Directional left-sided asymmetry of adrenals in experimentally domesticated animals

Directional left-sided asymmetry of the adrenals was typical of black and silver foxes, American minks, and gray rats selected by their behavior. In domesticated, but to a greater extent, in aggressive animals, the weight of the left adrenal and the width of its medulla and cortex markedly surpassed the corresponding parameters of the right adrenal. In aggressive animals enlargement of the left adrenal cortex was associated with widening of the zona reticularis, while in domesticated animals with enlargement of the zona fasciculata.     

Relationship between hyponeophagia and adrenal cortex function in farmed foxes

The adrenal cortex function of farmed blue (Alopex lagopus) and silver foxes (Vulpes vulpes) differing in their reaction in the feeding test were assessed. The urine cortisol:creatinine ratio was lower for those animals eating in the feeding test in comparison to those not eating in both species. In addition, eater silver foxes had lower baseline serum cortisol concentration and also lower serum cortisol concentration 2 h after ACTH administration than noneaters. There were no differences in any serum cortisol levels between the eater and noneater blue foxes. The weights of body and adrenals did not differ between confident and fearful animals in either species. The present study demonstrates that animals not eating in the feeding test may have higher fearfulness and be more stressed than animals eating.     

Quantitation of Clostridium botulinum organisms and toxin in the feces of an infant with botulism.

A 4-month-old boy presented with symptoms and signs characteristic of infant botulism. Examination of feces revealed Clostridium botulinum type B and type B toxin. The numbers of C. botulinum and the amount of toxin in feces were measured throughout the 4-week period in hospital. The maximum numbers and amounts were detected in a fecal specimen collected 16 days after admission: this contained 8.4 X 10(6) C. botulinum type B colony-forming units and 61,440 mouse 100% lethal doses of type B toxin per g (wet weight) of feces. This latter figure is the highest fecal toxin titer reported yet for a case of infant botulism. By day 16, however, substantial improvement in the patient's clinical condition had occurred. This suggests that initiation of recovery from infant botulism is not necessarily preceded by a reduction in the numbers of C. botulinum organisms and the quantity of toxin in the gut.     

Abdominal aortal plexus in fur animals (order Carnivora)

Abdominal aortal plexus was studied in foxes, polar foxes, sables and minks using macro-microscopic method of V.P. Vorobjov. Nerve ganglia of the abdominal aortal plexus in all examined fur animals are located at the roots of the largest arterial vessels originating from abdominal aorta and they are represented by paired abdominal, unpaired cranial mesenterial (excluding minks), inconstant visceral and aorto-renal, plural intermesenterial, single or plural caudal mesenterial nerve ganglia.     

Motor responses of the urinary bladder and skeletal muscle in Botulinum intoxicated rats

1. Type A or type D botulinum toxin administered to rats did not produce a generalized paralysis of skeletal muscles at the time of ventilatory arrest. However, if survival was extended by artificial ventilation complete blockade of neuromuscular transmission developed 6.5 hr after 100 MLD of type D and 5 hr after 1000 MLD of type A toxin. The onset of paralysis of a muscle was shortened by repetitive stimulation of the motor nerves.2. There was no consistent blockade of parasympathetically innervated viscera in animals dying after type A toxin. Animals given type D toxin displayed mydriasis and urinary retention before death.3. Motor responses to electrical stimulation, of bladder preparations in vitro were more vulnerable to type D than to type A toxin. When somatic paralysis was complete in animals treated with type A or type D toxin the excised bladders produced pressure elevations 45 and 25%, respectively, of control preparations.4. During electrical stimulation of bladder preparations nearly paralysed by either toxin, the ACh release was significantly diminished from controls. In the rat bladder botulinum toxin specifically disrupted the liberation of mediator from post-ganglionic nerve endings.     

Characterization of a neurotoxigenic Clostridium butyricum strain isolated from the food implicated in an outbreak of food-borne type E botulism.

Neurotoxigenic Clostridium butyricum was isolated from the food implicated in an outbreak of clinically diagnosed type E botulism in China. PCR assay showed that the isolate (LCL 155) contained the type E botulinum toxin gene. This appears to be the first report of neurotoxigenic C. butyricum causing food-borne botulism.     

Kinetics of growth and toxigenicity of Clostridium botulinum in experimental wound botulism.

An animal model of wound botulism was developed in mice using an inoculum of Clostridium botulinum type A spores. The number of C. botulinum in infected wounds was quantitated by culturing on egg yolk agar, and the level of C. botulinum toxin in infected wound tissue was measured by a bioassay in mice and by an enzyme-linked immunosorbent assay. All infected mice receiving no further treatment developed neuroparalytic symptoms consistent with botulism after an incubation period of ca. 48 h, and all of these animals died. Serotherapy with C. botulinum type A antitoxin initiated 24 h postchallenge reduced the mortality rate to 5%. Treatment with metronidazole 2 to 24 h postchallenge resulted in recovery rates of 40 to 91%.     

Quantities of Clostridium botulinum organisms and toxin in feces and presence of Clostridium botulinum toxin in the serum of an infant with botulism.

A 7-week-old boy presented with symptoms and signs characteristic of infant botulism, and the diagnosis was confirmed by the detection of Clostridium botulinum type A organisms and toxin in the feces. The levels of organisms and toxin in the feces were measured throughout the 81-day period in hospital. The maximum levels detected were 2.46 x 10(8) C. botulinum type A colony-forming units and 64,000 mouse 100% lethal doses of type A toxin per g (wet weight) of feces. C. botulinum toxin was also detected in two samples of the patient's serum, collected 3 and 10 days after admission. Improvement in the patient's clinical condition occurred before the levels of organisms and toxin in the feces reached their maxima. A slight improvement may also have occurred while toxin was still present in the serum.     

Histopathological effect of botulinum C2 toxin on mouse intestines

Botulinum C2 toxin has histopathological activity in the mouse intestine and induces fluid accumulation in intestinal loops. The toxin caused degenerative and necrotic changes in the intestinal mucosa: intracellular vacuolization of epithelial cells, desquamation and necrosis of the villous epithelium, intercellular edema, and infiltration of lymphocytes and histiocytes. The detectable changes in the morphology of the intestinal mucosa preceded the increase in fluid accumulation in intestinal loops. Intraluminal injection of botulinum C2 toxin also induced the leakage of plasma protein into the intestinal lumen as determined by the extravasation of Evans blue. In contrast to botulinum C2 toxin, cholera and Clostridium perfringens enterotoxin controls caused a very slight protein leakage, although these toxins induced marked fluid accumulation in intestinal loops. The results indicate that the mode of action of botulinum C2 toxin in eliciting the secretory response is distinguishable from those of cholera and C. perfringens enterotoxins and suggest that botulinum C2 toxin induces the secretory response by cytopathic effect(s) on the epithelial cells of the intestine.     

Botulism in ostriches (Struthio camelus)

An outbreak of botulism in ostriches (Struthio camelus) is described. Some birds became totally paralysed, and many developed paresis and ataxia. Clostridium botulinum type C and its toxin were found in the remains of an ostrich carcass collected from the camp in which the birds were kept. Toxin could not be demonstrated in the serum of affected ostriches. Treatment with specific antitoxin resulted in total recovery of almost all the birds.     

Investigation of a type C/D botulism outbreak in free-range laying hens in France

In 2014, a botulism outbreak in a flock of laying hens was investigated in France. In the flock of 5020 hens, clinical signs of botulism occurred at 46 weeks of age. A type C/D botulism outbreak was confirmed using the mouse lethality assay for detection of botulinum toxin in serum and a real-time PCR test to detect Clostridium botulinum in intestinal contents. The disease lasted one week with a mortality rate of 2.6% without recurrence. Botulism in laying hens has rarely been reported. Five monthly visits were made to the farm between December 2014 and May 2015 for a longitudinal study of the persistence of C. botulinum in the poultry house after the outbreak, and to assess egg contamination by C. botulinum. Several samples were collected on each visit: in the house (from the ventilation circuit, the egg circuit, water and feed, droppings) and the surrounding area. Thirty clean and 30 dirty eggs were also swabbed at each visit. In addition, 12 dirty and 12 clean eggs were collected to analyse eggshell and egg content. The samples were analysed using real-time PCR to detect type C/D C. botulinum. The bacterium was still detected in the house more than 5 months after the outbreak, mostly on the walls and in the egg circuit. Regarding egg contamination, the bacteria were detected only on the shell but not in the content of the eggs. Control measures should therefore be implemented throughout the egg production period to avoid dissemination of the bacteria, particularly during egg collection.     

Establishment of a monoclonal antibody recognizing an antigenic site common to Clostridium botulinum type B, C1, D, and E toxins and tetanus toxin.

The partial amino acid sequence of the light-chain (Lc) component of Clostridium botulinum type C1 toxin was determined. The sequence was quite similar to those of the other types of botulinum and tetanus toxins. Nine monoclonal antibodies against botulinum type E toxin were established by immunizing BALB/c mice with type E toxoid or its Lc component. Six antibodies reacted with the heavy-chain component and three reacted with the Lc component of the toxin. One of the latter three antibodies reacted with botulinum type B, C1, and D toxins and tetanus toxin, as well as botulinum type E toxin. This antibody recognized the Lc components of these toxins, indicating that there exists one common antigenic determinant on the Lc regions of these toxins.     

Fluorescent-antibody reagents for the identification of Clostridium botulinum.

Fluorescent-antibody reagents were prepared against vegetative cells of representative strains of each physiological group and toxin type of Clostridium botulinum known to have caused botulism in humans. A fluorescent-antibody reagent was also prepared for C. botulinum type G, which has been isolated from autopsy specimens but which has not clearly been implicated in botulism. These fluorescent-antibody reagents were evaluated against 200 strains of C. botulinum and 64 strains of other clostridia. Each reagent reacted with at least a 2+ intensity with all of the strains in its same toxin type and physiological group. Ninety-seven percent of the strains gave at least a 3+ reaction with the homologous group or toxin type reagent. Some cross-reactions occurred with reagents against different toxin type strains within a physiological group; there was less cross-reaction between physiological groups and very little reactivity of C. botulinum reagents with nontoxigenic organisms. Absorption of cross-reacting antibodies was not successful. Certain reagents could be used for presumptive laboratory identification of C. botulinum strains causing botulism, especially in infants. The type G reagent provided a good means of identifying C. botulinum type G, which lacks the lipase marker and whose toxigenicity may be more difficult to demonstrate in mixed cultures. There was a serological relationship between C. botulinum type G and some strains of Clostridium subterminale. This relationship provided evidence of differences between strains of C. botulinum type G isolated in two different countries.     

Detection of Clostridium botulinum type A toxin by enzyme-linked immunosorbent assay with antibodies produced in immunologically tolerant animals.

Immunological tolerance is a state of unresponsiveness to foreign substances (antigens) which can develop in human and animal species as the result of continued exposure to antigens early in life. We utilized this principle for the preparation of antibodies against Clostridium botulinum type A toxin. By selective suppression of the immunological response of rabbits to unwanted antigens and subsequent immunization with a toxoid, we were able to produce a specific type A antitoxin without the need to purify the toxin. Despite cross-reactivity with C. botulinum type B, our type A antitoxin was otherwise specific since it did not react with culture filtrates of nontoxigenic variants of type B, any other C. botulinum type (C, D, E, F, and G), nor with 18 other Clostridium species, including Clostridium sporogenes. Using this antitoxin, we developed a sensitive enzyme-linked immunosorbent assay for detection of C. botulinum type A toxin.     

Comparison of toxins of Clostridium butyricum and Clostridium botulinum type E.

The toxin of Clostridium butyricum strains isolated from two infants with botulism is neutralized by antitoxin for type E botulinum toxin. This toxin and that of a C. botulinum type E strain were purified by the same protocol. Both toxins were Mr 145,000 proteins which, when activated with trypsin, were composed of an H subunit of Mr 105,000 and an L subunit of Mr 50,000. The activated specific toxicity of purified butyricum toxin based on an intravenous assay was 2 X 10(8) mouse 50% lethal doses (LD50s)/mg of protein, but that based on an intraperitoneal assay was 7 X 10(7) LD50s/mg, compared with 6 X 10(7) LD50s/mg for type E toxin as determined by both methods. Immunodiffusion tests with antitoxin raised with type E toxin indicated that the two toxins were serologically very similar except for a spur formed by type E toxin. The close similarities of the two toxins suggest that toxigenic C. butyricum could arise when a wild-type strain, which is normally nontoxigenic, acquires the toxin gene of a C. botulinum type E strain.     

Vascular permeability activity of botulinum C2 toxin elicited by cooperation of two dissimilar protein components.

Botulinum C2 toxin has vascular permeability as well as lethal activities. Both activities are elicited by cooperation of two dissimilar protein components, designated components I and II, which individually have very low activities. The vascular permeability activity of C2 toxin, demonstrated as blueing response after intravenous injection of Evans blue, was markedly enhanced by treatment with trypsin and was abolished by neutralization with either anti-component I or II serum. Inflammatory reactions, such as edema, congestion, and hemorrhage, were found at the site of intradermal injection of trypsinized C2 toxin. No vascular permeability activity was demonstrated by the intradermal injection of the toxin of Clostridium botulinum types A through F. These results indicate that C2 toxin has a novel biological activity, which is not possessed by the neurotoxin elaborated by C. botulinum types A through F. This suggests that C2 toxin causes lethality in a different way from that of botulinum neurotoxin, which is known to inhibit the presynaptic release of acetylcholine at the neuromuscular junction.     

A型肉毒毒素引起人增生性瘢痕成纤维细胞的凋亡A型肉毒毒素引起人增生性瘢痕成纤维细胞的凋亡

背景：A型肉毒毒素临床上可以治疗增生性瘢痕,体外细胞培养研究发现可以抑制增生性瘢痕成纤维细胞的增殖。 目的：观察A型肉毒毒素对人增生性瘢痕成纤维细胞增殖的抑制作用,以及对人增生性瘢痕成纤维细胞凋亡的影响。 方法：通过消化法分离培养出人增生性瘢痕成纤维细胞,分别用不同浓度的A型肉毒毒素对细胞的生长增殖过程进行干预,通过MTT染色,于酶联免疫检测仪570 nm测定吸光度来研究细胞生长增殖情况,计算抑制率。通过Hoechst33342及PI染色检测人增生性瘢痕成纤维细胞凋亡情况,并计算凋亡率。 结果与结论：人增生性瘢痕成纤维细胞生长过程中呈梭形,细胞生长旺盛,细胞融合成单层,细胞排列成高度一致性。经A型肉毒毒素处理后,细胞增殖速度明显减慢,细胞数量减少,细胞排列方向散乱。MTT染色后吸光度减弱,随A型肉毒毒素浓度增加,吸光度明显减弱,与对照细胞比较,差异有显著性意义(P < 0.05),半数抑制率出现在0.4 IU/L。在荧光显微镜下,人增生性瘢痕成纤维细胞经Hoechst33342和PI染色后细胞核呈现蓝色,细胞核为光滑的圆形或椭圆形外观。A型肉毒毒素干预后细胞核致密浓缩,染色不均匀,折光性增强,核膜皱缩,部分细胞核碎裂,出现碎块,有凋亡小体出现。随着A型肉毒毒素浓度的增加细胞凋亡率逐渐增高,与对照细胞比较差异有显著性意义(P < 0.05),半数凋亡率在0.4 IU/L。说明A型肉毒毒素可以抑制人增生性瘢痕成纤维细胞的增殖,其主要通过引起细胞凋亡的途径来抑制成纤维细胞的增殖。     

Repeated stimuli for axonal growth causes motoneuron death in adult rats: the effect of botulinum toxin followed by partial denervation

Axons of motoneurons to tibialis anterior and extensor digitorum longus muscles of adult rats were induced to sprout by injecting botulinum toxin into them, by partial denervation or by a combination of the two procedures. Ten weeks later, the number of motoneurons innervating the control and operated tibialis anterior and extensor digitorum longus muscles was established by retrograde labelling with horseradish peroxidase. In the same preparations, the motoneurons were also stained with a Nissl stain (gallocyanin) to reveal motoneurons in the sciatic pool. Examination of the spinal cords from animals treated with botulinum toxin showed that the number of retrogradely labelled cells and those stained with gallocyanin in the ventral horn on the treated compared to the control side was unchanged. In rats that had their L4 spinal nerve sectioned on one side, the number of retrogradely labelled cells on the operated side was 48+/-3% (n = 5) of that present in the control unoperated ventral horn. Thus, just over half the innervation was removed by cutting the L4 spinal nerve. Counts made from gallocyanin-stained sections showed that 94+/-4% (n = 5) of motoneurons were present in the ventral horn on the operated side. Thus, section of the L4 spinal nerve did not lead to any death of motoneurons. In rats that had their muscles injected with botulinum toxin three weeks prior to partial denervation, the number of retrogradely labelled cells was reduced from 48+/-3% (n = 5) to 35+/-4% (n = 5). Moreover, only 67+/-5% (n = 5) of motoneurons stained with gallocyanin, suggesting that a proportion of motoneurons died after this combined procedure. This result was supported by experiments in which motor unit numbers in extensor digitorum longus muscles were determined by measurements of stepwise increments of force in response to stimulation of the motor nerve with increasing stimulus intensity. In partially denervated extensor digitorum longus muscles, 16.6+/-0.7 (n = 5) motor units could be identified, and in animals treated with botulinum toxin prior to partial denervation only 13.3+/-0.9 (n = 3) motor units were present. Taken together, these results show that treatment with botulinum toxin followed by partial denervation causes motoneuron death in adult rats.     

Selective isolation and rapid identification of Clostridium botulinum types A and B by toxin detection.

A simple procedure for rapid identification of Clostridium botulinum type A and B colonies from cultures and stool samples from infants with botulism was devised. The stool samples were directly streaked on C. botulinum isolation medium containing selective inhibitory agents. Typical lipase-positive colonies that appeared within 24 to 48 h were examined for the presence of botulinal toxin by the enzyme-linked immunosorbent assay and conventional mouse toxicity test. The amount of toxin associated with 48-h colonies of stock strains was comparable to that of 96-h broth culture. The quantity of toxin present in a single colony or combination of two was shown to be sufficient for toxin detection by the enzyme-linked immunosorbent assay. Of 42 additional stock strains tested in this manner, 41 (97.5%) were identified as toxigenic C. botulinum type A or B. The remaining one strain also proved to be toxigenic when it was tested as a concentrated cell suspension. This procedure should prove useful for large-scale serological screening of food and clinical specimens.     

A highly virulent canine distemper virus strain isolated from vaccinated mink in China

An outbreak of canine distemper in 2017 in mink breeding farms (Shandong province, China) caused severe pneumonia, hardened footpads, and death in more than 5000 vaccinated animals. Sequencing of the hemagglutinin and fusion protein genes from the WH2 canine distemper virus (CDV) strain we isolated from the infected minks were clustered into the recently isolated CDV Asia-1 genotype group. The WH2 strain was distinct from the current vaccine strains, containing a novel potential N-glycosylation site in its hemagglutinin protein. It also contained amino acid mutations in the fusion protein gene (I87N, T110P and L386I), and the T110P mutation results in N-glycosylation site silencing. WH2 was highly virulent in both unvaccinated and vaccinated animals in our pathogenesis experiments. Immunohistochemistry results revealed positive staining of different organs in unvaccinated and vaccinated animals. The serum in vitro neutralizing antibody titers for the vaccinated mink group and a dog were higher for the WH2 strain than those of the HNly150520B strain (isolated from a dog). These findings indicate that the current commercial vaccines provide incomplete protection against WH2 challenge infections. Thus, a new vaccine strain is urgently needed to protect against variant CDV strains.