Can we use the 6-minute step test instead of the 6-minute walking test? An observational study.

OBJECTIVE: To verify whether or not heart rate is maintained below the calculated submaximal level in healthy, sedentary subjects when they perform the 6-minute step test (6MST) and the 6-minute walking test (6MWT), and to compare the maximal heart rate achieved by the subjects at the end of each test. DESIGN: Observational, cross-sectional study. SETTING: One tertiary centre. PARTICIPANTS: Two hundred and fifty-three participants from a pool of 330 healthy and sedentary subjects between 20 and 80 years of age. INTERVENTIONS: Both the 6MWT and the 6MST were performed in accordance with the American Thoracic Society's statement. Dyspnoea, blood pressure, oxygen saturation and heart rate were measured before and after each test. RESULTS: Mean heart rate immediately after the 6MST was significantly higher than mean heart rate immediately after the 6MWT {125 [standard deviation (SD) 19] vs 111 (SD 17) beats/minute; mean difference 13 (95% confidence interval of the difference 10 to 16); P<0.001}. Moreover, mean heart rate during (3minutes after commencement) the 6MST [118 (SD 18) beats/minute] was statistically higher than mean heart rate at the end of the 6MWT [111 (SD 18) beats/minute; P<0.001]. None of the subjects achieved the calculated submaximal heart rate. CONCLUSIONS: The 6MST and 6MWT are safe and produce submaximal effort in healthy participants. However, they are not interchangeable, and the 6MST requires more energy than the 6MWT.

Detection of bovine papillomavirus type 2 DNA in commercial frozen semen of bulls (Bos taurus).

Papillomaviruses are found in epithelial lesions and are linked to different carcinogenic processes in humans and other animals. Although bovine papillomavirus (BPV) has been characterized as epitheliotropic, the presence of viral DNA has been detected in other sample types, including fresh semen. The aim of this study was to evaluate the presence of BPV DNA in spermatozoa and seminal plasma samples of commercial frozen semen taken from bulls (Bos taurus) and its effects on semen function. PCR assays were conducted with specific primers to detect BPV types 1-6 in 40 semen samples of dairy Gir bulls. The semen quality was assessed by the use of parameters such as motility, vigor, acrosomal integrity and DNA integrity. BPV-2 DNA was detected in all of the sperm cell samples and all the seminal samples; however BPV-1, 3, 4, 5 and 6 could not be detected. The presence of BPV DNA was apparently not a cause of reduced sperm function. This is the first record of BPV-2 DNA the commercial frozen semen taken from dairy Gir cattle by several companies that provide semen. Further studies are needed to assess the viability of the virus and the extent to which it can be spread through semen.

Cholesterol and phospholipids content of yolk from fertilized and unfertilized hen eggs.

Three lipid-containing fractions (granules, low-density lipoproteins (LDL) and infranatant) of fertilized and unfertilized yolks were obtained from hen eggs, either from commercial sources or from Arbor acres hens kept by the Pena Branca Aviário Pernambuco and utilized fresh (laid during the previous 7 days). Total cholesterol (TC) and total phospholipid (TP) levels (mg/g yolk, reported as means +/- SD) were determined. In the yolk granules (insoluble fraction) the levels of TC (2.05 +/- 0.36) and TP (0.90 +/- 0.43) of fertilized egg yolks were similar to the levels of TC (2.20 +/- 0.41) and TP (0.90 +/- 0.14) of unfertilized eggs. The TC levels in the LDL from fertilized egg yolks (8.29 +/- 1.63) were not statistically different from those in unfertilized eggs (7.31 +/- 1.50). In contrast, TC was not detected in the infranatant fraction of unfertilized egg yolks, but was present in the infranatant fraction (1.39 +/- 0.69) of fertilized eggs. The TP levels of LDL (0.73 +/- 0.23) and infranatant (0.32 +/- 0.09) fractions of fertilized egg yolks were significantly lower than the levels of TP in the LDL (1.73 +/- 0.51) and infranatant (0.79 +/- 0.59) fractions of unfertilized eggs. Consequently, the TC/TP ratio (mol/mol) increased in the LDL and infranatant fractions of fertilized egg yolks when compared to unfertilized egg yolks. TC levels were similar in the total yolk of fertilized (10.76 +/- 1.32) and unfertilized (10.33 +/- 1.77) eggs, while the TP levels were significantly lower in the fertilized (1.92 +/- 0.17) than in unfertilized (3.43 +/- 0.97) eggs.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol and phospholipids content of yolk from fertilized and unfertilized hen eggs

Three lipid-containing (granules, low-density lipoproteins (LDL) and infranatant) of fertilized and unfertilized yolks were obtained from hen eggs, either from commercial sources or from Arbor acres henskept by the Pena Branca Aviario Pernambuco and utilized fresh (laid during the previous 7 days). Total cholesterol (TC) and total phospholipid (TP) levels (mg/g yolk, reported as means ñ SD) were determined. In the yolk granules (insoluble fraction) the levels of TC (2.05 ñ 0.36) and TP(0.90 ñ 0.43) of fertilized egg yolks were similar to the levels of TC (2.20 ñ 0.4) and TP (0.90 ñ 0.14) of unfertilized eggs. The levels TC in the LDL from fertilized egg yolks (8.29 ñ 1.63) were not statistically different from those in unfertilized eggs (7.31 ñ 1.50). In contrast, TC was not detected in the infranatant fraction of unfertilized egg yolks, but was present in the infranatant fraction (1.39 ñ 0.69) of fertilized eggs. The TP levels of LDL (0.73 ñ 0.23) and infranatant (0.32 ñ 0.09) fractions of fertilized egg yolks were significantly lower than the levels of TP in the LDL (1.73 ñ 0.51) and infranatant (0.79 ñ 0.59) fractions of unfertilized eggs. Consequently, the TC/TP ratio (mol/mol) increased in the LDL and infranatant fractions of fertilized egg yolks when compared to unfertilized egg yolks. TC levels were similar in the total yolks TC levels were similar in the total yolk of fertilized (10.76 ñ 1.32) and unfertilized (10.33 ñ 1.77) eggs, while the TP levels were significantly lower in the fertilized (1.92 ñ 0.17) than in unfertilized (3.43 ñ 0.97) eggs. These results suggest a transfer of TC from the LDL to the infranatant fraction and a large consumption of TP during the fertilization process

The changes in configuration of the rib cage and abdomen during breathing in the anaesthetized cat.

1. The external surface of the rib cage and abdominal wall in anaesthetized cats was surgically exposed in order to record their movements cinematographically in spontaneous breathing and in paralysed cats, during artificial positive pressure ventilation. 2. Cine-stereophotography was used to allow the recording of the movements of a set of markers placed on the external surface of the trunk wall and the corresponding stereometric data were numerically and graphically processed into three-dimensional drawings. The cine-film frames corresponding to the phases of maximum inflation and deflation of the lungs were analysed to reveal the changes in configuration associated with the respiratory movements of the trunk wall. 3. The changes in shape of the diaphragm and the diaphragm and the displacements of the abdominal viscera between extreme inflation and deflation were recorded by X-ray photography. 4. During spontaneous inspiratory movements, the ribs rotated outwards and rostrally about the costovertebral joints, bringing about an increase in the transverse dimensions of the cage all along its length; these movements were accompanied by a clear-cut caudad displacement of the sternum, caused by the straightening of the costal cartilages and by the widening of the angles defined at sternochondral joints between the sternum and each of the costal cartilages. 5. Neuromuscular blockade abolished muscle tone in the trunk wall, allowing the weight of the viscera markedly to deform its configuration. 6. The inspiratory rib movements of the paralysed animal during artificial inspiration were similar to those during spontaneous breathing but the movements of the sternum were inverted and showed small cranial displacements. 7. The loss of muscular tone under neuromuscular blockade made the abdominal wall more compliant than the rib cage to the positive lung pressure and allowed greater mobility of the viscera with consequent distortion of the shape of the diaphragm. 8. The role of rib cage muscle tone in meeting requirements of purely configurational character in such a shell-like structure is discussed in relation to the optimal mechanical performance of the diaphragm.