Determination of dextromethorphan and its metabolite dextrorphan in human urine by capillary gas chromatography without derivatization

A sensitive, simple and accurate method was developed for determination of dextromethorphan (DM) and dextrorphan (DT) in human urine by capillary gas chromatography without derivatization. After an oral dose of 30 mg DM, urine samples were collected and extracted, then analyzed on 0.22 mmx17 m HP-1 capillary column. DM and its metabolite DT were analyzed simultaneously with good separation. Docosane was used as the internal standard (I.S.). The detector used was flame ionization detector (FID). There was a linear relationship between peak area ratios of analytes to I.S. and concentration of analytes over the concentration range 0.37-7.38 micromol/l for DM and 0.39-77.8 micromol/l for DT. The recovery was 88.1 approximately 103.9% for DM and 86.7 approximately 96.8% for DT. The within-day and between-day coefficients of variation were less than 7.4 and 7.3% (RSD) for the assay of DM and DT in urine, respectively. The limits of detection (LOD) were 0.30 micromol/l for DM and 0.16 micromol/l for DT. The limits of quantitation (LOQ) were 0.37 micromol/l (RSD<6%) for DM and 0.39 micromol/l (RSD<7%) for DT. The method has been applied to determine the oxidative phenotypes of cytochrome P450 2D6 (CYP2D6) in a Chinese population with metabolic ratio of DM in human urine.

Pressure and temperature changes in heat-cured acrylic resin during processing

OBJECTIVES

The aims of this study were to measure the pressure and temperature changes of acrylic resin during processing, to record the highest temperature reached when fast cured in boiling water and to determine the elevated boiling point of monomer under high pressure.

METHODS

A subminiature pressure transducer (temperature compensated to 94 degrees C) and a thermocouple were placed on the palate of a standardized maxillary complete denture base. A heat-cured resin (Trevalon C) was polymerized by a long heating cycle (72 degrees C for 6.5 h and 92 degrees C for 1.5 h). Recordings of pressure and temperature (n=6) were made at initial clamping of denture flasks and throughout the processing cycles of resin. The temperature of the resin was also monitored during a fast cycle, which was accomplished by placing the flask directly into boiling water for 40 min.

RESULTS

The pressure of acrylic dough inside the clamped flask was initially 11.5 atm (SD=3.2) and reached a peak of 22.0 atm (SD=3.5) during the long heating cycle. The elevated boiling point of monomer at increased pressure was calculated to be about 193 degrees C (at 11.5 atm) and 228 degrees C (at 22.0 atm). These elevated boiling points are higher than the maximum temperature 131 degrees C (SD=6.6) reached during the fast curing cycle. No porosity was observed even in the denture bases heat-cured by the fast cycle.

SIGNIFICANCE

The highest temperature reached by heating of resin during processing is well below the elevated boiling point of monomer. Monomer therefore does not boil in clamped denture flasks under sufficient pressure. Thus adequate clamp pressure prevents gaseous porosity irrespective of curing cycle used.

Measurement issues in screening outstanding teachers

Measurement issues that arise in a two-stage teacher evaluation for an outstanding faculty award are addressed. A teacher evaluation inventory with ten Likert-type items was developed. Thirty college teachers were rated by 293 students on the new inventory. The facet Rasch technique was applied to analyze the test data, and the items fit the Rasch models fairly well. The separation reliability for the teachers is.98, indicating that the items together with these students can differentiate the teachers extremely well. A cut score was set to.80 logits so that only those teachers with efficacy estimates above that level are eligible to apply for the award. A short version containing only half of the items was also developed.

Vitrification of mouse oocytes using closed pulled straws (CPS) achieves a high survival and preserves good patterns of meiotic spindles, compared with conventional straws, open pulled straws (OPS) and grids

BACKGROUND

We modified the loading of pulled straws into a new closed system, called closed pulled straws (CPS) for holding oocytes for vitrification. The morphological survival, dynamics of meiotic spindles, and fertilization in vitro of vitrified oocytes using CPS were compared with conventional straws, open pulled straws (OPS), and grids.

METHODS

Surviving oocytes were stained for spindles and chromosomes after 1, 2 and 3 h incubations, and compared with controls. The capacity of fertilization and embryonic cleavage were examined in vitro.

RESULTS

The survival rates of the CPS (79%) and straw (77%) groups were significantly higher (P < 0.05) than the OPS (63%) and grid (39%) groups. At a 1h incubation, vitrified oocytes of four groups had significantly fewer normal spindles than controls (P < 0.05). The straw group was inferior to the others in spindle morphology (P < 0.05). After a 3 h incubation, recovery of vitrified oocytes with normal spindles was significantly improved in all groups (P < 0.05). The percentages of fertilization and blastocyst formation of vitrified oocytes after a 1 h incubation was significantly lower than controls (P < 0.05), but they were improved after 2 or 3 h incubations (P < 0.05).

CONCLUSIONS

Oocytes vitrified using CPS, OPS or grids could lessen spindle injuries and expedite recuperation. The survival using OPS or grids is lower. Sufficient culture time for recovery of meiotic spindle would be imperative for fertilization events of vitrified oocytes. CPS has the advantages of achieving a high survival and preserving good spindles.

Risk factors of catheter-related infections in total parenteral nutrition catheterization

BACKGROUND

The use of central venous catheter for administration of total parenteral nutrition (TPN) is a risk factor of catheter-related infections (CRIs) that are associated with increased morbidity and mortality, prolonged hospitalization, and increased medical costs. The purpose of this study is to evaluate the risk factors of CRIs in patients with administration of TPN.

METHODS

A total of 1134 patients receiving TPN between January, 1996 and December, 1998 were studied. The category of infection included definite catheter-related bloodstream infection (CR-BSI), probable CR-BSI, and insertion site infection. Statistical analysis of risk factors was performed.

RESULTS

A total of 131 episodes of CRI occurred, representing an infection rate of 11.46%. Ninety-three episodes (8.1%) had probable CR-BSI, 13 episodes (1.1%) had definite CR-BSI, and 25 episodes (2.2%) had insertion site infection. Duration of TPN infusion and frequency of catheter insertion showed statistically significant difference by logistic regression multivariate analysis. The isolated organisms were in sequence of coagulase-negative Staphylococci (19.4%), Staphylococcus aureus (17.2%) and Candida albicans (14.4%).

CONCLUSIONS

Risk factors influencing the occurrence of CRI in TPN administration were multifactorial; however, duration of TPN infusion and frequency of catheter insertion were the main factors in our study.

Fabrication of complete denture bases reinforced with polyethylene woven fabric

Incorporation of 5 layers of woven, high-modulus polyethylene fiber into acrylic resin denture bases produces substantial improvements in mechanical properties and dimensional changes. A modified split-pack technique has been developed using conventional dental-laboratory compression molding to accommodate multiple layers of woven fabric in complete denture bases. A recess formed in the resin by a spacer allows the reinforcement to be embedded in the denture base without exposing the fibers. Embedded fibers do not compromise the esthetics of complete dentures.

Analysis of breast milk to assess exposure to chlorinated contaminants in Kazakhstan: sources of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposures in an agricultural region of southern Kazakhstan

High levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; up to 208 pg/g fat) were measured in samples of breast milk collected in 1997 from 64 donors [41 first-time mothers (primiparae)] living on state farms in southern Kazakhstan. TCDD was the major contributor (70%) to the toxic equivalents, matching the congener patterns found in breast milk and serum samples collected in 1994 and 1996 from donors in nearby villages. The highest TCDD levels were found in state farms adjacent to a reservoir (zone A), which receives agricultural runoff from cotton fields. TCDD levels in zone A were significantly higher than levels in a region more distant (zone B; > 10 miles) from the reservoir (zone A: mean 53 pg/g, n = 17; zone B: mean 21 pg/g, n = 24; p = 0.0017). Levels of TCDD in breast milk and animal-derived foodstuffs were 10 times U.S. levels. Body burden and dietary data suggest that exposures to TCDD are chronic, environmental, and long term and may be related to the use of chemicals in cotton agriculture. The data suggest that the most likely source is the use of cotton defoliants contaminated with TCDD, and the most likely pathway for human exposure is via the consumption of contaminated foodstuffs.

Denture base reinforcement using woven polyethylene fiber

Reinforcement of acrylic denture base resin with high-performance polyethylene fiber in woven form produced a substantial improvement of stiffness and impact strength, as well as reducing the sensitivity of the material to notches that mimic anatomic features. The mechanical properties of the new systems were not affected by water immersion. Reinforced complete maxillary and mandibular dentures having good appearance and satisfactory fiber/resin integration were achieved using conventional laboratory techniques. These prostheses are undergoing clinical trials with encouraging results.

[The effect of RET's group learning program on irrational beliefs and health condition of the elderly]

This study was to explore the effect of RET's group learning program on improving irrational beliefs and the health condition of the elderly people. There were three major purposes: (1) design a set of group learning programs which are suitable for the native elderly; (2) explore the treatment effect of group learning program on improving their irrational beliefs and health; and verify the effect of the group learning program; and (3) explore the follow-up effect of the group learning program on their rational beliefs and health. The subjects were 51 elderly (66-80 years old), divided into treatment group A (Taiwanese), treatment group B (Mandarin) and control group. There were 17 subjects in each group. Instruments used in the study were the irrational Belief Scale, the Mental Health Scale, and the Life Satisfaction Scale, the Coping Strategies Scale, the Disease Checklist and Symptom Checklist. After pretesting treatment groups A and B were instructed in the group learning program twelve times in a period of six weeks. Then the treatment groups were given the post-test with the same instruments. After another six weeks, all subjects were given a follow-up tests. Data were analyzed by dependent sample t-test, repeated measure two-way ANOVA and one-way ANOVA. The main finding were as follow: 1. treatment effect (1) After the treatment of the group learning program, the elderly in groups A and B had a significant improvement (P < .001) with 14 items for irrational belief, mental health, life satisfaction, coping strategies, physical disease and physical symptom. (2) The difference of treatment effect between treatment groups was not significant (P > .05). This result shows that the language mode in which the learning program was presented was not a significant factor. 2. follow-up effect The 12 items of irrational belief, mental health, physical disease, and physical symptoms of the treatment groups were significantly better than in the control group except the factor of reproaching badness. There was no difference among the three groups in life satisfaction and coping strategies. This study affirmed the effect of the group learning program on improving irrational beliefs and health condition of the elderly.

Polyethylene fibre reinforced poly(methylmethacrylate)--water sorption and dimensional changes during immersion

The reinforcement of acrylic denture base resin with high performance polyethylene fibre in chopped, woven and continuous parallel forms resulted in significant reductions in water sorption and dimensional changes during immersion. The dimensional changes during immersion mainly occur during the non-steady state of the diffusion process.

Processing shrinkage of heat-curing acrylic resin reinforced with high-performance polyethylene fibre

The incorporation of high-performance polyethylene fibre into acrylic denture-base resin produced a very significant decrease in the processing shrinkage of the material, explained by the highly anisotropic mechanical and thermal properties of the fibres.

Acrylic resin reinforced with chopped high performance polyethylene fiber--properties and denture construction

A newly developed incremental mixing technique has been used to incorporate over 30 vol % chopped high performance polyethylene fiber into acrylic denture base resin. The reinforcement produced a substantial improvement in several clinically important properties, namely: 1) stiffness and impact strength were higher; 2) the mechanical properties were insensitive to notches that mimic anatomical features; and 3) samples damaged during bending and impact did not break up into separate fragments. Reinforced complete maxillary and mandibular dentures of good esthetic appearance were successfully manufactured and polished with conventional laboratory techniques.

[Effect of Salvia miltiorrhiza on the cardial ischemia in rats induced by ligation]

I.p. injection (5 g crude drug/kg) of water extract of Salvia miltiorrhiza to S.D. rats can prevent the acute cardial ischemia induced by the ligation of the coronary artery. The elevation of S-T segment in the electrocardiogram caused by the ischemia was greatly reduced in animals treated with Salvia miltiorrhiza compared with control group. The ischemia area in the left ventricle was significantly reduced and survival rate of the rats increased.

[Protective action of Salvia miltiorrhiza aqueous extract on chemically induced acute myocardial ischemia in rats]

Aqueous extract of Salvia miltiorrhiza (SM-H) can protect the acute myocardial ischemia and arrhythmia of Sprague-Dawley rats induced by isoproterenol (ISO) or BaCl2 with the following results: (1) intraperitoneal injection (i.p.) of SM-H for 3 to 5 days or intravenously (i.v.) just once significantly reduced the death rate of the animals, (2) i.v. SM-H pretreatment significantly increased the lethal dose of BaCl2 infusion, (3) i.p. SM-H significantly decreased premature ventricular contraction, ventricular fibrillation, bradycardia and mortality rate induced by bolus i.v. of BaCl2, and (4) i.p. SM-H also significantly reduced ECG J-point displacement of rats induced by ISO.

Optical generation of a circular harmonic filter for rotation and translation invariant optical pattern recognition

A new method to generate a circular harmonic filter with both rotation and translation invariance is described, which is based on a phase-shifted double-exposure (PSDE) technique. An expression for the peak correlation intensity at the origin of the correlation plane as a function of target orientation for the PSDE filter is derived. Experimental results confirming the theoretical predictions are provided.