The use of imaging in preclinical drug development.

Molecular imaging tools, both equipment and agents, continue to improve and evolve, offering multimodality imaging with greater sensitivity and high-resolution of biological processes in real time. This review summarizes some of these recent developments in preclinical hardware, wetware and software, and their impact on drug development. The focus is on the advances in non-invasive small animal imaging such as positron emission tomography (PET), computed tomography (CT) and solid state detectors in single photon emission tomography (SPECT), which, when combined with labeled tracers serving as biomarkers and functional probes in vivo, are demonstrating the potential to accelerate our understanding of disease and help select drug candidates for development.

[Acute disseminated encephalomyelitis associated with mycoplasma pneumoniae infection]. / Encéphalomyélite aiguë disséminée associée au Mycoplasma pneumoniae.

A 20-year old man was hospitalized for acute urinary retention, headaches and mild fever. Neurological examination revealed a meningeal syndrome and a bilateral pyramidal syndrome of lower extremities with a C7 sensory level. The level of antibodies against Mycoplasma pneumoniae (Igm and IgG) suggested a recent unrecognized infection. Cerebral and medullar MRI showed T2-hyperintense lesions in the right thalamus and at the level of C1-C2 and C6. Evoked potentials were normal but EEG showed some bilateral theta waves. The cerebrospinal fluid analysis demonstrated 170 white cells/mm3 with 66% lymphocytes and proteins at 73 mg/dl. A few weeks after treatment with intravenous immunoglobulins at 0.4 g/kg/day for 5 days, the patient showed complete clinical recovery. MRI and urinary flowrate normalized after nine weeks. The authors are discussing the probable diagnosis of acute disseminated encephalomyelitis occurring after a mycoplasma unrecognized infection.

Intraoperative detection of cell injury and cell death with an 800 nm near-infrared fluorescent annexin V derivative.

The intraoperative detection of cell injury and cell death is fundamental to human surgeries such as organ transplantation and resection. Because of low autofluorescence background and relatively high tissue penetration, invisible light in the 800 nm region provides sensitive detection of disease pathology without changing the appearance of the surgical field. In order to provide surgeons with real-time intraoperative detection of cell injury and death after ischemia/reperfusion (I/R), we have developed a bioactive derivative of human annexin V (annexin800), which fluoresces at 800 nm. Total fluorescence yield, as a function of bioactivity, was optimized in vitro, and final performance was assessed in vivo. In liver, intestine and heart animal models of I/R, an optimal signal to background ratio was obtained 30 min after intravenous injection of annexin800, and histology confirmed concordance between planar reflectance images and actual deep tissue injury. In summary, annexin800 permits sensitive, real-time detection of cell injury and cell death after I/R in the intraoperative setting, and can be used during a variety of surgeries for rapid assessment of tissue and organ status.

Ectopic pregnancy within a rudimentary horn in a case of unicornuate uterus.

We report the MRI features of two cases of unicornuate uterus and occluded rudimentary horn. In one patient pregnancy had occurred in the occluded horn, prompting to urgent resection. The second patient illustrates more conventional findings in occluded rudimentary horn. In both cases MRI was able to correctly characterise the nature of the developmental anomaly. Furthermore, on the basis of signal intensities, differentiation between distended lumen due to blood accumulation and amniotic sac in the case of pregnancy could be made. Because of its high accuracy in determining the type of anomaly present, the lack of ionizing radiation, and the ability to evaluate, with the exception of the fallopian tubes, the entire genitourinary tract, MR imaging is essential and plays a key role in the evaluation of women who are consulting for infertility.

Discordant prenatal diagnosis of congenital toxoplasmosis in a dizygotic pregnancy.

Prenatal diagnosis of toxoplasmosis gondii in twin pregnancies has been described twice. In both cases they were accomplished by prenatal blood sampling of the foetuses. We report the first prenatal diagnosis with a discordant result in a dizygotic pregnancy. One of the foetuses died in utero and the other was born unaffected at term.

Dimeric inhibin serum values as markers of ovarian activity in pill-free intervals.

Levels of inhibin A and B as well as other hormones in serum samples obtained during the pill-free interval in women taking combined oral contraceptives (OC) were measured to asses the extent of ovarian activity during that period. Type of pill and day of pill-free interval were recorded during routine gynecologic check-ups, if patients were in the pill-free period and had taken their pills regularly in the previous cycle. In addition to inhibin A and B, serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone were also quantified. Inhibin B levels rise significantly in parallel with rising levels of FSH, LH, and E2. Progesterone levels were completely suppressed and inhibin A levels rose slightly but insignificantly. Inhibins are sensitive biochemical markers of ovarian activity in pill-free intervals.

PIP: Serum values of dimeric inhibin A and B were measured to assess the restoration of pituitary and ovarian activity during the pill-free interval in women taking combined oral contraceptives. 175 healthy women 18-35 years of age from five areas in Belgium were enrolled and monitored during routine gynecologic examinations. During the 7 day pill-free interval, inhibin B levels rose significantly in parallel with rising levels of follicle-stimulating hormone, luteinizing hormone, and estradiol. Progesterone levels were completely suppressed. Inhibin A levels rose slightly but insignificantly, reflecting an absence of development of preovulatory follicles. These findings indicate that inhibins are sensitive biochemical markers of ovarian activity in pill-free intervals. Inhibin B appears to be predominantly a product of the cohort of developing primary and subsequent early antral follicles, while inhibin A secretion is more indicative of dominant follicular and corpus luteum function.

Preparation, characterization, and biological evaluation of technetium(V) and rhenium(V) complexes of novel heterocyclic tetradentate N3S ligands.

Various tetradentate N3S ligands which contain pyridyl, morpholino, or imidazolyl moieties were prepared and labeled with technetium and rhenium. Metal complexation of the ligands occurred efficiently over the pH range from 2 to 11. Ligands possessing the S-THP (tetrahydropyranyl)-protected mercapto group labeled efficiently even under alkaline conditions, and among the three types of heterocyclic metal complexes, a marked difference in stability was observed; rhenium complexes decomposed to ReO4 whereas technetium complexes decomposed to TcO2/TcO4. In general, imidazolyl complexes of both technetium and rhenium were very stable in saline; less than 10% decomposition after 24 h. The technetium histidyl complex and technetium pyridyl complex were quite stable even under cysteine challenge; less than 10% decomposition after 24 h. The rhenium and technetium morpholino complexes were very unstable; greater than 10% decomposition after only 1 h in saline and greater than 25% decomposition in 1 h under cysteine challenge. Profound pharmacokinetic differences among these metal complexes were also observed in rat biodistribution studies. The neutral pyridyl complexes exhibited high blood and liver uptake and slow clearance from these tissues. The replacement of a hydroxyl group by a carboxyl group, which resulted in an anionic complex at physiological pH, resulted in a dramatic decrease in blood and liver uptake. The neutral imidazolyl complex exhibited marked reduction in blood uptake and much faster clearance from blood and liver compared to the neutral pyridyl complex. Finally, the anionic histidyl complex, which contains both the imidazolyl and carboxyl groups, had the most favorable pharmacokinetic properties in that it exhibited very low blood, liver, and kidney uptakes and a rapid clearance from the body via the renal system. The combination of the high stability and favorable pharmacokinetic properties of the imidazolyl complexes should render them useful for targeted delivery of the medically important isotopes.

Development of endosalpingoblastosis and tuboperitoneal fistulas following tubal sterilization: relation with uterine adenomyosis.

A total of 25 consecutive patients who had undergone a tubal sterilization and who were referred for a hysterectomy, were examined by a peroperative methylene blue test of the tubal stumps, and extensive microscopic examination of the uterine wall, cornua and tubal stumps. Eighteen patients had been sterilized by electrocoagulation and 7 by mechanical methods (clips or rings). Tubo- or uteroperitoneal fistulas and endosalpingoblastosis were only observed in the group of patients sterilized by electrocoagulation. The development of tubo- or uteroperitoneal fistulas was correlated with the presence of endosalpingoblastosis and of uterine adenomyosis (P = 0.002 and P = 0.038, respectively). All patients with bilateral fistulas had bilateral endosalpingoblastosis and the only patient with a unilateral fistula had endosalpingoblastosis on the same side. The development of endosalpingoblastosis in patients sterilized by electrocoagulation was correlated with the presence of uterine adenomyosis (P = 0.008). In the same group of patients, a correlation between the length of the proximal tubal stump and the development of utero- or tuboperitoneal fistulas was observed (Wilcoxon test, P = 0.033). Two patients developed an ectopic pregnancy following sterilization. Both patients were sterilized by electrocoagulation, and had endosalpingoblastosis and bilateral fistulas. Our results suggest that the presence of uterine adenomyosis might predispose to the development of endosalpingoblastosis when performing tubal electrocoagulation close to the uterine cornum. We therefore suggest that when performing tubal coagulation, the intact proximal stump should be at least 2 cm.

[Long-latency auditory evoked responses in Parkinson disease and in parkinsonism induced by neuroleptics]. / Potentiels évoqués auditifs de longue latence (AEP) dans la maladie de Parkinson et le parkinsonisme induit par neuroleptiques.

The amplitude and latency of the N100 wave (auditory evoked potentials) were studied in 28 normals, 85 parkinsonians, 24 extrapyramidal syndromes induced by neuroleptics and 12 neurological control patients. The latency decreases as an inverse function of the intensity of stimulation in normals, controls, treated parkinsonians and in extrapyramidal syndrome induced by neuroleptics. Untreated parkinsonians do not show an evident relation between the latency and the stimulation level. The amplitude of the N100 decreases when neuroleptic induced parkinsonism improves.

Clinical experience with rhenium-186-labeled monoclonal antibodies for radioimmunotherapy: results of phase I trials.

Rhenium is a radionuclide with physical and chemical properties suitable for radioimmunotherapy. Two Phase I trials were carried out using 186Re-labeled murine monoclonal antibodies. Patients with refractory metastatic epithelial carcinoma received single doses of either 186Re-labeled intact NR-LU-10, a pancarcinoma antibody, 25-120 mCi/m2 (n = 15) or 186Re-labeled F(ab')2 fragment of NR-CO-02, an anti-CEA variant antibody, 25-200 mCi/m2 (n = 31). Prior to radioimmunotherapy, tumor localization of antibody was confirmed by 99mTc-labeled NR-LU-10 Fab or 99mTc-labeled NR-CO-02 F(ab')2 imaging. Dose-limiting myelosuppression was observed at 120 mCi/m2 following 186Re-NR-LU-10 intact antibody and at 150 mCi/m2 following NR-CO-02 F(ab')2 fragment in heavily pretreated patients. In patients with minimal prior therapy, a maximum tolerated dose for NR-CO-02 F(ab')2 was not reached by 200 mCi/m2. Non-marrow toxicity was minimal. Human anti-mouse antibody developed in all patients receiving intact NR-LU-10, and in 86% patients receiving F(ab')2 NR-CO-02. One patient treated with 186Re NR-CO-02 achieved a partial response. We conclude that 186Re-labeled antibody can be safely administered with significant toxicity limited to marrow.

Comparisons of the efficacy of 186Re- and 131I-labeled antibody in multicell spheroids.

Several radionuclides are being studied for use in radioimmunotherapy. Although 131I has been used most widely, there are several disadvantages to it including its large gamma-ray component, its rather long half-life, and its modest beta-particle energy. However, the beta-particle energy can be an advantage in very small tumors (less than 1-2 mm). 186Re has several potential advantages over 131I but it has never been directly compared with it experimentally. Dosimetry modeling predicted that 186Re would have a dose advantage over 131I at large tumor sizes but for tumors as small as 1 mm diameter, this advantage would be lost. In order to confirm these predictions experimentally, this study compared the relative efficacy of a pancarcinoma antibody, NR-LU-10 labeled with 186Re or 131I in 0.8-1.0 mm diameter LS174T human colon adenocarcinoma multicell spheroids. Spheroids were incubated for 90 hr at 37 degrees C and evaluated with clonogenic assay, autoradiography, and histology. When corrected for cumulative activity bound, both radionuclides were equally effective. Autoradiography demonstrated poor penetration of radionuclide into the depths of the spheroids. Because 186Re has a theoretical dose advantage in larger tumors and because it has been shown to be equivalent to 131I in tumors as small as 1 mm diameter, it may be superior to 131I in most clinical situations. However, in the treatment of micrometastases of less than 1 mm diameter, theoretical dosimetry modeling predicts that 131I or radionuclides with similar beta particle energies should be more effective.

Unusual complication after pelvic surgery: unilateral lower limb crush syndrome and bilateral common peroneal nerve paralysis.

We present a patient who developed a right anterior leg compartment syndrome and bilateral common peroneal nerve paralysis following radical hysterectomy in the lithotomy position. We describe the physiopathology of the syndrome, its various etiologies, the treatment, and prevention of this complication.

Antenatal fetal death in twin pregnancies: a dangerous condition mainly for the surviving co-twin; a report of four cases.

The outcome of four twin pregnancies with fetal death of one twin during the late second and the third trimester is described. A review of the complications occurring after antepartal fetal death of one twin is presented. A management plan for this rare complication of pregnancy is established.

186Re radioimmunotherapy of small cell lung carcinoma xenografts in nude mice.

A 186Re-labeled monoclonal antibody (MAb), NR-LU-10, was used for the radioimmunotherapy of a subcutaneous human small cell lung carcinoma xenograft, SHT-1, in nude mice. Biodistribution with specific and irrelevant labeled MAb demonstrated peak tumor uptake of 8% and 3% of the injected dose/g at 2 days, respectively. Dosimetry analysis predicted tumor:whole-body radiation-absorbed dose ratios of 2.43:1 for NR-LU-10 and 0.62:1 for irrelevant MAb. Single-dose toxicity screening estimated a 50% lethal dose within 30 days of 600 microCi (880 cGy of whole-body radiation). As anticipated, a multiple-dose regimen of 490 microCi in four doses over 10 days (720 cGy of whole-body radiation, eight of eight surviving greater than 30 days) was less toxic than a single bolus dose of 430 microCi (644 cGy of whole-body radiation), six of eight surviving greater than 30 days). A multidose radioimmunotherapy regimen was initiated in nude mice bearing 66-mm3 tumors (total dose, 500 to 600 microCi). Complete remissions (greater than 140 days) were achieved in three of 16 mice, and the remainder showed a mean tumor growth delay of 53 days. Matched doses with irrelevant MAb produced one remission, one treatment-related death, and a mean growth delay of only 20 days in six of eight mice. Thus, in this nonoptimal radioimmunotherapy model, significant antitumor responses were observed using a mildly toxic multiple dosing regimen.

Female sterilization failure after bipolar electrocoagulation: a 6 year retrospective study.

A 6 year retrospective study was conducted from January 1983 till December 1988. During this period there were 13,014 births, 1,776 registered spontaneous abortions and 200 tubal pregnancies. 1,437 sterilizations were performed in the same period via bipolar electrocoagulation. 11.5% of the ectopic pregnancies were in patients who had previously undergone a tubal sterilization. The failure ratio following bipolar coagulation was 1.18%, and all failures were extra-uterine pregnancies, with an average interval between sterilization and ectopic pregnancy of 28.8 months. This reflects the importance of previous sterilizations as an etiologic agent in ectopic gestations. We will discuss the possible etiological factors for our sterilization failures and how these failures can be avoided or minimized. Also diagnostic difficulties and management of an extra-uterine pregnancy (EUP) following sterilization will be presented.

PIP: A 6-year retrospective study was conducted from January 1983-december 1988. During this time, there were 13,014 births, 1776 registered spontaneous abortions, and 200 tubal pregnancies. 1437 sterilizations were performed in the same period via bipolar electrocoagulation. 11.5% of the ectopic pregnancies were inpatients who had previously undergone a tubal sterilization. The failure ratio following bipolar coagulation was 1.18% and all failures were extrauterine pregnancies, with an average interval between sterilization and ectopic pregnancy of 28.8 months. This reflects the importance of previous sterilizations as a contributing factor in ectopic gestations. The authors discuss the possible etiological factors involved in these sterilization failures and how these could by avoided or minimized. Also, diagnostic difficulties and management of an extrauterine pregnancy (EUP) following sterilizations presented.

Considerations for imaging Re-188 and Re-186 isotopes.

Re-186 and Re-188 have been suggested for radioimmunotherapy because of their energetic beta particles, imageable gamma photons, and chemical properties similar to technetium. Because of this potential, these isotopes were evaluated before in vivo imaging was attempted. It was found that low-abundance, high-energy gamma photons present in these rhenium isotopes require a medium-energy collimator to yield optimal image resolution and count rate, which are critical factors in the performance of preliminary imaging studies on patients for antibody imaging and therapy.