Publications by authors named "Zierdt C"

An enzyme-linked immunosorbent assay was devised in order to search for antibodies against Blastocystis hominis in infected humans. Reaction proteins were obtained from washed, axenic B. hominis cells, as sonicate.

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Axenic strains of Blastocystis hominis incorporated 32P, added to the medium as orthophosphate, into a number of phospholipids, including sphingomyelin, cardiolipin, phosphatidic acid, the phosphoglycerides of choline, ethanolamine, serine, and inositol and some other minor phospholipids. Radioactive palmitate and glycerol provided in the growth medium introduced radiolabel into diacylglycerols, triacylglycerols, and all major phosphoglycerides found in the organism. Palmitate is a major fatty acid of cholesterol esters in B.

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Three polyclonal mouse antisera, to Encephalitozoon cuniculi, Nosema algerae, and Nosema corneum, and two polyclonal rabbit antisera, to E. cuniculi and Encephalitozoon hellem, were used in an indirect fluorescent-antibody assay (IFA) with Enterocytozoon bieneusi, E. cuniculi, and Encephalitgozoon.

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1. Six axenic strains of Blastocystis hominis varied in content of lipids from 12 to 43 pg total lipid/cell. With all strains, phospholipid content was about 39% of total lipids.

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alpha-Hemolytic streptococci, variously described as cell-wall deficient (C), L form (L), thiol dependent (O), satelliting (S), pyridoxal dependent (PY), and nutritionally deficient (N), or CLOSPYN, were isolated from patients with endocarditis, brain abscess, subauricular abscess, septicemia, acute and chronic urethritis, recurrent aphthous stomatitis, and fever of undetermined origin. With the aid of satelliting, most of the strains were adapted to grow on a human Mycoplasma growth agar consisting of brain-heart infusion agar fortified with 20% human blood, yeast extract, and arginine. Selected CLOSPYN strains required extensive subculture for only partial reversion to parentallike characteristics.

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For a 13-year period (1978 through 1990), oxacillin-resistant (MIC, greater than 4 micrograms/ml) Staphylococcus aureus (ORSA) strains were collected from Clinical Center (National Institutes of Health) patients and patients from five other U.S. hospitals.

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Blastocystis hominis--past and future.

Clin Microbiol Rev

January 1991

The history of B. hominis is unique. Few infectious agents have provoked the many misconceptions that plague this enigmatic parasitic ameba.

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The in vitro activities of magainin analogs against Blastocystis hominis, Entamoeba histolytica, and Trypanosoma cruzi were assessed by protozoan morphological integrity and motility. The antiprotozoan activities in descending order were magainin B greater than G greater than H, the same order as the alpha-helix contents of the analogs. Magainin B and G were effective against B.

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Staphylococcus aureus bacteriophages (25 phages) were lyophilized in aliquots 12 to 18 years ago and stored in vacuo at -20 degrees C. Eight viruses each lost one log titer, while seventeen retained the original titers. The use of lyophilized phages provided more reproducible phage typing and reduced by 75% the complexity and cost.

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This study was prompted by the paradox of strong presence of mitochondria in an anaerobic protozoan, recently reclassified from the yeasts. Stemming from publication in 1911 to 1912, Blastocystis hominis has been generally accepted as a harmless intestinal yeast of humans, with short standardized textbook (parasitology) descriptions, even to the present day. Reports since 1967 have changed the classification of B.

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For over 50 years, Blastocystis hominis has been held to be a harmless intestinal yeast-probably frequent in stool samples from man and other primates, but usually ignored except as a possible source of confusion with Entamoeba histolytica. More recently, its status as a protozoan parasite has been accepted, and it is now increasingly recognized as an agent of intestinal disease - usually self-limiting but occasionally fatal in monkeys. Here, Charles Zierdt reviews the status o f this intriguing protozoan, drawing attention to its unusual biochemistry.

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Organisms that form an essential extra inner lining of selected areas of the stomach mucosa occur in mice, rats and some other animals. The yeast Cyniclomyces guttulatus (Saccharomycopsis guttulata) was shown in this study to line the stomach of domestic and feral rabbits, guinea pigs, and chinchillas. The layer of yeast cells formed a loose barrier between lumen contents and mucosal surface.

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The acquisition of hospital strains of Staphylococcus aureus by new house officers was studied in an 800-bed referral hospital over a 1-year period. S. aureus isolates, including three strains with characteristic phage patterns that had previously been documented to cause disease in patients and colonize hospital personnel, were recovered from the anterior nares of 35 of 54 newly arrived house officers.

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A blood culture system was developed in which a lysing agent (either Tween 20, one of several other polyoxyethylene adducts, digitonin, or Triton X-100) is added to the blood culture medium. Of 33 Triton compounds, 9 lysed human blood, as did 7 of 21 polyoxyethylene compounds and digitonin, all at a concentration of 0.05%.

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Isolated mitochondria of the anaerobic protozoan Blastocystis hominis were subjected to spectral analysis, color, catalase, and peroxidase tests and found to be completely negative for cytochrome enzymes, catalase, and peroxide. Based on the absence of cytochrome enzymes, the possible evolution of B. hominis mitochondria from anaerobic bacteria is postulated.

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An extraction test for stool occult blood was developed using 3,3', 5,5' tetramethylbenzidine (TMB), which gave reliable results in the presence of interfering substances, such as vitamin C, meat fibers, and vegetable enzymes. The new test was applied to 1,320 fecal specimens from hospitalized patients not on dietary restrictions. Of 189 specimens unequivocally positive by slide tests, 48 were negative by the extraction test, 42 were trace reactions, and 99 were 2+ to 4+.

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The ease with which Mycoplasma hominis can be recovered and the frequency of its occurrence in septicemia may not be fully appreciated. We detected the growth of M. hominis radiometrically with an automated blood culture instrument.

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At Cook County Hospital (Chicago), before 1977, the incidence of endocarditis caused by Pseudomonas aeruginosa was one or two cases per year. The frequency of P. aeruginosa as an etiologic agent of endocarditis among drug abusers increased steadily from five (23%) of 22 patients in 1977 to 15 (68%) of 22 in 1980.

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Evaluation of a commercially available lysis-centrifugation blood culture system (Isolator, DuPont Co., Wilmington, Del.) and a lysis-filtration blood culture system for 3,111 cultures showed that both methods had comparable recoveries (73 and 68%, respectively) of significant aerobic and facultatively anaerobic isolates.

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