Tag Archives: acetylcholine receptor

br Materials and methods br Results The mean pH

Materials and methods

Results
The mean pH values for Control and PMR cows for each measurement in a 24-h acetylcholine receptor over the duration of the 14-day measurement period are shown in Fig. 1. The typical daily pattern involved a drop in ruminal pH following the morning feed, followed by a small increase in pH before the afternoon feed. A second drop after the afternoon feed was followed by a slow return to maximum values overnight. Daily ruminal pH values are summarised in Table 1. There were no significant differences between means for Control and PMR groups, and no effect of feeding rate for any of the outcomes.
The mean (±SD) corrected serum Hp concentration was 0.062 ± 0.27 mg/mL for Control cows (n = 62) and 0.053 ± 0.20 mg/mL for PMR cows (n = 64). There was no effect of feeding method (P = 0.98) or feeding rate (P = 0.74). None of the 15 rumen-fistulated cows had serum concentrations of Hp >0.009 mg/mL (lowest detectable concentration) whereas 17/110 non-fistulated cows did.

Discussion
The percentage of time that the pH is < 6.0 and 5.6 have both been reported to be relevant for determining sub-optimal rumen function and the presence of SARA, respectively (Mould et al., 1983; Nocek, 1997; Olson, 1997). The indwelling pH boluses allowed normal behaviour of the cows and could record many more values of pH than would have been possible using manual sampling so parameters of time below pH 5.6 and 6 could be precisely evaluated as well as the ‘area’ (time × pH) under those values. This gave a measurement of not only how low the pH went, but for how long it was at this low value. Gozho et al. (2005) defined SARA as a ruminal pH < 5.6 for > 3 h/day. This is 12.5% of the day and, by this definition, even though there was no significant difference between PMR and Control cows in the time spent below the defined ruminal pH thresholds, 12/15 rumen-fistulated cows in the study had SARA. However, there were no health problems recorded in these cows.
Working with the same cows, Auldist et al. (2014) also found no difference between PMR and Control cows for milk yield or composition, body condition score, liveweight or ruminal volatile fatty acid and ammonia concentrations. All of these parameters have been well-described as potential indicators of SARA, or at least of sub-optimal rumen function. (Kolver and de Veth, 2002; Kleen et al., 2003; Nordlund et al., 2004). Additionally, Auldist et al. (2014) measured ruminal pH manually at 2-h intervals for a 24-h period during the same experiment and found no difference in ruminal pH parameters between PMR and Control cows, apart from PMR cows recording a higher maximum pH. Those authors did report that with increasing level of supplement, the area under pH 6 increased. This also highlights the problem of having a defined threshold for SARA when the dynamic nature of the rumen and its pH (and also the way the cow is able to adapt to fluctuations in the pH over time) means that an absolute threshold of optimal ruminal pH or a level of pH defining SARA may be less clear than is often assumed.
The results from this experiment indicate that lower ruminal pH values or more time spent below pH 5.6 were not associated with increased concentrations of Hp. In the time period from 8 days before to 7 days after blood collection, 9/126 blood sampled cows were sick (eight with mastitis, one lame). Four of the eight cows with mastitis during that period were found to have Hp concentrations greater than the upper limit of the normal reference range (<0.1 mg/mL; Ceciliani et al., 2012), whereas only seven of the remaining 118 cows with no signs of clinical disease had serum Hp concentrations >0.1 mg/mL. This supports the evidence in the literature that for conditions resulting in high levels of acute inflammation, such as mastitis (Eckersall et al. 2001), serum Hp concentrations may be a useful marker.

br Recently dynamic chest radiography using a flat

Recently, dynamic chest radiography using a flat panel detector (FPD) system with a large field of view was introduced for clinical use. This technique can provide sequential chest radiographs with high temporal resolution during respiration (17), and the acetylcholine receptor dose is much lower than that of CT. Also, whereas CT and MRI are performed in the supine or prone position, dynamic chest radiology can be performed in a standing or sitting position, which is physiologically relevant. To the best of our knowledge, no detailed study has analyzed diaphragmatic motion during tidal breathing by using dynamic chest radiography.

The purpose of this study was to evaluate diaphragmatic motion during tidal breathing in a standing position in a health screening center cohort using dynamic chest radiography in association with participants\’ demographic characteristics.

Materials and Methods

Study Population

This cross-sectional study was approved by the institutional review board, and all the participants provided written informed consent. From May 2013 to February 2014, consecutive 220 individuals who visited the health screening of our hospital and met the following inclusion criteria for the study were recruited: age greater than 20 years, scheduled for conventional chest radiography, and underwent pulmonary function test. Patients with any of the following criteria were excluded: pregnant (n  =  0), potentially pregnant or lactating (n  =  0), refused to provide informed consent (n  =  22), had incomplete datasets of dynamic chest radiography (n  =  3), had incomplete datasets of pulmonary function tests (n  =  1), could not follow tidal breathing instructions (eg, holding breath or taking a deep breath) (n  =  18), or their diaphragmatic motion could not be analyzed by the software described next (n  =  4). Thus, a total of 172 participants (103 men, 69 women; mean age 56.3 ± 9.8 years; age range 36–85 years) were finally included in the analysis ( Fig 1). The data from 47 participants of this study population were analyzed in a different study (under review). The heights and weights of the participants were measured, and the body mass index (BMI, weight in kilograms divided by height squared in meters) was calculated.

Figure 1. Flow diagram of the study population.Figure optionsDownload full-size imageDownload high-quality image (83 K)Download as PowerPoint slide

Imaging Protocol of Dynamic Chest Radiology (“Dynamic X-Ray Phrenicography”)

Posteroanterior dynamic chest radiography (“dynamic X-ray phrenicography”) was performed using a prototype system (Konica Minolta, Inc., Tokyo, Japan) composed of an FPD (PaxScan 4030CB, Varian Medical Systems, Inc., Salt Lake City, UT, USA) and a pulsed X-ray generator (DHF-155HII with Cineradiography option, Hitachi Medical Corporation, Tokyo, Japan). All participants were scanned in the standing position and instructed to breathe normally in a relaxed way without deep inspiration or expiration (tidal breathing). The exposure conditions were as follows: tube voltage, 100 kV; tube current, 50 mA; pulse duration of pulsed X-ray, 1.6 ms; source-to-image distance, 2 m; additional filter, 0.5 mm Al + 0.1 mm Cu. The additional filter was used to filter out soft X-rays. The exposure time was approximately 10–15 seconds. The pixel size was 388 × 388 µm, the matrix size was 1024  × 768, and the overall image area was 40 × 30 cm. The gray-level range of the images was 16,384 (14 bits), and the signal intensity was proportional to the incident exposure of the X-ray detector. The dynamic image data, captured at 15 frames/s, were synchronized with the pulsed X-ray. The pulsed X-ray prevented excessive radiation exposure to the subjects. The entrance surface dose was approximately 0.3–0.5 mGy.