Intestinal mast cell response and mucosal defence against Strongyloides venezuelensis in interleukin-3-hyporesponsive mice

Mineralization in the pulp is a common finding in permanent as well as primary teeth and is associated with caries, aging, traumatic injuries and systemic conditions. This article describes an unusual pattern of pulpal calcification. A tube-like calcified structure formed in the dental pulp of primary incisors following mild traumatic injuries. It was studied by clinical, radiographic and histologic evaluation and by scanning electron microscopy. The tube-like structure was found to extend along the entire length of the pulp canal. Generally it was separated from the root dentin by normal pulp tissue, but was connected to the dentin in some sites. It had the histologic appearance of osteodentin with cell inclusions in a ring-like formation that was incomplete in places. The scanning electron microscope study showed rough inner and outer surfaces of a tube-like structure with openings that seemed to be dentinal tubules.     

Influence of rat strain on larval production by the parasitic nematode Strongyloides ratti

The course of infection with Strongyloides ratti in a range of rat strains was assessed by monitoring the production of larvae. To our knowledge, this is the first such study of S. ratti using its natural host Rattus norvegicus. Host strain influenced the pattern of larval production. The results were qualitatively the same for 2 S. ratti lines of North American and Japanese origin.     

Cryo-microtome sections of coproculture larvae of Strongyloides stercoralis and Strongyloides ratti as antigen sources for the immunodiagnosis of human strongyloidiasis

Cryo-microtome sections of larvae of Strongyloides stercoralis and S. ratti respectively obtained from human and rat feces cultures, were used as antigens. Fluoresceinate conjugates against human IgG were employed at the ideal titer of 10 for S. stercoralis and 100 for S. ratti. The sensitivity of the indirect immunofluorescence reaction (IIF) was 94.4% and 92.5% and the specificity 94.2% and 97.1% for the two specific larval antigens, respectively. Sera from 123 persons (54 from carriers of S. stercoralis infections and 69 from controls) were submitted to the reaction. The titers of different sera varied from 20 to 2560. There was a significant linear correlation (r = 0.85 p < or = 0.001) between the antibodies from the two species of larval antigens. We conclude that both antigens may be used in the IIF reaction for the diagnosis of human strongyloidiasis. Due to the feasibility of safe and low-cost mass production of S. ratti larvae in the laboratory with a considerable economy of conjugate, their utilization in the serum diagnosis of human strongyloidiasis is recommended.     

The population genetic structure of the facultatively sexual parasitic nematode Strongyloides ratti in wild rats

We have investigated the population genetic structure of the parasitic nematode Strongyloides ratti in wild rats. In the UK, S. ratti reproduces predominantly by mitotic parthenogenesis, with sexual forms present at a rate of less than 1%. S. ratti was found to be a prevalent parasite and substantial genetic diversity was detected. Most rats were infected with a genotypic mixture of parasites. A hierarchical analysis of the genetic variation found in S. ratti sampled across Britain and Germany showed that 73.3% was explained by variation between parasites within individual hosts and 25.3% by variation between rats within sample sites. Only a small proportion (1.4%) of the total genetic variation was attributable to genetic subdivision between sample sites, suggesting that there is substantial gene flow between these sites. Most parasites sampled were found to exist in Hardy-Weinberg equilibrium and this population genetic structure is discussed in view of the virtual absence of sexual reproduction.     

In vitro modulatory effects of interleukin-3 on macrophage activation induced by interleukin-2

BACKGROUND: The concomitant activation of macrophage-mediated immunosuppressive events might represent one of the most important biologic factors responsible for the decreased efficacy of cancer immunotherapies, including that of interleukin (IL)-2. In previous studies, the authors observed that the increase in the soluble IL-2 receptor (SIL-2R) and neopterin levels was related to the generation of macrophage-mediated immunosuppression and associated with a reduced clinical efficacy during IL-2 cancer immunotherapy. Because both cytokines and neurohormones may influence the macrophage system, the current study was done to evaluate the effects of IL-3 and of the pineal hormone melatonin (MLT) on monocyte response to IL-2 administration. METHODS: Peripheral blood monocytes were incubated with different concentrations of IL-2, IL-3, and MLT, either alone or in association. RESULTS: SIL-2R, neopterin, and tumor necrosis factor-alpha mean concentrations in the medium significantly increased during incubation with IL-2 at a concentration of 100 Cetus units/ml. IL-3 alone, at a dose of 10 ng/ml, also stimulated tumor necrosis factor release; no effect was found on SIL-2R and neopterin. The IL-2-induced neopterin rise was blocked by a concomitant incubation with IL-3 at a dose of 10 ng/ml. Finally, the concomitant incubation with IL-3 and MLT further inhibited neopterin release and significantly decreased IL-2-induced SIL-2R secretion. CONCLUSIONS: These results suggest that IL-3 alone or in association with MLT may modulate macrophage functions during cancer immunotherapy with IL-2 and decrease the IL-2-induced macrophage activation.     

Modulation of peripheral leukocyte counts and bone marrow function in mice by oral administration of interleukin-2

Interferons alpha, beta, and gamma have been shown to exert systemic effects following their oral administration to mice. It was of importance to determine whether oral administration of another biologic response modifier, interleukin-2 (IL-2), could also exert systemic effects in mice. Two systemic effects, peripheral WBC suppression and bone marrow suppression, were evaluated. Oral administration of IL-2 was found to suppress the peripheral WBC count in a dose-dependent manner. Oral administration of IL-2 was also found to suppress the bone marrow proliferative activity. The levels of suppression of both peripheral WBC and myelopoietic progenitor cell numbers observed with orally administered IL-2 were comparable to those seen with subcutaneously administered IL-2. The results demonstrate that orally administered IL-2 can exert systemic effects. Further, the results raise the possibility that oral administration of IL-2 may have therapeutic potential.     

Serum rheumatoid factor induced by intraperitoneal administration of periodontopathic bacterial lipopolysaccharide in mice

Serum rheumatoid factor (RF) level and peritoneal and splenic CD5+B (B-1) cells in mice were examined after intraperitoneal administration of purified lipopoly-saccharides (LPS) from oral periodontopathic bacteria; Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum and Capnocytophaga ochracea. F. nucleatum and C. ochracea LPS induced higher levels of serum IgM- and IgG-RF, while P. gingivalis LPS showed the least induction. In addition, wet weights of spleen and serum IgM and IgG concentration were markedly increased in F. nucleatum LPS injected group. On the other hand, the proportion of CD5+ B cells to lymphocytes in the peritoneal cavity and spleen did not increase. The reason for this was not clear but conventional B cells (CD5- B cells) might increase more rapidly with splenic enlargement than CD5+ B cells. These results suggested that RF induced by bacterial LPS may modulate immune responses against bacteria and plays an important role for defence and destruction of periodontal tissue.     

Synergistic protection against cartilage destruction by low dose prednisolone and interleukin-10 in established murine collagen arthritis

BACKGROUND: For simplification of blood cell transplantation, an automated apheresis system that exploits a dual-stage channel device for mononuclear cell (MNC) collection (AutoPBSC, designed for the COBE Spectra) was studied. STUDY DESIGN AND METHODS: The automated default software (AutoPBSC-Default) and three software modifications of the harvest frequency during leukapheresis, referred to as AutoPBSC-1.25, AutoPBSC-1.75, and AutoPBSC-2.75, were evaluated in comparison with the semiautomated Version 4.7 (V4.7) apheresis system in 119 leukapheresis procedures performed in 90 cancer patients treated with chemotherapy plus granulocyte-colony-stimulating factor. CD34+ cell and platelet collection efficiency (CE); volume and cell composition of the leukapheresis components; and patient platelet and red cell (RBC) loss during leukapheresis were measured. RESULTS: The majority of collection measures evaluated with the AutoPBSC compared favorably to those obtained with the V4.7. CD34+ cell CE increased from 55 percent with V4.7 to 68 percent with the AutoPBSC-Default (p = 0.05). The AutoPBSC provided lower platelet contamination in the collected component (1.18 x 10(11) vs. 2.26 x 10(11) with the V4.7; p<0.001). The volume of the AutoPBSC-Default component was significantly lower (67 vs. 180 mL with the V4.7; p<0.001). The MNC purity of the AutoPBSC component was greater (52 vs. 28% with the V4.7; p<0.001), and the RBC contamination lower (AutoPBSC, 0.53 x 10(11) vs. 1.04 x 10(11) with the V4.7; p<0.001). Modifications of the AutoPBSC to increase the harvest frequency by 1.25-, 1.75-, and 2.75-fold resulted in increased CD34+ cell CE (77%, 75%, and 83%, respectively; p<0.001 in all cases), but also in reduced numbers of circulating platelets, higher platelet contamination of the component, and lower MNC purity than were seen with the AutoPBSC-Default. CONCLUSION:The AutoPBSC offers the following advantages over the V4.7 system: a) better CE of CD34+ cells; b) reduced collection of platelets; c) reduced contamination of the leukapheresis component with granulocytes, platelets, and RBCs; d) reduced component volume; and e) automation.     

Mechanism and specificity of immunoprotection induced by mycobacterial proteins against experimental tuberculosis in mice

Mechanism of immunoprotection and specificity of two highly immunoprotective mycobacterial proteins, viz. 71 and 30 kDa were investigated. The adoptive transfer studies indicated that immunoprotection was mainly mediated by cooperative effect of CD4+ and CD8+ (66.7-73.3% on the basis of percent survival) which was further enhanced marginally by supplementation of B cells, natural killer cells, dendritic cells, macrophages and other immune cells. The specificity studies indicated that both the proteins did not cross react with the unrelated intracellular pathogens i.e. Aspergillus fumigatus, Salmonella typhi and Leishmania donovani as seen by T cell proliferation assay. The protection imparted by these mycobacterial proteins was also specific as the 71 and 30 kDa primed mice did not exhibit any cross protection against sublethal challenge of S typhi. The results indicate 71 and 30 kDa mycobacterial proteins to contain T cell specific epitopes responsible for specific immunoprotection, thus indicating their potential role as antituberculous vaccine candidates.     

Failure of protection induced by a Brazilian vaccine against Brazilian wild rabies viruses

This report shows that the SMB vaccine currently used in Brazil for human immunisation provides different degrees of protection in mice, depending on the rabies virus strain used as challenge. Using the NIH and Habel potency tests to evaluate the protective activity of rabies vaccine, we observed that vaccinated mice showed a higher resistance to a challenge with a fixed rabies virus (CVS-Challenge Virus Strain). The vaccine potency using the Habel or NIH tests was respectively > 6.4 (log 10) and 1.0 (Relative Potency-RP) when the fixed rabies virus was used for challenge, and from 2.9 to 4.3 (log 10) or 0.13 to 0.8 (RP) when different wild rabies viruses were used for challenge. The presence of virus neutralising antibodies (VNA) could not explain the differences of susceptibility after vaccination, since sera of vaccinated animals had similar VNA levels against both fixed and wild strains before virus challenge (respectively, 5.6 +/- 0.24 and 5.0 +/- 0.25 IU/ml of VNA against the fixed rabies virus and the 566-M strain of wild rabies virus in sera of mice vaccinated with 0.2 units of vaccine). Only cell-mediated immunity parameters correlated with the protection induced by vaccination. The IFN gamma titers found in sera and brain tissues of animals challenged with CVS strain were higher (from 36.7 +/- 5.7 to 293.3 +/- 46.2 IU/ml) than those found in mice challenged with 566-M virus strain (from 16.7 +/- 5.8 to 36.7 +/- 5.8). The proliferation index of spleen cells obtained with CVS stimulation reached a maximal value of 15.1 +/- 0.7 while spleen cells from vaccinated mice stimulated with 566-M virus failed to proliferate. The implications of these data in human protection by vaccination are discussed.     

Oral administration of L-arginine potentiates allergen-induced airway inflammation and expression of interleukin-5 in mice

The role of nitric oxide in the airway hyperresponsiveness and inflammation of bronchial asthma has not yet been established. However, L-arginine, the substrate for nitric oxide synthases, reportedly alleviates airway hyperresponsiveness caused by parainfluenza virus and reduces granulocytic inflammation induced by ischemia-reperfusion. We investigated the effects of L-arginine on a murine model of allergic asthma that included airway hyperresponsiveness, eosinophilic inflammation and expression of interleukin (IL)-5 in the lung. The mice received drinking water with or without L-arginine for 9 weeks. Histologic evaluation and cellular profiles in bronchoalveolar lavage fluid showed that p.o. administration of L-arginine (72 micromol/kg/day) significantly enhanced eosinophilic airway inflammation and goblet cell proliferation that were associated with intratracheal instillation of ovalbumin. L-Arginine also increased protein levels of IL-5 and IL-2 in supernatants from the lung exposed to ovalbumin. The number of eosinophils in bronchoalveolar lavage fluid correlated significantly with the expression of IL-5. L-Arginine did not reverse ovalbumin-associated airway hyperresponsiveness to inhaled ACh. These results suggest that p.o. administration of L-arginine aggravates allergen-induced eosinophilic airway inflammation via expression of IL-5, and in this model it does not show therapeutic efficacy against airway hyperresponsiveness associated with allergen exposure. Oral administration of L-arginine, the precursor of nitric oxide, may not be an effective intervention in allergic asthma.     

Involvement of interleukin-1 in the development of ulcerative colitis induced by dextran sulfate sodium in mice

Dextran sulfate sodium (DSS)-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, the effects of anti-murine interleukin 1beta (IL-1beta) antibodies (anti-muIL-1beta) and recombinant murine IL-1 receptor type I (rmuIL-1R) on the development of colitis were examined to determine whether IL-1 plays a role in colitis. Furthermore, RT-PCR amplification was used to examine for the presence of mRNAs for IL-1alpha and IL-1beta in the large intestine. In mice with colitis induced by DSS, administration of anti-muIL-1beta (5 mg/kg, once/week, i.p.) significantly suppressed body weight loss and shortening of the large intestine. Administration of rmuIL-1R (0.2 mg/kg or 1.0 mg/kg, once/day, i.v.) significantly suppressed shortening of the large intestine. Expression of mRNAs for IL-1alpha and IL-1beta was observed in the large intestine of mice which received distilled water containing 3% DSS for 5 days. The expression tended to increase in mice which received DSS for 11 days. In contrast, mRNA expression was not observed in mice which received distilled water without DSS. These results clearly demonstrate that IL-1 is involved in the development of DSS-induced colitis in mice and suggest that downregulation of IL-1 might be useful for the treatment of patients with ulcerative colitis.     

Intestinal fluid accumulation induced by oral challenge with Vibrio cholerae or cholera toxin in infant mice

The diarrheal response of orally inoculated infant mice to viable Vibrio cholerae and purified cholera toxin was quantitated by means of a fluid accumulation (FA) ratio. The FA ratio is defined as the gut weight/remaining body weight. FA ratios were determined in relation to time of exposure and dose. Onset of fluid accumulation with viable cells of strains CA401 and 569B occurred 8 h postinoculation and reached a near maximum of 16 h. A dose of 4 x 10(6) colony-forming units of strain CA401 was required for a positive response 16 to 18 h postinoculation. Several other classical cholera strains demonstrated a similar dose-related response. Strain 569B, however, required a 100-fold higher dose to give a positive response. Several mutant cholera strains were decreased virulence in other model systems elicited FA ratios decreased from wild-type values. Onset of fluid accumulation which cholera toxin occurred 6 to 8 h postinoculation and reached a maximum by 10 h. A dose of 0.5 microng was required for a positive response 10 to 12 h postinoculation. The positive response to toxin could be inhibited by preincubation with specific antitoxin.     

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

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

Protective cellular immunity against influenza virus induced by plasmid inoculation of newborn mice

The mercury-binding capacity of seleno-DL-methionine and selenium dioxide was assessed in male Wistar rats. Mercury was supplied as fish loaves made of northern pike or rainbow trout. We used a selenium concentration of 3.4 mg/kg fish, about sixfold compared to the equivalent quantity of mercury. Seleno-DL-methionine had a tendency to increase both methyl mercury and total mercury in blood, although it also seemed to reduce the proportion of methyl mercury of total mercury. Selenium dioxide lowered mercury levels by 24-29% both in the blood and in the liver of rats that were fed with northern pike.     

Timing of recombinant human granulocyte colony-stimulating factor administration on neutropenia induced by cyclophosphamide in normal mice

Chagas' disease is an infectious disease that affects millions of people in Latin America and is increasingly seen outside endemic areas. A substantial number of patients develop gastrointestinal disorders secondary to lesions of the enteric nervous system. The purpose of this article is to review the current knowledge about gastrointestinal manifestations of Chagas' disease, including disorders other than the well-known gross dilations of esophagus and colon.     

Acute induction of interleukin-6 and biphasic changes of serum complement C3 by carrageenan in mice

Oat cell carcinoma is rarely diagnosed in the head and neck and can be primary or secondary. Primary tumors arise from amine precursor uptake and decarboxylation cells which are found throughout the head and neck. Secondary deposits metastasize most commonly from the lungs. We report a 64-year-old woman with a known pancreatic oat cell carcinoma who came to the ENT Department with dysphagia. On examination, a lesion was seen at the base of the tongue and was histologically an oat cell carcinoma. No treatment was administered and the patient died one month after discharge. This report highlights the difficulty in determining the primary site when a rare tumor metastasizes to the head and neck and no autopsy findings are obtained. To our knowledge, oat cell carcinoma of the tongue has not been previously reported.     

Differential antagonism by MK-801 against antinociception induced by opioid receptor agonists administered supraspinally in mice

Various doses of MK-801 ((+/-)-5-methyl-10,11-dihydro-5H-dibenzo(a,d) cyclohepten-5, 10-imine maleate), a non-competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist (0.001-1 microgram) injected intracerebroventricularly (i.c.v.) alone did not show any antinociceptive effect. MK-801 (0.001-1 microgram i.c.v.) dose dependently attenuated the inhibition of the tail-flick and hot plate responses induced by i.c.v. administered morphine (1 microgram), [D-Pen2, D-Pen5]enkephalin (DPDPE; 10 micrograms), and U50,488H (trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeoce tamide ) 60 micrograms). However, the inhibition of the tail-flick and hot plate responses induced by i.c.v. administered beta-endorphin (1 microgram) was not changed by i.c.v. administered MK-801. Our results indicate that, at the supraspinal level, NMDA receptors are involved in the production of antinociception induced by supraspinally administered morphine, DPDPE, and U50,488H but not beta-endorphin.     

Protective effect of melatonin against hippocampal DNA damage induced by intraperitoneal administration of kainate to rats

The pineal hormone melatonin protects neurons in vitro from excitotoxicity mediated by kainate-sensitive glutamate receptors and from oxidative stress-induced DNA damage and apoptosis. Intraperitoneal injection on kainate into experimental animals triggers DNA damage in several brain areas, including the hippocampus. It is not clear whether melatonin is neuroprotective in vivo. In this study, we tested the in vivo efficacy of melatonin in preventing kainate-induced DNA damage in the hippocampus of adult male Wistar rats. Melatonin and kainate were injected i.p. Rats were killed six to 72 h later and their hippocampi were examined for evidence of DNA damage (in situ dUTP-end-labeling, i.e. TUNEL staining) and for cell viability (Nissl staining). Quantitative assay was performed using computerized image analysis. At 48 and 72 h after kainate we found TUNEL-positive cells in the CA1 region of the hippocampus; in the adjacent sections that were Nissl-stained, we found evidence of cell loss. Both the number of TUNEL-positive cells and the loss of Nissl staining were reduced by i.p. administration of melatonin (4 x 2.5 mg/kg; i.e. 20 min before kainate, immediately after, and 1 and 2 h after the kainate). Our results suggest that melatonin might reduce the extent of cell damage associated with pathologies such as epilepsy that involve the activation of kainate-sensitive glutamate receptors.