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At least 55 records · Page 3Linked to original sources
PubMed1976

Is Hodgkin's disease infectious? Discussion of an epidemiologic method used to impute that it is.

A method proposed by MacMahon for the differentiation between familial and environmental causes for disease has recently been applied to demonstrate an environmental etiology for Hodgkin's disease. It is shown that the method, which depends on the comparison of time-of-onset differences with age-at-onset differences for familial pairs with disease, is biased toward results suggestive of an environmental etiology when applied to data of the kind typically analyzed--data restricted to instances in which both members of a familial pair develop disease in a specified, limited time interval. Other features of such data are discussed.

Age Factors↗
PubMed1990

Epidemiological methods to study the interaction between HIV infection and other sexually transmitted diseases.

Numerous studies performed over the past 5 years have indicated an association between HIV infection and other sexually transmitted diseases (STDs), particularly those involving genital ulceration. Such an association may be causal, indicating that STDs increase susceptibility to, or infectivity of, HIV infection or may result, in whole or in part, from the mutual dependence of HIV and STDs on patterns of sexual activity, or from an effect of HIV infection on the clinical course of STDs. In this paper we discuss the issues arising in the design and analysis of studies conducted to investigate this association. A numerical illustration is used to demonstrate non-causal associations that may arise in observational studies due to confounding and misclassification. Published cross-sectional and longitudinal studies are reviewed, and recommendations made for future studies. Special emphasis is given to the use of randomized intervention trials to overcome many of the biases associated with observational studies, and to provide information on the efficacy of intensive STD treatment programmes in reducing the transmission of HIV.

Cross-Sectional Studies↗
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↗
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↗
PubMed1990

Analysis of clinical and food-borne isolates of Listeria monocytogenes in the United States by multilocus enzyme electrophoresis and application of the method to epidemiologic investigations.

To investigate the microbiology and epidemiology of the 1,700 sporadic cases of listeriosis that occur annually in the United States, we developed a multilocus enzyme electrophoresis (MEE) typing system for Listeria monocytogenes. We studied 390 isolates by MEE. Eighty-two electrophoretic types (ETs) were defined. Two distinct clusters of ETs, ET group A (ETGA) and ET group B (ETGB), separated at a genetic distance of 0.440, were identified. Strains of ETGB were associated with perinatal listeriosis (P = 0.03). All strains of H antigen type a were in ETGA, while all strains of H antigen type b were in ETGB. Among 328 clinical isolates from cases of literiosis, 55 ETs of L. monocytogenes were defined. Thirty-four ETs were identified among 62 isolates from food products. The mean number of strains per ET (5.2) was significantly higher among clinical isolates than among food-borne isolates. Examination of isolates from outbreaks further documented the link between cases and contaminated food products. In one investigation, we found 11 different ETs, ruling out a single common source as a cause of that outbreak. By examining a large number of isolates collected over a specified time in diverse geographic locations in the United States, we have begun to establish a baseline for the study of the epidemiology of listeriosis by MEE.

Bacterial Typing Techniques↗
PubMed1976

[Use of a computer and mathematical methods in epidemiological work. Report 3. Experience with the operational tracing of infectious morbidity using an automic self-service information unit].

The authors describe their experience in the elaboration and introduction into practice of epidemiological service of the system of operative tracing of infectious morbidity at the level of the central sanitary-epidemiological station under conditions of automatic control system. Data on improvement of information supply and logic analysis of the information with the aid of Minsk-22 computer are presented. Forms of documents are considered. Experience in the use of this system for two years pointed to its expediency.

Communicable Diseases↗