Sustained-release butorphanol microparticles

Various butorphanol-loaded microparticles have been prepared with a biodegradable copolymer P(FAD-SA) of erucic acid dimer (FAD) and sebacic acid (SA) and a copolymer P(CPP-SA) of carboxyphenoxypropane (CPP) and SA using a melt compounding and milling method. Drug release was measured in vitro following incubation of drug-loaded microparticles in water for injection at 37 degrees C. It was found that butorphanol was released in a sustained manner, yielding a cumulative drug release of about 100% over a period of 48 hr. Also, drug release was affected by drug loading and the size of the microparticles; however, it was not significantly influenced by the copolymer composition. Scanning electron microscopic (SEM) results showed that most of the particles were irregular in shape with uneven surfaces. The molecular weights of the copolymers were not changed after this fabrication process. In addition, 20% butorphanol-encapsulated microspheres were prepared with copolymer P(FAD-SA) by spray-drying. The SEM micrograph shows that the particle sizes of the microspheres ranged from 2 to 10 microns, and the external surfaces appear smooth. Moreover, rapid drug release was observed for these microspheres, with more than 92% of the encapsulated drug released within the first 2 hr.

Particle size determination of a three-component suspension using a laser-scattering particle size distribution analyzer

In this study, a rapid and accurate particle size determination method using a light-scattering particle size analyzer was developed to measure the particle size and size distribution of a suspension containing three solid components: clotrimazole, triamcinolone, and sarafloxacin, which have different refractive indices. To ensure that data represent the size distribution of the primary particles of the suspension, the optimal sonication prior to and during measurement was determined. It was found that the results obtained using the average relative refractive index (RRI) of the three components agreed with the results obtained using three individual RRIs. In addition, the results from two analysts demonstrated good reproducibility of this method. The size distribution data of the suspension were also compared to those of the bulk drugs. The results showed that the median particle size of this three-component suspension is relatively close to that of clotrimazole, which accounts for 80% of solid particles in the suspension. Furthermore, the results obtained using the light-scattering technique were comparable to those obtained using a polarized light microscope equipped with an image analyzer, indicating acceptable accuracy of this technique.

Biotransformation of 13(Z)-retinoic acid in mouse skin and human keratinocyte cultures

The metabolism of 13-(CIS) in mouse skin in vivo which was treated with TPA (or vehicle) typically showed that the retinoid was oxidized to 4-hydroxy, 5,6-epoxy-13-CIS, 5,8-oxy-13-CIS and undergoes geometric isomerization to RA. Applied 13-(CIS) in human keratinocyte cultures showed that the retinoid was oxidized to 5,6-epoxy-13-CIS, 5,8-oxy-13-CIS, and isomers. Pretreatment with the antioxidant butylated hydroxyanisole(BHA) resulted in a large decrease in formation of the oxirane and increased formation of the alcohol in mouse skin. Proposed mechanisms suggested the involvement of peroxyl radicals and prostaglandin H synthase for the biotransformation of retinoids.

Familial risk of hepatocellular carcinoma among chronic hepatitis B carriers and their relatives

BACKGROUND

Familial predisposition as a risk factor for hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) carriers has not been thoroughly explored.

METHODS

The HCC risk associated with having parents and/or siblings with HCC was evaluated by use of a cohort study of 4808 male HBV carriers. A case-control family study was also conducted on data from first-degree relatives of 553 HBV carriers who had newly diagnosed HCC (case subjects) and 4684 HBV carriers without HCC (control subjects).

RESULTS

In the cohort study, HBV carriers with a family history of HCC had a multivariate-adjusted rate ratio for HCC of 2.41 (95% confidence interval [CI] = 1.47-3.95) compared with HBV carriers without a family history of HCC. For carriers with two or more affected relatives, the ratio increased to 5.55 (95% CI = 2.02-15.26). Cumulative HCC risk by age 70 years was 235.6 per 1000 (95% CI = 95. 3-375.9 per 1000) for HBV carriers with family history compared with 88.9 per 1000 (95% CI = 67.9-109.9 per 1000) for those without. In the case-control family study, first-degree relatives of case subjects were more likely to have HCC (age-sex-adjusted odds ratio [OR] = 2.57; 95% CI = 2.03-3.25) than first-degree relatives of control subjects. The excess risk of HCC among relatives was particularly evident in siblings (sisters-age-adjusted OR = 4.55 [95% CI = 2.22-9.31]; brothers-age-adjusted OR = 3.73 [95% CI = 2. 64-5.27]), but it was also observed in parents. The cumulative risk of HCC to age 80 years was 83.0 per 1000 among relatives of case subjects and 42.0 per 1000 among relatives of control subjects. Among relatives of case subjects, the cumulative risk of HCC was greater if the case subjects were diagnosed before age 50 years (two-sided P =.047). Liver cirrhosis was 2.29 (95% CI = 1.68-3.11) times more frequent in relatives of case subjects than in relatives of control subjects.

CONCLUSIONS

First-degree relatives of patients with HBV-related HCC appear to be at increased risk of HCC and should be considered in the formulation of HCC-screening programs.

Effect of acupuncture at Hsien-Ku (St-43) on the pulse spectrum and a discussion of the evidence for the frequency structure of Chinese medicine

We investigated the pulse spectrum variation of the human radial artery when Hsien- Ku (St 43), an acupoint on the stomach meridian, was needled and compared the results with the acupuncture effects of two other acupoints, Tsu-San-Li (St-36) and Tai-Shih (K-3), reported previously. For Hsien-Ku, the harmonic proportions were redistributed: the second harmonic (C2) decreased, C3, C5, C6, C7, C8 and C9 increased, C3, C6 and C9 became the relative peaks to their neighboring harmonics and C2, C4 became the relative minimums. The phase angles of the 2nd harmonic (P2) and 5th harmonic (P5) decreased, propagating faster. These effects were similar to that of Tsu-San-Li which is also on the stomach meridian. A totally different pattern was found for Tai-Shih on the kidney meridian. These results strengthen the theory that a meridian can be classified according to its effects on the pulse spectrum, and that all the meridian related effects such as those caused by acupuncture or meridian specific herbs are frequency specific.

Propofol inhibits renal cytochrome P450 activity and enflurane defluorination in vitro in hamsters

PURPOSE

To determine the effect of propofol on renal cytochrome P450 activity and defluorination of enflurane.

METHODS

Renal microsomes were prepared by homogenization and differential centrifugation from pooled hamster kidneys. Defluorination of enflurane was assessed by measuring free fluoride metabolites after reacting enflurane with renal microsomes incubated with various concentrations, 0.05 - 1.0 mmol x L(-1) propofol in the NADPH-generating system. Drug metabolizing activities of renal cytochrome P450 mono-oxygenase enzymes were evaluated within microsomes preincubated with propofol and reacted with the specific marker substrates, aniline, benzo(a)pyrene, erythromycin and pentoxyresorufin, for cytochrome P450 2E1, 1A1, 3A4 and 2B1, respectively.

RESULTS

Renal defluorination of enflurane was inhibited by clinical concentrations, 0.05 mmol x L(-1) of propofol (P < 0.05). Dose-dependent inhibition of defluorination, aniline and benzo(a)pyrene hydroxylase within kidney microsomes was related to propofol concentration. Propofol demonstrated a profound inhibition of renal pentoxyresorufin dealkylase activity even at low concentrations, 0.05 mmol x L(-1) (P < 0.01). Propofol did not exhibit inhibition of erythromycin N-demethylation of kidney microsomes except at high concentration, 1.0 mmol x L(-1). Spectral analyses of key coenzymes of renal cytochrome P450 monooxygenase, cytochrome b5 and cytochrome c reductase, demonstrated an inhibition when incubated with high concentrations of propofol (P < 0.05).

CONCLUSION

In an in vitro study in an NADPH-generating system of hamster kidney microsomes, propofol, in clinical concentrations, exhibited a broad-spectrum of inhibition to renal monooxygenase activities and enflurane defluorination.

Modulation of cytochrome P450-dependent monooxygenases in streptozotocin-induced diabetic hamster: II. Reverse role of insulin in P450 activity and defluorination

BACKGROUND

Metabolic activities of cytochrome (cyt) P450-dependent monooxygenase could be modulated by diabetic state in experimental diabetic animals. The purpose of this study is to validate the effect of insulin on the modulation of the metabolic activity of cyt P450 and the defluorination ability to inhalational anesthetics in diabetic animals.

METHODS

Diabetic state in golden Syrian hamsters was achieved by intraperitoneal injection of streptozotocin 40 mg/kg once a day for 4 days. After stabilization of diabetic state for 6 weeks, a regimen of insulin treatment given subcutaneously was carried out. Metabolic activities of cyt P450 were assessed by the reaction with benzo(a) pyrene, pentoxyresorufin, aniline and erythromycin (specific substrates). The metabolic activities of cyt 1A1, 2B1, 2E1 and 3A4 respectively in a NADPH-generating system in microsomal preparations of the diabetic hamsters were observed before and after insulin treatment, and were compared with the control group. The ability of defluorination was evaluated by measuring the free fluoride metabolites after incubating the microsomes with enflurane in diabetic and insulin-treated hamsters. Contents of cyt P450 isozymes were measured by electrophoresis and immunoblotting before and after insulin treatment. Pathological features of hepatocytes in diabetic hamsters were evaluated microscopically before and after insulin treatment.

RESULTS

The defluorination of enflurane and activity of aniline hydroxylase (cyt 2E1) were successfully induced by diabetic state (P < 0.01). The pentoxyresorufin O-dealkylase (cyt 2B1) was inhibited nearly 50% in the diabetic hamster liver when compared with that of control (P < 0.01). While the activities of benzo(a)pyrene hydroxylase (cyt 1A1) and the erythromycin N-demethylase (cyt 3A4) were basically unaffected by diabetes, alterations in content of cyt P450 were parallel to the alterations in enzyme activities. Microscopically, diabetes induced vacuolization with fatty droplets in the hepatocytes. After treatment with insulin injection, the enzyme activities, protein content and pathologic features returned to the baseline similar to the control.

CONCLUSIONS

Our data demonstrated that under diabetic state, metabolic activities of cyt P450 and its extent of defluorination would be polymorphically modulated. After administration of insulin, the activities of cyt P450 and defluorination of enflurane returned to baseline as the blood sugar level had been normalized. This could remind the clinicians of the importance of insulin treatment in the potential drug-to-drug interactions in the diabetic patients.

Effects of propofol on functional activities of hepatic and extrahepatic conjugation enzyme systems

The effect of propofol on the hepatic and extrahepatic conjugation enzyme systems was assessed in vitro using microsomal and cytosolic preparations of human liver, hamster kidney, lung and gut. The functional activities of phase-II enzymes, including uridine diphosphate-glucuronosyltransferase (UDPGT), glutathione S-transferase (GST) and N-acetyltransferase (NAT) were evaluated in the presence of various concentrations of propofol (0.05-1.0 mmol litre-1), using 1-naphthol, 1-chloro-2,4-dinitrobenzene and p-aminobenzoic acid as substrates respectively. Propofol produced concentration-dependent inhibition of UDPGT activity in human liver microsomes. Propofol did not produce significant inhibition of human hepatic GST activity at concentrations below 1.0 mmol litre-1. In contrast, NAT activity was unaffected by propofol 0.05-1.0 mmol litre-1 in human liver cytosolic preparations. In extrahepatic tissues, hamster renal and intestinal UDPGT activities were significantly inhibited by propofol at 0.25-1.0 mmol litre-1. In these tissues, GST and NAT were unaffected by propofol at 1.0 mmol litre-1. Propofol produced differential inhibition of human liver and hamster extrahepatic conjugation enzymes as a result of different substrate and tissue specificities. The potential interference of the metabolic profile of phase-II enzymes as a result of inhibition by propofol (especially of UDPGT and GST) should be considered when using propofol with other drugs for anaesthesia.

Schedule to inject in vitro matured oocytes may increase pregnancy after intracytoplasmic sperm injection

To ascertain the value of using immature oocytes in an intracytoplasmic sperm injection (ICSI) program, the authors designed a schedule, at 5 p.m. on day 1 (the day of oocyte retrieval) and at 8 a.m. and 2 p.m. on day 2, to recognize and inject the in vitro matured (IVM) oocytes. For the 1,166 oocytes retrieved in 107 ICSI cycles, 128 (11.0%) were at the stage of metaphase I (MI) and 113 (9.7%) at germinal vesicle. Routine ICSI for metaphase 11 oocytes was performed at 2 p.m. on day 1 (initial ICSI). In culture medium of human tubal fluid with 15% maternal serum, 85.1% (205/241) immature oocytes progressed to maturation in which 16.4% (21/128) of MI oocytes matured at 5 p.m. of day 1. The rate of normal fertilization for IVM oocytes (58.5%) was not significantly different from that of initial ICSI (64.0%). One patient received a transfer of two fertilized IVM oocytes alone that were injected at 5 p.m. of day 1, maturing from the MI stage, and achieved a normal pregnancy. The fertilized IVM oocytes were replaced along with the embryos from initial ICSI for 40 cycles that led to 14 (35%) clinical pregnancies. In 43 fertilized IVM oocytes donated for research, we observed that cleavage (95.3%) to the 2- to 4-cell stage was not distinct from that of initial ICSI (94.6%); however, the percentage of embryos of grade I and II morphology was significantly smaller (24.4% vs. 62.5%). Only five (11.6%) developed to blastocysts in vitro. Twenty-one fertilized IVM oocytes were frozen for future transfer. A schedule to inject IVM oocytes in ICSI cycles may generate more accessible embryos for fresh transfer or cryopreservation to increase the chance of pregnancy, although the embryo quality was relatively poor.

Molecular basis for the polymerization of octopus lens S-crystallin

S-Crystallin from octopus lens has a tertiary structure similar to sigma-class glutathione transferase (GST). However, after isolation from the lenses, S-crystallin was found to aggregate more easily than sigma-GST. In vitro experiments showed that the lens S-crystallin can be polymerized and finally denatured at increasing concentration of urea or guanidinium chloride (GdmCl). In the intermediate concentrations of urea or GdmCl, the polymerized form of S-crystallin is aggregated, as manifested by the increase in light scattering and precipitation of the protein. There is a delay time for the initiation of polymerization. Both the delay time and rate of polymerization depend on the protein concentration. The native protein showed a maximum fluorescence emission spectrum at 341 nm. The GdmCl-denatured protein exhibited two fluorescence maxima at 310 nm and 358 nm, respectively, whereas the urea-denatured protein showed a fluorescence peak at 358 nm with a small peak at 310 nm. The fluorescence intensity was quenched. Monomers, dimers, trimers, and polymers of the native protein were observed by negative-stain electron microscopic analysis. The aggregated form, however, showed irregular structure. The aggregate was solubilized in high concentrations of urea or GdmCl. The redissolved denatured protein showed an identical fluorescence spectrum to the protein solution that was directly denatured with high concentrations of urea or GdmCl. The denatured protein was readily refolded to its native state by diluting with buffer solution. The fluorescence spectrum of the renatured protein solution was similar to that of the native form. The phase diagrams for the S-crystallin in urea and GdmCl were constructed. Both salt concentration and pH value of the solution affect the polymerization rate, suggesting the participation of ionic interactions in the polymerization. Comparison of the molecular models of the S-crystallin and sigma-GST suggests that an extra ion-pair between Asp-101 and Arg-14 in S-crystallin contributes to stabilizing the protomer. Furthermore, the molecular surface of S-crystallin has a protruding Lys-208 on one side and a complementary patch of aspartate residues (Asp-90, Asp-94, Asp-101, Asp-102, Asp-179, and Asp-180) on the other side. We propose a molecular model for the S-crystallin polymer in vivo, which involves side-by-side associations of Lys-208 from one protomer and the aspartate patch from another protomer that allows the formation of a polymeric structure spontaneously into a liquid crystal structure in the lens.

Evaluation of a capacitance method for direct antifungal susceptibility testing of yeasts in positive blood cultures

The feasibility of using a capacitance method (CM) for direct antifungal susceptibility testing of yeasts in positive blood cultures was evaluated. The CM used the same test conditions as those recommended by the National Committee for Clinical Laboratory Standards. After direct inoculation of positive culture broths into module wells (Bactometer; bioMérieux, Inc., Hazelwood, Mo.), the end-point determination was made by monitoring the capacitance change in the culture broths with Bactometer. The MIC of amphotericin B was the lowest concentration at which yeast growth was completely inhibited, while the MICs of ketoconazole, flucytosine, and fluconazole were the concentrations at which a >/=80% reduction in capacitance change was observed. The MICs of the four drugs against each blood isolate obtained on subculture plates were also determined by the macrodilution method. For 51 positive blood cultures tested, the percent agreement (+/-2 log(2) dilutions) between the CM and the macrodilution method were as follows: amphotericin B (98%), ketoconazole (92%), flucytosine (84%), and fluconazole (96%). The CM was further used for breakpoint susceptibility testing of fluconazole (8 and 64 microg/ml) and flucytosine (4 and 32 microg/ml) against yeasts in positive blood cultures. After testing of 74 specimens by the CM, flucytosine and fluconazole produced one (1.4%) major error and two (2.8%) minor errors, respectively. All yeasts that displayed resistance to flucytosine or fluconazole were detected within 24 h after direct inoculation of the positive broths into Bactometer. The CM may be useful for the rapid detection of antifungal resistance in positive blood cultures containing yeasts.

Modulation of cytochrome P-450 dependent monooxygenases in streptozotocin-induced diabetic hamster: I. Effects of propofol on defluorination and cytochrome P-450 activities

BACKGROUND

Diabetes mellitus could induce polymorphic alterations of metabolic activities of cytochrome P-450 dependent monooxygenases in chemical-induced diabetic animals. The purpose of this study is to define the functional impact of clinical concentrations of propofol on the metabolic activities of cytochrome P-450 in the diabetic animals.

METHODS

In order to validate the effect of propofol on cytochrome P-450 activities, especially the cytochrome P-450 2E1 and its defluorination activity, we applied NADPH-generating system to measure the metabolizing activities of cytochrome P-450 isozymes of streptozotocin-induced diabetic hamsters within the microsomes preincubated with various concentrations of propofol. The extent of defluorination and activity of cytochrome P-450 2E1 were assessed by reacting the propofol-treated microsomes in NADPH-generating system with enflurane and aniline as substrates respectively. Drug metabolizing activities of cytochrome 1A1, 2B1, and 3A4 were evaluated by metabolizing specific substrates, benzo(a)pyrene, pentoxyresorufin and erythromycin, within the microsomes of diabetic hamsters preincubated with various concentrations of propofol.

RESULTS

The hepatic and renal defluorination of enflurane was significantly inhibited by 0.05 and 0.10 mM propofol in the microsomes of diabetic hamster (P < 0.05). The activities of aniline hydroxylase (cytochrome 2E1), pentoxyresorufin O-dealkylase (cytochrome 2B1) and benzo(a)pyrene hydroxylase (cytochrome 1A1) were inhibited by propofol in a concentration-dependent manner from 0.05 to 0.10 mM. However, propofol showed no significant effect to the erythromycin N-demethylase (cytochrome 3A4) at its concentration of 0.05-0.10 mM in the diabetic hamsters.

CONCLUSIONS

Our data demonstrated that propofol in therapeutic concentrations of 0.05 and 0.10 mM, could inhibit both liver and kidney defluorination and cytochrome P-450's activities of the diabetic hamsters in vitro of different extent. This should remind clinicians of propofol's potential drug-to-drug interactions in the diabetic patients.

Analysis of soy isoflavone conjugation in vitro and in human blood using liquid chromatography-mass spectrometry

Soybean products containing isoflavones are widely consumed in Western and Asian diets for putative health benefits, but adverse effects are also possible. The conjugated forms of isoflavones present in a soy nutritional supplement (predominately acetyl glucosides) and in blood from two human volunteers after consuming the supplement (7- and 4'-glucuronides and sulfates) were identified using liquid chromatography coupled with electrospray/tandem mass spectrometry. Circulating conjugates of genistein and daidzein were quantified using selective enzymatic hydrolysis and deuterated internal standards for liquid chromatography-electrospray/mass spectrometry. The levels of isoflavone glucuronides were much greater than the corresponding sulfates or aglycones. The substrate activities of genistein and daidzein were evaluated with recombinant human UDP glucuronosyl transferase (UGT) and sulfotransferase (SULT) by using enzyme kinetics. The SULTs 1A1*2, 1E, and 2A1 catalyzed formation of a single genistein sulfate; however, SULTs 1A2*1 and 1A3 had no observed activity. None of the SULTs showed activity with daidzein. Although several UGTs (1A1, 1A4, 1A6, 1A7, 1A9, and 1A10) catalyzed 7- and 4'-glucuronidation of genistein or daidzein, the UGT 1A10 isoform, which is found in human colon but not liver, was found to be specific for genistein. Glucuronidation of only genistein was observed in human colon microsomes, although nearly equal activity was observed for daidzein in human liver and kidney microsomes. These findings suggest a prominent role for glucuronidation of genistein in the intestine concomitant with absorption, although hepatic glucuronidation of absorbed genistein and daidzein aglycones is also likely.

An in vitro monitoring system for simulated thermal process in cryosurgery

This paper describes a new in vitro experimental model that records temperature changes over a culture plate, which then can be used to assess the biological effects of cryosurgery. A cryoprobe and 16 thermocouples set up by a computer control system were used to monitor the temperature changes during freezing and thawing in a culture plate, and the data were used to create a temperature profile of the entire plate. Location of the thermocouples was confirmed by a digital camera viewing from under the plate, and temperature changes at any point in the interpolated areas were estimated using a curve fitting method. The estimated temperature was checked by sampling with four additional randomly placed thermocouples. Linear regression analysis showed that the estimated temperature and measured temperature were very close (correlation coefficients 0.98-0.99). MBT-2 tumor cells were cultured and then subjected to simulated cryosurgery. The surviving cells were stained with crystal violet and the cell death boundary was detected by image processing. Temperature history at the cell death boundary was retrieved and analyzed. With this system it is possible to recreate the temperature changes that result in a certain biological effect (such as cell death) during the process of simulated cryosurgery.

Oligosaccharides from Hoya carnosa

Oligosaccharides A, B, and C (1-3, respectively) were isolated from the stem of Hoya carnosa. Their structures were established by NMR and chemical methods. Compounds 1 and 2 were 6-deoxy-3-O-methyl-beta-allopyranosyl(1-->4)-beta-cymaropyranosyl( 1-- >4)-beta-cymaropyranosyl(1-->4)-beta-cymaronic acid delta-lactone and 6-deoxy-3-O-methyl-beta-allopyranosyl(1-->4)-beta-oleandropyranosyl++ +(1 -->4)-beta-cymaropyranosyl(1-->4)-beta-cymaronic acid delta-lactone, respectively. Compound 3 was the sodium salt of 2.

Inactivation of Coprinus cinereus peroxidase by 4-chloroaniline during turnover: comparison with horseradish peroxidase and bovine lactoperoxidase

The peroxidase from Coprinus cinereus (CPX) catalyzed oxidative oligomerization of 4-chloroaniline (4-CA) forming several products: N-(4-chlorophenyl)-benzoquinone monoamine (dimer D), 4,4'-dichloroazobenzene (dimer E); 2-(4-chloroanilino)-N-(4-chlorophenyl)-benzoquinone (trimer F); 2-amino-5-chlorobenzoquinone-di-4-chloroanil (trimer G); 2-(4-chloroanilino)-5-hydroxybenzoquinone-di-4-chloroanil (tetramer H) and 2-amino-5-(-4-chlroanilino)-benzoquinone-di-4-chloroanil (tetramer 1). In the presence of 4-CA and H2O2, CPX was irreversibly inactivated within 10 min. Inactivation of CPX in the presence of H2O2 was a time-dependent, first-order process when the concentration of 4-CA was varied between 0 and 2.5 mM. The apparent dissociation constant (Ki) for CPX and 4-CA was 0.71 mM. The pseudo-first order rate constant for inactivation (k(inact)), was 1.15 x 10(-2) s(-1). Covalent incorporation of 20 mole 14C-4-CA per mole of inactivated CPX was observed. The partition ratio was about 2200 when either 4-CA or H2O2 was used as the limiting substrate. These results show that 4-CA is a metabolically activated inactivator (i.e. a suicide substrate). Unmodified heme and hydroxymethyl heme were isolated from native, 4-CA-inactivated and H2O2-incubated CPX. Inactivation resulted in significant losses in both heme contents. Analysis of tryptic peptides from 4-CA-inactivated CPX by MALDI-TOF/ MS and UV-VIS spectrophotometry suggested that trimer G and tetramer H were the major 4-CA derivatives that were covalently bound, including to a peptide (MGDAGF-SPDEVVDLLAAHSLASQEGLNSAIFR) containing the heme binding site. These studies show that heme destruction and covalent modification of the polypeptide chain are both important for the inactivation of CPX. These results were compared with similar studies on 4-CA-inactivated horseradish peroxidase (HRP) and bovine lactoperoxidase (LPO) during the oxidation of 4-CA.

The crystal structure of a T cell receptor in complex with peptide and MHC class II

The crystal structure of a complex involving the D10 T cell receptor (TCR), 16-residue foreign peptide antigen, and the I-Ak self major histocompatibility complex (MHC) class II molecule is reported at 3.2 angstrom resolution. The D10 TCR is oriented in an orthogonal mode relative to its peptide-MHC (pMHC) ligand, necessitated by the amino-terminal extension of peptide residues projecting from the MHC class II antigen-binding groove as part of a mini beta sheet. Consequently, the disposition of D10 complementarity-determining region loops is altered relative to that of most pMHCI-specific TCRs; the latter TCRs assume a diagonal orientation, although with substantial variability. Peptide recognition, which involves P-1 to P8 residues, is dominated by the Valpha domain, which also binds to the class II MHC beta1 helix. That docking is limited to one segment of MHC-bound peptide offers an explanation for epitope recognition and altered peptide ligand effects, suggests a structural basis for alloreactivity, and illustrates how bacterial superantigens can span the TCR-pMHCII surface.

Inhibitory effect of mimosine on proliferation of human lung cancer cells is mediated by multiple mechanisms

The plant amino acid mimosine has been reported to block cell cycle progression in the late G1 phase. A recent study showed that mimosine might induce growth arrest by activating the expression of p21CIP1, a cyclin-dependent kinase inhibitor (CDKI), and by inhibiting the activity of cyclin E-associated kinases in human breast cancer cells. However, mimosine at higher concentrations also blocked proliferation of p21-/- cells by unknown mechanisms. In this study, we investigated the effect of mimosine on the expression of cyclins and CDKIs in human lung cancer cells. We found that mimosine specifically inhibited cyclin D1 expression in H226 cells. The expression of another G1 cyclin, cyclin E, was not regulated by mimosine in all lung cancer cell lines examined. Moreover, mimosine induced p21CIP1 expression in H226 and H358 cells, while it activated p27KIP1 expression in H322 cells. However, mimosine does not affect transcription of these genes directly because significant changes in cyclin D1 or CDKI expression were observed at 12-24 h after drug addition. Our results indicate that mimosine may block cell proliferation by multiple mechanisms and this amino acid is a useful agent for the study of cell cycle control.

Differential induction of androgen receptor transactivation by different androgen receptor coactivators in human prostate cancer DU145 cells

Recently identified androgen receptor (AR) coactivators were used in this study to determine whether the specificity of sex hormones and antiandrogens could be modulated at the coactivator level. We found that ARA70 is the best coactivator to confer the androgenic activity on 17beta-estradiol. Only ARA70 and ARA55 could increase significantly the androgenic activity of hydroxyflutamide, a widely used antiand rogen for the treatment of prostate cancer. None of the AR coactivators we tested could significantly confer androgenic activity on progesterone and glucocorticoid at their physiological concentrations (1-10nM). We also found that ARA70, ARA55, and ARA54, but not steroid receptor coactivator-1 (SRC-1) and Rb, could significantly enhance the delta5-androstenediol-mediated AR transactivation. Furthermore, in comparing the relative specificity of these coactivators to AR in DU145 cells, our results suggested that ARA70 has a relatively higher specificity and that SRC-1 can enhance almost equally well many other steroid receptors. Finally, our data demonstrated that AR itself and some select AR coactivators such as ARA70 or ARA54 could, respectively, interact with CBP and p300/CBP-associated factors that have histone acetyl-transferase activity for assisting chromatin remodeling. Together, our data suggest that the specificity of sex hormones and antiandrogens can be modulated by some selective AR coactivators. These findings may not only help us to better understand the specificity of the sex hormones and antiandrogens, but also facilitate the development of better antiandrogens to fight the androgen-related diseases, such as prostate cancer.

Suppression of Delta(5)-androstenediol-induced androgen receptor transactivation by selective steroids in human prostate cancer cells

Our earlier report suggested that androst-5-ene-3beta,7beta-diol (Delta(5)-androstenediol or Adiol) is a natural hormone with androgenic activity and that two potent antiandrogens, hydroxyflutamide (Eulexin) and bicalutamide (Casodex), fail to block completely the Adiol-induced androgen receptor (AR) transactivation in prostate cancer cells. Here, we report the development of a reporter assay to screen several selective steroids with anti-Adiol activity. Among 22 derivatives/metabolites of dehydroepiandrosterone, we found 4 steroids [no. 4, 1,3,5(10)-estratriene-17alpha-ethynyl-3, 17beta-diol; no. 6, 17alpha-ethynyl-androstene-diol; no. 8, 3beta, 17beta-dihydroxy-androst-5-ene-16-one; and no. 10, 3beta-methylcarbonate-androst-5-ene-7,17-dione] that have no androgenic activity and could also block the Adiol-induced AR transactivation in prostate cancer PC-3 cells. Interestingly, these compounds, in combination with hydroxyflutamide, further suppressed the Adiol-induced AR transactivation. Reporter assays further showed that these four anti-Adiol steroids have relatively lower glucocorticoid, progesterone, and estrogenic activity. Together, these data suggest some selective steroids might have anti-Adiol activity, which may have potential clinical application in the battle against the androgen-dependent prostate cancer growth.

Expression, purification, and functional analysis of murine ectodomain fragments of CD8alphaalpha and CD8alphabeta dimers

Soluble mouse CD8alphaalpha and CD8alphabeta dimers corresponding to the paired ectodomains (CD8(f)) or their respective component Ig-like domains (CD8) were expressed in Chinese hamster ovary cells or the glycosylation variant Lec3.2.8.1 cells as secreted proteins using a leucine zipper strategy. The affinity of CD8alphaalpha(f) for H-2K(b) as measured by BIAcore revealed a approximately 65 microM K(d), similar to that of CD8alphabeta(f). Consistent with this result, CD8alphaalpha(f) as well as CD8alphabeta(f) blocked the effector function of N15 T cell receptor transgenic cytolytic T cells in a comparable, dose-dependent fashion. Furthermore, both Lec3.2.8.1-produced and Chinese hamster ovary-produced CD8 homodimers and heterodimers were active in the inhibition assay. These results suggest that the Ig-like domains of CD8 molecules are themselves sufficient to block the requisite transmembrane CD8-pMHC interaction between cytolytic T lymphocytes and target cells. Moreover, given the similarities in co-receptor affinities for pMHC, the findings suggest that the greater efficiency of CD8alphabeta versus CD8alphaalpha co-receptor function on T cells is linked to differences within their membrane-bound stalk regions and/or intracellular segments. As recently shown for sCD8alphaalpha, the yield, purity and homogeneity of the deglycosylated protein resulting from this expression system is sufficient for crystallization and x-ray diffraction at atomic resolution.

Cyst-like chylous coagulum in the urinary bladder of a patient with recurrent chyluria

We report a rare case of recurrent chyluria in a 64-year-old man, who had undergone sclerosing therapy for chyluria with complete remission 40 years previously. The chyluria recurred 4 months before the present hospital admission. The patient presented with acute urine retention and weight loss of 6 kg during the past 6 months. Urine biochemistry studies showed elevated concentrations of albumin (0.7 g/dL), globulin (0.6 g/dL), cholesterol (0.59 mmol/L), and triglyceride (0.89 mmol/L), confirming the diagnosis of chyluria. Intravenous urography showed a substantial filling defect in the urinary bladder. Cystoscopy revealed milky urine flowing out of the right ureteral orifice, and a large chylous coagulum presenting as a cyst-like mass in the urinary bladder. The chyluria was successfully treated with sclerosing therapy with injection of 76% Urografin (Shering AG, Berlin, Germany) into the right upper urinary tract, and the chylous coagulum was evacuated endoscopically. No evidence of chyluria recurrence has been noted during a year of follow-up, and the patient has regained 6 kg of body weight. This particular presentation of chylous coagulum in a chyluria patient has not been previously reported in the literature.

Risk factors for prostate carcinoma in Taiwan: a case-control study in a Chinese population

BACKGROUND

Although prostate carcinoma remains a rare disease among Chinese men, its incidence is on the rise. The authors conducted a hospital-based case-control study to identify risk factors for prostate carcinoma in northern Taiwan.

METHODS

Patients at a selected veterans hospital or 2 military hospitals who were newly diagnosed with prostate carcinoma between August 1995 and July 1996 were included as cases (n = 90). Controls (n = 180) were comprised noncancer patients who were treated in emergency rooms and departments other than those of urology and cardiology at the same hospitals; controls were matched to cases by age (+/-5 years) and admission date (+/-4 months). Subjects were interviewed in person to elicit information regarding sociodemographic characteristics, life-style, diet, height, and weight.

RESULTS

Cases and controls were similar in terms of age and the majority of sociodemographic characteristics. However, cases tended to have received more education and were less likely to have blue-collar jobs than controls. The consumption of pork was moderately higher for cases than for controls, although this difference was not statistically significant. Cases were more likely than controls to engage in exercise (odds ratio [OR] = 2.16; 95% confidence interval [CI] = 1.18-3.96) and to have a body mass index > or = 24.75 kg/m2 at ages 40-45 years (OR = 2.00; 95%CI = 1.05-3.82). In addition, cases were less likely to cook vegetables with pork lard (OR = 0.47; 95%CI = 0.24-0.91).

CONCLUSIONS

The higher frequency of exercise and lower use of pork lard for cooking among cases reported in the current study suggest that cases tended to have relatively affluent life-styles compared with controls. Because less affluent families are likely to consume more vegetables than meat, these preliminary findings indicate that vegetable intake appears to have a protective effect.

Contents of constituents in mature and immature fruits of evodia species

A total of 33 commercial samples of Evodiae fructus originated from the rutaceous plants Evodia rutaecarpa (Juss.) Benth. and E. rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang (= E. officinalis Dode), respectively, were collected from Taiwan's herbal market. The contents of eighteen constituents (including 15 alkaloids, 2 flavonoids and 1 diterpenoid) in these samples were determined by high-performance liquid chromatography within 60 minutes. Analysis results showed that the constituent contents were almost unrelated to the species, but rather closely related to the degrees of maturity of the fruit. Those fruits with open mouths and unsplit ovaries had the highest total contents, fruits with open mouths and split ovaries had lower contents, and fruits with closed mouths had the lowest contents. In terms of the individual constituents, the open-mouth fruits contained higher contents of dehydroevodiamine, evodiamine, evocarpine and rutaecarpine, whereas the closed-mouth fruits had higher contents of dehydroevodiamine, epimedoside C, evocarpine and evodiamine.