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Biomedical subjects

D Swanson

Publications and source records attributed to D Swanson.

At least 37 records · Page 2Linked to original sources
PubMed1991

An enzyme-linked immunosorbent assay for detection of chronic subclinical Pasteurella pneumotropica infection in mice.

Serum samples from seventy-five, 3- to 12-week-old and 16 retired breeder male Swiss mice from a conventional colony with enzootic chronic subclinical Pasteurella pneumotropica infection were tested by enzyme-linked immunosorbent assay (ELISA) and Western blots for IgG antibodies to whole cell (WC) and lipooligosaccharide (LOS) antigens of P. pneumotropica. In 3- to 12-week-old mice, serum antibody levels to LOS exceeded those to the WC preparation. Western blots of sera from mice in this age group substantiated that a major component of the early IgG antibody response was directed against LOS antigens. Higher antibody levels to both antigen preparations in 3-week-old mice compared to mice 4 and 6 weeks old were interpreted as reflecting a decline in antibodies acquired from the dam. Active immunity indicative of infection was first detected at 8 weeks of age. Serum samples from retired breeder mice (28 weeks of age) also had substantial antibody titers to LOS but, in contrast to sera from mice in the younger age groups, retired breeders had significantly greater IgG reactivity to WC preparations than to LOS antigens. The superior specificity of the LOS antigen compared to the WC preparation in the ELISA was demonstrated by testing serum samples from retired breeder mice against WC and LOS antigens from P. ureae, P. multocida, and P. hemolytica. The reactivity of IgG against LOS antigens from these organisms was negligible, whereas substantial titers were evident to WC antigens. This ELISA, using LOS preparations as antigen, is a useful serologic assay for the detection of subclinical P. pneumotropica infection in mice.

Age Factors↗
PubMed1990

Comparative responsiveness of early chick neural tube neurons to muscle-conditioned medium, laminin, NGF and fibronectin.

Dissociates from the metencephalic basal plate of early chick embryo neural tubes containing the trigeminal (V) motor nucleus were cultured on substrates conditioned with appropriate target-derived muscle conditioned medium (MCM), laminin (LAM), MCM with nerve growth factor (NGF) in the medium, and fibronectin (FN). Comparisons were made of neuronal survival, the number of neurons with processes, and the length of processes elaborated. It was found that both MCM and LAM significantly enhanced survival and neuritic production from this population when compared to controls grown on a collagen-polyornithine substrate, but MCM surpassed LAM in these measures. When the neurons were grown on an MCM-conditioned substrate with an NGF-supplemented medium, no improvements were produced over the MCM or the NGF conditions alone. Therefore, the two do not appear to act in synergy, as NGF and LAM have been shown to do. FN produced no enhancement of any of the measures taken from this population. An ELISA analysis revealed no detectable LAM in the early target MCM. These results indicate that the specific responsiveness of this early neural tube population to its target MCM is not mediated by LAM, but the growth-enhancing component acts in a similar manner, although its influence is more potent.

Animals↗
PubMed1990

Postoperative spindle cell nodule of the prostate and bladder.

Postoperative spindle cell nodule of the prostate and bladder (a rare lesion often misinterpreted as sarcoma) is important to recognize. The nodule consists of a reactive proliferation of spindle cells occurring up to several months after a lower genitourinary tract procedure, such as transurethral resection or biopsy. We report on 5 patients with a spindle cell nodule after a prior operation on the prostate or bladder. Of these patients 2 initially were diagnosed as having leiomyosarcoma, including 1 who underwent radical cystoprostatectomy. Because of the potential for inappropriate treatment the clinician must be aware of this entity so that he might question the diagnosis and raise the possibility of a postoperative spindle cell nodule whenever sarcoma is diagnosed after recent surgical instrumentation for a nonmesenchymal lesion in the genitourinary tract.

Aged↗
PubMed1990

Indications for office radiographs.

Radiology is an essential part of the family physician's office practice. Like most diagnostic tools, radiographs can provide valuable information, but they also have the potential to be abused. One of the first tasks in ensuring optimal use of any procedure is to establish criteria for proper patient selection. This article is a review of general and specific indications for office radiographs on both symptomatic and asymptomatic patients based on published expert consensus and studies that have examined indications for radiographs using clinical criteria. For symptomatic patients, indications are discussed for the following radiographs: extremities (traumatic and nontraumatic), skull, abdomen, chest, orbits, sinuses, facial bones, and spine. Indications for asymptomatic patients are discussed with specific attention to lumbosacral spine and chest radiographs. When appropriate indications are followed, the physician can avoid the problem of overuse and its consequent radiation and economic burdens, as well as the problem of underuse with its risk of incomplete evaluation.

Extremities↗
PubMed1990

Interpreting office radiographs. A guide to systematic evaluation.

Office radiographs are important diagnostic tools for most family physicians, and most family physicians believe that they should be capable of interpreting 90% of these films without referral to a radiologist. Optimal use of these radiographs requires that patients are appropriately selected, that the examination is adequately conducted, and that the films are accurately interpreted. Interpretive accuracy is enhanced if radiographs are analyzed by physicians skilled in observing and interpreting them and if the images are examined in a logical, systematic manner to minimize observer bias. A systematic search pattern is proposed to facilitate family physicians' interpretations for the most common office radiographs: chest, extremities, abdomen, skull, and spine.

Clinical Competence↗
PubMed1990

Acridine orange flow cytometric analysis of renal cell carcinoma. Clinicopathologic implications of RNA content.

To explore the potential role that ribonucleic acid (RNA) content analysis may have in the assessment of primary renal cell carcinomas (RCC), biparametric flow cytometric (acridine orange) measurements for DNA/RNA were obtained on 108 fresh neoplastic specimens. RNA content was divided into low and high groups, based on the average RNA content in normal kidney controls. High RNA content was significantly correlated with aneuploidy, high proliferative index, high nuclear grade, cytoplasmic granularity, and large tumor size. No correlation was found between RNA content and patients' sex, race, and clinical stage of the carcinomas. When diploid RCCs were separately analyzed, high RNA content was correlated with high nuclear grade, large tumor size, high clinical stage, and cytoplasmic granularity. There was no correlation between RNA content and the patient's sex or race or the neoplasm's proliferative index. Of the 16 patients that relapsed (5 diploid and 11 aneuploid), four of the diploid and all 11 aneuploid neoplasms displayed high RNA content. The authors' data show that RNA may be a valuable objective and quantitative parameter in the clinicopathologic assessment of RCC.

Acridine Orange↗
PubMed1989

Clinical and radiological correlation of retroperitoneal metastasis from nonseminomatous testicular cancer treated with chemotherapy.

Forty patients with retroperitoneal metastasis from nonseminomatous testicular cancer treated with chemotherapy were retrospectively studied to (1) evaluate the predictive value of mass size as detected by computerized tomography (CT) as an indicator for postchemotherapy surgery and (2) determine the factors that influence relapse. Patients received two further courses of chemotherapy after their serum biomarkers became normal and computed tomography indicated a complete response or presence of a residual but stable mass. We found that patients with initial metastases less than 2 cm had a low frequency (14%) of residual masses after chemotherapy, vs. 59% for those with masses of 2-5 cm and 75% for those with masses of greater than 5 cm (P = 0.03). Of 22 patients with primary embryonal carcinoma, three of seven (43%) with residual masses after chemotherapy had mature teratoma at surgery. Six patients had small (1-2 cm) residual abnormalities that were not removed, and three of these patients relapsed. In conclusion, increasing size of retroperitoneal metastasis by CT scan predicts for increased likelihood of a residual mass after chemotherapy; patients who have a residual mass greater than or equal to 1 cm require retroperitoneal lymphadenectomy after chemotherapy, whether the tumor histology is embryonal carcinoma or teratoma. The role of surgery for patients who have residual retroperitoneal masses less than 1 cm after chemotherapy could not be determined from our study.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Diagnosis of discitis by SPECT technetium-99m MDP scintigram. A case report.

A 29-year-old male presented with a two month history of intermittent low back pain following a febrile illness. Two planar bone scans performed with Tc-99m MDP were normal despite roentgenographic and SPECT scintigraphic evidence of discitis. This case demonstrates the increased sensitivity of SPECT in the diagnosis of discitis.

Adult↗
PubMed1986

Synthesis of a myelin-like membrane by oligodendrocytes in culture.

We have prepared highly purified cultures of rat oligodendrocytes by a modification of the procedure of McCarthy and de Vellis [1980]. By utilizing a substratum derived from lysed glia and a calf serum-containing medium with a high concentration of transferrin, the oligodendrocyte cultures display a high degree of purity, the ability to survive several months of culture, and a striking ability to produce a myelin-like membrane. We have examined the production of this myelin-like membrane using immunocytochemical and biochemical probes as well as an extensive morphological examination at the electron microscopic level. The membrane appears to be produced in a similar developmental pattern to that observed in vivo and it has the structural characteristics of loosely packed central nervous system myelin.

Animals↗
PubMed1986

Cyclic chemotherapy with cyclophosphamide, doxorubicin, and cisplatin plus vinblastine and bleomycin in advanced germinal tumors. Results with 100 patients.

One hundred patients with advanced mixed germ-cell tumors were treated with cisplatin, cyclophosphamide, and doxorubicin alternating with vinblastine and bleomycin (cyclic CISCAII/VBIV). The chemotherapy achieved an 89 percent continuous disease-free status (85 percent with chemotherapy, 4 percent with chemotherapy plus surgery). The mean follow-up duration for patients with continuous complete remission was 132 weeks (+/- 6.2), with a median of 126 weeks. Multivariate analysis using a stepwise logistic regression of prognostic variables revealed that a high serum level of the beta subunit of human chorionic gonadotropin (more than 50,000 mIU/ml) was of prognostic significance, followed by the Samuels staging criteria and extragonadal origin of disease. Thirty-two patients underwent exploratory surgery after they had had two courses of chemotherapy beyond the establishment of a stable mass and absent serum biomarkers. No viable cancer was found at exploration, and all patients remain alive and free of disease. The acute toxicity of the cyclic chemotherapy was formidable, but only one patient had a fatal complication. Thirty-six percent of the CISCAII courses and 44 percent of the VBIV courses were associated with leukopenic fever, and 5 percent of the CISCAII courses and 8 percent of the VBIV courses were associated with culture-positive infection. Long-term toxicity was unusual: bleomycin lung toxicity 1 percent, cardiac toxicity 1 percent. CISCAII/VBIV cyclic chemotherapy is superior to cisplatin, vinblastine, and bleomycin (PVB) chemotherapy; it results in a higher complete remission rate, a lower relapse rate, and a lower incidence of long-term complications. Patients with a high risk of failure of PVB chemotherapy (Samuels stage IIIB3 to IIIB5) or with extragonadal tumors should be treated with CISCAII/VBIV.

Adolescent↗
PubMed1985

Cyclophosphamide, doxorubicin and cisplatin chemotherapy for patients with locally advanced urothelial tumors with or without nodal metastases.

Thirty-eight patients with primary urothelial tumors recurring in the pelvis or nodal presentation were treated with intravenous or intra-arterial cyclophosphamide, doxorubicin and cisplatin chemotherapy. The 38 patients were selected owing to unresectability by local criteria (12 patients) or by virtue of nodal metastases (26 patients). Histologically, the patients either had pure transitional cell carcinoma (29), transformation to a histological subtype of transitional cell carcinoma (7) or pure squamous cell carcinoma (2). An over-all 50 per cent complete remission rate was achieved with an 18 per cent objective pelvic response rate, and 32 per cent failed to respond to chemotherapy. Responses by histological subtype revealed that patients with pure transitional cell carcinoma had a 62 per cent complete remission rate, those with transitional forms had a 14 per cent complete remission rate and none with squamous cell carcinoma responded to chemotherapy. A significant difference in the incidence of responses among patients with transitional carcinoma and those with transition forms was seen (p less than 0.02). Complete remissions were independent of disease site. Nineteen patients achieved a complete remission with a mean duration of 86 weeks and median of 81 weeks (range 33 to 172 weeks). Toxicity of the chemotherapy was moderate with a high incidence of peripheral neuropathy and leukopenic infections. No deaths of chemotherapy were encountered. Patients with locally advanced or metastatic transitional cell carcinoma of the urothelium to lymph nodes can benefit from intravenous and intra-arterial cyclophosphamide, doxorubicin and cisplatin chemotherapy.

Adult↗
PubMed1985

Antitumor activity of recombinant-derived interferon alpha in metastatic renal cell carcinoma.

Fifty-six patients with metastatic renal cell carcinoma (RCC) were treated with recombinant DNA-derived interferon alpha (rIFN alpha A). The first 30 patients were randomized between doses of 2 X 10(6) U/m2 and 20 X 10(6) U/m2 intramuscularly daily. No complete (CR) or partial (PR) remissions were achieved in 15 patients receiving the low dose. In contrast, 27% of those receiving the high dose achieved CR or PR. Subsequently, 26 additional patients were given the high dose and achieved a 31% response rate. Remissions lasted from 1 to more than 12 months (median, 3 months). Responses occurred predominantly in lung parenchyma or mediastinal node metastases. Toxicity of the high dose required dose reduction in 50% of the patients. Neutralizing antibodies to rIFN alpha A developed in seven of 12 responsive (58%) and nine of 29 (31%) nonresponsive patients (P = greater than .5). The median duration of remission among the antibody-positive and antibody-negative patients were 2 and 10 months, respectively (P = .009). The clinical significance of the antibodies to rIFN alpha A remains unclear, but the coincidence between the detection of antibodies and the early relapse of the disease in some responsive patients suggests that these antibodies may abrogate the biologic activity of rIFN alpha A. This effect, however, was not associated with adverse clinical sequelae.

Adult↗
PubMed1985

Improved survival with cyclic chemotherapy for nonseminomatous germ cell tumors of the testis.

Forty-eight patients with advanced nonseminomatous germ cell tumors of the testis received a combination of cyclophosphamide, doxorubicin, and cisplatin (CISCAII) and a modified combination of vinblastine and bleomycin (VBIV) cyclic chemotherapy. Forty-four (92%) have achieved a complete remission. No patient in complete remission has relapsed with a mean follow-up of 139.0 weeks (SEM 7.0 weeks). The patients were stratified according to the modified Samuels clinical staging criteria. Thirty-seven (77%) had advanced disease (stage III-B3 to III-B5), ten of whom had advanced visceral non-lung disease (stage III-B5). Chemotherapy was individualized by tumor volume and response to therapy. Two courses were delivered after complete remission or the development of a stable mass with negative serum biomarkers. Twenty-four patients (50%) were explored for a persistent and stable mass. No viable cancer was found; 15 (62%) had mature teratomas and nine (38%) had scar. No patients suffered from doxorubicin cardiotoxicity, clinical pulmonary bleomycin toxicity, or persistent cisplatin renal failure. Four patients died. One patient, an unrecognized drug abuser, died of toxicity. Three with far-advanced tumors died of progressive disease. CISCAII/VBIV cyclic chemotherapy is superior to chemotherapy with vinblastine, bleomycin, and cisplatin, resulting in a 92% complete remission rate and a significant reduction in long-term toxicity.

Adolescent↗