Influence of oxytetracycline susceptibility as a first-line antibiotic on the clinical outcome in dairy cattle with acute Escherichia coli mastitis.

The purpose of this study was to clarify the therapeutic effects of oxytetracycline (OTC) as a first-line antibiotic in cattle with acute Escherichia coli mastitis and systemic signs. Drug susceptibility was determined by the minimum inhibitory concentration (MIC) of E. coli isolated from cows with acute E. coli mastitis (n=38). Cattle were divided into OTC-susceptible (S, n=30) and OTC-resistant (R, n=8) groups. They were further subdivided according to susceptibility to the antibiotic used as a second treatment, into susceptible-susceptible (SS, n=30), resistant-susceptible (RS, n=5), and resistant-resistant (RR, n=3) groups. Clinical signs on the day after initial treatment were compared between S and R groups as short-term indicators of treatment effects. The 28-day survival rate of cattle was then compared among SS, RS, and RR groups as a long-term indicator of treatment effects. There were no differences in clinical signs between S and R groups on the day after the first dose, but the 28-day survival rate was significantly greater in the SS group than in the RR group (P=0.04). The results demonstrated that an effective drug is essential for first-line treatment of acute coliform mastitis. However, anticipating the effectiveness of a first-line antibiotic based on clinical symptoms at the second day of treatment is impossible. It is important to build a picture of drug resistance trends in cattle herds for empirical selection of antibiotics to be administered.

Randomized clinical trial to evaluate the effectiveness of enrofloxacin as a second-line antibiotic for treatment of acute Escherichia coli mastitis.

The objective of the present study was to evaluate the effectiveness of enrofloxacin (ERFX) as a second-line antibiotic for treatment of acute Escherichia coli (E. coli) mastitis. Forty-two cows with naturally occurring acute E. coli mastitis were enrolled. On the first day of treatment (day 0), empirically selected antibiotics (oxytetracycline: n = 32, kanamycin: n = 10) were administered. Although systemic signs improved in 10 cows (first-line group), the signs remained unchanged or worsened in 32 cows on day 1, including two cows that were found dead. The 30 surviving cows were randomly assigned to second-line groups constituting an ERFX group (n = 19) or a control group (n = 11) that was treated with other antibiotics. Response to each treatment was evaluated by measuring clinical signs from day 0 to day 3, subsequent quarter milk recovery, and the 60-day survival rate. Appetite on day 3 was significantly better in the ERFX group compared to the control group. No significant differences were observed in the 60-day survival rate or the subsequent milk recovery between the ERFX group and the control group. Thus, the use of ERFX as a second-line antibiotic for the treatment of acute E. coli mastitis could induce a rapid appetite recovery.

Ultrasonic measurement of bone thickness for spinal surgery.

We measured the thickness of the transverse structures associated with the bovine coccygeal transverse processes (bone specimen) by using ultrasonic waves and examined the reliability of this measurement for use in spinal surgery. We first measured the velocity of ultrasonic waves propagating in the spinous process. We then made a hole in the transverse process with an air drill and placed an ultrasonic transducer with a center frequency of 10 MHz in the hole. The time of reflection of the ultrasonic wave from the underside of the transverse process was detected to estimate the remaining bone thickness. The thickness estimated by using ultrasound was compared with the thickness measured by microscopic examination. We could detect reflection waves from the underside of the transverse process in 91.7% of cases (i.e., 22 of 24 measurements using 6 bones from 3 cows). The thickness of the transverse processes in which we detected the waves varied from 0.24 to 6.8 mm. The 95% limit of agreement between ultrasonic and histological measurement was 0.71 mm. Pearson's correlation coefficient showed a strong and positive relationship between the two measurements (r = 0.97, n = 22, P <0.0001).

Effects of mosapride citrate, metoclopramide hydrochloride, lidocaine hydrochloride, and cisapride citrate on equine gastric emptying, small intestinal and caecal motility.

OBJECTIVE: Although extensive work has been done to elucidate the beneficial and unfavorable effects of gastrointestinal prokinetic agents in humans, little is known on the effects of these agents in horses. In this study, we compared the effects of mosapride, metoclopramide, cisapride, and lidocaine on equine gastric emptying, jejunal and caecal motility and evaluated these agents' adverse drug reactions (ADRs). ANIMALS: Seven healthy adult Thoroughbreds. PROCEDURE: Mosapride 1.0mg/kg and 2.0mg/kg, metoclopramide 0.2mg/kg, and cisapride 1.0mg/kg were dissolved in 100mL distilled water for oral administration. Lidocaine 1.3mg/kg was mixed with 500 mL saline for a 30-min intravenous infusion. Oral administration of 100mL distilled water was used as control. Gastric emptying was evaluated using (13)CO(2) breath test, and jejunal and caecal motility was assessed by electrointestinography. RESULTS: The present study demonstrates that mosapride at doses of 1.0mg/kg and 2.0mg/kg facilitates gastric emptying in horses. Improved jejunal motility was observed following administration of mosapride (1.0mg/kg and 2.0mg/kg), metoclopramide (0.2mg/kg), and cisapride (1.0mg/kg). Similarly, improved caecal motility was observed following administration of mosapride (2.0mg/kg). CONCLUSIONS AND CLINICAL RELEVANCE: This study shows that among the prokinetic agents studied here, only mosapride (2.0mg/kg) promotes jejunal and caecal motility in horses. Considering mosapride ADRs profile, it is believed that this compound is useful in the treatment of diseases associated with decreased GI motility, including postoperative ileus.

A preliminary study of (13)c-phenylalanine and (13)c-dipeptide breath tests in horses.

This study aimed to establish a standard dose and sample collection time for (13)C phenylalanine and (13)C-Dipeptide breath test in horses. To evaluate dose-dependent effects, healthy horses received 2.5 mg/kg, 5 mg/kg, and 10 mg/kg (13)C phenylalanine dissolved in 1 ml/kg distilled water and 1.25 mg/kg, 2.5 mg/kg, and 5 mg/kg (13)C dipeptide dissolved in 2 ml/ kg distilled water. Tmax was observed during the sample collection time. For (13)C phenylalanine, the standard deviation of Cmax at 5 mg/kg was lower than that of 10 mg/kg. For (13)C dipeptide, the standard deviation of Tmax was the lowest at 5 mg/kg. This study revealed that an optimal dose for breath tests with (13)C phenylalanine and (13)C dipeptide may be 5 mg/kg in horses.

Effect of osteogenic protein-1 on the matrix metabolism of bovine tendon cells.

Tendon rupture is a common sports injury in adults. However, the mechanical properties of repair tissue are inferior to those of normal tissue. To accelerate tendon healing, an in vivo approach using growth factors has been applied and has shown evidence for the efficacy of biological stimulation of the repair process. Recombinant human osteogenic protein-1 (rhOP-1) has been shown to be effective in stimulating matrix production by various connective tissues. To test the effect of rhOP-1 on the matrix metabolism of tendon cells in vitro, bovine tendon cells were cultured in monolayer with various doses of rhOP-1 for 7 days. The addition of rhOP-1 to cell culture media resulted in significant increases in cell proliferation, DNA content, and the synthesis of proteoglycans (PGs) and collagen, compared to control cultures. The relative percentage of large PGs in the OP-1 culture was higher than that in the control culture. In conclusion, we show for the first time that rhOP-1 stimulates the proliferation of tendon cells and their ability to synthesize and accumulate PGs and collagen in their extracellular matrix. These biological properties may be used in the tissue-engineering of tendon tissues.

Restoration of disc height loss by recombinant human osteogenic protein-1 injection into intervertebral discs undergoing degeneration induced by an intradiscal injection of chondroitinase ABC.

STUDY DESIGN: In vivo study of the effect of an injection of recombinant human osteogenic protein-1 into degenerated discs induced by chondroitinase ABC. OBJECTIVE: To investigate the efficacy of an injection of recombinant human osteogenic protein-1 to induce the recovery of disc height, and biochemical and histologic repair, in discs degenerated through enzymatic digestion by chondroitinase ABC. SUMMARY OF THE BACKGROUND DATA: Chondroitinase ABC is currently proposed as a chemonucleolysis agent; however, postchemonucleolysis degeneration is currently unavoidable. Recombinant human OP-1 has been shown to promote extracellular matrix repair in vitro and in vivo. METHODS: Fifty-four adolescent New Zealand white rabbits were used. Four weeks after an initial injection of chondroitinase ABC (10 mU/disc), 5% lactose (10 microL/disc) or recombinant human osteogenic protein-1 (100 microg in 10 microL lactose/disc) was injected. Disc heights were monitored radiographically at 2-week intervals, and rabbits were killed at 6, 8, 12, and 16 weeks after the initial chondroitinase ABC injections. The intervertebral discs were subjected to histologic and biochemical analyses. RESULTS: Significant disc space narrowing was observed in both groups 2 weeks after the injection of chondroitinase ABC. In the chondroitinase ABC/lactose group, this narrowing progressed after the vehicle injection and was sustained for up to 16 weeks. In the chondroitinase ABC/recombinant human osteogenic protein-1 group, the disc height index showed a significant increase at 6 weeks (lactose vs. recombinant human osteogenic protein-1; P < 0.01); this recovery was sustained for up to 16 weeks. The proteoglycan content was higher in the chondroitinase ABC/recombinant human osteogenic protein-1 group than in the chondroitinase ABC/lactose group. However, histologic changes, after the recombinant human osteogenic protein-1 injection, were not observed. CONCLUSIONS: A single injection of recombinant human osteogenic protein-1 into a rabbit disc dramatically reversed the decrease in disc height induced by chondroitinase ABC chemonucleolysis. The recovery was significant and sustained over the next 12 weeks. The therapeutic effects of both chondroitinase ABC chemonucleolysis and recombinant human osteogenic protein-1 injections should be further explored in higher animals before it is applied to humans.

A case of equine motor neuron disease (EMND).

We report a case of EMND in a heavy horse that was bred and trained in Hokkaido, Japan. Clinical symptoms included severe ataxia of all four limbs, tilted head, lethargy, and flaccid lips. Numerous axonal degenerations and swellings were observed in nuclei, mostly in the cerebellar dentate nucleus and the nucleus of the hypoglossal nerve, and in the ventral horn of the spinal cord. In the ventral horn of the spinal cord, neuronal degeneration, swelling, and/or necrosis were observed sporadically. The case was diagnosed as EMND from the clinical symptoms and pathological findings.