Biomedical subjects

A Whyte

Publications and source records attributed to A Whyte.

At least 109 records · Page 6Linked to original sources

PubMed1975

Amino acids of Diclidophora merlangi (Monogenea).

The level of free amino acids in Diclidophora merlangi is high, comprising over 500 mu moles/g ethanol extracted dry weight. A single amino acid, proline, constitutes some 70% of the total pool. Analysis of parasite protein and host blood and mucus revealed low proline levels, suggesting that the high free pool content was not related to a requirement for protein systhesis or to its abundance in the diet of the worm. Experiments revealed that proline was not involved specifically in osmoregulation, and the reasons for the large amounts present in Diclidophora remain unknown.

Amino Acids↗

PubMedDate not supplied

Localization of antigen defined by a monoclonal antibody to human 32-kDa insulin-like growth factor-binding protein in the sheep uterus at preimplantation stages of pregnancy.

Employing a murine monoclonal antibody to pregnancy-associated endometrial alpha I-globulin, a 32-kDa insulin-like, growth factor-binding protein (IGF-BP) and major product of the decidualized endometrium in the human, reactivity has been detected in the luminal epithelium of the sheep endometrium during the preimplantation period of pregnancy. Staining was associated with supranuclear regions of the cytoplasm. Reactivity was restricted to the pregnant uterus and was distributed throughout the luminal epithelium in both caruncular and intercaruncular regions. The reactivity was absent from endometrial glands in intercaruncular regions. Staining was first detected at day 10, peaked at day 14 of gestation and was absent by day 16. The implications of the induction of the production of this protein by the preimplantation blastocyst in the luminal epithelium is discussed with reference to the potential role of IGF-BP in IGF action in the embryo.

Animals↗

PubMedDate not supplied

Detection of human and murine trophoblast-specific antigens and an assessment of their species specificity.

The distribution and species specificity of human and mouse trophoblast-specific surface antigens detected by heterologous anti-mouse ectoplacental cone (anti-EPC) trophoblast and anti-human first-trimester trophoblast plasma membrane (anti-TrPM) antisera were assessed using several immunochemical and immunolabelling assays. The findings with immunofluorescence assays using anti-EPC antiserum on monolayer cultures indicate that the expression of mouse trophoblast-specific antigens is restricted to the major trophoblast components of the mouse placenta, as well as pre- and early post-implantation trophoblast, and does not occur on fetal, amnion or tumour tissues. The anti-EPC antiserum does not cross-react with human chorionic villous trophoblast. The human trophoblast-specific antigens also displayed species specificity. The anti-TrPM antiserum showed no evidence of cross-reactivity with rhesus monkey, rabbit, guinea pig or mouse trophoblast by immunodiffusion, crossed immunoelectrophoresis, immunofluorescence or immunoperoxidase labelling.

Animals↗

PubMedDate not supplied

Saccharides localized by fluorescent lectins on trophectoderm and endometrium prior to implantation in pigs, sheep and equids.

Pre-implantation blastocysts together with the corresponding maternal endometrium were obtained from pigs, sheep and equids at known stages of pregnancy. Thin sections of fixed tissue were reacted with FITC-labelled conjugates of lectins specific for alpha-L-fucose, N-acetyl-D-glucosamine, D-galactose, N-acetyl-D-galactosamine and alpha-D-manno- and alpha-D-gluco-pyranosyl residues. The pre-implantation blastocysts of both pig and sheep, throughout the period studied, had a continuous reaction for alpha-L-fucose, which has been suggested to be important in compaction and the expression of SSEA-1 antigen in mouse embryos. Reactivity for N-acetylglucosamine appeared in the blastocysts of both pig and sheep prior to implantation. The staining for fucose and acetylglucosamine was restricted to the apical (maternally apposed) aspect of the trophectoderm. No specific reactivity was observed in horse conceptuses; however, discrete regions of endometrial epithelium stained intensely for N-acetylglucosamine, and may represent 'recognition' sites for the implanting embryo.

Animals↗

PubMedDate not supplied

Equine endometrium at pre-implantation stages of pregnancy has specific glycosylated regions.

Pre- and post-implantation endometrial tissue was removed from equids at known stages of pregnancy. Thin sections of this material were reacted with fluorescein conjugates of several lectins. Two lectins in particular, with specificities for L-fucose and N-acetylglucosamine, reacted strongly with the endometrial epithelium. The reaction for N-acetylglucosamine occurred in small patches on the endometrial epithelium and extended to cover the entire epithelial surface and endometrial glands after implantation. L-Fucose was observed in larger surface deposits particularly at the openings of endometrial glands, but did not extend into them either before or after implantation. These observations indicate changes in glycosylated molecules of endometrial epithelium preceding implantation in equids.

Animals↗

PubMedDate not supplied

Ligand modulation of glial activation: cell permeable, small molecule inhibitors of serine-threonine protein kinases can block induction of interleukin 1 beta and nitric oxide synthase II.

Activated glia (astrocytes and microglia) and their associated neuroinflammatory sequelae have been linked to the disease progression of several neurodegenerative disorders, including Alzheimer's disease. We found that the experimental anti-inflammatory drug K252a, an inhibitor of calmodulin regulated protein kinases (CaMKs), can block induction of both the oxidative stress related enzyme iNOS and the proinflammatory cytokine IL-1 beta in primary cortical glial cultures and the microglial BV-2 cell line. We also found that the profile of CaMKIV and CaMKII isoforms in primary cortical glial cultures and BV-2 cells is distinct from that found in neurons. Knowledge of cellular mechanisms and high throughput screens of a pharmacologically focused chemical library allowed the discovery of novel pyridazine-based compounds that are cell permeable ligand modulators of gene regulating protein kinases involved in the induction of iNOS and IL-1 beta in activated glia. Pyridazine-based compounds are attractive for the development of new therapeutics due to the retention of the remarkable pharmacological properties of K252a and related indolocarbazole alkaloids, and presence of enhanced functional selectivity in a comparatively simple structure amenable to diverse synthetic chemistries.

Animals↗

PubMedDate not supplied

Reproductive immunology. Early pregnancy factor.

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Animals↗

PubMedDate not supplied

Leucocyte entry and endothelial E-selectin expression following intradermal Propionibacterium acnes administration.

Immune responses in porcine skin to intradermal inoculation of heat-killed Propionibacterium acnes (HKPA), the major bacterial agent associated with human inflammatory acne, were studied. Pigs were chosen as experimental animals because their skin is similar in structure and composition to that of man and because the use of genetically inbred pigs enables leucocytes to be transferred between animals without eliciting rejection responses. Two pigs were sensitized intradermally with 10 mg of HKPA and were challenged 2 weeks later with doses ranging from 1-100 microg of HKPA in various intradermal sites on the ventral aspect of the abdomen. Four further pigs, previously sensitized with Bacillus Calmette-Guérin (BCG) but not HKPA, were challenged with purified protein derivative (PPD) of bovine tuberculin and HKPA. Entry of(51)Cr-labelled peripheral blood lymphocytes (PBLs) over 48 h was studied in all the challenge sites. Peak PBL entry occurred at 4 h, remaining sustained up to 24 h. There was a dose-dependent effect of HKPA on the level of PBL entry, which was antigen-specific, as few leucocytes were seen in PPD-challenge sites in HKPA-sensitized pigs or in HKPA-challenged sites in BCG-sensitized pigs. There was also a substantial influx of(111)Indium-labelled neutrophils into the lesions. Lymphocytes present were predominantly of the CD3(+)CD2(+)T-cell subset, although gammadelta TCR(+)cells were present also, particularly after 24 h. E-selectin was markedly upregulated on dermal endothelium in the P. acnes sites. The histological infiltration and kinetics were similar to those reported in human inflammatory acne.

Acne Vulgaris↗

PubMedDate not supplied

Mercy mission.

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Attitude of Health Personnel↗

PubMedDate not supplied

The vasectomized testis.

We have performed a qualitative study on effects of vasectomy on the testicular structure. Vasectomy performed with the traditional technique changes testicular structure. At first, the injuries are slight and restricted, but gradually, and in a time-dependent manner, become more severe and extensive. Ultrastructure studies indicate that the spermatogonia and Sertoli's cells are the most resistant to vasectomy, and are even observed in some regenerating testes lacking a complete germinal epithelium. Morphometric studies revealed a decrease in epithelial depth, an increase in the thickness of the basement membrane and in surface of the interstitial space, all significant (P < 0.01) with respect to the control. However, the percentage of the interstitial tissue occupied by cells, did not show any significant difference. We propose that the increase of intraluminal pressure is the essential factor that provokes testicular atrophy.

Animals↗

PubMedDate not supplied

Uncommon women.

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History of Nursing↗

PubMedDate not supplied

Arterial microanastomosis technique by using only one stitch.

The starting point of this work is the description of a microsurgical technique designed to carry out termino-terminal arterial anastomosis in rats. The technique is based on the intussusception of the afferent vessel of the anastomosis in the efferent vessel, both of which are fixed by a horizontal U-shaped stitch. Of the twelve cases which make up this series, haemorrhage appeared in two, and a postanastomotic aneurysm developed in one. The lack of complications both before and after operating, even in the long term, in the balance of the cases (75%), together with the simple and quick procedure of this kind of anastomosis, makes this technique a possible alternative to the classical techniques of vascular microanastomosis in experimental surgery.

Anastomosis, Surgical↗

PubMedDate not supplied

Characteristics of cellular structures derived by tissue culture of pre-implantation blastocysts of the pig.

Tissue mechanically dissociated from blastocysts of the pig around the time of implantation were found to produce, in culture, free-floating multicellular spheroids (trophospheres) and adherent monolayer cells. Ultrastructurally the two cellular layers of the trophospheres were very similar to those of the blastocyst but the trophosphere outer layer characteristically contained very large mitochondria with a vastly expanded matrix and few cristae. Similar mitochondria were also found in the monolayer cells. Using a monoclonal antibody specific for pig trophectoderm, it was found that about 20% of the monolayer cells, and some of the spheroids expressed this trophectodermal antigen. In the latter case the antigen was present only on the surface facing the medium. The spheroids were fluid-filled and occasionally grew inside each other. The monolayer cells were predominantly uninuclear but did form a number of binucleate cells and in older cultures the occasional cell with many nuclei could be seen. The spheroids and the monolayer cells had similar glycoprotein profiles indicating that they were composed of similar cell populations. A glycoprotein of apparent molecular weight 68,000 observed in both spheres and monolayers may represent pig placental alkaline phosphatase. Both trophospheres and monolayer cells were observed to interconvert steroid precursors. It is apparent that the trophospheres share many features of the blastocyst and may thus represent a valuable model system similar to those described in other species for the investigation of their biochemical physiological and immunological properties.

Animals↗

PubMedDate not supplied