Chinese hamster ovary cell lysosomes rapidly exchange contents.

We have used cell fusion to address the question of whether macromolecules are rapidly exchanged between lysosomes. Donor cell lysosomes were labeled by the long-term internalization of the fluid-phase pinocytic markers, invertase (sucrase), Lucifer Yellow, FITC-conjugated dextran, or Texas red-conjugated dextran. Recipient cells contained lysosomes swollen by long-term internalization of dilute sucrose or marked by an overnight FITC-dextran uptake. Cells were incubated for 1 or 2 h in marker-free media before cell fusion to clear any marker from an endosomal compartment. Recipient cells were infected with vesicular stomatitis virus as a fusogen. Donor and recipient cells were co-cultured for 1 or 2 h and then fused by a brief exposure to pH 5. In all cases, extensive exchange of content between donor and recipient cell lysosomes was observed at 37 degrees C. Incubation of cell syncytia at 17 degrees C blocked lysosome/lysosome exchange, although a "priming" process(es) appeared to occur at 17 degrees C. The kinetics of lysosome/lysosome exchange in fusions between cells containing invertase-positive lysosomes and sucrose-positive lysosomes indicated that lysosome/lysosome exchange was as rapid, if not more rapid, than endosome/lysosome exchange. These experiments suggest that in vivo the lysosome is a rapidly intermixing organellar compartment.

Differences in clinical grading associated with instructor status.

PURPOSE: The purpose of this study was to determine whether the clinical evaluation of pre-doctoral students is associated with instructor status. The hypothesis was that there would be no association between instructor status and clinical evaluation grades. MATERIALS AND METHODS: Retrospective analysis of pre-doctoral clinical evaluations for class II amalgams, class III composites, and periodontal scaling and root planing was performed. The grade averages were based on a rank scale. Descriptive statistics were computed to summarise the predictor and outcome variables. Bivariate statistics were computed to evaluate any associations between the predictors and outcomes. Multiple linear regression models were computed to evaluate the simultaneous effects of multiple predictors on clinical evaluations. RESULTS: The study sample consisted of 238 class II amalgams, 246 class III composites, and 675 scaling and root planings which occurred between August 2003 and June 2005. The procedure averages for these procedures were 1.8 +/- 0.67, 1.8 +/- 0.66 and 2.1 +/- 0.56 respectively. The management averages were 2.0 +/- 0.63, 1.5 +/- 0.58 and 1.4 +/- 0.54 respectively. In bivariate analyses, faculty status was associated with treatment averages for all three procedures. CONCLUSIONS: Faculty status was associated with treatment score for all three procedures evaluated. Full-time faculty gave the best grades for restorative procedures. For periodontal procedures, part-time faculty gave the best grades. More studies are warranted to elucidate the nature behind these differences.

Effects of exercise vs experimental osteoarthritis on imaging outcomes.

OBJECTIVE: To identify changes in imaging outcomes in a controlled model of osteoarthritis (OA) vs exercise. METHOD: Sixteen 2-year-old horses were randomly assigned to an exercise control (n=8) or an exercise OA (n=8) group. All horses had middle carpal joints arthroscopically explored and an osteochondral fragment was induced in one middle carpal joint of the OA group. All horses were treadmill exercised for the duration of the study (91 days). Clinical, radiographic, nuclear scintigraphic, computed tomographic and magnetic resonance imaging (MRI) examinations were performed and outcomes of these were compared between groups. Imaging results were correlated to clinical, biomarker and gross pathologic results. RESULTS: The OA group had significant increases in clinical outcomes and most imaging parameters. Specifically, the OA group showed significant increases in radiographic lysis and nuclear scintigraphic uptake. There was very little change in subchondral bone density, but a significant change in subchondral bone edema. Radiographic lysis, radial carpal bone edema and nuclear scintigraphy were strongly correlated with clinical changes and radial carpal bone edema was strongly correlated with changes in Type I and Type II collagen found in the synovial fluid. CONCLUSIONS: OA induced significant changes in imaging parameters beyond the adaptation seen with exercise. Bone edema detected with MRI was closely correlated with collagen biomarkers detected in the synovial fluid.

Response of aorta and branch arteries to experimental intraoperative irradiation.

Injury to the aorta was evaluated in dogs 2 and 5 years after fractionated irradiation (EBRT), intraoperative irradiation (IORT) or a combination. Doses greater than 20 Gy IORT combined with 50 Gy EBRT given in 2 Gy fractions or 30 Gy IORT alone were accompanied by a significant risk of aneurysms or large thrombi as determined at necropsy 4 to 5 years following irradiation. Narrowing of the aorta as detected by aortography occurred at 5 years but was not detected earlier. The ED50 for aortic narrowing was 38.8 Gy IORT and 31 Gy IORT plus 50 Gy EBRT. The ED50 for branch artery injury was 24.8 Gy IORT alone and 19.4 Gy IORT plus 50 Gy EBRT. The difference in ED50s for IORT alone and IORT plus EBRT indicates that the contribution of the EBRT dose in terms of an IORT dose for aortic narrowing was 7.8 Gy and for branch artery injury was 5.4 Gy. The ED50 for incidence of small thrombi in the aorta was about 29 Gy for IORT alone and 23.5 Gy for IORT combined with EBRT. Fibrous thickening of the adventitia was measured and the effect of the 50 Gy EBRT component of a combination of EBRT and IORT was determined to be equivalent to 10 to 12 Gy IORT. Based on the various estimates, IORT doses of 10-15 Gy have an effect of 5 times or greater the amount given in 2 Gy fractions. At all EBRT doses and at lower IORT doses the intima was greatly thickened. At IORT doses of 20 Gy or above there was a dose related decrease in intimal thickness to near normal values. This was probably due to cell killing or inhibition of intimal proliferation that predominated at higher doses. Although the risk of serious vascular complications appears low following IORT of humans, this may be due to short observation times and the fact that IORT doses currently used are usually 20 Gy or less; this may be near the tolerance for late response of larger arteries. Only one dog in this study had complete rupture of the aorta causing death. Five other dogs at high IORT doses had near ruptures of the aorta but were clinically normal.

Ureteral injury following experimental intraoperative radiation.

Beagle dogs were randomized to receive a range of total dose delivered in three different protocols. Sixteen dogs received external beam radiation therapy (EBRT), 32 dogs received intraoperative irradiation (IORT), and 32 dogs received combinations of external beam radiation therapy and intraoperative irradiation. A sublumbar field was irradiated which always included the left ureter. Dogs were observed for 5 years; sequential excretory urograms were done at 6 months, and 1 and 5 years. Morphometric analysis of tissues were also done. The canine ureter tolerated 17.5 Gy intraoperative irradiation with no evidence of injury and 25 Gy intraoperative irradiation with a low probability of injury. The ED50 for radiographic abnormalities was 32.9 Gy. When 50 Gy external beam radiation therapy was given prior to intraoperative irradiation, the ureter tolerated 10 Gy intraoperative irradiation with no evidence of injury and 17.5 Gy with a low probability of injury. The ED50 was 29 Gy intraoperative irradiation after EBRT. The external beam radiation therapy had little effect on the ureter when given alone or prior to intraoperative irradiation. Clinical signs of renal disease occurred only in dogs who had received bilateral ureteral irradiation intraoperatively at doses of 32.5 Gy intraoperative irradiation and 25 Gy intraoperative irradiation after external beam radiation therapy. Histologic evidence suggests that the chronic injury of the ureter expressed at 5 years is of vascular etiology. The early injury may be due to ulceration of the epithelium.

The role of subchondral bone in joint disease: a review.

Subchondral bone plays a role in the pathogenesis of osteochondral damage and osteoarthritis in horses and humans. Osteochondral fragmentation and fracture, subchondral bone necrosis and osteoarthritis are common diseases in athletic horses, and subchondral bone is now thought to play an integral role in the pathogenesis of these diseases. There have been numerous research efforts focused on articular cartilage damage and its pathogenesis, yet comparatively little effort focused on subchondral bone pathology or the coordinated disease states of the osteochondral tissues. The purpose of this report is to review the current understanding of osteochondral disease in all species and its application to equine research and practice. It can be concluded from this review that our current understanding of osteochondral disease is based on clinical and pathological sources; and that the lack of information about joint tissue adaptation and disease has hampered objective studies of osteochondral tissues.

Radiographic changes in Thoroughbred yearlings. Part 1: Prevalence at the time of the yearling sales.

REASONS FOR PERFORMING STUDY: Radiography in presale examinations of TB yearlings has become standard practice in recent years. OBJECTIVES: To describe the prevalence and distribution of radiographic changes in the fetlocks, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings in central Kentucky when these joints were examined as part of routine pre- and post sale evaluations. METHODS: Horses subjected to radiographs included the fore (n = 1127) and hind (n = 1102) fetlocks, carpi (n = 1130), tarsi (n = 1101), stifles (n = 660) and fore feet (n = 300). Radiographic changes were categorised by location and type of change present (e.g. lucency, fragment) for each series. RESULTS: In the fore fetlocks 1.6% had fragmentation of the proximal dorsal first phalanx and 0.5% fragmentation of the proximal palmar aspect. In the hind fetlocks 5.9% had fragmentation at the plantar aspect and 3.3% fragmentation dorsally. Lucencies, fragments or loose bodies were detected at the dorsal aspect of the distal third metacarpus in 2.8% and, at the same location on the third metatarsus, 3.2%. Most yearlings (98%) had vascular channels in the proximal sesamoid bones and irregular vascular channels (> 2 mm wide or with nonparallel sides) were more common (79%) than regular vascular channels (56%). The intermediate ridge of the distal tibia was the most common location for fragmentation in the tarsus (4.4%). CONCLUSIONS: While some radiographic changes, e.g. vascular channels in proximal sesamoid bones, are very common in Thoroughbred yearlings, others, e.g. fragmentation or subchondral lucency within joints are quite rare usually affecting less than 5% of the population. POTENTIAL RELEVANCE: Veterinarians should expect to find radiographic changes in Thoroughbreds presented for examination prior to the yearling sales. The rarity of some changes thought to affect soundness or racing performance will make further invesigation of these conditions in horses without clinical signs more difficult.

Radiographic changes in Thoroughbred yearlings. Part 2: Associations with racing performance.

REASONS FOR PERFORMING STUDY: Although the radiographic examination of yearlings has become commonplace at some large Thoroughbred sales, there are few data to support the decisions facing veterinarians who are asked to evaluate future racing potential. OBJECTIVES: To identify radiographic changes in the fetlocks, proximal sesamoid bones, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings associated with future racing performance during ages 2 and 3 years. METHODS: Radiographs from routine pre- and post sale examinations of 1162 yearlings were used to identify individual radiographic changes in sale yearlings. Starting a race, the percent of starts placed, money earned and earnings per start were used to assess racing performanceand examined for associations with the radiographic changes observed. RESULTS: Overall 946 (81%) yearlings started at least one race during ages 2 or 3 years. Fourteen of 24 (58%) yearlings with moderate or extreme palmar supracondylar lysis of the third metacarpus, 8 of 14 (57%) of those with enthesophyte formation on the proximal sesamoid bones and 19 of 30 (63%) of those with dorsal medial intercarpal joint disease started a race. The odds of starting a race when age 2 or 3 years were 3 times lower for yearlings with these changes (P < 0.01) compared with yearlings that did not have these changes. Twenty-five of 36 (69%) yearlings with proximal dorsal fragmentation of the first phalanx in the hind fetlock started a race and these yearlings were also less likely (OR = 0.51, P = 0.07) to start a race. Yearlings with enthesophyte formation on hind proximal sesamoid bones placed in a smaller percentage of starts (16%, P = 0.01) earned less money (987 US dollars, P = 0.02) and had lower earnings per start (252 US dollars, P = 0.03) compared to starters without this change. CONCLUSIONS: Although many of the changes observed on radiographs of sale yearlings do not appear to influence future racing performance, some are associated with reduced performance. POTENTIAL RELEVANCE: The results of this study are best applied in parallel with the clinical impressions of veterinarians experienced in examining radiographs of sale yearlings. Some findings support those established in the literature as incidental findings and others suggest new areas for concern not previously reported as a problem in Thoroughbred sale yearlings.

Diagnosis of cauda equina abnormalities by using electromyography, discography, and epidurography in dogs.

Electromyography (EMG), L7-S1 discography and epidurography were investigated in 15 dogs with clinical signs of cauda equina dysfunction and in 7 control dogs without such clinical signs. Electromyography of paraspinal and pelvic limb muscles was done in 13 of 15 affected dogs. An L7-S1 discogram followed by an epidurogram was performed in all 22 dogs using 20% iopamidol. Results of discograms, epidurograms, and gross necropsy examinations were normal in six of seven control dogs. The one dog in which these studies were abnormal had a mild L7-S1 disc protrusion that did not result in nerve root compression at necropsy. Electromyographic analysis was 100% accurate in predicting the presence or absence of cauda equina disease. None of the results of discograms were falsely negative. Twelve of 15 discograms in clinically affected dogs indicated dorsal disc protrusion, but 2 of these protrusions were found to be noncompressive at surgery (13% error). Abnormal epidurograms occurred in 9 of 15 clinically affected dogs. There was one false positive and two false negatives (20% error). Electromyography was a sensitive screening technique for the presence of cauda equina disease. Discography may be more sensitive for detection of L7-S1 disc protrusion than epidurography. An abnormal radiographic contrast study of the cauda equina may only be useful when combined with an abnormal EMG.

A syndrome resembling lymphomatoid granulomatosis in the dog.

Lymphomatoid granulomatosis (LYG) was diagnosed in seven dogs. Most of the affected dogs were young to middle-aged, and there was no breed or sex predilection. Basophilia was detected in six of the seven dogs. Radiographic abnormalities included lung lobe consolidation or pulmonary mass lesions, as well as abnormally large tracheobronchial lymph nodes. Histologic changes included angiocentric and angiodestructive pulmonary infiltrates characterized by large lymphoreticular and plasmacytoid cells as well as normal lymphocytes, eosinophils, and plasma cells. Five dogs were treated with combination chemotherapy, and three had a complete response to treatment.

Ultrasonographic determination, in vitro and in vivo, of canine gallbladder volume, using four volumetric formulas and stepwise-regression models.

Twelve resected canine gallbladders (in vitro) and the gallbladder in each of 14 dogs (in vivo) were ultrasonographically examined. Gallbladder volume was calculated from ultrasonographically measured geometric dimensions, using 4 volumetric model formulas: cone, ellipse, biplanar ellipse, and prolate ellipse. Calculated volume was compared with true gallbladder volume, as measured by water displacement. All examined models for calculation of gallbladder volume were closely associated with true gallbladder volume (P < 0.005), and all models provided accurate predictions of true gallbladder volume (r2 > 0.80). Calculated volumes can be corrected mathematically by use of the regression coefficient and constant for each model. Body weight was not significantly associated with gallbladder volume in any of the models considered. Use of ultrasonography to accurately measure gallbladder volume could be combined with synthetic cholecystokinin-stimulated gallbladder emptying to provide information about biliary function and patency in icteric animals. Such information could aid the clinical decision between surgical or medical treatment. Correction of calculated volumes would not be necessary in association with induced emptying studies, because volume change is more important than absolute volume.

Clinical effects of exercise on subchondral bone of carpal and metacarpophalangeal joints in horses.

OBJECTIVE: To determine effects of treadmill exercise on subchondral bone of carpal and metacarpophalangeal joints of 2-year-old horses. ANIMALS: 12 healthy 2-year-old horses. PROCEDURE: Horses were randomly assigned to the control (n = 6) or exercised (6) groups. Horses in the exercised group ran on a high-speed treadmill 5 d/wk for 6 months. Horses in the control group were hand walked for the same amount of time. Results of clinical, radiographic, nuclear scintigraphic, and computed tomographic examinations, and serum and synovial concentrations of biochemical markers of bone metabolism were compared between groups. RESULTS: Exercised horses were significantly lamer at the end of the study than control horses. Radionuclide uptake in the metacarpal condyles, but not in the carpal joints, was greater in exercised horses, compared with control horses. Exercised horses also had a higher subchondral bone density in the metacarpal condyles than control horses, but such differences were not detected in the carpal bones. CONCLUSIONS AND CLINICAL RELEVANCE: None of the diagnostic techniques evaluated was sufficiently sensitive to detect all osteochondral damage. Computed tomography and computed tomographic osteoabsorptiometry were superior to conventional radiography for detecting small osteochondral fragments. Nuclear scintigraphy was a sensitive indicator of subchondral bone change but lacked specificity for describing lesions and discerning normal bone remodeling from damage. Newer techniques such as computed tomography may help clinicians better diagnose early and subtle joint lesions in horses prior to development of gross joint damage.

Comparison of radiography, magnetic resonance imaging, and surgical findings in dogs with elbow dysplasia.

OBJECTIVE: To describe the magnetic resonance imaging (MRI) appearance of medial coronoid process and humeral condyle lesions in dysplastic cubital joints and to compare survey radiography and MRI for evaluation of fragmented medial coronoid process (FMCP) and lesions of the medial aspect of the humeral condyle (MAHC). ANIMALS: 18 dogs with elbow dysplasia. PROCEDURE: Radiography of 22 cubital joints was performed. The 22 joints then underwent MRI. The scans were evaluated with regard to the shape and signal of the coronoid process; articular cartilage change, subchondral bone disruption of the MAHC. Surgical findings were used as the standard to calculate accuracy, sensitivity, specificity, and positive- and negative-predictive values for specific diagnosis of FMCP (free fragment) and lesions of the MAHC. RESULTS: At surgery, 31.8% of the joints had FMCP (free), 36.4% had nondisplaced unmineralized coronoid process, and 27.2% had nondisplaced mineralized coronoid process. Eleven joints had lesions of the MAHC, and wear lesions were observed in 41% of the joints. On radiography, FMCP (free) was visualized in 9% of the joints and lesions of the MAHC were observed in 23%. MRI had the highest accuracy (95.5%), sensitivity (100%), and negative-predictive value (100%) for detection of FMCP (free), and had accuracy (91%), sensitivity (87.5%), specificity (92.5%), and positive (87.5%)- and negative (92.5%)-predictive values for detection of nondisplaced unmineralized coronoid process. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with radiography, MRI was useful for detection of nondisplaced unmineralized coronoid process; images consistently correlated with surgical findings. The technique is accurate and especially useful when radiographic findings are inconclusive.

Effects of intramedullary injection of methiodal and lidocaine on spinal cords of dogs.

A solution of methiodal sodium (20%) and lidocaine HCl (0.20%) was given by intramedullary injection into the lumbar spinal cords of 12 anesthetized dogs (group I). Two control groups of 12 dogs each were subjected to needle placement only or were given 5% dextrose. The results showed that both solutions given by intramedullary injection caused severe spinal cord malacia and cavitation in 2 group I dogs and in 1 group III dog.

Magnetic resonance arthrography of the cubital joint in dogs affected with fragmented medial coronoid processes.

OBJECTIVE: To evaluate efficacy of intra-articular injection of gadolinium tetra- azacyclododecane tetraacetic acid (gadolinium-DOTA) for delineating fragmented medial coronoid processes (FMCP) and lesions on the medial aspect of the humeral condyle (MAHC). SAMPLE POPULATION: 14 cubital joints in 9 dogs. PROCEDURE: Magnetic resonance imaging (MRI) was performed with and without intra-articular injection of a solution of 2 mmol of gadolinium-DOTA/L. Arthrographic images obtained after injection of contrast medium were compared with those obtained without contrast medium. Evidence of contrast medium around or in the medial coronoid process and infiltration of contrast medium in subchondral bone lesions was recorded. Twenty-four hours after imaging, arthroscopy was performed, and lesions detected were correlated with results of MRI. RESULTS: An abnormal coronoid process was diagnosed in 13 of 14 joints. A fragmented process (free) was seen in 7 of 14 joints; nondisplaced mineralized medial (in situ) coronoid processes were evident in 4 joints; and nondisplaced unmineralized medial coronoid processes were evident in 2 joints. Lesions on the MAHC were diagnosed in 4 of 12 joints. In 5 joints, a hyperintense signal resulted from contrast medium that infiltrated between the fragmented process and ulna. In 2 joints, contrast medium did not infiltrate completely around the process and was stopped by an isointense structure (ie, abnormal cartilage). Subchondral bone lesions were enhanced by use of contrast medium. CONCLUSION AND CLINICAL RELEVANCE: Use of arthrography enabled us to identify FMCP easily, but did not provide important additional information about changes on the medial coronoid process, compared with MRI performed without contrast medium.

Comparison of computed tomography and radiography for detecting changes induced by malignant nasal neoplasia in dogs.

The ability of computed tomography and radiography to detect changes associated with nasal neoplasia was compared in dogs. Eighteen areas or anatomic structures were evaluated in 21 dogs for changes indicative of neoplasia. Computed tomography was superior (P < or = 0.05) to radiography for detecting changes in 14 of 18 areas. Radiography was not superior for detecting changes in any structure or area. Computed tomography reveals vital information not always detected radiographically to assist in providing a prognosis and in planning treatment for nasal neoplasms in dogs.

Periosteal transection and stripping for treatment of angular limb deformities in foals: clinical observations.

Correction was attempted in 27 foals (41 limbs) with angular deformities at the carpal region (35 limbs), metatarsophalangeal region (5 limbs) and distal end of the tibia (1 limb) by hemicircumferential transection of the periosteum (HCTP) and periosteal stripping (PS). Successful outcome was determined by straight limbs and soundness, which was achieved in 81.5% of the cases, with 60% of the horses in performance training. Follow-up evaluation for all foals was completed at various times after physiologic closure of the physes. In none of the limbs was the deformity overcorrected. Owners of foals with carpal region deviations corrected by means of HCTP and PS were satisfied with the result. The cosmetic appearance of the surgical site was excellent. The HCTP and PS adequately corrected greater degrees of carpal region deformity and greater degrees of deformity in older foals than previously reported with this or other surgical techniques.

Periosteal transection and stripping for treatment of angular limb deformities in foals: radiographic observations.

Radiographs of 23 foals (35 forelimbs) with carpal region angular limb deformities, which later were corrected by hemicircumferential transection of the periosteum and periosteal stripping, were evaluated as to geometric and morphologic abnormalities. Geometric evaluation included deviation angle and deviation pivot point. Morphologic abnormalities were categorized as: asymmetric width of the distal radial physis; asymmetric width of the distal radial epiphysis; carpal bone collapse or fracture; carpal bone hypoplasia; carpal bone displacement; and metacarpal bone displacement. Fifty-seven percent of limbs had radiographic lesions in the carpal joints and 20% had lesions in the metacarpus. Of all the limbs, 48% had carpal or metacarpal bone hypoplasia, 26% had carpal or metacarpal bone displacement, and 12% had carpal bone collapse or fragmentation. On long-term followup (5 months to 2 years), 83% of the foals were sound and had straight limbs, regardless of the deviation angle, deviation pivot point, or morphologic carpal bone changes. Sixty percent of the foals were in performance training. About 50% of these foals in performance training had carpal bone hypoplasia before correction of the deviation. It was concluded that geometric and morphologic radiographic interpretation should be performed before surgical correction of carpal angular limb deformities with hemicircumferential transection of the periosteum and periosteal stripping, but that epiphyseal, carpal bone, or metacarpal bone changes, severe deviation angle (20 to 29 degrees) or distal location of the pivot point should not discourage attempted surgical correction.

Ultrasonographic features of splenic lymphosarcoma in dogs: 12 cases (1980-1986).

The ultrasonographic appearance of the spleen and adjacent organs in 12 dogs with splenic lymphosarcoma was reviewed. Poorly marginated hypoechoic to anechoic nodules (4 mm to 3 cm in diameter) were found in all dogs. The anechoic nodules did not result in reflective shadowing or acoustic enhancement of the underlying tissues. The remainder of the splenic parenchyma appeared relatively hypoechoic when compared with the liver or renal cortices in 9 dogs. Recognition of this ultrasonographic pattern appears to be a useful diagnostic tool. Needle aspiration guided ultrasonographically will then enable histologic confirmation of lymphosarcoma.

Ultrasonographic features of splenic hemangiosarcoma in dogs: 18 cases (1980-1986).

The medical records of 18 dogs in which ultrasonography was useful in making a diagnosis of splenic hemangiosarcoma were reviewed. Splenic ultrasonography revealed masses with echo patterns that ranged from anechoic fluid to hyperechoic tissue. In 7 dogs, metastasis was detected ultrasonographically as anechoic to hypoechoic lesions in the liver.