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Biomedical subjects

R S Cox

Publications and source records attributed to R S Cox.

103 records · Page 6Linked to original sources
PubMed1979

Electron-beam therapy for mycosis fungoides: the Stanford University experience.

The use of high-dose electron-beam therapy for mycosis fungoides at Stanford University is reviewed. Since 1966, 140 patients have been treated in this fashion. Their clinical characteristics including initial extent of disease are reviewed. The results of routine staging studies are examined. Eighty-four percent of the patients achieved an initial complete remission; this was inversely related to the initial extent of skin involvement. The overall survival rate was 46% at 10 years with the major prognostic factor being the initial extent of skin involvement. Other factors which had an influence on the patient's progrnosis included the presence of palpable adenopathy, the patient's age, the achieving of an initial complete remission, the initial dose of electron-beam therapy, and the treatment with adjuvant topical mechlorethamine. The development of a rationale for the treatment of patients with all stages of mycosis fungoides based upon these clincal observations is discussed.

Adult↗
PubMed1975

Changes in morphine self-administration and morphine dependence after lesions of the caudate nucleus in rats.

Rats were trained to bar press for intravenous infusions of morphine sulfate during 1-hr daily test sessions. Small, centrally placed bilateral lesions of the caudate nucleus reduced rats of morphine self-administration to approximately one seventh of preoperative levels; postoperative rates were similar to preoperative rates when the postoperative unit infusion dose of morphine was one tenth of the preoperative dose. Caudate lesions also lowered the threshold dose at which morphine's rewarding property could be detected. Physical dependence was studied in other rats receiving a 3-day continuous infusion of morphine sulfate via implanted subcutaneous silicone reservoirs. Caudate lesions ameliorated withdrawal-induced weight loss and naloxone-induced "wet dog shakes". Both the self-administration and dependence data are consistent with the idea that morphine blocks dopaminergic transmission in the striatum.

Animals↗
PubMed1975

Modification of a rectilinear scanner to improve 67Ga scans.

A simple and inexpensive electrical modification of the pulse-height analyzers of the Ohio-Nuclear Model 84FD rectilinear scanner, which allows the use of wide pulse-height intervals, is described. The modified instrument is applied to 67Ga scanning, in which the increase acceptance of gamma rays produces scans of increased count density and improved image quality.

Gallium Radioisotopes↗
PubMedDate not supplied

The effect of delayed refrigeration on red blood cells, platelet concentrates and cryoprecipitable AHF.

The effect of delaying blood processing for six hours while maintaining it at ambient temperature was investigated. Blood drawn from volunteers on two occasions was processed immediately (I) or after a six-hour delay (D). The effects of the delay on the efficacy and safety of red blood cells, platelet concentrates and cryoprecipitable AHF were studied. There was a more rapid decrease in 2,3-DPG in the delayed group during 21 days of refrigerated storage. ATP levels declined at similar rates. 24-hour survival of 51CR-labeled autologous cells was slightly better (p = .05) in the (I) group but excellent for both. Total platelets, per cent recovery and pH at 72 hours were identical for both groups. All cultures were sterile. There was no difference in total AHF recovered or per cent recovery between the two groups. To increase the availability of blood components, a six-hour processing delay seems warranted.

Blood Platelets↗
PubMedDate not supplied

Response to pneumococcal vaccine among children with Hodgkin's disease.

Nineteen children with Hodgkin's disease were immuized with dodecavalent pneumococcal vaccine; the efficacy of vaccination, the duration of response, and the significance of the time of immunization in relation to splenectomy and subsequent irradiation and chemotherapy were investigated. Eight children were immunized before splenectomy, and 11 were immunized after splenectomy, irradiation, and chemotherapy. All children were irradiated, and all but two received chemotherapy with MOPP (nitrogen mustard, vincristine sulfate, procarbazine, and prednisone). Sera were assayed for antibodies to the 12 polysaccharide types in the vaccine. The group of children immunized before splenectomy had a significant antibody response to 67% of the antigens tested, whereas the group immunized after splenectomy responded to 40% of the antigens (P less than 0.0001). The duration of response was variable. Pneumococcal vaccine was more likely to provoke an immunologic response if administered before splenectomy than if administered after splenectomy, irradiation, and chemotherapy; however, the response was not uniform. A response to one antigen did not necessarily imply a response to other antigens. In the absence of a readily available assay to determine a protective antibody response, one cannot rely on the vaccine as the sole means of preventing pneumococcal infections in asplenic children with Hodgkin's disease.

Adolescent↗
PubMedDate not supplied

Stanford University institutional report. Phase I evaluation of equipment for hyperthermia treatment of cancer.

From September 16, 1981, through April 4, 1986, a total of 21 radiative electromagnetic (microwave and radiofrequency), ultrasound and interstitial radio-frequency hyperthermia applicators and three types of thermometry systems underwent extensive phantom and clinical testing at Stanford University. A total of 996 treatment sessions involving 268 separate treatment fields in 131 patients was performed. Thermal profiles were obtained in 847 of these treatment sessions by multipoint and/or mapping techniques involving mechanical translation. The ability of these devices to heat superficial, eccentrically located and deep-seated tumours at the major anatomical locations is evaluated and the temperature distributions, acute and subacute toxicities, and chronic complications compared. Average measured tumour temperatures between 42 degrees C and 43 degrees C were obtained with many of the devices used for superficial heating; average tumour temperatures of 39.6 degrees C to 42.1 degrees C were achieved with the three deep-heating devices. When compared to the goal of obtaining minimum tumour temperatures of 43.0 degrees C, all devices performed poorly. Only 14 per cent (118/847) of treatments with measured thermal profiles achieved minimum intratumoural temperatures of 41 degrees C. Fifty-six per cent of all treatments had associated acute toxicity; 14 per cent of all treatments necessitated power reduction resulting in maximum steady-state temperatures of less than 42.5 degrees C. Direct comparisons between two or more devices utilized to treat the same field were made in 67 instances, including 19 treatment fields in which two or more devices were compared at the same treatment session. The analyses from direct comparisons consistently showed that the static spiral and larger area scanning spiral applicators resulted in more favourable temperature distributions. Three fibreoptic thermometry systems (Luxtron single channel, four channel and eight channel multiple [four] probe array), the BSD Bowman thermistor system and a thermocouple system were evaluated with respect to accuracy, stability and artifacts. The clinical reliability, durability, and patient tolerance of the thermometry systems were investigated. The BSD Bowman and third generation Luxtron systems were found clinically useful, with the former meeting all of our established criteria.

Adult↗
PubMedDate not supplied

Heat loss and blood flow during hyperthermia in normal canine brain. I: Empirical study and analysis.

The effects of blood flow and thermal conduction during microwave hyperthermia were investigated in normal canine brain. Heating was accomplished with an external microstrip spiral antenna and temperature measurements were made using a multichannel fluoroptic thermometry system. In order to determine cooling rates, temperature measurements made during cooling were fitted with a model consisting of a constant value and an exponential term. Data from experiments in both perfused and non-perfused brains could be fitted with this simple model. The resulting cooling rates indicated that heat loss by conduction is comparable to that by blood flow. In another series of experiments, temperature measurements were made during several 1 min cooling intervals in which the power was shut off intermittently during a 35 min heating episode. Results were consistent with a 2-3-fold increase in blood flow rate which occurred gradually throughout the course of heating. Parameters that affect the determination of cooling rates are discussed in terms of the bioheat transfer equation. These investigations demonstrate that a simple heat sink model provides a good representation of the cooling data for the thermal distributions obtained.

Animals↗
PubMedDate not supplied

Heat loss and blood flow during hyperthermia in normal canine brain. II: Mathematical model.

A mathematical model for heating and cooling during hyperthermia has been developed from an appropriate solution of a bioheat transfer equation. Predicted cooling rates obtained from the model have been compared with cooling rates obtained from experiments performed on both perfused and non-perfused normal canine brain tissue. The agreement between the predicted and observed cooling rates in non-perfused tissue is satisfactory (within 6-11 per cent) and provides confidence that the conduction process is being accurately represented. The model is then used to estimate the relative contribution of conductive and convective (blood flow) heat loss during cooling for the in vivo experiments. Estimates of blood flow dynamics are made from cooling data taken early and late in a heating course using the model to correct for conductive heat loss. Simplified forms of the bioheat transfer equation are examined. An adequate model for the observed cooling data is one that treats heat loss (both conduction and blood flow) as a heat sink (i.e. an effective perfusion model) rather than an effective thermal conductivity model.

Animals↗
PubMedDate not supplied

Correlation of thermal parameters with outcome in combined radiation therapy-hyperthermia trials.

Many studies utilizing combined hyperthermia (HT) and radiation therapy (XRT) in the treatment of advanced or recurrent malignancies have reported a correlation between some measure of the minimum temperature achieved and outcome. Previous reported studies at Stanford have demonstrated a statistically significant correlation between the duration of local control and Tmin, the mean over treatments of the minima of (a) measured intratumoral temperatures in fields which contained diffuse or nodular tumours, or (b) measured interstitial temperatures in fields treated for microscopic residual disease. Recently, T90, the mean of the temperatures above which 90% of all measured intratumoral temperatures fall, has been proposed as an alternative characterization of the efficacy of the HT treatment that reportedly has a superior correlation with outcome. To test this hypothesis, T90 was computed by two different methods for three groups of patients treated at Stanford with XRT-HT for superficially located tumor recurrences. Tmin was found to be strongly correlated with T90 calculated by both methods. All three thermal parameters correlated with complete response at 3 weeks and with local control, although Tmin usually demonstrated the strongest correlation.

Adenocarcinoma↗