Prediction of therapeutic intensity level from automatic multiclass segmentation of traumatic brain injury lesions on CT-scans

The prediction of the therapeutic intensity level (TIL) for severe traumatic brain injury (TBI) patients at the early phase of intensive care unit (ICU) remains challenging. Computed tomography images are still manually quantified and then underexploited. In this study, we develop an artificial intelligence-based tool to segment brain lesions on admission CT-scan and predict TIL within the first week in the ICU. A cohort of 29 head injured patients (87 CT-scans; Dataset1) was used to localize (using a structural atlas), segment (manually or automatically with or without transfer learning) 4 or 7 types of lesions and use these metrics to train classifiers, evaluated with AUC on a nested cross-validation, to predict requirements for TIL sum of 11 points or more during the 8 first days in ICU. The validation of the performances of both segmentation and classification tasks was done with Dice and accuracy scores on a sub-dataset of Dataset1 (internal validation) and an external dataset of 12 TBI patients (12 CT-scans; Dataset2). Automatic 4-class segmentation (without transfer learning) was not able to correctly predict the apparition of a day of extreme TIL (AUC = 60 ± 23%). In contrast, manual quantification of volumes of 7 lesions and their spatial location provided a significantly better prediction power (AUC = 89 ± 17%). Transfer learning significantly improved the automatic 4-class segmentation (DICE scores 0.63 vs 0.34) and trained more efficiently a 7-class convolutional neural network (DICE = 0.64). Both validations showed that segmentations based on transfer learning were able to predict extreme TIL with better or equivalent accuracy (83%) as those made with manual segmentations. Our automatic characterization (volume, type and spatial location) of initial brain lesions observed on CT-scan, publicly available on a dedicated computing platform, could predict requirements for high TIL during the first 8 days after severe TBI. Transfer learning strategies may improve the accuracy of CNN-based segmentation models.Trial registrations Radiomic-TBI cohort; NCT04058379, first posted: 15 august 2019; Radioxy-TC cohort; Health Data Hub index F20220207212747, first posted: 7 February 2022.

Mesenchymal stem cells limit vascular and epithelial damage and restore the impermeability of the urothelium in chronic radiation cystitis

BACKGROUND

Cellular therapy seems to be an innovative therapeutic alternative for which mesenchymal stem cells (MSCs) have been shown to be effective for interstitial and hemorrhagic cystitis. However, the action of MSCs on chronic radiation cystitis (CRC) remains to be demonstrated. The aim of this study was to set up a rat model of CRC and to evaluate the efficacy of MSCs and their mode of action.

METHODS

CRC was induced by single-dose localized irradiation of the whole bladder using two beams guided by tomography in female Sprague-Dawley rat. A dose range of 20-80 Gy with follow-up 3-12 months after irradiation was used to characterize the dose effect and the kinetics of radiation cystitis in rats. For the treatment, the dose of 40 Gy was retained, and in order to potentiate the effect of the MSCs, MSCs were isolated from adipose tissue. After expansion, they were injected intravenously during the pre-chronic phase. Three injections of 5 million MSCs were administered every fortnight. Follow-up was performed for 12 months after irradiation.

RESULTS

We observed that the intensity and frequency of hematuria are proportional to the irradiation dose, with a threshold at 40 Gy and the appearance of bleeding from 100 days post-irradiation. The MSCs reduced vascular damage as well as damage to the bladder epithelium.

CONCLUSIONS

These results are in favor of MSCs acting to limit progression of the chronic phase of radiation cystitis. MSC treatment may afford real hope for all patients suffering from chronic radiation cystitis resistant to conventional treatments.

Contribution of CT-Scan Analysis by Artificial Intelligence to the Clinical Care of TBI Patients

The gold standard to diagnose intracerebral lesions after traumatic brain injury (TBI) is computed tomography (CT) scan, and due to its accessibility and improved quality of images, the global burden of CT scan for TBI patients is increasing. The recent developments of automated determination of traumatic brain lesions and medical-decision process using artificial intelligence (AI) represent opportunities to help clinicians in screening more patients, identifying the nature and volume of lesions and estimating the patient outcome. This short review will summarize what is ongoing with the use of AI and CT scan for patients with TBI.

HGF and TSG-6 Released by Mesenchymal Stem Cells Attenuate Colon Radiation-Induced Fibrosis

Fibrosis is a leading cause of death in occidental states. The increasing number of patients with fibrosis requires innovative approaches. Despite the proven beneficial effects of mesenchymal stem cell (MSC) therapy on fibrosis, there is little evidence of their anti-fibrotic effects in colorectal fibrosis. The ability of MSCs to reduce radiation-induced colorectal fibrosis has been studied in vivo in Sprague–Dawley rats. After local radiation exposure, rats were injected with MSCs before an initiation of fibrosis. MSCs mediated a downregulation of fibrogenesis by a control of extra cellular matrix (ECM) turnover. For a better understanding of the mechanisms, we used an in vitro model of irradiated cocultured colorectal fibrosis in the presence of human MSCs. Pro-fibrotic cells in the colon are mainly intestinal fibroblasts and smooth muscle cells. Intestinal fibroblasts and smooth muscle cells were irradiated and cocultured in the presence of unirradiated MSCs. MSCs mediated a decrease in profibrotic gene expression and proteins secretion. Silencing hepatocyte growth factor (HGF) and tumor necrosis factor-stimulated gene 6 (TSG-6) in MSCs confirmed the complementary effects of these two genes. HGF and TSG-6 limited the progression of fibrosis by reducing activation of the smooth muscle cells and myofibroblast. To settle in vivo the contribution of HGF and TSG-6 in MSC-antifibrotic effects, rats were treated with MSCs silenced for HGF or TSG-6. HGF and TSG-6 silencing in transplanted MSCs resulted in a significant increase in ECM deposition in colon. These results emphasize the potential of MSCs to influence the pathophysiology of fibrosis-related diseases, which represent a challenging area for innovative treatments.

Chronic Inflammation and Radiation-Induced Cystitis: Molecular Background and Therapeutic Perspectives

Radiation cystitis is a potential complication following the therapeutic irradiation of pelvic cancers. Its clinical management remains unclear, and few preclinical data are available on its underlying pathophysiology. The therapeutic strategy is difficult to establish because few prospective and randomized trials are available. In this review, we report on the clinical presentation and pathophysiology of radiation cystitis. Then we discuss potential therapeutic approaches, with a focus on the immunopathological processes underlying the onset of radiation cystitis, including the fibrotic process. Potential therapeutic avenues for therapeutic modulation will be highlighted, with a focus on the interaction between mesenchymal stromal cells and macrophages for the prevention and treatment of radiation cystitis.

MP3: Medical Software for Processing Multi-Parametric Images Pipelines

This article presents an open source software able to convert, display, and process medical images. It differentiates itself from the existing software by its ability to design complex processing pipelines and to wisely execute them on a large databases. An MP3 pipeline can contain unlimited homemade or ready-made processes and can be carried out with a parallel execution system. As a viewer, MP3 allows display of up to four images together and to draw Regions Of Interest (ROI). Two applications showing the strengths of the software are presented as examples: a preclinical study involving Magnetic Resonance Imaging (MRI) data and a clinical one involving Computed Tomography (CT) images. MP3 is downloadable at https://github.com/nifm-gin/MP3.

The thermal aggregation of ovalbumin as large particles decreases its allergenicity for egg allergic patients and in a murine model

Most egg-allergic children can tolerate extensively cooked eggs. Ovalbumin, a major allergen in egg whites, is prone to aggregate upon heating. This study compares ovalbumin's allergenicity when it is aggregated as large particles to ovalbumin in its native form. Immunoglobulins (Ig)-binding and the degranulation capacities of native and aggregated ovalbumin were measured with sera from egg-allergic children and from mice sensitized to native or aggregated ovalbumin. The influence of ovalbumin structure on Ig production upon sensitization and elicitation potency by challenge was also studied. We showed that heat aggregation of ovalbumin as large particles enhances IgG production and promotes IgG2a production (a shift toward the T helper 1 profile). Aggregated ovalbumin displayed lower Ig-binding and basophil-activation capacities for sera from both allergic patients and mice. This work illustrates the links between ovalbumin structure after heating and allergenicity potential using parameters from both the sensitization and elicitation phases of the allergic reaction.

Allergy to deamidated gluten in patients tolerant to wheat: specific epitopes linked to deamidation

BACKGROUND

Gluten proteins can be modified by deamidation to enhance their solubility and technological applications. However, severe allergic reactions have been reported after the consumption of food products containing deamidated gluten (DG) in subjects tolerant to wheat. This work aimed to characterize allergen profiles for these patients in comparison with those of patients allergic to wheat and to identify IgE-binding epitopes.

METHODS

Sera were obtained from 15 patients allergic to DG and from nine patients allergic to wheat proteins (WP). IgE-binding profiles were characterized both in ELISA and in a humanized rat basophilic leukaemia (RBL) cell model. Epitopes were mapped on γ- and ω2-gliadin sequences by Pepscan, and effect of glutamine/glutamic acid substitutions was studied.

RESULTS

Compared to the heterogeneous pattern of allergens detected by IgE from patients allergic to WP, responses of patients allergic to DG were homogeneous. In ELISA, all the sera displayed IgE binding to deamidated γ- and ω2-gliadins and deamidated total gliadins, frequently with high concentrations. These modified proteins induced RBL degranulation with most of the sera from DG-allergic patients. A consensus epitope was found on native γ- and ω2-gliadins (QPQQPFPQ); it was repeated several times in their sequences. The substitution of two or three glutamines of this epitope into glutamic acid at positions Q3 or Q4 and Q8 (QPEEPFPE) increased its recognition the best.

CONCLUSION

Allergy to DG is a separate entity from wheat allergy. It can be evidenced by strong IgE binding to deamidated gliadins or peptides of the type QPEEPFPE.

Assessment of allergenicity of diploid and hexaploid wheat genotypes: identification of allergens in the albumin/globulin fraction

Wheat is an important part of the daily diet of millions of people. However, this staple food is also responsible for food allergies. Ancient cultivars of wheat are gaining interest today but nothing is known about their allergenicity. Many wheat proteins have been reported as causative food allergens, including some prolamin-type gluten proteins, and salt soluble proteins of the albumin/globulin (A/G) type. The objective of this work is to obtain information about the allergenicity of the salt soluble A/G fraction of an ancient diploid cultivar compared with a standard hexaploid bread wheat cultivar using 20 sera from patients with wheat allergy. Differences in the IgE reactivity of sera towards the two genotypes were quantified by ELISA. Qualitative differences in IgE-binding proteins were searched after 1D or 2D electrophoresis. For most of the sera, the concentration in A/G specific IgE was higher for the hexaploid T. aestivum (cv Récital) than for the diploid T. monococcum (cv Engrain). The analysis of 2D spots revealed by immunoblotting leads to the identification by mass spectrometry of 39 IgE-binding proteins, some of them unknown until now as wheat allergens. Numerous allergens were identified, differences observed between Engrain and Récital will be discussed.

Evaluation of an in vitro mast cell degranulation test in the context of food allergy to wheat

BACKGROUND

Antigenic profiles obtained by ELISA with IgE from patients with wheat food allergy (WFA) established that major allergens are albumins/globulins (AG) for children suffering from atopic eczema/dermatitis syndrome (AEDS), omega5-gliadins for adults suffering from wheat-dependent exercise-induced anaphylaxis (WDEIA), anaphylaxis or urticaria and low-molecular-weight (LMW) glutenin subunits for patients with anaphylaxis. We aimed to characterize a new mast cell transfectant for its ability to degranulate with wheat proteins and patient sera and compare these results to those obtained by ELISA.

METHODS

Thirty sera from patients with WFA were tested: 14 with AEDS (group 1) and 16 with WDEIA, anaphylaxis or urticaria (group 2). An IgE Fc receptor (FcepsilonRI) humanized rat RBL-2H3 line was established by transfection with cDNAs encoding alpha-, beta- and gamma-subunits for the human IgE receptor.

RESULTS

A humanized RBL clone was selected for its capacity to express mRNA alpha-, beta- and gamma-subunits of FcepsilonRI, to bind allergen-specific human IgE and to degranulate. In group 1, sera induced enhanced degranulation with AG extract, but rarely reacted with gliadins and glutenins. In group 2, half of the sera showed degranulation with LMW glutenins whereas the AG fraction and lipid transfer proteins were rarely positive. omega5-Gliadins did not appear as a major allergen in degranulation assays, although functional allergen-specific IgE was measurable in appreciable amounts.

CONCLUSION

Our data demonstrate that in wheat food allergen evaluation, correlation exists between mast cell degranulation and IgE measurements, depending on the type of allergen. Therefore, the biological activity of some allergen types may also be affected by other parameters.

Rheological behavior of drug suspensions in Gelucire mixtures and proxyphylline release from matrix hard gelatin capsules

Mixtures of Gelucires 50/02 and 50/13 showing different hydrophilic-lipophilic balances (HLB) and of proxyphylline were used to prepare suspensions at a concentration of 25% and to manufacture extended release hard gelatin capsules by cooling. The rheological behaviors of Gelucire mixtures with and without drug were determined by adjustment of the rheograms to the Ostwald power-law and by statistical assessment of the flow index. Pure Gelucire mixtures were very slightly shear thickening whereas proxyphylline suspensions had a thixotropic shear thinning behavior. These rheological behaviors can be explained by the chemical composition and by the ratio of the two Gelucires used. Extended release of proxyphylline was obtained with all these mixtures. Drug release increased with Gelucire mixture HLB owing to higher erosion. A viscosity-release relationship was found and allowed, with these two Gelucires of extreme HLB and viscosities, to define the formulations which will give an optimal drug release, by the determination of their suspension viscosity. Modeling of dissolution kinetics has generally shown the predominance of surface erosion of the plugs relative to drug diffusion inside the matrix. This was confirmed by the better linearization of percentage released, according to Hixson-Crowell as compared with Higuchi.

Fyn membrane localization is necessary to induce the constitutive tyrosine phosphorylation of Sam68 in the nucleus of T lymphocytes

A close relationship between Sam68, a tyrosine and proline-rich RNA-binding protein, and Src protein tyrosine kinases (PTK) has already been established, also in T lymphocytes. A constitutive phosphorylation of the molecule has also been documented in various transformed T cells, which probably reflects an increased expression of PTK of the Src family. Using the hybridoma T cell line, T8.1, or Jurkat T cells, we investigated the respective contribution of the two Src kinases Fyn and Lck, expressed in T cells, in this phenomenon. By overexpressing the two proteins, we show that the constitutive phosphorylation of Sam68 in vivo directly correlates with cellular Fyn levels, but not with Lck expression, despite the capacity of the PTK to strongly phosphorylate the molecule in vitro. Overexpressed Fyn is mainly localized at the cell membrane. We find that Sam68 phosphorylation, including in the nuclear fraction in which the molecule is predominantly expressed, is lost with a delocalized Fyn mutant deleted of its N-terminal membrane-anchoring domain. Finally, we demonstrate, using a construct encoding a Sam68 molecule without its nuclear localization signal, that nuclear expression of Sam68 is not required for phosphorylation. We conclude that the constitutive phosphorylation of Sam68 in T cells is a Fyn-dependent process occurring in a cell-membrane compartment from which phospho-Sam68 molecules can thereafter accumulate into the nucleus.

Rheology of polyol behenates and drug release from matrix monolithic capsules

Three polyol behenates with similar melting points (MP) and different hydrophilic-lipophilic balances (HLB) were studied (MP/HLB: 70/02, 63/05 and 57/13). After melting at MP+30 degrees C, the rheological behaviour of behenates was determined by adjustment of the rheograms to the Ostwald power-law and by statistical assessment of the flow index. Behenates showed slight shear thickening. This shear thickening increased when HLB of behenates decreased. This behaviour accounted for a reorganization of the particles under the shear, which became easier when the proportion of the polyethylene glycol chains in the wax decreased. Proxyphylline was used to prepare suspensions at a concentration of 25% in the melted behenates, and to manufacture monolithic capsules by cooling. The suspensions had a shear-thinning behaviour with or without thixotropy. Colloidal particles and aggregates formed in these suspensions directly influenced the rheological properties, as observation of solidified suspensions by scanning electron microscopy confirmed. Extended release of proxyphylline was obtained with the three waxes. Behenates 63/05 and 70/02 gave inert matrices and released drug very slowly. Hydrodispersible behenate 57/13 swelled and made up a kind of hydrophilic matrix that released proxyphylline more quickly, due to slight erosion. In the three cases, the release mechanism was basically diffusional in nature.

Extrusion-spheronization manufacture of Gelucire matrix beads

Theophylline extended-release spheres were prepared by extrusion-spheronization of matrix granulations previously obtained by incorporation of the drug in melted Gelucire 50/02 or Gelucire 55/18. Hydrophobic Gelucire 50/02 behaved as an inert matrix and released theophylline very slowly compared with hydrodispersible Gelucire 55/18, which acted as a hydrophilic matrix. Extrusion-spheronization was more easily accomplished with Gelucire 50/02. The use of ethanol as a wetting fluid increased the rate of drug release noticeably with Gelucire 50/02 and less so with Gelucire 55/18. The use of castor oil, in conjunction with ethanol to slow down the solvent evaporation, improved extrusion and spheronization. Castor oil decreased the drug release rate with Gelucire 50/02 and increased it with Gelucire 55/18. These phenomena were explained by the different solubilities of theophylline, Gelucire 50/02, and Gelucire 55/18 in ethanol and castor oil. When microcrystalline cellulose (Avicel CL 611) was used in the granulation matrix, extrusion was improved. The best formulation was obtained with Gelucire 55/18 and Avicel CL 611 and was wetted by a mixture of ethanol and castor oil. Regardless of the formulation, the mechanism of theophylline release appeared to be via Fickian diffusion.

Effect of formulation on the rheology of theophylline compound suspensions in Gelucires

The theophylline derivatives, etofylline, diprophylline and proxyphylline, which exhibit increasing aqueous solubility, were used to prepare suspensions in seven saturated polyglycolyzed glycerides (Gelucires) characterized by their rising hydrophilic-lipophilic balance (HLB). Drug concentration was set at 25% w/w and the production temperature was set at the Gelucire melting point plus 30 degrees C in order to obtain suitable suspensions. Various formulation factors were studied. Ostwald flow indices revealed that the suspensions had a thixotropic shear-thinning behaviour and a relative viscosity which increased as drug aqueous solubility rose and Gelucire HLB decreased. These rheological properties could be explained by the chemical composition of Gelucires and drugs used. A microstructure was proposed for the liquid suspension such that colloidal particles and aggregates formed in these suspensions directly influenced the observed rheological properties. Observation of solidified suspensions by scanning electron microscopy confirmed this hypothesis. Moreover, a correlation between the relative viscosity of drug suspensions on the one hand and drug concentration, drug solubility and Gelucire HLB on the other allowed for the calculation of the required concentration of each theophylline derivative in each Gelucire to obtain a given viscosity.

Rheological behaviour of saturated polyglycolysed glycerides

Seven saturated polyglycolysed glycerides (Gelucires) of melting points varying from 42 to 53 degrees C and hydrophilic-lipophilic balance values from 2 to 14 were selected. Their rheological behaviour was determined by adjustment of the flow curves to the Ostwald power-law and by statistical assessment of the flow index. The flow of Gelucires was slightly shear thickening. This shear thickening rose when the temperature and the lipophilic specificity of the Gelucire increased. This behaviour accounted for a reorganization of the particles under the shear which became easier when the temperature increased and when the degree of condensation of the polyethylene glycol chains decreased with lipophilicity of the Gelucires.

[Osteocalcin in chronic alcoholism]

In order to investigate the mechanism by which the inorganic content of the bone is reduced in chronic alcoholism, the authors assayed osteocalcin in 60 chronic alcoholics. The level was significantly lower than in control subjects. There was no significant difference between levels in cirrhotics and in non-cirrhotic alcoholics. There was a negative correlation between osteocalcin and gamma GT levels. There was no correlation between osteocalcin and blood calcium, blood phosphorus, ALAT, ASAT, alkaline phosphatase, 5'-nucleotidase, albumin or bilirubin levels, or with the prothrombin time. These results suggest a direct impact of alcohol on the osteoblast.

A skin suction blister model in hairless rats: application to the study of anti-inflammatory and immunomodulatory drugs

A suction blister model was developed in the hairless rat, in order to study the effects of various agents on the migration of polymorphonuclear leukocytes (PMN). A standardized abrasion, a suction blister, was formed by applying negative pressure to the skin and then separating the epidermis from the dermis. A migration chamber containing serum as the chemoattractant was placed over the wound. After 6 h of migration, the cells in the chamber were harvested, counted and identified. We evaluated PMN migration after treating the animals with active compounds: niflumic acid, and anti-inflammatory drug, and RU 41740, an immunomodulator. This in vivo model provided reproducible data and could be used to study further the functional properties of PMN. In addition, because this assay can also be used in man, a drug found to be effective in the animal system could then be tested for its activity in man.

[Prolongation of theophylline derivative release with cellulose acetate based tablets]

Sustained-release tablets were prepared with three theophylline compounds of increasing solubility: theophylline, dyphylline and proxyphylline. Cellulose acetate was used as the matrix polymer. Two formulation parameters were studied: incorporated theophylline dose and percentage of polymer constituting the matrix. Drug release was enhanced as these parameter values rose. A mixed mineral and plastic matrix was formed by the two insoluble excipients, i.e. cellulose acetate and dibasic calcium phosphate for direct compression. Drug release could be optimized either by 2(2) factorial analysis or by multiple linear regression. Drug solubility was found to have an especially important influence on the release and did not allow sustained-release tablets to be obtained when it was too great. In the case of dyphylline and proxyphylline, only the additional application of a barrier-coating over the surface of the matrix tablets enabled prevention of their premature erosion and the massive release of drugs.

Studies on the human chromosome 3 centromere with a newly cloned alphoid DNA probe

Starting from a chromosome-specific DNA library, we have isolated a human chromosome-specific satellite DNA sequence. This sequence of 635 base pairs (bp) consists of 3.7 alpha DNA monomers of 170-171 bp. Under high stringency it hybridizes to the centromere of chromosome 3 in a region composed of 2,750 bp tandem repeats characterized by the regular spacing of Hind III and TaqI restriction enzyme recognition sites. It has diverged and undergone amplification after the human speciation. The amplification allows an easy monitoring of the chromosome 3 centromere by in situ hybridization with a nonradioactive probe.

Dissolution of a soluble drug substance from vinyl polymer matrices

It was shown that vinyl polymers form good bases for in vitro sustained-release matrices, and that the character of the release curves is basically in line with their pH-solubility profiles. For a flow cell, the release curves may be approximated by the equation: In (m/m0) = - K(t -ti), where m is the amount not dissolved, m0 is the initial drug content, K is a dissolution constant, t is time, and ti is a lag time. Furthermore, it was shown that K is a function of tablet hardness (H) and polymer content (Q, percent). This functionality is well represented by the equation: In K = alpha H + gamma ln Q + epsilon, where alpha, gamma, and epsilon are polymer-dependent parameters. Matrix erosion is represented by an exponential decay: (p/p0) = exp(-Dt + a), where p is the amount not eroded, p0 is the initial weight, D is an erosion constant, and a is a soluble polymer-dependent parameter. In the case of these soluble polymers, K is not solely a function of D.

In vitro immunological activities of the polysaccharide fraction from Haemophilus influenzae type a endotoxin

Mild hydrolysis of Haemophilus influenzae type a lipopolysaccharide by ion exchangers in the presence of chloroform, to remove the lipid moiety, yielded a nontoxic and immunogenic polysaccharide fraction. This polysaccharide selectively triggered murine B lymphocytes in vitro: (i) it induced enhancement of thymidine incorporation and stimulated antibody secretion in cultures of normal and nude mouse spleen cells; (ii) it did not stimulate splenic T lymphocytes; (iii) the activation of B lymphocytes was not absolutely dependent on the presence of macrophages. Sepharose 4B gel filtration showed that this polysaccharide consisted at least of two fractions: PS I (molecular weight [MW] 10(6)) and PS II (MW 10(4)). Only PS I was found to act as a polyclonal B cell activator. EDTA treatment dissociated the polysaccharide into PS III (MW 10(6)) and PS IV (MW 10(4)), which was not reassembled after the addition of 0.02 M CaCl2. Both fractions PS III and PS IV were unable to stimulate B lymphocytes. The immunological active fraction of H. influenzae polysaccharide is PS I. This fraction consists of a high-molecular-weight group (10(6)) and an association of 10(4)-MW aggregated units.

Characteristics of a lipid preparation (lipid A) from Haemophilus influenzae type a lipopolysaccharide

Mild hydrolysis of Haemophilus influenzae type a lipopolysaccharide by ion exchangers yielded a lipid A extracted by chloroform. It contained phosphorus, glucosamine, and fatty acids. Myristic, palmitic, 3-hydroxymyristic, and oleic acids and two other unidentified long-chain fatty acids were found. The free lipid A was not toxic for mice at doses of up to 50 mg/kg and did not provoke a Shwartzman reaction. The Limulus test activity was positive up to 10(-12) g/ml, but the pyrogenicity in rabbits was lower than with the original lipopolysaccharide. However, the lipid A did induced a mitogenic response and polyclonal B-cell activation in mouse spleen cell cultures. Complexing lipid A with bovine serum albumin gave a nontoxic preparation which lost these immunological activities. Immunochemical studies showed that the major reactive determinants of this lipid-protein complex were altered after such a linkage. Consequently, the nontoxic and mitogenic lipid A isolated from H. influenzae type a did not exhibit all of the classical activities of lipid A preparations.

Comparative study of biological activities and mitogenic effect of extracts from Haemophilus influenzae type a

Two preparations designated as PWE and NCE were obtained from H, influenzae type a by treatment with either phenol water or hypertonic NaCl citrate respectively. The protein content of NCE was three fold higher than for PWE. Electroimmunodiffusion against H. influenzae antiserum disclosed an immunological relationship between NCE and PWE. The toxicity for mice was lower for both antigenic extracts (LD50 PWE: 47 +/- 7 mg/kg; LD50 NCE: 943 +/- 5 mg/kg) than for E. coli LPS. Limulus assay showed that both H. influenzae extracts had a weaker potency (100 to 1000 times less) than E. coli LPS. Sanarelli and Shwartzman reactions failed for PWE and NCE. The blast transformation of DBA/2 and nude mouse spleen cells were strikingly different for the three preparations: PWE, NCE, and E. coli LPS. Neither extract from H. influenzae cells showed the biological properties of a classical endotoxin. We suggest that they are endotoxin-like substances.

Preparation of a nontoxic and immunogenic polysaccharide fraction from a Haemophilus influenzae phenol-water extract

A phenol-water extract from Haemophilus influenzae type a was hydrolyzed to decrease the toxicity without affecting the antigenicity of the preparation. We used partial hydrolysis for 15 h with ion exchangers in the presence of chloroform. The lipid fraction was collected into the organic solvent. The preparation obtained from the aqueous solution was designated the polysaccharide fraction. Rhamnose, glucose, galactose, mannose, and glucosamine were the major components of the polysaccharide fraction, and their molar ratios were determined by gas-liquid chromatography; 2.5% myristic acid was also found in the polysaccharide fraction. The mild hydrolysis of the polysaccharide fraction for 15 h caused a marked reduction in toxicity (50% lethal dose, 183 +/- 9 microgram/kg) and pyrogenicity. The generalized Sanarelli reaction was negative. The local Shwartzman phenomenon was not observed if chloroform and Dowex were exchanged three times during hydrolysis. Most of the antigenic components remained active after the hydrolytic process. The polysaccharide fraction could also induce the formation of circulating antibodies in rabbits and also increase the phagocytic process against H. influenzae from month 2 to 6.

[Studies on an extract from Haemophilus influenzae type a. II.--Phagocytic capacity of sera obtained from rabbits immunized by this bacterial extract (author's transl)]

Opsonins may protect against infections. In this study, the different parameters of opsonization assay are strictly standardized. Results are expressed as percentage of opsonization. 0% and 100% opsonization must be established. The experiment without immunserum is used as the 0% opsonization. To determine the 100% opsonization an excess of reducing capacity is required. This is provided by crushed leukocytes. Rabbits are immunised by bacterial extract from Haemophilus influenzae type a. The hemagglutinins are detected in sera earlier (D + 30) and longer than the opsonic activity. Phagocytosis increases from the second month following the immunization. Percentage of opsonization is maintained at about 50% up to the sixth month. Alternatively, the percentage of phagocytosis is decreasing when heterologous bacteria are used. The serum thermolabile factors are necessary for the response. The phagocytic capacity is not modified whether leukocytes are obtained from immunized rabbits or not.

[Studies on an extract from Haemophilus influenzae type a. I.--Antigenic and immunogenic studies (author's transl)]

Haemophilus influenzae is the bacteria most commonly found in chronical bronchitis not treated by antibiotic therapy. Experimental studies have suggested that the destruction of the ciliated respiratory epithelium is in conjunction with the toxic product of the cell-wall of this bacteria. Endotoxin is extracted by phenol-water procedure. Toxicity is reduced by mild hydrolysis. Antigenicity of the preparation is controlled by gel diffusion in a parallel sides-tank diffusion and electroimmunodiffusion. These methods show that common antigenicity is not affected by hydrolysis. After immunisation by that preparation, circulating antibodies are detected by passive hemagglutination and immuno-precipitation. The immunized rabbits have agglutinin titer of 1 : 256th. Antigenicity of this bacterial extract is preserved and the preparation is still immunogenic.

Chemical composition and biological activities of a phenol-water extract from Haemophilus influenzae type a

Ribonucleic acid was removed from a phenol-water extract of Haemophilus influenzae type a by streptomycin sulfate. This preparation was called purified preparation or PP. It contained neutral sugars (glucose, galactose, mannose, pentose), glucosamine, amino acids, and fatty acids. Heptose and 2-keto-3-deoxyoctonic acid were not present. The biological properties and immunogenicity were compared with the activities of lipopolysaccharide of Escherichia coli or Salmonella typhimurium. Higher doses were necessary to obtain lethality in mice and Sanarelli and Shwartzman reactions with our preparations than were necessary with lipopolysaccharide. The Limulus test and pyrogen assay in rabbits gave the same results with purified preparation and lipopolysaccharide, but pyrogenicity of purified preparation was not destroyed by NaOH treatment. Purified preparation was not as immunogenic at low doeses for rabbits as lipopolysaccharide. The results were different from those obtained with lipopolysaccharide but similar to those known from peptidoglycan studies. The contamination of purified preparation with peptidoglycan was negligible and cannot explain the biological activities of purified preparation. We suggest that the phenol-water extract from H. influenzae is not a classical endotoxin, but rather an endotoxin-like substance.