Real-time Hall-effect detection of current-induced magnetization dynamics in ferrimagnets.

Measurements of the transverse Hall resistance are widely used to investigate electron transport, magnetization phenomena, and topological quantum states. Owing to the difficulty of probing transient changes of the transverse resistance, the vast majority of Hall effect experiments are carried out in stationary conditions using either dc or ac. Here we present an approach to perform time-resolved measurements of the transient Hall resistance during current-pulse injection with sub-nanosecond temporal resolution. We apply this technique to investigate in real-time the magnetization reversal caused by spin-orbit torques in ferrimagnetic GdFeCo dots. Single-shot Hall effect measurements show that the current-induced switching of GdFeCo is widely distributed in time and characterized by significant activation delays, which limit the total switching speed despite the high domain-wall velocity typical of ferrimagnets. Our method applies to a broad range of current-induced phenomena and can be combined with non-electrical excitations to perform pump-probe Hall effect measurements.

Spin-torque resonant expulsion of the vortex core for an efficient radiofrequency detection scheme.

It has been proposed that high-frequency detectors based on the so-called spin-torque diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes due to their nanoscale size, frequency tunability and large output sensitivity. Although a promising candidate for information and communications technology applications, the output voltage generated from this effect has still to be improved and, more pertinently, reduces drastically with decreasing radiofrequency (RF) current. Here we present a scheme for a new type of spintronics-based high-frequency detector based on the expulsion of the vortex core in a magnetic tunnel junction (MTJ). The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state configuration. Interestingly, this reversible effect is independent of the incoming RF current amplitude, offering a fast real-time RF threshold detector.

Understanding of Phase Noise Squeezing Under Fractional Synchronization of a Nonlinear Spin Transfer Vortex Oscillator.

We investigate experimentally the synchronization of vortex based spin transfer nano-oscillators to an external rf current whose frequency is at multiple integers, as well as at an integer fraction, of the oscillator frequency. Through a theoretical study of the locking mechanism, we highlight the crucial role of both the symmetries of the spin torques and the nonlinear properties of the oscillator in understanding the phase locking mechanism. In the locking regime, we report a phase noise reduction down to -90 dBc/Hz at 1 kHz offset frequency. Our demonstration that the phase noise of these nanoscale nonlinear oscillators can be tuned and eventually lessened, represents a key achievement for targeted radio frequency applications using spin torque devices.

Assessment of host defence mechanisms induced by Candida species.

Some species of Candida are opportunistic pathogens that can cause disease in a host immunocompromised by underlying local or systemic pathological processes. C. albicans is the species most often associated with oral lesions, but other species of Candida, including C. glabrata, C. tropicalis and C. parapsilosis, have also been isolated in the saliva of subjects with and without candidiasis. In the present study we evaluated the host defence mechanisms induced by Candida albicans and other Candida species in monocytes and oral epithelial cells in order to establish the existence of a species-specific cellular response. Our results indicated that, during Candida species infection, the epithelial cells actively participate in the host defence by producing antimicrobial peptides and proinflammatory cytokines. Moreover, in infections caused by Candida tropicalis and Candida glabrata, the host defence may be strengthened by the release of perforin and granzyme by polymorphonuclear leukocytes recruited at the site of infection.

Role of high molecular weight hyaluronic acid in postmenopausal vaginal discomfort.

AIM: Aim of the present study was to quantify the intensity of vulvovaginal symptoms before and after treatment with high molecular weight hyaluronic acid (HA), to test the tolerability and safety of the product, to evaluate the effect on the quality of life and the compliance to the treatment. METHODS: This was a double-blind randomized placebo-controlled study. In seven months we enrolled 36 post-menopausal women, equally distributed in placebo and active group. The evaluation was based on at least three atrophy-related signs and on the patient reported symptoms. After the written informed consent, the participants were instructed to apply the gel (drug or placebo) daily. Three days after the end of the treatment the patients received a final examination to evaluate the progress of symptoms, the presence of any adverse events and their correlation with the treatment. RESULTS: Self-evaluation scales and investigator evaluation showed that the vaginal dryness was significantly reduced both in placebo and in the active group; however, high molecular weight HA was the only active treatment in reducing significantly itching and burning (P<0.02 and <0.04 respectively). Both treatments significantly reduced vaginal atrophy (P<0.001), erythema (P<0.01 placebo and P<0.001 HA) and vaginal dryness (P<0.001), but HA treatment was significantly more effective on the first two symptoms. Both treatments were very well tolerated and compliance of the treatment was very high. CONCLUSION: High molecular weight HA could be effective in subjective and objective improvement of postmenopausal vaginal atrophy providing a good compliance. No adverse events occurred during the entire period of the study.

Circulating levels of cytochrome C, gamma-glutamyl transferase, triglycerides and unconjugated bilirubin in overweight/obese patients with non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease, characterized by hepatocyte apoptosis, is distinct in fatty liver and non-alcoholic steatohepatitis, the more severe form. Apoptotic cell death is caspase-dependent and associated with mitochondrial membrane depolarization and cytochrome c release. Adhering to the hypothesis that the exposure of hepatocytes to free fatty acids, resulting in increased ROS production and mitochondrial damage, is balanced by the presence of antioxidant substances, circulating levels of gamma-glutamyl transferase, cytochrome c, triglycerides and unconjugated bilirubin were explored in patients suffering from non-alcoholic fatty liver disease with different severity. One hundred and eighty-six consecutive patients who presented recent ultrasound feature of bright liver without any liver disease of known origin were enrolled, eighty-nine of whom underwent liver biopsy. Forty-five subjects were allocated on the basis of histology in fatty liver group while 44 patients formed the group with non-alcoholic steatohepatitis. A cohort of 27 young, lean, apparently healthy individuals was selected as control group. The levels of gamma-glutamyl transferase were normal or slightly increased, while unconjugated bilirubin concentrations were elevated in all the spectra of non-alcoholic fatty liver disease. Comparing the present results with relevant findings from other studies dealing with diseases characterized by apoptosis, we did not find high circulating levels of cytochrome c in non-alcoholic fatty liver disease. What is more, our patients, categorized as suffering from simple fatty liver or from the more severe non-alcoholic steatohepatitis, had similar levels of cytochrome c and gamma-glutamyl transferase, p=0.19 and 0.11. Serum triglycerides were higher in patients with non-alcoholic fatty liver disease than in the healthy group, p=0.001. These findings likely reflect a balance between oxidative stress and anti-oxidant response rather than a lack of reliability of cytochrome c as a reliable biomarker of mitochondrial damage.

Does spleen volume play a role in patients with HCV-related chronic hepatitis?

As the lymphotropism of hepatitis C virus (HCV) has already been ascertained, and in the light of the fact that the immune defense system is an organized network composed of functionally interrelated tissues, this study was carried out to verify the possible involvement of spleen in HCV-related chronic hepatitis. In this cross-sectional study we measured spleen longitudinal diameter by ultrasound, beta2-microglobulin serum levels and splenic artery resistivity index (SARI) by Doppler in 51 patients treated with standard combined (Peg-Interferon plus Ribavirin) antiviral therapy. Thirty-three patients (17 females) completed the regimen and were compared to 31 controls (16 females). The mean basal values of spleen longitudinal diameter were higher in patients with chronic hepatitis than in controls, i.e., 116 mm (9.4) versus 102.7 mm (9.3), P = 0.0001. In the same patients a significant trend towards increased spleen longitudinal diameter was found after antiviral therapy, independently of the stage of HCV-related chronic hepatitis. The median values of the beta2-microglobulin concentrations were not significantly higher in the patients with HCV-related chronic hepatitis compared to controls, i.e., 1.3 (0.5-2.6) versus 1 (0.6-1.4), P = 0.16, although during the course of therapy they were significantly increased. SARI values of HCV-related chronic hepatitis patients were different from those of controls, but were unvaried compared to values at the end of treatment. Neither spleen measurements nor serum beta2-microglobulin levels were able to predict therapeutic response to antiviral therapy. A stimulation/expansion of lymphoid tissue was found in patients with HCV-related chronic hepatitis. Such evidence raises the question whether physicians should continue to prescribe antiviral therapy in non-responders and supports the use of a new scheme (SLD plus beta2-MG) to diagnose this ongoing, apparently reversible, but nevertheless dangerous immunologic process.

Evaluation of the platelet counting by Abbott CELL-DYN SAPPHIRE haematology analyser compared with flow cytometry.

The Abbot Cell-Dyn Sapphire is a new generation haematology analyser. The system uses optical/fluorescence flow cytometry in combination with electronic impedance to produce a full blood count. Optical and impedance are the default methods for platelet counting while automated CD61-immunoplatelet analysis can be run as selectable test. The aim of this study was to determine the platelet count performance of the three counting methods available on the instrument and to compare the results with those provided by Becton Dickinson FACSCalibur flow cytometer used as reference method. A lipid interference experiment was also performed. Linearity, carryover and precision were good, and satisfactory agreement with reference method was found for the impedance, optical and CD61-immunoplatelet analysis, although this latter provided the closest results in comparison with flow cytometry. In the lipid interference experiment, a moderate inaccuracy of optical and immunoplatelet counts was observed starting from a very high lipid value.

Evaluation of the monocyte counting by two automated haematology analysers compared with flow cytometry.

The aim is to determine the monocyte count performance of the Bayer Diagnostics ADVIA120 and Coulter LH 750 automated haematology analysers and the results obtained by these two instruments were compared with those provided by Becton Dickinson FACScan flow cytometer using the combination of CD45/CD14 MoAb. Linearity and imprecision were also evaluated. The linearity of both instruments was good. Coulter LH 750 showed better precision (4.3%) than ADVIA 120 (9.0%) both within and between batch. A significant correlation (r = 0.973) was found between the LH 750 and the flow cytometry method, while a modest one was observed between the latter and the ADVIA 120 (r = 0.880). When comparing the percentage of monocytes by means of one-way anova and Tukey test, it was found that the LH 750 provided the closest results in comparison with flow cytometry, with no statistical difference between the means (mean difference MO% = 0.6); however the difference was statistically different between the ADVIA 120 and flow cytometry (mean difference MO% = -4.06). These data were confirmed by Altman-Bland and Deming regression analyses.

[Postpartum perineal assessment]. / Valutazione perineale postpartum.

BACKGROUND: To evaluate the incidence of urogenital and anorectal dysfunctions during puerperium, verify the correlation between obstetric perineal damage observed during labour and puerperal symptoms, test the efficacy of tests to evaluate perineal function in pelvic floor dysfunctions consequent to vaginal birth. METHODS: A total of 693 consecutive puerperae were recruited two months after birth. All completed a clinical and anamnestic questionnaire and underwent clinical urogynecological examination, digital test, vaginal manometry and uroflowmetric evaluation of the voluntary capacity to interrupt micturition. From a statistical point of view, persistent urinary incontinence was identified by graphic representation on frequency tables and predictive tests, and statistical "kappa" was used to evaluate the correlation between perineal function tests. RESULTS: Stress urinary incontinence (15.1%) represents the most widespread symptom, a postpartum perineal inspection provides a sufficiently accurate estimate of posterior damage, but does not identify those puerperae who will develop urinary incontinence. None of the tests used was able to predict persistant urinary incontinence. CONCLUSIONS: Postpartum perineal inspection seems to be effective in predicting anorectal dysfunctions, but is not so useful for urethro-vesical disorders. None of the diagnostic methods examined allowed a sufficiently accurate selection of those puerperae at risk.

The urine stream interruption test and pelvic muscle function in the puerperium.

OBJECTIVES: This study assesses the role of the uroflowmetric urine stream interruption test (UST) in the evaluation of postpartum pelvic floor muscle function. METHOD: Two months after vaginal delivery, 492 women who underwent a digital test, vaginal manometry, and a UST were divided into two groups: continent and incontinent. Variables were subjected to the Student's t-test and to Fisher's exact test to verify the difference between the two groups. RESULTS: Digital test and vaginal manometry results were higher in the continent group, but only the UST showed significantly different values (P=0.001). All test results of incontinent puerperae who underwent rehabilitation were significantly improved after treatment. CONCLUSIONS: UST is low cost, non-invasive, and can give objective information about pelvic floor performance after a vaginal delivery. It can be used for both routine clinical use and an outcome measure for women who undergo rehabilitation treatment.

[Magnetic resonance (MR) in endometrial carcinoma preoperative evaluation]. / Impiego della risonanza magnetica (RM) nella valutazione preoperatoria del carcinoma endometriale.

BACKGROUND: Myometrial invasion of endometrial carcinoma is an important prognostic factor because the degree of myometrial invasion is correlated with the rate of lymphnode metastases and of recurrences. The aim of the study was a preoperative evaluation of endometrial carcinoma by Magnetic Resonance (MR). METHODS: The authors present a prospective study performed on 54 cases of endometrial carcinoma collected at the Department of Gynecology and Obstetrics of the University of Trieste (Italy). All the patients were considered as Stage I after hysteroscopy and endocervical curettage. Prior to surgery all the patients underwent MR at the Department of Radiology of the University of Trieste (Italy) in order to evaluate the depth of myometrial invasion. The surgical procedure included total abdominal hysterectomy, bilateral salpingo-oophorectomy and pelvic and lomboaortic lymphadenectomy in high risk cases. Statistical evaluation was performed by Fischer's exact test. RESULTS: Statistically significant positive correlation was found (p<0.001) between MR staging and surgical staging. The sensitivity reported in our series for distinguishing between superficial disease (Stage IA and IB) and deep myometrial invasion (Stage IC) was 92%. CONCLUSIONS: Preoperative MR is helpful in selecting patients at high risk of nodal involvement and it is suggested that, although MR is considered an expensive examination, its use should be always considered before surgical treatment of patients with high surgical risk.

Evaluation of the Abbott CELL-DYN 4000 hematology analyzer.

A new generation hematology analyzer, Abbott CELL-DYN 4000 (CD 4000), capable of providing 26 parameters, including fully automated reticulocyte, nucleated RBC, blast, band, and immature granulocyte, and variant lymphocyte counts, was evaluated by using the National Committee for Clinical Laboratory Standards H20-A protocol and compared with the Bayer-Technicon H-2 analyzer, which is used routinely in our laboratory. A lipid interference experiment and a sample aging study also were performed. Linearity, carryover, and precision were within the limits established by the manufacturer, and satisfactory agreement was found with the H-2 analyzer. The evaluation of leukocyte differential counts indicated an excellent correlation with the manual reference method for neutrophils and lymphocytes, a good correlation for monocytes and eosinophils, and a poor correlation for basophils in samples with low counts; for basophil counts of 2% or higher, we found an improvement of the correlation coefficient. In the lipid interference experiment, only hemoglobin determination was influenced significantly on the CD 4000, but by using a new Abbott hemoglobin reagent, the interference was eliminated. The CBC and differential counts were stable and reportable up to at least 24 hours. Intrasample viability information on leukocytes provided a quality check on each individual specimen.

[Gynecologic infections in adolescence]. / Le infezioni ginecologiche nell'adolescenza.

BACKGROUND: Adolescence in the age bracket with the highest incidence of sexually transmitted diseases (STDs). An observational study was performed in symptomatic patients attending our Outpatient Clinic for STDs in order to evaluate the diffusion of genital infections in the adolescent population and the different epidemiological distribution compared to adults. METHODS: The incidence of these infections was compared in two groups of patients attending the clinic between April 1995 and April 1999. The first consisted of 54 teenagers (13-19 years-old) and the second, used as a control, consisted of 917 women of child-bearing age (20-40 years). All patients underwent clinical examinations and microbiological tests of vaginal secretions (bacterioscopic test on coloured plates using the Gram method, cold tests, cultural assay of bacteria and fungi, assay for (Chlamydia trachomatis, Mycoplasma spp., Neisseria gonorrhoeae, Herpes simplex virus). RESULTS: The most common genital infection in teenagers was candidosis (35% vs 23.9%), followed by bacterial vaginosis (31.9% vs 25.8%) and mixed flora vaginitis (25.9% vs 22.6%). HSV was found in 1.8% of adolescents (vs 0.6%), in selected cases, Chlamydia and Mycoplasma were present in 16.6% (vs 1.1%) and 50% (vs 28%) of teenagers respectively. CONCLUSIONS: All genital infections were more frequent in the study population of adolescents compared to the control group. The adolescent population should be the target of a serious and systematic programme of prevention in order to ward off the sequelae of early and often irresponsible sexual activity.

[Sexual behavior and adolescence]. / Costumi sessuali ed adolescenza.

BACKGROUND: Adolescence represents the period with the highest frequency of negative consequences associated with sexual activities (sexually transmitted diseases and unwanted pregnancies). An epidemiological study was carried out in symptomatic patients attending our Outpatient Clinic for Sexually Transmitted Diseases between April 1995 and April 1999 in order to evaluate the behaviour pattern of the adolescent population and identify the differences compared to the adult population. METHODS: A questionnaire was used to assess the characteristics of two groups of patients: the first consisted of 54 teenagers (13-19 years-old) and the second, the control group, consisted of 917 women aged between 20 and 40 years old. RESULTS: A high percentage of pregnancies (22.2%) and voluntary abortions (41.6%) was observed in teenagers, associated with different sexual behaviours. The age of sexual intercourse was below 15 in 44.4% of adolescents (vs 7.7% of controls), whereas 61.1% had more than one sexual partner and 20.4% had changed partners in the last 6 months (vs 7.4%). 50% of teenagers did not use any method of contraception (vs 44.2%) and barrier methods were only used by 20.4% (vs 18.4%). CONCLUSIONS: Our study confirms the existence of a high-risk behavioural pattern in the adolescent population and draws attention yet again to the need for a serious programme of prevention and sexual education which will allow adolescents to experience the discovery of their own sexuality with greater awareness and safety.

[Sexually transmitted diseases in adolescence]. / Le malattie sessualmente trasmesse in età adolescenziale.

BACKGROUND: Sexually transmitted diseases (STD) have their most incidence in adolescence. We conducted an observational study on the symptomatic patients of our STD's office to evaluate epidemiological distribution, behavioral patterns and diffusion of genital infections in teen-agers in respect of the adult population. METHODS: From april 1996 to april 1999 we studied two groups of patients: 54 teen-agers (13-19 years) and 917 women in fertile age (20-40 years). All the patients underwent to a clinical and microbiological examination of vaginal secretions (Gram slide, wet mount, cultures for bacteria, yeasts, eventually Chlamydia trachomatis, Mycoplasma spp, Neisseria gonorrhoeae, Herpes simplex virus--HSV--) and to an anamnestic and socio-epidemiological questionnaire. RESULTS: The more frequent genital infections among adolescents was vulvovaginal candidiasis (35% vs. 23.9% of adult people). HSV was found in 1.8% of teen-agers (vs. 0.6%) and when requested, Chlamydia trachomatis and mycoplasmas was found respectively in 16.6% (vs. 1.1%) and 50% (vs. 28%) in adolescents. We observed a high percentage of pregnancy (22.2%) of voluntary pregnancy interruption (41.6%) and a specific sexual behavior among teenagers. CONCLUSIONS: Our data show a particular behavioral risk pattern in the adolescence population and indicate the necessity of a serious program of prevention and sexual education that allow young people to live with more consciousness and safety their sexuality.

[Typification of HPV in clinical practice]. / Tipizzazione dell'HPV nella pratica clinica.

OBJECTIVE: To improve the sensitivity of cervical carcinoma screening and to determine the optimal management with an ASCUS Pap result we evaluated the effectiveness of combining thin layer cytologic slides (ThinPrep) and HPV DNA testing. METHODS: A total of 170 women were studied with conventional Pap smears, liquid based cytology, HPV testing and colposcopy with eventual histologic evaluation. RESULTS: The ThinPrep method yielded 12.5% more high grade lesions than did the conventional smears (and more severe diagnoses as compared to the conventional smears). HPV prevalence was significantly associated with disease status. Of 30 patients with ASCUS, HPV testing detected 100% of high grade lesions and 67% of low grade. If colposcopy had been limited to HPV+ women, 47% of case would have been spared. CONCLUSIONS: Liquid based cell collection improves sensitivity for the detection of disease. For women with ASCUS cytology, HPV DNA testing of residual specimen can identify the majority of high risk cases using a single sample.