Enhanced high harmonic generation from multiply ionized argon above 500 eV through laser pulse self-compression

By combining laser pulse self-compression and high harmonic generation within a single waveguide, we demonstrate high harmonic emission from multiply charged ions for the first time. This approach enhances the laser intensity and counteracts ionization-induced defocusing, extending the cutoff photon energy in argon above 500 eV for the first time, with higher spectral intensity and cutoff energy than He for the same input laser parameters. This Letter demonstrates a pathway for extending high harmonic emission to very high photon energies using large, multiply charged, ions with high ionization potentials.

Enhanced detection of diffusion reductions in Creutzfeldt-Jakob disease at a higher B factor

BACKGROUND AND PURPOSE

Diffusion-weighted imaging (DWI) is sensitive to the cerebral manifestations of human prion diseases. The magnitude of diffusion weighting, termed "b factor," has only been evaluated at the standard b = 1000 s/mm(2). This is the first rigorous evaluation of b = 2000 s/mm(2) in Creutzfeldt-Jakob Disease (CJD).

MATERIALS AND METHODS

We compared DWI characteristics of 13 patients with CJD and 15 healthy controls at b = 1000 s/mm(2) and b = 2000 s/mm(2). Apparent diffusion coefficients (ADC) were computed and analyzed for the whole brain by voxel-wise analysis (by SPM5) as well as in anatomically defined volumes of interest (by FSL FIRST).

RESULTS

Measured ADC was significantly lower (by approximately 5%-15%) at b = 2000 s/mm(2) than at b = 1000 s/mm(2) and significantly lower in patients than in controls. The differences between patients and controls were greater and more extensive at b = 2000 s/mm(2) than at b = 1000 s/mm(2) in the expected regions (thalamus, putamen, and caudate nucleus).

CONCLUSIONS

Because higher b factors change the absolute value of observed ADC, as well as lesion detection, care should be taken when combining studies using different b factors. While the clinical application of high b factors is currently limited by a low signal intensity-to-noise ratio, it may offer more information in questionable cases, and our results confirm and extend the central role of diffusion imaging in human prion diseases.

The European Prader-Willi Syndrome Clinical Research Database: an aid in the investigation of a rare genetically determined neurodevelopmental disorder

BACKGROUND

Prader-Willi Syndrome (PWS) is a rare genetically determined neurodevelopmental disorder with a complex phenotype that changes with age. The rarity of the syndrome and the need to control for different variables such as genetic sub-type, age and gender limits clinical studies of sufficient size in any one country. A clinical research database has been established to structure data collection and to enable multinational investigations into the development of children and adults with PWS.

METHODS

As part of a joint basic science and clinical study of PWS funded through Framework 6 of the European Union (EU), an expert multidisciplinary group was established that included clinicians involved in PWS research and clinical practice, expert database software developers, and representatives from two national PWS Associations. This group identified the key issues that required resolution and the data fields necessary for a comprehensive database to support PWS research.

RESULTS

The database consists of six 'index' entry points and branching panels and sub-panels and over 1200 data 'fields'. It is Internet-based and designed to support multi-site clinical research in PWS. An algorithm ensures that participant data are anonymous. Access to data is controlled in a manner that is compatible with EU and national laws. The database determines the assessments to be used to collect data thereby enabling the combining of data from different groups under specifically agreed conditions. The data collected at any one time will be determined by individual research groups, who retain control of the data. Over time the database will accumulate data on participants with PWS that will support future research by avoiding the need for repeat data collection of fixed data and it will also enable longitudinal studies and treatment trials.

CONCLUSION

The development of the database has proved to be complex with various administrative and ethical issues to be addressed. At an early stage, it was important to clarify the exact function of the database. It was agreed that it was primarily to support grant-funded research rather than clinical practice. The most complex issues that had to be addressed were concerned with data ownership and establishing the rules for data entry, retrieval and sharing that are compatible with data protection laws, and which are likely to be acceptable to participants and their families and to individual research groups.

Effects of pioglitazone and metformin on NEFA-induced insulin resistance in type 2 diabetes

AIMS/HYPOTHESIS

We sought to determine whether pioglitazone and metformin alter NEFA-induced insulin resistance in type 2 diabetes and, if so, the mechanism whereby this is effected.

METHODS

Euglycaemic-hyperinsulinaemic clamps (glucose approximately 5.3 mmol/l, insulin approximately 200 pmol/l) were performed in the presence of Intralipid-heparin (IL/H) or glycerol before and after 4 months of treatment with pioglitazone (n = 11) or metformin (n = 9) in diabetic participants. Hormone secretion was inhibited with somatostatin in all participants.

RESULTS

Pioglitazone increased insulin-stimulated glucose disappearance (p < 0.01) and increased insulin-induced suppression of glucose production (p < 0.01), gluconeogenesis (p < 0.05) and glycogenolysis (p < 0.05) during IL/H. However, glucose disappearance remained lower (p < 0.05) whereas glucose production (p < 0.01), gluconeogenesis (p < 0.05) and glycogenolysis (p < 0.05) were higher on the IL/H study day than on the glycerol study day, indicating persistence of NEFA-induced insulin resistance. Metformin increased (p < 0.001) glucose disappearance during IL/H to rates present during glycerol treatment, indicating protection against NEFA-induced insulin resistance in extrahepatic tissues. However, glucose production and gluconeogenesis (but not glycogenolysis) were higher (p < 0.01) during IL/H than during glycerol treatment with metformin, indicating persistence of NEFA-induced hepatic insulin resistance.

CONCLUSIONS/INTERPRETATION

We conclude that pioglitazone improves both the hepatic and the extrahepatic action of insulin but does not prevent NEFA-induced insulin resistance. In contrast, whereas metformin prevents NEFA-induced extrahepatic insulin resistance, it does not protect against NEFA-induced hepatic insulin resistance.

Ethnicity as a predictor of graft longevity and recipient mortality in heart transplantation

BACKGROUND

There is a dearth of data about the effect of donor and recipient ethnicity on survival and rejection rate after clinical heart transplantation, although the subject had been partly studied before. We compared the mortality and rejection rate among different ethnic groups at our institution.

METHODS

In retrospect, 525 consecutive donors provided cardiac allografts to adult and pediatric patients undergoing orthotropic heart transplantation at a single, urban US medical center between 2000 and 2005. Donors and recipients were categorized according to ethnicity: African American, Asian, Caucasian, Hispanic, and Others (Indian, Mediterranean/Arabic, Afghans). Donor and recipient ethnicity-as an independent factor and the interaction between them-were examined as a risk factor for mortality and rejection after heart transplantation. Mean follow-up period was 3.2+/-1.9 years (range, 0.1 to 6.6). All recipients received triple immunosuppression consisting of a calcineurin inhibitor, an antiproliferative agent, and steroids. No patients received induction immunotherapy. The end points of the study were early and late mortality, rejection rate, and rejection-free survival time.

RESULTS

The overall mortality was 17.3% (91 patients). Recipient mortality rate according to donor race was: African American, 23.1%; Asian, 11.1%; Caucasian, 18.7%; and Hispanic, 14.6%. No statistical significance was found, although the mortality differences presented. Recipient mortality with regard to recipients ethnicity was: African American, 22.2%; Asian, 6.3%; Caucasian, 18%; Hispanic, 18.9%; and others 40% (P=.048). Donor-recipient race match was not found as a risk factor influencing mortality as the matched group mortality was 17.5% comparing with the mismatched group mortality of 17.8% (P=.874). The overall rejection rate was 3.8% (20 rejection events). Rejection rate according donor race was: African American, 7.7%; Asian, 10.7%; Caucasian, 4%; and Hispanic, 1.3% (P=.027). Rejection rate with respect to recipients ethnicity was: African American, 0; Asian, 3.2%; Caucasian, 4.4%; Hispanic, 2.7%; and others, 20% with no statistical significance (P=.236). Donor recipient race match was not found as a risk factor influencing rejection rate (P=.58).

CONCLUSIONS

Recipients' ethnicity was found as a significant risk factor for mortality. Rejection rate were found higher among the African American donors and significantly lower in the Hispanic donors. Significantly lower mortality rate was found among Asian recipients. Donor-recipient race match did not influence the mortality or rejection rate.

Quasi-phase matching of high-order harmonic generation at high photon energies using counterpropagating pulses

We extend all-optical quasi-phase matching of high-order harmonic generation into spectral regions where conventional phase matching is not possible. The high laser intensities required to generate harmonics at energy >130 eV, coupled with the resulting high level of ionization, preclude conventional phase matching in all nonlinear media. Selective enhancement factors between 40 and 150 in the flux of harmonics at photon energies around 140 eV are demonstrated using a train of two counterpropagating pulses.

Four novel mutations, including the first gross deletion in TCF1, identified in HNF-4alpha, GCK and TCF1 in patients with MODY in Israel

Maturity onset diabetes of the young (MODY) is characterized by a primary defect in insulin secretion with non-ketotic hyperglycemia, monogenic autosomal dominant mode of inheritance, age at onset less than 25 years, and lack of autoantibodies. The aim of this study was to characterize the genetic basis of MODY in different ethnic groups in the Israeli population. Fifty-nine unrelated Israeli patients with MODY were assessed for mutations in the three common MODY genes: hepatocyte nuclear factor (HNF)-4alpha, glucokinase (GCK), and transcription factor 1 (TCF1). Overall, 11 mutations in 12 unrelated families were found (20.3% of patients), for a relative frequency of 1.7% for MODY1, 8.5% for MODY2, and 10.1% for MODY3. Four mutations were novel, including the first gross deletion ever described in the TCF1 gene. The low overall mutation frequency found here may suggest the involvement of other, yet unidentified, genes in the etiology of MODY in Israel.

Acute psychotic stress is associated with decreased adiponectin serum levels

OBJECTIVE

To determine the effect of acute psychotic stress on adipokine secretion in non-diabetic subjects.

RESEARCH DESIGN AND METHODS

Adiponectin, leptin, and cortisol serum levels were determined in 39 non-diabetic patients with acute psychotic stress reaction admitted to a psychiatric ward. The clinical global impression (CGI) score was used to evaluate the level of psychotic stress. Insulin sensitivity (IS) was determined by the homeostasis model assessment (HOMA). Patients were re-assessed 2 weeks after admission. During hospitalization patients were treated for variable times with either phenothiazines or thioxanthenes.

RESULTS

The mean CGI score decreased significantly with time: 5.3+/-0.8 and 2.6+/-0.8 on admission and after 2 weeks respectively (p<0.001). On admission, the mean adiponectin level was significantly lower in patients compared to normal controls: 15.3+/-8.2 mug/ml and 26+/-12.8 mug/ml, respectively (p=0.02). It increased significantly after 2 weeks to 18.2+/-10 mug/ml (p=0.003). By contrast, the leptin and cortisol levels did not change significantly. No correlation was found between the changes in individual CGI scores and adiponectin levels. However, female patients with the highest stress on admission demonstrated the lowest adiponectin levels and insulin sensitivity: p=0.002 and 0.03 respectively.

CONCLUSIONS

These data suggest a link between acute psychotic stress reaction and decreased serum adiponectin levels. Further studies are recommended to determine the strength of this association.

Probe of high-order harmonic generation in a hollow waveguide geometry using counterpropagating light

We use counterpropagating light to directly observe the coherent buildup of high harmonic generation in a hollow waveguide geometry. We measure, for the first time, coherence lengths for high photon energies that cannot be phase matched using conventional approaches. We also probe the transition through phase matching, the ionization level at which different harmonic orders are generated, and the change in the coherence length as the driving laser is depleted. These results directly prescribe the optimal structures or pulse trains required for implementing quasiphase matching.

Enhanced glucose-dependent glucagon-like peptide-1 and insulin secretion in Crohn patients with terminal ileum disease is unrelated to disease activity or ileal resection

BACKGROUND

Enhanced secretion of glucagon-like peptide-1 (GLP-1) has been reported in patients with Crohn disease (CD). However, the correlation between the enteropancreatic axis and the activity of CD remains unclear.

METHODS

Plasma glucose, insulin, GLP-1 levels and insulin sensitivity were determined before and after oral glucose tolerance tests in 13 patients with CD of the terminal ileum, in 13 patients after resection of the terminal ileum and in 7 healthy controls. Basal and stimulated insulin sensitivities were determined using the homeostasis model assessment (HOMA) and the insulin sensitivity index (ISI) methods, respectively.

RESULTS

Basal and stimulated glucose levels were comparable in patients and controls. The peak stimulated GLP-1 secretion was significantly higher in the patient group compared to controls: 12.2 +/- 1.24 pM/L and 8.1 +/- 1.72 pM/L, respectively, P=0.03. This was associated with 52% increased overall insulin secretion in the patients' group as compared to controls (P=0.007) and a higher peak insulin response: 63.5 +/- 9.69 mU/L and 41.5 +/- 6.85 mU/L for patients and controls, respectively, P=0.04. Operated patients had similar GLP-1 levels but higher peak and overall insulin secretions compared with those in non-operated patients (P=0.01). Fasting and stimulated insulin sensitivities were reduced only in patients with ileal resection as compared to controls: P=0.01 and P=0.05, respectively. No correlation was found between the CD activity index and GLP-1 or insulin secretion.

CONCLUSIONS

CD of the terminal ileum is associated with enhanced glucose-dependent GLP-1 secretion, which is unrelated to disease activity or ileal resection.

Random-phase solitons in nonlinear periodic lattices

We predict the existence of random phase solitons in nonlinear periodic lattices. These solitons exist when the nonlinear response time is much longer than the characteristic time of random phase fluctuations. The intensity profiles, power spectra, and statistical (coherence) properties of these stationary waves conform to the periodicity of the lattice. The general phenomenon of such solitons is analyzed in the context of nonlinear photonic lattices.

[Ductal carcinoma in situ]

Ductal carcinoma in situ (DCIS) is now found far more frequently because of mammograms, appearing with microcalcifications. Actually, it is probably very common. Premalignant lesions such as ductal carcinoma in situ are demonstrating the truth of a major concept: that there are lesions within the breast that may be locally removed and controlled before the development of metastatic disease. This article, presents the current management of ductal carcinoma in situ.

The clinical impact of 18F-FDG gamma PET in patients with recurrent well differentiated thyroid carcinoma

The therapeutic approach to recurrent well-differentiated thyroid cancer is based on the detection of active disease. While a measured increase of thyroglobulin level in an ablated patient is highly suggestive of recurrence, localization of the tumour is necessary for adequate treatment planning. A whole body scan with 131I yields false negative results in the presence of non-iodophyllic foci of disease. Hypermetabolic foci of differentiated thyroid carcinoma can be detected by gamma PET with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG). This study retrospectively evaluated the therapeutic impact of the 18F-FDG scan in patients with suspected recurrent thyroid carcinoma in whom the iodine scan was negative. Twenty patients (five male, 15 female) aged 19-77 years, were suspected of having recurrent thyroid carcinoma due to elevated thyroglobulin levels and/or palpable neck findings. All whole body iodine scans obtained with diagnostic doses (74-148 MBq (2-4 mCi) of 131I), were reported normal, i.e., no iodophyllic foci were detected. Whole body gamma positron emission tomography (PET) imaging was performed in fasting patients following i.v. administration of 370 MBq (10 mCi) 18F-FDG, with a strict 1 h immobilization post-injection. Gamma PET results were validated either by anatomical imaging, repeat iodine scanning after administration of a therapeutic dose (at least 3,700 MBq (100 mCi) of 131I) or surgery. The impact of the FDG scan on patient management was evaluated by the referring physicians. Positive gamma PET results confirmed the presence of active disease in 14/15 patients. One false positive finding (fibrosis) and one false negative (carcinoid) were reported. Localization of hypermetabolic foci supported treatment decisions in 10 patients, and significantly altered therapeutic management in six others. Treatment was withheld in four patients with negative findings. The clinical impact of the scan in this patient group is similar to that reported in the literature and justifies its future implementation.

Use of hormone replacement therapy by menopausal women in six family-practice teaching clinics in Israel

BACKGROUND

The necessity of hormone replacement therapy (HRT) remains a controversial subject, but guidelines suggest that the subject be discussed with all menopausal women.

AIM

To determine the rate of HRT use among women cared for in family-practice, university-affiliated teaching clinics.

METHODS

Physicians from six family-practice teaching clinics enrolled all menopausal patients, aged between 50 and 70 years, registered in their practice. A detailed questionnaire was completed regarding demographic and health variables, gynecological history and the nature of HRT use.

RESULTS

In total, 682 women were invited to participate in the study; 587 (86%) participated. Some 74% of the women were married, 64% were secular and 43% stated that they performed regular exercise. Current HRT use was reported by 156 women (26.6%). Most women (83%) had been treated for over 1 year. Common indications for starting treatment were hot flushes (75%), and routine recommendation by their physician (68%). Eighty-three (14%) women were past HRT users. It was stated by 45% of never-users that HRT had never been offered to them. Current users of HRT were found to be younger than non-users (mean age 58.2 years vs. 61.5 years, p < 0.0001), more secular than traditional or religious (p < 0.0001) with more years of formal education (p < 0.0001), and more likely to be of Western or European ("Ashkenazi") origin (p < 0.0001). Current HRT users reported fewer chronic illnesses than did non-users (p = 0.001); they were more likely to report being engaged in regular exercise (p < 0.002) and were less likely to be obese (p < 0.005). In a multiple regression model, HRT use was associated with more years of formal education and a secular identity.

CONCLUSION

Our study found a higher proportion of women using HRT than in other Israeli studies. HRT use was more prevalent among women with improved health status and higher socioeconomic status. The most common reason given for not using HRT was that a physician had not raised the subject, indicating that physician-related factors might contribute to using HRT. Thus, comparing HRT prescribing rates in non-teaching clinics should clarify this factor.

Neuronal overexpression of "readthrough" acetylcholinesterase is associated with antisense-suppressible behavioral impairments

Molecular origin(s) of the diverse behavioral responses to anticholinesterases were explored in behaviorally impaired transgenic (Tg) FVB/N mice expressing synaptic human acetylcholinesterase (hAChE-S). Untreated hAChE-S Tg, unlike naïve FVB/N mice, presented variably intense neuronal overexpression of the alternatively spliced, stress-induced mouse "readthrough" mAChE-R mRNA. Both strains displayed similar diurnal patterns of locomotor activity that were impaired 3 days after a day-to-night switch. However, hAChE-S Tg, but not FVB/N mice responded to the circadian switch with irregular, diverse bursts of increased locomotor activity. In social recognition tests, controls displayed short-term recognition, reflected by decreased exploration of a familiar, compared to a novel juvenile conspecific as well as inverse correlation between social recognition and cortical and hippocampal AChE specific activities. In contrast, transgenics presented poor recognition, retrievable by tetrahydroaminoacridine (tacrine, 1.5 mg kg(-1)). Tacrine's effect was short-lived (24 h) suppression of the abnormal social recognition pattern in transgenics. Efficacy of antisense treatment was directly correlated with AChE-R levels and the severity of the impaired phenotype, being most apparent in transgenics presenting highly abnormal pre-treatment behavior. These findings demonstrate that neuronal AChE-R overproduction is involved in various behavioral impairments and anticholinesterase responses, and point to the antisense strategy as a potential approach for re-establishing cholinergic balance.

Vancomycin versus cefazolin prophylaxis for cardiac surgery in the setting of a high prevalence of methicillin-resistant staphylococcal infections

OBJECTIVE

This study was undertaken to compare the efficacy of vancomycin prophylaxis with that of cefazolin in preventing surgical site infections in a tertiary medical center with a high prevalence of methicillin-resistant staphylococcal infections.

METHODS

All adult patients (> or = 18 years) scheduled for cardiac surgery requiring sternotomy were randomly assigned to receive vancomycin (1 g every 12 hours) or cefazolin (1 g every 8 hours). Prophylaxis was started during the induction of anesthesia and continued for only 24 hours. Patients were followed up for at least 30 days (1 year for those receiving a cardiac implant). Surgical site infections were stratified according to the National Nosocomial Infections Surveillance System risk index.

RESULTS

Of the 885 patients included in the study, 452 received vancomycin and 433 received cefazolin. The overall surgical site infection rates were similar in the two groups (43 cases in the vancomycin group, 9.5%, vs 39 cases in the cefazolin group, 9.0%, P =.8). Superficial and deep incisional surgical site infection rates were also similar in the two groups. There was a trend toward more frequent organ-space infections and infections with beta-lactam-resistant organisms among patients receiving cefazolin, but this trend did not reach statistical significance. In contrast, surgical site infections caused by methicillin-susceptible staphylococci were significantly more common in the vancomycin group (17 cases, 3.7%, vs 6 cases, 1.3%, P =.04). The durations of postoperative hospitalization and the mortalities were similar in the two groups.

CONCLUSIONS

This trial suggests that vancomycin and cefazolin have similar efficacy in preventing surgical site infections in cardiac surgery.

The pro-apoptotic function of death-associated protein kinase is controlled by a unique inhibitory autophosphorylation-based mechanism

Death-associated protein kinase is a calcium/calmodulin serine/threonine kinase, which positively mediates programmed cell death in a variety of systems. Here we addressed its mode of regulation and identified a mechanism that restrains its apoptotic function in growing cells and enables its activation during cell death. It involves autophosphorylation of Ser(308) within the calmodulin (CaM)-regulatory domain, which occurs at basal state, in the absence of Ca(2+)/CaM, and is inversely correlated with substrate phosphorylation. This type of phosphorylation takes place in growing cells and is strongly reduced upon their exposure to the apoptotic stimulus of C(6)-ceramide. The substitution of Ser(308) to alanine, which mimics the ceramide-induced dephosphorylation at this site, increases Ca(2+)/CaM-independent substrate phosphorylation as well as binding and overall sensitivity of the kinase to CaM. At the cellular level, it strongly enhances the death-promoting activity of the kinase. Conversely, mutation to aspartic acid reduces the binding of the protein to CaM and abrogates almost completely the death-promoting function of the protein. These results are consistent with a molecular model in which phosphorylation on Ser(308) stabilizes a locked conformation of the CaM-regulatory domain within the catalytic cleft and simultaneously also interferes with CaM binding. We propose that this unique mechanism of auto-inhibition evolved to impose a locking device, which keeps death-associated protein kinase silent in healthy cells and ensures its activation only in response to apoptotic signals.