Abstract P6-06-04: Targeting replication stress in triple negative breast cancer treatment regimen: An emerging approach

Triple-negative breast cancers (TNBCs) represent aggressive heterogeneous subtype of breast cancer with poor clinical outcome. TNBCs have been reported to have high levels of replication stress due to i) various oncogene activations (C-myc or EGFR) ii) germline BRCA mutations iii) “BRCAness” in the absence of BRCA mutations in sporadic TNBCs. Replication stress is known to cause genomic instability, promote tumorigenesis and plays a critical role in therapy resistance in TNBCs. Therefore, targeting replication stress has emerged as an effective approach for better TNBC treatment through further downregulation of the remaining checkpoints to induce catastrophic failure of TNBC cells proliferation. Herein, we evaluated the anticancer efficacy of Carbazole Blue (CB), a synthetic analogue of Carbazole, on TNBC cells growth and progression. Our results demonstrated that CB inhibits short and long term viability of TNBC (MDA-MB-231, MDA-MB-468 and BT549) cells in a dose dependent manner without affecting normal mammary epithelial (MCF-10A) cells. In addition, CB treatment significantly reduced proliferation of TNBC cells, as evidenced by the BrdU proliferation assay. Consistent with this, our results further demonstrated that CB treatment induced G1/S cell cycle arrest and apoptosis in TNBCs. Importantly, systemic delivery of CB using nanoparticle-based delivery approach suppressed breast cancer growth without inducing toxicity, in preclinical orthotopic xenograft and PDX mouse models of TNBC. Furthermore, our gene microarray analysis revealed that CB treatment modulates the expression and activity of several genes known to be involved in DNA replication (CDC6, CDT1, MCMs, Claspin, POLE and PCNA) and associated DNA repair machinery such as (XRCC3, Exo1 and RAD51), which play pivotal roles in replication stress. Our results for the first time highlight the potential use of CB as a novel and potent therapeutic agent for treating TNBCs. As exploiting replication stress to treat cancer is gaining major interest, compound/s that may induce replication stress and inhibit DNA repair ability of cancer cells, has immense translational potential.

Citation Format: Rajamanickam S, Park JH, Bates K, Timilsina S, Eedunuri VK, Onyeagucha B, Subbarayalu P, Abdelfattah N, Jung KH, Favours E, Mohammad TA, Chen H-IH, Vadlamudi RK, Chen Y, Kaipparettu BA, Arbiser JL, Rao MK. Targeting replication stress in triple negative breast cancer treatment regimen: An emerging approach [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-06-04.

Sonographic demonstration of human small intestinal migrating motor complex phase III

BACKGROUND

Migrating motor complex phase III (MMC phase III) of intestine is an important physiological mechanism traditionally recognized by myoelectric recordings or pressure tracings. Direct imaging is difficult and sonographic visualization in human has not been reported.

METHODS

We have demonstrated this unique phenomenon in three patients who underwent abdominal sonographic examinations. Characteristic images were recorded by videotape and both spatial and temporal features were analyzed.

KEY RESULTS

Occurrences of multiple equally spaced, rhythmic intestinal contractions were observed. Parameters including wave frequency, propagation velocity, and duration of the events agreed with those of the well-known phase III. The presence of distinct cyclic patterns observed in two and abolition by meal in the other patient further support our conclusion.

CONCLUSIONS & INFERENCES

We conclude that the migrating waves observed in our study represent the human MMC phase III. This unique finding in human subjects merits further investigation.

Nicotinamide abrogates acute lung injury caused by ischaemia/reperfusion

Poly (ADP-ribose) synthase or polymerase (PARS and PARP, respectively) is a cytotoxic enzyme which causes cellular damage. Nicotinamide, a compound of vitamin B complex, has been reported to exert an inhibitory effect on PARS or PARP. The present study tests the effects of nicotinamide on acute lung injury and associated alterations following ischaemia/reperfusion (I/R) of the isolated perfused rat's lung. I/R increased the lung weight (LW) to body weight ratio, LW gain, protein and dye tracer leakage, pulmonary arterial pressure and capillary permeability. The insult also increased nitrate/nitrite, methyl guanidine, tumour necrosis factor-alpha and interleukin-1beta in lung perfusate, while it decreased adenosine triphosphate content with an increase in PARP activity in lung tissue. Most of the I/R-induced changes were abrogated by post-treatment (30 min after I/R) with nicotinamide (100 mg.kg(-1) body weight). However, the increase in pulmonary arterial pressure was enhanced by nicotinamide post-treatment. Following I/R, the inducible nitric oxide synthase (iNOS) mRNA expression was enhanced. Nicotinamide reduced the iNOS expression. The results suggest that nicotinamide exerted a protective effect on the acute lung injury caused by ischaemia/reperfusion. The mechanisms may be mediated through the inhibition on the poly (adenosine diphosphate-ribose) polymerase activity, inducible nitric oxide synthase expression and the subsequent suppression of nitric oxide, free radicals and pro-inflammatory cytokines with restoration of adenosine triphosphate.

Lack of a Protective Effect of Insulin on Three Reperfusion-Liver Injury Models in Rats and Mice

Our objective was to investigate the potential protective effects of insulin on the liver injury induced in three ischemia and reperfusion (I/R) models.

METHODS

Three I/R models were used: (1) I/R of the liver was produced in isolated, perfused rat livers; (2) in in situ I/R of the liver in rats, ischemia was induced by clamping off the hepatic artery and portal vein for 40 minutes, the flow then restored, and the liver reperfused for 90 minutes; (3) in in situ I/R of the liver in mice, ischemia was induced by clamping off the hepatic artery for 15 minutes, the flow then restored, and the liver reperfused for 45 minutes. In all three cases, blood samples collected before ischemia and after reperfusion were analyzed for sGOT. Plasma nitrate/nitrite, hydroxyl radicals, and tumor necrosis factor were also measured. In each model, a dose of insulin sufficient to induce euglycemia was administered to assess its protective effect on liver injury and inflammation.

RESULTS

These I/R protocols resulted in a significant increase in sGOT and in three inflammatory parameters; nitric oxide, hydroxyl radicals, and tumor necrosis factor. Pretreatment with insulin did not attenuate the liver injury in any of the three I/R models.

CONCLUSIONS

Although insulin has been reported to provide anti-inflammatory benefits by reducing oxidative and nitrosative stress and cytokine release, none of these protective effects was seen in the three I/R-induced liver injury models we tested.

Ischemia/Reperfusion-Induced Low Reactivity of the Rat Superior Mesenteric Vascular Bed is Associated With Expression of Nitric Oxide Synthases

Our objective was to investigate the mRNA and protein expressions of eNOS and iNOS in the mesenteric vascular bed after ischemia and reperfusion of the rat superior mesenteric artery (SMA) and the role of nitric oxide (NO) in the response of the vascular bed to vasoconstrictors following reperfusion of the SMA.

METHODS

Real-time polymerase chain reaction and immunohistochemistry were used to monitor the mRNA and protein expression of eNOS and iNOS after I/R challenge to the rat SMA. Ischemia was induced by clamping the SMA for 40 minutes, after which the flow was restored and the vessels were reperfused for 300 minutes. Blood samples were collected for assays of lactic dehydrogenase, tumor necrosis factor (TNF), hydroxyl radical, and NO. After ischemia/reperfusion, the vascular beds were separated for analysis of the expression of eNOS and iNOS. The SMA with its associated intestinal tissue was isolated and perfused in vitro with Tyrode's solution (N = 8) then challenged with phenylephrine.

RESULTS

Reperfusion of the SMA induced an increase in blood concentrations of lactic dehydrogenase (P < .001; N = 8), hydroxyl radical (P < .05), TNF (P < .001), and NO (P < .05). ENOS and iNOS mRNA expression increased 1.3 +/- 0.1-fold and 19.6 +/- 3.5-fold, respectively when compared to the sham-operated group. Protein expression increased 1.9 +/- 0.4-fold and 12.6 +/- 3.1-fold, respectively, after reperfusion (N = 3) when compared with sham-treated rats. In vitro challenge showed that administration of phenylephrine (10(-8) approximately 10(-4) nmol) produced vasoconstriction in a dose-related manner. Maximum contractile responses to phenylephrine were attenuated in reperfused SMA. Addition of the NOS inhibitor N(G)-nitro-L-arginine (L-NNA, 10(-4) M) resulted in full recovery of the response to phenylephrine.

CONCLUSIONS

Ischemia/reperfusion of the SMA results in a decrease in vascular reactivity of the mesenteric vessels that is dependent on NOS expression by the intestinal vascular bed.

Oxygen radicals and matrix metalloproteinases mediate reperfusion liver injury

Many pathological processes involve the breakdown and remodeling of the extracellular matrix, which is mediated by the family of important enzymes known as matrix metalloproteinases (MMPs). One such process is warm ischemia/reperfusion (I/R) injury, the most important cause of dysfunction of liver allografts. We monitored protein expression of MMP-9 by Western blotting in rat liver after I/R. We also monitored changes in total MMP activity in the serum before and after I/R. Ischemia was induced by clamping the common hepatic artery and portal vein for 40 minutes and reperfusing for 90 minutes. Blood samples collected before ischemia and after reperfusion were analyzed for AST, hydroxyl radical, and tumor necrosis factor (TNFalpha). This protocol resulted in a high level of MMP-9 expression in liver tissue. Total MMP activity in serum was also significantly increased. Levels of AST, hydroxyl radicals, and TNF alpha were concomitantly increased. Ilomastat, an MMP inhibitor, attenuated the I/R-induced liver injury. After administration of the oxygen radical scavenger N-acetylcysteine (NAC), total MMP activity was suppressed, and liver injury was again attenuated. These results indicated that reperfusion liver injury induced an increase in MMP-9 protein expression and in serum MMP activity. The protective effects of an MMP inhibitor and NAC indicate that oxygen radical production is involved in MMP expression and liver injury associated with I/R.

Compulsive exercise acutely upregulates rat hippocampal brain-derived neurotrophic factor

This study was to examine the effects of treadmill exercise on the expression of brain-derived neurotrophic factor (BDNF) in rat hippocampus. After 1-wk treadmill familiarization, animals in exercise groups received a 4-wk exercise training or an acute exercise. They were sacrificed 2 h or 2 d after exercise and their hippocampal BDNF mRNA and protein levels were determined. We demonstrated that 1) hippocampal BDNF mRNA and protein levels were both elevated in response to exercise training at 2 h after the last run but not after 2 d; 2) an acute moderate exercise (1 or 3 d) increased BDNF protein levels; 3) acute severe exercise increased BDNF protein and mRNA levels in animals under a familiarization regimen, while suppressed the BDNF mRNA level in rats without treadmill familiarization, paralleling the stress effect of immobilization/water exposure. We conclude that compulsive treadmill exercise with pre-familiarization acutely upregulates rat hippocampal BDNF gene expression.

Aggressive angiomyxoma of the scrotum

Aggressive angiomyxoma is a rare and nonmetastasizing soft tissue tumor of the pelvis and perineum and occurs almost exclusively in adult females. It infiltrates locally and has a high risk of local recurrence. Recommended treatment of the symptomatic patient is wide excision with tumor-free margins and close postoperative monitoring. Herein, a case of aggressive angiomyxoma in an adult male is described, which arose in the scrotum over 12 months. The tumor showed an intermediate signal on T1-weighted MRI images. Contrast-enhanced T1-weighted images showed good enhancement. Wide excision of the tumor was performed. The surgical specimen measured 7 x 5 x 5 cm in size and weighed 80 g. The tumor's surface was smooth and had a gelatinous cut surface. Grossly, it was encapsulated with a pleura-like membrane and had a finger-like projection. Microscopically, sections showed many walled vessels of various sizes, collagen fibrils, a loose myxoid background. and spindle stroma cells. MRI and CT showed the angiomatous and myxomatous nature of the tumor wall. To the authors' knowledge, this is the first report to describe MRI findings in scrotal angiomyxoma.

The protective effect of niacinamide on ischemia-reperfusion-induced liver injury

Reperfusion of ischemic liver results in the generation of oxygen radicals, nitric oxide (NO) and their reaction product peroxynitrite, all of which may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose)synthase (PARS). This results in rapid depletion of intracellular nicotinamide adenine dinucleotide and adenosine 5'-triphosphate (ATP) and eventually induces irreversible cytotoxicity. In this study, we demonstrated that niacinamide, a PARS inhibitor, attenuated ischemia/reperfusion (I/R)-induced liver injury. Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 min. Thereafter, flow was restored and the liver was reperfused for 90 min. Blood samples collected prior to I and after R were analyzed for methyl guanidine (MG), NO, tumor necrosis factor (TNF-alpha) and ATP. Blood levels of aspartate transferase (AST), alanine transferase (ALT) and lactate dehydrogenase (LDH) which served as indexes of liver injury were measured. This protocol resulted in elevation of the blood NO level (p < 0.01). Inflammation was apparent, as TNF-alpha and MG levels were significantly increased (p < 0.05 and p < 0.001). AST, ALT and LDH were elevated 4- to 5-fold (p < 0.001), while ATP was significantly diminished (p < 0.01). After administration of niacinamide (10 mM), liver injury was significantly attenuated, while blood ATP content was reversed. In addition, MG, TNF-alpha and NO release was attenuated. These results indicate that niacinamide, presumably by acting with multiple functions, exerts potent anti-inflammatory effects in I/R-induced liver injury.

Hypotensive effects of captopril on physical properties of the arterial system in young and adult rats

We determined the acute effects of the angiotension converting enzyme inhibitor captopril on the arterial mechanics in rats at different ages, based on the exponentially tapered T-tube model. Male Wistar-Kyoto rats aged 4 and 12 months were individually referred to as young (n = 8) and adult rats (n = 8) and were anesthetized and thoractomized. The pulsatile aortic pressure and flow signals before and after the administration of captopril (20 mg/kg, i.p.) were measured by a high-fidelity pressure sensor and an electromagnetic flow probe, respectively. In each age group, captopril showed little change in basal heart rate as well as cardiac output. However, captopril produced a drop of 15% in mean aortic pressure in young and a fall of 12% in adult rats. In addition. captopril reduced total peripheral resistance by 21% in young and by 23% in adult animals. As for the pulsatile nature of the arterial system, captopril had increased wave transit time of the lower body circulation of 10% in young and of 12% in adult rats. By contrast, captopril reduced wave reflection factor by 22% in young and by 25% in adult animals. In conclusion, the converting enzyme inhibitor captopril has a stiffness-decreasing effect on Windkessel vessels and a dilated effect on resistance arterioles in either young or adult rats. No age dependence of vascular response and reflex tachycardia to captopril has been found in rats between 4 and 12 months.

The protective effect of niacinamide on ischemia-reperfusion-induced liver injury

Reperfusion of ischemic liver results in the generation of oxygen radicals, nitric oxide (NO) and their reaction product peroxynitrite, all of which may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose)synthase (PARS). This results in rapid depletion of intracellular nicotinamide adenine dinucleotide and adenosine 5'-triphosphate (ATP) and eventually induces irreversible cytotoxicity. In this study, we demonstrated that niacinamide, a PARS inhibitor, attenuated ischemia/reperfusion (I/R)-induced liver injury. Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 min. Thereafter, flow was restored and the liver was reperfused for 90 min. Blood samples collected prior to I and after R were analyzed for methyl guanidine (MG), NO, tumor necrosis factor (TNF-alpha) and ATP. Blood levels of aspartate transferase (AST), alanine transferase (ALT) and lactate dehydrogenase (LDH) which served as indexes of liver injury were measured. This protocol resulted in elevation of the blood NO level (p < 0.01). Inflammation was apparent, as TNF-alpha and MG levels were significantly increased (p < 0.05 and p < 0.001). AST, ALT and LDH were elevated 4- to 5-fold (p < 0.001), while ATP was significantly diminished (p < 0.01). After administration of niacinamide (10 mM), liver injury was significantly attenuated, while blood ATP content was reversed. In addition, MG, TNF-alpha and NO release was attenuated. These results indicate that niacinamide, presumably by acting with multiple functions, exerts potent anti-inflammatory effects in I/R-induced liver injury.

The expression of neuropeptides in hyperplastic and malignant prostate tissue and its possible clinical implications

PURPOSE

We characterized the incidence and pattern of distribution of neuroendocrine differentiated tumor cells in prostatic hyperplastic and carcinomatous tissue, correlated neuroendocrine differentiation with prostate specific antigen (PSA) and assessed whether neuroendocrine cells have value as an independent indicator of poor prognosis in patients with prostate carcinoma.

MATERIALS AND METHODS

We immunohistochemically evaluated hyperplastic and carcinomatous prostate specimens for chromogranin A, neuron specific enolase and serotonin expressing tumor cells. The expression of various markers in cells was analyzed and correlated with tumor DNA ploidy, disease grade and stage, PSA and clinical course in patients with prostate cancer.

RESULTS

Enrolled in our study were 31 patients with hyperplastic prostate tissue and 30 with prostatic carcinoma. Followup in cancer cases was 1 to 9 years (mean 3.7). During followup 9 patients (30%) died of cancer. We noted DNA content aneuploidy in 5 cases (16.7%) of prostate carcinoma. Chromogranin A, neuron specific enolase and serotonin were expressed in 80%, 43% and 77% of cases of prostate carcinoma and in 29%, 10% and 36% of hyperplastic tissue, respectively. Larger prostates had no higher content of various neuroendocrine cells than smaller prostates. There was higher expression of neuropeptides in carcinomatous than in hyperplastic tissue. Of the 3 peptides chromogranin A was significantly related to all parameters, including Gleason score, tumor stage, PSA and patient survival. In addition to PSA, neuron specific enolase was also closely associated with other clinicopathological parameters. Serotonin was significantly related to patient survival only but we noted no correlation with Gleason score, tumor stage or PSA. In regard to factors predictive of patient prognosis expression of the 3 neuropeptides in tumor cells, Gleason score, tumor stage and PSA were closely related to patient survival in this study

CONCLUSIONS

The growth of hyperplastic prostate tissue is related to neuroendocrine cell activity. The chromogranin A marker has the highest expression in prostate cancer. Neuroendocrine cells may represent an independent indicator of poor prognosis in patients with prostate carcinoma.

The lung is the major site that produces nitric oxide to induce acute pulmonary oedema in endotoxin shock

1. The present study was undertaken to determine the locus of nitric oxide (NO) production that is toxic to the lung and produces acute pulmonary oedema in endotoxin shock, to examine and compare the effects of changes in lung perfusate on endotoxin-induced pulmonary oedema (EPE) and to evaluate the involvement of constitutive and inducible NO synthase (cNOS and iNOS, respectively). 2. Experiments were designed to induce septic shock in anaesthetized rats with the administration of Escherichia coli lipopolysaccharide (LPS). Exhaled NO, lung weight (LW)/bodyweight (BW) ratio, LW gain (LWG) and lung histology were measured and observed to determine the degree of EPE 4 h following LPS. The EPE was compared between groups in which LPS had been injected either into the systemic circulation or into the isolated perfused lung. The lung perfusate was altered from whole blood to physiological saline solution (PSS) with 6% albumin to test whether different lung perfusions affected EPE. Pretreatment with various NOS inhibitors was undertaken 10 min before LPS to investigate the contribution of cNOS and iNOS to the observed effects. 3. Endotoxin caused profound systemic hypotension, but little change in pulmonary arterial pressure. The extent of EPE was not different between that induced by systemic injection and that following administration to isolated lungs preparations. Replacement of whole blood with PSS greatly attenuated (P < 0.05) EPE. In blood-perfused lungs, pretreatment with NOS inhibitors, such as Nomega-nitro-L-arginine methyl ester, aminoguanidine and dexamethasone, significantly prevented EPE (P < 0.05). 4. The major site of NO production through the whole blood is in the lung. The NO production mediated by the iNOS system is toxic to the endothelium in the pulmonary microvasculature. Inhalation of NO for patients with sepsis may be used with clinical caution. Therapeutic consideration of lung extracorporeal perfusion with PSS and pharmacological pretreatment with iNOS inhibitors may be warranted.

Severe exercise enhances phagocytosis by murine bronchoalveolar macrophages

Because physical activity affects the immune competency of individuals by an unknown mechanism, we investigated the effect of acute exercise on phagocytosis of bronchoalveolar macrophages (BAMs). Male BALB/c mice, 7-9 weeks old, ran on a treadmill to exhaustion (severe exercise, SE) or at a final speed of 17 m/min for 30 min (moderate exercise, ME). Although both exercise protocols induced differential leukocytosis, 95% leukocytes from lung lavages of both groups were BAMs. The BAM phagocytic capacity of nonopsonized beads increased immediately after SE but not after ME, gradually returning to the basal level after 4 h. SE upregulates the macrophage scavenger receptors (SR-A type I/II and MARCO), CR3, and ICAM-1, but not Fc gammaR. Although the blocking effect of MARCO antibody was most pronounced, that of ICAM-1 antibody was totally reversed by cross-linking CR3. Our results showed that SE, but not ME, activated BAMs and that the enhanced nonopsonized phagocytosis was mainly mediated by scavenger receptors and ICAM-1/CR3.

Endothelial [Ca(2+)](i) signaling during transmigration of polymorphonuclear leukocytes

Vascular endothelium plays an important role in regulating the transendothelial migration of polymorphonuclear leukocytes (PMNs). In this study, the intracellular calcium ion ([Ca(2+)](i)) signaling of endothelial cells (ECs) during PMN transmigration was examined at the single-cell level. Human umbilical vein ECs were cultured on a thin layer of collagen gel. The ECs were labeled with fura-2, immersed in formyl-Met-Leu-Phe, and subsequently perfused with fresh buffer to establish a gradient of chemoattractant across the EC monolayer. The entire process of PMN rolling on, adhering to, and transmigrating across the EC monolayer was recorded under both phase-contrast and fluorescence optics. The data showed the following: (1) At high concentration (approximately 3 x 10(6)/mL), both PMN suspension and its supernatant stimulated frequent EC [Ca(2+)](i) elevations across the monolayer; (2) when used at lower concentration (approximately 5 x 10(5)/mL) to avoid the interference of soluble factors, PMN transmigration, but not rolling or adhesion, was accompanied by EC [Ca(2+)](i) elevation; (3) the latter EC [Ca(2+)](i) elevation occurred simultaneously in ECs adjacent to the transmigration site, but not in those that were not in direct contact with the transmigrating PMNs; (4) this EC [Ca(2+)](i) elevation was an initial and required event for PMN transmigration; and (5) PMNs pretreated with 5,5'-dimethyl-1, 2-bis(2-aminophenoxy)ethane-N, N, N', N'-tetraacetic acid transmigrated with the accompanying EC [Ca(2+)](i) elevation, but they became elongated in the collagen gel. In conclusion, PMNs induce adjacent EC [Ca(2+)](i) signaling, which apparently mediates the "gating" step for their subsequent transmigration. (Blood. 2000;96:3816-3822)

Invited review: effects of flow on vascular endothelial intracellular calcium signaling of rat aortas ex vivo

To study the effects of flow on in situ endothelial intracellular calcium concentration ([Ca(2+)](i)) signaling, rat aortic rings were loaded with fura 2, mounted on a tissue flow chamber, and divided into control and flow-pretreated groups. The latter was perfused with buffer at a shear stress of 50 dyns/cm(2) for 1 h. Endothelial [Ca(2+)](i) responses to ACh or shear stresses were determined by ratio image analysis. Moreover, ACh-induced [Ca(2+)](i) elevation responses were measured in a calcium-free buffer, or in the presence of SKF-96365, to elucidate the role of calcium influx in the flow effects. Our results showed that 1) ACh increased endothelial [Ca(2+)](i) in a dose-dependent manner, and these responses were incremented by flow-pretreatment; 2) the differences in ACh-induced [Ca(2+)](i) elevation between control and flow-pretreated groups were abolished by SKF-96365 or by Ca(2+)-free buffer; and 3) in the presence of 10(-5) M ATP, shear stress induced dose-dependent [Ca(2+)](i) elevation responses that were not altered by flow-pretreatment. In conclusion, flow-pretreatment augments the ACh-induced endothelial calcium influx in rat aortas ex vivo.

Effects of chronic exercise on calcium signaling in rat vascular endothelium

Chronic exercise enhances endothelium-dependent vasodilating responses. To investigate whether this is due to a change in endothelial Ca(2+) signaling, we examined intracellular Ca(2+) concentration ([Ca(2+)](i)) level in rat aortic endothelium in response to acetylcholine (ACh) or ATP. Four-week-old male Wistar rats were divided into control and exercise groups. The exercised animals ran on a treadmill at a moderate intensity for 60 min/day, 5 day/wk, for 10 wk. Rat aortas were then excised and loaded with fura 2. After the aortas were mounted on a flow chamber, these specimens were observed under an epifluorescence microscope equipped with ratio-imaging capability. Our results showed that 1) chronic exercise increased both ACh- and ATP-induced [Ca(2+)](i) responses; 2) ACh induced heterogeneous [Ca(2+)](i) elevation in individual endothelial cells; and 3) the exercise effect on ACh-evoked endothelial [Ca(2+)](i) elevation was inhibited by the Ca(2+) influx blocker SKF-96365, by a Ca(2+)-free buffer, or by high concentrations of extracellular K(+). We conclude that chronic exercise increases ACh-induced [Ca(2+)](i) elevation in rat aortic endothelium in situ, possibly by facilitating Ca(2+) influx.

Successful treatment of azoospermia secondary to ejaculatory duct cyst

Ejaculatory duct obstruction is considered a rare cause of infertility. Two cases are reported of an ejaculatory duct cyst with azoospermia preoperatively diagnosed by transrectal ultrasonography. The diagnosis of ejaculatory duct obstruction in one patient was confirmed by vasography with a combined iodinated contrast medium and methylene blue solution for radiological and direct visualization. Transrectal puncture and contrast filling of the cyst under the transrectal ultrasonographic guidance diagnosed the other patient. On the basis of these findings transurethral unroofing of the cyst was performed successfully. Transrectal ultrasonography facilitates evaluation and treatment of azoospermia caused by ejaculatory duct obstruction and may minimize the need for more invasive studies in such cases.

Giant hydronephrosis of a duplex system associated with ureteral ectopia: a cause of retrograde ejaculation

Retrograde ejaculation is an extremely rare complication of the ectopic ureter or ectopic ureterocele. In the literature, only two cases have been reported worldwide. In this article the authors describe a patient who has a completely duplicated collecting system with massive dilatation of the upper pole system, which has manifested as a huge abdominal and retroperitoneal mass, complicated by retrograde ejaculation.

Localization of sympathetic postganglionic neurons innervating mesenteric artery and vein in rats

Physiological and histochemical studies have demonstrated the control and innervation of sympathetic nerves to the artery and vein vessels of splanchnic circulation. In our laboratory, we first used the technique of retrograde transport of horseradish peroxidase to identify the origin of sympathetic neurons innervating the mesenteric vein. In this study, double fluorescence staining technique was used for a simultaneous localization of the sympathetic postganglionic neurons supplying the mesenteric artery and vein in rats. First-order branches of mesenteric artery (A) and vein (V) in the vicinity of ileo-cecal junction were isolated for application of fluorescent dyes (Fast Blue, FB and Diamidino Yellow, DY). The application of FB and DY on A and V was alternated in the next animal to minimize the difference in dye uptake. The animal was allowed to recover for 6-7 days assuring a complete uptake of FB and DY into the cytoplasm and nucleus, respectively. The number of FB, DY and double staining neurons in the prevertebral and paravertebral ganglia were counted under a fluorescent microscope after animal fixation and serial frozen section (30 microm) of the sympathetic ganglia. Our study revealed the following findings: (1) Distribution of the fluorescence-staining neurons in the sympathetic ganglia was as follows: right celiac ganglion (39%), superior mesenteric ganglion (30%), left celiac ganglion (26%), inferior mesenteric ganglion (1%) and paravertebral ganglia (4%). (2) Double staining neurons that dually innervate A and V amounted to 54% of total staining neurons. There were 41% neurons singly innervating A and 5% innervating V. (3) The ratio of neurons supplying the A and V ranged from 1.41 to 1.75 (average 1.61). (4) There was no distinct topographical distribution with respect to the neuron location innervating A and V. The distribution of neurons appeared in a scattering pattern.

Preeclamptic pregnancy is associated with increased sympathetic and decreased parasympathetic control of HR

Previous work from our laboratory using heart rate variability (HRV) has demonstrated that women before menopause have a more dominant parasympathetic and less effective sympathetic regulations of heart rate compared with men. Because it is still not clear whether normal or preeclamptic pregnancy coincides with alternations in the autonomic functions, we evaluated the changes of HRV in 17 nonpregnant, 17 normotensive pregnant, and 11 preeclamptic women who were clinically diagnosed without history of diabetic neuropathy, cardiac arrhythmia, and other cardiovascular diseases. Frequency-domain analysis of short-term, stationary R-R intervals was performed to evaluate the total variance, low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), ratio of LF to HF (LF/HF), and LF in normalized units (LF%). Natural logarithm transformation was applied to variance, LF, HF, and LF/HF for the adjustment of the skewness of distribution. We found that the normal pregnant group had a lower R-R value and HF but had a higher LF/HF and LF% compared with the nonpregnant group. The preeclamptic group had lower HF but higher LF/HF compared with either the normal pregnant or nonpregnant group. Our results suggest that normal pregnancy is associated with a facilitation of sympathetic regulation and an attenuation of parasympathetic influence of heart rate, and such alterations are enhanced in preeclamptic pregnancy.

Heterogeneity of [Ca(2+)](i) signaling in intact rat aortic endothelium

Most existing knowledge about [Ca(2+)](i) signaling in vascular endothelium has been based on studies using endothelial cells cultured in vitro. To examine how endothelial cells behave in situ, we have developed a method to monitor single-cell [Ca(2+)](i) from Fura-2-loaded rat aortic segments. Fluorescence ratio images from large numbers of endothelial cells were acquired by using a flow chamber mounted on a dual-wavelength fluorescence microscope. Our results showed that either acetylcholine or histamine reversibly activated the vascular endothelium by eliciting M(3) or H(1) receptor-mediated [Ca(2+)](i) increases, respectively. The acetylcholine-evoked endothelial [Ca(2+)](i) elevation at the branch site (intercostal orifice) was much more pronounced than that at the non-branch area. However, endothelium at the branch site was relatively insensitive to histamine. Both acetylcholine-sensitive and histamine-sensitive endothelial cells were arranged in belts aligned along flow lines and were intercalated with each other. Data analyzed from 400 endothelial cells located at the non-branch site showed drastically heterogeneous [Ca(2+)](i) responses to a fixed concentration of either acetylcholine or histamine, differing by two orders of magnitude in individual cells. As a conclusion, vascular endothelial cells appear to have their own characteristic [Ca(2+)](i) 'fingerprint' to various agonists and they may function coordinately in situ.

Opposition of rapid baroreceptor resetting by prostanoids in rabbits

Arterial baroreceptors reset rapidly within minutes during acute hypertension; baroreceptor pressure threshold (Pth) is increased and the pressure-baroreceptor activity relation is shifted to the right. The purpose of the present study was to determine if prostacyclin (PGI2) or other prostanoids, released during acute hypertension modulate the magnitude of baroreceptor resetting. Baroreceptor activity was recorded from the vascularly-isolated carotid sinus during distension of the sinus with slow pressure ramp in rabbits anesthetized with chloralose. Pressure-activity curves were generated after holding carotid sinus pressure for 10-15 min from 30 to 100 mmHg. In control, the elevation of holding pressure increased Pth from 44+/- to 65+/-5 mmHg (p < 0.05, n = 12). In the presence of PGI2 (20 microM), Pth averaged 43+/-4 and 45+/-3 mmHg (n = 12) after holding pressure at 30 and 100 mmHg, respectively. In the control group before exposing the carotid sinus to indomethacin, an elevation of holding pressure increased Pth from 49+/-2 to 71+/-3 mmHg (p < 0.05, n = 12). After inhibition of the endogenous formation of prostanoids with indomethacin (20 microM), Pth increased by a significantly greater extent from 61+/-2 to 90+/-3 mmHg (p < 0.05, n = 12) with the increase in holding pressure. The slope of the pressure-activity curve (baroreceptor gain) was not influenced by the change in holding pressure. It was increased significantly by PGI2, while decreased by indomethacin. Neither the change in holding pressure nor PGI2 affected the circumferential wall strain of carotid sinus over a wide range of pressure alteration. The results suggest that PGI2 or other prostanoids released during acute hypertension sensitizes baroreceptors and provides a negative feedback mechanism that opposes and limits the magnitude of rapid baroreceptor resetting.

Effects of Welsh onion extracts on human platelet function in vitro

Welsh onion has been consumed for prevention of cardiovascular disorders. However, its underlying mechanisms are still unclear. This study investigated whether Welsh onion extracts can alter human platelet function (ie, platelet adhesion, aggregation, and thromboxane release). To clarify the underlying mechanisms, we also measured the intracellular calcium ([Ca2+]i) and cyclic nucleotide levels in platelets. Our results showed that 1) boiled extracts directly induced platelet aggregation in a dose-dependent manner; 2) raw extracts inhibited platelet adhesion and ADP-evoked platelet aggregation, while boiled extracts enhanced them; 3) raw green extract suppressed ADP-stimulated platelet [Ca2+]i elevation and thromboxane production, whereas boiled green extract enhanced them; 4) raw green extract elevated platelet cAMP level, whereas boiled green extract had no effect on cAMP level. Furthermore, the boiled green extract, but not the raw extract, induced pronounced platelet morphological changes. In conclusion, raw extracts of Welsh onion inhibit platelet function in vitro while boiled extracts activate platelets.

Chronic consumption of raw but not boiled Welsh onion juice inhibits rat platelet function

Welsh onion has been consumed for prevention of cardiovascular disorders. To study if it has antithrombotic effects, 9-wk-old male Sprague-Dawley rats were studied. Some rats were fed raw or boiled Welsh onion juice (2 g. kg(-1). d(-1)) for 4 wk, and the remaining acted as the control. Before and after feeding, their systolic blood pressure was measured by a tail-cuff method. Two days after the treatment period, tail bleeding time, platelet function (including platelet aggregation and adhesion), plasma levels of prostaglandins, and platelet cyclic nucleotide levels were determined. In comparison to the control, raw Welsh onion juice consumption significantly (1) lowered resting systolic blood pressure; (2) prolonged the bleeding time; (3) diminished platelet adhesion on a fibrinogen-coated surface, ADP-evoked platelet aggregation and ADP-stimulated thromboxane release; (4) elevated the concentration of cyclic AMP, but not cyclic GMP, in platelets; (5) increased the plasma level of 6-keto-prostaglandin F(1alpha), the stable prostacyclin metabolite, but not the plasma nitrite level. On the contrary, boiled Welsh onion juice consumption was totally ineffective. In conclusion, consuming raw Welsh onion juice, but not boiled juice, has blood pressure lowering and antithrombotic effects in rats. These effects may be mediated by PGI(2)-cAMP pathway.

Effects of intracranial hypertension on steady and pulsatile haemodynamics in dogs

1. Intracranial hypertension (ICH) tends to elicit various cardiovascular changes. Previous studies on the haemodynamic responses to ICH have been confined mainly to measurements of arterial pressure (AP), cardiac output (CO) and total peripheral resistance (TPR). In the present study, we used the technique of arterial impedance analysis for a complete assessment of steady and pulsatile haemodynamics in ICH. 2. In anaesthetized dogs, aortic pressure and flow waves were obtained with high-fidelity Millar sensors. The pressure and flow waves were subjected to Fourier transformation (frequency analysis) for an analysis of impedance spectra. Intracranial pressure (ICP) was elevated by inflation of an epidural balloon. At an ICP of 50 mmHg, the changes in steady and pulsatile haemodynamics were slight. 3. Haemodynamic changes became evident at an ICP of 100 mmHg. The mean AP was elevated by 31 mmHg (+32%) and heart rate (HR) was reduced by 25 b.p.m. (-18%). There was also a significant decrease in CO by 27% and large increase in TPR by 82%. With respect to pulsatile haemodynamics, an elevation of ICP to 100 mmHg caused significant increases in characteristic impedance by 45% and wave reflection by 53%. Arterial compliance was reduced by 50%. The ventricular oscillatory work was increased without a significant change in steady work. 4. The results indicate that ICH causes constriction of resistance vessels to affect AP and TPR. Because the pulsatile haemodynamics reflect mainly the Windkessel functions, ICH also induces stiffness of the large vessels to affect arterial impedance, pulse wave reflection and ventricular oscillatory work.

Antioxidant administration inhibits exercise-induced thymocyte apoptosis in rats

PURPOSE

The purpose of this study was to investigate the effect of antioxidant on exercise-induced apoptosis in rat thymocytes.

METHODS

After exercise at 13.8 m x min(-1) for 60-90 min x d(-1) on a motor-driven drum exerciser for 2 consecutive days, rat thymocyte apoptosis was monitored by the feature of DNA fragmentation. To study the effect of antioxidant, rats were administered with butylated hydroxyanisole (BHA) for 7 d before exercise.

RESULTS

Exercise could induce thymocyte DNA fragmentation as detected on electrophoretic gel and by cell death detection ELISA kit. Further studies indicated that pretreatment with antioxidant BHA to rats resulted in a blockage of exercise-induced DNA fragmentation. The concentrations of glutathione (GSH) were not significantly changed in rat thymocytes after exercise with or without BHA treatment.

CONCLUSION

These results suggest that reactive oxygen species may play a role in thymocyte apoptosis induced by exercise. However, changes in GSH levels were not observed in this exercise model.

Hemodynamic and neurohumoral changes after abdominal aortic constriction in rats

Cardiac after-load, neurohumoral reaction and the secondary cardiac hypertrophy were studied in six groups of Sprague-Dawley (SD) rats with abdominal aortic constriction. We found that abdominal aortic constriction above the renal arteries decreased the heart rate and cardiac output, and increased the pulse pressure. These abnormalities would return to normal after constriction ended. Captopril, propranolol and prazosin could reduce the increase of pulse pressure but still had decreased in cardiac output of rats with abdominal constriction. Aortic constriction also increased the aortic impedance and cardiac load but decreased aortic compliance. These changes could also be lessened by captopril, propranolol and prazosin. We have confirmed that aortic constriction can induce secondary cardiac hypertrophy, but the pathogenesis might be due to multiple factors.

[Neural and hemodynamic mechanisms of neurogenic pulmonary edema]

Acute pulmonary edema has been reported in man and animals with intracranial disorders, head trauma or cerebral compression. In anesthetized rats, cerebral compression produced acute, fulminating and fatal lung injury. Intense activation of the sympathetic mechanism in the brain stem induced systemic hypertension and a series of hemodynamic changes. Pulmonary volume loading was the result of drastic decrease in aortic flow accompanying a decline in pulmonary arterial flow. The acute increase in pulmonary blood volume caused severe rises in pulmonary arterial and venous pressures leading to disruption of lung vessels.

Chronic exercise enhances vascular responses to clonidine in rats by increasing endothelial alpha2-adrenergic receptor affinity

Chronic exercise increases endothelium-dependent vasodilating responses. To investigate whether endothelial alpha2-adrenergic receptor upregulation is involved in the enhancement of clonidine-induced vasorelaxation by chronic exercise, 4-week-old male Wistar rats were used. They were divided into control and exercise groups. The trained animals ran on a treadmill at a moderate intensity for 60 min per day, 5 days per week for 10 weeks in total. Resting heart rates were measured by a tail-cuff method to confirm training effects. After training, rings of the thoracic aorta were prepared to evaluate vasodilating responses to clonidine, an alpha2 agonist. Released endothelium-derived relaxing factors were pharmacologically identified by treatment of N(omega)-nitro-L-arginine, a nitric oxide (NO) synthase inhibitor, or tetraethylammonium chloride, an endothelium-derived hyperpolarization factor (EDHF) inhibitor. Receptor binding assays were performed by using 3H-labeled clonidine as a tracer. We found that chronic exercise enhanced vascular responses to clonidine by stimulating the release of both NO and EDHF. It also increased the binding affinity of endothelial cell alpha2 receptor without changing the number of binding sites. Therefore, the elevated vasorelaxing responses to clonidine after chronic exercise may be partially resulted from an increase in endothelial alpha2 receptor binding affinity.

Welsh onion (Allium fistulosum L.) extracts alter vascular responses in rat aortae

Welsh onion, a member of the genus Allium, has been consumed for prevention of cardiovascular disorders. However, its underlying mechanisms are still unclear. We investigated whether Welsh onion extracts (green or white portion, raw or boiled) can alter vascular responses in vitro in the thoracic aortae of Sprague-Dawley rats. The possible roles of endothelium-derived factors in the Welsh onion extract-induced vascular responses were examined by applying various inhibitors, such as Nomega-nitro-L-arginine (10(-4) M), tetraethylammonium (10(-3) M), and SQ29548 (10(-5) M). Our results showed that Welsh onion extracts caused vasodilation on precontracted vessel rings. These effects were most pronounced in vessel rings treated with raw green-leaf extract (RG). Low doses of RG induced vasorelaxation, which was mediated by endothelium-derived nitric oxide. High doses of RG induced endothelium-independent vasorelaxation. On the other hand, the boiled Welsh onion extract also stimulated the release of an endothelium-derived contracting factor, which might be thromboxane A2. We conclude that Welsh onion extract can modulate vascular tone in both endothelium-dependent and endothelium-independent manners.

Effects of nitric oxide synthase inhibitors on systemic hypotension, cytokines and inducible nitric oxide synthase expression and lung injury following endotoxin administration in rats

Endotoxin shock is characterized by systemic hypotension, hyporeactiveness to vasoconstrictors and acute lung edema. A nitric oxide synthase (NOS) inhibitor, NG-monomethyl-L-arginine (L-NMMA) has been shown to be effective in reversing acute lung injury. In the present study, we evaluated the effects of NOS blockade by different mechanisms on the endotoxin-induced changes. In anesthetized rats, lipopolysaccharide (LPS, Klebsiella pneumoniae) was administered intravenously in a dose of 10 mg/kg. LPS caused sustained systemic hypotension accompanied by an eightfold increase of exhaled NO during an observation period of 4 h. After the experiment, the lung weight was obtained and lung tissues were taken for the determination of mRNA expressions of inducible NOS (iNOS), interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha-(TNF-alpha). Histological examination of the lungs was also performed. In the control group injected with saline solution, mRNA expressions of iNOS, IL-1beta and TNF-alpha were absent. Four hours after LPS, the mRNA expressions of iNOS and IL-1beta were still significantly enhanced, but TNF-alpha was not discernibly expressed. LPS also caused a twofold increase in lung weight. Pathological examination revealed endothelial damage and interstitial edema. Various NOS inhibitors were given 1 h after LPS administration. These agents included Nomega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), a constitutive NOS and iNOS inhibitor; S, S'-1,4-phenylene-bis-(1,2-ethanedinyl) bis-isothiourea dihydrobromide (1,4-PBIT, 10 mg/kg), a relatively specific iNOS inhibitor, and dexamethasone (3 mg/kg), an inhibitor of iNOS expression. These NOS inhibitors all effectively reversed the systemic hypotension, reduced the exhaled NO concentration and prevented acute lung injury. The LPS-induced mRNA expressions of iNOS and IL-1beta were also significantly depressed by these NOS inhibitors. Our results suggest that NO production through the iNOS pathway is responsible for endotoxin-induced lung injury. Certain cytokines such as IL-1beta are possibly involved. These changes are minimized by NOS inhibitors through different mechanisms.

Effects of nitric oxide synthase inhibitors on systemic hypotension, cytokines and inducible nitric oxide synthase expression and lung injury following endotoxin administration in rats

Endotoxin shock is characterized by systemic hypotension, hyporeactiveness to vasoconstrictors and acute lung edema. A nitric oxide synthase (NOS) inhibitor, NG-monomethyl-L-arginine (L-NMMA) has been shown to be effective in reversing acute lung injury. In the present study, we evaluated the effects of NOS blockade by different mechanisms on the endotoxin-induced changes. In anesthetized rats, lipopolysaccharide (LPS, Klebsiella pneumoniae) was administered intravenously in a dose of 10 mg/kg. LPS caused sustained systemic hypotension accompanied by an eightfold increase of exhaled NO during an observation period of 4 h. After the experiment, the lung weight was obtained and lung tissues were taken for the determination of mRNA expressions of inducible NOS (iNOS), interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha-(TNF-alpha). Histological examination of the lungs was also performed. In the control group injected with saline solution, mRNA expressions of iNOS, IL-1beta and TNF-alpha were absent. Four hours after LPS, the mRNA expressions of iNOS and IL-1beta were still significantly enhanced, but TNF-alpha was not discernibly expressed. LPS also caused a twofold increase in lung weight. Pathological examination revealed endothelial damage and interstitial edema. Various NOS inhibitors were given 1 h after LPS administration. These agents included Nomega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), a constitutive NOS and iNOS inhibitor; S, S'-1,4-phenylene-bis-(1,2-ethanedinyl) bis-isothiourea dihydrobromide (1,4-PBIT, 10 mg/kg), a relatively specific iNOS inhibitor, and dexamethasone (3 mg/kg), an inhibitor of iNOS expression. These NOS inhibitors all effectively reversed the systemic hypotension, reduced the exhaled NO concentration and prevented acute lung injury. The LPS-induced mRNA expressions of iNOS and IL-1beta were also significantly depressed by these NOS inhibitors. Our results suggest that NO production through the iNOS pathway is responsible for endotoxin-induced lung injury. Certain cytokines such as IL-1beta are possibly involved. These changes are minimized by NOS inhibitors through different mechanisms.

Modulatory effect of blood cells on hypoxic vasoconstriction response and nitric oxide release in rat lungs

In this study, we investigated the modulatory effects of different types of blood cells on hypoxic pulmonary vasoconstrictive (HPV) response and nitric oxide (NO) release in isolated rat lungs. The lungs were perfused at a constant flow with physiologic saline solution (PSS). The changes in pulmonary arterial pressure (PAP) and NO release were observed. Two hypoxic challenges with a 5% CO2-95% N2 gas mixture were carried out in each experiment. Hypoxia induced pulmonary vasoconstriction, as reflected by an increase in PAP (0.88 +/- 0.22 cmH2O). At the same time, NO (342.9 +/- 78.3 mv) release from the lungs was also increased. Addition of white blood cells (WBCs, 0.70 to 0.88 x 10(5)/mL), platelets (1.48 to 1.96 x 10(5)/mL), or red blood cells (RBCs, 4.6 to 6.6 x 10(5)/mL) into the perfusate produced different effects on PAP and NO changes. WBCs decreased the pulmonary vasoconstriction response and this was accompanied by an increase in NO release. Platelets had no significant effects on either PAP or NO. RBCs significantly potentiated the PAP increase and attenuated the NO release. The results indicate that NO release during hypoxia tends to offset pulmonary vasoconstriction and that NO release and HPV response are modulated by different cell elements.

Effects of chronic exercise on muscarinic receptor-mediated vasodilation in rats

Previous studies have demonstrated that vascular responses to acetylcholine (ACh), an endothelium-dependent vasodilator, are enhanced in exercise-trained animals. In order to see if chronic exercise upregulates endothelial muscarinic (M) receptor, the subtype of M receptors responsible for ACh-induced vasorelaxation in the thoracic aorta of male Wistar rats was characterized first, then a receptor assay was performed. These animals were divided into exercise and control groups. The trained rats ran on a treadmill with a moderate intensity for 60 min per day, 5 days per week. After 10 weeks of training, rats were decapitated and their thoracic aortae were isolated. The subclass of M receptor in endothelium was pharmacologically identified on the basis of selective affinity of antagonists; ie, pirenzepine for M1, gallamine for M2, and 4-diphenylacetoxy-N-methylpiperidine methiodide for M3. Our results showed that in the thoracic aorta of Wistar rats, 1) ACh-induced vasorelaxation was mediated by M3 receptor; 2) chronic exercise enhanced ACh-evoked vasodilating responses. However, this alteration was not caused by receptor upregulation, as maximal binding sites and affinity of M3 receptor were not changed by chronic exercise. Other possible mechanisms need to be further studied.

Development and evaluation on transdermal delivery of enoxacin via chemical enhancers and physical iontophoresis

Iontophoresis and enhancers were performed to enhance percutaneous absorption of enoxacin so as to compare the enhancement between these two enhancing methods. The cationic surfactant of benzalkonium chloride showed the highest enhancing activity for enoxacin for all pH values of buffer vehicles. The enhancement factor of sodium laurylsulfate showed a dose-dependent property between the range of 0.1% to 3.0% concentration. Nonionic surfactant of Polysorbate 80 did not exhibit any enhancing effect on the percutaneous absorption of enoxacin. The highest enhancement factor of iontophoretic delivery was observed at pH 5.0 solution of anodal iontophoresis for cationic enoxacin. The cathodal iontophoresis of negative molecules and anodal iontophoresis of neutral molecules showed lower enhancing effect for enoxacin. The fact that the skin residuals of enoxacin after iontophoresis showed both tremendous and current density-dependent amounts for cationic enoxacin suggested local skin and soft tissue infections might be treated by this physical enhancement method. Combination of benzalkonium chloride and iontophoresis exerted a synergistic effect for anionic enoxacin in pH 10.0, which was possibly due to the shielding of negative charge in skin and the water molecules carried by chloride.

Prevalence of diabetes mellitus and impaired glucose tolerance in Aborigines and Chinese in eastern Taiwan

The aim of this study was to determine the prevalence of diabetes mellitus and impaired glucose tolerance (IGT) in three different ethnic groups in eastern Taiwan. The study was performed among Han Chinese, aboriginal Ami and aboriginal Atayal in six rural villages. Inhabitants aged 40 years and over were invited to participate. A 75-g oral glucose tolerance test (OGTT) was used as suggested by the World Health Organization (WHO) for population screening purposes. WHO criteria were used for determining the results. A total of 1013 adults (460 men and 553 women) were examined with a response rate of 62.1%. There were no significant differences in sex, age and history of diabetes between responders and non-responders. The age-adjusted prevalence of diabetes was 11.0% (9.8% in men and 12.3% in women) in the Chinese, 9.1% (12.1% in men and 7.4% in women) in the Amis, 10.8% (11.5% in men and 9.4% in women) in the Atayal and 9.9% (11.5% in men and 8.5% in women) for the two aboriginal groups together. Although sex differences in prevalence of diabetes were not statistically significant, it seems that diabetes was slightly more prevalent in Chinese women than in Chinese men (12.3 versus 9.8%). Nonetheless, the prevalence rate of diabetes was somewhat higher in the aboriginal males than in the aboriginal females (12.1 versus 9.8% for Ami and 11.5 versus 10.7% for Atayal). The prevalence of IGT was 7.2, 8.5, 10.8 and 9.7% for the Chinese, Amis, Atayal and the two aboriginal groups, respectively. There were no substantial differences in the prevalence of diabetes and IGT among these three ethnic groups. Environment, rather than ethnicity, was more likely the predominant factor. It was found that the prevalence of diabetes in this study was about twice as high as that reported in a 1987 survey in Taiwan. The discrepancy may be due to different screening methods and assessment periods.

Effects of chronic exercise and deconditioning on platelet function in women

To investigate the effects of chronic exercise and deconditioning on platelet function in women, 16 healthy sedentary women were divided into control and exercise groups. The exercise group cycled on an ergometer at 50% maximal oxygen consumption for 30 min/day, 5 days/wk, for two consecutive menstrual cycles and then were deconditioned for three menstrual cycles. During this period, platelet adhesiveness on a fibrinogen-coated surface, ADP-induced platelet aggregation and intracellular calcium concentration elevation, guanosine 3',5'-cyclic monophosphate (cGMP) content in platelets, and plasma nitric oxide metabolite levels were measured before and immediately after a progressive exercise test in the midfollicular phase. Our results indicated that, after exercise training, 1) resting heart rates and blood pressures were reduced, and exercise performance was improved; 2) resting platelet function was decreased, whereas plasma nitrite and nitrate levels and platelet cGMP contents were enhanced; and 3) the potentiation of platelet function by acute strenuous exercise was decreased, whereas the increases in plasma nitrite and nitrate levels and platelet cGMP contents were enhanced by acute exercise. Furthermore, deconditioning reversed these training effects. This implies that training-induced platelet functional changes in women in the midfollicular phase may be mediated by nitric oxide.

Acute effects of nitric oxide blockade with L-NAME on arterial haemodynamics in the rat

1. We employed the technique of impedance spectral analysis to investigate the role of endogenous nitric oxide (NO) in the regulation of steady and pulsatile haemodynamics in Wistar Kyoto rat (WKY). 2. A total of 12 WKYs was anaesthetized with pentobarbitol sodium (40 mg kg-1, i.p.) and artificially ventilated with an animal respirator. The aortic pressure wave was monitored with a high fidelity Millar sensor, and aortic flow wave with an electromagnetic flow probe. The pressure and flow waves were subjected to Fourier transform for the analysis of impedance spectra. 3. The baseline cardiovascular parameters were mean arterial pressure (APm) 95 +/- 9 mmHg, heart rate (HR) 338 +/- 9 b.p.m., stroke volume (SV) 0.23 +/- 0.01 ml, cardiac output (CO) 77.8 +/- 1.6 ml min-1, total peripheral resistance (TPR) 98 +/- 11 (x10(3)) dyne s cm-5, characteristic impedance (Zc) 2046 +/- 141 dyne s cm-5, arterial compliance at mean AP (Cm) 3.78 +/- 0.22 microliters mmHg-1 and backward pulse wave (Pb) 12.9 +/- 0.6 mmHg. 4. An NO synthase inhibitor, NG-nitro-L-arginine monomethyl ester (L-NAME) was administered at graded intravenous doses. This agent caused dose-dependent increases in AP and TPR with decreases in HR. At an accumulative dose of 10 mg kg-1, APm was increased by 29 +/- 3 mmHg (+31%) and TPR by 49 +/- 6 (x10(3)) dyne s cm-5 (+50%), while HR was reduced by 37 +/- 5 b.p.m. (-11%) and CO by 10.4 +/- 0.8 ml min-1 (-14%). The pulsatile haemodynamics including Zc and Pb were slightly increased by 14-15%. Cm was decreased by 1.09 microliters mmHg-1 (-29%). L-NAME also did not significantly affect the ventricular work including the steady, oscillatory and total work. 5. Aminoguanidine, a specific inhibitor for inducible NO synthase (iNOS), in dose 10-60 mg kg-1 i.v. did not alter the AP, HR and other parameters. The result indicated that blockade of constitutive NOS, but not iNOS is involved in these changes. 6. Angiotensin II (Ang) in various infusion doses was used to produce a profile of AP increase similar to that caused by L-NAME. Ang remarkably increased Zc, while TPR was moderately elevated. The pattern of haemodynamic changes was different from that following L-NAME. 7. The results suggest that blockade of the endogenous NO affects predominantly the arterial pressure and peripheral resistance. The Windkessel functions such as arterial impedance and pulse wave reflection are slightly increased. Ventricular works are not significantly altered.

Endogenous nitric oxide on arterial hemodynamics: a comparison between normotensive and hypertensive rats

Endogenous nitric oxide (NO) plays an important role in maintaining a vasodilator tone. In the present study, we compared the effects of NO blockade on the steady and pulsatile components of arterial hemodynamics between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto strain (WKY), 22-26 wk of age. In the first series of experiments, various doses (1-30 mg/kg i.v.) of N(G)-nitro-L-arginine methyl ester (L-NAME) were administered to block the NO release in anesthetized WKY and SHR. In both WKY and SHR, L-NAME caused a dose-dependent increase in arterial pressure (AP) with a decrease in heart rate (HR). The maximal effects of L-NAME on AP and HR occurred at a dose of 10 mg/kg. Both the AP increase and HR decrease were higher in SHR (AP, +38 +/- 4 mmHg; HR, -49 +/- 5 beats/min) than WKY (AP, +22 +/- 3 mmHg; HR, -33 +/- 5 beat/min). In other series, the technique of impedance spectral analysis was employed to investigate the effects of L-NAME (10 mg/kg i.v.) on the arterial hemodynamics. The aortic pressure and flow waves were recorded and subjected to Fourier transform for the analysis of impedance spectra. Both in WKY (n = 12) and in SHR (n = 12), L-NAME significantly increased AP and total peripheral resistance (TPR). The pulsatile and frequency-dependent hemodynamics including characteristic impedance, wave reflection, and ventricular work were only slightly altered. Despite higher resting values of AP and TPR in SHR (mean AP, 154 +/- 7 mmHg; mean TPR, 204 +/- 17 x 10(3) dyn x s x cm(-5)) than WKY (mean AP, 94 +/- 6 mmHg; mean TPR, 98 +/- 12 x 10(3) dyn x s x cm(-5)), the magnitudes of AP and TPR increments after NO blockade were significantly higher in SHR (AP, +37 +/- 3 mmHg; TPR, +124 +/- 16 x 10(3) dyn x s x cm(-5)) than in WKY (AP, +24 +/- 3 mmHg; TPR, +45 +/- 7 x 10(3) dyn x s x cm(-5)). The continuous formation of endogenous NO affects predominantly the AP and peripheral resistance in both WKY and SHR. The windkessel functions, such as impedance spectra, pulse-wave reflection, and ventricular work, are less affected after NO blockade. In addition, the effects of NO release on the AP and TPR appear to be enhanced in rats with established hypertension.

Role of prostaglandins in regulation of cerebral blood flow during acute hypertension

Endothelium-derived prostaglandins appear to play an important role in myogenic contraction of the cerebral arteries in response to increased transmural pressure. The goal of this study was to determine whether prostaglandins contribute to the autoregulatory response of cerebral blood flow (CBF) during acute hypertension in normotensive and chronically hypertensive animals. In 4-5 months old Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) anesthetized with pentobarbital sodium (45 mg/kg, i.p.), regional CBF of the right parietal cortex was monitored by laser-Doppler flowmetry. Acute hypertension was induced by intravenous infusion of phenylephrine and the elevated arterial pressure was maintained for 50 seconds for the measurement of CBF. In the control group of WKY rats, CBF increased by 5.6% per 10-mmHg increase in arterial pressure. Changes in CBF were similar between the initial state (0-10 seconds) and the steady state (30-40 seconds) of acute hypertension. In WKY rats pretreated with indomethacin (10 mg/kg, i.v.), increases in CBF in the initial state were slightly but significantly greater than that in the steady state. Indomethacin also tended to enhance the increases in CBF in both the initial state and the steady state; however, the effect was not significant. In the control group and indomethacin-pretreated group of SHR, acute hypertension produced similar increases in CBF. In both groups, no significant difference between changes in CBF in the initial state and the steady state was observed. Thus our findings suggest that 1) in normotensive animals, the early autoregulatory response of CBF during acute hypertension is partially mediated by prostaglandins and 2) the role of prostaglandins in the regulation of CBF during acute hypertension is altered in chronically hypertensive animals.

Effects of short-term exercise on female platelet function during different phases of the menstrual cycle

Previous studies have shown that premenopausal women have a low incidence of cardiovascular diseases, and that acute exercise affects male platelet function in an intensity-dependent manner. To investigate whether acute exercise affects female platelet function differently from males, sixteen sedentary women in the midfollicular phase or midluteal phase received strenuous or moderate exercise on a bicycle ergometer. Before and immediately after exercise, platelet adhesiveness, adenosine diphosphate-induced platelet aggregation and intracellular calcium concentration elevation, platelet cAMP and cGMP contents, urinary 11-dehydro-TXB2 and 6-keto-prostaglandin F1 alpha levels, and plasma nitric oxide metabolite level were determined. Our results showed no differences in exercise performance and in resting platelet function between two menstrual phases, with little change in urinary eicosanoid metabolites and platelet cAMP levels under all experimental conditions. In addition, for women in the midfollicular phase, (1) strenuous exercise increased platelet adhesiveness, adenosine-diphosphate-induced platelet aggregation, and intracellular calcium concentration elevation, whereas moderate exercise suppressed them; (2) moderate exercise enhanced plasma nitric oxide metabolite and platelet cGMP levels. In contrast, none of these platelet functions was affected by acute exercise in the midluteal phase. Therefore, we conclude that acute exercise affects female platelet function in an intensity-dependent manner in the midfollicular phase but not in the midluteal phase. The irresponsiveness of platelets to acute exercise in the luteal phase may partially explain why premenopausal women have a lower incidence of cardiovascular diseases than men.

Characterization of the WW domain of human yes-associated protein and its polyproline-containing ligands

We had previously identified the WW domain as a novel globular domain that is composed of 38-40 semiconserved amino acids and is involved in mediating protein-protein interaction. The WW domain is shared by proteins of diverse functions including structural, regulatory, and signaling proteins in yeast, nematode, and mammals. Functionally it is similar to the Src homology 3 domain in that it binds polyproline ligands. By screening a 16-day mouse embryo expression library, we identified two putative ligands of the WW domain of Yes kinase-associated protein which we named WW domain-binding proteins 1 and 2. These proteins interacted with the WW domain via a short proline-rich motif with the consensus sequence of four consecutive prolines followed by a tyrosine. Herein, we report the cDNA cloning and characterization of the human orthologs of WW domain-binding proteins 1 and 2. The products encoded by these cDNA clones represent novel proteins with no known function. Furthermore, these proteins show no homology to each other except for a proline-rich motif. By fluorescence in situ hybridization on human metaphase chromosomes, we mapped the human genes for WW domain-binding proteins 1 and 2 to chromosomes 2p12 and 17q25, respectively. In addition, using site-directed mutagenesis, we determined which residues in the WW domain of Yes kinase-associated protein are critical for binding. Finally, by synthesizing peptides in which the various positions of the four consecutive proline-tyrosine motif and the five surrounding residues were replaced by all possible amino acid residues, we further elucidated the binding requirements of this motif.

Pulmonary edema induced by phorbol myristate acetate is attenuated by compounds that increase intracellular cAMP

We have investigated the effect of terbutaline, aminophylline and dibutyryl cyclic AMP (DBcAMP) on phorbol myristate acetate (PMA)-induced acute lung injury in isolated, blood-perfused rabbit lungs. Pulmonary arterial pressure and lung weight were measured for 30 min after a bolus injection of PMA (10 mu g/kg). In the group exposed to PMA alone, the mean pulmonary arterial pressure (PAP) increased from 16.33 + or - 1.28 to 77.30 + or - 6.40 mmHg (P <0.001), and lung weight increased by 70.69 + or - 10.94 g during the 30 min after PMA challenge (P<0.001). Pretreatment with terbutaline, aminophylline or DBcAMP prevented the increases in both PAP and lung weight (P <0.001). Each of the three drugs also prevented the increase in pulmonary vascular permeability induced by PMA: terbutaline, aminophylline, and DBcAMP all significantly reduced the pulmonary capillary filtration coefficient (KfC) as well as the albumin concentration in the lung lavage fluid after PMA exposure. Post-treatment with terbutaline 5 min after PMA administration also had a protective effect. The mechanisms responsible for these protectivp3 effects may all involve an increase in intracellular cAMP, since all three drugs increase cAMP in the lung (though by different mechanisms). Our data further indicate that the inhibition of tumor necrosis factor production may likewise play an important role in the protective effect exerted by these drugs.

Chronic exercise decreases adrenergic agonist-induced vasoconstriction in spontaneously hypertensive rats

This study was conducted to investigate the effects of chronic exercise on adrenergic agonist-induced vascular responses in spontaneously hypertensive rats (SHR). Four-week-old male SHR and Wistar-Kyoto rats were divided into control and trained groups. The trained groups ran on a drum exerciser at 70% of peak oxygen consumption for 60 min/day 5 days/wk for 10 wk. Resting systolic blood pressure and heart rate were measured by a tail-cuff method, and changes in these parameters were considered as indexes of effective training. At the end of experiments, thoracic aortas and carotid arteries were isolated. Vasoconstricting responses to norepinephrine (NE) or phenylephrine (PHE) were studied. To clarify the role of endothelium-derived nitric oxide (EDNO) in the alteration of NE-induced vasoconstriction after chronic exercise, we measured the changes in vasoconstricting responses to NE (10(-8) M) after treatment with N omega-nitro-L-arginine. Vasorelaxing responses to PHE or clonidine were also studied. Our results showed that 1) vasoconstricting responses to NE or PHE in the endothelium-intact thoracic aorta were reduced, whereas PHE- or clonidine-induced EDNO release was enhanced by exercise training, and 2) the latter could be eliminated by N omega-nitro-L-arginine. Therefore, training may decrease adrenergic agent-induced vasoconstricting responses by increasing their stimulated EDNO release in hypertensive and normotensive rats.

Changes in cytosolic calcium concentrations and cell morphology in single platelets adhered to fibrinogen-coated surface under flow

Changes in intracellular calcium concentration [Ca2+]i of fura-2-loaded human platelet during its adhesion to a fibrinogen-coated surface were studied, using a flow chamber mounted on an epifluorescence microscope equipped with digital-ratio imaging. Adherent platelets were individually mapped under a scanning electron microscope to establish the possible correlation between adhesion-associated shape alterations and [Ca2+]i changes. We found that 1) there was no immediate [Ca2+]i elevation on platelet adhesion; 2) [Ca2+]i changes varied drastically platelets with a lag time ranging 10 to 200 s, averaging about 1 minute; 3) the pattern of [Ca2+]i changes varied drastically among individual adherent platelets; 4) the degree of [Ca2+]i elevation appeared to correlate with the extent of morphology change, with the vast majority ( > 90%) of spread platelets showed detectable [Ca2+]i changes; 5) neither morphological nor [Ca2+]i changes correlated with the lag time; 6) platelets treated with dimethyl-BAPTA (15 mumol/L) underwent normal shape change without [Ca2+]i elevation; 7) cytochalasin D (10 mumol/L) inhibited both shape change and [Ca2+]i elevation; 8) colchicine (1 mmol/L) was ineffective in both regards. We conclude that although platelet adhesion-associated shape changes may be accompanied with heterogeneous [Ca2+]i changes that are microfilament-dependent, [Ca2+]i changes do not happen immediately after platelet-surface contact and they are not required for adherent platelets to undergo postcontact morphological changes.

Flow-induced detachment of adherent platelets from fibrinogen-coated surface

A study of the shear forces under which adherent platelets of different morphologies can be detached from surfaces was carried out using a newly designed tapered flow chamber, which covered the entire shear range of physiological circulation. Platelets that naturally settled on a fibrinogen-coated surface were exposed to shear flow and were subsequently processed for scanning electron microscopic observation. We found that 1) the density of platelets remaining after flow exposure decreased with local shear stress, 2) adherent platelets of different morphologies withstood different levels of shear stress: most round cells and 40% of the cells that had a few short pseudopods were detached at < 10 dyn/cm2, whereas most spread cells could withstand 50 dyn/cm2, 3) pulsatile flow was more effective in removing adherent platelets than equivalent steady flow, 4) cytochalasin D and colchicine retarded platelet shape change and made them more easily detached by shear forces, and 5) metabolic energy-depleted platelets spread readily and formed shear-resistant clumps. Our observations indicated that adherent platelets of different morphologies on a fibrinogen-coated surface could withstand different levels of flow shear stress.

Isolation and cultivation of aortic endothelial cells from spontaneously hypertensive rat with a modified tissue explant technique

In the present study, we successfully established a "tissue explant technique" to obtain high yield and purity of endothelial cells from the aorta of hypertensive and normotensive rats (SHR and WKY). Small pieces of aorta were placed on fibronectin precoated petri dishes. The effects of oxygenation in the tissue preparation stage, tilting of the petri dish during the explanting period and timing of the removal of tissue blocks from petri dishes were evaluated. These procedures appeared to be critical for cell survival, tissue adhesion and minimizing of non-endothelial cell contamination. The cultured endothelial cells were characterized by morphological, immunohistochemical and biochemical examination. The cultured cells from both SHR and WKY rats showed similar endothelial cell character, positive immunofluorescence staining for the von Willebrand factor, and uptake of acetylated low-density lipoprotein (DiI-ac-LDL). The secretory function of prostacylcin I2 (PGI2), thromboxane A2 and endothelin of cultured endothelial cells was measured. The results showed that the secretion of both PGI2 and endothelin was greater in SHR than in WKY rats, but that there was no difference in thromboxane A2 secretion. Therefore, our "tissue explant technique" can provide high yield and purity of endothelial cells with their specific biological function in vitro. It will permit us to further study the role of endothelial cells in the development of hypertension.

Effects of exercise training and deconditioning on platelet function in men

Platelets play an important role in the pathogenesis of cardiovascular disease. It has also been noticed that regular exercise can reduce the risk of cardiovascular disease. This is the first study to demonstrate that endurance exercise training may suppress platelet adhesiveness and aggregation and that deconditioning may reverse the training effects. Healthy male sedentary subjects were randomly divided into control and training groups. The trained men were trained on a bicycle ergometer at about 60% of maximal oxygen consumption for 30 minutes per day, 5 days per week for 8 weeks, then deconditioned for 12 weeks. During the experimental period, blood samples of the trained subjects were collected before and immediately after a progressive exercise test every 4 weeks. The same experiments were applied to the controls at the beginning of this study and 8 weeks thereafter. A tapered parallel-plate chamber was used to assess platelet adhesiveness. Platelet aggregation induced by ADP was evaluated by the percentage of reduction in single platelet count. Our results showed that (1) platelet adhesiveness and aggregability were increased by short-term strenuous exercise in both control and trained groups, but the enhancement of platelet aggregability was decreased after exercise training in the trained subjects; (2) at rest and immediately after strenuous exercise, platelet adhesiveness and aggregability were decreased by training, whereas they were unchanged in the control group; and (3) deconditioning reversed the training effects on resting and postexercise platelet adhesiveness and aggregability back to the pretraining state. These results suggest that platelet adhesiveness and aggregability may be depressed by exercise training but be reversed back to the pretraining state after deconditioning.

Impedance and wave reflection in arterial system: simulation with geometrically tapered T-tubes

The aortic input impedance is simulated by an asymmetric T-tube model loaded with complex loads. A geometric tapering is incorporated to represent the vasculature, assuming a triangular distribution of the wave transmission paths. Parametric analyses using physiological data demonstrate that the predicted impedance and reflection coefficient spectrum (RCS) closely mimic the experimental data. The simulation also reveals several significant features. As diameter tapering can minimise the presence and influence of wave reflections, the impedance modulus stays relatively constant with two distinct minima. The frequency of first minimum of impedance modulus is evidence of the tube elasticity and load compliance in the lower extremity, and the frequency of second minimum is evidence of those in the upper extremity. The high-frequency portion of the impedance modulus is affected by the tube elasticity, but not by the load compliance. The impedance spectrum at higher frequencies shows no notable fluctuations corresponding to a decrease in blood or wall viscosity. Furthermore, the low-frequency range in RCS is dominated by the longer lower body tube, and the high-frequency range by the shorter upper body tube. This geometrically tapered T-tube is considered a more natural model for the description of the systemic arterial system.