[Contribution of computer tomography to the evaluation of space-occupying processes and abnormalities of the skeletal system]

The contribution made by computed tomography to the diagnostics of the skeletal system was studied in the basis of 53 examinations in patients with space-occupying growths and malformations. With reference to clinical final diagnoses the CT findings were graded into I. Correct diagnosis or diagnosis by exclusion, II. Contribution to determining the growth of the process, III. No additional information obtained via CT. The distribution of these grades was as follows: Grade I = 34%, II = 49%, III = 17%. Indications for CT of the skeletal system were based on the following problems: primary malignant bone tumours; bone metastases in the region on the vertebral column; benign and potentially malignant bone tumours and abscesses in the region of the skeleton itself and of the skull; suspected diastematomyelia; assessment of the vertebral canal in case of suspected inflammatory or tumorous changes of the adjacent areas as well as exclusion of osseous changes in the region of the vertebral canal with peripheral neurological symptoms. CT serves to determine the exact dimension of the growth; to prove infiltration of organs and structures; for the planning of operations; for controlling the course; and for diagnosing relapses.

Long-term suppression of central serotonergic activity by corticosteroids: a possible model of steroid-responsive myoclonic disorders

Chronic administration of cortisol succinate (12.5 mg per kilogram per day) to guinea pigs suppressed jumping behavior induced by 1-5 hydroxytryptophan and abolished diurnal threshold variations of this behavior. Chronic corticosteroid administration did not alter threshold or diurnal variations of apomorphine-induced stereotypy. These observations suggest that the efficacy of corticosteroids in some human myoclonic movement disorders may be related to central serotonergic inhibition.

A family with whistling-face-syndrome

A family with 7 persons affected with whistling-face-syndrome in 3 successive generations is described. The clinical variability of the syndrome within one family is demonstrated by means of examining particular characteristics of four daughters in the family. Six affected persons are female; the only male carrier died in early infancy because of the severity of symptoms. The known autosomal dominant inheritance combined with clinical variability and bias towards female manifestation is present in this family.

Effect of transient lambda prophage induction on ultraviolet light resistance and recombination in Escherichia coli

Transient induction of lambda prophage increases the ultraviolet light resistance of most exponentially growing Escherichia coli lysogens. Resistance is increased in wild-type, recB, recB recC, recB recC recF, and recB recC recL hosts. No enhancement in recA lysogens was found, nor was there enhancement in stationary cultures. Enhancement was dependent upon the lambdared recombination system. Transient induction also increases the genetic recombination rate in recB lysogens as measured in Hfr X F- matings.

Hyphal walls of isolated lichen fungi: autoradiographic localization of precursor incorporation and binding of fluorescein-conjugated lectins

The hyphal walls of three mycobionts, isolated from the lichens Xanthoria parietina, Tornabenia intricata and Sarcogyne sp. were investigated by two techniques: microautoradiography of fungal colonies exposed to radioactive carbohydrate precursors: and binding, in vivo, of fluorescein conjugated lectins to hyphal walls of such colonies. N-[3H] acetylglucosamine was readily incorporated into tips, young hyphal walls and septa of the three mycobionts and the free-living fungus Trichoderma viride, but not into Phytophthora citrophthora, indicating that chitin is a major component of the mycobionts' hyphal walls. All three mycobionts, but neither of the free-living fungi, incorporated [3H] mannose and [3H] mannitol into their hyphal walls. Fluorescein-conjugated wheat germ agglutinin was bound to the hyphal walls of the three mycobionts and T. viride, but not to the walls of P. citrophthora; the binding pattern was similar to the grain pattern obtained in autoradiographs after short N-[3H]acetylglucosamine labelling. As wheat germ agglutinin binds specifically to chitin oligomers, the lectin binding tests further confirmed that chitin is a mycobiont hyphal wall component. Binding characteristics of several fluorescein-conjugated lectins to the three mycobionts indicated that this technique can yield useful information concerning the chemical composition of hyphal wall surfaces.

Modification of the regulatory properties of pyruvate kinase of Neurospora by growth at elevated temperatures

Pyruvate kinase (EC 2.7.1.40) was isolated from Neurospora crassa mycelium grown at 28 degrees C (PK-28) and at 42 degrees C (PK-42). The regulatory properties, particularly the response towards the allosteric effector fructose 1,6-diphosphate (FDP), was different in the two enzymes. PK-28 showed an activation by FDP but PK-42, under comparable conditions, appeared to be activated by low concentrations of FDP and inhibited by higher ones. For PK-28, complex formation with FDP results in a lowering of the isoelectric point from 6.40 to 5.50, representing the pI of the unliganded enzyme and that of the complex, respectively. In contrast to this, PK-42 exhibits a weak binding to FDP as suggested by a lack of decrease in the isoelectric point on treatment with comparable concentrations of FDP. Studies with quenching of aromatic residue fluorescence of PK-28 and PK-42, following binding of FDP, indicate that although this ligand binds to both types of enzymes the affinity for the two is vastly different. Dissociation constants of 9.3 muM and 0.1 mM were calculated for the binding of FDP to PK-28 and PK-42, respectively. It is concluded that growth at elevated temperatures induced a conformational change in the pyruvate kinase leading to partial desensitization of the allosteric site. The nature of the factor(s) responsible for this change is not understood at present.

The Escherichia coli UV endonuclease (correndonuclease II)

An endonuclease from Escherichia coli which acts specificially upon UV-irradiated DNA (correndonuclease II) and is absent from the uvrA and uvrB mutants has been isolated and partially chacterized. The enzyme is present in normal amounts in the urvC mutant. It elutes from phosphocellulose at about 0.25 M potassium phosphate (pH 7.5) and passes through dialysis tubing. The enzyme binds tightly to UV-irradiated DNA but does not bind to unirradiated DNA. The enzyme incises irradiated DNA to the 5' side of a pyrimidine dimer and leaves a 5'-phosphoryl terminus which can be resealed with polynucleotide ligase. The Km of the enzyme is about 1.5 X 10(-8) M dimers. Endonucleolytic activity of the enzyme is inhibited by caffeine with a KI of about 10mM.

An endonuclease from Escherichia coli that acts preferentially on UV-irradiated DNA and is absent from the uvrA and uvrB mutants

At least two endonucleolytic activities that preferentially incise ultraviolet (UV)-irradiated DNA exist in extracts of E. coli. These two activities can be separated by phosphocellulose chromatographic fractionation. The subject of this paper is one of these activities, which elutes from phosphocellulose with 0.25 M potassium phosphate, pH 7.5. This endonucleolytic activity specific for UV-irradiated DNA is absent from partially purified extracts of uvrA and uvrB mutants, which are defective in excision of pyrimidine dimers, but is present in normal amounts in the uvrC excision-defective mutant. The enzyme binds very tightly and specifically to UV-irradiated DNA. Binding can be prevented by prior treatment of the irradiated DNA with photoreactivating enzyme. This binding activity is absent in uvrA and uvrB mutants, but present in uvrC and uvrD mutants.

Oxygen effect in gamma-irradiated DNA

Purified, dry DNA and dry nucleoprotein were irradiated with 60Co-γ-rays under a nitrogen or oxygen atmosphere. The DNA was isolated from the irradiated nucleoprotein. In the DNA the following radiation induced changes were investigated: Double strand breaks, single strand breaks and crosslinks between the DNA molecules. An oxygen effect (OER > 1) was found for all of these events except for crosslinks in irradiated DNA. In the nucleoprotein, the oxygen effect is more marked than in pure DNA.