Homozygosity mapping of achromatopsia to chromosome 2 using DNA pooling

Achromatopsia is an autosomal recessive disease of the retina, characterized clinically by an inability to distinguish colors, impaired visual acuity, nystagmus and photophobia. A genome-wide search for linkage was performed using an inbred Jewish kindred from Iran. To facilitate the genome-wide search, we utilized a DNA pooling strategy which takes advantage of the likelihood that the disease in this inbred kindred is inherited by all affected individuals from a common founder. Equal molar amounts of DNA from all affected individuals were pooled and used as the PCR template for short tandem repeat polymorphic markers (STRPs). Pooled DNA from unaffected members of the kindred was used as a control. A reduction in the number of alleles in the affected versus control pool was observed at several loci. Upon genotyping of individual family members, significant linkage was established between the disease phenotype and markers localized on chromosome 2. The highest LOD score observed was 5.4 (theta = 0). When four additional small unrelated families were genotyped, the combined peak LOD score was 8.2. Analysis of recombinant chromosomes revealed that the disease gene lies within a 30 cM interval which spans the centromere. Additional fine-mapping studies identified a region of homozygosity in all affected individuals, narrowing the region to 14 cM. A candidate gene for achromatopsia was excluded from this disease interval by radiation hybrid mapping. Linkage of achromatopsia to chromosome 2 is an essential first step in the identification of the disease-causing gene.      

Vergleichende In-vitro-Untersuchungen von selbstbohrenden und selbstschneidenden Schrauben

Self-drilling screws are gaining increasing importance in maxillofacial surgery. This study assesses which screw design, self-drilling or self-tapping, is best suited to various locations of the human skull. With regard to different areas in the human midface, mandible, and cranium, the thickness of cortical bone varies as well as the relative proportion of cortical to cancellous bone. Criteria used to judge the success of screws were minimal insertion torque and minimum temperature, maximum pullout strength, and minimum deformation and destruction of the bone. To mimic the variations in anatomical conditions, 1-mm and 3-mm-thick cortical bone specimens and cancellous bone blocks were prepared. Eight screws of three types (self-tapping, self-drilling/self-tapping, conically shaped self-drilling) were inserted into the different bone specimens. Torque and temperature were measured during the insertion procedure. Subsequently, the screws were carefully removed and the specimens were processed for histological evaluation. The same insertion protocol was used to test the pull-out strength of the screws. The conically shaped screw showed best results in cancellous bone for all parameters. The self-tapping screw with a pilot hole performed best in thick cortical bone and the self-drilling/self-tapping screw performed better than did the others in thin bone. The results suggest the three screw designs to be optimal for different locations of the human skull. This project provides the data for a planned in vivo study that will evaluate the long-term influence of deformation and temperature on stability and osseointegration of the screws.     

In vivo expression of the B7 costimulatory molecule by subsets of antigen-presenting cells and the malignant cells of Hodgkin's disease

The B-lymphocyte/accessory-cell activation antigen B7 (BB1) has been shown in vitro to stimulate T-lymphocyte proliferation and cytokine production via CD28 present on the latter cells. In this study, benign lymphoid tissues, lymphomas, and extralymphoid inflammatory sites were examined immunohistochemically using anti-B7 and other relevant monoclonal antibodies. B7 was expressed by benign transformed germinal center B cells, as it was by B cells of follicular lymphomas. B7 was also expressed by a subpopulation (a mean of 31% to 65%) of macrophages and dendritic cells in a variety of lymphoid tissues. It was present in abundance on all macrophages constituting sarcoid granulomas in lymph nodes. In extralymphoid inflammation, 17% to 35% of macrophages expressed B7 only weakly. Cases of Hodgkin's disease showed expression of B7 by the majority of Reed-Sternberg cells or malignant mononuclear variants, a phenomenon that potentially contributes to the lymphocytic accumulation that is a feature of this condition. CD28+ T cells were seen in all areas where T cells were present. B7+ and CD28+ cells colocalized in, for example, lymphoid follicles, lymph node paracortex, sarcoid granulomas, and Hodgkin's disease tissue, indicating a potential for cellular interaction via these molecules at these sites.     

Elongated coronoid process: CT-based quantitative analysis of the coronoid process and review of literature

Impingement of the enlarged coronoid processes against the medial surfaces of the zygomatic arches and posterior surfaces of the body of the zygomatic bones results in mechanical restriction of the mouth opening. The authors introduce a helpful tool for easy assessment and estimatation of the length of the coronoid process, measured on the CT scans of 40 patients (20 adults, 20 adolescents) and report a case of a 13-year-old boy suffering from restricted mouth opening caused by bilateral hyperplasia of the coronoid process. The CT based analysis resulted in a mean length of the coronoid process of 13.02mm in adults and 12.43mm in adolescents. The 13-year-old boy had a length of nearly 2cm. For comparison, a coronoid/condyle ratio was developed. This ratio showed a value of 0.78 for all patients compared with a value of about 2.0 for the boy. The literature review revealed comparable results to the reported case. Most of the patients were adolescent, male and presented a median history of 2 years until correct diagnosis.     

Bone formation after sinus augmentation with engineered bone

Objectives: The aim of the following investigation was to quantify the resorption rate of tissue-engineered bone grafts in the maxillary sinus using volume measurements. MATERIAL AND METHODS: Sinus floor augmentation using autologous bone grafts from the iliac crest (n=17, group 1) was compared with commercially produced transplants of human cells seeded on polyglycolid-polylactid (PLGA) scaffolds (Oral Bone) (n=14, group 2). RESULTS: The total resorption rate for autologous transplants 3 months post operation was 29%, while the tissue-engineered bone showed a resorption rate of 90%. The autologous bone had a bone density of up to 266-551 Hounsfield units (HU), while sufficient mineralization of tissue-engineered bone was found in only one case (152 HU). CONCLUSION: In this clinical study, the use of autologous cancellous bone grafts in sinus augmentation was more reliable than scaffolds containing cultured osteoblasts. Further tissue-engineered bone transplants should be examined to draw general conclusions about the use of tissue-engineered grafts compared with autologous bone grafts for maxillary sinus augmentation.