Death Of Guinea Pigs Research Articles

The Effect of Long-Term Storage on Mycobacterium bovis.

It was established that when stored for many years (10–13 years) in low-temperature conditions (3°C), without sub-culture on a nutrient medium, Mycobacterium bovis grew as visible colonies along the line of inoculation. However, due to long-term storage in conditions of low temperature (3°C) morphology of mycobacteria differed significantly from initial cultures formed by rod-shaped bacteria. Some of them became pigment-forming and smooth on the surface. Unlike the initial strain of mycobacteria, a perennial bacteria stored under hard conditions did not cause the death of guinea pigs or their sensitization to a purified protein derivative for mammals. Morphological forms of the perennial mycobacteria had the following changes: pigment forming, L-forms of the vesicular type, non-acid-fast thread-like (filamentous) bacillary forms, and elementary bodies when compared to the initial strain. There were also some genetic changes in the target DNA due to the long-term storage of M. bovis. It may indicate a mutation in the pathogen’s DNA. These mycobacteria had altered biochemical activity during storage. The number of passages on the solid nutrient medium did not affect their fermentative activity. However, the low cultivation temperature increases mycobacterial catalase activity and the ability to hydrolyze Tween-80.

Abstract 248: Age-specific Differences in Outcomes Following Isoproterenol-induced Sudden Cardiac Death in Guinea Pigs

Background: The pathophysiological mechanisms involved in adult and pediatric heart failure (HF) are unique. One example of clinical differences in these two patient populations is the need for primary prevention implantable defibrillators (ICDs) in adults with HF, whereas pediatric HF patients infrequently have ventricular arrhythmias and rarely require ICDs. To better understand the age-specific molecular mechanisms involved in HF, we are developing a guinea pig model of pediatric HF. We have found age-specific differences in guinea pigs acutely treated with isoproterenol (ISO). Additionally, initial exposure to ISO leads to sudden death in guinea pigs. This sudden death has previously been reported as an interaction with an inhaled volatile anesthesia. We hypothesized that isoproterenol is leading to sustained ventricular arrhythmias in guinea pigs. Methods: Adult (n= 11) and young (n= 50) guinea pigs were treated with vehicle, 16 mg/kg/day or 32 mg/kg/day of ISO by osmotic pump (Alzet) implanted under isoflurane anesthesia. Cardiac rhythm was monitored in a subset via simultaneously implanted Linq recorders (Medtronic, n= 12). Results: Acute exposure to ISO in the presence or absence of isoflurane resulted in sudden death in adult and young guinea pigs. Four of the 6 adult guinea pigs exposed to ISO died even with attempts at resuscitation. In contrast, 61% (22 out of 36) of the young guinea pigs treated with ISO arrested and 60% (13 out of 22) were rescued with chest compressions. Analysis of the heart rhythms demonstrated that the guinea pigs experienced ventricular fibrillation. The arrhythmia was transient in the young guinea pigs, but sustained in the adult. Conclusions: Acute ISO leads to age-dependent differences in arrhythmias and sudden death in guinea pigs. Contrary to prior reports, this response occurs independently of isoflurane. These age-specific differences suggest unique mechanisms in calcium handling, which can lead to arrhythmias. Guinea pigs may be a useful model for the age-related differences in HF arrhythmias seen in humans. A better understanding of these differences may lead to the development of therapies to protect adult HF patients from arrhythmias.

Studies of Immunobiological Properties in <i>Francisella tularensis</i> Vaccine Strain 15 NIIEG under Extended Storage Conditions

Investigated have been 8 cultures of Francisella tularensis strain 15 NIIEG (lyophilized in 1953, 1966, 1969, 1987, 1990, 2003, 2012, and 2013, respectively) stored at the State Collection of Microorganisms of the Scientific Center on Expertise of Medical Application Products. It is established that the majority of cultures has maintained their immunobiological properties. However, it is of note that liophilization does not prevent F. tularensis strain 15 NIIEG from changes in its residual virulence under extended storage. Revealed is the fact that LD 50 for 7 cultures of tularemia microbe strain is within the limits of 100-250 microbial cells (m.c.). At the same time, residual virulence for the strain which dates back 1966 is 7.3·10 5 m.c. Immunogenic activity rates in F. tularensis 15 NIIEG strain cultures range within specified limits. Apart from this, F. tularensis 1987 strain does not comply with the established requirements to the “specific safety”, as subcutaneous inoculation with 5·10 9 m.c./ml caused death of Guinea pigs within the scheduled observation time. Demonstrated is the necessity in maintaining constant stability of the original immunobiological properties in Francisella tularensis strain 15 NIIEG under extended storage conditions.

Protective effect of taurine on cardiotoxicity of the bufadienolides derived from toad (Bufo bufo gargarizans Canto) venom in guinea-pigs in vivo and in vitro

In China, toad venom is an anti-inflammatory agent used in small doses for the treatment of various types of inflammation. Bufadienolides are cardioactive steroids responsible for the anti-inflammatory actions of toad venom. We studied the protective effect of taurine on the cardiotoxicity of bufadienolides in guinea-pigs. Bufadienolides (8 mg/kg) caused arrhythmias, cardiac dysfunction and death in guinea-pigs. Pretreatment with taurine (150, 300 mg/kg) significantly prevented bufadienolide-induced cardiotoxicity and reduced the mortality in vivo. Taurine markedly increased the cumulative doses of bufadienolides and resibufogenin required for lethal arrhythmia in ex vivo isolated guinea-pig heart. Taurine did not compromise the anti-inflammatory activity of the bufadienolides on concanavalin-A-stimulated proliferation of guinea-pig splenocytes in vitro. These data indicate that taurine can prevent bufadienolide-induced cardiotoxicity and could be a novel antidote in combination with bufadienolide therapy.

Bilirubin Attenuates Bufadienolide-Induced Ventricular Arrhythmias and Cardiac Dysfunction in Guinea-Pigs by Reducing Elevated Intracellular Na+ Levels

Bufadienolides, known ligands of the sodium pump, have been shown to inhibit the proliferation of several cancer cell types. However, their development to date as anticancer agents has been impaired by a narrow therapeutic margin resulting from their potential to induce cardiotoxicity. In the present study, we examined the effects of bilirubin, an endogenous antioxidant, on the cardiotoxicity of bufadienolides (derived from toad venom) in guinea-pigs. The results showed that bufadienolides (8mg/kg) caused ventricular arrhythmias, conduction block, cardiac dysfunction and death in guinea-pigs. Pretreatment with bilirubin (75 and 150mg/kg) significantly prevented bufadienolide-induced premature ventricular complexes, ventricular tachycardia, ventricular fibrillation and death. Bilirubin also markedly improved the inhibition of cardiac contraction in bufadienolide-treated guinea-pigs as evidenced by increases in left ventricular systolic pressure and decreases in left ventricular diastolic pressure in vivo. Furthermore, bilirubin significantly reduced the intracellular sodium content ([Na(+)]( i )) in ex vivo bufadienolide-stimulated guinea-pig ventricular myocytes loaded with the sodium indicator Sodium Green. An antitumor study showed that bilirubin did not compromise the ability of bufadienolides to inhibit gastric cancer cell MGC-803 proliferation. These results suggested that bilirubin can attenuate bufadienolide-induced arrhythmias and cardiac dysfunction in guinea-pigs by reducing elevated [Na(+)]( i ) and may improve bufadienolide therapeutic index in cancer treatment.

Abattoir survey on caseous lymphadenitis in sheep and goats in Tanta, Egypt

This study was carried out to determine some epidemiological and histopathological aspects associated with caseous lymphadenitis (CLA) on 962 slaughtered animals (692 sheep and 270 goats) at Tanta abattoir, Egypt. The prevalence of CLA among slaughtered animals was 26.92% and 25.05% on the basis of gross and bacteriological examination, respectively. On the basis of gross examination, the prevalence was 33.23% and 10.74% among slaughtered sheep and goats, respectively. Whereas on the basis of bacteriological examination, the prevalence was 32.65% and 5.55% in sheep and goats, respectively. The prevalence of CLA was significantly higher in slaughtered females than slaughtered males ( p < 0.0001; OR: 22.93; CI 95%: 15.71–33.46). Statistically, the prevalence of CLA differed among different age groups; the higher prevalence was recorded in animals of the age group over 2 years (51.35%) than those from 1 to 2 years (8.84%) ( p < 0.0001; OR: 10.98; CI 95%: 7.611–15.58) and under 1 year (7.5%) ( p < 0.0001; OR: 13.2; CI 95%: 3.944–43.00). Superficial lymph nodes of the anterior half of the body showed higher infection rate than posterior half lymph nodes. Cross section of the affected lymph nodes revealed thick caseated greenish pus surrounded by thick fibrous tissue. Histopathological examination of the affected lymph nodes showed pyogranulomas surrounded by massive infiltration of macrophages and fragmented neutrophils. The experimental injection of CLA pyogenic materials was resulted in death of guinea pigs within 7–9 days with typical gross and histological lesions of CLA. Moreover, Corynebacterium pseudotuberculosis could be isolated from the died guinea pigs. In conclusion, CLA is more prevalent in slaughtered sheep than slaughtered goats and in females than males. Also, it was observed the increase of CLA prevalence with the progress of animal age. Therefore, beside early detection and culling of infected animals, strict hygienic care during shearing process is highly recommended.

Development of therapeutics to protect the inner ear: Support from animal models.

Noise‐induced hearing loss (NIHL) is a significant clinical, social, and economic issue. Although we once thought virtually all NIHL was a consequence of mechanical damage to cells in the inner ear, we now know that intense metabolic activity drives the formation of free radicals (short‐lived, unstable, highly reactive clusters of atoms) in the inner ear. Studies in animals have clearly shown that free radicals formed during and after noise importantly contribute to NIHL, and many laboratories have demonstrated that free radical scavengers (“antioxidants”) reduce NIHL in animal subjects. Our group, including investigators at multiple institutions, has specifically shown that the combination of beta‐carotene, vitamins C and E, and magnesium is highly effective in preventing NIHL and sensory cell death in guinea pigs and mice. Use of free radical scavengers, or antioxidants, to prevent noise‐induced deficits has thus become a clinical research goal. Given the multitude of intracellular events that occur during and after noise, it is not surprising that other agents are also potentially useful therapeutic agents. Translational investigations are essential to confirm potential utility of these agents in the human inner ear.

Combined deficiency of vitamins E and C causes paralysis and death in guinea pigs

On the basis of in vitro studies, the antioxidant nutrients vitamins E and C are postulated to interact in vivo. We developed a guinea pig model to evaluate the combined deficiency of vitamins E and C in vivo. Weanling guinea pigs were fed a control diet or a vitamin E-deficient diet for 14 d, after which one-half of each group had vitamin C removed from their diet, thus creating 4 diet groups. Some animals were observed for clinical signs. Others were killed for evaluation. Of 21 guinea pigs that were observed after being fed the diet deficient in both vitamins, 8 died 9 +/- 2 d (x +/- SD) after starting the diet. Eight additional guinea pigs developed a characteristic syndrome at 11 +/- 3 d. First, they became paralyzed in the hind limbs. Within a few hours, the paralysis progressed to include all 4 limbs and caused difficulty in breathing, which would have caused death had the animals not been euthanized. Histopathologic evaluation did not identify a lesion in the muscles or nervous system that could account for the paralysis. Biochemical measurements confirmed the deficiencies and indicated that the double deficiency caused lipid peroxidation in the central nervous system. A distinct clinical syndrome of combined vitamin E and vitamin C deficiency occurs in guinea pigs. This syndrome indicates that these antioxidant vitamins are related in vivo. We speculate that acute oxidative injury in the central nervous system underlies the clinical syndrome.

Assessment of Hair Cell Death Using the Dye Extrusion Method

We examined the usefulness of the dye extrusion method for assessing cochlear hair cell death in guinea pigs. Unilateral temporal bones were incubated in sterile Dulbecco modified Eagle's medium for 1-6 h and then perfused with PBS/0.3% trypan blue to determine hair cell viability. Cells with nuclei stained with trypan blue were assumed to have died. The contralateral temporal bones of each animal were incubated with the same medium for 1-6 h and examined by transmission electron microscopy (TEM). This method revealed that hair cell viability under these conditions was maintained for at most 3 h. After incubation for more than 3 h, hair cell injury began and increased. After 6 h incubation, TEM revealed apoptotic death of outer hair cells. The results with this method agreed with the TEM findings. The dye extrusion method is simple, easy and useful for screening hair cell death in the cochlea under pathological conditions.

Purification of toxic saponins from Narthecium asiaticum Maxim.

Toxic substances in Narthecium asiaticum Maxim. were isolated and purified, monitoring the oral toxicity in guinea pigs. The crude extract prepared from the methanolic extract of the plant contained 2 major saponins (C8 and C9), and 7 corresponding saponins (C1-7) on TLC. The crude extract was fractionated by a conventional method for saponin preparation. The 1-butanol fraction was rich in C8 and C9, and showed oral toxicity. C8 and C9 were isolated by fractional precipitation and silica gel column chromatography. On the basis of C-13 and H-1 nuclear magnetic resonance (NMR) spectral data, and acid and enzymatic hydrolysis of C9, C9 was confirmed to be a mixture of two furostanol saponins (C9a, C9b); a branched trisaccharide composed of galactose, glucose, and arabinose, was linked at 3 beta-C, and glucose at 26-C of sarsasapogenin and smilagenin. C8 was considered to be a furostanol saponin containing xylose instead of arabinose in the structure of C9. Oral administration of C8 and C9 caused diarrhea, proteinuria, hematuria and death in guinea pigs.

Immunological analysis of cell-associated antigens of Bacillus anthracis.

Sera from Hartley guinea pigs vaccinated with a veterinary live spore anthrax vaccine were compared with sera from guinea pigs vaccinated with the human anthrax vaccine, which consists of aluminum hydroxide-adsorbed culture proteins of Bacillus anthracis V770-NP-1R. Sera from animals vaccinated with the spore vaccine recognized two major B. anthracis vegetative cell-associated proteins that were either not recognized or poorly recognized by sera from animals that received the human vaccine. These proteins, termed extractable antigens 1 (EA1) and 2 (EA2), have molecular masses of 91 and 62 kilodaltons, respectively. The EA1 protein appeared to be coded by chromosomal DNA, whereas the EA2 protein was only detected in strains that possessed the pXO1 toxin plasmid. Both of the extractable antigen proteins were serologically distinct from the components of anthrax edema toxin and lethal toxin. Following vaccination with the live spore vaccine, the EA1 protein was the predominant antigen recognized, as determined by electrophoretic immunotransblots. Vaccine trials with partially purified EA1 demonstrated that it neither elicits protective antibody against anthrax nor delays time to death in guinea pigs challenged intramuscularly with virulent Ames strain spores. In addition, animals vaccinated with sterile gamma-irradiated cell walls had significant antibody titers to the N-acetylglucosamine-galactose polysaccharide of B. anthracis but were neither protected nor had a delay in time to death following challenge.

The effect of oxygen-dependent antimicrobial systems on strains of Legionella pneumophila of different virulence.

Four strains of Legionella pneumophila of different virulence as identified by ability to produce pneumonia and death in guinea-pigs infected by a fine-particle aerosol were examined for factors which may intracellularly influence virulence. Possible bactericidal mechanisms possessed by alveolar phagocytes were examined. A relationship could be established between resistance to H2O2, catalase activity and virulence amongst the strains. Virulent strains resisted the bactericidal activity generated by the xanthine oxidase system; avirulent strains did not. Incorporation of various specific inhibitors of the xanthine oxidase system indicated that the main bactericidal activities were associated with the production of H2O2 and hydroxyl radicals (.OH). All strains of L. pneumophila were susceptible to the bactericidal activity generated by the myeloperoxidase-H2O2-halide system, confirming earlier observations that polymorphonuclear neutrophil leucocytes (PMNLS) are able to kill both virulent and avirulent strains of L. pneumophila.

Antihistaminic effect of terfenadine: A new piperidine‐type antihistamine

AbstractThe antihistaminic effect of terfenadine was studied in the isolated guinea pig ileum, histamine skin wheals in guinea pigs and monkeys, and i.v. histamine‐induced death in guinea pigs. In the guinea pig ileum, terfenadine, 1 × 10−7 M, shifted the histamine dose‐response curve to the right in a parallel fashion without affecting the dose‐response curve of acetylcholine and barium chloride. However, as the dose of terfenadine was increased (3.16 × 10−7 and 1 × 10−6 M) the histamine dose‐response curves were displaced to the right with a depression of the maximum response and a reduction of the slope. Thus an unsurmountable type of antagonism was observed. Acetylcholine was also antagonized in a similar fashion by these two concentrations. In contrast, terfenadine appeared to displace the barium chloride dose‐response curve to the right in a parallel fashion. At 0.4 and 0.8 mg/kg p.o., terfenadine shifted the histamine skin wheal dose‐response curves to the right in a parallel fashion, but at 1.6 to 6.4 mg/kg, terfenadine antagonized the histamine wheal dose‐response curves with a depression of the maximum and the slope of the curve. These results were also similar to those of cyproheptadine but were different from those of chlorpheniramine, which produced parallel shifts. In monkeys, terfenadine produced a substantially greater effect on the histamine wheal than did chlorpheniramine (both administered at 30 mg/kg p.o.). Terfenadine also completely protected against i.v. histamine‐induced death in guinea pigs. Terfenadine produced no atropine‐like effect against pilocarpine‐induced salivation in rabbits, no demonstrable histamine H2 antagonism, no antiserotonin activity, no α or β antagonism, and no untoward cardiovascular effects. Most significantly, terfenadine had no overt central nervous system (CNS) effects in mice, rats, guinea pigs, or monkeys; whereas chlorpheniramine produced tremors and convulsions in mice and monkeys when tested at much lower doses than those used for terfenadine. It is concluded that terfenadine is an effective and specific antihistaminic compound with the potential advantage of a lack of CNS sedative effects.

Correlation of virulence, susceptibility to leptospiricidal activity test mediated by antiserum plus complement and colonial morphology of five lines of a strain of Leptospira interrogans serovar copenhageni

Correlation of virulence, susceptibility to leptospiricidal activity test mediated by antiserum plus complement (LAT) and colonial morphology was investigated using five lines of Leptospira interrogans serovar copenhageni Shibaura. Line No. 2, a moderately virulent strain, passaged in guinea pigs for 24 successive times caused occasional death of guinea pigs. Leptospiras recovered from deceased animals were characterized by decreased susceptibility to LAT and predominance of hazy colonies upon culture. Leptospiras recovered from surviving guinea pigs were of increased susceptibility to LAT and grew predominantly in non-hazy colonies. Virulent line No. 1 subjected to passage through liquid medium for 20 successive times resulted in a slight decrease in virulence and slight increase in susceptibility to LAT, but the predominance of hazy colonies upon culture was invariable. The other three lines, Nos. 3, 4 and 5 which have been maintained for more than 10 years by passage through different media respectively, were avirulent, susceptible to LAT and produced only non-hazy colonies.

Antimicrobial Agent-Induced Diarrhea--A Bacterial Disease

Some of the earliest animal studies of antimicrobial toxicity of this type were those of penicillin in guinea pigs. DeSomer et al. [12] noted that oral or ip administration of 20,000-100,000 units of penicillin produced lethargy, failure to feed, and death in guinea pigs. The pathologic find

Coccidiosis in guinea-pigs

The attention of laboratory workers is drawn to the possibility of coccidiosis as a cause of death in guinea-pigs. The purchase of a number of guinea-pigs infected with this protozoon was followed by 12 deaths when these animals were injected with material for diagnostic purposes. No deaths occurred in the laboratory stock herd, as these were kept separate from the newcomers and were not infected. The life history of the parasite is described, together with the post-mortem findings in our series of animals.

The chemical prevention of cardiac necroses

That a healthy mind is fundamental to general well being has been recognized since prehistorictimes and proverbs analogous to “Healthy body—healthy mind” exist in many languages. Scientific inquiries with regards to mind-body interactions commenced over a century ago. Hans Selye discovered that stress activates the hypothalamus-pituitary-adrenal-thymus axis, which results in the development of the ‘general adaptation syndrome’. This syndrome is characterised by elevated resistance of stressed animals to diverse insults [1]. Andor Szentivanyi and colleagues discovered [2–4] that hypothalamic lesions prevent anaphylactic death in guinea pigs. This was the first experimental evidence for the sweeping regulatory power of the nervous system over violent, life threatening immune reactions. Miklos Jancso and coworkers [5]. described that the nervous system also controls the inflammatory response.In the seventies and eighties a handful of laboratories started to re-examine various aspects of neuroimmune-interaction. It was established that pituitary hormones have the capacity to stimulate, inhibit and modulate immune responses. Placental and pituitary hormones are also involved in the development of the immune system and maintenance of immunocompetence. It was also described that lymphoid organs are innervated and that neurotransmitters and neuropeptides are important regulators of immune and inflammatory reactions. It became gradually apparent that immune derived cytokines and nerve impulses serve as feedback signals towards the neuroendocrine system. Compelling evidence was produced, indicating that immune reactions may be conditioned in the classical pavlovian sense and that emotions affect immune function. Evidence is increasing rapidly for the physiological role of cytokines and of immunocytes in the function of various organs and tissues, and in reproduction. It is also becoming obvious that Selye's general adaptation syndrome really corresponds to the acute phase response. This is a multi-faceted and highly co-ordinated systemic defence reaction, which involves the conversion of the immune system from a specific, adaptive mode of reactivity to a rapidly amplifiable, poly-specific reaction mediated by natural immune mechanisms. Immunological (poly) specificity is assured by profoundly elevated levels of natural antibodies and liver-derived acute phase proteins.Much has been learned about the regulation of cell activation, growth and function fromimmunological studies. Burnet's clonal selectional theory designated the antigen as the sole activator [6]. Bretcher and Cohn recognised first that at least 2 signals are required [7]. This was followed by numerous studies on cell-to-cell interaction within the immune system and led to our current understanding of the importance of cell adhesion molecules and cytokines in cell activation and proliferation. This, coupled with the available information about the mechanisms of action of hormones and neurotransmitters, of signal transduction and nuclear regulatory pathways paves the way to understanding how higher organisms function in their entire complexity. It is now apparent that the Nervous-Endocrine-and Immune-Systems form a systemic regulatory network, which is capable of regulating all aspects of bodily functions in health and disease. Thus, Neuroimmune Biology provides new foundations to Biology.

Modification of early radiation death in guinea pigs.

A series of depressant and anticonvulsant drugs has been used in an attempt to modify the ‘early’ or ‘central nervous system’ death in guinea pigs. Pentobarbital given in anesthetic doses prior to irradiation dramatically alters the course of injury induced by whole body doses of 6000 r or more. Survival time is sharply increased and all signs of convulsions and hyperexcitability are suppressed. Phenobarbital and paraldehyde show similar actions, but the margin of safe dosage is smaller than with pentobarbital. The action of pentobarbital appears to be a true radiation protection. Other drugs, such as diphenyl hydantoinate suppress convulsive activity and lengthen survival time slightly. This is probably due to a sparing action from the intense muscular activity associated with the convulsions. None of the drugs tested showed an effect when given after irradiation.

Early radiation death in guinea pigs.

Early radiation death in guinea pigs.

Prophylaxis of experimental diphtheria with penicillin.

Received for publication February 21, 1951. * This work was submitted in partial fulfillment for the Master of Science Degree at the Department of Bacteriology, University of Illinois College of Medicine, Chicago, 111. Ercoli,9 in 1945, reported that a dose of penicillin delayed the death of guinea pigs infected with cultures of C. diphtheriae; also, that penicillin exerted a marked activity against systemic, mainly bacillary, infections in mice. In the same year, Young and Mood10 observed that penicillin was very active in extremely small amounts in preventing diphtheritic infections and fatal toxemia in guinea pigs. Recently, prolonged therapeutic blood levels have been obtained following a single injection of penicillinprocaine.11'12 Inhibitory levels have been maintained for as long as 4 or 5 days. The possibility of using penicillinprocaine as a prophylactic agent against diphtheritic infections suggests itself. Our results in experimental animals indicate that protection may be obtained with its use.