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Biomedical subjects

G Busch

Publications and source records attributed to G Busch.

At least 19 recordsLinked to original sources
PubMed2001

Forest ecosystems and the changing patterns of nitrogen input and acid deposition today and in the future based on a scenario.

A global assessment of the impact of the anthropogenic perturbation of the nitrogen and sulfur cycles on forest ecosystems is carried out for both the present-day [1980-1990] and for a projection into the future [2040-2050] under a scenario of economic development which represents a medium path of development according to expert guess [IPCC IS92a]. Results show that forest soils will receive considerably increasing loads of nitrogen and acid deposition and that deposition patterns are likely to change. The regions which are most prone to depletion of soils buffering capacity and supercritical nitrogen deposition are identified in the subtropical and tropical regions of South America and Southeast Asia apart from the well known 'hotspots' North-Eastern America and Central Europe. The forest areas likely to meet these two risks are still a minor fraction of the global forest ecosystems, though. But the bias between eutrophication and acidification will become greater and an enhanced growth triggered by the fertilizing effects of increasing nitrogen input cannot be balanced by the forest soils nutrient pools. Results show increasing loads into forest ecosystems which are likely to account for 46% higher acid loads and 36% higher nitrogen loads in relation to the 1980-1990 situation. Global background deposition of up to 5 kg N ha-1 a-1 will be exceeded at more than 25% of global forest ecosystems and at more than 50% of forest ecosystems on acid sensitive soils. More than 33% of forest ecosystems on acid sensitive soils will receive acid loads which exceeds their buffering capacity. About 25% of forest areas with exceeded acid loads will receive critical nitrogen loads.

Acid Rain↗
PubMed2001

Increased chromosomal imbalances in recurrent pituitary adenomas.

Eight pituitary adenomas (four gonadotroph cell adenomas, three prolactin cell adenomas, one null cell adenoma) and their respective recurrences in the same patients were studied by comparative genomic hybridization. Chromosomal imbalances were found in seven of eight patients affecting two of eight primary and seven of eight recurrent tumors. Overall, pituitary adenomas showed an average of 1.6 chromosomal imbalances per primary and 3.4 per recurrent tumor (P < 0.01). Prolactin cell adenomas showed an average of 4.3 chromosomal changes per primary and 6.3 per recurrent tumor, which were significantly more common than in gonadotroph cell adenomas (0 vs 1.7 changes; P < 0.05) and the null cell adenoma (0 vs 1.0 changes; P < 0.05). The most common changes were gains of 4q (in three of eight recurrences), 5q, and 13q (in two of eight recurrences each) as well as losses of chromosome 2 (in both primary and recurring tumors of two patients), 1p, 8q, 10, and 12q (in two of eight recurrences). Minimal common regions associated with recurrent adenomas were gains of 4q31.2-34 (three recurrences), 5q14-23 and 13q21-31 and losses of 12q24.3-qter (two recurrences each). The average MIB-1 proliferation indices were 1.2% for primary and 1.9% for recurrent adenomas (P < 0.005). Our findings suggest that acquisition of certain chromosomal imbalances is related to and may underlie adenoma recurrence.

Adult↗
PubMed1999

Stimulation of CD95 (Fas) blocks T lymphocyte calcium channels through sphingomyelinase and sphingolipids.

Calcium influx through store-operated calcium release-activated calcium channels (CRAC) is required for T cell activation, cytokine synthesis, and proliferation. The CD95 (Apo-1/Fas) receptor plays a role in self-tolerance and tumor immune escape, and it mediates apoptosis in activated T cells. In this paper we show that CD95-stimulation blocks CRAC and Ca(2+) influx in lymphocytes through the activation of acidic sphingomyelinase (ASM) and ceramide release. The block of Ca(2+) entry is lacking in CD95-defective lpr lymphocytes as well as in ASM-defective cells and can be restored by retransfection of ASM. C2 ceramide, C6 ceramide, and sphingosine block CRAC reversibly, whereas the inactive dihydroceramide has no effect. CD95-stimulation or the addition of ceramide prevents store-operated Ca(2+) influx, activation of the transcriptional regulator NFAT, and IL-2 synthesis. The block of CRAC by sphingomyelinase metabolites adds a function to the repertoire of the CD95 receptor inhibiting T cell activation signals.

Animals↗
PubMed1999

[Concentrating on weaknesses or compensating by strengths? Comparison of 2 strategies for remediation of children with comprehensive reading-spelling disorder].

Our study compares the efficiency and acceptance of two different methods of treating dyslexia in children. The first method addresses the most commonly encountered deficits in sequential processing. It relies primarly upon the "Kieler Lese-Rechtschreibaufbau". The second proceeds from the child's relative resources with regard to simultaneous processing as described by Kaufman. Training materials are those prescribed by Kaufman. Normally gifted primary school third-graders were trained in two groups (n = 13 and n = 12) and achieved a mean SIF score of SW = 101 on the K-ABC. As expected, the children scored significantly lower on the SED scale (SW = 95) than on the SGD scale (SW = 105). At the beginning of the respective training program their spelling ability fell 1.5 SD below the class mean. One year of regular weekly one-hour training according to the simultaneous processing method was significantly more successful than training in sequential processing, whereas girls improved significantly more than boys regardless of the method used. Acceptance of the methods did not vary. This result requires careful consideration and should be replicated in younger samples such as first- and second-graders in the early stages of learning to read and write, and/or in children whose dyslexia is more severe than that encountered in the current sample. It underscores that determination of an adequate method of remediation entails more than the mere identification of the underlying deficits.

Child↗
PubMed1995

Survival and death of prelymphomatous B-cells from N-myc/bcl-2 double transgenic mice correlates with the regulation of intracellular Ca2+ fluxes.

Coexpression of the proto-oncogenes c-myc and bcl-2 under the control of the immunoglobulin enhancer E mu provokes the rapid development of primitive lymphoid tumors in transgenic mice. In the present study we show that the myc family members N-myc and L-myc also cooperate with bcl-2 in oncogenesis and can provoke the development of more mature pre-B, B and T cell type lymphomas. The analysis of prelymphomatous B-cells from single E mu N-myc and bcl-2-Ig transgenic animals and from young, tumor free, double transgenic E mu N-myc/bcl-2-Ig mice revealed that E mu directed expression of N-myc leads to very rapid apoptosis after explantation and culturing compared to B-cells from normal mice. As expected, B-cells from bcl-2-Ig transgenics were protected to a certain degree from apoptosis. Strikingly however, B-cells from E mu N-myc/bcl-2-Ig double transgenic animals were found to be almost completely resistant towards a number of different apoptotic stimuli. Furthermore, after treatment with H2O2, which can trigger apoptosis, B-cells from E mu N-myc animals reach levels of intracellular free Ca2+ concentrations that are comparable to B-cells from normal mice, whereas B-cells from bcl-2-Ig or E mu N-myc/bcl-2-Ig double transgenic mice show no increase in intracellular Ca2+ concentrations after stimulation with H2O2. These findings suggest that the prevention of apoptosis conferred by bcl-2 correlates with the inhibition of intracellular Ca2+ fluxes whereas induction of apoptosis mediated by N-myc requires normal Ca2+ levels. We hypothesize therefore that the regulation of intracellular Ca2+ concentrations represent one important parameter in the oncogenic cooperation between bcl-2 and N-myc.

Animals↗
PubMed1995

Suppressing role of transforming growth factor-beta 1 on cathepsin activity in cultured kidney tubule cells.

Elevated expression and activity of transforming growth factor-beta 1 (TGF-beta 1) have been indicated in various renal diseases, implicating the potential involvement of this growth factor in the accumulation of extracellular matrix. To assess its potential role on protein turnover in tubule cells, we investigated in LLC-PK1 cells the effects of TGF-beta 1 on the activities of lysosomal cysteine proteinases cathepsins B, H, and L + B, which play a major role in the degradation of both cellular protein and extracellular matrix. The results show that 1-10 ng/ml TGF-beta 1 exerted inhibitory effects on cathepsin B and L + B activities, when applied to either the basolateral or apical membrane of these cells (basolateral side: B -23.2%, L + B -19.9%; apical side: B -28.2%, L + B -22.6%). Application of TGF-beta 1 to both sides enhanced suppression of the enzyme activities (B -37.8%, L + B -37.4%). This suppression of cathepsin activities was accompanied by a reduction of cellular protein degradation rate by 20.0% after 24 h and 51.7% after 48 h. Furthermore, TGF-beta 1 stimulated cellular protein synthesis by 50.0% after 48 h. The combined effects on protein turnover resulted in cellular hypertrophy: increases of both protein content and cell size after 48 h. Concerning the underlying mechanism, TGF-beta 1 did not induce a rise in intracellular Ca2+ concentration nor did Ca2+ channel blocker verapamil (10(-6) M) ameliorate the TGF-beta 1-induced inhibition of cathepsin activities. However, TGF-beta 1 raised the pH in lysosomes, which obviously impaired the acidic cysteine proteinases. In conclusion, the TGF-beta 1-induced cellular hypertrophy is caused by both enhanced protein synthesis and reduced protein breakdown. Suppression of cathepsin B and L + B activities mediated probably by an alkalinization in lysosomes is involved in the decreased protein degradation.

Animals↗
PubMed1993

Desmoplastic ganglioglioma: report of two non-infantile cases.

Two supratentorial desmoplastic gangliogliomas arising in a 15-year-old boy and a 25-year-old man are reported. Both tumors reached the brain surface and exhibited large cysts. They showed intense desmoplasia and tumor cells of astrocytic and ganglionic differentiation. In one case the ganglionic nature was only demonstrable by immunohistochemistry. Such neoplasms can no longer be regarded as exclusively infantile brain tumors.

Adolescent↗
PubMed1990

[The "vanishing twin"].

Three cases of a vanishing twin are reported. We observed twin pregnancies in three women, who had their ultrasound examination before the 10th week of pregnancy. Positive heartbeat was registered in both embryos. When a further sonographic examination took place at the 11th week, intrauterine death of one of the embryos was observed. All three pregnancies continued as singleton pregnancies to uneventful term deliveries. When the placentae and chorionic membranes were examined after delivery, small nodular pigmented areas were observed. Histological examination showed the remains of the embryo, who had vanished in the first trimester of pregnancy.

Embryo, Mammalian↗
PubMed1989

[Communication, compliance and perinatal risks of Turkish females in Tyrol].

Migrant workers from Turkey and their families make up 1% of the population of the Tyrol province in the west of Austria. They are the largest group of aliens. 152 Turkish women who were seen at our obstetrics department were investigated. Records of 121 women who had given birth to infants in the years 1984-86 were compared. 31 pregnant women were interviewed in their native language. More than 80% of all women studied went for routine check-ups four times or more during pregnancy. A number of conditions that would otherwise remain undetected are being diagnosed at routine pregnancy checks: tuberculosis, diabetes, genetic disease. Although patient compliance is good in this group, communication problems often put a successful outcome of the pregnancy at risk. Many women, who have been living in Austria for many years, are still unable to speak and understand German. Unqualified interpreters (husbands, children, relatives, hospital cleaning staff that is composed largely of Turks) often create problems by making up things the doctor would like to hear. The rate of cesarean sections is 11% in this group. Perinatal infant mortality rate is much higher than in the native Austrian population. The strict hygienic rules of Islam, the support and nurture supplied by the tightly-knit family structure of Turkish emigrants and a basically confident and trusting attitude towards doctors and nurses, if these can make themselves understood, should be recognised as positive factors and should be used to reduce perinatal risks in pregnant Turkish women.

Austria↗
PubMed1989

Selective isolation of individual cell surface proteins from tissue culture cells by a cleavable biotin label.

A method was developed to isolate cell surface proteins by a simple two-step procedure. Hepatocyte cell surface proteins were labeled by a cleavable biotin derivative in a covalent pulse reaction. Under the described conditions, NHS-SS-biotin proved to be an impermeant, cell surface-specific label which does not affect the impermeant, cell surface-specific label which does not affect the viability of rat hepatocytes. Biotinylated cell surface proteins could be selectively separated under non-denaturing conditions from non-biotinylated proteins and biotin-containing carboxylases by avidin affinity chromatography and sulfhydryl-mediated elution. Subsequent to alkylation of the eluted protein, individual cell surface proteins could be isolated by immunoprecipitation as shown for a selected Mr 120,000 glycoprotein gp120 of the hepatocyte plasma membrane. Using this technique, a transit time of gp120 from the endoplasmic reticulum to the cell surface of 2 h was determined. The results show that the combination of labeling with a cleavable biotin derivative, non-denaturing avidin affinity chromatography and immunoprecipitation is a useful method to isolate and study individual cell surface proteins.

Alkylation↗
PubMed1988

Aspects of signal transduction in stimulus exocytosis-coupling in Paramecium.

This paper deals with the detailed mechanisms of signal transduction that lead to exocytosis during regulative secretion induced by specific secretagogues in a eukaryotic cell, Paramecium tetraurelia. There are at least three cellular compartments involved in the process: I) the plasma membrane, which contains secretagogue receptors and other transmembrane proteins, II) the cytoplasms, particularly in the region between the cell and secretory vesicle membranes, where molecules may influence interactions of the membranes, and III) the secretory vesicle itself. The ciliated protozoan Paramecium tetraurelia is very well suited for the study of signal transduction events associated with exocytosis because this eukaryotic cell contains thousands of docked secretory vesicles (trichocysts) below the cell membrane which can be induced to release synchronously when triggered with secretagogue. This ensures a high signal-to-noise ratio for events associated with this process. Upon release the trichocyst membrane fuses with the cell membrane and the trichocyst content undergoes a Ca2+-dependent irreversible expansion. Secretory mutants are available which are blocked at different points in the signal transduction pathway. Aspects of the three components mentioned above that will be discussed here include a) the properties of the vesicle content, its pH, and its membrane; b) the role of phosphorylation/dephosphorylation of a cytosolic 63-kilodalton (kDa)Mr protein in membrane fusion; and c) how influx of extracellular Ca2+ required for exocytosis may take place via exocytic Ca2+ channels which may be associated with specific membrane microdomains (fusion rosettes).

Animals↗
PubMed1988

[Rehabilitation prognosis of aphasias of various etiologies with reference to clinical, neurolinguistic and computerized tomography findings].

To obtain further insights into the rehabilitation outlook in different baseline conditions, a comparison was made of data and treatment outcomes in 92 patients having aphasias of different etiology and disease duration. Rating as "improved" was contingent on significant changes in at least 2 subtests of the AAT (Aachener Aphasietest), which is a fairly stringent requirement. This criterion was met by some 35% of the patients overall, independent of their age; the percentage increased to 45% in case of treatment onset during the first year, while in later onset, significant improvement was achieved in 15% only. Aphasic syndromes secondary to hemorrhage, trauma, tumors, or infections, usually are less severe than the predominant classical syndromes, i.e. Global, Broca and Wernicke aphasia, caused by ischemic stroke. CT lesion size did not yield any definite information. Minor improvements below the required significance levels, and, above all, gains in communication performance, i.e. further consolidation, could be achieved by appropriate management even after the crucial initial year, which, however, does not imply any fundamental changes in the rehabilitation prognosis as such.

Aphasia↗
PubMed1987

Post-traumatic defects in computed tomography.

Long term CT-investigations of nearly 6000 brain-traumatized patients undergoing rehabilitative measures in the past ten years, showed pathologic findings in 85-90%: 40% showed abnormalities of the ventricular system; 60% traumatic tissue lesions; and 15% abnormalities of the brain surface. Kind and frequency of occurrence of the ventricular changes found by CT were in similar to those found by pneumencephalography. Traumatic inner-hydrocephalus permagnus, which occurred in about 0.25% of our patients, is considered with regard to its rehabilitative meaning. Most traumatic defects were found in the frontal lobe (36%) or in the temporal lobe (46%). Presence and etiology of traumatic infarctions were shown in CT images in 3.5% of all traumatic cases. 25% of these were situated in the posterior area: 25% in the basal ganglia; 15% in the midcerebral artery region, and 30% were typical borderline area infarctions. Because of the frequent differences between CT-findings and neurologic or neuropsychologic symptoms, CT-findings are to be judged only in conjunction with the clinical picture. They should never serve as the only guide for the exaluation of traumatic brain defects, prescribing therapy or predicting outcome.

Brain Concussion↗