[MRI of experimental focal cerebral ischemia in sheep]. / MR-Bildgebung eines experimentellen Schlaganfallmodells beim Schaf.

PURPOSE: With respect to the specific characteristic of rete mirabile epidurale rostrale in sheep, the aim of this study was to investigate the use of time of flight (TOF) magnetic resonance angiography (MRA) to observe vascular anatomy and to validate MCA occlusion in a new model of experimental focal cerebral ischemia by permanent middle cerebral artery (MCA) occlusion in sheep (designed to study stroke therapy using autologous stem cells from umbilical cord blood). Furthermore, we wanted to assess the extent and natural time course of ischemic focal brain injury in sheep using functional and morphological magnetic resonance imaging (MRI). MATERIALS AND METHOD: 13 Merino sheep were examined. In 4 of the animals all, in 5 sheep 1 or 2 MCA branches were occluded and in 1 one case touched (sham operation). 4 controls did not undergo a surgical procedure. 23 MRI sessions were performed in 10 sheep. These sessions included T1, T2, T2* sequences, diffusion-weighted imaging (DWI) and TOF MRA before and 2-46 days after the onset of stroke using a 1.5 T clinical MR scanner. Corrosion casts of the cerebral arteries of 3 sheep were prepared and compared to MRA. RESULTS: The MRA visualized the vessel anatomy or occlusion distal to the rete mirabile. Anatomical variants concerning the variant origin of the MCA and inconstant arteria choroidea rostralis and communicans rostralis were revealed. Sheep with occluded left MCA showed space occupying lesions with a drop in ADC values. Depending on the number of preserved MCA branches (0; 1; 2), highly significant (p < 0.001) differences in lesion size (21 +/- 5.7; 13; 1.7 +/- 1.3 ml) could be found. No indication of ischemia but minimal contusion damage was observed in the sham operated animal. CONCLUSIONS: In our study focal cerebral ischemia was generated in sheep and examined using MRI for the first time. Depending on the occlusion type, the model produced a reproducible lesion size. TOF-MRA proved to be able to clearly depict the anatomy, variants and occlusion type of cerebral arteries in sheep in a manner comparable to that of corrosion casts despite the upstream rete mirabile. MRI with MRA is a useful tool for assessing the extent of brain injury and the type of MCA occlusion and is therefore suitable for non-invasive monitoring of lesion development upon stroke.

Ataxia and disequilibrium in domestic ducks (Anas platyrhynchos f. dom.) with intracranial lipomas.

Four birds in a flock of 125 purebred Crested ducks (Anas platyrhynchos f. dom.) had cerebellar signs of unknown etiology. They had radiographically evident perforations of various sizes in the parieto-occipital calvaria. Gross necropsy of euthanatized ducks revealed yellow intracranial masses in the brain of each. Histologically, these masses were intracranial lipomas consisting of univacuolated fatty tissue separated into lobules by strands of connective tissue. The masses had caused serious deformation of the rostral part of the cerebellum, leading to a nearly complete flattening of cerebellar folia, and were interpreted as the cause for the central nervous clinical signs observed. These intracranial lipomas were similar to those previously reported in other animals and humans.

[Ultrasonographic examinations of fetal growth of sheep between day 20 and day 50 of gestation]. / Ultrasonographische Messungen zum fetalen Wachstum des Schafes zwischen dem 20. und 50. Trächtigkeitstag.

Previous studies on embryonic and fetal growth in sheep were mostly transversal using animals killed at various stages of gestation. Until now it was difficult to monitor the development of individual embryos/foetuses during pregnancy, especially during the first and second pregnancy month. Real-time ultrasound as a non invasive method could be an appropriate method for examination of embryonic and early foetal development in sheep. The aim of this study was to determine the embryonic and foetal development of the crown-rump-length (CRL) in pregnant ewes in relation to the number of fetuses and/or the breed. Between the 20th and 50th day of pregnancy the embryos/foetuses showed an exponential growth which can be best described by the equation of the form CRL (mm) = W * exp (k * day of pregnancy). The individual variability in embryofetal growth is in part due to the number of embryos per sheep and the sheep breed.

[Postnatal skeletal and body weight in beagles]. / Das postnatale Wachstum des Skeletts und der Körpermasse beim Beagle.

Growth of beagles is described on the basis of body weight and 14 bone measures. Eighteen male and 19 female dogs were investigated at 14 different ages from birth to the 13th month of life. Characteristics of the growth curves were evaluated using the modified Janoschek growth curve. For the classification into dwarfish, low, normal, big and gigantic growth, the growth curves are presented with percentiles. The arithmetic means and standard deviations for both sexes are presented in tables. Additionally, the degrees of maturity at birth (relative proportion of final weight or bone measure), the point of inflection for the growth curve, the times to grow to 50 and 95% of the final measures, and the asymptotic measures are also presented in tables. Sex differences in growth for the body weight and bone measures are discussed. Growth differences between large and small dog breeds are considered. The conclusion is drawn that the feeding of dogs has to be adapted to the growth course.

[Growth of the cloacal bursa (bursa of Fabricius) and spleen in ducks]. / Wachstum von Bursa Cloacalis (Fabricii) und Milz bei Enten.

The growth in weight of both the bursa of Fabricius and the spleen was investigated in different stocks of ducks between hatching and 154 days of age. The data were analysed by fitting the Janoschek growth curve and the allometric formula. Both organs showed rapid growth to their maximum dimensions and early points of inflection. The regression of the cloacal bursa started at about 12 weeks of age in Pekins and Mallards. In the Muscovy, the involution begins beyond the period of investigation. Allometrically, a biphasic relationship was found. Starting with positive allometry, the allometric exponent decreased to negative or isometric (Muscovies) values within the second week of age. If the organ weights are compared on the basis of these allometric relationships, Pekins had bursa weights that were about 30% higher than those in Mallards. For the spleen, there was no difference between wild and domesticated ducks.

Growth of the digestive organs in ducks with considerations on their growth in birds in general.

1. Growth of the oesophagus, proventriculus, gizzard, intestine, liver and pancreas weight was investigated in Mallards, White Pekins, Muscovies and a Muscovy x White Pekin cross. The birds varied in age between hatching and 154 d. The data were analysed by fitting both the Janoschek growth curve and the allometric formula. 2. The growth rate of all organs, except the oesophagus, peaked earlier (30 d for Muscovies and 14 d for the other breeds) than body weight and they grew faster to any given percentage of their final weight. In contrast, oesophagus weight showed growth curve characteristics similar to body weight. 3. Oesophagus weight showed simple, slightly negative allometry. The remaining organs followed complex allometry that can approximately be described by 2 allometric stages. The 1st phase was isometric to positive allometric. The 2nd showed marked negative allometry. 4. These growth patterns are assumed to be generally present in birds.

Muscle growth in wild and domestic ducks.

1. Increases in weight of the M. pectoralis, M. iliotibialis lateralis and M. flexor cruris lateralis were measured in mallards, White Pekins, Muscovies and a Muscovy x White Pekin cross from hatching to 154 days of age. Growth with respect to age was analysed using the Janoschek growth curve. 2. The M. pectoralis was less developed at hatching than both leg muscles. Furthermore, it showed a slower growth to its final weight and a later age at maximum growth than both leg muscles. 3. Pekins exhibited a faster Pectoralis and Iliotibialis lateralis muscle growth than mallards and Muscovies. The latter attained greater weights than Pekins at later ages owing to a higher asymptote. The cross showed the fastest muscle growth. 4. With respect to body weight, the Pectoralis is characterised by isometry followed by strongly positive allometry. This multiphasic allometry implies that relative muscle weights should not be used and the value of the allometric exponent strongly depends on both the beginning and duration of the period of investigation. Leg muscles showed isometric to slightly negative, simple allometry.

[Ultrasonographic examination of the placentoma development in pregnant sheep]. / Ultrasonographische Untersuchungen zum Plazentomwachstum beim trächtigen Schaf.

The aim of this study was to determine the in vivo development of the placentome diameter during the pregnancy in sheep. 32 ewes of four different breeds were involved. After the first detection of the placentomes (28 day p. c.) the ewes were scanned by transrectal ultrasound (Aloka SSD 500, 5 MHz linear probe) in a standing position every second or third day until day 50 p. c. and after the every week until parturition. The maximum diameters of 10 placentomes were measured. The placentome diameter increased rapidly until the middle of the third pregnancy month followed by a slight decrease. Between the 110th day p. c. and the parturition the diameter was nearly constant, but 40% of the animals showed a second increase at this time. The placentome diameter could be a good mark to describe the function of the placenta in sheep but it is only stipulated fit for the diagnosis of the state of the pregnancy.

Posthatching myofiber development in the M. pectoralis of White Pekin Ducks.

BACKGROUND: A posthatching transformation of fast-twitch oxidative-glycolytic (FTO) to fast-twitch glycolytic (FTG) fibers in the breast muscle in domestic chickens and turkeys is well documented. There is, however, no information on the situation in Anseriformes having a M. pectoralis with a mixed fiber composition in adults. Differences in the growth of the different fiber types were reported for some muscles in ducks as well as in other birds. They are examined in the main flight muscle using growth curve analysis, until now mostly applied to the analysis of overall growth. METHODS: Biopsies were taken longitudinally from the M. pectoralis, Pars thoracica, of 40 White Pekin Ducks at 11 different ages from hatching through day 146. The samples were processed for a combination of nicotinamide adenine dinucleotide tetrazolium reductase and myosin adenosine triphosphatase after acid preincubation at pH 4.1. Mean fiber diameter was determined for the different fiber types in relation to age. The Janoschek growth curve was fitted to these values. RESULTS: FTG fibers were first detected at 20 days of age. Thereafter, the fiber composition hardly changed. When distinguishable by enzyme histochemistry, FTG fibers were already larger in diameter than FTO. There were only gradual differences in the growth pattern. FTG fibers, however, showed much higher absolute, percentage, and relative growth rates. The radial growth of myofibers is slow when compared to other one-dimensional measurements. CONCLUSIONS: Fiber transformation seems to take place within a short age period. However, further studies are necessary to discriminate effects resulting from sample depth. FTG fibers are presumably recruited from those FTO fibers that show higher growth rates. Growth curve analysis, more frequently used in gross morphological studies, provides an analytical tool for evaluating growth processes of cells and tissues as well. Fiber size differences are mainly due to a higher growth rate in FTG fibers, whereas the growth patterns show only minor differences.

Scanning electron microscopy of the canine placenta.

The zonary placenta of the dog is peculiar in providing three morphologically and functionally distinct areas for transplacental exchange: the endotheliochorial labyrinth of the girdle zone, the hemochorial hemophagous zone of the marginal hematoma and the epitheliochorial free polar zone. Besides, the yolk sac persists throughout pregnancy. Scanning electron microscopy (SEM) was used to study these structures comprehensively with special emphasis on natural surfaces because of their relevance for exchange processes. Unequal cell diameter was typical for trophoblast cells. Surface specializations were observed on trophoblast cells lining the marginal hematoma, the free polar zone and the glandular chambers as well as on uterine epithelial cells of the glandular chambers and of the deep glands. In addition, maternal and fetal endothelial cells in the labyrinth showed major differences. Whereas fetal endothelial cells were extremely thin and polygonal in shape, maternal vessels were lined by thick endothelial cells exhibiting a complex interdigitation pattern of cytoplasmic processes. Thus, most of the natural surfaces could readily be distinguished by SEM due to their typical appearance.

[Changes in the shape and growth of motor endplates of mm. fibularis longus, semitendinosus and longissimus in pigs]. / Zu den Formveränderungen und zum Wachstum der motorischen Endplatten der Mm. fibularis longus, semitendinosus et longissimus bei Schweinen.

Age-related changes in motor endplates were studied in the fibularis longus, semitendinosus and longissimus muscles in pigs. They develop from small, compact AChE-active figures in fetuses to typical myoneuronal synapses with a branched subsynaptical structure of AChE-active units. High correlations were found between size of endplates and both myofibre diameter and body mass. Growth analyses with respect to age, as well as allometrical approaches, showed that endplate growth slightly precedes that of myofibres, with both having similar growth patterns. The morphological changes, however, imply that the increment of synaptical area could lag behind that of myofibres.

Bone growth in ducks through mathematical models with special reference to the Janoschek growth curve.

The Janoschek growth curve was reviewed and a reparameterized form was presented which includes 4 biologically interpretable parameters: the weight at hatching/birth (W0), asymptotic (adult) weight (A), the time to grow to half of the final weight (t50) and a shape parameter (p) adjusting the degree of maturity when growth rate peaks. The model obtained was compared to the Richards, Bertalanffy, Gompertz and Logistic growth curve using bone weight data in White Pekin ducks. The Janoschek yielded least residual sums of squares for humerus mass and the Richards model for femur mass with only minor differences between both equations. All 3-parameter models failed to give reasonable estimations of the weight at hatching; in some cases further growth curve characteristics were unrealistic. The femur showed a higher degree of maturity at hatching, an earlier growth rate peak and its development preceded that of the humerus. This differential growth is an evolutionary feature first seen in birds.

[Quantitative changes in the capillary supply of selected muscles of turkeys, ducks, rats and swine during postnatal development]. / Quantitative Veränderungen in der Kapillarisierung ausgewählter Muskeln von Pute, Ente, Ratte und Schwein während der postnatalen Entwicklung.

The capillary and muscle fibre density, the ratio of capillaries to fibres and the mean diffusion distance were determined in histological cross sections of the M. pectoralis of turkeys and ducks, the M. semitendinosus of rats and the M. longissimus of pigs between hatching or birth and maturity. The data were analyzed by fitting the Janoschek growth curve. The capillary and fibre density decrease asymptomatically, the diffusion distance increases. The M. longissimus of the adult pig is provided with the lowest capillary density resulting in the greatest diffusion distance. The highest capillarity was found in the M. pectoralis of ducks.

Heart and body growth in ducks.

Growth of body and heart weight in drakes was measured to 154 days of age in Mallards, 2 lines of White Pekins (Anas platyrhynchos), Muscovys (Cairina moschata), and a Muscovy x White Pekin cross. Allometric heart growth was slightly negative in the Mallard and its domestic forms (allometric exponent 0.895 < b < 0.943) whereas no significant difference from isometry was detected in Muscovy ducks and its cross. The relation between heart and body weight, using all stocks combined, yielded an exponent b = 0.937, being significantly smaller than 1. Coefficients of determination were high varying between 0.981 and 0.992. Breaks, i.e. changes of the slope during the postnatal development, could not be detected in any of the stocks. Using the modified Janoschek growth curve, both heart and body weight showed a similar growth pattern with respect to time. The degree of maturity at hatching and at the point of inflection (ui) was similar within stocks for both weights. This was also true for the age at maximum growth. The similarity between heart and whole body growth patterns, which is not found in most of the other internal organs, implies strong functional constraints. The ui values varied between 32 and 50% which should be taken into account when choosing an appropriate model. Differences among the various types of ducks resulting from their origin or domestication are discussed.

[The growth of the skeleton, body mass and muscle fiber diameter of the turkey (Meleagris gallopavo) from hatching to the 224th day]. / Zum Wachstum von Skelett, Körpermasse und Muskelfaserdurchmesser der Pute (Meleagris gallopavo) vom Schlupf bis zum 224. Lebenstag.

Growth of body mass, femur, tibiotarsus, and tarsometatarsus length as well as the diameter of muscle fibers in the M. pectoralis were measured in (Large White) female turkeys between birth and day 224. Growth-specific approximations were established with the Janoschek function as modified by Sager (1978) and with the Logistic function. While the Janoschek function fairly described the growth of the turkey, the Logistic function throughout gave beginning values that were too high and theoretical end values that were too low. Of the five growth parameters that were measured, the diameter of the muscle fibers showed its maximal rate of growth first on day 21. The following decrease in growth rate took the following sequence: length of tarsometatarsus, femur, and tibiotarsus, diameter of muscle fibers, body mass. 99% of growth had occurred in the tarsometatarsus length on day 109, femur length on day 117, tibiotarsus length on day 138, diameter of muscle fibers on day 166, and the body mass on day 231. A comparison of this growth with that of other domestic fowl showed close relationships between the way turkeys and chickens grow.

[The capillarization of the M. pectoralis of the turkey (Meleagris gallopavo) from hatching to the 280th day of life]. / Die Kapillarisierung des M. pectoralis der Pute (Meleagris gallopavo) vom Schlupf bis zum 280. Lebenstag.

The capillarization of the M. pectoralis was examined in the turkey as it changed with age. Examined was the density of the muscles fibers (per mm2), the density of the capillaries (per mm2) and the quotient muscle fibers/capillaries. In accordance with the sequence of the original data four functions of organismic growth (slightly altered) were utilized for the approximation of the data for descending amounts: Pütter/Bertalanffy (1920, 1934); Richards (1959); Janoschek enlarged after Sager (1980) and Richards enlarged after Sager (1980). The approximations were made via nonlinear regressions, whereby the sum of the error amounts and the sums of the error squares served as criteria of quality. The results including the deduced initial and end amounts are combined in tables which also contain the parameter of the way the computations were conducted.

[Relationship between body mass, brain mass and craniometric parameters in the miniature pig Mini-Lewe]. / Beziehungen zwischen Körpermasse, Gehirnmasse und kraniometrischen Parametern beim Miniaturschwein Mini-Lewe.

The relations between skull measurements, brain mass, and body mass were investigated in 30 female miniature pigs, being 6 month old. The relatively low correlation coefficients between the variables indicate a high variability in skull shape. We found an allometric exponent of 0.236 for the relation between brain and body mass with a coefficient of determination of 0.29. Both measurements show a highest correlation with the arcus zygomaticus width, which shows close relations with the occipital height and condylobasal length.