The tumor micro-environment in pediatric glioma: friend or foe?

Brain tumors are the leading cause of morbidity and mortality related to cancer in children, where high-grade glioma harbor the worst prognosis. It has become obvious that pediatric glioma differs significantly from their adult counterparts, rendering extrapolations difficult. Curative options for several types of glioma are lacking, albeit ongoing research efforts and clinical trials. As already proven in the past, inter- and intratumoral heterogeneity plays an important role in the resistance to therapy and thus implicates morbidity and mortality for these patients. However, while less studied, the tumor micro-environment (TME) adds another level of heterogeneity. Knowledge gaps exist on how the TME interacts with the tumor cells and how the location of the various cell types in the TME influences tumor growth and the response to treatment. Some studies identified the presence of several (immune) cell types as prognostic factors, but often lack a deeper understanding of the underlying mechanisms, possibly leading to contradictory findings. Although the TME in pediatric glioma is regarded as "cold", several treatment options are emerging, with the TME being the primary target of treatment. Therefore, it is crucial to study the TME of pediatric glioma, so that the interactions between TME, tumoral cells and therapeutics can be better understood before, during and after treatment. In this review, we provide an overview of the available insights into the composition and role of the TME across different types of pediatric glioma. Moreover, where possible, we provide a framework on how a particular TME may influence responses to conventional- and/or immunotherapy.

A flexible proton beam imaging energy spectrometer (PROBIES) for high repetition rate or single-shot high energy density (HED) experiments (invited)

The PROBIES diagnostic is a new, highly flexible, imaging and energy spectrometer designed for laser-accelerated protons. The diagnostic can detect low-mode spatial variations in the proton beam profile while resolving multiple energies on a single detector or more. When a radiochromic film stack is employed for "single-shot mode," the energy resolution of the stack can be greatly increased while reducing the need for large numbers of films; for example, a recently deployed version allowed for 180 unique energy measurements spanning ∼3 to 75 MeV with <0.4 MeV resolution using just 20 films vs 180 for a comparable traditional film and filter stack. When utilized with a scintillator, the diagnostic can be run in high-rep-rate (>Hz rate) mode to recover nine proton energy bins. We also demonstrate a deep learning-based method to analyze data from synthetic PROBIES images with greater than 95% accuracy on sub-millisecond timescales and retrained with experimental data to analyze real-world images on sub-millisecond time-scales with comparable accuracy.

t(1;7;22)(p13;q21;q13) is a novel 3-way variant of t(1;22)(p13;q13) neonatal acute megakaryoblastic leukemia: A case report

Acute megakaryoblastic leukemia (AMKL) is a rare disease, occurring mostly in infants and young children. The chromosomal translocation t(1;22)(p13;q13), resulting in the RBM15-MKL1 fusion gene, is a recurrent and diagnostic translocation in infants with AMKL. The present case report describes a case of a newborn girl, without Down's syndrome, with congenital AMKL. At birth, the infant had hepatosplenomegaly and the peripheral blood count revealed anemia, thrombopenia and leukocytosis, with 28% blasts. Immunophenotyping demonstrated blasts positive for CD34, CD61 and CD42b. Karyotyping of these blasts (R-banding) showed a hitherto unreported chromosomal translocation, t(1;7;22)(p13;q21;q13), a 3-way variant of the t(1;22)(p13;q13) variant. Fluorescent in situ hybridization analysis confirmed the presence of the RBM15-MKL1 fusion gene.

RARE-56. PERITONEAL SEEDING OF A DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR IN A CHILD

Diffuse leptomeningeal glioneuronal tumors (DLGNT) are rare neoplasms of the central nervous system and have been included in the 2016 update of the WHO classification. This is the first description of a DLGNT disseminating to the peritoneal cavity via a ventriculoperitoneal shunt (VPS) in a child. We describe an 11-year old girl who received a VPS for a Dandy-Walker malformation at the age of seven, and was diagnosed with a spinal pilocytic astrocytoma with leptomeningeal metastases six months later. She received chemotherapy (SIOP-LGG protocol) with partial response, and had progressive disease eight months after therapy cessation. Following a novel biopsy, the diagnosis was revised to a DLGNT, with a KIAA1549-BRAF fusion and loss of 1p. She received vinblastine, but was clinically progressive and craniospinal radiotherapy was initiated. 13 months later, she suddenly presented with ascites. The inferior vena cava was compressed due to the ascites, and an abdominal drain was placed, with massive fluid release. Abdominal MRI indicated an omental cake and peritoneal contrast enhancement. Bone metastases were suspected in the iliac and femoral bones. Anatomopathological examination of the ascites showed an atypical cell population, with irregular, hyperchromatic and enlarged nuclei resembling the primary tumor. The cells were positive for synaptophysin, MAP2 and weakly positive for S100. Pan-NTRK staining was negative. The diagnosis of a metastatic localization of the DLGNT was made, due to seeding of tumoral cells via the VPS. Treatment with a MEK-inhibitor was initiated, but was stopped due to progressive disease and she died 3 weeks later.

Abstract P3-10-04: The fully validated NSABP/NRG 8-gene signature which predicted the degree of benefit in the adjuvant setting (B-31 and NCCTG N9831) associates with pCR in the neoadjuvant setting in NSABP clinical trial FB-7

Background: We previously described a predictive signature for trastuzumab benefit which was validated in the adjuvant setting in an independent cohort within NSABP B-31 (the 8-gene signature) (Pogue-Geile et al JNCI, 2013) and in Alliance/NCCTG N9831 (SABCs 2017). The 8-gene signature subtyped B-31 patients into three trastuzumab benefit groups: high HR=0.27, intermediate HR=0.56 and no benefit HR=1.56 based on disease free survival. The 8 gene signature was also predictive of trastuzumab benefit in N9831. HRs were 0.47, P&lt;0.001, 0.6, P=0.02, and 1.54, P=0.375 in the predicted-high, -intermediate and -no benefit groups, respectively based on recurrence free survival (SABCS 2017). The interaction P-value was significant at 0.019 in adjusted Cox models. The RFS at 10 years for trastuzumab-treated pts was 83%, 83% and 72% in the high, intermediate and no benefit groups, respectively. Now we have tested the association of the 8-gene signature groups with pCR in FB-7 which was a 3 arm neoadjuvant study testing the pCR rate of HER2+ breast cancer patients treated with paclitaxel in combination with trastuzumab (T) or neratinib (N) or the combination (T + N).

Methods: RNA-Seq data from FB-7 pretreatment biopsies was used to predict the trastuzumab benefit groups (high, intermediate, and no) for each patient's tumor using the 8 gene signature using methods and cut-offs as previously described (Pogue-Geile et al 2013). The pCR rates (percentages) were tested for treatment interaction with a chi-square test.

Results: The pCR rates were 75%, 53%, and 22%, in the high (N=12), intermediate (N=32) and no benefit groups (N=9), respectively, when analyzed without regard to treatment arm. The pCR rates for the no benefit group and the high benefit groups were significantly different (p=0.030) and there was a significant treatment interaction with the 8-gene benefit group (intp=0.0081). The predicted low and intermediate groups were combined to test whether the 8 gene signature could identify a group of patients whose pCR rates might improve by adding N to T, and referred to it as the low benefit group. This was necessary due to the small numbers of patients in each group. The pCR rate in the low benefit group was higher in patients treated with T+N (9/15, 60%) than in the T arm (6/11, 45%) but these differences were not significant.

Conclusions: This is the first test of the 8-gene signature in the neoadjuvant setting and interpretations of these data should be interpreted cautiously due to the small numbers. However, if these results were validated in another neoadjuvant trial then the 8 gene signature could provide a rationale for selecting patients who would be appropriate for the addition of neratinib or other TKIs to trastuzumab and chemotherapy.

SUPPORT: PUMA Biotechnology, NCI U10CA180868, -180822, UG1-189867, and U24-196067; The Pennsylvania Department of Health. The Department specifically disclaims responsibility for any analysis,interpretations, or conclusions.

Citation Format: Pogue-Geile KL, Wang Y, Srinivasan A, Gavin PG, Kim RS, Song N, Feng H, Lipchik C, Costantino JP, Wolmark N, Lucas PC, Paik S, Jacobs SA. The fully validated NSABP/NRG 8-gene signature which predicted the degree of benefit in the adjuvant setting (B-31 and NCCTG N9831) associates with pCR in the neoadjuvant setting in NSABP clinical trial FB-7 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-04.

Abstract PD3-04: Analysis of ERBB2 (HER2) amplification by ctDNA in a phase Ib dose-escalation trial evaluating trastuzumab emtansine (T-DM1) with neratinib in women with metastatic disease with initially diagnosed HER2+ breast cancer: NSABP FB-10

Background:

In this phase Ib study, the activity of T-DM1 plus N was assessed in patients (pt) previously treated with trastuzumab, pertuzumab, and a taxane (H+P+T). Several mechanisms of resistance have been hypothesized in pts progressing following H+P+T, including acquired alterations in the ERBB (HER) family proteins, reactivation of bypass or parallel pathways, or selective elimination of HER2-overexpressing clones. Loss of HER2 amp has been shown to occur in 25-35% of pts with residual tumor after neoadjuvant therapy or in metastatic disease after initial therapy with chemotherapy and HER2-targeted agents. Data on concordance of HER2 status between tissue and blood is limited. In 7 pts with cfDNA HER2 amp, concomitant tissue was concordant in all 7 pairs and response to anti-HER2 therapy occurred in 6. In our study we have retrospectively analyzed cfDNA in blood samples obtained at study entry.

Methods:

Eligible pts had prior H+P+T as neoadjuvant therapy, or 1st-line metastatic disease, measurable disease, ECOG PS ≤2, and adequate hematologic, renal, and liver function. Pts with stable brain metastases were eligible. Treatment consisted of T-DM1 3.6 mg/kg iv q3wk and N 120, 160, 200, or 240 mg/d using a 3+3 dose-escalation design. HER2+ was determined at initial diagnosis; tissue confirmation at study entry (after H+P+T progression) was not required. Blood was collected in for pharmacokinetic analyses of N peak and trough, and for cfDNA using the Guardant360 assay, which is a 73-gene next-generation cfDNA-sequencing panel that detects SNVs, indels, CNAs, and fusions, utilizing Digital Sequencing and custom bioinformatics methods for error correction. The cut-off for HER2 amp was a copy number of ≥2.0 established by Guardant based on training-set data.

Results:

There were 27 H+P+T-resistant pts enrolled and all pts had a blood sample analyzed for HER2 amp. Eighteen pts were evaluable for efficacy at 6 wks and 11 pts at 12 wks. Dose-limiting toxicity occurred in 6 pts during cycle 1, 1 pt was withdrawn for non-compliance, and 2 pts were withdrawn for disease complications. The recommended phase II dose of N was determined to be 160 mg/d. Responses were seen at all dose-levels of N. Pharmacokinetic analyses did not show a clear relationship with either peak or trough and dose-level. Ten pts showed HER2 amp in blood and 17 were non-amp. Of 18 pts evaluable after 2 cycles (6 wks), 12 pts had an objective response (7 amp; 5 non-amp) and 5 had progressive disease (1 amp; 4 non-amp). At 12 wks, there were 3 CRs and 8 PRs (7 amp; 4 non-amp). All CRs were in amp pts and lasted 364, 510, and 859+ days.

Conclusions:

HER2 amp as determined by cfDNA was found in 10 of 27 pts. The deeper and more prolonged (&gt;12 wk) responses occurred in 7 of 10 amp HER2 pts v 4 of 17 non-amp HER2 pts (p=0.04). In our ongoing phase II study of this regimen concomitant tissue and blood will be analyzed to better understand potential benefit or lack of benefit, with continued use of anti-HER2 therapy after progression on anti-HER2 therapies.

Support: Puma Biotechnology, Inc.

Citation Format: Abraham J, Puhalla SL, Sikov WM, Montero AJ, Salkeni MA, Razaq WA, Beumer JH, Kiesel BF, Buyse ME, Adamson LM, Srinivasan A, Pogue-Geile KL, Allegra CJ, Nagy RJ, Jacobs SA. Analysis of ERBB2 (HER2) amplification by ctDNA in a phase Ib dose-escalation trial evaluating trastuzumab emtansine (T-DM1) with neratinib in women with metastatic disease with initially diagnosed HER2+ breast cancer: NSABP FB-10 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-04.

Mutual interaction between human multipotent adult progenitor cells and NK cells

Human multipotent adult progenitor cells (hMAPCs) are isolated from bone marrow with a more extensive expansion capacity compared to human mesenchymal stem cells (hMSCs) and with the ability to differentiate into endothelium. Like hMSCs, hMAPCs inhibit T-cell proliferation induced by alloantigens. In this study, we tested the interaction between hMAPCs and natural killer (NK) cells. We assessed the susceptibility of hMAPCs to NK cell-mediated lysis and the immunomodulation of hMAPCs on NK cell function during IL-2-driven stimulation and the cytolytic effector phase. Human MAPCs express the ligands PVR and ULBP-2/5/6, which are recognized by activating NK cell receptors. However, they also express MHC class I molecules, which induce inhibitory signals in NK cells. Freshly isolated NK cells at different effector:target ratios did not kill hMAPCs as assessed by an MTT and (51)Cr-release assay, while hMAPCs impaired the cytotoxic activity of resting NK cells against the NK-sensitive K562 leukemia cell line. By contrast, IL-2-stimulated NK cells were capable of killing hMAPCs, and preactivated NK cells were not influenced during their cytotoxic effector function against K562 cells by hMAPCs. When added during the 6-day preactivation phase with IL-2, hMAPCs dose-dependently reduced NK cell proliferation in an IDO-dependent manner, but they did not influence the induction of cytotoxic capacity by IL-2. This study indicates that human MAPCs mutually interact with NK cells.

Overexpression of the NR2A subunit in the forebrain impairs long-term social recognition and non-social olfactory memory

Animals must recognize and remember conspecifics and potential mates, and distinguish these animals from potential heterospecific competitors and predators. Despite its necessity, aged animals are known to exhibit impaired social recognition memory. As the brain ages, the ratio of NR2A:NR2B in the brain increases over time and has been postulated to underlie the cognitive decline observed during the aging process. Here, we test the hypothesis that an increased NR2A:NR2B subunit ratio underlies long-term social recognition memory. Using transgenic overexpression of NR2A in the forebrain regions, we investigated the ability of these mice to learn and remember male and female conspecifics, mice of another strain and animals of another rodent species, the rat. Furthermore, due to the importance of olfaction in social recognition, we tested the olfactory memory in the NR2A transgenic mice. Our series of behavioral experiments revealed significant impairments in the NR2A transgenic mice in long-term social memory of both male and female conspecifics. Additionally, the NR2A transgenic mice are unable to recognize mice of another strain or rats. The NR2A transgenic mice also exhibited long-term memory impairments in the olfactory recognition task. Taken together, our results provide evidence that an increased NR2A:NR2B ratio in the forebrain leads to reduced long-term memory function, including the ethologically important memories such as social recognition and olfactory memory.

Abstract OT1-1-12: NSABP FB-7 Trial: A Phase II Randomized Clinical Trial Evaluating Neoadjuvant Therapy Regimens with Weekly Paclitaxel and Neratinib or Trastuzumab or Neratinib and Trastuzumab Followed by Doxorubicin and Cyclophosphamide with Postoperative Trastuzumab in Women with Locally Advanced HER2-Positive Breast Cancer

Neratinib is an oral, small molecule which acts as an irreversible inhibitor of the pan ErbB receptor tyrosine kinase. Dual ErbB blockade combined with chemotherapy improves efficacy in Her-2 positive breast cancer. Both NeoALTTO (Lancet 2012) and Neosphere (Lancet Oncol 2012) trials demonstrated higher pCR for Her-2 positive breast cancer receiving dual anti-Her-2 neoadjuvant blockade therapy. The purpose of this trial is to determine the activity and safety profile of Neratinib as mono-blockade or in combination with Trastuzumab as dual blockade in neoadjuvant therapy of locally advanced breast cancer (stage IIB, III A, B and C).

Methods: This NSABP Foundation Research Program study (FB-7) is designed as a Phase II, multi-center, three arm clinical trial for patients with Her-2 positive locally advanced breast cancer. 126 patients will be enrolled. The initial two- arm study of Neratinib or Trastuzumab in combination with Paclitaxel began in December 2010. 30 patients were enrolled by December of 2011 at which time the study was placed on hold awaiting the recommended phase II dose of the three drug combination, Neratinib, Trastuzamab and Paclitaxel (NSABP FB-8 trial), which is a Phase I dose-escalation study in women with metastatic Her-2 positive breast cancer. The amended FB −7 trial is now a three arm trial of weekly Paclitaxel and Neratinib or Trastuzumab or Neratinib and Trastuzumab for 4 cycles followed by Doxorubicin and Cyclophosphamide for 4 cycles prior to surgical resection. Patients will then receive postoperative Trastuzumb to complete one total year of Her-2 blockade therapy. The primary goal of this study is to determine the pathologic complete response in breast and axillary lymph nodes following completion of neoadjuvant therapy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-12.

Human multipotent adult progenitor cells are nonimmunogenic and exert potent immunomodulatory effects on alloreactive T-cell responses

Multipotent adult progenitor cells (MAPCs) are bone marrow-derived nonhematopoietic stem cells with a broad differentiation potential and extensive expansion capacity. A comparative study between human mesenchymal stem cells (hMSCs) and human MAPCs (hMAPCs) has shown that hMAPCs have clearly distinct phenotypical and functional characteristics from hMSCs. In particular, hMAPCs express lower levels of MHC class I than hMSCs and cannot only differentiate into typical mesenchymal cell types but can also differentiate in vitro and in vivo into functional endothelial cells. The use of hMSCs as cellular immunomodulatory stem cell products gained much interest since their immunomodulatory capacities in vitro became evident over the last decade. Currently, the clinical grade stem cell product of hMAPCs is already used in clinical trials to prevent graft-versus-host disease (GVHD), as well as for the treatment of acute myocardial infarct, ischemic stroke, and Crohn's disease. Therefore, we studied the immune phenotype, immunogenicity, and immunosuppressive effect of hMAPCs in vitro. We demonstrated that hMAPCs are nonimmunogenic for T-cell proliferation and cytokine production. In addition, hMAPCs exert strong immunosuppressive effects on T-cell alloreactivity and on T-cell proliferation induced by mitogens and recall antigens. This immunomodulatory effect was not MHC restricted, which makes off-the-shelf use promising. The immunosuppressive effect of hMAPCs is partially mediated via soluble factors and dependent on indoleamine 2,3-dioxygenase (IDO) activity. At last, we isolated hMAPCs, the clinical grade stem cell product of hMAPCs, named MultiStem, and hMSCs from one single donor and observed that both the immunogenicity and the immunosuppressive capacities of all three stem cell products are comparable in vitro. In conclusion, hMAPCs have potent immunomodulatory properties in vitro and can serve as a valuable cell source for the clinical use of immunomodulatory cellular stem cell product.

Differentiation potential of human postnatal mesenchymal stem cells, mesoangioblasts, and multipotent adult progenitor cells reflected in their transcriptome and partially influenced by the culture conditions

Several adherent postnatal stem cells have been described with different phenotypic and functional properties. As many of these cells are being considered for clinical therapies, it is of great importance that the identity and potency of these products is validated. We compared the phenotype and functional characteristics of human mesenchymal stem cells (hMSCs), human mesoangioblasts (hMab), and human multipotent adult progenitor cells (hMAPCs) using uniform standardized methods. Human MAPCs could be expanded significantly longer in culture. Differences in cell surface marker expression were found among the three cell populations with CD140b being a distinctive marker among the three cell types. Differentiation capacity towards adipocytes, osteoblasts, chondrocytes, and smooth muscle cells in vitro, using established protocols, was similar among the three cell types. However, only hMab differentiated to skeletal myocytes, while only hMAPCs differentiated to endothelium in vitro and in vivo. A comparative transcriptome analysis confirmed that the three cell populations are distinct and revealed gene signatures that correlated with their specific functional properties. Furthermore, we assessed whether the phenotypic, functional, and transcriptome features were mediated by the culture conditions. Human MSCs and hMab cultured under MAPC conditions became capable of generating endothelial-like cells, whereas hMab lost some of their ability to generate myotubes. By contrast, hMAPCs cultured under MSC conditions lost their endothelial differentiation capacity, whereas this was retained when cultured under Mab conditions, however, myogenic capacity was not gained under Mab conditions. These studies demonstrate that hMSCs, hMab, and hMAPCs have different properties that are partially mediated by the culture conditions.

Aligned silver nanorod arrays as substrates for surface-enhanced infrared absorption spectroscopy

Preferentially aligned silver nanorod arrays prepared by oblique angle vapor deposition were evaluated as substrates for surface-enhanced infrared absorption (SEIRA) spectroscopy. These nanorod arrays have an irregular surface lattice and are composed of tilted, cylindrically shaped nanorods that have an average length of 868 nm +/- 95 nm and an average diameter of 99 nm +/- 29 nm. The overall enhancement factor for chemisorbed organic films of para-nitrobenzoic acid (PNBA) deposited onto the Ag nanorod arrays analyzed by external reflection SEIRA was calculated to be 31 +/- 9 compared to infrared reflection-absorption spectroscopy (IRRAS) obtained from a 500 nm Ag film substrate. This enhancement is attributed to the unique optical properties of the nanorod arrays as well as the increased surface area provided by the nanorod substrate. SEIRA reflection-absorbance intensity was observed with both p- and s-polarized incident radiation with angles of incidence ranging from 25 degrees to 80 degrees . The largest intensity was achieved with p-polarization and incident angles larger than 75 degrees . Polarization-dependent ultraviolet/visible/near-infrared (UV/Vis/NIR) spectra of the nanorod arrays demonstrate that the red-shifted surface plasmon peaks of the elongated nanorods may be partially responsible for the observed SEIRA response. The SEIRA detection limit for the Ag nanorod arrays was estimated to be 0.08 ng/cm(2). Surface-enhanced Raman scattering (SERS) and SEIRA analysis of chemisorbed PNBA utilizing the same nanorod substrate is demonstrated.

Phase II study of topotecan and paclitaxel for patients with previously untreated extensive stage small-cell lung cancer

BACKGROUND

This phase II study was conducted to evaluate the safety and efficacy of the combination of paclitaxel and topotecan for patients with extensive stage small-cell lung cancer (ED-SCLC).

PATIENTS AND METHODS

Previously untreated ED-SCLC patients with Eastern Coperative Oncology Group performance status <2 were eligible. Treatment consisted of topotecan 1 mg/m2 (first three patients received 1.25 mg/m2), on days 1-5, and paclitaxel 135 mg/m2 over 24 h on day 5, every 4 weeks. Prophylactic granulocyte colony-stimulating factor was administered to all patients.

RESULTS

Thirty-two patients received a median of four cycles of chemotherapy. Grade 4 anemia, neutropenia and thrombocytopenia occurred in 13, 31 and 18 patients, respectively. Thirty episodes of febrile neutropenia occurred in 22 patients. Grade 3 fatigue, esophagitis, stomatitis and hypotension occurred in one patient each. Of 26 patients eligible for response evaluation, there were six complete and 12 partial responses (overall response rate 69%). The median survival was 54 weeks. The 1-, 2- and 3-year survival rates were 50%, 10% and 3%, respectively.

CONCLUSIONS

The combination of topotecan and paclitaxel is active as initial therapy in SCLC, but the efficacy is similar to 'standard therapy'. This combination was associated with a high incidence of myelosuppression and febrile neutropenia, at the doses evaluated.

Very late relapse of Hodgkin's disease: a report of five patients

The majority of patients with Hodgkin's disease can be cured with current treatment modalities. Relapses beyond 3 years are rare; however, the outcome for patients in late relapse with standard-dose salvage therapy is excellent. In this article, we report five patients who had such relapses and describe their outcome.

Reduction in dental caries with four concentrations of sodium fluoride in a dentifrice: a meta-analysis evaluation

Information on the effects of fluoride concentrations above 1,100 ppm in dentifrices is not extensive in the literature. The objective of this meta-analysis was to examine and compare the anticaries effectiveness (in terms of DMFS scores) of 1,700 ppm, 2,200 ppm and 2,800 ppm F- ion (as sodium fluoride) dentifrices vs. an 1,100 ppm F- ion (as sodium fluoride) control dentifrice based on results from six double-blind, randomized clinical studies, each conducted over a two- to three-year period. The studies each enrolled approximately 1,200-2,000 male and female school children per treatment group in grades I through 8, and were conducted in areas with low fluoride content water supplies in the states of Indiana, Pennsylvania, Ohio and Oregon. Separate meta-analyses were performed on the study results (DMFS increment scores determined by visual-tactile examinations supplemented with radiographs) for the one-year, two-year and three-year examinations. Comparisons of the 1,700 ppm F-, 2,200 ppm F-, and 2,800 ppm F- groups vs. the 1,100 ppm F- group were based on pooling the effect sizes for these comparisons from the individual studies. The effect sizes were calculated in two different ways, reflecting the analyses that were performed in the original studies: 1) effects based on the sample means and variances; and 2) effects based on the adjusted sample means and mean squared error from an analysis of covariance. The results obtained from this meta-analysis provide evidence that the use of a 2,800 ppm F- ion, as sodium fluoride, dentifrice results in statistically significantly lower caries increment than the use of an 1,100 ppm F- ion, as sodium fluoride, dentifrice. This result was noted after one, two, and three years of dentifrice use. The 1,700 ppm F- and 2,200 ppm F- dentifrice groups showed some directional advantages over the 1,100 ppm F- dentifrice group, however the analysis did not establish these groups as statistically significantly better than 1,100 ppm F-. The meta-analysis based on analysis of covariance results was somewhat more sensitive to treatment group differences than the analysis based on sample means and variances, as was expected.

Relative anti-caries efficacy of 1100, 1700, 2200, and 2800 ppm fluoride ion in a sodium fluoride dentifrice over 1 year

There is limited evidence from clinical trials on the dose response of sodium fluoride dentifrices at concentrations above 1100 ppm fluoride ion, with respect to caries efficacy. This randomized, double-blind study examined the anti-caries effectiveness of sodium fluoride dentifrices containing 1700 ppm, 2200 ppm and 2800 ppm fluoride ion relative to an 1100 ppm fluoride ion control. A population of 5439 elementary schoolchildren, aged 6-15 years, was recruited from an urban central Ohio area with a low fluoride content water supply (<0.3 ppm). Subjects were examined by visual-tactile and radiographic examination at baseline and after 1, 2, and 3 years of using the sodium fluoride dentifrices. Subjects were stratified according to gender, age and baseline DMFS scores derived from the visual-tactile baseline examination and randomly assigned to one of four treatment groups: 0.243% sodium fluoride (1100 ppm fluoride ion), 0.376% sodium fluoride (1700 ppm fluoride ion), 0.486% sodium fluoride (2200 ppm fluoride ion), and 0.619% sodium fluoride (2800 ppm fluoride ion). All products were formulated with the same fluoride compatible silica abrasive. Results after 1 year provided evidence of a positive sodium fluoride dose response. Compared to the 1100 ppm fluoride treatment group, the 1700 ppm fluoride treatment group had an 11.0% reduction in DMFS that was not statistically significant, while the 2200 ppm and 2800 ppm fluoride treatment groups showed statistically significant (P<0.05) reductions of 18.6% and 20.4%, respectively. The reductions in caries delivered by the higher fluoride dentifrices were present across all tooth surface types, but were most pronounced for occlusal surfaces. Results at years 2 and 3 were confounded by a concurrent fluoride rinse program, which involved portions of the study population. While the trends for the higher fluoride dentifrices observed at year 1 remained at years 2 and 3, the difference observed between treatments were substantially less and failed to reach statistical significance (P<0.05). Collectively, the data demonstrate that the 2200 ppm and the 2800 ppm fluoride treatments delivered statistically significantly greater caries efficacy than the 1100 ppm fluoride treatment. This large-scale clinical trial provides evidence of a positive statistically significant dose relationship between dental caries and sodium fluoride in a dentifrice at levels above 1100 ppm fluoride at year 1.

Domain structure and dynamics in the helical filaments formed by RecA and Rad51 on DNA

Both the bacterial RecA protein and the eukaryotic Rad51 protein form helical nucleoprotein filaments on DNA that catalyze strand transfer between two homologous DNA molecules. However, only the ATP-binding cores of these proteins have been conserved, and this same core is also found within helicases and the F1-ATPase. The C-terminal domain of the RecA protein forms lobes within the helical RecA filament. However, the Rad51 proteins do not have the C-terminal domain found in RecA, but have an N-terminal extension that is absent in the RecA protein. Both the RecA C-terminal domain and the Rad51 N-terminal domain bind DNA. We have used electron microscopy to show that the lobes of the yeast and human Rad51 filaments appear to be formed by N-terminal domains. These lobes are conformationally flexible in both RecA and Rad51. Within RecA filaments, the change between the "active" and "inactive" states appears to mainly involve a large movement of the C-terminal lobe. The N-terminal domain of Rad51 and the C-terminal domain of RecA may have arisen from convergent evolution to play similar roles in the filaments.

Kaposi sarcoma after treatment of Hodgkin's disease in a young adult non-AIDS patient: case report and review

We describe a young woman diagnosed with Hodgkin's disease, stage I, at age 20 years. She delayed treatment until age 23, at which time she was considered to have stage II-A disease and was then treated with chemotherapy and involved field irradiation. Two years later, Kaposi sarcoma, which developed on her right shoulder, was excised. Both the Hodgkin's disease and Kaposi sarcoma appeared to be cured, but 3 years later, acute myelogenous leukemia developed and the patient subsequently died in relapse. This is one of the very few instances of a young patient, not infected with the AIDS virus, in whom Kaposi sarcoma developed as a second malignancy after treatment of Hodgkin's disease.

Determination of human immunodeficiency virus-1 protease inhibitors in patient serum using free solution capillary zone electrophoresis

The goal of this study was to develop a fast, inexpensive and quantitative method for serum determination of the human immunodeficiency virus protease inhibitors Crixivan (C), Viracept (V), Invirase (I) or Fortovase (F), and Norvir (N), using common conditions for isolation and analysis. The best separation procedure developed thus far involves uncoated silica capillary and a buffer containing formic acid and acetonitrile. This procedure allows us to analyze three drugs (C, V and I or F) in 15 min. Norvir requires different analytical conditions. These four drugs are isolated from patient sera with a mixture of ethyl acetate and hexane. Sensitivity of the capillary zone electrophoresis protocols is sufficient for the detection of these pharmacological agents at the lowest clinically relevant concentrations (0.1 microgram/ml).

Laser laparoscopic surgery in the treatment of ovarian endometriomas

STUDY OBJECTIVE

To assess the efficacy of laser laparoscopic photocoagulation of endometriomas (2-18 cm) in patients with pain, infertility, or a combination of the two.

DESIGN

Retrospective review of all patients with endometriomas from June 1, 1983, to December 31, 1993.

SETTING

Department of gynecology and obstetrics at a district general hospital and national training center in minimal access surgery.

PATIENTS

One hundred sixty-five women with large endometriomas present at the time of laser laparoscopy.

INTERVENTIONS

Carbon dioxide laser or potassium-titanyl-phosphate laser laparoscopic surgery.

MEASUREMENTS AND MAIN RESULTS

Ninety (74%) of 122 patients reported improvement or resolution of pain; and 30 of 66 achieved a pregnancy, for a cumulative conception rate of 45%.

CONCLUSION

Laser laparoscopy is a practical, safe, and effective technique for the management of large ovarian endometriomas.

Endometrial resection follow up: late onset of pain and the effect of depot medroxyprogesterone acetate

OBJECTIVE

To observe longer term (9 to 18 months) follow up of women after a transcervical resection of the endometrium (TCRE) and the effect of post-operative medroxyprogesterone acetate on the results.

DESIGN

An observational study.

SETTING

A district public hospital and a nearby private hospital in Sydney, Australia.

SUBJECTS

Sixty-one women who underwent TCRE from January to December 1991 were contacted 9 to 18 months after the procedure. They were questioned about symptoms and levels of satisfaction at six months, 12 months and at the time of interview, 9-18 months after the procedure. The 27 women treated from 1 January to 31 August 1991 were given medroxyprogesterone acetate 150 mg at the time of surgery. From 1 September to 31 December 1991 no medroxyprogesterone acetate was given (32 women). Two women underwent immediate hysterectomy, and are included as unsuccessful TCREs but are excluded from description of effects of medroxyprogesterone acetate on the results of TCRE.

RESULTS

Late onset, defined as after 12 months, of pain with or without bleeding occurred in 7 out of 52 women (13.5%). Overall, 49 out of 61 women (80.3%) were satisfied with the operation at the time of interview, 9 to 18 months post-operatively. Success rates, measured by satisfaction, were 89% (24/27) in the medroxyprogesterone acetate group and 75% (24/32) in the no medroxyprogesterone acetate group.

CONCLUSION

Follow up after endometrial resection revealed that a definite subgroup of women develop late onset of pain with or without bleeding. Results at four to six months do not necessarily correlate with longer term outcomes. This needs to be investigated with larger, long term follow up studies, as does the apparently beneficial effects of medroxyprogesterone acetate on the long term results of TCRE.

Conformations of adducts and kinetics of binding to DNA of the optically pure enantiomers of anti-benzo(a)pyrene diol epoxide

Kinetic flow dichroism studies indicate that the (+) enantiomer of 7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene physically bound at intercalative-type sites in double-stranded DNA undergoes covalent binding reactions to form adducts at external binding sites. The conformation of the non-covalent complex derived from the (-) stereoisomer is also intercalative in nature, but the conformations of the covalent adducts are heterogeneous and are characterized by both intercalative-type and external conformations. It is suggested that the distinctly higher biological activity of the (+) enantiomer relative to the activity of the (-) enantiomer may be related to the preponderance of 7,8,9-triol benzo(a)pyrene residues covalently linked to deoxyguanine and located at external binding sites in the DNA adducts.

Stereoselective covalent binding of anti-benzo(a)pyrene diol epoxide to DNA conformation of enantiomer adducts

The conformation of adducts derived from the reactions and covalent binding of the (+) and (-) enantiomers of 7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (anti-BaPDE) with double-stranded calf thymus DNA in vitro were investigated utilizing the electric linear dichroism technique. The linear dichroism and absorption spectra of the covalent DNA complexes are interpreted in terms of a superposition of two types of binding sites. One of these conformations (site I) is a complex in which the plane of the pyrene residue is close to parallel (within 30 degrees) to the planes of the DNA bases (quasi-intercalation), while the other (site II) is an external binding site; this latter type of adduct is attributed to the covalent binding of anti-BaPDE to the exocyclic amino group of deoxyguanine (N2-dG), while site I adducts are attributed to the O6-deoxyguanine and N6-deoxyadenine adducts identified in the product analysis of P. Brookes and M.R. Osborne (Carcinogenesis (1982) 3, 1223-1226). Site II adducts are dominant (approximately 90% in the covalent complexes derived from the (+) enantiomer), but account for only 50 +/- 5% of the adducts in the case of the (-)-enantiomer. The orientation of site II complexes is different by 20 +/- 10 degrees in the adducts derived from the binding of the (+) and the (-) enantiomers to DNA, the long axis of the pyrene chromophore being oriented more parallel to the axis of the DNA helix in the case of the (+) enantiomer. These findings support the proposals by Brookes and Osborne that the difference in spatial orientation of the N2-dG adducts of (-)-anti-BaPDE together with their lower abundance may account for the lower biological activity of the (-) enantiomer. The external site II adducts, rather than site I adducts, appear to be correlated with the biological activity of these compounds.

Linear dichroism studies of conformations of carcinogen-DNA adducts application to covalent complexes derived from the reactions of the two enantiomers of 9,10-epoxy-9,10,11,12-tetrahydrobenzo(e)pyrene with DNA

The conformations of the adducts derived from the covalent binding of the two enantiomeric forms of 9,10-epoxy-9,10,11,12-tetrahydrobenzo(e)pyrene (BePE) with native DNA were investigated by the electric linear dichroism technique. Both enantiomers give rise to two major adducts, one of which appears to be a quasi-intercalative site (I) while the other one is an external binding site (II). While the overall linear dichroism spectra are similar, in the case of the (-) enantiomer there is a greater contribution of site II adducts. These results are markedly different from the ones obtained with the two enantiomers of anti-benzo(a)pyrene-7,8-diol-9,10-epoxide (BaPDE), where the (+) enantiomer gives rise almost exclusively to site II binding, while the (-) enantiomer gives rise to both site I and site II covalent binding. The differences in the heterogeneity of binding between BePE and anti-BaPDE enantiomers may be due to the absence of hydroxyl groups in BePE which, in the case of BaPDE, are an important factor in determining the stereoselective properties of the covalent binding to double-stranded DNA.

1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU)-induced pulmonary fibrosis

Clinical data are presented on 14 patients undergoing BCNU therapy for a primary intracranial glioma (11 biopsied, 3 suspected) in whom pulmonary fibrosis developed as a consequence of the therapy. Pulmonary diffusion abnormalities, dry hacking cough, and chest x-ray changes herald the onset of the process. Microscopic evaluation of lung specimens revealed a wide spectrum of change including hyaline membrane formation, alveolar septal thickening, interstitial fibrosis, and granuloma formation. It is concluded that BCNU causes pulmonary fibrosis that is primarily but not necessarily dose-related and may not be reversible.

Use of plasma pharmacokinetics to predict and prevent methotrexate toxicity

To correlate the pharmacokinetics and toxicity of methotrexate, we measured the drug's clearance from plasma after 395 high-dose, six-hour infusions given to 78 patients. After 375 infusions, 48 hour methotrexate levels fell within 2 standard deviations of the mean for nontoxic infusions, and myelosuppression did not occur. Methotrexate concentrations exceeded the range for nontoxic patients (mean +/- 2 standard deviations) after 20 infusions. Serious myelosuppression occurred after six of these 20 infusions, including five of 12 infusions associated with 48-hour drug concentrations above 9 X 10(-7) M. In seven patients with 48-hour concentrations above 9 X 10(-7) M, the absence of toxicity could be attributed to subsequent rapid clearance of the drug; four of these patients also received large doses of supplemental leucovorin (50 to 100 mg per square meter every six hours). Determination of methotrexate concentration in plasma thus identified patients at high risk of toxicity, a group that may benefit from supplemental leucovorin rescue.

Dose-dependent metabolism of methotrexate in man and rhesus monkeys

Humans and rhesus monkeys receiving high-dose methotrexate (MTX) (greater than 50 mg/kg) excrete significant quantities of the metabolite, 7-hydroxy-MTX. This metabolite, though 200-fold less potent than MTX as an inhibitor of mammalian dihydrofolate reductase, is of very limited aqueous solubility, and thus may contribute to the renal toxicity of the high-dose regimen. The metabolite was not observed in previous pharmacologic studies in which conventional doses of MTX were administered (less than 10 mg/kg).

Beta-aminoaciduria in patients with Burkitt's lymphoma

The massive amounts of beta-aminoisobutyric acid (beta-AIBA) in the urine of Burkitt's lymphoma patients were measured along with other alpha-amino acids and beta-alanine present in normal and decreased levels. The ratios of the amount of beta-AIBA to beta-alanine, in mumoles/kg urine collected in 24 hours, were elevated for all patients. The degree of elevation of beta-AIBA excretion and the ratio of the two beta-amino acids appeared to be related to the amount of tumor mass present. These analyses may have possible value in monitoring patients with Burkitt's lymphoma during their disease course.

7-Hydroxymethotrexate as a urinary metabolite in human subjects and rhesus monkeys receiving high dose methotrexate

Human subjects and rhesus monkeys receiving the antitumor agent methotrexate at the high dose levels recently introduced into clinical use (greater than 50 mg/kg) excrete significant amounts of the metabolite 7-hydroxymethotrexate. The metabolite is not detected in these species after methotrexate therapy at conventional dose levels. The evidence indicates that in primates, the in vivo conversion of methotrexate to 7-hydroxymethotrexate is a dose-dependent phenomenon, with the enzyme system(s) catalyzing the reaction having a low affinity for the drug.

Candida arthritis treated with amphotericin B

This report describes a patient with acute lymphoblastic leukemia who developed arthritis of the knee caused by Candida tropicalis. Systemic therapy with amphotericin B apparently suppressed but did not eliminate the infection. Resolution of the arthritis occurred only after three intra-articular injections of amphotericin B. Intra-articular administration of amphotericin B may be a useful adjunct to systemic antifungal therapy in the treatment of these infections.

Potential biologic markers in Burkitt's lymphoma

Specific biochemical molecules used as potential biologic markers, including modified nucleosides, polyamines, and pyrimidine catabolic end-products, were quantitatively measured in the urine of seven patients with Burkitt's lymphoma before, during, and after one or more courses of therapy. The results of this preliminary study demonstrated that patients with this disease frequently excrete significantly increased amounts oof modified nuceleosides (considered to be derived primarily from transfer ribonucleic acid), polyamines, and beta-aminoisobutyric acid during the course of their disease. With successful treatment and rapid destruction of tumor cells, a concomitant rise in these molecules occurs. Elevations were observed prior to chemotherapy and changes in levels associated with treatment or tumor progression appeared to correlate with disease status and to aid in assessing antitumor response. Periodic follow-up analysis of these molecules may be helfful in appraising relapse or recurrence of the malignancy prior to overt evidence of tumor by existing clincial means.