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Biomedical subjects

K M Stone

Publications and source records attributed to K M Stone.

24 records · Page 2Linked to original sources

Legionella in cooling towers.

Legionellosis (Legionnaires' disease and Pontiac fever) outbreaks have been associated with aerosols ejected from contaminated cooling towers--wet-type heat rejection units (WTHRUs) used to dissipate unwanted heat into the atmosphere. The Vermont Department of Health undertook a program to inventory, inspect, and sample all WTHRUs in Vermont from April 1981 to April 1982. All WTHRUs were sampled for Legionella pneumophila and data were obtained for location, design, construction, and operating characteristics. Of the 184 WTHRUs operating, statistical analyses were performed on those 130 which were sampled for L. pneumophila only once during the study period. Of these, 11 (8.5%) were positive for L. pneumophila. Sources of makeup water and period of operation had significant association with the recovery of L. pneumophila. Five out of 92 towers (5.4%) utilizing surface water sources for cooling were positive for L. pneumophila, in contrast to 6 positive towers of the 38 units (15.8%) which obtained makeup water from ground water sources (p = .054 by chi-square test). Nearly 15% of the 54 units which operated throughout the year were positive, compared to less than 4% of the 76 towers operating seasonally (p = .03 by chi-square test). The mean pH of the cooling water in units where L. pneumophila was recovered (8.3) was significantly higher than the mean pH of 7.9 in units testing negative (p less than .05 by t-test). In addition, the mean log-transformed turbidity of positive towers, 0.03 nephelometric units (ntu), was significantly lower than the mean of log turbidity of negative towers, 0.69 ntu (p less than .02 by t-test).

Air Conditioning↗

Family planning, sexually transmitted diseases and contraceptive choice: a literature update--Part I.

Couples who use contraceptives not only protect themselves against unwanted pregnancies, but also may reduce their risk of becoming infected with a sexually transmitted disease (STD). No currently available method, however, is highly effective in protecting simultaneously against pregnancy and infection. Thus, couples who place high priority on minimizing both risks may have to use two methods. The need for contraceptive methods that provide effective protection against both pregnancy and STDs has been intensified by the HIV epidemic, but progress has been slowed by the lack of integration between the STD and family planning fields. The first part of this two-part article discusses the similarities and differences between the two fields, examines the impact of STDs on contraceptive use and services, and reviews the scientific literature dealing with the effects of condoms, spermicides and barrier-and-spermicide methods on the risk of STD transmission. Part II (which will appear in the next issue) examines what is known about the effects of oral contraceptives, the IUD, tubal sterilization and abortion on reproductive tract infections. The second part also includes a discussion of the trade-offs involved in choosing a contraceptive and presents estimates of the first-year rates of unplanned pregnancy and gonorrhea infection (given an infected partner) that would occur among women using various contraceptive methods.

Contraceptive Devices, Female↗

Establishment of an exposure level to tetrachloroethylene in ambient air in Vermont.

Where environmental contaminants pose potential health hazards, health departments are involved in complex and often controversial situations. Often the rapid formation of a threshold exposure level is required to protect public health. A decision making process was implemented in Vermont when it became necessary to have an interim ambient air exposure level to test for tetrachloroethylene contamination in the water, air, and soil of a community. Contamination of public and private drinking water and ambient air in schools and homes was discovered as a result of uncontrolled waste disposal from an industrial uniform laundry and drycleaning plant. A telephone survey was conducted to determine action taken by the other 49 States regarding emission standards for tetrachloroethylene into ambient air. There were no guidelines in 25 States, and there were guidelines in the remaining 25. Vermont's Commissioner of Health convened a multidisciplinary group of public health professionals to review various approaches to the establishment of an ambient air standard. A decision making action using modified Delphi and nominal group consensus methods set the interim standard at 67 micrograms per cubic meter in ambient air. The drycleaning plant had been closed voluntarily before the standard was established, and the interim standard was used to prevent reopening of the plant through a health order issued by the Vermont Health Department. The standard was also useful for guidance during environmental remediation.

Air Pollutants↗

Development of sexually transmitted diseases treatment guidelines, 1993. New methods, recommendations, and research priorities. STD Treatment Guidelines Project Team and Consultants.

To develop the 1993 Sexually Transmitted Diseases Treatment Guidelines, experts from the Centers for Disease Control and Prevention reviewed the literature on sexually transmitted disease treatment, assembled tables of evidence, and listed key questions on therapeutic outcome: microbiologic cure, alleviation of symptoms, and prevention of sequelae and transmission. At a meeting with external experts, evidence was systematically assessed and guidelines developed. Quality of evidence for microbiologic cure was generally good for gonorrhea and chlamydia, poor for syphilis, and fair for most other diseases. Evidence on preventing sequelae and transmission was limited. The Guidelines include new recommendations for single-dose oral therapy of gonorrhea (cefixime, ciprofloxacin, and ofloxacin), chlamydia (azithromycin), and chancroid (azithromycin); outpatient therapy of pelvic inflammatory disease (ofloxacin and either clindamycin or metronidazole); and patient-applied therapy of genital warts (podofilox). Syphilis therapy did not change substantially. Several global issues that emerged during the development of the World Health Organization Recommendations for the Management of Sexually Transmitted Diseases also are discussed. This evidence-based approach clarified important treatment issues and the rationale for recommendations, and identified research priorities.

Anti-Infective Agents↗