Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macroencapsulation of human pancreatic islets inside biomembranes is a promising approach to maintain islet allografts in the diabetic recipient without immunosuppression. In order to test this possibility islets isolated from human pancreata were kept in culture before macroencapsulation in a tissue chamber device. The device consisted of two titanium rings, which supported two flat membranes. These membranes have previously been shown to protect pancreatic islets and fetal lung tissue from allograft rejection and also to promote neovascularization at the membrane surface. In a first series of experiments macroencapsulated human islets were implanted into the epididymal fat pad of athymic, nude mice concomitant to an injection from the same batch of islets under the kidney capsule. Light microscopy of encapsulated and subcapsularly grafted human islets showed that the survival inside the membranes was as good as under the kidney capsule. There was an extensive formation of new blood vessels at the membrane outer surface. In a second series of experiments insulin was extracted from encapsulated human islets implanted either into the epididymal fat pad or subcutaneously. The encapsulated human islets contained as much insulin as the non-encapsulated ones. In these experiments mouse and rat islets were also used. Rodent islets, however, survived less well than the human islets as evidenced by the markedly reduced insulin content values. In a third series of experiments human islets were loaded into the chambers and transplanted into nude mice without the concomitant implantation of non-encapsulated islets under the kidney capsule of the recipienets. Measurements of human C-peptide in serum samples obtained 4 to 8 weeks post-implantation showed considerable concentrations (0.70-185 ng/ml) in all animals. We conclude that isolated human islets survive when implanted into nude mice and continue to release insulin for several weeks. There are, however, species differences suggesting that rodent islets are much more susceptible to the environmental stress inside the membranes than human islets.
 ...
PMID:Structure and function of macroencapsulated human and rodent pancreatic islets transplanted into nude mice. 881 36

Immunobarrier devices may prevent immune destruction of transplanted islets, but there are concerns about survival within such devices. Islets were transplanted in diffusion chambers that employed two laminated polytetrafluoroethylene membranes held together with titanium rings. Five hundred syngeneic mouse islets placed in devices were transplanted into the epididymal fat pads of streptozotocin (STZ) diabetic mice (B6AF1). After 2 wk the devices were removed. Sections were made parallel to the membrane surface. Eight to 13 systematically selected sections of each device were analyzed by planimetry to determine the area of the device space and of the islets within that space. From these data we estimated total volume of the device, volume of islets, and number of islets in a device. The data were segregated into two groups: group I (blood glucose less than 100 mg/dL 2 wk after implantation), and group II (over 150 mg/dL). The volume (mean +/- SE) of devices implanted for 2 wk was 2.1 +/- 0.4 microL in group I and 2.2 +/- 0.2 microL in group II. The islet volume and number within devices were 0.30 +/- 0.06 and 0.17 +/- 0.01 microL, or 340 +/- 50 and 230 +/- 20 islets in group I and group II, respectively. The volume of fibrous tissue in devices was about 0.50 microL. About 10% of the islet tissue had central necrosis. The beta cell volume in a membrane device needed for cure is comparable to that required with islets under the kidney capsule (0.25-0.80 microL). The mass of islets contained within membrane devices needed to cure diabetes is equivalent to that of a graft in an optimal transplant site such as under the kidney capsule.
 ...
PMID:Number and volume of islets transplanted in immunobarrier devices. 948 62

Mammalian spermatozoa acquire fertilizing potential as they undergo a series of changes during epididymal transit. One major facet of such is the alterations in the sperm glycome. Modifications of the sialic acid content within glycan moieties are known to regulate epitope presentation and cellular adhesion and signaling, all of which may be critical for sperm to successfully reach and fertilize the egg. To date, there is paucity of information regarding the sialic acid changes that occur on spermatozoa during epididymal transit. Therefore, the aim of this study was to identify N-linked sialylated glycoproteins in rat epididymal sperm and investigate whether they are regulated during epididymal transit. Sialylated glycopeptides from caput, corpus, and cauda spermatozoa were enriched using titanium dioxide beads. Bound N-linked glycopeptides were released by enzymatic deglycosylation using PNGase F and then analyzed by liquid chromatography tandem-mass spectrometry. A total of 92 unique N-linked sialylated glycopeptides were identified from 65 different proteins. These included members of the disintegrin and metalloproteinase domain-containing protein family (ADAM), Basigin, and Testis-expressed protein 101 (TEX101). Remarkably, label-free quantification showed that more than half of these peptides (48/92) were regulated during epididymal transit. Of interest, the protein TEX101 exhibited PNGase F-resistant deglycosylation under the conditions used in this study. The results from this study showed that changes in the N-linked sialoglycoprotein profile is a major hallmark of sperm maturation in rats.
...
PMID:Quantitative Glycopeptide Changes in Rat Sperm During Epididymal Transit. 2696 20