Glioblastoma stem cells: a new target for metformin and arsenic trioxide.

The high malignancy of glioblastoma has been recently attributed to the presence, within the tumor, of glioblastoma stem cells (GSC) poorly responsive to chemo- and radiotherapy. Here, the potential employment of metformin and arsenic trioxide (ATO) in glioblastoma therapy is discussed focusing on their effects on GSC. Metformin exerts anticancer effects by primarily blocking the pivotal LKB1/AMPK/mTOR/S6K1 pathway-dependent cell growth, induces selective lethal effects on GSC by impairing the GSC-initiating spherogenesis and inhibits the proliferation of CD133+ cells, while having a low or null effect on differentiated glioblastoma cells and normal human stem cells. Metformin and ATO induce autophagy and apoptosis in glioma cells by inhibiting and stimulating the PI3K/Akt and the mitogen-activated protein kinase pathways, respectively. Both drugs promote differentiation of GSC into non-tumorigenic cells. In this regard, metformin acts via activation of the AMPK-FOXO3 axis, whereas ATO blocks the interleukin 6-induced promotion of STAT3 phosphorylation. Blood-brain barrier, easily crossed by metformin but not by ATO, undergoes important glioblastoma-induced alterations that increase its permeability, thus allowing ATO to distribute more into the glioblastoma bulk than in the normal brain parenchyma. A prompt clinical assessment of metformin and ATO in glioblastoma patients would represent a valid attempt to improve their survival.

Zinc opposes genotoxicity of cadmium and vanadium but not of lead.

Protection by essential metals against the genotoxic effects of toxic elements is an open question. Here, human Hs27 dermal fibroblasts and B-mel melanoblasts were exposed for 10 days to (1 µM) zinc (Zn) or copper (Cu) or selenium (+ 4, Sei; + 6, Sea). Afterwards, cells were exposed for 3 days to subtoxic concentrations of lead (Pb, 100 µM) or vanadium (+ 5, V, 2 µM) or cadmium (Cd, 3 µM), slightly reducing, by themselves, cell proliferation and unaffecting cell viability and apoptosis. Genotoxic damage was evaluated by cytokinesis-block micronucleus assay (CBMN) and single cell gel electrophoresis (Comet assay, CA). CBMN and CA were preliminarly assessed following 3, 10 and 30 days of exposure to the above concentrations of Pb, V and Cd: Pb induced micronuclei (MN) formation in both Hs27 and B-mel cells, without determining direct DNA damage (as shown by CA); V did not reveal genotoxic effects on fibroblasts (as shown by CBMN and CA) but increased the frequency of MN and comets in melanoblasts; Cd induced a great number of MN and comets in fibroblasts but not in melanoblasts; all these effects did not differ after 3, 10 or 30 days of exposure to such elements so that Hs27 and B-mel cells were exposed to Pb,V and Cd for 3 days following pretreatment with (1 µM) Zn, Cu, Sei or Sea. By itself, the 10 day-exposure to (1 µM) Zn, Cu, Sei or Sea did not affect cell proliferation, viability, apoptosis and formation of MN or comets in either Hs27 or B-mel cells. Only Zn significantly reduced the Cd- and V-induced MN and comet formation in fibroblasts and melanoblasts, respectively; in these cells, however, Zn did not affect the Pb-induced MN formation. These results emphasize the role of Zn, in respect to other essential metals, in opposing the genotoxic effects of cancerogenic (Cd) or potentially cancerogenic elements (V).

Acute mercury intoxication and use of chelating agents.

There is a great hazard of mercury intoxication in the third world for artisanal miners using mercury as amalgam for extracting and refining gold. In developing countries, there is the possibility of risk regarding exposure to Hg from amalgam tooth fillings, ethyl-Hg (thimerosal) added as antiseptic to vaccines and methyl-Hg in fish. In one case, a 41-year-old man attempted suicide by ingesting 100 mg of HgCl2. After 8 hours, he developed hematemesis and entered the intensive care unit; his urinary Hg was 10.1 mg/l. Treatment with 2,3-dimercaptopropanol (BAL) was started by intramuscular route after 16 hours at the dosage of 5 mg/kg body weight every 4 hours on days 2-3 and 3 mg/kg every 6 hours on days 4-5 and then every 12 hours on days 6-14 without adverse side effects. Acute Hg intoxication can be managed with BAL as first choice chelator, whereas the less toxic 2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercaptopropane-1-sulfonic acid (DMPS) should be reserved for cases of less severe inorganic Hg or methyl-Hg acute intoxication. Such agents, recommended only for the treatment of acute Hg poisoning, should not be used for patients suffering from neurological diseases in which environmental Hg exposure is hypothesised.

Shock induction by arterial hypoperfusion of the gut involves synergistic interactions between the peripheral enkephalin and nitric oxide systems.

To determine whether critical splanchnic artery hypoperfusion can provoke systemic shock and to identify the roles of the peripheral opioid and nitric oxide (NO) systems in this process, various degrees of superior mesenteric artery hypoperfusion (SMA-H) were produced in anesthetized adult rabbits (n=40), and hemodynamic and metabolic indices were measured. Metabolic acidosis and irreversible hypodynamic shock occurred with SMA-H at levels representing 25-20% of mean baseline SMA blood flow. In 112 other rabbits subjected to SMA-H at 20% (SMA-H20%), we studied plasma NO and enkephalin (ENK) levels, cardiovascular reactivity to selected physiological agonists, effects of ENKs on plasma NO levels, and effects of peripheral opioid receptor blockade and inducible NO synthase (iNOS) inhibition. SMA-H20% progressively increased systemic blood levels of NO and ENKs. Exogenous ENK administration accentuated SMA-H20%-induced increases in plasma NO levels, and their cardiovascular depressing effects were significantly greater when they were administered during SMA-H20% (vs. administration under baseline conditions). Selective blockade of cardiovascular delta-opioid receptors improved hemodynamics, prevented shock irreversibility and reduced plasma NO levels; similar effects were obtained by selective iNOS inhibition. These findings demonstrate that critical arterial hypoperfusion of the gut can induce hypodynamic systemic shock through ENK-induced hyperactivation of cardiovascular delta-opioid receptors, which leads to increased plasma levels of NO related in part to increased iNOS activity. Since pronounced splanchnic artery hypoperfusion occurs in all advanced systemic shock states, selective delta-opioid receptor antagonists and/or iNOS inhibitors may prove to be useful in improving shock hemodynamics and metabolic derangements and/or preventing progression toward irreversibility.

Neurobehavioral functions, serum prolactin and plasma renin activity of manganese-exposed workers.

Objective of this study was to assess effects of manganese (Mn) exposure on 56 workers employed in a Mn welding workshop of a machine building factory in Taiyuan (Shanxi Province, P.R. China) for a mean period of 16.1 years. The mean air Mn level in the workshop was 138.4 microg/m3. Neurobehavioral Core Test Battery (NCTB), including the Profile fo Mood States, (POMS), was performed. Blood pressure (BP) increase following immediate stand-up (BP-IS), serum prolactin (PRL) and plasma renin activity (PRA) in supine position were also determine. Most of the NCTB scores of the Mn-exposed workers were lower than those of controls, while the POMS scores were higher, indicating a Mn-induced impairment of neurophysiological functions and a deflection of mood towards negative emotion states. PRL values of the Mn-exposed workers were higher than those of the controls. BP-IS of Mn-exposed workers was significantly lower than that of the controls. PRA of the same workers was augmented more that 200%. In the Mn-exposed workers, the higher PRL values are possibly due to a reduced inhibitory effect on pituitary lactotrope cells by the tubero-infundibular dopamine system; the decreased BP-IS was referred to imbalance between the sympathetic and parasympathetic activities, whereas the higher basal PRA was thought to depend on neuroendocrine changes (including increased central sympathetic tone) and/or on a direct effect of Mn on renal juxta-glomerular cells. On the whole, this study demonstrates that occupational Mn exposure is responsible for neurobehavioral changes coexisting with alterations of neuroendocrine and humoral systems.

Clastogenic but not apoptotic effects on human artery endothelial cells by concentrations of inorganic lead inhibiting their nitric oxide production.

Human coronary artery endothelial cells (HCAEC 5156) were cultured as monolayers and exposed to concentrations of lead (as acetate, Pb) in the culture medium similar or lower than those commonly found in the blood of human beings occupationally or environmentally exposed to this element. Only at the concentration of 200 ng/mL, Pb reduced growth rate of HCAEC 5156 cells starting from the 3rd day and up too the 5th day of incubation. On the other hand, Pb (0.2, 2 and 200 ng/mL) increased concentration-dependently micronuclei formation in binucleated HCAEC 5156 cells, as it was shown by the cytokinesis-blocked micronucleus assay (CMBN assay) carried out after 48 hours of exposure to the metal. However Pb was unable, at all the above concentrations to induce apoptosis in the HCAEC 5156 cells following a 48 hour-exposure, as shown by an electorphoretic apoptotic DNA fragmentation test. Moreover, Pb (2 and 200 ng/mL) reduced significantly the concentration of nitric oxide (NO, determined analytically as L-citrulline) in both culture medium and cytosol of HCAEC 5156 cells following a 7 day-exposure to the element. Results were discussed also in relation so evidences of other studies reporting genotoxic and/or apoptotic effects of Pb on various cell types at very elevated dosages of concentrations. The observed clastogenic effects of Pb were explained through a series of mechanisms involving interactions between oxygen reactive species and NO and/or reduced NO synthesis in the endothelium, thus leading to a depressed NO bioavailability. This research first shows that Pb is provided with clastogenic but not apoptotic effects on cultured human endothelial cells. It was emphasized that such effects are induced by Pb concentrations similar to those commonly found in blood and tissues of laboratory animals showing Pb induced cardiovascular and/or neuropsychological alterations.

The enhanced anticaries efficacy of a sodium fluoride and dicalcium phosphate dihydrate dentifrice in a dual-chambered tube. A 2-year caries clinical study on children in the United States of America.

PURPOSE: To clinically evaluate and compare a dentifrice system in a dual-chambered tube, wherein one chamber contained sodium fluoride in a silica base and the other chamber contained dicalcium phosphate dihydrate (Test Dentifrice delivering 0.243% sodium fluoride), to a dentifrice containing 0.243% sodium fluoride in a silica base (Positive Control Dentifrice). MATERIALS AND METHODS: This study was conducted in harmony with the published 1988 American Dental Association guidelines for studies geared toward the comparison of fluoride dentifrices. This 2-yr caries clinical study employed a double-blind, parallel-group design, and involved 5-17 yr-old children from the Central and South areas of Florida and from the Lares area of Puerto Rico. Qualifying subjects were stratified according to age and sex, and were randomly assigned to the two treatment groups, with multiple subjects in the same household all assigned to the dentifrice randomly allocated to the first among them. Caries examinations were conducted in accordance with U.S. Food and Drug Administration guidelines for the clinical evaluation of drugs to prevent dental caries. Two calibrated examiners performed all the measurements. After treatment assignment, study participants were instructed to brush their teeth at home with their assigned dentifrice at least twice daily. Brushing instructions were reinforced by indoctrination in proper oral hygiene techniques by dental professionals, supplemented by pamphlets supplied by the sponsor and yearly mailings to participants, emphasizing good oral hygiene and the need to enforce compliance with the study. Post-baseline examinations were performed after 1 yr of product use, and again after 2 yrs of product use. RESULTS: Two thousand five hundred six (2,506) subjects completed this 2-yr study. For these subjects, the mean caries scores (DMFS, decayed, missing and filled tooth surfaces) at baseline were 2.29 for the Test Dentifrice group, and 2.47 for the Positive Control Dentifrice group. For caries increments after 1 yr, the respective means were 0.69 for the Test Dentifrice group and 0.81 for the Positive Control Dentifrice group. Finally, after 2 yrs, the mean caries increments were 1.25 for the Test Dentifrice group, and 1.46 for the Positive Control Dentifrice group. No statistically significant difference was indicated between the treatment groups at baseline or between the 1-yr caries increment scores. However, there was a statistically significant difference in the 2-yr caries increment scores between the treatment groups. Relative to the Positive Control Dentifrice group, the Test Dentifrice group presented a 14.38% reduction in caries increment scores at 2 yrs. In accordance with the procedures and standards provided by the published guidelines of the American Dental Association for the comparison of the anticaries efficacy of fluoride dentifrices, the results of this study support the conclusion that the dentifrice system in a dual-chambered tube, wherein one chamber contained sodium fluoride in a silica base and the other chamber contained dicalcium phosphate dihydrate, delivering 0.243% sodium fluoride, provided a superior level of anticaries efficacy than did the dentifrice containing 0.243% sodium fluoride in a silica base.

The enhanced anticaries efficacy of a sodium fluoride and dicalcium phosphate dihydrate dentifrice in a dual-chambered tube. A 2-year caries clinical study on children in Brazil.

PURPOSE: To clinically evaluate and compare a dentifrice system in a dual-chambered tube, wherein one chamber contained sodium fluoride in a silica base and the other chamber contained dicalcium phosphate dihydrate (Test Dentifrice delivering 0.243% sodium fluoride), to a dentifrice containing 0.243% sodium fluoride in a silica base (Positive Control Dentifrice). MATERIALS AND METHODS: This study was conducted in harmony with the published 1988 American Dental Association guidelines for studies geared toward the comparison of fluoride dentifrices. This 2-yr caries clinical study employed a double-blind, parallel-group design, and involved 6-10 yr-old children from the metropolitan area of Maceio, Alagoas, Brazil. Qualifying subjects were stratified according to age and sex, and were randomly assigned to the two treatment groups, with multiple subjects in the same household all assigned to the dentifrice randomly allocated to the first among them. Caries examinations were conducted in accordance with U.S. Food and Drug Administration guidelines for the clinical evaluation of drugs to prevent dental caries. One calibrated examiner performed all the measurements. After treatment assignment, study participants were instructed to brush their teeth at home with their assigned dentifrice at least twice daily. Brushing instructions were reinforced by indoctrination in proper oral hygiene techniques by dental professionals, supplemented by pamphlets supplied by the sponsor and yearly mailings to participants, emphasizing good oral hygiene and the need to enforce compliance with the study. Post-baseline examinations were performed after 1 yr of product use, and again after 2 yrs of product use. RESULTS: Two thousand four hundred thirty-two (2,432) subjects completed this 2-yr study. For these subjects, the mean caries scores (DMFS, decayed, missing and filled tooth surfaces) at baseline were 3.84 for the Test Dentifrice group, and 4.06 for the Positive Control Dentifrice group. For caries increments after 1 yr, the respective means were 2.02 for the Test Dentifrice group and 2.12 for the Positive Control Dentifrice group. Finally, after 2 yrs, the mean caries increments were 4.30 for the Test Dentifrice group, and 4.83 for the Positive Control Dentifrice group. No statistically significant difference was indicated between the treatment groups at baseline or between the 1-yr caries increment scores. However, there was a statistically significant difference in the 2-yr caries increment scores between the treatment groups. Relative to the Positive Control Dentifrice group, the Test Dentifrice group presented a 10.97% reduction in caries increment scores at 2 yrs. In accordance with the procedures and standards provided by the published guidelines of the American Dental Association for the comparison of the anticaries efficacy of fluoride dentifrices, the results of this study support the conclusion that the dentifrice system in a dual-chambered tube, wherein one chamber contained sodium fluoride in a silica base and the other chamber contained dicalcium phosphate dihydrate, delivering 0.243% sodium fluoride, provided a superior level of anticaries efficacy than did the dentifrice containing 0.243% sodium fluoride in a silica base.

The comparative anticaries efficacy of a dentifrice containing 0.3% triclosan and 2.0% copolymer in a 0.243% sodium fluoride/silica base and a dentifrice containing 0.243% sodium fluoride/silica base: a two-year coronal caries clinical trial on adults in Israel.

The purpose of this two-year clinical study was to provide a comparison of the anticaries efficacy associated with two commercially available, American Dental Association-accepted dentifrices: Colgate Total Toothpaste, which contains 0.3% triclosan and 2% copolymer in a 0.243% sodium fluoride/silica base; and Crest Cavity Fighting Toothpaste with Fluoristat, which contains 0.243% sodium fluoride in a silica base. The study was conducted in harmony with the published 1988 American Dental Association guidelines for studies geared toward the comparison of fluoride dentifrices. The study employed a double-blind parallel-group design, and involved adults living in communities throughout Israel. Qualifying subjects were randomly assigned to the two treatment groups, with multiple subjects in the same household all assigned to the dentifrice randomly allocated to the first among them. Caries examinations were conducted in accordance with U.S. Food and Drug Administration guidelines for the clinical evaluation of drugs to prevent dental caries. Two calibrated examiners performed all of the measurements. After treatment assignment, study participants were instructed to brush their teeth at home with their assigned dentifrice at least twice daily. Brushing instructions were reinforced by indoctrination in proper oral hygiene techniques by dental professionals, supplemented by pamphlets supplied by the sponsor and yearly mailings to participants, emphasizing good oral hygiene and the need to ensure compliance with the study. Post-baseline examinations were performed after one year of product use, and again after two years of product use. Three-thousand, three-hundred and ninety-two (3,392) subjects completed this two-year study. For these subjects, the mean caries scores (DFS, decayed or filled surfaces) at baseline were 21.96 for the Colgate Total Toothpaste group, and 21.49 for the Crest Cavity Fighting Toothpaste with Fluoristat group. For caries increment after one year, the respective means were 1.37 for the Colgate Total Toothpaste group, and 1.56 for the Crest Cavity Fighting Toothpaste with Fluoristat group. After two years, the mean caries increments were 1.46 for the Colgate Total Toothpaste group, and 1.75 for the Crest Cavity Fighting Toothpaste with Fluoristat group. No statically significant difference was indicated between the treatment groups at baseline. However, for both the one-year and two-year increments, there was a statistically significant difference between treatment groups. Relative to the Crest Cavity Fighting Toothpaste with Fluoristat group, the Colgate Total Toothpaste group presented a 12.2% reduction in caries increment scores at one year, and a 16.6% reduction in caries increment scores at two years. In accordance with the procedures and standards provided by the published guidelines of the American Dental Association for the comparison of the anticaries efficacy of fluoride dentifrices, the results of this study support the conclusion that Colgate Total Toothpaste provides a superior level of coronal anticaries efficacy compared to Crest Cavity Fighting Toothpaste with Fluoristat.

The comparative plaque removal efficacy of two advanced manual toothbrush designs in two independent clinical studies.

Two independent studies were conducted to evaluate and compare the clinical performance of two commercially available manual toothbrushes (Colgate Total Professional and the Oral-B Cross Action). Study I was a short-term, examiner-blind crossover clinical trial (N = 30) designed to measure the removal of 24-hour plaque build-up. All subjects refrained from brushing for 24 hours and were screened for dental plaque on the facial and lingual surfaces of all natural teeth using the Rustogi Modified Navy Plaque Index. Patients then received one of the two study toothbrushes and brushed their teeth for a timed one minute. They were then re-assessed for plaque. The data showed that the Colgate Total Professional toothbrush performed better than the Oral-B Cross Action toothbrush in reducing whole-mouth plaque scores (p < 0.001). Study II was a definitive six-week, single-blind clinical trial (N = 55), conducted in harmony with American Dental Association guidelines, to assess the ability of the two toothbrushes to reduce supragingival plaque and gingivitis. In this study, the subjects were stratified into two balanced groups based on their baseline plaque and gingivitis scores. Subjects were then instructed to continue with their normal brushing technique twice daily for one minute with their assigned toothbrush and a commercially available dentifrice. Examinations for plaque (Rustogi Modified Navy Plaque Index), and gingivitis (Loe-Silness Gingival Index) were conducted by the same examiner at baseline, after three weeks, and again after six weeks. The data from this long-term clinical trial showed that the Colgate Total Professional toothbrush exhibited statistically significantly lower plaque and gingivitis scores than did the Oral-B Cross Action toothbrush. The magnitudes of these differences were 29.5% for plaque and 31.1% for gingivitis. These reductions are adequate to support the claim that the Colgate Total Professional toothbrush provides clinically superior control of supragingival plaque and gingivitis, when studied in accordance with the criteria provided by the 1999 Guidelines of the American Dental Association for determining superiority.

Novel hypotensive agents from Verbesina caracasana. 8. Synthesis and pharmacology of (3,4-dimethoxycinnamoyl)-N(1)-agmatine and synthetic analogues.

The more polar metabolites from the Venezuelan plant Verbesina caracasana, i.e., N(3)-prenylagmatine, (3,4-dimethoxycinnamoyl)-N(1)-agmatine, agmatine, and galegine (prenylguanidine), previously reported (Delle Monache, G.; et al. BioMed. Chem. Lett. 1999, 9, 3249-3254), have been synthesized following a biosynthetic strategy. The pharmacologic profiles of various synthetic analogues of (3,4-dimethoxycinnamoyl)-N(1)-agmatine (G5) were also analyzed, to shed some light on the structure-activity relationship of these compounds. Derivatives with the (E)-configuration and/or with a p-methoxybenzoyl moiety were found to be responsible for higher hypotensive effects, which were associated with a slight and, in some cases, not dose-related increase of cardiac inotropism, with variable and not significant chronotopic responses, and, only at higher doses, with effects of respiratory depression. Either an increase (to six) or a decrease (to two) of the number of methylene groups in the alkyl chain of (E)-G5 did not change blood pressure responses, while slightly increasing the positive inotropic ones. At pharmacological doses, all the studied compounds showed hypotensive and slight positive inotropic effects without relevant chronotropic and respiratory actions.

Occurrence of torus palatinus and mandibularis among women of different ethnic groups.

PURPOSE: To detect the presence of tori in women of different ethnic groups residing in the metropolitan area of Washington, D.C., USA. MATERIALS AND METHODS: 448 females between the ages of 18-88 years participated in the study. There were 302 African Americans, 62 Caucasians, 43 Hispanics, 36 Asians, and 5 Native Americans. RESULTS: Tori were detected in 107 African Americans (35.4%), 20 Caucasians (32.3%), 13 Hispanics (30.2%), 14 Asians (38.9%), and 1 of the 5 Native American (20%), (P = 0.328). Torus palatinus were found in 69.7% of women from all ethnic groups (P = 0.107). Slightly higher percentage was seen in the Hispanics, then the African Americans, with the least in the Caucasians. Torus mandibularis were found only in 38.7% of all subjects (P< 0.05), were more common among Caucasians, and were usually bilateral. The presence of both tori was only detected in 8.4% of the participants. There was no relationship between age and the presence of torus mandibularis (r = 0.074) or palatinus (r = 0.008).

Lymphocyte subpopulations, cytokines and trace elements in asymptomatic atopic women exposed to an urban environment.

This study evaluates the immune response to exposure to an urban environment from 30 non-atopic and 30 non-symptomatic women with history of respiratory and/or cutaneous allergies. Blood lymphocyte subsets and serum interleukin (IL) 4 and interferon gamma (INF-gamma) of the two groups were similar, while serum IgE and "in vitro" production of IL-4 and INF-gamma by mononuclear blood cells of the atopic women were higher spontaneously or in the presence of PHA, respectively. Blood lead of the nonatopic women (mean 55 microg/l) was positively correlated with CD4+-CD45RO-, CD3+-CD8+ and CD3--HLA-DR+ lymphocyte subsets, while urinary trans-trans muconic acid (a metabolite of benzene) of both groups of women (mean about 50 microg/l) was significantly correlated with NK CD16+CD56+ lymphocytes. Urine chromium of the non-atopic subjects was significantly correlated with activated T, B and NK HLA-DR+ cells. Urine nickel of both groups of women was correlated with CD4+-CD45RO+ "memory" lymphocytes and their ratio with CD4+-CD45RO- "virgin" lymphocytes suggesting that the metal enhances maturation of "virgin" into "memory" lymphocytes. On the whole, this study demonstrates that exposure to low levels of toxic agents, produced by vehicular traffic in an urban environment, exerts effects on immune functions of women.

Increase in CD45RO+ cells and activated eosinophils in chronic allergic conjunctivitis.

We assessed the infiltration of CD45RO+ cells in conjunctival biopsies of fifteen subjects affected by seasonal allergic conjunctivitis by means of immunohistochemistry. Correlations between infiltration of CD45RO+ cells and serum and mucosal indices of eosinophilic activation were investigated. The study was performed in autumn and all selected patients showed <> also in absence of sensitising pollens. Fifteen healthy subjects were used as controls. The semi-quantitative count of CD45RO+ cells in biopsy specimens demonstrated that positive cells were higher in allergic patients than in controls (p < 0.001) and EG2+ eosinophils were present only in biopsies of allergic patients. Furthermore, a statistically significant positive correlation (r = 0.73; p < 0.001) between CD45RO+ lymphocytes and EG2 positive eosinophils, was observed in the biopsies of allergic patients. Total serum IgE significantly correlated with CD45RO+ cells (r = 0.61; p < 0.02) and EG2+ eosinophils (r = 0.67; p < 0.01) in the conjunctiva. On the other hand serum ECP did not correlate with any histological and immunohistochemical parameters in the conjunctival biopsies. The present study shows that mild symptoms in SCA patients out of pollen season are associated with inflammation of the conjunctiva as shown by an increased number of CD45RO and EG2 positive cells.

In vitro cleavage by asbestos fibers of the fifth component of human complement through free-radical generation and kallikrein activation.

Chrysotile and crocidolite fibers incubated in normal human plasma (NHP) generated from the C5 component of complement C5a-type fragments that stimulated polymorphonuclear leukocyte (PMN) chemotaxis. Absorption of NHP with antiserum against C5a totally abolished neutrophil chemotactic activity. Asbestos fibers also produced C5a small peptides in the presence of ethylene glycol bis(beta-aminoethyl ether) N,N,N'N'-tetraacetic acid (EGTA) but not ethylene diamine tetraacetic acid (EDTA). Activation of C5 was significantly inhibited when asbestos fibers were pretreated with iron chelators such as sodium dithionite (DTN), deferoxamine (DFX), or ascorbate (AA). Concentration-related inhibition of C5 activation was also observed when asbestos fibers were added concurrently to plasma in the presence of DFX, 1,3-dimethyl-2-thiourea (DMTU), a strong hydroxyl scavenger, or aprotinin (APR), a specific protease inhibitor. Further, chrysotile and crocidolite significantly increased plasma kallikrein activity. Data demonstrate that asbestos-induced C5 activation plays a role in inflammatory reactions characteristic of asbestosis through mechanisms involving iron ions, hydroxyl radicals, and oxidized C5-ike fragments. The ferrous ions present at the asbestos fiber surface trigger this activation and catalyze, via Fenton reaction, the production of hydroxyl radicals, which in turn convert native C5 to an oxidized C5-like form. This product is then cleaved by kallikrein, activated by the same asbestos fibers, yielding an oxidized C5a with the same functional properties as C5a.

Catcholamine and nitric oxide systems as targets of chronic lead exposure in inducing selective functional impairment.

Rats were exposed for ten months to 60 ppm of lead (Pb, as acetate) in drinking water to further assess cardiovascular effects of chronic Pb exposure. At the end of the treatment, mean blood Pb was 3.1+/-0.3 microg/dL in the control rats and 22.8+/-1.2 microg/dL in the Pb-exposed rats (means+/-SE, n=12 in each group); these values were not comparable to those of humans. Pb greatly increased plasma levels of noradrenaline (NA) and adrenaline (A), but not those of L-DOPA and dopamine; monoaminoxidase activity was augmented by Pb, mostly in the aorta and in the liver; the aorta, liver, heart and kidney showed discrete histopathological alterations in the Pb-exposed rats, in which plasma levels of nitric oxide (NO, determined as L-citrulline) were reduced. Pb was able to induce blood hypertension, resulting from increase of cardiac inotropism and, mostly, total peripheral resistance. These data were discussed also in relation to those obtained in our previous studies carried out in rats exposed to Pb in drinking water (15-60 ppm) for periods ranging from five to eighteen months. Pb appeared to increase both sympathetic nerve activity by central mechanisms (thus increasing plasma NA and A) and cyclic adenosine monophosphate (cAMP)-dependent availability of calcium ions (Ca++) for contractile mechanisms in the vascular and cardiac myocells (also through an increased vascular alpha2- and myocardial beta1-adrenoreceptor reactivity). The reduction of plasma NO, contributing to increase vascular resistance and cardiac inotropism, was explained as a result of actions of Pb on enzyme activities concerned with the kallikrein-kinin (KK) and renin-angiotensin-aldosterone (RAA) systems. It was concluded that chronic Pb exposure is able to affect selective neuroendocrine (i.e., catecholamine), au- tacoidal (i.e., KK and RAA) and transductional pathways (i.e., cAMP, NO, Ca++) involved in the cardiovascular function.

A new desensitizing dentifrice--an 8-week clinical investigation.

An 8-week, double-blind, three-way clinical trial compared the dentinal hypersensitivity-reducing effectiveness of a new dentifrice containing 5.0% potassium nitrate and 0.454% stannous fluoride in a silica base (Colgate Sensitive Maximum Strength Toothpaste, Colgate-Palmolive Co.) with a commercially available desensitizing dentifrice containing 5.0% potassium nitrate and 0.243% sodium fluoride in a silica base (Sensodyne Fresh Mint Toothpaste, Block Drug Company, Inc.) and a nondesensitizing dentifrice containing 0.243% sodium fluoride in a silica base (Colgate Winterfresh Gel, Colgate-Palmolive Co.). One hundred nine subjects were stratified into three balanced groups according to gender, age, mean baseline tactile (Yeaple Probe), and thermal (air blast) scores. The test products were randomly assigned to each group with instructions to brush twice daily. Oral examinations with tactile and thermal assessments were repeated after 4 and 8 weeks. The new dentifrice group demonstrated statistically significant improvements in tactile and thermal sensitivity over the two control groups.