Binding of 125I-iodovinyltetrabenazine to CNS vesicular monoamine transport sites.

Binding characteristics of a novel radioiodinated tetrabenazine (TBZ) analog (iodovinyltetrabenazine; 125I-TBZ-Fraction I) were evaluated. In rat striatal homogenates, 125I-TBZ-I displayed a pharmacological profile consistent with specific binding to vesicular monoamine transport (VMAT) sites. In vitro autoradiographic studies using rat brain sections further demonstrated that 125I-TBZ-I labeled the regions rich in VMAT sites, and it may be a useful marker for these sites. This novel radioiodinated ligand, with high specific activity and high binding affinity, may provide a powerful tool for the in vitro assessment of neuronal loss in various neurodegenerative diseases.

Technetium-99m N,N'-bis(2-mercapto-2-methylpropyl)-2-aminobenzylamine: technetium-99m complexes of a novel bis(aminoethanethiol) ligand.

A new N2S2 ligand system, N,N'-bis(2-mercapto-2-methylpropyl)-2- aminobenzylamine, U-BAT, 1, containing uneven amine groups (two amine groups with different pKa values) for complexing [TcVO]3+, was prepared. The reaction of this novel ligand with [99mTc]pertechnetate, in the presence of stannous tartrate as the reducing agent, produces the neutral and lipid-soluble [99mTc]TcVO(U-BAT), TcS2C15H23N2O, 2. However, when the same reaction was carried out at a higher pH, 9-10, and with 30 min of heating (100 degrees C), a second neutral but more lipid-soluble complex, [99mTc]TcVO(OU-BAT), TcS2C15H21N2O, 3, was isolated. The X-ray crystallography data of the 99Tc complexes show square pyramidal coordination with N2S2 as the base and the Tc = O in the apical position. Compound 3 can be derived from 2 by an oxidation of the ligand to form an imine. After iv injection into rats, the neutral and lipid-soluble technetium-99m complexes showed significant brain uptake, 1.54 and 1.07% dose/organ at 2 min for [99mTc]TcVO(U-BAT) and TcVO(OU-BAT), respectively. The novel Tc chemistry of this new ligand system may provide a useful foundation for designing Tc complexes with a built-in redox mechanism.

Localization of IBF as a D-2 dopamine receptor imaging agent in nonhuman primates.

Preliminary study of iodine-123 labeled IBF, (S)-5-iodo-7-N-[(1-ethyl-2-pyrrolidinyl)methyl] carboxamido-2, 3-dihydrobenzofuran, has demonstrated the potential of using this agent to evaluate the status of the CNS D-2 dopamine receptor in humans. To further characterize this ligand and evaluate single-photon emission tomography (SPET) quantitation, a detailed biodistribution study in monkeys (Macaca fascicularis) with 123I- and 125I-IBF was performed. The dual tracer was simultaneously injected for in vivo imaging, bio-distribution, and ex vivo autoradiography in the same monkey. After the injection, SPET data (10 min/frame x 15) were collected with a triple-head gamma camera. Dynamic imaging data indicated that IBF localized in basal ganglia (BG) with a half life of 90-120 min. Other regions, i.e., cerebellum (CB) and cortex (CX), showed very low uptake. At 2.2 h after the injection, the monkey was sacrificed. Organ distribution data indicated that, as expected, there was a significant uptake in basal ganglia (0.029% ID/g), and the BG/CB and BG/CX ratios were 17.8 and 14.2 respectively. Lower ratios were obtained from SPET image analysis (BG/CB = 3.5 at 2.5 h). The eye uptake was observed with SPET, but was only quantified on autoradiograms with significant uptake (0.017% ID/g). Autoradiography of the eye demonstrated that predominant uptake was localized in the ciliary body and the choroid. The selective retention and high BG/CB ratio of 123I-IBF make it a useful agent for in vivo D-2 dopamine receptor imaging with SPET.

Characterization of radioiodinated TISCH: a high-affinity and selective ligand for mapping CNS D1 dopamine receptor.

In developing CNS D1 dopamine receptor-imaging agents with improved specificity and longer brain retention, an iodinated D1 ligand was synthesized. In vitro and in vivo radiolabeling studies of a new iodinated benzazepine, TISCH [7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1H-3- benzazepine], an analog of SCH 23390 (7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepin e), were investigated. After an intravenous injection, the R(+) isomer of TISCH showed high brain uptake in rats (2.20 and 0.57% dose per whole brain at 2 and 60 min, respectively). The striatum/cerebellum ratio increased progressively with time (12 at 60 min). Ex vivo autoradiography of rat brain sections, after intravenous injection of R(+)-[125I]TISCH, displayed the highest uptake in striatum and substantia nigra, regions known to have a high concentration of D1 receptors, whereas the S(-) isomer displayed no specific uptake. Furthermore, the specific uptake can be blocked by pretreatment with SCH 23390. In vitro binding studies using the rat striatum tissue preparation showed high specific and low nonspecific bindings (KD = 0.21 +/- 0.03 nM). The rank order of potency exhibiting high specificity to the D1 receptor was SCH 23390 greater than (+/-)-TISCH greater than (+)-butaclamol = (+/-)-FISCH [7-chloro-8-hydroxy-1-(4'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1 H-3-benzazepine] much greater than WB4101 = spiperone greater than dopamine, serotonin, (+/-)-propranolol, and naloxone. Imaging studies in a monkey with the resolved isomer, R(+)-[123I]TISCH, demonstrated a high uptake in the basal ganglia and prolonged retention. The preliminary data suggest that R(+)-TISCH is selective for the CNS D1 receptor and is potentially useful for in vivo and in vitro pharmacological studies. When labeled with iodine-123, it may be suitable for noninvasive imaging in humans.

Synthesis and resolution of (+-)-7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro- 1H-3- benzazepine (TISCH): a high affinity and selective iodinated ligand for CNS D1 dopamine receptor.

The synthesis and resolution of (+-)-7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1 H-3- benzazepine, (+/-)-TISCH (8) has been achieved by resolution of intermediate 4, the O-methoxyl, 3'-bromo derivative, as the diastereomeric camphor sulfonate salt. The final products, R-(+)-8 and S-(-)-8, were prepared by treatment of R-(+)- or S-(-)-7, the 3'-tributyltin intermediates, with iodine in chloroform, followed by O-demethylation. By using HPLC with a chiral column, the optical purity (greater than 99%) of the intermediates and the final compounds was determined. Radioiodination was achieved by an iodo-destannylation reaction with sodium [125I]iodide and hydrogen peroxide. As expected, the R-(+)-[125I]-8 (the active isomer) displayed high affinity and selectivity to the CNS D-1 receptor in rat striatum tissue preparation (Kd = 0.205 nM). The rank order of potency was as follows: SCH-23390 (1a) greater than (+/-)-8 greater than (+)-butaclamol greater than spiperone, WB4101 greater than dopamine, 5-HT. After an iv injection, the R-(+)-[125I]-8 penetrated the blood-brain barrier with ease and displayed specific regional distribution corresponding to the D-1 receptor density, while the S-(-)-[125I]-8 showed no specific uptake. The data suggest that the ligand may be useful as a pharmacological tool for characterizing the D-1 dopamine receptor. When labeled with I-123, this ligand is a potential agent for in vivo imaging of CNS D-1 dopamine receptor.

A kit formulation for preparation of iodine-123-IBZM: a new CNS D-2 dopamine receptor imaging agent.

A method for the preparation of iodine-123IBZM, a central nervous system D-2 imaging agent, is reported. By using a rapid filtration technique to remove the unreacted iodide, the preparation can be completed in less than 20 min (overall yield greater than 60%). The product, with high purity (greater than or equal to 95%) and specific activity, is suitable for human use.

The validation of the Billings ovulation method by laboratory research and field trials.

PIP: Fertility and the mechanism of ovulation is complex. The processes of fertilization and ovulation are described in this report. Information includes a description of the natural indicators of fertility and infertility, the cervical mucus pattern, and the Guidelines for the Billings Ovulation Method. The ovarian monitor which provides for the measurement of ovarian hormones (estrone glucuronide (EIG) and pregnanediol glucuronide (PdG) in a timed specimen of urine is also described. The cervical mucus pattern method measures ovarian hormones and fertility. No more than 2% of women who have been taught the Ovulation Method and performed the charting would need to use the Ovarian Monitor. It is commonly used to assure that the women's observations and interpretations are correct when there is a strong desire to either achieve or postpone pregnancy. For research, the monitor is useful in accurately measuring the timing of ovulation within the phase of potential fertility during the cycle and the changing probabilities of conception on days within the fertile period. The limits of the fertilizing life span of sperm can be measured as well as the factors which influence this life span. The day of maximum fertility, the correlation of the mucus pattern with fertility and time of ovulation, and assessment of conception cycles are measurable. Diagnostic information can be gleaned which will help to explain bleeding patterns, particularly around menopause, where fluctuating ovarian hormonal levels influence unexplained bleeding patterns. The Monitor can be useful as a test for pregnancy in measurement of high PdG and E1G levels. Four phases are identified for interpreting the ovulatory cycle: 1) the E1G and PdG levels are declining during the beginning of menstruation to reach a constant level (20-60 nmol/24 hours and .9 - 3.3 mcmol/24 hours); 2) rising E1G values and low PdG values and changing mucus pattern of the preovulatory cycle; 3) the ovulatory phase of peak E1G values (150-450 nmol/24 hours) followed by a distinct fall and the beginning of a rise in PdG values and the Peak of the mucus pattern; and 4) the luteal phase of rising PdG (9-36 mcmol/24 hours), and rising E1G values (100-400 nmol/24 hours) to maximum, and then falling before menstruation.^ieng

A new myocardial imaging agent: synthesis, characterization, and biodistribution of gallium-68-BAT-TECH.

In order to develop a new myocardial perfusion agent for positron emission tomography (PET), a new lipid-soluble gallium complex was evaluated. Synthesis, radiolabeling, characterization, and biodistribution of a unique gallium complex, [67Ga]BAT-TECH (bis-aminoethanethiol-tetraethyl-cyclohexyl), are described. The complex formation between Ga+3 and BAT-TECH ligand is simple, rapid, and of high yield (greater than or equal to 95%). This process is amenable to kit formulation. The complex has a net charge of +1 and a Ga/ligand ratio of 1:1. Biodistribution in rats shows high uptake in the heart as well as in the liver. When [68Ga] BAT-TECH was injected into a monkey, the heart and liver are clearly delineated by PET imaging, suggesting that this complex may be a possible tracer for myocardial perfusion imaging.

Synthesis and biodistribution of 99mTc-labeled piperidinyl bis(aminoethanethiol) complexes: potential brain perfusion imaging agents for single photon emission computed tomography.

In developing clinically useful 99mTc-labeled radiopharmaceuticals for the evaluation of regional cerebral perfusion with single photon emission computed tomography (SPECT), a number of substituted alkyl(aryl)piperidinyl bis(aminoethanethiol) ligands for chelating [99mTc]TcO(III) were synthesized. Each ligand forms two diastereomers, syn and anti, after reacting with a racemic mixture of the ligand. The diastereomers were separated by high-pressure liquid chromatography. In biodistribution studies conducted in rats, the diastereomers exhibit widely disparate brain uptake values; however, this disparity seems to diminish as the steric bulk of the substituent at the C-4 position of the piperidinyl moiety increases. Furthermore, all the complexes evaluated failed to show a prolonged retention in the rat brain, suggesting that further structural modification may be necessary to obtain clinically useful complexes from this class of compounds.

Preparation and biodistribution of [125I]IBZP: a potential CNS D-1 dopamine receptor imaging agent.

Carrier free [125I]IBZP, R-(+)-8-[125I] iodo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepine-7-ol), was prepared from the corresponding uniodinated compound by an oxidative iodination reaction with chloramine-T and sodium [125I]iodide. After purification by column chromatography the desired uptake was obtained with a high purity (greater than 95%). The agent showed good localization in brain after i.v. injection in rats, with an uptake of 2.7, 1.2 and 0.8% dose/organ at 2, 15 and 30 min post injection, respectively. The regional distribution in rat brain, as measured by in vivo autoradiography, displayed a high uptake in the caudate putamen, accumbens nucleus and substantia nigra, regions known to have a high concentration D-1 dopamine receptors. The uptake ratio of striatum/cerebellum increased with time; at 30 s and 2 h after injection the ratio was 1.1 and 5.3, respectively. The specific uptake in the D-1 dopamine receptor regions can be blocked by pretreatment with SCH-23390, a selective D-1 dopamine receptor antagonist (SCH-23390). The corresponding iodine-123 (t1/2 = 13 h, gamma energy 159 keV) labeled agent may be suitable for SPECT imaging of CNS D-1 dopamine receptors.

Comparison of in vivo D-2 dopamine receptor binding of IBZM and NMSP in rat brain.

In vivo biodistribution of S- and R-isomers of [125I]IBZM in rats showed a significant initial brain uptake (3.20 and 2.67% dose/organ at 2 min, respectively). The wash-out from the brain was slower for the S-isomer. The striatum to cerebellum ratio for [125I]S-IBZM decreased with an increasing dose of cold carrier or spiperone, suggesting that the brain uptake is stereospecific and saturable, and may be related to the binding of D-2 dopamine receptors. In a dual isotope digital autoradiography study [125I]IBZM and [3H]NMSP(N-methylspiperone) show comparable regional cerebral distribution in rats.

Natural family planning.

It is now well accepted that a woman can conceive from an act of intercourse for a maximum of only about 7 days of her menstrual cycle. The reliability of natural family planning depends on identifying this window of fertility without ambiguity. Several symptomatic markers, cervical mucus and basal body temperature, have been used extensively and with considerable success in most women but failures occur. Ovarian and pituitary hormone production show characteristic patterns during the cycle. Urinary estrogen and pregnanediol measurements yield reliable information concerning the beginning, peak, and end of the fertile period, provided that the assays are accurate and performed on timed specimens of urine. We have developed such enzyme immunoassays for urinary estrogen and pregnanediol glucuronides that can be performed at home. In the early versions of the assays, enzyme reaction rates were measured by eye, but more recently, a simple photoelectronic rate meter has been used. The final problem to be solved is not technologic but whether women are sufficiently motivated to expend the same time and effort each day for 10 days a month, with less cost, on fertility awareness as they spend on making a cup of tea.

[Cervical mucus as a biological sign of fertility and infertility]. / La glaire cervicale: signe biologique de fecondite et d'infecondite.

PIP: The ovulation method makes women aware of certain changes in their cervical mucus. These modifications help to distinguish the beginning and end of the cycle's fertile period and indicate the time of maximum fertility. In addition to pinpointing the date of ovulation, the method permits the user to know she is not fertile when there is no ovulation. The principle of the method is the state of "basic infertility" which preceeds follicular development. The method cannot be implemented with success unless it is properly acquired. After some preliminary considerations regarding the fertile period, ovluation detection and periodic abstinence, some clinical and hormonal observations are compared in 2 basic studies in order to show to what extent cervical mucus reflects ovarian activity. The application of the method requires an understanding of the "basic infertility profile" and 2 sets of rules regarding the 1st days and the peak sign which indicate respectively the beginning and end of the fertile period. The criteria of an ideal birth control method and the importance of proper teaching are also dealt with. With regard to Natural Family Planning, 2 problems are pointed out--incomplete terminology in data collection and absence of a positive and detailed approach to periodic abstinence. (author's modified)^ieng

Natural family planning methods.

PIP: Wade et al.'s report, entitled "A randomized prospective study of the use-effectiveness of 2 methods of natural family planning," contains items worthy of emphasis. These includes the following: 1) less than 5% of the women in the study were prevented from using the method assigned them because of problems in identifying their cervical mucus pattern; 2) those who were unable or unwilling to adhere to the methodology were encouraged to drop out; 3) the largest single category of pregnancies occurred in both groups when the volunteers failed to follow the rules for avoiding pregnancy; 4) it was judged that there were 6 pregnancies in the ovulation method group to be classified as method failures, apparently for a total of 4501 cycles, which gives a method-failure rate of 1.6%; 5) couples were required to sign an informed consent statement of their awareness that the chances of the occurrence of pregnancy could be as high as 25% for the ovulation method; 6) recruiting difficulties constituted an important finding, primarily because they were unexpected by the investigators; 7) the volunteers recruited into the trial were restricted to those women whose menstrual cycles were 24-36 days; 8) the couples who failed to continue with the use of these 2 natural methods--ovulation and temperature rhythm--were on the average younger, more sexually active, and had fewer children; and 9) the ovulation method brings the partners into confrontation with their fertility in each cycle, and this has marked psychological results, including an awakening of the suppressed desire for that fertility to become creative of human life.^ieng

Strokes and contraceptive medication.

PIP: 3 cases of stroke in young women of childbearing age are presented to show the severity of illness and mortality in women using oral contraceptives. All 3 patients smoked more than 15 cigarettes a day. The mortality rate from cerebrovascular disease in OC users has been estimated as 4.7 times that of nonusers. The risk of developing a thrombotic stroke is 9.5 times greater than a control group's. Cerebral infarction has a relatively low mortality rate in young women, 9%, but a nonfatal stroke can have a devastating effect on the patient and her family. While there were no deaths among the 3 cases, each was left with a varying degree of neurological deficit while still in the peak of a normal life span. The possibility of synergistic potentiation of OC-associated cerebral thrombosis by cigarette use is uncertain but studies have noted some correlation between the 2. It is not clear that reduction in estrogen dosage has reduced the risk of cardiac or cerebral disease. The first patient developed extreme symptoms after a heavy drinking session, thereby raising the question of alcohol as a precipitating factor.^ieng