Changes of pharmacological properties of (1S,3R)-ACPD-sensitive glutamate binding sites in developing mouse cerebellum

Autoradiography of [3H]glutamate binding to mouse cerebellar sections was used to study the distribution of (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid-((1S,3R)-ACPD) sensitive [3H]glutamate binding sites and the sensitivity of these sites to drugs preferentially acting on one or few types of the metabotropic receptor family. The inhibitory effect of (1S,3R)-ACPD on [3H]glutamate binding and its estimated inhibition constant showed the presence of a different global metabotropic receptor population according to the region considered. During ontogeny, the (1S,3R)-ACPD binding site density increased in the molecular layer (ML), in contrast it decreased in the internal granular layer (IGL) and the deep cerebellar nuclei (DCN). In addition, different sensitivities to (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG), (S)-4-carboxyphenylglycine (4-CPG), (2S,3S,4S)-alpha-(carboxycyclopropyl)glycine (L-CCG-I) and L-2-amino-4-phosphonobutyric acid (L-AP4) were demonstrated according to the region and the age. In the DCN, the high (1S,3R)-ACPD binding site density at PND 10 seems to be also sensitive to L-CCG-I but not to MCPG, 4-CPG or L-AP4. In the ML, the MCPG-, the 4-CPG- and the L-AP4-sensitive [3H]glutamate binding sites appeared during ontogeny and the L-CCG-I-sensitive [3H]glutamate binding sites were already present at PND 10. In the IGL, L-CCG-I-sensitive binding sites disappeared in contrast to the L-AP4-sensitive binding sites which appeared during development even if the total (1S,3R)-ACPD binding site density was relatively weak in the adults. These results all reflected the multiplicity of the receptor subtypes included in the cerebellar metabotropic component.

Echogenicity of the brainstem raphe in patients with major depression

A novel transcranial ultrasound technique was used to detect differences in the echogenicity and echotexture of the brainstem dorsal raphe nucleus in 20 patients with major depression compared with 20 age- and sex-matched healthy adults. Transcranial color-coded real-time sonography visualized the mesencephalic and pontine brainstem and its midline structure. The echogenicity of the raphe was classified in a four-point scale. Compared with healthy subjects, the depressed patients were characterized by a significant decrease in the echogenicity of the brainstem raphe. The echogenicity score was not correlated, however, with measures of psychopathology such as the Hamilton Rating Scale for Depression, the Clinical Global Impression Scale, the Global Assessment Scale, or the Depression Scale of von Zerssen. These preliminary findings suggest that the brainstem raphe may be involved in the etiopathogenesis of major depression. The echogenicity score should be further evaluated as a possible trait marker in different types of affective disorders.

Polysialic acid expression in the salamander retina is inducible by thyroxine

Polysialylation of the neural cell adhesion molecule (NCAM) in the retina of Pleurodeles waltl is up-regulated during metamorphosis. Incubation of larvae in thyroxine permanently induced polysialic acid expression in the retina in a concentration-dependent but age-independent manner within 3 days of incubation (3 x 10(-7) M). Retinoic acid had no effect. This suggests direct hormonal regulation of a post-translational modification of NCAM in the amphibian retina.

AgNOR counts in preneoplastic lesions of the bronchus

Silver staining of argyrophil nucleolar organizer regions (AgNORs) has become a valuable method to assess cell kinetics in paraffin sections and separate benign from malignant lesions. As a putative technique for the distinction between regenerative and preneoplastic alterations of the bronchial mucosa we employed the Ag-staining method, evaluating the number of dots/nucleus and shape of the dots. Dots/nucleus were counted by by standardized methods, and mean and standard deviation were calculated. Comparative investigations were performed in bioptically obtained specimens of normal bronchial epithelium (1.94 +/- 0.1 dots/nucleus, n = 12), basal cell hyperplasia (2.22 +/- 0.13 dots/nucleus, n = 15), goblet cell hyperplasia (2.38 +/- 0.16 dots/nucleus, n = 17), squamous cell metaplasia (2.58 +/- 0.17 dots/nucleus, n = 25), squamous cell metaplasia with mild and moderate dysplasia (2.50 +/- 0.5 dots/nucleus, n = 15), squamous cell metaplasia with severe dysplasia and carcinoma in situ (3.10 +/- 0.47 dots/nucleus, n = 17), micropapillomatosis (2.20 +/- 0.21 dots/nucleus, n = 13) and early squamous cell carcinoma of the bronchus (4.40 +/- 0.74, n = 13). In preneoplastic lesions a variability in form and size of the dots was found. Though showing an increase in the number of dots/nucleus coincidentally with the degree of proliferative activity, the AgNOR method cannot be considered as a statistically significant tool in the evaluation of regenerative and preneoplastic lesions in bioptically obtained specimens.

[Hyperintensive intramedullary lesions in psychiatric patients. Spatial distribution and psychopathologic symptoms]

In a sample of 130 patients who had undergone MRI (transverse T2-weighted SE sequence) patchy white matter lesions (WML) were documented according to number and spatial distribution in the brain. Ventricle-to-Brain Ratio (VBR) was determined. Configural frequency analysis led to delineation of four patient groups on the basis of WML location: 1. no WML (n = 35), 2. right frontal-temporal WML (n = 23), 3. bifrontal WML (n = 12), 4. WML in all/all but one brain region (n = 16). Psychopathological symptoms reported in the course of a maximum of 3 years were documented by chart review. In the 'pervasive WML' group psychopathological items characteristic of organic brain syndromes prevailed, mean VBR exceeded values in all other groups (ANOVA, p < 0.001). WML spatial distribution accounted for 10.2% of total psychopathological variance. Patient age, but not VBR, had a significant impact on symptom profile (MANCO-VA). When the 'pervasive WML' group was excluded, the finding of a significant effect of WML location on psychopathological symptom profiles was robust. Bifrontal WML were associated with thought incoherence, right frontal-temporal WML with affective symptoms. Findings support an impact of spatial distribution of unspecific WML on psychopathological symptoms in psychiatric patients.

Amphibian-specific regulation of polysialic acid and the neural cell adhesion molecule in development and regeneration of the retinotectal system of the salamander Pleurodeles waltl

Antibodies specific to the neural cell adhesion molecule (NCAM-total), the 180 x 10(3) M(r) component of NCAM (NCAM-180) and polysialic acid (PSA) were used in immunohistochemistry and Western blots to detect the spatiotemporal dynamics of these molecules in development and regeneration of the retinotectal system of Pleurodeles waltl. NCAM-total and NCAM-180 are continuously expressed in the retina, optic nerve, and tectum of the developing and adult salamander. This is also found for the 140 x 10(3) M(r) component of NCAM in Western blots of the retina. In the larval retina, PSA is present in the inner plexiform layer (IPL) and a few cells in all nuclear layers. At metamorphosis, PSA expression in the retina strongly increases in the layer of cone photoreceptor somata. Several cells in the inner nuclear layer and Müller cell processes also begin to express PSA. This pattern persists into adulthood. The optic nerve and the tectum are strongly PSA-immunoreactive throughout development. In the adult optic nerve and optic fiber pathway in the brain, PSA expression is selectively downregulated. In the crush-lesioned adult optic nerve, regenerating fibers are NCAM-180-positive but PSA-negative. This demonstrates a molecular difference between growing nerve fibers of Pleurodeles in development and in regeneration. PSA regulation is closely correlated with metamorphosis, thus suggesting that PSA expression may be under hormonal control. Some aspects of PSA and NCAM isoform expression patterns in the retinotectal system of salamanders differ considerably from that of other vertebrates. The sustained expression of NCAM isoforms in adult salamanders might be due to secondary simplification (paedomorphosis).

Hemodialysis for treatment of oxytetracycline-induced acute renal failure in a neonatal foal

Acute renal failure in a 4-day-old foal secondary to oxytetracycline toxicosis was treated by hemodialysis. Oxytetracycline had been administrered as treatment for forelimb flexor tendon contracture. Conservtive treatment with fluids, furosemide, and dopamine partially alleviated serum electrolyte concentration imbalances, but was ineffective in promoting diuresis or decreasing azotemia. Three hemodialysis treatments over 4 days were administered, after which the clinical appearance of the foal improved, and biochemical and electrolyte values returned to within reference ranges. The nephrotoxic potential of oxytetracycline should be considered prior to its administration. Hemodialysis may be a treatment option in management of acute renal failure in foals that are nonresponsive to conservative medical treatment.

Brain electrical activity in depression described by equivalent dipoles

The majority of neurophysiological investigations of waking EEG in depression have been relatively disappointing. Since the topographic distribution of brain electrical activity over the scalp in the frequency domain (FFT-power) varies considerably when choosing another site for the reference, it is not surprising that various investigators reported contradictory results. The aim of the present study was to investigate differences in brain electrical activity in a sample of depressed patients as compared to healthy subjects using a newly developed method called FFT approximation. As the major finding healthy subjects and depressed patients demonstrated significantly divergent patterns of localization between frequency bands in the anterior-posterior direction. The investigation suggests that a non-invasive neurophysiological methods gives results which are comparable to those obtained by other functional and structural imaging methods in depressive illness.

Distribution of NCAM-180 and polysialic acid in the developing tectum mesencephali of the frog Discoglossus pictus and the salamander Pleurodeles waltl

The 180 kDa component of the neural cell adhesion molecule (NCAM-180), total NCAM (NCAM-total) and the polysialic acid modification of NCAM (PSA) show similar temporal and spatial regulation in the developing tecta of Pleurodeles waltl (salamander) and Discoglossus pictus (frog). Whereas NCAM-total is found throughout the tectal tissue on neurons and glia, NCAM-180 is only found on non-proliferating neurons and in fiber layers. PSA is expressed by a subset of NCAM-180-positive cells. Western blots show that there is little polysialylated NCAM-140 in the developing amphibian tectum. Regions unstained for PSA and NCAM-180 correspond precisely to the growth zones of the tectum. NCAM-180 and PSA are not present in tecta of early larvae. Staining intensity is strongest at midlarval stages for both antigens. At metamorphosis, PSA is strongly downregulated, whereas NCAM-180 is downregulated in juvenile animals. Both antigens are still present in fiber layers of adult animals. In dissociated tissue culture of the frog tectum, NCAM-180 is not present on astrocytes, but on neuronal cells. Expression is enhanced at cell contact sites, suggesting that NCAM-180 is involved in cell contact stabilization. This study shows that general features of temporal and spatial regulation of NCAM isoforms and PSA are highly conserved in frog and salamander tecta, despite large differences in the rate of cell migration and the degree of lamination in these homologous brain regions.

An automatic dehydrogenase-based flow-injection system: application for the continuous determination of glucose and lactate in mammalian cell-cultures

A concept for the development of an automatic flow-injection analyzer with integrated dehydrogenase columns and its application in the control of industrial processes is presented. The system is based upon a kernel consisting of a nested-loop injection unit, pumps for the filling of the injection loops and the transport of buffer and values for switching on the one hand between sample and standard solutions and on the other hand between different enzyme columns. A Microsoft Windows 3.x application 'WIN-FIA' controls interactively the whole system and can be easily adapted to a specific solution of an analytical problem. As an example, the flow-injection system was used for the continuous determination of glucose and lactate, using glucose dehydrogenase (GDH) and lactate dehydrogenase (LDH) as indicator enzymes, in a mammalian cell-culture fermentation process. The resulting concentration values are in good agreement with those obtained by discontinuously taken standard spectrophotometric enzyme assays.

CNS control of a critical period for peripheral induction of central neurons in the leech

Most midbody ganglia in the central nervous system (CNS) of the leech Hirudo medicinalis contain about 400 neurons. However, those in the fifth and sixth midbody segments (ganglia M5 and M6) are specialized for reproductive functions, and each contain several hundred additional small neurons. These neurons arise late in embryogenesis as a result of an innervation-dependent inductive interaction between the male genitalia and M5 and M6 and are therefore known as peripherally induced central (PIC) neurons. The results of a series of ablation and transplantation experiments show that the PIC neurons are induced during a 1 to 2 day period about midway in embryogenesis (E15). The male genitalia are not necessary for induction before or after this period, and their presence for only one day may be sufficient for the induction to take place. Heterochronic transplantation of male genitalia shows that the critical period of interaction is independent of the age of the inducing tissues. Since the inductive signal is available from E10 to postembryonic stages, both the beginning and the end of the inductive period are determined by the CNS, not the periphery.

Protein-protein interaction studied by site-directed mutagenesis. Characterization of the annexin II-binding site on p11, a member of the S100 protein family

p11, a member of the S100 protein family, forms a stable heterotetrameric complex with annexin II. The p11-binding site of annexin II resides in the N-terminal 14 residues, which form an amphiphatic alpha-helix with the hydrophobic face representing the contact site for p11 (Johnsson, N., Marriott, G., and Weber, K. (1988) EMBO J. 7, 2435-2442). We show that a corresponding peptide can be used to purify recombinant p11 by affinity chromatography. To map the annexin II-binding site on p11, we have produced progressively truncated p11 derivatives by site-directed mutagenesis. Our analysis reveals that a highly hydrophobic region between residues 85 and 91 is indispensable for annexin II-binding. It is located in the C-terminal extension, following the second distorted EF-hand. Using a series of single amino acid replacements, we have identified individual hydrophobic residues, which seem to represent contact points for annexin II. Most notably, substitution of tyrosine 85 or phenylalanine 86 by alanine drastically reduces the affinity of p11 for annexin II, whereas replacement of these residues by tryptophan has no or only a marginal effect. Thus, hydrophobic side chains on both annexin II and p11 are involved in complex formation.

S100P, a novel Ca(2+)-binding protein from human placenta. cDNA cloning, recombinant protein expression and Ca2+ binding properties

A novel member of the S100 protein family, present in human placenta, has been characterized by protein sequencing, cDNA cloning, and analysis of Ca(2+)-binding properties. Since the placenta protein of 95 amino acid residues shares about 50% sequence identity with the brain S100 proteins alpha and beta, we proposed the name S100P. The cDNA was expressed in Escherichia coli and recombinant S100P was purified in high yield. S100P is a homodimer and has two functional EF hands/polypeptide chain. The low-affinity site (Kd = 800 microM), which, in analogy to S100 beta, seems to involve the N-terminal EF hand, can be followed by the Ca(2+)-dependent decrease in tyrosine fluorescence. The high-affinity site, provided by the C-terminal EF hand, influences the reactivity of the sole cysteine which is located in the C-terminal extension (Cys85). Binding to the high-affinity site (Kd = 1.6 microM) can be monitored by fluorescence spectroscopy of S100P labelled at Cys85 with 6-proprionyl-2-dimethylaminonaphthalene (Prodan). The Prodan fluorescence shows a Ca(2+)-dependent red shift of the maximum emission wavelength from 485 nm to 502 nm, which is accompanied by an approximately twofold loss in integrated fluorescence intensity. This indicates that Cys85 becomes more exposed to the solvent in Ca(2+)-bound S100P, making this region of the molecule, the so-called C-terminal extension, an ideal candidate for a putative Ca(2+)-dependent interaction with a cellular target. In p11, a different member of the S100 family, the C-terminal extension which contains a corresponding cysteine (Cys82 in p11), is involved in a Ca(2+)-independent complex formation with the protein ligand annexin II. The combined results support the hypothesis that S100 proteins interact in general with their targets after a Ca(2+)-dependent conformational change which involves hydrophobic residues of the C-terminal extension.

MRI white matter hyperintensity in neuroleptic malignant syndrome (NMS)--a clue to pathogenesis?

The case of a young female patient with neuroleptic malignant syndrome (NMS) and extended MRI white matter hyperintensity in the left parietal and both occipital lobes is reported. MRI lesions resembled findings in hypertensive encephalopathy, they were not readily compatible with CNS vasculitis. Venous sinus thrombosis could be ruled out. Vascular encephalopathy with transient white matter edema and a small residual left parietal lesion is suggested. Neurochemical implications are discussed with particular reference to a possible involvement of excitatory amino acids in NMS pathogenesis.

Post partum blues: depressive disease or pseudoneurasthenic syndrome

Depressive mood disorders following childbirth can be quantified with self-rating and observer-rating scales. During two months, in the period from November 1989 to March 1990, women admitted to the obstetric unit of the University of Würzburg were examined on days 3 and 5 post-partum with the Hamilton Psychiatric Rating Scale for Depression, the Montgomery-Asberg-Depression-Rating-Scale and the Befindlichkeits-Scale by von Zerssen. Results reveal that during the early puerperium, scores on these scales rarely reach the same severity as in major depressive disorder. The clinical picture is no different from emotional-hyperaesthetic hyposthenia following other kinds of physical illness such as endocrine disorders.

Neurological long-term follow-up in left atrial myxoma: are late complications frequent or rare?

Neurological manifestations were analysed in 13 patients with left atrial myxoma confirmed by histological study. In this group, 6 patients had neurological complaints at initial presentation, 5 had cardiac symptoms, and 4 patients presented with signs of systemic disease. CT was performed in 10 and MRI in 7 patients. There were signs of ischaemic or haemorrhagic infarction (6 of 12) and one lesion suggestive of myxoma metastasis; other findings mainly comprised non-specific white matter lesions revealed by MRI. Neurological follow-up 0.5-8 years after tumour resection revealed no delayed neurological complications, follow-up CT and MRI findings were not suggestive of lesions acquired after operation. It is suggested that this rare condition of cardiac myxoma should be suspected in young patients with CNS symptoms or signs lacking cerebrovascular or cardiovascular risk factors and should be included in the differential diagnosis of vasculitis. With timely diagnosis and resection of the cardiac tumour the long-term prognosis can be considered improved.

Nimodipine and flunarizine in alcohol withdrawal: an open study

An open pilot study of the calcium antagonists nimodipine (240 mg/die p.o.) and flunarizine (20 mg/die p.o.) as a treatment in alcohol withdrawal was conducted. Two of the eight patients who received nimodipine and one of the eight patients who received flunarizine developed a confusional state preceded, in one of the patients with nimodipine and in the patient with flunarizine, by a generalized tonic-clonic seizure. The patients receiving flunarizine seemed to recover faster from the alcohol withdrawal syndrome than the patients receiving nimodipine. Given the limited capability of both drugs to prevent severe withdrawal symptoms at the doses tested, double-blind studies with these drugs, possibly with higher doses and i.v. administration should follow an add-on design.