Biomedical subjects
G Shuttleworth
Publications and source records attributed to G Shuttleworth.
Oral and intraperitoneal immunization with rotavirus 2/6 virus-like particles stimulates a systemic and mucosal immune response in mice.
We examined the use of a virus-like particle (VLP) as an immunogen by analysing the IgA and IgG response generated in serum, intestinal (fecal), pulmonary and uterine samples. The particle comprised two rotavirus capsid proteins (simian VP2 and murine VP6) generated using recombinant baculovirus expression of the two capsid proteins, which self-assembled into particulate VLP2/6. Mice were immunized orally or intraperitoneally (i.p.) with 0 or 100 microg VLP2/6 with or without 5 microg cholera toxin adjuvant. The results showed a systemic and mucosal immune response to VLP2/6 when administered i.p. and, to a lesser extent, when delivered orally which was not dependent on adjuvant use and further proves the concept of VLP2/6 as an effective immunogen.
Uracil recognition by archaeal family B DNA polymerases.
Archaeal family-B DNA polymerases possess a novel uracil-sensing mechanism. A specialized pocket scans the template, ahead of the replication fork, for the presence of uracil; on encountering this base, DNA synthesis is stalled. The structural basis for uracil recognition by polymerases is described and compared with other uracil-recognizing enzymes (uridine-triphosphate pyrophophatases and uracil-DNA glycosylases). Remarkably, protein-protein interactions between all three archaeal uracil sensors are observed; possibly the enzymes co-operate to efficiently eliminate uracil from archaeal genomes.
In vitro development of pig preantral follicles cultured in a serum-free medium and the effect of angiotensin II.
A novel culture system is reported in which pig preantral follicles (< 300 microm in diameter) with an intact thecal cell layer were isolated and cultured in a serum-free medium for up to 30 days. The medium supported follicle culture after isolation, while maintaining both somatic cell and oocyte viability. Follicles were cultured in groups (n = 3 per group) on collagen-coated wells for 16 days, during which they retained a three-dimensional structure, maintained oocyte viability and increased in diameter and number of somatic cells. Follicle culture for 30 days resulted in a further increase in number of cells, oocyte viability was maintained, and a significant increase in follicle diameter was observed (P < 0.001), with 29% of follicles forming an antrum. Follicles synthesized measurable quantities of progesterone (168 pg per 100 microl per 48 h; no significant increase with time) and increasing quantities of oestradiol (136 pg per 100 microl per 48 h; P < 0.001 with time). Further supplementation of the medium with 100 micromol testosterone l(-1) at day 28 resulted in a significant increase in oestradiol secretion by both antral (P < 0.01) and preantral follicles (P < 0.05). Culture over 30 days in medium with 10(-10) mol angiotensin II l(-1) and further supplementation at day 28 with 100 micromol testosterone l-1 also increased oestradiol synthesis (P < 0.001). These results show that viable preantral follicles may be cultured for extended periods, and indicate that the possible role of angiotensin II in folliculogenesis and steroidogenesis in early development of pig follicles requires further investigation.
A comparison of stereoscopic and monoscopic evaluation of optic disc topography using a digital optic disc stereo camera.
AIMS: To compare stereophotographic and monophotographic optic disc assessments made using a digital optic disc stereo camera. METHODS: Stereo digital optic disc photographs of 150 selected patients who had presented to a glaucoma clinic were assessed by two masked observers on separate occasions using (1) the stereophotographs and a stereoviewer, (2) a single image from the same stereopair. Results were analysed for both right and left eyes separately. 95% tolerance limits for change (TC) and intraclass correlation coefficients (ICC) were calculated and a multivariate analysis using a general linear model for repeated measures was performed. RESULTS: A total of 201 optic disc images of 150 patients (84 females, 108 left eyes) were analysed. Mean age of patients was 64 years. The results for right eyes are as follows (similar results were obtained for left eyes). Intraobserver (stereoscopic compared to monoscopic) measurements of: horizontal cup:disc ratios (CDR), ICC = 0.5995 and 0.7269, TC = 34% and 27%; vertical CDR, ICC = 0.8298 and 0.817, TC = 25% and 27%; area CDR, ICC = 0.7757 and 0.8259, TC = 28% and 25%; circumference CDR, ICC = 0.7618 and 0.8103, TC = 28% and 25%. Interobserver measurements of: horizontal CDR, ICC stereoscopic (SS) = 0.7287; monoscopic (MS) = 0.5030; TC SS = 30%; MS = 32%; vertical CDR, ICC SS = 0.8439; MS = 0.7106; TC SS = 25%; MS = 31%; area CDR, ICC SS = 0.8392; MS = 0.6276; TC SS = 26%; MS = 32%; circumference CDR, ICC SS = 0.8433; MS = 0.6438, TC SS = 26%; MS = 31%. Systematic bias between observers and between methods was within acceptable limits. CONCLUSIONS: This study using a digital stereo camera indicates that there may be little benefit of stereoscopic imaging over monoscopic imaging despite demonstrating small but inconsistent differences between both observers and methods.
Autoradiographic determination of angiotensin II receptors in prepubertal and postpubertal pig ovarian tissue.
The aim of this study was to determine whether specific receptors for angiotensin II are present in prepubertal and postpubertal pig ovaries using an autoradiographic technique and computerized densitometry. Frozen sections were cut from prepared samples, and (125)I-labelled angiotensin II and the angiotensin II receptor subtype-specific nonpeptide antagonists for receptor subtype 1, AT(1) (GR117289) and subtype 2, AT(2) (PD123319) were used. In both pre- and postpubertal pig ovarian tissue, specific receptors for angiotensin II were demonstrated. These receptors had a density of 2487.6 (range: 267.5-5177.6, n = 4) and 3703.8 (range: 1819.9-5207.8, n = 4) fmol per mm(2), respectively, and dissociation constants of 130.0 and 26.3 nmol l(-1), respectively (prepubertal ovarian range: 106.0-165.4 nmol l(-1); postpubertal ovarian range: 26.1-100.3 nmol l(-1); P < 0.05, Mann-Whitney U test). AT(1) receptors with a K(i) for (125)I-labelled angiotensin II of 346.9 nmol l(-1) in the prepubertal and 268.1 nmol l(-1) in the postpubertal ovary were located predominantly in follicle wall tissue. Competitive inhibition studies using both angiotensin II antagonists resulted in a decrease in K(i) with prepubertal tissue (283.7 nmol l(-1)) and an increase in postpubertal tissue (293.9 nmol l(-1)). Immunocytochemistry using sections from paraffin wax-embedded prepubertal (n = 4) and postpubertal (n = 4) pig ovaries confirmed the presence of AT(1) receptors on the granulosa cell layer, but not the thecal cell layer, of antral follicles in both pre- and postpubertal pig ovarian tissue, and AT(2) receptors within the granulosa cell layer of prepubertal pig ovarian antral follicles. In summary, these results indicate that angiotensin II receptors are of higher affinity in postpubertal tissue than they are in prepubertal tissue, and indicate an active renin-angiotensin system within the pig ovary.
Management of acute eyelid conditions.
Explore the source record for details and available documents.
Compartment switching of WNT-2 expression in human breast tumors.
WNT-2 is a secreted polypeptide with mitogenic effects in murine mammary epithelial cells, but its role in human cancer is unknown. Using RNase protection analysis of primary cell preparations and in situ hybridization analysis, we report that WNT-2 is expressed at low levels in normal human breast fibroblasts but not in epithelial cells. WNT-2 was found to be expressed at high levels in both the epithelium and stroma of 5 of 11 infiltrating carcinomas and 2 of 6 fibroadenomas. The high level of WNT-2 expression in tumor epithelium suggests that tumorigenesis may involve the ectopic expression of WNT-2 and the creation of an autocrine Wnt signaling loop.