Characterization of an unusual and complex chromosome 21 rearrangement using somatic cell genetics and cloned DNA probes

In a previous case of a newborn infant with typical Down syndrome, chromosome analysis indicated the presence of an unusual and complex translocation of chromosome 21. The patient's cells contained one normal chromosome 21 and a rearranged, F group-sized submetacentric chromosome. This abnormal chromosome appeared to involve duplication of the distal portion of 21q with translocation to the short arm, and a deletion of C-band-positive centromeric heterochromatin. Using linearly ordered cloned DNA probes, we report the detailed molecular examination of this abnormal chromosome, which has been isolated on a hamster background in a hybrid cell line. Both short arm and pericentromeric sequences are present on this chromosome, as well as distal 21q sequences. However, a substantial portion of proximal 21q is deleted. The distal boundary of this deleted section can be pinpointed within the region between two loci (D21S8 and D21S54), a distance of about 5,000 kb. This study illustrates the power of using precisely mapped, linearly ordered DNA probes to characterize this type of rearrangement. In addition, this hybrid cell line can also be used as a member of a mapping panel to map DNA sequences regionally on chromosome 21.     

Localization of phosphorylated ERK/MAP kinases to mitochondria and autophagosomes in Lewy body diseases

We previously found that sustained ERK activation contributes to toxicity elicited by the parkinsonian neurotoxin 6-hydroxydopamine. In addition, substantia nigra neurons from patients with incidental Lewy body disease, Parkinson disease (PD), and diffuse Lewy body dementia (DLB) display abnormal phospho-ERK accumulations in the form of discrete cytoplasmic granules. In this study, we investigated the subcellular localization of phospho-ERK immunoreactive granules using double label confocal microscopy and immuno-electron microscopy. A small percentage of phospho-ERK granules co-localized with the early endosome marker Rab5, but not with cathepsin D, 20S proteasome beta-subunit, or cytochrome P450 reductase. Phospho-ERK immunoreactivity was often associated with mitochondrial proteins (MnSOD, 60 kDa and 110 kDa mitochondrial antigens), and some vesicular-appearing phospho-ERK granules appeared to envelop enlarged mitochondria by confocal laser scanning microscopy. Ultrastructural immuno-gold studies revealed phospho-ERK labeling in mitochondria and in association with bundles of approximately 10 nm fibrils. Heavily labeled mitochondria were observed within autophagosomes. As mitochondrial pathology may play a pivotal role in Parkinson and other related neurodegenerative diseases, these studies suggest a potential interaction between dysfunctional mitochondria, autophagy, and ERK signaling pathways.     

Identification of a new HLA-B*08 variant, HLA-B*0804

The HLA-B locus is the most polymorphic locus known with currently over 100 different alleles described. Many of these alleles encode variants of the serologically-defined tissue transplantation antigens. This high level of diversity makes accurate tissue typing difficult. Here we present the sequence of a new HLA-B *08 variant, HLA-B *0804. found in Caucasian siblings JH and PF serologically typed as HLA-B51/B59 and HLA-B59/B60, respectively. Additionally, DNA-based typing by the polymerase chain reaction using sequence-specific primers (PCR-SSP) identified HLA-B *51 in JH and HLA-B *4001 in PF. However, PCR-SSP failed to identify a second allele in either of these individuals. The unusual finding of a B59 antigen in a Caucasian and the discrepant molecular typing results suggested that these individuals might express novel HLA molecules. Using denaturing gradient gel electrophoresis (DGGE) followed by direct sequencing, we characterized a novel HLA-B *08 variant, HLA-B *0804. The presence of this allele was confirmed by cloning and sequencing. HLA-B *0804 differed from HLA-B *0801 by only one nucleotide substitution resulting in an amino acid replacement of phenylalanine by serine at position 67. Incidentally, this single nucleotide difference was sufficient to prevent amplification by PCR-SSP. This striking difference between both the serologically typed antigen and the PCR-SSP-identified allele compared to the sequenced allele supports the use of sequence-based typing for the analysis of HLA class I locus alleles.     

Active surveillance is superior to radical nephrectomy and equivalent to partial nephrectomy for preserving renal function in patients with small renal masses: Results from the DISSRM registry

Purpose

We compared renal function outcomes among patients in the surveillance and intervention arms of the DISSRM registry.

Reflections on changes in geriatric dentistry

The development of geriatric dental education programs in the United States and at the University of Iowa over the last twenty years is reviewed. The program at Iowa evolved from a didactic elective program taught by a single faculty person to required didactic and clinical programs that include a special care clinic in the dental school and a mobile unit with portable equipment serving ten area nursing homes with comprehensive care. Factors influencing the curriculum development are identified and discussed, and as no dental schools are the same, some general applications are suggested from the Iowa experience.