Histomorphometric Assesment of Fracture Healing in Contaminated Segmental Fracture after Sterilization using Microwave Irradiation: An experimental study on Wistar rats

PURPOSE: To analyze the effects of sodium hyaluronate and carboxymethylcellulose membrane on collagen and fibroblast formation in bowel suture healing in rats. METHODS: 48 male Wistar rats, weighing 250 to 343g, were randomized into two groups: group I - bowel suture without applying a biologically absorbable membrane and group II - bowel suture with application of an absorbable membrane. The two groups were divided into subgroups of 3, 14 and 30 days of observation, with 8 rats in each subgroup. All were sacrificed after the end of the observation period. RESULTS: No morbidity or mortality was observed during the experiment. The amounts of collagen in group I were 23.4%, 72.1% and 67.6% and in group II were 22.5%, 52.5% and 51.6%, for the subgroups of 3, 14 and 30 days, respectively. Comparison between groups showed that the 14-day (p=0.0013) and 30-day (p=0.0587) subgroups had significant variance, with larger collagen zones in animals in which the membrane was not applied. However, with regard to fibroblasts, group I had 2%, 13% and 8% and group II had 2%, 10% and 8%, for the 3-day (p=1.0), 14-day (p=0.3184) and 30-day (p=0.5995) subgroups, respectively, showing no significant variance. CONCLUSION: The use of the biologically absorbable membrane cause a decrease in collagen formation, while not altering the number of fibroblasts, in bowel suture healing in rats, without increased morbidity and mortality.

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Strain Differences Occurring in an Experimental Study of Punishment

Psychological Reports ◽

10.2466/pr0.1965.16.2.531 ◽

1965 ◽

Vol 16 (2) ◽

pp. 531-536 ◽

Cited By ~ 3

Author(s):

Morton H. Kleban

Keyword(s):

Experimental Study ◽

Empirical Evidence ◽

Wistar Rats ◽

Strain Differences ◽

Training Procedure ◽

Sprague Dawley ◽

Sprague Dawley Rats ◽

Y Maze ◽

Minimum Number ◽

The Difference

Forty-three Sprague-Dawley and 43 Wistar rats were given reward training for 40 trials in a Y-maze. On the next 20 trials, control groups were continued under the same training procedure, and 50% shock trials were introduced in the training of the remaining rats. For the extinction training, the reward was shifted to the opposite arm and 50% shock was continued for the no-delay and 30-sec. delay shock groups. The most significant results were that in the 30-sec. delay groups, the delay helped the Sprague-Dawley rats reverse in a minimum number of trials, whereas the Wistar rats showed strong indications of response stereotypy. The findings with respect to the Sprague-Dawley rats supported the empirical evidence on the effectiveness of delay in overcoming response persistence and the findings on the Wistar rats supported the empirical evidence on omission in punishment. The difference in response to punishment between the two albino strains emphasizes the need for experimental study of strain factors. Experiments should be repeated with several animal strains to remedy over-generalization from single strains and to help elaborate our understanding of the interaction present between punishment and strains.

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