Search for Lepton Number and Flavor Violation in K^{+} and π^{0} Decays

Searches for the lepton number violating K^{+}→π^{-}μ^{+}e^{+} decay and the lepton flavor violating K^{+}→π^{+}μ^{-}e^{+} and π^{0}→μ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K^{+}→π^{-}μ^{+}e^{+})<4.2×10^{-11}, B(K^{+}→π^{+}μ^{-}e^{+})<6.6×10^{-11} and B(π^{0}→μ^{-}e^{+})<3.2×10^{-10}. These results improve by 1 order of magnitude over previous results for these decay modes.

Intravenous immunoglobulin as an adjunct therapy in persisting heparin-induced thrombocytopenia

Heparin induced thrombocytopenia (HIT) is a serious adverse drug reaction caused by transient antibodies against platelet factor 4 (PF4)/heparin complexes, resulting in platelet activation and potentially fatal arterial and/or venous thrombosis. Most cases of HIT respond to cessation of heparin and administration of an alternative non-heparin anticoagulant, but there are cases of persisting HIT, defined as thrombocytopenia due to platelet activation/consumption for greater than seven days despite standard therapy. These patients remain at high risk for thrombotic events, which may result in limb-loss and mortality. Intravenous immunoglobulin (IVIg) has been proposed as an adjunct therapy for these refractory cases based on its ability to saturate FcγRIIa receptors on platelets, thus preventing HIT antibody binding and platelet activation. We describe 2 cases of persisting HIT (strongly positive antigen and functional assays, and persisting thrombocytopenia >7 days) with rapid clinical response to IVIg. We performed in-vitro experiments to support IVIg response. Healthy donor platelets (1 × 10e6) were treated with PF4 (3.75 μg/mL) for 20 min followed by 1-hour incubation with patients' sera. Platelet activation with and without addition of IVIg (levels equivalent to those reached in a patient after treatment with 2 gm/Kg) was evaluated in the PF4-dependent P-selectin expression assay (PEA). A significantly decreased platelet activation was demonstrated after the addition of IVIg to both patient samples, which correlated well with the rapid clinical response that each patient experienced. Thus, our study supports the use of IVIg as an adjunct therapy for persisting HIT.

Autotransfusion: 15 Years Experience at Rizzoli Orthopaedic Institute

The program of blood saving, result of 15 years of experience, includes predeposit (1977) hemodilution (1979) intra (1984) and postoperative (1985) salvage, careful intra and postoperative bleeding control, use of homologous transfusion only in case of intolerated anaemia even for 7-8g/dl Hb values. The use of autologous compared to homologous transfusion passed from 19% in 1984 to 62% in 1992. In 1992 in the surgical division of the 1st Anaesthesia and Intensive Care unit, 414 patients underwent prosthetic hip and knee surgery, 8% of these patients were homologously transfused.

Autotransfusion with Predeposit-Haemodilution and Perioperative Blood Salvage: 20 Years of Experience

Background

Through a prospective study, we evaluated the efficacy of an integrated autotransfusion regimen comprised of predeposit-hemodiluition and intra and post-operative blood salvage in major orthopaedic surgery.

Methods

We examined the records of 2303 consecutive patients (1524 females and 779 males, mean age 62.7, standard deviation 11 years (range 16–90 yrs), pre-operative haemoglobin (Hb) concentration 13.5 (SD 1.4) (range 6.7–19.3) g/dl undergong total hip arthroplasty (THA 1582 patients), THA after the removal of internal fixation devices (RFD+THA, 25 patients), total knee arthroplasty (TKA, 347 patients), revision surgery of the hip (HR, cup+stem revision, 248 patients; cup revision 64 patients; stem revision 23 patients) and total knee revision (TKR 14 patients). We estimated that the number of predonations (MSBOS - maximum surgery blood order schedule) was 2 units for THA, TKA and TKR, and 3 units for partial or total hip revision and for total hip arthroplasty with fixation removal.

Results

It was possible to obtain the MSBOS in 2070 patients (89.8%). Homologous red blood cell (HRBC) transfusion were carried out in 184 patients (8%). We found that the need to use HRBC was significantly associated with failure to meet the number of MSBOS, female sex, lower pre-operative Hb concentration, use of calcium heparin for antithrombosis prophylaxis, more extensive surgery, a higher ASA rating and co-existing diseases such as coronary artery disease.

Conclusions

Cooperation among anaesthesis, transfusionists and surgeons in the application of an integrated autotransfusion regimen enabled us to treat 92% of our patients with only autotransfusion.

NA62 and NA48/2 results on search for Heavy Neutral Leptons

In this paper we present new results on upper limits for the search of Heavy Neutral Leptons (HNL) with data collected by NA48/2 (2003-2004), NA62-RK (2007) and NA62 (2015) CERN experiments. The data collected with different trigger configuration allow to search for both long and short living heavy neutrinos in the mass range below the kaon mass. In addition the status of the search for K+ → π+vv with the NA62 detector will be briefly presented.

New upper limit on strange quark matter abundance in cosmic rays with the PAMELA space experiment

In this work we present results of a direct search for strange quark matter (SQM) in cosmic rays with the PAMELA space spectrometer. If this state of matter exists it may be present in cosmic rays as particles, called strangelets, having a high density and an anomalously high mass-to-charge (A/Z) ratio. A direct search in space is complementary to those from ground-based spectrometers. Furthermore, it has the advantage of being potentially capable of directly identifying these particles, without any assumption on their interaction model with Earth's atmosphere and the long-term stability in terrestrial and lunar rocks. In the rigidity range from 1.0 to ∼1.0×10^{3}  GV, no such particles were found in the data collected by PAMELA between 2006 and 2009. An upper limit on the strangelet flux in cosmic rays was therefore set for particles with charge 1≤Z≤8 and mass 4≤A≤1.2×10^{5}. This limit as a function of mass and as a function of magnetic rigidity allows us to constrain models of SQM production and propagation in the Galaxy.

Cosmic-ray positron energy spectrum measured by PAMELA

Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24,500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.

Cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV

Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray e⁻ have been identified above 50 GeV. The electron spectrum can be described with a single power-law energy dependence with spectral index -3.18 ± 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction.

PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy

The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio which extends previously published measurements down to 60 MeV and up to 180 GeV in kinetic energy. During 850 days of data acquisition approximately 1500 antiprotons were observed. The measurements are consistent with purely secondary production of antiprotons in the Galaxy. More precise secondary production models are required for a complete interpretation of the results.

One-day surgery for acquired forefoot deformity: sciatic nerve blockade with mepivacaine vs mepivacaine+ropivacaine: a prospective, randomized study

AIM

The aim of the study was to determine the doses of ropivacaine combined with mepivacaine for sciatic nerve blockade to enable the extension of analgesia without prolonged motor blockade, for the management of very painful operations in one-day surgery.

METHODS

After obtaining approval by the ethics committee and written informed consent, we recruited 30 ASA I-III patients undergoing corrective orthopedic surgery of the forefoot in one-day surgery with sciatic nerve blockade. The patients were randomly divided into 3 groups: one control group, treated by 1.5% mepivacaine (300 mg), and two groups differentiated by the dose of 0.5% ropivacaine (25 and 40 mg) used in combination with 1.5% mepivacaine (225 mg). The offset data of the blockade were obtained by a self-assessment form filled in by the patients, and a direct check on discharge by a blinded observer.

RESULTS

There was no significant difference in the duration of the blockade among the 3 groups; the extension of analgesia was significant (P<0.003) in the group treated by mepivacaine+ropivacaine 40 mg (mean 477+/-255 min).

CONCLUSION

Adequate doses of ropivacaine added to mepivacaine for peripheral blockade produce and increase the duration of analgesia without influencing the criteria for discharge after Day Surgery.

Pacemaker-induced mitral regurgitation: prominent role of abnormal ventricular activation sequence versus altered atrioventricular synchrony

BACKGROUND

Functional mitral regurgitation is a hemodynamic adverse consequence of right ventricular apical pacing that profoundly modifies the contraction and relaxation of the left ventricle by inverting and delaying its activation sequence. The aim of this study was to analyze by Doppler echocardiography in the acute setting the true incidence and the mechanism responsible for the right ventricular apical pacing-induced mitral regurgitation.

METHODS

We studied 27 consecutive patients submitted to pacemaker implantation (VVI n = 9; DDD n = 18) because of bradyarrhythmias. The exclusion criteria were structural cardiac disease and permanent atrioventricular block. Patients underwent Doppler echocardiographic examination during both spontaneous rhythm (pacemaker off) as well as during programmed pacing at a rate of 70 b/min. In case of a double chamber pacemaker, a non-optimized atrioventricular delay of 150 ms was chosen.

RESULTS

Two groups were identified: 11 patients with (Group 1, mean age 71 +/- 7 years) and 16 patients without (Group 2, mean age 71 +/- 4 years) new-onset pacing-induced mitral regurgitation. The incidence of mitral regurgitation was found to be higher during DDD (33%) than during VVI (24%) pacing mode. The relationship between gender and the occurrence of pacing-induced mitral regurgitation was striking: 10/13 women (77%) presented with mitral regurgitation during acute right ventricular apical pacing while this complication occurred in only 1/14 men (7%). Moreover, analysis of variance (ANOVA) and post-hoc pairwise multiple comparison showed an increased size of the mitral apparatus, as defined by the enlargement of the annulus (long axis 28 +/- 3 vs 23 +/- 2 mm; short axis 25 +/- 3 vs 20 +/- 3 mm, p = 0.05) and the lengthening of the anterior mitral leaflet (23 +/- 4 vs 18 +/- 2 mm, p = 0.05) and chordae tendineae (16 +/- 3 vs 13 +/- 2 mm, p = 0.05). This was probably related to the high female prevalence (91%) in Group 1 as compared to the control group (50 healthy subjects; 17 men, 33 women; mean age 71 +/- 8 years). No significant differences were observed between Group 2 and controls.

CONCLUSIONS

Our study confirmed that functional mitral regurgitation is a frequent consequence of right ventricular apical pacing. Despite the maintenance of normal atrioventricular synchrony, we found that the pathway for ventricular depolarization was the critical determinant of normal mitral valve function. Such data show the importance of the preservation of a normal ventricular activation sequence during permanent cardiac pacing where it is technically feasible. Female patients seemed to be exposed to a higher risk of pacing-induced mitral regurgitation due to an anatomic predisposing condition of the mitral apparatus and to the left ventricular dyssynchronous contraction secondary to right ventricular apical pacing.

Repolarization changes in a double-blind crossover study of dofetilide versus sotalol in the treatment of ventricular tachycardia

The aim of this study was to determine whether a therapeutic response to Class III antiarrhythmic drugs is related to predictable changes in repolarization on the electrocardiogram (ECG). A group of 57 patients with ischemic heart disease and inducible ventricular tachycardia (VT) at electrophysiological study (EPS) were selected from a population enrolled in a randomized double-blind crossover study of dofetilide (500 micrograms bid) versus sotalol (160 mg bid). ECGs were analyzed blindly, and RR, QT (maximum value/12 leads), QTc (Bazett's formula), QT dispersion (QTmax-QTmin over 12 leads) and QTc dispersion, were calculated at baseline and on the third day of treatment (4 hours after dosing), when patients underwent EPS to test the effects of study drugs on VT inducibility.

RESULTS

At EPS 21 patients were responders to dofetilide and 22 to sotalol. On day 3, a significant increase in QT and QTc and decrease in QT and QTc dispersion, compared to baseline, was measured in responders and nonresponders, with both dofetilide and sotalol. No significant difference in QTc or QT dispersion between responders and nonresponders was observed in either treatment group. In conclusion, treatment with dofetilide and sotalol was associated with an increase in QT and QTc, and a decrease in QT and QTc dispersion. In contrast with previous reports, a differential effect on QT or QTc dispersion was not observed in drug responders versus nonresponders.

Isolation of HTLV-1 from an aggressive form of ATL in a Romanian patient not at risk of infection and with seronegative family members

We present the clinical, virological and haematochemical data of a 22 year old patient from Romania with Adult T Cell Leukaemia (ATL). Viral isolation in peripheral mononuclear blood cells (PMBC), detection of DNA sequences of HTLV-1 by Polymerase Chain Reaction (PCR) and of antibodies by Elisa and Western blot were performed. The patient does not belong to any risk group and additionally all members of her family are seronegative for HTLV-1, the aetiological agent of ATL. The role of viral infection remains open.

[Carotid thromboendarterectomy: personal experience and review of the literature]

Carotid endoarterectomy (CEA) is known to prevent cerebrovascular accidents. Between February 1987 and December 1993 we performed 97 CEA on 82 patients (62 male and 20 female, median age 66 +/- 7.6 years) 95.1% reported previous hemispheric neurological accidents; 4.9% were asymptomatic. Operative indications for asymptomatic patients were high degree stenosis (> 70%) of the internal carotid artery and ulcerated plaques with a moderate degree (50%) of stenosis. Major events (transient ischemic attack and stroke) were recorded in 73.2% cases. Preoperative investigations consisted of Duplex scan, arteriography, and cerebral CT scan or NMR. Operative mortality was 2.06% (2 cases) and perioperative stroke was 5.1% (5 cases). The sensibility, sensitivity and accuracy of Duplex scan to detect ulcerated plaques was 88.7%, 85.2% and 87.5% respectively. At a median follow-up of 33 months (range 6-81 months) 74 (92.5%) patients are free of strokes whereas 1 patient died for stroke. In our series the annual incidence of stroke was 0.5%. Our results suggest that Duplex scan is a reliable exam to investigate the carotid axis and CEA is a safe operation that prevents future cerebrovascular accidents.

Methods of blood saving in revision surgery of the hip

The blood saving protocol, which is the product of 15 years of experience, has gradually been improved, until the current form has been achieved, which includes predeposit, acute intentional isovolemic hemodilution, controlled hypotension, intraoperative blood recovery, postoperative monitoring and blood recovery, external compressive elastic dressing. The acceptance of values for hemoglobin which may even be < 8 g/dl during the late postoperative period, as long as this is well-tolerated by patients, has allowed us to drastically reduce the use of homologous transfusions. Over the last 2 years, out of 59 autotransfused patients submitted to revision surgery of the hip, only 9 (equal to 15%) required homologous transfusion. An analysis of the data shows that the use of homologous blood is associated with the presence of ischemic cardiopathy (p < 0.001) and with a predeposit which is less than 4 units of blood (packed red blood cell+fresh frozen plasma) (p = 0.05).

Autotransfusion: 15 years experience at Rizzoli Orthopaedic Institute

The program of blood saving, result of 15 years of experience, includes predeposit (1977) hemodilution (1979) intra (1984) and postoperative (1985) salvage, careful intra and postoperative bleeding control, use of homologous transfusion only in case of intolerated anaemia even for 7-8g/dl Hb values. The use of autologous compared to homologous transfusion passed from 19% in 1984 to 62% in 1992. In 1992 in the surgical division of the 1st Anaesthesia and Intensive Care unit, 414 patients underwent prosthetic hip and knee surgery, 8% of these patients were homologously transfused.