bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal advantage of pale coloured morphs of the snail Arianta arbustorum (Helicidae, Pulmonata) in alpine habitats
Authors: Burla Hans , Gosteli Margret 
Published: July 2006

In alpine grasslands pale colour morphs of the snail Arianta arbustorum are more frequent than dark ones As pale morphs absorb less solar radiation, they may forage for longer in sunlight and/or have a lower mortality risk from overheating This hypothesis was tested Equal numbers of pale and dark morphs were kept in enclosures in an alpine meadow During the day, more pale morphs were seen than dark ones, the latter obviously remaining hidden The difference was not significant in enclosures set up in a nearby forest, confirming that the inequality in behaviour depends on the amount of sunlight Dark snails are on average warmer than pale onesExperiments were also conducted in grassland on a mountain slope at altitudes between 1200 and 2000 m Snails were marked with a paint which fades in light, and released When recaptured several days later, the marks were more faded in pale morphs than in dark, suggesting that they had been more exposed to sunlight, supporting our hypothesis The difference in fading was more pronounced at high than at low altitude
Colonization of new host plant individuals by locally adapted thrips
Authors: Karban Richard , Strauss Sharon Y. 
Published: July 2006

This study considered the dispersal and subsequent reproduction of Apterothrips aptens a wingless, folivorous thrips species that is divided into local populations, each adapted to its individual host plant We placed host plants with no thrips into the field and observed the rate at which thrips colonized these plants Colonization events were rare, on average each pot received 1 47 immigrants during the year Immature thrips were found associated with 64 59c of these events, indicating that reproduction had occurred Colonization was most likely to occur during the summer Most colonists walked onto the new host and airborne movements were very rare Plants that were located far from near neighbors were less likely to be colonized although the size of nearby source populations did not influence the rate of colonizationThese results suggest that limited movement is associated with division of this population into isolated demes Limited movement appeared to be more important as a barner to successful colonization than was demographic success following arrival at a new host plant
Prey selection in coastal Eurasian otters Lutra Iutra
Authors: Heggberget Thrine Moen , Moseid Kjell‐Erik 
Published: July 2006

Prey preferences and dietary differences between sex and age categories of Eurasian otters were studied in coastal Norwegian habitats Relative to their trapping frequency potential prey species with hard, spiny exoskeletons (crabs and sea urchins) or otherwise tough, spiny integuments (Labridae) were much less frequently found in spraints than fish species with soft integuments Spines did not protect fish with otherwise soft integuments from otter predation The number of non‐fish taxa per otter stomach did not vary significantly between otter age categories despite presumed differences in hunting abilities (small cubs large cubs and subadults, adults) Relative frequency of occurrence of crabs and sea urchins was < 5% in the stomachs in each of these otter categories Anadromous, katadromous and freshwater fish species were infrequently eaten The coastal otter population during the study period probably had access to an adequate, and preferred, supply of marine fish preyAt the otter population level no prey size selection was conclusively demonstrated within the range of fish sizes sampled However, fish sizes eaten differed significantly between otter sex and age categories The fish sizes per stomach were on average larger in males than in females, regardless of age Adult males tended to eat the largest fishes Among the self provisioning age categories (subadult and adult otters) fish lengths differed significantly between otter males and females, but not between the otter age categories, and did not covary significantly with otter body length Fish eaten by females with old placental scars (potential mothers of fisheating cubs) were significantly smaller than those eaten by small cubs, provisioned by their mothers
Regeneration of surgically removed buccal alveolar bone in dogs
Authors: Nyman Sture , Karring Thorkild 
Published: July 2006

The aim of the present study was to examine if the establishment of a new fibrous attachment to the root surfaces is accompanied by regeneration of surgically romoved buccal alveolar bone.The experiments were carried out in two dogs with healthy periodontal conditions. The marginal 5–7 mm of the buccal alveolar bone between the mesial and distal line angles of each root of one maxillary second and one mandibular third premolar in both dogs was removed after elevation of a muco‐peristeal flap. During this procedure attempts were made to minimize the mechanica injury to the root cementum and the supraalveolar connective tissue attachment. A notch was prepared in the root surfaces at the level of teh surgically esablished bone crest. This notch served as a landmark for measurements to be made in histological sections. The flaps were repositioned and sutured with interrupted mattress sutures. During the entire experimental period, meticulous plaque control was maintained. In each dog. the contralateral teeth served as non‐treated controls. The animals were sacrificed 8 months after sugery and sections of all test‐and control areas prepared for light microscopic examination.The results of the study demonstrated that in all experimental areas, new cementum formation and fibrous reattachment occurred in the supraalveolar area between the marginal bone crest and teh junctional epithlium. In only two out of eight test areas did the alveolar bone regenerate to or close ot the normal distance from the apical portion of the junctional epithelium whereas in the remaining six areas, a long supracrestal connective tissue attachment was present.
The structure and function of periodontal innervation
Authors: VAN Steenberghe D. 
Published: July 2006

The histology of periodontal innervation in man and of the neural endings in the periodontal ligament in particular remains a controversial matter. Quantitative ultrastructural studies are needed and would help clarifying some functional characteristics of periodontal mechanoreceptors. Most of these characteristics are comparable to those of tegumental receptors elsewhere in the body. Some discrepancies exist however between the findings in perpheral afferent nerves and the findings in the intra‐crainal centres.Concerning the functional significance of periodontal reeceptors, the jaw‐opening reflex and the silent period in jaw muscle activity are related to each other, and their importance is questioned. Although much work has been accomplished on the silent period, the concurrent monosynaptic reflex has been mostly neglected and it has not been demonstrated whether periodontal receptors are the only origin of these reflexes.The perdominant role of periodontal receptors in detecting and discriminating forces acting on a tooth and in the control of the mandibular position when an occlusal contact is present has been proven.
The relationship between gingival inflammation and resistance to probe penetration
Authors: Robinson P. J. , Vitek R. M. 
Published: July 2006

The present investigation was carried out to determine the location of the periodontal probe tip when various loads are applied. Additionally, the role of gingival inflammation to probe resistance was evaluated.The sample consisted of 51 teeth scheduled for extraction. The Gingival Index (GI) was used to establish the degree of inflammation. A loading of 20,25,30 ponds was delivered by a spring loaded sleeve bearing probe fitted with a michigan 0 probe having a terminal diameter of 0.35 mm. The extracted teeth were fixed and then stained with 4% toluidine blue. Using a coronal reference groove and the apical margin of the connective tissue attachment (CTA) as reference points apical penetrtion of the probe was established.The results of this study indicate that there is a linear relationship between the GI and the resistance of the gingival tissues to probe penetration. This is most apparent between a GI = 0 amd GI = 3. Wjereas with 30 ponds the mean penetration at GI = 0 was 0.30 mm. coronal to the CTA, the mean penetration was 1.25 mm apical to the CTA at GI = 3.
Evidence suggesting the presence of antigen‐antibody complexes on the surface of salivary leukocytes
Authors: Sonis S. T. , Mirando D. M. , Lamster I. B. , Stelos P , Wilson R.E. 
Published: July 2006

Fc receptors of salivary leukocytes were studied in twelve patients using sheep red blood cell rosetting techniques. The number of salivary leukocytes having funcitonal Fc receptors was less than expected and was thought to be due to the presence of antigen‐antibody complexes on the surface of leukocytes.Since immune complexes are known activators of neutrophils, we hypothesized taht glucose metabolism in the hexose monophosphate shunt by salivary neutrophils should be greater than a comparable cell population from peripheral blood. Using an assay to assess the metanolism of 14c‐labeled glucose, it was found that salivary leukocytes were more active than peripheral blood leukocytes and that the ability of salivary leukocytes to be extrinsically activated was less than peripheral blood leukocytes. The data suggests that immune complexes area probably present on the surface fo salivary leukocytes and that such complexes are able to modify the surface receptors and functional capacity of these cells.
Effects of repeated scaling and root planing and/or controlled oral hygiene on the periodontal attachment level and pocket depth in beagle dogs
Authors: Morrison E. C. , Lang N. P. , Löe H. , Ramfjord S. P. 
Published: July 2006

This study was performed to evaluate the effect of initial and/or repeated subgingival scaling with or without controlled oral hygiene on the level of periodontal attachment and pocket depth in Beagle dogs. furthermore, the effect of repeated scaling on the progression of naturally developed periodontitis was to be determined.At baseline, and at 1,6,12,24 and 36 months clinical parameters for plaquen deposits (PII), calculus (CI), gingival health (GI) periodontal attachment from the cementoenamel junction (CEJ) and pocket depth were recorded by the same examiner.Eight healthy Beagles, 3 1/2–6 years of age with moderate naturally developed periodontal desease were divided into experimental and control animals. In the experimental group, 4 dogs received a thorough scaling and root planing at the start of the experiment. thereafter the experimental dogs were subjected to daily toothbrushing and a rubber cup and pumice prophylaxis every two weeks. The remaining 4 control dogs were not subjected to any oral hygience measures.Two quadrants diagonally opposed in each animal (experimentaal and control) were scaled and root planed every six months.In the experimental group a significant increase in attachment level was maintained throughout the study. Initial scaling followed by oral hygiene reduced pocket depth singificantly and pocket reduction was maintained over the three year period. Repeated scaling did not influence the mainternance of the attachment level or the reduction in pocket depth in the experimental group. The control animals continued to lose attachment and pocket depth increased during the study. Scaling every six months without oral hygience resulted in loss of attachment and increase in pocket depth, although the rate of attachment loss was retarded.It is concluded that following initial scaling conticuous removal of bacterial plaque is essential for the maintenance of periodontal attachment. In moderate periodontal disease the levels of attachments may be maintained without surgical therapy.
Improvements of in vitro cell‐material adhesion measurements
Authors: Fletcher Ronald D. , Adamiak John K. , Labant Maryann C. , Abertson John N. 
Published: July 2006

The in vitro measurement of gingival cell‐bacto agar substratum adhesive‐bonding strength (γa) is described as it relates to cell‐ concentration, cell‐substratum contact time and serum concentration. These three factors are critical in obtaining reprocible γa's for gingival cell‐test substratum interactions.Cell concentrations of less than 35 × 103 cells per cm2 gave low γa's (70–75 ergs/cm2) whereas 90–130 × 103 cells/cm2 resulted in γa's of 109–119 ergs/cm2, respectively. Maximum γa's (123 ergs/cm2) resulted after the cells had been in contact with the agar substratum for 24 hours. The adhesive‐bonding strenth after eight housrs of contact time, however, was not statistically different from the 24 housr readings and has the advantage of decreasing the test duration. Serum, and important factor for optimum adhesion measurements, produced a peak γa at the 10 % concentration.
Cytoplasmic polarization of periodontal ligament fibroblasts
Authors: Garant Philias R. , Cho Moon‐Il 
Published: July 2006

The fibroblasts of the periodontal ligament and especially those of the transseptal ligament are characteristically elongated with their long axes parallel to the principal fiber bundles. Their cytoplasmic orgamelles are polarized suggesting that secretory products are released from one end of the cell. The nucleus occupies the anterior pole of the cell. Cytoplasmic processes or lobopodia, containing numerous cytoplasmic filaments, extend from the anterior pole of the cell. The Golgi complex is situated in a large area of the cell between the nucleus and the distal end of the cell. Granular endoplasmic reticulum, mitochondria and numerous small vesicles are dispersed throughout most part of the cell. Intracellular collagen, akthough present in many areas of the cell, appears to be most abundant in the distal parts of the cell. Administration of colchicine in vivo, blocked collagen secretion and dereased cell elongation and polartity.Results of and analysis of the orientation and polarization of the fibroblasts in the periodontal tissues appear to support the concept that these cells undergo active migration in vivo along existing substrata and that migration may be coupled to collagen secretion.
The in vitro differentiation of cat sulcular epithelium
Authors: Innes P.B. 
Published: July 2006

The in vitro defferentiation of the sulcular epithelium from cats was studied. Gingival tissues were removed from the labial aspect of the canine teeth of 6 adult cats. These specimens were cultured on stainless steel rafts in organ culture dishes for 3 days. At the end of this period the specimens were examined in the light and electron mecroscopes. It was found that the sulcular epithelium, which at the time of explantation was a nonkeratinized epithelium, developed into a keratinized stratified squamous epithelium afer 3 days in vitro.The results demontrated that sulcular epithelium possesses the potential to keratinize and it is suggested the that enviornmental factors are important in the in vivo differentiatio of this tissue.
Pathological changes caused by the injection of lipids isolated from Gram‐positive organisms into the gingiva of rats
Authors: Irving J. T. , Heeley J. D. , Amdur B. H. , Socransky S. S. 
Published: July 2006

Extractable lipids from Actinomyces naeslundii, strain I, and streptococcus mutans (6715) were injected in the oral mucosa of weanling rats. Whole lipid, neutral lipid, glycolipid and phospholipid fractions were compared with synthetic tripalmitolein. The animals were sacrificed at intervals, 6 hours to 14 days, and the tissues examined histologically.Lipids from A. naeslundii resulted in an initial polymorphonuclear response, gradually replaced by lymphocytes with time. Effects on the underlying alvolar bone included disaaperance of osteoblasts, empty osteocyte lacunae, and in a few cases, bone resorption. An accumulation offibrillar debris was also seen as early as 18 hours, persisiting up to 96 hours. post‐injection.Lipids from S. mutans resulted in a marked lymphocyte infiltration preceded by a very slight PMN response, similr changes in underlying bone, and no evidence of fribrillar debris. Recovery of osteoblasts along the underlying bone was slowest with the phospholipid fractions and fastest with neutral lipids seeming to correlate with their respective toxicity. The cell reaction to synthetic triplamitolien was similar to that elicited with the neutral lipid fractions but of shorter duration. In this system lipids from A. naeslundii were apparently more toxic than those from S. mutans.
A microbiological study of dental calculus
Authors: Sidaway D. A. 
Published: July 2006

Deposits obtained from the in vitro calcificaqtion of vialble adn formalin killed microorganisms have been examined by Von Kossa staining and X‐ray diffraction analysis. 34 of the 35 species examined were isolated from, and represcented, the flora of human calculus.Twenty‐one of the viable and 23 of the formalin‐killed cultures gave positive Von Kossa smears but idebntical results for live and dead preparations were obtained in only 25 of the 35 organisms examined. In viable cultres only, teh proportion of calcified organisms increased with time suggesting that degenrative change is probably a prerequistie for cellular calcification.The X‐ray diffraction analysis shwed that in clacified viable cultures hydroxyapatitie was always found (22) and in the majority of cases (18) was the sole from of crystalline with octocalcium phosphate and/or brushite (10), gave a weaker pattern than that given by similar viable cultures.In 9 deposits octocalcium phosphate and brushite were the only form s of calcium phosphate detected adn 6 of these gave positive Von Koss smears. The formation in vitro of these two forms suggests that, as previously recorded for hydroxyapatiti, the plaque microbiota may play a part in theri in vivo formation.
Preliminary characterization of material eluted from the roots of periodontally diseased teeth
Authors: Fine D. H. , Morris M. L. , Tabak L. , Cole J. D. 
Published: July 2006

Eighteen periodontally diseased teeth and eleven normal teeth requiring surgical removal were each treated with one of four different solutions to elute potentially toxic material from their root surfaces. The solutions used were pyrogen‐free water, phenol‐water, trichloroacetic acid and citric acid. To define the composition of the eluted material, samples were analyzed for calcium, for ketodeoxyoctonic acid (KDO), a carbohydrate unique to Gram‐negative bacteria, and for limulus lysate activity. Limulus‐positive material was then analyzed for protein and nucleic acids and subjected to heat treatment, to the enzymes RNAse A and T1, and to lysozyme.It was found that TCA and citric acid removed more calcium and more toxic material from the root surface and subsurface than did either water or phenol‐water.The material extracted from 13 of the 18 diseased roots was limulus‐positive. Four of the limulus‐positive samples were also KDO‐positive, strongly indicating the presence of endotoxin in these samples. Neither these nor any of the other limulus‐positive responses were reversed or significantly reduced by exposure of samples to heat, to RNAse A and T1, or to lysozyme. In addition, limulus‐positive responses were unrelated to the amounts of protein and nucleic acids in the extracted material.When considered together, these preliminary characterizations indicate the presence of endotoxin in the material eluted from periodontally diseased teeth.
The subgingival microbial flora during pregnancy
Authors: Kornman Kenneth S. , Loesche Walter J. 
Published: July 2006

The subgingival bacterial flora from 2 gingival sites was cultured and characterized monthly in twenty periodontitis‐free women during pregnancy and again post‐partum. Monthly plaque samples were also cultured in eleven age and disease matched non‐pregnant women. Plaque was processed anaerobically on selective and nonselective media and the predominant colony types were characterized. A portion of each plaque sample was tested for bacterial uptake of C14‐estradiol and C14‐progesterone. Plasma levels of estrogens and progesterone were measured four times in each subject. The number of gingival bleeding sites, the Gingival Index and the Plaque Index were determined at each sampling period.In the second trimester there was a significant increase in gingivitis, the ratio of anaerobic to aerobic bacteria, and the proportional levels of Bacteroides melaninogenicus ss. intermedius. In the third trimester both gingivitis and the levels of B. melaninogenicus ss. intermedius decreased. Plaque uptake of C14‐steroids increased significantly during pregnancy and paralleled the plaque levels of B. melaninogenicus ss. intermedius. In the second trimester, recovery of B. melaninogenicus ss. intermedius was strongly correlated with plasma levels of estrogens and progesterone. No changes were observed in clinical parameters or the subgingival flora of non‐pregnant subjects.Pregnancy and specifically steroid hormones appear capable of influencing the normal bacterial flora and inducing alterations in the subgingival ecology.
Activation of complement by dental plaque
Authors: Okuda Katsuji , Takazoe Ichiro 
Published: July 2006

Dental plaque samples and oral bacterial cells consumed complement (C) in human serum. No significant difference was found between the C binding ability of dental plaque samples from patients with periodontal disease and those of samples from healthy individuals. An analysis of C component profiles and immunoelectrophoretic patterns showed that dental plaque activated the C system through the alternative pathway as well as the classical pathway.When pooled and dispersed dental plaque was preincubated with fresh serum, the purified C3 conversion and C3 cleaving were observed. The activity of the pretreated dental plaque disappeared gradually by further incubation with fresh serum at 37°C. These results suggest that dental plaque generates the C3‐cleaving enzyme activity.
Electron microscope quantitation of inflammatory infiltrates in childhood gingivitis
Authors: Longhurst Peter , Gillett Roy , Johnson Newell W. 
Published: July 2006

Quantitation of inflammatory cell infiltrates in gingival connective tissues was carried out on 12 gingival biopsies from the deciduous dentition of 11 children aged 4–8 years. The tissue was prepared for electron microscopy and from ultrathin sections mounted on 200 mesh grids, cells in one third of the grid squares enclosing infiltrated connective tissue were counted.The infiltrate displayed large numbers of small and medium lymphocytes and was moderately vascular. A distinct population of peripherally distributed plasma cells was present and pathologically altered fibroblasts together with marked collagen loss were notable features. Small numbers of macrophages, mast cells and polymorphonuclear neutrophils were recorded but T‐blasts (immunoblasts) were very rarely encountered.The childhood lesions have much in common with the early lesion of adult gingivitis which is considered to be a cell‐mediated immune phenomenon. However, the lack of T‐blasts and rather larger proportion of plasma cells suggest that the lesion of childhood gingivitis represents a position between the early and established phases of gingival disease described in older individuals. A more exact interpretation of these, the earliest stages of human gingival disease should be achieved when the lymphocytes contributing to the childhood infiltrates can be assigned to the T‐ and B‐ cell lines.