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Background: Studies have found that deaf individuals have higher rates of psychiatric disorder than those who are hearing, while at the same time encountering difficulties in accessing mental health services. These factors might increase the risk of suicide. However, the burden of suicidal behaviour in deaf people is currently unknown. The aim of the present review was to provide a summary of literature on suicidal behaviour with specific reference to deaf individuals. The objectives of the review were to establish the incidence and prevalence of suicidal behaviour in deaf populations; describe risk factors for suicidal behaviour in deaf populations; describe approaches to intervention and suicide prevention that have been used in deaf populations., Methods: A number of electronic databases (e.g. Medline, PsycINFO, CINAHL, EMBASE, Dissertation Abstracts International, Web of Science, ComDisDome, ASSIA, Education Sage Full Text, Google Scholar, and the grey literature databases FADE and SIGLE) were explored using a combination of key words and medical subject headings as search terms. Reference lists of papers were also searched. The Science and Social Sciences Citation Index electronic databases were used to identify studies that had cited key papers. We also contacted experts and organisations with an interest in the field., Results: Very few studies focussed specifically on suicide in deaf populations. Those studies that were included (n = 13) generally involved small and unrepresentative samples. There were limited data on the rate of suicidal behaviour in deaf people. One study reported evidence of hearing impairment in 0.2% of all suicide deaths. Another found that individuals with tinnitus seen in specialist clinics had an elevated rate of suicide compared to the general population. The rates of attempted suicide in deaf school and college students during the previous year ranged from 1.7% to 18%, with lifetime rates as high as 30%. Little evidence was found to suggest that risk factors for suicide in deaf people differed systematically from those in the general population. However, studies did report higher levels of depression and higher levels of perceived risk among deaf individuals than hearing control groups. No firm evidence was found regarding the effectiveness of suicide prevention strategies in deaf people, but suggested strategies include developing specific screening tools, training clinical staff, promoting deaf awareness, increasing the availability of specialist mental health services for deaf people., Conclusion: There is a significant gap in our understanding of suicide in deaf populations. Clinicians should be aware of the possible association between suicide and deafness. Specialist mental health services should be readily accessible to deaf individuals and specific preventative strategies may be of benefit. However, further research using a variety of study designs is needed to increase our understanding of this issue.

A large percentage of lymphocytes in the blood of cattle express the gamma delta T-cell receptor, but specific functions for these cells have not yet been clearly defined. There is evidence, however, that human, murine, and bovine gamma delta T cells have a role in the immune response to mycobacteria. This study investigated the ability of bovine gamma delta T cells to expand and produce gamma interferon (IFN-gamma) in response to stimulation with mycobacterial products. Bovine gamma delta T cells, isolated from the peripheral blood of healthy cattle, expanded following in vitro stimulation with live mycobacteria, mycobacterial crude cell wall extract, and Mycobacterium bovis culture filtrate proteins. In addition, purified gamma delta T cells, cocultured with purified monocytes and interleukin-2, consistently produced significant amounts of IFN-gamma in response to mycobacterial cell wall. The IFN-gamma-inducing component of the cell wall was further identified as a proteolytically resistant, non-sodium dodecyl sulfate-soluble component of the mycolylarabinogalactan peptidoglycan.

Understanding the immunological function of bovine gammadelta T cells is essential for evaluating their role in the response to infectious agents and for determining the potential of targeting this population with vaccines. This study examined the age dependent changes of circulating CD2(+) and CD2(-) gammadelta T cells as well as differences in the expression of activation markers between these two populations. Changes in activation marker expression following vaccination with Vira Shield 5 are also discussed. CD62L was expressed on all CD2(-) gammadelta T cells but only a subset of CD2(+) gammadelta T cells and following vaccination there was a significant decrease in the percentage of CD2(-)/CD62L(+) gammadelta T cells but not CD2(+)/CD62L(+) gammadelta T cells. Both CD2(-) and CD2(+) gammadelta T cells consistently expressed high levels of CD44. The majority of both CD2(-) and CD2(+) gammadelta T cells also expressed CD45R, however, more of the CD2(-) cells were CD45R(neg/lo). Following vaccination there was a significant decrease in the percentage of CD2(-) and CD2(+) gammadelta T cells that expressed CD44 and CD45R. These data indicate significant differences in activation expression on CD2(-) and CD2(+) gammadelta T cells, which adds to the growing evidence that there may be functional as well as phenotypic differences between these two populations of bovine gammadelta T cells., (Copyright 2003 Elsevier Science Ltd.)

Although various members of the pattern recognition Toll-like receptor (TLR) family have been implicated in host resistance to Mycobacterium tuberculosis infection, it remains unclear if the TLR4 receptor plays an important role. We demonstrate here that infection of TRL4-competent and TLR4-deficient mice on the C3H inbred mouse strain background had similar outcomes, measured in terms of the course of the disease, cell accumulation patterns in the lungs, and lung histopathology. These data argue against a significant role for TLR4 in immunity to tuberculosis in the mouse model.

The progression of the immune response in the lungs after aerosol infection with Mycobacterium tuberculosis is a complex cellular event dominated by macrophages and lymphocytes. Although the phenotype of lymphocytes participating in this response is becoming increasingly well characterized, the dynamic influx of these cells during the infection and their spatial arrangements within the lung tissue are still poorly understood. This study shows that in the first month after aerosol infection with M. tuberculosis there was a steady increase in the percentages of total CD3+, CD3+ CD4+ and CD3+ CD8+ cells, with consistently larger numbers of CD3+ CD4+ cells than of CD3+ CD8+ cells. As granuloma formation continued, the granuloma was found to consist of macrophages, CD4, and CD8 T cells, as well as a smaller number of B cells. Whereas CD4 T cells formed organized aggregates, CD8 T cells were fewer and more scattered and tended to be more prominent toward the periphery of the granulomas. The possible ramifications of the juxtapositions of these two major T-cell subsets are discussed.

An 8-year-old, female llama was evaluated for nonhealing, ulcerative, cutaneous lesions, which also involved the mammary gland. Biopsies of the lesions distant from and within the mammary gland area revealed an aggressive carcinoma. The tumor was confirmed at necropsy to be a mammary gland adenocarcinoma with cutaneous metastasis.

A necessary role for cytotoxic T lymphocytes in protection against Mycobacterium tuberculosis (MTB) has been suggested by studies of the beta2-microglobulin-deficient mouse, which is unable to present antigens through MHC class I and class I-like molecules and invariably succumbs early after infection. To identify the relative contributions of distinct putative MHC class I-dependent cell populations in protection against tuberculosis, we compared a variety of gene-disrupted mouse strains for susceptibility to MTB infection. Among the strains tested, the most susceptible mice, as measured by survival time and bacterial loads, were the beta2-microglobulin(-/-), followed by transporter associated with antigen processing deficient (TAP1(-/-)), CD8alpha(-/-), perforin(-/-), and CD1d(-/-) mice. These findings indicated that (i) CD8(+) T cells contribute to protection against MTB, and their protective activity is only partially dependent on perforin; (ii) beta2-microglobulin-dependent T cell populations distinct from CD8(+) T cells also contribute to anti-MTB immunity; and (iii) protective immune mechanisms are predominantly TAP-dependent, although TAP-independent mechanisms also contribute to protection. Because CD1d-deficient animals were fully resistant to MTB, other TAP-independent mechanisms must contribute to protection. We suggest here that both classical and nonclassical MHC class I-restricted T cells, distinct from CD1d-restricted cells, may be involved in protective immune responses against tuberculosis.

Despite technical advances in the surgical treatment of infected wounds, this surgery remains a serious problem as it represents more than 27% of infection complications. In the majority of these operations, the wounds are left open and patients undergo long treatments of antibiotics. When the carbon dioxide laser technique was introduced in our country in 1984, it was tested using quantitative bacteriology: it was shown that when used on infected wounds, it reduced the bacterial population of these lesions to low levels with low tissue injury. At our center, between August 1984 and 1994, 539 patients with infected wounds were treated using a carbon dioxide laser. Out of 495 patients (91.84%) 1 patient was cured, 37 patients (6.86%) required more than one operation to be cured, and in 7 patients (1.30%) the treatment failed.