bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional and expression analysis of Arabidopsis SPA genes during seedling photomorphogenesis and adult growth
Authors: Fittinghoff Kirsten , Laubinger Sascha , Nixdorf Markus , Fackendahl Petra , Baumgardt Rosalinde‐Louise , Batschauer Alfred , Hoecker Ute
Published: July 2006

The four members of the Suppressor of phyA‐105 (SPA) gene family function to inhibit photomorphogenesis in dark‐ and light‐grown seedlings. Additionally, SPA1–SPA4 regulate elongation growth of adult plants. In these processes, SPA2, SPA3 and SPA4 have overlapping but distinct functions. Here, we have further investigated the role of SPA1 which is partially masked by functional redundancy. We show that SPA1 represses not only red, far‐red and blue light responses in a PHYA‐dependent fashion, but also acts to suppress light signaling in darkness. We demonstrate that deletion‐derivatives of SPA1 lacking the complete N‐terminus or part of the kinase‐like domain retain SPA1 function in light‐ and dark‐grown seedlings, while deletion of the constitutive photomorphogenesis  1 (COP1)‐interacting coiled‐coil domain eliminates SPA1 activity. This suggests that the coiled‐coil domain and the WD‐repeat domain of SPA1 are sufficient for SPA1 function. An analysis of spa2 spa3 spa4 triple mutants demonstrates that SPA1, like SPA2, is sufficient for normal etiolation of dark‐grown seedlings. In light‐grown seedlings and adult plants, in contrast, SPA1 function is divergent from SPA2 function, with SPA1 playing the predominant role. Levels of SPA1, SPA3 and SPA4 transcript are increased by red, far‐red and blue light, consistent with a role of these three SPA genes in light‐grown seedlings. The abundance of SPA2 mRNA, in contrast, is not altered by light. Taken together, the analysis of SPA transcript levels suggests that differences in SPA gene expression patterns contribute to divergence in SPA1–SPA4 function.
De novo malignancies following liver transplantation: a case–control study with long‐term follow‐up
Authors: Yao Francis Y , Gautam Manjushree , Palese Caren , Rebres Raquel , Terrault Norah , Roberts John P. , Peters Marion G.
Published: July 2006

Abstract:  Background:  Long‐term survival data on de novo malignancy are limited following orthotopic liver transplantation (OLT) when compared with controls without malignancies.

Methods:  Over a 12 yr period at our institution, 50 of 1043 patients (4.8%) who underwent OLT were identified to have 53 de novo malignancies. The clinical characteristics and survival of these patients were retrospectively reviewed and compared with a control cohort of 50 OLT recipients without malignancy matched with the incidence cases by age, year of OLT, sex, and type of liver disease.

Results:  Chronic hepatitis C, alcohol and primary sclerosing cholangitis were the three leading causes of liver disease. Skin cancer was the most common malignancy (32%), followed by gastrointestinal (21%), including five small bowel tumors, and hematologic malignancies (17%). The cases and controls were not significantly different in the immunosuppressive regimen (p = 0.42) or the number of rejection episodes (p = 0.92). The five‐ and 10‐year Kaplan–Meier survival rates for the cases were 77% and 34%, respectively, vs. 84% and 70%, respectively, for the controls (p = 0.02 by log‐rank test). Patients with skin cancers had survival similar to the controls, but significantly better than non‐skin cancers (p = 0.0001). The prognosis for patients with gastrointestinal tumors was poor, with a median survival of 8.5 months after the diagnosis.

Conclusion:  In this single institutional study, de novo malignancies after OLT were uncommon. Patients with non‐skin cancer after OLT had diminished long‐term survival compared with the controls. Our results differ from other reports in the high incidence of gastrointestinal malignancies with attendant poor prognosis.
Characterization of CD4, CD8, CD56 positive lymphocytes and C4d deposits to distinguish acute cellular rejection from recurrent hepatitis C in post‐liver transplant biopsies
Authors: Jain Ashok , Ryan Charlotte , Mohanka Ravi , Orloff Mark , Abt Peter , Romano Joan , Bryan Leah , Batzold Pam , Mantry Parvez , Bozorgzadeh Adel
Published: July 2006

Abstract:  Introduction:  Hepatitis C viral (HCV) infection is the most common cause for liver transplantation (LTx) in USA. Hepatitis C viral recurrence in liver allograft is almost universal, which is often difficult to distinguish from acute cellular rejection (ACR).

Aim:  Aim of the present study is to examine the differences between distribution of CD4, CD8, CD56 positive lymphocytes, and C4d deposits in patients with ACR and recurrent HCV.

Patients and methods:  As a pilot project, a group of five post‐LTx HCV RNA negative patients, strongly suspicious for ACR based on clinical findings and history of medication non‐compliance and another group of five post‐LTx HCV positive, medication compliant patients with abnormal liver function were retrospectively selected. Liver biopsies of these patients were stained with monoclonal CD4, CD8, CD56, and polyclonal C4d antibodies and compared.

Results:  Mean CD4, CD8, and CD56 counts in ACR group were 156.7 ± 17.6, 35.4 ± 8.8, and 1.0 ± 1.8/HPF, respectively and were 89.7 ± 41.3, 20.3 ± 23.2, and 0.6 ± 0.9/HPF, respectively in HCV recurrence group. Biopsies of four of five patients with ACR demonstrated moderate to strong C4d staining, whereas all patients with recurrent HCV had none to mild C4d staining.

Conclusion:  Mean CD4, CD8, and CD56 were similar for acute rejection and recurrent HCV infection. However, 80% of patients with ACR showed moderate to strong staining for C4d and all recurrent HCV patients showed none to mild C4d staining.
Relative risk of new‐onset diabetes during the first year after renal transplantation in patients receiving tacrolimus or cyclosporine immunosuppression
Authors: Hoitsma Andries J. , Hilbrands Luuk B.
Published: July 2006

Abstract: Clinical trials have consistently shown a higher incidence of new‐onset diabetes mellitus with tacrolimus than cyclosporine. However, in protocol‐driven studies steroid doses are comparable in both treatment arms, while in clinical practice steroid dose used in conjunction with tacrolimus or cyclosporine may differ. This retrospective study analysed renal transplant recipients without pre‐existing diabetes receiving tacrolimus (n = 100) or cyclosporine (n = 100) for whom one‐year follow‐up data were available. Diabetes was defined as use of insulin or oral hypoglycemic agents; fasting glucose >6.9 mmol/L; or non‐fasting glucose >11 mmol/L on three consecutive occasions. Tacrolimus‐treated patients were significantly older than cyclosporine‐treated patients (49 ± 14 vs. 44 ± 13 yr, p < 0.05) and received a significantly lower cumulative dose of corticosteroids over the first three months post‐transplant (1284 ± 379 vs. 1714 ± 486 mg, p < 0.0001). At 3, 6, 9 and 12 months significantly more tacrolimus‐treated patients had new‐onset diabetes than cyclosporine‐ treated patients. At 12 months, 18 patients receiving tacrolimus and two receiving cyclosporine had diabetes (p < 0.0001). There was a clear relationship between age and incidence of new‐onset diabetes at three months in the tacrolimus cohort. After stratifying patients by age group, the frequency of diabetes was significantly higher with tacrolimus than with cyclosporine in patients aged 40–60 yr [8/46 (17.4%) vs. 2/48 (4.2%), p < 0.05] and >60 yr [9/28 (32.1%) vs. 0/14 (0%), p < 0.05]. The mean tacrolimus trough level during the first three months was similar in patients with diabetes (13.1 ± 2.3 ng/mL) or without diabetes (13.0 ± 2.8 ng/mL, n.s.). These results indicate that new‐onset diabetes is strongly and significantly associated with tacrolimus vs. cyclosporine in renal transplant recipients, even when steroid dosing is lower with tacrolimus.
Relevance of cardioverter defibrillators for the prevention of sudden cardiac death on the timing of heart transplantation
Authors: Grigioni Francesco , Boriani Giuseppe , Barbieri Andrea , Russo Antonio , Reggianini Letizia , Bursi Francesca , Potena Luciano , Ricci Caterina , Fallani Francesco , Coccolo Fabio , Magnani Gaia , Magelli Carlo , Modena Maria G. , Branzi Angelo
Published: July 2006

Abstract:  Information on the incidence of decompensation of chronic heart failure (CHF) in heart transplantation (HT) candidates eligible for prophylactic implantable cardioverter defibrillators (ICD) could provide insights into the influence of ICD on the timing for HT.

Methods:  We investigated the prevalence of candidates satisfying SCD‐HeFT and MADIT‐II criteria for prophylactic ICD among patients (n = 317) with CHF referred to our tertiary center for HT. In addition to standard clinical and laboratory assessments, baseline evaluation included two‐dimensional standard transthoracic echocardiogram and 12‐lead electrocardiogram.

Results:  At baseline, 19% of patients (n = 60) satisfied MADIT II criteria, and 58% (n = 185) fulfilled SCD‐HeFT criteria. A total of 60% patients (n = 190) were eligible for prophylactic ICD implantation according to at least one set of criteria. Five‐yr CHF decompensation‐free survival was 68 ± 4% in patients eligible for prophylactic ICD (p = 0.003), (RR 2.5, 95% CI 1.35–4.63).

Conclusions:  SCD‐HeFT could imply a threefold rise in ICD eligibility in tertiary settings. As ICD‐eligible patients would likely remain at high risk of progressive ventricular dysfunction, strict follow‐up should be considered extremely important to allow a timely referral for HT.
Radiofrequency thermal ablation of hepatocellular carcinoma before liver transplantation – a clinical and histological examination
Authors: Martin Adrian P. , Goldstein Robert M. , Dempster Jane , Netto George J. , Katabi Nora , Derrick Howard C. , Altrabulsi Basel , Jennings Linda W. , Ueno Takehisa , Chinnakotla Srinath , Dawson Sherfield , Randall Henry B. , Levy Marlon F. , Onaca Nicholas , Sanchez Edmund Q. , Orr Douglas , Klintmalm Goran B.
Published: July 2006

Abstract:  Background:  Radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) is an optional treatment for patients awaiting liver transplantation (LTX). The study evaluates the efficacy of RFA in the explanted liver and its effect on patient outcome.

Material and method:  Forty‐seven patients underwent RFA and were listed for transplant between January 1998 and May 2003. The patients were divided into two groups: transplanted and non‐transplanted. Both groups were evaluated in terms of tumor characteristics, recurrence, mortality rate, and time on the waiting list. The ablation sites in the explanted livers were examined for percentage of necrosis by Hematoxylin & Eosin (H&E) stain and by TUNEL stain.

Results:  Transplantation was carried out in 35 patients (74.5%). Ten patients (21.3%) died before transplant or were removed from the wait list, while two patients (4.2%) are still listed. Mortality and tumor‐related mortality were significantly higher in the non‐transplanted group. The time spent on the waiting list was longer in the non‐transplanted patients (350 vs. 186 d average, p = 0.0345). Thirty‐eight ablation sites were examined in the explanted livers. The percentage of tumor necrosis by TUNEL staining was 19.6% higher than that reported by H&E staining. After TUNEL staining, 28 sites (73.7%) had more than 90% necrosis, eight sites (21.0%) had 50–90%, and two sites (5.3%) had less than 50% necrosis.

Conclusions:  RFA and LTX can be used successfully in HCC patients, and in most cases, tumor necrosis can be achieved with ultrasound‐guided RFA. H&E stain tends to under‐represent the amount of tumor necrosis on the ablation sites. Survival of RFA patients after LTX is excellent.
Association of core promoter mutations with viral breakthrough in chronic hepatitis B patients on long‐term lamivudine therapy
Authors: Kazim Syed Naqui , Chauhan Ranjit , Das Bhudev Chandra , Sarin Shiv Kumar
Published: July 2006

Background and Aim:  Virologic breakthrough (VBTH) during long‐term lamivudine therapy is believed to be due to the emergence of rtYM204I/VDD mutants. We observed VBTH in 17 of 67 patients receiving long‐term lamivudine therapy. The YMDD mutant at the onset of VBTH and/or subsequently was seen in eight (47%) of 17 such patients. We investigated other potential loci in the viral genome contributing to VBTH.

Methods:  Chronic hepatitis B (CHB) patients (n = 17) on long‐term (≥12 months) lamivudine therapy who had at least one episode of VBTH were selected (group I). Age, sex, serology and baseline viral load matched patients on long‐term lamivudine without VBTH (n = 12) served as controls (group II). Hepatitis B virus (HBV) DNA sequences were analyzed for pre‐S, surface, polymerase, core promoter, precore and core regions and were compared with sequences of respective genotypes.

Results:  Group I patients with VBTH (n = 17) either had rtYM204I/VDD mutations (n = 8, group Ia YMDD) or no rtYM204I/VDD mutations (n = 9, group Ib non‐YMDD). Group Ia patients had median baseline HBV DNA of 2794 pg/mL (range 3–9166 pg/mL) and a mean alanine aminotransferase (ALT) level of 86 ± 33 IU/L. In group Ib, the median baseline viral DNA was 916 pg/mL (range 8.3–5787 pg/mL) and the mean ALT was 61 ± 38 IU/L. The first VBTH in group Ia and Ib patients was noted at 21 ± 9 months and 15.2 ± 5.9 months, respectively, with a rise in HBV DNA levels from undetectable limits to 952 pg/mL (range 4.3–4875 pg/mL) and 571 pg/mL (range 1.2–1970 pg/mL), respectively. Core promoter mutations were seen in five of eight (62.5%) and in six of nine (66.6%); classic double mutations (A1762T/G1764A) of core promoter region were detected in two and three patients and novel double mutations of core promoter (G1764T/C1766G) in one patient each of group Ia and Ib patients, respectively. Compared to 11 (68%) of 17 group I patients, only three (25%) of 12 patients in group II had core promoter mutations (P < 0.05). No patient in group II had double mutations of the core promoter region. No significant difference in viral mutations was seen in any other region of the viral genome between group I and group II patients. In group I, none of the 15 patients (two died of hepatocellular carcinoma), but five (42%) group II patients achieved hepatitis B e antigen (HBeAg) seroconversion and sustained response by month 24 (P < 0.05).

Conclusion:  Both core promoter and YMDD motif mutation(s) are associated with VBTH in patients on long‐term lamivudine therapy. Whether or not these promoter mutations in the absence of YMDD mutations confer drug resistance needs to be studied in an in vitro cell culture system, as they could create novel and stronger binding sites for hepatocyte nuclear factors.
The state‐contingent approach to production under uncertainty*
Authors: Quiggin John , Chambers Robert G.
Published: July 2006

The central claim of this paper is that the state‐contingent approach provides the best way to think about all problems in the economics of uncertainty, including problems of consumer choice, the theory of the firm, and principal–agent relationships. This claim is illustrated by recent developments in, and applications of, the state‐contingent approach.
Supply and demand for commodity components: implications of free trade versus the AUSFTA for the US dairy industry*
Authors: Alston Julian M. , Balagtas Joseph V. , Brunke Henrich , Sumner Daniel A.
Published: July 2006

During the negotiations on the Australia–US free trade agreement (AUSFTA), the US dairy industry vigorously opposed opening the US market to imports of Australian dairy products on the grounds that the US industry would be devastated. Subsequently, the agreement signed in February 2004 made an exception for dairy, providing for only limited quota expansion and no free trade, even at the end of the long implementation period. This paper presents a simulation model of world dairy markets, represented by supply and demand equations for fat and non‐fat components of milk and manufactured dairy products. We use the model to analyse the effects on US milk markets of both a hypothetical agreement, allowing free bilateral trade in dairy products, and the actual AUSFTA. An important contribution to the literature is the derivation of explicit supply and demand relationships for milk components. The components model allows an analysis of long‐term production, consumption, and trade patterns that is not tied to specific, fungible products. Simulations indicate that increased imports from Australia resulting from bilateral trade liberalisation would have resulted in small reductions in US milk prices and production. The much smaller increases in Australian access to the US market under the actual AUSFTA will have even smaller, almost negligible, impacts.
Capacity reduction, quota trading and productivity: the case of a fishery*
Authors: Fox Kevin J. , Grafton R. Quentin , Kompas Tom , Che Tuong Nhu
Published: July 2006

We present the first ex post study that quantitatively analyses the effects of a licence buy‐back and enhanced quota trading on the profitability and productivity of individual vessels in a fishery. Using firm‐level data and a profit index decomposition method, we find that small and large vessels and three different trawler fleets all experienced substantial productivity gains in the year immediately following a licence buy‐back and the establishment of a quota brokerage service. The apparent ongoing benefits of the buy‐back and increased quota trading over the sample period are in stark contrast to the generally unfavourable long‐term outcomes commonly associated with vessel buy‐backs in input‐controlled fisheries.
Dynamic adaptation to resource scarcity and backstop availability: theory and application to groundwater*
Authors: Koundouri Phoebe , Christou Christina
Published: July 2006

In this paper we analyse the optimal management of a renewable resource (groundwater) with stock‐dependent extraction cost and a backstop substitute, facing two‐sector linear demands. Application to the Kiti region in Cyprus demonstrates the model's performance and is used to test for the difference between optimal and myopic behaviour. It is found that the presence of a backstop resource diminishes the importance of optimal dynamic behaviour, whereas in the absence of backstop the optimal control solution yields a value for social welfare significantly larger than the myopic policy.
Sensitivity of Marine‐Reserve Design to the Spatial Resolution of Socioeconomic Data
Authors: RICHARDSON ELIZABETH A. , KAISER MICHEL J. , EDWARDS‐JONES GARETH , POSSINGHAM HUGH P.
Published: July 2006

Abstract:  Socioeconomic considerations should have an important place in reserve design. Systematic reserve‐selection tools allow simultaneous optimization for ecological objectives while minimizing costs but are seldom used to incorporate socioeconomic costs in the reserve‐design process. The sensitivity of this process to biodiversity data resolution has been studied widely but the issue of socioeconomic data resolution has not previously been considered. We therefore designed marine reserves for biodiversity conservation with the constraint of minimizing commercial fishing revenue losses and investigated how economic data resolution affected the results. Incorporating coarse‐resolution economic data from official statistics generated reserves that were only marginally less costly to the fishery than those designed with no attempt to minimize economic impacts. An intensive survey yielded fine‐resolution data that, when incorporated in the design process, substantially reduced predicted fishery losses. Such an approach could help minimize fisher displacement because the least profitable grounds are selected for the reserve. Other work has shown that low‐resolution biodiversity data can lead to underestimation of the conservation value of some sites, and a risk of overlooking the most valuable areas, and we have similarly shown that low‐resolution economic data can cause underestimation of the profitability of some sites and a risk of inadvertently including these in the reserve. Detailed socioeconomic data are therefore an essential input for the design of cost‐effective reserve networks.
DNA Registers of Legally Obtained Wildlife and Derived Products as Means to Identify Illegal Takes
Authors: PALSBØLL PER J. , BÉRUBÉ MARTINE , SKAUG HANS J. , RAYMAKERS CAROLINE
Published: July 2006

Abstract:  The exploitation and sale of wildlife species that are endangered in only part of their range present regulators with the critical challenge of separating legal from illegal takes. Wildlife DNA registers created from tissue samples of legally obtained individual wildlife specimens can address this problem by allowing managers to identify unregistered (presumably illegally obtained) specimens. We tested the effectiveness of the only current, fully operational wildlife DNA register of individual genetic profiles collected from legally caught minke whales (Balaenoptera acutorostrata). Twenty minke whale tissue samples collected at markets in Norway and 2 additional samples collected from beached minke whales in Denmark were genotyped at 12 loci used by the Norwegian minke whale DNA register. Genetic profiles of these samples then were compared against the 2676 individual profiles deposited in the Norwegian register. The high number of genetic markers used to identify individuals in our study allowed consistent matching of sample and reference profiles despite an overall error rate (due to experimental and interlaboratory data standardization) estimated at 0.015 per locus. Of the 22 test samples only the 2 Danish samples failed to match an existing profile in the Norwegian minke whale DNA register. Our results show that the basic principle of wildlife DNA registers can work in a real‐life situation. The strength of wildlife DNA registers lies in their ability to unambiguously identify unregistered specimens with the aid of sensitive genetic methods that enable analysis of highly processed or degraded tissue samples. Our study also highlights a number of methodological problems such as laboratory errors and interlaboratory data standardization, which need be addressed to ensure a successful implementation of wildlife DNA registers.
Fragments as Islands: a Synthesis of Faunal Responses to Habitat Patchiness
Authors: WATLING JAMES I. , DONNELLY MAUREEN A.
Published: July 2006

Abstract:  Scientific interest in the impact of habitat fragmentation on biodiversity is increasing, but our understanding of fragmentation is clouded by a lack of appreciation for fundamental similarities and differences across studies representing a wide range of taxa and landscape types. In an effort to synthesize data describing ecological responses of animals to fragmentation across two classes of independent variables (taxonomic group and landscape), we sampled 148 studies of five major faunal groups from the primary literature and analyzed data on 13 variables extracted from those studies. We focused our analyses on three classes of dependent variables (effects of area and isolation on species richness, z values, and nestedness and species composition). Area ranged over more orders of magnitude than isolation and tended to explain more variation in species richness than isolation. There were few matrix or taxon effects on the patterns we investigated, although we did find that sky islands tended to manifest isolation effects on both species richness and nestedness more frequently than other patch types. Sky islands may offer insight into the future of habitat patches fragmented by contemporary habitat loss, and because they show a stronger effect of isolation than other patch types, we suggest that isolation will play an increasing role in the biology of habitat fragments. We use multiple lines of evidence to suggest that our understanding of the role of isolation on community assembly in fragmented landscapes is inadequate. Finally, our observation that consistent taxonomic differences in community patterns were minimal suggests that conservation actions intended to mitigate the negative effects of extinction may have far‐reaching effects across taxonomic groups.
Effectiveness of Environmental Cluster Analysis in Representing Regional Species Diversity
Authors: TRAKHTENBROT ANA , KADMON RONEN
Published: July 2006

Abstract:  A major challenge of regional conservation planning is the identification of sets of sites that together represent the overall biodiversity of the relevant region. Environmental cluster analysis (ECA) has been proposed as a potential tool for efficient selection of conservation sites, but the consequences of methodological decisions involved in its application have not been tested so far. We evaluated the performance of ECA with respect to two such decisions: the choice of the clustering algorithm (single linkage, complete linkage, unweighted arithmetic average, unweighted centroid, Ward's minimum variance, and the ALOC algorithm) and the weight given to different groups of environmental variables (rainfall, temperature, and lithology). Specifically we tested how these decisions affect the spatial configuration of clusters of sites defined by the ECA, whether and how they affect the effectiveness of the ECA (i.e., its ability to represent regional species diversity), and whether the effectiveness of alternative methods of hierarchical clustering can be predicted a priori based on the cophenetic correlation. We used an extensive database of the flora of Israel to test these questions. Differences in both the clustering algorithm and the weighting regime had considerable effects on the spatial configuration of the ECA clusters. The single‐linkage algorithm produced mostly single‐cell clusters plus a single large‐sized cluster and was therefore found inappropriate for environmental regionalization. The effectiveness of the ECA was also sensitive to changes in the clustering algorithm and the weighting regime. Yet, most combinations of clustering algorithms and weighting regimes performed significantly better in capturing regional biodiversity than random null models. The main deviation was classifications based on Ward's minimum variance algorithm, which performed less well relative to all other algorithms. The two algorithms that showed the highest effectiveness (unweighted average and unweighted centroid clustering) also exhibited the highest values of the cophenetic correlation, suggesting that this index may serve as a potential indicator for the effectiveness of alternative ECA algorithms.
Clinical Presentation of Hypernatremia in Elderly Patients: A Case Control Study
Authors: Chassagne Philippe , Druesne Laurent , Capet Corinne , Ménard Jean François , Bercoff Eric
Published: July 2006

OBJECTIVES: To assess early clinical signs and their prognostic value in elderly patients with hypernatremia.

DESIGN: Prospective, case control study of 150 patients with hypernatremia matched to 300 controls.

SETTING: Multicenter study including seven short‐ and long‐term geriatric care facilities.

MEASUREMENTS: Clinical assessment of hydration status at bedside, such as abnormal skin turgor or dry oral mucosa. Secondary outcome measures: 30‐day mortality rate and clinical indicators (assessed at the peak of natremia) associated with mortality.

RESULTS: Patients and controls were comparable in terms of drugs and underlying diseases, except for history of dementia, which was more frequent in patients than in controls. Patients were significantly more likely than controls to have low blood pressure, tachycardia, dry oral mucosa, abnormal skin turgor, and recent change of consciousness. Only three clinical findings were found in at least 60% of patients with hypernatremia: orthostatic blood pressure and abnormal subclavicular and forearm skin turgor. The latter two signs were significantly more frequent in patients with hypernatremia. Four other signs (tachycardia, abnormal subclavicular skin turgor, dry oral mucosa, and recent change of consciousness) had a specificity of greater than 79%. Using logistic regression, four signs were significantly and independently associated with hypernatremia: abnormal subclavicular and thigh skin turgor, dry oral mucosa, and recent change of consciousness. The mortality rate was 41.5% and was significantly higher in patients with hypernatremia. The status of consciousness when hypernatremia was diagnosed was the single prognostic indicator associated with mortality (odds ratio=2.3, 95% confidence interval=1.01–5.2).

CONCLUSION: Most of the classical signs of dehydration are irregularly present in patients with hypernatremia. Caregivers should carefully screen any variations in consciousness, because they may reveal severe hypernatremia.
Rural–Urban Differences in Medical Care for Nursing Home Residents with Severe Dementia at the End of Life
Authors: Gessert Charles E. , Haller Irina V. , Kane Robert L. , Degenholtz Howard
Published: July 2006

OBJECTIVES: To identify factors associated with the use of selected medical services near the end of life in cognitively impaired residents of rural and urban nursing homes.

DESIGN: Retrospective cohort study using Centers for Medicare and Medicaid Services administrative data for 1998 through 2002.

SETTING: Minnesota and Texas nursing homes.

PARTICIPANTS: Nursing home residents aged 65 and older with severe cognitive impairment who subsequently died during 2000/01.

MEASUREMENTS: Minimum Data Set and Medicare Provider Analysis and Review, Hospice, and Denominator files were used to identify subjects and to assess medical service use. U.S. Department of Agriculture metro–nonmetro continuum county codes defined rural (codes 6–9) and urban (codes 0–2) nursing homes. Nursing home residents with hospice or health maintenance organization benefits were excluded. Use of hospital services at the end of life was adjusted for use of corresponding services before the last year of life. Outcome variables were feeding tube use, any hospitalization, more than 10 days of hospitalization, and intensive care unit (ICU) admission.

RESULTS: The population included 3,710 subjects (1,886 rural, 1,824 urban). In multivariable logistic regression analyses (all P<.05), feeding tube use was more common in urban nursing home residents, whereas rural nursing home residents were at greater risk for hospitalization. Rural residence was also associated with lower risk of more than 10 days of hospitalization and ICU admission. Nonwhite race and stroke were associated with higher use of all services.

CONCLUSION: Rural nursing home residence is associated with lower likelihood of use of the most‐intensive medical services at the end of life.
Fracture Resistance of Fiber‐Reinforced PMMA Interim Fixed Partial Dentures
Authors: Hamza Tamer A. , Rosenstiel Stephen F. , El‐Hosary Mohamed M. , Ibraheem Rabab M.
Published: July 2006

Purpose: To compare different fiber reinforcements on fracture toughness of interim polymethyl methacrylate materials and then use the best combination to determine the optimal position for fiber placement in an interim 3‐unit fixed partial denture (FPD).

Materials and Methods: In the first stage of the study, five groups of notched fracture toughness specimens were fabricated and loaded to failure (Instron): (1) unreinforced (control); (2) reinforced with pre‐impregnated silanized E‐glass fibers (Fibrestick); (3) cold plasma‐treated woven polyethylene fibers (Ribbond triaxial); (4) pre‐impregnated silanized plasma‐treated woven polyethylene fibers (Construct); and (5) 1.0‐mm‐diameter stainless steel wire. In the second stage, the optimal position (occlusal, middle, or cervical third of pontic) for reinforcement with glass fibers (regimen 2) was tested by loading a 3‐unit FPD to failure. All groups were compared with analysis of variance (α < 0.05).

Results: The fracture toughness (in MPam1/2) for each reinforced group (Fibrestick 2.74 ± 0.12, Construct fibers 2.59 ± 0.28, Ribbond triaxial 2.13 ± 0.20, and orthodontic wire 1.66 ± 0.09) was statistically greater (p< 0.05) than for the unreinforced group (control = 1.25 ± 0.006). Fracture loads for FPDs were greatest when the fiber reinforcements were placed in the cervical third (cervical = 1165 N).

Conclusions: The use of fiber and, to a lesser extent, orthodontic wire is an effective method to reinforce interim restoration resins.
Influence of Flask Closure and Flask Cooling Methods on Tooth Movement in Maxillary Dentures
Authors: Consani Rafael L.X. , Domitti Saide S. , Mesquita Marcelo F. , Consani Simonides
Published: July 2006

Purpose: This study investigated the tooth movement of standardized simulated dentures processed by traditional closure or the new Rafael Saide (RS) tension system when cooled in the curing water itself or in curing water followed by bench storage for 3 hours.

Materials and Methods: Forty stone casts were formed from a mold of an edentulous maxillary arch. The wax denture record bases were made on the casts; the height of the wax rim occlusion was 20 mm in the labial sulcus of the cast and 10 mm in the posterior region. The upper stone cast was mounted on a Mondial 4000 semi‐adjustable articulator with wax rim interocclusal references in relation to the lower stone cast teeth. Metallic pins were placed in the incisal border of the maxillary central incisors (I), labial cusp of the first premolars (PM), and mesiolabial cusp of the second molars (M). The incisor‐to‐incisor (I–I), premolar‐to‐premolar (PM–PM), and molar‐to‐molar (M–M) transversal distances and left incisor‐to‐left molar (LI–LM), and right incisor‐to‐right molar (RI–RM) anteroposterior distances were measured before and after denture polymerization with an optical microscope with a tolerance of 0.0005 mm. For traditional closure, the dentures were flasked conventionally in standard metallic flasks, which were afterward placed in spring clamps. For the new RS system closure, the flasks were pressed between the metallic plates of the tension system after the final closure. The Clássico heat‐polymerizing acrylic resin dough was packed in the flasks under a final packing pressure of 1.250 kgf. Twelve hours after flask closure, the dentures were polymerized in a moist heat‐polymerizing cycle for 9 hours at 74°C. The denture was deflasked after cooling in the water of the polymerizing cycle (groups A and C) or in the water of the polymerizing cycle and then bench‐stored for 3 hours (groups B and D). Collected data were analyzed with analysis of variance and Tukey's test (p< 0.05).

Results: There was no statistically significant difference (p> 0.05) between the conventional and new RS system closure methods for the transversal distances after polymerization in all studied groups. The anteroposterior distances did not change with deflasking after water bath cooling. There were statistically significant differences (p< 0.05) in the anteroposterior distances with deflasking after water bath cooling and then bench storage for 3 hours.

Conclusion: Tooth movement was similar in dentures processed by traditional closure and by the new RS tension system, with the exception of the anteroposterior distances when the flasks were cooled in their own curing water and bench‐stored for 3 hours.
Effect of Disinfectants on the Hardness and Roughness of Reline Acrylic Resins
Authors: Azevedo Andrea , Machado Ana Lucia , Vergani Carlos Eduardo , Giampaolo Eunice Teresinha , Pavarina Ana Cláudia , Magnani Romeo
Published: July 2006

Purpose: Potential effects on hardness and roughness of a necessary and effective disinfecting regimen (1% sodium hypocholorite and 4% chlorhexidine) were investigated for two hard chairside reline resins versus a heat‐polymerizing denture base acrylic resin.

Materials and Methods: Two standard hard chairside reliners (Kooliner and Duraliner II), one heat‐treated chairside reliner (Duraliner II +10 minutes in water at 55°C), and one standard denture base material (Lucitone 550) were exposed to two disinfecting solutions (1% sodium hypochlorite; 4% chlorhexidine gluconate), and tested for two surface properties [Vickers hardness number (VHN, kg/mm2); Roughness (Ra, μm)] for different times and conditions (1 hour after production, after 48 hours at 37 ± 2°C in water, after two disinfection cycles, after 7 days in disinfection solutions, after 7 days in water only). For each experimental condition, eight specimens were made from each material. Data were analyzed by analysis of variance followed by Tukey's test, and Student's t‐test (p= 0.05).

Results: For Kooliner (from 6.2 ± 0.3 to 6.5 ± 0.5 VHN) and Lucitone 550 (from 16.5 ± 0.4 to 18.4 ± 1.7 VHN), no significant changes in hardness were observed either after the disinfection or after 7 days of immersion, regardless of the disinfectant solution used. For Duraliner II (from 4.0 ± 0.1 to 4.2 ± 0.1 VHN), with and without heat treatment, a small but significant increase in hardness was observed for the specimens immersed in the disinfectant solutions for 7 days (from 4.3 ± 0.2 to 4.8 ± 0.5 VHN). All materials showed no significant change in roughness (Kooliner: from 0.13 ± 0.05 to 0.48 ± 0.24 μm; Duraliner II, with and without heat treatment: from 0.15 ± 0.04 to 0.29 ± 0.07 μm; Lucitone 550: from 0.44 ± 0.19 to 0.49 ± 0.15 μm) after disinfection and after storage in water for 7 days.

Conclusions: The disinfectant solutions, 1% sodium hypochlorite and 4% chlorhexidine gluconate, caused no apparent damage on hardness and roughness of the materials evaluated.
Fabrication of a Laser‐Welded Fixed–Detachable Prosthesis for Immediate Loading
Authors: Kuo Shang‐lun , El‐Gendy Tamer , Chou James , Miller R. B.
Published: July 2006

Immediate loading of dental implants in completely edentulous patients is receiving great attention. Standard surgical protocol is used with primary stabilization of the implants as a goal. The restorative dentist must coordinate with the surgeon and the laboratory technician to make immediate loading a reality for the completely edentulous patient. This article describes a technique developed to fabricate an immediately loaded fixed–detachable prosthesis using laser welding technology. Advantages, which are applicable to various implant systems and patients, are discussed.
Inapparent Double Puncture of the Femoral Artery and Vein An Important Complication of Temporary Cardiac Pacing by the Transf emoral Approach
Authors: FALKOFF MICHAEL , HEINLE ROBERT A. , ONG LING S. , BAROLD S. SERGE
Published: July 2006

This report describes three cases of inapparent double puncture of the femoral artery and vein as a complication of the transfemoral approach for temporary cardiac pacing. This complication may lead to the passage of a pacing catheter to the right ventricle by way of the femoral artery and vein and may remain undiagnosed until the rigid outer sheath of the introducer set is withdrawn over the pacing catheter. Therefore, we recommend immediate withdrawal of the rigid outer sheath as soon as the catheter lies freely in the iliac vein or the inferior vena cava. If double puncture has occurred, arterial blood will leak around the pacing catheter. Control of arterial bleeding by local compression should not be attempted without removal of the pacing catheter.
Obscure Syncope and the Sick Sinus Syndrome
Authors: LISTER JOHN W. , GOSSELIN ARTHUR J. , SWAYE PAUL S.
Published: July 2006

This report describes a 25‐year‐old vigorous young man who had a history of eight years of near syncope and syncope of unknown etiology. Repeat in‐hospital observation and laboratory electrophysiologic functional testing did not elucidate the origin of the symptoms. Prolonged Holler monitoring finally showed that the syncopal attacks were caused by a sick sinus syndrome (SSS). On electrophysiologic study, a concealed rate‐dependent unidirectional antegrade accessory A‐V pathway (AP) was found to be present. The AP was an incidental finding and was unrelated to the patient's symptoms.

The symptomatic SSS may occur in the young as well as in the elderly. Sinoatrial dysfunction may be intermittent and difficult to detect, may cause severe symptoms, and may even be life‐threatening. Prior to definitive therapy (such as the permanent implantation of a pacemaker), the importance of relating symptoms to a rhythm disturbance has been stressed. In cases where the cause of the symptoms is not obvious, this is best accomplished by continuous Holter monitoring.
Characteristics of Intracardiac Electrograms*
Authors: MYERS GEORGE H. , KRESH YASHA M. , PARSONNET VICTOR
Published: July 2006

Cardiac electrograms were measured on endocardial leads on patients undergoing pacemaker implantation. The data show that small area electrodes reduce R wave amplitude, decrease width of the complex, and increase slopes. The bandwidth of the electrogram increases as the electrode area decreases. The loading of the sensing amplifier changes these characteristics. Distortion is most pronounced for small area electrodes and low lead resistances.
The Automatic Rate Adjustment Pacemaker. The Possibilities of Rate Hysteresis
Authors: PRESTON THOMAS A. , PRESTON ALBERT W.
Published: July 2006

Since the first use of pacemakers there have been attempts to regulate the fixed, or basic rate of implanted pulse generators: Earlier models employed the use of magnets or percutaneous needles to change the pacemaker rate after implantation. A recent development is the programmable pacemaker, which utilizes external electromagnetic signals to alter the basic rate.

A series of engineering advances have resulted in automatic pacemaker rate changes, as first embodied in the hysteresis pacemaker. Notable modifications of the basic hysteresis concept include gradual pacemaker rate changes, and variable hysteresis or rate changes dependent on electrophysiologic events. Many of these technical advances are unknown to physicians; but are disclosed in patents.

In general, negative hysteresis favors emergence of underlying non‐pacer rhythms, whereas positive hysteresis suppresses underlying rhythms of any type. The automatic rate adjustment pacemaker represents an attempt to derive the advantages of negative hysteresis while eliminating the disadvantages of abrupt rate changes. The unit automatically searches for a sinus rhythm slower than the basic pacing rate, by periodically gradually slowing its rate to a lower level.
Symptomatic Sinus Node Disease: Natural History After Permanent Ventricular Pacing*
Authors: SIMON ARTHUR B. , ZLOTO ALLAN E.
Published: July 2006

Fifty‐nine patients between the ages of 13 and 88 with sinus node disease, who received a permanent ventricular pacemaker between 1965 and 1976 at one institution, were followed to determine the natural history of the disorder after permanent pacing. Nineteen had ischemic heart disease, six had primary myocardial disease, and eight valvular heart disease. In 26, no etiology for the arrhythmia was apparent. The one‐ and five‐year survival was 85.5% and 73.1%, respectively. Patients with underlying heart disease had a significantly poorer survival when compared to those without (58% versus 94% at 36 months), and all but 3 of 13 deaths in the first 36 months were in those with ischemic heart disease. There was a distinct trend toward poor survival in those with heart failure prior to pacemaker implant and those over age 65. Patients with sinus bradycardia alone did best (91% survival three years after implant), while those with bradycardia‐tachycardia syndrome and those with sinoatrial arrest alone did distinctly worse (76% and 65% survival at three years, respectively). Twelve of 18 deaths were due to progression of underlying heart disease. The long‐term prognosis with symptomatic sinus node disease can be predicted in part by (1) etiology of the underlying heart disease, (2) pre‐implant arrhythmia, and (3) ventricular function prior to implant. (PACE, Vol. 2, May‐June, 1979)
An Appraisal of Radioisotope Fueled Pacemakers After 5 Years
Authors: PARSONNET VICTOR , MYERS GEORGE H. , MANHARDT MARJORIE
Published: July 2006

Summary and Conclusions

Personal observation of 131 radioisotope‐powered pulse generators in 120 patients over a period of 5 years has confirmed the expectations of the developers. Actuarial survival of the pulse generator at 5 years was 96 percent. There were only two cases of component failure (1.5 percent) and no battery failures.13To date there has been no evident toxicity from radiation effects. The total cost of pacing is less with nuclear units than with lithium or with mercury‐zinc powered models.

Factors, limiting the use of the pacer are the persistence of nonbattery problems that require premature reoperation, and the unavailability of a truly “modern” pulse generator.

Because the nuclear pacers have proved to be effective, relatively inexpensive, and apparently safe, we believe that continued clinical use is justified; the manufacturers, however, should modify the present units by incorporating fully programmable circuits in a pulse generator package much reduced in size.
The Response of Regular Re‐entrant Supraventricular Tachycardia to Right Heart Stimulation
Authors: WARD D.E. , CAMM A.J. , SPURRELL R.A.J.
Published: July 2006

The study was designed to assess the effect of various forms of right atrial or ventricular stimulation on the termination of re‐entrant “supravenlricular” tachycardias. LStandard eleclrophysio‐logical techniques were used in 81 patients to study 86 stable tachycardias. All tachycardias were initiated by single or double atrial or ventricular premature stimuli or incremental atrial pacing. Eight groups of tachycardia circuit were defined in terms of the anterograde and retrograde pathways. Termination of each tachycardia was studied by atrial underdrive, ventricular underdrive. rapid atrial stimulation and single or double atrial and ventricular premature extrastimuli. fntranodal re‐entrant tachycardias formed 33% of the total and WPW tachycardias as a whole formed 55% of the total number of arrhythmias. The remainder were comprised of utrial tachycardia (5%). tachycardias in association with a partial AV nodal bypass (3%) and pre‐excited tachycardias (5%). A single atrial extrastimulus was most effective where the circuit involved the right atrium. Atrial underdrive was consistently Jess successful than a single atrial exlrastimulus in all groups. Rapid atrial pacing was effective in all groups, but caused transient atrial flutter or fibrillation in a proportion of each group except one. Ventricular underdrive stimulation was most effective in those groups where the right ventricle was involved in the circuit, but tended to be less effective than programmed single or double ventricular extrastimuli. Pacemakers designed to deliver appropriately timed single or double extrastimuli may offer an important alternative to other pacing modalities.
Normally Functioning Inhibited Pacemaker Concomitant with Vertebral Nerve Stimulator
Authors: SYLVÉN C. , LEVANDER‐LINDGREN M.
Published: July 2006

Electromagnetic interference is a recognized difficulty in concomitant cordiac pocing and nerve stimulation. A case is reported in which a vertebral nerve slimulator was implanted, with a transmitier anlenna distal to the right nipple. Six months later, intermiltent S‐A block with Adams‐Stokes attacks urgently necessitated cardiac pacing. The ECG lead II showed nerve stimulator potentiais of 0.75 mV. Intracardiac electrogram with unipolar electrode registered potentiais of 0,25 mV, but wilh a bipolar system no such poten‐tials were observed. A bipoiar pacing electrode was therefore implanted, with an in‐hibited pulse generator in the right pectorol area, The system functions without interference from the nerve stimulator. Various aspects of interference are dis‐cussed.