Selective AKR1C3 inhibitors do not recapitulate the anti-leukaemic activities of the pan-AKR1C inhibitor medroxyprogesterone acetate.

BACKGROUND: We and others have identified the aldo-keto reductase AKR1C3 as a potential drug target in prostate cancer, breast cancer and leukaemia. As a consequence, significant effort is being invested in the development of AKR1C3-selective inhibitors. METHODS: We report the screening of an in-house drug library to identify known drugs that selectively inhibit AKR1C3 over the closely related isoforms AKR1C1, 1C2 and 1C4. This screen initially identified tetracycline as a potential AKR1C3-selective inhibitor. However, mass spectrometry and nuclear magnetic resonance studies identified that the active agent was a novel breakdown product (4-methyl(de-dimethylamine)-tetracycline (4-MDDT)). RESULTS: We demonstrate that, although 4-MDDT enters AML cells and inhibits their AKR1C3 activity, it does not recapitulate the anti-leukaemic actions of the pan-AKR1C inhibitor medroxyprogesterone acetate (MPA). Screens of the NCI diversity set and an independently curated small-molecule library identified several additional AKR1C3-selective inhibitors, none of which had the expected anti-leukaemic activity. However, a pan AKR1C, also identified in the NCI diversity set faithfully recapitulated the actions of MPA. CONCLUSIONS: In summary, we have identified a novel tetracycline-derived product that provides an excellent lead structure with proven drug-like qualities for the development of AKR1C3 inhibitors. However, our findings suggest that, at least in leukaemia, selective inhibition of AKR1C3 is insufficient to elicit an anticancer effect and that multiple AKR1C inhibition may be required.

Cholinergic modulation of midbrain dopaminergic systems.

Dopamine neurons in the midbrain respond to behavioral events and environmental stimuli. Their different patterns of activation in turn modulate the activity of forebrain regions and modulate the expression of selective behavioral responses. However, their activity is closely dependent on the cholinergic systems in the brainstem. Ascending cholinergic projections from the pedunculopontine and laterodorsal tegmental nuclei target dopaminergic neurons in the substantia nigra compacta and ventral tegmental area following a topographical gradient. These projections, by means of the activation of acetylcholine receptors, influence the firing of dopamine neurons and therefore their responsiveness, ultimately affecting the release of dopamine in their forebrain targets. Brainstem cholinergic neurons are thus in a position to critically influence the activity of dopaminergic neurons in the midbrain, and thereby have a critical role in the expression of behavior.

An assessment of the contributions of the pedunculopontine tegmental and cuneiform nuclei to anxiety and neophobia.

The pedunculopontine tegmental and cuneiform nuclei are adjacent structures in the mesopontine tegmentum. The pedunculopontine has attracted interest because of its extensive reciprocal connections with corticostriatal systems and possible role in complex behavioral and cognitive processes; the cuneiform is thought to be part of a neural system important for organizing defensive behaviors. Excitotoxic lesions of the pedunculopontine have been shown to affect a variety of complex functions, including learning and attention, but it has been suggested that a consequence of lesions here is the production of an anxiety-like state. We present experiments to clarify the relative role of the pedunculopontine and cuneiform nuclei in anxiety-like states in rats, measured using the elevated plus maze, food neophobia and palatability tests, and by open field behavior. In addition, we measured (through Fos expression) the effect that being on the elevated plus maze had on the pedunculopontine and cuneiform nuclei. Bilateral ibotenate lesions of cuneiform increased anxiety-like responses on the elevated plus maze, food neophobia and open field tests. Bilateral ibotenate lesions of pedunculopontine that spared cuneiform did not produce anxiety-like behavior, but did disinhibit performance in all the tests. Lesions directed at the pedunculopontine produced anxiety-like effects only when there was also significant damage in the cuneiform. The data are discussed in terms of the relationships these nuclei have with different neural systems: pedunculopontine can be understood in terms of its hierarchical relationships with forebrain systems, while cuneiform is understood best in terms of its role in regulating responses to threatening stimuli.

Fusion of diphtheria toxin and urotensin II produces a neurotoxin selective for cholinergic neurons in the rat mesopontine tegmentum.

Urotensin II is a neuropeptide first isolated from fish and later found in mammals: where it has potent cardiovascular, endocrine and behavioral effects. In rat brain the urotensin II receptor (UII-R) is predominately expressed in the cholinergic neurons of the pedunculopontine (PPTg) and laterodorsal tegmental nuclei. Typically, the function of the PPTg has been examined using excitotoxins, destroying both cholinergic and non-cholinergic neurons, which confounds interpretation. We took advantage of UII-R's unique expression profile, by combining UII with diphtheria toxin, to engineer a toxin specific for cholinergic neurons of the PPTg. In vitro, two different toxin constructs were shown to selectively activate UII-R (average EC50 approximately 30 nmol/L; calcium mobility assay) and to be 10,000-fold more toxic to UII-R expressing CHO cells, than wildtype cells (average LD50 approximately 2 nmol/L; cell viability). In vivo, pressure injection into the PPTg of rats, resulted in specific loss of choline transporter and NADPH diaphorase positive neurons known to express the UII-R. The lesions developed over time, resulting in the loss of over 80% of cholinergic neurons at 21 days, with little damage to surrounding neurons. This is the first highly selective molecular tool for the depletion of mesopontine cholinergic neurons. The toxin will help to functionally dissect the pedunculopontine and laterodorsal tegmental nuclei, and advance the understanding of the functions of these structures.

The Humber Estuary, Eastern England: Strategic planning of flood defences and habitats.

The Humber Estuary Shoreline Management Plan provides a long-term strategy for investment in sustainable defences to reduce the risk to people and property from flooding in part of Eastern England. In addition to the estuary's economic importance with its ports, industry and the third of a million people living on its floodplain, the Humber is of outstanding value for wildlife and its historic environment. The plan has to meet the needs of these activities and take account of rising sea level. It is based on extensive technical studies and modelling. The realignment of some embankments is being examined so that the creation of intertidal habitat will offset losses from coastal squeeze, increase the stability for some lengths of embankment and reduce extreme high flood levels in the tidal rivers. The 80 ha Paull Holme Strays managed realignment wetland was completed in the summer of 2003 and work is in progress on another at Alkborough. Other such realignment will be developed as part of the implementation of the long term strategy.

Issues in high-throughput comparative modelling: a case study using the ubiquitin E2 conjugating enzymes.

Sequences of the ubiquitin-conjugating enzyme (UBC or E2) family were used as a test set to investigate issues associated with the high-throughput comparative modelling of protein structures. A semi-automatic method was initially developed with particular emphasis on producing models of a quality suitable for structural comparison. Structural and sequence features of the E2 family were used to improve the sequence alignment and the quality of the structural templates. Initially, failure to correct for subtle structural inconsistencies between templates lead to problems in the comparative analysis of the UBC electrostatic potentials. Modelling of known UBC structures using Modeller 4.0 showed that multiple templates produced, on average, no better models than the use of just one template, as judged by the root-mean-squared deviation between the comparative model and crystal structure backbones. Using four different quality-checking methods, for a given target sequence, it was not possible to distinguish the model most similar to the experimental structure. The UBC models were thus finally modelled using only the crystal structure template with the highest sequence identity to the target to be modelled, and producing only one model solution. Quality checking was used to reject models with obvious structural anomalies (e.g., bad side-chain packing). The resulting models have been used for a comparison of UBC structural features and of their electrostatic potentials. The work was extended through the development of a fully automated pipeline that identifies E2 sequences in the sequence databases, aligns and models them, and calculates the associated electrostatic potential.

An examination of d-amphetamine self-administration in pedunculopontine tegmental nucleus-lesioned rats.

The pedunculopontine tegmental nucleus (PPTg) has long been suggested to have a role in reward-related behaviour, and there is particular interest in its possible role in drug reward systems. Previous work found increased i.v. self-administration (IVSA) of d-amphetamine following PPTg lesions when training had included both operant pre-training and priming injections. The present study examined the effect of excitotoxin lesions of the PPTg on d-amphetamine IVSA under three training conditions. Naive: no previous experience of d-amphetamine or operant responding. Pre-trained: given operant training with food before lesion surgery took place. Primed: given single non-contingent d-amphetamine infusion (0.1 mg/0.l ml) at the start of each session. Rats in all conditions were given either ibotenate or phosphate buffer control lesions of the PPTg before d-amphetamine (0.1 mg/0.1 ml infusion) IVSA training took place. Rats received eight sessions of training under a fixed ratio (FR2) schedule of d-amphetamine IVSA, followed by four sessions under a progressive ratio (PR5) schedule. In the naive condition, PPTg-lesioned rats were attenuated in their responding under FR2, and took significantly fewer infusions under PR5 than the control group. Under FR2 in the pre-trained condition, there was no difference between PPTg excitotoxin and control lesioned rats; however, PPTg-lesioned rats took significantly fewer infusions under the PR5 schedule. In the primed condition, there were no differences between PPTg-lesioned and control rats under either FR2 or PR5 schedules. These data demonstrate that operant training prior to PPTg lesion surgery corrects some, but not all, of the deficits seen in the naive condition. PPTg-lesioned rats in both naive and pre-trained conditions showed reduced responding for d-amphetamine under a PR5 schedule. These deficits are overcome by priming with d-amphetamine. We suggest that alterations in striatal dopamine activity following PPTg lesions underlie these effects.

Planning for the rising tides: the Humber Estuary Shoreline Management Plan.

The Humber Estuary Shoreline Management Plan provides the framework for investment in defences to reduce the risk of flooding to people, property and the environment. A key issue is the rise in sea level, which is reducing the standard of protection provided and is increasing erosion. The plan is developed from detailed geomorphological and ecological studies, and extensive consultation with interested organisations and the community. It takes into account the urban and industrial development on the floodplain, high-grade agricultural land, the historic environment and the Humber's status as an outstanding site for wildlife, which is protected under the Habitats Directive. A key aim is wherever possible to work with natural processes. Another is to ensure that there is no net loss of protected inter-tidal habitat. The options investigated include changes to the existing alignment of the embankments. The overall strategy provides for a continuing line of defence around the estuary and tidal rivers but with the use of managed retreat in some places. The creation of new inter-tidal habitat by this means is to gain more stable and cost-effective defences, and to offset the loss of protected sites, including by coastal squeeze. Further studies are in progress to appraise potential managed retreat sites.

Behavioural sensitisation to repeated d-amphetamine: effects of excitotoxic lesions of the pedunculopontine tegmental nucleus.

The pedunculopontine tegmental nucleus (PPTg) interacts with anatomical systems thought to be involved in mediating sensitisation of the locomotor response to repeated d-amphetamine. The PPTg has direct and indirect connections with the nucleus accumbens and prefrontal cortex, and also influences midbrain dopamine activity through direct projections to substantia nigra and ventral tegmental area. In this experiment, the development of behavioural sensitisation to the locomotor stimulant effects of repeated d-amphetamine was examined in rats bearing excitotoxic lesions of the PPTg, and sham-lesioned controls. Rats were given repeated d-amphetamine (1.5 mg/kg i.p.) treatment in an on-off procedure, with saline and d-amphetamine given on alternate days, such that rats received a total of seven d-amphetamine and seven saline treatments. Locomotor responses were measured in photocell cages. On the first day of d-amphetamine treatment, there was no difference between excitotoxin and sham-lesioned rats. Development of sensitisation to the locomotor stimulant effects of d-amphetamine was delayed in PPTg-lesioned rats, relative to the sham-lesioned control rats. However, there was no difference between lesion and control groups in the locomotion seen on saline-treatment days. These data suggest that the PPTg is involved in the development of behavioural sensitisation to the locomotor stimulant effects of repeated d-amphetamine, and indicate that traditional striatal circuitry models of the mechanisms underlying sensitisation should be extended to include the PPTg.

Examination of the role of the pedunculopontine tegmental nucleus in radial maze tasks with or without a delay.

Two radial maze tasks, random foraging and delayed spatial win-shift, have been used to investigate, in rats, the functions and inter-relationships of structures connected through the corticostriatal loops, such as the prelimbic cortex, nucleus accumbens, ventral pallidum and mediodorsal thalamus. The random foraging task is designed to investigate animals' ability to use spatial information to guide foraging on-line. The delayed spatial win-shift task requires, in addition, that animals hold spatially relevant information in working memory across a delay period. The pedunculopontine tegmental nucleus receives direct output from ventral striatal systems and might therefore be expected to share functional properties with them. In the present experiments we have examined the performance of rats bearing bilateral excitotoxic lesions of the pedunculopontine tegmental nucleus on both of these tasks. In acquisition tests rats were given bilateral lesions before any training took place, while in retention tests appropriate training to predetermined criterion levels of performance took place before lesions were made. In both tasks, and in both acquisition (no prelesion training) and retention (prelesion training) tests, rats with pedunculopontine lesions made significantly more errors in selecting arms to enter than did control rats. There was no motor impairment present in pedunculopontine tegmental nucleus-lesioned rats - on the contrary, on measures of speed (latency to make first arm choice and the mean time for subsequent choices) pedunculopontine-lesioned rats were slightly faster than control rats. We suggest that the pedunculopontine tegmental nucleus shares functional properties with frontostriatal systems and that it forms part of a brainstem-directed stream of striatal outflow different to the cortical re-entrant system via the thalamus.

The effect of excitotoxic lesions of the pedunculopontine tegmental nucleus on performance of a progressive ratio schedule of reinforcement.

The pedunculopontine tegmental nucleus has connections with sites in both dorsal and ventral striatum, and a number of studies have suggested that it has a role in reward-related behaviour. The present experiment aimed to investigate the perception of reward in pedunculopontine tegmental nucleus-lesioned rats responding for food under a progressive ratio schedule, which measures willingness to work for a given reward. Rats were trained on a progressive ratio-5 schedule for food reward, then given ibotenic acid or sham lesions of the pedunculopontine tegmental nucleus. Their performance under this schedule was examined again following recovery from surgery. Compared with sham-lesioned rats, those with lesions of the pedunculopontine tegmental nucleus showed significantly reduced breaking points and significantly longer post-reinforcement pauses. However, there was no difference between the groups in their latency to collect food pellets once earned, suggesting that pedunculopontine tegmental nucleus excitotoxin and sham-lesioned rats were equally motivated by the presence of food. Excitotoxin-lesioned rats made significantly more responses on the control lever and more entries to the food hopper as progressive ratio increment increased, but did not differ from controls when the schedule requirement was low. These results are interpreted as indicating no global loss of motivation, since lesioned rats performed normally at low schedule requirements, and were as fast as controls to collect pellets. But as the schedule requirement increased, excitotoxin-lesioned rats showed reductions in responding on the active lever (that is, a reduction in breaking point) and an increase in inappropriate responses towards the food hopper and the control lever.We consider these data to indicate that the behavioural deficits in pedunculopontine-lesioned rats arise not from a sensory or hedonic change, but from alteration in the control of motor output.

Update on nursing home care in Oklahoma.

In Oklahoma approximately 36,000 people live in a nursing home. This article reviews those initiatives by Medicare, the Health Care Finance Administration (HCFA), and the American Medical Directors' Association to improve the quality of care that physicians and nurses provide to residents in long-term care facilities, specifically nursing homes.

Ventral mesopontine projections of the caudomedial shell of the nucleus accumbens and extended amygdala in the rat: double dissociation by organization and development.

The shell of the nucleus accumbens and central division of the extended amygdala are telencephalic structures that influence motor activity and lately have been regarded by some as components of a single functional-anatomic continuum. Each has a highly differentiated internal organization and output system and distinct pharmacologic responses however, and it is thus likely that each subserves distinct contributions to behavior. In this investigation, nucleus accumbens and extended amygdala outputs were compared by using retrograde tracing in adult and postnatal rats. Fluoro-Gold, when injected into the ventral tegmental area, produced substantial retrograde labeling in the adult nucleus accumbens shell, but only trivial amounts in the central division of the extended amygdala. Injection sites in the lateral mesopontine tegmentum produced robust labeling in the central extended amygdala but little in the nucleus accumbens. The projections of extended amygdala were substantially developed by postnatal day 1, whereas those of the caudomedial shell of the nucleus accumbens only reached the ventral tegmental area by approximately postnatal day 6. Few neurons projecting from the caudomedial shell of the accumbens to the ventral tegmental area were observed even at postnatal day 21. In consideration of the reported importance of the nucleus accumbens, particularly the caudomedial shell, in neural processing related to reward and motivation and the central nervous system response to antipsychotic drugs, it may be important to determine whether processes occurring during the protracted postnatal development of the caudomedial shell are vulnerable to destructive circumstances, such as drug intoxication, maternal separation, or social isolation.

The effects of excitotoxic lesions of the pedunculopontine tegmental nucleus on conditioned place preference to 4%, 12% and 20% sucrose solutions.

A number of studies have suggested that the pedunculopontine tegmental nucleus (PPTg) may play a role in reward-related behaviour. The present study was intended to investigate this further using conditioned place preference. In conditioned place preference paradigms the amount of time spent in a preferred environment is proportional to the value of the reinforcement present, until a maximum is reached. In the present experiments we aimed to determine whether this relationship was affected by lesions of the PPTg by examining the formation of a conditioned place preference to either 4%, 12% or 20% sucrose solutions in food-deprived PPTg lesioned rats. The conditioned place preference apparatus had two compartments different in colour, smell and floor texture. During conditioning, rats were restricted to one compartment or the other, one of which was paired with sucrose. This was carried out during 30 min sessions, alternating conditioned or nonconditioned trials for 14 days. On the test day, rats were given access to both compartments through a connecting chamber, and were scored for side preference over 15 min. Both PPTg and sham lesioned rats showed a conditioned place preference to 12% and 20% sucrose, but no place preference was formed by either group to 4% sucrose. There was no significant difference between the groups in the place preference shown. Consumption of 4% sucrose was not affected by excitotoxic lesions of the PPTg, but PPTg lesioned rats consumed significantly more 12% and 20% sucrose than sham controls. This suggests that perception of reward value, as judged by CPP formation, is unchanged by excitotoxic lesions of the PPTg. The increased consumption of 12% and 20% sucrose shown by rats bearing such lesions is therefore not likely to be a product of altered reward perception.

Medication administration hassles reported by family caregivers of dependent elderly persons.

BACKGROUND: Even under the new long-term care mantra for increased home- and community-based care options, attention to and an understanding of the ways that family caregivers are managing complex care for dependent elderly persons, for example, with medication administration, have been slow to materialize. METHODS: Twenty-three family caregivers completed semistructured, face-to-face interviews to capture the shared and idiosyncratic experiences of individuals responsible for all aspects of medication administration regimens for elderly, dependent family members. Data analysis consisted of content analysis of the verbatim interview transcripts. This article reports an emerging typology of caregiver medication administration hassles derived from the interviews. RESULTS: Based on 122 separate accounts, three categories of medication administration hassles were identified. The categories (with the percentage of all accounts represented by the category) include (i) scheduling logistics (29.5%), (ii) administration procedures (31.9%), and (iii) safety issues (38.6%). CONCLUSIONS: Primary care providers must continually reevaluate and simplify medication regimens for dependent elderly persons in the care of family members, and the family caregivers must be given adequate training and access to ongoing information support systems to help them perform safe and effective medication administration responsibilities.

Self-organizing molecular field analysis: a tool for structure-activity studies.

Self-organizing molecular field analysis (SOMFA) is a novel technique for three-dimensional quantitative structure-activity relations (3D-QSAR). It is simple and intuitive in concept and avoids the complex statistical tools and variable selection procedures favored by other methods. Our calculations show the method to be as predictive as the best 3D-QSAR methods available. Importantly, steric and electrostatic maps can be produced to aid the molecular design process by highlighting important molecular features. The simplicity of the technique leaves scope for further development, particularly with regard to handling molecular alignment and conformation selection. Here, the method has been used to predict the corticosteroid-binding globulin binding affinity of the "benchmark" steroids, expanded from the usual 31 compounds to 43 compounds. Test predictions have also been performed on a set of sulfonamide endothelin inhibitors.

A practical approach to managing community dwellers with Alzheimer's disease.

This article will review multiple strategies and treatment options that can be utilized by clinicians to address the ever-changing and varied needs of community dwelling elders with Alzheimer's disease and those of their families. Comprehensive assessment and the judicious use of medications, together with other nonpharmacological interventions, may lessen the burden of care on families and decrease the likelihood of institutionalization.

Long-lived picture priming in normal elderly persons and demented patients.

Normal elderly control participants showed short-term (10-min delay) and long-term (12 months delay) priming on the Gollin Figures Test. Nearly all patients with Alzheimer's disease or vascular dementia showed short-term priming, but the magnitude of their priming was less than that of controls. Significant long-term priming was not observed for the dementia groups. Differences between controls and dementia patients on the short-term priming test may depend upon structural-perceptual processes that are intact in dementia patients and controls and explicit memory functions available only to controls. The same model could account for differences between normal elderly and dementia patients on the long-term priming test, but several other explanations are also plausible.