Parvovirus antibodies in vaccinated gilts in field conditions--results with HI and ELISA tests.

This study was conducted to determine the antibody response for porcine parvovirus (PPV) of 39 gilts in field conditions after vaccination. Gilts from four herds endemically infected with PPV were injected twice with a commercial vaccine of inactivated PPV and Erysipelothrix rhusiopathiae. The PPV antibodies were analysed both with haemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) in order to study the agreement between these methods. The possible association between high-antibody titres and reproductive failure (repeat breeding, culling for infertility, < or = 6 piglets born alive) was also investigated. In these study herds, endemically infected by PPV, most gilts (84.6%) had not seroconverted by the age of 6 months. On-field vaccination resulted in a consistent increase of humoral immunity not exceeding the antibody level of 1 : 512 in the majority of gilts in all herds examined. The agreement between ELISA and HI tests was moderate (Spearman's rho = 0.87, kappa = 0.63). The seroconversion over the level >1:512 by mid-pregnancy was not associated with reproductive failure.

Aspects of the transmission of protection against Mycoplasma hyopneumoniae from sow to offspring.

The aims of this study were to describe the variation in concentration of antibodies to Mycoplasma hyopneumoniae in the serum and colostrum of sows, and to compare the amount of antibodies in colostrum with that obtained in the serum of the smallest piglets in a litter. In addition, the efficacy of the passive immunity in natural conditions was studied. The study was performed in a sow pool herd (600 sows) that was endemically infected with M. hyopneumoniae. Blood samples were collected from sows 19 days (n = 25) before and 3 days (n = 15) after farrowing, and a colostrum sample (n = 25) was collected on the day of farrowing. All samples were analysed for antibodies to M. hyopneumoniae with a monoclonal blocking enzyme-linked immunosorbent assay (ELISA). Twelve sows (48%) were high-responders with respect to antibody concentration in colostrum. The amount of blocking decreased in serum during the last weeks of pregnancy and 3 days post-farrowing it was only 53% of the level found in colostrum. At the age of 14 days, 30 of the smallest piglets were weaned. They were divided into three experimental groups, being the offspring of high-responding sows, low-responding sows, or a mix of high- and low-responding sows. The groups were transported to three separated isolation units and were followed until slaughter. At slaughter, lung lesions were not found. Nor could M. hyopneumoniae be demonstrated either by cultivation or by polymerase chain reaction. However, a significant increase in absorbance values, assessed by an indirect-ELISA, was demonstrated in groups established from low-responding sows. It was concluded that a high antibody level in colostrum appeared to protect piglets from M. hyopneumoniae.

Regional eradication of Mycoplasma hyopneumoniae from pig herds and documentation of freedom of the disease.

The objectives of this study were to 1) screen all sow herds in a region for M. hyopneumoniae, 2) to effectuate an eradication programme in all those herds which were shown to be infected with M. hyopneumoniae, and 3) to follow the success of the screening and the eradication programmes. The ultimate goal was to eradicate M. hyopneumoniae from all member herds of a cooperative slaughterhouse (153 farrowing herds + 85 farrowing-to-finishing herds + 150 specialised finishing herds) before year 2000. During 1998 and 1999, a total of 5067 colostral whey and 755 serum samples (mean, 25 samples/herd) were collected from sow herds and analysed for antibodies to M. hyopneumoniae by ELISA. Antibodies were detected in 208 (3.6%) samples. Two farrowing herds (1.3%) and 20 farrowing-to-finishing herds (23.5%) were shown to be infected with M. hyopneumoniae. A programme to eradicate the infection from these herds was undertaken. During March 2000, a survey was made to prove the success of the screening and the eradication programmes. In total, 509 serum samples were collected randomly from slaughtered finishing pigs. Antibodies to M. hyopneumoniae were not detected in 506 of the samples, whereas 3 samples were considered suspicious or positive. Accordingly, 3 herds were shown to be infected. One of the herds was previously falsely classified as non-infected. Two of the herds were finishing herds practising continuous flow system (CF). Unlike finishing herds which practice all-in/all-out management routines on herd level, CF herds do not get rid of transmissible diseases spontaneously between batches, for which reason a screening was made in the rest of the CF herds (total n = 7). Consequently, 2 more infected herds were detected. In addition to the results of the survey, a decreasing prevalence of lung lesions at slaughter (from 5.2% to 0.1%) and lack of clinical breakdowns indicated that all member herds were finally free from M. hyopneumoniae in the end of year 2000.

Varying effects of infections with Mycoplasma hyopneumoniae on the weight gain recorded in three different multisource fattening pig herds.

Pigs in three specialized fattening herds were studied with respect to the effect of infection with Mycoplasma hyopneumoniae on weight gain. Individual pigs were weighed four times at 4-week intervals during the fattening period and their daily weight gain over the rearing period was calculated. A blood sample was collected on each weighing occasion and analysed for the presence of antibodies to M. hyopneumoniae. The lungs of the principals were inspected at slaughter and the extent of pneumonic lesions was registered by a specially developed technique that has been proven to warrant a high degree of repeatability. No serum antibodies to M. hyopneumoniae were detected in one of the herds, and no pneumonic lesions were recorded at slaughter in that herd. In the other two herds, the prevalence of pigs with serum antibodies to M. hyopneumoniae increased from 6 to 54% and from 31 to 81%, respectively, during the fattening period. The prevalence of pneumonic lesions at slaughter in these herds was higher the later the pigs seroconverted. On the other hand, the extension of the lung lesions tended to be higher among pigs that seroconverted early during the rearing period. Infections with M. hyopneumoniae acquired early during the rearing, presumably strengthened by secondary infections and environmental errors, was found to decrease the daily weight gain of the pigs. However, even non-complicated M. hyopneumoniae infections acquired late in the fattening period were associated with reduced daily weight gain. That growth reduction was estimated to be at least 60 g (about 6%) after adjusting for herd, pen, initial weight and sex.

Grading of diffusely infiltrating astrocytomas by quantitative histopathology, cell proliferation and image cytometric DNA analysis. Comparison of 133 tumours in the context of the WHO 1979 and WHO 1993 grading schemes.

The aim of the study was to evaluate the applicability of quantitative histopathology as an aid for grading diffusely infiltrating astrocytomas. Primary astrocytomas were analysed for parameters (mean nuclear size, mitosis count, area fraction of endothelial cells and tumour necrosis, area fraction of nuclei, and Ki-67 (MIB-1) labelling index), which are closely related to the World Health Organization (WHO) 1979 and WHO 1993 grading criteria. All estimates correlated with the WHO histopathological grade and patient outcome. According to the receiver-operating characteristics curve, the presence of tumour necrosis and mitosis count (cut-off at 3 mitoses/mm2 of neoplastic tissue) showed the best sensitivity and specificity in separating patients with different survival. The multivariate survival analyses confirmed this result. A decision-tree model was constructed based on these two variables: twig I with less than 3 mitoses/mm2, twig II with equal or more than 3 mitoses/mm2 but no necrosis, and twig III with tumour necrosis. This model was found to be more strongly associated with survival than the WHO 1979 or WHO 1993 grading schemes. Low-malignancy astrocytomas (WHO grade II or twig I tumours) could be further divided into two prognostic categories by the image cytometric DNA analysis. The results put an emphasis on astrocytoma grading on mitosis counts (grade II vs. III) and tumour necrosis (grade III vs. IV). To standardize the sampling for mitosis counting, it is suggested that a parallel Ki-67 immunostaining be used for the identification of the most proliferative areas.

Monitoring antibodies to Mycoplasma hyopneumoniae in sow colostrum--a tool to document freedom of infection.

In a survey in Finland in 1995, 14,919 colostral whey samples from 530 farrowing herds were analysed by a monoclonal blocking-ELISA to detect antibodies to Mycoplasma hyopneumoniae (M. hyopneumoniae). Antibodies were detected in 274 (1.8%) samples and in 42 herds (7.9%). The median prevalence of sows with antibodies in seropositive herds was 28.2% (range, 2.7-100%). According to clinical and pathological follow-up in finishing herds in 1996, all of the farrowing herds which were seronegative in 1995, were truly non-infected with M. hyopneumoniae. In acutely infected herds, samples collected earlier than 2 h after farrowing were 3 times more likely to contain antibodies than samples collected 2-12 h after farrowing (odds ratio, 3.0; 95% CI, 1.4-6.6). Repeated freezing or spoilage of the colostrum samples did not cause biologically relevant problems for the ELISA. Antibodies to M. hyopneumoniae were shown to persist up to 3 years in some sows. As a conclusion, colostrum samples were very sensitive samples for the screening of herds for M. hyopneumoniae infection and possibly also for a regular surveillance.

The prevalence of Mycoplasma hyopneumoniae in pig herds in western Finland based on the demonstration of antibodies in colostrum by ELISA.

Swine enzootic pneumonia causes heavy economical losses in fattening herds. The aim of this study was to get an estimate of the prevalence of Mycoplasma hyopneumoniae in the province of Vaasa in Western Finland. There were 112 farrowing herds randomly chosen for a survey. Farmers were asked to milk colostrum samples from every sow. Owners of 22 herds did not send enough samples for a herd diagnosis. Altogether 1773 samples (mean 18.1 samples/herd) were analysed in an indirect ELISA for antibodies to Mycoplasma hyopneumoniae. Thirty-five herds were concluded to be infected with Mycoplasma hyopneumoniae. In these herds the mean prevalence of samples with antibodies was 16.3% (range 2.3%-70.0%, median 8.6%). The infected herds were significantly larger than the rest of the herds (no. of sows 27.0 vs. 18.4 respectively). The true prevalence of Mycoplasma hyopneumoniae infection in the province of Vaasa was estimated to be somewhat lower than the apparent prevalence of 39%. The application of colostrum serology is discussed.

Histone mRNA in-situ hybridization in astrocytomas: a comparison with PCNA, MIB-1 and mitoses in paraffin-embedded material.

AIMS: Non-isotopic histone mRNA in-situ hybridization (HmRNA NISH) allows detection of cells in the S phase of the cell cycle in paraffin-embedded tissue. The aim of this study was to evaluate the technique in measuring the proliferative activity of astrocytic neoplasms, and to compare the results with other proliferation estimates and patient survival. METHODS AND RESULTS: The proliferative activity of 71 routinely fixed and paraffin-embedded astrocytomas was studied by light microscopic HmRNA NISH, proliferating cell nuclear antigen (PCNA), Ki67MIB-1 and mitoses. A significant correlation was found between the labelling indices of histone mRNA (the percentage of histone-positive tumour cells: HmRNA-LI), immunohistochemical proliferation marker labelling indices (PCNA-LI: r = 0.64 and Ki67MIB-1-LI: r = 0.44) and mitotic indices (r = 0.45). The results were reproducible as judged by intra- and interobserver agreement (HmRNA/10 HPF (high power fields): r = 0.91 and r = 0.75, respectively, and HmRNA-LI: r = 0.61 and r = 0.62, respectively). The fraction of the cells in the most active cell cycle phases, as suggested by the HmRNA/Ki67 and mitotic index/Ki67 ratios, increased significantly with malignancy grade. In the univariate analysis the association of HmRNA-LI with survival was highly significant (P < 0.0001). Multivariate survival analysis showed that HmRNA-LI was an independent prognostic marker. CONCLUSIONS: Non-isotopic histone mRNA in-situ hybridization assay offers an alternative and reproducible method for measuring proliferative activity (S phase) in tumours under morphological control.

Ophthalmic manifestations of epidemic nephropathy.

An ophthalmic examination was performed on 29 epidemic nephropathy patients consequently treated in the Central Hospital of Central Finland during the acute phase of the disease. Twenty-six of those patients were reexamined after an interval of one month. In the acute phase of the disease pathological ophthalmic changes were found in 15 cases (52%). The symptoms observed were conjunctival injection, oedema, flare and cell reaction in anterior chamber, anisochoria, retinal oedema, acute glaucoma and myopic shift of refraction. The main effect of disease on intraocular pressure was pressure-lowering. The myopic shifts were not dependent on initial refraction. In one case of acute glaucoma this shift could be explained by swelling and forward movement of the lens.