julilili42/papers huggingface dataset:
Osteodensitometry of human heel bones by MR spin‐echo imaging: Comparison with MR gradient‐echo imaging and quantitative computed tomography
2001-07-20

Abstract The aim of the study was to investigate whether quantitative magnetic resonance (MR) fast spin‐echo (FSE) imaging with moderate spatial resolution enables osteodensitometry in peripheral yellow bone marrow. Signal intensities in T1‐weighted FSE images from yellow bone marrow indicate the amount of adipose tissue per volume. The signal intensity in marrow regions with spongy bone was assessed and compared to signal intensity of pure fatty marrow (100%). Heel bones of 30 patients with suspected osteoporosis were analyzed and the FSE images were compared with results from parallel MR gradient‐echo (GE) imaging and quantitative computed tomography (QCT) examinations. High correlation was found between FSE imaging and QCT [r = 0.91 in the dorsal region of interest (ROI); r = 0.86 in ventral ROI]. Linear correlation coefficients between GE imaging and QCT were slightly lower in the dorsal part (r = –0.86) and considerably lower in the ventral part (r = –0.68). Correlation between the two MR techniques amounted to r = –0.72/–0.61 (dorsal/ventral). The high correlation between FSE imaging and bone mineral density (BMD) allows possible clinical applications of FSE imaging for diagnosis of osteoporosis. Further improvements of the accuracy using reference phantoms might be possible. J. Magn. Reson. Imaging 2001;14:147–155. © 2001 Wiley‐Liss, Inc.
New mechanism for intermediate- and short-range nucleon-nucleon interaction
2001-07-24

Arguments against the traditional Yukawa-type approach to intermediate- and short-range interaction due to scalar-isoscalar meson exchange are presented. Instead of the Yukawa mechanism for intermediate-range attraction some new approach based on formation of the symmetric six-quark bag in the state dressed due to strong coupling to , and fields are suggested. These new mechanism offers a strong intermediate-range attraction which replaces the effective -exchange (or excitation of two isobars in the intermediate state) in traditional force models. A similar mechanism with vector -meson production in the intermediate six-quark state is expected to lead to a strong short-range spin-orbital nonlocal interaction in the system, which may resolve the long-standing puzzle of the spin-orbit force in baryons and in two-baryon systems. Illustrative examples are developed which demonstrate clearly how well the suggested new model can reproduce data. Strong interrelations have been shown to exist between the proposed microscopic model and the one-component Moscow potential developed by the authors previously and also with some hybrid models and the one-term separable Tabakin potential. The new implications of the proposed model for nuclear physics are discussed.
Increased expression and activation of poly(ADP-ribose) polymerase (PARP) contribute to retinal ganglion cell death following rat optic nerve transection
2001-07-24

Excessive activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) by free-radical damaged DNA mediates necrotic cell death in injury models of cerebral ischemia-reperfusion and excitotoxicity. We recently reported that secondary retinal ganglion cell (RGC) death following rat optic nerve (ON) transection is mainly apoptotic and can significantly but not entirely be blocked by caspase inhibition. In the present study, we demonstrate transient, RGC-specific PARP activation and increased retinal PARP expression early after ON axotomy. In addition, intravitreal injections of 3-aminobenzamide blocked PARP activation in RGCs and resulted in an increased number of surviving RGCs when compared to control animals 14 days after ON transection. These data indicate that secondary degeneration of a subset of axotomized RGCs results from a necrotic-type cell death mediated by PARP activation and increased PARP expression. Furthermore, PARP inhibition may constitute a relevant strategy for clinical treatment of traumatic brain injury.
Electrophysiological alterations and upregulation of ATP receptors in retinal glial Müller cells from rats infected with the Borna disease virus
2001-07-24

Abstract Infection with the neurotropic Borna disease virus (BDV) causes an immune‐mediated neurological disease in a broad range of species. In addition to encephalitis, BDV‐infected Lewis rats develop a retinitis histologically characterized by the loss of most retinal neurons. By contrast, the dominating retinal macroglia, the Müller cells, do not degenerate. It is known from several models of neurodegeneration that glial cells may survive but undergo significant alterations of their physiological parameters. This prompted us to study the electrophysiology and ATP‐induced changes of intracellular Ca 2+ ‐concentration ([Ca 2+ ] i ) in Müller cells from BDV‐infected rat retinae. Freshly isolated cells were used for whole‐cell patch‐clamp recordings. Whereas neither zero current potentials nor membrane resistances showed significant alterations, the membrane capacitance increased in cells from BDV‐infected rats during survival times of up to 8 months. This process was accompanied by a decrease in K + current densities. Müller cells from BDV‐infected rats were characterized by expression of a prominent fast‐inactivating A‐type K + current which was rarely found in control cells. Moreover, the number of cells displaying Na + currents was slightly increased after BDV‐infection. ATP evoked increases in [Ca 2+ ] i in Müller cells within retinal wholemounts of both control and BDV‐infected animals. However, the number of ATP‐responding isolated cells increased from 24% (age‐matched controls) to 78% (cells from animals ≥18 weeks after infection). We conclude that in BDV‐induced retinopathy, reactive rat Müller cells change their physiological parameters but these changes are different from those in Müller cells during proliferative vitreoretinopathy in man and rabbit. GLIA 35:213–223, 2001. © 2001 Wiley‐Liss, Inc.
Prophylaxis of Restenosis With 186 Re-Labeled Stents in a Rabbit Model
2001-07-24

Background Intraluminal β-irradiation has been shown to decrease neointimal proliferation after angioplasty in experimental models. The purpose of this study was to test the technical feasibility and biological effects of 186 Re-labeled stents. Methods and Results Thirty-four New Zealand White rabbits were fed a 0.5% cholesterol diet before balloon angioplasty and insertion of Palmaz stents in the infrarenal aorta. The animals were killed 7 weeks after stent implantation. Two of 34 animals died prematurely (aortic leak, pneumonia). Control stents (n=7) were compared with 186 Re stents (2.6 MBq [n=6], 8.1 MBq [n=5], 16.0 MBq [n=6], and 25.3 MBq [n=8]). Stent application was successful in all cases. No thrombus occlusion was observed. After 7 weeks, neointima formation was 2.2±0.2 mm 2 in the control group. In the treatment groups, a dose-dependent neointima reduction was detectable (0.5±0.5 mm 2 [2.6 MBq], 0.4±0.4 mm 2 [8.1 MBq], and 0 mm 2 [16.0 MBq, 25.3 MBq]). No induction of neointimal formation was observed at the edges of the stents. Radiation resulted in delayed reendothelialization. Conclusions 186 Re stents were capable of reducing neointima formation in a dose-dependent fashion. 186 Re stents did not cause late thrombosis or neointimal induction at the stent margins in the observation period of 7 weeks.
ChemInform Abstract: Oxidation and Oxygenation of Substituted Arenes with Alkyl Hydroperoxides or Dioxygen/Mediation by Schiff‐Base Complexes
2001-07-24

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Neutron electric dipole moment: Constituent dressing and compositeness
2001-07-25

Contributions to the neutron's EDM, are calculated using a well-constrained Ansatz for the nucleon's Poincare' covariant Fadde'ev amplitude. The momentum-dependent quark dressing amplifies the contribution from the current-quarks' EDMs; and dressed-quark confinement and binding make distinguishable the effect of the two CP and T violating interactions: i gamma_5 sigma_{mu nu} (p_1-p_2)_nu and gamma_5 (p_1+p_2)_mu, where p_{1,2} are the current-quarks' momenta. The value of |d_n| obtained using the current-quark EDMs generated by a minimal three Higgs doublet model of spontaneous CP violation is close to the current experimental upper bound.
Local delivery of paclitaxel using the double‐balloon perfusion catheter before stenting in the porcine coronary artery
2001-07-25

Abstract Paclitaxel is a new cancer chemotherapeutic agent that has been approved for clinical use in patients with a variety of different cancers. Paclitaxel inhibits cell proliferation by an action on microtubules. The aim of this study was to evaluate the safety and efficacy of locally delivered paclitaxel after coronary stent implantation. A novel double‐balloon perfusion catheter was used to deliver the drug locally in the pig coronary artery. Twenty‐seven domestic pigs underwent stent implantation of the left anterior descending artery. In the treatment group (n = 11), paclitaxel (10 ml;10 μmol/l) was delivered using the double‐balloon perfusion catheter prior to stent implantation. The control group received stent implantation only (n = 16). The animals were sacrificed 4 weeks later. Vessels were perfusion‐fixed and morphometric analysis was performed using conventional techniques. In addition, the extent of injury was determined at each stent‐strut area. Correlation of local injury and neointimal thickness was evaluated by linear regression. Neointimal thickness (paclitaxel 1.0 ± 0.4 vs. control 0.7 ± 0.3 mm), neointimal area (paclitaxel 4.1 ± 2.2 vs. control 2.4 ± 1.1 mm 2 ), and the lumen area (paclitaxel 2.1 ± 1.9 vs. control 2.5 ± 0.9 mm 2 ) did not show significant differences between both groups. Medial area (3.3 ± 2.3 vs. 1.6 ± 0.4 mm 2 ) was larger in the vessels treated with paclitaxel ( P &lt; 0.05). Linear regression failed to show any difference in the response to injury between the two groups. Local delivery of paclitaxel with the double‐balloon‐perfusion catheter did not reduce neointima formation following stent implantation in native pig coronary arteries. Cathet Cardiovasc Intervent 2001;53:562–568. © 2001 Wiley‐Liss, Inc.
STAT3 is constitutively activated in Hodgkin cell lines
2001-08-01

Abstract Hodgkin disease (HD) represents a malignant lymphoma in which the putative malignant Hodgkin and Reed-Sternberg cells are rare and surrounded by abundant reactive nonmalignant cells. It has been suggested that cytokines such as interleukin-6 (IL-6) are involved in the pathogenesis of the disease. The expression of the IL-6 receptor (IL-6R) complex and its link to the activation of signal transducers and activators of transcription (STAT) molecules in HD cell lines was investigated. Gel retardation and Western blot analyses revealed a high level of constitutively activated STAT3 in 5 of 7 HD cell lines, which could not be detected in Burkitt lymphoma cell lines. Different levels of IL-6R protein were measured in various HD cell lines: L428 and Dev cells were characterized by very low levels of gp80 and gp130, on KMH2 cells only gp130 but no gp80 was detected, whereas L540, L591, HDLM2, and L1236 were positive for both gp80 and gp130, suggesting a possible autocrine stimulation of STAT3. However, a further increase in STAT3 activation on IL-6 or IL-6/soluble IL-6R stimulation was not observed. Neutralizing monoclonal antibodies against IL-6, gp80, gp130, or both receptor subunits did not affect the proliferation or the constitutive activation of STAT molecules in HD cell lines. However, the tyrosine kinase inhibitor AG490 blocked the constitutive activation of STAT3 and inhibited spontaneous growth of HD tumor cells. The evidence suggests abnormal STAT signaling and growth regulation in Hodgkin cell lines.
Anesthesia Changes Frequency Tuning of Neurons in the Rat Primary Auditory Cortex
2001-08-01

The vast majority of investigations on central auditory processing so far were conducted under the influence of an anesthetic agent. It remains unclear, however, to what extend even basic response properties of central auditory neurons are influenced by this experimental manipulation. We used a combination of chronic recording in unrestrained animals, computer-controlled randomized acoustic stimulation, and statistical evaluation of responses to directly compare the response characteristics of single neurons in the awake and anesthetized state. Thereby we were able to quantify the effects of pentobarbital/chloral hydrate anesthesia (Equithesin) on rat auditory cortical neurons. During Equithesin anesthesia, only a portion of central neurons were active and some of their basic response properties were changed. Only 29% of the neurons still had a frequency response area. Their tuning sharpness was increased under anesthesia. Most changes are consistent with an enhancement of inhibitory influences during Equithesin anesthesia. Thus when describing response properties of central auditory neurons, the animal's anesthetic state has to be taken into account.
Efficacy and Safety of Contact Transscleral Diode Laser Cyclophotocoagulation for Advanced Glaucoma
2001-08-01

Transscleral diode laser cyclophotocoagulation is an effective and safe method for the treatment of advanced, refractory glaucoma. However, repeated treatments are often necessary. Success of treatment depends on the age of patients, previous surgery, and the type of glaucoma.
Neural Correlates of Formal Thought Disorder in Schizophrenia
2001-08-01

The severity of positive FTD was inversely correlated with the level of activity in the Wernicke area, a region implicated in the production of coherent speech. Reduced activity in this area might contribute to the articulation of incoherent speech. Because of the small sample size, these findings should be considered preliminary.
Nitric Oxide Synthase 2Lambaréné(G‐954C), Increased Nitric Oxide Production, and Protection against Malaria
2001-08-01

A point mutation in the promoter of the nitric oxide synthase 2 gene (NOS2), termed NOS2(Lambaréné) (NOS2-G954C), protects heterozygous carriers against severe malaria as effectively as the sickle cell trait. In a prospective longitudinal study, 841 individual infections of initially 200 children (151 wild-type vs. 49 NOS2(Lambaréné) carriers) were monitored for 4 years, to assess the rates of malarial attacks in the 2 groups; carriers of the NOS2(Lambaréné) polymorphism were significantly less likely to experience malarial attacks than were others (P=.002). The distribution of the NOS2(Lambaréné) polymorphism was investigated in malaria-endemic areas. It was found to be present with the highest frequency in Africa and at a lower frequency in Asia. Ex vivo studies showed that cells isolated from people with this polymorphism have a 7-fold higher baseline NOS activity, compared with the levels detected in cells from subjects with the wild-type gene (P=.003).
Recognition of Point-Light Biological Motion Displays by Young Children
2001-08-01

We tested the ability of children 3–5 years of age to recognise biological motion displays. Children and adults were presented with moving point-light configurations depicting a walking person, four-legged animals (dogs), and a bird. Participants were able to reliably recognise displays with biological motion, but failed in the identification of a static (four consecutive frames taken from each sequence) version. The results indicate that, irrespective of the highly reduced and unusual structural information available in point-light displays, biological motion is sufficient for reliable recognition of human and non-human forms at an age as early as 3 years. Moreover, 5-year-olds exhibit the ceiling level of recognition. The findings are discussed in the context of the neuropsychological and brain mechanisms involved in biological motion perception.
Plasma clearance of iodine contrast media as a measure of glomerular filtration rate in critically ill patients
2001-08-01

These findings indicate that the determination of plasma clearance of iohexol/iopromide is a simple, rapid, and accurate method that can indeed be used for estimating GFR in ICU patients with normal renal function or even different degrees of renal insufficiency.
Ultraviolet exposure in the Ironman triathlon
2001-08-01

The International Radiation Protection Agency has issued guidelines for professional UV exposure. Ironman triathletes considerably exceeded these limits of exposure similar to other outdoor sports. Professional and amateur athletes should be aware of hazards caused by UV radiation. Adequate protection by water-resistant sunscreens and clothing as well as training and competition schedules with low sun exposure seem to be a reasonable recommendation.
The randomized z-buffer algorithm
2001-08-01

We present a new output-sensitive rendering algorithm, the randomized z-buffer algorithm. It renders an image of an arbitrary three-dimensional scene consisting of triangular primitives by reconstruction from a dynamically chosen set of random surface sample points. This approach is independent of mesh connectivity and topology. The resulting rendering time grows only logarithmically with the numbers of triangles in the scene. We were able to render walkthroughs of scenes of up to 1014 triangles at interactive frame rates. Automatic identification of low detail scene components ensures that the rendering speed of the randomized z-buffer cannot drop below that of conventional z-buffer rendering. Experimental and analytical evidence is given that the image quality is comparable to that of common approaches like z-buffer rendering. The precomputed data structures employed by the randomized z-buffer allow for interactive dynamic updates of the scene. Their memory requirements grow only linearly with the number of triangles and allow for a scene graph based instantiation scheme to further reduce memory consumption.
The Adapter Protein Apoptotic Protease-activating Factor-1 (Apaf-1) Is Proteolytically Processed during Apoptosis
2001-08-01

Apoptotic protease-activating factor-1 (Apaf-1), a key regulator of the mitochondrial apoptosis pathway, consists of three functional regions: (i) an N-terminal caspase recruitment domain (CARD) that can bind to procaspase-9, (ii) a CED-4-like region enabling self-oligomerization, and (iii) a regulatory C terminus with WD-40 repeats masking the CARD and CED-4 region. During apoptosis, cytochrome c and dATP can relieve the inhibitory action of the WD-40 repeats and thus enable the oligomerization of Apaf-1 and the subsequent recruitment and activation of procaspase-9. Here, we report that different apoptotic stimuli induced the caspase-mediated cleavage of Apaf-1 into an 84-kDa fragment. The same Apaf-1 fragment was obtained in vitro by incubation of cell lysates with either cytochrome c/dATP or caspase-3 but not with caspase-6 or caspase-8. Apaf-1 was cleaved at the N terminus, leading to the removal of its CARD H1 helix. An additional cleavage site was located within the WD-40 repeats and enabled the oligomerization of p84 into a approximately 440-kDa Apaf-1 multimer even in the absence of cytochrome c. Due to the partial loss of its CARD, the p84 multimer was devoid of caspase-9 or other caspase activity. Thus, our data indicate that Apaf-1 cleavage causes the release of caspases from the apoptosome in the course of apoptosis.
Antiphosphatidylserine antibodies are elevated in normal tension glaucoma
2001-08-01

Summary The two main entities of open-angle glaucoma are primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG). Both diseases may be associated with autoimmune processes. Therefore, IgG and IgM antibodies to phospholipids (APL) and their subspecies cardiolipin (ACL), phosphatidylserine (APS) and β2-glycoprotein (β2GP) were determined in 43 NTG patients, 40 POAG patients and 40 healthy controls in a prospective study. The most prominent observation was the increase in APS concentrations in NTG patients (IgG 20·6 ± 2·7 U/ml, IgM 24·4 ± 3·4 U/ml) compared with POAG patients (IgG 8·8 ± 1·2 U/ml, IgM 11·0 ± 1·7), and controls (IgG 7·7 ± 1·3 U/ml, IgM 12·8 ± 1·5 U/ml). APS may be important due to their binding specificity to phosphatidylserine molecules which become accessible during apoptosis; this in turn may lead to local thrombosis.
Differential activation in parahippocampal and prefrontal cortex during word and face encoding tasks
2001-08-01

Episodic encoding is the first step in the formation of a memory trace. The relation between type of stimulus material and regional brain activation is not fully understood. We measured brain activation using fMRI in 12 healthy subjects during two experiments, word and face encoding. A widespread network of common activations in both tasks was present in the bilateral frontal (BA44/45), occipital (BA17/18/19) and fusiform gyri (BA37) as well as the right hippocampal formation (BA30). A region-of-interest-analysis for the hippocampal formation and dorsolateral prefrontal cortex (DLPFC) was performed additionally. During face encoding the right dorsal and during word encoding the bilateral ventral hippocampal region was activated. In the prefrontal cortex a lateralization to the left side was present only for word encoding. During encoding, activation in the inferior frontal and hippocampal cortex is modulated by the type of stimulus material.
Differential expression and regulation of Na+/H+exchanger isoforms in rabbit parietal and mucous cells
2001-08-01

Several Na + /H + exchanger (NHE) isoforms are expressed in the stomach, and NHE1 and NHE2 knockout mice display gastric mucosal atrophy. This study investigated the cellular distribution of the NHE isoforms NHE1, NHE2, NHE3, and NHE4 in rabbit gastric epithelial cells and their regulation by intracellular pH (pH i ), hyperosmolarity, and an increase in cAMP. Semiquantitative RT-PCR and Northern blot experiments showed high NHE1 and NHE2 mRNA levels in mucous cells and high NHE4 mRNA levels in parietal and chief cells. Fluorescence optical measurements in cultured rabbit parietal and mucous cells using the pH-sensitive dye 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein and NHE isoform-specific inhibitors demonstrated that in both cell types, intracellular acidification activates NHE1 and NHE2, whereas hyperosmolarity activates NHE1 and NHE4. The relative contribution of the different isoforms to pH i - and hyperosmolarity-activated Na + /H + exchange in the different cell types paralleled their relative expression levels. cAMP elevation also stimulated NHE4, whereas an increase in osmolarity above a certain threshold further increased NHE1 and not NHE4 activity. We conclude that in rabbit gastric epithelium, NHE1 and NHE4 regulate cell volume and NHE1 and NHE2 regulate pH i . The high NHE1 and NHE2 expression levels in mucous cells may reflect their special need for pH i regulation during high gastric acidity. NHE4 is likely involved in volume regulation during acid secretion.