bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidant and redox signaling in vascular oxygen sensing mechanisms: basic concepts, current controversies, and potential importance of cytosolic NADPH
Authors: Wolin Michael S. , Ahmad Mansoor , Gupte Sachin A.
Published: July 2005

Vascular smooth muscle (VSM) derived from pulmonary arteries generally contract to hypoxia, whereas VSM from systemic arteries usually relax, indicating the presence of basic oxygen-sensing mechanisms in VSM that are adapted to the environment from which they are derived. This review considers how fundamental processes associated with the generation of reactive oxygen species (ROS) by oxidase enzymes, the metabolic control of cytosolic NADH, NADPH and glutathione redox systems, and mitochondrial function interact with signaling systems regulating vascular force in a manner that is potentially adapted to be involved in Po2sensing. Evidence for opposing hypotheses of hypoxia, either decreasing or increasing mitochondrial ROS, is considered together with the Po2dependence of ROS production by Nox oxidases as sensors potentially contributing to hypoxic pulmonary vasoconstriction. Processes through which ROS and NAD(P)H redox changes potentially control interactive signaling systems, including soluble guanylate cyclase, potassium channels, and intracellular calcium are discussed together with the data supporting their regulation by redox in responses to hypoxia. Evidence for hypothesized potential differences between systemic and pulmonary arteries originating from properties of mitochondrial ROS generation and the redox sensitivity of potassium channels is compared with a new hypothesis in which differences in the control of cytosolic NADPH redox by the pentose phosphate pathway results in increased NADPH and Nox oxidase-derived ROS in pulmonary arteries, whereas lower levels of glucose-6-phosphate dehydrogenase in coronary arteries may permit hypoxia to activate a vasodilator mechanism controlled by oxidation of cytosolic NADPH.
Carbon monoxide inhibits IL-17-induced IL-6 production through the MAPK pathway in human pulmonary epithelial cells
Authors: Ning Wen , Choi Augustine M. K. , Li Chaojun
Published: July 2005

Interleukin (IL)-17 is a proinflammatory cytokine that is produced by activated memory CD4 T cells, which regulates pulmonary neutrophil emigration by the induction of CXC chemokines and cytokines. IL-17 constitutes a potential target for pharmacotherapy against exaggerated neutrophil recruitment in airway diseases. As a cytoprotective and anti-inflammatory gaseous molecule, carbon monoxide (CO) may also regulate IL-17-induced inflammatory responses in pulmonary cells. Herein, we examine the production of cytokine IL-6 induced by IL-17 and the effect of CO on IL-17-induced IL-6 production in human pulmonary epithelial cell A549. We first show that IL-17 can induce A549 cells to release IL-6 and that CO can markedly inhibit IL-17-induced IL-6 production. IL-17 activated the ERK1/2 MAPK pathway but did not affect p38 and JNK MAPK pathways. CO exposure selectively attenuated IL-17-induced ERK1/ERK2 MAPK activation without significantly affecting either JNK or p38 MAPK activation. Furthermore, in the presence of U0126 and PD-98059, selective inhibitors of MEK1/2, IL-17-induced IL-6 production was significantly attenuated. We conclude that CO inhibits IL-17-stimulated inflammatory response via the ERK1/2-dependent pathway.
Role of PKC in the regulation of gonadotropin subunit mRNA levels: interaction with two native forms of gonadotropin-releasing hormone
Authors: Klausen Christian , Severson David L. , Chang John P. , Habibi Hamid R.
Published: July 2005

Gonadotropin-releasing hormone (GnRH) is an important regulator of reproduction in all vertebrates through its actions on the production and secretion of pituitary gonadotropin hormones (GtHs). Most vertebrate species express at least two GnRHs, including one form, designated chicken (c)GnRH-II or type II GnRH, which has been well conserved throughout evolution. The goldfish brain and pituitary contain salmon GnRH and cGnRH-II. In goldfish, GnRH-induced luteinizing hormone (LH) secretion involves PKC; however, whether PKC mediates GnRH stimulation of GtH subunit mRNA levels is unknown. In this study, we used inhibitors and activators of PKC to examine its possible involvement in GnRH-induced increases in GtH-α, follicle-stimulating hormone (FSH)-β and LH-β mRNA levels in primary cultures of dispersed goldfish pituitary cells. Treatment with PKC inhibitors calphostin C and GF109203X unmasked a basal repression of GtH subunit mRNA levels by PKC; both inhibitors increased GtH subunit mRNA levels in a dose-dependent manner. PKC activators, 12- O-tetradecanoylphorbol 13-acetate (TPA), and 1,2-dioctanoyl- sn-glycerol, stimulated GtH subunit mRNA levels, whereas an inactive phorbol ester (4-α-TPA) was without effect. Thus, a dual, inhibitory and stimulatory, influence for PKC in the regulation of GtH subunit mRNA levels is suggested. In contrast, PKC inhibitor- and activator-induced effects were, for the most part, additive to those of GnRH, suggesting that conventional and novel PKCs are unlikely to be involved in GnRH-stimulated increases in GtH subunit mRNA levels. Our data illustrate major differences in the signal transduction of GnRH effects on GtH secretion and gene expression in the goldfish pituitary.
Deficiency of α-sarcoglycan differently affects fast- and slow-twitch skeletal muscles
Authors: Danieli-Betto Daniela , Esposito Alessandra , Germinario Elena , Sandonà Dorianna , Martinello Tiziana , Jakubiec-Puka Anna , Biral Donatella , Betto Romeo
Published: July 2005

α-Sarcoglycan (Sgca) is a transmembrane glycoprotein of the dystrophin complex located at skeletal and cardiac muscle sarcolemma. Defects in the α-sarcoglycan gene ( Sgca) cause the severe human-type 2D limb girdle muscular dystrophy. Because Sgca-null mice develop progressive muscular dystrophy similar to human disorder they are a valuable animal model for investigating the physiopathology of the disorder. In this study, biochemical and functional properties of fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus muscles of the Sgca-null mice were analyzed. EDL muscle of Sgca-null mice showed twitch and tetanic kinetics comparable with those of wild-type controls. In contrast, soleus muscle showed reduction of twitch half-relaxation time, prolongation of tetanic half-relaxation time, and increase of maximal rate of rise of tetanus. EDL muscle of Sgca-null mice demonstrated a marked reduction of specific twitch and tetanic tensions and a higher resistance to fatigue compared with controls, changes that were not evident in dystrophic soleus. Contrary to EDL fibers, soleus muscle fibers of Sgca-null mice distinctively showed right shift of the pCa-tension (pCa is the negative log of Ca2+ concentration) relationships and reduced sensitivity to caffeine of sarcoplasmic reticulum. Both EDL and soleus muscles showed striking changes in myosin heavy-chain (MHC) isoform composition, whereas EDL showed a larger number of hybrid fibers than soleus. In contrast to the EDL, soleus muscle of Sgca-null mice contained a higher number of regenerating fibers and thus higher levels of embryonic MHC. In conclusion, this study revealed profound distinctive biochemical and physiological modifications in fast- and slow-twitch muscles resulting from α-sarcoglycan deficiency.
Disruption of glomerular cell-cell and cell-matrix interactions in hydrocarbon nephropathy
Authors: Nanez Adrian , Alejandro Napoleon F. , Falahatpisheh M. Hadi , Kerzee J. Kevin , Roths John B. , Ramos Kenneth S.
Published: July 2005

Environmental chemicals play an etiological role in greater than 50% of idiopathic glomerular diseases. The present studies were conducted to define mechanisms of renal cell-specific hydrocarbon injury. Female rats were given 10 mg/kg benzo(a)pyrene (BaP) once a week for 16 wk. Progressive elevations in total urinary protein, protein/creatinine ratios, and microalbuminuria were observed in rats treated with BaP for up to 16 wk. The nephropathic response involved early reductions in mesangial cell numbers and fibronectin levels by 8 wk, coupled to transient increases in podocyte cellularity. Changes in podocyte numbers subsided by 16 wk and correlated with rebound increases in mesangial cell numbers and fibronectin levels, along with increased α-smooth muscle actin and Cu/Zn superoxide dismutase and fusion of podocyte foot processes. In culture, mesangial cells were more sensitive than podocytes to hydrocarbon injury and expressed higher levels of inducible aryl hydrocarbon hydroxylase activity. Naïve mesangial cells exerted a strong inhibitory influence on podocyte proliferation under both direct and indirect coculture conditions, and this response involved a mesangial cell-derived matrix that selectively inhibited podocyte proliferation. These findings indicate that hydrocarbon nephropathy in rats involves disruption of glomerular cell-cell and cell-matrix interactions mediated by deposition of a mesangial cell-derived growth-inhibitory matrix that regulates podocyte proliferation.
Insights into the mechanisms of renal fibrosis: is it possible to achieve regression?
Authors: Chatziantoniou Christos , Dussaule Jean-Claude
Published: July 2005

Recent evidence suggests that the progression of renal fibrosis is a reversible process, at least in experimental models. The present review summarizes the new insights concerning the mechanisms of progression and regression of renal disease and examines this novel evidence under the light of feasibility and transfer to human nephropathies. The involved mechanisms are discussed with particular emphasis on the fibrotic role of vasoactive peptides such as angiotensin II and endothelin and growth factors such as transforming growth factor (TGF)-β. The possibility of regression is introduced by presenting the in vivo efficiency of antihypertensive treatments and of systems that antagonize the fibrogenic action of TGF-β such as bone morphogenic protein-7 and HGF. Finally, we provide a brief description of the promising future directions and clinical considerations about the applications of the experimental data to humans.
Prostacyclin signaling in the kidney: implications for health and disease
Authors: Nasrallah Rania , Hébert Richard L.
Published: July 2005

The balance between vasodilator and vasoconstrictor pathways is key to the maintenance of homeostasis and the outcome of disease. In the kidney, prostaglandins (PGs) uphold this balance and regulate renal function: hemodynamics, renin secretion, growth responses, tubular transport processes, and cell fate. With the advent of cyclooxygenase (COX)-2-selective inhibitors, targeted deletions in mice (COX knockouts, PG receptor knockouts), and the discovery of intracrine signaling options for PGs (peroxisome proliferator-activated receptors and perinuclear PGE2receptors: EP1,3,4), many advances have been made in the study of arachidonic acid metabolites. Although prostacyclin (PGI2) is a major product of the COX pathway, there is very little emphasis on its importance to the kidney. This review will discuss PGI2biology and its relevance to different aspects of renal disease (growth, fibrosis, apoptosis), highlighting the most significant research from the past decade of PGI2literature, what we have learned from other organ systems, while stressing the significance of cross talk between various PGI2signaling pathways and its implications for renal health and disease.
Relationship between force and stiffness in muscle fibers after stretch
Authors: Rassier Dilson E. , Herzog Walter
Published: July 2005

The purpose of this study was to evaluate the relationship between force and stiffness after stretch of activated fibers, while simultaneously changing contractility by interfering with the cross-bridge kinetics and muscle activation. Single fibers dissected from lumbrical muscles of frogs were placed at a length 20% longer than the plateau of the force-length relationship, activated, and stretched by 5 and 10% of fiber length (speed: 40% fiber length/s). Experiments were conducted with maximal and submaximal stimulation in Ringer solution and with the addition of 2 and 5 mM of the myosin inhibitor 2,3-butanedione monoxime (BDM) to the solution. The steady-state force after stretch of an activated fiber was higher than the isometric force produced at the corresponding length in all conditions investigated. Lowering the frequency of stimulation decreased the force and stiffness during isometric contractions, but it did not change force enhancement and stiffness enhancement after stretch. Administration of BDM decreased the force and stiffness during isometric contractions, but it increased the force enhancement and stiffness enhancement after stretch. The relationship between force enhancement and stiffness suggests that the increase in force after stretch may be caused by an increase in the proportion of cross bridges attached to actin. Because BDM places cross bridges in a weakly bound, pre-powerstroke state, our results further suggest that force enhancement is partially associated with a recruitment of weakly bound cross bridges into a strongly bound state.
Inactivity, exercise, and visceral fat. STRRIDE: a randomized, controlled study of exercise intensity and amount
Authors: Slentz Cris A. , Aiken Lori B. , Houmard Joseph A. , Bales Connie W. , Johnson Johanna L. , Tanner Charles J. , Duscha Brian D. , Kraus William E.
Published: July 2005

Despite the importance of randomized, dose-response studies for proper evaluation of effective clinical interventions, there have been no dose-response studies on the effects of exercise amount on abdominal obesity, a major risk factor for metabolic syndrome, diabetes, and cardiovascular disease. One hundred seventy-five sedentary, overweight men and women with mild to moderate dyslipidemia were randomly assigned to participate for 6 mo in a control group or for ∼8 mo in one of three exercise groups: 1) low amount, moderate intensity, equivalent to walking 12 miles/wk (19.2 km) at 40–55% of peak oxygen consumption; 2) low amount, vigorous intensity, equivalent to jogging 12 miles/wk at 65–80% of peak oxygen consumption; or 3) high amount, vigorous intensity, equivalent to jogging 20 miles/wk (32.0 km). Computed tomography scans were analyzed for abdominal fat. Controls gained visceral fat (8.6 ± 17.2%; P = 0.001). The equivalent of 11 miles of exercise per week, at either intensity, prevented significant accumulation of visceral fat. The highest amount of exercise resulted in decreased visceral (−6.9 ± 20.8%; P = 0.038) and subcutaneous (−7.0 ± 10.8%; P < 0.001) abdominal fat. Significant gains in visceral fat over only 6 mo emphasize the high cost of continued inactivity. A modest exercise program, consistent with recommendations from the Centers for Disease Control/American College of Sports Medicine (CDC/ACSM), prevented significant increases in visceral fat. Importantly, a modest increase over the CDC/ACSM exercise recommendations resulted in significant decreases in visceral, subcutaneous, and total abdominal fat without changes in caloric intake.
NaHCO3-induced alkalosis reduces the phosphocreatine slow component during heavy-intensity forearm exercise
Authors: Forbes S. C. , Raymer G. H. , Kowalchuk J. M. , Marsh G. D.
Published: July 2005

During heavy-intensity exercise, the mechanisms responsible for the continued slow decline in phosphocreatine concentration ([PCr]) (PCr slow component) have not been established. In this study, we tested the hypothesis that a reduced intracellular acidosis would result in a greater oxidative flux and, consequently, a reduced magnitude of the PCr slow component. Subjects ( n = 10) performed isotonic wrist flexion in a control trial and in an induced alkalosis (Alk) trial (0.3g/kg oral dose of NaHCO3, 90 min before testing). Wrist flexion, at a contraction rate of 0.5 Hz, was performed for 9 min at moderate- (75% of onset of acidosis; intracellular pH threshold) and heavy-intensity (125% intracellular pH threshold) exercise.31P-magnetic resonance spectroscopy was used to measure intracellular [H+], [PCr], [Pi], and [ATP]. The initial recovery data were used to estimate the rate of ATP synthesis and oxidative flux at the end of heavy-intensity exercise. In repeated trials, venous blood sampling was used to measure plasma [H+], [HCO3−], and [Lac−]. Throughout rest and exercise, plasma [H+] was lower ( P < 0.05) and [HCO3−] was elevated ( P < 0.05) in Alk compared with control. During the final 3 min of heavy-intensity exercise, Alk caused a lower ( P < 0.05) intracellular [H+] [246 (SD 117) vs. 291 nmol/l (SD 129)], a greater ( P < 0.05) [PCr] [12.7 (SD 7.0) vs. 9.9 mmol/l (SD 6.0)], and a reduced accumulation of [ADP] [0.065 (SD 0.031) vs. 0.098 mmol/l (SD 0.059)]. Oxidative flux was similar ( P > 0.05) in the conditions at the end of heavy-intensity exercise. In conclusion, our results are consistent with a reduced intracellular acidosis, causing a decrease in the magnitude of the PCr slow component. The decreased PCr slow component in Alk did not appear to be due to an elevated oxidative flux.
Effects of moderate-velocity strength training on peak muscle power and movement velocity: do women respond differently than men?
Authors: Delmonico Matthew J. , Kostek Matthew C. , Doldo Neil A. , Hand Brian D. , Bailey Jason A. , Rabon-Stith Karma M. , Conway Joan M. , Carignan Craig R. , Lang Jesse , Hurley Ben F.
Published: July 2005

The effects of a 10-wk unilateral knee extension strength training (ST) program on peak power (PP) and peak movement velocity (PV), at given absolute (force load) and relative (same % of 1 repetition maximum) resistances (loads), were examined in 30 older men [64 yr (7 SD)] and 32 older women [62 yr (6 SD)]. PP increased significantly in both men and women at the same absolute ( P < 0.001) and relative loads ( P < 0.01) with ST. Men had a significantly greater increase in relative PP than women with ST at 60% ( P < 0.01) and 70% ( P < 0.001) of 1 repetition maximum when covarying for baseline differences and age. However, when each subject was tested at the same absolute load and when PP was normalized for the muscle volume of the trained knee extensors (i.e., absolute muscle power quality), women increased by 9% ( P < 0.05), whereas men did not change. Both men and women increased their absolute PV ( P < 0.001) but decreased their relative PV significantly with ST ( P < 0.05). However, when baseline values and age were covaried, women had significantly less of a decrease in relative PV quality with ST than men ( P < 0.01), although the difference was small. These normalized data suggest that ST-induced increases in PP depend on muscular hypertrophy in men, but not in women, providing further support for the hypothesis developed from our previous report (Ivey FM, Tracy BL, Lemmer JT, NessAiver M, Metter EJ, Fozard JL and Hurley BF. J Gerontol A Biol Sci Med Sci 55: B152–B157, 2000) that improvements in muscle function with ST result from nonmuscle mass adaptations to a greater extent in women than men.
Management of Superior Canal Dehiscence Syndrome with Extensive Skull-Base Deficiency
Authors: Pletcher Steven D. , Oghalai John S. , Reeck Jay B. , Cheung Steven W.
Published: July 2005

Superior canal dehiscence syndrome is a recently described condition resulting in noise- or pressure-induced vertigo. We review the case of a 50-year-old woman who presented with debilitating pressure and noise-induced vertigo as well as a low-frequency conductive hearing loss. Imaging was consistent with superior semicircular canal dehiscence syndrome. An extradural middle fossa approach was used to approach the dehiscent superior canal. Intraoperatively, our patient was found to have extensive idiopathic skull base dehiscence of the temporal floor. Middle ear and mastoid mucosa was exposed with focal areas of dura prolapsed into the mastoid cavity. Because of these findings, temporalis fascia and bone pate were used to cover the dehiscent canal as well as a large area of the temporal floor. Additionally, a temporalis muscle flap was rotated between the dura and the dehiscent temporal floor to reconstruct the middle fossa skull base and prevent encephalocele.
The Functional Role of C-Reactive Protein in Aortic Wall Calcification
Authors: Warrier Bharat , Mallipeddi Rama , Karla Pradeep Kumar , Lee Chi H.
Published: July 2005

As an ongoing effort to elucidate the mechanisms involved in bioprosthetic heart valve (BHV) calcification, the role of C-reactive protein (CRP) in the tissue calcification process was investigated. The profile of calcium-associated proteins (CAP) on glutaraldehyde-preserved (0.6%) porcine aortic wall, which were subcutaneously implanted in rats for up to 8 weeks, showed a temporal appearance pattern. The total extracted amount of proteins from the control tissues implanted for 8 weeks was significantly greater than that from ethanol-treated tissues (1.78 ± 0.2 vs. 1.27 ± 0.18 µg/mg), indicating that the binding affinity of CAP for BHV pretreated with an anticalcification agent was significantly decreased (p < 0.05). The dye Stains-All method showed that the dark-blue colored bands, representing high calcium binding and phosphorylated proteins, were stained from the extract of the control BHV at the molecular weight varying from 4 to 250 kDa, but rarely seen in the extract of BHV pretreated with ethanol. One of those proteins was exclusively immunoreactive with CRP antibody, while there was no immunoreaction in less calcified tissues. When aortic wall was exposed to an excess amount of CRP in an in vitro simulating model, the calcification rate of aortic wall increased as the concentration of CRP increased. The results of this work clearly revealed that CRP has indirect vascular effects, leading to an increased rate of aortic wall calcification.
Plasma C-Reactive Protein and Lipoprotein Levels, and Progression of Coronary Artery Disease after Myocardial Infarction Treated with Thrombolysis
Authors: Tornvall Per , Hamsten Anders , Hansson Lars-Olof , O’Konor Marie-Louise , Ericsson Carl-Göran , Strandberg Lars-Erik , Boavida Antonio , Bergstrand Lott
Published: July 2005

Background: There is a paucity of studies using quantitative coronary angiography (QCA) to determine progression of coronary artery disease (CAD) after an acute coronary event. Furthermore, despite a great interest in effects of inflammation and ‘early’ lipid lowering therapy, no data have been published on the role of plasma C-reactive protein (CRP) and lipoprotein levels in CAD progression after myocardial infarction. Methods: Seventy-two patients with myocardial infarction treated with thrombolysis, but not with statins, were investigated with QCA during admission and after 6 months. Plasma CRP concentrations were measured by a high sensitive method 2 days after the acute event, and plasma high-sensitive CRP and lipoprotein levels were determined 3 months after myocardial infarction. Results: Overall, there was no significant progression of CAD, but when stenoses were grouped into those reducing the lumen diameter greater or less than 50%, progression was seen in stenoses originally <50%, whereas regression was seen in stenoses >50%. No consistent associations were seen between plasma CRP, lipoprotein lipid or lipoprotein(a) levels and CAD. Conclusions: Progression of stenoses <50% might be of clinical importance since these stenoses are more prone to rupture. Furthermore, the lack of associations between change in minimum lumen diameter and plasma CRP and lipoprotein concentrations suggests that positive effects on CAD progression of early treatment with anti-inflammatory or lipid-lowering drug therapy may not be expected in this subset of patients.
Does a Carbon Ion-Implanted Surface Reduce the Restenosis Rate of Coronary Stents?
Authors: Jung Jae-Hun , Min Pil-Ki , Kim Jong-Youn , Park Sungha , Choi Eui-Young , Ko Young-Guk , Choi Donghoon , Jang Yangsoo , Shim Won-Heum , Cho Seung-Yun
Published: July 2005

Background: Neointimal hyperplasia and resulting restenosis limit the long-term success of coronary stenting. Heavy metal ions induce an inflammatory and allergic reaction, and result in in-stent restenosis. However, a carbon ion-implanted surface might prevent heavy metal ions from diffusing into surrounding tissue. Methods: 140 lesions in 140 patients with coronary lesions underwent implantation of carbon-implanted surface stents (Arthosinert stent group, n = 70) or control stents (Arthos stent group, n = 70). The primary end point was the in-stent restenosis and the secondary end point was the value of hs-CRP at 48 h and 6 months after coronary stenting. Clinical and angiographic follow-ups were performed at 6 months. Results: The rate of in-stent restenosis was lower in the Arthosinert stent group (15.9%, 10/63) than in the Arthos stent group (20.9%, 13/62), but there were no significant differences between both groups (p = 0.56). The value of hs-CRP at 48 h was lower in the Arthosinert stent group (13.9 ± 13.4 mg/dl) than in the Arthos stent group (24.5 ± 26.0 mg/dl) with significant differences (p = 0.04). However, the differences between two groups were not statistically significant at 6 months (p = 0.76). Conclusions: As compared with a standard coronary stent, a carbon ion-implanted stent shows no considerable benefit for the prevention of in-stent restenosis within the range of this study. Despite all the limitations of this study, a positive effect of a carbon ion-implanted stent in reducing inflammatory reaction after coronary revascularization seems likely.
p-Value Simulation for Affected Sib Pair Multiple Testing
Authors: Wu Xiaoling , Naiman Daniel Q.
Published: July 2005

A standard approach to calculation of critical values for affected sib pair multiple testing is based on: (a) fully informative markers, (b) Haldane map function assumptions leading to a Markov chain model for inheritance vectors, (c) central limit approximation to averages of sampled inheritance vectors leading to an Ornstein-Uhlenbeck process approximation, and (d) simple approximations to the maximum of such a process. Under these assumptions, assuming equispaced or close to equispaced markers, if the sample size is large, an approximation is available that is easy to calculate and performs well. However, for small sample sizes, a large number of markers, and for small p-values, there is good reason to be cautious about the use of the Gaussian approximation. We develop an algorithm for calculation of multiple testing p-values based on the standard Markov chain model, avoiding the use of Gaussian (large sample) approximation. We illustrate the use of this algorithm by demonstrating some inadequacies of the Gaussian approximation.
The Posterior Probability of Linkage Allowing for Linkage Disequilibrium and a New Estimate of Disequilibrium between a Trait and a Marker
Authors: Yang Xinqun , Huang Jian , Logue Mark W. , Vieland Veronica J.
Published: July 2005

The posterior probability of linkage (PPL) statistic has been developed as a method for the rigorous accumulation of evidence for or against linkage allowing for both intra- and inter-sample heterogeneity. To date, the method has assumed linkage equilibrium between alleles at the trait locus and the marker locus. We now generalize the PPL to allow for linkage disequilibrium (LD), by incorporating variable phase probabilities into the underlying linkage likelihood. This enables us to recover the marginal posterior density of the recombination fraction, integrating out nuisance parameters of the trait model, including the locus heterogeneity (admixture) parameter, as well as a vector of LD parameters. The marginal posterior density can then be updated across data subsets or new data as they become available, while allowing parameters of the trait model to vary between data sets. The method applies immediately to general pedigree structures and to markers with multiple alleles. In the case of SNPs, the likelihood is parameterized in terms of the standard single LD parameter D′; and it therefore affords a mechanism for estimation of D′ between the marker and the trait, again, without fixing the parameters of the trait model and allowing for updating across data sets. It is even possible to allow for a different associated allele in different populations, while accumulating information regarding the strength of LD. While a computationally efficient implementation for multi-allelic markers is still in progress, we have implemented a version of this new LD-PPL for SNPs and evaluated its performance in nuclear families. Our simulations show that LD-PPLs tend to be larger than PPLs (stronger evidence in favor of linkage/LD) with increased LD level, under a variety of generating models; while in the absence of linkage and LD, LD-PPLs tend to be smaller than PPLs (stronger evidence against linkage). The estimate of D′ also behaves well even in relatively small, heterogeneous samples.
Natural History of Progressive Supranuclear Palsy: A Clinicopathologic Study from a Population of Brain Donors
Authors: Papapetropoulos Spiridon , Gonzalez Jocely , Mash Deborah C.
Published: July 2005

Progressive supranuclear palsy (PSP) is the second most common parkinsonian syndrome, characterized by a ‘diverse’ clinical phenotype. Although several different diagnostic guidelines have been proposed, the early and accurate diagnosis of PSP remains problematic and neuropathology is still considered the ‘gold standard’. In order to contribute to the better clinical characterization of PSP, we conducted a postmortem study in a cohort of 22 consecutive PSP brain donors and compared our results with those of previously published reports. Our results further demonstrate and expand the varied clinical picture of PSP. Furthermore, we report associations between older age at onset, early dementia, early falls and smoking with shorter PSP duration.
The Absence of Immunoreactivity for Tissue Inhibitor of Metalloproteinase-1 (TIMP-1), but Not for TIMP-2, Protein Is Associated with a Favorable Prognosis in Aggressive Breast Carcinoma
Authors: Kuvaja Paula , Talvensaari-Mattila Anne , Pääkkö Paavo , Turpeenniemi-Hujanen Taina
Published: July 2005

Objectives: High tumor grade and lymph node positivity are associated with poor prognosis in breast carcinoma. Prognostic markers are used to define which patient groups benefit from different treatment modalities, some of which are potentially very toxic. Matrix metalloproteinases (MMPs) degrade the extracellular matrix, and type IV collagenases MMP-2 and -9 have been linked to invasive behavior of several malignancies. Tissue inhibitors of metalloproteinases (TIMPs) -1 and -2 inhibit their activity and are therefore considered to have an inhibitory effect on tumor progression. The role of TIMPs in progression of breast carcinoma is, however, still poorly known. Here the effect of TIMP-1 and -2 on survival was examined in lymph node-positive breast carcinoma patients. Methods: TIMP-1 or -2 was evaluated with avidin-biotin immunohistochemical staining from paraffin-embedded sections of primary breast carcinoma of 132 cases. Results: Positive staining for TIMP-1 and -2 was observed in 81 and 84% of the tumors respectively. TIMP-1 correlated to the grade of the tumor (p = 0.047). Absence of TIMP-1 protein correlated with favorable disease-specific survival of the patients with high-grade tumors. After 10 years of follow-up as high as 88% of patients with a grade 2–3, but TIMP-1-negative tumor were alive, when only 61% of the TIMP-1-positive cases in this group survived by that time (p = 0.03). Conclusion: Our results suggest that lack of TIMP-1 protein expression is associated with a favorable prognosis in patients with node-positive high-grade breast carcinoma.
Autocrine Vascular Endothelial Growth Factor/Vascular Endothelial Growth Factor Receptor-2 Growth Pathway Represents a Cyclooxygenase-2-Independent Target for the Cyclooxygenase-2 Inhibitor NS-398 in Colon Cancer Cells
Authors: Kim Seok Jin , Seo Jae Hong , Lee Yoo Jung , Yoon Ji Hye , Choi Chul Won , Kim Byung Soo , Shin Sang Won , Kim Yeul Hong , Kim Jun Suk
Published: July 2005

Objectives: Coexpression of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR-2) has been reported in tumor cells, suggesting the presence of an autocrine VEGF/VEGFR-2 growth pathway in solid tumors. Thus, we hypothesize that the presence of this autocrine pathway in colon cancer cells may be a COX-2-independent target of COX-2 inhibitors and a mechanism behind the antitumor effects of these agents. Methods: COX-2-positive (Caco2, HT-29) and COX-2-negative colon cancer cells (DLD-1, Hct-15) were used. Expression of VEGFR-2 was evaluated by Western blot and reverse transcriptase-polymerase chain reaction and VEGF production was measured from culture supernatant by enzyme-linked immunosorbent assay. Growth inhibition and the expression of VEGF and VEGFR-2 were compared after treatment with the COX-2 inhibitor, NS-398 at doses ranging from 5 to 100 µM. Results: VEGF and VEGFR-2 were expressed in all four colon cancer cells and a blockade of VEGFR-2 with anti-VEGFR-2 antibody treatment induced growth inhibition of colon cancer cells, supporting the presence of autocrine VEGF/VEGFR-2 growth pathway. NS-398 suppressed the growth of colon cancer cells, independent of COX-2 expression. VEGFR-2 expression of tumor cells was reduced after NS-398 treatment at 100 µM, the concentration at which maximal growth inhibition was induced. The amount of VEGF in culture supernatant was increased by NS-398 at 100 µM, suggesting increased secretion of VEGF in compensation for reduced VEGFR-2 expression. Conclusion: The autocrine VEGF/VEGFR-2 growth pathway could be a COX-2-independent target of the COX-2 inhibitor, NS-398, in colon cancer cells.
The Role of 5-Fluorouracil (5-FU) Reintroduction with Irinotecan or Oxaliplatin in Truly 5-FU-Refractory Advanced Colorectal Cancer Patients
Authors: Scartozzi M. , Sobrero A. , Gasparini G. , Berardi R. , Catalano V. , Graziano F. , Barni S. , Zaniboni A. , Beretta G.D. , Labianca R. , Cascinu S.
Published: July 2005

Objectives: Although several evidences have demonstrated a synergistic activity of 5-fluorouracil with irinotecan and oxaliplatin, thus explaining the use of this drug combination in the first-line treatment of advanced colorectal cancer, the need for the reintroduction of 5-FU in the second-line setting is more questionable. Methods: We retrospectively evaluated the outcome of patients developing progressive disease while on an infusional 5-FU-based front-line chemotherapy and subsequently treated with one of the four following chemotherapy regimens: irinotecan, oxaliplatin and irinotecan or oxaliplatin both combined with the de Gramont schedule (LV5-FU2). Results: 225 patients (137 males and 88 females), were eligible for analysis. Second-line chemotherapy consisted of irinotecan in 79 patients (35%, group A), oxaliplatin in 47 patients (21%, group B), irinotecan with LV5-FU2 in 53 patients (24%, group C) and oxaliplatin with LV5-FU2 in the remaining 46 cases (20%, group D). The response rate to second-line chemotherapy was obtained in 6/79 patients (8%) in group A, in 4/47 patients (9%) in group B, in 11/53 patients (21%) in group C and in 10/46 patients (22%) in group D (p = 0.04). Conclusions: These data suggest that reintroduction of 5-FU could increase irinotecan and oxaliplatin activity in patients progressing during a 5-FU-based first-line chemotherapy.
Alterations in Connexin26 Expression during Colorectal Carcinogenesis
Authors: Kanczuga-Koda Luiza , Sulkowski Stanislaw , Koda Mariusz , Sulkowska Mariola
Published: July 2005

Background: Gap junctional intercellular communication (GJIC) is a mechanism for direct cell-to-cell signalling and is mediated by gap junctions, which consist of transmembrane proteins called connexins (Cxs). Human colorectal epithelial cells express Cx32 and Cx43. Methods: Tissue samples (152 from colorectal cancer and 75 from adenoma) were investigated by immunohistochemistry, using the antibody for Cx26. Moreover, Cx26 was assessed in normal epithelium of the colon and rectum, adjacent to colorectal cancer. Results: In normal epithelium and adenomas, intercellular, punctate staining for Cx26 was observed. In adenomas with severe dysplasia, focally decreased expression of Cx26 was observed. Among 152 colorectal cancers, 55.9% classified only as adenocarcinoma stained positive for Cx26, but mainly cytoplasmic staining was found. We observed a positive correlation between Cx26 expression and tumor G2 grade (p < 0.005). The expression of Cx26 did not correlate with age, sex of patients, tumor localization, lymph node status or tumor size. Conclusions: Our results show that during colorectal carcinogenesis, loss of normal intercellular Cx expression occurs. Furthermore, the cytoplasmic presence of Cx26 could indicate a different role of Cx26 in neoplastic cells than participation in GJIC.
Secretory Carcinoma of the Breast
Authors: Ozguroglu Mustafa , Tascılar Koray , Ilvan Sennur , Soybir Gursel , Celik Varol
Published: July 2005

We report an elderly case of an indolent breast tumor in a 66-year-old woman. The patient presented with a locally advanced mass in the right breast that was present for 13 years, accompanied by bleeding and ulceration since the last 5 years. She had a modified radical mastectomy with axillary dissection. She was found to have secretory carcinoma with a tumor size of 8 × 4 × 4 cm in diameter. Two out of the 22 removed lymph nodes were involved. The secretory material stained positive with lactalbumin, as well as showed positivity with PAS. The patient received six cycles of adjuvant chemotherapy followed by chest wall irradiation. She is disease free with a follow-up period of 24 months. Preoperative chemotherapy should be primarily replaced by curative surgery in such indolent cancers, despite locally advanced disease.
Neuroimaging and Cardiac Correlates of Cognitive Function among Patients with Cardiac Disease
Authors: Paul Robert H. , Gunstad John , Poppas Athena , Tate David F. , Foreman Dan , Brickman Adam M. , Jefferson Angela L. , Hoth Karin , Cohen Ronald A.
Published: July 2005

In the present study, we examined the relationships between whole brain volume (WBV), subcortical hyperintensities (SH), indices of cardiac disease and cognitive function in nondemented cardiac patients with evidence of mild cerebrovascular disease. A total of 27 individuals with evidence of cardiac disease underwent neuropsychological examination, neuroimaging, and cardiac assessment. Cognition was assessed with the Dementia Rating Scale-2 (DRS). WBV and SH were quantified using a semi-automated thresholding program based on MRI. Correlational analyses revealed that WBV predicted performance on the overall DRS score, the attention subscale and the initiation/perseveration scale. SH were significantly associated with performance on the attention subscale, and the initiation/perseveration subscale. Regression analyses revealed that SH accounted for most of the variance in the initiation/perseveration scale, whereas WBV accounted for most of the variance in the attention scale. The only cardiac structural or functional variable related to the neurological indices was aortic diameter, which was strongly related to both neuroimaging variables, as well as performances on the DRS attention and initiation/perseveration subscales. Our results highlight the importance of overall brain parenchyma in determining cognitive status among patients at risk for cognitive decline and suggest that select indices of structural cardiac morphology may be related to the early phases of cerebrovascular disease and cognitive status.
Dominant Optic Atrophy Caused by a Novel OPA1 Splice Site Mutation (IVS20+1G→A) Associated with Intron Retention
Authors: Hayashi Takaaki , Gekka Tamaki , Omoto Satoshi , Takeuchi Tomokazu , Kitahara Kenji
Published: July 2005

Dominant optic atrophy (DOA) is the most common form of inherited primary optic neuropathy. The purpose of the current study was to report a novel OPA1 splice site mutation and investigate the impact of the mutation on pre-mRNA splicing in a female proband and her father diagnosed with DOA. We evaluated visual acuity, retinal fundi and kinetic visual fields. Color vision phenotypes were determined using the Farnsworth Panel D-15 and the Farnsworth-Munsell 100-hue tests. All 28 coding exons of the OPA1 gene were analyzed with polymerase chain reaction (PCR) amplification and direct sequencing. Total RNA extraction from white blood cells followed by reverse transcription-PCR (RT-PCR) was performed. We identified a novel heterozygous G to A mutation at position +1 of intron 20 (g.IVS20+1G→A) in both patients. RT-PCR analysis revealed that the first 25 bp from intron 20 plus exon 20 were spliced onto exon 21. No difference in expression of mutant and wild-type transcripts was found within the linear range of amplification. Clinically, both patients exhibited reduced visual acuities, pallor of optic discs, decreased sensitivities of central visual fields and blue-yellow color vision defects. Previously, only one mechanism (skipping of exon) of pre-mRNA splicing defects has been reported among OPA1 splice site mutations. Our study demonstrates that the mechanism of intron retention is a novel type of pre-mRNA splicing defects. The mutant transcript with a premature termination codon is likely to encode a truncated protein, due to a translational frameshift (V672fsX675), that lacks 289 amino acids of the C-terminal end. Therefore, it is suggested that haploinsufficiency underlies DOA in the patients. However, we could not exclude the possibility that the truncated protein has a dominant negative activity because the mutant transcript is insusceptible to nonsense-mediated mRNA decay.
Postnatal Thyroid Hormone Supplementation Rescues Developmental Abnormalities Induced by Congenital-Neonatal Hypothyroidism in the Rat Retina
Authors: Pinazo-Durán M. Dolores , Iborra Francisco J. , Pons Sheila , Sevilla-Romero Enrique , Gallego-Pinazo Roberto , Muñoz Alberto
Published: July 2005

Thyroid hormones (TH) play a key role in central nervous system development. We have studied the influence of congenital and neonatal hypothyroidism on retinal development and the effects of postnatal TH supplementation. An experimental model was set up using Wistar rats by inducing chemical thyroidectomy during gestation and suckling. Eyes from control (CG) and TH-depleted (THDG) groups of animals were obtained at postnatal days 10 and 25. In the THDG, there was a significant reduction in the retinal thickness and layering, retinal volume, cell number and nuclear volumes in all layers. A third group of rats, made hypothyroid during the gestational and neonatal period and then supplemented with TH (THSG), showed a recovery of both the retinal thickness [at P25: 188.5 ± 9.2 µm (THSG) vs. 175.8 ± 16.1 µm (THDG), p < 0.001, and 210.8 ± 8.9 (CG)] and total retinal cell number [at P25: 6.9 × 106 (THSG) vs. 3.7 × 106 (THDG) cells, p < 0.001, and 5.3 × 106 cells (CG)]. Light and electron microscopy studies confirmed that TH deprivation altered the organization of the retina, which was mostly normalized by hormone administration. Our data show that TH regulates intrinsic mechanisms for controlling retinal cytoarchitecture and layering, and that alterations in retinal maturation induced by congenital-neonatal TH deficiency can be at least partially rescued by early hormonal treatment in vivo.
A New Procedure Allowing the Complete Removal and Prevention of Hemodialysis Biofilms
Authors: Marion Karine , Pasmore Mark , Freney Jean , Delawari Ehsan , Renaud François , Costerton John William , Traeger Jules
Published: July 2005

Most currently used disinfectants for dialysis machines have a good bactericidal efficacy on biofilms but leave dead cells on the surface. This contributes to the regrowth of biofilm and the release of pyrogens. A new anti-biofilm procedure consisting of sequential treatment combining enzymes and detergents is able to detach adherent cells. The efficacy of this procedure was assessed both in vitro and in reality. For in vitro studies, a biofilm model was set up. Studies were also performed in reality in a clinically used dialysis machine. Biofilm removal was first monitored by image analysis. Then, the biomass was detached by scraping and quantified by plate counts and endotoxin level measurement. Treated samples were compared to untreated control samples. The procedure led to the complete detachment of the biomass, both in vitro and in the reality situation. The aim of thisprocedure is to replace or complete the usual disinfection methods for medical devices.
Exposure to Retinyl Esters, Retinol, and Retinoic Acids in Non-Pregnant Women following Increasing Single and Repeated Oral Doses of Vitamin A
Authors: Hartmann Stefan , Brørs Odd , Bock Jürgen , Blomhoff Rune , Bausch Jochen , Wiegand Ulf-W. , Hartmann Dieter , Hornig Dietrich H.
Published: July 2005

Background: High intakes of vitamin A cause congenital malformations in experimental animals with elevated generation of retinoic acids (RA). Results in humans are conflicting. Objective: To evaluate plasma concentration-time curves of retinyl esters, retinol and their metabolites at increasing doses of vitamin A. Methods: An open-label dose-response study. Non-pregnant females (3 groups with n = 12; 18–40 years) received once daily oral doses of vitamin A palmitate up to 30,000 IU/day over 21 days. The area under the plasma concentration-time curve (AUC24h) served as indicator for exposure. Results: AUC24h of retinyl esters increased linearly with dose. Retinol concentrations were unaffected. All-trans RA exhibited a diurnal-like concentration-time profile (Cmax at 3 h; Cmin at 8 h), concentrations decreasing below pre-dose levels at 5 h and regaining pre-dose levels at 16 h. The maximum temporary increase in exposure was 33% (single dose) and 19% (repeated doses) above baseline, but AUC24h remained unaltered. AUC24h increased linearly with dose for 13-cis RA and 13-cis-4-oxo RA. Repeated doses caused a 25% increase in exposure with the highest vitamin A intake. Accumulation of 13-cis- 4-oxo RA at 30,000 IU/day doubled compared to the 4,000 IU/day intake. Conclusion: Repeated oral doses of up to 30,000 IU of vitamin A in addition to dietary vitamin A were without safety concern. Safe doses are probably higher, since plasma concentrations and exposure to RA remained at levels earlier shown to be without increased risk of teratogenicity in pregnant women.
Influence of Diet on Exposure to Acrylamide – Reflections on the Validity of a Questionnaire
Authors: Kütting Birgitta , Schettgen Thomas , Beckmann Matthias W. , Angerer Jürgen , Drexler Hans
Published: July 2005

Aim: This pilot study attempts to assess how far the standardized questionnaires are a valid tool to detect the food-related burden of acrylamide. Acrylamide is a toxic substance classified by the International Agency of Research on Cancer, as well as the Deutsche Forschungsgemeinschaft, as a probable human carcinogen. Methods: A venous blood sample was taken in order to determine the smoking-specific acrylnitrile adduct N-cyanoethylvaline and the acrylamide adduct N-2-carbamoylethylvaline in a female study population expecting delivery soon. A standardized questionnaire was used to determine the consumption of acrylamide-contaminated food. The results of our questionnaire were transferred to a linear evaluation system. Finally, anamnestic data of the questionnaire were correlated to objective parameters such as blood levels of hemoglobin adducts of acrylamide and acrylonitrile. Results: A positive correlation between the acrylamide intake and the levels of hemoglobin adducts in our study population was not proven. Conclusions: Evaluation of food-related exposure to acrylamide is difficult due to several reasons. Firstly, the validity of anamnestic data strongly depends on the patient’s ability to remember precisely all consumed food (quality as well as quantity) over a 3-month period. In addition, the contamination of acrylamide in food varies from one product to another; even the contamination of the same product is variable. Therefore, the missing correlation between the questionnaire and hemoglobin adduct rates is rather due to restricted validity of anamnestic data.