scholarly journals STUDIES ON A PARATYPHOID INFECTION IN GUINEA PIGS

1927 ◽  
Vol 45 (2) ◽  
pp. 365-377 ◽  
Author(s):  
Theobald Smith ◽  
John B. Nelson
Keyword(s):  
Short Duration ◽  
Guinea Pigs ◽  
Natural Resistance ◽  
Causative Organism ◽  
Breeding Stock ◽  
Fecal Carriage ◽  
Endemic State

Factors bearing on the maintenance of paratyphoid in an endemic state are discussed. There was no evidence of any increase nor any dearly demonstrable proof of a decline in virulence of the causative organism. This persisted within the breeding stock and it is suggested that the sows constituted the chief focus for dissemination of the organism to their young and from these to the population at large. Evidence is presented that the carriage of B. paratyphi in the feces was of relatively short duration. Fecal carriage of B. paratyphi was commonly associated with a localization of the organism in the spleen. Since it is obvious that some factor or factors must have changed in the transition from epidemic to endemic phase in the presence of younger generations, the hypothesis is tentatively presented that the transition from epidemic to endemic phase is due to a combination of the weeding out of individuals of low natural resistance with a gradual adjustment of the invading organism to the population on a lowered level of virulence.

scholarly journals ALLERGIC IRRITABILITY

1928 ◽  
Vol 47 (3) ◽  
pp. 437-448 ◽  
Author(s):  
Paul A. Lewis ◽  
Dorothy Loomis
Keyword(s):  
Anaphylactic Reaction ◽  
Antibody Production ◽  
Guinea Pigs ◽  
Natural Resistance ◽  
Experimental Result ◽  
Second Phase ◽  
Reaction Complex

The allergic irritability of closely inbred guinea pigs as represented by their capacity to produce hemolytic antibodies for beef and sheep corpuscles, and agglutinins for Bacillus typhosus and Bacillus abortus (Bang) differs by families and therefore is at least partly dependent on inherited characteristics. These differences show an imperfect but suggestive correlation with the differences in resistance of the same families to inoculation tuberculosis as previously determined by Wright and Lewis. The differences in antibody production also show an imperfect correlation with the differences in response in the anaphylactic reaction complex as previously determined by Lewis and Loomis. These studies suggest very strongly that the allergic irritability is one of the several inheritable characters which form a partial basis for the natural resistance to tuberculosis. The antibody-producing capacity is only satisfactorily defined when minimal or moderate amounts of antigen are used and this in single treatments. The irregularities in experimental result when repeated treatments or very large single treatments are used suggest that antibody production in the second or "acquired capacity" phase may rest on a somewhat different fundamental basis than the latent or potential natural capacity. There is some very slight evidence that production in the second phase may also be influenced by inherited qualities.

scholarly journals An Analysis of the Influence of Irradiation by means of a Mercury Vapour Lamp upon the Health and Fertility of a Breeding Stock of Guinea-pigs and upon the Health of their Offspring during the First Six Weeks of Life

1930 ◽  
Vol 30 (2) ◽  
pp. 154-164 ◽  
Author(s):  
G. F. Petrie
Keyword(s):  
Guinea Pigs ◽  
Test Dose ◽  
Mercury Vapour ◽  
Tetanus Antitoxin ◽  
Breeding Stock ◽  
Mercury Vapour Lamp ◽  
Hygienic Conditions

The maintenance of a constant supply of healthy guinea-pigs is an important part of the work of laboratories which are engaged in the production of diphtheria and tetanus antitoxin. The subacute infective processes to which malnutrition predisposes enhance the effect of the test dose of toxin, with the result that irregular deaths among the animals under test render difficult the titration of the antitoxin. For this reason it is desirable that breeding stocks should be kept in suitable animal houses under the best hygienic conditions possible. This policy has been followed in the Serum Department of the Institute for many years; there have been comparatively few introductions of stock from outside sources, and within recent years special attention has been devoted to diet.

Short Duration Time Constant Associated With Chewing in the Guinea Pig

Behaviour ◽  
1995 ◽  
Vol 132 (7-8) ◽  
pp. 497-517 ◽  
Author(s):  
Louis J. Goldberg ◽  
Geoffrey E. Gerstner
Keyword(s):  
Guinea Pig ◽  
Detailed Analysis ◽  
Short Duration ◽  
Time Constant ◽  
Guinea Pigs ◽  
Mammalian Species ◽  
Movement Patterns ◽  
Laboratory Animals ◽  
Temporal Perception ◽  
Oscillatory Mechanism

AbstractPrevious investigations have reported a time constant on the order of a few seconds associated with temporal perception in humans, and with movement patterns in humans and other mammalian species. It has been suggested that the time constant represents the operation of a physiological oscillatory mechanism that is common among many mammalian species. However, the time constant has not yet been observed in laboratory animals; therefore, there is no laboratory-based behavior paradigm upon which studies into the physiological nature of this time constant can be based. Because of our familiarity with guinea pig feeding, the current study was undertaken in order to find evidence of the time constant in feeding-associated activities of guinea pigs. Eleven guinea pigs were starved for a 24 hr period, then placed individually into a rich behavioral arena for 30 min, during which time they were videotaped continuously while they roamed freely. The animals inevitably ate during these videotape sessions, and a detailed analysis of chewing parameters was done. It was found that chewing typically occurs in bursts, and that the median burst duration was 1.03 - 3.46 s for individual animals. Chewing burst durations were similar to the durations of many movement patterns in other species including humans. This provides further support for the hypothesis that there is a highly conserved time constant associated with movement patterns in mammals. It is believed that guinea pig chewing bursts provide a convenient laboratory based model for elucidating the neuro-physiologic mechanisms of this time constant.

scholarly journals THE QUANTITY OF CHOLESTEROL IN THE BLOOD SERUM OF THE GUINEA PIG AS AN INHERITED CHARACTER; ITS RELATION TO NATURAL RESISTANCE TO TUBERCULOSIS, AND TO TUBERCULOSIS INFECTION

1927 ◽  
Vol 45 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Richard E. Shope
Keyword(s):  
Guinea Pig ◽  
Blood Serum ◽  
Serum Cholesterol ◽  
Guinea Pigs ◽  
Direct Relationship ◽  
Cholesterol Content ◽  
Tuberculosis Infection ◽  
Natural Resistance ◽  
Bovine Type

1. Infection with tubercle bacilli of bovine type produced no alteration in the serum cholesterol content in guinea pigs. 2. Certain controlled variations in diet produced no changes in the serum cholesterol content in guinea pigs. 3. Inbred families of guinea pigs known to manifest differing resistances to tuberculosis gave differing serum cholesterol values, but no direct relationship between the two sets of phenomena could be established. 4. It seems probable that in the guinea pig the cholesterol content of the blood serum is influenced by inherited factors.

Properties of Calcium Spikes Revealed During GABAA Receptor Antagonism in Hippocampal CA1 Neurons From Guinea Pigs

1997 ◽  
Vol 78 (5) ◽  
pp. 2269-2279 ◽  
Author(s):  
Masami Miura ◽  
Masatomo Yoshioka ◽  
Hiroyoshi Miyakawa ◽  
Hiroshi Kato ◽  
Ken-Ichi Ito
Keyword(s):  
Short Duration ◽  
Guinea Pigs ◽  
Channel Blocker ◽  
Receptor Antagonists ◽  
Receptor Antagonism ◽  
Calcium Spikes ◽  
Ca1 Neurons ◽  
Synaptic Inputs ◽  
Hippocampal Ca1 Neurons ◽  
Hippocampal Ca1

Miura, Masami, Masatomo Yoshioka, Hiroyoshi Miyakawa, Hiroshi Kato, and Ken-Ichi Ito. Properties of calcium spikes revealed during GABAA receptor antagonism in hippocampal CA1 neurons from guinea pigs. J. Neurophysiol. 78: 2269–2279, 1997. Intracellular electrical responses and changes in intracellular calcium concentration ([Ca2+]i) in response to activation of synaptic inputs and to DC injections were recorded simultaneously from CA1 pyramidal neurons ( n = 42) in guinea pig hippocampal slices. In the presence of the γ-aminobutyric acid-A (GABAA) receptor antagonists, bicuculline (25 μM) and picrotoxin (10 μM), broad (>20 ms) all-or-none spikes were induced by activation of synaptic inputs (20 pulses, 30 Hz) and were accompanied by a simultaneous rapid and large rise in [Ca2+]i (34 of 34 cells). By contrast, direct depolarizing current (0.7 nA, 1 s) induced spikes having short duration, during which time the spike firing pattern was observed not to be significantly affected. When Na+ channels were blocked by QX-314 applied intracellularly through the recording microelectrode in the presence of GABAA receptor antagonists, broad spikes were frequently generated by activation of synaptic inputs (32 of 33 cells). These broad spikes were blocked by Cd2+ (200 μM) or in Ca2+-free medium (6 of 6 cells) but were resistant to either tetrodotoxin (TTX; 1 μM; 6 of 6 cells) or QX-314, whereas short-duration spikes were blocked by both TTX andQX-314. Based on these findings we conclude that broad and short-duration spikes are Ca2+ and Na+ spikes, respectively. To investigate the properties of the Ca2+ spikes, antagonists of a voltage-operated Ca2+ channel were applied to the evoked responses. Nifedipine (30 μM), a L-type Ca2+ channel blocker, suppressed the generation of Ca2+ spikes, whereas Ni2+ (100 μM), theT- and R-type Ca2+ channel blocker, and ω-agatoxin-IVA (ω-Aga-IVA, 60 nM), a P-type Ca2+ channel blocker, had little effect on the generation of Ca2+ spikes. Nifedipine suppressed the rise in [Ca2+]i induced by synaptic inputs up to 26% of the control in the soma and 18–32% in the dendrites ( n = 5), respectively, whereas Ni2+ suppressed the rise by 12–27% ( n = 5) in both soma and dendrites. ω-Aga-IVA showed little effect (less than a 10% change; n = 7). These results suggest that the GABAA inhibitory system tonically suppresses dendritic Ca2+ spikes, and the L-type Ca2+ channel plays a major role in the generation of Ca2+ spikes and in Ca2+ influx.

scholarly journals EXPERIMENTAL EPIDEMIOLOGY OF TUBERCULOSIS

1930 ◽  
Vol 51 (5) ◽  
pp. 743-751 ◽  
Author(s):  
Max B. Lurie
Keyword(s):  
Respiratory Tract ◽  
Guinea Pigs ◽  
Large Percentage ◽  
Natural Resistance ◽  
Acquired Immunity ◽  
Continuous Exposure ◽  
Cavity Formation ◽  
Tubercle Bacillus ◽  
Route Of Infection ◽  
Chronic Course

1. Guinea pigs living in the same room but not in the same cage with tuberculous animals acquire tuberculosis, characterized by a chronic course, a marked involvement of the lungs, often with cavity formation and a massive tuberculosis of the tracheobronchial nodes; the mesenteric and cervical nodes are slightly or not at all affected. 2. The route of infection in these guinea pigs is almost always the respiratory tract. 3. Of 103 guinea pigs exposed for a period of up to 32 months 15 or 14.5 per cent developed tuberculosis. The shortest period of exposure leading to fatal tuberculosis was 8 months. 4. The incidence of this tuberculosis acquired by air-borne contagion increases with the duration and intensity of the exposure up to a certain point. 5. A large percentage of the guinea pigs weathered a continuous exposure to the tubercle bacillus for 32 months without becoming tuberculous. This may be due to an innate natural resistance against tuberculosis, or to an acquired immunity resulting from the continuous exposure to the contagion.

scholarly journals Effect of Colchicine on pre-Implantation Blastocysts and Io-Day-Old Embryos of the Golden Hamster

1972 ◽  
Vol 25 (5) ◽  
pp. 1105
Author(s):  
M Sohrab
Keyword(s):  
Body Weight ◽  
Effective Dose ◽  
Golden Hamster ◽  
Guinea Pigs ◽  
Natural Resistance ◽  
Normal Number ◽  
Lethal Level ◽  
Normal Ratio ◽  
Effective Doses

Orsini and Panski (1952) used colchicine in their investigations on the pro-liferative growth of hamster tissue. They found that injected doses of colchicine varying from O� 1 up to 2 mg per 100 g body weight did not cause any significant v4riation from the normal number of mitoses, and the presence of anaphase and telo-phase stages with normal spindles in normal ratio suggested that these doses were ineffective. They stated that effective doses in other rodents (mice, rats, guinea-pigs, and rabbits) are usually below the lethal level. In an attempt to establish the effective dose, they injected colchicine intraperitoneally at concentrations ranging from 0�13 to 7 mg per 100 g body weight into a series of hamsters, rats, mice, and a rabbit. At these levels colchicine was lethal for the latter three series of animals, but was not lethal for hamsters, even up to a concentration of 10 mg per 100 g body weight. They concluded that the hamster possesses a natural resistance to this compound.

scholarly journals Pseudomonas aeruginosa Biofilm Formation and Its Control

Biologics ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 312-336
Author(s):  
Aishwarya Vetrivel ◽  
Monica Ramasamy ◽  
Preethi Vetrivel ◽  
Santhi Natchimuthu ◽  
Shobana Arunachalam ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Treatment Options ◽  
Treatment Strategies ◽  
Natural Resistance ◽  
Causative Organism ◽  
Chronic Infections ◽  
Persistent Infections ◽  
Inappropriate Treatment ◽  
Conventional Antibiotics

Microbes are hardly seen as planktonic species and are most commonly found as biofilm communities in cases of chronic infections. Biofilms are regarded as a biological condition, where a large group of microorganisms gets adhered to a biotic or abiotic surface. In this context, Pseudomonas aeruginosa, a Gram-negative nosocomial pathogen is the main causative organism responsible for life-threatening and persistent infections in individuals affected with cystic fibrosis and other lung ailments. The bacteria can form a strong biofilm structure when it adheres to a surface suitable for the development of a biofilm matrix. These bacterial biofilms pose higher natural resistance to conventional antibiotic therapy due to their multiple tolerance mechanisms. This prevailing condition has led to an increasing rate of treatment failures associated with P. aeruginosa biofilm infections. A better understanding of the effect of a diverse group of antibiotics on established biofilms would be necessary to avoid inappropriate treatment strategies. Hence, the search for other alternative strategies as effective biofilm treatment options has become a growing area of research. The current review aims to give an overview of the mechanisms governing biofilm formation and the different strategies employed so far in the control of biofilm infections caused by P. aeruginosa. Moreover, this review can also help researchers to search for new antibiofilm agents to tackle the effect of biofilm infections that are currently imprudent to conventional antibiotics.

scholarly journals Feeding and breeding of laboratory animals: VIII. Breeding of guinea-pigs

1948 ◽  
Vol 46 (4) ◽  
pp. 434-437 ◽  
Author(s):  
H. M. Bruce ◽  
A. S. Parkes
Keyword(s):  
Experimental Work ◽  
Mass Production ◽  
Guinea Pigs ◽  
Post Partum ◽  
Individual Performance ◽  
Laboratory Animals ◽  
High Grade ◽  
Breeding Stock

Guinea-pigs are usually mated in permanent polygamous groups, one or more males with a large number of females, the young being harvested when ready to wean. This system is economical of labour, and is efficient in allowing of mating at post-partum oestrus and therefore of maximum reproductivity. There are, however, serious disadvantages; it is difficult to keep track of individual performance and difficult therefore to eliminate unproductive sows, the ancestry and exact age of the young are often unknown, and the conditions of rearing young among a crowd of adults are probably not ideal. These considerations suggest that, given high-grade breeding stock, the polygamous system is adequate, and probably inevitable, for the mass production of young for experimental purposes, but that it leaves much to be desired for the production of breeding stock. The obvious solution of this difficulty is to maintain a large polygamous and anonymous colony for mass breeding, and, quite separately, a small closely recorded colony to supply the breeding animals. A goodsow should produce at least 10 young per year in a life of 2 years. A demand of 10,000 animals per year, for experimental work, therefore requires a mass-breeding stock of 1000 sows, an annual replacement of 500 sows and a stock-breeding stock of 100 sows. According to our experience, about 2 hr. daily on the part of a trained technician would be required to maintain close recording of such a pilot stock and of its progeny to puberty (Bruce & Parkes, 1947b).

scholarly journals Epizootic among Veld Rodents in De Aar and Neighbouring Districts of the Northern Cape Province

1930 ◽  
Vol 29 (4) ◽  
pp. 394-414 ◽  
Author(s):  
J. A. Mitchell
Keyword(s):  
Guinea Pigs ◽  
Similar Condition ◽  
Cape Town ◽  
Considerable Degree ◽  
Considerable Proportion ◽  
Causative Organism ◽  
Undescribed Species ◽  
Highly Pathogenic ◽  
Haemorrhagic Septicaemia ◽  
Northern Cape

1. During the summer months 1928–9 an epizootic occurred in De Aar and neighbouring districts among small veld rodents, mainly affecting Namaqua gerbilles (Desmodillus auricularis).2. Many of the animals dying showed a haemorrhagic septicaemia, the causative organism of which appeared to be a Pasteurella rather smaller in size than Pasteurella (Bacillus) pestis.3. In a considerable proportion of the animals found dead there was no obvious septicaemia.4. A description is given of the Pasteurella, which is believed to be a hitherto undescribed species, and for which the name Pasteurella desmodilli is suggested.5. This organism was found to be highly pathogenic for rabbits, less so for guinea-pigs and mice, and non-pathogenic for rats and fowls.6. It was found by Rhodes to be highly pathogenic for Lobengula gerbilles (Tatera lobengulae) from Cape Town, but for animals of this species from Johannesburg it proved to be much less virulent, and even when it killed them there was frequently no septicaemia.7. The above observation seems to indicate the presence of a considerable degree of immunity among the Johannesburg lobengulas, as compared with those from Cape Town.8. It is suggested that a similar condition of partial immunity among the Namaqua gerbilles (for which there is other evidence adduced) might account for the finding of many of them dead without obvious septicaemia.9. The existence of this disease introduces a complication in the diagnosis of plague among veld rodents.

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