Functional and developmental morphology最新文献

The embryotoxic properties of pyrrolizidine alkaloids senecionine (water insoluble) and senecionine-N-oxide (water soluble) were examined using the CHEST method (Chick Embryotoxicity Screening Test). The beginning of the embryotoxicity range for senecionine was found to be between 3-30 micrograms; senecionine-N-oxide, on the other hand, showed no effect even with 100 micrograms dose. On the basis of the theoretical calculation, it can be expected that senecionine embryotoxicity for mammals ranges between 10-100 mg/kg maternal body weight, overlapping in this way the known adult toxicity range. The rat LD50 of most alkaloids known to be significant for human health are in the range of 34-300 mg/kg.

Four-day administration of actinomycin D to the albino rat in daily doses of 25 micrograms/kg decreased--in relation to all blood cells of the bone marrow--the values of the more mature stages of the megakaryocytic line, i.e. megakaryocytes and naked megakaryocyte nuclei. The number of megakaryoblasts was not influenced.

This paper demonstrates the structure and development of the layer of mm. flexores breves profundi in Felis catus (Carnivora). By microdissections of the deep palmar musculature, it was found that there were formed two muscle layers: 1) four muscles beginning on the palmar side of the carpus, passing distally through the intermetacarpal spaces and inserting into the dorsal digital aponeurosis of the second to fourth digit--the superficial muscle layer of mm. flexores breves profundi; 2) four muscles beginning on the palmar area of the second to fifth metacarpus and inserting into the capsules of the metacarpophalangeal joints of the second to fifth digit--the deep muscle layer of mm. flexores breves profundi. Ontogenesis of these muscle layers was studied on 35 histological series of embryonal extremities. In early ontogenesis we found a coherent cell condensate of the anlage of mm. flexores breves profundi layer. Differentiation of the anlagen of individual muscles takes place in the foetuses of 17-20 mm crown-rump length. In embryos of 17-19 mm crown-rump length a small cell condensations corresponding to the layer of mm. intermetacarpales anlagen were found in the second and third intermetacarpal spaces. Both anlagen are formed only temporarily whereafter they break into fragments and extinct.

A surface map of the paired pedal ganglia of Eremina ehrenbergi has been constructed. The pedal ganglia contain large (phi < 80 microns), middle (phi 40-60 microns) and small (phi 15-30 microns) sized neurones. Most of the somata are ipsilateral to their nerves, but there are few cases in which contralateral neurones were observed. The neurones in a ganglion send their axons primarily to the nerves originating from the ganglion, but they have also connections with neurones in other central ganglia.

Using the Chick Embrotoxicity Screening Test (CHEST), two samples of bilirubin of different commercial origin were tested on 2, 3 and 4- day old chick embryos. Water soluble Bilirubin Lachema (containing 20 mg albumin per 1 ml) had no teratogenic effect. On the opposite, Bilirubin Merck (containing 8 mg albumin per 1 ml) manifested an apparent teratogenic potential when single doses 0.2 and 0.6 micrograms were administered intraamniotically on day 4. Dose-dependent malformations of brain and eyes, cleft beak and reduction deformities of limbs were observed. No such effects could be produced by administration of Bilirubin Merck on either day 2 and 3. A tentative explanation of the difference between teratogenic properties of Merck and Lachema bilirubin preparations may be sougth in the different proportion of the free and albumin bound fractions.

The linear marking method was employed to study morphogenetic movements of tissues involved in the development of the definitive position and shaping of the shoulder and arm. Chick embryos in the range of embryonal day 3.5 to 4.5 were used with the following results: -Asymmetrical growth of the early wing bud and the oblique position of humerus anlage in the early wing bud as proposed by Saunders (1948) and Seichert (1965) were confirmed. -It was found that the cranial ascend of the shoulder (Seichert and Knospe 1992) is accompanied by the slight ventromedial rotation of the complex consisting of the scapula and coracoid. -Torsion along the longitudinal axis of the stylopodium was observed: the proximal part of the stylopodium (both the humerus anlage and related soft tissues) moves in the sense of supination, the distal part moves in the sense of pronation.

"Anatrecon" is an original Czech software package. It enables one to make easy three-dimensional reconstructions from serial sections of cells and tissues. It offers very acceptable information on the three-dimensional structure and especially on mutual relationships of biological objects in such cases when other methodical approaches, e.g., scanning electron microscopy or laser scanning confocal light microscopy, cannot be applied. The program runs on a standard IBM compatible personal computer supplemented with a digitizing tablet. The author describes the program in detail and presents examples of reconstructions of dendritic spine and nucleus of nerve cell.

Effects of oxacillin administered to pregnant or nursing randombred NMRI mice on the humoral immune response of their offspring were studied. The primary humoral response of male offspring to immunization by sheep red blood cells (SRBC) on the 24th postnatal day was assayed. Spectrophotometric determination of SRBC lysis by anti-SRBC IgM antibodies produced by spleen cells was used. Treatment of pregnant mice with oxacillin (70 mg/kg body weight) from the 12th to 16th day of pregnancy resulted in an enhancement of the spleen IgM antibody response in their offspring. The same treatment of nursing mothers, either on postnatal days 1-4 or 13-16, depressed the humoral response of the offspring. When the litters of control mothers and mothers treated with oxacillin from the 11th to 15th day of pregnancy were cross-fostered at birth, the offspring born of saline-treated mothers and nursed by oxacillin-treated mothers as well as the offspring born to oxacillin-treated mothers and nursed by control mothers produced significantly higher amounts of spleen anti-SRBC IgM than the control offspring. The results suggest that the alteration of the immune response in offspring of mice treated by oxacillin during pregnancy was induced not only in the prenatal period, but also postnatally by factors originating from effects of oxacillin on the maternal organism.

Three and four-day-old chick embryos were exposed to thalidomide as well as to its hydrolysis products before and after in vitro biotrasformation of these compounds with rat liver homogenate. Significant embryotoxic effects of 30 and 100 micrograms doses per embryo encountered only in the case when the products of alkaline hydrolysis of thalidomide were pretreated with rat liver homogenate.