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Saxitoxin and neosaxitoxin are potent neurotoxins that can cause paralytic shellfish poisoning when consumed. A new assay is presented here to quantify saxitoxin (STX) and neosaxitoxin (NEO) in human urine samples. Sample preparation of 500-microL samples included the use of weak-cation-exchange solid-phase extraction in a multiplexed 96-well format. Extracts were preconcentrated and analyzed via 10-min hydrophilic interaction liquid chromatography followed by electrospray ionization. Protonated molecular ions were quantified via multiple reaction monitoring mode in a Qtrap mass spectrometer. The method uses novel 15N7-isotopically enriched STX and NEO internal standards. Method validation included the characterization of two enriched urine pools. The lowest reportable limits for STX and NEO were 4.80 and 10.1 ng/mL, respectively, using both quantification and confirmation ions. These two toxins were not detected in a reference range of humans who consumed seafood in the preceding 72 h, suggesting that few false positives would occur when trying to identify people exposed to STX or NEO.

SummaryAn animal model of maternal-newborn transmission of group B streptococci (GBS) was developed. Pregnant Swiss-Webster mice were colonized by applying 10' GBS to the oral cavity, vagina, and nipples daily for 3 days before delivery. Lipoteichoic acid (LTA) from type 111 GBS or phosphate buffered saline was applied topically to the oral cavity, perineum or nape of newborn mice.Cultures of newborn mice at 3 days of age revealed 35 of 75 (47%) controls and 0 of 79 animals given 2 doses of LTA (2 mg/ ml) were positive for GBS at one or more sites. One to two% of control and LTA-treated mice remained culture positive at 7 days of age. None developed GBS disease and no obvious toxicity was noted. This is the first in vivo evidence that colonization with GBS can be prevented by interfering with their adherence to epithelial surfaces.LTA also prevented colonization by 60,000 GBS in the oral cavity of 1-day-old newborn mice. A minimum concentration of 0.5 mg LTA/ml was required and similar dose response curves were obtained in preventing maternal-newborn transmission or oral newborn colonization. LTA from type I11 GBS also protected against types Ia and 11. Only 6 of 15 (40%) vaginally colonized, nonpregnant mice became noncolonized 3 days after LTA treatment. SpeculationTopically applied lipoteichoic acid from group B streptococci may be a useful method of preventing GBS colonization and/or disease in human infants at birth if it is nontoxic. The method avoids the problems associated with antibiotic prophylaxis and vaccine development.Group B streptococci (GBS) are a significant cause of neonatal morbidity and mortality. Early onset disease, characterized by sepsis and meningitis, is the more common type and is acquired from the ano-genital tract of the mother at birth (3, 4). Attempts at antibiotic prophylaxis in newborn infants (14, 17) and pregnant women (19) have met with varied success and further study is needed. Development of a vaccine for antibody deficient mothers will be difficult and time-consuming (4). Development of alternate methods of prophylaxis are needed.In 1975, Beachey (6) showed that lipoteichoic acid (LTA) in the cell wall of group A streptococci was responsible for binding of these organisms to oral mucosal cells in vitro. Pretreatment of oral epithelial cells with purified LTA inhibited 78% of added streptococci from binding. In 1977, Ofek et al. (12) showed that LTA from group A streptococci inhibited group B streptococcal binding --to the same degree.Topical application of LTA to a mucosal surface at birth could potentially prevent or reduce colonization with GBS. This method would avoid the disadvantages of antibiotic prophylaxis and some of the difficulties in vaccine development. Because the method has not been tested in vivo, an animal model of maternal-newborn transmission of GBS was developed. MATERIALS AND METHODSOrganisms. Prototype strains type I a (SS-615) and type I1 (SS-619) and wild strain type 111 (DS-2434-80), beta-hemolytic group B streptococci were supplied by Richard Fa...

Percutaneous transthoracic needle aspiration was performed on 228 occasions to obtain lung specimens from 202 patients with suspected Pneumocystis carinii pneumonitis. In 121 patients the diagnosis was established by identifying P carinii organisms in lung aspirates. Six patients whose aspirates did not contain P carinii were found to have the organism at autopsy. Findings from toluidine blue O and Gomori methenamine silver nitrate stains were equally satisfactory for detecting P carinii, but the percentage of specific diagnosis was higher when specimens were stained with both. Pneumothorax that required a thoracotomy tube occurred in 39 patients. Other infectious agents, either bacteria or fungi, were found in only four patients. Percutaneous pulmonary needle aspiration--when performed under fluoroscopic guidance--is a rapid and effective method for the diagnosis of P carinii pneumonitis.