Human neutrophils do not degrade major basement membrane components during chemotactic migration

At sites of inflammation, circulating neutrophils (PMNs) migrate through microvessel walls into the subendothelial interstitium. While endothelial passage is mediated by adhesion proteins, including those of the integrin, selectin and immunoglobulin superfamily classes, the mechanisms used to cross the subendothelial basement membrane (BM) are unclear. Studies examining tumour cell invasion and lymphocyte extravasation suggest several possible mechanisms, including proteolysis. Different cells, however, may use different mechanisms to effect passage. To examine neutrophil-basement membrane interactions in more detail, human PMNs were embedded within reconstituted BM (Matrigel) and used in migration assays. The integrity of the gel following migration was assessed by assaying for the release of incorporated radiolabelled products and by-immunoblotting for specific matrix molecule epitopes. PMNs migrated through Matrigel in response to the chemotactic peptide FMLP. Degradation products of laminin, heparan sulphate proteoglycan or of gelatin, however, were not detected. In contrast, phorbol ester, which triggers activation without migration, released approximately 40% of incorporated HSPG, 30% of gelatin and 20% of laminin as intact molecules or degraded fragments. Electron microscopy of migrating cells demonstrated pseudopodia associated with channels within the Matrigel. Although the serine proteinase inhibitor DFP, plasma and a specific anti-neutrophil elastase IgG blocked degradation, these agents failed to inhibit migration. Migration was inhibited, however, when the Matrigel concentration was increased to 10 mg/ml. Thus, although PMNs will degrade matrix components they do not do so during migration, and proteolytic remodelling of the BM is not a pre-requisite for neutrophil passage.     

A recombinant single chain antibody neutralizes coronavirus infectivity but only slightly delays lethal infection of mice

The variable region genes of a murine anti-coronavirus monoclonal antibody (mAb) were joined by assembly polymerase chain reaction and expressed in Escherichia coli in a single chain variable fragment (scFv) configuration. After induction of expression, the expected 32-kDa protein was identified by Western immunoblotting with specific rabbit anti-idiotype antibodies. The scFv fragments were purified from soluble cytoplasmic preparations by affinity chromatography on nickel agarose, which was possible with an N-terminal but not with a C-terminal histidine tag. Purified scFv fragments retained the antigen-binding properties of the parental antibody, could inhibit its binding to viral antigens with apparently higher efficiency than monovalent antigen-binding (Fab) fragments, but neutralized viral infectivity with lower efficiency (about sevenfold at a molar level). To evaluate the usefulness of these smaller and less immunogenic molecules in the treatment of viral diseases, mice were treated with purified recombinant scFv fragments and challenged with a lethal viral dose. A small delay in mortality was observed for the scFv-treated animals. Therefore, even though the scFv could neutralize viral infectivity in vitro, the same quantity of fragments that partially protected mice in the form of Fab only slightly delayed virus-induced lethality when injected as scFv fragments, probably because of a much faster in vivo clearance: the biologic half-life was estimated to be about 6 min. Since a scFv derived from a highly neutralizing and protective mAb is only marginally effective in the passive protection of mice from lethal viral infection, the use of such reagents for viral immunotherapy will require strategies to overcome stability limitations.     

Large debris flows: A macro-viscous phenomenon

Summary Field observations from a variety of sources suggest that destructive debris flows occur when the density of the fluid-solid mixture exceeds about 1.5 T/m³, and that their destructive ability is due to their pulsing nature and to their ability to carry large boulders.If debris flows are treated as a macroviscous flow of large stones in a slurry of fine solids in water, several of their obvious characteristics (boulder transport, deep bed erosion, intermittent jamming) can be explained. Further, the amplification and translation in a main channel of random surges due to jamming in tributaries explains the regular, large pulses in Chinese debris flows as a roll-wave phenomenon.With 5 Figures     

Dermal exposure of amateur or non-occupational users to wood-preservative fluids applied by brushing outdoors

512 specimens of the bronchoalveolar fluid of 171 patients with acute and chronic inflammatory processes in the lung were studied. It was shown that significant qualitative and quantitative changes in cellular composition of the bronchoalveolar fluid occurred under the influence of a helium-neon laser: an increase in the percentage of macrophages and a decrease in the percentage of neutrophils. With the help of autoradiographic studies the induction of metabolic and proliferative activity (according to level of RNA- and DNA-synthesis) of alveolar macrophages after laser treatment was revealed. Based on morphologic changes of the respiratory compartment of the lung, conclusions were drawn about the stimulation of the functional activity of alveolar macrophages as a basis of the clinical effect of laser therapy on acute and chronic inflammatory processes.     

A UK-wide trial of the Banff classification of renal transplant pathology in routine diagnostic practice

BACKGROUND: The Banff classification of renal transplant pathology has gained wide support since its introduction in 1993. There have been several studies which have tested its usefulness in the context of research-oriented centres. We sought to evaluate its use in a wider context. METHODS: We recruited pathologists from all but one of the renal transplant centres in the UK. Sections were circulated from 21 selected, 'difficult' cases, in all of which the clinical question was confirmation or exclusion of acute rejection, and in all of which a definite diagnosis had been obvious from the subsequent clinical course. Participants were asked first to diagnose or exclude acute rejection by their usual approach, then to apply the Banff classification. No clinical information was given beyond the time since engraftment, in order to confine the evaluation to the morphological features present in the sections. At the end of the study the subjective impressions of the participants were sought using a structured questionnaire. RESULTS: Using the Banff classification produced no detectable difference in the number of 'correct' diagnoses when compared with a conventional approach, irrespective of whether the 'correct' diagnosis is based on retrospective clinical information or on the consensus opinion of the pathologists involved, and irrespective of where in the Banff schema one applies a 'cut-off' for the diagnosis of acute rejection. However, the reproducibility of the diagnoses was improved. The results suggest that in the Banff classification the best 'cut-off' for the diagnosis of acute rejection is between Banff category 3 and category 4, although in this difficult area we found a large improvement in diagnostic accuracy if input of clinical information occurs. CONCLUSIONS: The improved reproducibility justifies the use of the Banff classification to harmonise approaches between centres, especially in research projects. While there are good reasons also to adopt it in routine diagnostic practice, further refinement is necessary before an improvement in the accuracy of diagnosis can be demonstrated.     

Use of model plant hosts to identify Pseudomonas aeruginosa virulence factors

We used plants as an in vivo pathogenesis model for the identification of virulence factors of the human opportunistic pathogen Pseudomonas aeruginosa. Nine of nine TnphoA mutant derivatives of P. aeruginosa strain UCBPP-PA14 that were identified in a plant leaf assay for less pathogenic mutants also exhibited significantly reduced pathogenicity in a burned mouse pathogenicity model, suggesting that P. aeruginosa utilizes common strategies to infect both hosts. Seven of these nine mutants contain TnphoA insertions in previously unknown genes. These results demonstrate that an alternative nonvertebrate host of a human bacterial pathogen can be used in an in vivo high throughput screen to identify novel bacterial virulence factors involved in mammalian pathogenesis.     

A comparison of the effects of capsaicin with inhibitory nerve stimulation in the rat anococcygeus muscle in vitro

A cross-sectional study of serum selenium levels in patients (n = 59) with different types of cancer from southeastern Spain was carried out using hydride generation atomic absorption spectrometry. The subjects were divided into four groups according to the cancer location (respiratory, digestive, haematological and gynaecological groups). Serum selenium levels in all patients (54.41 +/- 24.80 mg/l) were significantly lower (P < 0.001) than those determined in control groups [healthy subjects from the same area (n = 130) and institutionalized elderly people (n = 93)]. Mean serum selenium concentrations were not significantly different among the four groups considered (P > 0.05). Linear regression analyses performed on serum selenium levels and biochemical markers (total cholesterol, triglycerides, transaminases, uric acid and urea) did not establish any statistically significant correlation (P > 0.05). No significant relationships between serum selenium concentrations and sex or age of patients was observed (P > 0.05). Given the marked overlap between the two ranges of the populations (the means are within approx. 1/2 S.D.) the predictive values of serum selenium are low. Thus, there is indeed a statistical significance between the means, but selenium cannot be used to determine whether or not a patient has cancer disease.     

Long-term epilation using the EpiLight broad band, intense pulsed light hair removal system

BACKGROUND: The long-term epilation of hair is the goal of several lasers and intense pulsed light systems. OBJECTIVE: The purpose of the study is to use the EpiLight Hair Removal System to assess long-term epilation and to assess its safety profile following a single treatment session. METHODS: Patients received a single treatment with the Epilight Hair Removal System after entering the patient's skin type, skin color, hair color, and hair density into the system's computer software. Treatment parameters include various wavelengths of light, pulse duration, pulse delay, and energy fluence. Thirty-seven subjects received a single treatment using one of four cut-off filters consisting of two to five pulses with energies of 34-55 J/cm2. RESULTS: The results of a single treatment show hair clearances occurring immediately and over a 12-week study period. Approximately 60% hair removal was noted at 12 weeks. CONCLUSIONS: The EpiLight Hair Removal System is an effective and safe method for long-term epilation of unwanted hair.