Prognostic value of preoperative radiographic perinephric fat features in renal cell carcinoma patients undergoing surgery

BACKGROUND

We aimed to assess the prognostic importance of perinephric fat features in images of patients with non-metastatic renal cell carcinoma (RCC) undergoing surgery.

METHODS

We enrolled RCC patients who underwent surgical treatment between 2011 and 2019. Two characteristics, including perinephric fat thickness and perinephric fat stranding, were evaluated using preoperative computed tomography or magnetic resonance images. The association between perinephric fat characteristics and disease progression was examined by Kaplan-Meier survival analysis and Cox regression model.

RESULTS

In a multivariate Cox proportional hazards model adjusting for tumor stage, intratumoral necrosis, and neutrophil-to-lymphocyte ratio, we found that patients in the thin perinephric fat group (<1 cm) had a poorer progression-free survival (PFS) compared to the thick perinephric fat group (≥1 cm) (HR 2.8; 95% CI 1.175-6.674, p = 0.02). Additionally, the fat stranding group had a poorer PFS than the non-stranding group (HR 3.852; 95% CI 1.082-13.704, p = 0.037). The non-stranding with thick perinephric fat group exhibits the highest cumulative PFS while the stranding with thin perinephric fat group has the lowest cumulative PFS. In receiver operating characteristic curve analysis, combing these two perinephric fat characteristics with tumor stage can achieve a better discriminatory power than tumor stage alone.

CONCLUSIONS

Our study indicates that the evaluation of image-based perinephric fat features is a simple, straightforward, reproducible tool for predicting RCC prognosis and may assist in preoperative risk stratification.

Evaluation of oxytetracycline leaching from pregelatinized starch-coated medicated fish feed

The rapid growth and intensification of aquaculture industries have led to an increased use of antibiotics. Consequently, growing concerns have mounted over the environmental contamination of these drugs from medicated feeds and the risk that this poses for antimicrobial resistance. To circumvent environmental leaching, farmers topcoat medicated feeds with oil; however, this only partially addresses the issue. This study investigated the potential of food-grade pregelatinized corn starch (PGS) as a second top-coating agent to reduce oxytetracycline (OTC) leaching from the hand-mixed medicated feed. We immersed top-coated medicated feeds for different periods of time and measured the concentration of OTC in the water to determine leaching. We found a significantly lower level of OTC in water samples collected from the PGS-coated medicated feed compared to the non-PGS-coated medicated feed, with concentrations of OTC approximately 4 and 2.6 times the latter after 5 min and 2 h of water immersion, respectively. We also fed PGS-coated antibiotic feed to jade perch to determine if fish accepted the top-coating and whether they absorbed the OTC. Results from a feeding trial suggested no difference in palatability between PGS and non-PGS-coated medicated feed. We also found that muscle tissue from fish fed with the aforementioned diets had similar levels of OTC concentrations, suggesting that PGS coating does not alter the gastrointestinal absorption of this medication. From our experiment, we conclude that PGS is potentially a new top-coating agent to reduce leaching in hand-mixed OTC medicated feed.

Gross hematuria as the presentation of ureteral paraganglioma: a case report and literature review

BACKGROUND

Paraganglioma of genitourinary tract is uncommon, and origin from ureter is even rarer. We aim to present a case of paraganglioma from ureter in a 48-year-old female patient, who presented with gross hematuria.

CASE PRESENTATION

We present a 48-year-old female who complained of gross hematuria for one week. A left ureteral tumor was found by image study. However, hypertension was unexpectedly recorded during diagnostic ureteroscopy survey. Due to persisted gross hematuria and bladder tamponade, she underwent left nephroureterectomy with bladder cuff resection. Blood pressure surged again when the tumor was surgically approached. Ureteral paraganglioma was confirmed according to pathological report. After the surgery, the patient recovered well, and no more gross hematuria was noted. She is now under regular follow-up at our outpatient clinic.

CONCLUSION

Ureteral paraganglioma should be kept in mind not only when blood pressure fluctuates during operation, but also before we manipulate the ureteral tumor when gross hematuria is the only sign. Whenever the presumption of paraganglioma is raised, laboratory evaluation and anatomical or even functional imaging should be considered. The concomitant anesthesia consultation before the surgery should not be deferred, either.

Pre‑existing renal insufficiency synchronous with high preoperative neutrophil‑to‑lymphocyte ratio as a risk factor of intravesical recurrence in patients with pure upper tract urothelial carcinoma after radical nephroureterectomy

The present study aimed to evaluate the influence of pre-treatment neutrophil-to-lymphocyte ratio (NLR) on bladder recurrence in patients with impaired renal function following radical nephrouretectomy (RNU) to treat pure upper tract urothelial carcinoma (UTUC). Retrospective data of 362 patients with pure UTUC who underwent RNU between 2008 and 2019 were analyzed. Kaplan-Meier analyses were performed to evaluate the association of preoperative NLR and estimation of the glomerular filtration rate (eGFR) with intravesical recurrence-free survival (IVRF). Furthermore, multivariate analyses were conducted to determine independent factors for predicting IVRF. In the retrospective cohort study of 362 patients, 103 patients (28%) had intravesical recurrence in a median follow-up of 50.1 months; among those, 85 (83%) developed bladder recurrence within two years after RNU. The Kaplan-Meier analysis indicated that patients exhibiting lower eGFR and higher NLR showed significantly poor IVRF rates (P=0.044). The simultaneous presence of eGFR <45 and NLR >3.8 was an independent factor for the shorter IVRF time in multivariate analysis with Cox's proportional hazards model. Most intravesical recurrences occurred within two years after RNU, particularly in pre-existing poor eGFR patients with preoperative high NLR. Moreover, pre-existing moderate to severe CKD synchronous with pre-operative NLR >3.8 was demonstrated as an independent factor for subsequent bladder recurrence in patients with pure UTUC following RNU. Therefore, such high-risk patients ought to be provided with close bladder monitoring during the follow-up.

Industrial enzymes-producing marine bacteria from marine resources

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Lipase is the most dominant industrial enzyme produced by cultivated marine bacteria.

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Genetic variation determines the yield of enzyme production.

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Proteobacteria (Vibrio spp.) is the main producer of industrial enzymes.

Industrial enzymes are important for various biotechnological applications. Currently, the diversity of industrial enzymes-producing marine bacteria from Malaysia remains mostly unknown. This study investigated the diversity of industrial enzyme-producing marine bacteria from culture collections at the Institute of Marine Biotechnology, Universiti Malaysia Terengganu. Out of 200 bacterial isolates revived, 163 bacteria isolate were successfully growth. Marine bacteria produced enzymes with total scoring higher than four were selected for molecular identification using 16S rDNA. About 161 bacteria isolate secreted amylase (68.7 %), lipase (88.3 %) and protease (68.7 %). The phylogenetic analysis led to the identification of three major phyla, namely Proteobacteria, Firmicutes and Bacteroidetes. These phyla were differentiated into nine genera consisted of Bacillus, Chryseomicrobium, Photobacterium, Pseudoalteromonas, Ruegeria, Shewanella, Solibacillus, Tenacibaculum and Vibrio. Genetic variation was more likely to occur within similar marine bacteria species. The microbial community was found to affect the production of industrial enzymes and the diversity of marine bacteria.

Abstract P5-13-03: The use of a behavior-modification clinical solution application to improve breast cancer survivors' accountability and health outcomes

Background: Studies have demonstrated that obesity increases the risk of breast cancer recurrence and death in survivors but only 34% of breast cancer survivors engage in the recommended level of physical activity. This low percentage is related to a lack of accountability and motivation. We hypothesize that using a mobile application (app) incorporating the concept of cognitive-behavioral therapy and dietary and physical activity recommendations will improve breast cancer survivors' accountability and help them reach their personalized health goals; specifically with diet and exercise. Methods: We have created an app, METHODIST HOSPITAL CANCER HEALTH APPLICATION (MOCHA) for the purpose of patient self-reinforcement through the daily accounting of activity and nutrition as well as group feedback and direct interaction with clinical dietician. To test the MOCHA app's feasibility, we enrolled 33 breast cancer survivors with a body mass index (BMI) over 25 who were at least 6 months post active treatment (surgery, chemotherapy, or radiation) for a 4 week feasibility trial. During these 4 weeks, the users used the app to track wellness (mood, sleep or pain), diet (calorie intake) and exercise (walking or steps). Our primary objective was to demonstrate adherence, defined as the number of days recorded on MOCHA during week 2 and 3 of the 4 week study period (14 days). A registered dietitian assigned personalized goals for each user and monitored their usage of the app and followed the progress of their goals. Additionally, the dietitian sent daily push notifications to encourage the user to stay on track. Results: Our results suggests a correlation between utilization of the app and achievement of the goals of weight loss and increased motivation to exercise. The average number of daily uses of the app was approximately 3.76 (0-12) and 50% of enrolled users lost average of 2.14 lbs (0-6lbs) weight during this short 4 week study; preliminary correlation analysis suggest a correlation coefficient of -0.42 between these two variables. This is noteworthy as traditionally we would expect weight increase in this group of users. Our secondary objective was to determine MOCHA's usability using System Usability Scale (SUS) scale. Our average score on the SUS scale is 77%, which is above average. Lastly, users have stated that access to the dietitian in the app improves their food choices and accountability. Conclusion: This study provides essential data that emphasizes the importance of using technology to improve patients' goal adherence by providing real-time feedback and accountability with their healthcare team. Most health mobile apps focus on data acquisition but without the engagement of the health care team, this aspect differentiates MOCHA from the other apps. Our future directions will focus on using our MOCHA app in breast cancer survivors in a long term behavior modification study.

Citation Format: Stubbins RE, Cheng TH, Yu X, Puppala M, Chen S, Valdivia Y Alvarado M, Niravath PA, Chang JC, Wong ST, Patel TA. The use of a behavior-modification clinical solution application to improve breast cancer survivors' accountability and health outcomes [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 P5-13-03.

Epidemic reemergence in adaptive complex networks

The dynamic nature of a system gives rise to dynamical features of epidemic spreading, such as oscillation and bistability. In this paper, by studying the epidemic spreading in growing networks, in which susceptible nodes may adaptively break the connections with infected ones yet avoid being isolated, we reveal a phenomenon, epidemic reemergence, where the number of infected nodes is incubated at a low level for a long time and then erupts for a short time. The process may repeat several times before the infection finally vanishes. Simulation results show that all three factors, namely the network growth, the connection breaking, and the isolation avoidance, are necessary for epidemic reemergence to happen. We present a simple theoretical analysis to explain the process of reemergence in detail. Our study may offer some useful insights, helping explain the phenomenon of repeated epidemic explosions.

Bound states of dispersion-managed solitons in a fiber laser at near zero dispersion

We report on the observation of various bound states of dispersion-managed (DM) solitons in a passively mode-locked erbium-doped fiber ring laser at near zero net cavity group velocity dispersion (GVD). The generated DM solitons are characterized by their Gaussian-like spectral profile with no sidebands, which is distinct from those of the conventional solitons generated in fiber lasers with large net negative cavity GVD, of the parabolic pulses generated in fiber lasers with positive cavity GVD and negligible gain saturation and bandwidth limiting, and of the gain-guided solitons generated in fiber lasers with large positive cavity GVD. Furthermore, bound states of DM solitons with fixed soliton separations are also observed. We show that these bound solitons can function as a unit to form bound states themselves. Numerical simulations verified our experimental observations.

Dynamics of gain-guided solitons in an all-normal-dispersion fiber laser

We report experimental and numerical results on the dynamics of gain-guided solitons in a passively mode-locked erbium-doped fiber laser made of purely normal dispersion fibers. We show that formation of the soliton in the laser is a result of mutual interaction and balance among the cavity transmission, fiber Kerr nonlinearity, gain saturation, and filtering over one cavity round trip.

Generation of multiple gain-guided solitons in a fiber laser

We report the experimental observation of multiple gain-guided solitons in an erbium-doped fiber laser made of all normal-dispersion fibers. Numerical simulations show that, in the case of a narrow gain bandwidth, under the action of the cavity pulse peak clamping effect multiple gain-guided solitons can indeed be formed in a laser.

Gain-guided solitons in dispersion-managed fiber lasers with large net cavity dispersion

Gain-guided solitons are experimentally observed in dispersion-managed fiber lasers with large net positive group-velocity dispersion. It is shown that formation of the soliton is a robust feature of the lasers. Numerical simulations also confirmed the experimental results.

Supplemention with tetrahydrobiopterin suppresses the development of hypertension in spontaneously hypertensive rats

It has been suggested that tetrahydrobiopterin (H(4)B), a cofactor of NO synthase, can reverse endothelial dysfunction caused by cardiovascular diseases, including atherosclerosis, coronary artery disease, and hypertension. Moreover, an impairment of H(4)B biosynthesis in spontaneously hypertensive rats (SHR) was observed. Thus, we hypothesized that the defect of the H(4)B synthesis system may play an important role in the development of hypertension in SHR. In the present study H(4)B (10 mg/kg per day IP) was used to treat SHR and Wistar-Kyoto rats (WKY) from the age of 5 through 16 weeks. Results demonstrated that chronic treatment with H(4)B significantly improved the impaired vascular responses to acetylcholine and suppressed the development of hypertension in SHR but did not affect WKY. The increase of inducible NO synthase expression, nitrotyrosine immunostaining, NO production, and superoxide anion formation in adult SHR were also significantly suppressed by chronic treatment with H(4)B. In contrast, H(4)B had no effect on WKY. In conclusion, this study demonstrated that H(4)B significantly attenuated the development of hypertension in SHR. The antihypertensive effect of H(4)B might be mediated through its direct antioxidant activity and/or decreasing oxygen free radical production from NO synthase, thereby reducing inducible NO synthase expression and peroxynitrite formation. Thus, the present study proposed that supplementation with H(4)B might be beneficial in preventing pathological conditions such as essential hypertension.

Reactive oxygen species mediate cyclic strain-induced endothelin-1 gene expression via Ras/Raf/extracellular signal-regulated kinase pathway in endothelial cells

Endothelin-1 (Et-1) is a peptide synthesized by endothelial cells (ECs) both in culture and in vivo. Cyclic strain induces gene expression of Et-1, however, the molecular mechanisms remain unclear. Since cyclic strain induces a sustained increase in intracellular reactive oxygen species (ROS), we hypothesized that the ROS could be a modulator in strain-induced Et-1 gene expression. Human umbilical vein ECs (HUVECs) subjected to cyclic strain had increased Et-1 secretion. Pretreatment of HUVECs with antioxidants, catalase (300 U/ml) or 1,3-dimethyl-2-thiourea (DMTU, 0.1 mm), abolished the strain-induced Et-1 release. ECs strained for 6 h had elevated Et-1 mRNA levels. In contrast, ECs treated with catalase or DMTU did not have increase Et-1 mRNA levels stimulated by cyclic strain. Bovine aortic ECs (BAECs) transfected with fusion plasmid containing Et-1 5'-flanking sequence (4.4 kb) and chloramphenicol acetyltransferase reporter gene produced a maximal Et-1 promoter activity after undergoing strain for 6 h, whereas pretreatment with catalase decreased this activity. BAECs cotransfected with a dominant negative mutant of Ras (RasN17), Raf-1 (Raf301), or catalytically inactive mutant of extracellular signal-regulated kinase (mERK2) had inhibited strain-induced Et-1 promoter activity, indicating the Ras/Raf/ERK pathway was involved; moreover, ERK phosphorylation was induced in ECs which were strained. This strain-activated ERK phosphorylation was attenuated in the presence of catalase. Functional analysis of the Et-1 promoter with site-directed mutagenesis indicates that the activator protein-1 (AP-1) binding site had to be within 143 base-pairs upstream of transcription initiation site for strain-induced promoter activity. Pretreatment of ECs with catalase also decreased the strain-induced promoter activity in the minimal construct (-143 bp). Our data demonstrate that strain-induced Et-1 gene expression is modulated by ROS via Ras/Raf/ERK signaling pathway, and indicate the responsiveness of the AP-1 binding site for strain-induced Et-1 expression.

Inhibitory effect of endothelin-1 on the isoproterenol-induced chloride current in human cardiac myocytes

It is still controversial whether the cAMP-activated Cl(-) current (I(Cl,cAMP)) is expressed in human cardiomyocytes. The whole-cell configuration of the voltage-clamp technique was used to examine in detail the I(Cl,cAMP) in single human atrial and ventricular myocytes. Human cardiomyocytes were enzymatically isolated from atrial or ventricular specimens obtained from open-heart surgery or cardiac transplantation, respectively. Isoproterenol (1 microM) or forskolin (10 microM) was used to activate the cAMP second-messenger system. The isoproterenol- or forskolin-induced Cl(-) current was elicited in 12 of 54 atrial myocytes but was completely absent from ventricular myocytes. The isoproterenol-induced Cl(-) current in atrial myocytes was time-independent and had a reversal potential close to zero. Endothelin-1 (30 nM) inhibited the isoproterenol-induced Cl(-) current by 75+/-6% (n=4). This inhibitory effect of endothelin-1 was attenuated by pretreating atrial myocytes with the endothelin ET(A) receptor antagonist, BQ485, but not with the ET(B) receptor antagonist, BQ-788. The results provide evidence that the I(Cl,cAMP) exists in human atria, but not ventricle, and is inhibited by endothelin-1.

Reactive oxygen species modulate angiotensin II-induced beta-myosin heavy chain gene expression via Ras/Raf/extracellular signal-regulated kinase pathway in neonatal rat cardiomyocytes

Angiotensin II (Ang II) causes cardiomyocytes hypertrophy. Cardiac beta-myosin heavy chain (beta-MyHC) gene expression can be altered by Ang II. The molecular mechanisms are not completely known. Reactive oxygen species (ROS) are involved in signal transduction pathways of Ang II. However, the role of ROS on Ang II-induced beta-MyHC gene expression remains unclear. Here we found that Ang II increased beta-MyHC promoter activity and it was blocked by Ang II type 1 receptor antagonist losartan. Ang II dose-dependently increased the intracellular ROS. Cardiomyocytes cotransfected with a dominant negative mutant of Ras (RasN17), Raf-1 (Raf301), or a catalytically inactive mutant of extracellular signal regulated kinase (mERK2) inhibited Ang II-induced beta-MyHC promoter activity, indicating Ras/Raf/ERK pathway was involved. Antioxidants such as catalase or N-acetyl-cysteine decreased Ang II-activated ERK phosphorylation and inhibited Ang II-induced beta-MyHC promoter activity. These data indicate that Ang II increases beta-MyHC gene expression in part via the generation of ROS.

Prokinetic agents increase plasma albumin in hypoalbuminemic chronic dialysis patients with delayed gastric emptying

Hypoalbuminemia is a surrogate of malnutrition in patients with end-stage renal disease undergoing chronic dialysis and commonly improves with prescription of adequate nutrition and dialysis. Nevertheless, some patients remain hypoalbuminemic for poorly understood reasons. We tested the hypotheses that chronic dialysis patients who remain hypoalbuminemic despite prescription of adequate nutrition and dialysis (1) have delayed gastric emptying, and (2) that prokinetic agents will increase plasma albumin (P(alb)) levels in patients with delayed gastric emptying. We retrospectively identified 99 of 343 hemodialysis and peritoneal dialysis patients with hypoalbuminuria (P(alb) < 3.5 mg/dL) and studied those who did not (hypoalbuminemic, n =15) and did (normoalbuminemic, n = 15) increase their P(alb) levels over the subsequent 6 months and met inclusion and exclusion criteria. Gastrointestinal symptom scores determined by an administered questionnaire were not different in hypoalbuminemic and normoalbuminemic patients. Conversely, the half-time (T(1/2)) for radionuclide gastric emptying was longer in hypoalbuminemic than normoalbuminemic patients (74.5 +/- 7.4 versus 46.7 +/- 4.6 minutes; P < 0.004). Hypoalbuminemic patients were prescribed prokinetics and followed prospectively for 6 months, during which time gastric T(1/2) decreased to 53.9 +/- 3.3 minutes (P < 0.01 versus initial) and P(alb) increased from 3.1 +/- 0.2 to 3.5 +/- 0.2 mg/dL (P < 0.004). The net increase in P(alb) level correlated with the net decrease in gastric T(1/2) (r(2) = 0.4; P < 0.04) by linear regression. The data show that some persistently hypoalbuminemic chronic dialysis patients have poor gastric emptying and increase their P(alb) levels in response to prokinetic agents.

Establishment of transcriptional silencing in the absence of DNA replication

Transcriptional repression of the silent mating-type loci in Saccharomyces cerevisiae requires a cell cycle-dependent establishment step that is commonly assumed to involve DNA replication. Using site-specific recombination, we created a nonreplicating DNA ring in vivo to test directly the role of replication in establishment of silencing. Sir1 was tethered to the ring following excision from the chromosome to activate a dormant silencer. We show here that silencing can be established in DNA that does not replicate. The silenced ring adopted structural features characteristic of bona fide silent chromatin, including an altered level of DNA supercoiling and reduced histone acetylation. In addition, the process required silencing factors Sir2, Sir3, and Sir4 and progression between early S and M phases of the cell cycle. The results indicate that passage of a replication fork is not the cell-cycle event required for establishment of silencing in yeast.

Controlling gene expression in yeast by inducible site-specific recombination

An intron module was developed for Saccharomyces cerevisiae that imparts conditional gene regulation. The kanMX marker, flanked by loxP sites for the Cre recombinase, was embedded within the ACT1 intron and the resulting module was targeted to specific genes by PCR-mediated gene disruption. Initially, recipient genes were inactivated because the loxP-kanMX-loxP cassette prevented formation of mature transcripts. However, expression was restored by Cre-mediated site-specific recombination, which excised the loxP-kanMX-loxP cassette to generate a functional intron that contained a single loxP site. Cre recombinase activity was controlled at the transcriptional level by a GAL1::CRE expression vector or at the enzymatic level by fusing the protein to the hormone-dependent regulatory domain of the estrogen receptor. Negative selection against leaky pre-excision events was achieved by growing cells in modified minimal media that contained geneticin (G418). Advantages of this gene regulation technique, which we term the conditional knock-out approach, are that (i) modified genes are completely inactivated prior to induction, (ii) modified genes are induced rapidly to expression levels that compare to their unmodified counterparts, and (iii) it is easy to use and generally applicable.

Yeast heterochromatin is a dynamic structure that requires silencers continuously

Transcriptional silencing of the HM loci in yeast requires cis-acting elements, termed silencers, that function during S-phase passage to establish the silent state. To study the role of the regulatory elements in maintenance of repression, site-specific recombination was used to uncouple preassembled silent chromatin fragments from silencers. DNA rings excised from HMR were initially silent but ultimately reactivated, even in G(1)- or G(2)/M-arrested cells. In contrast, DNA rings bearing HML-derived sequence were stably repressed due to the presence of a protosilencing element. These data show that silencers (or protosilencers) are required continuously for maintenance of silent chromatin. Reactivation of unstably repressed rings was blocked by overexpression of silencing proteins Sir3p and Sir4p, and chromatin immunoprecipitation studies showed that overexpressed Sir3p was incorporated into silent chromatin. Importantly, the protein was incorporated even when expressed outside of S phase, during G(1) arrest. That silencing factors can associate with and stabilize preassembled silent chromatin in non-S-phase cells demonstrates that heterochromatin in yeast is dynamic.

Reactive oxygen species modulate endothelin-I-induced c-fos gene expression in cardiomyocytes

OBJECTIVES

Recent evidence indicates that reactive oxygen species (ROS) may act as second messengers in receptor-mediated signaling pathways. The possible role of ROS during Et-1 stimulation in cardiomyocytes was therefore investigated.

METHODS

Intracellular ROS levels were measured with fluorescence probe 2',7'-dichlorofluorescin diacetate by confocal microscopy in cultured neonatal rat cardiomyocytes. The ROS-inducible c-fos expression was analyzed by Northern blotting and promoter activity.

RESULTS

Et-1 applied to cardiomyocytes dose-dependently increased intracellular ROS levels. The increase of ROS levels was attenuated by pretreating cardiomyocytes with Et-A receptor antagonist-BQ485, but not with Et-B receptor antagonist. Cardiomyocytes pretreated with catalase or an antioxidant N-acetylcysteine (NAC) reduced Et-1-induced ROS levels. Et-1 or H2O2 treatment of cardiomyocytes rapidly induced the expression of an immediate early gene c-fos. Et-1-treated cardiomyocytes enhanced the c-fos gene expression as revealed by functional analysis using a reporter gene construct containing c-fos promoter region (-2.25 kb) and reporter gene chloramphenicol acetyltransferase. The induction of mRNA levels and the promoter activities of c-fos gene by Et-1 or H2O2 were abolished by pretreating cardiomyocytes with catalase or NAC. Cells transiently transfected with the dominant positive mutant of p21ras (RasL61) led to a significant increase in intracellular ROS. Concomitantly, the mRNA levels and the promoter activities of c-fos were also induced. In contrast, cells transfected with the dominant negative mutant of Ras (RasN17) inhibited Et-1-induced ROS. Consistently, the increase of c-fos mRNA levels and promoter activities by Et-1 were also inhibited.

CONCLUSIONS

These findings clearly indicate that Et-1 treatment to cardiomyocytes can induce ROS via Ras pathway and the increased ROS are involved in the increase of c-fos expression. Our studies thus emphasize the importance of ROS as second messengers in Et-1-induced responses on cardiomyocytes.

Isolation of selected chromatin fragments from yeast by site-specific recombination in vivo

A burgeoning interest in the role of chromatin structure in a wide variety of chromosome functions has established a need for methods to obtain chromatin in its native form. Here we describe a simple and efficient method for biochemical isolation of selected chromatin fragments from yeast chromosomes. The approach involves three steps. First, site-specific recombination in vivo is used to excise a chromosomal domain of interest in the form of a small extrachromosomal ring. Second, whole cell lysate is prepared from cultures in which recombination has been induced. Third, differential centrifugation is used to separate excised chromatin rings from chromosomes and other cellular debris. Using this methodology, we show that rings containing the transcriptionally repressed HMR mating-type locus can be formed and isolated in high yield. Furthermore, we show that the isolation procedure results in significant enrichment of recombinant rings. Finally, we show that the nucleosomal organization of the recombined material is not altered during isolation.

Persistence of an alternate chromatin structure at silenced loci in the absence of silencers

In Saccharomyces cerevisiae, genes placed near telomeres or the silent HML and HMR mating-type loci are transcriptionally repressed by a heterochromatin-like structure. We have generated nonreplicating DNA rings by recombination in vivo to examine the role of chromosomal context on transcriptional repression. Specifically, recombination at HMR was used to produce rings that lacked the E and I silencers. An altered level of DNA supercoiling was observed in these rings but not in comparable rings from derepressed loci. Our results indicate that a repressive chromatin structure persists in an extrachromosomal environment immediately following removal of the cis-acting control elements. Examination of both chromatin footprints and DNA sequence dependence revealed that changes in nucleosome number could account for the topology shifts. Upon continued cell growth, the differences in supercoiling were lost and transcriptional competence was restored. These results show that silencers are required for sustained persistence of repressive chromatin structure, even in the absence of DNA replication.

Modulation of CFTR chloride channels by calyculin A and genistein

Modulation of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel by calyculin A and genistein was studied in Hi-5 insect cells infected with baculovirus containing the wild-type CFTR cDNA. In cell-attached patches, CFTR channel activity was not observed until stimulated by forskolin in 90% of the cells, suggesting a low level of basal adenosine 3',5'-cyclic monophosphate activity. Calyculin A, a specific inhibitor of phosphatases 1 and 2A, increased forskolin-induced CFTR activity by 17.2-fold. CFTR channel currents did not deactivate completely after forskolin was withdrawn in the continued presence of calyculin A. Genistein enhanced forskolin-induced CFTR activity by 44.9-fold but could neither activate the CFTR by itself nor prevent complete deactivation on removal of forskolin. Genistein together with calyculin A could adequately prevent deactivation of CFTR currents. Noise analysis of the macroscopic CFTR currents revealed significant differences in the mean current-variance-relationship and the corner frequency of the noise spectra between currents activated by forskolin plus genistein and those activated by forskolin plus calyculin A. Furthermore, genistein enhanced CFTR activity induced by saturating concentrations of forskolin and calyculin A. Our results suggest that genistein and calyculin A modulate the CFTR by different mechanisms and that genistein might inhibit calyculin A-insensitive dephosphorylation of the CFTR.

Detection of iron(III) chelate separated by reversed-phase high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method for the analysis of iron(III)-N, N'-trimethylenebis[2-(2-hydroxyl-5-ethyl-phenyl)glycine] (Fe(TM-5-ethyl-PHPG)-), which is potentially used as effective hepatobiliary magnetic resonance imaging (MRI) contrast agent, has been developed in this study. The effect of mobile phase, such as the varied pH values, ion-pairing agents and concentration of the ion-pairing agent on the capacity factor of the diastereomers and free ligand, were investigated to improve the separation and peak shape. HPLC in connection with a ion exchange column and a UV/VIS detector can be used to determine metal ion dissociated from this complex. This protocol can be successfully used in the quality assay of the synthesized potential MRI contrast agent of [Fe(TM-5-ethyl-PHPG)-].

Comparison of calcium-current in isolated atrial myocytes from failing and nonfailing human hearts

To identify possible alterations of the L-type calcium currents (I(Ca),L) in cardiomyopathy, I(Ca),L were recorded in atrial myocytes dissociated from the nonfailing heart (NF) of patients undergoing corrective open-heart surgery and explanted failing heart (FH) of patients with dilated cardiomyopathy undergoing heart transplantation. The patch-clamp technique was applied in the single-electrode whole-cell mode. The electrophysiological properties of I(Ca),L, including cell capacitance and current density, were similar in atrial myocytes from both groups of patients. Further to identify possible alterations of the myocardial beta-adrenergic pathway in cardiomyopathy, we examined the effects of isoproterenol, forskolin, 8-Br-cAMP and IBMX on I(Ca),L in both groups of atrial myocytes. Perfusion of isoproterenol (1 microM) significantly increased the peak I(Ca),L by 515 +/- 44% in 6 atrial myocytes from NF but increased only by 135 +/- 25% in 27 atrial myocytes from FH. However, forskolin (1 microM) or 8-Br-cAMP (0.1 mM) increased the peak I(Ca),L to a similar extent in atrial myocytes from NF and FH. IBMX (20 microM) also induced a comparable increase in the peak I(Ca),L by 213 +/- 31% (n = 5) and 207 +/- 59% (n = 4) in atrial myocytes from NF and FH, respectively. The above findings suggest that in atrial myocytes obtained from FH the beta-adrenoceptor numbers might be decreased but no impairment of the signal transduction cascade occurred beyond the GTP binding proteins level.

Effects of endothelin 1 on calcium and sodium currents in isolated human cardiac myocytes

We have used the whole-cell voltage-clamp technique to study the effects of endothelin 1 (ET-1, 10 nM) on L-type Ca2+ currents and voltage-dependent Na+ inward currents in human cardiac cells. Myocytes were enzymatically isolated from atrial specimens obtained during open-heart surgery and from human ventricular tissues of explanted hearts. Extracellular application of ET-1 decreased the peak amplitude of Ca2+ currents by 26 +/- 6% (n = 13) in atrial myocytes and by 19 +/- 3% (n = 8) in ventricular myocytes. In three atrial cells, treatment with 1 microM BQ123 prevented the decrease in Ca2+ currents induced by ET-1. When GTP (0.2 mM) was added to the dialyzing pipette solution, ET-1 still caused a small decline by 12 +/- 5% (n = 16), in peak Ca2+ currents, in atrial myocytes. When Ca2+ currents were increased (+210 +/- 19%) by a beta-adrenoceptor agonist (0.1 microM isoproterenol) or by the phosphodiesterase inhibitor isobutylmethylxanthine (10 microM), ET-1 reduced Ca2+ currents by 35 +/- 6% (n = 4) and 30 +/- 4% (n = 5), respectively. In human ventricular myocytes in the presence of 1 microM isoproterenol, which increased the peak Ca2+ currents by 150 +/- 30%, ET-1 also induced a drastic reduction in Ca2+ currents, by 40 +/- 11% (n = 5). The tetrodotoxin-sensitive Na+ currents measured in the presence of 5 mM [Na]o were significantly enhanced (+28 +/- 7%) by ET-1 in five atrial myocytes. The stimulatory effect of ET-1 on Na+ currents was partially reversible. The present findings in human cardiac cells show that ET-1 did not enhance the Ca2+ currents in the absence or presence of internal GTP. The positive inotropic actions induced by ET-1 in human heart may be mediated mainly by signal-transduction pathways other than the G-protein-adenylyl cyclase-cAMP system.

Antiplatelet constituents of formosan Rubia akane

A known steroid, in addition to triterpenoids, anthraquinones, naphthalenes and a new anthraquinone glycoside, xanthopurpurin 3-O-beta-D-glucoside, were isolated from the roots of Rubia akane grown in Taiwan. Mollugin, a naphthohydroquinone, showed strong inhibition of arachidonic acid (AA)-induced and collagen-induced platelet aggregation. In contrast, 2-methyl-1,3,6-trihydroxyl-9,10-anthraquinone, xanthopurpurin 3-O-beta-D-glucoside, and xanthopurpurin showed mainly strong inhibition of collagen-induced platelet aggregation.

Gamma-pyrone compounds as potential anti-cancer drugs

The gamma-pyrones, artomunoxanthotrione epoxide, cyclocommunol, cyclomulberrin, and cyclocommunin exhibited potent inhibition of human PLC/PRF/5 and KB cells in-vitro. Dihydroisocycloartomunin showed significant and potent inhibition of human PLC/PRF/5 and KB cells in-vitro, respectively. Cyclomorusin, dihydrocycloartomunin and artomunoxanthone showed significant inhibition of KB cells in-vitro. Based on the above finding and the reported antileukaemic activity of xanthone psorospermin, a series of natural gamma-pyrones was prepared and the inhibition of human PLC/PRF/5 and KB cells in-vitro was measured. Structure-activity analysis indicated the epoxide group substituted at 3-hydroxyl and 2,6-; 3,6-; and 3,5-dihydroxyl xanthone enhanced the anti-tumour activity. The epoxide group substituted at the 6-hydroxyl group of 1,6-dihydroxyxanthone did not show anti-tumour activity.

Testicular torsion in children: scintigraphic assessment

Seventy-five patients with suspected testicular torsion who had scintiscans and adequate clinical follow-up were analyzed retrospectively. The scintiscans diagnosed 12/13 cases of surgically proven missed torsion and 3/3 cases of surgically proven acute complete torsion. The scintiscans successfully distinguished all 35 cases of epididymo-orchitis, 14 cases of torsion of the appendix testes and 8 other miscellaneous conditions from testicular torsion. The incidence of testicular torsion in our patients undergoing scrotal scintigraphy was approximately 24%.

Increased skeletal:renal uptake ratio: etiology and characteristics

Twenty-four patients with increased skeletal:renal uptake ratios of 99mTc-methylene diphosphonate were studied. Increased uptake was central in metastatic prostate carcinoma, peripheral in hematologic disorders, and heterogeneous in Paget disease and fibrous dysplasia. There was no discernible redistribution of skeletal uptake in patients with renal failure. Absence of both renal and bladder activity was not observed in patients with normal renal function. An increased ratio was always abnormal and frequently indicated diffuse bone disease.

Evaluation of hepatobiliary imaging by radionuclide scintigraphy, ultrasonography, and contrast cholangiography

Cholescintigraphy, ultrasonography, and contrast cholangiography were compared in 60 patients. Among those having abdominal pain but no biliary disease or jaundice, cholescintigraphy was normal in 14/14, ultrasound in 10/13, and cholangiography in 13/14. Jaundice due to hepatocellular disease was correctly distinguished from complete biliary obstruction by cholescintigraphy in 17/17 patients and by ultrasound in 14/17. In cholelithiasis, ultrasound was abnormal in 10/12 and cholangiography in 7/9. Cholescintigraphy appeared most sensitive to active cholecystitis; only cholangiography and ultrasound visualized gallstones.

Radionuclide assessment of Gaucher's disease

Gaucher's disease involves multiple organs and may present with variable severity. The scintigraphic appearance of the reticuloendothelial system and bone are described in three patient's with Gaucher's disease. Scintigraphic abnormalities reflected the severity of organ involvement and correlated well with the patients' clinical status. Scintigraphy appears useful for the evaluation and followup of patients with Gaucher's disease.

Pulmonary actinomycosis. A report of three cases

The diagnosis of thoracic actinomycosis is readily made when the patient presents with the constellation of poor oral hygiene, pulmonary infiltrates, empyema, sinus tracts, and osteomyelitis of the ribs. However, in the absence of rib and chest wall involvement, the disease may be overlooked. Three cases of primary pulmonary actinomycosis are presented showing three different pulmonary forms of the disease and comprising (a) subacute patchy pulmonary infiltrates, (b) a cavitary lesion simulating tuberculosis, and (c) a central mass lesion simulating bronchogenic carcinoma.