bluuebunny/crossref_metadata_2025_split huggingface dataset:
The uptake of H3‐estradiol by the oral tissues of rats
Authors: Formicola Allan J. , Weatherford Thomas , Grupe Harold 
Published: June 2006

This study was designed to determine whether H3‐estradiol would localize in the oral tissues of rats. Twenty ovariectomized rats were injected subcutaneously with H3‐estradiol. After injection, oral tissue including gingivae and mucosa, submandibular gland, liver, kidney, uterus and skin were dissected, weighed and homogenized. The tissues were assayed for H3‐estradiol and 5 ml aliquots added to liquid scintillation fluid. The samples were read on a Beckman Liquid Scintillator.A series of experiments using the above technique demonstrated the following: (1) H3‐estradiol concentrated in the oral extract when a dose of 0.136 μg/100 gm body weight or greater was given. (2) The assay of oral extract contained H3‐estradiol as evidenced by chromatography. (3) One hour after injection the oral extract had the highest concentration of H3‐estradiol (212 CPM/mg of tissue) while the uterus remained low (47.7 CPM/mg) in uptake. Four hours after injection there was a statistically significant increase of H3‐estradiol in the uterus (118.5 CPM/mg but not a significant decrease of H3‐estradiol in the oral extract (131.8 CPM/mg). (4) Estrogen (Progynon)* priming for 7 days reduced the uptake of H3‐estradiol in the oral extract.Since H3‐estradiol concentrates in the oral extract, it is suggested that estrogen can influence the gingival tissues on a local cellular level. The fact that estrogen priming reduced the uptake of H3‐estradiol in the oral extract indicates that there may be some type of binding site in the gingivae and mucosa.
Electron microscopic studies of human tooth development
Authors: Sisca Rodger F. , Provenza D. Vincent 
Published: June 2006

This study present an ultrastructural characterization of the prospective gingival epithelium in the human embryo during the third and fourth months of development.The surface cells were squamoid and interdigitated. The central cell layer was composed of more rounded cells while those of the basal layer were cuboidal to low columnar. The intercellular spaces were fewer and smaller toward the free surface. Differences in the number, variety and organizational aspects of the junctional complexes were noted relative to level of location. Hemidesmosomes were observed at the basal cell‐connective tissue interface. Pronounced differences in the kinds and number of organelles were noted at the various epithelial levels. In the surface cells, glycogen was accumulated throughout the cell and organelles were reduced in number. As the glycogen diminished in the cells toward the basal region, the organelle complement increased. The arrangement of tonofilaments tended to change toward the superficial layers. The larger masses were located in the deeper and central cells while surfaceward, tonofilaments were diffusely distributed.
Lactate dehydrogenase isoenzymes of the human periodontal ligament
Authors: Hllldén Leif , Linde Anders , Ljunggren Anna 
Published: June 2006

The isoenzymes of lactate dehydrogenase (E. C. 1. 1. 1. 27.) from the periodontal ligament on the root surface of extracted erupted permanent human teeth have been separated and quantitated by means of cellulose acetate membrane electrophoresis.LDH‐3 and LDH‐4 were the predominating isoenzymes. and smaller amounts of LDH‐2 and LDH‐5 were also present. Only traces of LDH‐1 could be seen. The results indicate the presence of both aerobic and anaerobic metabolic pathways in the human periodontal ligament.These pathways bring about an efficient, economical energy production under normal circumstances, and make the survival of this tissue possible under hypoxic conditions, when the blood supply is briefly interrupted. The results further show that determinations of the survival time of the periodontal ligament on a tooth outside its alveolus have to be made by activity measurements of both aerobic and anaerobic enzymes.
Crown and root length, and root‐crown ratios of lower incisor teeth of mongoloid, non‐mongoloid retarded and normal individuals
Authors: Brown R. H. 
Published: June 2006

Crown and root lengths were measured and root‐crown ratios calculated for lower incisor teeth of mongoloid (M), non‐mongoloid retarded (NM) and normal (N) subjects. The teeth from all subjects had been extracted for periodonlal disease except those teeth from normal children which had been extracted for orthodontic reasons.Both crowns and roots of the M teeth were shorter than NM and N teeth. Crowns of the teeth from older mongoloids and non‐mongoloids tended to be shorter than those of younger patients, probably due to attrition. However the roots of the teeth of older mongoloids were longer than those of younger mongoloids; in all cases root formation was complete. Regression analysis showed that the root‐crown ratios of the mongoloid central and lateral incisors and non‐mongoloid lateral incisors were positively related to age (P < .05). This association was related to attrition in the NM and N teeth, whereas for M teeth, the association was influenced by root length.It was considered that short roots and unfavourable root‐crown ratios of incisor teeth in the mongoloid children may contribute to early mobility and subsequent tooth loss.
The Dynamic stiffness of toothbrushes
Authors: Macfarlane D. W. 
Published: June 2006

Using strain gauges, the method to be described measures the lateral force required to produce a standard deflection of toothbrush tufts. A deflector bar which remains stationary is attached to a cantilever which is stressed by the pressure of the brush moving across the deflector bar. The resulting strain is measured by using strain gauges which are connected via a Wheatstone bridge to an oscilloscope. Movements of the oscilloscope beam represent changes in the force exerted by the brush and are photographed on moving film.The effects on stiffness of changes in the rate of strain, length, diameter, wetness and temperature of nylon were investigated separately, and a standard test was devised which could assist in more accurate labelling of toothbrushes.
Histological changes in experimental periodontal disease in gnotobiotic rats and conventional hamsters
Authors: Irving J. T. , Socransky S. S. , Heeley J. D. 
Published: June 2006

Seventy‐six weanling gnotobiotic rats of the Sprague‐Dawley strain were monoinfected in groups with Actlnomyces naeslundii, Actinomyces viscosus or Streptococcus mutans. The animals were killed at intervals up to 84 days and the maxillae and mandibles examined histologically. Periodontal disease, as evidenced by the presence of plaque, migration of the epithelial attachment and regression of the alveolar bone was sometimes evident after 28 days and in all cases extreme by 84 days. No organisms were seen in the gingiva and inflammatory changes were slight. Periodontal disease was most marked between the first and second maxillary molars, the mandibular gingiva, apart from the presence of plaque, being normal over the experimental period. Bone loss was gauged by labelling the bone with 3H proline, and osteoclasts were detected by the acid phosphatase technique.In another experiment, 44 conventional weanling cream hamsters were superinfected with A. naeslundii. Periodontal disease developed more slowly than in the gnotobiotic rats, usually taking about 160 days to be severe.In both experiments the pathological changes were similar. The gnotobiotic rats developed periodontal disease over the same time sequence with all three organisms. Bone loss was not accompanied by the presence of osteoclasts and seemed, in this model, to be more due to a gradual cessation of bone formation than to active resorption. If in addition bone resorption did occur, it was brought about by a mechanism at present undescribed.
Experimental contact hypersensitivity in the gingiva of dogs
Authors: Nobréus Nils , Attström Rolf 
Published: June 2006

Application of l‐dinitro‐2.4‐chlorbenzene (DNCB, 0.05 % in Orabase®) onto the gingiva in one side of the jaws was performed daily for six days in a group of sensitized dogs. Contralaterally only the vehicle was applied. Anti‐thymocyte serum (ATS) was injected into the dogs after three days of application. The effects on the gingiva were studied by inflammatory cell counts in sections of gingival biopsies and by measurements of crevicular leukocytes, gingival fluid and acid phosphatase activity in crevicular samples.The numbers of inflammatory cells in the gingival biopsies as well as the figures of the gingival crevice parameters were higher in the DNCB side as compared to the control side on day 3. Immuno‐suppression with ATS affected all parameters as observed from the data of day 6 of the experiment. The results of the study indicate that gingival contact hypersensitivity to DNCB can be elicited in beagle dogs and that this reaction is reflected in crevicular parameters of gingival inflammation.
Effect of chlorhexidine gluconate on granulation tissue
Authors: Helldén L. , Lundgren D. , Heyden G. 
Published: June 2006

A well defined cavity surrounded by granulation tissue was created by subcutaneous implantation of perforated Teflon® cylinders. A 0.2 % solution of chlorhexidine digluconate or physiological saline was injected into the cavity five and ten days after the implantation.The acute inflammatory reaction in the recipient area was estimated from the amount of exudate and the number of inflammatory cells in the cylinder cavity. The recipient tissue was also examined histologically. The injection of chlorhexidine resulted in a slightly larger increase of the acute inflammation than did saline.Furthermore, after injection of chlorhexidine the fluid‐filled area of the cavity showed stroma of precipitated material.
The role of gingival connective tissue in determining epithelial differentiation
Authors: Karring T. , Lang N. P. , Löe Harald 
Published: June 2006

Free grafts of connective tissue, without epithelium, were transplanted from either the keratinized gingiva or the non‐keratinized alveolar mucosa (controls) into areas of the alveolar mucosa in seven monkeys. The grafts were placed in pouches created in the connective tissue as close as possible to the overlying epithelium. After 3–4 weeks, the transplants were exposed by removal of the overlying tissue in order to allow epithelialization from the surrounding non‐keratinized alveolar mucosa. The transplants were examined clinically and histologically at time periods between 1 and 12 months.The gingival connective tissue grafts became covered with keratinized epithelium displaying the same characteristics as those of normal gingival epithelium. The alveolar mucosa transplants were covered with non‐keratinized epithelium. This indicates that gingival connective tissue is capable of inducing the formation of a keratinized gingival epithelium.
Complement factors in gingival crevice material from healthy and inflamed gingiva in humans
Authors: Attströum Rolf , Laurel Anna‐Brita , Lahsson Ulf , Sjöuholm Anders 
Published: June 2006

The presence and levels of complement factors C3, C4, C5, and C3 proactivator, were determined by electroimmuno assay in gingival crevice material from five individuals with healthy gingiva and from six patients with chronically inflamed gingiva. Higher concentrations of C3 and C4 were found in samples from chronically inflamed gingiva when compared to those from healthy gingiva. The amount of C3 in material from healthy as well as from inflamed gingiva was related to that in plasma, when the albumin in plasma and gingival crevice material was used as a reference. The same was found for C4 in samples from healthy gingiva but in those from inflamed gingiva, the values were significantly lower when related to plasma levels. C5 could not be found in material from healthy gingiva but was present in material from inflamed gingiva. C3 proactivator was present in material from inflamed gingiva in the converted form. No C3 proactivator was found in material from healthy gingiva with the methods used.Analysis of C3 in samples from inflamed gingiva, using crossed immunoelectrophoresis, showed that C3 was converted in these samples.The results indicate that the complement system may be activated in gingival crevice material from inflamed gingiva.
Partial‐mouth recording of plaque and periodontal pockets
Authors: Mills William H. , Thompson Gordon W. , Beagrie George S. 
Published: June 2006

Plaque and pocket depths, were recorded in millimetres from the tissue margin, coronally or apically, respectively. Plaque and pocket depths were recorded by examining only a segment of the dentition using eight different combinations of teeth. These results and the results obtained from full ‐ mouth examinations in the same individuals were compared.All eight methods of partial‐mouth recording gave results that were good in terms of both relative and absolute value when compared to the total‐mouth index. The results were valid irrespective of the method chosen. The anterior tooth index was preferred because this segment of the dentition was the easiest to examine. It eliminated the difficulty of making the decision of which teeth to substitute when any of the other teeth were missing and produced results for plaque scores and pocket scores that were very good estimates of the total‐mouth index.
A histological and scanning electron microscopy study of the muco‐gingival junction in the vervet monkey
Authors: Fleisch L. , Cleaton‐Jones P. , Austin J. C. 
Published: June 2006

Specimens of clinically healthy oral epithelium from the vervet monkey (Cercopithecus aethiops) containing gingiva, alveolar mucosa and muco‐gingival junction were examined histologically and with the scanning electron microscope.The gingiva was covered by a stratified squamous keratinized epithelium and the alveolar mucosa by a non‐keratinized stratified squamous epithelium. A groove was present between the two epithelia in approximately half the specimens, the floor of which was lined by keratinized epithelium. Non‐keratinized epithelial cells were seen to interdigitate with keratinized cells at the base of the alveolar mucosa side of the groove.
Hidden Rechargea
Authors: Feth J. H. 
Published: July 2006

Abstract“Hidden recharge” is defined as subsurface percolation of water from basin‐margin mountains directly into aquifers of the valley basins. It is an important, and sometimes neglected, item in hydrologic equations. Locally, geologic conditions permit inter‐basin circulation of ground water. The concept that ground‐water basins necessarily terminate at the contact between alluvium and hardrock is not tenable.
Exploration for Artesian Water in the Sokoto Basin, Nigeriaa
Authors: Anderson H. R. , Ogilbee W. 
Published: July 2006

AbstractThe Sokoto basin in semiarid northwestern Nigeria contains Cretaceous and Tertiary semiconsolidated deposits that dip gently northwest off an oldland of pre‐Cretaceous crystalline rocks. Until recent years the dug well has been the chief source of ground water for the Hausa cultivators and the pastoral Fulani inhabitants of the region. Borehole exploration sponsored by US AID and the Geological Survey of Nigeria with technical guidance from the writers of the U. S. Geological Survey has revealed that the basal section of the Gwandu Formation contains a productive artesian sand aquifer throughout a 5,700 square mile area. Transmissibilities of the aquifer proved to be as high as 180,000 Imperial gallons a day per foot but generally decrease towards the west. The free flow areas total about 1,000 square miles with pressure heads in boreholes up to + 83 feet above land surface and individual flows as great as 12,000 gallons per hour. Beneath the Gwandu, pressure aquifers in the Rima Group and the Gundumi Formation also produce flowing water in the lowland (fadama) of the Sokoto River. In the southern part of the basin, however, only one aquifer is present in the Cretaceous sequence, because the Gundumi aquifer is absent and the Rima aquifer apparently grades into the upper permeable section of the Illo Group. The quality of the water from all the pressure aquifers is generally quite good, although the iron content is high in places and salinity increases in the very deep aquifers.In Sokoto Province more than 2 million people and their livestock use less than 5 mgd of water drawn from dug wells and about 1 mgd from boreholes. The newly discovered flowing artesian water can do much to improve the water supplies of remote villages in the province and even supplement river irrigation during the dry season in the fertile fadama.
Analysis of Shallow Hard Rock Well Pumping and Recovery Test Dataa
Authors: Zdankus Narimantas T. 
Published: July 2006

ABSTRACTIn this paper equations for calculation of steady, unsteady, confined and unconfined radial ground‐water flow to wells are compared and unified by a single general equation. The validity of the equation is expanded by applying it to a shallow hard rock aquifer where hydraulic conductivity varies with depth. Recommendations are given as to employment of said equation for analysis of pumping and recovery test data of shallow hard rock bore and dug wells.The suggested method for analysis of bore well test data is based on the principle used by Jacob in his method (1950). Drawdown function as function of time is used for graphical analysis of test data. Because of seepage face phenomenon, drawdown measured in water‐table wells must not be used for computation of drawdown function. The function to be computed from drawdown is measured in the aquifer.Hydraulic conductivity is determined from dug well test data as a function of ground‐water inflow into the well discharge which varies during pumping and recovery test because of significant accumulating capacity of the well. Specific yield for the calculation is assumed according to the type of rock, and radius of influence is expressed as a function of time.Derived equations can be used also for hydraulic computation of shallow hard rock water‐table wells.
Nonpoint Nitrate Contamination of Ground Water in Merrick County, Nebraskaa
Authors: Spalding R. F. , Gormly J. R. , Curtiss B. H. , Exner M. E. 
Published: July 2006

ABSTRACTThe areal distribution of 293 samples from the ground water of Merrick County, Nebraska has definite patterns of high (>20 ppm), intermediate (10–20 ppm), and low (<10 ppm) nitrate‐nitrogen concentrations. Where contamination is present the nitrate‐nitrogen concentrations are relatively homogeneous indicating large diffuse nonpoint sources. SYMAP (gray‐scale mapping) indicates exceptionally good correlation between the irrigated coarse‐textured soils and the higher nitrate‐nitrogen levels. The obvious implication is that the nitrate‐nitrogen levels are directly dependent on the leaching of nitrogenous material dispersed in or on the coarser‐textured soils. The widespread use of commercial nitrogen fertilizer on irrigated corn acreages is suspected of being the major contributor of nitrate to the ground water.
Grout‐Induced Temperature Rise Surrounding Wells
Authors: Molz Fred J. , Kurt Carl E. 
Published: July 2006

ABSTRACTCement grout surrounding a well casing generates heat, called heat of hydration, as it hardens. This heat can raise the temperature of the casing‐grout‐soil system significantly. Because the strengths of plastic casing materials decrease relatively rapidly with increasing temperature, it is important to have some idea of the temperature increase to be expected. Solution of the radial heat‐flow equation predicts temperature rises at the outer casing boundary of 9°C (16.2°F) to 55°C (99°F) as the grout envelope around a 6‐inch, water‐filled casing varies from 1.5 inches to 12 inches. The time required for the peak temperature to be reached varies from 7 to 22 hours. The temperature increase is relatively insensitive to casing diameter and thermal properties of the casing and soil. It is relatively sensitive to the type of cement used in the grout and the material filling the casing while the grout is curing. All types of plastic casing have been used successfully for years. This is due partly to the fact that in most grouting operations from the bottom up, forces on the casing are such that there is little or no tendency for collapse. However, if an air‐filled, plastic casing were grouted from the top down, heat‐induced collapse would be much more likely, particularly in zones where caving took place during well drilling.
Mathematical Modeling of the Biomechanics of the Lamina Cribrosa
Under Elevated Intraocular Pressures
Authors: Newson Tim , El-Sheikh Ahmed 
Published: June 2006

Abstract
Comprehensive understanding of the biomechanical performance of the lamina cribrosa (LC) and the optic nerve head is central to understanding the role of elevated intraocular pressures (IOP) in chronic open angle glaucoma. In this paper, six closed-from mathematical models based on different idealizations of the LC are developed and compared. This approach is used to create further understanding of the biomechanical behavior by identifying the LC features and properties that have a significant effect on its performance under elevated IOP. The models developed are based on thin circular plate and membrane theories, and consider influences such as in-plane pretension caused by scleral expansion and large deflections. Comparing the results of the six models against a full ocular globe finite element model suggests the significance of the in-plane pretension and the importance of assuming that the sclera provides the LC with a clamped edge. The model that provided the most accurate representation of the finite element model was also used to predict the behavior of a number of LC experimental tests presented in the literature. In addition to the deflections under elevated IOP, the model predictions include the distributions of stress and strain, which are shown to be compatible with the progression of visual field loss experienced in glaucoma.
The SloR/Dlg Metalloregulator ModulatesStreptococcus mutansVirulence Gene Expression
Authors: Rolerson Elizabeth , Swick Adam , Newlon Lindsay , Palmer Cameron , Pan Yong , Keeshan Britton , Spatafora Grace 
Published: June 2006

ABSTRACTMetal ion availability in the human oral cavity plays a putative role inStreptococcus mutansvirulence gene expression and in appropriate formation of the plaque biofilm. In this report, we present evidence that supports such a role for the DtxR-like SloR metalloregulator (called Dlg in our previous publications) in this oral pathogen. Specifically, the results of gel mobility shift assays revealed thesloABC,sloR,comDE,ropA,sod, andspaPpromoters as targets of SloR binding. We confirmed differential expression of these genes in a GMS584 SloR-deficient mutant versus the UA159 wild-type progenitor by real-time semiquantitative reverse transcriptase PCR experiments. The results of additional expression studies support a role for SloR inS. mutanscontrol of glucosyltransferases, glucan binding proteins, and genes relevant to antibiotic resistance. Phenotypic analysis of GMS584 revealed that it forms aberrant biofilms on an abiotic surface, is compromised for genetic competence, and demonstrates heightened incorporation of iron and manganese as well as resistance to oxidative stress compared to the wild type. Taken together, these findings support a role for SloR inS. mutansadherence, biofilm formation, genetic competence, metal ion homeostasis, oxidative stress tolerance, and antibiotic gene regulation, all of which contribute toS. mutans-induced disease.