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Adnan Z Rizvi

Publications and source records attributed to Adnan Z Rizvi.

5 recordsLinked to original sources
PubMed2006

Bone marrow-derived cells fuse with normal and transformed intestinal stem cells.

Transplanted adult bone marrow-derived cells (BMDCs) have been shown to adopt the phenotype and function of several nonhematopoietic cell lineages and promote tumorigenesis. Beyond its cancer enhancing potential, cell fusion has recently emerged as an explanation of how BMDCs regenerate diseased heptocytes, contribute to Purkinje neurons and skeletal and cardiac muscle cells, and participate in skin and heart regeneration. Although bone marrow-derived epithelial cells also have been observed in the intestine, fusion as a mechanism has not been investigated. Here, we show that transplanted BMDCs fuse with both normal and neoplastic intestinal epithelium. Long-term repopulation by donor-derived cells was detected in all principal intestinal epithelial lineages including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells, suggesting that the fusion partners of the BMDCs are long-lived intestinal progenitors or stem cells. Fusion of BMDCs with neoplastic epithelium did not result in tumor initiation. Our findings suggest an unexpected role for BMDCs in both regeneration and tumorigenesis of the intestine.

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PubMed2005

Forty-eight-hour pH monitoring increases sensitivity in detecting abnormal esophageal acid exposure.

Ambulatory 24-hour esophageal pH measurement is the standard for detecting abnormal esophageal acid exposure (AEAE), but it has a false negative rate of 15% to 30%. Wireless 48-hour pH monitoring (Bravo; Medtronic, Shoreview, MN) may allow more accurate detection of AEAE versus 24-hour pH monitoring. Forty-eight-hour wireless data were reviewed from 209 patients at three different tertiary care referral centers between 2003 and 2005. Manometric or endoscopic determination of the lower esophageal sphincter helped place the Bravo probe 5 to 6 cm above the lower esophageal sphincter. A total of 190 studies in 186 patients had sufficiently accurate data. There were 114 women and 72 men with an average age of 51 years. AEAE was defined by a Johnson-DeMeester score greater than 14.7 and was obtained in 115 of 190 studies (61%). Only 64 of 115 patients (56%) demonstrated AEAE for both days of the study, whereas 51 of 115 patients (44%) demonstrated AEAE in a single 24-hour period. There was no difference in the prevalence of AEAE on day 1 versus day 2 only (26% vs. 18%, P = .26). Compared with 24-hour alone data, 48-hour data showed 22% more patients with AEAE. Frequent day-to-day variability in patients with AEAE may be missed by a single 24-hour pH test. Forty-eight-hour pH testing may increase detection accuracy and sensitivity for AEAE by as much as 22%.

Female↗
PubMed2005

Epithelial stem cells and their niche: there's no place like home.

Stem cells hold the promise of novel therapy for treating diseases. Unfortunately, the use and study of embryonic stem cells are currently clouded by ethical controversy. Adult stem cells offer a unique alternative in that they may be isolated, studied, or manipulated without harming the donor. Currently, several obstacles for use of adult stem cells as therapy exist. First, the ability to identify most adult stem cells is impeded by lack of stem cell markers. Second, in vitro systems for manipulating adult stem cell populations are often not well defined. Finally, our understanding of how adult stem cells are regulated within their niche is in its infancy. Next to the hematopoietic stem cell, epithelial stem cells are one of the most widely studied stem cell populations. Even so, the diversity between epithelial functions in different organs makes it difficult to determine whether common themes exist in regulating these related stem cells. Although each epithelial stem cell niche possesses unique features to facilitate its specialized functionality, they likely share many common aspects of regulation. The purpose of this review is to compare how the cell signaling influences the stem cell and its niche in rapidly self-renewing epithelia.

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