Intranuclear expression of progesterone receptors in smooth muscle cells of renovascular fibromuscular dysplasia: a pilot study.

BACKGROUND: The pathogenesis of fibromuscular dysplasia (FMD) remains poorly understood. Yet, understanding this mechanism has taken on new urgency after recent evidence indicating that FMD is not as rare as previously thought. We speculated that hormonal receptors in the walls of dysplastic renal arteries were implicated in the pathogenesis of FMD. METHODS: We undertook a pilot prospective case-control study comparing histologic findings from renal arteries that were surgically removed in 2 patient groups. The case group included 6 samples from FMD patients who underwent surgery for stenosis or aneurysm caused by FMD. The control group included 3 FMD-free patients who underwent nephrectomy for nonvascular causes. Surgical specimens were sent to the histology laboratory. FMD was defined preoperatively using conventional radiologic criteria and was confirmed by histologic examination. RESULTS: Immunohistochemical staining detected intense progesterone receptor expression in the nuclei of smooth muscle cells in FMD patients. No progesterone receptor expression was found in the FMD-free patients. Estrogen receptor expression was not noted in the 2 groups. CONCLUSIONS: This preliminary finding may suggest that progesterone plays a key role in the pathogenesis of FMD and opens the fields of genetic and therapeutic approaches.

Automatic rebuilding and optimization of crystallographic structures in the Protein Data Bank.

MOTIVATION: Macromolecular crystal structures in the Protein Data Bank (PDB) are a key source of structural insight into biological processes. These structures, some >30 years old, were constructed with methods of their era. With PDB_REDO, we aim to automatically optimize these structures to better fit their corresponding experimental data, passing the benefits of new methods in crystallography on to a wide base of non-crystallographer structure users. RESULTS: We developed new algorithms to allow automatic rebuilding and remodeling of main chain peptide bonds and side chains in crystallographic electron density maps, and incorporated these and further enhancements in the PDB_REDO procedure. Applying the updated PDB_REDO to the oldest, but also to some of the newest models in the PDB, corrects existing modeling errors and brings these models to a higher quality, as judged by standard validation methods. AVAILABILITY AND IMPLEMENTATION: The PDB_REDO database and links to all software are available at http://www.cmbi.ru.nl/pdb_redo. CONTACT: r.joosten@nki.nl; a.perrakis@nki.nl SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Native mass spectrometry provides direct evidence for DNA mismatch-induced regulation of asymmetric nucleotide binding in mismatch repair protein MutS.

The DNA mismatch repair protein MutS recognizes mispaired bases in DNA and initiates repair in an ATP-dependent manner. Understanding of the allosteric coupling between DNA mismatch recognition and two asymmetric nucleotide binding sites at opposing sides of the MutS dimer requires identification of the relevant MutS.mmDNA.nucleotide species. Here, we use native mass spectrometry to detect simultaneous DNA mismatch binding and asymmetric nucleotide binding to Escherichia coli MutS. To resolve the small differences between macromolecular species bound to different nucleotides, we developed a likelihood based algorithm capable to deconvolute the observed spectra into individual peaks. The obtained mass resolution resolves simultaneous binding of ADP and AMP.PNP to this ABC ATPase in the absence of DNA. Mismatched DNA regulates the asymmetry in the ATPase sites; we observe a stable DNA-bound state containing a single AMP.PNP cofactor. This is the first direct evidence for such a postulated mismatch repair intermediate, and showcases the potential of native MS analysis in detecting mechanistically relevant reaction intermediates.

Congenital anomalies of inferior vena cava in young patients with iliac deep venous thrombosis.

Venous thromboembolism (VTE) in young patients is frequently associated with hereditary biological thrombophilia, autoimmune disorders, or neoplasia. Advances in venous ultrasound and contrast-enhanced computed tomography have allowed for the identification of inferior vena cava (IVC) anomalies as newly considered etiologic factor. We present two cases of VTE in young patients: the first case involves left IVC in a 22-year-old man and the second involves IVC atresia in a 39-year-old man. IVC anomalies should be identified in young patients with spontaneous VTE involving the iliac veins because they are at a high risk for thrombotic recurrence and adaptation to long periods of antithrombotic therapy.

Conservative treatment of spontaneous and isolated dissection of mesenteric arteries.

BACKGROUND: Isolated and spontaneous dissection of mesenteric arteries is a rare entity; a little more than 50 cases have been reported in medical literature. There is no therapeutic consensus concerning this type of lesion. METHODS: In this study, we report the results of our treatment based on a conservative approach. This retrospective study concerns eight patients with dissection of the celiac trunk and/or of the upper mesenteric artery (UMA) who were treated between 2002 and 2006. Because these patients were not presenting with acute intestinal ischemia diagnosed by clinical examination or paraclinical tests (medical imaging/biology) or with vital complications, they were treated with an efficient anticoagulation (heparin followed by anti-vitamin K) for 3 to 6 months. Endovascular or surgical treatment was used as the first option in patients with obvious intestinal ischemia or likely to have an arterial rupture, and also when medical treatment had failed. Clinical and radiological follow-up was at 1 month, 3 months, 6 months, and 1 year and then every year. Seven men and one woman (mean age, 48.2; age range, 38-53 years) were treated. Six patients presented with isolated dissection (celiac trunk=4, UMA=2). One patient had a celiac trunk and a UMA dissection and one had a celiac trunk and a UMA dissection along with a dissection of his two renal arteries. On entering the hospital, a patient was operated on for mesenteric ischemia related to a stenosis of the upper mesenteric artery (upper aortomesenteric bypass); a covered stent was implanted in the celiac trunk of another patient presenting with a contained rupture. RESULTS: Both patients were successfully treated. Six patients were medically treated. One of them required an aortohepatic bypass to treat an aneurysmal evolution of the celiac trunk revealed by a computed tomography scan obtained 1 month after the symptoms had begun. In one patient, the dissection remained stable on imaging. Four patients were cured, with a mean 20.1-month follow-up. CONCLUSION: Conservative treatment of spontaneous dissections of mesenteric arteries is possible when there are no complications, and it gives satisfactory results provided regular clinical and radiological checking is performed.

The GCM domain is a Zn-coordinating DNA-binding domain.

Glial cells missing (GCM) proteins form a small family of transcriptional regulators involved in different developmental processes. They contain a DNA-binding domain that is highly conserved from flies to mice and humans and consists of approximately 150 residues. The GCM domain of the mouse GCM homolog a was expressed in bacteria. Extended X-ray absorption fine structure and particle-induced X-ray emission analysis techniques showed the presence of two Zn atoms with four-fold coordination and cysteine/histidine residues as ligands. Zn atoms can be removed from the GCM domain by the Zn chelator phenanthroline only under denaturating conditions. This suggests that the Zn ions are buried in the interior of the GCM domain and that their removal abolishes DNA-binding because it impairs the structure of the GCM domain. Our results define the GCM domain as a new type of Zn-coordinating, sequence-specific DNA-binding domain.