Genetic polymorphisms of p53 and GSTP1,but not NAT2,are associated with susceptibility to squamous-cell carcinoma of the esophagus

The interaction of genetic and environmental factors can determine an individual's susceptibility to various cancers. We present a hospital-based case-control study, which included 90 patients of esophageal squamous-cell carcinoma (ESCC) and 254 healthy people in Taiwan, to investigate the effects of genetic polymorphisms of p53, GSTP1 and NAT2 on the risk of ESCC. Polymorphisms of p53, NAT2 and GSTP1 were determined by PCR-RFLP. The codon 72 p53 Pro allele was more frequently found in ESCC patients [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.04-3.35 for Arg/Pro genotype and OR 2.56, 95% CI 1.29-5.08 for Pro/Pro genotype]. In cigarette smokers, the frequency of GSTP1 Ile/Ile genotype was higher in ESCC patients (OR 2.8, 95% CI 1.4-5.7). Among alcohol drinkers, borderline significance was also found for GSTP1 Ile/Ile genotype (OR 2.0, 95% CI 0.9-4.4). Results were not similar for the NAT2 genetic polymorphism. Using logistic analyses, we found that individuals with p53 Pro/Pro genotype had a significantly higher risk of developing ESCC than those with Arg/Arg genotype (OR 2.3, 95% CI 1. 1-5.1), after adjusting for other significant environmental risk factors. This result remained similar (OR 2.2, 95% CI 1.0-4.8 for p53 Pro/Pro vs. Arg/Arg), even after further adjustment for NAT2 and GSTP1 polymorphisms. The codon 72 p53 Pro/Pro genotype in the general population and GSTP1 Ile/Ile in cigarette smokers may predict a higher risk of developing ESCC.

Genetic polymorphisms of p53 and GSTP1,but not NAT2,are associated with susceptibility to squamous-cell carcinoma of the esophagus

The interaction of genetic and environmental factors can determine an individual's susceptibility to various cancers. We present a hospital-based case-control study, which included 90 patients of esophageal squamous-cell carcinoma (ESCC) and 254 healthy people in Taiwan, to investigate the effects of genetic polymorphisms of p53, GSTP1 and NAT2 on the risk of ESCC. Polymorphisms of p53, NAT2 and GSTP1 were determined by PCR-RFLP. The codon 72 p53 Pro allele was more frequently found in ESCC patients [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.04-3.35 for Arg/Pro genotype and OR 2.56, 95% CI 1.29-5.08 for Pro/Pro genotype]. In cigarette smokers, the frequency of GSTP1 Ile/Ile genotype was higher in ESCC patients (OR 2.8, 95% CI 1.4-5.7). Among alcohol drinkers, borderline significance was also found for GSTP1 Ile/Ile genotype (OR 2.0, 95% CI 0.9-4.4). Results were not similar for the NAT2 genetic polymorphism. Using logistic analyses, we found that individuals with p53 Pro/Pro genotype had a significantly higher risk of developing ESCC than those with Arg/Arg genotype (OR 2.3, 95% CI 1. 1-5.1), after adjusting for other significant environmental risk factors. This result remained similar (OR 2.2, 95% CI 1.0-4.8 for p53 Pro/Pro vs. Arg/Arg), even after further adjustment for NAT2 and GSTP1 polymorphisms. The codon 72 p53 Pro/Pro genotype in the general population and GSTP1 Ile/Ile in cigarette smokers may predict a higher risk of developing ESCC.

Detection of beta-amyloid peptide aggregation using DNA electrophoresis

DNA could readily associate with the aggregated forms of the beta-amyloid peptides beta(1-40) and beta(25-35), giving rise to a shift in the electrophoretic mobility of DNA. As a result, DNA was retained at the top of a 1% agarose gel. In contrast, the electrophoretic mobility of DNA was little influenced by the monomeric forms of beta(1-40) and beta(25-30). DNA from different sources such as lambda phage, Escherichia coli plasmid, and human gene showed similar results. However, the electrophoretic mobility of RNA was shifted by the monomeric beta(1-40) and beta(25-35) as well as by the aggregated beta(1-40) and beta(25-35). The association of DNA with the aggregated beta-amyloid peptides could occur at pH 4-9. The inhibitory action of hemin on beta-amyloid aggregation could be confirmed using the DNA mobility shift assay. These results indicate that the DNA mobility shift assay is useful for kinetic study of beta-amyloid aggregation as well as for testing of agents that might modulate beta-amyloid aggregation.

Identification of Ankrd2, a novel skeletal muscle gene coding for a stretch-responsive ankyrin-repeat protein

Mechanically induced hypertrophy of skeletal muscles involves shifts in gene expression leading to increases in the synthesis of specific proteins. Full characterization of the regulation of muscle hypertrophy is a prerequisite for the development of novel therapies aimed at treating muscle wasting (atrophy) in human aging and disease. Using suppression subtractive hybridization, cDNAs corresponding to mRNAs that increase in relative abundance in response to mechanical stretch of mouse skeletal muscles in vivo were identified. A novel 1100-bp transcript was detected exclusively in skeletal muscle. This exhibited a fourfold increase in expression after 7 days of stretch. The transcript had an open reading frame of 328 amino acids encoding an ATP/GTP binding domain, a nuclear localization signal, two PEST protein-destabilization motifs, and a 132-amino-acid ankyrin-repeat region. We have named this gene ankyrin-repeat domain 2 (stretch-responsive muscle) (Ankrd2). We hypothesize that Ankrd2 plays an important role in skeletal muscle hypertrophy.

The oldest known tracks of web-footed birds from the lower Cretaceous of South Korea

We describe the oldest tracks of web-footed birds from the Early Cretaceous in South Korea. The tracks are characterized by a wide divarication angle and a long reversed hallux. The web is semipalmate and restricted to the proximal portion of the three forward digits. The tracks from the Early Cretaceous in South Korea are smaller than those of the Late Cretaceous, therefore confirming the trend of size increasing in the early evolution of birds as shown by skeletal fossils. The discovery of web-footed tracks with abundant non-web-footed tracks indicates that there was a considerable diversification of shore birds as early as the Early Cretaceous.

HLA class II alleles associated with susceptibility and resistance to Crohn's disease in the Jewish population

Previous studies have suggested that susceptibility to Crohn's disease (CD) is associated with the histocompatibility complex (HLA) class II alleles DR1, DQ5, and DR13 in the Caucasian population, DR7 in the French and German populations, and DR4 and DQ4 in the Japanese population. However, little is known about the relationship between HLA class II alleles and CD in the Jewish population since these previous studies included few Jewish individuals. In order to determine whether the HLA associations observed with predominantly non-Jewish populations were also present in the Jewish CD population and whether there were any HLA class II alleles uniquely associated with CD in the Jewish population, 132 CD patients, of which 82 were Ashkenazi Jewish, were HLA-typed using serologic and DNA methods. Ethnically matched controls were similarly typed. No association with DR1 or DR13 was observed in the Jewish CD population although an association with DR13 (OR [odds ratio] = 5.3, p = 0.02) was observed in the non-Jewish CD population. However, an association with DR15 (OR = 2.7, p = 0.03), which is normally associated with ulcerative colitis, was observed in the Jewish, but not non-Jewish, CD group. In addition, a strong negative association was observed with DR3, which was especially striking in the Jewish population (OR = 0.35, p = 0.025); similar negative associations with DR3 have been observed by others using non-Jewish populations. Furthermore, a significant negative association with DR7 (OR = 0.45, p = 0.04) was observed in the Jewish, but not non-Jewish, population. Consistent with this was the negative association with DQ2 (OR = 0.38, p = 0.005), which is in strong linkage disequilibrium with both DR3 and DR7, in the Jewish, but not non-Jewish, population. These studies support previous suggestions that susceptibility to CD in Jewish and non-Jewish populations is determined by distinct genes and provide further support to the hypothesis that a gene on the DR3 haplotype may protect against CD. Furthermore, protection is conferred by the same or another gene found on Jewish, but not non-Jewish, DR7 haplotypes.

Function of human brain short chain L-3-hydroxyacyl coenzyme A dehydrogenase in androgen metabolism

Human brain short chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) has been demonstrated to be a unique 3alpha-hydroxysteroid dehydrogenase (HSD) that can convert 5alpha-androstane-3alpha, 17beta-diol (3alpha-adiol) to dihydrotestosterone (DHT), whose affinity to the androgen receptor is 10(5)-fold higher than that of 3alpha-adiol. The catalytic efficiency of human SCHAD for this oxidative 3alpha-HSD reaction was estimated to be 164 min(-1) mM(-1), about 10-fold higher than that measured for the backward reaction. Thus, human brain SCHAD may function in androgen metabolism as a new kind of 3alpha-HSD by counteracting all other known 3alpha-HSDs, which would unidirectionally catalyze the reduction of DHT to the almost inactive 3alpha-adiol. Human SCHAD is identical to an amyloid-beta binding protein (ERAB) involved in Alzheimer's disease, which was previously reported to be associated with the endoplasmic reticulum. This protein is, in fact, localized in mitochondria, not endoplasmic reticulum, as evidenced by immunocytochemical studies and its noncleavable mitochondrial targeting sequence and lack of endoplasmic reticulum targeting signals or transmembrane segments. These results prompt the suggestion that the mitochondrion plays not only an essential role in the initial step of steroidogenesis, but also important roles in the intracellular homeostasis of sex steroid hormones. Northern blot analysis revealed that the human SCHAD gene is expressed in both gonadal and peripheral tissues including the prostate whose growth notably requires DHT, the most potent androgen. This study represents the first report of a 3alpha-HSD that could act to generate DHT from 3alpha-adiol and thereby maintain intracellular DHT levels. We propose that inhibitors of the 3alpha-HSD activity of human brain SCHAD could be useful for the treatment of benign prostatic hyperplasia and other disorders involving DHT metabolism, in combination with known inhibitors of steroid 5alpha-reductases.

Large-scale DNA-based typing of HLA-A and HLA-B at low resolution is highly accurate specific and reliable

DNA-based typing of HLA class I alleles of the HLA-A and HLA-B loci using sequence-specific oligonucleotide primers and/or probes has been used for the large-scale typing of individuals for the National Marrow Donor Program unrelated donor registry. Typing was performed by 16 laboratories at a low level of resolution (e.g. A*01, B*07). The results of blinded quality control analysis for the first 12 months of the project show the typing to be highly accurate, specific and reliable. The total error rate based on 11,545 HLA-A and 11,428 HLA-B assignments was 1.1% for HLA-A and 1.9% for HLA-B. This level of accuracy is particularly remarkable because the quality control samples could not be distinguished from 64,180 donor samples tested at the same time by the laboratories.

Platelet supernatant promotes proliferation of auricular chondrocytes and formation of chondrocyte mass

Recently proposed procedures for in vitro generation of new cartilage may be difficult to perform in humans because so many chondrocytes are needed for tissue engineering. In this study the authors investigated new, efficient, low-cost techniques for the isolation and culture of chondrocytes from the ear cartilage of the rabbit. They performed a low-density monolayer culture with a low concentration (0.5%, 1%) of human platelet supernatant and observed cell proliferation (seeding efficiency, deoxyribonucleic acid synthesis), matrix synthesis (glycosaminoglycan synthesis), and the expression of type I and type II collagen (reverse transcriptase polymerase chain reaction). Seeding efficiency was increased in 1% of platelet supernatant-treated cultures by two to three times compared with untreated controls. One percent platelet supernatant had increased the incorporation of [3H]-thymidine by 1.9 to 2.5 times at 72 hours compared with controls. Glycosaminoglycan synthesis was increased in platelet supernatant-treated chondrocytes at 96 hours compared with controls. Chondrocytes treated with 1% platelet supernatant showed a decreased expression of the type II collagen gene. Supplementation with a high concentration (10%) of the platelet supernatant provided the conditions for in vitro chondrocyte mass formation. These results indicate that proliferation and matrix synthesis of auricular chondrocytes is stimulated by a low concentration of platelet supernatant. On the other hand, chondrocytes were immobilized by a high concentration of platelet supernatant. Platelet supernatant may be useful as an inexpensive autologous source of multiple growth factors to enhance chondrocyte proliferation, and also may play the role of scaffold for chondrocytes. Additional investigation is underway to generate culture conditions that promote the differentiation as well as the proliferation of chondrocytes.

[Role of nitric oxide in the reflex of raising biliary pressure]

Raising the biliary tract pressure from the baseline to 4 kPa significantly decreases arterial blood pressure and myoelectric activity of sphincter of Oddi (SO) (bile duct-arterial blood pressure reflex), which is sometimes associated with the disappearance of phasic myoelectric activity of SO (bile duct-SO reflex). Thirty-two rabbits were used to investigate the role of nitric oxide (NO) in these reflexes. On the base of increased myoelectric activity and arterial blood pressure by intravenous drip of 4 microgram/(kg.min) noradrenaline, raising the biliary tract pressure from the baseline to 4 kPa significantly decreased arterial blood pressure and myoelectric activity of SO. On the base of increased myoelectric activity and arterial blood pressure by intravenous injection of 10 mg/kg L-NNA, the bile duct-arterial blood pressure reflex disappeared in all the rabbits, but the bile duct-SO reflex disappeared only in a population of (3/8) and obviously decreased in the remaining ones (5/8) during raising biliary pressure from the baseline to 4 kPa. The bile duct-SO reflex after preceding local perfusion of L-NNA was similar to that after preceding intravenous injection of L-NNA, but bile duct-arterial blood pressure reflex still appeared. These findings suggest that both of these two reflexes are caused by the tension stimulation to the receptive area of the biliary tract, and may be mediated by NO.

Intrinsic alcohol dehydrogenase and hydroxysteroid dehydrogenase activities of human mitochondrial short-chain L-3-hydroxyacyl-CoA dehydrogenase

The alcohol dehydrogenase (ADH) activity of human short-chain l-3-hydroxyacyl-CoA dehydrogenase (SCHAD) has been characterized kinetically. The k(cat) of the purified enzyme was estimated to be 2. 2 min(-1), with apparent K(m) values of 280 mM and 22microM for 2-propanol and NAD(+), respectively. The k(cat) of the ADH activity was three orders of magnitude less than the l-3-hydroxyacyl-CoA dehydrogenase activity but was comparable with that of the enzyme's hydroxysteroid dehydrogenase (HSD) activity for oxidizing 17beta-oestradiol [He, Merz, Mehta, Schulz and Yang (1999) J. Biol. Chem. 274, 15014-15019]. However, the k(cat) values of intrinsic ADH and HSD activities of human SCHAD were found to be two orders of magnitude less than those reported for endoplasmic-reticulum-associated amyloid beta-peptide-binding protein (ERAB) [Yan, Shi, Zhu, Fu, Zhu, Zhu, Gibson, Stern, Collison, Al-Mohanna et al. (1999) J. Biol. Chem. 274, 2145-2156]. Since human SCHAD and ERAB apparently possess identical amino acid sequences, their catalytic properties should be identical. The recombinant SCHAD has been confirmed to be the right gene product and not a mutant variant. Steady-state kinetic measurements and quantitative analyses reveal that assay conditions such as pH and concentrations of coenzyme and substrate do not account for the kinetic differences reported for ERAB and SCHAD. Rather problematic experimental procedures appear to be responsible for the unrealistically high catalytic rate constants of ERAB. Eliminating the confusion surrounding the catalytic properties of this important multifunctional enzyme paves the way for exploring its role(s) in the pathogenesis of Alzheimer's disease.

2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) inhibits nitric oxide production in cultured murine astrocytes

The level of nitrite accumulation in the culture media of astrocytes activated with lipopolysaccharide (LPS) and interferon-gamma (IFN) was decreased by pretreatment of cells with LY294002, a quercetin derivative developed for phosphatidylinositol-3-kinase (PI3K) inhibitor, in a dose-dependent manner. The expression of iNOS mRNA in the astrocytes was inhibited by LY294002, as revealed by reverse transcriptional polymerase chain reaction and agarose gel electrophoresis. The catalytic activity of astrocytic iNOS was also inhibited by LY294002. On the other hand, wortmannin which was known to enhance endotoxin-induced NO production in macrophages by inhibiting PI3K did not cause any significant change in the NO production and iNOS mRNA expression of the astrocytes. These results suggest that LY294002 suppresses NO production in the astrocytes through not only the inhibition of iNOS mRNA expression but also the inhibition of the iNOS activity and that PI3K is not involved in the inhibitory actions of LY294002.pc 1999 Academic Press@p$hr

The probability of HLA-C matching between patient and unrelated donor at the molecular level: estimations based on the linkage disequilibrium between DNA typed HLA-B and HLA-C alleles

BACKGROUND

Recent evidence suggests a more significant role of HLA-C as a target of alloreactions after bone marrow transplantation than previously suspected. Although linkage disequilibrium (LD) between HLA-B and -C serogroups is well documented, the level of LD at the allelic level is not known. In this study, we determine the LD between HLA-B and -C alleles and estimate the probability of molecular HLA-C matching between unrelated individuals who match for both HLA-B alleles.

METHODS

The study included 727 haplotypes from 849 individuals who were HLA-A, -B, -C and -DRB1 typed by high-resolution PCR-SSOP technique. Zelterman's statistic was used to test for global LD between HLA loci. LD between specific HLA-B and -C allelic combinations was calculated from their observed and expected frequencies in the study haplotypes. The probability of HLA-C matching for specific HLA-B allele was estimated from contingency table generated from the HLA-B and -C haplotypes.

RESULTS

HLA-C was found to exist in LD with HLA-A and -B, as well as -DRB1, loci; however, it was strongest between HLA-B and -C loci. A marked variability in the level of LD between specific HLA-B and -C alleles was noticed. A strong LD was seen in some allele pairs like B*0702-C*w0702, B*3501-Cw*0401, and B*0801-Cw*0701. The overall estimated probability of HLA-C matching between unrelated individuals that match for both HLA-B alleles is 42.25%. For 237 (72.9%) of 325 combinations involving the 25 commonest HLA-B alleles, the estimated probability that the HLA-B-matched unrelated individuals will match for both HLA-C alleles is less than 50%. In addition, a 100% probability of matching for both HLA-C alleles is expected only if both individuals bear either B*0801/ B*0801 or B*4901/B*4901 or B*0801/B*4901. Probability tables for common alleles are presented.

CONCLUSIONS

We conclude that, despite matching for both HLA-B alleles by high resolution DNA typing and the presence of a strong LD between HLA-B and HLA-C loci, unrelated individuals are more likely to mismatch rather than match for one or both HLA-C alleles.

Polyspecific self-reactive antibodies in individuals infected with human immunodeficiency virus facilitate T cell deletion and inhibit costimulatory accessory cell function

Self-reactive polyspecific IgG antibodies (PSAs) arise in human immunodeficiency virus (HIV)-seropositive subjects before they develop AIDS. Self-reactive PSA levels correlate with the destruction of CD8 T cells in HIV-infected individuals and mediate the antibody-dependent cellular toxicity-based destruction of human T cells in tissue culture. PSAs react across the species barrier and bind to T cell antigens in mice. Such reactivity with mouse lymphocytes was not detected in normal human serum. Injection of human PSA IgG causes massive T cell depletion in the spleen, lymph nodes, and thymus in mice: evidence that PSA IgG facilitates T cell destruction in vivo. In addition to facilitating macrophage cytotoxicity, self-reactive PSA IgG inhibits the macrophage-mediated activation of T cells with antigen receptor-specific monoclonal antibody or with antigen. Exogenous costimulatory stimuli or interleukin (IL)-12 can reverse the inhibition. In contrast, exogenous IL-10 mimics this inhibition. These data implicate PSA IgG as a pathogenic factor in the development of HIV disease.

Determination and clinical significance of plasma levels of prostaglandins in patients with acute brain injury

BACKGROUND

Models of brain injury in experimental animals have shown that the level of prostaglandins (PGs) is increased in damage brain tissue, and that PGs play an important role in secondary brain damage. Almost all previous studies of the relationship between PGs and brain injury have been carried out in animals. In the present study we show that the PGs change in humans with brain injury.

METHODS

The plasma levels of thromboxane B2, 6-Keto-PGF2alpha, prostaglandin F2alpha, and prostaglandin E2 were measured by radioimmunoassay on the 1st, 3rd, 7th, and 14th days after brain injury. The same measurements were made on a control group of 26 healthy volunteers.

RESULTS

The levels of all four PGs were elevated, most markedly in the first week, with levels remaining high in the second week in the severely injured. On the first day levels were, on average, three times those found in the controls, with a seven-fold rise in some of the severely injured patients. Dividing the patients into three groups according to outcome, it was found that if the PGs were markedly increased to begin with and remained high, death or permanent disability was likely. In the group with good outcome, the levels dropped steadily from the initial high levels. The T/K ratio was studied. It related closely to the severity of injury, being higher in more severe injuries and decreasing with recovery. In patients who did not recover, the ratio increased steadily to its highest value on the 7th day, and remained high at the 14th.

CONCLUSION

Changes in PGs levels were closely related to the brain injury severity and its outcome, and there was a marked disturbance of the levels of PGs, which therefore appears to be an important indicator of secondary brain damage.

HLA-A*30 alleles and associated haplotypes in the Korean population

HLA-A30 is one of the serologically characterized specificities and has been known to exhibit different haplotypic associations in different ethnic groups. This study reveals the presence of two HLA-A*30 alleles, A*3001 (31/48; 64.6%) and A*3004 (17/48; 35.4%), with each allele existing as a distinct haplotype in the Korean population. One haplotype, A*3001-Cw*0602-B*1302-DRB1*0701-DQA1*02-DQB1*02, found in 77.4% of A*3001-positive individuals is likely identical to the haplotype previously identified by serology in Asians and European Caucasians. A second haplo-type, A*3004-Cw*0802-B*1401-DRB1*0404-DQA1*03-DQB1*0402, found in 64.7% of A*3004-positive individuals has not previously been described. Conserved and distinct haplotypic associations of the two A*30 alleles imply that the two haplotypes may have evolved separately and are relatively new in this population.

HLA-B22 diversity including a novel B54 variant (B*5507) in the Korean population

Diversity in the HLA-B22 group was investigated in the Korean population using PCR-SSOP and DNA sequencing analyses. Allelic typing of the B22 gene was performed by gene amplification of the polymorphic exons 2 and 3 of the HLA-B genes from 91 B22 positive individuals followed by a hybridization assay using 63 digoxigenin-labelled probes. Five different SSOP patterns including an unexpected pattern were identified and correlated well with the observed serologic types and with data obtained from DNA sequencing analyses. Novel allele, B*5507, was identified from two unrelated individuals who exhibited standard B54 serologic reactivity but an unexpected SSOP pattern. The DNA sequence of B*5507 is identical to B*5502 in exons 2 and 3 except for a single nucleotide substitution at codon 45 (GAG-->GGG) altering glutamic acid to glycine. Among the already known B molecules, this substitution has been observed only in the B54 molecule encoded by B*5401 allele. This is the evidence that Gly-45 is a crucial site forming the B54 serologic epitope. Interestingly, both alleles (B*5401 and B*5507) exhibit strong association with Cw*0102. Along with previous data, B22 appears to be a very diverse group in the Korean population consisting of at least seven different alleles. B*5401, B*5502, and B*5601 are the most frequent alleles. B*5507, B*5501, B*5504, and B*5604 appear at lower frequencies. Data obtained from this study will be useful in hematopoietic stem cell donor searches as well as in determination of a typing strategy for the HLA-B22 types in this population.

Crystallization and preliminary diffraction data of 60-kDa glycosylated pollen isoallergens from Bermuda grass

Crystals grown from a 60-kDa isoallergen mixture of Bermuda grass pollen have been obtained in 30% PEG 4000 and 25% isopropanol. The crystals diffract beyond 2-A resolution and belong to a tetragonal space group with the unit cell dimensions a = b = 86 A and c = 310 A. The preferential crystal growth of the larger isoallergens with a blocked N-terminus indicates that crystallization can isolate proteins with compact conformation.

HLA-C disparity between patients and unrelated donors matched for HLA-A, -B, and -DRB1 alleles: impact of serological vs. DNA typing for HLA-A and -B loci

High incidences of graft failure, graft-vs.-host disease (GVHD), and serious infections following unrelated donor (URD) marrow transplantation, despite apparent human leukocyte antigen (HLA) identity, may reflect the presence of molecular disparities, including those for HLA-C alleles between the patient and the URD. The level of these disparities could be significant, because as many as 42 alleles are currently known for HLA-C locus. We studied 84 patients and 251 potential URDs to evaluate 1) the extent of HLA-C disparity between the patient and the URD identified by serology for HLA-A and -B and by DNA typing for -DRB1 and 2) the level of HLA-C disparity between patients and URDs matched by high-resolution DNA typing for HLA-A, -B, and -DRB1. The DNA typing was performed at the Memorial Sloan Kettering Cancer Center, and the serotyping was provided by the registries. Of 251 URDs matched by HLA-A and -B serology and -DRB1 (sA_sB_dnaDRB1 ); 94, 75, and 82 were 6/6, 5/6, and 4/6 matches, respectively. Of 94 sA_sB_dnaDRB1 6/6 URDs, 51 (54.3%) were matched for both HLA-C alleles. In contrast, 31 (41.3%) 5/6 (p=0.12) and 15 (18.3%) 4/6 (p < 0.01) sA_sB_dnaDRB1 URDs were matched for both HLA-C alleles. Following DNA typing for HLA-A and -B, 52 (55.3%) of 94 6/6, 30 (40%) of 75 5/6, and 25 (30.5%) of 82 4/6 sA_sB_dnaDRB1 URDs remained 6/6, 5/6, and 4/6 matches at the DNA level (dnaA_B_DRB1). HLA-C disparities continued to exist in the dnaA_B_DRB1 URD group. Of 54 dnaA_B_DRB1 6/6 URDs, 41 (75.9%) were matched for both HLA-C alleles. Only 45.3% of the 5/6 (p=0.01) and 22.2% of the 4/6 (p < 0.01) dnaA_B_DRB1 URDs were matched for both HLA-C alleles. In the 6/6 category, the frequency of HLA-C matching improved (75.9 vs. 54.3%; p=0.01) following DNA matching for HLA-A and -B. In comparison to mismatching for HLA-B locus, mismatching for either HLA-DRB1 or -A resulted in a lower odds ratio for HLA-C disparity. The presence of a common haplotype in the sA_sB_dnaDRBl (p=0.06) URD category improved the level of HLA-C matching. We identified alleles that are associated with high (B*1501, B*4402, B*5101, DRB1*0101, A*0201, A*1101, A*2301, and A*3201) or low (B*0702, B*0801, B*1302, B*3502, DRB1*0301, DRB1*1104, A*0101, A*3001, and A*6801) probability of HLA-C disparity. Overall, sA_sB_dnaDRB1 as well as dnaA_B_DRB1 matched URDs for non-Caucasian patients were more likely to have HLA-C disparity in comparison to the matched URDs of Caucasian patients. However, a high incidence of HLA-C disparities was identified even in the URDs for Caucasian patients. Whether the disparities demonstrated by this study contribute to the higher immunological complications noted following URD bone marrow transplantation is unclear. Outcome analysis and studies aimed at understanding the functional role of HLA-C may provide an answer.

Human brain short chain L-3-hydroxyacyl coenzyme A dehydrogenase is a single-domain multifunctional enzyme. Characterization of a novel 17beta-hydroxysteroid dehydrogenase

Human brain short chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) was found to catalyze the oxidation of 17beta-estradiol and dihydroandrosterone as well as alcohols. Mitochondria have been demonstrated to be the proper location of this NAD+-dependent dehydrogenase in cells, although its primary structure is identical to an amyloid beta-peptide binding protein reportedly associated with the endoplasmic reticulum (ERAB). This fatty acid beta-oxidation enzyme was identified as a novel 17beta-hydroxysteroid dehydrogenase responsible for the inactivation of sex steroid hormones. The catalytic rate constant of the purified enzyme was estimated to be 0.66 min-1 with apparent Km values of 43 and 50 microM for 17beta-estradiol and NAD+, respectively. The catalytic efficiency of this enzyme for the oxidation of 17beta-estradiol was comparable with that of peroxisomal 17beta-hydroxysteroid dehydrogenase type 4. As a result, the human SCHAD gene product, a single-domain multifunctional enzyme, appears to function in two different pathways of lipid metabolism. Because the catalytic functions of human brain short chain L-3-hydroxyacyl-CoA dehydrogenase could weaken the protective effects of estrogen and generate aldehydes in neurons, it is proposed that a high concentration of this enzyme in brain is a potential risk factor for Alzheimer's disease.

Cytochrome P450 1A1 genetic polymorphisms and risk of hepatocellular carcinoma among chronic hepatitis B carriers

Cigarette smoking has been associated with increased risk of hepatocellular carcinoma (HCC) in some epidemiological studies. Cytochrome P450 1A1 (CYP1A1) is involved in the biotransformation of tobacco-derived polycyclic aromatic hydrocarbons (PAHs) into carcinogenic metabolites. The aim of this study was to determine whether CYP1A1 polymorphisms were related to HCC risk among chronic hepatitis B virus (HBV) carriers. Genotypic variants of CYP1A1 were determined using polymerase chain reaction in 81 incident cases of HCC and 409 controls nested in a cohort study of 4841 male chronic HBV carriers. No overall association between CYP1A1 genotypes and HCC was observed. The presence of the Mspl (odds ratio (OR) 3.15, P = 0.0196) or Ile-Val (OR 1.99, P = 0.0855) variant allele of CYP1A1 increased HCC risk among smokers, but posed no increased risk among non-smokers. The smoking-related HCC risk was most pronounced among those who had a susceptible allele of the CYP1A1 and a deficient genotype of glutathione S-transferase M1, which detoxifies PAH electrophilic metabolites produced by CYP1A1. In the absence of the Ile-Val variant allele, the Mspl polymorphism was still associated with smoking-related HCC. This study suggests that tobacco-derived PAHs play a role in HCC risk among chronic HBV carriers, and CYP1A1 polymorphism is an important modulator of the hepatocarcinogenic effect of PAHs. The Mspl and Ile-Val polymorphisms of CYP1A1 may have different mechanisms for increasing susceptibility to smoking-related HCC.

Polarizing microscopy of eyespot of Chlamydomonas: in situ observation of its location, orientation, and multiplication

The eyespot in the cell of Chlamydomonas reinhardtii has been found to appear as a bright spot under the cross polar setting of a polarizing microscope. This was confirmed by isolating the eyespot from a homogenate of wall-deficient mutant cw-15, and by observing it under a polarizing microscope. Thus, the eyespot was proved to be a strongly birefringent body. Next, gametes (mt+ and mt-) of 137c strain were prepared by cultivating it in a low-nitrogen (NH4Cl) medium. Here, every cell shows only one (and never more than one) birefringent spot. The birefringent eyespot was located always near the surface on the "equator," that is, at the farthest point from the "meridionial" cell-axis that is defined as the bisector of the two flagella projected out from the cell surface. It was shown, in addition, that the optic axis of this birefringent eyespot is oriented in the cell always along the parallel direction of the cell axis defined above. Thus, the polarizing microscopy has been shown to provide a powerful method for in vivo, in situ pursuit of the eyespot of Chlamydomonas.