A novel method for the concentration of Cryptosporidium oocysts from water has been developed, based upon the precipitation of calcium carbonate. A 10 l water sample is treated by adding solutions of calcium chloride and sodium bicarbonate and raising the pH value to 10 with sodium hydroxide. Crystals of calcium carbonate form and enmesh particles in the Cryptosporidium oocyst size range. The crystals are allowed to settle, the supernatant fluid is discarded and the calcium carbonate precipitate dissolved in sulphamic acid. The sample can be concentrated further by centrifugation. Recoveries of oocysts from seeded samples of deionized, tap and river water were in excess of 68%.

AbetractSixty patients with malignancy were enrolled in a study of high dose chemotherapy and peripheral blood stem cell transplantation (PBSW. Stem cells were haxvested prior to PBSCT using 75 cycles of high-dose Cyclophosphamide (Cy) mobilization (4 or 7 G/m2) with collection of a median of 4.6 x lo8/@ mononuclear cells (MNC) (range 0.2 -9.5) and 21.6 x 104/kg colony forming unitgranulocyte /macrophage (CFU-CM) (range 0.1 -220). Forty seven patients were mobilized once, 1 1 required 2 cycles and 2 required 3 cycles. Eight patients (13%) fafled to reach the optimim CFU-GM target (total of > 15 x lo4 CFU-CM/kg) following Cy mobilization. In a multivariate regression analysis. a number of factors identified those patients who were likely to achieve optimum stem cell collections. These included the use of the higher Cy mobilization dose (P

A flow cytometric method for the routine analysis of environmental water samples for the presence of Cryptosporidium oocysts has been developed. It uses a Coulter Epics Elite flow cytometer to examine water samples and to separate oocysts from contaminating debris by cell sorting. The sorted particles are then rapidly screened by microscopy. The method has been evaluated and compared with direct epifluorescence microscopy on 325 river, reservoir and drinking water samples. The technique was found to be more sensitive, faster and easier to perform than conventional epifluorescent microscopy for the routine examination of water samples for Cryptosporidium.

Methods for the simultaneous detection of Cryptosporidium parvum oocysts and Giardia cysts from water are described and their relative recovery efficiencies are assessed for seeded samples of both tap and river water. Cartridge filtration, membrane filtration, and calcium carbonate flocculation were evaluated, and steps to optimize the concentration procedures were undertaken. Increasing centrifugation to 5,000 ؋ g, coupled with staining in suspension, was found to increase the overall efficiency of recovery of both cysts and oocysts. Cartridge filtration for both cysts and oocysts was examined by use of 100-liter volumes of both tap and river water. Improvements in recovery were observed for Cryptosporidium oocysts after extra washes of the filters. Calcium carbonate flocculation gave the maximum recovery for both Cryptosporidium oocysts and Giardia cysts and for both water types. A variety of 142-mm membranes was examined by use of 10-liter seeded samples of tap and river water. Cellulose acetate with a 1.2-m pore size provided the best results for Cryptosporidium oocysts, and cellulose nitrate with a 3.0-m pore size did so for Giardia cysts.

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