Purification and biochemical characterization of the G4 resolvase and DNA helicase FANCJ

G-quadruplex (G4) DNA or RNA poses a unique nucleic acid structure in genomic transactions. Because of the unique topology presented by G4, cells have exquisite mechanisms and pathways to metabolize G4 that arise in guanine-rich regions of the genome such as telomeres, promoter regions, ribosomal DNA, and other chromosomal elements. G4 resolvases are often represented by a class of molecular motors known as helicases that disrupt the Hoogsteen hydrogen bonds in G4 by harnessing the chemical energy of nucleoside triphosphate hydrolysis. Of special interest to researchers in the field, including us, is the human FANCJ DNA helicase that efficiently resolves G4 DNA structures. Notably, FANCJ mutations are linked to Fanconi Anemia and are prominent in breast and ovarian cancer. Since our discovery that FANCJ efficiently resolves G4 DNA structures 15 years ago, we and other labs have characterized mechanistic aspects of FANCJ-catalyzed G4 resolution and its biological importance in genomic integrity and cellular DNA replication. In addition to its G4 resolvase function, FANCJ is also a classic DNA helicase that acts on conventional duplex DNA structures, which are relevant to the enzyme's role in interstrand cross link repair, double-strand break repair via homologous recombination, and response to replication stress. Here, we describe detailed procedures for the purification of recombinant FANCJ protein and characterization of its G4 resolvase and duplex DNA helicase activity.

Generalisiertes Schmerzsyndrom, Fieber und Somnolenz bei einem 81-j�hrigen Patienten

We present a case of an 81-year-old diabetic man with anaerobic sepsis due to acalculous cholecystitis. The patient was admitted to our hospital with a seven-day history of severe abdominal pain accompanied with fever and somnolence. Blood cultures taken during the initial procedure developed Clostridium perfringens. The patient was immediately treated with parenteral penicillin. The ultrasonography pointed out the case: the gall bladder was found to be distended and slightly thickened. This result was interpreted as an acute non-emphysematous cholecystitis. The material obtained by needle aspiration and therapeutical emptying of the gall bladder revealed large gram positive rods, that also proved to be Clostridium perfringens. The patients course afterwards was uneventful. Antibiotics were continued and he was discharged after 13 days in a stable condition.

[Value of sonography in assessing nodular changes of the thyroid in an endemic goiter area]

In an area of endemic goiter 304 patients with an increased thyroid gland were examined by palpation, sonographically and partly scintigraphically. The average age was 37 (12-78) years, the average age of the patients with nodular changes of the thyroid gland 38-44 years. Patients with a diffuse struma were significantly younger with an average age of 33 years. A false-positive enlargement of the thyroid gland established by palpation occurred in 16.1% (n = 49/304). In the sonographic examination 148 out of 304 patients revealed a diffuse enlargement of the thyroid gland without provable nodular change. However, in about one third already more or less clearly characterized regressive changes could be observed. In 156 of the 304 patients 109 times solitary nodes and 47 times multinodular changes were established sonographically. In more than one third of all nodular goiters or one fifth of all patients examined a cyst was demonstrated sonographically. Two thirds of the sonographically established nodular changes were, however, solid. In 53 of all 304 examined patients could sonographically be established additional, unexpected nodes which had escaped the palpation and partly also the scintigraphic investigation. In 14% the node suspected by palpation could not be ascertained sonographically. According to the echo structure echo-poor and echo-equal solid nodes dominated. The frequency of carcinomata of the solid nodes was 6.7%. Apart from 4 echo-poorly and 2 complexly structured nodes a carcinoma of the thyroid gland demonstrated itself sonographically to the same echo. Finally conclusions are drawn for the diagnostics of the thyroid gland in the endemic area of goiter.

[Value of sonographic representation of the portal artery in clinical practice]

While in chronic liver diseases we up to now above all depended on laparoscopic indices of the hypertension of the portal vein, also the non-invasive sonography is able to prove an adequate morphological substrate in form of the dilated splenic vein and the portal vein. A comparative study of 50 patients with liver cirrhosis who underwent laparoscopy shows significantly higher values in patients with clear portal hypertension. Provided a correct valuation of the findings by the clinical and a subtle examination technique, the non-invasive sonographic estimation of the portal vein represents a prognostically important diagnostic contribution in patients with chronic liver diseases.