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Biomedical subjects

D C Jones

Publications and source records attributed to D C Jones.

At least 91 records · Page 5Linked to original sources
PubMed1987

High dose para-aortic lymph node irradiation for gynecologic cancer: technique, toxicity, and results.

A technique for high dose (5600-6100 cGy) extended field irradiation to the para-aortic lymph nodes is described. Fourteen patients have been treated with this technique, of whom 10 have had histologic confirmation of para-aortic node metastases. With follow-up ranging from 11 to 78 months, 7 of 14 patients are alive and clinically cancer-free. Acute effects of extended field treatment on patient weight and circulating blood counts are analyzed, and late treatment morbidity assessed. The findings suggest that such treatment, executed with modern equipment and appropriate technique, is not significantly more hazardous than pelvic irradiation, and can result in a substantial probability of disease-free survival.

Adult↗
PubMed1987

The utility of MR in planning the radiation therapy of oligodendroglioma.

Newer methods of radiation therapy for treating oligodendroglioma after surgical resection have produced promising results using high doses of radiation. However, these doses are close to those that cause necrosis of normal brain, making the accurate spatial localization of tissue at risk for containing tumor cells more important. Because MR imaging is superior to CT in detecting some types of intracranial disease, nine patients with oligodendroglioma were studied with both MR and CT. Results were compared with surgical findings. In six cases, MR identified some tumor volume found during surgery that was not detected by CT. In addition, the interface between abnormality (tumor plus edema) and normality was depicted much more clearly by MR than by CT in most cases. Such superior depiction of the margins of abnormality is important for radiation therapy planning because of the known tendency of oligodendroglioma to infiltrate adjacent edema, making all areas of abnormality potential tumor-bearing tissue. Finally, MR showed normal brain tissue in areas considered suspicious by CT, because they were not well seen on CT in several patients. In these cases of low-grade oligodendroglioma, MR was believed to be superior to CT in providing information needed for radiation therapy planning because of its ability to distinguish tumor and adjacent edema (considered tissue at risk for containing microscopic tumor) from contiguous normal brain.

Adult↗
PubMed1986

Communication patterns between nursing staff and the ethnic elderly in a long-term care facility.

The purpose of this study was to examine verbal communication interactions between nursing staff and the elderly residents in a long-term care facility. Three groups of elderly were studied and compared. These were immigrant, Canadian-born, and Anglo-born elderly. Non-participant observation and tape recordings were the methods by which data were collected. Findings were transcribed and quantified under headings of 'words spoken', 'commands given', 'statements made', and 'questions asked and answered'. Significant differences in the observed interaction were found between groups. The findings indicate the need for nurses to be aware of the implications of ethnicity in caring for the elderly, and also for further communication studies in this area.

Aged↗
PubMed1985

Evaluation of the genotoxic potential of certain pesticides used in Pakistan.

The mutagenicity of fifteen insecticides, five fungicides, four herbicides, and an acaricide commonly used in Pakistan was evaluated by employing thirteen short-term bioassays. The genetic endpoints used included point or gene mutation, primary DNA damage, and chromosomal effects. Initially, all pesticides were tested in a "core" battery of four in vitro bioassays. A carefully selected group among these chemicals was retested in higher level test systems to confirm the results obtained in the initial phase. Of the pesticides tested, only a small portion consistently displayed mutagenicity across test systems. The Saccharomyces cerevisiae bioassays detected mutagenicity for the largest number of pesticides. The Salmonellaces typhimurium strain, TA100, was able to detect genetic activity in all of the pesticides that produced positive results in this bioassay. The cytogenetic effects observed from the Vicia faba root assay were consistent with those obtained in mammalian cells in culture. All pesticides which displayed mutagenicity were not carcinogenic in animal bioassays but, in general, mutagenicity in a battery of short-term bioassays was a reliable indicator of the carcinogenic potential in animals. A simple test battery is proposed for evaluating the genetic potential of agricultural pesticides.

Animals↗
PubMed1985

Aberrant wave forms to pattern reversal stimulation: clinical significance and electrographic 'solutions'.

Aberrant wave forms (AWFs) which are pattern visual evoked potentials (PVEPs) with ambiguous P2 peaks, were found in 13.7% of our patient population and not in our control group. The distribution of AWFs among the clinical entities of chronic myelopathy, questionable early MS, MS without visual lesions, MS with visual lesions and other neurological disorders, were similar to that of normally formed PVEPs with delayed P2 peaks. AWFs therefore appear to have a similar clinical significance to that of delayed, normally formed PVEPs, whether or not their latencies are within the normal range. Electrographic fields of non-aberrant PVEPs with well defined P2 peaks were studied to define the following obligate P2 characteristics: P2 always attained highest amplitude at the midline occipital position (Ox), hemifield stimulation using Fz as a reference always evoked a larger NPN complex over the hemisphere ipsilateral to stimulation than over the contralateral hemisphere. Multiple-channel analysis of both fullfield and hemifield stimulation and bipolar transverse montages reconstructed from referential recordings were employed to identify the P2 peak in AWFs. Bipolar reconstruction identified the P2 peak in 61% of all instances in which it was employed while hemifield stimulation did so in 84% of instances. In the 82 instances in which both were employed, hemifield stimulation identified the P2 in 84% as compared to only 33% for bipolar reconstruction. Therefore, although bipolar reconstruction may often identify the P2, hemifield stimulation is more effective for particularly complex situations.

Adolescent↗
PubMed1985

MR imaging in radiation therapy planning. Work in progress.

Magnetic resonance (MR) imaging may provide information about tumor location, extent, and margins unavailable from other imaging modalities. The impact of MR on radiation therapy planning was investigated in this study. Thirty patients about to undergo radiation therapy underwent routine radiography and computed tomography (CT) to define the extent of their disease. A radiation therapy plan, including portal placement and size, was drawn up based on this information alone. The patients also underwent MR studies. After the original therapy plan was created, the MR study results were made available to the radiation therapist. In 53% (16/30) of the cases, MR information led to a measurable change in the therapy plan; in an additional 33% (10/30), MR information increased confidence in the original plan. MR may become a necessary procedure for radiation therapy planning in many cases.

Humans↗
PubMed1985

Subluxation of the knee as a complication of femoral lengthening by the Wagner technique.

Twenty-one patients with leg-length inequality underwent femoral lengthening using the Wagner technique. When reviewed, seven were found to have varying degrees of posterior subluxation of the knee. Critical assessment demonstrated that each of these was associated with a hypoplastic femur. It is postulated that posterior displacement of the tibia on the femur occurred as a result of the distal femoral and intraarticular bony deficiencies.

Adolescent↗
PubMed1984

Murine forebrain anomalies induced by coxsackievirus B3 variants.

Neonatal or 7-day-old mice inoculated intracranially with either of two temperature-sensitive mutants (ts1, ts6) or the parent coxsackievirus B3 (CVB3) subsequently developed porencephaly or hydranencephaly. The forebrain anomaly induced depended upon age of the animal at inoculation and virus variant inoculated. Sections of brains from hydranencephalic mice revealed severe meningeal reactions, necrotizing encephalitis, and liquifactive necrosis in the cerebrum. No pathology was found in the pons, medulla, or cerebellum. Immunofluorescence studies with hyperimmune anti-CVB3 antiserum showed a random distribution of virus-infected cells in the cerebrum. Virus was recovered from several organs but little to no interferon and no anti-CVB3 neutralizing antibody were present in brain tissues. Availability of cells for replication of virus at the time of inoculation and replicative properties of each virus likely contributed to the outcome. Thus, forebrain anomalies resembling those found in infants can be induced in a murine model by select variants of coxsackievirus B3.

Animals↗
PubMed1984

Networking computergraphics: The Veterans Administration approach.

In addition to providing health care for veterans, the Department of Medicine and Surgery is responsible for health-related research, education, and training in the Veterans Administration. To accomplish these goals, Regional Learning Resources Services and Regional Medical Education Centers develop, design, and distribute instructional materials to facilitate continuing staff and patient education. This paper describes the organization and management of the computergraphics network that supports these efforts.

Computers↗
PubMed1983

Surgical stabilization of the spine in Duchenne muscular dystrophy.

The problem of real distress from the discomfort of collapsing scoliosis is predictable in Duchenne muscular dystrophy (DMD). Once the lumbar curve has exceeded 35 degrees, further progression is inevitable. A vital capacity, then, of 35% or more permits consideration of spinal surgery. Using these indications, 24 patients with DMD had long Harrington instrumentations and spinal fusions from S1 up to the upper thoracic spine (T4, 5, or 6). After two weeks recumbent, they were mobilized wearing a light spinal support in their wheelchairs. The complications encountered are described in detail. One patient died two years after his operation from dystrophic cardiomyopathy. With a follow-up period of four months to 42 months, the rest of these patients are well and sitting with comfort. The authors think that this experience indicates that prophylactic spinal fusion deserves consideration in the care planned for these patients.

Adolescent↗
PubMed1983

Failure of hypercholesterolemic serum to stimulate collagen synthesis in aortic smooth muscle cells from two species of nonhuman primates having different rates of collagen synthesis.

African green monkeys develop atherosclerotic lesions that are more fibrous than those found in rhesus monkeys. The purpose of this study was to determine if this difference in collagen content could be related to a specific effect of a serum component on collagen synthesis by cells of the arterial wall or to inherent differences in the arterial smooth muscle cells from these two nonhuman primate species. Aortic smooth muscle cells were grown in tissue culture from both rhesus and African green monkeys and incubated for up to 48 hr with different concentrations of serum from normal or hypercholesterolemic animals. Collagen synthesis was determined by measuring the conversion of radiolabeled proline to hydroxyproline. Total protein synthesis was determined from the incorporation of radiolabeled proline into total proteins. Hypercholesterolemic serum from either species did not stimulate collagen or total protein synthesis in either African green or rhesus monkey smooth muscle cells. This was true even though under the same conditions other studies have shown that hypercholesterolemic serum produces an increase in cellular cholesteryl ester content. This suggests that hypercholesterolemia per se is not directly responsible for the stimulation of collagen synthesis typically seen in atherosclerotic lesions. African green monkey smooth muscle cells synthesized from 1.7 to 3.4 times more collagen than did rhesus monkey smooth muscle cells, while total protein synthesis was similar for both cell types. This suggests that the greater amounts of collagen present in the atherosclerotic lesions from African green monkeys may be in part the result of an inherently greater potential of their smooth muscle cells to synthesize collagen.

Animals↗