Binding of girisopam (a 2,3-benzodiazepine derivative) to the substantia nigra is prevented by lesioning of the striatonigral pathway

The binding sites of girisopam, a homophthalazine (2,3-benzodiazepine)-derivate have a specific distribution pattern restricted to the striato-pallido-nigral system of the rat brain. Following kainic acid lesions in the caudate-putamen or the ventral striatum (nucleus accumbens, olfactory tubercle), as well as after surgical transection of the striatonigral pathway, [3H]girisopam binding sites were reduced or completely eliminated from the substantia nigra and the entopeduncular nucleus. Kainic acid lesions of the globus pallidus failed to act on girisopam binding sites in the substantia nigra. Surgical transections or 6-hydroxydopamine lesions of the striatonigral pathway, as well as intranigral kainic acid injections did not influence binding sites in the striatum or the pallidum. These findings indicate that girisopam in the striatum to be postsynaptic on striatonigral projecting neurons. Girisopam in the striatum seems is present in striatonigral projecting neurons. The binding sites are transported from the striatum (mainly from the caudate-putamen, partly from the ventral striatum) to the substantia nigra and the entopeduncular nucleus. The exact identity of these striatonigral fibres bearing homopthalazines is uncertain.

Sensorimotor impairments in rats with cerebral infarction, induced by unilateral occlusion of the left middle cerebral artery: strain differences and effects of the occlusion site

Enormous differences exist between rat strains with respect to the infarct volume induced by unilateral middle cerebral artery (MCA) occlusion. We performed three experiments to address the following questions. Firstly, whether the pattern of MCA-occlusion (MCA-O) induced sensorimotor impairments in rats are strain dependent; secondly, whether proximal (i.e., close to its origin) and distal occlusions (above the lenticulostriate branch) of the MCA affect infarct volume and the behavioral impairments to a different extent; and thirdly, whether there is a relationship between the infarct volume and behavioral deficits. We found that the pattern of sensorimotor malfunctions induced by proximal unilateral MCA-O were highly strain dependent. Of the eight strains tested, Winkelmann-Wistar rats, Spontaneously Hypertensive Stroke-Prone rats, and Wistar-Kyoto rats were most severely affected. By contrast, Brown-Norway rats showed only mild behavioral deficits after the MCA-O. The second experiment confirmed that proximal occlusions induced slightly more behavioral malfunctions than distal occlusions did. Histological evaluation of the brain damage caused by proximal and distal MCA-O, confirmed that distal MCA-O damaged nearly exclusively cortical areas, and spared the caudate/putamen. An exploratory analysis of the relationship between infarct volume and behavioral deficits did not indicate that the severity of sensorimotor malfunctions can be predicted from the size of the infarct.

Sensorimotor impairments in Wistar Kyoto rats with cerebral infarction, induced by unilateral occlusion of the middle cerebral artery: recovery of function

Wistar Kyoto (WKY) rats with cerebral infarction induced by permanent unilateral occlusion of the middle cerebral artery (MCA) and sham-operated rats were tested in a series of simple behavioral test 2, 16 and 37 days after surgery. In addition, the motility of the animals was measured over a period of 62 h, after the third test series. A subset of the tests appeared to be suitable to assess the effects of cerebral infarction, namely, grasping reflex of contralateral hindpaw, circling behavior, forelimb flexion, hindlimb flexion, and latency to fall off a square bridge. Except for the impaired grasping reflex of the contralateral hindpaw, there was spontaneous complete recovery of function by the third test session, 37 days after surgery. Some of the other tests might not have been sensitive enough to detect the effects of the unilateral MCA-occlusion (MCA-O) on behavior. Moreover, the WKY rats were very inactive in some of the tests, so that reliable scoring of the effects was not always possible. A rat strain other than the WKY strain might be more suitable to study the behavioral consequences of MCA-O.

Functional cerebral activity during regeneration from entorhinal lesions in the rat

The consequences of an unilateral electrolytic entorhinal lesion on the functional activity in all major anatomically defined brain regions were evaluated in the rat. The 14C-2 deoxyglucose method served as a tool to quantify alterations of local cerebral glucose utilization (LCGU) ipsilateral and contralateral to the lesion at 4 days, 2 weeks, or 3 months after stereotaxic surgery. Apart from a few minor increases in the contralateral hemisphere, the predominant pattern consisted of reductions in the range of 10-40% in the ipsilateral hemisphere. Ipsilaterally, in extrahippocampal areas, LCGU had regained control levels at 2 weeks postlesion in contrast to hippocampal regions, where reductions were more pronounced than in other brain areas and partially persisted for up to 3 months. Interestingly, the termination zones of entorhinal fibers in the dentate gyrus did not regain control levels within 3 months. We conclude from the data that functional recovery of denervated primary target areas does not occur within 3 months after entorhinal lesions and that altered functional activity may be found beyond the primary target areas predominantly during the acute recovery period after the lesion. The data suggest that sprouting fibers do not reestablish a fully functional neuronal network during the recovery period.

Correlation between retention behaviour and GC-FTIR data in the study of flavonoids

Trimethylsilyl derivatives of 10 different hydroxy- and methoxyhydroxyflavonoid compounds were studied by the GC-FTIR technique. Optimal deviation parameters were determined for the flavonoids studied. The correlation found between retention and gas-phase IR data can successfully be used in structural identification of compounds having very similar chromatographic behaviour. The shift of the carbonyl frequency gives information on the presence of substituting agents.

[Comparative study of antibiotic use at hospital departments in 7 Hungarian hospitals 1989-1991]

In their present work, authors, referring to their previous paper, wanted to compare the antibiotic consumption of the special medical fields in different hospitals. Computer database were utilised from different hospitals to obtain the necessary figures concerning antibiotic consumption. The amount of antibiotic consumption was expressed in Defined Daily Dose/1000 hospital day. The great differences found between hospitals in quality of antibiotic consumption related to the same subspeciality can be due to the different therapeutical approach in the respective departments. Quality of drug utilisation did not meet the expectations of the modern antibiotic therapy. Relatively low consumption was found in departments of ophthalmology, neurology, psychiatry and rehabilitation. Medium amount of antibiotic consumption was recorded in departments of internal medicine, general surgery, traumatology, obstetrics and gynecology, E. N. T. and dermatology. High antibiotic consumption was observed at the departments of urology, intensive care, infectology, pediatrics and pulmonology. Authors emphasise the importance of the education of the usage of antibiotics both at the medical universities and in postgraduate training as well.

[Comparative study of antibiotic consumption in Hungarian hospitals during 1989-1991]

The data of case histories of the year of 1989 of seven Hungarian hospitals and also the 1990 and 1991 data of two hospitals were collected and integrated in a database. Consumption of antibiotics were represented in DDD (Defined Daily Dose)/1000 hospital day. These data were compared with the data of the drugs delivered by the hospital pharmacy in one of the mentioned hospitals between 1989 and 1992. It was concluded that data based on case histories represent better the real antibiotic consumption than those of the hospital pharmacy. Reason of this phenomenon is the fact, that considerable amount of drug supply gets out of institutions. Great differences were observed between the seven hospitals in the total amount of antibiotic consumption and between the different antibiotic groups as well. Drugs most frequently used were tetracyclines, broad spectrum penicillins, sulfonamides and aminoglycosides. Consumption of penicillins was decreasing. Regarding new drugs only utilisation of quinolones was increasing. It was concluded, that structure of antibiotic selection did not follow the recommendations of the medical literature. The authors suggest that "antibiotic policy" should be introduced in Hungarian hospitals so as to imporve antibiotic utilisation.

Glutamate dehydrogenase in astrocytes of the rat dentate gyrus following lesion of the entorhinal cortex

Applying quantitative microscopic histochemistry, the activity of the mitochondrial glutamate dehydrogenase which is localized in astrocytes was determined in the molecular layer of the dentate gyrus of the rat hippocampus. This hippocampal region contains the important terminations of the glutamatergic perforant path. For comparison, determinations of the mitochondrial succinate dehydrogenase were performed, which is localized preferentially in terminals and dendrites. Two age groups of animals were examined: young adults (three months old) and aged subjects (24 months old). Both age groups were divided into controls, and animals killed three, 21 and 90 days following unilateral electrolytic lesion of the entorhinal cortex. The post-lesional shrinkage of the terminal field of the perforant path, ipsilateral to the lesion side, was determined and considered in the evaluation of enzymatic data. Statistic analysis revealed that ipsilateral to the lesion side there was a significant decrease of glutamate and succinate dehydrogenase activities in the terminal field of the perforant path three, 21 and 90 days following lesion. It is reasonable to assume that the decrease of succinate dehydrogenase activity (50-60%) was caused by the loss of mitochondria localized in degenerating terminals, whereas the decrease of glutamate dehydrogenase activity (20-30%) was related to the decrease of glutamatergic transmission following lesion. In the terminal field of the perforant path contralateral to the lesion side both significant increases and decreases of enzyme activities were measured following lesion. From these results it is concluded that the hippocampus contralateral to the lesion side cannot be considered as an appropriate intraindividual control. The comparison between young and aged animals showed no differences in the demonstration of glutamate dehydrogenase and only restricted differences in the activity level of succinate dehydrogenase post-lesion. Therefore, it is reasonable to assume that the post-lesional reactivity of the enzymes studied was very similar in both age groups.

[Specific enzyme diagnosis in mitochondrial myopathies and encephalomyopathies]

Mitochondrial enzyme activities (cytochrome c-oxidase = COX, carnitine acyl-transferase = CAT, citrate synthase = CS, lipoamide dehydrogenase = lipDH from the pyruvate-dehydrogenase complex, lactate dehydrogenase = LDH, and malate-dehydrogenase = MDH) were measured from progressive myopathy/encephalomyopathy. Cytochrome oxidase (COX) deficiency was detected from muscle or liver tissues, adult type of COX defectus had been diagnosed in 1 case and infantile type in further 6 cases. The 3 familial atactic children showed decreased activity of carnitine acetyl-transferase, too.

Determination of oxytetracycline and its decomposition products in Tetran vulnerary powder

A simple and fast HPLC method was developed for the determination of oxytetracycline and its decomposition products in pharmaceutical preparations. For this purpose an octadecyl modified silica stationary phase and a terner eluent containing aceto-nitrile-methanol-aqueous oxalic acid/EDTA solution was employed. Using this method, a stability study of oxytetracycline-containing powder was carried out. In this paper the analytical method and its performance data, the sample preparation and the obtained stability data are presented. The literature published on this topic is also shortly overviewed and discussed.

Acetylcholinesterase activity and post-lesional plasticity in the hippocampus of young and aged rats

Applying quantitative microscopic histochemistry, the activity of acetylcholinesterase was determined in the various layers of the rat hippocampus at three different levels along the rostrocaudal extent. Two age groups of animals were examined: young adults (two to three months old) and aged subjects (26 months old). Young adults were divided into controls, and animals killed eight and 35 days following bilateral ibotenate lesioning of the medial septum-diagonal band complex. Aged rats were divided into controls and animals 35 days post-lesion. Analysis of variance revealed that the mean acetylcholinesterase activities of the entire hippocampus of individuals were not significantly different between young and aged rats when averaged across controls and 35 days post-lesion. There was a significant decrease of acetylcholinesterase activity (-52%) in young adults eight days post-lesion as compared to controls, but a significant increase (+63%) took place until 35 days post-lesion as compared to eight days post-lesion. Significantly lower activities existed, however, in young (-22%) and aged rats (-18%) 35 days post-lesion as compared to controls. This decrease in mean activity was not age dependent. As acetylcholinesterase is considered to be a good cholinergic indicator in the hippocampus, the results suggest a homotypic collateral sprouting from spared cholinergic afferents following ibotenate lesion of the medial septum-diagonal band complex in young and aged rats. Based on the data obtained, it is reasonable to assume that there was no difference in the post-lesional plasticity of neuronal acetylcholinesterase between young adult and aged rats.

Chloroplast transformation in plants: polyethylene glycol (PEG) treatment of protoplasts is an alternative to biolistic delivery systems

Nicotiana plumbaginifolia protoplasts were directly transformed by PEG treatment with a cloned 16S rRNA gene isolated from a double antibiotic-resistant Nicotiana tabacum plastid mutant. Putative plastid transformants were selected in cell culture by their spectinomycin resistance and identified by their unselected streptomycin resistance. Alternatively, cell lines were selected in the presence of both antibiotics. The cell line (and its regenerated plants) selected solely for spectinomycin resistance demonstrated an extensive segregation of streptomycin resistance in subsequent tests, while the double-selected line showed stable resistance for both antibiotics. The resistance markers were inherited maternally. In the putative plastid transformants the origin of the resistance mutations was identified by the absence of an AatII site, missing in the donor N. tabacum plastid gene (spectinomycin resistance site) but present in that of wild-type N. plumbaginifolia, and a sequence analysis of the particular nucleotide changes in both resistance sites. Restriction enzyme analysis of total plastid DNA (ptDNA), and the recloning and full sequencing of the fragment introduced, investigated in one of the plastid transformants, showed no DNA rearrangements accompanied with the integration process. Sequence analysis indicated a targeted, homologous integration of the DNA fragment introduced but an unexpectedly complete homology of the parental ptDNA sequences in this region prevented the location of borders. Although the frequency of plastid transformant colonies (2 x 10(-5)) should still be improved, this method for stable chloroplast DNA transformation is comparable with or more efficient than the particle bombardment techniques.

Chloroplast transformation in plants: polyethylene glycol (PEG) treatment of protoplasts is an alternative to biolistic delivery systems

Nicotiana plumbaginifolia protoplasts were directly transformed by PEG treatment with a cloned 16S rRNA gene isolated from a double antibiotic-resistant Nicotiana tabacum plastid mutant. Putative plastid transformants were selected in cell culture by their spectinomycin resistance and identified by their unselected streptomycin resistance. Alternatively, cell lines were selected in the presence of both antibiotics. The cell line (and its regenerated plants) selected solely for spectinomycin resistance demonstrated an extensive segregation of streptomycin resistance in subsequent tests, while the double-selected line showed stable resistance for both antibiotics. The resistance markers were inherited maternally. In the putative plastid transformants the origin of the resistance mutations was identified by the absence of an AatII site, missing in the donor N. tabacum plastid gene (spectinomycin resistance site) but present in that of wild-type N. plumbaginifolia, and a sequence analysis of the particular nucleotide changes in both resistance sites. Restriction enzyme analysis of total plastid DNA (ptDNA), and the recloning and full sequencing of the fragment introduced, investigated in one of the plastid transformants, showed no DNA rearrangements accompanied with the integration process. Sequence analysis indicated a targeted, homologous integration of the DNA fragment introduced but an unexpectedly complete homology of the parental ptDNA sequences in this region prevented the location of borders. Although the frequency of plastid transformant colonies (2 x 10(-5)) should still be improved, this method for stable chloroplast DNA transformation is comparable with or more efficient than the particle bombardment techniques.

[Informative value of varying serum alpha fetoprotein levels in pregnant women based on a screening program in a Hungarian institute. What next?]

The authors evaluated the maternal serum alfa fetoprotein screening data of 3 years period. Out the neural tube defects they observed increased values at 20% of another congenital malformations. At the pregnant having abnormal serum alfa fetoprotein significantly accumulated the late-term abortion, stillbirth and preterm delivery. At the mothers of stillborns and abortions frequently noticed the different values. They direct attention to the fetal-living-danger importance, control functions of the abnormal level and after prospective data collection it may have new aspecific alarm role too. Accordingly the maternal serum alfa fetoprotein may consider like fetal blood sediment examination.

Effects of the 1,4-dihydropyridine-sensitive L-type calcium channel antagonist nimodipine and calcium channel activator Bay K 8644 on local cerebral glucose utilization in the rat

The quantitative [14C]-2-deoxy-D-glucose autoradiographic method was used to compare the acute effects of the Ca2+ channel antagonist nimodipine (10 mg/kg) and the Ca2+ channel activator Bay K 8644 (1.25 mg/kg) on local cerebral glucose utilization of rat brain after single, intraperitoneal application. Nimodipine reduced glucose metabolism significantly in 23 of the 49 brain regions evaluated. Bay K 8644 decreased the local cerebral glucose utilization to an even greater extent in all regions studied. The anatomic localization of those regions with the largest decrease of glucose utilization was almost identical for both drugs (globus pallidus, hippocampus, geniculate body, substantia nigra, and entorhinal cortex). No increase in glucose metabolism was measured in any of the brain areas evaluated.

Effects of 5-hydroxytryptamine1A-receptor agonists on hippocampal damage after transient forebrain ischemia in the Mongolian gerbil

The activation of 5-hydroxytryptamine receptors exerts an inhibitory influence on neuronal activity in a way similar to the activation gamma-amino-n-butyric acid and adenosine A1 receptors. Therefore, we hypothesized that 5-HT1A-receptor agonists might exert a neuroprotective effect. We tested the full agonists Bay R 1531 and 8-OH-DPAT and the partial agonists ipsapirone and gepirone in the model of transient global ischemia in the Mongolian gerbil. Ipsapirone protected 53% of pyramidal neurons (p less than 0.05) in the CA1 area of the hippocampus from ischemic damage at a dose of 3 mg/kg. Bay R 1531 showed a powerful neuroprotective effect with 100% preservation of neurons at a dose of 3 mg/kg (p less than 0.001) while gepirone and 8-OH-DPAT were ineffective. These findings suggest that 5-HT1A-receptor agonists might be effective tools for the therapy of cerebral ischemia. However, the varying results indicate that transient forebrain ischemia in the gerbil may not be the optimal model system to demonstrate clearly the neuroprotective activity of these compounds.

Effects of early onset of nimodipine treatment on microvascular integrity in the aging rat brain

We studied the effects of long-term treatment with 1,4-dihydropyridine nimodipine on age-related changes of the cerebral microvasculature in layers I, III, and V of the frontoparietal motor cortex of aged (30 months) male Wistar rats. Ultrastructural alterations of microvessels can either be attributed to degeneration or to deposition processes. Nimodipine application, irrespective of the time of onset, did not interfere with the degeneration of microvascular pericytes. However, nimodipine treatment from 24-30 months significantly reduced the amount of microvascular deposition products in cortical layers I and III, while an earlier onset (16 months) of the drug application resulted in a significant reduction in all motor cortex layers studied. This indicates a different susceptibility of microvessels in layer V of the frontoparietal motor cortex. These results show a beneficial effect of nimodipine on the integrity of cerebral microvasculature during aging and may provide a morphologic basis for the improved motor and cognitive performance in aged rats after chronic nimodipine application.