bluuebunny/crossref_metadata_2025_split huggingface dataset:
TRANSLATION OF SALT RETENTION TO CENTRAL ACTIVATION OF THE SYMPATHETIC NERVOUS SYSTEM IN HYPERTENSION
Authors: Brooks Virginia L , Haywood Joseph R , Johnson Alan Kim 
Published: April 2005

SUMMARY1. Increased dietary salt increases blood pressure in many hypertensive individuals, producing salt‐sensitive hypertension (SSH). The cause is unknown, but a major component appears to be activation of the sympathetic nervous system. The purpose of this short review is to present one hypothesis to explain how increased dietary salt increases sympathetic activity in SSH.2. It is proposed that increased salt intake causes salt retention and raises plasma sodium chloride (NaCl) concentrations, which activate sodium/osmoreceptors to trigger sympathoexcitation. Moreover, we suggest that small and often undetectable increases in osmolality can drive significant sympathoexcitation, because the gain of the relationship between osmolality and increased sympathetic activity is enhanced. Multiple factors may contribute to this facilitation, including inappropriately elevated levels of angiotensin II or aldosterone, changes in gene expression or synaptic plasticity and increased sodium concentrations in cerebrospinal fluid.3. Future studies are required to delineate the brain sites and mechanisms of action and interaction of osmolality and these amplification factors to elicit sustained sympathoexcitation in SSH.
THERMOREGULATORY ROLE OF PERIVENTRICULAR TISSUE SURROUNDING THE ANTEROVENTRAL THIRD VENTRICLE (AV3V) DURING ACUTE HEAT STRESS IN THE RAT
Authors: Whyte Douglas G , Johnson Alan Kim 
Published: April 2005

SUMMARY1. Thermoregulatory effector mechanisms are strongly influenced by hydration status. Dehydration delays the onset of evaporative heat loss and the redistribution of cardiac output in response to elevations in core temperature, yet very little is known about how and where thermal and non‐thermal information is integrated.2. The anteroventral third ventricular (AV3V) region encompasses several distinct neural structures, including the organum vasculosum of the lamina terminalis, the median preoptic nucleus, the preoptic periventricular nucleus and the medial aspects of the medial preoptic nucleus. In addition to its well‐documented role in body fluid and cardiovascular homeostasis, recent anatomical and in vitro evidence has indicated the AV3V region may also be pivotal in the integration of thermal and osmotic information.3. Electrolytic lesions of the AV3V region produce a markedly reduced thermal tolerance in rats. Elevations in mean arterial pressure, heart rate and mesenteric resistance were all attenuated in the AV3V‐lesioned animals in response to a heat stress; however, hindquarter resistance was unaffected. Heat‐induced salivation was also attenuated, severely reducing the ability of rats to lose heat via evaporation.4. The AV3V region clearly has a functional role in thermoregulation, as well as cardiovascular and body fluid homeostasis. These data add further support to the hypothesis that thermal and non‐thermal information may be integrated within this region.
DECREASED VASODILATION INDUCED BY A NEW NITRIC OXIDE DONOR IN TWO KIDNEY, ONE CLIP HYPERTENSIVE RATS IS DUE TO IMPAIRED K+ CHANNEL ACTIVATION
Authors: Bonaventura Daniella , Oliveira Fabiana S , Da Silva Roberto S , Bendhack Lusiane M 
Published: April 2005

SUMMARY1. We studied the effect of the new compound trans‐[RuCl([15]aneN4)NO]2+ (15‐ane) in denuded aortic rings of two kidney (2K) normotensive and two kidney, one clip (2K‐1C) hypertensive rats.2. The compound 15‐ane releases nitric oxide (NO) when reduced by a catecholamine (noradrenaline).3. Oxyhemoglobin (HbO2), an NO scavenger, completely abolished the effect of 15‐ane in both 2K and 2K‐1C rats, indicating that the relaxation is really due to NO release.4. We tested the hypothesis that an impairment of K+ channels plays an important role in the vasodilation induced by 15‐ane.5. The selective inhibitor of soluble guanylyl‐cyclase, namely 1H‐[1,2,4]oxadiazolo[4,3‐alpha]quinoxalin‐1‐one (ODQ; 1 µmol/L) reduced the relaxation induced by 15‐ane. In 2K‐1C rat aortic rings, ODQ reduced the maximum effect (Emax) of 15‐ane, whereas in 2K rat aortic rings ODQ reduced Emax and pD2 values to 15‐ane.6. The selective K+ channel blockers glibenclamide (blocks KATP; 3 µmol/L), 4‐aminopyridine (blocks KV; 1 mmol/L) and the small conductance KCa channel blocker apamin (1 µmol/L) reduced Emax and pD2 values for 15‐ane‐induced relaxation responses of aortas from 2K rats. However, iberiotoxin, a blocker of large conductance KCa channels, reduced only the Emax to 15‐ane. None of these K+ channel blockers had any effect on the relaxation induced by 15‐ane of aortas from 2K‐1C rats.7. These data indicate that an impaired functional activity of K+ channels contributes to the deficient relaxation induced by the NO donor 15‐ane in renal hypertensive 2K‐1C rat aortas.
ROLE OF ENDOTHELIUM‐DERIVED HYPERPOLARIZING FACTOR IN ENDOTHELIAL DYSFUNCTION DURING DIABETES
Authors: Fitzgerald Sharyn M , Kemp‐Harper Barbara K , Tare Marianne , Parkington Helena C 
Published: April 2005

SUMMARY1. Under normal conditions, the endothelium plays a major role in the maintenance of vasodilatory tone via the production of endothelium‐derived vasodilator agents, such as prostacyclin, nitric oxide and endothelium‐derived hyperpolarizing factor (EDHF). Inhibition of endothelium‐dependent relaxation features prominently in a range of cardiovascular diseases, including hypertension, coronary artery disease and diabetes.2. Endothelium‐derived hyperpolarizing factor is a prominent vasodilator, particularly in smaller arteries and arterioles. There is now emerging evidence to suggest that EDHF may play a role in the endothelial dysfunction in diabetes.3. Since the first description of endothelium‐dependent hyperpolarization some 20 years ago, it has emerged that EDHF is heterogeneous in nature, consisting of diffusible factors and contact‐mediated mechanisms. The specific identity of EDHF in any particular vascular bed may influence the impact of diabetes on vascular function.4. There is accumulating evidence in diabetic rat models and humans showing impaired EDHF activity in small resistance vessels. In contrast, studies in mice suggest that EDHF activity is actually enhanced under diabetic conditions.5. It is clear that alterations in EDHF activity may have an important contribution in diabetes, more specifically in contributing to microvascular complications observed under diabetic conditions.
A HAPLOTYPE OF THE ANGIOTENSINOGEN GENE IS ASSOCIATED WITH HYPERTENSION IN AFRICAN AMERICANS
Authors: Kumar Ashok , Li Yanna , Patil Sai , Jain Sudhir 
Published: April 2005

SUMMARY1. Hypertension is a serious risk factor for myocardial infarction, heart failure, vascular disease, stroke and renal failure. The incidence of hypertension is 25–30% in the adult Caucasian population and complications due to hypertension are even greater in African Americans.2. The renin–angiotensin system plays an important role in the regulation of blood pressure and previous studies have suggested that angiotensinogen (AGT) gene locus is linked with human essential hypertension. Earlier studies suggested that a single nucleotide polymorphism (SNP) that converts methionine to threonine at amino acid 235 is associated with hypertension in the Caucasian population. However, this SNP is not associated with hypertension in African American and Chinese populations.3. We have found an A/G polymorphism at −217 of the human AGT gene promoter and have shown that the frequency of allele A at −217 is significantly increased in the genomic DNA of African American hypertensive patients.4. We have also shown that: (i) reporter constructs containing the AGT gene promoter with nucleoside A at −217 have increased promoter activity on transient transfection; and (ii) the CCAAT box enhancer binding protein (C/EBP) family of transcription factors and glucocorticoid receptor (GR) bind preferentially to this region of the promoter when nucleoside A is present at −217. In addition, variant −217A is always present with variants −532T, −793A and −1074T in the human AGT gene promoter.5. These data suggest that the AGT haplotype containing −217A, −532T, −793A and −1074T may be involved in increased transcription of this gene and may play a role in human hypertension.
CARDIOVASCULAR AUTONOMIC REGULATION IN SUBJECTS WITH NORMAL BLOOD PRESSURE, HIGH–NORMAL BLOOD PRESSURE and RECENT‐ONSET HYPERTENSION
Authors: Prakash E Sankaranarayanan ,   Madanmohan,, Sethuraman K Raman , Narayan Sunil K 
Published: April 2005

SUMMARY1. In the present study, we tested the hypothesis that heart rate variability (HRV) is reduced in recent‐onset hypertension and that pressor responses to standard autonomic reflex tests are not any different in hypertensives compared with normotensives. We also hypothesized that subjects with high–normal blood pressure (BP) would be distinguishable from normotensives on the basis of short‐term HRV indices.2. Three groups of subjects, each consisting of 15 men and 10 women, were examined. The first group consisted of subjects with recent‐onset hypertension who were not taking antihypertensive medication (mean (±SD) age 50 ± 12 years; BP ≥ 140/90 mmHg), the second group consisted of subjects with high–normal BP (mean age 46 ± 13 years; BP 130–139/85–89 mmHg) and the third group consisted of subjects with normal BP (mean age 48 ± 12 years; BP < 120/80 mmHg). The aim was to characterize the autonomic state in each group.3. Blood pressure, heart rate (HR), indices of short‐term HRV during supine rest and quiet standing, HR variation during timed deep breathing (HRVdb) and pressor responses to the cold pressor test and sustained isometric handgrip were compared between the groups.4. Although the three groups were comparable (P > 0.1) in terms of mean HR and low‐frequency (LF) power expressed in normalized units at rest and during quiet standing, the standard deviation of normal‐to‐normal RR intervals (SDNN) during supine rest, LF and high‐frequency spectral powers during supine rest and HRVdb were lowest in hypertensives (P ≤ 0.05 for each), indicating diminished baroreflex modulation of RR intervals in hypertensives.5. In contrast, LF power was highest in subjects with high–normal BP (P ≤ 0.05) during supine rest and this is possibly because of higher BP variability.6. The results suggest that HRVdb provides a simple measure of cardiac vagal effects in hypertensives, the rate–pressure product provides a simple measure of overall HRV in hypertensives and, in clinical hypertension, the arterial baroreflex mechanism is reset to maintain a higher BP through diminished vagal modulation of HR and possibly heightened sympathetic outflow to the heart and resistance vessels.
When Promoters Like Scalpers
Authors: Karp Larry , Perloff Jeffrey M. 
Published: April 2005

If a monopoly supplies a perishable good, such as tickets to a performance, and is unable to price discriminate within a period, the monopoly may benefit from the potential entry of resellers. If the monopoly attempts to intertemporally price discriminate, the equilibrium in the game among buyers is indeterminate when the resellers are not allowed to enter, and the monopoly's problem is not well defined. An arbitrarily small amount of heterogeneity of information among the buyers leads to a unique equilibrium. We show how the potential entry of resellers alters this equilibrium.
The moment a performance begins, that seat is dead … . It's like fruit. It's perishable.— Jeffrey Seller, producer of Rent.

New York Times, July 20, 2003.
Sequence variations in rgpA and rgpB of Porphyromonas gingivalis in periodontitis
Authors: Beikler T. , Peters U. , Prior K. , Ehmke B. , Flemmig T. F. 
Published: April 2005

Objective:  The aim of the present study was to determine sequence variations in the active centre of the Arg‐X‐specific protease encoding genes rgpA and rgpB of clinical Porphyromonas gingivalis isolates and to analyse their prevalence in periodontitis patients before and 3 months after mechanical periodontal therapy.Background:  Genetic diversity at nucleotides 281, 283, 286 and 331 has been shown to result in amino acid substitutions in the catalytic domain of RgpA and RgpB that affect the substrate specificity and thus may influence the efficacy of Arg‐X‐protease specific inhibitors.Methods:  Sequence analysis of rgpA and rgpB genes in clinical P. gingivalis strains isolated from subgingival plaque samples of 82 periodontitis patients before and 3 months after mechanical supra‐ and subgingival debridement was performed.Results:  No specific variation within the rgpA sequence was observed. However, the rgpB sequence in the region of the active centre showed five different rgpB genotypes, which were named NYPN, NSSN, NSSK, NYPK and DYPN according to the derived amino acid substitution. Porphyromonas gingivalis genotype NYPN was detected in 27 patients (32.9%) before and in 8 patients (9.8%) after therapy, NSSN in 26 (31.7%) and 10 (12.2%), NSSK in 22 (26.8%) and 2 (2.4%), NYPK in 5 (6.2%) and 1 (1.2%), and DYPN in 1 patient (1.2%) and 0 patients (0%), respectively. Only one patient (1.2%) harboured two P. gingivalis rgpB genotypes (NSSK/NYPN) before treatment; these were no longer detected after therapy.Conclusion:  The results indicate that five rgpB genotypes are maintained in natural populations of P. gingivalis. These data may be of importance with regard to the development of specific rgpB inhibitors.
Longitudinal analysis of metalloproteinases, tissue inhibitors of metalloproteinases and clinical parameters in gingival crevicular fluid from periodontitis‐affected patients
Authors: Pozo P. , Valenzuela M. A. , Melej C. , Zaldívar M. , Puente J. , Martínez B. , Gamonal J. 
Published: April 2005

Background:  The aim of this work was to improve the assessment of the periodontal disease status through measurements of extracellular matrix metalloproteinases (MMPs) and their tissular inhibitors (TIMPs) in the gingival crevicular fluid from patients diagnosed with chronic periodontitis.Methods:  Gingival crevicular fluid samples from patients (n = 13) were taken from 60 sites initially, and from 51 and 41 sites, respectively, 3 and 6 months after scaling and root planing. Gingival crevicular fluid samples were also taken from healthy subjects (n = 11, 24 sites). The presence of MMP‐9 and MMP‐8 was assessed by zymography and immunowestern blotting, respectively. The actual MMP activity (gelatinase and collagenase) was measured using the fluorogenic substrate assay. TIMP‐1 and ‐2 levels were measured by immunodot blot.Results:  The fluorogenic substrate assay determinations showed higher MMP activity in sites with probing depth ≥ 4 mm, with significant reduction post‐treatment. Gelatinase activity followed by zymography consisted mainly of MMP‐9. A different pattern of MMP‐8 in control and patient sites was found. Controls only showed species of a partially active form (69 kDa), whereas patient sites showed a high frequency of the active form (56 kDa), and in some cases the latent form (85 kDa) was also observed. The active form reduced its frequency in sites with probing depth ≥ 4 mm. TIMP‐1 and ‐2 levels in patients were significantly lower than in controls, and after treatment the recovery of TIMP‐1 level similar to control was observed.Conclusion:  Significant correlations between the severity of the periodontal disease and the actual MMP activity, the active form of MMP‐8 and the low level of both TIMP‐1 and TIMP‐2 were found.
An in vitro model of chlorhexidine‐induced tooth staining
Authors: Carpenter G. H. , Pramanik R. , Proctor G. B. 
Published: April 2005

Background:  Tooth staining is a common feature of chlorhexidine treatment for periodontal disease and there is a large variation between patients as to the degree of their tooth staining. Although the mechanism of tooth staining is uncertain, diet, smoking and oral hygiene appear probable factors.Objectives:  This study investigated the role of saliva in chlorhexidine‐induced tooth staining and used tea as the staining agent in an in vitro model with hydroxyapatite mimicking teeth.Methods:  Saliva has been used to create an acquired pellicle and in solution to mimic its effects in vivo. Using different combinations of tea, chlorhexidine and parotid saliva, substances binding to hydroxyapatite were analysed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Using this system, tea, chlorhexidine and salivary proteins were clearly identifiable following staining by Coomassie Brilliant Blue.Results:  The results indicated that tea interacted with many salivary proteins, in particular proline‐rich proteins and histatins. Chlorhexidine did not appear to complex with or precipitate salivary proteins nor prevent the formation of an acquired pellicle on the hydroxyapatite. In isolation, tea and chlorhexidine bound in small amounts to hydroxyapatite, but when added in combination, binding of both to hydroxyapatite was greatly increased. The acquired pellicle reduced chlorhexidine and tea binding, but conversely increased the binding of either tea or chlorhexidine alone to hydroxyapatite.Conclusion:  In conclusion, salivary proteins play an important role in the staining process and the combination of tea and chlorhexidine appears to be a very potent staining factor.
Molecular analysis of human oral microbiota
Authors: Sakamoto Mitsuo , Umeda Makoto , Benno Yoshimi 
Published: April 2005

Objectives:  The application of molecular, mainly 16S ribosomal RNA (rRNA)‐based approaches enables researchers to bypass the cultivation step and has proven its usefulness in studying the microbial composition in a variety of ecosystems, including the human oral cavity. In this mini‐review, we describe the impact of these culture‐independent approaches on our knowledge of the ecology of the human oral cavity and provide directions for future studies that should emphasize the role of specific strains, species and groups of microbes in periodontal disease.Materials and methods:  Recent findings are summarized to elucidate the relationship between periodontal disease and human oral microbiota, including as‐yet‐to‐be‐cultured organisms.Results:  The real‐time polymerase chain reaction (PCR) method was developed to detect and quantify periodontopathic bacteria, such as Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis (formerly Bacteroides forsythus) and Treponema denticola. The checkerboard DNA–DNA hybridization technique allowed enumeration of large numbers of species in very large numbers of samples. 16S rRNA gene clone library analysis revealed the diversity of human oral microbiota and the existence of as‐yet‐to‐be‐cultured organisms that are presumed periodontal pathogens. In addition, terminal restriction fragment length polymorphism (T‐RFLP) analysis was applied for assessment of diversity of human oral microbiota.Conclusion:  Culture‐independent approaches are useful for studying the microbial ecology in the human oral cavity and should be useful in the future to elucidate the etiology of periodontal disease.
Three‐dimensional evaluation for augmented bone using guided bone regeneration
Authors: Tamura Takanori , Fukase Yasumasa , Goke Eiji , Yamada Yutaka , Sato Shuichi , Nishiyama Minoru , Ito Koichi 
Published: April 2005

Objective:  This study evaluated new bone regeneration beyond the skeletal envelope within an occlusive titanium cap on rabbit calvaria using microfocus computed tomography images.Methods:  In 10 rabbits, the calvaria was exposed and a circular groove was prepared. After penetrating the marrow, a standard hemispherical titanium cap was placed in the groove and covered with a cutaneous flap. After 1 or 3 months, the animals were killed and the calvariae and titanium caps were dissected. After taking microfocus computed tomography images of the specimens, histological sections were made. The specimens were observed using three‐dimensional images constructed from the microfocus computed tomography images, and the histological sections were examined to compute bone parameters.Results:  The three‐dimensional images and histological specimens showed that new bone formed in flat, cup‐like, and dome shapes. The bone parameters trabecular thickness and the proportion of marrow space to the capacity of the titanium cap increased, whereas bone density decreased, and there were significant differences between the 1‐ and 3‐month groups.Discussion:  First, a cylinder of new bone formed from the existing bone. Gradually, bone formed along the cap wall and the new tissue formed in a crater indented centrally. Finally, the new tissue formed in the shape of a dome.Conclusion:  Trabecular bone formed along the wall of the titanium cap, and bone filled the inside of the cap within 3 months.
Molecular Mechanism for Connective Tissue Destruction by Dipeptidyl Aminopeptidase IV Produced by the Periodontal PathogenPorphyromonas gingivalis
Authors: Kumagai Yumi , Yagishita Hisao , Yajima Ayako , Okamoto Tatsuya , Konishi Kiyoshi 
Published: April 2005

ABSTRACTPorphyromonas gingivalisis a pathogen associated with adult periodontitis. It produces dipeptidyl aminopeptidase IV (DPPIV), which may act as a virulence factor by contributing to the degradation of connective tissue. We investigated the molecular mechanism by which DPPIV contributes to the destruction of connective tissue. DPPIV itself did not show gelatinase or collagenase activity toward human type I collagen, but it promoted the activity of the host-derived matrix metalloproteinase 2 (MMP-2) (gelatinase) and MMP-1 (collagenase). DPPIV bound to fibronectin and mediated the adhesion ofP. gingivalisto fibronectin. Mutant DPPIV with catalytic Ser mutagenized to Ala (DPPSA) did not accelerate the degradation of collagen and gelatin by MMPs but retained fibronectin-binding activity. The adhesion of human gingival fibroblasts and NIH 3T3 cells to fibronectin was inhibited by DPPIV. Strain 4351ADPPSA exhibited an intermediate level of virulence in mice, between that of the strain expressing wild-type DPPIV (4351ADPP) and that of the strain harboring only the plasmid vector (4351AVEC). It is suggested that both activity promoting the degradation of collagen and gelatin and binding to fibronectin are required for full virulence. These results reveal novel biological functions of DPPIV and suggest a pathological role in the progression of periodontitis.
Physiological profile in relation to playing position of elite college Gaelic footballers
Authors: McIntyre M C , Hall M 
Published: April 2005

Objective:To examine the physiological profile, and its relation to playing position, of elite college Gaelic footballers.Method:The subjects were 28 elite Gaelic footballers (12 backs, 12 forwards, and four midfielders; mean (SD) age 21 (1.67) years), who won a major intervarsity tournament (Sigerson Cup) three times in succession.Results:There was general similarity among the members of the team, probably the result of a typical, common training programme. The team means for stature (1.81 (0.05) m), body mass index (81.6 (6.5)) and percentage body fat (14.5 (3.1)%), power output by Wingate test (absolute power 912 (152) W or 10.72 (1.6) W/kg) and sit and reach test (22.3 (5.5) cm) displayed no significant differences when analysed according to playing position. However, midfielders did have significantly larger body mass than backs (p<0.05) and greater maximal oxygen consumption (p<0.01) and greater vertical jumping ability than backs and forwards (vertical jump power output, p<0.01; vertical jump, p<0.01). Midfielders also had greater absolute handgrip strength (p<0.01).Conclusion:The differences exhibited by midfielders despite identical training suggests that they stem from physiological adaptation to competition rather than training.