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Biomedical subjects

R R Pool

Publications and source records attributed to R R Pool.

At least 37 records · Page 2Linked to original sources
PubMed1989

The fate of articular cartilage after transplantation of fresh and cryopreserved tissue-antigen-matched and mismatched osteochondral allografts in dogs.

The long-term success of massive osteochondral allografts depends not only on the incorporation of the transplanted articular cartilage. Osteochondral allografts are immunogenic, and, once an immune response is stimulated by exposure to donor cellular antigens, the cartilage becomes vulnerable to direct injury by cytotoxic antibodies or by lymphocytes, or to indirect injury by inflammatory mediators and enzymes induced by the immune response. To clarify the role of histocompatibility antigen-matching on the health of transplanted articular cartilage, we orthotopically implanted canine leukocyte antigen-matched and mismatched proximal osteochondral allografts of the radius, both fresh and cryopreserved, in beagles. Four groups of dogs received: (1) canine leukocyte antigen-mismatched frozen allografts, (2) canine leukocyte antigen-mismatched fresh allografts, (3) canine leukocyte antigen-matched fresh allografts, or (4) canine leukocyte antigen-matched frozen allografts. In twelve of the dogs, the contralateral leg was subjected to a sham operation, and in ten of the dogs, the proximal part of the radius was removed and replaced as an autogenous graft control. All animals were followed for eleven months after the operation and then were killed. The cartilage of the grafts was evaluated grossly, histologically, and biochemically. The biochemical analysis consisted of measurement of dry weight, content of glycosaminoglycan and hydroxyproline, and galactosamine-to-glucosamine ratios. Analyses of variance were used to study the effect of tissue antigen-matching and freezing on degradation of cartilage. During the study, no dog had grossly obvious clinical abnormalities, all host-graft interfaces healed, and no joints dislocated. The gross appearance of the cartilage was normal for both the joints that had an autogenous graft and those that were subjected to the sham operation. The cartilage of all allografts was thinned, dull, and roughened. The synovial membrane of all of the joints that had been operated on was mildly fibrotic and hyperplastic, but only that of the dogs that had an allograft was severely fibrotic and hyperplastic and demonstrated an inflammatory response. The inflammatory response was most severe in joints that had received a fresh canine leukocyte antigen-mismatched allograft. Invasive pannus was more frequent in joints that had received a fresh graft, particularly those that had received a canine leukocyte antigen-mismatched allograft, and cartilage was sometimes eroded to subchondral bone. Freezing was harmful to the cartilage. Very few cells survived the freezing procedure, and frozen grafts received s significantly worse histological scores had significantly less glycosaminoglycans and had a lower ratio of galactosamine to glucosamine than fresh grafts.

Animals↗
PubMed1988

Effect of gentamicin sulfate and sodium bicarbonate on the synovium of clinically normal equine antebrachiocarpal joints.

The effect of gentamicin sulfate, unbuffered and buffered with sodium bicarbonate, on synovial fluid and membrane of clinically normal equine joints was evaluated. Thirty-six adult horses with clinically normal antebrachiocarpal joints were allotted to 6 treatment groups of 6 horses each. One antebrachiocarpal joint in each horse was chosen for treatment. Group-1 horses were given gentamicin (3 ml; 50 mg/ml); group-2 horses were given sodium bicarbonate (3 ml; 1 mEq/ml); group-3 horses were given gentamicin (3 ml; 50 mg/ml) and sodium bicarbonate (3 ml; 1 mEq/ml); group-4 horses were not treated; and horses of groups 5 and 6 were given polyionic physiologic solution (3 and 6 ml, respectively). Synovial fluid specimens were obtained from 5 horses of each group for cytologic analysis at postinjection hours (PIH) 0, 24, 72, and 192 and for pH determination at PIH 0, 0.25, 0.5, 1, 4, 8, 24, 72, and 192. The sixth horse of each group was euthanatized at PIH 24, and the synovial membrane of the treated and contralateral (nontreated) antebrachiocarpal joints was examined macroscopically and microscopically. After intra-articular gentamicin administration, the mean synovial fluid pH was lowest (5.98) at PIH 0.25, but by PIH 8, it was not significantly different from the control value (group-5 horses). When sodium bicarbonate was combined with gentamicin before intra-articular administration, the mean synovial fluid pH was lowest (7.07) at PIH 0.25, but by PIH 1, it was not significantly different from the control value (group-6 horses).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

A technique for catheterization of the equine antebrachiocarpal joint.

A 2.5-cm long, 0.8 mm in diameter catheter was placed percutaneously into the palmarolateral pouch of the antebrachiocarpal joint in 6 clinically normal horses. The catheter was affixed in place for 72 hours. Cytologic analysis was performed on synovial fluid specimens obtained through the catheter at postcatheterization hours (PCH) 0, 24, and 72. The horses were euthanatized at PCH 72, and macroscopic and microscopic examinations were performed on the dorsal portion of the joint capsule and the palmarolateral pouch of the catheterized and contralateral (noncatheterized) joint. Clinical, synovial fluid cytologic, and synovial membrane histologic examinations were performed to assess the effect of the catheter on clinically normal equine synovial membrane. Serially obtained synovial fluid specimens were yellow and clear or hazy and had good mucinous precipitate quality at all times in all horses, except 2, in which the catheter required readjustment. Mean refractive index was slightly decreased, and the RBC count was high at PCH 24 and 72, compared with PCH 0; the highest RBC count was 12,550 cells/microliter (PCH 24). Statistically significant (P less than 0.05) increases were observed in WBC, neutrophil, and large and small mononuclear cell counts between PCH 0 and 72. These increases were modest, except the mean WBC count (51,000 cells/microliter, PCH 72) observed in 1 horse in which the catheter was dislodged, requiring reinsertion into the joint. At necropsy, subcutaneous hemorrhages were observed at the catheter insertion site in all horses. The synovial membrane of the catheterized joint was discolored (ranging from yellow-orange to salmon), compared with the contralateral synovium (noncatheterized joint).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Primary degenerative joint disease of the shoulder in a colony of beagles.

Shoulder joints of 149 Beagles over 8 years old at the time of death (mean age, 13.8 years +/- 3.21), were examined radiographically throughout their life-times for the frequency of degenerative joint disease (DJD). Clinical histories revealed no underlying cause for DJD. The shoulder joints of a subgroup of 18 dogs were examined at necropsy, and thin sections of the joints were evaluated radiographically and histologically. Serial clinical radiographic studies indicated that normal shoulder joint development during the first year of life was followed by the appearance of subchondral bone sclerosis and bony remodeling of normal joint contour, and by the formation of periarticular osteophytes and enthesiophytes. All changes were progressive with age and typical for DJD in dogs. Bilateral involvement was common. Evaluation of specimens obtained at necropsy revealed: articular cartilage change with roughening of the surface layer, degeneration and death of superficial chondrocytes, exposure of deeper layers of chondrocytes that had proliferated with fissuring of the damaged cartilage, total cartilage loss with polishing of the exposed subchondral bone, mixed patterns of subchondral bone sclerosis and osteoporosis, change in contour of the articular surfaces, and formation of periarticular osteophytes and enthesiophytes. Joint capsule thickening, synovitis, pannus formation, and synovial chondroma formation were observed. Because of the available clinical information, in addition to the typical changes of DJD, it was thought that the changes were primary. Instability appeared to play a role in the pathogenesis of the joint disease described; however, it was not clear whether the instability caused abnormal forces on healthy cartilage or whether the primary cartilage wear caused the instability.

Aging↗
PubMed1985

Correlative biomechanical and histologic study of the cranial cruciate ligament in dogs.

The mechanical properties of the cranial cruciate ligament were determined, using unilateral bone-ligament-bone preparations from 65 dogs of various ages and body sizes. Tensile loading of the cranial cruciate ligament from 1 of each pair of stifle joints demonstrated a decrease in material properties (modulus, maximum stress, strain energy) with aging. The decreases in maximum stress and strain energy with age were significantly less (P less than 0.05 and P less than 0.05, respectively) in the cranial cruciate ligament from dogs weighing less than 15 kg, compared with those weighing 15 kg or more. The cranial cruciate ligament and remaining femorotibial ligaments were collected from the opposite stifle joints and examined microscopically. By 5 years of age, the cranial cruciate ligaments of dogs weighing greater than 15 kg consistently had microscopic evidence of degenerative disease (loss of ligamentocytes, metaplasia of surviving ligamentocytes to chondrocytes, and failure to maintain collagen fibers and primary collagen bundles) which progressed in severity with age. The caudal cruciate ligaments were similarly affected, although the degenerative changes were rarely as severe as in the cranial cruciate ligament. The collateral ligaments underwent minimal degeneration. Sex differences had no bearing on degeneration. The cranial cruciate ligaments in dogs weighing less than 15 kg generally had less severe alterations than those in heavier dogs, and the onset of the degenerative process was delayed by several years. Cranial cruciate ligaments removed from dogs after ligament failure not only had degenerative disease, but also had undergone unsuccessful attempts at repair. In contrast, fibrous repair was rarely present in intact ligaments of asymptomatic dogs with degenerative disease of the cranial cruciate ligament.

Age Factors↗
PubMed1985

Effect of intra-articular gentamicin sulfate on normal equine synovial membrane.

Gentamicin sulfate (3 ml; 50 mg/ml) was administered intra-articularly into 30 normal equine radiocarpal joints after arthrocentesis. Arthrocentesis alone was performed on 10 normal radiocarpal joints. Synovial fluid evaluations and gross and microscopic examinations were performed on synovial fluid and synovial membrane of designated joints at selected daily intervals over a period of 10 days. Synovial fluid from gentamicin-injected joints had greater turbidity, higher RBC and WBC counts, and higher refractive indices than did joints not injected with gentamicin. The largest increases developed on days 1 or 2 after gentamicin injection, with mean total WBC, large mononuclear cell, small mononuclear cell, and polymorphonuclear cell counts of 23,860, 11,853, 857, and 11,150 cells/microliter, respectively. Arthrocentesis alone resulted in smaller increases in these counts. Microscopic changes seen in the synovial membrane of gentamicin-injected joints included edema, leukocytic infiltration, and loss of synovial lining cells. These inflammatory changes resolved within 7 days after gentamicin injection.

Animals↗
PubMed1984

Evidence for both prelysosomal and lysosomal intermediates in endocytic pathways.

Horseradish peroxidase (HRP), an enzyme internalized by fluid phase pinocytosis, has been used to study the process by which pinosome contents are delivered to lysosomes in Chinese hamster ovary cells. Pinosome contents were labeled by allowing cells to internalize HRP for 3-5 min. Following various chase times, cells were either processed for HRP and acid phosphatase (AcPase) cytochemistry or homogenized and fractionated in Percoll gradients. In Percoll gradients, pinosomes labeled by a 3-5 min HRP pulse behaved as a vesicle population more dense than plasma membrane and less dense than lysosomes. In pulse-chase experiments, internalized HRP was chased rapidly (3-6 min chase) to a density position intermediate between the "initial" pinocytic vesicle population and lysosomes. With longer chase periods, a progressive accumulation of HRP in more dense vesicles was observed. Correspondence between the HRP distribution and lysosomal marker distribution was reached after a approximately 1-h chase. By electron microscope cytochemistry of intact cells, the predominant class of HRP-positive vesicles after pulse uptakes or a 3-min chase period was characterized by a peripheral rim of reaction product and was AcPase negative. After 10-120-min chase periods, the predominant class of HRP-positive vesicles was characterized by luminal deposits and HRP activity was frequently observed in multivesicular bodies. HRP-positive vesicles after a 10- or 30-min chase were AcPase-positive. No HRP activity was detected in Golgi apparatus. Together these observations indicate that progressive processing of vesicular components of the vacuolar apparatus occurs at both a prelysosomal and lysosomal stage.

Animals↗
PubMed1984

Squamous cell carcinoma in the jaws of beagles exposed to 90Sr throughout life: beta flux measurements at the mandible and tooth surfaces and a hypothesis for tumorigenesis.

We present the first detailed dose-response measurements for 90Sr-induced soft tissue tumors other than hemopoietic dyscrasias in chronically exposed beagles. Twenty-four of 387 dogs exposed to 90Sr beginning in utero and by continuous ingestion to 540 days of age developed squamous cell carcinoma of the jaw during their lifetime. Eleven of the 24 tumors were observed in dogs ingesting 12 microCi/day and receiving cumulative average doses of 6500-12,000 rad. None of these tumors was observed in dogs ingesting less than 1.25 microCi/day and receiving cumulative skeletal average doses of 2100-3900 rad, but four were observed at this level. The teeth of these animals acquired a 90Sr burden that is not removed by skeletal remodeling. Measurements of the radiation dose to soft tissue adjacent to the mandible and teeth of dogs chronically fed 90Sr indicated the first 10 micron of soft tissue adjacent to teeth received a radiation dose initially about the same as the average skeletal doses. By 2000-3000 days, these tissues received about two to three times that calculated for the average skeletal dose, or about four to six times the mean marrow dose. We suggest that these tumors arise from epithelial rests, which are embryonic tissue trapped in the periodontal membrane between teeth and bone.

Administration, Oral↗
PubMed1983

Experimental and clinical investigations of the use of carbon fiber sutures in equine tendon repair.

Braided carbon fiber sutures were used to repair surgically transected or lacerated digital flexor tendons of 20 mature horses (10 experimental and 10 clinical cases). In addition, 4 experimental horses had tenectomies that were not surgically repaired; these served as controls for the horses with carbon-implanted tendons. Six of the 10 clinically affected horses were returned to their intended use; 2 were euthanatized because of complications and 2 were still recuperating. The experimental horses were euthanatized at 12 days and 1, 2, 4, 8, and 12 months. Tendon scars were structurally and functionally similar in all of these horses. The main histologic difference between the controls and principals was the more extensive remodeling in the latter group at 8 months.

Animals↗
PubMed1983

Characterization of pinocytic vesicles from CHO cells: resolution of pinosomes from lysosomes by analytical centrifugation.

Pinocytic vesicles (pinosomes) and lysosomes from suspension cultured, Chinese hamster ovary (CHO-S) cells have been resolved as two non-overlapping organelle populations by analytical centrifugation in Percoll gradients. Pinosomes were labeled with either horseradish peroxidase (HRP), a fluid phase content marker, or by radioiodination by pinocytosed lactoperoxidase (LPO). CHO-S cell lysosomes followed by three different marker enzymes and electron microscopy behaved as a single, dense organelle population. Pinosomes were partially resolved from plasma membrane, a less dense organelle population.

Animals↗
PubMed1983

Comparative pathogenesis of radium-induced intracortical bone lesions in humans and beagles.

Morphologic changes resulting from the effects of chronic radionuclide toxicity (226Ra) in the skeletons of workers in the radioluminescent dial painting industry with preterminal body burdens ranging from about 1.5 to 0.042 muCi were compared with the pathologic alterations in the skeletons of a group of 38 beagle dogs injected with 1.12 muCi/kg. Similarities observed in the skeletal responses of the two species were the presence of (1) dead bone tissue with delayed resolution, (2) a chronic disturbance in the remodeling mechanism of bone tissue, and (3) radiation-induced bone sarcomas. A detailed analysis of sequential changes in radiographic lesions arising in the beagle skeletons, complemented by histopathologic evaluation at the time of limb amputation or at necropsy, has enabled us to examined the disturbance in the bone remodeling process. The perturbation of critical importance in the generation of primary bone tumors appears to lie in the bone tissue formation and deposition phase of the bone remodeling process and gives rise to a spectrum of histologic patterns which we have termed "radiation osteodystrophy." While some of the newly generated patterns demonstrate indolent behavior with fibrous tissue replacement and bone marrow refill, other sites of bone resorption are replaced by a unique fibro-osseous tissue response resembling fibrous dysplasia or osteoblastoma. Some of these proliferative lesions may undergo progressive malignant degeneration. While the more indolent part of the spectrum was also seen in human skeletal tissues, only premalignant and early sarcomatous stages were seen in canine tissues.

Animals↗
PubMed1983

Comparison of radiological changes in humans and beagles with skeletal deposits of radium.

At the Laboratory for Energy-related Health Research at the University of California, Davis, semimonthly injections of 226Ra were given to a group of beagle dogs, and periodic skeletal radiography followed, as well as histological studies of the bones. At the Center for Human Radiobiology (Argonne National Laboratory, Massachusetts Institute of Technology, New Jersey Radium Research Project) measurements were made of radium body content in 2259 occupationally or iatrogenically exposed persons. Of these, 1768 had skeletal radiography (one or more times). In humans, the radiographic changes were, in decreasing order of frequency, osteolytic cortical and cancellous bone destruction, bone sclerosis, pathological fracture, and avascular necrosis of bone. In beagles, osteolytic destruction and pathological fractures were common, avascular necrosis was not observed, but there was frequently cortical thickening and new-bone formation in cancellous bone. In both population groups, there was a high incidence of bone sarcoma. In the beagles, one high-dosage group numbering 38 dogs had 49 malignant bone tumors. Among the 2259 measured persons, there were 60 who had bone sarcoma, and 29 who had cancer of the mastoids or paranasal sinuses. No significant skeletal effects have been diagnosed radiologically in persons with systemic intakes of 226Ra or 228Ra below about 10 mu Ci or with skeletal doses below about 100 rad. In humans, the lowest skeletal dose at which a bone sarcoma has been diagnosed is 890 rad, and the lowest intake associated with a bone sarcoma is 96 mu Ci 226Ra or about 1.7 mu Ci per kg body weight.

Animals↗
PubMed1983

Effects of tendon transfer on the canine scapulohumeral joint.

Surgical techniques for correcting medial or lateral instability of the scapulohumeral joint in conditioned research dogs were evaluated. Lateral instability was created by severing the lateral joint capsule and the tendon of insertion of the infraspinatus muscle. In 4 dogs, the tendon of origin of the biceps brachii muscle was then transferred to a position lateral to the greater tubercle in an effort to improve lateral stability. In 3 control dogs, lateral instability was induced, but attempt was not made to stabilize the joint. Medial instability was created by severing the tendon of insertion of the subscapularis muscle and the medial joint capsule. In 3 dogs, the tendon of origin of the biceps brachii muscle was transferred to a position under the lesser tubercle. In 2 dogs, a portion of the tendon of insertion of the supraspinatus muscle was transferred to a medial location. In 3 control dogs, attempt was not made to stabilize the joint. The control dogs (n = 6) demonstrated mild-to-moderate weight-bearing lameness for 7 to 14 days after surgical induction of joint instability and thereafter had normal limb usage. Dogs having had tendon transfer procedures recovered normal limb usage in 4 to 6 weeks and thereafter behaved normally. At necropsy, all joints appeared stable, and the surgical repairs were intact. A variety of joint surface abnormalities consistent with degenerative joint disease was observed, but no consistent pattern was assignable to any given surgical manipulation.

Animals↗