Oriental double eyelid: a limited-incision technique

Although there are many procedures reported in the literature regarding the double-eyelid operation, they can be categorized basically into two groups: nonincision and incision. Conventionally, the nonincision technique has been shown to produce little postoperative edema. However, the probability of the fold disappearing is high, and this technique cannot be performed in patients with fatty eyelids. Conversely, the incision technique has contrary characteristics. As an alternative option, the author developed a limited-incision single-stitch technique that minimizes tissue injury and provides adequate adhesion for fold formation. With this method, a small single incision (3-4 mm) is made in the upper eyelid. Through the incision, the orbital fat can be removed, when indicated. Under direct vision, a levator aponeurosis or tarsus is attached to the muscle and the dermis of the pretarsal margin by a single stitch. This technique gives a durable, natural fold; has a short recovery time; and can be applied to patients with fatty eyelids. This method has the merits of both the incision and the nonincision techniques, and avoids the disadvantages of both procedures.

Effect on human attention of exposure to the electromagnetic field emitted by mobile phones

This study examined the effect of exposure to the electromagnetic field emitted by mobile phones on human attention. Three measures of attention were administered to 72 teenagers, 37 of whom were mobile phone users. The results showed that the mobile phone users performed better on one of the three measures of attention than did the non-mobile phone users. The results suggest that exposure to the electromagnetic field emitted by mobile phones may have a mild facilitating effect on attention functions, which is consistent with previous observations that exposure to the electromagnetic field has a facilitating effect on cognitive processing. The possibility that mobile phone users may be naturally better at multiple tasking tasks was discussed.

Validation of DNA-based HLA-A and HLA-B testing of volunteers for a bone marrow registry through parallel testing with serology

A total of 42,160 individuals were typed for HLA-A and HLA-B by both serology and PCR-based typing. The HLA assignments included all of the known serological equivalents. The majority of the individuals (99.9%) were from U.S. minority population groups. The serologic typing was performed between 1993 and 1997 at the time of recruitment for the National Bone Marrow Program (NMDP) registry. The polymerase chain reaction (PCR)-based typing was carried out in two phases. In phase I, DNA typing was performed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or PCR using sequence-specific primers (PCR-SSP) without knowledge of the serologic assignments. Discrepancies were identified between the serologic and DNA assignments in 24% of the volunteers (8% of volunteers differed for only HLA-A assignments, 13% for HLA-B, and 3% for both HLA-A and -B) and a potential explanation was assigned each discrepant serology/DNA pair. In phase II, a random sampling scheme was used to select a statistically significant number of individuals for repeat DNA typing from each of these categories. The categories included antigens missed by serology, nonexpressed (null) alleles, PCR amplification failures, misassignment of antigens and nomenclature issues. Only a single individual was found to carry a null allele. DNA-based testing correctly typed nearly 99% of the donors at HLA-A, more than 98% at HLA-B, and more than 97% at both HLA-A and -B validating this methodology for registry typing.

The involvement of PI 3-K/Akt-dependent up-regulation of Mcl-1 in the prevention of apoptosis of Hep3B cells by interleukin-6

Interleukin-6 (IL-6) is a pleitrophic cytokine that not only regulates growth and differentiation of many cell types, but also induces production of acute phase proteins (AAP) in hepatocytes. Our previous works have demonstrated that both PI 3-K/Akt and STAT3 pathways were concomitantly activated and cooperatively mediated the anti-apoptotic effect of IL-6. This investigation reports that IL-6 protected cells against apoptosis induced by a variety of agents including, TGF-beta, UV and retinoic acid (RA) in Hep3B cells, suggesting that IL-6 is a fundamental determinant of hepatic cell survival. Mcl-1, but not other Bcl-2 family members, was rapidly up-regulated by IL-6, with a peak (approximately 3-4-fold) appearing at 4 h. Transient transfection of cells with a mcl-1 antisense vector, resulting in a 50-60% reduction of the anti-apoptotic effect of IL-6, indicating that Mcl-1 is a downstream effector of IL-6. Which signaling pathway transduced by IL-6 responsible for the Mcl-1 up-regulation was further investigated. In Hep3B cells, the JAK/STAT3, ERK, and PI 3-K/Akt pathways were activated by IL-6 stimulation. Blocking JAK/STAT3 activation with a dominant-negative mutant STAT3F or a JAK inhibitor AG490 could not influence IL-6-mediated Mcl-1 up-regulation. Similarly, PD98059 treatment, a MEK specific inhibitor, also failed to inhibit Mcl-1 expression. However, the IL-6-induced Mcl-1 up-regulation was effectively attenuated in the presence of PI 3-K inhibitors, LY294002 and wortmannin. Expression of dominant-negative Akt, but not Etk, could abrogate the IL-6-induced increase of Mcl-1. In conclusion, our results suggest that the anti-apoptotic effect of IL-6 is mediated, at least in part, by Mcl-1 expression and that is mainly through the PI 3-K/ Akt-dependent pathway.

Molecular cloning, modeling, and localization of rat type 10 17beta-hydroxysteroid dehydrogenase

Rat and mouse complementary DNAs of type 10 17beta-hydroxysteroid dehydrogenase were cloned and sequenced. The mouse cDNA clone's sequence corrected the previously published nucleotide and amino acid sequence of mouse endoplasmic reticulum-associated beta-amyloid-binding protein. A subunit of the rat enzyme consists of 261 amino acid residues with a calculated molecular mass of 27250 Da. Compared with its human counterpart, rat 17betaHSD type 10 shows 88% identity. Mouse 17betaHSD type 10 is composed of 261 amino acid residues with a calculated molecular mass of 27274 Da. There is 95% identity between the two rodent enzymes. A stereostructure model of rat 17betaHSD type 10 was constructed based on its amino acid sequence. Similar to human type 10 17betaHSD, the rodent enzymes also displayed relatively higher 3alphaHSD activity than 17betaHSD activity. Intracellular localization of rat 17betaHSD type 10 has been determined by subcellular fractionation and confocal microscopy studies. The results unequivocally establish that this is a nuclear gene-encoded mitochondrial enzyme, and that this 17betaHSD is not associated with the endoplasmic reticulum. The unique location distinguishes type 10 from other types of 17beta-hydroxysteroid dehydrogenases.

Androgen-receptor gene CAG repeats, plasma testosterone levels, and risk of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Worldwide, hepatocellular carcinoma (HCC) is more prevalent in men than in women, suggesting that sex hormones and/or X-chromosome-linked genes may be involved in hepatocarcinogenesis. We investigated the association of a trinucleotide (CAG) repeat in the androgen receptor (AR) gene (located on the X chromosome) termed "AR-CAG repeats," levels of plasma testosterone, and the risk of HCC in Taiwanese men. Chronic hepatitis B virus (HBV) infection, which is associated with risk of HCC, is hyperendemic in Taiwan.

METHODS

We compared the number of AR-CAG repeats in 285 HBV carriers with HCC and in 349 HBV carriers without HCC. We also conducted a nested case--control study on participants in a cohort study. Blood was collected prospectively from 110 case patients and 239 control subjects and was used to determine the number of AR-CAG repeats and plasma testosterone level. All statistical tests were two-sided.

RESULTS

The overall odds ratio (OR) for HCC was 1.72 (95% confidence interval [CI] = 1.03--2.89) for HBV carriers with 20 or fewer AR-CAG repeats compared with those with more than 24 repeats. This association was observed only in patients with late-onset HCC (OR = 2.37; 95% CI = 1.28--4.38). In the nested case-control study, HBV carriers in the highest tertile of testosterone levels had a statistically significantly increased risk of HCC (OR = 2.06; 95% CI = 1.14--3.70) compared with those in the lowest tertile. Elevated testosterone was more strongly associated with early-onset (OR = 4.67; 95% CI = 1.41--15.38) than late-onset disease. HBV carriers with 20 or fewer AR-CAG repeats and higher testosterone levels had a fourfold increase in HCC risk compared with those with more than 24 repeats and testosterone levels in the lowest tertile.

CONCLUSIONS

Higher levels of androgen signaling, reflected by higher testosterone levels and 20 or fewer AR-CAG repeats, may be associated with an increased risk of HBV-related HCC in men.

Cloning and characterization of a new member of the T-box gene family

The T-box is a strongly conserved protein domain, 174 to 186 amino acids in length, that binds DNA. Many genes from many species have been shown to encode T-box domain-containing proteins. Here we report the cloning and characterization of a novel T-box gene, TBX21. The human cDNA contains an open reading frame encoding a 535-amino-acid protein with a predicted molecular mass of 58.3 kDa. Except for the T-box sequence, database searches revealed no significant homology to any known sequences at the nucleotide or protein level. In addition to the human cDNA sequence, we report the cDNA sequence of the murine homologue, the structure and organization of the murine Tbx21 gene, and its localization to mouse chromosome 11. TBX21 expression was detected in peripheral blood lymphocytes, spleen, lung, and natural killer cells.

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.

Role of N-acetyltransferase polymorphisms in hepatitis B related hepatocellular carcinoma: impact of smoking on risk

BACKGROUND

Persistent infection with hepatitis B virus (HBV) causes chronic phasic necroinflammation and regenerative proliferation in the liver. The sustained hepatocellular proliferation may render chronic HBV carriers more susceptible to the effects of environmental carcinogens. Aromatic amines are potential hepatocarcinogens in humans. N-acetyltransferase (NAT) is involved in the metabolic activation and detoxification of these compounds.

AIMS

To investigate if genetic polymorphisms in N-acetylation are related to hepatocellular carcinoma (HCC) among chronic HBV carriers.

METHODS

Genotyping of NAT1 and NAT2 was performed using polymerase chain reaction-restriction fragment length polymorphism on peripheral leucocyte DNA from 151 incident cases of HCC and 211 controls. All subjects were male, and were chronic HBV surface antigen carriers.

RESULTS

A significant association between NAT2 genetic polymorphism and HCC was observed among chronic HBV carriers who were smokers but not among those who were non-smokers. For smoking HBV carriers, the odds ratios of developing HCC for those heterozygous and homozygous for the NAT2*4 functional allele compared with those without any copies of the functional allele (reference group) were 2.67 (95% confidence interval 1.15-6.22) and 2.58 (95% confidence interval 1.04-6.43), respectively. The interaction between cigarette smoking and the presence of the NAT2*4 allele just failed to reach statistical significance (p=0.06). No association between NAT1 genotype and HCC was evident overall or within the smoking stratified subgroups.

CONCLUSIONS

Our results suggest that NAT2 activity may be particularly critical in smoking related hepatocarcinogenesis among chronic HBV carriers. Our data also indirectly support a role for tobacco smoke derived aromatic amines in the aetiology of HCC.

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.