Boron neutron capture therapy of intracerebral melanoma using boronophenylalanine as a capture agent.

A rat brain tumor model has been developed utilizing nude rats and the human melanoma cell line MRA 27. For pharmacokinetic and tissue distribution studies, 2 10(5) MRA 27 cells were implanted intracerebrally (i.c.), and 30 days later, 120 mg of 10B-enriched L-boronophenylalanine were injected i.p. into nude rats. 10B concentrations in the tumor, blood, and normal brain were 23.7, 9.4, and 8.4 micrograms/g, respectively, 6 h following administration. For therapy experiments, tumor bearing rats were irradiated at the Brookhaven Medical Research Reactor 30 days following implantation. The median survival time was 44 days for untreated rats, 76 days for those receiving a physical dose of 2.7 Gy, and 93 days for those receiving 3.6 Gy. Animals receiving both 10B-L-boronophenylalanine and physical doses of 1.8, 2.7, or 3.6 Gy (total tumor physical doses of 5.0, 7.5, or 10.1 Gy) had median survival times of 170, 182, and 262 days, respectively. Forty % of rats that received the highest tumor dose (10.1 Gy) survived > 300 days. In a replicate experiment 21% of animals that had received L-boronophenylalanine and irradiation (total tumor physical dose of 10.1 Gy) were alive 220 days after therapy. In a parallel study, animals that were irradiated with gamma photons from a 137Cs source with 12 Gy or 2.0 Gy 9 delivered to the head had median survival times of 86 and 79 days, respectively, compared to 47 days for untreated animals. Our results indicate that boron neutron capture therapy is effective against i.c. melanoma in a rodent model and suggest that large animal studies are warranted to further assess its efficacy.

Boron neutron capture therapy of brain tumors: enhanced survival following intracarotid injection of either sodium borocaptate or boronophenylalanine with or without blood-brain barrier disruption.

The purpose of the present study was to determine whether the efficacy of boron neutron capture therapy could be enhanced by means of intracarotid (i.c.) injection of sodium borocaptate (BSH) or boronophenylalanine (BPA) with or without blood-brain barrier disruption (BBB-D). For biodistribution studies, F98 glioma-bearing rats were injected i.v. or i.c. with either BSH (30 mg of boron/kg of body weight) or BPA (24 mg of boron/kg of body weight) with or without mannitol-induced, hyperosmotic BBB-D and killed 2.5 h later. The highest tumor boron concentrations for BSH and BPA were attained following i.c. injection with BBB-D (48.6 and 94.0 microg/g, respectively) compared to i.c. (30.8 and 42.7 microg/g) and i.v. injection (12.9 and 20.8 microg). Using the same doses of BSH and BPA, therapy experiments were initiated 14 days after intracerebral implantation of F98 glioma cells. Animals were irradiated 2.5 h after i.v. or i.c. administration of the capture agent with or without BBB-D using a collimated beam of thermal neutrons at the Brookhaven Medical Research Reactor. The median survival times of rats given BSH or BPA i.c. were 52 and 69 days, respectively, for rats with BBB-D; 39 and 48 days for rats without BBB-D; 33 and 37 days for i.v. injected rats; 29 days for irradiated controls; and 24 days for untreated controls. i.c. injection of either BSH or BPA resulted in highly significant enhancement (P = 0.01 and P = 0.0002, respectively) of survival times compared to i.v. injection, and this was further augmented by BBB-D (P = 0.02 and P = 0.04, respectively) compared to i.c. injection. Normal brain tissue tolerance studies were carried out with non-tumor-bearing rats, which were treated in the same way as tumor-bearing animals. One year after irradiation, the brains of these animals showed only minimal radiation-induced changes in the choroid plexus, but no differences were discernible between irradiated controls and those that had BBB-D followed by i.c. injection of either BSH or BPA. Our data clearly show that the route of administration, as well as BBB-D, can enhance the uptake of BSH and BPA, and, subsequently, the efficacy of boron neutron capture therapy.

Plasma atherogenic markers in congestive heart failure and posttransplant (heart) patients.

OBJECTIVES: We hypothesized that plasma factors important for the development of atherosclerosis play a major role in the occurrence of cardiac allograft vasculopathy (CAV). BACKGROUND: Cardiac allograft vasculopathy is a major cause of death among heart transplant recipients, has a poorly understood pathogenesis and has similarities to atherosclerotic coronary disease. METHODS: The study population consisted of 93 postcardiac transplant recipients. Thirty-one patients with congestive heart failure (CHF) and 18 healthy individuals served as control subjects. Posttransplant coronary anatomy was evaluated by angiography and intravascular ultrasound. Laboratory analyses of lipids, homocysteine, vitamin B12 and folate, fibrinogen, von Willebrand factor antigen (vWFAg) and renin were obtained on all participants. RESULTS: Posttransplant patients were found to have elevated serum triglycerides, total cholesterol/ high-density lipoprotein cholesterol ratio, lipoprotein (a), homocysteine, vWFAg, fibrinogen and renin and lower high-density lipoprotein cholesterol. Most of these laboratory atherogenic factors were also elevated to a similar degree in the CHF control population. Although most atherogenic markers were elevated, there was little correlation with CAV severity. Cardiac allograft vasculopathy severity varied with time after transplantation, 3-hydroxy-methyl-glutaryl-coenzyme A reductase inhibitor use and prior cytomegalovirus infection. Even within the normal range, lower RBC folate levels were associated with increased severity of CAV. CONCLUSIONS: The posttransplant course is associated with increased clinical and laboratory atherogenic factors, some of which likely contribute to the severity of coronary vasculopathy. Compared with normal control subjects, many of these markers are already increased in pretransplant CHF patients with or without occlusive coronary artery disease.

Depression as an antecedent to heart disease among women and men in the NHANES I study. National Health and Nutrition Examination Survey.

BACKGROUND: Depression predicts morbidity and mortality among individuals who have coronary heart disease (CHD), and there is increasing evidence that depression may also act as an antecedent to CHD. The studies that have reported a relationship between depression and CHD incidence or mortality either were restricted to men only or analyzed women and men together. The present investigation was conducted to evaluate the differential effect depression may have on CHD incidence and mortality in women and men. RESEARCH METHODS: We analyzed data from 5007 women and 2886 men enrolled in the first National Health and Nutrition Examination Survey (NHANES I) who were free of CHD at the 1982-1984 interview and who had completed the Center for Epidemiologic Studies Depression Scale (CES-D). Participants were evaluated from the 1982 interview date either until the end of the study (1992 interview date) or until the occurrence of a CHD event. Using CHD incidence and CHD mortality (International Classification of Disease, Ninth Revision, codes 410-414) as the outcome variables, Cox proportional hazards regression models were developed to evaluate the relative risk (RR) of CHD incidence and mortality in the depressed women and men separately, controlling for standard CHD risk factors. RESULTS: The women experienced 187 nonfatal and 137 fatal events, compared with 187 nonfatal and 129 fatal events among the men. The adjusted RR of CHD incidence among depressed women was 1.73 (95% confidence internal [CI], 1.11-2.68) compared with nondepressed women. Depression had no effect on CHD mortality in the women (RR, 0.74; 95% CI, 0.40-1.48). The adjusted RR of CHD incidence among depressed men was 1.71 (95% CI, 1.14-2.56) compared with nondepressed men. Depressed men also had an increased risk of CHD mortality compared with their nondepressed counterparts, with an adjusted RR of 2.34 (95% CI, 1.54-3.56). CONCLUSIONS: In this sample, while controlling for possible confounding factors, depression was associated with an increased risk of CHD incidence in both men and women, as well as CHD mortality in men. Depression had no effect on CHD mortality in women.

A nude rat model for neutron capture therapy of human intracerebral melanoma.

PURPOSE: The present study was carried out to determine the efficacy of Boron Neutron Capture Therapy (BNCT) for intracerebral melanoma using nude rats, the human melanoma cell line MRA 27, and boronophenylalanine as the capture agent. METHODS AND MATERIALS: Pharmacokinetic and tissue distribution studies: MRA 27 cells (2 x 10(5)) were implanted intracerebrally, and 30 days later, 120 mg of 10B-L-BPA were injected intraperitoneally into nude rats. Therapy experiments: Thirty days following implantation, tumor bearing rats were irradiated at the Brookhaven Medical Research Reactor. RESULTS: Pharmacokinetic experiments: Six hours following administration of BPA, tumor, blood, and normal brain boron-10 levels were 23.7, 9.4, and 8.4 micrograms/g respectively. Therapy experiments: Median survival time of untreated rats was 44 days compared to 76 days and 93 days for those receiving physical doses of 2.73 Gy and 3.64 Gy, respectively. Rats that had received both 10B-BPA and physical doses of 1.82, 2.73, or 3.64 Gy had median survival times of 170, 182, and 262 days, respectively. Forty percent of rats that had received the highest tumor dose (10.1 Gy) survived for > 300 days and in a replicate experiment 21% of the rats were longterm survivors (> 220 days). Animals that received 12 Gy in a single dose or 18 Gy fractionated (2 Gy x 9) of gamma photons from a 137Cs source had median survival times of 86 and 79 days, respectively, compared to 47 days for untreated animals. Histopathologic examination of the brains of longterm surviving rats, euthanized at 8 or 16 months following BNCT, showed no residual tumor, but dense accumulations of melanin laden macrophages and minimal gliosis were observed. CONCLUSION: Significant prolongations in median survival time were noted in nude rats with intracerebral human melanoma that had received BNCT thereby suggesting therapeutic efficacy. Large animal studies should be carried out to further assess BNCT of intracerebral melanoma before any human trials are contemplated.

Boron neutron capture therapy of brain tumors: enhanced survival following intracarotid injection of sodium borocaptate with or without blood-brain barrier disruption.

PURPOSE: Sodium borocaptate (Na2B12H11SH or BSH) has been used clinically for boron neutron capture therapy (BNCT) of patients with primary brain tumors. The purpose of the present study was to determine if tumor uptake of BSH and efficacy of BNCT could be enhanced in F98 glioma-bearing rats by intracarotid (i.c.) injection of the compound with or without blood-brain barrier disruption (BBB-D). METHODS AND MATERIALS: For biodistribution studies 100,000 F98 glioma cells were implanted stereotactically into the brains of Fischer rats, and 12 days later BBB-D was carried out by i.c. infusion of 25% mannitol, followed immediately thereafter by i.c. injection of BSH (30 mg B/kg body weight). Animals were killed 1, 2.5, and 5 h later, and their brains were removed for boron determination. For BNCT experiments, which were initiated 14 days after intracerebral implantation of 1000 F98 cells, BSH (30 mg B/kg b.wt. was administered intravenously (i.v.) without BBB-D, or i.c. with or without BBB-D. The animals were irradiated 2.5 h later with a collimated beam of thermal neutrons at the Brookhaven National Laboratory Medical Research Reactor. RESULTS: The mean tumor boron concentration after i.c. injection with BBB-D was 48.6 +/- 17.2 microg/g at 2.5 h compared with 30.8 +/- 12.2 microg/g after i.c. injection without BBB-D and 12.9 +/- 4.2 microg/g after i.v. injection. The best composite tumor to normal tissue ratios were observed at 2.5 h after BBB-D, at which time the tumor:blood (T:B1) ratio was 5.0, and the tumor: brain (T:Br) ratio was 12.3, compared to 1.1 and 4.6, respectively, in i.v. injected rats. The mean survival time for untreated control rats was 24 +/- 3 days, 29 +/- 4 days for irradiated controls, 33 +/- 6 days for those receiving i.v. injection of BSH, 40 +/- 8 days for rats receiving i.c. BSH without BBB-D, and 52 +/- 13 days for BBB-D followed by BNCT (p = 0.003 vs. i.v. injected BSH). CONCLUSIONS: Intracarotid administration of BSH with or without BBB-D significantly increased tumor uptake of BSH and enhanced survival of F98 glioma-bearing rats following BNCT. BBB-D may be a useful way to enhance the delivery of both low and high molecular weight boron compounds to brain tumors. Further studies are in progress to assess this approach with other boron delivery agents.

Boron neutron capture therapy of brain tumors: enhanced survival and cure following blood-brain barrier disruption and intracarotid injection of sodium borocaptate and boronophenylalanine.

PURPOSE: Boronophenylalanine (BPA) and sodium borocaptate (Na(2)B(12)H(11)SH or BSH) have been used clinically for boron neutron capture therapy (BNCT) of high-grade gliomas. These drugs appear to concentrate in tumors by different mechanisms and may target different subpopulations of glioma cells. The purpose of the present study was to determine if the efficacy of BNCT could be further improved in F98-glioma-bearing rats by administering both boron compounds together and by improving their delivery by means of intracarotid (i.c.) injection with or without blood-brain barrier disruption (BBB-D). METHODS AND MATERIALS: For biodistribution studies, 10(5) F98 glioma cells were implanted stereotactically into the brains of syngeneic Fischer rats. Eleven to 13 days later animals were injected intravenously (i.v.) with BPA at doses of either 250 or 500 mg/kg body weight (b.w.) in combination with BSH at doses of either 30 or 60 mg/kg b.w. or i.c. with or without BBB-D, which was accomplished by i.c. infusion of a hyperosmotic (25%) solution of mannitol. For BNCT studies, 10(3) F98 glioma cells were implanted intracerebrally, and 14 days later animals were transported to the Brookhaven National Laboratory (BNL). They received BPA (250 mg/kg b.w.) in combination with BSH (30 mg/kg b.w. ) by i.v. or i.c. injection with or without BBB-D, and 2.5 hours later they were irradiated with a collimated beam of thermal neutrons at the BNL Medical Research Reactor. RESULTS: The mean tumor boron concentration +/- standard deviation (SD) at 2.5 hours after i. c. injection of BPA (250 mg/kg b.w.) and BSH (30 mg/kg b.w.) was 56. 3 +/- 37.8 microgram/g with BBB-D compared to 20.8 +/- 3.9 microgram/g without BBB-D and 11.2 +/- 1.8 microgram/g after i.v. injection. Doubling the dose of BPA and BSH produced a twofold increase in tumor boron concentrations, but also concomitant increases in normal brain and blood levels, which could have adverse effects. For this reason, the lower boron dose was selected for BNCT studies. The median survival time was 25 days for untreated control rats, 29 days for irradiated controls, 42 days for rats that received BPA and BSH i.v., 53 days following i.c. injection, and 72 days following i.c. injection + BBB-D with subsets of long-term survivors and/or cured animals in the latter two groups. No histopathologic evidence of residual tumor was seen in the brains of cured animals. CONCLUSIONS: The combination of BPA and BSH, administered i.c. with BBB-D, yielded a 25% cure rate for the heretofore incurable F98 rat glioma with minimal late radiation-induced brain damage. These results demonstrate that using a combination of boron agents and optimizing their delivery can dramatically improve the efficacy of BNCT in glioma-bearing rats.

Bis(bioreductive) alkylating agents: synthesis and biological activity in a nude mouse human carcinoma model.

Chemical investigations leading to the construction of bis(bioreductive) alkylating agents having both conformationally restricted and mobile spacer regions are described. Two targets having the conformationally mobile ethylene spacer group, namely, 2,2'-ethylenebis[6-(hydroxymethyl)-p-benzoquinone] diacetate (3b) and 2,2'-ethylenebis[6-(bromomethyl)-p-benzoquinone] (3c), were studied in vivo and in vitro using an established epithelial/Burkitt lymphoma hybrid cell line (D98/HR1) previously shown to induce carcinomas in nude mice. Inactivity of both test compounds in vitro, the relative resistance of these cells to test drugs in vitro, and the selective antitumor properties of the bis(bromomethyl) analogue in vivo lead to the proposal that this compound undergoes bioreduction to an alkylating species in the hypoxic core of the tumor, thereby exerting its action.

AC/A ratio, age, and refractive error in children.

PURPOSE: To examine how the response AC/A ratio (the amount of accommodative convergence per unit of accommodative response) varies as a function of refractive error and age, to determine whether it is a risk factor for the onset of myopia, and to examine the relation between ocular structural features and the AC/A ratio. METHODS: Accommodation was stimulated by a letter target presented in a Badal system at 0.00, 2.25, and 4.37 D to 828 children aged 6 through 14 years in 1996. Of these, 726 had no myopia in 1996 and were available for examination the following year. Accommodative response and cycloplegic refractive error were measured by autorefraction and convergence by monitoring the relative movement of Purkinje images I and IV. Lens radii of curvature were measured by video phakometry, corneal radius of curvature by topography, and ocular axial dimensions by A-scan ultrasonography. RESULTS: Adjusted for age, the response AC/A ratio was highest in myopes (6.39 delta/D), intermediate in emmetropes (3.94 delta/D), and lowest in hyperopes (3.40 delta/D; P < 0.0001; two-way analysis of variance [ANOVA]). The stimulus AC/A ratio did not vary with refractive error. Adjusted for refractive error, the response AC/A ratio did not change as a function of age. In non-myopic children, having a response AC/A ratio of 5.84 delta/D or more elevated the risk of development of myopia within 1 year by 22.5 times (95% CI = 7.12-71.1). In a subsample of children without myopia who had refractive errors less than +0.75 D, having a response AC/A ratio of 5.84 delta/D or more elevated the risk of development of myopia within 1 year by 3.21 times (95% CI = 1.14-9.07). The AC/A ratio was associated with all measured ocular features except lens spherical volume. Only the negative correlations with refractive error and the shape of the crystalline lens (Gullstrand lens power) were significant in a multiple regression model (adjusted R2 = 0.16). CONCLUSIONS: An elevated response AC/A ratio was associated with myopia and was an important risk factor for its rapid onset. The association between higher AC/A ratios and flatter crystalline lens shapes, as well as other reported features of accommodation in myopia, may be explained by "pseudocycloplegia," which the authors define as tension on the crystalline lens that increases the level of effort needed to accommodate. Accommodative deficits in myopia may be the functional consequences of the underlying anatomy of the enlarged eye.

Ocular predictors of the onset of juvenile myopia.

PURPOSE: The purpose of this study was to identify reliable predictors of the onset of juvenile myopia. METHODS: The data from 554 children enrolled in the Orinda Longitudinal Study of Myopia (OLSM) as nonmyopes with baseline data from the third grade were evaluated to develop a predictive profile for later onset of juvenile myopia. Myopia was defined as at least -0.75 D of myopia in the vertical and horizontal meridians of the right eye as measured by cycloplegic autorefraction (n = 45 children). Chosen predictors were refractive error and the ocular components: corneal power, Gullstrand crystalline lens power, and axial length. Sensitivity and specificity were calculated. Receiver operating characteristic (ROC) curves were generated to evaluate and compare these predictors singly and combined. RESULTS: Refractive error, axial length, Gullstrand lens and pod corneal power were all significant predictive factors for the onset of juvenile myopia. The best single predictor of future myopia onset in the right eye was the right eye's cycloplegic autorefraction spherical refractive error value (mean sphere across 10 readings) at baseline. For a cut point of less than +0.75 D hyperopia in the third grade, sensitivity was 86.7% and specificity was 73.3%. The area under the ROC curve for this mean sphere was 0.880. Producing a logistic model combining mean sphere, corneal power, Gullstrand lens power, and axial length results in a slight improvement in predictive ability (area under the ROC curve = 0.893). CONCLUSIONS: Onset of juvenile myopia can be predicted with moderate accuracy using the mean cycloplegic, spherical refractive error in the third grade. Measurement of other ocular components at this age improves predictive ability, albeit incrementally. Further improvements in the prediction of myopia onset will require the use of longitudinal data in addition to one-time measurement of refractive error and the ocular components.

Tonic accommodation, age, and refractive error in children.

PURPOSE: An association between tonic accommodation, the resting accommodative position of the eye in the absence of a visually compelling stimulus, and refractive error has been reported in adults and children. In general, myopes have the lowest (or least myopic) levels of tonic accommodation. The purpose in assessing tonic accommodation was to evaluate it as a predictor of onset of myopia. METHODS: Tonic accommodation was measured in children enrolled in the Orinda Longitudinal Study of Myopia using an infrared autorefractor (model R-1; Canon, Lake Success, NY) while children viewed an empty lit field or a dark field with a fixation spot projected in Maxwellian view. Children aged 6 to 15 years were measured from 1991 through 1994 (n = 714, 766, 771, and 790 during the 4 years, successively). Autorefraction provided refractive error and tonic accommodation data, and videophakometry measured crystalline lens curvatures. RESULTS: Comparison of the two methods for measuring tonic accommodation shows a significant effect of age across all years of testing, with the lit empty-field test condition yielding higher levels of tonic accommodation compared with the dark-field test condition in children aged 6 through 11 years. For data collected in 1994, mean (+/-SD) tonic accommodation values for the lit empty-field condition were significantly lower in myopes, intermediate in emmetropes, and highest in hyperopes (1.02 +/- 1.18 D, 1.92 +/- 1.59 D, and 2.25 +/- 1.78 D, respectively; Kruskal-Wallis test, P < 0.001; between-group testing shows each group is different from the other two). Age, refractive error, and Gullstrand lens power were significant terms in a multiple regression model of tonic accommodation (R2 = 0.18 for 1994 data). Lower levels of tonic accommodation for children entering the study in the first or third grades were not associated with an increased risk of the onset of myopia, whether measured in the lit empty-field test condition (relative risk = 0.90; 95% confidence interval = 0.75, 1.08), or the dark-field test condition (relative risk = 0.83; 95% confidence interval = 0.60, 1.14). CONCLUSIONS: This is the first study to document an association between age and tonic accommodation. The known association between tonic accommodation and refractive error was confirmed and it was shown that an ocular component, Gullstrand lens power, also contributed to the tonic accommodation level. There does not seem to be an increased risk of onset of juvenile myopia associated with tonic accommodation.

Hemodynamic effects of oral nicorandil in congestive heart failure.

Twenty-five patients with congestive heart failure (CHF) underwent a double-blind randomized study of the acute hemodynamic effects of orally administered nicorandil, a newly developed vasodilator drug. A dose range of 10 to 60 mg was studied. Nicorandil, at a dose of 60 mg, caused statistically significant decreases in systemic systolic and diastolic blood pressure, right atrial pressure, pulmonary capillary wedge pressure, systemic and pulmonary vascular resistance and systolic and diastolic pulmonary arterial pressure. A brief increase in cardiac index attributable to an increase in stroke volume without a change in heart rate was also observed. A dose of 40 mg produced similar results in cardiac index and systemic and pulmonary vascular resistance, but changes in other hemodynamic parameters were much smaller in magnitude and usually not of statistical significance. No significant hemodynamic response was seen to doses of 10 and 20 mg of nicorandil. Duration of action was short with nearly all hemodynamic parameters returning close to baseline within 3 hours. This rapid decrease in activity occurred in concert with a rapid plasma clearance of nicorandil as determined by serial measurements of plasma drug concentration. This study suggests that first-dose orally administered nicorandil elicits favorable, but brief, hemodynamic effects in CHF at doses greater than or equal to 40 mg.

Factors influencing the one-year mortality of dilated cardiomyopathy.

This study was designed to determine prognostic risk indicators of nonischemic dilated cardiomyopathy (DC). Sixty-nine patients were studied. Each patient underwent physical examination (including a history), electrocardiography, echocardiography, cardiac catheterization, 24-hour monitoring and endomyocardial biopsy. The mortality rate at 1 year was 35% (24 deaths). Univariate analysis revealed that the most powerful predictor of prognosis was the left intraventricular conduction delay (p = 0.003). The pulmonary capillary wedge pressure was also predictive of mortality (p = 0.005). Other significant factors, in order of importance, were ventricular arrhythmias (p = 0.007), mean right atrial pressure (p = 0.008), angiographic ejection fraction (p = 0.03), atrial fibrillation or flutter (p = 0.01) and the presence of an S3 gallop (p = 0.05). Factors such as duration of symptoms, presence of mitral regurgitation, end-diastolic diameter, myocardial cell size and percent fibrosis in the biopsy and treatment with vasodilators, antiarrhythmic and anticoagulant drugs were not significant predictors. Multivariate analysis was used to determine which combination of factors could most accurately predict survival and death. The most important factors were left conduction delay, ventricular arrhythmias and mean right atrial pressure. An equation was derived that can be applied to the prognosis of patients with DC. Thus, the clinical assessment of patients with DC can accurately predict the probability of surviving or dying in 1 year.

Growth suppression of human breast carcinoma cells in culture by N-(4-hydroxyphenyl)retinamide and its glucuronide and through synergism with glucarate.

The inhibitory effects of N-(4-hydroxyphenyl)retinamide (HPR) and its glucuronide derivative on the growth of MCF-7 human breast cancer cells in vitro were compared. The results indicate that the glucuronide had slightly greater potency and much less cytotoxicity than the free retinoid. At a concentration of 10(-6) M, HPR inhibited MCF-7 cell growth by approximately 25%, whereas an equimolar concentration of the glucuronide caused a 40% growth inhibition. Higher concentrations of HPR were highly cytotoxic. At a 10(-5) M concentration of the glucuronide, cell viability was 77%, and 65% of the cells were able to resume growth. On the other hand, at 10(-5) M HPR, cell viability dropped to 49%, and only 15% of the cells were capable of resuming growth. The lower cytotoxicity and higher potency of the retinoid glucuronide compared to the parent retinamide suggest that the conjugate may have a chemotherapeutic advantage over the parent compound. The apparent higher efficacy of HPR in combination with glucarate (GT) compared to the single agents could be due to increased net formation of HPR glucuronide conjugate following conversion of GT to the beta-glucuronidase inhibitor, D-glucaro-1,4-lactone. However, HPLC analysis of the cell metabolites did not show any detectable levels of the retinoid glucuronide upon treatment of MCF-7 cells with HPR and GT.

Neutron capture therapy of a rat glioma using boronophenylalanine as a capture agent.

The purpose of the present study was to determine the efficacy of boron neutron capture therapy (BNCT) in treating the therapeutically refractory F98 glioma, using boronophenylalanine (BPA) as the capture agent. F98 glioma cells (10(5)) were implanted stereotactically into the brains of Fischer rats and 15 days later the animals were injected intraperitoneally with 897 mg/kg of D,L-BPA. Between 3 and 9 h after administration blood and tumor boron concentrations exhibited monoexponential decay with half-lives (t1/2) of 4.3 and 5.3 h, respectively. When 803 mg/kg of 10B-L-BPA was administered, the tumor 10B concentration was 29.4 micrograms/g and tumor-to-blood and tumor-to-brain ratios were 3.5 and 3.9, respectively. Seven days after intracerebral implantation of 10(5) F98 cells, BNCT was initiated at the Brookhaven Medical Research Reactor. The median survival time for irradiated controls (no BPA), which had received tumor physical doses of 1.7, 2.6 or 3.5 Gy, were 27, 33 and 38 days, respectively, compared to 24 days for untreated rats (P < or = 0.025-0.0001). The median survival time for BNCT-treated groups that had received 803 mg/kg of 10B-L-BPA 6 h prior to irradiation with total estimated tumor physical doses of 5.7, 8.6 and 11.5 Gy were 32, 37 and 59 days, respectively. Although the enhanced median survival times of two of the BNCT-treated group (8.6 and 11.5 Gy) were significant compared to their matched irradiated controls (P < or = 0.0175-0.0277), all BNCT-treated animals died in less than 160 days. It remains to be determined whether better survival can be achieved using higher doses of BPA and neutrons to treat a tumor, which at this time cannot be cured by any therapeutic modality.

New bacterial species associated with chronic periodontitis.

Recent investigations of the human subgingival oral flora based on ribosomal 16S cloning and sequencing have shown many of the bacterial species present to be novel species or phylotypes. The purpose of the present investigation was to identify potential periodontal pathogens among these newly identified species and phylotypes. Species-specific ribosomal 16S primers for PCR amplification were developed for detection of new species. Associations with chronic periodontitis were observed for several new species or phylotypes, including uncultivated clones D084 and BH017 from the Deferribacteres phylum, AU126 from the Bacteroidetes phylum, Megasphaera clone BB166, clone X112 from the OP11 phylum, and clone I025 from the TM7 phylum, and the named species Eubacterium saphenum, Porphyromonas endodontalis, Prevotella denticola, and Cryptobacterium curtum. Species or phylotypes more prevalent in periodontal health included two uncultivated phylotypes, clone W090 from the Deferribacteres phylum and clone BU063 from the Bacteroidetes, and named species Atopobium rimae and Atopobium parvulum.

Enhanced delivery of boronophenylalanine for neutron capture therapy of brain tumors using the bradykinin analog Cereport (Receptor-Mediated Permeabilizer-7).

OBJECTIVE: Using the well-characterized F98 rat glioma model, the purpose of the present study was to determine whether the delivery of boronophenylalanine (BPA) could be enhanced by prior administration of the bradykinin analog Cereport (Alkermes, Inc., Cambridge, MA) (previously known as Receptor-Mediated Permeabilizer-7), which produces a transient, pharmacologically mediated opening of the blood-brain barrier. METHODS: Two series of experiments were performed in F98 glioma-bearing rats that had received either intracarotid (i.c.) or intravenous infusions of Cereport (at doses ranging from 1.5 to 7.5 microg/kg of body weight), followed by i.c. (or intravenous) injection of BPA (300 mg/kg of body weight). Animals were killed 0.5, 2.5, or 4 hours later, samples of blood, skin, muscle, and eye were obtained, brains were removed, and tumors were excised for boron determination by direct current plasma-atomic emission spectroscopy. RESULTS: Averaged over all time points, i.c. infusion of Cereport significantly enhanced tumor boron uptake (P = 0.0001), compared with the excipient (saline) control values. Tumor boron values were equivalent at 0.5 (36.0 microg/g) and 2.5 hours (38.5 microg/g) after i.c. administration of Cereport and BPA and then decreased by 33% (to 25.7 microg/g) at 4 hours. These tumor boron uptake values were significantly different (alpha = 0.05), compared with values measured at the corresponding times after i.c. administration of BPA without Cereport (22.6, 21.8, and 15.3 microg/g, respectively). Although no time-related effects were observed, i.c. administration of Cereport followed by intravenous administration of BPA also significantly enhanced (alpha = 0.05) tumor boron uptake at 0.5, 2.5, and 4 hours (27.4, 30.3, and 28.0 microg/g, respectively), compared with values obtained without Cereport (11.3, 13.4, and 15.2 microg/g, respectively). Boron levels in normal brain tissue from tumor-bearing and non-tumor-bearing cerebral hemispheres and in blood were not significantly different from those measured in saline-treated control animals. CONCLUSION: This study established that i.c. infusion of Cereport significantly increased delivery of BPA to F98 rat gliomas, and this could enhance the efficacy of boron neutron capture therapy of this tumor.

Enhanced delivery of boronophenylalanine for neutron capture therapy by means of intracarotid injection and blood-brain barrier disruption.

There has been increasing interest in the possible use of boronophenylalanine as a capture agent for boron neutron capture therapy of brain tumors. The purpose of the present study was to determine whether the uptake of boronophenylalanine in F98 glioma-bearing rats could be enhanced by means of intracarotid (i.c.) injection with or without blood-brain barrier disruption (BBB-D). Glioma cells (10(5)) were stereotactically implanted into the right cerebral hemisphere of Fischer rats, and 12 days later, BBB-D was performed by infusing 25% mannitol (1.373 mOsmol/ml) into the right carotid artery and then immediately injecting L-boronophenylalanine (300 mg/kg of body weight) intracarotidly. The animals were killed 0.5, 1, 2.5, and 4 hours later, and the brains were removed for boron determination by direct current plasma atomic emission spectroscopy. BBB-D was assessed by the intravenous injection of Evans blue or horseradish peroxidase, and the barrier-disrupted hemispheres and tumors showed intense staining with each. The mean tumor boron concentration after i.c. injection and BBB-D was 34.8 +/- 6.8 micrograms/g at 2.5 hours compared with 20.3 +/- 6.2 micrograms/g after i.c. injection without BBB-D and 10.7 +/- 0.7 micrograms/g after intravenous injection. No significant differences in boron concentration in muscle, skin, and eye were observed among the different groups. Boron concentrations in the ipsilateral, disrupted hemisphere increased transiently but rapidly returned to background levels by 2.5 hours after BBB-D. The tumor:brain and tumor:blood ratios were 5.2 and 5.6, respectively, compared to 3.2 and 2.1 for intravenous injection groups at 2.5 hours. The present study is the first to show that BBB-D combined with i.c. injection can enhance the tumor uptake of boron compounds for boron neutron capture therapy.

Boron neutron capture therapy of a rat glioma.

The purpose of the present study was to utilize a well-established rat glioma to evaluate boron neutron capture therapy for the treatment of malignant brain tumors. Boron-10 (10B) is a stable isotope which, when irradiated with thermal neutrons, produces a capture reaction yielding high linear energy transfer particles (10B + 1nth----[11B]----4He(alpha) + 7Li + 2.79 MeV). The F98 tumor is an anaplastic glioma of CD Fischer rat origin with an aggressive biological behavior similar to that of human glioblastoma multiforme. F98 cells were implanted intracerebrally into the caudate nuclei of Fischer rats. Seven to 12 days later the boron-10-enriched polyhedral borane, Na2B12H11SH, was administered intravenously at a dose of 50 mg/kg body weight at varying time intervals ranging from 3 to 23.5 hours before neutron irradiation. Pharmacokinetic studies revealed blood 10B values ranging from 0.33 to 10.5 micrograms/ml depending upon the time after administration, a T1/2 of 6.2 hours, normal brain 10B concentrations of 0.5 microgram/g, and tumor values ranging from 1.1 to 12.8 micrograms/g. No therapeutic gain was seen if the capture agent was given at 3 or 6 hours before irradiation with 4 x 10(12) n/cm2 (10 MW-min; 429 cGy). A 13.5-hour preirradiation interval resulted in a mean survival of 37.8 days (P less than 0.01), compared to 30.5 days (P less than 0.03) for irradiated controls and 22.1 days for untreated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved survival after boron neutron capture therapy of brain tumors by Cereport-mediated blood-brain barrier modulation to enhance delivery of boronophenylalanine.

OBJECTIVE: Cereport (Alkermes, Inc., Cambridge, MA), or, as it has been previously called, RMP-7 (receptor-mediated permeabilizer-7), is a bradykinin analog that has been shown to produce a transient, pharmacologically mediated opening of the blood-brain barrier. The purpose of the present study was to determine whether the efficacy of boron neutron capture therapy (BNCT) could be enhanced by means of intracarotid (i.c.) infusion of Cereport, in combination with intravenous (i.v.) injection or i.c. infusion of boronophenylalanine (BPA) in the F98 rat glioma model. METHODS: For biodistribution studies, Fischer rats bearing intracerebral implants of the F98 glioma received i.v. or i.c. injections of 300 or 500 mg/kg body weight (b.w.) of BPA with or without i.c. infusion of 1.5 microg/kg b.w. of Cereport. For therapy studies, BNCT was initiated 14 days after intracerebral implantation of 10(3) F98 cells. The i.v. or i.c. injection of BPA (500 mg/kg b.w.) was given with or without Cereport, and the animals were irradiated 2.5 hours later at the Brookhaven Medical Research Reactor with a collimated beam of thermal neutrons delivered to the head. RESULTS: At a BPA dose of 500 mg/kg b.w., tumor boron concentrations (mean +/- standard deviation) were 55.7 +/- 9.6 microg/g with Cereport versus 33.6 +/- 3.9 microg/g without Cereport at 2.5 hours after i.c. infusion of BPA, and concentrations were 29.4 +/- 9.9 microg/g with Cereport versus 15.4 +/- 3.5 microg/g without Cereport (P < 0.05) after i.v. injection of BPA. After i.c. administration of BPA and Cereport, the tumor-to-blood ratio was 5.4 +/- 0.6, and the tumor-to-brain ratio was 5.2 +/- 2.4. After BNCT with BPA at a dose of 500 mg/kg, the survival time was 50 +/- 16 days for i.c. administration of BPA with Cereport versus 40 +/- 6 days without Cereport (P = 0.05), 38 +/- 4 days for i.v. administration of BPA with Cereport versus 34 +/- 3 days without Cereport (P = 0.02), 28 +/- 5 days for irradiated controls, and 23 +/- 3 days for untreated controls. Compared with untreated controls, there was a 117% increase in lifespan in rats that received an i.c. infusion of Cereport and then BPA, and an 86% increase in lifespan in rats that received i.c. administration of BPA without Cereport. CONCLUSION: These studies have established that i.c. administration of Cereport can not only increase tumor uptake of BPA, but also enhance the efficacy of BNCT.