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Biomedical subjects

Ramin Sam

Publications and source records attributed to Ramin Sam.

6 recordsLinked to original sources
PubMed2006

Glomerular epithelial cells transform to myofibroblasts: early but not late removal of TGF-beta1 reverses transformation.

Studies were carried out to determine whether epithelial-mesenchymal transformation (EMT), well described in renal tubular epithelial cells, also occurs in glomerular epithelial cells and whether it is reversible. To this effect, cultured glomerular epithelial cells were incubated with TGF-beta(1) and their transformation into myofibroblasts was studied. At 4 days, the cells altered their phenotype, as shown by a change in shape, an increase in intracellular staining for alpha-smooth muscle actin (alpha-SMA), a decrease in membrane staining for cytokeratin, and an increase in matrix deposition. Changing the medium after 4 days by excluding TGF-beta(1) and adding fetal bovine serum (FBS) [as a source of epidermal growth factor (EGF) and other growth factors] caused the cells to revert to their original epithelial phenotype. By contrast, when the medium was changed in the same manner after 8 days of exposure to TGF-beta(1), the cells did not revert but remained myofibroblastic. Staining the cells for expression of EGF receptor before and after exposure to TGF-beta(1) caused this receptor, originally present on the plasma membrane, to become partly intracellular after 4 days of TGF-beta(1) exposure and completely intracellular after 8 days of TGF-beta(1) exposure. Kidney sections from 2 models of renal mass reduction were stained. Loss of the epithelial marker (podocalyxin) staining and the acquisition of alpha-SMA staining was observed in the glomeruli. It is concluded that EMT takes place in glomerular epithelial cells in vivo and in vitro. In cultured glomerular epithelial cells, the process can be reversed by early, but not late intervention. It seems that TGF-beta(1) exposure progressively downregulates the EGF receptor on the membrane, rendering the cell refractory to EGF signals critical for maintaining the epithelial phenotype.

Actins↗
PubMed2006

Lipoprotein glomerulopathy: a new apolipoprotein E mutation with enhanced glomerular binding.

We describe a case of lipoprotein glomerulopathy, the second ever reported from the United States, in a Mexican man with a hitherto undescribed mutation in the apolipoprotein E gene (substitution of proline for arginine at position 147 [Arg147Pro]). In this patient, glomerular basement membranes showed double contours and circumferential mesangial extensions, suggesting that deposition of lipids could be injurious to endothelial cells. Immunofluorescence staining of thrombi was positive for apolipoprotein E and B. To study the reason for lipid deposition in glomeruli, we incubated normal human kidney sections with serum from the patient and a healthy control. Apolipoprotein E from the patient's serum showed binding to the glomerular capillary wall, but the control did not, suggesting enhanced binding of the mutated apolipoprotein E to glomerular capillaries. Apolipoprotein E genotyping by means of restriction endonuclease digestion of polymerase chain reaction-amplified genomic DNA showed it to be of the wild-type E3/E3.

Adult↗
PubMed2006

Composition and clinical use of hemodialysates.

A thorough knowledge and understanding of the principles underlying the preparation and the clinical application of hemodialysates can help us provide exemplary patient care to individuals having end-stage renal disease. It is prudent to be conversant with the following: (a) how each ingredient in a dialysate works, (b) the clinical circumstances under which the concentration of an ingredient can be altered, and (c) the special situations in which unconventional ingredients can be introduced into a dialysate. The potential to enrich dialysates with appropriate ingredients (such as iron compounds) is limited only by the boundaries of our imagination.

Acetates↗
PubMed2002

Utility of a peritoneal dialysis leukocyte test strip in the diagnosis of peritonitis.

Expeditious diagnosis of peritonitis remains a significant goal in the management of patients maintained on peritoneal dialysis. Several attempts to use leukocyte esterase reagent strips to diagnose peritonitis have been described. In this study we examined the usefulness of a new reagent strip, the PeriScreen Test Strip, in the diagnosis of peritonitis. A series of 72 peritoneal effluent samples obtained from 22 maintenance peritoneal dialysis patients is reported. In this study, the test strips had a sensitivity of 100% and a specificity of 98.3% as compared to an abnormal leukocyte count. Thus, in the diagnosis of peritonitis we believe that the PeriScreen Test Strip can be used as a simple bedside screening test to exclude peritonitis in peritoneal dialysis patients.

Adult↗
PubMedDate not supplied

Impaired antibody response rates after high dose short interval hepatitis B virus vaccination of immunosuppressed individuals.

BACKGROUND/AIMS: Because a more rapid and high dose vaccination schedule may be advantageous in immunosuppressed individuals to induce an earlier immunization, the aim of the present study was to assess the response to high dose, short interval hepatitis B virus vaccination in various immunosuppressed-patient populations. METHODOLOGY: A total of one hundred and thirty-eight immunosuppressed patients (86 cirrhotics, 42 dialysis patients, 10 allogeneic hematopoietic cell transplants) and 26 healthy subjects as controls were vaccinated utilizing a high dose vaccine (40 mcg) and a shortened immunization schedule. RESULTS: Ninety-two percent of the controls responded to the high dose, short interval hepatitis B virus vaccination schedule. In contrast, only 48% of the immunosuppressed patients seroconverted to anti-HBs positivity (p < 0.001). No difference in the antibody response rate was seen between the various immunosuppressed populations studied. No significant hepatitis B virus vaccination-related adverse effects were seen in any of the groups vaccinated. CONCLUSIONS: Although a high dose, short interval hepatitis B virus vaccination schedule is safe in immunosuppressed patients, the antibody response is still significantly reduced as compared to healthy subjects and only slightly greater than that achieved with standard vaccination schedules, as reported in literature. The possibility of achieving an earlier immunization, however, may be of some advantage to protect acquired viral infection.

Adolescent↗