Face selection in addition and elimination in sterically unbiased systems.
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Journal Article↗
Biomedical subjects
W S Chung
Publications and source records attributed to W S Chung.
Involvement of specific calmodulin isoforms in salicylic acid-independent activation of plant disease resistance responses.
The Ca2+ signal is essential for the activation of plant defense responses, but downstream components of the signaling pathway are still poorly defined. Here we demonstrate that specific calmodulin (CaM) isoforms are activated by infection or pathogen-derived elicitors and participate in Ca2+-mediated induction of plant disease resistance responses. Soybean CaM (SCaM)-4 and SCaM-5 genes, which encode for divergent CaM isoforms, were induced within 30 min by a fungal elicitor or pathogen, whereas other SCaM genes encoding highly conserved CaM isoforms did not show such response. This pathogen-triggered induction of these genes specifically depended on the increase of intracellular Ca2+ level. Constitutive expression of SCaM-4 and SCaM-5 in transgenic tobacco plants triggered spontaneous induction of lesions and induces an array of systemic acquired resistance (SAR)-associated genes. Surprisingly, these transgenic plants have normal levels of endogenous salicylic acid (SA). Furthermore, coexpression of nahG gene did not block the induction of SAR-associated genes in these transgenic plants, indicating that SA is not involved in the SAR gene induction mediated by SCaM-4 or SCaM-5. The transgenic plants exhibit enhanced resistance to a wide spectrum of virulent and avirulent pathogens, including bacteria, fungi, and virus. These results suggest that specific CaM isoforms are components of a SA-independent signal transduction chain leading to disease resistance.
Calcium↗
Review of significant microvascular surgical breakthroughs involving the heart and lungs in rats.
Models of transplantation of the heart and lung in the rat have been important in determining the mechanisms of rejection and their treatment. Reviewed here are several important milestones contributing to the current state of the art of clinical heart and lung transplantation.
Anastomosis, Surgical↗
Myeloid differentiation of human cord blood CD34+ cells during ex vivo expansion using thrombopoietin, flt3-ligand and/or granulocyte-colony stimulating factor.
We investigated the phenotypic changes of human umbilical cord blood (CB) CD34+ cells during ex vivo expansion using thrombopoietin (TPO), flt3-ligand (FL), and/or granulocyte-colony stimulating factor (G-CSF). During ex vivo expansion of CD34+ cells isolated from human CB for up to 5 weeks, surface expression of molecules on the cultured cells including CD64 (Fc gammaRI), CD32 (Fc gammaRII), CD16 (Fc gammaRII), CD11b (MAC-1) and CD18 (beta2-integrin) was analysed by flow cytometry along with simultaneous measurement of apoptosis by 7-aminoactinomycin D staining method. CD64, CD32 and/or CD18 expressing cells appeared in the cultures both with and without the addition of G-CSF until the tenth day. However, without G-CSF, CD16+ fractions did not appear and CD11b+ fractions were not maintained. With G-CSF, the CD16+ or CD11b+ fractions appeared only from the second week. These results suggest that G-CSF is necessary for the late stage of myeloid maturation during which CD16 and CD11b are expressed.
Antigens, CD34↗
Distinct patterns of apoptosis in association with modulation of CD44 induced by thrombopoietin and granulocyte-colony stimulating factor during ex vivo expansion of human cord blood CD34+ cells.
The insufficient number of haemopoietic stem cells (HSCs) in cord blood (CB) is the major potential limitation to widespread use of CB for marrow replacement. Cytokine-mediated ex vivo expansion has been proposed as a means of increasing the number of CB HSCs for transplantation. However, the biology of CB HSCs during cytokine-mediated ex vivo expansion, such as apoptosis or expression of adhesion molecules, has not yet been elucidated. We have investigated the patterns of apoptosis and CD44 expression on human CB CD34+ cells during ex vivo expansion. CD34+ cells isolated from human CB were cultured in a stroma-free liquid culture system with thrombopoietin (TPO), flt3-ligand (FL), stem cell factor (SCF), and/or granulocyte-colony stimulating factor (G-CSF). During the culture, for up to 5 weeks, apoptosis was measured by staining with 7-amino-actinomycin D (7-AAD) along with concurrent immunophenotyping of CD34 and CD44 with three-colour flow cytometry. In the cultures with TPO, an apoptotic fraction with down-regulated CD44 appeared from the fourth day up to the second week. G-CSF also induced apoptosis but in a different manner; the apoptotic fraction without down-regulation of CD44 appeared unremittingly for up to 5 weeks. FL did not induce apoptosis or down-regulation of CD44. These findings show that apoptosis is indeed involved in the regulation of CB CD34+ cells in ex vivo expansion and the patterns of apoptosis are dependent on the type of cytokines used. The distinct patterns of apoptosis suggest different mechanisms of TPO and G-CSF in inducing apoptosis, which still remains to be elucidated.
Antigens, CD34↗
Is obesity an underlying factor in erectile dysfunction?
OBJECTIVES: We conducted a study to evaluate the impact of obesity on erectile function in men with erectile dysfunction. METHODS: Three hundred and twenty-five consecutive patients with erectile dysfunction were evaluated. We classified the men into 2 groups according to body weight: <120% of the ideal body weight, and >/=120%. We compared several erectile capacities and the findings of penile duplex ultrasonography. RESULTS: There was a statistically significant decrease in the quality of residual erectile function in patients with obesity (penile rigidity grade 1.32 versus 1.62 in the nonobese patients). Obese patients also have an increased prevalence of vascular risk factors based on a review of the medical records and vascular impairment by duplex ultrasound study (43 and 62% in the obese patients versus 30 and 42% in the nonobese patients, respectively, p < 0.05). However, when we focused only on the patients without any vascular risk factors, no significant difference between the 2 groups was noted in the quality of residual erectile function and also the prevalence of penile vascular impairments (p > 0.05). CONCLUSIONS: These data demonstrate that obesity in itself does not seem to be an underlying factor, but does impose a risk to vasculogenic impotence by developing chronic vascular disease.
Adolescent↗
The action mechanism of relaxation effect of atropine on the isolated rabbit corpus cavernosum.
PURPOSE: Atropine has been used to block cholinergic neurotransmission in basic research and has received recent interest clinically in the intracavernosal pharmacotherapy of erectile dysfunction. It has been suggested that at a low dose (10(-8) M), atropine blocks muscarinic receptors, and that at a large dose (10(-3) M), it induces the release of EDRF. However, no report has supported this idea experimentally. We tried to confirm the action of atropine in cavernosal tissue and define its mechanism. MATERIALS AND METHODS: Strips of rabbit corpus cavernosum were mounted in organ chambers. On the precontracted muscle strips with phenylephrine (PHE; 5 x 10(-6) M), atropine was treated with increasing concentration from 10(-11) M. The relaxing activity of atropine was observed in deendothelialized tissue and preparation with treatment with methylene blue (10(-4) M), pyrogallol (10(-4) M), NW-nitro-L-arginine (L-NNA; 3 x 10(-4) M) and indomethacin (10(-4) M). To evaluate the relationship of atropine to Ca++, the muscle strip was incubated in Ca++ free solution, and Ca++ induced contraction by addition of CaCl2 (10(-3) M) was recorded with atropine. Depolarization by KCl was observed with atropine to investigate the relationship of atropine relaxation to K+. RESULTS: On the precontracted muscle strip with PHE, atropine induced a dose-related contraction up to 10(-8) M and began to exert a relaxing effect at the concentration of 10(-7) M and reached the 93.6% relaxation effect at the concentration of 10(-4) M, causing dose-dependent relaxation. The relaxing effect of atropine was partially inhibited by endothelial disruption, and by pretreatment with methylene blue, pyrogallol, L-NNA, and indomethacin, although they were not statistically significant. At the basal state of muscle strips in Ca++ free solution, atropine decreased basal tension as well as inhibited the contraction induced by CaCl2 dose-dependently. However, atropine did not influence depolarization by KCl. CONCLUSIONS: Atropine has both a contraction effect at lower concentrations and a relaxation effect at higher concentrations on cavernosal smooth muscle. It is presumed that the relaxation at higher concentrations is mediated via increasing intracellular calcium sequestration, not by hyperpolarization or secretion of EDRF.
Animals↗
Differential activation of NAD kinase by plant calmodulin isoforms. The critical role of domain I.
NAD kinase is a Ca2+/calmodulin (CaM)-dependent enzyme capable of converting cellular NAD to NADP. The enzyme purified from pea seedlings can be activated by highly conserved soybean CaM, SCaM-1, but not by the divergent soybean CaM isoform, SCaM-4 (Lee, S. H., Kim, J. C., Lee, M. S., Heo, W. D., Seo, H. Y., Yoon, H. W., Hong, J. C., Lee, S. Y., Bahk, J. D., Hwang, I., and Cho, M. J. (1995) J. Biol. Chem. 270, 21806-21812). To determine which domains were responsible for this differential activation of NAD kinase, a series of chimeric SCaMs were generated by exchanging functional domains between SCaM-4 and SCaM-1. SCaM-4111, a chimeric SCaM-1 that contains the first domain of SCaM-4, was severely impaired (only 40% of maximal) in its ability to activate NAD kinase. SCaM-1444, a chimeric SCaM-4 that contains the first domain of SCaM-1 exhibited nearly full ( approximately 70%) activation of NAD kinase. Only chimeras containing domain I of SCaM-1 produced greater than half-maximal activation of NAD kinase. To define the amino acid residue(s) in domain I that were responsible for this differential activation, seven single residue substitution mutants of SCaM-1 were generated and tested for NAD kinase activation. Among these mutants, only K30E and G40D showed greatly reduced NAD kinase activation. Also a double residue substitution mutant, K30E/G40D, containing these two mutations in combination was severely impaired in its NAD kinase-activating potential, reaching only 20% of maximal activation. Furthermore, a triple mutation, K30E/M36I/G40D, completely abolished NAD kinase activation. Thus, our data suggest that domain I of CaM plays a key role in the differential activation of NAD kinase exhibited by SCaM-1 and SCaM-4. Further, the residues Lys30 and Glu40 of SCaM-1 are critical for this function.
3',5'-Cyclic-AMP Phosphodiesterases↗
Sequential isologous organ transplantation in inbred rats: pancreaticoduodenal transplants.
A total of 847 inbred Lewis rats of mixed sex were used in this pancreaticoduodenal (Pd) donor aging study. Pd grafts were taken from 9- to 12-month-old donors and transplanted into 3-month-old recipients (thus, the first generation Pd graft, or 1 Pd). After 9 to 12 months, the same Pd grafts were again harvested and transplanted into 3-month-old rats (thus the 2 Pd generation). This cycle was repeated to obtain the 3, 4, and 5 Pd series. Sequential transplantation was able to extend the Pd grafts' mean survival time to 32 months for fourteen 4 Pd grafts, and to 39.2 months for four 5 Pd grafts (the longest lived graft survived for 42 months). The pancreas and duodenal sections of the grafts remained normal throughout the entire study. However, the aortic sections of the grafts (which were harvested to include the superior mesenteric and celiac arteries) all exhibited moderate to massive atherosclerotic changes by the 5 Pd mean survival age of 39.2 months. Such histological changes commenced even before 21 months of Pd graft age in some animals, gradually progressing to dilation of the aorta (and subsequent narrowing of aortic tributaries), as well as formation of an eggshell-like inner membrane shielding the aortic intima, by 42 months. Such atherosclerotic changes precluded transplantations beyond the 5 Pd series.
Age Factors↗
Pleomorphic adenoma of the trachea.
A case of salivary gland type pleomorphic adenoma of the trachea in a 48-year-old woman is presented. Pleomorphic adenoma is extremely rare in the trachea. The behavior of this tumor in the trachea appears to be similar to its counterpart in other sites and distinctly different from the more frequently encountered epithelial tumors.
Adenoma, Pleomorphic↗
The impact of aging on penile hemodynamics in normal responders to pharmacological injection: a Doppler sonographic study.
PURPOSE: The change in arterial flow velocity with age in patients with a normal response to pharmacological injection was evaluated. MATERIALS AND METHODS: We studied 64 patients with erectile dysfunction who responded well to intracavernous injection of 10 micrograms. prostaglandin E1 with well sustained penile rigidity for longer than 1 hour and normal cavernous arterial flow velocities on color Doppler ultrasonography. The men were classified into 4 groups according to age younger than 30 years, and 30 to 39, 40 to 49 and 50 years old or older. Flow parameters were compared. RESULTS: The statistically significant decreasing tendency of peak systolic velocity with age was revealed by a simple regression test (p = 0.003). The greatest decrease was observed between patients in the third and fourth decades. When comparing the peak systolic velocity according to timing of measurement, the greatest velocities occurred at later measurements after the fifth decade, while in younger patients these values were reached earlier. CONCLUSIONS: These data demonstrate that cavernous arterial flow during pharmacological erection decreases and the response time of the cavernous artery or tissue to a vasoactive drug becomes longer with age.
Adult↗
Explorations in a proposed national policy for children and families.
Empirical evidence suggests that the family system is under pressure in the United States. This evidence includes but is not limited to a significant increase in out-of-wedlock childbearing by teenagers, an increase in the number of children living in families below the poverty level, lack of available health care to large numbers of children and families, and a rising number of children dropping out of school. The authors offer an analysis of the problems facing families, and a national policy model for children and families is proposed.
Adolescent↗
Treating powerless minorities through an ecosystem approach.
An ecological approach to social work practice for a minority based on an ecosystem-oriented assessment-intervention model is presented. Strengths and limitations of the ecological perspective for practice are emphasized (in the context of power dynamics). A case study is presented.
Child, Preschool↗
Characterization of a cDNA encoding cysteine proteinase inhibitor from Chinese cabbage (Brassica campestris L. ssp. pekinensis) flower buds.
A cDNA encoding a new phytocystatin isotype named BCPI-1 was isolated from a cDNA library of Chinese cabbage flower buds. The BCPI-1 clone encodes 199 amino acids resulting in a protein much larger than other known phytocystatins. BCPI-1 has an unusually long C-terminus. A BCPI-1 fusion protein expressed in Escherichia coli strongly inhibits the enzymatic activity of papain, a cysteine proteinase. Genomic Southern blot analysis revealed that the BCPI gene is a member of a small multi-gene family in Chinese cabbage. Northern blot analysis showed that it is differentially expressed in the flower bud, leaf and root.
Amino Acid Sequence↗
Expressed sequence tags of Chinese cabbage flower bud cDNA.
We randomly selected and partially sequenced cDNA clones from a library of Chinese cabbage (Brassica campestris L. ssp. pekinensis) flower bud cDNAs. Out of 1216 expressed sequence tags (ESTs), 904 cDNA clones were unique or nonredundant. Five hundred eighty-eight clones (48.4%) had sequence homology to functionally defined genes at the peptide level. Only 5 clones encoded known flower-specific proteins. Among the cDNAs with no similarity to known protein sequences (628), 184 clones had significant similarity to nucleotide sequences registered in the databases. Among these 184 clones, 142 exhibited similarities at the nucleotide level only with plant ESTs. Also, sequence similarities were evident between these 142 ESTs and their matching ESTs when compared using the deduced amino acid sequences. Therefore, it is possible that the anonymous ESTs encode plant-specific ubiquitous proteins. Our extensive EST analysis of genes expressed in floral organs not only contributes to the understanding of the dynamics of genome expression patterns in floral organs but also adds data to the repertoire of all genomic genes.
Cloning, Molecular↗
Minimally differentiated acute myelogenous leukemia presented with multiple cervical lymphadenopathy.
Lymphadenopathy is a relatively uncommon finding of minimally differentiated acute myelogenous leukemia (AML-MO). We experienced a case of AML-MO in a 57-year-old man initially presented with multiple cervical lymphadenopathy. Bone marrow aspiration revealed myeloblasts, which were negative for myeloperoxidase, Sudan black B, Periodic acid-Schiff, non-specific esterase and double esterase reaction. In cell surface marker studies, CD13, CD14, CD33, CD34, CD45 and HLA-DR were present. CT scan of neck demonstrated multiple lymphadenopathy at both internal jugular chains, spinal accessory chains and submandibular area. He died about two weeks after diagnosis without specific treatment.
Fatal Outcome↗
Penile sensitivity in patients with primary premature ejaculation.
PURPOSE: We investigated penile sensory levels in patients with primary premature ejaculation to determine whether there is an etiological basis for this condition. MATERIALS AND METHODS: Penile biothesiometry was performed in 120 patients with primary premature ejaculation without erectile dysfunction and neurological deficit, and in 66 normal potent male volunteers. Vibratory thresholds were recorded at the glans penis, penile shaft, scrotum and index finger using a biothesiometer. RESULTS: On the glans penis and penile shaft the values in patients with premature ejaculation were significantly less than those in normal potent men (p < 0.001). In normal potent men an age dependency of biothesiometric parameters was noted, with a significant increase in vibratory threshold at the glans penis and penile shaft in older patients. However, in patients with premature ejaculation there were consistently decreased values without age dependency at the glans penis and penile shaft (p > 0.05). CONCLUSIONS: Patients with primary premature ejaculation have penile hypersensitivity, which provides further implications for an organic basis of premature ejaculation.
Adult↗
Transplantation of reproductive organs.
A historical review of the literature concerning replantation and transplantation of reproductive organs has included studies from this laboratory, using rats, over the past 25 years. From the basic observation of ischemic and traumatic injury due to the transplantation, syngeneic testicle transplants, resulting in a partner's impregnation and histological restoration of the testicles, led to human testicular transplantation. As to the ovarian transplants, granulosa-theca cell tumors may transform into malignancies if followed for a prolonged period as intrasplenic ovaries, and high doses (15 to 20 mg/kg b.w.) of azathioprine can produce such malignant tumors in a shorter period. By caval-portal shunt, ovarian hormones enter directly into the portal blood stream and no typical granulosa-theca cell tumors were produced, owing to the fact that the liver cannot degrade all the hormones secreted by both ovaries. While en-bloc vagino-utero-ovarian transplantation in the rat is possible, no impregnation has been yet achieved. Finally, it is hypothesized that those who have acquired microsurgical techniques and have a full understanding of the anatomy of the reproductive system will not only be able to perform replantation of the penis, but also will be capable of allogeneic transplantation of genital organs, whether ethically approved or not, and sooner than one may think. In such cases a penile part may be obtained at a sex-change surgery or from a cadaveric donor, similar to other vital organ transplantation practices.
Animals↗