Investigation of killer cell immunoglobulin-like receptors KIR2DL2 and KIR2DL3 diversity and identification of ten novel KIR2DL3 alleles in the Chinese Han population

KIR2DL2 and KIR2DL3 are important inhibitory receptors that recognize a subset of HLA-C allelic products carrying Ser77 and Asn80. In this study, we have determined KIR2DL2 and KIR2DL3 diversity in the Chinese Han population by a PCR sequence-based typing. Based on sequencing, the coding regions of 166 Chinese Han individuals, seven new polymorphic sites (238G>A, 405G>A, 476A>G, 550G>A, 608G>A, 789T>C, 947T>C) were found. KIR2DL2*00301, *00101, KIR2DL3*00101,*00201,*013, *015 and ten new KIR2DL3 variants (KIR2DL3*00105, 00106, 00107, 00108, 019, 020, 021, 022, 023 and 024) were identified, of which KIR2DL3*00101 was the most frequent allele. Compared with the sequences of KIR2DL3*00101, all sequences of 2DL3*00105, 2DL3*00106, 2DL3*00107 and 2DL3*00108 had one nucleotide substitution(789T>C, 261C>T, 489G>A and 405G>A),but none resulted in amino acid change. An A>G substitution was observed in nucleotide position 476 in 2DL3*019, 608 G>A in 2DL3*020, 824T>C in 2DL3*021 and 238 G>A in 2DL3*023. In addition, 2DL3*022 probably arose from 2DL3*00201 with a nucleotide substitution G>A at 550. There were more HLA-C1 positive individuals than HLA-C2. In conclusion, the data of allelic polymorphism for KIR2DL2 and KIR2DL3 were obtained in the Chinese Han population and ten novel KIR2DL3 alleles were identified.

Mixed-matrix membranes containing functionalized porous metal–organic polyhedrons for the effective separation of CO2–CH4 mixture

The gas permeability and separation factor for CO₂–CH₄ separation were improved simultaneously in mixed-matrix membranes formed by metal–organic polyhedrons and polysulfone.

Recovery of acetone from aqueous solution by ZIF-7/PDMS mixed matrix membranes

Mixed matrix membrane containing ZIF-7 exhibits the excellent performance in the recovery of acetone from fermentation broths.

Highly selective adsorption and separation of aniline/phenol from aqueous solutions by microporous MIL-53(Al): a combined experimental and computational study

Experimental measurements have been combined with molecular simulations to investigate the adsorption and separation of aniline/phenol mixtures from aqueous solutions by the aluminum terephthalate MIL-53. The results show that the framework flexibility of this material plays a crucial role in the adsorption process and thus can greatly enhance the separation of the aniline/phenol mixture from their solutions. Compared with the conventional adsorbents, MIL-53(Al) shows the best performance for such systems of interest, from the points of view of both the adsorption capacities and the selectivities for aniline. The findings obtained in this work may facilitate more investigations in connection with the application of flexible nanoporous materials for the separation of organic compounds from liquid-phase environments.

The effects of feeding time on milk production, total-tract digestibility, and daily rhythms of feeding behavior and plasma metabolites and hormones in dairy cows

The timing of feed intake entrains circadian rhythms regulated by internal clocks in many mammals. The objective of this study was to determine if the timing of feeding entrains daily rhythms in dairy cows. Nine Holstein cows were used in a replicated 3 × 3 Latin square design with 14-d periods. An automated system recorded the timing of feed intake over the last 7 d of each period. Treatments were feeding 1×/d at 0830 h (AM) or 2030 h (PM) and feeding 2×/d in equal amounts at 0830 and 2030 h. All treatments were fed at 110% of daily intake. Cows were milked 2×/d at 0500 and 1700 h. Milk yield and composition were not changed by treatment. Daily intake did not differ, but twice-daily feeding tended to decrease total-tract digestibility of organic matter and neutral detergent fiber (NDF). A treatment by time of day interaction was observed for feeding behavior. The amount of feed consumed in the first 2h after feeding was 70% greater for PM compared with AM feeding. A low rate of intake overnight (2400 to 0500 h; 2.2 ± 0.74% daily intake/h, mean ± SD) and a moderate rate of intake in the afternoon (1200 to 1700 h; 4.8 ± 1.1% daily intake/h) was noted for all treatments, although PM slightly reduced the rate during the afternoon period compared with AM. A treatment by time of day interaction was seen for fecal NDF and indigestible NDF (iNDF) concentration, blood urea nitrogen, plasma glucose and insulin concentrations, body temperature, and lying behavior. Specifically, insulin increased and glucose decreased more after evening feeding than after morning feeding. A cosine function within a 24-h period was used to characterize daily rhythms using a random regression. Rate of feed intake during spontaneous feeding, fecal NDF and iNDF concentration, plasma glucose, insulin, NEFA, body temperature, and lying behavior fit a cosine function within a 24-h period that was modified by treatment. In conclusion, feeding time can reset the daily rhythms of feeding and lying behavior, core body temperature, fecal NDF and iNDF concentration, and plasma blood urea nitrogen, glucose, and insulin concentration of dairy cows, but has no effect on daily DMI and milk production.

Detection and survival of Toxoplasma gondii in milk and cheese from experimentally infected goats

The consumption of unpasteurized goat cheese and goat's milk has been suggested as a risk factor for toxoplasmosis in humans. In the present study, detection and survival of Toxoplasma gondii in milk and cheese was studied by bioassay in mice (milk) and in cats (cheese). Eight goats were inoculated orally with 300 to 10,000 oocysts of T. gondii strain TgGoatUS26. Milk samples were collected daily up to 30 days postinoculation and bioassayed in mice and cats. For mouse bioassay, 50 ml of milk samples were centrifuged, and the sediment was inoculated subcutaneously into mice. Mice were tested for T. gondii infection by seroconversion and by the demonstration of parasites. By mouse bioassay, T. gondii was detected in milk from all eight goats. The T. gondii excretion in milk was intermittent. For cat bioassay, 400 ml (100 ml or more from each goat) of milk from four goats from 6 to 27 days postinoculation were pooled daily, and cheese was made using rennin. Ten grams of cheese was fed daily to four cats, and cat feces were examined for oocyst shedding. One cat fed cheese shed oocysts 7 to 11 days after consuming cheese. Attempts were made to detect T. gondii DNA in milk of four goats; T. gondii was detected by PCR more consistently, but there was no correlation between detection of viable T. gondii by bioassay in mice and T. gondii DNA by PCR. Results indicate that T. gondii can be excreted in goat's milk and can survive in fresh cheese made by cold-enzyme treatment. To prevent transmission to humans or animals, milk should not be consumed raw. Raw fresh goat cheese made by cold-enzyme treatment of unpasteurized milk also should not be consumed.

Surveillance of feral swine for Trichinella spp. and Toxoplasma gondii in the USA and host-related factors associated with infection

Trichinella spp. and Toxoplasma gondii are important zoonotic parasites that infect warm blooded animals and humans worldwide. Among domesticated food animals, pigs are the main host for Trichinella spiralis. Pigs, chickens, sheep, and goats are known to be infected with T. gondii at varying rates, depending on husbandry. Infections in wildlife with these parasites are generally higher than in domesticated species. Feral swine act as reservoirs of infection in the sylvatic ecosystem for Trichinella spp. and T. gondii, acting as sources of infection for peridomestic carnivores whose home ranges overlap with domestic pigs. Feral swine can have direct contact with non-biosecure domestic pigs, presenting opportunity for direct disease transmission through cannibalistic behavior. Determination of the prevalence of Trichinella spp. and T. gondii infection in feral swine is needed to understand the risk of transmission of these parasites to domestic pigs. A cross-sectional serological survey was conducted between 2006 and 2010 to estimate the antibody prevalence of Trichinella spp. and T. gondii and risk factors associated with infection in feral swine in the USA. Serum samples were tested from 3247 feral pigs from 32 states; results are reported from 26 states. Maximum entropy ecological niche modeling and spatial scan statistic were utilized to predict the geographic range and to examine clusters of infection of Trichinella spp. and T. gondii in feral pigs. The seroprevalence of antibodies to Trichinella spp. and T. gondii was 3.0% and 17.7%, respectively. Species distribution modeling indicated that the most probable distribution areas for both parasites was similar, concentrated primarily in the South and the Midwest regions of the USA. A follow up survey conducted during 2012-2013 revealed that 2.9% of 984 sampled feral swine were seropositive for Trichinella spp., and 28.4% were seropositive for T. gondii. Three hundred and thirty (330) tongues were collected from the 984 sampled animals during 2012-2013; 1.81% were tissue positive for T. spiralis muscle larvae; no other genotypes were found. The potential exists for introduction of these pathogens into domestic herds of non-biosecure domestic pigs as a result of increasing overlap of the range of feral pigs with non-biosecure domestic pigs production facilities in the USA.

Comparison of enriched palmitic acid and calcium salts of palm fatty acids distillate fat supplements on milk production and metabolic profiles of high-producing dairy cows

A variable response to fat supplementation has been reported in dairy cows, which may be due to cow production level, environmental conditions, or diet characteristics. In the present experiment, the effect of a high palmitic acid supplement was investigated relative to a conventional Ca salts of palm fatty acids (Ca-FA) supplement in 16 high-producing Holstein cows (46.6±12.4kg of milk/d) arranged in a crossover design with 14-d periods. The experiment was conducted in a non-heat-stress season with 29.5% neutral detergent fiber diets. Treatments were (1) high palmitic acid (PA) supplement fed as free FA [1.9% of dry matter (DM); 84.8% C16:0] and (2) Ca-FA supplement (2.3% of DM; 47.7% C16:0, 35.9% C18:1, and 8.4% C18:2). The PA supplement tended to increase DM intake, and increased the yields of milk and energy-corrected milk. Additionally, PA increased the yields of milk fat, protein, and lactose, whereas milk concentrations of these components were not affected. The yields of milk de novo and 16-C FA were increased by PA compared with Ca-FA (7 and 20%, respectively), whereas the yield of preformed FA was higher in Ca-FA. A reduction in milk fat concentration of de novo and 16-C FA and a marginal elevation in trans-10 C18:1 in Ca-FA is indicative of altered ruminal biohydrogenation and increased risk of milk fat depression. No effect of treatment on plasma insulin was observed. A treatment by time interaction was detected for plasma nonesterified fatty acids (NEFA), which tended to be higher in Ca-FA than in PA before feeding. Overall, the palmitic acid supplement improved production performance in high-producing cows while posing a lower risk for milk fat depression compared with a supplement higher in unsaturated FA.

Effect of a high-palmitic acid fat supplement on milk production and apparent total-tract digestibility in high- and low-milk yield dairy cows

The effect of a high-palmitic acid fat supplement was tested in 12 high-producing (mean = 42.1 kg/d) and 12 low-producing (mean = 28.9 kg/d) cows arranged in a replicated 3 × 3 Latin square design. Experimental periods were 21 d, with 18d of diet adaptation and 3 d of sample collection. Treatments were (1) control (no supplemental fat), (2) high-palmitic acid (PA) supplement (84% C16:0), and (3) Ca salts of palm fatty acid (FA) supplement (Ca-FA). The PA supplement had no effect on milk production, but decreased dry matter intake by 7 and 9% relative to the control in high- and low-producing cows, respectively, and increased feed efficiency by 8.5% in high-producing cows compared with the control. Milk fat concentration and yield were not affected by PA relative to the control in high- or low-producing cows, although PA increased the yield of milk 16-C FA by more than 85 g/d relative to the control. The Ca-FA decreased milk fat concentration compared with PA in high-, but not in low-producing cows. In agreement, Ca-FA dramatically increased milk fat concentration of trans-10 C18:1 and trans-10, cis-12 conjugated linoleic acid (>300%) compared with PA in high-producing cows, but not in low-producing cows. No effect of treatment on milk protein concentration or yield was detected. The PA supplement also increased 16-C FA apparent digestibility by over 10% and increased total FA digestibility compared with the control in high- and low-producing cows. During short-term feeding, palmitic acid supplementation did not increase milk or milk fat yield; however, it was efficiently absorbed, increased feed efficiency, and increased milk 16-C FA yield, while minimizing alterations in ruminal biohydrogenation commonly observed for other unsaturated fat supplements. Longer-term experiments will be necessary to determine the effects on energy balance and changes in body reserves.

Analysis of rumen microbial populations in lactating dairy cattle fed diets varying in carbohydrate profiles and Saccharomyces cerevisiae fermentation product

The rumen microbial ecosystem is a critical factor that links diets to bovine physiology and productivity; however, information about dietary effects on microbial populations has generally been limited to small numbers of samples and qualitative assessment. To assess whether consistent shifts in microbial populations occur in response to common dietary manipulations in dairy cattle, samples of rumen contents were collected from 2 studies for analysis by quantitative real-time PCR (qPCR). In one study, lactating Holstein cows (n=8) were fed diets in which a nonforage fiber source replaced an increasing proportion of forages and concentrates in a 4×4 Latin square design, and samples of ruminal digesta were collected at 9-h intervals over 3 d at the end of each period. In the second study, lactating Holstein cows (n=15) were fed diets with or without the inclusion of a Saccharomyces cerevisiae fermentation product (SCFP) in a crossover design. In this study, rumen liquid and solid samples were collected during total rumen evacuations before and after feeding in a 42-h period. In total, 146 samples of ruminal digesta were used for microbial DNA isolation and analysis by qPCR. Validated primer sets were used to quantify total bacterial and anaerobic fungal populations as well as 12 well-studied bacterial taxa. The relative abundance of the target populations was similar to those previously reported. No significant treatment effects were observed for any target population. A significant interaction of treatment and dry matter intake was observed, however, for the abundance of Eubacterium ruminantium. Increasing dry matter intake was associated with a quadratic decrease in E. ruminantium populations in control animals but with a quadratic increase in E.ruminantium populations in cows fed SCFP. Analysis of sample time effects revealed that Fibrobacter succinogenes and fungal populations were more abundant postfeeding, whereas Ruminococcus albus tended to be more abundant prefeeding. Seven of the target taxa were more abundant in either the liquid or solid fractions of ruminal digesta. By accounting for the total mass of liquid and solid fractions in the rumen and the relative abundance of total bacteria in each fraction, it was estimated that 92% of total bacteria were found in the solid digesta fraction.

Prevalence of the HPA-18w to -21w alleles in the Chinese Han population

Recently, four new platelet alloantigen (HPA) systems HPA-18w to-21w were identified. However, genotyping for HPA-18w to -21w alleles was rarely reported. Here, we established a polymerase chain reaction sequence-based typing (PCR-SBT) method and investigated the distribution of HPA-18w to -21w alleles in the Chinese Han population. The specific primers of HPA-18w, -19w, -20w and -21w were designed, and the PCR products were bidirectionally sequenced. 855 randomly selected platelet donors were genotyped for HPA-18w to -21w with the PCR-SBT method. The results showed that all individuals were monomorphic for HPA-18w to HPA-20w with a/a homozygous frequency of 1.0 and absence of HPA-18bw to -20bw alleles. The frequencies of the HPA-21a/21a and HPA-21a/21b genotypes were 0.981(839/855) and 0.019(16/855), respectively. Seven mutations were confirmed on sequenced region separate from HPA polymorphisms, including ITGA2 (IVS17+48G>A and IVS17+72G>A), ITGA2B (IVS19-26C>G) and ITGB3 (IVS4+234C>T, IVS11-19 T>C, IVS11-104T>C and GT repeats from IVS11-131 to IVS11-109). These data will provide useful information for diagnosis, prevention and treatment of alloimmune thrombocytopaenia.

C35T mutation could slightly decrease the activity of human α-(1,2)-fucosyltransferase

PURPOSE OF THE STUDY

The C35T mutant α-(1,2)-fucosyltransferase (FUT1) gene had been reported related to the para-Bombay phenotype, but recently, our laboratory found that the C35T was a polymorphism in the Chinese population. This study aims at further clarifying the property of C35T mutant FUT1.

MATERIAL AND METHODS

The mutant C35T FUT1 gene was cloned into expression vector in vitro, the mRNA expression was analyzed by real-time quantitative polymerase chain reaction (PCR), and the mutant enzyme's activity was determined in vitro.

RESULTS

The results showed that the frequencies of 35C and 35T alleles were 0.735 and 0.265, respectively. The FUT1 mRNA level of transfected cells with C35T recombination vector showed 99.85% of the wild-type FUT1 transfected cells. The enzyme relative activity of transfected cell lysates with C35T FUT1 recombination vector was 79.45% compared with that of the wild-type FUT1 transfected cell lysates. The K(m)(phenyl-gal) value of enzyme encoded by C35T allele was 0.5 times higher than that of the enzyme encoded by FUT1 wild-type allele.

CONCLUSION

These results suggested that FUT1 C35T was a polymorphism in the Chinese population and did not affect its mRNA transcription, but could slightly decrease the activity of human α-(1,2)-fucosyltransferase in vitro.

A novel FUT1 allele was identified in a Chinese individual with para-Bombay phenotype

BACKGROUND

The para-Bombay phenotype is characterised by H-deficient or H partially deficient red blood cells (RBCs) in individuals who secrete ABH antigens in their saliva. Samples from an individual whose RBCs had an apparent para-Bombay phenotype and his family members were investigated and a novel FUT1 allele was identified.

MATERIALS AND METHODS

RBCs' phenotype was characterised by standard serologic technique. Genomic DNA was sequenced with primers that amplified the coding sequence of FUT1 and FUT2, respectively. Routine ABO genotyping analysis was performed. Haplotypes of FUT1 were identified by TOPO cloning sequencing. Recombination expression vectors of FUT1 mutation alleles were constructed and transfected into COS-7 cells. The pα-(1,2)-fucosyltransferase activity of expression protein was determined.

RESULTS

B101/O02 genotype of the proband was correlated with ABH substances in saliva. The proband carried a new FUT1 allele which showed 35C/T, 235G/C and 682A/G heterozygote by directly DNA sequencing. Two haplotypes, 235C and 35T+682G, were identified by TOPO cloning sequencing and COS-7 cells transfected with five recombination vectors including wild-type, 35T, 235C, 682G and 35T+682G alleles were established respectively. The α-(1,2)-fucosyltransferase activities of cell lysates which had transfected with 35T, 235C, 682G and 35T+682G recombination vectors showed 79·45, 16·23, 80·32 and 24·59%, respectively, compared with that of the wild-type FUT1-transfected cell lysates.

CONCLUSION

A novel FUT1 allele 235C was identified, which greatly diminished the activity of α-(1,2)-fucosyltransferase.

Human platelet antigen allele frequencies and new mutations on platelet glycoprotein genes in the Chinese Han population

BACKGROUND AND OBJECTIVES

The frequencies of human platelet antigens (HPAs) vary between different populations. In this study, we determined the HPA allele frequencies in the Chinese Han population and identified situation of incompatibility possibly leading to alloimmunisation.

METHODS

A total of 750 volunteer blood donors of the Chinese Han population were genotyped for HPA-1 to -17w systems. HPA genotyping was determined by polymerase chain reaction sequence-based typing.

RESULTS

Among the 17 HPA systems, the allele frequency is different from other populations. We noted the absence of HPA-7bw to HPA-14bw, HPA-16bw and HPA-17bw alleles in the population. The estimated incompatibility probabilities regarding platelet antigens 1 to 6w and 15 systems after transfusion of random donor platelet were from 0·004 to 0·373. Thirteen glycoprotein alleles were observed in the population. In addition, we identified 16 novel mutations on the glycoprotein genes separated from HPA polymorphisms, including GP1BA (517-525delAAC), ITGA2B (2722C>T and IVS26+85T>C), ITGA2 (1521C>T, 2474T>G and IVS20+10 G>C), ITGB3 (1476G>A, IVS10+19C>A, 1813G>A, IVS11+21G>A, IVS11+152A>G and IVS11-104T>C), GP1BB (IVS1-79G>A, IVS1-27C>T and 129G>A) and CD109 (2139A>G). Five of them could lead to amino acid deletion, substitution or premature stop codon in corresponding glycoprotein.

CONCLUSIONS

There was a high degree of polymorphism of the membrane glycoprotein genes related to human platelet alloantigen-1 to -17w systems in the Chinese Han population. These data could have some impact on the diagnosis, prevention and treatment of alloimmune thrombocytopenia.

Distribution of ABO blood group allele and identification of three novel alleles in the Chinese Han population

BACKGROUND

The ABO blood group system is clinically important in blood transfusion. The molecular characterization of ABO blood group has clinical and anthropological importance. Here, we determined the ABO alleles distribution and identified three novel alleles in the Chinese Han population.

STUDY DESIGN AND METHODS

Four hundred and seventeen Chinese Han individuals were determined by standard serologic techniques for the ABO blood group phenotypes. The ABO genotypes and alleles were analysed by polymerase chain reaction sequence-based typing (PCR-SBT) for sequencing exon 6 to 7 of the ABO gene. The polymorphisms of intron 5 and 6 of the ABO gene were also analysed by PCR-SBT. The two haplotypes including new alleles were separated by a Dynabeads M-270 Streptavidin protocol.

RESULTS

All ABO genotypes of the samples were consistent with the phenotypes. Fourteen alleles were identified based on the nucleotide sequences of exon 6 and 7, with five common alleles (A101, A102, B101, O01 and O02), six known rare alleles (A205, B110, O04, O05, O07 and O50) and three novel alleles (B112, CisAB06 and 061). The three new alleles appeared with the frequencies of 0.12%, 0.12% and 0.36%, respectively.

CONCLUSION

The detailed frequencies distribution of ABO alleles was studied in the Chinese Han population. We identified 14 alleles, including 3 novel alleles.

49. Effect of a resident-as-teacher training programme on surgical resident clinical teaching skills

This study was designed to assess the benefits of a resident-as-teacher training programme on surgical residents within a surgical clinical teaching unit. A randomized controlled trial was conducted at McMaster University between July 2005 and June 2006. Twenty-eight (28) General Surgery Residents and one 134 Medical Students participated in the study. Residents were randomly assigned to participate in a two-day training course on clinical teaching skills at the 3 or 12-month interval. Medical Students completed teaching evaluations on residents whom they had significant exposure. Resident scores on teaching evaluations as well as medical student performance on rotation examinations were assessed. The intervention (n=14) and control (n=14) groups were at similar levels of training. Only 5 intervention and 9 control residents had both pre and post intervention evaluations. Evaluations were measured on a 1 to 5 Likert scale. Data was analyzed by intention-to-treat. The mean evaluation score in both control and intervention groups were higher than pre-intervention (8% and 14%, p=0.03). However, the magnitude of change between the 2 groups was not statistically significant. Medical student performance by those exposed to more intervention residents was not significantly different from those exposed to more control residents. There is a significant improvement in resident teaching over an academic year, as determined by medical student evaluations of the resident-teachers. Although there was a trend of improved teaching with the teaching- skills intervention, the difference was not statistically significant, and did not affect medical student performance on the end-of rotation examinations. Blue AV, et al. Surgical Teaching Quality Makes a Difference. American Journal of Surgery 1999; 177:86-9. Dunnington GL, DaRosa D. A prospective Randomized Trial of Residents-as-teachers Training Program. Academic Medicine 1998; 73: 696-700. Griffith CH, et al. Relationship of How Well Attending Physicians Teach to Their Students’ Performances and Residency Choices. Academic Medicine 1997; 72:S118-120.

Sustained and stable hematopoietic donor-recipient mixed chimerism after unrelated cord blood transplantation for adult patients with severe aplastic anemia

We evaluated the engraftment of donor cells from unrelated cord blood into adult patients with severe aplastic anemia (SAA) and the outcome of allo-CBSCT (cord blood stem cell transplantation). Nine patients were conditioned with decreased dosage of immunosuppressive agents of CTX (60 mg/kg) and ALG (120 mg/kg). The prophylaxis of GVHD consisted of standard CsA and MTX. Patients have a media age of 25.3 yr (range: 15-37), and a median weight of 57.2 kg (range: 52.5-60) at the time of transplantation. Cord blood searches were all conducted at Guangzhou Cord Blood Bank. The engraftment state of the donor cells into recipients was confirmed by microsatellite DNA fingerprinting and fluorescent quantitative PCR analysis. Engrafted evidence has been found in seven patients involved by biomolecular analyses showing donor-recipient mixed chimerism post-transplant which was stable and persistent. After a median follow up of 32.2 months (range: 4-69), seven patients were alive and disease free. This study shows that durable donor-recipient stable mixed chimerism can be achieved by unrelated CBSCT in patients with SAA. Umbilical cord blood could be employed as a source of hematopoietic stem cell for adult transplantation.

Umbilical cord blood transplant for adult patients with severe aplastic anemia using anti-lymphocyte globulin and cyclophosphamide as conditioning therapy

Allo-CBSCT (cord blood stem cell transplant) has been applied in six adult patients with severe aplastic anemia (SAA). Anti-lymphocyte globulin (ALG) 40 mg kg(-1) d(-1) x 3 days combined with cyclophosphamide (CTX) 20 mg kg(-1) d(-1) x 3 days constituted a lower intensive conditioning regimen. The prophylaxis of GVHD consisted of standard CsA and MTX. Patients are all male having a mean age of 26.5 years (range 22-38), and a median weight of 55.6 kg (range 52-60 kg). Cord blood searches were all conducted at Guangzhou Cord Blood Bank. Three of six patients in our study received one unit of cord blood in a procedure, whereas for another three patients, two units of cord blood (double units) were infused at the same time in a transplant protocol. The nine units of umbilical cord blood (UCB) infused contained 1.6-10.7 x 10(7) nucleated cells/kg body weight of the recipient after thawing. HLA antigens were identical in one unit, 1 antigen mismatched in seven, 2 antigens mismatched in 1. As of February 2003, after a median follow up of 20 months (range 7-50), four patients are alive and disease free. Five patients engrafted with molecular biology analyses showing donor-recipient mixed chimerism post transplant which is stable and persistent. One patient died of severe infection in the third month from transplant and another patient died in the early stage post transplant of serious aspergillus infection without evidence of engraftment.

Induction of primordial germ cells from murine epiblasts by synergistic action of BMP4 and BMP8B signaling pathways

Extraembryonic ectoderm-derived factors instruct the pluripotent epiblast cells to develop toward a restricted primordial germ cell (PGC) fate during murine gastrulation. Genes encoding Bmp4 of the Dpp class and Bmp8b of the 60A class are expressed in the extraembryonic ectoderm and targeted mutation of either results in severe defects in PGC formation. It has been shown that heterodimers of DPP and 60A classes of bone morphogenetic proteins (BMPs) are more potent than each homodimers in bone and mesoderm induction in vitro, suggesting that BMP4 and BMP8B may form heterodimers to induce PGCs. To investigate how BMP4 and BMP8B interact and signal for PGC induction, we cocultured epiblasts of embryonic day 6.0--6.25 embryos with BMP4 and BMP8B proteins produced by COS cells. Our data show that BMP4 or BMP8B homodimers alone cannot induce PGCs whereas they can in combination, providing evidence that two BMP pathways are simultaneously required for the generation of a given cell type in mammals and also providing a prototype method for PGC induction in vitro. Furthermore, the PGC defects of Bmp8b mutants can be rescued by BMP8B homodimers whereas BMP4 homodimers cannot mitigate the PGC defects of Bmp4 null mutants, suggesting that BMP4 proteins are also required for epiblast cells to gain germ-line competency before the synergistic action of BMP4 and BMP8B.

Thermolysis of free-radical initiators: tert-butylazocumene and its 1,3- and 1,4-bisazo and 1,3,5-trisazo analogues

Four tert-butylazocumenes (4-7) were prepared from the corresponding cyanobenzenes, and their nitrogen evolution kinetics and products were analyzed. In combination with TEMPO, the simplest compound, tert-butylazocumene (4), shows promise as a "one-radical" initiator of styrene polymerization. The ABNO-trapped cumyl radical 29 is a particularly stable trialkylhydroxylamine, whose thermolysis half-life is 2.1 h at 150 degrees C. Taking advantage of this stability, we trapped the cumyl radical centers from 7 to afford tris adduct 32a. While the behavior of the meta bisazoalkane 6 can be mostly predicted from that of 4, the para isomer 5 exhibits both unusual products and kinetics, attributed to the formation of quinodimethane 33 via azo-containing radical 34. In fact, flash vacuum pyrolysis of 5 allowed observation of the (1)H and (13)C NMR spectra of 33, whose persistence even at ambient temperature showed that this quinodimethane is far more stable than the parent 36. Finally, evidence is presented that 7 is an initiator of star polymerization.

Cooperation of endoderm-derived BMP2 and extraembryonic ectoderm-derived BMP4 in primordial germ cell generation in the mouse

The primordial germ cells (PGCs) of the mouse are derived from proximal epiblast cells that are adjacent to the extraembryonic ectoderm during gastrulation. Previous studies have demonstrated that extraembryonic ectoderm-derived BMP4 and BMP8B are both required for PGC generation. Here we show that Bmp2, a member of the Dpp class of the Bmp superfamily, also plays a role in PGC generation. PGC number is significantly reduced in Bmp2 heterozygous and homozygous embryos at the N2 generation onto C57BL/6 background. Bmp2 homozygous embryos also have a short allantois and about 50% of them do not undergo normal chorioallantoic fusion. Using whole-mount in situ hybridization, we show that Bmp2 is primarily expressed in the endoderm of mouse pregastrula and gastrula embryos. Using a genetic approach, we further show that Bmp2 and Bmp4, but not Bmp2 and Bmp8b, have an additive effect on PGC generation. These results suggest that PGC generation in the mouse embryo is regulated not only by extraembryonic ectoderm-derived BMP4 and BMP8B, but also by endoderm-derived BMP2.