bluuebunny/crossref_metadata_2025_split huggingface dataset:
EXCITATION–CONTRACTION COUPLING FROM THE 1950s INTO THE NEW MILLENNIUM
Authors: Dulhunty AF 
Published: August 2006

SUMMARY

Excitation–contraction coupling is broadly defined as the process linking the action potential to contraction in striated muscle or, more narrowly, as the process coupling surface membrane depolarization to Ca2+ release from the sarcoplasmic reticulum.
We now know that excitation–contraction coupling depends on a macromolecular protein complex or ‘calcium release unit’. The complex extends the extracellular space within the transverse tubule invaginations of the surface membrane, across the transverse tubule membrane into the cytoplasm and then across the sarcoplasmic reticulum membrane and into the lumen of the sarcoplasmic reticulum.
The central element of the macromolecular complex is the ryanodine receptor calcium release channel in the sarcoplasmic reticulum membrane. The ryanodine receptor has recruited a surface membrane L‐type calcium channel as a ‘voltage sensor’ to detect the action potential and the calcium‐binding protein calsequestrin to detect in the environment within the sarcoplasmic reticulum. Consequently, the calcium release channel is able to respond to surface depolarization in a manner that depends on the Ca2+ load within the calcium store.
The molecular components of the ‘calcium release unit’ are the same in skeletal and cardiac muscle. However, the mechanism of excitation–contraction coupling is different. The signal from the voltage sensor to ryanodine receptor is chemical in the heart, depending on an influx of external Ca2+ through the surface calcium channel. In contrast, conformational coupling links the voltage sensor and the ryanodine receptor in skeletal muscle.
Our current understanding of this amazingly efficient molecular signal transduction machine has evolved over the past 50 years. None of the proteins had been identified in the 1950s; indeed, there was debate about whether the molecules involved were, in fact, protein. Nevertheless, a multitude of questions about the molecular interactions and structures of the proteins and their interaction sites remain to be answered and provide a challenge for the next 50 years.
BEHAVIOURAL TESTING AND HISTOLOGICAL ASSESSMENTS OF RABBIT SPINAL CORD FOLLOWING INTRATHECAL ADMINISTRATION OF ONDANSETRON
Authors: Lacassie Hector J , Schultz John R , Cummings Thomas J , Morris Richard , Trasti Scott L , Reynolds James D 
Published: August 2006

SUMMARY

Intrathecal injection of ondansetron has the potential to reduce opioid‐related side‐effects. The aim of the present study was to determine whether this route of administration produces neuraxial injury.
Adult, non‐pregnant female New Zealand white rabbits received a single bolus injection of a low (40 mg) or high (4.0 mg) dose of ondansetron into the intrathecal space between the 4th and 5th lumbar vertebrae. In some cases, ondansetron was coadministered with morphine (5 mg/kg). Control animals received a bolus injection of normal saline. Behavioural assessments were conducted at 1 and 24 h to determine overt changes in arousal and mobility, followed by histological evaluation of the excised spinal cord.
Of 45 animals investigated, 10 rabbits exhibited modest behavioural evidence of spinal injury, the incidence of which was equally distributed between the treatment groups. Haematoxylin and eosin, along with HAM56, staining of cross‐sections of the cervical, thoracic and upper and lower lumbar areas revealed mild signs of inflammation. This, too, was equally distributed between the treatment groups, suggesting that any observed neuraxial injury was the result of needle trauma and not ondansetron neurotoxicity.
Collectively, these negative findings support conducting further experiments to fully assess the clinical usefulness of intrathecal ondansetron administration.
POSSIBLE ANTIDIABETIC AND ANTIHYPERLIPIDAEMIC EFFECT OF FERMENTED PARKIA BIGLOBOSA (JACQ) EXTRACT IN ALLOXAN‐INDUCED DIABETIC RATS§
Authors: Odetola AA , Akinloye O , Egunjobi C , Adekunle WA , Ayoola AO 
Published: August 2006

SUMMARY

The hypoglycaemic effect of fermented seeds of Parkia biglobosa (PB; African locust bean), a natural nutritional condiment that features frequently in some African diets as a spice, was investigated in the present study in alloxan‐induced diabetic rats. Its effect was compared with that of glibenclamide (Daonil; Sanofi‐Aventis, Paris, France), a reference antidiabetic drug. The effects of PB on lipid profiles were also examined.
In order to assess the hypoglycaemic and hypolipidaemic effects of aqueous and methanolic extracts of PB on experimental animals, fasting plasma glucose (FPG), total cholesterol, triglyceride, high‐density lipoprotein (HDL) and low‐density lipoprotein (LDL) were determined. In addition, the weight of each animal was determined to assess any possible weight gain or loss in the experimental animals (diabetic rats treated with Daonil (group C), the aqueous extract of PB (group D) or the methanolic extract of PB (group E)) compared with control groups (non‐diabetic (group A) and non‐treated diabetic (group B)).
A single dose of 120 mg/kg, i.v., alloxan administered to rats resulted in significant increases in the FPG (P < 0.001) of test animals compared with controls. However, dietary supplementation with PB (6 g/kg extract for 4 weeks administered orally using an intragastric tube) ameliorated the alloxan‐induced diabetes in a manner comparable with that of the reference antidiabetic drug glibenclamide. Aqueous and methanolic extracts of PB (6% w/w) elicited 69.2% and 64.4% reductions, respectively, in FPG compared with 70.4% in 0.01 mg/150 g glibenclamide‐treated rats.
Although animals treated with the aqueous extract of PB gained weight in manner similar to normal controls, animals given the methanolic extract and glibenclamide lost weight in manner similar to non‐treated diabetic rats. In addition, high levels of HDL and low LDL were observed in animals treated with the aqueous extract of PB, a pattern similar to that seen in normal controls. Low levels of HDL and high levels of LDL were observed in animals treated with the methanolic extract of PB, a pattern similar to that seen in non‐treated diabetic controls.
The results of the present study demonstrate that both aqueous and methanolic extracts of fermented seeds of PB exert a hypoglycaemic effect; hence, PB has an antidiabetic property. However, only the aqueous extract of PB ameliorated the loss of bodyweight usually associated with diabetes. Although the aqueous extract has a favourable lipid profile, which is probably an indication of its possible anti‐arteriogenic property (hypertension and ischaemic heart diseases being common complications in diabetes mellitus), the methanolic extract shows possible contraindication to ischaemic heart diseases.
OMEGA‐3 FATTY ACIDS AND HYPERTENSION IN HUMANS
Authors: Mori Trevor A 
Published: August 2006

SUMMARY

Population studies and clinical trials provide compelling evidence that omega‐3 (w3) fatty acids have cardioprotective effects. The strongest evidence is from DART and GISSI‐P, two secondary prevention trials in patients with previous myocardial infarctions. Data from these trials support a reduction in ventricular fibrillation as a primary mechanism for the decreased incidence of myocardial infarction.
Evidence suggests that w3 fatty acids may also provide protection against stroke, particularly ischaemic stroke.
The cardioprotective effects of w3 fatty acids relate to improvements in blood pressure, cardiac function, arterial compliance and vascular function, as well as improved lipid metabolism, antiplatelet and anti‐inflammatory effects.
Clinical trials in humans have shown that eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have different haemodynamic properties. Docosahexaenoic acid may be more favourable in lowering blood pressure and heart rate, as well as improving vascular function. However, the effects of EPA and DHA may also differ depending on the target population.
ALCOHOL IS BAD FOR BLOOD PRESSURE
Authors: Puddey Ian B , Beilin Lawrence J 
Published: August 2006

SUMMARY

The regular consumption of alcohol elevates blood pressure, with global estimates that the attributable risk for hypertensive disease from alcohol is 16%.
The increase in blood pressure is approximately 1 mmHg for each 10 g alcohol consumed and is largely reversible within 2–4 weeks of abstinence or a substantial reduction in alcohol intake.
This increase in blood pressure occurs irrespective of the type of alcoholic beverage. In particular, the postulated effects of vasodilator flavonoid components of red wine to lessen or reverse alcohol‐related hypertension have not been borne out in intervention studies.
Heavy drinking, especially a binge pattern of drinking, is linked to a higher incidence of cerebral thrombosis, cerebral haemorrhage and coronary artery disease deaths, although a role for alcohol‐related hypertension in the causal pathway is not well defined.
In contrast, the light to moderate intake of alcohol has been consistently linked to a reduced risk of atherosclerotic vascular disease end‐points. Such a protective effect may also extend to hypertensive subjects.
However, the magnitude of any protective effect appears to have been exaggerated because of unmeasured confounders, especially diet, lifestyle and patterns of drinking. Furthermore, a decrease in overall mortality with drinking appears confined to older subjects and to populations with a high background cardiovascular risk profile.
Any putative cardiovascular benefits from drinking need to be carefully considered against the effects of alcohol to elevate blood pressure, together with many other adverse health consequences from drinking. Maximum cardiovascular benefit occurs at relatively low levels of consumption (i.e. one to two standard drinks a day in men (10–20 g alcohol) and up to one a day in women (10 g alcohol)). In hypertensive subjects, consumption beyond these levels would be unwise.
HYPERTENSION AND OXIDATIVE STRESS
Authors: Ward Natalie C , Croft Kevin D 
Published: August 2006

SUMMARY

Oxidative stress has been suggested to be involved in the pathogenesis of hypertension. This may be via a number of possible mechanisms, including quenching of the important vasodilator nitric oxide.
Animal studies have generally supported the hypothesis that increased blood pressure is associated with increased oxidative stress. However, human studies have been inconsistent and may differ owing to the populations studied and the various methods used. Treatment with anti‐oxidants has been suggested to lower oxidative stress and, therefore, blood pressure. However, to date, studies investigating single or combination supplements have failed to show any consistent benefit.
Overall, the evidence supporting the link between hypertension and oxidative stress remains inconclusive, with methodological and population differences possibly confounding results. Further studies investigating this relationship are warranted.
SPECIES VARIABILITY IN CARDIOVASCULAR RESEARCH: THE EXAMPLE OF ADRENOCORTICOTROPHIN‐INDUCED HYPERTENSION
Authors: Whitworth Judith A , Zhang Yi , Mangos George , Kelly John J 
Published: August 2006

SUMMARY

Lawrie Beilin has contributed greatly to international hypertension research through both animal and human studies.
Animals are used in biomedical research to gain insights that can be extrapolated ultimately to humans.
A simple experimental manipulation, adrenocorticotrophin (ACTH) administration, has a range of different cardiovascular effects in different species.
Caution should be exercised in extrapolating data from animals to humans.
Analysis of polymorphisms of tumor necrosis factor‐α and polymorphic xenobiotic metabolizing enzymes in inflammatory bowel disease: Study from northern India
Authors: Mittal Rama D , Manchanda Parmeet K , Bid Hemant K , Ghoshal Uday C 
Published: August 2006

AbstractBackground:  Tumor necrosis factor (TNF)‐α is a proinflammatory cytokine associated with inflammatory diseases, while GSTM1 and T1 enzymes catalyze detoxification of products of oxidative stress and hence reduce inflammation. Thus, both may play important roles in the pathogenesis of inflammatory bowel disease (IBD). The present study aimed to evaluate the effect of polymorphism of the TNF‐α promoter at the −308 site, GSTM1 and GSTT1 in patients with IBD and healthy controls from northern India.Method:  Genotyping was performed in 114 patients with IBD (22 Crohn’s disease [CD] and 92 ulcerative colitis [UC]) in TNF‐α and 105 (20 CD and 85 UC) in GSTM1 and T1 and 164 healthy controls using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) and multiplex PCR methods.Results:  Patients with IBD were comparable to healthy controls in relation to age and gender. Genotypic and allelic frequencies of TNF‐α were comparable among patients with IBD and healthy controls. GSTM1 null genotype was more frequent in UC than in healthy controls (52/85 vs 49/164; P < 0.001) and GSTT1 null genotype was more frequent both in UC and CD as compared to healthy controls (77/85 and 18/20 vs 26/164, respectively; P < 0.001 for both). Frequency of combined null genotype in GSTM1 and T1 was more frequently associated with IBD than healthy controls (4/20 vs 8/164; P = 0.029, OR = 4.875 and 28/85 vs 8/164; P < 0.001, OR = 9.579, respectively).Conclusions:  ‘Null’ genotypes of GSTM1 and T1 are associated with IBD and the combination of the two GST genotypes further increases the risk, possibly due to gene–gene interaction. TNF‐α is unlikely to be an important determinant of susceptibility to IBD in the Indian population.
Up‐regulated eotaxin plasma levels in chronic liver disease patients indicate hepatic inflammation, advanced fibrosis and adverse clinical course
Authors: Tacke Frank , Trautwein Christian , Yagmur Eray , Hellerbrand Claus , Wiest Reiner , Brenner David A , Schnabl Bernd 
Published: August 2006

AbstractBackground and Aims: Recent studies highlight the role of chemokines for the attraction of inflammatory cells in liver injury and fibrogenesis. The CC chemokine ligand 11, eotaxin (CCL11), is up‐regulated in senescent human hepatic stellate cells and crucial in animal models of T‐cell mediated hepatitis. The aim of this study was to analyze the role of eotaxin in chronic liver disease.Methods: Plasma eotaxin levels of 111 patients with chronic liver disease were correlated with clinical presentation, laboratory parameters, liver histology and clinical course in a 6‐year follow‐up.Results: Eotaxin concentrations were significantly up‐regulated in patients with liver cirrhosis and increased according to Child–Pugh and model of end‐stage liver disease (MELD) score. Eotaxin correlated with the hepatic biosynthetic capacity and other inflammatory cytokines. High eotaxin was associated with hepatic necroinflammation and fibrosis in liver histology. In patients with typical clinical complications of cirrhosis, eotaxin was found to be increased. High eotaxin indicated an unfavorable prognosis in 6‐year follow‐up.Conclusions: High eotaxin expression may be involved in the pathogenesis of chronic liver diseases. Plasma eotaxin levels correlate with the degree of liver cirrhosis and could serve as an additional biomarker indicating histological hepatic necroinflammation and fibrosis as well as an adverse clinical course.
Biliary tract malignancy and abnormal pancreaticobiliary junction in a Western population
Authors: Roukounakis Nicholas , Manolakopoulos Spilios , Tzourmakliotis Dimitrios , Bethanis Sotiris , McCarty Todd M , Cuhn Joseph 
Published: August 2006

AbstractBackground and Aim:  Abnormal pancreaticobiliary junction is a rare congenital disorder in which the junction of biliary and pancreatic duct is located outside the duodenal wall and forms a long common channel. The disorder has been associated with a high incidence of gallbladder cancer in Japanese studies. The aim of this study was to assess the frequency of abnormal pancreaticobiliary junction in a Western population and its association with biliary tract malignancies.Methods:  All endoscopic retrograde cholangiopancreatography examinations of 82 consecutive patients with gallbladder carcinoma or biliary duct cancer treated at Baylor University during a period of 10 years were analyzed. A further 220 consecutive patients with normal films or non‐malignant pancreaticobiliary disease acted as controls.Results:  Fifty‐eight (70.7%) patients were found to have adequate imaging of junction and were included in the analysis. These included 37 patients with common bile duct carcinoma and 21 with gallbladder carcinoma. Abnormal pancreaticobiliary junction (common channel ≥8 mm) was observed in 44.8% patients with biliary tract carcinoma compared to 6.2% of controls (P < 0.01). Eighteen had type I abnormality and eight type II. Seven patients had a cystic dilatation of the common bile duct, all with type I abnormality. Mean overall survival was 9.5 months. Survival did not differ significantly between patients with normal and abnormal junctions (P = 0.1).Conclusions:  The results suggest a close association between the anatomy of the distal ends of the common bile duct and main pancreatic duct and development of biliary tract carcinoma in Western populations.
On conflict, containment and the relationship between them
Authors: Bowers Len 
Published: August 2006

A programme of research into conflict (e.g. violence, absconding, medication refusal) and containment (e.g. seclusion, special observation, physical restraint) in inpatient psychiatry has been under way at City University, London, UK, for the past 10 years. Recent research findings, plus the challenges posed by ongoing projects, have made apparent the need for greater clarity about the overarching concepts of ‘conflict’ and ‘containment’. This paper pulls together research findings pertaining to this issue, and conducts a reasoned analysis of what common characteristics might underlie ‘conflict’ and ‘containment’. It is concluded that these are patient threats to safety, and the staff maintenance of safety. Details are presented on the inclusions and exclusions that follow from taking such a position, and potential definitions offered. On the grounds of this conceptual analysis, plus evidence for moderate degrees of statistical association between behaviours and events in each domain, it is concluded that it is legitimate to conduct analyses at the level of total conflict and containment rates, as well as at the level of individual types of behaviours and events (e.g. verbal abuse, sedation). Some of the mathematical difficulties in the analysis of total conflict and containment are addressed, and results of a weighting exercise presented. This exercise challenges our perception of the severity of some containment measures that are becoming more commonly used in acute psychiatry.
Has Finance Made the World Riskier?
Authors: Rajan Raghuram G. 
Published: August 2006

Abstract Developments in the financial sector have led to an expansion in its ability to spread risks. The increase in the risk bearing capacity of economies, as well as in actual risk taking, has led to a range of financial transactions that hitherto were not possible, and has created much greater access to finance for firms and households. On net, this has made the world much better off. Concurrently, however, we have also seen the emergence of a whole range of intermediaries, whose size and appetite for risk may expand over the cycle. Not only can these intermediaries accentuate real fluctuations, they can also leave themselves exposed to certain small probability risks that their own collective behaviour makes more likely. As a result, under some conditions, economies may be more exposed to financial‐sector‐induced turmoil than in the past. The paper discusses the implications for monetary policy and prudential supervision. In particular, it suggests market‐friendly policies that would reduce the incentive of intermediary managers to take excessive risk.
Bidder CEO and Other Executive Compensation in UK M&As
Authors: Coakley Jerry , Iliopoulou Stavroula 
Published: August 2006

Abstract This paper investigates the impact of M&As on bidder (CEO and other) executive compensation employing a unique sample of 100 completed bids in the UK over the 1998–2001 period. Our findings indicate that less independent and larger boards award CEOs significantly higher bonuses and salary following M&A completion both for the full sample and for the UK and US sub‐samples. UK CEOs and executives are rewarded more for the effort exerted in accomplishing intra‐industry or large mergers than for diversifying or small mergers and their cash pay is unaffected by other measures of their managerial skill or performance. US bidders are rewarded at higher levels than their UK counterparts and their remuneration is related only to measures of CEO dominance over the board of directors. Overall our findings offer support for the managerial power rather than the agency theory perspective on managerial compensation.
Sexual selection in hermit crabs: a review and outlines of future research
Authors: Contreras‐Garduño J. , Córdoba‐Aguilar A. 
Published: August 2006

AbstractThe information currently available on sexual selection in hermit crabs is reviewed to identify the role of males and females before, during and after mating. According to this information, possible mechanisms of male–male competition, female choice and/or sexual conflict are suggested. Important male components that may affect mating success include dragging the female shell, rotations of the female's shell and male cheliped palpations, and male size and/or shell characteristics (species and size). Possible female determinants of male mating/fertilization success include size (as an indicator of egg production capacity), signalling of sexual receptivity to males, delay from mate guarding to copulation and mating duration. Avenues for deeper exploration in males include the role of the number and morphometry of male sexual tubes during sperm transfer, and whether ejaculate size and sperm number can be adjusted with variable situations of sperm competition intensity and risk. In females it would be interesting to investigate the chemical and behavioural mechanisms affecting spermatophore breakage for sperm release and the variable duration from sperm transfer to spawning. Given these possibilities, and that sperm is externally deposited on the female's body but inside her shell (except for those species that do not use shells, e.g. Birgus, or species where shells are rather small and do not cover the body totally, e.g. Parapagurus), we conclude that hermit crabs are unique subjects for separating male and female effects, particularly with respect to the applicability of current ideas in sexual selection such as female choice and sexual conflict. Some practical ideas are provided to disentangle both hypotheses using these animals.
Necks for sex: sexual selection as an explanation for sauropod dinosaur neck elongation
Authors: Senter P. 
Published: August 2006

AbstractThe immensely long neck of a sauropod is one of the most familiar and striking of anatomical specializations among dinosaurs. Here, I use recently collected neontological and paleontological information to test the predictions of two competing hypotheses proposed to explain the significance of the long neck. According to the traditional hypothesis, neck elongation in sauropods increased feeding height, thereby reducing competition with contemporaries for food. According to the other hypothesis, which is advanced for the first time here, neck elongation in sauropods was driven by sexual selection. Available data match the predictions of the sexual selection hypothesis and contradict the predictions of the feeding competition hypothesis. It is therefore more plausible that increases in sauropod neck lengths were driven by sexual selection than by competition for foliage.