梅钢三烧结节能环保生产实践

梅钢三烧结建设投产于2004年,随着运行年限的增加,其原有装备条件及技术水平逐步不适应目前的能源环保要求。近几年,三烧结厂结合自身的发展需求,通过技术设备升级改造,采用节能环保新技术,如主抽变频技术、竖冷炉技术、循环流化床脱硫技术以及臭氧氧化脱硝技术等,使三烧结的节能环保水平得到了大幅提升,能耗水平下降到45.6 kg/t,烧结烟气经处理后排放指标SO₂浓度小于35 mg/m3、NO_x浓度小于50 mg/m3,粉尘浓度小于10 mg/m3,达到超低排放指标要求。     

The role of transcription factor PU.1 in the activity of the intronic enhancer of the eosinophil-derived neurotoxin (RNS2) gene

PURPOSE: To evaluate the therapeutic significance of cisplatin, vincristine, doxorubicin, and etoposide (CODE) plus granulocyte colony-stimulating factor (G-CSF) compared with cyclophosphamide, doxorubicin, and vincristine, alternating with cisplatin and etoposide (CAV/PE) for extensive-disease (ED) small-cell lung cancer (SCLC). PATIENTS AND METHODS: Two hundred twenty-seven patients were randomized. CODE consisted of cisplatin 25 mg/m2 weekly for 9 weeks; vincristine 1 mg/m2 on weeks 1, 2, 4, and 6; and doxorubicin 40 mg/m2 and etoposide 80 mg/m2 for 3 days on weeks 1, 3, 5, 7, and 9. G-CSF 50 micrograms/m2 was administered on the days when chemotherapy was not administered. CAV/PE consisted of cyclophosphamide 800 mg/m2; doxorubicin 50 mg/m2; and vincristine 1.4 mg/m2 on day 1, which alternated every 3 weeks with cisplatin 80 mg/m2 on day 1 and etoposide 100 mg/m2 on days 1 to 3. RESULTS: Overall response rates were 77% for the CAV/PE arm and 84% for the CODE arm respectively (15% complete response in both arms). The median survival times were 10.9 months in the CAV/PE arm and 11.6 months in the CODE arm (P = .1034). The achieved dose-intensity for CODE was approximately twice that for CAV/PE for those drugs common to both arms. The incidence of leukopenia did not differ between the two arms, but anemia and thrombocytopenia had a significantly higher incidence in the CODE arm. Four treatment-related deaths from neutropenic fever occurred in the CODE arm. CONCLUSION: The CODE group had a similar median survival to the CAV/PE group. It does not appear that CODE is a useful approach to improve survival in ED SCLC.     

Origin of nondisjunction in trisomy 8 and trisomy 8 mosaicism

OBJECTIVES: This study explores reactions to low-level chemical challenge, aiming at the development of test procedures for assessing individual sensitivity to smells and chemicals. METHODS: Subjects with symptoms and neuropsychological test results compatible with toxic encephalopathy type 2A (TE-2A) and 2B (TE-2B) and unexposed referents (N=12 in each group) were challenged in an exposure chamber. Toluene exposure was started at 11 mg/m3, and it followed a geometric progression scale with a ratio of 2, until reaching 180 mg/m3. In a counterbalanced design, the subjects were similarly exposed to n-butyl acetate starting at a concentration of 14 mg/m3 and increasing to 228 mg/m3. At each exposure level, smell intensity was measured on a 7-step category scale. Mucous membrane irritation and annoyance reactions were rated on visual analogue scales. RESULTS: Both TE groups showed high sensitivity to the low-level solvent challenge, which provoked immediate annoyance and fatigue reactions. In particular the TE-2B group related smell intensity to various annoyance dimensions during exposure to n-butyl acetate, a pattern not observed during toluene exposure. The reference group clearly separated smell intensity and annoyance reactions in both exposure conditions. CONCLUSIONS: The reaction of the TE cases suggests that chemical sensitivity can be distinguished from normal annoyance reactions by the inability to differentiate between smell intensity and an experience of irritation from mucous membranes in air concentrations well below the trigeminal irritation threshold level. Fatigue coreactivity in challenges to single substances below the neurotoxic level may also be important.     

The establishment of the maximum permissible concentration of orlok in the air of a work area when used in agriculture

Inhaled Orlok causes changes in the CNS, blood morphology, renal function. The threshold concentration of Orlok is 0.17 mg/m3, its subthreshold concentration is 0.023 mg/m3, MAC in the workplace air is 0.05 mg/m3.     

Anesthesia for pediatric herniorrhaphy or hydrocelectomy: comparison of propofol/ketamine and thiopentone/halothane

In this study we have measured exposure levels to quartz in different parts of the slate industry in Alta, Northern Norway. Full shift personal samples were collected from the breathing zones of outdoor and indoor workers in the slate quarries and a slate factory. The quartz content of respirable dust was between 7 and 41%. The slate factory had the lower quartz levels although 41% of total and 73% of respirable samples were above the Norwegian TLV for quartz. The average concentration of total quartz in the slate factory was 0.27 mg/m3 and the average concentration of respirable quartz was 0.12 mg/m3. Outdoor in the quarries the average levels of quartz were 0.58 and 0.13 mg/m3 for total and respirable quartz, respectively. From the beginning of the last decade most of the quarry-workers have built quarry halls to protect themselves against a cold winter climate. Inside in these quarry halls the average levels were 1.74 mg/m3 total quartz and 0.46 mg/m3 respirable quartz. Assessment of historical exposure showed that 32 of totally 45 quarry workers with available exposure history had a lifetime inhaled quartz dose of more than 10 g. There is reason to fear that silicosis will be an increasing problem among quarry workers if efforts to reduce quartz exposure are not put into effect.     

全氧高炉风口喷吹烧结烟气的冶炼特征

摘要：建立了高炉或氧气高炉喷吹烧结烟气的数学模型,实现对烧结烟气利用与处理的目的。模拟结果显示：当烧结烟气喷吹温度为1250℃,全氧高炉的炉缸与炉身处各循环200m3/t炉顶煤气时,烧结烟气喷吹量每增加100m3/t,高炉理论燃烧温度降低约134℃,直接还原度增大0.02。随着烧结烟气喷吹量的增加,煤比逐渐增大,炉顶煤气中氮气含量逐渐增大,SO2浓度逐渐降低。当烧结烟气喷吹量达到894m3/t时,炉顶煤气中的SO2质量浓度为214.28mg/m3,与普通高炉相比,降低约1.48mg/m3;氮氧化物质量浓度为45.42mg/m3,低于普通高炉约6.36mg/m3。     

Industrial manufacture of parenteral products in The Netherlands. A survey of eight years of media fills and sterility testing

BACKGROUND: Etoposide is a cytotoxic agent which is frequently employed in paediatric oncology and which is available for intravenous as well as oral application. Many advantages of the formulation for oral use have been opposed by concerns about its interindividually varying bioavailability. The influence of the dosage of etoposide on its activity and toxicity ("schedule dependency") has also been discussed. The present paper deals with the pharmacokinetics of oral etoposide focusing on the interindividual variability. PATIENTS: Sixteen patients aged between 3 and 73 years received oral etoposide at a dosage of 28 mg/m2 to 149 mg/m2 in combination with oral trofosfamide for palliation. METHOD: HPLC was used to measure total and free serum etoposide in 16 patients, and the etoposide concentration in several urine samples from 8 patients. Pharmacokinetic parameters were normalized to a dosage of 100 mg/m2. RESULTS: The peak serum concentration, the time to peak concentration, the area under the concentration-time curve, the terminal half-life and the apparent clearance after oral application were calculated to be 6.7 micrograms/ml, 2.1 h, 51.8 (microgram.h/ml)/(100 mg/m2), 5.6 h, and 40.3 ml/min for total etoposide, and 0.23 microgram/ml, 1.9 h, 1.76 (microgram.h/ml)/ (100 mg/m2), 5.9 h, and 1172 ml/min for free serum etoposide, respectively. On an average, urinary recovery of etoposide was 21% of the oral dose. The fraction of free etoposide was calculated to be close to 4%. Regarding the systemic exposure to etoposide, a variation coefficient of 40% was determined. Additional studies showed that the interindividual variability mainly concerned the peak levels, while the duration for which intermediate etoposide levels were maintained varied less between individuals. On simulating different dosage schedules, it was seen that the duration of intermediate concentrations (0.5-2 micrograms/ml) may be extended significantly by dividing the daily dose of etoposide into two oral applications. CONCLUSION: The total systemic exposure under oral etoposide treatment varies considerably between individuals. Extended intervals of intermediate etoposide concentration and less variation are, however, possible with oral therapy. Dividing the daily dose into two applications seems advisable. Future studies are warranted to test hypotheses on pharmacokinetic-pharmacodynamic aspects by pharmacological drug monitoring.     

Pharmacokinetics of enrofloxacin after intravenous, intramuscular and oral administration in houbara bustard (Chlamydotis undulata macqueenii)

The in-vitro activity of enrofloxacin against 117 strains of bacteria isolated from bustards was determined. Minimum inhibitory concentrations for 72% of the Proteus spp., E. coli, Salmonella spp. and Klebsiella spp. (n = 61) and for 48% of the Streptococci spp. and Staphylococci spp. (n = 31) were < or = 0.5 microg/mL. The minimum inhibitory concentration (MIC) of 76% of Pseudomonas spp. (n = 25) was < or = 2 microg/mL. Fourteen strains were resistant to concentrations > or = 128 microg/mL. The elimination half-lives (t1/2 elim beta) (mean +/- SEM) of 10 mg/kg enrofloxacin in eight houbara bustards (Chlamydotis undulata) were 6.80 +/- 0.79, 6.39 +/- 1.49 and 5.63 +/- 0.54 h after oral (p.o.), intramuscular (i.m.) and intravenous (i.v.) administration, respectively. Enrofloxacin was rapidly absorbed from the bustard gastro-intestinal tract and maximum plasma concentrations of 1.84 +/- 0.16 microg/mL were achieved after 0.66 +/- 0.05 h. Maximum plasma concentration after i.m. administration of 10 mg/kg was 2.75 +/- 0.11 microg/mL at 1.72 +/- 0.19 h. Maximum plasma concentration after i.m. administration of 15 mg/kg in two birds was 4.86 microg/mL. Bioavailability was 97.3 +/- 13.7% and 62.7 +/- 11.1% after i.m. and oral administration, respectively. Plasma concentrations of enrofloxacin > or = 0.5 microg/mL were maintained for at least 12 h for all routes at 10 mg/kg and for 24 h after i.m. administration at 15 mg/kg. Plasma enrofloxacin concentrations were monitored during the first 3 days of treatment in five houbara bustards and kori bustards (Ardeotis kori) with bacterial infections receiving a single daily i.m. injection of 10 mg/kg for 3 days. The mean plasma enrofloxacin concentrations in the clinical cases at 27 and 51 h (3.69 and 3.86 microg/mL) and at 48 h (0.70 microg/mL) were significantly higher compared with the 3 h and 24 h time intervals from clinically normal birds. The maximum plasma concentration (Cmax)/MIC ratio was ranked i.v. (10/mg/kg) > i.m. (15 mg/kg) > i.m. (10 mg/kg) > oral (10 mg/kg), but it was only higher than 8:1 for i.v. and i.m. administrations of enrofloxacin at 10 mg/kg and 15 mg/kg, respectively, against a low MIC (0.5 microg/mL). A dosage regimen of 10 mg/kg repeated every 12 h, or 15 mg/kg repeated every 24 h, would be expected to give blood concentrations above 0. 5 microg/mL and hence provide therapeutic response in the bustard against a wide range of bacterial infections.     

胶带运输巷道粉尘分布规律及其控制

通过对245胶带运输巷道内粉尘浓度的现场测定与分析,发现转载点和落矿点的粉尘浓度严重超标。为此,建立井下运输巷道的物理模型,采用Fluent软件对胶带运输巷道粉尘运动进行数值模拟研究,确定了巷道内粉尘运移规律。结果表明:当平均风速为3 m/s时,巷道内粉尘浓度最低; 巷道内粉尘浓度大小与胶带运行速度成正比。根据数值模拟的结果,结合某大型金属矿山的实际情况,制定了一套适用于胶带运输巷道的降尘措施。该措施实施后,胶带运输巷道内粉尘浓度最大的落矿点处由60.5 mg/m3降低到9.5 mg/m3,降尘效果显著,巷道内作业环境得到较大改善。      

改性污泥燃烧过程研究及烟气评估

原生污泥经M1固化剂、木屑与煤粉按100：5：10：20（w／w）比例混合均匀,自然风干5d后制得改性污泥燃料。改性污泥燃烧结果表明：燃烧的经济风速为1～4m／s;燃烧时间随通风风速增大,颗粒粒径减小而减少．且颗粒粒径的影响较为显著;理想通风条件下,改性污泥燃烧烟气中SO2的浓度为44．6mg／m3,比原生污泥降低了52．4％,与煤粉SO2浓度相近;实际燃烧过程中,颗粒物浓度达到276mg/m3。     

Pharmacokinetics of paclitaxel and carboplatin in a dose-escalating and dose-sequencing study in patients with non-small-cell lung cancer. The European Cancer Centre

PURPOSE: To investigate the pharmacokinetics and pharmacodynamics of paclitaxel (P) and carboplatin (C) in a sequence-finding and dose-escalating study in untreated non-small-cell lung cancer (NSCLC) patients. PATIENTS AND METHODS: Fifty-five chemotherapy-naive patients with NSCLC were entered onto the pharmacokinetic part of a large phase I trial in which P was administered as a 3-hour infusion at dosages of 100 to 250 mg/m2, and C over 30 minutes at dosages of 300 to 400 mg/m2. Patients were randomized for the sequence of administration, first C followed by P or vice versa. Each patient received the alternate sequence during the second and subsequent courses. RESULTS: The most important hematologic toxicity encountered-was neutropenia. Hematologic toxicity was not dependent on the sequence in which P and C were administered, but there was cumulative neutropenia. Nonhematologic toxicities consisted mainly of vomiting, myalgia, and arthralgia. No sequence-dependent pharmacokinetic interactions for the P area under the concentration-time curve (P-AUC), maximal plasma concentration (P-Cmax), or time above a threshold concentration of 0.1 mumol/L (P-T > or = 0.1 mumol/L) were observed. However, there was a significant difference for the metabolite 6 alpha-hydroxypaclitaxel AUC (6OHP-AUC). Higher 6OHP-AUCs were observed when C was administered before P. The mean plasma ultrafiltrate AUC of C (CpUF-AUC) at the dosage of 300 mg/m2 for the sequence C-->P was 3.52 mg/mL.min (range, 1.94 to 5.83) and 3.62 mg/mL.min for the sequence P-->C (range, 1.91 to 5.01), which is not significantly different (P = .55). Of 45 assessable patients, there were five major responders (three complete responders and two partial responders). Four of five responses occurred at dosages above dose level 4 (P 175 mg/m2 + C 300 mg/m2). The median survival duration was best correlated with the P dose (4.8 months for doses < 175 mg/m2 v 7.9 months for doses > or = 175 mg/m2, P = .07; P-T > or = 0.1 mumol/L, 4.8 months for < 15 hours v 8.2 months for > or = 15 hours, P = .06). CONCLUSION: There was no pharmacokinetic-sequence interaction between C and P in this study. A clear dose-response relation with respect to response rate and survival was observed. The pharmacokinetic parameter P-T > or = 0.1 mumol/L was related to improved survival in this study.     

The effect of occupational exposure to metallic mercury on selected parameters of hemostasis

The group investigated comprised 60 workers under conditions of chronic exposure to metallic mercury vapours (mean exposure duration--9.3 yrs; mean age of subjects--38.5 yrs). The control group was composed of 24 non-exposed persons (mean age--39.9 yrs). The workers exposed were divided into three groups according to the air concentration of metallic mercury vapours at the workpost, group A--0.15-0.17 mg/m3, group B--0.03-0.08 mg/m3 and group C--0.02-0.03 mg/m3. The workers qualified for the study did not receive any medication containing acetylsalicylic acid derivatives, and did not consume alcoholic drinks for few days prior to the study. Persons with the diagnosis or the history of blood disorders, venous or arterial thrombosis as well as those with diabetes and hyperlipidaemia were excluded from the study. The haemostasis assessment was based on the results of laboratory tests, PLT, TBT, ACT, APTT, HTCT, INR and Fg, AT III, alpha 2 M, FDP, and FM concentrations. The comparison of the exposed and control groups revealed a statistically significant decrease in ACT and AT III concentrations. When particular groups under exposure were compared with one another and the controls, the increased INR and Fg concentrations were found in group A. Moreover, this group showed an increased platelet count, as well as decreased TBT and alpha 2 M concentrations. However, the differences between the groups were statistically insignificant. The results of the study indicated that chronic exposure to mercury may impair haemostasis and lead to hypercoagulability. The latter may result from the deficiency of natural coagulation inhibitors.     

Phase I study of raltitrexed (ZD-1694)

A multicenter cooperative phase I study of ZD-1694 (raltitrexed), a novel, folate-based thymidylate synthase (TS) inhibitor, was conducted with single and repeated doses in 30 patients with various malignant tumors. ZD-1694 was intravenously infused over 15 minutes. In the single-dose study, the initial dose was fixed at 1.0 mg/m2 (1n), and the dose was escalated stepwise up to 3.5 mg/m2 (3.5 n). Based on the results of the single-dose study, in the repeated-dose study, doses of 2.5 n and 3 n were infused every three weeks (3 weeks/one course). In principle, patients received 2 courses or more. Of the 29 eligible patients, 16 were in the single-dose study and 13 in the repeated-dose study. Adverse reactions were evaluated in all eligible patients. In the single-dose study, neutropenia, nausea/vomiting, diarrhea, and transaminase (GOT, GPT) increases, of grade 3 or higher, occurred at high doses of 3 n and 3.5 n. These were regarded as dose-limiting toxicities (DLT). DLT of grade 3 or higher were observed in 1 of 4 patients given 3 n and 2 of 4 patients given 3.5 n. These results suggested that the maximum tolerated dose (MTD) of ZD-1694 was 3.5 n (3.5 mg/m2). In the repeated-dose study, DLT of grade 3 or higher was observed in no more than one third of each dose group, 2 of the 6 patients given 2.5 n and 2 of the 7 patients given 3 n. These results suggested that 3 n (3.0 mg/m2), a dose nearer to MTD, was the recommended dose for the phase II study. Although transaminase increases were observed in all patients, in 12 of them the increase was grade 2 or lower and reversible. A pharmacokinetic investigation showed the mean elimination half life of ZD-1694 plasma concentration was 91.5 hours in the single-dose group and 119.1 hours in the repeated dose group. It was suggested that ZD-1694 is metabolized to polyglutamates after uptake and retained in the cells for a long duration. However, no accumulation was seen in plasma concentration of ZD-1694 following repeated doses at 3-weekly intervals. One PR was observed in a patient with colorectal cancer receiving 2.5 n in the repeated-dose study. Based on these results, the recommended dosage and administration for the phase II study of ZD-1694 was 3 n (3.0 mg/m2) intravenously infused over 15 minutes every 3 weeks.     

Environmental and biological control in a population exposed to isoflurane in the operating room

OBJECTIVE: To measure the level of occupational exposure to isoflurane in the operating room, and to determine the relation between isoflurane concentration in atmospheric and exhaled air. PATIENTS AND METHODS: One hundred seventy-eight samples were obtained from 60 male and female subjects who work in the operating room of our hospital. To monitor workplace exposure we used passive diffusion samplers. Biological monitoring (isoflurane in exhaled air) was accomplished with standard adsorption tubes to collect exhaled air samples. Gases were thermically separated and analyzed by gas chromatography. RESULTS: Atmospheric isoflurane concentrations ranged between 1.14 and 157.23 mg/m3 (geometric mean 16.23 mg/m3). Exhaled isoflurane concentrations ranged from 0.15 to 26.09 mg/m3 (geometric mean 2.85 mg/m3). Atmospheric and exhaled isoflurane concentrations were strongly related (r = 0.82; p < 0.0001). Linearity was determined by the following equation: log of exhaled isoflurane concentration = -0.69 + 0.95 log of atmospheric isoflurane concentration. CONCLUSIONS: The concentrations of isoflurane in atmospheric and exhaled air found in our study exceed the maximum levels for halogenated gases recommended by the National Institute for Occupational Safety and Health, although they do not exceed the levels stipulated by Swiss authorities. In order to adequately assess operating room antipollution measures, atmospheric and biologic monitoring of isoflurane and other inhaled anesthetic gas concentrations is necessary.     

新型拨料装置的开发与应用

为了解决烧结系统胶带运输机的扬尘及料形分配等问题,设计开发了新型拨料装置,该装置由普通型材焊接而成,刀头部分采用螺栓与拉杆支架相联接,拉杆部分采用铰链结构。该装置的应用保证了料形,避免出现跑料等工艺事故,岗位粉尘浓度由70mg/m^3下降到8mg/m^3,清理散料的工作量减少了2/3。     

莱钢H型钢生产线精轧机除尘系统设计与应用

莱钢型钢厂大H型钢生产线精轧机组设计安装气动洗气除尘系统,系统包括风机系统、烟尘捕集及管道系统、除尘器系统、电气控制系统、给排水系统、操作系统。系统投运后,粉尘浓度由55 mg/m3下降到6 mg/m3,现场环境得到明显改善。     

金渠金矿破碎车间除尘设备的改造及应用

选矿厂破碎车间普遍存在粉尘现象。介绍了金渠金矿破碎车间湿式除尘系统的设计、试运行及存在问题;提出了设备改造方案。改造运行效果表明,破碎车间操作岗位的粉尘浓度1mg／m^3,除尘系统排放的粉尘浓度80mg／m^3,达到了国家标准;除尘系统改造提高了除尘效率,改善了作业环境。     

Plasma renin activity in tachistin-stimulated hypercalcemia and under the effect of chlorazine

The aim of the present study was to elucidate the correlation between the Renin secretion and increased Plasma Calcium concentration and the role of Calmodulin in this process. Plasma Renin activity was determined radioimmunologically in 31 white rats, that were grouped as follows: group I - 7 controls loaded for 6 days perorally with 0.5 ml/200 g b.w. glycerin and injected i.m. for 6 days with 0.1 ml/200 g b.w. with 0.9% NaCl; group II - 8 rats, treated for 6 days with Tachistin 0.0025 mg/200 g b.w., dissolved in glycerin 0.5 ml/200 g b.w.; group III - 5 rats, treated with Tachistin 0.005 mg/200 g b.w. in the same manner; group IV - 5 rats injected i.m. with Chlorazin 0.5 mg/200 g b.w. for 6 days; group V - 6 rats, loaded with double dose Tachistin and with Chlorazin 0.5 mg/200 g b.w. for 6 days. Blood samples were taken intracardially on the seventh day from the beginning of the experiment and were analyzed with kits of Sorin-Biomedica-Italy. Our results suggest that the hypercalcemia induced by Tachistin caused a dose-dependent increase of PRA and Ca-Calmodulin complex is the dominant second messenger of Renin secretion.     

5-Fluorouracil (5-FU) continuous intravenous infusion compared with bolus administration. Final results of a randomised trial in metastatic colorectal cancer

The aim of this Phase III, balanced randomised trial was to compare continuous intravenous infusion (CVI) of 5-FU with bolus (B) administration for metastatic colorectal cancer (CRC). One hundred and fifty-five non-pretreated patients were randomised to receive CVI 5-FU at a dose of 750 mg/m2/day (d), 7 d every 21 d (n = 77), or bolus 5-FU 500 mg/m2/d x 5 d every 28 d (n = 78). Incremental dose escalation at 50 mg per step was recommended in the absence of toxicity. All the patients had measurable metastatic disease (M), particularly, liver and a good performance status (WHO grade 0-1). Dose intensity was significantly higher in CVI than in the bolus group: 1369 mg/m2/week versus 558 mg/m2/week (P = 0.0001). Grade II-IV stomatitis was more frequent in the CVI group (31% versus 9%; P < 0.0001) as was hand and foot syndrome (14% versus 3%; P < 0.001). Diarrhoea (22% versus 12%) and grade III granulocytopenia (2% versus 6%) were comparable. Responses were more frequent in the CVI (26%) than in the bolus group (13%) (P < 0.04); progression-free survival was higher for the CVI group (P = 0.04), but there was no statistical difference in overall survival (median: 10 months (m) compared to 9 m), and 1 year survival (SD) 42% (6%) versus 40% (6%). In the multivariate analysis, survival was better for patients with a good PS, well-differentiated adenocarcinomas and a primary tumour without serosal extension. In conclusion, with a higher dose intensity, CVI 5-FU improved tumour control, but not overall survival.     

Postoperative Tc-scintimetry in femoral neck fracture. A prospective study of 46 cases

This article presents panic diary results of a dose-response study with imipramine hydrochloride in panic disorder with agoraphobia patients. Analysis of variance revealed significant time effects on panic frequency and severity measures, but group x time interaction effects were present for the severity measures only. Results also provided evidence for a positive dose-response relationship with 20 percent of patients in the placebo group, 31 percent in the low-dose group (0.5 mg/kg/day), 54 percent in the medium-dose group (1.5 mg/kg/day), and 70 percent in the high-dose (3 mg/kg/day) group being free of recurrent or severe panic attacks at posttreatment. Further stratified and logistic regression analyses revealed a direct linear relationship between total plasma tricyclic concentration and response. These findings affirm the dose-dependent nature and the specificity of imipramine's antipanic effects.