Assessment of early anthracycline-induced cardiotoxicity and liver injury with T2 and T2* mapping in rabbit models

OBJECTIVES

To evaluate the early prevalence of anthracycline-induced cardiotoxicity (AIC) and anthracycline-induced liver injury (AILI) using T2 and T2* mapping and to explore their correlations.

MATERIALS AND METHODS

The study included 17 cardiotoxic rabbits that received weekly injections of doxorubicin and magnetic resonance imaging (MRI) every 2 weeks for 10 weeks. Cardiac function and T2 and T2* values were measured on each period. Histopathological examinations for two to five rabbits were performed after each MRI scan. The earliest sensitive time and the threshold of MRI parameters for detecting AIC and AILI based on these MRI parameters were obtained. Moreover, the relationship between myocardial and liver damage was assessed.

RESULTS

Early AIC could be detected by T2 mapping as early as the second week and focused on the 7th, 11th, and 12th segments of left ventricle. The cutoff value of 46.64 for the 7th segment had the best diagnostic value, with an area under the curve (of 0.767, sensitivity of 100%, and specificity of 52%. T2* mapping could detect the change in iron content for early AIC at the middle interventricular septum and AILI as early as the sixth week (p = 0.014, p = 0.027). The T2* values of the middle interventricular septum showed a significant positive association with the T2* values of the liver (r = 0.39, p = 0.002).

CONCLUSION

T2 and T2* mapping showed value one-stop assessment of AIC and AILI and could obtain the earliest MRI diagnosis point and optimal parameter thresholds for these conditions.

CLINICAL RELEVANCE STATEMENT

Anthracycline-induced cardiotoxicity could be detected by T2 mapping as earlier as the second week, mainly focusing on the 7th, 11th, and 12th segments of left ventricle. Combined with T2* mapping, hepatoxicity and supplementary cardiotoxicity were assessed by one-stop scan.

KEY POINTS

• MRI screening time of cardiotoxicity was as early as the second week with focusing on T2 values of the 7th, 11th, and 12th segments of left ventricle. • T2* mapping could be used as a complement to T2 mapping to evaluate cardiotoxicity and as an effective index to detect iron change in the early stages of chemotherapy. • The T2* values of the middle interventricular septum showed a significant positive association with the T2* values of the liver, indicating that iron content in the liver and heart increased with an increase in the chemotherapeutic drugs.

Assessment of early anthracycline-induced cardiotoxicity using segmental strain of cardiac magnetic resonance compared with global strain and functional parameters: an animal study

Background

The identification of anthracycline-induced cardiotoxicity holds significant importance in guiding subsequent treatment strategies, and recent research has demonstrated the efficacy of cardiac magnetic resonance (CMR) global strain analysis for its diagnosis. On the other hand, it is noteworthy that abnormal global myocardial strain may exhibit a temporal delay due to different cardiac movement in each segment of the left ventricle. To address this concern, this study aims to assess the diagnostic utility of CMR segmental strain analysis as an early detection method for cardiotoxicity.

Methods

A serials of CMR scans were performed in 18 adult males New Zealand rabbits at baseline time (n=15), followed by scans at week 2 (n=15), week 4 (n=9), week 6 (n=6), and week 8 (n=5) after each week's anthracycline injection. Additionally, following each CMR scan, two to three rabbits were euthanized for pathological comparison. Cardiac functional parameters, global peak strain parameters, segmental peak strain parameters of the left ventricle, and the presence of myocardial cells damage were obtained. A mixed linear model was employed to obtain the earliest CMR diagnostic time. Receiver operating characteristic (ROC) analysis was performed to get the parameter threshold indicative of cardiotoxicity.

Results

The left ventricular ejection fraction decreased at week 8 (P=0.002). There were no statistical differences in global strain throughout the experiment period (P>0.05). Regarding segmental strain analysis, the peak segmental radial strain of the apical lateral wall exhibited a decrease starting from week 2 and reached its lowest point at this week (P=0.011). Conversely, peak segmental circumferential strain of the apical anterior wall showed an increase at week 2 and reached its peak at week 6 (P=0.026). The cutoff strain value by ROC analysis for these two walls were 46.285 and -16.920, with the respective areas under the curve (AUC) 0.593 [specificity =0.267, sensitivity =1.000, 95% confidence interval (CI): 0.471-0.777] and 0.764 (specificity =0.733, sensitivity =0.784, 95% CI: 0.511-0.816). Peak segmental longitudinal strain of the apical anterior and apical lateral wall showed relatively delayed changes, occurring in the 4th week (P=0.030 and P=0.048), the cutoff values for these strains were -12.415 and -15.960, with corresponding AUCs of 0.645 (specificity =0.333, sensitivity =0.955, 95% CI: 0.495-0.795) and 0.717 (specificity =0.433, sensitivity =0.955, 95% CI: 0.566-0.902), respectively. Notably, the myocardial injury was also observed at the corresponding periods.

Conclusions

Based on experimental evidence, the peak segmental strain of the apical lateral and anterior wall, as determined by CMR, demonstrated an earlier detection of anthracycline-induced cardiotoxicity compared to peak global strain and cardiac function.

[Efficacy analysis of fully endoscopic microvascular decompression in primary trigeminal neuralgia via keyhole approach]

Objective: To explore the efficacy and technical features of fully endoscopic microvascular decompression(MVD) in primary trigeminal neuralgia(PTN) via keyhole approach. Methods: The clinical data of 97 patients with PTN underwent fully endoscopic MVD via keyhole approach in the Department of Neurosurgery, Beijing Shijitan Hospital, Capital Medical University from December 2014 to February 2019 was collected. During fully endoscopic MVD in PTN via keyhole approach, performer use natural clearance without grinding except developed rock bone crest or excessive retraction of the brain tissue, visually and panoramically observe and evaluate the CPA area, accurately identify the responsible vessels, to avoid the omission of responsible vessels or insufficient decompression. And the use of preplaced technology, bridging technology and submersible technology, ensure the efficacy of surgery and reduce the surgical side injuries.Barrow Neurological Institute (BNI) pain score was used to evaluate the efficacy and identify the recurrence. The surgical efficacy was analyzed. Results: The offending vessels were identified under endoscope in 96 cases. Among them, arterial compression was found in 77 cases, venous compression in 6 cases, and both arterial and venous compression in 13 cases. About the pain outcomes, 87 cases had immediate and complete relief of pain, 5 cases had almost relief of pain, 4 cases had partial relief of pain, and still needed medication control, but the dose was lower than that before operation, and 1 case had no obvious relief of pain. About complications, there were 4 cases of temporary facial numbness, 1 case of temporary hearing loss, both of them recovered after symptomatic treatment. There was no cerebral infarction or hemorrhage, intracranial or incision infection. All cases were followed up for 3.0-38.0 months with a median period of(22.4±2.2) months. During the follow-up periods, postoperative recurrence occurred in 3 cases. Conclusion: Fully endoscopic MVD for PTN through keyhole approach, provides panoramic view to avoid omission of offending vessels and reduce complications, seemed to be a safe and effective surgical method.

[Value of dynamic MRI in monitoring the microenvironmental changes of anti-vascular therapy in a xenograft model]

Objective: To explore the feasibility of dynamic-enhanced magnetic resonance imaging (DCE-MRI) and blood oxygen level-dependent MRI (BOLD-MRI) in assessing the hemodynamics and tumor aggressiveness during treatment. Methods: The colon cancer xenograft model was established in BALB/C nude mice with HCT116 cell line. Sixteen nude mice were randomly divided into treatment and control groups (aged 6 to 8 weeks, weighted 15 to 18 g, Certificate No. 11400700325797), which were treated with bevacizumab and saline by intraperitoneal injection on the 1st, 4th, 7th, 10th and 13th day. DCE-MRI and BOLD-MRI were performed before and on the 3th, 6th, 9th, 12th, and 15th day after treatment. The vascular maturity and microenvironment hypoxia were confirmed by pathology. Results: The tumor volume of treatment group was significantly smaller than that of control group after 15 days ((712±43) vs (1 051±112) mm(3),P<0.01).The measurements of K(trans) were (0.135±0.005),(0.147±0.006),(0.175±0.009),(0.161±0.006), (0.140±0.005),(0.116±0.008)/min (F=81.386, P<0.01); K(ep) were (0.788±0.030),(0.804±0.036),(0.983±0.059), (1.105±0.091),(0.840±0.047),(0.786±0.041)/min(F=45.901,P<0.01);Ve were (0.652±0.006), (0.559±0.026), (0.466±0.016), (0.286±0.027), (0.363±0.020), (0.246±0.033) (F=384.290, P<0.01) and R2* values were (24.813±0.961), (24.675±1.070), (21.425±1.371), (17.850±0.885), (24.613±0.640), (27.013±0.734)/s (F=89.323, P<0.01) showed different trends with time in the treatment group, and the differences were statistically significant. The K(trans) values and tumor vessel maturity index (VMI) were higher than baseline values during 3-12 d after treatment. CD31 positive staining rate and VMI had the strongest correlations with K(trans) values (r=0.854 and 0.795), followed by AUC(180) (r=0.750 and 0.808), Ve (r=0.744 and 0.712) and K(ep) values (r=0.729 and 0.758), all P<0.05. R2* value positively correlated with the positive staining rate of HIF-1α and fibronectin (r=0.810 and 0.816), all P<0.05. Conclusion: DCE-MRI and BOLD-MRI are adequate to observe the tumor perfusion and hypoxia during anti-vascular treatment, and the R2* value can predict the tumor metastatic potential during the process of vascular normalization.

[Application of complete endoscopic technique in microvascular decompression related tovertebrobasilar artery compression]

Objective: To study the operative method, special technique and curative effect of complete neuroendoscopic microvascular decompression(MVD) related to vertebrobasilar artery compression. Methods: Thirteen patients with functional cranial nerve disease caused by vertebrobasilar artery as direct or indirect responsible vessel accepted complete endoscopic MVD, including 11 patients with hemifacial spasm and 2 patients with trigeminal neuralgia. The procedure and curative effect of endoscopic surgery were analyzed retrospectively. Results: All procedures of complete neuroendoscopic MVD were successfully completed.Intraoperative observation by endoscope showed that 6 cases were oppressed directly by vertebral artery, 2 cases were oppressed directly by basilar artery, 5 cases were combined oppressed by displaced basilar artery and other vessels (1 case was superior cerebellar artery and 4 cases were anterior inferior cerebellar artery). During the operation, Teflon sheets was placed directly into the compression point in 2 cases, the "Pre-placed" technique was used to place Teflon sheets in 7 cases, and the "Set up bridge" technique was used to place Teflon sheets in 4 cases. Follow-up for 8-38 months,the symptoms disappeared completely in 12 cases and improved in 1 case. No deaths and severe complications occurred, such as postoperative bleeding, cerebellar infarction and intracranial infection. Conclusion: MVD related to vertebrobasilar artery compression can be performed by complete neuroendoscopic technique, which can achieve sufficient decompression effect and curative effect.Flexible use of the special technology of placing Teflon sheets by single-hand under endoscope, such as the "Pre-placed" and "Set up bridge" technique, is an important technical guarantee for the successful completion of endoscopic MVD.

[Efficacy analysis of soft neuroendoscopic techniques in the treatment of chronic subdural hematoma]

Objective: To investigate the efficacy of soft neuroendoscopic techniques in the treatment of chronic subdural hematoma (CSDH). Methods: A retrospective analysis of 201 cases of CSDH diagnosed and treated at Beijing Shijitan Hospital (CMU) from January 2006 to December 2017 was conducted. From January 2006 to December 2010, 126 cases of CSDH were treated with skull drilling and drainage (non-endoscopic group). From January 2011 to December 2017, 75 cases of CSDH were treated with soft neuroendoscopy (endoscopic group). The operation time of the non-endoscopic and endoscopic groups, the hematoma clearance rate on the first day after surgery, the time of the drainage tube, the length of hospital stay, the incidence of complications, mortality and recurrence rate were compared. Results: There were no deaths in both groups. The average operation time of the non-endoscopic group was 43 min, compared with the average operation time of the endoscopy group of 50 min, there was no significant difference (P>0.05). The average hematoma clearance rate on the first day after surgery in the endoscopy group (98.2%) was significantly higher than that in non-endoscopic group (87.3%) (P<0.01). The average time of drainage tube in the endoscopy group (23 h) was significantly shorter than that in the non-endoscopic group (50 h) (P<0.01). On the first postoperative day, the proportion of patients with mRS≤3 in the endoscopic group was significantly higher than that in the non-endoscopic group (P<0.01). At the time of discharge, the proportion of patients with mRS≤3 in the endoscopy group was also significantly higher than that in the non-endoscopic group, P<0.05. There was no significant difference in the average hospital stay between endoscopy group (7 d) and non-endoscopic group (8 d) (P>0.05). The postoperative complication rate in the endoscopy group was significantly lower than that in the non-endoscopic group (P<0.01). During 0.5-8 years of follow-up, the recurrence rate of CSDH in the endoscopic group (5.33%) was significantly lower than that in the non-endoscopic group (15.07%) (P<0.01). Conclusion: The application of visualization features of soft neuroendoscopy in the treatment of CSDH can significantly improve hematoma clearance, shorten the time of drainage tube, reduce postoperative complications and recurrence rate, and improve surgical outcomes.

[Value of bedside echocardiography in diagnosis and risk assessment of in-hospital death for patients with Stanford type A aortic dissection]

Objective: To investigate the value of bedside echocardiography in diagnosis and risk assessment of in-hospital death of patients with Stanford type A aortic dissection. Methods: The clinical data of 229 patients with Stanford type A aortic dissection diagnosed by CT angiography in Zhongshan Hospital affiliated to Fudan University between January 2009 and January 2016 were retrospectively analyzed. The patients were divided into survival group(191 cases)and non-survival group(38 cases)according to presence or absence of in-hospital death. The bedside echocardiography features were analyzed, and influence factors of in-hospital death were determined by multivariate logistic regression analysis. Results: (1) Compared with the survival group, the non-survival group had lower surgery rate (60.52%(23/38) vs. 85.34%(163/191), P<0.01). Age, gender and Debakey classification were similar between survival group and death group (all P>0.05). (2) The bedside echocardiography results showed that prevalence of aortic valve involvement(65.79%(25/38) vs.34.03%(65/191), P<0.01) and severe aortic regurgitation (44.74%(17/38) vs. 14.14%(27/191), P<0.01) were significantly higher in non-survival group than in survival group. The non-survival group had larger aortic root diameter than the survival group ((55.5±6.4)mm vs. (42.3±7.8)mm, P<0.01). There were no significant differences in pericardial effusion, expansion of aortic sinus, and left ventricular ejection fraction between survival group and non-survival group (all P>0.05). (3) The multivariate logistic regression analysis showed that aortic valve involvement(OR=3.275, 95%CI 1.290-8.313, P<0.05), aortic root diameter(OR=1.202, 95%CI 1.134-1.275, P<0.01), and surgery (OR=0.224, 95%CI 0.079-0.629, P<0.01) were independent risk factors for in-hospital death in patients with Stanford type A aortic dissection. Conclusions: Bedside echocardiography has significant diagnostic value for Stanford type A aortic dissection. Aortic valve involvement, enlargement of aortic root diameter and without surgery are independent risk factors for patients with Stanford type A aortic dissection.

[Relationship between multi-slice spiral CT angiography imaging features and in-hospital death of patients with aortic dissection]

Objective: To explore the imaging manifestations of multi-slice spiral CT angiography (CTA) and relationship with in-hospital death in patients with aortic dissection (AD). Methods: The clinical data of 429 patients with AD who underwent CTA in Zhongshan Hospital of Fudan University between January 2009 and January 2016 were retrospectively analyzed. AD patients were divided into 2 groups, including operation group who underwent surgery or interventional therapy (370 cases) and non-operation group who underwent medical conservative treatment(59 cases). The multi-slice spiral CTA imaging features of AD were analyzed, and multivariate logistic regression analysis was used to investigate the relationship between imaging manifestations and in-hospital death in AD patients. Results: There were 12 cases (3.24%) of in-hospital death in operation group, and 28 cases (47.46%) of in-hospital death in non-operation group(P<0.001). AD involved different vascular branches. Multi-slice spiral CTA can clearly show the dissection of true and false lumen, and intimal tear was detected in 363 (84.62%) cases, outer wall calcification was revealed in 63 (14.69%) cases, and thrombus formation was present in 227 (52.91%) cases. The multivariate logistic regression analysis showed that the number of branch vessels involved (OR=1.374, 95%CI 1.081-1.745, P=0.009) and tearing false lumen range(OR=2.059, 95%CI 1.252-3.385, P=0.004) were independent risk factors of in-hospital death in AD patients, and the number of branch vessels involved (OR=1.600, 95%CI 1.062-2.411, P=0.025) was independent risk factor of in-hospital death in the operation group, while the tearing false lumen range (OR=2.315, 95%CI 1.019-5.262, P=0.045) was independent risk factor of in-hospital death of non-operation group. Conclusions: Multi-slice spiral CTA can clearly show the entire AD, true and false lumen, intimal tear, wall calcification and thrombosis of AD patients. The number of branch vessels involved and tearing false lumen range are the independent risk factors of in-hospital death in AD patients.

[The application value of two-dimensional image technology and three-dimensional visualization technology in hepatocellular carcinoma treated by associating liver partition and portal vein ligation for staged hepatectomy: a preliminary study]

OBJECTIVE

To preliminarily explore the application value of two-dimensional image technology and three-dimensional visualization technology in hepatocellular carcinoma(HCC) treated by associating liver partition and portal vein ligation for staged hepatectomy(ALPPS).

METHODS

Clinical data of nineteen HCC patients treated by ALPPS were retrospectively analyzed in Sun-Yat-Sen Memorial Hospital of Sun Yat-Sen University from August 2013 to May 2015.Preoperative assessment, surgical planning and intraoperative guidance were assisted by traditional two-dimensional imaging technology(group 2D) in 15 cases, and the rest 4 cases were assisted by three-dimensional visualization technology(group 3D).

RESULTS

Three-dimensional visualization technology offered precise, visual, and distinct images, calculated the liver volume precisely, achieved virtual simulation operations, and assisted the formulation of intraoperative decisions.The mean operation time of the first stage were(331.3±61.7)minutes and (261.3±21.4)minutes in group 2D and group 3D, and the mean volume of intraoperative bleedings were (360.7±51.9)ml and (300.0±40.8)ml, respectively.The mean operation time of the second stage were (199.3±41.0)minutes and (170.0±29.4)minutes in group 2D and group 3D, and the mean volume of intraoperative bleedings were (285.3±132.6)ml and (257.5±99.5)ml, respectively.The mean interval time between two stages of operations were (15.3±6.5)d and (13.8±5.1)d in group 2D and group 3D, and the mean hospital stays were (39.3±5.8)d and (31.5±7.5)d, respectively.There were 4 cases and 12 cases who accepted the second stage operation in group 2D and group 3D respectively.There were 7 cases(4 with grade A, 2 with grade B, 1 with grade C) and 2 cases(1 with grade A, 1 with grade B) with post-hepatectomy liver failure and 9 cases(4 with grade Ⅰ, 2 with grade Ⅱ, 1 with grade Ⅲ, 2 with grade Ⅳ) and 3 cases (1 with grade Ⅰ, 1 with grade Ⅱ, 1 with grade Ⅲ)with postoperative complications in group 2D and group 3D respectively.There were 2 cases and 0 case died after operation in group 2D and group 3D respectively.There were 3 cases and 1 case who were recurrent and 4 cases and 1 case died 6 months after surgery in group 2D and group 3D respectively.

CONCLUSION

Three-dimensional visualization technology assisted the formulation of preoperative assessments and surgical planning individually and precisely, which displayed potential application value in HCC treated by ALPPS.

Fabrication and biological characteristics of beta-tricalcium phosphate porous ceramic scaffolds reinforced with calcium phosphate glass

The fabrication process, compressive strength and biocompatibility of porous beta-tricalcium phosphate (beta-TCP) ceramic scaffolds reinforced with 45P(2)O(5)-22CaO-25Na(2)O-8MgO bioglass (beta-TCP/BG) were investigated for their suitability as bone engineering materials. Porous beta-TCP/BG scaffolds with macropore sizes of 200-500 muicrom were prepared by coating porous polyurethane template with beta-TCP/BG slurry. The beta-TCP/BG scaffolds showed interconnected porous structures and exhibited enhanced mechanical properties to those pure beta-TCP scaffolds. In order to assess the effects of chemical composition of this bioglass on the behavior of osteoblasts cultured in vitro, porous scaffolds were immersed in simulated body fluid (SBF) for 2 weeks, and original specimens (without soaked in SBF) seeded with MC3T3-E1 were cultured for the same period. The ability of inducing apatite crystals in simulated body fluid and the attachment of osteoblasts were examined. Results suggest that apatite agglomerates are formed on the surface of the beta-TCP/BG scaffolds and its Ca/P molar ratio is approximately 1.42. Controlling the crystallization from the beta-TCP/BG matrix could influence the releasing speed of inorganic ions and further adjust the microenvironment of the solution around the beta-TCP/BG, which could improve the interaction between osteoblasts and the scaffolds.

Preparation of ZnO colloids by aggregation of the nanocrystal subunits

Colloidal ZnO particles with narrow size distribution were prepared via a sol-gel process by base-catalyzed hydrolysis of zinc acetate. The morphology of ordered arrays of the particles was recorded by SEM. SEM also reveals that these uniform particles were composed of tiny ZnO subunits (singlets) sized of several nanometers. The size of the singlets, which is confirmed by X-ray diffraction and UV-vis absorption spectra, increases as the aging time is prolonged. The size-selective formation of colloids by aggregation of nanosized subunits is proposed to consist of two-stage growth by nucleation of nanosized crystalline primary particles and their subsequent aggregation into polycrystalline secondary colloids. The aggregates are all spherical because the internal rearrangement processes are fast enough. The ZnO colloids, i.e., the aggregates, tend to self-assemble into well-ordered hexagonal close-packed structures. Room-temperature photoluminescence was characterized for green and aged ZnO.

The effect of surface properties on visible luminescence of nanosized colloidal ZnO membranes

Luminescence properties of nanosized zinc oxide (ZnO) colloids depend greatly on their surface properties, which are in turn largely determined by the method of preparation. ZnO nanoparticles in the size range from 3 to 9 nm were prepared by addition of tetramethylammonium hydroxide ((CH3)4NOH) to an ethanolic zinc acetate solution. X-ray diffraction (XRD) indicates nanocrystalline ZnO membranes with polycrystalline hexagonal wurtzite structure. The ZnO membranes have a strong visible-emission intensity and the intensity depends upon hydrolysis time. The infrared spectra imply a variety of forms of zinc acetate complexes present on the surface of ZnO particles. The effect of the ZnO membrane surface properties on photoluminescence is discussed.

[Seronegative synovitis syndrome]

3 cases of seronegative synovitis syndrome were reported. Two elderly women and one man presented with symmetrical polysynovitis of acute onset involving most of their appendicular joints and flexor digitorum tendons associated with pitting edema of the dorsum of both hands and both feet. Rheumatoid factor was absent from serum samples in all and no radiologically evident erosions developed. All the three patients had a benign course and the disease resolved completely within 2-18 months after the onset. None had deformities, erosions and/or relapse after being followed for 22-34 months. Literatures on this syndrome were reviewed.

[Chemical constituents of Drynaria propinqua (Wall) J. Sm]

Four compounds isolated from the rhizomes of Drynaria propinqua collected in Sichuan have been identified. One of them was a new natural product, namely propinqualin, whose structure was established as (-)-epiafzelechin-3-O-beta-D-allopyranoside. The other three were 4-O-beta-D-glucopyranosyl caffeic acid, beta-sitosterol-3-O-beta-D-glucopyranoside and sucrose.

[Anti-arrhythmic effects and electrophysiological properties of Ophiopogon total saponins]

The arrhythmias induced by chloroform-epinephine, BaCl2, and aconitine were prevented and antagonized by Ophiopogon total saponins (OTS) which were extracted from the root of Ophiopogon japonicus (Thunb) Ker-Gawl. The incidence of ventricular arrhythmia produced by ligation of the left anterior descending coronary artery was effectively decreased without any changes in the hemodynamic indices of dogs. The electrophysiological effects of OTS in vivo and in vitro were studied by means of contact electrode and intracellular microelectrode techniques. The results showed that OTS shortened APD10, APD50, APD90; decreased APA and Vmax of both monophasic and transmembrane action potentials. OTS also increased the ERP/APD ratio and prevented or abolished the arrhythmikinesis provoked by ouabain and aconitine. The anti-arrhythmic properties of OTS lead us to draw an inference that the anti-arrhythmic mechanism may be related to the blocking of sodium and calcium channels.

Rapid separation of flavonoids by analytical high-speed counter-current chromatography

A commercial model of the analytical high-speed counter-current chromatography instrument was used for separation of flavonoids from a crude ethanol extract of dried fruits of sea buckthorn (Hippophae rhamnoides). Using a two-phase solvent system of chloroform-methanol-water (4:3:2), a five-fold increase in flow-rate of the mobile phase from 60 to 300 ml/h resulted in a rapid separation of five components in less than 15 min without significant loss in peak resolution. Major flavonoid component, isorhamnetin, was identified in its pure state by mass spectrometric analysis.

Multistage evaluation scale, differential threshold steps and equivalent sensation contours of respiratory flow-resistive load sensation

This paper presents and discusses the methodology and results of studies on respiratory sensation by using a fuzzy set category judgement model and applying the concept of just noticeable difference (JND) step and equivalent sensation. A new kind of category scale, the multistage evaluation scale (MES), based on a fuzzy set category judgement model for quantifying respiratory sensory magnitude has been put forward and verified in 37 subjects. The perceived magnitude of added resistance estimated using MES could reflect properly the difference in sensory perception caused by added loads with equal intensity but applied to different phases of the breathing cycle. In addition, the psychophysical function obtained conforms to the Stevens' power law. On the contrary, the classical category scale does not possess some of these attributes. In 9 subjects, we determined that the sensory continuum corresponding to either inspiratory or expiratory added resistive load, ranging 10-500 mm H2O.1(-1).s, consisted of 6 or 7 JND steps. The sensory magnitude corresponding to each step was estimated by the MES. Relating the results of JND step measurements with that of magnitude estimation using MES, we could elucidate systematically the relationship between perceived magnitude and discrimination for respiratory sensation. In 13 subjects, the equivalent respiratory resistive load sensation contours of 2, 3 and 4 JND step above basal level, respectively, were obtained through experimentation and by quadratic polynomial approximation of experimental data. The results suggest that as regards the human tolerance to various added resistive loads the combined resistive load is the most tolerable among the three; the expiratory, the least. The equivalent sensation contour can be used to predict the changes in respiratory sensation determined by both the intensity of the total added load and the ratio of inspiratory versus expiratory load. In brief, we have proposed a new way to elucidate the physiological and psychophysical effects of various added resistive loads.