstly, the observed tetramethylpyrazine (TMP) PK in healthy, chronically reserpinized rats (rat model of spleen deficiency syndrome, RMSDS) and RMSDS treated with Sijunzi decoction (SJZD) for confirmation were used to verify S-PK; secondly, the ferulic acid (FA) PK in healthy and high molecular weight dextran (HMWD)-induced rabbit model with blood stasis syndrome (RDBSS) was also used to verify S-PK; and lastly, TMP PK parameters in serum of healthy rats after orally taken Ligusticum wallichii (LW), LW and Salvia miltiorrhiza (LW&SM) decoctions were compared to verify R-PK.RESULTS:The apparent first-order absorption Ka,(13.61 plus minus 2.56)h(-1) ,area under the blood drug concentration-time curve AUC, (24.88 plus minus 9.76)&mgr;gcenter doth(-1)mL(-1) , maximum drug concentration C(max), (4.82 plus minus 1.23)&mgr;gcenter dotmL(-1) of serum TMP in RMSDS were increased markedly(P< 0.05) compared with those Ka = (5.41 plus minus1.91)h(-1), AUC = (5.20 plus minus 2.57)&mgr;gcenter doth(-1)center dotmL(-1), C(max) = (2.33 plus minus 1.77)&mgr;gcenter dotmL(-1) of healthy rats (HR). The apparent first-order rate constant for alpha and beta distribution phase alpha = (0.38 plus minus 0.09)h(-1), beta = (0.06 plus minus 0.03)h(-1) , the apparent first-order intercompartmental transfer rate constants K10 = (0.24 plus minus 0.07)h(-1), K(12) = (0.11 plus minus 0.02)h(-1), K(21) = (0.11 plus minus 0.02)h(-1) of serum TMP in RMSDS were decreased significantly (P <0.01) compared with those K(10) = (0.88 plus minus 0.20)h(-1), K(12) = (1.45 plus minus 0.47)h(-1), K(21) = (0.72 plus minus 0.22)h(-1) of HR. However, no apparent differences occurred between HR and RMSDS treated with SJZD. The serum FA concentration and its AUC (5.6690 plus minus 2.3541)&mgr;gcenter doth(-1)center dotmL(-1) in RMBSS were also higher than those AUC =(2.7566 plus minus0.8232)&mgr;gcenter doth(-1)center dotmL(-1) of healthy rabbits (P <0.05). The Ka (11.51 plus minus 2.82)h(-1), AUC (0.84 plus minus0.17)&mgr;gcenter doth(-1)center dotmL(-1) of LW & SM-derived TMP in serum were much lower (P <0.05) than those Ka = (19.58 plus minus 4.14)h(-1),AUC = (1.27 plus minus 0.26)&mgr;gcenter doth(-1)center dotmL(-1) of LW-derived TMP in serum after oral decoctions.CONCLUSION:The SDS and blood stasis syndrome state could affect significantly the pharmacokinetic parameters of drugs and the abnormal SDS pharmacokinetic parameters could be normalized by SJZD. The combination of Chinese medicine in TCR could reciprocally affect the pharmacokinetic parameters of other components absorbed into the systemic circulation. These results support the S and R-PK hypothesis.     

D3 dopamine receptor regulation of D5 receptor expression and function in renal proximal tubule cells

Dopamine receptor, via D(1)-like and D(2)-like receptors, increases sodium excretion in kidney. We have reported positive interactions between D(3) and D(1) receptors in renal proximal tubule (RPT) cells. These reports, however do not preclude that there may be also interaction between D(3) and D(5) receptors, because of the lack of selective D(1) and D(5) receptor agonists or antagonists. We hypothesize that D(3) receptors can regulate D(5) receptors, and that D(3) receptor regulation of D(5) receptors in RPTs is impaired in spontaneously hypertensive rats (SHRs). It showed that a D(3) receptor agonist, PD128907, by the activation of protein kinase C activity, increased the expression of D(5) receptors in a concentration- and time-dependent manner in RPT cells from Wistar-Kyoto (WKY) rats. The stimulatory effect of the D(3) receptor on D(5) receptor expression was impaired in RPT cells from SHRs. The effect of D(3) receptor on D(5) receptor is functionally relevant; stimulation of D(5) receptor decreases Na(+)-K(+) adenosine triphosphatase (ATPase) activity in WKY cells. Pretreatment with D(3) receptor agonist for 24 h enhances the D(5) receptor expression and D(5) receptor-mediated inhibitory effect on Na(+)-K(+) ATPase activity in WKY cells, but decreases them in SHR cells. The effect of D(3) receptor on D(5) receptor expression and function was also confirmed in the D(5) receptor-transfected HEK293 cells. It indicates that activation of D(3) receptor increases D(5) receptor expression and function. Altered regulation of D(3) receptor on D(5) receptors may have a role in the pathogenesis of hypertension.     

Time of day for exercise on blood pressure reduction in dipping and nondipping hypertension

Time of day (TOD) for exercise may influence blood pressure (BP) reduction in hypertension because of the diurnal variation of BP and the duration of BP reduction following a single bout of exercise. The purpose of this study was to observe the effects of TOD for exercise on ambulatory blood pressure reduction in dipping (n=5) and nondipping (n=9) hypertension (<10% drop in nighttime BP (BP(night))). HYPOTHESES: (1) evening exercise (PM(ex)) would exhibit a greater BP(night) reduction in Non-Dippers than Dippers, (2) morning exercise (AM(ex)) would exhibit similar daytime BP (BP(day)) reduction in Dippers and Non-Dippers, (3) AM(ex) would exhibit greater 24 h BP (BP(24 h)) reduction than PM(ex) in Dippers, and (4) AM(ex) and PM(ex) would exhibit similar BP(24 h) reduction in Non-Dippers. BP responses to AM(ex) (0600-0800 h; 30 min at 50% VO(2peak)) and PM(ex) (1700-1900 h) were compared to each control day in a randomized design. Systolic (S) and diastolic (D) BP were averaged for BP(24 h), BP(day), and BP(night). A two-way ANOVA (dipping X time of exercise) using BP reduction with repeated measures were performed at P<0.05. FINDINGS: (1) Non-Dippers respond to exercise despite of TOD for exercise, (2) PM(ex) exhibited a greater SBP(night) reduction in Non-Dippers than Dippers, (3) AM(ex) exhibited similar SBP(day) reductions in Dippers and Non-Dippers, and (4) AM(ex) and PM(ex) exhibited similar SBP(24 h) reduction in Dippers and Non-Dippers. Dippers and Non-Dippers respond differently to TOD for exercise. The duration of the BP reduction persists up to 24 h after exercise.     

转化生长因子β1与诱导型一氧化氮合酶相互调控对大鼠低氧性肺动脉高压的作用

目的观察转化生长因子β1(TGF-β1)与诱导型一氧化氮合酶(iNOS)基因在低氧性肺动脉高压(HPH)大鼠肺动脉的动态表达变化.方法 40只成年雄性Wistar大鼠随机分成对照组(C组)、缺氧3、7、14和21 d组(H3、H7、H14和H21组),每组8只,测各组大鼠平均肺动脉压(mPAP)、血管形态学指标、右室肥大指数(RVHI);原位杂交和免疫组化检测TGF-β1、iNOS基因表达.结果 H7组大鼠mPAP[(18.41±0.37)mm Hg,1 mm Hg=0.133 kPa]显著高于C组(P<0.05),H14组达高峰[(21.17±0.23)mm Hg]并维持于高水平.肺血管重塑、右心室肥大缺氧14 d后出现.C组大鼠肺动脉中膜iNOS蛋白弱阳性(0.109±0.021),H3组增高(0.225±0.030,P<0.01),H7组(0.312±0.036)稳定于高水平.C组大鼠肺动脉壁iNOS mRNA弱阳性(0.112±0.030),H3组表达增强(0.245±0.036),H7组达高峰(0.318±0.034,P<0.01)并维持于高水平.TGF-β1蛋白在C组呈弱阳性(0.042±0.012),H3组表达增强(0.198±0.031),H7组达高峰(0.267±0.035,P<0.01),随着缺氧时间延长,TGF-β1逐渐向基线水平回降;C组TGF-β1 mRNA呈弱阳性表达(0.145±0.018),H3、H7组表达增高不明显(0.163±0.021、0.176±0.026),H14组增高(0.385±0.028,P<0.01),并维持于高水平,TGF-β1 mRNA、蛋白于肺动脉中膜和外膜表达.相关分析表明,TGF-β1、iNOS均与mPAP和血管重塑呈正相关(r=0.843～0.937,P均＜0.01);TGF-β1蛋白(外膜)与iNOS mRNA、蛋白均呈负相关(r分别为-0.856、-0.835,P均＜0.01).结论 TGF-β1和iNOS均参与大鼠HPH的发病,iNOS可能通过NO上调TGF-β1表达,TGF-β1可能通过降低mRNA的稳定性、减慢翻译速率和加快酶蛋白降解抑制iNOS表达.     

三氧化二砷洗脱支架防治兔血管损伤后再狭窄的实验研究

目的冠状动脉支架内再狭窄主要是由血管损伤后内膜增生引起,研究三氧化二砷(As2O3)多聚左旋乳糖酸(PLLA)涂层的药物洗脱支架在兔的损伤髂动脉内抑制内膜增生防治再狭窄的疗效、机制及As2O3释放的药物代谢动力学。方法45只雄性新西兰白兔,随机分三组,每组15只,分别将裸支架、PLLA涂层支架、As2O3洗脱支架置入兔髂动脉的近端,饲养28d后处死,组织病理学检测内膜厚度,TUNEL法测细胞凋亡。在体药代动力学研究:雄性新西兰白兔48只,按支架置入后饲养时间(2h、1d、3d、7d、14d、28d)分为6组,每组8只,检测血浆中及支架处组织中的As2O3浓度。结果As2O3洗脱支架释放As2O3达28d,第一天支架处组织中的As2O3浓度约是血浆中的55000倍,14d约为22000倍。As2O3洗脱支架较PLLA支架和裸支架分别减少内膜增生51%、31%。As2O3洗脱支架组较PLLA支架组和裸支架组血管平滑肌细胞凋亡面积明显增加(21·0±3·3比6·2±1·9,5·3±2·1)。结论As2O3洗脱支架在局部血管处释放As2O3达28d,在兔的髂动脉可有效抑制由支架和球囊损伤导致的兔血管内膜增生,其机制之一是促进平滑肌细胞凋亡。     

Association between transforming growth factor-beta and hypertension

Discordant findings are reported on the left ventricular transforming growth factor-beta(1) (TGF-beta(1)) mRNA levels in various rat models. Left ventricular TGF-beta(1) mRNA levels did not differ between spontaneously hypertensive rats (SHR) and normal rats, between deoxycorticosterone (DOCA)-salt and sham-operated hypertensive rats, but were increased in stroke-prone spontaneously hypertensive rats (SHRSP) and in post-myocardial infarction (MI) rats. Renal cortical TGF-beta(1) mRNA levels were, however, higher in DOCA-salt hypertensive rats. Angiotensin II subtype 1 receptor antagonism (AT(1)R) and angiotensin converting enzyme inhibition (ACEI) decreased left ventricular and vascular smooth muscle TGF-beta(1) mRNA levels in SHR and renal TGF-beta(1) mRNA in DOCA-salt hypertensive rats and in SHRSP. In post-MI rats ventricular TGF-beta(1) mRNA decreased by AT(1)R antagonism. In essential hypertensive patients, TGF-beta(1) protein as well as TGF-beta(1) mRNA levels are hyperexpressed. The TGF-beta(1) overproduction in hypertension can be attributed to various factors such as elevated angiotensin II, increased systemic blood pressure (BP) per se, increased fluid shear stress and a differential expression of TGF-beta(1) linked to DNA polymorphism in the promoter. The Arg(25) polymorphism in the TGF-beta(1) gene is associated with higher BP. A higher plasma TGF-beta(1) concentration is found in hypertensive patients with microalbuminuria and left ventricle hypertrophy. In these patients, AT(1)R antagonism and ACEI reduced these plasma TGF-beta(1) levels significantly.     

Amount of H antigen expressed on circulating von Willebrand factor is modified by ABO blood group genotype and is a major determinant of plasma von Willebrand factor antigen levels

To investigate whether the effect of ABO blood group on plasma von Willebrand factor (vWF) levels is mediated by the ABH antigenic determinants carried on N-linked glycans of vWF, we studied 158 group A and group O healthy volunteers. vWF antigen (vWF:Ag) and factor VIII antigen (FVIII:Ag) levels were highest in A(1)A(1) individuals and higher in A(1)O(1) than in A(2)O(1) or O(1)O(1) individuals. Plasma A transferase activity and the amount of A antigen expressed per unit vWF (AvWF) were significantly higher in A(1)A(1) than in A(1)O(1) individuals and higher in A(1)O(1) than in A(2)O(1) individuals. AvWF was correlated strongly with plasma levels of A transferase activity. Thus, we have clearly demonstrated a direct relationship between ABO genotype, A transferase expression, and the amount of A antigen expressed on circulating vWF. H antigen expression per unit vWF (HvWF) was highest in group O individuals. Among group A individuals, the pattern of HvWF expression was A(2)O(1)>A(1)O(1)>A(1)A(1). In group O and group A(2)O(1) individuals, HvWF was inversely correlated with plasma vWF levels. In contrast, among group A(1)A(1) and A(1)O(1) individuals, there was no relationship between AvWF and plasma vWF levels. These findings suggest that it is H antigen expression that mediates the ABO effect on plasma vWF concentration.