Angiotensin II analogues encompassing 5,9- and 5,10-fused thiazabicycloalkane tripeptide mimetics

A simple experimental procedure on solid phase for the construction of new tripeptidic 5,9- and 5,10-fused thiazabicycloalkane scaffolds that adopt beta-turns has been developed. This N-terminal-directed bicyclization, relying on masked aldehyde precursors derived from glutamic acid as key building blocks, provides a complement to the related bicyclization previously reported, where an aspartic acid-derived precursor was employed to induce cyclization toward the C-terminal end of the peptide. Thus, the regioselectivity of the bicyclization can be altered simply by varying the chain length of the incorporated aldehyde precursor. Four analogues of the hypertensive octapeptide angiotensin II, comprising the new scaffolds in the 3-5- and 5-7-positions, were synthesized. One of these conformationally constrained angiotensin II analogues exhibited AT(1) receptor affinity (K(i) = 750 nM). Results from theoretical conformational analysis of model compounds of the bicyclic tripeptide mimetics are presented, and they demonstrate that subtle differences in geometry have a strong impact on the affinity to the AT(1) receptor.

[Atypical intrathoracic sarcoidosis: a report of 21 cases]

OBJECTIVE

To improve the recognition of atypical intrathoracic sarcoidosis.

METHODS

The clinical data of 21 cases with atypical intrathoracic sarcoidosis were analyzed retrospectively. All the cases had pathological examination data.

RESULTS

The manifestations of atypical intrathoracic sarcoidosis might be as follows: intrapulmonary pathological changes including solitary nodular shadow, atelectasis, unilateral lung consolidation, bilateral lung consolidation and bilateral pulmonary miliary nodes; simple mediastinal lymph node lesion including mediastinal tumor, mediastinal lymph node enlargement plus unilateral pulmonary hilar lymph node enlargement and simple mediastinal lymph node enlargement; pleural lesion including hydropneumothorax and pleural thickening; pulmonary hilar lesion including unilateral pulmonary hilar lymph node enlargement plus mediastinal lymph node enlargement and bilateral pulmonary hilar lymph node enlargement and calcification.

CONCLUSION

The clinical manifestations of atypical intrathoracic sarcoidosis are variable. The establishment of the diagnosis cannot be based on image examination alone. With sufficient knowledge of the clinical manifestations of sarcoidosis and other testing methods, the diagnosis can be made correctly.

[Establishment of hepatitis C virus reproductive model of human peripheral blood mononuclear cells transformed by Epstein-Barr virus]

OBJECTIVE

For the present, one of the crucial questions to study pathogenic mechanism of hepatitis C and its drug therapy is to seek a suitable cell model which may support the replication of hepatitis C virus(HCV). In this article, we made effort on the study of this aspect.

METHODS

Using Epstein-Barr virus(EBV), we transformed the peripheral blood mononuclear cells(PBMC) isolated from a patient diagnosed as chronic hepatitis C. HCV RNA from the cultured cells and the supernatants were analysed by reverse transcriptase-polymerase chain reaction(RT-PCR) at an intervals of one month.

RESULTS

HCV positive-strand RNA could be detected continually in the cultured cells for more than one year since the establishment of the transformed PBMC clone whereas the negative-strand RNA were also observed in the cultured cells. Interestingly, the HCV positive-strand RNA could be identified in supernatants intermittently.

CONCLUSION

HCV may exist in the cultured cell line for a longer period and reproduce in and secrete out of the cells. This will offer a new cell model for studying the molecular biology and immunology of HCV.

Toxicology and pharmacokinetics of intravesical gemcitabine: a preclinical study in dogs

More active and well-tolerated agents are needed for the treatment of superficial bladder cancer. This study investigated intravesical gemcitabine to establish the toxicology and pharmacokinetics necessary for clinical trials. Beagle dogs (in groups of 2; n = 6) received 100 mg, 350 mg, or 1 g of drug by intravesical administration on alternate days three times/week for 4 weeks. Animals were observed for clinical signs of toxicity; gemcitabine levels and peripheral blood counts were taken three times weekly. The dogs were euthanized, and a full necropsy was performed at days 1 and 14 after the last dose. Intravesical gemcitabine was given at 100 mg (n = 2), 350 mg (equivalent to the 1000 mg/m2 human dose; n = 3), and 3.5 g (n = 1). i.v. gemcitabine was given at 350 mg (n = 2). Plasma samples drawn at time points up to 8 h were analyzed for systemic absorption and clearance of drug. Doses of 100 and 350 mg were well tolerated with no clinical side effects. Necropsies revealed normal bone marrow cellularity and normal bladder histology. At 1 g, signs of severe clinical toxicity were evident, and after only three doses, necropsies demonstrated severe bone marrow hypoplasia, cystitis, and intestinal necrosis. At all intravesical doses, significant systemic absorption was seen. The T1/2 (+/- SD) for intravesical and i.v. administration of 350 mg was 328 (+/-6.8) min and 99.3 (+/-5.2) min, respectively (P<0.001). Intravesical gemcitabine is well tolerated and has no direct bladder toxicity at doses up to 1000 mg/m2. Higher doses result in gastrointestinal, bladder, and bone marrow toxicity.

Identification of proteins in complexes by solid-phase microextraction/multistep elution/capillary electrophoresis/tandem mass spectrometry

A method to directly identify proteins in complex mixtures by solid-phase microextraction (micro-SPE)/multistep elution/capillary electrophoresis (CE)/tandem mass spectrometry (MS/MS) is described. A sheathless liquid-metal junction interface is used to interface CE and electrospray ionization MS/MS. A subfemtomole detection limit is achieved for protein identification through database searching using MS/MS data. The SPE serves as a semiseparation dimension using an organic-phase step-elution gradient in combination with the second separation dimension for increased resolving power of complex peptide mixtures. This approach improves the concentration detection limit for CE and allows more proteins in complex mixtures to be identified. A 75-protein complex from yeast ribosome is analyzed using this method and 80-90% of the proteins in the complex can be identified by searching the database using the MS/MS data from a complete analysis. This multidimensional CE/MS/MS methodology provides an alternative to multidimensional liquid chromatography/MS/MS for direct identification of small amounts of protein in mixtures.

Development of a universal immunoenzyme quantitative assay for detecting amplified products of nucleic acid and its preliminary application in hepatitis C virus

OBJECTIVE

To develop a universal quantitative immunoenzyme assay (EIA) for detecting amplified products of nucleic acid and its application in hepatitis C virus (HCV).

METHODS

The appropriate cycle number of amplification was selected to stop polymerase chain reaction (PCR) before the "plateau stage". At the same time, primers HCV (3) of the second PCR were modified with biotin so that the amplified products were labeled. The products were diluted and subsequently added to the streptavidin-coated wells, and the biotinylated products were captured, followed by denaturation of NaOH, and non-biotinylated strands were removed. Hybridization was performed by adding the specific probe labeled with fluorescein. Finally antifluorescein horse radish peroxidase (HRP) conjugates were added, after washing, 3, 3', 5, 5',-tetramethylbenzidine (TMB) was added to the wells and then measured on a microplate reader.

RESULTS

EIA detection of amplified products of HCV showed that this assay was rapid, sensitive, specific and accurate. Correlation between the initial number of viral template and the EIA of amplified products was good. We also prospectively investigated the response to interferon in five patients with HCV coinfection. Results showed that this assay could be used as a guidance to the clinical therapy in directing the use of antiviral drugs.

CONCLUSIONS

This assay could be widely used as a universal technique for the quantitative detection of amplified products of all nucleic acid (such as virus, bacterium) and other human genes (such as HLA B27), it has vast vistas.

Involvement of lipid mediators on cytokine signaling and induction of secretory phospholipase A2 in immortalized astrocytes (DITNC)

Our previous studies demonstrated the ability of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin 1beta (IL-1beta), to stimulate NFkappaB/DNA binding and synthesis of secretory phospholipase A2 (sPLA2) in immortalized astrocytes (DITNC). In this study, we examined possible involvement of lipid mediators in the cytokine action. Using [14C]serine to label sphingomyelin and ceramide in these cells, subsequent exposure of cells to cytokines did not result in alteration of sphingomyelin/ceramide ratio. Furthermore, neither exogenous sphingomyelinase nor cell-permeable ceramides could stimulate NFkappaB/DNA binding. On the other hand, C-2 ceramide (0.3 microM) as well as other lipid mediators, such as lysophosphatidylcholine and arachidonic acid, were able to elicit a small increase in sPLA2 and potentiate the induction of sPLA2 by TNF-alpha. When DITNC cells were prelabeled with [32P]Pi, an increase in labeled phosphatidic acid (PA) was observed on treatment of cells with IL-1beta (200 U/mL). However, despite the ability of phorbol myristate acetate (PMA) to stimulate phospholipase D (PLD) and synthesis of phosphatidylethanol (PEt) in these cells, PLD activity was not affected by IL-1beta. With the [32P]labeled cells, however, PA-phosphohydrolase inhibitors, such as chlorpromazine and propranolol, could elicit large increases in labeled PA, indicating active PA metabolism in these cells. Cytokines also caused an increase in levels of diacylglycerol (DG) in these cells, although the source of this lipid pool is presently not understood. Taken together, these results provide evidence for the participation of PA and DG in cytokine signaling activity. Furthermore, although cytokines did not cause the release of ceramide, lipid mediators, such as lysophospholipids, and AA could modulate cytokine-mediated induction of sPLA2 in astrocytes.

Progesterone inhibits estrogen-induced cyclin D1 and cdk4 nuclear translocation, cyclin E- and cyclin A-cdk2 kinase activation, and cell proliferation in uterine epithelial cells in mice

The response of the uterine epithelium to female sex steroid hormones provides an excellent model to study cell proliferation in vivo since both stimulation and inhibition of cell proliferation can be studied. Thus, when administered to ovariectomized adult mice 17beta-estradiol (E2) stimulates a synchronized wave of DNA synthesis and cell division in the epithelial cells, while pretreatment with progesterone (P4) completely inhibits this E2-induced cell proliferation. Using a simple method to isolate the uterine epithelium with high purity, we have shown that E2 treatment induces a relocalization of cyclin D1 and, to a lesser extent, cdk4 from the cytoplasm into the nucleus and results in the orderly activation of cyclin E- and cyclin A-cdk2 kinases and hyperphosphorylation of pRb and p107. P4 pretreatment did not alter overall levels of cyclin D1, cdk4, or cdk6 nor their associated kinase activities but instead inhibited the E2-induced nuclear localization of cyclin D1 to below the control level and, to a lesser extent, nuclear cdk4 levels, with a consequent inhibition of pRb and p107 phosphorylation. In addition, it abrogated E2-induced cyclin E-cdk2 activation by dephosphorylation of cdk2, followed by inhibition of cyclin A expression and consequently of cyclin A-cdk2 kinase activity and further inhibition of phosphorylation of pRb and p107. P4 is used therapeutically to oppose the effect of E2 during hormone replacement therapy and in the treatment of uterine adenocarcinoma. This study showing a novel mechanism of cell cycle inhibition by P4 may provide the basis for the development of new antiestrogens.

Bicyclic tripeptide mimetics with reverse turn inducing properties

Analogues of the hypertensive octapeptide angiotensin II, comprising novel constrained 5,8-bicyclic and 5,9-bicyclic tripeptide units adopting nonclassical beta-turn geometries, as deduced from theoretical conformational analysis, have been synthesized. Spontanous bicyclization upon acid-catalyzed deprotection of a model peptide, encompassing a protected omega-formyl alpha-amino acid in position 5 and cysteine residues in positions 3 and 7, revealed a strong preference for bicyclization toward the C-terminus. The bicyclic thiazolidine related angiotensin II analogues synthesized exhibited no affinity for the angiotensin II AT1 receptor.

[Slow transit constipation treated by surgery: analysis of 17 cases]

OBJECTIVE

To explore the operative indications, prognosis, and possible pathogenic factors of slow transit constipation (STC).

METHODS

17 cases with STC who had undergone colectomy were analysed.

RESULTS

Bowel movement frequency was once per 4 to 14 days in all of the patients, who had had long-term laxative abuse. Delayed colonic transit was demonstrated in all patients, 82.4% of them were accompanied by outlet obstructive constipation (OOC) and 50% showed abnormal sex hormones. Reduced numbers of argyrophilic neurons and vacuolar degeneration of axons were demonstrated at the myenteric plexus pathologically. Three patients had adhesive ileus postoperatively and one patient suffered from difficult evacuation again 5 years after the operation.

CONCLUSIONS

Colectomy is highly effective in alleviating symptoms in patients with STC, and pelvic floor disorder of OOC should be treated simultaneously.

Comparison of estrogen receptor alpha and beta subtypes based on comparative molecular field analysis (CoMFA)

A substantial body of evidence indicates that both humans and wildlife suffer adverse health effects from exposure to environmental chemicals that are capable of interacting with the endocrine system. The recent cloning of the estrogen receptor beta subtype (ER-beta) suggests that the selective effects of estrogenic compounds may arise in part by the control of different subsets of estrogen-responsive promoters by the two ER subtypes, ER-alpha and ER-beta. In order to identify the structural prerequisites for ligand-ER binding and to discriminate ER-alpha and ER-beta in terms of their ligand-binding specificities, Comparative Molecular Field Analysis (CoMFA) was employed to construct a three-dimensional Quantitative Structure-Activity Relationship (3D-QSAR) model on a data set of 31 structurally-diverse compounds for which competitive binding affinities have been measured against both ER-alpha and ER-beta. Structural alignment of the molecules in CoMFA was achieved by maximizing overlap of their steric and electrostatic fields using the Steric and Electrostatic ALignment (SEAL) algorithm. The final CoMFA models, generated by correlating the calculated 3D steric and electrostatic fields with the experimentally observed binding affinities using partial least-squares (PLS) regression, exhibited excellent self-consistency (r2 > 0.99) as well as high internal predictive ability (q2 > 0.65) based on cross-validation. CoMFA-predicted values of RBA for a test set of compounds outside of the training set were consistent with experimental observations. These CoMFA models can serve as guides for the rational design of ER ligands that possess preferential binding affinities for either ER-alpha or ER-beta. These models can also prove useful in risk assessment programs to identify real or suspected EDCs.

Derivation of a pharmacophore model for anandamide using constrained conformational searching and comparative molecular field analysis

Constrained molecular dynamics simulations on anandamide, together with a systematic distance comparison search, have revealed a specific low-energy conformer whose spatial disposition of the pharmacophoric elements closely matches that of HHC. This conformer enables near superposition of the following: (1) the oxygen of the carboxyamide and the phenolic hydroxyl group of HHC, (2) the hydroxyl group of the ethanol and the cyclohexyl hydroxyl group of HHC, (3) the alkyl tail and the lipophilic side chain of HHC, and (4) the polyolefin loop and the tricyclic ring structure of HHC. The close matching of common pharmacophoric elements of anandamide with HHC offers persuasive evidence of the biological relevance of this conformer. The proposed pharmacophore model was capable of discriminating between structurally related compounds exhibiting different pharmacological potency for the CB1 cannabinoid receptor, i.e., anandamide and N-(2-hydroxyethyl)prostaglandinamide. Furthermore, a 3D-QSAR model was derived using CoMFA for a training set of 29 classical and nonclassical analogues which rationalized the binding affinity in terms of steric and electrostatic properties and, more importantly, which predicted the potency of anandamide in excellent agreement with experimental data. The ABC tricyclic HU-210/HU-211 and ACD tricyclic CP55,243/CP55,244 enantiomeric pairs were employed as test compounds to validate the present CoMFA model. For each enantiomeric pair, the CoMFA-predicted log Ki values correctly identified that enantiomer exhibiting the higher affinity for the receptor.

Dose-dense therapy with weekly 1-hour paclitaxel infusions in the treatment of metastatic breast cancer

PURPOSE

To evaluate the efficacy and toxicity of paclitaxel administered as a 1-hour infusion on weekly basis, without interruption, to patients with metastatic breast cancer who had received prior therapy.

PATIENTS AND METHODS

Thirty patients with metastatic breast cancer received sustained weekly paclitaxel therapy at an initial dose of 100 mg/m2 until disease progression. Prior therapy included adjuvant only (n=17), metastatic only (n=7), or both (n=6). Eighteen patients had received prior anthracycline therapy, 12 of whom had demonstrated progression of disease within 12 months of it. All patients were assessable for efficacy; 29 patients were assessable for toxicity. Pharmacokinetic studies of paclitaxel were also performed.

RESULTS

A total of 469 weekly paclitaxel infusions were administered to 30 patients (median, 14 infusions/patient). The median delivered dose-intensity was 91 mg/m2/wk (range, 80 to 108). The overall response rate was 53% (95% confidence interval [CI], 34% to 72%), with 10% complete responses (CRs) and 43% partial responses (PRs). Median response duration was 7.5 months (range, 2 to 11+). Responses were observed in nine of 18 (50%) patients with prior anthracycline therapy, including six of 12 (50%) with disease progression on anthracycline within 1 year (three of four within 6 months). Therapy was well tolerated and remarkable for a lack of overall and cumulative myelosuppression. Grade 3/4 neutropenia occurred in four patients; febrile neutropenia was not observed. Peripheral neuropathy prohibited dose escalation above 100 mg/m2, and grade 3 neuropathy was observed in two of 21 patients at < or = 100 mg/m2.

CONCLUSION

Weekly paclitaxel therapy is active and well tolerated in patients with metastatic breast cancer. Weekly therapy should be considered as a current clinical option for these patients and should be incorporated into future comparative clinical trials.

Intraocular concentrations of chemotherapeutic agents after systemic or local administration

OBJECTIVES

To investigate the concentrations of carboplatin and etoposide achieved in the aqueous and vitreous humors after intravenous infusion in nonhuman primates, and to investigate whether local administration of carboplatin might result in higher concentrations in the vitreous humor.

METHODS

Macaca fascicularis primates were treated with 1 of 3 regimens: (1) intravenous carboplatin (18.7 mg/kg), etoposide (5 mg/kg), and vincristine sulfate (0.05 mg/kg), (2) peribulbar carboplatin (10 mg/mL), or (3) episcleral balloon carboplatin (10 mg/mL). Concentrations of chemotherapeutic agents were measured in the plasma and in the aqueous and vitreous humors.

RESULTS

No measurable amount of etoposide was detected in the aqueous or vitreous humor after intravenous administration. Mean measured peak vitreous concentration of carboplatin after intravenous administration was 0.31 microg/mL, which was 1% of the peak plasma value. Mean measured peak vitreous concentrations of carboplatin after peribulbar or episcleral balloon administration were 2.38 microg/mL and 2.95 microg/mL, respectively, which represent 7.68- and 9.52-fold increases over the concentration achieved after intravenous administration. No serious toxic effect was observed in any animal.

CONCLUSIONS

Peribulbar and episcleral balloon administration of carboplatin seemed to be safe and resulted in higher vitreous concentrations than intravenous administration in this model. These results suggest that these alternate routes of delivery should be explored in children with vitreous seeding of retinoblastoma.

The absence of p27Kip1, an inhibitor of G1 cyclin-dependent kinases, uncouples differentiation and growth arrest during the granulosa->luteal transition

The involvement of cyclin-dependent kinase inhibitors in differentiation remains unclear: are the roles of cyclin-dependent kinase inhibitors restricted to cell cycle arrest; or also required for completion of the differentiation program; or both? Here, we report that differentiation of luteal cells can be uncoupled from growth arrest in p27-deficient mice. In these mice, female-specific infertility correlates with a failure of embryos to implant at embryonic day 4.5. We show by ovarian transplant and hormone reconstitution experiments that failure to regulate luteal cell estradiol is one physiological mechanism for infertility in these mice. This failure is not due to a failure of p27-deficient granulosa cells to differentiate after hormonal stimulation; P450scc, a marker for luteal progesterone biosynthesis, is expressed and granulosa cell-specific cyclin D2 expression is reduced. However, unlike their wild-type counterparts, p27-deficient luteal cells continue to proliferate for up to 3.5 days after hormonal stimulation. By day 5.5, however, these cells withdraw from the cell cycle, suggesting that p27 plays a role in the early events regulating withdrawal of cells from the cell cycle. We have further shown that in the absence of this timely withdrawal, estradiol regulation is perturbed, explaining in part how fertility is compromised at the level of implantation. These data support the interpretation of our previous observations on oligodendrocyte differentiation about a role for p27 in establishing the nonproliferative state, which in some cases (oligodendrocytes) is required for differentiation, whereas in other cases it is required for the proper functioning of a differentiated cell (luteal cell).

Laser-induced native fluorescence (LINF) imaging of serotonin depletion in depolarized neurons

Since certain neurotransmitters exhibit native fluorescence we can monitor this property to disclose intracellular changes that result from neurotransmitter release. Isolated Retzius neurons of the leech are known to release serotonin (5-HT) during depolarization. Using intensified CCD technology coupled with UV laser (305 nm) excitation we observed depolarization and calcium-dependent reductions in native fluorescence in the axon, as well as in the cortex of the cell body. When taken together with data obtained from single-cell capillary electrophoresis, we demonstrate that this laser-induced native fluorescence can be reliably used to study spatial and temporal changes in intracellular transmitter content that accompany calcium-dependent secretion.

Evaluation of quantitative structure-activity relationship methods for large-scale prediction of chemicals binding to the estrogen receptor

Three different QSAR methods, Comparative Molecular Field Analysis (CoMFA), classical QSAR (utilizing the CODESSA program), and Hologram QSAR (HQSAR), are compared in terms of their potential for screening large data sets of chemicals as endocrine disrupting compounds (EDCs). While CoMFA and CODESSA (Comprehensive Descriptors for Structural and Statistical Analysis) have been commercially available for some time, HQSAR is a novel QSAR technique. HQSAR attempts to correlate molecular structure with biological activity for a series of compounds using molecular holograms constructed from counts of sub-structural molecular fragments. In addition to using r2 and q2 (cross-validated r2) in assessing the statistical quality of QSAR models, another statistical parameter was defined to be the ratio of the standard error to the activity range. The statistical quality of the QSAR models constructed using CoMFA and HQSAR techniques were comparable and were generally better than those produced with CODESSA. It is notable that only 2D-connectivity, bond and elemental atom-type information were considered in building HQSAR models. Since HQSAR requires no conformational analysis or structural alignment, it is straightforward to use and lends itself readily to the rapid screening of large numbers of compounds. Among the QSAR methods considered, HQSAR appears to offer many attractive features, such as speed, reproducibility and ease of use, which portend its utility for prioritizing large numbers of potential EDCs for subsequent toxicological testing and risk assessment.

Studies on diffusion maximum in x-ray diffraction patterns of plasma-sprayed hydroxyapatite coatings

Study of an amorphous phase in plasma-sprayed hydroxyapatite (HA) coatings is important owing to its unique characteristics and nonnegligible amount of the amorphous phase compared to crystalline HA. However, little is known about the component parts of an amorphous phase. It is known that amorphous phase usually appears as the diffusion maximum (Dmax) in X-ray diffraction (XRD) patterns. Analyzing Dmax, including the position (Pmax) and area of Dmax, we can indicate the component parts of an amorphous phase and their transitions. In this study, the variation of Dmax in XRD patterns of the coatings during plasma spraying, in postheating, and in dissolving in vitro was studied with the aid of XRD. It was found that component parts of the amorphous phase in the coating varied with increasing thickness, consisting of two part represented by Dmax1, located between 29.4 and 29.8 degrees (2 theta), and Dmax2, located between 31.0 and 31.4 degrees (2 theta). It was concluded that Dmax3, located between 32.0 and 32.4 degrees (2 theta), should be referred to as nanocrystals of HA. In addition, the particle size of the starting powder may affect the component parts of the amorphous phase in the coating in addition to thickness. With vacuum heating (650 degrees C) and water vapor treatment at a low temperature (125 degrees C) in a saturated vaporic atmosphere, transition of the amorphous components was not as efficient as that at 490 degrees C with water vapor. The reason might be that the amorphous-to-crystalline HA conversion is dependent on both temperature and water vapor pressure. It was found that amorphous components were transformed completely into crystalline HA after heating at 490 degrees C with a partial water vapor pressure of 0.01 MPa for 2 h. It was concluded that the unstable amorphous components (Dmax1, Dmax2) converted into more stable nanocrystals of HA (Dmax3). Degradation in vitro showed that Dmax3 was more stable than Dmax1 and Dmax2. It was concluded that nucleation of apatite in vitro should be attributed to nanocrystals of HA (Dmax3) except for the amorphous components. It is recommended that the optimal phasic contents of the plasma-sprayed HA coating be mainly composed of crystalline HA and nanocrystals of HA (Dmax3) in terms of the stability and biocompatibility of the coating.

[Study on HSP70, 90 mRNA gene expression in peripheral blood mononuclear cells with steroid-resistant asthmatics]

OBJECTIVE

To investigate the role of heat shock protein(HSP) 70, 90 alpha, 90 beta mRNA on the pathogenesis of steroid-resistant(SR) asthma.

METHOD

9 SR asthmadics 16 steroid sensitive (SS) asthmatics and 10 normal healthy volunteers were studied. With reverse transcription-polymerase chain reaction(RT-PCR), the expression of hsp70, 90 alpha, 90 beta mRNA were detected in peripheral blood mononuclear cell(PMBC) from normal volunteers and SR. steroid-sensitive(SS) asthmatics. Inhibition of PHA-induced lymphocyte proliferation by dexamethasones (Dex) was investigated using lymphocyte proliferation assay.

RESULT

There were no expression of hsp70mRNA in PMBC of normal volunteers; the levels of expression of hsp70, 90 alpha, 90 beta mRNA in PBMC of SR asthmatics (70 = 2.95 +/- 1.12, 90 alpha = 2.17 +/- 0.89, 90 beta = 2.22 +/- 0.83) were significantly higher than SS asthmatics (70 = 0.23 +/- 0.09, 90 alpha = 1.07 +/- 0.39, 90 beta = 0.94 +/- 0.32) (P < 0.01) and normal volunteers (70 = 0, 90 alpha = 0.45 +/- 0.19, 90 beta = 0.32 +/- 0.15) (P < 0.01); There were significantly positive correlation between the degree of inhibition by Dex(10(-7) mol/L) of SR, SS asthmatics of proliferation of T lymphocytes and the expression of hsp70, 90 alpha, 90 beta mRNA in PMBC(P < 0.01).

CONCLUSION

There were expression of hsp70, 90 alpha, 90 beta gene in PMBC from SR asthmatics, but increased with worsening of inflammation and prolonging of the duration of disease. The more hsp 90 gene expression, the less T lymphocytes were inhibited by Dex.

Characterization of Y122F R2 of Escherichia coli ribonucleotide reductase by time-resolved physical biochemical methods and X-ray crystallography

Ribonucleotide reductase (RNR) from Escherichia coli catalyzes the conversion of ribonucleotides to deoxyribonucleotides. It is composed of two homodimeric subunits, R1 and R2. R2 contains the diferric-tyrosyl radical cofactor essential for the nucleotide reduction process. The in vitro mechanism of assembly of this cluster starting with apo R2 or with a diferrous form of R2 has been examined by time-resolved physical biochemical methods. An intermediate, Fe3+/Fe4+ cluster (intermediate X), has been identified that is thought to be directly involved in the oxidation of Y122 to the tyrosyl radical (*Y122). An R2 mutant in which phenylalanine has replaced Y122 has been used to accumulate intermediate X at sufficient levels that it can be studied using a variety of spectroscopic methods. The details of the reconstitution of the apo and diferrous forms of Y122F R2 have been examined by stopped-flow UV/vis spectroscopy and by rapid freeze quench electron paramagnetic resonance, and Mössbauer spectroscopies. In addition the structure of this mutant, crystallized at pH 7.6 in the absence of mercury, at 2.46 A resolution has been determined. These studies suggest that Y122F R2 is an appropriate model for the examination of intermediate X in the assembly process. Studies with two mutants, Y356F and double mutant Y356F and Y122F R2, are interpreted in terms of the possible role of Y356 in the putative electron transfer reaction between the R1 and R2 subunits of this RNR.

Osteogenic responses to extraskeletally implanted synthetic porous calcium phosphate ceramics: an early stage histomorphological study in dogs

In this experiment, synthetic porous calcium phosphate ceramics (hydroxyapatite-tricalcium phosphate) were prepared and implanted in dorsal muscles of dogs. The purpose was to study the biological processes prior to and during the morphogenesis of bone in extraskeletally implanted porous calcium phosphate ceramics. Specimens were harvested after implantation for 7, 15, 30, 45, 60, 90 and 120 days. Decalcified and undecalcified sections were prepared for alkaline phosphatase (ALP) histochemical localization and comparative histological analysis. The results show that bone morphogenesis in the pore regions of the extraskeletally implanted ceramics follows a complex process involving clot formation, vascular invasion, granulation-like tissue formation, polymorphic cell aggregation, osteoblast differentiation and bone formation. The characteristic feature preceding bone formation was polymorphic cell aggregation on the pore inner surface and near the invading capillaries or small venules. These cells were of various sizes and shapes, and some of them were positive for ALP activity. ALP-positive cell aggregates were more numerous where capillaries or venules were close to the pore inner surface. Osteoblast differentiation occurred within the cell clusters aggregated on the pore inner surface and bone matrix was secreted in direct contact with the ceramics. During bone formation, capillaries or small venules were always found close to the developing fronts of the osseous nidi. It is suggested that those cells which first appeared near the invading vasculature, the cells which aggregated on the pore inner surface and those cells which finally differentiated into osteoblasts may be interrelated in some way.

Characterization of hydroxyapatite film with mixed interface by Ar+ ion beam enhanced deposition

Ar+ ion beam enhanced deposition (IBED) was used to produce a hydroxyapatite (HA) film on polished titanium substrates. In this study, the HA ceramic target was sputtered by an argon-ion beam with an energy of 1.5 KeV, and the sputtered film was intermittently bombarded by energetic argon-ions at 60 KeV. An effective Ca-Ti mixed layer produced by the energetic argon-ion bombardment was confirmed by using Auger electron spectroscopy. The characteristics of the deposited films were evaluated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. XRD analysis revealed that the as-deposited film was amorphous, and a hydroxyapatite-type structure was obtained from the post-heat treatment of the deposited films. SEM observations showed that no distinct difference in surface morphology was found between the as-deposited and heat-treated samples for Ar+ IBED films, suggesting a strongly bonded HA film on the titanium substrate. In comparison with the HA target, some chemistry alterations were brought about in the deposited films, such as the incorporation of CO3, the loss of the OH groups and some distortion of the phosphate lattice.

9-Aminocamptothecin by 72-hour continuous intravenous infusion is inactive in the treatment of patients with 5-fluorouracil-refractory colorectal carcinoma

BACKGROUND

9-Aminocamptothecin (9AC) and its parent compound, camptothecin, have shown outstanding preclinical activity against colorectal carcinoma. Irinotecan (CPT-11), another camptothecin derivative, has demonstrated clinical activity in patients with 5-fluorouracil (5-FU)-refractory colorectal carcinoma.

METHODS

The authors performed a Phase II trial of 9AC involving patients with measurable metastatic colorectal carcinoma who had progressed through only one prior regimen of 5-FU-based chemotherapy. 9AC was given initially at a dose of 59 microg/m2/hour by continuous intravenous infusion for 72 hours, with treatments repeated every 14 days. Granulocyte-colony stimulating factor was given on Days 5-12.

RESULTS

Sixteen patients were treated on this trial. Fourteen were evaluable for response. Contrary to expectations, no major objective antitumor responses were observed. Eight patients experienced stable disease for a median of 4.1 months (range, 2.2-9.5 months). Toxicities, especially myelosuppression, were severe and necessitated a 15% reduction in the initial dose after the first 9 patients. Toxicities at this reduced dose remained unacceptable.

CONCLUSIONS

9AC did not demonstrate substantial activity against 5-FU-refractory colorectal carcinoma on the schedule studied. Toxicities at the doses and schedule studied were unacceptable in this patient population. Based on their results, the authors consider it unlikely that 9AC administered as a 72-hour continuous intravenous infusion will play a major role in the treatment of colorectal carcinoma.

On-column monitoring of secretion of catecholamines from single bovine adrenal chromaffin cells by capillary electrophoresis

The secretion of catecholamines from individual bovine adrenal medullary cells was quantitatively monitored by capillary electrophoresis with laser-induced native fluorescence detection. By using a physiological balanced-salt solution as the running buffer for CE, the amount of norepinephrine (NE) and epinephrine (E) secreted by their physiological secretagogue, acetylcholine, and the amount remaining in a single cell can be simultaneously quantified. Among the six different glands (from separate cows) studied, a predominance of E-rich cells were found. There was no apparent relationship between the ratio of NE/E released and the original NE/E content in the cell. The secretion process was also monitored dynamically with this method by continuously passing acetylcholine over the cell during stimulation. From the peak width and shape of the released material, one can estimate the time scale of the release process.