Strong Reduction of the Effective Radiation Length in an Axially Oriented Scintillator Crystal.

We measured a considerable increase of the emitted radiation by 120 GeV/c electrons in an axially oriented lead tungstate scintillator crystal, if compared to the case in which the sample was not aligned with the beam direction. This enhancement resulted from the interaction of particles with the strong crystalline electromagnetic field. The data collected at the external lines of the CERN Super Proton Synchrotron were critically compared to Monte Carlo simulations based on the Baier-Katkov quasiclassical method, highlighting a reduction of the scintillator radiation length by a factor of 5 in the case of beam alignment with the [001] crystal axes. The observed effect opens the way to the realization of compact electromagnetic calorimeters or detectors based on oriented scintillator crystals in which the amount of material can be strongly reduced with respect to the state of the art. These devices could have relevant applications in fixed-target experiments, as well as in satellite-borne γ telescopes.

Bent crystals for efficient beam steering of multi TeV-particle beams.

Charged particle beams can be manipulated by exploiting the channeling phenomenon in bent crystals. Two plate-like crystals, bent by mechanical holders, were manufactured and characterised for such purpose at the Sensor and Semiconductor Laboratory in Ferrara, Italy. An anticlastic curvature was obtained for these crystals, achieving a steering angle of the order of 1 mrad, which is about 20 times larger than the values currently achieved for the bent crystals used in the LHC for collimation experiments. Finally, a Geant4 simulation was performed to study the channeling efficiency for beam deflection with 400 GeV/c and 7 TeV/c proton beams. Such crystals represent technological progress in the development of bent crystals for highly energetic charged particle beams. Indeed, they are designed to impart an angular kick to a 7 TeV/c proton beam with unprecedented high efficiency. Therefore, this study demonstrates the possibility of realizing bent crystals suitable for beam extraction in high-energy hadron accelerators, such as LHC or at the future FCC. A further series of studies should be conducted to evaluate the channeling efficiency and the deflection angle of the realized crystals via a charged proton beam.

Analysis of calcium-dependent protein kinase-C isoenzymes in intrinsically resistant cloned lines of LoVo cells: reversal of resistance by kinase inhibitor 1-(5-isoquinolinylsulfonyl) 2-methylpiperazine.

In order to investigate the involvement of Protein Kinase C (PKC) in the signal transduction mechanisms related to intrinsic chemoresistance, two cellular clones were isolated from LoVo/WT colon adenocarcinoma cell line and their cytogenetic pattern was studied: LoVo C1.7 was intrinsically resistant to Doxorubicin while LoVo C1.5 showed the same resistance index as the mixed parental cell population. Two PKC isoforms, immunologically identified as beta and alpha PKC, were isolated from the cytosolic fraction of all cell types and one single peak of alpha PKC was obtained from the particulate fraction. Resistant LoVo C1.7 cells showed a significant increase of PKC activity; preincubation with H-7 induced PKC inhibition and reversal of drug resistance. These data suggest that in our cell system the identified calcium-dependent PKC subtypes can play a role in the mechanisms of intrinsic resistance.

Comparison of spontaneous ascites filtration and reinfusion with total paracentesis with intravenous albumin infusion in cirrhotic patients with tense ascites.

OBJECTIVE: To compare the effectiveness and safety of spontaneous ascites filtration and reinfusion and total paracentesis plus intravenous albumin infusion in cirrhotic patients with tense ascites. DESIGN: Randomised trial of the two treatments. SETTING: Teaching hospital and district general hospital in Milan. PATIENTS: 45 consecutive cirrhotic patients with recurrent tense ascites and urinary sodium excretion rate less than 20 mmol/day. 35 fulfilled admission criteria and completed the study. 17 received spontaneous ascites filtration and 18 paracentesis plus albumin infusion. MAIN OUTCOME MEASURES: Body weight; urinary volume; serum and urinary electrolyte, serum fibrinogen, and plasma aldosterone concentrations; and plasma renin activity before the procedure and 24 hours and eight days afterwards. RESULTS: Both procedures were effective in all patients. Weight decreased in both groups and showed no substantial increase after eight days. In patients receiving ascites filtration, values decreased significantly (p less than 0.01) after 24 hours for platelet count (mean relative change 0.92; 99% confidence interval 0.86 to 0.98) and serum fibrinogen concentration (0.92; 0.88 to 0.98) but returned to pretreatment values after eight days; no laboratory and clinical signs of disseminated intravascular coagulation were noted. Three patients in this group had fever, which receded spontaneously. One patient in each group had dilutional hyponatraemia. CONCLUSIONS: Spontaneous ascites filtration and reinfusion is an effective treatment for tense ascites. Reinfusion of the patient's concentrated proteins provides savings without compromising safety.

An unusual case of anuria: spontaneous perirenal hematoma in a solitary kidney.

A 71-year-old woman with a solitary kidney who developed acute renal failure with anuria secondary to a spontaneous perirenal hematoma is described. Serum creatinine peaked at 335.9 micromol/L and BUN at 26.4 mmol/L, but neither surgery nor dialysis treatment was performed because renal function gradually improved. In this syndrome, first described by Wunderlich in 1856, anuria was not previously reported. Conservative management must always be considered rather than emergency surgery, which usually results in nephrectomy.

Flow cytometric analysis of leukocytes eluted from haemodialysers.

The cellular immune system is impaired in uraemic and haemodialysed patients. We describe a method of studying leukocytes eluted from dialysers at the end of the dialysis session, and we have studied five haemodialysers: cuprophane (CU), cellulose acetate (CA), polymethylemethacrylate (PMMA), polyacrylonitrile (PN), and polysulphone (PS). The analysis was performed by flow cytofluorimetry using monoclonal antibodies. The absolute number of eluted leukocytes was rather elevated, ranging from 88 (CU) to 9 (PS) millions of cells. When compared to peripheral blood values, the percentage analysis revealed an increase of PMN and monocytes and a decrease of lymphocytes. A relative increase of B lymphocytes was observed in all filters studied. A trapping of T lymphocytes (PAN) and a minor increase of NK cells (PMMA, PS, CA) were also observed. The elution of leukocytes from dialysers may be helpful in evaluating the biocompatibility of membranes for haemodialysis.

Increase in plasma extracellular fluid volume ratio caused by bilateral nephrectomy in patients on maintenance hemodialysis.

Changes, observed in rats after bilateral nephrectomy, in blood pressure and in the relation betwen plasma volume-extracellular fluid volume or plasma volume-interstitial fluid volume, are consistent with the postulation that the kidney secretes a substance that regulates, to some degree, the compliance of the interstitial space. In order to evaluate the possibility that this also occurs in humans, we have carried out a retrospective analysis of measurements of extracellular fluid volume, plasma volume, and blood volume made prior to and after bilateral nephrectomy in a group of 9 patients. It was observed that significant increases had occurred in both the plasma-extracellular fluid volume ratio (0.22 before, 0.26 after) and in the blood-extracellular fluid volume ratio (0.27 before, 0.32 after). These data are consistent with a reduction in compliance of the interstitial compartment caused by bilateral nephrectomy in man, even though other explanations cannot be excluded.

Fragile-X mental retardation in a large five-generation family. A clinical and cytogenetic study.

A number of problems concerning both clinical and genetic or cytogenetic aspects of the fragile-X syndrome remain unsolved. In the present work, a large 5-generation fragile-X family has been clinically and cytogenetically investigated. The results of our study indicated that an unusually high proportion of affected males was present in the family examined; all fragile-X-positive males were profoundly retarded and showed the phenotype typically described for this syndrome; moreover, we observed a variability of penetrance within the pedigree and all fragile-X-positive females in the 4th and 5th generation had some degree of mental impairment. A multistep mutation model has been proposed in order to explain some of these findings.

Cytological analysis and sorting of a human supernumerary minichromosome.

In a newborn female, an abnormal karyotype, 46,XX/47,XX,+mar/47,XX,+9, was found associated with several malformations. The marker chromosome was present in 70% of peripheral blood lymphocytes, and its size appeared to be less than half of the smallest chromosomes. Several differential staining methods provided no indication as to its origin.Chromosomes isolated from EBV-immortalized lymphocytes of the patient were fractionated on a FACS-440. The marker was resolved as a sharp peak in the region close to the chromosomal debris: its DNA content seemed to be close to 40% of chromosomes 21 and 22.About 580000 minichromosomes were sorted. In order to optimize cloning conditions, a pilot cloning experiment was performed on a pool of sorted chromosomes 9, 10, 11 and 12.

A simple method for ascites concentration and reinfusion.

A rapid and simple method for ascites concentration and reinfusion was utilized to treat 103 episodes of tense ascites in 57 patients (38 men and 19 women, mean age 63 +/- 11 years). After a bedside total paracentesis, 6.06 +/- 2.87 liters of ascites were separately ultrafiltrated using a mechanical device during a mean interval of 134 +/- 88 min, and 430 +/- 368 ml of concentrate containing 39 +/- 42 g of albumin were restituted at bedside either intravenously (44 cases) or intraperitoneally (59 cases). Ultrafiltration was successfully and easily completed in all cases. Ascites concentration and reinfusion either intravenously or intraperitoneally did not adversely modify hemodynamic or renal parameters except for a transient decrease in mean arterial pressure (P < 0.05). Transitory hyponatremia and renal failure occurred in two patients. A transient decrease in platelet count and serum fibrinogen levels (P < 0.05) and pyrexia (12%) were observed only in patients reinfused intravenously. In conclusion, this new method for ascites concentration and reinfusion was effective, safe, and, with respect to traditional methods, simpler, faster and more comfortable. Therefore it is proposed for the routine management of tense ascites.

A comparison of short and long haemodialysis.

Two groups of patients treated by short (Milan) and long (Newcastle) haemodialysis were compared for incidence of symptoms and biochemical control. Short dialysis corrected urea and creatinine as well but control of potassium and phosphate were similar. The only apparent penalties to be paid by short dialysis patients were a higher incidence of itching, tingling or numbness, impairment of vibratory sense and difficulty in controlling blood pressure. The short dialysis group had higher haemoglobin and less dyspnoea, muscle weakness and dizziness after dialysis.