Enrichment of NRBC in maternal blood: a more feasible method for noninvasive prenatal diagnosis

OBJECTIVE

To assess the efficiency and reliability of the separation of fetal nucleated red blood cells (NRBCs) using the galactose-specific lectin method, we counted the number of NRBCs in the blood of pregnant women at various gestational ages, as well as after amniocentesis and termination.

METHOD

Peripheral blood samples were obtained from (1) 22 singleton pregnant women (between 9 and 34 weeks of gestation) and from 23 women who underwent termination (between 6 and 19 weeks of gestation). To determine whether amniocentesis influences numbers of NRBCs, five samples were obtained (2) before and after the procedure. NRBC enrichment was initially performed using density gradients and subsequently using galactose-specific lectin. The cells were then stained with May-Gruenwald Giemsa (MGG) and counted under a light microscope.

RESULTS

NRBCs were found in all samples, ranging from 1 to 82 (median = 12.5 cells/sample). The multiples of the median (MoM) conversion of the number of cells revealed a raise of 1.66-fold (0.12-6.64) in post-termination samples compared with the control value of 1.00 MoM (0.11-6.92; p = 0.036). The postamniocentesis increase was, instead, 1.11-fold (0.17-4.02), which did not reach statistical significance.

CONCLUSION

All blood samples tested contained NRBCs. Samples obtained after termination yielded more cells than those obtained from women whose pregnancies were going on normally. The number of NRBCs in post-termination samples after MoM conversion differed significantly from those in controls. Although separation of NRBCs was not feasible due to extremely low numbers, our results indicated that NRBCs are detectable in all blood samples from normal pregnant women.

EEG human head modelling based on heterogeneous tissue conductivity

This paper studies the effect of heterogeneous tissue conductivity in a human head model for the EEG forward problem. Firstly, the tissue heterogeneity in conductivity was characterised from measured data in the literature. Then a method was developed to include this feature in modelling. Finally, the effect of tissue heterogeneity on EEG signals was studied. Based on these studies the paper concludes that the inclusion of tissue heterogeneity is significant in accurate head modelling for the EEG problem.

Phase I trial and pharmacokinetic study of oral gimatecan in adults with malignant glioma

1559

Background: Gimatecan (GT) is an orally available camptothecin analogue with potent preclinical antitumor activity. A phase I trial was conducted to determine the maximum tolerated dose (MTD), toxicity profile, and pharmacokinetics (PK) of GT in patients (pts) with recurrent malignant glioma. Methods: GT was given orally once daily for 5 days every 28 days. The starting dose, 1.6 mg/m2 over 5 days, was independently escalated in pts who were and were not concurrently receiving enzyme inducing antiseizure drugs (±EIASD). PK samples were obtained up to 24 after dosing on day 1 and 168 h after dosing on day 5 of cycle 1. Results: A total of 43 pts were enrolled, 18 in the +EIASD arm and 25 in the -EIASD arm, with a median age of 51 years (range, 23–70) and median KPS of 80 (range, 60–100). All pts had prior irradiation and 84% had prior chemotherapy. Dose levels evaluated were 1.6, 3.2, 5.3, 8.0, 11.2, and 15.0 mg/m2 in the +EIASD arm and 1.6, 3.2, 5.3, 6.1, and 8.0 mg/m2 in the -EIASD arm. No dose-limiting toxicities (DLTs) occurred during 49 cycles of therapy in the +EIASD arm with dose escalation terminated at 15.0 mg/m2. Grade 3–4 myelosuppression was the DLT in the -EIASD arm, occurring in 1/11 pts at the MTD of 6.1 mg/m2, and 2/3 pts at 8.0 mg/m2. Gastrointestinal disorders, the most common side effects, were grade >3 in only 7% of pts. Pts in the +EIASD arm received a median of 6 cycles of therapy and there were 2 partial responses and 6 pts with stable disease. Pts in the -EIASD arm received a median of 2 cycles of therapy and 11 pts had stable disease. GT exhibited linear PK. EIASDs significantly affected the PK, decreasing the biological half-life 2-fold from 53 ± 25 to 25 ± 12 h (mean ± SD) and increasing the apparent oral clearance (CL/F) nearly 5-fold from 1.3 ± 1.7 L/h to 6.2 ± 4.3 L/h. CL/F was independent of body surface area. Conclusions: The MTD of GT for pts not receiving EIASDs is 6.1 mg/m2 and an MTD was not established for pts receiving EIASDs due to practical limitations on dose administration. Median duration of disease stabilization or response was 6 cycles for 44% of +EIASD pts and 2 cycles for 44% of -EIASD pts.

[Table: see text]

Phase II study of POLY-ICLC in recurrent anaplastic glioma–A North American Brain Tumor Consortium study

1550

Background: The goals of this study were to determine the 6-month progression free survival (PFS) for patients with recurrent anaplastic glioma (AG) treated with the immune-modulatory agent POLY-ICLC, and to evaluate toxicity. Low dose Poly-ICLC has a direct immune enhancing action which includes an increased antibody response to antigen and activation of NK-cells, T-cells, macrophages and cytokines. Previously documented side effects include transient flu-like symptoms, which responds to acetaminophen and pain related to the intramuscular administration. Methods: Eligibility included age >18 years, recurrent AG, no more than 2 prior relapses, normal laboratory parameters and informed consent. Poly-ICLC was administered at 20mcg/kg 3x/week by intramuscular injection in 4 week cycles continuously. Dose reductions were allowed for toxicities. Patients were assessed for tumor response every 2 months. Treatment continued until tumor progression, unacceptable toxicity or patient withdrawal. The study had a 2 stage design with the initial assessment of 6 month PFS for the first 22 patients with possible expansion to a total of 46 patients, if more than 7 patients of the 22 had a 6 month PFS. Results: As of 12/05, 46 patients were treated (49% males). Median age was 42 years (range 21–70 years) and median KPS was 90. The agent was well tolerated and the toxicity profile was as previously reported. The response rate and 6 month PFS of the 22 patients in the first stage of the study was 9% and 23% respectively. Based on these findings the cohort was expanded to 46 patients. Of the 15 patients in the second cohort with at least 1 post treatment response assessment available, there is 1PR and 7 SD (47%). Conclusions: 6 month PFS for the entire cohort continues to be assessed but preliminary results suggest antitumor activity of this agent in recurrent anaplastic glioma.

No significant financial relationships to disclose.

[TTF-1 expression and its diagnostic application in lung carcinomas]

OBJECTIVE

To detect the expression of thyroid transcription factor 1 (TTF-1) and study its application in the diagnosis of lung carcinomas.

METHODS

Of 134 specimens from lung lobectomy, 105 were primary lung carcinomas including 76 non-small cell carcinomas (NSCLCs), 28 small cell lung cancers (SCLCs) and 1 complex carcinoma (SCLC and SCC), and 29 were metastatic carcinomas. Expression of TTF-1 was detected by immunohistochemistry. The expression level of TTF-1 was graded as, +:6% to 25% of tumor cells positive, ++:26% to 50%, +++:51% to 75%, and ++++:> 76%.

RESULTS

The positive nuclear immunoreactivity of TTF-1 was identified in 23 of 28 SCLCs (82.1%), but none in squamous cell cancer (SCC) (P < 0.001). The positive expression rate of TTF-1 in lung adenocarcinomas (ACs) was 73.8% (31/42). There was no correlation between TTF-1 expression and ACs differentiation or ACs subtypes (P > 0.05). All but one (thyroid follicular carcinoma) metastatic ACs were TTF-1-positive. Mesenchymal component and lymphoid or inflammatory cells were consistently TTF-1-negative.

CONCLUSION

A significant difference of TTF-1 expression may assist in distinguishing SCLC from SCC, lymphoma or inflammatory lesions. Owing to its restrictive expression in lung tissue, TTF-1 might be used to differentiate primary from metastatic adenocarcinoma of the lung.

The impact of inhomogeneous tissue anisotropy on potential distribution within head model

This paper investigates the influence of inhomogeneous head tissue conductivity on EEGs. A head model with inhomogeneity of radial and tangential conductivity is built up. Based on this model the EEG signals are calculated using the finite elements method. The results show that the inhomogeneous radial and tangential conductivity of skull tissue, which has been ignored so far, can cause about 5% difference compared with commonly used homogeneous conductivity head models.

[Use of thyroid transcription factor-1, surfacfant protein-B, cytokeratin 7 and cytokeratin 20 in discrimination between primary and metastatic adenocarcinoma of lung]

OBJECTIVE

To evaluate the utility of thyroid transcription factor-1 (TTF-1), surfactant protein-B, (SP-B) cytokeratin 7 (CK7) and CK20 immunostaining in the discrimination between primary adenocarcinomas and metastatic adenocarcinomas.

METHODS

Formalin fixed, paraffin embedded tissue blocks from 42 primary lung adenocarcinomas and 30 metastatic carcinomas resected during operation were immunostained with monoclonal antibodies to TTF-1, SP-B, CK7, and CK20.

RESULTS

Positive immunostaining with TTF-1 and SP-B was noted in 74% and 52% of primary lung tumor, respectively. The positive immunostaining and specificity of such a combination for discriminating between primary and metastatic adenocarcinoma were 79% and 94%, respectively. All primary lung adenocarcinomas were CK7 positive, 24 (57%) were CK7 positive/CK20 negative and 18 were CK7 positive/CK20 positive in immunophenotype. Colon and breast were the most common sites of metastasis. All metastatic colorectal adenocarcinomas were CK20 positive, 11 (92%) were CK7 negative/CK20 positive and 1 was CK7 positive/CK20 positive in immunophenotype. The results of cytokeratin immunostaining in the metastatic breast tubular carcinomas were similar to those in the primary lung adenocarcinomas: 4 were CK7 positive/CK20 negative and 4 were CK7 positive/CK20 positive. CK7 positive, and TTF-1 or SP-B positive immunophenotype was seen in 33 (79%) primary lung tumors. A combination of CK7 negative, CK20 positive, and TTF-1 and SP-B negative was highly significantly associated with metastatic colorectal carcinomas compared with either primary lung adenocarcinomas or metastatic breast carcinomas (both P < 0.001). A combination of CK7 positive, CK20 negative, and TTF-1 and SP-B negative was highly significantly associated with metastatic breast carcinomas compared with either primary lung adenocarcinomas or metastatic colorectal carcinomas (both P < 0.001).

CONCLUSION

Use of a panel of antibodies including TTF-1, SP-B, CK7 and CK20 is helpful in discriminating between primary and metastatic adenocarcinomas of the lung and suggesting the primary sites of some metastatic adenocarcinomas.

Realistic human head model for EEG from both the geometry and conductivity aspects

This paper describes modelling and simulation of a had model which incorporates both the geometries and conductivities of the human head. It focuses on the inclusion of tissue conductivity inhomogeneity in a realistically-shaped head model, and investigates the impact of this inclusion on the potential distribution within the model. The result show that the impact, which has been neglected in realistic head models so far, is significant.

Thyroid transcription factor-1 in the histogenesis of plumonary sclerosing hemangioma

OBJECTIVE

To investigate the significance of thyroid transcription factor-1 (TTF-1) in the histogenesis of pulmonary sclerosing hemangioma (PSH).

METHODS

With clinicopathologic data of 36 PSH patients obtained, all specimens were stained by immunohistochemical method with a panel of antibodies including TTF-1, SpA, CK, EMA, F-VIII, CD34, Claretinin, HBME, synaptophsin, chromogranin, actin and S-100.

RESULTS

The patients were mostly women with a mean age of 46.7 years and a median age of 48 years. All lesions were solitary and well circumscribed with a mean size of 3.3 cm and a median size of 3 cm. No multiple or metastasis was found. Surface cells (SC) and round cells (RC) were showed in PSH, with more than 90% showing TTF-1 and EMA by immunohistochemical method. CK and SpA were showed in SC, which were not showed in RC. Neuroendocrine cells scattered within RC of PSH were detected in a few cases. Mesothelial, vascular endothelial, neuroendocrine, and myoepithelial markers by immunohistochemical method were negative.

CONCLUSION

Pulmonary sclerosing hemangioma, a benign tumor, originates from the alveolar pneumocytes. Its surface cells are more mature, while the round cells, being primitive respiratory epithelia, may undergo phenotypic differentiation and evolve into mucinous glands or neuroendocrine structure among other components.

Detection of early atherosclerosis with radiolabeled monocyte chemoattractant protein-1 in prediabeteic Zucker rats

BACKGROUND

Migration of monocytes into the arterial wall is an early finding of atherosclerosis. Monocytes are attracted to sites of vascular endothelial cell injury, the initiating event in the development of atheromatous disease, by a chemokine known as monocyte chemoattractant protein-1 (MCP-1). Injured vascular endothelial and smooth muscle cells selectively secrete MCP-1.

OBJECTIVE

This study was performed to determine if radiolabeled MCP-1 would co-localize at sites of monocyte/macrophage concentration in an experimental model of transplant-induced vasculopathy in diabetic animals.

MATERIALS AND METHODS

Hearts from 3-month-old male Zucker rats, heterozygote (Lean) or homozygote (Fat) for the diabetes-associated gene fa, were transplanted into the abdomens of genetically matched recipients. Lean and Fat animals were then fed normal or high-fat diets for 90 days.

RESULTS

At 90 days significant increases (P < 0.013) of MCP-1 graft uptake were seen at imaging and confirmed on scintillation gamma well counting studies in Lean (n = 5) and Fat (n = 12) animals, regardless of diet, 400 % and 40 %, above control values, respectively. MCP-1 uptake of native and grafted hearts correlated with increased numbers of perivascular macrophages (P < 0.02), as seen by immunostaining with an antibody specific for macrophages (ED 2).

CONCLUSION

Radiolabeled MCP-1 can detect abnormally increased numbers of perivascular mononuclear cells in native and grafted hearts in prediabetic rats. MCP-1 may be useful in the screening of diabetic children for early atherosclerotic disease.

Transplant coronary artery disease: a novel model independent of cellular alloimmune response

BACKGROUND

Allograft coronary atherosclerosis (TxCAD) is the leading cause of death after the first year after transplantation. TxCAD is believed to be a form of chronic rejection of the cardiac allografts. This study was undertaken to determine whether TxCAD could develop in the absence of a cellular alloimmune response.

METHODS AND RESULTS

Inbred lean Zucker rats (>26 generations) served as donors and recipients of the cardiac grafts. Donor hearts were explanted at 60 or 90 days. Explanted hearts were processed for coronary artery histological analysis. Cytokine expression was determined by reverse transcription-polymerase chain reaction, and the presence of T cells within the explanted hearts was evaluated by immunohistochemistry. Forty-six transplantations were made, and TxCAD developed in all but one of the transplanted hearts. Overall, one third of the vessels examined were affected by TxCAD, and in roughly half of these vessels, the disease was severe. Native hearts were free of atherosclerosis. Interleukin-2 was absent from the transplanted hearts, and T cells were present in minimal amounts (<1 per low-power field).

CONCLUSIONS

TxCAD developed in the absence of a cellular alloimmune response in these genetically similar donors and recipients. The observed TxCAD was significant and comparable to what is found in rat allografting models.

Comparison study of different head model structures with homogeneous/inhomogeneous conductivity

Most of the human head models used in dipole localisation research, which have been reported in the literature to date, assume a simplified cranial structure wherein the head is modelled as a set of distinct homogenous tissue compartments. The inherent inhomogeneity of the tissues has so far been ignored in these models due to the difficulties involved in obtaining the conductivity characteristics with sufficiently high enough spatial resolution throughout the head. A technique for developing an inhomogeneous head model based on the generation of pseudo-conductivity values from the existing but sparse conductivity values is proposed in this paper. Comparative studies are conducted on different model structures and different mechanisms for generating the pseudo conductivities. An evaluation of the results of these studies as reported in this paper, shows that contrary to current simplifying assumptions, tissue inhomogeneity has a major influence on the computation of electrical potential distributions in the head.

Presenilin-1 binds cytoplasmic epithelial cadherin, inhibits cadherin/p120 association, and regulates stability and function of the cadherin/catenin adhesion complex

Here we show that presenilin-1 (PS1), a protein involved in Alzheimer's disease, binds directly to epithelial cadherin (E-cadherin). This binding is mediated by the large cytoplasmic loop of PS1 and requires the membrane-proximal cytoplasmic sequence 604-615 of mature E-cadherin. This sequence is also required for E-cadherin binding of protein p120, a known regulator of cadherin-mediated cell adhesion. Using wild-type and PS1 knockout cells, we found that increasing PS1 levels suppresses p120/E-cadherin binding, and increasing p120 levels suppresses PS1/E-cadherin binding. Thus PS1 and p120 bind to and mutually compete for cellular E-cadherin. Furthermore, PS1 stimulates E-cadherin binding to beta- and gamma-catenin, promotes cytoskeletal association of the cadherin/catenin complexes, and increases Ca(2+)-dependent cell-cell aggregation. Remarkably, PS1 familial Alzheimer disease mutant DeltaE9 increased neither the levels of cadherin/catenin complexes nor cell aggregation, suggesting that this familial Alzheimer disease mutation interferes with cadherin-based cell-cell adhesion. These data identify PS1 as an E-cadherin-binding protein and a regulator of E-cadherin function in vivo.

[Fluorescence spectra of the rare earth complex-PAA-g-PE films]

The acrylic acid (AA) was grafted onto the PE film surface through UV photograft polymerization. With certain pH value, the grafted films were made to react with the alcohol-water solution of Eu3+ and alpha-thenoyltrifluoroacetone (TTA) or with the chloroform-water solution of Tb3+ and acetyl actone (AcAc), thus causing the preparation of the red or green fluorescent films. As compared with the corresponding Eu(TTA)3.(H2O)2 or Tb(AcAc)3.(H2O)2 solid complexes, both the excitation and emission spectra of the fluorescent films changed remarkably. It's predictable that chemical bond combination has occurred between the rare earth complexes and the macromolecular material. In addition, the IR spectra of the fluorescent films were also observed.

Distant enhancers stimulate the albumin promoter through complex proximal binding sites

The albumin-alpha-fetoprotein locus epitomizes the main features of transcriptional regulation of fetal and adult hepatocyte-specific genes: developmentally regulated promoters and strong distant enhancers. Full enhancer activity required only a proximal albumin-promoter region containing the TATA box, hepatic nuclear factor 1 (HNF1), and nuclear factor Y (NF-Y) sites. Deletion of the HNF1 site abrogated enhancer and promoter activity, whereas methylation of the site reduced all activity by about 3-fold. Deletion of the NF-Y site attenuated activity by about half, but much of the activity could be replaced by juxtaposition of an upstream region (designated distal element IV). Gel shift and competition analysis demonstrated that binding of architectural factors overlapped NF-Y binding. Moreover, a mutation that eliminated NF-Y binding but only minimally perturbed the surrounding region did not affect enhancer function. In plasmids with a second promoter, the enhancers simultaneously stimulated both albumin and alpha-fetoprotein promoters with minimal competition, but surprisingly some mutations in the albumin promoter attenuated expression from both promoters, whereas another uncoupled their expression. With single promoters, the function of the proximal promoter region was controlled by three parameters in the following hierarchy: HNF1 binding > local architecture > NF-Y binding, but integrated two-promoter function had a much greater dependence on NF-Y.

The inhomogeneous conductivity property of cranial tissues and its representation in numerical head models

The inhomogeneous conductivity of cranial tissues is discussed in this paper. A novel approach for including detailed tissue inhomogeneity is proposed and developed using pseudo-conductivity values which are derived from the limited data available from physiological experiments. Simulation studies of the effects caused by the inclusion of inhomogeneity in the EEG forward problem are also presented in this paper. The results suggest that the accurate representation of the tissue inhomogeneity improves the quality of the computed EEG forward solution. Conclusions about the effects of inhomogeneity on the potential distribution are given.

[Influence of icariin on cell membrane of highly metastatic human lung tumor cell line]

In this study, flow cytometry (FCM) and fluorescent probe technique were used to explore the influence of icariin (ICA) on cell membrane of PG. The data suggested that ICA could inhance membrane fluidity of PG and increase the expression of membrane HLA-ABC antigen. This could be one of the anticancer mechanisms of ICA.

Dehydroepiandrosterone reduces proliferation and differentiation of 3T3-L1 preadipocytes

The purpose of these studies was to determine whether the antiobesity actions of dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEAS) observed in vivo are due to an influence on proliferation and/or differentiation in monolayer cultures of 3T3-L1 preadipocytes. For the proliferation study (Exp. 1), cells were grown in plating medium containing DHEA at 0, 5, 25, 50, or 100 microM for 1-4 d. DHEAS was added at the 100 microM level only. For the differentiation study (Exp. 2), cultures were grown in plating medium containing DHEA at 0, 5, 30, 60, 120, or 240 microM for 2-6 d. DHEAS was added at the 240 microM level only. In Exp. 3, the effect of DHEA on mature adipocytes was determined by exposing adipocytes grown in plating medium to DHEA at 0, 75, 125, and 250 microM for 1-4 d. In Exp. 1, preadipocyte proliferation decreased as the level of DHEA increased in cultures of 3T3-L1 cells. DHEAS had no effect on preadipocyte proliferation. The antiproliferative effect of DHEA was partially reversed by the addition of 1 microM mevalonic acid to proliferating cultures containing 25 microM DHEA. In Exp. 2, preadipocyte differentiation decreased as the level of DHEA in the cultures increased. In contrast, neither DHEAS nor mevalonic acid treatment influenced preadipocyte differentiation decreased as the level and duration of DHEA treatment increased in cultures of mature adipocytes. These data support the hypothesis that DHEA, but not DHEAS, is the active form of the steroid that attenuates obesity via altering preadipocyte proliferation and differentiation. The addition of 1 microM mevalonic acid to cultures of 3T3-L1 preadipocytes partially reversed DHEA's antiproliferative effects.

Results of linear accelerator-based radiosurgery for intracranial meningiomas

OBJECTIVE

We report the outcomes of patients treated with linear accelerator-based radiosurgery for intracranial meningiomas at our institution.

METHODS

We reviewed 127 patients with 155 meningiomas treated with stereotactic radiosurgery (SRS) at the study institutions between October 1988 and December 1995.

RESULTS

There were 86 female and 41 male patients (median age, 61.5 yr; range, 19.9-87.9 yr). The median follow-up period was 31 months (range, 1.2-79.8 mo). The median tumor volume was 4.1 cc (range, 0.16-51.2 cc), and the median marginal dose was 15 Gy (range, 9-20 Gy). The tumor locations were as follows: convexity, 31 tumors; parasagittal/falcine, 39 tumors; cranial base, 82 tumors; and ventricular/pineal, 3 tumors. There were 106 benign, 26 atypical, and 18 malignant meningiomas and 5 cases of meningiomatosis. SRS was performed on 48 lesions as the initial treatment and on 107 lesions as adjunct therapy. Freedom from progression was observed in 107 patients (84.3%) at a median time of 22.9 months (range, 1.2-79.8 mo). Twenty patients (15.7%) had disease progression (16 marginal [12.6%] and 4 local [3.1%]) at a median time of 19.6 months (range, 4.1-69.3 mo); the median time for freedom from progression for the benign, atypical, and malignant meningiomas was 20.9, 24.4, and 13.9 months, respectively. Actuarial tumor control for the patients with benign meningiomas was 100, 92.9, 89.3, 89.3, and 89.3% at 1, 2, 3, 4, and 5 years, respectively. Six patients (4.7%) had permanent complications attributable to SRS (median time, 10.3 mo; range, 4.3-18.0 mo); 13 patients died as a result of causes related to the meningiomas (median, 17.5 mo; range, 4.3-37.3 mo). The 1-, 2-, 3-, 4-, and 5-year survival probability for the entire group of patients was 90.3, 82.6, 73.6, 70.5, and 68.2%, respectively; for patients with benign meningiomas, excluding death resulting from intercurrent disease, the survival probability was 97.6, 94.8, 91.0, 91.0, and 91.0%, respectively. The 1-, 2-, 3-, and 4-year survival probability for the patients with atypical and malignant meningiomas was 91.7, 83.3, 83.3, and 83.3% and 92.3, 64.6, 43.1, and 21.5%, respectively.

CONCLUSION

Even though complications from SRS are expected more frequently with large tumors near critical structures, SRS is a safe and effective means of treating selected meningiomas.

A novel nk-2-related transcription factor associated with human fetal liver and hepatocellular carcinoma

A novel cDNA was partially isolated from a HepG2 cell expression library by screening with the promoter-linked coupling element (PCE), a site from the alpha-fetoprotein (AFP) gene promoter. The remainder of the cDNA was cloned from fetal liver RNA using random amplification of cDNA ends. The cDNA encodes a 239-amino acid peptide with domains closely related to the Drosophila factor nk-2. The new factor is the eighth vertebrate factor related to nk-2, hence nkx-2.8. Northern blot and reverse transcriptase polymerase chain reaction analysis demonstrated mRNA in HepG2, two other AFP-expressing human cell lines, and human fetal liver. Transcripts were not detected in adult liver. Cell-free translation produced DNA binding activity that gel shifted a PCE oligonucleotide. Cotransfection of nkx-2.8 expression and PCE reporter plasmids into HeLa cells demonstrated transcriptional activation; NH2-terminal deletion eliminated this activity. Cotransfection into AFP-producing hepatocytic cells repressed AFP reporter expression, suggesting that endogenous activity was already present in these cells. In contrast, cotransfection into an AFP-negative hepatocytic line produced moderate activation of the AFP gene. The cardiac developmental factor nkx-2.5 could substitute for nkx-2.8 in all transfection assays, whereas another related factor, thyroid transcription factor 1, showed a more limited range of substitution. Although the studies have yet to establish definitively that nkx-2.8 is the AFP gene regulator PCF, the two factors share a common DNA binding site, gel shift behavior, migration on SDS-acrylamide gels, and cellular distribution. Moreover, the nk-2-related genes are developmental regulators, and nkx-2.8 is the first such factor associated with liver development.

Pulmonary intralobar sequestration in a patient with cystic fibrosis

We report a case in which pulmonary Intralobar Sequestration (ILS) was an incidental finding at autopsy in an adult with Cystic Fibrosis. Two aberrant arteries from the descending thoracic aorta supplied a bronchial cystic lesion in the right lower lobe. Termination of the segmental bronchus and scar formation proximal to the cyst suggested prior bronchial obliteration. The elastic configuration of the aberrant aortic-derived vessels of the sequestration contrasted sharply with massively hypertrophied, muscular, bronchial arteries which supplied the bronchiectatic upper lobe. Sections of inferior pulmonary ligament were studied in five additional patients with CF but without ILS. Small muscular arteries were consistently noted within the inferior pulmonary ligament. These histologic findings support the concept that the vascular portion of ILS is congenital, whereas the bronchocystic component, in some cases, may be acquired.

Dehydroepiandrosterone-sulfate (DHEAS) reduces adipocyte hyperplasia associated with feeding rats a high-fat diet

OBJECTIVE

To determine if chronic administration of a low level of dehydroepiandrosterone-sulfate (DHEAS) (10 micrograms/ml drinking water) attenuates adiposity in male Osborne-Mendel rats fed low-fat (11% of kcals) vs high fat (46% of kcals) diets.

DESIGN

Rats were randomly assigned to one of four treatment groups for 6 wk in this 2 x 2 factorial study. The main effects tested were diet (low vs high fat) and DHEAS (- or +).

SUBJECTS

Male Osborne-Mendel rats (initial body wt approximately 265 g).

MEASUREMENTS

Adipocyte mass, size and number from two major fat depots (retroperitoneal, epididymal); mass of one subcutaneous adipose depot (inguinal); serum levels of triglycerides, insulin, glucose and DHEAS; brown adipose tissue (BAT) mass; body weight gain, food and water consumption, and residual carcass composition.

RESULTS

DHEAS treatment had no effect on weight gain, food consumption or water intake. DHEAS-treated rats fed the high-fat diet had smaller fat pads containing fewer adipocytes and less carcass lipid than the non DHEAS-treated rats fed the high-fat diet. In contrast, DHEAS-treated rats fed the low-fat diet had similar levels of adipose tissue mass and cellularity compared to control animals fed the low-fat diet.

CONCLUSION

Administration of a low dose of DHEAS (10 micrograms/ml or 0.8 mg/kg body wt/d) in the drinking water of young male Osborne-Mendel rats fed a high-fat diet for 6 wk reduced carcass lipid, fat depot mass and retroperitoneal and epididymal adipocyte number compared to their high-fat-fed cohorts. In this study, the antiobesity effects of DHEAS were specific to the level of dietary fat used.

Tumor-selective transgene expression in vivo mediated by an E2F-responsive adenoviral vector

Recent data suggest that many tumors, such as malignant gliomas, have disrupted pRB function, either because of RB-1 gene mutations or as a result of mutations affecting upstream regulators of pRB such as cyclin D1 or p16/INK4a/MTS1 (ref. 1-5). Tumor suppression by pRB has been linked to its ability to repress E2F-responsive promoters such as the E2F-1 promoter. Thus, a prediction, which has not yet been demonstrated experimentally in vivo, is that E2F-responsive promoters should be more active in tumor cells relative to normal cells because of an excess of "free" E2F and loss of pRB/E2F repressor complexes. We demonstrate that adenoviral vectors that contain transgenes driven by the E2F-1 promoter can mediate tumor-selective gene expression in vivo, allowing for eradication of established gliomas with significantly less normal tissue toxicity than seen with standard adenoviral vectors. Our data indicate that de-repression of the E2F-1 promoter occurs in cancer cells in vivo, a finding that can be exploited to design viral vectors that mediate tumor-selective gene expression.

Viral vector-mediated transduction of a modified platelet factor 4 cDNA inhibits angiogenesis and tumor growth

Chronic systemic delivery of therapeutic proteins, such as inhibitors of angiogenesis, present a number of difficult pharmacological challenges. To overcome these problems for one such protein, we constructed retroviral and adenoviral vectors that express a novel, secretable form of the antiangiogenic protein, platelet factor 4 (sPF4). Vector-mediated sPF4 transduction selectively inhibits endothelial cell proliferation in vitro, and results in hypovascular tumors that grow slowly in vivo. Additionally, tumor-associated angiogenesis is inhibited and animal survival is prolonged, following transduction of established intracerebral gliomas by an sPF4-expressing adenoviral vector. These data support the concept that targeted antiangiogenesis, using virally mediated gene transfer, represents a promising strategy for delivering antiangiogenic therapy.

Immunotoxin therapy of small-cell lung cancer: a phase I study of N901-blocked ricin

PURPOSE

Immunotoxins could improve outcome in small-cell lung cancer (SCLC) by targeting tumor cells that are resistant to chemotherapy and radiation. N901 is a murine monoclonal antibody that binds to the CD56 (neural cell adhesion molecule [NCAM]) antigen found on cells of neuroendocrine origin, including SCLC. N901-bR is an immunoconjugate of N901 antibody with blocked ricin (bR) as the cytotoxic effector moiety. N901-bR has more than 700-fold greater selectivity in vitro for killing the CD56+ SCLC cell line SW-2 than for an antigen-negative lymphoma cell line. Preclinical studies suggested the potential for clinically significant cardiac and neurologic toxicity. We present a phase I study of N901-bR in relapsed SCLC.

PATIENTS AND METHODS

Twenty-one patients (18 relapsed, three primary refractory) with SCLC were entered onto this study. Successive cohorts of at least three patients were treated at doses from 5 to 40 microg/kg/d for 7 days. The initial three cohorts received the first day's dose (one seventh of planned dose) as a bolus infusion before they began the continuous infusion on the second day to observe acute toxicity and determine bolus pharmacokinetics. Toxicity assessment included nerve-conduction studies (NCS) and radionuclide assessment of left ventricular ejection fraction (LVEF) before and after N901-bR administration to fully assess potential neurologic and cardiac toxicity.

RESULTS

The dose-limiting toxicity (DLT) of N901-bR given by 7-day continuous infusion is capillary leak syndrome, which occurred in two of three patients at the dose of 40 microg/kg (lean body weight [LBW])/d. Detectable serum drug levels equivalent to effective in vitro drug levels were achieved at the 20-, 30-, and 40-microg/kg(LBW)/d dose levels. Specific binding of the immunotoxin to tumor cells in bone marrow, liver, and lung was observed. Cardiac function remained normal in 15 of 16 patients. No patient developed clinically significant neuropathy. However, a trend was noted for amplitude decline in serial NCS of both sensory and motor neurons. One patient with refractory SCLC achieved a partial response.

CONCLUSION

N901-bR is an immunotoxin with potential clinical activity in SCLC. N901-bR is well tolerated when given by 7-day continuous infusion at the dose of 30 microg/kg(LBW)/d. Neurologic and cardiac toxicity were acceptable when given to patients with refractory SCLC. A second study to evaluate this agent after induction chemoradiotherapy in both limited- and extensive-stage disease was started following completion of this study.

Noninvasive perfusion imaging of human brain tumors with EPISTAR

A total of 17 patients with histologically proven diagnoses of low-grade astrocytoma (n = 4), high-grade astrocytoma (n = 8), lymphoma (n = 3), and meningioma (n = 2) were examined by using EPISTAR MR imaging. Meningiomas had the highest EPISTAR tumor/white matter contrast and low-grade astrocytomas and lymphomas the lowest. High-grade astrocytomas demonstrated elevated EPISTAR signal with marked regional heterogeneity. There was agreement between tumor vascularity by SPECT and EPISTAR in the five cases where both were done. Our results show that tumor vascularity can be assessed qualitatively by using EPISTAR without the need for contrast medium injection.

In vivo replication-deficient adenovirus vector-mediated transduction of the cytosine deaminase gene sensitizes glioma cells to 5-fluorocytosine

Viral vector-mediated transfer of chemosensitization genes represents a promising new approach to the treatment of cancer. Previous reports have demonstrated that transfection of the bacterial cytosine deaminase (cd) gene into mammalian cells can sensitize them to the otherwise nontoxic nucleoside, 5-fluorocytosine (5-FC). We now report that a replication-deficient adenovirus vector that transduces the cd gene (Ad.CMV-cd) highly sensitizes 9L gliosarcoma cells to 5-FC, and that gene transduction is associated with a potent bystander effect that is not dependent on direct cell-to-cell contact. Stereotactic injection of Ad.CMV-cd into established rat gliomas, followed by systemic administration of 5-FC in vivo, results in prolongation of survival.

[Hypoxia induced increase of MDA and echinocytes from erythrocytes in rabbit's blood with special reference to inhibition of the increase by MPEG-SOD]

When rabbits acutely exposed to hypobaric hypoxia (at imitative altitude 5,000 m, PaO2 = 6.7 kPa), the percentage of the activity of superoxide dismutase (SOD in erythrocyte; EC 1.15.1.1) decreased respectively to 86%, 76%, 81%, 84%, 55%, 81%, 84% and 95% for a period of 0.25, 0.5, 1, 2, 3, 4, 5 and 24 h hypoxia while MDA (malondialdehyde) in erythrocyte and plasma increased significantly during hypoxia periods of 1, 2, 3, 5 and 24 h (n = 5, P < 0.05, P < 0.01 vs. normoxia group). The increase of MDA in plasma could be prevented by vitamin E (V. E, i.p, 1 mg daily for 3 consecative days before hypoxia), but that in erythrocyte did not show significant change probably because the injected V.E. without vehicle cannot penetrate through the erythrocyte membrane effectively. The echinocytes from erythrocytes increased significantly after hypoxia for 24 h (n = 5, P < 0.05 vs. normoxia group). However, by injecting MPEG-SOD (monomethoxypolythlene glycol-SOD) intravenously 30 min before hypoxia, the increase of MDA (both of erythrocyte and plasma) and echinocytes (from erythrocytes) were both inhibited obviously during hypoxia for 24 h (n = 5, P < 0.05, P < 0.01 vs. hypoxia group). It is inferred that the increase of MDA and echinocytes from erythrocytes may be due to lipid peroxidation by superoxide free radicals (O2-.) generated in erythrocytes through Fenton pattern Haber-Weiss reaction during hypobaric hypoxia.

[Acute hypoxia induce free radicals generation in rat's cortex and hippocampus]

Anesthetized rats were ventilated artificially to 10.5%-11.0% O2 in N2 (equivalent to altitude about 5 000 m). PBN (alpha-phenyl-ter-butylnitrone) was injected intravenously 5 min before hypoxia. The experiment results showed that the ESR (electron spin resonance) signal intensity of PBN-spin adduct in cortex and hippocampus both increased significantly during hypoxia (15 min) as compared with normoxia group (n = 5, P < 0.01). In the third group of rats injected with MPEG-SOD (monomethoxy-polyethylene glycol-superoxide dismutase) intravenously 20 min before hypoxia, the ESR signal intensity of PBN-spin adduct in cortex and hippocampus did not decrease significantly under hypoxia for 15 min (compared with hypoxia group, n = 5, P > 0.05). This may be due to the fact that MPEG-SOD could not pass the blood-brain barrier owing to its large molecular weight. The enzyme activity of SOD (superoxide dismutase. EC 1.15.1.1), GSH-Px (Glutathione peroxidase, EC 1.11.1.9) and content of MDA (malondialdehyde) was also determined. The results showed that the hypoxia had no effect on the SOD, GSH-Px activity and MDA content (n = 7 or n = 8, P > 0.05). The above results suggested that ventilation to 10.5%-11.0% O2 in N2 15 min induced free radical generation in rat's cortex and hippocampus, but this generation was not due to decrease of SOD, GSH-Px activity in cortex and hippocampus.

[8%-9% and 12%-13% hypoxic gas induced free radicals generation in rat's left and right myocardium]

Alpha-phenyl-tert-butylnitrone (PBN) was administered intravenously to capture free radicals of rat's myocardium. Rats were exposed to hypoxic gas (8%-9% O2 in N2) for 15 min. The ESR (electron spin resonance) signal intensity of PBN-spin adduct in the left myocardium increased significantly as compared with the normoxia group (n = 5, P < 0.05), but in the right myocardium there was no significant changes between hypoxia and normoxia. Rats exposed to hypoxic gas (12%-13% O2 in N2) were divided into four groups: I (hypoxia for 15 min), II (hypoxia for 60 min), III (hypoxia for 30 min/normoxia for 15 min/hypoxia for 30 min) and IV (injected MPEG- SOD intravenously before hypoxia for 60 min). The ESR signal intensity of PBN-spin adduct of left and right myocardium in group II increased significantly as compared with normoxia group (n = 5, P < 0.01), but the ESR signal intensity of group I didn't show obvious change as compared with normoxia group (n = 5, P > 0.05). In the right myocardium of group III the ESR signal intensity of PBN-spin adduct decreased significantly as compared with group II (n = 5, P < 0.05) and in the left myocardium did not decrease evidently. In the left myocardium of group IV the ESR signal intensity of PBN-spin adduct decreased evidently as compared with group II (n = 5, P < 0.05) and that in the right myocardium did not decrease evidently. When the rats were exposed to 8%-9% hypoxic gas for 15 min and 12%-13% hypoxic gas for 60 min, the SOD (superoxide dismutase, EC 1.11.1.9) activity of myocardium decreased and the content of MDA (malondialdehyde) increased significantly (n = 8, P < 0.05 or P < 0.01). The above results suggested that one way of myocardium free radical gereration may be relevant to decrease of SOD activity. The generation of free radicals pertained chiefly to superoxide free radical in the left myocardium and the membrane structure of myocardium cells might have been damaged largely during hypoxia.

Enhancer sharing in a plasmid model containing the alpha-fetoprotein and albumin promoters

It has been proposed that the alpha-fetoprotein (AFP) enhancers also regulate the adjacent albumin gene, since the -10 kbp albumin enhancer is inactive in a number of cell lines that express albumin. In transfection experiments, the AFP enhancers strongly stimulate the albumin promoter in cells that silence the AFP promoter. These observations led us to develop a plasmid model of AFP-albumin gene switching, in which the albumin and AFP promoters would compete for the three AFP enhancers. However, when AFPCAT + ALBgal genes were combined with the AFP enhancers in one plasmid, both genes were driven at full activity. There was no change in the relative promoter expression over a wide range of transfected DNA concentrations, demonstrating that relative promoter activity was independent of DNA concentration and of promoter concentration, and that neither promoter was limiting the expression of the other. In contrast, a control plasmid containing two albumin promoters showed mutual inhibition, indicating the expected promoter competition. The albumin and AFP promoters noncompetitively shared the three enhancers on this plasmid, resulting in high levels of transcription from both promoters.

A novel hepatocytic transcription factor that binds the alpha-fetoprotein promoter-linked coupling element

We recently characterized a promoter-linked coupling element (PCE) in the rat alpha-fetoprotein (AFP) gene required for strong transcriptional stimulation by distant enhancers (P. Wen, N. Crawford, and J. Locker, Nucleic Acids Res. 21:1911-1918, 1993). In this study, oligonucleotide gel retardation and competition experiments defined the PCE as a 12-bp binding site, TGTCCTTGAACA, an imperfect inverted repeat from -166 to -155 near the AFP promoter. A factor that bound this site (PCF) was abundant in HepG2 nuclear extracts and detectable in extracts from several other AFP-producing hepatocarcinoma cell lines and fetal liver. Hepatocytic cell lines that did not express AFP, nonhepatocytic cell lines, adult liver, and fetal brain did not show the factor. Experiments excluded the possibility that PCF activity was due to binding of glucocorticoid receptor or an AP1-like factor that bound overlapping sites. Competition experiments with several mutant oligonucleotides determined that the optimum PCF binding site was TGTCCTTGAAC(A/T). Mutations decreased binding or totally abolished binding activity. In expression plasmids, PCE mutations strongly reduced gene expression. UV cross-linking to a PCE probe identified peptide bands near 34 kDa. PCF was purified by heparin-Sepharose chromatography followed by affinity binding to oligomerized PCE DNA. The product resolved as a complex of three peptides (PCF alpha 1, PCF alpha 2, and PCF beta, 32 to 34 kDa) on sodium dodecyl sulfate-acrylamide gels. The peptide sizes and gel patterns are unlike those of any of the well-described hepatic transcription factors, and the binding site has not been previously reported. PCF thus appears to be a novel transcription factor.

A phase I study of etanidazole and radiotherapy in malignant glioma

PURPOSE

To determine the maximum tolerable total dose (MTD) of etanidazole (ETA) when administered with external beam radiotherapy (XRT) and as a continuous infusion during stereotactic brachytherapy for patients with malignant glioma (anaplastic astrocytoma or glioblastoma multiforme or mixed cell tumors).

METHODS AND MATERIALS

Seventy previously untreated patients were entered in a Phase I study. Prior to initiation of treatment, patients were stratified according to whether or not they were candidates for interstitial implantation. The implant patients (IMP, n = 17 pt) received accelerated fractionation XRT 20 Gy BID (6 h apart) to 40 Gy in 2 weeks with ETA 2 gm/m2 x 6 doses, a 2 week break and then interstitial implant to 50 Gy (4-7 days) with a continuous infusion of ETA over 90-96 h. The two sequentially conducted nonimplant arms started with accelerated fractionation XRT 2 Gy BID (6 h apart) to 40 Gy in 2 weeks with ETA 2 gm/m2 x 4-5 doses/week. NonIMP 1 arm (n = 38) received a 2-week break before standard fractionated boost XRT of 20 Gy/day for 2 weeks to a total dose of 60 Gy with ETA. NonIMP 2 arm (n = 14) did not have the 2-week break. All patients had plasma pharmacokinetic monitoring of ETA.

RESULTS

The dose-limiting toxicity (DLT) in the IMP group was the cramping/arthralgia syndrome (4) and the cumulative MTD was 26 gm/m2. For both nonIMP 1 and 2 the DLTs were peripheral neuropathy and the cramping-arthralgia syndrome. The MTD for nonIMP 1 was 34 gm/m2 and nonIMP 2, 30 gm/m2.

CONCLUSION

The clinical efficacy and radiation-related toxicity of these regimens are being evaluated. The doses of ETA that can be used with accelerated fractionation and with external beam irradiation plus brachytherapy have been established.

Use of the immunotoxin N901-blocked ricin in patients with small-cell lung cancer

In patients with small-cell lung cancer (SCLC), relapse with resistant disease often causes death. N901-blocked ricin (N901-bR), a murine monoclonal antibody (MAb)-blocked ricin immunotoxin, is a potential therapeutic for SCLC. N901-bR targets CD56, present on SCLC and cells of neuro-ectodermal origin. N901-bR kills up to 5 logs of CD56-positive cells at a concentration of 0.25 nM, while CD56-negative cells require 1000-fold more drug to achieve similar cell kill. We treated 21 patients with relapsed or refractory SCLC with a single 7-day course of N901-bR as a continuous infusion. We determined the MTD and toxicity profile, demonstrated drug binding to tumor cells in biopsies of lung, liver and bone marrow, and determined the time to development of human anti-mouse and anti-ricin antibodies. One patient had a documented PR and 6 patients demonstrated stable disease. Toxicity included transient elevation of liver enzymes, mild thrombocytopenia, hypoalbuminemia, fever, malaise, and evidence of capillary leak syndrome. Toxicities were controllable and reversible. No apparent drug-related central- or peripheral-nervous-system toxicity was noted by serial neurologic examinations, EMGs, and nerve conduction studies. Trials of N901-bR are planned in SCLC patients achieving CR and PR following chemoradiotherapy, and in relapsed/refractory patients. Anti-B4-bR will be added as an immunosuppressant in order to permit delivery of multiple courses of N901-bR. Additional trials will investigate synergy with conventional chemotherapeutics and the use of N901-bR as a sensitizing agent for chemotherapy-resistant tumors.

Transactivation by hepatitis B virus X protein is promiscuous and dependent on mitogen-activated cellular serine/threonine kinases

The X protein of hepatitis B virus (HBV-X) can act as a transactivator of transcription but its mechanism of action remains obscure. We have analyzed HBV-X transactivation in several cell types using 13 unrelated viral and cellular promoters and found that transactivation is more or less apparent in most cell types and is promiscuous and unrelated to specific sequence motifs within the target promoters. In general, though, HBV-X appears to act on enhancer elements since HBV-X had no effect on a minimal promoter, whereas HBV-X was able to transactivate after insertion of an AP-1 minienhancer. Several lines of evidence exclude the possibility that HBV-X interacts directly with the AP-1 enhancer or its binding proteins and suggest that the proximal target of HBV-X is peripheral to the transcription complex. This hypothesis is supported by the observation that inhibition of serine/threonine kinases, which regulate AP-1 activity (phorbol ester down-regulation or staurosporine inhibition of protein kinase C and a dominant negative mutant of Raf-1), blocked the ability of HBV-X to transactivate without affecting basal promoter activity. Furthermore, basal transcription from the AP-1-dependent promoter was increased by overexpression of protein kinase C and Raf-1 but HBV-X was unable to further stimulate, indicating that these kinases act subsequently to HBV-X. These data suggest that transactivation by HBV-X is an indirect result of the activation of cellular serine/threonine kinases including protein kinase C and Raf-1. This mode of action implies that HBV-X may affect other cellular processes, besides transcription, that are regulated by these kinases.

A promoter-linked coupling region required for stimulation of alpha-fetoprotein transcription by distant enhancers

We previously demonstrated that the rat alpha-fetoprotein (AFP) gene has three upstream enhancers that stimulate the AFP promoter additively in HepG2 cells (1). In this paper, deletion analysis demonstrated that a promoter-linked segment from -178 to -155 was required for full activity when the enhancers were distant from the promoter, even at less than their normal genomic distances, but dispensable when the enhancers were moved close to the promoter. This 'promoter-coupling element' appears to interact simultaneously with all three enhancers. Deletion analysis also localized a transcription stimulatory and a negative region in the promoter. Though these latter regions controlled the strength of the isolated promoter, they did not affect 'coupling' to the distant enhancers, and transcription stimulation by these distal promoter elements was small compared to the distant enhancers. Overall, the distant enhancers, acting through the promoter-coupling element, accounted for 70% of the activity of the transfected AFP gene. Footprint analysis with HepG2 nuclear extracts demonstrated protein binding at two sites near the promoter-coupling element. The data indicate a positive transcription control mechanism by which distant enhancers stimulate the AFP promoter through a specific promoter-linked element.

Disseminating tumor cells and their interactions with leukocytes visualized in the brain

Brain tumors are increasingly prevalent. Recent advances focus attention on individual, disseminated tumor cells that cannot be imaged or eliminated. Cells of the immune system may be ideally suited to attack individual tumor cells, but more basic understanding is needed. We describe a rat model, using the lacZ reporter gene, that allows identification of individual tumor cells, and tumor-leukocyte interactions in vivo. The model demonstrates how widely tumor can disseminate, without secondary tumorigenesis or recruitment of nonneoplastic cells. It demonstrates that leukocytes have access to disseminating tumor. Among its many applications, this work lays a foundation for developing cell-mediated immunotherapy against individual brain tumor cells.

Final report of the phase I trial of continuous infusion etanidazole (SR 2508): a Radiation Therapy Oncology Group study

Seventy-eight patients have been treated on a Phase I trial using continuous infusion etanidazole while undergoing brachytherapy for locally advanced tumors. There were two sequential schemata, the first treated 63 patients with doses ranging from 8-23 g/m2 over 48 hr and the second treated 15 patients with doses ranging from 20-23 g/m2 over 96 hr. The tumor sites were: brain (n = 42), cervix (n = 22), and breast (n = 14). Patients received a loading dose of etanidazole of 2 g/m2 followed by a continuous infusion for a total of 48 or 96 hr while radioactive implants were in place. Of the 63 patients in the 48-hr study, 52 were entered at doses of less than or equal to 21 g/m2 and there were no definite neuropathies but two patients with the cramping/arthralgia syndrome. Of the 11 patients entered at 22-23 g/m2, 1 patient had symptoms of peripheral neuropathy (Grade II) and 6 had the cramping/arthralgia syndrome. This is a new syndrome, distinct from the peripheral neuropathy, characterized by transient alterations in sensations consisting of cramping, arthralgias, or tingling that resolved completely at intervals varying from a few hours to about 1 week post-treatment. The cramping/arthralgia syndrome limited dose escalation; therefore, the maximum tolerated dose over 48 hr was determined to be 20-21 g/m2. The 96-hr infusion was limited to patients with recurrent gliomas undergoing stereotactic implantation. To date, 15 patients have been treated with doses of 20-23 g/m2. No toxicity was encountered at doses less than or equal to 22 g/m2. At 23 g/m2, one patient developed Grade III neuropathy and three patients had mild cramping/arthralgia syndrome, for whom the drug was discontinued. Therefore, it appears the maximum tolerated dose at 96 hr will be approximately 23 g/m2, which is 10-15% higher than for the 48-hr infusion.

Enhancer, repressor, and promoter specificities combine to regulate the rat alpha-fetoprotein gene

The upstream transcription control region of the rat alpha-fetoprotein (AFP) gene was analyzed using transient expression of CAT genes in HepG2 cells which express the gene; H4C3 cells which repress the AFP gene but express the albumin gene; and four nonexpressing cell lines. Deletion analysis based on the DNA sequence resolved three upstream enhancers corresponding to the mouse AFP enhancers, but showed additional weak effects from flanking sequences. Quantitative experiments demonstrated that the three enhancers were additive when acting through a single promoter and did not confirm the presence of a distal upstream repressor. All three enhancers stimulated the AFP, albumin, or thymidine kinase (tk) promoter in HepG2, but only the tk and albumin promoters in H4C3. Deletion of a proximal repressor region near the AFP promoter allowed expression in H4C3 cells with the AFP promoter. Thus, the liver-specific developmental repressor is near the AFP promoter, and H4C3 cells provide an in vitro system for analysis of this repressor in transfection assays. The repressor region also blocked expression of the SV40 enhancer through the AFP promoter in hepatic and nonhepatic cell lines, but when this enhancer was combined with an AFP promoter from which the repressor region was deleted, the combination showed expression in all six cell lines studied. AFP expression results from a combination of enhancer, promoter, and repressor activities, and the repressor is functional with a heterologous enhancer in a variety of cells.