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Biomedical subjects

R E Moran

Publications and source records attributed to R E Moran.

26 records · Page 2Linked to original sources

A method for establishing prolonged intravenous infusions in mice.

A simple and rapid method for establishing prolonged intravenous infusions in mice was developed. The major advantages of this system were ease of establishing infusions, ability to infuse large numbers of mice simultaneously, low incidence or perivenous infiltration, and little apparent stress to the mouse.

Animals↗

Dose-dependent cytokinetic changes following 1-beta-D-arabinofuranosylcytosine and hydroxyurea in L1210 and S-180 in vivo.

DNA synthesis inhibition and recovery in L1210 and S-180 ascites tumors following 1-beta-D-arabinofuranosylcytosine (Ara-C) and hydroxyurea (HU) were measured autoradiographically as a basis for optimizing drug schedules. Tumor bearing mice, 10(6) cells day 0, were treated on day 4 with 20, 200 or 2000 mg/kg Ara-C or 50, 300 or 1800 mg/kg HU. At various intervals following drug, [3H]thymidine was administered i.p. and mice were killed 1 hr later. Tumor cells were analyzed for labeling index (LI) and grain count (GC) to determine the percentage of cells in S phase and the distribution of DNA synthesis rates among the labeled cells, respectively. Following each dose of HU, DNA synthesis was inhibited completely. Recovery of LI was rapid and approached control values by 6 hr. Following each dose of Ara-C, DNA synthesis was inhibited completely for at least 6 hr. Recovery of LI was first noted 6 hr following 20 mg/kg Ara-C and 9 hr following 200 mg/kg. Following both doses the LI reached 100% of the control value by 26 hr. GC analysis indicated that following Ara-C treatment, DNA synthesis was reinitiated first with cells with low GC from 6 to 12 hr followed by cells with increasing GC from 12 to 20 hr. The labeling intensity reached control values by 20 hr and an 'overshoot' occurred by 26 hr. These data suggest that the recovery of DNA synthesis rate is a gradual process. Survival data for mice receiving two doses of Ara-C indicated that the optimal interval for retreatment following the lower dose of Ara-C occurred by 6 hr as compared to 12--16 hr for the higher dose. These times coincided in both instances with recovery of LI to 33--50% of control values. Early recovery of LI may be the best method currently available for estimating the optimal time for retreatment with an S phase specific drug.

Animals↗

US-guided core needle biopsy of the breast: technique and pitfalls.

When core needle biopsy of the breast is performed with ultrasound (US) guidance, the curvature of the breast is used to advantage. The breast is entered from the periphery; this approach allows one to avoid chest wall injury and improves needle visualization. Bringing the needle to the lesion by using a sweeping motion while keeping the transducer position relatively fixed will expedite the biopsy. Standard techniques are modified for evaluation of difficult lesions. Mobile lesions can be fixed with the palm of the operator's hand. Deep lesions can be lifted away from the chest wall with the tip of the needle. For lesions in large breasts, a steeper angle of approach may be necessary but can be matched with the transducer to improve needle visualization. Careful correlation with the mammogram will ensure that the corresponding sonographic abnormality is sampled. Although complications are uncommon, hematoma or infection may occur after the procedure. With practice, application of standard and modified techniques can result in efficient and accurate US-guided core needle biopsy of the breast.

Adult↗