Architectural and histochemical analysis of the semitendinousus muscle in mice,rats, guinea pigs,and rabbits

The architectural and histochemical properties of the anatomically distinct compartments of the semitendinosus muscle (ST) of mice, rats, guinea pigs, and rabbits show that the ST is composed of two separate compartments aligned in series—a destal compartment (STd) and a proximal one (STp). The STp is further subdivided into a ventral head (STpv) and a dorsal head (STpd). The muscle fibers were arranged in parallel to the line of muscle pull within each compartment. The STd has the longest and the STpv the shortest fibers in all species. The physiological cross-sectional area and the estimated tetanic tension was greatest in the STd. Based on the staining pattern for myosin ATPase (alkaline preincubation) and an oxidative indicator (NADH or SDH), the STpv has the highest percentage of slow-oxidative (SO) or SO plus fast-oxidative-glycolytic (FOG) fibers of any portion of the muscle. The differences in fiber-type distributions and architectural designs of the separate compartments suggest a specialization of function of the individual compartments.     

Comparison of tracheal mucous transport in rats, guinea pigs, rabbits, and dogs

Tracheal mucous transport was measured using similar techniques in several species. One- to 10-microliter quantities of 99mTc-macroaggregated albumin (99mTc-MAA) were instilled via oral intubation in the distal trachea of rats, rabbits, and dogs. Tracheostomies were used for the instillation in guinea pigs. All animals were anesthetized with halothane for the instillation and allowed to recover immediately in restrainers. Clearance of the 99mTc-MAA in rats and guinea pigs was measured by a slit-collimated NaI scanner. In rabbits and dogs a series of gamma-camera scintiphotos were taken. Clearance was faster and more efficient in dogs than in the other species. No significant differences existed among the rats, rabbits, and guinea pigs in the percentages of the originally deposited material remaining at the instillation site after 1 h (P greater than 0.2). Mean values and standard deviations were 83 +/- 23%, 81 +/- 22% and 70 +/- 20% for rats, guinea pigs, and rabbits, respectively. However, in the dogs a mean of 14 +/- 12% remained at the original site of deposition after only 25 min indicating much more rapid clearance. Mean leading-edge velocities were 9.8 +/- 2.1 (SD) for dogs, 3.2 +/- 1.1 for rabbits, 2.7 +/- 1.4 for guinea pigs, and 1.9 +/- 0.7 mm/min for rats. Clearance patterns qualitatively among the species. In dogs the material moved as a few discrete boluses, whereas in the other species the activity spread toward the larynx. The relatively slow mucous transport of rats, rabbits, and guinea pigs could have important implications in inhalation toxicological studies.     

Luminal mucin in the large intestine of mice,rats and guinea pigs

Summary The luminal and epithelial mucin was studied histochemically in the large intestine of mice (Mus musculus), rats (Rattus rattus) and guinea pigs (Cavia porcellus) using freeze-substitution and vapor-fixation methods. Neutral mucin decreased and acid mucin increased in the epithelium from the cecum to the distal colon. Vacuolated cells contained more acid mucin than goblet cells. Luminal mucin always contained neutral mucin, which formed the main constituents in the cecum and in the proximal colon. Sialo-mucin increased from the cecum to the distal colon. Sulfo-mucin appeared only in the distal colon. Except in the cecum a luminal mucin layer (LML) was found at the epithelial surface. In the proximal colon LML was not entirely continuous and varied in composition and thickness (182.4 ± 170.1, 150.5 ± 110.4, 30.0 ± 28.9 (m), in mice, rats and guinea pigs, respectively), and contained many bacteria. In the distal colon LML was compact, homogeneous and thin (33.6 ± 18.8, 16.1 ± 7.3, 29.1 ± 20.0 (m), in mice, rats and guinea pigs, respectively) containing few bacteria. Possible functions of the luminal mucin and their regional differentiations were discussed.Supported by a grant from Deutsche Forschungsgemeinschaft (En 65/9). A preliminary part of this study was presented at 5th ISRP (September 1979), Clermond-Ferrand, France. Authors thank Miss G. Becker for her technical assistance     

Histochemical changes of substance P, FRAP, serotonin and succinic dehydrogenase in the spinal cord of rats with adjuvant arthritis

Various histochemical changes were found in spinal segments L4-L5 of rats with adjuvant arthritis, predominantly 30 days after inoculation. A slight to marked increase of substance P immunoreactivity occurred in laminae I, II and X. FRAP activity was enhanced in lamina II. Serotonin immunoreactivity was heavier in laminae I, VIII and IX in a few animals. The intensity of the histoenzymological reaction for succinic dehydrogenase increased in certain laminae VIII and X neurons. At day 15 of the disease the increase of substance P and FRAP activities was chiefly restricted to the medial portion of the superficial dorsal horn. There was a significant positive correlation between the scratching behaviour of arthritic rats and the substance P immunoreactivity in laminae X and I. If one accepts that scratching is pain-related, the data are consistent with a possible role of substance P in the chronic pain associated with adjuvant arthritis. They leave undetermined the significance of the other histochemical changes.     

Pathogenesis of CAR bacillus in rabbits, guinea pigs, Syrian hamsters, and mice.

Cilia-associated respiratory (CAR) bacillus isolated from infected mice (designated, CBM) and propagated in embryonated chicken eggs was inoculated intranasally in rabbits (Oryctolagus cuniculus), guinea pigs (Cavia porcellus), hamsters (Mesocricetus auratus) and mice (Mus musculus). Gross and microscopic lesions, localization of CBM antigen in the respiratory tract, development of antibody, and ability to reisolate the CAR bacillus were studied in animals killed at 2-, 4-, or 8-week intervals postinoculation (PI). In rabbits, although no histopathological changes were observed in the respiratory tract, CBM antigen was detected on the ciliated epithelium of the respiratory tract, and serum CBM antibody was also detected 4 and 8 weeks PI. In guinea pigs, no histopathological changes were noted, CBM antigen was detected in the respiratory tract 2 and 4 weeks PI but not 8 weeks PI, and serum CBM antibody was detected 4 and 8 weeks PI. In hamsters, mononuclear cell proliferation in the submucosa of the bronchus and trachea was observed 8 weeks PI. CBM antigen was detected at first in the nasal cavity 2 weeks PI and in the lower respiratory tract 4 and 8 weeks PI and serum CBM antibody was detected 4 and 8 weeks PI. In mice, histopathological changes, CBM antigen and CBM antibody were observed. CBM was reisolated from the tracheal washouts of hamsters and mice 8 weeks PI but not from those of rabbits and guinea pigs. These results confirm and extend previous reports of experimentally-induced CAR bacillus infection in mice, guinea pigs, and rabbits. To this list of susceptible laboratory animals, we now add hamsters.(ABSTRACT TRUNCATED AT 250 WORDS)