Design and construction of a refrigerator-cooled adiabatic calorimeter for heat capacity measurement in liquid helium temperature region

Heat capacity is a fundamental thermodynamic property of a substance. Although heat capacity values and related thermodynamic functions are available for many materials, low-temperature heat capacity measurements, especially for novel materials, can still provide valuable insights for research in physics, chemistry, thermodynamics, and other fields. Reliable low-temperature heat capacity data are typically measured using classical adiabatic calorimeters, which use liquid helium as the refrigerant to provide a cryogenic environment for heat capacity measurements. However, liquid helium is not only expensive but also not easy to obtain, which greatly limits the application of adiabatic calorimetry. In this work, an accurate adiabatic calorimeter equipped with a Gifford-MacMahon refrigerator was designed and constructed for measuring the heat capacity of condensed matter in the temperature range from 4 to 100 K. The Gifford-MacMahon refrigerator was utilized to provide a stable liquid helium-free cryogenic environment. A simple mechanical thermal switch assembly was designed to facilitate switching between the refrigeration mode and the adiabatic measurement mode of the calorimeter. Based on the measurement results of standard reference materials, the optimized repeatability and accuracy of heat capacity measurements were determined to be within 0.8% and 1.5%, respectively. The heat capacity of α-Fe2O3 nanoparticles was also investigated with this device. Furthermore, this adiabatic calorimeter only requires electricity to operate in the liquid helium temperature range, which may significantly advance the research on low-temperature heat capacity based on adiabatic calorimetry.

Electropolishing influence on biocompatibility of additively manufactured Ti-Nb-Ta-Zr: in vivo and in vitro

Balling defect of the additively manufactured titanium lattice implants easily leads to muscle tissue rejection, which might cause failure of implantation. Electropolishing is widely used in surface polishing of complex components and has potential to deal with the balling defect. However, a clad layer could be formed on the surface of titanium alloy after electropolishing, which may affect the biocompatibility of the metal implants. To manufacture lattice structured β-type Ti-Ni-Ta-Zr (TNTZ) for bio-medical applications, it is necessary to investigate the impact of electropolishing on material biocompatibility. In this study, animal experiments were conducted to investigate the in vivo biocompatibility of the as-printed TNTZ alloy with or without electropolishing; and proteomics technology was used to elaborate the results. The following conclusions were drawn: (a) a 30% oxalic acid electropolishing treatment was effective in solving balling defects, and ~21 nm amorphous clad layer would be formed on the surface of the material after polishing; (b) the electropolished TNTZ suggested decreased cell cytotoxicity and improved blood biocompatibility as compared to as-printed TNTZ; (c) the amorphous clad layer could make a barrier to prevent Ta and Zr ions from penetrating into the muscle tissue, and could form a good tissue regeneration at the implantation site during 4 weeks, indicating that the electropolished TNTZ has the potential as implants; and (d) the cells attached to the electropolished TNTZ showed higher antioxidant capacity but less proliferation than attached to as-printed TNTZ.

Additively manufactured biomedical Ti-Nb-Ta-Zr lattices with tunable Young's modulus: Mechanical property, biocompatibility, and proteomics analysis

Some β-Ti alloys, such as Ti-Nb-Ta-Zr (TNTZ) alloys, exhibit a low Young's modulus and excellent biocompatibility. These alloys are promising new generation biomedical implant materials. Selective laser melting (SLM) can further enable customer-specific manufacturing of β-Ti alloys to satisfy the ever-increasing need for enhanced biomedical products. In this study, we quantitatively determined the relationships between porosity, yield strength, and Young's modulus of SLM-prepared TNTZ lattices. The study constitutes a critical step toward understanding the behavior of the lattice and eventually enables tuning the Young's modulus to match that of human bones. Fatigue properties were also investigated on as-printed lattices in terms of the stress limit. The biocompatibility study included a routine evaluation of the relative cell growth rate and a proteomics analysis using a common mouse fibroblast cell line, L929. The results indicated that the as-printed TNTZ samples exhibited evidence of protein proliferation of the L929 cells, particularly P06733, and that those proteins are responsible for biological processes and molecular functions. They in turn may have promoted cell regeneration, cell motility, and protein binding, which at least partially explains the good biocompatibility of the as-printed TNTZ at the protein level. The study highlights the promising applications of additively manufactured TNTZ as a bone-replacing material from mechanical and biocompatibility perspectives.

[Changes to sleep patterns in young migrants at high altitude]

Objective: To explore the relationship between the level of acclimatization and the changes to sleep architecture in migrants at high altitude. Methods: Nocturnal sleep recordings of 50 subjects aged between 18 and 25 years [mean age (20.9±2.0) years] were analyzed. Those young volunteers were divided into 3 700 m-3 m group(n=10, migrated to an altitude of 3 700 metres for 3 months), 3 700 m-1 y group(n=10, for 1 year) , 5 380 m-3 m group(n=8), 5 380 m-1 y group(n=9), and compared with a control group(n=13, at 1 400 m altitude). Results: When the migrants stayed at 5 380 m for 3 months or 1 year, the wake time increased significantly during sleep[(81.81±59.80)min vs(47.19±24.98) min, P=0.026; (77.94±25.64)min vs(47.19±24.98)min, P=0.040]. Concerning the percentage of total sleep time(TST) in each stage, participants in the 5 380 m-3 m group had a shift in sleep stage distribution with near absence of slow wave sleep(SWS) and a significant increase of N1 , but N2 and rapid eye movement(REM) did not differ. Interestingly, there were entirely concordant changes among the other 3 groups of results, decreased N2 and increased REM. Conclusions: The migrants' abilities to acclimatize themselves to plateau were varied according to the arrived altitude and the length of stay. The sleep of short- time migrants was characterized by increased N1 and decreased SWS, whereas that of well acclimatized migrants was characterized by less N2 and more REM. The efficient recovery in SWS may be an objective reference in high altitude acclimatization.

Effect and mechanism of dihydroartemisinin on proliferation, metastasis and apoptosis of human osteosarcoma cells

Osteosarcoma represents an aggressive type of bone malignancy that poses a significant health threat. The objective of the current study was to analyze the effect and mechanism of dihydroartemisinin (DHA) on the proliferation, metastasis and apoptosis of human osteosarcoma cells. A gradient concentration of DHA (15, 25 and 35 μmol.L-1) was used to stimulate the cells, along with control and Dimethyl sulfoxide (DMSO). The phenotypic outcomes were characterized using MTT assay, clone formation assay, Hoechst 33258 staining assay, luciferase reporter plasmid assay, Western blot and wound healing assay. In addition, IBM SPSS Statistics 18.0 software was applied for statistical analysis and all experimental data were expressed as mean ± s.d. Analysis of variance (ANOVA) was applied to compare the differences among multiple groups. Our results demonstrated that DHA inhibited the proliferation and metastasis of osteosarcoma cells and promoted the apoptosis in the cytomorphosis.

[Analyze on HPLC fingerprint of four main metropolis of herba pogostemonis]

OBJECTIVE

To establish a method for analyzing HPLC fingerprint of Herba pogostemonis and compare the variability of four main producing areas.

METHODS

Diamonsil (R) C18 column was used, the Methanol-0.1% phosphoric acid (gradient elution) as a mobile phase and detection wavelength was set at 254nm, column temperature was 25 degrees C and flow rate was 1.0 ml/min.

RESULTS

There were differences between the HPLC fingerprint of Herba pogostemonis from various places of production. The similarity of Herba Pogostemonis cultivated in tow regions of Zhaoqing Gaoyao and Guangzhou Huangcun was over 90%, and there were more differences among them with Zhanjiang Wuchuan and Hainan Wanning.

CONCLUSION

The method is reliable and accurate. The method can be used for the identification of the crude drug and the evaluation of its quality.

[Seperation and structure elucidation of alkaloids from Chinese drug buzhaye, Folium Microcos]

From the chloroform extracts of the dried Folium Microcos, four compounds were isolated by using repeated column chromatography on silica gel and recrystallization and their structures were elucidated by physicochemical properties and UV, MS and NMR, separately. They are N-methyl-6alpha-(deca-1', 3', 5'-trienyl)-3beta-methoxy-2beta-methylpiperidine, 6-(deca-1', 3', 5'-trienyl)-3-methoxy-2-methylpiperidine, N-methyl-6-(deca-1', 3', 5'-trienyl)-2, 3-dimethylpiperidine and N-methyl-6-(deca-1', 3', 5'-trienyl)-2-methylpiperidine, named as micropiperidine A, micropiperidine B, micropiperidine C and micropiperidine D, respectively. The latter three are new compounds.

Hospital-based management of acute asthmatic exacerbation: an assessment of physicians' behavior in Taiwan

This retrospective study was conducted to assess Taiwanese emergency physicians for their preference in management and adherence to guidelines in treating patients with acute exacerbation of asthma. One hundred twenty patients from hospitals of three different levels were evaluated by reviewing their medical records. Our study revealed that physicians from medical centers and regional hospitals assessed patients more often with arterial blood gas or pulse oximetry; prescribed more doses of beta2-agonist nebulizers; administered more doses of beta2-agonist nebulizers before administering parenteral aminophylline; and prescribed ipratropium nebulizers more often as adjunctive therapy. On the other hand, physicians from district hospitals more frequently prescribed parenteral aminophylline as the first-line medication and more often prescribed only a single dose of beta2-agonist nebulizer. Most emergency physicians in Taiwan did not adhere to guidelines. Specifically, these included omission of peak expiratory flow as the means to assess the severity of asthma exacerbation and response to treatment; suboptimal use of inhaled bronchodilators, such as beta2-agonists and ipratropium; and inappropriate use of parenteral aminophylline as the first-line medication.

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.

[Facial soft tissue three dimensional morphometry]

OBJECTIVE

The purpose of this article were to assess the reproducibility of the landmark locating, and to obtain some facial soft tissue measurements data of the teenagers.

METHODS

8 males were selected to refix the black markers by the same operator and remeasure 14 items by the system, then compare both results. Three dimensional facial morphametry was investigated in a sample of 20 teenagers at the early stage of the permanent dentition.

RESULTS

No item of the remeasurement test showed statistical difference error. The sexual dimorphism was found in the measurements connecting with lower face height(Sn-Pg).

CONCLUSION

It indicated that the landmarks selected in this study had biologic significance and unique definition. The result of teenager facial measurements is in accordance with growth rule.

[Development and application of the facial soft tissue 3D measuring system]

OBJECTIVE

To combine measurement and image technology as an objective means to help prosthodontists provide better service.

METHODS

The system was developed by consisting of two CCD cameras, real time hardware for the recognition of markers and software for the 3D reconstruction.

RESULTS

It allowed efficient, direct and noninvasive calculation of the 3D liner and angular measurements of the human face.

CONCLUSION

This system is a useful way to get 3D information of the human face. It will be a good supplement to the classic cephalometric analyses.

[Validation of the 3D measuring system]

OBJECTIVE

To test the validation of the 3D measuring technique.

METHODS

A life-size plaster cast of human head was used as the anthropomorphic model. Fifteen experimental conditions were studied. Nine linear distances between landmarks and Nasion were measured each time. These were compared to the standard anthropometric measurements using the same landmarks.

RESULTS

The mean difference was 1.21mm (2.09%). Among the 8 conditions imitating different head posture,only the one turning 10 degrees to the left had a significant difference from the normal position.

CONCLUSION

In accordance with the requirements of " human measurement handbook", the system error is acceptable.

[Determination of cinnamaldehyde in Guizhi by HPLC]

OBJECTIVE

To establish a HPLC method for the determination of cinnamaldehyde in Guizhi.

METHOD

Cinnamaldehyde was separated by a Kromasil C18 column (4.6 mm x 200 mm) with a mobile phase of acetonitrile-0.1% phosphoric acid solution(48:52) and an UV detection wavelength of 285 nm.

RESULT

The calibration curve was linear in the range of 0.004-0.02 microliter.ml-1, with a correlation coefficient of 0.9996. The average recovery was 100.7%(n = 5), and RSD 0.3%(n = 6).

CONCLUSION

The method is simple and accurate.

[Improved protoplast-derived plants of Astragalus adsurgens through somatic embryogenesis]

Embryogenic callus was obtained only from hypocotyl explants of Astragalus adsurgens and light inhibited the formation of embryogenic callus. A high yield (1.2 x 10(6)/g F. Wt.) of protoplasts with high viability (over 80%) could be isolated from 10-day-old embryogenic callus. Protoplasts were induced to undergo sustained division and to form cell colonies when cultured in agarose-solidified medium (KMP) containing 1/4 strength of mineral salts and supplemented with 1.5 mg/L 2, 4-D, 0.5 mg/L BA and 0.5 mol/L glucose at a plating density of 1.0 x 10(5)mL, where the plating efficinency was 16.8%. Conditioning medium significantly improved the formation of cell colonies. When protoplast-derived colonies were maintained at 4 degrees C for 2 weeks and subsequently transferred onto medium (MS) with 0.1 mg/L NAA and 1.0 mg/L BA, somatic embryogenesis occurred. Frequency of cell colonies producing somatic embryos reached 70%, and the number of somatic embryos per gram cells was over 200. Cultured on hormone-free half-strength MS medium, somatic embryos developed into healthy plantlets with normal chromosome complement.

Regeneration of Astragalus adsurgens via somatic embryogenesis from cell suspension protoplasts

Protoplasts from 4-day-old embryogenic cell suspension cultures of Astragalus adsurgens, when cultured in KM8P medium which ammonium concentration was reduced to 2.5 mmol/L and supplemented with 0.5 mg/L NAA, 1.0 mg/L 2, 4-D, 0.7 mg/L BA and 0.4 mol/L glucose, underwent cell sustained divisions and formed cell colonies at a frequency of 16%-20%. Preplasmolysis or low temperature treatment of suspension cells prior to enzyme incubation enhanced colony formation. Following proliferation on MS medium containing 1.0 mg/L 2, 4-D and 0.5 mg/L BA, cell colonies were cultured on MS medium containing 0.1 mg/L NAA and 1.0 mg/L BA, where approximately 40% of colonies produced somatic embryos ranging in number from 20 to 40 per colony. No significant decrease was found in the potential of somatic embryogenesis when protoplast colonies were obtained from long-term cell suspensions. On hormone-free 1/2 MS medium, somatic embryos developed into intact plants, which showed normal morphology and stable chromosome number.

Pharmacokinetics of sustained-release capsule of 5-isosorbide mononitrate in 20 healthy Chinese young men

AIM

To compare the pharmacokinetics of domestic and imported sustained-release capsule of 5-isosorbide mononitrate (5-IM).

METHODS

A single and 5-d-repeated oral doses of 5-IM 50 mg were performed on 2 groups of 20 Chinese healthy subjects (10 subjects for each group) in a randomized crossover protocol. The 5-IM in plasma were measured by gas chromatography with electron-captured detector method. Data were analyzed automatically by using a CAPP program on a PC computer.

RESULTS

Fitting the 5-IM concentration-time curves to one-compartment model or following trapezoidal rule, the parameters such as Tmax, Cmax, Ke, MRT, and AUC were calculated and there were no significant differences between the two kinds of capsule. The major pharmacokinetic parameters of domestic and imported 5-IM sustained-release capsule with a 5-d multiple dose were respectively: Cmax (677 +/- 103) and (702 +/- 76) micrograms.L-1; Tmax (5.1 +/- 2.0) and (5.6 +/- 1.3) h; MRT (11.5 +/- 0.5) and (11.4 +/- 0.7) h; AUC0-infinity (12,121 +/- 1346) and (12,352 +/- 988) micrograms.h.L-1. The fraction of drug absorbed in vivo was correlated well with the percentage amount of drug released in vitro at corresponding time (P < 0.05), and the fluctuation indices on d 5 in multiple dose study were not significantly different between the two formulations (P > 0.05). The relative bioavailability of the domestic capsule for single and multiple dose were 96% +/- 11% and 98% +/- 10%, respectively.

CONCLUSION

Domestic 5-IM sustained-release capsule showed bioequivalence compared with the imported capsule and provided the same nitrate-low interval in the latter part of the 24-h dosing interval.

Pharmacokinetics of fluphenazine, a highly lipophilic drug, estimated from a pulse dose of a stable isotopomer in dogs at steady state

The potential utility of a pulse dose of a deuterium-labeled isotopomer (FLU-D(4)) in elucidating the pharmacokinetics of fluphenazine (FLU) at steady state was investigated in dogs. The single-dose oral pharmacokinetics of FLU in dogs were established. After resting the dogs for 3 weeks, the animals were dosed to steady state with oral FLU administered at 12-h intervals. Following 15 doses, one dose of FLU was replaced by a pulse dose of FLU-D(4), after which dosing with FLU was resumed. FLU and FLU-D(4) plasma concentrations were determined by tandem mass spectrometry. Comparable estimates of apparent oral clearance were calculated from (i) a single dose of FLU, (ii) a pulse dose of FLU-D(4), and (iii) over a dosing interval at steady state. Average steady-state plasma concentrations were reliably predictable from a pulse dose of FLU-D(4).

[Research of dynamic measurements of perioral soft tissue]

OBJECTIVE:This article introduced a concept of dynamic image measurement for calculate the quantity of cirumoral soft tissue movements. METHODS: A developed computer image analyzing system was used to calculate the quantity of circumoral soft tissue movement under the three conditions. RESULTS: (1)When/mo/is pronounced,lip protrudes,the upper lip landmarks move upwards,imwards and forwards,and the lower lip landmarks downwards and backwards.The variation of upper lip triangular area will be M2<M3<M1,that of the lower lip will be M3>M2>M1. (2)When/si/is pronounced,as a result of vowel,the amount of lower lip moving down backwards is more than that when/mo/is pronounced,which makes the lower lip triangular area comes to be M3>M2>M1. CONCLUSION: Pronunciation is one of the important oral functins. It could be used as a method of research to measure the facial soft tissue change dynamically and effectively.

The roles of depot injection sites and proximal lymph nodes in the presystemic absorption of fluphenazine decanoate and fluphenazine: ex vivo experiments in rats

PURPOSE

The release and presystemic absorption of fluphenazine and its decanoate ester from intramuscular depots were investigated.

METHODS

Rats were sacrificed in groups of three at various times after injection of drug or prodrug in sesame oil. Muscle tissues at the injection sites and various lymph nodes were excised. Blood (plasma) was harvested by cardiac puncture.

RESULTS

Following administration of fluphenazine decanoate, the amount of prodrug at the sites of injection declined exponentially (half-life 3.4 days). Highest concentrations of drug and prodrug were found in iliac and hypogastric lymph nodes nearest to injection sites in which both analytes were detectable 28 days post dose. The half-life for the decline of fluphenazine from lymph nodes (4.6 days) was similar to that from plasma (4.3 days). Following administration of fluphenazine base, only 2.8% of the dose remained at the sites of injection after 2 days. Concentrations of drug in iliac and hypogastric lymph nodes were comparable to those in distal lymph nodes. Fluphenazine concentrations in the lymphatic tissues decreased at about the same rate as plasma concentrations.

CONCLUSIONS

The rate limiting step appeared to be slow partitioning of the decanoate from oily deposits at the injection site and proximal lymph nodes with subsequent hydrolysis of the ester group.

[Analysis of the measurement on of the maxillofacial soft tissue's parameters association with vertical dimension]

The rehabilitation of vertical dimension of occlusion(VDO) exactly is one of the most important procedure for dental prosthesis in the field of prosthodontics.In this study,total of 19 subjects with normal range occlusion were selected.We measured 33 parameters relating to VDO of their facial soft tissue at intercusping position,with the technique of digital imaging analysis.The results as follows:we established a set of normal values of facial soft tissue parameters,which is suitable for the age group of 21-24 years old.It would provide an objective criterion for the rehabilitation of VDO.Also the normal values in this studies had been compared with other other studies,and it showed that the values of some parameters in our study,such as CH-CH',nasolabial angle were very close to oter data.Furthermore,it was found that both the position of the upper lip and the lower lip of the subjects were more anterior to that of white men,while the degrees of nasolabial and labiomental convexity were less obvious.

[Computer-aided analysis of maxillofacial soft tissue simulating with vertical dimensions of 4 different types]

In this study,33 parameters relating to vertical dimension of occlusion(VDO) of 19 subjects' maxilofacial soft tissue of four different vertical dimentsions(VDs) were measured.All of them were in intercusping position,with the technique of digital imaging analysis.The findings as follows:(1)A set of normal values of facial soft tissue's parameters of four different VDs was established,which was suitable for the age group of 21-24 years old.(2)When the VD was raised to the certain height(H4),it would affect the size of angle of the inferior soft tissue of lip distinctly,furthermore,the correlation analysis showed that there was a positive correlation between the variance of VDs would arouse the change of the inferior soft tissues of lip,especially its size of angle,is very correspondingly and obviously.

[The establishment of the digital imaging analysis system on the lower maxillofacial soft tissue]

Soft tissue shape is an important parameter to evaluate the postprosthetic effect of facial profile.In this study,the technique of digital imaging analysis was used to transferring from imaging informations to digital information,and then these information were imputed to computer for capturing,measuring and analyzing.So far,a set of digital imaging analysis system relating to the speciality of prosthodontics has been established preliminarily,with the advantage of quantitative analysis,non invasion and accuracy.It will provide a new way for reconstructing vertical dimension of occlusion.

Studies on the mechanism of absorption of depot neuroleptics: fluphenazine decanoate in sesame oil

PURPOSE

The purpose of the present study was to investigate the pharmacokinetic characteristics of fluphenazine (FLU) and its decanoate (FLU-D) after intravenous and intramuscular administration to dogs.

METHODS

A group of four beagle dogs was used in all intravenous and intramuscular experiments, with washout periods of no less than three months between doses.

RESULTS

After intravenous FLU-D, the pharmacokinetics of the prodrug (mean +/- SD) were as follows: Clearance (CL) 42.9 +/- 6.3 L/h; terminal half-life (t1/2) 3.5 +/- 0.8 h; volume of distribution (Vd) 216 +/- 61 L. The fractional availability of FLU was 1.0 +/- 0.2. After intravenous FLU, the volume of distribution of FLU (51 +/- 17.8 L) was some 4 fold less than that of the prodrug. Simulations (Stella II) suggested that the rate limiting step was slow formation of FLU from the prodrug in the tissue compartment. After intramuscular FLU-D in sesame oil, the apparent t1/2 of FLU was 9.7 +/- 2.0 days whereas after intramuscular FLU base in sesame oil, the apparent t1/2 was only 7.7 +/- 3.4 h showing that the absorption of FLU itself from the intramuscular site and proximal lymph nodes is relatively rapid.

CONCLUSIONS

The rate limiting step after intramuscular FLU-D appeared to be the slow partitioning of the prodrug out of the sesame oil at the injection site and in proximal lymph nodes.

Pharmacokinetic-pharmacodynamic modeling of metoprolol stereoisomers in spontaneously hypertensive rat

AIM

To study the combined pharmacokinetic-pharmacodynamic (PK-PD) model of metoprolol stereoisomers, and compare their inhibitory effects on cardiovascular system in the spontaneously hypertensive rats (SHR).

METHODS

The drug concentration in plasma was measured by the reversed phase HPLC and the drug effects were recorded by polygraph. The pharmacokinetic parameters and the PK-PD model parameters were calculated.

RESULTS

The plasma concentration-time profiles were adequately described by two-compartment model. Differences of Vd between (+)-Met and (-)-Met were found. The relationships between effects and concentration of effect compartment were represented by the sigmoid-Emax model. The Css50 of Vmax, dp/dtmax, and HR inhibitory effects of (+)-Met were larger than those of (-)-Met.

CONCLUSION

Stereo-selective drug distribution and different potencies of the inhibitory effects of (+)-Met and (-)-Met existed in SHR.

Sensitive method for the simultaneous measurement of fluphenazine decanoate and fluphenazine in plasma by high-performance liquid chromatography with coulometric detection

A highly sensitive and specific high-performance liquid chromatographic method with coulometric detection was developed for the simultaneous assay of fluphenazine decanoate and fluphenazine in plasma. The extraction and sample clean-up procedures are simple, rapid to execute, yet yield chromatograms relatively free of any interference from endogenous plasma constituents, such that the extraordinary sensitivity of the coulometric detector can be exploited fully. This is the first analytical procedure for the simultaneous determination of fluphenazine decanoate and fluphenazine. The detection limits for both fluphenazine decanoate and fluphenazine were 0.1 ng/ml plasma and the limits of quantitation were 0.25 ng/ml plasma. Standard curves from 0.25 to 10 ng/ml were linear with coefficients of variation < 10%. The method was applied to measure plasma levels of fluphenazine decanoate and fluphenazine in patients under medication with 25-50 mg biweekly intramuscular (i.m.) injections of fluphenazine decanoate. It was possible to monitor the plasma levels of fluphenazine in all cases. Fluphenazine decanoate was present in measurable concentration in the plasma of 4 out of 5 patients who received biweekly i.m. injections of 50 mg fluphenazine decanoate. In a pilot experiment with a dog, the method was used to follow fluphenazine decanoate and fluphenazine plasma levels up to 13 days, at least, after i.m. single dose (10 mg/kg).

[Static palatography and image processing system by computer.]

In this study the artificial palates made of black vinyl seat covering the palate and occlusal surfaces of maxillary teeth were coated with white alginate powder and inserted into the mouth of the subjects.After pronunciation of the test sounds,the tongue contact areas on artificial palate were demonstrated by wetting of powder and changing in color from white to black.Thus,photographnys of palatograms were taken.After taking 5 palatogram of each sound,the samples were averaged by an image processor.The averaged outline of each subject's palatogram was converted into a standarized dental arch form,with the gray scale of each image reversed and reduced,and then added to every pattern of the same sound produced by all subjects.Thus,palatograms were based on the frequency of over lapping.From this compiling, contact areas that were common in more than four out of six subjects were extracted.

[The design and application of speech signal processing system by computer in stomatology.]

In this study we established a computer bases on Speech Signal Processing System and changes of formant frequencies of the vowel/i/accompany the changes in the oral cavity after maxillary surgery and prosthodontic reconstruction.The study found the F1 for vowel/i/has no change,while the F2 peak significantly shifted between the preprosthetic and postprosthetic speaking condition after anterior resection of relative energy error value and the speech intelligible measured aurally(P<0.05).

Acute heroin intoxication with complications of acute pulmonary edema, acute renal failure, rhabdomyolysis and lumbosacral plexitis: a case report

After intravenous injection of heroin, a 27-year-old male with altered mental status and hypotension was seen at the Emergency Service where acute pulmonary edema was noted. The problem was resolved three days later after oxygen therapy had been administered by face mask. Acute renal failure, rhabdomyolysis and monoplegia of the patient's left leg were exhibited during his stay at the Intensive Care Unit. Neurological examination and electro-diagnostic studies (electromyography and nerve conduction velocity) showed left lumbosacral plexitis. Hemodialysis was given. Though the patient's hospital course was uneventful, satisfactory recovery from his left leg weakness, which persisted for one year after hospital discharge, was finally achieved.

[A simple method for estimating half-life of drugs obeying Michaelis-Menten elimination kinetics]

AIM

To establish a simple method for estimating half-life of drugs obeying Michaelis-Menten elimination kinetics.

METHODS

A linear relationship is sketched between elimination half-life and drug concentration in blood that obey Michaelis-Menten elimination kinetics. A simple method is proposed to draw a regression line of blood drug concentration vs time after a single bolus intravenous injection.

RESULTS & CONCLUSION

The elimination half-life can be read from the regression line. The method can also be used to estimate the time required for the plasma concentration of a drug to decrease any fraction.

[Evaluation of the tissue-to-blood partition coefficient R for physiological pharmacokinetic models]

The tissue-to-blood partition coefficient R, fraction of drug unbound in blood fB and intrinsic clearance of elimination organ/tissue Cl'L are important parameters used in physiological pharmacokinetic models. Simple equations to evaluate R by AUC were derived in this paper for single bolus iv, the tissue-to-blood partition coefficient of nonelimination organ/tissue was exactly the ratio of AUC between tissue and blood, those equations were examined by the experimental data of rats following iv ethoxybenzamide 20 mg.kg-1, and compared with other methods. Equations to evaluate fBCl'L and other parameters were also given for linear elimination model.