[Hepatic arterial infusion of 32P-radionuclide microspheres for radiation therapy of hepatocellular carcinoma]

OBJECTIVE

To investigate the efficacy of internal radiation of (32)P-glass microspheres ((32)P-GMS) in unresected hepatocellular carcinoma (HCC) via subcutaneous arterial port.

METHODS

Hepatic arterial (99)technetium-macroaggregate albumin ((99)Tc-MAA) scanning via subcutaneous arterial port was undertaken to measure lung/liver shunting ratio and tumor/liver ratio. Hepatic arterial infusion of (32)P-GMS was performed in 17 cases of HCC with a dose from 1.11 to 1.30 GBq. Twenty cases of HCC undergoing hepatic arterial chemoembolization (HACE) in the same period served as controls group.

RESULTS

There was no treatment-related death in the 17 cases. In 7 of the 17 cases, AFP level and/or tumor size decreased by 50% after treatment, with a response rate of 64.7%. The median survival time was 5.5 months, and the 3-, 6-, 9-, 12-month survival rates were 94.1%, 44.1%, 31.0%, 24.4%, respectively. The therapeutic efficacy was better than that of HACE. The survival time was significantly longer in patients with T/N ratio >or= 2 than in those with T/N < 2 (P < 0.05).

CONCLUSIONS

Hepatic arterial infusion of (32)P-GMS is an alternative treatment for unresected HCC.

Insect larval expression process is optimized by generating fusions with green fluorescent protein

The insect larvae/baculovirus protein production process was dramatically simplified by expressing fusion proteins containing green fluorescent protein (GFP) and the product-of-interest. In this case, human interleukin-2 (hIL-2) and chloramphenicol acetyl-transferase (CAT) were model products. Specifically, our fusion construct was comprised of a histidine affinity ligand for simplified purification using immobilized metal affinity chromatography (IMAC), the UV-optimized GFP (GFPuv) as a marker, an enterokinase cleavage site for recovery of the product from the fusion, and the product, hIL-2 or CAT. Both the approximately 52 kDa GFPuv/hIL-2 and approximately 63 kDa GFPuv/CAT fusions were expressed in Trichoplusia ni larvae at 9.0 microg-hIL-2 and 24.1 microg-CAT per larva, respectively. The GFP enabled clear identification of the infection process, harvest time, and more importantly, the quantity of product protein. Because the GFP served as a marker, this technique obviates the need for in-process Western analyses (during expression, separation, and purification stages). As a purification marker, GFP facilitated rapid identification of product-containing elution fractions (Cha et al., 1999b), as well as product-containing waste fractions (e.g., cell pellet). Also, because the fluorescence intensity was linear with hIL-2 and CAT, we were able to select the highest-producing larvae. That is, three fold more product was found in the brightest larva compared to the average. Finally, because the GFP is attached to the product protein and the producing larvae can be selected, the infection and production processes can be made semi-continuous or continuous, replacing the current batch process. These advantages should help to enable commercialization of larvae as expression hosts.

Monitoring GFP-operon fusion protein expression during high cell density cultivation of Escherichia coli using an on-line optical sensor

Synthesis of an operon fusion protein was investigated in batch and fed-batch cultures at high cell densities of recombinant Escherichia coli JM105 [pBAD-GFP::CAT]. Glucose-limited growth was achieved without accumulation of inhibitory byproducts allowing high cell densities (110 g L(-1) DCW) to be attained. This was believed to be the highest reported value for dry cell mass of E. coli strain JM105 expressing two recombinant proteins. Transcription of the two reporter genes, green fluorescent protein (GFP) and chloramphenicol acetyltransferase (CAT), was under the control of the p(BAD) promoter of the araBAD (arabinose) operon. Each protein was independently translated via separate ribosome binding sites. CAT served as a model recombinant protein product to illustrate the noninvasive quantitative reporting ability of GFP during high cell density fermentations. Expression of GFP was monitored on-line using an intensity-based optical sensor. A linear correlation between the on-line GFP intensity and the enzymatic activity of CAT allowed for in vivo real-time quantitative monitoring of a fermentation product under conditions of high biomass concentration and high productivity.

Diagnostic yield of screening for type 2 diabetes in high-risk patients: a systematic review

OBJECTIVE

To determine the value of using risk factors to decide which patients should undergo serum screening for type 2 diabetes.

SEARCH STRATEGIES

The MEDLINE and EMBASE electronic databases were searched for original studies of screening for type 2 diabetes on the basis of risk factors. The reference lists of all reviews, letters, editorials, consensus statements, and guidelines for diabetes screening were searched for additional studies. The Cochrane database was also searched for relevant reviews.

SELECTION CRITERIA

All original studies regarding selective serum screening for type 2 diabetes on the basis of risk factors were included. review. Three studies were cross-sectional in design; 3 employed survey data to develop computerized statistical models that used risk factors to identify cases of type 2 diabetes; and 1 used a similar method, but the resulting model was field tested in a separate population. No study describes a risk-factor-based method or instrument that helps substantially in the diagnosis of type 2 diabetes.

CONCLUSIONS

Selective screening for type 2 diabetes on the basis of risk factors cannot be recommended. Serum screening can be offered to patients who present with typical symptoms of diabetes.

Polarization-based sensing of glucose using an oriented reference film

We describe a new approach to glucose sensing using polarization measurements in the presence of a stretch-oriented reference film. The method relies on measurement of the polarized emission from the reference film and of a fluorophore which changes intensity in response to glucose. A glucose-sensitive fluorescent signal was provided by the glucose/galactose binding protein from E. coli. This protein was labeled with an environmentally sensitive fluorophore at a single genetically inserted cysteine residue, and displayed decreased fluorescence upon glucose binding. Using the protein and the reference film we observed glucose-sensitive polarization values for micromolar glucose concentrations. This method of polarization-based sensing is generic and can be used for any sensing fluorophore which displays a change in intensity. In principle, one can construct simple and economical devices for this type of glucose measurement. © 1999 Society of Photo-Optical Instrumentation Engineers.

Interaction between gene p53 and oncogene mdm2 in human glandular lung cancer cell line GLC-82

OBJECTIVE

To study the interaction between oncogene mdm2 and wp53 in human glandular lung cancer cell line GLC-82.

METHODS

By lipofectamine-mediated DNA transfection, wp53 and mdm2 were transfected separately or co-transfected into GLC-82 cells via retrovival vector pDOR-neo, a carrier of wp53 and mdm2.

RESULTS

The growth of GLC-82 cells was blocked and their DNA synthesis inhibited by wp53, its colony-forming rate in soft agar culture and the tumorigenicity in nude mice declined and mdm2 antagonized the function of wp53.

CONCLUSION

After the recombinant vector pDOR-mdm2 was transfected into GLC-82 cells containing wp53, mdm2 partially deprives wp53 of its function of inhibiting the growth of GLC-82 cells.

Polarization-based oxygen sensor

A new approach to oxygen sensing based on the luminescence polarization observed from a novel type of sensor is described. The oxygen sensor consists of an oxygen-sensitive silicone film containing tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) chloride [Ru(dpp)3Cl2] and an oxygen-insensitive film of Styryl 7 in poly(vinyl alcohol). Polarizers are used to select orthogonally polarized emission components from Ru(dpp)3Cl2 and Styryl 7. The polarization of the combined emission was found to be highly sensitive to the partial pressure of oxygen. This method of polarization sensing is generic and can be used with any fluorophore which displays an analyte-dependent change in intensity.

Modeling the response time of an in vivo glucose affinity sensor

A mathematical model was developed to describe the dose-response relationship of an optical glucose sensor. The basis for glucose detection is the reversible competitive displacement of a ligand from a receptor protein with specific binding sites for certain carbohydrates. Detection of glucose is based on measurements of the change in fluorescent lifetime of the donor-labeled protein, as it binds to the acceptor-labeled ligand. The sensor was modeled as a hollow fiber membrane, permeable to glucose, which encapsulates a solution of the receptor protein and competing ligand. Model equations that describe the diffusion of glucose through the fiber membrane and the subsequent displacement reactions within the fiber lumen were solved numerically to predict the response time of the sensor following a step change in bulk glucose concentration. The incorporation of an external mass transfer boundary layer was found to increase the response time by a factor of 3.7 over the well-stirred case. On the basis of the results of a parametric study, the response time of the sensor was found to be most sensitive to the diffusion coefficient of glucose in the membrane. When compared to experimental response times for an intensity-based affinity sensor using Concanavalin A as the receptor protein and dextran as the competing ligand, the model predictions were found to be significantly shorter than those observed. The effect of the in vivo environment on the performance of the sensor was also investigated through the incorporation of a fibrotic capsule layer. The additional diffusional resistance offered by the capsular tissue resulted in a 5-fold increase in the response time of the sensor.

Chromoblastomycosis masquerading as palmo-plantar psoriasis

A 8-year-old boy presented with scaly plaques of both soles and left palm of 4 year duration. The plaques were well defined scaly, fissured and hyperkeratotic resembling palmo-plantar psoriasis. KOH preparation of the scrapings revealed round, brown, thickwalled bodies with planate division. Grey black, velvety folded colonies were seen in culutre on Sabouraud's dextrose agar. Lacto phenol cotton blue preparation revealed Fonsecaea pedrosoi as the cause of chromoblastomycosis.

Green fluorescent protein as a noninvasive stress probe in resting Escherichia coli cells

We constructed and characterized three stress probe plasmids which utilize a green fluorescent protein as a noninvasive reporter in order to elucidate Escherichia coli cellular stress responses in quiescent or resting cells. Cellular stress levels were easily detected by fusing three heat shock stress protein promoter elements, those of the heat shock transcription factor sigma32, the protease subunit ClpB, and the chaperone DnaK, to the reporter gene gfpuv. When perturbed by a chemical or physical stress (such as a heat shock, nutrient [amino acid] limitation, or addition of IPTG [isopropyl-beta-D-thiogalactopyranoside], acetic acid, ethanol, phenol, antifoam, or salt [osmotic shock]), the E. coli cells produced GFPuv, which was easily detected within the cells as emitted green fluorescence. Temporal and amplitudinal mapping of the responses was performed, and the results revealed regions where quantitative delineation of cell stress was afforded.

Hepatitis C virus NS3/4A protease

Despite an urgent medical need, a broadly effective anti-viral therapy for the treatment of infections with hepatitis C viruses (HCVs) has yet to be developed. One of the approaches to anti-HCV drug discovery is the design and development of specific small molecule drugs to inhibit the proteolytic processing of the HCV polyprotein. This proteolytic processing is catalyzed by a chymotrypsin-like serine protease which is located in the N-terminal region of non-structural protein 3 (NS3). This protease domain forms a tight, non-covalent complex with NS4A, a 54 amino acid activator of NS3 protease. The C-terminal two-thirds of the NS3 protein contain a helicase and a nucleic acid-stimulated nucleoside triphosphatase (NTPase) activities which are probably involved in viral replication. This review will focus on the structure and function of the serine protease activity of NS3/4A and the development of inhibitors of this activity.

Glucose sensor for low-cost lifetime-based sensing using a genetically engineered protein

We describe a glucose sensor based on a mutant glucose/galactose binding protein (GGBP) and phase-modulation fluorometry. The GGBP from Escherichia coli was mutated to contain a single cysteine residue at position 26. When labeled with a sulfhydryl-reactive probe 2-(4'-iodoacetamidoanilino)naphthalene-6-sulfonic acid, the labeled protein displayed a twofold decrease in intensity in response to glucose, with a dissociation constant near 1 microM glucose. The ANS-labeled protein displayed only a modest change in lifetime, precluding lifetime-based sensing of glucose. A modulation sensor was created by combining ANS26-GGBP with a long-lifetime ruthenium (Ru) metal-ligand complex on the surface of the cuvette. Binding of glucose changed the relative intensity of ANS26-GGBP and the Ru complex, resulting in a dramatic change in modulation at a low frequency of 2.1 MHz. Modulation measurements at 2.1 MHz were shown to accurately determine the glucose concentration. These results suggest an approach to glucose sensing with simple devices.

ADVANCES IN FLUORESCENCE SPECTROSCOPY: MULTI-PHOTON EXCITATION, ENGINEERED PROTEINS, MODULATION SENSING AND MICROSECOND RHENIUM METAL-LIGAND COMPLEXES

The technology and applications of fluorescence spectroscopy are rapidly advancing. In this overview presentation we summarize some recent developments from this laboratory. Two and three-photon excitation have been observed for a wide variety of intrinsic and extrinsic fluorophores, including tryptophan, tyrosine, DNA stains, membrane probes, and even alkanes. It has been possible to observe multi-photon excitation of biopolymers without obvious photochemical or photo-thermal effects. Although not de-scribed in our lecture, another area of increasing interest is the use of engineered proteins for chemical and clinical sensing. We show results for the glucose-galactose binding protein from E. coli. The labeled protein shows spectral changes in response to micromolar concentrations of glucose. This protein was used with a novel sensing method based on the modulated emission of the labeled proteins and a long lifetime reference fluorophore. And finally, we describe a recently developed rhenium complex which displays a lifetime near 3 µs in oxygenated aqueous solution. Such long life-time probes allow detection of microsecond dynamic processes, bypassing the usual nanosecond timescale limit of fluorescence. The result of these developments in protein engineering, sensing methods, and metal-ligand probe chemistry will be the increased use of fluorescence in clinical chemistry and point-of-care analyses.

Spi-1/PU.1 is a positive regulator of the Fli-1 gene involved in inhibition of erythroid differentiation in friend erythroleukemic cell lines

Spi-1/PU.1 and Fli-1 are two members of the ETS family of transcription factors whose expression is deregulated by proviral insertion in most erythroleukemic cell lines induced by the spleen focus-forming virus (SFFV) and Friend murine leukemia virus (F-MuLV) components of the Friend viral complex, respectively. In this study, we present evidence that transcription of the Fli-1 gene is positively regulated by Spi-1/PU.1 in SFFV-transformed cell lines: (i) all SFFV-transformed cell lines expressing Spi-1/PU.1 are characterized by a specific pattern of Fli-1 gene transcripts initiated in the -200 region instead of position -400 as reported for F-MuLV-transformed cell lines; (ii) these Fli-1 transcripts initiated in the -200 region are downregulated in parallel with that of Spi-1/PU.1 during hexamethylenebisacetamide (HMBA) induced differentiation; and (iii) Fli-1 transcription is upregulated in SFFV cells lines following stable transfection of a Spi-1/PU.1 expression vector. Furthermore, we found by transient transfection assays that the -270/-41 region of the Fli-1 gene displays promoter activity which is transactivated by Spi-1/PU.1. This promoter is strictly dependent on the integrity of two highly conserved ETS DNA binding sites that bind the Spi-1/PU.1 protein in vitro. Finally, we show that transfection of constitutive or inducible Fli-1 expression vectors in SFFV-transformed cells inhibits their erythroid differentiation induced by HMBA. Overall, these data indicate that Fli-1 is a target gene of the Spi-1/PU.1 transcription factor in SFFV-transformed cell lines. We further suggest that deregulated synthesis of Fli-1 may trigger a common mechanism contributing to erythroleukemia induced by either SFFV or F-MuLV.

Low-frequency modulation sensors using nanosecond fluorophores

We describe a new approach to fluorescence sensing based on a mixture of fluorophores, one of which is sensitive to the desired analyte. If a long-lifetime analyte-insensitive fluorophore is mixed with a short-lifetime analyte-sensitive fluorophore, the modulation of the emission at conveniently low frequencies becomes equal to the fractional fluorescence intensity of the sensing fluorophore. Under these conditions, the modulation can be used to determine the analyte concentration. This can be used with any fluorophore that changes intensity in response to analyte and does not require the sensing fluorophore to display a change in lifetime. The feasibility of modulation-based sensing was demonstrated using mixtures of 6-carboxyfluorescein and [Ru 2,2'-(bipyridyl)3]2+ as a pH sensor and of the calcium probe Fluo-3 and [Ru 2,2'-(bipyridyl)3]2+ as a calcium sensor.

Hepatitis C virus NS3/4A protease

Despite an urgent medical need, a broadly effective anti-viral therapy for the treatment of infections with hepatitis C viruses (HCVs) has yet to be developed. One of the approaches to anti-HCV drug discovery is the design and development of specific small molecule drugs to inhibit the proteolytic processing of the HCV polyprotein. This proteolytic processing is catalyzed by a chymotrypsin-like serine protease which is located in the N-terminal region of non-structural protein 3 (NS3). This protease domain forms a tight, non-covalent complex with NS4A, a 54 amino acid activator of NS3 protease. The C-terminal two-thirds of the NS3 protein contain a helicase and a nucleic acid-stimulated nucleoside triphosphatase (NTPase) activities which are probably involved in viral replication. This review will focus on the structure and function of the serine protease activity of NS3/4A and the development of inhibitors of this activity.

Generating controlled reducing environments in aerobic recombinant Escherichia coli fermentations: effects on cell growth, oxygen uptake, heat shock protein expression, and in vivo CAT activity

The independent control of culture redox potential (CRP) by the regulated addition of a reducing agent, dithiothreitol (DTT) was demonstrated in aerated recombinant Escherichia coli fermentations. Moderate levels of DTT addition resulted in minimal changes to specific oxygen uptake, growth rate, and dissolved oxygen. Excessive levels of DTT addition were toxic to the cells resulting in cessation of growth. Chloramphenicol acetyltransferase (CAT) activity (nmoles/microgram total protein min.) decreased in batch fermentation experiments with respect to increasing levels of DTT addition. To further investigate the mechanisms affecting CAT activity, experiments were performed to assay heat shock protein expression and specific CAT activity (nmoles/microgram CAT min.). Expression of such molecular chaperones as GroEL and DnaK were found to increase after addition of DTT. Additionally, sigma factor 32 (sigma32) and several proteases were seen to increase dramatically during addition of DTT. Specific CAT activity (nmoles/microgram CAT min. ) varied greatly as DTT was added, however, a minimum in activity was found at the highest level of DTT addition in E. coli strains RR1 [pBR329] and JM105 [pROEX-CAT]. In conjunction, cellular stress was found to reach a maximum at the same levels of DTT. Although DTT addition has the potential for directly affecting intracellular protein folding, the effects felt from the increased stress within the cell are likely the dominant effector. That the effects of DTT were measured within the cytoplasm of the cell suggests that the periplasmic redox potential was also altered. The changes in specific CAT activity, molecular chaperones, and other heat shock proteins, in the presence of minimal growth rate and oxygen uptake alterations, suggest that the ex vivo control of redox potential provides a new process for affecting the yield and conformation of heterologous proteins in aerated E. coli fermentations.

Erythrocyte indicators of oxidative stress in gestational diabetes

Foetuses born to mothers with gestational diabetes are at increased risk of developing respiratory distress, foetal macrosomia, foetal anomalies and platelet hyperaggregability. High blood glucose level induces oxidative stress and decreases antioxidant defences. The present study discusses the possibility of lipid peroxidation and protein oxidation in both maternal and foetal erythrocytes as an indicator of oxygen radical activity. The level of lipid peroxidation and protein oxidation in erythrocytes was estimated in 20 mothers with gestational diabetes and their newborns. The maternal age varied between 19 and 42 y and foetal age ranged between 34 and 39 weeks. The proteolytic activities in the erythrocyte lysates obtained from mothers with gestational diabetes and their newborns were significantly greater [(mean +/- SD) 24.41 +/- 9.05 and 16.70 +/- 3.36 microM of amino groups/g haemoglobin, n = 20, respectively] than those from control group (10.18 +/- 4.84 and 14.64 +/- 6.21 microM amino groups/g haemoglobin, n = 15, respectively; p < 0.05 in both cases). Similarly erythrocyte malondialdehyde levels were significantly elevated in babies born to mothers with gestational diabetes (10.11 +/- 2.21 nM/g haemoglobin) when compared to controls (6.8 +/- 3.75 nM/g haemoglobin) (p < 0.05). In the erythrocytes of mothers with gestational diabetes, malondialdehyde levels correlated significantly with glycated haemoglobin levels (p < 0.01). The results of this study indicate that the oxidative stress induced by gestational diabetes manifests as increased lipid peroxidation and protein oxidative damage in the erythrocytes of both mothers with gestational diabetes and their newborn infants.

Steam-sterilizable, fluorescence lifetime-based sensing film for dissolved carbon dioxide

An autoclavable sensing film was developed for monitoring dissolved CO2. The sensing film, based on fluorescence resonance energy transfer (FRET), consisted of a fluorescent donor, an acceptor, and a quaternary ammonium hydroxide, which were doped in a two-component silicone film. As no aqueous solution was used in the sensing film matrix, the sensing film was unaffected by osmotic pressure. Fluorescence lifetime was selected as the sensing parameter, and measured in frequency domain using phase fluorometry. Upon exposure to 20% CO2-saturated water, a 43 degrees increase in phase angle was observed at 100 MHz. The process was fully reversible when the sensing film was exposed to nitrogen-saturated water. The estimated response and recovery times for 90% signal change were 1 min (for a step change from 0 to 6.7% CO2-saturated water) and 1.5 min (for a step change from 6.7 to 3.3% CO2-saturated water). When used for on-line monitoring of dissolved CO2 produced by a culture of Escherichia coli, the sensing film showed a similar trend to that obtained from off-line measurements using a wet chemistry analyzer.