bluuebunny/crossref_metadata_2025 huggingface dataset:
Dopants in Flame Synthesis of Titania
Authors: Vemury Srinivas , Pratsinis Sotiris E.
Published: October 2005

The effect of dopants on the characteristics of titania particles made by oxidation of TiCl4 in a laminar diffusion flame reactor is presented. Introduction of dopant SiCl4 inhibits the transformation of anatase to rutile, due to the formation of interstitian solid solution of SiO2 and TiO2. Silica decreases the sintering rate of titania and decreases the primary particle size, and, as a result, the specific surface area increases. Intruduction of SnCl4 enhances the transformation of anatase to rutile, due to the similar crystalline structure of SnO2 and rutile titania. However, the presence of SnO2 and rutile titania. However, the presence of SnO2 does not affect the primary particle size or the specific surface area of titania particles. Introduction of AICI3 enhances the transformation of anatase to rutile, due to the formation of excess oxygen vacancies as Al2O3 and TiO2 form a substitutional solid solution.
Silicon Nitride and Silicon Carbonitride by the Pyrolysis of Poly(methylsiladiazane)
Authors: He Jiliang , Scarlete Mihai , Harrod John F.
Published: October 2005

Poly(methylsiladiazane) (PMSDZ) is synthesized by the copolymerization of MeHSiCl2 with H2NNH2 in 1:14 molar ratio. The structure of the polymer is shown by NMR and IR spectroscopies to consist of tetraazadisilacyclohexane rings bridged by MeHSi groups. The polymer gives a mixture of silicon nitride and silicon carbonitride when heated above 1100°C under an inert atmosphere. Ceramic yields are increased relative to those obtained with the native polymer (67%) by cross‐linking with a dimethyltitanocene catalyst, or by thermal curing at 150°C (ceramic yields of 76% and 81%, respectively). The pyrolytic conversion of PMSDZ to ceramic products is studied by characterizing the solid residues by using FT‐IR and solid‐state 29Si MAS NMR spectroscopies, elemental analysis, and X‐ray powder diffraction. Thermal curing of PMSDZ at 150°C results mostly in increased cyclization of the reaction of bridging MeHSi moieties. At 300°C N‐N bond cleavage occurs rapidly with the formation of a polysilazane structure, in which the silicon is mosly coordinated as MeHSi(N)2 and MeSi(N)3 fragments. A mechanism involving the formation and reaction of silylaminyl radicals is proposed to account for these structural changes. Some methylene insertion occurs at 500°C, to form MeSi(CH2)(N)2 units. This step is critical for the incorporation of carbon into the ceramic product. At the same time Si(N)4 fragments are also generated. Between 700° and 900°C a high concentration of persistent free radicals is formed. Amorphous silicon carbonitride (SiNxCy) and Si3N4 are produced at 1100°C. Even after heating to 1500°C most of the product is still amorphous, only a small amount of crystalline α‐Si3N4 being detected by XRD.
Effect of Micmcracking on the Fracture Toughness and Fracture Surface Fractal Dimension of Lithia‐Based Glass‐Ceramics
Authors: Thompson Jeffrey Y , Anusavice Kenneth J. , Balasubramaniam Balamurali , Mecholsky John J.
Published: October 2005

The effect of thermally induced microcracks on the fracture toughness and fractal dimension of fully crystalline lithia disilicate glass‐ceramics was studied. The fracture toughness, KIC, for the nonmicrocracked lithia disilicate, 3.02 ± 0.12 MPa·m1/2, was significantly greater than the value of 1.31 ± 0.05 MPa·m1/2 for the microcracked specimens. The fractal dimensional increment, D*, was 0.24 ± 0.01 for nonmicrocracked lithia disilicate specimens compared with a value of 0.18 ± 0.01 for the microcracked specimens. The relationship between KIC and D* implies that the two materials exhibit dissimilar fracture behavior because of microstructural differences. Estimates of the characteristic length involved in the fracture process, a0, indicate that the materials have an identical fracture process at the atomic level. This apparent contradiction may be explained by the scale on which the measurements were taken. It is suggested that fractal analysis at the atomic level would yield equivalent D* values for the two different microstructures.
Intrinsic Equilibrium Constants of beta;‐Silicon Carbide Obtained from Surface Charge Data
Authors: čerović Ljiljana S. , Milonjié Slobodan K. , Kostić‐Gvozdenović Ljiljana
Published: October 2005

The surface charge behavior of β‐SiC in KNO3 electrolyte solutions is reported as a function of pH and ionic strength. The surface charge densities were obtained by potentiometric titration, and the point of zero charge of β‐SiC was determined by the batch equilibration method. The intrinsic equilibrium constants, describing association‐dissociation of surface groups, were calculated using the site‐binding model.
Dislocations in as‐Grown CVD α‐Silicon Nitride
Authors: Zhou Dashun S. , Mitchell Terence E.
Published: October 2005

CVD αSi3N4 has been studied by transmission electron microscopy, and dislocations are found to occur in as‐grown material. Two‐beam contrast analysis has been used to determine that these dislocations have Burgers vectors of (0001), 1/3(2110), and 1/3(2113). Because of their smaller Burgers vector, (0001) dislocations are dominant. Their dissciation into half partials has been observed.
High‐Temperature Behavior of Silicon Carbide Fibers in a Si‐Al‐Ca‐O‐N Ceramic Matrix
Authors: Shin Hyunho
Published: October 2005

A Nicalon SiC fiber‐reinforced Si‐Al‐Ca‐O‐N composite was fabricated by a slurry infiltration process followed by hot pressing at 1600°C. A carbon‐rich interfacial layer (∼100 nm) as well as a crystalline silicon‐rich layer (∼15 nm) was observed between the fiber and matrix. Based on this interfarcial phenomenology, the following behabior of SiC fibers in the matrix was proposed: fine SiC grains (diameter of ∼ 1.7 nm in as‐received fibers) decomposed at fiber surfaces (SiC → C + Si), followed by silicon migration into the glasshy phase of the matrix. The glassy phase was interpreted to play a key role as a silicon consumer in fostering the formation of the carbon‐rich layer. The presence of silicon implied that the oxygen activity in the matrix was low enough to avoid SiC oxidation.
Differences in susceptibility to N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine‐induced urinary bladder carcinogenesis between SD/gShi rats with spontaneous hypospermatogenesis and SD/cShi rats with spontaneous hydronephrosis
Authors: Murai Takashi , Mori Yukio , Tatematsu Kenjiro , Koide Akihiro , Hagiwara Akihiro , Makino Susumu , Mori Satoru , Wanibuchi Hideki , Fukushima Shoji
Published: October 2005

Differences in susceptibility to N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine (BBN)‐induced urinary bladder carcinogenesis between two substrains of male Sprague–Dawley rats were examined. One substrain was SD/gShi, which has spontaneous hypospermatogenesis, and the other was SD/cShi, which is a sister strain of SD/gShi, and has normal testis but spontaneous hydronephrosis. SD/gShi rats had a lower incidence of urinary bladder tumors and had lower 5‐bromo‐2′‐deoxyuridine labeling indices in the urinary bladder epithelium than SD/cShi rats when BBN was given. SD/gShi rats had significantly lower urinary concentrations of N‐butyl‐N‐(3‐carboxypropyl)nitrosamine (BCPN), which is a metabolite and proximate carcinogen of BBN. In vitro analysis also showed significantly less BCPN formation, using an S9 mix derived from the liver and kidney, in SD/gShi rats than in SD/cShi rats. BCPN formation in vitro was markedly inhibited by non‐selective cytochrome P450 (CYP) inhibitors, but not alcohol dehydrogenase inhibitor. However, analysis of CYP proteins including hepatic CYP1A1/2, 2B1/2, 2E1, and 3A2 and renal CYP2E1 and 3A2 revealed no significant variation in levels in either tissue in the groups. There were also no significant intergroup differences in the mutagenicity of carcinogens, including heterocyclic amines and N‐nitrosamines, activated by CYP1A1/2 and CYP2E1 and/or CYP2B1/2, respectively. These results suggest that SD/gShi rats are less susceptible to BBN, possibly because less BCPN is produced by CYP isoforms other than those investigated. A contribution of CYP4B1 to the strain difference is also possible. (Cancer Sci 2005; 96: 637 – 644)
Ecosystem dynamics based on plankton functional types for global ocean biogeochemistry models
Authors: Quéré Corinne Le , Harrison Sandy P. , Colin Prentice I. , Buitenhuis Erik T. , Aumont Olivier , Bopp Laurent , Claustre Hervé , Cotrim Da Cunha Leticia , Geider Richard , Giraud Xavier , Klaas Christine , Kohfeld Karen E. , Legendre Louis , Manizza Manfredi , Platt Trevor , Rivkin Richard B. , Sathyendranath Shubha , Uitz Julia , Watson Andy J. , Wolf‐Gladrow Dieter
Published: October 2005

Ecosystem processes are important determinants of the biogeochemistry of the ocean, and they can be profoundly affected by changes in climate. Ocean models currently express ecosystem processes through empirically derived parameterizations that tightly link key geochemical tracers to ocean physics. The explicit inclusion of ecosystem processes in models will permit ecological changes to be taken into account, and will allow us to address several important questions, including the causes of observed glacial–interglacial changes in atmospheric trace gases and aerosols, and how the oceanic uptake of CO2 is likely to change in the future. There is an urgent need to assess our mechanistic understanding of the environmental factors that exert control over marine ecosystems, and to represent their natural complexity based on theoretical understanding. We present a prototype design for a Dynamic Green Ocean Model (DGOM) based on the identification of (a) key plankton functional types that need to be simulated explicitly to capture important biogeochemical processes in the ocean; (b) key processes controlling the growth and mortality of these functional types and hence their interactions; and (c) sources of information necessary to parameterize each of these processes within a modeling framework. We also develop a strategy for model evaluation, based on simulation of both past and present mean state and variability, and identify potential sources of validation data for each. Finally, we present a DGOM‐based strategy for addressing key questions in ocean biogeochemistry. This paper thus presents ongoing work in ocean biogeochemical modeling, which, it is hoped will motivate international collaborations to improve our understanding of the role of the ocean in the climate system.
Phosphorus status determines biomass response to elevated CO2 in a legume : C4 grass community
Authors: Edwards Everard J. , McCaffery Stephanie , Evans John R.
Published: October 2005

Thirty‐six mesocosms, each containing a two‐species community of Trifolium repens (C3 legume) and Stenotaphrum secundatum (C4 grass), were grown in sand with three nutrient regimes, zero N low P, zero N high P and supplied N high P, under ambient (aCO2) and twice ambient CO2 (eCO2) for 15 months in two greenhouses. Aboveground annual production in the P limited mesocosms did not respond to eCO2 and was reduced by 50% relative to mesocosms with an adequate P supply, where dry‐matter production was increased by 12–24% under eCO2. The stimulation of production by eCO2 occurred throughout the year despite a clear seasonality in growth. There was no effect of eCO2 on leaf area index (LAI), which was larger under high P than low P. Live root mass at the end of the experiment was higher under eCO2 in all nutrient treatments, but the response of total belowground C (root+soil) to eCO2 depended on P treatment. Under limiting P, belowground C was not significantly changed by eCO2 (2–2.3 t belowground C ha−1). Under high P supply, both root and soil C pools increased under eCO2. Under aCO2, low P supply increased belowground C by 0.7–1 t C ha−1 above that added by the high P treatment. P is commonly limiting in Australian ecosystems and the majority of ecosystem N input is provided by biological N fixation. Consequently, the response of legumes to eCO2 is of particular importance. These results demonstrate that at low P availability, there is likely to be only a limited response of biomass production by T. repens to eCO2, which in turn may constrain any ecosystem response.
Midgut infection by tomato spotted wilt virus and vector incompetence of Frankliniella tritici
Authors: de Assis Filho F. M. , Stavisky J. , Reitz S. R. , Deom C. M. , Sherwood J. L.
Published: October 2005

Abstract:  The mechanism leading to vector competence of thrips species to transmit tomato spotted wilt virus (TSWV) is not well characterized. We investigated the interaction of TSWV and the non‐vector species Frankliniella tritici. A monoclonal antibody to the non‐structural protein (NSs) of the TSWV was used to detect TSWV replication within the thrips by immunofluorescence microscopy and enzyme‐linked immonosorbent assay (ELISA). TSWV was acquired by F. tritici, replicated and moved within the alimentary canal of F. tritici similar to a known vector of TSWV, Frankliniellaoccidentalis. However, virus was not found in the salivary glands of F. tritici, which is a prerequisite to virus transmission. Thus, movement to the salivary glands may determine vector incompetence of F. tritici.
Partial depletion of macrophages by ED7 reduces renal injury in Adriamycin nephropathy
Authors: WANG YIPING , MAHAJAN DEEPIKA , TAY YUET‐CHING , BAO SHISAN , SPICER TIM , KAIRAITIS LUKAS , RANGAN GOPALA K , HARRIS DAVID CH
Published: October 2005

Background:  Because macrophages are considered to be possible effectors of disease in Adriamycin (ADR) nephrosis, we hypothesized that depletion of macrophages might protect against the initiation of renal injury. In the present study, a monoclonal antibody (ED7) directed against CD11b/CD18 integrin, which is expressed by macrophages, was used to investigate the pathogenetic effects of macrophages in ADR nephropathy.

Methods:  Male Wistar rats were treated with ED7 antibody, starting 1 day prior to ADR (7.5 mg/kg) treatment, or 7 days post‐ADR when overt proteinuria was established.

Results:  Circulating ED7‐positive cells were reduced by approximately 30% in rats with ADR nephrosis by the ED7 antibody, while the number of macrophages in the renal cortex of ADR rats was reduced by nearly 50% with the ED7 treatment, whether administered before or after ADR. Creatinine clearance was significantly ameliorated by ED7 when commenced pre‐ADR (P < 0.05), but not when commenced post‐ADR (P = NS) in comparison to untreated ADR rats. However, proteinuria was not alleviated by either ED7 treatment. Morphometric analysis showed less glomerular sclerosis when ED7 was commenced pre‐ADR compared with ADR alone (P < 0.01), but not when commenced post‐ADR (P = NS). Tubular atrophy was reduced by ED7 when it was commenced pre‐ADR (tubular cell height and tubular diameter: P < 0.01 and P < 0.001, respectively), as was interstitial expansion (P < 0.01) compared with ADR alone. Cortical macrophage infiltration was reduced by 50% compared with ADR alone by the ED7 commenced before or after ADR. The number of cortical CD4+ T cells fell with ED7 starting pre‐ADR, but not with the ED7 treatment commencing after ADR.

Conclusion:  Partial macrophage depletion starting before but not after ADR protected both renal function and structure in this model of chronic proteinuric renal disease.
Presentation, prognosis and outcome of IgA nephropathy in Indian adults
Authors: CHACKO BOBBY , JOHN GEORGE T , NEELAKANTAN NITHYA , KORULA ANILA , BALAKRISHNAN NARASIMHAN , KIRUBAKARAN MESHACH G , JACOB CHAKKO K
Published: October 2005

Background:  IgA nephropathy (IgAN) is not well characterized in India. This retrospective study of 478 patients with IgAN was performed to clarify the presenting features, prognostic factors and the renal survival rates of the disease.

Methods:  Three hundred and forty‐seven patients who had been followed on average for 27 months after diagnosis were divided into two groups based on renal function at diagnosis. In group 1 (229 patients), the creatinine clearance estimated by the Modification of Diet in Renal Disease formula was <85 mL/min and in group 2 (118 patients) it was ≥85 mL/min.

Results:  The predominant modes of presentation were nephrotic syndrome, hypertension and renal failure. Twenty‐nine percent of patients had more than a 20% decline in renal function at the last follow up. Multivariate analyses with stepwise logistic regression identified hypertension (odds ratio (OR) 3.5), nephrotic range proteinuria (OR 3.4) and sclerosed glomeruli on biopsy (OR 4.1) to be independently associated with progression in group 1 and hypertension (OR 2.3) in group 2. Seventeen percent of patients progressed to end‐stage renal disease (ESRD). Using multivariate analysis by the Cox model, four risk factors for developing ESRD were identified: hypertension (hazard ratio (HR) 3.1); nephrotic proteinuria (HR 1.9); interstitial fibrosis (HR 2.5); and sclerosed glomeruli (HR 1.8). The renal survival rates at 1, 5 and 10 years were 84, 55 and 33%, respectively, with a median renal survival of 61 months from the time of biopsy.

Conclusion:  The relatively rapid rate of progression of IgAN in India is suggestive towards a ‘malignant’ nature of the disease in this country.
TGF‐β and TNF‐α producing effects of losartan and amlodipine on human mononuclear cell culture
Authors: KAYNAR KUBRA , ULUSOY SUKRU , OVALI ERCUMENT , VANIZOR BIRGUL , DIKMEN TAMER , GUL SEMIH
Published: October 2005

Aim:  The modulation of cytokine release, which affects adhesion of leucocytes to endothelial cells, and proliferation of peripheral blood mononuclear cells with antihypertensive drugs was explored.

Method:  In the present study, mononuclear cells were incubated with losartan and amlodipine at concentrations of 10−6, 10−5 and 10−4 mol/L for 6 h. Transforming growth factor (TGF)‐β and tumour necrosis factor (TNF)‐α levels were measured. Proliferation of mononuclear cells were assessed at the same concentrations of amlodipine and losartan with the methylthiazoletetrazolium (MTT) test.

Results:  Amlodipine was found to induce TGF‐β synthesis from mononuclear cells with increasing concentrations, while it was found to inhibit TNF‐α secretion with increasing concentrations. In contrast, losartan was found to induce TGF‐β and TNF‐α secretion with increasing concentrations.

Conclusion:  Anti‐atherosclerotic effects of amlodipine and losartan might be through increased secretion of TGF‐β from mononuclear cells. Different results at different concentrations might be due to the pharmocokinetic differences of these drugs.
Haemodialysis‐unresponsive blood pressure: Cardiovascular mortality predictor?
Authors: MOURAD ADNAN , KHOSHDEL ALIREZA , CARNEY SHANE , GILLIES ALASTAIR , JONES BERNARD , NANRA RANJIT , TREVILLIAN PAUL
Published: October 2005

Aim:  The importance of ‘conventional’ cardiovascular risk factors in haemodialysis (HD) patients has been questioned following evidence that pre‐HD blood pressure (BP) might be inversely related to mortality in contrast to post‐HD BP. To evaluate this reverse BP epidemiology in HD patients, HD‐induced BP changes were compared with aortic pulse wave velocity (PWV), an independent predictor of cardiovascular mortality.

Method:  Aortic PWV was evaluated in a limited care HD cohort, all of whom were asymptomatic of cardiovascular disease.

Results:  Of 47 limited care patients, 45% were classified as HD responsive, with a 17% fall in mean arterial pressure compared with a 6% increase in the HD‐unresponsive group. While there were no significant differences between the two groups in traditional vascular disease risk factors or interdialytic weight loss, PWV was significantly elevated in the HD‐unresponsive group (12.9 ± 2.7 compared with 10.8 ± 2.9; P < 0.05). Furthermore, there was a positive correlation between the change in BP during HD and PWV in all subjects (r = 0.500; P < 0.001 for systolic blood pressure (SBP), a correlation that also existed for diastolic blood pressure (DBP) (P < 0.01).

Conclusion:  This study suggests that patients with HD‐unresponsive BP are more likely to have vascular disease and this association between PWV and HD‐induced BP changes might partly explain the apparent paradox of pre‐ and post‐HD BP with mortality. It is proposed that a population with elevated post‐HD BP is more likely to be composed of subjects with vascular disease (overt or occult), in contrast to a group with high pre‐HD BP, which will be more heterogeneous.
Vitamin A and zinc status in patients on maintenance haemodialysis
Authors: CABRAL POLIANA COELHO , DINIZ ALCIDES DA SILVA , DE ARRUDA ILMA KRUZE GRANDE
Published: October 2005

Background:  The objective of this study was to assess the vitamin A and zinc serum levels in patients undergoing haemodialysis (HD) in the city of Recife, in the north‐eastern region of Brazil.

Methods:  The study comprised 55 patients and 28 healthy controls. The retinol and zinc serum concentrations were analysed by using high‐performance liquid chromatography (HPLC) and atomic absorption spectrophotometry, respectively.

Results:  The mean retinol serum concentration in patients (2.50 ± 0.86 µmol/L) was significantly greater (P < 0.001) than that found in controls (1.26 ± 0.86 µmol/L). The retinol serum levels in the patients were as follows: 47.3% of the patients had elevated levels (≥ 2.24 and < 3.50 µmol/L); 16.4% of the patients had serum levels ≥ 3.50 µmol/L, which indicated hypervitaminosis; and 9.1% of the patients had serum levels below the normal range (<1.05 µmol/L), a rate that among the controls was 42.9% (P < 0.01). In regard to zinc, the serum levels found in the patients (10.59 ± 3.12 µmol/L) were similar to those found in the controls (11.43 ± 2.82 µmol/L) (P > 0.05). Although 49.1% of the patients and 35.7% of the controls were classified as deficient in zinc, this difference was not statistically significant (P > 0.05).

Results:  The results identified a high prevalence of zinc deficiency in the groups studied, and point to a trend towards more elevated retinol serum levels in patients undergoing dialysis as compared with those in healthy controls.
Haemostatic partial nephrectomy using bipolar radiofrequency ablation
Authors: Pareek Gyan , Wilkinson Eric R. , Schutt David , Will James A. , Warner Thomas F. , Haemmerich Dieter , Mahvi David , Nakada Stephen Y.
Published: October 2005

OBJECTIVE

To determine whether an electrode array with a bipolar radiofrequency ablation (RFA) energy source can be used to perform a haemostatic partial nephrectomy by simultaneously ablating and coagulating renal tissue.

MATERIALS AND METHODS

Lower‐pole partial nephrectomy was performed in 12 porcine kidneys using a bipolar RFA system. Intraoperative ultrasonography was used to identify and avoid the collecting system. Tissues were positioned between opposing electrodes and tissue impedance monitored using a proprietary feedback and control algorithm. Ablation time and power, lesion width and length, and tissue thickness were recorded. The kidneys were assessed in vivo to show haemostasis of the remaining renal unit. Collecting system integrity was assessed with methylene blue injection, and the resected tissue analysed histologically.

RESULTS

Partial nephrectomies were successful in all 12 porcine kidneys; the mean nephrectomy specimen was 3.2 × 2.6 cm. The total ablation time (sem) per lesion was 211 (15) s and the mean power was 23 W. Methylene blue injection showed an intact collecting system in 11 of the 12 kidneys, and haematoxylin and eosin staining showed a mean zone of necrosis of 9 mm at the resection margin. Ultrasonography revealed flow to the remaining kidneys after RFA and the in vivo assessment of haemostasis revealed no abnormal bleeding or haemorrhage from the kidneys.

CONCLUSIONS

Applying bipolar RF energy to an electrode array can enable transmural excision of renal parenchyma in vivo in a bloodless fashion without collecting system injury.
Salvage radiotherapy for biochemical recurrence after radical prostatectomy
Authors: Terai Akito , Matsui Yoshiyuki , Yoshimura Koji , Arai Yoichi , Dodo Yoshihiro
Published: October 2005

OBJECTIVE

To evaluate the clinical outcome of salvage radiotherapy (RT) for biochemical recurrence after radical prostatectomy (RP) at our institution.

PATIENTS AND METHODS

Between March 1999 and January 2004, 37 patients had salvage RT for prostate‐specific antigen (PSA) failure after RP, including eight who had had neoadjuvant hormone therapy. After surgery, PSA was measured with ultrasensitive immunoassays. In all patients RT was delivered to the prostatic bed at a total dose of 60 Gy with a four‐field box technique.

RESULTS

The median (range) PSA level before salvage RT was 0.146 (0.06–3.216) ng/mL and RT was started at a PSA level of <0.5 ng/mL in 34 of the 37 patients (92%). With a median follow‐up of 31.9 (0–69.8), months, 11 patients (30%) had disease progression after RT and the 3‐ and 5‐year progression‐free probability was 74% and 54%, respectively. Univariate analysis showed that clinical and pathological tumour stages and PSA level before RT (>0.15 vs ≤ 0.15 ng/mL) were significant predictors of disease progression. There were no late adverse events related to RT.

CONCLUSION

Salvage RT for biochemical failure after RP at a low PSA level, using ultrasensitive immunoassays for monitoring, is a reasonably effective treatment. A relatively low radiation dose (60 Gy) seems to be effective.
Vascular damage as a risk factor for benign prostatic hyperplasia and erectile dysfunction
Authors: Berger Andreas P. , Deibl Martina , Leonhartsberger Nicolai , Bektic Jasmin , Horninger Wolfgang , Fritsche Gernot , Steiner Hannes , Pelzer Alexandre E. , Bartsch Georg , Frauscher Ferdinand
Published: October 2005

Associate Editor

Michael G. Wyllie

Editorial Board

Ian Eardley, UK

Jean Fourcroy, USA

Sidney Glina, Brazil

Julia Heiman, USA

Chris McMahon, Australia

Bob Millar, UK

Alvaro Morales, Canada

Michael Perelman, USA

Marcel Waldinger, Netherlands

OBJECTIVE

To assess benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), both considered to be associated with urogenital ageing, in ageing men in a cross‐sectional population study, comparing them with healthy controls by using symptom scores and contrast‐enhanced colour Doppler ultrasonography (CDUS).

PATIENTS, SUBJECTS AND METHODS

Transrectal CDUS and quantitative measurement of colour pixel intensity (CPI) are excellent minimally invasive techniques for assessing normal and pathological blood flow. CDUS was performed using the microbubble‐based ultrasound enhancer for evaluating prostate, bladder neck and corpus cavernosum vascularity in young healthy men, men with BPH, and men with severe vascular damage (diabetes mellitus type 2). Resistive index measurements and computer‐assisted quantification of CPI were used to objectively evaluate perfusion. The International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF) were applied to quantify the symptoms.

RESULTS

In patients with BPH, perfusion of the transition zone (TZ) of the prostate was significantly lower and the resistive index of the TZ significantly higher (both P < 0.001) than in healthy controls. The perfusion patterns of men with BPH and those who also had severe vascular damage (diabetes mellitus type 2) showed that vascularity in the latter group was lower in the prostatic TZ and the corpora cavernosa. In patients with BPH the IPSS, quality‐of‐life and IIEF scores were significantly worse than in the control group. Men with concomitant atherosclerosis had even worse symptom scores.

CONCLUSION

These results strongly support the hypothesis that age‐related impairment of blood supply to the lower urinary tract is important in the development of BPH and ED. Vascular damage may cause chronic ischaemia and thus be a contributing factor in the pathogenesis of BPH and ED.
Bladder‐health diaries: an assessment of 3‐day vs 7‐day entries
Authors: Dmochowski Roger R. , Sanders Steven W. , Appell Rodney A. , Nitti Victor W. , Davila G. Willy
Published: October 2005

OBJECTIVES

To assess the reliability of symptom reports in 3‐day vs 7‐day bladder diaries used in clinical trials of patients with overactive bladder (OAB) and to compare those results and related issues with previous reports.

MATERIALS AND METHODS

We analysed two large‐scale, randomized, phase 3 clinical trials of the use of transdermal oxybutynin for treating patients with OAB. The first trial (Trial A, 520 patients) compared three doses of transdermal oxybutynin (1.3, 2.6 and 3.9 mg/day) with placebo. Patients documented their OAB symptoms in a 7‐day diary. The second clinical study (Trial B, 361 patients) compared the efficacy of 3.9 mg/day transdermal oxybutynin with 4 mg/day extended‐release tolterodine and with placebo; this trial required symptom recording for only 3 days. The internal consistency of the data from the 7‐day trial was determined and then compared with the 3‐day trial results.

RESULTS

Patients on transdermal oxybutynin or long‐acting tolterodine for their OAB symptoms showed a clinically and statistically significant improvement, results that were documented in both 3‐day and 7‐day bladder diaries. However, compared with 7‐day symptom records, 3‐day diaries were associated with significantly better compliance with record‐keeping (P < 0.001).

CONCLUSIONS

Seven‐day diaries used in clinical trials supply accurate and reproducible data on clinical manifestations of OAB, but 3‐day diaries are equally effective and have the potential for better accuracy through increased patient convenience. Three‐day diaries may also reduce the tendency for patients to complete gaps in record‐keeping from memory.
Prospective study comparing three‐dimensional computed tomography and magnetic resonance imaging for evaluating the renal vascular anatomy in potential living renal donors
Authors: Bhatti Aftab A. , Chugtai Aamir , Haslam Philip , Talbot David , Rix David A. , Soomro Naeem A.
Published: October 2005

OBJECTIVE

To prospectively compare the accuracy of multislice spiral computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) in evaluating the renal vascular anatomy in potential living renal donors.

SUBJECTS AND METHODS

Thirty‐one donors underwent multislice spiral CTA and gadolinium‐enhanced MRA. In addition to axial images, multiplanar reconstruction and maximum intensity projections were used to display the renal vascular anatomy. Twenty‐four donors had a left laparoscopic donor nephrectomy (LDN), whereas seven had right open donor nephrectomy (ODN); LDN was only considered if the renal vascular anatomy was favourable on the left. CTA and MRA images were analysed by two radiologists independently. The radiological and surgical findings were correlated after the surgery.

RESULTS

CTA showed 33 arteries and 32 veins (100% sensitivity) whereas MRA showed 32 arteries and 31 veins (97% sensitivity). CTA detected all five accessory renal arteries whereas MRA only detected one. CTA also identified all three accessory renal veins whereas MRA identified two. CTA had a sensitivity of 97% and 47% for left lumbar and left gonadal veins, whereas MRA had a sensitivity of 74% and 46%, respectively.

CONCLUSION

Multislice spiral CTA with three‐dimensional reconstruction was more accurate than MRA for both renal arterial and venous anatomy.
A dose‐dependent dual effect of oestrogen on voiding in the male mouse?
Authors: Streng Tomi K. , Talo Antti , Andersson Karl‐Erik , Santti Risto
Published: October 2005

OBJECTIVES

To explore the effect of different degrees of oestrogenization on male voiding, by treating adult castrated and 5α‐dihydrotestosterone (DHT)‐maintained male mice with different doses of oestrogens, as exposure of male mice to excessive amounts of oestrogens can cause bladder outlet obstruction (BOO); in addition, male mice lacking oestrogen receptor (ER)α (ERKO) or ERβ (BERKO) were studied to assess the importance of ER subtypes.

MATERIALS AND METHODS

Castrated, DHT‐maintained adult mice were treated with 17β‐oestradiol (E2; 50 and 250 µg/kg) or oestrone (E1; 5, 50 and 500 µg/kg) daily for 10 days. Control mice were treated only with the vehicle. BERKO and ERKO mice, and their wild‐type littermates used as their controls, remained untreated. Under anaesthesia, the bladder and distal urethra were exposed to record simultaneously the bladder pressure and urinary flow rate from the distal urethra.

RESULTS

E2‐treated mice showed obstructive voiding, seen as increased bladder pressure, decreased average flow rate and prolonged micturition time. This was also evident when a high dose (500 µg/kg) of E1 was used. After treatment with a dose of 50 µg/kg, the urodynamic variables were similar to those in the control mice. Surprisingly, after treatment with a low dose (5 µg/kg) all urodynamic variables improved. There was a minor increase in the bladder pressure in BERKO mice; ERKO mice had a significantly lower urinary flow rate.

CONCLUSIONS

High doses of oestrogens caused BOO in castrated, DHT‐maintained male mice. A small dose of E1 had a positive effect on voiding, suggesting that oestrogens are needed for normal male voiding. Reduced urinary flow rates in ERKO mice suggest that oestrogen effects on voiding are mediated at least partly via ERα.
Clinical Results of an Advanced SVT Detection Enhancement Algorithm
Authors: LEE MICHAEL A. , CORBISIERO RAFFAELE , NABERT DAVID R. , COMAN JAMES A. , GIUDICI MICHAEL C. , TOMASSONI GERY F. , TURK KYONG T. , BREITER DAVID J. , ZHANG YUNLONG
Published: October 2005

Introduction: Supraventricular tachycardia (SVT) has many characteristics that are similar to ventricular tachycardia (VT). This presents a significant challenge for the SVT‐detection algorithms of an implantable cardioverter defibrillator (ICD). A newly developed ICD, which utilizes a Vector Timing and Correlation algorithm as well as interval‐based conventional SVT discrimination algorithms (Rhythm ID™), was evaluated in this study.

Materials and Methods: This study was a prospective, multicenter trial that evaluated 96 patients implanted with an ICD at 21 U.S. centers. All patients were followed at 2 weeks, 1 month, and every 3 months post implant. A manual Rhythm ID reference vector was acquired prior to any arrhythmia induction. During testing, atrial tachyarrhythmias were induced first, followed by ventricular arrhythmia induction. Induced and spontaneous SVT and VT/ventricular fibrillation (VF) episodes recorded during the trial were annotated by physician investigators.

Results: The mean age of the patients implanted with an ICD was 67.3 ± 10.8 years. Eighty‐one percent of patients were male. The primary cardiovascular disease was coronary artery disease, and the primary tachyarrhythmia was monomorphic VT. Implementation of the Rhythm ID algorithm did not affect the VT/VF detection time. There were a total of 370 ventricular tachyarrhythmias (277 induced and 93 spontaneous) and 441 SVT episodes (168 induced and 273 spontaneous). Sensitivity for ventricular tachyarrhythmias was 100%, and specificity for SVT was 92% (94% and 91% for induced and spontaneous SVT, respectively). All patients had a successful manual Rhythm ID acquisition prior to atrial tachyarrhythmia induction. At the 1‐month follow‐up, the Rhythm ID references were updated automatically an average of 167.8 ± 122.7 times. Stored Rhythm ID references correlated to patients' normally conducted rhythm 100% at 2 weeks, and 98% at 1 month.

Conclusions: The Rhythm ID algorithm achieved 100% sensitivity for VT/VF, and 92% specificity for SVT. The manual and automatic Rhythm ID update algorithms successfully acquired references, and the updated references were highly accurate.
Junctional Rhythm—A Suitable Surrogate Endpoint in Catheter Ablation of Atrioventricular Nodal Reentry Tachycardia?
Authors: MCGAVIGAN ANDREW D. , RAE ALAN P. , COBBE STUART M. , RANKIN ANDREW C.
Published: October 2005

Introduction: Current AHA/ACC guidelines state that junctional rhythm (JR) is an acceptable endpoint in patients undergoing radiofrequency ablation (RFA) for narrow complex tachycardia in the presence of dual AV nodal physiology, but in the absence of inducible AVNRT. Only limited data are available on the utility of JR as a marker of successful slow pathway ablation. We sought to further characterize the sensitivity, specificity, and predictive value of JR in AVNRT ablation.

Methods: A retrospective analysis was performed of 387 consecutive patients with documented narrow complex tachycardia referred for ablation, with dual AV nodal physiology and inducible AVNRT at electrophysiological study. RFA of slow pathway was performed, with the presence or absence of JR recorded for each application and inducibility tested using atrial stimulation protocol and isoproterenol.

Results: Successful ablation was achieved in 385 of 387 patients using a total of 1,861 applications of radiofrequency energy. JR occurred in 692 applications, giving a sensitivity and specificity of JR as an indicator of successful ablation of 99.5% and 79.1% and a positive predictive value of 55.5%.

Conclusions: This study confirms that successful ablation of slow pathway seldom occurs in the absence of JR. Although JR almost invariably occurs with successful ablation, its lack of specificity and low positive predictive value questions the use of it as an endpoint in AVNRT ablations, and the guidelines should reflect this.
Inappropriate Sinus Tachycardia, Postural Orthostatic Tachycardia Syndrome, and Overlapping Syndromes
Authors: BRADY PETER A. , LOW PHILLIP A. , SHEN WIN K.
Published: October 2005

Background:
Inappropriate sinus tachycardia (IAST) and postural orthostatic tachycardia syndrome (POTS) are syndrome complexes with some distinctive features, overlapping clinical manifestations, and potential common mechanisms. Pathogenesis of these overlapping syndromes is poorly understood. Diagnostic and therapeutic approaches have not been standardized.

Purpose:
This article provides an overview of the definition, clinical presentation, and proposed mechanisms of IAST and other overlapping syndromes. A stepwise diagnostic approach is suggested. A multidisciplinary management scheme is outlined.

Methods:
A MEDLINE search for English‐language articles on IAST, POTS, and chronic orthostatic intolerance published up to 2005 was performed. Published data incorporated with our clinical experience were synthesized and presented in this review.

Results:
The population of IAST is heterogeneous and underlying mechanisms are complex and likely multifactorial. Evidence suggests that both cardiac and extracardiac causes are plausible. Regional and limited autonomic neuropathies, at least in part, can provide a mechanism‐based explanation of the cardiovascular indices and clinical symptoms in a significant number of patients with IAST. The regional abnormalities can be detected by autonomic testing. Among patients with IAST and evidence of autonomic dysregulation, an integrated autonomic, cardiovascular, and psychiatric management approach appears to be logical and rational when appropriate. Sinus node ablation could be considered in patients with persistent IAST in the absence of autonomic neuropathy and multisystem symptoms. Data from long‐term outcomes are lacking.

Conclusion:
The current understanding of IAST mechanisms is incomplete and management approach is not adequate. Significant effort needed in clinical research to improve therapeutic outcome.
Successful Pacemaker Lead Implantation via the Subclavian Vein Despite of High Degree Stenosis of the Vein
Authors: KOLB CHRISTOF , ZRENNER BERNHARD , SCHMITT CLAUS
Published: October 2005

This case reports on an 81‐year‐old man with implanted dual‐chamber pacemaker for binodal disease who required ventricular lead revision due to loss of ventricular capture. Successful placement of a new lead via the subclavian vein despite of high degree stenosis of the medial part of the vein is described using a very thin bipolar ventricular pacing lead. Currently available pacing electrodes for this purpose are reviewed.
Ventricular Tachycardias and Dilated Cardiomyopathy Caused by Fabry Disease
Authors: IGAWA OSAMU , MIAKE JUNICHIRO , HISATOME ICHIRO
Published: October 2005

Women with Fabry disease are considered to have a good prognosis. Here we report the clinical history of a female patient with severe Fabry disease before and after referral to our hospital. She was diagnosed to have a cardiac variant of Fabry disease since a left ventricular endmyocardial biopsy revealed specific features of this disease and that cardiac involvement was the sole manifestation. She developed sustained ventricular tachycardia and dilated cardiomyopathy requiring oral administration of amiodarone and a cardiac defibrillator implant.
Effects of implant surface microtopography on osteoblast gene expression
Authors: Masaki Chihiro , Schneider Galen B. , Zaharias Rebecca , Seabold Denise , Stanford Clark
Published: October 2005

Aim: The promotion of osteoblast attachment and differentiation has been evaluated on various implant surfaces. However, the effects of different implant surface properties on gene expression of key osteogenic factors are not fully understood.

Objective: The objectives of this study were to evaluate how topographical effects on titanium surface alter the expression of bone‐related genes and transcription factors.

Methods: Osteoblasts were cultured on titanium disks prepared with a titanium dioxide grit blasting (TiOBlast™) or grit blasted and etched with hydrofluoric acid (Osseospeed™), grit blasted and etched (SLA‐1), or grit blasted, etched and rinsed with N2 protection and stored in isotonic NaCl (SLA‐2) commercially pure titanium implant discs. High‐density cultures of human mesenchymal pre‐osteoblastic cells (HEPM 1486, ATCC) were grown for 72 h and real‐time PCR used for quantitative analysis of alkaline phosphatase (ALP), core‐binding factor α1 (Cbfa1), Osterix, Type I Collagen, Osteocalcin and bone sialoprotein II gene expression.

Results: Real‐time PCR showed significant (P<0.001) increases in ALP gene expression in osteoblasts grown on SLA‐2, relative to all other surfaces. Cbfa1/RUNX‐2 gene expression was significantly (P<0.01) increased on Osseospeed and TiOBlast surface as compared with SLA‐1 and SLA‐2 surfaces. The expression of Osterix had a trend similar to that of Cbfa1.

Conclusion: In conclusion, implant surface properties may contribute to the regulation of osteoblast differentiation by influencing the level of bone‐related genes and transcription factors in human mesenchymal pre‐osteoblastic cells.
Recommended placement torque when tightening an orthodontic mini‐implant
Authors: Motoyoshi Mitsuru , Hirabayashi Masayuki , Uemura Miwa , Shimizu Noriyoshi
Published: October 2005

Abstract: To determine an adequate placement torque for obtaining a better success rate of mini‐implants that are screwed into the buccal alveolar bone of the posterior region as an anchor for orthodontic treatment, implant placement torque (IPT) was measured. The subjects were 41 orthodontic patients (124 implants), with an average age of 24.9 years (SD 6.5 years), who had surgery to place titanium mini‐implants. The peak value of IPT was measured using a torque screwdriver. The success rate of the mini‐implant anchor for 124 implants was 85.5%. The mean IPT ranged from 7.2 to 13.5 N cm, depending on the location of the implants. There was a significant difference in the IPT between maxilla and mandible. The IPT in the mandible was, unexpectedly, significantly higher in the failure group than in the success group. Therefore, a large IPT should not be used always. According to our calculations of the risk ratio for failure, to raise the success rate of 1.6‐mm diameter mini‐implants, the recommended IPT is within the range from 5 to 10 N cm.
Hypocatalasemic Fibroblasts Accumulate Hydrogen Peroxide and Display Age‐Associated Pathologies
Authors: Wood Christopher S. , Koepke Jay I. , Teng Hua , Boucher Krissy K. , Katz Sharon , Chang Patrick , Terlecky Laura J. , Papanayotou Irene , Walton Paul A. , Terlecky Stanley R.
Published: October 2005

Human epidemiological studies point to an association of hypocatalasemia and an increased risk of age‐related disease. Unfortunately, the cellular and molecular manifestations of hypocatalasemia are only poorly understood. In this analysis, we have extensively characterized hypocatalasemic human fibroblasts and report that they amass hydrogen peroxide and are oxidatively damaged. Protein and DNA alike are affected, as are functioning and biogenesis of peroxisomes – the subcellular organelles which normally house catalase. Despite these pathologies and their relative inability to grow, the cells do not appear to be intrinsically senescent. With the goal of restoring oxidative balance and perhaps reversing some of the accumulated damage to critical cellular components, we transduced hypocatalasemic fibroblasts with a form of catalase specifically designed to efficiently traffic to peroxisomes. We show the strategy is extremely effective, with dramatic reductions seen in cellular hydrogen peroxide levels. Future longitudinal studies aimed at examining the effects of a more continuous and long‐term protein therapy may now commence.
Spectroscopic and kinetic properties of the horseradish peroxidase mutant T171S
Authors: Howes Barry D. , Brissett Nigel C , Doyle Wendy A. , Smith Andrew T. , Smulevich Giulietta
Published: October 2005

Studies on horseradish peroxidase C and other haem peroxidases have been carried out on selected mutants in the distal haem cavity providing insight into the functional importance of the distal residues. Recent work has demonstrated that proximal structural features can also exert an important influence in determining the electronic structure of the haem pocket. To extend our understanding of the significance of proximal characteristics in regulating haem properties the proximal Thr171Ser mutant has been constructed. Thr171 is an important linking residue between the structural proximal Ca2+ ion and the proximal haem ligand, in particular the methyl group of Thr171 interdigitates with other proximal residues in the core of the enzyme. Although the mutation induces no significant changes to the functional properties of the enzyme, electronic absorption and resonance Raman spectroscopy reveal that it has a highly selective affect on the reduced state of the enzyme, effectively stabilizing it, whilst the electronic properties of the Fe(III) state unchanged and essentially identical to those of the native protein. This results in a significant change in the Fe2+/Fe3+ redox potential of the mutant. It is concluded that the unusual properties of the Thr171Ser mutant reflect the loss of a structural restraint in the proximal haem pocket that allows ‘slippage’ of the proximal haem ligand, but only in the reduced state. This is a remarkably subtle and specific effect that appears to increase the flexibility of the reduced state of the mutant compared to that of the wild‐type protein.