Egg white proteins and their potential use in food processing or as nutraceutical and pharmaceutical agents--a review

Egg white contains many functionally important proteins. Ovalbumin (54%), ovotransferrin (12%), ovomucoid (11%), ovomucin (3.5%), and lysozyme (3.5%) are among the major proteins that have high potentials for industrial applications if separated. The separation methods for these proteins from egg white have been developed since early 1900, but preparation methods of these proteins for commercial applications are still under development. Simplicity and scalability of the methods, use of nontoxic chemicals for the separation, and sequential separation for multiple proteins are very important criteria for the commercial production and application of these proteins. The separated proteins can be used in food and pharmaceutical industry as is or after modifications with enzymes. Ovotransferrin is used as a metal transporter, antimicrobial, or anticancer agent, whereas lysozyme is mainly used as a food preservative. Ovalbumin is widely used as a nutrient supplement and ovomucin as a tumor suppression agent. Ovomucoid is the major egg allergen but can inhibit the growth of tumors, and thus can be used as an anticancer agent. Hydrolyzed peptides from these proteins showed very good angiotensin I converting enzyme inhibitory, anticancer, metal binding, and antioxidant activities. Therefore, separation of egg white proteins and the productions of bioactive peptides from egg white proteins are emerging areas with many new applications.

Direct functional interactions between insulin-like growth factor-binding protein-3 and retinoid X receptor-alpha regulate transcriptional signaling and apoptosis

Insulin-like growth factor-binding protein (IGFBP)-3 regulates apoptosis in an IGF-independent fashion and has been shown to localize to nuclei. We cloned the nuclear receptor retinoid X receptor-alpha(RXR-alpha) as an IGFBP-3 protein partner in a yeast two-hybrid screen. Multiple methodologies showed that IGFBP-3 and RXR-alpha bind each other within the nucleus. IGFBP-3-induced apoptosis was abolished in RXR-alpha-knockout cells. IGFBP-3 and RXR ligands were additive in inducing apoptosis in prostate cancer cells. IGFBP-3 enhanced RXR response element and inhibited RARE signaling. Thus, RXR-alpha-IGFBP-3 interaction leads to modulation of the transcriptional activity of RXR-alpha and is essential for mediating the effects of IGFBP-3 on apoptosis.

Electrical conduction through poly(dA)-poly(dT) and poly(dG)-poly(dC) DNA molecules

We report direct measurements of electrical transport through poly(dA)-poly(dT) and poly(dG)-poly(dC) DNA molecules containing identical base pairs. The observed experimental results suggest that electrical transport through DNA molecules occurs by polaron hopping. We have also investigated the effect of gate voltage on the current-voltage curve. It demonstrates the possibility of a DNA field-effect transistor operating at room temperature. Moreover, the gate-voltage dependent transport measurements show that poly(dA)-poly(dT) behaves as an n-type semiconductor, whereas poly(dG)-poly(dC) behaves as a p-type semiconductor.

Novel osmotin inhibits SREBP2 via the AdipoR1/AMPK/SIRT1 pathway to improve Alzheimer's disease neuropathological deficits

Extensive evidence has indicated that a high rate of cholesterol biogenesis and abnormal neuronal energy metabolism play key roles in Alzheimer's disease (AD) pathogenesis. Here, for we believe the first time, we used osmotin, a plant protein homolog of mammalian adiponectin, to determine its therapeutic efficacy in different AD models. Our results reveal that osmotin treatment modulated adiponectin receptor 1 (AdipoR1), significantly induced AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1) activation and reduced SREBP2 (sterol regulatory element-binding protein 2) expression in both in vitro and in vivo AD models and in Adipo^-/- mice. Via the AdipoR1/AMPK/SIRT1/SREBP2 signaling pathway, osmotin significantly diminished amyloidogenic Aβ production, abundance and aggregation, accompanied by improved pre- and post-synaptic dysfunction, cognitive impairment, memory deficits and, most importantly, reversed the suppression of long-term potentiation in AD mice. Interestingly, AdipoR1, AMPK and SIRT1 silencing not only abolished osmotin capability but also further enhanced AD pathology by increasing SREBP2, amyloid precursor protein (APP) and β-secretase (BACE1) expression and the levels of toxic Aβ production. However, the opposite was true for SREBP2 when silenced using small interfering RNA in APPswe/ind-transfected SH-SY5Y cells. Similarly, osmotin treatment also enhanced the non-amyloidogenic pathway by activating the α-secretase gene that is, ADAM10, in an AMPK/SIRT1-dependent manner. These results suggest that osmotin or osmotin-based therapeutic agents might be potential candidates for AD treatment.

Autotaxin (ATX), a potent tumor motogen, augments invasive and metastatic potential of ras-transformed cells

Autotaxin (ATX), an exo-nucleotide pyrophosphatase and phosphodiesterase, was originally isolated as a potent stimulator of tumor cell motility. In order to study whether ATX expression affects motility-dependent processes such as invasion and metastasis, we stably transfected full-length ATX cDNA into two non-expressing cell lines, parental and ras-transformed NIH3T3 (clone7) cells. The effect of ATX secretion on in vitro cell motility was variable. The ras-transformed, ATX-secreting subclones had enhanced motility to ATX as chemoattractant, but there was little difference in the motility responses of NIH3T3 cells transfected with atx, an inactive mutant gene, or empty vector. In MatrigelTM invasion assays, all subclones, which secreted enzymatically active ATX, demonstrated greater spontaneous and ATX-stimulated invasion than appropriate controls. This difference in invasiveness was not caused by differences in gelatinase production, which was constant within each group of transfectants. In vivo studies with athymic nude mice demonstrated that injection of atx-transfected NIH3T3 cells resulted in a weak tumorigenic capacity with few experimental metastases. Combination of ATX expression with ras transformation produced cells with greatly amplified tumorigenesis and metastatic potential compared to ras-transformed controls. Thus, ATX appears to augment cellular characteristics necessary for tumor aggressiveness.

Autotaxin is an exoenzyme possessing 5'-nucleotide phosphodiesterase/ATP pyrophosphatase and ATPase activities

Autotaxin (ATX) is an extracellular enzyme and an autocrine motility factor that stimulates pertussis toxin-sensitive chemotaxis in human melanoma cells at picomolar to nanomolar concentrations. This 125-kDa glycoprotein contains a peptide sequence identified as the catalytic site in type I alkaline phosphodiesterases (PDEs), and it possesses 5'-nucleotide PDE (EC 3.1.4.1) activity (Stracke, M. L., Krutzsch, H. C., Unsworth, E. J., Arestad, A., Cioce, V., Schiffmann, E., and Liotta, L. (1992) J. Biol. Chem. 267, 2524-2529; Murata, J., Lee, H. Y., Clair, T., Krutsch, H. C., Arestad, A. A., Sobel, M. E., Liotta, L. A., and Stracke, M. L. (1994) J. Biol. Chem. 269, 30479-30484). ATX binds ATP and is phosphorylated only on threonine. Thr210 at the PDE active site of ATX is required for phosphorylation, 5'-nucleotide PDE, and motility-stimulating activities (Lee, H. Y., Clair, T., Mulvaney, P. T., Woodhouse, E. C., Aznavoorian, S., Liotta, L. A., and Stracke, M. L. (1996) J. Biol. Chem. 271, 24408-24412). In this article we report that the phosphorylation of ATX is a transient event, being stable at 0 degrees C but unstable at 37 degrees C, and that ATX has adenosine-5'-triphosphatase (ATPase; EC 3.6.1.3) and ATP pyrophosphatase (EC 3.6.1.8) activities. Thus ATX catalyzes the hydrolysis of the phosphodiester bond on either side of the beta-phosphate of ATP. ATX also catalyzes the hydrolysis of GTP to GDP and GMP, of either AMP or PPi to Pi, and the hydrolysis of NAD to AMP, and each of these substrates can serve as a phosphate donor in the phosphorylation of ATX. ATX possesses no detectable protein kinase activity toward histone, myelin basic protein, or casein. These results lead to the proposal that ATX is capable of at least two alternative reaction mechanisms, threonine (T-type) ATPase and 5'-nucleotide PDE/ATP pyrophosphatase, with a common site (Thr210) for the formation of covalently bound reaction intermediates threonine phosphate and threonine adenylate, respectively.

Antiobesity effect of trans-10,cis-12-conjugated linoleic acid-producing Lactobacillus plantarum PL62 on diet-induced obese mice

AIMS

To observe the antiobesity activity of trans-10,cis-12-conjugated linoleic acid (CLA)-producing lactobacillus in mice.

METHODS AND RESULTS

Lactobacillus plantarum PL62, which can grow in the presence of linoleic acid, was selected and studied. The culture supernatant of Lact. plantarum PL62 contained trans-10,cis-12-conjugated linoleic acid (6.4 microg ml(-1)), and the crude enzyme prepared from washed cells produced trans-10,cis-12 CLA (1395 microg mg(-1) protein). Lact. plantarum PL62 reduced the weights of epididymal, inguinal, mesenteric, and perirenal white adipose tissues and significantly reduced the blood levels of total glucose and body weights of mice (P<0.01).

CONCLUSIONS

trans-10,cis-12-CLA-producing Lact. plantarum PL62 can exert the same antiobesity activity as trans-10,cis-12-CLA in mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

trans-10,cis-12-CLA-producing Lactobacillus can be a replacement for CLA for obesity treatment via the continuous production of trans-10,cis-12-CLA. The results provide a novel opportunity to develop foods with antiobesity activity.

Precise spatial positioning of chromosomes during prometaphase: evidence for chromosomal order

The relative locations of several chromosomes within wheel-shaped prometaphase chromosome rosettes of human fibroblasts and HeLa cells were determined with fluorescence hybridization. Homologs were consistently positioned on opposite sides of the rosette, which suggests that chromosomes are separated into two haploid sets, each derived from one parent. The relative locations of chromosomes on the rosette were mapped by dual hybridizations. The data suggest that the chromosome orders within the two haploid sets are antiparallel. This chromosome arrangement in human cells appears to be both independent of cell type- and species-specific and may influence chromosome topology throughout the cell cycle.

Anti-angiogenic activity of triterpene acids

Ursolic acid (UA) and oleanolic acid (OA) were examined for anti-angiogenic activities by using the chick embryo chorioallantoic membrane (CAM) assay. The presence of UA or OA inhibited angiogenesis in a dose-dependent manner; the doses required for half-maximal inhibition (ID50) were 5 micrograms and 40 micrograms per CAM, respectively. UA was a more potent angiogenic inhibitor than OA. We also tested for inhibitory effect on the proliferation of bovine aortic endothelial cell. They effectively inhibited the proliferation of bovine aortic endothelial cell in a concentration-dependent manner. The IC50 values of anti-proliferative effects were determined to be 5 microM for UA and 20 microM for OA. Based on these results, we speculated that the inhibitory effects on bovine aortic endothelial cell proliferation of UA and OA might be important for anti-angiogenesis.

The cytoskeletal/non-muscle isoform of alpha-actinin is phosphorylated on its actin-binding domain by the focal adhesion kinase

alpha-Actinin is tyrosine-phosphorylated in activated human platelets (Izaguirre, G., Aguirre, L., Ji, P., Aneskievich, B., and Haimovich, B. (1999) J. Biol. Chem. 274, 37012--37020). Analysis of platelet RNA by reverse transcription-polymerase chain reaction revealed that alpha-actinin expressed in platelets is identical to the cytoskeletal/non-muscle isoform. A construct of this isoform containing a His(6) tag at the amino terminus was generated. Robust tyrosine phosphorylation of the recombinant protein was detected in cells treated with the tyrosine phosphatase inhibitor vanadate. The tyrosine phosphorylation site was localized to the amino-terminal domain by proteolytic digestion. A recombinant alpha-actinin protein containing a Tyr --> Phe mutation at position 12 (Y12F) was no longer phosphorylated when expressed in vanadate-treated cells, indicating that tyrosine 12 is the site of phosphorylation. The wild type recombinant protein was not phosphorylated in cells lacking the focal adhesion kinase (FAK). Re-expression of FAK in these cells restored alpha-actinin phosphorylation. Purified wild type alpha-actinin, but not the Y12F mutant, was phosphorylated in vitro by wild type as well as a Phe-397 mutant of FAK. In contrast, no phosphorylation was detected in the presence of a kinase-dead FAK. Tyrosine phosphorylation reduced the amount of alpha-actinin that cosedimented with actin filaments. These results establish that alpha-actinin is a direct substrate for FAK and suggest that alpha-actinin mediates FAK-dependent signals that could impact the physical properties of the cytoskeleton.

Hydrogen peroxide activates p70(S6k) signaling pathway

We investigated a possible role of reactive oxygen species (ROS) in p70(S6k) activation, which plays an important role in the progression of cells from G(0)/G(1) to S phase of the cell cycle by translational up-regulation of a family of mRNA transcripts that encode for components of the protein synthetic machinery. Treatment of mouse epidermal cell JB6 with H(2)O(2) generated extracellularly by glucose/glucose oxidase led to the activation of p70(S6k) and p90(Rsk) and to phosphorylation of p42(MAPK)/p44(MAPK). The activation of p70(S6k) and p90(Rsk) was dose-dependent and transient, maximal activities being in extracts treated for 15 and 30 min, respectively. Further characterization of ROS-induced activation of p70(S6k) using specific inhibitors for p70(S6k) signaling pathway, rapamycin, and wortmannin revealed that ROS acted upstream of the rapamycin-sensitive component FRAP/RAFT and wortmannin-sensitive component phosphatidylinositol 3-kinase, because both inhibitors caused the inhibition of ROS-induced p70(S6k) activity. In addition, Ca(2+) chelation also inhibited ROS-induced activation of p70(S6k), indicating that Ca(2+) is a mediator of p70(S6k) activation by ROS. However, down-regulation of 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive protein kinase C (PKC) by chronic pretreatment with TPA or a specific PKC inhibitor Ro-31-8220 did not block the activation of p70(S6k) by ROS, indicating that the activation of TPA-responsive PKC was not required for stimulation of p70(S6k) activity by H(2)O(2) in JB6 cells. Exposure of JB6 cells to platelet-derived growth factor or epidermal growth factor led to a rapid increase in H(2)O(2), phosphorylation, and activation of p70(S6k), which were antagonized by the pretreatment of catalase. Taken together, the results suggest that ROS act as a messenger in growth factor-induced p70(S6k) signaling pathway.

Lysophosphatidic acid augments human hepatocellular carcinoma cell invasion through LPA1 receptor and MMP-9 expression

Lysophosphatidic acid (LPA), produced extracellularly by autotaxin (ATX), has diverse biological activities implicated in tumor initiation and progression, including increasing cell survival, angiogenesis, invasion and metastasis. ATX, LPA and the matrix metalloproteinase (MMP)-9 have all been implicated in hepatocellular carcinoma (HCC) invasion and metastasis. We, thus sought to determine whether ATX with subsequent LPA production and action, including induction of MMP-9 could provide a unifying mechanism. ATX transcripts and LPA receptor type 1 (LPA1) protein are elevated in HCC compared with normal tissues. Silencing or pharmacological inhibition of LPA1 significantly attenuated LPA-induced MMP-9 expression and HCC cell invasion. Further, reducing MMP-9 activity or expression significantly inhibits LPA-induced HCC cell invasion, demonstrating that MMP-9 is downstream of LPA1. Inhibition of phosphoinositide-3 kinase (PI3K) signaling or dominant-negative mutants of protein kinase Cδ and p38 mitogen-activated protein kinase (MAPK) abrogated LPA-induced MMP-9 expression and subsequent invasion. We thus demonstrate a mechanistic cascade of ATX-producing LPA with LPA activating LPA1 and inducing MMP-9 through coordinate activation of the PI3K and the p38 MPAK signaling cascades, providing novel biomarkers and potential therapeutic targets for HCC.

Characteristic immunostimulation by angelan isolated from Angelica gigas Nakai

The immunopharmacological characteristics of angelan, a polysaccharide purified from Angelica gigas Nakai, were investigated in relation to the specificity to immune cells. The treatment of angelan increased the expression of IL-2, IL-4, IL-6, and IFN-gamma. The expression of IL-6 and IFN-gamma was rapidly augmented but that of IL-2 responded later. In the case of IL-4, angelan stimulated at early time after exposure but down-regulated thereafter. These results suggested that macrophages and natural killer cells involved in nonspecific immunity were primarily activated and helper T cells were secondarily affected by angelan. Angelan also had lympho-proliferative potential to B cells, specifically. The specificity of angelan was also elucidated in a cell fractionation experiment. The activated B cells by angelan also increased antibody production. The direct activation of B cells, macrophages, and accessory cells and the indirect activation of helper T cells coordinately increased immune functions such as in vitro and in vivo T-dependent immunization and antibody production. The experiment of host resistance to syngeneic tumors also showed that angelan potentiated the immune functions. In conclusion, angelan, a purified polysaccharide from an oriental herbal drug, showed characteristic immunostimulation, which was different from clinically used polysaccharides such as lentinan and PSK.

Multiple roles of mouse Numb in tuning developmental cell fates

BACKGROUND

Notch signaling regulates multiple differentiation processes and cell fate decisions during both invertebrate and vertebrate development. Numb encodes an intracellular protein that was shown in Drosophila to antagonize Notch signaling at binary cell fate decisions of certain cell lineages. Although overexpression experiments suggested that Numb might also antagonize some Notch activity in vertebrates, the developmental processes in which Numb is involved remained elusive.

RESULTS

We generated mice with a homozygous inactivation of Numb. These mice died before embryonic day E11.5, probably because of defects in angiogenic remodeling and placental dysfunction. Mutant embryos had an open anterior neural tube and impaired neuronal differentiation within the developing cranial central nervous system (CNS). In the developing spinal cord, the number of differentiated motoneurons was reduced. Within the peripheral nervous system (PNS), ganglia of cranial sensory neurons were formed. Trunk neural crest cells migrated and differentiated into sympathetic neurons. In contrast, a selective differentiation anomaly was observed in dorsal root ganglia, where neural crest--derived progenitor cells had migrated normally to form ganglionic structures, but failed to differentiate into sensory neurons.

CONCLUSIONS

Mouse Numb is involved in multiple developmental processes and required for cell fate tuning in a variety of lineages. In the nervous system, Numb is required for the generation of a large subset of neuronal lineages. The restricted requirement of Numb during neural development in the mouse suggests that in some neuronal lineages, Notch signaling may be regulated independently of Numb.

Epidemiological survey of oral submucous fibrosis and leukoplakia in aborigines of Taiwan

A population-based survey was designed to investigate the prevalence of areca/betel quid chewing, oral submucous fibrosis and leukoplakia in a typical aboriginal community of southern Taiwan. Three hundred and twelve people 20 years of age or older were collected in the study. The prevalence of chewing areca/betel quid was 69.5%, with an average of 17.3 portions a day for an average 24.4 years. More women (78.7%) than men (60.6%) chewed areca/betel quid. The prevalences of oral submucous fibrosis and leukoplakia were 17.6% and 24.4%, respectively. It was found that the odds ratio for chewing areca/betel quid and having at least one of the above oral mucosal lesions was 8.21. Any additional smoking or drinking habits were not significant for having oral mucosal lesions. Although the areca/betel quid in Taiwan does not contain any tobacco, a significant association was still identified between areca/betel quid chewing and oral mucosal lesions.

Transcriptional repression of the transforming growth factor-beta type I receptor gene by DNA methylation results in the development of TGF-beta resistance in human gastric cancer

The transforming growth factor-beta (TGF-beta) signaling pathway subserves an essential tumor suppressor function in various cell types. A heteromeric complex composed of TGF-beta type I (RI) and type II (RII) receptors is required for TGF-beta signaling. We have identified a subset of human gastric cancer cell lines which are insensitive to TGF-beta and which express a low level of TGF-beta type I receptor mRNA relative to a gastric cancer cell line which is highly responsive to TGF-beta. Using these cells, we show that hypermethylation of a CpG island in the 5' region of the TGF-beta RI gene provides another potentially important mechanism of escape from negative growth control by TGF-beta. This hypermethylation was found in four of five human gastric cancer cell lines and five out of 40 (12.5%) primary tumors examined. In human gastric cancer cell lines, treatment with the demethylating agent, 5-aza-2'-deoxycytidine, resulted in increased expression of the TGF-beta RI gene, but not the RII gene. Transient transfection of an RI expression vector into the TGF-beta resistant SNU-601 cell line restores TGF-beta responsiveness. These findings suggest that one of the mechanisms of escape from autocrine or paracrine growth control by TGF-beta during carcinogenesis could involve aberrant methylation of CpG islands in the 5' region of the TGF-beta RI gene.

Sterilization effect of atmospheric plasma on Escherichia coli and Bacillus subtilis endospores

AIMS

Escherichia coli and Bacillus subtilis spores were treated with an atmospheric plasma mixture created by the ionization of helium and oxygen to investigate the inactivation efficiency of a low-temperature plasma below 70 degrees C.

METHODS AND RESULTS

An electrical discharge plasma was produced at a radio frequency (RF) of 13.56 MHz, connected to a perforated circular electrode with a discharge spacing of 1-15 mm. The discharge gas was helium with 0-2% oxygen. For the plasma treatment, a dried E. coli cell or B. subtilis endospore suspension on a cover-glass was exposed to oxygen downstream of the plasma from holes in an RF-powered electrode. The sterilization effect of the RF plasma was highest with 0.2% oxygen, corresponding to the maximum production of oxygen radicals.

CONCLUSIONS

Oxygen radicals generated by RF plasma are effective for the destruction of bacterial cells and endospores.

SIGNIFICANCE AND IMPACT OF THE STUDY

Low-temperature atmospheric plasma can be used for the disinfection of diverse objects, especially for the inactivation of bacterial endospores.

Preoperative assessment of gastric carcinoma: value of two-phase dynamic CT with mechanical iv. injection of contrast material

OBJECTIVE

The purpose of this study was to evaluate the utility of two-phase dynamic CT performed with mechanical IV injection of a bolus of contrast medium after oral intake of water in the preoperative staging of gastric cancers.

SUBJECTS AND METHODS

We performed incremental dynamic CT in 52 patients with pathologically proved gastric cancers. Dynamic CT findings were prospectively analyzed and correlated with surgical and histopathologic findings. A total of 150 ml of nonionic contrast medium was administered IV with a power injector at a flow rate of 5 ml/sec for 30 sec, and two-phase images were obtained at 30 sec (early phase) and 2 min (equilibrium phase) after the start of bolus injection.

RESULTS

Forty-one advanced gastric carcinomas showed a moderate to marked degree of heterogeneous enhancement in the early phase and homogeneous enhancement of the entire lesion in the equilibrium phase of dynamic CT. The primary tumors were correctly detected with dynamic CT in five (56%) of the nine early gastric cancers and in 41 (95%) of the 43 advanced gastric cancers. The overall detection rate of gastric cancers was 88% (46 of 52 cases). The accuracies of dynamic CT according to TNM staging in determining the depth of tumor invasion, the degree of serosal invasion, and regional lymph node metastasis were 65% (34 of 52 cases), 83% (38 of 46 cases), and 70% (32 of 46 cases), respectively.

CONCLUSION

Our findings show that two-phase incremental dynamic CT with mechanical IV injection of a bolus of contrast medium after oral intake of water improves the diagnostic accuracy of CT over that provided by conventional CT in the preoperative staging of gastric cancers.

A 20-year experience with vasovasostomy

A total of 624 of 699 vasovasostomy patients was followed during the last 20 years. Better results were obtained when there was shorter duration of obstruction, bilateral straight vas-to-straight was anastomosis and bilateral presence of sperm in the vas fluid during vasovasostomy. Results of end-to-end and side-to-side macrosurgical anastomosis, as well as of 1-layer and 2-layer microsurgical anastomosis were similar. Macrosurgical success rates were 84 per cent for patency and 35 per cent for pregnancy in the 300 cases. Microsurgical success rates were 90 per cent for patency and 51 per cent for pregnancy in 324 cases. Failure of patency was caused mainly by anastomotic scar formation with sperm and suture granulomas. Failure of pregnancy was owing mainly to inadequate postoperative semen quality.

Cloning, chromosomal localization, and tissue expression of autotaxin from human teratocarcinoma cells

Autotaxin, a potent human tumor cell motility-stimulating exophosphodiesterase, was isolated and cloned from the human teratocarcinoma cell line NTera2D1. The deduced amino acid sequence for the teratocarcinoma autotaxin has 94% identity to the melanoma-derived protein, 90% identity to rat brain phosphodiesterase I/nucleotide pyrophosphatase (PD-I alpha), and 44% identity to the plasma cell membrane marker PC-I. Utilizing polymerase chain reaction screening of the CEPH YAC library, we localized the autotaxin gene to human chromosome 8q23-24. Northern blot analysis of relative mRNA from multiple human tissues revealed that autotaxin mRNA steady state expression is most abundant in brain, placenta, ovary, and small intestine.

Photoinactivation of photosystem II complexes and photoprotection by non-functional neighbours in Capsicum annuum L. leaves

Leaf segments from Capsicum annuum plants grown at 100 micromol photons m(-2) s(-1) (low light) or 500 micromol photons m(-2) s(-1) (high light) were illuminated at three irradiances and three temperatures for several hours. At various times, the remaining fraction (f) of functional photosystem II (PS II) complexes was measured by a chlorophyll fluorescence parameter (1/Fo -1/Fm, where Fo and Fm are the fluorescence yields corresponding to open and closed PS II traps, respectively), which was in turn calibrated by the oxygen yield per saturating single-turnover flash. During illumination of leaf segments in the presence of lincomycin, an inhibitor of chloroplast-encoded protein synthesis, the decline of f from 1.0 to about 0.3 was mono-exponential. Thereafter, f declined much more slowly, the remaining fraction (approximately equals 0.2) being able to survive prolonged illumination. The results can be interpreted as being in support of the hypothesis that photoinactivated PS II complexes photoprotect functional neighbours (G. Oquist et al. 1992, Planta 186: 450-460), provided it is assumed that a photoinactivated PS II is initially only a weak quencher of excitation energy, but becomes a much stronger quencher during prolonged illumination when a substantial fraction of PS II complexes has also been photoinactivated. In the absence of lincomycin, photoinactivation and repair of PS II occur in parallel, allowing f to reach a steady-state value that is determined by the treatment irradiance, temperature and growth irradiance. The results obtained in the presence and absence of lincomycin are analysed according to a simple kinetic model which formally incorporates a conversion from weak to strong quenchers, yielding the rate coefficients of photoinactivation and of repair for various conditions, as well as gaining an insight into the influence off on the rate coefficient of photoinactivation. They demonstrate that the method is a convenient alternative to the use of radiolabelled amino acids for quantifying photoinactivation and repair of PS II in leaves.

N-terminal fatty-acylation of sonic hedgehog enhances the induction of rodent ventral forebrain neurons

The adult basal ganglia arise from the medial and lateral ganglionic eminences, morphologically distinct structures found in the embryonic telencephalon. We have previously shown that temporal changes in sonic hedgehog (Shh) responsiveness determine the sequential induction of embryonic neurons that populate the medial and lateral ganglionic eminences. In this report, we show that Shh-mediated differentiation of neurons that populate the lateral ganglionic eminence express different combinations of the homeobox-containing transcription factors Dlx, Mash1 and Islet 1/2. Furthermore, we show that N-terminal fatty-acylation of Shh significantly enhances its ability to induce the differentiation of rat E11 telencephalic neurons expressing Dlx, Islet 1/2 or Mash1. Recent evidence indicates that in utero injection of the E9.5 mouse forebrain with retroviruses encoding wild-type Shh induces the ectopic expression of Dlx2 and severe deformities in the brain. In this report, we show that Shh containing a mutation at the site of acylation prevents either of these phenotypes. These results suggest that N-terminal fatty-acylation of Shh may play an important role in Shh-dependent signaling during rodent ventral forebrain formation.

The role of intravenous immunoglobulin in toxic epidermal necrolysis: a retrospective analysis of 64 patients managed in a specialized centre

BACKGROUND

Toxic epidermal necrolysis (TEN) is a severe cutaneous adverse drug reaction with a mortality of 40%. Intravenous immunoglobulin (IVIg) is widely used as a specific treatment for this reaction, although evidence of its benefit is conflicting.

OBJECTIVES

We sought to evaluate whether the use of IVIg improved mortality in patients with Stevens-Johnson syndrome (SJS)/TEN overlap and TEN.

METHODS

We retrospectively analysed data for 64 patients with SJS/TEN overlap and TEN who were treated with IVIg at a single referral centre. The primary outcome analysed was in-hospital mortality. Predicted mortality was calculated based on severity-of-illness score for TEN (SCORTEN) values. Secondary analyses of survival based on IVIg dosages and prior corticosteroid exposure were also performed.

RESULTS

There were 28 cases of SJS/TEN overlap and 36 cases of TEN, with a mean SCORTEN value of 2·6. The mean dose of IVIg given was 2·4 g kg(-1) and the mean delay from the onset of epidermal detachment to administration of IVIg was 3·2 days. There were 20 deaths (31%) in our cohort. The standardized mortality rate was 1·10 (95% confidence interval 0·62-1·58). Subgroup analysis comparing survivors and nonsurvivors showed a higher SCORTEN in nonsurvivors (3·4 vs. 2·2). There were no differences with regard to the dosage, delay and duration of IVIg administration. When stratified according to dosage, there was no mortality difference between patients who receive high-dose (≥ 3 g kg(-1) ) vs. low-dose (< 3 g kg(-1) ) IVIg.

CONCLUSIONS

This study shows that the use of IVIg does not yield survival benefits in SJS/TEN overlap and TEN, even when corrected for IVIg dosages.