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The bispyridinium oxime HI-6 DMS is in development as an improved therapy for the treatment of patients exposed to organophosphorus nerve agents. The aim of the work described in this paper was to provide non-clinical data to support regulatory approval of HI-6 DMS, by demonstrating efficacy against an oxime-sensitive agent, GB and an oxime-resistant agent, GD. We investigated the dose-dependent protection afforded by therapy including atropine, avizafone and HI-6 DMS in guinea-pigs challenged with GB or GD. We also compared the efficacy of 30 mg.kg−1 of HI-6 DMS to an equimolar dose of the current in-service oxime P2S and the dichloride salt of HI-6 (HI-6 Cl 2). In the treatment of GB or GD poisoning there was no significant difference between the salt forms. The most effective dose of HI-6 DMS in preventing lethality following challenge with GB was 100 mg.kg−1; though protection ratios of at least 25 were obtained at 10 mg.kg−1. Protection against GD was lower, and there was no significant increase in effectiveness of HI-6 DMS doses of 30 or 100 mg.kg−1. For GD, the outcome was improved by the addition of pyridostigmine pre-treatment. These data demonstrate the benefits of HI-6 DMS as a component of nerve agent therapy. © Crown copyright (2023), Dstl. • A comprehensive assessment in the guinea-pig of the efficacy of HI-6 DMS. • HI-6 was given in combination with atropine and an anticonvulsant. • Therapy including HI-6 DMS was superior to the current oxime P2S for GB and GD. • Pyridostigmine pretreatment enhanced protection against GD poisoning. [ABSTRACT FROM AUTHOR]

Objectives: Ginger (Zingiber officinale Roscoe) is a popular edible herb consumed and known globally for its culinary and medicinal properties. Particularly in South Asia, the ginger rhizome is used in several Gastrointestinal (GI) related ailments. In this study, we report preliminary findings on the GI relaxant activity of the dried variety of ginger rhizome. Materials and Methods: Ginger rhizome was soaked in 70% aqueous-methanol and dried to give the extract (Gd.Ex). Segments of different isolated smooth muscle preparations were suspended in tissue baths. Results: Phytochemistry profiling showed that the extract has terpenoids, phenols, and alkaloids. On baseline of isolated tissues like rat stomach pylorus, rabbit jejunum, guinea-pig ileum and colon, and rat uterus, Gd.Ex was devoid of any stimulant effect up to 10 mg/mL. The extract was able to completely inhibit spasmogenicity induced with K+ 80 mM in stomach pyloric strips, indicating a Ca2+ Channel Blocking (CCB) mechanism. Gd.Ex in bolus (1-10 mg/mL) and cumulative dosing (0.3-3 mg/mL), showed a relaxant effect on spontaneously contracting baseline of rabbit jejunum. The extract was then tested against different standard GI stimulants like acetylcholine (ACh, 0.3 µM), histamine (0.3 µM), and K+ (50 mM) in guinea-pig ileum. Gd.Ex (3 mg/mL) pretreatment abolished the stimulant responses. A similar inhibitory effect of the extract (0.3-1 mg/mL) was observed in guinea-pig colon and rat uterus against ACh. Conclusion: The study shows the spasmolytic potential of dried ginger extract in different smooth muscle preparations. Together with the earlier published results of dried ginger in rat stomach fundus, this explains the benefit of ginger in potentiating gastric emptying and alleviating nausea. [ABSTRACT FROM AUTHOR]

Background: Furry animals are an important source of indoor allergens. Diagnosis of allergy to small pets such as guinea‐pigs still relies on animal dander extracts which do not allow to define the primary sensitization source. Objective: To identify major guinea‐pig allergens and to evaluate their potential as marker allergens for in vitro IgE‐diagnosis in comparison with dander extracts. Methods: A group of patients allergic to guinea‐pig (n = 29) and a group of patients allergic to cat and dog (n = 30) were recruited for the study. A panel of four guinea‐pig lipocalin allergens was expressed as recombinant proteins in E. coli. Specific IgE were quantified by ImmunoCAP and ELISA. Results: The combination of 4 guinea‐pig lipocalin allergens, including 2 new lipocalins, Cav p 1.0201 and Cav p 6.0101, and the previously characterized lipocalins Cav p 2 and Cav p 3, enabled the identification of 90% of all patients allergic to guinea‐pig. The vast majority had specific IgE to Cav p 1 (83%). Cav p 6 shares 54% sequence identity with Fel d 4 and Can f 6 and was found to be IgE‐cross‐reactive with these allergens. In the group of cat‐ and dog‐allergic patients, 73% had also specific IgE to guinea‐pig dander. However, only 27% of the cat /dog‐allergic patients had specific IgE to any of the non‐cross‐reactive guinea‐pig allergens Cav p 1, Cav p 2 or Cav p 3. The high prevalence of IgE to guinea‐pig dander could be explained by IgE‐cross‐reactivity among serum albumins and certain lipocalins. Conclusions and clinical relevance: The availability of specific allergen markers is essential for the assessment of primary sensitization, especially in polysensitized patients. The proposed panel of guinea‐pig allergens Cav p 1, Cav p 2 and Cav p 3 is a first step to component‐resolved IgE‐diagnosis of allergy to small furry pets. [ABSTRACT FROM AUTHOR]

Aim of the study was to assess the risk of any allergic reaction or food hypersensitivity resulting from topical application and chronic oral administration of the fruit of selected strawberry cultivars ('Elsanta' and 'Honeoye') from farms managed organically. Materials and methods. The plantations were managed according to organic (OFP) as compared to integrated production (IFP) systems. The experiments were performed on outbred young, adult, white albinotic guinea pigs (Dunkin Hartley). Fruit characteristics included total soluble solid content, titratable acidity, sugar, polyphenol content and macro- and micronutrients. Results. The most pronounced changes in guinea pig skin followed topical exposure to 'Elsanta' strawberries from plantations managed organically showed discrete, moderate or intense erythema and swelling. Chronic oral administration of selected fruit extracts did not cause any skin reactions in groups receiving 'Elsanta' or 'Honeoye' from organic or integrated productions. The skin prick test did not show any immediate skin reactions compared to exposure to 1% histamine hydrochloride solution. Conclusion. Organic method of strawberry production cannot be concerned as more allergenic one as compared to integrated system. Any strict relationship between type of cultivar and selected macro-, micronutrients contents or fruit characteristics on the possible increase in allergenicity risk, was not found, either. [ABSTRACT FROM AUTHOR]

Normal gut function relies on the activity of the enteric nervous system (ENS) found within the wall of the gastrointestinal tract. The structural and functional organization of the ENS has been extensively studied in the guinea pig small intestine, but less is known about colonic circuitry. Given that there are significant differences between these regions in function, observed motor patterns and pathology, it would be valuable to have a better understanding of the colonic ENS. Furthermore, disorders of colonic motor function, such as irritable bowel syndrome, are much more common. We have recently reported specialized basket‐like structures, immunoreactive for calbindin, that likely underlie synaptic inputs to specific types of calretinin‐immunoreactive neurons in the guinea‐pig colon. Based on detailed immunohistochemical analysis, we postulated the recipient neurons may be excitatory motor neurons and ascending interneurons. In the present study, we combined retrograde tracing and immunohistochemistry to examine the projections of circular muscle motor neurons, myenteric interneurons, and putative sensory neurons. We focused on neurons with immunoreactivity for calbindin, calretinin and nitric oxide synthase and their relationship with calbindin baskets. Retrograde tracing using indocarbocyanine dye (DiI) revealed that many of the nerve cell bodies surrounded by calbindin baskets belong to motor neurons and ascending interneurons. Unique functional classes of myenteric neurons were identified based on morphology, neuronal markers and polarity of projection. We provide evidence for three groups of ascending motor neurons based on immunoreactivity and association with calbindin baskets, a finding that may have significant functional implications. The myenteric plexus of guinea‐pig colon immunolabeled with calbindin (red), calretinin (blue) and nitric oxide synthase (green) showing dye filled neurons (yellow) traced from the circular muscle. [ABSTRACT FROM AUTHOR]

Objective: Sarin is an irreversible organophosphate cholinesterase inhibitor and a highly toxic, volatile warfare agent. Rats and guinea pigs exposed to sarin display cholinergic excitotoxicity which includes hyper-salivation, respiratory distress, tremors, seizures, and death. Here we focused on the characterization of the airways injury induced by direct exposure of the lungs to sarin vapor and compared it to that induced by the intramuscularly route. Materials and methods: Rats were exposed to sarin either in vapor (∼1LCT50, 34.2 ± 0.8 µg/l/min, 10 min) or by i.m. (∼1LD50, 80 µg/kg), and lung injury was evaluated by broncho-alveolar lavage (BAL). Results and discussion: BAL analysis revealed route-dependent effects in rats: vapor exposed animals showed elevation of inflammatory cytokines, protein, and neutrophil cells. These elevations were seen at 24 h and were still significantly higher compared to control values at 1 week following vapor exposure. These elevations were not detected in rats exposed to sarin i.m. Histological evaluation of the brains revealed typical changes following sarin poisoning independent of the route of administration. The airways damage following vapor exposure in rats was also compared to that induced in guinea pigs. The latter showed increased eosinophilia and histamine levels that constitutes an anaphylactic response not seen in rats. Conclusions: These data clearly point out the importance of using the appropriate route of administration in studying the deleterious effects of volatile nerve agents, as well as the selection of the appropriate animal species. Since airways form major target organs for the development of injury following inhalation toxicity, they should be included in any comprehensive evaluation of countermeasures efficacy. [ABSTRACT FROM AUTHOR]

Highlights • Effects of motilin on contraction of gastrointestinal (GI) tract were examined. • Two guinea-pig motilins caused contraction of rabbit duodenum by motilin receptor. • Two guinea-pig motilins did not cause any responses in the guinea-pig GI tract. • RT-PCR using various primer sets failed to amplify guinea-pig motilin mRNA. • Motilin system is not functional in regulation of GI motility in the guinea-pig. Abstract Motilin (MLN), a 22-amino-acid peptide hormone, is generally present in the mucosa of the upper gastrointestinal (GI) tract, mainly the duodenum of mammals, and it regulates GI motility, especially that related to interdigestive migrating contraction. However, MLN and its receptor are absent in mice and rats, and MLN does not cause any mechanical responses in the rat and mouse GI tracts. The guinea-pig is also a rodent, but expression of the MLN gene in the guinea-pig has been reported. In the present study, two guinea-pig MLNs, FIPIFTYSELRRTQEREQNKGL found in the Ensemble Genome Database (gpMLN-1) and FVPIFTYSELRRTQEREQNKRL reported by Xu et al. (2001) (gpMLN-2), were synthesized, and their biological activities were evaluated in the rabbit duodenum and guinea-pig GI tract in vitro. Both gpMLNs showed contractile activity in longitudinal muscle strips of the rabbit duodenum. The EC 50 values of gpMLN-1 and gpMLN-2 were slightly higher than that of human MLN (hMLN), but the maximum contractions were as same as that of hMLN. Treatment with GM109 and hMLN-induced receptor desensitization decreased the contractile activity of both gpMLNs, indicating that the two gpMLN candidates are able to activate the MLN receptor (MLN-R) of the rabbit duodenum. In guinea-pig GI preparations, hMLN and gpMLNs did not show any mechanical responses in circular muscle strips from the gastric antrum or in longitudinal strips of the duodenum, ileum and colon although acetylcholine and 1,1-dimethyl-4-phenylpiperazinium (DMPP) caused definite mechanical responses. The DMPP-induced neural responses in the gastric circular muscle and ileal longitudinal muscles were not modified by gpMLN-1. Even in the gastric and ileal strips with intact mucosa, no mechanical responses were seen with either of the gpMLNs. Furthermore, RT-PCR using various primer sets failed to amplify the gpMLN-2 mRNA. In conclusion, gpMLNs including one that was already reported and the other that was newly found in a database were effective to the rabbit MLN-R, whereas they did not cause any contractions or modification of neural responses in the guinea-pig GI tract, indicating that the MLN system is vestigial and not functional in regulation of GI motility in the guinea-pig as well as in other rodents such as rats and mice. [ABSTRACT FROM AUTHOR]

Medical countermeasures for acute poisoning by organophosphorus nerve agents are generally assessed over 24 h following poisoning and a single administration of treatment. At 24 h, the antinicotinic bispyridinium compound MB327 (1,10-(propane-1,3-diyl)bis(4- tert -butylpyridinium)) dimethanesulfonate is as effective as the oxime HI-6 against poisoning by soman, when used as part of a treatment containing atropine and avizafone. In this study, we hypothesised that an earlier endpoint, at 6 h, would be more appropriate for the pharmacokinetics and mechanism of action of MB327 and would therefore result in improved protection. MB327 diiodide (33.8 mg/kg) or the oxime HI-6 DMS (30 mg/kg), in combination with atropine and avizafone (each at 3 mg/kg) was administered intramuscularly to guinea pigs 1 min following subcutaneous soman and the LD 50 of the nerve agent was determined at 6 h after poisoning for each treatment. The treatment containing HI-6 gave a similar level of protection at 6 h as previously determined at 24 h (protection ratios 3.9 and 2.9, respectively). In contrast, the protection achieved by treatment containing MB327 showed a striking increase at 6 h (protection ratio >15.4) compared to the 24 h end point (protection ratio 2.8). The treatment gave full protection for at least 5 h against doses of soman up to 525 μg/kg; in contrast, mortality began in animals treated with HI-6 after 1 h. This study demonstrates the importance of using an appropriate end point and has shown that treatment including MB327 was far superior to oxime-based treatment for poisoning by soman, when assessed over a pharmacologically-relevant duration. The improved outcome was seen following a single dose of treatment: it is possible that additional doses to maintain therapeutic plasma concentrations would further increase survival time. Antinicotinic compounds therefore offer a promising addition to treatment, particularly for rapidly aging or oxime-insensitive nerve agents. [ABSTRACT FROM AUTHOR]

Abstract: The gastrointestinal (GI) tract is unique compared to all other internal organs; it is the only organ with its own nervous system and its own population of intrinsic sensory neurons, known as intrinsic primary afferent neurons (IPANs). How these IPANs form neuronal circuits with other functional classes of neurons in the enteric nervous system (ENS) is incompletely understood. We used a combination of light microscopy, immunohistochemistry and confocal microscopy to examine the topographical distribution of specific classes of neurons in the myenteric plexus of guinea‐pig colon, including putative IPANs, with other classes of enteric neurons. These findings were based on immunoreactivity to the neuronal markers, calbindin, calretinin and nitric oxide synthase. We then correlated the varicose outputs formed by putative IPANs with subclasses of excitatory interneurons and motor neurons. We revealed that calbindin‐immunoreactive varicosities form specialized structures resembling ‘baskets’ within the majority of myenteric ganglia, which were arranged in clusters around calretinin‐immunoreactive neurons. These calbindin baskets directly arose from projections of putative IPANs and represent morphological evidence of preferential input from sensory neurons directly to a select group of calretinin neurons. Our findings uncovered that these neurons are likely to be ascending excitatory interneurons and excitatory motor neurons. Our study reveals for the first time in the colon, a novel enteric neural circuit, whereby calbindin‐immunoreactive putative sensory neurons form specialized varicose structures that likely direct synaptic outputs to excitatory interneurons and motor neurons. This circuit likely forms the basis of polarized neuronal pathways underlying motility. [ABSTRACT FROM AUTHOR]

The allergic reactions to fruits are lesser known among food sensitivities. The most common fruits belonging to the Rosaceae family that might cause allergic reactions are apples, pears and peaches. However, little is known about the potential allergic reactions caused by another member of the Rosaceae, the cherry. The aim of this study was to assess the risk of any allergic reaction or food hypersensitivity resulting from topical application and chronic oral administration of cherry fruits. The cherry fruits ‘Sabina’ cv. were produced in the orchard in Dąbrowice according to the principles of integrated (IFP) and organic (OR) productions. Fruits of ‘Debreceni Bötermö’ cv. were produced in Dąbrowice (IFP), and in the orchard in Nowy Dwór (OR). The experiments were performed on 65 outbred young, adult, white albinotic guinea pigs (Dankin Hartley). Three procedures were applied: I. Guinea-Pig Maximization Test (GPMT); II. Chronic administration of fruits and III. Skin prick (Dreborg) test. The skin reactions based on GPMT or Dreborg tests revealed no differences between the two cherry cultivars ‘Sabina’ and ‘Debreceni’ obtained from integrated or organic production. Similarly, it was not observed of any effect of cultivars of cherries nor the type of fruits production on the guinea pig skin reaction as a result of chronic feeding with fruits.

African horse sickness (AHS) is a non-contagious viral disease of solipeds transmitted by Culicoides. The disease is endemic in most African countries. Past experience has shown that Italy is a country exposed to emerging infectious diseases endemic to Africa; an incursion of AHS virus together with the widespread presence of Culicoides vectors could be the cause of a serious epidemic emergency. A live attenuated vaccine containing seven of the nine viral serotypes, serotype 5 and 9 are excluded, is commercially available from Onderstepoort Biological Products. However, the use of live vaccines is a matter of endless disputes, and therefore inactivated or recombinant alternative products have been investigated over the years. Since research on AHS is hampered by the use of horses to evaluate vaccine potency, in a previous experiment serological response to serotypes 5 and 9 was assayed in guinea-pigs and horses. A durable and comparable serological response was observed in the two animal species. In the present study antibody response in horses and guinea-pigs, immunised with the inactivated-adjuvanted vaccine formulated with serotype 9, was tested over a period of 12 months. When immunity was challenged, horses were protected from infection and disease. Antibody response in horses and guinea-pigs compared favourably.

Monovalent, inactivated and adjuvanted vaccines against African horse sickness, prepared with serotypes 5 and 9, were tested on guinea-pigs to select the formulation that offered the greatest immunity. The final formulation of the vaccines took into account the immune response in the guinea-pig and the inflammatory properties of two types of adjuvant previously tested on target animals. A pilot study was subsequently conducted on horses using a vaccine prepared with serotype 9. The vaccine stimulated neutralising antibodies from the first administration and, after the booster dose, 28 days later; high antibody levels were recorded for at least 10 months. The guinea-pig appears to be a useful laboratory model for the evaluation of the antigenic properties of African horse sickness vaccines.

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Current organophosphorus nerve agent medical countermeasures do not directly address the nicotinic effects of poisoning. A series of antinicotinic bispyridinium compounds has been synthesized in our laboratory and screened in vitro. Their actions can include open-channel block at the nicotinic receptor which may contribute to their efficacy. The current lead compound from these studies, MB327 1,1′-(propane-1,3-diyl)bis(4- tert -butylpyridinium) as either the diiodide (I 2 ) or dimethanesulfonate (DMS) has been examined in vivo for efficacy against nerve agent poisoning. MB327 I 2 (0–113 mg kg −1 ) or the oxime HI-6 DMS (0–100 mg kg − 1 ), in combination with atropine and avizafone (each at 3 mg kg −1 ) was administered to guinea-pigs 1 min following soman poisoning. Treatment increased the LD 50 of soman in a dose-dependent manner. The increase was statistically significant ( p < 0.01) at the 33.9 mg kg −1 (MB327) or 30 mg kg −1 (HI-6) dose with a comparable degree of protection obtained for both compounds. Following administration of 10 mg kg −1 (i.m.), MB327 DMS reached plasma C max of 22 μM at 12 min with an elimination t 1/2 of 22 min. In an adverse effect study, in the absence of nerve agent poisoning, a dose of 100 mg kg −1 or higher of MB327 DMS was lethal to the guinea-pigs. A lower dose of MB327 DMS (30 mg kg −1 ) caused flaccid paralysis accompanied by respiratory impairment. Respiration normalised by 30 min, although the animals remained incapacitated to 4 h. MB327 or related compounds may be of utility in treatment of nerve agent poisoning as a component of therapy with atropine, anticonvulsant and oxime, or alternatively as an infusion under medical supervision. [ABSTRACT FROM AUTHOR]

Prostatic smooth muscle develops spontaneous myogenic tone which is modulated by autonomic neuromuscular transmission. This study aimed to investigate the role of purinergic transmission in regulating electrical activity of prostate smooth muscle and whether its contribution may be altered with age. Intracellular recordings were simultaneously made with isometric tension recordings in smooth muscle preparations of the guinea-pig prostate. Immunostaining for P2X1 receptors on whole mount preparations was also performed. In prostate preparations which generated spontaneous slow waves, electrical field stimulation (EFS)-evoked excitatory junction potentials (EJPs) which were abolished by guanethidine (10 μM), α-β-methylene ATP (10 μM) or pyridoxal phosphate-6-azophenyl-2,4-disulfonic acid (PPADS, 10 μM) but not phentolamine (1 μM). Consistently, immunostaining revealed the expression of P2X1 receptors on prostatic smooth muscle. EJPs themselves did not cause contractions, but EJPs could sum to trigger a slow wave and associated contraction. Yohimbine (1 μM) and 3,7-dimethyl-1-propargylxanthine (DMPX, 10 μM) but not propranolol (1 μM) potentiated EJPs. Although properties of EJPs were not different between young and aging guinea-pig prostates, ectoATPase inhibitor ARL 67156 (100 μM) augmented EJP amplitudes by 64.2 ± 29.6% in aging animals, compared to 22.1 ± 19.9% in young animals. These results suggest that ATP released from sympathetic nerves acts on P2X1 purinoceptors located on prostate smooth muscle to evoke EJPs, while pre-junctional α 2 -adrenergic and adenosine A 2 receptors may play a role in preventing excessive transmitter release. Age-related up-regulation of enzymatic ATP breakdown may be a compensatory mechanism for the enhanced purinergic transmission which would cause hypercontractility arising from increased ATP release in older animals. [ABSTRACT FROM AUTHOR]

The presence and intraorgan distribution of the acetylcholinesterase (AChE)- positive nerve structures in the guinea-pig spleen were studied by means of the direct thiocholine method. Visualized AChE-positive nerve fibres entered the guinea-pig spleen at its hilum in the vicinity of the splenic artery branches and intra parenchyma were gradually distributed to form thicker periarterial nerves and also fine adventitial nerve plexus. In described topography the AChE-positive nerve fibres were identified in association with the central artery running through the white pulp. Some of the perivascular nerve fibres associated with the central artery extended away and passed into the periarterial lymphatic sheath (PALS) to reach the marginal zone and in continuation entered into the mantle zone of lymphatic follicles. Several AChE-positive nerve fibres were seen in the red pulp but less in the splenic capsule. We did not find any AChE – positive nerve cells in the guinea-pig spleen.

Parasite loads of different tissues were assessed in guinea pig foetus after maternal infection. Twelve female guinea pigs were infected with 100 cysts of the 76 K strain of Toxoplasma gondii by the oral route. Inoculation was performed 20 ± 5 days (G20) or 40 ± 5 days (G40) after the beginning of gestation. Gestational age was determined by progesterone assay. Maternal and foetal organ samples were taken 60 days after the beginning of gestation. Parasite loads (from placenta, amniotic fluid (AF), cord blood (CB), foetal brain, liver, lung and spleen) were assessed by a real-time PCR quantification using fluorescence resonance energy transfer (FRET) hybridization probes on the Light Cycler®. Congenital transmission was proven by the presence of parasites in blood or tissue samples of the foetus in 84.6% (11/13) and 100 % (16/16) of cases after inoculation on G20 and G40 , respectively. The quantitative analysis of our results after inoculation at G20 and G40 has allowed us to determinate the positive parasitic loads as a function of the origin of the sample and the period of inoculation. The parasite loads expressed as log (parasite/g) were low in AF and CB samples: 1.49 ± 0.50 and 1.05 ± 0.10 at G20 and 1.21 ± 0.36 and 1.20 ± 0.42 at G40 respectively. In contrast the placenta and the different foetal tissues had higher parasite burdens: 2.89 ± 0.54 to 5.30 ± 0.51 at G20 and 2.81 ± 0.71 to 3.65 ± 0.59 at G40 . All the placentae were positive for parasites even in the two cases with no proven transmission. Real time quantitative PCR using the hybridization probe was a very sensitive and reproducible technique to study the kinetics of congenital toxoplasmosis in the guinea pig model wich is close to that of humans.

The author describes the first cases of spontaneous leishmaniasis in guinea-pigs, as verified for the first time, in Curitiba, at the Institute of Biology and Technological Research. Studying the inoculability of Paracoccidioide brasiliensis in guinea-pigs, he found animals which presented tumoral lesions in the ears and peritesticular skin. The examination of these tumors, mixed with a small drop of Giemsa's original solution, plus the exam of the rubbings of the same material, coloured by the May-Grunwald Giemsa after fixation by Heidenhein's solution and the histological exams of the cuts in the tumoral lesions revealed the presence of elements which possessed the same morphology and aspect of the LEISHMAN-DONOVANI corpuscles. In the meanwhile, a parasitosis by protozoarians of the Leishmania variety might have been suspected, because large macrophagi could be seen in the histological cuts, all parazitized, identical with those which are found in other cutaneous leishmaniosis. The author then proceeds to the experimental study of the sickness, first by endeavouring to obtain material for the inoculation and cultures, by means of punctures in the tumors. Part of the product of the punctures was sown in N. N. N. medium and part inoculated in other guinea-pigs. After the third day the cultures presented the flagellated forms of the parasite, free or grouped in rosettes in the culture liquid. All the guinea-pigs inoculated with part of the material obtained by puncturing and with the liquids of the cultures, reproduced the tumors found in the animals spontaneously infected. With a view to reproducing the same features of generalization which were observed in other experimental animals, with other strains of leishmania, new animals were inoculated after having been tarred and blocked in order to attempt the breaking down of possible natural resistences, which proved unnecessary, however, for the generalization went on of itself naturally and without artifice. Inoculations were made by the subcutaneous, intraperitonial, intrasplenic, intramedular, intracerebral and endovenous channels and by instillation in the conjunctive, in those guinea-pigs which received subcutaneous inoculations, the incubation period varied between 11 and 15 days, this period being longer when the internal channels were used, when it was generally one or two months before the lesions appeared. When the lesions are on the skin or when the inoculation is done there, the first manifestations of lesions are characterized by a slight thickening of the subcutaneous tissue, which, little by little, becomes more consistent, giving place to a tumoral growth which attains great volume and characterizes the most developed phase. The lesions, when metastatic, are localized mostly in the tegumentary extremities and periarticular zones, having the same appearance as the lesions observed by other researchers who have studied the infection of hamsters, mice and dogs infected by L. donovani, L. infantum and L. tropica. The experiments carried out in all the tumoral lesions in guinea-pigs, were positive for leishmania, where they were found free in the tissues or parasitizing large macrophagi. At times the tumors ulcerate and become covered with a crusty layer, easily detachable, covering a rosy surface of granulomatosis aspect. The spleen and lymphatic ganglia are the internal organs which most react, hypertrophy always being present, and it has been possible to re-isolate the parasite of these organs as well as those of the liver, suprarenal, testicle, medulla of the bones and cardiac blood. A series of sixty guinea-pigs were inoculated in the skin of the nose and sacrificed within anything from a few minutes' up to twenty-four hours' interval. The material obtained from these animals was fixed in Bouin-Hollande, included in paraffin and coloured by hematoxilin-eosine and Maxinow's hematoxilin-azur II-eosine. The study of the histological cuts in the different periods of evolution showed that the inflammatory process passes through a series of modifications which start by an acute inflammatory phase followed by a simple granulomatosis phase, finally followed by another characterized exclusively by large parasitized macrophagi - the macrophagi phase. During the period of evolution of the inflammatory lesion, the infiltrative phenomena are constant and are at first constituted of granulocited neutrophils, eosinophils and mononuclear cells, followed by a preponderance of monocytes and lastly by the sole presence of large parasitized macrophagi. The author compares his findings in the guinea-pigs with those in other animals inoculated with different strain of Leishmania, calling attention to a real dermatropism of the parasite under study to its dissemination through the lymphatic channels and to the histologycal lesions identical to those other leishmaniosis, principally by those produced by L. tropica.

Introduction: Mesenchymal stem cells (MSCs) have been identified as a viable treatment for inflammatory bowel disease (IBD). MSCs derived from bone marrow (BM-MSCs) have predominated in experimental models whereas the majority of clinical trials have used MSCs derived from adipose tissue (AT-MSCs), thus there is little consensus on the optimal tissue source. The therapeutic efficacies of these MSCs are yet to be compared in context of the underlying dysfunction of the enteric nervous system innervating the gastrointestinal tract concomitant with IBD. This study aims to characterise the in vitro properties of MSCs and compare their in vivo therapeutic potential for the treatment of enteric neuropathy associated with intestinal inflammation. Methods: BM-MSCs and AT-MSCs were validated and characterised in vitro. In in vivo experiments, guinea-pigs received either 2,4,6-trinitrobenzene-sulfonate acid (TNBS) for the induction of colitis or sham treatment by enema. MSCs were administered at a dose of 1×106 cells via enema 3 hours after the induction of colitis. Colon tissues were collected 24 and 72 hours after TNBS administration to assess the level of inflammation and damage to the ENS. MSC migration to the myenteric plexus in vivo was elucidated by immunohistochemistry and in vitro using a modified Boyden chamber assay. Results: Cells exhibited multipotency and a typical surface immunophenotype for validation as bona fide MSCs. In vitro characterisation revealed distinct differences in growth kinetics, clonogenicity and cell morphology between MSC types. In vivo, BM-MSCs were comparatively more effective than AT-MSCs in attenuating leukocyte infiltration and neuronal loss in the myenteric plexus. MSCs from both sources equally ameliorated body weight loss, gross morphological damage to the colon, changes in the neurochemical coding of neuronal subpopulations and the reduction in density of extrinsic and intrinsic nerve fibres innervating the colon. MSCs from both sources migrated to the myenteric plexus in in vivo colitis and in an in vitro assay. Conclusions: These data from in vitro experiments suggest that AT-MSCs are ideal for cellular expansion. However, BM-MSCs were more therapeutic in the treatment of enteric neuropathy and plexitis. These characteristics should be considered when deciding on the MSC tissue source. [ABSTRACT FROM AUTHOR]

The mucins secreted by the Brunner's glands and the duodenal goblet cells of the Guinea-pig and the house mouse were compared by conventional and FITC-conjugated lectin histochemistry. Methylation/saponification and sialidase digestion were performed prior to lectin binding to detect the residues subterminal to sulfated groups and sialic acid, respectively. In the Guinea-pig the Brunner's glands produce class-III stable sulfosialomucins. Sialic acid is mostly 2,6-linked to galactose or to N-acetylgalactosamine and is in part O-acetylated in C 7 , C 8 , and C 9 . Sulfated groups are probably linked to sialic acid and N-acetylgalactosamine. Terminal residuals of N-acetylglucosamine, galactose, N-acetylgalactosamine and fucose linked in α1,2, α1,3, and α1,4 are also present. Duodenal goblet cells of the Guinea-pig present a lower number of residuals in respect to the Brunner's glandular ones, with sialic acid and N-acetylgalactosamine subterminal to sulfated groups. In the house mouse the Brunner's glands produce class-III stable neutral mucins, binding to same lectins as in the Guinea-pig except for those specific to sialic acid. A diversity of fucosylated residuals higher than in the Guinea-pig is observed. The mouse duodenal goblet cells lack stable class-III mucins, have little sialic acid and present a lower number of residuals in respect to the correspondent Brunner's glands. Regulation of the acidic intestinal microenvironment, prevention of pathologies and hosting of microflora can explain the observed results and the differences observed between the two rodents. [ABSTRACT FROM AUTHOR]

Piperine (P), a sensory stimulant in black pepper, is an agonist on TRPV1 receptors. Earlier work has showed capsaicin-sensitive and -insensitive mechanisms of the contractile action of P on the intestine. The current isolated organ study in the guinea-pig ileum, urinary bladder and trachea (a) confirms the presence of such components of effect (ileum and bladder); (b) indicates TRPV1 involvement in the effect of 5 or 30 µmol/l of P on the basis of an inhibitory action of the antagonist BCTC (ileum); (c) indicates that HC 030031-sensitive TRPA1 receptors and nifedipine-sensitive Ca2+ channels contribute to the capsaicin-resistant contraction to 30 µmol/l P (ileum) and (d) shows that the contractile effect of P up to 100 µmol/l (guinea-pig trachea) or 30 µmol/l (guinea-pig urinary bladder) is capsaicin-sensitive and mediated by TRPV1 receptors/channels. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Ellagic acid (EA) has been shown to have antioxidant, antibacterial, and anti-inflammatory activities. In Uighur traditional medicine, Euphorbia humifusa Willd is used to treat fungal diseases, and recent studies suggest that it is the EA content which is responsible for its therapeutic effect. However, the effects of EA on antifungal activity have not yet been reported. This study aimed to investigate the inhibitory effect of EA on fungal strains both in vitro and in vivo. The minimal inhibitory concentration (MIC) was determined by the National Committee for Clinical Laboratory Standards (M38-A and M27-A2) standard method in vitro. EA had a broad spectrum of antifungal activity, with MICs for all the tested dermatophyte strains between 18.75 and 58.33 µg/ml. EA was also active against two Candida strains, with MICs between 25.0 and 75.0 µg/ml. It was inactive against Candida glabrata. The susceptibility of six species of dermatophytes to EA was comparable with that of the commercial antifungal, fluconazole. The most sensitive filamentous species was Trichophyton rubrum ( MIC = 18.75 µg/ml). Studies on the mechanism of action using an HPLC-based assay and an enzyme linked immunosorbent assay showed that EA inhibited ergosterol biosynthesis and reduced the activity of sterol 14 α-demethylase P450 (CYP51) in the Trichophyton rubrum membrane, respectively. An in vivo test demonstrated that topical administration of EA (4.0 and 8.0 mg/cm2) significantly enhanced the cure rate in a guinea-pig infection model of Trichophyton rubrum. The results suggest that EA has the potential to be developed as a natural antifungal agent. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: Asthma is associated with reversible airway obstruction, leucocyte infiltration, airways hyperresponsiveness (AHR), and airways remodeling. Fluid accumulation causes pulmonary edema contributing to airways obstruction. We examined the temporal relationship between the late asthmatic response (LAR) following allergen challenge of sensitized guinea-pigs and pulmonary edema measured by magnetic resonance imaging (MRI). Materials and Methods: Ovalbumin (OVA) sensitized guinea-pigs received either a single OVA inhalation (acute) or nine OVA inhalations at 48 h intervals (chronic). Airways obstruction was measured as specific airways conductance (s Gaw) by whole body plethysmography. AHR to inhaled histamine and bronchoalveolar lavage for leucocyte counts were measured 24 h after a single or the final chronic ovalbumin challenges. MRI was performed at intervals after OVA challenge and high-intensity edemic signals were quantified. Results: Ovalbumin caused early bronchoconstriction, followed at 7 h by an LAR and at 24 h AHR and leucocyte influx. The bright-intensity MRI edema signal, peaking at 7 h, was significantly ( P < .05) greater after chronic (9.0 ± 0.7 × 103 mm3) than acute OVA (7.6 ± 0.2 × 103 mm3). Dexamethasone treatment before acute OVA abolished the AHR and LAR and significantly reduced eosinophils and the bright-intensity MRI edema from 9.1 ± 1.0 to 6.4 ± 0.3 × 103 mm3. Conclusion: We show a temporal relationship between edema and the LAR and their parallel reduction, along with eosinophils and AHR, by dexamethasone. This suggests a close causative association between pulmonary edema and impaired airways function. [ABSTRACT FROM AUTHOR]

Background: The guinea-pig is an excellent animal model for studying cardiopulmonary physiology/pharmacology. Interestingly, it also possesses a number of drug-metabolizing enzymes found in humans, such as CYP1A, CYP2D and CYP3A. Objective: To evaluate the hypothesis that the guinea-pig also expresses a functional CYP2C drug-metabolizing enzyme and the P-glycoprotein (P-gp) drug transporter in various tissues. Methods: cDNAs encoding CYP2C and P-gp were obtained from guinea-pig liver or small intestine and sequenced. Western blotting was performed to confirm the expression of CYP2C and P-gp. The functional enzymatic activity of guinea-pig CYP2C was evaluated with microsomal preparations using diclofenac and tolbutamide as specific drug substrates in HPLC analyses. To further study both P-gp and CYP2C functional activities, the guinea-pig ABCB1/MDR1 and CYP2C genes were cloned. The recombinant plasmids were then transfected in HEK293 (human embryonic kidney) cells and either calcein-acetoxymethyl ester (AM) accumulation assays or 14,15-EET/DHET formation experiments were performed to evaluate either P-gp transport activity or CYP2C epoxygenase activity, respectively. The guinea-pig tissue distribution of P-gp was studied by Western blotting. Results: Functional expression of CYP2C was demonstrated in guinea-pig liver microsomal preparations. CYP2C-mediated biotransformation of diclofenac and tolbutamide were shown. Expression of P-gp protein was detected in guinea-pig liver and small intestine. Functional activity of guinea-pig P-gp was demonstrated in ABCB1/MDR1-transfected cells. GP- CYP2C-transfected cells also showed functional epoxygenase activity. Conclusion: The guinea-pig expresses functional CYP2C and P-gp, thus suggesting its usefulness for further validating data obtained with other animal models in drug biotransformation/transport studies. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study was designed to examine the effects of adrenomedullin (AM) on airway epithelial cells. Primary cultures of guinea-pig tracheal epithelial cells and the human bronchiolar epithelial cell line NCI-H441 were used. Intracellular cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), prostaglandin E2 (PGE2), and stable end-products of nitric oxide were assayed. Adrenomedullin (10−6 mol/L) stimulated cAMP production in guinea-pig epithelial cells. Indomethacin (10−5 mol/L) significantly decreased the basal level of intracellular cAMP in guinea-pig epithelial cells, but not in NCI-H441 cells. However, AM did not stimulate production of PGE2, a major product that can increase cAMP formation. In the case of NCI-H441 cells, AM (10−8 – 10−6 mol/L) did not significantly affect intracellular cGMP levels or nitrite content in conditioned medium. Adrenomedullin and calcitonin gene-related peptide (CGRP) each stimulated cAMP production in NCI-H441 cells, but AM-stimulated cAMP production was antagonized by the CGRP fragment CGRP8–37. These findings suggest that AM stimulates cAMP production and functionally competes with CGRP for binding sites in airway epithelial cells, at least in human epithelial cells, but that it does not stimulate the release of PGE2 and nitric oxide. Though cyclooxygenase products contribute to some extent to cAMP formation in guinea-pigs, AM independently stimulates intracellular cAMP formation in airway epithelial cells.

Although adrenergic β2-agonist-induced smooth muscle relaxation has been attributed to increased intracellular cyclic AMP (cAMP), a relaxation response has been observed at low β2-agonist concentrations that do not cause increased cAMP To elucidate the mechanism of tracheal muscle relaxation induced by low concentrations of β2-agonists, we used a guinea-pig skinned tracheal smooth muscle preparation to examine the effects on the contractile protein system. The isotonic contraction of β-escin-treated skinned tracheal muscle from guinea-pig was measured. When the intracellular Ca2+ concentration was maintained at 1 μmol/L in the presence of guanosine 5′-triphosphate (GTP; 100 μmol/L), neither isoproterenol (10nmol/L) nor salbutamol (60 nmol/L) affected Ca2+ sensitivity, but a significant decrease in Ca2+ sensitivity was observed in the presence of okadaic acid (1 μmol/L). The decrease in Ca2+ sensitivity was a slow response and was blocked by pretreatment with propranolol (1 μmol/L). Forskolin (1 μmol/L) did not affect Ca2+ sensitivity. These results suggest that adrenergic b 2-agonists may activate protein phosphatase through an unknown pathway involving the β2-receptor, which enhances dephosphorylation of the myosin light chain and/or thin filament proteins, resulting in relaxation of the tracheal smooth muscle.

The aim of the present study was to compare the effects of selective phosphodiesterase (PDE) 3, 4 and 5 inhibitors on antigen-induced airway hyperresponsiveness in sensitized guinea-pigs. When the sensitized guinea-pigs were orally pre-treated with the selective PDE4 inhibitor, Ro 20-1724 (30 mg/kg), and studied 48 h after OA, a significant reduction (p

Patients with overactive bladder often exhibit abnormal bladder contractions in response to intravesical cold saline (positive ice-water test). The molecular entity involved in cold sensation within the urinary bladder is unknown, but a potential candidate is the ion channel, transient receptor potential (melastatin)-8 (TRPM8). The objective of the present study was to investigate the role of TRPM8 in a bladder-cooling reflex evoked in anaesthetised guinea-pigs that is comparable to the positive ice-water test seen in patients. Guinea-pig TRPM8 was cloned from L6 dorsal root ganglia (DRG) and expressed in HEK293 cells. Functional agonist- and cold-induced Ca 2+ influx and electrophysiology assays were performed in these cells, and for comparison in HEK293 cells expressing human TRPM8, using a novel TRPM8 antagonist, the S-enantiomer of 1-phenylethyl 4-(benzyloxy)-3-methoxybenzyl (2-aminoethyl) carbamate hydrochloride (PBMC). Potency data from these assays was used to calculate intravenous infusion protocols for targeted plasma concentrations of PBMC in studies on micturition reflexes evoked by intravesical infusion of menthol or cold saline in anaesthetised guinea-pigs. Tissue expression of TRPM8 in guinea-pig bladder, urethra and in dorsal root ganglia neurones traced from the bladder was also investigated. TRPM8 mRNA and protein were detected in L6 dorsal root ganglia, bladder urothelium and smooth muscle. PBMC antagonised in vitro activation of human and guinea-pig TRPM8 and reversed menthol and cold-induced facilitation of the micturition reflex at plasma concentrations consistent with in vitro potencies. The present data suggest that the bladder-cooling reflex in the guinea-pig involves TRPM8. The potential significance of TRPM8 in bladder disease states deserves future investigation. [ABSTRACT FROM AUTHOR]

One feature of allergic asthma, the EAR (early allergic reaction), is not present in the commonly used mouse models. We therefore investigated the mediators involved in EAR in a guinea-pig in vivo model of allergic airway inflammation. Animals were sensitized using a single OVA (ovalbumin)/alum injection and challenged with aerosolized OVA on day 14. On day 15, airway resistance was assessed after challenge with OVA or MCh (methacholine) using the forced oscillation technique, and lung tissue was prepared for histology. The contribution of mast cell mediators was investigated using inhibitors of the main mast cell mediators [histamine (pyrilamine) and CysLTs (cysteinyl-leukotrienes) (montelukast) and prostanoids (indomethacin)]. OVA-sensitized and challenged animals demonstrated AHR (airway hyper-responsiveness) to MCh, and lung tissue eosinophilic inflammation. Antigen challenge induced a strong EAR in the sensitized animals. Treatment with a single compound, or indomethacin together with pyrilamine or montelukast, did not reduce the antigen-induced airway resistance. In contrast, dual treatment with pyrilamine together with montelukast, or triple inhibitor treatment, attenuated approximately 70% of the EAR. We conclude that, as in humans, the guinea-pig allergic inflammation model exhibits both EAR and AHR, supporting its suitability for in vivo identification of mast cell mediators that contribute to the development of asthma. Moreover, the known mast cell mediators histamine and leukotrienes were major contributors of the EAR. The data also lend further support to the concept that combination therapy with selective inhibitors of key mediators could improve asthma management. [ABSTRACT FROM AUTHOR]

Background: The importance of the lung parenchyma in the pathophysiology of asthma has previously been demonstrated. Considering that nitric oxide synthases (NOS) and arginases compete for the same substrate, it is worthwhile to elucidate the effects of complex NOS-arginase dysfunction in the pathophysiology of asthma, particularly, related to distal lung tissue. We evaluated the effects of arginase and iNOS inhibition on distal lung mechanics and oxidative stress pathway activation in a model of chronic pulmonary allergic inflammation in guinea pigs. Methods: Guinea pigs were exposed to repeated ovalbumin inhalations (twice a week for 4 weeks). The animals received 1400 W (an iNOS-specific inhibitor) for 4 days beginning at the last inhalation. Afterwards, the animals were anesthetized and exsanguinated; then, a slice of the distal lung was evaluated by oscillatory mechanics, and an arginase inhibitor (nor-NOHA) or vehicle was infused in a Krebs solution bath. Tissue resistance (Rt) and elastance (Et) were assessed before and after ovalbumin challenge (0.1%), and lung strips were submitted to histopathological studies. Results: Ovalbumin-exposed animals presented an increase in the maximal Rt and Et responses after antigen challenge (p<0.001), in the number of iNOS positive cells (p<0.001) and in the expression of arginase 2, 8- isoprostane and NF-kB (p<0.001) in distal lung tissue. The 1400 W administration reduced all these responses (p<0.001) in alveolar septa. Ovalbumin-exposed animals that received nor-NOHA had a reduction of Rt, Et after antigen challenge, iNOS positive cells and 8-isoprostane and NF-kB (p<0.001) in lung tissue. The activity of arginase 2 was reduced only in the groups treated with nor-NOHA (p <0.05). There was a reduction of 8-isoprostane expression in OVA-NOR-W compared to OVA-NOR (p<0.001). Conclusions: In this experimental model, increased arginase content and iNOS-positive cells were associated with the constriction of distal lung parenchyma. This functional alteration may be due to a high expression of 8-isoprostane, which had a procontractile effect. The mechanism involved in this response is likely related to the modulation of NF-kB expression, which contributed to the activation of the arginase and iNOS pathways. The association of both inhibitors potentiated the reduction of 8-isoprostane expression in this animal model. [ABSTRACT FROM AUTHOR]

The inhibitory effect of aqueous-ethanolic extract of Zataria multiflora Boiss (Labiatae) and carvacrol on histamine (H1) receptors was examined on tracheal chains of guinea-pigs. The effects of three concentrations of aqueous-ethanolic extract, carvacrol, 10 n m chlorpheniramine, and saline on histamine (H1) receptors were tested on three groups of guinea-pig tracheal chains as follows: incubated trachea with (i) indomethacin ( n = 9), (ii) indomethacin, propranolol, and atropine ( n = 7), and (iii) indomethacin and propranolol ( n = 6). The EC50 (effective concentration of histamine causing 50% of maximum response) obtained in the presence of chlorpheniramine for all concentrations of the extract and carvacrol in all three groups was significantly higher than that of saline ( P < 0.001 for all cases). The EC50 obtained in the presence of all concentrations of extract in groups 2 and 3 was lower than group 1 and in group 3 lower than group 2 ( P < 0.01 to P < 0.001). However, EC50 obtained in the presence of all concentrations of carvacrol in group 3 and two higher concentrations in group 2 was higher than that of group 1 ( P < 0.01 to P < 0.001). There was no significant difference in the maximum response obtained in the presence of different concentrations of extract and carvacrol between three groups. There was a parallel rightward shift in concentration-response curves obtained in the presence of all concentrations of the extract and carvacrol in all three groups. These results indicated an inhibitory effect of Z. multiflora and its constituent carvacrol on histamine H1 receptors. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: We have recently introduced the use of mammalian cardiac tissue slices for in vitro drug testing purposes. Here we show how this method can be applied for long-term studies in safety pharmacology. Methods: In freshly prepared cardiac slices from guinea-pig or rat ventricle, extracellular field potentials (FP) and intracellular action potentials (AP) were recorded in response to electrical stimulation using the 4-channel heart slice screening system ‘Synchroslice’. To assess viability of the slices on consecutive days after preparation, drug effects on FP/AP parameters, like duration and latency, were monitored. Results: In the presence of the potassium channel blocker E4031 (1μM), FP and AP duration (FPD and APD) were significantly increased (FPD, 39.0%; APD, 28.1%) in guinea-pig ventricular slices. Similar changes were observed 24–28h after slice preparation (FPD, 48.6%; APD, 25.4%). Furthermore, AP duration was reduced in the presence of the calcium channel blocker nifedipine (10μM) on the day of preparation (40.5%) and 24–28h later (38.7%). In contrast, in the presence of the potassium channel blocker 4-aminopyridine (30mM) AP duration was prolonged 4.95 and 4.19-fold, 2–8h and 24–28h after preparation, respectively. Finally, FP propagation was repeatedly slowed down by the gap junction blocker carbenoxolone (30μM), as revealed from FP onset latency increases observed on three consecutive days (2–8h after preparation, 93.0%; 24–28h, 76.8%, 48–56h, 61.7%). Discussion: Freshly isolated cardiac slices reproduced established physiological and pharmacological responses for more than 24h after preparation. Thus, cardiac slices can be used for several days after preparation which makes them a robust model for electrophysiological studies. We propose that cardiac slices can become a versatile tool in heart research and risk assessment of drugs. [Copyright &y& Elsevier]