Gene expression profiling of mouse teratocarcinomas uncovers epigenetic changes associated with the transformation of mouse embryonic stem cells

The molecular mechanisms of the development of teratocarcinomas from stem cells are largely unknown. To determine which genes are associated with the transformation of these cells, we have performed oligonucleotide microarray analysis, using Affymetrix U74A GeneChips, on both cell cultures and tumors in nude mice. We identified 68 genes that significantly differed in expression between the ES cell culture and the teratocarcinoma cell line, SCC-PSA1, and 51 genes with statistically different expression patterns between the ES cell tumors and the teratocarcinomas (P < .00005). We found that there were 20 genes that had common expression patterns in both groups. We also examined the role of the transition from in vitro to in vivo by comparing ES cell culture to ES cell tumor, and teratocarcinoma cell line to teratocarcinomas. We identified 22 genes that were upregulated in the ES cell tumors and 42 that had a decreased expression in the tumor (P < .0001). In comparing SCC-PSA1 to its tumor, we identified 34 upregulated genes and 25 downregulated genes (P < .001). There were only 10 genes in common from these two lists. GenMapp search revealed that several pathways, especially the cell cycle pathway, are actively involved in the induction of teratocarcinomas. Our results indicate that many key development genes may play a key role in the transformation of ES cells into teratocarcinoma cells.     

Suppression of angiogenesis and tumor growth by selective inhibition of angiopoietin-2

Angiopoietin-2 (Ang2) exhibits broad expression in the remodeling vasculature of human tumors but very limited expression in normal tissues, making it an attractive candidate target for antiangiogenic cancer therapy. To investigate the functional consequences of blocking Ang2 activity, we generated antibodies and peptide-Fc fusion proteins that potently and selectively neutralize the interaction between Ang2 and its receptor, Tie2. Systemic treatment of tumor-bearing mice with these Ang2-blocking agents resulted in tumor stasis, followed by elimination of all measurable tumor in a subset of animals. These effects were accompanied by reduced endothelial cell proliferation, consistent with an antiangiogenic therapeutic mechanism. Anti-Ang2 therapy also prevented VEGF-stimulated neovascularization in a rat corneal model of angiogenesis. These results imply that specific Ang2 inhibition may represent an effective antiangiogenic strategy for treating patients with solid tumors.     

Gentamicin-releasing urethral catheter for short-term catheterization

Urethral catheters, widely used for the drainage of the bladder, are associated with most urinary tract infections (UTIs) that account for 40% of all episodes occurring in acute-care hospitals. This study aimed to develop a gentamicin-releasing catheter that effectively prevents UTIs for short-term catheterization. For physical loading of gentamicin, the urethral catheters were coated by the simple dipping method with poly(ethylene-co-vinyl acetate) (EVA) and EVA/poly(ethylene oxide) (PEO) blends containing gentamicin. By varying the molecular weight (MW) and contents of PEO in the blends, various catheter surfaces were produced. In vitro drug release studies demonstrated that all the coated catheters exhibited sustained release up to 7 days; however, the release pattern was significantly dependant on the coating layers. Of the coated catheters, EVA/PEO (MW = 100k)-coated catheters were utilized to evaluate the antibacterial activity using an inhibition zone test, since they showed a promising drug release behavior and had PEO-rich biocompatible surfaces. In accordance with drug release behavior, EVA/PEO-coated catheters exhibited antibacterial activities for 7 days against Proteus vulgaris, Staphylococcus aureus and Staphylococcus epidermidis. These results imply that the catheters coated with EVA/PEO have a potential for short-term catheterization.     

Predictors of outcome in hospitalized patients with severe hyponatremia

Severe hyponatremia is associated with increased morbidity and mortality. Clinicians treating patients with severe hyponatremia are often torn between a desire to promptly raise serum sodium concentration to a "safe range," and at the same time, to avoid excessively rapid correction of hyponatremia. The aim of this study was to assess the prevalence of severe hyponatremia in hospitalized patients, the etiologic factors involved, as well as treatment and outcome of the patients using a retrospective case series. METHODS: Retrospective study of 168 patients with severe hyponatremia (< 115mmol/L) seen at Grady Memorial Hospital, a tertiary teaching hospital, in Atlanta, Georgia, from 1997-2001. The main outcome measures of interest were death during admission or occurrence of neurologic symptoms before, during or after therapy. RESULTS: One hundred sixty-eight patients met the inclusion criteria out of a total of 5994 patients with hyponatremia treated at our hospital over the study period. Eighty-nine patients (52.9%) were symptomatic. The mean absolute serum sodium at 48-hours of therapy was 120.02 +/- 8.31 mmol/L. Respiratory failure and/or hypoxia was present in 28 patients (16.7%); sepsis was documented in 16 patients (9.5%). Mortality rate was high, 34 patients died (20.2%). On multivariate analysis factors with strong association with mortality of patients with severe hyponatremia were hypoxia, presence of neurologic symptoms, slow correction rates and a diagnosis of sepsis. CONCLUSIONS: The mortality associated with severe hyponatremia remains high. Sepsis, respiratory failure and the presence of symptoms predict poor outcome in hospitalized patients with severe hyponatremia. More aggressive therapy with 3% saline may improve outcome in symptomatic patients. Our data suggest that a slow rate of correction in severe hyponatremia is associated with higher mortality than rapid correction, at least in the short-term.     

Elevated substance P levels in nasal lavage fluids from patients with chronic nonproductive cough and increased cough sensitivity to inhaled capsaicin

BACKGROUND: The exact mechanism of a chronic nonproductive cough is sometimes unclear when patients who are without symptoms or signs indicating the major causes of chronic cough remain undiagnosed. OBJECTIVE: We hypothesized that some neurochemical alterations in the sensory nerves in the cough reflex may occur in the upper airway of chronic nonproductive cough patients. METHODS: We took nasal lavage fluid (NLF) specimens from 38 patients with a chronic nonproductive cough as the sole presenting symptom. All 38 had normal chest radiography, spirometry, and bronchial responsiveness. We likewise took NLF specimens from 14 healthy control subjects. We used a capsaicin cough provocation test to determine cough sensitivity and considered the value of C5 (the lowest capsaicin concentration inducing 5 consecutive coughs) as an index of cough sensitivity. We measured levels of substance P of NLF specimens by using ELISA. In addition, we evaluated the clinical response of each patient after subsequent therapeutic trials with an antihistamine and decongestant for 2 weeks. RESULTS: By using capsaicin cough sensitivity as the basis for grouping the study subjects, we divided the patients into 2 groups: an increased cough sensitivity group (ICS, C5 <32 mumol/L) and a normal cough sensitivity (NCS) group. Patients with ICS showed an elevated SP concentration in NLF (median value, 408 pg/mL) compared with that of the NCS group (237 pg/mL) and the control subjects (138 pg/mL) (P <.01). The median value of the percentage of remnant cough after therapeutic trial compared with the cough status before treatment was significantly higher in the ICS subgroup (70%) than that of NCS (25%) (P <.05). CONCLUSIONS: Elevated substance P contents in NLF specimens were associated with ICS in patients with chronic nonproductive cough, suggesting a neurochemical abnormality in the upper airway.     

Cough sensitivity and extrathoracic airway responsiveness to inhaled capsaicin in chronic cough patients

Enhanced cough response has been frequently observed in chronic cough. Recently, extrathoracic airway constriction to inhaled histamine was demonstrated in some chronic cough patients. However, relation between extrathoracic airway hyperresponsiveness (EAHR) and cough sensitivity determined by capsaicin inhalation is unclear in each etiological entity of chronic cough. Seventy-seven patients, with dry cough persisting for 3 or more weeks, normal spirometry and chest radiography, and 15 controls, underwent methacholine bronchial provocation test and capsaicin cough provocation test. Elicited cough number and flow-volume curve was examined after inhalation of capsaicin to evaluate cough sensitivity and EAHR. Thirty-three patients, with postnasal drip, showed normal extrathoracic airway responsiveness, and 27 of them showed normal cough sensitivity to capsaicin. Cough sensitivity was enhanced in 14 patients with cough variant asthma (CVA) who showed bronchial hyperresponsiveness; EAHR to inhaled capsaicin was present in 12 of them. The remaining 30 patients were tentatively diagnosed as idiopathic chronic cough (ICC). Eleven ICC patients showed enhanced cough sensitivity and EAHR to inhaled capsaicin while 19 patients showed normal values. These results indicate that cough sensitivity is closely related with extrathoracic airway responsiveness during capsaicin provocation in some chronic cough patients. EAHR and enhanced cough sensitivity to inhaled capsaicin may be a part of mechanism developing chronic cough.     

Quantities of receptor molecules for colony stimulating factors on leukocytes in measles

We analyzed the comparative amounts of granulocyte-colony stimulating factor (G-CSFr) and granulocyte macrophage CSF (GM-CSFr) receptors expressed on neutrophils and monocytes in measles patients to investigate the role of these CSFrs in the development of leukopenia including neutropenia and monocytopenia in measles. EDTA-anticoagulated peripheral blood of 19 measles patients, 10 children with other infections showing leukopenia and 16 children with normal complete blood cell counts (CBC)s were analyzed using flow cytometry and QuantiBRITE. The leukocyte (5260 +/- 2030/uL vs. 9900 + 2680/uL, p=0.000), neutrophil (2580 +/- 960/uL vs. 4250 +/- 2750/uL, p=0.024) and the lymphocyte counts of measles patients (1810 +/- 1430/uL vs. 4530 +/- 3450/uL, p= 0.006) were lower than in the normal controls. The neutrophils of measles patients expressed similar amounts of G- CSFr (1858 +/- 355) as normal children (1764 +/- 477, p= 0.564) and leukopenic patients (1773 +/- 673, p=0.713), but lower levels of GM-CSFr (535 +/- 118) than normal children (957 +/- 344, p=0.000) and leukopenic patients (832 +/- 294, p=0.002). The monocytes of measles patients expressed similar amounts of G-CSFr (916 +/- 336) and GM-CSFr (3718 +/- 906) as normal children (1013 +/- 391 and 4125 (2645, p > 0.05) but less than leukopenic patients (1454 +/- 398 and 5388 +/- 806, p > 0.05). The neutrophil and monocyte counts of measles patients did not correlate with the amount of G-CSFr or GM-CSFr expressed on neutrophils or monocytes (p > 0.05), but in the normal children, the monocyte count correlated with the levels of GM-CSFr on monocytes (r=0.951, p=0.049). In conclusion, neutropenia is one of the more important characteristics of measles patients, which could be due to the decreased GM-CSFr expression on neutrophils. However, the monocytopenia found in measles patients is not due to the decreased expression of CSFr on the monocytes.     

Prevalence of pachycondyla chinensis venom allergy in an ant-infested area in Korea

Recently, immediate allergic reactions, including anaphylaxis, after Pachycondyla chinensis ant stings have been frequently reported in Korea. To estimate the prevalence of these reactions and the sensitization rate to P chinensis, we undertook a visit-questionnaire survey of the 327 adult residents living in a town in an ant-infested area in Korea. Skin prick tests with 6 common inhalant allergens, 3 bee venom allergens, and P chinensis whole body extract were performed on all ant-allergic subjects, on 86 asymptomatic residents, and on 37 controls outside the area. The serum-specific IgE to P chinensis extract was determined by ELISA. Seven subjects (2.1%) reported that they had experienced systemic allergic reactions to P chinensis stings; 4 of them had anaphylactic reactions. Large local reactions occurred in an additional 5 subjects (1.6%). All subjects with systemic allergic reactions had positive skin prick test results to P chinensis extract, whereas 23.3% of asymptomatic residents and 2.7% of the controls showed positive skin prick test results. The serum-specific IgE level was significantly higher in the subjects with systemic reactions than in the subjects with local reactions, the asymptomatic sensitizers, and the nonatopic controls. Sensitization to bee venom was found in 25% of the P chinensis -allergic subjects; this was significantly higher than the 3% rate seen in nonsensitized subjects. In conclusion, we report a 2.1% prevalence of systemic allergic reactions after P chinensis stings, based on self-reported symptoms, in an ant-infested area in Korea.     

Peroxynitrite scavenging activity of lithospermate B from Salvia miltiorrhiza

Peroxynitrite (ONOO-) is produced by the reaction of superoxide (O2-) with nitric oxide. ONOO- damages proteins through nitration or oxidation. For protection from ONOO- induced protein modifications, ONOO- scavengers should be supplemented. Evidence was obtained that lithospermate B extracted from Salvia miltiorrhiza showed the strongest scavenging activity among its constituents. Its ONOO- scavenging activity is via an electron donation mechanism. A dihydroxyl group and a double bond seem to be essential structure requirements. The data from the experiments further confirmed a protective effect of lithospermate B on bovine serum albumin and low-density lipoprotein against ONOO-. This study demonstrated that lithospermate B with hydroxyl groups and double bonds exerts an anti-nitration effect by scavenging ONOO-.