Managed and Wild Bee Flower Visitors and Their Potential Contribution to Pollination Services of Low-Chill Highbush Blueberry (Vaccinium corymbosum L.; Ericales: Ericaceae)

Highbush blueberry (Vaccinium corymbosum L.; Ericales: Ericaceae) is an important crop grown throughout the eastern United States and Canada. Cross-pollination by insects greatly enhances pollination and fruit set in highbush blueberry. In Florida, low-chill cultivars that flower during the winter when most bees are dormant are used, thus, making it difficult to utilize and depend on unmanaged bees. We investigated flower visitation rates by managed and wild bees and the subsequent berry formation, berry weight, and number of seeds/berry in highbush blueberry fields in north-central Florida. Additionally, we tested three pollinator treatments: 1) pollinator-excluded flowers, 2) open-pollinated treatments that were available to managed and wild bees, and 3) flowers that were hand pollinated. Overall, we found seven native bee species that contribute to highbush blueberry pollination in Florida, but managed honey bees and bumble bees were the main flower visitors. Additionally, 14.5 times more blueberries formed in the open treatments than in the pollinator exclusion treatments, thus illustrating the economic impact bees have on blueberry pollination. Most of the wild bees observed visiting blueberry flowers were ground-nesting species that need uncultivated areas for nesting sites. Therefore, leaving field edges uncultivated and some undisturbed habitat may increase native bee numbers within blueberry farms over time.

Managed Bumble Bees (Bombus impatiens) (Hymenoptera: Apidae) Caged With Blueberry Bushes at High Density Did Not Increase Fruit Set or Fruit Weight Compared to Open Pollination

Highbush blueberry (Vaccinium corymbosum L.) is an important crop grown throughout Florida. Currently, most blueberry growers use honey bees (Apis mellifera L.) to provide pollination services for highbush blueberries even though bumble bees (Bombus spp.) have been shown to be more efficient at pollinating blueberries on a per bee basis. In general, contribution of bumble bees to the pollination of commercial highbush blueberries in Florida is unknown. Herein, we determined if managed bumble bees could contribute to highbush blueberry pollination. There were four treatments in this study: two treatments of caged commercial bumble bee (Bombus impatiens Cresson) colonies (low and high weight hives), a treatment excluding all pollinators, and a final treatment which allowed all pollinators (managed and wild pollinators) in the area have access to the plot. All treatments were located within a highbush blueberry field containing two cultivars of blooming plants, 'Emerald' and 'Millennia', with each cage containing 16 mature blueberry plants. We gathered data on fruit set, berry weight, and number of seeds produced per berry. When pollinators were excluded, fruit set was significantly lower in both cultivars (<8%) compared to that in all of the other treatments (>58%). Berry weight was not significantly different among the treatments, and the number of seeds per berry did not show a clear response. This study emphasizes the importance of bumble bees as an effective pollinator of blueberries and the potential beneficial implications of the addition of bumble bees in commercial blueberry greenhouses or high tunnels.

Precision large field scanning system for high numerical aperture lenses and application to femtosecond micromachining of ophthalmic materials

A precision, large stroke (nearly 1 cm) scanning system was designed, built, and calibrated for micromachining of ophthalmic materials including hydrogels and cornea (excised and in vivo). This system comprises a flexure stage with an attached objective on stacked vertical and horizontal translation stages. This paper outlines the design process leading to our most current version including the specifications that were used in the design and the drawbacks of other methods that were previously used. Initial measurements of the current version are also given. The current flexure was measured to have a 27 Hz natural frequency with no load.

Protein levels and colony development of Africanized and European honey bees fed natural and artificial diets

Pollen substitute diets are a valuable resource for maintaining strong and health honey bee colonies. Specific diets may be useful in one region or country and inadequate or economically unviable in others. We compared two artificial protein diets that had been formulated from locally-available ingredients in Brazil with bee bread and a non-protein sucrose diet. Groups of 100 newly-emerged, adult workers of Africanized honey bees in Brazil and European honey bees in the USA were confined in small cages and fed on one of four diets for seven days. The artificial diets included a high protein diet made of soy milk powder and albumin, and a lower protein level diet consisting of soy milk powder, brewer's yeast and rice bran. The initial protein levels in newly emerged bees were approximately 18-21 µg/µL hemolymph. After feeding on the diets for seven days, the protein levels in the hemolymph were similar among the protein diet groups (~37-49 µg/µL after seven days), although Africanized bees acquired higher protein levels, increasing 145 and 100% on diets D1 and D2, respectively, versus 83 and 60% in the European bees. All the protein diets resulted in significantly higher levels of protein than sucrose solution alone. In the field, the two pollen substitute diets were tested during periods of low pollen availability in the field in two regions of Brazil. Food consumption, population development, colony weight, and honey production were evaluated to determine the impact of the diets on colony strength parameters. The colonies fed artificial diets had a significant improvement in all parameters, while control colonies dwindled during the dearth period. We conclude that these two artificial protein diets have good potential as pollen substitutes during dearth periods and that Africanized bees more efficiently utilize artificial protein diets than do European honey bees.

Susceptibility of Aethina tumida (Coleoptera: Nitidulidae) larvae and pupae to entomopathogenic nematodes

In this study, we evaluated the potential use of entomopathogenic nematodes as a control for the beetle Aethina tumida Murray (Coleoptera: Nitidulidae). In particular, we conducted 1) four screening bioassays to determine nematode (seven species, 10 total strains tested) and application level effects on A. tumida larvae and pupae, 2) a generational persistence bioassay to determine whether single inoculations with nematodes would control multiple generations of A. tumida larvae in treated soil, and 3) a field bioassay to determine whether the nematodes would remain efficacious in the field. In the screening bioassays, nematode efficacy varied significantly by tested nematode and the infective juvenile (IJ) level at which they were applied. Although nematode virulence was moderate in screening bioassays 1-3 (0-68% A. tumida mortality), A. tumida mortality approached higher levels in screening bioassay 4 (nearly 100% after 39 d) that suggest suitable applicability of some of the test nematodes as field controls for A. tumida. In the generational persistence bioassay, Steinernema riobrave Cabanillas, Poinar & Raulston 7-12 strain and Heterorhabditis indica Poinar, Karunaka & David provided adequate A. tumida control for 19 wk after a single soil inoculation (76-94% mortality in A. tumida pupae). In the field bioassay, the same two nematode species also showed high virulence toward pupating A. tumida (88-100%) mortality. Our data suggest that nematode use may be an integral component of an integrated pest management scheme aimed at reducing A. tumida populations in bee colonies to tolerable levels.

The efficacy of small cell foundation as a varroa mite (Varroa destructor) control

Due to a continuing shift toward reducing/minimizing the use of chemicals in honey bee colonies, we explored the possibility of using small cell foundation as a varroa control. Based on the number of anecdotal reports supporting small cell as an efficacious varroa control tool, we hypothesized that bee colonies housed on combs constructed on small cell foundation would have lower varroa populations and higher adult bee populations and more cm(2) brood. To summarize our results, we found that the use of small cell foundation did not significantly affect cm(2) total brood, total mites per colony, mites per brood cell, or mites per adult bee, but did affect adult bee population for two sampling months. Varroa levels were similar in all colonies throughout the study. We found no evidence that small cell foundation was beneficial with regard to varroa control under the tested conditions in Florida.

Macular oedema is not predicted by perifoveal single blot haemorrhages

AIMS

To ascertain which perifoveal changes on digital retinal screening in diabetes predict the need for subsequent macular grid or focal laser therapy.

METHODS

Between 1 January 2004 and 31 December 2005, all consecutive retinal images where any lesion was within one disc diameter of the fovea were reviewed. Patients were categorized by lesion at screening as having microaneurysm, single blot haemorrhage, multiple blot haemorrhages and exudates or circinate exudates within one disc diameter of the fovea. We compared these retinal images with the findings on slit lamp examination and the related decision for laser photocoagulation.

RESULTS

Four hundred and twenty-four retinal images were identified. Of these, 52 were excluded, principally because of an interval between photography and clinic attendance of greater than 120 days, leaving 372 retinal images in the study group (313 patients). No patients with a single blot haemorrhage required immediate laser therapy at ophthalmology review compared with 13 (23%) of those with multiple blot haemorrhages and 36 (16%) of those with exudates or circinate lesions (P < 0.001). Thirty-nine patients with a single blot haemorrhage who did not require laser therapy underwent ongoing follow-up. None of these underwent laser therapy for maculopathy within the study time frame (9 months from initial screening event).

CONCLUSIONS

In this study, no patients with a single blot haemorrhage within one disc diameter of the fovea on digital retinal screening required laser treatment.

Fear of visual loss in patients with diabetes: results of the prevalence of diabetic eye disease in Tayside, Scotland (P-DETS) study

AIMS

To describe the relationship between fear of visual loss and dependent variables (visual acuity, retinopathy treatment, severity of retinopathy) in community-based diabetic patients.

METHODS

Subjects were identified from the Diabetes Audit and Research in Tayside, Scotland (DARTS) diabetes register. From a total of 4825 individuals known to have diabetes and who were resident in Dundee and Perth (population 216 204; diabetes prevalence 2.23%), 586 persons with diabetes were randomly selected. Participants completed a self-administered questionnaire in Likert grade format which incorporated two items addressing presence and intensity of fear of visual loss.

RESULTS

Questionnaires were returned by 61.4% of the cohort. Fear of visual loss was 'often in mind' for 37% of respondents, and that fear was intense for 47.4%. Analysis by diabetes type revealed differences in reported fear of Type 1 and Type 2 patients in relation to disease and treatment variables. Linear regression highlighted the complexity of the issue with retinal status, acuity and treatment only partly explaining reported patient concern (r(2) range: 0.051-0.125 for presence of fear; 0.026-0.04 for intensity of fear, depending on diabetes type).

CONCLUSIONS

Fear of visual loss is preoccupying and intense for a substantial proportion of the diabetic population. Reasons for this are multiple and complex. Objective measures of visual impairment and retinal status are inadequate predictors of fear. Carers and researchers need to be mindful of this when approaching patients with diabetes.

Dihydroxypyridopyrazine-1,6-dione HIV-1 integrase inhibitors

A series of potent novel dihydroxypyridopyrazine-1,6-dione HIV-1 integrase inhibitors was identified. These compounds inhibited the strand transfer process of HIV-1 integrase and viral replication in cells. Compound 6 is active against replication of HIV with a CIC(95) of 0.31 microM and exhibits no shift in potency in the presence of 50% normal human serum. It displays a good pharmacokinetic profile when dosed in rats and no covalent binding with microsomal proteins in both in vitro and in vivo models.

A potent and orally active HIV-1 integrase inhibitor

A 1,6-naphthyridine inhibitor of HIV-1 integrase has been discovered with excellent inhibitory activity in cells, good pharmacokinetics, and an excellent ability to inhibit virus with mutant enzyme.

Can we predict which patients are at risk of having an ungradeable digital image for screening for diabetic retinopathy?

PURPOSE

We aimed to determine the reasons for, and variables which predicted, ungradeable retinal photographs during screening patients for diabetic retinopathy.

MATERIALS AND METHODS

Age, duration of diabetes, visual acuity, and HbA1c were recorded. Following dark adaptation, a single 45 degrees nonmydriatic photograph was taken of each fundus. The pupils were then dilated and the photograph repeated. Using slit lamp biomicroscopy, lenticular changes (LOCS III), and fundus appearance were recorded.

RESULTS

In ungradeable photographs the fovea could not be visualised in 98% of cases of images from nonmydriatic photography, and in 88% if mydriasis was used. Poor definition in the nonmydriatic image was associated with a subsequent ungradeable mydriatic photograph (P=0.001), however, the positive predictive value was poor (34%). Age, posterior subcapsular cataract, and near vision predicted ungradeable status of nonmydriatic photographs (P<0.001, P=0.004, P=0.006, respectively; regression analysis). Nuclear colour and poor definition of the nonmydriatic photograph predicted ungradeable status of mydriatic photographs (P=0.006 & P=0.001, respectively).

CONCLUSION

Inability to visualise the fovea is the commonest cause of an ungradeable image from digital retinal photography. Age and posterior subcapsular cataract were best predictors of ungradeable status of nonmydriatic fundus photographs. Nuclear colour was the strongest predictor for ungradeable mydriatic photography.

A series of 5-(5,6)-dihydrouracil substituted 8-hydroxy-[1,6]naphthyridine-7-carboxylic acid 4-fluorobenzylamide inhibitors of HIV-1 integrase and viral replication in cells

Introduction of a 5,6-dihydrouracil functionality in the 5-position of N-(4-fluorobenzyl)-8-hydroxy-[1,6]naphthyridine-7-carboxamide 1 led to a series of highly active HIV-1 integrase inhibitors. These compounds displayed low nanomolar activity in inhibiting both the strand transfer process of HIV-1 integrase and viral replication in cells. Compound 11 is a 150-fold more potent antiviral agent than 1, with a CIC(95) of 40 nM in the presence of human serum. It displays good pharmacokinetics when dosed in rats and dogs.

Implementation of national diabetes retinal screening programme is associated with a lower proportion of patients referred to ophthalmology

AIMS

To examine the impact of a new national retinal screening programme on screening attendance, technical quality of images, and referrals to the ophthalmology clinic.

METHODS

Results from the previous ad hoc retinal screening service were compared with data from the first year of the new Scottish Diabetes Retinal Screening Programme in Dundee, which was administered according to criteria recommended by the Health Technology Board Scotland.

RESULTS

Of 5150 patients invited for screening, 10.3% of patients did not attend. Overall, 4574 patients underwent single-field digital retinal photography and 25.4% required mydriasis for an adequate image. After screening, 1.9 and 90.5% were recalled for repeat photography at 6 months and 1 year, respectively, whilst 4.6% were ungradable and 3.0% were referred to the ophthalmology clinic. Compared with the last 18 months of the previous scheme, with the new programme a smaller proportion of patients were referred to ophthalmology (3.0 vs. 5.9%; P < 0.001, difference 2.9%: 95% confidence interval 2.1-3.7%). Moreover, the attendance was higher (89 vs. 82%; P < 0.01) and there were fewer ungradable images (4.6 vs. 7.1%; P < 0.001).

CONCLUSIONS

Introduction of a systematic retinal screening programme can reduce the proportion of patients referred to the ophthalmology clinic, and use ophthalmology services more efficiently.

Frequency and predictors of hypoglycaemia in Type 1 and insulin-treated Type 2 diabetes: a population-based study

AIMS

To ascertain the frequency and identify predictors of self-reported hypoglycaemia in Type 1 and insulin-treated Type 2 diabetes.

METHODS

A random sample of 267 people with insulin-treated diabetes were recruited from a population-based diabetes register in Tayside, Scotland. Each subject prospectively recorded the number of mild and severe hypoglycaemic episodes experienced over a 1-month period. Ordinal logistic regression was performed to identify potential predictors of hypoglycaemia.

RESULTS

Five hundred and seventy-two hypoglycaemic events were reported by 155 patients. The participants with Type 1 diabetes had a total of 336 hypoglycaemic events with a rate of 42.89 events per patient per year. Of these, nine were severe hypoglycaemic events, with a rate of 1.15 events per patient per year. Participants with insulin-treated Type 2 diabetes experienced a total of 236 hypoglycaemic events with a rate of 16.37 events per patient per year. Of these, five were severe hypoglycaemic events, which would be equivalent to 0.35 events per patient per year. Predictors of hypoglycaemia in Type 1 diabetes were a history of previous hypoglycaemia (P = 0.006) and co-prescribing of any oral drug (P = 0.048). In patients with insulin-treated Type 2 diabetes, a history of previous hypoglycaemia (P < 0.0001) and duration of insulin treatment (P = 0.014) were significant predictors.

CONCLUSION

The incidence of self-reported severe hypoglycaemia in insulin-treated Type 2 diabetes is lower than in Type 1 diabetes but does occur more often than previously reported and with sufficient frequency to cause significant morbidity. Duration of insulin treatment is a key predictor of hypoglycaemia in insulin-treated Type 2 diabetes.

Prevalence of diabetic eye disease in Tayside, Scotland (P-DETS) study: methodology

AIMS

To describe the use of a validated diabetes register for sampling frame generation and assessment of the representative nature of participants in a fieldwork study of diabetic eye disease.

METHODS

We performed an observational, cross-sectional fieldwork study of diabetic retinal disease using reference standard eye examination. We sampled the entire diabetic population using the Diabetes Audit and Research in Tayside Study (DARTS) diabetes register.

RESULTS

The study population comprised 4825 diabetic patients aged over 16 years registered with one of 166 general practitioners (GPs) in 41 practices in Tayside in October 1999. This represented 61.1% of the Tayside diabetic population (7903). A total of 586 (66%; 95% confidence interval 63, 70) patients were examined from a sampling frame of 882 living patients registered with a Tayside GP. Demographic and disease parameters recorded on the DARTS patient register allowed comparison between participants and non-participants.

CONCLUSIONS

This study shows the clear benefit of using a complete diabetic population as a sampling frame. This allows potential selection bias and external validity to be evaluated using routine data sources. Studies performed and reported in this way will aid the critical appraisal process.

Effect of mydriasis and different field strategies on digital image screening of diabetic eye disease

AIMS

To assess the effects of (1) mydriasis and (2) single versus three field photography on screening for diabetic eye disease using digital photography

METHOD

Slit lamp examination findings were compared to digital fundal photographs for the detection of any retinopathy and for referable retinopathy in 398 patients (794 eyes). A Topcon TRC-NW6S digital non-mydriatic fundus camera was used. Three photographic strategies were used: undilated single field, dilated single field, and dilated multiple fields. The photographs were presented in random order to one of two retinal screeners. For the single field photographs the screeners were masked to the use of mydriatics. In 13% of fundal photographs, grading was performed by both, rather than just one grader.

RESULTS

Mydriasis reduced the proportion of ungradable photographs from 26% to 5% (p<0.001). Neither mydriasis nor three field photography improved the sensitivity or specificity for the detection of any retinopathy or of referable retinopathy when compared with undilated single field photography. The sensitivity and specificity for detecting referable retinopathy using undilated single field photography was 77% (95% CI 71 to 84) and 95 % (95% CI 93 to 97) respectively. Using dilated single field photography the figures were 81% (95% CI 76 to 87) and 92% (95% CI 90 to 94) respectively. Using dilated three field photography the figures were 83% (95% CI 78 to 88) and 93% (95% CI 91 to 96) respectively. Intergrader reliability for the detection of referable retinopathy in gradable photographs was excellent (Kappa values 0.86-1.00).

CONCLUSIONS

Mydriasis reduces the technical failure rate. Mydriasis and the three field photography as used in this study do not increase the sensitivity or specificity of detecting diabetic retinopathy.

A naphthyridine carboxamide provides evidence for discordant resistance between mechanistically identical inhibitors of HIV-1 integrase

The increasing incidence of resistance to current HIV-1 therapy underscores the need to develop antiretroviral agents with new mechanisms of action. Integrase, one of three viral enzymes essential for HIV-1 replication, presents an important yet unexploited opportunity for drug development. We describe here the identification and characterization of L-870,810, a small-molecule inhibitor of HIV-1 integrase with potent antiviral activity in cell culture and good pharmacokinetic properties. L-870,810 is an inhibitor with an 8-hydroxy-(1,6)-naphthyridine-7-carboxamide pharmacophore. The compound inhibits HIV-1 integrase-mediated strand transfer, and its antiviral activity in vitro is a direct consequence of this ascribed effect on integration. L-870,810 is mechanistically identical to previously described inhibitors from the diketo acid series; however, viruses selected for resistance to L-870,810 contain mutations (integrase residues 72, 121, and 125) that uniquely confer resistance to the naphthyridine. Conversely, mutations associated with resistance to the diketo acid do not engender naphthyridine resistance. Importantly, the mutations associated with resistance to each of these inhibitors map to distinct regions within the integrase active site. Therefore, we propose a model of the two inhibitors that is consistent with this observation and suggests specific interactions with discrete binding sites for each ligand. These studies provide a structural basis and rationale for developing integrase inhibitors with the potential for unique and nonoverlapping resistance profiles.

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.