Molecular differentiation of Pantoea stewartii subsp. indologenes from subspecies stewartii and identification of new isolates from maize seeds

AIMS

Assays to detect Pantoea stewartii from maize seeds should include differentiation of P. stewartii subsp. stewartii and P. stewartii subsp. indologenes.

METHODS AND RESULTS

Previously published PCR primers for the identification of P. stewartii subsp. stewartii amplified signals from both subspecies using both conventional and quantitative PCR. In MALDI-TOF mass spectroscopy analysis with the Biotyper software (Bruker), subspecies stewartii and indologenes produced identical score values. Analysis against the Biotyper database produced similar score values for both subspecies. From the subtyping methods provided by the Biotyper software, only composite correlation indexing (CCI) separated both groups. By alignment of 16S rRNA sequences, no subspecies distinction was possible. To develop new techniques for the separation of these subspecies, the partial sequences of several housekeeping genes were compared. The type strains of the two subspecies showed characteristic single-nucleotide polymorphisms (SNPs) in the genes galE, glmS and recA. Other reference strains of P. stewartii subsp. stewartii followed the same nucleotide pattern, whereas known P. stewartii subsp. indologenes strains were different. Based on single-nucleotide polymorphisms in galE and recA, PCR primers were created to separate the subspecies by stepdown PCR analysis. Two putative P. stewartii strains were isolated from imported maize seeds. They were not virulent on maize seedlings, were positive in the indole assay with Kovacs reagent and identified as P. stewartii subsp. indologenes. The subspecies-specific PCR primers confirmed they were subspecies indologenes.

CONCLUSIONS

By stepdown PCR, P. stewartii subsp. indologenes can be differentiated from P. stewartii subsp. stewartii.

SIGNIFICANCE AND IMPACT OF THE STUDY

A possible detection of P. stewartii subsp. stewartii, the causative agent of Stewart's wilt of maize, in plant material by immunological or molecular assays must exclude contamination with P. stewartii subsp. indologenes, which would create false positives in seed tests and affect quarantine measurements.

Plaque removal efficacy of two rotating/oscillating electric toothbrushes

This study compared the plaque removal efficacy of the Philips Jordan HP510 and Braun Oral-B D9 electric toothbrushes in two clinical trials. In Trial I, a single-blind randomized split-mouth study, 24 subjects received an oral prophylaxis and abstained from all oral hygiene procedures for 24 hours before each quadrant was professionally brushed for 30 seconds. Plaque was scored before and after brushing using the Turesky-modified Quigley and Hein index (Q&H) and the approximal plaque index (API). Trial II was a two-week, single-blind balanced cross-over study comprising 54 subjects. At baseline, the subjects received an oral prophylaxis and instruction in the use of the assigned brush. Two weeks later, they returned to the clinic with 24-hour plaque accumulation. Plaque (Q&H, API) was scored before and after supervised brushing (30 sec/quadrant). After a prophylaxis, the subjects received the other brush with instructions on use, and the procedure was repeated. In Trial I, plaque was removed almost equally well by both brushes, with the HP510 and the D9 reducing Q&H from 1.46 and 1.47 (baseline) to 0.53 and 0.58, respectively, on average over all teeth. For the premolars and molars in particular, use of the HP510 resulted in statistically significantly lower Q&H scores than the D9 (0.70 vs. 0.81). In Trial II, the HP510 resulted in significantly better plaque scores than the D9 on Q&H (0.55 vs. 0.67) and API (23% vs. 28%) for all teeth. The buccal surfaces contributed the largest difference in Q&H. Statistically significant differences were also found in scores of the posterior teeth for Q&H (0.75 vs. 0.86) and API (31% vs. 38%). In conclusion, both rotating/oscillating electric toothbrushes were highly effective in plaque removal. The HP510 removed more plaque than the D9, particularly from the posterior teeth. It appeared that the smaller height and the Active Tip of HP510's brush head could have resulted in better posterior and approximal access.

Plaque removal efficacy of an electric and a manual toothbrush with additional interdental tufts

This clinical study compares the plaque removal efficacy of the Philips/Jordan 2-Action Plaque Remover electric toothbrush with that of the Oral-B 35 Advantage manual toothbrush. In this single-blind randomized split-mouth study, subjects brushed under supervision after having abstained from all oral hygiene for 24 hours. Plaque scored after brushing was used to compare the efficacy of the toothbrushes. Both toothbrushes have special tufts to promote interdental cleaning. It was found that these tufts improve interdental cleaning. Overall, the Philips/Jordan brush removed significantly more plaque than the Oral-B manual brush.

A comparison of plaque removal effectiveness of an electric versus a manual toothbrush in children

The purpose of this study was to test the plaque-removing efficacy of an electric brush (Philips HP550) in comparison with a manual brush (Butler Gum 111) in five- to ten-year-old uninstructed children. The sample included twenty-three children who were divided into two groups, each group brushing for four weeks with the assigned brush at home. After this period children were asked to brush for two minutes in a dental clinic. Plaque was scored according to the Turesky modified Quigley and Hein Index before and after brushing. Analysis shows that plaque reduction with the electric brush is significantly better than with the manual brush: 46 percent versus 25 percent reduction, respectively. Results are most marked for the lingual posterior areas. Results further indicate that using an electric brush, plaque is reduced more evenly over the dentition. Participants without previous experience with powered toothbrushes showed no problem in adapting to the electric brush.

Effect of pore topology on the remineralization rate of surface-softened enamel and synthetic hydroxyapatite: an experimental comparison and mathematical model

Experiments with surface-softened synthetic hydroxyapatite show similar remineralization rates as surface-softened human enamel. The mineral gain with respect to time relates to parameters governing the precipitation of mineral in the specimens. A mathematical model regarding the mineral precipitation on the pore surface is fitted to the experimental values. We obtained comparable precipitation rates for apatite and tooth enamel. The geometry of the pores, however, proved to be different: a mostly tube-like pore structure must be attributed to demineralized enamel, while the synthetic hydroxyapatite specimens remineralize like a ramified, crack-like microstructure of pores.

Increased interleukin-1 beta (IL-1 beta) concentration in gingival tissue from periodontitis patients

Human gingival tissues from periodontitis patients were found to contain from 126 fg/mg to 2161 fg/mg interleukin-1 beta as determined by a sensitive enzyme linked immunoassay. No IL-1 beta could be found in normal gingival tissue. This finding may have important consequences relevant to connective tissue destruction and episodes of alveolar bone resorption characteristic of chronic periodontitis.

[Enhancement of bite-wing radiographs by digital image processing]

Extracted premolars with an initial approximal caries were subjected to radiographic and histological examination. Radiographs were taken with the rectangular technique as used for bite-wing radiographs. Digital image processing was found to enhance the image information so that the border of caries lesions as well as histological structures, Retzius lines and Hunter Schreger stripes, within the body of the lesions were well defined. This helps to distinguish initial caries from depressions in the tooth surface.

[Ultrasound-guided fine-needle puncture of the thyroid]

If properly performed, modern high-resolution real-time ultrasonography will disclose subtle differences in the texture of thyroid tissue and thereby enable the examiner to suggest a diagnosis. Nevertheless, there is often a need for a more specific diagnosis of solid or semisolid thyroid lesions - especially when the lesion might be malignant. Ultrasonically guided fine-needle aspiration biopsy (UG-FNB) allows a final cytological and/or histological diagnosis to be made in patients with benign or malignant space-occupying growths even if they are small. In its simplest form, thyroid nodules (diameter greater than 1.5 cm) with a uniform sonographic texture are punctured blind after determination of the site and size of the lesion on the basis of ultrasonic imaging. When the lesion is small and deeply situated (diameter less than or equal to 1.5 cm), this method will not be sufficiently accurate and more precise needle guidance is mandatory. In ultrasonically guided fine-needle puncture, the idea is to place the tip of an appropriate needle safely and accurately in the suspect lesion, so that representative specimens of solid tissue or fluid can be obtained and technical failures reduced. The main indication for biopsy of the thyroid gland is to differentiate between benign and malignant tumors. To compare the accuracy of conventional puncture techniques and ultrasonically guided puncture methods, 835 patients with benign or malignant space-occupying growth (even the small ones) were examined simultaneously with conventional and ultrasonically guided fine-needle aspiration biopsy over a period of 3 years (prospectively). Our results showed a significant difference in the sensitivity between conventional puncture without sonographic guidance and ultrasonically guided puncture techniques performed on patients with small and very small lesions (phi less than 2 cm). The size, macroscopic structure, and topographic-anatomical localization of the lesions were found to influence the diagnostic accuracy of the puncture techniques. UG-FNB is an excellent, effective, safe and painless method of treating uncomplicated thyroid cysts; it should be considered an alternative to surgery, if there are no clinical and cytological findings indicating malignancy and no severe space-occupying complications. Since the tip of the needle can be visualized on the scan, the needle may be advanced or withdrawn during aspiration so it is possible to empty the cyst completely. The use of ultrasound in the follow-up of patients with thyroid cyst puncture is mandatory to evaluate the results. Surgical therapy should be reserved for large cysts causing space-occupying complications.

[Digital image processing in the radiographic diagnosis of caries]

Used with x-ray films of entire teeth, digital image processing renders visible not only the contours of initial carious lesions but even histological enamel structures. In over 90% of those cases in which the lesions were deeper than one third of the enamel thickness at least the Hunter-Schreger lines were visible. This improvement in the informative value of x-ray images facilitates the therapeutic decision making process.

Enhancement of in-vivo remineralization of approximal initial caries in man by an organic and inorganic remineralization agent

Changes of mineral content in the approximal enamel of the teeth were determined in situ with quantitative bite-wing radiography. Geometric coincidence of the base line and control radiographs was achieved with an optical adjusting device for the X-ray tube and for exact re-location of the film to the dentition. Radiographs were evaluated with digital image-processing. To five subjects, inorganic remineralization solution containing Ca, Sr, phosphate and tartrate was applied twice a day and to another 6 persons a solution containing aminofluoride (Elmex Fluid, Gaba Int.) every third day: both for 3 weeks. There was no net mineral uptake in the 15 lesions of the inorganic group but a marked increase of mineral in the 13 lesions of the other group. Discrepancy with findings of other workers may be due to the geometry of the interdental space with long diffusion distances in the dental plaque.

A method for radiographic longitudinal study of mineral content during in-vitro demineralization and remineralization of human tooth enamel

The combination of X-ray-radiography with digital image processing described provides a tool for longitudinal studies of de- and remineralization of dental enamel. The mineral loss and uptake can be observed in the same specimen.

[Metastatic differentiated thyroid cancer. Diagnostic accuracy of thyroglobulin-RIA in comparison with 131I-whole body scintigraphy]

In a retrospective analysis in patients with differentiated thyroid carcinoma, the diagnostic validities of 131I whole-body scans and radioimmunologic determinations of thyroglobulin (hTg) are compared with special regard to late metastases. Metastases were found in 83 out of 311 patients with differentiated thyroid carcinoma. In two thirds of the cases, these were primary metastases while in the remaining third of the cases, metastases developed in later follow-up with a mean time of latency of 3.3 years. While about 70% of the early metastases could bei detected by 131I scintigraphy, this percentage amounted to only 40% in late metastases. With a diagnostic sensitivity of 90%, hTg-RIA was clearly superior in the detection of early as well as of late metastases. hTg was measurable, however, only in iatrogenous hypothyroidism in 4 out of 49 cases. Based on these results and an analysis of the literature, a program for follow-up of differentiated thyroid carcinoma is proposed. The hTg-RIA is thereby used as an alternative to 131I scintigraphy in the late phase of follow-up after complete ablation of any thyroid tissue.

[Direct and indirect parameters for free thyroxine. II. Diagnostic accuracy in disorders of thyroid function and binding protein anomalies]

Part II of the study concerning the clinical applicability of direct and indirect parameters for free thyroxine evaluates the diagnostic accuracy of the FT4-RIAs ImmoPhase, GammaCoat, Liquisol, Amerlex and LisoPhase in relation to FT4 index and T4/TBG ratio. This comparison of methods is done on a thoroughly classified collection (n = 640) of patients with normal and impaired thyroid function including patients with binding protein anomalies (pregnancy, estrogen-medication, phenytoin therapy, renal protein loss). FT4 normal ranges of a given kit harmonize well with data of the manufacturers and of the literature. On the other hand, the normal ranges of the various kits are not comparable. The differentiation of euthyroidism from hyper- or hypothyroidism can be made without problems using any of these methods, with the exception of the FT4-RIA GammaCoat. As expected, patients with euthyroid goiter show, on the average, slightly lower parameters for FT4. In pregnancy all direct and indirect parameters for FT4 have a tendency to lower values after the first trimester. This trend is most distinct for the T4/TBG ratio. A weak negative correlation of FT4 parameters with basal TSH, which does not exceed the upper normal range, however, can be interpreted in the sense of a relative hypothyroxinemia. Under contraceptive estrogen medication FT4 parameters do not fall outside the normal range, with the exception of the FT4-RIA ImmoPhase assay which yields a significantly increased frequency of high FT4 levels. On therapy with phenytoin FT4 values are generally lower than in controls. FT4 parameters in patients with renal protein loss of more than 2 g daily do not behave uniformly. While three of the FT4-RIAs tested (ImmoPhase, GammaCoat, Amerlex) show a tendency to lower values, the results of the remaining FT4 parameters do not differ significantly from the distribution of normals. The study leads to the conclusion that indirect FT4 parameters are still useful in the diagnosis of thyroid function; currently available FT4 radioimmunoassays may yield comparable results. With regard to the varying quality of the various commercial test kits, the choice between FT4-RIAs and indirect FT4 parameters does not depend primarily on clinical but on technical viewpoints.

[Differential diagnosis of thyroid nodules. Sonography as a complement to scintigraphy and puncture cytology]

The place of ultrasound in the diagnosis of thyroid nodules was assessed in 384 patients by comparing its findings with those obtained on palpation, scintigraphy, fine-needle cytology and (in 45 cases) histology. Further diagnosis of scintigraphically "cold" nodules is the main indication for ultrasound examination in goitre-endemic areas. In 13 of 69 cases of a cold nodule with complex or echo-poor echo image proved it to be malignant, while in 74 with cold nodules but with a normal or increased echo pattern there was no malignant tumour. Thus, if the echo pattern is "complex" or "echo-poor" urgency of surgical intervention is strengthened, while with echo-normal or echo-rich nodules or cysts indications for operation are relative. In future, a combination of scintigraphy, ultrasound and cytology (ultrasound-guided small-needle biopsy) will give the highest rate of diagnostic accuracy in the differentiation of malignant from benign thyroid lesions.

[Combined disease picture of an autonomous thyroid adenoma with acute and chronic thyroiditis]

This is a case report of a 20 year old woman suffering from a single toxic hot nodule of the thyroid gland. Following inflammation of the neck a cystic nodule with a thick fibrotic capsule was resected. Histology revealed a follicular adenoma with central necrosis surrounded by chronic fibrosing thyroiditis with intima proliferation of the blood vessels similar to Riedels thyroiditis.

Direkte und indirekte Parameter für das freie Thyroxin

Teil II der Studie zur klinischen Wertigkeit von direkten und indirekten Parametern für das freie Thyroxin untersucht die diagnostische Treffsicherheit der FT4-RIAs ImmoPhase, GammCoat, Liquisol, Amerlex und LisoPhase im Vergleich zum FT4-Index und zum T4/TBG-Quotienten. Der Simultanvergleich der Methoden erfolgt an einem sorgfältig klassifizierten Kollektiv (n = 640) von Patienten mit normaler und gestörter Schilddrüsenfunktion unter Einbeziehung von Transportprotein-Anomalien (Gravidität, Östrogen-Medikation, Hydantoin-Therapie, renaler Eiweiß-Verlust). Die im endemischen Jodmangelgebiet ermittelten Normbereiche für das FT4 stimmen gut mit den Herstellerangaben und den Ergebnissen anderer Arbeitsgruppen überein. Die Normbereiche der einzelnen Kits sind untereinander allerdings kaum vergleichbar. Die Abgrenzung der Euthyreose von der Hyper-und Hypothyreose erfolgt bis auf den FT4-RIA GammaCoat bei allen geprüften Testverfahren problemlos. Euthyreote Patienten mit blander Struma weisen erwartungsgemäß im Mittel leicht niedrigere Parameter für das FT4 auf. In der Gravidität zeigen sämtliche direkten und indirekten Parameter für das FT4 eine Tendenz zu erniedrigten Werten ab dem 2. Trimenon. Dieser allerdings unterschiedlich stark ausgeprägte Trend ist am deutlichsten beim T4/TBG-Quotienten. Die angedeutete negative Korrelation der FT4-Parameter mit dem basalen TSH, das allerdings nicht die obere Normgrenze überschreitet, kann im Sinne einer relativen Hypothyroxinämie interpretiert werden. Unter antikonzeptioneller Östrogen-Medikation finden sich, mit Ausnahme eines FT4-RIA, keine vom Normbereich abweichenden Ergebnisse der verschiedenen FT4-Parameter. Der FT4-RIA ImmoPhase zeigt hier signifikant gehäuft erhöhte FT4-Werte. Die Therapie mit Diphenylhydantoin führt im Vergleich zum Normalkollektiv generell zu durchschnittlich etwas niedrigeren FT4-Werten. Das Verhalten der FT4-Parameter bei Patienten mit renalem Eiweißverlust von mehr als 2 g/d ist uneinheitlich: Während drei der geprüften FT4-RIAs (ImmoPhase, GammaCoat, Amerlex) eine Tendenz zu niedrigeren Werten aufweisen, weichen die Ergebnisse der übrigen FT4-Parameter nicht sicher vom Normbereich ab. Die Studie führt zu den Schlußfolgerungen, daß indirekte Parameter für das FT4 für die Basisdiagnostik der Schilddrüsenfunktion weiterhin brauchbar sind; heute verfügbare FT4-RIAs können vergleichbare Aussagen bieten. Bei unterschiedlicher Qualität der verschiedenen kommerziellen Test-Kits ist die Auswahl zwischen FT4-RIAs und indirekten FT4-Parametern nicht primär von klinischen, sondern von methodisch-technischen Gesichtspunkten bestimmt.

[Possibilities and limits of thyroid sonography in the diagnosis of thyroid cancer]

The echographic appearance of 19 histologically confirmed malignant thyroid tumours has been analyzed. The value of information by ultrasonography is compared to scintigraphy and fine-needle aspiration biopsy. All patients demonstrated a sonographic pattern of relatively low amplitude, sparse and disordered echoes. Extended thyroid tumours (T2-3) exhibited a serrated marginal border as a sign of the infiltration to the surrounding thyroid tissue. The clinically important separation of solid and cystic nodules can always be made with certainty. Provided that a subtile examination technique is used, ultrasonography can be of great value in choosing the adequate therapy in scintigraphic cold nodules. Diagnostic ultrasound also yields information concerning the reliable and reproducible classification and accurate location of circumscribed thyroid lesions. In all cases, however, the ultrasound pattern did not provide reliable clues as to their histology. A successful differentiation between benign and malignant solid nodules can be obtained only by cytology and histology. Ultrasonography, scintigraphy and aspiration biopsy, therefore, are complementary methods.

[Mechanical properties and acid solubility of the dental surface. I. Microhardness]

The present paper deals with the relationship between microhardness, and the circumferential as well as radial location of the test points on the tooth surface. The measurements did not indicate a significant correlation between the average hardness of the tooth sections, and their location on the circumference. The average hardness of the sections on one probe, however, showed a large variation. Hardness was also correlated with the distance from the enamel surface. There was a steep hardness gradient in the outermost 50 micrometer thick enamel layer: hardness increased in the direction to the dentino-enamel junction. The investigated enamel layer seems to be layer of less mineralized enamel which might have its origin in de-, and remineralization processes on the enamel surfaces.

[Dental studies on the protective effect of breast feeding]

The frequency of disease for children who were breast fed as babies is lower than that for children who were bottle fed. Breast milk contains specific and nonspecific proteins which act against pathogens. The influence of breast milk on the development of juvenile periodontitis was examined. It was shown that, out of 55 children raised on bottle milk, 9 children up to 14 years of age showed inflammatory changes in the gingiva while only 1 child out of the 17 fed with breast milk during the first few months of life had gingivitis. The lower frequency of gingivitis can probably be explained by the immunopathology of periodontitis.

[Comparative studies of the hardness of dental calculus after the use of 2 dentifrices]

A method was described for recording the mechanical characteristics of tartar using objectively comparable test data. This method was used to study tartar which had formed when different tooth pastes were used. The results of this study indicate that 1. Tartar formed when different tooth pastes are used may exhibit different characteristics; 2. The dynamic measurement of indentation is suitable for quantitative determination of the mechanical characteristics of tartar. These mechanical characteristics have not been ascertainable until now.

[Comparative clinical and photogrammetric studies on the marginal periodontium after the use of dentifrices]

A suggestion was made for testing the therapeutic effect of certain substances on gingival inflammation. Gingivitis was induced in 60 subjects by discontinuing of all forms of oral hygiene. Three tooth pastes, one of which was a placebo, were used for the study. Regression of the inflammation was determined with the periodontal indexes and photogrammetry. Photogrammetry appears to be well suited for objective evaluation of the therapeutic value of certain substances.

[The effect of periodontal resistance on experimental gingivitis]

The distribution and degree of severity of periodontal diseases depends on many different factors. One of the factors, periodontal resistance, was studied in 62 subjects. The test with experimental gingivitis showed that the dividing the subjects into periodontal-resistant and periodontal-insufficient groups led to more differentiated results.

[Comparative phorogrammetric studies on a periodontal index]

Reproducibile results are difficult to obtain with subjectively recorded periodontal indexes. The information acquired via such indexes therefore may be called into question. Inflammation of the gingiva was induced in 15 subjects. The degree of gingival swelling was determined via monophotogrammetry; the degree of inflammation, with the PMA index which emphasizes the symptom "swelling". The results were compared and discussed. It is highly probable that the PMA index is subjectively overrated.

[Experimental gingivitis--a photogrammetric comparative study]

Inflammation of the gingiva was induced in 29 subjects ranging in age from 20 to 29 by discontinuing all forms of oral hygiene for three weeks. The course of the inflammation was followed during the developmental period and the following therapy phase with the PMA index, the plaque index, and monophotogrammetry. The results tend to indicate that gingival swelling develops more gradually and recedes more rapidly after treatment has been instituted than could be assumed from the current standard periodontal indexes.

[Photogrammetric studies on the degree of swelling in the inflamed gingiva]

A photographic method was described with which changes in the swelling of the gingiva can be objectively determined. During exposure of the film, the flash device projects vertical lines on the teeth and gingiva. These lines are photographed with a compact camera which the subject holds with his teeth over a separate occlusion template. Increased swelling of the gingiva was demonstrated in eight subjects during an observation period of 21 days in which no oral hygiene was carried out.