International collaboration: Will it be keeping alive East European research?

International scientific collaboration is very sensitive to political and economic changes in a country or a geopolitical region. Collaboration in research is reflected by the corresponding coauthorship of the published results which can be analysed with the help of bibliometric methods. Based on data from theScience Citation Index (SCI), the change of annual international coauthorship patterns ofBulgaria, Czechoslovakia, Hungary, Poland andRomania have been analysed for the periods 1981–1985 and 1984–1993, respectively. It is shown that international collaboration was not developing similarly in the countries under study. Whilst scientific communities of Hungary and Poland have already been opening in the early 80s, the international collaboration of the other East-European countries was still dominated by COMECON relations till 1989. As expected, since 1990 an increasing scientific collaboration with highly developed countries can be observed in all five countries. At the same time, scientific collaboration with the former communist countries shows a clear decline. The great share of international co-authorship links is some countries reflect various tendencies part of which are interpreted with the help of a cardiologic model.     

Stability Testing of Clinical Samples

The stability program for clinical samples as presented is based on the ICH Tripartite Guideline for Stability Testing of New Drug Substances and Products and the same principles that the program followed throughout the development of a drug product. But the Guideline and the basic principles were adapted to deal with the specific problems encountered with clinical samples. The expiration dates represent minimum shelf lives, storage conditions, and storage periods, and the minimum shelf lives correspond the duration of the clinical trials in phases I to III. Shelf lives are established on the basis of stress and accelerated tests to provide all batches with an open expiration date. They are supported and confirmed by long-term tests conducted under the storage conditions presenting climate zone II, 25°C/60% RH. The self lives determined apply to all the batches of the relevant development stage, although only the batches in the final phase of development originate from a validated manufacturing phase. For different dosages, dosage forms, and packaging materials, the number of batches and analysis is reduced by scientifically based rationalization measures such as bracketing and matrixing. The stability results obtained with clinical samples are a major factor for achieving a comprehensive assessment of the quality of a finished medicinal product. In this way it is possible to establish a link between the quality of clinical batches for phases I-III and the quality of the finished drug product.     

Dissolution Behavior of Griseofulvin Solid Dispersions Using Polyethylene Glycol, Talc, and Their Combination as Dispersion Carriers

Griseofulvin solid dispersions were prepared using polyethylene glycol 6000 (PEG), talc, and their combination as carriers by the solvent method. The dissolution of griseofulvin from these dispersions was studied. It was found that in these carriers the drug dissolution rate was a function of drug loading. The dissolution rate from dispersions prepared using PEG was similar to that from PEG/talc dispersions, especially at a low percentage of drug loading. Dispersions of PEG and PEG/talc provided dissolution rates faster than those from dispersions of talc. The incorporation of talc in PEG yielded dispersions with properties of less tackiness and ease for handling. Dissolution kinetics, based on the Hixson-Crowell equation, was used to determine the characteristics of griseofulvin particles in dispersions. Linear relationships were obtained for PEG and PEG/talc dispersions that indicated the presence of a uniformly sized monoparticulate system, whereas deviation from linearity was observed for talc dispersions. This appeared to be a multiparticulate system in which particles were present as free form and adsorbed form on the surface of talc.     

Unrestricted Hartree-Fock approximation of the extended emery model

We use an unrestricted self-consistent Hartree-Fock approach to calculate the nature of doping states in the three-band Hubbard model. It turns out that for physically relevant parameter values one hole is localized within a small spin-polarized region where five Cu spins are aligned in the same direction. The spin polarization and binding energy between these spinpolaronic states are investigated as a function of different parameters including a Holstein-type electron-phonon coupling on the Cu sites. At higher doping concentration we observe the occurrence of afmon states where the holes are localized in a ring-shaped area. Inside this ring the antiferromagnetic order parameter has inverse sign with respect to the residual antifer-romagnetically ordered plane.     

Dipole radiation in uniaxial bianisotropic medium

Radiation from an electric dipole oriented parallel to the distinguished axis of a uniaxial bianisotropic medium is considered. The electromagnetic fields are represented in full generality in terms of two scalar Hertz potentials. An analytic solution for these scalar potentials is obtained.<>     

Automatic detection of mass-resolved ion conics

A processing algorithm for automatically detecting a specific type of ion distribution (called the ion conic distribution) in data obtained from a space-based mass spectrometer has been devised. Automation of this task is necessary due to the sparseness of conic events within the very large databases typical of space plasma instruments. The algorithm used to perform this automated analysis and the methods used to verify the algorithm are described. Initial results on the characterization of the near-Earth space plasma are summarized     

Effects of magnetic resonance imaging on cardiac pacemakers and electrodes

In phantom studies we investigated the effects of magnetic resonance imaging (MRI) on pacemakers and electrodes. Twenty-five electrodes were exposed to MRI in a 1.5T scanner with continuous registration of the temperature at the electrode tip. Eleven pacemakers (five single chamber and six dual chamber) were exposed to MRI. Pacemaker output was monitored to detect malfunction in VOO/DOO and VVI/DDD modes. A temperature increase at the electrode tip of up to 63.1 degrees C was observed during 90 seconds of scanning. In seven electrodes the temperature increase exceeded 15 degrees C. Although no pacemaker malfunctions were observed in asynchronous pacing mode (VOO/DOO), inhibition and rapid pacing were observed during spin-echo imaging if the pacemakers were set to VVI or DDD mode. Pacemaker function was not impaired during scanning with gradient-echo sequences. Next to pacemaker dysfunction, electrode heating has to be considered a possible adverse effect when exposing patients with pacemakers to MRI.     

Short-term preoperative radiotherapy results in down-staging of rectal cancer: a study of 1316 patients

OBJECTIVE: The incidence of back pain in children in our country is unknown. Several causes can produce this symptom, but it is necessary to rule out pathologies that require specific treatments. The goal of this work was to study the incidence and the etiology of back pain in children in our country. PATIENTS AND METHODS: We present a prospective study done in our Orthopedic Department during a period of 7 months. Twenty-two patients were referred with back pain of at least two months duration. The incidence was 2.9% compared to the total number of patients. The average age ranged from 7 to 17 years. RESULTS: A careful history and a radiological examination diagnosed 50% (11 cases) of the causes of backache in the present study. An idiopathic etiology was the most frequent cause and represented 9 patients (41%). In the remaining 12 cases (59%) pathological causes that required special treatment were identified including 2 cases of Scheuermann disease, 4 cases of painful scoliosis, 3 spondylolysis with spondylolisthesis, 2 cases of discitis, 1 benign neoplasm and 1 psychogenic cause. CONCLUSIONS: We recommend conservative management with the use of medication for relief of pain and physical therapy in the idiopathic cases. In the remaining cases, the specific treatment of the disease can improve the back pain.     

Apoptosis in the failing human heart

BACKGROUND: Loss of myocytes is an important mechanism in the development of cardiac failure of either ischemic or nonischemic origin. However, whether programmed cell death (apoptosis) is implicated in the terminal stages of heart failure is not known. We therefore studied the magnitude of myocyte apoptosis in patients with intractable congestive heart failure. METHODS: Myocardial samples were obtained from the hearts of 36 patients who underwent cardiac transplantation and from the hearts of 3 patients who died soon after myocardial infarction. Samples from 11 normal hearts were used as controls. Apoptosis was evaluated histochemically, biochemically, and by a combination of histochemical analysis and confocal microscopy. The expression of two proto-oncogenes that influence apoptosis, BCL2 and BAX, was also determined. RESULTS: Heart failure was characterized morphologically by a 232-fold increase in myocyte apoptosis and biochemically by DNA laddering (an indicator of apoptosis). The histochemical demonstration of DNA-strand breaks in myocyte nuclei was coupled with the documentation of chromatin condensation and fragmentation by confocal microscopy. All these findings reflect apoptosis of myocytes. The percentage of myocytes labeled with BCL2 (which protects cells against apoptosis) was 1.8 times as high in the hearts of patients with cardiac failure as in the normal hearts, whereas labeling with BAX (which promotes apoptosis) remained constant. The near doubling of the expression of BCL2 in the cardiac tissue of patients with heart failure was confirmed by Western blotting. CONCLUSIONS: Programmed death of myocytes occurs in the decompensated human heart in spite of the enhanced expression of BCL2; this phenomenon may contribute to the progression of cardiac dysfunction.