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British Journal of Experimental... Feb 1972Acetazolamide dysmelia was induced in rat embryos by giving drug to mothers during days 9, 10 and 11 of pregnancy. With appropriate technique 100 per cent of deformed...
Acetazolamide dysmelia was induced in rat embryos by giving drug to mothers during days 9, 10 and 11 of pregnancy. With appropriate technique 100 per cent of deformed young could be produced. Individual anomalies were made up of one or more of 5 basic malformations—dislocation, reduction and supernumerary defects, syndactyly and synarthrosis. Right forepaws were invariably, left forepaws were less frequently and hindpaws were rarely involved. Most paws showed a postaxial to preaxial sequential involvement of digits, but on occasions digit 4 was more severely affected than the fifth digit. In all but 5 of 94 bilateral defects right forepaw lesions were of equal or greater severity than left forepaw lesions. The number of deformed paws and probably the severity of the paw defects were linearly related to drug dosage. Digital ray defects were accompanied by defects in the carpal bones and ulna of matching severity. During the phase of acute intoxication following drug treatment mothers lost weight and this was linearly related to the amount of drug given. The full term weight of foetuses was depressed in proportion to drug dosage but the drug displayed little if any embryolethal effect.
Topics: Abnormalities, Drug-Induced; Acetazolamide; Animals; Birth Weight; Body Weight; Carpal Bones; Female; Forelimb; Hindlimb; Injections, Intraperitoneal; Joint Dislocations; Rats; Syndactyly; Ulna
PubMed: 4335357
DOI: No ID Found -
International Journal of Medical... 2012There are a lot of reports and reviews about osteonecrosis of the talus (ONT), yet reports about the animal model of ONT to evaluate proper therapeutic approaches are...
There are a lot of reports and reviews about osteonecrosis of the talus (ONT), yet reports about the animal model of ONT to evaluate proper therapeutic approaches are rarely heard. In our study, a novel animal model was established. Pure ethanol was injected into the cancellous bone of sheep's talus. Macroscopic observation, X-ray, CT and histology were performed at two, four, 12 and 24 weeks postoperatively. It was revealed that the trabeculae of talar head began to change their structure after two weeks postoperatively compared to the normal talus. The ONT was obvious at the end of the fourth week, and their outstanding feature was the damage of trabeculae bone and formation of cavities. CT scans and pathological changes of the subjects all showed characteristics of the early stage of osteonecrosis, also the sections of the specimens confirmed necrosis of tali. By 12 weeks, the phenomenon of necrosis still existed but fibrous tissue proliferated prominently and bone reconstruction appeared in certain area. Most specimens (3/4) got late stage necrosis which presented as synarthrosis in X-ray and mass proliferation of fibrous tissue in histology at the end of 24 weeks. The novel animal model of ONT was successful, and it is inclined to deteriorate without any intervention. The study provides us a new way to evaluate various treatments on ONT in laboratory, which may eventually pave way to clinical applications.
Topics: Animals; Disease Models, Animal; Ethanol; Female; Osteonecrosis; Sheep; Talus; Tomography, X-Ray Computed
PubMed: 23136546
DOI: 10.7150/ijms.4882 -
Journal of Evolutionary Biology Apr 2012The mandibular symphyseal joint is remarkably variable across major mammalian clades, ranging in adults from unfused (amphiarthrosis) to partially fused (synarthrosis)...
The mandibular symphyseal joint is remarkably variable across major mammalian clades, ranging in adults from unfused (amphiarthrosis) to partially fused (synarthrosis) to completely ossified (synostosis). Experimental work conducted on primates suggests that greater ossification of the symphysis is a response to increased recruitment of the balancing-side (i.e. nonchewing side) jaw-adductor muscles during forceful unilateral biting and chewing, with increased fusion strengthening the symphysis against correspondingly elevated joint stresses. It is thus expected that species with diets composed primarily of foods that require high-magnitude bite forces and/or repetitive loading to process will be characterized by greater degrees of symphyseal ossification than species with relatively easy-to-process diets (i.e. food items typified by low toughness and/or low stiffness). However, comparative support for this idea is limited. We tested this hypothesis in four dietarily diverse mammalian clades characterized by variation in symphyseal fusion - the Strepsirrhini, Marsupialia, Feliformia, and Caniformia. We scored fusion in adult specimens of 292 species, assigned each to a dietary category based on literature accounts, and tested for an association between these two variables using Pagel's test for the correlated evolution of binary characters. Results indicate that greater fusion is associated with diets composed of resistant items in strepsirrhines, marsupials, and feliforms, providing some support for the hypothesis. However, no such relationship was detected in caniforms, suggesting that factors other than dietary mechanical properties influence symphyseal ossification. Future work should focus on such factors, as well as those that favour an unfused mandibular symphysis.
Topics: Animals; Biological Evolution; Bite Force; Joints; Mammals; Mandible; Phylogeny; Primates
PubMed: 22268953
DOI: 10.1111/j.1420-9101.2012.02457.x