Molecular characterization of twenty polymorphic microsatellite markers in the polyploid fruit tree species Syzygium samarangense (Myrtaceae)

Syzygium samarangense (Blume) Merr. & Perry (wax apple) is an important commercial fruit tree in Southeast Asia. Here, microsatellite markers were developed to evaluate genetic diversity and distinguish cultivars in this species. In total, 161 microsatellite loci with sufficient flanking sequences to design primer sets were isolated from wax apple using a magnetic bead-enrichment method. Fifty-eight primer sets were designed based on the flanking sequences of each single sequence repeat (SSR) locus and were tested using 14 wax apple cultivars/lines. Twenty SSR loci were found to be polymorphic and transferable across the 14 wax apple cultivars/lines. The number of alleles and effective number of alleles detected per locus ranged from 4 to 12 and from 1.697 to 9.800, respectively. The expected heterozygosity ranged from 0.150 to 0.595 (mean = 0.414). Polymorphism information content values ranged from 0.502 to 0.866 (mean = 0.763). These new microsatellite loci will be of value for characterization of genetic diversity in wax apples and for the identification of cultivars.

Autointoxication mechanism ofOryza sativa : III. Effect of temperature on phytotoxin production during rice straw decomposition in soil

The phytotoxicity produced during decomposition of rice straw in soil was evaluated under both constant and changing temperature conditions. Bioassay tests showed that the aqueous extract from a soilstraw mixture after incubation at constant temperature was more than twice as phytotoxic as the extract from soil incubated alone. The phytotoxicity was highest at 20-25 ° C. Temperatures above 25 ° C enhanced rice straw decomposition and also degraded the phytotoxic substances more rapidly. After incubation of soil mixtures under changing temperature regimes in a phytotron, the phytotoxicy of the soil aqueous extracts increased in the following order: soil alone < soil + fertilizer < soil + straw < soil + straw + fertilizer. Growth inhibition of lettuce or rice seedlings was also at the highest at the temperature range of 25-30 ° C irrespective of the direction of temperature changes from either low to high or vice versa. Five phytotoxic phenolics,p-hydroxybenzoic, vanillic,p-coumaric, syringic, and ferulic acids, were obtained from both the aqueous extract and residue of the incubated soil samples and were quantitatively estimated by chromatography. The amount of phytotoxins found in various soil mixtures followed the same increasing order as that found by the seed bioassay test. Although no definite distribution pattern of the phenolics in the incubated soil samples can be attributed to temperature variations, the amount of the phenolics was likely higher in the samples incubated at 25 ° C than at either 15 ° C or 35 ° C. The quantity of toxins released during decomposition of rice straw in soil reached highest levels six weeks after incubation and gradually disappeared after twelve weeks.

Cervical granulocytic sarcoma: report of one case and review of the literature

Granulocytic sarcoma in the female genital tract generally has a poor prognosis. We report the case of a 52-year-old nonleukemic patient with relapsed granulocytic sarcoma at the vaginal stump after an 11-year complete remission from the uterine cervix. Magnetic resonance imaging of the pelvis showed a pear-shaped mass arising from the vagina mimicking a normal uterus. The unusual clinical presentation and the difficulties encountered in evaluation are presented. A review of the literature indicates that survival is better with multimodality management and in patients without leukemia.

'Big-eyed frog' sign on spatiotemporal image correlation (STIC) in the antenatal diagnosis of transposition of the great arteries

OBJECTIVE

To determine the value of simultaneous visualization of the cross-sectional view of both atrioventricular (AV) valves, the pulmonary artery and the aorta (en-face view of the AV valves and great vessels) in the identification of fetuses with transposition of the great arteries (TGA).

METHODS

This was a retrospective analysis of volume datasets obtained with the spatiotemporal image correlation (STIC) technique from 56 fetuses with and 30 fetuses without congenital heart defects. Volume datasets were reviewed offline to compare the en-face view of the AV valves and great vessels between fetuses with normal echocardiography and those with TGA.

RESULTS

The en-face view of both AV valves and great vessels in fetuses with TGA displayed the main pulmonary artery situated side-by-side with the aorta ('big-eyed frog' sign). In contrast, fetuses with normal hearts did not have this characteristic sonographic sign. This novel sonographic sign also helped to identify additional cases of TGA in 17 fetuses with complex heart defects.

CONCLUSION

The big-eyed frog sign may prove helpful in the prenatal diagnosis of TGA.

Hereditary angioedema: a Taiwanese family with a novel gene mutation

Hereditary angioedema (HAE) is an autosomal dominant disorder caused by a deficiency of C1 esterase inhibitor (C1-INH). Affected individuals have attacks of swelling involving almost any part of the body. We studied a family with 15 living members, including a 16-year-old girl who had 3 attacks of angioedema in 2 years. Her paternal uncle had died of asphyxiation during an attack 15 years previously. We analyzed the blood of each family member for C3, C4, and C1-INH levels and sequenced the SERPING1 (formerly C1NH) gene that codes for C1-INH. Six individuals had decreased serum levels of C4 and C1-INH, and they were all found to have a single nucleotide A deletion at codon 210 of the gene, 1210fsX210, a novel mutation that accounts for the HAE in this family.

Risk factors and characteristics of early-onset asthma in Taiwanese children

BACKGROUND AND PURPOSE

Early-onset asthma has been reported to be associated with a family history of allergy and exposure to environmental factors. This study was designed to evaluate the relationship between age of onset of asthma and genetic and environmental factors with asthma severity in Taiwanese children.

METHODS

A group of 352 children with asthma (220 males and 132 females), ranging in age from 5 to 15 years, were enrolled in this study. The subjects were divided into 2 groups: early-onset asthma (up to and including age 3) and late-onset asthma. General characteristics including family history of allergies and exposure to domestic pets and tobacco smoke were recorded. The subjects underwent pulmonary function testing and analysis of serum immunoglobulin E (IgE), eosinophil counts, and specific IgE for common allergens.

RESULTS

Early-onset asthma was present in 149 subjects and late-onset asthma in 203. Family history of allergies included a sibling with asthma or urticaria predisposed to early-onset asthma (asthma, p=0.034; urticaria, p=0.024). Food and milk allergen sensitization were more common in early-onset asthma (food allergens, p=0.025; milk, p=0.034). Children with early-onset asthma had higher eosinophil counts (p=0.041). However, there was no correlation between age at onset and pulmonary function testing, the levels of total IgE and IgE specific for Dermatophagoides pteronyssinus or Dermatophagoides farinae.

CONCLUSIONS

A history of asthma or urticaria in a sibling is a risk factor for early-onset asthma. A greater prevalence of food allergen sensitization and high eosinophil counts are characteristic of early-onset disease.

De novo mutation in the BTK gene of atypical X-linked agammaglobulinemia in a patient with recurrent pyoderma

BACKGROUND

X-linked agammaglobulinemia (XLA), characterized by a profound deficiency of all immunoglobulins and the absence of mature B cells, is caused by mutations in the gene encoding Bruton tyrosine kinase (BTK). Most patients have recurrent sinopulmonary infection. Infections usually occur in multiple locations across time, but single infection may be limited to one anatomic location.

OBJECTIVES

To report a case of atypical XLA with recurrent pyoderma and to observe the immunologic changes in the patient in 10 years.

METHODS

Immunologic investigations, skin wound culture, and molecular study with DNA sequencing were performed.

RESULTS

The patient was originally diagnosed as having common variable immunodeficiency disease because of the presence of circulating B cells (CD19+ B cells: 7%) at 11 years old. On further evaluation at the age of 20 years, flow cytometric analysis of lymphocytes showed only 0.4% B cells. The molecular study with DNA sequencing of the patient showed a point mutation in complementary DNA 1630 A>G(p.R544G) in the BTK gene, indicating that the patient has XLA. The mutation analysis of the BTK gene revealed a normal DNA sequence in the other family members.

CONCLUSIONS

This case is an important example of a possible presentation of XLA with a predominant skin manifestation, and it demonstrates that maintaining a high level of clinical suspicion is essential for the diagnosis of XLA in a child with recurrent pyoderma.

A randomized controlled trial of cetirizine plus pseudoephedrine versus loratadine plus pseudoephedrine for perennial allergic rhinitis

The purpose of this study was to compare the safety and efficacy of cetirizine plus pseudoephedrine (C+P) with loratadine plus pseudoephedrine (L+P) in the treatment of perennial allergic rhinitis. This was a double blind, randomized, parallel trial with an active control. Subjects aged 12 to 70 years with perennial allergic rhinitis for at least 2 years were enrolled and randomized to receive either of the active study medications plus a placebo resembling the other, twice daily for 4 weeks. Nasal total symptom scale (NTSS) including sneezing, rhinorrhea, nasal itching and nasal stuffiness is evaluated by subjects daily and at baseline, 2 weeks, and 4 weeks by the investigator as efficacy measurement. A total of 51 eligible patients were enrolled and 45 patients completed the treatment course. Both groups had significant reductions in NTSS after 4 weeks of treatment as assessed by the subjects, but there was no significant difference between the two groups (mean +/- SD) reduction of 4.25 +/- 2.45 with C+P vs. 3.52 +/- 2.41 with L+P, p = 0.215. As assessed by the investigator, sneezing was significantly better at 2 weeks (-1.13 vs. -0.52, p = 0.028) and nasal congestion at 4 weeks (-1.71 vs. -1.19, p = 0.031) in subjects treated with C+P compared to those treated with L+P. There were 37 treatment-related adverse events (5 in 4 subjects in the C+P group and 32 in 16 subjects in the L+P group). It was concluded that both cetirizine plus pseudoephedrine and loratadine plus pseudoephedrine are efficacious for perennial allergic rhinitis in Taiwanese subjects. Relief of sneezing and nasal congestion may be marginally better with the cetirizine preparation, which also seemed to be slightly better tolerated, although the incidence of side effects did not differ significantly.

Systemic anaphylaxis after the ingestion of pancake contaminated with the storage mite Blomia freemani

BACKGROUND

Systemic anaphylaxis after the ingestion of mite-contaminated food has rarely been reported.

OBJECTIVE

To describe an 8-year-old boy in whom systemic anaphylaxis developed shortly after the ingestion of pancakes prepared with commercial pancake flour.

METHODS

The patient underwent skin prick testing for house dust mites and with uncontaminated and mite-contaminated pancake flour. Specific IgE for mites and the main ingredients of the pancake flour were also evaluated, with titers for Der p 1, Der f 1, and Blo t 5 quantitated using immunochemical methods. A sample of pancake flour was examined microscopically for mites.

RESULTS

The patient had positive skin prick test results to contaminated pancake flour extract (1 g/5 mL), Dermatophagoides pteronyssinus, and Dermatophagoides farinae but a negative skin test response to uncontaminated pancake flour. The patient's serum specific IgE analysis was positive for antibodies to dust and storage mite allergens. There was no response, however, to the main ingredients of the pancake mix. Microscopic examination of the pancake flour revealed the storage mite Blomia freemani. Using an immunochemical assay, we found that the contaminated flour contained 5.4 microg/g of the allergen Blo t 5 but no Der p 1 or Der f 1.

CONCLUSIONS

This patient's anaphylactic episode was the result of ingestion of the storage mite B. freemani. To our knowledge, this is the first reported systemic hypersensitivity reaction caused by this mite anywhere in the world.

Deficiency of the Seventh Component of Complement in a Taiwanese Boy

Inherited complement deficiencies are rare, particularly those associated with late components of the complement cascade. We report a 5-year-4-month-old Taiwanese boy with systemic meningococcal infection who had undetectable CH50 level of < 6 U/mL (normal, 32.6-39.8 U/mL). Levels of C3, C4, C5, C6 and C8 were normal, but C7 was undetectable (< 5.8 mg/dL; reference, 55-85 mg/dL). The patient's sister was also C7-deficient (CH50 < 6 U/mL, C7 < 5.8 mg/dL). His father's CH50 was 25.9 U/mL and C7 was 27.8 mg/dL. His mother's CH50 was 31.2 U/mL and C7 was 22.7 mg/dL. His parents thus both had a partial complement deficiency, indicating an autosomal codominant inheritance pattern. Awareness of the possibility of late complement deficiency is important as they comprise a small percentage of patients who present with disseminated meningococcal disease or other serious infections caused by encapsulated organisms.

Hepatic venous stenosis in partial liver graft transplantation detected by color Doppler ultrasound before and after radiological interventional management

Hepatic outflow insufficiency remains one of the major complications causing postoperative graft failure especially among partial liver graft transplantations (PLT) including living donor liver transplantation (LDLT), reduced size liver transplantation (RLT), and split liver transplantation (SLT). These procedures are different from the whole liver graft transplantations (OLT), which include multiple vascular anastomoses. Color Doppler ultrasound (CDUS) was used to evaluate the hepatic venous outflow from grafts before and after radiological interventional management and to document treatment effects. From June 1994 to March 2003, our 136 cases of PLTs included 131 LDLTs, two RLTs, and three SLTs. Seven cases (six children and one adult) showed postoperative hepatic vein outflow obstruction and persistent massive ascites, as detected by color Doppler ultrasound (CDUS) and confirmed by interventional angiography. The CDUS showed a monophasic flat waveform with a relatively low hepatic vein average peak velocity (Va) in all cases (mean 11 cm/s). Successful interventional procedures included balloon dilatation in three cases and metallic stent replacement in four cases. CDUS was used with guidance during the procedure to confirm restoration of normal hepatic vein flow with a multiphasic waveform and an objective increase of average flow velocity (high to average 66 cm/s). Ascites disappeared dramatically after the procedure. In conclusion CDUS is the prime modality to diagnose and document a treatment response.

Purification and characterization of the 1.0 MDa CCR4-NOT complex identifies two novel components of the complex

The CCR4-NOT complex is an evolutionarily conserved, transcriptional regulatory complex that is involved in controlling mRNA initiation, elongation and degradation. The CCR4-NOT proteins from Saccharomyces cerevisiae exist in two complexes, 1.9x10(6) Da and 1.0x10(6) Da (1.0 MDa) in size, and individual components of these complexes display such disparate functions as binding to and restricting TFIID functions, contacting SAGA and contributing to mRNA deadenylation. As a first step in characterizing the functional roles of the 1.0 MDa complex, we have purified it to near homogeneity. Mass spectrometric analysis was subsequently used to identify all the components of the complex. The 1.0 MDa complex was found to contain CCR4, CAF1, NOT1-5 and two new proteins, CAF40 and CAF130. CAF130 and CAF40 are two unique yeast proteins, with CAF40 displaying extensive homology to proteins from other eukaryotes. Immunoprecipitation and gel filtration experiments confirmed that CAF130 and CAF40 are components of both of the 1.9 MDa and 1.0 MDa CCR4-NOT complexes. Biochemical analysis indicated that the CAF40 and CAF130 proteins bind to the NOT1 protein and exist in a location separate from the two other subsets of proteins in the complex: the CCR4 and CAF1 proteins, and the NOT2, NOT4 and NOT5 proteins. Moreover, CAF40 was able to interact with human NOT1, suggesting that human CAF40 would also be a component of the recently identified human CCR4-NOT complex. Analysis of caf40 and caf130 deletions indicated that they elicited phenotypes shared by defects in other CCR4-NOT genes. The distinct location of CAF40 and CAF130 and the evolutionary conservation of CAF40 implicate them in novel roles in the function of the CCR4-NOT complex.

Single imaging modality evaluation of living donors in liver transplantation: magnetic resonance imaging

BACKGROUND

Liver graft size, anatomy of the bile duct and the vascular inflow and outflow are essential for living related liver transplantation (LRLT). Preoperative delineation of those variations that would change the operative procedure to achieve a successful result especially in an emergency condition.

PURPOSE

Our aim was to develop a rapid and noninvasive imaging diagnostic method for the detection of anatomical variants that is mandatory for a safe operation when selecting potential liver transplant living donors. We used a different magnetic resonance (MR) imaging technique, which enabled to us to exploit the anatomical landmark of the liver, signal enhancement of blood flow in the abdomen, and the intrahepatic biliary routes inside the liver. Then, with the help of Advantage Window workstation reconstruction, the reconstructed single vascular or biliary systems were displaced in a three-dimensional fashion and the whole examination finished within 30 min.

METHODS

Modification of the standard MR technique was performed on a superconductive 1.5T whole body image scanner, MR arteriogaphy, venography, and cholangiography with three-dimensional reconstruction in evaluating the anatomy of the hepatic arteries, hepatic veins, portal venous system, bile ducts, and liver size in potential liver transplant living donors. These anatomical structures were compared with traditional imaging methods.

RESULTS

In all 38 cases, as well as delineation of the portal vein detail to the segmental level was satisfactorily obtained in this MR study. The images were well displayed in a three-dimensional fashion, which had good correlation with images from traditional imaging modalities and operative findings. In 86.8% cases, the MR arteriography was well matched with the celiac angiography. Of those 17 operative cases, estimation of liver volume was well correlated with the liver graft within 3.9-12.5% variation. In the major hepatic vein, we obtained 100% accuracy and 88.2% in the minor branches. Of 12 donors received intraoperative cholangiography during liver donation, good correlation of biliary anatomy was achieved. One donor was excluded from graft donation due to the complicated arterial supply to the left liver. According to the anatomical variation, surgical procedures in graft harvesting and anastomosis were readjusted and no major complications were found in those donors and all recipients survived after liver transplantation.

CONCLUSION

MR volumetry, venography, angiography, and cholangiography with three-dimensional reconstruction is sufficient for all major imaging evaluation. It may replace the traditional conventional catheter angiography, computed tomography, sonography and endoscopic retrograde cholangiography as a single investigation in the evaluation of the potential liver transplant donors. Angiography is only valuable in suboptimal cases and intraoperative cholangiography is only performed in biliary ductile variants.

Phylogeography of Kandelia candel in East Asiatic mangroves based on nucleotide variation of chloroplast and mitochondrial DNAs

Vivipary with precocious seedlings in mangrove plants was thought to be a hindrance to long-range dispersal. To examine the extent of seedling dispersal across oceans, we investigated the phylogeny and genetic structure among East Asiatic populations of Kandelia candel based on organelle DNAs. In total, three, 28 and seven haplotypes of the chloroplast DNA (cpDNA) atpB-rbcL spacer, cpDNA trnL-trnF spacer, and mitochondrial DNA (mtDNA) internal transcribed spacer (ITS) were identified, respectively, from 202 individuals. Three data sets suggested consistent phylogenies recovering two differentiated lineages corresponding to geographical regions, i.e. northern South-China-Sea + East-China-Sea region and southern South-China-Sea region (Sarawak). Phylogenetically, the Sarawak population was closely related to the Ranong population of western Peninsula Malaysia instead of other South-China-Sea populations, indicating its possible origin from the Indian Ocean Rim. No geographical subdivision was detected within the northern geographical region. An analysis of molecular variance (AMOVA) revealed low levels of genetic differentiation between and within mainland and island populations (phiCT = 0.015, phiSC = 0.037), indicating conspicuous long-distance seedling dispersal across oceans. Significant linkage disequilibrium excluded the possibility of recurrent homoplasious mutations as the major force causing phylogenetic discrepancy between mtDNA and the trnL-trnF spacer within the northern region. Instead, relative ages of alleles contributed to non-random chlorotype-mitotype associations and tree inconsistency. Widespread distribution and random associations (chi2 = 0.822, P = 0.189) of eight hypothetical ancestral cytotypes indicated the panmixis of populations of the northern geographical region as a whole. In contrast, rare and recently evolved alleles were restricted to marginal populations, revealing some preferential directional migration.

Organelle DNA phylogeography of Cycas taitungensis, a relict species in Taiwan

The phylogegraphic pattern of Cycas taitungensis, an endemic species with two remaining populations in Taiwan, was investigated based on genetic variability and phylogeny of the atpB-rbcL noncoding spacer of chloroplast DNA (cpDNA) and the ribosomal DNA (rDNA) internal transcribed spacer (ITS) of mitochondrial DNA (mtDNA). High levels of genetic variation at both organelle loci, due to frequent intramolecular recombination, and low levels of genetic differentiation were detected in the relict gymnosperm. The apportionment of genetic variation within and between populations agreed with a migrant-pool model, which describes a migratory pattern with colonists recruited from a random sample of earlier existing populations. Phylogenies obtained from cpDNA and mtDNA were discordant according to neighbour-joining analyses. In total four chlorotypes (clades I-IV) and five mitotypes (clades A-E) were identified based on minimum spanning networks of each locus. Significant linkage disequilibrium in mitotype-chlorotype associations excluded the possibility of the recurrent homoplasious mutations as the major force causing phylogenetic inconsistency. The most abundant chlorotype I was associated with all mitotypes and the most abundant mitotype C with all chlorotypes; no combinations of rare mitotypes with rare chlorotypes were found. According to nested clade analyses, such nonrandom associations may be ascribed to relative ages among alleles associated with the geological history through which cycads evolved. Nested in networks as interior nodes coupled with wide geographical distribution, the most dominant cytotypes of CI and EI may represent ancestral haplotypes of C. taitungensis with a possible long existence prior to the Pleistocene glacial maximum. In contrast, rare chlorotypes and mitotypes with restricted and patchy distribution may have relatively recent origins. Newly evolved genetic elements of mtDNA, with a low frequency, were likely to be associated with the dominant chlorotype, and vice versa, resulting in the nonrandom mitotype-chlorotype associations. Paraphyly of CI and EI cytotypes, leading to the low level of genetic differentiation between cycad populations, indicated a short period for isolation, which allowed low possibilities of the attainment of coalescence at polymorphic ancestral alleles.

Interventional radiologic procedures in liver transplantation

Postoperative biliary and vascular complications contribute significantly to morbidity and mortality in liver transplantation. Interventional radiologists are an integral part of the multidisciplinary team necessary for optimizing the management of these complications. During a 15-year period, 39 cadaveric and 25 living related liver transplantations were performed at the Chang Gung Memorial hospital, Taiwan. Of 64 liver transplant recipients, 9 (3 adult and 6 pediatric) underwent 13 interventional radiological procedures for the treatment of biliary sludge-casts (n = 2), bile duct occlusion or stenosis (n = 2), hepatic veins thrombosis (n = 1), hepatic veins stenosis (n = 1), portal vein stenosis with splenorenal shunting (n = 1), biloma (n = 1), and infected fluid collection or ascites (n = 4). Antegrade or retrograde interventional approach was used to successfully treat all biliary complications, and all percutaneous drainage procedures were effective in the control of intra-abdominal fluid collections. Portal vein stenosis was treated by balloon dilatation, and the associated splenorenal shunt was closed by metallic coil embolization via transhepatic catheterization of the portal vein. Hepatic vein stenosis was effectively treated by balloon dilatation and expandable metallic stent deployment via transfemoral and jugular venous approaches, respectively. Hepatic vein thrombosis was only partially lysed by transvenous streptokinase administration, and surgical thrombectomy was needed to achieve complete recanalization. The total success rate of the interventional procedures was 92 % with no procedure-related complications. The overall survival rate in this series is 89 %, and all patients who underwent living related liver transplantation maintain to date a 100 % survival rate. We can conclude that interventional radiological procedures are very useful for managing biliary and vascular complications after liver transplantation. These techniques provide a cure in most situations, thus obviating the need for further surgical intervention or re-transplantation.

Genetic evidence supports a role for the yeast CCR4-NOT complex in transcriptional elongation

The CCR4-NOT complex is involved in the regulation of gene expression both positively and negatively. The repressive effects of the complex appear to result in part from restricting TBP access to noncanonical TATAA binding sites presumably through interaction with multiple TAF proteins. We provide here genetic evidence that the CCR4-NOT complex also plays a role in transcriptional elongation. First, defects in CCR4-NOT components as well as overexpression of the NOT4 gene elicited 6-azauracil (6AU) and mycophenolic acid sensitivities, hallmarks of transcriptional elongation defects. A number of other transcription initiation factors known to interact with the CCR4-NOT complex did not elicit these phenotypes nor did defects in factors that reduced mRNA degradation and hence the recycling of NTPs. Second, deletion of ccr4 resulted in severe synthetic effects with mutations or deletions in the known elongation factors RPB2, TFIIS, and SPT16. Third, the ccr4 deletion displayed allele-specific interactions with rpb1 alleles that are thought to be important in the control of elongation. Finally, we found that a ccr4 deletion as well as overexpression of the NOT1 gene specifically suppressed the cold-sensitive phenotype associated with the spt5-242 allele. The only other known suppressors of this spt5-242 allele are factors involved in slowing transcriptional elongation. These genetic results are consistent with the model that the CCR4-NOT complex, in addition to its known effects on initiation, plays a role in aiding the elongation process.

Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of donor site

From August of 1995 through July of 1998, 38 free anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. The overall success rate was 97 percent. Among 38 anterolateral thigh flaps, four were elevated as cutaneous flaps based on the septocutaneous perforators. The other 34 were harvested as myocutaneous flaps including a cuff of vastus lateralis muscle (15 to 40 cm3), either because of bulk requirements (33 cases) or because of the absence of a septocutaneous perforator (one case). However, vastus lateralis muscle is the largest compartment of the quadriceps, which is the prime extensor of the knee. Losing a portion of the vastus lateralis muscle may affect knee stability. Objective functional assessments of the donor sites were performed at least 6 months postoperatively in 20 patients who had a cuff of vastus lateralis muscle incorporated as part of the myocutaneous flap; assessments were made using a kinetic communicator machine. The isometric power test of the ratios of quadriceps muscle at 30 and 60 degrees of flexion between donor and normal thighs revealed no significant difference (p > 0.05). The isokinetic peak torque ratio of the quadriceps and hamstring muscles, including concentric and eccentric contraction tests, showed no significant difference (p > 0.05), except the concentric contraction test of the quadriceps muscle, which revealed mild weakness of the donor thigh (p < 0.05). In summary, the functional impairment of the donor thighs was minimal after free anterolateral thigh myocutaneous flap transfer.

Characterization of CAF4 and CAF16 reveals a functional connection between the CCR4-NOT complex and a subset of SRB proteins of the RNA polymerase II holoenzyme

The CCR4-NOT transcriptional regulatory complex affects transcription both positively and negatively and consists of the following two complexes: a core 1 x 10(6) dalton (1 MDa) complex consisting of CCR4, CAF1, and the five NOT proteins and a larger, less defined 1.9-MDa complex. We report here the identification of two new factors that associate with the CCR4-NOT proteins as follows: CAF4, a WD40-containing protein, and CAF16, a putative ABC ATPase. Whereas neither CAF4 nor CAF16 was part of the core CCR4-NOT complex, both CAF16 and CAF4 appeared to be present in the 1.9-MDa complex. CAF4 also displayed physical interactions with multiple CCR4-NOT components and with DBF2, a likely component of the 1.9-MDa complex. In addition, both CAF4 and CAF16 were found to interact in a CCR4-dependent manner with SRB9, a component of the SRB complex that is part of the yeast RNA polymerase II holoenzyme. The three related SRB proteins, SRB9, SRB10, and SRB11, were found to interact with and to coimmunoprecipitate DBF2, CAF4, CCR4, NOT2, and NOT1. Defects in SRB9 and SRB10 also affected processes at the ADH2 locus known to be controlled by components of the CCR4-NOT complex; an srb9 mutation was shown to reduce ADH2 derepression and either an srb9 or srb10 allele suppressed spt10-enhanced expression of ADH2. In addition, srb9 and srb10 alleles increased ADR1(c)-dependent ADH2 expression; not4 and not5 deletions are the only other known defects that elicit this phenotype. These results suggest a close physical and functional association between components of the CCR4-NOT complexes and the SRB9, -10, and -11 components of the holoenzyme.

Biliary complications in living related liver transplantation

BACKGROUND

Biliary tract reconstruction has long been considered the Achilles' heel of liver transplantation as biliary complications can increase morbidity and mortality especially in partial liver graft transplantation.

METHODS

Thirty-four living related liver transplants were performed at Chang Gung Memorial Hospital in Kaohsiung for 33 children and 1 adolescent during a 5.5-year period. All potential donors underwent a detailed preoperative imaging study of the vascular and biliary anatomy, including three-dimensional helical computed tomographic cholangiography (n = 20), magnetic resonance cholangiography (n = 14), and intra-operative cholangiography (n = 31) before graft retrieval. All hepatic artery anastomoses were performed in the standard microsurgery fashion and their patency was confirmed intra-operatively using Doppler ultrasound.

RESULTS

The biliary complication rate was 8.8% (3/34), including multiple intrahepatic biliary stenosis of unknown origin (n = 1), bile leakage from the Roux-en-Y loop (n = 1), and a missed biliary radicle (n = 1) which were treated via interventional radiological and surgical procedures. The overall graft and patient survival rates were 100%.

CONCLUSION

The biliary complication rate in this series was low compared to those of other experienced centers. Complete study of the variations of intrahepatic duct ramification pre-and-intra-operatively provided adequate information on the appropriate transection plane. Furthermore, intra-operative Doppler ultrasound verification of vessel patency helps prevent vascular complications, which has been identified as a cause of biliary complications.

Significance of glutamate and dopamine neurons in the ventral pallidum in the expression of behavioral sensitization to amphetamine

To explore the significance of ventral pallidum (VP) during the amphetamine sensitization, we first investigated if there are neurochemical alterations in the VP during amphetamine withdrawal period. Chronic amphetamine-treated (5 mg/kg x 14 days) rats displayed an apparent locomotion sensitization as compared with saline controls when challenged with 2 mg/kg amphetamine at withdrawal days 10-14. A microdialysis analysis revealed that output of the dopamine metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, in the VP of amphetamine-sensitized rats increased approximately two-fold as compared to controls at both pre- and post-amphetamine challenge period. On the other hand, the in vivo glutamate output in the VP increased upon amphetamine challenge in the behaviorally sensitized rats, but not in the controls. To evaluate if drug manipulation in the VP would affect the behavioral sensitization, we treated both groups of rats with NMDA receptor antagonist, MK-801 (5 microg/microl for 5 days; bilateral) in the VP during withdrawal days 6-10. Animals were challenged with 2 mg/kg amphetamine at withdrawal day 11. The behavioral profile exhibited that MK-801 pre-treatment significantly blocked the locomotion hyperactivity in amphetamine-sensitized rats. Taken together, the current results suggest that the excitatory amino acid in the VP plays a significant role during the expression of behavioral sensitization to amphetamine.

Outflow tract reconstruction in living donor liver transplantation

BACKGROUND

Hepatic venous reconstruction is critical in living donor liver transplantation because outflow obstruction may lead to graft dysfunction or loss. We describe our experience and analyze outcomes with a technique of creating a single outflow tract using venoplasties of the graft and recipient hepatic veins.

PATIENTS AND METHODS

A retrospective study was done on 38 consecutive living donor liver transplants performed from June 1994 to March 2000. The grafts included 36 left-side grafts and 2 right-side grafts. Nine grafts had multiple hepatic veins and required a venoplasty of two or three hepatic veins to create a single outflow orifice. Triple recipient hepatic venoplasty was performed in 32 patients, double venoplasty in 5 and none in 1.

RESULTS

There were four cases of outflow obstruction, three occurring in patients with a double recipient venoplasty. Two of the problems were remedied intraoperatively by adjusting the position of the graft although two were structural in nature and required the insertion of expandable metallic vascular stents. All donors and recipients with their original grafts are alive at a mean follow-up period of 27 months.

CONCLUSION

A triple recipient venoplasty with a matching venoplasty of multiple graft hepatic veins to create a single wide outflow orifice is recommended in living donor liver transplantation using left side grafts.

Combined microvascular anastomosis: experimental and clinical experience

A short operative time and a high successful rate of microvascular anastomosis are the goals of many plastic surgeons. The authors present their experimental and clinical experience in microvascular anastomoses with the use of a combination of continuous suture and interrupted tie. Twenty rats were divided into two groups. The aorta and inferior vena cava were used for microvascular anastomoses. The vessels of 10 rats were repaired with conventional interrupted suture, and the vessels of the other 10 rats were repaired with combined anastomoses. A total of 150 clinical microvascular surgeries during the past 2 years are also presented, all of which were performed using the combined method. Microvascular anastomoses with the combined method were completed faster than when using the conventional interrupted method in experimental studies. Clinically, no direct microvascular anastomosis failed with the use of combined method. Microvascular anastomosis with the use of the combined continuous suture and interrupted tie resulted in satisfactory outcomes. This technique has the advantages of both interrupted and continuous methods, but not their shortcomings.

International sharing of split liver grafts in Asia: initial experience

The donor shortage problem is particularly serious in Asia and has markedly limited progress in liver transplantation. The increasing demand has, in fact, made it necessary to resort to living donor liver transplantation in both pediatric and adult recipients. Nevertheless, expanding the use of split liver allografts is yet another option to increase the supply. This has a wide potential application on a regional level because most liver transplant programs are still small and may have limited resources in terms of being able to do two transplants in one sitting. The first experience of overseas sharing of split liver grafts in Asia took place in January 1999. The graft was from a 35-yr-old donor from Kaohsiung, Taiwan, who sustained irreversible brain damage in a vehicular accident and had optimal conditions for multiorgan donation. The liver was split ex vivo and the left lateral segment was given to a 3-yr-old girl with biliary atresia at the Chang Gung Memorial Hospital. The extended right lobe split graft was transported to Hong Kong and transplanted into a 51-yr-old male patient with end-stage hepatitis C cirrhosis who was then in a state of acute failure with hepatorenal syndrome. Graft function was excellent in both recipients and the patient from Taiwan was discharged without any complications. Unfortunately, the Hong Kong recipient developed a cerebrovascular accident and required a reoperation for bile leakage from the cut surface of the liver in the early postoperative period. He has made a steady recovery since then; graft function has remained good and his kidneys have recovered. Both patients are currently alive and well 11 months post-transplant. This initial experience of overseas sharing of split liver grafts in Asia demonstrates its feasibility. It has a potentially wide applicability and could lead to the establishment of a formal organ-sharing network in the region. Established competence and mutual trust among the participating liver transplant teams would be essential in perpetuating such a graft-multiplying strategy on an organized basis.

Functional interaction of CCR4-NOT proteins with TATAA-binding protein (TBP) and its associated factors in yeast

The CCR4-NOT transcriptional regulatory complex affects expression of a number of genes both positively and negatively. We report here that components of the CCR4-NOT complex functionally and physically interact with TBP and TBP-associated factors. First, mutations in CCR4-NOT components suppressed the his4-912delta insertion in a manner similar to that observed for the defective TBP allele spt15-122. Second, using modified HIS3 promoter derivatives containing specific mutations within the TATA sequence, we found that the NOT proteins were general repressors that disrupt TBP function irrespective of the DNA sequence. Third, increasing the dosage of NOT1 specifically inhibited the ability of spt15-122 to suppress the his4-912delta insertion but did not affect the Spt- phenotype of spt3 or spt10 at this locus. Fourth, spt3, spt8, and spt15-21 alleles (all involved in affecting interaction of SPT3 with TBP) suppressed ccr4 and caf1 defects. Finally, we show that NOT2 and NOT5 can be immunoprecipitated by TBP. NOT5 was subsequently shown to associate with TBP and TAFs and this association was dependent on the integrity of TFIID. These genetic and physical interactions indicate that one role of the CCR4-NOT proteins is to inhibit functional TBP-DNA interactions, perhaps by interacting with and modulating the function of TFIID.

Clusterin may be involved in rat liver allograft tolerance

Little is known about the possible role of complement inhibitors on tolerance induced by liver allografts. Clusterin, which is a plasma glycoprotein, inhibits cytolytic membrane attack complex (MAC) of complement by binding to soluble C5b-7 complex. The role of clusterin in relation to the naturally achieved tolerance in a rat orthotopic liver transplantation (OLT) has not been investigated before. Here we determined the kinetics of clusterin expression at different post-transplantation time points in a tolerogenic model (DA-PVG) where rejection was naturally overcome without any immunosuppressive drugs in comparison with the syngenic OLT model (DA-DA). Peripheral blood and liver tissues were taken from OLT at various post-operative time points. A strong expression of soluble clusterin was observed on post-transplantation day 7, which occurred at the peak of the rejection in this tolerogenic OLT model. The expression of clusterin remained strong even after tolerance was achieved. The intensity of clusterin expression was much stronger when compared with the syngenic OLT (DA-DA) model after OLT. A strong expression of clusterin mRNA was also observed in the tolerogenic model on post-OLT day (POD) 7 and the expression persisted when compared with the syngenic model on post-OLT day 60. Our data have shown that the strongest levels of clusterin during the reaction phase in tolerogenic OLT may be involved in tolerance induction.

Repeated hypotensive episodes due to hepatic outflow obstruction during liver transplantation in adult patients

We report two cases of unusual repeated hypotension, decreased cardiac output, decreased mixed venous oxygen saturation, decreased central venous pressure, pulmonary artery pressure, and pulmonary wedge pressure after the completion of all vascular anastamoses of liver transplantation. These unstable hemodynamics appear to reflect a clinically relevant picture of hypovolemia. However, the real cause was partial hepatic outflow obstruction. The obstruction was suspected because hypotension was alleviated by elevating the full-sized liver graft ventrally and to the left. Doppler ultrasound examination confirmed that the flow velocity of the hepatic vein outflow was insufficient when the liver fell to its resting position in the right hepatic fossa. An additional side-to-side cavo-caval anastomosis resolved the problem in one patient, whereas the other required not only the additional anastomosis, but also application of a tissue expander filled with 770 mL normal saline beneath the liver to eliminate the obstruction. We emphasize that obstruction of the hepatic outflow causes only temporal hypovolemia because of a decrease of venous return and that treatment of this complication should be surgical intervention to relieve the obstruction. Blind resuscitation with fluids will not solve the problem and, in fact, may result in fluid overload with subsequent complications.

Within- and between-individual length heterogeneity of the rDNA-IGS in Miscanthus sinensis var. glaber (Poaceae): phylogenetic analyses

The variability in the intergenic spacer (IGS) region between 17S and 25S rRNA genes of ribosomal DNA (rDNA) gene family was surveyed in Miscanthus sinensis var. glaber. Length heterogeneity, with sizes from 1782 to 2212 base pairs, of the IGS resulted from the variation of copy numbers of the A and B subrepeats. These repeated elements were located upstream of the presumptive polymeraseII promoter, which was the region corresponding to the nontranscribed spacer (NTS). Length heterogeneity was detected both within and between individuals of Miscanthus sinensis var. glaber. Neighbor-joining analyses of repetitive A elements indicated that both unequal crossing-over and preferential conversion may have affected the hot-spot regions of the IGS in concert. Within-individual polymorphism and the reconstructed phylogeny suggested that interspecific hybridization has also contributed to length heterogeneity.

The CCR4 and CAF1 proteins of the CCR4-NOT complex are physically and functionally separated from NOT2, NOT4, and NOT5

The CCR4-NOT complex (1 mDa in size), consisting of the proteins CCR4, CAF1, and NOT1 to NOT5, regulates gene expression both positively and negatively and is distinct from other large transcriptional complexes in Saccharomyces cerevisiae such as SNF/SWI, TFIID, SAGA, and RNA polymerase II holoenzyme. The physical and genetic interactions between the components of the CCR4-NOT complex were investigated in order to gain insight into how this complex affects the expression of diverse genes and processes. The CAF1 protein was found to be absolutely required for CCR4 association with the NOT proteins, and CCR4 and CAF1, in turn, physically interacted with NOT1 through its central amino acid region from positions 667 to 1152. The NOT3, NOT4, and NOT5 proteins had no significant effect on the association of CCR4, CAF1, and NOT1 with each other. In contrast, the NOT2, NOT4, and NOT5 interacted with the C-terminal region (residues 1490 to 2108) of NOT1 in which NOT2 and NOT5 physically associated in the absence of CAF1, NOT3, and NOT4. These and other data indicate that the physical ordering of these proteins in the complex is CCR4-CAF1-NOT1-(NOT2, NOT5), with NOT4 and NOT3 more peripheral to NOT2 and NOT5. The physical separation of CCR4 and CAF1 from other components of the CCR4-NOT complex correlated with genetic analysis indicating partially separate functions for these two groups of proteins. ccr4 or caf1 deletion suppressed the increased 3-aminotriazole resistance phenotype conferred by not mutations, resulted in opposite effects on gene expression as compared to several not mutations, and resulted in a number of synthetic phenotypes in combination with not mutations. These results define the CCR4-NOT complex as consisting of at least two physically and functionally separated groups of proteins.

Plasma selenium levels and risk of hepatocellular carcinoma among men with chronic hepatitis virus infection

Both experimental and epidemiologic studies have linked a low dietary intake of selenium with an increased risk of cancer. The authors examined the association between plasma selenium levels and risk of hepatocellular carcinoma (HCC) among chronic carriers of hepatitis B and/or C virus in a cohort of 7,342 men in Taiwan who were recruited by personal interview and blood draw during 1988-1992. After these men were followed up for an average of 5.3 years, selenium levels in the stored plasma were measured by using hydride atomic absorption spectrometry for 69 incident HCC cases who were positive for hepatitis B surface antigen (HBsAg) and/or antibodies against hepatitis C virus (mostly HBsAg positive) and 139 matched, healthy controls who were HBsAg positive. Mean selenium levels were significantly lower in the HCC cases than in the HBsAg-positive controls (p = 0.01). Adjusted odds ratios of HCC for subjects in increasing quintiles of plasma selenium were 1.00, 0.52, 0.32, 0.19, and 0.62, respectively. The inverse association between plasma selenium levels and HCC was most striking among cigarette smokers and among subjects with low plasma levels of retinol or various carotenoids. There was no clear evidence for an interaction between selenium and alpha-tocopherol in relation to HCC risk.

Magnetic resonance of the hepatic veins with angular reconstruction: application in living-related liver transplantation

BACKGROUND

Preoperative mapping of the hepatic venous system of the partial liver graft is indispensable to the success of living-related liver transplantation. We assessed the accuracy of magnetic resonance (MR) venography with angular reconstruction in depicting the tributaries of the middle hepatic vein and left hepatic vein in the donors, which was essential in graft retrieval and venoplasty.

METHODS

Nineteen living-related liver transplantation donors underwent a pretransplantation survey, including sonography and MRI for hepatic venous evaluation. T1-weighted images were reconstructed manually, using the inferior vena cava as a fixed point for tilting to produce an oblique plane image where both the middle hepatic vein and left hepatic vein could be demonstrated draining into the inferior vena cava. The reconstructed images of the hepatic veins were compared with preoperative sonography, intraoperative sonography, and operative findings.

RESULTS

Preoperative sonography and MR findings correlated well with the operative findings in the major hepatic veins. The MR venography of the ramification of the hepatic veins has an accuracy of 93%, the sonography, 84%. Sonography is slightly inferior in the evaluation of the hepatic vein in segment 4 and the left superior hepatic vein, with an accuracy of 73% and 67%, respectively.

CONCLUSION

MR venography with angular reconstruction is accurate in depicting the complex distribution of the hepatic veins of the left liver, providing important information for decision making as to the cutting plane during graft retrieval and the method of venoplasty and anastomosis. Thus, unnecessary blood loss could be avoided and vascular complications could be prevented, as these conditions would be unacceptable for a healthy living donor. We propose that MR venography, a rapid and reliable technique, is an appropriate alternative examination or complementary modality to sonography in the pretransplantation evaluation of the living donor.

Contact leukomelanosis induced by the leaves of Piper betle L. (Piperaceae): a clinical and histopathologic survey

BACKGROUND

In April 1997, an unusual pigmentary disorder was noticed by dermatologists in Taiwan. All patients had a history of using facial dressings with steamed leaves of Piper betle L. (Piperaceae).

OBJECTIVE

Our purpose was to clarify the evolution and the origin of this unique leukomelanosis.

METHODS

Fifteen patients with an unusual pigmentary disorder, who visited our clinic in September and October 1997, were asked to complete a questionnaire designed to elicit the history related to the disorder. Eight of these 15 patients underwent skin biopsies: 6 on the mottled hyperpigmented area (group A) and 2 on the hypopigmented area (group B). All 8 specimens were prepared with hematoxylin-eosin, Masson-Fontana, and S-100 stains.

RESULTS

The results of the questionnaire revealed that these patients had all experienced a temporary erythematous reaction in the first few days of the use of the facial dressing, and 9 of them also complained of an accompanying stinging sensation. A bleaching effect became noticeable approximately 1 week to 1 month later. Eight patients reported that the hyperpigmentation and confetti-like hypopigmentation occurred after overexposure to the sun. In both groups, histopathologic examination revealed some melanophages in the dermis. Masson-Fontana staining of specimens from group A showed local interspersed depigmentation and hyperpigmentation in the basal epidermis and pigmentary incontinence in the dermis. This picture was different from the homogeneous depigmentation within basal epidermis in specimens from group B. In both groups, S-100 staining was negative for melanocytes in the depigmented area.

CONCLUSION

The clinical course and histopathologic findings suggest that the evolution of this pigmentary disorder can be divided into 3 stages. The first stage is the immediate bleaching stage, when an irritant reaction is usually conspicuous. The second stage consists of prominent hyperpigmentation visible both grossly and microscopically. The final stage is characterized by confetti-like depigmentation. It may be induced by chemicals in the betel leaves such as phenol, catechol, and benzene derivatives, perhaps through inhibition of melanin synthesis or melanocytotoxicity.

Plasma carotenoids, glutathione S-transferase M1 and T1 genetic polymorphisms, and risk of hepatocellular carcinoma: independent and interactive effects

This study was conducted to assess the role of carotenoid and glutathione S-transferase (GST) M1 and T1 genetic polymorphisms in the development of hepatocellular carcinoma (HCC). A total of 84 incident cases of HCC and 375 matched controls selected from a cohort of 7,342 men (4,841 chronic hepatitis B carriers and 2,501 noncarriers) who were recruited between 1988 and 1992 in Taiwan were studied. Neither GST M1/T1 polymorphisms nor plasma levels of various carotenoids were independently associated with HCC, but they modulated smoking- and/or drinking-related HCC risk. Cumulative exposure to tobacco smoke significantly increased HCC risk in a dose-dependent manner among subjects with low plasma beta-carotene levels (p for trend = 0.047) but not among those with high levels. A statistically significant effect of habitual alcohol drinking on HCC risk was observed only for those with low plasma levels of beta-carotene, alpha-carotene, or lycopene and for GST M1 null subjects. There was evidence suggesting an interaction between the GST M1/T1 genotype and certain carotenoids in HCC associated with smoking and drinking. The strongest effect of smoking and drinking was noted among GST M1 null subjects with low plasma levels of beta-carotene (smoking: adjusted odds ratio (OR) = 3.54, 95% confidence interval (CI) 1.06-11.83; drinking: OR = 8.28, 95% CI 2.40-28.61).

Jaw electromyographic activity induced by the application of algesic chemicals to the rat tooth pulp

The aim of this study was to determine if the application of mustard oil (MO), a small-fiber excitant and inflammatory irritant, or other algesic chemicals (capsaicin, CAP, and bradykinin, BK) to the rat maxillary molar tooth pulp induces electromyographic (EMG) activity of the masseter and digastric muscles, and also to determine if endogenous opioid mechanisms may be involved in any documented EMG changes. Application of MO to the tooth pulp induced a significant increase in EMG activity of the ipsilateral masseter up to 30 min. The application of mineral oil to the pulp or MO application to the pulp-extirpated tooth did not induce any significant EMG increases. The application of CAP or BK to the pulp in contrast had much weaker effects on EMG activity of the jaw muscles. CAP produced a small but prolonged increase in masseter EMG activity, and BK induced a short-lasting increase in digastric EMG activity. The systemic administration of the opiate antagonist naloxone significantly reactivated (i.e. rekindled) the EMG response evoked by MO application to the pulp. Naloxone did not produce any such significant rekindling effect on EMG activity following CAP, BK or mineral oil application to the pulp or following MO application to the pulp-extirpated tooth. The MO, BK and especially CAP groups showed histological evidence of vasodilatation and polymorphonuclear leukocyte infiltration in the pulp tissue and a significant increase in plasma extravasation of Evans Blue dye, whereas mineral oil did not induce these changes. These findings suggest that pulp afferent inputs to the central nervous system evoked by BK. CAP and especially MO may induce enhanced jaw muscle activity. In addition, the naloxone data suggest that an opioid suppresive mechanism may be induced by the pulpal afferent inputs evoked by MO, and may serve to limit the jaw muscle activity elicited by these inputs.

A p53 genetic polymorphism as a modulator of hepatocellular carcinoma risk in relation to chronic liver disease, familial tendency, and cigarette smoking in hepatitis B carriers

This study evaluated whether the codon 72 p53 polymorphism was related to hepatocellular carcinoma (HCC). Genotypes of p53 were determined in 80 incident cases of HCC and 328 controls nested in a cohort study of 4,841 male chronic hepatitis B carriers. No overall increase in HCC risk with the Pro variant allele of the p53 polymorphism was apparent. However, there were synergistic effects on HCC development for the Pro allele with chronic liver disease and family history of HCC in first-degree relatives. Compared with subjects without the Pro allele and chronic liver disease, the increase in HCC risk associated with chronic liver disease among those without the Pro allele was only threefold. Subjects with both chronic liver disease and the Pro allele were at an increased risk of 7.60 (95% CI = 2.28-25.31). When subjects without family history of HCC and the Pro allele were considered as the reference group, there was no apparent increased risk of HCC for those without the Pro allele who had family history of HCC. Among those with both factors, there was a significantly increased risk of 3.29 (95% CI = 1.10-9.85). Both cigarette smoking and glutathione S-transferase M1 genotype modified the risk of HCC associated with the p53 polymorphism. Significantly increased risk associated with the p53 genotype was observed only among smokers who were glutathione S-transferase-null (Pro/Pro vs. Arg/Arg: odds ratio = 6.46; 95% CI = 1.55-26.94). The p53 polymorphism also interacted with the cytochrome P450 1A1 and carotenoid levels in smoking-related hepatocarcinogenesis.

The influence of broadband noise on the precedence effect

This study examined the influence of background noise on the localization of lead-lag noise-burst pairs and on echo threshold for the same stimuli. Experiments were conducted in an anechoic chamber with a leading stimulus delivered from a loudspeaker at 45 degrees to the right of center and a lagging stimulus from 45 degrees left. Lead and lag stimuli were 4-ms bursts of Gaussian noise. In experiment 1, with lead and lag at equal levels and the lag delay fixed at 2 ms, the perceived location of the image produced by the lead-lag stimulus was estimated from subjects' left/right judgments relative to bursts from a "comparitor" loudspeaker whose position could be adjusted. In experiment 2, the dominance of the leading burst on perceived location was measured by determining the increase in level of the lagging burst necessary to produce an image estimated to be centered at 0 degree azimuth. Experiment 3 was concerned with echo threshold. Subjects reported whether or not they heard a sound in the vicinity of the lagging loudspeaker as the lag-burst delay was varied. In all three experiments, data were obtained for four to five stimulus levels in quiet and for three levels of background white noise from a loudspeaker at 180 degrees. The results revealed a substantial weakening effect of background noise on the precedence effect in experiments 2 and 3, and a nonsignificant effect in experiment 1.