A multidisciplinary audit of patients' seating needs.

Although emphasis in the literature may be on the use of pressure-relieving mattresses and specialist beds, seating is also an important part of preserving tissue viability. A collaborative approach within the multidisciplinary team is of value. Equipment is of limited value if not complemented by best practice, carried out by well-educated staff. Patients' views should be elicited.

Determination of the Surface Isoelectric Point of Oxide Films on Metals by Contact Angle Titration

The surface isoelectric point for the native air-formed oxide films on aluminum, chromium, and tantalum has been determined by measurement of contact angles at the hexadecane/aqueous solution interface as a function of pH of the aqueous phase. Application of Young's equation, the Gibbs equation, and surface equilibria conditions for hydroxylated oxide films leads to a mathematical expression which shows that the contact angle goes though a maximum at the isoelectric point of the oxide. The experimentally determined isoelectric point of oxide-covered chromium is 5.2 to 5.3, of oxide-covered aluminum is 9.5, and of oxide-covered tantalum is approximately -0.7. These values for the oxide films are within one to three pH units of the reported isoelectric points for the corresponding bulk oxide powders. The oxide-covered metal surfaces were cleaned by argon plasma treatment prior to measurement of contact angles, in that XPS measurements showed this treatment to be effective in reducing the thickness of the carbon contamination layer. In addition, interfacial tensions were measured at the hexadecane/aqueous solution interface and were observed to have only a slight dependence on the pH of the aqueous phase. Copyright 1997 Academic Press. Copyright 1997Academic Press

Stress and suicide in police officers: paradigm of occupational stress.

All occupations are associated with stress, but certain occupations are significantly more stressful than others. Stress is not always harmful. It is the individual's reaction to stress that determines the outcome, ie, whether the individual will adapt or become maladaptive. Individuals who feel they can control events or are in control of their lives are better able to handle stress than individuals who believe they are the victims of fate or chance and who feel powerless and helpless. For those individuals who feel powerless or helpless, suicide may be a means of taking control over their helplessness. Police officers, who are subject to extraordinary stress, present a paradigm for the study and treatment of stress in other occupations.

Posttraumatic stress disorder in the police officer: paradigm of occupational stress.

The police officer is exposed to stress outside the range of usual human experience, which often leads to his demoralization and brutalization, and predisposes him to a posttraumatic stress disorder similar to that found in the Vietnam veteran. With posttraumatic stress disorder comes functional deterioration that can lead to significant psychologic and health problems, not only for the police officer, but also for his family. Posttraumatic stress disorder in the police officer has counterparts in other stressful occupations. Current treatment methods are outlined.

Murine interstitial nephritis. IV. Long-term cultured L3T4+ T cell lines transfer delayed expression of disease as I-A-restricted inducers of the effector T cell repertoire.

In the present study we observed that long-term cultures of tubular antigen-reactive L3T4+ T cells from immune SJL mice are able to adoptively transfer interstitial nephritis by 12 wk after i.v. injection. Lesions that develop under these conditions generally occur in the absence of anti-tubular basement membrane antibody formation. These cultured T cell lines are I-A restricted, require L3T4-associative interactions, and are tubular antigen specific, but do not share the phenotype, function, or H-2-restriction characteristics of Lyt-2+ nephritogenic effector T lymphocytes. Rather, our L3T4+ T cell lines, and phenotypically similar lymphocytes harvested from renal infiltrates, are inducers of this Lyt-2+ effector T cell repertoire. Such effector T cells, typically found in immune lymph nodes 4 to 7 days after immunization, can be induced in vitro within 5 days and will acutely transfer disease within another 5 days when placed under the kidney capsule. These findings collectively indicate that the time course for optimal effector cell differentiation and potential expression is relatively short. The immunologic inertia we previously observed between immunization or i.v. adoptive transfer and the development of cellular lesions, therefore, seems to reside in other systemic or interactional events beyond the timely formation of effector T cells.

Tubular antigen-derivatized cells induce a disease-protective, antigen-specific, and idiotype-specific suppressor T cell network restricted by I-J and Igh-V in mice with experimental interstitial nephritis.

The nephritogenic effector T cell response producing interstitial nephritis in mice can be largely inhibited by the adoptive transfer of suppressor T cells before or after the induction of disease. These suppressor T cells are harvested from donor mice primed with tubular antigen-derivatized syngeneic lymphocytes, and two subsets of suppressor cells can be characterized within this donor cell population. The first suppressor cell in this network is an L3T4+, I-J+, RE-Id+ cell (Ts-1). Ts-1 cells are antigen-binding suppressor cells that inhibit afferent phase immune responses and, in the presence of tubular antigen, specifically induce Lyt-2+, I-J+ cells (Ts-2) that are antiidiotypic (RE-Id-binding) suppressors. The Ts-2 cell is functionally restricted in its suppressive effect by I-J and Igh-V gene products, and acts on the effector limb of the cell-mediated anti-tubular basement membrane immune response. These studies provide an experimental basis for further efforts to use immunoregulatory modulation in the control of autoimmune renal disease.

Murine interstitial nephritis. III. The selection of phenotypic (Lyt and L3T4) and idiotypic (RE-Id) T cell preferences by genes in Igh-1 and H-2K characterizes the cell-mediated potential for disease expression: susceptible mice provide a unique effector T cell repertoire in response to tubular antigen.

The effector T cell repertoire in experimental interstitial nephritis was examined in a variety of susceptible and nonsusceptible mice. We observed that L3T4+ effector T cells in disease-susceptible mice disappear soon after immunization in preference to the emergence of Lyt-2+ effector cells. These latter cells respond with delayed-type hypersensitivity to tubular antigen in the context of H-2K. Such cells also express idiotypes (RE-Id) shared with kidney-bound alpha TBM-Ab that are regulated by an interactional effect of genes in Igh-1 and H-2K. These Lyt-2+ effector cells can be removed from renal infiltrates, and the transfer of similar cells under the renal capsule of naive mice results, within 5 days, in local interstitial nephritis. Nonsusceptible mice, however, not having these immune response genes, produce either L3T4+, Lyt-1+, RE-Id- effector T cells, which only respond to tubular antigen in the context of I-A, or Lyt-2+, RE-Id- T cells, which may lack very fine specificity. These findings suggest that susceptible mice carry a unique set of immune response genes that promote a T cell selection process that operates after induction, during the differentiation and development of disease-producing effector T cells.

Spontaneous interstitial nephritis in kdkd mice. I. An experimental model of autoimmune renal disease.

Mice of the kdkd strain predictably develop a spontaneous tubulointerstitial nephritis after 8 wk of life. In this report we have examined several aspects of the nephritogenic immune response that seemed potentially relevant to the expression of this progressively destructive renal lesion. Of particular interest is that by direct immunofluorescence we were unable to demonstrate the presence of antibodies to determinants in the tubulointerstitium. Serum and kidney eluates from nephritic mice, furthermore, did not stain any renal structures in normal kidney. We did observe, however, that disease could be transferred through kdkd----CBA/Ca bone marrow chimeras, and prevented, in the reverse direction, by CBA/Ca----kdkd chimeras. The development of the interstitial lesion was markedly inhibited by thymectomy with T cell depletion, but disease could not be adoptively transferred with cells or serum from nephritic mice. The interstitial lesions also did not appear in (kdkd X CBA/Ca)F1 hybrids, and the development of disease in kdkd mice could be inhibited by treatment with adoptively transferred T cells from CBA/Ca mice. With these new findings we now hypothesize that susceptibility to the expression of interstitial nephritis in kdkd mice involves the cellular limb of the immune system, and may be related, in part, to alterations in regulatory T cell function.

Murine interstitial nephritis. II. The adoptive transfer of disease with immune T lymphocytes produces a phenotypically complex interstitial lesion.

The present studies demonstrate that immune Thy-1.2+, Lyt-1.2+ T lymphocytes harvested from SJL mice with anti-tubular basement membrane disease can adoptively transfer interstitial nephritis into naive recipients. The lesions produced after cell transfer do not occur immediately but rather take 4 to 6 wk to fully develop. Interstitial lesions can also be transferred to a lesser degree and over a longer period of time with immune serum containing anti-tubular basement membrane antibodies. The fully formed lesions that developed after the transfer of immune cells or serum were phenotypically characterized by cell-surface antibodies using immunofluorescence. T lymphocytes, natural killer cells, macrophages, and Ig+ cells were all well represented in both lesions. Natural killer cells, however, were slightly more prevalent in the lesions of mice receiving immune serum. These experiments demonstrate a potential role for both immune T lymphocytes and anti-tubular basement membrane antibodies in the development of interstitial nephritis in mice. Unlike guinea pigs and rats, it is only in mice that interstitial lesions can be adoptively transferred with immune T lymphocytes, and as such, this model should prove very useful in the additional dissection of cellular interactions and immunoregulatory events that formulate the final effector mechanisms of disease expression.

Antiidiotypic immunity in interstitial nephritis. II. Rats developing anti-tubular basement membrane disease fail to make an antiidiotypic regulatory response: the modulatory role of an RT7.1+, OX8- suppressor T cell mechanism.

Antiidiotypic immunity can successfully inhibit the development of antitubular basement membrane (alpha TBM) disease that produces interstitial nephritis. Rats normally immunized to produce disease, however, do not develop this regulatory and protective antiidiotypic effect. The failure to see such a regulatory response is functionally related to the influence of a nonspecific, RT7.1+, OX8-suppressor T cell that appears shortly after immunization. While this suppressor cell system can partially reduce the intensity of disease, it also limits the host's ability to specifically regulate the alpha TBM immune response and, hypothetically, leaves the disease process in an operationally active mode.

Mapping of the genes for tubular basement membrane antigen and a submaxillary gland protease in the rat.

The gene for tubular basement membrane (Tbm) antigen in the rat has been mapped relative to other markers in the first linkage group, and a polymorphic locus for a submaxillary gland protease, Tamase-1, has been identified. The hair-loss mutation fuzzy has also been mapped and occupies a position which is similar to that of the frizzy gene in the mouse. There are now at least five, and possibly six, genetic loci distributed over more than 30 centimorgans in the first linkage group of the rat which map in positions of approximate homology on the seventh chromosome of the mouse.

Polymorphism of genes involved in anti-tubular basement membrane disease in rats.

Inbred strains of rats differ widely in their susceptibility to interstitial nephritis induced by rabbit renal tubular basement membrane (TBM) preparations. We now report that susceptibility is determined in part by an RT1-linked gene for effector cell responsiveness producing interstitial lesions. Furthermore, we also obtained evidence that the gene determining expression of the target TBM antigen is linked to the gene for albinism on the first linkage group. When non-susceptible rats lacking the TBM antigen but having the gene for cellular responsiveness were mated with non-susceptible rats which had the TBM antigen but lacked the gene for cellular responsiveness, the F1 hybrids were susceptible to the induction of interstitial nephritis. Although strains varied widely in the amount of anti-TBM antibody (alpha TBM-Ab) they produced, this variation does not appear to be controlled by RT1-linked genes, nor does the isotype or amount of antibody appear to be related to the susceptibility to infiltrating cellular lesions.

The effect of ethinyl estradiol 20 mcg and levonorgestrel 250 mcg on the pituitary-ovarian function during normal tablet-taking and when tablets are missed.

A new combined pill containing 20 micrograms of ethinyl estradiol and 250 micrograms of levonorgestrel has been developed. The safety margin of this type of low-dose preparation needed to be assessed and this was done by evaluating daily levels of LH, FSH, estradiol, progesterone, 1-NG and EE2 as well as cervical mucus characteristics in six patients when one and then two consecutive pills were deliberately omitted mid-way through the cycle. Results demonstrated that there was no evidence of breakthrough ovulation, although there was some continued ovarian steroidogenesis, a feature consistent with previous studies using combined preparations. Existing instructions to patients regarding missed pills should continue in order to ensure maximal contraceptive safety.