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Y R Lin

Publications and source records attributed to Y R Lin.

11 recordsLinked to original sources
PubMed2004

Pleomorphic adenoma with extensive necrosis: report of two cases.

Pleomorphic adenoma (PA) is the most common neoplasm for both the major and minor salivary glands. While PA is occasionally associated with cystic change or hemorrhage necrosis, spontaneous infarction appears to be very uncommon. We report two unusual cases of extensive necrosis of PA; one occurred in the palate with the necrotic tumor mass slipping into the oral cavity. This phenomenon, possibly associated with incision biopsy, has never been described previously. A second case, arising in the parotid with spontaneous tumor necrosis, poses some dilemma in differential diagnosis.

Adenoma, Pleomorphic↗
PubMed2004

Central adenoid cystic carcinoma of the mandible manifesting as an endodontic lesion.

AIM: To present a case of adenoid cystic carcinoma (ACC) in the mandible, and manifesting as a periapical lesion. SUMMARY: A 56-year-old male suffered from pain around the right mandibular first molar for approximately 1 week. Oral examination revealed that the involved tooth was restored by a full coverage crown with no obvious abnormalities. A periapical radiograph revealed two ill-defined radiolucencies associated with the tooth, one over the mesial and another over the distal roots of the tooth; incomplete root filling and furcation involvement also being noted. The affected tooth was extracted based on the clinical impression of apical periodontitis. The surrounding tissue of the root apex was curetted and sent for histopathological examination, which revealed ACC. KEY LEARNING POINTS: Adenoid cystic carcinoma affecting the mandible may mimic a periapical lesion. Proper diagnosis of such a lesion is dependent on thorough clinical, radiographic and microscopic examinations. Such a case highlights the benefits of biopsy and histological examination of collected tissues. Diagnosis of lesions in the mandible should include salivary gland tumours.

Carcinoma, Adenoid Cystic↗
PubMed2001

Toward integration of comparative genetic, physical, diversity, and cytomolecular maps for grasses and grains, using the sorghum genome as a foundation.

The small genome of sorghum (Sorghum bicolor L. Moench.) provides an important template for study of closely related large-genome crops such as maize (Zea mays) and sugarcane (Saccharum spp.), and is a logical complement to distantly related rice (Oryza sativa) as a "grass genome model." Using a high-density RFLP map as a framework, a robust physical map of sorghum is being assembled by integrating hybridization and fingerprint data with comparative data from related taxa such as rice and using new methods to resolve genomic duplications into locus-specific groups. By taking advantage of allelic variation revealed by heterologous probes, the positions of corresponding loci on the wheat (Triticum aestivum), rice, maize, sugarcane, and Arabidopsis genomes are being interpolated on the sorghum physical map. Bacterial artificial chromosomes for the small genome of rice are shown to close several gaps in the sorghum contigs; the emerging rice physical map and assembled sequence will further accelerate progress. An important motivation for developing genomic tools is to relate molecular level variation to phenotypic diversity. "Diversity maps," which depict the levels and patterns of variation in different gene pools, shed light on relationships of allelic diversity with chromosome organization, and suggest possible locations of genomic regions that are under selection due to major gene effects (some of which may be revealed by quantitative trait locus mapping). Both physical maps and diversity maps suggest interesting features that may be integrally related to the chromosomal context of DNA-progress in cytology promises to provide a means to elucidate such relationships. We seek to provide a detailed picture of the structure, function, and evolution of the genome of sorghum and its relatives, together with molecular tools such as locus-specific sequence-tagged site DNA markers and bacterial artificial chromosome contigs that will have enduring value for many aspects of genome analysis.

DNA Fingerprinting↗
PubMed2000

Locus-specific contig assembly in highly-duplicated genomes, using the BAC-RF method.

Polyploidy, the presence of multiple sets of chromosomes that are similar but not identical, complicates both chromosome walking and assembly of sequence-ready contigs for many plant taxa including a large number of economically-significant crops. Traditional 'dot-blot hybridization' or PCR-based assays for identifying BAC clones corresponding to a mapped DNA landmark usually do not provide sufficient information to distinguish between allelic and non-allelic loci. A restriction fragment matching method using pools of BAC DNA in combination with dot-blots reveals the locus specificity of individual BACs that correspond to multi-locus DNA probes, in a manner that can efficiently be applied on a large scale. This approach also provides an alternative means of mapping DNA loci that exploits many advantages of 'radiation hybrid' mapping in taxa for which such hybrids are not available. The BAC-RF method is a practical and reliable approach for using high-density RFLP maps to anchor sequence-ready BAC contigs in highly-duplicated genomes, provides an alternative to high-density robotic gridding for screening BAC libraries when the necessary equipment is not available, and permits the expedient isolation of individual members of multigene or repetitive DNA families for a wide range of genetic and evolutionary investigations.

Chromosomes, Bacterial↗
PubMed1998

Detailed alignment of saccharum and sorghum chromosomes: comparative organization of closely related diploid and polyploid genomes.

The complex polyploid genomes of three Saccharum species have been aligned with the compact diploid genome of Sorghum (2n = 2x = 20). A set of 428 DNA probes from different Poaceae (grasses) detected 2460 loci in F1 progeny of the crosses Saccharum officinarum Green German x S. spontaneum IND 81-146, and S. spontaneum PIN 84-1 x S. officinarum Muntok Java. Thirty-one DNA probes detected 226 loci in S. officinarum LA Purple x S. robustum Molokai 5829. Genetic maps of the six Saccharum genotypes, including up to 72 linkage groups, were assembled into "homologous groups" based on parallel arrangements of duplicated loci. About 84% of the loci mapped by 242 common probes were homologous between Saccharum and Sorghum. Only one interchromosomal and two intrachromosomal rearrangements differentiated both S. officinarum and S. spontaneum from Sorghum, but 11 additional cases of chromosome structural polymorphism were found within Saccharum. Diploidization was advanced in S. robustum, incipient in S. officinarum, and absent in S. spontaneum, consistent with biogeographic data suggesting that S. robustum is the ancestor of S. officinarum, but raising new questions about the antiquity of S. spontaneum. The densely mapped Sorghum genome will be a valuable tool in ongoing molecular analysis of the complex Saccharum genome.

DNA, Plant↗
PubMed1995

The weediness of wild plants: molecular analysis of genes influencing dispersal and persistence of johnsongrass, Sorghum halepense (L.) Pers.

Many major weeds rely upon vegetative dispersal by rhizomes and seed dispersal by "shattering" of the mature inflorescence. We report molecular analysis of these traits in a cross between cultivated and wild species of Sorghum that are the probable progenitors of the major weed "johnsongrass." By restriction fragment length polymorphism mapping, variation in the number of rhizomes producing above-ground shoots was associated with three quantitative trait loci (QTLs). Variation in regrowth (ratooning) after overwintering was associated with QTLs accounting for additional rhizomatous growth and with QTLs influencing tillering. Vegetative buds that become rhizomes are similar to those that become tillers--one QTL appears to influence the number of such vegetative buds available, and additional independent genes determine whether individual buds differentiate into tillers or rhizomes. DNA markers described herein facilitate cloning of genes associated with weediness, comparative study of rhizomatousness in other Poaceae, and assessment of gene flow between cultivated and weedy sorghums--a risk that constrains improvement of sorghum through biotechnology. Cloning of "weediness" genes may create opportunities for plant growth regulation, in suppressing propagation of weeds and enhancing productivity of major forage, turf, and "ratoon" crops.

Journal Article↗
PubMed1995

Comparative analysis of QTLs affecting plant height and maturity across the Poaceae, in reference to an interspecific sorghum population.

Correspondence among QTLs affecting height and/or flowering was investigated across the five races of sorghum, an interspecific sorghum F2 population, and 32 previously published sorghum, maize, rice, wheat, and barley populations revealing 185 QTLs or discrete mutants. Among nine QTLs mapped in the interspecific sorghum population (six affecting height and three affecting flowering), at least seven (78%) are associated with "conversion," backcross-introgression of alleles imparting reduced height or earlier flowering from cultivated sorghums into one or more exotic Sorghum bicolor races. One chromosomal region was "converted" in all S. bicolar races--in the interspecific F2, this region explained 54.8% of height variation (putatively the Dw2 gene) and 85.7% of flowering time variation (putatively Ma1). Comparative data suggest that Ma1 and Dw2 orthologs influence height and flowering of other Poaceae taxa and support classical dogma that the sorghum phenotypes attributed to Ma1 and Dw2 (respectively) are due to different genetic loci. Other sorghum QTLs also showed correspondence with those in other Poaceae, more frequently than would be expected by chance. Possible homoeologous QTLs were found within both the maize and sorghum genomes. Comparative QTL mapping provides a means to unify, and thereby simplify, molecular analysis of complex phenotypes.

Chromosome Mapping↗