A human protein related to yeast Cdc6p

The unstable proteins Cdc6p and cdc18⁺ are essential and rate limiting for the initiation of DNA replication in Saccharomyces cerevisiae and Schizosaccharomyces pombe, respectively, and also participate in checkpoint controls that ensure DNA replication is completed before mitosis is initiated. We have identified Xenopus and human proteins closely related to Cdc6p/cdc18. The human protein, p62^cdc6, is encoded on chromosome 17q21.3 and includes putative cyclin-dependent kinase phosphorylation sites, destruction boxes, a nucleotide binding/ATPase domain, and a potential leucine zipper. Expression of p62^cdc6 mRNA and protein is suppressed in human diploid fibroblasts made quiescent by serum starvation, and peaks as cells reenter the cell cycle and replicate DNA following serum stimulation. Conservation of structure among proteins involved in initiation suggests that fundamental features of replication complexes are maintained in all eukaryotes.     

Do Segmented Reconstruction Algorithms for Cardiac Multi-Slice Computed Tomography Improve Image Quality?

PURPOSE: To evaluate segmented reconstruction algorithms for spiral multi-slice computed tomography (MSCT) that use data from two cardiac cycles to improve temporal resolution (tau) for imaging of the heart. MATERIALS AND METHODS: An initial group of 78 cardiac patients (heart rates [HR] = 63-167 beats per minute [bpm]) were imaged on a 4-slice, 500 ms gantry rotation time scanner (scanner 1). Images were reconstructed with a single-segment algorithm using data from one cardiac cycle with a reconstruction window of fixed length (tau = 250 ms). Images were also reconstructed with two variants of a multi-segment algorithm using data from two cardiac cycles where only one end of the reconstruction window was fixed and the other end was freely moveable to allow adjustment of tau according to HR: (1) "2-segment fixed start" with fixed start of reconstruction, (2) "2-segment fixed end" with fixed end of reconstruction (for both, tau = 125-250 ms). The resulting image sets were ranked from best to worst (1-3, respectively) in a side-by-side, blinded comparison by two independent readers. A second group of 26 patients (HR = 74-90 bpm) were imaged on a 12-slice, 420 ms gantry rotation time scanner (scanner 2). Data were reconstructed with a single-segment algorithm (tau = 210 ms) and a "2-segment fixed start" algorithm (tau = 105-210 ms) and image sets were ranked from best to worst (1-2, respectively). RESULTS: There was no clear evidence that any one technique is superior for imaging on scanner 1. Reader 1 ranked single-segment images the highest for all HRs, but statistically significant differences among the three algorithms were only found for the lowest HRs (< 80 bpm), where reader 1 preferred single-segment over "2-segment fixed end" techniques (p = 0.048). The highest rankings given by reader 2 varied according to HR: single-segment images were superior for lowest HRs, while "2-segment fixed start" images were superior for HRs > 80 bpm; none of these comparisons reached statistical significance. Improved performance of 2-segment reconstruction was found with scanner 2. Both readers ranked "2-segment fixed start" images the highest (p < 0.01). CONCLUSIONS: The added value of 2-segment cardiac reconstruction algorithms for spiral MSCT was not demonstrated for a 4-slice, 500 ms gantry rotation time scanner but shown to be beneficial for a 12-slice, 420 ms gantry rotation time scanner in the crucial HR range of 74-90 bpm.     

The value of flow cytometric analysis of platelet glycoprotein expression of CD34+ cells measured under conditions that prevent P- selectin-mediated binding of platelets

In the present study, we show by adhesion assays and ultrastructural studies that platelets can bind to CD34+ cells from human blood and bone marrow and that this interaction interferes with the accurate detection of endogenously expressed platelet glycoproteins (GPs). The interaction between these cells was found to be reversible, dependent on divalent cations, and mediated by P-selectin. Enzymatic characterization showed the involvement of sialic acid residues, protein(s). The demonstration of mRNA for the P-selectin glycoprotein ligand 1 (PSGL-1) in the CD34+ cells by polymerase chain reaction (PCR) analysis suggests that this molecule is present in these cells. Under conditions that prevent platelet adhesion, a small but distinct subpopulation of CD34+ cells diffusely expressed the platelet GPIIb/IIIa complex. These cells were visualized by immunochemical studies. Furthermore, synthesis of mRNA for GPIIb and GPIIIa by CD34+ cells was shown using PCR analysis. The semiquantitative PCR results show relatively higher amounts of GPIIb mRNA than of PF4 mRNA in CD34+CD41+ cells in comparison with this ratio in platelets. This finding is a strong indication that the PCR results are not caused by contaminating adhering platelets. MoAbs against GPIa GPIb alpha, GPV, P- selectin, and the alpha-chain of the vitronectin receptor did not react with CD34+ cells. The number of CD34+ cells expressing GPIIb/IIIa present in peripheral blood stem cell (PBSC) transplants was determined and was correlated with platelet recovery after intensive chemotherapy in 27 patients. The number of CD34+CD41+ cells correlated significantly better with the time of platelet recovery after PBSC transplantation (r = .83, P = .04) than did the total number of CD34+ cells (r = .55). Statistical analysis produced a threshold value for rapid platelet recovery of 0.34 x 10(6) CD34+CD41+ cells/kg. This study suggests that if performed in the presence of EDTA the flow cytometric measurement of GPIIb/IIIa on CD34+ cells provides the most accurate indication of the platelet reconstitutive capacity of the PBSC transplant.     

Health Care Utilization and Barriers Experienced by Individuals With Spinal Cord Injury

Objectives

To identify from whom individuals with spinal cord injury (SCI) seek health care, the percentage who receive preventative care screenings, and the frequency and types of barriers they encounter when accessing primary and specialty care services; and to examine how sociodemographic factors affect access to care and receipt of preventative screenings.

Design

Cross-sectional, observational study using an Internet-based survey.

Setting

Internet based.

Participants

Adults (N=108) with SCI who use a wheelchair as their primary means of mobility in the community.

Interventions

Not applicable.

Main Outcome Measures

Health care utilization during the past year, barriers encountered when accessing health care facilities, and receipt of routine care and preventative screenings.

Results

All but 1 participant had visited a primary care provider within the past 12 months, and 85% had had ≥1 visit to specialty care providers. Accessibility barriers were encountered during both primary care (91.1%) and specialty care (80.2%) visits; most barriers were clustered in the examination room. The most prevalent barriers were inaccessible examination tables (primary care=76.9%; specialty care=51.4%) and lack of transfer aids (primary care=69.4%; specialty care=60.8%). Most participants had not been weighed during their visit (89%) and had remained seated in their wheelchair during their examinations (85.2%). Over one third of individuals aged ≥50 years had not received a screening colonoscopy, 60% of women aged ≥50 years had not had a mammogram within the past year, 39.58% of women had not received a Papanicolaou smear within the previous 3 years, and only 45.37% of respondents had ever received bone density testing.

Conclusions

Individuals with SCI face remediable obstacles to care and receive fewer preventative care screenings than their nondisabled counterparts. We recommend that clinics conduct Americans with Disabilities Act self-assessments, ensure that their clinical staff are properly trained in assisting individuals with mobility disabilities, and take a proactive approach in discussing preventative care screenings with their patients who have SCI.     

Immunosuppression following 7,12-dimethylbenz[a]anthracene exposure in B6C3F1 mice--II. Altered cell-mediated immunity and tumor resistance

We have previously demonstrated that the polycyclic aromatic hydrocarbons benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA) produce a marked decrease in spleen weight, spleen and bone marrow cellularity and the number of IgM plaque forming cells generated in response to a T-dependent antigen. Exposure to DMBA, but not B[a]P, increased susceptibility to challenge with PYB6 tumor cells and Listeria monocytogenes suggesting that DMBA produces immune impairment involving cell-mediated immunity (CMI) and tumor resistance mechanisms. In this study, female B6C3F1 mice received total doses of 5, 50 and 100 micrograms DMBA/g of body weight in ten subcutaneous injections of 0.5, 5, or 10 micrograms/g over a 2 week period and CMI and tumoricidal functions were examined 3-5 days following the final injection of DMBA. DMBA exposed mice exhibited suppressed splenic cellularity (decreased 62%) and decreased numbers of resident peritoneal cells (down to 47% of control), although the proportion of T cell and T cell subsets, B cells and macrophages in spleens from exposed mice was not altered. Lymphocyte blastogenesis in response to mitogens was suppressed up to 49% with PHA, 48% with Con A and 76% with LPS. The response to alloantigens in unidirectional mixed lymphocyte culture was depressed as much as 73% following exposure to DMBA. Tumor cytolysis mediated by cytotoxic T cells (CTL) was impaired at doses of 50 and 100 micrograms DMBA/g body weight (88-95% suppressed respectively) as was natural killer cell (NK)-mediated tumor cytolysis (24% and 55% suppressed). Antibody-dependent cytotoxicity was significantly depressed in the highest exposure group. Peritoneal macrophage accumulation was decreased in DMBA-treated mice, but the macrophages present were pushed towards activation. The ability of DMBA-exposed mice to eliminate intravenously injected B16F10 tumor cells from the lungs was not impaired. Since NK- and M phi-mediated tumor cytotoxicity are thought to be primarily responsible for pulmonary elimination of B16F10 melanoma cells, the extent of NK suppression observed following DMBA exposure appeared to be insufficient to alter in vivo B16F10 pulmonary elimination. In contrast, the loss of the CTL tumoricidal response correlated with an increased frequency of tumors following challenge with PYB6 tumor cells.     

Adolescents with type 1 diabetes and risky behaviour

Aim: The aim of the student is to assess whether adolescents with type 1 diabetes mellitus (T1DM) in Italy differ from their healthy peers in regard to risky behaviour. Methods: Data were collected from 215 patients, aged 14 ± 2 years with a mean disease duration of 7 ± 5 years. The control group was comprised of 464 healthy adolescents recruited among high school students. Each patient completed an anonymous confidential questionnaire to determine the prevalence of sexual behaviour, alcohol and tobacco consumption, illicit drug use, and, among patients with diabetes and frequency of mismanagement related to diabetes care. Results: Compared with controls, subjects with diabetes showed a similar rate of sexual intercourse among males and lower rates among females (34.8% vs 35.5%, p NS and 29.4% vs 41.4%, p < 0.05, respectively). Males in the diabetes group reported a higher rate of tobacco use, whereas females showed similar or higher rates of use for every illicit drug studied. Among patients with diabetes, those who are engaged in risky behaviour showed a higher rate of treatment mismanagement (76% vs 34%, p < 0.01). Conclusion: Adolescents with T1DM are as likely as their healthy peers to engage in risky behaviour, indicating the potential benefit of anticipatory guidance concerning glycaemic control and increased risk of acute and chronic complications.     

THE EFFECT OF IRRITATION ON THE PERMEABILITY OF THE MENINGES FOR SALVARSAN

The subdural injection of normal salt solution, normal serum, serum salvarsanized in vivo or weak solutions of cyanide of mercury does not demonstrably increase the permeability of the spinal cord or brain for salvarsan which is circulating in the blood at the time of the subdural injection.