Micro- and macrosocial conditions of adolescents' aggressiveness and antiforeigner attitudes.
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Adolescent↗
Biomedical subjects
M Hofer
Publications and source records attributed to M Hofer.
Effects of postirradiation carboxymethylglucan administration in mice.
The hemopoiesis-enhancing ability of a soluble glucan derivative, i.e. carboxymethylglucan (CMG), was investigated in gamma-irradiated mice. Attention was focused on the usefulness of its single or repeated postirradiation administration. CMG was administered i.p. at (a) single dose of 6 mg 2 h postirradiation, (b) four 6 mg doses in the first 4 days postirradiation, (c) four 1.5 mg doses at the same time intervals. Indices of granulopoiesis and inflammatory side effects (liver weight increase and hepatic granulomas) were investigated in mice irradiated with a sublethal dose of 7 Gy. All three CMG-treated groups of mice were found to exhibit enhanced hemopoietic recovery in comparison with the controls. Although the mice repeatedly given the 6 mg CMG doses showed the most rapid recoveries of all the evaluated parameters of granulopoiesis, the most pronounced hepatic side effects were found in these mice, too. When survival of mice was recorded in lethally (9 Gy) irradiated animals, the best protective response were obtained following the repeated administration of the 1.5 mg CMG dose, the survival by day 30 in this group being significantly higher not only in comparison with the controls but also with the mice repeatedly given the 6 mg dose of CMG. The results suggest that the postirradiation CMG administration can be useful for enhancing radiation suppressed hemopoiesis. However, repeated larger CMG doses may produce side effects which compromise the overall survival of irradiated mice.
Animals↗
[Contrast-enhanced color-coded duplex ultrasound of high grade carotid stenoses].
PURPOSE AND METHODS: The usefulness of SH-U-508A (Laevovist) in the quantification of high-grade internal carotid stenosis (ICA) is assessed in this study. 32 patients with high-grade ICA stenosis (> = 70%) or occlusion are examined using colour Doppler-assisted duplex imaging (CDDI) before and after injection of SH-U-508A. RESULTS: The SH-U-508A-induced increase in blood echogenicity started at 9.8 s (mean; SD: 2.2) after bolus injection and peaked at 21 dB (mean; SD: 1.9; n = 12) after 14.8 s (mean; SD: 2.9). In addition, SH-U-508A led to a significant increase in systolic peak velocity determined in the common carotid artery, by 26% (mean; SD: 9; p < 0.05). Significant differences between non-enhanced and enhanced CDDI were found for the visualisation of the entire length of the intrastenotic residual lumen (43% vs 83%; p < 0.01). Correlations between non-enhanced and enhanced CDDI were high (r > 0.9) for the determination of cross-sectional area reduction and plaque length. CONCLUSION: SH-U-508A may be useful in quantifying high-grade ICA stenoses with insufficient delineation at non-enhanced CDDI.
Aged↗
[Possibilities of the use of MR tomography-based cerebral blood volume maps in the diagnosis of brain tumors].
PURPOSE: Today contrast enhanced MR imaging is a reliable method for detecting mostly distinguishing between different histological types of tumours. In this study we use a MR-based method to measure the regional cerebral blood volume (rCBV). Using this technique we try to judge the grading and vitality of the tumours. METHODS: 26 patients with various types of brain tumours were examined. To calculate rCBV-maps of one slice, low-dosed Gd-DTPA was injected as a bolus. Using the relaxation effect the obtained signal intensity-time curves were converted pixel-wise into rCBV images. For the tumours rCBV-ratios were calculated relative to the corresponding area in the contralateral hemisphere. RESULTS: In the investigated group all tumours were detected on the basis of a raised rCBV-ratio. Since only vital parts of the tumour are perfused, the rCBV maps may be used to determine the place of biopsy. CONCLUSIONS: The differential diagnosis of all histological tumour types was not possible on the basis of rCBV values. Distinction between low grade and high grade gliomas was also not significant. However, a low grade glioma can be excluded if the morphological images definitely indicate an astrocytoma and if the rCBV-ratio was higher than 2.
Adult↗
Enhancement by carboxymethylglucan of early cellular damage in 1 Gy-irradiated mice.
Our results describe a novel carboxymethylglucan (CMG) activity, namely its radiosensitizing effect on early cellular damage in mice gamma-irradiated with a dose of 1 Gy. An increase of thymidine levels in blood plasma, determined 4 h after irradiation, was used as an indicator of the early cell death. The radiosensitizing effect was observed when administering CMG at time intervals close to irradiation time (1 h before to 1 h after irradiation). Diclofenac (an inhibitor of prostaglandin production) had no modifying effects on elevation of plasma thymidine levels induced by radiation or radiation + CMG. Pentoxifylline (an inhibitor of synthesis of tumour necrosis factor and of phosphodiesterase) administration elevated plasma thymidine to similar levels as CMG alone, combined pentoxifylline + CMG treatment had not additive effects.
Animals↗
Radioprotection of mouse hemopoiesis by dipyridamole and adenosine monophosphate in fractionated treatment.
The purpose of the studies reported here was to investigate the ability of the combined administration of dipyridamole and adenosine monophosphate, drugs known to elevate extracellular adenosine, to protect mice undergoing treatment with fractionated irradiation (five doses of 2 or 3 Gy each) given at 24-h intervals. Based on observations of hemopoietic recovery (endogenous hemopoietic spleen colony formation, marrow granulocyte-macrophage colony-forming cells, peripheral blood cells) after the completion of fractionated irradiation and on survival studies, it was demonstrated that the repeated administration of the drugs 60 min before each of the radiation fractions mitigates the hemopoietic injury and enhances the survival of mice irradiated with an additional "top-up" dose. It could be deduced that the single protective actions of the drugs retain their efficacy in repeated treatment and enhance the sparing effect of dose fractionation on hemopoiesis. Interestingly, the toxic side effects of the drugs tend to decrease when they are administered repeatedly, probably due to the development of tolerance to their cardiovascular action. This reduction in toxicity offers benefit with respect to the potential use of these hemopoiesis-protecting drugs in clinical radiotherapy.
Adenosine Monophosphate↗
Haemopoiesis-enhancing effects of repeatedly administered carboxymethylglucan in mice exposed to fractionated irradiation.
Carboxymethylglucan (CMG), a water-soluble glucan derivative, enhanced the number of granulocytes in the peripheral blood as well as other indices of haemopoietic recovery (total cellularity and the number of granulocyte-macrophage progenitor cells in femoral marrow, spleen weight) investigated after fractionated gamma-irradiation in mice (five doses of 2 Gy each, or three, four and five doses of 3 Gy each given at 24-h intervals). An increased liver weight and a more pronounced anaemia found in the CMG-treated mice suggested, however, that also inflammatory side effects were evoked by the repeated administration of CMG. On the other hand, the development of tolerance, i.e., a decreased effectiveness of the treatment with CMG upon its repeated administration, did not seem to play any major role under the experimental conditions studied, because the protective effects of CMG increased with the increasing number of CMG injections.
Adjuvants, Immunologic↗
Radioprotective efficacy of dipyridamole and AMP combination in fractionated radiation regimen, and its dependence on the time of administration of the drugs prior to irradiation.
We have recently demonstrated that the combined administration of dipyridamole and adenosine monophospate to mice induces radioprotective effects in terms of postirradiation haemopoietic recovery in animals irradiated with a single dose. The aim of the present experiments was to investigate the radioprotective ability of the drug combination under conditions of fractionated radiation treatment. It has been shown that administration of drugs either 15 or 60 min before each of the five daily 3-Gy doses of gamma-radiation enhances haemopoietic recovery and survival of mice exposed to an additional "top-up" dose of 3.5 Gy. Furthermore, it has been ascertained that the regimen using administration of the drugs 60 min prior to irradiation is more effective than administration of the drugs 15 min prior to irradiation. Due to the evidence that administration of the drugs 15 min prior to irradiation protects the organism mainly via mechanisms of systemic hypoxia while the pretreatment 60 min before irradiation avoids the role of hypoxia and mainly induces cell proliferation effects, our results suggest a more effective protective role of mechanisms stimulating haemopoiesis under conditions of fractionated radiation. The data may provide a basis for more rational use of radioprotection in fractionated radiation regimens.
Adenosine Monophosphate↗
Ionotropic glutamate-receptor gene expression in hypothalamus: localization of AMPA, kainate, and NMDA receptor RNA with in situ hybridization.
In situ hybridization and Northern blots were used to study the ionotropic subtypes of the glutamate receptor in the rat hypothalamus. Widespread expression of AMPA, kainate, and NMDA receptor RNA was found in the hypothalamus with the transcripts the same size and number as found in other regions of the brain. Most of the glutamate-receptor subunits studied were expressed in greater amounts in hippocampus than in hypothalamus; GluR5, on the other hand, showed a greater expression in hypothalamus than in hippocampus. On the basis of Northern blot analysis, all regions of the brain examined, including hypothalamus, cerebral cortex, cerebellum, olfactory bulb, and hippocampus, expressed all eight of the subunits studied. Each subunit showed different relative expressions in the different regions. In the hypothalamus, GluR1 and GluR2 were among the most widely expressed of the non-NMDA ionotropic receptors. Other AMPA-preferring receptors, GluR3 and -R4, were also found, but to a lesser extent. Scattered cells expressed the kainate-preferring receptors GluR5, -R6, and -R7. The NMDA receptor NMDAR1 was detected throughout the hypothalamus. In many regions of the hypothalamus, only scattered cells showed detectable expression of the glutamate-receptor mRNA as detected by autoradiographic silver grains over neurons; unlabeled cells were mixed among labeled cells. Every region of the hypothalamus had several different glutamate receptors. The expression of many different types of ionotropic glutamate receptors throughout the hypothalamus suggests that multiple modes of ion channel regulation by glutamate probably operate here and provides further support for the importance of the excitatory transmitter glutamate in hypothalamic regulation.
Animals↗
A new phage typing scheme for Proteus mirabilis and Proteus vulgaris strains. 1. Morphological analysis.
A new bacteriophage typing set, composed of 22 phages, was established as a tool for differentiation of Proteus strains. All the phages were tailed and included 4 morphological types (A1, A2, B1 and C1). They were classified into the families Myoviridae, Siphoviridae and Podoviridae. From the set, 19 phages had double-stranded DNA and 3 were single-stranded DNA phages.
Bacteriophage Typing↗
Effects of sublethal irradiation with helium ions (300 MeV/nucleon) on basic hematological parameters of mice.
The aim of the experiment was to obtain new knowledge on the biological effectiveness of high-energy (300 MeV/nucleon) helium ions, which represent a part of the spectrum of cosmic rays. Male (CBA x C57BL)F1 mice, 4 months old, were exposed to a dose of 4 Gy helium ions (exposure rate 0.05 Gy/min). As a comparative standard irradiation the same dose of 4 Gy of 137Cs gamma-rays (exposure rate 0.07 Gy/min) was used. Material sampling was performed 6-8 h, 4 days and 9 days after irradiation for both experimental groups mentioned above. There were 7 animals in each group including the control group of non-irradiated mice. Eight basic hematological parameters of peripheral blood, bone marrow, spleen and thymus were studied. On day 4 after the irradiation with helium ions, the values of leukocyte counts in peripheral blood, bone marrow cellularity and spleen cellularity were reduced to about 10% of the respective control values while the decline after irradiation with gamma-rays amounted to about 50%. These and other results presented reflect a high relative biological effectiveness of 300 MeV/nucleon helium ions.
Animals↗
Regulation of N-methyl-D-aspartate (NMDA) receptor function during the rearrangement of developing neuronal connections.
There is evidence from a number of studies that the molecular and biophysical properties of NMDA receptors are altered during normal development. A temporal correlation with changes in NMDA receptor efficacy and periods of synaptic plasticity has been demonstrated in several systems, suggesting that NMDA receptors have a critical function in determining periods of synaptic plasticity. Data from our laboratory demonstrate reduced NMDA sensitivity of the tectal evoked potential following chronic application of NMDA to the tadpole tectum, a treatment that may mimic a naturally occurring mechanism for limiting neuronal plasticity to certain stages of development. Our analysis of the expression pattern of mRNA coding for various glutamate receptor subunits in the rat retinocollicular system establishes that differential regulation of NMDA receptor subunits at the mRNA level could be a molecular basis for changes in biophysical and pharmacological properties of the NMDA receptor complex. However, even though the NMDA receptor is the best studied candidate to function as a 'plasticity switch', there are large gaps in our understanding of the complete set of factors that control the ability of synapses to rearrange during development.
Animals↗
Regulation of NMDA receptor mRNA during visual map formation and after receptor blockade.
The topographic refinement of the rat retinocollicular projection is dependent on normal NMDA receptor function. Here we examined the expression of NMDA and non-NMDA glutamate receptor mRNA in the rat superior colliculus (SC) during this postnatal refinement period. The temporal expression pattern of mRNA coding for the NMDA receptor subunit NR1 in the superficial SC followed the time course of collicular synaptogenesis. A pronounced increase of NR1 mRNA levels occurred during the late stages of retinocollicular map refinement. In cortex, the time course of the expression of NR1 mRNA in cortex was found to be similar to that observed in SC, with low levels during the first postnatal week, a maximum at P19, and a decrease thereafter. In SC, but not in cortex, there was a change in the ratio of the two NR1 transcripts during the second postnatal week that parallels a previously demonstrated developmental change in the mean open time of NMDA channels in collicular neurons. In contrast, the mRNA expression pattern of the non-NMDA receptor subunit GluR2 in the developing SC was not closely correlated with synaptic changes. Chronic treatment of the SC with the NMDA receptor antagonist 2-amino-5-phosphonovalerate (APV) for 12 or 19 days, which disrupts retinocollicular map formation, appears to block the developmental rise in NR1 mRNA levels. These findings support a specific role for the NMDA receptor subtype of glutamate receptors in the control of synaptogenesis and developmental plasticity in the SC.
2-Amino-5-phosphonovalerate↗
[Intracranial MR angiography].
Magnetic resonance angiography (MRA) is gaining wide acceptance as a screening modality for the intracranial vasculature. Previous reports have demonstrated that MRA is capable of accurately depicting the normal vascular anatomy and anatomic variants. To date various techniques have been applied in the evaluation of vaso-occlusive disease, aneurysms, arteriovenous malformations and venous sinus thrombosis. Recent technical developments have significantly improved spatial resolution and vascular contrast and will further enhance its routine clinical use. The purpose of this essay is to summarize the technical approaches, clinical role and limitations of MRA as they apply to the intracranial circulation.
Blood Flow Velocity↗
Redefining care delivery: a modular system.
Personnel from all departments involved in patient care--nursing and ancillary--redefined a care delivery system. This pilot study defines committee and modular formation, physical changes, communication and goals of the modular system.
Communication↗
Brief report: disseminated osteomyelitis from Mycobacterium ulcerans after a snakebite.
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Base Sequence↗
Hematopoietic recovery in repeatedly irradiated mice can be enhanced by a repeatedly administered combination of diclofenac and glucan.
A combination of diclofenac and glucan administered repeatedly in a protective regimen in the course of repeated gamma irradiation of mice (6 x 2 Gy during 3 weeks) enhanced granulopoiesis and other indices of hematopoietic recovery investigated from 3 to 7 days after the last radiation exposure. Repeated administration of diclofenac or glucan alone or treatment of the mice with the diclofenac-glucan combination given once before the first or the last radiation exposure did not induce such effects. The protective effect of the repeatedly administered combination of the drugs was realized despite the fact that the response of the serum colony-stimulating activity to the repeated combined drug administration was decreased at the end of the treatment regimen compared to that of mice given this drug combination only once. The combined treatment is supposed to act via increased proliferation of the hematopoietic stem or progenitor cells. Additivity or even synergism of the hematostimulatory action of glucan and of the strengthening of positive control of cell proliferation achieved by removing negatively acting prostaglandins (diclofenac action) may account for the radioprotective effects observed.
Animals↗
Childhood tuberculosis at a Swiss university hospital: a 2-year study.
The incidence of tuberculosis (TB) presenting to the University Hospital, Geneva, Switzerland, was studied over 2 years. Clinical data on all children receiving antituberculous drug therapy was collected. Of the 43 identified cases, 42% had active disease (i.e. clinical evidence of organ involvement), the remaining 58% being asymptomatic. All 43 children originated from countries other than Switzerland. Symptomatic, drug induced hepatitis necessitated temporary interruption of therapy in 2 children (5%). Contact screening yielded three new cases of pulmonary TB, three previously diagnosed cases and seven instances of a positive medical history in relatives living in other countries. Of the 34 families in this study, contact screening could not be completed in 8. The results of this study indicate that children with TB are primarily associated with families originating from countries other than Switzerland, particularly those in which TB remains endemic. Tuberculin skin testing should therefore be targeted at this group. Contact tracing has also been shown to be beneficial.
Adolescent↗