[Analysis of the clinical predictive value of lactate on the prognosis of patients with acute-on-chronic liver failure combined with infection].

Objective: To explore the predictive value of lactic acid for the adverse prognostic outcomes in patients with acute-on-chronic liver failure combined with infection. Methods: A retrospective analysis was conducted on the clinical data of 208 cases of ACLF combined with infection who were hospitalized from January 2014 to March 2016. Patients were divided into a survival group (n = 83) and a mortality group (n = 125) according to the results of a 90-day follow-up. The clinical data were statistically analyzed between the two groups. Multivariate logistic regression with two categorical variables was used to analyze the independent risk factors for 90-day disease mortality and establish a new prediction model. The receiver operating characteristic curve (ROC curve) was used to evaluate the predictive value of lactic acid, the MELD score, the MELD-Na score, lactic acid combined with the MELD score, lactic acid combined with the MELD-Na score, and the new model. Results: The 90-day mortality rate of 208 cases of ACLF combined with infection was 60.1%. There were statistically significant differences in white blood cell count, neutrophil count, total bilirubin (TBil), serum creatinine (Cr), blood urea nitrogen (BUN), blood ammonia, the international normalized ratio (INR), lactic acid (LAC), procalcitonin, the MELD score, the MELD-Na score, hepatic encephalopathy (HE), acute kidney injury (AKI), and bleeding between the two groups. Multivariate logistic regression analysis showed that TBil, INR, LAC, HE, and bleeding were independent risk factors for 90-day mortality in patients with ACLF combined with infection. After the establishment of MELD-LAC, MELD-Na-LAC, and a new prediction model, the ROC curve revealed that the AUC (95% confidence interval) of MELD-LAC and MELD-Na LAC were 0.819 (0.759 ~ 0.870) and 0.838 (0.780 ~ 0.886), respectively, and was superior than the MELD score [0.766 (0.702 ~ 0.823)] and MELD-Na score [0.788 (0.726 ~ 0.843)], with P < 0.05, while the new model had an AUC of 0.924, the sensitivity of 83.9%, specificity of 89.9%, and accuracy of 87.8%, which was higher than LAC, MELD score, MELD-Na score, MELD-LAC, and MELD-Na-LAC (P < 0.01). Conclusion: Lactic acid is an independent risk factor for mortality in patients with ACLF combined with infection, and it improves the clinical predictive value of MELD and MELD-Na for the prognosis of mortality.

[Relationship between etiology and morphological classification of benign central airway stenosis and its prognosis].

Objectives: To analyze the relationship between etiology and morphological classification of benign central airway stenosis and its prognosis. Methods: We performed a retrospective study of the medical records of 453 patients initially diagnosed with benign airway stenosis at Department of Respiratory Diseases in Beijing Tiantan Hospital affiliated to Capital Medical University from January 2003 to October 2019. Of 453 patients, 260 were male. The age of the study population was 12-86(44.0±24.5) years. Results: Among the 453 patients diagnosed with benign central airway stenosis, 161 case (35.5%, including 113 post-tracheostomy tracheal stenosis and 48 post-intubation tracheal stenosis) were iatrogenic; 88 cases were from benign tumors (19.4%), 77 cases from tracheal or bronchial tuberculosis (17.0%), 71 case from tracheal foreign bodies (15.7%). Disease causes varied among different gender or age groups. The main type of stenosis was structural stenosis, of which 241 cases (53.2%) were intra-luminal and 183 cases (40.4%) were scar contracture type. The site of stenosis showed a certain relationship with the causes of stenosis. The stenosis degree was mainly from grade 2 to grade 4 (76.4%), and the length was mainly within 3 cm (84.8%). Single factor analysis on the relationship between disease cause, morphological classification and prognosis of benign central airway stenosis showed statistically better prognosis in groups that were caused by benign tumor, intraductal stenosis or stenosis that were 3-4 in degree and 1-2 degree in length. Conclusion: The common causes of central airway stenosis included iatrogenic stenosis, benign tumor, tracheal or bronchial tuberculosis and tracheal foreign bodies. Benign airway stenosis with different disease causes and morphological classification had different prognosis after bronchoscopic interventional treatment. Clinicians should know the disease causes, morphological characterization and risk factors for benign airway stenosis for earlier diagnosis, treatment or prevention.

[Validation and modification of AJCC 8th edition staging system for hepatocellular carcinoma--analysis based on SEER database].

Objective: To assess the accuracy of the American Joint Committee on Cancer (AJCC) 8th edition staging system for hepatocellular carcinoma (HCC) and to make an appropriate modification. Methods: Data of patients diagnosed with HCC who underwent surgery were extracted from 2004 to 2015 within the SEER database. Overall survival (OS) and disease-specific survival (DSS) of patients were analyzed. Results: A total of 7 911 patients were included and there were 2 117 females and 5 794 males. The male-to-female ratio was 1.00: 0.36. There were 4 050 patients older than 60 years old. Tumor size ranged from 24 to 65 mm. Tumors with single lobes (80.8%) or single lesions (62.8%) were more common. There were 230 cases and 2 052 cases received radiotherapy and chemotherapy, accounting for 2.9% and 25.9%, respectively. The median follow-up was 42 months. Analysis of the 8th edition of AJCC staging system showed that the survival curves of ⅣA stage and ⅢA stage intersected in both OS and DSS, and the differences were not statistically significant between them (both P>0.05). Analysis of patients in subgroup of ⅣA stage showed that there was no statistically significant difference in the four groups of T1N1M0/T2N0M0, T2N1M0/T3N0M0, T3N1M0/T4N0-1M0 and T3N1M0/T1-4N0-1M1 (all P>0.05). Therefore, the modified 8th edition of the AJCC staging system was proposed after retaining the definition of T/N/M in the old edition: ⅠA and ⅠB stages were retained; ⅣA stage was split: T1N1M0 was included in Ⅱ stage, T2N1M0 in Ⅲ stage, and Ⅳ stage included T3N1M0, T4N0-1M0 and T1-4N0-1M1. Cox proportional risk regression analysis of the modified 8th edition of the AJCC staging showed that significant differences were observed among the four groups, with ⅠB/ⅠA (HR=1.462, 95%CI:1.294-1.651), Ⅱ/ⅠB (HR=1.091, 95%CI:1.003-1.186), Ⅲ/Ⅱ (HR=2.034, 95%CI: 1.793-2.307) and Ⅲ/Ⅳ (HR=1.374, 95%CI: 1.192-1.583) for OS, respectively. The similar findings were seen in DSS, with ⅠB/ⅠA (HR=2.007, 95%CI:1.671-2.411), Ⅱ/ⅠB (HR=1.140, 95%CI:1.023-1.271), Ⅲ/Ⅱ (HR=2.344, 95%CI: 2.018-2.724) and Ⅲ/Ⅳ (HR=1.391, 95%CI:1.180-1.639), respectively. Conclusion: The modified AJCC 8th edition staging system could predict the survival outcome of HCC more accurately.

[Clinical features and imaging analysis of primary bone lymphoma of the jaw].

Objective: To investigate the clinical characteristics and imaging manifestations of primary bone lymphoma (PBL) located in the jaw. Methods: Clinical data of 14 PBL patients admitted to The First Affiliated Hospital of Zhengzhou University from January 2014 to April 2019 were retrospectively analyzed, which including age, gender, location, chief complaint, laboratory test, imaging manifestations and so on. Results: Among the 14 PBL patients, 10 were male and 4 were female. Age range from 4 to 79 years, median age was 56 years old. There were 6 cases involved maxillary, 7 cases involved mandible and 1 case involved mandible and maxillary simultaneously. Twelve patients were admitted with local mass as the chief complaint, 3 had a history of toothache, 4 had loosen tooth and 2 had numbness of lips and cheeks. Two cases of oral mass with mucosal surface ulcer or abscess formation. One case complained of fever, night sweats and other systemic symptoms. The imaging findings showed 8 cases of osteolytic lesions, 1 case of sclerosis, 4 cases of mixed lesions and 1 case of cystic lesions. One case had periosteum reaction. In 12 cases, there was an obvious mass, which was characterized by the large soft-tissue mass and marrow changes were associated with surprisingly little cortical destruction. Conclusions: PBL is more common in middle aged male. The upper and lower jaw bones can be involved. Clinical and imaging manifestations lack characteristics, and common dental or periodontal symptoms such as toothache, tooth loosening, and paresthesia may occur. However, the imaging characteristics of large soft tissue masses with small degree of bone destruction can be used as an important basis for the differential diagnosis of osteomyelitis, squamous cell carcinoma, osteosarcoma and other diseases.

Risk factors for death from hand-foot-mouth disease: a meta-analysis.

In recent years, outbreaks of hand-foot-mouth disease (HFMD) in China, Singapore and other Western Pacific Region, involving millions of children, have become a big threat to public health. This study aimed to quantitatively assess all qualified studies and identify the risk factors for HFMD death. A systematic search of the databases PubMed, Medline, Embase and the Cochrane Library was performed. Study heterogeneity and publication bias were estimated. Seven case-control studies involving 1641 participants (634 died and 1007 survived) were included in the meta-analysis. Human enterovirus 71 infection, male, age ⩽3 years, vomiting, cyanosis, convulsion, duration of fever ⩾3 days, atypical rashes and abdominal distention were not significantly related to HFMD death (P ⩽ 0.05). Lethargy (odds ratio (OR) = 6.62; 95% CI 3.61-12.14; I2 = 0%; P < 0.0001), pneumonoedema/pneumorrhagia (OR = 4.09; 95% CI 2.44-6.87; I2 = 0%; P < 0.0001), seizures (OR = 6.85; 95% CI 2.37-19.74; I2 = 0%; P = 0.0004), dyspnoea (OR = 8.24; 95% CI 2.05-33.19; I2 = 83%; P = 0.003) and coma (OR = 3.76; 95% CI 1.85-7.67; I2 = 0%; P = 0.0003) were significantly associated with HFMD death, which were risk factors for HFMD death.

[A study of bacterial distribution and drug resistance in skin and soft tissue infection].

Objective: To investigate pathogenic bacteria and drug resistance in the patients with skin and soft tissue infection in order to provide the scientific evidences for clinical reasonable use of antibiotics. Methods: A retrospective analysis was performed on patients with skin and soft tissue infections in Department of Dermatology, Peking University Third Hospital from January 2012 to December 2017. Pus, secretions, skin lesions, urine, throat swabs, and alveolar lavage fluid were collected for bacterial culture, bacterial species were identified by VITEK2 Compact system and BD-Bruker MALDI Biotyper system. Drug resistance was detected by K-B agar diffusion method recommended by CLSI. Results: A total of 392 strains of bacteria were isolated from 327 patients distributed in 21 genus and 56 species, of which 225 were gram-positive cocci (57.40%), 114 were gram-negative rods (29.08%), 46 were gram-positive rods (11.73%), and 7 were gram-negative cocci (1.79%). The top 3 bacteria were Staphylococcus aureus 91(23.21%), Staphylococcus epidermidis 42 (10.71%), and Pseudomonas aeruginosa 24 (6.12%). Staphylococcus had a high rate of resistance to penicillin and erythromycin (>50%). Gram-negative rods were resistant to ampicillin (86.1%), and also had certain resistance to most second-generation and some third-generation cephalosporin (about 50%). There was no significant change in the drug resistance rate of MRSA compared to MSSA. Only the resistance rate to tetracycline was statistically different (P<0.05). Conclusion: The emergence of drug-resistant strains is an important factor leading to refractory infections. There are a wide range of pathogenic bacteria species among the skin and soft tissue infection patients, and antimicrobial drugs should be chosen wisely according to drug sensitivity.

Comparative studies on testis, epididymis and serum hormone concentrations in foxes, and hybrids during the pre-breeding period.

Silver fox and blue fox belong to different genera, and the hybrid males are reproductively sterile. In the present study, there was a comparison of testicular and epididymal morphology and serum hormone concentrations among silver foxes, blue foxes, and the hybrids during the pre-breeding period, using 20 male silver foxes, 20 male blue foxes, 15 male HSBs (silver fox male × blue fox female hybrids) and 15 male HBSs (blue fox male × silver fox female hybrids), respectively. Hybrids had a smaller diameter of seminiferous tubules than pure-species males, and testes of hybrid males did not differ in mean size and relative weight from pure-species males. There were many Sertoli cells and spermatogenic cells in silver foxes and blue foxes, while numbers of spermatogonia and primary spermatocytes were less with no secondary spermatocytes in the hybrids. Furthermore, mean serum testosterone and estradiol concentrations in the hybrids were less, and FSH, LH, and PRL were greater than that in silver foxes and blue foxes (P < 0.05), suggesting that lesser concentrations of testosterone and estradiol and greater concentrations of FSH, LH and prolactin can inhibit the completion of spermatogenesis during the pre-breeding period. The results indicate that fox hybrid sterility may result from failures at the early stages of spermatogenesis.

[Clinical characteristics of allergic rhinitis allergen spectrum in Gannan area].

Objective:To study the clinical features of common allergens in patients with allergic rhinitis in Gannan area and provide reference for the prevention，diagnosis and treatment of allergic rhinitis with regional character.MethodThe clinical data of 363 patients who were newly diagnosed with allergic rhinitis and given allergen skin prick test（skin prick test，SPT）at our department from August 2012 to May 2016 were analyzed retrospectively.SPSS 180 was used to ananlyze the data.Result:Two hundred and fifty-two cases of allergen skin prick test were positive.The positive rates of allergens were 86.90% of house dust mites，86.11% of dust mites，51.19% of cockroach，14.29% of hair fungus，4.76% of crab meat and 3.17% of shrimp.The positive rate of various allergens in the children group was 93.24% for dust mites，91.89% for house dust mites，44.59% for cockroach，8.11% for crab meat，6.76% for shrimp，and 1.35% for hair fungus.The difference in positive rate of allergens among different age groups was statistically significant（P<0.01），among which the highest was 2 to 14 years old，which was 90.24%；the lowest was ＞44 to 74 years old，which was 31.70%.The difference in positive rates of allergens among different occupations was statistically significant（P<0.01），among which the highest was 86.45% for students，and the lowest was 45.24% for those without employment.There was no significant difference in the positive rate of allergens between different seasons.ConclusionThe most common allergens in Gangnan area are house dust mites，dust mites cockroache and scrab meat.Patients with allergic rhinitis are more common with multiple allergens.Age and occupation are also factors affecting the positive rate of allergens.

Circulating levels of autoantibodies against L1-cell adhesion molecule as a potential diagnostic biomarker in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a common malignant disease worldwide, especially in China. We aimed to determine the level of autoantibodies against L1CAM in patients with ESCC. METHODS: Levels of circulating autoantibodies against L1CAM antigens were determined by an enzyme-linked immunosorbent assay in cohort 1 (191 patients with ESCC and 94 normal controls) and validated in cohort 2 (47 patients with ESCC and 47 normal controls). Receiver-operating characteristics were employed to calculate diagnostic accuracy. Cumulative survival time was calculated by the Kaplan-Meier method and analyzed by the log-rank test. RESULTS: In cohorts 1 and 2, levels of autoantibodies against L1CAM were all significantly higher in sera of patients with ESCC compared to normal controls (P < 0.05). Detection of autoantibodies against L1CAM provided a sensitivity of 26.2%, a specificity of 90.4%, and an area under the curve (AUC) of 0.603 (95% CI 0.535-0.672) in diagnosing ESCC in cohort 1, and a sensitivity of 27.7%, a specificity of 91.5%, and an AUC of 0.628 (95% CI 0.516-0.741). Similar results were observed in the diagnosis of early stage ESCC (25.2% sensitivity, 90.4% specificity, and an AUC of 0.611 (95% CI 0.533-0.689) in cohort 1, and 33.3% sensitivity, 91.5% specificity, and an AUC of 0.636 (95% CI 0.439-0.832) in cohort 2). Moreover, positive rates of autoantibodies against L1CAM had no statistical correlation with clinical outcome of ESCC (P > 0.05). CONCLUSIONS: Our results suggest that circulating autoantibodies against L1CAM is a potential biomarker for the early detection of ESCC.

[Mechanism research progress of miRNA in laryngeal carcinoma].

MiRNA(miR) is a non-coding small RNA of 18 to 24 nucleotides in length.By pairing with 3'UTR of its target mRNA molecule, miRNA regulateS the target mRNA molecule in the translation level or directly lead to its degradation. Each miRNA may target several to several hundred mRNAs, of which 30% of the mRNA is regulated by miRNAs. Some studies have shown that miRNA expression disorders play an important role in the development and progression of various tumors and may be the ideal target for tumor therapy. It has been shown that abnormal expression of RNA (miRNA) plays an important role in the occurrence and development of laryngeal cancer. Wang Ping found 47 kinds of miRNA expression abnormalities in laryngeal cancer tissue with microarray chip detection, that of which high expression were 23 kinds and low expression were 24 kinds. MiRNAs that are abnormally expressed in laryngeal squamous cell carcinoma are expected to be a new marker for early diagnosis of laryngeal cancer. In this review, we summarized the progress in recent three years on the association of miRNA and the biological behaviors of laryngeal cancer.

Development and characterization of microsatellite loci in Excentrodendron hsienmu (Chun & How) H.T. Chang& R.H. Miau.

Microsatellite markers were isolated using dual-suppression-PCR for the endangered species Excentrodendron hsienmu (Tiliaceae) to evaluate the genetic diversity and population structure of this species. A total of 11 polymorphic microsatellite loci were characterized in E. hsienmu. The number of alleles per locus ranged from 2 to 9, with an average of 5.27. The expected heterozygosity value ranged from 0.053 to 0.780, with an average of 0.568 and the observed heterozygosity value ranged from 0 to 0.595, with an average of 0.268. The polymorphic information content value ranged from 0.051 to 0.740, with an average of 0.521. These newly designed markers will be of great potential significance and profound influence in future research related to the genetic diversity, population structure, and patterns of gene flow of this species, which will contribute to the implementation of conservation and management strategies for this species.

Characterization and identification of streptococci from golden pompano in China.

Streptococcal infections cause significant mortality and high economic losses in the fish farm industry worldwide, including in the culture of golden pompano Trachinotus ovatus L., a species gaining popularity in China. A total of 9 streptococcal strains were isolated from cage-cultured diseased golden pompano in Beihai, Zhanjing, and Shenzhen, China, between 2012 and 2014. Conventional and rapid identification systems were used to determine that the isolates were Streptococcus agalactiae, S. iniae, and S. dysgalactiae subsp. dysgalactiae. All isolates were gram-positive cocci cells in pairs or short-chain, non-motile, catalase negative, α or ß hemolytic cocci. The results of multiplex PCR assays and 16S rRNA BLAST analysis also showed that the ß hemolytic strains were S. agalactiae and S. iniae and the α hemolytic strain was S. dysgalactiae subsp. dysgalactiae, respectively. Pathogenicity assays revealed that S. agalactiae (lethal dose [LD50]: 6.38 × 10(4) CFU ml(-1)) was more virulent for golden pompano than S. iniae (LD50: 1.47 × 10(7) CFU ml(-1)) and S. dysgalactiae subsp. dysgalactiae (LD50: 2.57 × 10(6) CFU ml(-1)) when they were challenged by intraperiotoneal (i.p.) injection. The results of antibiotic susceptibility showed that all strains were extremely susceptible to cefradine, erythromycin, and cefotaxime but resistant to gentamicin, penicillin G, novobiocin, neomycin, ciprofloxacin, roxithromycin, furazolidone, enrofloxacin, norfloxacin, kanamycin, ampicillin, tetracycline, and vancomycin This is the first report of a phenomenon of golden pompano coinfection with S. agalactiae and S. iniae, which will contribute to the diagnosis and prevention of streptococcicosis.

Comparative studies on testicular and epididymal morphology, and serum hormone concentrations in foxes and the hybrids during the breeding season.

The silver fox and the blue fox belong to different genera, and the hybrid males are fully or partially sterile. In the present study, the objective was to evaluate the causes of hybrid male sterility, and therefore analyze the differences in testicular, and epididymal morphology and serum hormone concentrations among silver foxes, blue foxes, and the hybrids during the breeding season. Samples were collected from 20 male silver foxes, 20 male blue foxes, 15 male HSBs (silver fox female × blue fox male hybrids) and 14 male HBSs (blue fox male × silver fox female hybrids), respectively. Seminal evaluation showed large numbers of sperm present in the semen of blue foxes and silver foxes, but no sperm present in the hybrids. Mean testicular volume and the diameter of seminiferous tubules in silver foxes and blue foxes were greater than in the hybrids; and there were many Sertoli cells, spermatogenic cells, and sperm in silver foxes and blue foxes, while spermatogenic cells decreased with no sperm in the hybrids. Mean serum LH and prolactin concentrations in silver foxes and blue foxes were less and testosterone was greater than in the hybrids (P<0.05). The results indicate that germ cell meioses in the hybrids were arrested at the prophase stage of meiosis, and that lesser concentrations of testosterone and greater concentrations of LH and prolactin can inhibit the completion of spermatogenesis.

A study of autologous stem cells therapy assisted regeneration of cartilage in avascular bone necrosis.

Application of 'regenerative medicine' has given a new hope to surgeons for the treatment of several chronic diseases and disorders including severe orthopedic conditions. There are a myriad of orthopedic conditions and injuries that presently have limited therapeutic treatments and could benefit from new developing therapies in regenerative medicine with the help of stem cell therapy[1]. Regenerative medicine therapies are mainly based on the applications of stem cells. Stem cells play a vital role in orthopedic treatments and the studies have shown to have promising results in repair of bone, tendon, cartilage including avascular necrosis (AVN), spondylitis etc. Bone and cartilage regeneration ability of stem cells has been demonstrated clinically. However, success rate may not be same in every case and it depends on the patient profile. Several factors can be responsible for the same which include patient's immune response, the type and grade of the disease, which along with other confounding factors decide the outcome of the treatment. In this paper we have presented some of the orthopedic case studies performed through autologous transplantation of the stem cells.

Development and characterization of microsatellite loci in a threatened marine fish, Cheilinus undulatus (humphead wrasse).

Cheilinus undulatus (humphead wrasse) is a marine fish distributed widely throughout the tropical Indo-Pacific. It has been listed as vulnerable in the IUCN Red Data Book and in CITES Appendix II four times. Fifteen microsatellite loci were isolated and characterized for this species. The number of alleles ranged from 3 to 15 per locus, and the observed and expected heterozygosity ranged between 0.0323-0.7742 and 0.2597-0.8773, respectively. The polymorphism information content ranged from 0.2353-0.8520. Four microsatellite loci deviated significantly from Hardy-Weinberg expectations. No significant linkage disequilibrium was found among any of the loci. These microsatellite loci will be useful for future investigations of genetic variation in the wrasse population.

Isolation and characterization of 16 microsatellite loci in marble goby (Oxyeleotris marmoratus).

A microsatellite-enriched genomic library for marble goby (Oxyeleotris marmoratus), a freshwater fish of considerable economic value, was obtained. A total of 16 microsatellite markers were successfully isolated and characterized in a population from the Mekong River in Vietnam. These markers had 2-20 alleles with expected heterozygosity ranging from 0.0370 to 0.8927. Linkage equilibrium was observed in most loci, and only 1 locus revealed a significant deviation from Hardy-Weinberg equilibrium. These microsatellite markers will be useful for genetic diversity and molecular marker-assisted selection studies of wild and farmed O. marmoratus.

Electroluminescence enhancement of SiGe/Si multiple quantum wells through nanowall structures.

The enhancement of light extraction from Si(0.5)Ge(0.5)/Si multiple quantum wells (MQWs) with nanowall structures fabricated by electron cyclotron resonance (ECR) plasma etching is presented. It is shown that the ECR plasma treatment does not damage the crystalline quality. At a driving current of 5.5 × 10(6) A m(-2), the light output intensity of the MQWs with nanowall structures shows an enhancement of about 50% compared with that of the original MQWs. In addition to the enhanced light extraction, the improved optoelectronic properties are also attributed to the strain relaxation in nanowall structures.

Analysis of the entire genomes of thirteen TT virus variants classifiable into the fourth and fifth genetic groups, isolated from viremic infants.

TT virus (TTV) DNA in serum samples obtained from 24 TTV-infected infants was amplified by polymerase chain reaction (PCR) with inverse primers derived from the untranslated region. The amplified PCR products were molecularly cloned; six clones each were analyzed. Seventy-six (53%) of the 144 TTV clones were classified into group 4 (YONBAN isolates), and 22 (15%) into a novel genetic group (group 5). The TTV clones in group 4 were classified into 9 types, and those in group 5 into 4 types. The entire nucleotide sequence of one representative clone each from the 13 types were determined; they comprised 3570-3770 nucleotides, and had poor homology to TTVs of groups 1-3 (TA278, PMV and SANBAN isolates). A phylogenetic tree based on the entire nucleotide sequence of open reading frame 1 confirmed the presence of five distinct clusters separated by a bootstrap value of 100%. Analysis of 13 TTV variants demonstrated preservation of the genomic organization and transcription profile in all TTV groups. TTV group 4 was detected in 54% or 72% of 7-to-12-month-old infants in Japan and China, respectively, which is comparable with that among adults in the respective country, indicating early and frequent acquisition of this TTV group in infancy.

Essential role of Drosophila Hdac1 in homeotic gene silencing.

Deacetylation of the N-terminal tails of core histones plays a crucial role in gene silencing. Rpd3 and Hda1 represent two major types of genes encoding trichostatin A-sensitive histone deacetylases. Although they have been widely found, their cellular and developmental roles remain to be elucidated in metazoa. We show that Drosophila Hdac1, an Rpd3-type gene, interacts cooperatively with Polycomb group repressors in silencing the homeotic genes that are essential for axial patterning of body segments. The biochemical copurification and cytological colocalization of HDAC1 and Polycomb group repressors strongly suggest that HDAC1 is a component of the silencing complex for chromatin modification on specific regulatory regions of homeotic genes.

Response of pollen germination and tube growth to cadmium with special reference to low concentration exposure.

Cadmium is one of the most important heavy metal pollutants highly hazardous to plants. Pollen is considered to be more sensitive to pollutants than are vegetative parts of the plants. Five herb species were tested for responses in pollen germination and tube growth to Cd exposure in vitro. Pollen germination of all the species was inhibited at Cd concentrations of 2.51 microg/mL and higher, and tube growth was inhibited at concentrations of 1.58 microg/ml and higher. Cadmium, at low concentrations, stimulated pollen tube growth. The pollen response to Cd stress exhibited interspecies differences. Vicia angustifolia and V. tetrasperma were sensitive to Cd, and were inhibited in either pollen germination or tube growth by Cd at 0.01 microg/mL. Plantago depressa was less sensitive; pollen germination and tube growth were not inhibited until the Cd concentration reached 2.51 and 1.58 microg/mL, respectively, and its tube growth displayed two stimulatory peaks; the one that appeared at 1.00 microg/mL showed the highest tube length in all species tested. These results suggest that Cd, even at low concentrations, may adversely affect plant reproduction by inhibiting pollen germination and tube growth.