Age changes in conduction velocity, refractory period, number of fibers, connective tissue space and blood vessels in sciatic nerve of rats

1956 ◽  
Vol 104 (1) ◽  
pp. 1-16 ◽  
Author(s):  
James E. Birren ◽  
Patrick D. Wall
2021 ◽  
Vol 71 (3) ◽  
pp. 1066-70
Author(s):  
Ayesha Asad ◽  
Shabnam Hamid ◽  
Afnan Gul ◽  
Noreen Anwar ◽  
Dujanah Bhatti ◽  
...  

Objective: To observe inflammation of interstitial connective tissue space caused by Lead acetate in rat testis and ameliorative after math caused by Ficuscarica. Study Design: Laboratory based experimental study. Place and Duration of Study: Anatomy Department, Army Medical College Rawalpindi together with NIH (National Institute of Health) Islamabad, from Mar to Nov 2017. Methodology: Sprague Dawley male rats, 30 in quantity were chosen and 10 animals each partited into 3 groups. Treatments were given for 8 weeks, once daily. Group A was control group. Group B was treated with dosage of 30 mg/kg of Lead acetate. Group C was given dosage of 30 mg/kg of Lead acetate as well as 80 mg/kg of Ficuscarica. Twenty four hours after the concluding dose, animals were vivisected. For histological study, testis were fixed and stained with Haematoxylin and eosin. Interstitial connective tissue space thickness was morphometrically and assessed by SPSS version 22. A p-value <0.05 was considered significant in results. Results: Interstitial space thickness was significantly increased due to inflammation (>3 times normal) in group B in comparison to groups A and C. Thickness of space was slightly increased (<2 times normal) in group C in comparison to groups A due to reduction in inflammation. Conclusion: There was increased thickness of interstitium due to inflammation, cellular congestion and lymphocytic infiltration in rat’s testis because of lead acetate but concomitant dose of Ficuscarica protects against inflammation, venous congestion of interstitial space.


1934 ◽  
Vol 60 (2) ◽  
pp. 199-210 ◽  
Author(s):  
C. B. Huggins ◽  
H. R. McCarroll ◽  
A. A. Dahlberg

The formation of dentin and enamel in the abdominal wall in young pups was achieved by transplantation of the soft tissues of the developing tooth germ. An interesting finding was the cytomorphosis of the epithelium of the enamel organ. When this was transplanted so that the ameloblasts were in contact with the odontoblasts the cylindrical character of the epithelial cells was preserved and enamel was produced; otherwise the cylindrical shape of these cells was lost and a stratified epithelium resulted, resembling the gingival and certain tumors (the adamantinoma) of the jaw and related structures. This degenerated epithelium did not produce enamel and had an important characteristic of not forming cysts in a closed connective tissue space, instead forming islands and cords of cells with epithelial pearl formation. Thus the influence of mesodermic connective tissue derivatives on the form and function of epithelium is presented. The odonto-blasts were found capable of survival as such and readily formed new dentin in transplantation; the stellate cells of the pulp were inert from the standpoint of inducing calcification.


1994 ◽  
Vol 19 (4) ◽  
pp. 427-431 ◽  
Author(s):  
Hyung-Cheul Shin ◽  
Yun-Lyul Lee ◽  
Hyeok-Yil Kwon ◽  
Hyoung Jin Park ◽  
Stephen A. Raymond

1986 ◽  
Vol 55 (4) ◽  
pp. 635-643 ◽  
Author(s):  
P. Grigg ◽  
H. G. Schaible ◽  
R. F. Schmidt

Recordings were performed from sciatic nerve or dorsal root filaments in 28 cats to study single group III (conduction velocity 2.5-20 m/s) and group IV (conduction velocity less than 2.5 m/s) units supplying the knee joint via the posterior articular nerve (PAN). In seven of these cats the knee joint had been inflamed artificially. Recordings from sciatic nerve filaments revealed responses to local mechanical stimulation of the joint in only 3 of 41 group IV units and in 12 of 18 group III units from the normal joint. In the inflamed joint 14 of 36 group IV units and 24 of 36 group III units were excited with local mechanical stimulation. In recordings from dorsal root filaments (normal joint) 4 of 11 group IV units and 7 of 13 group III units were activated by stimulating the joint locally. In the normal joint four group IV units (recorded from dorsal root filaments) responded only to rotations against the resistance of the tissue, whereas the majority of the fibers did not respond even to forceful movements. Group III units with local mechanosensitivity in the normal joint reacted strongly or weakly to movements in the working range of the joint or only to movements against resistance of the tissue. In the inflamed joint, group IV fibers (recorded in sciatic nerve filaments) with detectable receptive fields responded strongly to gentle movements or only to movements against resistance of tissue. Some did not react to movements. Group III units reacted strongly or weakly to gentle movements or only to movements against resistance of the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)


1925 ◽  
Vol 8 (2) ◽  
pp. 21-31 ◽  
Author(s):  
G. H. Parker

1. Quiescent sciatic nerve of the frog discharges CO2 at the average rate of 0.00876 mg. CO2 per gram of nerve per minute. 2. Sciatic nerve steeped one minute in boiling water discharges CO2 at first at a low rate and after an hour and a half not at all. 3. Degenerated sciatic nerve discharges CO2 at a slightly higher rate than normal living nerve does. 4. Connective tissue from the frog discharges CO2 at an average rate of 0.0097 mg. per gram of tissue per minute. 5. Assuming that a nerve is composed of from one-half to one-quarter connective tissue the CO2 output from its strictly nervous components is estimated to be at a rate of 0.008 mg. CO2 per gram of nerve per minute. 6. Stimulated sciatic nerve increases the rate of its CO2 output over quiescent nerve by about 14 per cent. When this number is corrected for strictly nervous tissue the rate is about 16 per cent. 7. The increased rate of CO2 production noted on stimulation in normal sciatic nerves was not observed when they were boiled, blocked, or degenerated. It was also not observed with stimulated strands of connective tissue.


2012 ◽  
Vol 12 (3) ◽  
pp. 311-321 ◽  
Author(s):  
Dorota Wojtysiak ◽  
Katarzyna Połtowicz ◽  
Władysław Migdał

Effect of Breed and Age on Histopathological Changes in Pig M. SemimembranosusThe aim of the study was to determine the type and extent of histopathological changes in m. semimembranosus of Polish Landrace (PL), Polish Large White (PLW), Duroc, Pietrain, and Puławska pigs at 60, 90, 120, 150, 180 and 210 days of age. Changes in fibre size (atrophy, hypertrophy - giant fibres), changes in fibre shape (angular fibres), degenerative lesions (necrosis with phagocytosis) and connective tissue hypertrophy were evaluated. The presence of giant fibres was the only histopathological change observed in all age groups of PL, PLW, Duroc and Pietrain pigs, with the percentage of pigs with this type of pathology and the frequency of giant, atrophic and angular fibres increasing significantly with age. In Puławska pigs, giant fibres were only found in the oldest pigs aged 210 days. In these animals, giant fibres as well as atrophic fibres (at 180 and 210 days of age) and angular fibres (at 120, 150, 180 and 210 days of age) occurred in the smallest number of animals and were least extensive. Meanwhile, Pietrain pigs were characterized by a greater number of animals, a significantly greater proportion of giant fibres in all analysed age groups, and a greater proportion of atrophic fibres at 180 and 210 days of age compared to the other pig breeds under analysis. For connective tissue hypertrophy and necrosis with phagocytosis, the changes were not extensive. It is concluded that both the advancing age of the animals and selection of the pigs for increased leanness significantly increases the incidence of histopathological changes in muscle tissue, which may directly translate into pork quality.


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