Oviposition by small hive beetles elicits hygienic responses from Cape honeybees

Two novel behaviours, both adaptations of small hive beetles ( Aethina tumida Murray) and Cape honeybees ( Apis mellifera capensis Esch.), are described. Beetles puncture the sides of empty cells and oviposit under the pupae in adjoining cells. However, bees detect this ruse and remove infested brood (hygienic behaviour), even under such well-disguised conditions. Indeed, bees removed 91% of treatment brood (brood cells with punctured walls caused by beetles) but only 2% of control brood (brood not exposed to beetles). Only 91% of treatment brood actually contained beetle eggs; the data therefore suggest that bees remove only that brood containing beetle eggs and leave uninfected brood alone, even if beetles have accessed (but not oviposited on) the brood. Although this unique oviposition strategy by beetles appears both elusive and adaptive, Cape honeybees are able to detect and remove virtually all of the infested brood.

Prison construction and guarding behaviour by European honeybees is dependent on inmate small hive beetle density

Increasing small hive beetle (Aethina tumida Murray) density changes prison construction and guarding behaviour in European honeybees (Apis mellifera L.). These changes include more guard bees per imprisoned beetle and the construction of more beetle prisons at the higher beetle density. Despite this, the number of beetles per prison (inmate density) did not change. Beetles solicited food more actively at the higher density and at night. In response, guard bees increased their aggressive behaviour towards beetle prisoners but did not feed beetles more at the higher density. Only 5% of all beetles were found among the combs at the low density but this percentage increased five-fold at the higher one. Successful comb infiltration (and thus reproduction) by beetles is a possible explanation for the significant damage beetles cause to European honeybee colonies in the USA.

Benzodiazepines as potent and selective bradykinin B1 antagonists

Antagonism of the bradykinin B(1) receptor was demonstrated to be a potential treatment for chronic pain and inflammation. Novel benzodiazepines were designed that display subnanomolar affinity for the bradykinin B(1) receptor (K(i) = 0.59 nM) and high selectivity against the bradykinin B(2) receptor (K(i) > 10 microM). In vivo efficacy, comparable to morphine, was demonstrated for lead compounds in a rodent hyperalgesia model.

Does direct ophthalmoscopy improve retinal screening for diabetic eye disease by retinal photography?

AIMS

To identify whether after performing retinal photography, direct ophthalmoscopy can improve the yield of screening for the detection of sight-threatening diabetic eye disease (STDED).

METHODS

Patients (n = 408) who had previously received both dilated direct ophthalmoscopy by a diabetologist and retinal photography graded by a diabetologist within 3 months of each other were included. The results of the other screening modality were not available to the grader/screener. The first 308 patients were consecutive attendees at the clinic who fulfilled the study criteria and 100 were selected because they were identified as having potential STDED by either one of these modalities. An ophthalmologist using slit lamp biomicroscopy then examined patients identified with potential STDED.

RESULTS

In 357 (88%) patients there was agreement between the two modalities about whether referral to an ophthalmologist was required (kappa 0.62). Retinal photography identified 38 patients for referral to ophthalmology which ophthalmoscopy missed. Of these, the ophthalmologist agreed that STDED was present in 32 (84%) and four patients required early laser. Ophthalmoscopy identified 13 patients for referral who were not identified by photography. Of these, the ophthalmologist agreed with the diabetologist that STDED was present in seven (54%) and one patient required early laser.

CONCLUSION

Ophthalmoscopy may identify the occasional patient with diabetes who has STDED which is missed by retinal photography. For a systematic retinal screening programme, adding ophthalmoscopy to retinal photography will increase false-positive referrals and is likely to detect only a few extra patients requiring laser.

Small hive beetles survive in honeybee prisons by behavioural mimicry

We report the results of a simple experiment to determine whether honeybees feed their small hive beetle nest parasites. Honeybees incarcerate the beetles in cells constructed of plant resins and continually guard them. The longevity of incarcerated beetles greatly exceeds their metabolic reserves. We show that survival of small hive beetles derives from behavioural mimicry by which the beetles induce the bees to feed them trophallactically. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at htpp://dx.doi.org/10.1007/s00114-002-0326-y.

PSA-specific and non-PSA-specific conversion of a PSA-targeted peptide conjugate of doxorubicin to its active metabolites

Tumor-selective delivery of doxorubicin by a prostate-specific antigen (PSA)-targeted peptide conjugate prodrug of doxorubicin was demonstrated in a nude mouse xenograft model of human prostate cancer. The prodrug (referred to as doxorubicin conjugate) contains doxorubicin linked to a seven-amino acid peptide conjugate that was designed to increase delivery of doxorubicin to tumor sites through the hydrolytic properties of PSA, which prostate tumors express in high amounts. Following i.p. administration of the doxorubicin conjugate to mice, tumor exposure to doxorubicin was increased 2.5-fold as compared with that achieved after an equimolar dose of doxorubicin itself. However, in heart tissue, the site of clinical dose-limiting toxicity, doxorubicin concentrations observed after administration of doxorubicin conjugate were substantially lower than those in mice that received doxorubicin itself. While the prodrug provided selective delivery of doxorubicin to tumor tissue, there was substantial non-PSA-specific formation of doxorubicin in laboratory animals, a factor that would limit the extent of therapeutic gain of the prodrug. Following i.v. administration to mice, rats, dogs, and monkeys, about one-third of the dose was metabolized to doxorubicin. In tumor-bearing mice, the fraction of the dose metabolized to doxorubicin appeared even higher. This is likely the result of conjugate conversion to doxorubicin by both PSA-specific (in tumor) and non-PSA-specific proteolytic activities. In vitro studies provided further support for the PSA specificity of metabolism; LNCaP cells mediated rapid metabolism of the conjugate, while DuPRO-1 cells, which are deficient in PSA, were incapable of metabolism.

Glaucoma incidence in an unselected cohort of diabetic patients: is diabetes mellitus a risk factor for glaucoma? DARTS/MEMO collaboration. Diabetes Audit and Research in Tayside Study. Medicines Monitoring Unit

AIMS

To evaluate whether diabetes mellitus is a risk factor for the development of primary open angle glaucoma or ocular hypertension (OHT).

METHODS

A historical cohort study of an unselected population comprising all residents of the Tayside region of Scotland was performed using record linkage techniques followed by case note review. Ascertainment of prevalent diabetes was achieved using the Diabetes Audit and Research in Tayside Study (DARTS) validated regional diabetes register. Glaucoma and treated OHT were defined by encashment of community prescriptions and the statutory surgical procedure coding database.

RESULTS

The study population comprised 6631 diabetic subjects and 166 144 non-diabetic subjects aged >40 years without glaucoma or OHT at study entry. 65 patients with diabetes and 958 without diabetes were identified as new cases of glaucoma or treated OHT during the 24 month study period, yielding a standardised morbidity ratio of 127 (95% CI, 96-158). Case note review demonstrated non-differential misclassification of prevalent glaucoma and OHT as incident disease (diabetic cohort 20%, non-diabetic cohort 24%; p=0.56) primarily as a result of non-compliance in medically treated disease. Removing misclassified cases and adjusting for age yielded an incidence of primary open angle glaucoma in diabetes of 1.1/1000 patient years (95% CI, 0.89-1. 31) compared to 0.7/1000 patient years (95% CI, 0.54-0.86) in the non-diabetic cohort; RR 1.57 (95% CI, 0.99-2.48).

CONCLUSIONS

This study failed to confirm an association between diabetes mellitus and primary open angle glaucoma and ocular hypertension. A non-significant increase in diagnosed and treated disease in the diabetic population was observed, but evidence was also found that detection bias contributes to this association.

In vitro and in vivo evaluation of dihydropyrimidinone C-5 amides as potent and selective alpha(1A) receptor antagonists for the treatment of benign prostatic hyperplasia

alpha(1) Adrenergic receptors mediate both vascular and lower urinary tract tone, and alpha(1) receptor antagonists such as terazosin (1b) are used to treat both hypertension and benign prostatic hyperplasia (BPH). Recently, three different subtypes of this receptor have been identified, with the alpha(1A) receptor being most prevalent in lower urinary tract tissue. This paper explores 4-aryldihydropyrimidinones attached to an aminopropyl-4-arylpiperidine via a C-5 amide as selective alpha(1A) receptor subtype antagonists. In receptor binding assays, these types of compounds generally display K(i) values for the alpha(1a) receptor subtype <1 nM while being greater than 100-fold selective versus the alpha(1b) and alpha(1d) receptor subtypes. Many of these compounds were also evaluated in vivo and found to be more potent than terazosin in both a rat model of prostate tone and a dog model of intra-urethral pressure without significantly affecting blood pressure. While many of the compounds tested displayed poor pharmacokinetics, compound 48 was found to have adequate bioavailability (>20%) and half-life (>6 h) in both rats and dogs. Due to its selectivity for the alpha(1a) over the alpha(1b) and alpha(1d) receptors as well as its favorable pharmacokinetic profile, 48 has the potential to relieve the symptoms of BPH without eliciting effects on the cardiovascular system.

Surgery for full-thickness macular holes with short-duration prone posturing: results of a pilot study

PURPOSE

To see whether surgical success and complication rates in surgery for full-thickness macular holes (FTMH) followed by 5 days prone posturing are comparable to those obtained with longer posturing regimes recorded in the literature.

METHODS

A pilot study was carried out of pars plana vitrectomy, autologous platelet adjunct and 16% C2F6 tamponade followed by 5 days prone posturing in 38 eyes of 34 patients with idiopathic FTMH. A follow-up postal questionnaire was used to assess patients' perception of posturing and outcome.

RESULTS

Fifty-three per cent of eyes gained 2 or more lines of Snellen acuity. Twenty-four per cent of patients with symptom duration of 12 months or less (29 patients) achieved a visual acuity of 6/12. Fifty-eight per cent of patients achieved N8 or better near vision. The only significant predictor of post-operative Snellen acuity was the stage of the hole (p = 0.02). Eighty-six per cent of questionnaire respondents felt that surgery had improved their quality of life. Eighty-seven per cent of all patients reported a reduction in, or elimination of, metamorphopsia. Fifty-four per cent of patients described posturing for 5 days as difficult or very difficult. Five patients admitted to posturing for less than 12 h a day, but all stated that they had postured for the full 5 days. Cataract was the commonest complication observed in this series (42% of patients have had or been listed for cataract surgery).

CONCLUSIONS

Five days of prone posturing following vitrectomy for FTMH with autologous plaletet concentrate and C2F6 tamponade afforded success and complication rates comparable to those in published studies with longer posturing times.

Adrenal mass evaluation in patients with lung carcinoma: a cost-effectiveness analysis

OBJECTIVE

This study evaluates the cost-effectiveness of various imaging and biopsy strategies for characterizing adrenal masses in patients with newly diagnosed non-small cell carcinoma of the lung.

MATERIALS AND METHODS

A decision-analysis model was used to compare the cost-effectiveness of nine strategies. Initial imaging included unenhanced CT using an adenoma or nonadenoma threshold of 0 or 10 H or in- and opposed-phase MR imaging. When initial imaging did not confirm an adenoma, CT-guided biopsy or subsequent imaging was performed. Medicare reimbursement was used as a surrogate of cost. Net costs were calculated as the difference in costs between two limbs of the decision tree. Net benefits were calculated as the difference between strategies and were calculated for life expectancy in years. MR imaging, CT, and biopsy accuracy, average life expectancy, and surgical mortality rates were based on the literature.

RESULTS

The base case analysis determined that the most cost-effective strategy was CT with an adenoma or nonadenoma threshold of 10 H followed by MR imaging, if necessary. CT with a threshold of 0 H followed by biopsy, if necessary, was the least costly. The incremental cost-effectiveness ratio between these two strategies was $16,370 per year of life gained.

CONCLUSION

Unenhanced CT using a 10 H threshold followed by MR imaging, if needed, was the most cost-effective strategy for evaluating an adrenal mass in a patient with newly diagnosed non-small cell lung cancer.

Disposition and pharmacokinetics of the antimigraine drug, rizatriptan, in humans

The absorption and disposition of rizatriptan (MK-0462, Maxalt(TM)), a selective 5-HT(1B/1D) receptor agonist used in the treatment of migraine headaches, was investigated in humans. In a two-period, single i.v. (3 mg, 30-min infusion), and single oral (10 mg) dose study with [(14)C]rizatriptan in six healthy human males, total recovery of radioactivity was approximately 94%, with unchanged rizatriptan and its metabolites being excreted mainly in the urine (89% i.v. dose, 82% p.o. dose). Approximately 26 and 14% of i.v. and oral rizatriptan doses, respectively, were excreted in urine as intact parent drug. In a second, high-dose study (60 mg p.o.), five metabolites excreted into urine were identified using liquid chromatography-tandem mass spectrometry and NMR methods. They were triazolomethyl-indole-3-acetic acid, rizatriptan-N(10)-oxide, 6-hydroxy-rizatriptan, 6-hydroxy-rizatriptan sulfate, and N(10)-monodesmethyl-rizatriptan. Urinary excretion of triazolomethyl-indole-3-acetic acid after i.v. and oral administrations of rizatriptan accounted for 35 and 51% of the dose, respectively, whereas the corresponding values for rizatriptan-N(10)-oxide were 4 and 2% of the dose. Plasma clearance (CL) and renal clearance (CL(r)) were 1325 and 349 ml/min, respectively, after i.v. administration. A similar CL(r) value was obtained after oral administration (396 ml/min). The primary route of rizatriptan elimination occurred via nonrenal route(s) (i.e., metabolism) because the CL(r) of rizatriptan accounted for 25% of total CL. Furthermore, the CL(r) was higher than normal glomerular filtration rate ( approximately 130 ml/min), indicating that this compound was actively secreted by renal tubules. The absorption of rizatriptan was approximately 90%, but it experienced a moderate first-pass effect, resulting in a bioavailability estimate of 47%.

In vitro and in vivo studies on the metabolism of tirofiban

Tirofiban hydrochloride [L-tyrosine-N-(butylsulfonyl)-O-[4-(4-piperidinebutyl)] monohydrochloride, is a potent and specific fibrinogen receptor antagonist. Radiolabeled tirofiban was synthesized with either (3)H-label incorporated into the phenyl ring of the tyrosinyl residue or (14)C-label in the butane sulfonyl moiety. Neither human liver microsomes nor liver slices metabolized [(14)C]tirofiban. However, male rat liver microsomes converted a limited amount of the substrate to a more polar metabolite (I) and a relatively less polar metabolite (II). The formation of I was sex dependent and resulted from an O-dealkylation reaction catalyzed by CYP3A2. Metabolite II was identified as a 2-piperidone analog of tirofiban. There was no evidence for Phase II biotransformation of tirofiban by microsomes fortified with uridine-5'-diphospho-alpha-D-glucuronic acid. After a 1 mg/kg i.v. dose of [(14)C]tirofiban, recoveries of radioactivity in rat urine and bile were 23 and 73%, respectively. Metabolite I and unchanged tirofiban represented 70 and 30% of the urinary radioactivity, respectively. Tirofiban represented >90% of the biliary radioactivity. At least three minor biliary metabolites represented the remainder of the radioactivity. One of them was identified as I. Another was identified as II. When dogs received 1 mg/kg i.v. of [(3)H]tirofiban, most of the radioactivity was recovered in the feces as unchanged tirofiban. The plasma half-life of tirofiban was short in both rats and dogs, and tirofiban was not concentrated in tissues other than those of the vasculature and excretory organs.

Can congenital nasolacrimal-duct obstruction interfere with visual development? A cohort case control study

PURPOSE

To ascertain if tear film disturbance in congenital nasolacrimal-duct obstruction (CNLDO) interferes with visual maturation.

METHODS

Review of a cohort of children in which the occurrence and duration of CNLDO had been previously documented. Information obtained included acuity, refractive data, and presence or absence of strabismus. The incidence of abnormality in the CNLDO group was compared with that in controls, which were fellow eyes in those children with unilateral obstruction, and all children with no history of CNLDO.

RESULTS

Of 4792 children, visual acuity data were obtained on 2249. There was no difference in the incidence of amblyopia in CNLDO children compared with controls (p < 0.89) nor in the watering eye compared with the fellow eye (p < 0.58). No correlation between refractive error or astigmatism and CNLDO (p < 0.26 and p < 0.32 respectively) was found. Strabismus was no more common in CNLDO than in controls (p < 0.89).

CONCLUSIONS

This study found no evidence to suggest that visual maturation is adversely affected by allowing spontaneous resolution of CNLDO.

Effects of pentobarbital on pharmacokinetics and pharmacodynamics of a potent fibrinogen receptor antagonist, L-734,217, in dogs

Effects of pentobarbital on pharmacokinetics and pharmacodynamics of L-734,217, a potent fibrinogen receptor antagonist, were studied in male dogs. L-734,217 was given intravenously at 0.01 mg kg-1, in a cross-over fashion, to conscious dogs or to dogs anesthetized with pentobarbital. Plasma concentrations of L-734,217 were measured using a radioimmunoassay and inhibitory effects on ex vivo platelet aggregation induced by ADP or collagen were determined. In pentobarbital-treated dogs, L-734,217 plasma concentrations during the first 3 h collection period were significantly higher than those in the control animals. Corresponding to the increased plasma levels, the mean ex vivo inhibitory effects on ADP- or collagen-induced platelet aggregation in dogs under anesthesia appeared greater than in those without the anesthetic treatment. Pharmacokinetic analysis revealed a modest, but significant (up to 40%) elevation in the area under the plasma concentration-time curve during 6 h of the drug administration, and a reduction in L-734,217 plasma clearance and volumes of distribution, in the anesthetized dogs. Analysis of pharmacodynamic data indicated that the EC50 and the Hill coefficient of the platelet aggregation response-plasma concentration curve were not altered by pentobarbital treatment. The results are in agreement with the findings that the administration of pentobarbital alone (in the absence of L-734,217) did not affect appreciably the ex vivo platelet aggregatory responses. In a separate group of dogs, L-734,217 was found to be metabolically stable, and was eliminated unchanged renally (64 +/- 4%) and hepatically (32 +/- 6%). In addition, L-734,217 did not bind substantially to canine plasma proteins or blood cellular components. It is possible that alterations of regional hemodynamics, reportedly mediated by pentobarbital, contributed to changes observed in the present study. That is, alterations occurred in L-734,217 elimination and distribution processes which resulted in an increase in drug plasma levels. Since pentobarbital anesthesia influenced only the pharmacokinetics, and not the pharmacodynamics, of L-734,217, the apparent increases in the inhibition of platelet aggregation responses observed following L-734,217 administration to the anesthetized dogs were probably sequential effects of the pharmacokinetic interactions.

Infertility treatment and multiple birth rates in Britain, 1938-94

Trends in multiple birth rates are thought to have been substantially affected by subfertility treatments in the last 25 years, but there are few quantitative assessments of this. This paper examines trends in twin and higher multiple birth rates separately in Scotland, England and Wales and compares their course with corresponding multiple birth rates in the Oxford Record Linkage Study area, where the proportions following subfertility treatment are documented. National data on prescriptions for subfertility treatments reinforce the view that they have had a major effect on the trends, and currently perhaps 60% of triplet and higher order births and 15% of twins follow their use in Britain.

Use of LC-MS/MS to cross-validate a radioimmunoassay for the fibrinogen receptor antagonist, Aggrastat (tirofiban hydrochloride) in human plasma

A method based on LC-MS/MS was developed for the determination of the fibrinogen-receptor antagonist Aggrastat in human plasma. The drug is isolated from plasma by liquid extraction and converted into its N-trifluoroacetyl derivative prior to analysis by HPLC with atmospheric pressure negative chemical ionization MS/MS detection. A structural analog is used as the internal standard and the lower quantifiable limit of the assay is 0.4 ng ml-1 with a relative standard deviation of 7%. This assay was used to cross-validate the existing immunoassay by analysis of plasma from patients receiving the drug. The specificity of the immunoassay was thereby confirmed.

Species and organ differences in first-pass metabolism of the ester prodrug L-751,164 in dogs and monkeys. In vivo and in vitro studies

The pharmacokinetics and bioavailability of L-751,164, an ethyl ester prodrug of a potent fibrinogen receptor antagonist, L-742,998, were studied in beagle dogs and rhesus monkeys. In both species, L-751,164 exhibited high clearance. After an intravenous dose, L-751,164 was converted to the parent L-742,998 to the extent of approximately 20% in dogs and 90% in monkeys. After oral administration of the prodrug, however, the bioavailability, measured either as the prodrug or as the active parent, was < 5% in both species. Several experiments were conducted subsequently to investigate possible causes for the observed similarities in the low oral bioavailability of the prodrug between species despite its differences in the in vivo conversion. In vitro metabolism studies using dog liver subcellular fractions indicated extensive metabolism of L-751,164 to metabolites other than L-742,998. Kinetically, L-742,998 formation accounted only for approximately 25% of the prodrug disappearance. In contrast, monkey liver preparations converted L-751,164 exclusively and rapidly to L-742,998. Good agreement between the in vitro hepatic metabolism and the in vivo observations suggests that liver was the major eliminating organ after intravenous administration of the prodrug in both species. In dogs, this suggestion was further supported by low bioavailability of the prodrug (20%) and the parent (below detection limit) after intraportal administration of the prodrug. In vitro metabolism of L-751,164 using intestinal S9 fractions revealed substantial metabolism in monkeys, but not in dogs. Several NADPH-dependent metabolites were observed with monkey intestinal preparation, with the parent L-742,998 being the minor product (approximately 25-30%). Furthermore, L-751,164 was shown, by means of an in vitro Caco-2 cell, and in situ rat intestinal loop models, to be highly permeable to intestinal barriers. Collectively, these results suggest that the apparent species differences in the prodrug conversion observed in vivo likely were due to species differences in the hepatic metabolism of the prodrug. In both species, the high first-pass metabolism of the prodrug, and the extensive conversion of the prodrug to metabolic products other than the parent contributed, at least in part, to the low bioavailability of the prodrug and active parent, respectively, obtained after an oral dose of the prodrug. The latter process was species-dependent, involving primarily the hepatic first-pass elimination in dogs and the intestinal first-pass metabolism in monkeys.

Quantitation of the 5HT1D agonists MK-462 and sumatriptan in plasma by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

The 5HT1D agonist sumatriptan is efficacious in the treatment of migraines. MK-462 is a drug of the same class which is under development in our laboratories. Bioanalytical methods of high efficiency, specificity and sensitivity were required to support the preclinical and clinical programs. These assays were based on HPLC with tandem MS-MS detection. MK-462 and sumatriptan were extracted using an automated solid-phase extraction technique on a C2 Varian Bond-Elut cartridge. The n-diethyl analogues of MK-462 and sumatriptan were used as internal standards. The analytes were chromatographed using reversed-phase (nitrile) columns coupled via a heated nebulizer interface to an atmospheric pressure chemical ionization source. The chromatographic run times were less than 7 min. Both methods were precise, accurate and selective down to plasma concentrations of 0.5 ng/ml. The assay for MK-462 was adapted to separately monitor the unlabeled and 14C-labeled species of the drug following intravenous administration of radiolabeled material to man.

The development and cross-validation of methods based on radioimmunoassay and LC/MS-MS for the quantification of the class III antiarrhythmic agent, MK-0499, in human plasma and urine

An analytical method based on radioimmunoassay (RIA) has been developed for the determination of the antiarrhythmic agent, MK-0499, in plasma and urine. Owing to the potency of the drug, the specificity of this assay in human plasma could not be adequately determined using conventional RIA procedures. A highly specific procedure, based on LC/MS-MS, was developed to cross-validate the RIA. The lower quantifiable limits of the RIA and LC/MS-MS-based methods were 0.05 and 0.013 ng ml-1, respectively. Cross-validation data, compared using paired student's t-test regression analysis, showed excellent correlation between methods. The mass spectrometric assay was also used to simultaneously measure plasma concentrations of unlabeled and 14C-labeled MK-0499 following administration of the drug at high specific activity to volunteers.

Species differences in the metabolism of a potent HIV-1 reverse transcriptase inhibitor L-738,372. In vivo and in vitro studies in rats, dogs, monkeys, and human

In vivo and in vitro metabolism of 6-chloro-4(S)-cyclopropyl-3,4-dihydro-4-((2-pyridyl) ethynyl)quinazolin-2(1H)-one (L-738,372), a potent human immunodeficiency virus-type 1 reverse transcriptase inhibitor, has been investigated in rats, dogs, and monkeys. Following 0.9 mg/kg iv and 9 mg/kg po doses, systemic blood clearance (CLB) and bioavailability (F) of L-738,372 were species-dependent and inversely related (CLB = 48, 15, and 3 ml/min/kg; F = 6, 62 and 94%, in dogs, rats, and monkeys, respectively). Incubation of L-738,372 with rat liver slices and liver microsomes from all species studied led to the formation of two hydroxylated metabolites, M1 and M2. Kinetic studies of the microsomal metabolism of L-738,372 indicated that M1 was formed by a much higher affinity, but lower capacity enzyme(s) than that which catalyzed M2 formation in rats, dogs, and monkeys. The total intrinsic clearance of metabolite formation (CL(int) total = CL(int) M1 + CL(int) M2) was highest in dogs, followed by rats and monkeys. In dogs, CL(int) total was caused almost exclusively by CL(int) M1. Extrapolation of the CL(int) total values to the hepatic clearances (19, 8.4, and 0.9ml/min/kg in dogs, rats, and monkeys, respectively) showed a similar rank order to the CLB observed in vivo. Good agreement between these in vivo and in vitro results suggests that the species differences in hepatic first-pass metabolism, and not the intrinsic absorption, contributed significantly to the observed differences in F.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics and pharmacodynamics of L-703,014, a potent fibrinogen receptor antagonist, after intravenous and oral administration in the dog

The pharmacokinetics and pharmacodynamics of L-703,014, a fibrinogen receptor antagonist, have been examined in the dog. An analytical method which utilizes methanol precipitation of dog plasma proteins followed by HPLC with an automated column switching technique using the chemical analogue L-704,326 as internal standard was developed for the determination of L-703,014 in dog plasma. The compound was not metabolized in the dog and was eliminated in the kidneys and into bile. Of the administered dose, 68.9 +/- 1.3% (i.v.) and 80.5 +/- 11.9% (p.o.) were recovered in the feces; 20.3 +/- 1.3% (i.v.) and 2.2 +/- 0.2% (p.o.) were recovered in the urine by 72 hr. L-703,014 was 23 +/- 3.4% bound in dog plasma protein and the mean ratio of plasma/whole blood was 1.22 +/- 0.05. The mean terminal half-life was 118 +/- 36 min, the mean steady-state volume of distribution was 0.61 +/- 0.22 L/kg, and the mean plasma clearance was 8 +/- 2 mL/min/kg. Ex vivo platelet aggregation measurements were made by inducing platelet aggregation with 10 micrograms/mL collagen in the presence of 1 microM epinephrine as an agonist. The mean C50 was 44.4 +/- 6.0 ng/mL, and the mean Hill coefficient was 1.5 +/- 0.3. The mean bioavailability was 4.9 +/- 1.4% in dogs administered 2.0 mg/kg (p.o.).

A controlled assessment of direct intraperitoneal insemination

OBJECTIVE

To test the efficacy of direct intraperitoneal (IP) insemination and its effect on cell-mediated immunity.

DESIGN

A prospective trial with each couple having one treatment (insemination) cycle and one control (timed intercourse) cycle performed in random order with the same ovulation stimulation in both cycles.

SETTING

Secondary and tertiary referral fertility clinics; university teaching hospital.

PATIENTS

Twenty-six infertile couples. Excluding pregnancy, only one couple did not complete the two cycles.

INTERVENTIONS

Ovulation induction in both cycles. Intraperitoneal insemination in the insemination cycles.

MAIN OUTCOME MEASURES

These were pregnancy rate (treatment versus control) and mixed lymphocyte response (MLR) sensitivity (before and after direct IP insemination treatment).

RESULTS

There were four control and no treatment pregnancies. This was not a significant difference (odds ratio). Mixed lymphocyte responses in fertile subjects did not change during the menstrual cycle (Wilcoxon). There was no significant increase in MLR sensitivity to partner's cells after direct IP insemination treatment.

CONCLUSIONS

This controlled study found no benefit from direct IP insemination in terms of pregnancies over control cycles. There was no evidence that direct IP insemination had increased cell-mediated immune response sensitivity to husband's cells.