Inheritance of genomic regions and genes associated with number of oocytes and embryos in Gir cattle through daughter design

Over the past decades, daughter designs, including genotyped sires and their genotyped daughters, have been used as an approach to identify QTL related to economic traits. The aim of this study was to identify genomic regions inherited by Gir sire families and genes associated with number of viable oocytes (VO), total number of oocytes (TO), and number of embryos (EMBR) based on a daughter design approach. In total, 15 Gir sire families were selected. The number of daughters per family ranged from 26 to 395, which were genotyped with different SNP panels and imputed to the Illumina BovineHD BeadChip (777K) and had phenotypes for oocyte and embryo production. Daughters had phenotypic data for VO, TO, and EMBR. The search for QTL was performed through GWAS based on GBLUP. The QTL were found for each trait among and within families based on the top 10 genomic windows with the greatest genetic variance. For EMBR, genomic windows identified among families were located on BTA4, BTA5, BTA6, BTA7, BTA8, BTA13, BTA16, and BTA17, and they were most frequent on BTA7 within families. For VO, genomic windows were located on BTA2, BTA4, BTA5, BTA7, BTA17, BTA21, BTA22, BTA23, and BTA27 among families, being most frequent on BTA8 within families. For TO, the top 10 genomic windows were identified on BTA2, BTA4, BTA5, BTA7, BTA17, BTA21, BTA22, BTA26, and BTA27, being most frequent on BTA7 and BTA8 within families. Considering all results, the greatest number of genomic windows was found on BTA7, where the VCAN, XRCC4, TRNAC-ACA, HAPLN1, and EDIL3 genes were identified in the common regions. In conclusion, 15 Gir sire families with 26 to 395 daughters per family with phenotypes for oocyte and embryo production helped to identify the inheritance of several genomic regions, especially on BTA7, where the EDIL3, HAPLN1, and VCAN candidate genes were associated with number of oocytes and embryos in Gir cattle families.

Pancreatic Adenocarcinoma: Unconventional Approaches for an Unconventional Disease

This review highlights current treatments, limitations, and pitfalls in the management of pancreatic cancer and discusses current research in novel targets and drug development to overcome these clinical challenges. We begin with a review of the clinical landscape of pancreatic cancer, including genetic and environmental risk factors, as well as limitations in disease diagnosis and prevention. We next discuss current treatment paradigms for pancreatic cancer and the shortcomings of targeted therapy in this disease. Targeting major driver mutations in pancreatic cancer, such as dysregulation in the KRAS and TGFβ signaling pathways, have failed to improve survival outcomes compared with nontargeted chemotherapy; thus, we describe new advances in therapy such as Ras-binding pocket inhibitors. We then review next-generation approaches in nanomedicine and drug delivery, focusing on preclinical advancements in novel optical probes, antibodies, small-molecule agents, and nucleic acids to improve surgical outcomes in resectable disease, augment current therapies, expand druggable targets, and minimize morbidity. We conclude by summarizing progress in current research, identifying areas for future exploration in drug development and nanotechnology, and discussing future prospects for management of this disease.

Laparoscopic Liver Resection: A South American Experience with 2887 Cases

BACKGROUND

Laparoscopic liver resections (LLR) have been increasingly performed in recent years. Most of the available evidence, however, comes from specialized centers in Asia, Europe and USA. Data from South America are limited and based on single-center experiences. To date, no multicenter studies evaluated the results of LLR in South America. The aim of this study was to evaluate the experience and results with LLR in South American centers.

METHODS

From February to November 2019, a survey about LLR was conducted in 61 hepatobiliary centers in South America, composed by 20 questions concerning demographic characteristics, surgical data, and perioperative results.

RESULTS

Fifty-one (83.6%) centers from seven different countries answered the survey. A total of 2887 LLR were performed, as follows: Argentina (928), Brazil (1326), Chile (322), Colombia (210), Paraguay (9), Peru (75), and Uruguay (8). The first program began in 1997; however, the majority (60.7%) started after 2010. The percentage of LLR over open resections was 28.4% (4.4-84%). Of the total, 76.5% were minor hepatectomies and 23.5% major, including 266 right hepatectomies and 343 left hepatectomies. The conversion rate was 9.7%, overall morbidity 13%, and mortality 0.7%.

CONCLUSIONS

This is the largest study assessing the dissemination and results of LLR in South America. It showed an increasing number of centers performing LLR with the promising perioperative results, aligned with other worldwide excellence centers.

Analysis of Defense-Related Gene Expression in Citrus Hybrids Infected by Xylella fastidiosa

Resistance to Xylella fastidiosa was evaluated in 264 hybrids of crosses between Murcott tangor (Citrus reticulata × Citrus sinensis) and Pera sweet orange (C. sinensis) under field conditions. Uninfected hybrids were grafted with buds collected from Pera sweet orange plants infected with X. fastidiosa, forming a plant with two scions (i.e., hybrid branches and Pera sweet orange branches). From these plants, we chose 10 genotypes with three biological replicates. We evaluated gene expression, bacterial multiplication, and citrus variegated chlorosis (CVC) symptom development in both scions. X. fastidiosa was not detected in most hybrid scions and none showed disease symptoms. In contrast, all Pera sweet orange scions were infected with X. fastidiosa and expressed symptoms of CVC. We quantified the expression of 12 defense-related genes by qPCR comparing resistant to susceptible scions. We suggest that some of these genes are involved in resistance of the hybrids to X. fastidiosa, since their expression was significantly higher in the resistant hybrid scions than in tolerant hybrids and scions originated from CVC symptomatic Pera sweet orange buds. However, we note that these data should be interpreted carefully, as the plant genotypes tested are related but necessarily distinct (hybrids of C. reticulata and C. sinensis, in relation to a C. sinensis control). A principal component analysis revealed a relationship between the expression of these genes and hybrid scions, and between scions that originated from infected buds and the presence of the bacteria and plant symptoms. Multiyear field trials are necessary to develop plant resistance to X. fastidiosa. While the experimental design used here had limitations, it allowed us to identify a set of genes potentially involved in Citrus sp. resistance to this pathogen. Future work on the role of these genes in plant defenses to X. fastidiosa infection is necessary to confirm their importance in the displayed resistance phenotype.

Differential expression of LHCGR and its isoforms is associated to the variability in superovulation responses of Gir cattle

The aim of this study was to evaluate the pattern of expression of LHCGR isoforms in Gir heifers characterized as good (10.3 ± 1.2 ova/embryos per flush, n = 5) or poor responders (1.1 ± 0.3 ova/embryos per flush, n = 5) to superovulation protocols. In both groups, an adapted ultrasound-guided follicular aspiration system was used to collect granulosa cells from 8 mm follicles formed either during a synchronized, non-stimulated follicular wave (no stimulation control, NS) or on the fourth day of a superovulation protocol (SOV) induced with 200 IU of pFSH. The recovered follicular fluid was centrifuged and granulosa cells were washed with NaCl 0.9% and kept in RNAlater^®. RNA extraction was performed using a commercial RNeasy Micro Kit and eluted samples were quantified and reverse transcribed using the commercial Superscript III kit. cDNA samples were amplified by real-time PCR using a primer to target LH/hCG receptor gene - not selective for LHCGR isoforms (total LHCGR) - and four sets of isoforms selective primers (S1, S10, S10 + 11, and S11). Analyses were performed using the REST software and expression levels are shown as mean ± SEM. Under physiological conditions (NS), poor responders had a higher expression of total LHCGR (4.9 ± 1.7 fold-change, P < 0.01) as well as isoforms S10, S11 and S10 + 11, compared to good responders. In both phenotypes, superovulation down-regulated total LHCGR expression (-0.5 ± 0.2 and -0.9 ± 0.0 for good and poor responders, respectively; P < 0.05). However, in poor responders the exogenous FSH treatment up-regulated the S10 (2.4 ± 2.0; P < 0.05), S10 + 11 (3.8 ± 3.2; P < 0.01), and S1 isoforms (1.8 ± 1.3; P < 0.05), compared to good responders We conclude that down-regulation of total LHCGR, associated to up-regulation of their inactive isoforms, may have compromised follicle development and thus contributed to the low efficiency of superovulation in heifers with a poor responder phenotype.

Red Sindhi cattle in Brazil: population structure and distribution

The Red Sindhi cattle breed was imported to Brazil in small numbers. Nowadays, the herds of this breed are distributed in the Northeast, Southeast and Midwest regions of the country. In this study, DNA samples of animals originating from 15 herds in the Northeast and Southeast regions have been analyzed to obtain the ancestry proportions, and to gain a better understanding of the current population structure of this breed in Brazil. Samples were genotyped using three different single nucleotide polymorphism (SNP) marker panels. Those markers have been used with the approach of unsupervised hierarchical clustering of individuals, and consequently, the ancestry of the population was divided into six different subpopulations. Three of those ancestry subpopulations were identified to be present in various different herds, while the other three were restricted to only one or two herds each. One of those herds has been kept isolated for more than 30 years, and it was identified to contain two almost exclusive subpopulations. To avoid important losses in the genetic diversity within the Red Sindhi breed in Brazil, we recommend the identification of superior sires from every subpopulation in the establishment of a breeding program for this breed.

Genome wide selection in Citrus breeding

Genome wide selection (GWS) is essential for the genetic improvement of perennial species such as Citrus because of its ability to increase gain per unit time and to enable the efficient selection of characteristics with low heritability. This study assessed GWS efficiency in a population of Citrus and compared it with selection based on phenotypic data. A total of 180 individual trees from a cross between Pera sweet orange (Citrus sinensis Osbeck) and Murcott tangor (Citrus sinensis Osbeck x Citrus reticulata Blanco) were evaluated for 10 characteristics related to fruit quality. The hybrids were genotyped using 5287 DArT_seq^TM (diversity arrays technology) molecular markers and their effects on phenotypes were predicted using the random regression - best linear unbiased predictor (rr-BLUP) method. The predictive ability, prediction bias, and accuracy of GWS were estimated to verify its effectiveness for phenotype prediction. The proportion of genetic variance explained by the markers was also computed. The heritability of the traits, as determined by markers, was 16-28%. The predictive ability of these markers ranged from 0.53 to 0.64, and the regression coefficients between predicted and observed phenotypes were close to unity. Over 35% of the genetic variance was accounted for by the markers. Accuracy estimates with GWS were lower than those obtained by phenotypic analysis; however, GWS was superior in terms of genetic gain per unit time. Thus, GWS may be useful for Citrus breeding as it can predict phenotypes early and accurately, and reduce the length of the selection cycle. This study demonstrates the feasibility of genomic selection in Citrus.

Total Laparoscopic Reversal ALPPS

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) allows R0 resection even for patients with extremely small future liver remnants. The ALPPS procedure was initially described for two-stage right trisectionectomy. Reversal ALPPS is a denomination in which the future liver remnant is the right posterior section of the liver.

PATIENT

A 42-year-old woman with colorectal metastases in all segments except segment 1 underwent chemotherapy with objective response and was referred for surgical treatment. The computed tomography (CT) scan showed a predominance of metastases in the left liver and in the right anterior section. The right posterior section had three metastases. The plan was to perform a laparoscopic reversal ALPPS (left portal vein ligation combined with in situ splitting in a two-stage left trisectionectomy).

TECHNIQUE

Three metastases in the right posterior section were resected, followed by liver partition and left portal vein ligature. The CT scan showed a 70 % increase in the future liver remnant. The second stage constituted left trisectionectomy. At laparoscopy after division of adhesions, the left Glissonian pedicle was divided with an endostapler. A stapler also was used to transect the left and middle hepatic veins, and the specimen was removed through a suprapubic incision. The operative times were respectively 5 and 3 h, and the patient was discharged on days 4 and 5, respectively. No blood transfusion or intensive care unit stay was necessary. At this writing, the patient shows no evidence of the disease 18 months after the procedure.

CONCLUSIONS

Reversal laparoscopic ALPPS is feasible and safe. Laparoscopy is useful for decreasing blood loss and optimizing visualization during liver transection.

Polymorphisms and alternative splicing of the luteinizing hormone receptor of dairy cattle

The aim of this study was to screen for variability in the luteinizing hormone/choriogonadotropin receptor (LHCGR) and to determine the occurrence of LHCGR mRNA isoforms in two dairy breeds of cattle. Granulosa cells from dominant ovarian follicles were recovered from 16 Gir and 16 Holstein cows, and total RNA was extracted. Complementary DNA was synthesized and PCR was used to generate amplicons for sequencing. Chromatograms were evaluated, and multiple sequences were aligned and analyzed for the presence of polymorphisms, allele frequency, polymorphic information content (PIC), and Hardy-Weinberg equilibrium (HWE). Twenty-one single nucleotide polymorphisms (SNPs) were identified in LH receptor mRNA. Seventeen SNPs were identified in Gir cattle (seven exclusively), and 14 were found in Holstein cattle (four exclusively). Seven of the 21 polymorphisms found did not alter which amino acid was translated. Eight SNPs caused a change to an amino acid in a different chemical group. Classification of SNPs according to PIC values identified 12 as being highly informative in Gir cattle and five in Holstein. Eight SNPs deviated from HWE in Gir compared with 11 in Holstein, and eight in both breeds. Two isoforms were also identified, one in exon 1, which lacks 30 nucleotides beginning at position 118, and the other in exon 10. Taken together, these data show that LHCGR in dairy cattle breeds has a high frequency of polymorphism and exists in multiple isoforms resulting from alternative splicing.

Pulp tissue response to Portland cement associated with different radio pacifying agents on pulpotomy of human primary molars

The objective of this research was to evaluate the response of Portland cement associated with different radio pacifying agents on pulp treatment of human primary teeth by clinical and radiographic exams and microscopic analysis. Thirty mandibular primary molars were randomly divided into the following groups: Group I - Portland cement; Group II - Portland cement with iodoform (Portland cement + CHI3 ); Group III - Portland cement with zirconium oxide (Portland cement + ZrO2 ); and treated by pulpotomy technique (removal of a portion of the pulp aiming to maintain the vitally of the remaining radicular pulp tissue using a therapeutic dressing). Clinical and radiographic evaluations were recorded at 6, 12 and 24 months follow-up. The teeth at the regular exfoliation period were extracted and processed for histological analysis. Data were tested using statistical analysis with a significance level of 5%. The microscopic findings were descriptively analysed. All treated teeth were clinically and radiographically successful at follow-up appointments. The microscopic analysis revealed positive response to pulp repair with hard tissue barrier formation and pulp calcification in the remaining roots of all available teeth. The findings of this study suggest that primary teeth pulp tissue exhibited satisfactory biological response to Portland cement associated with radio pacifying agents. However, further studies with long-term follow-up are needed to determine the safe clinical indication of this alternative material for pulp therapy of primary teeth.

Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence

Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants.

Resistance of Citrus and Related Genera to Diaphorina citri Kuwayama (Hemiptera: Liviidae)

The present study was developed to evaluate the resistance of the following genotypes of Citrus and related genera to this pest: 'Pera,' 'Natal', and 'Washington Navel' oranges (Citrus sinensis), 'Marsh Seedless' grapefruit (Citrus paradisi), hardy orange 'Rubidoux' (Poncirus trifoliata), kumquat (Fortunella margarita Swingle), citrumelo 'Swingle' (C. paradisi x P. trifoliata), and citrange 'Troyer' (P. trifoliata x C. sinensis). The experiments were performed in greenhouses with plants grafted onto 'Rangpur' lime (Citrus limonia) and placed individually in voile cages. The preference for oviposition in a no-choice test, and the effect of genotype were evaluated. The egg-adult cycle was monitored to determine the effect of genotype on the biology of the insect. Poncirus 'Rubidoux' was the least preferred genotype for oviposition; reduced number of eggs was also found to occur on citrange 'Troyer', and 'Marsh Seedless' was the genotype with the most eggs. No significant variation in the duration of the embryonic period was observed; however, a difference in the viability of eggs was found, with the lowest egg viabilities on 'Swingle.' Kumquat and 'Marsh Seedless' genotypes were correlated with increased durations of the nymphal phase, however, there was no difference in the survival of this phase. Fecundity of females on 'Troyer', 'Swingle', and kumquat was reduced. Considering all of the evaluated parameters, it was concluded that cultivars of sweet orange are the most susceptible genotypes to Diaphorina citri. Regarding oviposition, P. trifoliata 'Rubidoux' showed resistance of the antixenosis type.

A new tetra-primer ARMS-PCR for genotyping bovine kappa-casein polymorphisms

Kappa-casein (κ-casein) is one of the most abundant milk proteins. Its main function is to avoid the aggregation of casein micelles, keeping them, and therefore calcium phosphate, in pockets in solution. In bovines, a κ-casein functional polymorphism has been associated with fat, calcium, and protein milk contents and faster curd contraction in cheese production. Quicker curd contraction reduces the loss of milk solids, enhancing cheese yield. This polymorphism induces a double amino acid substitution (Thr136Ile and Ala148Asp). The polymorphism is normally detected by PCR-RFLP, which is a laborious method. An interesting methodological alternative is the tetra-primer amplification refractory mutation system PCR (tetra-primer ARMS-PCR). A tetra-primer ARMS-PCR for the detection of this κ-casein polymorphism has been described. However, specificity was not achieved, probably due to problems with primer design. We developed a new tetra-primer ARMS-PCR for the detection of the κ-casein polymorphism. This new method was validated in a double-blind test, by comparison with the results obtained for 50 Guzerá bulls formerly genotyped by PCR-RFLP. This new method achieved 100% sensitivity and specificity. We conclude that this method is a useful, cost-efficient alternative for the detection of functional κ-casein polymorphisms.

Genetic diversity of Vriesea cacuminis (Bromeliaceae): an endangered and endemic Brazilian species

Data about the genetic structure can help to understand the evolutionary process of natural populations as well as to drive strategies of conservation. Vriesea cacuminis, an endemic Brazilian Bromeliad, has been found in 2 areas of Minas Gerais State. One is a legal preservation unit (Ibitipoca State Park) and the other an unprotected area (Serra Negra). The 2 areas belong to the Mantiqueira Mountain Range Complex; both are characterized by steep relief with high altitudes and by heterogenic vegetation formed by a mosaic of rocky fields and forest fragments. According to International Union for Conservation of Nature criteria, V. cacuminis is designated as "vulnerable". We examined the genetic variability and population structure of 70 individuals (3 populations) of V. cacuminis, using 16 ISSR markers. Although V. cacuminis is considered a rare species, the estimated genetic diversity was found to be relatively high (Shannon index = 0.33; percentage of polymorphic bands = 87%). The populations were found not to be structured (AMOVA test, ΦST = 0.16), probably due to the cross-breeding. Based on Bayesian analysis, this species includes one cluster containing the populations from Ibitipoca State Park and another cluster including the population from Serra Negra. This information will help determine strategies to maintain the genetic variability of these populations.

Transcript profiling of expressed sequence tags from semimembranosus muscle of commercial and naturalized pig breeds

In general, genetic differences across different breeds of pig lead to variation in mature body size and slaughter age. The Commercial breeds Duroc and Large White and the local Brazilian breed Piau are ostensibly distinct in terms of growth and muscularity, commercial breeds are much leaner while local breeds grow much slower and are fat type pigs. However, the genetic factors that underlie such distinctions remain unclear. We used expressed sequence tags (ESTs) to characterize and compare transcript profiles in the semimembranosus muscle of these pig breeds. Our aim was to identify differences in breed-related gene expression that might influence growth performance and meat quality. We constructed three non-normalized cDNA libraries from semimembranosus muscle, using two samples from each one, of these three breeds; 6902 high-quality ESTs were obtained. Cluster analysis was performed and these sequences were clustered into 3670 unique sequences; 24.7% of the sequences were categorized as contigs and 75.3% of the sequences were singletons. Based on homology searches against the SwissProt protein database, we were able to assign a putative protein identity to only 1050 unique sequences. Among these, 58.5% were full-length protein sequences and 17.2% were pig-specific sequences. Muscle structural and cytoskeletal proteins, such as actin, and myosin, were the most abundant transcripts (16.7%) followed by those related to mitochondrial function (12.9%), and ribosomal proteins (12.4%). Furthermore, ESTs generated in this study provide a rich source for identification of novel genes and for the comparative analysis of gene expression patterns in divergent pig breeds.

High degree of genetic diversity among genotypes of the forage grass Brachiaria ruziziensis (Poaceae) detected with ISSR markers

The grasses of the genus Brachiaria account for 80% of the cultivated pastures in Brazil. Despite its importance for livestock production, little information is available for breeding purposes. Embrapa has a population of B. ruziziensis from different regions of Brazil, representing most of existing variability. This population was used to initiate an improvement program based on recurrent selection. In order to assist the genetic improvement program, we estimated the molecular variability among 93 genotypes of Embrapa's collection using ISSR (inter-simple sequence repeat) markers. DNA was extracted from the leaves. Twelve ISSR primers generated 89 polymorphic bands in the 93 genotypes. The number of bands identified by each primer ranged from two to 13, with a mean of 7.41. Cluster analysis revealed a clearly distinct group, containing most of the B. ruziziensis genotypes apart from the outgroup genotypes. Genetic similarity coefficients ranged from 0.0 to 0.95, with a mean of 0.50 and analysis of molecular variance indicated higher variation within (73.43%) than among species (26.57%). We conclude that there is a high genetic diversity among these B. ruziziensis genotypes, which could be explored by breeding programs.

Expressed sequenced tags profiling of resistant and susceptible Gyr x Holstein cattle infested with the tick Rhipicephalus (Boophilus) microplus

Tick resistance in cattle is mainly found in zebu (Bos indicus) animals, although it is also present in some taurine (B. taurus) breeds. In order to characterize functional genes involved in tick resistance/susceptibility in cattle, two cDNA libraries were generated using skin tissues of selected Holstein x Gyr animals. A total of 2700 high-quality reads from both resistant and susceptible cDNA were assembled into 458 sequences (contigs) and 834 singletons, with a mean size of 447.7 nucleotides. Assignment of homologous proteins by BLASTX revealed 790 (61.1%) and 300 (23.2%) hits in resistant and susceptible cDNA, respectively; 121 of these hits matched bovine proteins. A total of 502 (38.9%) unique sequences were found to have no significant homology with known sequences and were classified as novel sequences. In general, the most abundant sequences consisted of those coding for hypothetical proteins whose function had not yet been determined, in addition to ribosomal proteins, binding proteins and structural proteins, such as keratin and collagen. The most abundant protein found was collagen type III alpha, although ribosomal proteins accounted for half of the 40 most frequent hits. In addition, five matches within the top 40 best hits corresponded to immune response proteins. These sequences could be used for future studies on functional genomics of cattle tick resistance as well as for genomic sequencing projects.

Quantitative trait loci affecting lactose and total solids on chromosome 6 in Brazilian Gir dairy cattle

Fourteen Brazilian Gir sire families with 657 daughters were analyzed for quantitative trait loci (QTL) on chromosome 6 affecting lactose and total solids. Cows and sires were genotyped with 27 microsatellites with a mean spacing between markers of 4.9 cM. We used a 1% chromosome-wide threshold for QTL qualification. A QTL for lactose yield was found close to marker MNB66 in three families. A QTL for total solid yield was identified close to marker BMS2508 in three families. A QTL for lactose percentage, close to marker DIK1182, was identified in two families. A QTL for total solid percentage, close to marker MNB208, was identified in four families. These QTLs could be used for selection of animals in dairy production systems.

Genetic variability of an endangered Bromeliaceae species (Pitcairnia albiflos) from the Brazilian Atlantic rainforest

Pitcairnia albiflos is a Bromeliaceae species endemic to Brazil that has been included as data-deficient in the extinction risk list of Brazilian flora. We analyzed genetic variability in P. albiflos populations using RAPD markers to investigate population structure and reproductive mechanisms and also to evaluate the actual extinction risk level of this species. Leaves of 56 individuals of P. albiflos from three populations were collected: Urca Hill (UH, 20 individuals), Chacrinha State Park (CSP, 24 individuals) and Tijuca National Park (TNP, 12 individuals). The RAPD technique was effective in characterizing the genetic diversity in the P. albiflos populations since it was possible to differentiate the populations and to identify exclusive bands for at least two of them. Even if there is low genetic diversity among them (CSP-UH = 0.463; CSP-TNP = 0.440; UH-TNP = 0.524), the populations seem to be isolated according to the low genetic diversity observed within them (H(pop) CSP = 0.060; H(pop) UH = 0.042; H(pop) TNP = 0.130). This fact might be the result of clonal and self-reproduction predominance and also from environmental degradation around the collection areas. Consequently, it would be important to protect all populations both in situ and ex situ to prevent the decrease of genetic variability. The low genetic variability among individuals of the same population confirms the inclusion of this species as critically endangered in the risk list for Brazilian flora.

Video: intrahepatic Glissonian approach for pure laparoscopic right hemihepatectomy

AIM

To present a video of laparoscopic right hepatectomy using Glissonian technique. A new strategy for liver transection is presented. Liver is divided in three parts. The posterior part, containing short hepatic veins, is divided with stapler before liver transection. Anterior part is fully divided with harmonic scalpel, and the middle part, containing hepatic veins from segments 5 and 8, is the last part to be transected.

PATIENT AND METHOD

A 41-year-old woman with right-sided hepatolithiasis and choledocholithiasis was referred for surgical treatment. Patient was positioned in left lateral position. Four trocars were used. Operation began with division of liver ligaments, right liver mobilization, and exposure of the retrohepatic vena cava. Cholecystectomy was performed, followed by intrahepatic access to the right Glissonian pedicle (containing arterial, portal, and bile duct branches of segments 5-8). Two small incisions were performed around hilar plate according to specific anatomic landmarks. A vascular clamp was introduced into those incisions, resulting in ischemic delineation of right liver. Clamp was replaced by a vascular stapler, and stapler was fired. Liver parenchyma was divided by harmonic scalpel combined with vascular stapler. The specimen was extracted through suprapubic incision. Intraoperative cholangiography confirmed a 2-cm common bile duct stone which was immediately removed by endoscopy (endoscopic retrograde cholangiopancreatography, ERCP). Falciform ligament was sutured to maintain the liver in its original anatomical position, avoiding hepatic vein kinking, and abdominal cavity was drained.

RESULTS

Operative time was 180 min, with blood loss estimated at 50 ml, without need for transfusion. Postoperative recovery was uneventfully, and patient was discharged on the fourth postoperative day.

CONCLUSION

Laparoscopic intrahepatic Glissonian approach is feasible and is a useful technique for rapid and safe control of the right liver pedicle, facilitating laparoscopic right hemihepatectomy. The special strategy described may help laparoscopic surgeons to safely perform this challenging procedure.

Detection of Brevipalpus-transmitted viruses in their mite vectors by RT-PCR

The diagnosis of plant diseases caused by Brevipalpus-transmitted viruses (BrTVs) has been done through the analyses of symptoms, transmission electron microscopy, and RT-PCR of infected plant tissues. Here, we report the detection of Citrus leprosis virus C, Orchid fleck virus, Clerodendrum chlorotic spot virus and Solanum violaefolium ringspot virus in their viruliferous vectors Brevipalpus spp. using specific primer pairs for each of the viruses. The efficiency of virus transmission by Brevipalpus mites is low, so the detection of these pathogens in their vectors could constitute an important tool for studies involving virus-vector relationships, transmission, and monitoring the pathogen prior to the appearance of symptoms in the field.

Differential expression of genes in resistant versus susceptible Gyr x Holstein cattle challenged with the tick Rhipicephalus (Boophilus) microplus

The bovine tick Rhipicephalus (Boophilus) microplus causes major losses in cattle production systems in tropical regions. Bos indicus breeds are more resistant to ticks than B. taurus breeds. Resistance genes could be an alternative to control this parasite. We examined the pattern of gene expression of three calcium-binding-protein genes: translationally controlled tumor protein 1 (TPT1), allergen Bos d3 (S100A7), calcium channel protein transient receptor potential vanilloid 6 (TRPV6), and the cysteine proteinase inhibitor gene (CST6). These genes were selected from cDNA libraries prepared from skin biopsies taken from resistant and susceptible Gyr x Holstein F₂ animals. These biopsies were also used to study the expression level of these genes through real-time PCR analysis. The relative expression levels of the S100A7, TPT1, TRPV6, and CST6 genes were 2.01 ± 0.6, 1.32 ± 0.9, 1.53 ± 1.2, and 2.03 ± 0.7 times higher in the susceptible group, respectively. Skin lesion tissue from the susceptible animals showed significantly more mRNA transcripts of these genes in comparison with the resistant animals (P = 0.001). However, this hypersensitivity does not seem to protect the susceptible animals against tick infestation.

Genetic variability of Mahanarva sp (Hemiptera: Cercopidae) collected from different sites in Brazil

Spittlebugs are the leading cause of damage to tall grasses. Annual losses are estimated to reach 2.1 billion dollars in sugarcane crops and grazing land throughout the world. Correct identification of these species is difficult due to similarities in color, body size and male genitalia. Molecular markers have been useful in the identification and assessment of genetic diversity of many species. We investigated the genetic diversity of the spittlebug species Mahanarva fimbriolata, M. spectabilis and M. liturata and looked for markers that could aid in their identification. DNA from 34 spittlebug specimens, collected from six different regions of Brazil (Brasília, Campo Grande, Valença, Presidente Prudente, Juiz de Fora, and Porto Alegre), was analyzed with 29 RAPD primers, generating 501 polymorphic markers. High genetic variability was found among individuals M. fimbriolata (0.37), M. spectabilis (0.18) and M. liturata (0.69). Species-specific molecular RAPD markers were identified for each of the three species; these could be used as auxiliary tools for their correct identification.

Solid serous adenoma of the pancreas: an uncommon but important entity

Serous cystic neoplasms of the pancreas have currently five recognized subtypes: serous microcystic adenoma, serous oligocystic ill-demarcated adenoma, solid serous adenoma, von Hippel-Lindau-associated cystic neoplasm, and serous cystadenocarcinoma. Although these neoplasms are histologically similar they may differ in location, gross appearance and biology. Solid serous adenoma of the pancreas is by far the rarest subtype with only nine cases published thus far. In this review, we will discuss clinical features, imaging characteristics and histopathological findings, considering in particular (1) difficulties in preoperative diagnosis; and (2) relevant immunohistochemical analysis. After analyzing the literature, including one case from our Department, we can conclude that there is enough evidence to support that solid serous adenomas of the pancreas is a solid variant of serous cystadenomas. To date no malignant transformation is reported so far and therefore, to our knowledge, all patients are alive and without recurrence. Incidence is generally around seventh decade of life with no gender preference. Preoperative diagnosis is difficult to establish but magnetic resonance cholangiopancreatography may be useful. Given benign nature of this solid variant conservative surgery is recommended. It is definitively a rare entity but oncologic surgeons should be aware of this neoplasm in order to make a correct preoperative diagnosis that will ultimately result in more conservative surgeries.

Occlusal splints for treating sleep bruxism (tooth grinding)

BACKGROUND

Sleep bruxism is an oral activity characterised by teeth grinding or clenching during sleep. Several treatments for sleep bruxism have been proposed such as pharmacological, psychological, and dental.

OBJECTIVES

To evaluate the effectiveness of occlusal splints for the treatment of sleep bruxism with alternative interventions, placebo or no treatment.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group's Trials Register (to May 2007); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 1); MEDLINE (1966 to May 2007); EMBASE (1980 to May 2007); LILACS (1982 to May 2007); Biblioteca Brasileira de Odontologia (1982 to May 2007); Dissertation, Theses and Abstracts (1981 to May 2007); and handsearched abstracts of particular importance to this review. Additional reports were identified from the reference lists of retrieved reports and from article reviews about treating sleep bruxism. There were no language restrictions.

SELECTION CRITERIA

We selected randomised or quasi-randomised controlled trials (RCTs), in which splint therapy was compared concurrently to no treatment, other occlusal appliances, or any other intervention in participants with sleep bruxism.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out independently and in duplicate. Validity assessment of the included trials was carried out at the same time as data extraction. Discrepancies were discussed and a third review author consulted. The author of the primary study was contacted when necessary.

MAIN RESULTS

Thirty-two potentially relevant RCTs were identified. Twenty-four trials were excluded. Five RCTs were included. Occlusal splint was compared to: palatal splint, mandibular advancement device, transcutaneous electric nerve stimulation, and no treatment. There was just one common outcome (arousal index) which was combined in a meta-analysis. No statistically significant differences between the occlusal splint and control groups were found in the meta-analyses.

AUTHORS' CONCLUSIONS

There is not sufficient evidence to state that the occlusal splint is effective for treating sleep bruxism. Indication of its use is questionable with regard to sleep outcomes, but it may be that there is some benefit with regard to tooth wear. This systematic review suggests the need for further investigation in more controlled RCTs that pay attention to method of allocation, outcome assessment, large sample size, and sufficient duration of follow up. The study design must be parallel, in order to eliminate the bias provided by studies of cross-over type. A standardisation of the outcomes of the treatment of sleep bruxism should be established in the RCTs.

Mapping of quantitative trait loci controlling tick [Riphicephalus (Boophilus) microplus] resistance on bovine chromosomes 5, 7 and 14

Differences in domestication and selection processes have contributed to considerable phenotypic and genotypic differences between Bos taurus and Bos indicus cattle breeds. Of particular interest in tropical and subtropical production environments are those genetic differences between subspecies that underlie the phenotypic extremes in tolerance and susceptibility to parasite infection. In general, B. taurus cattle are more susceptible to ectoparasites than B. indicus cattle in tropical environments, and much of this difference is under genetic control. To identify genomic regions involved in tick resistance, we developed a B. taurus x B. indicus F(2) experimental population to map quantitative trait loci (QTL) for resistance to the Riphicephalus (Boophilus) microplus tick. About 300 individuals were measured for parasite load in two seasons (rainy and dry) and genotyped for 23 microsatellite markers covering chromosomes 5, 7 and 14. We mapped a suggestive chromosome-wide QTL for tick load in the rainy season (P < 0.05) on chromosome 5. For the dry season, suggestive (P < 0.10) chromosome-wide QTL were mapped on chromosomes 7 and 14. The additive effect of the QTL on chromosome 14 corresponds to 3.18% of the total observed phenotypic variance. Our QTL-mapping study has identified different genomic regions controlling tick resistance; these QTL were dependent upon the season in which the ticks were counted, suggesting that the QTL in question may depend on environmental factors.

Primers based on the rpf gene region provide improved detection of Xanthomonas axonopodis pv. citri in naturally and artificially infected citrus plants

AIMS

To have a PCR-based detection method for Xanthomonas axonopodis pv. citri (Xac) using primers designed in a specific region of its genome.

METHODS AND RESULTS

A Xac-specific region was identified inside the rpf gene cluster of strain IAPAR 306 in an analysis of its complete genomic sequence. Two primers were designed, Xac01 and Xac02, which, when used in a standard PCR assay, direct the amplification of a 581 bp fragment from DNA of strains belonging to Xac from different regions around the world including unusual American and Asian strains. This product was not observed when DNA from strains of the closely related X. a. aurantifolli and X. a. citrumelo were used as templates. Extracts prepared from 28 xanthomonads of other species, and epiphytic bacteria isolated from citrus also failed to produce products with these primers. Amplification was obtained from cells grown in vitro, from extracts of both fresh and dried citrus canker lesions and from washes of inoculated but asymptomatic leaf surfaces. In sensitivity tests, this PCR technique detected as few as 100 cells.

CONCLUSIONS

Primers Xac01 and Xac02 provide specific and sensitive detection of Xac in all citrus tissues where the pathogen is found.

SIGNIFICANCE AND IMPACT OF THE STUDY

This PCR-based diagnostic test is suitable for monitoring asymptomatic plants in areas where the bacteria is endemic, in plant quarantine and regulatory situations, and also for obtaining an accurate diagnosis in a very short time. These are important characteristics for any assay to be used for the management of citrus canker disease.

Complete nucleotide sequence, genomic organization and phylogenetic analysis of Citrus leprosis virus cytoplasmic type

The complete nucleotide sequence of the genomic RNA 1 (8745 nt) and RNA 2 (4986 nt) of Citrus leprosis virus cytoplasmic type (CiLV-C) was determined using cloned cDNA. RNA 1 contains two open reading frames (ORFs), which correspond to 286 and 29 kDa proteins. The 286 kDa protein is a polyprotein putatively involved in virus replication, which contains four conserved domains: methyltransferase, protease, helicase and polymerase. RNA 2 contains four ORFs corresponding to 15, 61, 32 and 24 kDa proteins, respectively. The 32 kDa protein is apparently involved in cell-to-cell movement of the virus, but none of the other putative proteins exhibit any conserved domain. The 5′ regions of the two genomic RNAs contain a ‘cap’ structure and poly(A) tails were identified in the 3′-terminals. Sequence analyses and searches for structural and non-structural protein similarities revealed conserved domains with members of the genera Furovirus, Bromovirus, Tobravirus and Tobamovirus, although phylogenetic analyses strongly suggest that CiLV-C is a member of a distinct, novel virus genus and family, and definitely demonstrate that it does not belong to the family Rhabdoviridae, as previously proposed. Based on these results it was proposed that Citrus leprosis virus be considered as the type member of a new genus of viruses, Cilevirus.

Association of BoLA-DRB3.2 alleles with tick (Boophilus microplus) resistance in cattle

Losses caused by bovine tick burdens in tropical countries have a tremendous economic impact on production systems. Besides reducing production, this parasite can cause death in the most susceptible animals. The use of commercial acaricides has been the major method of control, but their misuse has led to tick resistance to many chemicals. More recently, vaccines have been used in some countries without solving the problem completely. An alternative could be the development of resistant animals and the use of genetic markers and candidate genes that could help with the enormous task of selecting resistant animals. The bovine lymphocyte antigen genes (BoLA) have been shown to be associated with some parasitic infestations and disease incidence. Thus, the objective of the present study was to determine the association of BoLA-DRB3.2 alleles with tick resistance in cattle. The study was conducted on 231 F2 (Gyr x Holstein) animals that were artificially infested with 10,000 tick larvae. Log of tick count +1 was used as the dependent variable in a mixed animal model with allele substitution effects in addition to fixed effects of year and season at tick count, sex of calves, age of animal at tick count, hair type (short-straight, short-curl, long-straight, and long-curl), coat color (white, >75% white, 50- 75% white, and 25-50% white), and additive genetic, permanent environmental and residual effects as random. Females showed fewer ticks than males. Animals with short-straight hair were more resistant to tick infestation than animals with long-curl hair, and animals with whiter coat color also had fewer ticks. An association between BoLA alleles and lower tick number was found for alleles DRB3.2 *18, *20 and *27 at the 5% significance level. Also, one allele (DRB3.2*16) showed an association at the 10% level. Allele *27 was the most frequent in the population (30.7%), followed by alleles *16 (10.8%), *20 (8.7%) and *18 (2.4%). These results suggest that BoLA-DRB3.2 alleles could be used to help in the selection of animals resistant to tick infestation. However, further studies involving a larger population of cattle in combination with other BoLA genes may help to understand the mechanisms of resistance to parasites.

DGAT1 K232A polymorphism in Brazilian cattle breeds

Recent reports identified DGAT1 (EC 2.3.1.20) harboring a lysine to alanine substitution (K232A) as a candidate gene with a strong effect on milk production traits. Our objective was to estimate the frequency of the DGAT1 K232A polymorphism in the main Zebu and Taurine breeds in Brazil as well as in Zebu x Taurine crossbreds as a potential QTL for marker-assisted selection. Samples of 331 animals from the main Brazilian breeds, Nellore, Guzerat, Red Sindhi, Gyr, Holstein, and Gyr x Holstein F1 were genotyped for DGAT1 K232A polymorphism (A and K alleles) using the PCR-RFLP technique. The highest frequency of the A allele was found in the Holstein sample (73%) followed by Gyr x Holstein F1 (39%). Gyr and Red Sindhi showed low frequencies of A alleles (4 and 2.5%, respectively). The A allele was not found in the Nellore and Guzerat samples. Our results could be used to guide association studies between this locus and milk traits in these breeds.

Analysis of 16S rDNA Sequences from Citrus Huanglongbing Bacteria Reveal a Different "Ca. Liberibacter" Strain Associated with Citrus Disease in São Paulo

Citrus huanglongbing (HLB, ex greening) is one of the most serious and destructive citrus diseases in the world. It is caused by a phloem-limited and nonculturable bacterium, "Candidatus Liberibacter". The disease occurs in some Asian and African countries and recently has been reported in the state of São Paulo, Brazil. Analysis of the 16S ribosomal (r)DNA of the HLB bacteria from orchards in São Paulo revealed the presence of two distinct strains of "Ca. Liberibacter". One of them, named LSg1 (Liberibacter sequence group 1), was 100% identical to strains from Japan (GenBank accessions AB038369 and AB008366), the Asian forms of the bacteria. The other, LSg2, is genetically distant from the Asian (96.1 to 96.3% identity) and African (95.8 to 96.1% identity) strains. Comparison of the 16S rDNA sequences from the LSg2 and the Asian strain revealed the presence of INDELs and point mutations. Specific primers designed for this Brazilian Liberibacter strain revealed that it is more widely distributed throughout the São Paulo orchards compared with the LSg1 strain. The HLB symptoms caused by both strains are almost identical and, interestingly, both strains were found in the same sample, revealing mixed infection in a citrus plant.

First Report of the Causal Agent of Huanglongbing ("Candidatus Liberibacter asiaticus") in Brazil

Huanglongbing (ex-greening) disease is one of the most serious diseases of citrus. It is caused by the phloem-limited, gram-negative bacterium "Candidatus Liberibacter spp.". This bacterium is not well characterized mainly because it is still uncultured. There are two known strains, Asian ("Candidatus Liberibacter asiaticus") and African ("Candidatus Liberibacter africanus") that cause severe damage to citrus plants including twig dieback, decline, and death. Symptoms first appear as leaf mottling and chlorosis occurring in one shoot or sector of trees. Later, leaf symptoms resemble nutritional deficiencies (Zn, Ca, and N) that vary depending on the strains, with more severe symptoms caused by "Ca. L. asiaticus". The Asian strains are transmitted by the Asian citrus psyllid (AsCP), Diaphorina citri, which is present in Brazil. The bacterium has been detected in citrus plants in many geographic locations including China, Japan, Thailand, India, the Philippines, the Arabian Peninsula, and Africa. In 2004, plants showing Huanglongbing symptoms were observed in the Araraquara County, a central region of the State of Sao Paulo, the largest citrus-producing area in Brazil. To verify the presence of "Ca. L. spp." in these plants, leaf samples of sweet orange cvs. Hamlin and Valencia were used for DNA extraction and polymerase chain reaction amplification using the specific OI1 and Oi2c primers (1). Amplification of the 16S rDNA was positive for 2 (cvs. Hamlin and Valencia) of 10 analyzed plants. The amplified fragments were cloned and sequenced. The amplicons obtained from both plants showed the same sequence, which differed from "Ca. L. africanus", utilized as the positive control in the amplification experiment (27 divergent bases in 1,160). The sequences were used for BLAST searches, and the results showed identities ranging from 94.71 to 100% with "Ca. L. spp." sequences available at the National Center for Biotechnology Information database (on-line publication). The highest scores were obtained with "Ca. L. asiaticus sequences. These analyses confirmed the presence of such agent in the State of Sao Paulo. To our knowledge, this is the first report of "Ca. L. asiaticus" in Brazil as well as elsewhere in the Americas. The significance of this report relates to the potential damage that this pathogen could cause to the citrus industry in the largest citrus-producing country in the world. It remains unclear how and when the pathogen entered Brazil. Reference: (1) S. Jagoueix et al. Mol. Cell Probes 10:43, 1996.

Light/dark cycle-dependent metabolic changes in adipose tissue of pinealectomized rats

We investigated the effects of pinealectomy on adipose tissue metabolism at different times of day. Adult male Wistar rats were divided into two groups: pinealectomized and control (sham-operated). Eight weeks after surgery, the animals were killed at three different times (at 8.00 a.m., at 4.00 p.m. and 11.00 p.m.). We collected blood samples for glucose, insulin, corticosterone, and leptin determinations, and periepididymal adipocytes for in vitro insulin-stimulated glucose uptake, oxidation, and incorporation into lipids. Pinealectomy caused insulin resistance as measured by 2-deoxyglucose uptake (a fall of approximately 40 % in the maximally insulin-stimulated rates) accompanied by hypercorticosteronemia at the three time points investigated without changes in plasma insulin an or leptin levels. Furthermore, pinealectomy increased the insulin-induced glucose incorporation into lipids (77 %) at 4.00 p.m. and insulin-induced glucose oxidation in the morning and in the afternoon, while higher rates were observed in the evening and in the morning in control rats. In conclusion, cell responsiveness to insulin was differentially affected by pineal ablation and time of day, and persistent insulin resistance was obtained in pinealectomized rats. We hypothesize that pinealectomy exposes the animal to an inadequate match between energy requirements and fuel mobilization.

Comparative analyses of the complete genome sequences of Pierce's disease and citrus variegated chlorosis strains of Xylella fastidiosa

Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusually broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X. fastidiosa isolates that were expected to be genetically divergent. Here we report the genome sequence of X. fastidiosa (Temecula strain), isolated from a naturally infected grapevine with Pierce's disease (PD) in a wine-grape-growing region of California. Comparative analyses with a previously sequenced X. fastidiosa strain responsible for citrus variegated chlorosis (CVC) revealed that 98% of the PD X. fastidiosa Temecula genes are shared with the CVC X. fastidiosa strain 9a5c genes. Furthermore, the average amino acid identity of the open reading frames in the strains is 95.7%. Genomic differences are limited to phage-associated chromosomal rearrangements and deletions that also account for the strain-specific genes present in each genome. Genomic islands, one in each genome, were identified, and their presence in other X. fastidiosa strains was analyzed. We conclude that these two organisms have identical metabolic functions and are likely to use a common set of genes in plant colonization and pathogenesis, permitting convergence of functional genomic strategies.

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

Evaluation of guided bone regeneration and/or bone grafts in the treatment of ligature-induced peri-implantitis defects: a morphometric study in dogs

The goal of this study was to evaluate, morphometrically, hard-tissue healing following the treatment of ligature-induced peri-implantitis defects in dogs and guided bone regeneration and/or bone grafts. Five dogs were used, and the mandibular premolars were removed. Three months later, two titanium implants were installed on each side of the mandible, and after another 3 months, abutment connection was performed. Following abutment connection, experimental periimplantitis was induced by placing cotton ligatures in a submarginal position. Ligatures and abutments were removed after 1 month and the bony defects were randomly assigned to one of the following treatments: debridement (DE), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG), and debridement plus guided bone regeneration associated with mineralized bone graft (GBR/BG). The dogs were euthanatized after 5 months. Morphometric analysis did not reveal significant differences among the treatments neither with respect to the percentage of bone to implant contact (p = 0.996) nor to the bone area (p = 0.946) within the limits of the threads of the implant. Within the limits of this investigation, there is insufficient evidence to indicate that any of the treatments presented an improved response in dealing with bony defects resulting from peri-implantitis.

Histometric evaluation of the effect of nicotine administration on periodontal breakdown: an in vivo study

The present study investigated the effect of nicotine administration on periodontal breakdown resulting from ligature-induced periodontitis in rats. Twenty adult male Wistar rats were used. After anesthesia, a mandibular first molar was randomly assigned to receive a cotton ligature in the sulcular area while the contralateral tooth was left unligated. The animals were randomly assigned to one of the following treatments. of daily intraperitoneal injections: A - saline solution, B -0.37 mg of nicotine kg, C -0.57 mg of nicotine kg and D -0.73 mg of nicotine/kg. Thirty days later, the animals were sacrificed and the specimens routinely processed for serial decalcified sections. Statistical analysis (ANOVA) revealed greater bone loss (p<0.05) in the ligated teeth of animals which received nicotine (groups B/C D) than in the ligated teeth of animals which received saline solution (group A). In addition, a dose-dependent response was observed among the nicotine groups. A negative effect of nicotine was observed in the unligated teeth of the experimental groups (p<0.05). Therefore, daily administration of nicotine enhanced, in a dose-dependent manner, the effects of local factors in producing periodontal breakdown. Furthermore, the nicotine seemed to have a direct deleterious effect on the periodontal tissues.

Pancreatic head tumors with portal vein involvement: an alternative surgical approach

BACKGROUND/AIMS

One of the determining factors for the unresectability of pancreatic head tumors is the involvement of the portal venous system. Recent reports show that the resection of tumors with portal vein involvement has similar results to lesions with same stage without portal vein invasion. The aim of this study is to present a technique that allows the resection of portal vein segments without the use of grafts and with a shorter period of intraoperative venous occlusion.

METHODOLOGY

Fifteen patients with pancreatic head tumors and portal vein involvement were submitted to pancreaticoduodenectomy according to this technique. The main feature of the technique is starting the pancreatic dissection at the posterior aspect of the head of the pancreas. The superior mesenteric artery is completely dissected from the pancreatic tissues leaving the section of the pancreas and the resection of the portal vein to the last step.

RESULTS

Portal vein flow occlusion did not exceed 10 minutes. There were no major postoperative complications or mortality.

CONCLUSIONS

This maneuver allows an easier resection of the mobilized portal vein with a shorter period of venous clamping and reconstruction without the need of venous graft.

Differentiation of strains of Xylella fastidiosa by a variable number of tandem repeat analysis

Short sequence repeats (SSRs) with a potential variable number of tandem repeat (VNTR) loci were identified in the genome of the citrus pathogen Xylella fastidiosa and used for typing studies. Although mono- and dinucleotide repeats were absent, we found several intermediate-length 7-, 8-, and 9-nucleotide repeats, which we examined for allelic polymorphisms using PCR. Five genuine VNTR loci were highly polymorphic within a set of 27 X. fastidiosa strains from different hosts. The highest average Nei's measure of genetic diversity (H) estimated for VNTR loci was 0.51, compared to 0.17 derived from randomly amplified polymorphic DNA (RAPD) analysis. For citrus X. fastidiosa strains, some specific VNTR loci had a H value of 0.83, while the maximum value given by specific RAPD loci was 0.12. Our approach using VNTR markers provides a high-resolution tool for epidemiological, genetic, and ecological analysis of citrus-specific X. fastidiosa strains.

Absorbable versus nonabsorbable membranes and bone grafts in the treatment of ligature-induced peri-implantitis defects in dogs: a histometric investigation

The purpose of this study was to histometrically evaluate an absorbable collagen membrane (Bio-Gide) and a nonabsorbable polytetrafluoroethylene membrane (PTFE), associated with or without bone grafts, regarding "re-osseointegration" after treating ligature-induced peri-implantitis defects in dogs. All mandibular premolars were removed from five 2-year-old mongrel dogs. After 3 months of healing, 3 titanium implants were placed on each side of the mandible. Experimental peri-implantitis was induced with ligatures after abutment connection. Ligatures and abutments were removed after 1 month and the bone defects were randomly assigned to one of the following treatments; debridement alone (DB), debridement plus PTFE membrane associated with mineralized bone graft (Bio-Oss) (GBR+BG-I), debridement plus collagen membrane (Bio-Gide) associated with mineralized bone graft (GBR+BG-II), debridement plus PTFE membrane (GBR-I), debridement plus collagen membrane (GBR-II), or debridement plus mineralized-bone graft (BG). The dogs were sacrificed after 5 months. Data analysis did not reveal significant differences among the treatments regarding the percentage of bone-to-implant contact ("re-osseointegration") within the limits of the threads of the implant (P = .997). Thus, in the treatment of peri-implantitis, debridement alone as well as grafting alone had the same effect as did either membrane.

Clinical and microbiological evaluation of ligature-induced peri-implantitis and periodontitis in dogs

The purpose of this study was to evaluate the attachment loss around teeth and implants by clinical and microbiological analysis. The mandibular premolars were extracted in 5 mongrel dogs and, 3 months later, two titanium implants were installed on each side of the mandible and, after another 3 months, abutment connection was performed. Plaque control in the implants and maxillary premolars was maintained for two weeks prior to the start of the main experiment. On day 0 and 30 days after ligature placement, microbiological samples were obtained and relative attachment level was measured for the teeth and implants. The presence of Porphyromonas gingivalis, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Prevotella nigrescens was evaluated by polymerase chain reaction technique on day 0 and 30 days after ligature placement. None of the above bacteria were detected on day 0. Thirty days after ligature placement, P. gingivalis was present in 95% and 85% and B. forsythus was present in 80% and 85% of the implants and teeth sites, respectively. Statistical analysis (one-way RM-ANOVA) showed a significant difference (P<0.01) between pre- and post-induction measurements around teeth and implants. However, there was no significant difference (P=0.41) in the rate of attachment loss, between periodontitis and peri-implantitis. It can be concluded that: (1) P. gingivalis and B. forsythus were strongly associated with induced peri-implantitis and periodontitis, and (2) induced peri-implantitis and periodontitis presented a similar rate of attachment loss.

Lack of evidence for superantigen activity of Toxoplasma gondii towards human T cells

Toxoplasma gondii is an obligatory intracellular parasite whose life cycle may include man as an intermediate host. More than 500 million people are infected with this parasite worldwide. It has been previously reported that T. gondii contains a superantigen activity. The purpose of the present study was to determine if the putative superantigen activity of T. gondii would manifest towards human T cells. Peripheral blood mononuclear cells (PBMC) from individuals with no previous contact with the parasite were evaluated for proliferation as well as specific Vbeta expansion after exposure to Toxoplasma antigens. Likewise, PBMC from individuals with the congenital infection were evaluated for putative Vbeta family deletions in their T cell repertoire. We also evaluated, over a period of one year, the PBMC proliferation pattern in response to Toxoplasma antigens in patients with recently acquired infection. Some degree of proliferation in response to T. gondii was observed in the PBMC from individuals never exposed to the parasite, accompanied by specific Vbeta expansion, suggesting a superantigen effect. However, we found no specific deletion of Vbeta (or Valpha) families in the blood of congenitally infected individuals. Furthermore, PBMC from recently infected individuals followed up over a period of one year did not present a reduction of the Vbeta families that were originally expanded in response to the parasite antigens. Taken together, our data suggest that T. gondii does not have a strong superantigen activity on human T cells.

Clinical study of guided bone regeneration and/or bone grafts in the treatment of ligature-induced peri-implantitis defects in dogs

This study evaluated, by clinical analysis, the hard tissue response following treatment of ligature-induced peri-implantitis defects in 5 dogs. The mandibular premolars were removed from both sides of the jaw. After 3 months of healing, two titanium implants were placed on each side of the mandible. Following abutment connection, 3 months later, experimental peri-implantitis was induced by the placement of cotton ligatures in a submarginal position. Ligatures and abutments were removed after one month and the bony defects were randomly assigned to one of the following treatments: debridement (DE), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG) and debridement plus guided bone regeneration associated with mineralized bone graft (GBR + BG). The peri-implant bone defects were clinically measured before and 5 months post-treatment. Results showed a higher percentage of vertical bone fill for GBR + BG (27.77 +/- 14.07) followed by GBR (21.78 +/- 16.19), BG (21.26 +/- 6.87), DE (14.03 +/- 5.6). However, there were no statistically significant differences between any of the treatments proposed (one way repeated measures analysis of variance, P = 0.265).

Histometric evaluation of bone regeneration around immediate implants partially in contact with bone: a pilot study in dogs

Bone regeneration was evaluated around immediate implants partially in contact with bone, with or without the concurrent application of a combination of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-1). Mandibular premolars were removed, and the implant osteotomies were prepared; a uniform circumferential gap was prepared 1.25 mm beyond the width of the implant bed in the coronal half. Twelve implants (8.5 x 3.75 mm) were inserted in six dogs. Before insertion, an implant received a single application of 5 micrograms/mL of PDGF and IGF-1 delivered in 0.10 mL of 4% methylcellulose gel or 0.10 mL of 4% methylcellulose gel only as a control. To label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, 15, 30, and 45 days after implant insertion Three and 8 weeks after implant insertion undecalcified sections were obtained, and the degree of bone to implant contact, the bone area, and the intensity of bone labeling were measured into the limits of the eight most coronal threads of the implant (four threads on each side of each implant). The results showed a greater extension of bone-to-implant contact, a larger percentage of bone area, and greater intensity of bone labeling for test versus control implants (P < .01). Within the limits of the present study, it was concluded that the combination of PDGF/IGF-1 might be an alternative for enhancing bone healing around implants partially in contact with bone.

Platelet-derived growth factor/insulin-like growth factor-1 combination and bone regeneration around implants placed into extraction sockets: a histometric study in dogs

This study evaluated, by histometric analysis, the wound healing process of bone around implants placed into extraction sockets with or without the concurrent application of a combination of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-1). Mandibular premolars were removed, and 32 implants were inserted in eight dogs. Before insertion, two implants received a single application of 5 micrograms/mL of PDGF and IGF-1 delivered in 0.10 mL of 4% methylcellulose gel or 0.10 mL of 4% methylcellulose gel only as a control. To label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, 15, 30, 45, 60, and 75 days after implant insertion. Three, 8, and 12 weeks after implant insertion, undecalcified sections were obtained, and the degree of bone contact with the implant surface, the bone area, and the intensity of bone labeling were measured into the limits of the threads of the implant. Greater extension of bone/implant contact (paired t test, P < .05) was observed in test (22.4% +/- 13.7%) than in control (17.2% +/- 13.6%) implants at 3 weeks. One-way ANOVA revealed a higher intensity of bone labeling (P < .05) at 3 weeks than at 12 weeks (127.8 +/- 42.59 and 56.7 +/- 26.34, gray scale values) for test implants. Within the limits of the present study, it was concluded that the combination of PDGF/IGF-I actively took part in the initial phase of bone repair.

Hereditary gingival fibromatosis: report of three cases

Three cases of generalized and severe HGF in young patients of the same family without other features are reported. The purpose of this article is to present documented cases and discuss the identification, treatment, and control of the disease. The histopathological characteristics of HGF are emphasized.