Further statistics in dentistry: Part 1: Research designs 1

This new series of articles is designed to supplement, rather than replace, the material contained in the earlier series on statistics in dentistry published in the British Dental Journal and subsequently made available in book form.(1) With the increasing availability of calculators, personal computers and computer statistical software packages, the need for details of the 'nuts and bolts' of statistical theory has diminished, but the need for an understanding of how and when such theory should be applied, and how studies should be designed to make best use of it, has probably increased. It is with these thoughts in mind that this new series is being offered.     

Identity of 1:2:1 and 2:4:2 subgingival spirochetes by DNA hybridization

A group of 1:2:1 and 2:4:2 subgingival spirochetes, well characterized by transmission electron microscopy, biochemical tests, cellular fatty acid and carbohydrate analyses, and ribotyping, was recently suggested to represent new treponemal species. The present study used DNA hybridization to examine this possibility. When DNA of a representative strain (no. 16) of the 8 1:2:1 spirochetes examined was labeled by iodination, it showed, after SI nuclease treatment, from 58 to 104% (average 76%) homology with DNA from the 1:2:1 spirochetes. 94% homology with DNA from the type strain of Treponema socranskii and of T. socranskii subsp. socranskii , i.e., ATCC 35536T, and 62% homology with DNA from T. socranskii subsp. buccale , strain ATCC 35534^T. Similarly treated DNA from a representative strain (no. 3) of 8 2:4:2 spirochetes exhibited from 90 to 105% (average 97%) homology with DNA from the 2:4:2 spirochetes, and 85% and 87% homology, respectively, with DNA from Treponema denticola strains ATCC 33520 and FDC T1. There was a negligible degree of homology between the 1:2:1 and 2:4:2 spirochetes. Thus, all the 2:4:2 spirochetes belonged to T. denticola . 1:2:1 strains with DNA homology levels >70% (5 strains) belonged to T. socranskii or T. socranskii subsp. socranskii , while those with homology levels from 58 to 63% (3 strains) most likely belonged to other subspecies of T. socranskii .     

Teil 1: Die EU-Kommission

Der Freie Zahnarzt - Motor der europäischen Entwicklung. Die Europäische Kommission ist das politisch unabhängige Exekutivorgan der EU. Ihre Kompetenzen sind sowohl einmalig als auch...     

Toothache tales: Part 1

This selection of literary extracts deals with the subject of toothache from the point of view of the sufferer. Circumstances, effects and remedies, orthodox and otherwise, are described.     

累及乳牙列的单纯性多数牙先天缺失1例

报道1例累及乳牙列的单纯性多数牙先天缺失,且个别牙非左右对称缺失,并有遗传倾向的病例。     

The pharmacokinetics and cardiovascular effects of high-dose articaine with 1:100,000 and 1:200,000 epinephrine

OBJECTIVES: The authors conducted a randomized, double-blind, two-way crossover clinical trial to compare the pharmacokinetics and cardiovascular effects of 11.9 milliliters of 4 percent articaine hydrochloride (HCl) plus 1:100,000 epinephrine (A100) with those of 11.9 mL of 4 percent articaine HCl plus 1:200,000 epinephrine (A200). METHODS: During two testing sessions, the authors administered injections of A100 and A200 over a seven-minute period (in one-cartridge doses unless otherwise noted): maxillary right first molar infiltration, maxillary left first molar infiltration, maxillary right first premolar infiltration, maxillary left first premolar infiltration, right inferior alveolar injection, left inferior alveolar injection, right long buccal infiltration (one-half cartridge) and left long buccal infiltration (one-half cartridge). They analyzed venous blood samples for articaine levels. They used noninvasive acoustic tonometry to measure a variety of cardiovascular parameters over a two-hour period. RESULTS: Plasma concentration curves of articaine over time were similar for both solutions, with peak concentrations and times to maximum concentration being 2,037 nanograms per milliliter and 22 minutes for A100 and 2,145 ng/mL and 22 minutes for A200. At the 10-minute point, the mean systolic blood pressure and heart rate were significantly elevated (P < .05) with A100 versus A200. CONCLUSIONS: Maximum dose recommendations for the A100 solution also can be applied to the A200 solution. A200 produces less cardiovascular stimulation than does A100. CLINICAL IMPLICATIONS: A200 is as safe as A100, and may be preferable to A100 in patients with cardiovascular disease and in those taking drugs that reportedly enhance the systemic effects of epinephrine.     

CO oxidation on stepped Rh[n(1 1 1) × (1 1 1)] single crystal electrodes: a chronoamperometric study

The CO electro-oxidation reaction has been studied on Rh[n(1 1 1) × (1 1 1)]-type electrodes in 0.5 M H₂SO₄ using chronoamperometry. The transients recorded on Rh(1 1 1), Rh(5 5 4), Rh(5 5 3) and Rh(3 3 1) are characterized by a current plateau, visible directly after charging of the double layer, followed by a main oxidation feature, which consists of two peaks, a pre-peak and a main peak. The current density in the plateau region is nearly constant over time and, thus, is of (quasi) zeroth order in CO coverage. A plot of log(j_plateau) vs. E_final gives a linear relationship with a slope of ca. 45 mV dec^?1, suggesting a second electron transfer as the rate determining step. Analogously to platinum, the current density plateau was ascribed to a Langmuir–Hinshelwood type reaction between CO_ads and OH_ads with no effective freeing of sites for OH adsorption due to relaxation of the CO adlayer. The presence of two peaks, rather than one, in the main oxidation feature can be explained by assuming a low surface mobility of CO and high oxidizability of rhodium surfaces. Indeed, dual step chronoamperometry shows that the mobility of CO on rhodium surfaces in aqueous media is very low. Since rhodium surfaces are known to oxidize readily, the pre-peak and main peak can be ascribed to CO reacting with OH, which adsorbs fast at the steps and more slowly at terrace sites. Since the geometry of the steps is nearly the same on each surface, the pre-peak appears structure insensitive, while the main peak shifts considerably with the step density. Introducing randomly distributed crystalline defects by cycling the electrodes repeatedly up to the surface oxidation region prior to each potential step experiment, results in a negative shift of the main peak, while the position of the pre-peak remains fixed. From the data presented, we conclude that the reaction nucleates at the steps and grows in the direction of the terraces.     

Salivary detection of H1N1 virus: a clinical feasibility investigation

The fast and efficient transportation among continents will continue to play a role in the spread of airborne pandemics. The objective of this study was to detect H1N1 virus in the saliva of individuals who visited the emergency department and were diagnosed as having H1N1 influenza. Nasopharyngeal swabs and saliva samples from those who presented to the emergency department with flu-like symptoms were sent to the laboratory. RNA was extracted from both samples. Real-time RT-PCR tests were performed, and the saliva and nasopharyngeal swab tests were compared. Samples were drawn from 26 individuals. A positive nasopharyngeal swab test and salivary test was found in 14 persons, and negative tests were found in 12 persons. Saliva sampling for H1N1 has excellent predictive value, is highly accurate and reliable, and is more convenient than the nasopharyngeal swab. Clinical trial with the Helsinki Committee at Rambam Health Care Campus, registration number 036309-RMB.     

头颈部横纹肌肉瘤11例临床病理学分析

目的：探讨头颈部横纹肌肉瘤（rhabdomyosarcoma,RMS）的临床病理学特征、免疫表型及鉴别诊断。方法：回顾性分析11例头颈部 RMS 的临床资料、病理形态和免疫组织化学标记结果。结果：11例患者中男性8例,女性3例。年龄2～51岁,中位年龄25岁。主要表现为头颈部痛性或无痛性肿块,组织学分型：胚胎型8例,腺泡型3例。免疫组织化学结果显示瘤细胞均表达结蛋白、波形蛋白;肌调节蛋白（MyoD1）、生肌蛋白（myogenin）的阳性率分别为45％、55％;2例表达突触素,所有病例均不表达广谱角蛋白、白细胞共同抗原及 S-100。术后随访6个月～5年,其中2例死亡,4例复发,2例转移。结论：头颈部横纹肌肉瘤罕见,临床症状不典型,病理诊断需结合组织学形态及免疫表型。