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J W Hand

Publications and source records attributed to J W Hand.

8 recordsLinked to original sources
PubMed1979

Effects of hyperthermia on the mouse testis and its response to X-rays, as assayed by weight loss.

The effects of both hyperthermia alone and X-rays combined with hyperthermia on mouse testis have been investigated. Testis weight on heating time was observed for temperatures in the range 39.5 to 43.75 degrees C. The relationship between the reaction rate and the reciprocal of absolute temperature indicated that, over the temperature range considered, the activation energy associated with such thermal damage was (646 +/- 45) x 10(3) J mol-1. No evidence was obtained to indicate a change in slope of the Arrhenius plot over this temperature range. Finally, despite the high sensitivity of the testis to heat and X-rays, no thermal enhancement of the weight loss after irradiation was observed when thermal treatments which, if given alone would produce some observable damage, were administered immediately after irradiation.

Animals↗
PubMed1979

A microwave heating system for improving temperature uniformity in heated tissue.

A microwave heating system, designed to improve temperature uniformity in heated tissue, is described. The system employs parallel-opposed waveguide applicators, operating in the TE10 mode at 2450 MHz with the tissue to be heated (i.e. mouse intestine) immersed in a liquid which is both biologically compatible with and dielectrically similar to the tissue. The liquid improves the microwave coupling and avoids shape and size dependent absorption characteristics of the irregularly shaped tissue. Also, by maintaining this liquid at a suitable temperature with respect to that required in the tissue, the thermal losses and hence temperature gradients in the tissue are reduced compared with heating in hot liquid alone.

Animals↗
PubMed1979

The influence of blood flow on temperature distribution in the exteriorized mouse intestine during treatment by hyperthermia.

The non-uniform effects of hyperthermia observed in mouse intestine when heating is achieved by immersion of an exteriorized loop of jejunum in a hot bath were quantified. Intestinal damage was assayed by crypt destruction and correlated with local temperature and distance from major mesenteric blood vessels. The rate of rise of temperature during heating was much greater in regions far from blood vessels than in those close to vessels. Equilibrium temperatures in regions close to vessels were as much as 2 degrees C below liquid bath temperature. Such temperature differentials agreed well with those predicted from the heterogeneity observed in crypt destruction. Both histological and thermometric data suggest that major blood vessels may influence tissue temperature over a distance of approximately 2 mm and, within this region, temperature gradients of 1 degree C per mm may exist. These findings raise questions concerning the interpretation of previously reported data from water-bath heating of both tumours and normal tissues. They also emphasize the need for consideration of the influence of blood flow on heating patterns during hyperthermal treatment of patients.

Animals↗
PubMedDate not supplied

Early experience of a commercial scanned focused ultrasound hyperthermia system.

Preliminary experiences of the Sonotherm 6500 scanned focused ultrasound (SFUS) system in the hyperthermic treatment of bulky tumours in breast, superficial sites and within the pelvis in 22 patients are reported. Tumour volumes ranged from 235 to 603 cm3 (breast), 105 to 209 cm3 (superficial sites) and 24 to 905 cm3 (pelvis). Temperature distributions in 58 evaluable treatments were analysed in terms of temporal peak and time-averaged temperatures (highest and lowest temperatures, percentage of sensors exceeding index temperatures, etc.) achieved within scanned volumes. Mean number of sensors implanted into tumour was 14 in breast and superficial tumours and approximately 11 in pelvic tumours. Mean time-averaged maximum and minimum temperatures for the best treatments (i.e. for each patient, that with the highest percentage of sensors recording time averaged temperatures greater than or equal to 42 degrees C) administered to patients with tumours in the breast and superficial sites were 44.6 +/- 1.7 degrees C and 39.7 +/- 1.1 degrees C, respectively and the mean number of sensors exceeding 42 degrees C was 58 +/- 19%. In the case of pelvic tumours these figures were 41.6 +/- 0.9 degrees C, 40.0 +/- 0.6 degrees C and 8 +/- 12%, respectively. Patient tolerance to treatments was, in general, good. Areas where technical improvement of the system is appropriate and further research and development are required are identified; these should lead to a better realization of the potential of the SFUS technique, particularly for pelvic tumours.

Breast Neoplasms↗