Time-resolved study of holeboring in realistic experimental conditions.

The evolution of dense plasmas prior to the arrival of the peak of the laser irradiation is critical to understanding relativistic laser plasma interactions. The spectral properties of a reflected laser pulse after the interaction with a plasma can be used to gain insights about the interaction itself, whereas the effect of holeboring has a predominant role. Here we developed an analytical model, describing the non-relativistic temporal evolution of the holeboring velocity in the presence of an arbitrary overdense plasma density and laser intensity profile. We verify this using two-dimensional particle-in-cell simulations, showing a major influence on the holeboring dynamic depending on the density profile. The influence on the reflected laser pulse has been verified during an experiment at the PHELIX laser. We show that this enables the possibility to determine the sub-micrometer scale length of the preplasma by measuring the maximum holeboring velocity and acceleration during the laser-plasma interaction.

Whole blood rotation thromboelastometry (ROTEM(®)) in nine severe factor V deficient patients and evaluation of the role of intraplatelets factor V.

Severe factor V (FV) deficiency (parahaemophilia) is a rare congenital hemorrhagic disorder characterized by very low or undetectable plasma FV levels and bleeding phenotype ranging from mild to severe. We evaluated whole blood (WB) rotation thromboelastometry (ROTEM) in parahaemophilia patients and the contribution of intraplatelets FV, if any, to clot formation. Standard ROTEM(®) assays were performed in WB from nine parahaemophilia patients and 50 healthy controls. In addition, platelets poor plasma from one parahaemophilia patient (PPP-Pt) or normal subjects (PPP-N) was reconstituted with washed platelets obtained either from one patient with parahaemophilia (Plts-Pt) or normal subjects (Plts-N) and ROTEM assays were performed in platelets rich plasma (PRP) samples. There was a prolongation of the WB clotting time (CT) in all assays in patients as compared with controls. However, maximum clot firmness (MCF) was similar in patients and controls. ROTEM in PPP-Pt showed both a prolongation of CT and a reduction of MCF as compared with PPP-N. The addition of either Plts-Pt or Plts-N to PPP-Pt resulted in similar increase in MCF and a decrease of CT which was more evident for PPP-Pt + Plts-N than PPP-Pt + Plts-Pt. In contrast, the addition of Plts-Pt or Plts-N to PPP-N had superimposable effects on both CT and MCF. In parahaemophilia patients, WB ROTEM(®) presents mainly with prolongation of CT and no relevant effect on MCF. Residual intraplatelets FV in parahaemophilia contributes significantly to thrombin generation as shown in artificially reconstituted PRP models.

Dielectron production in 12C+12C collisions at 2A GeV with the HADES spectrometer.

The invariant-mass spectrum of e+e- pairs produced in 12C+12C collisions at an incident energy of 2 GeV per nucleon has been measured for the first time. The measured pair production probabilities span over 5 orders of magnitude from the pi(0)-Dalitz to the rho/omega invariant-mass region. Dalitz decays of pi(0) and eta account for all the yield up to 0.15 GeV/c(2), but for only about 50% above this mass. A comparison with model calculations shows that the excess pair yield is likely due to baryon-resonance and vector-meson decays. Transport calculations based on vacuum spectral functions fail, however, to describe the entire mass region.

Diagnosis and surgical treatment of the carotid body tumors.

Resection of carotid body tumors can be difficult to perform because of its site, vascularity, arterial adherence and local cranial nerve involvement. Advances in vascular surgical technique have reduced the risks of perioperative complications such as carotid injury, stroke and death. From January 1980 to May 1994 20 patients (22 carotid body tumors) were examined. All patients except one were evaluated with a preoperative angiography. No preoperative embolization was performed. Thirteen patients underwent ultrasonography, nine a CT scan of the neck, 5 magnetic resonance scanning and two magnetic resonance angiography. One old patient refused operation. The authors report their experience on 21 carotid body tumor resections (14 Shamblin group I and 7 group II paragangliomas). Surgical technique is based on subadventitial resection (18 excisions) and 3 resections were performed from the medial surface of the carotid bifurcation which had been partially absorbed into the mass. In the last 15 operations intraoperative Somatosensorial Evoked Potential (SEP) monitoring has been used. Only two patient required arterial repair because intimal dissection and another patient needed vagus nerve section. The ligation of external carotid artery and internal carotid resection with graft replacement were never necessary in these patients. No early or late deaths occurred and no recurrences were detected at follow-up.

The role of endovascular surgery in carotid restenosis.

PURPOSE: To report the immediate and long-term outcome of intraoperative balloon angioplasty for the treatment of recurrent disease in the internal carotid arteries (ICAs). METHODS: Three patients (2 males, 1 female; ages 53 to 70 years) presented with > 80% restenotic lesions (bilateral in one patient) at the distal aspect of a previous carotid endarterectomy. Two patients exhibited hemianopia, while the third was asymptomatic but had a contralateral ICA occlusion. All four lesions appeared smooth and fibrous on ultrasonography and were located high in the ICA. The location and morphology of the lesions made balloon angioplasty a more potentially successful treatment option. RESULTS: Through open access to the common carotid artery, the lesions were approached and dilated under fluoroscopic guidance with monitoring of evoked potentials. The lesions were successfully dilated as determined by control arteriography, and no complications were encountered. Over a follow-up period extending to 18 months in one patient and 24 months in the other two, ultrasound imaging and arteriography have shown no restenosis at any treatment site. CONCLUSIONS: Although caution is prudent when dealing with lesions in the cervical arteries, balloon angioplasty may have a role in treating surgically inaccessible restenotic carotid lesions that demonstrate a low potential for embolic complications. More experience with this technique will be required before widespread application of balloon angioplasty in the cervical vessels can occur.

Prevention of early graft infection with rifampicin-bonded Gelseal grafts: a multicentre experimental study.

The possibility of increasing the resistance of a synthetic vascular graft to intraoperative or immediate postoperative bacterial contamination justifies the interest in methods such as antibiotic bonding or antibiotic soaking. On the basis of this experience and with the aim of testing the efficacy of such a graft, a multicentre experimental study on sheep to compare the susceptibility to infection of Dacron Gelseal grafts (control) versus rifampicin-bonded Dacron Gelseal grafts (treated) following the intravenous infusion of 10(7)-10(8) cells Staphylococcus aureus was conducted. The grafts were implanted in both common carotid arteries of sheep. In a group of 11 animals (group A), a treated and a control graft were implanted in the same animal. In a group of four sheep (group B), only treated or control grafts were implanted in each animal. In group A, 36% of (four of 11) the treated grafts became infected versus 54% (six of 11) of the control prostheses. In group B, none of the treated grafts was infected by the inoculated pathogen, which, by contrast, infected 75% (three of four) of the controls. These observations confirm the recent interest aroused by the possibility of pretreating gelatin-coated Dacron grafts with rifampicin in the prevention of early graft infection.

[The choice of approach in the surgical therapy of the superior thoracic outlet syndrome]. / La scelta della via di approccio nella terapia chirurgica della sindrome dello stretto toracico superiore.

The symptoms of thoracic outlet syndrome (TOS) may be improved or cured either by physiotherapy or by a surgical operation. The choice of patients to be submitted to surgery must be performed on the basis of clinical picture and of non invasive and invasive assessment. Moreover the surgeon must choose the best procedure to relieve symptoms. The Authors on the basis of their experience and of a literature review refer to the various surgical approaches used in the treatment of TOS.

Indobufen vs acetylsalicylic acid plus dipyridamole in long-term patency after femoropopliteal bypass.

To compare the effects of indobufen (INB) with those of ASA+dipyridamole (DP) on graft patency, 113 patients undergoing femoropopliteal bypass surgery were randomly and blindly assigned to treatment with INB 400 mg daily or with ASA 900 mg daily plus DP 225 mg daily. Treatment started 2 days before surgery and lasted for 12 months. All patients underwent two angiographic examinations: the first early after surgery (mean 6 days) and the second at the end of the study (mean 368 days). The 1 year cumulative patency rate for INB was 60% higher but not statistically different from the ASA-DP group (53.2%). The relative risk (INB/ASA+DP) calculated by the Mantel-Haenszel test was 0.86 (confidence limits 0.54-1.35). Only the site of operation (above-knee or below-knee) has a significant prognostic value on the fate of the graft.

Indobufen versus placebo in the prevention of restenosis after carotid endarterectomy: a double-blind pilot study.

A randomized clinical trial was undertaken to assess the efficacy of indobufen in inhibiting platelet adhesiveness in carotid thromboendarterectomy. The patients were treated under double-blind conditions with indobufen and with placebo, and were then assessed by means of scintigraphy with labelled platelets, ultrasonic tomography and angiography for a minimum follow-up period of 6 months. Haematological and clinical assessments were also performed. The results of the study suggest that platelet accumulation in carotid endarterectomy may be an early sign of restenosis; anti-aggregant treatment with indobufen carried out at an early stage prior to surgery inhibited platelet accumulation. The final result showed that anti-aggregant treatment had a positive influence on the short- and medium-term outcome of carotid endarterectomy.

Selective shunting based on somatosensory evoked potential monitoring during carotid endarterectomy.

Somatosensory Evoked Potentials (SEPs), to median nerve stimulation, were continuously monitored in 58 patients undergoing carotid endarterectomy A first group of patients was shunted routinely; in a second group the shunt was selectively applied when inadequacy of collateral circulation was suspected based on stump pressure values and SEP changes. Both amplitude and latency modifications of SEPs occurred during surgery; however no post-operative neurological deficit was seen unless there was a complete flattening of cortical waves, even a transitory one. Inadequate collateral circulation and embolic ischemia affected SEPs differently. While the latter produced a disappearance of all cortical waves, the former led first to a progressive flattening of later cortical waves and then of N20 as well. For values of stump pressure ranging between 20 and 50 mmHg SEPs were unchanged in some patients and altered in others. These findings may explain the controversies existing about the usefulness of stump pressure for predicting tolerance to carotid clamping.

[Preparation of some pyrido (2,3-e)-1,4-diazepines]. / Preparazione di alcune pirido (2,3-e)-1,4-diazepine

By treating pyrido (2,3-e)-1,4-diazepinones with alkyl halides, N4-alkylpyrido (2,3-e)-1,4-diazepines were obtained. In addition a number of N1-alkylpyrido (2,3-e)-1,4-diazepines were prepared from alkyltetrahydronaphthyridinones by the Schmidt reaction. Preliminary pharmacological screening of some of these compounds showed no appreciable activity.

1,8-naphthyridine derivatives: synthesis and pharmacological evaluation of beta-receptor blocking activity.

The synthesis of a number of 1-alkyl-7-(2-hydroxy-3-alkylaminopropoxy)-1,8-naphthyridin-2-ones is described. The compounds studied were prepared by reaction of 1-alkyl-7-hydroxy-1,8-naphthyridin-2-ones with epichlorohydrin. The substituted epoxy intermediates obtained were allowed to react with amines and gave the desired products. All the compunds prepared were devoid of beta-blocking activity.