Urinary trans,trans-muconic acid determined by liquid chromatography: application in biological monitoring of benzene exposure

We describe a sensitive and specific high-performance liquid-chromatographic method for determining the benzene metabolite, trans,trans-muconic acid (ttMA) in urine by measuring ultraviolet absorbance at 265 nm. We mix 1 mL of urine sample with 2 mL of Tris buffer containing vanillic acid as internal standard (IS) and percolate this through a preconditioned ion-exchange column. After rinsing the column with phosphoric acid solution, acetate buffer, and deionized water, we elute the analytes with 2 mL of an equivolume solution of 1.5 mol/L sodium chloride and methanol. Of this, 5 microL is injected into the HPLC column. The mobile phase used consists of, per liter, 10 mL of acetic acid, 100 mL of methanol, and the rest 5 mmol/L sodium acetate. The flow rate was started at 1 mL/min and increased to 1.5 mL/min after 6 min. ttMA and IS were detected at 5.2 and 10.2 min, respectively. The lowest detection limit is 125 pg. Analytical recovery and reproducibility generally exceeded 90%. We validated the method with urine samples collected from normal persons and from refinery workers exposed to benzene concentrations < 1 microL/L. The results show that urinary ttMA is a promising biological marker for risk assessment of low-concentration benzene exposure.

Evolutionarily Conserved Sequence Features Regulate the Formation of the FG Network at the Center of the Nuclear Pore Complex

The nuclear pore complex (NPC) is the portal for bidirectional transportation of cargos between the nucleus and the cytoplasm. While most of the structural elements of the NPC, i.e. nucleoporins (Nups), are well characterized, the exact transport mechanism is still under much debate. Many of the functional Nups are rich in phenylalanine-glycine (FG) repeats and are believed to play the key role in nucleocytoplasmic transport. We present a bioinformatics study conducted on more than a thousand FG Nups across 252 species. Our results reveal the regulatory role of polar residues and specific sequences of charged residues, named 'like charge regions' (LCRs), in the formation of the FG network at the center of the NPC. Positively charged LCRs prepare the environment for negatively charged cargo complexes and regulate the size of the FG network. The low number density of charged residues in these regions prevents FG domains from forming a relaxed coil structure. Our results highlight the significant role of polar interactions in FG network formation at the center of the NPC and demonstrate that the specific localization of LCRs, FG motifs, charged, and polar residues regulate the formation of the FG network at the center of the NPC.

MET in gastric carcinomas: comparison between protein expression and gene copy number and impact on clinical outcome

Background:

The aim of this study was to compare gene copy number (GCN) and protein expression of MET and to evaluate their prognostic roles in gastric carcinomas.

Methods:

MET protein expression and gene amplification (GA) status were determined by immunohistochemistry (IHC) and silver in-situ hybridisation (SISH), respectively, in a large series of gastric carcinoma.

Results:

Protein overexpression was observed in 104 of 438 cases, with IHC 2+ in 94 and IHC 3+ in 10, and high polysomy of chromosome 7 and GA were found in 61 and 13 of 381, respectively. Direct comparison revealed a significant correlation between high level of protein expression and increased GCN. All cases with GA showed protein overexpression. Furthermore, all with IHC 3+ showed GA except 1, even which could be categorised as GA according to the ASCO/CAP guideline for human epidermal growth factor receptor 2 assessment. IHC 3+ and GA were significantly associated with poor prognosis.

Conclusion:

MET IHC reflects well on GA, and therefore, it could be a primary screening test for patient selection for anti-MET therapy if GA is a major determinant of drug responsiveness. Also, the prognostic role of MET indicates that anti-MET therapy is a very promising modality in adjuvant treatment for gastric cancer.

A hypoxia-dependent upregulation of hypoxia-inducible factor-1 by nuclear factor-κB promotes gastric tumour growth and angiogenesis

BACKGROUND

The underlying mechanisms involved in the activation of hypoxia-inducible factor-1 (HIF-1) in gastric cancer remain unclear. As nuclear factor-κB (NF-κB) as well as HIF-1 have been implicated in angiogenesis of various cancers, we investigated their relationship in gastric cancer.

METHODS

Nuclear expressions of HIF-1α and NF-κB/RelA were assessed in 251 human gastric carcinoma specimens by immunohistochemical tissue array analysis. Stable human gastric cancer cells, infected with a retroviral vector containing super-suppressive mutant form of IκBα (IκBαM), were used for animal studies as well as cell culture experiments. Xenografted tumours were measured and IκBαM effects on angiogenesis and HIF-1α activation were assessed by immunohistochemistry, western blotting, luciferase reporter assay, and semiquantitative reverse transcription-polymerase chain reaction. In addition, NF-κB effects on the HIF-1α degradation and synthesis were examined.

RESULTS

Hypoxia-inducible factor-1α activation positively correlated with RelA activation in clinical gastric cancer samples (P<0.001). The IκBαM overexpression suppressed tumour growth, microvessel density, and HIF-1α activation in xenografted tumours. Cell culture experiments showed that hypoxia-induced HIF-1α expression was reduced by NF-κB inhibition under hypoxic conditions at the translational level.

CONCLUSION

The hypoxia-dependent activation of the NF-κB/HIF-1α/VEGF pathway contributes, at least in part, to gastric cancer promotion via enhancement of angiogenesis.

PTEN status switches cell fate between premature senescence and apoptosis in glioma exposed to ionizing radiation

Loss of the tumor suppressor phosphatase and tensin homolog (PTEN) has frequently been observed in human gliomas, conferring AKT activation and resistance to ionizing radiation (IR) and drug treatments. Recent reports have shown that PTEN loss or AKT activation induces premature senescence, but many details regarding this effect remain obscure. In this study, we tested whether the status of PTEN determined fate of the cell by examining PTEN-deficient U87, U251, and U373, and PTEN-proficient LN18 and LN428 glioma cells after exposure to IR. These cells exhibited different cellular responses, senescence or apoptosis, depending on the PTEN status. We further observed that PTEN-deficient U87 cells with high levels of both AKT activation and intracellular reactive oxygen species (ROS) underwent senescence, whereas PTEN-proficient LN18 cells entered apoptosis. ROS were indispensable for inducing senescence in PTEN-deficient cells, but not for apoptosis in PTEN-proficient cells. Furthermore, transfection with wild-type (wt) PTEN or AKT small interfering RNA induced a change from premature senescence to apoptosis and depletion of p53 or p21 prevented IR-induced premature senescence in U87 cells. Our data indicate that PTEN acts as a pivotal determinant of cell fate, regarding senescence and apoptosis in IR-exposed glioma cells. We conclude that premature senescence could have a compensatory role for apoptosis in the absence of the tumor suppressor PTEN through the AKT/ROS/p53/p21 signaling pathway.

Prognostic implications of type and density of tumour-infiltrating lymphocytes in gastric cancer

The study aims to determine whether type and density of tumour-infiltrating lymphocytes (TILs) can predict the clinical course in gastric cancer. Gastric carcinomas (n=220) were immunostained for CD3, CD8, CD20, and CD45RO and evaluated for clinicopathologic characteristics. Number of TILs that immunostained positively for each marker were counted using NIH ImageJ software. Tumours were grouped into low- and high-density groups for each marker (CD3, CD8, CD45RO). The densities of CD3(+), CD8(+), and CD45RO(+) TILs were found to be independent predictors of lymph node metastasis by multivariate analysis with odds ratios (95% CI) of 0.425 (0.204-0.885), 0.325 (0.150-0.707), and 0.402 (0.190-0.850), respectively. Kaplan-Meier survival analysis revealed that patients in the high-density groups for CD3, CD8, and C45RO had a significantly longer survival time than the patients in the corresponding low-density groups, respectively. In multivariate survival analysis, the densities of CD3(+), CD8(+), and CD45RO(+) TILs remained independent prognostic factors with hazard ratios (95% CI) of 0.549 (0.317-0.951), 0.574 (0.347-0.949), and 0.507 (0.298-0.862), respectively. In conclusion, density of TILs was found to be independently predictive of regional lymph node metastasis and patient survival in gastric cancer.

Characteristics of KIT-negative gastrointestinal stromal tumours and diagnostic utility of protein kinase C theta immunostaining

AIMS

To characterise KIT-negative gastrointestinal stromal tumours (GISTs) clinically, pathologically, immunohistochemically and genetically, and to establish the usefulness of protein kinase C theta (PKC) as a diagnostic marker in KIT-negative GIST.

METHODS

252 consecutive cases of GIST were evaluated for clinicopathological characteristics and immunostained for various antibodies. Mutational analyses of KIT and platelet-derived growth factor receptor alpha (PDGFRA) were also performed in 62 cases.

RESULTS

20 (7.9%) GISTs showed negative immunostaining for KIT. KIT-negative GISTs were more likely to originate from omentum or peritoneum, have an epithelioid histology, and be classified as high risk. The overall survival rate of patients with KIT-negative GISTs (5-year survival rate 68.7% (SD 10.7%)) was lower than that of patients with KIT-positive GISTs (5-year survival rate, 79.9% (3.0%)) (p = 0.042, log-rank test). Negative KIT expression was an independent prognostic factor in multivariate Cox regression analysis when the risk of aggressive behaviour and the status of imatinib treatment were adopted as covariates. KIT-negative GISTs also showed lower expression rates of CD34, Bcl-2, and PKC than KIT-positive GISTs; mutational analysis revealed that 30% of KIT-negative GISTs harboured a PDGFRA exon 18 mutation. Immunostaining on PKC showed that 93.9% of all GISTs expressed PKC protein. However, 21.9% of 64 mesenchymal tumours other than GIST also showed positivity on PKC.

CONCLUSIONS

KIT-negative GISTs had characteristics that differ from those of KIT-positive GISTs, and negative KIT expression was an independent prognostic indicator for overall survival of patients. Although PKC is a sensitive diagnostic marker for GIST, its usefulness is limited because of low sensitivity and low specificity in KIT-negative GISTs.

Oxidative burden in prediabetic and diabetic individuals: evidence from plasma coenzyme Q(10)

AIM

Individuals with diabetes and prediabetes are at risk of vascular injury. However, the exact mechanisms are unclear. The mitochondria mobile electron carrier coenzyme Q(10) (CoQ(10)) is a potent lipophilic antioxidant. We hypothesize that oxidative stress, detectable as changes in plasma CoQ(10) concentrations and composition, plays an important role in vascular disease in diabetes.

METHODS

We measured plasma CoQ(10) concentrations (including reduced ubiquinol and oxidized ubiquinone subfractions) in 60 subjects with normal glucose tolerance [NGT; fasting plasma glucose (FPG) < 5.5 mmol/l], 63 with impaired fasting glucose (IFG; FPG 5.6-6.9 mmol/l) and 69 with Type 2 diabetes (DM; FPG > 6.9 mmol/l).

RESULTS

In men and women, the total CoQ(10)/total cholesterol ratio was reduced in DM (mean +/-sd) [male (M) 0.09 +/- 0.04; female (F) 0.07 +/- 0.04] compared with NGT (0.29 +/- 0.08; 0.21 +/- 0.07) and IFG (0.27 +/- 0.07; 0.23 +/- 0.07) (DM vs. NGT and IFG P = 0.001). A stepwise reduction in the plasma ubiquinol fraction (ubiquinol/total CoQ10) was observed from NGT (M 0.93 +/- 0.06; F 0.95 +/- 0.06) compared with IFG (0.43 +/- 0.25; 0.41 +/- 0.15) and DM (0.24 +/- 0.11; F 0.29 +/- 0.16) (DM vs. IFG vs. NGT P = 0.001). In contrast, the plasma ubiquinone/ubiquinol ratio increased from NGT (M 0.08 +/- 0.07, F 0.06 +/- 0.08) to IFG (2.14 +/- 1.84, 1.75 +/- 1.04) to DM (4.77 +/- 4.88, 3.81 +/- 3.71) (DM vs. IFG vs. NGT P = 0.001). These differences remained after adjusting for age, body mass index and FPG.

CONCLUSIONS

The change in CoQ(10) with increasing FPG concentration suggests an increase in oxidative burden, already evident in the prediabetic IFG individuals. This increase in oxidative stress might contribute to the increased risk of vascular disease.

The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724

Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness--the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

The afterglow of GRB 050709 and the nature of the short-hard gamma-ray bursts

The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.

Human selenoproteins at a glance

The public perception of selenium has changed significantly over the last decades. Originally mainly known for its high toxicity, it was later recognized as an essential trace element and is now (despite its narrow therapeutic window) almost being marketed as a lifestyle drug. Indeed, some clinical and preclinical studies suggest that selenium supplementation may be beneficial in a large number of clinical conditions. However, its mode of action is unresolved in most of these cases. Selenocysteine - identified as the 21st amino acid used in ribosome-mediated protein synthesis - is incorporated in at least 25 specific, genetically determined human selenoproteins, many of which have only recently been discovered. Restoration of normal selenoprotein levels may be - apart from direct supranutritional effects - one possible explanation for the effects of selenium supplements. In this review we provide a brief but up-to-date overview of what is currently known about these 25 acknowledged human selenoproteins and their synthesis.

Fatigue of Cord-Rubber Composites: V. Cord Reinforcement Effect

Fatigue behavior of cord-rubber composite materials forming the belt region of radial pneumatic tires has been characterized to assess their dependence on stress, strain and temperature history as well as materials composition and construction. Estimated at various levels of stress amplitude were the fatigue life, the extent and rate of resultant strain increase (“dynamic creep”), cyclic strains at failure, and specimen temperature. Reflecting their matrix-dominated failure modes, such as cord-matrix debonding and delamination, composite laminates with different cord reinforcements showed the same S-N relationship as long as they were constructed with the same rubber matrix, the same cord angle, similar cord volume, and the same ply lay-up. The interply shear strain of 2-ply ‘tire belt’ composite laminate under circumferential tension was affected by twisting of specimen due to tension-bending coupling. However, a critical level of interply shear strain, which governs the gross failure of composite laminate due to the delamination, appeared to be independent of different lay-up of 2-ply vs symmetric 4-ply configuration. Because of much lower values of single cycle strength (in terms of gross fracture load per unit width), the composite laminates with larger cord angle and the 2-ply laminates exhibited exponentially shorter fatigue lifetime, at a given stress amplitude, than the composite laminates with smaller cord angle and 4-ply symmetric laminates, respectively. Maximum cyclic strain of composite laminates at failure, which measures the total strain accumulation for gross failure, was independent of stress amplitude and close to the level of static failure strain. For all composite laminates under study, a linear correlation could be established between the temperature rise rate and dynamic creep rate which was, in turn, inversely proportional to the fatigue lifetime.

Calreticulin enriched as an early-stage encapsulation protein in wax moth Galleria mellonella larvae

To investigate the molecular mechanism of the early-stage encapsulation reaction in insects, we purified a 47kDa protein from injected beads into Galleria mellonella larvae. When a cDNA clone was isolated, the 47kDa protein showed high homology with Drosophila and human calreticulin. Western blotting analysis showed that the 47kDa protein was present in the hemocytes, but not in the plasma. When the early-stage encapsulated beads were coated with 47kDa protein antibody and reinjected into G. mellonella larvae, any further encapsulation reaction was inhibited. These results suggest that calreticulin is involved in non-self recognition in invertebrate cellular defense reactions.

Assessment of markers for the identification of microsatellite instability phenotype in gastric neoplasms

We tested three mononucleotide, 45 dinucleotide, and five tetranucleotide repeats in 30 gastric adenomas and 30 gastric carcinomas for microsatellite instability (MSI) in order to evaluate which microsatellites might indicate the MSI status in gastric neoplasms. Along with the increase in tested markers, the proportion of low-frequency MSI (MSI-L) tumors increased. On immunohistochemistry, MSI-L gastric neoplasms did not show any alteration in hMLH1 or hMSH2 protein expression, while most of the high-frequency MSI (MSI-H) tumors did show alterations in the above mismatch repair proteins. The above findings suggested that MSI-L tumors cannot be distinguished from microsatellite stable tumors. Two mononucleotides, BAT25 and BAT26, were sufficient for the screening of MSI. An additional three dinucleotides, D17S786, D6S105 and D19S188, were also highly sensitive and specific in identifying MSI phenotype tumors.

Microsatellite instability in synchronous gastric carcinomas

Synchronous gastric carcinomas are found in 4% to 10% of all gastric carcinomas, and the tumor multiplicity is believed to be related to genetic predisposition. To investigate the role of mismatch repair error in synchronous gastric carcinomas, we analyzed the microsatellite instability (MSI) status of 101 cancers from 48 gastrectomy specimens and compared them with 149 solitary gastric carcinomas. Multiple synchronous gastric carcinomas are characterized by slightly older age, predominance in males, early stage and lower lymph node metastasis. Among the 48 cases, 8 (18 lesions) were associated with a gastric adenoma (type I) and 40 (83 lesions) were not associated with a gastric adenoma (type II). The MSI+ rate was 50% in the type I and 8.4% in the type II synchronous gastric carcinomas (p < 0.001), while that of solitary gastric carcinomas was 9.4%. In addition, the frameshift mutation rates of the TGF-betaRII, BAX and hMSH3 genes in the type I synchronous carcinomas were higher than those in the type II synchronous carcinomas. These findings indicate that a defect in the mismatch repair system might play a role in the carcinogenesis of a minor subset of multiple gastric carcinomas associated with adenomas.

Reconstituted basement membrane induces glandular-like morphogenesis but no difference in ACTH synthesis of anterior pituitary cells

Basement membrane, a thin extracellular matrix, promotes tissue integrity and differentiated phenotype. This study was performed in order to investigate the effect of basement membrane components on adrenocorticotropin (ACTH) synthesis and to observe its relationship with cell morphology. Rat anterior pituitary cells were cultured on plastic culture plate coated with either Matrigel or poly-D-lysine. Phase-contrast microscopy and scanning electron microscopy showed that cells cultured on Matrigel appeared as a three-dimensional glandular-like cell aggregate, while those cultured on plastic showed a flat, confluent monolayer. Reverse-transcription polymerase chain reaction (RT-PCR) and Northern blot analysis revealed that ACTH synthesis in the Matrigel culture was not significantly different from that in the plastic culture. Our results suggest that the relationship between the morphological changes caused by cell-substrate interaction and pituitary hormone synthesis does not exist in all pituitary cell types and that other factors associated with cell-substrate interaction influence the hormone synthesis of some pituitary cells.

Effect of c-Abl tyrosine kinase on the cellular response to paclitaxel-induced microtubule damage

DNA damage has been shown to activate c-Abl tyrosine kinase. We now report that, in addition to DNA damage, microtubule damage induced by paclitaxel results in activation of c-Abl kinase. In 3T3 cells, the presence of c-Abl kinase increased paclitaxel-induced cell death. In Abl-proficient cells, paclitaxel produced a marked and prolonged G2/M arrest which peaked at 24 h and a rapid and marked induction of p21(WAF1)which also peaked at 24 h. In Abl-deficient cells, the G2/M arrest induced by paclitaxel was less prominent and shorter in duration and the effect of paclitaxel on p21(WAF1)expression was reduced and delayed. Paclitaxel had no effect on p53 expression and MAPK phosphorylation. These findings indicate that, in 3T3 cells, c-Abl kinase facilitates cell death and regulates G2/M arrest in response to paclitaxel-induced microtubule damage in a pathway that is dependent on p21(WAF1)and independent of MAPK activity.

A masquerade-like serine proteinase homologue is necessary for phenoloxidase activity in the coleopteran insect, Holotrichia diomphalia larvae

Previously, we reported the molecular cloning of cDNA for the prophenoloxidase activating factor-I (PPAF-I) that encoded a member of the serine proteinase group with a disulfide-knotted motif at the N-terminus and a trypsin-like catalytic domain at the C-terminus [Lee, S.Y., Cho, M.Y., Hyun, J.H., Lee, K.M., Homma, K.I., Natori, S. , Kawabata, S.I., Iwanaga, S. & Lee, B.L. (1998) Eur. J. Biochem. 257, 615-621]. PPAF-I is directly involved in the activation of pro-phenoloxidase (pro-PO) by limited proteolysis and the overall structure is highly similar to that of Drosophila easter serine protease, an essential serine protease zymogen for pattern formation in normal embryonic development. Here, we report purification and molecular cloning of cDNA for another 45-kDa novel PPAF from the hemocyte lysate of Holotrichia diomphalia larvae. The gene encodes a serine proteinase homologue consisting of 415 amino-acid residues with a molecular mass of 45 256 Da. The overall structure of the 45-kDa protein is similar to that of masquerade, a serine proteinase homologue expressed during embryogenesis, larval, and pupal development in Drosophila melanogaster. The 45-kDa protein contained a trypsin-like serine proteinase domain at the C-terminus, except for the substitution of Ser of the active site triad to Gly and had a disulfide-knotted domain at the N-terminus. A highly similar 45-kDa serine proteinase homologue was also cloned from the larval cDNA library of another coleopteran, Tenebrio molitor. By in vitro reconstitution experiments, we found that the purified 45-kDa serine proteinase homologue, the purified active PPAF-I and the purified pro-PO were necessary for expressing phenoloxidase activity in the Holotrichia pro-PO system. However, incubation of pro-PO with either PPAF-I or 45-kDa protein, no phenoloxidase activity was observed. Interestingly, when the 45-kDa protein was incubated with PPAF-I and pro-PO in the absence, but not in the presence of Ca2+, the 45-kDa protein was cleaved to a 35-kDa protein. RNA blot hybridization revealed that expression of the 45-kDa protein was increased in the Holotrichia hemolymph after Escherichia coli challenge.

Comparative analysis of tea catechins and theaflavins by high-performance liquid chromatography and capillary electrophoresis

This paper describes the simultaneous determination of catechins and theaflavins in green and black teas, using reversed-phase high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). The tea polyphenols analyzed included (+)-catechin, catechin gallate, (-)-epicatechin, epicatechin-3-gallate, epigallocatechin, epigallocatechin-3-gallate, theaflavin, theaflavin-3-monogallate, theaflavin-3'-monogallate and theaflavin-3,3'-gallate. These polyphenols together with six other tea ingredients such as caffeine, adenine, theophylline, quercetin, gallic acid and caffeic acid were separated within 27 min by HPLC and in less than 10 min by CE. The optimal analytical conditions of both chromatographic methods were investigated for the convenience and reliability for routine analysis. Both HPLC and CE were found to be reliable and compatible. The reproducibility of the within-day assay using both methods was generally >90%. The day-to-day variation of retention time was <5% for HPLC, while the variation of migration time for CE was <2%. The analysis time of CE was three-times faster, however it is five-times less sensitive than HPLC, which has detection limits of 0.05 microg/ml and 0.5 microg/ml for catechins and theaflavins, respectively.

Activated phenoloxidase from Tenebrio molitor larvae enhances the synthesis of melanin by using a vitellogenin-like protein in the presence of dopamine

One of the biological functions of activated phenoloxidase in arthropods is the synthesis of melanin around invaded foreign materials. However, little is known about how activated phenoloxidase synthesizes melanin at the molecular level. Even though it has been suggested that the quinone derivatives generated by activated phenoloxidase might use endogenous protein components for melanin synthesis in arthropods, there is no report of protein components engaged in melanin synthesis induced by activated phenoloxidase. In this study, to isolate and characterize proteins involved in melanin synthesis, we prepared in vitro prophenoloxidase activating solution (designated G-100 solution), specifically showing phenoloxidase activity in the presence of Ca2+ and beta-1, 3-glucan, from the hemolymph of larvae of the coleopteran Tenebrio molitor by using a Sephadex G-100 column. When G-100 solution was incubated with dopamine to induce melanin synthesis in the presence of Ca2+ and beta-1,3-glucan, four types of protein (160 kDa, prophenoloxidase, phenoloxidase and 45 kDa) disappeared from SDS/PAGE under reducing conditions. Under identical conditions, but including phenylthiourea as a phenoloxidase inhibitor added to the G-100 solution, three of these proteins (160 kDa, phenoloxidase and 45 kDa) did not disappear. To characterize these melanization-engaging proteins, we first purified the 160-kDa melanization-engaging protein to homogeneity and raised a polyclonal antibody against it. Analysis of the cDNA revealed that it consisted of 1439 amino-acid residues and showed partial homology with Caenorhabditis elegans vitellogenin precursor-6 (19.7%). Western blot analysis showed that it disappeared when active phenoloxidase induced melanin synthesis. Furthermore, when the purified 160-kDa melanization-engaging protein was added to a G-100 solution deficient in it, melanin synthesis was enhanced compared with the same solution without the protein. These data support the conclusion that the 160-kDa vitellogenin-like protein is involved in arthropod melanin synthesis.

Caloric restriction prevents oxidative damage induced by the carcinogen clofibrate in mouse liver

Long-term caloric restriction in rodents is known to decrease levels of oxidative damage, which may contribute to an 'anti-ageing' effect. We show here that a shorter period (10 months) of caloric restriction had only small effects on levels of oxidative DNA and protein damage in the livers of mice, but completely attenuated increased oxidative damage caused by the carcinogen clofibrate. Since clofibrate is thought to exert its actions by increasing oxidative damage, our data suggest that 10 months of caloric restriction can increase the resistance of tissues to agents inducing oxidative stress. This may be an important factor in explaining how caloric restriction decreases cancer incidence.

Bacterial-injection-induced syntheses of N-beta-alanyldopamine and Dopa decarboxylase in the hemolymph of coleopteran insect, Tenebrio molitor larvae

Injection of Escherichia coli into larvae of the coleopteran Tenebrio molitor resulted in the appearance of a dopamine-like substance on the electrochemical detector. To characterize this dopamine-like substance, we purified it to homogeneity from the immunized hemolymph and determined its molecular structure to be N-beta-alanyldopamine using the liquid chromatographic/tandem mass spectrometric method. Chemically synthesized N-beta-alanyldopamine showed the same retention time on HPLC as the purified N-beta-alanyldopamine from immunized larvae. To elucidate the molecular mechanism of N-beta-alanyldopamine synthesis in vivo, we examined the enzyme activity of Dopa decarboxylase against E. coli-injected hemolymph of T. molitor larvae. The enzyme activity of Dopa decarboxylase increased dramatically approximately 8 h after injection; Dopa decarboxylase activity of injected larvae being 10-times higher than naive larvae after 24 h. To evaluate the extent of quantitative changes of Dopa decarboxylase in response to bacterial challenge, Tenebrio Dopa decarboxylase was purified to homogeneity from the whole larvae and a cDNA clone for Tenebrio Dopa decarboxylase was isolated. RNA blot hybridization revealed that expression of the Dopa decarboxylase gene was activated transiently 3-8 h after E. coli challenge. Immunoprecipitation experiments showed that Tenebrio Dopa decarboxylase was detected from 8 to 24 h in E. coli-injected larval extract. Thus, bacterial injection into T. molitor larvae might induce transcriptional activation of a Dopa decarboxylase gene, and then synthesis of N-beta-alanyldopamine. The synthesized N-beta-alanyldopamine might be used as a substrate by phenoloxidase during melanin synthesis in the humoral defense response or the melanotic encapsulation reaction of the cellular defense response.

Role of reconstituted basement membrane in human granulosa cell culture

The effects of Matrigel, a reconstituted basement membrane, on human granulosa cells were investigated. Cells were obtained from follicular aspirate in the course of oocyte retrieval for in vitro fertilization and were cultured on either a surface coated with Matrigel or uncoated plastic. Light and electron microscopy showed that granulosa cells cultured on Matrigel demonstrated three-dimensional aggregated cells with well differentiated morphology: numerous lipid droplets, microvilli, junctional complexes and lumen-like structures were seen. In contrast, cells cultured on plastic were flattened, poorly differentiated and showed apoptotic cells. Immunocytochemistry showed that the proportion of immunopositive cells for 3beta-hydroxysteroid dehydrogenase was increased in cultures on Matrigel. The results of the present study suggest that culture on Matrigel promotes the differentiation of human granulosa cells and provides a useful tool which may improve the efficiency of in vitro fertilization.

Health-related quality of life in patients with cataract and glaucoma

The patient's perspective of his or her own health status as it relates to functioning and well-being is referred to as health-related quality of life. Various generic and ophthalmology-specific survey instruments have been used to gain an understanding of patient-oriented health status in patients with cataract or with glaucoma. Improvement in vision-targeted quality of life has been shown following cataract surgery; however, an improvement in self-perceived overall health status following cataract surgery has not been established. Increasing severity of glaucoma has been shown to be negatively related to vision-targeted quality of life; the relationship between increasing severity of glaucoma and overall self-perceived health status is inconclusive. Integration of the concepts of health-related quality of life into clinical practice will require the development of better measurement instruments that can demonstrate notable outcome advantages for patients.

Effect of Salvia miltiorrhiza on aflatoxin B1-induced oxidative stress in cultured rat hepatocytes

Recent findings have suggested that oxidative damage might contribute to the cytotoxicity and carcinogenicity of aflatoxin B1 (AFB1). Salvia miltiorrhiza (Sm), a herbal plant that has been used extensively in traditional Chinese medicine for treating cardiovascular and liver diseases, is believed to have some antioxidative capabilities. In this study, the protective effect of Sm against AFB1-induced cytotoxicity was investigated in cultured primary rat hepatocytes. AFB1-induced cytotoxicity and lipid peroxidation (LPO) were estimated by determination of lactate dehydrogenase (LDH) leakage and thiobarbituric acid reactive substances (TBARS) formation, respectively. Intracellular reactive oxygen species (ROS) formation was measured using a fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA). In addition, changes of intracellular glutathione (GSH) content were also studied. Results showed that Sm was able to suppress the LDH leakage induced by AFB1 in a dose-dependent manner. A dose-dependent inhibitory effect of Sm on AFB1-induced LPO was also found in hepatocytes treated with Sm. It was further observed that Sm produced an inhibitory effect on ROS formation caused by AFB1. Concomitantly, the GSH content in Sm-treated groups increased substantially compared to those without Sm treatment. These findings suggest that Sm can inhibit the cytotoxicity of AFB1 through decreasing ROS formation, inhibiting LPO and preventing GSH depletion. The major component of the aqueous extract of Sm was identified by using high performance liquid chromatography (HPLC), proton magnetic resonance (1H-NMR) and mass spectrum (MS). Analytical results suggested that D(+)beta3,4-dihydroxyphenol lactic acid (DA) is the main compound of the aqueous extract of Sm.

Entoptic foveal avascular zone measurement and diabetic retinopathy

BACKGROUND

Entoptic visualization of the foveal avascular zone (FAZ) provides a noninvasive method for measurement of the FAZ. To determine if repeatability of measurement with this technique is good enough to monitor changes in diabetic retinopathy, we quantify (1) the repeatability of entoptic FAZ measurement in healthy subjects and (2) the relationship between measured FAZ diameter and the severity of retinopathy.

METHODS

(1) To determine FAZ measurement repeatability, 10 healthy adults entoptically measured their FAZ diameters in 11 separate testing sessions. (2) In a separate experiment, 53 patients with varying levels of diabetic retinopathy and 21 control subjects used a vascular entoptoscope to measure their FAZ diameters.

RESULTS

The disease-related increase in FAZ diameter is large (approximately 400 microm) compared to the repeatability of the entoptic measurement within a subject (SD approximately 35 microm).

CONCLUSION

Entoptic measurements have the repeatability necessary to reliably monitor increases in FAZ diameter of the magnitude of those induced by diabetes.

Induction of c-Jun mRNA without changes of estrogen and progesterone receptor expression in myometrium during human labor

To elucidate the endocrine mechanism of human parturition, the expression of c-Jun and c-Fos mRNA were examined in relation to estrogen receptor (ER) and progesterone receptor (PR) in human myometrium. c-Jun mRNA was detected in all myometrial tissues (n=5) during labor but not before labor (n=5) and in oxytocin-resistant postterm pregnancy (n=3). c-Fos mRNA was detected in only one myometrial tissue from a woman in labor. The distribution and intensity of immunostaining for ER and PR were semiquantitatively scored. During the late pregnancies, no significant difference was seen in the receptor scores for myometrial ER and PR between the patients who experienced labor and those who did not. Receptor scores for ER and PR were significantly lower in postterm pregnancy than in late pregnancy, regardless of the labor status. These data suggest that there are no changes in ER and PR in human myometrium during parturition. On the other hand, postterm pregnancy is associated with low ER and PR. c-Jun, induced during labor without changes in ER and PR, may play a role as a signaling mechanism in human myometrium.

Elevation of human intraocular pressure at night under moderate illumination

PURPOSE

An endogenous elevation of intraocular pressure (IOP) occurs at night in healthy young adults. The authors studied whether or not this IOP elevation can be detected under moderate illumination.

METHODS

Twenty-five healthy volunteers, ages 18 to 25 years, were housed overnight in a sleep laboratory under a strictly controlled light-dark environment. Intraocular pressure was measured in the supine position every 2 hours, using a pneumatonometer. An 8-hour sleep period was assigned to each volunteer according to individual's accustomed sleep cycle. In the early part of this assigned period, sleep was encouraged with room lights off. Researchers performed IOP measurements at two time points with the aid of night vision goggles. In the middle to the late part of the assigned period, lights were turned on twice for a 1-hour interval. The light intensity was the same as before the bedtime. At the ending of each light period, IOP was measured under illumination.

RESULTS

Average IOP was significantly higher in the assigned sleep period versus outside the period. The trough of mean IOP occurred just before the bedtime, and then IOP gradually increased and peaked at the end of the 8-hour assigned sleep period. The difference between the trough and peak IOP was 3.5 +/- 0.7 mm Hg (mean +/- SEM, n = 25). Within the assigned sleep period, the average IOP determined under illumination was significantly higher than the average IOP preceding the illumination.

CONCLUSIONS

Elevation of IOP occurred during the assigned sleep period with two 1-hour light exposures of moderate intensity. Environmental light at night had no significant effect on the nocturnal IOP elevation in healthy young adults.

A randomized clinical trial of mupirocin in the eradication of Staphylococcus aureus nasal carriage in human immunodeficiency virus disease

Seventy-six human immunodeficiency virus (HIV)-infected patients with Staphylococcus aureus nasal carriage were randomized to treatment groups receiving intranasal mupirocin or placebo twice daily for 5 days. Nasal cultures for S. aureus were obtained at 1, 2, 6, and 10 weeks after therapy. At 1 week, 88% of mupirocin-treated patients had negative nasal cultures compared with 8% in placebo patients (P<.001). The percentage of mupirocin-treated patients with persistently negative nasal cultures decreased over time (63%, 45%, and 29% at 2, 6, and 10 weeks, respectively) but remained significantly greater than the placebo group (3% at 2, 6, and 10 weeks). In mupirocin-treated patients, most (16/19) instances of nasal recolonization were with pretreatment strains (determined by means of by pulsed field gel electrophoresis); mupirocin resistance was not observed. Five days of treatment with mupirocin eliminated S. aureus nasal carriage in HIV-infected patients for several weeks; however, since the effect waned over time, intermittent dosing regimens should be considered for long-term eradication.

Antifungal activities of recombinant antifungal protein by conjugation with polyethylene glycol

Tenecin 3, an antifungal protein isolated from coleopteran insect Tenebrio molitor larvae, inhibited growth of the fungus Candida albicans. We have previously reported that tenecin 3 has a propensity of random structure with very loose turn-like elements by circular dichroism (CD) analysis and 2D nuclear overhauser effect spectroscopy [Lee et al. (1999)]. However, the antifungal mechanism of tenecin-3 has not yet been studied due to its very low availability from natural sources. As an initial step to study the antifungal mechanism of tenecin 3, recombinant tenecin 3 (RT-3) obtained from an expression system in Escherichia coli showed antifungal activity against C. albicans as did natural tenecin 3. To elucidate the antifungal mechanism of RT-3 and to explore the possibility of preparing polyethylene glycol (PEG) conjugated derivative, we synthesized PEG conjugated RT-3 (RT-3-PEG) and examined its antifungal activity against C. albicans in vitro. RT-3-PEG showed greater antifungal activity against C. albicans than RT-3 alone at the same dose. When C. albicans was treated with RT-3-PEG in vitro, K+ in the C. albicans cell was leaked out rapidly compared to the C. albicans treated with RT-3 alone. When the morphological change of RT-3-PEG treated C. albicans was examined by scanning electron microscopy, string-like substances, which may have been derived from the fungus, were stacked around the cell whose wall was damaged. Also, no appreciable hemolysis of mouse erythrocytes was detected under conditions in which 1% melittin caused 100% hemolysis. These results suggested that the RT-3-PEG derivative probably does not interact with mammalian cell appreciably, although it has antifungal activity.

Reconstituted basement membrane reduces proliferation and increases prolactin expression of GH3 cells

This study investigated the effects of reconstituted basement membrane Matrigel on the proliferation and prolactin expression of GH3 cells in culture for 6 days. When cells were cultured on Matrigel, the initial attachment was increased but the cell number was not changed with time whereas rapid increase in cell number was observed in cultures on plastic. Bromodeoxyuridine (BrdU)-labeling showed that BrdU incorporation ratio of GH3 cells cultured on Matrigel was about one half of that observed with cells cultured on plastic (9.7+/-0.7% vs. 18.7+/-1.2%). Immunocytochemistry revealed that the ratio of the prolactin-immunoreactive GH3 cells was about 3.6 times (58.4+/-2.9% on Matrigel vs. 16.2+/-1.4% on plastic), which was compatible with the results of Western blot analysis. In situ hybridization demonstrated that prolactin mRNA-positive cells were identified more frequently when cells were cultured on Matrigel compared to cultures on plastic. These findings indicate that Matrigel is a proper culture substrate for the long-term culture of GH3 pituitary cells due to the inhibition of overgrowth and promotion of prolactin expression.

Laminin-1-adherent cancer cells show increased proliferation and decreased apoptosis in vivo

BACKGROUND

The growth rate of a tumor is dependent on both cell proliferation and cell loss. We have established subpopulations of human colon cancer cells with different in vivo growth rates by selecting the cells according to their adhesiveness to laminin-1 in vitro.

MATERIALS AND METHODS

Laminin-1-adhesion selected colon cancer cells were injected into the cecal wall of nude mice. The tumors were examined 30 days later. Cell proliferation was assessed by proliferating cell nuclear antigen (PCNA) index and apoptotic cells were labeled by digoxigenin-11-dUTP using terminal deoxynucleotidyl transferase.

RESULTS

The laminin-1-adherent cells, which formed larger tumors in vivo, showed increased proliferative activity and reduced apoptosis in comparison with the laminin-1-nonadherent cells.

CONCLUSION

Laminin-1 may enhance the malignant behavior of colon cancer cells by accelerating proliferation as well as by decreasing cell loss.

Development of intracytoplasmic lumens in a colon cancer cell line cultured on a non-adhesive surface

Cell-matrix interactions have important effects on phenotypic features, such as morphology, differentiation and cell growth. Several papers have suggested that when cell-matrix interactions are interrupted, cells grow as multicellular spheroids and eventually undergo apoptosis. We found that when ET(-), a laminin non-adherent colon cancer cell line, was cultured on poly-2-hydroxyethyl methacrylate (HEMA) coated plastic, the cells floated as cellular aggregates of spheroids or as single cells. Some of the single cells contained a very large intracytoplasmic lumen (ICL) and appeared similar to signet ring cells. These ICL were lined by a layer of short microvilli. The number of the cell did not increased cells when cultured on poly-HEMA. Another type of single cells, usually without ICL, demonstrated the characteristics of apoptotic cells by histologic examination. Acridine orange staining, flow cytometry and electron microscopy confirmed the apoptotic nature of those cells. In immunohistochemical staining for proliferating cell nuclear antigen, spheroids of cells and single cells with ICL were immunoreactive, while most of the single cells without ICL were negative. These results suggest that multicellular aggregation and formation of ICL were induced by the adaptation of ET(-) colon cancer cells in a harmful environment caused by reduced adhesiveness, and these changes might be related to cell survival.

Genotoxicity of microcystic cyanobacteria extract of a water source in China

The water pollution of toxic cyanobacteria (blue-green algae) is a worldwide problem and worsens with industrialization. Microcystins are potent cyclic heptapeptidic hepatotoxins produced mainly by Microcystis aeruginosa, and their hepatotoxicity has been well-documented. In contrast, information on the genotoxic effects of microcystins is relatively scarce. In our present study, the genotoxicity of microcystic cyanobacteria extract (MCE) of a water source in China was studied using Salmonella typhimurium assay (Ames test), comet assay (Single cell gel electrophoresis) and mouse micronucleus test. Results from Ames test indicated that MCE had strong mutagenicity regardless of the presence of S9. Moreover, MCE was able to induce DNA damage in primary cultured rat hepatocytes examined by comet assay. In addition, MCE also enhanced bone marrow micronucleated polychromatic erythrocytes in mice. The analysis of HPLC showed that the main component of MCE was microcystin-LR. The understanding of the potent genotoxicity of MCE will help to establish the possible link between water cyanobacteria contamination and high risk of primary liver cancer found in some endemic areas.

Change in optic disc topography associated with diurnal variation in intraocular pressure

PURPOSE

A case demonstrating significant changes in optic disc topography from variation in intraocular pressure (IOP) is demonstrated.

METHODS

Within a single 24-hour period, confocal scanning laser ophthalmoscopic images were obtained in the left eye of a patient during an IOP peak (60 mmHg) and during an IOP trough (18 mmHg).

RESULTS

During an IOP trough, paired t tests showed significant reduction in cup area, cup volume, mean cup depth, and maximum cup depth, and a significant increase in rim area and cup-to-disc (CD) ratio.

CONCLUSION

Under certain conditions, optic disc topography may be affected by diurnal variations in IOP.

Molecular cloning and functional properties of two early-stage encapsulation-relating proteins from the coleopteran insect, Tenebrio molitor larvae

Encapsulation is a major defensive reaction against foreign materials that are too large to be phagocytosed by individual hemocytes; however, the biochemical process of encapsulation is still obscure. To isolate and characterize the early-stage encapsulation-relating protein (ERP), we used the coleopteran insect, Tenebrio molitor larvae, injecting three differing kinds of bead or inserting pieces of surgical suture into the abdomen of T. molitor larvae. The resulting proteins from the injected beads or the inserted pieces of surgical suture were recovered 10 min after injection or insertion, and were analyzed on SDS/PAGE under reducing conditions. Four different proteins (86, 78, 56 and 48 kDa) were enriched compared with the crude hemolymph. Among them, we purified 56-kDa and 48-kDa ERPs to homogeneity and raised polyclonal antibodies against each protein. Immunoblotting analysis showed that the affinity-purified antibodies of the 56-kDa and 48-kDa ERPs cross-reacted with the 48-kDa and 56-kDa ERPs, respectively. Analysis of the cDNA of 56-kDa ERP consisted of 579 amino acid residues and showed a novel glutamine-rich protein. Positive clones of the 48-kDa ERP showed the same DNA sequence as 56-kDa ERP. Interestingly, the chemically determined N-terminal amino acid sequence and the three partial amino acid sequences of the 48-kDa protein were found in the 56-kDa ERP, suggesting that the 48 kDa ERP was produced by the cleavage of Arg101-Gly102 of the 56-kDa ERP by a limited proteolysis. Western blotting analysis showed that these ERPs were detected exclusively on membrane fractions of hemocytes. Also, when the early-stage encapsulated beads were coated with both the 56-kDa and 48-kDa ERP antibodies and re-injected into larvae, no further encapsulation reaction was observed. However, when the early-stage encapsulated beads were incubated with 56-kDa ERP antibody, 48-kDa ERP antibody or nonimmunized rabbit IgG and re-injected into larvae, further encapsulation did occur.

An 86 kDa diapause protein 1-like protein is a component of early-staged encapsulation-relating proteins in coleopteran insect, Tenebrio molitor larvae

Recently, we reported two novel early-staged encapsulation-relating proteins (56 kDa and 48 kDa ERPs) isolated from the hemolymph of coleopteran insect, Tenebrio molitor larvae [Cho et al. (1999) Eur. J. Biochem. (in press)]. Here, a cDNA clone for another early-staged encapsulation-relating protein (86 kDa) was isolated. We found that the 86 kDa protein shows high homology with insect diapause protein 1. The 86 kDa protein was localized in the fat body and hemolymph, but not hemocyte lysate. A significant level of 86 kDa protein was detected in pre-pupae stage, but it decreased rapidly at late larvae and pupae, and no protein was found in embryo, early larvae and adult stages. This diapause protein 1-like protein is likely to be a component of early-staged encapsulation-relating proteins in the insect cellular defense reaction.

Automated high-performance liquid chromatographic method with precolumn reduction for the determination of ubiquinol and ubiquinone in human plasma

We developed a gradient HPLC method with automated precolumn reduction for direct electrochemical detection of ubiquinol-10 (CoQ10H2) and total coenzyme Q10 (TQ10) in human plasma. The concentration of ubiquinone-10 (CoQ10) was calculated by subtraction of CoQ10H2 from TQ10. Preparation of reducing agent and precolumn reduction was performed by a programmable auto-injector. The two mobile phases used were: A, 100% of methanol containing 50 mM sodium perchlorate and 10 mM perchloric acid; and B, a mixture of ethanol and tert.-butanol (80:20, v/v). Sample preparation was simply a deproteinisation process with 10-fold ethanol. A good linear relationship was obtained for CoQ10H2 concentration from 0.1 to 3 micromol/l. The detection limit was 2.5 nmol/l with an injection volume of 20 microl. The analytical recovery and reproduciblity were generally >90%. To validate the method, 18 freshly collected plasma samples of normal healthy subjects were analysed. The mean ratio of CoQ10H2/CoQ10 was 93:7. The proposed method is sensitive, reliable and can be used for clinical investigation.

Structural characteristics of tenecin 3, an insect antifungal protein

Tenecin 3, an antifungal protein, previously isolated from the insect Tenebrio molitor, inhibits growth of the fungus Candida albicans. However, the antifungal mechanism and functions of tenecin 3 remain unknown. As an initial step to study the mechanism and functions, physical and structural properties of tenecin 3 were examined by circular dichroism (CD) analysis and 2D nuclear overhauser effect spectroscopy. These analyses suggest that tenecin 3 has a propensity of random structure with very loose turn-like elements. The CD results also indicate that this random structural propensity is not significantly affected by temperature, pH, and by the presence of organic solvents or sodium dodecyl sulfate (SDS) micelles. However, the hydrodynamic studies suggest that tenecin 3 is not in extended form in spite of its random structural feature.

Rat osteopontin antibody is cross-reactive to a novel myelin-associated protein in chick

Osteopontin (OPN) was initially identified as glycosylated phosphoprotein in bones of vertebrates. Recently, OPN is reported to express in the primitive neuroepithelia of early chick embryonic hindbrain. We have demonstrated that rat OPN is immunohistochemically localized in the white matter of chick CNS. We have further confirmed the specificity of OPN cross-immunoreaction in myelin using demyelinated optic nerve induced by lysophosphatidylcholine (LPC), where the intensity of immunoreaction was closely related to the degree of demyelination. Immunoblot analyses showed that rat OPN antibody recognized a protein with molecular weights of approximately 47 kDa from chick CNS. Our data suggest that the antigen recognized by rat OPN is a previously undescribed myelin-associated protein in the chick CNS.

The pro-phenoloxidase of coleopteran insect, Tenebrio molitor, larvae was activated during cell clump/cell adhesion of insect cellular defense reactions

To characterize the proteins involved in cell clump/cell adhesion of insect cellular defense reactions, we induced the cell clump/cell adhesion reaction in vitro with the hemolymph of larvae of the coleopteran insect, Tenebrio molitor. The 72 kDa protein was specifically enriched in the residues of cell clump/cell adhesion and was purified to homogeneity. A cDNA clone for the 72 kDa protein was isolated. We found that the 72 kDa protein was an activated phenoloxidase from Tenebrio pro-phenoloxidase. We suggest that activated phenoloxidase is involved in the cell clump/cell adhesion reaction as well as in the synthesis of melanin.

Development of intracytoplasmic lumens in colon cancer cells cultured on non-adhesive surface

Cell-matrix interactions have important effects on phenotypic features, such as morphology, differentiation and cell growth. Several papers have suggested that when cell-matrix interaction is interrupted, cells grow as multicellular spheroids and eventually undergo apoptosis. We found that when ET(-), a laminin non-adherent colon cancer cell line, was cultured on poly-2-hydroxyethyl methacrylate (HEMA) coated plastic, the cells floated as cellular aggregates of spheroids or as single cells. Some of the single cells contained large intracytoplasmic lumens (ICL) and appeared similar to signet ring cells. These ICL were lined by a layer of short microvilli. The number of the cell did not increase when cultured on poly-HEMA. Another type of single cells, usually without ICL, demonstrated the characteristics of apoptotic cells by histologic examination. Acridine orange staining, flow cytometry and electron microscopy confirmed the apoptotic nature of those cells. On immunohistochemical staining for proliferating cell nuclear antigen, spheroids of cells and single cells with ICL were immunoreactive, while most of the single cells without ICL were negative. These results suggest that multicellular aggregates and formation of ICL were induced by the adaptation of ET(-) colon cancer cells in a harmful environment caused by reduced adhesiveness, and these changes might be related to cell survival.

Bacterial expression of tenecin 3, an insect antifungal protein isolated from Tenebrio molitor, and its efficient purification

Tenecin 3, an antifungal protein isolated from the insect Tenebrio molitor larvae, inhibits growth of the fungus Candida albicans. However, the antifungal mechanism and functions of tenecin 3 have not yet been studied due to its very low availability from the natural source. Here we report an expression system of the recombinant tenecin 3 in E. coli, whose amino acid composition is the same with that of the natural tenecin 3. We also devised a simple and easy procedure to isolate the recombinant protein from the bacterial cell extracts. The recombinant tenecin 3 showed an antifungal activity against C. albicans as the natural tenecin 3 did. Therefore large quantities of tenecin 3 can be easily obtained by the expression and purification system of tenecin 3 described in this report.

The definition of normal-tension glaucoma

PURPOSE

To evaluate the consistency of the definition of normal-tension glaucoma (NTG).

METHODS

All articles about NTG published between 1973 and 1997 from three clinical journals of ophthalmology were identified by a literature search. They were reviewed to determine criteria used to define NTG, including optic nerve assessment and intraocular pressure (IOP) requirements.

RESULTS

There were 63 articles identified that defined the disease entity NTG, including 30 published between 1973 and 1992 and 33 published between 1993 and 1997. Maximum IOP values acceptable for designation as NTG ranged from 17 mmHg to 26 mmHg. A significantly greater proportion of studies published during the last 5 years required maximum IOP values < or = 21 mmHg. Inclusion criteria based on structural characteristics of the glaucomatous optic disc or on the glaucomatous visual field were present in 55 (87%) and 56 (89%) articles, respectively. Of the seven articles that listed specific features classifying a disc as glaucomatous, seven (100%) were published within the last 5 years. Of the 13 articles that listed specific features classifying a field as glaucomatous, 9 (69%) were published within the last 5 years.

CONCLUSION

The criteria used to define NTG during the last 25 years have been highly variable. However, publications during the last 5 years have been more likely to require a maximum IOP < or = 21 mmHg and to describe specific features of the glaucomatous optic disc and visual field.

Differentiation of a colon cancer cell line on a reconstituted basement membrane in vitro

Basement membrane, a thin extracellular matrix, functions as a tissue stabilizer that promotes tissue integrity and differentiated phenotype. We studied a human colon cancer cell line, SNU 61, to evaluate its ability to differentiate on basement membrane. Cells were cultured on plastic, reconstituted basement membrane (Matrigel) or polyhydroxyethyl methacrylate (poly HEMA) for 72 h and evaluated by light and electron microscopy. On Matrigel, the cells showed gland formation with highly polarized cells containing basal nuclei and well developed brush border microvilli on the luminal surface. Apoptosis was noted mainly at the luminal side. On electron microscopic examination, numerous long microvilli, abundant cytoplasmic organelles and intercellular junctions were noted in the Matrigel-cultured cells. Intermediate cytoskeletons were scattered in the cytoplasm and existed on the axes of microvilli. Junctional complexes and desmosomes were frequently formed along intercellular spaces. The cells cultured on poly HEMA, on the other hand, were poorly differentiated and contained a few glandular structures with small lumens. Brush border microvilli, characteristic of enterocytic differentiation, were few in number and were developed on the basal surface. Intermediate filaments and microtubules were fewer than in the Matrigel-cultured cells. Carcinoembryonic antigen was expressed on the luminal surface of the Matrigel-cultured cells and in the cytoplasm of the poly HEMA cultured cells. CD44 stained the basolateral surface in the Matrigel-cultured cells, but the basal side was not stained in the poly HEMA cultured cells. These results are consistent with the different localization of microvilli in the Matrigel and in the poly HEMA cultured cells. Our observations suggest that human colon cancer cells on basement membrane can undergo glandular differentiation and that extracellular matrix is an important factor in morphogenesis.