Dental care approach in patients with osteopetrosis.

AIM: To describe dental and dentofacial characteristics observed in patients diagnosed with osteopetrosis and to advise a dental care approach in these patients. METHODS: Four patients were clinically diagnosed with osteopetrosis, characterised by increased bone density, bone marrow failure, blindness and deafness due to compression of cranial nerves. All patients were dentally screened at different ages (2.5-31 years) and three of them were treated with a haematopoietic stem cell transplantation (HSCT) at the age of 6 months, 1 and 3.1 years. RESULTS: All patients showed similar dental characteristics but varying severity and extent. Dental pits, abnormalities in form, agenesis and enamel deformations are seen. The eruption of the permanent dentition occurs at a slow rate, primary teeth can persist, have no successor, and aberrant form of the primary/permanent teeth can delay eruption. Uneven surfaces and atypical dental crowns combined with visual impairment make brushing of the teeth and plaque removal more difficult to manage. CONCLUSION: Dental problems such as delay in tooth eruption, crown anomalies and agenesis are seen in the patients diagnosed with osteopetrosis, although the severity and extensiveness of the symptoms differ and possibly depend on the age of the patient at HSCT. Treatment management: Frequent dental follow-up examinations are necessary for guiding the eruption and professional dental cleanings. Aid in the eruption can be helpful. In the case of surgical interventions, an antibiotic prophylaxis is advised. A fluoride treatment can be added to prevent caries. The role of HSCT in dental findings needs further research.

Fermentation and recovery of the EcoRI restriction enzyme with a genetically modified Escherichia coli strain.

The fermentation and recovery of the EcoRl restriction endonuclease with a genetically modified Escherichia coli strain is investigated. Vast amounts of product could be obtained after cultivation in a 20-L computer-coupled pilot fermentor and purification of the recovered wet cells. It was found that in the end the product is at least inhibitory and probably lethal to the cells (the lethality has been proven with genetic experiments) so that optimum yield requires an optimized choice for the time instant of induction. Growth after induction and product formation require substantial amounts of oxygen, which must be supplied if a high population level is to be achieved. pH control may alleviate the burden of high oxygen supply. Quantitative assessment after the different purification stages indicate that approximately 15% active enzyme can be obtained from the total amount produced.