Experimental Pneumococcus Lobar Pneumonia in the Dog 12

Self Cite

The data derived from the above described investigations indicate that dogs do not develop hypersensitivity to the pneumococcus as the result of experimental lobar pneumonia. This inference is based on the following findings: 1. Fifteen dogs were given Type I and Type II pneumococcus lobar pneumonia and following recovery were tested for hypersensitiveness by means of intrabronchial and intracutaneous injections of the autolysate made from the homologous pneumococcus. 2. Seven dogs showed a pulmonary lesion discernible with the X-ray at site of the autolysate inoculation; three of these dogs were normal controls. 3. No evidence of a positive skin reaction was found in any of the fifteen dogs, many of which received repeated infections and intradermal autolysate injections. 4. Subsequent infections in the same animals were definitely milder than the initial infection. 5. The infections following the administration of intrapulmonary and cutaneous autolysate were practically of the same intensity as the initial infection. 6. Temperature, pulse rates, white blood counts and differential blood pictures showed no significant variations following intrapulmonary injection of autolysate. 7. Tests for the acquisition of humoral immune bodies following autolysate injection and recovery from the experimental disease showed the presence of these substances in some of the dogs and their absence in others. 8. Study of the pathology of the pulmonary lesions produced by the autolysate failed to reveal histological changes characteristic of an allergic reaction. However, the presence of perivascular accumulations of large mononuclear cells observed in the lesions of the recovered dogs does suggest a locally accelerated reactivity of the fixed tissue cells to the products of the pneumococcus.

mentioning

confidence: 63%

“…of culture suspended in a broth-starch mixture were placed directly into a terminal bronchiole of the lung by means of a No. 11 F. ureteral radio-opaque catheter with the dog under the fluoroscope (11). The animals were infected on twenty-three different occasions; three of them, Nos.…”

Section: Methodsmentioning

confidence: 99%

Tests for Pneumococcus Hypersensitiveness in Dogs After Recovery From Experimental Pneumococcus Lobar Pneumonia

Coggeshall

1935

Self Cite

“…As few as ten pneumococei kill a mouse in 24 hours, and as little as 0.00001 cc. of culture suitably placed in the lung of a dog produces lobar pneumonia (11). The organism is passed through a rabbit approximately every 6 weeks.…”

Section: Methodsmentioning

confidence: 99%

On the Nature of Bacteremia in Experimental Pneumococcal Pneumonia in the Dog

Robertson

Hamburger

Gregg

1953

Studies on bacteremia in pneumococcal lobar pneumonia have brought forward accumulating evidence to indicate that this form of pneumococcus infection in the human being is characteristically a localized disease. The older view that lobar pneumonia in its beginning stages is accompanied by a transient invasion of the blood stream is not supported by the results of blood cultures in early cases. While bacteremia may occur within the first 24 hours of the disease, the great majority of cases exhibit a sterile blood at this time (1, 2). x The marked alteration in prognosis occasioned by finding pneumococci in the blood stream at any period in the disease is so generally recognized that it is mentioned here only to emphasize the importance of this phenomenon about which so little is known. The conception that bacteremia indicates a breaking down of the body's defence mechanism is probably correct, since it has been observed that the more extensive the pulmonary involvement and the lower the white blood count the greater the likelihood of bacteremia (3), and that following the onset of baeteremia an increasing number of pneumococci in the blood is associated with a rapidly rising mortality. However, we have little information as to how or why pneumococci escape from the pulmonary lesion.Of the various factors in bodily resistance, which might operate to control the liberation of pneumococci from the lung into the blood stream, that of * Present address:

“…It might be argued that only the fluid component of an inflammatory process (47, 48) was present and was not detected histologically but, if this were so, it would support our concept concerning the effect of pulmonary fluid. In addition, it seems probable that the mechanism by which injection of irritating substances facilitates initiation of pneumococcal pneumonia (25,49,33) is by causing the fluid component of inflammation to enter the alveoli. Furthermore, the production of pneumonia in animals by injection of pneumococci alone (50) may be due to a similar reaction from the organisms themselves.…”

Section: Pulmonarymentioning

confidence: 99%

Pulmonary Edema in Influenzal Pneumonia of the Mouse and the Relation of Fluid in the Lung to the Inception of Pneumococcal Pneumonia

Harford¹,

Hara²

1950

In a preceding study (2) concerning the mechanism by which influenza viral infection of the mouse induces susceptibility to secondary pneumococ~l pneumonia evidence was presented that this susceptibility is associated with the appearance of the lesion produced by the virus. The studies reported in the present paper indicate that pulmonary edema is a component of the influenza viral lesion in the mouse and that the presence of fluid in the lung is an important factor in the inception of pneumococcal pneumonia in this animal. In addition, evidence is presented that the chief action of fluid under these circumstances is to furnish a culture medium for growth of pneumococci. Methods and MaterialsDetails of techniques have been described in earlier papers (2, 3). Mice were infected with the Weiss strain of influenza virus and the A5 strain of Type I pneumococcus. 1 The intrabronchial method of inoculation was used not only for the virus but also for introducing fluids or cultures into the lung. In addition, mice were allowed to inhale fine droplets containing pneumococci and were observed for survival or were killed and the pneumocoecal content of the left lobe of the lung determined by grinding the tissue in a mortar and preparing poured blood agar plates.Although pulmonary fluid could be seen in microscopic sections stained with hematoxylin and eosin, other staining procedures rendered fluid more easily and certainly visible. Iron hematoxylin (5) and phloxin with methylene blue (6) were used for this purpose and some undifferentiation of the latter was permitted. Pneumococci in the lung were visualized well with eosin and methylene blue (6) or Giemsa (6).Reexpansion of lungs with fixative was carried out as before in order to see the structure of the lung adequately (7). However, because of the possibility that introduction of fixative into