Progressive and regressive changes in the nucleus pulposus. Part I. The neonate

Magnetic resonance (MR) imaging, correlated with anatomic sections, was used to characterize the progressive and regressive changes in the nucleus pulposus in neonates. The spines of five fetuses and five full-term infants between 16 and 40 weeks old were studied. In anatomic sections, the nucleus pulposus was sharply demarcated from the anulus fibrosus, Sharpey fibers were conspicuous, and a plate of primitive notochord was evident in the equator of the disk. On long repetition time (TR)/long echo time (TE) or long TR/short TE MR images, Sharpey fibers (low signal intensity) and notochord (low signal intensity) could be differentiated from the high-signal-intensity nucleus pulposus and anulus fibrosus. The major differences between the fetal and infant spines were the amount of notochord in the disk and ossification in the vertebral body.     

Comparative Analysis of Laser Assisted Endoscopie and Conventional Endoscopie Dacryocystorhinostomy

Background

Dacryocystorhinostomy (DCR) is the standard surgical treatment for epiphora caused by obstructions distal to the common canaliculus. Endoscopic DCR (EDCR) and laser assisted DCR (LAEDCR) are becoming increasingly popular alternatives.

Method

69 cases of EDCR were compared with 18 cases of LAEDCR. The success rates were noted at 01 week, 01, 03 and 06 months. The operating time required, incidence of adjuvant procedures, complications and post operative morbidity were recorded.

Results

At the end of 06 months, 100% and 95% success was achieved with LAEDCR and EDCR respectively. Operating time, complication rates and the incidence of adjuvant procedures required were lesser in the LAEDCR group.

Conclusion

In our study both the procedures have comparable success rates, though LAEDCR has an edge over EDCR in terms of decreased duration of surgery, decreased post operative morbidity and lesser complications.Key Words: Epiphora, endoscopic dacryocystorhinostomy, laser assisted endoscopic dacryocystorhinostomy     

Prediction of cytochrome P450 isoform responsible for metabolizing a drug molecule

Background

ATP-binding cassette (ABC) transporters protect cells against unrelated (toxic) substances by pumping them across cell membranes. Earlier we showed that many ABC transporters are highly expressed in hematopoietic stem cells (HSCs) compared to more committed progenitor cells. The ABC transporter expression signature may guarantee lifelong protection of HSCs but may also preserve stem cell integrity by extrusion of agents that trigger their differentiation. Here we have studied whether non-hematopoietic stem cells (non-HSCs) exhibit a similar ABC transporter expression signature as HSCs.

Results

ABC transporter expression profiles were determined in non-hematopoietic stem cells (non-HSCs) from embryonic, neonatal and adult origin as well as in various mature blood cell types. Over 11,000 individual ABC transporter expression values were generated by Taqman Low Density Arrays (TLDA) to obtain a sensitivity comparable with quantitative real-time polymerase chain reactions. We found that the vast majority of transporters are significantly higher expressed in HSCs compared to non-HSCs. Furthermore, regardless their origin, non-HSCs exhibited strikingly similar ABC transporter expression profiles that were distinct from those in HSCs. Yet, sets of transporters characteristic for different stem cell types could be identified, suggesting restricted functions in stem cell physiology. Remarkably, in HSCs we could not pinpoint any single transporter expressed at an evidently elevated level when compared to all the mature blood cell types studied.

Conclusions

These findings challenge the concept that individual ABC transporters are implicated in maintaining stem cell integrity. Instead, a distinct ABC transporter expression signature may be essential for stem cell function. The high expression of specific transporters in non-HSCs and mature blood cells suggests a specialized, cell type dependent function and warrants further functional experiments to determine their exact roles in cellular (patho)physiology.