Epidemiology of giardiasis and cryptosporidiosis in Jamaica

We report the findings of a cross-sectional epidemiologic study of Giardia lamblia and Cryptosporidum infections in Jamaica. Three hundred twenty eight stool samples from patients less than one to 81 years of age were examined using formalin-ether concentration for G. lamblia, Zeihl-Neelsen staining for Cryptosporidium, and the Prospect rapid enzyme immunoassay (EIA; Alexon, Sunnyvale, CA) for parasite diagnosis. The Prospect Giardia rapid assay detected 17 cases of G. lamblia infection compared with six by formalin-ether concentration. However, the Prospect Cryptosporidum EIA did not increase the rate of detection of Cryptosporidum when compared with Zeihl-Neelsen staining. Cryptosporidum infections were most frequently diagnosed in children less than five years old and prevalence decreased with age. In contrast, the prevalence of giardiasis increased as children became older. There were no associations between the infections and stool consistency, clinical manifestations, or sex of the individuals. The contribution of the parasites to childhood morbidity will depend on accurate laboratory diagnosis.     

LEC18, a dominant Chinese hamster ovary glycosylation mutant synthesizes N-linked carbohydrates with a novel core structure

The dominant Chinese hamster ovary cell glycosylation mutant, LEC18, was selected for resistance to pea lectin (Pisum sativum agglutinin (PSA)). Lectin binding studies show that LEC18 cells express altered cell surface carbohydrates with markedly reduced binding to 125I-PSA and increased binding to 125I-labeled Datura stramonium agglutinin (DSA) compared with parental cells. Desialylated [3H]Glc-labeled LEC18 cellular glycopeptides that did not bind to concanavalin A-Sepharose exhibited an increased proportion of species that were bound to DSA-agarose. Most of these glycopeptides bound to ricin-agarose and were unique to LEC18 cells. This fraction was purified from approximately 10(10) cells and shown by 1H NMR spectroscopy and methylation linkage analysis to contain novel N-linked structures. Digestion of these glycopeptides with mixtures of beta-D-galactosidases and N-acetyl-beta-D-glucosaminidases gave core glycopeptides that, in contrast to cores from parental cells, were mainly not bound to concanavalin A-Sepharose or to PSA-agarose. 1H NMR spectroscopy, matrix-assisted laser desorption ionization/time of flight mass spectrometry, electrospray mass spectrometry, and collision-activated dissociation mass spectrometry showed that the LEC18 core glycopeptides contained a new GlcNAc residue that substitutes the core GlcNAc residues. Methylation linkage analysis of the parent compound provided evidence that the GlcNAc is linked at O-6 to give the following novel, N-linked core structure. [formula: see text]     

Transient central hypothyroidism as a cause of failure to thrive in newborns and infants

The course of two neonates and one 4-month-old infant with laboratory and clinical evidence of central hypothyroidism is described. All three presented with failure to thrive and improved after L-T4 therapy. Early recognition and treatment of newborns and infants with central hypothyroidism is important to maximize the potential for growth and development. Two of the three infants have been documented to have transient central hypothyroidism of hypothalamic origin, not previously reported.     

Variation of minority carrier lifetime with level of injection in p-n-junction devices

Minority-carrier lifetime as a function of level of injection has been measured for a number of Si and Ge p-n-junction diodes using reverse recovery and forward current-induced voltage decay methods. It is found that the lifetime always increases with injection level if the effect of the finite thickness of the base of the diode is taken into account while interpreting the experimental results. The decrease in the life-time values reported in the literature appears to be due to erroneous interpretation of the experimental data.     

Preparation and Properties of Tricyclopentadienyl Cerium (IV) Chloride and Bisindenyl Cerium (IV) Dichloride

The reactions of dipyridinium cerium (IV) hexachloride with tetracyclopentadienyl cerium or sodium cyclopentadienide and tetraindenyl cerium or sodium indenide in tetrahydrofuran yield tricyclopentadienyl cerium (IV) chloride and bisindenyl cerium (IV) dichloride. Infrared spectra, thermal stabilities and other characteristics of the compounds have been studied.     

Calculation of the nonstationary interaction of jet flows with a two-dimensional target

A finite-difference scheme is employed to calculate the flow field in the region of interaction of nonuniform jet-type flows with a flat target at normal incidence. Results obtained in the numerical solution are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 22, No. 1, pp. 31–38, January, 1972.