RESUMEN
Sterilized soil samples (20 g of soil per 50-ml flask), amended with 600 mug of glucose-carbon and 60 mug of NH(4)-N . g of dry soil, were inoculated with bacteria (Pseudomonas paucimobilis) alone or with bacteria and amoebae (Acanthamoeba polyphaga). We used wet-dry treatments, which involved air drying the samples to a moisture content of approximately 2% and remoistening the samples three times during the 83-day experiment. Control treatments were kept moist. In the absence of amoebae, bacterial populations were reduced by the first drying to about 60% of the moist control populations, but the third drying had no such effect. With amoebae present, bacterial numbers were not significantly affected by the dryings. Amoebal grazing reduced bacterial populations to 20 to 25% of the ungrazed bacterial populations in both moisture treatments. Encystment was an efficient survival mechanism for amoebae subjected to wet-dry cycles. The amoebal population was entirely encysted in dry soil, but the total number of amoebae was not affected by the three dryings. Growth efficiencies for amoebae feeding on bacteria were 0.33 and 0.39 for wet-dry and constantly moist treatments, respectively, results that compared well with those previously reported for Acanthamoeba spp.
RESUMEN
In the past several years, a new trend has emerged where women in increasingly growing numbers are becoming hesitant to accept the risks associated with hormonal and invasive methods of birth control. It is as part of this trend that a revival of sorts is occurring with the cervical cap, a form of birth control with roots which precede recorded history and which, in its modern form, was widely advocated in late 19th and early 20th century Europe. Based on the principle of occlusion, the cervical cap appears effective and risk-free, both vital concerns to women of all centuries. Women's health activists and organizations have been in the forefront of this revival. Two of the first organizations to take an active interest in making the cap available were the New Hampshire Feminist Health Center in Concord, New Hampshire, and the Emma Goldman Women's Health Clinic in Iowa City, Iowa. The National Women's Health Network, a national organization based in Washington, D.C., has also been an active advocate on the cervical cap's behalf.
PIP: The historical background of the development and use of cervical caps and recent efforts to revive its popularity were described, and current issues concerning its use were discussed. The cervical cap is generally made of rubber, shaped like a thimble, fitted over the cervix, and held in place by suction. It functions as a mechanical device to prevent sperm from entering the cervix. It is sometimes used in combination with chemical barrier methods. During the 1800s various types of rubber cervical caps were invented and during the 1900s many types of caps, made from either metal, celluloid, or rubber, experienced fluctuating levels of popularity. Cervical caps declined in popularity as acceptance of oral contraceptives and IUDs increased. As this trend continued, fewer caps were manufactured, caps became increasingly difficult to obtain, and fewer medical personnel were trained to provide the method. In response to growing concern over the side effects associated with IUDs and oral contraceptives, many women are expressing a renewed interest in cervical caps. Recently the New Hampshire Feminist Health Center and the Emma Goldman Women's Health Clinic in Iowa City began to fit women with cervical caps. Currently only a few cap sizes are available and as a result a large proportion of women cannot be properly fitted with the device. Current issues center on 1) the length of time the cap can safely be left in place; 2) the type of material from which they should be manufactured; and 3) whether a spermicide should be used with the device. Failure rates and contraindications were also discussed. The device is not currently approved by the Food and Drug Administration and since caps are a low profit item the drug industry will not expend money for the clinical testing of the device. Recently the National Institute of Health made funds available for clinic testing. The cultural acceptability of the device and physician attitudes toward the device were also discussed. Several researchers are attempting to develop improved cervical caps.