Inhibition of adhesion of enterotoxigenic Escherichia coli cells expressing F17 fimbriae to small intestinal mucus and brush-border membranes of young calves

Enterotoxigenic Escherichia coli strains expressing F17 fimbriae bind to the intestinal mucosa of young calves. F17 fimbriae recognize receptors present in the mucus layer and the brush-border membranes from duodenum, jejunum and ileum. The adhesion of E. coli F17 can be inhibited by several glycoproteins. Adhesion is also inhibited by pretreatment of mucus and brush-border membranes with sodium metaperiodate. The use of glycoconjugates as potential adhesion-blockers is further discussed.     

Acute Effects of Dry Needling on Myofascial Trigger Points in the Triceps Surae of Ballet Dancers: A Pilot Randomized Controlled Trial

BackgroundThere is convincing evidence that dancers suffer injuries to the triceps surae musculature. Research on the immediate effects of dry needling (DN) is limited, and it is important to understand the acute effects of this treatment prior to performance.PurposeThe purpose of this pilot study was to assess the immediate effects of DN on myofascial trigger points in terms of skin surface temperature, pain, active and passive range of motion, and torque production in the triceps surae of ballet dancers.Study DesignRandomized, double-blinded pilot studyMethodsProfessional ballet dancers that fit inclusion and exclusion criteria (n=11) were randomly assigned to an experimental or control group. The dancers had three pre-determined standard point (SP) measurement spots that were used as a baseline for surface temperature comparisons. The dancers were also palpated for trigger point (TP) spots. Both SP and TP spots were marked for future measurements. The experimental group received DN, while the control group received sham DN (SHAM) to their bilateral calves at the TP spots. Immediately prior to and following treatment, both DN and SHAM groups were tested for skin surface temperature, pain, range of motion, and plantar flexion torque by blinded assessors. Paired t-tests and independent t-tests were performed to examine for differences between groups.ResultsThe surface temperature for the TP was higher than the SP measurements prior to intervention (Right calf p= .014; Left calf p= .031). There were no significant changes in VAS scale reported pain and ROM. The plantar flexion torque measurements showed an increase in the DN group of the left calf at the angular velocity of 60 degrees/sec.ConclusionThis was a unique pilot study examining the acute effects of DN on professional ballet dancers. The results were limited due to low sample size. However, the methodology for this study and surface temperature results invites future research.Level of evidenceLevel 1b     

Evaluation of immunization with gut membrane glycoproteins of Ostertagia ostertagi against homologous challenge in calves and against Haemonchus contortus in sheep

Peanut and ConA lectins were used as ligands to isolate glycoproteins from detergent extracts of adult Ostertagia ostertagi membranes. As judged by their profiles following SDS-PAGE, these fractions closely resembled the equivalents from Haemonchus contortus which are derived from the nematode intestinal cell microvillar membranes and which are highly protective when used as antigens. Groups of calves were immunized with the peanut and ConA binding fractions of Ostertagia, either as separate or pooled antigens mixed with QuilA as adjuvant. All calves, including controls immunized with adjuvant only, were challenged with a single dose of infective Ostertagia larvae and faecal egg counts were monitored for 5 weeks. In two experiments where the antigen fractions were pooled, moderate (30-50%), but statistically significant reductions in egg output were observed, but the number of worms was not diminished. No significant protection was observed in a third trial where groups of calves were immunized with peanut or ConA binding proteins given separately. Two further trials were conducted in sheep immunized with the same Ostertagia fractions but challenged with Haemonchus. Irrespective of whether they were administered separately or together, the Ostertagia antigens cross protected efficiently against Haemonchus reducing egg counts by between 81% and 97% and worm numbers by between 57% and 84%.     

Comparative disposition of ricobendazole enantiomers after intravenous and subcutaneous administration of a racemic formulation to calves

The enantioselective disposition kinetics of the benzimidazole anthelmintic, ricobendazole (RBZ), have been characterized after its intravenous (iv) and subcutaneous (sc) administration as a racemic formulation to cattle. The (+) and (-) RBZ enantiomeric forms were recovered in plasma after iv and sc administration of the racemic RBZ formulation, using a chiral phase based HPLC method. A biexponential plasma concentration versus time curve was observed for both RBZ enantiomers following the iv treatment. Total body clearance was higher for (-) RBZ (150.4 mL/h. kg) compared with that obtained for the (+) RBZ antipode (78.1 mL/h. kg). The elimination half-life of the (-) RBZ enantiomer was shorter (T1/2beta: 2.67 h) compared with the (+) enantiomer (T1/2beta: 5.41 h). The plasma availability (expressed as AUC) was significantly higher for (+) RBZ compared with that obtained for the (-) antipode following both treatments. The enantiomeric ratio in plasma at T(0) was close to unity (50% of each enantiomer); the analysis of the concentration ratios (+) RBZ/(-) RBZ, demonstrated an increase in the proportion of (+) RBZ during the time course of the kinetics after both iv and sc treatments. The results presented herein show the enantioselective disposition kinetics of RBZ in cattle and are a further contribution to the understanding of the kinetic behaviour of these sulphoxide-containing benzimidazole anthelmintics in ruminants.     

A short protocol for muscle MRI in children with muscular dystrophies

The use of muscle magnetic resonance imaging in patients with muscular dystrophies or congenital myopathies has been limited. We describe the development of a short protocol to be used in young patients with neuromuscular disorders. The protocol includes transverse T1-weighted spin echo sequence images of thighs and calves. The total scanning time is less than 30 minutes, and can be easily applied to patients over the age of 4 years without any need for sedation. Although only the leg muscles are imaged, the images obtained can still help to identify specific patterns of muscle involvement and provide additional help in the differential diagnosis of muscle disorders with overlapping clinical features.     

荷斯坦公犊牛生产小白牛肉的研究

选用11头初生重43.05±4.52kg的荷斯坦公犊牛,群养模式下,全乳饲喂生产小白牛肉,实验期120d。试验研究了犊牛的喂乳量,生长发育规律,乳的转化率、屠宰率、净肉率和经济效益等内容。试验表明,公犊牛日喂乳量、日增重随着日龄的增加而增加,实验日喂乳量9.99±0.21kg,日增重为0.92±0.05kg,全期乳的转化率1.32,末体重153.6±4.38kg,每头牛总喂乳量为1199.0±25.05kg,犊牛的屠宰率和净肉率分别为60.0%和45.68%,每头牛可纯获利2932元,经济效益可观。     

Nitric Oxide Regulation of Gonadotrophin Secretion in Prepubertal Heifers1

Mechanisms responsible for the pulsatile release of gonadotrophin secretion in prepubertal heifers are not fully known. We have shown that an excitatory amino acid agonist, N-Methyl-D,L-aspartic acid (NMA), induces an immediate release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in prepubertal heifers. Nitric oxide (NO) has also emerged as an important regulator of LH release in rats. This study was designed to test the role of NO in the regulation of gonadotrophin release as well as the possible mediation by NO of the effects of NMA and gonadotrophin releasing hormone (GnRH) on gonadotrophin secretion in heifer calves. In experiment 1, four groups of five prepubertal heifers (33 weeks old) received one of the following treatments: (1); N-G-nitro-L-arginine methyl ester (L-NAME, a NO synthase inhibitor, 35 mg/kg, i.v., once); (2) NMA (4.7 mg/kg, i.v., once); (3) L-NAME+NMA (as above); and (4) Vehicle (saline, i.v.). All heifers in all groups were also challenged with a bolus injection of GnRH (10 ng/kg, i.v., once). Blood samples were collected every 15 min for 10 h. L-NAME was injected after the first blood sample, NMA after 2 h and GnRH after 6 h of blood sampling. Administration of L-NAME alone, suppressed the spontaneous pulses of LH (P<0.04). Heifers in the NMA group responded with a significantly greater LH release than did the heifers in the L-NAME+NMA group (P<0.05). Following the GnRH challenge, heifer calves treated with L-NAME or NMA had higher LH pulse responses than the controls (P<0.05). In a second experiment, four groups of five heifer calves (34 weeks old) were given one of the following treatments: (1) L-NAME (as above); (2) L-arginine, a NO precursor (ARG, 100 mg/kg/h, i.v. drip infused for 6 h starting 2 h after first blood sample was taken); (3) L-NAME+ARG (as above); and (4) Vehicle (saline i.v. bolus and drip for 6 h). Blood samples were taken every 10 min for 8 h. Administration of L-NAME suppressed the pulsatile release of LH and FSH (P<0.05). Compared to the control group, infusion of ARG by itself did not change the pattern of LH secretion (P>0.05); however, in heifers given L-NAME, ARG restored a normal pattern of LH pulses, similar to the control values (P>0.05). It was therefore concluded that NO is involved in the regulation of LH, and possibly FSH, secretion and that NO may mediate, at least in part, the stimulatory effects of NMA on LH, and to some extent FSH, release. The responses to GnRH led us to suggest that NO may have inhibitory effects on the pituitary and NMA may have increased pituitary sensitivity to GnRH.     

Relationships of stress responses with plasma oxytocin and prolactin in heifer calves

Oxytocin and prolactin are potential candidates for the regulation of behavioral and physiological stress responses in the brain. To investigate the neurobiological basis of individual differences in stress responses in cattle, we examined the association of behavioral and hypothalamo-pituitary-adrenal axis reactivity to acute stressors and basal and stimulated levels of oxytocin and prolactin. Twenty Holstein heifer calves aged 2 weeks were subjected to a 10 min open-field test (OFT) followed by presentation of a feeding bucket for 15 min in the OF. If the calf contacted the bucket, a blast of air was applied to its muzzle (surprise test). Jugular blood samples collected before and after both tests were analyzed for oxytocin, prolactin, and cortisol. Relationships of basal and percent change in oxytocin or prolactin with behavioral responses in each test and percent change in cortisol were analyzed using principal components analysis and Spearman rank correlations. Plasma cortisol and prolactin concentrations were significantly elevated by the tests (p < 0.005), but plasma oxytocin concentration did not significantly change (p > 0.1). Four principal components explained 56.1% of the total variation: curiosity, general activity, fearfulness, and dependence on humans. Curiosity was inversely correlated with basal oxytocin level (rS = − 0.683, p < 0.05). General activity was positively correlated with prolactin reactivity (rS = 0.448, p < 0.05) and inversely with oxytocin reactivity to the novel environment (rS = − 0.717, p < 0.05). Fearfulness tended to correlate positively with basal oxytocin level (rS = 0.583, p < 0.1). Dependence on humans correlated with none of the hormonal parameters. The relationships of basal oxytocin level with curiosity and fearfulness for novel environments are of particular interest for future study.