Welfare of calves - 2. Increase in vertebral artery blood flow following exsanguination by neck sticking and evaluation of chest sticking as an alternative slaughter method

The role of the vertebral arteries in delaying loss of sensibility following neck sticking in slaughter calves was investigated. Vertebral artery blood flow was measured using probes before, during and after electrical stunning and slaughter. Systemic blood pressure, electrocorticogram, visually evoked responses and the occurrence of carotid occlusions were also recorded. When carotid occlusion occurred, the time to onset of brain failure was delayed based on the development of an isoelectric state. In addition, when carotid occlusion occurred the mean arterial blood pressure was sustained for longer following slaughter, and concurrently vertebral artery blood flow could be maintained at about 30% of its initial level for up to 3 min. In some animals vertebral artery flow increased substantially following sticking. When chest sticking was used no occlusion of vessels occurred, mean arterial blood pressure fell promptly (within 8 s) and the onset of an isoelectric state did not extend beyond one minute. In addition, visually evoked responses were not present after 5 s following chest sticking.     

Dynamic fatigue of brittle materials containing indentation line flaws

A study is made of the dynamic fatigue response of brittle materials containing indentation-induced line flaws. The theoretical fracture mechanics of median crack evolution to failure under applied tension are first developed, with special emphasis on the role of residual contact stresses. In particular, it is shown that use of fatigue curves to evaluate the exponent in an assumed power-law crack velocity function may result in systematic error, by as much as a factor of two, if proper account is not taken of this residual contact contribution. Data from strength tests on soda-lime glass bars in water, using a tungsten carbide cutting wheel to introduce the median pre-cracks, confirm the basic predictions. The results suggest that extreme care needs to be exercised when using surfaces with a contact history, e.g. as with machining damage, in fatigue test programmes for materials analysis.     

Influence of maternal bodyweight on size, conformation and survival of newborn lambs

Although body condition score was not significantly different between light (<55 kg, n = 6) and heavy (> or =60 kg, n = 7) ewes at mating, it declined between Day 30 and Day 90 of gestation in light but not heavy ewes, and remained lower up to term. All ewes bore twins, delivered near term (Days 144-146) by Caesarean section. One lamb was immediately placed into a warm (30 degrees C; WD) and its twin into a cool (15 degrees C; CD) ambient temperature, and tissues were sampled at 0.5 h or 6 h. All CD lambs born to light ewes exhibited hypothermia and/or respiratory failure and did not survive longer than 30 min; these symptoms were not observed in their WD twins or any lamb born to heavy ewes. Total lamb birth weight, placental weight and fetal cotyledonary weight were lower with light than with heavy ewes. Lambs born to light ewes had less perirenal adipose tissue and smaller liver, heart, kidneys, brain, adrenals and thyroid, although their heart, brain and pancreas represented a larger proportion of total bodyweight; pancreas weight was similar to that in lambs born to heavy ewes. Hence, maternal bodyweight critically influences placental weight and lamb size and survival after birth.     

Dendritic Cells and Multiple Sclerosis: Disease,Tolerance and Therapy

Multiple sclerosis (MS) is a devastating neurological disease that predominantly affects young adults resulting in severe personal and economic impact. The majority of therapies for this disease were developed in, or are beneficial in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. While known to target adaptive anti-CNS immune responses, they also target, the innate immune arm. This mini-review focuses on the role of dendritic cells (DCs), the professional antigen presenting cells of the innate immune system. The evidence for a role for DCs in the appropriate regulation of anti-CNS autoimmune responses and their role in MS disease susceptibility and possible therapeutic utility are discussed. Additionally, the current controversy regarding the evidence for the presence of functional DCs in the normal CNS is reviewed. Furthermore, the role of CNS DCs and potential routes of their intercourse between the CNS and cervical lymph nodes are considered. Finally, the future role that this nexus between the CNS and the cervical lymph nodes might play in site directed molecular and cellular therapy for MS is outlined.     

Adipose tissue development during early postnatal life in ewe-reared lambs

This study examines the precise time course that brown adipose tissue (BAT) takes to adopt the characteristics of white adipose tissue in postnatal lambs. Perirenal adipose tissue was sampled from ewe-reared lambs within 1 h of birth and at 1, 2, 4, 7, 14, 21 and 30 days of age and analysed for the amount of mRNA for uncoupling protein (UCP), the amount and activity of UCP, and protein, mitochondrial protein and lipid content. This was combined with measurements of colonic temperature and jugular venous plasma concentrations of thyroid hormones and insulin-like growth factor-1 (IGF-1). Over the first 4-7 days of age, large quantities of UCP mRNA were associated with a peak in plasma triiodothyronine concentration at 2 days of age followed by a maximal amount and activity of UCP at 4 days and a basal colonic temperature of 39.3 degrees C. Between 7 and 30 days there was a large increase in lipid deposition as the amount and activity of UCP and the amount of UCP mRNA declined to basal values and colonic temperature was maintained at 40 degrees C. A significant positive relationship between perirenal adipose tissue lipid content and plasma IGF-1 concentration was observed throughout the study period. It is concluded that ovine adipose tissue maturation occurs in two distinct phases over the first month of life. The precise time scale of this process could be regulated in part by the lamb's body temperature which determines whether adipose tissue is required for heat production (i.e. BAT) or as an endogenous energy source (i.e. white adipose tissue).     

Extended energy approach to chaotic elastic-plastic response to impulsive loading

The paper supplements and extends an energy approach which helps to interpret elastic-plastic dynamic responses of a two-degree-of-freedom beam model whose ends are fixed, so that shallow arch action prevails, and chaotic as well as quasi-periodic vibrations may occur. For a problem of short pulse loading, a characteristic diagram is derived in which the energies at the stationary points (equilibria) of the elastic strain energy function V(w₁, w₂) are plotted against the pulse force, taken as the single loading parameter of the problem. Here w₁, w₂ are the displacements, and the function V contains the set of plastic strains as parameters, generated during the response. An alternative viewpoint is also introduced in which the plastic strains and the total available energy are regarded as specified parameters, and the problem is one of elastic response to arbitrary initial values of displacements and velocities.     

Interstitial iridium-192 implantation combined with external radiotherapy in anal cancer: ten years experience

BACKGROUND: The Quebec Neuroblastoma Screening (QNS) Project completed a 5-year program for measuring urinary vanillylmandelic acid (VMA)/homovanillic acid (HVA) levels at age 3 weeks and/or 6 months in 89% of 476,603 Quebec-born infants from 1989-1994; 45 screening positive preclinical cases (S-positive cases) and 20 congenital/neonatal (C/N) cases were identified. As of April 1997, an additional 59 cases in the same birth cohort were diagnosed clinically; these neuroblastomas developed after screening verified normal VMA/HVA levels (S-negative cases). METHODS: Pathology specimens from 45 of 59 S-negative cases were reviewed centrally and classified according to the Shimada system. Results were compared with clinical data and also with S-positive and C/N cases. RESULTS: Of 45 S-negative cases, 27 tumors had favorable histology (FH) and 18 had unfavorable histology (UH). Approximately 52% of FH tumors were diagnosed before age 1 year, whereas UH tumors were nearly exclusively (94%) diagnosed after age 1 year (P < 0.01). Approximately 89% of FH tumors were Stage I, II, or IV-S, whereas 72% UH tumors were Stage III or IV (P < 0.001). All children with FH tumors were alive at last follow-up (range of follow-up period: 9-79 months; median, 35 months), whereas 8 children with UH tumors died of disease even after limited follow-up (range of follow-up period: 0-60 months; median, 20 months). By contrast, S-positive and C/N cases were predominantly (97%) FH tumors, often (76%) Stage I, II, or IV-S, with excellent clinical outcome (survival rate of 98%). CONCLUSIONS: The majority of the UH neuroblastomas that developed in the birth cohort of the QNS Project were included in the group of S-negative cases and could not be detected by the screening at age 3 weeks and/or 6 months.     

Second malignancies in cervical cancer patients in the west of Scotland

A recent focus in health care is to develop a seamless transition for patients between the variety of health care agencies with whom they interact. The continuum of care for patients with stroke is complex and many levels of care are required, from acute intervention through to rehabilitation and reintegration into the community. A group of nurses from a variety of agencies in Southwestern Ontario received funding from the Ontario province Wide Nursing Project to effect a desirable change in the way nurses care for the stroke patient. This article describes the Ontario Province Wide Nursing project and the process of and challenges in developing a nursing model for stroke. The development of a nursing model for stroke patients and their families involved conducting nursing, and patient and family focus groups to identify key issues. Thirty-eight nurses participated in the nursing focus groups, and 8 patients and 18 family members participated in the patient and family focus groups. The common themes were the need for improved communication and the need to better prepare patients and families for the many transitions they experience during their recovery from stroke. A Stroke Education Record, which identifies a comprehensive list of potential learning needs of stroke patients and their families, and a Stroke Education and Resource Guide, which provides a reference for nurses, were developed and will be implemented in September 1998. Implementation of the model included a workshop, staff inservices, a self-learning package, and unit displays. Evaluation of the model will include nursing and patient and family focus groups, a chart review, written nursing evaluations, and patient and family telephone interviews.