bluuebunny/crossref_metadata_2025 huggingface dataset:
A Preconditioning Mass Matrix to Avoid the Ill-Posed Two-Fluid Model
Authors: Zanotti Angel L. , Méndez Carlos G. , Nigro Norberto M. , Storti Mario
Published: July 2007

Two-fluid models are central to the simulation of transport processes in two-phase homogenized systems. Even though this physical model has been widely accepted, an inherently nonhyperbolic and nonconservative ill-posed problem arises from the mathematical point of view. It has been demonstrated that this drawback occurs even for a very simplified model, i.e., an inviscid model with no interfacial terms. Much effort has been made to remedy this anomaly and in the literature two different types of approaches can be found. On one hand, extra terms with physical origin are added to model the interphase interaction, but even though this methodology seems to be realistic, several extra parameters arise from each added term with the associated difficulty in their estimation. On the other hand, mathematical based-work has been done to find a way to remove the complex eigenvalues obtained with two-fluid model equations. Preconditioned systems, characterized as a projection of the complex eigenvalues over the real axis, may be one of the choices. The aim of this paper is to introduce a simple and novel mathematical strategy based on the application of a preconditioning mass matrix that circumvents the drawback caused by the nonhyperbolic behavior of the original model. Although the mass and momentum conservation equations are modified, the target of this methodology is to present another way to reach a steady-state solution (using a time marching scheme), greatly valued by researchers in industrial process design. Attaining this goal is possible because only the temporal term is affected by the preconditioner. The obtained matrix has two parameters that correct the nonhyperbolic behavior of the model: the first one modifies the eigenvalues removing their imaginary part and the second one recovers the real part of the original eigenvalues. Besides the theoretical development of the preconditioning matrix, several numerical results are presented to show the validity of the method.
Experimental Investigation of Turbine Leakage Flows on the Three-Dimensional Flow Field and Endwall Heat Transfer
Authors: Rehder Hans-Jürgen , Dannhauer Axel
Published: July 2007

Within a European research project, the tip endwall region of low pressure turbine guide vanes with leakage ejection was investigated at DLR in Göttingen. For this purpose a new cascade wind tunnel with three large profiles in the test section and a contoured endwall was designed and built, representing 50% height of a real low pressure turbine stator and simulating the casing flow field of shrouded vanes. The effect of tip leakage flow was simulated by blowing air through a small leakage gap in the endwall just upstream of the vane leading edges. Engine relevant turbulence intensities were adjusted by an active turbulence generator mounted in the test section inlet plane. The experiments were performed with tangential and perpendicular leakage ejection and varying leakage mass flow rates up to 2%. Aerodynamic and thermodynamic measurement techniques were employed. Pressure distribution measurements provided information about the endwall and vane surface pressure field and its variation with leakage flow. Additionally streamline patterns (local shear stress directions) on the walls were detected by oil flow visualization. Downstream traverses with five-hole pyramid type probes allow a survey of the secondary flow behavior in the cascade exit plane. The flow field in the near endwall area downstream of the leakage gap and around the vane leading edges was investigated using a 2D particle image velocimetry system. In order to determine endwall heat transfer distributions, the wall temperatures were measured by an infrared camera system, while heat fluxes at the surfaces were generated with electric operating heating foils. It turned out from the experiments that distinct changes in the secondary flow behavior and endwall heat transfer occur mainly when the leakage mass flow rate is increased from 1% to 2%. Leakage ejection perpendicular to the main flow direction amplifies the secondary flow, in particular the horseshoe vortex, whereas tangential leakage ejection causes a significant reduction of this vortex system. For high leakage mass flow rates the boundary layer flow at the endwall is strongly affected and seems to be highly turbulent, resulting in entirely different heat transfer distributions.
Effects of Bleed Flow on Heat/Mass Transfer in a Rotating Rib-Roughened Channel
Authors: Jeon Yun Heung , Park Suk Hwan , Kim Kyung Min , Lee Dong Hyun , Cho Hyung Hee
Published: July 2007

The present study investigates the effects of bleed flow on heat/mass transfer and pressure drop in a rotating channel with transverse rib turbulators. The hydraulic diameter (Dh) of the square channel is 40.0mm. 20 bleed holes are midway between the rib turburators on the leading surface and the hole diameter (d) is 4.5mm. The square rib turbulators are installed on both leading and trailing surfaces. The rib-to-rib pitch (p) is 10.0 times of the rib height (e) and the rib height-to-hydraulic diameter ratio (e∕Dh) is 0.055. The tests were conducted at various rotation numbers (0, 0.2, 0.4), while the Reynolds number and the rate of bleed flow to main flow were fixed at 10,000 and 10%, respectively. A naphthalene sublimation method was employed to determine the detailed local heat transfer coefficients using the heat/mass transfer analogy. The results suggest that for a rotating ribbed passage with the bleed flow of BR=0.1, the heat/mass transfer on the leading surface is dominantly affected by rib turbulators and the secondary flow induced by rotation rather than bleed flow. The heat/mass transfer on the trailing surface decreases due to the diminution of main flow. The results also show that the friction factor decreases with bleed flow.
A Redundant Parallel Spherical Mechanism for Robotic Wrist Applications
Authors: Hess-Coelho Tarcisio A.
Published: July 2007

Parallel kinematic structures constitute promising alternative architectures, when compared to their serial counterparts, for developing positioning and orienting robotic mechanisms. The present author, in a previous work, proposed a qualitative procedure that enables the designer to compare kinematic structures from a group of candidates for robotic wrist applications. Among one of the architectures recommended by the method—the 3 RRR+RUR—is theoretically analyzed here, so its kinematic performance is evaluated. In order to verify the theoretical results, a prototype of the kinematic parallel structure considered is tested and its behavior is observed under operating conditions.
The case of the oscillating party balloon: A simple toy experiment requiring a not-so-simple interpretation
Authors: Yariv Amnon , Scheuer Jacob , Crosignani Bruno , Di Porto Paolo
Published: July 2007

The intriguing midair oscillations of a party balloon, which occur once its buoyancy is no longer capable of keeping it against the ceiling, is shown to require a rather sophisticated explanation in terms of variable-mass dynamics. The ubiquity of this phenomenon, the accessibility of its actual observation, and the subtlety of its analytic description provide a good opportunity for an interesting zero-cost classroom demonstration.
Radiationless Electromagnetic Interference: Evanescent-Field Lenses and Perfect Focusing
Authors: Merlin R.
Published: July 2007

Diffraction restricts the ability of most electromagnetic devices to image or selectively target objects smaller than the wavelength. We describe planar subwavelength structures capable of focusing well beyond the diffraction limit, operating at arbitrary frequencies. The structure design, related to that of Fresnel plates, forces the input field to converge to a spot on the focal plane. However, unlike the diffraction-limited zone plates, for which focusing results from the interference of traveling waves, the subwavelength plates control the near field and, as such, their superlensing properties originate from a static form of interference. Practical implementations of these plates hold promise for near-field data storage, noncontact sensing, imaging, and nanolithography applications.
Epidemiology of Human Immunodeficiency Virus in the United States
Authors: Hariri Susan , McKenna Matthew T.
Published: July 2007

The human immunodeficiency virus (HIV) epidemic emerged in the early 1980s with HIV infection as a highly lethal disease among men who have sex with men and among frequent recipients of blood product transfusions. Advances in the treatment of HIV infection have resulted in a fundamental shift in its epidemiology, to a potentially chronic and manageable condition. However, challenges in the prevention of this infection remain. In particular, increasing evidence suggests that transmission of drug-resistant virus is becoming more common and that the epidemic is having a profound impact on morbidity and mortality in ethnic and racial minority subgroups in the United States. New population-based data collection systems designed to describe trends in behaviors associated with HIV transmission and better methods for measuring the true incidence of transmission will better elucidate the characteristics of HIV infection in the United States and inform future public health policies.
A major gene for grain cadmium accumulation in oat (Avena sativa L.)
Authors: Tanhuanpää Pirjo , Kalendar Ruslan , Schulman Alan H. , Kiviharju Elina
Published: July 2007

Cadmium (Cd) is a nonessential heavy metal that is highly toxic to living cells at very low concentrations. Most of the Cd in plants derives from soils. Owing to the large amounts consumed, cereals are the major source of dietary Cd, and Cd content in oat can exceed accepted limits. Plants have a set of mechanisms that control the uptake, accumulation, trafficking, and detoxification of Cd and other metals. Genetic factors affect the variation in Cd level between plant species and cultivars, and the development of cultivars that poorly accumulate Cd is a worthwhile goal. Because of the expense of Cd screening, the use of molecular markers linked to low Cd accumulation could be an alternative to phenotyping for selection. In this study, such markers were sought using bulked-segregant analysis in an F2 population from the cross between oat cultivars ‘Aslak’ and ‘Salo’, the second of which is known to be a high Cd accumulator. Four markers associated with grain Cd concentration were found: 2 RAPDs (random amplified polymorphic DNAs), 1 REMAP (retrotransposon-microsatellite amplified polymorphism), and 1 SRAP (sequence-related amplified polymorphism). The first 3 were converted into more reproducible SCAR (sequence-characterized amplified region) markers. The 4 markers were assigned to 1 linkage group that exhibited a QTL (quantitative trait locus) representing a major gene for grain Cd concentration.
Intestinal capacity to digest and absorb carbohydrates is maintained in a rat model of cholestasis
Authors: Leonie Los E. , Wolters Henk , Stellaard Frans , Kuipers Folkert , Verkade Henkjan J. , Rings Edmond H. H. M.
Published: July 2007

Cholestasis is associated with systemic accumulation of bile salts and with deficiency of bile in the intestinal lumen. During the past years bile salts have been identified as signaling molecules that regulate lipid, glucose, and energy metabolism. Bile salts have also been shown to activate signaling routes leading to proliferation, apoptosis, or differentiation. It is unclear, however, whether cholestasis affects the constitution and absorptive capacity of the intestinal epithelium in vivo. We studied small intestinal morphology, proliferation, apoptosis, expression of intestine-specific genes, and carbohydrate absorption in cholestatic (1 wk bile duct ligation), bile-deficient (1 wk bile diversion), and control (sham) rats. Absorptive capacity was assessed by determination of plasma [2H]- and [13C]glucose concentrations after intraduodenal administration of [2H]glucose and naturally enriched [13C]sucrose, respectively. Small intestinal morphology, proliferation, apoptosis, and gene expression of intestinal transcription factors (mRNA levels of Cdx-2, Gata-4, and Hnf-1α, and Cdx-2 protein levels) were similar in cholestatic, bile-deficient, and control rats. The (unlabeled) blood glucose response after intraduodenal administration was delayed in cholestatic animals, but the absorption over 180 min was quantitatively similar between the groups. Plasma concentrations of [2H]glucose and [13C]glucose peaked to similar extents in all groups within 7.5 and 30 min, respectively. Absorption of [2H]glucose and [13C]glucose in plasma was similar in all groups. The present data indicate that neither accumulation of bile salts in the body, nor their intestinal deficiency, two characteristic features of cholestasis, affect rat small intestinal proliferation, differentiation, apoptosis, or its capacity to digest and absorb carbohydrates.
Local vasoconstriction in spinal cord-injured and able-bodied individuals
Authors: Kooijman M. , de Hoog M. , Rongen G. A. , van Kuppevelt H. J. M. , Smits P. , Hopman M. T. E.
Published: July 2007

Local vasoconstriction plays an important role in maintaining blood pressure in spinal cord-injured individuals (SCI). We aimed to unravel the mechanisms of local vasoconstriction [venoarteriolar reflex (VAR) and myogenic response] using both limb dependency and cuff inflation in SCI and compare these with control subjects. Limb blood flow was measured in 11 male SCI (age: 24–55 yr old) and 9 male controls (age: 23–56 yr old) using venous occlusion plethysmography in forearm and calf during three levels of 1) limb dependency, and 2) cuff inflation. During limb dependency, vasoconstriction relies on both the VAR and the myogenic response. During cuff inflation, the decrease in blood flow is caused by the VAR and by a decrease in arteriovenous pressure difference, whereas the myogenic response does not play a role. At the highest level of leg dependency, the percent increase in calf vascular resistance (mean arterial pressure/calf blood flow) was more pronounced in SCI than in controls (SCI 186 ± 53%; controls 51 ± 17%; P = 0.032). In contrast, during cuff inflation, no differences were found between SCI and controls (SCI 17 ± 17%; controls 14 ± 10%). Percent changes in forearm vascular resistance in response to either forearm dependency or forearm cuff inflation were equal in both groups. Thus local vasoconstriction during dependency of the paralyzed leg in SCI is enhanced. The contribution of the VAR to local vasoconstriction does not differ between the groups, since no differences between groups existed for cuff inflation. Therefore, the augmented local vasoconstriction in SCI during leg dependency relies, most likely, on the myogenic response.
Enhanced removal from the plasma of LDL-like nanoemulsion cholesteryl ester in trained men compared with sedentary healthy men
Authors: Vinagre Carmen G. C. , Ficker Elisabeth S. , Finazzo Claudia , Alves Maria J. N. , de Angelis Katia , Irigoyen Maria Claudia , Negrão Carlos E. , Maranhão Raul C.
Published: July 2007

The objective of this study was to evaluate the effects of exercise training on plasma removal of a cholesterol-rich nanoemulsion (LDE) that mimics low-density lipoprotein (LDL) lipid structure and binds to LDL receptors. LDE-derived cholesteryl ester plasma kinetics was studied in 24 exercise-trained and 20 sedentary male subjects. LDE labeled with [14C]cholesteryl ester was injected intravenously, and plasma samples were collected over a 24-h period to determine radioisotope decay curves. LDL cholesterol concentration was similar in both groups. Fractional clearance rate (FCR) of the nanoemulsion label was greater in the exercise-trained group compared with the sedentary group (0.138 ± 0.152 and 0.0261 ± 0.023 h−1, respectively). A positive correlation was found ( r = 0.60, P < 0.01) between FCR and peak O2consumption in trained subjects. Circulating oxidized LDL levels were lower in trained subjects compared with the sedentary group (9.0 ± 2.0 and 16.0 ± 3.0 mU/l). LDE was also injected into control and LDL receptor gene knockout mice submitted and not submitted to training. Muscle LDE uptake percentage was increased in the trained mice compared with the untrained mice (1.1 ± 0.8 and 0.2 ± 0.1, respectively, P < 0.0001) in the control group but not in the knockout animals, indicating that the LDL receptor is involved in the increased uptake elicited by exercise. These results show that exercise training increases LDE plasma removal, which in turn suggests that it also increases LDL receptors or LDL receptor activity.
Predictors of Self-Referral into a Cancer Genetics Registry
Authors: Henrikson Nora Beidler , Harris Julie N. , Bowen Deborah J.
Published: July 2007

Recruitment is a challenging part of developing and maintaining any population-based disease registry and different methods are used to increase enrollment. However, recruitment methods may attract different subgroups of individuals, so examining characteristics of samples recruited using different methods can help detect threats to the external validity of research results.

Objectives: There were two main objectives of this study: to examine differences between participants who were self-referred and those who were recruited into a cancer genetics registry and to identify predictors of self-referral status.

Methods: A cross-sectional survey was done with two groups of cancer genetics registry members (n = 268): (a) members recruited through self-referral and (b) members recruited through population-based sampling.

Results: There were no significant differences in demographic variables between the two samples except for education (higher in the self-referral group; P < 0.01). The self-referral group showed significantly higher levels of anxiety, depression, and cancer history and was more likely to report the strongest response to statements about cancer risk, screening intentions, and views on genetic testing. Logistic regression modeling indicated these predictors of self-referral status: previous cancer diagnosis, viewing self as a candidate for genetic testing, education higher than high school, and wanting assistance with personal future risk (R2 = 0.41).

Conclusions: Our results suggest that whereas groups recruited via different strategies may seem to be the same based on demographic variables, underlying psychosocial variables differ between those self-referring and those recruited via population-based screening. To accurately estimate the generalizability of population-based studies or studies conducted using a cancer genetics registry, method of recruitment should be examined when interpreting and analyzing results. (Cancer Epidemiol Biomarkers Prev 2007;16(7):1387–92)
Smoking and Colorectal Cancer: Different Effects by Type of Cigarettes?
Authors: Lüchtenborg Margreet , White Kami K.L. , Wilkens Lynne , Kolonel Laurence N. , Le Marchand Loïc
Published: July 2007

Although smoking is suggested to be a risk factor for colorectal cancer, the evidence to date is conflicting and may be confounded. Moreover, the effect of tobacco smoke may vary by time since initiation, type of tobacco product, anatomic subsites, and among ethnic groups. Data were derived from two consecutive population-based case-control studies conducted among Caucasians, Japanese, Native Hawaiians, Filipinos, and Chinese in Hawaii, including 1,959 ethnicity-, sex-, and age-matched case-control pairs. A lifetime history of smoking for different tobacco products and information on other risk factors were obtained by in-person interviews. Odds ratios (OR) and corresponding 95% confidence intervals (95% CI) were estimated using conditional logistic regression models with adjustment for potential confounders. Subjects who ever smoked were at an increased risk of colorectal cancer compared with never smokers (OR, 1.23; 95% CI, 0.99-1.52 for men and OR, 1.27; 95% CI, 1.01-1.59 for women). Increasing quartiles of pack-years over all tobacco products showed a clear dose-dependent association in men [for the highest quartile, Q4 (>40 pack-years) versus never smokers: OR, 1.48; 95% CI, 1.12-1.96; Ptrend = 0.002]. The dose-response trend was also present in women [for the highest quartile, Q4 (>30 pack-years) versus never smokers: OR, 1.38; 95% CI, 0.91-1.95; Ptrend = 0.04] and each ethnic group. There was a suggestion of a difference in risk with type of tobacco product. Non-filtered cigarettes increased risk of both colon and rectal cancer [for Q4 versus never smokers: OR, 1.59; 95% CI, 1.15-2.21; Ptrend = 0.001 and OR, 1.84; 95% CI, 1.18-2.86; Ptrend = 0.02, respectively], whereas filtered cigarettes seemed to increase risk of rectal but not colon cancer (OR, 1.37; 95% CI, 0.88-2.13; Ptrend = 0.06 and OR, 1.05; 95% CI, 0.79-1.39; Ptrend = 0.98, respectively). The effect of smoking was not limited to the distant past, and accumulated pack-years of smoking seemed to be more important than the time in which smoking occurred. The data from this large study corroborate previous reports of a positive association between smoking and colorectal cancer and suggest that the association may vary by type of cigarette. (Cancer Epidemiol Biomarkers Prev 2007;16(7):1341–7)
Quantitative Fluorescence Imaging Analysis for Cancer Biomarker Discovery: Application to β-Catenin in Archived Prostate Specimens
Authors: Huang Dali , Casale George P. , Tian Jun , Wehbi Nizar K. , Abrahams Neil A. , Kaleem Zahid , Smith Lynette M. , Johansson Sonny L. , Elkahwaji Johny E. , Hemstreet George P.
Published: July 2007

The surprising disparity between the number of protein-encoding genes (∼30,000) in the human genome and the number of proteins (∼300,000) in the human proteome has inspired the development of translational proteomics aimed at protein expression profiling of disease states. Translational proteomics, which offers the promise of early disease detection and individualized therapy, requires new methods for the analysis of clinical specimens. We have developed quantitative flourescence imaging analysis (QFIA) for accurate, reproducible quantification of proteins in slide-mounted tissues. The method has been validated for the analysis of β-catenin in archived prostate specimens fixed in formalin. QFIA takes advantage of the linearity of fluorescence antibody signaling for tissue epitope content, a feature validated for β-catenin in methacarn-fixed prostate specimens analyzed by reverse-phase protein array analysis and QFIA (r = 0.97). QFIA of β-catenin in formaldehyde-fixed tissues correlated directly with β-catenin content (r = 0.86). Application of QFIA in a cross-sectional study of biopsies from 42 prostate cancer (PC) cases and 42 matched controls identified β-catenin as a potential field marker for PC. Receiver operating characteristic plots revealed that β-catenin expression in the normal-appearing acini of cancerous glands identified 42% (95% confidence intervals, 26-57%) of cancer cases, with 88% (95% confidence intervals, 80-96%) specificity. The marker may contribute to a PC biomarker panel. In conclusion, we report the development and validation of a new method for fluorescence quantification of proteins in archived tissues and its application to archived specimens for an evaluation of β-catenin expression as a biomarker for PC. (Cancer Epidemiol Biomarkers Prev 2007;16(7):1371–81)
A Prospective Study of Polyunsaturated Fatty Acid Levels in Blood and Prostate Cancer Risk
Authors: Chavarro Jorge E. , Stampfer Meir J. , Li Haojie , Campos Hannia , Kurth Tobias , Ma Jing
Published: July 2007

Background: Animal models suggest that n-3 fatty acids inhibit prostate cancer proliferation, whereas n-6 fatty acids promote it, but epidemiologic studies do not uniformly support these findings.

Methods: A nested case-control study was conducted among 14,916 apparently healthy men who provided blood samples in 1982. Blood fatty acid levels were determined for 476 men diagnosed with prostate cancer during a 13-year follow-up and their matched controls. Conditional logistic regression was used to estimate the relative risks (RR) and 95% confidence intervals (95% CI) of total, non-aggressive (stage A/B and Gleason < 7) and aggressive (stage C/D, Gleason ≥ 7, subsequent distant metastasis or death) prostate cancer associated with blood levels of specific fatty acids expressed as percentages of total fatty acids.

Results: Whole blood levels of all long-chain n-3 fatty acids examined and of linoleic acid were inversely related to overall prostate cancer risk (RRQ5vs.Q1, 0.59; 95% CI, 0.38-0.93; Ptrend = 0.01 for total long-chain n-3 fatty acids and RRQ5vs.Q1, 0.62; 95% CI, 0.41-0.95; Ptrend = 0.03 for linoleic). Blood levels of γ-linolenic and dihomo-γ-linolenic acids, fatty acids resulting from the metabolism of linoleic acid, were directly associated with prostate cancer (RR, 1.41; 95% CI, 0.94-2.12; Ptrend = 0.05 for γ-linolenic and RR, 1.54; 95% CI, 1.03-2.30; Ptrend = 0.02 for dihomo-γ-linolenic acid). Levels of arachidonic and α-linolenic acids were unrelated to prostate cancer.

Conclusions: Higher blood levels of long-chain n-3 fatty acids, mainly found in marine foods, and of linoleic acid, mainly found in non-hydrogenated vegetable oils, are associated with a reduced risk of prostate cancer. The direct associations of linoleic acid metabolites with prostate cancer risk deserve further investigation. (Cancer Epidemiol Biomarkers Prev 2007;16(7):1364–70)
Body Mass Index and Mortality among Older Breast Cancer Survivors in the Study of Osteoporotic Fractures
Authors: Reeves Katherine W. , Faulkner Kimberly , Modugno Francesmary , Hillier Teresa A. , Bauer Douglas C. , Ensrud Kristine E. , Cauley Jane A. ,   for the Study of Osteoporotic Fractures Research Group
Published: July 2007

Background: Breast cancer survival is inversely related to body mass index (BMI), but previous studies have not included large numbers of older women. This study investigated the association between BMI and mortality after breast cancer diagnosis in a cohort of older Caucasian women enrolled in the Study of Osteoporotic Fractures.

Methods: All women were age ≥65 at study entry (N = 533). Cox proportional hazards regression analysis was used to determine the effect of BMI as a continuous variable on risk of all-cause, cardiovascular, any cancer, and breast cancer mortality. Interaction terms were included to evaluate effect modification by age at diagnosis.

Results: Mean age at diagnosis was 78.0 years (SD 5.7) with an average of 8.1 years (SD 4.4) of follow-up after diagnosis. There were 206 deaths during follow-up. The effect of BMI on mortality depended on age (Pinteraction = 0.02). At age 65, the risk of mortality was 1.4 times higher for a BMI of 27.3 kg/m2 [95% confidence interval (95% CI), 1.03-2.01] and 2.4 times higher for a BMI of 34.0 kg/m2 (95% CI, 1.07-5.45) compared with women with a BMI of 22.6 kg/m2. At age 85, risk of death was lower for a BMI of 27.3 kg/m2 (hazard ratio, 0.81; 95% CI, 0.65-1.01) or a BMI of 34.0 kg/m2 (hazard ratio, 0.61; 95% CI, 0.36-1.02) compared with a BMI of 22.6 kg/m2. Similar results were observed for any cancer and breast cancer mortality. BMI was not associated with cardiovascular mortality.

Conclusions: In this population of older women, the effect of increased BMI on risk of mortality after breast cancer varied by age. These results differ from those observed among populations of younger postmenopausal breast cancer survivors. (Cancer Epidemiol Biomarkers Prev 2007;16(7):1468–73)
Cholecystectomy and the Risk of Recurrent Colorectal Adenomas
Authors: Vinikoor Lisa C. , Robertson Douglas J. , Baron John A. , Silverman William B. , Sandler Robert S.
Published: July 2007

Prior studies have shown an increased risk of colorectal cancer following cholecystectomy, but few studies have explored the association between cholecystectomy and the risk of colorectal adenomas. We used data from three large randomized adenoma chemoprevention trials to explore the association between cholecystectomy and the occurrence of adenomas. After adjusting for confounding factors, we found no increased risk for adenomas among individuals who had undergone cholecystectomy [risk ratio (RR), 1.02; 95% confidence interval (95% CI), 0.88-1.18]. There was a slight increase in the risk of advanced recurrent adenomas (RR, 1.28; 95% CI, 0.94-1.76) and multiple advanced recurrent adenomas (RR, 1.34; 95% CI, 0.97-1.85) but the 95% CIs included the null in both cases. We conclude that the increased risk for colorectal cancer following cholecystectomy seems to be due to a biological process occurring after the adenoma has developed. (Cancer Epidemiol Biomarkers Prev 2007;16(7):1523–5)
Exacerbation of Albuminuria and Renal Fibrosis in Subtotal Renal Ablation Model of Adiponectin-Knockout Mice
Authors: Ohashi Koji , Iwatani Hirotsugu , Kihara Shinji , Nakagawa Yasuhiko , Komura Noriyuki , Fujita Koichi , Maeda Norikazu , Nishida Makoto , Katsube Fumie , Shimomura Iichiro , Ito Takahito , Funahashi Tohru
Published: July 2007

Objective—

Obesity is recognized increasingly as a major risk factor for kidney disease. We reported previously that plasma adiponectin levels were decreased in obesity, and that adiponectin had defensive properties against type 2 diabetes and hypertension. In this study, we investigated the role of adiponectin for kidney disease in a subtotal nephrectomized mouse model.

Methods and Results—

Subtotal (5/6) nephrectomy was performed in adiponectin-knockout (APN-KO) and wild-type (WT) mice. The procedure resulted in significant accumulation of adiponectin in glomeruli and interstitium in the remnant kidney. Urinary albumin excretion, glomerular hypertrophy, and tubulointerstitial fibrosis were significantly worse in APN-KO mice compared with WT mice. Intraglomerular macrophage infiltration and mRNA levels of vascular cell adhesion molecule (VCAM)-1, MCP-1, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, collagen type I/III, and NADPH oxidase components were significantly increased in KO mice compared with WT mice. Treatment of APN-KO mice with adenovirus-mediated adiponectin resulted in amelioration of albuminuria, glomerular hypertrophy, and tubulointerstitial fibrosis and reduced the elevated levels of VCAM-1, MCP-1, TNF-α, TGF-β1, collagen type I/III, and NADPH oxidase components mRNAs to the same levels as those in WT mice.

Conclusions—

Adiponectin accumulates to the injured kidney, and prevents glomerular and tubulointerstitial injury through modulating inflammation and oxidative stress.
Functional Rescue of Elastin Insufficiency in Mice by the Human Elastin Gene
Authors: Hirano Eiichi , Knutsen Russell H. , Sugitani Hideki , Ciliberto Christopher H. , Mecham Robert P.
Published: July 2007

Diseases linked to the elastin gene arise from loss-of-function mutations leading to protein insufficiency (supravalvular aortic stenosis) or from missense mutations that alter the properties of the elastin protein (dominant cutis laxa). Modeling these diseases in mice is problematic because of structural differences between the human and mouse genes. To address this problem, we developed a humanized elastin mouse with elastin production being controlled by the human elastin gene in a bacterial artificial chromosome. The temporal and spatial expression pattern of the human transgene mirrors the endogenous murine gene, and the human gene accurately recapitulates the alternative-splicing pattern found in humans. Human elastin protein interacts with mouse elastin to form functional elastic fibers and when expressed in the elastin haploinsufficient background reverses the hypertension and cardiovascular changes associated with that phenotype. Elastin from the human transgene also rescues the perinatal lethality associated with the null phenotype. The results of this study confirm that reestablishing normal elastin levels is a logical objective for treating diseases of elastin insufficiency such as supravalvular aortic stenosis. This study also illustrates how differences in gene structure and alternative splicing present unique problems for modeling human diseases in mice.
The Group as a Resource: Reducing Biased Attributions for Group Success and Failure via Group Affirmation
Authors: Sherman David K. , Kinias Zoe , Major Brenda , Kim Heejung S. , Prenovost Mary
Published: July 2007

Self-affirmation theory proposes that people can respond to threats to the self by affirming alternative sources of self-integrity, resulting in greater openness to self-threatening information. The present research examines this at a group level by investigating whether a group affirmation (affirming an important group value) increases acceptance of threatening group information among sports teams and fans. In Study 1, athletes exhibited a group-serving attributional bias, which was eliminated by the group affirmation. In Study 2, the most highly identified fans exhibited the most bias in terms of their attributions, and this bias was eliminated by the group affirmation. These studies suggest that groups can serve as resources from which people can draw in response to threatening group events.
Development of a New Measurement Tool for Individualism and Collectivism
Authors: Shulruf Boaz , Hattie John , Dixon Robyn
Published: July 2007

A new measurement tool for individualism and collectivism has been developed to address critical methodological issues in this field of social psychology. This new measure, the Auckland Individualism and Collectivism Scale (AICS), defines three dimensions of individualism: (a) responsibility (acknowledging one's responsibility for one's actions), (b) uniqueness (distinction of the self from the other), and (c) competitiveness (striving for personal goals is one's prime interest). The scale also defines two dimensions of collectivism: (a) advice (seeking advice from people close to one, before taking decisions) and (b) harmony (seeking to avoid conflict). The AICS avoids the need for measuring horizontal and vertical dimensions of collectivism and individualism and the confounding effect of familialism on the collectivism—individualism constructs.
Effects of an open-label pilot study with high-dose EPA/DHA concentrates on plasma phospholipids and behavior in children with attention deficit hyperactivity disorder
Authors: Sorgi Paul J , Hallowell Edward M , Hutchins Heather L , Sears Barry
Published: July 2007

Background

Attention deficit hyperactivity disorder (ADHD) is the most common neurological condition in children. This pilot study evaluated the effects of high-dose eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on the isolated plasma phospholipids and behavior in children with ADHD (primarily inattentive subtype and combined subtype).

Methods

Nine children were initially supplemented with 16.2 g EPA/DHA concentrates per day. The dosage was adjusted dependent on the ratio of arachidonic acid (AA) to EPA in the isolated plasma phospholipids at four weeks to reach a level normally found in the Japanese population.

Results

At the end of the eight-week study, supplementation resulted in significant increases in EPA and DHA, as well as a significant reduction in the AA:EPA ratio (20.78 ± 5.26 to 5.95 ± 7.35, p < 0.01). A psychiatrist (blind to supplement compliance or dosage modifications) reported significant improvements in behavior (inattention, hyperactivity, oppositional/defiant behavior, and conduct disorder). There was also a significant correlation between the reduction in the AA:EPA ratio and global severity of illness scores.

Conclusion

The findings of this small pilot study suggest supplementation with high-dose EPA/DHA concentrates may improve behavior in children with ADHD.
Human Chorionic Gonadotropin Produced by the Invasive Trophoblast But Not the Villous Trophoblast Promotes Cell Invasion and Is Down-Regulated by Peroxisome Proliferator-Activated Receptor-γ
Authors: Handschuh Karen , Guibourdenche Jean , Tsatsaris Vassilis , Guesnon Mickaël , Laurendeau Ingrid , Evain-Brion Danièle , Fournier Thierry
Published: July 2007

A critical step in the establishment of human pregnancy is the invasion of the uterus wall by extravillous cytotrophoblasts (EVCTs) during the first trimester. It is well established that human chorionic gonadotropin hormone (hCG) is secreted by the endocrine syncytiotrophoblast (ST) into the maternal compartment. We recently reported that invasive EVCTs also produce hCG, suggesting an autocrine role in the modulation of trophoblast invasion. Here we analyzed the role of hCG secreted in vitro by primary cultures of invasive EVCT and noninvasive ST. We first demonstrated that LH/CG receptor was present in EVCTs in situ and in vitro as well as in an EVCT cell line (HIPEC65). We next showed that hCG secreted by EVCTs stimulated progesterone secretion by MA10 cells in a concentration-dependent manner. Incubation of HIPEC65 with EVCT supernatants induced a 10-fold increase in cell invasion, whereas ST supernatants had no effect. This stimulating effect was strongly decreased when hCG was depleted from EVCT supernatants containing a large amount of the hyperglycosylated form of hCG, which is almost undetectable in ST supernatants. Finally, we investigated the regulation of hCG expression by peroxisome proliferator-activated receptor (PPAR)-γ, a nuclear receptor shown to inhibit trophoblast invasion. Activation of PPARγ decreased α- and β-subunit transcript levels and total hCG secretion in primary EVCTs. Our results offer the first evidence that hCG secreted by the invasive trophoblast, likely the hyperglycosylated form of hCG, but not by the syncytiotrophoblast, promotes trophoblast invasion and may be a PPARγ target gene in trophoblast invasion process.
The effect of cryosurgery on the canine and human larynx
Authors: Hong Soo Wung , Silverstein Herbert , Sadeghee Saeed
Published: July 2007

The effect of cryosurgery with the Brymill laryngeal spray was studied in 14 canine larynges. The liquid nitrogen spray was applied via a laryngo fissure or through the Jako suspension laryngoscope. Tissue temperatures were recorded with a thermocouple. The effects of liquid nitrogen spray on canine laryngeal tissues to determine the amount of tissue which can be destroyed, while preserving normal laryngeal function, were studied.

The results of the treatment of four patients with the laryngeal cryosurgery are presented.
Five hundred cancers of the larynx and pyriform sinus: Results of treatment by radiation and surgery
Authors: Kirchner John A. , Owen James R.
Published: July 2007

Three hundred eighty cancers of the larynx and 120 of the pyriform sinus were treated in the 15 years from 1958‐1973 at Yale‐New Haven Hospital. They were studied for response to treatment by surgery, radiation or a combination of the two. Overall control rates in the entire group of 500 were 51% for radiotherapy, 51% for surgery. Further analysis showed significant differences in the results obtained by stage and by location for surgery and radiotherapy. The total number of cases treated by combined therapy was relatively small, except for pyriform sinus.

Radiotherapy success showed a steep gradient from 82% in Tl lesions to 5% in T4. The gradient for surgery was less steep with 64% success for Tl and 40% for T4. Both radiotherapy and surgery were most successful in glottic cancer and least successful in the pyriform sinus. However, the success range varied more with radiation than with surgery (83% success in glottic cancer, 5% in pyriform sinus cancer for radiotherapy; 81% in glottic cancer and 24% in pyriform sinus for surgery). Late primary recurrences (3 years or more after radiation therapy) developed only in the glottic group.

Recurrent cancer at the primary site in non‐glottic lesions appeared within 2 years after radiotherapy in 65 of the 66 local recurrences. Similarly, 77 of the 82 local recurrences of non‐glottic cancer after surgery appeared within 2 years.

With only 1 exception in 34 cases, surgical salvage of radiation failures succeeded only in glottic cancer.

Of the 136 T1 glottic lesions there were no discernible regional metas‐tases. In the remaining 73 glottic T2 and T3 lesions, cervical node me‐tastases developed in 8 lesions.

Supraglottic cancer was the most likely to produce cervical node metastasis from an early primary lesion (5 Tl lesions among 10 supraglottic lesions with unrecognized positive nodes).

Eight of the 65 patients with fixed cervical node metastasis were controlled with no evidence of disease after 3 years.

Among the treatment failures, most of those in the radiotherapy group were due to uncontrolled primary disease (72%). The failures among the surgical group were due mainly to metastasis (72%).

Final controls obtained by surgery, radiotherapy, combined treatment and secondary salvage of radiation or surgical failures were as follows: glottic 82%; supraglottic 58%; transglottic 58%; subglottic 60%; pyriform sinus 17%.
The effect of tracheostomy on the laryngeal closure reflex
Authors: Sasaki Clarence T. , Suzuki Masafumi , Horiuchi Masatoshi , Kirchner John A.
Published: July 2007

The clinical observation of aspiration following prolonged tracheostomy prompted a neurophysiologic investigation of the glottic closure reflex in dogs longitudinally evaluated after permanent tracheostomy. The data support significant alterations in the central organization of the protective closure reflex heretofore considered phylogenetically primitive and therefore physiologically stable over wide ranges of functional demand. The data indicate that chronic upper airway bypass results in: 1. increased threshold of the evoked adductor response; 2. random shifts in its latency; 3. rapid attenuation of the primary evoked response to repetitive SLN stimulation; and U. reduced after‐discharge activity, all of which contribute to a weakened, ill‐coordinated closure response.
Central auditory imperception
Authors: Snow James B. , Rintelmann William F. , Miller Josef M. , Konkle Dan F.
Published: July 2007

The development of clinically applicable techniques for the evaluation of hearing impairment caused by lesions of the central auditory pathways has increased clinical interest in the anatomy and physiology of these pathways. A conceptualization of present understanding of the anatomy and physiology of the central auditory pathways is presented.

Clinical tests based on reduction of redundancy of the speech message, degradation of speech and binaural interactions are presented. Specifically performance‐intensity functions, filtered speech tests, competing message tests and time‐compressed speech tests are presented with the emphasis on our experience with time‐compressed speech tests. With proper use of these tests not only can central auditory impairments be detected, but brain stem lesions can be distinguished from cortical lesions.
Acinic cell tumors of salivary gland origin
Authors: Clemis Jack D. , Bland James , Fung Christopher
Published: July 2007

The acinic cell tumor of salivary gland origin, once thought to be benign, is now known to be an incidiously slow growing malignant neoplasm with lethal potential. While the degree of malignant behavior of individual acinic cell tumors is notably variable, all must be treated with aggression. Traditional and current methods of treatment are reviewed; and, in conjunction with the tumors herein reported, guidelines for management of this uncommon malignancy are suggested. Four cases have been reviewed in detail and critically analyzed. The pathology, including features of both light and electron microscopy, is included‐particularly in relation to the oncocytoid areas identified in from 10% to 40% of the parenchymal cells of our tumors. Since an accurate histopathologic diagnosis is the first step in the establishment of a proper treatment plan, pitfalls in histologie diagnosis have been stressed.
Composite resection in the elderly: A well‐tolerated procedure
Authors: Johnson Jonas T. , Rabuzzi Daniel D. , Tucker Harvey M.
Published: July 2007

The advisability of surgery in the elderly must be weighed against continued nonoperative care. The gloomy prospects of the patient with uncontrolled carcinoma of the head and neck led to the development and wide application of the composite resection for control of carcinoma of the oral cavity. The risks involved in this major undertaking in the elderly have not been previously reported.

To this end a retrospective study of charts of patients over the age of 64 were reviewed and complications categorized. A representative group of younger patients were similarly reviewed for comparison.

Wound complication rates were similar in the two groups, however the elderly were more likely to suffer associated medical problems which tended to be of a more serious nature.

An overall complication rate of 29% was encountered with a mortality of 4%.
Middle ear effusions in neonates
Authors: Balkany Thomas J. , Berman Steven A. , Simmons Michael A. , Jafek Bruce W.
Published: July 2007

Suppurative middle ear effusions (MEE) have been shown to occur commonly in neonates. In spite of this, otoscopy is not routinely performed on septic infants in the neonatal intensive care unit (ICU). This is clinically significant since unrecognized suppurative MEE may act as a focus for dissemination of bacteria into the circulation and/or central nervous system (CNS).

We have completed a prospective study in an attempt to define the prevalence, bacteriology, and response to therapy of MEE in neonates. To facilitate this, the normal micro‐otoscopic appearance of the newborn TM was established by systematically examining 50 normal infants under 24 hours old.

MEE was present in 30% of 125 consecutively examined infants in the neonatal ICU. Bacteriologic data are drawn from tympanocentesis performed on 34 neonates. Nasotracheal intubation of longer than seven days is highly associated with suppurative MEE. Suppurative MEE in the neonatal ICU is often refactory to treatment and may require prolonged therapy and repeated tympanocentesis.
Deficient cell‐mediated immunity in head and neck cancer patients secondary to autologous suppressive immune cells
Authors: Berlingek Norman T. , Hilal Elias Y. , Oettgen Herbert F. , Good Robert A.
Published: July 2007

Fifty‐four patients with epidermoid head and neck cancer were studied with routine and modified mixed leukocyte culture (MLC) techniques to quantify and characterize their cell‐mediated immunity (CMI). Of these, 67% demonstrated deficient CMI in MLC. Employing G&10 column filtration to remove adherent cells selectively, the authors found that 56% of these deficient individuals demonstrated significantly increased lymphocyte responsiveness in MLC. Returning the adherent cells to the cultures usually recaptured the suppressive effect of these adherent cells. Cell marker analyses reveal that the macrophage is the most likely candidate for this suppressive cell. Therapeutic measures which address this paradoxically suppressive cell could be of benefit in enhancing CMI and gaining tumor control.
Acute epiglottitis: Intubation versus tracheostomy.
Authors: Cantrell Robert W. , Bell Roger A. , Morioka Wilfred T.
Published: July 2007

Acute epiglottitis is a disease with significant mortality. The patient, usually an otherwise healthy pre‐school child, develops a sore throat and muffled voice from swollen supraglottic structures, and may progress rapidly to respiratory arrest. Early diagnosis and airway maintenance can prevent these fatalities. Whether to secure an airway by tracheostomy or endotracheal intubation is the subject of much discussion.

Nineteen series totalling 738 cases of epiglottitis plus 11 new cases are reviewed. These patients were treated as follows: Tracheostomy = 348 (3 deaths ‐ 0.86%); Endotracheal intubation = 216 (2 deaths ‐ 0.92%); Medical management with no artificial airway = 214 (13 deaths ‐ 6.1%). The difference in morbidity and mortality between tracheostomy or nasotracheal intubation is so slight that the choice should be determined by local factors.

Medical management with no artificial airway should not be used in children.