547 research outputs found
Spinothalamic tract neurons in laminae I, III and IV of the rat: a retrograde neuronal tracing study
Ascending pathways in the spinal cord are very important in transmitting sensory information from the periphery to the higher brain centres. The spinothalamic tract represents an important component of these ascending pathways, and it has been traditionally described as the main pathway for conveying nociceptive and thermoceptive information. Spinothalamic neurons are widely distributed within the grey matter. Lamina I represents an important nociceptive zone and provides a significant source of projection neurons, some of which project to the thalamus. A projection from cervical superficial dorsal horn to the posterior triangular thalamic nucleus (PoT) in the rat has recently been identified. The PoT is located at the caudal end of the thalamus and was not included in injection sites in many previous quantitative retrograde tracing studies of the spinothalamic tract. Therefore, one of the reasons to conduct the present study was to estimate the number of the spinothalamic cells in lamina I in rat cervical and lumbar enlargements following injections that target the PoT with or without other thalamic nuclei known to receive input from lamina I. Neurons in this lamina are also known to project to the lateral parabrachial nucleus (LPb) and the periaqueductal grey matter (PAG). Other aims of the study were to quantify neurons in lamina I in the cervical enlargement that project to the LPb and PAG, to determine the proportion of lamina I spinothalamic neurons in lumbar and cervical enlargements that could be labelled from LPb and PAG, and to investigate morphological differences between different projection populations. Recent investigations have identified a group of neurons in lamina I of rat lumbar spinal cord that had large numbers of puncta that were immunoreactive for the glycine receptor-associated protein, gephyrin, and have a very high density of input from glutamatergic axons that contain vesicular glutamate transporter 2 (VGLUT2). These "large gephyrin-coated cells" in the lumbar cord are known to project to the LPb, but it is not yet known whether they project to thalamus and PAG. Therefore, another aim was to determine whether these cells project to these areas and also to analyse the projection pattern of cells of this type in the cervical enlargement.
Previous studies have identified a population of large neurons in laminae III and IV of rat spinal cord that express the neurokinin 1 receptor (NK1r) and have prominent dorsal dendrites that enter the superficial laminae. A substantial body of evidence points to the involvement of this population of cells in processing various types of noxious stimulus. Neurons of this type in lumbar enlargement are projection cells and form a major route through which nociceptive information reaches the brain. The proportion of these neurons that project to thalamus was not previously known, and the projection pattern of cells of this type in cervical enlargement has not yet been investigated. Therefore, an additional aim was to elucidate more on the projection patterns of these cells in both enlargements.
Various tracers (cholera toxin B subunit, Fluorogold or fluorescent latex microspheres) were injected stereotaxically into thalamus (25 rats), into thalamus and LPb (3 rats), or into thalamus and PAG (4 rats). Rats were perfused after three days and sections from the spinal cord (cervical and lumbar enlargements) were processed immunocytochemically to reveal tracer(s) in lamina I and lamina III/IV neurons, the NK1r, neuronal nuclei and, in some cases, the glycine receptor-associated protein gephyrin. Sections from brains were processed to visualise the injection sites.
Results of this study showed that: 1) most lamina I spinothalamic neurons in the C7 and L4 segments could be labelled from injections centred on the PoT; 2) the estimated total numbers of spinothalamic cells in lamina I on the contralateral side of the C7 and L4 segments are 91 and 16 cells, respectively, and this constitutes 2-3% and 0.2% of the total neuronal population in lamina I in the C7 and L4 segments, respectively; 3) the C7 segment contained fewer lamina I spinoparabrachial cells, but a similar number of spino-PAG cells, compared to L4; 4) virtually all spinothalamic lamina I neurons at both cervical and lumbar levels were labelled from LPb and between a third and a half were labelled from PAG; 5) spinothalamic lamina I neurons differed from those labelled only from LPb in that they were generally larger, more often multipolar and (in cervical enlargement) had stronger NK1r-immunoreactivity; 6) ~39% of "large gephyrin-coated cells" in L5 project to the thalamus and this accounts for ~21% of the total thalamic projection from lamina I in this segment, even though these cells constitute only ~2.5% of projection neurons in lamina I; 7) the great majority of "large gephyrin-coated cells" in C6 project to thalamus and LPb, and at both segmental levels, some project to both of these areas; 8) only few "large gephyrin-coated cells" in L5 and some of those in C6 project to PAG; 9) ~84% of the lamina III/IV NK1r-immunoreactive neurons in C6 and C7 and 17 28% of those in L4 and L5 belong to the spinothalamic tract, and these apparently project exclusively to the caudal thalamus, including PoT; 10) most of the large NK1r-immunoreactive lamina III/IV cells at both levels project to LPb, but few were labelled from PAG, and at both segmental levels, some project to both thalamus and LPb.
Findings from the present study indicate that the PoT is one of the major targets for neurons in lamina I as well as to the population of the NK1r-immunoreactive neurons in laminae III and IV. Since the PoT projects to the second somatosensory and insular cortices, the present results suggest that these are major targets for information conveyed by both these populations of spinothalamic neurons. In addition, these results confirm that projection neurons have extensive collateral projections, and suggest that different sub-populations of lamina I cell have characteristic patterns of supraspinal projection
Nutrient Chemo Prevent to Enhance Cancer Prevention: A Review
Introduction: Nutrients Chemoprevention is dietary compounds to reduce the incidence of cancer, and the dietary compounds could be fibers, nutrients, or vitamins.Purpose: the aim of this integrative literature review to determine effect of nutrients chemo-prevents to reduce risk of cancer.Design: integrative literature review.Method: the electronic databases of CINAHL with full text MEDLINE with full text for article published between 2009 and 2014.Finding: most of nutrients chemo prevents reduce risk some type of cancer. Conclusion: review the nutrients chemo prevents enhance cancer prevention and reduce risk of cancer, so all of country's must be educate the people about the important the nutrition to prevent cancer and enhance health care provider to apply this finding when they make education for the patient or clients, and this topic need more study to become evidence based practice. Keywords: Chemo Prevent, Cancer Prevention, Dietary Intake
Review of magnetohydrodynamic pump applications
AbstractMagneto-hydrodynamic (MHD) principle is an important interdisciplinary field. One of the most important applications of this effect is pumping of materials that are hard to pump using conventional pumps. In this work, the progress achieved in this field is surveyed and organized according to the type of application. The literature of the past 27years is searched for the major developments of MHD applications. MHD seawater thrusters are promising for a variety of applications requiring high flow rates and velocity. MHD molten metal pump is important replacement to conventional pumps because their moving parts cannot stand the molten metal temperature. MHD molten salt pump is used for nuclear reactor coolants due to its no-moving-parts feature. Nanofluid MHD pumping is a promising technology especially for bioapplications. Advantages of MHD include silence due to no-moving-parts propulsion. Much progress has been made, but with MHD pump still not suitable for wider applications, this remains a fertile area for future research
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An empirical study of human resources management practices in domestic and multinational enterprises in the kingdom of Saudi Arabia
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThis study was undertaken with the objective to understand Strategic Human Resource Management (SHRM) practices in domestic enterprises (DEs) vs multinational enterprises (MNEs) in the country context of the Kingdom of Saudi Arabia (KSA). The literature suggested that there would be a number of important differences in core HR practices, such as recruitment, retaining, retention and compensation when it comes to executing these within the domestic and multinational work environment of business enterprise. Sixteen (16) testable hypotheses were drafted after scanning the literature on the subject; these were then put to test with the help of primary data collected from 255 firms, two-thirds of which were DEs whilst the remaining one-third were MNEs. Data that were analysed with the help of parametric and non-parametric tests revealed several interesting facts. The study found that differences do exist in the recruitment, training and compensation practices between the two modes of enterprise. Results in particular showed that MNEs were much more stringent in their recruitment practices than DEs; DEs were found to be more concerned with the formal qualifications of candidates than MNEs. The turnover rates of employees in DEs hired on the basis of personal characteristics were greatest, whereas it was lower in the context of MNEs. Interestingly, larger sized DEs did not worry about the personal characteristics of candidates during the selection process. Firms in oil and petrochemical MNEs were more likely to recruit employees with higher personality. On the whole, the results confirm that MNEs in Saudi faced lower employee turnover rates than DEs operating in the same context. Additionally, the results confirmed that MNEs followed better HR practices than DEs, spanning recruitment and selection policies, better training systems, better performance appraisal systems, and more structured incentives and rewards system. This is one of a few studies conducted in the context of a non-Western environment and points out a number of policy implications and future avenues of research. With respect to normative theory, the point is argued that those organisations with a set of best HRM practices would achieve greater performance outcomes, regardless of the organisational behaviour of the firms or the environment of the host country. However, the findings confirmed that part of the HRM practices were affected by the behaviour of firms during the process of the organisation moving to the global market. Furthermore, convergence theories argue that HRM practices will be the same, behaviourally, throughout the process of transferring from home country to host country. The results of the current research indicate that some HRM practices will be different during the process of transferring from the original country to the host country due to various factors, such as strength of cultural behaviour in Saudi Arabia, and competitors in the host country. For instance, the Saudi Labour Office Law requires that MNEs hire local employees, meaning that the recruitment process will be simple and not difficult in some regards, with employees able to meet the requirements of government regulations. The government of Saudi Arabia has forced MNEs to follow up the ‘Nitaq’ and ‘Saudisation’ system, which has argued that MNEs must recruit local employees. The findings also support convergence theories that state HRM practices as being the same during the process of transferring to Saudi Arabia. This convergence is required to fit the local context for the importance of local firms. Local firms can learn of the benefits to be garnered from the HRM practices of MNEs. As an example, the findings show that MNEs have a low turnover and high productivity of employees due to MNEs utilising appraisal, training and incentives. MNEs’ HRM practices in Saudi Arabia adopt duality theories that argue some practices as convergence whereas others HRM are divergence
Arab Women's Breast Cancer Screening Practices: A Literature Review
Breast cancer incidence and mortality rates are increasing in the Arab world and the involved women are often diagnosed at advanced stages of breast cancer. This literature review explores factors influencing Arab women’s breast cancer screening behavior. Searched databases were: Medline, PubMed, Cochrane Database of Systematic Reviews, CINAHL Plus, Google Scholar, Index Medicus for WHO Eastern Mediterranean, and Asian Pacific Journal of Cancer Prevention. Breast cancer screening participation rates are low. Screening programs are opportunistic and relatively new to the region. Knowledge amongst women and health care providers, professional recommendation, socio-demographic factors, cultural traditions, beliefs, religious, social support, accessibility and perceived effectiveness of screening influence screening behavior
Arab female and male perceptions of factors facilitating and inhibiting their physical activity: Findings from a qualitative study in the Middle East
Objectives: Physical inactivity is a leading global risk to health by contributing to obesity and other chronic diseases. Many chronic non-communicable diseases, such as cancer, diabetes, and cardiovascular diseases (CVDs), can be prevented and controlled by modifying lifestyle behaviors such as physical activity [PA]. However, prevalence of insufficient physical activity and obesity is high in the Middle East Region. In Qatar, the incidence rates of CVDs, diabetes, colon, and breast cancer have been rising rapidly. The purpose of this study was to explore facilitators and barriers influencing PA of adult Arab men and women living in Qatar and to understand what they think would be helpful to increase PA. The goal of the research is to identify culturally appropriate and effective interventions that improve the health of Arab population. Design: Using the socioecological model as the theoretical framework, we conducted an exploratory qualitative study with 128 Arab adult men and women living in Qatar. We utilized focus group interviews to collect the data and performed thematic analysis to generate themes. Results: At the individual level, perceived benefits of PA, presence of diseases, person’s will, motivation and goals, and time to exercise influenced the individual’s PA. At the sociocultural level, religious teachings of Islam, cultural, attitude, beliefs, and practices, and informal support influenced the participants’ PA. At the organizational and political level, physical environment to exercise, accessibility of facilities, organizational support, and health information about PA influenced their PA. Conclusion: Arab men and women are aware of the importance and benefits of PA. They have the motivation to be physically active, but in the absence of supportive environment, their knowledge might not translate into action. Creating supportive environments at multiple levels that are conducive to PA is warranted
A Retrospective Study of Non-Communicable Diseases amongst Blue-Collar Migrant Workers in Qatar
BACKGROUND:
South Asian workers have a greater predisposition to non-communicable diseases (NCDs) that is exacerbated by migration and length of residence in host countries. Aims: To examine the association between length of residence in Qatar with diagnosis of NCDs in male blue-collar workers.
METHODS:
A retrospective investigation of the electronic health records (EHRs) of 119,581 clinical visits by 58,342 patients was conducted. Data included age, nationality and confirmed ICD-10 diagnosis. Based on duration of residence, the population was divided into groups: ≤6 months, 6–12 months, 1–≤2 years, 2–≤5 years, 5–≤6 years, >6 years. It was assumed that the group that had been resident in Qatar for ≤6 months represented diseases that had been acquired in their countries of origin. Results: South Asian (90%) patients presented with NCDs at a younger (mean ± SD age of 34.8 ± 9.0 years) age. Diabetes and hypertension were higher in those who had just arrived (<6 months’ group), compared to the other durations of residence groups. Conversely, acute respiratory infections, as well as dermatitis and eczema, all increased, perhaps a consequence of shared living/working facilities. Only patients with diabetes and hypertension visited the clinic multiple times, and the cost of medication for these NCDs was affordable, relative to earnings.
DISCUSSION/CONCLUSIONS:
Blue-collar workers were predominantly South Asian, from lower socioeconomic classes, with early onset chronic NCDs. Notably, residence in Qatar gave them better access to affordable, significantly subsidized healthcare, leading to effective management of these chronic conditions
Lessons from the recent case of CO poisoning due to shisha (hookah, narghile) tobacco smoking in Singapore
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