Senescence of immortal human fibroblasts by the introduction of normal human chromosome 6.

In these studies we show that introduction of a normal human chromosome 6 or 6q can suppress the immortal phenotype of simian virus 40-transformed human fibroblasts (SV/HF). Normal human fibroblasts have a limited life span in culture. Immortal clones of SV/HF displayed nonrandom rearrangements in chromosome 6. Single human chromosomes present in mouse/human monochromosomal hybrids were introduced into SV/HF via microcell fusion and maintained by selection for a dominant selectable marker gpt, previously integrated into the human chromosome. Clones of SV/HF cells bearing chromosome 6 displayed limited potential for cell division and morphological characteristics of senescent cells. The loss of chromosome 6 from the suppressed clones correlated with the reappearance of immortal clones. Introduced chromosome 6 in the senescing cells was distinguished from those of parental cells by the analysis for DNA sequences specific for the donor chromosome. Our results further show that suppression of immortal phenotype in SV/HF is specific to chromosome 6. Introduction of individual human chromosomes 2, 8, or 19 did not impart cellular senescence in SV/HF. In addition, introduction of chromosome 6 into human glioblastoma cells did not lead to senescence. Based upon these results we propose that at least one of the genes (SEN6) for cellular senescence in human fibroblasts is present on the long arm of chromosome 6.     

Advanced Neuroimaging to Guide Acute Stroke Therapy

Traditionally non-contrast CT has been considered the first choice imaging modality for acute stroke. Acute ischemic stroke patients presenting to the hospital within 3-hours from symptom onset and without any visible hemorrhages or large lesions on CT images are considered optimum reperfusion therapy candidates. However, non-contrast CT alone has been unable to identify best reperfusion therapy candidates outside this window. New advanced imaging techniques are now being used successfully for this purpose. Non-invasive CT or MR angiography images can be obtained during initial imaging evaluation for identification and characterization of vascular lesions, including occlusions, aneurysms, and malformations. Either CT-based perfusion imaging or MRI-based diffusion and perfusion imaging performed immediately upon arrival of a patient to the hospital helps estimate the extent of fixed core and penumbra in ischemic lesions. Patients having occlusive lesions with small fixed cores and large penumbra are preferred reperfusion therapy candidates.     

Recipient's unemployment restricts access to renal transplantation

Equitable distribution of a scarce resource such as kidneys for transplantation can be a challenging task for transplant centers. In this study, we evaluated the association between recipient's employment status and access to renal transplantation in patients with end‐stage renal disease (ESRD). We used data from the United States Renal Data System (USRDS). The primary variable of interest was employment status at ESRD onset. Two outcomes were analyzed in Cox model: (i) being placed on the waiting list for renal transplantation or being transplanted (whichever occurred first); and (ii) first transplant in patients who were placed on the waiting list. We analyzed 429 409 patients (age of ESRD onset 64.2 ± 15.2 yr, 55.0% males, 65.1% White). Compared with patients who were unemployed, patients working full time were more likely to be placed on the waiting list/transplanted (HR 2.24, p < 0.001) and to receive a transplant once on the waiting list (HR 1.65, p < 0.001). Results indicate that recipient's employment status is strongly associated with access to renal transplantation, with unemployed and partially employed patients at a disadvantage. Adding insurance status to the model reduces the effect size, but the association still remains significant, indicating additional contribution from other factors.     

Comparison of neutral and positive enteral contrast media for MDCT enteroclysis

Objective

To compare neutral and positive enteral contrast media for MDCT enteroclysis (MDCTE) in various small bowel diseases.

Materials and methods

40 patients with suspicion of small bowel diseases were divided randomly into two equal groups. In one group, water was used as neutral enteral contrast and in other group, 2% water soluble iodinated contrast was used as positive enteral contrast. All MDCTE were done on a 16-slice multidetector row CT unit. The findings of MDCTE were compared with the standards of reference.

Results

There were 12 cases of abdominal tuberculosis (30%), 5 cases of bowel masses (12%), 4 cases of Crohn's disease (10%), 3 cases of small bowel adhesions (7%), 2 cases of midgut volvulus (5%), 2 cases of segmental enteritis (5%) and 12 of all cases (30%) were normal. There was no statistically significant difference between neutral and positive enteral contrast with regards to bowel distention, contrast reflux and evaluation of duodenum. Abnormal bowel wall enhancement was appreciated only with use of neutral enteral contrast (n = 12). Evaluation of ileocaecal junction was possible in all 20 patients (100%) with positive enteral contrast but in only 17 patients (85%) with neutral enteral contrast. Overall sensitivity and specificity of MDCTE with use of neutral contrast medium (100 and 88% respectively) was greater for evaluation of small bowel diseases, when compared to MDCTE using positive enteral contrast medium (92.8 and 83.3% respectively).

Conclusions

Water is a good enteral contrast medium for MDCT enteroclysis examination and allows better evaluation of abnormal bowel wall enhancement. Ileocaecal junction evaluation is better with positive enteral contrast medium.