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Detection of mutA genes in transmitted strains and nontransmitted strains of mutans streptococci.

Our aim was to determine whether an isolate carrying one of the mutA genes was related to its ability to be transmitted from mother to her child. First, 200 mutans streptococci isolates were genotyped by arbitrarily primed polymerase chain reaction (AP-PCR) to demonstrate transmission between 20 mother-child pairs and to detect the transmitted and nontransmitted strains. Then the mutacin structural genes mutA encoding mutacin types I, II, and III were screened by PCR. The results showed that all strains found to carry the mutAI gene were nontransmitted strains; PCR screening primers mutAII and mutAIII did not yield amplicons in any of the strains tested. Our data suggest that an isolate carrying the mutAI gene is related to reduced transmission. The low frequency of detection of mutAII, and mutAIII suggests that there is a high heterogeneity in the genetic determinants needed for the production of mutacin-like substances.

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A case control study of nutritional factors and cervical dysplasia.

The association of nutritional factors with cervical dysplasia was examined through a case-control study. Analysis was conducted in 257 cases and 133 controls confirmed both by cytological examination and colposcopic findings. A 24-h dietary recall questionnaire was used to assess nutritional intake. Various risk factors (including age at first intercourse, number of sexual partners, parity, cigarette smoking, oral contraceptive use, human papillomavirus type 16 infection, and age and race) were adjusted for their potential confounding effects. While analyses were also performed to adjust for total calories, results were not changed significantly. Among the nutrients examined, vitamin A intake showed a significantly increased risk at the lowest quartile compared to the highest quartile, with an odds ratio of 2.2 (95% confidence interval, 1.2-4.2). A significant trend of increasing risk was also observed with lower intake of vitamin A (P = 0.05). Riboflavin showed increased risk at the two lower quartiles of intake with a trend test P value of 0.04. Increased risk was also found for lower intakes of vitamin C compared to the highest intake level. For folate, increased risk was found in the second highest quartile compared with the highest quartile with an odds ratio of 2.0 (95% confidence interval, 1.0-3.8). The calcium:phosphorus ratio showed an increased risk at the lowest level (odds ratio, 2.0; 95% confidence interval, 1.0-4.3). Insufficient intake of vitamin A, riboflavin, ascorbate, and folate is associated with an increased risk of cervical dysplasia.

Adult↗