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Biomedical subjects

I Roman

Publications and source records attributed to I Roman.

At least 19 recordsLinked to original sources
PubMed2004

Prophylactic management of children at risk for recurrent upper respiratory infections: the Preventia I Study.

BACKGROUND: Given the morbidity and mortality of asthma and the recent dramatic increase in its prevalence, pharmacologic prophylaxis of this disease in children at risk would represent a major medical advance. OBJECTIVES: The Preventia I Study was designed to evaluate the efficacy and long-term safety of loratadine in reducing the number of respiratory infections in children at 24 months. A secondary objective was to investigate the benefit of loratadine treatment in preventing the onset of respiratory exacerbations. METHODS: Preventia I was a randomized placebo-controlled study involving 22 countries worldwide. The children were 12-30 months of age at enrollment and had experienced at least five episodes of ENT infections, and no more than two episodes of wheezing during the previous 12 months. Phase I was a 12-month double-blind period during which the children were treated with loratadine 5 mg/day (2.5 mg/day for children</=24 months of age) or placebo. Phase II was a double-blind follow-up period without study medication. RESULTS: Of the 412 children enrolled, 342 and 310 completed Phase I and Phase II, respectively. The results showed a significant decrease in the number of infections in the whole population of children. However, no difference was observed between the loratadine and placebo group. When considering secondary end-points, loratadine was shown to reduce the number of respiratory exacerbations during the treatment phase. None of the 204 children who received loratadine discontinued the study because of drug-related events. Loratadine treatment was not more sedative than placebo and was not associated with cardiovascular events. CONCLUSION: The strong decrease in the rate of infections in the children at risk of recurrent infections, while not being influenced by loratadine treatment, should encourage future reflection in terms of prophylactic management. This study also confirms the long-term safety of loratadine and its metabolites in young children.

Anti-Allergic Agents↗
PubMed1999

Effect of chloroform, xylene, and halothane on enamel and dentin microhardness of human teeth.

OBJECTIVE: The purpose of this study was to assess in vitro the effect of commonly used gutta-percha solvents on the microhardness of human enamel and dentin. STUDY DESIGN: Crowns of human teeth were cut and treated with chloroform, xylene, and halothane. Treatment consisted of exposing the specimens for 5 or 15 minutes to the test solvents. Acid-treated and saline-treated specimens served as controls. After each treatment period, the specimens were rinsed, dried, and prepared for Vicker's microhardness analysis. Vicker's microhardness values for each specimen were recorded before and after treatment, and the differences were statistically compared. RESULTS: A statistically significant decrease in enamel and dentin microhardness was found in most solvent-treated groups; the amount of the decrease was directly related to the exposure time. CONCLUSIONS: Chloroform, xylene, and halothane may cause a significant softening effect on both enamel and dentin. This softening is already apparent after 5 minutes of treatment.

Adult↗
PubMed1999

A laboratory assessment of enamel hypoplasia of teeth with varying severities of dental fluorosis.

The effect of lifelong exposure to drinking-water containing fluoride on tooth enamel microhardness was investigated. Dental fluorosis of teeth from adult subjects, who lived continuously since birth in areas characterized by the hot climate of India, supplied by drinking-water containing between 0.5 and 8.7 parts/10 F, was estimated by the Dean score. Tooth enamel sections were examined from the enamel surface towards the dentino-enamel junction (DEJ) for microhardness. Separated enamel crowns were pulverized and analysed for fluoride. Regarding the distribution of the fluoride concentrations in the drinking-water, we selected a partition below and above 0.8 parts/10 F as a criterion for comparison between the results. Tooth enamel of humans from Israel living in a drinking-water area containing about 0.5 parts/10 F was also examined. Positive associations were evident between fluoride in drinking-water, fluoride concentrations in the bulk enamel and fluorosis selection. A significantly high inverse relationship was evident between the fluoride concentration of the drinking-water and the subsurface enamel microhardness. In similar fluoride-concentration drinking-water areas of India and Israel the microhardness of the subsurface enamel was less for the Indian teeth. The microhardness of the enamel near the DEJ for the three different water fluoride-concentration areas was not significantly different.

Adult↗
PubMed1990

Proposal and application of an ecotoxicity biotest based on Escherichia coli.

The authors propose the use of an ecotoxicity biotest based on Escherichia coli for the sanitary control of water. The sensitivity of the proposed model was evaluated using a group of representative toxicants, and its response (synergism, additive or antagonism) to toxicants was observed. Finally, the biotest was applied to 124 water samples from rivers, underground sources, drinking water and wastewater. The results of the biotest were compared with the sanitary classification of the waters.

Cell Division↗
PubMed1990

Acoustic emission from trabecular bone during mechanical testing: the effect of osteoporosis and osteoarthritis.

This study examines the relation between the nature of acoustic emission signals emitted from cancellous bone under compression and the mechanical properties of the tissue. The examined bone specimens were taken from 12 normal, 31 osteoporotic and six osteoarthritic femoral heads. The mechanical behaviour of the osteoporotic bone specimens was found to be significantly different from that of the normal specimens both in the pre-yield and post-yield ranges. In the osteoarthritic bones only the elastic behaviour was significantly different. The rates of acoustic events before yield and beyond it were found to be significantly higher both in the osteoporotic and osteoarthritic bone specimens. The average peak amplitude of the signals was also significantly higher in the diseased bones. Stepwise regression analysis showed that a combination of the acoustic emission parameters could significantly predict some mechanical properties of the bone. The energy absorbed during compression and the ultimate compressive stress of the specimens could be estimated from the rate of pre-yield acoustic events, the average amplitude of the signals and the rate of post-yield events. However, the explanation power of the acoustic emission parameters was only moderate. The nature of acoustic emission signals was thus demonstrated to be a potential tool for assessing bone quality.

Acoustics↗
PubMed1988

Effects of loratadine (SCH 29851) in suppression of histamine-induced skin wheals.

The efficacy and safety of single oral doses (10, 20, 40, and 80 mg) of loratadine (SCH 29851) in suppressing formation of histamine-induced wheals were assessed in a crossover study in 29 healthy male subjects. One hour prior to dosing and 1, 2, 3, 4, 6, 8, 12, 16, 24, 28, 32, 36, 40, and 48 hours after dosing, histamine and saline were injected intradermally into opposite arms. Measurements of resulting wheal areas showed loratadine suppressed wheal formation significantly better than placebo; suppression was dose related. The mean suppression over 48 hours was 16% in placebo-treated subjects and 35%, 45%, 51%, and 67% in the 10, 20, 40, and 80 mg loratadine-treated subjects, respectively. The onset of action occurred within the first hour. Duration of suppression was dose related, ranging from 12 hours with the lowest dose (10 mg) to 48 hours with the higher doses (40 and 80 mg). Incidence of sedation and other side effects were comparable among all doses of loratadine and placebo.

Adolescent↗
PubMed1981

The interaction of calcium transport and ADP phosphorylation in brain mitochondria.

Brain mitochondria respiring on glutamate plus malate had a respiratory control index (RCI) for the addition of ADP of 5.5 and P:O ratio of 2.9. These mitochondria also had a Ca2+:O ratio of approximately 5.2, and the ratio of oxygen uptake in the presence of external Ca2+ to that in its absence was 4.0. The reversible transition of respiration to State 3 on the addition of ADP in phosphate media could be blocked by the prior accumulation of 50--200 nmoles/mg of Ca2+. The inhibition was reversible, and on the release of the accumulated Ca2+ by Na+/Ca2+ exchange, the mitochondria became responsive to ADP. The decreased response to ADP following the addition of Ca2+ is probably associated with Ca2+ ions complexing adenine nucleotides within the mitochondria, thus reducing the exchangeable pool and the amount of ADP available to the F1-ATPase.

Adenosine Diphosphate↗
PubMed1979

Regulation of Ca2+ efflux from kidney and liver mitochondria by unsaturated fatty acids and Na+ ions.

The effects of fatty acids and monovalent cations on the Ca2+ efflux from isolated liver and kidney mitochondria were investigated by means of electrode techniques. It was shown that unsaturated fatty acids and saturated fatty acids of medium chain length (C12 and C14) induced a Ca2+ efflux from mitochondria which was not inhibited by ruthenium red, but was specifically inhibited by Na+ and Li+. The Ca2+-releasing activity of unsaturated fatty acids did not correlate with their uncoupling activity. In kidney mitochondria a spontaneous, temperature-dependent Ca2+ efflux was observed which was inhibited either by albumin or by Na+. It is suggested that the net Ca2+ accumulation by mitochondria depends on the operation of independent pump and leak pathways. The pump is driven by the membrane potential and can be inhibited by ruthenium red, the leak depends on the presence of unsaturated fatty acids and is inhibited by Na+ and Li+. It is suggested that the unsaturated fatty acids produced by mitochondrial phospholipase A2 can be essential in the regulation of the Ca2+ retention in and the Ca2+ release from the mitochondria.

Animals↗