Hard Photon Pair Production at LEP

The production of photon pairs in $e^+e^-\rightarrow f \bar f \gamma\gamma$ processes is studied using exact helicity amplitudes at tree level. Total cross sections, including initial state radiation effects, are given. They are presented in the case of quarks as a function of $y_{\rm cut}$ in the JADE algorithm. In the case of leptons we use cuts similar to the ones employed in a recent L3 analysis. Masses of the final state fermions are taken into account when appropriate. The cross section $e^+e^-\rightarrow \tau^+ \tau^- \gamma\gamma$ is about 10\% larger when the $\tau$ mass is neglected. We obtain, with a different method, results which are in good agreement with L3 Montecarlo simulation.Comment: 7 Pages (4 Figs available from the authors in Postscript or via Fax ), LaTex, DFTT 4/9

Fat Tissue’s Graft in Osteoarthritis Treatment: Indications, Preparations, and Results

Osteoarthritis (OA) represents one of the most common causes of joint pain and disability with related changes in bone morphology. In last years, this pathology is steadily increasing due to the continuous increase in the average life expectancy and the rate of active population. In recent years, there have been many conservative treatments for symptomatic gonarthrosis in order to reduce pain and delay or avoid the implantation of a knee prosthesis. The most studied and used was infiltrating treatment. Our group has been paying attention to regenerative medicine for many years, focusing on the characteristics of adipose tissue and the presence of multipotent mesenchymal cells, particularly in the vascular stromal area. Mesenchymal stem cells (MSCs) of adipose tissue can commit toward the chondrogenic, osteogenic, adipogenic, myogenic, and neurogenic lineages. Our group has continued the studies in this field by submitting this to treatment patients with grade II–III arthrosis according to the scale of Kellgren-Lawrence or patients with IV degree of such scale inoperable for internal reasons. To date, with a 4-year follow-up, our results are satisfactory in terms of pain reduction, improvement in joint function, and recovery of daily and sports activities

Arthroscopic guided biopsy and radiofrequency thermoablation of a benign neoplasm of the tibial spines area: a treatment option

<p>Abstract</p> <p>Background</p> <p>Lesions located in the area of the tibial spines are rare. In most cases, treatment follows histological diagnosis, but when imaging and clinical data are considered to be "very" characteristic for benign lesions, such as chondroblastoma or osteoid osteoma, treatment may be performed without biopsy. Traditional curettage requires opening the joint, which presents a high risk of contamination of the joint itself and surrounding structures, such as the popliteal area, with possible contamination of the neurovascular bundle when performing curettage with the posterior approach. In this case, the re-excision of a local recurrence would be extremely difficult.</p> <p>Results</p> <p>We describe a technique using arthroscopic guidance for radiofrequency thermoablation of a benign lesion in the tibial spines area. We report on an illustrative case. The patient so treated, reported immediate relief from the pain, and after two weeks, was free of pain. The biopsy performed before the treatment confirmed the radiological diagnosis of chondroblastoma. At one year of follow-up, the patient is without pain, with a 0-130°range of motion, has no activity limitations and is apparently free of disease.</p> <p>Conclusion</p> <p>This technique allows a radiofrequency thermoablation of a lesion in the tibial spines area and in the posterior tibial surface to be performed without opening the joint, monitoring the tibial plateau surface, probably decreasing the risk of cartilage damage. Unfortunately, in the case presented, the high pressure from the arthroscopy's pump broke the tibial plateau surface creating a communication to the tibial tunnel used for thermoablation.</p

Heavy Quarks and Leptons at e+e−e^+e^- Colliders

The production of massive quarks and leptons in $e^+e^-$ collisions is studied using exact helicity amplitudes. Total cross sections as a function of $y_{\rm cut}$, in both the JADE and the $k_T$ algorithms, are presented and compared with massless results. Some invariant mass distributions are examined in relation to Higgs detection. Compact expressions for the helicity amplitudes are given.Comment: 32 Pages (20 Figs available from the authors in Postscript or via Fax ), Plain Tex, DFTT 53/9

Prepuberal stimulation of 5-HT7-R by LP-211 in a rat model of hyper-activity and attention-deficit: permanent effects on attention, brain amino acids and synaptic markers in the fronto-striatal interface

The cross-talk at the prefronto-striatal interface involves excitatory amino acids, different receptors, transducers and modulators. We investigated long-term effects of a prepuberal, subchronic 5-HT7-R agonist (LP-211) on adult behaviour, amino acids and synaptic markers in a model for Attention-Deficit/Hyperactivity Disorder (ADHD). Naples High Excitability rats (NHE) and their Random Bred controls (NRB) were daily treated with LP-211 in the 5th and 6th postnatal week. One month after treatment, these rats were tested for indices of activity, non selective (NSA), selective spatial attention (SSA) and emotionality. The quantity of L-Glutamate (L-Glu), L-Aspartate (L-Asp) and L-Leucine (L-Leu), dopamine transporter (DAT), NMDAR1 subunit and CAMKIIα, were assessed in prefrontal cortex (PFC), dorsal (DS) and ventral striatum (VS), for their role in synaptic transmission, neural plasticity and information processing. Prepuberal LP-211 (at lower dose) reduced horizontal activity and (at higher dose) increased SSA, only for NHE but not in NRB rats. Prepuberal LP-211 increased, in NHE rats, L-Glu in the PFC and L-Asp in the VS (at 0.250 mg/kg dose), whereas (at 0.125 mg/kg dose) it decreased L-Glu and L-Asp in the DS. The L-Glu was decreased, at 0.125 mg/kg, only in the VS of NRB rats. The DAT levels were decreased with the 0.125 mg/kg dose (in the PFC), and increased with the 0.250 mg/kg dose (in the VS), significantly for NHE rats. The basal NMDAR1 level was higher in the PFC of NHE than NRB rats; LP-211 treatment (at 0.125 mg/kg dose) decreased NMDAR1 in the VS of NRB rats. This study represents a starting point about the impact of developmental 5-HT7-R activation on neuro-physiology of attentive processes, executive functions and their neural substrates

Ontogenesis of behavioral sensitization and conditioned place preference induced by psychostimulants in laboratory rodents

The present review deals mainly with the ontogenesis of two important phenomena involved in vulnerability to several neuropsychiatric disorders, namely with drug-induced sensitization (both contextual and non-contextual) and with conditioned place preference. The term 'infancy' covers the first three postnatal weeks during development in rats and mice. Conversely, the term 'adolescence' may cover the whole postnatal period ranging from weaning (PND 21) to adulthood (at least PND 60) or specifically the period around the onset of puberty (animals aged 33-44 days). Recent studies in rats demonstrated that the establishment of a context-dependent sensitization appears during the first (for repeated drug administration) or during the second (for a single drug administration) postnatal week. However, the memory of drug-context association is transient in developing pups (lasting one or two days following the drug pretreatment). The long-term retention of drug-context associations matures progressively, and is complete by the third week of postnatal life. Finally, those mechanisms responsible for an adult-like profile of context-independent pharmacological sensitization appear later during ontogenesis, being mature by the fourth week of postnatal life. Another set of experiments extended this ontogenetic characterization by comparing adolescent and adult mice. When compared to the latter, the former subjects exhibit a greater amphetamine-induced locomotor sensitization, almost no sensitization of aversive stereotyped behaviors, and a less marked place conditioning. The strength of the drug-induced place conditioning was also directly compared with the unconditioned novelty-seeking drive. In conclusion, neonatal rats are able to show a relatively short-lasting retention of sensitized drug effects (short-term sensitization), whereas the ability to exhibit relatively long-lasting sensitized effects matures progressively during infancy (long-term sensitization). On the other hand, adolescent mice show a reduced sensitization of drug-induced psychotic symptoms, together with a more marked sensitization of arousing and euphorigenic properties of the drug and a reduced incentive memory of its hedonic effects. These age-related changes do imply very different degrees of vulnerability to drug addiction and several other neuropsychiatric disorders. (C) 2003 Elsevier Science Ltd. All rights reserved

Pre-operative planning in anterior cruciate ligament reconstruction revision surgery

Primary reconstructions of the anterior cruciate ligament are common and increasing in number, a trend inevitably paralleled by an increase in the number of revision procedures. Failure of primary ACL reconstruction can appear as objective residual laxity, subjective instability, severe and persistent postoperative stiffness and/or pain, or infection. Revision surgery is a complex procedure, in which the expected clinical outcome is inferior to that which can be expected from primary reconstruction, and patients have a 5.4% risk of undergoing a second revision after five years. This type of procedure demands correct and exhaustive preoperative planning so as ensure optimal treatment of accompanying lesions and of any complications arising during surgery. It is important to know, in detail, the patient’s clinical history (when the primary surgery was performed and the technique used, the cause of the recurrence, the degree of functional recovery, etc.), to perform a thorough clinical examination (to evaluate alignment, gait cycle, skin color, the trophic condition of the muscles, joint laxity), and to have available the results of a detailed and specific imaging study and also of blood tests, in order to exclude the presence of an infection