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PubMed1990

The effect of currently available contact lens disinfection systems on Acanthamoeba castellanii and Acanthamoeba polyphaga.

Contact lens disinfection systems were evaluated for their effectiveness in killing Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites and cysts. Amoebae were inoculated into commercially available contact lens cleaning and soaking solutions. At intervals varying from 30 minutes to 24 hours, solutions were filtered. The filters were removed and cultured for Acanthamoeba organisms. Striking differences were observed in the abilities of the different disinfecting solutions to kill the organisms. Solutions containing chlorhexidine were effective at very short exposure times. Solutions containing benzalkonium chloride required slightly longer exposure times but were faster than solutions containing only thimerosal. Solutions containing sorbate, polyaminopropyl biguanide, or polyquaternium-1 were not effective at killing Acanthamoeba organisms in the time allotted for the experiment. Solutions containing hydrogen peroxide were quite effective if the agent was not prematurely catalyzed. A. polyphaga generally required longer exposure to disinfectants than did A. castellanii for complete inhibition to occur.

Acanthamoeba↗
PubMed1990

Deep corneal stromal opacities in long-term contact lens wear.

In 32 patients with long-term contact lens wear (up to 19 years), deep whitish opacities directly adjacent to Descemet's membrane were seen in the central part of the cornea. These opacities were seen in soft hydroxyethylmethacrylate (HEMA) as well as in hard (polymethylmethacrylate, PMMA) contact lens wear. These conditions could reduce visual acuity. When contact lens wear was discontinued or when the HEMA or PMMA lenses were replaced by gas-permeable rigid lenses, the lesions gradually diminished and resolved completely in most patients. One possible cause of these opacities is an allergic reaction to thimerosal. Another possible cause is chronic anoxia of the corneal stroma and endothelium. Endothelial cell density was not abnormal, but there was a marked polymegethism of the endothelium as a sign of endothelial stress.

Adult↗
PubMed1983

The preparation and safety of hepatitis B vaccine.

Preparation of hepatitis B vaccine in our laboratories consists of a series of steps that include initial concentration of surface antigen by ammonium sulphate precipitation, followed by isopycnic banding and rate zonal centrifugation in a K-II centrifuge. The partially purified antigen concentrate is digested with pepsin at pH 2 and the antigen is unfolded in 8 M urea solution followed by renaturation. After gel filtration, the antigen is treated with formalin in I :4000 dilution, adsorbed on to alum, and preserved with thimerosal. The final product contains essentially pure hepatitis B surface antigen. The process relies both on physical elimination of infectious virus particles and treatment with highly viral-destructive reagents in the pepsin (pH 2), urea and formalin steps. The process is known to be highly destructive of all known viruses tested and to include procedures that are known to be highly destructive of representatives of all known groups of animal viral agents. The three-step process in inactivation provides a fail-safe system for establishing safety of the product. Tests in more than 20000 persons, who are under surveillance, have shown no untoward effect and have confirmed the safety of the product.

Animals↗
PubMed2000

Antibodies for the prevention and treatment of viral diseases.

This paper reviews current use and evolving role of polyclonal and monoclonal antibody products for the prevention and treatment of viral diseases. Antibodies continue to be indicated for prophylaxis either prior to an anticipated exposure especially in situations of travel, or more commonly following an exposure. The predominant indication for use of antibody products is to prevent infection. With the availability of vaccines for the prevention of chickenpox, hepatitis A, hepatitis B, measles, rabies and smallpox, the role of passive immunization is reserved for susceptible individuals and those at high risk for complications of infection. Risks of transmission of infections associated with use of human plasma-derived products have been reduced by improvements in donor screening and virus removal and inactivation procedures. An additional safety concern has been addressed by the removal of thimerosal as a preservative. Within the last 5 years, two antibodies have been licensed for a viral indication, RespiGam and Synagis both for prevention of respiratory syncytial virus infection. RespiGam is a human plasma derived antibody and Synagis is a humanized monoclonal antibody, the first such antibody to be licensed for an infectious disease indication. CytoGam for prevention of cytomegalovirus infection in kidney transplant patients has recently been granted an expanded indication to include use in lung, liver, pancreas and heart transplant patients. As the use of therapeutics becomes more sophisticated, researchers may find better ways of using antibody products.

Antibodies, Monoclonal↗
PubMed2001

The role of calcium in the activation of glycogen phosphorylase in the fat body of the fruit beetle, Pachnoda sinuata, by hypertrehalosaemic hormone.

The role of calcium in the mediation of the hypertrehalosaemic signal of the endogenous neuropeptide Mem-CC was investigated in vitro and in vivo in the cetoniid beetle Pachnoda sinuata. The presence of Mem-CC increases the influx of extracellular 45Ca(2+) into the fat body as well as the efflux of 45Ca(2+) from pre-loaded fat body into the incubation medium. Extracellular calcium is essential to exert maximal activation of the fat body glycogen phosphorylase by saturating doses of Mem-CC (0.3 nM). This effect of extracellular Ca(2+) is dose-dependent: maximal activation of glycogen phosphorylase by Mem-CC is achieved at calcium concentrations of approximately 1.2 mM and the ED(50) was calculated to be 0.6 mM. Both, thimerosal and thapsigargin caused a stimulation of carbohydrate metabolism in the fat body, suggesting that a release of calcium from the endoplasmic reticulum is involved in this process. However, neither entry of extracellular calcium nor the release from the endoplasmic reticulum are sufficient alone for a full activation of the phosphorylase. The results of the present study suggest that calcium from extracellular as well as from intracellular sources is part of the second messenger system for the transduction of the hypertrehalosaemic signal of Mem-CC in the fat body of P. sinuata.

Animals↗
PubMed1986

Piroxicam-induced photosensitive dermatitis.

Eleven patients had piroxicam-induced photosensitivity when first seen. Six were photopatch-tested to piroxicam (2%, 5%, 20% concentrations); all tests were positive. This same group were patch test-positive to thimerosal. Three of the eleven patients became persistent light reactors. Two additional patients developed persistent hand dermatitis.

Adult↗
PubMed1989

Prevalence and relevance of allergic reactions in patients patch tested in North America--1984 to 1985.

Between Jan. 1, 1984, and May 1, 1985, 1199 patients with suspected allergic contact dermatitis were patch tested with 32 "standard" allergens, 707 patients with 19 "vehicle and preservative" allergens, and 613 patients with 10 "special study" allergens. Ten dermatologists representing nine geographic centers collected and analyzed data with the use of the American Academy of Dermatology's mainframe computer in Evanston, Illinois. The most common sensitizers identified were nickel, p-phenylenediamine, quaternium-15, neomycin, thimerosal, formaldehyde, cinnamic aldehyde, ethylenediamine, potassium dichromate, and thiuram mix. Each positive reaction was assessed for its clinical relevance.

Adult↗
PubMed1990

Rapid visual colorimetry of peritoneal lavage fluid.

STUDY HYPOTHESIS: That visual colorimetry can be used to rapidly and precisely estimate the erythrocyte count of 1:5 dilutions of simulated peritoneal lavage fluid. POPULATION: Fifty-four normal adult human subjects. METHODS: The automated or chamber RBC count is often used on fluid obtained by peritoneal lavage in patients with abdominal trauma to help determine the need for surgery. Unfortunately, this method sometimes results in excessive delay. We designed and built a simple colorimeter that facilitated rapid direct visual comparison of unknown samples with known color standards. A radiograph view box was used as a light source. Standards were prepared in 16-mm glass tubes to simulate peritoneal lavage fluid with RBC counts ranging from 0 to 140,000 in 10,000 cell/microL increments; 1:5 dilutions with water were used throughout to reduce opacity. Thimerosal was added to unknowns and standards to stabilize color; all samples were kept refrigerated at 4 C when not in use. In a double-blind in-vitro study, each subject matched 20 randomly distributed unknowns ranging from 12,000 to 131,000 erythrocytes/microL to the nearest standard. RESULTS: The mean absolute error for all 1,080 determinations was 3,560 RBC/microL (95% CI = 4,290-4,830; SD = 4,560; t = 39.6; df = 1,079; P less than .001). This method correctly predicted the RBC count to within 9,000 cells/microL 95% of the time. CONCLUSION: Visual comparison of 1:5 dilutions of simulated peritoneal lavage fluid with known color standards can be used to rapidly and precisely estimate the erythrocyte count.

Abdominal Injuries↗
PubMed1997

Calcium homeostasis and yeast phagocytosis in hemocytes of the colonial ascidian Botryllus schlosseri.

This paper reports the effects of drugs affecting the homeostasis of cytosolic-free calcium on in vitro yeast phagocytosis by hemocytes of the colonial ascidian Botryllus schlosseri. Significant inhibition of phagocytosis is observed after exposure of hemocytes to 10 microM or higher concentrations of thimerosal, which is known to deplete intracellular calcium stores in mammalian cells. The two calcium channel blockers nifedipine and verapamil significantly decrease the phagocytic index, the minimum effective concentrations being 10 and 50 microM, respectively. As these substances have no effects at lower concentrations, they probably act through the inhibition of Ca(2+)-ATPase activity, required to restock intracellular calcium stores, due to their interaction with calmodulin. Analogously, pimozide, which suppresses ATPase activity by interacting with calmodulin, and thapsigargin, which inhibits Ca(2+)-ATPase activity, significantly reduce the phagocytic index. Moreover, nifedipine, by altering cytosolic calcium homeostasis, also lowers the production of superoxide anion associated with phagocytosis. Results indicate that in ascidians, as in mammals, a rise in intracellular calcium is required for phagocyte activation and induction of the respiratory burst.

Animals↗
PubMed2002

The cannabinoids R(-)-7-hydroxy-delta-6-tetra-hydrocannabinol-dimethylheptyl (HU-210), 2-O-arachidonoylglycerylether (HU-310) and arachidonyl-2-chloroethylamide (ACEA) increase isoflurane provoked sleep duration by activation of cannabinoids 1 (CB1)-receptors in mice.

Cannabinoids produce antinociception via specific cannabinoid receptor activation, but there are also non-receptor mediated effects like for example the activation of the arachidonic acid cascade. Here we investigate the influence of cannabinoids (CB) on sleep duration after isoflurane anesthesia. We found that the CB receptor agonists R(-)-7-hydroxy-delta-6-tetra-hydrocannabinol-dimethylheptyl (HU-210) (0.1 mg/kg), 2-O-arachidonoylglycerylether (30 mg/kg) and arachidonyl-2-chloroethylamide (3 mg/kg) significantly prolong the duration of isoflurane induced sleep in mice (P<0.05). This effect was absent when co-injecting the selective CB(1) antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (1 mg/kg). Furthermore, HU-210 was ineffective in CB(1) receptor knockout mice (CB(1)-/-). Our behavioral tests (tail flick, rotarod) indicate that the sleep latency can be prolonged even at low drug dosages which do not influence thermal nociception. In the chosen dosages thimerosal (20 mg/kg), 2-AG (10 mg/kg), R(1)-methanandamide (R(1)-MAEA) (10 mg/kg) and flurbiprofen (27 mg/kg) were ineffective to increase sleep duration.

Anesthesia Recovery Period↗
PubMed2000

Nitric oxide reduces Ca(2+) and Zn(2+) influx through voltage-gated Ca(2+) channels and reduces Zn(2+) neurotoxicity.

The translocation of synaptic Zn(2+) from nerve terminals into selectively vulnerable neurons may contribute to the death of these neurons after global ischemia. We hypothesized that cellular Zn(2+) overload might be lethal for reasons similar to cellular Ca(2+) overload and tested the hypothesis that Zn(2+) neurotoxicity might be mediated by the activation of nitric oxide synthase. Although Zn(2+) (30-300microM) altered nitric oxide synthase activity in cerebellar extracts in solution, it did not affect nitric oxide synthase activity in cultured murine neocortical neurons. Cultured neurons exposed to 300-500microM Zn(2+) for 5min under depolarizing conditions developed widespread degeneration over the next 24h that was unaffected by the concurrent addition of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine. Furthermore, Zn(2+) neurotoxicity was attenuated when nitric oxide synthase activity in the cultures was induced by exposure to cytokines, exogenous nitric oxide was added or nitric oxide production was pharmacologically enhanced. The unexpected protective effect of nitric oxide against Zn(2+) toxicity may be explained, at least in part, by reduction of toxic Zn(2+) entry. Exposure to nitric oxide donors reduced Ba(2+) current through high-voltage activated calcium channels, as well as K(+)-stimulated neuronal uptake of 45Ca(2+) or 65Zn(2+). The oxidizing agents thimerosal and 2,2'-dithiodipyridine also reduced K(+)-stimulated cellular 45Ca(2+) uptake, while akylation of thiols by pretreatment with N-ethylmaleimide blocked the reduction of 45Ca(2+) uptake by a nitric oxide donor.The results suggest that Zn(2+)-induced neuronal death is not mediated by the activation of nitric oxide synthase; rather, available nitric oxide may attenuate Zn(2+) neurotoxicity by reducing Zn(2+) entry through voltage-gated Ca(2+) channels, perhaps by oxidizing key thiol groups.

Animals↗
PubMed1999

Flow injection analysis of mercury(II) in pharmaceuticals based on enzyme inhibition and biosensor detection.

An enzymatic amperometric procedure for measurement of mercury(II) in pharmaceuticals, based on the inhibition of invertase and on a glucose electrode was studied. Analytical parameters for measurements in batch and flow injection analysis (FIA) have been optimised. Mercury(II) was detected in the 10-60 ppb range with RSD < or =2%. A sample throughput of 6 h(-1) for batch and 15 h(-1) for FIA was obtained. The total mercury(II) from thimerosal (thiomersal, sodium ethylmercurithiosalicylate) in eye-drop samples was measured with the amperometric procedure after oxidative cleavage treatment. Results for both batch and FIA procedures correlated well with atomic absorbtion spectroscopy (AAS) data.

Biosensing Techniques↗
PubMed2003

Intracellular calcium handling in rat olfactory ensheathing cells and its role in axonal regeneration.

Intracellular calcium handling by rat olfactory ensheathing cells (OECs) is implicated in their support for regrowth of adult CNS neurites in a coculture model of axonal regeneration. Pretreatment of OECs with BAPTA-AM to sequester glial intracellular calcium ([Ca(2+)](i)) reduces significantly the numbers of cocultured neurons regrowing neurites. The mean resting [Ca(2+)](i) of OECs cultured alone or with neurons was 300 nM in an external solution containing 2.5 mM calcium ([Ca(2+)](o)). In high [K(+)](o) or zero [Ca(2+)](o), resting [Ca(2+)](i) significantly decreased. [Ca(2+)](i) significantly increased when [Ca(2+)](o) was increased to 20 mM, lonomycin, thapsigargin, and thimerosal increased [Ca(2+)](i), and caffeine, ryanodine, and cyclopiazonic acid were without effect. Of the receptor agonists tested, none induced a change in [Ca(2+)](i). The calcium influx induced by high [Ca(2+)](o) was blocked by La(3+) and SKF96365, partially inhibited by Cd(2+), and insensitive to Ni(2+) and nifedipine. Pretreatment of OECs with La(3+) reduced neurite regrowth in cocultures in a concentration-dependent manner over the range that blocked the non-voltage-gated calcium flux through a putative TRP-like channel, which, we propose, is activated in OEC-mediated axonal regeneration.

Animals↗
PubMedDate not supplied

Tyrosine kinase-mediated activation of cytosolic calcium oscillations and phasic myometrial contractions.

These studies sought to test the hypothesis that tyrosine kinase-stimulated phasic myometrial contractions are mediated by activation of the phosphatidylinositol (PI)-signaling pathway and the generation of cytosolic calcium oscillations. For these studies, uterine tissue was obtained from adult female Sprague-Dawley white rats during the proestrus/estrus phase of the cycle. In vitro contraction studies were performed using pervanadate (a tyrosine phosphatase inhibitor) with and without inhibitors of the PI-signaling pathway, including 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (a phospholipase C inhibitor), thimerosal (an inositol-trisphosphate receptor/channel inhibitor), and Ruthenium red (a ryanodine receptor inhibitor), and with oxytocin or prostaglandin F2 alpha (two classic uterotonic agonists). Cytosolic calcium studies were performed using Fura-2-loaded myometrial strips. During these studies, pervanadate was observed to produce cytosolic calcium oscillations and phasic contractions in myometrial tissue comparable to those produced in response to oxytocin and prostaglandin F2 alpha. The pervanadate-stimulated phasic contractions were significantly suppressed in response to inhibition of phospholipase C, the inositol-trisphosphate receptor, and the ryanodine receptor, thereby confirming the importance of the PI-signaling pathway during tyrosine kinase-associated myometrial activity. Further confirming the important and shared role for the PI-signaling pathway during pervanadate-stimulated myometrial contractions, no significant additive effects were observed when classic uterotonic agonists such as oxytocin or prostaglandin F2 alpha were combined with pervanadate.

Animals↗
PubMed2005

Atopy and contact hypersensitivity: a reassessment of the relationship using objective measures.

BACKGROUND: There is a big contradiction in the medical literature regarding the relationship between atopy and contact hypersensitivity. Some researchers believe that atopy would prevent, whereas others believe that it would promote, the development of contact allergy. Possible causes of this confusion range from different study populations to different definitions of atopy. OBJECTIVE: To evaluate the relationship between atopy and contact hypersensitivity in a well-defined general population sample using objectively measurable markers. METHODS: I studied 135 randomly selected students from 5 vocational schools: 73 women and 62 men aged 18 to 19 years. The following atopy markers were tested: positive skin prick test results, positive Phadiatop test results, and total IgE levels greater than 120 kU/L. Contact hypersensitivity was detected by using patch tests. Statistical analyses included the Fisher exact test, the Mann-Whitney U test, and calculation of odds ratios. RESULTS: At least 1 positive skin prick test result was found in 23.7% (95% confidence interval [CI], 16.5%-30.9%) of study participants, positive Phadiatop test results were found in 20.0% (95% CI, 13.3%-26.7%), and total IgE levels greater than 120 kU/L were found in 23.7% (95% CI, 16.5%-30.9%). Positive patch test reactions were found in 28.1% (95% CI, 20.6%-35.7%) of participants, most frequently to thimerosal (18.5%; 95% CI, 12.0%-25.1%) and nickel (9.6%; 95% CI, 4.6%-14.6%). For persons with atopy markers, odds ratios for contact hypersensitivity ranged from 1.0 to 3.2, the highest being for nickel hypersensitivity among those with total IgE levels greater than 120 kU/L. None of these relationships were statistically significant. CONCLUSION: Atopy and contact hypersensitivity are independent phenomena.

Adolescent↗
PubMed2004

Stimulation of the immune system by different TBE-virus vaccines.

Tick-borne encephalitis (TBE) is one of the most frequent arthropod-transmitted viral diseases in Europe. Different vaccines against TBE-virus have been developed; a thimerosal-free and also albumin-free vaccine [Ticovac (Baxter Hyland Immuno, Vienna)] was approved in 2000. Contrary to previous experience, 779 cases of fever occurred following the first vaccination of children under 15 years of age and in 62 children febrile convulsions were even observed. Consequently, the composition of the vaccine was changed and albumin was again added [FSME-Immun (Baxter Vaccines, Vienna)] in 2001. The new Encepur Kinder (Chiron-Behring, Marburg) from 2002 is a TBE-vaccine for children without any protein as stabilizer but with a relatively high concentration of sucrose, while the former vaccine Encepur K from 1991 contained polygeline as the stabilizer. The induction of the immune system by the different TBE virus vaccines was compared in an in vitro test in order to find an explanation for the unexpected fever attacks. Whole blood was stimulated with complete vaccine suspension, and TNF-alpha, IL-1beta, IL-6, and IL-8 were determined from heparin/EDTA-plasma and culture supernatants. It was shown that Ticovac and the new Encepur Kinder can induce relatively high amounts of TNF-alpha and lower amounts of IL-1beta. An increase of both cytokines was first observed following an incubation of 4 hours, with a maximum after 15 hours. Concentrations returned to base-line values within 26 hours. The behaviour of both cytokines correlates with the febrile phases in children up to two years old. Albumin or other proteins like polygeline and also immunoglobulins prevented a rise of cytokines.

Adjuvants, Immunologic↗
PubMed2001

Matrix metalloproteinase activities of turkey (Meleagris gallopavo) bile.

The bile from turkey (Meleagris gallopavo) gall bladders was found to contain substantial matrix metalloproteinase (MMP) activities using gelatin, collagen, and casein substrate zymography, [3H]labeled collagen degradation assays, and gelatin-agarose affinity purification. Five major bands corresponding to approximate M(w) of 64, 60, 46, 40 and 36 kDa showed gelatinolytic activities. On incubation with p-aminophenylmercuric acetate or thimerosal, the densities of both the 64- and 46-kDa bands decreased with increasing intensities of the 60- and 40-kDa bands. Both the 64- and 60-kDa bands showed collagenolytic activities whereas the caseinolytic activities appeared as diffuse bands corresponding to M(w) of approximately 60, 40 and 36 kDa. Using [3H]collagen as substrate, the bile enzymes showed both a time and concentration-dependent degradation, which could be inhibited by the MMP inhibitors such as EDTA, phenanthroline, and N-[(2R)-2-(hydroxyamido carbonylmethyl)-4-methylpentanonyl]-L-tryptophan methylamide, but not by serine and cysteine protease inhibitors like trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane, phenylmethylsulfonyl fluoride or leupeptin. Both 60- and the 40-kDa gelatinolytic bands showed affinity adsorption to a gelatin-agarose matrix. The physiological roles of bile MMPs are not clear, but their involvement in the digestive functions of birds are likely.

Animals↗
PubMed1999

Studies on the cytosolic phospholipase A2 in immortalized astrocytes (DITNC) revealed new properties of the calcium ionophore, A23187.

Besides playing an important role in the maintenance of cell membrane phospholipids, phospholipases A2 (PLA2) are responsible for the release of arachidonic acid (AA) which is a precursor for prostaglandin biosynthesis. The cytosolic PLA2 has been the focus of recent studies, probably due to its ability to respond to protein kinases and changes in intracellular calcium levels. In this study, we examined agents for stimulation of the cytosolic phospholipase A2 in immortalized astrocytes (DITNC). Incubation of DITNC cells with [14C]arachidonic acid (AA) resulted in a time-dependent uptake of the label into phospholipids (PL) and neutral glycerides. In prelabeled cells, release of labeled AA could be stimulated by calcium mobilizing agents such as calcium ionophore A23187 (4-20 microM) and thimerosal (100 microM), and by phorbol myristate acetate (PMA, 100 nM), an agent for activation of protein kinase C. The release of AA could also be stimulated by ATP (200 microM), probably through activation of the purinergic receptor but not by glutamate (1 mM). The stimulated release of AA was dependent on extracellular Ca2+ and was inhibited by mepacrine (50 microM), a non-specific PLA2 inhibitor. Western blot analysis further confirmed the presence of an 85 kDa cPLA2 in both membrane and cytosol fractions of these cells and stimulation by A23187 resulted in translocation of this protein to the membrane fraction. Besides labeled fatty acids, A23187 also stimulated the concomitant release of labeled PL into the culture medium and this event was accompanied by the increased release in lactate dehydrogenase (LDH). Results thus revealed that besides activation of cPLA2, the calcium ionophore A23187 is capable of perturbating cell membrane integrity.

Animals↗