Localised mitogenic activity in horses following infection with Streptococcus equi

Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, a highly contagious upper respiratory disease of equids. Streptococcus equi produces superantigens (sAgs), which are thought to contribute to strangles pathogenicity through non-specific T-cell activation and pro-inflammatory response. Streptococcus equi infection induces abscesses in the lymph nodes of the head and neck. In some individuals, some abscess material remains into the guttural pouch and inspissates over time to form chondroids which can harbour live S. equi. The aim of this study was to determine the sites of sAg production during infection and therefore improve our understanding of their role. Abscess material, chondroids and serum collected from Equidae with signs of strangles were tested in mitogenic assays. Mitogenic sAg activity was only detected in abscess material and chondroids. Our data support the localised in vivo activity of sAg during both acute and carrier phases of S. equi infection.

172 RELATIONSHIPS AMONG GRANULOSA CELL FGF9 mRNA, FOLLICLE SIZE, AND APOPTOSIS IN CATTLE

Fibroblast growth factor 9 (FGF9) has been suggested to act as a dedifferentiation factor during bovine folliculogenesis, reducing steroidogenesis and increasing cell proliferation in granulosa (GC) and theca (TC) cells, but whether endogenous GC production of FGF9 change during bovine folliculogenesis and atresia/apoptosis is unknown. The objective of these studies was to investigate the relationship between FGF9 mRNA, follicle size, and health status of follicles. Ovaries (n = 10 cows) from a local abattoir classified visually as in midcycle phase (i.e. presence of corpus luteum and large follicles) were collected and categorized as small (1–5 mm), medium (5.1–8 mm) or large (8.1–22 mm) in size (Experiment 1). Follicular fluid (FFL) was aspirated for measurement of oestradiol (E2) and progesterone (P4) via radioimmunoassay and GC collected for RNA extraction. Abundance of mRNA for FGF9 and Caspase-3 (CASP3), an effector of apoptosis, were measured by real-time PCR (qPCR). Data were analysed via factorial ANOVA with main factors: follicle size, follicle estrogenic status, and their interaction. The abundance of GC FGF9 mRNA was greater (P < 0.05) in large E2-inactive (E2P4 concentrations) follicles (10.5 ± 22). The abundance of GC CASP3 mRNA was greater (P < 0.01) in small E2-inactive follicles than in large and medium E2-active and E2-inactive follicles. FGF9 mRNA abundance was not correlated with E2/P4 ratio in FFL, but it was positively correlated with CASP3 mRNA abundance (r = 0.35; P < 0.05). GC CASP3 mRNA abundance was negatively correlated with E2/P4 ratio (r = –0.48; P < 0.01). To investigate the relationship between FGF9 and CASP3 mRNA abundance during experimentally-induced apoptosis, GC from large and small follicles were collected (Experiment 2) and GC were plated in medium containing 10% FCS. GC (n = 3 independent pools for small and large follicles) were then treated with or without 10% FCS for an additional 24 h or 48 h followed by RNA extraction and qPCR for measurement of abundance of FGF9 and CASP-3 mRNA. Statistical analyses with ANOVA included main factors: treatment, duration of treatment, and their interaction. In small-follicle GC, FGF9 and CASP3 mRNA abundance were not correlated and were not affected by treatments. In large follicles, FGF9 mRNA abundance was greater in GC treated without FCS (27.5 ± 2.7) than in GC treated with 10% FCS (6.6 ± 2.7) and tended to differ (P < 0.08) between 24 h (22.5 ± 2.7) and 48 h (11.6 ± 2.7). CASP3 mRNA abundance was greater in GC treated without FCS (310 ± 36) than in GC treated with 10% FCS (140 ± 36) but did not differ (P > 0.10) between 24 h and 48 h. In Experiment 2, there was no significant correlation between FGF9 and CASP3 mRNA (r = 0.28; P = 0.2). These results indicate that FGF9 mRNA abundance is greater in GC from large E2-inactive than from E2-active follicles and its production may be increased in large follicles undergoing apoptosis.

Adult post-mortem imaging in traumatic and cardiorespiratory death and its relation to clinical radiological imaging

The use of post-mortem imaging is expanding throughout the world with increasing use of advanced imaging techniques, such as contrast-enhanced CT and MRI. The questions asked of post-mortem imaging are complex and can be very different, for example for natural sudden death investigation will focus on the cause, whereas for trauma the cause of death is often clear, but injury patterns may be very revealing in investigating the background to the incident. Post-mortem imaging is different to clinical imaging regarding both the appearance of pathology and the information required, but there is much to learn from many years of clinical research in the use of these techniques. Furthermore, it is possible that post-mortem imaging research could be used not only for investigating the cause of death but also as a model to conduct clinically relevant research. This article reviews challenges to the development of post-mortem imaging for trauma, identification and cardiorespiratory death, and how they may be influenced by current clinical thinking and practice.

Prevalence and disease associations of superantigens szeF, szeN and szeP in the S. zooepidemicus population and possible functional redundancy of szeF

Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) causes a variety of infections in a broad range of species. This study broadens prevalence data for three recently identified novel superantigens (szeF, szeN, and szeP) to define links between their presence and disease type. Screening of 437 strains across 190 sequence types (STs) revealed that 50% of strains contained superantigen genes. Results confirmed that the presence of S. zooepidemicus superantigen genes is significantly associated with non-Strangles lymph node abscessation in the horse (p-value = 0.003) and their absence is associated with uterine infection/abortion (p-value = 0.006). This study also investigated the lack of mitogenicity observed in szeF only. Results show that szeF is polymorphic, with 23 different alleles, and mutations altering the protein sequence. Gene expression differences are not responsible for lack of mitogenic activity in these strains. Taken together, these findings suggest that superantigens are important for S. zooepidemicus pathogenesis but SzeF probably has little involvement.

Does the location of the arterial input function affect quantitative CTP in patients with vasospasm?

BACKGROUND AND PURPOSE

In recent years, there has been increasing use of CTP imaging in patients with aneurysmal SAH to evaluate for vasospasm. Given the critical role of the arterial input function for generation of accurate CTP data, several studies have evaluated the effect of varying the arterial input function location in patients with acute stroke. Our aim was to determine the effect on quantitative CTP data when the arterial input function location is distal to significant vasospasm in patients with aneurysmal SAH.

MATERIALS AND METHODS

A retrospective study was conducted of patients with aneurysmal SAH admitted from 2005 to 2011. Inclusion criteria were the presence of at least 1 anterior cerebral artery or MCA vessel with a radiologically significant vasospasm and at least 1 of these vessels without vasospasm. We postprocessed each CTP dataset 4 separate times by using standardized methods, only varying the selection of the arterial input function location in the anterior cerebral artery and MCA vessels. For each of the 4 separately processed examinations for each patient, quantitative data for CBF, CBV, and MTT were calculated by region-of-interest sampling of the vascular territories. Statistical analysis was performed by using a linear mixed-effects model.

RESULTS

One hundred twelve uniquely processed CTP levels were analyzed in 28 patients (mean age, 52 years; 24 women and 4 men) recruited from January 2005 to December 2011. The average Hunt and Hess scale score was 2.89 ± 0.79. The average time to CTP from initial presentation was 8.2 ± 5.1 days. For each vascular territory (right and left anterior cerebral artery, MCA, posterior cerebral artery), there were no significant differences in the quantitative CBF, CBV, and MTT generated by arterial input function locations distal to significant vasospasm compared with nonvasospasm vessels (P > .05).

CONCLUSIONS

Arterial input function placement distal to significant vasospasm does not affect the quantitative CTP data in the corresponding vascular territory or any other vascular territory in aneurysmal SAH.