1,721,119 research outputs found
POSSIBLE IDENTITY OF TRANSCRIPTION AND TRANSLATION SIGNALS IN EARLY VITAL SYSTEMS
No full textThe distribution of codons was analysed in three classes of eukaryote proteins having widely different evolutionary rates: 78 histones, 40 tubulins, and seven fibrinogens. In this set of genes, (i) it was confirmed that codons which are components of known transcription signals, like ATA, are used infrequently when a synonym is available, particularly in the more constrained proteins, and (ii) it was observed that the three codons which have an iso-accepting transfer with anticodon UAA, UAG or UGA are also suppressed. Then, the distribution of UAA, UAG and UGA trimers was studied in 498 tDNAs and 198 rDNAs. It was found that these trimers are weakly but significantly suppressed in tDNAs and to a lesser extent in rDNAs. It was advanced that the present suppression of ATA, which codes for Methionine in several mitochondria, and of the TAA, TAG and TGA trimers in tDNAs, might be an indication that at the very early stages of the evolution of translation and transcription the signals for initiation and termination were shared by the two processes
Epidemiology of infant deaths due to congenital malformations: Italy 1958-1981
No full textThe spatial and temporal distribution of infant death rates attributed to the single cause of congenital malformation (DCM) in Italy was studied for the period 1958-1981. Variation of DCM rates in this period was investigated for the whole country, for the three main geographical areas of the North, Center, and South, and for each of the 18 Italian regions (there are 20 administrative regions, but in this study Abruzzo were pooled with Molise and the Aosta Valley with neighbouring Piedmont). It was found that DCM decreases significantly with time. The decrease is considerable in the North and the Center of the country, whereas in the South temporal variation is minimal. There is a marked decrease of the variance of the DCM rates between regions with later years, possibly indicating a tendency to equalization of environmental effects in a large part of the peninsula
Amino acid and codon use: in two influenza viruses and three hosts [Utilisation de codons et d'acides aminés : chez deux virus de la grippe et chez trois hotes]
No full textOBJECTIVE: The aim of this study was to compare the use of amino acids and codons in influenza viruses A and B and in their common hosts, to highlight any relevant difference. METHODS: The frequency of the 20 amino acids and of the 61 codons was studied in influenza viruses A, B, and in man, pig, and chicken. The correlation in amino acid and codon use among these hosts was calculated. RESULTS: The correlation between the frequency of the 20 amino acids and the molecular weight was also calculated and it was very similar in all studied hosts, ranging from 0.506 to 0.595. The correlation of codon frequency among these organisms was highest between man and chicken (r=0.974), and lowest between pig and virus B (r=0.147). CONCLUSIONS: The important correlation in codon use among the three hosts and the two viruses suggests there was a remote lateral gene transfer among the three hosts and the two viruses. The higher use of alanine, leucine, and proline in man versus virus A is significan
ENRICHMENT OF OLIGONUCLEOTIDE SETS WITH TRANSCRIPTION CONTROL SIGNALS .3. DNA FROM NONMAMMALIAN VERTEBRATES
No full textWe studied the frequency distribution of 1,048,576 oligonucleotides 10 bp long in a sample of 1.072 x 10(6) bases of genes from non-mammalian vertebrates, made of 322 sequences extracted from EMBL(R) 29.0, with the aim of detecting transcription control signals. Among all decamers, 2097 (0.2%) had a frequency 10 times higher than the mean and were subjected to further statistical analysis. For each of the 2097 decamers (parents), we counted the individual frequencies of the 30 decamers differing from the parent by one base mutation (progeny) and we calculated two variance/mean chi squares for the progeny, with and without the parent decamer. By studying the distribution of the ratio between the two chi squares we observed that out of 2097 decamers that occurred > 10 times more frequently than average, 1017 had a chi square ratio of between 1 and 1.5; in this final set, which corresponds to < 0.097% of all possible decamers, 75 decamers were found to contain 100 transcription control elements, like CCAAT and others. The final set contains a high excess of signals when compared to 100 random sets of 1017 decamers. Some of the decamers selected with the procedure are members of consensus sequences rather than unique sequences
Sociomedical indicators in the cholera epidemic in Ferrara of 1855
No full textThe historical report on the cholera epidemic of 1855, conserved in Ferrara City's archives allowed us to verify the probable relation between the environment and epidemic in a broad sense, using log-linear analysis and multiple logistic regression. Two thousand and thirty-three cases were analyzed and the quantitative/qualitative variables available from the report were analyzed in relationship with mortality and morbidity rates, considered as response variables. From the analysis of the quantitative variables, it emerges that the variables having a significant influence on the morbidity/mortality rates are the number of individuals and the average number of inhabitants per house. From the analysis of the qualitative variables, it emerges that all the descriptive variables of the state of the streets and houses express a strong association with mortality and morbidity. With the present analysis, data available--a detailed 'street by street' morbidity and mortality recording from cholera in 1855 in Ferrara--were analyzed with modern means and the overall picture that emerge is that in the better kept houses in the better parts of the town had less cholera morbidity and especially mortality
Impaired healing response of periodontal furcation defects following flap debridement surgery in smokers - A controlled clinical trial
No full textOBJECTIVES: The purpose of the present parallel-design, controlled clinical trial was to evaluate the treatment outcome of periodontal furcation defects following flap debridement surgery (FDS) procedure in cigarette smokers compared to non-smokers. MATERIALS AND METHODS: After initial therapy, 31 systemically healthy subjects with moderate to advanced periodontitis, who presented at least one Class I or II molar furcation defect, were selected. Nineteen patients (mean age: 40.3 years, 15 males) were smokers (>or=10 cigarettes/day) and 12 patients (mean age: 44.8 years, 3 males) were non-smokers. Full-mouth plaque score (FMPS) and full-mouth bleeding score (FMBS), probing pocket depth (PPD), vertical clinical attachment level (v-CAL), and horizontal clinical attachment level (h-CAL) were assessed immediately before and 6 months following surgery. RESULTS: Overall, statistically significant v-CAL gain was observed in smokers (1.0 +/- 1.3 mm) and non-smokers (1.3+/-1.1 mm), the difference between groups being statistically significant (p=0.0003). In proximal furcation defects, v-CAL gain amounted to 2.3+/-0.7 mm in non-smokers as compared to 1.0+/-1.1 mm in smokers (p=0.0013). At 6 months postsurgery, non-smokers presented a greater h-CAL gain (1.3+/-1.1 mm) than smokers (0.6+/-1.0 mm), with a statistically significant difference between groups (p=0.0089). This trend was confirmed in both facial/lingual (1.4+/-1.0 versus 0.8+/-0.8 mm) and proximal furcation defects (1.2+/-1.3 versus 0.5+/-1.2 mm). The proportion of Class II furcations showing improvement to postsurgery Class I was 27.6% in smokers and 38.5% in non-smokers. After 6 months, 3.4% of presurgery Class I furcation defects in smokers showed complete closure, as compared to 27.8% in non-smokers. CONCLUSIONS: The results of the present study indicated that (1) FDS produced clinically and statistically significant PPD reduction, v-CAL gain, and h-CAL gain in Class I/II molar furcation defects, and (2) cigarette smokers exhibited a less favorable healing outcome following surgery in terms of both v-CAL and h-CAL gain
IDENTIFICATION OF A SET OF FREQUENT DECANUCLEOTIDES IN PLANTS AND IN ANIMALS
No full textWe studied the frequency distribution of 1,048,576 oligonucleotides 10 bp long in a sample of 1.961 Mbase of genes from plants, made of 635 sequences extracted from GenBank 71.0, with the aim of detecting transcription control signals. Among all decamers, 3255, or 0.3%, had a frequency 10 times higher than the mean and were subjected to further statistical analysis. For each of the 3255 decamers (parents), we counted the individual frequencies of the 30 decamers (progeny) differing from the parent by one base mutation, and calculated two variance/mean chi-squares for the progeny, with and without the parent decamer. By studying the distribution of the ratio between the two chi-squares we observed that out of 3255 decamers > 10 times frequent than average, 432 had a chi-square ratio > 1.9. In this residual set, which corresponds to < 0.04 per cent of all possible decamers, only 15 known eukaryotic transcription control elements were found; on the other hand, it included 29 decanucleotides that matched with decanucleotides of a set of Drosophila, 24 with a set from mammals, 13 with a set from yeast and four with a set of viruses--all sets identified with the statistical procedures here described. These decanucloetides are highly repetitive and seem to be present throughout all higher organisms, whereas they are uncommon in mammalian viruses
Frequencies of codons in histones, tubulins and fibrinogen: Bias due to interference between transcription signals and protein function
No full textThe distribution of codons was studied in 65 proteins: 48 histones, 14 tubulins, and three fibrinogens, With the methodology used, (1) we confirmed that the preterminator state of a codon has no detectable effect on codon bias. (2) The well-known effect of CG suppression was visible. We also found that (3) some codons which are very rare, are equal to parts of known transcription signals. Thus, we advanced that to avoid signal interference, the use of these codons is suppressed when a synonymous codon is available. In addition we found that in the whole series of codons, transcription signals are less frequent than in a random sequence of equal composition. Finally we observed (4) that tryptophan is absent in histones. This absence was related not to the TGG codon itself, but to characteristics of the amino acid. We conclude that the functional constraints of a protein can influence, at least for synonymous codon usage, the evolution of its own coding sequence
Clinical effect of subgingival tetracycline irrigation and tetracycline-loaded fiber application in the treatment of adult periodontitis
No full textA controlled clinical trial was carried out to compare the clinical effect of combined antimicrobial-mechanical treatment modalities on moderate-to-deep periodontal pockets in patients with adult periodontitis. Twelve patients having at least three nonadjacent sites of periodontitis were included in the split-mouth study. Gingival Index, Plaque Record, bleeding on probing, probing depth, attachment level, and recession depth were recorded immediately before treatment. In the control site, supragingival and subgingival scaling was performed with an ultrasonic scaler. One experimental site received supplemental irrigation with 15 mL of a 100-mg/mL tetracycline solution, while the other received a tetracycline-loaded fiber after mechanical instrumentation. Fibers were left in place for 10 days. Reevaluation 30 and 60 days after treatment showed that all three treatment modalities were effective in improving clinical parameters. No adjunctive effect on the healing response was obtained by augmenting mechanical debridement with tetracycline
Studio epidemiologico retrospettivo dei tumori della cavità orale,esofago, fegato: Italia (1958-1985)
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