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PubMed2005

Activity-dependent influences are greater for fibers in rat medial gastrocnemius than tibialis anterior muscle.

Skeletal muscles are highly adaptive to changes in loading or activation. A model of neuromuscular inactivity (spinal cord isolation, SI) was used to determine the role of activity-independent and -dependent neural influences on the size and myonuclei number in type-identified fibers of a fast extensor (medial gastrocnemius, MG) and flexor (tibialis anterior, TA) rat muscle. Fibers were categorized based on myosin heavy chain isoform composition. Four days after SI, all fiber types tended to atrophy and lose myonuclei, with the percent loss of myonuclei being disproportionately less than the decrease in fiber size. At 60 days after SI, all fiber types in MG and the fastest fibers in TA were significantly smaller and had fewer myonuclei than control. The disproportionate amount of atrophy resulted in a smaller myonuclear domain. These effects were greater in MG than TA, indicating that activity-dependent influences were greater in the extensor than flexor. The smaller myonuclear domains after a period of chronic inactivity suggest the presence of intrinsic mechanisms operating to maintain the genetic material necessary to recover from atrophic conditions.

Adaptation, Biological↗
PubMed1990

Marital relationships and Type A-B behavior assessed using the structured interview, Jenkins Activity Survey, and Framingham Type A Scale.

Associations between spouses' Type A/Type B Behavior and marital distress, communication, and desired relationship changes were investigated in a sample of 42 healthy Caucasian couples aged 39 to 60 years. Consistency of relationships between marital distress and behavior type (BT) across different BT measurement techniques was also evaluated. BT was measured using the Structured Interview (SI), the Jenkins Activity Survey (JAS), and the Framingham Type A Scale (FTAS). Type A behavior in women was associated with increased marital distress and communication difficulties, as reported by both men and women. Participants also desired greater relationship changes when women were Type A. Findings varied greatly across BT measures. The strongest effect occurred for the FTAS, followed by the JAS. No significant effects were found for SI-assessed BT. Results reflect the multifaceted nature of the Type A construct and may reflect gender role differences within marital relationships.

Adult↗
PubMed2003

High-resolution and high-intensity powder diffractometer at BL15XU in SPring-8.

A new ultra-high-resolution powder diffractometer for synchrotron radiation has been constructed at beamline BL15XU, SPring-8. The two-axis diffractometer is optimized for high-flux and high-coherent X-ray beams, which are provided by combining a planar undulator and a large offset rotated-inclined Si(111) double-crystal monochromator. The optics design of the diffractometer is based on transmission geometry, which employs a capillary specimen and reflection geometries using a flat-plate specimen. The intensity data are collected using a 2theta step-scan technique in both geometries. The diffractometer can be arranged in a variety of optical configurations, e.g. simple receiving slits, flat crystal analyzer of Ge(111) or Si(111), and in-vacuum-type long horizontal parallel slits. A minimum full width at half-maximum against 2theta was 0.00572 degrees at lambda = 0.63582 A for the (200) reflections from Si powder in the transmission geometry employing the Ge(111) crystal analyzer. A wide temperature range (32-900 K), which is controlled by a He/N(2) gas stream system, is available. 288 structure parameters of a zeolite ZSM-5 sample have been demonstrated to successfully refine with a R(wp) value of 6.96% by a Rietveld analysis of the high-resolution powder diffraction data from a 1 mm-diameter capillary specimen.

Crystallization↗
PubMed1997

Spectrum of diurnal rhythms in glomerular permeability in patients with membranous nephropathy.

BACKGROUND: Diurnal rhythms in proteinuria and selectivity index (SI) of proteinuria can vary from patient to patient with respect to phase and amplitude (A/M) and in some cases rhythms are absent. The aim of the present study was to relate this variability to a different pattern of diurnal rhythms in permselectivity of the glomerular capillary wall (GCW). METHODS: Ten patients with nephrotic syndrome due to membranous nephropathy were studied. Diurnal rhythmicity in size-dependent permselectivity of the GCW was determined by measuring 3-h fractional clearances of dextrans (30-90 A) over a period of 1 day. RESULTS: Four types of rhythmicity could be recognized. Type I and II only differed in the magnitude of the diurnal variability in glomerular transport through large pores (r2) and shunt pathway (omega). Both had normal rhythms in clearance of proteins and SI, but all rhythms were more pronounced in the patients with normal renal function and mild histological abnormalities (type II). Although type III also had a normal GFR and minor histological lesions, only transport through omega (and not through r2) showed a significant diurnal rhythm, which implied that this type did not have a normal rhythm in SI. The patients with advanced renal failure and extensive interstitial lesions neither had a rhythm in permselectivity nor had normal rhythms for proteinuria and SI (type IV). CONCLUSIONS: The type of rhythmicity in glomerular permeability corresponds well with the presence and phase of rhythms in clearance of proteins and in SI of the proteinuria.

Adult↗
PubMed2000

Molecular recognition and response in pollen and pistil interactions.

Many bisexual flowering plants possess a reproductive strategy called self-incompatibility (SI) that enables the female tissue (the pistil) to reject self but accept non-self pollen for fertilization. Three different SI mechanisms are discussed, each controlled by two separate, highly polymorphic genes at the S-locus. For the Solanaceae and Papaveraceae types, the genes controlling female function in SI, the S-RNase gene and the S-gene, respectively, have been identified. For the Brassicaceae type, the gene controlling male function, SCR/SP11, and the gene controlling female function, SRK, have been identified. The S-RNase based mechanism involves degradation of RNA of self-pollen tubes; the S-protein based mechanism involves a signal transduction cascade in pollen, including a transient rise in [Ca(2+)]i and subsequent protein phosphorylation/dephosphorylation; and the SRK (a receptor kinase) based mechanism involves interaction of a pollen ligand, SCR/SP11, with SRK, followed by a signal transduction cascade in the stigmatic surface cell.

Brassicaceae↗
PubMed1998

Efficient inhibition of both syncytium-inducing and non-syncytium-inducing wild-type HIV-1 by lamivudine in vivo.

OBJECTIVE: To determine the effect of lamivudine (3TC) on syncytium-inducing (SI) and non-SI (NSI) HIV-1 populations in vivo. DESIGN: Responses in virus load and 3TC resistance in 40 3TC-treated subjects were analysed in relation to the presence or absence of SI HIV-1 variants. METHODS: Peripheral blood samples were collected at regular intervals from 40 HIV-1-infected subjects during 3TC treatment. Virus isolates obtained at the start of treatment were typed for SI-capacity by coculture with MT-2 cells. Changes in levels of viral RNA in plasma were determined by quantitative reverse transcriptase PCR. The relative amount of wild-type and mutant virus at codon 184, associated with HIV resistance to 3TC, was determined using a primer-guided nucleotide incorporation assay after amplification of part of the reverse transcriptase gene. In five subjects the frequency of productively infected CD4+ cells with SI or NSI variants was determined in relation to codon 184 genotype. RESULTS: Twenty-six subjects harboured only NSI variants at baseline, whereas 14 subjects also harboured SI variants. Although baseline plasma viral RNA load and CD4 cell counts were different between the two groups, no differences in the response to 3TC therapy were observed for these parameters. In-depth analysis of five subjects showed that the kinetics of virus load changes and emergence of 3TC resistance mutations were similar in plasma and cells, and comparable for the SI and NSI populations present in one individual. CONCLUSIONS: These data show that, in contrast to didanosine and zidovudine, the pressure exerted by 3TC is similar for SI and NSI M184 populations.

Anti-HIV Agents↗
PubMed2004

Selection in context: patterns of natural selection in the glycoprotein 120 region of human immunodeficiency virus 1 within infected individuals.

Evolution of the HIV-1 V3 loop was monitored in 15 subjects over a period of 5 years at approximately 6-month intervals. Putative recombination was detected in many of the sequences. Evolutionary trees were estimated from the nonrecombinant viral sequences found in each individual. Selection and altered demographic regimes were detected with logit and other contingency analyses in a highly context-dependent fashion. Mutations leading to amino acid substitutions are subject to positive selection over a broad range of clinical conditions in the nonsyncytium-inducing (NSI) form, and the growth rates of the NSI strains and their level of genetic subdivision change little in going from a healthy immune system to a severely compromised immune system. In contrast, the SI form has a significant increase in growth rate as the immune system goes from healthy to compromised, particularly in those subjects who did not receive any antiviral drug therapy. This increase in SI growth rate results in a significant growth advantage of SI over NSI when the immune system is compromised. The SI strains also show more demographic subdivision when the immune system is healthy than when the immune system is compromised, and the SI form has greater demographic subdivision than NSI in subjects with healthy immune systems who also are not receiving antiviral drug therapy. Positive selection on amino-acid-changing mutations weakens and then intensifies again in the SI strains in going from healthy to compromised immune systems. These patterns are consistent with other studies that suggest that NSI strains inhibit replication of SI strains, that the V3 loop is more hidden from the immune system in the NSI form, that evolution in the V3 loop influences cell tropism and coreceptor usage, that substrate for replication of SI forms increases as the disease progresses, and that death of CD8 cells is influenced by the type of coreceptor usage typically found in SI but not in NSI strains. Finally, the transition between NSI and SI forms is associated with a burst of evolutionary change due to strong positive selection at sites other than those that define the NSI/SI phenotypes.

Acquired Immunodeficiency Syndrome↗
PubMed2003

CD14 monocyte receptor, involved in the inflammatory cascade, and insulin sensitivity.

Soluble CD14 (sCD14), detectable at high concentrations constitutively present in the circulation, plays a key role in the neutralization of lipopolysaccharide, one of the most potent biologic response modifiers currently recognized and involved in the regulation of the inflammatory cascade. We tested whether circulating sCD14 was linked to inflammatory parameters and to insulin resistance in apparently healthy subjects. Serum sCD14 concentration did not significantly correlate with body mass index (BMI), waist to hip ratio, systolic or diastolic blood pressure, serum glucose, fasting insulin, fasting insulin resistance index [homeostasis model assessment (HOMA)], or serum uric acid among 123 subjects. The association between sCD14 and fasting insulin (r = -0.19, P = 0.08) and between sCD14 and HOMA (r = -0.21, P = 0.06) tended toward statistical significance among men. Unexpectedly, sCD14 correlated positively with fasting triglycerides (TG) in all the subjects (r = 0.22, P = 0.014), and this association was most significant in men (r = 0.34, P = 0.002). After controlling for TG, the relationships between sCD14 levels and fasting insulin (r = -0.25, P = 0.029), HOMA (r = -0.28, P = 0.014), and uric acid (r = -0.30, P = 0.006) were significant in men. Among nonsmoking men (n = 44), sCD14 significantly correlated with waist diameter (r = -0.30, P = 0.03), diastolic blood pressure (r = -0.34, P = 0.022), and HOMA (r = -0.30, P = 0.03). In a multiple linear regression analysis, BMI (P < 0.00001), TG (P = 0.003), and sCD14 (P = 0.04) (but not age, sex, waist, or smoking status) independently contributed to 26% of HOMA variance. A polymorphism of the CD14 gene, a C-to-T transition at bp -159 from the major transcription start site, seems to play a significant role in regulating serum sCD14 levels. In a subsample of 33 healthy subjects, carriers of the T allele were similar (in age, sex, BMI, fat mass, waist to hip ratio, blood pressure, and fasting glucose and insulin levels) to C/C homozygotes. In the former, integrated area under the curve for serum glucose concentrations after an oral glucose tolerance test was significantly lower (P = 0.02), and insulin sensitivity (SI) index (minimal model analysis) significantly higher (P = 0.036), than in C/C homozygotes. Among 32 type 2 diabetic subjects, carriers of the T allele also showed a significantly higher SI index (P = 0.03) and had significantly lower C-reactive protein (P = 0.03) and lower circulating soluble intercellular adhesion molecule-1 concentrations (P = 0.01) than did C/C homozygotes. To our knowledge, this is the first study to suggest an effect of a genetic polymorphism on both SI (healthy subjects and type 2 diabetic patients) and endothelial dysfunction (sICAM-1 levels) in type 2 diabetes mellitus.

Adult↗
PubMed2004

Control of molecular topology and metal nuclearity in multimetallic assemblies: designer metallosiloxanes derived from silanetriols.

Lipophilic N-bonded silanetriol RSi(OH)(3) (R=(2,6-iPr(2)C(6)H(3))N(SiMe(3))) can be utilized as an effective synthon for building a variety of multimetallic assemblies containing the Si-O-M motif. The type of metallosiloxane synthesized-its nuclearity and its molecular topology-can be readily modulated by the choice of the metal substrate, reaction stoichiometry, and reaction conditions. It is anticipated that the synthetic principles elaborated here will allow the design of many other multifunctional synthons.

Journal Article↗
PubMed2003

Alkyl monolayer passivated metal-semiconductor diodes: 2: Comparison with native silicon oxide.

To understand the electrical properties at passivated metal-semiconductor interfaces, two types of mercury-insulator-silicon (n-type) junctions, Hg\C10H21-Si and Hg\SiO2-Si, were fabricated and their current-voltage and capacitance-voltage characteristics compared. Both of them exhibited near-ideal rectifying characteristics with an excellent saturation current at reverse bias, which is in contrast to the previously reported ohmic behavior of an unmodified mercury-silicon junction. The experimental results also indicated that the n-decyl monolayer passivated junction possesses a higher effective barrier height, a lower ideality factor (that is, closer to unity), and better reproducibility than that of native silicon oxide. In addition, the dopant density and build-in potential, extracted from capacitance-voltage measurements of these passivated mercury-silicon junctions, revealed that alkyl monolayer derivatization does not alter the intrinsic properties of the silicon substrate. The calculated surface state density at the alkyl monolayer\silicon interface is lower than that of the silicon oxide\silicon interface. The present study increases the possibility of using advanced organic materials as ultrathin insulator layers for miniaturized, silicon-based microelectronic devices.

Journal Article↗
PubMed2004

Knockdown of C-terminal Src kinase by siRNA-mediated RNA interference augments T cell receptor signaling in mature T cells.

C-terminal Src kinase (Csk) controls the Src family kinase Lck, which is essential for T cell antigen receptor (TCR)-mediated signaling. For the first time, we here report the effects of acute elimination of Csk in Jurkat T cells and primary T cells using short interfering (si) RNA. In both cell types, 70-85% knockdown of Csk was achieved within 48 h. No alterations in surface expression of CD3, CD4 or CD8, or in Lck protein level were observed. Phosphorylation of Y505 in Lck was markedly reduced and a concomitant 4-5-fold increase in Lck Y394 phosphorylation was observed both in normal and Jurkat T cells. Kinase assays revealed 2-3-fold higher Lck activity. In Jurkat cells, basal levels of zeta chain phosphorylation were elevated, and spontaneous NFAT-AP-1 activation occurred, indicating aberrant Lck kinase activity. After TCR triggering, Csk knockdown cells revealed faster and stronger, but not sustained, phosphorylation of Lck Y394 and zeta chains compared to control. TCR-induced activation of NFAT-AP-1 and TCR/CD28-stimulated IL-2 secretion occurred at weaker stimuli and with augmented responses in Csk knockdown Jurkat and primary T cells, respectively. Altogether, these data suggest that acute elimination of Csk in T cells without evolution of compensatory mechanisms results in aberrant Lck activity and augmented TCR-stimulated responses.

CSK Tyrosine-Protein Kinase↗
PubMed1975

Barbiturate spindle activity in functionally corresponding thalamic and cortical somato-sensory areas in the cat.

(1) Spontaneous barbiturate spindles were recorded from a locus in the thalamic nucleus ventralis postero-lateralis (VPL) and the corresponding projection area in the somato-sensory cortex (SI) in the cat. (2) Type I spindles32 recorded from such sites in the thalamus and cortex, regarded as being functionally on line, were cross-correlated. The analysis gave high negative cross-correlation coefficients, indicating that a considerable degree of wave synchrony existed between the spindles. Maximal wave synchrony was present in the first and middle part of the spindle. (3) The thalamo-cortical spindle wave synchrony was reduced by a small displacement of the cortical electrode within the somato-sensory cortex. Starting with a very lightly anaesthetized animal, small amounts of barbiturate did not influence the size of the cortical area which had spindles in synchrony with the thalamic spindles. (4) Spindles recorded from a VPL locus and from its cortical projection site started simultaneously. When the thalamic and cortical electrodes were positioned functionally off line this spindle coincidence decreased. The intervals between the spindle onsets increased with increasing off line positions of the electrodes. Those few thalamic and cortical spindles which occurred simultaneously showed no, or only weak, spindle wave synchrony. (5) These data suggest a point-to-point topographical relation between thalamic and cortical loci engaged in barbiturate spindle activity. (6) Type I and type II spindles32 differed with respect to spindle characteristics (amplitude, duration, incidence) and also with respect to corresponding thalamic rhythmic activity. These spindle types are, therefore, probably produced by different mechanisms. We suggest that type II spindles represent a purely cortical process initiated by type I spindles.

Animals↗
PubMed1994

Differential phasic modulation of short and long latency afferent sensory transmission to single neurons in the primary somatosensory cortex in behaving rats.

Single neurons were recorded in the forepaw area of the primary somatosensory (SI) cortex of awake rats during rest and running behavior. Locomotor step cycle dependent changes of the transmission of the short (4.5 +/- 0.1-10.5 +/- 0.1 ms, SEURs) and the long (10.6 +/- 0.6-28.5 +/- 2.3 ms, LEURs) latency evoked unit responses were tested by generating post-stimulus time histograms of these neurons' responses to stimulation through electrodes chronically implanted under the skin of the forepaw. Times of footfall were determined by way of frame-by-frame analyses of video recordings, and peri-footfall histograms were generated to differentiate a total of 55 SI cortical neurons into two types: footfall responsive (n = 37) and footfall unresponsive (n = 18) neurons. Peri-footfall gating patterns were determined for both types of cells. The SEURs and the LEURs showed significantly different phasic sensory modulation patterns. A major difference in sensory modulations between footfall responsive and footfall unresponsive cells was noted during the swing phase of the locomotor step cycle. In footfall responsive cells, the SEURs were suppressed most strongly just after footfall, while the LEURs were phasically suppressed following both footfall and footoff. The SEURs were disinhibited during the swing phase. In footfall unresponsive cells, the SEURs were tonically suppressed during the whole locomotor step cycle phases. However, the LEURs were phasically facilitated during the early swing phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed2005

Common cortical network for first and second pain.

We measured, with whole-scalp magnetoencephalography, evoked fields from 10 healthy subjects to 1-ms thulium-laser stimuli that selectively activated nociceptive nerve fibers. The stimuli were delivered to the dorsum of the subject's left hand. The earliest cortical responses peaked at 165 +/- 7 ms, agreeing with the conduction velocity of Adelta-fibers. To stimulate unmyelinated C-fibers, we modified the method of Bragard et al. [Bragard, D., Chen, A.C., Plaghki, L., 1996. Direct isolation of ultra-late (C-fibre) evoked brain potentials by CO2 laser stimulation of tiny cutaneous surface areas in man. Neurosci. Lett. 209, 81-84], by decreasing the total energy of the laser beam and by restricting the size of the stimulated skin area to 0.2-0.3 mm2. The earliest cortical responses to these stimuli peaked at 811 +/- 14 ms. Bilateral activation of the SII cortices was detected in all 10 subjects to Adelta and in 8 subjects to C stimuli, emphasizing the importance of the SII cortex in processing of pain. Additional activation was observed in the posterior parietal cortex (PPC), probably related to sensorimotor coordination targeted to produce precise motor acts that reduce or prevent the pain; the PPC activation may have been accentuated by the required continuous evaluation of the perceived pain. In contrast to some earlier studies, we did not observe activation of the primary somatosensory cortex (SI). Additional activations to both types of stimuli were detected in the cingulate cortex (three subjects) and in the bilateral insular cortex (two subjects). These results implicate that the nociceptive inputs mediated by the Adelta- and C-fibers are processed in a common cortical network in different time windows. Reliable temporospatial characterization of cortical responses to first and second pain offers a unique tool for basic and clinical neuroscience to study the two distinctive pain fiber systems at cortical level.

Adult↗
PubMed1997

Semi-conductor detectors in output factor measurements.

BACKGROUND AND PURPOSE: Output factors are generally measured with cylindrical ionization chambers. It was investigated if Si-diodes of p-type instead could be used. The advantage would be the small detector size and the robust construction of the detector. MATERIALS AND METHODS: Two types of diodes were studied, one with a shielding layer of tungsten specially made to reduce the excess response for scattered photons and one standard diode without any extra shielding. The measurements were performed at accelerating potentials between 4 and 50 MV and beam sizes between 4 cm x 4 cm and 40 cm x 40 cm. RESULTS: The results showed that both types of diodes are suitable for measurements of head scatter factors in mini-phantoms. However, the diodes were found inappropriate for measurement of output factors for large fields in extended water phantoms. For small fields (<10 cm x 10 cm) a small detector is advantageous and no errors due to the scatter contribution were seen. CONCLUSIONS: An cylindrical ionization chamber is the best choice for output factor measurements in extended water phantoms for large field sizes while diodes are an alternative in small fields. There were negligible differences between the detectors in head scatter measurements in mini phantoms.

Humans↗
PubMed2004

The 1,4-diphosphabuta-1,3-diene ligand for coordination of divalent group 13 and 14 elements: a density functional study.

The 1,4-diphosphabuta-1,3-diene (DPB) ligand as a tool for stabilizing anionic group 13 (B, Al, Ga) and neutral group 14 (C, Si, Ge) cyclic Arduengo-type carbenes is studied by quantum chemical calculations at density functional level. Accordingly, for the former group this ligand is better suited than the corresponding 1,4-diazabuta-1,3-diene (DAB) ligand. It results in larger electron affinities for the corresponding doublet states. For the latter group the DPB ligand yields essentially smaller singlet-triplet separations than the DAB ligand. An exception is the anionic boron compound with relative low singlet stability for both the DAB and DPB ligands.

Journal Article↗
PubMed2006

Characterization of molecular linkages placed between zeolite microcrystal monolayers and a substrate with X-ray reflectivity.

We prepared silicalite-1 microcrystal (MC) monolayers on a Si wafer using two different types of molecular linkages, namely, through chloropropyl (CP) groups and through CP/polyethylene imine/CP groups. Whereas the scanning electron microscope images of the two MC monolayers look very much alike but hardly give any information on the nature of molecular linkage between the monolayers and the substrate, their reflectivity curves are distinctively different, despite the fact that the thicknesses of the molecular linkage layers ( approximately 10-20 A) are negligibly small compared to the thicknesses of MC monolayers, ( approximately 3200 A). On the basis of the atomic force microscopic images of the MC surfaces, a rough surface layer with the thickness of approximately 160 A was introduced onto the surface of each MC to conduct a meaningful simulation of the curves with the recursive Parratt formalism. The obtained thickness, roughness, and density of each layer were reasonable, indicating that X-ray reflectivity is a very useful tool for the characterization of very thin layers of molecular linkages existing between much thicker MC monolayers and the substrate.

Microscopy, Electron, Scanning↗
PubMed1998

Neurological disorders during HIV-1 infection correlate with viral load in cerebrospinal fluid but not with virus phenotype.

OBJECTIVES: To verify the compartmentalization of HIV-1 within the central nervous system (CNS) and to define whether viral phenotype of HIV-1 isolates from cerebrospinal fluid (CSF) samples and CSF viral load correlate with the presence and type of neurological disorders. METHODS: A total of 33 HIV-1-infected patients with and without neurological disorders were included in the study. HIV-1 isolation from paired CSF and peripheral blood mononuclear cell (PBMC) samples was attempted by a standard cocultivation technique; the biological phenotype of HIV-1 isolates was assessed by the MT-2 cell assay. CSF and plasma HIV-RNA levels were measured by a quantitative reverse transcripase-polymerase chain reaction. RESULTS: The rate of HIV-1 isolation from CSF and PBMC was 66% (22 isolates) and 85% (28 isolates), respectively. Seventeen out of 22 (77%) CSF HIV-1 isolates were characterized as non-syncytium-inducing, and 15 out of 28 (68%) isolates from PBMC were typed as syncytium-inducing (SI). The presence of SI isolates in CSF was limited to patients with HIV-1-, cytomegalovirus- or JC virus-related disorders and was often associated with high levels of HIV-1 RNA in the CSF. DISCUSSION: Our results demonstrate a correlation between high levels of HIV RNA in CSF and the presence of neurological disorders thus indicating a possible role for HIV-1 RNA in the CSF as a biological marker of neurological disease. The finding of viruses with a different phenotype in paired CSF and PBMC indicates that HIV-1 may evolve differently in the brain and in the blood. This suggests compartmentalization of HIV-1 within the CNS.

CD4 Lymphocyte Count↗