Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 64
Filter
1.
Ann Oncol ; 34(7): 578-588, 2023 07.
Article in English | MEDLINE | ID: mdl-37100205

ABSTRACT

BACKGROUND: We aim to implement an immune cell score model in routine clinical practice for resected non-small-cell lung cancer (NSCLC) patients (NCT03299478). Molecular and genomic features associated with immune phenotypes in NSCLC have not been explored in detail. PATIENTS AND METHODS: We developed a machine learning (ML)-based model to classify tumors into one of three categories: inflamed, altered, and desert, based on the spatial distribution of CD8+ T cells in two prospective (n = 453; TNM-I trial) and retrospective (n = 481) stage I-IIIA NSCLC surgical cohorts. NanoString assays and targeted gene panel sequencing were used to evaluate the association of gene expression and mutations with immune phenotypes. RESULTS: Among the total of 934 patients, 24.4% of tumors were classified as inflamed, 51.3% as altered, and 24.3% as desert. There were significant associations between ML-derived immune phenotypes and adaptive immunity gene expression signatures. We identified a strong association of the nuclear factor-κB pathway and CD8+ T-cell exclusion through a positive enrichment in the desert phenotype. KEAP1 [odds ratio (OR) 0.27, Q = 0.02] and STK11 (OR 0.39, Q = 0.04) were significantly co-mutated in non-inflamed lung adenocarcinoma (LUAD) compared to the inflamed phenotype. In the retrospective cohort, the inflamed phenotype was an independent prognostic factor for prolonged disease-specific survival and time to recurrence (hazard ratio 0.61, P = 0.01 and 0.65, P = 0.02, respectively). CONCLUSIONS: ML-based immune phenotyping by spatial distribution of T cells in resected NSCLC is able to identify patients at greater risk of disease recurrence after surgical resection. LUADs with concurrent KEAP1 and STK11 mutations are enriched for altered and desert immune phenotypes.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/surgery , Lung Neoplasms/genetics , Lung Neoplasms/surgery , Retrospective Studies , Kelch-Like ECH-Associated Protein 1/genetics , Prospective Studies , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Neoplasm Recurrence, Local , Prognosis , Phenotype , Mutation , AMP-Activated Protein Kinase Kinases
2.
J Allergy Clin Immunol ; 147(1): 92-98, 2021 01.
Article in English | MEDLINE | ID: mdl-32971109

ABSTRACT

BACKGROUND: The pathogenesis of coronavirus disease 2019 (COVID-19) is still incompletely understood, but it seems to involve immune activation and immune dysregulation. OBJECTIVE: We examined the parameters of activation of different leukocyte subsets in COVID-19-infected patients in relation to disease severity. METHODS: We analyzed plasma levels of myeloperoxidase (a marker of neutrophil activation), soluble (s) CD25 (sCD25) and soluble T-cell immunoglobulin mucin domain-3 (sTIM-3) (markers of T-cell activation and exhaustion), and sCD14 and sCD163 (markers of monocyte/macrophage activation) in 39 COVID-19-infected patients at hospital admission and 2 additional times during the first 10 days in relation to their need for intensive care unit (ICU) treatment. RESULTS: Our major findings were as follows: (1) severe clinical outcome (ICU treatment) was associated with high plasma levels of sTIM-3 and myeloperoxidase, suggesting activated and potentially exhausted T cells and activated neutrophils, respectively; (2) in contrast, sCD14 and sCD163 showed no association with need for ICU treatment; and (3) levels of sCD25, sTIM-3, and myeloperoxidase were inversely correlated with degree of respiratory failure, as assessed by the ratio of Pao2 to fraction of inspired oxygen, and were positively correlated with the cardiac marker N-terminal pro-B-type natriuretic peptide. CONCLUSION: Our findings suggest that neutrophil activation and, in particular, activated T cells may play an important role in the pathogenesis of COVID-19 infection, suggesting that T-cell-targeted treatment options and downregulation of neutrophil activation could be of importance in this disorder.


Subject(s)
COVID-19/blood , Hepatitis A Virus Cellular Receptor 2/blood , SARS-CoV-2/metabolism , Aged , Antigens, CD/blood , Antigens, Differentiation, Myelomonocytic/blood , Female , Humans , Interleukin-2 Receptor alpha Subunit/blood , Lipopolysaccharide Receptors/blood , Lymphocyte Activation , Male , Middle Aged , Receptors, Cell Surface/blood , Severity of Illness Index , T-Lymphocytes/metabolism , Time Factors
3.
J Eur Acad Dermatol Venereol ; 34(2): 333-339, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31419348

ABSTRACT

BACKGROUND: Methylisothiazolinone (MI) has caused an unprecedented epidemic of contact allergy in Europe and elsewhere. Subsequently, regulatory action has been taken, at least in Europe, aiming at reducing risk of MI sensitization. OBJECTIVE: To follow-up on the prevalence of contact allergy to MI in consecutively patch tested patients and assess the spectrum of products containing MI or methylchloroisothiazolinone (MCI)/MI in patients positive to MI which elicited current allergic contact dermatitis. METHODS: A cross-sectional survey was performed in 2016 and 2017, including all adult patients patch tested with the baseline series (including MI 0.2% aq.) between 1 May and 31 October at 14 centres in 11 European countries. Patients with positive reactions (+ to +++) to MI were further examined regarding history, clinical characteristics and eliciting products, which were categorized into 34 types and 4 classes (leave-on, rinse-off, household, occupational). The results were compared with the reference year 2015. RESULTS: A total of 317 patients, n = 202 of 4278 tested in 2016 (4.72%) and n = 115 of 3879 tested in 2017 (2.96%), had positive reactions to MI; the previous result from 2015 was 5.97% (P < 0.0001). The share of currently relevant contact allergy among all positive reactions declined significantly as well (P = 0.0032). Concerning product classes, a relative decline of leave-on and a relative increase of rinse-off and household products was noted. CONCLUSION: The prevalence of MI contact allergy decreased by 50% from 2015 to 2017. As a consequence of regulation, the share of cosmetics products (leave-on in particular) eliciting allergic contact dermatitis is decreasing. The chosen method of analysing causative products in sensitized patients has proven useful to monitor effects of intervention.


Subject(s)
Dermatitis, Contact/epidemiology , Thiazoles/adverse effects , Adolescent , Adult , Child , Child, Preschool , Dermatitis, Contact/etiology , Europe/epidemiology , Female , Follow-Up Studies , Humans , Infant , Male , Middle Aged , Patch Tests , Young Adult
4.
Ann Oncol ; 27(2): 225-32, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26578726

ABSTRACT

Immunoscore is a prognostic tool defined to quantify in situ immune cell infiltrates and appears highly promising as a supplement to the tumor-node-metastasis (TNM) classification of various tumors. In colorectal cancer, an international task force has initiated prospective multicenter studies aiming to implement TNM-Immunoscore (TNM-I) in a routine clinical setting. In breast cancer, recommendations for the evaluation of tumor-infiltrating lymphocytes (TILs) have been proposed by an international working group. Regardless of promising results, there are potential obstacles related to implementing TNM-I into the clinic. Diverse methods may be needed for different malignancies and even within each cancer entity. Nevertheless, a uniform approach across malignancies would be advantageous. In nonsmall-cell lung cancer (NSCLC), there are several previous reports indicating an apparent prognostic importance of TILs, but studies on TILs in a TNM-I setting are sparse and no general recommendations are made. However, recently published data is promising, evoking a realistic hope of a clinical useful NSCLC TNM-I. This review will focus on the TNM-I potential in NSCLC and propose strategies for clinical implementation of a TNM-I in resected NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung/pathology , Lung Neoplasms/pathology , Lymphocytes, Tumor-Infiltrating/pathology , Carcinoma, Non-Small-Cell Lung/diagnosis , Carcinoma, Non-Small-Cell Lung/mortality , Humans , Lung Neoplasms/diagnosis , Lung Neoplasms/mortality , Lymphocytes, Tumor-Infiltrating/immunology , Neoplasm Metastasis/diagnosis , Neoplasm Metastasis/pathology , Neoplasm Staging , Prognosis , Severity of Illness Index , Tumor Microenvironment/immunology
5.
Br J Dermatol ; 160(6): 1229-36, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19416249

ABSTRACT

BACKGROUND: Hand eczema (HE) is a frequent, long-lasting disease with both personal and societal repercussions. Consequently, more information is needed on factors that maintain symptoms. OBJECTIVES: In this study, patients with HE were followed for 6 months from the first visit to a dermatologist to identify factors associated with severe disease and a poor prognosis. METHODS: Study participants were 799 patients with HE from nine dermatological clinics in Denmark. Severity assessment of the HE was done at baseline and at the 6-month follow-up using the Hand Eczema Severity Index (HECSI) and by patients using a self-administered photographic guide. Additional information was obtained from a baseline questionnaire. RESULTS: At baseline, 60.3% assessed their HE as moderate to very severe using the self-administered photographic guide compared with 36.1% at follow-up. The mean HECSI value decreased from 19.9 points at baseline to 11.2 points at follow-up (P < 0.001). In a multivariable logistic regression analysis, statistically significant associations with severe HE at baseline were older age (P < 0.001), atopic dermatitis (P = 0.01) and > or = 1 positive patch test (P < 0.001). Being an unskilled worker was a predictor for a poor prognosis at follow-up (P = 0.04), and the presence of frequent symptoms during the previous 12 months was associated with severe initial disease (P = 0.02) and a poor prognosis (P = 0.04). CONCLUSIONS: Overall, the disease had improved 6 months after the dermatological examination: nevertheless, many patients continued to have significant symptoms. Dermatologists should pay special attention to patients with frequent eruptions and to unskilled workers.


Subject(s)
Eczema/diagnosis , Hand Dermatoses/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , Eczema/psychology , Female , Follow-Up Studies , Hand Dermatoses/psychology , Humans , Male , Middle Aged , Photography , Prognosis , Prospective Studies , Regression Analysis , Severity of Illness Index , Surveys and Questionnaires , Young Adult
10.
Br J Dermatol ; 156(3): 510-5, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17300241

ABSTRACT

BACKGROUND: Compositae dermatitis confined to exposed skin has often been considered on clinical grounds to be airborne. Although anecdotal clinical and plant chemical reports suggest true airborne allergy, no proof has been procured. Feverfew (Tanacetum parthenium) is a European Compositae plant suspected of causing airborne contact allergy, and its most important allergen is the sesquiterpene lactone (SQL) parthenolide (PHL). OBJECTIVES: The aims of this study were to (i) assess the allergenicity of feverfew-derived monoterpenes and sesquiterpenes and their oxidized products in feverfew-allergic patients and (ii) re-assess the role of PHL and other SQLs in airborne contact allergy. PATIENTS AND METHODS: Feverfew-allergic patients were patch tested with extracts and fractions containing volatile monoterpenes and sesquiterpenes as well as extracts of airborne particles from flowering feverfew plants, obtained by fractionation of ether extracts, dynamic headspace and high-volume air sampler (HIVAS) technique, respectively. RESULTS: Among 12 feverfew-allergic patients, eight had positive patch-test reactions to a HIVAS filter extract, while two tested positive to a headspace extract. Subsequent analysis of the HIVAS extract by gas chromatography and mass spectrometry detected PHL in a concentration of 510 ng mL(-1) in the HIVAS extract. Testing with a dilution series of PHL showed positive reactions down to 8.1 ng in selected patients. None of the 12 patients tested positive to monoterpenes or sesquiterpenes, whether they were oxidized or not. CONCLUSIONS: The clinical results have proved that some feverfew-allergic patients are sensitive to airborne particles released from the plant, and isolation of PHL from the particle-containing HIVAS extract in allergenic amounts is strong evidence of PHL as the responsible allergen.


Subject(s)
Air Pollutants/immunology , Dermatitis, Allergic Contact/etiology , Sesquiterpenes/immunology , Tanacetum parthenium/immunology , Adult , Aged , Air Pollutants/analysis , Allergens/analysis , Allergens/immunology , Environmental Monitoring/methods , Female , Gas Chromatography-Mass Spectrometry/methods , Humans , Male , Middle Aged , Patch Tests , Sesquiterpenes/analysis , Volatilization
11.
Contact Dermatitis ; 53(5): 285-91, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16283907

ABSTRACT

The aim of this study was to assess the strength of any association between sensitization to 'new' fragrance compounds and sensitization to Compositae, fragrance mix, Myroxylon pereirae resin and colophonium, respectively. Consecutive eczema patients were tested with a series of essential oils and selected fragrance compounds and another series of oxidized terpenes in connection with European multicentre fragrance projects. Contact allergy to either series was frequently detected, in 5% of 318 and 4.6% of 262 persons tested, and both had a statistically significant association with Compositae, colophonium and fragrance mix sensitization. The individual results indicated that simultaneously occurring positive reactions to essential oils, colophonium and Compositae were based on cross-reactivity rather than concomitant sensitization. Thus, all patients with positive reaction to the rare fragrance sensitizer beta-caryophyllene had positive colophonium reactions, and cross-reactivity between essential oils and Compositae was related to the Compositae plant extracts of the Compositae mix and not the pure sesquiterpene lactones of the standard series. The implication is that Compositae mix and colophonium may be markers of fragrance allergy, which is important to know when assessing the relevance of positive reactions to Compositae plant extracts and colophonium.


Subject(s)
Asteraceae/immunology , Cross Reactions , Dermatitis, Allergic Contact/etiology , Myroxylon/immunology , Perfume/adverse effects , Plant Extracts/adverse effects , Adult , Aged , Asteraceae/adverse effects , Biomarkers , Dermatitis, Allergic Contact/immunology , Female , Humans , Male , Middle Aged , Myroxylon/adverse effects , Oils, Volatile/adverse effects , Polycyclic Sesquiterpenes , Resins, Plant/adverse effects , Retrospective Studies , Sesquiterpenes/adverse effects , Sesquiterpenes/immunology , Skin Tests , Terpenes/adverse effects , Terpenes/immunology
12.
J Eur Acad Dermatol Venereol ; 19(3): 326-31, 2005 May.
Article in English | MEDLINE | ID: mdl-15857459

ABSTRACT

BACKGROUND: The Aloe vera plant has been used for an array of ailments, including skin diseases. Recent experimental research have substantiated the presence of biologically active compounds in the gel, but there are few controlled, clinical trials to assess the efficacy. OBJECTIVE: To test the effect of a commercial, preserved, but otherwise untreated Aloe vera gel in psoriasis. PATIENTS/METHODS: Forty-one patients with stable plaque psoriasis were included in a randomized, double-blind, placebo-controlled right/left comparison. The study comprised a 2-week wash-out period followed by a 4-week treatment period with two daily applications and follow-up visits after 1 and 2 months. RESULTS: Data on 40 patients were analysed. The score sum of erythema, infiltration and desquamation decreased in 72.5% of the Aloe vera-treated sites compared with 82.5% of the placebo-treated areas from week 0 to week 4, which was statistically significant in favour of the placebo treatment (P = 0.0197). Fifty-five per cent of the patients reported local side-effects, mainly drying up of the skin on test areas. CONCLUSIONS: The effect of this commercial Aloe vera gel on stable plaque psoriasis was modest and not better than placebo. However, the high response rate of placebo indicated a possible effect of this in its own right, which would make the Aloe vera gel treatment appear less effective.


Subject(s)
Aloe , Plant Preparations/therapeutic use , Psoriasis/drug therapy , Adult , Aged , Double-Blind Method , Female , Follow-Up Studies , Gels , Humans , Male , Middle Aged
13.
Contact Dermatitis ; 47(1): 14-8, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12225407

ABSTRACT

The Compositae plant feverfew (Tanacetum parthenium) is an important sensitizer in Europe and has been suspected of causing airborne Compositae dermatitis. A previous investigation of substances emitted from feverfew plants detected no sesquiterpene lactones, however, but mainly monoterpenes. The aims of this study were to test whether feverfew-allergic patients were also sensitive to some of the above-mentioned monoterpenes and, if so, to study associations between sensitization patterns, relevance of feverfew allergy and clinical features. 17 patients with + +/+ + + reactions to feverfew and parthenolide were tested with 15 selected monoterpenes and 2 sesquiterpenes. Of the 17 persons, 13 had positive and/or doubtful positive reactions to 1 or more monoterpenes. Only 1 person was allergic to several monoterpenes. Her history of gradually worsening Compositae dermatitis culminating in a probable airborne dermatitis, mimicking photosensitivity, and the disappearance of symptoms upon removal of feverfew plants suggest monoterpenes as a possible contributing factor. Similar associations between doubtful positive monoterpene reactions and clinical patterns, fragrance/colophonium allergy and relevance of feverfew allergy were not established with certainty. In conclusion, sensitization to the sesquiterpene lactones of feverfew is not invariably accompanied by sensitization to its volatile monoterpenes. The presence of monoterpene allergy, however, may contribute to airborne Compositae dermatitis.


Subject(s)
Allergens/adverse effects , Dermatitis, Allergic Contact/diagnosis , Facial Dermatoses/diagnosis , Monoterpenes/adverse effects , Oils, Volatile/adverse effects , Tanacetum parthenium , Adult , Aged , Aged, 80 and over , Dermatitis, Allergic Contact/etiology , Facial Dermatoses/chemically induced , Female , Humans , Male , Middle Aged
14.
Contact Dermatitis ; 45(4): 197-204, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11683829

ABSTRACT

Results of aimed patch testing with constituents of sesquiterpene lactone (SL) mix, Compositae mix (CM) and other Compositae extracts and allergens in 190 Compositae-allergic patients detected in an 8-year period are presented. Feverfew of CM elicited positive reactions most frequently, followed by tansy, wild chamomile, yarrow and arnica, whereas dehydrocostus lactone of SL was the most frequent elicitor of positive reactions, followed by alantolactone and costunolide. Chrysanthemum (Dendranthema) and marguerite (Argyranthemum frutescens) were the most important suspected sensitizers in both occupationally and nonoccupationally exposed, and cross-reactions between chrysanthemum and feverfew/tansy/chamomile may partly explain the high prevalence of positive reactions to the 3 last mentioned. In the nonoccupationally sensitized group, garden plants such as feverfew, blanket flower (Gaillardia), elecampane (Inula helenium), large yellow ox-eye (Telekia speciosa) and cosmea (Cosmos) were additional important allergenic plants. The 3 last mentioned were picked up by SL mix. Most of the lettuce-sensitized persons were CM-positive. 19% of the occupationally sensitized group were negative to both SL and CM, making very aimed patch testing necessary, notably when suspecting rare sensitizers such as Gerbera and star of the veldt (Osteospermum). The significance of the weeds dandelion, dog fennel and ox-eye daisy as sensitizers is not clarified, but they are probably less important than cultivated plants.


Subject(s)
Dermatitis, Allergic Contact/diagnosis , Inula/immunology , Sesquiterpenes/immunology , Adult , Allergens , Dermatitis, Allergic Contact/etiology , Female , Humans , Male , Middle Aged , Patch Tests , Plant Extracts/immunology
15.
Contact Dermatitis ; 45(1): 29-35, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11422265

ABSTRACT

Routine patch testing with sesquiterpene lactone (SL) mix, supplemented with Compositae mix (CM) and other Compositae extracts and allergens where appropriate, was evaluated over an 8-year period. 190 of 4386 patients tested (4.3%) were Compositae-sensitive, 143 females (mean age 51.5 years) and 47 males (mean age 55 years), and 83% of reactions considered clinically relevant. 22% were suspected of occupational sensitization/dermatitis. 62% had a contact allergy to 2 or more compounds, most often to nickel, fragrance and colophonium. SL mix detected 65%, CM 87% of Compositae-allergic patients, and the overall detection rate with both mixes was 93%. Few irritant reactions and no cases of clear-cut active sensitization were recorded with the mixes, but our results emphasize the importance of differentiating late-appearing reactivation reactions from patch test sensitization. The weakly positive CM reactions could reflect some irritancy, but as they were associated with fragrance and/or colophonium allergy to a higher degree than weakly positive SL mix reactions, they probably represented cross-reactions. In conclusion, the detection rate with SL mix was high enough to support its continued use as a screening mix and it was very well and rather safely supplemented by aimed testing with CM.


Subject(s)
Allergens/adverse effects , Asteraceae/adverse effects , Dermatitis, Allergic Contact/epidemiology , Dermatitis, Allergic Contact/etiology , Dermatitis, Occupational/epidemiology , Dermatitis, Occupational/etiology , Patch Tests/standards , Sesquiterpenes/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Denmark/epidemiology , Dermatitis, Allergic Contact/diagnosis , Dermatitis, Occupational/diagnosis , Female , Humans , Male , Middle Aged , Plant Extracts/adverse effects , Prevalence
16.
Am J Surg ; 182(6): 570-7, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11839319

ABSTRACT

BACKGROUND: This study was undertaken to determine if thoracic epidural analgesia is of practical benefit after bowel resection. METHODS: Patients were prospectively randomized to receive either a thoracic epidural or patient-controlled analgesia for pain control after bowel resection. A standardized postoperative protocol was instituted after surgery. RESULTS: Pain scores were significantly lower in the epidural group. Return of bowel function, and interval to discharge was not different between groups. Cost and complication rates were significantly higher in the epidural group. CONCLUSIONS: Although pain scores were significantly lower in the epidural group, this did not translate into a quicker return of bowel function or earlier discharge of the patient. Furthermore, the epidural group had a significantly higher complication rate and cost. Therefore, while thoracic epidural analgesia provides superior pain control, it does not offer a significant advantage over patient-controlled analgesia in return of bowel function after bowel resection.


Subject(s)
Analgesia, Epidural , Analgesia, Patient-Controlled , Intestines/surgery , Costs and Cost Analysis , Elective Surgical Procedures , Female , Humans , Length of Stay , Male , Middle Aged , Pain Measurement , Postoperative Care , Postoperative Complications , Prospective Studies , Thorax
17.
Biotechnol Prog ; 16(6): 1071-8, 2000.
Article in English | MEDLINE | ID: mdl-11101336

ABSTRACT

A variety of contactor types have been assessed for the liquid-liquid extraction of proteins using reversed micelles; however, many of these contactors suffer from drawbacks such as emulsion formation and poor mass transfer performance. In this study, a small (1.25 L) Graesser "raining bucket" contactor was assessed for use with this system since it has the potential to ameliorate many of these problems. The aim of the work was to evaluate the hydrodynamics of the contactor in order to use this information for future work on mass transfer performance. Hydrodynamic characteristics such as the axial mixing coefficient were determined by residence time distribution studies using a tracer injection method. The effect of rotor speed and flow rate of each phase on axial mixing was investigated, and as a result of its unusual structure, i.e., falling/rising sheet, the interfacial mass transfer area in the Graesser was determined by image analysis. It was found that rotor speed had more influence on the axial mixing coefficient in the aqueous phase than in the reverse micellar phase. The axial mixing coefficient in each phase increased by increasing the flow rate of the same phase. The images obtained in a dropping cell showed that under the conditions of this study (3 rpm, 22 degrees C), the bucket pours one phase through the other in the form of a curtain or sheet. A new image technique was developed to determine the interfacial area of both phases, and it was found that the specific area was 8.6 m(2)/m(3), which was higher than in a spray column but considerably lower than in a RDC or a Graesser run at high rotational speed (50 rpm) without the addition of a surfactant.


Subject(s)
Micelles , Proteins/isolation & purification , Equipment Design
18.
Biotechnol Bioeng ; 69(6): 618-26, 2000 Sep 20.
Article in English | MEDLINE | ID: mdl-10918136

ABSTRACT

The gentle mixing characteristics of a Graesser contactor can help to avoid the formation of stable emulsions, which is one advantage of this type of contactor when used with reversed micellar extraction. In this study, the performance of the Graesser contactor in lysozyme extraction from hen egg white is investigated. The concentration profile of lysozyme in the aqueous and organic phases indicated that, while substantial axial mixing occurred in the contactor, the extraction yield was in the range of 97% to 99%. The number of mass transfer units (N(ox)) was determined using a diffusion model, and the influence of aqueous-to-organic phase flow ratio, rotor speed, and total throughput on contactor performance was studied. It was found that the diffusion model could describe quite well the extraction of lysozyme from hen egg white using reversed micelles. The optimal conditions for the extraction at steady state were found to be a rotor speed of 5 rpm, an aqueous-to-organic phase flow ratio of 60:20 mL/min, and a total throughput of 80 mL/min. In addition, back-extraction was also performed using the conventional method (1.5 M KBr at pH 11.5) in the contactor. It was found that this mass transfer was not well described by a diffusion model, although 85% of the lysozyme could be recovered with the operating conditions used: a rotor speed of 10 rpm, and an aqueous-to-organic flow rate of 10:10 mL/min.


Subject(s)
Biotechnology/instrumentation , Biotechnology/methods , Muramidase/isolation & purification
19.
Bioseparation ; 9(2): 81-91, 2000.
Article in English | MEDLINE | ID: mdl-10892541

ABSTRACT

The liquid-liquid extraction of protein from buffered aqueous phases using reverse micelles (RM) has been extensively researched from a fundamental point of view. However, very little effort has been expended at scaling up this process for the extraction of real fermentation broth. When real broths are used with reverse micellar phases there are major problems with emulsion formation. In this study the effect of a variety of demulsifiers on lysozyme extraction was evaluated in terms of their influence on the separating properties of the emulsion, water content (Wo), and, extraction yield and kinetics from both buffer and hen egg white. In addition, the use of a low shear contactor (a Graesser or 'raining bucket') was assessed in terms of its suitability as a RM contactor. It was found that most of the demulsifiers reduced the settling time of the emulsion, and enhanced the yield and kinetics of lysozyme extraction from hen egg white. It was hypothesised that this was due to the demulsifier displacing the lysozyme from the interface and preventing the protein unfolding and precipitating. This effect was found to depend on both the generic type of demulsifier, and its concentration.


Subject(s)
Muramidase/isolation & purification , Animals , Biotechnology , Buffers , Female , Indicators and Reagents , Micelles , Ovum/enzymology
20.
J Biomol NMR ; 16(3): 209-19, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10805127

ABSTRACT

We demonstrate that high-resolution multidimensional solid state NMR methods can be used to correlate many backbone and side chain chemical shifts for hydrated micro-crystalline U-13C,15N Basic Pancreatic Trypsin Inhibitor (BPTI), using a field strength of 800 MHz for protons, magic angle sample spinning rates of 20 kHz and proton decoupling field strengths of 140 kHz. Results from two homonuclear transfer methods, radio frequency driven dipolar recoupling and spin diffusion, were compared. Typical 13C peak line widths are 0.5 ppm, resulting in Calpha-Cbeta and Calpha-CO regions that exhibit many resolved peaks. Two-dimensional carbon-carbon correlation spectra of BPTI have sufficient resolution to identify and correlate many of the spin systems associated with the amino acids. As a result, we have been able to assign a large number of the spin systems in this protein. The agreement between shifts measured in the solid state and those in solution is typically very good, although some shifts near the ion binding sites differ by at least 1.5 ppm. These studies were conducted with approximately 0.2 to 0.4 micromol of enriched material; the sensitivity of this method is apparently adequate for other biological systems as well.


Subject(s)
Aprotinin/chemistry , Carbon Isotopes , Models, Molecular , Nitrogen Isotopes , Nuclear Magnetic Resonance, Biomolecular
SELECTION OF CITATIONS
SEARCH DETAIL
...