Archive for the ‘Cyclic Modulation’ Category


Cyclic Modulation of Epithelial Glycosylation: DISCUSSION(5)

Nov 18, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

Interesting differences are apparent between the luminal and glandular epithelial compartments, most notably in the human. DBA reactivity, which is largely concentrated at the apical cell surface, is only present in luminal epithelial cells from approximately Day 24 of the cycle, which is significantly later than in glandular cells. This timing is significant since it appears to coincide with the end of the receptive phase for embryo implantation. One could speculate that new glycan structures might mask potential attachment sites, but the functional significance of this observation is unclear. However, DBA might be useful as a novel marker of this phase of luminal epithelial differentiation in the human and nonhuman primates, which has not been well characterized to date. buy ampicillin

(more…)

Cyclic Modulation of Epithelial Glycosylation: DISCUSSION(4)

Nov 17, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

The expression of DBA in the human towards the end of the cycle coincides with the end of the receptive phase for implantation in this species, whereas in the baboon the DBA-binding glycans are present at preimplantation phases. Humans and baboons have asynchronous early development of the tro-phoblast, with penetration of maternal vessels occurring two days later in the human than in the baboon. They also exhibit somewhat different modes of implantation, with the trophoblast of the baboon remaining superficial, and the embryonic membranes overlying the inner cell mass remaining smooth and exposed to the uterine luminal milieu. In contrast, the human trophoblast invades more deeply. buy flovent inhaler

(more…)

Cyclic Modulation of Epithelial Glycosylation: DISCUSSION(3)

Nov 16, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

DISCUSSION(3)

Previous reports of DBA binding to human endometrium have been inconsistent. According to Lee and Damjanov , DBA stained both glandular epithelium and stroma in proliferative endometrium, but Soderstrom found no DBA staining in wax-embedded material, although in frozen sections there was slight staining in both proliferative and secretory phases. Some of this variation in the data may be due to the absence of protease pretreatment of the sections, although it has also been reported that this makes no difference to DBA staining. Despite much variation in reports of DBA binding to proliferative endometrium in the human, most workers are unanimous in describing binding to glands in the secretory phase of the cycle. Implantation occurs at 7-8 days after the LH surge (5.5-6.0 days postovulation), when DBA is just starting to show in an irregular fashion. Once pregnancy is established, DBA and VVA are strongly bound by the glands. buy asthma inhalers

(more…)

Cyclic Modulation of Epithelial Glycosylation: DISCUSSION(2)

Nov 15, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

The abundance and distribution of terminal aGalNAc was determined using a panel of other lectins. The data indicate that lectins with binding specificities that include terminal aGalNAc (HPA, WFA, VVA-B4) bind to luminal and glandular epithelial cells in both species throughout the cycle. One of the most significant findings of this study was the demonstration in the human endometrium of cryptic binding sites for VVA over the entire surface of the luminal epithelium, in contrast to the highly restricted distribution of DBA-binding loci. buy asthma inhaler

(more…)

Cyclic Modulation of Epithelial Glycosylation: DISCUSSION(1)

Nov 14, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

This study demonstrates that DBA recognizes cyclically regulated epithelial glycans in both human and baboon endometrium. However, the timing of expression differs fundamentally in the two species, with abundant binding sites in the baboon in proliferative and early secretory phases, but appearance of such sites delayed in the human until the mid- and late secretory phases. In the baboon, the increased abundance of DBA sites in the late proliferative phase suggests regulation by estrogen, although more direct evidence will have to be sought to support this idea. In the human, there is already evidence that progesterone regulates production of DBA-binding glycans . In the baboon, the regulation by progesterone appears to be inhibitory (this study). flovent inhaler

(more…)

Cyclic Modulation of Epithelial Glycosylation: RESULTS(7)

Nov 13, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

RESULTS(7)

Baboon (Fig. 2D). VVA (mixed isomer), SBA, and HPA showed a pattern of staining similar to but weaker than that of DBA (Fig. 2D), with SBA binding only to a subpopulation of granules, thus giving a fine, delicate stain, while HPA stained slightly more cytoplasmic structures. All three lectins showed loss of staining from Day 5 postovulation onwards, similar to that observed with DBA. WFA showed very strong staining, and this persisted throughout the cycle with respect to the microvillous and basal surfaces. Lateral membrane staining was also retained, although to a weaker degree. After neuraminidase pretreatment, staining with VVA, SBA, and HPA was generally increased, and with VVA and SBA there was de novo staining of the basal plasma membrane/basement membrane. buy ortho tri-cyclen online

(more…)

Cyclic Modulation of Epithelial Glycosylation: RESULTS(6)

Nov 12, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

Other Lectins

Human (Fig. 1, G-l). The staining patterns exhibited by the terminal GalNAc-binding lectins (VVA-B4, SBA, HPA, and WFA) all followed a similar trend: at the proliferative and early secretory phases there was delicate staining of the supranuclear and microvillous regions of the glands and luminal epithelium, which was greatly enhanced after neuraminidase pretreatment (Fig. 1, G-I). Staining increased in both epithelial compartments during the second half of the cycle, with heterogeneity in the staining intensity of various gland profiles and some mosaicism of the gland epithelium, which affected the luminal epithelium to only a minor degree. Binding was again increased after removal of sialic acid, although more in the glandular than the luminal epithelium with SBA and HPA. buy ortho tri-cyclen

(more…)

Cyclic Modulation of Epithelial Glycosylation: RESULTS(5)

Nov 11, 2012 Author: Walter Mcneil | Filed under: Cyclic Modulation

RESULTS(5)

Late secretory phase (Days 12-14 postovulation, Fig. 2G). Reduced staining of the glandular epithelium was evident, with residual patchy binding of DBA to the apical surface and sparse, granular staining of the cytoplasm still sometimes apparent. Only very occasional secretions were seen despite the wide lumina of these glands. After neuraminidase pretreatment, lectin staining of microvillous surfaces was slightly enhanced. DBA staining of the luminal epithelium was mainly restricted to the microvillous surface, with only very occasional cells showing some binding to cytoplasmic granules. Neuraminidase pretreatment produced no change.

(more…)

Categories


Advertising


Most Popular

  • None found

Recent Comments

  • None found