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Biomedical subjects

T Becker

Publications and source records attributed to T Becker.

At least 37 records · Page 2Linked to original sources
PubMed1996

The polysialic acid modification of the neural cell adhesion molecule is involved in spatial learning and hippocampal long-term potentiation.

The alpha-2,8-linked polysialic acid (PSA) modification of the neural cell adhesion molecule (NCAM) modulates morphogenetic cell interactions. PSA is strongly expressed during neural development and generally down-regulated in the adult. However, it remains prominent in some areas of the brain, e.g., the hippocampus. We assayed the functional role(s) of PSA in synaptic plasticity in the hippocampus in two experimental paradigms by removing PSA with endo-neuraminidase NE (endo-N) an enzyme which specifically cleaves alpha-2,8-linked polysialic acid. (1) The acquisition and retention of spatial memory of rats in the Morris water maze, critically dependent on the hippocampus, was significantly impaired after a localized injection of endo-N into the hippocampus, whereas visual and motor capacities were unaffected. (2) Tetanic stimulation of the Schaffer collaterals in endo-N-treated hippocampal slices in vitro failed to elicit LTP and yielded only a short post-tetanic potentiation, but the response returned to control levels within 2 minutes, whereas basal synaptic activity and short-term potentiation were not affected. Our findings suggest that the carbohydrate epitope PSA plays an important role in synaptic plasticity.

Analysis of Variance↗
PubMed1996

[Ulcer healing through the elimination of Helicobacter pylori: is a week of therapy enough?].

AIM OF STUDY: To test whether one week's triple therapy with omeprazole and two antibiotics is enough to induce healing of a peptic (gastric and/or duodenal) ulcer. PATIENTS AND METHODS: 112 Patients (73 males, 39 females; median age 55 [18-88] years) proven by culture or histology to have an Helicobacter (H.) pylori infection and uncomplicated peptic (gastroduodenal) ulcer. For one week they received omeprazole (20 mg once or twice daily) plus two antibiotics (clarithromycin/metronidazole, clarithromycin/tetracycline, clarithromycin/amoxycillin or amoxycillin/metronidazole) to eradicate H. pylori. No further anti-ulcer treatment was given subsequently. Healing of the ulcer and H. pylori status were checked by the urease test, culture and histology (endoscopic biopsy) 4 weeks later. RESULTS: The 5-week ulcer healing rate was 94.6% (95% confidence interval: 89-98%). Persisting ulcers (n = 6) were associated with either treatment with aspirin or nonsteroidal antiinflammatory drugs (n = 3), persistent H. pylori infection (n = 2) or persistent H. pylori infection plus treatment with aspirin (n = 1). The ulcer healing rate was significantly higher in patients with eradicated infection than in those with posttherapy persistence of H. pylori (97.0 vs. 76.9%; P = 0.02). There were no significant differences after 5 weeks between patients with duodenal and those with gastric ulcer (97.4 vs. 89.3%). CONCLUSIONS: One-week effective eradication treatment is adequate to induce healing of H. pylori-positive peptic ulcers. Anti-ulcer treatment after eradication of H. pylori should be considered only if the patient is receiving treatment with ulcerogenic drugs or continues to have symptoms.

Adolescent↗
PubMed1996

Differential ontogenic pattern of metabotropic [3H]-L-glutamate receptors in normal and granule cell-deficient mouse cerebellum.

[3H]-L-glutamate binding site distribution corresponding to metabotropic receptors was studied by autoradiography during normal and altered cerebellar ontogeny in mice treated on postnatal days (PND) 5 and 6 with the antimitotic methylazoxymethanol (MAM). Quisqualate (QA)-induced and (2S,3S,4S)-alpha-(carboxycyclopropyl)-glycine (L-CCG-I)-induced [3H]-L-glutamate binding inhibition allowed us to distinguish between group I and group II metabotropic receptor binding sites. In control cerebellar cortex, the QA-sensitive binding site density increases during development, while the L-CCG-I-sensitive binding site density decreases. In the deep cerebellar nuclei (DCN), both populations of binding sites decrease during ontogeny. The antimitotic treatment induces: (1) a slight but significant increase in the QA-sensitive binding sites in the DCN at PND 10 and in the cerebellar cortex beginning from PND 20; (2) a retarded decrease in the L-CCG-I-sensitive metabotropic receptor binding site density. These differences could be due to a retarded cell maturation and/or an over-expression of some postsynaptic receptors in the adult cerebellum in response to the afference deficiency.

Amino Acids, Dicarboxylic↗
PubMed1996

One-week triple therapy with omeprazole, amoxycillin and either clarithromycin or metronidazole for cure of Helicobacter pylori infection.

AIM: The present study was designed to evaluate the efficacy and tolerability of 1-week triple therapy regimens for Helicobacter pylori. METHODS: In two consecutive series, 120 patients with proven H. pylori infection and peptic ulcer disease or functional dyspepsia were treated with either omeprazole 20 mg b.d., amoxycillin 1 g b.d. and clarithromycin 250 mg b.d. (OAC; n = 60) or with omeprazole 20 mg b.d., amoxycillin 1 g b.d. and metronidazole 400 mg b.d. over 1 week (OAM; n = 60). H. pylori infection was assessed by rapid urease test, culture and histology before and 4 weeks after cessation of the eradication therapy. RESULTS: H. pylori eradication succeeded in 53 out of 60 patients by omeprazole-amoxycillin-clarithromycin (OAC) (88%; 95% CI 77-95%) and in 47 out of 60 patients by omeprazole-amoxycillin-metronidazole (OAM) (78%; 95% CI 66-88%) (P = 0.22). Nine patients of each group available for follow-up reported adverse events (15.0 and 15.5%, respectively) without necessity of discontinuation of the study medications. Serious adverse events were not observed. CONCLUSIONS: Simple and convenient 1-week triple therapies consisting of omeprazole, amoxycillin and either clarithromycin or metronidazole are sufficiently effective in eradicating H. pylori infection.

Adolescent↗
PubMed1996

Trends in motor vehicle traffic fatalities among Hispanics, non-Hispanic whites and American Indians in New Mexico, 1958-1990.

OBJECTIVE: New Mexico has had the highest motor vehicle fatality rate in the nation for many years. Our objective was to examine ethnic differences and trends in motor vehicle fatality rates. DESIGN: Using death certificate data from the New Mexico Bureau of Vital Records and Health Statistics, we compiled age-adjusted motor vehicle-related mortality rates from 1958-1990 among the three major ethnic groups in New Mexico--Hispanics, white non-Hispanics and American Indians. RESULTS: Over the 33-year study period, American Indians of both sexes had two to three times higher mortality rates than white non-Hispanics. Hispanic males also had higher motor vehicle death rates than white non-Hispanic males. During the 1970s fatality rates peaked, with age-adjusted death rates of 233/100,000 for American Indian males, 74.7 for Hispanic males and 49.3 for white non-Hispanics for the period 1973-1977. Evaluation of successive 5-year birth cohorts showed highest mortality rates for ages 15-29 years for each ethnic group and both sexes, and a dramatic decline in most ethnic, sex and age-specific rates during the last eight years of the study period. CONCLUSION: Although the recent trends indicate favorable changes in motor vehicle fatality rates, our data highlight the need for ethnic and age-specific interventions to further reduce rates of motor vehicle-related mortality in this state.

Accidents, Traffic↗
PubMed1996

[Acute organic psychosis after malaria tropica].

Neuropsychiatric complications in the course of plasmodium falciparum infection are usually summarized as cerebral malaria. Heterogeneous clinical symptoms, different courses and inconstant parasitemia, however, suggest different pathogenic mechanisms. We report a case of an acute symptomatic psychosis occurring two weeks after successful therapy of a primary manifestation of plasmodium falciparum infection. The diagnosis of meningoencephalitis was based on lymphocytic pleocytosis of cerebrospinal fluid and hyperintense lesions in cranial magnetic resonance imaging. Due to the lack of plasmodium falciparum parasitemia and of serological evidence of viral infection a final diagnosis was not possible. Considering the pertinent literature, an immune-mediated complication of plasmodium falciparum infection (acute disseminated encephalomyelitis, ADEM) appears to be more probable than a direct viral or plasmodium CNS infection. We propose to reverse the term cerebral malaria for the cases with direct pathogenic influence of plasmodium falciparum, and to distinguish it from cases with possible immune-mediated pathogenesis.

Adult↗
PubMed1996

[Psychiatric sequelae of craniocerebral trauma--a review of the literature].

In a brief review psychiatric aspects of head-injured patients are discussed. The topic is put into a historical perspective. Examples of recent developments in head-trauma research are given. Differentiation between focal and diffuse brain injury is suggested to be of clinical relevance. Little is known as yet about the neuropsychologic and psychiatric sequelae of diffuse axonal injury to the brain.

Brain Concussion↗
PubMed1996

Cerebellar arachnoid cyst in a firesetter: the weight of organic lesions in arson.

A 52-year-old female patient was accused of arson; the patient had had an arachnoid cyst of the cerebellar vermis. Even after surgery, she showed marked instability of mood and pseudologia fantastica, but did not suffer from cognitive impairment. Possible associations of the presence of this cerebellar arachnoid cyst and behavioral disturbances are discussed.

Arachnoid Cysts↗
PubMed1995

Association of anophthalmia and esophageal atresia.

We report on a boy and a girl with bilateral anophthalmia and proximal esophageal atresia. In addition to vestigial optic nerves and chiasma, MRI studies showed other central nervous system abnormalities; one had ectopic tissue in the hypothalamic region, and the other hand generalized ventriculomegaly associated with atrophy. Two other cases, both males, have been reported with anophthalmia and esophageal atresia as their only malformations. These 4 cases are reviewed in light of recent advances in the understanding of ocular embryogenesis and of the midbrain as a development field. Concurrence of these defects appears to be non-random.

Anophthalmos↗
PubMed1995

Immunohistological localization of tenascin-C in the developing and regenerating retinotectal system of two amphibian species.

The expression pattern of the extracellular matrix molecule tenascin-C was investigated in the retinotectal system of the frog Discoglossus pictus and the salamander Pleurodeles waltl during development and optic nerve regeneration in the adult. In both species, the retina was devoid of tenascin-C immunoreactivity at all ages studied. During development, tenascin-C was distributed in a gradient in the optic nerve, with the highest immunoreactivity in the eye near part of the optic nerve. The myelin-associated glycoprotein was distributed in a gradient with opposite polarity. In Discoglossus, but not Pleurodeles, tenascin-C was detected in the anterior chiasm. In the tectum of both species, tenascin-C was observed in deep cellular and fiber layers but not in the layers receiving optic fibers or proliferative zones. The distribution patterns of tenascin-C were the same during development and in the adult, except for a disappearance of the molecule from the intraocular part of the optic nerve. After lesioning the optic nerve of adult animals, tenascin-C was strongly reexpressed in the intraocular part of the optic nerve but was only weakly upregulated in the distal optic nerve stump. In contrast, a chondroitin sulfate epitope was strongly upregulated in the distal optic nerve stump. These observations suggest that during development, tenascin-C serves as an attenuating barrier for myelinating cells in the optic nerve and contributes to the guidance of growing retinal ganglion cell axons. Due to its sustained expression in the adult, tenascin-C may have similar functions during regeneration of the lesioned adult retinotectal system.

Animals↗
PubMed1995

Reduced echogenicity of brainstem raphe specific to unipolar depression: a transcranial color-coded real-time sonography study.

Echogenicity of the brainstem raphe was assessed in patients with major depression, bipolar affective disorders, and schizophrenia and compared with healthy adults employing transcranial color-coded real-time sonography. Forty probands were enrolled in each group. A highly significant reduction in raphe echogenicity was detected only in patients suffering from major depression. Echogenicity of the raphe was independent of age or sex and did not correlate with severity of the depressive syndrome or patient state. These findings are suggestive of structural desintegration of the brainstem raphe in unipolar depression, an anatomical region assumed to be a biological focus in the pathogenesis of depressive syndromes.

Adult↗
PubMed1995

D- and L-lactate determination in dairy products: presentation of a fast automated analysis system.

A flow-injection system is presented, which is versatile, automated and has an integrated enzyme system. Its efficiency at determining D- and L-lactate separately in dairy products is compared with the officially used reference method (DIN 10335). By means of a mathematical elimination of matrix effects, the pretreatment steps can be clearly reduced. As a result of the immobilization of the enzymes, an appropriate automation software and an adaptation of the system developed to the given medium, the analysis could be performed within 5 min and was distinctly cheaper than alternative methods. The values determined in 15 different dairy products deviated from those of the reference method by 3% at a maximum.

Animals↗
PubMed1995

Some methodological issues in neuroradiological research in psychiatry.

An outline is given of some of the methodological issues discussed in neuroradiological research on psychiatric illness. Strengths and shortcomings of magnetic resonance imaging (MRI) in depicting and quantifying brain structures are described. Temporal lobe anatomy and pathology are easily accessible to MRI, whereas limits on anatomical delineation hamper approaches to frontal lobe study. White matter hyperintense lesions are sensitively depicted by MRI, but specificity is limited. Distinction of vascular and primary degenerative dementia is considerably improved by CT and MRI analysis. Computed tomography (CT) and MRI have enhanced the understanding of treatable organic psychiatric disorders, e.g., normal pressure hydrocephalus. Subcortical and white matter pathology has been replicated in CT and MRI studies of late-onset psychiatric disorders, clinical overlap with cerebrovascular disease or neurodegeneration may be of import. Transcranial sonography findings of brainstem structural change specific to unipolar depression may contribute to the understanding of affective psychoses. Magnetic resonance spectroscopy and functional MRI are likely to stimulate psychiatric research in the future.

Brain↗
PubMed1995

Disturbances of cerebrospinal fluid (CSF) circulation--neuropsychiatric symptoms and neuroradiological contribution.

The present study aimed at relating dementia, pseudo-neurasthenic and affective organic brain syndromes to underlying type of CSF flow disorder and to subsequent alteration of anatomy. T2*-weighted magnetic resonance imaging (MRI) in the midsagittal plane permitted an analysis of aqueductal CSF flow phenomena and hydrocephalus-induced elevation, thinning and dorsal impingement of the corpus callosum. Furthermore, the width of the third ventricle was measured on the transverse scout images. 72 patients with communicating hydrocephalus (increased aqueductal CSF pulsations) and 26 patients with aqueductal stenosis (absence of aqueductal flow phenomena) were compared with 22 controls. Dementia and affective disorders were distributed equally among both CSF flow subgroups whereas pseudo-neurasthenic syndromes were observed more frequently in non-communicating hydrocephalus (p < 0.03). Alzheimer-type and multiinfarct dementia syndromes were found more frequently in communicating hydrocephalus whereas non-classifiable dementia showed some predilection for non-communicating hydrocephalus. Callosal height, area and third ventricular width did not predict affective or pseudoneurasthenic disorder whereas third ventricular width (p < 0.01) and callosal area (p < 0.05) discriminated between demented and non-demented patients. Dorsal impingement of the corpus callosum by the falx was a non-specific finding.

Cerebral Aqueduct↗
PubMed1995

Larger topographical variance and decreased duration of brain electric microstates in depression.

The topographical configuration of the spontaneous brain electric fields is considered to contain relevant information about the pattern of the generating cortical electrochemical activation and the associated cognitive processes. Space oriented segmentation allows to break down the stream of the spontaneous EEG into brain electric microstates with stable configuration of the fields. It has been shown that the mean duration of the microstates was consistent with the duration of elementary steps of cognitive processes, and that different topographies of the microstates are associated with different cognitive modalities. Space-oriented segmentation was applied to the resting EEG of 22 depressive patients and of 22 controls. The topographical variance was larger, and the most prominent brain electrical microstates of the EEG epochs were significantly shorter in the depressive group than in controls. No differences were found for the shortest microstates. This result cannot be explained by group differences in the frequency domain of the EEG. No topographical differences were found between the microstates of depressives and those of controls. Based on previous results in healthy volunteers during spontaneous cognition and in schizophrenic patients, the findings indicate that formal aspects rather than the modalities of the stream of cognition are altered in depression. Automatic and schematic processing, and attentional deficits as described in depressive patients might account for the finding of less sustained brain electrical microstates.

Adult↗
PubMed1995

The corpus callosum in communicating and noncommunicating hydrocephalus.

To investigate morphological changes in the corpus callosum in hydrocephalus and to correlate them with clinical findings we studied sagittal T2*-weighted cine MR images of 163 patients with hydrocephalus. The height, length and cross-sectional area of the corpus callosum were measured and related to the type of cerebrospinal fluid flow anomaly and to clinical features, especially dementia. With expansion of the lateral ventricles the corpus callosum showed mainly elevation of its body and, to a lesser degree, increase in length. Upward bowing was more pronounced in noncommunicating than in communicating hydrocephalus. Dorsal impingement on the corpus callosum by the free edge of the falx correlated with the height of the corpus callosum. Cross-sectional area did not correlate with either height, length or impingement; it was, however, the strongest anatomical discriminator between demented and nondemented patients. The area of the corpus callosum was significantly smaller in patients with white matter disease. Our findings suggest that, due to its plasticity, the corpus callosum can to some degree resist distortion in hydrocephalus. Dementia, although statistically related to atrophy of the corpus callosum, is possibly more directly related to white matter disease.

Case-Control Studies↗
PubMed1995

Correlation of cerebral blood flow and MCA flow velocity measured in healthy volunteers during acetazolamide and CO2 stimulation.

The assessment of the cerebrovascular reserve capacity (RC) has become a widely used tool in the management of cerebrovascular disease. Discrepancies become obvious, however, if results obtained with different methods are compared. Aim of the present study, therefore, was to compare blood velocity and cerebral perfusion data in the same group of healthy test persons. In 32 volunteers regional cerebral blood flow (rCBF) was measured with the 133Xe-inhalation method. F1 as grey matter flow and the initial slope index (ISI) were computed. Simultaneously flow velocity in the middle cerebral artery (VMCA) was assessed by transcranial Doppler sonography (TCD). Measurements were performed in the resting state, during inhalation of 7% CO2 and after 1 g acetazolamide. Baseline VMCA was 62.38 +/- 16.1 cm/s, 90.84 +/- 23.85 cm/s during hypercapnia and 84.91 +/- 24.54 cm/s after acetazolamide. There was no significant change of baseline or stimulated values with age. F1 rose from baseline 76.25 +/- 12.48 ml/100 g/min to 103.90 +/- 14.6 ml/100 g/min in hypercapnia and to 98.4 +/- 14.9 ml/100 g/min after acetazolamide. The baseline F1 values and the response to CO2 decreased with age (p = 0.01) whereas for the acetazolamide reaction an age dependency could not be proven. ISI baseline values (41.5 +/- 6.1 ml/100 g/min) as well as those found after CO2 or acetazolamide decreased significantly with age. In hypercapnia changes of F1 and ISI were not too well related with changes of VMCA (F1: r = 0.599; ISI: r = 0.473), but better during acetazolamide exposure (F1: r4 = 0.715; ISI: r = 0.522). The age dependency of resting and stimulated values has to be considered when assessing the reserve capacity. There is a correlation between changes of the perfusion and flow parameters in healthy individuals which, however, may be worse in cerebrovascular disease.

Acetazolamide↗