bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of birth weight on coronary heart disease morbidity and mortality in a birth cohort followed up for 85 years: a population‐based study of men born in 1913
Authors: Eriksson M. , Wallander M.‐A. , Krakau I. , Wedel H. , Svärdsudd K.
Published: November 2004

Objectives. To analyse whether there is a relationship between birth weight on the one hand and coronary heart disease (CHD) and cardiovascular disease (CVD) mortality and morbidity on the other, whether such a relationship is influenced by potential modifying factors from the time of birth, adult height and the presence of diabetes, and what significance these possible associations might have for the CHD and CVD rates in the general population.

Design. Population‐based birth cohort.

Setting. Sweden.

Subjects. A total of 1319 singleton men born in 1913, surviving until age 20 and from then on followed until 85 years of age.

Main outcome measures. CHD and CVD mortality and morbidity events.

Results. The gestational age adjusted CHD and CVD mortality and morbidity hazard ratios were virtually unaffected by birth weight. Taking possible effect‐modifying variables into account did not change the results. The population attributable risk percentage for CHD and CVD mortality and morbidity due to a birth weight ≤3000 g was 1% or less.

Conclusions. Birth weight did not significantly affect CHD or CVD mortality or morbidity. A birth weight ≤3000 g contributes little to the burden of CHD and CVD on a community level.
Internalization of the human CRF receptor 1 is independent of classical phosphorylation sites and of β‐arrestin 1 recruitment
Authors: Rasmussen Trine N. , Novak Ivana , Nielsen Søren M.
Published: November 2004

The corticotropin releasing factor receptor 1 (CRFR1) belongs to the superfamily of G‐protein coupled receptors. Though CRF is involved in the aetiology of several stress‐related disorders, including depression and anxiety, details of CRFR1 regulation such as internalization remain uncharacterized. In the present study, agonist‐induced internalization of CRFR1 in HEK293 cells was visualized by confocal microcopy and quantified using the radioligand 125I‐labelled sauvagine. Recruitment of β‐arrestin 1 in response to receptor activation was demonstrated by confocal microscopy. The extent of 125I‐labelled sauvagine stimulated internalization was significantly impaired by sucrose, indicating the involvement of clathrin‐coated pits. No effect on the extent of internalization was observed in the presence of the second messenger dependent kinase inhibitors H‐89 and staurosporine, indicating that cAMP‐dependent protein kinase and protein kinase C are not prerequisites for CRFR1 internalization. Surprisingly, deletion of all putative phosphorylation sites in the C‐terminal tail, as well as a cluster of putative phosporylation sites in the third intracellular loop, did not affect receptor internalization. However, these mutations almost abolished the recruitment of β‐arrestin 1 following receptor activation. In conclusion, we demonstrate that CRFR1 internalization is independent of phosphorylation sites in the C‐terminal tail and third intracellular loop, and the degree of β‐arrestin 1 recruitment.
An extension to the metabolic control theory taking into account correlations between enzyme concentrations
Authors: Lion Sébastien , Gabriel Frédéric , Bost Bruno , Fiévet Julie , Dillmann Christine , De Vienne Dominique
Published: November 2004

The classical metabolic control theory [Kacser, H. & Burns, J.A. (1973) Symp. Soc. Exp. Biol.27, 65–104; Heinrich, R. & Rapoport, T. (1974) Eur. J. Biochem.42, 89–95.] does not take into account experimental evidence for correlations between enzyme concentrations in the cell. We investigated the implications of two causes of linear correlations: competition between enzymes, which is a mere physical adaptation of the cell to the limitation of resources and space, and regulatory correlations, which result from the existence of regulatory networks. These correlations generate redistribution of enzyme concentrations when the concentration of an enzyme varies; this may dramatically alter the flux and metabolite concentration curves. In particular, negative correlations cause the flux to have a maximum value for a defined distribution of enzyme concentrations. Redistribution coefficients of enzyme concentrations allowed us to calculate the ‘combined response coefficient’ that quantifies the response of flux or metabolite concentration to a perturbation of enzyme concentration.
Insights into the reaction mechanism of glycosyl hydrolase family 49
Authors: Akeboshi Hiromi , Tonozuka Takashi , Furukawa Takaaki , Ichikawa Kazuhiro , Aoki Hiroyoshi , Shimonishi Akiko , Nishikawa Atsushi , Sakano Yoshiyuki
Published: November 2004

Aspergillus niger isopullulanase (IPU) is the only pullulan‐hydrolase in glycosyl hydrolase (GH) family 49 and does not hydrolyse dextran at all, while all other GH family 49 enzymes are dextran‐hydrolysing enzymes. To investigate the common catalytic mechanism of GH family 49 enzymes, nine mutants were prepared to replace residues conserved among GH family 49 (four Trp, three Asp and two Glu). Homology modelling of IPU was also carried out based on the structure of Penicillium minioluteum dextranase, and the result showed that Asp353, Glu356, Asp372, Asp373 and Trp402, whose substitutions resulted in the reduction of activity for both pullulan and panose, were predicted to be located in the negatively numbered subsites. Three Asp‐mutated enzymes, D353N, D372N and D373N, lost their activities, indicating that these residues are candidates for the catalytic residues of IPU. The W402F enzyme significantly reduced IPU activity, and the Km value was sixfold higher and the k0 value was 500‐fold lower than those for the wild‐type enzyme, suggesting that Trp402 is a residue participating in subsite −1. Trp31 and Glu273, whose substitutions caused a decrease in the activity for pullulan but not for panose, were predicted to be located in the interface between N‐terminal and β‐helical domains. The substrate preference of the negatively numbered subsites of IPU resembles that of GH family 49 dextranases. These findings suggest that IPU and the GH family 49 dextranases have a similar catalytic mechanism in their negatively numbered subsites in spite of the difference of their substrate specificities.
The Thermoplasma acidophilum Lon protease has a Ser‐Lys dyad active site
Authors: Besche Henrike , Zwickl Peter
Published: November 2004

A gene with significant similarity to bacterial Lon proteases was identified during the sequencing of the genome of the thermoacidophilic archaeon Thermoplasma acidophilum. Protein sequence comparison revealed that Thermoplasma Lon protease (TaLon) is more similar to the LonB proteases restricted to Gram‐positive bacteria than to the widely distributed bacterial LonA. However, the active site residues of the protease and ATPase domain are highly conserved in all Lon proteases. Using site‐directed mutagenesis we show here that TaLon and EcLon, and probably all other Lon proteases, contain a Ser‐Lys dyad active site. The TaLon active site mutants were fully assembled and, similar to TaLon wild‐type, displayed an apparent molar mass of 430 kDa upon gelfiltration. This would be consistent with a hexameric complex and indeed electron micrographs of TaLon revealed ring‐shaped particles, although of unknown symmetry. Comparison of the ATPase activity of Lon wild‐type from Thermoplasma or Escherichia coli with respective protease active site mutants revealed differences in Km and V values. This suggests that in the course of protein degradation by wild‐type Lon the protease domain might influence the activity of the ATPase domain.
Symmetric fluoro‐substituted diol‐based HIV protease inhibitors
Authors: Lindberg Jimmy , Pyring David , Löwgren Seved , Rosenquist Åsa , Zuccarello Guido , Kvarnström Ingemar , Zhang Hong , Vrang Lotta , Classon Björn , Hallberg Anders , Samuelsson Bertil , Unge Torsten
Published: November 2004

HIV‐1 protease is a pivotal enzyme in the later stages of the viral life cycle which is responsible for the processing and maturation of the virus particle into an infectious virion. As such, HIV‐1 protease has become an important target for the treatment of AIDS, and efficient drugs have been developed. However, negative side effects and fast emerging resistance to the current drugs have necessitated the development of novel chemical entities in order to exploit different pharmacokinetic properties as well as new interaction patterns. We have used X‐ray crystallography to decipher the structure–activity relationship of fluoro‐substitution as a strategy to improve the antiviral activity and the protease inhibition of C2‐symmetric diol‐based inhibitors. In total we present six protease–inhibitor complexes at 1.8–2.3 Å resolution, which have been structurally characterized with respect to their antiviral and inhibitory activities, in order to evaluate the effects of different fluoro‐substitutions. These C2‐symmetric inhibitors comprise mono‐ and difluoro‐substituted benzyloxy side groups in P1/P1′ and indanoleamine side groups in P2/P2′. The ortho‐ and meta‐fluorinated P1/P1′‐benzyloxy side groups proved to have the most cytopathogenic effects compared with the nonsubstituted analog and related C2‐symmetric diol‐based inhibitors. The different fluoro‐substitutions are well accommodated in the protease S1/S1′ subsites, as observed by an increase in favorable Van der Waals contacts and surface area buried by the inhibitors. These data will be used in the development of potent inhibitors with different pharmacokinetic profiles towards resistant protease mutants.
Inhibition of l‐arginine transport in platelets by asymmetric dimethylarginine and NG‐monomethyl‐l‐arginine: Effects of arterial hypertension
Authors: Brunini TMC , Moss MB , Siqueira MAS , Meirelles LR , Rozentul AL , Mann GE , Ellory JC , Soares de Moura R , Mendes‐Ribeiro AC
Published: November 2004

1. Nitric oxide (NO) produced by human platelets plays an important role in all stages of platelet activation. l‐Arginine, the precursor for NO synthesis, modulates NO production by platelets. The l‐arginine analogues asymmetric dimethylarginine (ADMA) and NG‐monomethyl‐l‐arginine (l‐NMMA) are endogenous inhibitors of nitric oxide synthase (NOS), involved in the physiopathology of arterial hypertension. The aim of the present study was to investigate the inhibitory effects of endogenous and exogenous l‐arginine analogues on l‐arginine influx in platelets from healthy controls and hypertensive patients.

2. Twelve patients with uncomplicated essential hypertension (stage I) and 15 age‐matched normotensive controls participated in the present study. Platelets were isolated and incubated with l‐[3H]‐arginine and increasing concentrations of l‐arginine analogues (5–2000 µmol/L).

3. The influx of l‐arginine was inhibited in a concentration‐dependent manner by l‐NMMA in platelets from controls (Ki = 42 ± 6 µmol/L) and this inhibitory effect was markedly higher in hypertensive platelets (Ki = 23 ± 4 µmol/L).

4. Similarly, the Ki for ADMA inhibition of l‐arginine transport was significantly more pronounced in platelets from hypertensive patients (Ki = 16 ± 1 µmol/L) compared with controls (Ki = 27 ± 2 µmol/L).

5. In contrast, NG‐nitro‐l‐arginine methyl ester (l‐NAME) was found to be a weak inhibitor of l‐arginine influx in platelets from controls (Ki = 1917 ± 319 µmol/L) and hypertensive patients (Ki = 2279 ± 578 µmol/L). Aminoguanidine, a selective inhibitor of inducible NOS, failed to inhibit l‐arginine transport.

6. Our findings provide the first evidence that ADMA and l‐NMMA markedly inhibit l‐arginine transport in human platelets, an effect that is more pronounced in hypertensive patients. It is possible that endogenous l‐arginine analogues, by inhibiting NO synthesis, are involved in the platelet activation present in hypertension.
Improvement of spatial cognition with dietary docosahexaenoic acid is associated with an increase in Fos expression in rat CA1 hippocampus
Authors: Tanabe Yoko , Hashimoto Michio , Sugioka Kozo , Maruyama Megumi , Fujii Yoshimi , Hagiwara Rika , Hara Toshiko , Hossain Shahdat Md , Shido Osamu
Published: November 2004

1. Twenty 5‐week‐old male Wistar rats were divided into two groups: one group was fed a fish oil‐deficient diet and the other group was fed the same diet supplemented with per orally administered docosahexaenoic acid (DHA) for 12 weeks.

2. Six weeks after the start of the administration of DHA, rats were trained for 6 weeks to acquire a reward at the end of each of four arms of an eight‐arm radial maze. On completion of the radial maze task, the Fos expression in the hippocampus was examined immunohistochemically.

3. Chronic DHA administration significantly reduced the number of reference and working memory errors. The number of Fos‐positive neurons in the CA1 hippocampus significantly increased in DHA‐treated rats compared with control rats, demonstrating a statistically significant negative correlation with the number of reference memory errors.

4. These results suggest that the DHA‐induced improvement in spatial cognition is associated with increased Fos expression in the CA1 hippocampus.
Vascular gap junctions and implications for hypertension
Authors: Rummery Nicole M , Hill Caryl E
Published: November 2004

1. Four connexin (Cx) molecules, namely Cx37, Cx40, Cx43 and Cx45, are expressed in the gap junctions that exist within and between the cellular layers of arteries.

2. Endothelial cells are well coupled by large gap junctions expressing Cx37, Cx40 and, to a lesser extent, Cx43, whose expression may be more subject to regulation by physical factors.

3. Smooth muscle cells are more heterogeneously coupled by gap junctions that are small and rare. The identity of the Cx expressed in the media may vary among different arteries.

4. Myoendothelial gap junctions are small and more common in resistance arteries with fewer layers of smooth muscle cells. Given the small size of these gap junctions and the rapid turnover rate of Cxs, homocellular coupling in the media and heterocellular coupling between the cell layers may be subject to more dynamic control than coupling in the endothelium.

5. Vascular gap junctions have been implicated in a number of vasomotor responses that may regulate vascular tone and blood pressure. These include the mechanism of action of the vasodilator, endothelium‐derived hyperpolarizing factor (EDHF), the myogenic constriction to intramural pressure increase, the spontaneous or agonist‐induced vasomotion of arteries and arterioles and the spreading vasodilation and constriction observed in microcirculatory networks.

6. Few data are available on Cx expression in the media of resistance arteries during hypertension. Changes in the expression of Cx43 described in the media of the aorta of hypertensive rats vary with the hypertensive model studied and are likely to represent adaptations to structural changes in the vascular wall.

7. In contrast, in the endothelium of the caudal and mesenteric arteries of spontaneously hypertensive rats, expression of Cxs is significantly decreased compared with arteries from normotensive rats and this decrease is reversed by inhibitors of the renin–angiotensin system.

8. During hypertension, the activity of EDHF is decreased in the mesenteric artery, but this occurs much later than the initial increase in blood pressure and the decrease in endothelial Cxs, suggesting that changes in EDHF may not be causally related to hypertension or to the changes in endothelial Cxs.

9. Upregulation of the myogenic response and the incidence of vasomotion has been reported in hypertension. Little is currently known of the effects of hypertension on spreading vasomotor responses.

10. Deletion of specific Cxs in genetically modified mice is complicated by neonatal lethality or coordinate regulation and compensatory changes in the remaining Cxs. Nevertheless, mice in which Cx40 has been deleted are hypertensive and spreading vasodilatory responses are significantly impaired.

11. Determination of a role for specific Cxs in the control of blood pressure must await the development of animals in which Cx expression can be modulated in a more complex temporal and tissue‐specific manner.
Role of endogenous macrophage inflammatory protein‐2 in regulating fever induced by bacterial endotoxin in normal and immunosuppressed rats
Authors: Miñano Francisco J , Tavares Eva , Maldonado Rosario
Published: November 2004

1. During myelosuppressive chemotherapy, Gram‐negative bacterial infection with consequent exposure to lipopolysaccharide (LPS) is one of the most important causes of persistent fever.

2. The classical model of the pathogenesis of fever suggests that pro‐inflammatory cytokines, produced by leucocytes in the bloodstream in response to exogenous pyrogens such as bacterial LPS, represent the distal mediators of the febrile response. Neutrophils are the first effectors cells and the most prominent leucocyte population involved in acute bacterial infection.

3. Macrophage inflammatory protein (MIP)‐2 plays a crucial role in influencing early cell trafficking and neutrophil activation during pathophysiological processes and serves the same chemotactic function as human interleukin‐8.

4. In the present study, we investigated the role of MIP‐2 in the development of a febrile response induced by LPS in immunocompetent and leukopenic rats.

5. Intraperitoneal injection of LPS in leukopenic rats elicited a biphasic febrile response of rapid onset, the magnitude and duration of which were significantly greater than in immunocompetent animals. The febrile responses to LPS were accompanied by a pronounced induction of serum MIP‐2 levels at 1, 2 and 4 h compared with their respective controls.

6. In both normal and leukopenic rats, neutralization of endogenous MIP‐2 bioactivity by systemic administration of antirat MIP‐2 antibody caused a significant attenuation of the early phase of LPS fever. However, in contrast with normal rats, the second phase of fever was unimpaired by anti‐MIP‐2 in leukopenic rats. These findings suggest that circulating MIP‐2 is involved in the generation of the early phase of LPS fever that contributes to the maintenance of the later phase of fever in immunocompetent, but not leukopenic, rats.

7. Our data support a regulatory role for endogenous MIP‐2 in initiating the fever responses to LPS. Furthermore, these results provide evidence that different cellular and humoral mechanisms are implicated in the development of a febrile response triggered by Gram‐negative bacterial infections in leukopenic hosts.
Sulphur and skin: from Satan to Saddam!
Authors: Leslie K S , Millington G W M , Levell N J
Published: November 2004

Since the dawn of time, Beelzebub has been showering fire and brimstone (sulphur) on tortured souls, but the cutaneous effects of this have been poorly described.

Sulphur has also been used for centuries as a treatment for many skin conditions, such as fungal infections, scabies, psoriasis, eczema and acne. It has also been used extensively in cosmetic preparations and by cosmetic dermatologists treating conditions such as seborrhoeic eczema. Many natural bathing spas have high levels of sulphur; such balneology has been advocated by medical and cosmetic dermatologists as an effective treatment for cutaneous disorders for more than 500 years. Sulphur was often the active agent in many of the so‐called ‘patent medicines’ that became popular in the mid‐nineteenth century.

Time has not withered medical practitioners’ enthusiasm for sulphur. There are various reports in the medical literature of its current use. However sulphur treatment is not without its risks; a sulphur spring dermatitis has been described from a spa bath in Taiwan. With the satanic threat of bio‐terrorism, some dermatologists may be treating the effects of contact with sulphur mustard all too soon.
Smoking can be good for you
Authors: Wolf R , Orion E , Matz H , Maitra S , Rowland‐Payne C
Published: November 2004

Smoking is without doubt one of the greatest causes of avoidable illness and death in the modern world. Most well known is the relationship between smoking and numerous cancers, cerebrovascular and cardiovascular disease.

Smoking and most especially nicotine, are, however, sometimes beneficial in certain diseases, including Parkinson's, Alzheimer's, allergic alveolitis, nausea and vomiting of pregnancy, pre‐eclampsia, fibroids, carcinoma of body of uterus, ulcerative colitis, pyoderma gangrenosum, aphthous stomatitis and ulceration, pemphigus, herpes simplex and acne.

In the immensely justifiable enthusiasm to discredit this dangerous activity, the mechanisms behind these beneficial effects tend to have been un‐discussed or ignored.

It is the aim of this paper to spur interest in the reasons for these effects. If the mechanisms are elucidated, therapeutic advances may be possible.
Patapius spinosus: First record of Leptopodidae (Heteroptera) from Japan
Authors: YAMAZAKI Kazuo , SUGIURA Shinji
Published: November 2004

Patapius spinosus, a remarkable leptopodid bug whose body is covered with spines, was collected for the first time in Japan. This species was found in the supralittoral zone of a sandy beach in Osaka Prefecture, central Japan, in autumn 2002 and in spring 2004. Patapius spinosus is known to be distributed in the Mediterranean and North African regions, and has been introduced into North America and Chile. Its occurrence in Japan could signify either an eastern limit of its native distribution or an exotic origin.
Faunal make‐up, host range and infestation rate of weevils and tephritid flies associated with flower heads of the thistle Cirsium (Cardueae: Astaraceae) in Japan
Authors: NAKAMURA Akinori , NAKAMURA Koji
Published: November 2004

From 1988 to 1998, we collected flower heads of 39 thistle taxa (35 taxa of Cirsium, one species each of Breea, Synurus, Saussurea and Arctium; Cardueae; Astaraceae) in Japan, mainly from Hokuriku and other parts of central Honshu, and kept them in the laboratory to breed weevils and tephritid flies, the core fauna. We report the faunal make‐up, host plants, geographic distribution and the attack levels of the insects. Results indicated that (i) three Larinus species (Curculionidae) and three species of tephritid flies (Tephritis, Urophora and Xyphosia) comprised the core fauna; (ii) two insect species belonging to the same taxonomic group (either Curculionidae (Larinus) or Tephritidae) tended to use different host plant species; (iii) two sympatric Larinus species (L. latissimus and L. meleagris) segregated the host plants seasonally in central Honshu (Cirsium blooming in spring and autumn, respectively); and (iv) two tephritid fly species, Xyphosia punctigera and Urophora sachalinensis, segregated geographically (the former on the Japan Sea side and the latter on the Pacific Ocean side). In comparison with their European counterparts, the weevils and tephritids of the Japanese Cirsium are characterized by a lower species richness and a lower degree of specialization in usage of the thistle flower heads, with gall‐formers being distinctly under‐represented, and callus tissue‐feeders being absent. This reflects the fact that Japanese thistles are so closely related that hybridization frequently occurs, and also that the thistles have had a short history of interaction with the insects since the thistles’ arrival in Japan.
Cryptically dimorphic caste differences in a Neotropical, swarm‐founding paper wasp genus, Parachartergus (Hymenoptera: Vespidae)
Authors: SAITO Fuki , MURAKAMI Takahiro , KOJIMA Jun‐ichi
Published: November 2004

Morphological differences in body shape between females of different reproductive conditions (in terms of insemination and ovarian development) were examined in two species of the Neotropical polistine genus Parachartergus: P. smithii and P. fraternus. The present study shows, for the first time, that non‐size‐based morphological divergence between queens and workers occurs in Parachartergus, an epiponine genus once believed to have little or no morphological caste differences. In the P. smithii colony examined, queens were significantly larger than workers in five of the eight body parts measured (head width, eye width, genal width, mesosomal length, wing length, first metasomal tergum width, and width and length of the second tergum), but the mean values of wing length and first and second tergum widths were not significantly different between them. The queen : worker size ratios tended to be greater anteriorly and smaller posteriorly, although the size ratio was greatest in second tergum length. Analysis of covariance (ancova) with mesosomal length as covariate showed that queens had proportionally wider heads and narrower first terga than did workers. In the P. fraternus colony, size differences between queens and workers were not significant, and there was little or no difference in shape, but queens had significantly proportionally wider first terga than did workers.
Factors Associated With Urea Reduction Ratio in Acute Renal Failure
Authors: Liangos Orfeas , Rao Madhumati , Ruthazer Robin , Balakrishnan Vaidyanathapuram S. , Modi Gopesh , Pereira Brian J.G. , Jaber Bertrand L.
Published: November 2004

Abstract:  Prescription and delivery of hemodialysis (HD) in acute renal failure (ARF) may be affected by patient‐related factors such as hemodynamic instability, catabolism, variable extracellular fluid volume, and coagulation disturbances. This study was undertaken in a cohort of patients with ARF requiring HD, to quantify patient‐ and dialysis‐related variables that influence dialysis delivery. The urea reduction ratio (URR) was calculated for each HD session. Patient‐related variables included age, gender, weight, mean arterial pressure, and Acute Physiological and Chronic Health Evaluation (APACHE) II and Multiple Organ Failure (MOF) scores. Dialysis‐related variables were dialyzer characteristics (membrane type, surface area, KoA, and KUF), blood flow rate (Qb), session length, anticoagulant use, vascular access, and ultrafiltration volume. The analysis of factors associated with URR was performed using mixed linear statistical models. The cohort consisted of 81 adult patients with ARF who underwent 419 consecutive dialysis sessions. Mean (± SD) age was 60 ± 18 years; 57% were male. At dialysis initiation, APACHE II score was 23 ± 8 and MOF score 2 ± 1. The number of HD treatments averaged 5.5 ± 6.1/patient and 0.8 ± 0.2/patient/day, mean URR was 54 ± 15%, and session length 3.2 ± 1.1 h; 58% used a femoral venous catheter, and 92% polysulfone dialyzers. Among patient‐related variables, the only independent predictor of delivered dose of dialysis, as measured by URR was the predialysis weight (P < 0.01). Among the dialysis‐related variables, treatment time (P < 0.01), dialyzer surface area (P < 0.01), dialyzer KUF (P = 0.04), blood flow rate (P < 0.01), and the use of a femoral venous catheter (P < 0.01) were also independently associated with URR. An interaction between vascular access site and blood flow rate was also found to be significant (P < 0.01). This study underscores the importance of the dialysis prescription parameters and vascular access site in influencing the dialysis dose in critically ill patients, and argues against the importance of patient‐related characteristics such as disease  severity.
Scaling and root planing, systemic metronidazole and professional plaque removal in the treatment of chronic periodontitis in a Brazilian population
Authors: Carvalho L. H. , D'Avila G. B. , Leão A. , Haffajee A. D. , Socransky S. S. , Feres M.
Published: November 2004

Objective: The current investigation evaluated the clinical effects of scaling and root planing (SRP) alone or in combination with systemic metronidazole and/or repeated professional removal of supragingival plaque in subjects with chronic periodontitis.

Methods: Fourty‐four adult subjects (mean age: 45±6 years) with periodontitis were randomly assigned to four treatment groups; a control (C, n=10) that received SRP and placebo and three test groups treated as follows: Test 1 (T1) (n=12) received SRP and metronidazole (400 mg t.i.d., M) for 10 days; Test 2 (T2) (n=12) received SRP, weekly professional supragingival plaque removal for three months (professional cleaning (PC)) and placebo; and Test 3 (T3) (n=10) received SRP, M and PC. Pocket depth (PD), attachment level (AL), bleeding on probing (BOP) and presence of visible plaque and suppuration were measured at six sites per tooth at baseline and at 90 days post‐therapy. Significance of differences over time was determined using the Wilcoxon test, and among groups using ancova.

Results: A reduction in full‐mouth mean clinical parameters was observed at 90 days after all therapies. Sites with baseline PD<4 mm showed an increase in mean PD in the control group and in mean AL in all treatment groups. Sites with baseline PD of 4–6 mm in subjects who received PC as part of therapy (T2, T3) showed a marked reduction in PD, AL and in the % of sites with BOP. Subjects who received metronidazole (T1 and T3) showed the best clinical response at sites with an initial PD of >6 mm. The major clinical benefit occurred when the combination of SRP, M and PC was used. Group T3 showed the least attachment loss in initially shallow pockets. This group also exhibited the greatest reduction in the % of sites with BOP and suppuration as well as in mean PD and AL at sites with baseline PD>4 mm.

Conclusion: The data suggest a significant clinical benefit in combining SRP, systemic metronidazole and weekly professional supragingival plaque removal for the treatment of chronic periodontitis.
Quantitative real‐time polymerase chain reaction based on single copy gene sequence for detection of periodontal pathogens
Authors: Morillo Juan Manuel , Lau Laura , Sanz Mariano , Herrera David , Martín Conchita , Silva Augusto
Published: November 2004

Objective: To develop a method for quantification of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Tannerella forsythensis (Tf) from subgingival plaque samples based on TaqMan real‐time polymerase chain reaction (PCR) technology.

Material and Methods: Bacterial cells from these species were obtained after culturing reference strains and were counted microscopically. Cellular suspensions in Tris‐EDTA buffer were used for DNA extraction after boiling for 20 min. Primers for PCR were selected from sequences of the LktC (Aa), Arg‐gingipain (Pg) and BspA antigen (Tf) genes in order to yield amplicons below 100 bp. TaqMan‐based real‐time PCR was adjusted to quantify each species separately. Cycle threshold (CT) values were calculated for each species according to the initial number of copies. A reliability analysis was carried out using intra‐class correlation coefficients (ICCs) with a two‐way random effects model.

Results: A high sensitivity and specificity was obtained for the detection of the three bacterial species. The TaqMan real‐time PCR technology yielded a good repeatability in the obtained cycle threshold (CT) values for each initial number of copies, demonstrating coefficients of variation below 5% for each bacteria. The reproducibility of the technique was also demonstrated by the high ICCs (>0.98; p<0.00001) obtained for each bacteria with and without the addition of subgingival plaque.

Conclusion: A novel diagnostic method based on TaqMan real‐time PCR was developed for the quantification of Aa, Pg and Tf. It has demonstrated good sensitivity and repeatability on pure cultures. Its diagnostic utility should be demonstrated in subgingival plaque samples.
Methods of detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in periodontal microbiology, with special emphasis on advanced molecular techniques: a review
Authors: Sanz Mariano , Lau Laura , Herrera David , Morillo Juan Manuel , Silva Augusto
Published: November 2004

Background: Certain specific bacterial species from the subgingival biofilm have demonstrated aetiological relevance in the initiation and progression of periodontitis. Among all the bacteria studied, three have shown the highest association with destructive periodontal diseases: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Tannerella forsythensis (Tf). Therefore, the relevance of having accurate microbiological diagnostic techniques for their identification and quantification is clearly justified.

Aim: To evaluate critically all scientific information on the currently available microbial diagnostic techniques aimed for the identification and quantification of Aa, Pg and Tf.

Summary: Bacterial culturing has been the reference diagnostic technique for many years and, in fact, most of our current knowledge on periodontal microbiology derives from cultural data. However, the advent of new microbial diagnostics, mostly based on immune and molecular technologies, has not only highlighted some of the shortcomings of cultural techniques but has also allowed their introduction as easy and available adjunct diagnostic tools to be used in clinical research and practice. These technologies, mostly polymerase chain reaction (PCR), represent a field of continuous development; however, we still lack the ideal diagnostic to study the subgingival microflora. Qualitative PCR is still hampered by the limited information provided. Quantitative PCR is still in development; however, the promising early results reported are still hampered by the high cost and the equipment necessary for the processing.

Conclusion: Quantitative PCR technology may have a major role in the near future as an adjunctive diagnostic tool in both epidemiological and clinical studies in periodontology. However, culture techniques still hold some inherent capabilities, which makes this diagnostic tool the current reference standard in periodontal microbiology.
Alterations of gene expression in human neutrophils induced by smoking cessation
Authors: Morozumi Toshiya , Kubota Takehiko , Sugita Noriko , Itagaki Manami , Yoshie Hiromasa
Published: November 2004

Objective: The purpose of the present study was to investigate the effect of smoking cessation on the peripheral neutrophil mRNA expression levels for inflammatory cytokines, chemokine, growth factor and matrix metalloproteinase (MMP).

Material and Methods: Sixteen male smokers (aged 22–39 [25.3±4.0] years), with no clinical signs of periodontal and systemic diseases, were recruited. The experiment was performed before (baseline) and at 1, 4 and 8 weeks after smoking cessation. The status of smoking and smoking cessation was verified by exhaled carbon monoxide (CO) concentration and serum cotinine concentration. Neutrophils were isolated from each subjects' peripheral blood, then the cell was stimulated with N‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP). The mRNA expression levels for interleukin (IL)‐1β, IL‐8, tumor necrosis factor (TNF)‐α, vascular endothelial growth factor (VEGF) and MMP‐8 were analyzed by semiquantitative reverse transcription‐polymerase chain reactions. The same experiment was performed on 11 non‐smoking controls (four female and seven male), aged 23–27 (24.4±1.2) years.

Results: Eleven of 16 smokers successfully completed smoking cessation for 8 weeks. At 1 day after smoking cessation, there was a statistically significantly lower CO concentration than at baseline (p<0.01). Also, cotinine concentration markedly decreased at the second measurement, which was taken at 1 week. All of the analyzed mRNA expression levels of neutrophils from smokers were statistically significantly lower than that in non‐smokers (p<0.01: IL‐1β, IL‐8, VEGF; p<0.05: TNF‐α, MMP‐8). The MMP‐8 mRNA levels were statistically significantly increased at 8 weeks after smoking cessation compared with the baseline (p<0.05). Although the other mRNA expression levels were also elevated gradually from the baseline, they did not reach the statistically significant levels at 8 weeks after smoking cessation.

Conclusion: The results showed that the neutrophil transcript levels in smokers were generally lower than those in non‐smokers, which could be related to an impairment of neutrophils by smoking effects. The significant increase of MMP‐8 mRNA levels were associated with the effects of smoking cessation, while recovery of the other mRNA levels seemed to require a bit longer period beyond 8 weeks after smoking cessation.
Dental nomograms for benchmarking based on the study of health in Pomerania data set
Authors: Schwahn C. , Meisel P. , Biffar R. , König J. , John U. , Kocher T.
Published: November 2004

Aim: Benchmarking is a means of setting goals or targets. On an oral health level, it denotes retaining more teeth and/or improving the quality of life. The goal of this pilot investigation was to assess whether the data generated by a population‐based study (SHIP 0) can be used as a benchmark data set to characterize different practice profiles.

Material and Methods: The data collected in the population‐based study SHIP (n=4310) in eastern Germany were used to generate nomograms of tooth loss, attachment loss, and probing depth. The nomograms included twelve 5‐year age strata (20–79 years) presented as quartiles, and additional percentiles of the dental parameters for each age group. Cross‐sectional data from a conventional dental office (n=186) and from a periodontology unit (n=130, Greifswald) in the study region as well as longitudinal data set of a another periodontology unit (n=135, Kiel) were utilized in order to verify whether the given practice profile was accurately reflected by the nomogram.

Results: In terms of tooth loss, the data from the conventional dental office agree with the median from the nomogram. For attachment loss and probing depth, some age groups yielded slight but not uniform deviations from the median. Cross‐sectional data from the periodontology unit Greifswald showed attachment loss higher than the median in younger but not in older age groups. The probing depth was uniformly less than the median and tended toward the 25th percentile with increasing age. The longitudinal data of the Unit of Periodontology in Kiel showed a pronounced trend towards higher percentiles of residual teeth, meaning that the patients retained more teeth.

Conclusion: The profile of the Pomeranian dental office does not deviate noticeably from the population‐based nomograms. The higher attachment loss of the Unit of Periodontology in Greifswald in younger age strata clearly reflects their selection because of periodontal disease; the combination of higher attachment loss and decreased probing depth may reflect the success of the treatment. The tendency of attachment loss towards the median with increasing age may indicate that the Unit of Periodontology in Greifswald does not fulfill its function as a special care unit in the older subjects. The longitudinal data set of the Unit of Periodontology in Kiel impressively reflects the potential of population‐based data sets as a means for benchmarking. Thus, nomograms can help to determine the practice profile, potentially yielding benefits for the dentist, health insurance company, or – as in the case of the special care unit – public health research.
Effect of dissociating cytosolic calcium and metabolic rate on intracellular PO2 kinetics in single frog myocytes
Authors: Kindig Casey A. , Stary Creed M. , Hogan Michael C.
Published: November 2004

The purpose of this investigation was to utilize 2,3‐butanedione monoxime (BDM; an inhibitor of contractile activation) to dissociate cytosolic [Ca2+] ([Ca2+]c) from the putative respiratory regulators that arise from muscle contraction‐induced ATP utilization in order to determine the relative contribution of [Ca2+]c on intracellular PO2 (PiO2) kinetics during the transition from rest to contractions in single skeletal myocytes isolated from Xenopus laevis lumbrical muscle. Myocytes were subjected to electrically induced isometric tetanic contractions (0.25 Hz; 2‐min bouts) while peak tension and either [Ca2+]c (n= 7; ratiometric fluorescence microscopy) or PiO2 (n= 7; phosphorescence microscopy) was measured continuously. Cells were studied under both control and 3 mm BDM conditions in randomized order. Initial (control, 100 ± 0%; BDM, 72.6 ± 4.6%), midpoint (control, 86.7 ± 1.8%; BDM, 61.6 ± 4.1%) and end (control, 85.0 ± 2.8%; BDM, 57.5 ± 5.0%) peak tensions (normalized to initial control values) were significantly reduced (P < 0.05) with BDM compared with control (n= 14). Despite the reduced peak tension, peak [Ca2+]c was not altered (P > 0.05) between control and BDM trials. Thus, the peak tension‐to‐peak [Ca2+]c ratio was reduced with BDM compared with control. The absolute fall in PiO2 with contractions, which is proportional to the rise in , was significantly reduced with BDM (13.2 ± 1.3 mmHg) compared with control (22.0 ± 2.0 mmHg). However, PiO2 onset kinetics (i.e. mean response time (MRT)) was not altered between BDM (66.8 ± 8.0 s) and control (64.9 ± 6.3 s) trials. Therefore, the initial rate of change (defined as the fall in PiO2/MRT) was significantly slower in BDM fibres compared with control. These data demonstrate in these isolated single skeletal muscle fibres that unchanged peak [Ca2+]c in the face of reduced metabolic feedback from the contractile sites evoked with BDM did not alter PiO2 onset kinetics in isolated single frog myocytes, suggesting that metabolic signals arising from the contractile sites play a more substantial role than [Ca2+]c in the signalling pathway to oxidative phosphorylation during the transition from rest to repeated tetanic contractions.
Structure of cortical microcircuit theory
Authors: Földy Csaba , Dyhrfjeld‐Johnsen Jonas , Soltesz Ivan
Published: November 2004

Recent experimental and theoretical investigations have made considerable advances in three major areas relating to the structural basis of quantitative cortical microcircuit theory. The first concerns the nature of the cellular units, encompassing the increasingly precise identification and progressively more complete listing of the individual cellular species that constitute the various cortical networks. The second element addresses the problem of heterogeneity, including the demonstration of the importance of cell to cell variability within defined interneuronal populations and the application of the Shannon‐Wiener diversity index for the quantitative assessment of the number and relative abundance of interneuronal species. The third component relates to the discovery of basic topological principles underlying the circuit wiring, revealing a surprising order in the architectural design of networks. These new advances deepen our understanding of the computational principles embedded in cortical microcircuits, and they also provide novel opportunities for building realistic models of mammalian cortical microcircuits.
CONSTRUCTING LANGUAGE INSTANCES BASED ON PARTIAL INFORMATION
Authors: SANCHIS LAURA A.
Published: November 2004

We investigate the problem of when it is possible to efficiently construct an instance of a given language in P or NP, based on partial information provided about the desired instance. We model this problem by specifying a prefix and a length for the string to be produced. Our results suggest that it may be harder to find efficient constructors for languages in NP if more information is provided about the desired element (assuming that P is not equal to NP). Specifically, for large enough prefix functions, polynomial-time prefix-based constructors cannot exist for all languages in NP unless P=NP. For smaller prefix functions, the existence of such constructors cannot be determined using techniques that relativize, under the assumption that P≠NP. We also show through relativizations and other results, what appears to be a pattern of increasing difficulty for efficient construction as the prefix function increases within this range. For languages in P, however, the difficulty of construction first increases and then appears to decrease as the size of the prefix is increased. We also relate prefix-based construction to that based on more general parameter functions for the strings. In addition, we examine the related ranking problem in the same context, and prove some results about the existence of prefix-based rankers for languages in P and NP.
SUPERVISED LEARNING ON LARGE REDUNDANT TRAINING SETS
Authors: MØLLER MARTIN
Published: November 2004

Efficient supervised learning on large redundant training sets requires algorithms where the amount of computation involved in preparing each weight update is independent of the training set size. Off-line algorithms like the standard conjugate gradient algorithms do not have this property while on-line algorithms like the stochastic backpropagation algorithm do. A new algorithm combining the good properties of off-line and on-line algorithms is introduced.
THERMODYNAMIC TRANSITIONS IN NETWORKS FOR LETTER DISTINCTION
Authors: ROMEO AUGUST
Published: November 2004

Stochastic learning for a kind of feature detectors is studied. The technique is applied to multilayer neural networks intended for T-C discrimination. After evaluating the generalization error function, the training and generalization curves are found by Monte Carlo simulations. Different phase transitions take place and the overall behaviour agrees with previous discussions concerning designs of the same type.
DIGITAL NEURAL NETWORKS FOR HIGH-SPEED DIVISIONS AND ROOT EXTRACTIONS
Authors: DEVILLE YANNICK
Published: November 2004

The instruction set of digital integer-valued VLSIs implementing neural networks is typically restricted to weighted sums, threshold activation functions and weight assignments. However, neural networks also need divisions (for data normalizations) and root extractions (for distance or vector norm computations). This paper presents neural networks which perform the latter operations by using only the above basic instructions. These networks thus provide "macros" to the overall network which calls them. This yields a homogeneous environment. Moreover, a "virtual base" is introduced to exploit the available parallelism. It is freely chosen so as to achieve the desired trade-off between the speed and complexity of the proposed networks (with a minimum of only two neurons). This high-speed capability also makes these structures attractive independently from neural applications.
WEIGHT CONFIGURATIONS OF TRAINED PERCEPTRONS
Authors: TOH H. S.
Published: November 2004

We strive to predict the function mapping and rules performed by a trained perceptron from studying the weights. We derive a few properties of the trained weights and show how the perceptron's representation of knowledge, rules and functions depend on these properties. Two types of perceptrons are studied — one case with continuous inputs and one hidden layer, the other a simple binary classifier with boolean inputs and no hidden units.
DYNAMICS OF ANTAGONISTIC NEURAL PROCESSING ELEMENTS
Authors: KNOPF GEORGE K. , GUPTA MADAN M.
Published: November 2004

Two coupled nonlinear first-order systems whose dynamic behavior reflects the neural states exhibited by a spatially localized population of excitatory and inhibitory nerve cells are described. The dynamics of each constituent neural subpopulation represents a fundamental neural information processing element (PE) of a complex neural system. Phase plane analysis is used in this paper to show how such antagonistic positive acting (excitatory) and negative acting (inhibitory) PEs can generate diverse steady-state and temporal phenomena when the nonlinear system parameters of the PEs are altered. By modifying a selected set of parameters, it is possible to program the positive and negative PEs to exhibit various dynamic attributes such as multiple stable states, transient response behavior and limit-cycle oscillations. These dynamic attributes may be used to perform a variety of useful computational tasks in signal processing and vision systems such as short-term memory (STM), temporal filtering (TF) and pulse frequency modulation (PFM). Computer simulations are presented throughout this paper in order to illustrate these dynamic attributes.