Regulation of nuclear factor-kappa B and its inhibitor I kappa B-alpha/MAD-3 in monocytes by Mycobacterium tuberculosis and during human tuberculosis

Blood monocytes from patients with active tuberculosis are activated in vivo, as evidenced by an increase in the stimulated release of proinflammatory cytokines, such as TNF-alpha, and the spontaneous expression of IL-2R. Further, monocytes from patients demonstrate an augmented susceptibility to a productive infection with HIV-1 in vitro. Mycobacterium tuberculosis and its components are strong signals to activate monocytes to production of cytokines. In this study we examined the basis of activation of monocytes during active tuberculosis and by M. tuberculosis. We found a constitutive degradation of I kappa B-alpha, the major cytoplasmic inhibitor of nuclear factor kappa B (NF-kappa B), in freshly isolated PBMC and monocytes from patients with tuberculosis. In contrast, I kappa B-alpha levels in PBMC and monocytes from healthy subjects or from patients with nontuberculous pulmonary conditions were intact. Further, by electrophoretic mobility shift assay, NF-kappa B was activated in monocytes from tuberculous patients. The expression of I kappa B-alpha gene, which is responsive to activation by NF-kappa B, was up-regulated in PBMC and monocytes from patients, but not in mononuclear cells from healthy subjects or those with nontuberculous lung diseases. By contrast, the expression of other adherence-associated early genes, such as IL-8 and IL-1 beta, was not up-regulated in PBMC of tuberculous patients. Further, M. tuberculosis and its tuberculin, purified protein derivative, induced the degradation of I kappa B-alpha and the expression of I kappa B-alpha mRNA, and purified protein derivative induced the activation of NF-kappa B in monocytes.     

Plasma alpha-tocopherol, beta-carotene, and lipid levels in semi-free-ranging Przewalski horses (Equus przewalskii)

To describe the features of railway-related deaths in Cape Town, South Africa, we reviewed demographic, autopsy, and accident report data on all such deaths between 1 April 1992 and 30 September 1994. Of the 379 railway-related deaths, 27 were among pedestrians or commuters who were hit by a train while crossing the track, 38 were among commuters who fell from moving trains, 32 were suicides, 43 were the result of criminal violence on trains or at railway stations, and 38 were due to other causes. Most railway fatalities were among men between the ages of 25 and 44 years. About half of all railway fatalities occurred at peak commuting times, with high levels of violence (often robbery related) recorded during the evening peak. A blood alcohol concentration > 0.1 g/100 ml was found in 35% of the people who died from crossing the track or falling from moving trains. Fatal railway injury is characterized by extensive disruption of more than one body region. The high levels of fatal railway injury make a strong case for a range of injury control interventions, including ticket control, surveillance, law enforcement, and safety engineering.     

Pre- and postoperative radiotherapy to prevent heterotopic ossification of the hip joint

BACKGROUND: In-vivo experimental data indicate that both pre- and postoperative radiotherapy can prevent heterotopic ossification after hip surgery. This comparison was clinically tested in a randomized study. PATIENTS AND METHODS: From June 1992 to September 1993, 84 patients with high risk for the development of heterotopic ossification were randomized. The treatment concept consisted either of preoperative radiotherapy within four hours prior to surgery (arm A) or postoperative radiotherapy within 72 hours following hip surgery (arm B). Preoperative radiotherapy was given in one fraction of 7 Gy, while the postoperative radiotherapy was delivered in five fractions of each 3.5 Gy (total 17.5 Gy). All patient variables (age, sex, prior surgery) and predisposing risk factors were comparable in both treatment arms. For the radiological assessment of heterotopic ossification according to (Brooker-Score) X-rays of the pelvis or hip were evaluated which had been taken immediately pre- and postoperatively as well as at least six months following surgery and prophylactic irradiation. The functional hip status was evaluated pre- and postoperatively using the Harris-Score. Cases in which the Brooker- and/or Harris-Score worsened during the postoperative follow-up as compared to the pre- and immediate postoperative situations were considered as treatment failures. RESULTS: Of 44 patients with at least six months follow-up 41 (93%) experienced a successful prophylaxis. Two failures were observed in the preoperative and one in the postoperative group. The prophylactic efficacy was not influenced if the pre- or postoperative interval was longer than prescribed. All intra- and postoperative complications were comparable for both treatment groups. The mean interval to partial strain (50% body weight) of the operated hip was longer in the preoperative group (mean 19 +/- 27 days) as compared to the postoperative group (mean 8 +/- 13 days). With respect to full strain (100% body weight), the results were equal in both groups. The functional hip status decreased in two patients. Again the mean overall improvement in the postoperative group was larger (mean 42.7 +/- 17.1 points) as compared to the preoperative group (mean 34.3 +/- 13.7 points). CONCLUSIONS: Preoperative and postoperative radiotherapy have equal prophylactic efficacy to prevent heterotopic ossification following hip surgery. The main advantage of preoperative radiotherapy are the simple management of the patient, the reduction of possible complications associated with transport and positioning of the patient in the postoperative period as well as excellent acceptance of this treatment concept by patients, nurses and staff.     

Use of magnetic resonance imaging scanning in adrenocortical carcinoma with vena caval involvement

We report on 2 cases of an adrenocortical carcinoma with vena caval involvement. Preoperative evaluation included a magnetic resonance imaging (MRI) scan confirming the presence of vena caval involvement. Extremely precise detail of the vena caval tumor thrombus was very helpful in preparing for the surgical extirpation. MRI detail far outweighed what was seen on the computed tomography scan and venacavogram. The MRI scan correlated exactly with what was found surgically. Although MRI scanning has been used to evaluate renal tumors with vena caval extension, few cases have been reported with similar adrenal tumors.     

Cross-linking of the CD40 ligand on human CD4+ T lymphocytes generates a costimulatory signal that up-regulates IL-4 synthesis

Although there is good evidence that the induction of IL-4 synthesis in CD4+ T lymphocytes is favored by Ag presentation by B cells and not macrophages, the precise molecular signals provided by B cells to T cells that enhance IL-4 synthesis are not clear. To examine this issue, we established an APC-independent system to activate highly purified T cells and induce cytokine synthesis, using immobilized mAbs against several T cell surface molecules, including CD3, CD28, and the CD40 ligand (CD40L). The counter-receptors for all three of these molecules are expressed on B cells, and include CD40, which is expressed primarily on B cells, but also on dendritic cells and thymic epithelium. We found that IL-4 synthesis was greatly enhanced by triggering of CD40L on the T cell surface in conjunction with ligation of CD3/TCR and CD28, whereas ligation of CD3/TCR and CD28 in the absence of CD40L triggering resulted in little or no IL-4 synthesis. CD40L costimulation greatly enhanced IL-4 synthesis both in T cells from normal nonallergic adult subjects as well as in naive T cells from cord blood. Furthermore, we demonstrated that IL-4 synthesis was optimally enhanced when the strength of the CD3/TCR signal was limiting, while IL-4 synthesis was inhibited when CD3/TCR stimulation was maximal. These studies confirm that IL-4 synthesis can be induced in normal T lymphocytes in the absence of exogenous IL-4, and demonstrate that CD40L costimulation is of fundamental importance in regulation of IL-4 production. In addition, these findings provide a mechanism by which B cells preferentially enhance IL-4 synthesis in T cells at low Ag concentrations.     

Selective induction of protection against influenza virus infection in mice by a lipid-peptide conjugate delivered in liposomes

We have previously reported (Muller et al. Vaccine 1990, 8, 308) that two cyclic peptide analogues called D loop and K loop, corresponding to residues 139-147 in site A of the haemagglutinin (HA) of influenza A virus (strain X31), were both able to provide protective immunity to infected OF1 mice when administered in the form of peptide-ovalbumin conjugates. The predicted conformation of the D loop is nearly identical to that of the native loop known from the X-ray structure of HA, while the predicted conformation of the K loop differs significantly from the native one. In this study, the two peptides were conjugated to small unilamellar liposomes, thus creating a chemically defined immunogen, and OF1 mice were immunized with these liposomes containing monophosphoryl lipid A as adjuvant. Compared with protein carrier systems, the liposomal preparations are completely synthetic and avoid the use of Freund's adjuvant. By using liposomes associated with the D loop, we were able to achieve 70% protection of the mice against intranasal challenge with the influenza virus while no protection was obtained with the liposome-associated K loop. The difference in effect between the two liposome and ovalbumin carrier systems may result from the induction of different structures in the peptides when coupled to lipid anchors than when coupled to proteins.     

Mechanisms of biomaterial-induced superoxide release by neutrophils

Biomaterial-centered infection is an important cause of the failure of prosthetic implants and organs. Because neutrophils mediate host defense against infection, the effect of biomaterials on neutrophil superoxide release and the mechanism of that effect were investigated using three materials commonly employed in surgical practice. The graft materials were expanded polytetrafluorethylene (PTFE), polyurethane and woven dacron. Polystyrene, a commonly used laboratory support vessel, was also studied. Both polystyrene and polyurethane were activating, but serum inhibitable, whereas PTFE was nonactivating, and woven dacron was not activating unless serum was present. The signaling mechanisms used by these materials demonstrated time and material dependency. Pertussis toxin inhibition of G protein-dependent activation had little or no effect on biomaterial induced activation, whereas FMLP-induced activation of the same biomaterial-associated cells was inhibited. Protein kinase C inhibition with staurosporine greatly inhibited polystyrene-induced activation, but had only a partial effect with polyurethane and even less effect with the activation associated with serum-treated woven dacron. These studies demonstrated that biomaterial contact-induced neutrophil activation differed from that described for cells in suspension, and showed that activation mechanisms on one material cannot be extrapolated to mechanisms on other materials.     

Detection of extracellular proteases from microorganisms on agar plates

We present herein an improved assay for detecting the presence of extracellular proteases from microorganisms on agar plates. Using different substrates (gelatin, BSA, hemoglobin) incorporated into the agar and varying the culture medium composition, we were able to detect proteolytic activities from Pseudomonas aeruginosa, Micrococcus luteus and Serratia marcescens as well as the influence that these components displayed in the expression of these enzymes. For all microorganisms tested we found that in agar-BHI or yeast extract medium containing gelatin the sensitivity of proteinase detection was considerably greater than in BSA-agar or hemoglobin-agar. However, when BSA or hemoglobin were added to the culture medium, there was an increase in growth along with a marked reduction in the amount of proteinase production. In the case of M. luteus the incorporation of glycerol in BHI or yeast extract gelatin-agar induced protease liberation. Our results indicate that the technique described here is of value for detecting extracellular proteases directly in the culture medium, by means of a qualitative assay, simple, inexpensive, straight forward method to assess the presence of the proteolytic activity of a given microorganism colony with great freedom in substrate selection.