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Intact Controls (intact + control)

Distribution by Scientific Domains

Medical Sciences	60%
Life Sciences	40%

Selected Abstracts

Increased mite parasitism as a cost of testosterone in male striped plateau lizards Sceloporus virgatus

FUNCTIONAL ECOLOGY, Issue 2 2007
ROBERT M. COX
Summary 1Testosterone (T) co-ordinates the seasonal and sex-specific expression of numerous physiological, behavioural and morphological traits that contribute to male reproductive success. However, increased susceptibility to parasitism has been proposed as a potential cost of elevated plasma T. 2During the spring breeding season, male striped plateau lizards Sceloporus virgatus harbour significantly more ectoparasitic mite larvae (Acari: Trombiculidae) than females. Plasma T levels are also elevated in males at this time, suggesting that sex differences in mite parasitism may be driven by underlying sex differences in circulating T. 3We tested this hypothesis experimentally by manipulating plasma T levels of yearling males via surgical castration and exogenous T implants. Upon recapture of free-living animals, we found significantly fewer mites on castrated males relative to either intact controls or castrated males that received T implants. 4After removing variance attributable to treatment effects, we observed (1) a positive correlation between residual measures of plasma T and mite load, and (2) a negative correlation between residual measures of mite load and growth rate. These correlations suggest a growth cost associated with mite parasitism. 5Previous studies have shown that exogenous T increases parasitism, but ours is one of the few to show that castration also reduces parasitism. This result, coupled with the fact that our induced plasma T levels remain within physiological limits, makes this one of the clearest demonstrations of a functional relationship between T and parasitism in any free-living vertebrate. [source]

Interleukin-1 gene polymorphism and periodontal status

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 5 2001
A case-control study
Abstract Objectives: This case-control study examined polymorphisms at the interleukin-1 gene in relation to periodontal status, subgingival bacteria and systemic antibodies to periodontal microbiota. Methods: 132 periodontitis patients were age- and gender-matched with 73 periodontally intact controls. Full-mouth clinical assessments of the periodontal tissues were performed. Subgingival plaque samples (2440 in total) were analyzed by genomic DNA probes, and serum IgG antibodies to periodontal microbiota were assessed by an immunoassay. Polymorphisms in the IL-1A gene at position +4845 and the IL-1B gene at position +3953 were studied by PCR. A composite positive genotype was defined as at least one rare (#2) allele present at each locus. Results: No skewed distribution of the composite genotype was observed between cases and controls (45.2% vs 41.7%). In cases, both the composite genotype and the number of #2 alleles were positively correlated with the severity of attachment loss. No relationship between genotype and subgingival microbial profiles was observed. Genotype positive patients revealed both overall lower serum antibody levels and specific titers against selected bacteria. Conclusions: The composite genotype failed to distinguish between periodontitis patients and controls but correlated in patients with the severity of the disease and the antibody responses to periodontal microbiota. Zusammenfassung Grundlagen: Diese Fall-kontrollierte Studie prüfte die Polymorphismen am Interleukin-1 Gen in Beziehung zum parodontalen Status, subgingivalen Bakterien und systemischen Antikörpern zu parodontalen Mikroorganismen. Methoden: 132 Parodontitis-Patienten wurden nach Alter und Geschlecht mit 73 parodontal gesunden Kontrollen gemischt. Eine vollständige klinische Überprüfung des parodontalen Gewebes wurde durchgeführt. Subgingivale Plaqueproben (insgesamt 2440) wurden mit Genom DNA Testen analysiert, und die Serum IgG Antikörper zu parodontalen Bakterien wurden mit einem Immunoassay bestimmt. Die Polymorphismen am IL-1A Gen an den Stellen +4845 und am IL-1B Gen an der Positon +3953 wurden mittels PCR überprüft. Ein zusammengefaßter positiver Genotyp wurde so definiert, daß mindestens ein seltenes Allel (#2) an jeder Position vorhanden war. Ergebnisse: Es wurde keine schiefe Verteilung der zusammengefaßten Genotypen zwischen den Probanden und den Kontrollen (45.2% versus 41.7%) beobachtet. Bei den Probanden waren sowohl der zusammengefaßte Genotyp als auch die Anzahl der #2 Allele positiv mit dem Ausmaß des Stützgewebeverlustes korreliert. Zwischen den Genotypen und den subgingivalen Bakterienprofilen wurden keine Beziehungen gefunden. Genotyp positive Patienten zeigten sowohl allgemein niedrigere Serumantikörperlevel als auch spezifischen Titer gegen die selektierten Bakterien. Zusammenfassung: Der zusammengefaßte Genotyp untereschied sich nicht zwischen den Parodontitis-Patienten und den Kontrollen, aber korrelierte bei den Patienten mit der Schwere der Erkrankung und der Antikörperantwort auf parodontalen Bakterien. Résumé Cette étude a examiné les polymorphismes du gène Interleukine-1 (IL-1) en relation avec l'état parodontal, les bactéries sous-gingivales et les anticorps systémiques aux bactéries parodontales. 132 patients avec parodontite d'âge et de sexe similaires aux 73 contrôles sans problèmes parodontaux ont été recrutés. Les analyses clinique des tissus parodontaux de toute la bouche ont été effectuées. Des échantillons de plaque dentaire sous-gingivale (2220 au total) ont été analysés par des sondes ADN génomiques et des anticorps IgG sériques aux bactéries parodontales ont été analysés par immuno-essais. Les polymorphismes de IL-1A à la position +4845 et de IL-1B à la position +3953 ont étéétudiés par une réaction de la chaîne polymérase (PCR). Un génotype composite positif était défini comme un rare (#2) allèle présent à chaque endroit. Aucune répartition spéciale du génotype composite n'a été observée entre les cas et les contrôles (45.2% versus 42%). Chez les personnes présentant des cas tant le génotype composite que le nombre d'allèle #2 étaient en relation positive avec la sévérité de la perte d'attache. Aucune relation entre le génotype et les profils microbient sous-gingivaux n'a été mise en évidence. Les patients positifs aux génotypes possédaient des niveaux d'anticorps sériques et des titres spécifiques inférieurs contre des bactéries sélectionnées. Le génotype composite ne permet pas la distinction entre les patients avec parodontite et les contrôles, mais est en corrélation chez les patients avec la sévérité de la maladie et les résponses de l'anticorps à la flore parodontale. [source]

Tissue response to polyglycolide, polydioxanone, polylevolactide, and metallic pins in cancellous bone: An experimental study on rabbits

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2006
Harri Pihlajamäki
Abstract The purpose of this study was to investigate, qualitatively and histoquantitatively, the tissue response of rabbit femur cancellous bone to polyglycolide (PGA), polydioxanone (PDS), polylevolactide (PLLA), and stainless steel pins under identical conditions. Eighty knees in 50 rabbits were operated on by inserting bioabsorbable pins (PGA, PDS, or PLLA) together with metallic Kirschner wire in 60, and two metallic Kirschner wires alone in 20 knees, while 20 knees served as intact controls. Follow-up times were 3, 6, 12, 24, and 52 weeks. Cancellous bone tissue response to implants was studied using histological, histomorphometrical, microradiographical, and oxytetracycline fluorescence methods. Residual fragments of PGA and PDS were seen at 24 weeks. Complete degradation of these polymers had taken place before 52 weeks. No signs of degradation of the PLLA pins were observed within the entire follow-up period. The osteoid formation surfaces at tissue implant-interface were statistically larger in all test groups as compared to intact controls. The number of macrophages at tissue implant-interfaces increased in all bioabsorbable implant specimens until 6 weeks, and with PGA until 12 weeks. No differences in the osseous response emerged when comparing groups of bioabsorbable implants with each other or with stainless steel group. Bioabsorbable pins and metallic Kirschner wires evoked an osteoconductive response in the cancellous bone surrounding implant, but the response intensity between implants displayed no differences. This suggests a simple, nonspecific walling-off new-bone front type of response. Consequently, the polymers possessed no specific osteostimulatory or osteoinhibitory properties. Within the follow-up, no significant differences in biocompatibility between the implants appeared, and no frank inflammatory foreign-body reactions occurred. The small-volume pins obviously did not exceed the local tissue tolerance and clearing capacity of the bone. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1597,1606, 2006 [source]

Investigating mechanical behaviour at a core,sheath interface in peripheral nerve

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 4 2004
Rachel L. Tillett
Abstract As peripheral nerves bend and stretch, internal elements need to move in relation to each other. However, the way in which intraneural components interact is poorly understood. Previous work identified a distinct core and sheath in the rat sciatic nerve and provides a useful model with which to investigate this interaction. Here we have focused on identifying the mechanical and anatomical characteristics of the interface between core and sheath. Nerve samples, 15 and 20 mm long, of rat sciatic nerves were harvested and placed in a purpose-built jig, and a tensile testing machine was used to pull core from sheath. Mechanical tests of specimens in which core had been previously pulled from sheath by 25% of its initial length achieved a mean pull-out force approximately six times smaller than that achieved using intact controls. These results are consistent with the proposal that core,sheath interactions involve physical connections rather than a viscous fluid interface. Anatomical features of this interface were characterised using transmission electron microscopy. It appeared that sheath was derived from epineurium and most of the perineurium, whilst core consisted of endoneurium and a small proportion of the perineurium: the plane of cleavage appeared to involve the innermost perineurial cell layer. [source]

The Effect of Ovariectomy and Estrogen on Penetrating Brain Arterioles and Blood-Brain Barrier Permeability

MICROCIRCULATION, Issue 8 2009
Marilyn J. Cipolla
ABSTRACT Objective: We investigated the effect of estrogen replacement on the structure and function of penetrating brain arterioles (PA) and blood-brain barrier (BBB) permeability. Materials and Methods: Female ovariectomized Sprague-Dawley rats were replaced with estradiol (E2) and estriol (E3) (OVX + E;N=13) and compared to ovariectomized animals without replacement (OVX; N=14) and intact controls (CTL, proestrous; N=13). Passive and active diameters, percent tone, and passive distensibility of pressurized PA were compared. In addition, BBB permeability to Lucifer Yellow, a marker of transcellular transport, was compared in cerebral arteries. Results: Ovariectomy increased myogenic tone in PA, compared to CTL, that was not ameliorated by estrogen treatment. Percent tone at 75 mmHg for CTL vs. OVX and OVX + E was 44±3% vs. 51±1% and 54±3% (P<0.01 vs. CTL for both). No differences were found in passive diameters or distensibility between the groups. BBB permeability increased 500% in OVX vs. CTL animals; however, estrogen replacement restored barrier properties: flux of Lucifer Yellow for CTL, OVX, and OVX + E was (ng/mL): 3.4±1.2, 20.2±5.3 (P<0.01 vs. CTL), and 6.15±1.2 (n.s.). Conclusions: These results suggest that estrogen replacement may not be beneficial for small-vessel disease in the brain, but may limit BBB disruption and edema under conditions that cause it. [source]