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Notes: Following a study of fibre population fibre size was determined in three muscles of different functional purpose in four breeds of dog with different locomotory capacities. Samples were taken from specific sites in the tibialis cranialis (extensor), flexor digitalis medialis (flexor) and pectineus (adductor) muscles of 27 dogs of four different breeds—German shepherd, Spanish greyhound, Spanish mastiff and Iberian hound—. Samples were subjected to histochemical analysis using ATPase (pH 9.4) and fibre size was assessed using an IBAS-2 Kontron image analyser.

Notes: The results from a recent study by Bruce and Schurg (1990) indicate that the gluteus medius (Gm) of the horse is a complex muscle subdivided by an internal tendinous sheet into two regions (dorsal and ventral) which may subserve different functions. In the present study, both regions were found to contain a similar proportion of histochemically-determined muscle fibre types. Fibre type composition did not generally vary over the length of the muscle at the same relative depth. In contrast, there was a significant tendency for the percentage of type I fibres to increase gradually in accordance with depth. These histochemical results do not suggest that the two regions of the Gm assume distinct functional roles; they do, however, indicate that at a given relative depth the muscle fibre type distribution is relatively uniform over the length of the muscle. Nevertheless, care should be exercised in sampling and interpreting data obtained from limited biopsy of equine Gm, due to the substantial histochemical variation of fibre type compositon as a function of sampling depth.

Notes: A histochemical and morphometric study of the cranial tibial muscle of the greyhound, the German shephard and the fox terrier was carried out using hematoxyline-eosin, PAS, Gomori trichrome, SDH, LDH, NADH-tr and ATPase staining (with pH adjustments to both acidic and basic levels), with the goal of comparing the proportion and distribution of type I and type II fibers within the muscle. Significant differences were found between the three breeds of dogs. It is suggested that these differences are related to the locomotor activities of the three breeds.

Notes: Mediante inyección por Arteria renalis de solución acetonada de resina vinilica y corrosión clorhídrica se obtienen los llenados arteriales de riñones de 52 perros, 40 de los cuales fueron nefrectomizados (20–22 días antes de la inyección) unilateralmente. En todos estos órganos, que hubieron de suplir la función renal por ausencia del homólogo opuesto (órganos controles) se estudiaron de modo systemático las modificaciones morfológicas y de calibre que se operan en los trayectos arteriales más directamente vinculados con la aferencia de sangre a los glomérulos, así como la respuesta vicariante de determinados eslabones del circuito complementario de riego colateral. Las estimaciones se fundamentan en un análisis estadístico y, sobre determinadas estructuras vasculares, se discuten e interpretan aspectos de interés morfofuncional.Las anastomosis que contræen las ramas de las arterias interlobulares y, sobre todo las arterias perforantes, representan un dispositivo potencial en el trofismo compensatorio del riñón canino. Ante exigencias funcionales las sucesivas ramas arteriales consideradas a partir de las arterias arqueadas responden uniformemente al riego vicariante con incrementos proporcionales de sus calibres. En el caso de las arterias perforantes aglomerulares dicho incremento fué del doble, e incluso más, respecto al diámetro medio de dichas arterias en órganos normales.〈section xml:id="abs1-2"〉〈title type="main"〉ZusammenfassungVeränderungen in den Nierenarterien nach einseitiger Nephrektomie beim HundMittels Injektion der Nierenarterie mit einer Löusung von Vinyl in Azeton und anschlieβSzender Korrosion in Salzsäuure wurden die Nieren von 52 Hunden untersudit, von denen 40 einseitig nephrektomiert wurden (20 bis 22 Tage vor der Injektion). An alien Nieren, die die Funktion des entfernten Organs übernehmen mußten, wurden systematisch die morphologischen Veränderungen und das Kaliber der afferenten Arterien und des Kollateralkreislaufes untersudit. Auf Grund statistischer Analysen der einzelnen Gefäß-abschnitte werden verschiedene Probleme der funktionellen Morphologie diskutiert und erklärt.Die Anastomosen zwischen den Ästen der Aa. interlobulares und besonders die Aa. perforantes stellen den Gefäßteil der Hundeniere dar, der imstande ist, die trophische Kompensation durchzuführen. Je nach funktionellem Bedarf passen diese Äste ihr Kaliber dem vikariierenden Blutstrom an. Im Falle der Aa. perforantes ohne Glomerulus stieg die Kaliberzunahme bis auf mehr als das Doppelte im Vergleich zum Durchmesser dieser Arterien im Mittelwert normaler Nieren.〈section xml:id="abs1-3"〉〈title type="main"〉SummaryChanges in the intrarenal arteries after unilateral nephrectomy in the dogThe intrarenal arteries of 52 dogs were studied after injection with vinyl in acetone and corrosion with hydrochloric acid. Forty of these dogs had been unilaterally nephrectomized 20–22 days prior to being sacrificed. The morphological changes and the caliber of the afferent arteries and of the collateral circulation, were systematically examined in all kidneys that had to assume the function of the sister organ. Utilising statistical analysis of the several arterial segments, various problems of their functional morphology could be explained and were discussed.The anastomoses between the branches of the interlobar arteries and, especially, the perforating arteries were the segments of the intrarenal arterial system which appeared to be able to compensate. Depending on functional requirements, these segments seemed to adjust their caliber to the change in blood flow. In the case of the perforating arteries (without glomeruli), the increase in caliber more than doubled as compared to that in normal kidneys.〈section xml:id="abs1-4"〉〈title type="main"〉RésuméModifications artèrielles au niveau des reins, après néphrectomie unilatéral, chez le chienAprès injéction ďune solution acéonique de Vinyl dans les artéres rénals, suivie de corrosion chlorhydrique, on a étudié les reins des 52 chiens dont 40 furent néphrectomisés unilateralement (20–22 jours avant ľinjection). Sur tous les reins qui durent assurer la vicariance de ľorgane enlevé, on a fait ľétude systematique des modifications morphologiques aussi que des calibres des artères afferentes et des trajets circulatories collateraire. Sur la base ďanalyses statistiques portant sur les différents segments vasculaires, on discute et éclaire plusieurs problémes de morphologie fonctionnelle.Les portions vasculaires capables ďassurer la compensation trophique sont représentéds, dans le rein du chien, par les anastomoses entre les rameaux des artères interlobulaires (Aa. interlobulares) et, ďune façon particulière, par les artères perforantes (Aa. perforantes). Selon les besoins fonctionnels, ces vaisseaux adaptent leur calibre au feux sanguin de vicariance. Pour les artères perforantes nonglomerulaires, leur calibre et plus que doublé, compareéà celui qu'elles préentent, en moyenne, dans un rein normal.

Notes: The effect of exercise training on the longissimus muscle types was investigated in rats. There were four groups of rats, each exposed to exercise of equal intensity, but of varying duration. A segment of the longissimus muscle between the 2nd and 4th lumbar vertebrae was used for muscle fiber classification with histochemical ATPase classification.With exercise there were no significant changes in the percentage of the muscle comprised of type I muscle fibers. There was, however, significant increase in the percentage of type II A fibers. This paralleled a decrease in type II B fibers. The percentage of FG fiber types decreased significantly in all groups studied. There was a correlation between intensity and duration of exercise and the degree of decrease seen in the latter fiber types. An increase in oxidative muscle capabilities was evidenced by the changes observed in the subtypes of class II fibers.

Notes: Abstract Nitrogen-starved sunflower plants (Helianthus annuus L. cv. Peredovic) cannot absorb NO 3 − or NO 2 − upon initial exposure to these anions. Ability of the plants to take up NO 3 − and NO 2 − at high rates from the beginning was induced by a pretreatment with NO 3 − . Nitrite also acted as inducer of the NO 2 − -uptake system. The presence of cycloheximide during NO 3 − -pretreatment prevented the subsequent uptake of NO 3 − and NO 2 − , indicating that both uptake systems are synthesized de novo when plants are exposed to NO 3 − . Cycloheximide also suppressed nitrate-reductase (EC 1.6.6.1) and nitrite-reductase (EC 1.7.7.1) activities in the roots. The sulfhydryl-group reagent N-ethylmaleimide greatly inhibited the uptake of NO 3 − and NO 2 − . Likewise, N-ethylmaleimide promoted in vivo the inactivation of nitrate reductase without affecting nitrite-reductase activity. Rates of NO 3 − and NO 2 − uptake as a function of external anion concentration exhibited saturation kinetics. The calculated Km values for NO 3 − and NO 2 − uptake were 45 and 23 μM, respectively. Rates of NO 3 − uptake were four to six times higher than NO 3 − -reduction rates in roots. In contrast, NO 2 − -uptake rates, found to be very similar to NO 3 − -uptake rates, were much lower (about 30 times) than NO 2 − -reduction rates. Removal of oxygen from the external solution drastically suppressed NO 3 − and NO 2 − uptake without affecting their reduction. Uptake and reduction were also differentially affected by pH. The results demonstrate that uptake of NO 3 − and NO 2 − into sunflower plants is mediated by energy-dependent inducible-transport systems distinguishable from the respective enzymatic reducing systems.

Notes: Abstract Activities of nitrate reductase (NR; EC 1.6.6.1), nitrite reductase (NiR; EC 1.7.7.1), glutamine synthetase (GS; EC 6.3.1.2) and glutamate dehydrogenase (GDH; EC 1.4.1.3) were measured in cotyledons of sunflower (Helianthus annuus L. cv Peredovic) seedlings during germination and early growth under various external nitrogen sources. The presence of NO 3 - in the medium promoted a gradual increase in the levels of NR and NiR activities during the first 7 d of germination. Neither NR nor NiR activities were increased in a nitrogen-free medium or in media with either NH 4 + or urea as nitrogen sources. Moreover, the presence of NH 4 + did not abolish the NO 3 - -dependent appearance of NR and NiR activities. The increase of NR activity was impaired both by cycloheximide and chloramphenicol, which indicates that both cytoplasmic 80S and plastidic 70S ribosomes are involved in the synthesis of the NR molecule. By contrast, the appearance of NiR activity was only inhibited by cycloheximide, indicating that NiR seems to be exclusively synthesized on the cytoplasmic 80S ribosomes. Glutamine-synthetase activity was also strongly increased by external NO 3 - but not by NH 4 + or urea. The appearance of GS activity was more efficiently suppressed by cycloheximide than chloramphenicol. This indicates that GS is mostly synthesized in the cytoplasm. The cotyledons of the dry seed contain high levels of GDH activity which decline during germination independently of the presence or absence of a nitrogen source. Cycloheximide, but not chloramphenicol, greatly prevented the decrease of GDH activity.

Notes: Abstract The aim of this study was to determine the influence of a 10-month training programme on the linear, temporal and angular characteristics of the fore and hind limbs at the trot in the Andalusian horse, using standard computer-aided videography. Sixteen male Andalusian horses were observed before and after training. Six strides were randomly selected for analysis in each horse and linear, temporal and angular parameters were calculated for fore and hind limbs. The training programme used here produced significant changes in kinematic parameters, such as shortening of stride length, and increase in swing duration and a decrease in hind limb stance percentage. No significant differences were recorded in the angular values for the forelimb joints. In trained horses, the more proximal joints of the hind limb, especially the hip and stifle, had a greater flexion while the fetlock showed a smaller extension angle. At the beginning of the swing phase, hip and stifle joints presented angles that were significantly more flexed. When the hind limbs came into contact with the ground, all the joints presented greater flexion after training.