QTL analysis for rice grain length and fine mapping of an identified QTL with stable and major effects

Grain length in rice plays an important role in determining rice appearance, milling, cooking and eating quality. In this study, the genetic basis of grain length was dissected into six main-effect quantitative trait loci (QTLs) and twelve pairs of epistatic QTLs. The stability of these QTLs was evaluated in four environments using an F7 recombinant inbred line (RIL) population derived from the cross between a Japonica variety, Asominori, and an Indica variety, IR24. Moreover, chromosome segment substitution lines (CSSLs) harboring each of the six main-effect QTLs were used to evaluate gene action of QTLs across eight environments. A major QTL denoted as qGL-3a, was found to express stably not only in the isogenic background of Asominori but also in the recombinant background of Asominori and IR24 under multiple environments. The IR24 allele at qGL-3a has a positive effect on grain length. Based on the test of advanced backcross progenies, qGL-3a was dissected as a single Mendelian factor, i.e., long rice grain was controlled by a recessive gene gl-3. High-resolution genetic and physical maps were further constructed for fine mapping gl-3 by using 11 simple sequence repeat (SSR) markers designed using sequence information from seven BAC/PAC clones and a BC4F2 population consisting of 2,068 individuals. Consequently, the gl-3 gene was narrowed down to a candidate genomic region of 87.5 kb long defined by SSR markers RMw357 and RMw353 on chromosome 3, which provides a basis for map-based cloning of this gene and for marker-aided QTL pyramiding in rice quality breeding.

QTL detection for eating quality of cooked rice in a population of chromosome segment substitution lines

The genetic mechanism underlying six palatability properties of cooked rice and three physico-chemical traits was dissected in 66 BC(3)F(2) chromosome segment substitution lines (CSSLs), using a complete linkage map in three successive years. The CSSLs showed transgressive segregation for all traits studied. Significant correlation was detected among most palatability traits. A total of 25 QTLs for the nine traits were identified on nine chromosomes, and many QTLs affecting different quality traits were mapped in the same regions. Six QTLs--qLT-8 for luster, qTD-6 and qTD-8 for tenderness, qIVOE-6 and qIVOE-8 for integrated value of organoleptic evaluation, and qAC-8 for amylose content--were repeatedly detected across the 3 years. Phenotypic values were significantly different between the recurrent parent, cultivar Asominori, and the CSSLs harboring any of the six QTL alleles across the three environments, indicating that these six QTLs were non-environment-specific and could be used for marker-assisted selection in rice quality improvement.

Management of incision design in symphysis graft procedures: a review of the literature

Symphysis graft procedures are being performed in clinical practice more frequently than ever before. Convenient surgical access, proximity of donor and recipient sites, low morbidity, availability of larger quantities of bone over other donor sites, minimal resorption, no hospitalization, and minimal discomfort are some advantages of this procedure over other intraoral sites. Three types of horizontal incisions can be performed during this procedure: the sulcular, the marginal, and the alveolar mucosal. Most studies regarding the chin graft technique are more concerned with the bone graft aspect than soft tissue management. Moreover, the criteria for the selected flap design appear to be based primarily on clinical experience or the same surgical approach regardless of interfacing factors. The periodontal status, amount of bone loss, periodontal risk of root fenestration, amount of keratinized gingiva, restorations in the gingival margin, and local musculature are some of the clinical findings that should be assessed to indicate the best incision design. In this review article, the advantages, disadvantages, indications, and contraindications of each incision design will be discussed.

Effect of locally delivered minocycline microspheres on markers of bone resorption

BACKGROUND

Gingival crevicular fluid (GCF) biomarkers associated with bone resorption may be useful to determine periodontal disease status and response to therapy. The pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), a bone-specific degradation product, and interleukin 1-beta (IL-1), a potent bone-resorptive cytokine, have both been associated with periodontal disease activity. Minocycline is a tetracycline derivative possessing antimicrobial effects on periodontal pathogens and inhibitory properties on matrix metalloproteinases (MMPs) associated with tissue destruction. The aim of this study was to evaluate the effect of periodontal treatment in the form of scaling and root planing (SRP) and locally administered minocycline microspheres on the GCF levels of ICTP and IL-1.

METHODS

Forty-eight chronic periodontitis patients were randomly assigned to 2 groups (SRP plus subgingival application of vehicle control [SRP + V], or SRP plus subgingival application of minocycline microspheres [SRP + M]) and monitored at 8 sites per subject at baseline and 1, 3, and 6 months. Four shallow (PD < or = 3 mm) and 4 deep (PD > or = 5 mm) sites were evaluated for both marker levels and for probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP). Eight periodontally healthy control subjects with no probing depths >3 mm and no loss of attachment were also monitored at the same time intervals. GCF levels of ICTP and IL-1 were determined using radioimmunoassay and enzyme-linked immunosorbent assay techniques, respectively.

RESULTS

Significant differences (P<0.001) in GCF levels of ICTP and IL-1 were found between deep and shallow sites at all time points in both treatment groups. In addition, healthy subjects demonstrated significantly reduced levels of both markers compared to both shallow and deep sites in periodontitis patients (P <0.001). Only the SRP + M treated patients exhibited significant reductions (P <0.05) in both ICTP and IL-1 levels 1 month after treatment. Furthermore, the SRP + M group demonstrated significantly lower IL-1 levels (P <0.02) at 1 month compared to the SRP + V group.

CONCLUSIONS

Results of this study indicate that GCF levels of ICTP and IL-1 correlate with clinical measures of periodontal disease and may aid in assessing disease status and response to periodontal therapy. Furthermore, local administration of minocycline microspheres led to a potent short-term reduction in GCF IL-1 levels. Additional studies are needed to address whether repeated administration of scaling and root planing along with minocycline microspheres will achieve long-term reductions in GCF ICTP and IL-1 levels.

Assessment of newly developed tongue sulfide probe for detecting oral malodor

AIM

The present study examined the relationship between sulfide levels on tongue dorsum surfaces (pS levels) and oral malodor.

METHOD

The pS levels of 20 systemically healthy volunteers were evaluated using an industrial device equipped with a newly-developed tongue sulfide probe. The pS levels on 3 parts of the tongue--anterior, middle and posterior along the median groove of the tongue dorsum--were determined for each subject.

RESULTS

The device reported the pS level in a digital score ranging from 0.0 (< 10(-7) M of sulfide) to 5.0 (> or = 10(-2) M of sulfide) in increments of 0.5. Oral malodor was assessed by measuring the level of volatile sulfur compounds in mouth air, as well as by the organoleptic method. The pS levels were 0.03 +/- 0.11, 0.20 +/- 0.41 and 0.88 +/- 0.76 for the anterior, middle and posterior parts, respectively. This difference was significant (p<0.001). Both oral malodor measurements showed significant correlation (p<0.05) with the pS levels of middle and posterior parts of tongue.

CONCLUSION

It was concluded that the tongue sulfide probe might be useful in management of subjects with oral malodor.

[Expression, purification and identification of human matrix metalloproteinase-2]

The expression sequence of matrix metalloproteinase-2 (MMP-2) has been obtained by PCR amplifying, restriction enzyme cut and sequencing analysis demonstrate that the sequence is correct. The recombinant expression plasmid pPIC9/MMP-2 containing MMP-2 is constructed and transformed the yeast Pichia pastoris. Recombinant matrix metalloproteinase-2 protein was expressed in Pichia pastoris in great deal after induction by methanol. The purity of the recombinant MMP-2 filtrated through Sephacryl S-200 reached to electrophoresis purity. With the ability to degrade gelatin and IV type collagen, recombinant MMP-2 has the similar substrate specificity with natural MMP-2. The recombinant MMP-2 with 50 kD molecular weight is smaller than natural MMP-2, which suggested degradation occurred to it.

Immunohistochemical distinction between primary adenocarcinoma of the bladder and secondary colorectal adenocarcinoma

Primary adenocarcinoma of the urinary bladder sometimes causes a diagnostic dilemma because it can be indistinguishable morphologically from adenocarcinoma of colorectal origin secondarily involving the bladder by metastasis or direct extension. It is much less well studied than conventional urothelial carcinoma and colorectal adenocarcinoma because of its rarity. The current study was specifically designed to investigate whether an important mechanism involved in the pathogenesis of colorectal adenocarcinoma, beta-catenin dysregulation, was also important for the development of primary bladder adenocarcinoma and whether these two morphologically similar tumors could be distinguished immunohistochemically. Formalin-fixed, paraffin-embedded tissues from 17 primary adenocarcinomas of the urinary bladder, 16 colorectal adenocarcinomas involving the bladder, and 10 conventional urothelial (transitional) carcinomas were included in this study. Thirteen of the primary bladder adenocarcinomas were moderately to well differentiated (enteric type) and morphologically indistinguishable from colorectal cancers. The remaining four primary tumors were poorly differentiated (two cases) or of clear cell type (two cases). Immunohistochemical studies using a panel of monoclonal antibodies demonstrated positive nuclear staining for beta-catenin expression in 13 of the 16 (81%) colorectal adenocarcinomas secondarily involving the bladder but in none of the primary adenocarcinomas or the urothelial carcinomas. Instead, positive membranous (and some cytoplasmic) staining was present in all primary bladder tumors with the exception of two poorly differentiated adenocarcinomas where no beta-catenin staining was detected. All secondary colorectal adenocarcinomas stained negatively for CK7 and thrombomodulin (TM), whereas positivity for CK20 was observed in 15 (94%) cases. All urothelial carcinomas stained positively for CK7 and TM, and four of them also for CK20. Primary adenocarcinomas of the bladder showed mixed staining patterns for CK7, CK20, and TM with a positive rate of 65%, 53%, and 59%, respectively. These data indicate that dysregulation of beta-catenin, an important aberration seen in colorectal carcinogenesis, does not appear to play a role in the pathogenesis of the bladder adenocarcinoma. In addition, our data demonstrate that a panel of immunostains, including CK7, CK20, TM, and beta-catenin, is of diagnostic value in differentiating primary bladder adenocarcinoma from secondary adenocarcinoma of colorectal origin.

Attachment, proliferation and differentiation of periodontal ligament cells on various guided tissue regeneration membranes

The purpose of this study was to evaluate the biological effects of guided tissue regeneration (GTR) membrane materials, per se, on the periodontal tissue regeneration. Rat periodontal ligament (PDL)-derived cells were used to study the attachment, proliferation and differentiation, in vitro, on various GTR membranes. Five commercially available membranes bovine type I collagen (BioMend; BM), bovine type I atelocollagen (Tissue Guide; TG), polylactic acid (Epi-Guide; EG), co-polymer of polylactic acid and polyglycolic acid (Resolute; RL) and expanded polytetrafluoroethylene: e-PTFE (Gore Tex; GT)-were examined. A 3 x 3 mm section of the membrane was fixed to the bottom of a 35 x 10 mm style culture dish and plated with 2 ml of cell suspension at an initial density of 5 x 10(4) cells/ml in culture medium with 10% fetal bovine serum. For cell growth analysis, the specimens were fixed with 10% buffered formalin and stained with hematoxylin at 1.5 hours and 1, 3 and 5 days after cell seeding. The number of cells included in a unit area of 0.25 mm2 were counted under light microscopy. As a comparative scaffold of cell proliferation, a plastic cover for cell culture slip (Celldesk; CD) was used. For analysis of cell differentiation, activity of alkaline phosphatase (ALP) and calcification were histochemically revealed after 2-week cultivation. The initial number of PDL cells attached to the membrane at 1.5 hours after cell seeding was different among membranes. RL, TG and EG had the same level of attached cell numbers as that on CD, while the cell numbers on GT and BM were significantly lower than that on CD (p < 0.01). The rate of cell proliferation with time also differed among the membranes examined. RL and BM demonstrated a significantly higher number of cells at 5 days than at 1.5 hours (p < 0.01). TG had increased numbers of cells at 3 and 5 days after cell seeding. However, there was no statistical difference between the cell numbers at 1.5 hours and 5 days after cell seeding (p > 0.1). EG had a similar number of cell attachments to that at 1.5 hours throughout the experimental period. There was almost no cell proliferation on GT. Cell clusters of ALP positive cells and foci of calcification were seen on all membranes except for GT, where a scant number of cells were seen. Results from this study implied that GTR membrane materials, per se, may influence cell proliferation and differentiation in the process of periodontal tissue regeneration.

cDNA arrays and immunohistochemistry identification of CD10/CALLA expression in hepatocellular carcinoma

The histological diagnosis of hepatocellular carcinoma (HCC) can be complicated by difficulty in differentiation from cholangiocarcinoma and metastatic carcinoma. Immunohistochemical stains currently in use are suboptimal in terms of specificity and sensitivity. Using cDNA array analysis for differential gene expression, we demonstrated a significant increase in mRNA expression level of CD10/CALLA, a type 2 cell-surface metalloproteinase, in HCC, which was subsequently confirmed by reverse transcriptase-polymerase chain reaction and Western blotting analysis. To test the possibility of using CD10/CALLA as a diagnostic marker for HCC, various intrahepatic tumors were studied immunohistochemically using a monoclonal antibody for CD10. A characteristic canalicular-staining pattern was observed in normal hepatocytes and at the apical surface of bile duct epithelial cells. The canalicular expression of CD10 was identified in 9 of 15 HCCs examined (60%), whereas 10 cholangiocarcinomas and 8 of 9 metastatic carcinomas lacked this staining. In three of the six HCCs negative for CD10, the surrounding nonneoplastic liver tissue was also negative, suggesting fixation-associated loss of immunoreactivity. Six HCCs had stronger CD10 staining in tumor cells when compared to the surrounding nonneoplastic tissue. Three cases of benign bile duct adenomas also expressed CD10 at the luminal aspect. One of the MCs showed a diffuse, cytoplasmic staining for CD10, a pattern readily distinguishable from that of HCC. A panel of other immunohistochemical markers were also studied for comparison, including polyclonal anti-carcinoembryonic antigen, cytokeratin (CK) 7, CK20, and alpha-fetoprotein. Our results demonstrate that cDNA arrays can be effectively used to identify new diagnostic markers, and that CD10 is a reliable marker for identifying HCC, particularly when used in conjunction with a panel of immunohistochemical markers (polyclonal anti-carcinoembryonic antigen, CK7, CK20, and alpha-fetoprotein) and in the distinction from cholangiocarcinoma.

Comparison of 2 clinical techniques for treatment of gingival recession

BACKGROUND

In early case studies, use of a collagen barrier as a guided tissue regeneration (GTR) material has shown particular promise in procedures aimed at root coverage. The similarities between collagen membrane and subepithelial connective tissue graft (SCTG) have made collagen membrane an attractive and a possible alternative material for root coverage. The purpose of this randomized clinical trial was to compare these 2 techniques, SCTG versus a GTR-based procedure (GTRC), for root coverage/recession treatment.

METHODS

Sixteen patients with bilateral Miller's Class I or II (gingival recession > or = 3.0 mm) recession defects were treated either with SCTG or GTRC using a newly designed collagen membrane. Clinical parameters monitored included recession depth (RD), clinical attachment level (CAL), probing depth (PD), width of keratinized gingiva (KG), attached gingiva (AG), and recession width (RW), each measured at the mid-buccal area to the nearest 0.5 mm. Measurements were taken at baseline and 6 months. A standard mucogingival surgical procedure was performed. Data were reported as means +/- SD and were analyzed using the paired t test for univariate analysis and restricted/residual maximal likelihood (REML)-based mixed effect model for multivariate analysis.

RESULTS

No statistically significant differences were observed in RD, CAL, KG, and AG between test and control groups at either time period. However, SCTG showed significantly more residual PD and more RW gain when compared to GTRC at 6 months. Both treatments resulted in a statistically significant (P < 0.05) reduction of recession defects (2.5 mm and 2.8 mm), gain of CAL (2.8 mm and 2.3 mm), reduction of RW (1.9 mm and 2.7 mm), and increase of KG (0.7 mm and 1.1 mm) and AG (0.7 mm and 0.5 mm) for GTRC and SCTG, respectively, when comparing 6-month data to baseline. Mean root coverage of 73% (collagen membrane) and 84% (subepithelial connective tissue graft) was achieved.

CONCLUSIONS

The 2 techniques are clinically comparable. Use of a modified collagen membrane to attain root coverage may alleviate the need for donor site procurement of connective tissue.

The use of autologous fibrinogen concentrate in treating ocular hypotony after glaucoma filtration surgery

Antimetabolite therapy with 5-fluouracil (5-FU) or mitomycin-C (MMC) has significantly improved the success rate of glaucoma filtration surgery. However, in some eyes, when filtration is excessive, persistent hypotony may develop. In this study, we describe the experience of using autologous fibrinogen concentrate (AFC) to treat patients with persistent hypotony after glaucoma filtration surgery. Among seven MMC-augmented trabeculectomy patients who developed persistent postoperative hypotony, the effects of AFC intrableb injections were evaluated. Under a microscope, 0.2 ml AFC and bovine thrombin were injected into the blebs of the patients from both sides of the filtering blebs. Postoperative best-corrected visual acuity, anterior chamber status, intraocular pressure (IOP) and fundus examination were followed and compared with those preoperative. On the second day, the mean IOP of seven eyes elevated from preoperative 3.4 +/- 2.1 mmHg to 12.6 +/- 4.2 mmHg, and the anterior chamber became deep without obvious inflammatory response. Within two weeks, macular edema and visual acuity were noted to improve in six eyes (85.7%). In addition, after a mean follow-up of 25 months, the trabeculectomy procedure remained successful in all eyes. AFC appears to be safe and effective in the treatment of ocular hypotony after glaucoma filtration surgery.

Association between oral malodor and adult periodontitis: a review

BACKGROUND

Bad breath has a significant impact on our daily social life to those who suffer from it. The majority of bad breath originates within the oral cavity. However, it is also possible that it can come from other sources such as gastric-intestine imbalance. The term "oral malodor" is used to describe a foul or offensive odor emanating from the oral cavity, in which proteolysis, metabolic products of the desquamating cell, and bacterial putrefaction are involved. Recent evidence has demonstrated a link between oral malodor and adult periodontitis. The process of developing bad breath is similar to that noted in the progression of gingivitis/periodontitis. Oral malodor is mainly attributed to volatile sulfur compounds (VSC) such as hydrogen sulfide, methyl mercaptan and dimethyl sulfide. The primary causative microbes are gram-negative, anaerobic bacteria that are similar to the bacteria causing periodontitis. These bacteria produce the VSC by metabolizing different cells/tissues (i.e., epithelial cells, leukocytes, etc.) located in saliva, dental plaque, and gingival crevicular fluid. Tongue surface is composed of blood components, nutrients, large amounts of desquamated epithelial cells and bacteria, suggesting that it has the proteolytic and putrefactive capacity to produce VSC. One of the challenges in dealing with oral malodor is to identify a reliable test for detecting bad breath.

AIMS

The purposes of this review article were: (1) to correlate the relationship between oral malodor and adult periodontitis; (2) to analyze current malodor tests and discuss available treatment regimens.

A scytalone dehydratase gene from Ophiostoma floccosum restores the melanization and pathogenicity phenotypes of a melanin-deficient Colletotrichum lagenarium mutant

Scytalone dehydratase is involved in the production of fungal dihydroxynaphthalene (DHN) melanin. We have isolated and characterized OSD1, a gene encoding scytalone dehydratase from the sap-staining fungus Ophiostoma floccosum by PCR-based cloning. Sequence analysis suggests that the OSD1 gene encodes a protein of 216 amino acids with a molecular weight of 24.2 kDa that shows 51-70% sequence identity to other scytalone dehydratases. The cloned OSD1 contains two introns of 76 bp and 63 bp in length, and is the longest scytalone dehydratase gene sequence so far reported. Transformation of a DHN melanin-deficient, non-pathogenic, mutant of Colletotrichum lagenarium with the OSD1 gene restored melanin production and pathogenicity. The ability of the mutant to produce the OSD1 gene product was confirmed by RT-PCR analysis. These data show that the cloned OSD1 gene product can function in the DHN melanin biosynthetic pathway in C. lagenarium.

Migration of osteoblastic cells on various guided bone regeneration membranes

To evaluate the biological effects of guided bone regeneration (GBR) barrier materials on osteoblastic cell migration, migration of mouse osteoprogenitor cells (MC3T3-E1) was examined, in vitro, on various membranes. Eight commercially available GBR membranes - bovine type I collagen (BioMend; BM), porcine type I collagen (BioGide; BG), bovine type I atelocollagen (Tissue Guide; TG), polylactic acid (Epi-Guide; EG), co-polymer of polylactic acid and polyglycolic acid (Resolute; RL, Resolut XT; RL-XT), expanded polytetrafluoroethylene (e-PTFE; Gore Tex; GT) and co-polymer of cellulose acetate and nitrocellulose (Millipore filter; MP) - were tested. A 3x5 mm section of the membrane was fixed to the bottom of a culture dish with double-sided adhesive tape, and half of the membrane was closely covered by PARAFILM (American National Can) to leave an unexposed area for cell migration. The border between exposed and unexposed areas was marked as a baseline of cell migration. Membranes were then plated with 3 ml of cell suspension at an initial density of 1x105 cells/ml in alpha-MEM culture medium with 10% fetal bovine serum and ascorbic acid. After a 5-hour incubation, non-attached cells were completely washed out with phosphate buffered saline and the PARAFILM cover was removed. After 3 days cultivation, specimens were fixed with 10% buffered formalin and stained briefly with hematoxylin. The area of cell migration on a membrane was analyzed using a LA 500 Image Analysis System and migration area per unit length of the baseline (mm2/mm) was compared among membranes. Results demonstrated that cell migration was greater in the order: RL>RL-XT, BM, TG, MP>EG, BG. Membranes except for BG, EG and GT showed the migration rate equal to or higher than a plastic culture cover slip (Celldesk) (P<0.01) on which cells generally grow favorably. Only a small number of the cells attached to GT, and the net cell migration for the membrane could not be determined. These results indicate that GBR barrier materials per se may influence the process of bone regeneration in vivo through the effects of their presence on cell migration.

Molar root anatomy and management of furcation defects

BACKGROUND, AIMS

Furcally-involved teeth present unique challenges to the success of periodontal therapy. Anatomical and morphological complicating factors dictate modifications in treatment approaches used for managing these areas.

METHOD

Various treatment approaches are available for furcally-involved teeth, the choice of which depends on selected interdependent factors.

RESULTS

These factors, along with various approaches used in the treatment of furcally compromised teeth are discussed in this review, with particular emphasis on morphology, etiology, classification and diagnosis.

Effect of non-surgical periodontal therapy on C-telopeptide pyridinoline cross-links (ICTP) and interleukin-1 levels

BACKGROUND

Biochemical markers harvested from gingival crevicular fluid (GCF) may be useful to identify and predict periodontal disease progression and to monitor the response to treatment. C-telopeptide pyridinoline cross-links (ICTP), a host-derived breakdown product specific for bone, and interleukin-1beta (IL-1), a potent bone-resorptive cytokine, have been associated with periodontal tissue destruction. The aim of this study was to examine the effect of non-surgical periodontal therapy on GCF levels of ICTP and IL-1.

METHODS

Twenty-five chronic periodontitis subjects were monitored at 8 sites per subject at baseline prior to scaling and root planing and 1, 3, and 6 months after therapy. Four shallow (probing depths < 4 mm) and 4 deep (probing depths > or = 5 mm) sites were monitored for both marker levels and clinical parameters. GCF was collected for 30 seconds on paper strips, and levels of ICTP and IL-1 were determined using radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques, respectively. Clinical measurements included probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP).

RESULTS

Deep sites exhibited significantly (P<0.001) higher ICTP and IL-1 levels compared to shallow sites at all time intervals. ICTP demonstrated a stronger association to clinical parameters than IL-1 including a modest correlation (r = 0.40, P<0.001) between ICTP and attachment loss. Significant improvements in PD, CAL, and BOP were observed at 1, 3, and 6 months in all sites (P<0.01). However, non-surgical mechanical therapy did not significantly reduce ICTP and IL-1 levels over the 6-month period. Further examination of subjects based on smoking status revealed that ICTP levels were significantly reduced at 3 and 6 months and IL-1 levels reduced at 3 months among non-smokers only.

CONCLUSIONS

A single episode of non-surgical mechanical therapy did not significantly reduce biochemical markers associated with bone resorption in patients exhibiting chronic periodontitis. Future longitudinal studies are warranted to specifically evaluate the relationship between C-telopeptide pyridinoline cross-links and periodontal disease progression.