Meat tenderness and the calpain proteolytic system in longissimus muscle of young bulls and steers

The objectives of this study were to examine the effects of castration on the calpain proteinase system (mu-calpain, m-calpain, and calpastatin) activities and meat tenderness. Six each, MARC III bulls and steers were slaughtered at approximately 12 mo of age. Longissimus muscle samples were obtained for determining myofibril fragmentation index, Warner-Bratzler shear force, and sensory panel evaluation at 1, 7, and 14 d postmortem, and mu- and m-calpain and calpastatin activities at 24 h postmortem. Bulls produced leaner carcasses with lower (P < .05) quality grades than did steers. Meat from bulls had higher (P < .05) shear force values than meat from steers; however, sensory panelists were unable (P > .05) to detect differences in tenderness or other sensory traits between bulls and steers. Activities of mu- and m-calpain were not affected (P > .05) by castration; however, calpastatin was higher (P < .05) in muscles from the bull carcasses. Lower (P < .05) myofibril fragmentation index values indicate that less proteolysis occurred in muscle from bulls than in muscle from steers during the first 7 d postmortem. Greater calpastatin 24-h activity may be associated with the increased shear force of meat from bulls.     

Computer-aided design and analysis of direct-driven wheel motordrive

This paper presents the computer-aided design (CAD) and performance analysis of a novel direct-driven wheel brushless DC motor drive for electric vehicles (EVs). The proposed motor is a permanent magnet square-wave motor, whose rotor with rare earth magnets forms the exterior of the motor, which can be fitted with a wheel tire to realize the direct drive for each wheel of an EV. The interior stator with its windings is rigidly mounted onto the suspension and frame structure of the vehicle. In order to achieve the direct drive without any mechanical transmission for EVs, the wheel motor has been designed as a low-speed high-torque motor. The design and optimization of the motor geometry was achieved with the aid of finite-element electromagnetic field analysis. Simulation studies on the transient performance of the motor drive were also carried out. This involved the creation of the motor transient model and formulation of a motor control strategy to ensure the wheel motor drive runs efficiently in the entire permitted speed and load range. The application of CAD techniques in the design of this very unconventional drive is described in this paper     

Acid-base and electrolyte effects of shortening steeplechase in a three-day-event

This study was designed to characterise the acid-base and electrolyte effects of shortening the distance required during steeplechase (Phase B) in the face of hot and humid weather conditions during a treadmill-simulated Speed and Endurance test. Eight conditioned Thoroughbred horses underwent 3 randomised permutations of a standardised exercise test on a high speed treadmill. Each test consisted of trotting at 3.7 m/s for 10 min (Phase A); galloping at 11 m/s (Phase B) for 4 (cool laboratory conditions), 3 (hot and humid), or 2 (hot and humid) min; trotting at 3.7 m/s for 30 min (Phase C); and walking at 1.8 m/s for 10 min (Phase X). The treadmill slope was 4% for trotting and galloping and 0% for walking. Cool versus hot and humid conditions were 20 degrees C and 50-60% relative humidity vs. 26-28 degrees C and 80-85% relative humidity, respectively. Pulmonary artery blood samples were obtained at rest prior to exercise (Rest); at the end of Phases A (A10) and B (B2-4); at 10 (C10), 20 (C20) and 30 (C30) min through Phase C; and at 5 min into Phase X (X5). Additional samples for lactate (LA) and glucose (GLC) analysis were obtained 5 min into Phase C (C5) and at the end of Phase X (X10). Samples were analysed for packed cell volume (PCV), haemoglobin (HB), total plasma protein (TP), sodium (Na), potassium (K), chloride (Cl), anion gap (AG), plasma glucose (GLC) and lactate (LA), pH, PCO2, bicarbonate (HCO3) and base excess (BE). Shortening steeplechase distance by 50% under hot and humid conditions (2 min B) resulted in a consistent return to control measurements (4 min B) only for plasma LA. Changes in PCV, HB, TP, K and Cl were related more to the longer galloping distance in the 4 min B trials than to hot vs. cold laboratory conditions. Alternatively, changes in LA, GLC, pH, PCO2 and AG were more related to hot and humid laboratory conditions than they were to galloping distance. These latter variables, when combined with physical measures such as core temperature, bodyweight loss, point of fatigue on Phase C and recovery heart rates may serve as the best monitors of positive responses in future studies of proposed modifications to Phase C, rather than those variables which were more distance than weather-related.     

Distribution of alpha 1A, alpha 1B and alpha 1E voltage-dependent calcium channel subunits in the human hippocampus and parahippocampal gyrus

The distribution of voltage-dependent calcium channel subunits in the central nervous system may provide information about the function of these channels. The present study examined the distribution of three alpha-1 subunits, alpha 1A, alpha 1B and alpha 1E, in the normal human hippocampal formation and parahippocampal gyrus using the techniques of in situ hybridization and immunocytochemistry. All three subunit mRNAs appeared to be similarly localized, with high levels of expression in the dentate granule and CA pyramidal layer. At the protein level, alpha 1A, alpha 1B and alpha 1E subunits were differentially localized. In general, alpha 1A-immunoreactivity was most intense in cell bodies and dendritic processes, including dentate granule cells, CA3 pyramidal cells and entorhinal cortex pre-alpha and pri-alpha cells. The alpha 1B antibody exhibited relatively weak staining of cell bodies but stronger staining of neuropil, especially in certain regions of high synaptic density such as the polymorphic layer of the dentate gyrus and the stratum lucidum and radiatum of the CA regions. The alpha 1E staining pattern shared features in common with both alpha 1A and alpha 1B, with strong immunoreactivity in dentate granule, CA3 pyramidal and entorhinal cortex pri-alpha cells, as well as staining of the CA3 stratum lucidum. These findings suggest regions in which particular subunits may be involved in synaptic communication. For example, comparison of alpha 1B and alpha 1E staining in the CA3 stratum lucidum with calbindin-immuno-reactivity suggested that these two calcium channels subunits may be localized presynaptically in mossy fibre terminals and therefore may be involved in neurotransmitter release from these terminals.     

Increased analytical precision in the hollow cathode discharge emission source by improved discharge current control.

A significant improvement in the precision of the hollow cathode as an emission source is reported. Precision of 1% or less has been observed several times over periods of several hours. An average long-term stability of 4.3% for Ll and 6.0% for Na in the emission signal from microsamples (less than 50 nL) deposited in the hollow cathode discharge source is reported. The improved precision is attributed primarily to the introduction of electronics that hold the discharge current more nearly constant and to the shielding of all wiring to the source from the power supply. A current-controlled switch that is capable of driving a hollow cathode discharge in either dc or pulsed mode is described. This switch is capable of generating current pulses as short as 2 microseconds through a resistive load and greatly improves the discharge stability and repeatability at turn-on in both the dc and pulsed modes. The characteristics of pulses produced by this switch are presented; however, analytical performance is reported only for the dc mode. Temporal current plots are presented for the new instrumentation and compared to plots taken with commonly used current-controlled power supplies. Instrumentation, operation, and sample preparation procedures are described. Typical temporal profiles of the emission signal from microsamples deposited in AI and stainless steel hollow cathodes are given.     

Carpal fractures in children

This study addresses the likelihood of false negative urine pregnancy test results, due to physiological urine dilution as described in some anecdotal reports. In this prospective study 320 pregnancy tests were performed on urine samples of varying concentrations obtained from 40 women, with suspected complications of early pregnancy, who had presented for ultrasound scans. Four different pregnancy tests were used and serum betahCG levels were measured quantitatively. Despite a mean fivefold increase in urine dilution, the pregnancy tests with low betahCG detection limits maintained maximal sensitivity. The detection of betahCG in dilute urine was adversely affected by using pregnancy tests with higher betahCG detection limits and these tests should be used with caution when assessing gynaecological emergencies.     

An extended HLA-DQ-DR haplotype rather than DRB1 alone contributes to RA predisposition

A family with 1 case of retinitis pigmentosa (III-1) and 2 cases of Oguchi's disease (III-2, 3) was examined in terms of electrophysiology as well as molecular biology. The proband (III-3), a 42-year-old female, and 2 older brothers (III-1, 2, aged 52 and 45 years) and 2 unaffected members in the same family participated in this study. Corrected visual acuities of the individuals with Oguchi's disease (III-2, 3) were 1.2. On funduscopy, blood vessels stood out in relief against a metallic-appearing background and a Mizuo-Nakamura phenomenon was evident. Full-field electroretinograms (ERGs) recorded from the proband were indicative of rod dystrophy, but results of other electrophysiological examinations (multifocal ERG, pattern ERG and visual-evoked cortical potential recordings) were within normal limits. Patient III-1 had corrected visual acuities of RE 20 cm/m.m. and LE 30 cm/n.d., severe chorioretinal atrophy in both fundi, and full-field ERG revealed rod-cone dystrophy. Mutation of the arrestin gene (1147de1A) was detected in all 3 patients. Visual function in each patient coincides with that of retinitis pigmentosa or Oguchi's disease, respectively.     

Molecular forces between membranes displaying neutral glycosphingolipids: evidence for carbohydrate attraction

The surface force apparatus was used to determine the fundamental forces governing the adhesion between mixed bilayer membranes comprising lactosyl ceramide (LacCer) and di-tridecanoyl-phosphatidyl choline. Forces between membranes were quantified as a function of the glycolipid surface densities, which ranged from 0 to 30 mol %. Control measurements of the forces between pure phosphatidylcholine membranes and mixed bilayers of lactosyl ceramide with phosphocholine showed that the steric thickness of the carbohydrate headgroups increased from 19 to 25 A when the glycolipid density increased from 10 to 20 mol %. The layer compressibility also decreased with increasing carbohydrate coverage, but the corresponding adhesion between lactosyl ceramide-containing membranes increased with increasing amounts of glycosphingolipid in them. The nonspecific van der Waals forces accounted for the attraction measured in the control experiments and that between identical 10 mol % LacCer bilayers. However, the increase in the adhesion with increasing glycolipid density was 2-4 times greater than predicted by Lifschitz theory. Additionally, the forces measured during separation of membranes containing 20 and 30 mol % glycosphingolipid indicated that the headgroups bind and rearrange during bilayer detachment. The interactions between the carbohydrates are weak and apparently dynamic, and they generate an additional density-dependent intermembrane attraction that is on the order of the van der Waals force.