Fast electron transport and induced heating in solid targets from rear-side interferometry imaging.

Fast adiabatic plasma heating of a thin solid target irradiated by a high intensity laser has been observed by an optical fast interferometry diagnostic. It is driven by the hot electron current induced by the laser plasma interaction at the front side of the target. Radial and longitudinal temperature profiles are calculated to reproduce the observed rear-side plasma expansion. The main parameters of the suprathermal electrons (number, temperature, and divergence) have been deduced from these observations.

Direct evidence of strongly inhomogeneous energy deposition in target heating with laser-produced ion beams.

We report on strong nonuniformities in target heating with intense, laser-produced proton beams. The observed inhomogeneity in energy deposition can strongly perturb equation of state (EOS) measurements with laser-accelerated ions which are planned in several laboratories. Interferometric measurements of the target expansion show different expansion velocities on the front and rear surfaces, indicating a strong difference in local temperature. The nonuniformity indicates at an additional heating mechanism, which seems to originate from electrons in the keV range.

Generation of quasimonoenergetic electron bunches with 80-fs laser pulses.

Highly collimated, quasimonoenergetic multi-MeV electron bunches were generated by the interaction of tightly focused, 80-fs laser pulses in a high-pressure gas jet. These monoenergetic bunches are characteristic of wakefield acceleration in the highly nonlinear wave breaking regime, which was previously thought to be accessible only by much shorter laser pulses in thinner plasmas. In our experiment, the initially long laser pulse was modified in underdense plasma to match the necessary conditions. This picture is confirmed by semianalytical scaling laws and 3D particle-in-cell simulations. Our results show that laser-plasma interaction can drive itself towards this type of laser wakefield acceleration even if the initial laser and plasma parameters are outside the required regime.

Thomson-backscattered x rays from laser-accelerated electrons.

We present the first observation of Thomson-backscattered light from laser-accelerated electrons. In a compact, all-optical setup, the "photon collider," a high-intensity laser pulse is focused into a pulsed He gas jet and accelerates electrons to relativistic energies. A counterpropagating laser probe pulse is scattered from these high-energy electrons, and the backscattered x-ray photons are spectrally analyzed. This experiment demonstrates a novel source of directed ultrashort x-ray pulses and additionally allows for time-resolved spectroscopy of the laser acceleration of electrons.

Laser-plasma acceleration of quasi-monoenergetic protons from microstructured targets.

Particle acceleration based on high intensity laser systems (a process known as laser-plasma acceleration) has achieved high quality particle beams that compare favourably with conventional acceleration techniques in terms of emittance, brightness and pulse duration. A long-term difficulty associated with laser-plasma acceleration--the very broad, exponential energy spectrum of the emitted particles--has been overcome recently for electron beams. Here we report analogous results for ions, specifically the production of quasi-monoenergetic proton beams using laser-plasma accelerators. Reliable and reproducible laser-accelerated ion beams were achieved by intense laser irradiation of solid microstructured targets. This proof-of-principle experiment serves to illuminate the role of laser-generated plasmas as feasible particle sources. Scalability studies show that, owing to their compact size and reasonable cost, such table-top laser systems with high repetition rates could contribute to the development of new generations of particle injectors that may be suitable for medical proton therapy.

[Doppler ultrasound of precerebral arteries. A retrospective study of referral routines and findings]. / Ultralyddopplerundersøkelse av precerebrale arterier. En retrospektiv gjennomgang av henvisningsrutiner og ultralydfunn.

This study reports the activities of the cerebrovascular laboratory at Ullevål hospital in 1990. 713 patients (332 men and 381 women; mean age 60 years) were examined with pulsed Doppler ultrasound. Pathological findings were detected in 202 patients (28%). Among these, 43 patients (6%) had stenosis in the internal carotid artery < 70%, 31 patients (4.3%) stenosis > or = 70% and 30 patients (4.2%) had occluded internal carotid artery. 48 patients (6.7%) had stenosis of the external carotid artery. Subclavian steal was detected in 16 patients (2.2%), stenosis in the subclavian artery without steal in 12 patients (1.7%), and atypical or suspect pathological signals from the vertebral artery in 22 patients (3.1%). The occurrence of pathological ultrasound findings was strongly related to the reasons for referral. There were pathological ultrasound findings in 77% of the cases with symptomatic neck bruit. No pathological findings were detected in patients < 50 years who were referred for ultrasound examination because of vertigo. Most patients were referred by the Department of Neurology (n = 386), but relatively few patients (16%) had pathological ultrasound findings. The occurrence of pathological findings in patients referred from other hospital departments (n = 131) and general practitioners (n = 84) was 53% and 44%, respectively.

[Treatment of writer's cramp with botulinum toxin]. / Behandling av skrivekrampe med botulinumtoksin.

Writer's cramp is a focal dystonia that is resistant to most treatment regimens. This article describes two patients with writer's cramp who were successfully treated with botulinum toxin injections into the forearm muscles. Transient weakness due to the effect of botulinum toxin was registered in the injected muscles. No other side effects were observed. The beneficial effect of a single injection lasted from three to four months and could be reproduced by repeated injections over a three year follow-up period. We conclude that botulinum toxin injections may provide safe and effective treatment in selected patients with writer's cramp.

The effect of 8 years of strict glycaemic control on peripheral nerve function in IDDM patients: the Oslo Study.

We have investigated the effect of long-term strict glycaemic control on peripheral and autonomic nerve function in 45 IDDM patients (age 18-42 years, diabetes duration 7-23 years) without clinical signs of neuropathy or other neurological disease. They were randomly assigned to treatment either with continuous insulin infusion, multiple injections (4-6 times daily), or conventional treatment (twice daily) for 4 years and followed prospectively for 8 years. Motor and sensory nerve conduction velocities were measured at the start and after 8 years. Autonomic nerve function tests were performed only once, after 8 years. A significant reduction of nerve conduction velocity was observed during 8 years in patients with mean HbA1 more than 10% (n = 12, group mean 10.9%, range 10.1-13.2%) compared to patients with HbA1 less than 10% (n = 33, group mean 9.0%, range 7.5-9.9%). Change of motor nerve conduction velocity in the peroneal nerve was: -4.8 +/- 4.9 (SD) vs -2.2 +/- 5.3 m/s (p < 0.01). Change of motor nerve conduction velocity in the posterior tibial nerve was: -6.8 +/- 5.7 vs- 3.9 +/- 5.1 m/s (p < 0.05). No significant changes were observed in the ulnar nerve. Change of sensoric nerve conduction velocity in the sural nerve was: -8.9 +/- 8.0 vs -4.6 +/- 5.3 m/s (p < 0.05). Multiple regression analysis showed that a change in HbA1 of 1% resulted in a 1.3 m/s change in nerve conduction velocity during 8 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Grading stenoses of the internal carotid artery by estimation of blood velocity with pulsed Doppler ultrasound.

The relationship between blood velocity and residual lumen diameter at the origin of 100 internal carotid arteries was studied. The diameter was measured by angiography and blood velocity by relatively simple Doppler ultrasound equipment. A scatter diagram between maximal velocity and diameter was used to construct a table on the sensitivity and specificity of various cutoff values for maximal velocity to diagnose stenoses of different degrees. A maximal velocity > or = 0.8 m/s had a sensitivity of 87% and a specificity of 93% to diagnose stenoses with a diameter < or = 3 mm (i.e. more than 50% diameter reduction). Thus, simple recording of maximal velocity can be used as a reliable screening method to detect patients with high- and medium-grade stenosis. Analysis of the spectral spreading of velocities across the lumen of a stenosis, or estimation of percent stenosis from the velocity in a stenosis and that in a poststenotic segment, were in our hands less useful for this purpose. None of the methods were good to detect or exclude the presence of low-grade stenosis.

Radiological assessment of stenosis of the internal carotid artery at the junction with the common.

Stenoses at the origin of 100 internal carotid arteries from patients with ischemic cerebrovascular disease were studied by intra-arterial angiography. Three principles were employed to evaluate the degree of stenosis: 1) verbal description, grading stenoses as mild, moderate of severe, 2) estimation of the true residual diameter, and 3) calculation of percent stenosis, defined here as the diameter of the artery at the origin relative to that at the level of the angle of the mandible. The true diameter, estimated to the nearest whole mm, corresponded well with the verbal description, and correlated significantly with percent stenosis. Since the true diameter is precisely defined, easy to estimate, and directly related to its hemodynamic effect, we suggest that this simple parameter, rather than the more commonly used, but more vaguely defined term "percent lumen reduction", is used to grade stenoses of the internal carotid artery.

[Stenosis of the internal carotid artery at the bifurcation. Radiologic definition and Doppler diagnosis]. / Stenose av arteria carotis interna ved carotisbifurkaturen. Radiologisk definisjon og dopplerdiagnostikk.

One hundred internal carotid arteries with varying degrees of stenosis were studied by angiography and doppler ultrasound. We found the minimal diameter of a stenosis, measured in mm, more suitable as reference for the doppler-based method than verbal assessment of a stenosis as slight, moderate or pronounced. The sensitivity and specificity of maximal blood velocity to diagnose high-grade stenosis is satisfactory for screening patients who might benefit from endarterectomy. Spectral velocity spread, or comparison of the velocity in the stenosis with that of a cranial reference segment of the artery did not increase the sensitivity to detect low-grade stenoses.

A double-blind comparison of citalopram (Lu 10-171) and amitriptyline in depressed patients.

In a controlled, clinical, multicentre trial comprising a total of 43 patients (17 men and 26 women) citalopram was compared double-blindly with amitriptyline. Nineteen patients of each group were classified as endogeneously depressed, whereas four patients of the citalopram group and one of the amitriptyline group were classified as non-endogenously depressed. The patients were seriously ill with a high frequency of previous depressive episodes and of mental disorders among their closest relatives. Thirteen of the patients in either group had received antidepressants without satisfactory effect before entry into the trial. Each patient was treated for a period of at least 3 weeks with daily citalopram doses of 30-60 mg or daily amitriptyline doses of 75-225 mg. A statistically significant reduction of MADRS scores (total scores as well as each of the 10 individual items) was recorded in both groups. The only difference between the groups was a trend towards a better effect on sleep disturbances in the amitriptyline group. Side-effects were recorded more frequently in the amitriptyline group than in the citalopram group, global assessment of side effects being significantly different in favour of citalopram. It is concluded that citalopram is an effective and safe drug in the treatment of endogenous depression - probably as efficacious as amitriptyline, but with fewer side effects.

Zuclopenthixol decanoate in schizophrenia: serum levels and clinical state.

Serum concentrations of zuclopenthixol were determined in a group of 20 patients treated with a depot preparation, zuclopenthixol decanoate in Viscoleo. Clinical assessments according to a Clinical Global Impression (CGI) scale, Comprehensive Psychological Rating Scale (CPRS), 16-item subscale for schizophrenia, and the UKU side effect scale were performed on 3 consecutive days of injection. The serum concentrations showed a limited individual variation and a high and significant correlation between dose and serum concentration. One patient had a particularly high serum concentration of zuclopenthixol. This patient also had an elevated concentration of the N-dealkyl metabolite, but a low concentration of the sulphoxide. For serum concentrations versus clinical state and side effects some significant correlations were found. All correlations were positive, which means that the higher the serum concentration the poorer the clinical state of the patient. We think that this probably reflects a common clinical pattern of increasing the dose, when the antipsychotic response is unsatisfactory. The study also showed that for moderately ill patients, who were given the optimum dose of drug, the subgroup of patients not experiencing side effects had significantly lower serum concentrations than the subgroup with side effects.

[Acute local cold injury]. / Bemerkungen zum akuten örlichen Kälteschaden.

Whereas reasonable rewarming is the successful treatment in the Alpine regions of Europe, rapid rewarming in a whirlpool at a water temperature of 35 degrees C is given preference in the Soviet Union and in the U.S.A. Subsequently, perfusion of the tissue must be maintained by sympathetic blockades, infusions of low-molecular-weight dextrans and improving the microcirculation. Since no third-degree or fourth-degree local cold injury will heal without sequelae, particular attention should be focused on preventive measures.