Circulating osteogenic cells: characterization and relationship to rates of bone loss in postmenopausal women.

There is increasing evidence that osteogenic cells are present not only in bone marrow (BM) but also in peripheral blood (PB). Since staining for alkaline phosphatase (AP) identifies osteoprogenitor cells in BM, we sought to further characterize BM versus PB hematopoietic lineage negative (lin-)/AP+ cells and to compare gene expression in PB lin-/AP+ cells from postmenopausal women undergoing rapid versus slow bone loss. PB lin-/AP+ cells were smaller than their BM counterparts, and both were negative for the pan-hematopoietic marker, CD45. BM and PB lin-/AP+ cells were capable of mineralization in vitro. Using whole genome linear amplification followed by quantitative polymerase chain reaction (QPCR) analysis, we found that relative to the BM cells, PB lin-/AP+ cells expressed similar levels of a number of key osteoblast marker genes (runx2, osterix, osteopontin, OPG, periostin), consistent with the PB cells being in the osteoblastic lineage. Importantly, however, compared to the BM cells, PB lin-/AP+ cells expressed lower levels of mRNAs for AP, type I collagen, and for a panel of proliferation markers, but higher levels of osteocalcin, osteonectin, and PTHR1 mRNAs, as well as those for RANKL and ICAM-1, both of which are important in supporting osteoclastogenesis. Using microarray followed by QPCR analysis, we further demonstrated that, compared to postmenopausal women undergoing slow bone loss, PB lin-/AP+ cells from women undergoing rapid bone loss expressed lower levels of mRNAs for hydroxyprostaglandin dehydrogenase, interferon regulator factor 3, Wnt1-induced secreted protein 1, and TGFbeta2, but higher levels of the Smad3 interacting protein, zinc finger DHHC-type containing 4 and col1alpha2. These data thus demonstrate that while PB lin-/AP+ cells express a number of osteoblastic genes and are capable of mineralization, they are a relatively quiescent cell population, both in terms of cell proliferation and matrix synthesis. However, their higher expression of RANKL and ICAM-1 mRNAs as compared to BM lin-/AP+ cells suggests a role for the PB lin-/AP+ cells in regulating osteoclastogenesis that warrants further investigation. Our study also provides "proof-of-concept" for the use of PB lin-/AP+ cells in clinical-investigative studies, and identifies several pathways that could potentially regulate rates of bone loss in postmenopausal women.

Renal transplant failure due to urologic complications: Comparison of static fluid with contrast-enhanced magnetic resonance urography.

PURPOSE: Postrenal reasons of renal transplant failure can be assessed by magnetic resonance urography. This study was designed to retrospectively compare the diagnostic accuracy of static fluid (T2-)MRU compared to contrast enhanced (CE-)MRU in patients with renal transplant failure. MATERIAL AND METHODS: Thirty-five consecutive patients (14 female, 21 men; mean age 48.6 years) with renal transplant failure and sonographically detected hydronephrosis were examined both with T2-MRU as well as CE-MRU resulting in 39 MRU examinations. MRU was performed both using T2-weighted HASTE-sequence (T2-MRU) as well as Gadolinium-enhanced 3D-FLASH-sequence (CE-MRU) on a 1.5-T clinical MRI scanner (Magnetom Vision, Siemens Medical Solutions). Subjective image quality of resulting maximum intensity projection was assessed in consensus by two readers blinded to the final diagnosis, using a five point scale. MRU findings were correlated to sonography, operative results or clinical follow up. RESULTS: CE-MRU yielded a sensitivity of 85.7% (T2-MRU 76.2%), and a specificity of 83.3% (T2-MRU: 73.7%), however statistical significance was not reached. The subjective image quality was significantly better in CE-MRU. CONCLUSIONS: Only concerning subjective image quality CE-MRU proved superior to T2-MRU. Yet, there was no significant difference in diagnostic accuracy between T2- and CE-MRU. Thinking of incipient nephrogenic systemic fibrosis, T2-MRU can be used as reliable alternative in patients with decreased renal transplant function due to urological complications.

[Cerebral perfusion computerized tomography in vasospasm after subarachnoid hemorrhage: diagnostic value of MTT]. / Die zerebrale Perfusions-Computertomografie beim Vasospasmus nach Subarachnoidalblutung: Diagnostischer Wert der MTT.

PURPOSE: Analysis of the value of the perfusion parameter mean transit time (MTT) for the diagnosis of cerebral vasospasm after Subarachnoid Hemorrhage (SAH). Comparison with other perfusion parameters. An MTT threshold indicating the necessity of conventional angiography will be defined. MATERIALS AND METHODS: We analyzed the CT Perfusion (CTP) of 20 patients suffering from SAH (Fisher grading 3 and 4). In each patient a baseline examination was performed the day after treatment of the ruptured aneurysm. Follow-up was indicated for the occurrence of clinical symptoms, pathologic Doppler values or the first day after endovascular therapy. The cortical mean transit time (MTT), T (max,) cerebral blood flow (CBF) and cerebral blood volume (CBV) were calculated. A vasospasm score resulting from the Doppler values and clinical neurological symptoms was compared to MTT in the follow-up. The outcome after discharge from the intensive care unit was compared to the maximum MTT. RESULTS: 18 patients were able to be evaluated. We found parallelism between the time course of MTT and clinical symptoms in 14 of 18 patients. In 4 of 18 patients no relationship between MTT and clinical symptoms was found. There is a good correlation between the clinical outcome at the time of discharge and the MTT. Clinical symptoms occurred if the MTT was between 3.2 and 4.0 s. An MTT above 4.0 s resulted in a bad clinical outcome. 9 of 18 patients showed angiographic criteria for endovascular treatment. All those patients showed an MTT of more than 3.2 s at the time of angiography. CONCLUSION: The analysis of the cortical perfusion parameter MTT is suitable for revealing clinically relevant global and regional vasospasm. A risk potential prediction is possible. An MTT of 3.2 s indicates a conventional angiography (DSA). This should be verified using a larger number of patients.

New angiographic measurement tool for analysis of small cerebral vessels: application to a subarachnoid haemorrhage model in the rat.

INTRODUCTION: Exact quantification of vasospasm by angiography is known to be difficult especially in small vessels. The purpose of the study was to develop a new method for computerized analysis of small arteries and to demonstrate feasibility on cerebral angiographies of rats acquired on a clinical angiography unit. METHODS: A new software tool analysing grey values and subtracting background noise was validated on a vessel model. It was tested in practice in animals with subarachnoid haemorrhage (SAH). A total of 28 rats were divided into four groups: SAH untreated, SAH treated with local calcium antagonist, SAH treated with placebo, and sham-operated. The diameters of segments of the internal carotid, caudal cerebral, middle cerebral, rostral cerebral and the stapedial arteries were measured and compared to direct measurements of the diameters on magnified images. RESULTS: There was a direct correlation between the cross-sectional area of vessels measured in a phantom and the measurements acquired using the new image analysis method. The spread of repeated measurements with the new software was small compared to the spread of direct measurements of vessel diameters on magnified images. Application of the measurement tool to experimental SAH in rats showed a statistically significant reduction of vasospasm in the SAH groups treated with nimodipine-releasing pellets in comparison to all the other groups combined. CONCLUSION: The presented computerized method for analysis of small intracranial vessels is a new method allowing precise relative measurements. Nimodipine-releasing subarachnoidal pellets reduce vasospasm, but further testing with larger numbers is necessary. The tool can be applied to human angiography without modification and offers the promise of substantial progress in the diagnosis of vasospasm after SAH.

CT and MRI findings of multifocal hepatic steatosis mimicking malignancy.

We present two rare cases of multifocal hepatic steatosis as a variant of fatty liver. Multifocal hepatic steatosis can cause misleading findings in the differential diagnosis when using ultrasound and computed tomography. This case report describes the atypical findings of focal fatty liver infiltrations, which were misdiagnosed as diffuse metastatic disease. The correct diagnosis was established with magnetic resonance imaging using T1-weighted gradient-echo and T2-weighted Turbo spin-echo sequences with spectral fat suppression. Multifocal hepatic steatosis was proven by biopsy.

Anorectal manometry and defecography in the diagnosis of fecal incontinence.

We carried out anorectal manometry and defecography prospectively in 43 consecutive patients with fecal incontinence. A subgroup of 17 patients with severe incontinence was identified radiologically by a short and incompletely closed anal canal. In these patients, the anal resting pressure was significantly lower than in the rest of the group (34.9 +/- 11.4 mm Hg versus 60.0 +/- 25.7 mm Hg, respectively; p less than 0.01). The anorectal angle did not change in 24 patients during squeezing, indicating a dysfunction of the puborectalis muscle. Manometric data did not differ between this subgroup and patients with a more acute anorectal angle during voluntary sphincter contraction. This indicates that the anal pressures recorded manometrically do not reflect the function of a muscular component that is important in the maintenance of fecal continence. We conclude that anorectal manometry and defecography are complementary diagnostic tools in the investigation of patients with fecal incontinence.