[Differential diagnosis of cystic and cystic-like lesions of the jaw]

The difficulties in the differential diagnosis of jaw cysts are demonstrated by 10 selected case studies. Panorama radiographies are basic for radiodiagnosis. Supplementary radiographs, including CT, are often necessary. In general, the final diagnosis can be given after synopsis of clinical, radiographic and patho-histological findings.

Molecular organization of dinoflagellate ribosomal DNA: evolutionary implications of the deduced 5.8 S rRNA secondary structure

The 5.8 S rRNA gene of Prorocentrum micans, a primitive dinoflagellate, has been cloned and its 159 base pairs (bp) have been sequenced along with the two flanking internal transcribed spacers (ITS 1 and 2), respectively, 212 and 195 bp long. Nucleotide sequence homologies between several previously published 5.8 S rRNA gene sequences including those from another dinoflagellate, an ascomycetous yeast, protozoans, a higher plant and a mammal have been determined by sequence alignment. Two prokaryotic 5'-ends of the 23 S rRNA gene have been compared owing to their probable common origin with eucaryotic 5.8 S rRNA genes. Several nucleotides are distinctive for dinoflagellates when compared with either typical eucaryotes or procaryotes. This is consistent with an early divergence of the dinoflagellate lineage from the typical eucaryotes. The secondary structure of dinoflagellate 5.8 S rRNA molecules fits the model of Walker et al. (1983). Conserved nucleotides which distinguish dinoflagellate 5.8 S rRNA from that of other eucaryotes are located in specific loops which are assumed to play a structural role in the ribosome. A 5.8 S rRNA phylogenetic tree which is proposed, based on sequence data, supports our initial assumption of the dinoflagellates.

The native structure of dinoflagellate chromosomes and their stabilization by Ca2+ and Mg2+ cations

Native chromosomes from the primitive dinoflagellate Prorocentrum micans were isolated without recourse to chemicals from purified nuclei frozen in liquid nitrogen. Thawing of the nuclear suspension resulted in the disruption of nuclear membrane, and the released chromosomes were incubated in various conditions or directly observed by electron microscopy after spreading. (1) Observations of whole mounted chromosomes confirmed that they were organized in a double-helical bundle of chromosomal fibers. (2) Investigations of these high-ordered chromosomal fibers at high magnification revealed helical compaction of nucleofilaments in a hierarchy of six organization levels (from the DNA to the double helical bundle forming the chromosome). (3) This peculiar architecture was shown to be stabilized mainly by divalent cations; the behavior of native chromosomes incubated in a low concentration of either EDTA or EGTA strongly suggested that the chromosome has two different cation sites, one for Ca2+ and the other for Mg2+.

A high level of thymine replacement by 5-hydroxymethyluracil in nuclear DNA of the primitive dinoflagellate Prorocentrum micans E

The nuclei of dinoflagellate protists display several distinctive features which make it difficult to assign these organisms as either eukaryotes or prokaryotes. We investigated some physical properties of purified nuclear DNA from the primitive species Prorocentrum micans. Nuclear DNA was separated on a CsCl gradient, into two components, which banded with relative densities of 1.7240 g/cm3 for the main peak and 1.7301 g/cm3 for the heavy shoulder. Thermal denaturation of nuclear DNA displayed a broad profile with a Tm of 71 degrees C. A large discrepancy was thus revealed between the apparent (G + C) content as determined from density (65.4%) and that from Tm (41.7%) while the actual (G + C) content determined by 32P nucleotide chromatography was shown to be 57.1%. The abnormal behaviour of this DNA was due to the presence of an unusual nucleotide which was identified as 5-hydroxymethyluridylate (HOMedUMP) from its chromatographic and U.V. spectral characteristics. It amounted to 13.4% of the total nucleotides and replaced an average of 62.8% of the expected thymidylate (dTMP). Composition analysis of different fractions of the CsCl gradient revealed that the unusual pyrimidine, 5-hydroxymethyluracil, was not uniformly interspersed with thymine in the DNA; the substitution rate increased with the relative density of the DNA. A minor component was also found, tentatively identified as 5-methylcytidylate (MedCMP) from its chromatographic properties, which amounted to less than 0.5 mol percent.

[Health education and group work during in-patient rehabilitation following myocardial infarction (author's transl)]

Starting from the usual in-patient rehabilitation measures for myocardial infarction patients and based on the authors' clinical experiences, a working model is presented concerning the health educational care of patients undergoing rehabilitation procedures immediately following infarction or bypass operation. The new concept is based on a psychosomatic view of the cardiovascular diseases, and uses group-dynamic elements in its methodological approach. The rehabilitational tasks of health education are understood as therapeutic strategies and are aimed at achieving changes on the attitudinal and behavioural level.

Distinctive features of dinoflagellate chromatin. Absence of nucleosomes in a primitive species Prorocentrum micans E

The absence of nucleosome-like structures from purified nuclei of the primitive dinoflagellate Prorocentrum micans was demonstrated by three means. i) Electron microscopy revealed mostly thin, smooth 6-nm nucleofilaments in chromatin incubated at various ionic strengths and either fixed in 0.1% glutaraldehyde or unfixed. No "beads-on-a-string" structure was found. ii) Analysis of nuclear proteins showed that low amounts of basic proteins were present (basis proteins: DNA less than 0.1), the two major one with molecular weights 12 000 and 13 000 and that histones characteristic of eucaryotes were absent. iii) Digestion of the nuclei with micrococcal endonuclease of DNase I did not result in partially digested DNA fragment repeats. Only about 10% of the bulk of the nuclear DNA was digested by micrococcal endonuclease. The high molecular weight of the remainder suggests particular protection against this type of nuclease. In the light of these distinctive nuclear features, we discuss the evolutionary position of the dinoflagellate protists with respect to the procaryotes and eucaryotes.

Natural fluorescence properties of brome mosaic virus protein

Some of the fluorescence properties of brome mosaic virus protein in different states of aggregation (dimer, capsid) have been studied, in particular the emission spectra, fluorescence quantum yields and lifetimes, as well as the effect of external quenchers and of temperature on the fluorescence. Brome mosaic virus protein, which contains two tryptophan and five tyrosine residues per monomer, displayed an unusual fluorescence spectrum maximum of 308 nm at pH 7.4 when excited at 280 nm. The emission maximum was shifted to 327 nm when excited at 295 nm. Analysis of the results showed that the tyrosine emission is characterized by a high value for the quantum yield (phi = 0.07), which is consistent with a location of most of these residues in helical regions of the protein, while the tryptophan emission is strongly quenched (phi=0.035). The effects of external quenchers suggested that two kinds of tryptophan residues might exist, one buried (phi=0.056) and one exposed, the quantum yield of the latter being particularly low (phi=0.014). The tryptophan fluorescence quenching is partially removed at pH 8.4 and totally eliminated after chemical (guanidinium chloride) or thermal denaturation of the protein. Formation of capsid induced an additional quenching of the exposed tryptophan residue while interaction with the RNA in the virus did not modify the emission parameters of the protein.

RNA viruses: stabilization of brome mosaic virus

The relative importances of protein-protein and RNA-protein interactions in stabilizing the architecture of brome mosaic virus particles are discussed in the light of the following experimental evidence: (a) disassembly pathways of the virus particles, (b) reassembly of the virus and self-association capacity of the protein moiety, and (c) the role of divalent cations in virus stabilization, and their relevance to localization of the RNA in the virus particles. Evidence is given that the capsid of BMV is primarily stabilized by hydrophobic bonds at low pH, but not around and above neutrality where RNA-protein electrostatic interactions are essential to the integrity of the virus particles. A model is proposed for the structure of BMV in the different configurational states.

Ergebnisvergleich der 99mTc-Polyphosphat-Kamera-(Sequenz, Funktionsszintigraphie, der 85Sr-, 87mSr-Scanner-Szintigraphie und radiologischer Methoden in der Orthopädie

Vergleichende Studien zwischen Radiologie (= R; Röntgen, Thermographie, Angiographie) und Nuklearmedizin (= NM; Scanner-, Szintillationskamera - Sequenzszintigraphie) anhand von 339 Patienten mit Knochenerkrankungen erbrachten folgende Ergebnisse:

Die Thermographie erwies sich zur Aufdeckung von Knochenerkrankungen weniger geeignet als der Scan.

Die Angiographie wurde vorzugsweise zur Diagnose maligner Tumoren verwendet.

Die Sequenzszintigraphie mittels Anger-HP-Szintillations-Kamera und Intertechnique-Cine-System erlaubt die Feststellung des kinetischen Verhaltens des Tumors: Früh gesteigerte TcPoP-Akkumulation wurde bei Tumoren mit hoher Perfusion festgestellt (Sarkom), späte Akkumulation in jenen mit niedriger Perfusion (Osteom).