julilili42/papers huggingface dataset:
Opposite hemispheric lateralization effects during speaking and singing at motor cortex, insula and cerebellum
2000-06-01

Aside from spoken language, singing represents a second mode of acoustic (auditory-vocal) communication in humans. As a new aspect of brain lateralization, functional magnetic resonance imaging (fMRI) revealed two complementary cerebral networks subserving singing and speaking. Reproduction of a non-lyrical tune elicited activation predominantly in the right motor cortex, the right anterior insula, and the left cerebellum whereas the opposite response pattern emerged during a speech task. In contrast to the hemodynamic responses within motor cortex and cerebellum, activation of the intrasylvian cortex turned out to be bound to overt task performance. These findings corroborate the assumption that the left insula supports the coordination of speech articulation. Similarly, the right insula might mediate temporo-spatial control of vocal tract musculature during overt singing. Both speech and melody production require the integration of sound structure or tonal patterns, respectively, with a speaker's emotions and attitudes. Considering the widespread interconnections with premotor cortex and limbic structures, the insula is especially suited for this task.
A new member of acid-sensing ion channels from pituitary gland
2000-06-01

Acid-sensing ion channels (ASICs) constitute a branch of the super-gene family of amiloride-sensitive sodium channels. So far five different ASICs have been cloned from mammalian tissues. They are activated by a drop of extracellular pH but differ with respect to effective agonist concentration, desensitization and mRNA expression pattern. Here we report cloning of ASIC4, a new protein showing about 45% identity to other ASICs. ASIC4 is 97% identical between rat and human and shows strongest expression in pituitary gland. Moreover, we detected expression throughout the brain, in spinal cord, and inner ear. ASIC4 cannot be activated by a drop of extracellular pH in Xenopus oocytes, suggesting association with other subunits or activation by a ligand different from protons. Our results suggest a role for ASICs also in endocrine glands.
Hypersensitivity of an Arabidopsis Sugar Signaling Mutant toward Exogenous Proline Application
2000-06-01

Abstract In transgenic Arabidopsis a patatin class I promoter from potato is regulated by sugars and proline (Pro), thus integrating signals derived from carbon and nitrogen metabolism. In both cases a signaling cascade involving protein phosphatases is involved in induction. Other endogenous genes are also regulated by both Pro and carbohydrates. Chalcone synthase (CHS) gene expression is induced by both, whereas the Pro biosynthetic Δ1-pyrroline-5-carboxylate synthetase (P5CS) is induced by high Suc concentrations but repressed by Pro, and Pro dehydrogenase (ProDH) is inversely regulated. The mutantrsr1-1, impaired in sugar dependent induction of the patatin promoter, is hypersensitive to low levels of external Pro and develops autofluorescence and necroses. Toxicity of Pro can be ameliorated by salt stress and exogenously supplied metabolizable carbohydrates. The rsr1-1 mutant shows a reduced response regarding sugar induction of CHS andP5CS expression. ProDH expression is de-repressed in the mutant but still down-regulated by sugar. Pro toxicity seems to be mediated by the degradation intermediate Δ1-pyrroline-5-carboxylate. Induction of the patatin promoter by carbohydrates and Pro, together with the Pro hypersensitivity of the mutant rsr1-1, demonstrate a new link between carbon/nitrogen and stress responses.
Ultrasound examination of regional lymph nodes significantly improves early detection of locoregional metastases during the follow-up of patients with cutaneous melanoma
2000-06-01

For early diagnosis of in-transit and regional lymph node metastases in cutaneous melanoma, ultrasound scanning is distinctly superior to clinical examination. Controlled follow-up studies are proposed to examine the possible beneficial effects on survival time resulting from the ultrasound examinations of the lymphatic drainage area(s) and regional lymph nodes.
A binary spelling interface with random errors
2000-06-01

An algorithm for design of a spelling interface based on a modified Huffman's algorithm is presented. This algorithm builds a full binary tree that allows to maximize an average probability to reach a leaf where a required character is located when a choice at each node is made with possible errors. A means to correct errors (a delete-function) and an optimization method to build this delete-function into the binary tree are also discussed. Such a spelling interface could be successfully applied to any menu-orientated alternative communication system when a user (typically, a patient with devastating neuromuscular handicap) is not able to express an intended single binary response, either through motor responses or by using of brain-computer interfaces, with an absolute reliability.
Molecular Remodeling of Kv4.3 Potassium Channels in Human Atrial Fibrillation
2000-06-01

Repolarizing Potassium Currents in Atrial Fibrillation, introduction: Atrial fibrillation (AF) is associated with important alterations in cardiac ion channels that cause shortening and impaired rate adaptation of atrial repolarization. The mechanisms underlying potassium current remodeling in human AF are not clear. We investigated the effects of AF on the gene expression of the Kv4.3, Kv1.4, and Kv1.5 potassium channel subunits and correlated the findings with the transient outward (I 10 ) and the sustained outward (I sus or I kur ) potassium current. Methods and Results: Semiquantitative reverse transcription‐polymerase chain reaction was used to evaluate mRNA expression, and ion currents were studied with the patch clamp technique in right atrial appendages from patients in AF and compared with those from patients in stable sinus rhythm (SR). The presence of AF was associated with a 61% reduction in Kv4.3 mRNA expression (P &lt; 0.001 vs SR), which was paralleled by a reduction in I to current densities in this group of patients (i.e., at ± 50 mV: 7.44 ± 0.76 pA/pF in SR and 1.24 ± 0.28 pA/pF in AF; P &lt; 0.001 vs SR). mRNA levels of Kv 1.4 were identical in the two groups. AF did not affect either the gene expression of Kv 1.5 or the current densities of I sus . Conclusion: Chronic AF in humans reduces I to by transcriptional down‐regulation of the Kv4.3 potassium channel. Altered gene expression is an important component of the electrical remodeling process and may contribute to repolarization abnormalities in AF.
The Macrocyclic Peptide Antibiotic Micrococcin P1Is Secreted by the Food-Borne BacteriumStaphylococcus equorumWS 2733 and InhibitsListeria monocytogeneson Soft Cheese
2000-06-01

ABSTRACT Staphylococcus equorum WS 2733 was found to produce a substance exhibiting a bacteriostatic effect on a variety of gram-positive bacteria. The metabolite was purified to homogeneity by ammonium sulfate precipitation and semipreparative reversed-phase high-performance liquid chromatography. Electrospray mass spectrometry confirmed the high purity of the compound and revealed a molecular mass of 1,143 Da. By two-dimensional nuclear magnetic resonance spectroscopy the substance was identified as micrococcin P 1 which is a macrocyclic peptide antibiotic that has not yet been reported for the genus Staphylococcus . A total of 95 out of 95 Listeria strains and 130 out of 135 other gram-positive bacteria were inhibited by this substance, while none of 37 gram-negative bacteria were affected. The antilisterial potential of this food-grade strain as a protective starter culture was evaluated by its in situ application in cheese-ripening experiments under laboratory conditions. A remarkable growth reduction of Listeria monocytogenes could be achieved compared to control cheese ripened with a nonbacteriocinogenic type strain of Staphylococcus equorum . In order to prove that inhibition was due to micrococcin P 1 , a micrococcin-deficient mutant was constructed which did not inhibit L. monocytogenes in cheese-ripening experiments.
Effect of topical application of Hypericum perforatum extract (St. John's wort) on skin sensitivity to solar simulated radiation
2000-06-01

St. John's wort (Hypericum perforatum) is a tradional folk remedy that is used for the topical treatment of superficial wounds, scars and burns. A characteristic metabolite of St. John's wort is the photodynamic active plant pigment hypericin. It is known that hypericin may cause a severe photodermatitis called hypericism when higher amounts of St. John's wort are ingested orally. To date, no reports on the photosensitizing capacity of topical application of St. John's wort are available. Here, we investigated the effects of Hypericum oil (hypericin 110 microg/mL) and Hypericum ointment (hypericin 30 microg/mL) on skin sensitivity to solar simulated radiation. Sixteen volunteers of the skin types II and III were tested on their volar forearms with solar simulated radiation for photosensitizing effects of Hypericum oil (n=8) and Hypericum ointment (n=8). The minimal erythema dose (MED) was determined by visual assessment, and skin erythema was evaluated photometrically. With the visual erythema score, no change of the MED could be detected after application of either Hypericum oil or Hypericum ointment (P>0.05). With the more sensitive photometric measurement, an increase of the erythema-index after treatment with the Hypericum oil could be detected (P< or =0.01). The results do not provide evidence for a severe phototoxic potential of Hypericum oil and Hypericum ointment, detectable by the clinically relevant visual erythema score. However, the trend towards increased photosensitivity detected with the more sensitive photometric measurement could become relevant in fair-skinned individuals, in diseased skin or after extended solar irradiation.
Insulin signaling and action in cultured skeletal muscle cells from lean healthy humans with high and low insulin sensitivity.
2000-06-01

The aim of these studies was to investigate whether insulin resistance is primary to skeletal muscle. Myoblasts were isolated from muscle biopsies of 8 lean insulin-resistant and 8 carefully matched insulin-sensitive subjects (metabolic clearance rates as determined by euglycemic-hyperinsulinemic clamp: 5.8 +/- 0.5 vs. 12.3 +/- 1.7 ml x kg(-1) x min(-1), respectively; P &amp;lt; or = 0.05) and differentiated to myotubes. In these cells, insulin stimulation of glucose uptake, glycogen synthesis, insulin receptor (IR) kinase activity, and insulin receptor substrate 1-associated phosphatidylinositol 3-kinase (PI 3-kinase) activity were measured. Furthermore, insulin activation of protein kinase B (PKB) was compared with immunoblotting of serine residues at position 473. Basal glucose uptake (1.05 +/- 0.07 vs. 0.95 +/- 0.07 relative units, respectively; P = 0.49) and basal glycogen synthesis (1.02 +/- 0.11 vs. 0.98 +/- 0.11 relative units, respectively; P = 0.89) were not different in myotubes from insulin-resistant and insulin-sensitive subjects. Maximal insulin responsiveness of glucose uptake (1.35 +/- 0.03-fold vs. 1.41 +/- 0.05-fold over basal for insulin-resistant and insulin-sensitive subjects, respectively; P = 0.43) and glycogen synthesis (2.00 +/- 0.13-fold vs. 2.10 +/- 0.16-fold over basal for insulin-resistant and insulin-sensitive subjects, respectively; P = 0.66) were also not different. Insulin stimulation (1 nmol/l) of IR kinase and PI 3-kinase were maximal within 5 min (approximately 8- and 5-fold over basal, respectively), and insulin activation of PKB was maximal within 15 min (approximately 3.5-fold over basal). These time kinetics were not significantly different between groups. In summary, our data show that insulin action and signaling in cultured skeletal muscle cells from normoglycemic lean insulin-resistant subjects is not different from that in cells from insulin-sensitive subjects. This suggests an important role of environmental factors in the development of insulin resistance in skeletal muscle.
Experimental investigation of the effect of high-pH solutions on the Opalinus Shale and the Hammerschmiede Smectite
2000-06-01

Abstract The alteration and transformation behaviour of the Tertiary Hammerschmiede Smectite and the Jurassic Opalinus Shale in an alkaline solution was studied in column experiments. The Hammerschmiede Smectite is proposed as potential backfill material and the Opalinus Shale as host rock for the Swiss low-level nuclear waste storage site. Over a period of 18 months, the evolution of permeability, pH and solution concentrations were measured. After the experiment, the columns were cut into pieces to study the mineralogical and the chemical evolution of the clays. X-ray diffraction (XRD) revealed no significant appearance or disappearance of diffraction peaks at the end of the experiments. The scanning electron micrographs of the clays revealed that both clays exhibited a precipitation zone, which extends from 0 to 2 cm below the infiltration surface. Both clays showed significant differences in the evolution of pH and hydraulic conductivity. The solution front crossed the Opalinus Shale column entirely after only 11 weeks and the initial values for K + and Na + were conserved in the solution. For both clays, the salt concentrations in the percolating fluids mirror the evolution of pH.
Prolyl isomerases in a minimal cell
2000-06-01

Peptidyl‐prolyl cis / trans isomerases (PPIases) catalyze the isomerization of prolyl peptide bonds. Distinct families of this class of enzymes are involved in protein folding in vitro , whereas their significance in free living organisms is not known. Previously, we inspected the smallest known genome of a self‐replicating organism and found that Mycoplasma genitalium is devoid of all known PPIases except the trigger factor. Despite the extensive sequence information becoming available, most genes remain hypothetical and enzyme activities in many species have not been assigned to an open reading frame. Therefore, we studied the PPIase activity in crude extracts of M. genitalium . We showed that this is solely attributed to a single enzyme activity, the trigger factor. Characterization of this enzyme revealed that its PPIase activity resides in a central 12‐kDa domain. Only the complete trigger factor is able to cis / trans isomerize extended peptide substrates, while the PPIase domain alone can not. The N‐ and the C‐terminal domains of the trigger factor seem to function in binding of proteins as substrates, as demonstrated by protein refolding experiments, in which the complete trigger factor catalyzed protein refolding towards a model protein 500‐fold more efficiently than the isolated central PPIase domain. Protein modeling studies suggest that the PPIase domain can fold in a similar way as the PPIase domain of FK506 binding proteins (FKBPs), one class of PPIases, despite only very limited sequence homology. Differences at the active site explain why this enzyme is not inhibited by FK506 in contrast with FKBPs. Trigger factor expressed in Escherichia coli confirms its additional chaperone functions, as shown by its association with chaperones GroEL and GroES after induction of misfolding. In contrast, the isolated PPIase‐domain lacks any association with chaperones from E. coli . In summary, trigger factor of M. genitalium is the single folding isomerase of this organism, which harbors an enzymatically active PPIase domain with structural homology to FKBPs. Its additional domains confer its ability to be an efficient catalyst of protein folding. The protein folding machinery is conserved and shows a dual function as a chaperone and a prolyl isomerase.
Cranial anatomy and palaeobiology of the Miocene marsupial Hondalagus altiplanensis and a phylogeny of argyrolagids
2000-06-01

New cranial material of Hondalagus altiplanensis , from the middle Miocene of southern Bolivia, allows a rediagnosis of the genus and an assessment of its palaeobiology and phylogenetic relationships with other argyrolagid marsupials. The new specimens demonstrate several derived (synapomorphic) cranial features shared by Hondalagus Argyrolagus : a globular braincase, ventrally directed occipital condyles, a broad zygomatic arch, and a short, deep dentary with a flat and long coronoid notch. Hondalagus had powerful masticatory muscles and its cementum‐encased hypselodont cheek teeth suggests it had a very abrasive diet. The deep fossae on the lateral aspect of the skull of argyrolagids, interpreted by Simpson as large, laterally‐facing orbits, are actually sharply margined temporal fossae. Hondalagus has a very large carotid foramen medially situated within the suture of the basisphenoid and basioccipital. A phylogenetic analysis of five argyrolagid genera was conducted using 32 characters (16 cranial, 16 dental) and a didelphid and a caenolestid as outgroups. Hondalagus‐Argyrolagus‐Microtragulus form a monophyletic group with an undescribed gen. et sp. nov. (MACN‐Ch‐1305) from the lower Miocene (Colhuehuapian) of Argentina as its sister taxon. Proargyrolagus appears as sister group to the other taxa of argyrolagids.
Ticks and tick-borne diseases: a vector-host interaction model for the brown ear tick (Rhipicephalus appendiculatus)
2000-06-01

An analytical model is derived for the interaction of the brown ear tick ( Rhipicephalus appendiculatus) with its hosts. Such models are rare due to the complexity and lack of information on the entire stages of ticks life cycles. Most models are simulations rather than analytical. The vector is categorized into a discrete number of compartments according to its life cycle. The starting model in this article consists of a system of differential equations with constant coefficients. A general model on a stage structured population with unlimited host density is developed. From the characteristic polynomial of the system a sensitivity analysis for the population parameters is carried out in detail. The model is then improved by incorporating host abundance and availability. This is done on the basis of a demand-driven and ratio-dependent functional response model. The improved model adequately represents the dynamics of a stage-structured vector population under conditions of varying host density. The model allows the qualitative evaluation of several management strategies and is expected to guide future research work.
Deamidation as a widespread phenomenon in two-dimensional polyacrylamide gel electrophoresis of human blood plasma proteins
2000-06-01

The human plasma protein patterns obtained by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is a good model system for post-translational modifications because of the existence of several "ladders" of protein spots [Anderson, N. L., Anderson, N. G., Electrophoresis 1991, 12, 883-906], so-called "trains" of spots. Our investigation of several proteins, amongst others beta2-microglobulin and the haptoglobin chains, found the differences in isoelectric points (p/) to be due to deamidation of asparagines. After enzymatic cleavage with endopeptidases in the 2-D polyacrylamide gel, the asparagine and deamidated asparagine containing peptides were separated and quantified by reversed-phase HPLC. In order to separate these peptides, a neutral pH system was established and, as a result, the differences in hydrophobicity of asparagine-containing and deamidated asparagine-containing peptides increased. But how do deamidated asparagines contribute to the observed spot pattern? One spot in the 2-D gel consists of a mixture of protein species with the same number of deamidated asparagines but on different sequence position sites. The difference between the spots in the "ladder" is a growing number of negative charges introduced in the protein by an increasing number of deamidated asparagines. As a consequence, the mass difference between two spots is exactly 1 Da, which is shown in this paper for intact protein masses and the corresponding deamidated peptides.
The relative risk of second nongerminal malignancies in patients with extragonadal germ cell tumors
2000-06-01

This analysis excludes an increased biologic risk of developing second solid malignancies in patients with extragonadal GCT except for the previously reported association between primary mediastinal nonseminoma and hematologic disorders. The overall risk of developing second malignancies in extragonadal GCT patients appears to be comparable to that in patients with primary testicular carcinoma. The incremental occurrence of skin malignancies in patients treated with chemotherapy should be investigated further.
Differential Cellular Accumulation of Transforming Growth Factor–β1, –β2, and –β3 in Brains of Patients Who Died with Cerebral Malaria
2000-06-01

In cerebral malaria (CM), pathologic cytokine expression patterns are thought to contribute to disruption of the blood-brain barrier, inflammation, and astrocytic scar formation. Expression of transforming growth factor (TGF)-beta1, -beta2, and -beta3 was analyzed in the brains of 7 patients who died with CM and in 8 control patients. In the brains of patients with CM, there were significantly (P=.0003) more TGF-beta1-immunoreactive astrocytes adjacent to brain vessels with deposition of malarial pigment, significantly (P=.0081) more TGF-beta2-expressing macrophages/microglial cells in glioses of ring hemorrhages and Dürck's granulomas, and significantly (P=.0022) more TGF-beta3-expressing smooth-muscle cells and endothelial cells of brain vessels with sequestration. It is concluded that focal accumulation of TGF-beta1, -beta2, and -beta3 provides evidence for their involvement in the reorganization process of the brain parenchyma, immunologic dysfunction, and endothelial cell activation in patients with CM.
Human Fetal Lung Fibroblasts: In Vitro Study of Repetitive Magnetic Field Exposure at 0.2, 1.0, and 1.5 T
2000-06-01

PURPOSE: To evaluate whether repetitive exposure to magnetic fields of 0.2, 1.0, and 1.5 T affect the growth of human fetal lung fibroblasts (HFLFs). MATERIALS AND METHODS: Cultured HFLFs were exposed to static magnetic fields of 0.2, 1.0, and 1.5 T for 1 h/d for 5 consecutive days. Control groups were kept under identical environmental conditions, apart from the magnetic field, during the experiments. Cell cycle analysis for synchronously and nonsynchronously growing cells was performed. Population doublings (PDs) were calculated. To rule out midterm effects, proliferation kinetics of the cells were analyzed for 21 days. RESULTS: Cell cycle analysis of synchronized and nonsynchronized cells did not reveal statistically significant differences between the exposed and control cells. The PDs did not indicate any growth modulation during exposure. Proliferation kinetics did not provide any hint of midterm growth modulation effects of repetitive magnetic field exposure. CONCLUSION: Repetitive magnetic field exposure does not exert any growth-modulating effect on overall cell growth and cell cycle distribution of cultured HFLFs. Midterm effects due to magnetic field exposure were not found.