Anuria, omphalocele, and perinatal lethality in mice lacking the CD34-related protein podocalyxin.

Podocalyxin is a CD34-related sialomucin that is expressed at high levels by podocytes, and also by mesothelial cells, vascular endothelia, platelets, and hematopoietic stem cells. To elucidate the function of podocalyxin, we generated podocalyxin-deficient (podxl(-/)-) mice by homologous recombination. Null mice exhibit profound defects in kidney development and die within 24 hours of birth with anuric renal failure. Although podocytes are present in the glomeruli of the podxl(-/)- mice, they fail to form foot processes and slit diaphragms and instead exhibit cell--cell junctional complexes (tight and adherens junctions). The corresponding reduction in permeable, glomerular filtration surface area presumably leads to the observed block in urine production. In addition, podxl(-/)- mice frequently display herniation of the gut (omphalocele), suggesting that podocalyxin may be required for retraction of the gut from the umbilical cord during development. Hematopoietic and vascular endothelial cells develop normally in the podocalyxin-deficient mice, possibly through functional compensation by other sialomucins (such as CD34). Our results provide the first example of an essential role for a sialomucin in development and suggest that defects in podocalyxin could play a role in podocyte dysfunction in renal failure and omphalocele in humans.

Quantification of equine ground reaction force patterns.

A method was developed to quantify the ground reaction force pattern of the horse. A number of selected force amplitudes and peak-time positions in the normalized stance phase of left and right contralateral limbs were used to calculate symmetry indices. Data from each limb were compared with those of a 'standard horse' resulting in limb indices. The combination of amplitude and peak-time symmetry and limb indices yielded one H(orse)INDEX. These indices were useful for comparison of different horses and for the evaluation of lameness and treatment.

Unilateral distension of the tarsal sheath in the horse: a report of 11 cases.

Eleven horses with unilateral distension of the sheath are reported with emphasis on the use of plain and contrast radiography in diagnosis. Six had associated bony abnormalities of the sustentaculum tali, and two of these showed destructive or mixed destructive and proliferative lesions resulting from osteomyelitis. One horse had a fracture of the sustentaculum. In three horses proliferative changes were found. Bony changes were best demonstrated on a dorsomedial-plantarolateral oblique view. Contrast radiography of the tarsal sheath was performed in five cases without, and two horses with, associated bony lesions. In five cases ballooning with or without folding of the proximal aspect of the sheath was demonstrated. Additional band-like filling defects (two cases), triangular filling defect (one case), nodular intra-tendovaginal masses (two cases), or an extra-tendovaginal mass (one case) were noticed. The remaining two horses showed a semicircular collar shape dilation of the proximal aspect of the sheath. Contrast radiography appeared to be a helpful tool for the examination of tarsal sheath lesions. Two horses with associated bony changes were destroyed immediately after diagnosis, one failed to recover following surgical intervention and in three horses the outcome was unsatisfactory after conservative treatment. Three horses without associated bony lesions recovered completely after conservative treatment. One was operated on subsequently; the results are promising but the outcome of this case is not yet known. One was sold shortly after diagnosis and lost to follow up.

Distribution of ground reaction forces of the concurrently loaded limbs of the Dutch Warmblood horse at the normal walk.

The distribution of the ground reaction forces (GRF) over the concurrently loaded limbs of the normally walking horse was determined from 'representative' GRF patterns of all limbs, which were plotted in correct time order after analysis of simultaneously taken high-speed film. This procedure visualises the GRF patterns of each of the four limbs in relation to the GRF pattern(s) of the one or two concurrently loaded limb(s) during a complete stride. In 15 clinically sound horses the mean averaged GRF data and temporal stride parameters showed an almost complete symmetry between both the forelimbs and both the hindlimbs and resulted in a load distribution during the first half of the stride being almost identical to those in the second half of the stride. The transverse horizontal force (Fx) was maximum during the unilateral support phase. No more than one limb at a time contributed to either the deceleration or acceleration longitudinal horizontal (Fy) force. The total vertical (Fz) force of the concurrently loaded limbs during a complete stride fluctuated between 7 to 12 N/kg body weight. In a left forelimb lame horse, the decreased GRF amplitudes were compensated by increased GRF amplitudes in the three other limbs during both the swing phase and stance phase of the lame limb. Due to alterations of both GRF data and temporal stride parameters of the lame limb, as well as the three other limbs, the distribution of the GRF during the complete stride was changed dramatically.

Ground reaction force patterns of Dutch Warmblood horses at normal walk.

The ground reaction force patterns from 20 clinically sound Dutch Warmblood horses (Group A) were recorded at the normal walk. The data from four to 10 stance phases of each limb were computer averaged after normalisation to the animal's body mass and to the stance time. This analysis method allowed comparison of data from left and right fore- and hindlimbs within and between horses. The left-to-right symmetry in the reaction force peaks of contralateral limbs of one horse exceeded 90 per cent. The time in the stance phase at which the peaks occur were even more symmetrically distributed. A characteristic force-force diagram was constructed by plotting the longitudinal horizontal and the vertical ground reaction forces against each other; in this way the symmetry of loading of contralateral fore- and hindlimbs could be interpreted easily. Force plate tracings were obtained from eight horses (Group B) in three successive years. The similarity of the tracings from a sound, well-trained horse over that period was better than the differences between horses of the same breed.

The use of H(orse) INDEX: a method of analysing the ground reaction force patterns of lame and normal gaited horses at the walk.

The amplitudes, impulses and times of occurrence of a number of selected peaks in the ground reaction force tracings of 17 horses with various clinical histories were compared with those of 20 horses used to establish values for the 'standard' Dutch Warmblood horse. The resulting factors were combined, using different weighting factors, into indices characterising each limb. The symmetry between the loading of the forelimbs and the hindlimbs was used to calculate amplitude and peak-time symmetry indices. Limb and symmetry indices were combined in one H(orse) INDEX. This method of quantifying the ground reaction force pattern, together with appropriate graphic display of the tracings, was useful in clinical evaluation of force plate measurements.

Ground reaction force patterns of Dutch warmblood horses at normal trot.

This study was undertaken to establish limb loading patterns of sound horses at the trot, to provide a data base against which results for lame horses could be compared. Ground reaction force (GRF) data were collected from 20 clinically sound Dutch Warmblood horses. The data from at least 5 stance phases of each limb were averaged after standardisation to the animal's body mass and to the stance phase duration and resulted in 'representative' GRF data. The symmetry in the vertical GRF peak amplitudes, impulses and the stance phase duration comparing left and right limbs exceeded 97%. By averaging the 'representative' GRF of the 20 horses a 'standard' GRF pattern of the Dutch Warmblood horse at the trot was constructed. The GRF patterns at the trot, compared with those at the walk, showed only one vertical force peak in forelimbs and hindlimbs (11.59 N/kg and 10.21 N/kg, respectively). The retardatory and propulsory forces were distributed over the forelimbs and hindlimbs in such a way that the forelimbs contributed more to retardation (peak forces 1.13 and 0.79 N/kg), and the hindlimbs more to propulsion (-0.84 and -1.17 N/kg, respectively).

External loads on the limbs of jumping horses at take-off and landing.

Using a force plate, ground reaction force (GRF) patterns at take-off and landing between the hooves and the ground were recorded for all limbs of 5 Dutch Warmbloods jumping a 0.8-m vertical fence from the right-leading canter. Distribution of the GRF and force impulses over the 4 limbs at take-off and landing were considerably different from those recorded at the normal canter. At take-off, the propulsory GRF of the hind limbs were 3 to 5 times higher than at the normal canter, depending on the jumping technique of the horse. At landing, the propulsory GRF were mainly increased in the trailing forelimb and in both hind limbs. The vertical GRF amplitudes and force impulses were of similar magnitude to those at the canter, although increases up to 160% were found in the hind limbs of the horse with the worst jumping technique. The trailing forelimb carried the highest loads, up to twice the animal's body weight; GRF amplitudes tended to increase when higher fences were used. However, the jumping technique of the horse may have more influence, because an easily jumping horse could clear a 1.3-m-high fence with similar loads on the limbs.

Ground reaction force patterns of Dutch Warmbloods at the canter.

Ground reaction force (GRF) patterns from 20 clinically sound Dutch Warmbloods were recorded at the right fore-leading canter, and a standard horse was composed. These GRF data for the standard can be used for evaluation of jumping horses. The GRF patterns were asymmetric for all 4 limbs. The leading right forelimb decelerated the body. The trailing left forelimb propelled the body and decelerated it slightly. The trailing left hind limb propelled, and the leading right hind limb contributed to deceleration and propulsion. Referred to the maximal vertical load of the leading right forelimb, the load of the trailing left forelimb was 25% more; the load of the right hind limb was slightly less, whereas the load of the left hind limb was about 80% of that value.

Software for analysis of equine ground reaction force data.

Software for analysis of force plate recordings of the horse at normal walk is described. The data of a number of stance phases are averaged to obtain a representative tracing of that horse. The amplitudes of a number of characteristic peaks in the force-time curves are used to compare left and right front limbs and left and right hind limbs. The averaged tracings are plotted, default on the line printer or, via separate program, on a high quality pen plotter. A version of the program applicable for analysis of human force plate recordings, is available.

Kinematics of treadmill versus overground locomotion in horses.

A kinematic analysis was carried out to compare treadmill and overground locomotion in horses at the trot. Stride variables and limb and trunk movements of 10 Dutch Warmblood horses were measured using the CODA-3 gait analysis system. Overground recordings were made on a rubber ground surface and on an asphalt track. Treadmill recordings were taken after a controlled habituation programme and at the same velocities as measured overground. On asphalt, a shorthened stride duration and a decreased vertical displacement of the withers were found compared with those on rubber ground. On the treadmill, stance duration of the forelimbs was longer than for either overground condition. Correspondingly, the hind limbs were placed earlier than the forelimbs in making diagonal ground contact in overground locomotion, but this changed to preceding forelimbs on the treadmill. Both forelimbs and hind limbs were moved more caudally during the retraction phase on the treadmill, while no differences were found in the protraction angle. The vertical movement of the hooves as well as the withers was smaller on the treadmill than on rubber ground. Treadmill belt velocity decreased by 9% during the stance phase. This is supposed to be an important reason for the differences in biomechanics and kinematics between treadmill and overground locomotion, which must be kept in mind when data obtained during treadmill locomotion have to be extrapolated to overground conditions.

Infectious (septic) arthritis of the distal intertarsal and tarsometatarsal joint in cattle.

The results of treatment of infectious (septic) bone spavin in cattle admitted to the department of large animal surgery, Utrecht University, between 1961 and 1982 are reviewed. Treatment comprised either antibiotic administration, radiation or surgery, of which the latter two methods appeared to produce better results. However, radiation of the affected area was both time consuming and expensive. Therefore, surgical treatment is advocated.

[Results obtained with Dermazellon in the treatment of wounds in horses (author's transl)]. / Ervaringen met de toepassing van dermazellon bij de behandeling van wonden bij het paard.

In view of the beneficial effect of Dermazellon on the healing of wounds healing poorly, reported in human patients, a number of wounds caused by wire in horses were treated with Dermazellon. Dermazellon gel was readily applicable and produced satisfactory results.

[Radical surgery (amputation) or conservative treatment (drainage) in cases of septic pedal arthritis and navicular bursitis in cattle (author's transl)]. / Amputatie van de aangetaste klauw of drainage van het klauwgewricht bij een septische podarthritis

An observation was carried out with regard to forty-nine cows, which had been treated for a purulent necrotizing arthritis as a complication of a rear leg. In seventeen cases the pedal joint was drained by means of track made by an electric fraise. In sixteen cases the claw was amputated under the coronet and in the remaining sixteen cases the claw was sawn off above the coronet, through the second phalanx. It emerged that from the seventeen drainage-cases nine patients were retained for several laction-periods. Thirty out of the thiry-two cows where a claw-amputation had been performed, were slaughtered within one year. If a cow is not to be retained for several years after treatment, a simple amputation above the coronet is to be recommended.

[Simple amputation above the coronet as a possible method of treatment in arthritis of the pedal joint (author's transl)]. / Een eenvoudige amputatie boven de kroonrand als behandelingsmogelijkheid bij de arthritis van het klauwgewricht

One of the possible methods of treatment in arthritis of the pedal joint in cattle consists in simple amputation above the coronet. The surgical procedure in the standing animal is described and the results of this operation are reported.

[Force plate measurements for a quantitative assessment of the equine gait]. / Krachtenplatformmetingen voor een kwantitatieve beoordeling van de gangen van het paard.

Forces occurring between the hoof and the ground during the stance phase (i.e. the ground reaction forces GRF) can be analysed using a force plate. The average of a number of five to stance time and body weight normalised GRF recordings (data) will provide 'representative' GRF patterns. These can be used for objective and quantitative evaluation of various forms of therapy in equine orthopaedics as well as for locomotion research during various forms of equestrian sports.

[Experiences with half-closed castration in stallions]. / Ervaringen met de halfbedekte castratie bij de hengst.

The half-closed method of castration involves ligation of the spermatic cord enclosed in the vaginal tunic, the testicle itself lying outside the opened vaginal tunic. Of 497 horses and ponies admitted to the Department of Large Animal Surgery and castrated using this technique, 68.6 per cent recovered without complications. Although the most serious postoperative complications such as intestinal eventration and haemorrhage of the spermatic cord may be reduced to a minimum by this approach, normal healing cannot be guaranteed under the circumstances in which this method was used.

[An inventory of the castration of stallions based on a survey among Dutch veterinarians]. / Een inventarisatie van de castratie van de hengst aan de hand van een enquête gehouden onder Nederlandse dierenartsen.

To gain an insight into the procedures adopted in castrating stallions in the Netherlands, a questionnaire was sent to 670 Dutch veterinary practitioners. The 176 veterinary practitioners who replied performed 1850 castrations. Castration of the recumbent horse was preferred by 88 per cent of the veterinary surgeons. Fifty per cent preferred the open method of castration and 44 per cent the half-closed technique. A local anaesthetic was given by 65 per cent of the practitioners; 84 per cent administered antibiotics in an attempt to prevent wound infection. Postoperative complications were observed in 18 per cent of the castrations carried out.

[Primary closure of the scrotal wound in the castration of stallions]. / Primaire sluiting van de scrotaalwond bij de castratie van de hengst.

A method of castration in stallions is reported on, in which primary closure of the wound caused by castration was attempted. Primary wound-healing occurred in 90 per cent of 110 stallions showing normally descended testicles, whereas this proportion was 97.4 per cent in thirty-eight unilaterally cryptorchid stallions in which the normally descended testicle was removed using the method described. It is concluded that the present method of castration will only be successful when surgery is carried out under strictly aseptic conditions.

[Radiological and clinical considerations on navicular disease (author's transl)]. / Radiologisch-klinische beschouwingen betreffende podotrochleose.

The radiological and clinical interpretation of alterations of the navicular bone, the interaction of radiological and clinical symptoms in relation to the age of the animal, the influence of work-load on this interaction and the possibility of predicting navicular disease at an early stage are discussed. The discussion is based on experience in a study of 130 horses.