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Biomedical subjects

A Landsman

Publications and source records attributed to A Landsman.

6 recordsLinked to original sources
PubMed2006

Fibrin microbeads (FMB) as a 3D platform for kidney gene and cell therapy.

Cell and gene therapy may alter the outcome of renal diseases, such as hereditary nephropathies, acute and chronic glomerulonephritis and allograft nephropathy. However, owing to blockade of many viral and cellular vehicles by the complex glomerular architecture, the exact nature of gene and cell delivery into specific renal compartments remains currently unknown. To study the interaction of viral vectors with a variety of renal cells and mesenchymal stem cells (MSCs), we employed a novel biological three-dimensional (3D) matrix comprised of fibrin microbeads (FMB) in comparison to monolayer cell culture. Our studies showed that renal cells of both established and primary lines can grow efficiently on FMB and differentiate into epithelial structures, as shown by electron microscopy. Gene delivery into renal cells in 3D was observed for several viral vectors and growth in 3D on FMB conferred resistance to renal cancer cells in the context of oncolytic adenoviruses. Finally, MSCs from various rodent species attached to FMB, grew robustly, survived for several weeks and could efficiently be transduced on FMB. Thus, on the basis of growth, differentiation and transduction of renal cells in 3D, FMB emerge as a novel 3D cellular microenvironment that differs substantially from monolayer cell cultures.

Cell Differentiation↗
PubMed2001

Dietary phosphate-dependent growth is not mediated by changes in plasma phosphate concentration.

The present study was undertaken in order to assess the role of dietary phosphate in growth. A diet deficient in phosphate led to a suppression of growth in juvenile rats. The phenomenon is similar to that described for diets deficient in other essential single components such as Mg, Zn or K. However, unlike the other constituents, dietary phosphate restriction affected the growth rate much more than it altered the serum phosphate concentration; addition of phosphate to the drinking water of rats fed a low-phosphate diet restored the growth rate without a concomitant change in serum phosphate concentration. The suppression of growth rate by the deletion of phosphate was associated with a delayed decrease in food intake. This finding implies that the variation in appetite was secondary to the change in growth. The increase in body weight following phosphate supplementation was associated with a concomitant increment in food intake. The phosphate-dependent growth was, however, evident also in rats that were pair-fed with those that were not supplied with phosphate. It is concluded that dietary phosphate-dependent growth is not mediated by changes in phosphate concentrations in the extracellular fluid. It is plausible that signals arising from receptors for phosphate in the digestive system constitute part of the growth control apparatus in rats.

Animals↗
PubMed1994

Bovine bladder compliance increases with normal fetal development.

In this study we characterized the elastic properties of the normal bovine bladder throughout fetal life, the newborn period and into adulthood. The elasticity of the bladder was measured with a novel circularly clamped bladder testing system. Pressurization of a circularly clamped bladder tissue sample caused the tissue to deflect upward repetitively in the shape of a spherical cap. If the centerline deflection is much larger than the tissue thickness, the elastic modulus, considered the inverse of compliance, can be determined using linear regression techniques. The results of our analyses showed that the elastic modulus decreases in direct proportion with increasing gestational age. These data suggest that during normal development of the bovine fetal bladder there is a progressive change from a rather stiff noncompliant bladder characterized by a high elastic modulus to a compliant bladder with a lower elastic modulus. Moreover, the increase in compliance appears in the developmental period when urine production first occurs. These observations suggest that volume work may be a significant event in the normal development process of the bovine bladder and results in an increase in bladder compliance. Conversely, the poorly compliant fetal bladder may explain some of the transient dilatations of the upper urinary tract which have been documented in utero. Finally, from the newborn period to the mature adult bovine we documented a relatively modest increase in the elastic modulus or decrease in bladder compliance which may reflect the normal aging process.

Animals↗
PubMedDate not supplied

The role of combined magnetic field bone growth stimulation as an adjunct in the treatment of neuroarthropathy/Charcot joint: an expanded pilot study.

This study was designed to assess the value of combined magnetic field (CMF) bone growth stimulation in the treatment of acute, phase 1, Charcot neuroarthopathy. Thirty-one subjects were studied. Initially 10 controls and 11 study patients were examined. When the initial results were analyzed, 10 additional study patients were added. The result was a statistically significant reduction in time to consolidation, 23.8 weeks for the control versus 11 weeks for the study group. Additionally, less destruction of the bony architecture was noted in the study group as compared to the control. Thus the results of this expanded pilot study demonstrate the efficacy of CMF in accelerating the consolidation process of acute, phase 1, Charcot joint, and decreasing the amount of residual deformity.

Acute Disease↗