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Biomedical subjects

K A Long

Publications and source records attributed to K A Long.

At least 19 recordsLinked to original sources
PubMed2001

Vaccination of boars with a GnRH vaccine (Improvac) eliminates boar taint and increases growth performance.

Peri- and postpubertal boars accumulate substances (e.g., androstenone and skatole) in their fatty tissue that are responsible for boar taint in pork. The objective of this study was to assess the efficacy of a GnRH vaccine, Improvac, in eliminating boar taint. Three hundred male (200 intact boars, 100 barrows) crossbred (Large White x Landrace) pigs were used in a 2 x 3 factorially arranged experiment. The respective factors were sex group (barrows, boars treated with placebo, or boars treated with Improvac) and slaughter age (23 or 26 wk). Vaccines were administered 8 and 4 wk before slaughter. All Improvac-treated pigs exhibited anti-GnRH titers. Testes and bulbo-urethral gland weights in treated pigs were reduced by approximately 50% (P < 0.001) and serum testosterone levels were below 2 ng/mL in the majority of treated boars (94 and 92% across both age groups at 2 and 4 wk, respectively). Boar taint, as assessed by the concentration of androstenone and skatole in s.c. fat, was suppressed to low or undetectable levels in 100% of Improvac-treated boars. No Improvac-treated pigs had significant concentrations of either androstenone (> 1.0 microg/g) or skatole (> 0.20 microg/g). In contrast, 49.5% of placebo-treated controls had significant androstenone and 10.8% had significant skatole levels, resulting in 10% of the control boars with high concentrations of both compounds. The mean concentrations of taint compounds in the Improvac-treated pigs were not significantly different from those in barrows. Improvac-treated boars grew more rapidly (P = 0.051 and < 0.001 for pigs slaughtered at 23 and 26 wk of age, respectively) than control boars over the 4 wk after the secondary vaccination, possibly because of reduced sexual and aggressive activities. Compared with barrows, Improvac-treated boars were leaner and had superior feed conversion efficiency. The vaccine was well tolerated by the pigs, and no observable site reactions could be detected at the time of slaughter. Vaccination of boars with Improvac allows production of heavy boars with improved meat quality through prevention and control of boar taint.

Adipose Tissue↗
PubMed1998

Development of a PCR test based on a gene region associated with the pathogenicity of Pasteurella multocida serotype B:2, the causal agent of haemorrhagic septicaemia in Asia.

We have developed a PCR assay to detect Pasteurella multocida serotype B:2, the causal agent of Haemorrhagic Septicaemia (HS) in Asia. Nucleotide sequence determination of a 16S rRNA-23S rRNA PCR product unique to B:2 strains was shown to share amino acid sequence homology with a bacteriophage Mu protein. Primers designed from this sequence when tested against a panel of isolates recovered from a wide geographical area and representing a large range of bacterial genera and species, were found to specifically amplify DNA from P. multocida, serotype B:2. Southern hybridisation confirmed the presence of this sequence in only the B:2 serotype of P. multocida, suggesting an association between bacterial virulence and the presence of bacteriophage genes in the bacterial genome. The results of this study demonstrate the potential application of PCR to the diagnosis of HS in cattle and buffalo in Asia. Application of PCR to support diagnosis of HS will greatly improve accuracy, laboratory response time, and will facilitate rational deployment of resources for controlling this disease.

Animals↗
PubMed1998

The specificity of antibody in chickens immunised to reduce intestinal colonisation with Campylobacter jejuni.

Poultry consumption has been identified as a major risk factor for human infection with Campylobacter jejuni in developed countries. C. jejuni is present in the gastrointestinal tract of broiler chickens at the time of slaughter, and faecal contamination of carcases during processing results in significant campylobacter loads on carcases. One approach to reducing the level of carcase contamination with C. jejuni is to control campylobacter infection in broiler chickens. To this end, the study described here investigated the specificity of antibody in serum and intestinal secretions of chickens that had been immunised with campylobacter antigens and then challenged with viable bacteria. The immunodominant antigens in the serum of birds that showed a 2-log reduction in caecal colonisation with C. jejuni included flagellin protein (61-63 Kd) and three additional antigens of 67, 73.5 and 77.5 Kd. Only flagellin and the 67 Kd antigen were recognised by IgG antibody in gastrointestinal secretions of the same birds. Antibody from chickens immunised with purified native flagellin protein recognised flagellin protein and the 67 Kd antigen in Western blots probed with serum, but only the flagellin proteins (61-63 Kd) in Westerns probed with gastrointestinal secretions. Analysis of the specificity of the response to flagellin protein using recombinant clones that expressed regions of the flagellin gene suggests that epitopes in each region of the flagellin protein were immunogenic. Of the immunodominant antigens, only flagellin appeared to be surface-exposed on viable C. jejuni, although conformational epitopes of flagellin appeared to be sensitive to the method of antigen purification. The results of this study suggest that flagellin and possibly the 67 Kd antigen may be valuable for immunological control of intestinal infection with C. jejuni in chickens, but that further work is required to purify these as vaccine candidates by using methods that preserve conformational epitopes.

Animals↗
PubMed1998

Health care for the school-age child.

The research related to health care for school-age children is reviewed. Two major categories are considered, namely, health-risk behavior and psychosocial health. Research related to the emerging issues of homelessness and AIDS is also reviewed. The research completed to date on school-age children's health care is critiqued with an emphasis on the state of the science in nursing. Recommendations for further research are provided.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Genotypic Diversity among Campylobacter jejuni Isolates in a Commercial Broiler Flock.

Analysis of nucleic acid polymorphism in the flagellin genes of Campylobacter jejuni was used to investigate genetic diversity among Campylobacter spp. in a commercial broiler flock. Three hundred single colonies of C. jejuni were isolated from fecal samples collected weekly for 3 weeks immediately before slaughter. Both the flaA and flaB genes were amplified by PCR, and the PCR product was digested with the restriction enzyme AluI. The fragments generated were then analyzed by agarose gel electrophoresis. Among the 300 recovered isolates, five different restriction fragment length polymorphism profiles were observed. Three of these profiles were dominant during the course of the study, and the other two profiles were detected at low frequency. Analysis of genetic variation in C. jejuni over the course of an experimental infection lasting 7 weeks indicated that there was no obvious drift in the flagellin gene type. These findings demonstrate that a range of bacterial genotypes can constitute the bacterial population within a commercial poultry flock, with the most likely sources of these types being multiple environmental exposure and/or genetic drift within the population. This degree of diversity must be considered in epidemiological analyses which utilize genetic typing methods that investigate Campylobacter contamination of any food source, including poultry, to ensure that the total gene pool for C. jejuni is evaluated.

Journal Article↗
PubMed1997

The relationship between maximal expiratory flow and increases of maximal exercise capacity with exercise training.

We previously reported that patients with mild to moderate airflow limitation have a lower exercise capacity than age-matched controls with normal lung function, but the mechanism of this reduction remains unclear (1). Although the reduced exercise capacity appeared consistent with deconditioning, the patients had altered breathing mechanics during exercise, which raised the possibility that the reduced exercise capacity and the altered breathing mechanics may have been causally related. Reversal of reduced exercise capacity by an adequate exercise training program is generally accepted as evidence of deconditioning as the cause of the reduced exercise capacity. We studied 11 asymptomatic volunteer subjects (58 +/- 8 yr of age [mean +/- SD]) selected to have a range of lung function (FEV1 from 61 to 114% predicted, with a mean of 90 +/- 18% predicted). Only one subject had an FEV1 of less than 70% predicted. Gas exchange and lung mechanics were measured during both steady-state and maximal exercise before and after training for 30 min/d on 3 d/wk for 10 wk, beginning at the steady-state workload previously determined to be the maximum steady-state exercise level that subjects could sustain for 30 min without exceeding 90% of their observed maximal heart rate (HR). The training workload was increased if the subject's HR decreased during the training period. After 10 wk, subjects performed another steady-state exercise test at the initial pretraining level, and another maximal exercise test. HR decreased significantly between the first and second steady-state exercise tests (p < 0.05), and maximal oxygen uptake (VO2max) and ventilation increased significantly (p < 0.05) during the incremental test, indicating a training effect. However, the training effect did not occur in all subjects. Relationships between exercise parameters and lung function were examined by regression against FEV1 expressed as percent predicted. There was a significant positive correlation between VO2max percent predicted and FEV1 percent predicted (p < 0.02), and a negative correlation between FEV1 and end-expiratory lung volume (EELV) at maximal exercise (p < 0.03). There was no significant correlation between FEV1 and maximal HR achieved during exercise; moreover, all subjects achieved a maximal HR in excess of 80% predicted, suggesting a cardiovascular limitation to exercise. These data do not support the hypothesis that the lower initial VO2max in the subjects with a reduced FEV1 was due to deconditioning. Although increased EELV at maximal exercise, reduced VO2max and a reduced VO2max response with training are all statistically associated with a reduced FEV1, there is no direct evidence of causality.

Case-Control Studies↗
PubMed1997

Advanced education for the role of rural nurse generalist.

The Montana State University College of Nursing has developed a master's degree program which prepares nurses as generalists with advanced knowledge for understanding and addressing rural health care needs. The programs is clear about its goals and objectives and does not attempt to be "all things for all people." The emphasis is on rural nursing, and this emphasis is present in recruiting, teaching, research and publication at the College. Classroom and clinical experiences challenge students to develop a broad range of skills, and most importantly to enhance critical thinking and problem-solving abilities. Since delivering high quality health care in rural areas requires the ability to understand health care from the consumer's perspective, both data collection and clinical experience in rural communities are required. The enthusiasm for rural nursing--practice, teaching and research--displayed by faculty members, alumnae and students is both a major factor in, and an indication of, the program's success.

Clinical Competence↗
PubMed1996

Immunisation of chickens to reduce intestinal colonisation with Campylobacter jejuni.

1. Systemic and intestinal antibody titres were measured in chickens following subcutaneous, intraperitoneal (i.p.), oral (p.o.) and combined i.p./p.o. administration of antigen, in soluble, emulsified or microparticulate form. Antigens tested included keyhole limpet haemocyanin (KLH), killed Campylobacter jejuni whole cells and purified campylobacter flagellin protein. 2. The effect of immunisation with purified flagellin protein or with killed C. jejuni whole cells in reducing intestinal colonisation was assessed. The ability of newlyhatched chicks to respond to immunisation was limited, possibly because of the immaturity of the immune system rather than maternal suppression of an immune response. Only 5 to 13 birds that were first immunised when 1-d-old with KLH showed a systemic response, even after 4 immunisations, whereas 10 of 11 birds that were first immunised at 24 d-old responded systemically. 3. In an immunisation and challenge experiment, birds that were immunised twice intraperitoneally, at 16 and 29 d-old, with killed C. jejuni whole cells, had fewer C. jejuni, in the caecal contents than unimmunised control birds. This reduction in intestinal colonisation, to less than 2% of bacterial numbers in control birds, was associated with an increase in specific IgG in intestinal secretions. There was no significant increase in specific IgA or IgM in intestinal secretions following immunisation and challenge. 4. These results indicate that immunisation can reduce the level of intestinal infection with C. jejuni. The protection may be enhanced by developing improved methods of immunisation that stimulate production of increased titres of specific antibody in intestinal secretions, particularly specific IgA antibody.

Animals↗
PubMed1995

Variations in bone status of contralateral and regional sites in young athletic women.

To determine if volleyball (VB), basketball (BB), soccer (SO) and swimming (SW) programs were associated with site-specific differences in contralateral, regional, and total body bone mineral density (BMD), 62 eumenorrheic female athletes [BB (N = 7), VB (N = 11), SO (N = 9), and SW (N = 7)] and controls participated in the study. The controls were categorized as either moderately active control (MOD) (N = 17) or sedentary control (SED) (N = 11) based on fitness and activity assessments. Contralateral, total body, lumbar (L2-L4), and femur BMD were measured (Lunar DPX). The between sport contralateral comparisons indicated that VB and BB had significantly greater leg and arm measurements than all other groups, while the within contralateral comparisons revealed significantly greater right arm measurements for all groups, except SW. No significant differences were found for the within group contralateral leg comparisons, except VB. VB and BB had significantly higher (P < or = 0.05) total body and lumbar BMD values than SW, MOD, and SED. At the femur neck, trochanter, and Ward's triangle, BB showed significantly higher BMD than SW, MOD, and SED. Only BB had significantly higher Ward's triangle BMD than SW, MOD, and SED. Our findings show site-specific differences in BMD associated with selected sports' programs.

Absorptiometry, Photon↗
PubMed1994

Molar function depends on molecular structure of behavior.

Pigeons chose between green side keys, then waited a shorter or longer time before pecking a center key, and finally chose between red side keys. Two successive left choices (to green and then red) with a shorter wait intervening, or 2 successive right choices with a longer wait intervening, were intermittently reinforced with food. The 2 required waiting times and the relative frequency of reinforcement for the shorter reinforced pattern were varied. Molar preference, defined in terms of coherent responses that satisfied the molecular reinforcement contingency, conformed to the highly adaptive matching level, but molar preference, defined in terms of incoherent responses, did not. The molar matching result therefore generalizes to responses with complex molecular structures provided that analyses distinguish between coherent and incoherent responses. The results are compatible with the idea that awareness can facilitate adaptation.

Animals↗
PubMed1993

Comparison of metabolic and perceptual responses during maximal exercise on two ergometers: NOVA 5000 vs treadmill.

The purpose of this study was to investigate the physiological and perceptual responses to exercising on the NOVA 5000 (NO). The NO is a new computer controlled multi-limb exercise device which allows the exerciser to work arms and legs individually or in any combination from a seated position. Eleven subjects (7 males, 4 females) participated in two sessions of graded exercise testing (GXT) within the same week. One session involved a GXT treadmill test (TR) to exhaustion utilizing the Bruce protocol. A second GXT was performed on the NO that utilized a protocol consisting of successive 3 minute stages starting at 50 watts and increasing 25 watts until exhaustion. A Quinton Q-5000 and a Sensor Medics metabolic cart monitored cardiorespiratory function during both tests. MANOVA analysis revealed no significant (p < 0.05) differences between the NO and TR maximal values for VO2 (1.min-1 and ml.kg-1.min-1), HR, RER, VE, and workload (WR). There were significant (p < 0.05) differences between the to modes of testing for RPE and TT (time on task) with the NO having significantly higher values on both variables. The correlation coefficient for the VO2max values on the TR vs NO was r = 0.97. When the HR and VO2 means from each stage of the NO GXT were correlated over the duration of the test, a positive correlation (r = 0.99) was obtained. The results of this study indicate that the NOVA 5000 may be a suitable alternative device for testing healthy adults.

Adult↗
PubMed1993

The concept of health. Rural perspectives.

An understanding of the client's concept of health is necessary to conduct relevant and effective health assessment, planning, intervention, and evaluation. Client health concepts are affected by place of residence and further colored by specific community and individual level variations including occupation, education, subculture, age, gender, and health status. Rural nursing practice can be improved through knowledge of the health perceptions and definitions held by the rural clients to be served. Nursing, as a discipline, has traditionally emphasized the need to understand the client's perspective and to develop mutually agreed on health goals in collaboration with the client. Rural nursing practice offers unique opportunities to consider meanings of health within the environmental context. Further, it challenges nurses to work hand-in-hand with clients to develop strategies that fit the context, and thus effectively address rural health care needs.

Adult↗
PubMed1992

Descriptions and perceptions of health among rural and urban adults with multiple sclerosis.

The purpose of this study was to compare the health descriptions and perceptions of adults with multiple sclerosis living in rural and urban areas. Data were obtained from 361 adults, who responded to a mail survey including standardized self-report measures of physical and mental health, disability and social support, and an open-ended question on the meaning of health. In contrast to findings with general, nonclinical populations, the health perceptions and descriptions of this chronically ill population were not significantly affected by their place of residence. Further research is needed to examine the applicability of health-related findings from general populations to persons who are chronically ill.

Adult↗
PubMed1991

The Masculinity-Femininity Scale of MMPI-2: is it useful with normal men?

Using ratings provided by significant others, we examined characteristics of 819 normal men whose scores on the Masculinity-Femininity scale (Scale 5) of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) ranged from low to high. Also examined were the possible effects of educational level as a moderator variable. Only one external characteristic was correlated with Scale 5 scores at a level of significance that could not be attributed to chance, and that correlation was negative, whereas previous literature indicated a positive relationship. The findings were essentially the same whether or not the effects of education were controlled. Regardless of Scale 5 scores and the higher the men's educational levels, the more positive were ratings by their partners. In general, the results do not support the usefulness of Scale 5 in describing the personalities and behaviors of normal men.

Adult↗
PubMed1989

Rural nursing: developing the theory base.

Many health care needs of rural dwellers cannot be adequately met through the use of existing nursing models alone but require unique approaches emphasizing the special needs of this population. The development of an integrated theory base for rural nursing is necessary. A retroductive approach, building upon both qualitative and quantitative research data, is being used to develop a theory of rural nursing. Key concepts identified are: work beliefs and health beliefs; isolation and distance; self-reliance; lack of anonymity; outsider/insider; and old-timer/newcomer. Implications for practice include the importance of relating health care to work practices and the need to intervene indirectly through established informal systems.

Attitude to Health↗