Communication: Chemisorption of muonium on gold nanoparticles: A sensitive new probe of surface magnetism and reactivity.

Chemisorption of muonium onto the surface of gold nanoparticles has been observed. Muonium (µ+e-), a light hydrogen-like atom, reacts chemically with uncapped 7 nm gold nanoparticles embedded in mesoporous silica (SBA-15) with a strong temperature-dependent rate. The addition rate is fast enough to allow coherent spin transfer into a diamagnetic muon state on the nanoparticle surface. The muon is well established as a sensitive probe of static or slowly fluctuating magnetic fields in bulk matter. These results represent the first muon spin rotation signal on a nanoparticle surface or any metallic surface. Only weak magnetic effects are seen on the surface of these Au nanoparticles consistent with Pauli paramagnetism.

Precise repair of mPing excision sites is facilitated by target site duplication derived microhomology.

BACKGROUND: A key difference between the Tourist and Stowaway families of miniature inverted repeat transposable elements (MITEs) is the manner in which their excision alters the genome. Upon excision, Stowaway-like MITEs and the associated Mariner elements usually leave behind a small duplication and short sequences from the end of the element. These small insertions or deletions known as "footprints" can potentially disrupt coding or regulatory sequences. In contrast, Tourist-like MITEs and the associated PIF/Pong/Harbinger elements generally excise precisely, returning the genome to its original state. The purpose of this study was to determine the mechanisms underlying these excision differences, including the role of the host DNA repair mechanisms. RESULTS: The transposition of the Tourist-like element, mPing, and the Stowaway-like element, 14T32, were evaluated using yeast transposition assays. Assays performed in yeast strains lacking non-homologous end joining (NHEJ) enzymes indicated that the excision sites of both elements were primarily repaired by NHEJ. Altering the target site duplication (TSD) sequences that flank these elements reduced the transposition frequency. Using yeast strains with the ability to repair the excision site by homologous repair showed that some TSD changes disrupt excision of the element. Changing the ends of mPing to produce non-matching TSDs drastically reduced repair of the excision site and resulted in increased generation of footprints. CONCLUSIONS: Together these results indicate that the difference in Tourist and Stowaway excision sites results from transposition mechanism characteristics. The TSDs of both elements play a role in element excision, but only the mPing TSDs actively participate in excision site repair. Our data suggests that Tourist-like elements excise with staggered cleavage of the TSDs, which provides microhomology that facilitates precise repair. This slight modification in the transposition mechanism results in more efficient repair of the double stranded break, and thus, may be less harmful to host genomes by disrupting fewer genes.

Restricted expression of karyopherin alpha mRNA in the sea urchin suggests a role in neurogenesis.

Karyopherin alpha (KAP-α) proteins are critical for the transport of many molecules into the nucleus. In this study, we identified three members of the KAP-α family in the sea urchin Lytechinus variegatus and described the developmental expression of these proteins. Although many importins are assumed to have ubiquitous expression, we found that all three genes were differentially expressed. Both LvKPNA1/5/6 and LvKPNA3/4 accumulated at high levels during cleavage, exhibiting cyclic expression as cells divided. By the blastula and gastrula stages expression decreased, remaining highest in the vegetal plate and archenteron, and by the prism/pluteus stages expression was restricted to the oral surface and gut. Expression of a third KAP-α gene, LvKPNA2/7, was examined in embryos from the mesenchyme blastula to pluteus stages. LvKPNA2/7 mRNA is present in vegetal cells of the mesenchyme blastula and, during gastrulation, it is localized to the archenteron and appears in additional groups of ectodermal cells. Prism/pluteus stage embryos expressed LvKPNA2/7 in the gut and scattered distribution of transcripts in the ciliary band resembled expression patterns of neural cells. We hypothesize that LvKPNA2/7 maintains pluripotency in the neural precursors prior to activation of neural differentiation and believe that this study is an important first step in an effort to better understand the roles of importins during embryogenesis.

Predicting the result of nerve conduction tests in carpal tunnel syndrome using a questionnaire.

We performed a study to determine whether the results of a questionnaire could be used to predict the results of nerve conduction tests in patients with suspected carpal tunnel syndrome. Two hundred and eleven consecutive patients underwent electrophysiological testing, and completed the questionnaire designed by Kamath and Stothard. Two questionnaire threshold scores were identified, which classified with high sensitivity and high specificity those patients who had normal, and abnormal nerve conduction tests respectively. Patients who scored greater than 6 on the questionnaire could be classified with 87% specificity as having abnormal tests, and patients scoring below 3 on the questionnaire could be classified with 87% sensitivity as having normal studies. We suggest therefore that patients who score above 6, or below 3 on this questionnaire may not need to be referred for nerve conduction tests, as the result can be predicted with adequate accuracy.

Can self-reported height and weight be used to calculate 10 year risk of osteoporotic fracture?

OBJECTIVES: 1) To determine the magnitude of error between self reported height and weight and measured height and weight, 2) To measure what affect this has on calculating 10 year probability of osteoporotic fracture using the World Health Organisation Fracture Risk Assessment Tool (FRAX®). DESIGN: Data collection from a nurse led community osteoporosis clinic. PARTICIPANTS: 214 post-menopausal women with at least one risk factor for osteoporosis. MEASUREMENTS: Self reported and measured height and weight, risk factors for osteoporosis, demographic details, and 10 year probability of hip fracture or any major osteoporotic fracture as measured by FRAX®. RESULTS: Patients over-reported their height by a mean (95% confidence interval) of 2.8 (2.3-3.2) cm and under reported their weight by a mean of 2.1 (1.3-2.6) Kg. The resulting underestimation of body mass index was 1.8 (1.3-2.0) units. Using self reported height and weight resulted in a significant over-estimation of 10 year risk of hip fracture and any major osteoporotic fracture when compared to measured height and weight; Median 10 probability of hip fracture 3.75% Vs 3.25% (p < 0.001 ), median 10 year probability of any major osteoporotic fracture 15% Vs. 14% (p < 0.001). CONCLUSION: When calculating 10 year risk of fracture using the FRAX on line assessment tool, measured height and weight should be used instead of self-reported height and weight.

The diagnostic conundrum and liver transplantation outcome for combined hepatocellular-cholangiocarcinoma.

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare primary liver malignancy with mixed hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) histological features. It is almost impossible to obtain an accurate, preoperative noninvasive diagnosis of cHCC-CC with tumor markers or cross-sectional abdominal imaging due to the mixed histological features. Despite these difficulties, accurate cHCC-CC diagnosis remains an important goal with prognostic significance. In our study, we retrospectively reviewed the tumor markers: AFP and CA 19-9, and cross-sectional liver imaging, in light of liver explant findings, to identify and characterize cHCC-CC features followed by liver transplantation (LT) outcome analysis. The results from this 12 patient cohort failed to identify characteristic features for cHCC-CC. None of the imaging features helped to identify the cHCC-CC tumor and they mimicked either HCC or CC, depending on the degree of glandular differentiation expressed histologically. In our cHCC-CC LT recipients, the 1-, 3- and 5-year cumulative survival probabilities were 79%, 66% and 16%, respectively with a 5-year survival comparable to or better than LT for intrahepatic CC but poorer than LT for HCC following the Milan criteria. Conceivably explained by its cholangiocarcinoma component the LT outcome for this rare and hard to diagnose tumor appears poor.

Benign metastasizing leiomyoma responsive to megestrol: case report and review of the literature.

Benign metastasizing leiomyoma (BML) is an unusual condition typically treated by surgical resection and hormonal therapy. A 37-year-old woman presented with dyspnea 6 years after uterine myomectomy. Computed tomographic scans showed pelvic and right-sided lung masses. Total abdominal hysterectomy and right salpingo-oophorectomy revealed only leiomyomas and benign ovarian cysts. Thoracotomy revealed multiple nodules consistent with leiomyomas. Estrogen and progesterone receptors on lung and uterine tissue were positive. A 21- x 18-mm residual area of neoplasm in the lung completely resolved 3 months after treatment with megestrol. The patient remains free of disease 3 years after lung resection. We present a rare case of BML in which the lung neoplasm responded to megestrol alone in the setting of intact ovarian function.

Influence of diabetes on peripheral bone mineral density in men: a controlled study.

The aims of the study were to (1) compare peripheral bone mineral density (BMD) in men with diabetes to peripheral BMD in non-diabetic men, and (2) explore factors which may predict BMD in diabetic men. Ninety men with type 2 diabetes and 35 men with type 1 diabetes were randomly selected for participation via a computerised database. Fifty healthy males were also recruited. All patients had peripheral BMD measured by dual energy Xray absorptiometry (DEXA) at the non-dominant distal radius. Information on a number of clinical parameters was obtained by direct questioning, and from patient case notes. The mean age (95% confidence interval (CI)) of the type 1 diabetic group, type 2 diabetic group and control group were, respectively: 49.3 years (44.6-53.9), 62.8 years (60.7-64.8) and 38.5 (34.9-42.1) years. Median (95% CI) Z-scores for the three groups were: -0.18 (-0.68 to +0.32), +0.19 (-0.14 to +0.49) and -0.02 (-0.4 to +0.31), respectively (p=not significant). Only body mass index (BMI) was correlated with BMD in the type 1 diabetic group, and only BMI and age were correlated with BMD in type 2 diabetics. There was no correlation between BMD and glycosylated haemoglobin concentration (HbA(1)c), disease duration or presence of microvascular or macrovascular complications in either of the diabetic groups. We did not find any significant difference in peripheral BMD between patients with type 1 diabetes, type 2 diabetes and controls.

Utility of magnetic resonance imaging in evaluating inflatable penile prosthesis malfunction and complaints.

The introduction of oral pharmacotherapy dramatically changed practice patterns in erectile dysfunction. The direct effect was to decrease the numbers of patients seeking penile implants; an indirect effect has been the changing ratio of new, to re-do operations. Patients seeking replacement inflatable penile prosthesis (IPP) surgery pose challenges both in diagnosis and management; in very select cases preoperative MRI can be useful in the evaluation of the patient's complaint and in planning operative management. Imaging can supplement the physical exam; in certain cases imaging will reveal: crural herniation, corporal distortion, corporal fibrosis, and hardware migration. Inflatable penile prosthesis has a high rate of satisfaction for patients (89%) and partners (70%). The principal reasons for dissatisfaction are penile shortening, pain and frustration with reoperation. If pain is not due to infection, it may be secondary to malpositioning, improper sizing, cylinder cross-overs, or herniation. After one or more reoperations, penile distortion may occur secondary to tunica albugenia thinning or fibrosis. A series of cases will be presented to highlight the utility of MRI for IPP problems, define normal appearance and abnormal appearance of penile hardware. Careful collaboration between the Urologist and Radiologist in the review and final dictation of these cases is warranted to properly document problems and to plan device replacement/penile reconstruction.