julilili42/papers huggingface dataset:
Telomere Length Dynamics in Normal Individuals and in Patients with Hematopoietic Stem Cell‐Associated Disorders
2001-06-01

A bstract : The telomere length in nucleated peripheral blood (PB) cells indirectly reflects the mitotic history of their precursors: the hematopoietic stem cells (HSCs). The average length of telomeres in PB leukocytes can be measured using fluorescence in situ hybridization and flow cytometry (flow FISH). We previously used flow FISH to characterize the age‐related turnover of HSCs in healthy individuals. In this review, we describe results of recent flow FISH studies in patients with selected hematopoietic stem cell‐associated disorders: chronic myelogeneous leukemia (CML) and several bone marrow failure syndromes. CML is characterized by a marked expansion of myeloid Philadelphia chromosome positive (Ph+) cells. Nevertheless, nonmalignant (Ph−) HSCs typically coexist in the bone marrow of CML patients. We analyzed the telomere length in &gt;150 peripheral blood leukocytes (PBLs) and bone marrow samples of patients with CML as well as samples of Ph‐ T‐lymphocytes. Compared to normal controls, the overall telomere fluorescence in PBLs of patients with CML was significantly reduced. However, no telomere shortening was observed in Ph‐ T‐lymphocytes. Patients in late chronic phase (CP) had significantly shorter telomeres than those assessed earlier in CP. Our data suggest that progressive telomere shortening is correlated with disease progression in CML. Within the group of patients with bone marrow failure syndromes, we only found significantly shortened telomeres (compared to age‐adjusted controls) in granulocytes from patients with aplastic anemia (AA). Strikingly, the telomere length in granulocytes from AA patients who had recovered after immunosuppressive therapy (recAA) did not differ significantly from controls, whereas untreated patients and nonresponders with persistent severe pancytopenia (sAANR) showed marked and significant telomere shortening compared to healthy donors and patients with recAA. Furthermore, an inverse correlation between age‐adjusted telomere length and peripheral blood counts was found in support of a model in which the degree of cytopenia and the amount of telomere shortening are correlated. These results support the concept of extensive proliferation of HSCs in subgroups of AA patients and suggest a potential use of telomere‐length measurements as a prognostic tool in this group of disorders as well.
Intralesional rituximab for cutaneous B-cell lymphoma
2001-06-01

Rituximab, a chimeric anti-CD20 monoclonal antibody, has been approved for systemic treatment of relapsed or refractory CD20-positive B-cell non-Hodgkin's lymphoma. As cutaneous B-cell lymphoma (CBCL) also expresses the CD20 molecule, three patients with histologically and immunohistochemically confirmed CBCL without systemic involvement were treated with low-dose intralesional rituximab in a pilot study. Single doses applied ranged from 10 to 30 mg per lesion, according to lesion extent, with a cumulative dose of up to 350 mg. Injections were given two or three times weekly for 3-5 weeks, with a second cycle after 6 weeks in one patient with incomplete remission. Complete and lasting remission was achieved in each patient; this has persisted for up to more than 1 year. The observed adverse events were of grade 1 severity. Results suggest that intralesional rituximab may be a safe and effective new therapy modality for CBCL.
Therapeutic Drug Monitoring of Clozapine in Relapse Prevention: A Five-Year Prospective Study
2001-06-01

Twenty-three outpatients with schizophrenia (ICD-10 F20.xx) treated with clozapine (CZ) as monotherapy entered a prospective study on relapse prevention. Every 4 weeks, psychopathology was assessed by the Brief Psychiatric Rating Scale (BPRS), and plasma CZ and norclozapine levels were measured. Patients were enrolled after complete remission of positive symptoms for at least 4 months according to the psychosis cluster of the BPRS and at a mean of 3.3 years after their last hospitalization. At the time of enrollment, the median BPRS total score was 29 points (range, 19-48). Within 4 months, the baseline CZ plasma level was established as the mean of CZ levels from at least four subsequent measurements. These baseline plasma levels were considered as the optimal relapse-preventing plasma CZ levels in the individual patients. When the patients were enrolled, they were considered to be prone to relapse. Relapse was defined as clinical deterioration, hospitalization, or both. Plasma levels were considered a prognostic factor, and patients were defined as at increased risk if plasma levels decreased by more than 40% from baseline CZ plasma level. The effect of plasma CZ levels on clinical outcome was evaluated by a Cox regression with plasma level as a time-dependent covariate. Within 46 months of enrollment, 32 episodes of relapse events in 10 patients were available for evaluation. Seventeen patients had a plasma level decrease of more than 40% at some point. In 12 of these, the decrease was present for more than 12% of the observation period. Eight patients of this group relapsed, and three of these had to be rehospitalized. Two patients relapsed, although their plasma levels decreased by more than 40% for less than 12% of the observation period. Within the first 2 years, relapse-free survival curves illustrate that both groups (episodes under elevated risk and episodes not under elevated risk) had identical relapse patterns, but from then on the relapse risk increased rapidly in the group with longer exposure to elevated risk. In a Cox model with a 40% decrease of plasma CZ levels as a dichotomous time-varying explanatory covariate, the risk ratio is 6 (95% confidence interval = 2-19, p = 0.003). The 10 patients who relapsed exhibited safe plasma levels (less than a 40% decrease from their baseline levels) for only 210 months, and 13 nonrelapsing patients had plasma levels defined as safe for 426 months.
Computer‐based analysis of steady‐state and transient heat transfer of small‐sized leaves by free and mixed convection
2001-06-01

Abstract In order to study convective heat transfer of small leaves, the steady‐state and transient heat flux of small leaf‐shaped model structures (area of one side = 1730 mm 2 ) were studied under zero and low (= 100 mm s −1 ) wind velocities by using a computer simulation method. The results show that: (1) distinct temperature gradients of several degrees develop over the surface of the model objects during free and mixed convection; and (2) the shape of the objects and onset of low wind velocities has a considerable effect on the resulting temperature pattern and on the time constant τ . Small leaves can thus show a temperature distribution which is far from uniform under zero and low wind conditions. The approach leads, however, to higher leaf temperatures than would be attained by ‘real’ leaves under identical conditions, because heat transfer by transpiration is neglected. The results demonstrate the fundamental importance of a completely controlled environment when measuring heat dissipation by free convection. As slight air breezes alter the temperature of leaves significantly, the existence of purely free convection appears to be questionable in the case of outdoor conditions. Contrary to the prognoses yielded by standard approximations, no quantitative effect of buoyancy on heat transfer under the considered conditions could be detected for small‐sized leaf shapes.
Sound lateralization during passive whole‐body rotation
2001-06-01

Abstract The effect of passive whole‐body rotation about the earth‐vertical axis on the lateralization of dichotic sound was investigated in human subjects. Pure‐tone pulses (1 kHz; 0.1 s duration) with various interaural time differences were presented via headphones during brief, low‐amplitude rotation (angular acceleration 400°/s 2 ; maximum velocity 90°/s; maximum displacement 194°). Subjects made two‐alternative forced‐choice (left/right) judgements on the acoustic stimuli. The auditory median plane of the head was shifted opposite to the direction of rotation, indicating a shift of the intracranial auditory percept in the direction of rotation. The mean magnitude of the shift was 10.7 μs. This result demonstrates a slight, but significant, influence of rotation on sound lateralization, suggesting that vestibular information is taken into account by the brain for accurate localization of stationary sound sources during natural head and body motion.
A novel glycosylated Cu/Zn-containing superoxide dismutase: production and potential therapeutic effect
2001-06-01

The fungal strain Humicola lutea 103 produces a naturally glycosylated Cu/Zn SOD. To improve its yield, the effect of an increased concentration of dissolved oxygen (DO) on growth and enzyme biosynthesis by the producer, cultivated in a 3 l bioreactor, was examined. Exposure to a 20% DO level caused a 1.7-fold increase of SOD activity compared to the DO-uncontrolled culture. Maximum enzyme productivity of SOD was approximately 300 x 10(3) U (kg wet biomass)(-1). The novel enzyme was purified to electrophoretic homogeneity. The presence of Cu and Zn were confirmed by atomic absorption spectrometry. The molecular mass of H. lutea Cu/Zn SOD was calculated to be 31870 Da for the whole molecule and 15936 Da for the structural subunits. The N-terminal sequence revealed a high degree of structural homology with Cu/Zn SOD from other prokaryotic and eukaryotic sources. H. lutea Cu/Zn SOD was used in an in vivo model for the demonstration of its protective effect against myeloid Graffi tumour in hamsters. Comparative studies revealed that the enzyme (i) elongated the latent time for tumour appearance, (ii) inhibited tumour growth in the early stage of tumour progression (73-75% at day 10) and (iii) increased the mean survival time of Graffi-tumour-bearing hamsters. Moreover, the fungal Cu/Zn SOD exhibited a strong protective effect on experimental influenza virus infection in mice. The survival rate increased markedly, the time of survival rose by 5.2 d and the protective index reached 86%. The H. lutea SOD protected mice from mortality more efficiently compared to the selective antiviral drug ribavirin and to commercial bovine SOD. In conclusion, our results suggest that appropriate use of the novel fungal SOD, applied as such or in combination with selective inhibitors, could outline a promising strategy for the treatment of myeloid Graffi tumour and influenza virus infection.
Synthesis and Separation of Structural Isomers of 2(3),9(10),16(17),23(24)-Tetrasubstituted Phthalocyanines
2001-06-01

The 2(3),9(10),16(17),23(24)-tetrasubstituted metalphthalocyanines 1-7 (M = In, Ni, Zn) were synthesized, as mixtures of four different structural isomers, from the corresponding 4-alkoxy-1,2-dicyanobenzenes and the appropriate metal salts. Separation of the four structural isomers was successfully achieved on a C30 alkyl phase by high-performance liquid chromatography (HPLC). The determination of the point groups of the structural isomers was carried out for 1 and 3, the composition of the structural isomers of 4-7 was accomplished by comparing their retention times and UV/Vis spectra with the data of 1 and 3. For the phthalocyanines 8-10 and the naphthalocyanines 11 and 12 only the C4h and D2h isomers could be separated.
Transendothelial Migration of Hematopoietic Progenitor Cells
2001-06-01

A bstract : There is increasing evidence that hematopoietic stem cell mobilization and homing is regulated not only by adhesion molecules and cytokines, but also by chemotactic factors that support transendothelial migration across the bone marrow sinusoidal endothelium. Many receptors for chemotactic mediators belong to the family of G protein‐coupled seven‐transmembrane receptors (7‐TMR). Signaling via G proteins, particularly G i proteins, results in a chemotactic response of the cells towards a gradient of the corresponding ligand. Recent studies have provided evidence for expression of several 7‐TMR on immature hematopoietic progenitor cells, which potentially mediate chemotactic effects: chemokine receptors (e.g., CXCR4, receptor for stromal cell‐derived factor‐1), receptors for lipid mediators (e.g., the cysteinyl leukotriene receptor cysLT1 and the peripheral cannabinoid receptor cb2), and receptors for neuroendocrine hormones (e.g., the somatostatin receptor sst2). From these studies it can be concluded that migration of hematopoietic progenitor and stem cells is controlled by a variety of chemotactic factors rather than by a single chemokine (e.g., SDF‐1). Trafficking of immature hematopoietic cells may require combined and interactive regulatory functions of these mediators.
Isolation and identification of clozapine metabolites in patient urine.
2001-06-01

Biotransformation products of the atypical neuroleptic clozapine were isolated from urine samples of three schizophrenic patients by solid-phase extraction, liquid-liquid extraction for the separation of unpolar and polar metabolites, and thin-layer chromatography followed by final purification by high-performance liquid chromatography. Their structures were elucidated by mass spectrometry and (1)H NMR spectroscopy and in some cases by enzymatic deconjugation. Besides the known metabolites desmethylclozapine, clozapine N-oxide, 8-deschloro-8-hydroxyclozapine, and 8-deschloro-8-hydroxydesmethylclozapine, the unpolar fraction contained 7-hydroxyclozapine and a compound in which the piperazine ring of clozapine was partially degraded to an ethylenediamine derivative. Novel metabolites identified in the polar fraction were the sulfate and glucuronide conjugates of 7-hydroxyclozapine N-oxide, 8-deschloro-8-hydroxyclozapine-O-glucuronide, and the O-glucuronide of N-hydroxydesmethylclozapine; further conjugates were tentatively identified as 9-hydroxydesmethylclozapine-O-sulfate and 6-hydroxyclozapine-O-sulfate. In addition, the previously described conjugates 7-hydroxydesmethylclozapine-O-sulfate, 7-hydroxyclozapine-O-glucuronide and -O-sulfate, 8-deschloro-8-hydroxydesmethylclozapine-O-glucuronide, and the quaternary ammonium glucuronide of clozapine were detected.
Functional T lymphocytes infiltrate implanted polyvinyl alcohol foams during surgical wound closure therapy
2001-06-01

SUMMARY Vacuum-assisted closure involving the implantation of polyvinyl alcohol foam is a technique recently developed for the treatment of patients suffering from either wound infection or chronic wounds. This method has been shown to improve and accelerate wound healing. However, little is known about the cell populations that infiltrate the foam, and their potential role in resolving the infection and promoting granulation tissue formation. Our study demonstrates that wound-implanted foams are mainly infiltrated with granulocytes, but that mononuclear cells, including macrophages and minor populations of T, B and natural killer lymphocytes, are also present. We show that foam-infiltrating T cells, especially CD4+ T cells, constitute a phenotypically and functionally heterogeneous population influenced by wound-infecting bacteria. Thus, T lymphocytes could play a role in wound cleansing. In addition, our data indicate that implanted polyvinyl alcohol foams might be suitable microenvironments for manipulating T cell-mediated immune responses in patients.
Secretion of Active Recombinant Human Tissue Plasminogen Activator Derivatives in Escherichia coli
2001-06-01

ABSTRACT The DNA fragment coding for kringle 2 plus serine protease domains ( K2S ) of tissue plasminogen activator (tPA) was inserted into a phagemid vector, pComb3HSS. In the recombinant vector, pComb3H- K2S , the K2S gene was fused to gpIII of ΦM13 and linked to the OmpA signal sequence. The resulting gene, rK2S-gpIII, was inducibly expressed in Escherichia coli XL-1 Blue. The protein was presented on the phage particle. To stop the expression of gpIII, a stop codon between K2S and the gpIII gene was inserted by site-directed mutagenesis. This mutated vector, MpComb3H- K2S , was transformed in XL-1 Blue. After induction with IPTG (isopropyl-β- d -thiogalactopyranoside), rK2S was found both in the periplasm as an inactive form of approximately 32% and in the culture supernatant as an active form of approximately 68%. The secreted form of rK2S was partially purified by ammonium sulfate (55%) precipitation. The periplasmic form was isolated from whole cells by chloroform extraction. The fibrin binding site of kringle 2 was demonstrated in all expressed versions (phage-bound, periplasmic, and secreted forms) using the monoclonal anti-kringle 2 antibody (16/B). Only the secreted form of rK2S revealed a fibrinogen-dependent amidolytic activity with the specific activity of 236 IU/μg. No amidolytic activity of rK2S was observed in either the periplasmic or the phage-bound form. The secretion of rK2S as an active enzyme offers a novel approach for the production of the active-domain deletion mutant tPA, rK2S, without any requirements for bacterial compartment preparation and in vitro refolding processes. This finding is an important technological advance in the development of large-scale, bacterium-based tPA production systems.
Determinants for resistance and susceptibility to microfilaraemia in Litomosoides sigmodontis filariasis
2001-06-01

Filarial infections of humans are chronic diseases. Despite an ongoing immune response, adult filariae continuously produce their offspring, the microfilariae (Mf), which are able to persist in sufficient numbers to ensure transmission. In this study, host- and parasite-derived factors, which contribute to persistence of Mf, were investigated using the filariasis model of Litomosoides sigmodontis in mice. Different strains of mice were found to differ widely in their capability to eliminate circulating Mf. Studies of congenic mouse strains showed that early and rapid clearance of Mf was mediated by activation pathways relevant to innate immunity, whereas late or delayed clearance of Mf was pre-determined by MHC-related factors. Genetic knock-out of genes for the MHC class-II molecules totally abrogated resistance. Most interestingly, the presence of only 1 adult female, but not male worms, renders all mice susceptible, irrespective of the genetic background, enabling Mf to circulate for extended periods of time. Such prolonged microfilaraemia was also observed in L. sigmodontis -infected animals challenged with heterologous Mf of Acanthocheilonema viteae . The use of cytokine gene knock-out mice showed that persistence of L. sigmodontis Mf was facilitated by IL-10, but not by IL-4 or IFN-γ. In conclusion, irrespective of a resistant or susceptible host genetic background, survival of Mf of L. sigmodontis in mice is decisively regulated by the presence of adult female L. sigmodontis which will skew and exploit immune responses to facilitate the survival and persistence of their offspring in the infected host.
MHC Class II-Regulated Central Nervous System Autoaggression and T Cell Responses in Peripheral Lymphoid Tissues Are Dissociated in Myelin Oligodendrocyte Glycoprotein-Induced Experimental Autoimmune Encephalomyelitis
2001-06-01

Abstract We dissected the requirements for disease induction of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis in MHC (RT1 in rat) congenic rats with overlapping MOG peptides. Immunodominance with regard to peptide-specific T cell responses was purely MHC class II dependent, varied between different MHC haplotypes, and was linked to encephalitogenicity only in RT1.Ba/Da rats. Peptides derived from the MOG sequence 91–114 were able to induce overt clinical signs of disease accompanied by demyelinated CNS lesions in the RT1.Ba/Da and RT1n haplotypes. Notably, there was no detectable T cell response against this encephalitogenic MOG sequence in the RT1n haplotype in peripheral lymphoid tissue. However, CNS-infiltrating lymphoid cells displayed high IFN-γ, TNF-α, and IL-4 mRNA expression suggesting a localization of peptide-specific reactivated T cells in this compartment. Despite the presence of MOG-specific T and B cell responses, no disease could be induced in resistant RT1l and RT1u haplotypes. Comparison of the number of different MOG peptides binding to MHC class II molecules from the different RT1 haplotypes suggested that susceptibility to MOG-experimental autoimmune encephalomyelitis correlated with promiscuous peptide binding to RT1.B and RT1.D molecules. This may suggest possibilities for a broader repertoire of peptide-specific T cells to participate in disease induction. We demonstrate a powerful MHC class II regulation of autoaggression in which MHC class II peptide binding and peripheral T cell immunodominance fail to predict autoantigenic peptides relevant for an autoaggressive response. Instead, target organ responses may be decisive and should be further explored.
Arabidopsis thaliana Flavoprotein AtHAL3a Catalyzes the Decarboxylation of 4′-Phosphopantothenoylcysteine to 4′-Phosphopantetheine, a Key Step in Coenzyme A Biosynthesis
2001-06-01

The Arabidopsis thaliana flavoprotein AtHAL3a is related to plant growth and salt and osmotic tolerance. AtHAL3a shows sequence homology to the bacterial flavoproteins EpiD and Dfp. EpiD, Dfp, and AtHAL3a are members of the homo-oligomeric flavin-containing Cys decarboxylase (HFCD) protein family. We demonstrate that AtHAL3a catalyzes the decarboxylation of (R)-4'-phospho-N-pantothenoylcysteine to 4'-phosphopantetheine. This key step in coenzyme A biosynthesis is catalyzed in bacteria by the Dfp proteins. Exchange of His-90 of AtHAL3a for Asn led to complete inactivation of the enzyme. Dfp and AtHAL3a are characterized by a shortened substrate binding clamp compared with EpiD. Exchange of the cysteine residue of the conserved ACGD motif of this binding clamp resulted in loss of (R)-4'-phospho-N-pantothenoylcysteine decarboxylase activity. Based on the crystal structures of EpiD H67N with bound substrate peptide and of AtHAL3a, we present a model for the binding of (R)-4'-phospho-N-pantothenoylcysteine to AtHAL3a.
Differential expression of the hexose‐regulated fungal genes AmPAL and AmMst1 within Amanita/Populus ectomycorrhizas
2001-06-01

Summary At least three fungal ‘networks’ are formed in ectomycorrhizal symbiosis: the Hartig net, the sheath and extramatrical hyphae. Since these structures have different functions regarding uptake, storage and partitioning of carbohydrates and nutrients, regulation and coordination of metabolic fluxes are of special interest for ectomycorrhizal functioning. To get some insight into structure‐specific functions, the Amanita fungal sheath was separated by microdissection from the remaining Populus roots that still contained the Hartig net. Expression of the genes coding for phenylalanine ammonium lyase ( AmPAL ) and hexose transporter ( AmMst1 ) was investigated separately for both structures by RT‐PCR. When constitutively expressed fungal genes were used as a control, the expression of AmMst1 was enhanced about six‐fold in hyphae of the Hartig net compared with those of the fungal sheath. By contrast, AmPAL was only barely detectable in the Hartig net, but highly expressed in the fungal sheath. Since in pure fungal culture both genes are regulated by monosaccharides, it is supposed that an apoplastic hexose gradient, between hyphae of the Hartig net and those of the fungal sheath, might regulate fungal gene expression and thus hyphal physiology within ectomycorrhizas.