Biomedical subjects

J Dörfl

Publications and source records attributed to J Dörfl.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Selective breeding for variations in patterns of mystacial vibrissae of mice. Bilaterally symmetrical strains derived from ICR stock.

The establishment of certain patterns of mystacial vibrissae in mice has been the aim of an extensive breeding program carried on in this laboratory since 1977. In a companion paper we have reported on variations in this pattern in an outbred population of ICR mice. Starting with 21 ICR animals we bred, mostly by brother-sister mating, for 13 bilaterally symmetric patterns of mystacial vibrissae characterized by the presence (or absence) of supernumerary whiskers (SWs). The strains are classified as follows: I, a mouse strain with the standard pattern; II, eight strains bred for the occurrence of SWs at a given site or sites; and III, four mouse strains bred for a maximal number of SWs in different regions of the whiskerpad. Commonly, SWs occur in regions that coincide with the zones of mergence between the three facial processes except for two class II strains in which we bred for SWs in the "straddler" row of vibrissae, and for one class III strain, in which we cultivated the tendency (that appeared late in our program) to have SWs at the crest of a facial process. For classes I and II we analyzed the results for about 18 generations in terms of "improvement," meaning an increase in the percentages of animals with the desired phenotype together with a decreased frequency of undesired SWs. For class III, success in breeding meant the increase of the mean number of the desired SWs. All results led to the same conclusion: there is a genetic basis for the occurrence of SWs. The side preference of a particular SW is not strain dependent. It disappears in those class I and II strains in which almost 100% of animals obtained the desired phenotype. The increase in number of SWs in one zone of mergence does not depend on the presence of SWs in the other. Where tested, we almost always found a representation of an SW in a topologically equivalent location within the "barrelfield" area of the somatosensory cerebral cortex. Except for some diseases early in the breeding program, and some side effects of inbreeding that were eliminated, the population was without obvious defects. Where tested, there was no correlation between the occurrence of SWs and sex. The observed variations in pattern of mystacial vibrissae and their genetic background led us to propose a morphogenetic model for the formation of the pattern of mystacial vibrissae.

Animals↗

PubMedDate not supplied

Variation in pattern of mystacial vibrissae in mice. A quantitative study of ICR stock and several inbred strains.

We report on the variation in the pattern of mystacial vibrissae in ICR mice, of which one-half of the about 600 animals investigated showed one or more supernumerary whiskers (SWs). The SWs and their follicles--in all respects identical to the units of the standard pattern except for their smaller size--occurred at a restricted number of sites. In addition, a limited number of mice from two BALB/c strains were analyzed. Half of them also had one or more SWs, but mainly at one site. Mice of the C3H/HeJ and DBA/2J(a) strains were virtually without SWs, whereas animals from the NMRI strain were standard without exception. Nearly all animals of the C57BL/6J strain lacked between 1 and 4 vibrissae, always from one or two of the same adjacent sites. There was a slight overall predominance for the left side of the face to bear SWs and there was no clear-cut association with sex; the entire population was without obvious defects. The sites where extra or lacking whiskers occur are associated with the lines of fusion between the medial and the lateral nasal fold, and between the latter and the maxillary arch. Where tested, we always found a topologic equivalency between the pattern of the whisker follicles and the contralateral pattern of the "barrels"--multineuronal units in layer IV of the parietal cerebral cortex--whether the pattern was standard, "enriched," or lacking in elements. The data presented in this paper provided a basis for several studies carried out subsequently on animals that are the offspring of those characterized here, studies suggesting that the occurrence of supernumerary and of lacking whiskers has a genetic basis.

Animals↗

PubMedDate not supplied

Observations on surgical anatomy for rectal cancer surgery.

BACKGROUND/AIMS: The investigators studied the surgical anatomy of the main structures involved in the mobilization of the rectum (Denonvilliers' fascia, mesorectum, middle rectal artery, superior and inferior hypogastric plexuses). METHODOLOGY: The study was carried out on 20 cadavers (17 unembalmed and 3 embalmed). To study Denonvilliers' fascia, ten embryos and fetuses (11 mm to 80 mm CRL) were also examined. RESULTS: Denonvilliers' fascia originates from the fusion of the primary pouch of Douglas. The two leaves making up this structure are easily separated. The mesorectum surrounds the rectum on three sides; it is easily separated from the presacral fascia and its connective tissue is bordered by a thin membrane. The middle rectal artery varies in appearance rate, origin, size, distribution and anastomosis. It runs under the lateral ligament and also sends branches to the genital apparatus. Of the two hypogastric plexuses, the inferior is the most difficult one to identify. Its superior branches extend to the rectum, and the inferior ones to the genital apparatus. Because the anterior part contains the parasympathetic nerves and the middle rectal artery, this region is at major risk during surgical dissection. CONCLUSIONS: A sound understanding of the surgical anatomy of the rectum enables the surgeon to perform a more correct and reasonable procedure in terms of both the extent of surgical treatment and the preservation of important anatomical structures.

Adolescent↗