bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single dose and steady state pharmacokinetics and pharmacodynamics of the ACE‐inhibitor imidapril in hypertensive patients
Authors: Harder Sebastian , Thürmann Petra A. , Ungethüm Wolfram 
Published: November 2003

Aims
To investigate the pharmacokinetic profile of the ACE‐inhibitor imidapril in 10 hypertensive patients after a first single dose (10 mg) and after 28 days therapy with imidapril 10 mg once daily.
Methods
Cmax, tmax, t1/2 and AUC of imidapril and imidaprilat were obtained. ACE‐activity and arterial blood pressure during imidapril were corrected by a preceding placebo‐investigation.
Results
The AUC of imidapril was 140 (43 s.d.) ng ml−1 h after the first dose and 123 (34 s.d.) ng ml−1 h at steady state. AUC of the active moiety imidaprilat averaged 211 (101 s.d.) ng ml−1 h after the first dose and 240 (55 s.d.) ng ml−1 h at the steady state investigation. Maximal ACE‐inhibition was 75% after the single dose as well as at steady state. ACE inhibition before drug intake at day 28 (i.e. trough) was 50%. The (placebo‐corrected) maximal drop in diastolic blood pressure after imidapril was 22 mmHg after the first dose and 25 mmHg at steady state. Exploratory analysis of imidaprilat plasma concentration vs effect profiles suggests a hyperbolic concentration effect relationship where data of the single dose contribute to the ascending part of an Emax‐curve, whereas the plateau around Emax is maintained at steady state.
Conclusions
In this group of hypertensive patients, the pharmacokinetic profile and the drop in ACE‐activity as well as in blood pressure seen after a single dose of imidapril and at steady state were similar. The initial response to a test dose might therefore predict the response during chronic dosing.
Concentrations and effects of buspirone are considerably reduced by rifampicin
Authors: Lamberg T. S. , Kivistö K. T. , Neuvonen P. J. 
Published: November 2003

Aims
The effects of rifampicin on the pharmacokinetics and pharmacodynamics of buspirone, a non‐benzodiazepine anxiolytic agent, were investigated.
Methods
In a randomized, placebo‐controlled cross‐over study with two phases, 10 young healthy volunteers took either 600 mg rifampicin or matched placebo once daily for 5 days. On day 6, 30 mg buspirone was administered orally. Plasma buspirone concentrations and effects of buspirone were measured up to 10 h.
Results
The total area under the plasma buspirone concentration‐time curve after rifampicin was 10.4% (95% CI, 6.3–14.5%) of that after placebo (1.64±0.35 ng ml−1 h vs 22.0±15.1 ng ml−1 h (mean±s.d.); P<0.01). Rifampicin decreased the peak plasma concentration of buspirone from 6.6±3.7 ng ml−1 to 0.84±0.23 ng ml−1 (P<0.01) and the half‐life from 2.8±0.7 h to 1.3±0.5 h (P<0.01). A significant (P<0.05) reduction in the effects of buspirone was observed in three of the six psychomotor tests employed (postural sway test with eyes closed, subjective drowsiness and overall drug effect) after rifampicin pretreatment.
Conclusions
The strong interaction between rifampicin and buspirone is probably mostly due to enhanced CYP3A4‐mediated first‐pass metabolism of buspirone. Buspirone will most likely show a greatly reduced anxiolytic effect when used together with rifampicin or other potent inducers of CYP3A4 such as phenytoin and carbamazepine.
Multifocal motor neuropathy caused by a B‐cell lymphoma producing a monoclonal IgM autoantibody against peripheral nerve myelin glycolipids GM1 and GD1b
Authors: Noguchi Masaaki , Mori Kiyoshi , Yamazaki Shigetaka , Suda Kouichi , Sato Naotake , Oshimi Kazuo 
Published: November 2003

Summary.  Various data support the pathogenetic significance of serum IgM autoantibodies against glycolipid GM1 in patients with multifocal motor neuropathy. Although some patients with this neuropathy have an extraneural lymphoma, IgM anti‐GM1 glycolipid autoantibodies have not been investigated in these cases. We found IgM anti‐GM1 autoantibody in the serum of a 52‐year‐old man who developed multifocal motor neuropathy that was associated with an extraneural diffuse large B‐cell lymphoma. An autopsy showed severe widespread demyelination without lymphoma cell infiltration in the peripheral nerves. Immunofluorescent flow cytometry and thin‐layer chromatographic immunostaining demonstrated that most of the anti‐GM1 antibody in the serum was monoclonal IgM of λ type, which was also demonstrable in secretory form on lymphoma cells. The antibody showed affinity for the Galβ1‐3GalNAc terminal disaccharide of glycolipids GM1 and GD1b, which both are widespread in peripheral nerve myelin. Enzyme‐linked immunosorbent assay demonstrated that this antibody was much more abundant in lymphoma cell culture supernatant than in normal lymphocyte culture supernatant. Thus, our patient's B‐cell lymphoma cells produced a monoclonal IgM λ autoantibody against this terminal disaccharide residue. This antibody bound to glycolipids GM1 and GD1b in peripheral motor nerve myelin, presumably initiating formation of destructive immune complexes that caused multifocal motor neuropathy.
Proliferative response of mouse spermatogonial stem cells after irradiation: a quantitative model analysis of experimental data
Authors: Judas L. , Bentzen S. M. , Hansen P. V. , Overgaard J. 
Published: November 2003

AbstractThe testes of CDF1 mice were irradiated with single doses of X‐rays ranging from 2–16 Gy. The number of haploid cells in the testis at different times after irradiation (42–350 days) was determined by one‐parameter flow cytometry both for irradiated animals and for age‐matched controls. Based on literature data on the kinetics of the spermatogenesis in mice, a mathematical model of the (hierarchical) germ tissue was developed. Using this model, the processes of radiation‐induced cell loss and subsequent recovery were simulated and free parameters of the model were estimated by fitting the model prediction to the experimental data. One of the aims of the study was to investigate the kinetic behaviour of spermatogonial stem cells and the corresponding control mechanisms.In order to fit the data, the model has to include the following features: (i) A preferential self‐repopulation of spermatogonial stem cells following tissue injury. The model‐estimated probability of a self‐renewing division rises from 50% (the steady‐state value) to 95% if the stem‐cell population is reduced to 10% of its normal size. (ii) A relatively low, almost constant turnover rate of the stem‐cell compartment. It is suggested by the analysis that less than 10% of the permatogonial stem cells present in the testis divide per day, regardless of the degree of cellular depletion. (iii) A mechanism responsible for incomplete recovery. The observed incomplete recovery of spermatogenesis after single doses exceeding 10 Gy can be described quantitatively assuming that the stem cells are organized into discrete proliferative structures, the number of cells per structure being about 60.
Genesis and evolution of high‐ploidy tumour cells evaluated by means of the proliferation markers p34cdc2, cyclin B1, PCNA and 3[H]‐thymidine
Authors: Baroja A. , De La Hoz C. , Alvarez A. , Ispizua A. , Bilbao J. , De Gandarias J. M. 
Published: November 2003

AbstractAlthough cell polyploidization is not an infrequent event in mammalian cells and is common in tumours, the mechanisms involved are not well understood. Using the murine B16 cell line as a model, we evaluated the role of some key proteins involved in cell cycle progression: p34cdc2, cyclin B1 and PCNA. By means of flow cytometry, we showed that both in modal‐ and in high‐ploidy subpopulations, almost all cells were p34cdc2‐positive. In the modal‐ploidy subpopulation only 17.1% cells were cyclin B1‐positive and 85.6% PCNA‐positive; in contrast, in the high‐ploidy subpopulation up to 91.8% cells were cyclin B1‐positive and 97.3% cells were PCNA‐positive (P < 0.001). Immunofluorescence microscopy showed that PCNA was located in the nucleus; p34cdc2, both in the nucleus and cytoplasm; and cyclin B1 yielded a cytoplasmic spotted pattern with a perinuclear reinforcement. After a 24‐h incubation with 3[H]‐thymidine followed by withdrawal of the isotope, high‐ploidy cells remained labelled 8 days after thymidine withdrawal, in contrast to modalploidy cells. Taken together, our results suggest that polyploid cells are not quiescent, their cell cycle is longer than that of the modal‐ploidy population, and they maintain cyclin B1 throughout the cycle, which may contribute to their genesis by impeding the exit from mitosis.
Circadian variation of DNA replication in hamster cheek pouch epithelium analysed by tritiated thymidine labelling, flow sorting and autoradiography: no resting S phase cells in the normal epithelium
Authors: Larsen J. K. , Møller U. , Christensen I. J. , Christiansen J. 
Published: November 2003

AbstractIn the normal hamster cheek pouch epithelium, cell proliferation takes place with a pronounced circadian rhythm. We tested our previous hypothesis that all cells having S phase DNA content are actively synthesizing DNA and thus participating in the daily cohort of proliferating cells. We found no evidence of resting S phase cells in the normal epithelium. Using labelling with tritiated thymidine followed by fluorescence activated cell sorting according to DNA content and by autoradiography of the sorted nuclei, it was demonstrated that during the 24 h period almost all cells with mid S phase DNA content were active in DNA synthesis.
Isolation and culture of hamster ectoplacental cone trophoblasts: an in vitro study on the cell types and their growth pattern
Authors: Pande S. , Shukla R. , Mehrotra P. K. , Kamboj V. P. 
Published: November 2003

AbstractThe method of isolation of trophoblast cell types from ectoplacental cone of hamster embryo of day 8 post coitum (plug day as day 1) and examination of their growth pattern in vitro is presented in this study. Based on their size, three types of trophoblast cells were identified: (1) the smaller cells having clear cytoplasm formed the major portion (70% to 80%) of the total cell population (2) moderately bigger cells having mono or binucleated appearance and containing minute granules in the nuclear region formed 5% to 10% and (3) extra large and multinucleated cells shared 10% to 20% of the total cell number. While the smaller and slightly bigger cells showed moderate growth the larger ones had extensive growth and were seen to acquire different shapes on extending the duration of culture, such as fusiform, dumb‐bell, polygonal, rectangular or flowery. The extremities of the cytoplasmic growth of these cells were seen to be thickened at one end giving the impression of a pad‐like structure. The significance of these adaptations are not known at present.
Effects of calcitonin gene‐related peptide and interleukin 6 on myoblast differentiation
Authors: Okazaki S. , Kawai H. , Arii Y. , Yamaguchi H. , Saito S. 
Published: November 2003

AbstractEffects of calcitonin gene‐related peptide (CGRP) and interleukin 6 (IL‐6) on muscle cell differentiation were studied using cultured rat myoblasts (L6 cells). Cell morphology and the amounts of the messenger RNAs (mRNAs) of myogenin and Myf‐5, DNA content, creatine kinase (CK) activity, and myoglobin (Mb) content in the cultured cells were examined serially over 10 days of culture. In the presence of CGRP or IL‐6, the mRNAs of myogenin and Myf‐5 were expressed earlier and at a higher concentration in the treated cells than in the control cells. The ratios of CK activity to DNA content (CK/DNA) and of Mb content to DNA content (Mb/DNA) on day 10 of culture also were greater than in the control cells. Furthermore, the mRNAs of myogenin and Myf‐5 in cultured cells incubated with both CGRP and IL‐6 increased more rapidly than in cells cultured with CGRP or IL‐6 alone, and the ratios of CK/DNA and Mb/DNA on day 10 were more than twice those in the presence of CGRP or IL‐6. These findings indicate that both CGRP and IL‐6 facilitate the differentiation of myoblasts and may have an additive effect.
Expression of proliferation‐associated nuclear autoantigens, p330d/CENP‐F and PCNA, in differentiation and in drug‐induced growth inhibition using two‐parameter flow cytometry
Authors: Báez A. , Torres K. , Tan E. M. , Pommier Y. , Casiano C. A. 
Published: November 2003

Abstractp330d/CENP‐F is a recently described nuclear autoantigen that was detected in PHA‐stimulated but not in resting peripheral lymphocytes. This protein accumulates in the nucleus during S‐phase and reaches maximum levels during the G2 and M phases of the cell cycles. We compared the expression of p330d/CENP‐F and proliferating cell nuclear antigen (PCNA) during the induction of terminal myeloid differentiation of HL‐60 tumour cells. HL‐60 cells were induced to differentiate with retinoic acid (RA), dimethyl sulfoxide (DMSO), and 3‐nitrobenzothiazolo [3,2‐]quinolinium (NBQ), and collected at different intervals. Control and treated cells were analyzed by two‐parameter flow cytometry using propidium iodide and antibodies to p330d/CENP‐F and PCNA. The percentage of p330d/CENP‐F and PCNA positive cells was found to be proportional to the percentage of proliferating cells. After two cell cycles (65 h), the percentage of p330d/CENP‐F and PCNA positive cells was reduced proportionately to the number of cells that had differentiated. Reduction in the expression of both antigens was completed after 120 h when 80% to 85% of the cells were arrested in G1 and displayed the mature phenotype. The expression of p330d/CENP‐F and PCNA was also assessed in the growth inhibition of HT‐29 cells induced by various concentrations of camptothecin (CPT), etoposide (VP‐16), and aphidicolin (APH). There was a dose‐dependent displacement of cells to late S‐phase by CPT while VP‐16 induced cells to accumulate in G2+ M, and as expected these effects caused a strong increase in the cellular levels of both antigens. The arrest of cells in G1 by APH led to a significant decrease in their expression. The dramatic reduction in p330d/CENP‐F levels during differentiation, and the correlation of its expression with the cell cycle effects of the cytotoxic drugs are consistent with the behaviour expected for a proliferation marker.
p53 mutations associated with increased sensitivity to ionizing radiation in human head and neck cancer cell lines
Authors: Servomaa K. , Kiuru A. , Grénman R. , Pekkola‐Heino K. , Pulkkinen J. O. , Rytömaa T. 
Published: November 2003

The p53 tumour suppressor gene is activated following cellular exposure to DNA‐damaging agents. The functions of wild‐type p53 protein include transient blocking of cell cycle progression, direct or indirect stimulation of DNA repair machinery and triggering of apoptosis if DNA repair fails. Therefore, the status of p53 protein may be critically associated with tumour cell radiosensitivity.In the present study we examine the intrinsic radiosensitivity of 20 human carcinoma cell lines derived from 15 patients with different types of head and neck tumour. Radiosensitivities were measured in a 96‐well plate clonogenic assay in terms of the mean inactivation dose, surviving fraction at 2 Gy, and constants α and β in the linear quadratic survival curve. The p53 allele status was determined by amplifying exons 4–10 by the polymerase chain reaction (PCR), screening for mutations using single‐strand conformation polymorphism (SSCP) analysis and determining the exact type and location of a mutation by direct sequencing. The results showed that prevalence of p53 mutations in squamous cell carcinoma (SCC) cell lines is high (80%), and that deletion of one or both wild‐type alleles is common (75%). Intrinsic radiosensitivity of the cell lines varied greatly in terms of mean inactivation dose, from 1.4±0.1 to 2.6±0.2 Gy. Radiosensitivity correlated well with the p53 allele status so that cell lines carrying a wild‐type p53 allele were significantly (P<0.01) more radioresistant (mean inactivation dose 2.23±0.15 Gy) than cell lines which lacked a wild‐type gene (1.82±0.24 Gy).Evaluation of our own results and those published in the literature lead us to conclude that absence of the wild‐type p53 allele in human head and neck cancer cell lines is associated with increased radiosensitivity. However, the sensitivity is also strongly dependent on the exact type and location of the p53 mutation.
Molecular characterization of the gene locus of the human cell proliferation‐associated nuclear protein defined by monoclonal antibody Ki‐67
Authors: Duchrow M. , Schlüter C. , Wohlenberg C. , Flad H‐D. , Gerdes J. 
Published: November 2003

AbstractThe human antigen defined by the monoclonal antibody Ki‐67, the ‘Ki‐67 protein’, is an ubiquitously expressed human nuclear protein strictly associated with cell proliferation and is widely used in routine pathology as a ‘proliferation marker’ to measure the growth fraction in human tumours. In immunoblots of proteins from proliferating cells, Ki‐67 detects two bands with the apparent molecular weights of 345 and 395 kDa. Recently we reported on the cloning and sequencing of the complete cDNA of the Ki‐67 protein. We found two isoforms of cDNA with full lengths of 11.4 and 12.5 kb, respectively, likely formed by the alternative splicing of exon 7. The remarkable exon 13 at the ‘centre’ of this gene contains 16 homologous segments of 366 bp (Ki‐67 repeats), each including a highly conserved new motif of 66 bp (Ki‐67 motif). Computer analyses confirmed that the cDNAs encode for a new class of nuclear proteins.The complete gene locus of the Ki‐67 protein, comprising a 74 bp 5′ region and a 264 bp 3′ region, has been sequenced and aligned to a continuous sequence of 29 965 bp length located on chromosome 10q25‐ter. The gene is organized in 15 exons with sizes from 67 to 6845 bp and in 14 introns with sizes from 87 to 3569 bp. Three introns contain homologue copies of ‘Alu‐repeats’. Interestingly, the introns flanking the alternative spliced exon 7 are free of any consensus donor and acceptor splicing signal. All other intron‐exon transitions contained a potential branch site. The complete 5′ region including the first two exons represents a CpG‐rich island. We found the transcription initiation site in exon two adjacent to the consensus sequence of a cap site. Upstream of this cap site no TATA‐ or CCAAT‐box could be located, but downstream we found two remarkable directly repeated elements of 24 bp lengths each containing a TATA box in inverse orientation.
Flow cytometric BrdUrd‐pulse‐chase study of X‐ray‐induced alterations in cell cycle progression
Authors: Higashikubo R. , Ragouzis M. , Roti J. L. Roti 
Published: November 2003

AbstractTo better understand how the flow cytometric bromodeoxyuridine (BrdUrd)‐pulse‐chase method detects perturbed cell kinetics we applied it to measure cell cycle progression delays following exposure to ionizing radiation. Since this method will allow both the use of asynchronous cell populations and the determination of the alterations in cell cycle progression specific to cells irradiated in given cell cycle phases, it has a significant advantage over laborious synchronization methods. Exponentially growing Chinese hamster ovary (CHO) K1 cells were irradiated with graded doses of X‐rays and pulse‐labelled with BrdUrd immediately thereafter. Cells were subcultured in a BrdUrd‐free medium for various time intervals and prepared for flow cytometric analysis. Of five flow cytometric parameters examined, only those that involved cell transit through G2, i.e. the fraction of BrdUrd‐negative G2 cells and the fraction of BrdUrd‐positive cells that had not divided, showed radiation dose‐dependent delays. The magnitude of the effects indicates that the cells irradiated in G2 and in S are equally delayed. S phase transit of cells irradiated in S or in G1 did not appear to be affected. There were apparent changes in flow of cells out of G1, which could be explained by the delayed entry of G2 cells into the compartment because of G2 arrest. Thus, in asynchronous cells the method was able to detect G2 delay in those cells irradiated in S and G2 phases and demonstrate the absence of cell‐cycle delays in other phases.
Liver and plasma concentrations in paf‐acether and its precursors after partial hepatectomy
Authors: Lombard M‐N. , Izzo A. A. , Benhaddi M. , Natour J. , Benveniste J. 
Published: November 2003

AbstractLiver and plasma concentrations in paf‐acether (paf) and related phosphocholines, i.e. lysopaf and the ether lipid 1‐O‐alkyl‐2‐acyl‐sn‐glycero‐3‐phosphocholine (AAGPC) were studied in rats following two‐third hepatectomy. We report a rapid increase in hepatic content of the 3 phospholipids at early steps of the regeneration process, when hepatocytes are switching from G0 to G1 (time 2–6 h). Later on, throughout G1 and at the G1‐S transition, these concentrations decreased progressively. They were back to sham‐operated or intact control levels at 50 h. In the plasma of hepatectomized animals, no comparable changes were detected. However, an increase in both circulating paf and lipoprotein‐bound paf concentrations was measured during the regenerating response. This report is, to our knowledge, the first one on paf level variations following 2/3 hepatectomy. In rats, partial resection of the liver was shown to initiate rapid and complex cascades of biochemical changes involving growth factors, neurotransmitters and interleukins among others. Our data are in good agreement with reported increases in both total phospholipid content and synthesis of phosphatidylcholine, a paf precursor, in the regenerating liver. At present, the possible functional significance of high paf concentrations measured over the ‘priming’ stage of the induced proliferative wave is suggested as a working hypothesis. However, on the one hand, the observed paf response is noteworthy in view of its cytokine‐related action, i.e. stimulation of IL‐6 production by different cell types (endothelial, macrophagic). On the other hand, it could represent an in vivo confirmation of previously reported in vitro paf effects inducing c‐fos and c‐jun expression, two members of the so‐called ‘cellular immediate‐early gene’ family.
Spontaneous germ cell death in the testis of the adult rat takes the form of apoptosis: re‐evaluation of cell types that exhibit the ability to die during spermatogenesis
Authors: Blanco‐Rodríguez J. , Martínez‐García C. 
Published: November 2003

AbstractSpontaneous germ cell degeneration occurs in the testis of the adult rat. Accumulating data supports the idea that this degeneration takes place via apoptosis. We have determined that morphology, acridine orange staining and ultrastructural features of these cell deaths clearly take the form of apoptosis. Furthermore, with acridine orange staining it was possible to detect a cell population showing early signs of death. The characterization of the main morphological features of these cells allowed us to identify several steps of maturing germ cells undergoing degeneration that have not previously been described. We have reevaluated in toluidine blue stained semithin sections the germ cell types that undergo cell death at every stage of the spermatogenic cycle in the adult rat and concluded that, spermatogonia undergo cell death coinciding with their mitotic peaks, spermatocytes during preleptotene, leptotene, zygotene, pachytene and during metaphase I and spermatids during all their maturation steps. The biological significance of these cell deaths, at these steps of germ cell development, in relation to apoptosis, is discussed.