Mental Health Literacy in Cancer Outpatients in Singapore.

OBJECTIVE: We aimed to evaluate the prevalence of depressive and anxiety symptoms and mental health literacy (MHL) in outpatients with or without cancer in Singapore. METHODS: Oncology outpatients and outpatients without cancer (controls) were assessed for severity of anxiety and depressive symptoms (using the Hospital Anxiety and Depression Scale) and MHL regarding major depressive disorder and generalised anxiety disorder in terms of diagnosis, aetiology, treatment, and attitudes toward mental health services. RESULTS: A total of 89 oncology outpatients and 61 controls were recruited. Those with primary and secondary education had significantly lower MHL scores than those with university education (p = 0.001). Oncology outpatients and controls were comparable in terms of anxiety (13.5% vs 9.8%, p = 0.5), depression (2.2% vs 1.6%, p > 0.99), and total MHL score (7.94 vs 9.13, p = 0.102). CONCLUSIONS: MHL is comparable between oncology outpatients and controls and is positively associated with education level.

Molecular basis for the production of cyclic peptides by plant asparaginyl endopeptidases.

Asparaginyl endopeptidases (AEPs) are proteases that have crucial roles in plant defense and seed storage protein maturation. Select plant AEPs, however, do not function as proteases but as transpeptidases (ligases) catalyzing the intra-molecular ligation of peptide termini, which leads to peptide cyclization. These ligase-type AEPs have potential biotechnological applications ranging from in vitro peptide engineering to plant molecular farming, but the structural features enabling these enzymes to catalyze peptide ligation/cyclization rather than proteolysis are currently unknown. Here, we compare the sequences, structures, and functions of diverse plant AEPs by combining molecular modeling, sequence space analysis, and functional testing in planta. We find that changes within the substrate-binding pocket and an adjacent loop, here named the "marker of ligase activity", together play a key role for AEP ligase efficiency. Identification of these structural determinants may facilitate the discovery of more ligase-type AEPs and the engineering of AEPs with tailored catalytic properties.

Amyloidogenicity and aggregate cytotoxicity of human glucagon-like peptide-1 (hGLP-1).

The potential of human glucagon-like peptide-1 (hGLP-1) as a therapeutic agent is limited by its high aggregation propensity. We show that hGLP-1 forms amyloid-like structures that are preceded by cytotoxic aggregates, suggesting that aggregation of biopharmaceuticals could present a cytotoxic risk to patients besides the reported increased risk in immunogenicity.

Therapeutic targets in extracellular protein deposition diseases.

Many litres of fluids are found outside cells in the human body. These fluids are rich in dissolved proteins that each have a characteristic three dimensional shape, necessary for normal function, which has been attained by the correct folding of their polypeptide chain(s). The structure of these extracellular proteins can be damaged by a variety of environmental stresses (e.g. heat and oxidation) leading to their partial unfolding and aggregation. This in turn can produce toxic soluble aggregates and/or large insoluble protein deposits, either of which can disrupt normal body function (e.g. in Alzheimer's disease and the systemic amyloidoses). A small family of abundant human blood proteins with the ability to inhibit the aggregation and deposition of stressed (partially unfolded) proteins has been discovered. These extracellular chaperones (ECs) form stable, soluble complexes with stressed proteins. It has been proposed that once bound to stressed proteins, ECs guide them to specific cell surface receptors that direct the "cargo" into lysosomes for degradation. Thus ECs and their receptors may be critical parts of a quality control system to protect the body against the deleterious effects of inappropriately aggregating extracellular proteins. This review focuses on the role of extracellular protein aggregation and deposition in disease, what little is known about mechanisms that act to control these processes, and, lastly, potential new targets for drug development. Newly identified potential drug targets include direct inhibition of protein aggregation, and manipulation of the expression levels of ECs and their receptors.

Improvement of tissue-adhesive obliteration of bleeding gastric varices using adjuvant hypertonic glucose injection: a prospective randomized trial.

BACKGROUND AND STUDY AIMS: Rebleeding can occur after endoscopic injection of gastric varices with tissue adhesive. The aim of this study was to evaluate whether adjuvant hypertonic glucose solution injections enhance the effects of Histoacryl after successful initial variceal obliteration. PATIENTS AND METHODS: A total of 67 patients (37 men, 30 women; mean age +/- standard deviation [SD] 60 +/- 17 years) with initially successful Histoacryl obliteration of bleeding gastric varices were included in the study and randomly divided into two groups: a "combined" group of patients who had adjuvant injection of hypertonic glucose solutions in cases of residual gastric varices (F1 or less) and a "control" group of patients who did not receive such therapy. End points were either variceal recurrence/progression (F2 or more) requiring Histoacryl reinjection or rebleeding. RESULTS: Residual small varices were found in 56% of patients in the combined group and in 60% of patients in the control group. Adjuvant therapy was only performed in the combined group. During the follow-up period (mean duration +/- SD 37.9 +/- 18.5 months, range 19-56 months), two patients in the combined group showed gastric variceal progression, compared with nine patients showing progression in the control group, with two cases of rebleeding, both occurring in the control group. Two years after the first Histoacryl injection, the cumulative proportion of patients who did not have gastric variceal progression was significantly higher in the combined group than it was in the control group (92.8% vs. 71.4%, P = 0.029). There was no significant difference between the two groups with respect to their survival curves (P = 0.12). No marked immediate or delayed symptoms or complications were observed in the patients given hypertonic glucose injections. CONCLUSIONS: Adjuvant treatment with hypertonic glucose solution for residual small gastric varices is a safe and simple method. It helps reduce the recurrence or progression of gastric varices after tissue adhesive injections and can therefore reduce the risk of rebleeding.

Effects of uptake and efflux transporter inhibition on erythromycin breath test results.

The erythromycin breath test (EBT) is a standard test used to evaluate the extent of CYP3A4 activity. This study examines whether presumed changes in CYP3A4 activity are in fact related to inhibition of an uptake organic anion transporter using rifampin and inhibition of the efflux hepatic P-glycoprotein transporter using lansoprazole. Three EBT tests in healthy adults were conducted: EBT alone, with lansoprazole, and with rifampin. For all subjects, lansoprazole treatment increased respiratory (14)C excretion by +0.25+/-0.51 met/h (P=0.07) and rifampin decreased (14)C excretion by -0.44+/-0.40 met/h (P<0.001) compared with baseline. Comparing lansoprazole to rifampin, (14)C excretion increased by +0.69+/-0.50 met/h (P<0.001). Only women had significant changes after drug infusion: (14)C excretion after rifampin -0.40+/-0.36 met/h (P=0.018) and +0.47+/-0.44 met/h (P=0.018) after lansoprazole. Relying on EBT without considering transporter interactions can lead to errors in interpreting the degree of CYP3A4 metabolism.

Thyroid hormone receptor-interacting protein 1 modulates cytokine and nuclear hormone signaling in erythroid cells.

Erythropoietin (Epo) and thyroid hormone (T(3)) are key molecules in the development of red blood cells. We have shown previously that the tyrosine kinase Lyn is involved in differentiation signals emanating from an activated erythropoietin receptor. Here we demonstrate that Lyn interacts with thyroid hormone receptor-interacting protein 1 (Trip-1), a transcriptional regulator associated with the T(3) receptor, providing a link between the Epo and T(3) signaling pathways. Trip-1 co-localized with Lyn and the T(3) receptor alpha in the cytoplasm/plasma membrane of erythroid cells but translocated to discrete nuclear foci shortly after Epo-induced differentiation. Our data reveal that T(3) stimulated the proliferation of immature erythroid cells, and inhibited maturation promoted by erythropoietin. Removal of T(3) reduced cell division and enhanced terminal differentiation. This was accompanied by large increases in the cell cycle inhibitor p27(Kip1) and by increasing expression of erythroid transcription factors GATA-1, EKLF, and NF-E2. Strikingly, a truncated Trip-1 inhibited both erythropoietin-induced maturation and T(3)-initiated cell division. This mutant Trip-1 acted in a dominant negative fashion by eliminating endogenous Lyn, elevating p27(Kip1), and blocking T(3) response elements. These data demonstrate that Trip-1 can simultaneously modulate responses involving both cytokine and nuclear receptors.

The effect of jejunal meal feeding on gastroesophageal reflux.

BACKGROUND: Postprandial gastric distention is frequently associated with transient lower esophageal sphincter relaxation and gastroesophageal reflux (GER). Since the role of nutrient perfusion into the jejunum in inducing GER is not well understood, we studied the effect of jejunal feeding on GER through a percutaneous gastrojejunal tube in patients with and without reflux esophagitis. METHODS: Nine stroke patients with reflux esophagitis were fed through a percutaneous gastrojejunal tube with either a liquid meal (2 kcal/2 ml/min) or saline for 2 h randomly on 2 separate days. An esophageal pH probe was placed 5 cm above the gastroesophageal junction to detect acid reflux. Six stroke patients without esophagitis were enrolled as controls. RESULTS: In both the patients with esophagitis and the controls, esophageal acid exposure (15.3% (4.9%-28.2%) versus 2.7% (0.0%-10.8%), P=0.003; 5.9% (0.5%-6.7%) versus 0.0% (0.0%-1.5%), P = 0.01) and events of acid reflux (5 (1-16) versus 2 (0-8), P = 0.02; 12 (3-17) versus 1 (0-4), P = 0.02) were significantly greater during jejunal meal feeding than during saline infusion. Furthermore, in the reflux patients, but not in the controls, acid clearance time was also greater during jejunal meal feeding than during saline infusion (2.9 min (0.5-9.6 min) versus 0.7 min (0.0-4.3 min), P = 0.04). CONCLUSIONS: We therefore conclude that jejunal nutrient infusion without gastric distention can induce GER in both patients with reflux esophagitis and controls. This implies that GER induced by jejununal nutrients may in part explain the incapability of jejunal tube feeding to prevent gastropulmonary aspiration in patients at risk.

Clusterin is an ATP-independent chaperone with very broad substrate specificity that stabilizes stressed proteins in a folding-competent state.

We recently reported that the ubiquitous, secreted protein clusterin has chaperone activity in vitro [Humphreys et al. (1999) J. Biol. Chem. 274, 6875-6881]. In this study, we demonstrate that clusterin (i) inhibits stress-induced precipitation of a very broad range of structurally divergent protein substrates, (ii) binds irreversibly via an ATP-independent mechanism to stressed proteins to form solubilized high molecular weight complexes, (iii) lacks detectable ATPase activity, (iv) when acting alone, does not effect refolding of stressed proteins in vitro, and (v) stabilizes stressed proteins in a state competent for refolding by heat shock protein 70 (HSP70). Furthermore, we show that, at physiological levels, clusterin inhibits stress-induced precipitation of proteins in undiluted human serum. Clusterin represents the first identified secreted mammalian chaperone. However, reports from others suggest that, at least under stress conditions, clusterin may be retained within cells to exert a protective effect. Regardless of the topological site(s) of action, the demonstration that clusterin can stabilize stressed proteins in a refolding-competent state suggests that, during stresses, the action of clusterin may inhibit rapid and irreversible protein precipitation and produce a reservoir of inactive but stabilized molecules from which other refolding chaperones can subsequently salvage functional proteins.

Immune control of HIV-1 after early treatment of acute infection.

Virus-specific T-helper cells are considered critical for the control of chronic viral infections. Successful treatment of acute HIV-1 infection leads to augmentation of these responses, but whether this enhances immune control has not been determined. We administered one or two supervised treatment interruptions to eight subjects with treated acute infection, with the plan to restart therapy if viral load exceeded 5,000 copies of HIV-1 RNA per millilitre of plasma (the level at which therapy has been typically recommended) for three consecutive weeks, or 50,000 RNA copies per ml at one time. Here we show that, despite rebound in viraemia, all subjects were able to achieve at least a transient steady state off therapy with viral load below 5,000 RNA copies per ml. At present, five out of eight subjects remain off therapy with viral loads of less than 500 RNA copies per ml plasma after a median 6.5 months (range 5-8.7 months). We observed increased virus-specific cytotoxic T lymphocytes and maintained T-helper-cell responses in all. Our data indicate that functional immune responses can be augmented in a chronic viral infection, and provide rationale for immunotherapy in HIV-1 infection.

Effect of premedication guidelines and leukoreduction on the rate of febrile nonhaemolytic platelet transfusion reactions.

Platelet transfusion reactions were prospectively studied in haematology/oncology patients at five university teaching hospitals over three consecutive summers. The initial summer study provided baseline information on the use of premedications and the rate of platelet transfusion reactions (fever, chills, rigors and hives). Most (73%) platelet recipients were premedicated and 30% (95% CI 28-33%) of transfusions were complicated by reactions. The second study followed implementation of guidelines for premedicating platelet transfusions. Despite a marked reduction in premedication (50%), there was little change in the platelet transfusion reaction rate, 26% (95% CI 24-29%), or the type of reactions. The third study followed implementation of prestorage platelet leukoreduction while maintaining the premedication guidelines. The reaction rate decreased to 19% (95% CI 17-22%). For nonleukoreduced platelets, there was a statistically significant association between the platelet age and reaction rate (P = 0.04). For leukoreduced platelets, there was no statistically significant association between platelet age and reaction rate (P = 0.5). Plasma reduction of nonleukoreduced platelet products also reduced the reaction rate. These prospective studies document a high rate of platelet transfusion reactions in haematology/oncology patients and indicate premedication use can be reduced without increasing the reaction rate. Prestorage leukoreduction and/or plasma reduction of platelet products reduces but does not eliminate febrile nonhemolytic platelet transfusion reactions.

Endoscopic treatment of bleeding gastric varices by N-butyl-2-cyanoacrylate (Histoacryl) injection: long-term efficacy and safety.

BACKGROUND: The long-term efficacy and safety of the endoscopic injection of N-butyl-2-cyanoacrylate (Histoacryl) were evaluated to define its role as the initial treatment for bleeding gastric varices. METHODS: Ninety patients with bleeding gastric varices underwent endoscopic injections of Histoacryl for hemostasis within a 6-year period. Histoacryl was injected intravariceally as a 1:1 mixture with Lipiodol. Among the 90 patients, 5 had active bleeding and 85 had recent bleeding. Most of the varices were large (F2 or F3, 85 cases). The most common locations were the fundus and the posterior wall of the proximal body (94.4%). After Histoacryl injection, patients were followed endoscopically with retreatment as necessary. RESULTS: The rate of hemostasis at 1 week was 94.4%. Recurrent bleeding occurred in 23.3% of the patients from 3 days to 16 months after the initial injection. Recurrent bleeding was stopped with reinjections of Histoacryl in 16.7% of the patients. The rate of definitive hemostasis was 93.3% (84 of 90). The treatment failure-related mortality rate was 2.2% (2 of 90). To date, 35 patients have died, mostly as a result of malignancy or liver failure, and 55 are still alive. The determining factor for long-term survival was the underlying disease leading to portal hypertension. There were few long-term complications except for Histoacryl cast extrusion-related mucosal defects. CONCLUSIONS: Endoscopic injection of Histoacryl is highly effective for the treatment of bleeding gastric varices, with rare complications both acutely and long term. This treatment modality is appropriate as the first choice for bleeding gastric varices.

Measurement of telomere length in haematopoietic cells using in situ hybridization techniques.

The DNA of human chromosomes terminates in several kilobases of telomere repeats that are gradually lost with; age and with replication in vitro. Defective telomere maintenance has been shown to be causally linked to cell cycle exit and apoptosis. In order to overcome the limitations imposed by Southern blotting, we have established a quantitative fluorescence in situ hybridization (Q-FISH) technique. This technique allows estimation of telomere length in specific chromosome arms from metaphase cell preparations. Furthermore, we have extended quantitative in situ hybridization to flow cytometry (flow FISH) in order to obtain information on the mean telomere repeat content in suspended cells. Telomere length in granulocytes, monocytes, CD8 and CD4 T lymphocytes and natural killer cells was found to differ slightly in the peripheral blood of adults. However, strikingly longer telomeres were observed in B lymphocytes (approximately 1.3 kb longer), suggesting a functional role for telomere maintenance in this cell subset. In summary, Q-FISH and flow FISH represent new methods for measuring telomere length in single cells and allow studies of telomere dynamics in haematopoietic subpopulations at various stages of normal and abnormal antigen responses.

Ultrastructure and function of the fractalkine mucin domain in CX(3)C chemokine domain presentation.

Fractalkine (FKN), a CX(3)C chemokine/mucin hybrid molecule on endothelium, functions as an adhesion molecule to capture and induce firm adhesion of a subset of leukocytes in a selectin- and integrin-independent manner. We hypothesized that the FKN mucin domain may be important for its function in adhesion, and tested the ability of secreted alkaline phosphatase (SEAP) fusion proteins containing the entire extracellular region (FKN-SEAP), the chemokine domain (CX3C-SEAP), or the mucin domain (mucin-SEAP) to support firm adhesion under flow. CX3C-SEAP induced suboptimal firm adhesion of resting peripheral blood mononuclear cells, compared with FKN-SEAP, and mucin-SEAP induced no firm adhesion. CX3C-SEAP and FKN-SEAP bound to CX(3)CR1 with similar affinities. By electron microscopy, fractalkine was 29 nm in length with a long stalk (mucin domain), and a globular head (CX(3)C). To test the function of the mucin domain, a chimeric protein replacing the mucin domain with a rod-like segment of E-selectin was constructed. This chimeric protein gave the same adhesion of peripheral blood mononuclear cells as intact FKN, both when immobilized on glass and when expressed on the cell surface. This implies that the function of the mucin domain is to provide a stalk, extending the chemokine domain away from the endothelial cell surface to present it to flowing leukocytes.

Heterogeneous Helicobacter pylori isolates from H. pylori-infected couples in Taiwan.

Helicobacter pylori strain diversity was investigated in 55 H. pylori seropositive couples in Taiwan in biopsy samples from the antrum and corpus. Two DNA typing methods were used to characterize 90 isolates from 25 couples. In only 1 of the 25 couples was the same strain colonized from both partners. Comparison of isolates from 2 sites in each of 40 patients showed that 9 pairs were distinct but might be related. Peptic ulcer occurred in 77.8% of these 9 patients compared with 29% of 31 patients with the same predominant strain in 2 biopsies (P=.025). Random amplified polymorphic DNA and sequence analyses of 2 closely related isolates from 1 patient support the hypothesis that development of genetic diversity of H. pylori results from horizontal genetic exchange during long-term colonization of mixed bacterial populations.

Telomere length measurements using digital fluorescence microscopy.

BACKGROUND: The ends of chromosomes (telomeres) are important to maintain chromosome stability, and the loss of telomere repeat sequences has been implicated in cellular senescence and genomic instability of cancer cells. The traditional method for measuring the length of telomeres (Southern analysis) requires a large number of cells (>10(5)) and does not provide information on the telomere length of individual chromosomes. Here, we describe a digital image microscopy system for measurements of the fluorescence intensity derived from telomere repeat sequences in metaphase cells following quantitative fluorescence in situ hybridization (Q-FISH). METHODS: Samples are prepared for microscopy using Q-FISH with Cy3 labeled peptide nucleic acid probes specific for (T(2)AG(3))(n) sequences and the DNA dye DAPI. Separate images of Cy3 and DAPI fluorescence are acquired and processed with a dedicated computer program (TFL-TELO). With the program, the integrated fluorescence intensity value for each telomere, which is proportional to the number of hybridized probes, is calculated and presented to the user. RESULTS: Indirect tests of our method were performed using simulated as well as defined tests objects. The precision and consistency of human telomere length measurements was then analyzed in a number of experiments. It was found that by averaging the results of less than 30 cells, a good indication of the telomere length (SD of 10-15%) can be obtained. CONCLUSIONS: We demonstrate that accurate and repeatable fluorescence intensity measurements can be made from Q-FISH images that provide information on the length of telomere repeats at individual chromosomes from limited number of cells.

Absence or low number of telomere repeats at junctions of dicentric chromosomes.

Human ovarian surface epithelial (HOSE) cells transfected with the E6 and E7 oncogenes of the human papilloma virus (PV) do not express measurable telomerase activity. Relative to untransfected control cells, HOSE-PV cells have an extended in vitro lifespan characterized by a very high frequency of telomeric associations (TAs) of chromosomes. In order to study the role of telomere shortening in the formation of TAs, we studied the telomere length in 120 dicentric chromosomes in HOSE-PV cells by using quantitative fluorescence in situ hybridization. Forty percent of the dicentric chromosomes had no fluorescence signal at the junction site, and in the remainder the fluorescence at the junction was less than at corresponding unjoined ends. These observations support a critical role of telomere shortening in the development of TAs and the subsequent genetic instability observed in a majority of tumor cells.

Electrogastrographic study of the effect of transcatheter arterial chemoembolization on gastric myoelectric activity.

BACKGROUND: Transcatheter arterial chemoembolization (TACE) of the hepatic artery is frequently used in the treatment of inoperable hepatocellular carcinoma (HCC). TACE causes not only effective tumor tissue necrosis in patients with hepatoma but also adverse effects on extrahepatic abdominal organs. There are no published reports on the effect of TACE on the gastric myoelectric activity. In this study, using cutaneous electrogastrography (EGG), we evaluated the effect of TACE on gastric myoelectric activity in patients with HCC. METHODS: A total of 27 patients (24 men and 3 women, aged 22 to 78 years) with hepatoma, admitted for TACE, were included in this study. Furthermore, 28 patients (24 men and 4 women, aged 26 to 75 years), admitted for diagnostic angiography of the liver, served as the control group. Cutaneous EGG was performed before and after TACE or angiography. RESULTS: In the TACE group there were significant changes in dominant frequency (DF) and percentages of DF in the defined normal range, bradygastric range, and tachygastric range on post-meal EGG. On fasting EGG, only the dominant frequency and percentages of DF in the bradygastric range changed significantly. However, there was no correlation between the occurrence of nausea/vomiting and the degree of change in the EGG variables, during both fasting and postprandial states. In the control group there were no significant differences in EGG variables before and after angiography. CONCLUSIONS: TACE can affect gastric myoelectric activity in HCC patients. Nevertheless, the relationship between changes in myoelectric activity and the occurrence of gastrointestinal symptoms needs further investigation.

Radionuclide imaging in primary amyloidosis with liver involvement.

A 74-year-old man with hepatomegaly, hyperglycemia, and proteinuria was diagnosed with primary amyloidosis with liver involvement, proven by biopsy. Abnormal distribution of tracer in the liver on Tc-99m phytate liver-spleen imaging and abnormal tracer uptake by the liver on Tc-99m pyrophosphate whole body imaging were observed. Scintigraphic imaging studies may be used noninvasively to evaluate the involvement of organs in patients with primary amyloidosis, reducing the risk of bleeding caused by biopsy.