Analysis of the cytochrome c oxidase subunit II (COX2) gene in giant panda, Ailuropoda melanoleuca.

The giant panda, Ailuropoda melanoleuca (Ursidae), has a unique bamboo-based diet; however, this low-energy intake has been sufficient to maintain the metabolic processes of this species since the fourth ice age. As mitochondria are the main sites for energy metabolism in animals, the protein-coding genes involved in mitochondrial respiratory chains, particularly cytochrome c oxidase subunit II (COX2), which is the rate-limiting enzyme in electron transfer, could play an important role in giant panda metabolism. Therefore, the present study aimed to isolate, sequence, and analyze the COX2 DNA from individuals kept at the Giant Panda Protection and Research Center, China, and compare these sequences with those of the other Ursidae family members. Multiple sequence alignment showed that the COX2 gene had three point mutations that defined three haplotypes, with 60% of the sequences corresponding to haplotype I. The neutrality tests revealed that the COX2 gene was conserved throughout evolution, and the maximum likelihood phylogenetic analysis, using homologous sequences from other Ursidae species, showed clustering of the COX2 sequences of giant pandas, suggesting that this gene evolved differently in them.

High dose rate afterloading intraluminal brachytherapy in malignant airway obstruction of lung cancer.

PURPOSE: This is a retrospective study to review the palliation rate, survival rate and complications of high dose rate (HDR) intraluminal brachytherapy in the treatment of malignant airway obstruction of lung cancer. METHODS AND MATERIALS: A total of 225 high dose rate (HDR) brachytherapy treatments were delivered to 76 patients with symptomatic malignant airway obstruction by remote afterloading technique. An average of 7 Gy at a radius of 1 cm from the center of the source was delivered by Iridium-192 (Ir-192) sources. The majority of the patients received 3 fractions at 2 week intervals. Fifty-four patients received HDR brachytherapy as part of their initial treatment; 20 patients presented as symptomatic endobronchial recurrence. Two patients received YAG laser photoresection to open up the obstruction to allow insertion of the brachytherapy catheter. Fifty-nine patients received concurrent external beam irradiation. Forty-two patients were given 60-70 Gy in 6-7 weeks with curative intent. Seventeen patients were given 20-59 Gy in 2-5 weeks as a palliative measure. Nine patients received a radiosensitizer. One patient received concurrent chemotherapy. RESULTS: The symptomatic response rates are as follows: dyspnea had an 87% response rate (59% partial response, 28% complete response), cough had a 79% response rate (47% partial response, 32% complete response), hemoptysis had a 95% response rate (38% partial response, 57% complete response), and postobstructive pneumonia had an 88% response rate (53% partial response, 35% complete response). Sixty-six patients had follow up endoscopic examination (1-3 months after brachytherapy). Their total response rate was 87% (52% partial response and 35% complete response). There were four acute complications: three cases of massive hemoptysis and one of mild hemoptysis. There are five late complications: three cases of radiation pneumonitis and two of esophagitis. At the time of this study, 55 patients have died with the maximum survival duration 113 months (9.4 years) from diagnosis date and 18 months from first HDR treatment. Twenty-one patients are still alive with a mean follow-up duration of 20 months from diagnosis date and 7.8 months from the first HDR treatment. CONCLUSION: HDR brachytherapy is an excellent modality for palliating symptomatic malignant airway obstruction with an acceptable complication rate; however, no definitive increase of survival rate was observed. Prospective clinical trials are needed to better define its merit regarding survival. This paper also includes a literature review and discussion of HDR brachytherapy on bronchogenic cancer.

The measurement of trabecular bone mineral density using coherent and Compton scattered photons in vitro.

A photon scattering method for measuring the trabecular bone mineral density (TBMD) in vitro is described. This method involves the measurement of the ratio of coherent to Compton 90 degrees scattered photons from Am-241 by using a narrow beam geometry with an intrinsic germanium detector. The feasibility of using smaller scattering angles for better counting efficiency and the associated problems in their application for in-vivo measurements were investigated. Calibration of the system with fresh trabecular bone samples showed a linear relationship between the coherent to Compton ratio R of the detected counts and the TBMD (r = 0.94). The effect of the overlying soft tissue on the R ratio was significant while the effect of self-attenuation by the trabecular bone itself and the cortical layer was negligible. It was found that the marrow fat content could alter the value of the R ratio. Our results show that for a 10% increase in the fat content in the interstices of the trabecular bone there is a 2.5% decrease in the R ratio. This technique together with soft tissue corrections will enable us to measure the TBMD of the calcaneum in vivo, assuming a small variation in the trabecular fat content. The estimated absorbed dose to the bone marrow is about 139 mrad.

[Allele specific amplification for CYP2D6 gene related to intermediate metabolizer in Chinese subjects].

AIM: To establish an allele specific PCR amplification (ASA-PCR) for determination of the genotype of CYP2D6* 10B polymorphism in Chinese subjects. METHODS: CYP2D6* 10B alleles of 65 healthy Chinese subjects were analyzed by a two-step PCR assay and the correlation of genotype and phenotype was studied. RESULTS: There were 20 CYP2D6* 10B heterozygous genotypes subjects (wt/m) in 35 very extensive metabolizers (VEMs), which consisted the major part of VEM subjects (57%). Meanwhile, 20 subjects consisting 69% of 29 intermediate metabolizers were CYP2D6* 10B homozygous mutant genotypes (m/m). The poor metabolizer was also m/m. The metabolic ratio of CYP2D6* 10B m/m subjects were larger than wt/m and wild type, the values were -1.49 +/- 0.54, -2.20 +/- 0.49 and -2.47 +/- 0.61 (P < 0.01). CONCLUSION: PCR-ASA was shown to be a rapid and specific method. It can be used to study the genetic polymorphism, especially CYP2D6 intermediate metabolism.

[Determination of caffeine metabolite for the evaluation of N-acetyltransferase, CYP1A2 and xanthine oxidase activities].

Caffeine was used as a metabolic probe to measure, in 120 healthy volunteers, the activities of three enzymes, deduced to be N-acetyltransferase(NAT2), CYP1A2 and xanthine oxidase (XO). The caffeine metabolites of 5-acetylamino-6-formylamino-3-methyluracil (AFMU), 1-methylxanthine(1X), 1-methyluric acid(1U), 1, 7-dimethylxanthine(17X), and 1, 7-dimethyluric acid(17U) in urine were determined with HPLC after 4-5 hours of caffeine drink. The ratios of AFMU/1X or AFMU/(AFMU + 1X + 1U), (AFMU + 1X + 1U)/17X or (AFMU + 1X + 1U)/17U, and 1U/1X or 1U/(1X + 1U) were used as the index of NAT2, CYP1A2, and XO activities respectively. Frequency distribution analysis of the metabolic ratios of NAT2 indicated two distinct group with 20 slow acetylators and 100 rapid acetylators. Similar CYP1A2 activity was found in Chinese compared with European volunteers. Frequency analysis of CYP1A2 indicated the log normal distribution in 120 Chinese. The CYP1A2 index was much higher in smokers than that in nonsmokers. But no obvious difference was observed between young and old volunteers. The XO index also showed log normal distribution and has the similar value compared with European volunteers. The concentration variations of 1X and 1U in young volunteers were much lower than that in old volunteers.

[Effects erythropoietin on experimental anemia in rats with chronic renal failure].

Erythropoietin (EPO) is a glycoprotein hormone secreted by human kidney cells. Human EPO was induced from human embryo kidney cells, isolated and purified from medium by biochemical method in our laboratory. The hypoproliferative anemia in chronic renal failure (CRF) has been assumed to be the result of decreased EPO production by the damaged kidney and of the shortening of the survival of erythrocytes. In this study, CRF anemia was formed 9 weeks after the removal of five-sixths of the renal mass of rats. These anemic rats were divided into 6 groups: treated with different dosages of EPO or physiological saline. The results indicate that EPO has apparent effects on anemia in rats with CRF. It may stimulate erythropoiesis and improve the anemia state of rats with CRF. Hematological parameters (RBC, Hb, PLT, Ht and Rt) may be reverted to normal levels (P less than 0.001). The level of BUN and Cr were significantly decreased. The optimum dose of EPO was 1000 U/kg. All these results show that injection of EPO has therapeutic effect on anemia in rats with CRF. EPO showed no effect on normal rats.

[Analysis of population pharmacokinetics with NONMEM in clinical patients treated with amikacin by intravenous infusion].

Clinical data (n = 275) collected from 52 patients with respiratory tract infection receiving amikacin (AMK) by intravenous infusion were analysed with NONMEM, a computer program designed for estimating population pharmacokinetic parameters. Concentrations of AMK in serum were determined by fluorescence polarization immunoassay (FPIA). A two compartment open model was used for analysing AMK population pharmacokinetics. The influence of body weight (BW), creatinine clearance (CC), administration history (HIS) and state of pathology (chronic obstructional pulmonary disease, COPD) on pharmacokinetics was investigated. The pharmacokinetic parameters of AMK were shown to be influenced by creatinine clearance (CC) and COPD.

Comparative bioavailability study of a generic sustained release diclofenac sodium tablet.

The bioavailability of a generic diclofenac sodium sustained release tablet preparation (Zolterol, SR) was compared with the innovator product, Voltaren, SR. Twelve healthy adult male volunteers participated in the study, which was conducted according to a randomized, two-way crossover design with a wash out period of one week. The bioavailability of diclofenac was compared using the parameters area under the plasma concentration-time curve (AUC(0-infinity)), peak plasma concentration (Cmax) and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed for both logarithmically transformed AUC(0-infinity), Cmax values and Tmax value of the two preparations.

[Determination of simvastatin in human plasma by high performance liquid chromatography].

Simvastatin is widely used in the treatment of hypercholestero-lemia. Recently, it was reported that it is also effective in reducing lethality in coronary heart disease. A simple and sensitive reversed-phase liquid chromatographic method has been developed and validated for the analysis of simvastatin in human plasma. Simvastatin and internal standard lovastatin in plasma were extracted with cyclohexane-dichloromethane (3.5:1, V/V), and then measured by HPLC using a Lichrospher C18 column as stationary phase and an acetonitrile-water (70:30, V/V) mixture as mobile phase. The flow rate was 1.2 mL/min. Simvastatin was quantified by UV at 237 nm. The calibration curve showed a good linearity in the mass concentration range of 0.25-50.0 micrograms/L. The regression equation is: Y = 0.0364 rho + 0.00583, r = 0.9998. Intra-day and inter-day coefficients of variation of assay for simvastatin in plasma < 7.94% and < 8.58%, respectively. The recoveries of simvastatin were > 93.3%. The method has been used to determine simvastatin in plasma from 12 healthy male volunteers.

Pharmacokinetics of ofloxacin through three administration routes.

This paper reports the pharmacokinetic characteristics of ofloxacin (Ofl) through 3 administration routes in 42 patients with respiratory tract infections. The concentration-time data were fitted with a two-compartment model for infusion (inf) and im, and a one-compartment model for po. The pharmacokinetic parameters of Ofl through inf, im and po were: T1/2 beta or T1/2K 6.0 +/- 1.3, 5.0 +/- 1.0, and 5.0 +/- 0.7 h; Vc or Vd 58 +/- 16, 68 +/- 27 and 94 +/- 25 L; Cmax 3.9 +/- 1.0, 2.8 +/- 0.9, and 1.9 +/- 0.7 micrograms.ml-1; AUC 16 +/- 5, 15 +/- 4, and 15 +/- 4 h.micrograms.ml-1; Cl 13 +/- 4, 14 +/- 4, and 14 +/- 3 L.h-1, respectively.

Pharmacokinetics of theophylline metabolites in 8 Chinese patients.

AIM: To study theophylline metabolites pharmacokinetics in patients after a therapeutic dose. METHODS: Eight adult patients with mild bronchial asthma and normal liver function were infused aminophylline intravenously (6.6 mumol.kg-1). The plasma concentrations of theophylline and its 4 metabolites: 1,3-dimethyluric acid (DMUA), 3-methylxanthine (3-MX), 1-methyluric acid (MUA), and the intermediate 1-methylxanthine (1-MX) were monitored by HPLC throughout 24 h. RESULTS: The plasma concentration of DMUA was the highest one among the 4 metabolites. 3-MX showed the slowest elimination rate. The plasma concentration of 1-MX throughout a 24-h period showed that there was a picking up of 1-MX (from 0.04 mumol.L-1 to 1.05 mumol.L-1) in the next morning. CONCLUSION: The formation of DMUA was the main metabolites. During night there was an accumulation of 1-MX.

Simultaneous modeling of pharmacokinetics and pharmacodynamics of propafenone in healthy subjects.

AIM: To study the simultaneous modeling of pharmacokinetics and pharmacodynamics (PK-PD) of propafenone (Pro) in healthy subjects. METHODS: Ten healthy Chinese volunteers, 5 extensive metabolizers (EM) and 5 intermediate metabolizers (IM) of CYP2D6, received a single dose (400 mg) of Pro hydrochloride. The blood samples and electrocardiogram (ECG) measurements were taken after administration over 15 h period. The concentrations of Pro in plasma were measured by a reverse-phase HPLC. PR interval was used as an average value of 10 PR interval measurements. RESULTS: There was a delay between Pro level and percentage of PR interval prolongation. After PK-PD simulating, the relationship between effect concentration (Ce) and the effect met the sigmoid E(max) model. CYP2D6 (EM & IM) played an important role in both pharmacokinetics and pharmacodynamics which produced by Pro. The AUC (microg . h . L-1) of IM group was significantly higher than that of EM group (5126 +/- 1030 vs 2948 +/- 1230, P < 0.05). Whereas Ce50 (microg/L) was also greater in IM group than in EM group (747 +/- 281 vs 359 +/- 123, P < 0.05). On the other hand, gamma of EM group was about one fold larger than that of IM group (P < 0.05). CONCLUSION: CYP2D6 phenotype of human may influence not only pharmacokinetic of Pro but also its pharmacological effects.

Genetic analysis of N-acetyltransferase polymorphism in a Chinese population.

AIM: To study the genetic basis of N-acetylatransferase polymorphism in Chinese. METHODS: Genotypes in 120 healthy Han volunteers from 19 provinces of China were assayed. The 3 common mutant alleles (M1, M2, M3) and one normal wild-type (WT) allele of the N-acetyltransferase (NAT2) gene were detected by allele-specific polymerase chain reaction technique. RESULTS: The NAT2 allele frequencies in 120 Chinese (WT = 0.625, M1 = 0.0458, M2 = 0.188, M3 = 0.142) were different (P < 0.01). The NAT2 genotype distribution for all detected combinations of NAT2 alleles in 120 Chinese subjects was consisitent with Hardy-Weinberg equilibrium (chi 2 = 7.27, nu = 8, 0.7 > P > 0.5). Fifty subjects (41.7%) were homozygous wildtypes, 50 subjects (41.7%) were heterozygous mutants, and 20 subjects (16.7%) were homozygous mutants. CONCLUSION: The lower frequency of mutant M1 allele compared with that of Caucasians explains the low frequency of slow acylators in Chinese.