A Convolutional-Transformer Model for FFR and iFR Assessment From Coronary Angiography.

The quantification of stenosis severity from X-ray catheter angiography is a challenging task. Indeed, this requires to fully understand the lesion's geometry by analyzing dynamics of the contrast material, only relying on visual observation by clinicians. To support decision making for cardiac intervention, we propose a hybrid CNN-Transformer model for the assessment of angiography-based non-invasive fractional flow-reserve (FFR) and instantaneous wave-free ratio (iFR) of intermediate coronary stenosis. Our approach predicts whether a coronary artery stenosis is hemodynamically significant and provides direct FFR and iFR estimates. This is achieved through a combination of regression and classification branches that forces the model to focus on the cut-off region of FFR (around 0.8 FFR value), which is highly critical for decision-making. We also propose a spatio-temporal factorization mechanisms that redesigns the transformer's self-attention mechanism to capture both local spatial and temporal interactions between vessel geometry, blood flow dynamics, and lesion morphology. The proposed method achieves state-of-the-art performance on a dataset of 778 exams from 389 patients. Unlike existing methods, our approach employs a single angiography view and does not require knowledge of the key frame; supervision at training time is provided by a classification loss (based on a threshold of the FFR/iFR values) and a regression loss for direct estimation. Finally, the analysis of model interpretability and calibration shows that, in spite of the complexity of angiographic imaging data, our method can robustly identify the location of the stenosis and correlate prediction uncertainty to the provided output scores.

Expression and role of IL-15 in post-burn hypertrophic scars.

Hypertrophic scarring is a skin disorder that occurs after wounding and thermal injury. There is accumulating evidence that immunologic processes such as infiltration of activated T lymphocytes and altered cytokine production may play a role in the formation of hypertrophic scars. Interleukin-15, a cytokine identified as a T cell growth factor, also acts as a chemoattractant for T cells and has pro-inflammatory properties. We investigated the expression and the role of this cytokine in hypertrophic scarring. IL-15 expression was compared in skin biopsies of hypertrophic scars (HS) both in active (AHS) and in remission (RHS) phases, in normotrophic scars (NTS) and in normal skin using reverse transcriptase-polymerase chain reaction and immunohistochemistry. IL-15 expression in HS was significantly higher than in NTS or normal skin. Furthermore, AHS expressed higher levels of IL-15 than RHS. Immunohistologic analysis of AHS samples showed strong IL-15 immunoreactivity in keratinocytes and Langerhans cells in the epidermis and in macrophages, fibroblasts, and dermal dendritic cells in the dermis. High levels of IL-15 expression in AHS correlated with abundant infiltration of activated CD3+ cells. Ex vivo experiments indicate that IL-15 can sustain the proliferative response of T cells derived from AHS but not from RHS and NTS. In addition, IL-15 prevents both cytokine deprivation and activation-induced apoptosis of T cells derived from AHS. Taken together, these results suggest that IL-15 can be involved in the recruitment, proliferation, and apoptosis inhibition of T cells in AHS. The findings that the evolution from an AHS to a RHS is associated with a decrease in IL15 expression, and with a loss of IL-15 responsiveness in ex vivo-cultured T cells, indicate that this cytokine plays an important role in the biology of pathologic scar formation.

Human monocytes constitutively express membrane-bound, biologically active, and interferon-gamma-upregulated interleukin-15.

Interleukin-15 (IL-15) is a potent regulator of T-, B-, and natural killer cell proliferation and displays unusually tight controls of secretion. Even though IL-15 mRNA is constitutively expressed in monocytes/macrophages and is upregulated by a variety of stimuli, evidence for IL-15 cytokine secretion is only found exceptionally, eg, conditions of pathological, chronic inflammation. This raises the possibility that monocytes express membrane-bound IL-15 rather than secrete it. The current study explores this hypothesis. We demonstrate here that biologically active IL-15 is indeed detectable in a constitutively expressed, membrane-bound form on normal human monocytes, as well as on monocytic cell lines (MONO-MAC-6, THP-1, and U937), but not on human T or B cells (MT4, M9, C5966, JURKAT, DAUDI, RAJI, and Epstein-Barr virus-immortalized B-cell clones). Furthermore, cell surface-bound IL-15 is upregulated upon interferon-gamma stimulation. Interestingly, monocyte/macrophage inhibitory cytokines such as IL-4 and IL-13 fail to downregulate both constitutive and induced cell-surface expression of IL-15. Membrane-bound IL-15 does not elute with acetate buffer or trypsin treatment, suggesting that it is an integral membrane protein and that it is not associated with the IL-15 receptor complex. Finally, membrane-bound IL-15 stimulates T lymphocytes to proliferate in vitro, indicating that it is biologically active. These findings enlist IL-15 in the fairly small family of cytokines for which the presence of a biologically active membrane-bound form has been demonstrated (eg, IL-1, tumor necrosis factor-alpha, and IL-10) and invites the speculation that most of the biological effects of IL-15 under physiological conditions are exerted by the cell surface-bound form.

Interleukin-15 activates proinflammatory and antimicrobial functions in polymorphonuclear cells.

Interleukin-15 (IL-15) is a recently discovered cytokine produced by a wide range of different cell types including fibroblasts, keratinocytes, endothelial cells, and macrophages in response to lipopolysaccharide or microbial infection. This suggests that IL-15 may play a crucial role in the activation of phagocytic cells against pathogens. We studied polymorphonuclear leukocyte (PMN) activation by IL-15, evaluated as enhancement of PMN anti-Candida activity as well as IL-8 production, following stimulation with the cytokine. The PMN response to IL-15 depends on binding to the IL-15 receptor. Our experiments show that binding of a biotinylated human IL-15-immunoglobulin G2b IgG2b fusion protein was competed by the addition of human recombinant IL-15 (rIL-15) or of human rIL-2, suggesting that IL-15 binding to PMN might involve the IL-2Rbeta and IL-2Rgamma chains, which have been shown to be constitutively expressed by PMN. In addition, we show by reverse transcription-PCR and by flow cytometry with a specific anti-IL-15Ralpha chain monoclonal antibody that PMN express the IL-15Ralpha chain at the mRNA and protein levels. Incubation with IL-15 activated PMN to secrete the chemotactic factor IL-8, and the amount secreted was increased by costimulation with heat-inactivated Candida albicans. In addition, IL-15 primed the metabolic burst of PMN in response to formyl-methionyl-leucyl-phenylalanine but was not sufficient to trigger the respiratory burst or to increase the production of superoxide in PMN exposed to C. albicans. IL-15 also increased the ability of PMN to phagocytose heat-killed C. albicans organisms in a dose-dependent manner, without opsonization by antibodies or complement-derived products. In the same concentration range, IL-15 was as effective as gamma interferon (IFN-gamma) and IL-2 in increasing the C. albicans growth-inhibitory activity of PMN. Taken together, these results suggest that IL-15 is a potent stimulant of both proinflammatory and antifungal activities of PMN, activating several antimicrobial functions of PMN involved in the cellular response against C. albicans.

Detection of Pneumocystis carinii by DNA amplification in human immunodeficiency virus-positive patients.

The opportunistic pathogen Pneumocystis carinii (PC) is a frequent cause of a life-threatening pneumonia in human immunodeficiency virus (HIV)-infected individuals and in other immunocompromised hosts. Specimens obtained from 128 bronchoalveolar lavage (BAL) fluid samples from 123 HIV-positive patients with pulmonary disease and undergoing a diagnostic bronchoscopy were evaluated to detect this organism. We have developed a rapid DNA extraction procedure for nested polymerase chain reaction (PCR) using two sets of primers (pAZ102-E, pAZ102-H and P1 = 5'-CTAGGATATAGCTGGTTTTC-3' and P2 = 5'-TCGACTATCTAGCTTATCGC-3'). The results were compared using cytological techniques (direct wet mount, Giemsa, toluidine blue O) and related to the clinical follow-up of patients. The nested PCR had a 91% sensitivity and a 93% specificity. The effect of chemoprophylaxis and the evaluation of the follow-up of patients are discussed. Nested PCR may represent an important additional tool, along with current cytological methods, for the detection of P. carinii; however, at present it cannot replace routine microbiological methods more simple and less expensive.

Interleukin-15 (IL-15) induces IL-8 and monocyte chemotactic protein 1 production in human monocytes.

Interleukin-15 (IL-15) is a recently characterized cytokine that shares many biological activities with IL-2 and interacts with the beta and gamma components of the IL-2 receptor. Unlike IL-2, which is secreted only by T cells, IL-15 is expressed preferentially by nonlymphoid tissues, epithelial, and fibroblast cell lines and by activated monocytes/macrophages. High concentrations of IL-15 have been shown in inflamed joints of rheumatoid arthritis patients, suggesting a role for IL-15 in inflammatory diseases where there is recruitment of leukocytes. Although monocytes have been shown to bind IL-15, its effects on these cells are not defined. In this report we show that supernatants of monocytes treated with IL-15-contained chemotactic activity for neutrophils and monocytes which was neutralized by anti-IL-8 or by anti-monocyte chemotactic protein 1 (MCP-1) antibodies, respectively. Secretion of IL-8 and MCP-1 proteins is detectable by enzyme-linked immunosorbent assay as early as 6 hours after stimulation with IL-15. Production of the two chemokines is correlated with induction by IL-15 of mRNA expression in monocytes. In addition, IL-8 and MCP-1 induction by IL-15 is differently regulated by interferon-gamma (IFN-gamma) and IL-4. IFN-gamma inhibited IL-15-induced IL-8 secretion, but synergized with IL-15 in MCP-1 induction; whereas IL-4 inhibited both IL-8 and MCP-1 induction by IL-15. These results show that IL-15 can stimulate monocytes to produce chemokines that cause inflammatory cell accumulation. Thus, IL-15 locally produced at sites of inflammation may play a pivotal role in the regulation of the leukocyte infiltrate.

Cytolytic and tumor inhibitory antibodies against UK114 protein in the sera of cancer patients.

UK114 is a 14 kDa protein identified in the perchloric acid soluble extract of goat liver. Anti-UK114 antibodies identify this protein as expressed by the membrane of human cancer cells. In the present study, anti-UK114 antibodies were detected in the sera of cancer patients by ELISA and by immunofluorescence tests using human cancer cell lines as a target. UK114 protein is antigenic in cancer patients. Human anti-UK114 antibodies have cytolytic effects in vitro and their presence correlates with inhibition of growth of human carcinoma cells xenografted in nu/nu mice. This finding may open new prospects for immunotherapy.

Evaluation of the immune response in visceral leishmaniasis.

Detection of parasites in culture or by microscopy is still necessary to make diagnosis of visceral leishmaniasis (VL). Serological methods still need assessment, as they are quick but not very sensitive, especially in immunosuppressed subjects. This paper compares the results obtained with three serological methods (indirect immunofluorescence test (IFAT), direct agglutination test (DAT), and enzyme-linked immunosorbent assay (ELISA) and the specific cell-mediated immune response, evaluated as proliferation and IFN-gamma production by peripheral blood lymphocytes (PBL) following stimulation with heat-killed L. infantum promastigotes. PBL and sera were obtained from 10 healthy donors, 3 VL patients in acute phase, and 3 patients recovering after two glucantim treatment courses. No false positive results were observed with the serological methods. IFAT can be considered the most sensitive and best suited for follow-up, as it allowed a good discrimination between the acute and remission phase. DAT did not discriminate between healthy donors and remission-phase patients, whereas ELISA is unsuited for follow-up, as it did not show any significant difference between remission- and acute-phase patients. Assessment of the cellular response is not recommended for making a diagnosis, because false positive results are frequent. However, a strong cellular response in a patient stands for a successful treatment. IFN-gamma titration is preferable to the proliferation test, because it gives earlier results and does not require the use of radioactive isotopes.

Pseudomonas aeruginosa clinical isolates: serotypes, resistance phenotypes and plasmid profiles.

78 Pseudomonas aeruginosa strains were isolated from the respiratory tract of 56 patients, 15 of which were affected by cystic fibrosis (CF). The epidemiological typing scheme was based on serotyping, antibiotic resistance pattern and plasmid DNA profile. All strains (except 2 mucoid strains) were typed using a rapid slide O-agglutination technique. Most common serotypes in both group were 0:1, 0:10 and 0:6. Moreover we observed a correlation among 0:12 serotype and CF patients. Plasmid DNA analysis showed that 45.2% (on average) of strains isolated from patients with and w/o CF harboured 1-3 plasmids ranging in size from 1 to 15 Md. Plasmid prevalence was higher in strains isolated from CF patients in specimens collected after antibiotic therapy. A correlation was found between 1 and 1.9 Md plasmids and resistance to aminoglycosides. Our results indicate that the analysis of antibiotic resistance phenotypes combined with plasmid analysis may be useful, in association to serotyping, to characterize the circulation of P. aeruginosa strains and the spread of resistance in these bacteria.

Aspecific adherence and cytotoxicity of Escherichia coli strains.

Two groups of Escherichia coli were assayed to evaluate hydrophobic characters and the secretion of enzymes and cytotoxic factors. Group 1 included strains isolated from the urine of patients with lower urinary tract infection (UTI) and group 2 included strains from the same sample of asymptomatic subjects. The bacterial hydrophobicity was similar in the two groups and related to their adhesion to plastic surfaces, while both cytotoxic factors (demonstrated using a microscopic and a spectrophotometric technique) and hydrolysing enymes were secreted more by the first group of E. coli. The superior production of these factors may be important in the pathogenesis and in the development of symptomatic UTI infections.

Protective role of the pefloxacin-IFN-gamma association in Leishmania major-infected mice.

Four groups of female Balb/c mice were inoculated in the left hind footpad with 30 microliters of RPMI 1640 medium containing 10(7) Leishmania major amastigotes/ml. One group was injected sc with 200 microliters of RPMI 1640 containing 180 micrograms of pefloxacin for 20 days, a second group with the same amount of medium containing 100 units of recombinant murine interferon gamma (rmIFN-gamma). The third group was treated with the association, while the fourth group received plain medium in an identical regimen. Pefloxacin or IFN-gamma significantly decreased the size of primary lesions, while their association was significantly more efficient in this respect, in reducing the incidence of metastatic lesions, and in clearing parasites from the spleen. We also investigated the effect of pefloxacin on the activation of mouse spleen cells by Concanavalin A (Con A) in vitro, without detecting any interference on the proliferative response or IFN-gamma production.

A one-year survey of respiratory and urinary pathogens and their antimicrobial susceptibility.

A one-year (1993) survey of the distribution of pathogens causing respiratory and urinary infections and their antimicrobial susceptibility was performed. The most common bacteria isolated from the lower respiratory tract of patients in a district general hospital were Pseudomonas aeruginosa (35.9%) and Staphylococcus aureus (21.4%). About half of the Pseudomonas strains revealed a resistance to imipenem and gentamicin, whereas almost all Staphylococcus strains were resistant to penicillin G. The most common isolates from urine of in and out-patients were Escherichia coli (32.3% and 39.8%) and Enterococcus faecalis (16.6% and 14.2%). Escherichia coli strains were largely susceptible to almost all chemoantibiotics tested, whereas Enterococcus faecalis demonstrated a high resistance pattern. Pseudomonas aeruginosa isolated from urine were more sensitive to chemoantibiotics than respiratory strains and the susceptibility of Staphylococcus aureus isolated from hospitalized or out-patients was different. A periodic monitoring system devised to give information about the circulation of bacteria and the chemoantibiotic resistance in a local context would be useful to assess the local trends and select drugs for therapy.

Antibody-dependent cytotoxic activity on human cancer cells expressing UK 114 tumor membrane antigen.

The monoclonal antibody (P-3 mAb) and the rabbit immune sera (RIS) recognizing a 14 kDa perchloric acid soluble protein extracted from goat liver (UK 114), locate this antigen on the cell membrane of several human cancer cell lines. UK 114-positive cells (e.g. HT 29 and KATO VI cells) undergo antibody-dependent cytolysis bl vitro. In nu/nu mice bearing xenografted HT 29 cells, tumor growth was markedly impaired by peri-tumoral injection of anti-UK 114 antibodies. These experiments suggest that human tumors expressing UK 114 over the cell membrane may undergo antibody-mediated cytolysis and growth control.

Group A streptococci: evaluation of in vitro resistance to two macrolides.

In recent years an increase in severe group A streptococcal infections has been observed. The possible relation between the failure of therapy and an increase of resistance to antibiotics, which are often used for streptococcal infections (clarithromycin and erythromycin), has been assessed in vitro. Streptococcus pyogenes strains tested for susceptibility were isolated in different years from pharyngotonsillar swabs of symptomatic children and typed; another nine strains came from the American Type Culture Collection. The evaluation of antimicrobial activity demonstrated that the percentage of resistance of these bacteria to the two macrolides was 4, 4.4 and 15.5%, respectively, for strains isolated in 1990, 1991 and 1994. Clarithromycin showed a better antistreptococcal, above all bactericidal, activity. The presence of M protein in streptococci does not seem to modify the kinetic activity of the two drugs, while a slower bactericidal effect was observed against capsulated strains. The resurgence of severe group A Streptococcus infections may be due to an increase in the circulation of strains with a capsule expression, which is critical also for resistance to phagocytic killing.

Evaluation of the diagnostic accuracy of a kit for the rapid detection of group A streptococci.

A rapid immunoassay method using an Event Test Strip Strep A experimental kit (Boehringer Mannheim) was evaluated. Results obtained were compared with culture results to evaluate the accuracy of detection of group A streptococci directly from throat swabs or from artificial swabs containing various bacterial concentrations. A good diagnostic accuracy was obtained with a sensitivity of 96.9% in the assay of throat swabs which provided more than ten group A Streptococcus colonies per plate. Since a low level of micro-organisms may indicate infection, it is recommended that a culture be performed when the rapid test based on antigen detection is negative.

Evaluation of virulence factors and the adhesive capability of Escherichia coli strains.

Escherichia coli strains recently isolated from adult women with recurrent urinary tract infection (R-UTI) were compared with strains from women with non-recurrent infections (UTI). Haemolysin and mannose-resistant (MR) haemagglutinin were more prevalent in the first group. Using a spectrophotometric technique with biotinylated bacteria, the ability of bacteria to adhere to uroepithelial cells was related to this last character. R-UTI strains are also more resistant to the phagocytic activity of U937 cells. This could relate in vivo to a resistance to mucosal phagocytes, so as to prevent host defence mechanisms.