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Biomedical subjects

P Dixon

Publications and source records attributed to P Dixon.

At least 19 recordsLinked to original sources
PubMed1992

Phase I trial of the murine monoclonal anti-GD2 antibody 14G2a in metastatic melanoma.

In a phase I trial, 12 patients with GD2 antigen-positive metastatic melanoma received the murine anti-GD2 monoclonal antibody 14G2a. The monoclonal antibody was administered in four doses over an 8-day period with total dose ranging from 10 to 120 mg. All patients receiving greater than 10 mg of 14G2a experienced transient abdominal/pelvic pain during the antibody infusion. Five patients had a delayed extremity pain syndrome following the third and fourth antibody infusion. Four of the five patients developed neurological toxicity, including two patients with significant although reversible motor neuropathy. Two of the patients developed hyponatremia secondary to a syndrome of inappropriate antidiuretic hormone. All 12 patients developed high levels of human anti-14G2a antibody. The plasma half-life of 14G2a was 42 +/- 6 (SD) h. One patient each had a partial response, mixed response, and stable disease, respectively. The very modest antitumor activity accompanied by dose-limiting neurological toxicity at total doses greater than 80 mg may restrict the clinical utility of murine 14G2a.

Antibodies, Monoclonal↗
PubMed1991

Conservative treatment of an incomplete longbone fracture of a hindlimb of four horses.

Four horses with an incomplete fracture of a hindlimb longbone were examined. In two, the tibia had been fractured by external trauma. In the other two horses proximal metatarsal 3 had fractured during normal activity. The diagnoses were made radiographically and the horses were treated conservatively by box rest. The fractures healed satisfactorily and the horses became sound.

Animals↗
PubMed1991

Pions--the potential for therapeutic gain in locally advanced prostate cancer: dose escalation and toxicity studies.

Since 1982, 49 patients with locally advanced carcinoma of the prostate have been treated with pion radiotherapy in tolerance and tumor response studies. The relative biological effectiveness (RBE) was confirmed as 1.5 for both acute and late effects, a figure expected on the basis of animal and human studies. The radiation dose has been safely escalated to tolerance, which is estimated to be 37.5 Gy pi in 15 fractions (volume less than 500 cc), and 36 Gy pi in 15 fractions (volume 500-800 cc). Severe acute toxicity occurred in 6% and severe chronic toxicity in 4%, figures comparable to those seen with conventional radiotherapy. The equivalent photon doses are approximately 78 Gy in 39 fractions and 73 Gy in 36 fractions, respectively. That this high dose can be delivered with no increase in toxicity is a reflection of smaller volume radiotherapy achieved by exploiting the dose distribution and biological characteristics of pions. Local response rates of 94% are reported. A Phase III study is now under way.

Adenocarcinoma↗
PubMed1991

Effects of display luminance, stimulus meaningfulness, and probe duration on visible and schematic persistence.

Partial report performance is conceived of as consisting of two independent sources of information: visible persistence and schematic persistence. Following the work of Di Lollo and Dixon (1988), these two sources of information were separated experimentally by varying interstimulus interval and stimulus onset asynchrony independently. In the present experiment we asked whether visible persistence and schematic persistence would be affected by display luminance, stimulus meaningfulness, or probe duration. The results were fit accurately by an extension of the Di Lollo and Dixon independent-decay model in which display luminance affected visible persistence but stimulus meaningfulness and probe duration affected neither form of persistence directly.

Adult↗
PubMed1991

AIDS and cancer pain treated with slow release morphine.

The use of slow release morphine was compared between those with cancer and those with advanced HIV disease in two retrospective studies covering a total of 512 patients at home. Pain was found to be less severe in HIV/AIDS but still requiring opioid use in over a third of patients of which 14% needed subcutaneous diamorphine infusion when seriously ill at home. Slow release morphine was used by 45% of those with cancer and 17% of those with HIV/AIDS. It was found to be a simple and convenient preparation for use at home with most patients never needing more than 30 mg twice daily. Half the cancer patients prescribed slow release morphine were able to take it until the day of death.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Tennis injuries.

An unfit tennis player is more likely to suffer an injury. The tennis player should be well prepared physically and possess a sound technique. Attention should be paid to playing gear to minimise the possibility of injury.

Biomechanical Phenomena↗
PubMed1990

Ultrasonographic diagnosis of a fetal abdominal mass: a case of a mesenchymal liver hamartoma and a review of the literature.

A case of a prenatally recognized hepatic mesenchymal hamartoma is presented and the literature reviewed. These tumors are benign and usually present in early infancy with symptoms that are related to the mass effect on adjacent organs. Radiologic methods used in the past to image this tumor include angiography and ultrasound. However, there is no specific radiologic finding, and, therefore, the diagnosis is usually made during surgery. Once the tumor is removed, the prognosis is generally good. With the increasing use of high resolution ultrasound in prenatal diagnosis, this rare tumor should be considered in the differential diagnosis of any multicystic mass found in the fetal abdomen. The recognition of a mass should then alert the physician to the need for early neonatal intervention.

Adult↗
PubMed1986

Attention and interference in the perception of brief visual displays.

When a single target was displayed 100-200 ms after a five-item array, observers were remarkably poor at deciding whether or not the target was in the array; performance was much better when the target either preceded the array or followed it by a longer interval. This effect was independent of a number of visual display parameters, suggesting that it was not due to visual contour interaction. In addition, visual similarity did not interact with the effect, indicating that it probably did not occur during item identification either. However, when observers added one to a digit target before deciding whether it occurred in the array, the effect was substantially reduced. The results suggested a model in which abstract identity information about the target is confused with the array at certain temporal intervals. A quantitative version of this model fit the data quite well.

Attention↗
PubMed1985

Microcomputer applications in pathology research.

In a study of over 700 cases of uveal melanoma on file in the Department of Pathology of Wills Eye Hospital, a low-cost microcomputer using commercially available software (without modification) was used to: word process and edit this manuscript, create a patient file storage and retrieval system including the ability to create subfiles, merge files, and interchange file types, plot data points in several different graphic formats, transcribe and store information from microscopic tissue sections containing intraocular melanomas, and solve complex equations including statistical analysis. The results showed that over 150 different ophthalmologists contributed specimens to this data base. The mean age of the patients studied was 57 years and the tumors were evenly distributed according to sex and laterality of the eye. This study illustrates the feasibility of using a low-cost microcomputer and commercially available software in the study of a large patient data base.

Computers↗
PubMed1985

Preparatory clinical studies of Pi-mesons at TRIUMF.

Eighty patients have been treated with Pi-mesons (pions) at TRIUMF between 1979-1984. The patients had tumors rarely curable by standard methods and had no prior radiotherapy. The distribution by site included skin, metastatic nodules (13), brain, glioblastoma multiforme (32), pelvis, rectosigmoid (15), prostate (12), bladder (7), and ovary (1). The studies involve serial escalations of pion dose until maximum tissue tolerance is reached, monitoring the response at each dose increment. Sites were chosen for study where lack of local control is a significant cause of treatment failure with conventional radiation therapy. The low dose rate and the available beam access at TRIUMF limit the number of patients treated and the volume treatable. A 3-D treatment planning program is in use, and a 3-D display of the dose distribution delivered in brain tumor treatments has been developed using the PET scanner. In practice, new methods introduced for measurement of tissue response include tumor growth delay curves, fine-needle biopsy mapping, and PET scanning of brain tumors. The use of endoscopic assessment of the rectosigmoid region is emphasized. Treatment results of glioblastoma multiforme show that the median survival for patients treated to 125 pion cGy/fx is in the range of 187-198 days; for patients receiving 170 cGy per dose/fraction (fx) the range is 290-315 days, and for those receiving 200-220 cGy/fx the median survival is in excess of 290 days. For pelvic malignancies the local control obtained with doses of 2500 cGy or less was 50% in 12 assessable patients; it was 75% in 20 patients who had 3000 cGy or more.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗