Response of cultured cells from the epidermis and the buccal mucosa to TGF-beta 1 and comparison to interferon-gamma

Normal human cells from epidermis and from buccal mucosa were cultured to confluence in three media with graded differentiation potential (at low Ca2+, high Ca2+, and supplemented with serum) and treated with transforming growth factor beta 1 (TGF-beta 1), as had been done previously with interferon-gamma (IFN-gamma). The response of the cells to TGF-beta 1 was monitored in terms of the expression of regulatory genes associated with proliferation and differentiation (cdc2, c-myc, p53) and of genes for structural proteins expressed at varying stages of maturation (keratins K5 and K10, involucrin, flaggrin). For both tissues, the results obtained with both agents were very similar for those genes expressed in the basal cells (cdc2, c-myc, p53, K5), regardless of their function, but diverged for the other genes, which are expressed in the suprabasal cells. Another related contrast is that, although IFN-gamma induced apoptosis in epidermal keratinocytes cultured in the serum containing medium, TGF-beta 1 did not. Thus, the two agents appear to affect the earlier stages of cell differentiation in the same way but to differ at the later stages, particularly in that IFN-gamma pushes maturation further than does TGF-beta 1).

Adenovirus-mediated thymidine kinase gene transduction in human epithelial ovarian cancer cell lines followed by exposure to ganciclovir

In an effort to develop gene therapy for ovarian cancer efficacy and toxicity of adenovirus-mediated transfer of the HSV-TK gene followed by administration of ganciclovir were studied in two human epithelial ovarian cancer cell lines Ov-ca-2774 and Ov-ca-1225. 100% transduction was achieved in both cell lines at MOIs of 7 and 15 as demonstrated by X-Gal staining. No toxicity of virus alone was observed at MOIs up to 30. GCV was not toxic up to 200 micrograms/ml. Cell killing efficacy was shown to be dependent on MOI as well as GCV dose. The "bystander effect" of ADV/RSV-TK was quantified by mixing experiments and found to be dependent on the proportion of ADV/RSV-TK positive cells as well as the GCV dosage. Similar results were observed in both cell lines. ADV/RSV-TK mediated gene therapy may be a promising approach in ovarian cancer.

Adenoviral-mediated thymidine kinase gene transfer into the primate brain followed by systemic ganciclovir: pathologic, radiologic, and molecular studies

Transduction of experimental gliomas with the herpes simplex virus thymidine kinase gene (HSV-tk) using a replication-defective adenoviral vector (ADV/RSV-tk) confers sensitivity to ganciclovir (GCV) leading to tumor destruction and prolonged host survival in rodents. To determine treatment tolerance prior to clinical trials, we conducted toxicity studies in 6 adult baboons (Papio sp.). The animals received intracerebral injections of either a high dose of ADV/RSV-tk [1.5 x 10(9) plaque-forming units (pfu)] with or without GCV, or a low dose of ADV/RSV-tk (7.5 x 10(7) pfu) with GCV. The low dose corresponded to the anticipated therapeutic dose; the high dose was expected to be toxic. Magnetic resonance imaging (MRI) of the brain was obtained before treatment and at 3 and 6 weeks after treatment. Animals receiving the high-dose vector and GCV either died or became moribund and required euthanasia during the first 8 days of treatment. Necropsies revealed cavities of coagulative necrosis at the injection sites. Animals receiving only the high-dose vector were clinically normal; however, lesions were detected with MRI at the injection sites corresponding to cystic cavities at necropsy. Animals receiving the low-dose vector and GCV were clinically normal, exhibited small MRI abnormalities, and, although no gross lesions were present at necropsy, microscopic foci of necrosis were present. The vector sequence was detected by polymerase chain reaction (PCR) at the injection sites and in non-adjacent central nervous system tissue in all animals. Recombinant DNA sequence was detected outside of the nervous system in some animals, and persisted up to 6 weeks. The viral vector injections stimulated the production of neutralizing antibodies in the animals. No shedding of the vector was found in urine, feces, or serum 7 days after intracerebral injection. This study suggests that further investigations including clinical toxicity trials of this form of brain tumor therapy are warranted.

Adenovirus-mediated gene transfer of herpes simplex virus thymidine kinase in an ascites model of human breast cancer

In this study, the growth of locally disseminated breast cancer was modeled using a human breast cancer cell line, MDA-MB-435A, adapted to grow as an ascites tumor in athymic mice. Ex vivo infection of MDA-MB-435A cells with adenovirus containing the herpes simplex virus thymidine kinase gene (HSV-tk) were injected into the intraperitoneal cavity of athymic mice. Ganciclovir (GCV) treatment resulted in prolonged median survival (117 vs. 34 days, p < 0.001) compared to untreated or control animals. Adenovirus containing HSV-tk also demonstrated therapeutic activity after in vivo transduction resulting in prolongation of median survival after GCV treatment (32 vs. 25 days, p < 0.001). However, compared to ex vivo treatment, the effect was modest. In an attempt to increase survival, the viral dose was increased three-fold. Instead of prolonging survival, the increased dose resulted in more toxic deaths. Necropsy demonstrated that the most significant histologic abnormality was marked, diffuse, cytomegalic changes in the liver. Polymerase chain reaction (PCR) analysis of hepatic DNA demonstrated the presence of the virus in the affected tissue. Similar host toxicity and hepatic abnormalities were seen in non-tumor-bearing mice treated with ADV/RSV-tk plus GCV. In conclusion, adenoviral vectors can successfully transfer genes in vivo to cancer cells growing as ascites tumors. Transduction with HSV-tk followed by GCV treatment can prolong survival in this model system of disseminated disease, however toxicity can be substantial. Further refinement in targeting expression of HSV-tk will be required to enhance the therapeutic benefit.

A micro liquid chromatographic assay for the determination of plasma-unbound atenolol

An improved high performance liquid chromatographic assay for plasma-unbound atenolol is described. The assay has a wide range (10-5000 ng ml-1) of linearity and a detection limit of 5 ng ml-1 (or 0.1 ng per injection) with acceptable intra- and inter-assay reproducibilities using small volumes of plasma (100 microliters). Following administration of a single dose of atenolol to the rat, nine blood samples were collected over a period of 8 h. These samples were analyzed for atenolol concentrations by a sensitive and specific microbore high performance liquid chromatograph with a photodiode-array detector. This multi-channel detector was used to acquire spectral information on atenolol and demonstrated a superior performance in comparison to all other techniques in that both qualitative and quantitative information were acquired with the system. Because of it sensitivity and applicability to plasma analysis, the assay can be used for pharmacokinetic studies and is valuable in therapeutic drug monitoring.

Adenoviral-mediated herpes simplex virus-thymidine kinase gene transfer in vivo for treatment of experimental human melanoma

To assess the efficacy of an in vivo adenoviral-mediated cytotoxic gene therapy, human melanomas were established in nude mice and transduced with herpes simplex virus-thymidine kinase (tk) followed by treatment with ganciclovir (GCV). In initial experiments, adenovirus (adv) containing the beta-galactosidase reporter gene was employed to determine melanoma cell infectivity in vitro. In comparison to murine melanoma cell lines B16 and K1735-M2, human A375-SM cells exhibited up to a 10-fold greater susceptibility to adenoviral transduction, similar to the degree of infectivity found for human epidermal HaCaT cells. In addition, human A375-SM melanoma cells exhibited a greater sensitivity in vitro to the cytotoxic effects of transduction with tk-adv and treatment with GCV, which was mediated by a strong bystander effect. In vivo, intratumoral injection of relatively large human melanomas (160 mm3) with 1.2 X 109 pfu of tk-adv, followed by intraperitoneal GCV treatment (60 mg/kg twice daily) over 4 days, typically resulted in a 50% reduction in melanoma growth rate compared to mock or untreated controls. Moreover, histometrical analysis employing a rigorous computerized imaging system revealed that the residual viable tumor area in the tk-adv/GCV-treated group was only one-fifth that of solvent controls. These data show that adv is a highly efficient in vivo gene delivery system to treat experimental human melanomas. In comparison to a previous murine melanoma study, human melanomas appeared to exhibit a greater sensitivity to this cytotoxic treatment in vivo, which may hold significant promise for development of effective gene therapy modalities to treat melanoma in humans.

In vivo gene therapy of ovarian cancer by adenovirus-mediated thymidine kinase gene transduction and ganciclovir administration

Efficacy and toxicity of adenovirus-mediated transfer of the herpes simplex virus thymidine kinase gene followed by administration of ganciclovir were studied in vivo. A human epithelial ovarian cancer animal model was established in nude mice using the serous ovarian adenocarcinoma cell line Ov-ca-2774. Intraperitoneal (ip) injection of 1 x 10(8) Ov-ca-2774 cells resulted in tumor growth and formation of malignant ascites in all 15 animals. In a prospective randomized experimental design mice were treated 1, 3, or 7 days after ip injection of 1 x 10(8) cells with ip injection of 2 x 10(8), 6.7 x 10(8), or 2 x 10(9) pfu ADV.RSV-TK followed by administration of ganciclovir (10 microgram /ml, ip, bid) for 6 consecutive days. End points were survival and toxicity. Mice treated with GCV or HSV-TK alone died from 14.4 +/- 1.7 to 19.5 +/- 3.5 days after treatment as did untreated controls. No toxicity of ADV.RSV-TK was found up to 2 x 10(9) pfu (2 x 10(11) particles). The mice with the highest tumor burden treated with the lowest viral dose lived significantly longer than controls (P < 0.05). Median survival in all other groups of mice treated with ADV.RSV-TK plus GCV was even longer (P < 0.01). Treatment benefit was dependent on ADV/RSV-TK dose and tumor burden. Adenovirus-mediated thymidine kinase gene therapy is a realistic approach to ovarian cancer treatment that warrants investigation in the clinical setting.

Combination gene therapy for oral cancer in a murine model

Combination therapy involving adenovirus-mediated transfer of the genes for herpes thymidine kinase (tk) and murine interleukin 2 (mIL-2) was used to treat head and neck cancer in C3H/HeJ mice. Tumors were generated by transcutaneous injection of 5 X 10(5) murine squamous carcinoma cells into the floor of the mouth of these syngeneic mice. After 1 week, recombinant adenoviral vectors containing both therapeutic and control genes in various combinations were injected directly into the established tumors, and subsequently all mice were administered ganciclovir twice daily (25 mg/kg) for 6 days. Animals receiving either tk alone or tk + mIL-2 demonstrated significant tumor regression compared to mIL-2 alone or control vector-treated mice (P < 0.008). Mice receiving both tk + mIL-2, however, also demonstrated a significantly greater regression of tumors compared to those treated with tk alone (P<0.008), indicating a synergistic effect of the combination gene therapy. This synergism was confirmed in survival studies because tk + mIL-2 treated mice showed increased survivals (P=0.0002). Clinical and microscopic exam of regional surrounding tissues and distant organs showed no evidence of cytotoxicity for representative animals in each experimental group. These results suggest that combination tk and mIL-2 gene therapy may provide a powerful new modality for the treatment of head and neck cancer.

Intelligence quotient in childhood acute lymphoblastic leukemia after prophylactic treatment in central nervous system with 18 Gy cranial irradiation and intrathecal methotrexate

The purpose of this study is to evaluate whether central nervous system prophylactic treatment (CNSP) with cranial irradiation therapy (CrRT) 18 Gy and intrathecal methotrexate would decline the intelligence quotient (IQ) scores of children with acute lymphoblastic leukemia (ALL). In protocol TCL 842, children with ALL received CrRT 18 Gy in 12 fractions, and 5 concomitant doses of intrathecal methotrexate 15 mg/m2/dose with 15 mg as the maximum, for CNSP after remission achieved. The first IQ test was performed immediately after CNSP. Those who had no CNS relapse for more than 5 years after CNSP had a second IQ test. For children between 3 and 6 years old, the Stanford-Binet (S-B) IV test was used, and for older children, the Wechsler Intelligence Scale for Children-Revised (WISC-R) was used. Fourteen consecutive children at our hospital were enrolled. There were 7 boys and 7 girls. The age at diagnosis ranged from 3 to 9 years old. Two of them were in the high-risk group, eight in the intermediate-risk group, and four in the standard-risk group. The IQ scores of all patients fell within the average range. In the first IQ tests, the mean IQ score was 104.29 (range 83-124, S.D. 14.55). In the second IQ tests, the mean IQ score was 100.93 (range 85-128, S.D. 11.57). Statistically, there was no significant difference between the first and second IQ scores (paired t-test, two-tailed P = 0.4232; one-tailed P = 0.2116). Our findings suggested that CNSP used in protocol TCL 842 did not reduce IQ scores of children with ALL 5 years after CNSP.

Prostate cancer gene therapy: herpes simplex virus thymidine kinase gene transduction followed by ganciclovir in mouse and human prostate cancer models

Prostate cancer is the most common internal malignancy in men in the United States. Most cancers are diagnosed when they are locally advanced or metastatic and there is no effective treatment. In this study we evaluated the effectiveness of cytotoxic gene therapy in human PC-3 and DU145 prostate cancer cell lines and in a rodent cell line, RM-1, derived from the mouse prostate reconstitution model system. The cell lines were efficiently transduced in vitro by a replicative-defective recombinant adenovirus (ADV) carrying the herpes simplex virus thymidine kinase gene (HSV-tk). A virus titer-dependent sensitivity to ganciclovir (GCV) was observed. To determine a target therapeutic viral dose in vivo, subcutaneous tumors were generated by injection of RM-1 cells in syngeneic male hosts and injected with escalating doses of HSV-tk virus (5 x 10(7) to 1 x 10(9) pfu). The mice received GCV twice daily for 6 days and were sacrificed when tumor volumes exceeded 2.5 cm3 or when they appeared to be in distress. Because the two highest doses were equally as effective, further controlled studies were performed with the lower dose of 5 x 10(8) pfu with ADV/RSV-tk or a control virus containing the beta-galactosidase gene (ADV/RSV-beta-Gal) and treated with GCV or saline (PBS). The mean tumor volume in the treated animals was 16% that of control animals at 13 days. Histologically, treated tumors demonstrated necrosis and had a significantly higher apoptotic index. Survival data indicated that the treatment animals lived 7 days (21 in total) longer than the control animals, with 1 treatment animal being totally free of tumor. These results demonstrate that HSV-tk + GCV cytotoxic gene therapy can inhibit the growth of mouse and human prostate cancer cells in vitro and interrupt tumor growth of an aggressive mouse prostate cancer cell line in vivo.

Gastric metaplasia of regenerating duodenal mucosa and deformity of duodenal bulb: a correlative study

The correlation between the presence and degree of gastric metaplasia of regenerating duodenal mucosa and the deformity of duodenal bulb was studied. Based on the endoscopically morphological patterns of bulb, the duodenal ulcers were divided into three types: type I, with a normal-shaped bulb; type II, with mildly deformed bulb; and type III, with a markedly deformed bulb. A total of 159 patients with active duodenal ulcers were scheduled to be treated with H2-receptor antagonists. Of these patients, 124 proved to have a healed duodenal ulcer 4 weeks after initial treatment upon follow-up endoscopic examinations. Two biopsies were taken from the centre of the ulcer scar when the ulcer was found to be healed for light microscopic study. Histologically, the degree of gastric metaplasia was divided into three grades: grades 0, 1 and 2. The results show that a healed duodenal ulcer with a normal-shaped bulb is not frequently accompanied by gastric metaplasia. However, a healed ulcer with a markedly deformed bulb has a high incidence and degree of gastric metaplasia, which may be easily colonized by Helicobacter pylori and thus develop an environment of easy recurrence. Therefore, a cycle of healing and recurrence may exist in patients with a duodenal ulcer and a markedly deformed bulb. Eradication of H. pylori may be the best way to break this cycle.

Neutrophil-mediated suppression of virus replication after herpes simplex virus type 1 infection of the murine cornea

Herpes simplex virus type 1 (HSV-1) infection of the murine cornea induces the rapid infiltration of neutrophils. We investigated whether these cells could influence virus replication. BALB/c mice treated with monoclonal antibody (MAb) RB6-8C5 experienced a profound depletion of neutrophils in the bloodstream, spleen, and cornea. In these animals, virus titers in the eye were significantly higher than those in the immunoglobulin G-treated controls at 3 days postinfection. By day 9, virus was no longer detectable in the controls, whereas titers of 10(3) to 10(6) PFU were still present in the neutrophil-depleted hosts. Furthermore, virus spread more readily to the skin and brains of MAb RB6-8C5-treated animals, rendering them significantly more susceptible to HSV-1-induced blepharitis and encephalitis. Only 25% of the treated animals survived, whereas all of the controls lived. Although MAb RB6-8C5 treatment did not alter the CD4+ T-cell, B-cell, natural killer cell, or macrophage populations, the CD8+ T-cell population was partially reduced. Therefore, the experiments were repeated in severe combined immunodeficiency mice, which lack CD8+ T cells. Again virus growth was found to be significantly elevated in the eyes, trigeminal ganglia, and brains of the MAb RB6-8C5-treated hosts. These results strongly indicate that in both immunocompetent and immunodeficient mice, neutrophils play a significant role in helping to control the replication and spread of HSV-1 after corneal infection.

Determination of thiocyanate anion by high-performance liquid chromatography with fluorimetric detection

A simple and sensitive high-performance liquid chromatographic (HPLC) method was established for the trace determination of thiocyanate anion as a fluorogenic derivative. The method is based on the chemical derivatization of thiocyanate anion with 3-bromomethyl-7-methoxy-1,4-benzoxazin-2-one. The resulting derivative was separated by a Nova-Pak C18 reversed-phase column. Optimization conditions for the derivatization of thiocyanate anion were investigated by HPLC with fluorimetric detection. The linear range for the quantitation of thiocyanate anion was 1-0.05 nmol in 0.1 mL of sample; the detection limit (with a signal-to-noise ratio of 5) of a 20-microL injected aliquot was approximately 3.3 +/- 1.2 fmol. Application of the method to the analysis of thiocyanate anion in saliva and plasma proved to be feasible.

Induction and suppression of renal and hepatic cytochrome P450-dependent monooxygenases by acute and chronic streptozotocin diabetes in hamsters

The acute and chronic effects of streptozotocin diabetes on kidney and liver microsomal monooxygenases were studied using hamsters 2 days and 6 weeks following treatment with the diabetogen, respectively. Acute diabetes increased aniline hydroxylation and N-nitrosodimethylamine demethylation, decreased pentoxyresorufin O-dealkylation, without affecting benzo(a)pyrene hydroxylation and 7-ethoxycoumarin O-deethylation in kidney and liver microsomes. The effects of chronic diabetes on the microsomal monooxygenases were similar to the effects of acute diabetes, except that the chronic diabetic condition markedly decreased benzo(a)pyrene and 7-ethoxycoumarin oxidations in kidney microsomes. Total cytochrome P450 content and NADPH-cytochrome P450 reductase activity in kidney and liver microsomes of the diabetic hamsters were similar to the controls. Gel electrophoresis of microsomes from control and streptozoptocin treated hamster tissues revealed that diabetes enhanced the intensity of protein band(s) in the P450 molecular weight region. Immunoblotting of microsomal proteins showed that acute and chronic streptozotocin diabetes induced proteins immunorelated to P450s 2E1 and 1A in kidney and liver. In marked contrast, the acute and chronic diabetic conditions decreased the level of a P450 2B-immunorelated protein(s) in kidney and liver. The present study demonstrates that acute and chronic streptozotocin diabetes has the ability to induce P450 2E1 and 1A and suppress P450 2B in hamster kidney and liver and that the hamster monooxygenase responds to diabetes differently from the rat enzyme.

Early cytokine synthesis in the excised mouse cornea

Corneas excised from normal BALB/c mice and incubated in vitro were analyzed for the production of "early-warning" cytokines via reverse transcription-polymerase chain reaction and ELISA. It was found that the trauma of excision stimulated rapid IL-1 alpha synthesis, with peak protein accumulation occurring at 6 h, whereas IL-6 synthesis was maximal at 18 h. Neither IL-1 beta protein nor message was detected at any point, and TNF-alpha synthesis never increased above constituted levels. Antibody neutralization of endogenous IL-1 alpha blocked IL-6 synthesis. Addition of exogenous IL-1 alpha induced IL-1 alpha and IL-6 synthesis in vitro. Inoculation of IL-1 alpha into the cornea induced IL-6 synthesis in vivo. Addition of IL-1 alpha could stimulate IL-1R, IL-1 alpha, and IL-6 mRNA synthesis in the epithelial, stromal, and endothelial components of the cornea. However, protein production was readily detected only in the epithelial layer. We concluded that mechanical trauma to the mouse cornea triggers the enhanced synthesis of IL-1 alpha and IL-1R, which in turn results in the production of IL-6 and more IL-1 alpha. That corneal excision did not stimulate the synthesis of IL-1 beta or TNF-alpha indicates that there is a selective induction of early cytokine expression in this specialized tissue.

The Wiskott-Aldrich syndrome and X-linked congenital thrombocytopenia are caused by mutations of the same gene

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, small platelets, eczema, recurrent infections, and immunodeficiency. Besides the classic WAS phenotype, there is a group of patients with congenital X-linked thrombocytopenia (XLT) who have small platelets but only transient eczema, if any, and minimal immune deficiency. Because the gene responsible for WAS has been sequenced, it was possible to correlate the WAS phenotypes with WAS gene mutations. Using a fingerprinting screening technique, we determined the approximate location of the mutation in 13 unrelated WAS patients with mild to severe clinical symptoms. Direct sequence analysis of cDNA and genomic DNA obtained from patient-derived cell lines showed 12 unique mutations distributed throughout the WAS gene, including insertions, deletions, and point mutations resulting in amino acid substitutions, termination, exon skipping, or splicing defects. Of 4 unrelated patients with the XLT phenotype, 3 had missense mutations affecting exon 2 and 1 had a splice-site mutation affecting exon 9. Patients with classic WAS had more complex mutations, resulting in termination codons, frameshift, and early termination. These findings provide direct evidence that XLT and WAS are caused by mutations of the same gene and suggest that severe clinical phenotypes are associated with complex mutations.

Conformation of the propeptide domain of factor IX

The propeptide domain in the precursor forms of blood clotting proteins contains the recognition sequences for gamma-carboxylase. In hemophilia B, several point mutations in this propeptide domain are responsible for the inherited disease. A peptide containing the propeptide sequence of factor IX was synthesized by solid phase methods. Two dimensional 1H-NMR and CD studies indicate that this peptide motif adopts an alpha-helical structure in a 40% trifluoroethanol-containing aqueous solution. The results suggest that the amphipathic alpha-helix within the propeptide domain of factor IX could create a recognition surface for gamma-carboxylase. The influences of mutations and their relationship with the alpha-helical structure are discussed.

Adenovirus-mediated gene therapy in an experimental model of breast cancer metastatic to the brain

We investigated the therapeutic efficacy of adenovirus-mediated gene therapy to treat malignant mammary tumors in vitro and in vivo in the brain. A mammary adenocarcinoma cell line derived from Fischer rats (13762 MAT B III; MAT-B) was used. In vitro studies demonstrated that the MAT-B cells could be efficiently transduced with a replication-defective adenovirus (ADV) vector that carried the herpes simplex virus gene for thymidine kinase (ADV-tk), and that ADV-tk transduction rendered the MAT-B cells sensitive to killing, in a dose-dependent manner, with ganciclovir (GCV). An animal model of a mammary tumor metastatic to the brain was produced by injecting MAT-B cells into the caudate nucleus of Fischer rats. Seven days after MAT-B cell injection, when the tumors were approximately 5 mm2 in cross-sectional size, the tumors were injected with ADV-tk or a control adenovirus vector containing the beta-galactosidase (beta-Gal) gene (ADV-beta gal). After vector injection the animals were treated with GCV or with saline for 6 days. Sixteen days after tumor cell injection, the brains were examined histologically. The rats that were injected with ADV-beta gal and treated with GCV or saline, and those that were injected with ADV-tk and treated with saline had large tumors, whereas the rats that were injected with ADV-tk and treated with GCV had no visible tumor tissue at the site of tumor cell injection. In survival studies animals treated with ADV-tk+GCV survived a significantly longer time than animals treated with ADV-beta gal+GCV. Our results demonstrate that the recombinant adenoviral vector containing the tk gene confers GCV cytotoxic sensitivity to mammary tumor cells in vitro and in the brain, and suggest that this treatment strategy may be useful in treating somatic tumors that metastasize to the brain.

Stability and pharmacokinetic studies of a new immunosuppressant, mycophenolate mofetil (RS-61443), in rats

Mycophenolate mofetil (MPM), a new immunosuppressant, is a morpholinoethyl ester of mycophenolic acid (MPA). The enzymatic and non-enzymatic hydrolysis was studied in an artificial digestive fluid, rat plasma, and tissue homogenates. MPM was chemically stable in the artificial digestive fluid. In rat tissue homogenates and plasma, MPM was rapidly hydrolysed to MPA. The conversion rate of MPM to MPA in various rat tissue homogenates was in the order of liver > kidney > plasma > small-intestine epithelial cells. After the intravenous injection of MPM at 16.7 mg kg-1, the terminal elimination half-life, t1/2 beta, was 4.74 +/- 0.33 (mean +/- SD)h, and the area under the plasma concentration versus time curve, AUC, was 48.78 +/- 6.01 micrograms h mL-1. After intraduodenal (ID) administration of MPM at 16.7 mg kg-1, t1/2 beta was 3.92 +/- 1.05 h, and the AUC was 38.08 +/- 8.30 micrograms h mL-1. The systemic availability of MPA after ID MPM dosing was 1.52 times higher than that after ID administration of MPA. This result supports the usefulness of MPM as an oral prodrug of MPA as a new oral immunosuppressant.

Adenovirus-mediated gene therapy for experimental spinal cord tumors: tumoricidal efficacy and functional outcome

We evaluated the efficacy of adenoviral-mediated gene therapy of experimental spinal cord tumors and the functional outcome after this treatment. Spinal cord tumors were generated in the thoracic region of the spinal cord in Fischer 344 rats by stereotaxic intramedullary injection of 1 x 10(4) 9L gliosarcoma cells. Seven days after tumor cell injection, a replication-defective adenoviral vector carrying the herpes simplex virus thymidine kinase gene (ADV-tk) or a control adenoviral vector carrying the beta-galactosidase gene (ADV-beta gal) was injected into the tumors. Beginning 12 h later the animals were treated with the antiviral drug ganciclovir (GCV; 50 mg/kg) or saline twice a day for 6 days. The neurological performance of the animals was assessed during and following treatment. Eighteen days after tumor cell injection, all of the control animals had paraplegia and large tumors. In contrast, no tumors were detected in animals treated with ADV-tk and GCV. In long-term studies, two of the 5 animals treated with ADV-tk and GCV remained tumor-free and remained neurologically intact at 6 months whereas all animals in the control groups became paraplegic within 18 days.

RU486 inhibits ovulation, fertilization and early embryonic development in rabbits: in vivo and in vitro studies

OBJECTIVE

To clarify the role of P in ovulation, fertilization, and early embryonic development using RU486, a potent P receptor blocker.

DESIGN

Ovulatory efficiency, IVF, and early embryonic development were evaluated after RU486 administration in vivo and in vitro.

SETTING

Research laboratory of a university hospital.

PARTICIPANTS

Mature male and female New Zealand white rabbits.

INTERVENTIONS

Animals were treated with RU486 or vehicle for 3 days before hCG-induced ovulation. Ovaries treated with hCG to induce ovulation were perfused for 6 hours in vitro with RU486 or vehicle. In vitro fertilization was performed in the presence or absence of RU486.

MAIN OUTCOME MEASURES

The percentage of mature follicles ovulating (ovulatory efficiency) was determined after in vivo and in vitro treatment. Fertilization, morula, and blastocyst development were evaluated every 24 hours for 120 hours.

RESULTS

RU486 significantly inhibited ovulation, fertilization, and early embryonic development.

CONCLUSIONS

Progesterone plays a significant role in ovulation, fertilization, and preimplantation embryonic development.

Gene expression of markers associated with proliferation and differentiation in human keratinocytes cultured from epidermis and from buccal mucosa

Normal keratinocytes from epidermis and from buccal mucosa underwent dissimilar stages of differentiation in the same culture medium and responded differently to changes in the composition of the medium. Manifestations of these variations were examined in terms of the expression at the mRNA level (as measured by reverse transcriptase-polymerase chain reaction) of three regulatory genes (cdc2, c-myc, and p53) and five that encode structural proteins (keratins K5, K10 and K13, involucrin, and filaggrin), in three growth-medium formulations. The culture conditions enhanced or retarded maturation; the observed alterations in gene expression correlated with these changes. Except for the proliferation genes, the non-keratinizing buccal mucosa generally responded more weakly than the orthokeratotic epidermis to culture-medium supplementation favouring differentiation. Gene expression in cultured keratinocytes reflected their ability to differentiate in vivo; genes were expressed even when the corresponding protein was not seen in vitro. Although keratin K10 is not prevalent in the buccal mucosa nor keratin K13 in the epidermis, the genes for both were found to be expressed in both tissues.

Effects of the benzodiazepine inverse agonist RO19-4603 on the maintenance of tolerance to a single dose of ethanol

The time course of the novel benzodiazepine inverse agonist, RO19--4603 (0.075 or 0.150 mg/kg) in antagonizing the depressant effects of ethanol (EtOH) (0.50, 1.0 and 1.5 g/kg) and the development of tolerance on locomotor behaviors (e.g., ambulatory count, total distance and stereotypy count) were investigated in Sprague-Dawley rats given EtOH injections spaced at 24-hr intervals. A single dose of RO19--4603 prevented the development of tolerance to the 0.50- and 1.0-g/kg EtOH doses 24-hr post-RO19--4603 administration on most locomotor behaviors. On Day 1, the 0.150-mg/kg RO19--4603 dose prevented the reduction of motor behaviors after the 1.0- and 1.5-g/kg EtOH doses, whereas the 0.075-mg/kg RO19--4603 dose prevented the reduction of motor behaviors only after the 1.5-g/kg EtOH dose. The 0.075- and 0.150-mg/kg RO19--4603 doses also prevented the EtOH-induced reduction of motor behaviors after the 1.5-g/kg EtOH dose 24-hr post-RO19--4603 administration. RO19--4603 was without effect on activity when given alone. These data suggest that the motor impairing effects of EtOH and the development of tolerance to them may involve gamma-aminobutyric acidA-benzodiazepine receptor mechanisms that when occupied, even briefly by certain benzodiazepine inverse agonists, produce long-lasting effects on locomotion and tolerance.