bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epithelial-Mesenchymal Junctional Area in an Early Stage of Odontogenesis in Macaca Fuscata
Authors: Sawada T. , Yanagisawa T. , Takuma S. 
Published: January 2017

The epithelial-mesenchymal junctional area in tooth germs of one- and three-year-old Japanese monkeys was studied with electron microscopy. The plasma membranes at the distal ends of inner enamel epithelium cells were relatively even, and were associated with basement membrane. A large number of filaments, which were 15 nm in diameter and up to 2 μm in length, were present, extending perpendicularly from the basement membrane toward the dental papilla, forming an unique fibrillar layer. The distal cytoplasm of the cell contained rather few vesicles and granules which were positive for the acid phosphatase reaction. The distal ends of differentiating ameloblasts showed irregular undulations and numerous small processes which penetrated through the basement membrane and fibrillar layer. Following an increase of the undulations, the fibrillar layer and the basement membrane were engulfed by the cells and removed from the surface of pre-dentin. Large irregular bodies, which were filled with the filaments of the disintegrating fibrillar layer, were observed frequently. The distal cytoplasm contained a large number of coated pits, coated vesicles, and acid-phosphatase-positive granules. The fibrillar layer then disappeared, being replaced by collagen fibrils in the pre-dentin, which was in the stage of early mineralization. These results indicate that the fibrillar layer is removed by the differentiating ameloblasts and degraded through an engulfing system which is formed by the cell surfaces.
Relating Developing Surface To Adult Ultrastructure in Chiropteran Enamel By Sem
Authors: Lester K.S. , Boyde A. 
Published: January 2017

The developmental basis for a newly discovered feature of adult Chiropteran (bat) enamel has been explored. Developing enamel surfaces of tooth germs of Chalinolobus gouldii have been examined after either plasma-ashing or NaOCI immersion to remove cellular material superficial to the surface. Maintenance of dimensional stability of the anorganic surface was promoted either by prior embedding in methacrylate for plasma-ashing or by subsequent critical-point-drying for wet preparation. Stereo-pair scanning electron micrographs were analyzed in a stereo-comparator and profiles reconstructed in directions parallel with the electron beam. A novel feature of the developing surface is described which accounts for the additional crystallite discontinuity line (minor boundary plane) found in the central cervical region of each horseshoe-shaped prism in what is essentially a Pattern 2 enamel. The feature is a consistent groove in the more superficial part of the developing floor wall of the Tomes' process depression, reflecting the absence of the most prominent parts of the developing enamel at the border between adjacent (Pattern 2) pits in the direction of their longitudinal alignment. The existence of a cervical floor groove was predicted from earlier observations of adult material as a result of our previously having constructed three-dimensional models utilizing the stereo-sketch approach. The present observations satisfactorily complete a conceptual cycle involving initial description of a new feature of adult bat enamel; prediction of the necessary developmental basis for it; and finally, analysis and confirmation of that developmental feature.
Light and Electron Microscopic Studies of Experimentally-Induced Pathologic Changes in the Rat Periodontal Tissue
Authors: Ijuhin N. 
Published: January 2017

Morphological changes in periodontal tissues following topical application of lipopolysaccharide (LPS) or prostaglandin E2 (PGE2) were examined in Wistar rats by light and electron microscopy. Ultrastructural demonstration of acid phosphatase and immunohistochemical localization of lysozyme in these tissues were also studied. The number of osteoclasts along the alveolar bone facing the periodontal ligament was counted. After topical application of LPS, degeneration and necrosis of the junctional epithelial cells, gingival fibroblasts, and alveolar osteoblasts were observed, as were increased bone resorption by osteoclasts and enhanced phagocytosis of collagen fibrils by fibroblasts. LPS appears to traverse easily through the junctional epithelium into the underlying gingival connective tissues. There it can cause destruction of deeper periodontal tissues by activating alveolar bone resorption and by enhancing the phagocytosis of collagen fibrils. PGE2 topically applied induced similar morphological changes. Possible participation of PGE2 in the induction of these LPS-related changes is discussed.
Neutrophil Functions in Patients with Severe Periodontal Disease
Authors: Katsuragi Y. , Matsuda N. , Nakamura M. , Murayama Y. 
Published: January 2017

Recently several investigators have reported that neutrophil functions were depressed or defective in localized and generalized juvenile periodontitis. It has also been shown that patients with adult periodontitis exhibit no such abnormalities. Concerning rapidly progressing periodontitis, only a few reports have been provided. The purpose of the present study was to compare various neutrophil functions in patients with rapidly progressing periodontitis (RPP), generalized adult periodontitis (AP), and in periodontally healthy or control subjects. Neutrophils and monocytes were obtained from heparinized peripheral blood of 13 RPP, 16 AP, and 18 control subjects. Cells were isolated by Percoll® discontinuous density gradient centrifugation. Neutrophil phagocytosis was examined by use of FITC-labeled bacteria, and the number of EA rosette-forming cells was determined. Random migration and chemotaxis of neutrophils and monocytes were evaluated with the Boyden chamber. In addition, opsonizing activity of plasma, effects of plasma on phagocytosis and chemotaxis, and lysosomal enzyme secretion were also determined. Neutrophil phagocytosis was markedly depressed in RPP compared with AP and those with normal periodontal tissue. The number of phagocytizing neutrophils was decreased and seemed to be correlated with the number of EA rosette-forming cells. Random migration and chemotaxis of neutrophils and monocytes were not significantly different among these three study groups. No differences in other neutrophil functions could be found. From these results, it was clear that neutrophil phagocytosis in RPP patients was depressed. These results suggest that neutrophil abnormalities may lead to decreased resistance to periodontal infections in adults with rapidly progressing forms of periodontal disease.
The Function of Gingival Lymphocytes on the Establishment of Human Periodontitis
Authors: Okada H. , Shimabukuro Y. , Kassai Y. , Ito H. , Matsuo T. , Ebisu S. , Harada Y. 
Published: January 2017

Human periodontitis has been confirmed to be an IgG plasma cell-rich lesion. However, we also detected many T cells, both CD4-positive and CD8-positive cells, in periodontal lesions. Some of these T cells expressed HLA-DR (la-like) antigen on their surfaces, and the proportion of HLA-DR+ cells was approximately equal in both CD4+ and CD8+ cell populations (Okada et al., 1983, 1984). Consequently, both helper and suppressor T cells were believed to participate in the establishment of periodontal lesions. On the other hand, B cells were thought to be activated polyclonally in periodontal lesions, because a variety of periodontal florae possessed polyclonal B-cell-activating activity. We demonstrated that Actinomyces viscosus T14V stimulated mouse spleen B cells polyclonally and induced many IgM-producing cells but few IgG-producing cells. Moreover, IgG-producing cells were differentiated from only surface IgG-positive B cells but not from surface IgG-negative B cells-namely, surface IgM- or IgA-positive B cells (Harada et al., 1988). These results suggested that memory B cells, which had already been primed with appropriate antigens, might migrate into periodontal lesions, and then be activated polyclonally and develop into IgG-producing cells. The periodontal lesion could, therefore, be induced by the interactions of immunoregulatory mechanisms of T cells and polyclonal B cell activity of periodontal florae. In fact, L3T4-positive T cells (helper-inducer T cells) enhanced IgG synthesis of mouse spleen B cells which had been activated with T-independent B cell activators such as LPS and A. viscosus preparations (Okada et al., 1987; Ito et al., 1988). We hypothesized from the above results that autoreactive T cells recognized the increasing self-MHC class II(Ia) antigen on B cells which had been activated with polyclonal B cell activators, and then produced soluble factors, which could enhance IgG synthesis of these B cells. Autoreactive T cells as well as PBAs, thus, may play an important role in the establishment of the IgG plasma cell-rich periodontal lesion.
Effects of Culture Supernatants of Leukocytes from Periodontal Patients on Monocyte-Mediated Hydroxyapatite Resorption
Authors: Marumoto Y. , Sato I. , Ikeda K. 
Published: January 2017

In this study, the effects of culture supernatants on various activities of the monocyte, as a bone-resorbing cell, were compared between peripheral blood leukocyte (PBL) cultures from patients with periodontal disease and those from subjects with a clinically healthy periodontium. We have reported that normal human monocytes in vitro induce the release of calcium from synthetic hydroxyapatite particles and that the activity is enhanced by supernatants from cultures of stimulated or non-stimulated peripheral blood leukocytes. Monocytes from both patients and healthy subjects induced the release of calcium from hydroxyapatite particles (HA) to an equal degree. This activity of monocytes from healthy subjects showed a statistically significant increase by addition of supernatants from stimulated or unstimulated cultures of peripheral blood leukocytes from periodontitis patients. This increase was greater than that seen with supernatants from cells of healthy controls. The Nitro Blue Tetrazolium reduction activity and [3H]-thymidine incorporation of monocytes were also increased by addition of the supernatants from leukocyte cultures from either patients or healthy controls, but no significant difference was noted in the increase. These results suggest that the HA-resorbing activity of monocytes was enhanced by factors from cultured leukocytes. Furthermore, these studies showed that production of these factors by peripheral mononuclear cells from patients with periodontal disease was greater than that seen with cells from normal subjects.
The Concentration of Salivary Steroid Hormones and the Prevalence of Gingivitis at Puberty
Authors: Morishita M. , Aoyama H. , Tokumoto K. , Iwamoto Y. 
Published: January 2017

Gingival conditions of 1323 junior high schoolchildren aged 12-15 were examined, and 132 children who had either healthy gingivae or severe gingivitis were called to the clinic. More precise examination of gingivitis was performed by assessment of Jackson's gingivitis index (G.I.), probing depth (P.D.), and bleeding on probing. Whole saliva was collected, and the salivary concentrations of estradiol, progesterone, and testosterone were determined by radioimmunoassay. Subgingival bacterial plaque was sampled from 36 children, and total bacterial counts and morphological differentiation were performed under a phase-contrast microscope. For statistical analysis, both males and females were divided into two groups according to the concentration of each sex hormone and subgrouped by the results of clinical examinations. Chi-square analysis using 2-by-2 tables was performed to determine the relation between salivary steroid hormone levels and gingival inflammation. The results suggest that unbalanced secretion of certain hormones might be one of the factors promoting gingivitis at puberty.
Periodontal Treatment by Local Drug Delivery Using Resorbable Base Material
Authors: Noguchi T. , Fukuda M. , Ishikawa I. 
Published: January 2017

The effects of local drug delivery to the subgingival plaque flora using resorbable base material were evaluated by the study of microbial composition in periodontal pockets and clinical manifestations of disease. In vitro, the drug used in this study was released within 24 hr from the hydroxypropylcellulose (HPC) strips. In vivo release of the drug from strips was also measured in nine patients who had, contralaterally, deep pockets of more than 5 mm. A tetracycline (TC)-containing HPC strip was inserted in one pocket, and a blank strip without TC was inserted in the other pocket. The amount of TC in the gingival crevicular fluid (GCF) 24 hr after insertion of the strip was significantly higher than that of the control. Ten subjects, who had at least three pockets greater than 4 mm in depth, were selected from 50 volunteers after an initial examination. HPC strips containing TC, chlorhexidine (CH), and control (base material) were inserted into each pocket three times a week. Clinical and microbiological changes ascertained by darkfield microscopy were monitored over three weeks. Reduction of both probing depth and bleeding-on-probing was observed only in the pockets in which TC was administered. Changes of microbial composition of subgingival plaque were, however, found in both TC- and CH-treated pockets. The percentages of spirochetes and motile rods were remarkably reduced in these pockets.
Fluoride and Enamel Defects
Authors: Horowitz H.S. 
Published: January 2017

The concentration of fluoride in drinking water is the major determinant of the prevalence and severity of dental fluorosis in a community. Fluorosis is more prevalent and discernible in permanent teeth than in primary teeth; the intensity can range from barely perceptible, whitish striations in enamel to confluent pitting and dark staining. The traditional belief is that fluorosis is produced only during the secretory stages of ameloblastic activity. Some recent reports suggest that the maturation stages of enamel development are as important as or even more important than the secretory stages as the time when fluorosis can be produced. The question of timing remains unresolved. Many questions also remain about general and individual physiologic variations in relation to susceptibility to dental fluorosis. Good criteria for differential diagnosis exist to distinguish dental fluorosis from non-fluoride enamel opacities. An increasing number of reports indicates that the prevalence of fluorosis may be increasing among children in fluoridated and non-fluoridated communities. Reasons for the increases may relate to misuse of dietary fluoride supplements, ingestion of fluoride toothpastes, or increasing amounts of fluoride in foods or the atmosphere. The intensity of the increased fluorosis is in the milder categories and is not generally unsightly. It should be recognized that a small amount of fluorosis may be an alternative to a greater prevalence of dental caries, a disease that may produce cosmetic problems and sequelae worse than those produced by fluorosis.
Dental Enamel Hypoplasias in Prehistoric Populations
Authors: Goodman A.H. 
Published: January 2017

Recent years have witnessed an impressive increase in research on enamel hypoplasias in archaeological populations. By reviewing a series of studies of enamel hypoplasias at Dickson Mounds, Illinois, North America (950-1300 A.D.), a prehistoric site involved in the transition from gathering-hunting to agriculture, this paper provides an illustration of this type of research. The location of linear hypoplasias on labial tooth surfaces of 111 adults was studied with a thin-tipped caliper, and this location was converted to an age at development. Most defects developed between two and four years of developmental age. Hypoplasias increased in prevalence from 45% in the pre-agriculture group to 80% in the agricultural group (p < 0.01). The transition to agriculture occurred at a cost to infant and childhood health. Defects are associated with decreased longevity. Individuals with defects have a life expectancy of nearly ten years fewer than those without defects, suggesting that the development of a defect marks a significant and lasting health event. Enamel hypoplasias occur most frequently on anterior teeth, polar teeth in developmental fields, and the middle developmental thirds of teeth. Analysis of these data suggests that enamel may be differentially susceptible to growth disruption and that susceptibility varies both within and among teeth. The study of enamel defects at Dickson provides insights into the health and nutritional consequences of the economic change from hunting and gathering to agriculture. More generally, with the availability of teeth from genetically homogeneous populations, studies of enamel hypoplasias in prehistory should provide a useful complement to research on this condition in contemporary peoples.
Degradability of Dental Ceramics
Authors: Anusavice K.J. 
Published: January 2017

The degradation of dental ceramics generally occurs because of mechanical forces or chemical attack. The possible physiological side-effects of ceramics are their tendency to abrade opposing dental structures, the emission of radiation from radioactive components, the roughening of their surfaces by chemical attack with a corresponding increase in plaque retention, and the release of potentially unsafe concentrations of elements as a result of abrasion and dissolution. The chemical durability of dental ceramics is excellent. With the exception of the excessive exposure to acidulated fluoride, ammonium bifluoride, or hydrofluoric acid, there is little risk of surface degradation of virtually all current dental ceramics. Extensive exposure to acidulated fluoride is a possible problem for individuals with head and/or neck cancer who have received large doses of radiation. Such fluoride treatment is necessary to minimize tooth demineralization when saliva flow rates have been reduced because of radiation exposure to salivary glands. Porcelain surface stains are also lost occasionally when abraded by prophylaxis pastes and/or acidulated fluoride. In each case, the solutes are usually not ingested. Further research that uses standardized testing procedures is needed on the chemical durability of dental ceramics. Accelerated durability tests are desirable to minimize the time required for such measurements. The influence of chemical durability on surface roughness and the subsequent effect of roughness on wear of the ceramic restorations as well as of opposing structures should also be explored on a standardized basis.
Ordinary women and shapes of knowledge: perspectives on the context of STD and AIDS
Authors: Wallman Sandra 
Published: January 2017

In Europe, as well as in Africa, HIV-related studies of women tend to focus on narrowly-defined professional, behavioral, or reproductive categories. The research population for this study of symptom definition and treatment-seeking among women in Kampala, Uganda, was defined only by residence in one low-income “parish” of that city. Its practical justification is the association of STD and HIV: effective treatment of (curable) STD can reduce the risk of HIV infection. STD and AIDS, however prevalent, are never the only things ordinary people have to worry about; their capacity for preventing, managing, or explaining infection is dependent on the range of other things that may be happening in their lives. An analyst-observer's view is by contrast narrower, and the context of scientific understanding is different. This paper sets out an approach that stresses the differences between “real people” knowledge and scientific or professional knowledge about the problem, and between practical and symbolic levels of context. In the light of this approach the seeming chaos of what these women do—or do not do—about getting treatment for STD becomes intelligible. I conclude that the contingency of context and the gap between “real” and “scientific” understanding combine to account for the normal inconsistency of social data, and that the proper use of a context perspective renders these data intelligible.
Health Management/Leadership of Small Island Developing States of the English-speaking Caribbean
Authors: Greaves Damian E. 
Published: January 2017

Over the last decade, small island states of the English-speaking Caribbean have been embarking on health sector reform initiatives in order to strengthen the quality of the delivery of health services. The wave of health sector reform measures has not placed emphasis on the management/leadership of health care delivery systems which tend to be generally weak. This in turn affects the improved delivery of quality services and superior quality health care. Management and leadership are understood as the capacity to guide the health sector’s institutions and to mobilize stakeholders, organizations and social groups. The general idea is that there are a number of challenges that affect health management of the small island developing states (SIDS) and the efficient organization of these dynamic, complex health systems. These challenges are tied to the unique cultural, organizational and political characteristics of island states. In all of this, the competencies and unique roles required of senior managers/leaders in a SIDS setting are called to question. Objective This article provides an overview of the management/leadership of health systems in SIDS of the English- speaking Caribbean region. It highlights the weaknesses and challenges of management and organization of these systems which in turn impact the desired outcome of promotion of quality delivery of health care. It also examines roles of senior health managers/leaders in the economic, social, political and cultural context of SIDS. The article strongly advocates the need for in-depth study of the challenges that bedevil efficient and effective management of health systems in the region as well as the processes that constrain or facilitate the activities of senior health managers. It also highlights the need for an investigation into competencies that health managers/leaders demonstrate and perceive that they need in effectively managing these health care delivery systems. Method I wrote this article based on literature review, experience as minister for health of the Ministry of Health of Saint Lucia—one of the island states of the English-speaking Caribbean—and in-depth, semistructured interviews with senior health managers/leaders across the region.
Using Problem-Solving Therapy to Reduce Depressive Symptom Severity Among Older Adult Methadone Clients
Authors: Rosen Daniel , Engel Rafael , McCall Janice , Greenhouse Joel 
Published: January 2017

Objective: Treatment of older adults in methadone maintenance treatment (MMT) with comorbid mood disorders presents many challenges. The goal of this randomized controlled trial was to assess the combined effect of problem-solving therapy (PST) with treatment as usual (TAU) compared to TAU alone on decreasing depressive symptoms in opioid-addicted older adults in MMT. Methods: Sixty-four methadone clinic attendees, at least 50 years old, with moderate depressive symptom were randomized to PST + TAU ( n = 29) or TAU ( n = 35). PST is an intervention for depressed older adults with a focus on teaching problem-solving skills. Results: There was not a statistically significant difference in depression scores between the two treatment groups. However, there is evidence for a clinically meaningful decrease in symptoms in the PST + TAU group 7 months post treatment (Cohen’s d = .57) Conclusion: Clinical implications of PST + TAU in comparison to TAU on depressive symptom seemed to have lasting benefits at 6-month post treatment.