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Biomedical subjects

R D Howard

Publications and source records attributed to R D Howard.

At least 19 recordsLinked to original sources
PubMed1995

Arthroscopic surgery for subchondral cystic lesions of the medial femoral condyle in horses: 41 cases (1988-1991).

Clinical signs, radiographic and arthroscopic findings, and outcome for 41 horses with subchondral cystic lesions of the medial femoral condyle treated by arthroscopic surgery were reviewed. There were 17. Quarter Horses, 15 Arabians, 8 Thoroughbreds, and 1 Holsteiner, with 28 (68%) of the horses being 1 to 3 years old. For all horses, the owners' complaint was mild to moderate hind limb lameness or an altered gait. Bilateral radiographic abnormalities of the medial femoral condyle were detected in 27 horses. Nineteen of the 27 horses had lesions identified bilaterally at arthroscopic surgery. In addition to the subchondral cystic lesion, 13 joints in 11 horses had an osteochondritis dissecans lesion on the articular surface of the medial femoral condyle that extended from the opening of the subchondral cystic lesion. Surgical debridement performed via arthroscopy was the only treatment for 37 lesions of 23 horses. Debridement followed by drilling of the defect bed was performed in 23 lesions of 18 horses. Complete follow-up information was obtained for 39 horses; 22 (56%) had a successful result and 17 (44%) had an unsuccessful result. In a separate analysis excluding horses with unsuccessful results because of factors not directly attributable to the subchondral cystic lesion of the medial femoral condyle, 23 of 31 (74%) horses had a successful result and 8 of 31 (26%) horses had an unsuccessful result.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Long-term fate and effects of exercise on sternal cartilage autografts used for repair of large osteochondral defects in horses.

Bilateral osteochondral defects (10 mm2 x 3 mm deep) were created on the distal articular surface of the radial carpal bone of ten, 2- to 3-year-old horses. One defect of each horse was repaired, using a sternal cartilage autograft (treated), and the other was left untreated (control). The horses were exercised on a high-speed treadmill at incrementally increased speed and duration over the course of 12 months. Horses were evaluated arthroscopically at 6 to 7 weeks, and clinical examinations were conducted weekly at exercise. Twelve months after surgery, carpuses of each horse were radiographed and clinically examined prior to euthanasia. A gross pathologic evaluation of each joint was conducted, and samples were collected for histologic, histochemical, histomorphometric, and biochemical evaluation. Radiographically, the grafted joints had more extensive evidence of arthropathy, and clinically, 8 of the 10 horses were more lame in the grafted limb. On the basis of histomorphometry, the repair tissue of the grafted defects contained a greater median percentage of hyaline cartilage (45%) than that of control defects (4.5%), and the control defects contained a greater percentage of fibrocartilage (82%) than did grafted defects (28.5%). A greater median percentage of repair tissue stained with safranin-O in the grafted defects (24.5%) than in the control defects (3.5%). On gross pathologic and histologic evaluation, repair tissue of the control defects had better continuity and was more firmly attached to the subchondral bone than was repair tissue of the grafted defects. Repair tissue of the grafted defects had extensive fissure and flap formation. Histologically, subchondral bone reactivity and fibroplasia was extensive in grafted joints. Repair tissue of grafted defects had a greater percentage of type II collagen (mean +/- SEM, 83.5 +/- 2.95%) than did controls (mean, 79.4 +/- 3.87%) that was not statistically significant. Hexosamine content was significantly higher (P < 0.05) in repair tissue of the grafted defect (mean, 28.9 +/- 3.00 mg/g of dry weight) vs control (mean, 20.6 +/- 1.85 mg/g of dry weight). On the basis of this experimental model, sternal cartilage autografts cannot be recommended at this time for repair of osteochondral defects in athletic horses.

Animals↗
PubMed1993

Evaluation of occlusive dressings for management of full-thickness excisional wounds on the distal portion of the limbs of horses.

Two 2.5-cm2 full-thickness skin wounds were created surgically over the lateral aspect of the cannon bone of each limb of 6 horses (n = 48 wounds). Dressings evaluated were a nonadherent gauze pad (group 1); a synthetic semiocclusive dressing, (group 2); equine amnion (group 3); and a synthetic fully occlusive dressing (group 4). Wounds were assessed subjectively at each dressing change, and total wound area, area of granulation tissue, and area of epithelium in each wound were determined by computerized digital analysis of photographs of the wounds. Complete healing time (wound covered by epithelium) also was determined for each wound. Statistical comparisons were made, using Kruskal-Wallis analysis and a Mann-Whitney U test. Median time to complete healing was: group 1, 53 days; group 2, 71 days; group 3, 63 days; and group 4, 113 days. Time to complete healing was significantly longer for wounds of group-4 horses than all other groups, and wounds of group-1 horses healed faster than did those of group-2 horses (P < 0.05). Wounds in group-4 horses required significantly (P < or = 0.05) more excisions of granulation tissue (median, 11.5 times) than did those in group-1 (median, 3.5), group-2 (median, 5.5) or group-3 (median, 2.5) horses. Epithelial tissue was detected later in wounds of group-4 horses (median, 27 days) than in wounds of horses in groups 1, 2 or 3 (median, 17 days); however, this difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Premarital contraceptive use: a discriminant analysis approach.

The ability of seven independent variables to predict accurately, from a sample of unmarried, sexually active students, which ones use reliable contraceptives and which ones use unreliable contraceptives, was investigated. Using discriminant analysis, the seven independent variables were age individuals started engaging in coitus, frequency of coitus, frequency of dating, length of time sex partners knew each other, number of sex partners, having anticipated coitus to occur, and the number of close friends who were thought to use birth control. The results indicated that these variables were accurate in predicting which students were users of contraceptives, with more than 80% of males and females being correctly classified. The number of close friends thought to use contraceptives was the most influential variable for both sexes, followed by length of time the partners knew each other.

Adult↗
PubMed1984

Dilaceration.

Explore the source record for details and available documents.

Humans↗
PubMed1978

Maxillary anterior displacement and impaction in the mixed dentition.

Attention has been given to problems of eruption in the maxillary anterior region. It is a region where a variety of anomalies occur. Since the maxillary anterior region influences appearance so greatly, early detection of difficulties and careful planning and treatment can be extremely beneficial to patients.

Child↗