Chromogenic identification of genetic regulatory signals in Bacillus subtilis based on expression of a cloned Pseudomonas gene.

A method to isolate fragments of DNA that promote gene expression in Bacillus subtilis is described. The system is based on production of catechol 2,3-dioxygenase [CatO2ase; catechol:oxygen 2,3-oxidoreductase (decyclizing), EC 1.13.11.2] encoded by the Pseudomonas putida TOL plasmid gene xylE. The gene was transferred to aB. subtilis/Escherichia coli plasmid vector to construct pTG402. Although xylE is functionally expressed in E. coli, CatO2ase is not detected in B. subtilis unless a fragment of DNA capable of promoting gene expression is ligated into a cleavage site on pTG402 upstream from xylE. Fragments of chromosomal DNA from B. subtilis, Bacillus licheniformis, Bacillus pumilus, and E. coli are shown to promote xylE gene expression in B. subtilis. The special feature of the system is the method of detection: colonies of cells that express xylE become yellow within seconds after selection plates are sprayed with catechol, a colorless substrate that is converted by CatO2ase to the yellow product, 2-hydroxymuconic semialdehyde. The complete nucleotide sequence of xylE is presented. Strong complementarity between the ribosome binding site and 16S rRNA suggests that xylE mRNA translation in B. subtilis may commence at the same site as that recognized by P. putida. Identity of CatO2ase produced in B. subtilis, E. coli, and P. putida support the hypothesis. Our sensitive color assay offers an approach to develop plasmid gene expression vectors for a wide variety of host organisms.     

Ultrasound assessment of the lateral collateral ligamentous complex of the elbow: imaging aspects in cadavers and normal volunteers

Objective  

The Lateral Collateral Ligamentous complex (LCL) is an important stabiliser of the elbow. It has a Y-shaped structure with three components. In this study, we sought to describe the ultrasound aspect of the individual components of this ligamentous complex and to evaluate the performance of ultrasound in both cadavers and in normal subjects.     

Dynamic MR imaging of osteoid osteomas: correlation of semiquantitative and quantitative perfusion parameters with patient symptoms and treatment outcome

Objective

To evaluate the relationship between multiple MR perfusion parameters and symptoms of patients with osteoid osteomas after percutaneous laser therapy.

Methods

MR perfusion studies of 20 patients diagnosed with an osteoid osteoma, treated with CT-guided percutaneous laser therapy, were retrospectively evaluated. Multiple perfusion parameters correlated with the treatment outcome and the presence of osteoid osteoma-related symptoms.

Results

There were 16 successful treatments, 6 recurrences and a significant difference in the perfusion parameters of these groups (P?<?0.0001). Patients with successful treatment demonstrated delayed progressive enhancement or no enhancement (mean time to peak?=?182 s, mean delay to the arterial peak?=?119.3 s). Patients with treatment failure demonstrated an early and steep enhancement (mean time to peak?=?78 s and mean delay to the arterial peak?=?24 s). Plasmatic volume and transfer constant values significantly changed after successful treatment (P?<?0.008). MR perfusion has a sensitivity and a specificity higher than 90 % in the detection of recurrent osteoid osteomas.

Conclusion

The identification of an early and steep enhancement with short time to peak and a short delay between the arterial and nidus peaks on MR perfusion in the postoperative setting is highly indicative of an osteoid osteoma recurrence. Key points ? Magnetic resonance perfusion is becoming widely used for several tumours. ? MR perfusion measurements correlate well with osteoid osteoma-related symptoms. ? MR perfusion has high diagnostic performance for osteoid osteoma recurrence. ? MR perfusion can improve the diagnostic confidence of osteoid osteoma recurrence.     

Linear signal hyperintensity adjacent to the subchondral bone plate at the knee on T2-weighted fat-saturated sequences: imaging aspects and association with structural lesions

Objective

To describe the association between linear T2 signal abnormalities in the subchondral bone and structural knee lesions.

Materials and methods

MR studies of patients referred for the evaluation of knee pain were retrospectively evaluated and 133 of these patients presented bone marrow edema pattern (BMEP) (study group) and while 61 did not (control group). The presence of linear anomalies of the subchondral bone on T2-weighted fat-saturated sequences was evaluated. The findings were correlated to the presence of structural knee lesions and to the duration of the patient’s symptoms. Histologic analysis of a cadaveric specimen was used for anatomic correlation.

Results

Linear T2 hyperintensities at the subchondral bone were present in 41 % of patients with BMEP. None of the patients in the control group presented this sign. When a subchondral linear hyperintensity was present, the prevalence of radial or root tears was high and that of horizontal tears was low (71.4 and 4.8 %, respectively). Sixty-nine percent of the patients with a subchondral insufficiency fracture presented a subchondral linear hyperintensity. It was significantly more prevalent in patients with acute or sub-acute symptoms (p?Conclusions The studied linear T2 hyperintensity is located at the subchondral spongiosa and can be secondary to local or distant joint injuries. Its presence should evoke acute and sub-acute knee injuries. This sign is closely related to subchondral insufficiency fractures and meniscal tears with a compromise in meniscal function.     

Correlation between tumor growth and hormonal therapy with MR signal characteristics of desmoid-type fibromatosis: A preliminary study

Purpose

To evaluate the impact of hormonal therapy on MRI characteristics of desmoid-type fibromatosis on T1-weighted, T2-weighted fat-saturated and post-contrast sequences.

Reconstructive preprosthetic surgery

The overall health of an edentulous patient may be significantly affected when added to the multiple medical and psychiatric problems common to the elderly. A patient who has a significant oral prosthetic problem may be helped with current reconstructive preprosthetic surgical techniques.     

Pseudotumoral osteochondromatosis of the hip in a soccer player

The authors present a case of pseudotumoral osteochondromatosis of the hip, interesting for its clinical and radiological features. They discuss the incidence of the sport in the pathogenesis of the loose bodies and the magnetic resonance findings.