bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
Physiological resorption of connective tissue associated with tooth eruption
Authors: Ten Gate A. R.
Published: June 2006

The ultrastructural changes occurring during physiological resorption of connective tissue associated with erupting teeth of monkeys is described. Significant differences occur before and after the tooth emerges into the oral cavity. Before the tooth erupts connective tissue resorption over the tooth shows a cellular response involving cells of the fibrocytic and monocytic series. The cells of the fibrocytic series show changes from the resting fibrocyte which involve dilation of the cisternae of the rough endoplasmic reticulum, hypertrophy of the Golgi appearatus, the apparance of agranular vesicles, loss of the spiral configuration of polysomes and the development of numerous coated vesicles close to the cell surface. Ultimate breakup of the fibrocyte occurs. Monocytic cells become macrophagic. No breakup of macrophages occurs. In the extracellular compartment the collagen fibrils show a breakup into smaller units and eventual loss. The dental epithelium associated with this disorganized connective tissue is characterized by the development of numerous coated vesicles and a highly vesicular cytoplasm. The connective tissue and dental epithelium lateral to the crown of the tooth showed a similar ultrastructural picture which alters significantly as the tooth emerges into the oral cavity and the epithelial attachment develops. An acute inflammatory response occurs and the connective tissue supporting the forming attachment shows areas of breakdown and synthesis occurring simultaneously. These findings are discussed in terms of the mechanism of connective tissue breakdown and the fibrocyte implicated as playing an important role in this mechanism. It is suggested therefore, that the fibrocyte is capable of modulation to become either synthetic, maintaining or degradative.
The effect fo topical application of Fluorides on the gingival tissues
Authors: Lindhe J. , Hansson B‐O. , Brånemark P‐I.
Published: June 2006

There have been few previous investigations of the possible local effects on the gingivae of topically applied fluoride solutions and the results obtained have been contradictory. In the present study the immediate reaction of dog gingivae to topical application of sodium fluoride in concentrations of 0.2, 1.0 and 2.0 per cent, and the reaction to long term treatment by daily application of 2.0 per cent sodium fluoride solution to clinically healthy and chronically inflamed gingivae were studied. Immediate tissue reactions were assessed from changes of microvascular structure and function (Part 1). The effect of long‐term treatment was estimated from the amount of fluid in the gingival pocket (Part II). Application of sodium fluoride solutions to the crevicular epithelium in variably caused severe dysfunction of the blood vessels in chronically inflamed tissues but never of those in clinically healthy gingiva. Repeated topical applications of 2 percent NaF did not produce chronic gingivitis or aggravate an existing gingivitis.
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.
The reliability of various mitotic index systems in assessing mitotic activity in stratified squamous epithelium
Authors: Karring T. , Löe Harald
Published: June 2006

At various times within a 24 hour period 26 while albino rats aged from 3 to 15 months received an intraperitoneal injection of colchicine (1 mg/kg body weight) and were sacrificed 31/2 hours later. Serial sections were prepared for the palate, tongue, gingiva and ear and were stained with hematoxylin and eosin. The mitotic activity was assessed for the epithelium of these tissues using three different mitotic index systems (mitoses/1 mm2 surface area; mitoses/1000 cells; mitoses/1 mm basement membrane). For the same tissues in another 10 rats the number of nucleated epithelial cells and the length of the basement membrane were related to a reference unit of the epithelial surface. The coefficients of variation for these observations were calculated. The application of the traditional indices (mitoses per 1000 cells or 1 mm of the basement membrane) introduced an appreciable variability into the measurements and produced misleading results when the mitotic activity of various epithelia were compared. The index system expressing the number of mitoses relative to a reference unit (1 mm2) of the outer surface of the epithelium was found to be the most reliable method for assessing mitotic activity in stratified squamous epithelium.
Neutrophil chemotactic activity elaborated by human dental plaque
Authors: Lindhe J. , Helldén L.
Published: June 2006

In the present investigation an in vivo method is described for studying the chemotactic activity elaborated by factors in human dental plaque. Plaque was sampled from the buccal and lingual surfaces of teeth from dental students, who had refrained from mechanical tooth cleansing during one 4 and one 8 day period. The plaque samples were suspended in 0.15 M NaCl, homogenized, and centrifuged at 12,100 × g for 30 minutes at 4°C. The plaque supernatant was then separated from the cellular pellet and sterile filtered through a 0.45 μ Millipore filter. The chemotactic activity elaborated by the filtrates was examined in (i) Boyden's in vitro chamber (ii) a wound chamber model described by Lundgren and Lindhe (1970). The results showed (i) that the wound chamber method is well suited for studying leukocyte chemotactic activity elaborated by dental plaque (ii) that factors in dental plaque stimulate the emigration mainly of neutrophils (iii) that there is no increase in the amount of chemotactic factors/mg plaque with increasing age of the plaque. Data from the wound chamber experiments further revealed that the plaque filtrates tested do not markedly influence the permeability to plasmaproteins and water of granulation tissue vessels.
Cell proliferative activity of injured periodontal tissue
Authors: Stahl S. S. , Tonna E. A.
Published: June 2006

Fifty‐six, female, BNL strain mice, 26 weeks of age, received a modified “gingiveclomy” excising, the gingival papilla mesial to the maxillary left first molar. The right maxillae served as the uninjured control site. Additional non‐injured mice were utilized as further controls. At varying time intervals, groups containing 4 mice each were sacrificed over a 3 months experimental period. One hour prior to sacrifice, each animal received a subcutaneous injection of 1 uCi of H3TDR/gm of body weight. At sacrifice, both left and right maxillae were dissectedd out and prepared for histologic and autoradiographic study. Following injury, the highest proliferative activity was encountered at the epithelial wound edge. This activity became prominent about 8 to 15 days after injury, while the adjacent crestal epithelium demonstrated a markedly increased activity as early as 16 hours after wounding. The reformed junctional and crevicular epithelium, and adjacent fibroblasts, still exhibited elevated activity at one month post‐injury and returned to control range values between one and three month following wounding. The remaining fibroblasts, osteoblasts and cementoblasts around the wound periphery showed markedly elevated activity as early as one to two days post‐injury which returned to control levels between 2 to 4 weeks after wounding.
Hexokinase activity in non‐inflamed attached gingiva of rhesus monkeys
Authors: Bergquist J. J. , Nuki K.
Published: June 2006

Ultramicrochemical methods were used to assay hexokinase activity under optimum substrate mixture concentrations in clinically non‐inflamed attached gingival tissue of Rhesus monkeys. Precautions were taken to assure the clinical non‐inflamed status of the gingivectomy specimens. Frozen dried sections were dissected under a stereomicroscope into representative morphologically distinct fragments which ranged in weight from 14 to 240 nanograms (10−9 grams). Optimum assay conditions were determined in fresh gingival homogenates. Quantitative results for the various strata of epithelium, connective tissue and whole epithelium were calculated. The mean hexokinase activity was reported in micromoles of converted substrate per gram of dry tissue weight per minute at 37°C: surface layer 22.4. granular layer 22.6, spinous layer 18.9, basal layer 15.9, connective tissue 16.6 and whole epithelium 18.0. These results are compatible, for the most part, with hexokinase activity assayed in other epithelial tissue, such as skin of the parietal region of the scalp, plantar surface of the foot and mucous membrane from the lip, all of which are less commonly involved in chronic inflammatory processes than is gingival tissue.
The value of osseous coagulum as a graft material
Authors: Freeman E. , Turnbull R. S.
Published: June 2006

Osseous coagulum is regarded by some clinicians as a useful material for grafting in procedures aimed at bone replacement. Its value in this regard has been assessed experimentally. Holes ∼ 2 mm in diameter were made in the right and left parietal bones of 15 middle‐aged Wistar‐strain albino rats weighing ∼ 500 g. Osseous coagulum was obtained from the interparietal bone, and was placed into the left hole, while the right served as a control. Three of the animals were injected with tetracycline; these animals were sacrificed at 4, 8 and 12 weeks postoperatively, and undemineralized sections of their calvaria were viewed in ultraviolet light to assess accretion of new bone. The remaining 12 animals were sacrificed at postoperative intervals of 1, 2, 3, 4, 8 and 12 weeks, and serial sections of their calvaria were examined by routine histological methods. The observations indicate that, in this system in which repair is normally poor, osseous coagulum consistently did not appear to have induced the formation of new bony callus. These findings bring into question the value of using osseous coagulum as an autograft in clinical periodontal procedures aimed at restoring the attachment apparatus.
Effects of tooth loss on the periodontal condition of neighbouring teeth
Authors: Silness J. , Hunsbeth J. , Figenschou B.
Published: June 2006

The periodontal condition of 100 premolars each of which had lost the distal neighbouring tooth was compared with that of 100 contralateral teeth which had not sustained loss of neighbouring teeth. The periodontal condition was assessed by recording Plaque Index (Silness and Löe 1964), Gingival Index (Löe and Silness 1963), by measuring pocket depth according to Glavind and Löe (1967) and by measuring the distance between the cemento‐enamel junction and the bone margin. The effects of the distal tooth loss seemed to be: reduced accumulation of plaque, reduced soft tissue inflammation, reduced pocket depth and loss of bone on the distal aspects of the premolars.
Gingival recession in tooth types in high fluoride and low fluoride areas
Authors: Murray J. J.
Published: June 2006

The prevalence of gingival recession in individual teeth in 1,884 dentate adults, aged 15–65 years, continuously resident in the natural fluoride area of Hartlepool (1·5–2·0 ppm F) was compared with that found in 2,015 dentate adults from the low fluoride town of York (0.15–0.28 ppm F). In each tooth type, gingival recession increased steadily with age. A distinctive pattern of gingival recession was observed in each community. Mandibular incisors showed the highest prevalence of gingival recession, followed by maxillary first molars, mandibular first molars, premolars, maxillary second molars, mandibular second molars and canines. Maxillary incisors showed the lowest prevalence of gingival recession. There was an extremely high correlation between Hartlepool and York data, for each group of teeth. It was therefore concluded that fluoride in drinking water, at least up to 2 ppm F, has no effect on the pattern of gingival recession in adults.
Chlorhexidine–protein interactions
Authors: Hjeljord L. G. , Rølla G. , Bonesvoll P.
Published: June 2006

The binding of chlorhexidine to proteins in vitro has been shown to involve albumin in both serum and saliva. The binding, which is pH‐ and concentration‐dependent, occurs both to proteins remaining in solution and to proteins precipitated during the reaction. Both reactions are reversible, although that to precipitated protein apparently involves a stronger binding. If the latter can be correlated to the in vivo situation, it is suggested as a possible explanation of the extended retention of chlorhexidine in the mouth despite the rather rapid turnover of saliva.
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.
Effect of post‐operative use of chlorhexidine on regeneration of bifurcation defects in dogs
Authors: Bogle G. , Rathbun E. , Oliver R. , Hornbuckle C. , Egelberg J.
Published: June 2006

The daily post‐operative use of topical chlorhexidine application has been compared to daily toothbrushing. Periodontal defects were experimentally created in the bifurcations of lower premolars in dogs. The defects were treated by surgical debridment. Chlorhexidine application and toothbrushing were performed post‐operatively for six weeks on contra‐lateral pairs of teeth. The amounts of connective tissue and bone regeneration were evaluated from microscopic sections of the bifurcation areas. No difference between chlorhexidine and toothbrushing was found for the connective tissue attachment. However, significantly more bone had regenerated in the chlorhexidine treated areas than the tooth‐brushed areas.
Effect of inflammation upon human gingival oxidative metabolism
Authors: Fine A. S. , Egnor R. , Fontecchio K. , Froum S. , Scopp I. W. , Stahl S. S.
Published: June 2006

Cytochrome oxidase and NADH cytochrome c reductase activities were analyzed biochemically in gingival biopsy specimens obtained from 22 male patients (age 23–72) undergoing periodontal treatment. Histologically, 13 specimens exhibited mild inflammation, while 9 showed more severe inflammatory responses. Cytochrome oxidase activity was significantly greater in the mildly inflamed than in markedly inflamed tissue samples. NADH cytochrome c reductase activity on the other hand was not significantly altered by the increasing degree of inflammation. The possible implication of the effect of inflammation upon oxidative enzymes is discussed in relationto degenerative and proliferative changes occurring in both types of tissue.
Effect of anti‐thymocyte serum on development of gingivitis in dogs
Authors: NobrÉus Nils , Attström Rolf , Egelberg Jan
Published: June 2006

The effect of repeated injections of heterologous anti‐thymocyte globulin (ATS) on the development of gingivitis has been studied in beagle dogs. Control dogs were injected with control rabbit immunoglobulin. The immunosuppressive effect of the antiserum was evaluated from the inhibition of a delayed hypersensitivity reaction in the skin towards l‐dinitro‐2.4‐chlorobenzene (DNCB). The gingival condition was determined by measurements of crevicular leukocytes, gingival fluid, acid phosphatase activity in crevicular samples and by counts of inflammatory cells in sections of gingival biopsies. Antiserum administration, but not control rabbit IgG, abolished the hypersensitivity reaction in the skin towards DNCB. The parameters of gingival inflammation increased during the 28day experimental period, both in the experimental and in the control dogs. The results indicate that cellular immunity does not play a major role for the development of gingival inflammation in beagle dogs.
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.
Nuclear size and cytochemical changes during autolysis in free gingival autograft epithelium
Authors: Janson W. A. , Catanzaro‐Guimaráues S. A. , Passanezi E.
Published: June 2006

Karyometric and cytophtometric measurements of DNA and RNA have been evaluated in gingival graft epithelium. The study was conducted during the first 20 hours from the time of grafting when the graft epithelium undergoes a process of autolysis. Both basal cell and prickle cell layers were used. The results showed an increase in optical density for Feulgen‐DNA according to the time of grafting. At the same time pentose nucleic acid (RNA) and nuclear size showed decreasing values. It was concluded that pycnosis was the usual course of nuclear autolysis in graft epithelium. In addition gingival graft epithelium was found to be an useful model for the study of cell autolysis in vivo.
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.
Periodontal changes in distant teeth due to trauma from occlusion
Authors: Nascimento A. , Sallum A. W.
Published: June 2006

The present investigation studies the changes that occur in periodontal supporting tissues of lower canine and premolar of marmosets (Callithrix jacchus), due to experimental modification of occlusal relationships in the region of the molar. For our purposes an extracoronal arch wire of 0.7 mm diameter was fixed into occlusal perforations of the upper third premolar and first molar, on both sides. Eight male marmosets weighing from 250 to 350 grams were used. After each experimental time interval of 7, 14, 21 and 28 days two animals were sacrificed. The results clearly showed areas of tension with stretched periodontal fibers in the distal region of the canine and areas of pressure with osseous and radicular resorption in the mesial region of the first premolar. The tissue changes may be considered to result from transmission of abnormal forces through the proximal contacts of teeth associated with displacements and minor modifications in their occlusal relationships. Similar changes may occur in a tooth distant from the teeth exposed to primary excessive occlusal forces.
Elastic and oxytalan fibres in normal and inflamed dog gingivae
Authors: Soames J. V. , Davies R. M.
Published: June 2006

Consecutive sections of normal and inflamed dog gingivae were stained for elastic and oxytalan fibres using Victoria blue and aldehyde fuchisin with and without prior oxidation in potassium monopersulphate. Elastic fibres were present beneath the oral epithelium but absent beneath the junctional epithelium. Fibres stainable after oxidation were related particularly to the basement membrane regions of the oral and junctional epithelia and small blood vessels and persisted in inflammatory lesions. It is suggested that there is a different distribution of elastic and oxytalan fibres in free gingivae and that the latter may help stabilise blood vessels and the epithelial attachment under functional pressures.
Effects of local irritation and dextran sulphate administration on the periodontium of the rat
Authors: Johnson I. H.
Published: June 2006

Local irritation, provided by means of silk ligatures at the necks of mandibular first molars of rats, caused significant resorption of crestal alveolar bone. This resorption did not change significantly in extent from 27 days after placement of the ligatures. However, in rats receiving injections of dextran sulphate, there was no significant reduction in height of crestal alveolar bone of non‐ligated mandibular first molars. The injections of dextran sulphate caused the appearance of large numbers of multinucleated osteoclasts adjacent to the alveolar bone surrounding the mandibular molar teeth. There was increased irregularity of the periodontal surface of this alveolar bone. When the local and general factors were combined there was a significant increase in resorption of the crestal alveolar bone mesial to the mandibular first molars at 37 days after placement of ligatures. The systemic agent was seen to augment the effects of the local irritant beyond the time at which local irritation alone ceased to have any demonstrable effect.
Application of the H3‐proline topographic method to dental tissues
Authors: Tonna Edgar A.
Published: June 2006

Assessment is made in the present study of the applicability of the H3‐proline autoradiographic topographic method to dental and supportive parodontal tissues. Furthermore, comparisons are made of the distribution and rates of matrix production of the mineralized tissues, dentin, cementum and alveolar bone at the maxillary first molars and incisors of 5‐week‐old, short‐lived strain of BNL Swiss albino mice. The results show that tooth collagen matrix production by dentogenic and cementogenic tissues is signicantly larger than by dental or appendicular osteogenic tissues, with incisor dentin formation exceeding all surface activities evaluated to date. It is concluded that the H3‐proline topographic method is a sensitive technique offering greater refinement, and a broader spectrum of analytic possibilities than presently used technology. Integrated cellular and matrical evaluation is achieved, thus adding a new dimension to the assessment of current problems in oral biology.
Two year oral use of chlorhexidine in man
Authors: RindomSchiöstt C. , Briner W. W. , Löue H.
Published: June 2006

One group of 61 students rinsed once daily with 10 ml of a 0.2 per cent solution of chlorhexidine gluconate for two years and another group of 59 students rinsed with 10 ml of a placebo solution. Both groups were otherwise kept on the same oral hygiene programme. The number of total anaerobes, aerobes and streptococci in saliva was followed regularly before, during and after the treatment, in all for 2 years and 7 months. At the same time the number in saliva of large gram negative rods of the enteric types was followed, as was the presence of Streptococcus mutans. It is concluded that treatment with chlorhexidine resulted in a 30 to 50 per cent reduction in the number of bacteria in saliva without producing a detectable shift. A change in. the population of large gram negative rods was not observed, however, the number of students from whom Streptococcus mutans could be isolated from saliva decreased during the treatment.
Two years oral use of chlorhexidine in man
Authors: RindomSchiöstt C. , Briner W. W. , Kirkland J. J. , Löue H.
Published: June 2006

One hundred twenty students maintained similar oral hygiene procedures for two years, except that 61 students rinsed once daily with a chlorhexidine gluconate solution and the remaining 59 students with a placebo solution. The minimum inhibitory concentration (MIC) for chlorhexidine was determined for a number of salivary bacterial strains at various intervals during and after the treatment. It was concluded that chlorhexidine treatment created a selective pressure on the salivary microflora resulting in a slight change in distribution toward those organisms which were less sensitive to chlorhexidine. This change diminished after cessation of the treatment, and the distribution in the chlorhexidine group approached that of the placebotreatment group.
Orthopantomographic assessment of the width of attached gingiva
Authors: Talari A. , Ainamo J.
Published: June 2006

By revealing the mucogingival junction with Schiller's iodine solution and marking it separately at each tooth with a short piece of metal wire, attached to the tooth and gingiva with a strip of Squibb's Orahesive Dental Bandage, the location of the borderline between the attached gingiva and the free alveolar mucosa was made visible in the orthopantomogram. The orthopantomographic width of the attached gingiva was measured to the nearest millimeter by determination of the distance between the mucogingival and cementoenamel junctions along the long axis of each tooth. When the orthopantomograms of ten dentulous adults were measured twice with a one week interval, the reading error was ± 0,5 mm. When the mucogingival junctions of five dentulous adults were marked again after two months and the orthopantomographic width of the attached gingiva remeasured to the nearest millimeter, the difference between the results was ± 0,6 mm. The total deviation (± 0,7 mm) being less than the one millimeter unit of measurement, the method was judged reliable for orthopantomographic studies on gingival anatomy.
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.
Histological evaluation of the osteogenic capacity of sclera
Authors: Tdrnbull R. S. , Freeman E. , Melcher A. H.
Published: June 2006

Sclera was obtained from the eyes of New Zealand white rabbits and immediately stored at –79°C. Later, after thawing, a piece 4 mm square was implanted into each of the anterior chamber of 14 eyes and under the renal capsule of 28 kidneys of rabbits of the same strain, Allografts of skin, muscle or tendon were implanted subcapsularly in the contralateral kidneys as controls. Two animals were sacrificed postoperatively each week up to 4 weeks, 6 animals at 6 weeks, 4 each at 8 and 9 weeks and 6 at 12 weeks. Serial paraffin sections of the implants and host tissues were examined by light microscopy. Osteogenesis occurred in 7 of 12 implants of sclera implanted beneath the renal capsule at 6 and 12 weeks, but was not seen prior to 6 weeks or at 8 or 9 weeks. Osteogenesis did not occur in sclera implanted into the anterior chamber of the eye or in control implants.
The nature of root surfaces after curette, cavitron and alpha‐sonic instrumentation
Authors: Van Volkinburg James W. , Green Edward , Armitage Gary C.
Published: June 2006

Root planing instrumentation was accomplished on extracted teeth using the hand curette, the Cavitron Ultrasonic, and the Alpha‐Sonic instruments. Histologic methods were used to determine the composition of the surfaces following instrumentation. The surface roughness after instrumentation was evaluated with a profilometer and a scanning electron microscope. Hand curettes produced the surfaces with the lowest roughness values and the least apparent irregularities in the SEM photographs. In this study none of the instrumentation methods consistently removed all of the cementum.
Dictyostelium RacH Regulates Endocytic Vesicular Trafficking and is Required for Localization of Vacuolin
Authors: Somesh Baggavalli P. , Neffgen Carola , Iijima Miho , Devreotes Peter , Rivero Francisco
Published: June 2006

Dictyostelium RacH localizes predominantly to membranes of the nuclear envelope, endoplasmic recticulum and Golgi apparatus. To investigate the role of this protein, we generated knockout and overexpressor strains. RacH‐deficient cells displayed 50% reduced fluid‐phase uptake and a moderate exocytosis defect, but phagocytosis was unaffected. Detailed examination of the endocytic pathway revealed defective acidification of early endosomes and reduced secretion of acid phosphatase in the presence of sucrose. The distribution of the postlysosomal marker vacuolin was altered, with a high proportion of cells showing a diffuse vesicular pattern in contrast to the wild‐type strain, where few intensely stained vacuoles predominate. Cytokinesis, cell motility, chemotaxis and development appeared largely unaffected. In a cell‐free system, RacH stimulates actin polymerization, suggesting that this protein is involved in actin‐based trafficking of vesicular compartments. We also investigated the determinants of subcellular localization of RacH by expression of green‐fluorescent‐protein‐tagged chimeras in which the C‐terminus of RacH and the plasma‐membrane‐targeted RacG were exchanged, the insert region was deleted or the net positive charge of the hypervariable region was increased. We show that several regions of the molecule, not only the hypervariable region, determine targeting of RacH. Overexpression of mistargeted RacH mutants did not recapitulate the phenotypes of a strain overexpressing nonmutated RacH, indicating that the function of this protein is in great part related to its subcellular localization.
Ligand Valency Affects Transcytosis, Recycling and Intracellular Trafficking Mediated by the Neonatal Fc Receptor
Authors: Tesar Devin B. , Tiangco Noreen E. , Bjorkman Pamela J.
Published: June 2006

The neonatal Fc receptor (FcRn) transports IgG across epithelial cell barriers to provide maternal antibodies to offspring and serves as a protection receptor by rescuing endocytosed IgG and albumin from lysosomal degradation. Here we describe the generation of polarized Madin–Darby canine kidney (MDCK) cells expressing rat FcRn (rFcRn) to investigate the potential requirement for ligand bivalency in FcRn‐mediated transport. The rFcRn‐MDCK cells bind, internalize and bidirectionally transcytose the bivalent ligands IgG and Fc across polarized cell monolayers. However, they cannot be used to study FcRn‐mediated transport of the monovalent ligand albumin, as we observe no specific binding, internalization or transcytosis of rat albumin. To address whether ligand bivalency is required for transport, the ability of rFcRn to transcytose and recycle wild‐type Fc homodimers (wtFc; two FcRn‐binding sites) and a heterodimeric Fc (hdFc; one FcRn‐binding site) was compared. We show that ligand bivalency is not required for transcytosis or recycling, but that wtFc is transported more efficiently than hdFc, particularly at lower concentrations. We also demonstrate that hdFc and wtFc have different intracellular fates, with more hdFc than wtFc being trafficked to lysosomes and degraded, suggesting a role for avidity effects in FcRn‐mediated IgG transport.
GTP binding and hydrolysis kinetics of human septin 2
Authors: Huang Yi‐Wei , Surka Mark C. , Reynaud Denis , Pace‐Asciak Cecil , Trimble William S.
Published: June 2006

Septins are a family of conserved proteins that are essential for cytokinesis in a wide range of organisms including fungi, Drosophila and mammals. In budding yeast, where they were first discovered, they are thought to form a filamentous ring at the bridge between the mother and bud cells. What regulates the assembly and function of septins, however, has remained obscure. All septins share a highly conserved domain related to those found in small GTPases, and septins have been shown to bind and hydrolyze GTP, although the properties of this domain and the relationship between polymerization and GTP binding/hydrolysis is unclear. Here we show that human septin 2 is phosphorylated in vivo at Ser218 by casein kinase II. In addition, we show that recombinant septin 2 binds guanine nucleotides with a Kd of 0.28 µm for GTPγS and 1.75 µm for GDP. It has a slow exchange rate of 7 × 10−5 s−1 for GTPγS and 5 × 10−4 s−1 for GDP, and an apparent kcat value of 2.7 × 10−4 s−1, similar to those of the Ras superfamily of GTPases. Interestingly, the nucleotide binding affinity appears to be altered by phosphorylation at Ser218. Finally, we show that a single septin protein can form homotypic filaments in vitro, whether bound to GDP or GTP.
Molecular mass of macromolecules and subunits and the quaternary structure of hemoglobin from the microcrustaceanDaphnia magna
Authors: Lamkemeyer Tobias , Zeis Bettina , Decker Heinz , Jaenicke Elmar , Waschbüsch Dieter , Gebauer Wolfgang , Markl Jürgen , Meissner Ulrich , Rousselot Morgane , Zal Franck , Nicholson Graeme J. , Paul Rüdiger J.
Published: June 2006

The molecular masses of macromolecules and subunits of the extracellular hemoglobin from the fresh‐water crustaceanDaphnia magnawere determined by analytical ultracentrifugation, multiangle laser light scattering and electrospray ionization mass spectrometry. The hemoglobins from hypoxia‐incubated, hemoglobin‐rich and normoxia‐incubated, hemoglobin‐poorDaphnia magnawere analyzed separately. The sedimentation coefficient of the macromolecule was 17.4 ± 0.1 S, and its molecular mass was 583 kDa (hemoglobin‐rich animals) determined by AUC and 590.4 ± 11.1 kDa (hemoglobin‐rich animals) and 597.5 ± 49 kDa (hemoglobin‐poor animals), respectively, determined by multiangle laser light scattering. Measurements of the hemoglobin subunit mass of hemoglobin‐rich animals by electrospray ionization mass spectrometry revealed a significant peak at 36.482 ± 0.0015 kDa, i.e. 37.715 kDa including two heme groups. The hemoglobin subunits are modified by O‐linked glycosylation in the pre‐A segments of domains 1. No evidence for phosphorylation of hemoglobin subunits was found. The subunit migration behavior during SDS/PAGE was shown to be influenced by the buffer system used (Tris versus phosphate). The subunit mass heterogeneity found using Tris buffering can be explained by glycosylation of hemoglobin subunits. Based on molecular mass information,Daphnia magnahemoglobin is demonstrated to consist of 16 subunits. The quaternary structure of theDaphnia magnahemoglobin macromolecule was assessed by three‐dimensional reconstructions via single‐particle analysis based on negatively stained electron microscopic specimens. It turned out to be much more complex than hitherto proposed: it displays D4 symmetry with a diameter of approximately 12 nm and a height of about 8 nm.
Host‐defence peptide profiles of the skin secretions of interspecific hybrid tree frogs and their parents, female Litoria splendida and male Litoria caerulea
Authors: Pukala Tara L. , Bertozzi Terry , Donnellan Steve C. , Bowie John H. , Surinya‐Johnson Katharina H. , Liu Yanquin , Jackway Rebecca J. , Doyle Jason R. , Llewellyn Lyndon E. , Tyler Michael J.
Published: July 2006

Five healthy adult female first‐generation hybrid tree frogs were produced by interspecific breeding of closely related tree frogs Litoria splendida and L. caerulea in a cage containing large numbers of males and females of both species. Phylogenetic analysis of mitochondrial DNA sequences established the female parent to be L. splendida. The peptide profile of the hybrid frogs included the neuropeptide caerulein, four antibiotics of the caerin 1 family and several neuronal nitric oxide synthase inhibitors of the caerin 1 and 2 classes of peptides. The skin secretions of the hybrids contained some peptides common to only one parent, some produced by both parental species, and four peptides expressed by the hybrids but not the parental species.
HIGH AND VARIABLE INFLATION: FURTHER EVIDENCE ON THE FRIEDMAN HYPOTHESIS
Authors: Thornton John
Published: July 2006

This note, employing a GARCH model, finds a positive and significant relationship between the level and variability of inflation in South Africa in the period 1957:1‐2005:9. This provides evidence in support of Friedman's hypothesis that high inflation leads to more variable inflation.
Russian Contributions to the Theory of Ground‐Water Flow
Authors: DeWiest J. M. Roger
Published: July 2006

In this paper, some examples of original Russian work in the development of the theory of ground‐water flow are given. Their practical usefulness is analyzed. Comparisons with some of the more refined Western methods are made. Typical examples include seepage under hydraulic structures and well flow in leaky aquifers.
Hidden Rechargea
Authors: Feth J. H.
Published: July 2006

“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

The 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

In 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.