julilili42/papers huggingface dataset:
Function and Dynamics of Auxin and Carbohydrates during Earlywood/Latewood Transition in Scots Pine
2001-04-01

Abstract In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development.
Characterization of the Importance ofStaphylococcus epidermidisAutolysin and Polysaccharide Intercellular Adhesin in the Pathogenesis of Intravascular Catheter–Associated Infection in a Rat Model
2001-04-01

A rat central venous catheter (CVC) infection model was used to assess the importance of the proteinacious autolysin (AtlE) and the polysaccharide intercellular adhesin (PIA) in the pathogenesis of Staphylococcus epidermidis CVC-associated infection. Wild-type (wt) S. epidermidis O-47 was significantly more likely to cause a CVC infection than was either of the isogenic mutant strains (AtlE-negative [O-47mut1] or PIA-negative [O-47mut2]). Bacteria were retrieved from the explanted catheters of 87.5% of rats inoculated with S. epidermidis O-47, compared with 25% of rats challenged with either S. epidermidis O-47mut1 or O-47mut2 (P=.007). Peripheral bacteremia was documented in 75% of rats challenged with S. epidermidis O-47, compared with 12.5% and 25% challenged with O-47mut1 and O-47mut2, respectively (P=.009). Metastatic disease was more common in rats inoculated with wt S. epidermidis, compared with AtlE- or PIA-deficient mutants. These results confirm the importance of initial adherence, associated with AtlE, and biofilm production, mediated by PIA, in the pathogenesis of S. epidermidis experimental CVC infection.
Serum Response Factor Is Required for Immediate-Early Gene Activation yet Is Dispensable for Proliferation of Embryonic Stem Cells
2001-04-01

Addition of serum to mitogen-starved cells activates the cellular immediate-early gene (IEG) response. Serum response factor (SRF) contributes to such mitogen-stimulated transcriptional induction of many IEGs during the G0-G1 cell cycle transition. SRF is also believed to be essential for cell cycle progression, as impairment of SRF activity by specific antisera or antisense RNA has previously been shown to block mammalian cell proliferation. In contrast, Srf(-/-) mouse embryos grow and develop up to E6.0. Using the embryonic stem (ES) cell system, we demonstrate here that wild-type ES cells do not undergo complete cell cycle arrest upon serum withdrawal but that they can mount an efficient IEG response. This IEG response, however, is severely impaired in Srf(-/-) ES cells, providing the first genetic proof that IEG activation is dependent upon SRF. Also, Srf(-/-) ES cells display altered cellular morphology, reduced cortical actin expression, and an impaired plating efficiency on gelatin. Yet, despite these defects, the proliferation rates of Srf(-/-) ES cells are not substantially altered, demonstrating that SRF function is not required for ES cell cycle progression.
Plasmodium falciparum parasitaemia described by a new mathematical model
2001-04-01

A new mathematical model of Plasmodium falciparum asexual parasitaemia is formulated and fitted to 35 malaria therapy cases making a spontaneous recovery after primary inoculation. Observed and simulated case-histories are compared with respect to 9 descriptive statistics. The simulated courses of parasitaemia are more realistic than any previously published. The model uses a discrete time-step of 2 days. Its realistic behaviour was achieved by the following combination of features (i) intra-clonal antigenic variation, (ii) large variations of the variants' baseline growth rate, depending on both variant and case, (iii) innate autoregulation of the asexual parasite density, variable among cases, (iv) acquired variant-specific immunity and (v) acquired variant-transcending immunity, variable among cases. Aspects of the model's internal behaviour, concerning variant dynamics, as well as the respective contributions of the three control mechanisms (iii) – (v), are displayed. Some implications for pathogenesis and control are discussed.
Nucleic Acid Sequence-Based Amplification of Aspergillus RNA in Blood Samples
2001-04-01

ABSTRACT Nucleic acid sequence-based amplification (NASBA), an isothermal amplification technique, was established and evaluated for the detection of Aspergillus RNA and compared with a previously published, well-defined real-time PCR assay amplifying a region of the Aspergillus 18S rRNA gene. NASBA showed a lower detection limit of 1 CFU and detected RNA from five different clinically relevant Aspergillus species, including Aspergillus fumigatus . All 77 blood samples tested by PCR and NASBA showed identical results in both assays. Results with the NASBA technique were obtained within 6 h. Thus, the NASBA technique provided a valuable tool for sensitive, specific, fast, and reliable detection of Aspergillus RNA with potential for routine diagnosis, including the possibility to test the viability of cells.
Extragonadal seminoma: an international multicenter analysis of prognostic factors and long term treatment outcome.
2001-04-01

In patients with extragonadal seminoma, a survival rate of > 90% at 5 years is achieved with adequate cisplatin-based chemotherapy. Compared with patients with nonseminomatous extragonadal GCT, no difference in long term survival exists between patients with primary retroperitoneal or mediastinal seminoma location. Primary radiotherapy seems to be associated with a significantly higher rate of disease recurrence, although most patients will be salvaged by subsequent chemotherapy.
Detection of Microsporidia in Travelers with Diarrhea
2001-04-01

ABSTRACT We examined stool specimens of 148 returning travelers from an outpatient department for tropical diseases for the appearence of microsporidia using light microscopy and PCR. Intestinal microsporidiosis was diagnosed for five patients by light microscopy and for nine patients by PCR. Some cases were diagnosed only by PCR, indicating that the true prevalence has to be determined by highly sensitive techniques, such as PCR.
Total implantation of the implex TICA hearing amplifier implant for high-frequency sensorineural hearing loss
2001-04-01

Hearing devices may be classified as sound-producing hearing aids, electrically stimulating devices, and vibratory hearing aids. Because patients may lose physiologic cochlear amplification, hearing devices for the treatment of sensorineural hearing loss are used as signal amplifiers. The totally implantable communication assistance (TICA) device is a European-approved totally implantable vibratory amplifier implant. It picks up the sound signal transcutaneously from the external auditory canal near the eardrum, amplifies the signal, and transduces the signal into microvibrations that are delivered to the ossicular chain.
Pro12Ala Polymorphism in the Peroxisome Proliferator–Activated Receptor-γ2 Gene Is Associated With Increased Antilipolytic Insulin Sensitivity
2001-04-01

The Pro12Ala polymorphism of the peroxisome proliferator–activated receptor (PPAR)-γ2 is associated with reduced transcriptional activity in vitro and increased insulin sensitivity in humans in vivo. The mechanism by which this polymorphism influences insulin sensitivity in humans is unclear. PPAR-γ2 is mainly expressed in adipocytes, and free fatty acids released from adipose tissue are key mediators of peripheral insulin resistance. Therefore, we examined insulin suppression of lipolysis in 51 subjects without (Pro/Pro) and 17 subjects with the polymorphism (X/Ala). Both groups were lean (BMI &amp;lt;27.0 kg/m2) and matched for age, BMI, waist-to-hip ratio, and sex. The isotopically (infusion of d5 glycerol) determined glycerol rate of appearance was used as an index of lipolysis. Insulin sensitivity of lipolysis was expressed as the insulin concentration resulting in half-maximal suppression (EC50). This was directly determined during a three-step hyperinsulinemic-euglycemic clamp (n = 21) or estimated indirectly during a standard hyperinsulinemic-euglycemic clamp (n = 47). The insulin sensitivity index (ISI) of glucose disposal was 0.095 ± 0.006 μmol · kg−1 · min−1 · pmol−1 · l–1 in the control group and 0.129 ± 0.008 μmol · kg−1 · min−1 · pmol−1 · l–1 in the X/Ala group (P = 0.003). The EC50 was 56 ± 2 pmol/l in the control group and 44 ± 3 pmol/l in the X/Ala group (P = 0.001). The EC50 of lipolysis and ISI was significantly correlated (r = 0.42, P = 0.002). In conclusion, in lean subjects, the Pro12Ala polymorphism is associated with increased insulin sensitivity of glucose disposal and suppression of lipolysis. This result suggests that an altered transcriptional activity of PPAR-γ2 in X/Ala subjects either causes a more efficient suppression of lipolysis in adipose tissue, which in turn results in improved insulin-stimulated glucose disposal in muscle, or, alternatively, beneficially affects insulin signaling in both tissues independently of one another.
Rescue from death but not from functional impairment: caspase inhibition protects dopaminergic cells against 6-hydroxydopamine-induced apoptosis but not against the loss of their terminals
2001-04-01

Despite the identification of several mutations in familial Parkinson's disease (PD), the underlying mechanisms of dopaminergic neuronal loss in idiopathic PD are still unknown. To study whether caspase-dependent apoptosis may play a role in the pathogenesis of PD, we examined 6-hydroxydopamine (6-OHDA) toxicity in dopaminergic SH-SY5Y cells and in embryonic dopaminergic mesencephalic cultures. 6-OHDA induced activation of caspases 3, 6 and 9, chromatin condensation and cell death in SH-SY5Y cells. The caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-(O-methyl)fluoromethylketone (zVAD-fmk) or adenovirally mediated ectopic expression of the X-chromosomal inhibitor of apoptosis protein (XIAP) blocked caspase activation and prevented death of SH-SY5Y cells. Similarly, zVAD-fmk provided protection from 6-OHDA-induced loss of tyrosine hydroxylase-positive neurones in mesencephalic cultures. In contrast, zVAD-fmk failed to protect mesencephalic dopaminergic neurones from 6-OHDA-induced loss of neurites and reduction of [(3)H]dopamine uptake. These data suggest that, although caspase inhibition provides protection from 6-OHDA-induced death of dopaminergic neurones, the neurones may remain functionally impaired.
Cascade of Caspase Activation in Potassium-Deprived Cerebellar Granule Neurons: Targets for Treatment with Peptide and Protein Inhibitors of Apoptosis
2001-04-01

Cerebellar granule neurons (CGN) cultured in the presence of serum and depolarizing potassium concentrations undergo apoptosis when switched to serum-free medium containing physiological potassium concentrations. Here we show that processing of the key protease, caspase-3, depends on the activation of caspase-9, but not of caspase-8. Selective peptide inhibitors of caspase-9 block processing of caspase-3 and caspase-8 and inhibit apoptosis, whereas a selective inhibitor of caspase-8 blocks neither processing of caspase-3 nor cell death. The data obtained with peptide inhibitors were confirmed by adenovirally mediated ectopic expression of the cytokine response modifier A (crmA), the baculovirus protein p35, and the X chromosome-linked inhibitor of apoptosis (XIAP). Further, caspase-8-activating death receptors do not mediate apoptosis in CGN and potassium withdrawal-induced apoptosis evolves unaltered in gld or lpr mice, which harbor mutations in the CD95/CD95 ligand system. Thus, neuronal apoptosis triggered by potassium deprivation is death receptor-independent but involves the mitochondrial pathway of caspase activation.
In VivoExpression of Insulin-Like Growth Factor-Binding Protein-2 in Human Gliomas Increases with the Tumor Grade1
2001-04-01

Human central nervous system tumors and glioma cell lines highly express the insulin-like growth factor-binding protein (IGFBP)-2. As IGFBP-2 can affect tumor growth, we studied the relationship between IGFBP-2 expression and the malignancy of brain tumors in vivo. To do so, we investigated by immunohistochemistry the accumulation of IGFBP-1, -2, and -3 in 50 human gliomas classified by the WHO Malignancy Scale. Double labeling using anti-CD68 (monocytes/macrophages), antiglial fibrillary acidic protein, and anti-CD3 (T cells) antibodies was performed to further characterize the IGFBP-1, -2, and -3(+) cells. The expression of IGFBP messenger RNAs (mRNAs) was tested by RT-PCR in tumor samples from nine gliomas of different grades and in eight cell lines representing the cellular composition of human glioma. As controls, the accumulation of IGFBP-2 was investigated in normal brain and in the rat C6 glioblastoma model. IGFBP-1 and -3 accumulated in endothelial and macrophage/microglial cells. IGFBP-2(+) macrophage/microglial and glioma cells clustered in the immediate vicinity of focal necrosis of the human gliomas as well as of the rat C6 glioblastoma. The labeling score of IGFBP-1 accumulation in endothelial cells correlated negatively (P: = 0.0229), and that of IGFBP-2 accumulation in glioma cells correlated positively (P: < 0.0006) with the tumor grade of the gliomas. In addition, RT-PCR analysis confirmed mRNA expression of IGFBP-1, -2, and -3 by the gliomas and glial cells. Small amounts of IGFBP-1 and -3 mRNA, but high amounts of IGFBP-2 mRNA, were detectable in macrophage-like and glioma cell lines. The results suggest cell type-specific accumulation of IGFBP-1, -2, and -3 in human glial tumors of the brain. The increase in IGFBP-2 expression with this malignancy suggests a role of IGFBP-2 in the biology of human gliomas.
Pseudomonas aeruginosa-Induced Apoptosis Involves Mitochondria and Stress-Activated Protein Kinases
2001-04-01

ABSTRACT Pseudomonas aeruginosa , a gram-negative facultative pathogen, causes severe infections in immunocompromised and cystic fibrosis patients. However, the molecular details of the interaction between P. aeruginosa and mammalian cells are still largely unknown. Here we demonstrate that infection of human conjunctiva epithelial Chang cells with the well-characterized P. aeruginosa strain PAO-I results in rapid induction of apoptosis. Apoptosis was mediated by mitochondrial alterations, in particular mitochondrial depolarization, synthesis of reactive oxygen intermediates, and release of cytochrome c , as well as an activation of Jun N-terminal kinases (JNK). Stimulation of these events was dependent on upregulation of CD95 on infected cells, and a deficiency of CD95 or the CD95 ligand prevented mitochondrial changes, JNK activation, and apoptosis upon infection. Further, efficient apoptosis of Chang epithelial cells required infection with live P. aeruginosa , adhesion but not invasion of the bacteria, and expression of the type III secretion system in PAO-I. The data indicate a type III secretion system-dependent, sequential activation of several signaling pathways by P. aeruginosa PAO-I, resulting in apoptosis of the infected cell.
Treatment of Recurrent Malignant Sacrococcygeal Germ Cell Tumors: Analysis of 22 Patients Registered in the German Protocols MAKEI 83/86, 89, and 96
2001-04-01

PURPOSE: To evaluate therapeutic options for recurrent malignant sacrococcygeal germ cell tumors (GCT) following three-agent, cisplatinum-based, first-line chemotherapy and tumor resection. PATIENTS AND METHODS: Twenty-two patients were evaluated in 22 first-, 14 second-, five third-, and two fourth-relapse situations. One patient, who relapsed with pure teratoma, was excluded from the analysis of adjuvant treatment. RESULTS: Seventeen patients presented with an isolated local recurrence, two patients showed a distant relapse, and three patients suffered from a combined local and distant recurrence. Twelve patients achieved complete remission (CR) after surgery (n = 12) and adjuvant platinum chemotherapy (n = 10). Seven of these patients remain in continuous CR, and five patients relapsed. All patients who achieved only a partial remission developed a second relapse. Three of 14 patients could be cured after a second (or further) relapse. Altogether, 10 patients survived disease free, and 12 patients died as a result of tumor progression (n = 11) or therapy-related complications (n = 1). The completeness of salvage surgery and clinical remission status after first salvage treatment were the most important prognostic parameters. In addition, patients in first or second relapse with locally advanced or poorly responding tumors benefited from preoperative chemotherapy in combination with regional hyperthermia (RHT). In some patients after microscopically incomplete resection, irradiation at doses &gt; 45 Gy contributed to a favorable outcome. CONCLUSION: The complete resection of the local recurrence represents the cornerstone of salvage treatment. Preoperative platinum-based chemotherapy, combined with RHT in some patients, facilitates complete tumor resection. Radiotherapy should be reserved for those patients with microscopically incomplete tumor resection. As the chance of cure decreases with further relapses, it is important to establish a stringent therapeutic strategy to avoid significant treatment delays and, most importantly, insufficient local therapy.
A Novel Dark-Inducible Protein, LeDI-2, and Its Involvement in Root-Specific Secondary Metabolism inLithospermum erythrorhizon
2001-04-01

Abstract Lithospermum erythrorhizon produces red naphthoquinone pigments that are shikonin derivatives. They are accumulated exclusively in the roots of this plant. The biosynthesis of shikonin is strongly inhibited by light, even though other environmental conditions are optimized. Thus, L. erythrorhizon dark-inducible genes (LeDIs) were isolated to investigate the regulatory mechanism of shikonin biosynthesis. LeDI-2, showing the strict dark-specific expression, was further characterized by use of cell suspension cultures and hairy root cultures as model systems. Its mRNA accumulation showed a similar pattern with that of shikonin. In the intact plants LeDI-2 expression was observed solely in the root, and the longitudinal distribution of its mRNA was also in accordance to that of shikonin. LeDI-2 encoded a very hydrophobic polypeptide of 114 amino acids that shared significant similarities with some root-specific polypeptides such as ZRP3 (maize) and RcC3 (rice). Reduction of LeDI-2 expression by its antisense DNA in hairy roots of L. erythrorhizon decreased the shikonin accumulation, whereas other biosynthetic enzymes, e.g.p-hydroxybenzoic acid:geranyltransferase, which catalyzed a critical biosynthetic step, showed similar activity as the wild-type clone. This is the first report of the gene that is involved in production of secondary metabolites without affecting biosynthetic enzyme activities.
The phylogenetic relationships of argyrolagid marsupials
2001-04-01

New material of the oldest known argyrolagid marsupial Proargyrolagus bolivianus from the late Oligocene of Bolivia is described. The new specimen preserves previously unknown aspects of the anterior dentition that solve the long-standing homology problem concerning the identity (i2) of the procumbent lower incisors in argyrolagids. This new anatomical information is incorporated into a morphology-based phylogenetic analysis of all extant marsupial families and Argyrolagidae, with the aim of testing the monophyly of Paucituberculata and evaluating the relationships among extant marsupial families. Eleven features support the monophyly of Paucituberculata, the following three unique among Marsupialia: small size of the paraconid, procumbent second lower incisor, and supraoccipital without distinct lambdoid crest resulting in globular form of braincase. Paucituberculata is the sister group of an Australian clade of marsupials that includes Dromiciops, but these results are not robust, as shown by sensitivity analyses. The foramen ovale surrounded completely by the alisphenoid supports the association of Dromiciops with diprotodontians.
Determination of Interconversion Barriers by Dynamic Gas Chromatography: Epimerization of Chalcogran
2001-04-01

The four stereoisomers of chalcogran 1 ((2RS,SRS)-2-ethyl-1,6-di-oxaspiro[4.4]nonane), the principal component of the aggregation pheromone of the bark beetle pityogenes chalcographus, are prone to interconversion at the spiro center (C5). During diastereo- and enantioselective dynamic gas chromatography (DGC), epimerization of 1 gives rise to two independent interconversion peak profiles, each featuring a plateau between the peaks of the interconverting epimers. To determine the rate constants of epimerization by dynamic gas chromatography (DGC), equations to simulate the complex elution profiles were derived, using the theoretical plate model and the stochastic model of the chromatographic process. The Eyring activation parameters of the experimental interconversion profiles, between 70 and 120 C in the presence of the chiral stationary phase (CSP) Chirasil-beta-Dex, were then determined by computer-aided simulation with the aid of the new program Chrom-Win: (2R,5R)-1: deltaG(++) (298.15 K) = 108.0 +/-0.5 kJ mol(-1), deltaH(++) = 47.1+/-0.2 kJ mol(-1), deltaS(++) = -204+/-6 JK(-1) mol(-1): (2R,5S)-1: deltaG(++) (298.15 K) = 108.5+/-0.5 kJ mol(-1), deltaH(++) = 45.8+/-0.2 kJ mol(-1), deltaS(++) = -210 +/-6 J K mol(-1); (2S,5S)-1: deltaG(++) (298.15 K)= 108.1+/-0.5 kJ mol(-1), deltaH(++) = 49.3+/-0.3 kJ mol(-1), deltaS(++) = -197+/-8 J K(-1) mol(-1); (2S,5R)-1: deltaG(++) (298.15 K)=108.6+/-0.5 kJ mol(-1), deltaH(++) = 48.0+/-0.3 kJ mol(-1), deltaS(++) = -203+/-8 J K(-1) mol(-1). The thermodynamic Gibbs free energy of the E/Z equilibrium of the epimers was determined by the stopped-flow multidimensional gas chromatographic technique: deltaG(E/Z) (298.15 K)= -0.5 kJ mol(-1), deltaH(E/Z) = 1.4 kJ mol(-1) and deltaS(E/Z) = 6.3 J K(-1) mol(-1). An interconversion pathway proceeding through ring-opening and formation of a zwitterion and an enol ether/alcohol intermediate of 1 is proposed.