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At least 235 records · Page 13Linked to original sources
PubMed1991

Development of epidemiological method for the Helicobacter pylori by polymerase chain reaction.

The polymerase chain reaction was used to develop a method for the detection of Helicobacter pylori, a causative agent of gastritis, as well as for the elucidation of its mode of transmission. A genomic library of Helicobacter pylori DNA in Escherichia coli JM109 was constructed by cloning Hind III-digested DNA fragments into plasmid vector pUC18. The nucleotide sequences from seven recombinant clones were determined and five sets of oligonucleotide primers were synthesized on the basis of the sequences from five clones (B4, B9, B10, C15 and I22). The PCR amplifications with these primers were performed using DNA samples from five strains of Helicobacter pylori, two Campylobacter spp. and eleven species of enteric bacteria. Amplifications of the target DNA fragments in all of 5 strains of Helicobacter pylori were observed from the PCR with primers derived from clone B4, B9, C15 and I22. When the specificity was checked with the DNA samples from 13 other bacteria as template DNA for the PCR, specific amplification that produced the correct size of the target DNA of Helicobacter pylori was shown only in the PCR with primers derived from clone B9 and C15. The detection limit in the PCR amplification, determined by the heat-lysis method, was 500 cells of Helicobacter pylori.

Base Sequence↗
PubMed1986

[Epidemiologic methods of estimation of a secondary cancer associated with cancer treatment].

It is a prerequisite to define "secondary cancer associated with cancer treatment" before estimating it statistically. There are 4 major statistical methods for estimating secondary cancer associated with cancer treatment. Method A: Individually calculate a person-year and multiply it by the cancer incidence rate to obtain the expected number of secondary cancers. Then, compare this with the observed number. Method B: Estimate a person-year by multiplying the survival rate for the same type of cancer by the number of cancer patients. Then, calculate the expected number of secondary cancers as in Method A and compare the result with the observed number. Method C: Compare the proportions of site-specific cancer incidence in the study group with those of the control group. Method D: Compare the incidence rates of secondary cancer in two treatment groups in a randomized trial or in well matched groups. Method A is considered to be the best method, but it is necessary to use the best matched cancer incidence rate in estimating the expected number of secondary cancers. In evaluating the causal relationship it is necessary to take into account both biological significance and statistical significance.

Humans↗
PubMed1979

[Study of 357 cases of phlebitis of the lower extremities in 2 inter-regional samplings. I. Methods, epidemiological data and analysis of etiopathogenetic elements].

Using a specially designed record card, 357 cases of superficial and deep thrombophlebitis and phlebothrombosis of the lower extremities have been investigated. Of these 261 were observed in Piedmont and 96 in the Trentino region. A comparative study of aetiopathogenetic data in the two regions was made possible by means of punched cards and subsequent computer processing. The study was completed by statistical analysis. Apart from the region of birth and residence, sex (prevalently female) and age which in both samples mainly affects subjects aged between 30 and 45, the type of working activity was considered in relation to sex and age, frequency of absenteeism (higher in Piedmont), family history of venous disease, incidence of orthostatism, the use of contraceptive pills, the period in which the first clinical signs occurred with considerable diversity between the two regions, traumas (more frequent in Piedmont) and the incidence of the different causes which was vastly different in the two samples, were assessed. On the basis of the comparative data obtained, an interpretation of the real significance of the results is attempted, reference also being made to the type of population under examination, the Piedmontese being considered of mixed strain and the Trentino pure.

Adolescent↗