Lymphocyte Count Kinetics and the Effect of Different Radiotherapy Techniques on Radiation-Induced Lymphopenia in Patients with Breast Cancer Receiving Hypofractionated Postmastectomy Radiotherapy

PURPOSE/OBJECTIVE(S)

Radiation-induced lymphopenia (RIL) is associated with poor prognosis in solid tumors. This study aimed to describe the lymphocyte kinetics in patients with breast cancer receiving hypofractionated postmastectomy radiotherapy (RT) and to investigate the association of different RT techniques with RIL.

MATERIALS/METHODS

We assessed 607 patients who received hypofractionated postmastectomy RT for breast cancer in our prospective clinical database from 8 hospitals. All patients received irradiation to the chest wall and supraclavicular fossa. RT techniques included integrated RT with the photon-based intensity modulated techniques to irradiate all target volumes (integrated RT) and a hybrid approach combining photon irradiation to supraclavicular nodes and electron irradiation to the chest wall (hybrid RT). Peripheral lymphocyte counts (PLC) were tested prior to RT (baseline), weekly during RT, at 1, 2 weeks, 3, 6 months after RT, and then every 6 months. Grade 3+ RIL was defined as PLC nadir during RT of <0.5 ×103/ml. Mean PLC was compared by the t test. Univariate, multivariate, and propensity score matching (PSM) analyses were used to evaluate the effect of different RT techniques on grade 3+ RIL.

RESULTS

During RT, 121 (19.9%) of patients had grade 3+ RIL. The PLC started to recover at 1 week and reached baseline levels 1 year after RT. A greater proportion of the patients treated with the integrated RT (90/269, 33.5%) developed grade 3+ PLC compared with those receiving hybrid RT (31/338, 9.2%, P < 0.001). After conducting PSM, multivariate analyses showed lower baseline PLC (HR = 0.15, P<0.001) and RT technique (the integrated RT vs. hybrid RT, HR = 4.76, P<0.001) were independent risk factors for grade 3+ RIL. The PLC in patients receiving the integrated RT after RT were higher than that in those receiving hybrid RT (p<0.05).

CONCLUSION

RT technique affect the risk of and recovery from RIL, which may impact survival. Choosing appropriate RT technique to minimize RIL might be considered to benefit their outcomes.

Dose-Volume Predictors for Radiation Esophagitis in Breast Cancer Patients Undergoing Hypofractionated Regional Nodal Radiotherapy

PURPOSE/OBJECTIVE(S)

Radiation esophagitis (RE) is often overlooked in breast cancer radiotherapy. This study aimed to assess the incidence and dose-volume predictors of RE in breast cancer patients undergoing hypofractionated regional nodal irradiation (RNI).

MATERIALS/METHODS

Eligible patients were included who received intensity-modulated radiotherapy (RT) at the chest wall, the supraclavicular/infraclavicular fossa, level II axilla, and/or the internal mammary chain after mastectomy. The prescribed dose was 43.5 Gy in 15 fractions. The dose constraint for the esophagus was maximum dose <48 Gy. RE was evaluated weekly during RT and at 1 and 2 weeks, followed by 3 and 6 months after RT, and was graded according to the Common Toxicity Criteria for Adverse Events v3.0. The esophagus was contoured from the lower border level of the cricoid cartilage to the lower margin of the aortic arch. Esophageal total volume, mean dose (Dmean), maximum dose (Dmax), and the relative and absolute volumes receiving at least 5-45 Gy by 5 Gy increments (RV5-RV45 and AV5-AV45) were evaluated. Univariable and multivariable logistics regression analyses were performed to determine risk factors for RE, and receiver operating characteristic curves were obtained to identify the thresholds of esophageal dosimetric parameters.

RESULTS

In total, 298 patients were included between May 8, 2020 and January 5, 2022 (minimum post-RT follow-up: 6 months). A total of 153 (51.3%) patients had left-sided breast cancer and 145 (48.7%) patients received internal mammary nodal irradiation (IMNI). Grade 2 and 3 RE incidence was 40.9% (122/298) and 0.3% (1/298), respectively. No grade 4 or 5 RE was observed. All RE cases resolved within 1 month after RT, and the median duration of RE was 3 weeks (range, 1-5). Based on univariable analyses, tumor laterality (p < .001), IMNI (p = .056) and esophageal Dmean, Dmax, RV10-RV40, and AV10-AV40 were risk factors of ≥grade 2 RE. Esophageal RV10-RV40 and AV35-AV40 were significantly associated with the risk of ≥grade 2 RE after adjusting for tumor laterality and IMNI. Based on multivariable analyses, RV25 and AV35 were optimum dose-volume predictors for ≥grade 2 RE at thresholds 20% for RV25 (35.9% vs. 60.9%, p = .04) and 0.27 mL for AV35 (31.0% vs. 54.6%, p = .04).

CONCLUSION

RE is common in breast cancer patients undergoing hypofractionated RNI. With the same esophageal contouring standard, maintaining the upper esophageal V25 at <20% and V35 at <0.27 mL may decrease the risk of RE and improve the quality of life of patients.

Quality Assurance in a Phase III, Multicenter, Randomized Trial of POstmastectomy radioThErapy in Node posiTive Breast Cancer with or without Internal mAmmary nodaL Irradiation (POTENTIAL): A Planning Dummy Run

PURPOSE/OBJECTIVE(S)

To report the planning dummy run results of the POstmastectomy radioThErapy in Node posiTive breast cancer with or without Internal mAmmary nodaL irradiation (POTENTIAL) trial-a multicenter, randomized, phase 3 trial-to evaluate postmastectomy radiotherapy, with or without internal mammary nodal irradiation, for patients with high-risk breast cancer.

MATERIALS/METHODS

All participating institutions were provided the contours of the dummy run case, and they generated radiotherapy (RT) plans per protocol guidelines. The plans were reviewed and feedback were provided by the quality assurance team, after which the institutions resubmitted revised plans. The information on beams arrangement, skin flash, inhomogeneity corrections, and protocol compliance was assessed both in the primary and final submission.

RESULTS

Theplans from 26 institutions were included in the analysis. A number of major deviations were found in the primary submission, such as less strict constraint on organs at risk (OARs) V5Gy, and no application of chest wall skin flash. The protocol compliance rates of the dose coverage for the planning target volume of the chest wall (PTVcw), PTV of supra/infraclavicular fossa plus axilla levels I, II, III (PTVsc+ax), and PTV of the IMN region (PTVim) were all significantly improved in the final submission compared with those in the primary submission, which were 96.2% vs. 69.2%, 100% vs. 76.9%, and 88.4% vs. 53.8, respectively. For OARs, the protocol compliance rates of heart Dmean, left anterior descending coronary artery V40Gy, ipsilateral lung V5Gy, and stomach V5Gy were significantly improved.

CONCLUSION

All major deviations were corrected and protocol compliance was significantly improved and of high level in the final submission. Moreover, the variations were reduced. Therefore, a planning dummy run was essential to guarantee good RT plan quality and inter-institutional consistency for multicenter trials.

[Clinical and electrophysiological features and treatment of acrylamide-induced toxic peripheral neuropathy]

Objective: To investigate the clinical manifestations, electrophysiology results, treatment and prognosis of acrylamide-induced toxic peripheral neuropathy. Methods: The clinical data of 9 patients with acrylamide-induced toxic peripheral neuropathy, who were collected in Jinhua Municipal Central Hospital from January 2015 to August 2018, were retrospectively reviewed. Results: This disease was characterized by distal limb numbness, some patients with hypoalgesia or allergy, deep sense loss, reduction or disappearance of tendon reflexes, and peeling. One case had muscle weakening and another case had cerebellar ataxia. Examination of electromyography showed only one case had spontaneous potential. Examination of nerve conduction showed that the amplitude decreased by 34 (38.6%) and the velocity decreased by 2 (2.3%) , the percentage of amplitude decreased was significantly higher than that of velocity decreased. The amplitude of sensory nerve decreased by 30 (57.7%) and motor nerve decreased by 4 (11.1%) , the percentage of sensory nerve amplitude decreased was significantly higher than that of motor nerve. After the treatment of nutrition, circulation improvement, numbness relief, glucocorticoid and other drugs, the numbness of the patients was relieved, but it did not completely disappear. Poor recovery of pain, deep sensation and tendon reflex in all patients. The results of reexamination of electromyography in 3 cases were worse than before. Therefore, it is suggested that peripheral nerve damage is irreversible. Conclusion: This disease is characterized by distal limb numbness. Electrophysiological results suggest that the damage of sensory nerve axon is the main cause of the disease. Up to now, there is no effective drug to treat this disease, therefore, it is very important to do a good job of protection.

[Correlation of capillary plexus with visual acuity in idiopathic macular epiretinal membrane eyes using optical coherence tomography angiography]

Objective: To observe changes in foveal avascular zone(FAZ) and capillary plexus in idiopathic macular epiretinal membrane (IMEM) in optical coherence tomography angiography (OCTA) and analyze their correlation with the visual acuity. Methods: Cross-sectional study. 42 patients (15 Males and 27 females, age 64.8) from the Eye Hospital of Wenzhou Medical University were included with 51 eyes diagnosed as IMEM (IMEM group), and 23 normal eyes (9 Males and 14 females, control group). All patients received the examination of fissure lamp combined with fundus pre-set lens, best corrected visual acuity (BCVA), OCT angiography (OCTA) and fundus photo. OCTA was performed on 3 mm× 3 mm sections centred on the fovea. The software automatically measured the superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density(VD) and retinal thickness(RT) and FAZ area. The IMEM eyes were compared with the normal eyes and correlation between the parameters of OCTA and BCVA was analyzed in IMEM. Independent-sample t test and MannWhitney test were used for comparison between groups, and Spearman test was used for correlation analysis. Results: LogMAR BCVA in the IMEM group was 0.40(0.15, 0.70), in the control group was 0.10(0.05, 0.22). FAZ area of IMEM group was (0.09±0.05) mm(2), while that of control group was (0.34±0.13)mm(2).Compared with the control group, in IMEM group, the BCVA was worse (Z=-4.443, P<0.001), FAZ area was smaller (t=-9.198, P<0.001), RT was increased (P<0.001), The foveal DCP and SCP vessel density was increased (t=4.280, 9.079, P<0.01), The parafoveal DCP vessel density was decreased (P<0.05), The parafoveal SCP vessel density was decreased in superior, inferior and nasal side (t=-2.759, Z=-3.998, Z=-2.108; P<0.05). The BCVA was negatively correlated with FAZ area (r=-0.337, P=0.017), positively correlated with center macular thickness (r=0.324, P=0.020). The BCVA was no correlated with foveal VD and parafoveal DCP vessel density (P>0.05), but correlated with SCP vessel density(P<0.05). Conclusions: In the IMEM eyes the BCVA was worse, FAZ area was smaller, foveal vessel density was increased and the parafoveal vessel density was decreased compared with the normal eyes. The smaller the FAZ area, the smaller foveal SCP vessel density, the poorer BCVA. There was no correlation between BCVA and DCP vessel density. Changes in VD in IMEM eyes may lead to changes in vision. (Chin J Ophthalmol, 2019, 55:757-762).

Study on the preparation of granular alum sludge adsorbent for phosphorus removal

Alum sludge is the sludge discharged from a sedimentation tank in a drinking water treatment plant when polymerized with poly-aluminum chloride (PAC). In this paper, granular alum sludge adsorbent (GASA) was manufactured using powdery alum sludge (PAS) as the raw material and methods such as gluing and pore-forming. The effects of different binders, pore-forming agents, roasting temperatures, and roasting times on the formation of GASA and its dephosphorization performance were investigated. Results showed that the optimum binder was AlCl₃ at a mass ratio of 8%, and the best pore-forming agent was starch at a 4% dosage ratio. Meanwhile, the optimum roasting temperature and time were 500 °C and 2 hours, respectively. The specific surface area of GASA was 23.124 m²/g. Scanning electron microscopy suggested that GASA's surface became rough, particles became tight, and average pore size increased, with additional pore channels. P adsorption by GASA reached 0.90 mg/g. The effluent phosphorus concentration of actual tail water decreased to 0.49 mg/L and the removal rate reached 73.5% when the GASA dosage was 20 g/L. The findings of this study are important for the further development of a low-cost adsorbent material for P removal in the future.

Biodegradation of polyvinyl alcohol by different dominant degrading bacterial strains in a baffled anaerobic bioreactor

Polyvinyl alcohol (PVA) is the main pollutant in printing and dyeing wastewaters. This pollutant exhibits great demand, poor biodegradability and refractory degradation. In this study, PVA wastewater treatment experiments were conducted in a stably operating baffled anaerobic bioreactor (ABR) by using simulated PVA wastewater. The PVA degradation pathway and mechanism of the mixed dominant PVA-degrading bacterial strains were identified through the analysis of their degradation products. From the results, we inferred that PVA was degraded in a stepwise process under the synergistic action of different extracellular and intracellular enzymes produced by the mixed dominant PVA-degrading bacterial strains. In this process, PVA was first degraded into ketones, fatty acids and alcohols. It was then regenerated into acetic acid, hydrogen and carbon dioxide. Finally, these substances could be further utilized by methanogens. PVA was thus degraded completely. This study may serve as a reference for future works on the degradation of PVA in the ecological environment. It may also guide the sustainable development of PVA.

[Risk factors of retinopathy of prematurity in extremely low birth weight infants by strictly controlling oxygen inhalation after birth]

Objective: To observe the incidence and severity of retinopathy of prematurity (ROP) in extremely low birth weight (ELBW) infants by strictly controlling the risk factors of ROP, such as oxygen inhalation after birth, to explore the related factors of ROP in ELBW infants. Methods: This was a cross-sectional study. 166 ELBW infants underwent neonatal screening were enrolled in this study, whose birth weight was less than 1 000 g. There were 79 males and 87 females infants, whose average gestational age was (27.99±1.73)weeks, and average birth weight was (904.45±80.23)g. According to the final screening results, the ELBW infants were grouped as follows: (1)ROP group and non-ROP group; (2)severe ROP group and mild or no ROP group. Risk factors included gestational age, birth weight, test-tube infants, fetuses number, complications during pregnancy, delivery mode and Apgar scores in 1 to 10 minutes, weight and weight gain proportion at 1-6 weeks after birth, postnatal feeding mode, history of oxygen inhalation, anemia and blood transfusion, and other systemic diseases were recorded. And their correlation with severe ROP was analyzed by SPSS 20.0 statistical software. Results: Ninty-four (56.63%) ELBW infants developed ROP, 16 (9.64%) were severe ROP and 14(8.43%) received treatment. Average birth weight between ROP group (911.95±72.80)g and non-ROP group (894.67±88.58)g had no difference(t=1.379, P=0.170). Average gestational age between ROP group (27.49±1.53) weeks and non-ROP group (28.64±1.76) weeks had significant difference(t=-4.491,P<0.001).And pregnancy-induced hypertension during pregnancy (χ(2)=4.479, P=0.034), Apgar score in 5 minutes (t=-2.760, P=0.006) and 10 minutes (t=-2.099, P=0.043), pneumonia (χ(2)=6.233, P=0.013), neonatal pneumonia (χ(2)=18.026, P<0.001) had significant difference between ROP group and non-ROP group. There was no effect on weight (F=0.009,P=0.753) or weight gain proportion (F=2.394,P=0.124) at 1-6 weeks after birth in ELBW infants with or without ROP. Average birth weight between severe ROP group(875.63±74.85)g and mild or no ROP group(907.53±80.41)g had no difference(t=-1.518, P=0.131).Average gestational age between severe ROP group(26.88±1.31)weeks and mild or no ROP group (28.11±1.73)weeks had significant difference(t=-2.766,P=0.006).And only fundus hemorrhage (χ(2)=4.507,P=0.034) had significant difference between severe ROP group and mild or no ROP group. There was no effect on weight (F=2.683,P=0.103) or weight gain proportion (F=0.431,P=0.513) at 1-6 weeks after birth in ELBW infants with or without ROP. Logistic regression analysis revealed that only gestational age was correlated to the incidence (β=-0.437,P<0.001) and severity (β=-0.616,P=0.007) of ROP significantly. Conclusion: By strictly controlling the risk factors of ROP, such as oxygen inhalation after birth, the severe rate of ROP in ELBW infants is low. However, gestational age is still the inevitable independent high risk factor for the incidence of ROP in ELBW infants. (Chin J Ophthalmol, 2019, 55:280-288).

Prediction of the livestock carrying capacity using neural network in the meadow steppe

In order to predict the livestock carrying capacity in meadow steppe, a method using back propagation neural network is proposed based on the meteorological data and the remote-sensing data of Normalised Difference Vegetation Index. In the proposed method, back propagation neural network was first utilised to build a behavioural model to forecast precipitation during the grass-growing season (June–July–August) from 1961 to 2015. Second, the relationship between precipitation and Normalised Difference Vegetation Index during the grass-growing season from 2000 to 2015 was modelled with the help of back propagation neural network. The prediction results demonstrate that the proposed back propagation neural network-based model is effective in the forecast of precipitation and Normalised Difference Vegetation Index. Thus, an accurate prediction of livestock carrying capacity is achieved based on the proposed back propagation neural network-based model. In short, this work can be used to improve the utilisation of grassland and prevent the occurrence of vegetation degradation by overgrazing in drought years for arid and semiarid grasslands.

[Clinical analysis for preset double J tube in percutaneous nephrolithotripsy]

Objective: To evaluate the clinical application and effect of preseting Double-J ureteric stent in percutaneous nephrolithotripsy. Method: 74 cases of renal calculi treated with PCNL in our hospital during June 2014 to February 2017 were retrospectively analyzed. Of 74 cases, 54 was male, 20 was female. All cases were aged 27 to 78, the mean age was (49.5±12.3) years old. The diameter of the stone was 20 to 59 mm, and the mean diameter was of (29.4±4.3) mm.Our Surgical methods was first putingFr6 double J tube in abnormal ureteral in advance in lithotomy position, then indwellingthree-way Foley catheter and clipping drainage port, perfusingirrigation port with 3 000 ml saline from 60-80 cm height.Perfusingsaline through irrigation port in prone position, we produce artificial hydronephrosis, then indwelling channel Fr20 through B ultrasound guided percutaneous nephrostomy, and removing renal calculi using holmium laser lithotripsy. Results: All patients were successfully completed percutaneous nephrostomy and indwell Fr20 channel, mean channel set up time (8.0 ±2.0) min, mean operation time (79±46) min, mean decline of hemoglobin (17.0±4.0) g/L, mean serum creatinine increased(3.1±1.1) μmol/L, one-stage stone-free rates 81.1%, complication rate 8.1% (1 case injured pleura and suffered from pneumothorax, 1 case suffered from massive hemorrhage of renal arteriovenous fistula after operation, 4 cases suffered postoperative fever). Conclusion: Advance in percutaneous nephrolithotripsy indwelling double J tube is a safe and feasible method, which is advantageous to the percutaneous renal puncture and the establishment of channels, and can avoid the blindness of along the line of indwelling double J.

Characterization of tissue chromogranin A (CgA) immunostaining and clinicohistopathological changes for the 125 Chinese patients with primary small cell carcinoma of the esophagus

The rarity of primary small cell carcinoma of the esophagus (PSCE) has limited the clinical feature and survival analysis with large sample size. Tissue chromogranin A (CgA) protein expression has been reported to be a useful biomarker for diagnosing PSCE. Interestingly, recent studies have indicated tissue CgA as a significant prognostic marker in multiple human cancers, but without PSCE. The present study, thus, was undertaken to characterize the clinicopathological changes and to evaluate the associations of tissue CgA expression with clinical response on Chinese PSCE patients. All the 125 PSCE patients were enrolled from our 500,000 esophageal and gastric cardia carcinoma databases (1973-2015), constructed by the cooperative team from more than 700 hospitals in China and established by Henan Key Laboratory for Esophageal Cancer Research in Henan, China. Immunostaining for CgA showed that CgA was mainly located in cytoplasm of tumor cells with a positive detection rate of 44.6%. The CgA positive expression rate in PSCE at lower segment of the esophagus (72.2%) was higher than that at middle segment (41.5%) (P = 0.001). However, CgA protein expression did not correlated with lymph node metastasis (P = 0.767), TNM staging (P = 0.740), tumor invasion (P = 0.253), gender (P = 0.262), and age (P = 0.250). Multivariate survival analysis showed that the patients with higher CgA protein expression had a superior long survival than those without CgA expression (P = 0.037). The clinicopathological analysis showed that PSCE occurred predominantly in male (M:F = 1.9:1) at the middle segment (68%) of the esophagus. Histologically, 89.6% were pure PSCE and 10.4% were mixed type with either squamous cell carcinoma (8%) or adenocarcinoma (2.4%). It was noteworthy that, with the in-depth invasion from T1 to T2 and T3, the positive lymph node metastasis rate increased dramatically from 38%, 56% to 74%, respectively. The survival rates of 1-, 2-, 3-, and 5-year were 64%, 35%, 18%, and 7%, respectively. The Kaplan-Meier survival analysis showed that the young patients (≤60 years) had longer survival than the elderly (P = 0.011). Interestingly, multivariate survival analysis revealed that the patients with mixed PSCE had a significantly better survival than those with pure PSCE (P = 0.015). Furthermore, the median survival time for the patients with and without lymph node metastasis was 1.16 and 2.03 years, respectively. But, the difference was not significant (P = 0.143). Univariate analysis did not show any survival influence by gender, tumor location, tumor invasion depth, and TNM staging. It was noteworthy that, of the 13 early PSCE patients (T1N0M0), only one patient had more than 5 year survival, the others died with less than one or two year (65%). The present study indicates that the PSCE is of badly worsen prognosis, even in the pathological early stage. Tissue CgA protein expression is a promising maker not only for diagnosis and also for prognosis. Further assessment is needed to establish specific PSCE pathological staging system and to clarify the mechanisms of CgA protein in PSCE progression and prognosis.

Resistin-like molecule-β (RELM-β) targets airways fibroblasts to effect remodelling in asthma: from mouse to man

BACKGROUND

RELM-β has been implicated in airways inflammation and remodelling in murine models. Its possible functions in human airways are largely unknown. The aim was to address the hypothesis that RELM-β plays a role in extracellular matrix deposition in asthmatic airways.

METHODS

The effects of RELM-β gene deficiency were studied in a model of allergen exposure in mice sensitised and challenged with Aspergillus fumigatus (Af). RELM-β expression was investigated in bronchial biopsies from asthmatic patients. Direct regulatory effects of RELM-β on human lung fibroblasts were examined using primary cultures and the MRC5 cell line in vitro.

RESULTS

Sensitisation and challenge of wild-type mice with Af-induced release of RELM-β with a time course coincident with that of procollagen in the airways. Af-induced expression of mRNA encoding some, but not all ECM in the lung parenchyma was attenuated in RELM-β-/- mice. RELM-β expression was significantly increased in the bronchial submucosa of human asthmatics compared with controls, and its expression correlated positively with that of fibronectin and α-smooth muscle actin. In addition to epithelial cells, macrophages, fibroblasts and vascular endothelial cells formed the majority of cells expressing RELM-β in the submucosa. Exposure to RELM-β increased TGF-β1, TGF-β2, collagen I, fibronectin, smooth muscle α-actin, laminin α1, and hyaluronan and proteoglycan link protein 1 (Hapl1) production as well as proliferation by human lung fibroblasts in vitro. These changes were associated with activation of ERK1/2 in MRC5 cells.

CONCLUSION

The data are consistent with the hypothesis that elevated RELM-β expression in asthmatic airways contributes to airways remodelling at least partly by increasing fibroblast proliferation and differentiation with resulting deposition of extracellular matrix proteins.

The association between MIF-173 G>C polymorphism and prostate cancer in southern Chinese

BACKGROUND AND OBJECTIVES

Accumulating epidemiological and molecular evidence suggests that inflammation is an important component in the etiology of PCa. Macrophage migration inhibitory factor (MIF) plays an important role in the pro- and anti-inflammatory response to infection. This study is aimed at investigating the potential association between MIF-173 G>C polymorphism, Gleason score, clinical stage, and prostate-specific antigen (PSA) value with respect to PCa incidence among the Han nationality in Southern China.

METHODS

Genotyping was performed by using tetraprimer polymerase chain reaction (PCR) on 259 PCa patients and 301 cancer-free controls.

RESULTS

We found that the MIF-173*C variant allele was significantly associated with an increased risk of PCa [adjusted odd ratio (OR) = 2.99, 95% confident interval (CI): 1.94-4.60] and higher Gleason scores from the PCa subjects (adjusted OR = 10.72, 95% CI: 5.35-21.49). In addition, we noted that the MIF -173*C variant allele was related to higher clinical stages and PSA values in PCa patients (adjusted OR = 15.68, 95% CI: 7.40-33.23; adjusted OR = 4.37, 95% CI: 2.41-7.92, respectively).

CONCLUSION

Our data suggest that MIF-173 polymorphisms may be associated with a higher incidence of prostate cancer compared to controls, and appears to be associated with higher Gleason scores, higher clinical stages, and PSA values in those with prostate cancer.

Pressure assessment in intercavernous embedding of bulboperineal urethra for treatment of urinary incontinence after prostatic operation

AIM

To put forward criteria for the pressure assessment in the operation of intercavernous embedding of bulboperineal urethra for the treatment of urinary incontinence after prostatic operation.

METHODS

A F14 urethral catheter is inserted during the operation and upon suturing the corpora cavemosa centrally, the catheter is slowly pushed in and pulled out in order that the operator feels a certain degree of close-fit resistance. The degree of tightness of the stitches, which regulate the compression pressure, is adjusted in accordance with this close-fit sensation. To further ascertain the adequacy of the force of compression, the bladder is filled with 300 ml physiological saline and observe the appropriateness (size and continuity) of the outflow stream when the lower abdomen is depressed with a pressure of 80-90 cm H2O. The operation was given to six patients suffered from urinary incontinence for 20 or more months after prostatic operation.

RESULTS

Five cases achieved complete recovery, while the therapeutic effect of the 6th one was not satisfactory. A second stage operation was carried out 3 months later with the addition of one more stitch both proximally and distally to reinforce the compression force. The condition was improved dramatically. The follow-up period averaged 3.5 years.

CONCLUSION

The adequacy of the compression pressure exerted by the juxtaposed corpora cavernosa is the key point determining the outcome of the operation. The measures for assessing the compression pressure suggested by the authors are helpful in obtaining the good results of the present paper (6/6 success) as compared with 25/34 success in the previous report.

Examination of the best pressure range for ion/molecule reactions of anthraquinones in an external source ion trap mass spectrometer

This study outlines some observations of the pressure effect for gas phase ion-molecule reactions of anthraquinone derivatives with dimethyl ether in an external source ion trap mass spectrometer. At the reagent pressure of 7.998 x 10(-2) Pa, formation of the protonated ions, [M + 13]+, [M + 15]+, and [M + 45]+ ions, of anthraquinones can be observed. However, at the pressure of 1.066 x 10(-2) Pa, formation of molecular ions and many fragment ions of the M+. or [M + H]+ ions have been observed. Since the pressure effect is notable within a small range of pressures for many compounds, it is important to draw attention to the use of the ion trap with an external source where other factors such as ion source residence time may play a role. This can also provide some information for better and more careful controls of the reagent pressure in order to obtain fair CI spectra in an external source ion trap mass spectrometer.

Selective self-ion/molecule reactions in both external and internal source ion trap mass spectrometers

Novel results on the selective self-ion/molecule reactions (SSIMR) in both external and internal source ion trap mass spectrometers are demonstrated. Selective self-ion/molecule reaction product ions were produced between the oxygenated and nitrogenated crown ethers. For the oxygenated crown ethers, self-ion/molecule reactions lead to the formation of the protonated ions, adduct ions of fragments ([M + F](+)) and [M + H(3)O](+), while the nitrogenated crown ethers produce [M + H](+), [M + CH](+) and [M + C(2)H(3)](+) ions.

Probing reactive sites for ion-molecule reactions of anthraquinones with dimethyl ether using an external source ion trap tandem mass spectrometer and computational chemistry

Gas-phase ion-molecule reactions of anthraquinone derivatives with dimethyl ether (DME) were investigated using an external source ion trap mass spectrometer. Semi-empirical calculations were executed to determine possible reactive sites for the product ions. Collision activated dissociation (CAD) was successfully performed for very low abundance of ion-molecule products. Even for product ions with a relative intensity below 1%, CAD experiments can be successfully performed. Significantly more structural information could be elucidated based on this special feature. Importantly, the CAD spectra of very minor ions could be measured by this ion trap instrument, which significantly enhances the future role of the ion trap as a powerful analytical instrument. CAD of all product ions on anthraquinone compounds typically eliminates neutral molecules such as CO or H(2)O. A hydration phenomenon in the CAD processes resulting from the precursor ions incorporating one molecule of H(2)O and then eliminating one molecule of CO was observed in this study.

Current awareness

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (6 Weeks journals - Search completed at 7th. June 2000)

[Detection of distortion-product otoacoustic emissions in well-drilling workers]

OBJECTIVE

To understand the value of using distortion product of otoacoustic emissions(DPOAE) in monitoring noise-induced hearing-loss.

METHOD

The amplitude and the positive rates of DPOAE were detected in 102 well-drilling workers (195 ears).

RESULT

The amplitude and the positive rates of DPOAE declined significantly in noise groups against control. With the increase of working-age the positive rates of DPOAE was decrease. The DPOAE amplitudes and the positive rates of noise group with normal pure tone threshold were obvious lower than that in controls. There were negative relationship between pure tone threshold in high-frequency and the positive rates.

CONCLUSION

The DPOAE can reflect the cochlea's function of labors working in noise condition well. Contrast with the pure tone audiometry, DPOAE was more sensitive and more objective.

Effect of liposomes on mineralization in rat osteoblast-enriched cultures

Liposomes, artificial membranous lipid vesicles, have been used as model structures for biological calcification processes. However, there is no definite conclusion that liposomes can be like matrix vesicles for inducing bone calcification and bone-like tissue formation on primary cultured cells. To determine whether liposomes can promote bone cell growth and mineralization by inducing crystal nucleation, liposomes composed of egg phosphatidylcholine, cholesterol, and bovine brain phosphatidylserine were added to 21-day-old Sprague-Dawley fetal rat calvarial cell cultures from day 1. The aims were to observe proliferation and the phenotype of osteoblasts by measuring cell numbers and alkaline phosphatase (ALP) activity and, when added at confluence, to observe calcification. The data were analyzed with two-way ANOVA. During the 16-day culture period, cell numbers were not significantly affected by liposomes (100 mumol/L). However, ALP activity was significantly inhibited by liposomes (p < 0.05) at day 16 and thereafter. Calcified particles were detected by von Kossa's method, and were larger and more abundant (p < 0.05) in the liposomes groups than in the control from days 12-24. This response depended on liposomes dose. These findings suggest that liposomes promote calcification and accelerate the formation of bone-like tissue. Liposomes slightly reduce the expression of the osteoblast phenotype and do not affect cell growth in primary rat osteoblast-enriched cultures.

Evoked facial nerve EMG and brainstem auditory evoked potential monitoring in cerebellopontine angle tumor resection

BACKGROUND

The preservation of normal nerve function or identification of nerve route is critical in some surgeries of cerebellopontine angle tumors. Over the last 5 years, intraoperative facial nerve electromyogram (EMG) and brainstem auditory evoked potential (BAEP) were applied for evaluation of facial nerve integrity and brainstem function in patients while undergoing resection of cerebellopontine angle (CPA) tumor. This report represents the retrospective analysis of our results.

METHODS

The inhalational anesthesia with 1-1.5% isoflurane in pure O2 was used. Muscle relaxation was maintained with continuous infusion of atracurium. The degree of muscle relaxation was aimed at a T4/T1 ratio of train-of-four response more than 20% of the adductus pollicis upon ulnar nerve stimulation at the wrist. In 236 patients suffering from CPA tumor without facial palsy, the EMG of the mentalis muscle ipisilateral to the tumor was obtained through stimulation of the facial nerve. The stimulation was applied with a nerve finder, which delivered an electrical stimulation of a single 2 mamp direct current. The EMG finding was compared with the clinical result. In 198 patients, BAEP was used to monitor the brainstem function during tumor resection. In case of intact hearing the BAEP was taken ipsilateral to the operation side and in case with total hearing loss contralateral BAEP to operation side was used. For BAEP stimulation, 90 db click sound stimulation with frequency of 11.26 Hz was applied to both ears. BAEP signals were obtained and recorded at the mastoid region of either side in reference to the vertex. The EMG and BAEP signals were recorded and saved to an evoked potential monitor.

RESULTS

In facial nerve EMG monitoring, there were two false positive and no false negative tests. Except for the two false positive tests, the postoperative clinical results in the other cases were compatible with the intraoperative facial nerve EMG findings. In BAEP monitoring, there were twenty-eight positive tests.

CONCLUSIONS

The low incidence of false negative test suggests that facial nerve EMG is valuable in detection of facial nerve function in CPA tumor resection. Intraoperative BAEP abnormality is possibly useful in identifying postoperative brainstem dysfunction.

[A systematic screening and identification method for 29 central nervous system drugs in body fluid by high performance capillary electrophoresis]

A systematic screening method has been developed for the detection of 29 central nervous system (CNS) drugs in human plasma, urine and gastric juice by high performance capillary electrophoresis (HPCE). The first step is sample preparation. The patient's or normal human plasma (0.5 ml) spiked with CNS drugs was extracted with 2 x 4 ml dichloromethane, while 2 ml of patient's or spiked urine was extracted with 2 x 6 ml chloroform. The combined extract from plasma or urine was evaporated to dryness in a rotation evaporator at 35 degrees C. The residue was dissolved in 100 microliters methanol and subsequently 400 microliters of redistilled water was added. The patient gastric juice (3 ml) was centrifuged at 2,000 r.min-1 for 5 min. The supernatant was filtered through 0.45 micron microporous membrane for injection onto capillary columns. The second step was to perform CZE separation in acidic buffer composed of 30 mmol.L-1(NH4)3PO4(pH 2.50) and 10% acetonitrile (condition A). Most of the benzodiazepines (diazepam, nitrazepam, chlordiazepoxide, flurazepam, extazolam, alprazolam) and methaqualone were baseline separated and detected at 5-13 min, while thiodiphenylamines showed group peaks at 3-5 min and barbiturates migrate with electroosmotic fluid (EOF) together. The third step is to separate the drugs in basic buffer constituted of 70 mmol.L-1 Na2HPO4(pH 8.60) and 30% acetonitrile (condition B). The thiodiphenylamines and some other basic drugs could be well separated, which include thihexyphenidyl, imipramine, amitriptyline, diphenhydramine, chlorpromazine, doxepin, chlorprothixene, promethazine and flurazepam, while the rest of the CNS drugs did not interfere with the separation. The last step was to separate the drugs by micellar electrokinetic chromatography (MEKC) in such a buffer as 70 mmol.L-1 SDS plus 15 mmol.L-1 Na2HPO4 (pH 7.55) and 5% methanol (condition C). Barbiturates (barbital, phenobarbital, methylphenobarbital, amobarbital, thiopental, pentobarbital, secobarbital) and some hydrophobic drugs (glutethimide, alprazolam, clonazepam, carbamazepine, trifluoperazine, oxazepam) could be well separated. These drugs might be identified by both the relative migration time (rtm = tdrug/tEOF) and the ratios of peak heights (rh) monitored at different wavelength, since the ratios are characteristic of the spectrum of a drug. This method has been used in several real clinical samples of intoxication. For example, perphenazine and doxepin were detected in the gastric juice and phenobarbital in blood and gastric juice of an intoxicated patient.

Influence of C terminus on monoamine oxidase A and B catalytic activity

Monoamine oxidase (MAO) A and B play important roles in the metabolism of neurotransmitters and dietary amines. The domains important for enzyme specificities were studied by construction of chimeric MAOA/B enzymes. Exchange of the N-terminal 45 amino acids of MAOA with the N-terminal 36 residues of MAOB (chimeric enzymes B36A and A45B) resulted in the same substrate and inhibitor sensitivities as the wild-type MAOA or B. Thus, the N terminus may not be responsible for MAOA or B enzyme specificities. When MAOB C-terminal residues 393-520 were replaced with MAOA C-terminal residues 402-527 (chimeric B393A) catalytic activity was not detectable. Chimeric B393A consists of eight residues with different charges, three less proline residues (458, 476, and 490), and one additional proline at 518 compared with wild-type MAOB. These differences may have induced conformational changes and affected MAOB catalytic activity. Thus, the C terminus of MAOB is critical for maintaining MAOB in an active form. It is interesting that when the C terminus of MAOA was switched with MAOB (chimeric A402B), little effect was observed on MAOA catalytic activity. This new information is valuable for further studies of the structure and function relationship of this important enzyme.

Monocyte chemoattractant activity of Ser195-->Ala active site mutant recombinant alpha-thrombin

alpha-Thrombin is chemotactic for human monocytes with optimal activity between 10-100 nM. The mechanism by which this response is mediated remains a point of controversy. The purpose of this study was to compare the chemotactic activity of proteolytically inactive thrombin (active site Ser195-->Ala mutant or Phe-Pro-Arg-chloromethyl ketone-inactivated thrombin) to thrombin and the "tethered ligand" thrombin receptor agonist peptide SFLLRN (single-letter amino acid code). Monocyte chemotaxis was compared to an optimal concentration (10 nM, considered to be 100%) of formyl-Met-Leu-Phe (fMLP). Proteolytically inactive thrombin (38% of fMLP) had similar chemotactic activity to active thrombin (46% of fMLP) at a concentration of 100 nM. Chemotaxis to SFLLRN was comparable to that of a control hexapeptide (FSLNLR) which is not an agonist for the tethered ligand thrombin receptor. Cross-desensitization experiments showed that pretreatment of monocytes with either mutant or active thrombin reduced subsequent chemotaxis to both thrombin chemotaxins. Pretreatment with SFLLRN did not decrease subsequent chemotaxis to either form of thrombin. Calcium flux measurements showed that both active thrombin and SFLLRN induced a rapid increase in monocyte and platelet intracellular calcium concentration. However, there was no intracellular calcium change in response to mutant thrombin or FSLNLR. Likewise, active thrombin and SFLLRN induced a rapid net increase in polymerized actin, but mutant thrombin and FSLNLR did not. By contrast, both active and mutant thrombin induced a polarization of monocyte morphology and actin distribution. This polarization has been associated with directed migration in many cell types. SFLLRN, however, induced a symmetrical increase in polymerized actin. These results suggest that measurements of intracellular calcium and polymerized actin are not perfect surrogate tests for true chemotactic activity. These results show that thrombin proteolysis is not required for monocyte chemotaxis and may be mediated by interaction with a binding site other than the tethered ligand thrombin receptor.

Characterization of the glycosaminoglycan-binding region of lactoferrin

Lactoferrin is a prominent component of neutrophil secondary granules and its blood concentration is increased in certain inflammatory diseases. Although the biochemical characterization of lactoferrin as an iron-binding protein has been well described, its physiological role in inflammation remains undefined. We examined the ability of lactoferrin to regulate glycosaminoglycan-accelerated thrombin-serine protease inhibitor (serpin) reactions. Lactoferrin effectively reduced the rate of thrombin-serpin (antithrombin and heparin cofactor II) reactions by three physiological glycosamino-glycans including heparin, heparan sulfate, and dermatan sulfate. An enzyme kinetics analysis showed that lactoferrin did not alter the apparent heparin-thrombin or the heparin-antithrombin dissociation constant values for the heparin-catalyzed thrombin-antithrombin reaction. However, the maximum reaction velocity at saturation with respect to either protein was markedly decreased by lactoferrin. The glycosaminoglycan-binding region of lactoferrin was analyzed following limited proteolysis using Staphylococcus aureus V8 protease. Two lactoferrin fragments with Mr's of approximately 8 and approximately 11 kDa were purified based on their affinity to heparin-Sepharose. Amino acid sequence analysis demonstrated that both peptides were from the N-terminus. Although slightly less capable compared to intact lactoferrin, the lactoferrin peptides effectively neutralized heparin, heparan sulfate, and dermatan sulfate-catalyzed serpin-thrombin inhibition reactions. In addition, lactoferrin N-terminal peptides have approximately the same binding affinity to heparin-Sepharose as that of intact lactoferrin. Inspection of both the N-terminal amino acid sequence and the crystal structure of lactoferrin further supports the conclusion that lactoferrin is a novel glycosaminoglycan binding protein and that the putative glycosaminoglycan-binding site is localized to the N-terminus.

Neutralization of heparin activity by neutrophil lactoferrin

Lactoferrin is a prominent component of neutrophil secondary granules, and its blood concentration is increased in certain inflammatory diseases. In contrast to the well-described biochemical characterization of lactoferrin as an iron-binding protein, its physiologic role in the regulation of inflammation and other host defense mechanisms is unclear. In this report, we provide evidence that lactoferrin has a potent heparin-neutralizing activity during thrombin inhibition by the serine proteinase inhibitors (serpins) antithrombin and heparin co-factor II. Activated neutrophil supernatant, which contains lactoferrin and other heparin-binding proteins, could neutralize the heparin-dependent antithrombin-thrombin inhibition reaction. The addition of lactoferrin to plasma corrected the heparin-induced prolongation of blood plasma coagulation as measured by the activated partial thromboplastin time (aPTT). Treatment of whole blood with specific inflammatory mediators, fMLP, lipopolysaccharide (LPS), and tumor necrosis factor-alpha (TNF-alpha) increased the concentration of both plasma lactoferrin and platelet factor 4 while inhibiting the blood anticoagulant activity of heparin as measured by the aPTT. These results suggest that the prothrombotic sequelae of some inflammatory processes may be partly due to various agonists that release neutrophil lactoferrin, which can then neutralize glycosaminoglycan-dependent serpin-thrombin inhibition reactions.

Cloning of a novel monoamine oxidase cDNA from trout liver

A trout liver monoamine oxidase (MAO) cDNA was cloned by screening a cDNA library with a human MAO-A cDNA probe. The trout MAO cDNA encodes 499 amino acids, with a molecular mass of 56.6 kDa. The deduced amino acid sequence of trout MAO shows 70% and 71% identity with those of human MAO-A and MAO-B, respectively. Trout MAO contains the pentapeptide sequence Ser-Gly-Gly-Cys-Tyr, to which the cofactor FAD is covalently bound. Transient expression of the cDNA in COS-7 cells shows that trout MAO oxidizes both serotonin [5-hydroxytryptamine (5-HT)] and beta-phenylethylamine (PEA), unlike human MAO-A and MAO-B, which oxidize only 5-HT and PEA, respectively. The Km for 5-HT is similar for trout MAO (130 +/- 17 mM) and human MAO-A (68 +/- 4 mM). The Km for PEA is similar for trout MAO (12.5 +/- 2.0 mM) and human MAO-B (1.5 +/- 0.2 mM). When 5-HT is used as a substrate, trout MAO is more sensitive to clorgyline (IC50, 2.8 +/- 0.2 x 10(-8) M) than deprenyl (IC50, 1.0 +/- 0.1 x 10(-6) M), a result similar to the inhibition selectivity of human MAO-A. However, trout MAO is less sensitive to clorgyline than is human MAO-A (IC50, 5.8 +/- 0.1 x 10(-10) M). Trout MAO is less sensitive to deprenyl (IC50, 4.6 +/- 0.3 x 10(-7) M) than is human MAO-B (IC50, 1.4 +/- 0.1 x 10(-9) M) when PEA is used as the substrate. These results indicate that trout MAO displays substrate and inhibitor selectivities that are not identical to those of either MAO-A and -B, and it therefore represents a novel type of MAO. The structure of trout MAO will provide insights into the substrate and inhibitor selectivities of the MAOs.

Hydrogen-bonding interactions in gas-phase polyether/ammonium ion complexes

Hydrogen bonds are among the most important interactions involved in selective complexation in host-guest chemistry. In this study a variety of hydrogen-bonded crown ether/ammonium ion complexes are generated in the gas phase by association reactions between an amine substrate and a polyether, one of which is initially protonated, and stabilized by many collisions in the chemical ionlzation source of a triple quadrupole mass spectrometer or in a quadrupole ion trap. The nature of the hydrogen-bonding interactions of the ion complexes are evaluated by comparison of their collision-activated dissociation spectra. After collisional activation, those complexes that are weakly bound dissociate to form intact protonated polyether molecules and/or ammonium ions by simple cleavages of the hydrogen-bond association interactions. In contrast, those complexes strongly bound by multiple hydrogen bonds dissociate not only to the protonated polyether and/or ammonium ions but also by extensive covalent bond cleavage of the protonated ether skeleton.This latter type of dissociation behavior suggests that the polyether/ammonium ion complexes may be sufficiently strongly bound that surpassing the high barrier to decomposition results in formation of internally excited polyether molecules that may then undergo subsequent fragmentation by skeletal cleavages. Moreover, complexes involving multiple hydrogen bonds may have slower dissociation kinetics, allowing competition from fast dissociation processes that have substantial energy barriers.

Comparison of the orders of gas-phase basicities and ammonium ion affinities of polyethers by the kinetic method and ligand exchange technique

The orders of relative gas-phase basicities and ammonium ion affinities of a series of polyethers obtained by application of the kinetic method and ligand exchange technique are compared to evaluate the discrepancies of results between the two techniques. The order of gas-phase basicities determined by the ligand exchange technique in a quadrupole ion trap agrees with the order established previously by Kebarle using equilibrium methods in a high-pressure mass spectrometer. The order obtained by the kinetic method in a triple quadrupole mass spectrometer varies for the ranking of one polyether (12-crown-4), and this discrepancy is attributed to a difference in the rates of the competing dissociation pathways from the triethylene glycol dimethyl ether/12-crown4 proton-bound adduct, owing to a substantial variation in the flexibilities of these two ethers. For the order of gas-phase ammonium ion affinities, the kinetic method results agree overall with the ligand exchange results; however, the order of ammonium ion affinities for tetraethylene glycol dimethyl ether and 15-crown-5 could not be differentiated by the ligand exchange method because of the rapidity of ammonium ion transfer between the two polyethers in both directions.

The deduced amino acid sequences of human platelet and frontal cortex monoamine oxidase B are identical

Monoamine oxidases (MAOs) A and B play important roles in the metabolism of neuroactive, vasoactive amines. Human platelets contain only MAO B, often used as an indicator of brain MAO B. The validity of this model remained to be evaluated. This report describes the molecular cloning of human MAO B from frontal cortex and platelets. Two overlapping PCR-amplified clones of human platelet MAO B and four PCR-amplified clones of human frontal cortex MAO B covering the entire coding region were sequenced using five internal oligomers and M13 reverse and forward primers. The nucleotide sequences of human MAO B cDNA from platelet and frontal cortex were identical to that of human liver MAO B except for three nucleotides that differed in frontal cortex: nucleotides 440 A-->G, 794 C-->T, and 825 C-->T. Whether or not these differences are artifactual, all three represent silent mutations, which would not alter the amino acid of the encoded polypeptides. Thus, the deduced amino acid sequences of MAO B from frontal cortex, platelet, and liver are identical. These findings indicate the validity of using platelet MAO B mRNA as a marker for brain MAO B and provide a new approach to study the role of brain MAO B in humans.

Site-directed mutagenesis of monoamine oxidase A and B: role of cysteines

Nine cysteines are found in the deduced amino acid sequences of both human liver monoamine oxidase (MAO)-A and MAO-B. The role of these cysteine residues in MAO-A and -B catalytic activity was studied by site-directed mutagenesis, whereby each cysteine residue was converted to serine. The wild-type and mutant cDNAs were then transiently transfected into COS cells and assayed for MAO-A and -B catalytic activity using 5-[3H]hydroxytryptamine and [14C]phenylethylamine, respectively, as substrates. Catalytic activities were retained in seven MAO-A cysteine to serine mutants (mutations at residues 165, 210, 266, 306, 321, 323, and 398) and in six MAO-B cysteine to serine mutants (mutations at residues 5, 172, 192, 297, 312, and 389). Kinetic parameters (Km) of these mutants were also similar to those of the wild-type enzymes, indicating that these cysteines are not necessary for enzymatic activity. Substitution of MAO-A Cys-374 and -406 and MAO-B Cys-156, -365, and -397 with serine resulted in complete loss of MAO-A and -B catalytic activity. The loss of catalytic activity was not due to unsuccessful transfection of the mutants, as indicated by either Northern blot or Western blot analysis. The loss of catalytic activity in the MAO-A Ser-406 and MAO-B Ser-397 mutants may be due to the prevention of covalent binding of the enzyme to the cofactor FAD, which is necessary for catalytic activity. The loss of catalytic activity of MAO-A Ser-374 and MAO-B Ser-156 and -365 suggests that these cysteines are important for catalytic activity, but whether they are involved in forming the active site or are important for the appropriate conformation of MAO-A and -B remains to be studied.

Hydrophobic affinity chromatography of human thrombin

Hydrophobic affinity chromatography on p-chlorobenzylamido-agarose (p-CBA-agarose) was used to characterize various modified forms of human thrombin. Native alpha-thrombin bound tightly to the column and was eluted with either acetonitrile or 1,4-dioxane, while the catalytically inactive prethrombin 2 did not bind to the matrix. Site-specific chemical modification with pyridoxal 5'-phosphate resulted in the loss of at least 80% of fibrinogen clotting activity but did not influence the binding of thrombin to p-CBA agarose. Modification of thrombin with pyridoxal 5'-phosphate is thought to occur at the fibrinogen-binding site and the heparin-binding site. In contrast, binding of thrombin to p-CBA agarose was eliminated by modification of the active site histidine using either H-D-phenylalanyl-L-prolyl-L-arginine chloromethylketone or dansyl-L-glutamyl-glycyl-L-arginine chloromethylketone but not with tosyl-L-lysine chloromethylketone. The presence of either hirudin or heparin blocked the binding of thrombin to p-CBA-agarose but dansyl-arginine-N-(3-ethyl-1,5-pentanediyl)amide had no effect. These results indicate that p-CBA agarose binds to thrombin outside of the enzyme active site and its use should be valuable in characterizing site-specific modified thrombins obtained by either protein engineering or chemical modification.

Identification of tissue kallikrein messenger RNA in human neutrophils

Expression of tissue kallikrein in human neutrophils has been suggested by previous studies using enzymatic and immunochemical techniques. Secretion of this potent biological factor by neutrophils would be of marked significance in the inflammatory process. The present study utilized the polymerase chain reaction following reverse transcriptase generation of total neutrophils cDNA to demonstrate the presence of tissue kallikrein mRNA in the human neutrophils. In addition, use of sequence-specific primers demonstrated the presence of mRNA for the hGK-1 gene, but not for the hPK gene product or the gene for prostate-specific antigen. These results confirm that tissue kallikrein is present in neutrophils and may be secreted as part of the inflammatory process.

Expression of tissue kallikrein in normal and SV40-transfected human endometrial stromal cells

The polymerase chain reaction with specific tissue kallikrein primers was utilized to demonstrate the presence of tissue kallikrein mRNA in human endometrial stromal cells. Enzymatic analysis measured with a specific tripeptide nitroanilide substrate demonstrated the presence of tissue kallikrein in the conditioned medium obtained from both normal stromal cells and stromal cells transfected with an origin-defective temperature-sensitive SV40 large T antigen. The transfected stromal cell supernatant exhibited approximately twice as much tissue kallikrein activity as normal stromal cells at 60-100% of cell confluence. The release of tissue kallikrein from transfected stromal cells was confirmed by Western blot analysis and [35S]-methionine incorporation into a 35-kD protein which retains tissue kallikrein activity. These results demonstrate for the first time the expression and secretion of tissue kallikrein in human endometrial stromal cells and provide evidence of possible involvement of tissue kallikrein in cell transformation.

Affinity chromatography of platelets on immobilized thrombin: retention of catalytic activity by platelet-bound thrombin

Radioactivity from I125-labeled human platelets was measured to estimate the extent of binding of platelet surface proteins to immobilized thrombin. 1-3% of the radioactivity was bound with 10-20% of this amount apparently irreversibly bound to the thrombin matrix. Site-specific chemical modification of thrombin with pyridoxal-5'-phosphate, N-bromosuccinimide or tetranitromethane resulted in a variable reduction of the amount of radiolabel bound. When thrombin modified with H-D-PheProArg-chloromethyl ketone (PPACK) was coupled to the matrix, there was no difference in the binding of platelet membrane proteins when compared to a control thrombin preparation while thrombin modified with tosyl-Lys-chloromethyl ketone (TLCK) coupled to the matrix did not bind radiolabel any more effectively than albumin which served as the control. However, when thrombin was modified with PPACK after coupling to the agarose matrix, ability to bind radiolabel was lost. Thrombin bound to platelets remained catalytically active when assayed with a peptide nitroanilide substrate. These results suggest tight binding between thrombin and platelets that is not only not dependent on active site integrity but leaves the bound thrombin catalytically competent.

Linkage between blood coagulation and inflammation: stimulation of neutrophil tissue kallikrein by thrombin

There has been major interest in the potential interaction between blood coagulation and inflammation. Most of the effort has focused on cellular interactions involving platelets and polymorphonuclear leukocytes (PMNS). The recent discovery of tissue kallikrein(TK) activity in PMNs prompted the study of the possible role of thrombin(IIa) in this process. Human PMNs were isolated by density gradient centrifugation. Human IIa was compared with fMLP with respect to chemotaxis and enzyme release. Results from the challenges by IIa and fMLP were compared to a NaCl control using Student's paired t-test. IIa was a potent chemotactic agent for PMNs (p less than or equal to 0.0121) and stimulated the release of TK (p less than or equal to 0.0001) as determined by hydrolysis of S-2266. FMLP significantly stimulated PMN chemotaxis (p less than or equal to 0.0028) but had no effect on TK release. Release of TK was confirmed by Western Blot analysis and 35S-methionine incorporation into a 35 KD protein after IIa challenge. These results demonstrate that IIa is chemotactic for PMNs and can cause release of tissue kallikrein demonstrating a direct role for blood coagulation in the regulation of the inflammatory response.