Neoplasms in young dogs after perinatal irradiation.

For a study of the life-time effects of irradiation during development, 1,680 beagles were given single, whole-body exposures to 60Co gamma-radiation at one of three prenatal (preimplantation, embryonic, and fetal) or at one of three postnatal (neonatal, juvenile, and young adult) ages. Mean doses were 0, 0.16, or 0.83 Gy. For comparison with data on childhood cancer after prenatal irradiation, examination was made of tumors occurring in young dogs in this life-span experiment. Up to 4 years of age, 18 dogs had neoplasms diagnosed, 2 of these being in controls. Four dogs that were irradiated in the perinatal (late fetal or neonatal) period died of cancers prior to 2 years of age. This risk was of significant increase compared to the risks for other experimental groups and for the canine population in general. Overall, 71% (5 of 7) of all cancers and 56% (10 of 18) of all benign and malignant neoplasms seen in the first 4 years of life occurred in 29% (480 of 1,680) of the dogs irradiated in the perinatal period. These data suggest an increased risk for neoplasia after perinatal irradiation in dogs.

Enhanced tumor uptake of macromolecules induced by a novel vasoactive interleukin 2 immunoconjugate.

Low uptake of monoclonal antibodies (MAbs) in cancer lesions is a significant problem in cancer therapy. Recent studies have shown that antibody uptake in tumor is controlled in large part by the tumor blood flow and the vascular permeability of the tumor endothelium. We have hypothesized that these physiological properties of tumor vessels may be altered by pretreatment with vasoactive drugs or peptides linked to tumor-specific MAbs. To test this hypothesis, two MAbs, Lym-1 directed against human malignant lymphomas and B72.3 reactive with the TAG-72 antigen expressed in solid tumors, were chemically conjugated with human recombinant interleukin 2 (IL-2). IL-2 has been used in humans to activate lymphokine-activated killer cells for the treatment of cancer but is also known to produce a generalized vascular permeability by an unknown mechanism when used systemically. Chemical conjugation of IL-2 to MAbs appears to destroy its cytokine function as shown by T-cell proliferation studies in vitro. Despite this finding, MAb/IL-2 immunoconjugates retain their ability to produce an enhanced vascular permeability when injected i.v. into nude mice bearing relevant tumor models only. Biodistribution studies using 125I-labeled tracer Lym-1 have demonstrated that the Lym-1/IL-2 immunoconjugate can increase antibody uptake in tumor by a factor of 4 in a time (2.5-h pretreatment)- and dose (30 micrograms/mouse)-dependent manner. In contrast, treatment of mice with free IL-2 and antibody showed this effect in all organs of the mouse including the tumor. Bidirectional crossover imaging studies in individual tumor-bearing nude mice showed improved uptake and decreased blood pool when the MAb/IL-2 immunoconjugates were used compared to controls. Finally, tumor blood flow and vascular permeability studies demonstrate that the physiological effect of the MAb/IL-2 is due to a reversible and specific vascular leakage at the tumor site. These studies indicate that pretreatment with this novel immunoconjugate may enhance the diagnostic and therapeutic potential of MAbs, drugs, and other macromolecules for the treatment of cancer.

Effects of irradiation on the nonlymphoid thymus in vitro.

Thymic explant cultures were used to study the radiosensitivity of nonlymphoid thymic components in dogs. Thymic fragments from fetal (50 days gestation), newborn, and juvenile (70 days old) dogs were irradiated in vitro at 0, 0.5, 1, 2, or 4 Gy prior to culture. Colonies were classified as epithelial, spindle, or mixed cell type, and colony numbers were counted and diameters measured. Radiation caused a significant dose-related decrease in the number of spindle cell colonies from all ages. There was a corresponding, but smaller, dose-related increase in the number of epithelial colonies. The diameter of spindle cell colonies also decreased with dose, and this was accompanied by a reduction in cell density. While epithelial colony diameters did not change consistently with dose, there was an overall reduction in cell density in these colonies. This was more severe in the fetal than in the juvenile cultures. These results indicate that the putative mesenchymal (spindle cell) components of the thymus are significantly more radiosensitive than the epithelium at all ages and that fetal epithelium is more sensitive than epithelium from postnatal animals. This suggests that radiation-induced thymic epithelial defects reported after prenatal irradiation could be due to a combination of direct epithelial injury and defective inductive interaction between epithelium and the more radiosensitive mesenchyme.

Alterations in immune responses in prenatally irradiated dogs.

Immunologic responses were studied in beagle dogs following prenatal (35 days gestation) irradiation to evaluate the effects of ionizing radiation on the developing immune system. Each dog received 1.5 Gy 60Co gamma irradiation or sham irradiation. Prenatally irradiated dogs exhibited a significant reduction in primary humoral antibody responses to inoculated sheep red blood cells, a T-dependent antigen, and a concurrent decrease in T-helper lymphocyte subpopulations in the peripheral blood at 3 to 4 months of age. Similarly, irradiated fetuses have been shown to have defects in epitheliostromal development of the thymus. It is suggested that the postnatal immunologic deficits may relate to the prenatal thymic injury.

Prenatal and neonatal irradiation in dogs: hematologic and hematopoietic responses.

Hematologic and hematopoietic responses were evaluated in beagle dogs following a single prenatal (35 days gestation) or neonatal (10 days postpartum) exposure to 1.5 Gy 60Co gamma radiation. Hematopoiesis was studied by the in vitro culture of bone marrow granulocyte-macrophage progenitors (CFU-GM). Prenatally irradiated dogs exhibited a progressive, significant reduction in CFU-GM which was accompanied by decreases in peripheral blood leukocytes up to 24 weeks of age. Dogs which were neonatally irradiated also demonstrated a significant reduction in CFU-GM which was accompanied by significant alterations in peripheral white and red blood cell parameters. This was transient, however, and these dogs showed partial recovery of CFU-GM and hematologic parameter by 24 weeks of age. The persistent CFU-GM deficit in prenatally irradiated dogs suggests a relatively greater sensitivity of fetal marrow as compared to neonatal bone marrow for long-term damage by ionizing radiation.

Treatment of displaced segmental radial-head fractures. Long-term follow-up.

We did a retrospective study of forty segmental fractures of the radial head in thirty-nine patients. Good results were achieved in twenty of thirty-four fractures with non-operative treatment. In six patients the radial head was excised totally and in only one was a good result achieved. The average follow-up was 10.0 years. Only rarely was there deterioration of the short-term results. The prognosis was not affected by the extent of the depression, the size of the fragment, or the degree of comminution. We concluded that the only indication for operation in this type of fracture is a loose fragment in the joint.

Effects of corticosterone on reproduction in male Sprague-Dawley rats.

Corticosterone, the predominant circulating adrenal corticosteroid in rodents, was investigated for its effects on reproduction in male Sprague-Dawley rats. Male rats (in groups of 50, 25, and 50) were administered corticosterone at doses of 0, 10, and 25 mg/kg/d, respectively, by subcutaneous injection once daily for 6 weeks; the highest dose was decreased to 20 mg/kg/d after 15 d. During the last 2 weeks of the 6-week treatment period, 25 males per group were paired with untreated females. The remaining 25 males from the 0 and 25/20 mg/kg/d groups were allowed a 6-week recovery period and, during the last 2 weeks of this period, these males were also paired with untreated females. At the end of the treatment period, the males had markedly elevated plasma corticosterone concentrations and decreased weight gain. They also produced fewer copulatory plugs than controls, which may have been secondary to observed adverse effects on the accessory sex organs (decreased weights and microscopic changes in prostate and seminal vesicles). However, no adverse effects on sperm motility, sperm count, or microscopic features of the testes were observed. Serum testosterone concentration of the high-dose males was elevated, but luteinizing hormone was unaffected. The numbers of embryonic implantation sites and live fetuses in females mated to these males were reduced. All of these effects except decreased prostate weights were reversible upon cessation of corticosterone administration. Thus, exogenous administration of corticosterone to male rats produced reversible effects on implant count and litter size of female rats mated to these males. These effects on male rat reproduction may have been secondary to reduced accessory sex organ function, which resulted in diminished secretions and fewer copulatory plugs.

Immunologic and biochemical analysis of TNT-1 and TNT-2 monoclonal antibody binding to histones.

Two novel murine monoclonal antibodies that bind to intracellular antigens, designated TNT-1 and TNT-2, have been generated by immunizing mice with nuclear extracts from human lymphoma cells. The monoclonal antibodies were initially identified by indirect immunofluorescence on lymphoma cell lines and subsequently were found to stain the nucleus of all cell types from several species including plants by indirect immunofluorescence techniques. Immunoblot analysis demonstrated that TNT-1 bound to a protein of 22 kD and TNT-2 bound to two proteins of 15 and 22 kD, consistent with the known molecular weight of histones. To characterize their immunoreactivity, competition radioimmunoassays were performed using purified histone fractions H1, H2a, H2b and H3. By these assays, TNT-1 was found to bind to histone fraction H1 and TNT-2 to an epitope common to histone fractions H1 and H3. Histones are found in abundance in the nucleus of the cell and are known to play a major role in chromosome structure and gene expression. Upon cell death, histones remain tightly bound to DNA and consequently provide an abundant intracellular antigen that can be exploited in targeting necrotic cells, such as those found in tumors.

Interreader agreement on comprehensive essay examinations.

Examination of faculty interreader reliability on essay-type comprehensive examinations revealed an overall agreement rate of 85.6%. No significant differences in agreement were found between departments. Examination of reader characteristics for those exams with 100 points variation between readers revealed no consistent differences. The findings support the use of one format with a structured scoring protocol for evaluating diverse clinical specialties.

The use of electrosurgery for arthroscopic subcutaneous lateral release.

49 patients underwent subcutaneous lateral retinacular release for pa tell of emo ral malalignment syndromes by a new technique utilizing the arthroscope and electrocautery. In this technique, the tight lateral patellofemoral ligament and lateral retinaculum are transected with the electrocautery under direct arthroscopic visualization. It is possible to directly observe the progress and completeness of the release, and to cauterize any bleeding vessels sequentially as they are transected. The procedure is simple, quick, and has a low 3.8% rate of complication. In the postoperative period pain is minimal, requiring only non-narcotic medication. Patient hospital stay is reduced, with dismissal usually one day after surgery. Knee motion as well as quadriceps control are rapidly recovered. One week after surgery 90% of patients gained 90° or more of flexion, and the remaining patients achieved this by the second week after surgery.

Diagnostic and surgical arthroscopy.

Arthroscopy has developed dramatically over the last 10 years. Surgeons now have the ability to perform many procedures arthroscopically in almost any joint that previously required arthrotomy. This has resulted in notable benefits in decreased morbidity, earlier return to full activity, and decreased cost. Considerable experimental work is being done to apply arthroscopic procedures to joints other than the knee and shoulder in order to develop new procedures to successfully treat disorders in these areas.

Operative arthroscopy into the next century.

Until 10 years ago, operative arthroscopy was largely restricted to the knee. However, shoulder arthroscopy can now stabilize instability and repair rotator cuff tears. Operative procedures are seven being extended into the wrist and ankle.

A prospective study comparing the accuracy of the clinical diagnosis of meniscus tear with magnetic resonance imaging and its effect on clinical outcome.

A prospective, single-blind study of 57 consecutive knees with an initial clinical diagnosis of a torn meniscus was completed to test the hypothesis that a routine preoperative magnetic resonance imaging (MRI) scan could improve accuracy over clinical diagnosis alone. The overall accuracy for the clinical diagnosis of meniscal tear was 80.7% and the corresponding accuracy for MRI was 73.7%. Surgical pathology was found in all knees at arthroscopy. Relying blindly on MRI to determine surgical intervention would have resulted in inappropriate treatment in 35.1% of the knees. A surgeon can safely rely on the clinical diagnosis of meniscal tear alone and will find surgical pathology in almost all cases. Relying on MRI alone without using clinical judgment may lead to inappropriate treatment in a high percentage of cases. Clinical examination alone is at least as accurate as MRI. MRI did not prevent "unnecessary surgery" in any case. MRI should be reserved for confusing or special cases.

Radiation-induced quantitative alterations in prenatal thymic development in the beagle dog.

Quantitative morphology of the canine fetal thymus was studied to evaluate the age-dependent radiosensitivity of the developing immune system. Pregnant beagle dams received abdominal 60Co gamma exposures (200 R) or were sham irradiated at one of three ages in gestation, 30, 40, or 45 days. The mean calculated dose to each fetus was 1.5 Gray. One-half of the fetuses in each litter were harvested by hysterotomy at 5 days and one-half at 10 days post-irradiation (PI). The volumes of the thymic lobules and lobular cortices were significantly reduced at 5 and 10 days PI when compared with age-matched controls. Thymic cortical volumes in irradiated fetuses were reduced between 13 and 29% from control volumes by 5 days PI and 8 and 13% by 10 day PI. Thymic medullary volumes in irradiated fetuses were reduced 18 to 23% by 5 days PI and 27 to 54% by 10 days PI. The reductions in medullary volumes in fetuses irradiated at 35, 40, and 45 days of gestation and evaluated at 10 days PI were 54, 38, and 27%, respectively. Although injury to both thymic cortices and medullas was greater following exposures earlier in gestation, damage to medullas was relatively more severe than in cortices following exposure at any one age. The degree of reduction of medullary volume reflects thymic epithelial injury and is surprising since thymic epithelium is considered to be radioresistant in the adult. Such injury may have serious consequences postnatally as normal differentiation of T cell subpopulations is dependent upon the integrity of the thymic microenvironment. Damage to the thymic microenvironment could result in defects in immunologic regulation and in immune deficiencies.

Effect of seven new vasoactive immunoconjugates on the enhancement of monoclonal antibody uptake in tumors.

BACKGROUND: To enhance monoclonal antibody uptake in tumors, seven novel vasoactive immunoconjugates were developed that selectively alter the vascular permeability and/or blood volume of tumors in vivo. These immunoconjugates, composed of IL-1 beta, IL-2, TNF-alpha, physalaemin, leukotriene B4, histamine, and bradykinin chemically linked to TNT-1, a murine monoclonal antibody that binds necrotic regions in tumors, have been tested for their effects on antibody uptake in vivo. METHODS: Groups of four mice, each bearing the ME-180 human cervical carcinoma, were pretreated either 3 or 24 hours before the administration of I-125 labeled TNT-1 F(ab')2 fragment. Three-day biodistribution studies then were performed to determine the amount of radiolabeled antibody in the tumors and normal organs of the mice. In addition, mechanism of action studies were performed to determine if the vasoactive immunoconjugate affected the vascular permeability or blood volume of the tumor vessels. RESULTS: TNT-1/IL-2 gave the highest percent injected dose/g in tumor (4.80), compared with TNT-1/TNF (4.00), TNT-1/IL-1 (3.83), TNT-1/leukotriene-B4 (2.84), TNT-1/histamine (2.80), TNT-1/physalaemin (2.19), TNT-1/bradykinin (1.57), or TNT-1 alone (1.28). All of these immunoconjugates showed specific enhancement of monoclonal antibody uptake in tumor with no changes seen in normal tissues. Quantitative studies that demonstrated the mechanism of action of these immunoconjugates showed that TNT-1/IL-2 and TNT-1/histamine produced a marked change in the vasopermeability of tumor vessels but had no effect on tumor blood volume. In contrast, TNT-1/IL-1 and TNT-1/TNF produced a combination of effects, and TNT-1/leukotriene B4, TNT-1/bradykinin, and TNT-1/physalaemin affected only tumor blood volume. CONCLUSIONS: These studies indicate that pretreatment with vasoactive immunoconjugates may improve monoclonal antibody uptake in tumors significantly and thereby increase the therapeutic index of monoclonal antibody-directed immunotherapy.

The effect of technique on histology of arthroscopic partial meniscectomy with electrosurgery.

Fifty-one patients had arthroscopic partial meniscectomies with electrosurgery between 1982 and 1985. Two patients who had undergone prior meniscectomies with electrosurgery had biopsies of the old excision site at repeat arthroscopy, necessitated by new injuries. Three different combinations of electrocautery tips and either a standard electrocautery generator or a new electrocautery generator specifically designed for arthroscopic electrosurgery were used in different combinations. Depth of damage as defined by the Trichrome stain was measured by a micrometer. A rating summary of the quality of resection technique was also performed. Overall, the newly developed electrocautery generator and the newly developed electrocautery tips were not beneficial in reducing the depth of damage. The average depth of damage was .29 mm. Forty-seven percent of patients showed no histologic evidence of damage from the electrosurgical resection. The two individuals with repeat biopsies showed normal histology. Arthroscopic partial meniscectomy with electrosurgery causes a very thin layer of tissue damage. This appears to resolve with time. Recently developed instruments specifically designed for arthroscopic electrosurgery do not appear to decrease the depth of damage.

The treatment of idiopathic osteonecrosis of the medial femoral condyle with arthroscopic debridement.

Five patients with idiopathic osteonecrosis underwent arthroscopic debridement with instruments designed for arthroscopic abrasion arthroplasty. Each lesion was large enough to require total knee or tibial osteotomy using criteria previously published by other authors. Using the Hospital for Special Surgery Rating System, four of five patients were rated good postoperatively (average rating: preop 52 points and postop 82 points). Biopsies of two patients at repeat arthroscopy showed that fibrocartilage fills in the defects created by the debridement. Average follow-up was 31 months.

The growth of nonlymphoid thymic components in vitro: age-related differences during development.

An explant culture procedure has been developed that makes it possible to measure the relative growth capacity of the epithelial and mesenchymal cells of the canine thymus gland. Standardized growth conditions were obtained by size-grading thymic fragments and counting to allow uniform fragment density during culture. After 6 d in culture, outgrowth from the fragments formed colonies that could be classified into epithelial, mixed, or spindle cell type. Uniform fragment size and number in each flask allowed calculation of the total plating efficiency, relative distribution of colony types, and mean colony diameters for thymic fragments collected from fetuses (50 d of gestation), neonates (0 d postpartum), and juveniles (70 d postpartum). Data show age-related changes in the proliferative capacity of the cells in all three colony types. The most significant difference was seen in the epithelium, which showed a 30% reduction in mean colony diameter over the 2 wk between fetal and neonatal ages and a 23% reduction over the postnatal period of 70 d. Significant reductions were seen in the other colony types as well. Because the severity of the effect of many injurious agents is proportional to the rate of growth of the target cells, these data suggest that the thymus gland of the fetus may be more sensitive to physical or chemical injury than is the neonate or adult.

Chronic effects of the novel glucocorticosteroid RPR 106541 administered to beagle dogs by inhalation.

The preclinical safety of RPR 106541, a novel 17-thiosteroid, was evaluated in young adult and mature dogs by inhalation exposure for 26 weeks and 52 weeks, respectively. A dry powder formulation of RPR 106541 in lactose was administered to young adult dogs (approximately 6 months of age at initiation) at doses of 0 (air and placebo controls), 10, 100, or 1,000 microg/kg/d for 26 weeks. A solution-based aerosol formulation was administered to mature dogs (approximately 10 months at initiation) from a pressurized metered dose inhaler at 0 (air and placebo controls), 10, 50, and 150 microg/kg/d for 52 weeks. Clinical evidence of glucocorticosteroid-induced immunosuppression was observed by weeks 20-26 following relatively high dose exposures (100 microg/kg/d and 1,000 microg/kg/d) in young dogs receiving the dry powder formulation for 26 weeks. Classic glucocorticosteroid effects were observed, including adrenocortical atrophy, reduced bone mass with retention of epiphyseal growth plates in long bones, prominence of stromal adipose tissue in bone marrow, and atrophy of lymphoid tissues. Inhalation administration of RPR 106541 to sexually mature dogs facilitated more definitive characterization of endocrine affects of RPR 106541 as compared with administration in younger, sexually immature animals. Significant effects in female reproductive organs included absence of corpora lutea in association with atresia of vesicular follicles within the ovaries, endometrial hyperplasia, and lobular development of mammary tissue. Discordant development of mammary tissue, accumulation of secretory material within hyperplastic endometrial glands, and hypertrophy of uterine lining epithelium in absence of ovulation were consistent with a secondary progestin effect by a potent glucocorticosteroid.

Laryngeal contact ulcers in feedlot cattle.

Of 30,444 larynges from fattened cattle at three companies, 3,985 (13.1%) had contact ulcers or ulcer scars in the mucous membranes over the vocal processes and medial angles of the arytenoid cartilages. The incidence was higher in cattle fed during fall than in cattle fed during other seasons. We hypothesize: 1. that some feedlot cattle develop acute mucositis from mixed infections with species of Pasteurella, Haemophilus, Mycoplasma, and viruses in the nose, pharynx, and larynx; 2. that reflex coughing and swallowing accelerate the rate of larynx closure; and 3. that the closures erode the swollen membrane over the vocal processes and medial angles of the arytenoid cartilages and thus produce primary contact ulcers.