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PubMed2004

Labour is associated with increased expression of type-IIA secretory phospholipase A2 but not type-IV cytosolic phospholipase A2 in human myometrium.

Human labour is associated with increased prostaglandin synthesis within the uterus. The aim of this study was to examine the expression of the type-IV cytosolic phospholipase A2 (cPLA2-IV) and the type IIA secretory phospholipase A2 (sPLA2-IIA) in myometrium in association with labour onset at term and preterm deliveries. These enzymes are important for the release of the prostaglandin precursor, arachidonic acid, from phospholipid membrane stores. RT-PCR was used to determine differences in gene expression between non-labour and labour groups. Expression of sPLA2-IIA in human myometrium was significantly increased with pregnancy, and with labour, both at term and preterm. Expression of cPLA2-IV in myometrium was not significantly altered with respect to pregnancy or labour. Immunohistochemical analysis demonstrated differences in the spatial localization of cPLA2-IV and sPLA2-IIA protein in upper and lower segment myometrium. cPLA2-IV was predominantly in vascular endothelial cells, while sPLA2-IIA was observed in vascular, endothelial and smooth muscle cells. In addition, sPLA2-IIA showed a distinct nuclear or perinuclear localization in myometrial smooth muscle cells of the lower segment. We postulate that the increased expression of sPLA2-IIA rather than cPLA2-IV in the myometrium may play a role in the onset and/or maintenance of human parturition.

Adult↗
PubMed2004

Over 20% of human transcripts might form sense-antisense pairs.

The major challenge to identifying natural sense- antisense (SA) transcripts from public databases is how to determine the correct orientation for an expressed sequence, especially an expressed sequence tag sequence. In this study, we established a set of very stringent criteria to identify the correct orientation of each human transcript. We used these orientation-reliable transcripts to create 26 741 transcription clusters in the human genome. Our analysis shows that 22% (5880) of the human transcription clusters form SA pairs, higher than any previous estimates. Our orientation-specific RT-PCR results along with the comparison of experimental data from previous studies confirm that our SA data set is reliable. This study not only demonstrates that our criteria for the prediction of SA transcripts are efficient, but also provides additional convincing data to support the view that antisense transcription is quite pervasive in the human genome. In-depth analyses show that SA transcripts have some significant differences compared with other types of transcripts, with regard to chromosomal distribution and Gene Ontology-annotated categories of physiological roles, functions and spatial localizations of gene products.

Base Pairing↗
PubMed2001

A numerical measure of amino acid residues similarity based on the analysis of their surroundings in natural protein sequences.

A measure of similarity between amino acid residues based on the analysis of the surroundings of each residue in primary structures of native proteins is proposed. The statistical data used for this purpose were obtained from the analysis of 168,808 protein sequences, which comprise the Protein Identification Research database (release 63). Using various threshold values of the proposed measure, amino acid residues were classified into several groups. The classification elaborated differs essentially from groupings previously used. The numerical measure of amino acid residues similarity can be used in site-directed mutagenesis studies for the prediction of probability of local spatial rearrangements in proteins.

Amino Acid Sequence↗
PubMed1999

Quantitative magnetic resonance imaging demonstrates alterations of the lingual musculature in obstructive sleep apnea.

Upper airway musculature is important in the pathogenesis of obstructive sleep apnea. Electromyographic studies of patients with obstructive sleep apnea demonstrate increased activity of upper airway dilator muscles. Biopsy studies of these muscles show both adaptation and muscle injury. In this study we utilized quantitative magnetic resonance imaging to characterize changes in the upper airway musculature of patients with obstructive sleep apnea. This technique provides measurements of the T2 relaxation times of upper airway muscles (genioglossus, geniohyoid, sternohyoid/sternothyroid) spatially localized to submillimeter resolution. Our results demonstrate that the mean T2 values of genioglossus (p = 0.04) and geniohyoid (p = 0.06) differ between the apneic and control groups, while the values for the sternohyoid/sternothyroid muscles (p = 0.6) are similar between groups. In both apneics and normals respectively the T2 values for the genioglossus (p = 0.0003, 0.0001) and geniohyoid (p = 0.0054, 0.001) were significantly greater than for the sternohyoid/sternothyroid muscles. The changes observed are compatible with the hypothesis that there is increased edema and possibly increased fat content of the tongue muscles in patients with obstructive sleep apnea.

Adipose Tissue↗
PubMed2002

Nod factor induction of reactive oxygen species production is correlated with expression of the early nodulin gene rip1 in Medicago truncatula.

Plant genes that are specifically activated by the rhizobial lipochitooligosaccharide signal molecule (Nod factor) in legume hosts are collectively referred to as nodulins. Although nodulin gene expression is both spatially and temporally correlated with symbiosis, the function of these genes and the molecular events underlying their expression remain unknown. Sequence analysis of rip1, an early nodulin gene encoding a putative peroxidase protein, revealed the existence of sequence motifs with homology to reactive oxygen species (ROS) responsive cis elements. Here we report that recognition of compatible Nod factor rapidly stimulates a spatially localized production of reactive oxygen species in legume roots. Sinorhizobium meliloti mutants that produce an altered Nod factor structure and a nonnodulating plant mutant, dmi1-1, that is implicated in Nod factor signal transduction are equally impaired in the ability to elicit ROS production and rip1 expression. Interestingly, both rip1 transcription and ROS production exhibit the same tissue-specific pattern of localization. Moreover, exogenous hydrogen peroxide is sufficient to activate rip1 transcription. Taken together, these results suggest that ROS production is a consequence of specific Nod factor perception and implicate H2O2 produced during this response as a mediator of Nod factor-induced rip1 expression.

Gene Expression Regulation, Developmental↗
PubMed2004

Induction and spatial organization of polyamine biosynthesis during nodule development in Lotus japonicus.

Putrescine and other polyamines are produced by two alternative pathways in plants. One pathway starts with the enzyme arginine decarboxylase (ADC; EC 4.1.1.19), the other with ornithine decarboxylase (ODC; EC 4.1.1.17). Metabolite profiling of nitrogen-fixing Lotus japonicus nodules, using gas chromatography coupled to mass spectrometry, revealed a two- to sixfold increase in putrescine levels in mature nodules compared with other organs. Genes involved in polyamine biosynthesis in L japonicus nodules were identified by isolating cDNA clones encoding ADC (LjADC1) and ODC (LjODC) from a nodule library. Searches of the public expressed sequence tag databases revealed the presence of a second gene encoding ADC (LjADC2). Real-time reverse-transcription-polymerase chain reaction analysis showed that LjADC1 and LjADC2 were expressed throughout the plant, while LjODC transcripts were detected only in nodules and roots. Induction of LjODC and LjADC gene expression during nodule development preceded symbiotic nitrogen fixation. Transcripts accumulation was maximal at 10 days postinfection, when a 6.5-fold increase in the transcript levels of LjODC was observed in comparison with the uninfected roots, while a twofold increase in the transcript levels of LjADC1 and LjADC2 was detected. At later stages of nodule development, transcripts for ADC drastically declined, while in the case of ODC, transcript accumulation was higher than that in roots until after 21 days postinfection. The expression profile of genes involved in putrescine biosynthesis correlated well with the expression patterns of genes involved in cell division and expansion, including a L. japonicus Cyclin D3 and an alpha-expansin gene. Spatial localization of LjODC and LjADC1 gene transcripts in developing nodules revealed that both transcripts were expressed in nodule inner cortical cells and in the central tissue. High levels of LjADC1 transcripts were also observed in both nodule and connecting root vascular tissue, suggesting that putrescine and other polyamines may be subject to long-distance transport. Our results indicate that polyamines are primarily involved in physiological and cellular processes involved in nodule development, rather than in processes that support directly symbiotic nitrogen fixation and assimilation.

Amino Acid Sequence↗
PubMed2003

Gonadotropin-releasing hormone alters the T helper cytokine balance in the pregnant rat.

The interactions between immune-endocrine and reproductive systems are heightened during pregnancy as an adaptive mechanism, and are regulated by a complex array of hormones and cytokines that control the survival of a semiallogeneic conceptus. GnRH can exert direct effects on the immune system via its receptor (GnRH-R) on lymphoid cells. In the present study, we employed in vitro, ex vivo, and in vivo approaches to investigate the role of GnRH in the modulation of T helper cytokines in pregnant rats undergoing termination of pregnancy. Day 8 pregnant rats were infused with a GnRH agonist (GnRH-Ag) for 24 h using an osmotic minipump. Sham control rats were infused with the vehicle, saline. Lymphocytes were isolated from sham and treated rats and polyclonally stimulated with immobilized anti-CD3 antibody. The levels of the signature T helper 1 (Th-1) cytokines (interferon-gamma [IFN-gamma] and interleukin-2 [IL-2]) and Th-2 cytokines (IL-4 and IL-10) were measured in culture supernatants. Using immunoflourescence confocal microscopy, we demonstrated for the first time the spatial localization of GnRH-R protein on the surface of lymphocytes. We observed a marked increase in IFN-gamma and inhibition of IL-4 production from lymphocytes of pregnant rats treated in vitro with different doses of GnRH-Ag. Further, the responsiveness of lymphocytes to produce IFN-gamma was markedly increased in cells cultured ex vivo from GnRH-Ag infused rats, whereas the capacity of lymphocytes to produce IL-4 was significantly inhibited. In addition, GnRH-Ag infusion in pregnant rats induced a shift toward Th-1 cytokines in the serum. We did not observe any significant difference in IL-2 and IL-10 production in response to GnRH-Ag. Our results suggest an additional function for GnRH as a Th-1 inducer and Th-2 inhibitor. GnRH can thus skew the cytokine balance to predominantly Th-1 type in pregnancy, leading to the termination of pregnancy in rats.

Abortifacient Agents↗
PubMed2004

Human myometrial gene expression before and during parturition.

Identification of temporal and spatial changes in myometrial gene expression during parturition may further the understanding of the coordinated regulation of myometrial contractions during parturition. The objective of this study was to compare the gene expression profiles of human fundal myometrium from pregnant women before and after the onset of labor using a functional genomics approach, and to further characterize the spatial and temporal expression patterns of three genes believed to be important in parturition. Fundal myometrial mRNA was isolated from five women in labor and five women not in labor, and analyzed using human UniGEM-V microarrays with 9182 cDNA elements. Real-time polymerase chain reaction using myometrial RNA from pregnant women in labor or not in labor was used to examine mRNA levels for three of the genes; namely, prostaglandin-endoperoxide synthase 2 (PTGS2), calgranulin B (S100A9), and oxytocin receptor (OXTR). The spatial expression pattern of these genes throughout the pregnant uterus before and after labor was also determined. Immunolocalization of cyclooxygenase-2 (also known as PTGS2) and S100A9 within the uterine cervix and myometrium were analyzed by immunohistochemistry. Few genes were differentially expressed in fundal myometrial tissues at term with the onset of labor. However, there appears to be a subset of genes important in the parturition cascade. The cellular properties of S100A9, its spatial localization, and dramatic increase in cervix and myometrium of women in labor suggest that this protein may be very important in the initiation or propagation of human labor.

Calgranulin B↗
PubMed2003

Potential applications of photodynamic therapy in regenerative medicine.

Photodynamic therapy (PDT) is an emerging field that uses light-activated drugs to produce specific biological effects in cells and tissues. Its particular strengths arise from the ability to spatially localize the biological responses by the way the light is applied; the range of possible mechanisms of action at the cell, tissue, and organism levels; and the combination of novel molecular and optical technologies. This paper presents the basic principles of PDT and considers some of the possible applications in regenerative medicine.

Bone Regeneration↗
PubMed1992

Distribution of putative odour receptor proteins in olfactory epithelium.

To investigate immunohistochemically the spatial localization of putative odour receptor proteins, we synthesized a polypeptide which corresponds to a region of a putative odour receptor protein, I3, and raised an antibody to the peptide. In rat olfactory epithelium, the antibody specifically recognized cilia of a small subset of olfactory receptor neurons, suggesting that the odour receptor protein is localized selectively in the cilia. Olfactory receptor neurons having immunoreactive cilia were distributed sparsely throughout the epithelium. This suggests that receptor neurons expressing a similar odour receptor protein are probably distributed similarly in the epithelium.

Amino Acid Sequence↗
PubMed1999

A selective imaging of tinnitus.

We selectively imaged the neural correlates of tinnitus, by contrasting a condition with no phantom auditory sensation with a condition during which tinnitus is present, using a rare form of tinnitus elicited by eye movements. Using positron emission tomography (PET), we demonstrate that phantom auditory sensation increases regional cerebral blood flow bilaterally in temporo-parietal association auditory areas but not in the primary auditory cortex. These results confirm that conscious perception does not necessarily require activation in primary areas and suggest that the perceptual qualities of tinnitus, e.g. intensity, frequency and spatial localization, are represented in temporo-parietal regions. Activation in these regions is compatible with cortical processing of ascending auditory messages generated at subcortical levels.

Adult↗
PubMed2000

Left ventricular myocardial adenosine triphosphate changes during reperfusion of ventricular fibrillation: the influence of flow and epinephrine.

OBJECTIVE: To determine whether epinephrine in combination with high flow worsens left ventricular (LV) myocardial high-energy phosphate stores during reperfusion of ischemic ventricular fibrillation (VF). DESIGN: Blinded, prospective block randomized, placebo controlled study. SETTING: University medical center research laboratory. SUBJECTS: A total of 22 mixed breed swine weighing 22.0+/-3.3 kg (SD). INTERVENTIONS: Open-chest swine, anesthetized with alpha-chloralose, underwent 10 mins of nonperfused VF followed by reperfusion with cardiopulmonary bypass for 90 mins and then defibrillation. Animals were block randomized to four groups for reperfusion: Group 1 (n = 5), high flow (100 mL/kg/min) and epinephrine (2.5 microg/kg/min); Group 2 (n = 5), high flow and placebo; Group 3 (n = 6), low flow (30 mL/kg/min) and epinephrine; and Group 4 (n = 6), low flow and placebo. MEASUREMENTS AND MAIN RESULTS: In vivo LV creatine phosphate (CP) and adenosine triphosphate (ATP) were determined using whole wall and spatially localized 31P NMR spectroscopy at 4.7 Tesla. During perfusion of the fibrillating myocardium, epinephrine significantly increased aortic pressure (p < .05) and improved defibrillation rates (p < .01). ATP levels during reperfusion were significantly decreased within all groups compared with baseline. There were no differences in ATP levels between groups. High flow, independent of epinephrine, was associated with increased preservation of ATP (p < .05), increased CP/ATP ratios (p < .02) in all layers of the LV wall, and decreased aortic and cardiac vein lactates (p < .001). CONCLUSIONS: Epinephrine, in combination with flow higher than standard cardiopulmonary resuscitation flows, increased perfusion pressure and defibrillation rates, but did not significantly alter myocardial ATP during VF reperfusion in the in vivo heart Reperfusion flow, independent of epinephrine, is a critical determinant of myocardial ATP preservation.

Adenosine Triphosphate↗
PubMed1997

Magnetic resonance pulmonary angiography and direct imaging of embolus for the detection of pulmonary emboli.

RATIONALE AND OBJECTIVES: The authors developed a two-dimensional breathhold magnetic resonance (MR) technique for the direct imaging of pulmonary emboli. METHODS: In vitro MR imaging was performed to demonstrate the potential generation of clot-blood contrast by in vivo pulmonary embolism (PE). A two-dimensional magnetization prepared gradient-echo (turbo-FLASH) breathhold technique was designed to directly image intravascular emboli by the selective nulling of the blood signal. A turbo-FLASH pulmonary angiographic breathhold sequence was used to provide spatial localization of detected emboli. Thirteen patients with suspected PE were studied; 6 patients underwent conventional pulmonary angiography (CPA) and the remaining 7 had diagnoses based on findings from other studies. RESULTS: In vitro study of blood clot demonstrated an initial rise and then fall in T1 sufficient to generate clot-blood contrast after eight days of clot formation. All patients with CPA or alternative study evidence of PE were diagnosed as positive with direct embolus imaging MR. There were no false-positive diagnoses. Three additional emboli were detected using the MR technique compared with CPA. The MR pulmonary angiographic sequence provided a useful road map for localization of intravascular emboli but was less sensitive for PE detection than the embolus imaging technique. CONCLUSIONS: The direct imaging of PE is feasible using a simple two-dimensional breathhold technique.

Adult↗
PubMed2000

Early temporal characteristics of cerebral blood flow and deoxyhemoglobin changes during somatosensory stimulation.

The close correspondence between neural activity in the brain and cerebral blood flow (CBF) forms the basis for modern functional neuroimaging methods. Yet, the temporal characteristics of hemodynamic changes induced by neuronal activity are not well understood. Recent optical imaging observations of the time course of deoxyhemoglobin (HbR) and oxyhemoglobin have suggested that increases in oxygen consumption after neuronal activation occur earlier and are more spatially localized than the delayed and more diffuse CBF response. Deoxyhemoglobin can be detected by blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI). In the present study, the temporal characteristics of CBF and BOLD changes elicited by somatosensory stimulation in rat were investigated by high-field (9.4 T) MRI. With use of high-temporal-resolution fMRI, it was found that the onset time of the CBF response in the somatosensory cortex was 0.6 +/- 0.4 seconds (n = 10). The CBF changes occurred significantly earlier than changes in HbR concentration, which responded after 1.1 +/- 0.3 seconds. Furthermore, no early increases in HbR (early negative BOLD signal changes) were observed. These findings argue against the occurrence of an early loss of hemoglobin oxygenation that precedes the rise in CBF and suggest that CBF and oxygen consumption increases may be dynamically coupled in this animal model of neural activation.

Animals↗
PubMed2000

Ca2+ channels, 'quantized' Ca2+ release, and differentiation of myocytes in the cardiovascular system.

The application of confocal microscopy to cardiac and skeletal muscle has resulted in the observation of transient, spatially localized elevations in [Ca2+]i, termed 'Ca2+ sparks'. Ca2+ sparks are thought to represent 'elementary' Ca2+ release events, which arise from one or more ryanodine receptor (RyR) channels in the sarcoplasmic reticulum. In cardiac muscle, Ca2+ sparks appear to be key elements of excitation-contraction coupling, in which the global [Ca2+]i transient is thought to involve the recruitment of Ca2+ sparks, each of which is controlled locally by single coassociated L-type Ca2+ channels. Recently, Ca2+ sparks have been detected in smooth muscle cells of arteries. In this review, we analyse the complex relationship of Ca2+ influx and Ca2+ release with local, subcellular Ca2+ microdomains in light of recent studies on Ca2+ sparks in cardiovascular cells. We performed a comparative analysis of 'elementary' Ca2+ release units in mouse, rat and human arterial smooth muscle cells, using measurements of Ca2+ sparks and plasmalemmal K(Ca) currents activated by Ca2+ sparks (STOCs). Furthermore, the appearance of Ca2+ sparks during ontogeny of arterial smooth muscle is explored. Using intact pressurized arteries, we have investigated whether RyRs causing Ca2+ sparks (but not smaller 'quantized' Ca2+ release events, e.g. hypothetical 'Ca2+ quarks') function as key signals that, through membrane potential and global cytoplasmic [Ca2+], oppose arterial myogenic tone and influence vasorelaxation. We believe that voltage-dependent Ca2+ channels and local RyR-related Ca2+ signals are important in differentiation, proliferation, and gene expression. Our findings suggest that 'elementary' Ca2+ release units may represent novel potent therapeutic targets for regulating function of intact arterial smooth muscle tissue.

Animals↗
PubMed2001

Comparison of frameless stereotactic systems: accuracy, precision, and applications.

OBJECTIVE: Frameless stereotactic systems have become an integral part of neurosurgical practice. At our center, we recently introduced for clinical use a small, portable, frameless stereotactic system, namely the Cygnus PFS system (Compass International, Rochester, MN). The purpose of this study was to compare the accuracy of the Cygnus PFS system with that of two larger systems that are also currently in use at our institution, i.e., the SMN system (Zeiss, Oberkochen, Germany) and the ISG viewing wand (ISG Technologies, Toronto, Canada). These systems represent three kinds of frameless stereotactic technologies that are commercially available. Each system uses a different method of spatial localization, i.e., mechanical linkage (ISG system), magnetic field digitization (Cygnus system), or optical technology (SMN system). METHODS: Using a stereotactic "phantom," we measured the accuracies of all three systems with identical data sets. The errors in localization in three-dimensional space for nine targets were calculated by using 10 magnetic resonance imaging data sets. The precision of each system was also calculated. RESULTS: With this experimental protocol, the Cygnus system attained a mean accuracy of 1.90 +/- 0.7 mm, the ISG viewing wand system a mean accuracy of 1.67 +/-0.43 mm, and the SMN microscope a mean accuracy of 2.61 +/- 0.99 mm. The precision values were not significantly different among the systems. CONCLUSION: We observed only small differences in accuracy and precision among these three systems. We briefly review the advantages and disadvantages of each system and note that other factors, such as portability, ease of use, and microscope integration, should influence the selection of a frameless stereotactic system.

Humans↗
PubMed1995

Visual dysfunction predicts cognitive deficits in Alzheimer's disease.

Deficits in basic visual capacities are prevalent in Alzheimer's disease (AD), raising the question of their impact on cognitive function. We examined the relation between vision and cognition in 72 patients with AD. Vision tests assessed color discrimination, stereoacuity, contrast sensitivity, and backward pattern masking. For cognitive tests of object recognition, at least 25% (up to 50%) of score variance was predicted by performance on a vision test. For tests of spatial localization, only 2 to 11% of the variance was predicted by performance on a vision test. The results indicated that: (1) visual dysfunction was a significant predictor of cognitive dysfunction in AD, and (2) visual deficits in AD may have a strong functional impact on performance in specific cognitive domains.

Aged↗
PubMed2000

A noninvasive anthropometric technique for measuring kyphosis and lordosis: an application for idiopathic scoliosis.

STUDY DESIGN: Cross-sectional measurement of the sagittal geometry of adolescent idiopathic scoliosis patients. OBJECTIVES: To evaluate the accuracy of a noninvasive anthropometric approach for the measurement of kyphosis and lordosis. SUMMARY OF BACKGROUND DATA: Noninvasive approaches were developed to estimate the sagittal curvatures of the spine. However, the magnitude of the estimation error could be high for an important proportion of patients, which leads to a difficult clinical application. METHODS: The group was composed of 124 female patients with a mean age of 13.5 years (SD 2. 7 years) with Cobb angles ranging from 4 degrees to 66 degrees. Kyphosis and lordosis were measured on the lateral radiograph. The spine sagittal curvature of the same patients was also estimated using the spatial localization of skin markers placed overlying the spinous processes. These coordinates served as input into a simple trigonometric model. Data were collected by means of a stereovideographic technique (Motion Analysis Corp., Santa Rosa, CA). RESULTS: The intraclass correlation coefficient between both approaches was 0.94 for kyphosis and 0.91 for lordosis; the mean absolute differences were 5 degrees (SD 4 degrees ) and 6 degrees (SD 6 degrees ), respectively. The difference was less than 10 degrees in 91% of the patients for kyphosis, and in 79% for lordosis. CONCLUSIONS: The proposed technique appears to give more representative results than those presented in the literature. It has the advantage of being part of a global noninvasive postural evaluation. Using this approach in a systematic manner could help reduce radiograph exposure while keeping track of the spine sagittal curvatures.

Adolescent↗