Morphokinetics of human blastocyst expansion in vitro.

Time-lapse imaging offers new tools to study dynamic processes of development such as blastocyst formation and expansion. This study quantitatively describes expansion in human blastocysts from donated oocytes. Measurements of hourly interval rate of changes in the blastocoel cross-sectional area revealed oscillatory pulses having 2-4 h periodicities. Two types of oscillations were distinguished. An E-Type ('expansion') had positive peak and positive or slightly negative trough interval rate of change values, and these characterized most of the expansion period. A C-type ('contraction') represented an infrequent but notable contraction of the blastocoel with loss of blastocoel fluid. These were reversible within 2-4 h in both groups and followed by further expansion. Therefore, oscillatory pulses are an intrinsic property of the trophectoderm. The zona seems to variably dampen the amplitude of these pulses. Expansion kinetics were compared between blastocysts with known positive (KID+) or negative (KID-) implantation outcomes. Regression analysis suggests that expansion may be relatively restricted in KID- embryos blastulating at relatively later times. These data extend observations in other mammalian systems and may provide information useful for clinical selection algorithms.

Study of neuroprotection of donepezil, a therapy for Alzheimer's disease.

Donepezil is a potent acetylcholinesterase inhibitor used for the treatment of Alzheimer's disease. Although acetylcholinesterase inhibitors are thought to be symptomatic treatment of Alzheimer's disease, it is not clear whether they are effective against progressive degeneration of neuronal cells. In this study, we investigated the neuroprotective effects of donepezil against ischemic damage, N-methyl-d-aspartate (NMDA) excitotoxicity, and amyloid-beta (Abeta) toxicity using rat brain primary cultured neurons. Lactate dehydrogenase (LDH) released into the culture medium was measured as a marker of neuronal cell damage. As an ischemic damage model, we used oxygen-glucose deprivation in rat cerebral cortex primary cultured neurons. Pretreatment with donepezil (0.1, 1 and 10 microM) significantly decreased LDH release in a concentration-dependent manner. However, other acetylcholinesterase inhibitors (galantamine, tacrine and rivastigmine) did not significantly decrease LDH release. In a NMDA excitotoxicity model, pretreatment with donepezil (0.1, 1 and 10 microM) decreased the LDH release in a concentration-dependent manner. In binding assay for glutamate receptors, donepezil at 100 microM only slightly inhibited binding to the glycine and polyamine sites on NMDA receptor complex. We further examined the effect of donepezil on Abeta (1-40)- and Abeta (1-42)-induced toxicity in primary cultures of rat septal neurons. Pretreatment with donepezil (0.1, 1 and 10 microM) significantly decreased LDH release induced by Abetas in a concentration-dependent manner. However, other acetylcholinesterase inhibitors (galantamine and tacrine) and NMDA receptor antagonists (memantine and dizocilpine (MK801)) did not significantly decrease LDH release. These results demonstrate that donepezil has protective effects against ischemic damage, glutamate excitotoxicity and Abeta toxicity to rat primary cultured neurons and these effects are not dependent on acetylcholinesterase inhibition and antagonism of NMDA receptors. Thus, donepezil is expected to have a protective effect against progressive degeneration of brain neuronal cells in ischemic cerebrovascular disease and Alzheimer's disease.

Quantitative method of evaluating the functional patency of human uterine tubes. Correlation with 61 laparotomy cases.

PIP: A quantitative method of hydrotubation has been devised using a CO2 insufflator attached to a calibrated burette filled with penicillin-saline solution or plain saline. A constant pressure of 60, 120, or 180 mm of mercury is maintained from a gas cylinder against the saline efflux. The uterine cavity is filled, requiring 3 to 8 ml; then time required for 10 ml of the saline to flow is measured. Delay in flo w indicates tubal obstruction. The method is contraindicated in acute pelvic inflammatory disease, uterine bleeding, ovulation, or elevated body temperature. In more than 3000 tests there were only 2 with complications, in each case severe pain lasting for 1 day. Of the 12 patients who complained of some pain, 11 were later found at laparotomy to have tubal pathology. The preoperative status of tubal patency in 61 infertile patients was compared with findings at laparotomy by using an indigo-carmine dyne in the solution. A correct preoperative diagnosis had been made in 52 patients (85.2%). In 48 in whom tubal patency had b een considered abnormal, 90% were found to be so at laparotomy. In 13 thought to have normal tubes 4 had tubal pathology and in 3 of these there was a normal tube on 1 side. This method is considered more reliable than tubal insufflation (Rubins's test). It is safe, usually painless, and can be done as an office procedure. There is no x-ray exposure as in hysterosalpingography.^ieng

Meconium aspiration syndrome without evidence of fetal distress in early labor before elective cesarean delivery.

Seventy-seven cases of meconium aspiration were documented among 14,527 deliveries. Four cases occurred in early labor and with normal fetal heart tracings. Three cases followed repeat cesarean sections at term, and one followed an elective cesarean section for a primigravid breech presentation. Aggressive airway management was used in every case, and included intrapartum pharyngeal suctioning with a DeLee catheter and intubation of the trachea with suctioning under direct vision. These cases suggest that meconium aspiration may occur before the onset of active labor and without evidence of fetal distress.

Massive fetomaternal hemorrhage preceded by decreased fetal movement and a nonreactive fetal heart rate pattern.

BACKGROUND: Massive fetomaternal hemorrhage occurs in one in 1000 deliveries and has been associated with decreased fetal movements and a sinusoidal fetal heart rate (FHR) pattern. CASES: Three women presented with decreased fetal movements, nonreactive FHR patterns, and positive Kleihauer-Betke tests. All three were at a viable gestational age and were immediately delivered by cesarean. The three infants were severely anemic, with hemoglobin levels of 6.5, 5.3, and 5.1 g/dL, respectively. CONCLUSION: A patient who presents with decreased fetal movement associated with a nonreactive FHR pattern and a positive Kleihauer-Betke test of more than 140 mL should be considered for immediate delivery if the gestational age is consistent with neonatal viability.

What is the significance of the human chorionic gonadotropin value in ectopic pregnancy?

Surgical and pathology data were analyzed with the quantitative serum hCG values from 131 patients with tubal pregnancies. The hCG value correlated with both the size and contents of the eccyesis. Patients with ruptured tubal pregnancies had significantly greater serum hCG levels than did those with intact tubal gestations. Isthmic tubal pregnancies were associated with more frequent rupture and larger amounts of hemoperitoneum than were pregnancies in the ampullary segment of the tube. Tubal rupture with hCG values below 100 mIU/mL occurred in two isthmic pregnancies but in no ampullary pregnancies. With serum hCG levels below 300 mIU/mL, significant hemorrhage did not occur unless the tube was ruptured. Half of the patients had hCG levels sufficient to use a vaginal sonographic hCG discriminatory zone to assist in the diagnosis. A maximum of 15% of tubal pregnancies may be diagnosed by ultrasonographic detection of adnexal cardiac activity. A serum hCG assay sensitive to 10 mIU/mL will detect nearly all tubal pregnancies. The hCG level frequently has diagnostic value when used in conjunction with vaginal sonography. At hCG levels of 100 mIU/mL or less, tubal rupture is very unlikely for ampullary, but not for isthmic, tubal pregnancies.

Direct laparoscopic entry using a sharp and dull trocar technique.

For direct laparoscopic entry using a sharp and dull trocar technique, the sharp trocar is inserted with a twisting motion under constant pressure, then replaced with a dull trocar when a slight loss of resistance is felt. A slow, gradual entry into the peritoneal cavity is accomplished by twisting the dull trocar under constant pressure. Previous major abdominal or pelvic surgery is not a contraindication to this procedure, and use of these trocars, which can be resterilized for every use, may reduce surgical costs by decreasing the need for disposable trocars. This technique has been used in 1655 patients without complication or failure.

A rapid solid-phase radioimmunoassay specific for human chorionic gonadotropin in gestational trophoblastic disease.

A rapid solid-phase radioimmunoassay (RIA) specific for human chorionic gonadotropin (hCG) has been used for the measurement of serum hCG activity in patients with molar pregnancy and gestational trophoblastic disease (GTD). Serum hCG regression as determined by the specific RIA method after evacuation of uncomplicated molar pregnancy was noted to occur over a longer duration of time than previously reported from this Center using a nonspecific RIA system which measures human luteinizing hormone (hLH) and hCG simultaneously. Therapy for proliferative trophoblastic disease was withheld after evacuation of molar pregnancy while the serum hCG level regressed normally, but was instituted when the serum hCG level rose or plateaued for more than two consecutive weeks. Serum hCG levels in patients requiring chemotherapy for GTD were also more accurately monitored with the specific RIA method than with the nonspecific technic. Therapy was based solely on the hCG titer rather than the subsidence of toxicity, as has been our practice in the past. As a result, the duration of hospitalization, total dose of drug required for remission, and toxic side effects were substantially reduced without sacrificing the effectiveness of chemotherapy.

Long-term tocolysis with combined intravenous terbutaline and magnesium sulfate: a 10-year study of 1000 patients.

OBJECTIVE: To determine whether long-term intravenous (IV) tocolysis using combined terbutaline and magnesium sulfate is safe and effective. METHODS: One thousand consecutive women in preterm labor were treated with combination IV tocolytic therapy. Terbutaline was initiated with an infusion rate of 1.75 micrograms/minute and increased to a maximum of 80 micrograms/minute. Magnesium sulfate was infused at 2 g/hour without any bolus and increased to maintain a serum level of 6.5-7.5 mg/dL. Tocolysis was continued until fetal lung maturity was achieved or delivery occurred. RESULTS: Combination tocolytic therapy prolonged pregnancy by a mean (+/- standard deviation) of 61 +/- 23.6 days in 751 women with intact membranes and by 20.5 +/- 17.4 days in 249 with ruptured membranes. The longest durations of continuous IV tocolysis were 123 days in a patient with intact membranes and 77 days in one with ruptured membranes. The most common side effects were nausea and vomiting, followed by chest tightness and shortness of breath. CONCLUSION: Long-term IV tocolysis appeared to be safe and to have acceptable side effects, allowing patients to receive combined terbutaline and magnesium sulfate until delivery.

Persistent ectopic pregnancy.

From 1982-1986, 625 tubal ectopic pregnancies were treated at the University of Hawaii School of Medicine Affiliated Hospitals. The percentage of cases in which the involved tube was preserved increased from 7% in 1982 to 26% in 1986. The presence of persistent trophoblastic tissue was diagnosed by elevated serum levels of the beta subunit of human chorionic gonadotropin (beta-hCG) after conservative surgery in four patients. Three of the four patients developed intra-abdominal hemorrhage and required laparotomy. One patient remained asymptomatic despite elevated beta-hCG levels, which disappeared 60 days after surgery. Evaluation of histologic slides demonstrated persistent intraluminal trophoblastic tissue without invasion in two patients, and extraluminal invasion into the tubal wall in one patient. The use of postoperative serial beta-hCG titers might facilitate recognition of this complication in time to prevent further tubal damage and hemorrhage.

Diagnosis of a supernumerary ovary with human chorionic gonadotropin.

The preoperative diagnosis of ectopic ovarian tissue has been reported only once in the literature. In the present case, differential ovarian and adrenal testing was used to diagnose and aberrant ovarian source of persistently elevated plasma estrogen in a patient who had undergone bilateral oophorectomy and adrenalectomy for metastatic breast carcinoma. The ovarian source was diagnosed by stimulation with human chorionic gonadotropin (hCG), and treatment with human menopausal gonadotropin (hMG) prior to surgery was used to facilitate its location at laparotomy.

Evaluation of the cost-effectiveness of home monitoring of uterine contractions.

In 1988, the major health insurance carrier in the state of Hawaii initiated a prospective study to determine the cost-effectiveness of ambulatory uterine activity monitoring. At the end of the study, 79 patients had completed 3189 days on the monitor. Thirty-six patients (45.6%) did not have preterm labor; the daily monitoring resulted in an average loss to the insurance carrier of $3300 per patient, or $118,800. Forty-three patients (54.4%) experienced preterm labor and were found to have benefited from the monitoring system. Earlier detection of preterm labor and better management of oral tocolysis in this group resulted in earlier initiation of maternal tocolytic therapy, which ultimately decreased the preterm birth rate and hospitalization days in the neonatal intensive care unit. Cost analysis of this group demonstrated an average savings of $24,000 per patient, or an overall savings of $1,032,000. The total group of high-risk patients (79) resulted in a net savings to the insurance carrier of $913,200, or $11,500 per patient, suggesting that use of the ambulatory uterine activity monitoring system significantly reduced the cost associated with preterm labor and early delivery.

Rapid hCG-specific radioimmunoassay for menstrual aspiration.

Fifty-one women with missed periods ranging from 5 to 14 days who suspected a pregnancy underwent an aspiration curettage with a flexible soft-tipped cannula attached to a Karman-type syringe. Sera from these women were measured for human chorionic gonadotropin (hCG) by a rapid 2-hour solid phase radioimmunoassay using an antibody with a specificity for the beta subunit of hCG. The sensitivity and specificity of this assay insured detection of bCG with 100% accuracy at the time of the missed period. Of the 51 women, 33 (64.7%) were found to have hCG in their serum, and 29 (56.8%) had histologic evidence diagnostic of pregnancy.

PIP: Aspiration curettage was performed on 51 women who suspected pregnancy and had missed periods from 5 to 14 days. Sera obtained from the patients were analyzed for human chorionic gonadotropin (HCG) by a rapid, 2-hour solid-phase radioimmunoassay using an antibody with a specificity for the beta subunit of HCG. 33 of the women (64.7%) were found to have serum values ranging from 8 mIU/m1 to 3997 mIU/m1. 29 of the women (56.8%) showed histologic evidence of pregnancy. Generally, more women had HCG in their serum as the number of days following the missed period increased. The test can detect HCG with 100% accuracy at the time of the missed period.

Inhibitory effect of orally administered donepezil hydrochloride (E2020), a novel treatment for Alzheimer's disease, on cholinesterase activity in rats.

Donepezil hydrochloride ((+/-)-2-[(1-benzylpiperidin-4-yl)methyl]-5, 6-dimethoxy-indan-1-one monohydrochloride: E2020: donepezil) is a potent and selective acetylcholinesterase inhibitor developed for the treatment of Alzheimer's disease. The present experiments were designed to compare the inhibitory effects of orally administered donepezil and other cholinesterase inhibitors, tacrine (9-amino-1,2, 3,4-tetrahydroacridine hydrochloride), (S)-N-ethyl-3-[(1-dimethyl-amino)ethyl]-N-methyl-phenylcarbamate hydrogentartrate (ENA-713, rivastigmine) and 3-[1-(phenylmethyl)-4-piperidinyl]-1-(2,3,4, 5-tetrahydro-1H-1-benzazepin-8-yl)-1-propanone fumarate (TAK-147), on the cholinesterase activity in the brain and plasma of rats. Moreover, in order to validate the cholinesterase inhibition data, we measured the brain and plasma concentrations of these drugs. Oral administration of donepezil, tacrine, ENA-713 or TAK-147, caused a dose-dependent inhibition of brain and plasma cholinesterase activities. The ID(50) values of these compounds for brain cholinesterase activity were 6.3, 40.5, 7.2 and 26.8 micromol/kg, respectively. On the other hand, the ID(50)170, 9.7 and 51.2 micromol/kg, respectively. Thus, the ratios of the ID(50)4.2, 1.3 and 1.9, respectively. Brain and plasma concentrations of donepezil, tacrine and TAK-147 increased dose-dependently. The ratios of the concentrations (brain/plasma) of these compounds were 6.1-8.4 for donepezil, 14.5-54.6 for tacrine and 7.0-20.6 for TAK-147. The values of 50% inhibitory concentration of these drugs in the brain were 0.42, 3.5 and 1.1 nmol/g, respectively. In contrast, the brain and plasma concentrations of ENA-713 at all doses, except the two highest doses, were below the quantification limit. These results suggest that orally administered donepezil satisfactorily penetrates into the brain and inhibits cholinesterase there, and that donepezil is a potent and selective inhibitor of brain cholinesterase in comparison with plasma cholinesterase in vivo.

Effect of donepezil hydrochloride (E2020) on basal concentration of extracellular acetylcholine in the hippocampus of rats.

The effects of oral administration of the centrally acting acetylcholinesterase (AChE) inhibitors, donepezil hydrochloride (donepezil: E2020: (+/-)-2-[(1-benzylpiperidin-4-yl)methyl]-5,6-dimethoxy-indan-1-one monohydrochloride), tacrine (9-amino-1,2,3,4-tetrahydroacridine hydrochloride) and ENA-713 (rivastigmine: (S)-N-ethyl-3-[(1-dimethyl-amino)ethyl]-N-methyl-phenylcarbamate hydrogentartrate), which have been developed for the treatment of Alzheimer's disease, on the extracellular acetylcholine concentration in the hippocampus of rats were evaluated by using a microdialysis technique without adding cholinesterase inhibitor to the perfusion solution. We also compared the inhibition of brain AChE and the brain concentrations of these drugs. Donepezil at 2.5 mg/kg and tacrine at 5 mg/kg showed significant effects for more than 6 h. At these doses, the maximum increases were observed at about 1.5 h after administration of donepezil, and at about 2 h with tacrine, and were 499% and 422% of the pre-level, respectively. ENA-713 produced significant effects at doses of 0.625, 1.25 and 2.5 mg/kg, which lasted for about 1, 2 and 4 h, respectively. The maximum increases produced by these doses at about 0.5 h after administration were 190, 346 and 458% of the pre-level, respectively. The time courses of brain AChE inhibition with donepezil at 2.5 mg/kg, tacrine at 10 mg/kg and ENA-713 at 2.5 mg/kg were mirror images of the extracellular acetylcholine-increasing action at the same doses. The time courses of the brain concentrations of drugs after oral administration of donepezil at 2.5 mg/kg and tacrine at 10 mg/kg were consistent with those of brain AChE inhibition at the same doses, and there was a linear relation between these parameters. Brain concentration of ENA-713 at 2.5 mg/kg was below the limit of quantification at all time points measured. These results suggest that oral administration of donepezil, tacrine and ENA-713 increases acetylcholine concentration in the synaptic cleft of the hippocampus mostly through AChE inhibition, and that donepezil has a more potent activity than tacrine and a longer-lasting effect than ENA-713 on the central cholinergic system.

Inhibitory effects of donepezil hydrochloride (E2020) on cholinesterase activity in brain and peripheral tissues of young and aged rats.

Donepezil hydrochloride (donepezil: E2020: (+/-)-2-[(1-benzylpiperidin-4-yl)methyl]-5,6-dimethoxy-indan-1-one monohydrochloride)) is a centrally acting acetylcholinesterase inhibitor developed for the treatment of Alzheimer's disease. In the present study, its inhibitory effect on the activity of cholinesterase ex vivo was evaluated in the brain, plasma, erythrocytes, heart, small intestine, liver and pectoral muscle of young adult as well as aged rats, in comparison with that of tacrine (9-amino-1,2,3,4-tetrahydroacridine hydrochloride). In aged animals, cholinesterase activity in heart, small intestine and pectoral muscle was lower, whereas that in plasma and liver was higher than in young rats. Both groups showed the highest levels in the brain. Donepezil, at doses of 1.25, 2.5 and 5 mg/kg, p.o., inhibited brain, plasma, erythrocyte, liver and pectoral muscle cholinesterase activity in young rats in a dose-dependent manner but had less effect on cholinesterase activity in heart and small intestine. In aged animals, inhibition of cholinesterase activity in the brain, erythrocytes and pectoral muscle by donepezil was more potent than that in young animals. Tacrine, at doses of 5, 10 and 20 mg/kg, p.o., dose-dependently inhibited cholinesterase activity in all tissues of both young and aged animals, but most potently in heart, small intestine and liver. The inhibition of cholinesterase activity by tacrine in the brain, plasma, erythrocytes, heart and liver was more potent in aged rats than in tissues of young rats. Brain and plasma concentrations of unchanged donepezil and tacrine were measured in the same animals as used for the cholinesterase inhibition study. Brain and plasma concentrations of donepezil and tacrine were higher in aged than in young animals. It is concluded that the inhibitory effects of donepezil and tacrine on cholinesterase activity are greater in aged than in young rats, owing to differences in the tissue concentrations of these compounds between young and aged animals. It is also suggested that the effect of donepezil on cholinesterase activity is more tissue-selective than that of tacrine.

Central and peripheral activity of cholinesterase inhibitors as revealed by yawning and fasciculation in rats.

This study was designed to investigate the central and peripheral activity profile of cholinesterase inhibitors in rats. Intravenous injection of cholinesterase inhibitors caused fasciculation, a fine involuntary muscular movement. This peripheral cholinergic sign was tightly correlated with in vitro anti-acetylcholinesterase activity by cholinesterase inhibitors, suggesting that fasciculation is a valid index of peripheral cholinergic activation. Yawning, used as a marker of central cholinergic activation, was also monitored. E2030 (3-(2-(1-(1,3-dioxolan-2-ylmethyl)-4-piperidyl)ethyl)-2H-3,4-dihydro-1,3-benzoxazin-2,4-dione hydrochloride) elicited yawning at more than 4 mg/kg, while fasciculation was significantly intensified only at a dose of 16 mg/kg. Donepezil and tacrine induced both yawning and fasciculation at doses greater than 4 mg/kg, whereas physostigmine induced both behaviors at a dose of 8 mg/kg and above. Finally, ipidacrine elicited yawning at a dose of 16 mg/kg and fasciculation at doses greater than 8 mg/kg. Thus, all putative centrally acting cholinesterase inhibitors elicited yawning. TAK-147 (3-[1-(phenylmethyl)-4-piperidinyl]-1-(2,3,4,5-tetrahydro-1H-benzazepin-8-yl)-1-propanone fumarate) did not significantly elicit yawning at doses under 16 mg/kg, but elicited fasciculation at a dose of more than 4 mg/kg. Distigmine, a peripherally acting cholinesterase inhibitor, evoked fasciculations, but not yawning. When mild to moderate fasciculation was evoked, donepezil and E2030 elicited more than nine yawns over 30 min, while the other cholinesterase inhibitors elicited approximately five yawns at most during this period. These results indicated that E2030 and donepezil exhibited the most marked preferential central cholinergic activity, relative to peripheral activity, among cholinesterase inhibitors tested. Scopolamine, a centrally acting antimuscarinic drug, completely inhibited E2030-induced yawning, while peripherally acting methylscopolamine did not. Haloperidol, a dopamine receptor antagonist, partially blocked E2030-induced yawning, but did not block donepezil-induced yawning. These results suggest that central cholinergic and, in part, dopaminergic mechanisms are involved in E2030-induced yawning.

Microscopic appearance of the human fallopian tube following a reanastomosis procedure.

Microscopic evaluation of a human fallopian tube following end-to-end anastomosis over a polyethylene stent was performed 10 days after the initial surgical procedure. The stent was removed on the 3rd postoperative day. Examination of the excised tube revealed a patent lumen without any evidence of mucosal compromise. The submucosa adjacent to the anastomotic site revealed a mild polymorphonuclear leukocytic infiltration, although a marked inflammatory response was observed around the 5-0 chromic sutures used in the reanastomosis. This case and recent animal studies suggest that early removal of the stent does not appear to jeopardize the patency of the tube and may be preferable to removal after 3 to 4 months.

The significance of beta-adrenoceptor down regulation in the desipramine action in the forced swimming test.

The present studies were undertaken to clarify whether central beta-adrenoceptor down regulation is responsible for the greater effect of chronic treatment with desipramine (DMI) compared with acute treatment in the forced swimming test in rats. Repetitive administration of DMI activated the rat behaviour pattern and consequently reduced the duration of immobility. The degree of activation depended on the length of treatment, i.e. no effect when given in a single dose, moderate effect when given subchronically (3 doses) and marked activation after chronic (31 doses) treatment. Chronic treatment with DMI also produced a decrease in 3H-dihydroalprenolol (3H-DHA) binding site in the cerebral cortex. Acute stimulation of brain beta-adrenoceptors by intracerebroventricular (i.c.v.) isoprenaline significantly, though partially, attenuated the behavioural effect of chronic DMI by beta 1-adrenoceptor-related mechanisms. Similarly, chronic i.c.v. co-administration of atenolol or practolol, beta 1-adrenoceptor antagonists, together with DMI attenuated both beta-adrenoceptor down regulation and the behavioural activation by chronic DMI. On the other hand, chronic i.c.v. administration of isoprenaline, supposedly leading to down regulation of beta-adrenoceptors, facilitated the activating behavioural effect of DMI, as a single dose became effective. Changes, however, in 3H-DHA binding parameters in the cerebral cortex were not observed after chronic isoprenaline. These results suggest that down regulation of beta-adrenoceptors in brain is responsible, at least in part, for the marked activatory effect of chronic DMI in the forced swimming test, possibly by reducing an inhibitory function of beta 1-adrenoceptor mediated mechanisms.

Comparison of inhibitory activities of donepezil and other cholinesterase inhibitors on acetylcholinesterase and butyrylcholinesterase in vitro.

This study was designed to compare the in vitro inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) of donepezil and some other cholinesterase (ChE) inhibitors which have been developed for the treatment of Alzheimer's disease. The carbamate derivatives physostigmine and rivastigmine needed preincubation to exhibit appropriate anti-ChE activity. The maximum ChE inhibition by physostigmine developed within 30-60 min, while the inhibitory effect of rivastigmine on AChE and BuChE activities reached its peak after 48 and 6 h, respectively. The order of inhibitory potency (IC50) towards AChE activity under optimal assay conditions for each ChE inhibitor was: physostigmine (0.67 nM) > rivastigmine (4.3 nM) > donepezil (6.7 nM) > TAK-147 (12 nM) > tacrine (77 nM) > ipidacrine (270 nM). The benzylpiperidine derivatives donepezil and TAK-147 showed high selectivity for AChE over BuChE. The carbamate derivatives showed moderate selectivity, while the 4-aminopyridine derivatives tacrine and ipidacrine showed no selectivity. The inhibitory potency of these ChE inhibitors towards AChE activity may illustrate their potential in vivo activity.