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PubMed2006

Degeneration of the pulmonary autograft: an explant study.

OBJECTIVE: We sought to determine the histologic features of pulmonary autografts explanted after the Ross operation. METHODS: Histologic sections of 30 explanted autografts and 8 normal heart valves were compared and semiquantitatively scored by a blinded cardiovascular pathologist. RESULTS: Pulmonary autografts (n = 30) were explanted on average 6.1 +/- 0.6 years (median, 6.6 years; range, 0.1-11.7 years) after the Ross operation (n = 28) or removed at autopsy (n = 2). Twelve (43%) of the patients undergoing reoperation had no or negligible autograft insufficiency on early transthoracic echocardiography, 12 (43%) had grade 1 autograft insufficiency, and 4 (14%) had grade 1-2 autograft insufficiency. Valve regurgitation with root dilatation was the most common indication for reoperation after root replacement (n = 26 [93%]) and regurgitation after subcoronary implanted autografts (n = 2 [7%]). Microscopy of the autograft explants revealed normal laminar architecture and cellularity. Wall specimens were characterized by reduced and fragmented elastin and increased collagen levels (fibrosis). Medial elastin changes were associated with the presence of hypertrophic smooth muscle cells. Fibrosis was most severe in the adventitia. Intimal thickening was a common finding. Valve explants showed significant thickening caused by fibrocellular tissue on the ventricular surface and marked thickening of the free margin. An autopsy explant with normal function before death showed similar features. CONCLUSIONS: Pulmonary autograft explants showed severe aneurysmal degeneration of the wall, which was characterized by intimal thickening, medial elastin fragmentation, and adventitial fibrosis. Valve leaflets were thickened. The presence of these features in a nonfailing explant suggests these changes represent a common mode of remodeling.

Adolescent↗
PubMed2002

Chymase inhibition suppresses high-cholesterol diet-induced lipid accumulation in the hamster aorta.

OBJECTIVE: The role of chymase (a mast cell-derived angiotensin II-forming serine proteinase) in aortic lipid deposition was investigated using an orally active, non-peptide chymase inhibitor, SUN-C8257. METHODS: Male golden Syrian hamsters, 8 weeks old, were fed with a standard rodent meal supplemented with or without 0.5% cholesterol and 10% coconut oil for 12 weeks. The hamsters fed high cholesterol diet were further separated into two groups treated with or without SUN-C8257 for 12 weeks. The aortic lipid deposition was visualized by Oil red O staining and planimetrically measured. Immunohistochemical staining for angiotensin II (Ang II) of the aortic root region was performed. Aortic Ang II-forming activity was measured using Ang I as a substrate. Plasma total-, low-density lipoprotein (LDL)-, high-density lipoprotein (HDL)-cholesterol and triglyceride were quantified by enzymatic methods. Plasma Ang I and Ang II were measured by radioimmunoassay. RESULTS: After 12 weeks of high cholesterol diet, aortic chymase activity in the untreated group increased significantly and showed a positive correlation with plasma total- and LDL-cholesterol. This group of hamsters developed marked lipid deposits in the aortic intima. However, treatment with SUN-C8257 significantly suppressed aortic lipid deposition without changing body weight, blood pressure, plasma LDL-cholesterol and Ang II levels. The level of the adventitial Ang II-immunoreactivity was markedly inhibited in the group treated with SUN-C8257. CONCLUSION: Our results suggest that arterial chymase may participate in the acceleration of lipid deposition in arterial walls exposed to high plasma cholesterol and that inhibition of arterial chymase may retard the progression of atherosclerosis.

Analysis of Variance↗
PubMed1999

[Preliminary studies on tissue culture and agrobacterium-medicated transformation of Brassica campestris ssp. chinensis].

The hypocotyls and cotyledons of the asepetic seedling of Brassica campestris ssp. chinensis L cv. Pudongaijiecai) were used as explants for tissue culture. Adventitious buds were differentiated on modified MS medium supplemented with TDZ 1-2 mg/L, NAA 0.2-1 mg/L and AgNO3 7.5 mg/L. The percentage of explants which formed buds of cotyledons was about 56%, and that of hypocotyls was about 37%. When the regenerated explants were transferred onto MS medium with 2 i.p. 5 mg/L and NAA 0.1 mg/L for two weeks, whole plantlets were obtained by culturing the regenerated shoots on 1/2 MS medium with NAA 0.1 mg/L. Agrobacterium tumefaciens strain (LBA 4404/PBI 121) carrying the GUS gene and Npt II gene was used for transformation. After 2 days of coculture, the hypocotyls and cotyledons were transferred onto regenerated medium containing CP 300 mg/L for bud formation. After 4-5 weeks, the differentiated buds were transferred onto selection medium with CP 200 mg/L and Km 10 mg/L for 1 month, then the green shoots were transferred onto the rooting medium containing Cef 100 mg/L and Km 20 mg/L. 4-5 weeks later, plantlets with Km resistance were obtained and some of them showed higher enzymatic activities of beta-glucuronidase than control ones.

Brassica↗
PubMed2003

Adventitious shoot regeneration from in vitro cultured leaves of London plane tree (Platanus acerifolia Willd.).

Adventitious shoots were successfully regenerated from leaf explants of in vitro cultures of Platanus acerifolia Willd. The leaves of three clones (genotypes), designated as PH1, PH2 and PC, respectively, were wounded by three to four transverse cuts through the midvein and cultured on 26 media based on Murashige and Skoog (MS) basal medium, containing different concentrations of 6-benzylaminopurine (BAP) in combination with different concentrations of indole-3-butyric acid (IBA). The highest regeneration rate (>90%) and the largest number of shoot clumps per regenerating leaf (>4 shoot clumps/explant) were obtained with leaves of genotype PH2 cultured on MS basal medium supplemented with 17.76 microM BAP and 4.92 microM IBA. The other two genotypes, PH1 and PC, showed very low capability of shoot regeneration (<10%) on all the media tested. Shoots on leaf explants originated mainly from callus that developed around the cut end of petioles and along the cuts across the midvein. The regenerated shoots were micropropagated, rooted and transplanted to the soil successfully.

Adenine↗
PubMed2002

Molecular analysis of signals controlling dormancy and growth in underground adventitious buds of leafy spurge.

Dormancy and subsequent regrowth of adventitious buds is a critical physiological process for many perennial plants. We have used the expression of hormone and cell cycle-responsive genes as markers to follow this process in leafy spurge (Euphorbia esula). In conjunction with earlier studies, we show that loss of mature leaves results in decreased sugar levels and increased gibberellin perception in underground adventitious buds. Gibberellin is sufficient for induction of S phase-specific but not M phase-specific gene expression. Loss of both apical and axillary buds or inhibition of polar auxin transport did not result in induction of S phase- or M phase-specific gene expression. Loss of polar auxin transport was necessary for continuation of the cell cycle and further bud development if the S phase was previously initiated.

Arabidopsis Proteins↗
PubMed2000

An efficient method for the production of transgenic plants of peanut (Arachis hypogaea L.) through Agrobacterium tumefaciens-mediated genetic transformation.

Cotyledon explants from mature peanut seeds (Arachis hypogaea L.) were optimized to obtain adventitious shoot buds with high frequencies (>90%). Efficient transformation of these cotyledons by using Agrobacterium tumefaciens strain C58 carrying neomycin phosphotransferase II (nptII) and ß-glucuronidase (GUS; uidA), or coat protein gene of the Indian peanut clump virus (IPCVcp) and nptII on binary vectors (pBI121; pROKII:IPCVcp) led to the production of a large percentage (55%) of transgenic plants. Transformed individuals were obtained through selection on medium containing 125 mg l(-1) kanamycin. A large number of independently transformed plants (over 75) were successfully transplanted to the glasshouse. Integration of the transgenes and stable genetic transformants in the progeny were assessed by PCR amplification of 700-bp fragment of nptII and 585-bp of IPCVcp genes, and Southern blot hybridizations in the T1 generation of transgenic plants. Analysis of 35 transgenic plants of T1 generation from the progeny of a single transformation event suggested the segregation of a single copy insert in a 3:1 Mendelian ratio. On an average, 120-150 days were required between the initiation of explant transformation and transfer of rooted plants to the greenhouse. The cotyledon regeneration system proved to be an excellent vehicle for the production of a large number of independently transformed peanut plants. Shoot formation was rapid and prolific, and a large proportion of these shoots developed into fertile plants. The method reported here provides new opportunities for the crop improvement of peanut via genetic transformation.

Journal Article↗
PubMed1993

Possible origins and distribution of immunoreactive nitric oxide synthase-containing nerve fibers in cerebral arteries.

The distribution of perivascular nerve fibers expressing nitric oxide synthase (NOS)-immunoreactivity was examined in Sprague-Dawley and Long-Evans rats using affinity-purified rabbit antisera raised against NOS from rat cerebellum. NOS immunoreactivity was expressed within the endothelium and adventitial nerve fibers in both rat strains. Labeled axons were abundant and dense in the proximal anterior and middle cerebral arteries, but were less numerous in the caudal circle of Willis and in small pial arteries. The sphenopalatine ganglia were the major source of positive fibers in these vessels. Sectioning postganglionic parasympathetic fibers from both sphenopalatine ganglia reduced the density of NOS-immunoreactive (IR) nerve fibers by > 75% in the rostral circle of Willis. Moreover, NOS-IR was present in 70-80% of sphenopalatine ganglion cells. Twenty percent of these neurons also contained vasoactive intestinal polypeptide (VIP)-immunoreactivity. By contrast, the superior cervical ganglia did not contain NOS-IR cells. In the trigeminal ganglion, NO-IR neurons were found chiefly within the ophthalmic division; approximately 10-15% of neurons were positively labeled. Colocalization with calcitonin gene-related peptide (CGRP) was not observed. Sectioning the major trigeminal branch innervating the circle of Willis decreased positive fibers by < or = 25% in the ipsilateral vessels. In the nodose ganglion, 20-30% of neurons contained NOS-immunoreactivity, whereas less than 1% were in the C2 and C3 dorsal root ganglia. Three human circles of Willis obtained at autopsy showed sparse immunoreactive fibers, chiefly within vessels of the posterior circulation. Postmortem delay accounted for some of the reduced density. Our findings indicate that nerve fibers innervating cerebral arteries may serve as a nonendothelial source of the vasodilator nitric oxide (NO). The coexistence of NOS and VIP within sphenopalatine ganglion cells raises the possibility that two vasodilatory agents, one, a highly diffusable short-lived, low-molecular-weight molecule, and the other, a polar 28 amino acid-containing peptide, may serve as coneuromediators within the cerebral circulation.

Amino Acid Oxidoreductases↗
PubMed1993

Adventitious variability? The amino acid sequences of nonvertebrate globins.

1. The more than 140 amino acid sequences of non-vertebrate hemoglobins (Hbs) and myoglobins (Mbs) that are known at present, can be divided into several distinct groups: (1) single-chain globins, containing one heme-binding domain; (2) truncated, single-chain, one-domain globins; (3) chimeric, one-domain globins; (4) chimeric, two-domain globins; and (5) chimeric multi-domain globins. 2. The crystal structures of eight nonvertebrate Hbs and Mbs are known, all of them monomeric, one-domain globin chains. Although these molecules represent plants, prokaryotes and several metazoan groups, and although the inter-subunit interactions in the dimeric and tetrameric molecules differ from the ones observed in vertebrate Hbs, the secondary structures of all seven one-domain globins retain the characteristic vertebrate "myoglobin fold". No crystal structures of globins representing the other four groups have been determined. 3. Furthermore, a number of the one-, two- and multi-domain globin chains participate in a broad variety of quaternary structures, ranging from homo- and heterodimers to highly complex, multisubunit aggregates with M(r) > 3000 kDa (S. N. Vinogradov, Comp. Biochem. Physiol. 82B, 1-15, 1985). 4. (1) The single-chain, single-domain globins are comparable in size to the vertebrate globins and exhibit the widest distribution. (A) Intracellular Hbs include: (i) the monomeric and polymeric Hbs of the polychaete Glycera; (ii) the tetrameric Hb of the echiuran Urechis; (iii) the dimeric Hbs of echinoderms such as Paracaudina and Caudina; and (iv) the dimeric and tetrameric Hbs of molluscs, the bivalves Scapharca, Anadara, Barbatia and Calyptogena. (B) Extracellular Hbs include: (i) the multiple monomeric and dimeric Hbs of the larva of the insect Chironomus; (ii) the Hbs of nematodes such as Trichostrongylus and Caenorhabditis; (iii) the globin chains forming tetramers and dodecamers and comprising approximately 2/3 of the giant (approximately 3600 kDa), hexagonal bilayer (HBL) Hbs of annelids, e.g. the oligochaete Lumbricus and the polychaete Tylorrhynchus and of the vestimentiferan Lamellibrachia; and (iv) the globin chains comprising the ca 400 kDa Hbs of Lamellibrachia and the pogonophoran Oligobrachia. (C) Cytoplasmic Hbs include: (i) the Mbs of molluscs, the gastropods Aplysia, Bursatella, Cerithedea, Nassa and Dolabella and the chiton Liolophura; (ii) the three Hb of the symbiont-harboring bivalve Lucina; (iii) the dimeric Hb of the bacterium Vitreoscilla; and (iv) plant Hbs, including the Hbs of symbiont-containing legumes (Lgbs), the Hbs of symbiont-containing non-leguminous plants and the Hbs in the roots of symbiont-free plants.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗