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Amphetamine intoxication in dogs referred to the Veterinary Diagnostic Laboratory or the Veterinary Hospital of the University of Minnesota was characterized by excitement, agitation, hyperthermia, and convulsive episodes that could be confused with other convulsant poisonings. Extraction procedures on stomach contents or urine enabled indentification of the drug, using ultraviolet spectrophotometry.
OBJECTIVE: To investigate the relationship between the dissolution rate and bioavailability of paracetamol tablets. METHODS: The dissolution rate of paracetamol tablet was determined according to methods described in the Pharmacopoeia of the People's Republic of China. Ultraviolet spectrophotometry was employed to measure urine concentration of paracetamol, and the relative bioavailability was determined in 25 male healthy volunteers, with the relationship between the dissolution rate and bioavailability of paracetamol assessed. RESULTS: The 15-min dissolution rates of 5 kinds of paracetamol tablets were 100.43+/-2.61, 99.76+/-1.97, 96.47+/-3.52, 89.58+/-1.85, and 85.85+/-1.83 respectively, with their bioavailability of 86.34+/-10.06, 85.82+/-11.21, 87.10+/-10.86, 81.71+/-12.34, and 76.53+/-11.73 respectively, showing obvious linear relationship between them, which conformed to the equation y = 0.6122x + 25.175, r = 0.9642. CONCLUSION: As there is a good linear relationship between the dissolution rate and bioavailability of paracetamol tablets, the latter parameter can be derived from the measurement of the former.
OBJECTIVES: To investigate the effect of aging on the expression of nitric oxide synthase I (NOS I) and the activity of nitric oxide synthase in the rat penis. METHODS: Thirty male rats from three age groups(adult, old and senescent) were investigated: 1. The expressions of NOS I protein and mRNA in the penis were detected by Western blot and RT-PCR, respectively. 2. NOS activity in the penis was detected with ultraviolet spectrophotometry. RESULTS: In rats of the old and the senescent groups, the expression of NOS I protein decreased significantly as compared to that of the adult group. NOS I mRNA expression was well related to its protein expression. NOS activity had no statistical difference between the adult group and the old group, but it reduced significantly in the senescent group as compared to that of the adult group(P < 0.01). CONCLUSIONS: It is maybe one of the main mechanisms of erectile dysfunction in the aging male that the aging causes the decreases of NOS I protein and mRNA expression and NOS activity.
AIM: To investigate the effect of aging on the expression of nitric oxide synthase I (NOS I) and the activity of NOS in rat penis. METHODS: Sixty male rats from 3 age groups (adult, old and senescent) were investigated. The expression of NOS I protein and mRNA in rat penis were detected by Western blot and RT-PCR respectively and the NOS activity, with ultraviolet spectrophotometry. RESULTS: In the old and senescent group, NOS I protein expression was significantly decreased as compared with the adult. NOS I mRNA expression was well correlated with the protein expression. NOS activity was not statistically different between the adult and old groups, but it was significantly reduced in the senescent compared with the adult group (P<0.01). CONCLUSION: The aging-induced decreases in NOS I expression and NOS activity may be one of the main mechanisms leading to erectile dysfunction in the senescent rats.
In this paper, we study the enzyme catalysis reaction kinetics that 2,3-diaminophenazine compound was synthesized with the horseradish peroxidase catalyzing reaction of H2O2 oxidizing o-phenylemediamine. First, the product of oxidation of o-phenylenediamine (OPD) by H2O2 catalyzed and by horseradish peroxidase (HRP) was synthesized. The finest reaction conditions (acid degree, temperature, OPD, H2O2, HRP various molar ratio) were selected. The reaction conditions and the product were determined by UV-absorption spectrum, IR and element analysis. The results showed that the product is 2,3-diaminophenazine. Secondly, the reaction order of OPD-H2O2-HRP system and the rate constant were studied by using ultraviolet spectrophotometry based on Michaelis-Menten equation. The finest conditions lambda max = 446.3 nm, pH = 4.85, t = 22 degrees C were selected, a series experiments were done. Experimental results showed that this is an one reactant reaction determined by the experiment and theory, and derived K(m) = 6.02 x 10(-3) mol.L-1 and upsilon m = 7.2 x 10(-2) delta A.min-1.
The study describes a dysmorphic newborn infant with life-threating anomaly, later diagnosed as trisomy 18, mimicking Smith-Lemli-Opitz syndrome in the immediate neonatal period. The establishment of the correct diagnosis in the first days of life is very important for the decision-making process, because trisomy 18 has a poor prognosis, and treatment is not instituted, whereas cholesterol supplementation may be of benefit to patients with Smith-Lemli-Opitz syndrome. Ultraviolet spectrophotometry showed very easy and rapid method for differentiation of both syndromes, where gas chromatography/mass spectrometry analysis is not available. (Fig. 2, Ref: 18.)
BACKGROUND & OBJECTIVE: 5-Fluorouracil (5-FU) belongs to antimetabolic anticancer drugs and its half-life time in vivo is only about 5 minutes. Continuous infusion (48 hours,72 hours,28 days) was commonly used to maintain long-time steady-state concentration (Css). So it is necessary to exploit new slow-release system for 5-FU. This article was designed to investigate the preparation technique,shape characteristics, and drug releasing characteristics in vivo of 5-FU loaded core-shell type nanoparticles which were made by biodegradable amphiphlic poly (ethylene glycol)-poly (gamma-benzyl-L-glutamate)(PEG-PBLG). METHODS: The PEG-PBLG nano-micelles were prepared by diafiltration method. Its morphology was observed by transmission electron microscopy and scan electron microscopy. Encapsulating efficiency of 5-FU was determined by ultraviolet spectrophotometry. The 5-FU releasing characteristics from nano-micelles in vivo were investigated by high-performance liquid chromatography (HPLC). RESULTS: 5-FU loaded PEG-PBLG copolymer nano-micelles (5-FU/PEG-PBLG) was of round or ellipsic shape. The diameter of the micelles was 180-250 nm; the size of drug storeroom was about 200 nm and the thickness of hydrophilic zone was about 30 nm. The entrapment efficiency was (29.5+/-0.015)%. In control group, 5-FU is one-compartment in vivo; its half-life was 5.3 minutes; the maximum plasma concentration (C(max)) was 17047.3 microg/L; T(max) was the time of attaining C(max) of the end of infusion; the area under the plasma concentration-time curve (AUC) was 6263.7 microg/L x min. However, the model of nano-micelles in vivo was typical release-drug of nano-micelles namely abrupt release-slow release; its t(1/2) was 63.2 minutes; C(max) was 4563.5 microg/L; T(max) was 1.25 hours; AUC was 5794.5 microg/Lxmin. Compared with 5-FU preparation, T(max) of 5-FU/PEG-PBLG was longer (P< 0.01);C(max) was lower (P< 0.01);t(1/2) was longer (P< 0.01); AUC was similar (P >0.01). CONCLUSION: The 5-FU/PEG-PBLG nano-micelles can change the pharmacokinetics of 5-FU, prolonging the circulation time in vivo and make a slow release.
OBJECTIVE: To determine the total content of alkaloids from Rhizoma coptidis in the traditional Chinese medicine prescription Gegenqinlian. METHODS: The extract of Gegenqinlian decoction and powder of the minipills were respectively purified with alumina column chromatography, and the total alkaloid content of Rhizoma coptidis in these preparations was determined using ultraviolet spectrophotometry at 350 nm. RESULTS: The total alkaloid content was 32.4 mg/g in the aqueous extract of Gegenqinlian decoction and 19.6 mg/g in Gegenqinlian minipills, with a recovery rate of 98.1% (RSD=2.9%). CONCLUSION: The method we employed yields accurate and stable results with much sensitivity for quality control of Gegenqinlian minipills, and also provides reference for study of Gegenqinlian prescription and other prescriptions that contain Rhizoma coptidis.
Deoxynivalenol (DON) obtained from 2 commercial sources was characterized, and its purity was determined. The structural identity of DON was confirmed by 1H and 13C-nuclear magnetic resonance (NMR) spectroscopy, gas chromatography with mass spectrometric (GC/MS) detection, and infrared/attenuated total reflectance (IR/ATR) spectroscopy. NMR spectra showed shifts that varied from previously published data. However, we established a complete, unambiguous assignment for all signals. Chromatograms obtained by GC/MS were almost identical for both investigated samples and confirmed the structure of DON. Likewise, IR/ATR spectra verified the identity of DON. The degree of purity was determined by liquid chromatography (LC) with a variable wavelength detector, LC/MS/MS, GC with electron-capture detection (GC-ECD), and ultraviolet (UV) spectrophotometry. The purity check using LC showed a single peak in both chromatograms. With LC/MS/MS measurements, we could detect small amounts of impurities in the crystalline DON from both sources. In data obtained by GC-ECD, no differences in purity were observed. The UV measurements showed an absorption maximum at 217 nm. The mean epsilon(m) of the extinction coefficients was calculated as 6727 (L/cm/mol) for DON (Sigma) and 6825 (L/cm/mol) for DON (Biopure). Finally, the purity of DON from the 2 commercial sources was calculated as >96 and >98%, respectively. Although the DON produced by both providers can be considered sufficiently pure for routine analysis of trichothecenes in food and feed, this work again demonstrated that the impurity of the solid mycotoxin constitutes the greatest contribution to the overall uncertainty of a mycotoxin calibrant.
OBJECTIVE: To observe antiasthmatic and anti-inflammatory actions mechanisms of CDCA. METHOD: The content of NO was determined by method of nitroreductase chromatometry in serum and trachea tissue. The content of cAMP was analysed by method of competitive protein-binding assay. The content of PGE2 was determined by method of ultraviolet spectrophotometry. RESULT: CDCA significantly decreased the content of NO of serum and trachea tissue in mice. CDCA increased greatly the content of cAMP of trachea tissue in rats. CDCA significantly decreased the content of PGE2 of trachea and lung tissue in mice. CONCLUSION: Mechanisms of antiasthmatic and anti-inflammatory actions of CDCA are related to increasing the content of cAMP in trachea tissue and decreasing the constituent of NO and PGE2 in body.
One common method of illicit methamphetamine manufacture utilizes an alkali metal, typically lithium, and liquid ammonia to chemically reduce ephedrine or pseudoephedrine to form methamphetamine. This method is often referred to as the lithium-ammonia reduction method or the Birch reduction method. While the hydroxyl group of ephedrine is more reactive than the aromatic ring, excess alkali metal and the presence of a proton source allow the formation of a cyclohexadiene byproduct not found in samples of methamphetamine produced from other manufacturing methods. A sample enriched in this byproduct was generated and characterized using nuclear magnetic resonance (NMR) spectroscopy, gas chromatography-mass spectrometry (GC-MS), infrared (IR) spectrophotometry, and ultraviolet (UV) spectrophotometry. The chemical structure of this byproduct was determined to be 1-(1',4'-cyclohexadienyl)-2-methylaminopropane (CMP).
BACKGROUND: Mucosal immunity is important to defense against dental caries. To enhance mucosal immunity, a DNA vaccine mucosal delivery system was prepared by encapsulating anticaries DNA vaccine (plasmid pGJA-P/VAX) in chitosan under optimal conditions and the characteristics of the microparticles was investigated. Furthermore, the release properties and protective action of microparticles for plasmid were studied in vitro. METHODS: Plasmid loaded chitosan microparticles were prepared by complex coacervation. Three factors, concentration of DNA, sodium sulfate, and the chitosan/DNA ratios in complexes [better expressed as N/P ratio: the number of poly nitrogen (N) per DNA phosphate (P)] influencing preparation were optimized by orthogonal test. The characteristics of microparticles were evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). DNA release rate of microparticles in similar gastro fluid (SGF) or similar intestinal fluid (SIF) at 37 degrees C was determined by ultraviolet spectrophotometry. RESULTS: High encapsulation efficiency (96.8%) was obtained with chitosan microparticles made under optimal conditions of 50 mmol/L Na2SO4, 200 microg/ml DNA and N/P ratio of 4. The size of particles was about 4 to 6 microm. The encapsulation process did not destroy the integrity of DNA. When incubated with SIL, after a release of about 10% in the first 60 minutes, no further DNA was released during the following 180 minutes. When incubated with SGL, the microparticles released a small burst (about 11%) in the first 60 minutes, and then slowly released at a constant, but different rate. CONCLUSIONS: These chitosan microparticles showed suitable characteristics in vitro for mucosal vaccination and are therefore a promising carrier system for DNA vaccine mucosal delivery.
Immobilized copper ion affinity membrane was prepared by using cellulose filter paper as matrix. The membrane was loaded into a chromatographic column designed in the laboratory and the immobilized copper ion affinity membrane chromatographic column was prepared. Hemoglobin (Hb) was adsorbed by the column and its adsorption rate was above 90%. The experimental process was as follows: a set of 5 immobilized copper ion affinity membranes were loaded into a column, uncombined copper ion was removed with 5 mL of sodium phosphate-citric acid buffer (pH 7); the Hb sample volume was 2 mL, and uncombined Hb was eluted with 10 mL of the buffer. The Hb concentration was determined by ultraviolet spectrophotometry at 405 nm. The major influence factors on hemoglobin adsorption rate such as Hb sample amount (1.58-31.6 mg/g (2 mL of sample volume)), pH value range (3.6-10.6), temperature range (25-50 degrees C), and sample flow-rate (0.5-2.5 mL/min) were investigated. The optimal operation conditions were found as follows: the Hb sample amount of 3.16-7.90 mg/g, sample flow-rate of 0.5-1.0 mL/min, test temperature of room temperature, pH value range of 6-8. Compared with aqueous two-phase system, liquid-solid extraction system and the conventional column method, the membrane medium is cheaper and easier to be scaled up.
HYPOTHESIS: Albuterol delivery through a tracheostomy tube is affected by device (nebulizer vs metered-dose inhaler), interface (mask vs T-piece), bias flow, and humidification. METHODS: A lift bar was placed between the chambers of a dual-chambered lung model such that a ventilator triggered simulated spontaneous breathing at a rate of 20 breaths/min, tidal volume of 0.4 L, and inspiratory-expiratory ratio of 1:2. An 8-mm inner diameter cuffed tracheostomy tube was placed through a semi-circular model that simulated a patient's neck. Four conditions of gas flow and humidification were used for the nebulizer experiments: heated aerosol (approximately 30 L/min, approximately 30 degrees C), heated humidity (approximately 30 L/min, approximately 30 degrees C), high flow without added humidity (approximately 30 L/min), or a nebulizer attached to the tracheostomy tube without additional flow. The nebulizer was filled with 4 mL that contained 2.5 mg of albuterol, and operated at 8 L/min. The nebulizer was tested with a T-piece or tracheostomy mask. For the metered-dose inhaler experiments, a spacer was used and actuation of the inhaler (100 microg per actuation) was synchronized with inhalation (4 actuations separated by > or = 15 s). When the spacer was used without additional flow, a valved T-piece was used with a 1-way valve placed either proximal or distal to the spacer. A filter was attached between the lung model and the distal end of the tracheostomy tube. Albuterol washed from the filter was measured by ultraviolet spectrophotometry. RESULTS: For the nebulizer, the most efficient delivery was with no flow other than that to power the nebulizer and with a T-piece (p < 0.001). The most efficient method for aerosol delivery was metered-dose inhaler with a valved T-piece and placement of the 1-way valve in the proximal position (p < 0.001). The effect of humidity was unclear from the results of this study. CONCLUSIONS: Albuterol delivery via tracheostomy was affected by the delivery device (nebulizer vs inhaler), bias gas flow, and the patient interface.
HYPOTHESIS: Albuterol delivered during noninvasive positive-pressure ventilation is affected by use of a nebulizer or metered-dose inhaler (MDI) and whether the leak port is in the hose or the mask. METHODS: A lung model that simulated spontaneous breathing at 20 breaths/min was used. A bi-level positive-airway-pressure ventilator (Respironics S/T30) was set for an inspiratory positive airway pressure of 15 cm H(2)O and an expiratory positive airway pressure of 5 cm H(2)O. The tidal volume delivered was 0.4 L. Two mask types were used: one in which the leak port was incorporated into the circuit, and another in which the leak port was incorporated into the mask. The nebulizer was filled with 4 mL, which contained 5 mg of albuterol, connected via a T-piece directly to the mask, and operated at 8 L/min for 15 min. For the MDI studies, a spacer was placed between the mask and the circuit, and an MDI was actuated into the spacer, either synchronized with the initiation of inhalation or during the exhalation phase (4 actuations separated by \G 15 s in each case). Albuterol was washed from the filter and measured with ultraviolet spectrophotometry. RESULTS: With the nebulizer, significantly more albuterol was delivered to the filter when the leak port was in the circuit (p = 0.001). Significantly more albuterol was delivered with the nebulizer than with the MDI (p < 0.001). The efficiency of albuterol delivery (percent delivered) was similar for nebulizer and MDI with the leak port in the circuit (p = 0.57), but better with the MDI with the leak port in the mask (p = 0.001). Albuterol delivery was significantly less when the MDI was actuated during exhalation (p = 0.001). CONCLUSIONS: Albuterol delivery with noninvasive positive-pressure ventilation was affected by the type of aerosol delivery device, by the location of the leak port, and by actuating the MDI at the proper time in the respiratory cycle.
BACKGROUND & OBJECTIVE: Recently, chitosan, as a nonviral vehicle for transferring DNA molecules into the cells, has attracted much attention because of its cationic properties. This study was to investigate characteristics and transfection activity of chitosan-pDNA microparticles, and confirm the feasibility of chitosan as gene therapy vehicle, which may be employed in further in vivo study. METHODS: Plasmid DNAs were amplified in Eschericha Coli JM109 with transfection of enhanced green fluorescence protein (EGFP) gene, and isolated according to the protocol of Qiagen plasmid midi kit. Chitosan-pDNA microparticles were prepared by the coacervation method, and observed under transmission electronic microscope. In vitro releasing experiment and ultraviolet spectrophotometry were used to measure DNA loading capacity and loading efficiency. The location of pDNA in the microparticles was analyzed by gel retardation assay. Transfection efficiency of chitosan-pDNA microparticles was evaluated by detecting gene expression of EGFP in HEK293 cells after transfection. RESULTS: Chitosan-pDNA microparticles were global, and the size ranged 100-200 nm, with the average of (138 +/- 43) nm. DNA loading capacity and loading efficiency of the microparticles were (46.8 +/- 9.0)% and 100%, respectively. Gel retardation assay confirmed that DNA was wholly encapsulated in the microparticles. In vitro study revealed that the release of DNA from chitosan-pDNA microparticles included two-step process, namely burst effect with a slow second phase. Most of DNA could be released at the time of 48 h. In vitro transfection results indicated that chitosan could efficiently deliver pEGFP into HEK293 cells and stably express green florescence protein. CONCLUSIONS: Chitosan can efficiently transfer target DNA molecules into mammalian cells, continuously release DNA, and stably express DNA. It can be potentially employed as a gene therapy vehicle.
AIM: To study the effect of hyaluronic acid chitosan-based microemulsion (HAC-ME) on the permeability of blood brain barrier( BBB) by using Evans blue (EB) as the indicator. METHODS: A formamide extraction-ultraviolet spectrophotometry method was employed to determine the concentrations of EB in each of the tissues. The in vivo distribution of HAC-ME groups containing EB in mice and the fluorescence intensity and diffusion domain of brain slices were all studied. RESULTS: Contrasting to the common microemulsion (ME), HAC-ME at the lower concentration of HAC (<5 mg x mL(-1)) could further improve the transporting of EB across the BBB while EB concentration in other tissues decreased, and Tmax was delayed about 30 min. CONCLUSION: HAC-ME could facilitate the transporting of EB across the BBB and it was concentration dependent. While the brain targeting absorptive capability of HAC-ME was enhanced.
BACKGROUND & OBJECTIVE: Biodegradable colloidal nano-micelles is a novel targeting drug delivery and controlled release system, which could prolong the biological half-life and lighten the toxicity of chemotherapeutant, meanwhile, present fine biocompatibility. This study was to prepare the biodegradable 5-fluorouracil (5-FU)/DEX-g-PLA nano-micelles, and investigate their killing effect on hepatocarcinoma cell line HepG2 in vitro and in vivo. METHODS: 5-FU/DEX-g-PLA nano-micelles were prepared by 'self-assembly'. Its morphology was observed by transmission electron microscopy. The encapsulating efficiency of 5-FU was determined by ultraviolet spectrophotometry. The in vivo releasing of 5-FU from nano-micelles was investigated by high-performance liquid chromatography (HPLC). The inhibitory effect of 5-FU/DEX-g-PLA on HepG2 cells in vitro was measured by MTT assay. RESULTS: 5-FU/DEX-g-PLA nano-micelles were round or elliptical; the diameter was about 50 nm. The encapsulating efficiency was about 9.3%. The concentration of 5-FU released from 5-FU/DEX-g-PLA nano-micelles was sustained for longer time than that of the naked drug. The in vitro inhibition rate of cell growth was similar in 5-FU/DEX-g-PLA group and naked 5-FU group (58.8% vs. 58.0%, P>0.05); the in vivo inhibition rate of tumor growth was significantly higher in 5-FU/DEX-g-PLA group than in naked 5-FU group (73.1% vs. 57.5%, P<0.05). CONCLUSION: 5-FU/DEX-g-PLA nano-micelles can effectively inhibit the growth of HepG2 cells.