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1.
Huan Jing Ke Xue ; 45(5): 2983-2994, 2024 May 08.
Article in Chinese | MEDLINE | ID: mdl-38629559

ABSTRACT

Taking a city in Guangdong Province as the research area, the concentration and spatial distribution characteristics of heavy metals in the surface soil were studied to clarify the situation of soil heavy metal pollution and priority control factors, providing basic data for the prevention and control of soil heavy metal pollution in the city. The content characteristics of heavy metals in 221 soil samples in the city were analyzed, and the potential health risk assessment and source analysis were carried out through the Monte Carlo model, the potential health risk assessment (HRA) model, and the PMF receptor model. It was found that heavy metals ω(As), ω(Hg), ω(Cd), ω(Pb), ω(Cr), ω(Cu), ω(Ni), and ω(Zn) in the soil of the city were 18.16, 0.43, 1.46, 68.57, 98.34, 64.19, 26.53, and 257.32 mg·kg-1, respectively, with a moderate to high degree of variation. Except for Ni concentration, the soil concentrations of other heavy metal elements exceeded the background values of soil in Guangdong Province to a certain extent, and the concentrations of Cd and Zn exceeded the national secondary standards, resulting in severe heavy metal pollution; the main sources of heavy metals were industrial sources, and natural parent materials, lead battery manufacturing, transportation, artificial cultivation, and pesticide and fertilizer inputs also had an undeniable impact on the accumulation of heavy metals in the soil. Heavy metals in the soil had a certain degree of tolerable carcinogenic health risk for both children and adults, whereas non-carcinogenic risks could be ignored. The potential health risk of children was greater than that of adults, and the main exposure route was through oral intake. The input sources of pesticides and fertilizers and As should be the main controlling factors for the health risks of heavy metals in the city's soil, followed by mixed sources and Cr. There were differences in the spatial distribution characteristics and relative pollution levels of heavy metals, and it is necessary to deepen zoning monitoring and control, strengthen soil pollution prevention and control, and reduce human input of heavy metals in soil.


Subject(s)
Metals, Heavy , Soil Pollutants , Child , Adult , Humans , Environmental Monitoring , Soil , Cadmium/analysis , Soil Pollutants/analysis , Metals, Heavy/analysis , Risk Assessment , China
2.
Huan Jing Ke Xue ; 45(2): 1015-1025, 2024 Feb 08.
Article in Chinese | MEDLINE | ID: mdl-38471939

ABSTRACT

In order to comprehensively study the pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in soils of Guangzhou, 222 topsoil samples were collected and analyzed. The ecological risk of soil PAHs pollution was evaluated using the effect interval low/median method (ERL/ERM) and the (BaP) toxicity equivalent method, and the health risk of soil PAHs pollution was evaluated using the lifelong cancer risk increment model. The source of PAHs was analyzed using the characteristic compound ratio method and PMF model. The results indicated that: the content of surface soil (∑16PAHs) in Guangzhou was 38-11 115 µg·kg-1, with an average of 526 µg·kg-1, and 16 types of polycyclic aromatic hydrocarbon monomers showed strong variation. There was a certain degree of ecological risk of PAHs in Guangzhou, and there was already a significant ecological risk of PAHs pollution in individual sampling points, which were generally in a state of mild pollution. Based on the results of the health risk assessment, the contribution rates of total cancer risk in both adults and children were presented as follows: skin contact > ingestion of soil > respiratory intake. The health risk of children was greater than that of adults, and the overall health risk was within an acceptable range. Source analysis showed that the main sources of soil PAHs in Guangzhou were coal (37.1%); diesel (32%); coking (17.3%); and mixed sources of traffic emissions, biomass combustion, and petrochemical product volatilization (13.6%). The overall source of soil PAHs belonged to mixed sources. The research results have enriched our understanding of the pollution status of PAHs in the surface soil of Guangzhou and are helpful in promoting soil pollution prevention and control actions.


Subject(s)
Neoplasms , Polycyclic Aromatic Hydrocarbons , Soil Pollutants , Child , Adult , Humans , Soil/chemistry , Environmental Monitoring/methods , Polycyclic Aromatic Hydrocarbons/analysis , Soil Pollutants/analysis , Environmental Pollution/analysis , Risk Assessment , China
3.
PLoS One ; 19(1): e0296709, 2024.
Article in English | MEDLINE | ID: mdl-38227590

ABSTRACT

This study examined 70 Klebsiella pneumoniae isolates derived from companion animals with urinary tract infections in Taiwan. Overall, 81% (57/70) of the isolates carried extended-spectrum ß-lactamase (ESBL) and/or plasmid-encoded AmpC (pAmpC) genes. ESBL genes were detected in 19 samples, with blaCTX-M-1, blaCTX-M-9, and blaSHV being the predominant groups. pAmpC genes were detected in 56 isolates, with blaCIT and blaDHA being the predominant groups. Multilocus sequence typing revealed that sequence types (ST)11, ST15, and ST655 were prevalent. wabG, uge, entB, mrkD, and fimH were identified as primary virulence genes. Two isolates demonstrated a hypermucoviscosity phenotype in the string test. Antimicrobial susceptibility testing exhibited high resistance to ß-lactams and fluoroquinolones in ESBL-positive isolates but low resistance to aminoglycosides, sulfonamides, and carbapenems. Isolates carrying pAmpC genes exhibited resistance to penicillin-class ß-lactams. These findings provide valuable insights into the role of K. pneumoniae in the context of the concept of One Health.


Subject(s)
Klebsiella Infections , Urinary Tract Infections , Animals , Klebsiella pneumoniae/genetics , Enterobacteriaceae/genetics , beta-Lactamases/genetics , Bacterial Proteins/genetics , Pets , Anti-Bacterial Agents/pharmacology , beta-Lactams , Urinary Tract Infections/drug therapy , Urinary Tract Infections/veterinary , Urinary Tract Infections/epidemiology , Klebsiella Infections/drug therapy , Klebsiella Infections/veterinary , Microbial Sensitivity Tests
4.
Gerontology ; 69(9): 1076-1094, 2023.
Article in English | MEDLINE | ID: mdl-37348478

ABSTRACT

INTRODUCTION: Attenuating cardiac fibroblasts activation contributes to reducing excessive extracellular matrix deposition and cardiac structural remodeling in hypertensive hearts. Acacetin plays a protective role in doxorubicin-induced cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to investigate the potential molecular mechanisms underlying the protective role of acacetin on hypertension-induced cardiac fibrosis. METHODS: Echocardiography, histopathological methods, and Western blotting techniques were used to evaluate the anti-fibrosis effects in spontaneous hypertensive rat (SHR) which were daily intragastrically administrated with acacetin (10 mg/kg and 20 mg/kg) for 6 weeks. Angiotensin II (Ang II) was used to induce cellular fibrosis in human cardiac fibroblasts (HCFs) in the absence and presence of acacetin treatment for 48 h. RESULTS: Acacetin significantly alleviated hypertension-induced increase in left ventricular (LV) posterior wall thickness and LV mass index in SHR. The expressions of collagen-1, collagen-III, and alpha-smooth muscle actin (α-SMA) were remarkedly decreased after treatment with acacetin (n = 6, p < 0.05). In cultured HCFs, acacetin significantly attenuated Ang II-induced migration and proliferation (n = 6, p < 0.05). Moreover, acacetin substantially inhibited Ang II-induced upregulation of collagen-1 and collagen-III (n = 6, p < 0.05) and downregulated the expression of alpha-SMA in HCFs. Additionally, acacetin decreased the expression of TGF-ß1, p-Smad3/Smad3, and p-AKT and p-mTOR but increased the expression of Smad7 (n = 6, p < 0.05). Further studies found that acacetin inhibited TGF-ß1 agonist SRI and AKT agonist SC79 caused fibrotic effect. CONCLUSION: Acacetin inhibits the hypertension-associated cardiac fibrotic processes through regulating TGF-ß/Smad3, AKT/mTOR signal transduction pathways.


Subject(s)
Cardiomyopathies , Hypertension , Humans , Rats , Animals , Transforming Growth Factor beta1/metabolism , Transforming Growth Factor beta1/pharmacology , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-akt/pharmacology , Myocardium/metabolism , Cardiomyopathies/metabolism , Cardiomyopathies/pathology , Signal Transduction , Collagen/metabolism , Collagen/pharmacology , Collagen Type I/metabolism , Collagen Type I/pharmacology , Hypertension/drug therapy , TOR Serine-Threonine Kinases , Fibroblasts/pathology , Fibrosis
5.
Ann Med ; 55(1): 2193423, 2023 12.
Article in English | MEDLINE | ID: mdl-37183786

ABSTRACT

OBJECTIVE: The objective of this study is to explore the clinicopathological characteristics of gastric cancer and precancerous conditions in patients with primary gastric lymphoma. METHODS: We analyzed 474 cases of primary gastric lymphoma, mainly DLBCL and MALT, from three clinical centres retrospectively, and compared the clinicopathological parameters of primary gastric lymphoma patients complicated with gastric cancer, precancerous conditions, or with no complications. RESULTS: A total of 5.1% of the patients with primary gastric lymphoma were diagnosed with gastric cancer, including metachronous gastric adenocarcinoma (3.2%) and synchronous gastric adenocarcinoma (1.9%). Of the patients with gastric lymphoma, 14.6% had precancerous conditions including atrophy (14.6%), intestinal metaplasia (8.9%), and low-grade intraepithelial neoplasia (1.9%). Primary gastric lymphoma patients with an ulcerative type (p = 0.009) and Lugano classification stage IIE + IV (p < 0.001) lymphoma had a higher risk of complicating with gastric cancers or precancerous conditions. The rate of infection of Helicobacter pylori (Hp) was 68.4% in patients with primary gastric lymphoma, which was higher in patients with MALT lymphoma (p < 0.001), Lugano classification stage I + II (p < 0.001), and patients complicated with precancerous conditions and gastric cancer (p < 0.001), especially gastric cancer of the intestinal type (p = 0.04). Gastric cancer (95.8%) and precancerous conditions (91.3%) occurred mostly in Hp-infected primary gastric lymphoma patients, with a minor subset of Hp-eradicated patients. Primary gastric lymphoma patients had a higher detection rate of early gastric cancer (25.0%) and a five-year survival rate (40.0%) than the general Chinese population. CONCLUSIONS: Patients with primary gastric lymphoma have a high risk of developing gastric cancer and precancerous conditions, and this risk may be related to Helicobacter pylori infection. Follow-up of primary gastric lymphoma provides an opportunity for the detection of early gastric cancer.Key messages5.1% of the patients with primary gastric lymphoma were diagnosed with gastric cancer.14.6% of the patients with gastric lymphoma had premalignant lesions including atrophy (14.6%), intestinal metaplasia (8.9%), and low-grade intraepithelial neoplasia (1.9%).Primary gastric lymphoma patients complicating with gastric cancer had a higher infection rate of Helicobacter pylori (100.0%), a detection rate of early gastric cancer (25.0%) and a five-year survival rate (40.0%) than the general Chinese population.


Subject(s)
Adenocarcinoma , Helicobacter Infections , Helicobacter pylori , Lymphoma, B-Cell, Marginal Zone , Precancerous Conditions , Stomach Neoplasms , Humans , Lymphoma, B-Cell, Marginal Zone/epidemiology , Lymphoma, B-Cell, Marginal Zone/complications , Stomach Neoplasms/epidemiology , Stomach Neoplasms/complications , Retrospective Studies , Helicobacter Infections/complications , Helicobacter Infections/epidemiology , Atrophy/complications , Precancerous Conditions/epidemiology , Precancerous Conditions/complications , Precancerous Conditions/pathology , Metaplasia/epidemiology , Metaplasia/complications
6.
World J Clin Cases ; 10(12): 3720-3728, 2022 Apr 26.
Article in English | MEDLINE | ID: mdl-35647152

ABSTRACT

BACKGROUND: By analyzing the risk factors of postoperative complications in elderly patients with hip replacement, We aimed to develop a nomogram model based on preoperative and intraoperative variables and verified the sensitivity and specificity for risk stratification of postoperative complications in elderly with total hip replacement patients. AIM: To develop a nomogram model for risk stratification of postoperative complications in elderly with total hip replacement patients. METHODS: A total of 414 elderly patients who underwent surgical treatment for total hip replacement hospitalized at the Affiliated Hospital of Guangdong Medical University from March 1, 2017 to August 31, 2019 were included into this study. Univariate and multivariate logistic regression were conducted to identify independent risk factors of postoperative complication in the 414 patients. A nomogram was developed by R software and validated to predict the risk of postoperative complications. RESULTS: Multivariate logistic regression analysis revealed that age (OR = 1.05, 95%CI: 1.00-1.09), renal failure (OR = 0.90, 95%CI: 0.83-0.97), Type 2 diabetes (OR = 1.05, 95%CI: 1.00-1.09), albumin (ALB) (OR = 0.91, 95%CI: 0.83-0.99) were independent risk factors of postoperative complication in elderly patients with hip replacement (P < 0.05). For validation of the nomogram, receive operating characteristic curve revealed that the model predicting postoperative complication in elderly patients with hip replacement was the area under the curve of 0.8254 (95%CI: 0.78-0.87), the slope of the calibration plot was close to 1 and the model passed Hosmer-Lemeshow goodness of fit test (χ 2 = 10.16, P = 0.4264), calibration in R Emax = 0.176, Eavg = 0.027, which all demonstrated that the model was of good accuracy. CONCLUSION: The nomogram predicting postoperative complications in patients with total hip replacement constructed based on age, type 2 diabetes, renal failure and ALB is of good discrimination and accuracy, which was of clinical significance.

7.
Int Immunopharmacol ; 82: 106354, 2020 Mar 03.
Article in English | MEDLINE | ID: mdl-32143008

ABSTRACT

The 5-hydroxytryptamine (5-HT) receptor is significant for the regulation of mood and memory. However, the role of 5-HT1AR in ß-Amyloid protein (Aß)-induced cognitive decline, neuroinflammation and the possible mechanism remains elusive. Thus, we aimed to evaluate the effects of 5-HT1AR on Aß-induced learning and memory decline and neuroinflammation in mice. Novel object recognition and Morris water maze tests were performed to observe learning and memory behavior in mice. Protein levels of Iba1, GFAP, MAP2, TNF-α, Tß4, C-fos, IKK-ß, IKB-α, NF-κBp65, phospho-NF-κBp65 in the hippocampus were examined by immunostaining or western blotting. Aß1-42-treatment inducing learning and memory decline was shown in novel object recognition and Morris water maze tests; neuroinflammation shown in immunostaining. Our study found out that 5-HT1AR inhibitor WAY100635 showed significant improvement in Aß-induced learning and memory decline. Moreover, WAY100635 decreases levels of Iba1, GFAP, and TNF-α in the hippocampus, which were related to neuroinflammation. While treatment with 5-HT1AR agonist 8-OH-DPAT or ERK inhibitor U0126 exerted no effects or even aggravated Aß-induced learning and memory decline. In addition, WAY100635 could downregulate phospho-NF-κB in the hippocampus of Aß1-42-injected mice. These results provide new insight into the mechanism, for 5-HT1AR in Aß-induced cognitive impairments through crosstalk with the NF-κB signaling pathway. Our data indicated that WAY100635 was involved in the protective effects against neuroinflammation and improvement of learning and memory in Alzheimer's disease.

8.
Chin Med J (Engl) ; 133(3): 262-268, 2020 Feb 05.
Article in English | MEDLINE | ID: mdl-31809317

ABSTRACT

BACKGROUND: Fecal incontinence (FI) has been shown to be a common symptom in Western countries; however, there is few researches focusing on its epidemic condition in Chinese women. We conducted this national population-based epidemiology study to estimate the prevalence and risk factors of FI among adult Chinese women living in urban regions. METHODS: This is a subgroup analysis of a national population-based epidemiology study of FI. Total 28,196 adult women from urban regions of six provinces and municipalities participated in this research from 2014 to 2015. They finished the questionnaire under the direction of trained interviewers. FI was defined as accidental leakage of flatus and/or liquid or solid stool at least once in the past. The FI prevalence trend and risk factors were identified by the Cochran-Armitage test, Chi-square test, and multivariable logistic regression. RESULTS: The prevalence of FI in adult females in urban China was 0.43% (95% confidence interval: 0.35%-0.51%). Among women with FI, 42.96%, 82.96%, and 42.22% reported having leakage of solid, liquid stool, and gas, respectively. The overall FI prevalence and the incidence rate of solid stool/liquid stool/gas leakage increased with age. The mean Wexner score was 4.0% and 12.0% FI patients reported Wexner score ≥9. Body mass index ≥24 kg/m, pelvic organ prolapses, chronic constipation, chronic cough, alcohol consumption, physical diseases including chronic bronchitis and cancer, gynecological diseases like gynecological inflammation are risk factors for FI. Vaginal delivery was the risk factor for FI in females with labor history. CONCLUSIONS: FI was not a common symptom in adult Chinese women living in urban areas and there were some potential modifiable risk factors. TRIAL REGISTRATION: Chinses Clinical Trial Registry: ChiCTR-OCS-14004675; http://www.chictr.org.cn/showproj.aspx?proj=4898.


Subject(s)
Fecal Incontinence/epidemiology , Adult , Aged , Aged, 80 and over , China/epidemiology , Fecal Incontinence/etiology , Female , Humans , Middle Aged , Prevalence , Risk Factors
9.
Org Lett ; 20(21): 6868-6871, 2018 11 02.
Article in English | MEDLINE | ID: mdl-30359038

ABSTRACT

New types of [2.2]paracyclophane derivatives, g-BNMe2-Cp and m-BNMe2-Cp, in which electron-donating NMe2 and the electron-accepting BMes2 are introduced at the pseudo -gem and pseudo -meta positions, were designed and synthesized. The efficient through-space charge transfer enables the intense fluorescence with thermally activated delayed fluorescence characteristics. The quantum yields are up to 0.72 and 0.39 in cyclohexane. In addition, no significant fluorescence quenching was observed in the solid state with fluorescence quantum yields of powder up to 0.53 and 0.33. Moreover, the enantiomerically pure forms of g-BNMe2-Cp exhibit strong CPL signals with glum up to 4.24 × 10-3.

10.
Chin Med J (Engl) ; 129(12): 1455-8, 2016 Jun 20.
Article in English | MEDLINE | ID: mdl-27270541

ABSTRACT

BACKGROUND: Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear. This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest. METHODS: Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion (control group) and from 45 patients who displayed early embryonic developmental arrest (trial group). RESULTS: Intrauterine bacterial infection was discovered in both groups. The infection rate was 24.44% (11/45) in the early embryonic developmental arrest group and 9.09% (3/33) in the artificial abortion group. Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% (6/45), and none was detected in the artificial abortion group. M. luteus infection was significantly different between the groups (P < 0.05 as shown by Fisher's exact test). In addition, no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest. CONCLUSIONS: M. luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.


Subject(s)
Abortion, Spontaneous/etiology , Abortion, Spontaneous/microbiology , Bacterial Infections/complications , Abortion, Induced/statistics & numerical data , Female , Humans , Micrococcus luteus/pathogenicity , Pregnancy , Uterus/microbiology
11.
Ying Yong Sheng Tai Xue Bao ; 22(11): 3021-5, 2011 Nov.
Article in Chinese | MEDLINE | ID: mdl-22303682

ABSTRACT

An investigation was conducted in Xing' an County of Guangxi Province in 2010 to study the occurrence and damage characteristics of two unique migratory pest insects, rice leaffolder (Cnaphalocrocis medinalis) and white-backed planthopper (Sogatella furcifera), in a transgenic Bt rice (cv. HH1 with dual Cry1Ab+Cry1Ac genes) field, taking the corresponding non-transgenic parent (cv. MH63) field as the control. No significant differences were observed in the abundance of C. medinalis eggs and larvae in the two fields, but the percentage of fold-leaf plants and the fold-leaf rate per plant were significantly lower in transgenic Bt rice field than in the control, suggesting that transgenic Bt rice had higher resistance against the target pest insect C. medinalis. As for S. furcifera, its occurrence dynamics of nymphs, adults (including macro- and brachypterous forms), and whole population had no significant differences between the two fields, but the abundance of the nymphs and brachypterous adults at the peak stage of S. furcifera occurrence was obviously higher in transgenic Bt rice field than in the control, while the macropterous abundance was in adverse. The sex ratio of female of the macropterous adults at the late growth stage of rice was generally lower in transgenic Bt rice field than in the control. These results suggested that under the background of large area commercial production of transgenic Bt rice, the occurrence and harm of the non-target pest insect S. furcifera could become more complicated.


Subject(s)
Bacterial Proteins/genetics , Endotoxins/genetics , Hemolysin Proteins/genetics , Lepidoptera/physiology , Oryza/genetics , Pest Control, Biological/methods , Animals , Bacillus thuringiensis Toxins , Plants, Genetically Modified/genetics
12.
Huan Jing Ke Xue ; 29(6): 1495-501, 2008 Jun.
Article in Chinese | MEDLINE | ID: mdl-18763490

ABSTRACT

The purpose of this paper is the application of storm water management model (SWMM) in simulating runoff hydrology and water quality. The study chose a roof as the typical impervious urban land surface, and monitored several rainfall-runoff events for parameter identification. We identified and validated hydrological and water quality parameters, using Monte Carlo sampling method and HSY algorithm, which are based on uncertainty analysis. Results show that impervious urban land surface runoff model includes 6 critical parameters, which are depression storage (S-imperv), Manning's n (N-imperv), maximum buildup possible (max buildup), buildup rate constant (rate constant), washoff coefficient (coefficient), and washoff exponent (exponent). Identification of S-imperv and N-imperv could use least square error as objectives, while others could use errors of event pollution load and peak concentration of pollutant as objectives. The identification results of the 6 parameters are N-imperv 0.012-0.025,S-imperv 0-0.7, max buildup 15-30,rate constant 0.2-0.8,coefficient 0.01-0.05, and exponent 1.0-1.2. Regional sensitivities of these parameters in non-ascending order are coefficient, S-imperv, N-imperv, max buildup, exponent, and rate constant. Identified parameters are able to be validated by SWMM model. However, current model structures still have some difficulties in simulating runoff pollutant concentration curves caused by some special rain patterns.


Subject(s)
Models, Theoretical , Rain , Water Movements , Water Pollutants/analysis , Algorithms , China , Cities
13.
Huan Jing Ke Xue ; 29(3): 607-12, 2008 Mar.
Article in Chinese | MEDLINE | ID: mdl-18649515

ABSTRACT

The purpose of this study is identification and characterization of hydrological process of urban runoff, as well as concentration variation of pollutants in it. Samples were collected in 4 rainfall events in Beijing from Jun. 2006 to Aug. 2006. Hydrology and pollution of the rainfall-runoff process were analyzed on roof and road. Study results show that the shapes of hydrological curves of runoff, despite for a 5 - 20 min delay and a milder tendency, are similar to rainfall curves. Runoff coefficients of roof are 0.80 - 0.98, while 0.87 - 0.97 of road. Event mean concentrations (EMC) of pollutants are influenced by build-up and wash-off features, which leads to a higher concentration in road runoff than in roof runoff. Major pollutants that excess the water quality standards are COD, TN, and TP. Evident correlations (> 0.1) are found between pollutants. Correlation with particles are higher for COD and SO4(2-) (> 0.5), while lower for nutrients (<0.5). First flush effects (FFE) are found and affected by several factors, such as pollutant variety, types of land covers, and rainfall intensity. FFE are found more intense in SS, more frequently in road runoff, and more difficult to form for COD and nutrients with low rainfall intensity. Therefore, control of first period of runoff would be an effective approach for runoff management in Beijing.


Subject(s)
Cities , Rain , Water Movements , Water Pollutants, Chemical/analysis , China , Environmental Monitoring , Models, Theoretical
14.
Yao Xue Xue Bao ; 38(7): 537-42, 2003 Jul.
Article in Chinese | MEDLINE | ID: mdl-14515802

ABSTRACT

AIM: To indicate the titration end-point of precipitation reaction by measuring the relative intensity of the scattered light in the titrate for use in pharmaceutical analysis. METHODS: A visible light-emitting diode (LED) was used as a light source and a photodiode was used as the optical detector. Light on the detector creates an electric current through the diode. With the addition of the titrant, the titrate became turbid and the intensity of the scattered light in the solution increased gradually. If the precipitation reaction proceeded the completion and the solubility of the precipitate was small enough, the intensity of the scattered light will reach maximum at the stoichiometric point; thus, the titration end-point can be indicated. The accuracy of nephelometric titrimetry was discussed theoretically and the titration of NaCl with AgNO3 was used as a model. To demonstrate the applicability of the new titrimetry in pharmaceutical analysis, phenytoin sodium and procaine hydrochloride were titrated with AgNO3 and NaOH solutions, respectively. RESULTS: With our new titrator and nephelometric sensor, the accuracy and precision of our new titrimetry can be better than 0.2% under suitable conditions. CONCLUSION: This new titrimetry can be used for pharmaceutical analysis.


Subject(s)
Titrimetry/methods , Phenytoin/analysis , Procaine/analysis , Titrimetry/instrumentation
15.
Yao Xue Xue Bao ; 37(2): 148-52, 2002 Feb.
Article in Chinese | MEDLINE | ID: mdl-12579964

ABSTRACT

AIM: To study the effect of both light and heat on the stability of furacilin aqueous solution and the probability of substituting for isothermal accelerated tests by nonisothermal accelerated tests upon exposure to light at high temperatures. METHODS: The isothermal and nonisothermal accelerated tests were employed. The accelerated tests were proceeded in the dark and exposed to light at high temperature. Tungsten, ultraviolet and fluorescent lamps were employed in exposure tests. RESULTS: The degradation of furacilin aqueous solution in isothermal heating experiments or the exposure experiments to light at high temperatures obeys zero-order kinetics. The total degradation rate constant k caused by both light and heat can be divided into two parts: k = kdark + klight, where kdark and klight are the degradation rate constant caused by heat and light, respectively. The klight can be expressed as klight = Alight.exp(-Ea,light/RT).E, where E is the illuminance of light; Alight and Ea,light are both experimental constants. The parameters obtained in nonisothermal accelerated tests were comparable to those obtained in classic isothermal accelerated tests. CONCLUSION: Nonisothermal accelerated tests may substitute for isothermal accelerated tests during the study of the effects of both light and heat on the stability of drugs, in order to save time, labor and drugs.


Subject(s)
Hot Temperature , Light , Nitrofurazone/chemistry , Anti-Infective Agents, Local/chemistry , Drug Stability , Mathematics , Solutions
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