The balanced and the unbalanced chromosome aberrations of acute myeloid leukemia may develop in different ways and may contribute differently to malignant transformation

Two general types of clonal chromosome abnormality are observed in de novo acute myeloid leukemia (AML): the unbalanced aberrations with visible gain or loss of chromosome material and the balanced aberrations without such visible gain or loss. AML can be induced by therapy with cytostatic drugs and radiation. The alkylating agents reacting directly with DNA induce AML which often presents as myelodysplasia with unbalanced aberrations, primarily loss of chromosome material. Cytostatic agents targeting DNA-topoisomerase II, frequently administered together with alkylating agents or cisplatin, induce the same type of leukemia. In addition, they often induce another type with a more rapid onset and with specific balanced chromosome aberrations rarely observed after therapy with alkylating agents alone. All of the most important chromosome aberrations found in de novo AML are now also found in therapy-related AML (t-AML); thus, t- AML may serve as a model in the search for mechanisms leading to the development of AML in general. Unbalanced chromosome aberrations with partial deletions or with loss of whole chromosomes may develop as a result of alkylation of DNA or other cellular targets. Balanced chromosome aberrations, on the other hand, may develop as illegitimate recombinations related to the activity of DNA-topoisomerase II. The balanced translocations contribute to malignant transformation by the formation of abnormal chimeric genes, whereas deletions may contribute by the loss of putative tumor suppressor genes. In either situation, the chromosome changes provide the altered cells with a proliferative advantage compared with normal cells.     

Sacroiliac joint pain due to bacterial infection: a report of two cases

Isolated infection of the sacroiliac joint is a rare cause of low back pain. Delayed diagnosis can result in significant morbidity. The diagnosis may be missed initially if physicians do not consider the possibility of infection. The clinical index of suspicion should increase in the presence of certain historical and examination findings. These include intravenous drug use, immunosuppression, recent infection elsewhere, fever and warmth or swelling over the sacroiliac joint. Two cases of sacroiliac joint pain due to Staphylococcus aureus infection are presented, with an overview of the etiology, diagnosis and management of the disorder.     

Staphylococcus aureus in patients with cystic fibrosis: An epidemiological analysis using a combination of traditional and molecular methods

Summary An epidemiological analysis ofStaphylococcus aureus was conducted in a study group of 157 cystic fibrosis patients cultured over a 30-month period. The resultingS. aureus isolates were categorized by bacteriophage type, plasmid profile, and (in some instances) chromosomal restriction fragment pattern of the culture-positive patients withS. aureus (34 of 157) 44% only were sporadically infected while 68% shared identical strains with one or more other patients. Six patients exhibited persistent infection (for up to ten months) which, in three individuals, occurred as cycles of carriage and reappearance. By contributing toward our understanding of the persistence and spread ofS. aureus in cystic fibrosis patients these data should aid in clarifying the role this organism may play in the course of the disease.

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Epidemiologische Analyse des Auftretens von Staphylococcus aureus bei Mukoviszidosepatienten mit Hilfe konventioneller und molekularer Methoden

Zusammenfassung Das Auftreten vonStaphylococcus aureus wurde bei 157 Mukoviszidosepatienten über 30 Monate hin analysiert. Dazu wurden dieS. aureus-Isolate nach Lysotyp, Plasmidmuster sowie in einigen Fällen dem Restriktionsmuster ihrer chromosomalen DNS klassifiziert. Danach konnte in 44% aller Patienten, in deren SputaS. aureus nachweisbar war, bei aufeinanderfolgenden Episoden ein Wechsel desS. aureus-Typs beobachtet werden. IdentischeS. aureus-Typen wurden bei 68% der Patienten gefunden, wobei derselbe Typ in bis zu fünf verschiedenen Patienten auftrat. Bei sechs Patienten persistierte derselbeS. aureus-Stamm (bis zu zehn Monate), bei drei unter ihnen war er zwischendurch nicht mehr nachweisbar. Die Ergebnisse weisen auf die Möglichkeit der Ausbreitung vonS. aureus-Stämmen unter Mukoviszidosepatienten hin.