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1.
Phys Chem Chem Phys ; 26(8): 7083-7089, 2024 Feb 22.
Article in English | MEDLINE | ID: mdl-38345644

ABSTRACT

The application of in situ Raman spectroscopy under multiple fields is widely recognized as an effective approach for investigating the physical mechanism of phase transitions in ferroelectrics, because it can directly provide the detailed information about the vibration evolution of various phonon modes within lattices, such as bond stretching and rotation. Based on this technique, our work aims to thoroughly probe the dynamics of phase transitions in traditional ferroelectric potassium sodium niobate [(K,Na)NbO3, KNN] under external fields, by analyzing the in situ dependence of wavenumber and intensity of phonon modes under the varying temperature and electric fields. The results indicate that different vibration modes respectively relating to the A-site ions and NbO6 octahedra in KNN exhibit distinct and abrupt distortion behavior during the orthorhombic-tetragonal and tetragonal-cubic transitions. Moreover, a certain degree of distortion can still be observed in the cubic phase above the Curie temperature. With an applied electric field, KNN presents quite different electrostriction in orthorhombic and tetragonal phases. Particularly, more than one kind of phonon mode undergoes non-linear variations under the varying electric fields, accompanied by the mutations at some fixed fields. These findings will be conducive to further understanding the phase transition mechanism in KNN from the perspective of phonon evolution. Simultaneously, it will also give crucial guidance for the design and development of KNN-based ferroelectrics as well as functional devices.

2.
Beijing Da Xue Xue Bao Yi Xue Ban ; 54(3): 541-547, 2022 Jun 18.
Article in Chinese | MEDLINE | ID: mdl-35701133

ABSTRACT

OBJECTIVE: To investigate the clinical characteristics and risk factor analysis of necrotizing pneumonia in children. METHODS: A retrospective study was used to analyze the case data of 218 children with severe pneumonia hospitalized in the Department of Respiratory Medicine, Children's Hospital of Capital Institute of Pediatrics from January 2016 to January 2020, and they were divided into 96 cases in the necrotizing pneumonia group (NP group) and 122 cases in the non-necrotizing pneumonia group (NNP group) according to whether necrosis of the lung occurred. The differences in clinical characteristics (malnutrition, fever duration, hospitalization time, imaging performance, treatment and regression follow-up), laboratory tests [leukocytes, neutrophil ratio, platelet (PLT), C-reactive protein (CRP), procalcitonin (PCT), D-dimer, and lactate dehydrogenase (LDH)] and bronchoscopic performance between the two groups were compared, and Logistic regression analysis of clinical risk factors associated with necrotizing pneumonia was performed to further determine the maximum diagnostic value of each index by subject operating characteristic curve (ROC). The critical value of each index was further determined by the ROC. RESULTS: The differences in age, gender, pathogenic classification, and bronchoscopic presentation between the two groups of children were not statistically significant (P>0.05); whereas the imaging uptake time of the children in the NP group was higher than that in the NNP group (P < 0.05). The differences in malnutrition, fever duration, length of stay, white blood cell count, neutrophil ratio, CRP, PCT, and D-dimer were statistically significant between the two groups (P < 0.05). The imaging uptake time was lower in children under 6 years of age than in those over 6 years of age, and the imaging uptake time for bronchoalveolar lavage within 10 d of disease duration was lower than that for those over 10 d; the imaging uptake time was significantly longer in the mixed infection group than that in the single pathogen infection group. Logistic regression analysis of the two groups revealed that the duration of fever, hospital stay, CRP, PCT, and D-dimer were risk factors for secondary pulmonary necrosis (P < 0.001, P < 0.001, P < 0.001, P=0.013, P=0.001, respectively). The ROC curves for fever duration, CRP, PCT, and D-dimer were plotted and found to have diagnostic value for predicting the occurrence of pulmonary necrosis when fever duration >11.5 d, CRP >48.35 mg/L, and D-dimer > 4.25 mg/L [area under ROC curve (AUC)=0.909, 0.836, and 0.747, all P < 0.001]. CONCLUSION: Children with necrotizing pneumonia have a longer heat course and hospital stay, and the imaging uptake time of mixed pathogenic infections is significantly longer than that of single pathogenic infections. Children with necrotizing pneumonia under 6 years of age have more advantageous efficacy of electronic bronchoscopic alveolar lavage within 10 d of disease duration compared with children in the group over 6 years of age and children in the group with disease duration >10 d. Inflammatory indexes CRP, PCT, and D-dimer are significantly higher. The heat course, CRP, PCT, and D-dimer are risk factors for secondary lung necrosis in severe pneumonia. Heat course >11.5 d, CRP >48.35 mg/L, and D-dimer >4.25 mg/L have high predictive value for the diagnosis of necrotizing pneumonia.


Subject(s)
Malnutrition , Pneumonia, Necrotizing , Pneumonia , C-Reactive Protein/analysis , Child , Child, Preschool , Humans , Necrosis , Pneumonia/diagnosis , Prognosis , ROC Curve , Retrospective Studies , Risk Factors
3.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 32(15): 1203-1206, 2018 Aug 05.
Article in Chinese | MEDLINE | ID: mdl-30282160

ABSTRACT

Chronic rhinosinusitis (CRS), a chronic inflammation of the nasal sinus mucosa, is based on a simplified classification of a single clinical phenotype (with or without nasal polyps) that does not adequately reflect the heterogeneity of the pathogenesis of chronic rhinosinusitis complexity. Currently, according to the lesion mucosa or polyps eosinophil infiltration,this type of chronic rhinosinusit is known as eosinophilic chronic rhinosinusitis (ECRS). The curative effect of ECRS is poor than non-eosinophilic rhinosinusitis. This article summarizing the diagnosis and treatment of eosinophilic rhinosinusitis status, is to provide help for clinical diagnosis and treatment.

4.
Article in Chinese | MEDLINE | ID: mdl-29921080

ABSTRACT

Objective:We explored the role of CT scan in the diagnosis of eosinophilic chronic rhinosinusitis (ECRS) in sinus osteitis for a better guidance of clinic and treatment. Method:A total of 127 patients with chronic rhinosinusitis who underwent primary surgery were collected(52 patients were ECRS). Seventy-five patients with NonECRS performed global osteitis scoring scale (GOSS) osteitis score on the patient's preoperative sinus CT. Mamn-Whitney U analysis was used to compare the GOSS osteitis scores between the two groups. A binary logistic regression analysis was performed on the statistically significant indicators to find predictive GOSS osteitis scores. Receiver operating characteristic curve (ROC curve) analysis was performed on meaningful indicators to analyze the relationship among the cutoff values the sensitivity and the specificity to find the best cutoff value. Result:The osteitis evaluation index GOSS osteitis total score,ethmoid osteitis scores(GOSS-E), ethmoid osteitis score compared with the maxillary osteitis score (GOSS-E/M), posterior group ethmoid sinus osteitis score compared with the former group ethmoid sinus osteitis score (GOSS-PE/AE), anterior ethmoid osteitis scores (GOSS-AE), posterior ethmoid osteitis scores (GOSS-PE), sphenoid osteitis scores (GOSS-S), ECRS significantly higher than NonECRS(P<0.05); binary logistic regression analysis and ROC curve analysis were performed. When the cut-off value of the ethmoid osteitis score was >4.5 (area under the curve was 0.690), the corresponding sensitivity and specificity were 62% and 71%, respectively. Conclusion:When the ethmoid sinus CT is used to obtain a ethmoid osteitis score of >4.5,the ECRS can be diagnosed clinically.


Subject(s)
Rhinitis/diagnostic imaging , Sinusitis/diagnostic imaging , Tomography, X-Ray Computed , Chronic Disease , Humans , Osteitis/diagnostic imaging , Paranasal Sinuses
5.
Article in Chinese | MEDLINE | ID: mdl-29871213

ABSTRACT

When it comes to the treatment of oropharyngeal cancer, the recurrence rate is high after radiotherapy, chemotherapy or open surgery. Transoral robotic surgery is a relatively new surgical therapy in oropharyngeal cancer, which can promote the development of minimally invasive surgery of oropharyngeal cancer. In this study, we reviewed flap reconstruction techniques of transoral robotic surgery, outcomes, contraindications,advantages and disadvantages.


Subject(s)
Oropharyngeal Neoplasms/surgery , Robotic Surgical Procedures/methods , Robotic Surgical Procedures/trends , Surgical Flaps
6.
Article in Chinese | MEDLINE | ID: mdl-29871267

ABSTRACT

Objective:To evaluate the impact of postoperative vocal different functional characteristics with laser treatment for early laryngeal cancer.Method:Computer searching the major medical-related databases: PubMed, Web of Science and Embase, searching and screening by two staff members at the same time to read the relevant literatures, extraction of data and research related to the purpose from the selected literature. Using Stata 14.0 software analysis the extracted data with Bayesian network Metaanalysis, get the laser surgery of early laryngeal cancer effects of different voice characteristics of vocal cord.Result:A total of nine articles was included finally according through the necessary conditions, statistical analysis results showed that early laryngeal laser surgery can significantly reduce GRABS and VHI assessment score.Conclusion:Laser treatment of early laryngeal cancer could reduce VHI and the GRABS assessment score postoperatively, improve overall postoperative vocal cord function and the quality of life of patients after surgery, but not in the early post-operative function and physiology in vocal function.


Subject(s)
Carcinoma, Squamous Cell/surgery , Laryngeal Neoplasms/surgery , Laser Therapy , Voice , Humans , Quality of Life , Treatment Outcome , Vocal Cords , Voice Quality
7.
Article in Chinese | MEDLINE | ID: mdl-29871304

ABSTRACT

Objective:To compare larynx preservation rate, local control rate, overall survival rate and disease-specific survival rate after laser surgery and radiotherapy of T1a glottic carcinoma. Method:PubMed, Web of Science, Embase, Cochrane Library,Chinese biomedical literature datebase,CNKI and Wanfang digital journals were searched from the built of the datebases to October 2016 by computer. Literature screening,date extraction and quality assessment were conducted independently by two co-authors,and the meta-analysis was made with Review Manager 5.3. Result:Twelve literatures were included finally, and statistical analysis results showed that radiotherapy was superior to laser surgery in the laynx preservation rate of T1a glottic carcinoma(OR=3.23,95%CI=1.21~8.60,P=0.02) , overall survival rate and specific disease survival rate were not significant different between laser surgery and radiotherapy. Conclusion:Radiotherapy is superior to laser surgery in the laynx preservation rate of T1a glottic carcinoma.


Subject(s)
Carcinoma, Squamous Cell/radiotherapy , Carcinoma, Squamous Cell/surgery , Laryngeal Neoplasms/radiotherapy , Laryngeal Neoplasms/surgery , Laser Therapy , Radiotherapy , Carcinoma, Squamous Cell/mortality , Humans , Laryngeal Neoplasms/mortality , Larynx , Neoplasm Staging , Retrospective Studies , Treatment Outcome
8.
Article in Chinese | MEDLINE | ID: mdl-29871334

ABSTRACT

Ossifying fibroma is a rare benign osteogenic neoplasm arising from undifferentiated cells of the periodontal ligament and with a potential to form fibrous tissue, cementum and bone, which is usually in molar area of the mandible, predominantly seen in young girls. And ossifying fibroma poses diagnostic and therapeutic difficulties due to their clinical, radiological and histological variabilities. We report a rare case of an 18 year old girl with cystic degeneration of ossifying fibroma in maxilla which is an uncommon site of occurrence.


Subject(s)
Endoscopy/methods , Adolescent , Female , Fibroma/pathology , Fibroma, Ossifying/diagnosis , Fibroma, Ossifying/surgery , Humans , Maxillary Sinus/pathology , Maxillary Sinus Neoplasms/diagnosis , Maxillary Sinus Neoplasms/surgery , Osteoma/pathology , Paranasal Sinus Neoplasms/pathology , Treatment Outcome
9.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 30(20): 1659-1663, 2016 Oct 20.
Article in Chinese | MEDLINE | ID: mdl-29871168

ABSTRACT

The treatment options and prognosis of recurrent head and neck squamous cell carcinoma are largely determined by site, extent of disease,and previous treatment. Salvage surgery represents the primary curative option when recurrent head and neck squamous cell carcinoma is resectable. The common factors that affect the prognosis of patients undergoing salvage surgery include surgical resection margin pathology, radiation therapy, advanced initial and recurrent tumor stage, and presence of concomitant neck disease. This paper reviewed the advancement of salvage surgery for recurrent head and neck squamous cell carcinoma.

10.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 30(21): 1744-1746, 2016 Nov 05.
Article in Chinese | MEDLINE | ID: mdl-29871191

ABSTRACT

Transoral robotic surgery(TORS) with the Da Vinci robot has been used for the removal of laryngeal cancer,which can improve functional and aesthetic outcomes without worsening survival. We reviews the composition of the robotic surgical system, unique advantages, potential applications and limitations of existing solutions and prospects in Surgery for laryngeal cancer.Major technical improvements are expected. Smaller, more ergonomic, new-generation robots adapted to the head and neck will probably be available in the near future.

11.
Int J Tuberc Lung Dis ; 17(2): 243-5, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23317961

ABSTRACT

Genotyping that differentiates between strains of Mycobacterium tuberculosis based on variations in the genome of the organism is a useful tool for molecular epidemiological studies of tuberculosis. In the present study, we identified a combination of five mycobacterial interspersed repetitive unit (MIRU) loci and three variable numbers of tandem repeats (VNTR) loci of M. tuberculosis that showed a discriminatory power comparable to that of the 15 to 24 loci-based typing proposed for international standardisation in analysing 210 paediatric isolates obtained from Chongqing, China.


Subject(s)
DNA, Bacterial/genetics , Mycobacterium tuberculosis/genetics , Sputum/microbiology , Tuberculosis/microbiology , Bacterial Typing Techniques , Child , Genotype , Humans , Minisatellite Repeats , Mycobacterium tuberculosis/isolation & purification , Polymerase Chain Reaction
12.
Zhongguo Yi Liao Qi Xie Za Zhi ; 25(4): 192-5, 2001 Jul.
Article in Chinese | MEDLINE | ID: mdl-12583214

ABSTRACT

A convenient and effective method of rigid registration and fusion between SPECT and MRI/CT which is based on external fiducial alignment system is designed. After thresholding the image, many image processing arithmetics such as erosion, dilation are used to ensure the corresponding points which will be used to registrate. Then these points are used to minimize the cost function. In this way, an optimal rigid transform is gotten to registrate the images accurately and fuse them well. Error in the registration and fusion is reduced furthest by well designing the N-shape bracket which is used as the external fiducial alignment system and also by limiting the relative displacement between the bracket and the patient. Experimentation shows that this method can realize the registration and fusion of SPECT and MRI/CT effectively.


Subject(s)
Algorithms , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging , Tomography, Emission-Computed, Single-Photon , Tomography, X-Ray Computed
13.
Zhongguo Yi Liao Qi Xie Za Zhi ; 24(3): 143-6, 2000 Mar.
Article in Chinese | MEDLINE | ID: mdl-12583120

ABSTRACT

A new kind of multifunctional radioactive nuclide diagnostic instrument is described here, which can make noninvasive measurements on the metabolic functions of five most important inner organs which are kidney, liver, heart and thyroid. The design of the hardware and software of the new instrument embodies many advanced advantages such as multifunctional integration, high accuracy and high reliability, computer controlled, automatic data-processing, easy to use and manage, and so on. Applications show that this is an advanced and efficient radioactive medical diagnostic instrument.


Subject(s)
Radionuclide Imaging/instrumentation , Software , Equipment Design , Radionuclide Imaging/methods , Software Design
14.
J Protein Chem ; 18(5): 603-7, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10524778

ABSTRACT

The inhibition of alkaline phosphatase from green crab (Scylla serrata) by L-cysteine has been studied. The results show that L-cysteine gives a mixed-type inhibition. The progress-of-substrate-reaction method previously described by Tsou [(1988), Adv. Enzymol. Related Areas Mol. Biol. 61, 391-436] was used to study the inactivation kinetics of the enzyme by L-cysteine. The microscopic rate constants were determined for reaction of the inhibitor with the free enzyme and the enzyme-substrate complex (ES) The results show that inactivation of the enzyme by L-cysteine is a slow, reversible reaction. Comparison of the inactivation rate constants of free enzyme and ES suggests that the presence of the substrate offers marked protection of this enzyme against inactivation by L-cysteine.


Subject(s)
Alkaline Phosphatase/antagonists & inhibitors , Brachyura/enzymology , Cysteine/pharmacology , Enzyme Inhibitors/pharmacology , Animals , Kinetics , Substrate Specificity
15.
Biochem Mol Biol Int ; 45(3): 465-73, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9679647

ABSTRACT

Green crab (Scylla Serrata) alkaline phosphatase (EC 3.1.3.1) is a metalloenzyme which catalyzed the nonspecific hydrolysis of phosphate monoesters. In the present paper, the effects of several N-thiophosphoryl amino acids on the activity of green crab alkaline phosphatase have been studied. The results show that these derivatives of amino acids can lead to reversible inactivation. The equilibrium constants for inhibitors binding with the enzyme and/or the enzyme-substrate complexes have been determined. The obtained results show that both N-thiophosphoryl-Cys and N-thiophosphoryl-Glu were non-competitive inhibitors, while other five N-thiophosphoryl amino acids were un-competitive inhibitors. For the un-competitive inhibitors, the inhibition strength follows the order N-thiophosphoryl-Ile > -Val > -Lys > -Ala > -Tyr. Compared with respective free amino acids, it can be seen that N-thiophosphorylation of the amino acids increased their inhibition strength except the N-thiophosphoryl-Cys.


Subject(s)
Alkaline Phosphatase/antagonists & inhibitors , Amino Acids/pharmacology , Brachyura/enzymology , Amino Acids/chemistry , Animals , Binding, Competitive , Enzyme Inhibitors/pharmacology
16.
J Biol Chem ; 267(2): 714-8, 1992 Jan 15.
Article in English | MEDLINE | ID: mdl-1346132

ABSTRACT

Leukocyte adhesion deficiency (LAD) is an autosomal recessive disease caused by mutations in the CD18 gene which codes for the beta 2 integrin subunit. We studied two patients, the first of which had a moderate LAD phenotype and expressed only 9% of CD11/CD18 on blood leukocytes. RNA from lymphoblasts was reverse-transcribed, and the cDNA was amplified, cloned, and sequenced. An ATG to AAG alteration in the initiation codon was detected in 39 of 45 (87%) cDNA clones. This mutation was detected in the father, but not in the mother. The maternal defect was shown to be a frameshift mutation with the deletion of a single T in the aspartic acid codon at position 690 (GAT), 11 amino acids N-terminal to the beginning of the transmembrane domain. This mutation predicts a polypeptide which would terminate without transmembrane or cytoplasmic domains. The frameshift mutation was also found in the second patient who had the severe phenotype of LAD (less than 1% of CD11/CD18), indicating that this allele does not encode a functional protein. The partial expression in the patient with a moderate phenotype must be derived from the initiation codon mutation and may be due to a low level of initiation of translation of the CD18 mRNA at the second codon (CUG).


Subject(s)
Antigens, CD/genetics , Frameshift Mutation , Phenotype , Receptors, Leukocyte-Adhesion/genetics , Base Sequence , CD11 Antigens , CD18 Antigens , Child , Codon , DNA/genetics , Fluorescent Antibody Technique , Humans , Male , Molecular Sequence Data , Pedigree , Polymerase Chain Reaction , Sequence Homology, Nucleic Acid
17.
Zhonghua Shen Jing Jing Shen Ke Za Zhi ; 23(6): 339-41, 383, 1990 Dec.
Article in Chinese | MEDLINE | ID: mdl-2098243

ABSTRACT

This study tested 131 patients with psychoses and contrasted the MMPI with the SCL-90. It was found that the nine groups of elemental symptoms in the SCL-90 was highly related with the corresponding symptoms in the MMPI. However, the relatively of groups in the two scales is different in the three diseases of schizophrenia, depression and neurosis. It was expressed that the three mental diseases possessed different psychopathologic characters. The result corresponded to clinical experience and also showed that SCL-90 was a self-rating scale with higher validity and spread of the scale was feasible.


Subject(s)
Depression/diagnosis , MMPI , Neurotic Disorders/diagnosis , Schizophrenia/diagnosis , Adolescent , Adult , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales/methods
18.
Biochem Cell Biol ; 68(6): 944-8, 1990 Jun.
Article in English | MEDLINE | ID: mdl-2168719

ABSTRACT

In Physarum flavicomum Berk., haploid myxamoebae convert to dormant microcysts under conditions of nutrient imbalance. Exogenous adenine increases the intracellular content of S-adenosylmethionine (SAM) and inhibits this process. However, treatments that reduce the intracellular SAM levels relieve the inhibition of encystment induced by adenine. SAM plays a major metabolic role in cellular transmethylation reactions. In this study, we compared the DNA methylation patterns of growing cells, encysting cells, adenine-inhibited cells, and cysts using three different approaches: incubation of the cells with [14C]methylmethionine and detection of the labeled methyl group in purified DNA samples; analyses of DNA base composition by high performance liquid chromatography; and restriction endonuclease analyses of DNA. We found that DNA from the adenine-treated cells was labelled 1.3 times more with [14C]methylmethionine than was the DNA of untreated encysting cells. The DNA G + C content of this species was about 41%. The DNA of growing cells had the highest 5-methylcytosine (5MC) content, while DNA from the cysts had the lowest (about 27% that of growing cells). Adenine-inhibited cells had about 1.2 times more DNA-5MC than did encysting cells. Using the restriction enzymes SmaI, PvuI, and XhoI (which are inhibited by C residue methylation), we found that cyst DNA had more cutting sites than did amoebal DNA. By using the restriction enzyme DpnI which cuts DNA at GmATC sites, we found that cyst DNA, but not growing cell DNA, contained N6-methyladenine.


Subject(s)
DNA, Fungal/metabolism , Physarum/growth & development , Adenine/metabolism , Carbon Radioisotopes , Chromatography, High Pressure Liquid , Cytosine/metabolism , DNA Restriction Enzymes , Methionine/analogs & derivatives , Methionine/metabolism , Methylation
19.
Can J Microbiol ; 36(5): 366-8, 1990 May.
Article in English | MEDLINE | ID: mdl-2390746

ABSTRACT

In Physarum flavicomum Berk., growing amoebae convert to dormant cysts under conditions of nutrient imbalance. Exogenous adenine inhibits the process and the cells produce an elevated intracellular concentration of S-adenosylmethionine. Evidence indicates that the increased level of S-adenosylmethionine is responsible for the disruption of the normal developmental process. One of the biological functions of S-adenosylmethionine is in polyamine synthesis and it is known that a well-controlled intracellular concentration of polyamines is essential for normal cell growth and differentiation. In this study, high-performance liquid chromatography was used to determine the intracellular polyamine patterns in growing cells, adenine-treated and normal encysting cells, and dormant cysts. Putrescine and spermidine were the most abundant polyamines found in the cells; growing cells had the highest level, adenine-treated cells had a 1.5 to 2.0 times higher level than normal encysting cells, while cysts had the lowest (only 3 and 12% of that of growing cells). Cadaverine and N1-acetylspermidine were found in all the cells and their levels decreased during encystment. Acetylputrescine was found in growing cells only and acetylspermine was found in all cells except cysts. Acetylcadaverine, N8-acetylspermidine, 1,3-diaminopropane, and spermine were not detected in any of the cells.


Subject(s)
Physarum/metabolism , Polyamines/metabolism , Adenine/pharmacology , Physarum/drug effects , Physarum/growth & development , Putrescine/metabolism , S-Adenosylmethionine/metabolism , Spermidine/metabolism
20.
Mol Cell Biochem ; 90(2): 145-53, 1989 Oct 31.
Article in English | MEDLINE | ID: mdl-2586495

ABSTRACT

We have used High Performance Liquid Chromatography to determine metabolite characteristics of three recent isolates of Acanthamoeba which exhibit cultural characteristics consistent with those of established potential pathogens. Growing amoebae and dormant cysts of these isolates were explored in regard to their qualitative and quantitative intracellular levels of polyamine and S-adenosylmethionine metabolites. The polyamine found in the greatest concentration in the growing cells was 1,3-diaminopropane (DAP), followed by spermidine (SPD). A low level of putrescine was also found in the growing cells. These polyamines significantly decreased in concentration as the amoebae differentiated to cysts. N8-acetylspermidine and acetylspermine were found in both developmental stages while acetylcadaverine was found only in growing amoebae and N1-acetylspermidine only in cysts. Acetylputrescine was present in both stages of two isolates but only in the growing amoebae of the third isolate. Spermine was not detected in any of the isolates. S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) were present in growing amoebae but SAM was undetectable or barely detectable in cysts. SAH also decreased in concentration during encystation of two of the isolates to a level comparable to that of the other isolate. The developmental transition from growing amoebae to dormant cysts is characterized metabolically by a threshold adjustment in concentration of SAM, SAH and of the polyamines (esp., DAP and SPD).


Subject(s)
Acanthamoeba/metabolism , Polyamines/metabolism , S-Adenosylmethionine/metabolism , Acanthamoeba/growth & development , Animals , Chromatography, High Pressure Liquid , DNA/isolation & purification , Dansyl Compounds/pharmacokinetics
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