MAGNETIC RESONANCE IMAGING OF SUBARTICULAR BONE MARROW LESIONS IN DOGS WITH STIFLE LAMENESS

A bone bruise is a magnetic resonance (MR) imaging sign thought to signify acute traumatic microfracture of trabecular bone with hemorrhage and edema in the marrow that may occur without grossly visible disruption of the adjacent cortices or overlying cartilage. In approximately 75% of people with acute anterior-cruciate ligament tears, bone bruises are detected in characteristic locations within the femur and tibia and are best seen as high-signal lesions using fat-suppression sequences. We questioned whether this is a component of naturally acquired stifle lameness in dogs and obtained short-tau inversion recovery (STIR) images of six dogs with stifle lameness. High-signal STIR lesions were detected in five of six (83%) dogs and eight of 12 (67%) limbs. We observed these lesions deep to the intercondylar fossa of the femur and intercondylar eminence of the tibia, which are atypical locations in people. High-signal STIR lesions were detected in dogs with only synovitis, partial tear of the cranial cruciate ligament (CCL) and complete tear of the CCL. One of these lesions was seen in the lateral tibial condyle, a typical location in humans with acute anterior cruciate ligament tear. As the MR imaging appearance of stress fractures and bone bruises are similar, and the high-signal STIR lesions are at attachment sites of the CCL, this finding may be due to stress disease or other unknown causes, rather than bone bruising. High-signal STIR lesions may be a common sign in naturally acquired canine stifle disease, but the pathogenesis, prognostic and diagnostic values need further investigation.     

SKELETAL LESIONS OF HISTIOCYTIC SARCOMA IN NINETEEN DOGS

The purpose of this study was to describe the clinical and radiographic findings in dogs with bone lesions secondary to histiocytic sarcoma. Nineteen dogs with radiographically identified bone lesions that were histologically diagnosed as histiocytic sarcoma were assessed. The medical records, all available radiographs and histologic sections were reviewed retrospectively. Dogs were subcategorized into localized or disseminated histiocytic sarcoma groups. Golden Retrievers or Rottweilers greater than 5 years of age, with a history of lameness or neurologic deficits localized to the spinal cord was the most common presentation. Fifteen of 19 dogs had a radiographically detectable soft tissue mass associated with bone destruction. The bone lesions had aggressive characteristics and the sites of involvement included periarticular bones (n = 11), vertebrae (n = 6), proximal humerus (n = 5), and rib (n = 2). Fifteen of 19 dogs had disseminated histiocytic sarcoma, and four had localized histiocytic sarcoma. All Rottweilers had disseminated histiocytic sarcoma. Histiocytic sarcoma should be considered as a differential diagnosis for aggressive periarticular, vertebral, or proximal humeral bone lesions identified on radiographs. The index of suspicion should be increased in greater than 5-year-old Golden Retrievers and Rottweilers when a soft tissue mass is associated with the bone lesion on radiographs or myelography. Bone involvement with histiocytic sarcoma, and the Rottweiler breed, was associated with the disseminated form of the disease.     

EFFECTS OF MEASUREMENT OF PLASMA ACTIVITY INPUT ON NORMALIZATION OF GLOMERULAR FILTRATION RATE TO PLASMA VOLUME IN DOGS

Glomerular filtration rate (GFR) normalized to body fluid volumes to adjust for differing body size and conformation is more physiologically correct than a relationship with body weight (BW). GFR can be normalized to plasma volume by a renographic method that uses the Rutland-Patlak plot with plasma activity and kidney activity inputs. A plasma time-activity curve is obtained from a region of interest (ROI) of the left ventricle (LV), the size of which is in theory not critical. The aims of the study were to evaluate the effect of different LV ROI sizes, the effect of extravascular activity in the thorax over the LV ROI, and different time intervals for the semilogarithmic LV plot. Seventy-two scintigrams were used, with three different-sized automatic and a manual LV ROI, all with and without subtracting extravascular activity, and with LV curve time intervals of 30-120 s and 60-240 s. GFR/plasma volume was not affected by LV ROI sizes but significantly affected by extravascular activity subtraction and different time intervals. Subtracting extravascular activity from the LV ROI did not improve precision, but increased variability caused by different LV ROI sizes and time intervals chosen for the LV plot. The ROI for measuring extravascular activity apparently contained a considerable and variable intravascular component, which when subtracted, created noisy and unreliable LV curves. Manual LV ROI, without extravascular subtraction, and a time interval for LV input between 1 and 4 min are recommended as they gave the least variability determined by statistical analysis. With these methods, normal individual GFR/plasma volume in normal beagle dogs was 29.2 +/- 6.5 ml/min/l.     

Mid-metacarpal Deep Digital Flexor Tenotomy in the Management of Refractory Laminitis in Horses

Deep digital flexor tendon transection at the mid-metacarpus was performed in 20 horses with severe acute or chronic laminitis that was not responsive to conventional treatment. Sixteen horses improved within 72 hours, one horse worsened, and two horses were unaffected by the surgery. Eleven horses survived less than 1 month after surgery and six horses survived longer than 6 months. Three horses surviving longer than 6 months have remained lame and no horse has returned to athletic performance. Transection of the deep digital flexor tendon at the mid-metacarpus may decrease the pain associated with the acute refractory stage of laminitis and may be useful as an immediate salvage procedure; however, despite the early clinical improvement observed after tenotomy, the survival rate of affected horses may not be altered.     

Comparison of four dog diets (including nitrogen balance study)

Four pairs of Beagle dogs received in rotation, a specially prepared purified diet in powder form (reference diet), a semi-solid (SS) diet and two complete dry diets in expanded-pellet form (Dry-S and Dry-P). Finally, all dogs received a nitrogen-free diet. The diets were offered in equi-caloric quantities (175 kcal/kg body weight/day) and consumed for 14-day periods. Nitrogen balance was determined during the last 5 days of each period. Clinical observations (clinical signs, body weight, food and water consumption) revealed no differences between the semi-solid and two dry diets. On the reference diet, however; food consumption was poor, no weight was gained and water intake was increased. Nitrogen balance studies revealed that:

• (i). The relative biological values (BV) of the reference diet protein (casein) and that in the Dry-S diet were similar and greater than those of the other two products. The value for the Dry-S diet (BV = 58) was significantly greater than that on the Dry-P diet (BV = 50) at almost the 5 per cent level of probability.
• (ii). The apparent digestibility of nitrogen was greatest on the reference diet, however any advantage that this may have entailed was reversed by the low food intake, so that significantly greater quantities of nitrogen were absorbed by the same dogs, when offered the dry diets (0–1 per cent level of significance) and also the semi-solid diet (5 per cent level of significance).
• (iii). Nitrogen retention within the body was significantly greater on the Dry-S diet, but analysis of covariance showed that the group differences were entirely dependent on the amounts of nitrogen absorbed.

Résumé. Quatre paires de chiens Beagles reqoivent tour à tour un régime spécialement purifié préparé sous forme de poudre (régime de référence), un régime semi-solide (SS) et dew régimes complètement secs, sous forme de tablettes (Dry-S et Dry-P). Puis, tous les chiens reçoivent un régime totalement dépourvu d'azote. La nourriture était administrée en des quantités équicaloriques (175 calories/kg de poids corporel et par jour) et poursuivie pendant 14 jours. Le bilan azoté était déterminé au cours des 5 derniers jours de chaque période. L'observation clinique (signes cliniques, poids, consommation de nourriture et doses) n'a montré aucune différence entre le régime semi-solide et les deux régimes secs; cependant, avec le régime de référence, la consommation de nourriture était réduite, celle de l'eau augmentée, et le poids est resté stationnaire. L'étude du bilan azoté a donné les résultats suivants:

• (i). Les valeurs biologiques relatives (BV) concernant la protéine du régime de référence (caséine) et celle du régime Dry-S étaient similaires et supérieures à ce qui était observé avec les deux autres produits. Les valeurs pour le régime Dry-S (BV = 58) étaient significativement plus grandes que celles du regime Dry-P (BV = 50) à un niveau de presque 5% de probabilité.
• (ii). La digestibilité apparente de l'azote était la plus grande avec le régime de référence, cependant les avantages qui pouvaient en être tirés étaient réduits par la faible prise de nourriture, d'où absorption de quantités significativement plus grandes d'azote chez le meme chien soumis ultérieurement au régime sec (niveau de signification = 0,1%) et aussi au régime semi-solide (niveau de signification = 5%).
• (iii). La retention azotée dans l'organisme était significativement plus grande avec le régime Dry-S, mais l'analyse des covariances a montré que les différences de groupes dépendaient totalement des quantités d'azote absorbées.

Zusammenfassung. Vier Paare von Beaglehunden erhielten in planmässigem Wechsel ein besonders hergestelltes gereinigtes Futter in Pulverform (Reference Diet), ein halbfestes Futter (SS) und zwei völlig trockene Futtertypen in Form expandierter Pellets (Dry-S und Dry-P). Schliesslich erhielten alle Hunde ein stickstomreies Futter. Die Futtertypen wurden den Tieren in kalorisch gleichwertigen Mengen (175 cal/kg Körpergewicht/Tag) geboten und jeweils 14 Tage lang gefressen. Während der letzten 5 Tage jeder Periode wurde die Stickstoffbilanz bestimmt. Die klinischen Beobachtungen (klinische Zeichen, Körpergewicht, Futter- und Wasserverbrauch) ergaben keine Unterschiede zwischen dem halbfesten Futter und den zwei trockenen Futtertypen. Bei der Reference Diet war jedoch der Futterverbrauch gering, es erfolgte keine Gewichtszunahme und der Wasserverbrauch war erhöht. Die Stickstoff bilanzbestimmungen zeigten, dass:

• (i). Die relativen biologischen Werte (BW) des Reference-Diet-Proteins (Casein) und des Proteins im Dry-S-Futter ähnlich und grösser als die der beiden anderen Produkte waren. Der Wert für das Dry-S-Futter (BW = 58) war wesentlich grösser als der für das Dry-P-Futter (BW = 50) bei fast 5% Probabilität.
• (ii). Die scheinbare Verdaulichkeit des Stickstoffs war am grössten bei der Reference Diet, jedoch wurde jeder dadurch mögliche Vorteil durch die geringe Futteraufnahme aufgehoben, so dass die gleichen Hunde wesentlich grössere Stickstoffmengen absorbierten, wenn sie die trockenen Futtertypen erhielten (0,1% Signifikanz) oder auch das halbfeste Futter (5% Signifikanz).
• (iii). Die Stickstoffspeicherung im Körper war beim Dry-S-Futter wesentlich grösser, aber die Kovarianzanalyse zeigte, dass die Gruppenunterschiede völlig von den absorbierten Stickstoffmengen abhingen.

     

Comparison of four dog diets (including nitrogen balance study)

Four pairs of Beagle dogs received in rotation, a specially prepared purified diet in powder form (reference diet), a semi-solid (SS) diet and two complete dry diets in expanded-pellet form (Dry-S and Dry-P). Finally, all dogs received a nitrogen-free diet. The diets were offered in equi-caloric quantities (175 kcal/kg body weight/day) and consumed for 14-day periods. Nitrogen balance was determined during the last 5 days of each period. Clinical observations (clinical signs, body weight, food and water consumption) revealed no differences between the semi-solid and two dry diets. On the reference diet, however; food consumption was poor, no weight was gained and water intake was increased. Nitrogen balance studies revealed that:

• (i). The relative biological values (BV) of the reference diet protein (casein) and that in the Dry-S diet were similar and greater than those of the other two products. The value for the Dry-S diet (BV = 58) was significantly greater than that on the Dry-P diet (BV = 50) at almost the 5 per cent level of probability.
• (ii). The apparent digestibility of nitrogen was greatest on the reference diet, however any advantage that this may have entailed was reversed by the low food intake, so that significantly greater quantities of nitrogen were absorbed by the same dogs, when offered the dry diets (0–1 per cent level of significance) and also the semi-solid diet (5 per cent level of significance).
• (iii). Nitrogen retention within the body was significantly greater on the Dry-S diet, but analysis of covariance showed that the group differences were entirely dependent on the amounts of nitrogen absorbed.

Résumé. Quatre paires de chiens Beagles reqoivent tour à tour un régime spécialement purifié préparé sous forme de poudre (régime de référence), un régime semi-solide (SS) et dew régimes complètement secs, sous forme de tablettes (Dry-S et Dry-P). Puis, tous les chiens reçoivent un régime totalement dépourvu d'azote. La nourriture était administrée en des quantités équicaloriques (175 calories/kg de poids corporel et par jour) et poursuivie pendant 14 jours. Le bilan azoté était déterminé au cours des 5 derniers jours de chaque période. L'observation clinique (signes cliniques, poids, consommation de nourriture et doses) n'a montré aucune différence entre le régime semi-solide et les deux régimes secs; cependant, avec le régime de référence, la consommation de nourriture était réduite, celle de l'eau augmentée, et le poids est resté stationnaire. L'étude du bilan azoté a donné les résultats suivants:

• (i). Les valeurs biologiques relatives (BV) concernant la protéine du régime de référence (caséine) et celle du régime Dry-S étaient similaires et supérieures à ce qui était observé avec les deux autres produits. Les valeurs pour le régime Dry-S (BV = 58) étaient significativement plus grandes que celles du regime Dry-P (BV = 50) à un niveau de presque 5% de probabilité.
• (ii). La digestibilité apparente de l'azote était la plus grande avec le régime de référence, cependant les avantages qui pouvaient en être tirés étaient réduits par la faible prise de nourriture, d'où absorption de quantités significativement plus grandes d'azote chez le meme chien soumis ultérieurement au régime sec (niveau de signification = 0,1%) et aussi au régime semi-solide (niveau de signification = 5%).
• (iii). La retention azotée dans l'organisme était significativement plus grande avec le régime Dry-S, mais l'analyse des covariances a montré que les différences de groupes dépendaient totalement des quantités d'azote absorbées.

Zusammenfassung. Vier Paare von Beaglehunden erhielten in planmässigem Wechsel ein besonders hergestelltes gereinigtes Futter in Pulverform (Reference Diet), ein halbfestes Futter (SS) und zwei völlig trockene Futtertypen in Form expandierter Pellets (Dry-S und Dry-P). Schliesslich erhielten alle Hunde ein stickstomreies Futter. Die Futtertypen wurden den Tieren in kalorisch gleichwertigen Mengen (175 cal/kg Körpergewicht/Tag) geboten und jeweils 14 Tage lang gefressen. Während der letzten 5 Tage jeder Periode wurde die Stickstoffbilanz bestimmt. Die klinischen Beobachtungen (klinische Zeichen, Körpergewicht, Futter- und Wasserverbrauch) ergaben keine Unterschiede zwischen dem halbfesten Futter und den zwei trockenen Futtertypen. Bei der Reference Diet war jedoch der Futterverbrauch gering, es erfolgte keine Gewichtszunahme und der Wasserverbrauch war erhöht. Die Stickstoff bilanzbestimmungen zeigten, dass:

• (i). Die relativen biologischen Werte (BW) des Reference-Diet-Proteins (Casein) und des Proteins im Dry-S-Futter ähnlich und grösser als die der beiden anderen Produkte waren. Der Wert für das Dry-S-Futter (BW = 58) war wesentlich grösser als der für das Dry-P-Futter (BW = 50) bei fast 5% Probabilität.
• (ii). Die scheinbare Verdaulichkeit des Stickstoffs war am grössten bei der Reference Diet, jedoch wurde jeder dadurch mögliche Vorteil durch die geringe Futteraufnahme aufgehoben, so dass die gleichen Hunde wesentlich grössere Stickstoffmengen absorbierten, wenn sie die trockenen Futtertypen erhielten (0,1% Signifikanz) oder auch das halbfeste Futter (5% Signifikanz).
• (iii). Die Stickstoffspeicherung im Körper war beim Dry-S-Futter wesentlich grösser, aber die Kovarianzanalyse zeigte, dass die Gruppenunterschiede völlig von den absorbierten Stickstoffmengen abhingen.

     

Uterine glycogen metabolism in mink during estrus,embryonic diapause and pregnancy

We have determined uterine glycogen content, metabolizing enzyme expression and activity in the mink, a species that exhibits obligatory embryonic diapause, resulting in delayed implantation. Gross uterine glycogen concentrations were highest in estrus, decreased 50% by diapause and 90% in pregnancy (P ≤ 0.05). Endometrial glycogen deposits, which localized primarily to glandular and luminal epithelia, decreased 99% between estrus and diapause (P ≤ 0.05) and were nearly undetectable in pregnancy. Glycogen synthase and phosphorylase proteins were most abundant in the glandular epithelia. Glycogen phosphorylase activity (total) in uterine homogenates was higher during estrus and diapause, than pregnancy. While glycogen phosphorylase protein was detected during estrus and diapause, glycogen synthase was almost undetectable after estrus, which probably contributed to a higher glycogenolysis / glycogenesis ratio during diapause. Uterine glucose-6-phosphatase 3 gene expression was greater during diapause, when compared to estrus (P ≤ 0.05) and supports the hypothesis that glucose-6-phosphate resulting from phosphorylase activity was dephosphorylated in preparation for export into the uterine lumen. The relatively high amount of hexokinase-1 protein detected in the luminal epithelia during estrus and diapause may have contributed to glucose trapping after endometrial glycogen reserves were depleted. Collectively, our findings suggest to us that endometrial glycogen reserves may be an important source of energy, supporting uterine and conceptus metabolism up to the diapausing blastocyst stage. As a result, the size of uterine glycogen reserves accumulated prior to mating may in part, determine the number of embryos that survive to the blastocyst stage, and ultimately litter size.