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1.
Zhonghua Wai Ke Za Zhi ; 61(11): 989-994, 2023 Sep 27.
Article in Chinese | MEDLINE | ID: mdl-37767665

ABSTRACT

Objective: To investigate the clinical value of the novel approach,radical resection of the retroperitoneal lipo-lymphatic layer (RRRLLL),in the surgical treatment of resectable pancreatic head cancer. Methods: Between June 2020 and June 2022,a total of 221 patients with pancreatic head cancer underwent surgical treatment using the RRRLLL approach(RRRLLL group),while 107 patients received traditional surgical treatment(traditional group) in five high-volume pancreatic centers in China. Data from surgical technique and clinical perioperative outcomes,including lymph node harvested,surgical time,and complications,were analyzed. The RRRLLL group consisted of 144 males and 77 females with an age of (67.5±9.0) years(range:41.3 to 81.1 years). The traditional group included 71 males and 36 females,with an age of (66.3±8.1) years(range:45.1 to 79.2 years). Statistical analysis was performed using the K-S test,Z test,or χ2 test. Results: Pancreaticoduodenectomy was performed successfully in all patients,achieving R0 resection. RRRLLL group surgery required mobilization of retroperitoneal adipose and lymphatic tissues starting from the right edge of the inferior vena cava and extending to the left side,up to the superior mesenteric artery,down to the inferior mesenteric artery,and left to the left side of the aorta,including the perineural and lymphatic tissues around the superior mesenteric artery and the sheath of the mesenteric artery. However,the traditional group did not include the areas mentioned above in the scope of clearance. There were no statistically significant differences between the RRRLLL group and the traditional group in terms of age,sex,tumor size,T stage,and vascular invasion (all P>0.05). However,the number of lymph nodes harvested in the RRRLLL group was significantly higher at 28.7±9.0 (range: 18 to 39) compared to 18.2±8.0 (range: 12 to 21) in the traditional group (Z=-10.691,P<0.05). There were no statistically significant differences in the number of positive lymph nodes,N staging,and postoperative complications between the two groups. Conclusion: The RRRLLL approach improved lymph node dissection compared to the traditional approach,potentially leading to reduced recurrence rates.

2.
Zhonghua Yu Fang Yi Xue Za Zhi ; 56(10): 1423-1428, 2022 Oct 06.
Article in Chinese | MEDLINE | ID: mdl-36274608

ABSTRACT

Objective: To explore the impact of environmental temperature exposure on eczema visits. Methods: Eczema clinic data from January 1, 2016 to December 31, 2019 were collected from the Huizhou Dermatology Hospital, and data on meteorological factors (average daily temperature and relative humidity) for the same period were derived from 86 meteorological stations of the Guangdong Provincial Climate Center. A distributed lag nonlinear model (DLNM) was used to assess the lagged effect of environmental temperature exposure on eczema, and a natural smooth spline function was used to control the nonlinear confounding of humidity. Results: There were 254 053 eczema outpatient visits at the Huizhou Dermatology Hospital within four years, with an average of 173.89 visits per day. The relationship between daily average temperature and the number of visits was non-linear (U shape). The risk of eczema increased by 2.20% (1.19%-3.21%) for every 1 ℃ decrease for the low temperature, and increased by 2.35% (1.24%-3.5%) for every 1 ℃ increase for the high temperature. The effect of high temperature was greater than that of low temperature. In all cases, 1.60% (0.44%-2.68%) of eczema outpatient visits were attributed to low temperature and the attributable number was 4 065 (1 128-6 798), while 6.33% (1.40%-10.87%) of eczema outpatient visits were due to high temperature and the attributable number was 16 082 (3 557-27 616). Conclusion: Both high temperature and low temperature are associated with increased risk of eczema.


Subject(s)
Air Pollutants , Air Pollution , Eczema , Humans , Air Pollution/adverse effects , Temperature , Outpatients , Cities , Eczema/epidemiology , China/epidemiology , Air Pollutants/analysis
3.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 57(9): 907-913, 2022 Sep 09.
Article in Chinese | MEDLINE | ID: mdl-36097936

ABSTRACT

Objective: To compare the treatment effect of distraction osteogenesis (DO) and maxillomandibular advancement (MMA) for severe obstructive sleep apnea hypopnea syndrome (OSAHS) patients and to guide clinical decisions about treatment of OSAHS. Methods: Thirty-seven OSAHS patients which accepted maxillomandibular advancement (MMA) or distraction osteogenesis (DO) in Stomatological Hospital of the Department of Maxillofacial Trauma and Orthognathic Surgery, School of Stomatology, The Forth Military Medical University from June 2017 to June 2019 were collected. Their preoperative and postoperative data of cephalometry, polysomnography (PSG), Pittsburgh sleep quality index (PSQI) and Epworth sleepiness scale (ESS) scores were collected and analyzed. With propensity score matching method, the treatment effect of MMA and DO was analyzed and compared. Results: According to the statistics of MMA group, only AHI was correlated with operative successful rate and cure rate. With the increase of AHI, the treatment effect of MMA on OSAHS patients gradually decreased. The cut-off point of AHI as a predictor of MMA treatment failure was 78.2 n/h. All the matched cases were severe OSAHS patients. Statistical analysis showed that the mandibular elongation of DO patients[(24.00±4.39) mm] was significantly more than that of MMA group [(11.20±1.37) mm] (t=-6.11, P<0.001), the improvement of PSG index [including lowest oxygen saturation (LSpO2), longest apnea (LA) and longest hypopnea (LH)] in DO group [LSpO2=(93.40±1.82)%; LA=(18.28±8.32) s; LH=(61.84±32.94) s] was significantly higher than that in the MMA group [LSpO2=(86.00±4.06)%, LA=(64.08±21.78) s, LH=(172.40±30.70) s](t=-3.72, P=0.005; t=4.39, P=0.003; t=5.49, P=0.004). The PSQI and the ESS scores of DO group (PSQI=4.20±0.83; ESS=3.40±1.52) were also significantly better than that of MMA group (PSQI=8.80±2.39, ESS=9.40±2.88)(t=4.07, P=0.001; t=4.12, P=0.002). Conclusions: For severe OSAHS patients, the objective and subjective indicators of DO treatment group showed a better therapeutic effect than that of MMA.


Subject(s)
Mandibular Advancement , Osteogenesis, Distraction , Sleep Apnea, Obstructive , Humans , Retrospective Studies , Sleep Apnea, Obstructive/surgery , Treatment Outcome
5.
Zhonghua Wai Ke Za Zhi ; 58(10): 782-786, 2020 Oct 01.
Article in Chinese | MEDLINE | ID: mdl-32993266

ABSTRACT

Objective: To examine the surgical approach, practical cognition as well as clinical effect of the orthotopic resection for laparoscopic pancreatoduodenectomy(OLPD). Methods: From March 2019 to December 2019, 32 cases were treated with laparoscopic pancreatoduodenectomy (LPD) in a novel approach without mobilization of pancreatoduodenum in Pancreas Center of the Second Affiliated Hospital of Guangzhou University of Chinese Medicine.There were 16 male patients and 16 female patients.The mean age was (64.8±9.5) years old.Body mass index was 14.9 to 31.0 kg/m(2).All patients were diagnosed as ampullary or pancreatic head tumors and were not unresectable cases.In the surgical strategy, Kocher's dissociation, turning and pulling of the pancreaticoduodenal region, was not performed first.Anatomy in situ, separation of vessels which enter and exit from pancreas, separation of lymphatics and isolation of tumors were carried out in priority through the combined middle and left posterior approaches.Finally, the pancreatic head and duodenum region was mobilized and the entire resection of pancreas in situ was carried out.Digestive tract reconstruction was performed through Child method. Results: Postoperative pathology showed that 27 cases were pancreatic or ampullary malignant tumors and five cases were benign tumors among 32 patients.The operative time was (357.3±64.3) minutes.The diameter of pancreatic ducts was (3.0±1.0) mm. The pancreas of 20 cases (62.5%) were soft. Five patients suffered from pancreatic fistula (Grade B) and one patient suffered from intra-abdominal hemorrhage postoperatively.No other complications like pancreatic fistula (Grade C) or biliary fistula delayed gastric emptying or mortality were encountered.The postoperative hospital day was (13.7±3.6) days. Conclusions: Combining the multi-angle of the laparoscopic approaches and excising the pancreaticoduodenal specimen in situ, OLPD is a kind of surgical method which can realize the concept of no touch tumor surgery.Patients who undergo the OLPD can receive better treatments and results.


Subject(s)
Laparoscopy , Pancreatic Neoplasms , Pancreaticoduodenectomy , Aged , Female , Humans , Male , Middle Aged , Pancreas/surgery , Pancreatic Neoplasms/surgery , Pancreaticoduodenectomy/methods
6.
J Thromb Haemost ; 16(1): 74-82, 2018 01.
Article in English | MEDLINE | ID: mdl-29108091

ABSTRACT

Essentials Blood loss and immune reaction are closely related to morbidity and recovery after surgery. We studied the effect of epinephrine plus tranexamic acid on blood loss and immune reaction. Epinephrine plus tranexamic acid reduced postoperative total blood loss and immune reaction. Epinephrine plus tranexamic acid did not increase the incidence of complications. SUMMARY: Background Hemostasis, thrombosis and surgical stress-induced immune reactions are important for perioperative morbidity and recovery after major surgical operations. Objectives To evaluate the effects of combined administration of low-dose epinephrine (LDEPI) and tranexamic acid (TXA) on perioperative blood loss, thromboembolic complications and inflammatory responses in patients undergoing total hip arthroplasty (THA). Patients/Methods Patients scheduled for THA (n = 195) were randomized into three interventions: intravenous LDEPI plus TXA (group IV); topical diluted epinephrine plus TXA (group TP); and TXA alone as control (group CT). The primary outcome was perioperative blood loss on postoperative day (POD) 1. Secondary outcomes included perioperative blood loss on POD 3, intraoperative blood loss, volume of drainage, transfusion values, coagulation and fibrinolysis parameters, inflammatory cytokine levels, cases of thrombosis, intravenous fluid on the operation day, and length of hospital stay. Results The mean calculated amounts of total blood loss in groups IV, TP and CT were 631.2 mL, 760.5 mL, and 825.6 mL, respectively, on POD 1; treatment effects (differences) were 194.4 mL (95% confidence interval [CI] 146.7-242.0) and 65.0 mL (95% CI 17.4-112.7). Groups IV and TP had lower levels of proinflammatory cytokines (tumor necrosis factor-α and interleukin [IL]-1ß) and higher levels of the anti-inflammatory cytokine IL-10, and showed faster development of coagulation and fibrinolysis (without change in peak levels), than group CT early postoperation. No differences were observed in transfusion, thromboembolic and other outcomes among the groups. Conclusion The combined administration of LDEPI and TXA was more effective in reducing perioperative blood loss and alleviating the inflammatory response than TXA alone, without increasing the incidence of thromboembolic and other complications.


Subject(s)
Adrenergic Agonists/administration & dosage , Anti-Inflammatory Agents/administration & dosage , Antifibrinolytic Agents/administration & dosage , Arthroplasty, Replacement, Hip/adverse effects , Blood Loss, Surgical/prevention & control , Epinephrine/administration & dosage , Hemostasis/drug effects , Inflammation/prevention & control , Postoperative Hemorrhage/prevention & control , Tranexamic Acid/administration & dosage , Adrenergic Agonists/adverse effects , Adult , Aged , Anti-Inflammatory Agents/adverse effects , Antifibrinolytic Agents/adverse effects , China , Drug Administration Schedule , Drug Therapy, Combination , Epinephrine/adverse effects , Female , Humans , Inflammation/etiology , Inflammation/immunology , Male , Middle Aged , Postoperative Hemorrhage/blood , Postoperative Hemorrhage/etiology , Time Factors , Tranexamic Acid/adverse effects , Treatment Outcome , Young Adult
7.
Skin Res Technol ; 22(1): 98-103, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26096793

ABSTRACT

BACKGROUND/PURPOSE: The monitoring of autofluorescence in skin tissue samples can have diagnostic and therapy significance. In this study, we are the first to describe autofluorescence of eccrine sweat glands, which is important and helpful for the diagnosis and therapy of diseases that involve the eccrine sweat glands. METHODS: Eccrine sweat gland autofluorescence in haematoxylin-eosin (HE) stained skin tissue sections was observed under a fluorescence microscope, which was compared to the immunofluorescence of keratin 19 and 15 in the skin tissue sections. The single eccrine sweat glands from five volunteers including three males and two females were isolated and also observed under a fluorescence microscope. The autofluorescence intensity of the single eccrine sweat gland was measured using a laser confocal scanning microscope system. RESULTS: Eccrine sweat gland autofluorescence in HE stained skin tissue sections appears green under GFP fliter system (470/40 nm) and red under N2.1 fliter system (515-560 nm). Furthermore, the single eccrine sweat gland showed various autofluorescence colours, including green under wide blue and red under wide green. The autofluorescence intensity of the single eccrine sweat gland was measured. The spectrum excited at 488 nm exhibited two peaks located at approximately 530 nm (11.54 ± 4.66) and 590 nm (10.38 ± 4.33). The results suggest flavin and lipopigment as the endogenous fluorophores. CONCLUSION: The autofluorescence of the HE stained eccrine sweat gland sections is simple and helpful for easily determining the structure of eccrine sweat glands. The autofluorescence of the single eccrine sweat gland may be due to the existence of flavin and lipopigment.


Subject(s)
Eccrine Glands/chemistry , Eccrine Glands/cytology , Flavins/analysis , Lipids/analysis , Microscopy, Fluorescence/methods , Skin/chemistry , Adult , Eosine Yellowish-(YS) , Female , Flavins/chemistry , Fluorescence , Hematoxylin , Humans , In Vitro Techniques , Lipids/chemistry , Male , Middle Aged
8.
Br J Radiol ; 88(1052): 20140693, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26081448

ABSTRACT

OBJECTIVE: To study age-related metabolic changes in different brain regions. METHODS: Point-resolved spectroscopy (repetition time/echo time = 2000 ms/30 ms) was performed in the left and right hippocampus, the left thalamus and the left centrum semiovale of 80 healthy subjects (37 females and 43 males aged 7-64 years). Analysis of covariance and linear regression were used for statistical analysis. Both metabolite concentration ratios with respect to total creatine (tCr) and absolute metabolite concentrations were included for analysis. RESULTS: Ins (myo-inositol)/tCr (p < 0.001) and absolute Ins concentration (p = 0.031) were significantly increased with age after adolescence. NAA (N-acetylaspartic acid)/tCr (p < 0.001) and absolute NAA concentration (p = 0.010) significantly declined with age after adolescence. CONCLUSION: Age-related increase of Ins and decline of NAA are found in all three regions, especially at the hippocampus, indicating possible gliosis in the ageing brain. ADVANCES IN KNOWLEDGE: We could use NAA/tCr and Ins/tCr as an indicator to estimate the neurons-to-glial cells ratio at the thalamus. This may be an index to distinguish normal tissues from gliosis.


Subject(s)
Brain/metabolism , Adolescent , Adult , Aging/physiology , Analysis of Variance , Aspartic Acid/analogs & derivatives , Aspartic Acid/metabolism , Child , Creatinine/metabolism , Female , Glutamic Acid/metabolism , Glutamine/metabolism , Healthy Volunteers , Humans , Inositol/metabolism , Magnetic Resonance Spectroscopy/methods , Male , Matrix Metalloproteinase 9/metabolism , Middle Aged , Young Adult
9.
Int J Immunopathol Pharmacol ; 25(4): 955-65, 2012.
Article in English | MEDLINE | ID: mdl-23298486

ABSTRACT

High mobility group box B1 (HMGB1)-receptor for advanced glycation end products (RAGE) axis has been previously known to be involved in carcinogenesis and development of multiple malignancies. Some studies have confirmed that Ethyl pyruvate (EP), a potent inhibitor of HMGB1, exerts the therapeutic effects on metastatic live tumor from gastric cancer. However, the effects and possible molecular mechanisms of EP on gallbladder cancer (GBC) need to be further explored. In the present study, human GBC cell lines (GBC-SD and SGC-996) were treated with different concentrations of EP. Then, the expression levels of HMGB1, RAGE and some transcription factors were identified by Real-time PCR and Western blot assays. Cell proliferative activities indicated by MTT assay, invasive potential by Transwell assay and cell apoptosis and cycle distribution were performed for functional analysis of GBC cell lines in vitro. As a result, EP decreased the expression of HMGB11, RAGE, PCNA and matrix metallopeptidase-9 (MMP-9), while it increased the expression of p53. Moreover, EP administration decreased GBC cell proliferation, inhibited the invasive potential, and induced apoptosis and cycle arrest in S phase in GBC cells. In conclusion, EP administration inhibits growth and invasion of gallbladder cancer cells possibly via down-regulation of the HMGB1-RAGE axis, suggesting that EP may play a critical role in the treatment of cancer in conjunction with other therapeutic agents.


Subject(s)
Gallbladder Neoplasms/drug therapy , HMGB1 Protein/antagonists & inhibitors , Pyruvates/pharmacology , Receptors, Immunologic/antagonists & inhibitors , Apoptosis/drug effects , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Down-Regulation , Gallbladder Neoplasms/pathology , HMGB1 Protein/genetics , Humans , Neoplasm Invasiveness , Receptor for Advanced Glycation End Products , Receptors, Immunologic/genetics
10.
J Hazard Mater ; 181(1-3): 187-92, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20557997

ABSTRACT

The photochemical decomposition of perfluorodecanoic acid (PFDeA) in water in the presence of persulfate ion (S(2)O(8)(2-)) and sulfur ion (S(2-)) was investigated under vacuum ultraviolet (VUV) light irradiation. PFDeA was decomposed under VUV light irradiation. With the addition of S(2)O(8)(2-) or S(2-), the photo-decomposition and defluorination of PFDeA were enhanced significantly. Sulfate radical anion (SO(4)(*-)) generated from photolysis of S(2)O(8)(2-) initiated PFDeA oxidation. While the S(2-) ion, acting as a *OH scavenger, enhanced the role of reduction pathway induced by aqueous electrons (e(aq)(-)). The shorter-chain perfluorocarboxylic acids (PFCAs), formed in a stepwise manner from longer-chain PFCAs, were identified as products by HPLC/MS.


Subject(s)
Decanoic Acids/radiation effects , Fluorocarbons/radiation effects , Photochemical Processes , Ultraviolet Rays , Carboxylic Acids , Decanoic Acids/chemistry , Fluorocarbons/chemistry , Photolysis , Solutions , Sulfates/chemistry , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/radiation effects
11.
J Eur Acad Dermatol Venereol ; 23(4): 433-7, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19335730

ABSTRACT

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease which is involved in T- and B-lymphocyte-mediated autoimmunity. Apoptosis contributes to the maintenance of lymphocytes homeostasis and the deletion of autoreactive cells in SLE. Although there is evidence that cellular FLICE-inhibitory protein (c-FLIP), an antiapoptosis protein, is increased in human lupus T cells to keep them from apoptosis, but the expression of apoptosis-regulatory protein c-FLIP in SLE B lymphocytes remains unknown. AIMS: To study the expression of c-FLIP in peripheral blood B lymphocytes in SLE patients and to investigate the relationship among the expression of c-FLIP in peripheral blood B lymphocytes in SLE patients, clinical manifestation and the levels of interleukin-4 (IL-4) and IL-10. METHODS: In this study, we detected the expression of c-FLIP in peripheral blood B lymphocytes in SLE patients by flow cytometry and the levels of IL-4 and IL-10 in SLE serum samples by enzyme-linked immunosorbent assay and analysed their relationship with clinical characteristics. RESULTS: We observed a significantly higher percentage of c-FLIP in peripheral B cells in SLE patients with active disease when compared to inactive ones and healthy controls. And the expression of c-FLIP in lupus peripheral B cells showed positive correlations with SLEDAI, erythrocyte sedimentation rate, C-reactive protein, antinucleosome antibody titre, IL-4, and IL-10, and negative correlation with white blood cell count. Patients with lupus nephritis had higher levels of c-FLIP in peripheral B cells than patients without lupus nephritis. CONCLUSION: Our data show that overexpression of c-FLIP is relevant to the activity and severity of SLE. Its overexpression might play a role in preventing B cell from apoptosis in SLE. The cause of c-FLIP overexpression may be due to the increase of IL-4 and IL-10 levels in SLE patients.


Subject(s)
B-Lymphocytes/metabolism , CASP8 and FADD-Like Apoptosis Regulating Protein/metabolism , Lupus Erythematosus, Systemic/metabolism , Up-Regulation , Adolescent , Adult , Aged , Female , Humans , Lupus Erythematosus, Systemic/blood , Male , Middle Aged , Young Adult
12.
J Chromatogr A ; 922(1-2): 139-49, 2001 Jul 13.
Article in English | MEDLINE | ID: mdl-11486859

ABSTRACT

This paper describes the first coupling of a commercial capillary HPLC system with a diode array spectrophotometric detector and a custom-built nuclear magnetic resonance (NMR) flow microprobe. The eluent from a 3-microm diameter C18 HPLC column is linked to a 500 MHz 1H-NMR microcoil probe with an observe volume of 1.1 microl. The separation and structurally-rich detection of a mixture of terpenoids under both isocratic and gradient solvent elution conditions is presented. The lowest limits of detection yet reported for capillary HPLC on-line measurement (i.e., 37 ng for alpha-pinene) are achieved with this system. The complementary nature of diode array and NMR detection allows stopped-flow data collection from analytes which would otherwise go unnoticed in continuous-flow NMR. Moreover, stopped-flow NMR data is presented for the detection of a trace (sub-nmol) impurity in the sample mixture. Since NMR signals degrade and shift during solvent gradients, flow injection analysis studies are conducted with injected solvent plugs differing in mobile phase composition. The NMR signal degradation accompanying these injections is largely due to the variance in chemical shift with the solvent composition rather than to changes in magnetic susceptibility of the solvent. Characterization of such effects enables the development of improved NMR probes for the coupling of capillary HPLC and NMR.


Subject(s)
Chromatography, High Pressure Liquid/methods , Magnetic Resonance Spectroscopy/methods , Terpenes/isolation & purification
13.
Article in English | MEDLINE | ID: mdl-11138141

ABSTRACT

A percolation model with long-range correlations was introduced to investigate the phenomena of epidemic spreading by Monte Carlo simulations. The correlation exponent alpha and pathogenic ratio s correspond to different spreading methods and pathogenicity of variant epidemics. As the correlation changes from a weak one to a strong one, the patterns change from site percolation to Eden cluster when pathogenic ratio s=1, or Leath percolation cluster when s<1. Corresponding to change of patterns, the fractal dimension increases up to space dimension. The critical behavior in epidemic spreading has been examined based on the model. It is found that correlation has a great influence on the threshold of spreading percolation.


Subject(s)
Disease Outbreaks/statistics & numerical data , Fractals , Humans , Models, Biological , Models, Statistical , Monte Carlo Method
14.
Sheng Li Xue Bao ; 52(5): 381-4, 2000 Oct.
Article in Chinese | MEDLINE | ID: mdl-11941391

ABSTRACT

Experiments were performed on freshly isolated dorsal root ganglion (DRG) neurons of rat. GABA(A)-activated currents were recorded using the whole-cell patch clamp technique. The majority of the neurons (48/52, 90.5%) were sensitive to GABA (10( 6)~10( 3) mol/L). Application of oxytocin (OT) induced outward membrane responses in 51.3% (20/39) of the neurons, no apparent responses in 43.6% (17/39) and inward responses in 5.1% (2/39). 10( 12), 10( 11), 10( 10) and 10( 9) mol/L OT increased 10( 4) mol/L GABA-activated currents to 24.1+/-7.6% (n=6), 33.4+/-6.9% (n=9), 40.2+/-6.5% (n=13) and 67.2+/-14.8% (n=5), respectively. After preapplication of OT, the Kd value for GABA(A)-activated currents decreased, while the response obtained at the maximum concentration increased. The results suggest that the enhancement of GABA-activated currents by OT may suppress primary sensory transmission by potentiating pre-synaptic inhibition of GABA.


Subject(s)
Ganglia, Spinal/physiology , Oxytocin/pharmacology , gamma-Aminobutyric Acid/pharmacology , Animals , Animals, Newborn , Cell Separation , Electrophysiology , Ganglia, Spinal/cytology , Male , Neurons/physiology , Rats , Rats, Wistar
15.
Anal Chem ; 71(23): 5335-9, 1999 Dec 01.
Article in English | MEDLINE | ID: mdl-10596212

ABSTRACT

An HPLC NMR system is presented that integrates a commercial microbore HPLC system using a 0.5-mm column with a 500-MHz proton NMR spectrometer using a custom NMR probe with an observe volume of 1.1 microL and a coil fill factor of 68%. Careful attention to capillary connections and NMR flow cell design allows on-line NMR detection with no significant loss in separation efficiency when compared with a UV chromatogram. HPLC NMR is performed on mixtures of amino acids and small peptides with analyte injection amounts as small as 750 ng; the separations are accomplished in less than 10 min and individual NMR spectra are acquired with 12 s time resolution. Stopped-flow NMR is achieved by diversion of the chromatographic flow after observation of the beginning of the analyte band within the NMR flow cell. Isolation of the compound of interest within the NMR detection cell allows multidimensional experiments to be performed. A stopped-flow COSY spectrum of the peptide Phe-Ala is acquired in 3.5 h with an injected amount of 5 micrograms.


Subject(s)
Chromatography, High Pressure Liquid/methods , Magnetic Resonance Spectroscopy/instrumentation , Amino Acids/chemistry , Magnetic Resonance Spectroscopy/methods , Peptides/chemistry , Spectrophotometry, Ultraviolet
16.
Article in English | MEDLINE | ID: mdl-11970534

ABSTRACT

The influence of particle size on diffusion-limited aggregation (DLA) has been investigated by computer simulations. For DLA clusters consisting of two kinds of particles with different sizes, when large particles are in the minority, the patterns of clusters appear asymmetrical and nonuniform, and their fractal dimensions D(f) increase compared with one-component DLA. With increasing size of large particles, D(f) increases. This increase can be attributed to two reasons: one is that large particles become new growth centers; the other is the big masses of large particles. As the concentration ratio x(n) of large particles increases, D(f) will reach a maximum value D(f(m)) and then decrease. When x(n) exceeds a certain value, the morphology and D(f) of the two-component DLA clusters are similar to those of one-component DLA clusters.

17.
Anal Chem ; 71(7): 248A-55A, 1999 Apr 01.
Article in English | MEDLINE | ID: mdl-21649059

ABSTRACT

Molecular imprint polymers recognize specific compounds and show promise as separation media, especially for chiral molecules.

18.
Electrophoresis ; 19(12): 2055-60, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9761181

ABSTRACT

Chiral separations employing molecular imprint polymer (MIP) stationary phases in both open tubular liquid chromatography (OT-LC) and capillary electrochromatography (OT-CEC) are demonstrated. MIPs are highly crosslinked polymers containing spatial and functionality memory of template molecules which provide a higher degree of selectivity when used as stationary phases for chromatographic separations. Thin films of molecular imprinted polymers bonded to the inner walls of 25 microm ID fused-silica capillaries were prepared using an in situ polymerization technique developed in our laboratory that allows the use of conventional fused-silica capillaries with polyimide outer coatings. The success rate in preparing such open tubular columns was about 70%. Methacrylic acid and 2-vinyl pyridine were chosen as functional monomers, and either ethylene dimethacrylate or trimethylol propane trimethacrylate was used as the crosslinker. Toluene was employed as the porogen. Effects of polymerization conditions on column preparation and chromatographic performance were studied. Enantiomeric separations of D- and L-dansyl phenylalanines were achieved in both OT-LC and OT-CEC modes with good selectivity and efficiencies. Both types of separations may be performed on the same column using a single commercial instrument.


Subject(s)
Chromatography, Liquid/methods , Chromatography/methods , Polymers , Capillary Action , Cross-Linking Reagents , Dansyl Compounds/chemistry , Dansyl Compounds/isolation & purification , Methacrylates , Microscopy, Electron, Scanning , Phenylalanine/chemistry , Phenylalanine/isolation & purification , Polymers/chemistry , Pyridines , Silicon Dioxide , Temperature , Time Factors
19.
Shanghai Kou Qiang Yi Xue ; 4(3): 179-80, 1995 Sep.
Article in Chinese | MEDLINE | ID: mdl-15160092
20.
J Tongji Med Univ ; 15(1): 41-4, 1995.
Article in English | MEDLINE | ID: mdl-7783263

ABSTRACT

In this study, microcomputer image processing and pattern recognition technology, and the knowledge of morphology and optical characteristics of Cryptococcus neoformans were used for identification of Cryptococcus neoformans. Four groups of mice were lethally infected with standard strain, Wuhan strain, American B-2643 strain and Var. Shanghainesis of the Cryptococcus neoformans. The samples collected included mice brain, lung, kidney, liver, small intestine tissue and were observed under a light microscope. More than 600 images of the fungus were input into a microcomputer. A system of computer for automatic identification of the Cryptococcus neoformans was developed. The technique involved image preprocessing, image segmenting, coding of line-length on the edge, curve fitting, extracting of image feature, building of image library and feature data bank etc.. And then, 768 images of the clinical samples and other fungus samples whose morphological features tend to be confused with Cryptococcus neoformans were input into microcomputer and subjected to automatic identification. The Cryptococcus neoformans was accurately identified within 15 min, and the consistency rate with results of routine culture was 98%.


Subject(s)
Cryptococcus neoformans/isolation & purification , Microcomputers , Animals , Cryptococcosis/diagnosis , Cryptococcosis/microbiology , Humans , Image Processing, Computer-Assisted , Mice , Pattern Recognition, Automated , Software Design
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