Three‐dimensional imaging and analysis of human cartilage degeneration using Optical Coherence Tomography

Optical Coherence Tomography (OCT) is an evolving imaging technology allowing non‐destructive imaging of cartilage tissue at near‐histological resolution. This study investigated the diagnostic value of real time 3‐D OCT in comparison to conventional 2‐D OCT in the comprehensive grading of human cartilage degeneration. Fifty‐three human osteochondral samples were obtained from eight total knee arthroplasties. OCT imaging was performed by either obtaining a single two‐dimensional cross‐sectional image (2‐D OCT) or by collecting 100 consecutive parallel 2‐D OCT images to generate a volumetric data set of 8 × 8 mm (3‐D OCT). OCT images were assessed qualitatively according to a modified version of the DJD classification and quantitatively by algorithm‐based evaluation of surface irregularity, tissue homogeneity, and signal attenuation. Samples were graded according to the Outerbridge classification and statistically analyzed by one‐way ANOVA, Kruskal Wallis and Tukey's or Dunn's post‐hoc tests. Overall, the generation of 3‐D volumetric datasets and their multiple reconstructions such as rendering, surface topography, parametric, and cross‐sectional views proved to be of potential diagnostic value. With increasing distance to the mid‐sagittal plane and increasing degeneration, score deviations increased, too. In conclusion, 3‐D imaging of cartilage with image analysis algorithms adds considerable potential diagnostic value to conventional OCT diagnostics. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:651–659, 2015.     

Transsacral screw safe zone size by sacral segmentation variations

Variations in sacral segmentation may preclude safe placement of transsacral screws for posterior pelvis fixation. We developed a novel automated 3D technique to determine the safe zone size for transsacral screws in the upper two sacral segments in 526 adult pelvis computed tomography scans. Safe zone sizes were then compared by gender and sacral segmentation variations (number of neuroforamen and the presence/absence of lumbosacral transitional vertebrae, ±LSTV). Ten millimeters was used as the safety threshold for a large screw. 3 (0.6%), 366 (70%), and 157 (30%) sacra had 3, 4, or 5 neuroforamen, respectively. Eighty‐eight (17%) were +LSTV. Safe zone size depended on gender, number of neuroforamen in −LSTV sacra and presence of LSTV (p < 0.001) but not on the uni‐ or bilateral nature of the LSTV. 17% of −LSTV sacra were below the safety threshold in S1, 27% in S2, whereas 3% of +LSTV sacra were below in S1, 74% in S2. Of −LSTV sacra that cannot take an S1 screw safely, 77% can do so in S2, leaving only 4% of sacra that cannot accommodate a screw safely in either upper segment. The results demonstrate a predictable pattern of safe zone size based on gender and sacral segmentation variations. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:277–282, 2015.

     

SDF‐1/CXCR4/CXCR7 is pivotal for vascular smooth muscle cell proliferation and chronic allograft vasculopathy

Chronic rejection remains a major obstacle in transplant medicine. Recent studies suggest a crucial role of the chemokine SDF‐1 on neointima formation after injury. Here, we investigate the potential therapeutic effect of inhibiting the SDF‐1/CXCR4/CXCR7 axis with an anti‐SDF‐1 Spiegelmer (NOX‐A12) on the development of chronic allograft vasculopathy. Heterotopic heart transplants from H‐2bm12 to B6 mice and aortic transplants from Balb/c to B6 were performed. Mice were treated with NOX‐A12. Control animals received a nonfunctional Spiegelmer (revNOX‐A12). Samples were retrieved at different time points and analysed by histology, RT‐PCR and proliferation assay. Blockade of SDF‐1 caused a significant decrease in neointima formation as measured by intima/media ratio (1.0 ± 0.1 vs. 1.8 ± 0.1, P < 0.001 AoTx; 0.35 ± 0.05 vs. 1.13 ± 0.27, P < 0.05 HTx). In vitro treatment of primary vascular smooth muscle cells with NOX‐A12 showed a significant reduction in proliferation (0.42 ± 0.04 vs. 0.24 ± 0.03, P < 0.05). TGF‐β, TNF‐α and IL‐6 levels were significantly reduced under SDF‐1 inhibition (3.42 ± 0.37 vs. 1.67 ± 0.33, P < 0.05; 2.18 ± 0.37 vs. 1.0 ± 0.39, P < 0.05; 2.18 ± 0.26 vs. 1.6 ± 0.1, P < 0.05). SDF‐1/CXCR4/CXCR7 plays a critical role in the development of chronic allograft vasculopathy (CAV). Therefore, pharmacological inhibition of SDF‐1 with NOX‐A12 may represent a therapeutic option to ameliorate chronic rejection changes.     

The protein product of the het-s heterokaryon incompatibility gene of the fungus Podospora anserina behaves as a prion analog

The het-s locus of Podospora anserina is a heterokaryon incompatibility locus. The coexpression of the antagonistic het-s and het-S alleles triggers a lethal reaction that prevents the formation of viable heterokaryons. Strains that contain the het-s allele can display two different phenotypes, [Het-s] or [Het-s*], according to their reactivity in incompatibility. The detection in these phenotypically distinct strains of a protein expressed from the het-s gene indicates that the difference in reactivity depends on a posttranslational difference between two forms of the polypeptide encoded by the het-s gene. This posttranslational modification does not affect the electrophoretic mobility of the protein in SDS/PAGE. Several results suggest a similarity of behavior between the protein encoded by the het-s gene and prions. The [Het-s] character can propagate in [Het-s*] strains as an infectious agent, producing a [Het-s*] → [Het-s] transition, independently of protein synthesis. Expression of the [Het-s] character requires a functional het-s gene. The protein present in [Het-s] strains is more resistant to proteinase K than that present in [Het-s*] mycelium. Furthermore, overexpression of the het-s gene increases the frequency of the transition from [Het-s*] to [Het-s]. We propose that this transition is the consequence of a self-propagating conformational modification of the protein mediated by the formation of complexes between the two different forms of the polypeptide.     

Studies on the mechanism of accumulation of cholesterol in the gallbladder mucosa. Evidence that sterol 27-hydroxylase is not a pathogenetic factor

BACKGROUND/AIMS: Cholesterolosis is characterized by accumulation of esterified cholesterol in human gallbladder mucosa. The present study aimed at investigating possible pathogenetic factors for cholesterolosis. The hypothesis was tested that a reduced sterol 27-hydroxylase or an increased amount of ACAT-1 enzyme may be of importance. METHODS: Gall bladder mucosa and bile were obtained from patients with cholesterol gallstones undergoing cholecystectomy (30 with and 43 without cholesterolosis). RESULTS: In cholesterolosis, the gall bladder mucosa was characterized by a several-fold increase in esterified cholesterol and normal content of free cholesterol. The amount of ACAT-1 protein, measured by immunoblotting, was similar in patients with and without cholesterolosis. The level of 27-hydroxycholesterol in gallbladder mucosa was elevated sevenfold as compared with cholesterol in patients with cholesterolosis. Most (87%) of this oxysterol was esterified and the accumulation is most probably secondary to the higher total amount of cholesterol in the cells. Patients with cholesterolosis had normal levels of both sterol 27-hydroxylase mRNA (real time polymerase chain reaction) and protein (immunoblotting). The enzymatic activity of the sterol 27-hydroxylase in gallbladder mucosa was normal or increased in cholesterolosis. CONCLUSIONS: The pathogenesis of cholesterolosis may be multifactorial, but is not caused by reduced efflux of cholesterol due to a defect sterol 27-hydroxylase mechanism.     

MDR1 gene expression and drug resistance of AML cells

We investigated the cellular drug resistance to aclarubicin (Acla), cytosine arabinoside (Ara-C), daunorubicin (Dau), doxorubicin (Dox), etoposide (Etop) and mitoxantrone (Mitox) using the MTT assay at time of disease presentation in 93 cases of acute myeloid leukaemia (AML). In 31 cases we concomitantly investigated MDR1 (multiple drug resistance 1 gene) expression (semi-quantitative competitive RT-PCR) of the leukaemic cells. Drug resistance towards Dau, Dox and Etop was correlated to the MDR1 expression of the AML cells ( P  < 0.05) with high MDR1 expression being associated with high drug resistance towards these drugs. Although the data did not allow firm conclusions to be drawn on the correlation between MDR1 expression and drug resistance towards Ara-C and Mitox, the drug resistance towards Acla clearly was not correlated to, or dependent on, the MDR1 expression level of the AML blast cells. In addition, when examining the cross-activities among the six drugs distinct patterns emerged. Thus, high to very high degrees of cross-activity were found to exist between Dau, Dox, Etop and Mitox, whereas Ara-C had moderate cross-activity with the other drugs except Acla, which showed absent to moderate cross-activity with the other drugs. We conclude that MDR1 gene expression is of significance for cellular drug resistance towards specific (MDR1-related) drugs in AML, whereas it is not of significance regarding drug resistance towards other drugs, which is the case with the anthracycline Acla. We suggest that in the place of other more or less complicated ways to circumvent MDR1-mediated drug resistance, Acla may be used to replace Dau, Dox and other MDR1-related drugs if proven as potent as the drug it is to substitute.     

Norethisterone Treatment, a Major Risk-Factor for Veno-Occlusive Disease in the Liver After Allogeneic Bone Marrow Transplantation

In this single-center study, we retrospectively analyzed incidenceand risk factors for hepatic veno-occlusive disease (VOD) in 249 consecutive patients who underwent allogeneic hematopoietic stem celltransplantation between January 1990 and June 1995. Twenty-four of the249 transplanted patients developed VOD. The probabilities ofdeveloping VOD were 17% among women and 7% in men (P = .01). In women treated with norethisterone, the incidence was 27%compared with 3% in women without this treatment (P = .007).One-year survival rates were 17% and 73% in patients with (n = 24)or without VOD (n = 225), respectively. The use of heparin prophylaxis (100 IE/kg/24 hours for 1 month) did not alter the incidence or 1-year mortality of VOD. In multivariate analysis, thefollowing risk factors were significant: norethisterone treatment (P < .001), bilirubin >26 µmol/L before bone marrowtransplantation (BMT) (P = .002), one HLA-antigen mismatch(P = .003), previous abdominal irradiation (P = .02), and conditioning with busulphan (P = .02). Ourconclusion is that norethisterone treatment should not be used inpatients undergoing BMT and heparin prophylaxis did not affect theincidence or mortality of VOD.     

Clinical and psychological correlates of quality-of-life in polycystic ovary syndrome

OBJECTIVE: Polycystic ovary syndrome (PCOS) has been shown to cause a reduction in quality of life. This study examines the extent of different PCOS symptoms on quality-of-life, psychosocial well-being and sexual satisfaction. METHODS: Complete metabolic, hormonal, clinical and psychosocial data were obtained from a total of 120 women with PCOS. Patients were compared with 50 healthy women to establish reductions in quality-of-life and emotional well-being. In addition, the correlation between psychosocial variables and the major clinical PCOS features obesity (body mass index (BMI)), excessive body hair (hirsutism score), acne, hyperandrogenism (serum testosterone levels), disturbed insulin regulation (area under the insulin response curve and homeostasis model assessment of insulin resistance), menstrual cycle disturbances and infertility were analyzed. RESULTS: PCOS patients showed significant reductions in quality-of-life, increased psychological disturbances, and decreased sexual satisfaction when compared with healthy controls. BMI and hirsutism scores, but not the presence of acne, were associated with physical aspects of quality-of-life and sexual satisfaction. No clear effect of androgens or insulin resistance on psychosocial variables was detected. Similarly, the type of menstrual cycle disturbances or infertility had no impact on psychological well-being. CONCLUSION: In PCOS, changes in appearance, particularly obesity and hirsutism, reduce physical dimensions of quality-of-life and decrease sexual satisfaction. The role of biochemical, endocrine and metabolic parameters as well as menstrual irregularities and infertility appeared to be less important. Clinicians should pay attention to the psychosocial dimensions of PCOS on an individual basis, regardless of symptom severity or treatment response.