Relationship between Tibial conformation, cage size and advancement achieved in TTA procedure

Background

Previous studies have suggested that there is a theoretical discrepancy between the cage size and the resultant tibial tuberosity advancement, with the cage size consistently providing less tibial tuberosity advancement than predicted. The purpose of this study was to test and quantify this in clinical cases. The hypothesis was that the advancement of the tibial tuberosity as measured by the widening of the proximal tibia at the tibial tuberosity level after a standard TTA, will be less than the cage sized used, with no particular cage size providing a relative smaller or higher under-advancement, and that the conformation of the proximal tibia will have an influence on the amount of advancement achieved.

Results

One hundred sixty-four dogs met the inclusion criteria. The mean percentage under-advancement was 15.5%. All dogs had an advancement less than the stated cage size inserted. An association between the proximal tibial tuberosity angle (increased in cases with low patellar tendon insertion), and percentage under-advancement was found, with an increase of 0.45% under-advancement for every 1 degree increase in angle a (p = 0.003). There was also evidence of a difference between the mean percentage under-advancement in breeds (p = 0.001) with the Labrador having the biggest under-advancement. Cage size (p = 0.83) and preoperative tibial plateau angle (p = 0.27) did not affect under-advancement.

Conclusions

The conformation of the tibial tuberosity and therefore the relative cage positioning have an impact on mean percentage under-advancement of the tibial tuberosity after standard TTA. In all evaluated cases, the advancement of the tibial tuberosity was less than intended by the cage size selected.

Can They Do Anything? Ten Single-Subject Studies of the Engagement Level of Hospitalized Demented Patients

The authors used a time-sampling method and a single-case experimental design to see if 10 hospitalized demented patients were more engaged during activity sessions than when they were on the wards. They all participated more fully in the activity sessions. There was some improvement on the Clifton Assessment Procedure for the Elderly scores during phase B when the patients were attending the activity sessions, but it was small and might be attributed to other factors. The individual patients varied greatly in their participation and choice of activities, despite their infirmities.

Antimicrobial susceptibilities of Pasteurella strains isolated from humans

The in vitro susceptibilities of 192 consecutive clinical strains of Pasteurella spp. isolated between 1996 and 2003 from soft tissue pus (n = 146), respiratory tract specimens (n = 38) and blood (n = 8) were studied by an agar dilution method. All isolates were susceptible to minocycline, cefotaxime, ofloxacin, ciprofloxacin and levofloxacin. Most strains were susceptible to moxifloxacin, amoxicillin, azithromycin and clarithromycin, whereas lower susceptibility rates to telithromycin (89.4%) were observed among respiratory tract isolates.

Validation of diffusion methods for macrolide susceptibility testing of Helicobacter pylori

Helicobacter pylori resistance to macrolides is increasing, and the need for susceptibility testing has become crucial. The only standardized method is agar dilution, which is not adapted to clinical practice. The present work aimed: (1) to optimize the technical conditions and to assess the reproducibility of the E-test and disk diffusion method for macrolides susceptibility testing of H. pylori, and (2) to assess the performances of these two phenotypic methods in detecting strains harboring a resistance mechanism to macrolides. We used 191 isolates collected in nine centers of France and Belgium. Phenotypic tests were performed on Mueller-Hinton agar supplemented with 10% horse blood, inoculated with a 2-day-old H. pylori suspension (10(8) CFU/ml), and incubated for 72 hr at 37 degrees C under microaerophilic conditions. The reproducibility studied on two randomly selected strains was better for disk diffusion than for the E-test for both clarithromycin and erythromycin. For a subset of 10 strains, the MICs of erythromycin and clarithromycin did not differ from more than one two-fold dilution when determined by E-test or agar dilution method. The breakpoints were for MICs: 1 mg/L for both clarithromycin and erythromycin and for inhibition diameters, 22 mm for clarithromycin and 17 mm for erythromycin. There was a 100% concordance between susceptibility to erythromycin and clarithromycin. However, the susceptible and resistant populations were better separated by testing erythromycin. Of 34 resistant strains, two lacked the A2142G and A2143G point mutations in 23S rRNA by PCR-RFLP. None of 15 tested sensitive strains were positive for one of these two point mutations. For clinical practice, we recommend to assess macrolide susceptibility of H. pylori by using one of these two phenotypic methods under the described technical conditions.

Gastric penetration of amoxicillin in a human Helicobacter pylori-infected xenograft model

The delivery of antibiotics into Helicobacter pylori-infected human stomachs is still poorly understood. Human embryonic gastric xenografts in nude mice have recently been proposed as a new model for the study of H. pylori infection. Using this model, we compared the penetration of amoxicillin, after intraperitoneal administration of a dose of 20 mg/kg of body weight, into the gastric mucosae of infected and uninfected xenografts. The concentrations of this drug in serum and superficial gastric mucosae were determined at 20 min and 1 and 3 h after injection. Ten mice with H. pylori-infected grafts (n = 5) or uninfected grafts (n = 5) were studied. Mucosal samples were obtained by cryomicrotomy. The concentrations in serum were similar to those obtained in the serum of humans after oral administration of 1 g of amoxicillin. The mean area under the tissue concentration-versus-time curve from 0 to 3 h obtained for mice with infected grafts was significantly higher than that obtained for the animals with uninfected grafts (P = 0.01). These results suggest that the penetration of amoxicillin into the superficial gastric mucosa may be substantially increased in the case of H. pylori infection. Thus, human xenografts in nude mice represent a new, well-standardized model for investigation of systemic delivery of drugs into H. pylori-infected gastric mucosa.

Human embryonic gastric xenografts in nude mice: a new model of Helicobacter pylori infection

In vitro or animal models have been used to investigate the pathogenesis of Helicobacter pylori infection. However, extrapolation to humans of results obtained with these heterologous models remains difficult. We have developed a new model for the study of H. pylori infection that uses human entire embryonic stomachs engrafted in nude mice. At 80 days after implantation, 22 of these xenografts, which exhibited a mature gastric epithelium, were inoculated with 10(7) to 10(8) CFU of either H. pylori LB1, a freshly isolated H. pylori strain (n = 12), or H. pylori ATCC 49503 (n = 10). After 12-week examination, H. pylori LB1 persistently colonized the antrum of all inoculated grafts, as assessed by culture (mucus and mucosa), immunohistochemistry (mucosa), and a rapid urease test (mucus). H. pylori ATCC 49503, either before or after in vivo passage, permitted only a transient 2-week colonization in one of the five inoculated grafts in both groups. Colonization was always associated with an increase of gastric juice pH. A mild neutrophil infiltration of the gastric mucosa was noted solely in infected grafts. Transmission electron microscopy showed adherence of H. pylori organisms to epithelial cell surface. In six animals, intracytoplasmic location of this bacterium was observed in the antrum or the fundus. These results allow us to propose this model as a new ex vivo model for the study of specific H. pylori-gastric cell interactions.

Streptococcal cell wall-induced arthritis: requirements for IL-4, IL-10, IFN-gamma, and monocyte chemoattractant protein-1

Intra-articular injection of streptococcal cell wall Ag followed by i.v. challenge ("reactivation") results in a destructive lymphocyte-dependent monoarticular arthritis. To further define the role of immune mechanisms in the model, Abs to Th1 and Th2-related cytokines were evaluated. Treatment of rats with antibodies to IL-4 reduced swelling, while treatment with anti-IL-10 or anti-IFN-gamma either had no effect or slightly enhanced the inflammatory response. These results suggest that Th-2 immune mechanisms may be, at least in part, operative in the model. To more precisely define the role of IL-4, the effects of anti-IL-4 on monocyte chemoattractant protein-1 (MCP-1) expression were evaluated. Initial studies demonstrated that mRNA (as determined by in situ hybridization) and protein (as determined by immunofluorescence) for MCP-1 were detectable in inflamed synovial tissue in a time-dependent manner. Anti-IL-4 treatment significantly reduced the expression of mRNA for MCP-1 24 and 72 h after reactivation. In addition, anti-MCP-1 inhibited swelling and reduced influx of (111)In-labeled T cells. These data suggest that the reactivation model of streptococcal cell wall Ag-induced arthritis is Th-2 dependent, and that an inter-relationship exists between IL-4 and the expression of MCP-1.

Differential quantitative blood cultures in the diagnosis of catheter-related sepsis in intensive care units

The aim of this prospective study was to compare differential blood cultures and quantitative catheter tip cultures for the diagnosis of catheter-related sepsis. Over a period of 2 years, 283 central venous catheters were inserted in 190 adult patients. Catheters were removed when they were no longer needed or when infection was suspected. Immediately before removal of the central venous catheters, blood cultures were performed, with blood drawn simultaneously from the catheter and the peripheral vein. After removal, quantitative catheter culture was performed according to the Brun-Buisson modified Cleri technique. Fifty-five quantitative catheter cultures were positive. They were classified as contaminated (n = 18), colonized (n = 23), or infected (n = 14). Differential blood cultures correctly identified 13 infections. With a catheter/peripheral cfu ratio of 8, differential blood cultures had a sensitivity of 92.8% and a specificity of 98.8%. When the catheters were removed because of suspected infection, differential blood cultures had a sensitivity of 92.8% and a specificity of 100%. Differential blood culture, a technique that does not necessitate catheter removal, seems effective in the diagnosis of catheter-related sepsis in patients in the intensive care unit.

Streptococcal cell wall-induced arthritis. Requirements for neutrophils, P-selectin, intercellular adhesion molecule-1, and macrophage-inflammatory protein-2

Immune arthritis in rat ankle joints was induced by intra-articular injection of streptococcal cell was extract (SCW), followed 21 days later by i.v. injection of SCW. This results in a monoarticular arthritis characterized by an influx of neutrophils and mononuclear cells, a 35-fold increase in urinary excretion of 8-hydroxy-deoxyguanosine (8-OH-dGUA; an index of free radical production), ankle edema, and joint damage/destruction. Neutrophil depletion substantially reduced the intensity of ankle edema. Ab-induced blockade of P-selectin or ICAM-1 also reduced the intensity of ankle edema and the influx of neutrophils. Blockade of TNF-alpha or IL-1 resulted in nearly complete and persistent reduction in ankle edema and profound reductions in the accumulation of neutrophils and mononuclear cells in affected joints. Finally, blocking of macrophage-inflammatory protein-2 reduced ankle edema and neutrophil accumulation during the first 2 days after i.v. challenge with SCW. These data indicate that SCW-induced arthritis is neutrophil dependent and that the recruitment of neutrophils and subsequent joint edema requires ICAM-1, P-selectin, and macrophage-inflammatory protein-2, as well as TNF-alpha and IL-1.

Streptococcal cell wall-induced arthritis. Requirements for neutrophils, P-selectin, intercellular adhesion molecule-1, and macrophage-inflammatory protein-2

Immune arthritis in rat ankle joints was induced by intra-articular injection of streptococcal cell was extract (SCW), followed 21 days later by i.v. injection of SCW. This results in a monoarticular arthritis characterized by an influx of neutrophils and mononuclear cells, a 35-fold increase in urinary excretion of 8-hydroxy-deoxyguanosine (8-OH-dGUA; an index of free radical production), ankle edema, and joint damage/destruction. Neutrophil depletion substantially reduced the intensity of ankle edema. Ab-induced blockade of P-selectin or ICAM-1 also reduced the intensity of ankle edema and the influx of neutrophils. Blockade of TNF-alpha or IL-1 resulted in nearly complete and persistent reduction in ankle edema and profound reductions in the accumulation of neutrophils and mononuclear cells in affected joints. Finally, blocking of macrophage-inflammatory protein-2 reduced ankle edema and neutrophil accumulation during the first 2 days after i.v. challenge with SCW. These data indicate that SCW-induced arthritis is neutrophil dependent and that the recruitment of neutrophils and subsequent joint edema requires ICAM-1, P-selectin, and macrophage-inflammatory protein-2, as well as TNF-alpha and IL-1.

Setting handicap goals with elderly people: a pilot study of the Life Strengths Interview

OBJECTIVE

To assess whether the Life Strengths Interview (LSI) is a useful clinical framework to identify handicap goals.

DESIGN

Clinical case studies.

SETTINGS

Two elderly care rehabilitation hospitals.

SUBJECTS

Five people, whose ages ranged from 73 to 90 years. All participants were aware of their likely resultant disability, scored 25+ out of a possible 30 with the Mini-Mental State Examination, were able to communicate effectively and were due to be discharged home in approximately one month.

INTERVENTIONS

Each participant undertook the LSI process with the research occupational therapist.

MAIN OUTCOME MEASURES

Identified rehabilitation goals and their achievement.

RESULTS

Goals were focused around families and other support networks. Six to eight weeks following discharge, achievement of goals varied.

CONCLUSIONS

This pilot study suggests that the LSI may be a useful clinical framework but further research needs to investigate whether a modified clinical version may be more suitable.

Evaluation of Pyloriset Dry, a new rapid agglutination test for Helicobacter pylori antibody detection

We evaluated the performance of a new latex agglutination test, Pyloriset Dry (Orion Diagnostica, Espoo, Finland), in the simultaneous detection of immunoglobulin G (IgG), IgA, and IgM antibodies to Helicobacter pylori and compared it with that of the Pyloristat test (BioWhittaker, Fontenay-sous-Bois, France), an enzyme-linked immunosorbent assay detecting IgG to H. pylori, for 96 untreated dyspeptic patients who had undergone gastroduodenal endoscopy. Infection was diagnosed in 56 cases by positive culture and/or positive Giemsa stain and rapid urease test (antral biopsies) and was associated with chronic gastritis in 52 patients. Forty noninfected patients did not have chronic gastritis. The sensitivity of Pyloriset Dry was 91.1%. The sensitivity of Pyloristat was 91.1 or 82.1%, depending on whether equivocal results were considered positive or negative, respectively. Both tests had a specificity of 87.5%. Their performances were not statistically different. Thus, Pyloriset Dry is an alternative to serological tests for adults, particularly when a small number of serum samples has to be tested.

[In vitro susceptibility of Pasteurella and related bacteria to five orally administered antibiotics]

Tetracyclines and beta-lactam antibiotics are usually recommended for the treatment of pasteurellosis following bite wounds. However other oral antimicrobial agents could be proposed. In vitro susceptibility of 94 Pasteurella strains [P. multocida (79), P. stomatis (11), P. dagmatis (2), P. canis (1), P. "SP" (1)], 20 group EF-4 strains and 28 Neisseria weaveri strains (formerly group M-5), that are bacteria often isolated after animal-inflicted wounds, was studied towards five antibiotics: clarithromycin, azithromycin, pristinamycin, trimethoprim-sulfamethoxazole and ciprofloxacin. MICs were determined by the agar dilution method using HTM medium (Oxoïd), and for pristinamycin using both HTM and Mueller-Hinton agar supplemented with 5% horse blood (BMH). Most of Pasteurella isolates showed intermediate susceptibility to clarithromycin (63%) and to azithromycin (90.5%) with lower MICs for azithromycin. Fourty-two and thirty-two percent of Pasteurella strains were susceptible to pristinamycin respectively on HTM and on BMH. EF-4 and N. weaveri were more sensitive than Pasteurella to macrolides and to pristinamycin. Trimethoprim-sulfamethoxazole was active against all isolates, with higher MICs for EF-4 and N. weaveri. On all strains tested, the lowest MICs were observed for ciprofloxacin. Trimethoprim-sulfamethoxazole and ciprofloxacin could be proposed as a therapeutic alternative in case of pasteurellosis following animal bites.

Cytoprotective effects of CI-959 in the rat gastric mucosa: modulation of leukocyte adhesion

BACKGROUND & AIMS

CI-959 is an anti-inflammatory agent that inhibits neutrophil adhesion, respiratory burst, and mast cell histamine release in vitro. In view of the emerging role of neutrophils in gastric erosive damage, the goals of this study were to assess the gastric cytoprotective effects of CI-959 and identify the mechanism responsible for this action.

METHODS

Cytoprotective effects in the rat nonsteroidal anti-inflammatory drug and ethanol erosion models were assessed using image analysis. The in vivo effects of CI-959 on gastric acid secretion, arachidonic acid metabolism, and intracellular sulfhydryl and leukocyte adhesion were also examined.

RESULTS

CI-959 protected prophylactically against the erosive damage induced by aspirin, indomethacin, and ethanol with 50% effective doses (ED50s) of 0.05, 1.0, and 0.07 mg/kg administered orally, respectively. When administered after indomethacin or ethanol, CI-959 had no effect on the healing of erosive damage. CI-959 did not alter gastric acid secretion, arachidonic acid metabolism, or intracellular sulfhydryl levels. In vivo, CI-959 blocked leukocyte adhesion in intravital microscopy studies using indomethacin (ED50, < 5 mg/kg orally) or platelet-activating factor (50% inhibiting concentration, approximately 10 mumol/L) as the adhesion stimulus.

CONCLUSIONS

The most likely mechanism responsible for the cytoprotective effects of CI-595 is its inhibitory effects on leukocyte trafficking and/or adhesion.

Immunofluorescence quantitation of stromelysin in human synovial fibroblasts by confocal laser scanning microscopy

BACKGROUND

Elevated levels of stromelysin have been reported in humans with osteoarthritis and rheumatoid arthritis, as well as in animal models of arthritis. However, a considerable amount of heterogeneity is observed in the expression of this enzyme in pathologic tissues as well as in in vitro systems. To analyze this variability, stromelysin expression was quantitated in individual human synovial fibroblasts (HSF) obtained from osteoarthritis patients.

EXPERIMENTAL DESIGN

HSF were incubated with interleukin-1 (40 units/ml), an agonist known to induce stromelysin, in the presence or absence of dexamethasone (0.01 to 100 nM), an inhibitor of stromelysin transcription. With a stromelysin-specific antibody and a tetramethyl-rhodamine 5-isothiocyanate-labeled secondary antibody, the enzyme was visualized and the fluorescence in individual cells was quantified with an ACAS 570 laser cytometer in confocal mode.

RESULTS

Stromelysin expression varied from one cell to another; however, on the basis of the magnitude of expression of stromelysin by each cell, the "nonresponders" within each treatment were identified. Approximately 34% of the cells showed a higher level of stromelysin expression in IL-1-treated HSF compared with controls. A dose-dependent inhibition in the expression of stromelysin was observed in response to increasing concentrations of dexamethasone. The dose-dependent changes in the accumulation of stromelysin protein correlated well with the stromelysin mRNA expression.

CONCLUSIONS

Confocal laser scanning microscopy can be effectively used to analyze cellular heterogeneity in stromelysin expression.

Use of cryomicrotomy to study gastric diffusion of amoxicillin in guinea pigs

Cryomicrotomy has been used as a new technique for removing gastric mucosae from adult guinea pigs for the study of amoxicillin secretion across gastric mucosae. This method allowed a very regular thickness of the removed surface layer of mucosa to be obtained with good reproducibility. Gastric superficial mucosa concentrations and gastric juice concentrations of amoxicillin were determined 1, 2, and 4 h after intramuscular administration (50 mg/kg) in 21 guinea pigs by a microbiological method. No antibiotic was detected in gastric samples at 4 h, except for a low-level mucosal concentration in one animal, thus indicating the short time that amoxicillin is present in gastric samples.

[Comparative study of four commercialized serologic methods for the diagnosis of gastric Helicobacter pylori infection]

OBJECTIVE

Four commercially available enzyme-linked immunosorbent assays (ELISA) were evaluated for serological diagnosis of Helicobacter pylori (H. pylori) infection in 79 untreated patients.

METHODS

Infection has been diagnosed in 40 patients, in whom culture and/or urease test and histopathology from antral biopsies, were positive for H. pylori.

RESULTS

Sensitivity (Se) and specificity (Sp) of these tests, calculated with indeterminate serological results (9 patients) classified as positive (ind +) or negative (ind -), were not statistically different: GAP-test (Bio-Rad), Se = 95% (ind +), 90% (ind -), Sp = 84.6% (ind +), 89.7% (ind -); Pylori-Stat (Biowhittaker), Se = 97.5% (ind + or -), Sp = 71.8% (ind +), 71.9% (ind -); Premier H. pylori (Biomedical Diagnostics), Se = 92.5% (ind +), 90% (ind -), Sp = 84.6% (ind +), 81.2% (ind -); Cobas-Core (Roche), Se = 92.5% (ind + or -), Sp = 76.9% (ind +), 79.5% (ind -). There was a strong correlation between mucosal inflammation and H. pylori status. Discrepancies between infectious status and at least one serology result were observed in 16 patients (11 H. pylori negative and 5 H. pylori positive patients).

CONCLUSION

These 4 tests are of equivalent diagnostic value. Thus, the selection of one of them should take into account cost and practicability.

Contribution of the C-terminal domain of metalloproteinases to binding by tissue inhibitor of metalloproteinases. C-terminal truncated stromelysin and matrilysin exhibit equally compromised binding affinities as compared to full-length stromelysin

In this study, we have used high resolution gel-filtration chromatography and measurements of Ki to compare the capacity of full-length native stromelysin, C-terminal truncated stromelysin (Phe100-Pro273), and matrilysin (the only metalloproteinase spontaneously lacking a C-terminal hemopexin-like domain) to bind to the tissue inhibitor of metalloproteinases (TIMP). While prostromelysin failed to bind TIMP, active stromelysin bound to the inhibitor avidly, exhibiting an affinity for TIMP (Ki = 8.3 x 10(-10) M) essentially identical to that of active interstitial collagenase as determined by competition experiments. C-terminal truncated stromelysin also formed a higher M(r) complex with TIMP which survived gel filtration. However, when truncated stromelysin was forced to compete with its full-length parent molecule for limiting amounts of TIMP, the full-length enzyme preferentially bound to the inhibitor. Indeed, binding studies indicated a Ki of 5.95 x 10(-9) M for the truncated variant's interaction with TIMP, only 14% as tight as that of full-length stromelysin. We also examined the interaction between TIMP and matrilysin, the only metalloproteinase which naturally lacks a C-terminal domain. Promatrilysin failed to bind the inhibitor. However, active matrilysin readily bound TIMP, forming a complex that resisted separation by gel filtration. When active matrilysin was forced to compete with truncated stromelysin for limiting amounts of TIMP, both enzymes appeared to complex the inhibitor with nearly equivalent efficacy. Indeed, active matrilysin exhibited a Ki for TIMP of 4.5 x 10(-9) M, essentially identical to that of truncated stromelysin. These data indicate that, as is true for collagenase, the C-terminal domain of stromelysin contributes significantly to its capacity to bind the physiologic inhibitor, TIMP. Furthermore, since stromelysin readily processes in vitro to a C-terminal truncated form, this enzyme species, as well as the full-length metalloproteinase matrilysin, may resist inhibition by TIMP in areas of active inflammation in vivo.

Selective regulation of human neutrophil functions by the cell activation inhibitor CI-959

The cell activation inhibitor CI-959 [5-methoxy-3-(1-methylethoxy)-N-1H-tetrazol-5-ylbenzo[ b]thiophene-2- carboxamide, monosodium salt] was evaluated for its effects on human neutrophil functions. CI-959 inhibited spontaneous migration and chemotaxis toward N-formyl-methionyl-L-leucyl-L-phenylalanine (fMLP) with 50% inhibition (IC50) values of 3.6 and 3.1 microM, respectively. CI-959 also inhibited superoxide anion generation in response to C5a, fMLP, serum-opsonized zymosan (SOZ), concanavalin A (Con A), and calcium ionophore A23187 with IC50 values of 2.5, 4.7, 14.5, 5.4, and 14.8 microM, respectively. In comparison, CI-959 inhibited myeloperoxidase microM, respectively. In comparison, CI-959 inhibited myeloperoxidase release in response to C5a, fMLP, SOZ, and Con A with IC50 values of 11.6, 16.1, 7.5, and < 1.0 microM, respectively, while inhibiting the response to A23187 by only 5.5% at 100 microM. At concentrations up to 100 microM, CI-959 had no effect on the respiratory burst or degranulation in response to L-alpha-1,2-dioctanoylglycerol (DiC8) or phorbol 12-myristate 13-acetate (PMA). In addition, the compound inhibited leukotriene B4 release stimulated by fMLP and SOZ (IC50 values 4.0 and 2.5 microM, respectively), while having less activity against the A23187-stimulated response (IC50 > 100 microM). These results demonstrate that CI-959 inhibits cellular responses to stimuli that mobilize intracellular calcium. For cellular responses to inophore-mediated calcium influx, only oxygen radical production was inhibited by CI-959. CI-959 was further evaluated for its effects on neutrophil stimulus-response coupling. At 100 microM, CI-959 had no effect on human neutrophil phospholipase C or protein kinase C. CI-959 inhibited fMLP-stimulated intracellular calcium mobilization and calcium influx with IC50 values of 16.7 and 3.1 microM, respectively, and exhibited less potent calmodulin antagonist activity (IC50 = 90.5 microM). These results indicate that CI-959 may exert its stimulus- and response-specific inhibitory effects on neutrophil functions, in part, through inhibition of calcium-regulated signalling mechanisms.

The pharmacologic effects of 5-[3,5-bis(1,1-dimethylethyl)-4- hydroxyphenyl]-1,3,4-thiadiazole-2(3H)-thione, choline salt (CI-986), a novel inhibitor of arachidonic acid metabolism in models of inflammation, analgesia and gastric irritation

CI-986 is a potent inhibitor of 5-lipoxygenase and cyclooxygenase pathway product biosynthesis from rat basophilic leukemia (RBL) cells. Because metabolites from these pathways have proinflammatory properties, CI-986 was evaluated in several acute and chronic models of inflammation and hyperalgesia. The compound inhibited swelling in the carrageenan footpad edema, Mycobacterium foot-pad edema and adjuvant arthritis models of inflammation with ID40 values of 1.0, 7.7., and 7.2 mg/kg, respectively. It was roughly equivalent in potency to the standard selective cyclooxygenase inhibitor, naproxen (ID40 = 0.7, 6.3, and 3.8 mg/kg, respectively). CI-986 was also evaluated in the acetic acid induced writhing hyperalgesia assay (ID50 = 0.23 mg/kg) and was approximately equipotent with indomethacin (ID50 = 0.87 mg/kg). Although the effects of CI-986 were similar to those of standard nonsteroidal antiinflammatory drugs (NSAIDs) in the inflammation models, its gastrointestinal profile was unique. CI-986 caused no gastrointestinal irritation at doses up to 200 mg/kg in acute and chronic studies. In contrast, standard NSAIDs caused ulcers at doses of 3.7-37 mg/kg after a single dose. Moreover, CI-986 inhibited the release of LTC4 and PGE2 by gastric mucosa and reduced mucosal and vascular damage induced by oral administration of absolute ethanol to rats. These results indicate that CI-986 is a potent nonulcerogenic antiinflammatory agent with novel pharmacologic properties.

Comparative in vitro and in vivo activities of two 9-deazaguanine analog inhibitors of purine nucleoside phosphorylase, CI-972 and PD 141955

An in-parallel comparison is presented of the in vitro and in vivo properties of two 9-deazaguanine analog inhibitors of purine nucleoside phosphorylase (PNP), CI-972 [8-amino-9-deaza-9-(3-thienylmethyl)guanine] and PD 141955 [9-deaza-9-(3-thienylmethyl)guanine] (published Ki values of 0.83-8.0 and 0.08 microM, respectively). Despite structural similarities, PD 141955 was considerably more potent and active in all systems studied. The respective IC50 values for inhibition of MOLT-4 cell growth in the absence and presence of 10 microM 2'-deoxyguanosine (GdR) were greater than 50 and 5.06 microM for CI-972 and 15.4 and 0.061 microM for PD 141955. PD 141955 induced accumulation of dGTP in GdR-treated MOLT-4 and CEM cells at log-lower concentrations than were required of CI-972, and the magnitude of dGTP accumulation in PD 141955-treated T cell cultures was markedly greater (e.g. 366 vs 100 pmol/10(6) CEM cells at 10 microM). PD 141955 administered orally produced a dose-dependent elevation of plasma inosine and guanosine in rats over a broad concentration range. Mean plasma inosine concentrations following a 150 mg/kg p.o. dose peaked at 6.21 and 13.2 microM in CI-972 and PD 141955-treated rats, respectively. Low levels of inosine were detectable at 50 micrograms/kg following oral administration of PD 141955.

Differential regulation of human eosinophil, macrophage, and neutrophil functions by the allergic mediator release inhibitor CI-959

The cell activation inhibitor CI-959 [5-methoxy-3-(1-methyl-ethoxy)-N-1H- tetrazol-5-ylbenzo[b]thiophene-2-carboxamide, monosodium salt] was evaluated for its effect on the activation of human eosinophils, macrophages, and neutrophils by the phagocytic stimulus serum-opsonized zymosan (SOZ). CI-959 inhibited the respiratory burst of eosinophils and neutrophils, measured as the generation of superoxide anion, with IC50s of 9.6 and 14.5 microM, respectively. In contrast, 100 microM CI-959 inhibited superoxide anion generation by human macrophages by only 22.7%. The compound exhibited a different inhibition profile for lysosomal enzyme release from these cells. At 100 microM, CI-959 inhibited the release of eosinophil peroxidase and macrophage N-acetyl-beta-D-glucosaminidase by only 19.5 and 25.6%, respectively. In contrast, CI-959 inhibited the release of the neutrophil primary granule enzyme myeloperoxidase with an IC50 of 7.5 microM, while inhibiting release of lysozyme from secondary granules by only 11.4% at 100 microM. These results demonstrate that oxygen radical generation and lysosomal enzyme release by human leukocyte populations are differentially regulated by CI-959.

[Antibiotic sensitivity of forty-four strains of group EF4 bacteria: study of minimum inhibitory concentrations using the agar dilution method]

EF4 bacteria are found in animal saliva and may contaminate bite wounds. Minimum inhibitory concentrations of 36 antimicrobials against 44 EF4 strains were determined using dilution in Mueller-Hinton agar. EF4 bacteria were susceptible to aminopenicillins, carboxypenicillins, ureidopenicillins, third-generation cephalosporins, fluoroquinolones, rifampicin, and trimethoprime-sulfamethoxazole. Susceptibility was intermediate for penicillin G, low for macrolides and variable for aminoglycosides. EF4 bacteria were resistant to lincomycin and trimethoprime. Routine prophylactic treatment of bite-induced Pasteurella infections using an aminopenicillin or a cycline also protects against EF4 infection of the wound.

Inhibition of interleukin-2 production and lymphocyte responsiveness by the cell activation inhibitor, CI-959

CI-959 (5-methoxy-3-(1-methylethoxy)-N-1H-tetrazol-5-yl-benzo [b]-thiophene-2-carboxamide), an antiallergy compound, blocked release of IL-2 from Con A stimulated rat splenocytes and human lymphocytes with respective IC50s of 19.1 and 23.1 microM. Inhibition of IL-2 production required the presence of CI-959 in culture medium for the first 9 hr. CI-959 also inhibited Con A-stimulated rat and human lymphocyte proliferation with IC50s of 4.7 and 5.4 microM, respectively. Inhibition of the Con A proliferative response could not be overcome by exogenous recombinant human IL-2 (300 units/ml) in either the rat or human systems. Although potent in the human mixed lymphocyte reaction (IC50 = 3.5 microM), CI-959 was less effective in blocking the PHA response (IC50 = 43.9 microM), and had minimal effect on the release of IL-1 and TNF alpha from LPS-stimulated human monocytes. These findings suggest that CI-959 selectively inhibits some lymphocyte functions, as opposed to monocyte functions, and that among these is the production of IL-2.

Selective in vitro inhibition of human MOLT-4 T lymphoblasts by the novel purine nucleoside phosphorylase inhibitor, CI-972

CI-972 (2,6-diamino-3,5-dihydro-7-(3-thienylmethyl)-4H-pyrrolo[3,2- d]pyrimidin-4-one monohydrochloride, monohydrate) is a competitive inhibitor of PNPase (E.C. 2.4.2.1., Ki = 0.83 microM) entering clinical trials as a T cell-selective immunosuppressive agent. Neither CI-972 (less than or equal to 50 microM) nor dGuo (less than or equal to 10 microM) inhibited [3H]Thd uptake by human MOLT-4 (T cell) or MGL-8 (B cell) lymphoblasts, but in the presence of 10 microM dGuo, the IC50 for CI-972 decreased to 3.0 microM for MOLT-4 but remained at greater than 50 microM for MGL-8. Inhibition of MOLT-4 growth was associated with an increase in dGTP that was dependent on CI-972 concentration and inhibited by 2'-deoxycytidine. Growth could not be restored by hypoxanthine or adenine. No alterations in GTP pools were noted in MOLT-4, and neither GTP nor dGTP were altered in MGL-8.

Novel thiophene-, pyrrole-, furan-, and benzenecarboxamidotetrazoles as potential antiallergy agents

The synthesis and antiallergic activity of a series of novel thiophene-, pyrrole-, furan-, and benzenecarboxamidotetrazoles are described. A number of compounds inhibit the release of histamine from anti-IgE-stimulated human basophils. Optimal inhibition is exhibited in compounds with a 3-alkoxy, a 4-halo, and a 5-methyl, 5-methoxy, or 5-bromo on a thiophene-2-carboxamidotetrazole.

Biochemical and pharmacological properties of CI-972, a novel 9-deazaguanine analog purine nucleoside phosphorylase (PNP) inhibitor

CI-972 (2,6-diamino-3,5-dihydro-7-(3-thienylmethyl)-4H-pyrrolo[3, 2-d]pyrimidin-4-one monohydrochloride, monohydrate) is a novel inhibitor of PNP (Ki = 0.83 microM) under development as a T cell-selective immunosuppressive agent. CI-972 inhibited proliferation (3H-thymidine uptake) of human MOLT-4 (T cell) but not MGL-8 (B cell) lymphoblasts with respective IC50s of 3.0 and greater than 50 microM when tested with 10 microM 2'-deoxyguanosine. Without addition of exogenous 2'-deoxyguanosine, CI-972 was not inhibitory to any human T or B lymphoblastoid cell line tested. 2'-Deoxycytidine (10 microM), but not hypoxanthine or adenine, restored MOLT-4 cell growth. Inhibition of 3H-thymidine uptake in MOLT-4 cells correlated with accumulation of dGTP, while alterations in guanine nucleotides were not observed. 2'-Deoxycytidine (10 microM) also blocked dGTP accumulation in MOLT-4 cells. CI-972 showed activity in vivo over a broad dose range: At 5-150 mg/kg p.o., CI-972 produced dose-dependent elevation of plasma inosine one hr after administration to rats (mean maximum of 2.62 vs. 0.06 microM in controls). Guanosine was also significantly elevated in a concentration-dependent manner, although the effect was not as impressive. Plasma nucleosides remained statistically-significantly elevated for up to four hr following a single oral dose of CI-972.

Inhibition of human neutrophil activation by the allergic mediator release inhibitor, CI-949

The allergic mediator release inhibitor Cl-949 [5-methoxy-3-(1-methylethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H -indole-2-carboxamide, L-arginine salt] was evaluated for its effects on human neutrophil functions. Cl-949 (100 microM) inhibited spontaneous migration and chemotaxis toward f-met-leu-phe (FMLP) by 49.1% and 45.8%, respectively. At the same concentration, Cl-949 inhibited the phagocytosis of serum-opsonized zymosan (SOZ) by 39.0%. Cl-949 inhibited leukotriene B4 and thromboxane B2 release in response to SOZ with IC50s of 2.0 microM and 3.3 microM, while inhibiting the response to FMLP with IC50s of 1.7 and 2.0 microM. Cl-949 also inhibited myeloperoxidase release from primary lysosomal granules in response to the following stimuli with the respective IC50s (microM): C5a (40.3); FMLP (34.4): SOZ (21.4); concanavalin A (Con A) 3.9); and calcium ionophore A23187 (91.2). In contrast, Cl-949 inhibited lysozyme release from secondary granules in response to SOZ and Con A with IC50s of 99.3 and 56.1 microM, while inhibiting the response to C5a, FMLP, and A23187 by 41.2%, 52.4%, and 10.0%, respectively, at 100 microM. Cl-949 (100 microM) had no inhibitory effect against lysozyme release in response to L-alpha-1,2 dioctanoylglycerol (DiC8), or phorbol 12-myristate 13-acetate (PMA). Cl-949 inhibited superoxide anion generation stimulated by FMLP and Con A with IC50s of 33.9 and 25.8 microM, while inhibiting the response to C5a, SOZ, and A23187 by 36.6%, 24.8%, and 14.1% and having no effect on the response to DiC8 or PMA at 100 microM. These results demonstrate preferential inhibition of arachidonic acid metabolism and degranulation of primary lysosomal granules by Cl-949 with selectivity for stimuli which promote intracellular calcium mobilization or calcium influx.

Inhibition of histamine, leukotriene C4/D4, and thromboxane B2 release from human leukocytes and human chopped lung mast cells by the allergic mediator release inhibitor, CI-949

The novel antiallergy compound, 5-methoxy-3-(1-methylethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H- indole-2- carboxamide, L-arginine salt (CI-949), inhibited mediator release from human basophilic leukocytes and from human chopped lung mast cells challenged with anti-IgE. In leukocytes, CI-949 was a more potent inhibitor of leukotriene C4/D4 and thromboxane B2 release (concentration of drug that inhibits mediator release by 50% [IC50] 0.5 and 0.1 mumol/L, respectively) than of histamine (IC50, 11.4 mumol/L) when anti-IgE was the challenging stimulus. In human lung, inhibition of release of all three mediators occurred at approximately equal concentrations (IC50s for histamine, 16.6 mumol/L; for leukotriene C4/D4, 7.1 mumol/L; and for thromboxane B2, 6.2 mumol/L). The inhibition of histamine release from basophils by CI-949 was further characterized using a variety of stimuli. Challenge with anti-IgE, histamine-releasing factor derived from lymphocytes, N-formyl-L-methionyl-L-leucyl-L-phenylalanine, and concanavalin A revealed potent inhibition (IC50, 10 to 15 mumol/L). CI-949 was less potent versus calcium ionophore A23187, phorbol myristate acetate (12-o-tetradecanoylphorbol-13-acetate), and C5a (IC50s, 30, 54, and 60 mumol/L, respectively). These results suggest that diverse pathways of cell activation-excitation coupling exist for different stimuli in basophils. Furthermore, the activity and potency of CI-949 in inhibiting release of histamine, leukotrienes, and thromboxane from both human basophils and mast cells suggest that the compound will be effective clinically for indications in which these mediators are implicated, including asthma and allergic rhinitis.

Differential regulation of the activation of human eosinophils, macrophages, and neutrophils: effect of the allergic mediator release inhibitor CI-949

The allergic mediator release inhibitor CI-949 [5-methoxy-3-(1- methylethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H-indole-2-carbox amide L-arginine salt] was evaluated for its effect on the activation of human eosinophils, macrophages, and neutrophils by the phagocytic stimulus serum-opsonized zymosan (SOZ). CI-949 inhibited the SOZ- stimulated respiratory burst of eosinophils, measured as the generation of superoxide anion, with an IC50 of 22.8 microM. At concentrations of 100 microM, CI-949 had no inhibitory effect against lysosomal enzyme release by these cells. At 100 microM, CI-949 had no inhibitory effect against release of eosinophil peroxidase while inhibiting release of the macrophage lysosomal enzyme N-acetyl-beta-D- glucosaminidase by only 11.7 percent. In contrast, CI-949 inhibited the release of the neutrophil primary granule enzyme myeloperoxidase inhibiting of 21.4 microM, while inhibiting release of lysozyme from lysosomal enzyme release from secondary granules with an IC50 of 99.3 microM. These results demonstrate that oxygen radical generation and lysosomal enzyme release by human eosinophils, macrophages and neutrophils are differentially regulated by CI-949. These results suggest that these inflammatory cells may have distinct stimulus-related coupling mechanisms.

Inhibition of human neutrophil activation by the allergic mediator release inhibitor, CI-949: mechanism of inhibitory activity

CI-949 [5-methyl-3-(1-methylethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H- indole-2- carboxamide, L-arginine salt] inhibits human neutrophil activation in response to stimuli which promote calcium mobilization or calcium influx. This report further examines the effect of CI-949 on phosphoinositide-dependent stimulus-response coupling. At 100 microM, CI-949 had no inhibitory effect on human neutrophil phospholipase C or protein kinase C. In contrast, CI-949 inhibited FMLP-stimulated intracellular calcium mobilization with an IC50 of 8.4 microM. The compound was also a potent calmodulin antagonist, inhibiting calmodulin-dependent phosphodiesterase activity with an IC50 of 31.0 microM. The calmodulin antagonist activity of CI-949 was confirmed by fluorescence spectroscopy. These results demonstrate that CI-949 may function through inhibition of calcium- and calmodulin-dependent signal transduction processes.

CI-949: a new, potential antiallergy compound inhibits antigen-induced allergic reactions in guinea-pigs in vitro and in vivo

CI-949 (5-methoxy-3-(1-methyl-ethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H -indole-2-carboxamide) effectively inhibited the release of histamine and the synthesis or release of immunoreactive sulfidopeptide leukotrienes C4-D4 and thromboxane B2 from antigen-challenged lung fragments of of actively sensitized guinea-pigs. The IC50s were 26.7 +/- 2.8 microM for histamine, 2.7 +/- 2.4 microM for leukotriene, and 3.0 +/- 1.8 microM for thromboxane. Drugs including ketotifen, cromolyn and nedocromil did not inhibit histamine release or did so only at high concentrations, and only cromolyn inhibited the synthesis or releases of the 2 eicosanoids. A dose of 50 mg/kg i.p. of CI-949 protected conscious, aerosol-allergen challenged guinea-pigs for at least 1 h and 100 mg/kg i.p. or per os protected for at least 2 h. These results, the comparisons to standard antiallergic drugs, and other data from experiments with human lung fragments and isolated peripheral leukocytes 1,2,3,4 suggest that CI-949 should be evaluated for clinical activity against allergic and inflammatory conditions in which histamine, sulfidopeptide leukotrienes, and/or thromboxane mediate symptoms.

CI-959, a new, potential antiallergic drug, inhibits mediator release from lung and contractions of human airways in vitro

Many symptoms of the immediate allergic response can be attributed to the synthesis/release and subsequent actions of histamine and metabolic products of arachidonic acid oxidation. CI-959 [5-methoxy-3-(1-methylethoxy)-N-1H-tetrazole-5-yl-benzo(b) thiophene-2-carboxamide], a new, potential antiallergic drug, inhibited the release of histamine, immunoreactive sulfidopeptide leukotrienes C4, D4 and E4 and immunoreactive thromboxane B2 from immunologically activated guinea-pig and human lung cells in vitro. The IC50s of CI-959 using guinea-pig lung were: histamine, 0.8 +/- 1.4 microM; leukotriene, 0.7 +/- 1.6 microM and thromboxane, 9.6 +/- 3.3 microM. Using human lung the IC50s were: 2.3 +/- 1.3 microM for histamine; 0.3 +/- 5.1 microM for leukotriene, and 0.3 +/- 2.6 microM for thromboxane. CI-959 caused a concentration-dependent inhibition of anti-IgE-induced contractions of human bronchial muscle. Mean percent inhibitions were 45, 65 and 96 at 1, 3 and 10 microM, respectively. Cromolyn, 10 microM, inhibited bronchial contractions only 42%. The ability of CI-959 to inhibit these immunologically induced contractions indicates that the release of all mediators responsible for bronchoconstriction was effectively inhibited. These data suggest that CI-959 may be effective in preventing the development of symptoms directly related to inflammatory mediator release in a variety of allergic and inflammatory states.

Novel indolecarboxamidotetrazoles as potential antiallergy agents

The synthesis and antiallergic potential of a series of novel indolecarboxamidotetrazoles are described. A number of compounds inhibit the release of histamine from anti-IgE-stimulated basophilic leukocytes obtained from allergic donors. Optimal inhibition is exhibited by compounds with 3-alkoxy, 5-methoxy, and 1-phenyl substituents on the indole core structure. Compound 8d (5-methoxy-3-(1-methylethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H -indole-2-carboxamide; designated CI-949) is a potent inhibitor of histamine release from human basophils and from guinea pig and human chopped lung.

In vitro effects of the antiallergy compound, CI-949, on interleukin-1 and 2 release, and on mitogen and alloantigen responsiveness

CI-949 (5-methoxy-3-(1-methylethoxy)-1-phenyl-N-1H-tetrazol-5-yl-1H -indole- 2-carboxamide, L-arginine salt), an antiallergy compound, was found to be a weak inhibitor of IL-1 release from LPS-stimulated murine peritoneal exudate cells and human peripheral blood leukocytes, with IC50S of 186.2 and 267.9 microM, respectively. CI-949 was also a poor inhibitor of release of IL-2 from Con A-stimulated rat splenocytes (37% inhibition at 100 microM). CI-949 did produce concentration-related inhibition of the response of human lymphocytes to PHA and Con A (IC50S = 44.7 and 21.5 microM, respectively) as well as in the mixed lymphocyte reaction (MLR) (IC50 = 16.8 microM). The clinical significance of these latter findings is unknown at present.

Inhibition of human neutrophil activation by the allergic mediator release inhibitor, CI-922: mechanism of inhibitory activity

3,7-Dimethoxy-4-phenyl-N-1H tetrazol-5-yl-4H-furo[3,2-b]-indole-2- carboxamide, L-arginate (CI-922) is a potent inhibitory of human neutrophil functions in response to a variety of stimuli. In this report, the effects of CI-922 on specific processes involved in stimulus-response coupling are evaluated. CI-922 does not inhibit human neutrophil phospholipase C or protein kinase C activities. CI-922 is shown to inhibit calmodulin-dependent enzyme activation. The calmodulin antagonist activity is confirmed by calmodulin-Sepharose affinity chromatography. These results suggest that CI-922 inhibits neutrophil activation by preventing the activation of calmodulin-dependent enzymes, implying a critical role for such enzymes in stimulus-response coupling.

Inhibition of human neutrophil activation by the allergic mediator release inhibitor, CI-922: differential inhibition of responses to a variety of stimuli

The allergic mediator release inhibitor 3,7-dimethoxy-4-phenyl-N-1H-tetrazol-5-yl-4H-furo[3,2-b]indole-2- carboxamide, L-arginate (CI-922) is a potent inhibitor of human neutrophil functions in vitro. Over a concentration range from 1 to 100 mumol CI-922 inhibits the chemotactic response of neutrophils to the synthetic chemotaxin N-formyl-methionyl-leucyl-phenylalanine (FMLP). CI-922 also inhibits respiratory and secretory responses of neutrophils in response to agents that stimulate phospholipase C-dependent phosphoinositide hydrolysis to generate the second messengers inositol 1,4,5, trisphosphate and 1,2 diacylglycerol, including: the plasma membrane receptor-specific ligands FMLP and C5a; serum-opsonized zymosan; concanavalin A; and the guanine nucleotide regulatory protein-specific stimulus guanosine-5'-0-(3-thiotriphosphate) (GTP gamma S). CI-922 also inhibits neutrophil functions stimulated by the calcium ionophore A23187. In contrast, CI-922 does not inhibit neutrophil responses to protein kinase C-specific stimuli such as phorbol 12-myristate 13-acetate (PMA) or L-alpha-1,2 dioctanoylglycerol (DiC8). CI-922 also fails to inhibit the synergistic activation of the respiratory burst by suboptimal concentrations of PMA and calcium ionophore A23187. The observation that CI-922 inhibits neutrophil responses to a variety of soluble and particulate stimuli, excluding protein kinase C-specific stimuli, allows us to postulate the site of action of the compound. We propose that CI-922 inhibits neutrophil activation at a site distal to signal transduction through the guanine nucleotide regulatory protein required for second messenger generation but proximal to phosphorylation reactions mediated by protein kinase C and calmodulin-dependent protein kinases.

Specific inhibition of phorbol ester and DiC8-induced histamine release from human basophils by the protein kinase C inhibitors, H-7 and H-9

The release of histamine and other inflammatory mediators from human basophils is triggered by numerous stimuli, including chemical, physical and receptor-mediated activators. Several mechanisms of cell activation including protein kinase C activation have been proposed to operate in these cells. We used phorbol ester and DiC8 to induce histamine release from human basophils and the protein kinase C inhibitors H-7 and H-9 to inhibit this release. Both DiC8 and TPA induced histamine release were inhibited by H-7 (ID 50 = 37 mcM) and H-9 (IC 50 = 20 mcM). However, anti-IgE, fmlp and A23187-induced histamine release were unaffected. In contrast, the calmodulin antagonists W-7 and perphenazine effectively inhibited histamine release by all five stimuli. Therefore, different biochemical pathways appear to be critical for basophil activation depending on the nature of the stimulus used.

[Antibiotic sensitivity of Pasteurella multocida and related bacteria (bacterial groups M5 and EF4). Studies of minimal inhibitory concentrations by agar dilution]

We have been isolating Pasteurella multocida and similar germs increasingly during the last few years: due to the rabies coming back in Eastern France, more consultations have been held following animal bites; samples are then taken for a bacteriologic research. We have studied their sensitivity towards 30 antibiotics. The determination of the MIC was achieved through the agar dilution method on 34 Pasteurella multocida of human origin issued after bites and expectorations, 4 EF4 and 4 M5. The Pasteurella are very sensitive to: beta-lactam antibiotics (the lowest MIC were observed for ureido-penicillins, amino-benzylpenicillins and third generation cephalosporins), chloramphenicol, cyclines and quinolones. Fosfomycin colistin and aminoglycosides are also active but with higher MIC. The macrolides have got a slow or no activity at all. The M5 are susceptible to the same antibiotics as Pasteurella but with slightly higher concentrations. Regarding EF4, minor sensitivity or resistance to penicillin G, cephalothin and cefamandole can be pointed out.

Release of histamine from human leukocytes by one preparation of IgG oligomers

In preliminary experiments aimed at investigating the effect of covalently cross-linked human myeloma subclass proteins on histamine release from human leukocytes, we observed one preparation (designated here IgG-HR) made from pooled, purified immunoglobulin G, which consistently released histamine from these cells. Dimers and trimers, but not monomers isolated from columns of Sephadex G-200 and Ultrogel AcA22 following incubation of immunoglobulin G (Nordic Laboratories) with dimethyl suberimidate, released histamine from cells of all donors tested. In contrast, cells from the same donors showed variable responsiveness to dimers of IgE (prepared by similar techniques) or to anti-IgE. IgG-HR failed to release histamine from a "basophil-rich" mononuclear cell preparation depleted of most of the erythrocytes, platelets, neutrophils and eosinophils by centrifugation through a Ficoll-Hypaque cushion. The data suggest that IgG-HR was releasing histamine indirectly from basophils by first interacting with another cell. IgG oligomers prepared from different sources of pooled, purified IgG failed to release histamine. Although we did not have sufficient IgG-HR to adequately define this releasing activity, we feel that the data represent a potentially novel, if rare, mechanism of mediator release involving basophils and another cell.