Radiation effects on the lung: clinical features, pathology, and imaging findings.
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Diagnosis, Differential↗
Biomedical subjects
S D Davis
Publications and source records attributed to S D Davis.
Radiology of congenital abnormalities of the chest.
Radiologic imaging plays a critical role in the management of congenital abnormalities affecting the tracheobronchial tree, lung parenchyma, pulmonary vessels, and the mediastinum. Although procedures such as bronchoscopy, bronchography, and angiography may at times still be required, diagnosis is now usually established noninvasively using ultrasound, CT, MR imaging, or radionuclide imaging techniques. Earlier diagnosis, even in the antenatal period, is possible, thus allowing more prompt and effective treatment. Patients with congenital abnormalities that were previously fatal in infancy and childhood are surviving into adulthood. Clinicians and radiologists alike must now be able to recognize congenital disorders in patients who may have minimal or absent symptoms.
Bronchi↗
Effects of steroid administration on pituitary luteinizing hormone and follicle-stimulating hormone in ovariectomized pony mares in the early spring: pituitary responsiveness to gonadotropin-releasing hormone and pituitary gonadotropin content.
These experiments tested the hypothesis that administration of steroid hormones to ovariectomized (OVX) mares during the vernal transition to the breeding season would influence LH and FSH secretion. Circulating gonadotropin concentrations, response to exogenous GnRH, and pituitary gonadotropin content were monitored. Experiments 1 and 2 were conducted, beginning 10 March, and 3 February, respectively, utilizing a total of 30 long-term OVX pony mares. In experiment 1, mares were administered vehicle (n = 5) or estradiol-17 beta (E2, n = 5, 5 mg/3 ml sesame oil), twice daily for 16 days. Blood samples were collected daily for assessment of circulating LH and FSH concentrations. On Day 10 of treatment, 400 micrograms GnRH were administered to all mares. LH increased significantly over days of treatment in the estradiol-treated group, but pituitary response to GnRH tended to be less than in control mares. Circulating FSH tended to decline over days of treatment in estradiol-treated mares, and the pituitary response to GnRH was significantly reduced. Pituitary LH, but not FSH, was increased on Day 16 of treatment with estradiol. In experiment 2, 20 OVX mares received, twice daily, vehicle (n = 5), E2, n = 5; 5 mg), progesterone (P4, n = 5; 100 mg), or progesterone plus estradiol (P4/E2, n = 5; 100 + 5 mg). Treatment continued for 14 days. GnRH (100 micrograms) challenges were administered on Days 6 and 13 of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Anestrus↗
CT evaluation for pulmonary metastases in patients with extrathoracic malignancy.
Computed tomography (CT) is clearly more sensitive than chest radiography or conventional linear tomography in the detection of pulmonary metastases. Routine chest CT scans may reveal peripheral nodules as small as 2-3 mm, and high-resolution CT may demonstrate lymphangitic carcinomatosis. Specificity remains a problem, but attention to clinical factors, such as the type of extrathoracic malignancy (ETM), epidemiology, patient age, and prior treatment, should be of assistance. CT is useful in the evaluation of an apparent solitary pulmonary nodule or an equivocal radiographic finding. For single or multiple nodules, CT is essential for planning invasive procedures such as biopsy or surgical resection. Routine CT scanning to screen for occult metastases is indicated only for patients with ETMs that have a high propensity for metastasizing to the lungs and for which detection of pulmonary metastases would influence therapy--bone and soft-tissue sarcomas, most pediatric tumors, choriocarcinoma, nonseminomatous testicular carcinoma, and possibly advanced melanoma. Future large prospective studies evaluating individual malignancies are needed to assess the impact on long-term survival of early detection of pulmonary metastases with CT.
Humans↗
Effect of constant light exposure on circulating gonadotrophin levels and hypothalamic gonadotrophin-releasing hormone (GnRH) content in the ovariectomized pony mare.
Melatonin is thought to play a role in relaying photic information to the central nervous system as part of the seasonal reproductive cycle of the mare. However, the mechanisms by which melatonin may act are unknown. Therefore, this study was designed to determine whether exposure to constant light would, by reducing circulating melatonin concentrations, have any effect on hypothalamic gonadotrophin-releasing hormone (GnRH) content and circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Blood samples were collected for 12 h at 15-min intervals from 8 ovariectomized (OVX) pony mares under ambient light conditions (12 h light, 12 h dark, October 6). Animals were then placed under representative ambient light (12 h light, 12 h dark; control, n = 4) or constant light (24 h light, 0 h dark; treatment, n = 4) in light-controlled rooms. Blood samples were collected daily and on experimental Days 14, 21 and 28 samples were collected at 15-min intervals for 12 h for analysis of circulating LH and melatonin (Bleed 2, 3 and 4, respectively). All animals were killed on Day 28 (following Bleed 4) and the hypothalami were collected. Mares exposed to constant light had significantly higher (P less than 0.05) LH concentrations in daily blood samples and showed significantly (P less than 0.05) higher LH concentrations during frequent sampling periods on Days 14 and 21 (Bleeds 2 and 3) compared with control mares. FSH did not differ significantly among groups in the daily samples. GnRH content was 1.5994 +/- 0.325 and 0.9457 +/- 0.193 pg/mg protein (treatment and control respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Intra-follicular and peripheral steroid characteristics during vernal transition in the pony mare.
This experiment investigated steroid production by ovarian tissues, in vitro, of pony mares during vernal transition from anoestrus to the breeding season. Follicular dynamics were monitored to detect the first, second, third or fourth transition follicle, greater than or equal to 30 mm diameter or the first large post luteal follicle of the breeding season. Twenty-four hours after a large follicle was detected, theca (T) and granulosa (G) tissues were harvested. Separate and co-incubations of these tissues were conducted to determine steroid production in early transition (ET), late transition (LT) and pre-ovulatory (OV) follicles. Peripheral plasma and follicular fluid steroids and gonadotrophins also were assayed. Peripheral plasma oestradiol concentrations increased from ET to LT and again from LT to OV in parallel with tissue production and follicular fluid content. Androgen production increased from LT to OV whereas progesterone production showed no change, thereby indicating a possible failure of 17-alpha steroid hydroxylase in ET follicles. Examination of tissue steroid secretion rates revealed that granulosa was the major site of oestrogen production, whereas theca secreted greater amounts of androgen.
Androstenedione↗
Interleukin-2 therapy for advanced renal cell carcinoma: radiographic evaluation of response and complications.
To evaluate the radiographic manifestations of the response of intrathoracic metastases to and the toxicity of interleukin-2 (IL-2) therapy, the chest radiographs and computed tomographic scans of 43 patients receiving 103 cycles of IL-2 treatment and lymphokine-activated killer cells for advanced renal cell carcinoma were reviewed. Among these 43 patients, 31 could be assessed for response of metastatic disease: Complete response was seen in one (3%), partial response in 11 (36%), mixed response in nine (29%), progressive disease in five (16%), and stable disease in five (16%). In 103 treatment cycles radiographic evidence of toxicity included pleural effusions (45.6%), pulmonary edema (21.4%), increased cardiothoracic ratio (16.5%), increased azygos vein diameter (9.7%), pericardial effusion (5.8%), and hilar lymphadenopathy (1.0%). These toxic effects could be distinguished from metastatic disease by a temporal relationship to treatment cycles. A favorable response to IL-2 therapy was significantly correlated (P less than .001) with the presence of pleural effusions.
Adult↗
Septic pulmonary embolism complicating a central venous catheter.
Bacteremia is a recognized complication in patients with indwelling central venous catheters. More recently pulmonary embolism in such patients has also been described. Despite abundant clinical experience with these devices, to our knowledge, septic pulmonary embolism has not been reported in adult patients. This case illustrates such a complication.
Adolescent↗
Peripheral carcinoid tumor of the lung: CT diagnosis.
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Adult↗
Pleural effusions: pathogenesis, radiologic evaluation, and therapy.
The imaging of pleural effusions by plain radiography, sonography, computed tomography (CT), and magnetic resonance imaging (MRI) has greatly facilitated the planning of both initial diagnostic thoracentesis and subsequent therapeutic management. The normal anatomy and physiology of the pleura, the pathogenesis of effusions, and the clinical criteria for classifying effusions are briefly summarized. The usefulness of each imaging modality is then discussed, particularly with regard to the problems of detecting small effusions, identifying loculation of fluid, distinguishing pleural from intraparenchymal disease, and assessing the extent to which a pleural process has become organized.
Diagnostic Imaging↗
The pathogenesis, radiologic evaluation, and therapy of pleural effusions.
Radiology has played a pivotal role in the management of patients with pleural effusions. By confirming the presence of an effusion and providing information regarding the size and distribution of fluid, chest radiography greatly facilitates initial diagnostic thoracentesis. Identification of even small effusions is important because these commonly occur and may have clinical significance. The development of improved antibiotics and a wider range of interventional techniques has increased the reliance on the radiologic imaging of pleural disease in order to plan appropriate therapy. The newer imaging modalities of CT and sonography have proved to be particularly valuable in detecting small effusions and demonstrating single or multiple loculations. Additional features, such as the degree to which a pleural process has become organized and whether there is adjacent lung parenchymal disease, are well assessed on CT. Experience with MR has been limited, but preliminary data suggest that it may be a valuable addition and/or alternative to CT.
Animals↗
Cryotherapy for experimental Pseudomonas keratitis.
The effectiveness of cryotherapy alone and in combination with topical tobramycin sulfate therapy for experimental Pseudomonas keratitis was determined in guinea pigs and rabbits. Results were evaluated quantitatively by determining numbers of viable bacteria surviving in corneas. A brass probe cooled to--79 degrees C and applied directly to infected corneas for six seconds resulted in an immediate 99.9% reduction in bacteria. One freeze-thaw cycle followed by topical tobramycin therapy was significantly more effective than tobramycin therapy alone in five of six strains tested. None of the corneas treated with tobramycin alone demonstrated no growth, whereas 24 of 42 of these infected corneas showed no growth after the combination treatment. We conclude that cryotherapy alone had a rapid bactericdal effect on experimental Pseudomonas keratitis and that it significantly potentiated topical antibiotic therapy for most strains.
Animals↗
Comparison of therapeutic routes in experimental Pseudomonas keratitis.
We determined the efficacy of tobramycin administered by topical, intramuscular, and subconjunctival routes in guinea pigs and rabbits with experimental Pseudomonas keratitis. The topical route of administration was consistently more effective than either subconjunctival or intramuscular routes. Subconjunctival injection of antibiotic did not enhance the effectiveness of topical therapy in either guinea pigs or rabbits. Intramuscular tobramycin was more effective than saline in guinea pigs with keratitis but not in rabbits with keratitis.
Administration, Topical↗
Experimental bacterial keratitis in neutropenic guinea pigs: polymorphonuclear leukocytes in corneal host defense.
Quantitative techniques were used to determine the relative concentrations of viable bacteria and polymorphonuclear leukocytes (PMNs) in the corneas of neutropenic and non-neutropenic guinea pigs with experimental bacterial keratitis induced with three strains of Pseudomonas aeruginosa. Neutropenia was produced by whole-body X-irradiation 1 week before infection. Significantly greater numbers of bacteria were present in the cornea of neutropenic animals 48 h after infection than were present in the corneas of non-neutropenic animals. The same was true 24 and 48 h after infecting animals with Staphylococcus aureus. Examination of histological sections showed that fewer PMNs were present in the corneas of infected neutropenic animals than in the corneas of infected non-neutropenic animals. Radiolabeling of PMNs confirmed a significant reduction in PMN concentration in the corneas of infected neutropenic animals. Tears and the corneal epithelium appear to be the most important elements protecting the cornea against local invasion by bacteria. However, once bacterial keratitis is established, PMNs play a role in limiting bacterial multiplication.
Animals↗
Experimental Pseudomonas keratitis in guinea-pigs: therapy of moderately severe infections.
We have previously shown that antibiotic therapy of experimental Pseudomonas keratitis was more effective in early moderate infections than in late severe infections. The purpose of this study was to determine the relative efficacies of various drugs, routes, and vehicles in the treatment of moderately severe infection. As in the late severe infections, the most consistently effective regimen was an aminoglycoside applied topically in solution. No synergistic or additive effect was observed with a combination of aminoglycoside given topically and a penicillin given intramuscularly. Topical therapy with antibiotic in ointment was less effective than topical therapy with antibiotic in solution.
Administration, Topical↗
Topical tobramycin therapy of experimental Pseudomonas keratitis: an evaluation of some factors that potentially enhance efficacy.
We evaluated several therapeutic modifications in an attempt to improve efficacy of topical therapy with tobramycin of experimental Pseudomonas keratitis in guinea pigs. Removal of corneal epithelium enhanced efficacy of topical therapy with 0.3 mg/ml and 3 mg/ml tobramycin sulfate but did not influence therapy with 40 mg/ml or 400 mg/ml tobramycin. The highest concentration of antibiotic was the most effective; 7 of 12 infected corneas treated with 400 mg/ml tobramycin were sterile in 48 hours. Therapy begun soon after the infection was established, when there were relatively few organisms present, was more effective than therapy begun later, when there were many more bacteria in the cornea. Our results are consistent with a basic therapeutic concept. The most effective regimen is one that achieves the highest safe concentration of antibiotic at the site of infection as early in the course of infection as possible.
Administration, Topical↗
Corticosteroid in experimentally induced Pseudomonas keratitis: failure of prednisolone to impair the efficacy of tobramycin and carbenicillin therapy.
The effect of prednisolone on tobramycin and carbenicillin therapy for experimentally induced Pseudomonas keratitis was evaluated. Results were assessed quantitatively by determining the number of bacteria that survived in the cornea. Simultaneous administration of prednisolone did not adversely alter results of treatment with carbenicillin or tobramycin. In another trial, pretreatment with prednisolone for 48 hours before antibiotic therapy was begun did not change significantly the results of therapy with intramuscular tobramycin or carbenicillin. We conclude that corticosteroid therapy does not affect adversely results of antibiotic therapy with tobramycin or carbenicillin in this experimental model.
Administration, Topical↗