Analysis of multiple indicator dilution curves for estimation of renal tubular transport parameters

A model is developed to estimate the renal tubular secretory parameters by the multiple indicator dilution (MID) technique. The model allows the calculation of influx (from plasma space to tubular cell), efflux (from tubular cell to plasma space) and sequestration (from tubular cell to luminal side) rate constants. A program using the MID-statistical analysis with least squares fitting (SALS) system for the estimation of these parameters is presented. A trapezoid rule and a non-linear least squares regression were used to carry out definite integrals of cubic spline function and least squares fitting, respectively. The system presented seems to be useful for the precise and rapid estimation of the tubular secretory rate constants.     

Experiments of device failures in a spatial power-combining array

The performance of a spatial power-combining array with device failure is investigated. Experimental results show that the array still combines the power in the broadside direction when the DC open-circuit failure occurs. Analysis of measured radiation patterns indicated that the power radiated from the patch antenna attached to the failed device is much smaller than the power radiated from other patch antennas. The effects of the chip resistor and the RF impedance of failed device are discussed     

Trapped image guide leaky-wave antennas for millimeter wave applications

A leaky-wave antenna is developed from a novel dielectric waveguide for millimeter wave applications. Design formulas and data are provided, and measured and computed results are presented for a prototype model.     

A new approach to species determination for yeast strains: DNA microarray-based comparative genomic hybridization using a yeast DNA microarray with 6000 genes

DNA-DNA hybridization is known as the superior method in the elucidation of relationships between closely related taxa, such as species and strain. For species determination we propose a new DNA-DNA hybridization method: the DNA microarray-based comparative genomic hybridization (CGH) method, using a yeast DNA microarray with approximately 6000 genes. The genome from a yeast strain as a sample strain (Sample) was labelled with Cy3-dye and hybridized to a single DNA microarray, together with the Cy5-labelled genome of S. cerevisiae S288C as a reference strain (Reference). The log2 ratio values [log2[Cy3(Sample)/Cy5(Reference)]: Ratio] of signal intensities of all the gene spots were estimated and divided into the following groups: Ratio < or = -1; -1 < Ratio < 1; 1 < or = Ratio. The hybridization profiles of the genomes of type strains belonging to the genus Saccharomyces were significantly different from that of S. cerevisiae S288C. The Ratio-based grouping allowed us to discriminate between some species from S. cerevisiae more clearly. Furthermore, cluster analysis discriminated between closely related species and strains. Using this method, we were able to not only perform species determination but also to obtain information on alternation in gene copy number of such gene amplifications and deletions with single-gene resolution. These observations indicated that DNA microarray-based CGH is a powerful system for species determination and comparative genome analysis.     

Chromosome translocation induced by the insertion of the URA blaster into the major repeat sequence (MRS) in Candida albicans

Electrophoretic karyotype studies have shown that clinical isolates of Candida albicans have extensive chromosome length polymorphisms. Chromosome translocation is one of the causes of karyotypic variation. Chromosome translocation events have been shown to occur very frequently at or near the major repeat sequence (MRS) on chromosomes. The MRS consists of the repeated sequences RB2, RPS and HOK, and the repeated sequences are considered to be the template for recombination. To investigate which element of the MRS is important for chromosome translocation, we constructed three cassettes, each containing a URA blaster and sequences homologous to one of the repeats, for insertion into the MRS region on the chromosomes. The ura3 strain STN22u2, which shows a stable, standard karyotype, was transformed with each construct. Insertion events with each cassette occurred at almost all chromosomes. Insertion into the RB2 repeat, but not into the RPS repeat, was accompanied by chromosome translocation in some transformants: chromosome translocations between chromosomes R and 7 and chromosomes 1 and 7 were found, as well as deletions of 7A and 7C from chromosome 7. We conclude that the insertion at the RB2 region may initiate chromosome translocation in C. albicans.     

The protein encoded by cancer/testis gene D40/AF15q14 is localized in spermatocytes, acrosomes of spermatids and ejaculated spermatozoa

We have previously identified and cloned a human gene, D40, that is preferentially expressed in testis among normal organs, while it is widely expressed in various human tumor cell lines and primary tumors derived from different organs. In this report, we have examined the expression and localization of this protein in human testis with an antibody specific to D40 protein. In Western analyses, the anti-D40 antibody recognized a major band with a molecular mass of 300 kDa and a minor band of 250 kDa. These bands were not observed in the testis lysates from patients with Sertoli-cell-only syndrome and with Kleinfelter syndrome, who lack germ cells of the testis, indicating that D40 protein is expressed in the germ cells of normal testis. Immunohistochemical studies have revealed that D40 protein is highly expressed in spermatocytes and in the pre-acrosome of round spermatids. In the acrosome, D40 protein expression is observed not inside but outside the acrosome membrane. This is consistent with the finding that the amino-acid sequence at the amino terminal of the D40 protein lacks a hydrophobic signal peptide that is required for proteins to translocate to the membrane. Expression of D40 protein is observed in the acrosome of ejaculated spermatozoa as well, although the level is low compared with that in the pre-acrosome of spermatids. These results suggest that D40 protein plays important roles in spermatogenesis, especially in the formation and maintenance of the acrosome.