Non-mosaic trisomy 16 in a third-trimester fetus.

BACKGROUND: Trisomy 16 in the most common trisomy first-trimester spontaneous abortions, suggesting a high rate of non-disjunction of this chromosome. Deoxyribonucleic acid studies in aborted conceptuses with trisomy 16 have demonstrated a maternal origin in all cases. There have been cases of confined placental mosaicism, fetal mosaicism, and partial trisomy involving chromosome 16 reported in term fetuses. However, to our knowledge, there have been no previous reports of a near-term fetus with full trisomy 16 since the advent of modern chromosomal banding techniques. CASE: A 25-year-old Filipino woman underwent obstetric sonographic evaluation at 32 weeks' gestation; results were remarkable for oligohydramnios, severe growth restriction, and multiple dysmorphic features. Percutaneous umbilical blood sampling was performed for rapid karyotyping, viral serology, and blood profiles. The fetal karyotype was 47, XY+16; the remainder of the laboratory analysis was unremarkable. The patient went into spontaneous labor at 35 weeks' gestation and delivered a stillborn female fetus (birth weight 783 g). Chromosomes from skin, brain, and chorionic villi were examined and all demonstrated trisomy 16 (47, XX,+16). Deoxyribonucleic acid primers for known polymorphic regions of chromosome 16 were used and determined the origin of the extra chromosome to be non-disjunction during paternal meiosis. CONCLUSION: Previously, full trisomy 16 has been thought to be incompatible with fetal survival past the early second trimester. This case also contrasts with previously reported experience with trisomy 16 in that parental origin studies determined that the extra chromosome 16 originated from the father, suggesting that paternal derivation of the additional chromosome may play a role in the ultimate phenotypic expression.

Uterine packing in the combined management of obstetrical hemorrhage.

Uterine packing to control obstetrical hemorrhage has been generally discouraged over the past several decades. Intractable uterine hemorrhage postpartum or following an abortion is an extremely vexing management problem for the physician and continues to be a leading cause of maternal mortality. Uterine packing should be considered as a presurgical management tool after lacerations of the lower genital tract, uterine rupture, or retained products have been ruled out and when conventional therapy fails to control uterine hemorrhage. We describe two obstetrical patients with intractable uterine hemorrhage who were managed with uterine packing in combination with other methods of therapy. Causes of obstetrical hemorrhage and techniques of packing the uterus are discussed.

Excystation of Giardia muris induced by a phosphate-bicarbonate medium: localization of acid phosphatase.

Giardia muris cysts were incubated briefly in an aqueous induction medium of 0.1 M potassium phosphate with 0.1, 0.2, or 0.3 M sodium bicarbonate. High rates of excystation (91.1-96.7%) were recorded within 5 min after the cysts were placed in trypticase-yeast extract-iron-serum (TYI-S) medium. Substitution of phosphate-buffered saline for TYI-S as the excystation medium resulted in high rates (95.9%) of excystation but required an incubation of 15 min. Excystation was inhibited by the presence of 4-4'-diisothiocyanatostilbene-2-2'-disulfonic acid (DIDS), a specific inhibitor of vacuolar and lysosomal acidification. Microscopic observation showed the loss of the peritrophic space and a change in the refractile nature of the cyst wall prior to excystation. Histochemical studies demonstrated a reaction product of acid phosphatase activity in the lysosomelike peripheral vacuoles in induced cysts and in the peritrophic space of cysts placed in excystation medium. Staining with acridine orange suggested that the peripheral vacuoles become acidified during induction. This staining was inhibited also by DIDS. These studies show that in vitro excystation can be produced at high rates by easily prepared media without exogenous enzymes, low pH, reducing agents, or complex components. The data also suggest that excystation may be stimulated by the bicarbonate-phosphate medium accompanied by acidification of the peripheral vacuoles and the release of their contents into the peritrophic space.

Diversity of the parasite assemblage of Fundulus zebrinus in the Platte River of Nebraska.

Changes in the values of the Shannon H' diversity index as determined for individual hosts (infraassemblage diversity), host samples (sample assemblage diversity), and for species density are reported for an assemblage of 7 parasites in Fundulus zebrinus in the Platte River in Nebraska for a 5-yr period. The parasites were: Myxosoma funduli (gill), Trichodina sp. (gill), Gyrodactylus bulbacanthus (gill), Salsuginus sp. (gill), Gyrodactylus stableri (body surface), and Neascus sp. (= Posthodiplostomum; eyes and body cavity). In addition, relative abundance and equitability are given for each of the study years. Mean infraassemblage diversity, sample assemblage diversity, species density, and equitability were all significantly negatively correlated with river streamflow (measured in cubic feet per second) of the year prior to the sample, but were independent of the concurrent year's streamflow. Over the long term, M. funduli and Trichodina sp. were the most, and G. bulbacanthus was the least, abundant. Species pair prevalence and relative density correlations showed few long-term patterns of co-occurrence or microallopatry. The strongest association was between M. funduli and the Neascus sp. and was attributed to similarities in ecological requirements of intermediate hosts.

Ultrastructural evidence for the presence of bacteria, viral-like particles, and mycoplasma-like organisms associated with Giardia spp.

Giardia trophozoites and cysts, isolated from mammalian and avian hosts, were examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and by fluorescent light microscopy for the presence of microbial symbionts. Mycoplasma-like organisms were observed on the surfaces of trophozoites isolated from the prairie vole, laboratory rat, and beaver. Intracellular bacteria were observed by TEM in the trophozoites and cysts of G. microti and by fluorescence microscopy in trophozoites and cysts of Giardia spp. isolated from beaver, muskrat, great-blue heron, and the green heron. Trophozoites of G. muris from rat small intestine contained viral-like particles measuring 60 nm in diameter. These observations suggest that biological associations between Giardia spp. and diverse microbes may be more common than formerly appreciated. It also raises the possibility of transmission of these apparent symbionts, via the Giardia cyst, to other mammalian hosts including man.