An Alu element retroposition in two families with Huntington disease defines a new active Alu subfamily

Alu repetitive elements represent the most common short interspersed elements (SINEs) found in primates, with an estimated 500,000 members in the haploid human genome. Considerable evidence has accumulated that these elements have dispersed in the genome by active transcription followed by retroposition, and that this process is ongoing. Sequence variation between the individual elements has lead to the hierarchical classification of Alu repeats into families and subfamilies. Young subfamilies that are still being actively transposed are of considerable interest, and the identification of one such subfamily (designated 'PV') has lead to the hypothesis that the most recent retroposition events are due to a single master Alu source gene. In the course of our search for the gene causing Huntington disease, we have detected an Alu retroposition event in two families. Sequence analysis demonstrates that this Alu element is not a member of the PV subfamily, but is similar to 5 other Alu elements in the GenBank database. Together, these Alu elements, all of which contain a 7 base-pair internal duplication, define a distinct subfamily, designated as the Sb2 subfamily, providing evidence for a second actively retroposing Alu source gene. These data provide support for multiple source genes for Alu retroposition in the human genome.

A transcription map of the region containing the Huntington disease gene

A transcription map of the Huntington disease gene region was generated by a direct cDNA selection strategy using genomic DNA from the 4p16.3 region surrounding the D4S95 and D4S127 loci. A total of 58 cDNA fragments were obtained from cDNAs derived from fetal brain, frontal cortex, liver and bone marrow following hybridization to overlapping YACs from this region. These cDNA clones were aligned into transcription units by hybridization to specific mRNAs, by sequence overlap and by physical mapping onto overlapping YAC clones. Nine separate transcription units spanning approximately one megabase were detected by RNA hybridization. They represent a minimum number of genes in this region and do not include those genes expressed specifically in tissues not used for the hybridization. The transcription map that is provided by the cDNA segments will lead to the generation of a detailed gene map of this region.

Identification of an Alu retrotransposition event in close proximity to a strong candidate gene for Huntington's disease

Huntington's disease (HD) is a late-onset autosomal dominant neuropsychiatric disorder presenting in mid-adult life with personality disturbance and involuntary movements, cognitive and affective disturbance, and inexorable progression to death. The underlying genetic defect has been mapped to chromosomal band 4p16.3 (refs 2, 3). Analysis of specific recombination events in some families with HD has further refined the location of the HD defect to a 2.2 megabase DNA interval. Using a direct complementary DNA selection strategy we have identified at least seven transcriptional units within the minimal region believed to contain the HD gene. Screening with one of the cDNA clones identified an Alu insertion in genomic DNA from two persons with HD which showed complete cosegregation with the disease in these families but was not found in 1,000 control chromosomes. Two genes including the previously identified alpha-adducin gene and another that encodes for a 12-kilobase transcript, map in close proximity to the Alu insertion site. The 12-kilobase transcript should be regarded as a strong candidate for the HD gene.

Regulation of the phosphate (Pi) concentration in UMR 106 osteoblast-like cells: effect of Pi, Na+ and K+

Osteoblast-like cells possess Na-dependent transporters which accumulate orthophosphate (Pi) from the extracellular medium. This may be important in bone formation. Here we describe parallel measurements of Pi uptake and cellular [Pi] in such cells from the rat (UMR 106-01 and UMR 106-06) and human (OB), and in non-osteoblastic human fibroblasts (Detroit 532 (DET)). In UMR 106-01, cellular [Pi] was weakly dependent on extracellular [Pi] and higher than expected from passive transport alone. [32Pi]-uptake was inhibited by Na deprivation, but paradoxically increased on K deprivation. With Na, 87 per cent of cellular 32P was found in organic phosphorus pools after only 5 min. Na deprivation also decreased cellular [Pi], in both UMR 106-01 and DET, but the decrease was smaller than that in [32Pi]-uptake. Ouabain decreased [32Pi]-uptake and cellular [Pi] in DET, but not in UMR 106-01. Regulation of cellular [Pi] is therefore at least partly dependent on Na/Pi co-transport, but this does not seem to be an exclusive property of osteoblasts.

Active specific immunotherapy: PEM as a potential target molecule

An understanding of the mechanisms involved in a biological phenomenon increases its potential for clinical exploitation. Thus, the simultaneous identification of TAA and the molecular mechanisms involved in antigen presentation and recognition by the immune system make the use of ASI a real possibility. The polymorphic epithelial mucin is expressed on most carcinomas and is highly immunogenic. Furthermore, it has many characteristics that make it potentially an ideal target molecule for ASI: (a) not only is it expressed, but it is upregulated by most carcinomas; (b) it is aberrantly glycosylated by carcinomas, resulting in the exposure of cryptic epitopes; (c) its tandem repeat structure results in there being many epitopes per molecule; (d) its extended structure at the surface means it is one of the first molecules the cells of the immune system encounter; and (e) its apparent ability to elicit HLA unrestricted killing already demonstrated in cancer patients makes it applicable to all individuals.

Safety of intracavitary urokinase with percutaneous abscess drainage

OBJECTIVE

Percutaneous drainage of abscesses is an effective treatment, but the success rate is lower for abscesses that have septa and are multilocular. Several clinical and in vitro studies suggest urokinase may be useful in such cases. Our study was designed to determine the safety of urokinase administered into an abscess cavity during the course of percutaneous drainage.

SUBJECTS AND METHODS

Our study included 26 consecutive patients with 31 abscesses treated with percutaneous drainage. Exclusion criteria included age less than 18 or more than 95 years, CNS disorders (e.g., tumor, vascular problems), coagulation impairments, hepatic failure, pregnancy, and abscesses in the spleen, pancreas, or interloop area. Three doses were used: group 1 (nine patients), 1000 IU of urokinase per centimeter of abscess diameter; group 2 (11 patients), 2500 IU of urokinase per centimeter of abscess diameter; and group 3 (nine patients), 5000 IU of urokinase per centimeter of abscess diameter. These doses were administered every 8 hr for 3 days along with percutaneous drainage. Charts were reviewed to determine success and to detect adverse clinical events. Studies included sequential CT scans; serial serum determinations of hematocrit, prothrombin time, partial thromboplastin time, platelet count, fibrinogen levels, and levels of fibrin degradation products; and serial laboratory analysis of purulent material for fibrinogen and fibrin degradation products. Percutaneous drainage was considered successful if no surgical intervention was required.

RESULTS

Our results showed no significant change in hematologic studies and no bleeding complications. Analysis of purulent material indicated that urokinase remained active in the abscess milieu. Drainage was successful in seven of 11 patients in group 1, all nine patients in group 2, and 10 of 11 patients in group 3. All eight abscesses with septa were successfully drained.

CONCLUSION

Intracavitary urokinase can be given safely during percutaneous drainage of an abscess, with no associated bleeding complications or changes in coagulation parameters.

Cloning and mapping of the alpha-adducin gene close to D4S95 and assessment of its relationship to Huntington disease

The genetic defect underlying Huntington's disease (HD) has been mapped to 4p16.3. Refined localization using recombinant HD chromosome analysis and allelic association analyses have identified two distinct candidate regions. Using a cDNA hybrid selection procedure we have cloned the gene for alpha-adducin, a subunit of a cytoskeletal protein crucial for spectrin-actin membrane plasticity. This gene maps to the proximal 2.2 Mb candidate region within 20 kb of D4S95. Alleles of markers at this locus have been shown to exhibit significant linkage disequilibrium with HD. A 4 kb alpha-adducin transcript was identified which is abundantly expressed in the caudate nucleus, the site of major neuronal loss in HD. Sequencing of the brain alpha-adducin cDNA from two HD patients and an age-matched control did not detect any sequence alterations specific to HD. However, we identified in brain cDNA of both patients and control samples, two alternately spliced brain exons, not previously described in the erythrocyte cDNA. A 93 bp exon is inserted in frame between codon 471 and 472 while a 34 bp exon inserted within codon 621 disrupts the frame and introduces a stop codon after 11 novel amino acids. The mapping of the adducin gene adjacent to D4S95 and its pattern of expression, as well as its potential for distinct alternately spliced variants, reinforces the necessity to accurately assess the role of the expression of this gene in the pathogenesis of HD.

Delineation of a 50 kilobase DNA segment containing the recombination site in a sporadic case of Huntington's disease

No detectable rearrangements involving chromosome 4p16.3 have been observed in patients with Huntington's disease (HD). New mutations for HD could involve structural alterations which might aid the localization of the defective gene. We have reinvestigated a well documented sporadic case of HD. DNA haplotyping with markers between D4S10 and the telomeric locus D4S141 reveals a recombination event in one chromosome of the sporadic HD patient. The site of recombination maps within a 50 kilobase (kb) region, about 700 kb from the 4p telomere. Based on the extremely low HD mutation rate and significantly decreased recombination in the distal region of 4p, we hypothesize a direct link between the site of the recombination and HD in this patient.

Entry of US medical school graduates into family practice residencies: 1991-1992 and 11-year summary

This is the 11th report prepared by the American Academy of Family Physicians on the percentage of each medical school's graduates entering family practice residency programs. Approximately 10.3% of the 15,499 graduates of US medical schools between July 1990 and June 1991 were first-year residents in family practice in October 1991. This compares to 10.7% the previous year. The West North Central region reported the highest percentage of medical school graduates who were first-year residents in family practice programs in October 1991 at 15.3%; the Middle Atlantic and New England regions continued with the lowest percentages. Graduates from publicly funded medical schools were more than twice as likely as those from privately funded schools to be first-year residents in family practice in October 1991, 12.9% compared to 6.2%. Approximately half of medical school graduates entering their first year of family practice residency training in October 1991 selected a program in the same state as their medical schools. This report includes the average percentage for each medical school for the last 11 years, as well as the number and percentage of graduates from osteopathic schools who entered ACGME-accredited family practice residency programs.

Results of the 1992 National Resident Matching Program

After 4 years of declining fill rates through the National Resident Matching Program (NRMP), 74 more positions in family practice residencies were filled in 1992 than in 1991, including 24 more filled with US seniors. The March fill rate (67.5%) increased for the first time since 1987, while the July fill rate (90.7%) increased for the first time since 1984. The Mountain and Pacific regions had the highest fill rates (89.1% and 88.5%, respectively) through the NRMP. Community-based, unaffiliated and university-affiliated programs filled 71.0% and 70.3% of positions offered through the NRMP. University-based and community-based, university administered programs filled 63.8% and 61.0% of positions offered through the NRMP. The other commonly defined primary care specialties of internal medicine and pediatrics also filled increased numbers of positions offered through the NRMP. This is the first year since 1984 in which all three primary care specialties matched more positions than in the previous year. The demand for family physicians in the United States is increasing. Evidence presented here suggests that 1992 may mark the beginning of a new trend toward increased interest in careers in family practice.

Management of suppliers

A proper balance of power is essential between purchasers and suppliers of goods and services to the NHS. Rory Graham gives some advice to those taking on responsibilities as buyers.