Raya S. Brown

Expression of hexokinase II and Glut-1 in untreated human breast cancer

Expressions of HKII and Glut-1 were studied in untreated primary human breast cancers by immunohistochemistry. 79% of the breast cancers were HKII-positive and 61% were Glut-1-positive. Average positive malignant cell areas were 66 +/- 41% for HKII and 29 +/- 36% for Glut-1. HKII staining was cytoplasmic, suggesting mitochondrial localization with no variations in staining intensities. Glut-1 staining was heterogeneous, cytoplasmic and membranous and varied with histology and tumor stage. Cells expressing HKII did not always express Glut-1 and vice versa. Increased FDG-uptake appeared to be associated with increased Glut-1 expression (P = 0.021), but not with HKII expression (p = 0.6).FDG uptake in breast cancer tissue appears to be associated with the extent of immunodetectable expression of Glut-1, but not that of HKII, and FDG uptake may differ between individual tumors depending on tumor stage and histology.

Intratumoral microdistribution of [131I]MB-1 in patients with B-cell lymphoma following radioimmunotherapy

Intratumoral microdistribution of radiolabeled anti-CD37 murine monoclonal antibody, [131I]MB-1, in lymph nodes from five patients with non-Hodgkins B-cell lymphoma following radioimmunotherapy were evaluated by microautoradiography and image analysis of macroautoradiographs. Microdistribution of radioactivity was highly heterogeneous: silver grain counts varied from 28-70 to 8-10 per 400 X field, and the coefficients of variations calculated by image analysis ranged between 42.5 and 79.3%. Variable radiation doses delivered could have contributed to the limited durability of tumor regression.

Autoradiography-based, Three-dimensional Calculation of Dose Rate for Murine, Human-tumor Xenografts

A Fast Fourier Transform method for calculating the three-dimensional dose rate distribution for murine, human-tumor xenografts is outlined. The required input includes evenly-spaced activity slices which span the tumor. Numerical values in these slices are determined by quantitative 125I autoradiography. For the absorbed dose-rate calculation, we assume the activity from both 131I- and 90Y-labeled radiopharmaceuticals would be distributed as is measured with the 125I label. Two example cases are presented: an ovarian-carcinoma xenograft with an IgG 2ak monoclonal antibody and a neuroblastoma xenograft with meta-iodobenzylguanidine (MIBG). Considering all the volume elements in a tumor, we show, by comparison of histograms and also relative standard deviations, that the measured 125I activity and the calculated 131I dose-rate distributions, are similarly non-uniform and that they are more non-uniform than the calculated 90Y dose-rate distribution. However, the maximum-to-minimum ratio, another measure of non-uniformity, decreases by roughly an order of magnitude from one distribution to the next in the order given above.

Quantitative autoradiographic evaluation of the influence of protein dose on monoclonal antibody distribution in human ovarian adenocarcinoma xenografts

SummaryWe studied the effect of monoclonal antibody protein dose on the uniformity of radioiodinated antibody distribution within tumor masses using quantitative autoradiography. Groups (n = 11–13/group) of athymic nude mice with subcutaneous HTB77 human ovarian carcinoma xenografts were injected intraperitoneally with an125I-labeled anticarcinoma-associated antigen murine monoclonal antibody, 5G6.4, using a high or a low protein dose (500 µg or 5 µg). At 6 days post-injection the macroscopic and microscopic intratumoral biodistribution of radiolabeled antibody was determined. The degree of heterogeneity of the labeled antibody distribution within each tumor was quantified and expressed as thecoefficient of variation (CV) of the activity levels in serial histological sections. Tumors from mice given the 500-µg protein doses had substantially lower CV values, 0.327±0.027, than did tumors from animals given 5-µg protein doses, 0.458±0.041, (P = 0.0078), indicating that the higher protein dose resulted in more homogeneous distribution of radioactivity in tumors than did the lower dose. While the percentage of the injected dose reaching the tumor was comparable between groups, injecting the higher dose of protein resulted in significantly lower tumor to non-tumor uptake ratios than those obtained for the lower protein dose. These data indicate, in this system, that to achieve more uniform intratumoral antibody (and radiation for radioimmunotherapy) delivery, a relatively high protein dose must be administered. However, to obtain this increased uniformity, a substantial drop in tumor/background uptake ratios was seen. Quantitative autoradiographic evaluation of human tumor xenografts is a useful method to assess the intratumoral distribution of antibodies.

Investigations into the route of uptake and pharmacokinetics of intraperitoneally-administered monoclonal antibodies: I. Transdiaphragmatic blockade of the terminal lymphatics in the rat

SummaryRecent studies on the intraperitoneal administration of radiolabeled monoclonal antibodies indicate that the diaphragm and, in particular, the lymphatics associated with the diaphragm are more involved in the transport of such high-molecular-mass moieties than was earlier suspected. The current study examines the role of the diaphragm in the i.p. transport of an IgG2a murine monoclonal antibody, 5G6.4, by observing the effect on the absorption of the antibody produced when the diaphragm has been scarred. Normal, sham-operated, and diaphragmatically scarred (abrasions made with 600-grade sandpaper) female Sprague Dawley rats (150–250 g) were administered intraperitoneal injections of125labeled 5G6.4 in a volume of 2.0 cm3. Approximately 5 µg antibody protein was administered in the individual 19-µCi injections per rat. Scarring was effective in partially blocking the amount of labeled antibody that crossed the diaphragm. Mean diaphragm levels (% injected dose/g) of125I-labeled 5G6.4 from the scarred group were 16.8% lower than values from the sham-operated rats and 37.2% lower than those from the control rats. The blockade was effective in slowing the appearance of the labeled antibody in the systemic circulation. The half-time to absorption was significantly prolonged in the scarred group; meant1/2 absorption values of 2.5 h for the control group, 5.3 h for the shamoperated group, and 9.6 h for the diaphragmatically blocked group were recorded. Scarring the diaphragm reduced the mean maximum blood concentration by 27.6% over the control group and 23.9% over the sham-operated group. The mean time to maximum blood concentration was lengthened by 93.0% over the control group and 35.3% over the sham-operated group due as a result of scarification. Presumably this impedence to absorption would increase the time that the radiolabeled antibody bathed the peritoneal space. The scarred group also had the largest “system mean residence time” (162.5 h) compared to the sham-operated (147.9 h) and control (118.7 h) groups. These values further verify the effect of surgery on the kinetics of the i.p. administered radiolabeled monoclonals. This work demonstrates that scarifying the diaphragm does alter the kinetics of the i.p. administered monoclonal antibodies and supports the concept that transdiaphragmatic lymphatic absorption is an important route of antibody clearance from the peritoneal cavity.

Immunolymphoscintigraphy in Breast Cancer: Evaluation Using 131I-Labeled Monoclonal Antibody B72.3

Noninvasive axillary lymph node staging was investigated using [131I]murine monoclonal antibody B72.3 in 16 patients with breast cancer scheduled for axillary dissection. [131I]B72.3 was injected into ipsilateral finger webs or around the breast biopsy. Scintigraphy to 72 h and gamma-counting/immunohistochemistry of nodes were performed. Specific antibody uptake (%ID/g) and the ratio of specific:nonspecific antibody uptake were not significantly different in tumor-positive versus tumor-negative nodes, suggesting that [131I]B72.3 is unsuitable to discriminate axillary node tumor involvement.

Effect of retinoids on the morphology of epidermal differentiationin vitro

Keratinocytes grown in submerged tissue culture progress from a single cell layer to more than ten layers while going through a series of alterations similar to differentiation in the intact epidermis. Many of the cytologlcal features of the different epidermal cell types are retained in these stratifying cultures. Vitamin A has an important influence on epithelial differentiation. The amount of Vitamin l and its analogs (retinolds) avallable to keratlnocytes will determine the degree of keratinlzatlon achieved during differentiation. Vitamin A deficiency can result in hyperkeratinlzation and squamous metaplasia. Excess of Vitamin A can result in mucuse metaplasla. The aim of this investigation is to study the effect of Vitamin A on the morphology of differentiating keratlnocytes in vitro.