Molar enthalpy and molar volume of methylene and benzene homologues in reversed-phase liquid chromatography

In this study, thermodynamic properties are measured for methylene and benzene homologues in reversed-phase liquid chromatography using octadecylsilica stationary phases and methanol mobile phase. The change in molar enthalpy (delta H degree) is determined from graphs of the logarithm of the capacity factor versus the inverse temperature (15 to 60 degrees C), whereas the change in molar volume (delta V degrees) is determined from graphs of the logarithm of the capacity factor versus pressure (830 to 5000 p.s.i.). For octadecylsilica phases with low bonding density (2.7 mumol m-2), delta H degree and delta V degree are small and are relatively unaffected by temperature and pressure. These thermodynamic parameters are linearly related to the homologue number for the methylene homologues, but not for the benzene homologues. For the ethylene group, delta delta H degree and delta delta V degree are in the order of -0.41 kcal mol-1 and -1.0 cm3 mol-1, respectively, at 30 degrees C. As the bonding density increases (5.4 mumol m-2), the molar volume and molar enthalpy decrease in a significant and nonlinear manner with the homologue number. Moreover, these thermodynamic parameters are markedly affected by temperature and pressure. For the ethylene group, delta delta H degree and delta delta V degree are in the order of -3.65 kcal mol-1 and -14.1 cm3 mol-1, respectively, at 30 degrees C. The theoretical and practical implications of these measurements are discussed with respect to the retention mechanism in reversed-phase liquid chromatography.

Adenovirus-mediated suicide gene therapy for experimental bladder cancer

OBJECTIVES

To determine the feasibility, safety, and efficacy of suicide gene therapy using adenoviral-mediated herpes simplex virus thymidine kinase gene (HSV-tk) and the prodrug ganciclovir (GCV) in a murine model of human transitional cell carcinoma.

METHODS

We used a replication-defective adenoviral construct containing the beta-galactosidase gene (ADV/Rous sarcoma virus [RSV]-beta-gal) as a control or ADV/RSV-tk as the therapeutic vector under the transcriptional control of the RSV long-terminal repeat promoter. Transduction efficiency was assessed in vitro by infection of MBT-2 cells with ADV/RSV-beta-gal at various multiplicities of infection (MOI) utilizing 5-bromo-4-chlor-3-indolyl-beta-D-galactoside (X-gal) staining. Sensitivity of MBT-2 cells to the therapeutic vector was determined after infection with ADV/RSV-tk with or without GCV. Subcutaneous tumors were established in syngeneic C3H/He female mice with 5 x 10(5) MBT-2 cells. Optimal dosing of ADV/RSV-tk was determined by direct percutaneous tumor injection with increasing viral doses and treatment with GCV. Treatment efficacy, long-term survival, and toxicity were determined in separate, similar, controlled experiments.

RESULTS

In vitro studies indicated greater than 95% transduction 96 hours after inoculation at an MOI of 3000 and a greater than 95% cell death rate with RSV-tk + GCV at an MOI of 61 or greater. In vivo experiments demonstrated an optimal viral dose of 3 x 10(8) plaque-forming units (pfu) and a greater than fourfold reduction in tumor growth for the animals treated with ADV/RSV-tk compared with control animals (P = 0.0013). Toxicity was limited to histologic evidence of hepatitis with ADV/RSV-tk doses greater than 3 x 10(8) pfu + GCV. Long-term survival of treatment animals was significantly increased over that of control animals (59%, P = 0.0001).

CONCLUSIONS

ADV/RSV-tk with GCV treatment results in efficient gene transfer in vitro and provides effective therapy in experimental murine bladder cancer by significantly inhibiting tumor growth and improving host survival.

The role of insulin-like growth factor-I (IGF-I) and estradiol in rabbit corpus luteum progesterone production

To determine whether insulin-like growth factor-I (IGF-I) plays a role in rabbit corpus luteum (CL) physiology the authors examined: IGF-I expression, the effect of IGF-I on progesterone (P) production in vitro, and the interaction of IGF-I with estradiol, the primary luteotropin in the rabbit. Northern blot analysis revealed that IGF-I mRNA is present in the rabbit CL throughout pseudopregnanacy. An intact ovarian in vitro perfusion model and dispersed luteal cell culture were used to determine effects of IGF-I on P production and interactions with estradiol. IGF-I significantly stimulated P production compared to control medium by the isolated, intact perfused rabbit ovary and by dispersed, cultured luteal cells. Estradiol alone did not stimulate P production in vitro. Estradiol did augment IGF-I stimulated P production in the intact perfused ovary and in luteal cell culture. These findings support a role for IGF-I in rabbit CL P production.

[Different susceptibilities to desensitization of three alpha 1-adrenoceptor subtypes induced by sustained norepinephrine stimulation]

cDNAs for the bovine alpha 1A-, hamster alpha 1B- and rat alpha 1D-adrenoceptors (AR) were transfected into human embryonic kidney 293 (HEK293) cells by calcium phosphate precipitation and stably expressed at high levels. The inositol phosphates (InsPs) accumulation was measured by the method of 3H-inositol incorporation and column chromatography. Susceptibilities to the desensitization of alpha 1-AR subtypes-mediated InsPs accumulation were determined in HEK 293 cells stimulated sustainedly by norepinephrine (NE). The NE-induced InsPs accumulation showed progressive decrease by NE pretreatment with increasing time of preincubation and concentration of NE in the cells transfected with all the alpha 1-AR subtypes. However, susceptibilities to the desensitization were different among the three subtypes. The desensitization of alpha 1A-AR took place earliest and needed lowest concentration of NE. The desensitization of alpha 1D-AR appeared to be the latest and needed hightest concentration of NE, while alpha 1B-AR stood in between.

Adenovirus-mediated herpes simplex virus thymidine kinase gene and ganciclovir therapy leads to systemic activity against spontaneous and induced metastasis in an orthotopic mouse model of prostate cancer

It is critical to develop new therapies, such as gene therapy, which can impact on both local and metastatic prostate cancer progression. We have developed an orthotopic mouse model of metastatic prostate cancer using a cell line (RM-1) derived from the mouse prostate reconstitution (MPR) model system. This mouse model closely simulates the anatomical and biological milieu of the prostate and allows for realistic testing of experimental gene therapy protocols. Adenovirus (ADV)-mediated transduction of the herpes simplex virus thymidine kinase (HSV-tk) gene in conjunction with ganciclovir (GCV) in this model led to significant suppression of growth and of spontaneous metastasis at 14 days post-tumor inoculation. Longer-term studies produced a significant survival advantage and a continued suppression of metastatic activity for treatment animals despite regrowth of the primary tumor. Challenge by injection of tumor cells into the tail vein following excision of treated and control s.c. primary tumors resulted in 40% reduction in lung colonization in the treatment group, indicating the possible production of systemic anti-metastatic activity following a single in situ treatment with ADV/HSV-tk + GCV in this model system.

Organization of the human beta-1,2-N-acetylglucosaminyltransferase I gene (MGAT1), which controls complex and hybrid N-glycan synthesis

UDP-GlcNAc: alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (EC 2.4.1.101; GlcNAc-T I) is a medial-Golgi enzyme which catalyses the first step in the conversion of oligomannose-type to N-acetyl-lactosamine- and hybrid-type N-glycans and is essential for normal embryogenesis in the mouse. Previous work indicated the presence of at least two exons in the human GlcNAc-T I gene MGAT1, exon 2 containing part of the 5' untranslated region and the complete coding and 3' untranslated regions, and exon 1 with the remainder of the 5' untranslated region. We now report the cloning and sequencing of a human genomic DNA fragment containing exon 1, which is between 5.6 and 15 kb upstream of exon 2. Transient transfection, ribonuclease protection and reverse transcriptase-mediated PCR indicated the absence of transcription start sites in intron 1 between exons 1 and 2. Northern analysis, ribonuclease protection, primer extension analysis and rapid amplification of 5'-cDNA ends showed that there are multiple transcription start sites for exon 1 compatible with the expression by several human cell lines and tissues of two transcripts, a broad band ranging in size from 2.7 to 3.0 kb and a sharper band at 3.1 kb. The 5' flanking region of exon 1 has a GC content of 81% and has no canonical TATA or CCAAT boxes but contains potential binding sites for transcription factors Sp1, GC-binding factor and epidermal growth factor receptor-specific transcription factor. Chloramphenicol acetyltransferase (CAT) expression was observed on transient transfection into HeLa cells of a fusion construct containing the gene for CAT and a genomic DNA fragment from the 5' flanking region of exon 1. It is concluded that MGAT1 is a typical housekeeping gene although there is, in addition, tissue-specific expression of the larger 3.1 kb transcript.

Metacarpal hand: classification and guidelines for microsurgical reconstruction with toe transfers

Metacarpal hand refers to the hand that has lost its prehensile ability through amputation of all fingers with or without amputation of the thumb. Functional restoration can be achieved by a wide variety of microvascular toe transfer techniques. When deciding which procedure should be used, careful consideration must be given to the level of amputation of the fingers as well as the functional status of the remaining thumb. In this article we propose a classification for the various patterns of the metacarpal hand along with guidelines for selection of the proper toe transfer procedure.

CD8+ T-cell-mediated suppression of HIV replication in the first year of life: association with lower viral load and favorable early survival

OBJECTIVE AND DESIGN

To study the role and development of non-cytotoxic CD8+ T-cell-mediated suppression of HIV replication in early perinatal HIV infection in a prospective study of vertically infected infants. CD8 T-cell-mediated HIV suppression was measured several times during the first year of life and correlated with viral load, cytotoxic T-cell (CTL) activity, in vitro antibody production (IVAP) and clinical outcome.

METHODS

CD8+ T-cell-mediated HIV suppression was measured by comparing the amount of p24 antigen produced by endogenously infected lymphocytes with cultures of the same number of autologous CD4+ T cells from which CD8+ cells were removed immunomagnetically. CD8 viral suppressive activity (VSA) was defined as a > or = 50% reduction in p24 antigen in the cultures containing CD8+ cells.

RESULTS

CD8+ T-cell-mediated HIV VSA was detected in 11/16 infants in the first year of life, including six/nine infants studied before 6 months and as early as 3 weeks of age. Infants who demonstrated CD8 VSA had a lower early peak and 6-month 'setpoint' plasma HIV RNA concentration than infants who lacked CD8 VSA [1.51 versus 4.94 and 0.094 versus 0.639 x 10(6) copies/ml, respectively, and higher CD4 percentage at 1 year of age. Survival of infants lacking CD8 VSA (four/six were rapid progressors) was shorter than for infants who demonstrated CD8 VSA (none out of 10 were rapid progressors). CD8 VSA was present before CTL and before or at the same time as IVAP in two of two and 11 of 14 infants studied, respectively.

CONCLUSIONS

CD8+ T-cell-mediated VSA can be demonstrated in a large proportion of HIV-infected infants early in the course of infection. This non-cytolytic HIV-suppressive immune response appears to play an important protective role in the early control of perinatal HIV infection at a time when other immune responses are either absent or deficient.

Out-patient surgery for the correction of penile curvature

OBJECTIVE

To evaluate an outpatient anaesthetic and surgical procedure for the correction of curvature of the penis.

PATIENTS AND METHODS

From February 1993 to December 1995, 128 patients (mean age 31 years, range 14-67) with penile curvature (120 with congenital curvature and eight with penile deformity from Peyronie's disease) were treated as out-patients at our institution using a proximal dorsal nerve block and ventral infiltration of the penis as the method of anaesthesia. The degree of deformity, pain and sexual activity were assessed before and after surgery and all patients were followed post-operatively using a questionnaire to determine the outcome and their satisfaction.

RESULTS

All the patients were able to leave the hospital shortly after surgery. The follow-up period ranged from 4 to 35 months (mean 17.3); 112 patients (87.5%) reported a satisfactory cosmetic and functional result, while the other 16 patients reported an improvement but had inadequate correction. There were no significant short- or long-term complications; three patients with diabetes developed a hard lump over the operated tunica.

CONCLUSIONS

This unique operative method provided excellent correction of the deformities, was safe, cost-efficient and durable and could be performed as an out-patient procedure.

Vascularized toe joint transfer to the hand

From 1984 to 1993, 36 vascularized toe joints were transferred in 33 patients. The present study group excludes 3 toe joint transfers to elbow and temporomandibular joints and 4 toe joint to hand transfers lost to follow-up. The final study group includes 29 vascularized toe joint transfers in 27 patients, 21 males and 6 females. All were performed for posttraumatic reconstruction, except one transfer for congenital deformity. Follow-up averaged 32.4 months. Mean range of motion was 34 degrees in toe metatarsophalangeal joint to hand metacarpophalangeal joint transfers, 32 degrees in toe proximal interphalangeal joint to hand metacarpophalangeal joint transfers, and 24 degrees in toe proximal interphalangeal joint to hand proximal interphalangeal joint transfers. Although vascularized toe joint transfer is an alternative to arthrodesis, in order to have a greater range of motion than average, the patient must have well-functioning muscle and associated tendons effecting joint motion. Good results were obtained in two immediate free vascularized toe joint transfers to complex injuries involving loss of the metacarpophalangeal joint. We encourage toe joint transfer in selected complex hand injuries.

Voice range profile of Taiwanese normal young adults: a preliminary study

BACKGROUND

This project investigated the physiological frequency range of phonation and the maximum range of speaking fundamental frequency of Taiwanese normal young adults as the clinical diagnostic criteria for voice populations in Taiwan. The physiological frequency range of phonation, and the maximum range of speaking fundamental frequency, are important indicators of vocal function; both can be expanded after vocal training. If a tonal language, Mandarin, is regarded as a daily pitch exercise, the physiological frequency range of phonation and the maximum range of speaking fundamental frequency of native Mandarin speakers could be greater than those of non-tonal language speakers. Thus it is inaccurate to use voice data of non-tonal language speakers as a reference for native Mandarin speakers in Taiwan.

METHODS

This study determined the physiological frequency range of phonation and the sound pressure level of softest and loudest phonation over the entire fundamental frequency range of a voice, and the maximum range of speaking fundamental frequency in reading passage produced by native Mandarin speakers of normal young adults in Taiwan.

RESULTS

The result revealed that in reading female native Mandarin speakers in Taiwan have a significantly higher mean speaking fundamental frequency, higher mean highest speaking fundamental frequency and larger maximum range of speaking fundamental frequency than male native Mandarin speakers. In vocal range profile, female native Mandarin speakers showed significantly higher mean highest tone and higher mean lowest tone than male native Mandarin speakers. The physiological frequency range of phonation in voice-range-profile for both sexes exceeded three octaves.

CONCLUSIONS

The differences of pitch data between the female and male groups can be explained by the larger amplitude of vocal fold vibration for males resulting in lower fundamental frequency, and the more emotional voice used by female speakers when reading resulted in a larger maximum range of speaking fundamental frequency. The data obtained in this study can be applied clinically to voice populations as a diagnostic tool of vocal function for Mandarin speakers.

Gene therapy for hepatocellular carcinoma: long-term remission of primary and metastatic tumors in mice by interleukin-2 gene therapy in vivo

To explore gene therapy as a new treatment modality for hepatocellular carcinoma, a pre-clinical animal model was established by intrahepatic implantation of a mouse hepatocellular carcinoma cell line (MH134) in syngeneic recipients. The resulting hepatic tumors were treated with a recombinant adenoviral vector expressing the murine interleukin-2 (IL-2) gene, and long-term remission was achieved in 50% of the animals. The remaining animals died of malignant ascites, which also occurs in some human patients. Those animals were treated with a second dose of the recombinant adenoviral vector by direct inoculation into the peritoneal cavity, and long-term remission of the disseminated disease was achieved in 55% of the animals. Thus, a combined cure rate of greater than 75% for primary- and disseminated hepatocellular carcinoma was achieved by successive adenovirus-mediated IL-2 gene treatments. Histopathological and immunocytochemical analyses showed massive infiltration of the tumor by macrophages and T lymphocytes in IL-2 vector treated animals. The surviving animals developed systemic antitumoral cellular immunity that protected them against challenges of parental hepatoma cells implanted at distant sites. The results suggest that IL-2 gene therapy may be a strategy applicable for the treatment of both primary and metastatic hepatocellular carcinomas in man.

Ubiquitin-proteasome pathway mediates intracellular degradation of apolipoprotein B

Newly synthesized apolipoprotein B (apoB) is degraded by a proteolytic process in the pre-Golgi compartment that can be inhibited by N-acetyl-L-leucinyl-L-leucinyl-L-norleucinal (ALLN) but not by several other protease inhibitors. We have tested the hypothesis that the ubiquitin-proteasome pathway is involved in the intracellular degradation of apoB in liver cells. We found that inhibitors of proteasomes blocked the degradation of apoB in cultured human hepatoma (HepG2) cells. Protein degradation by proteasomes is ATP-dependent, and ATP depletion by dinitrophenol and 2-deoxyglucose also inhibited apoB degradation in these cells. Furthermore, the intracellular human apoB isolated by immunoprecipitation was shown to react specifically with anti-ubiquitin antibody by immunoblotting. This result was corroborated by sequential immunoprecipitation of [35S]methionine-labeled proteins by anti-human apoB and anti-ubiquitin antisera. In contrast, secreted apoB was not ubiquitinated. The amount of intracellular ubiquitinated apoB was increased by the proteasome inhibitors, ALLN and carbobenzoxyl-leucinyl-leucinyl-norvalinal-H (MG115). Our findings suggest that the ubiquitin-proteasome pathway is one mechanism for the intracellular degradation of apoB.

Adenovirus-mediated interleukin-12 gene therapy for metastatic colon carcinoma

Recombinant adenoviral mediated delivery of suicide and cytokine genes has been investigated as a treatment for hepatic metastases of colon carcinoma in mice. Liver tumors were established by intrahepatic implantation of a poorly immunogenic colon carcinoma cell line (MCA-26), which is syngeneic in BALB/c mice. Intratumoral transfer of the herpes simplex virus type 1 thymidine kinase (HSV-tk) and the murine interleukin (mIL)-2 genes resulted in substantial hepatic tumor regression, induced an effective systemic antitumoral immunity in the host and prolonged the median survival time of the treated animals from 22 to 35 days. The antitumoral immunity declined gradually, which led to tumor recurrence over time. A recombinant adenovirus expressing the mIL-12 gene was constructed and tested in the MCA-26 tumor model. Intratumoral administration of this cytokine vector alone increased significantly survival time of the animals with 25% of the treated animals still living over 70 days. These data indicate that local expression of IL-12 may also be an attractive treatment strategy for metastatic colon carcinoma.

Optical monitoring of silver-based transparent heat mirrors

Both three-layer (TiO(2)-Ag-TiO(2)) and five-layer (TiO(2)-Ag-TiO(2)-Ag-TiO(2)) heat mirrors with optimum transmission in the visible and good reflectance in the IR have been designed by admittance diagram techniques. The mirrors were fabricated successfully by optical monitoring. An interesting anomalous layer was found and explained, and its equivalent refractive index and thickness are 2.015 - i0.016 and 2.56 nm, respectively.

Adenoviral-mediated suicide gene therapy for hepatic metastases of breast cancer

Metastases of breast cancer are a major cause of treatment failure. To evaluate the therapeutic efficacy of suicide gene therapy in metastatic breast cancer, we used the herpes simplex virus thymidine kinase (HSV-tk) gene followed by ganciclovir (GCV) administration to treat breast cancer, generated by an adenocarcinoma cell line MOD in syngeneic mice. The bystander effect of HSV-tk + GCV on tumor cell killing was illustrated by demonstrating complete regression of subcutaneous tumors consisting of 90% parental tumor cells and 10% HSV-tk transformed tumor cells. To establish a model of breast cancer metastases in the liver, tumors were generated by intra-hepatic implantation of MOD cells in syngeneic animals. Two weeks after tumor cell implantation, replication defective adenoviral vectors expressing HSV-tk (ADV.tk), or beta-galactosidease (ADV. beta-Gal) were injected intratumorally, followed by buffer or GCV administration. Treatment with ADV.tk + GCV resulted in significant regression of tumor (P < .001), as assessed by computerized morphometric analysis of residual tumor. This was reflected as a significant prolongation of survival in treated animals (P < .001). These results demonstrate that ADV-mediated suicide gene therapy in vivo can be incorporated in a comprehensive treatment strategy for liver metastases of breast cancer.

Combination suicide and cytokine gene therapy for hepatic metastases of colon carcinoma: sustained antitumor immunity prolongs animal survival

The effectiveness of combination therapy using a suicide gene and cytokine genes for the treatment of metastatic colon carcinoma in the mouse liver was investigated. Pre-established hepatic tumors treated with a recombinant adenoviral vector containing the herpes simplex virus thymidine kinase gene(tk) exhibited substantial regression, although all treated animals suffered from subsequent relapses. Although cotreatment with a mouse interleukin 2 (mIL-2)-containing adenoviral vector induced an effective antitumor immune response, the immunity waned with time, and the treated animals eventually succumbed to hepatic tumor relapse or distant metastases. In this study, mouse granulocyte macrophage colony-stimulating factor (mGM-CSF) gene was tested for its ability to further enhance and prolong the antitumoral cellular immunity. A fraction of the animals treated with tk + mIL-2 + mGM-CSF developed long-term antitumor immunity and survived for more than 4 months without recurrence. This long-term antitumor immunity could be enhanced further by subsequent "vaccination" with mIL-2-expressing parental tumor cells. The results indicate that local expression of GM-CSF in the hepatic tumors and prolonged mIL-2 expression are necessary to generate persistent antitumor immunity that is essential for the prevention of tumor recurrence and long-term animal survival.

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.