Response Of Guinea Pigs Research Articles

Pulmonary surfactant and prostaglandin E2 in airway smooth muscle relaxation of human and male guinea pigs.

Pulmonary surfactant serves as a barrier to respiratory epithelium but can also regulate airway smooth muscle (ASM) tone. Surfactant (SF) relaxes contracted ASM, similar to β2-agonists, anticholinergics, nitric oxide, and prostanoids. The exact mechanism of surfactant relaxation and whether surfactant relaxes hyperresponsive ASM remains unknown. Based on previous research, relaxation requires an intact epithelium and prostanoid synthesis. We sought to examine the mechanisms by which surfactant causes ASM relaxation. Organ bath measurements of isometric tension of ASM of guinea pigs in response to exogenous surfactant revealed that surfactant reduces tension of healthy and hyperresponsive tracheal tissue. The relaxant effect of surfactant was reduced if prostanoid synthesis was inhibited and/or if prostaglandin E2-related EP2 receptors were antagonized. Atomic force microscopy revealed that human ASM cells stiffen during contraction and soften during relaxation. Surfactant softened ASM cells, similarly to the known bronchodilator prostaglandin E2 (PGE2) and the cell softening was abolished when EP4 receptors for PGE2 were antagonized. Elevated levels of PGE2 were found in cultures of normal human bronchial epithelial cells exposed to pulmonary surfactant. We conclude that prostaglandin E2 and its EP2 and EP4 receptors are likely involved in the relaxant effect of pulmonary surfactant in airways.

Influence of <i>Yersinia pestis</i> with different plasmid composition on the erythrocyte membrane in the blood of guinea pigs

Introduction. Based on data on the role of blood erythrocytes in the development and implementation of the vaccine and infectious processes in plague, it was of interest to evaluate changes in erythrocyte surface architecture from the position of searching for informative criteria for the preclinical evaluation of anti-plague vaccines. Aim — using atomic force microscopy to characterize the state of the blood erythrocyte membrane of guinea pigs in response to subcutaneous administration of the vaccine strain Yersinia pestis EV NIIEG and its isogenic derivatives. Materials and methods. For immunization of animals strain Y. pestis EV NIIEG (pYT+, pYV+, pYP+) and its isogenic derivatives Y. pestis KM216 (pYT–, pYV–, pYP+), Y. pestis KM217 (pYT–, pYV+, pYP–), Y. pestis KM218 (pYT–, pYV–, pYP–) were used. Analysis of the erythrocyte membrane was carried out using a Solver P47-PRO scanning probe microscope (NT-MDT, Russia). Results. The most pronounced changes in the surface architectonics of the membrane of guinea pig erythrocytes were established during the first three days of the formation of the immune response to the Y. pestis EV strain NIIEG and its isogenic variant Y. pestis KM217, in the genome of which the pYV plasmid is preserved, administered at a dose of 5 × 108 CFU. A significant increase (p 0.05) in the proportion of transformed cell forms (43.67 ± 3.63% and 37.83 ± 7.03% versus 4.08 ± 0.86% in the control group), root mean square roughness (319 ± 8 nm and 312 ± 7 nm versus 70 ± 6 nm in the control group), Young's modulus (125.73 ± 4.48 kPa and 113.8 ± 5.41 kPa versus 53.03 ± 1.47 kPa in the control group). By the 21st day, the value of these indicators decreased by an average of 2.7, 2.0 and 1.5 times, respectively, indicating restoration of the erythrocyte membrane. Conclusion. The dependence of the changes in the erythrocyte membrane and the rate of their restoration on the plasmid composition of Y. pestis strains has been established. The data obtained contribute to the understanding of the processes of interaction of Y. pestis with the erythrocyte membrane and can be used as additional characteristics in the development of new criteria for preclinical evaluation of plague candidate vaccines.

Indirubin mediates adverse intestinal reactions in guinea pigs by downregulating the expression of AchE through AhR

ABSTRACT Indirubin is the main component of the traditional Chinese medicine Indigo naturalis (IN), a potent agonist of aryl hydrocarbon receptors (AhRs). In China, IN is used to treat psoriasis and ulcerative colitis, and indirubin is used for the treatment of chronic myelogenous leukaemia. However, IN and indirubin have adverse reactions, such as abdominal pain, diarrhoea, and intussusception, and their specific mechanism is unclear. The purpose of our research was to determine the specific mechanism underlying the adverse effects of IN and indirubin. By tracking the modifications in guinea pigs after the intragastric administration of indirubin for 28 days. The results demonstrate that indirubin could accelerate bowel movements and decrease intestinal acetylcholinesterase (AchE) expression. Experiments with NCM460 cells revealed that indirubin significantly reduced the expression of AchE, and the AchE levels were increased after the silencing of AhR and re-exposure to indirubin. This study showed that the inhibition of AchE expression by indirubin plays a key role in the occurrence of adverse reactions to indirubin and that the underlying mechanism is related to AhR-mediated AchE downregulation.

Development, preparation, and evaluation of a novel non-adjuvanted polyvalent dermatophytes vaccine

Ringworm is a worldwide distributed contagious disease infecting both man and animals that constitute an economic, zoonotic, and health problem concern all over the world. During the last decade, attention has been directed to vaccination as an ideal approach to the control of such diseases. In the present study, non-adjuvanted polyvalent vaccines were prepared from locally isolated hot and virulent dermatophyte species, namely Trichophyton verrucosum (T. verrucosum), Trichophyton mentagrophytes (T. mentagrophytes), and Microsporum canis (M. canis) were immunologically evaluated. The prepared vaccine evaluation was focused on the aspects of immunogenicity and protective efficacy using guinea pigs. Both in its living or inactivated forms, the vaccine-induced significant humoral and cell-mediated immune responses and achieve proper protection of guinea pigs against challenging infections with homologous and heterologous dermatophyte strains. On the other hand, investigations on dermatophyte exo-keratinases showed that it was better produced and more expressed in a mineral-based medium containing pure keratin (3 g/L) than in the same medium with human hair supplementation (2.6 g/L). The maximum dermatophyte productivity of exo-keratinases was found to be between 18 and 21 days post-incubation. Using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), two fractions with molecular weights of 40 kDa (fraction I) and 28 kDa (fraction II) have been identified in the culture filtrate of the three involved dermatophyte species. Both fractions demonstrated keratinolytic activity. The specific activity of the isolated keratinases (number of Keratinase units (KU)/mg protein) was stronger in fraction I, where it reached 18.75, 15.38, and 14 KU/mg protein as compared to 12.9, 8.74, and 12 KU/mg protein in fraction II of T. verrucosum, T. mentagrophytes, and M. canis, respectively. The dermatophyte exo-keratinases proved to be immunogenic as they stimulated high keratinase-specific antibody titers and induced strong delayed skin hypersensitivity reactions in vaccinated animals. Anti-keratinase-specific IgG was detected in sera of guinea pigs immunized with the inactivated or living polyvalent dermatophyte vaccines by a homemade enzyme-linked immunosorbent assay (ELISA) using dermatophyte exo-keratinases as coating antigen. The intradermal injection of dermatophyte exo-keratinases induced specific delayed skin reactions in guinea pigs immunized with the inactivated or the living polyvalent dermatophyte vaccines. The intradermal injection of dermatophyte exo-keratinases in the control non-sensitized guinea pigs was associated with itching, swelling, and bloody scar formation, however, no skin indurations were formed. The development of those post-exo-keratinases injection reactions in the control non-sensitized apparently healthy guinea pigs group, suggests an exo-keratinases possible role in the pathogenesis of dermatophytosis.

8-Oxo-2’-Deoxyguanosine, an Oxidatively Modified Guanine Nucleoside, Does Not Exhibit Any Skin Sensitizing Reactions in Guinea Pigs

8-Oxo-2’-Deoxyguanosine, an Oxidatively Modified Guanine Nucleoside, Does Not Exhibit Any Skin Sensitizing Reactions in Guinea Pigs

Topographic and widespread auditory modulation of the somatosensory cortex: potential for bimodal sound and body stimulation for pain treatment

Objective. There has been growing interest in understanding multisensory integration in the cortex through activation of multiple sensory and motor pathways to treat brain disorders, such as tinnitus or essential tremors. For tinnitus, previous studies show that combined sound and body stimulation can modulate the auditory pathway and lead to significant improvements in tinnitus symptoms. Considering that tinnitus is a type of chronic auditory pain, bimodal stimulation could potentially alter activity in the somatosensory pathway relevant for treating chronic pain. As an initial step towards that goal, we mapped and characterized neuromodulation effects in the somatosensory cortex (SC) in response to sound and/or electrical stimulation of the body. Approach. We first mapped the topographic organization of activity across the SC of ketamine-anesthetized guinea pigs through electrical stimulation of different body locations using subcutaneous needle electrodes or with broadband acoustic stimulation. We then characterized how neural activity in different parts of the SC could be facilitated or suppressed with bimodal stimulation. Main results. The topography in the SC of guinea pigs in response to electrical stimulation of the body aligns consistently to that shown in previous rodent studies. Interestingly, auditory broadband noise stimulation primarily excited SC areas that typically respond to stimulation of lower body locations. Although there was only a small subset of SC locations that were excited by acoustic stimulation alone, all SC recording sites could be altered (facilitated or suppressed) with bimodal stimulation. Furthermore, specific regions of the SC could be modulated by stimulating an appropriate body region combined with broadband noise. Significance. These findings show that bimodal stimulation can excite or modulate firing across a widespread yet targeted population of SC neurons. This approach may provide a non-invasive method for altering or disrupting abnormal firing patterns within certain parts of the SC for chronic pain treatment.

Alteration of EIF2 Signaling, Glycolysis, and Dopamine Secretion in Form-Deprived Myopia in Response to 1% Atropine Treatment: Evidence From Interactive iTRAQ-MS and SWATH-MS Proteomics Using a Guinea Pig Model.

Purpose: Atropine, a non-selective muscarinic antagonist, effectively slows down myopia progression in human adolescents and several animal models. However, the underlying molecular mechanism is unclear. The current study investigated retinal protein changes of form-deprived myopic (FDM) guinea pigs in response to topical administration of 1% atropine gel (10 g/L). Methods: At the first stage, the differentially expressed proteins were screened using fractionated isobaric tags for a relative and absolute quantification (iTRAQ) approach, coupled with nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) (n = 24, 48 eyes) using a sample pooling technique. At the second stage, retinal tissues from another cohort with the same treatment (n = 12, 24 eyes) with significant ocular changes were subjected to label-free sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics for orthogonal protein target confirmation. The localization of Alpha-synuclein was verified using immunohistochemistry and confocal imaging. Results: A total of 1,695 proteins (8,875 peptides) were identified with 479 regulated proteins (FC ≥ 1.5 or ≤0.67) found from FDM eyes and atropine-treated eyes receiving 4-weeks drug treatment using iTRAQ-MS proteomics. Combining the iTRAQ-MS and SWATH-MS datasets, a total of 29 confident proteins at 1% FDR were consistently quantified and matched, comprising 12 up-regulated and 17 down-regulated proteins which differed between FDM eyes and atropine treated eyes (iTRAQ: FC ≥ 1.5 or ≤0.67, SWATH: FC ≥ 1.4 or ≤0.71, p-value of ≤0.05). Bioinformatics analysis using IPA and STRING databases of these commonly regulated proteins revealed the involvement of the three commonly significant pathways: EIF2 signaling; glycolysis; and dopamine secretion. Additionally, the most significantly regulated proteins were closely connected to Alpha-synuclein (SNCA). Using immunostaining (n = 3), SNCA was further confirmed in the inner margin of the inner nuclear layer (INL) and spread throughout the inner plexiform layer (IPL) of the retina of guinea pigs. Conclusion: The molecular evidence using next-generation proteomics (NGP) revealed that retinal EIF2 signaling, glycolysis, and dopamine secretion through SNCA are implicated in atropine treatment of myopia in the FDM-induced guinea pig model.

Vaccination with a Brucella ghost developed through a double inactivation strategy provides protection in Guinea pigs and cattle

Vaccination can prevent and control animal brucellosis. Currently, live attenuated vaccines are extensively used to prevent Brucella infection. However, traditional vaccines such as live attenuated vaccines are associated with biological safety risks for both humans and animals. The bacterial ghost (BG) is a new form of vaccine with great prospects. However, bacterial cells cannot be completely inactivated by biological lysis, conferring a safety risk associated with the vaccine. In this study, we developed a Brucella abortus A19 bacterial ghost (A19BG) through a double inactivation strategy with sequential biological lysis and hydrogen peroxide treatment. This strategy resulted in 100% inactivation of Brucella, such that viable bacterial cells were not detected even at an ultrahigh concentration of 1010 colony-forming units/mL. Furthermore, A19BG had a typical BG morphology and good genetic stability. Moreover, it did not induce adverse reactions in guinea pigs. The levels of antibodies, interferon-γ, interleukin-4, and CD4+ T cells in guinea pigs inoculated with the A19BG vaccine were similar to those inoculated with the existing A19 vaccine. Immunization with A19BG conferred a similar level of protection with that of A19 against Brucella melitensis M28 in both guinea pigs and cattle. In conclusion, the combination of biological lysis and H2O2-mediated inactivation is a safe and effective strategy that can serve as a reference for the preparation of BG vaccines.

The Neural Basis of Skull Vibration Induced Nystagmus (SVIN).

I list a summary of the major clinical observations of SVIN in patients with total unilateral vestibular loss (TUVL) and show how basic results from neurophysiology can explain these clinical observations. The account integrates results from single neuron recordings of identified semicircular canal and otolith afferent neurons in guinea pigs in response to low frequency skull vibration with evidence of the eye movement response in cats to selective semicircular canal stimulation (both individual and combined) and a simple model of nystagmus generation to show how these results explain most of the major characteristics of SVIN.

Citrus limon Peel Essential Oil-Induced Type IV Hypersensitivity Reaction.

BackgroundSeveral studies have shown anti-inflammatory, anti-microbial, antifungal, and antioxidant effects from Citrus limon–peel essential oil (Cl-PEO). Cl-PEO can be developed as topical drugs for oral ulceration because of its potential active components. There have been no studies on the topical application of Cl-PEO inducing type IV hypersensitivity reaction.PurposeTo investigate the potential of Cl-PEO from Batu City to induce type IV hypersensitivity reactions based on clinical changes, lymphocytes, macrophages, IFNγ, andIL10 expression.MethodsThis study was adapted from a guinea pig maximization-test method in Indonesia and the guidance of ISO 10,993-10:2010, and conducted on 20 guinea pigs (Cavia cobaya) divided into a control group and a treatment group. The treatment group was given Cl-PEO and the control group CMC-Na. Clinical changes were observed, then tissue specimens taken for hematoxylin–eosin and immunohistochemistry staining.ResultsThere were no clinical changes after exposure. Lymphocyte and macrophage numbers and IFNγ and IL10 expression increased in the treatment group compared to the control group (p=0).ConclusionCl-PEO can induce type IV hypersensitivity reactions in guinea pigs based on cellular and molecular cytokines, but there are no clinical changes after topical application.

Macromolecular substances as a dangerous factor in traditional Chinese medicine injections were determined by size-exclusive chromatography.

Macromolecular substances in traditional Chinese medicine injections (TCMIs) are expected to be a main dangerous factor causing anaphylactic or anaphylactoid reaction. The main aim of the study was to verify the macromolecular substances' anaphylactic or anaphylactoid reaction in guinea pigs and establish a size-exclusive chromatographic method to detect them. The macromolecular substances from six TCMIs (Danshen injection, Dengzhanxixin injection, Honghua injection, Qingkailing injection, Shuanghuanglian injection and Shuxuening injection) were prepared by removing substances with molecular weight less than 10kDa with an ultra-filter. The anaphylactic and anaphylactoid reactions caused by original TCMIs, injections rich in or free of macromolecules were assayed in guinea pigs. The relationship between the amount of the macromolecular substances and peak area of chromatogram was established by size-exclusive chromatography. Injections free of macromolecules were not likely to cause anaphylactic and anaphylactoid reactions, but injections rich in macromolecular substances were more likely to do so. If the macromolecular substances with molecular weight bigger than 10kDa were removed, the signal of macromolecular substances in TCMIs was quantitatively reduced. All the results suggested that macromolecular substances in TCMIs are a dangerous factor causing safety problems, and the macromolecular substances can be quantitatively detected with size-exclusive chromatography.

Characterisation of the static offset in the travelling wave in the cochlear basal turn

In mammals, audition is triggered by travelling waves that are evoked by acoustic stimuli in the cochlear partition, a structure containing sensory hair cells and a basilar membrane. When the cochlea is stimulated by a pure tone of low frequency, a static offset occurs in the vibration in the apical turn. In the high-frequency region at the cochlear base, multi-tone stimuli induce a quadratic distortion product in the vibrations that suggests the presence of an offset. However, vibrations below 100 Hz, including a static offset, have not been directly measured there. We therefore constructed an interferometer for detecting motion at low frequencies including 0 Hz. We applied the interferometer to record vibrations from the cochlear base of guinea pigs in response to pure tones. When the animals were exposed to sound at an intensity of 70 dB or higher, we recorded a static offset of the sinusoidally vibrating cochlear partition by more than 1 nm towards the scala vestibuli. The offset’s magnitude grew monotonically as the stimuli intensified. When stimulus frequency was varied, the response peaked around the best frequency, the frequency that maximised the vibration amplitude at threshold sound pressure. These characteristics are consistent with those found in the low-frequency region and are therefore likely common across the cochlea. The offset diminished markedly when the somatic motility of mechanosensitive outer hair cells, the force-generating machinery that amplifies the sinusoidal vibrations, was pharmacologically blocked. Therefore, the partition offset appears to be linked to the electromotile contraction of outer hair cells.

Иммунопатогенные свойства SARS-CoV-2 как основа для выбора патогенетической терапии

Guinea-pigs were immunized via footpads with sheep red blood cells (SRBC) in saline. Histological examination of erythematous skin reaction was performed and effects of cyclophosphamide (CY) or BCG pre-treatment on the skin reaction were examined. Delayed-in-onset erythematous skin reaction accompanied by substantial basophil infiltration was elicited in guinea-pigs immunized with SRBC in saline. The erythema was augmented in size by CY which was injected 2 days before immunization. The reaction may be comparable to Jones-Mote type. In BCG pre-treated guinea-pigs, basophil infiltration at the skin reaction sites was reduced in number, but significant inhibition of macrophage migration was not detected in the presence of SRBC antigen. The reaction may be intermediate between Jones-Mote and the tuberculin type. Comparability of delayed skin reactions in guinea-pigs and delayed footpad reactions in mice or hamsters against SRBC is discussed.

Application of transdermal patches with new skin test reagents for detection of latent tuberculosis.

Introduction. Current intradermal tuberculin skin tests for latent tuberculosis infection (LTBI) based on purified protein derivative (PPD) have poor specificity.Aims. Developing a better skin test antigen as well as a simple skin patch test may improve and facilitate diagnostic performance.Methodology. Defined recombinant antigens that were unique to Mycobacterium tuberculosis (MTB), including two potential latency-associated antigens (ESAT-6 and Rv2653c) and five DosR-encoded latency proteins (Rv1996, Rv2031c, Rv2032, DevR and Rv3716c), were used as diagnostic skin test reagents in comparison with a standard PPD. The performance of the skin tests based on the detection of delayed-type hypersensitivity (DTH) reaction in guinea pigs sensitized to MTB and M. bovis bacille Calmette-Guérin (BCG) vaccine was evaluated.Results. The latency antigens Rv1996, Rv2031c, Rv2032 and Rv2653c and the ESAT-6 protein elicited less reactive DTH skin responses in MTB-sensitized guinea pigs than those resulting from PPD, but elicited no response in BCG-vaccinated guinea pigs. The remaining two latency antigens (DevR and Rv3716c) elicited DTH responses in both groups of animals, as did PPD. The reactivity of PPD in BCG-vaccinated guinea pigs was greater than that of any of the selected skin test reagents. Using stronger concentrations of selected skin test reagents in the patch test led to increased DTH responses that were comparable to those elicited by PPD in guinea pigs sensitized with MTB.Conclusion. Transdermal application of defined purified antigens might be a promising method for LTBI screening.

Microbiostatic and Synergistic Actions of Extract of Green Walnut Peel

The content of juglone in green walnut peel reach the highest in the period of July to August Juglone, extracts of green walnut peel and tee tree oil were tested in antimicrobial experiments against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. The results demonstrated that extract from green walnut peel, and juglone were microbiostatic for all the tested strains. Distinct synergic effects were observed with mixtures of tee tree oil and extract of green walnut peel. Microbiostatic effects on the four microorganisms was highest with a 1 to 10 ratio of tee tree oil and green walnut peel extracts. This mixture was essentially nontoxic and showed good biocompatibility. There were no irritating reactions observed in the repeated dermal irritation test in rabbits, no allergic reactions in guinea pigs and a very low irritating effect in the vaginal mucosa of rabbits. The mixture is promising for use in medical antibacterial products.

Primary skin irritation and dermal sensitization assay: In vivo evaluation of the essential oil from Piper sarmentosum Roxb.

Background: Piper sarmentosum Roxb. is a traditional medicine which can also be consumed as a vegetable. Despite the availability of a variety of toxicological data on extracts of this plant, to our knowledge, until now, no dermal toxicological tests have been conducted. The aim of the present study was, therefore, to carry out in vivo assays to verify the safety of application of P. sarmentosum extract gel on the skin. Materials and Methods: The essential oils were extracted from the dried leaves of P. sarmentosum by hydrodistillation and then formulated into a gel. An in vivo skin irritation test of the P. sarmentosum extract gel was then conducted on albino rabbits, and an in vivo sensitization test was carried out on albino guinea pigs. Results: For both abraded and non-abraded sites, the calculated primary irritation index value for P. sarmentosum was 2.55, indicating that topical use of a gel with P. sarmentosum (1.55%) is nonirritative. However, a dermal sensitization assay revealed mild sensitization effects in 1 out of 10 guinea pigs in response to the application. Histological analysis revealed a slight thickening of the stratum corneum epidermis layer in the guinea pigs' skin. Conclusion: Together, these results indicate that the gel with P. sarmentosum is safe for application on the skin, but may lead to sensitization upon repeated application.

Temporal Coding of Voice Pitch Contours in Mandarin Tones.

Accurate perception of time-variant pitch is important for speech recognition, particularly for tonal languages with different lexical tones such as Mandarin, in which different tones convey different semantic information. Previous studies reported that the auditory nerve and cochlear nucleus can encode different pitches through phase-locked neural activities. However, little is known about how the inferior colliculus (IC) encodes the time-variant periodicity pitch of natural speech. In this study, the Mandarin syllable /ba/ pronounced with four lexical tones (flat, rising, falling then rising and falling) were used as stimuli. Local field potentials (LFPs) and single neuron activity were simultaneously recorded from 90 sites within contralateral IC of six urethane-anesthetized and decerebrate guinea pigs in response to the four stimuli. Analysis of the temporal information of LFPs showed that 93% of the LFPs exhibited robust encoding of periodicity pitch. Pitch strength of LFPs derived from the autocorrelogram was significantly (p < 0.001) stronger for rising tones than flat and falling tones. Pitch strength are also significantly increased (p < 0.05) with the characteristic frequency (CF). On the other hand, only 47% (42 or 90) of single neuron activities were significantly synchronized to the fundamental frequency of the stimulus suggesting that the temporal spiking pattern of single IC neuron could encode the time variant periodicity pitch of speech robustly. The difference between the number of LFPs and single neurons that encode the time-variant F0 voice pitch supports the notion of a transition at the level of IC from direct temporal coding in the spike trains of individual neurons to other form of neural representation.

Preclinical study on adverse reactions of Xingnaojing injection

In this study, different batches of Xingnaojing injection products were first selected for pseudoallergic mice test, and the results showed that after injection of 6.6-fold clinical dose Xingnaojing injection, the mice showed a slight pseudoallergic reaction, while other mice injected with other batches of injections showed no obvious pseudoallergic reaction. Therefore, it is preliminarily believed that this mice model can effectively indicate the risk of pseudoallergic reactions in the clinical application of Xingnaojing injections. In addition, by changing some of the processes, a high concentration of Xingnaojing injection was prepared for mice pseudoallergic test and guinea pig systemic allergy test. The results showed no significant type Ⅰ allergic reaction in guinea pigs. Mild pseudoallergic reactions occurred in mice after a 6.6-fold clinical dose injection. Therefore, it is considered that for sensitive or idiosyncratic people, the concentration of certain chemical components in Xingnaojing injection will increase after entering the body, which may increase the risk of pseudoallergic reaction. However, due to the limitations of test models, the risk of Xingnaojing injection to induce allergic reactions cannot be ruled out. Finally, by increasing the content of borneol and Tween and (or) sodium chloride in Xingnnaojing Injection and testing its pseudoallergic reactions, the results showed that the combination of these three ingredients may produce new trace sensitization substance and induce pseudoallergic reactions.

A canine adenovirus type 2 vaccine vector confers protection against foot-and-mouth disease in guinea pigs

Vaccination is a key element in the control of foot-and-mouth disease (FMD). The majority of the antigenic sites that induce protective immune responses are localized on the FMD virus (FMDV) capsid that is formed by four virus-encoded structural proteins, VP1 to VP4. In the present study, recombinant canine adenovirus type 2 (CAV2)-based FMD vaccines, Cav-P1/3C R° and Cav-VP1 R°, respectively expressing the structural P1 precursor protein along with the non-structural 3C protein or expressing the structural VP1 protein of the FMDV strain O/FRA/1/2001, were evaluated as novel vaccines against FMD. A strong humoral immune response was elicited in guinea pigs (GP) following immunization with Cav-P1/3C R°, while administration of Cav-VP1 R° did not induce a satisfying antibody response in GP or mice. GP were then used as an experimental model for the determination of the protection afforded by the Cav-P1/3C R° vaccine against challenge with the FMDV strain O1 Manisa/Turkey/1969. The Cav-P1/3C R° vaccine protected GP from generalized FMD to a similar extent as a high potency double-oil emulsion O1 Manisa vaccine. The results of the present study show that CAV2-based vector vaccines can express immunogenic FMDV antigens and offer protection against generalized FMD in GP. This suggest that Cav-P1/3C R° FMDV vaccine may protect natural host species from FMD. In combination with an appropriate diagnostic test, the Cav-P1/3C R° FMDV vaccine may also serve as a marker vaccine to differentiate vaccinated from infected animals.

Sensitizing Capacities and Cross-Reactivity Patterns of Some Diisocyanates and Amines Using the Guinea-Pig Maximization Test. Can p-phenylenediamine be Used as a Marker for Diisocyanate Contact Allergy?

Background:Isocyanates are mainly considered respiratory allergens but can also cause contact allergy. Diphenylmethane-4,4′-diamine (4,4′-MDA) has been considered a marker for diphenylmethane-4,4′-diisocyanate (4,4′-MDI) contact allergy. Furthermore, overrepresentation of positive patch-test reactions top-phenylenediamine (PPD) in 4,4′-MDA positive patients have been reported.Objectives:To investigate the sensitizing capacities of toluene-2,4-diisocyanate (2,4-TDI) and PPD and the cross-reactivity of 4,4′-MDA, 2,4-TDI, dicyclohexylmethane-4,4′-diamine (4,4′-DMDA), dicyclohexylmethane-4,4′-diisocyanate (4,4′-DMDI), 4,4′-MDI and PPD.Methods:The Guinea Pig Maximization Test (GPMT) was used.Results:PPD was shown to be a strong sensitizer (p&lt;0.001). Animals sensitized to PPD showed cross-reactivity to 4,4′-MDA (p&lt;0.001). Animals sensitized to 4,4′-MDA did not show cross-reactivity to PPD. 8 animals sensitized to 2,4-TDI were sacrificed due to toxic reactions at the induction site and could thus not be fully evaluated.Conclusion:PPD was shown to be a strong sensitizer. However, it cannot be used as a marker for isocyanate contact allergy. On the other hand, positive reactions to 4,4′-MDA could indicate a PPD allergy. The intradermal induction concentration of 2,4-TDI (0.70% w/v) can induce strong local toxic reactions in guinea-pigs and should be lowered.