Detection of bovine viral diarrhea virus (BVDV) in seropositive cattle

Detection of bovine virus diarrhoea virus (BVDV) in one vaccinated beef cattle and three non-vaccinated dairy herds was investigated on peripheral blood leukocytes (PBL) with or without previous treatment followed by a capture ELISA (cELISA). Using the combination of PHA and polycation treatment, PBL from 229 seropositive cattle were studied and could be classified in four different states of BVDV infection. Lysed PBL from four animals were directly positive in cELISA (Category I), PBL of 17 animals were positive after PHA stimulation (Category II), 15 animals were positive only after PHA stimulation plus polycation treatment (Category III), while virus could not be detected in 193 seropositive cattle. Wild-type BVDV strains were isolated by co-culture on polycation-treated MDBK cells from 11 of these seropositive animals. BVDV antibodies of these same animals were able to neutralize their own virus, indicating that virus persists in PBL in spite of strain-specific antibodies. No apparent change of leukocyte subpopulations could be detected in any category of virus-positive animals. Thus, BVDV may be present in the PBL of some cattle, even in the presence of a specific active immune response.     

The occurrence of nymphal stage of Linguatula serrata in water buffaloes (Bubalus bubalis): nymphal morphometry and lymph node pathology

The mesenteric lymph nodes (MLN) of buffaloes (n = 100) were examined for the presence of parasitic infection. The nymphal stage of Linguatula serrata was observed in two buffaloes. A single white-coloured nymph with transversely striated spines on a segmented body, two pairs of oral suckers and hooks was observed in the MLN. The morphometrics of the nymphs were studied. The affected lymph nodes were grossly enlarged with cyst and showed pathological lesions of fibroblastic reaction with a mild underlying inflammatory zone.     

Relationships between incidence and severity of fusarium head blight on winter wheat in ohio

ABSTRACT To determine the relationship between incidence (I; proportion of diseased spikes) and severity (S; mean proportion of diseased spikelets per spike) for Fusarium head blight of wheat and to determine if severity could be predicted reliably from incidence data, disease assessments were made visually at multiple sample sites in artificially and naturally inoculated research and production fields between 1999 and 2002. Ten distinct data sets were collected. Mean disease intensity ranged from 0.023 to 0.975 for incidence and from 0.0003 to 0.808 for severity. A model based on complementary log-log transformation of incidence and severity performed well for all data sets, based on calculated coefficients of determination and random residual plots. The I-S relationship was consistent among years and locations, with similar slopes for all data sets. For 7 of the 10 data sets and for the pooled data from all locations and years, the estimated slope from the fit of the model ranged from 1.03 to 1.26. Time of disease assessment affected the relationship between incidence and severity; however, the estimated slopes from each assessment time were also close to 1. Based on the width of the 95% prediction interval, severity was estimated more precisely at lower incidence values than at higher values. The number of sampling units and the index of dispersion of disease incidence had only minor effects on the precision with which S was predicted from I. The estimation of mean S from I would substantially reduce the time required to assess Fusarium head blight in field surveys and treatment comparisons, and the observed relationship between I and S could be used to identify genotypes with some types of disease resistance.     

Evaluation of intra- and interobserver reliability and image reproducibility to assess usefulness of high-resolution ultrasonography for measurement of anterior segment structures of canine eyes

OBJECTIVE: To evaluate the usefulness of high-resolution ultrasonography (HRUS) for measurements of anterior segment structures in canine eyes. ANIMALS: 4 clinically normal Beagles. PROCEDURE: Images were obtained from 8 eyes with a handheld 20-MHz transducer. Eleven anterior segment structures on each image were measured 5 times by 2 independent observers. Coefficients of variation (CVs) for measurements were used to assess intraobserver reliability. Interobserver reliability was assessed by comparing measurements obtained by the 2 observers from the same images. Five images were sequentially obtained from 2 locations (ie, superior and temporal) to evaluate image reproducibility. Anterior segment structures were measured once on each image; image reproducibility was assessed by use of the CV for each parameter measured. Imaging location was assessed by comparison of CV for measurements from each location. RESULTS: CVs were < 10% for observer A for all measurements except the ciliary cleft area (11.63%). The CVs were > 10% for observer B for measurements of the angle recess area (18.51%) and ciliary cleft width (17.44%) and area (16.01%). Significant differences in measurements between observers were found for 5 of 11 anterior segment structures. Imaging the superior aspect of the globe provided the most reproducible images, although image reproducibility was still somewhat variable, with the highest and lowest CVs for measurements of 33.01% and 11.32%, respectively, in the superior position. CONCLUSIONS AND CLINICAL RELEVANCE: High-resolution ultrasound images can be used to reliably measure various anterior segment structures. Clinically relevant findings in the anterior segment of canine eyes may be detectable by use of HRUS.     

Evaluation of a percutaneously controlled hydraulic occluder in a rat model of gradual venous occlusion

OBJECTIVE: To evaluate the efficacy of a percutaneously controlled hydraulic occluder (HO) in a rat model of gradual venous occlusion. STUDY DESIGN: Experimental study. ANIMALS: Ten male Sprague-Dawley rats. METHODS: HOs and perivascular transit time ultrasound flow probes were applied to the caudal vena cava (CVC). Occluders in group I rats (n=6) were gradually attenuated over 8 weeks, whereas occluders in group II rats (n=4) were not attenuated. Vena caval blood flow measurements were performed weekly in all rats for 8 weeks. After euthanasia, the CVC was evaluated grossly and by histopathology. RESULTS: Premature occlusion of the vena cava occurred during the 1st week in 3 rats (1 in group I, 2 in group II) because of kinking of the vena cava between the HO and the flow probe. For the remaining rats, mean blood flow in group I decreased significantly from 40.71 mL/min/kg at baseline to 4.68 mL/min/kg at 8 weeks (P=.0094, power=0.91). Group II rats maintained vena caval blood flow at all times during the study. Complete occlusion of the vena cava was confirmed at necropsy in all group I rats. CONCLUSIONS: Gradual occlusion of the CVC of rats was achieved with HOs over 8 weeks. This model is limited by the size of the experimental animals and comparatively large implants. CLINICAL RELEVANCE: HOs may provide a method for gradual occlusion of congenital portosystemic shunts.     

关于食用菌菌丝体液体深层培养的研究

食用菌深层培养是为了适应工业化生产而设计的一项新型技术,深层液体培养食用菌种取代传统的瓶栽菌种不仅适应了工业化生产的需要,而且流程快、用料省,不失为是一种发展食用菌生产的一条新路子。本文根据国外近年来液体深层培养的研究情况,加以综述,供参考。     

Amino acids in the proteins from aragonite and calcite in the shells of Mytilus californianus

Hydroxylysine and hydroxyproline are absent in the calcified proteins of Mytilus. The organic matrices from the calcite layers have a consistently higher ratio of acidic to basic amino acids than the aragonitic shell units. The uncalcified shell units periostracum and outer ligament, have very few acidic residues, which may in part account for the lack of mineralization.