Differential sensitivity of human nonpregnant and pregnant myometrium to calcitonin gene-related peptide

OBJECTIVES

Calcitonin gene-related peptide (CGRP) is a smooth muscle relaxant with potent vasodilating properties. To investigate its inhibitory effects on human myometrial contractions, we obtained excised human myometria from term pregnant, with and without spontaneous labor, and nonpregnant patients.

METHODS

Myometrial strips were mounted in tissue baths in which contractile activity was recorded. Spontaneously contracting tissues in vitro were exposed to increasing concentrations of CGRP (10(-11)-10(-7) mol/L). Tissues without spontaneous contractions were induced to contract with either oxytocin or KCl before being exposed to CGRP. The IC25 (CGRP concentration required to inhibit contractility by 25%) was used as comparison between groups.

RESULTS

Tissues with spontaneous or oxytocin-induced in vitro contractions responded equally to CGRP relaxation. Tissues induced to contract with KCl in vitro required approximately 2000 times more CGRP for equal relaxation. In tissues with spontaneous or oxytocin-induced in vitro contractions, those from pregnant unlabored patients were 60 times more sensitive to CGRP than those from pregnant labored or nonpregnant patients. The letter two groups responded equally to CGRP.

CONCLUSIONS

The sensitivity of myometrial tissues to CGRP relaxation in vitro is increased from the nonpregnant to the pregnant term state. This increased sensitivity is lost once patients develop spontaneous term labor. The relative ineffectiveness of CGRP in relaxing KCl-induced in vitro contractions probably reflects its known mechanism of action, namely the hyperpolarization of cell membrane potentials via activation of membrane potassium channels.

Cupid's bow contour of the vertebral body: evaluation of pathogenesis with bone densitometry and imaging-histopathologic correlation

PURPOSE

To investigate the Cupid's bow contour by means of bone densitometry and imaging-histopathologic correlation.

MATERIALS AND METHODS

Radiographs and histologic slices were obtained in 64 cadaveric thoracolumbar spines to assess the morphology, distribution, and histopathologic features of the Cupid's bow contour. Dual-energy x-ray absorptiometry and radiography were performed in the lumbar spine in 406 healthy subjects. Bone density and body height and weight were then related to the presence of the Cupid's bow contour. The Cupid's bow contour was compared with the fish vertebra of osteoporosis and Schmorl node.

RESULTS

No clinically important relationship was found between lumbar bone density, body height and weight, and prevalence of the Cupid's bow contour. Histologic examination showed thickened bone in the Cupid's bow end plate with annular fibers inserting into this region. In cadavers, the Cupid's bow contour occurred at multiple lumbar and thoracic levels, with the highest frequency in the lower lumbar spine. Lateral radiographs enabled better detection of the contour change.

CONCLUSION

The Cupid's bow deformity is a developmental phenomenon that is unrelated to osteopenia or mechanical stress on the spine.

Expanded version of PKSIM for pharmacokinetic simulations of both metabolite and parent drugs

We recently described a computer software package for pharmacokinetic simulations called PKSIM. The programs are useful for studying drugs that display either a one-, two-, or three-compartment body model with linear or nonlinear elimination following single or multiple dosing. The practicality of PKSIM owes to its user-friendliness and flexibility to study the impact of pharmacokinetic perturbations and dosage regimens on the drug's concentration-time profile on a real-time basis. The interactive nature of PKSIM allows the test variables to be easily changed after each simulation. High-resolution graphic capabilities also permit presentation of pharmacokinetic profile in various body compartments, either individually or collectively on a single graph. The capability of PKSIM was recently extended to include simulations of both parent drug and metabolite, which adds to the value of the package. The present paper describes in detail the functions of these new features and how they can be applied to better comprehend the pharmacokinetic interdependency between the parent drug and metabolite. In addition to the dose, dosing regimen and rate of drug absorption, influences on the kinetic profiles of parent drug and metabolite by other variables such as formation rate of the metabolite, tissue distribution, tissue redistribution, elimination rates and distribution volume of both entities can be studied with minimal efforts. These new features can be particularly helpful for researchers to study prodrugs and drugs that produce active or toxic metabolites, or better understand the basic concepts of metabolite kinetics.

No subacute thrombosis and femoral bleeding complications under full anticoagulation in 150 consecutive patients receiving non-heparin-coated intracoronary Palmaz-Schatz stents

Intracoronary stenting has been shown to have better immediate and long-term clinical outcomes and less restenosis than standard balloon angioplasty. However, the benefit was achieved at the cost of higher rates of coronary thrombosis, bleeding complications, the need for anticoagulation, and longer hospital stay. For the latter reasons there is a tendency to replace the anticoagulants by antiplatelet agents alone after stenting. However, we prospectively monitored 150 consecutive patients (133 men, 17 women, mean age 58.5 years) from two centers since February 1993. They all had coronary artery disease and underwent percutaneous implantation of non-heparin-coated Palmaz-Schatz coronary stents under a full but lower dose of anticoagulation. The femoral approach was used in all patients except one. In the 150 patients, 200 stents were implanted in 165 target arteries with 172 lesions. Stenting was performed without the guidance of intravascular ultrasonography; high-pressure poststenting inflation was used in only 17.3% of patients with less than optimal angiographic results. Coronary angiography was performed at baseline, immediately after the procedure, and after 6 months (mean 207 +/- 53.6 days SD) of stenting. The mean (+/-SD) coronary minimum luminal diameter increased from 0.52 0.31 mm to 3.13 +/- 0.42 mm immediately after stenting was performed and was 2.12 +/- 0.91 mm at 6 months. There was a 0% subacute thrombosis rate and a 0% femoral bleeding complication rate in the whole series. Only three (2%) major events occurred: one Q-wave myocardial infarction from closure of an angioplasty site distal to the stent on a very long lesion, one cerebrovascular accident, and one noncoronary-related death. The only patient who underwent the brachial approach had hematoma; otherwise no other minor event occurred. The mean hospital stay was 4.5 days in one of the two study centers. The long-term clinical follow-up rate was 97.3%. The mean (+/- SD) clinical follow-up period was 589 +/- 363 days. Clinical symptoms improved; the percentage of patients who had angina according to the Canadian Cardiovascular Society functional class II, III, and IV was 31.3%, 44.7%, and 4%, respectively, before stenting was performed and was reduced to 4.7%, 3.7%, and 0%, respectively at 6-month follow-up after stenting was performed. The 6-month angiographic restudy rate was 90.6%, and the restenosis rate was 18.3%. In contrast to other reported series, these results support the idea that with careful puncture technique and meticulous postoperative wound care, intracoronary stenting can be successfully performed with the patient under full anticoagulation without major risks of bleeding and femoral vascular complications. Furthermore with a full but comparatively lower dose of anticoagulation, subacute thrombotic complications can be reduced to 0% even with non-heparin-coated stents without the use of intravascular ultrasound guidance and without the use of adjunctive high-pressure poststenting inflation in most patients. The restenosis rate and long-term clinical outcomes remained very favorable.

A clinical study of 130 patients with biliary tract cancers and periampullary tumors

A retrospective review of 130 patients with peripheral-type cholangiocarcinomas (PTCC), hilar-type cholangiocarcinomas (HTCC), extrahepatic cholangiocarcinomas (EHCC), gallbladder cancers (GBCA), and periampullary cancers (PACA), seen at National Cheng Kung University Hospital and Tainan Municipal Hospital from June 1987 to July 1993 was performed. There were 47 (36%) HTCC, 32 (25%) PACA, 24 (19%) PTCC, 17 (13%) GBCA, and 10 (8%) EHCC patients. The distribution is completely different from that reported in western countries. These cancers mainly occur in elderly patients. HTCC and GBCA were predominantly noted in female patients. Biliary cancers in Taiwan were not related to liver fluke infestation, inflammatory bowel disease or hepatitis B virus infection. However, a close association with biliary lithiasis was found. The incidence of gallstones was 67, 39, 20, 29 and 19% for PTCC, HTCC, EHCC, GBCA and PACA, respectively. The most common presentation for PTCC and GBCA was abdominal pain, or jaundice for HTCC, EHCC and PACA. These symptoms correlate well with the location of the tumors. Among serum tumor markers, the elevation of CA19-9 was most frequent, occurring in 86% of the patients while CA125 and CEA occurred in 47% and 30% of the patients, respectively. During the course of disease, infection developed in 61% of the patients and was the main cause of death in 25%. Biliary tract infection and sepsis were the two leading manifestations and occurred in 49% and 32% of the patients, respectively. Overall survival was poor except in patients whose tumor could be completely resected.

Paravertebral muscles in disease of the cervical spine

OBJECTIVES

Cervical spine disorders are common in the older population. The paravertebral muscles are essential to the support and stabilisation of the cervical spine but have been little studied. The aim was to determine whether pathological changes develop in these muscles in patients with severe cervical spine disease, which, if present, might contribute to the pathogenesis and symptomatology of their disorder.

METHODS

Open biopsies of superficial and deep paravertebral muscles were obtained during the course of surgical procedures to alleviate cervical myelopathy. Most of these patients had cervical spondylosis or rheumatoid arthritis involving the cervical spine. The biopsies were compared with muscle obtained at necropsy from patients without a history of cervical spine or neuromuscular disorder.

RESULTS

Muscle from both the study and control groups showed a similar range and severity of abnormalities. In several patients, grouped fibre atrophy suggested chronic partial denervation. Most biopsies showed type 1 fibre predominance and selective type 2 fibre atrophy. Ragged red fibres were a frequent finding and electron microscopy disclosed accumulations of mitochondria, a small proportion of which contained rounded, or longitudinally oriented, single osmiophilic inclusions. Fibres containing core-like areas were also frequent. These pathological features were seen with increasing severity and frequency with increasing age.

CONCLUSIONS

The paravertebral cervical muscles develop pathological abnormalities with increasing age with both neurogenic and myopathic features, the pathogenesis of which is probably multifactorial. Such a muscle disorder would be expected to be accompanied by functional impairment which may contribute to the development and symptomatology of cervical spine disease with increasing age.

Spatial resolution of atrial pace mapping as determined by unipolar atrial pacing at adjacent sites

BACKGROUND

The purpose of this study was to examine the spatial resolution of unipolar atrial pace mapping by pacing at adjacent sites within the coronary sinus and the right atrium.

METHODS AND RESULTS

Unipolar pacing from each pole of a quadripolar catheter was performed in the coronary sinus (n = 29) and in the right atrium (n = 10). Pacing from the distal electrode was used to simulate the site of origin of an atrial tachycardia. These P waves were compared with the P waves generated by unipolar pacing from each of the three proximal electrodes. The P waves were analyzed for changes in amplitude, duration, and configuration. Pacing within the coronary sinus resulted in significant changes in amplitude and duration at distances of 17 and 21 mm from the distal pole, respectively. Similarly, pacing in the right atrium resulted in significant changes in amplitude and duration at distances of 17 and 32 mm from the distal pole, respectively. No significant changes in configuration were noted in the coronary sinus in any lead at packing sites < or = 32 mm from the distal pole. Configurational changes were noted in the right atrium at pacing sites 17 mm from the distal pole.

CONCLUSIONS

The spatial resolution of unipolar atrial pace mapping is approximately 17 mm. These findings indicate that mapping techniques that depend on the accurate discrimination of P-wave morphology, such as pace mapping or concealed entertainment, are likely to be imprecise when used in the atria.

Phase I and pharmacokinetic study of oral UFT, a combination of the 5-fluorouracil prodrug tegafur and uracil

UFT is an oral preparation combining the 5-fluorouracil (FU) prodrug tegafur (FT) and uracil (U) in a 1:4 ratio, which is commercially available in Japan for the treatment of breast and gastrointestinal cancers. We sought to determine the tolerance of daily oral UFT and to relate this tolerance to the pharmacokinetics of FT and/or the derived FU, while exploring the possibility of circadian FU kinetics contributing to the results. A 28-day schedule followed by 2 weeks rest was began at the initial level of 300 mg/m2/day administered either at 8 a.m. or at 6 p.m. At the following level, 400 mg/m2/day patients were randomly assigned to a split-dose administration or to the above single, timed dose administration. Intolerance to single dosing was clearly demonstrated, and only the split dosing was advanced to 500 mg/m2/day. When this level proved too toxic, 400 mg/m2 was studied further on a 7 a.m., 3 p.m., and 11 p.m. (every 8 h) schedule. Pharmacology was determined on selected patients. In the single dose administration, areas under the curves of FU were higher following p.m. dosing, although substantial interpatient variation was present. Toxicities (diarrhea and neutropenia) were more severe in patients receiving the drug in single daily doses. We conclude that the kinetics of FT are saturable, with disproportionate increases in area under the curve (and toxicities) as dose levels are increased. With divided dosing, tolerance improves. UFT at a dose of 400 mg/m2/day administered as three divided doses (every 8 h) is suitable for Phase II studies, although toxicity requiring cessation of drug administration prior to completion of 28-day cycles will occur in some patients.

Incidence of lead system malfunction detected during implantable defibrillator generator replacement

Implantable cardioverter-defibrillator (ICD) generator replacement due to a depleted battery is a frequently performed procedure. The frequency with which sensing and defibrillation system failures are identified during device replacement procedures has not been previously described. Therefore, the purpose of this study was to prospectively determine the frequency of lead system malfunction detected at the time of device replacement in 55 consecutive patients undergoing ICD generator replacement. The mean age of the patients was 63 +/- 10 years and 40 of them were men. Forty-nine patients had an epicardial lead system, and six patients had a nonthoracotomy lead system. Four [7%] of these 55 patients were noted to have previously undetected lead system failure, either sensing (n = 3) or defibrillation (n = 1), necessitating system revision. The lead systems that failed were 40 +/- 6 months old (33-49 months). In summary, during ICD generator replacement, previously undetected problems with sensing or defibrillation may be identified in approximately 10% of patients. Therefore, a comprehensive evaluation of the sensing and the defibrillation functions should be an essential component of the ICD generator replacement procedure.

Abdomino-pelvic hyperthermia and intraperitoneal carboplatin in epithelial ovarian cancer: feasibility, tolerance and pharmacology

PURPOSE

To investigate the feasibility, toxicity, and pharmacokinetics of intraperitoneal (i.p.) carboplatin (CB) with concomitant abdomino-pelvic hyperthermia (HT) in advanced ovarian cancer patients.

METHODS AND MATERIALS

Patients with residual disease mainly confined to the peritoneal cavity after platinum based chemotherapy received an initial course of i.p. CB for baseline pharmacokinetics followed by three cycles of i.p. CB with concomitant regional hyperthermia. The goal of HT was to achieve at least 45 min of intraperitoneal temperature > 42 degrees but < 50 degrees C while maintaining normal tissue temperatures < 43 degrees C and systemic body temperatures < 38 degrees C. No analgesic premedication was used. Thermometry was recorded by multisensor fiberoptic probes placed within the peritoneal cavity, bladder, vagina, and oral cavity.

RESULTS

Thirteen patients received a total of 31 sessions. Our intraperitoneal temperature goal could not be achieved because of patient intolerance. At best, we could maintain intraperitoneal temperatures > 40 degrees C, for more than 40 min in 7 of 31 sessions. The average values of thermal variables were T90 = 40 degrees C, TAVE = 41 degrees C, TMIN = 38.2 degrees C, and TMAX = 42.9 degrees C. The mean maximum systemic temperature was 38 degrees C. Acute thermal toxicities requiring early interruption of hyperthermia were systemic temperature exceeding 38 degrees C (11 of 31), abdominal pain or generalized distress (20 of 31), and vomiting (2 of 31). Hematological toxicities were not increased by hyperthermia. Pharmacokinetics were consistent with enhanced clearance of CB by HT. Lower radio frequencies (< 75 MHz) achieved better heat deposition in the peritoneal cavity than higher frequencies (> 75 MHz). Two of the 13 patients (a Stage III and a Stage IV patient) are alive with no evidence of disease at 40 and 43 months from treatment.

CONCLUSIONS

Intraperitoneal temperatures in the range of 40 degrees C maintained for approximately 40 min can be achieved within the described setting. The probability of successful induction of therapeutic intraperitoneal temperatures appears to be higher when frequencies below 75 MHz are used. Patients who are potentially platinum sensitive and have minimal residual disease could potentially benefit from the combined treatment under the conditions studied. However, this temperature-time range appears inadequate against platinum resistant disease, and/or bulky residual pelvic disease. Alternative approaches such as whole body hyperthermia and carboplatin are warranted to overcome some of the obstacles observed.

Drainage catheters: in vitro comparison of internal retention mechanisms

In five drainage catheters, internal retention mechanisms (locking pigtail [14 and 8 F], inflatable balloon [14 F], or wings [14 and 24 F]) were evaluated for resistance to and distortion from dislodgment. Catheters were inserted into simulated tissue, and weight was added until dislodgment occurred. Resistance to dislodgment increased when the mechanisms were locked; the locking pigtail supported the most weight. Distortion caused by dislodgment was minimal.

Prospective randomized comparison of anodal monophasic shocks versus biphasic cathodal shocks on defibrillation energy requirements

Biphasic shocks are believed to be superior to monophasic shocks. Monophasic anodal shocks, as opposed to cathodal shocks, are associated with improved defibrillation energy requirements (DERs). However, it is unclear how the DER of anodal monophasic shocks compare with conventional biphasic shocks. Therefore the purpose of this study was to prospectively compare the DER of an anodal monophasic shock with that of a cathodal biphasic shock. A transvenous defibrillation lead with distal and proximal shocking electrodes was used. The subjects of this study were 20 consecutive patients with a mean age of 64.2 +/- 10.5 years ( +/- SD) and a mean left ventricular ejection fraction of 0.36 +/- 0.18. Six had had cardiac arrest. The DER, defined as the lowest energy that converted ventricular fibrillation to sinus rhythm, was determined twice with a step-down protocol (25 J, 20 J, 15 J, 10 J, 5 J, 3 J, 1 J). If the DER was > or = 25 J, then a subcutaneous patch was deemed necessary for system implantation. In random order the DER was determined with a monophasic anodal shock (distal electrode positive) and then with a cathodal (first phase, distal electrode negative) biphasic shock. The mean DER with anodal monophasic shocks was 15.1 +/- 8.5 J compared with 13.6 +/- 8.1 J with cathodal biphasic shocks (p = 0.4). A DER > or = 25 J was present in three patients with the monophasic waveform and in three patients with the biphasic waveform (p = NS). In conclusion, the DER and frequency of subcutaneous patch use with an anodal monophasic waveform is comparable to that obtained with cathodal biphasic waveform.

Gas chromatographic-mass spectrometric assay for N-2-chloroethylaziridine, a volatile cytotoxic metabolite of cyclophosphamide, in rat plasma

A sensitive and specific method for the quantitative analysis of N-2-chloroethylaziridine (CEA), a volatile cytotoxic metabolite of cyclophosphamide, has been developed using gas chromatography-mass spectrometry and stable isotope dilution techniques. The high volatility problem of CEA during isolation procedure was overcome by the combined use of a deuterium-labeled analog as the internal standard and a Snyder column-concentrator assembly. The assay was found to be linear from 16.7 to 2667 ng/ml in rat plasma with a routine detection limit of 5 ng/ml. The within-run precision at 33, 333 and 1333 ng/ml (n = 6) was found to be 4.8, 4.9, and 6.1%, respectively. The between-run precision was 6.4% (n = 6). The dichloromethane extraction recoveries at 33, 333, and 1333 ng/ml were found to be 101, 98, and 91%, respectively (all at n = 6). However, the overall recovery through extraction and evaporation was only 18.3, 15.2, and 27.7% at 33, 333, and 1333 ng/ml levels, respectively. The analytical method was used to evaluate the generation of CEA from its precursors in sodium phosphate buffer, in cell culture media, and the degradation of CEA in these media. In pH 7.4, 0.067 M sodium phosphate buffer at 37 degrees C, both phosphoramide mustard (PM) and nornitrogen mustard (NNM) were degraded in an apparent first-order fashion with half-lives of 24.8 and 14.5 min, respectively. The generated CEA was rather stable in this buffer and degraded with a half-life of 20 h. It was found that 32% PM and 91% NNM were converted to CEA in pH 7.4, 0.067 M sodium phosphate buffer at 37 degrees C, respectively, and 41% PM was transformed into CEA in RPMI 1640 tissue culture media containing 10% FBS at 37 degrees C. The generated CEA was very stable in the culture media with a degradation half-life of 265 h.

Atrioventricular node properties in patients with accessory pathways

A study during the era of surgical ablation suggested that atrioventricular (AV) nodal conduction is faster in patients with accessory pathways than in controls. In the present study, AV nodal characteristics were studied in 30 patients who underwent radiofrequency ablation of an accessory pathway and compared to 23 control patients. Sinus cycle length, AH and HV intervals, AV block cycle length, ventriculoatrial (VA) block cycle length, AV nodal effective refractory period, and VA effective refractory periods were measured in control and postablation accessory pathway patients before and after autonomic blockade with 0.04 mg/kg of atropine and 0.2 mg/kg of propranolol. The mean sinus cycle length in the control and accessory pathway groups did not differ significantly at baseline (798 +/- 211 and 766 +/- 156 msec, respectively) or after autonomic blockade (654 +/- 98 and 649 +/- 108 msec, respectively). The mean AH interval in the accessory pathway group (77 +/- 15 msec) was significantly shorter than in the control group (91 +/- 22 msec; p < 0.05) at baseline; however, there was no difference after autonomic blockade. No other significant differences were observed between the accessory pathway and control groups. These results demonstrate that AV nodal properties of patients with accessory pathways are not significantly different from controls and suggest that previously reported differences may have been due to selection bias.

Use of isoproterenol during programmed ventricular stimulation in patients with coronary artery disease and nonsustained ventricular tachycardia

Twenty-three consecutive patients (20 men and 3 women) with coronary artery disease and nonsustained ventricular tachycardia (VT) in whom sustained VT was not inducible in a baseline electrophysiology test underwent repeated testing during isoproterenol infusion to determine the inducibility of sustained monomorphic VT. After the baseline study, each patient received a 2 to 4 microgram/min infusion of isoproterenol (mean 2.5 +/- 0.8 microgram/min). The sinus cycle length shortened by a mean of 29% +/- 9% and programmed stimulation was repeated. Nineteen patients had no inducible sustained, monomorphic VT, two patients had only inducible nonsustained VT, and two patients had ventricular fibrillation. Patients were followed up for 10 to 20 months (mean 14.4 +/- 2.9 months) and had no syncope, sustained monomorphic VT, or sudden death. Isoproterenol infusion during programmed stimulation in patients with coronary heart disease and nonsustained VT does not facilitate the induction of sustained monomorphic VT.

Evaluation and extraction of the Accufix atrial J lead

The Accufix (Telectronics Pacing Systems, Englewood, Colo.) atrial active fixation pacemaker lead has a preformed J stiff retention wire that can fracture and erode through the atrium. We screened 85 patients with digital fluoroscopy and detected 18 (21%) lead fractures. Fourteen (16%) leads were successfully extracted by percutaneous techniques. The mean time for extraction and placement of a new atrial lead was 109 +/- 53 min, and a lead > 1 year old but not in the presence of a fracture was associated with a significantly longer extraction time. There were two extraction complications. One patient had a fever following the extraction, and one patient had a focal sensory deficit 1 week after the extraction probably caused by a paradoxical embolus. Standard percutaneous extraction tools can be used for successful and safe removal of a fractured Accufix lead.

QT dispersion in nonsustained ventricular tachycardia and coronary artery disease

This study examines the relation between QT dispersion and the inducibility of ventricular tachycardia (VT) in 35 consecutive patients with coronary artery disease who underwent electrophysiologic testing for evaluation of nonsustained VT. The mean age of the patients was 66 +/- 9 years (+/- SD) and the mean left ventricular ejection fraction was 0.36 +/- 0.14. In 6 patients in whom sustained, monomorphic VT was inducible by programmed ventricular stimulation, QT dispersion was significantly greater than in the 29 patients in whom VT was not inducible (126 +/- 35 vs 67 +/- 25 ms, p < 0.001). All patients who had a QT dispersion > 120 ms had inducible sustained monomorphic VT, and no patient who had a QT dispersion < 90 ms had inducible VT. The patients who had inducible VT dis not differ significantly from those who did not with regard to age, gender, ejection fraction, RR interval, or mean QT. In conclusion, in patients with coronary artery disease who have nonsustained VT, inducibility of monomorphic VT is associated with an increase in QT dispersion. QT dispersion may be helpful in predicting which patients with nonsustained VT are and are not likely to have inducible VT by programmed stimulation.

Analysis of ifosfamide, 4-hydroxyifosfamide, N2-dechloroethylifosfamide, N3-dechloroethylifosfamide and iphosphoramide mustard in plasma by gas chromatography-mass spectrometry

A sensitive and specific method for the simultaneous quantitation of ifosfamide (IF), 4-hydroxylifosfamide (4-OHIF), N2-dechloroethylifosfamide (N2D), N3-dechloroethylifosfamide (N3D) and iphosphoramide mustard (IPM) has been developed using gas chromatography-mass spectrometry (GC-MS) with an ion-trap mass spectrometer. Deuterium labeled analogues for each of these analytes were synthesized as the internal standards. The labile 4-OHIF in plasma was first converted to the more stable cyanohydrin adducts before dichloromethane extraction. IPM was extracted by C18 reversed-phase resin. All analytes were converted to their silyl derivatives before GC-MS analysis. The sensitivity limits ranged from 0.1 to 0.5 microgram/ml when 100 microliters of plasma was used. This method was validated with within-run coefficients of variation less than 5% (n = 8) and between-run coefficients of variation less than 12% (n = 6). The method was applied to the determination of plasma levels of IF and metabolites in the rat.

Glutathione S-transferase M1 genotype affects aminobiphenyl-hemoglobin adduct levels in white, black and Asian smokers and nonsmokers

Cigarette smoking is the major cause of bladder cancer in men in the United States, and the arylamines contained in cigarettes smoke, including 4-amino-biphenyl (4-ABP), are believed to play an important role in the induction of bladder cancer among smokers. N-acetylation, which is catalyzed by the genetically controlled hepatic N-acetyltransferase enzyme displaying two phenotypes (slow versus rapid), is a detoxification pathway for arylamines with regard to bladder carcinogenesis. In Los Angeles, CA, non-Hispanic white (white), black, and Asian males have comparable smoking habits and yet dramatically different risks of bladder cancer (31 of 100,000 in whites, 16 of 100,000 in blacks, and 13 of 100,000 in Chinese and Japanese). Previously, we have demonstrated that the prevalence of slow acetylators (the high-risk phenotype) was highest in whites (54%), intermediate in blacks (34%), and lowest in Asians (14%). We also showed that mean 3- and 4-ABP hemoglobin adduct levels were significantly higher in cigarette smokers relative to nonsmokers, and that the level increased with increasing number of cigarettes smoke/day. Most importantly, slow acetylators consistently exhibited higher mean levels of ABP hemoglobin adducts relative to rapid acetylators, regardless of race and level of cigarette smoking. We assessed 151 residents of Los Angeles County (CA) who were either white, black, or Asian (Chinese or Japanese) and over the age of 30 years for their glutathione S-transferase M1 (GSTM1) genotype (null versus non-null), acetylator phenotype (slow versus rapid), levels of 3- and 4-ABP hemoglobin adducts, and current use of tobacco products. Whites (27%) had the highest prevalence of the highest risk profile (slow acetylator, GSTM1 null), followed by blacks (15%) and Asians (2.7%), and the difference was statistically significant (P = 0.006). Whites also had less than one-half the prevalence of the "protective" profile (rapid acetylator, GSTM1 non-null) relative to blacks and Asians (23 versus 57%; P = 0.0001). Regardless of race and level of cigarette smoking, mean levels of 3- and 4-ABP hemoglobin adducts were higher in subjects possessing the higher risk (GSTM1/acetylator profile. Mean level of 4-ABP hemoglobin adduct (adjusting for race, cigarette smoking, and acetylator phenotype) was significantly higher in subjects possessing the GSTM1-null versus GSTM1-non-null genotype (46.5 versus 36.0 pg/g Hb; P = 0.037). The comparable difference in mean levels of 3-ABP hemoglobin adduct was borderline significant (1.6 versus 1.1 pg/g Hb; P = 0.07). Thus, our results suggest that GSTM1 is involved in the detoxification of 3- and 4-ABP and may contribute to the racial variation in bladder cancer incidence among white, black, and Asian males in Los Angeles, CA.

Long-term follow-up of patients with advanced ovarian cancer treated in randomised clinical trials

The data from two prospective randomised phase III trials that were initiated by the West Midlands Ovarian Cancer Study Group (WMOCSG) in 1981 and 1986, recruiting 167 and 195 patients respectively, have been pooled and the survival patterns of the 362 patients treated for advanced epithelial ovarian cancer within clinical trials in the West Midlands over the 10 year period (1981-91) have been explored. All patients had histologically proven epithelial ovarian cancer and all had residual disease after primary surgery, with the majority having stage III/IV disease. The primary treatment for all patients was debulking surgery followed by platinum-based chemotherapy. Eligible patients were further randomised to undergo a second debulking operation. The main end point, survival, was assessed using Kaplan-Meier curves and the log-rank test. A Cox proportional hazards model identified performance status (P = 0.002), residual disease (P = 0.005) and albumin level (P = 0.04) as independent prognostic factors. A multivariate model to predict survival curves for patients with the best and worst prognoses was developed with predicted 5 year survival of 30% and 3% for those in the best and worst prognostic groups respectively. The identification of clinical interventions to improve outcome is an urgent matter since the prognosis for patients with advanced ovarian cancer remains poor.

The application of flow cytometric DNA analysis in detecting the presence of malignant cells in ovarian carcinoma peritoneal fluids

OBJECTIVE

To compare flow cytometric detection of malignant cells with standard cytological evaluation in patients with ovarian carcinoma.

SETTING

The City Hospital Trust, The Women's Hospital and CRC Trials Unit, Birmingham.

SUBJECTS

Forty-three patients with histologically proven ovarian carcinoma and positive cytology, and a control population of 20 patients undergoing surgery for benign gynaecological conditions.

METHODS

Prospective, blinded study examining ascitic fluid or peritoneal washings obtained at primary surgery by flow cytometric DNA analysis and cytological examination.

RESULTS

Flow cytometry detected aneuploid cells in 27/43 (63%) of malignant and 7/20 (35%) of benign fluid specimens. In malignant samples the mean aneuploid count was 38.5% (range 1-98%) with a mean S-phase fraction of 5.2% (range 0-33.9%). In benign specimens the mean aneuploid count was 30.4% (range 14.5-66.4%). Based on these results, the overall sensitivity of cytometric detection of malignant cells was 71.4%, specificity 65%, with a positive predictive value of 85.1%. False positivity was found mainly in patients with benign ovarian cysts. Further examination revealed four false negative and four false positive results, where the peritoneal fluid and ovarian tissue DNA ploidy status concurred. Assuming such results to be correct increased the sensitivity of the test to 88.5% and specificity to 85%.

CONCLUSIONS

Although flow cytometry can glean information beyond the capabilities of cytological assessment, using the premise that aneuploid cells alone indicate malignancy, it remains secondary to cytology in the detection of malignant cells in peritoneal fluids.

A novel multivariate approach for estimating the degree of similarity in bioavailability between two pharmaceutical products

Statistical assessment of bioavailability and bioequivalence of drug products is generally carried out with a univariate analysis by independently comparing each relevant parameter [such as, area under the drug concentration curve (AUC) and peak drug concentration (Cmax)] of the test and reference products. The assumption is made that AUC and Cmax are independent of each other. In reality, AUC, Cmax, and other pharmacokinetic parameters are dependent on each other. Therefore, a multivariate approach is theoretically superior. In this report, a novel multivariate approach to determine the bioavailability and bioequivalence of pharmaceutical products is described. The method determines the bivariate confidence ellipse (CE) between Cmax and AUC and the trivariate confidence ellipsoid (CED) among Cmax, AUC, and either Tmax or MRT for test and reference products. The similarity between the test and reference products can be assessed by the fraction of overlapping areas of CE and volumes of CED. The method and its comparison with conventional univariate analysis are demonstrated with data obtained from a bioequivalence study of ketoconazole tablets.