Biomedical subjects

L N Salling

Publications and source records attributed to L N Salling.

4 recordsLinked to original sources

PubMed1995

The effect of castration on tumor growth rate and cell kinetics in hormone sensitive and hormone insensitive rat prostatic adenocarcinomas.

Cell kinetics were measured in vivo in four experimental rat prostatic adenocarcinomas grown in normal or castrated rats. The aim was to investigate the effect of castration on growth rate and cell kinetics in hormone sensitive and hormone insensitive prostatic carcinomas. We used two anaplastic, hormone insensitive, fast growing tumors (Dunning R-3327-AT1 H and E), as well as two well differentiated, hormone sensitive, slow growing tumors (R-3327-H and R-3327-PAP). DNA ploidy, S-phase transit time (Ts), the labeling index (LI) and potential doubling time (Tpot) was determined by dual parameter flow cytometry, after in-vivo labeling, using bromodeoxyuridine (BUdR) and the tumor doubling time (DT) was determined from growth curves. After castration DT in the hormone sensitive H-subline changed from 21.7 days to 82.0 days, and in the PAP-subline from 22.2 days to 33.2 days. No significant changes in Tpot were observed. In the anaplastic tumors no differences in neither DT nor Tpot were seen. The cell loss factor (CLF) was relatively low in the two anaplastic tumors (0.55-0.59) compared to the well differentiated tumors. The CLF was unaffected by castration in the poorly differentiated tumors, whereas it increased significantly (from 0.75 to 0.92, P = 0.005) after castration in the H-tumor, and showed a non-significant increase in the PAP-tumor. This implies that the decrease in tumor growth in the hormone sensitive tumors is due to an increase in cell death, not a decrease in cell proliferation. These data indicate that CLF is the dominating factor in the reduced growth following androgen ablation in an androgen sensitive tumor. This study suggests that Tpot might be an additional predictor of a tumors proliferating rate and it may provide important information of the human prostatic cancer.

Adenocarcinoma↗

PubMed1994

Influence of sampling time on assessment of potential doubling time.

Potential doubling time (Tpot), S-phase transit time (Ts), and labeling index were determined in three experimental rodent tumors by in vivo incorporation of bromodeoxyuridine and flow cytometry. The kinetic parameters were derived from the relative movement method at varying sampling times (time between injection of bromodeoxyuridine and tumor excision). Ts and Tpot were close to the expected (extrapolated) values of the two parameters with sampling time within the range 60-100% of the expected Ts. With short sampling time, Ts and Tpot were considerably over- or underestimated. By use of the original method by (Begg et al., Cytometry 6:620-626, 1985), the Tpot came out with a twofold overestimation with a short sampling time. Generally, modified methods for calculation of Ts did not improve the results. When Tpot is measured in human tumors, there is no a priori knowledge of the kinetic parameters. Consequently, the sampling time must be based on the general experience of tumor cell kinetics in the specific tumor type measured. A relatively long sampling time should be aimed for when measuring Tpot in human tumors. With proper sampling time, Tpot assessed by flow cytometry was found to be a precise and reproducible parameter.

Adenocarcinoma↗

PubMed1994

Deep heating using a movable applicator phased array hyperthermia system. A preclinical feasibility study.

A preclinical evaluation of the 'movable applicator phased array hyperthermia system' was performed. The system employs four coherent applicators enabling power steering by amplitude and phase control. This concept has already been used in other systems, but the combination with a compact applicator design and easy movement of applicators has not been used before. The paper contains a description of the system and a verification of its performance using quality assurance tests with scanned E-field measurements. A clinical simulation was performed in pig to address the clinical feasibility of the system. The target volume was the left kidney. Two heating sessions, with and without occluded blood-flow to the kidney, were performed. In the low-flow experiments a temperature of 48 degrees C and 46 degrees C was obtained in the upper and lower pole of the kidney respectively. For the high-flow experiment the temperature in the upper pole was 48 degrees C.

Animals↗

PubMed1990

Long-term observation of the detrusor smooth muscle in rats. Its relationship to ovariectomy and estrogen treatment.

We studied the bladders of 24-month-old intact rats, rats that had been ovariectomized at the age of 6 months, and intact and ovariectomized rats treated by estrogen from the age of 16 months. The study thus comprized four groups: group I: bilaterally ovariectomized rats; group II: intact rats; group III: ovariectomized rats treated with estrogen; group IV: intact rats treated with estrogen. The weight and collagen concentration of the bladders were determined. The ovariectomized bladders weighed significantly less and had a higher collagen concentration than the intact bladders. Estrogen substitution for ovariectomized rats reversed these parameters. Detrusor strips were also used for organ bath studies. All bladders were similar in regard to the nerve-mediated frequency-response relationship. The atropine-resistant response was studied by adding scopolamine to the organ bath. Strips from ovariectomized rats had a significantly diminished atropine-resistant response, which was abolished by estrogen substitution. The present study suggests that micturition problems in menopause might have a structural as well as a pharmacological explanation.

Animals↗