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PubMedDate not supplied

Aortic valve replacement with the Unique Suture Line Stentless USL porcine valve: A new, simple, and safe stentless valve implantation technique.

The Stentless USL, Unique Suture Line porcine valve, is a stentless bioprosthesis developed following the advantages of the studies of the physiology of the aortic root as a functional unit. The direct suturing of the porcine tissue on the soft and elastic tissue of the host's aortic annulus and root gives the bioprosthesis the possibility to follow the physiological movements of the natural valve during the cardiac cycle. For the same reason, there is decreased stress on the valve tissue, especially at the commissural level. There is less technical demand for surgeons who have limited experience with the freehand or miniroot technique due to the limited availability of the homografts because the Stentless USL valve can be implanted with the same technique used with a conventional stented valve. The implant technique used for the Stentless USL valve has advantages, especially in the small aortic calcified annulus in elderly patients where the freehand technique can be difficult and the second suture line can be dangerous (i.e., coronary ostium near the aortic ring or in calcified aortic wall). Our experience with this stentless valve in approximately 200 patients (> 70 years old) shows it to have excellent hemodynamic results even in small valve sizes. The use of this valve and the simple implantation technique avoids the need for complicated aortic root enlargement procedures.

Aged↗
PubMed2005

Physiological implications of trehalase from Phaseolus vulgaris root nodules: partial purification and characterization.

The purification and characterization of trehalase from common bean nodules as well as the role of this enzyme on growth, nodulation nitrogen fixation by examining the effects of the trehalase inhibitor validamycin A, was studied. Validamycin A did not affect plant and nodule mass, neither root trehalase and nitrogenase activity; however this treatment applied at the time of sowing increased nodule number about 16% and decreased nodule trehalase activity (16-fold) and the size of nodules. These results suggest that nodule trehalase activity of Phaseolus vulgaris could be involved in nodule formation and development. In addition, acid trehalase (EC 3.2.1.28) was purified from root nodules by fractionating ammonium sulfate, column chromatography on DEAE-sepharose and sephacryl S-300, and finally on native polyacrylamide gel electrophoresis. The purified homogeneous preparation of native acid trehalase exhibited a molecular mass of 42 and 45 kDa on SDS-PAGE. The enzyme has the optimum pH 3.9, Km of 0.109 mM, Vmax of 3630 nkat mg-1 protein and is relatively heat stable. Besides trehalose, it shows maximal activity with sucrose and maltose and, to a lesser degree melibiose, cellobiose and raffinose, and it does not hydrolyze on lactose and turanose. Acid trehalase was activated by Na+, Mn2+, Mg2+, Li+, Co2+, K+ and inhibited by Fe3+, Hg+ and EDTA.

Cations↗
PubMed1992

Physiology and morphology of Douglas-fir rooted cuttings compared to seedlings and transplants.

Cuttings of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) from three open-pollinated families were rooted in two types of tray, and then grown for 1.5 years in a bareroot nursery. During their second winter they were sampled periodically and tested for cold hardiness, dormancy status, root growth potential and various morphological characteristics. Two-year-old seedlings and transplants were tested concurrently for comparison. Rooted cuttings, seedlings and transplants cold hardened at similar rates during early winter, achieving the same level of midwinter hardiness (LT(50) = -18 degrees C) in early January. However, rooted cuttings remained hardier later into the spring than did seedlings or transplants. Rooted cuttings exhibited deeper dormancy in early winter than seedlings or transplants but these differences disappeared after January. Root growth potentials of all three stock types remained above threshold values established for transplants throughout winter. Rooted cuttings had greater stem diameter, higher stem diameter to height ratio, and greater root weight than either seedlings or transplants. This may reflect lower growing densities for the rooted cuttings. Root/shoot ratios of rooted cuttings were greater than for seedlings and similar to those of transplants. Rooted cuttings also had deeper and coarser root systems, which probably reflects lack of wrenching at the nursery.

Journal Article↗
PubMed2003

Transcriptional changes in response to arbuscular mycorrhiza development in the model plant Medicago truncatula.

Significant changes in root morphology and physiology during arbuscular mycorrhiza (AM) development are likely to be controlled by specific gene expression pattern in the host plant. Until now, little was known about transcriptional changes which occur AM-exclusively; that is, they do not occur during other root-microbe associations, nor are they induced by improved phosphate nutrition. In order to identify such AM-exclusive gene inductions of Medicago truncatula, we used a pool of different RNA samples as subtractor population in a suppressive subtractive hybridization (SSH) experiment. This approach resulted in the identification of a number of new AM-regulated genes. None of these genes were expressed in nonmycorrhiza roots or leaves. Electronic data obtained by comparison of the cDNA sequences to expressed sequence tag (EST) sequences from a wide range of cDNA libraries in the M. truncatula EST database (Gene Index, MtGI) support the mycorrhiza specificity of the corresponding genes, because sequences in the MtGI that were found to match the identified SSH-cDNA sequences originated exclusively from AM cDNA libraries. The promoter of one of those genes, MtGst1, showing similarities to plant glutathione-S-transferase (GST) encoding genes, was cloned and used in reporter gene studies. In contrast to studies with the potato GST gene PRP, MtGst 1 promoter activity was detected in all zones of the root cortex colonized by Glomus intraradices, but nowhere else.

Base Sequence↗
PubMed1986

Changes in excitability induced by herpes simplex viruses in rat dorsal root ganglion neurons.

The physiological properties of rat sensory neurons infected with herpes simplex type 1 viruses and maintained in cell culture were studied using intracellular recording techniques. Two syncytial (cell fusing) and two nonsyncytial strains of virus were examined; individual strains of virus had different effects on neuronal excitability. The nonsyncytial viruses caused a loss of tetrodotoxin-sensitive low-threshold action potentials and blocked hyperpolarization-activated inward rectification, but did not alter the resting membrane potential, depolarization-activated outward rectification, or render the cells leaky. These effects develop progressively over the period 5-15 hr postinfection. One syncytial strain of virus induced spontaneous electrical activity that appeared to be the result of discrete electrical coupling between sensory neuron processes; as a result, action potential discharge is synchronized in coupled neurons. A second syncytial strain of virus rendered neurons inexcitable; however, in these experiments the input resistance fell to low values, possibly as a result of extensive coupling between sensory neurons. Viral replication in sensory neurons was demonstrable with indirect immunofluorescence using an antibody to herpes simplex viruses and correlated with the onset of virally induced changes in excitability. Virally triggered changes in excitability were blocked by the specific herpes virus antimetabolite acyclovir, suggesting that viral adsorption and penetration are by themselves insufficient to evoke changes in excitability. These results suggest that herpes viruses have selective effects on the excitable mechanisms in sensory neurons that are not simply the result of a general loss of membrane conductances or the disruption of transmembrane ion gradients.

Action Potentials↗
PubMed2001

Characterization and application of plant hairy roots endowed with photosynthetic functions.

The scope of this review includes the physiological properties of the hairy roots induced by light irradiation and the kinetic analysis considering the effects of light intensity on hairy root cultures. The cell lines of photomixotrophic and photoautotrophic hairy roots of pak-bung are established from heterotrophic ones by improving the photosynthetic ability of hairy roots through acclimation cultures under light irradiation. Comparisons of physiological properties of derived photoautotrophic cell line with photomixotrophic and heterotrophic ones are also made through histological examination. Moreover, the effect of photosynthesis inhibitor on the photoautotrophic growth of the hairy roots is described. By elucidating the influences of light intensity on growth and chlorophyll formation of photoautotrophic and photomixotrophic hairy roots, a kinetic model was applied to describe the hairy root growth and chlorophyll formation of these cell lines of hairy roots.

Cell Culture Techniques↗
PubMed2003

Vitality of tree fine roots: reevaluation of the tetrazolium test.

Reduction of triphenyltetrazolium chloride (TTC) by tissue to the red-colored insoluble triphenylformazan (TF) is directly linked to the activity of the mitochondrial respiratory chain. Thus, only living tissues should reduce TTC to TF. However, TF production can be detected when the TTC test is applied to control tissues boiled in water. This artifact is mainly the result of the hot ethanol extraction step, which is used to disintegrate the cells and solubilize the TF. We observed that cell wall materials such as cellulose and pectin interact with TTC at temperatures above 60 degrees C, reducing the TTC to TF. By replacing the hot ethanol extraction step with an extraction procedure that involved grinding the boiled tissues and extracting the TF with ethanol at room temperature, the formation of TF was almost entirely eliminated. Application of the modified TTC assay to fine roots of Norway spruce from forest topsoil indicated that the extent of TTC reduction was related to root morphological class as: white fine roots > brown fine roots > black fine roots > boiled fine roots, corresponding to formation of 10.8, 6.1, 0.2 and 0.1 mM TFg(-1)DW, respectively. No significant differences in TTC reduction were recorded between fresh and frozen tissues (frozen in liquid N2) for any fine root class. Application of the modified TTC assay to seedling roots stressed either by drying or by exposure to the toxic metals Cd or Al resulted in significant decreases in TF formation that were related to both the duration of stress and the concentrations of toxic substances, indicating that the modified TTC assay can be used to assess the physiological condition of roots.

Ethanol↗
PubMed1986

Spinal entry route for ventral root afferent fibers in the cat.

Twelve anesthetized and paralyzed cats were used to study the spinal entry routes of ventral root afferent fibers. In all animals, the spinal cord was transected at two different levels, L5 and S2. The L5 through S2 dorsal roots were cut bilaterally, making spinal cord segments L5-S2 neurally isolated from the body except for the L5-S2 ventral roots. From this preparation, a powerful excitation of the discharge rate of motor neurons and dorsal horn cells within the isolated spinal segments was observed after intraarterial injection of bradykinin (50 micrograms in 0.5 ml saline). This excitation of the spinal neurons can be considered the most convincing evidence of the potential physiologic role of the ventral root afferent fibers entering the spinal cord directly through the ventral root, because the apparent route of neuronal input from the periphery is through the ventral roots. However, additional control experiments conducted in the present study showed that the excitation persisted even after cutting all ventral roots within the isolated spinal segments, indicating that excitation was not mediated by the ventral roots. Furthermore, direct application of bradykinin on the dorsal surface of the spinal cord also increased the motoneuronal discharge rate, suggesting that excitation of spinal neurons produced by intraarterial injection of bradykinin is due to a direct action of bradykinin on the spinal cord. Thus, we provided an alternate explanation for the most convincing evidence indicating that physiologically important ventral root afferent fibers enter the spinal cord directly through the ventral root. Based on existing experimental evidence, it is likely that the majority of physiologically active ventral root afferent fibers travel distally toward the dorsal root ganglion and then enter the spinal cord through the dorsal root.

Action Potentials↗
PubMed2005

Female sexual dysfunction: principles of diagnosis and therapy.

Female sexual dysfunction is a common health problem, affecting approximately 43% of women. Female sexual dysfunction is defined as disorders of libido, arousal, orgasm, and sexual pain that lead to personal distress or interpersonal difficulties. It is frequently multifactorial in etiology, with physiological and psychologic roots. Approaching female sexual dysfunction involves an open discussion with the patient, followed by a thorough physical examination and laboratory testing. Therapy consists of patient and partner education, behavior modification, and may include individualized pharmacotherapy. Ultimately, as awareness and research in the field grows, it is hoped that a better understanding of the physiology and pharmacology of the female sexual response will be achieved.

Androgens↗
PubMed1993

Emerging relationships between cytochemical properties and sensory modality transmission in primary sensory neurons.

Primary sensory neurons have been categorized according to a variety of characteristics, including modality responsiveness, somal size, cytology, cytochemistry, and the organization of their central axon collateral arborizations. A major aim in the study of primary afferents has been to determine the relationships between dorsal root ganglia neuronal physiology, anatomy, and chemistry that could provide a basis for a classification scheme more directly relevant to function. Here we briefly review these relationships and examine the utility of specific histochemical and immunohistochemical markers representative of distinct populations of neurons that may transmit particular sensory modalities. In addition, we discuss some of our observations suggesting that one population of dorsal root ganglia neurons contains high levels of cytochrome oxidase, carbonic anhydrase, parvalbumin, and calbindin D28k, while a separate population contains fluoride-resistant acid phosphatase, calcitonin gene-related peptide, and displays immunoreactivity with an antibody that labels the central arborization of a specific class of unmyelinated afferents in the dorsal horn. This may have implications for the combinations of substances contained within neurons with distinct sensory functions.

Animals↗
PubMed1995

The transketolase gene family of the resurrection plant Craterostigma plantagineum: differential expression during the rehydration phase.

Transketolases, key enzymes of the reductive and oxidative pentose phosphate pathways, are responsible for the synthesis of sugar phosphate intermediates. Here we report the first molecular analysis of transketolase genes from plants. Three distinct classes of transketolase-encoding cDNA clones were isolated from the desiccation-tolerant resurrection plant Craterostigma plantagineum. One class represented by the transcript tkt3 is constitutively expressed in leaves and roots under all physiological conditions tested. By biochemical analysis and protein sequencing of purified transketolase, it was shown that tkt3 is expressed in three enzymatically active isoforms. An intriguing discovery was that accumulation of the two other transketolase transcripts, tkt7 and tkt10, is preferentially associated with the rehydration process of the desiccated plant; whereas tkt10 is only expressed in leaves, tkt7 was detected in leaves and roots. This observation suggests a possible role for these transketolases in the conversion of sugars, which are a major phenomenon in the rehydration process. Despite an abundant level of tkt7 and tkt10 transcripts in rehydrating leaves, proteins could not be isolated. This is due in part to a translational control mechanism acting on the loading of mRNAs to polysomes.

Adaptation, Biological↗
PubMed1987

The Root effect.

Considering the presently available data it is clear that the Root effect represents an exaggerated alkaline Bohr effect which occurs in the absence of a normal acid Bohr effect and is associated with a loss of oxygen binding capacity at low pH. Undoubtedly at the molecular level the presence of a Ser residue at position F9(94) beta in these haemoglobin is of primary importance. No Root effect haemoglobin has yet been identified which lacks this substitution. On the other hand however many haemoglobins are known which possess this Ser residue and at the same time lack a Root effect. Other factors arising from interactions at other sites in the haemoglobin molecule are obviously sufficient to negate the otherwise stabilizing effect of this critical Ser residue. The loss of cooperativity of Root effect systems as the pH is lowered is readily explained as due to stabilization of the low affinity T state to such a degree that the switch to the high affinity R state is suppressed even in the fully liganded molecule. The observation of Hill coefficients of less than unity requires that within the T state chain heterogeneity exists such that the alpha and beta chain haems demonstrate significantly different affinities for ligand. The physiological role of Root effect haemoglobins is demonstrably not inevitably linked to the swim bladder but more probably arose from the need to oxygenate the poorly vascularized retina of many fishes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Evaluation of decalcified allogenic bone matrix grafts in and around root apices. A histological study.

Decalcified Allogenic Bone grafts were implanted in and around eighteen root apices after apicoectomy. The procedure was carried out on eighteen rabbits, dividing them into three groups of six rabbits each. The animals were sacrificed after 48-72 hours, 8-10 days & 8-10 weeks period of interval. Result of the present investigation reveal that DABM grafts stimulate osteogenesis and cementogenesis after the initial phase of inflammation. Tissues simulating bone and cementum appear at the apical end, speculating that the grafts would certainly result in physiological sealing of root apices. The possibility of saving the life of non vital teeth with or without wide apical foramen will enhance in future.

Animals↗
PubMed1986

A model for the Ca2+-induced conformational transition of troponin C. A trigger for muscle contraction.

The initial contractile event in muscle is the binding of Ca2+ ions to troponin C of the troponin complex, leading to a series of conformational changes in the members of the thin and thick filaments. Knowledge of the crystal structure of turkey skeletal muscle troponin C has provided a structural basis for the modeling of the first stage of this process in atomic detail. This crystal structure probably represents the molecule in the relaxed state of muscle, with two of the maximum of 4 Ca2+ ions bound. The basis for the model presented here is that upon binding of the additional two Ca2+ ions, the regulatory domain of the molecule undergoes a conformational transition to become closely similar in structure to the domain which always binds Ca2+ or Mg2+ under physiological conditions. The root mean square discrepancy in atomic coordinates between the apo and the modeled Ca2+-bound states of the regulatory domain is 4.8 A, with some shifts as large as 10-15 A in the region near the linker between the two Ca2+ binding sites. It is demonstrated that this Ca2+-bound conformation of the regulatory domain conforms to accepted protein structure rules and that the change in conformation can be accomplished without encountering any barriers too high to be surmounted on the physiological time scale.

Amino Acid Sequence↗
PubMed1992

[Division and specialization of the Western European physiology].

The 19th century has been thought to be the turning point that the experimental method began to take strong root as the core to solve many physiological subjects, and the discipline of physiology got firmly fixed as the specialized one in the western Europe. Authors found the following characteristics in the process of the division and specialization of the 19th century western physiology. 1) It was the process of its separation from the discipline of anatomy that was necessary in the development of physiology as the independent, specialized division. Newly grown ideas, that there were working functions specialized study, were the important background and basis of the development of physiology as the specialized discipline. 2) It was not until the force and influence of the metaphysical concept on the living things (vitalism) grew weak that physiology could become the specialized discipline. The new materialistic concept about living things made it possible for the researchers of that time to apply the physico-chemical method in the study of physiological problems. 3) Institutionalization of the physiological research and education accelerated its development and specialization. The followings appeared in the mid-19th century: specialized professorship, division as the separated subject in the undergraduated medical school curriculum, laboratory settings for the purpose of physiological study, establishment of independent academic societies and publication of their own journals. Two main factors, namely, both the settlement of the new physiological thought and method of the very scientific nature and the institutionalization within the academic and medical societies, exerted influences on each other in the ground of the 19th century western Europe. Through that process, the discipline of physiology took root deep as the independent specialized division in the societies of science and medicine.

Europe↗
PubMed1985

Effects of colchicine and hydrocortisone on unimpeded eruption rates of root-resected mandibular incisors of rats.

A single injection of colchicine and daily injections of hydrocortisone have opposite effects on tooth eruption, respectively causing marked reduction and marked increase in unimpeded eruption rates in the root-resected incisors of rats. Unimpeded eruption rates of both root-resected and normal, non-resected, incisors responded identically to these two drugs, providing support for the view that the eruptive process following root resection is physiological. It was not possible to obtain direct evidence relating to either the hydrostatic pressure or the periodontal fibroblast hypotheses of tooth eruption; the drugs used to affect the eruption rates of resected rat incisors could also affect either the tissue hydrostatic pressure or the motility or contractibility of periodontal fibroblasts or both.

Animals↗