The influence of malocclusion on the diagnostic value of the orthopantomogram in the maxillary labial segment.

OBJECTIVE: To investigate the effect of malocclusion and incisor inclination on the diagnostic value of the orthopantomogram in the maxillary labial segment. SETTING: The Department of Orthodontics at The Royal London Hospital. MATERIAL AND METHOD: A literature review identified seven key features of an ideal radiograph of the upper labial segment. This provided the 'Gold Standard'. Four previously extracted maxillary incisors were set-up with a complementary acrylic dentition in a dry human skull. The maxillary base was modified to facilitate the movement of the upper jaw to simulate a total of nine malocclusions, based on skeletal I, II with III patterns with varying upper incisor inclination. A lateral cephalogram was taken to quantify the upper incisor inclination. An orthopantomogram (OPG), upper standard occlusal (USO) and four long-cone periapical radiographs (PA) were also taken. Each radiograph was scored against the Gold Standard. In addition, a clinical audit involving 100 new orthodontic patients was carried out to determine whether in vivo findings mirrored the in vitro results. RESULTS: The orthopantomogram provides low levels of diagnostic value in the maxillary incisor region. The diagnostic value for the skeletal I skull set-up ranged from 57 per cent for the OPG, 71 per cent for the USO and 86 per cent for the PA view. CONCLUSION: The orthopantomogram showed poor diagnostic value in relation to the upper incisor teeth. Long-cone periapicals are recommended as the supplementary view of choice in the maxillary incisor region.

Production of goats by somatic cell nuclear transfer.

In this study, we demonstrate the production of transgenic goats by nuclear transfer of fetal somatic cells. Donor karyoplasts were obtained from a primary fetal somatic cell line derived from a 40-day transgenic female fetus produced by artificial insemination of a nontransgenic adult female with semen from a transgenic male. Live offspring were produced with two nuclear transfer procedures. In one protocol, oocytes at the arrested metaphase II stage were enucleated, electrofused with donor somatic cells, and simultaneously activated. In the second protocol, activated in vivo oocytes were enucleated at the telophase II stage, electrofused with donor somatic cells, and simultaneously activated a second time to induce genome reactivation. Three healthy identical female offspring were born. Genotypic analyses confirmed that all cloned offspring were derived from the donor cell line. Analysis of the milk of one of the transgenic cloned animals showed high-level production of human antithrombin III, similar to the parental transgenic line.

The effects of fatty acids and their monoesters on the metabolic activity of dental plaque.

We examined the effects of the saturated series of fatty acids and their esters on plaque bacterial metabolism. Fatty acids with a chain length of 8-15 carbons inhibited Streptococcus mutans and dental plaque in vitro. The glycerol monoesters with a fatty acid chain of 10-14 carbons were inhibitory to a similar extent. The glycolipid (sucrose monolaurate) reduced plaque bacterial glycolysis and sucrose oxidation in a non-competitive manner but stimulated sucrose incorporation at low sucrose concentrations. The relationship between surface activity and inhibition is discussed, since this may help to explain the anti-caries effects of these compounds.

Paramolybdate anion-exchange resin, an improved catalyst for the C-1-C-2 rearrangement and 2-epimerization of aldoses.

Aqueous solutions of molybdate at 90 degrees bring about the inversion of the C-1-C-2 fragment of aldoses having four or more carbon atoms, generating thermodynamically equilibrated mixtures of the starting aldose and its 2-epimer. In some cases, notably with the aldopentoses, substantial proportions of the 3-epimers are produced, as well as 2-epimers that have not undergone inversion of the C-1-C-2 fragment. These side-reactions can be controlled by using the paramolybdate form of an anion-exchange resin (AG MP-1) together with the formate form of the same resin. The latter acts to scavenge unbound molybdate and paramolybdate anions that appear to be responsible for the side reactions.

The effects of medium chain fatty acids and fluoride on fissure caries in Wistar rats.

This work was to compare the degree of caries protection provided by fatty acids with chain lengths of 9-12 carbons and to assess the anti-caries potential of a fluoride-fatty acid mixture. Male Wistar rats were weaned at 21 days, maintained on a standard laboratory diet for 7 days and then provided with a cariogenic, 45% sucrose diet for 34 days. This regimen produced a very reproducible degree of fissure caries and the inclusion of 1% powdered potassium nonanoate or decanoate in the diet gave large and significant reductions in total and advanced lesions. Decanoate was significantly more inhibitory towards advanced lesions than was nonanoate. In contrast, 1% potassium laurate was considerably less effective under these conditions. Caries protection with a mixture of 0.25% decanoate and 76 parts/10(6) fluoride was found to be cumulative rather than synergistic. It is suggested that the optimal effect obtained with decanoate was due to a favourable combination of the surfactant and wetting properties of this molecule at the low pH values found in fissure dental plaque. It is also suggested that fluoride and decanoate acted in an independent manner to enhance remineralization of early lesions and to inhibit the acidogenic flora, respectively.

The acidogenic microbial composition of dental plaque from caries-free and caries-prone people.

Plaque samples collected from caries-free and caries-prone subjects were analysed for total bacteria, the ratio of acidogenic to total organisms and the proportions of streptococci, Streptococcus mutans and Actinomyces. The acidogenic composition of plaque reflected the dietary habits and caries status of an individual. A high acidogenic ratio was found in individuals with active lesions or recent restorations; individuals who were caries-free or had no recent lesions had a lower ratio although total organisms were similar. The ratio remained constant in sequential samples from caries-prone subjects but was increased by frequent exposure to sugar. Streptococci, Actinomyces and Strep. mutans were isolated from all samples but no consistent relationship was found between either their isolation frequency or proportions and caries status.

Project Outreach: Organizations Unified to Reach Youth.

Youths of today are forced to deal with the external pressures of alcohol and drug abuse on all levels-from the older youngsters across the street pressuring them to be "cool," to the "cute dog" enticing them with the glamour of being the original "party animal." Through today's mass communications, young people are exposed to negative, self-destructive attitudes. It is important, therefore, to expose them to a more positive influence and try to reach them through parental guidance, personal contact, and peer pressure. To achieve this, the University of Missouri's Kansas City Chapter of the American Pharmaceutical Association's Academy of Students of Pharmacy, in conjunction with the Metropolitan Kansas City Area Task Force on Alcohol and Other Drug Abuse, proposed the development of an annual drug abuse prevention program that specifically targets fifth graders in the greater Kansas City metropolitan area. A primary goal of Project Outreach (Organizations Unified to Reach Youth) is to unite drug abuse prevention programs in the greater Kansas City metropolitan area in their outreach efforts to give positive support to Kansas City's youth against alcohol and other drugs. Phase I of Project Outreach consisted of a series of programs for the parents in the community. Phase II entailed college students who spoke to fifth graders in their classrooms. These students also participated in poster and poem contents centered around drug abuse prevention. In Phase III, which featured an outstanding, motivated speaker, the sample group of 600 fifth graders in the area participated in a major event to give positive peer pressure to say no to drugs. Pertinent entertainment also was provided, and the governor of Missouri, John Ashcroft, attended the rally. In the future, each fifth grader will receive a free T-shirt as a tangible reminder of the main event. In Phase IV, to reinforce concepts presented in previous programming, the college students returned to the fifth grade classrooms to speak. Project Outreach programs are incorporated into existing drug abuse prevention programs and provide the foundation for the development of new drug abuse prevention programs in the greater Kansas City metropolitan area.

Practical applications of Stark II to hospital operations.

With the passage of the Omnibus Reconciliation Act of 1993, the Social Security Act was amended to substantially expand the Medicare self-referral prohibitions. The amended statute, commonly referred to as "Stark II," now covers Medicare and Medicaid referrals and substantially expands the list of services covered, effective January 1, 1995. This article illustrates how Stark II may apply to some of the most common financial relationships between hospitals and referring physicians.

Reduction in acid tolerance of Streptococcus downeii by fluoride and potassium laurate.

Streptococcus downeii MFe28 maintains a transmembrane pH gradient at low extracellular pH values using energy from glucose metabolism. The metabolic activity was measured in saturating glucose solutions using a pH-stat, and results were expressed as rates of titratable acid production at defined pH values. The tolerance to acid shock was studied in terms of the ability of cells to resume acid production at pH 8.0 following short-term exposure to low-pH environments. The results with control cells showed an optimum rate of acid production at pH 8.0. The activity extended to pH 4.5 with a half-maximal rate at pH 5.4. Addition of carbonyl cyanide-m-chlorophenylhydrazone, potassium laurate, or potassium fluoride inhibited acid production at lower but not at higher pH values. Inhibition by carbonyl cyanide-m-chlorophenylhydrazone and fluoride was found to be fully reversible at pH 8.0 when compared to control cells. In contrast, laurate inhibited irreversibly at pH values of 6.0 and below. The acid tolerance of S. downeii was severely compromised by laurate, and this action could be useful in dental caries control.

The conditioning role of saliva in streptococcal attachment to hydroxyapatite surfaces.

The solution properties of saliva and its role in conditioning both the substrate and the bacterial surface have been investigated with regard to the attachment of oral streptococci to hydroxyapatite surfaces. Saliva from eight subjects was used and the attachment of three organisms, Streptococcus mutans strains FA-1 (serotype b) and KPSK2 (serotype c) and S. sanguis T175-1, was studied. An adsorbed salivary layer on a hydroxyapatite surface substantially reduced the affinity of the organisms for the surface. Adsorbed saliva on the bacterial surfaces, however, tended to increase the organisms' affinity for saliva-coated apatite. The source of saliva was important in determining the extent of inhibition of attachment. The data indicated that the negatively charged and hydrophilic nature of salivary conditioning films was important in controlling bacterial adsorption to hydroxyapatite. The results also suggested that hydrophobic salivas could promote binding of the more hydrophobic bacteria known to be early colonizers of the teeth.

Carbohydrate of the human plasminogen variants. III. Structure of the O-glycosidically linked oligosaccharide unit.

The preceding two manuscripts in this issue (Hayes, M. L., and Castellino, F. J. (1979) J. Biol. Chem. 254, 8768-8771, 8772-8776) describe the isolation and characterization of glycopeptides from human plasminogen affinity chromatography variants 1 and 2. Plasminogen variant 1 contains an asparagine288-based branched carbohydrate structure, which has been established in the immediately preceding manuscript. This structure is absent in variant 2. Plasminogen variants 1 and 2 contain a threonine-based glycoconjugate. This latter structure has been established by combination of methylation data, glycosidase digestions, periodate oxidations, and Smith degradations of the beta-eliminated reduced oligosaccharides. One glycopeptide unit, isolated from both plasminogen variants 1 (1D) and 2 (2D) possessed the following structure: Sia alpha 2 yields 3Gal beta 1 yields 3GalNAc-Thr. The threonine was found to be residue 345 in the Glu-plasminogen sequence. Another glycopeptide unit was also found to be present, in lower yields in both variants 1 (1E) and 2 (2E). The structure of this unit was: Sia alpha 2 yields 3Gal beta1 yields 3GalNAc-Thr. : formula: (see text), alpha 2,6 Sia. Again Thr 345 was the glycosylated amino acid. The amino acid sequence around the glycosylated threonine was found to be NH2-Ala.Pro.Thr(CHO).Ala.Pro.Pro.Glu.

[Chemical composition (carbohydrates) of dental plaque in different areas of the mouth. 1. Preliminary results]. / Composición quimica (carbohidratos) de la placa dental de diferentes areas de la boca. 1. Resultados preliminares.

In general differences in plaque composition between anterior and posterior teeth have been reported. Dental plaque from the upper lower anterior teeth shows differences in bacterial composition and pH. Results showed that plaque from lower anterior teeth contained less alkali soluble polysaccharide per unit weight than did plaque from upper anterior teeth. However no differences in the concentration of water soluble and insoluble polysaccharide were observed. Plaque from posterior teeth did not show differences.