bluuebunny/crossref_metadata_2025 huggingface dataset:
A neural set point for the long-term control of arterial pressure: beyond the arterial baroreceptor reflex
Authors: Osborn John W. , Jacob Frédéric , Guzman Pilar
Published: March 2005

Arterial baroreceptor reflex control of renal sympathetic nerve activity (RSNA) has been proposed to play a role in long-term control of arterial pressure. The hypothesis that the “set point” of the acute RSNA baroreflex curve determines the long-term level of arterial pressure is presented and challenged. Contrary to the hypothesis, studies on the long-term effects of sinoaortic denervation (SAD) on arterial pressure and RSNA, as well as more recent studies of chronic baroreceptor “unloading” on arterial pressure, suggest that the basal levels of sympathetic nerve activity and arterial pressure are regulated independent of arterial baroreceptor input to the brainstem. Studies of the effect of SAD on the long-term salt sensitivity of arterial pressure are consistent with a short-term role, rather than a long-term role for the arterial baroreceptor reflex in regulation of arterial pressure during changes in dietary salt intake. Renal denervation studies suggest that renal nerves contribute to maintenance of the basal levels of arterial pressure. However, evidence that baroreflex control of the kidney plays a role in the maintenance of arterial pressure during changes in dietary salt intake is lacking. It is proposed that a “baroreflex-independent” sympathetic control system must exist for the long-term regulation of sympathetic nerve activity and arterial pressure. The concept of a central nervous system “set point” for long-term control of mean arterial pressure (CNS-MAP set point), and its involvement in the pathogenesis of hypertension, is discussed.
Recent insights into the interactions between the baroreflex and the kidneys in hypertension
Authors: Lohmeier Thomas E. , Hildebrandt Drew A. , Warren Susan , May Paul J. , Cunningham J. Thomas
Published: March 2005

Recent findings in chronically instrumented animals challenge the classic concept that baroreflexes do not play a role in the chronic regulation of arterial pressure. As alterations in renal excretory function are of paramount importance in the chronic regulation of arterial pressure, several of these recent studies have focused on the long-term interactions between the baroreflex and the kidneys during chronic perturbations in arterial pressure and body fluid volumes. An emerging body of evidence indicates that the baroreflex is chronically activated in several experimental models of hypertension, but in most cases, the duration of these studies has not exceeded 2 wk. Although these studies suggest that the baroreflex may play a compensatory role in attenuating the severity of the hypertension, possibly even in primary hypertension with uncertain causes of sympathetic activation, there has been only limited assessment of the quantitative importance of this interaction in the regulation of arterial pressure. In experimental models of secondary hypertension, baroreflex suppression of renal sympathetic nerve activity is sustained and chronically promotes sodium excretion. This raises the possibility that the renal nerves may be the critical efferent link for baroreceptor-induced suppression of central sympathetic output through which long-term compensatory reductions in arterial pressure are produced. This contention is supported by strong theoretical evidence but must be corroborated by experimental studies. Finally, although it is now clear that pressure-induced increases in baroreflex activity persist for longer periods of time than previously suggested, studies using new tools and novel approaches and extending beyond 2 wk of hypertension are needed to elucidate the true role of the baroreflex in the pathogenesis of clinical hypertension.
Flash photolysis of caged nitric oxide inhibits proximal tubular fluid reabsorption in free-flow nephron
Authors: Yip Kay-Pong
Published: March 2005

A nonobstructing optical method was developed to measure proximal tubular fluid reabsorption in rat nephron at 0.25 Hz. The effects of uncaging luminal nitric oxide (NO) on proximal tubular reabsorption were investigated with this method. Proximal fluid reabsorption rate was calculated as the difference of tubular flow measured simultaneously at two locations (0.8–1.8 mm apart) along a convoluted proximal tubule. Tubular flow was estimated on the basis of the propagating velocity of fluorescent dextran pulses in the lumen. Changes in local tubular flow induced by intratubular perfusion were detected simultaneously along the proximal tubule, indicating that local tubular flow can be monitored in multiple sites along a tubule. The estimated tubular reabsorption rate was 5.52 ± 0.38 nl·min−1·mm−1 ( n = 20). Flash photolysis of luminal caged NO (potassium nitrosylpentachlororuthenate) was induced with a 30-Hz UV nitrogen-pulsed laser. Release of NO from caged NO into the proximal tubule was confirmed by monitoring intracellular NO concentration using a cell-permeant NO-sensitive fluorescent dye (DAF-FM). Emission of DAF-FM was proportional to the number of laser pulses used for uncaging. Photolysis of luminal caged NO induced a dose-dependent inhibition of proximal tubular reabsorption without activating tubuloglomerular feedback, whereas uncaging of intracellular cGMP in the proximal tubule decreased tubular flow. Coupling of this novel method to measure reabsorption with photolysis of caged signaling molecules provides a new paradigm to study tubular reabsorption with ambient tubular flow.
Magnesium Sulfate in Aneurysmal Subarachnoid Hemorrhage
Authors: van den Bergh Walter M.
Published: March 2005

Background and Purpose—

Magnesium reverses cerebral vasospasm and reduces infarct volume after experimental subarachnoid hemorrhage (SAH) in rats. We aimed to assess whether magnesium reduces the frequency of delayed cerebral ischemia (DCI) in patients with aneurysmal SAH.

Methods—

Patients were randomized within 4 days after SAH. Magnesium sulfate therapy consisted of a continuous intravenous dose of 64 mmol/L per day, to be started within 4 days after SAH and continued until 14 days after occlusion of the aneurysm. The primary outcome DCI (defined as the occurrence of a new hypodense lesion on computed tomography compatible with clinical features of DCI) was analyzed according to the “on-treatment” principle. For the secondary outcome measures “poor outcome” (Rankin >3) and “excellent outcome” (Rankin 0), we used the “intention-to-treat” principle.

Results—

A total of 283 patients were randomized. Magnesium treatment reduced the risk of DCI by 34% (hazard ratio, 0.66; 95% CI, 0.38 to 1.14). After 3 months, the risk reduction for poor outcome was 23% (risk ratio, 0.77; 95% CI, 0.54 to 1.09). At that time, 18 patients in the treatment group and 6 in the placebo group had an excellent outcome (risk ratio, 3.4; 95% CI, 1.3 to 8.9).

Conclusions—

This study suggests that magnesium reduces DCI and subsequent poor outcome, but the results are not yet definitive. A next step should be a phase III trial to confirm the beneficial effect of magnesium therapy, with poor outcome as primary outcome.
A Multilevel Approach to Investigating Cross-National Differences in Negotiation Processes
Authors:   Huang, Van de Vliert Evert
Published: March 2005

The impact of the psychological states of the negotiators, the social conditions of negotiations, and the behavior of negotiators on the outcomes of negotiations differs from country to country. Various suboptimal, individual-level, and country-level solutions have been suggested to predict and explain such cross-national variations. Drawing inspiration from a series of cross-cultural studies on job satisfaction and motives for volunteer work that successfully employed multilevel modeling, we propose a multilevel research approach to more accurately examine the generalizability of negotiation models across countries.
Introduction
Authors:   La Pergola
Published: March 2005

No Abstract
Cognitive-Behavioral Treatment Combined With Asthma Education for Adults With Asthma and Coexisting Panic Disorder
Authors: Ross Carolyn J. M. , Davis Terry M. A. , Macdonald G. Fred
Published: March 2005

This study tested the efficacy of a nurse-administered 8-week group treatment program for adults with asthma suffering from coexisting panic disorder. The program consisted of cognitive behavioral treatment (CBT) for panic disorder combined with asthma education (AE). Forty-eight women with a confirmed diagnosis of asthma and panic disorder were randomly allocated to a treatment condition (n=25) and a wait-list control condition (n=23). Twenty-five participants—15 in the treatment group and 10 in the wait-list control group— completed treatment. Repeated measures ANOVA procedures were used to compare the groups on panic and asthma outcomes at posttreatment and 6-month follow-up. The results demonstrate that the CBT-AE program is capable of producing substantial and durable antipanic and antianxiety treatment effects and led to substantial but nonsustained improvement in morning peak-flow expiratory rate and asthma-related quality of life. Implications of these findings for this clinical population are addressed.
Beyond Federal Urban Policy
Authors: Barnes William R.
Published: March 2005

Under Democratic and Republican leaders alike, urban policy has receded into a Washington backwater, and it is unlikely to reemerge as a priority any time soon. This essay provides a brief narrative of the rise and fall of urban policy, with a focus on the climax of urban policy making in the late 1970s. The essay also offers some thoughts on the frameworks—the architecture—the status and alignment of which affects the prospects for federal government involvement in local problem solving and building quality communities.
Structure analysis of montmorillonite crystallites by convergent-beam electron diffraction
Authors: Beermann T. , Brockamp O.
Published: March 2005

The small particle size and the random stacking of layers has previously hindered systematic structure investigations of montmorillonite. By applying the convergent-beam electron diffraction mode (CBED) of a transmission electron microscope (TEM) with a beam spot of ~800 Å we were able to examine undisturbed areas of montmorillonite crystallites.

Because montmorillonite crystallites are mostly thin particles, kinematic theory can be applied and the CBED patterns can be interpreted directly, provided that the particle thickness remains below the critical value of 350 Å. An average thickness of ~90 Å was calculated here for montmorillonite of bulk samples from X-ray diffraction analysis and lattice-fringe images. However, satisfactory diffraction intensity patterns for quantitative evaluation were obtained only from crystallites with a thickness above the average, which yielded a sufficient scattering volume. These patterns could be described in terms of the kinematic theory and therefore these crystallites were <350 Å thick. Yet, crystallites of adequate thickness were extremely rare in the three samples investigated (Clay Spur, Rock River and Upton, all in Wyoming, USA).

The diffraction intensities from theabplane of single montmorillonite crystallites of the various origins fit the three structural models for atrans-vacancy distribution, acis-vacancy distribution or a random-cation distribution within the octahedral sheets. The configuration of the diffraction patterns also shows a 1Msymmetry of the layer. Due to the limited data set of CBED patterns, a refinement of the structure could not be achieved. However, energy dispersive X-ray spectroscopy data and computation of the cation–anion distances and valences using the ‘distance valence least square’ program permitted a refinement of the models.
Alteration of smectites induced by hydrolytic exchange
Authors: Ramirez S. , Righi D. , Petit S.
Published: March 2005

Hydrolytic exchange was performed experimentally on four smectitic clays to evaluate the extent of clay alteration induced by this process and the associated ‘auto-transformation’ of H+ clays. Clay samples were Na-saturated and submitted to 10, 50 and 100 wetting-drying (WD) cycles and characterized after treatment using X-ray diffraction (XRD), infrared spectroscopy (FTIR) and cation exchange capacity analysis. Evidence for hydrolytic exchange was given by increasing amounts of exchangeable Mg2+ and precipitation of Na soluble salts for samples subjected to 100 WD cycles. Results indicated a decrease in the interlayer charge after 10 WD cycles but no further decrease was observed after 50 and 100 WD cycles. For one sample, XRD data indicated a decrease in the proportion of the smectite phase and a relative increase in the concentration of illite-smectite mixed layers also present in the sample. The results suggested that the reaction induces first a decrease in the layer charge and then a partial dissolution of some smectite layers.
Clayey materials from the Sierra de la Demanda Range (Spain): their potential as raw materials for the building ceramics industry
Authors: Artigas R. , Rodas M. , Sánchez C. J. , Mas R. , Dondi M. , Arribas J.
Published: March 2005

This work describes the possible use of thick Early Cretaceous clay deposits, which occur in the southern sector of the Sierra de la Demanda range, as raw materials in the manufacture of ceramic articles. The global mineralogical composition is characterized by high proportions of phyllosilicates and quartz with variable quantities of feldspars, carbonates and hematite. The clay mineralogy differentiates two types of raw materials: illitic clay and kaolinitic-illitic clay. A granulometric distribution in the 2–60 µm fraction, good behaviour during the drying stage and acceptable results in firing tests confirmed that most samples can be utilized as raw material in the building ceramics industry. The range of suitable firing temperatures for these materials is 950–1000°C, a temperature which needs to be raised for samples with a high percentage of kaolinite and quartz. Moreover, other materials with abundant calcite (20–30%) are suitable for use as modifiers of some properties or colour.
Clay minerals in hydrothermally altered basalts from Middle Atlas, Morocco
Authors: Dekayir A. , Amouric M. , Olives J.
Published: March 2005

Clay minerals occur as replacements of olivine, pyroxenes, plagioclase and interstitial materials, and as vesicle fillings, in altered basalts from the Middle Atlas (Morocco). Phyllosilicates are the main components of this alteration process. They have been characterized here by optical microscopy, X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy as saponite, talc, corrensite and chlorite. The homogeneity of the chemical compositions of these phyllosilicates, in different alteration environments, probably means that they are controlled by the composition of the hydrothermal fluid. Talc-saponite-corrensite (with dominant saponite) is the clay mineral association most frequently observed (corrensite being more abundant in the vesicular levels of the basalts). Such an association, with no evidence of albite and zeolite, suggests that these basalts have suffered minimal alteration at relatively low temperatures. Another association, chlorite-corrensite, was detected in a deeper (vesicular) sample, probably resulting from a slightly higher temperature. Lastly, only discrete phyllosilicates (i.e. no random mixed-layer minerals) were observed. This suggests that near-equilibrium conditions prevailed during this alteration stage and that a dissolution-crystallization process was the main mechanism of transformation.
Retrograde diagenesis, a widespread process on a regional scale
Authors: Nieto F. , Pilar Mata M. , Bauluz B. , Giorgetti G. , Árkai P. , Peacor D. R.
Published: March 2005

Pelitic and basic rocks occurring within prograde sequences in Portugal, Spain and Hungary have been studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The minerals formed in typical prograde reactions define the general sequences, but smectite, chlorite-smectite (corrensite) and/or berthierine were found to have replaced chlorite, whereas kaolinite and mixed-layer illite-smectite replaced illite-muscovite. Alteration occurred under conditions normally associated with diagenesis, subsequent to regional metamorphism, and we therefore refer to such processes with the term “retrograde diagenesis”. In the cases studied and in other cited examples, reactions occurred on a regional basis via pervasive fluids under open-system conditions inferred to be related to tectonic stress. The observed alterations could generally not be inferred from XRD data, although the presence of pure smectite in sediments other than bentonite is suggestive of retrograde relations, especially where other minerals are consistent with a higher grade of diagenesis. Retrograde diagenesis is readily observed through imaging of textures by TEM, however. Textural features show that retrograde reactions are more common than generally assumed, and that care should be used in interpreting geological events where appropriate textural relations are not seen.
Mineralogy, geochemistry and genesis of bentonites of the Ordu area, NE Turkey
Authors: Abdioğlu E. , Arslan M.
Published: March 2005

A number of bentonitic clay deposits from the Ordu area (NE Turkey) have been investigated by optical and electron microscopy, X-ray diffraction and chemical analysis. The clays are the alteration products of Late Cretaceous trachytic and trachyandesitic pyroclastic rocks. They contain volcanogenic sanidine, plagioclase, biotite and pumice, along with the diagenetic minerals opal-CT, cristobalite and rare calcite and zeolite (clinoptilolite). Ca-smectite (montmorillonite) is the dominant clay mineral. The rare earth element patterns of all the bentonitic clays are generally similar, although there are variations in the Eu anomaly indicating formation from different types of pyroclastic rocks. Oxygen and hydrogen stable isotope values suggest that the smectite was formed at 20–40°C in pore water of mixed meteoric and marine origin during argillization. These features, together with mass-balance calculations, indicate the enhanced MgO and Sr content of the smectite resulted from formation at shallow burial depths within a dominantly marine environment.
Basalt petrology, zircon ages and sapphire genesis from Dak Nong, southern Vietnam
Authors: Garnier V. , Ohnenstetter D. , Giuliani G. , Fallick A. E. , Phan Trong T. , Hoàng Quang V. , Pham Van L. , Schwarz D.
Published: March 2005

Basalts associated with sapphire deposits are widespread in Europe, Africa, Asia and Australia. In Vietnam, blue, green and yellow sapphires are recovered from eluvial and alluvial placers hosted in basaltic fields of the Dak Lak Province. Two distinct basalt suites are recognized in this field: a tholeiitic suite without any xenocrysts and an alkaline suite with mantle and lower crustal xenocrysts. The sapphires are enriched in Fe (0.43 to 1.26 wt.%), with moderate contents of Cr (33–1582 ppm), Ti (35–1080 ppm), Ga (149–308 ppm) and V (28–438 ppm) and they are poor in Zn and Mg. Their O-isotope compositions range from 6.0 to 6.9% and are not in equilibrium with the alkali basalts which have δ18O values between 5.0 and 5.7%. The U-Pb dating of zircons recovered from the basaltic placers provides evidence of two eruptional events: one at ~6.5 Ma followed by another one at ~1 Ma. The petrography of the basalts and the oxygen isotopic composition of the sapphires suggest that the sapphires are xenocrysts and that they crystallized in a deep magma chamber, at the lower continental lithosphere and the upper mantle boundary, in evolved melts issued from the fractionation of alkali basaltic magmas contaminated with lower crustal fluids.
Re-investigation of the crystal structure of whewellite [Ca(C2O4)·H2O] and the dehydration mechanism of caoxite [Ca(C2O4)·3H2O]
Authors: Echigo T. , Kimata M. , Kyono A. , Shimizu M. , Hatta T.
Published: March 2005

The crystal structure of whewellite [Ca(C2O4)·H2O] and the dehydration mechanism of caoxite [Ca(C2O4)·3H2O] have been studied by means of differential thermal analysis, X-ray diffraction (powder and single-crystal) analysis and infrared analysis. The first and second analyses confirmed the direct transformation of caoxite into whewellite without an intermediate weddellite [Ca(C2O4)·2H2O] stage. Infrared spectra obtained from caoxite, weddellite and whewellite emphasize the similarity of the O–H-stretching band and O–C–O-stretching band in whewellite and caoxite and the unique bands of weddellite. The structure refinement at low temperature (123 K) reveals that all the hydrogen atoms of whewellite form hydrogen bonds and the two water molecules prop up the crystal structure by the hydrogen bonds that cause a strong anisotropy of the displacement parameter.

Comparing the structural features of whewellite with those of weddellite and caoxite suggests that caoxite and whewellite have a sheet structure consisting of Ca2+ ions and oxalate ions although weddellite does not. It is additionally confirmed that the sheets of caoxite are corrugated by hydrogen bonds but whewellite has flat sheets. The corrugated sheets of caoxite would be flattened by dehydration so the direct transformation of caoxite into whewellite would not occur via weddellite. Essential for this transformation is the dehydration of interlayered water molecules in caoxite leading to the building of the crystal structure of whewellite on its intralayered water molecules. The difference in conformation of water molecules between those two crystal structures may explain the more common occurrence of whewellite than of caoxite in nature.
A novel missense mutation in ABCA1 results in altered protein trafficking and reduced phosphatidylserine translocation in a patient with Scott syndrome
Authors: Albrecht Christiane , McVey John H. , Elliott James I. , Sardini Alessandro , Kasza Ildiko , Mumford Andrew D. , Naoumova Rossi P. , Tuddenham Edward G. D. , Szabo Katalin , Higgins Christopher F.
Published: March 2005

Scott syndrome (SS) is a bleeding disorder characterized by a failure to expose phosphatidylserine (PS) to the outer leaflet of the platelet plasma membrane. Because the adenosine triphosphate (ATP)–binding cassette transporter A1 (ABCA1) is implicated in the exofacial translocation of PS, we assessed its role in the pathophysiology of a patient with SS. Substantially reduced levels of ABCA1 mRNA were found in the patient's leukocytes, compared with controls. The SS patient was heterozygous for a novel missense mutation c.6064G>A (ABCA1 R1925Q), absent from unaffected family members and controls. Both mutant and wild-type alleles were reduced in mRNA expression, and no causative mutation for this phenomenon was identified in the ABCA1 gene or its proximal promoter, suggesting a putative second mutation in a trans-acting regulatory gene may also be involved in the disorder in this patient. In vitro expression studies showed impaired trafficking of ABCA1 R1925Q to the plasma membrane. Overexpression of wild-type ABCA1 in SS lymphocytes complemented the Ca2+-dependent PS exposure at the cell surface. These data identify a mutation in ABCA1 that contributes to the defective PS translocation phenotype in our patient with SS.
Hematologic differences between African-Americans and whites: the roles of iron deficiency and α-thalassemia on hemoglobin levels and mean corpuscular volume
Authors: Beutler Ernest , West Carol
Published: March 2005

The average results of some laboratory measurements, including the hemoglobin, mean corpuscular volume (MCV), serum transferrin saturation (TS), serum ferritin, and white blood cell count of African-Americans differ from those of whites. Anonymized samples and laboratory data from 1491 African-American and 31 005 white subjects, approximately equally divided between men and women, were analyzed. The hematocrit, hemoglobin, MCV, TS, and white blood cell counts of African-Americans were lower than those of whites; serum ferritin levels were higher. When iron-deficient patients were eliminated from consideration the differences in hematocrit, hemoglobin, and MCV among women were slightly less. The -3.7-kilobase α-thalassemia deletion accounted for about one third of the difference in the hemoglobin levels of African-Americans and whites and neither sickle trait nor elevated creatinine levels had an effect. Among all subjects, 19.8% of African-American women would have been classified as “anemic” compared with 5.3% of whites. Among men, the figures were 17.7% and 7.6%. Without iron-deficient or thalassemic subjects, the difference had narrowed to 6.1% and 2.77% and to 4.29% and 3.6%, respectively. Physicians need to take into account that the same reference standards for hemoglobin, hematocrit, MCV, and TS and the white blood cell count do not apply to all ethnic groups. (Blood. 2005;106:740-745)
Osteo-Promoter Database (OPD) – Promoter analysis in skeletal cells
Authors: Grienberg Inbal , Benayahu Dafna
Published: March 2005

Background

Increasing our knowledge about the complex expression of genes in skeletal tissue will provide a better understanding of the physiology of skeletal cells. The study summarizes transcriptional regulation factors interacting and cooperating at promoter regions that regulate gene expression. Specifically, we analyzed A/T rich elements along the promoter sequences.

Description

The Osteo-Promoter Database (OPD) is a collection of genes and promoters expressed in skeletal cells. We have compiled a new viewer, OPD, as unique database developed and created as an accessible tool for skeletal promoter sequences. OPD can navigate to identify genes specific to skeletal cDNA databases and promoter analysis sites. OPD offers exclusive access to facilitate a dynamic extraction of promoters' gene-specific analyses in skeletal tissue. The data on promoters included in OPD contains cloned promoters or predicted promoters that were analyzed by bioinformatics tools. OPD offers MAR-analysis, which allocates A/T rich elements along these promoter sequences.

Conclusion

The analysis leads to a better insight of proteins that bind to DNA, regulate DNA, and function in chromatin remodeling. The OPD is a distinctive tool for understanding the complex function of chromatin remodeling and transcriptional regulation of specific gene expression in skeletal tissue.
The relation between plasma tyrosine concentration and fatigue in primary biliary cirrhosis and primary sclerosing cholangitis
Authors: ter Borg Pieter CJ , Fekkes Durk , Vrolijk Jan Maarten , van Buuren Henk R
Published: March 2005

Background

In primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) fatigue is a major clinical problem. Abnormal amino acid (AA) patterns have been implicated in the development of fatigue in several non-hepatological conditions but for PBC and PSC no data are available. This study aimed to identify abnormalities in AA patterns and to define their relation with fatigue.

Methods

Plasma concentrations of tyrosine, tryptophan, phenylalanine, valine, leucine and isoleucine were determined in plasma of patients with PBC (n = 45), PSC (n = 27), chronic hepatitis C (n = 22) and healthy controls (n = 73). Fatigue and quality of life were quantified using the Fisk fatigue severity scale, a visual analogue scale and the SF-36.

Results

Valine, isoleucine, leucine were significantly decreased in PBC and PSC. Tyrosine and phenylalanine were increased (p < 0.0002) and tryptophan decreased (p < 0.0001) in PBC. In PBC, but not in PSC, a significant inverse relation between tyrosine concentrations and fatigue and quality of life was found. Patients without fatigue and with good quality of life had increased tyrosine concentrations compared to fatigued patients. Multivariate analysis indicated that this relation was independent from disease activity or severity or presence of cirrhosis.

Conclusion

In patients with PBC and PSC, marked abnormalities in plasma AA patterns occur. Normal tyrosine concentrations, compared to increased concentrations, may be associated with fatigue and diminished quality of life.
Effects of aging and type 2 diabetes on resting and post occlusive hyperemia of the forearm; the impact of rosiglitazone
Authors: Petrofsky Jerrold , Lee Scott , Cuneo Maria
Published: March 2005

Background

Both Diabetes and ageing are associated with reduced vascular endothelial function. The exact relationship between the 2 and any improvements from the insulin sensitizer rosiglitazone have not been explored.

Methods

Thirty controls and sixteen subjects with type 2 diabetes participated in a series of experiments to examine the interrelationships between age, diabetes and endothelial cell function. In subjects with diabetes, the insulin sensitizer rosiglitazone (RSG), a drug also known to improve vascular function, was administered for 3 months to see how it altered these relationships. Resting forearm flows (RF) and blood flows after 4 min of vascular occlusion (PF) were measured as an index of endothelial cell function.

Results

RF, measured by venous occlusion plethysmography, was negatively correlated to both age and diabetes. Administration of RSG for 3 months was associated with an increase in the blood flow response to venous occlusion so that it was not significantly different than that of age matched controls. Total PF in control subjects, compared to subjects with diabetes, averaged 56.58 +/- 12.57 and 13.6 +/- 8.01 cc/100 cc tissue per min respectively, and were significantly different (p < 0.01). After 3 months on RSG, differences between PF in the two groups were no longer evident.

Conclusion

These studies suggest a different mechanism causing a reduction in vascular reactivity with aging and diabetes.
Differential expression of copper-associated and oxidative stress related proteins in a new variant of copper toxicosis in Doberman pinschers
Authors: Spee Bart , Mandigers Paul JJ , Arends Brigitte , Bode Peter , van den Ingh Ted SGAM , Hoffmann Gaby , Rothuizen Jan , Penning Louis C
Published: March 2005

Background

The role of copper accumulation in the onset of hepatitis is still unclear. Therefore, we investigated a spontaneous disease model of primary copper-toxicosis in Doberman pinschers so to gain insights into the pathophysiology of copper toxicosis, namely on genes involved in copper metabolism and reactive oxygen species (ROS) defences.

Results

We used quantitative real-time PCR to determine differentially expressed genes within a target panel, investigating different groups ranging from copper-associated subclinical hepatitis (CASH) to a clinical chronic hepatitis with high hepatic copper concentrations (Doberman hepatitis, DH). Furthermore, a non-copper associated subclinical hepatitis group (N-CASH) with normal hepatic copper concentrations was added as a control. Most mRNA levels of proteins involved in copper binding, transport, and excretion were around control values in the N-CASH and CASH group. In contrast, many of these (including ATP7A, ATP7B, ceruloplasmin, and metallothionein) were significantly reduced in the DH group. Measurements on defences against oxidative stress showed a decrease in gene-expression of superoxide dismutase 1 and catalase in both groups with high copper. Moreover, the anti-oxidative glutathione molecule was clearly reduced in the DH group.

Conclusion

In the DH group the expression of gene products involved in copper efflux was significantly reduced, which might explain the high hepatic copper levels in this disease. ROS defences were most likely impaired in the CASH and DH group. Overall, this study describes a new variant of primary copper toxicosis and could provide a molecular basis for equating future treatments in dog and in man.
Coronary flow reserve in stress-echo lab. From pathophysiologic toy to diagnostic tool
Authors: Rigo Fausto
Published: March 2005

The assessment of coronary flow reserve by transthoracic echocardiography has recently been introduced into clinical practice with gratifying results for the diagnosis of left anterior descending artery disease simultaneously reported by several independent laboratories. This technological novelty is changing the practice of stress echo for 3 main reasons. First, adding coronary flow reserve to regional wall motion allows us to have – in the same sitting – high specificity (regional wall motion) and a high sensitivity (coronary flow reserve) diagnostic marker, with an obvious improvement in overall diagnostic accuracy. Second, the technicalities of coronary flow reserve shift the balance of stress choice in favour of vasodilators, which are a more robust hyperemic stress and are substantially easier to perform with dual imaging than dobutamine or exercise. Third, the coronary flow reserve adds a quantitative support to the exquisitely qualitative assessment of wall motion analysis, thereby facilitating the communication of stress echo results to the cardiological world outside the echo lab. The next challenges involve the need to expand the exploration of coronary flow reserve to the right and circumflex coronary artery and to prove the additional prognostic value – if any – of coronary flow reserve over regional wall motion analysis, which remains the cornerstone of clinically-driven diagnosis in the stress echo lab.
Anthrax vaccine design: strategies to achieve comprehensive protection against spore, bacillus, and toxin
Authors: Wang Julia Y , Roehrl Michael H
Published: March 2005

The successful use ofBacillus anthracisas a lethal biological weapon has prompted renewed research interest in the development of more effective vaccines against anthrax. The disease consists of three critical components: spore, bacillus, and toxin, elimination of any of which confers at least partial protection against anthrax. Current remedies rely on postexposure antibiotics to eliminate bacilli and pre- and postexposure vaccination to target primarily toxins. Vaccines effective against toxin have been licensed for human use, but need improvement. Vaccines against bacilli have recently been developed by us and others. Whether effective vaccines will be developed against spores is still an open question. An ideal vaccine would confer simultaneous protection against spores, bacilli, and toxins. One step towards this goal is our dually active vaccine, designed to destroy both bacilli and toxin. Existing and potential strategies towards potent and effective anthrax vaccines are discussed in this review.
Tyrosine phosphorylation of myosin heavy chain during skeletal muscle differentiation: an integrated bioinformatics approach
Authors: Harney DF , Butler RK , Edwards RJ
Published: March 2005

Background

Previously it has been shown that insulin-mediated tyrosine phosphorylation of myosin heavy chain is concomitant with enhanced association of C-terminal SRC kinase during skeletal muscle differentiation. We sought to identify putative site(s) for this phosphorylation event.

Results

A combined bioinformatics approach of motif prediction and evolutionary and structural analyses identified tyrosines163 and 1856 of the skeletal muscle heavy chain as the leading candidate for the sites of insulin-mediated tyrosine phosphorylation.

Conclusion

Our work is suggestive that tyrosine phosphorylation of myosin heavy chain, whether in skeletal muscle or in platelets, is a significant event that may initiate cytoskeletal reorganization of muscle cells and platelets. Our studies provide a good starting point for further functional analysis of MHC phosphor-signalling events within different cells.
Satellite remote sensing of forest resources: three decades of research development
Authors: Boyd D. S. , Danson F. M.
Published: March 2005

Three decades have passed since the launch of the first international satellite sensor programme designed for monitoring Earth’s resources. Over this period, forest resources have come under increasing pressure, thus their management and use should be underpinned by information on their properties at a number of levels. This paper provides a comprehensive review of how satellite remote sensing has been used in forest resource assessment since the launch of the first Earth resources satellite sensor (ERTS) in 1972. The use of remote sensing in forest resource assessment provides three levels of information; namely (1) the spatial extent of forest cover, which can be used to assess the spatial dynamics of forest cover; (2) forest type and (3) biophysical and biochemical properties of forests. The assessment of forest information over time enables the comprehensive monitoring of forest resources. This paper provides a comprehensive review of how satellite remote sensing has been used to date and, building on these experiences, the future potential of satellite remote sensing of forest resources is highlighted.
A critical review of catchment-scale stream rehabilitation programmes
Authors: Hillman Mick , Brierley Gary
Published: March 2005

The development of catchment-scale stream rehabilitation programmes in many parts of the world marks a shift from the application of reach-based engineering principles towards an adoption of ecosystem-centred, adaptive and participatory approaches to river management. From a biophysical viewpoint, this represents recognition of the importance of the inherent geodiversity of aquatic ecosystems and the benefits that are gained through enhancing natural recovery mechanisms. As this approach to river management matures, it is important that its key elements and assumptions are subjected to critical appraisal. In this paper, the main features of contemporary catchment-wide programmes are examined through a review of pertinent literature and through examination of various case studies from North America, Europe, Asia and Australia. Emerging challenges and tensions include those of generating an authentic and functional biophysical vision at the catchment scale, of developing a proactive adaptive management approach, of achieving genuine community participation and of integrating biophysical and social factors in a transdisciplinary framework. Issues of scale, natural variability and complexity must be addressed in meeting these challenges.
In end-stage renal failure, does infection lead to elevated plasma aluminium and neurotoxicity? Implications for monitoring
Authors: Fenwick Sean , Roberts Edward A , Mahesh Balakrishna S , Roberts Norman B
Published: March 2005

The well-described long-term effects of sustained exposure to aluminium in patients with end-stage renal failure (ESRF) are a result of uptake and storage of aluminium, leading to cellular toxicity. A case is presented suggesting that this aluminium may be mobilizable, and indicating the consequence of such release.

A patient on haemodialysis (HD) presented acutely with infection, a raised CRP, decreased conscious level, impaired cognition and agitation. Subsequent neurological recovery over six to seven days appeared to follow the return of markedly elevated plasma aluminium concentrations to basal (i.e. from 25.2 μmol/L to 2.5 μmol/L; reference range <0.5 μmol/L), coupled with a resolution of the infection. The patient was on long-term aludrox therapy 3 g/day, and showed relative resistance to the exogenous hormone erythropoietin, resulting in a refractory anaemia and suggesting aluminium toxicity. A series of HD patients ( n=5) presenting with bacteraemia, not on aludrox, showed no appreciable rise in the plasma aluminium mean of 1.3 μmol/L (SD 0.9; range 0.6-2.0 μmol/L). We suggest that infection can result in release of tissue aluminium, leading to acutely elevated plasma aluminium concentrations and signs of neurotoxicity. The amount of tissue storage and resultant aluminium release seemed to be related to the use of aluminium hydroxide as a phosphate binder.
Malondialdehyde, glutathione, glutathione peroxidase and homocysteine levels in type 2 diabetic patients with and without microalbuminuria
Authors: Ozdemır Gülsen , Ozden Meltem , Maral Hale , Kuskay Sevinc , Cetınalp Pinar , Tarkun Ilhan
Published: March 2005

Background: High levels of homocysteine and oxidative stress are known to be associated with premature vascular disease in type 2 diabetes mellitus (DM). The aim of this study was to estimate homocysteine levels and oxidant-antioxidant status and to determine the relationship between them in type 2 diabetic patients with and without microalbuminuria.

Methods: Fasting blood samples were obtained from 48 diabetic patients (17 with and 31 without microalbuminuria) and 20 healthy subjects. Serum total homocysteine (tHcy), plasma malondialdehyde (MDA) erythrocyte glutathione (GSH) and glutathione peroxidase (GPx) activity were measured in these patients and the results were compared with those of controls who were chosen among healthy subjects.

Results: MDA levels were found to be significantly lower and GSH levels and GPx activities were found to be significantly higher in control subjects when compared with patients with and without microalbuminuria (MDA: P<0.0001, P<0.0001; GSH: P<0.0001, P<0.0001; GPx: P<0.0001, P<0.001, respectively). MDA levels were found to be significantly higher in patients with microalbuminuria compared with patients without microalbuminuria ( P<0.0001), while similarly GSH levels were found to be significantly lower in patients with microalbuminuria ( P<0.0001). Although there were no significant differences with respect to tHcy levels and GPx activities between the microalbuminuric and normoalbuminuric patients ( P>0.05), there was a significant difference with respect to tHcy levels between healthy controls and patients with microalbuminuria ( P<0.05). The serum levels of tHcy correlated best with plasma MDA and erythrocyte GSH concentrations in all diabetic patients ( r=0.549, P<0.0001; r=0.385, P<0.01).

Conclusion: Decreased antioxidant levels, increased lipid peroxidation and increased tHcy levels were observed in patients with microalbuminuria. These changes may contribute to vascular disease, which is particularly prevalent in type 2 DM patients with microalbuminuria.
GC/MS identification of toxic pyrrolizidine alkaloids in traditional remedies given to two sets of twins
Authors: Conradie Johan , Stewart Michael J , Steenkamp Vanessa
Published: March 2005

Neo- and perinatal mortality is high in most of Africa. Twins are at particular risk of perinatal mortality. The contribution of traditional remedies is seldom addressed. The case histories of two sets of twins who were treated with traditional remedies are described. The herbal remedies were analysed using gas chromatography-mass spectrometry. In one family, both siblings survived, albeit with hepatic damage. In the other family, one twin died within 24 h and the second one month after admission with a diagnosis of veno-occlusive liver disease (VOD). In both cases, the presence of the toxic pyrrolizidine alkaloid retrorsine, which is known to lead to VOD, was identified. Health-care workers should be aware of the possibility of traditional medicine administration as a cause of illness, specifically in twin births.
Detection and identification of low-concentration M proteins with CZE/IS; a 'dry' analysis
Authors: Keularts Irene MLW , Beunis Marlene H , van Oord John , Janssen Johannes W
Published: March 2005

The accuracy of detection and identification of low-concentration M proteins using capillary zone electrophoresis/immunosubtraction (CZE/IS) plots was systematically studied. To this end, 49 CZE plots (protein spectra; session I) and CZE/IS plots (spectra with corresponding immunosubtraction plots; session II) were judged by participants from 12 Dutch laboratories. Plots were based on mixed sera with a low concentration (0.4, 1 or 4 g/L) of one M protein, as well as normal sera, sera with an oligoclonal or polyclonal increase in immunoglobulins, and sera containing free monoclonal light chains.

At 0.4 g/L, nine out of 12 (9/12) different M proteins were hard to detect. At 1 g/L, 6/12 M proteins were detected by >85% of the participants. At 4 g/L, 10/12 M proteins were detected by all participants. Normal spectra were always judged correctly. At 1 g/L and 4 g/L, detected M proteins were identified correctly by 92% of the participants, versus only 63% at 0.4 g/L. The detection accuracy was only slightly (non-significantly) improved by the application of IS plots. Our data indicate that CZE/IS is applicable for most M proteins at concentrations ≥4 g/L.
A national survey amongst UK otolaryngologists regarding the treatment of Ménière’s disease
Authors: Smith W K , Sankar V , Pfleiderer A G
Published: March 2005

Since Dr Prosper Ménière described the vertiginous syndrome that now bears his name, a large variety of medical and surgical treatments have been introduced. To determine the way in which this condition is currently managed in the United Kingdom, a postal survey amongst consultant otolaryngologists was carried out. It revealed that 52 per cent were actively involved in the treatment of patients with Ménières disease using a wide range of medical and surgical therapies that have little or no evidence base. The survey found that 94 per cent of surgeons prescribe betahistine, 63 per cent diuretics and 71 per cent advise salt restriction to their patients, while 52 per cent of surgeons continue to recommend saccus decompression and 50 per cent are still inserting a grommet. However, two thirds of respondents now advocate the use of gentamicin therapy despite it only being introduced to this country just over 10 years ago. The results of this study and their relevance to the recommended present day management of Ménière’s disease are discussed.
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) presenting with sudden sensorineural hearing loss
Authors: Phillips John S , King Jacquelyn A , Chandran Siddharthan , Prinsley Peter R , Dick David
Published: March 2005

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is an autosomal dominant angiopathy characterized by recurrent cerebrovascular events, migraine and dementia. We describe a case of sensorineural hearing loss as the presenting feature of this condition. We have found no previous reports in the world literature of CADASIL presenting with a sudden sensorineural hearing loss. The significance of questioning a patient with regard to family history is exemplified in this case.
Simultaneous antrochoanal and sphenochoanal polyps: a rare clinical entity
Authors: Ozcan Muge , Ozlugedik Samet , Ikinciogullari Aykut
Published: March 2005

Choanal polyps almost always appear as solitary growths and most commonly arise from the maxillary sinus. Sphenochoanal and ethmoidochoanal polyps are extremely rare. Co-existence of more than one choanal polyp is even more infrequent. We present a patient with an antrochoanal and an accompanying sphenochoanal polyp for the first time in the literature. We discuss the clinical presentation, pathogenesis and surgical management of this rare clinical entity.
Parapharyngeal metastasis from papillary thyroid carcinoma: a case diagnosed by thyroglobulin measurement in peroral fine-needle aspiration of a cystic metastatic lymph node
Authors: Tomoda Chisato , Matsuzuka Fumio , Miyauchi Akira
Published: March 2005

We report a case of a parapharyngeal cystic metastatic lymph node arising from papillary thyroid carcinoma (PTC). Parapharyngeal metastases arising from PTC are rare and correct diagnosis of the parapharyngeal mass before surgery is difficult. In this case, the diagnosis of a parapharyngeal mass was made pre-operatively by thyroglobulin measurement in peroral fine-needle aspiration with negative cytology.