Incorporation of 5-bromo-2'-deoxyuridine into colorectal liver metastases and liver in patients receiving a 7-day hepatic arterial infusion

Preclinical and clinical data suggest that the combination of hepatic arterial bromodeoxyuridine (BrdUrd), a thymidine analogue radiation sensitizer, and high-dose three-dimensional conformal radiation therapy offer a high potential for improving the local control of intrahepatic cancers. A key step in the design of a successful protocol is to determine in patients the conditions for BrdUrd administration that would be expected to produce selective radiosensitization of the tumor. Therefore, we designed a clinical trial to assess BrdUrd incorporation into the DNA of hepatic colorectal metastases and normal liver after a 7-day continuous BrdUrd infusion at a dose rate of 25 mg/kg/day (the maximal tolerated dose for a 14-day infusion) for patients undergoing laparotomy for either resection of liver metastases or hepatic arterial catheter and pump placement. Thirteen patients were entered into this study. We found that the average replacement of thymidine by BrdUrd in the tumor and normal liver were 11.6 +/- 1.2% and 1.1 +/- 0.2%, respectively. This extent of incorporation would be expected to produce a single fraction radiation enhancement of 1.5 in the tumor without detectable sensitization of the normal liver. Immunohistochemical staining for BrdUrd revealed heterogeneity of incorporation with a range of approximately 60-80% of the cells labeled in different regions of the specimens. These findings suggest that hepatic arterial BrdUrd given at this dose and schedule has a high likelihood of producing clinically significant radiosensitization for patients with hepatic metastases from colorectal cancer. Furthermore, the demonstrated selectivity of tumor perfusion that can be obtained with hepatic arterial infusion combined with the high proliferative rate of colorectal metastases (versus normal liver) suggests that these patients may be good candidates for tumor-directed gene transfer therapy by using regionally delivered retroviral vectors.

Studies with bromodeoxyuridine in head and neck cancer and accelerated radiotherapy

Using bromodeoxyuridine (BrdUrd), tumour cell proliferation was assessed, by flow cytometric (FCM) and immunohistochemical methods, in patients treated by the CHART regime of radiotherapy. Of 115 cases studied, data were complete in 90 using both methods. No cell kinetic-related parameter predicted the outcome of patients treated by CHART, in keeping with the view that, with this regime, cellular proliferation had been minimised as a cause of failure. Histological evaluation of the labelling index (LI) revealed a trend for higher LI is in diploid tumours (16.2%) than in aneuploid (13.8%), contrasting to that found by FCM (5.0 and 9.3% respectively). When the Tpot was calculated using a combination of histology LI and FCM TS, diploid tumours showed more rapid proliferation (Tpot 1.8 days) than aneuploid tumours (Tpot 3.2 days); this finding was significant (p < 0.02). A novel parameter, termed proliferation pattern, unique to these studies with BrdUrd in vivo, was assessed. Both proliferation pattern and histological grading had predictive power to discriminate the outcome in univariate analysis (p = < 0.031 and 0.037, respectively). In a Cox multivariate analysis, proliferation pattern was the more important predictor. The studies reported highlight the extra information that can be gained from combining immunohistochemistry with flow cytometry to study the cellular proliferation of human tumours.

Efficacy of four antiviral agents in the treatment of uncomplicated herpetic keratitis

OBJECTIVE

To evaluate the efficacy of four antiviral agents--1% idoxuridine ointment (group 1), 2% trifluorothymidine ointment (group 2), 3% acyclovir ointment (group 3) and 1% bromovinyldeoxyuridine (BVDU) ointment (group 4)--in herpes simplex keratitis.

DESIGN

Randomized double-blinded clinical trial.

SETTING

Tertiary care institution in New Delhi.

PATIENTS

Eighty patients with uncomplicated herpes simplex keratitis of recent onset who had not previously received antiviral treatment.

MAIN OUTCOME MEASURES

Cure rate, frequency and severity of side effects.

RESULTS

Cure rates of 60%, 90%, 90% and 95% were obtained in groups 1, 2, 3 and 4 respectively. The average healing time was 13.4, 8.9, 8.5 and 7.5 days respectively. Side effects (follicular conjunctivitis, epithelial keratopathy and stinging) were more frequent in group 1 than in the other groups.

CONCLUSIONS

BVDU has a more pronounced therapeutic effect than idoxuridine, trifluorothymidine and acyclovir in uncomplicated epithelial herpetic disease of recent onset that has not previously been treated.

Bromodeoxyuridine immunohistochemistry of epon-embedded undecalcified bone in a canine fracture healing model

We evaluated bromodeoxyuridine (BrdU) immunohistochemistry of paraffin-, methyl methacrylate (MMA)-, and epon-araldite (epon)-embedded canine bone specimens to establish an optimal technique for studying cell kinetics of fracture healing in a canine tibial gap model. Dogs were sacrificed 4 months after tibial ostectomy and 1 hr after i.v. injection of BrdU (100 mg/kg). BrdU immunohistochemical staining with a peroxidase-labeled streptavidin-biotin (LAB-SA) method was performed on thin sections of tibia fixed in 70% ethanol and embedded in paraffin, MMA, or epon. Thin section of small intestines fixed in 70% ethanol and 10% neutral buffered formalin and embedded in paraffin, MMA, or epon were BrdU-stained and served as a model for proliferating tissue. Good and consistent BrdU immunostaining without detachment of bone sections was obtained for epon-embedded undecalcified bone sections. BrdU-positive cells were easily identifiable, in contrast to negligible background staining. BrdU-labeled osteoprogenitor cells and osteoblasts were observed around and on the surface of woven bone in external and internal callus of the ostectomy gap. Nuclei of osteocytes were not labeled. In contrast to the epon-embedded specimens, BrdU immunostaining of paraffin-embedded decalcified and MMA-embedded undecalcified bone specimens was unsatisfactory. The results of this study suggest that BrdU immunohistochemistry of ethanol-fixed, epon-embedded, undecalcified canine bone sections is a technique suitable for study of fracture healing with the described methodology.

Effect of aging and interval between primary and secondary treatment in carcinogenesis induced by neonatal exposure to 5-bromodeoxyuridine and subsequent administration of N-nitrosomethylurea in rats

LIO rats were exposed to s.c. injections (3.2 mg) of a synthetic analogue of thymidine, 5-bromo-2'-deoxyuridine (BrdUrd) on the 1st, 3rd, 7th and 21st days of life and at the age of 3 or 15 months they were i.v. injected with N-nitrosomethylurea (NMU) at a single dose of 10 or 50 mg/kg or with solvent. It was shown that early neonatal exposure to BrdUrd was followed by the increase in the incidence of tumor development and by the decrease of their latency. The carcinogenic effect of NMU alone correlated with the dose of the carcinogen in 3-month-old rats total and malignant tumors and tumors of some localization was decreased in the elder ones, but survival of tumor-bearing rats was decreased in the elder group as compared to the younger one. These data suggests the age-related decrease in both the carcinogenic effect of NMU and in the number of events which are necessary for a tumor development. The exposure to BrdUrd was followed by the increase in the susceptibility of rats to subsequent carcinogenic effect of NMU injected at the doses of 10 or 50 mg/kg into 3- and 15-month-old rats, mostly to the tissues being target to NMU. Our data have demonstrated that the exposure to BrdUrd in the early life was followed by the irreversible initiating effect which persists over a long time in a several tissues.

Radiation therapy and bromodeoxyuridine chemotherapy followed by procarbazine, lomustine, and vincristine for the treatment of anaplastic gliomas

PURPOSE

To conduct a Phase II study to evaluate the long-term efficacy and safety of radiotherapy combined with intravenous bromodeoxyuridine for patients with anaplastic glioma tumors.

METHODS AND MATERIALS

Between 1983 and 1987, study patients received 1.7-1.8 Gy radiation once a day, Monday through Friday, to a total dose of 60 Gy. On the Thursday prior to beginning radiotherapy and for the next 5 weeks (6 weeks total), patients received a continuous 96 h intravenous infusion of bromodeoxyuridine at 0.8 g/m2/24 h; following radiotherapy, patients received procarbazine, lomustine (CCNU), and vincristine (PCV) for 1 year or until tumor progressed.

RESULTS

One-hundred thirty eight patients (median age, 43 years) were evaluable for analysis. Estimated 4-year survival for the anaplastic astrocytoma (AA) stratum (n = 116) is 46%. For the astrocytoma (ASTRO) stratum (n = 22), the 6-year survival is estimated at 79%. Estimated 4-year progression-free survival for AAs is 42%, and for ASTROs, 68%. Whole brain irradiation was used in 23% and limited-field irradiation in 77%; patients receiving limited-field irradiation had a better survival rate (p = 0.07). Total tumor resection was performed in 15%, partial resection in 53%, and biopsy only in 32%. For the 81 patients with tumor recurrence, 34 (42%) are known to have received additional treatment(s). For AA, fits of the Cox proportional hazards regression model showed that covariates individually predictive of survival were younger age (p < 0.001), Karnofsky performance score (p = 0.10). Major toxicities were rash during Weeks 1 through 6 requiring dose modification in 14%, Grade > or = III leukopenia in 18%, and Grade > or = III thrombocytopeni in 9%.

CONCLUSION

The study suggests that the bromodeoxyuridine-radiotherapy-PCV, compared with other published therapies, can improve progression-free survival, and aggressive treatment of ASTRO patients can lead to substantial increases in survival compared to published survival data.

Pharmacokinetics and bioavailability of 5-ethyl-2'-deoxyuridine and its novel (5R,6R)-5-bromo-6-ethoxy-5,6-dihydro prodrugs in mice

The pharmacokinetics and oral (po) bioavailability of 5-ethyl-2'-deoxyuridine (EDU) and its novel 5,6-dihydro prodrugs (+)-trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy-5,6-dihydro-2'-deoxyuridine (BEEDU) and (+)-trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy-5,6-dihydro-5'-O-valeryl-2'- deoxyuridine (VBEEDU) were determined in male Balb/C mice following intravenous and no administration of a 0.4 mmol/kg dose. EDU was eliminated from blood with a half-life of 35.2 +/- 4.2 min. The mean residence time (MRT) and the area under the blood vs. time curve (AUC) for EDU after iv injection were 45.1 +/- 11.7 min and 1.7 +/- 0.2 mumol.g-1.min, respectively. EDU showed a 49% bioavailability in male.Balb/C mice. The pharmacokinetic parameters and bioavailability of EDU were improved significantly upon administration of the 5,6-dihydro prodrugs BEEDU or VBEEDU. The AUC of EDU after a 0.4 mmol/kg iv dose of BEEDU was 2.1 +/- 0.3 mumol.g-1.min, which is substantially higher than that after iv injection of EDU. The half-life and MRT of EDU were increased to 251.9 +/- 30.2 min and 352.0 +/- 91.5 min, respectively, after injection of BEEDU. The po bioavailability of EDU, after administration of BEEDU, was increased almost 2-fold (81%), compared with that of EDU (49%). The AUC of EDU after iv injection of VBEEDU was 1.8 +/- 0.2 mumol.g-1.min. The half-life and MRT of EDU, the active metabolite of VBEEDU, were 106.0 +/- 23.2 min and 157.0 +/- 40.8 min, which are substantially higher than those for EDU after administration of EDU.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo bromodeoxyuridine (BrdU)-labelling index of rat thymus: influence of different BrdU doses and exposure times as analyzed both in tissue sections and in single cell suspensions

Tissue sections and single cell suspensions of rat thymus were analyzed by flow and image cytometry to study the effects of different doses of bromodeoxyuridine (BrdU) (10, 50 and 100 mg/kg and different labelling periods (15, 30 and 60 min) on the BrdU-labelling index. The proportions of BrdU-labelled cells, as analyzed by flow cytometry, were similar in the different groups of our study. However, the quality of the results was not exactly the same, since when the BrdU dose decreased, the separation between BrdU-positive S-phase cells and both the G0/G1 and the G2/M BrdU-negative cells on a DNA/BrdU histogram became less clear. On the other hand, the proportion of BrdU-labelled cells in tissue sections was greater in the groups of animals that received doses of 100 mg/kg and were killed 15, 30 or 60 min later than in the sections obtained from the remaining groups. Our results show that both dose and exposure time to BrdU may influence the final results when cell proliferation is assessed, the variations obtained clearly depending on the technique used for the immunological detection of BrdU-positive S-phase cells.

Proliferative characteristics of head and neck tumors. In vivo evaluation by bromodeoxyuridine incorporation and flow cytometry

Cell proliferation of head and neck cancers was studied in 52 patients using in vivo bromodeoxyuridine (BUDR) incorporation. Patients received 250 mg BUDR intravenously several hours prior to biopsy of the tumor tissue. Bivariate flow cytometry was used and enabled us to rapidly obtain DNA ploidy, labelling index (LI), DNA synthesis time (TS) and tumor potential doubling time (Tpot). This method was found to be suitable to obtain complete cytokinetic data in 46/52 (88.5%) patients. The mean BUDR LI was 7.9% (range 2-18%); mean TS was 11.6 h (range 6-28.5 h); mean Tpot was 5.7 days (range 2-30 days). BUDR LI and TS were significantly correlated with histological differentiation grading: G3 tumors showed higher LI values and shorter TS values than G1/G2 tumors. A similar correlation was found between LI or TS and tumor dimensions. Tpot was also significantly lower in larger tumors, such as in those with a higher grading. No significant correlation was found between LI or TS and DNA ploidy (50% of the tumors in our series were DNA aneuploid), while Tpot was found to be 10 days in diploid tumors, compared to only 6.3 days for the aneuploid tumors (p < 0.05). All cases with documented lymph node involvement (N+) showed significantly higher LI, and shorter TS and Tpot values if related to nodal free ones (Tpot = 10 days in N+ patients and 6.3 days in N- patients; p < 0.05). The results of this study suggest that the method employed is clinically feasible and could be a useful aid in defining the prognosis of head and neck cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Increasing 1-beta-D-arabinofuranosylcytosine efficacy by scheduled dosing intervals based on direct measurements of bone marrow cell kinetics

The therapeutic efficacy of cell cycle phase-specific drugs can be improved by repeated administrations, the dosing interval being related to the cell cycle time of the susceptible normal host tissue. Kinetic measurements of bone marrow cell proliferation, with bromodeoxyuridine labeling and flow cytometry analysis, were used to determine the optimal dosing intervals of 1-beta-D-arabinofuranosylcytosine for minimizing bone marrow cell damage in mice. The results showed that cells surviving a single dose 1-beta-D-arabinofuranosylcytosine treatment remained temporarily blocked at the G1-S boundary, and upon release from the block the cells crossed through S phase in a nearly synchronized way. The optimal spacing of repeated treatments, evaluated by measurements of the drug-induced transit times through the different cell cycle phases, equaled the bone marrow cell cycle time following treatment. Repeated 1-beta-D-arabinofuranosylcytosine injections according to this protocol markedly diminished drug toxicity in C3H mice, as compared to protocols of other time intervals. A therapeutic schedule based on these measurements was highly effective in lymphoma-bearing mice: the designed protocol of dosing intervals significantly delayed tumor growth whereas other intervals were highly toxic.

Bromodeoxyuridine-mediated radiosensitization in human glioma: the effect of concentration, duration, and fluoropyrimidine modulation

PURPOSE

To define the relative influence of duration of exposure, concentration, and modulation by fluorodeoxyuridines (FdUrd) on the incorporation of 5-bromo-2-deoxyuridine (BrdUrd) into DNA of a human malignant glioma line (D-54) in vitro and in vivo.

MATERIALS AND METHODS

IN VITRO STUDIES

an established human malignant glioma line (D-54) was exposed to a clinically achievable concentration of BrdUrd to model intravenous (1 microM BrdUrd) and intraarterial (4 microM BrdUrd) conditions. The influence of modulation was assessed using 1 nM FdUrd. Incorporation of BrdUrd, radiosensitization, and cytotoxicity were determined after 24, 72, and 120 h drug exposures. In Vivo studies: nude mice bearing D-54 xenografts were infused with BrdUrd at 100 mg/kg/day for 7 and 14 days or BrdUrd at 400 mg/kg/day for 5 days. The influence of modulation was assessed by combining 100 mg/kg/day of BrdUrd with 0.1, 0.3, and 1 mg/kg/day FdUrd for 7 days. Incorporation of BrdUrd into the DNA of tumor, gut, and marrow were determined.

RESULTS

In Vitro: thymidine replacement and radiosensitization were a function of concentration, and incorporation began to plateau after 2 to 3 population doublings. Modulation with 1 nM FdUrd significantly increased incorporation. Radiosensitization was a linear function of thymidine replacement under all conditions tested. In Vivo: infusion with 400 mg/kg/day for 5 days resulted in greater tumor incorporation (10.3 +/- 0.4% thymidine replaced) than treatment with 100 mg/kg/day for 14 days (6.0 +/- 0.6% of thymidine replaced). Infusion of FdUrd with BrdUrd increased normal tissue incorporation of BrdUrd, but failed to increase BrdUrd incorporation in tumor cells.

CONCLUSION

These results suggest that relatively short, high dose rate infusions may be preferable to long, low dose rate infusions. The potential benefit of FdUrd modulation demonstrated in vitro may be difficult to realize using continuous systemic infusions.

Radiosensitization with carotid intra-arterial bromodeoxyuridine +/- 5-fluorouracil biomodulation for malignant gliomas

Bromodeoxyuridine (BUdR), a nonhypoxic radiosensitizing drug, is a halogenated pyrimidine analog that is incorporated into the DNA of dividing cells in a competitive process with thymidine. BUdR sensitizes cells to radiation therapy. 5-Fluorouracil (5-FU) inhibits the endogenous synthesis of thymidine, resulting in increased incorporation of the BUdR. Neurons and glial cells have a very low mitotic rate; they will not incorporate BUdR and will not be sensitized. BUdR and 5-FU are best delivered intra-arterially (IA) because of their regional advantage. We infused BUdR +/- 5-FU over 8 1/2 weeks, before and during 59.4-Gy focal conformal external beam radiation therapy, through a permanently implanted pump with a catheter placed retrograde through the external carotid artery to the carotid bifurcation. Sixty-two patients with grades III or IV glioma were entered into one of two trials, with 23 patients receiving BUdR alone and 39 patients receiving BUdR + 5-FU. The maximum tolerated dose (MTD) of BUdR alone was 400 mg/m2/d for 8 1/2 weeks. The Kaplan-Meier median survival (KMS) was 20 months. In the BUdR + 5-FU trial, the MTD of BUdR was also 400 mg/m2/d and 5-FU was 5 mg/m2/d with a KMS of 17 months. The KMS of all 62 patients in both trials 1 and 2 was 18 months. Pathologic grading used both the original World Health Organization (WHO) and 1993 modified WHO systems. The KMS of grade IV patients was 13.8 months (48 patients) with the original system and 17 months (58 patients) with the modified system.(ABSTRACT TRUNCATED AT 250 WORDS)

[An experimental study on radiotherapy for esophageal cancer using intraluminal administration of radiosensitizer]

This study was undertaken to evaluate the efficacy of intraluminal administration of 5-bromo-2'-deoxyuridine (BUdR) as a radiosensitizer during radiotherapy for esophageal cancer. Lipid-surfactant mixed micelles (MM) was used as an absorption promoter. VX2 carcinoma cells were endoscopically injected into the esophageal wall of rabbits. Two weeks after tumor inoculation, BUdR (100 mg/body) with MM was administered into the esophageal lumen and kept for 3 hours. Subsequently, animals were irradiated with 60Co at dosages of either 5 or 10 Gy. Twelve days after, animals were sacrificed to determine tumor diameter and to evaluate histological effect of radiation. BUdR uptake rates of tumor tissue were determined two weeks after tumor inoculation. Tumor diameters in control animals and those treated with simple irradiation at a dose of 5 Gy were similar. In contrast, irradiation at a dose of 5 Gy significantly reduced tumor diameters when combined with intraluminal administration of BUdR with MM. In cancer bearing animals receiving irradiation under intraluminal injection of BUdR with MM, the histological effect were apparently enhanced as compared to animals receiving simple irradiation. BUdR uptake rates of primary tumors showed a significant increase in animals with the intraluminal administration of the drug as compared the those with intravenous one shot bolus and intravenous drip infusion. Based on those results, we conclude that preoperative radiotherapy combined with intraluminal administration of radiosensitizer could be an effective method.

Keratinocyte growth factor induces pancreatic ductal epithelial proliferation

Keratinocyte growth factor (KGF) causes a proliferation of pancreatic ductal epithelial cells in adult rats after daily systemic administration for 1 to 2 weeks. Even before the proliferation of intralobular ducts is histologically evident, KGF also induces proliferating cell nuclear antigen expression within the ductal epithelium of intercalated, intralobular, and interlobular ducts. KGF also causes incorporation of 5-bromodeoxyuridine in ductal epithelial cells. Epithelial cell proliferation is histologically most prominent at the level of the intralobular ducts adjacent to and within the islets of Langerhans. Pancreatic ductal proliferation is not histologically apparent in rats sacrificed 7 to 10 days after the cessation of KGF administration. The pancreatic hormones insulin, glucagon, somatostatin, and pancreatic polypeptide are normally distributed within islets that demonstrate intrainsular ductal proliferation. The proliferating ductal epithelium does not show endocrine differentiation as evidenced by the lack of immunoreactivity for pancreatic hormones. KGF is a potent in vivo mitogen for pancreatic ductal epithelial cells.

Clinical pharmacology of hepatic arterial infusions of 5-bromo-2'-deoxyuridine

This investigation was undertaken to determine the pharmacokinetic parameters relevant to hepatic arterial (HA) infusion of 5-bromo-2'-deoxyuridine (BrdUrd) and to ascertain the maximum tolerated dose and related toxicities of BrdUrd administered as a 14-day HA infusion. In the pharmacokinetic study, 6 patients received a 2-h i.v. infusion (to steady-state) of BrdUrd at each of 5 escalating dose rates (10 to 160 mg/kg/day) with simultaneous blood sampling for BrdUrd levels from HA and hepatic venous catheters. Dose dependent HA and hepatic venous drug levels, total body clearance, hepatic extraction, and estimated regional exposure advantage were determined. The total body clearance of BrdUrd was high and dose rate dependent, falling from 3340 ml/min with a 10-mg/kg/day infusion to 2180 ml/min at a 160-mg/kg/day dose rate. Hepatic extraction was high and dose rate dependent as well, declining from 80% extraction at 10 mg/kg/day to 68% at 160 mg/kg/day. The calculated estimate for the exposure advantage achievable with HA as compared with i.v. infusion reflects the dose rate dependence of total body clearance and hepatic extraction and decreases from a 70-fold advantage at 10 mg/kg/day to a 30-fold advantage at 160 mg/kg/day. In the Phase I study aimed at determining the maximum tolerated dose, successive groups of 3 patients were administered continuous HA infusions for 14 days at escalated BrdUrd dose rates (5, 10, 15, 25, and 35 mg/kg/day) in order to ascertain dose-limiting toxicity. The maximum tolerated dose of BrdUrd for a 14-day continuous HA infusion was found to be 35 mg/kg/day with reversible thrombocytopenia as the sole dose-limiting toxicity. Skin and other toxicities were infrequent, minor, reversible, and non-dose dependent. No hepatic toxicity was detected despite direct drug infusion into the liver. The high total body clearance and hepatic extraction of BrdUrd substantiate its administration via the hepatic artery as a means to achieve higher exposure with intrahepatic tumors than can be obtained by systemic administration. Despite higher hepatic exposures, no hepatic toxicity was noted, and readily reversible systemic toxicity (thrombocytopenia) was dose limiting for the 14-day continuous HA infusion. Thus, HA infusion of the potent radiosensitizer BrdUrd is both pharmacokinetically rational and well tolerated.

Preparation, characterization and release of microencapsulated bromodeoxyuridine

Biodegradable and biocompatible microspheres with bromodeoxyuridine (BrUrd) have been prepared, characterized and tested in vitro and in vivo. Scanning electron microscopy and image analysis revealed regular spherical shapes and an average size +/- SD of 2.47 +/- 0.59 microns. Total content of BrUrd as determined by HPLC was within the range of 0.2-1.5%. Kinetic analyses of two different preparations showed similar release half-times (approx. 12 hrs), kinetic constants -0.0556, -0.0564, and -0.0557, -0.0597 [h-1], and correlation coefficients of 0.998, and 0.999 when fitted to the first order or biphasic first order kinetics, respectively. Preliminary data from immunocytochemical studies revealed efficient incorporation of BrUrd delivered from these microcapsules into nuclei of proliferating cells surrounding brain lesions in rats.

Kinetics of mammary epithelial cell proliferation in pituitary isografted BALB/c mice

Recently, we have published that treatment of pituitary isografted BALB/c mice with a single injection of N-methyl-N-nitrosourea (MNU) leads to the rapid development of mammary tumors in over 90% of the animals (Guzman et al., Cancer Res., 52, 5732-5737). In the present study, we characterized the changes in proliferative activity and lobulo-alveolar differentiation of MECs at different time intervals after isografting animals with pituitary glands. Virgin BALB/c mice 1, 3, 5 or 8 weeks after pituitary isografting were either pulse-labeled for 2 h or continuously infused with bromodeoxyuridine (BrdU) and the percentage of BrdU-labeled MECs was assessed. The S-phase duration (TS) of MECs was evaluated by double labeling with [3H]thymidine and BrdU. The population potential doubling time (TP) was calculated from the values of BrdU-LI and TS. Three stages of proliferation and differentiation of MECs in pituitary isografted virgin BALB/c mice were observed: (i) A sharp increase in the percentage of proliferating MECs of the terminal ducts and ductal branchings in the first 1-2 weeks, (ii) Development of lobulo-alveolar structures from the terminal ductal and alveolar buds, between weeks 3 and 5 with the highest BrdU-LI in week 3 and (iii) Multiplication of the alveolar structures and decrease in the BrdU-LI between weeks 5 and 8. The BrdU-LIs of alveolar cells 5 weeks after isografting the animals were significantly higher than those of the ductal cells. The continuous administration of BrdU for 3, 5 or 7 days by using osmotic pumps revealed zones in the ducts where almost all MECs were labeled as well as zones lacking proliferate activity. When the BrdU administration was extended for 10-14 days, almost all (> 95%) ductal and lobular epithelial cells were labeled. A small percentage (< 5%), of ductal and lobulo-alveolar MECs cells, remained unlabeled even after 14 days infusion of BrdU. The TS and TP values were shorter in pituitary isografted animals than in controls, but no significant difference was found for either values between the ductal and alveolar cells in either isografted or control mice. Changes in proliferation kinetics of mouse MECs in pituitary isografted animals correlated with the circulating concentrations of prolactin, progesterone and 17 beta-estradiol, but not with corticosterone, growth hormone or thyroxin.(ABSTRACT TRUNCATED AT 400 WORDS)

Flow cytometric analysis of bromodeoxyuridine-induced micronuclei

The effects of DNA substitution by the thymidine analogue 5-bromodeoxyuridine (BrdU) on cell cycle progression and micronucleus induction were studied in different mammalian cell cultures. Simultaneous flow cytometric measurements of DNA content and side scatter of nuclei in Chinese hamster embryo (CHE) cells revealed a concentration-dependent temporary block in the G2/M phase of the first cell cycle. NIH 3T3 cells and human amniotic fluid fibroblast-like cells, on the contrary, did not show any cell cycle disturbances in the presence of BrdU. Micronucleus frequency increased as soon as CHE cells started to divide and reached a plateau when all cells have divided. The height of this plateau was almost equal for 60 and 100 microM BrdU. This saturation of micronucleus induction was due to a saturation of BrdU incorporation into DNA already at a doses of 60 microM as shown by the BrdU/Hoechst quenching technique. Indirect immunofluorescent staining of kinetochores with CREST antibodies revealed that nearly all BrdU-induced micronuclei were kinetochore-negative suggesting the presence of acentric chromosome fragments in these micronuclei. DNA distributions of micronuclei measured by flow cytometry showed several peaks representing micronuclei which contain DNA fragments of defined sizes induced by non-random breakage of chromosomes 1 and X as verified by flow karyotyping and C-banding.

Cell kinetic evaluation of human colonic aberrant crypts. (Colorectal Cancer Study Group of the University of Modena and the Health Care District 16, Modena, Italy)

Foci of aberrant crypts (ACF) have been observed on the unsectioned, methylene blue-stained mucosal surface of the human colon. Experimental evidence and the histological features of the lesions suggest that they might be early events in colon cancer development. The main objective of the present study was to evaluate cell kinetic properties of ACF in the human colon. Five samples of colon mucosa were collected immediately after operation following the administration of 500 mg of 5'-bromo-2'-deoxyuridine prior to surgery. ACF were then identified on the fixed, unsectioned, methylene blue-stained mucosal surface under a light microscope. Some specimens containing ACF were serially sectioned perpendicular to the luminal surface of the intestine, along with specimens of normal-appearing mucosa. Several sections were prepared for the immunohistochemical identification of 5'-bromo-2'-deoxyuridine-incorporating cells (in the S phase of the cell cycle). The results of this study demonstrated that aberrant crypts have more cells per crypt than normal glands. Total labeling index and labeling index values in each of the five longitudinal compartments in which each crypt was divided showed an increased total proliferative activity in all ACF examined, although limited to the lower crypt compartments in almost all aberrant crypts evaluated. These findings are in keeping with previous cell kinetic studies and observations in experimental animals and provide evidence of the involvement of human aberrant crypts in the stepwise process leading from normal mucosa to colon cancer.

Effect of cyclosporine on liver regeneration after orthotopic reduced-size hepatic transplantation in the rat

These experiments were undertaken to study the effects of cyclosporine A (CsA) on liver regeneration after an isogeneic orthotopic reduced-size hepatic transplantation (RSHT) in rats. Male Wistar rats were treated with or without a daily injection of CsA beginning 24 hr before surgery and were subjected to a 68% partial hepatectomy. A isogeneic orthotopic reduced-size hepatic transplantation was performed in recipient rats pretreated with or without CsA. A daily injection of CsA was continued until the recipient rats were sacrificed. Animals were sacrificed at various time points (12, 24, 36, 48, and 72 hr) postoperatively. The incorporation of bromodeoxyuridine (BrdU) into the DNA of the remnant hepatocytes was evaluated by immunohistochemical staining with a monoclonal antibody against BrdU. CsA (10 mg/kg/day) significantly augmented BrdU incorporation into hepatocytes after hepatectomy. The maximum labeling index (LI) was observed at 24 hr after hepatectomy. In contrast, the maximum LI in the recipient rats not receiving CsA was seen at 36 hr after RSHT, and 10 mg/kg/day of CsA decreased the LI at 36 hr after RSHT. A lower dose of CsA (3 mg/kg/day), however, significantly increased the LI in the recipient rats (P < 0.01), and it reached a peak at 24 hr after RSHT when compared to the transplant recipients not receiving CsA. The time course of the increase in the LI in the transplant recipient rats receiving 3 mg/kg/day of CsA was similar to that observed in the rats after hepatectomy. This dosage improved the delay in the reduced-size hepatic transplant LI reaching its peak.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a new lipophilic prodrug 3', 5'-dioctanoyl-5-bromodeoxyuridine (BrdU-C8) suspended in Lipiodol as a radiosensitizer for the treatment of AH136B tumor

The effect of anti-cancer treatment on the AH136B tumor was studied using external beam irradiation in combination with a new oil-soluble agent, 3', 5'-dioctanoyl-5-bromodeoxyuridine (BrdU-C8), a lipophilic prodrug of BrdU. BrdU-C8 was dissolved in an oily lymphographic agent, Lipiodol (BrdU-C8/Lipiodol). BrdU-C8/Lipiodol is selectively accumulated in the neovasculature of the tumor and gradually releases BrdU. The AH136B tumor cell, a transplantable rat ascites hepatoma cell line, was implanted in the dorsal foot of rats. In vivo labeling index (L.I.) of the tumor cells after the intraarterial infusion of BrdU-C8/Lipiodol was significantly increased compared to the L.I. observed after intraarterial or intravenous infusion of BrdU. In addition, X-ray irradiation in combination with intraarterial infusion of BrdU-C8/Lipiodol significantly inhibited the tumor growth, indicating the increased radiosensitizing effect.

Analysis of the results of combined therapy for maxillary carcinoma

BACKGROUND

Maxillary sinus carcinomas usually are locally advanced. A wide variety of modalities, including surgery, radiation therapy, and intraarterial chemotherapy, alone or in combination, have been used. However, there is still much controversy with regard to the optimum treatment.

METHODS

From 1972 to 1986, 108 patients with squamous cell carcinoma of the maxillary sinus were treated at the Department of Radiology, University of Tokyo Hospital. From 1972 to 1974 (the first period), the treatment consisted of operation for reduction of tumor volume, daily cleaning of the maxillary antrum, 20 Gy of postoperative radiation therapy, and intraarterial infusion of 1500 mg of 5-fluorouracil (5-FU) and 3000 mg of 5-bromodeoxyuridine (BUdR). From 1975 to 1979 (the second period), the radiation dose was reduced to 10 Gy, and intraarterial infusion of 5-FU and BUdR was not performed. Surgery for reduction of tumor volume and daily cleaning of the antrum played a major role in this period. From 1980 to 1982 (the third period), daily cleaning of the antrum was not performed. Instead, the dose of radiation was increased to 50-60 Gy. From 1983 to 1986 (the fourth period), more extensive surgery to resect the tumor en bloc was introduced. The radiation dose was increased to 70 Gy. Intraarterial infusion of 3750 mg of 5-FU and 120 mg of cisplatin also was administered.

RESULTS

The 5-year survival rate was 46% in the first period, 24% in the second period, 7.2% in the third period, and 53% in the fourth period. In the third period, there were more cases in which death resulted from a cause other than local failure, such as distant metastasis, pneumonia, or secondary primary cancer. Since 1984, we planned treatment with computed tomography (CT) and used the linear accelerator with a multileaf collimator to treat patients with an irregular field of irradiation. These have made it possible to administer radiation therapy in doses as high as 70 Gy without severe complications and improve the survival rate, especially for T4 disease.

CONCLUSIONS

Radiation plays an important role in sterilizing malignant cells that cannot be removed by operation. The dose of radiation should be determined according to the volume of residual tumor. Careful treatment planning is required to irradiate the tumor adequately and reduce complications.

Scanning electron microscopy of the centromeric region of L-cell chromosomes after treatment with Hoechst 33258 combined with 5-bromodeoxyuridine

When mouse L-cells were treated with a combination of 5-bromodeoxyuridine (BrdUrd) and Hoechst 33258, the metaphase chromosomes revealed under-condensation of the chromatin fibers in the sister centromeres. The application of the osmium-thiocarbohydrazide technique to the air-dried chromosome preparations made it possible to elucidate the ultrastructure of the under-condensed centromeric region at the level of the 30 nm chromatin fiber. Scanning electron microscopy revealed that the under-condensed region consisted of a coiled fiber with a diameter of about 400 nm, and a gyre diameter of approximately 600 nm. The coiled fiber was composed of the 30 nm chromatin fiber loops. These findings indicate that a continuous coiled structure, which is the final higher order structure of the condensed chromatin fiber, exists throughout the entire length of the mouse L-cell metaphase chromosome.

Blood supply and drug delivery to primary and secondary human liver cancers studied with in vivo bromodeoxyuridine labeling

BACKGROUND

Because bromodeoxyuridine (BrdU) is incorporated into DNA synthesizing (S-phase) cells, the blood supply of liver tumors can be traced by injecting BrdU into either the hepatic artery or portal vein. It also is possible to study the delivery of anti-cancer drugs acting during S-phase when they are injected by these routes. The blood supply of and drug delivery to liver tumors were examined using BrdU in patients with 19 metastatic liver cancers and 8 hepatocellular carcinomas.

METHODS

At the time of hepatic resection, 200 mg of BrdU was injected by the various routes or 200 mg of BrdU suspended in 2 ml of a lipid contrast medium was injected into the hepatic artery by a reported method 2 weeks before hepatectomy. The liver tumors resected were stained immunohistochemically with an avidin-biotin-peroxidase complex method using anti-BrdU monoclonal antibody.

RESULTS

BrdU injected into the hepatic artery or portal vein was incorporated into the metastatic liver tumor. After intraarterial infusion BrdU suspension, the delivery of BrdU was enhanced. The nuclei of hepatocellular carcinomas that received BrdU from the hepatic artery or portal vein incorporated BrdU.

CONCLUSIONS

Metastatic liver cancers had both arterial and portal blood supplies. Hepatocellular carcinomas also had, not only an arterial, but also a portal blood supply. In both primary and secondary hepatic cancers, the delivery of anti-cancer agents acting during S-phase using the lipid contrast medium administration method was excellent.