The effect of steady-state ropinirole on plasma concentrations of digoxin in patients with Parkinson's disease

AIMS

The aim of this single-blind study was to assess the effect of ropinirole, a novel treatment for Parkinson's disease, on the steady-state pharmacokinetics and safety of digoxin in 10 patients with Parkinson's disease.

METHODS

There were three parts to the study: digoxin once daily plus placebo three times daily for 1 week; digoxin once daily plus ropinirole three times daily for 6 weeks; and digoxin once daily plus placebo three times daily for 1 week. Serial blood samples were collected over 24 h at the end of each part of the study for pharmacokinetic assessment. Pre-dose blood samples were collected on specific days throughout the study to assess the attainment of steady-state plasma levels of digoxin. The primary endpoints were AUC(0, tau) and Cmax for digoxin.

RESULTS

There was a mean decrease of 10% in digoxin AUC (0, tau) (90% CI: 0.79, 1.01) and a 25% decrease in digoxin Cmax (90% CI: 0.58, 0.97) when ropinirole was co-administered, compared with digoxin alone Cmin plasma values for digoxin, however, were fairly constant throughout the study (point estimates 0.99, 95% CI: 0.85, 1.15). Changes in trough levels of digoxin are believed to be the most reliable way of assessing steady-state concentrations of digoxin, and therefore the clinical significance of an interaction. Changes in Cmax are too readily influenced by other factors.

CONCLUSIONS

These results therefore indicate that on pharmacokinetic grounds no dose adjustment is necessary for digoxin co-administered with ropinirole.

Ubiquitin-dependent pathway is up-regulated in differentiating lens cells

The mammalian eye lens is composed of two distinct types of cells, epithelial cells and fiber cells. The fiber cells are generated throughout life via continuous differentiation of epithelial cells. Differentiation of lens cells involves dramatic changes in cellular components including altered activity of the ubiquitin dependent pathway. The concentration of high mass ubiquitin conjugates in the mitotically active-, differentiating-equatorial epithelial cells was 5-10 fold higher than that observed in mitotically quiescent, non-differentiated, central epithelial cells, even though there was a significant dilution of non-crystallin proteins due to an increase in level of crystallins in the differentiating cells. Similar observations were made when differentiation was modeled by exposure of lens epithelial explants to bFGF in culture. Activities of ubiquitin-activating enzyme (E1) and ubiquitin-conjugating enzymes (E2s) in the differentiating equatorial epithelial cells were also up to 100% higher than those noted in non-differentiated central epithelial cells and E1 appears to be rate controlling for ubiquitinylation. Consistent with the higher concentrations of high mass ubiquitin conjugates, there was a trend of enhanced ability to execute ATP-dependent protein degradation in the differentiating equatorial epithelial cells as compared with degradation in the non-differentiated central epithelial cells. These data indicate that the ubiquitin dependent pathway is up-regulated during differentiation of lens cells. In the differentiated fibers, the concentration of high mass ubiquitin conjugates and relative activities of E1 and E2s were 50% lower than in the non-differentiated central epithelial cells. In comparison, the concentration of the 110 kDa E1 was unchanged in differentiated fibers. However, if the factor of dilution by the significant increase in the level of crystallins was taken into account, the level or activities of the components of ubiquitin pathway in the differentiated cells was higher than the level noted in non-differentiated cells. These data indicate that, as compared with other non-crystallin proteins, there is differential stabilization and/or synthesis of the 110 kDa E1 and some other components of the ubiquitin dependent pathway in differentiated fibers.

A pilot controlled family study of DSM-III-R and DSM-IV ADHD in African-American children

BACKGROUND

Very little is known about attention-deficit hyperactivity disorder (ADHD) in African-American children, and although the familial transmission of ADHD has been well established in white samples, prior work has not evaluated this feature of ADHD in African-American families.

METHOD

Subjects were 37 first-degree relatives of children with DSM-III-R-defined ADHD and 52 first-degree relatives of non-ADHD comparison children matched for ethnicity, age, and gender. DSM-III-R-based structured interviews (modified to include DSM-IV diagnoses) provided the basis for psychiatric diagnoses in relatives.

RESULTS

The risks for both DSM-III-R and DSM-IV ADHD were significantly greater in first-degree relatives of ADHD probands than in relatives of controls. In addition, the relatives of ADHD probands also were at higher risk for oppositional defiant disorder, antisocial personality disorder, major depression, generalized anxiety, and substance use disorders.

CONCLUSIONS

These results suggest that ADHD and related disorders are familial in African-Americans. Further work is needed to confirm the familial transmission of ADHD in African-American children and to explore the role of genetics as well as environmental factors in the transmission of the disorder.

Antecedents and complications of trauma in boys with ADHD: findings from a longitudinal study

OBJECTIVE

To examine the relationship between trauma and attention-deficit hyperactivity disorder (ADHD), evaluating whether ADHD increases the risk for trauma, the risk for posttraumatic stress disorder (PTSD), or the risk for trauma-associated psychopathology.

METHOD

Data from a longitudinal sample of 260 children and adolescents with and without ADHD were examined. All were evaluated comprehensively with assessments in multiple domains of functioning including systematic assessments of trauma and PTSD. Comparisons were made between traumatized and nontraumatized youths with and without ADHD.

RESULTS

No meaningful differences were detected in comparisons between ADHD and control children, either in the rate of trauma exposure or in the development of PTSD. Although trauma was associated with the development of major depression, this effect was independent of ADHD status. In contrast, bipolar disorder at baseline assessment was a significant risk factor for subsequent trauma exposure.

CONCLUSIONS

ADHD was not found to be a risk factor for either trauma exposure or PTSD, but childhood mania was. If confirmed, this finding stresses the potential severe clinical sequelae of childhood mania in children.

The role of dual energy x-ray absorptiometry in aiding the diagnosis of pediatric osteogenesis imperfecta

The role of dual energy x-ray absorptiometry (DEXA) in the evaluation of the pediatric patient with multiple fractures has not been well established. We retrospectively examined the medical records of 45 patients who had presented to our institution with multiple fractures of unknown cause, who were not known to have osteogenesis imperfecta, and who had obtained DEXA as part of their evaluation. Of these, 26 patients had sufficient clinical data for inclusion in this study. Patients underwent DEXA of the anteroposterior spine and whole body. A z score was calculated to normalize the DEXA values for age. The diagnosis of osteogenesis imperfecta was correlated with the outcome of each DEXA scan to assess the validity of DEXA as a diagnostic tool. The DEXA of the anteroposterior spine had the highest sensitivity at 91.7%, while DEXA of the whole body had the highest specificity at 100.0%. Decreased bone mineral density may be associated with osteogenesis imperfecta, and DEXA is helpful in detecting low bone mineral density that may be missed on plain radiographs of children with milder forms of osteogenesis imperfecta.

The influence of stereoisomerism on the pharmacokinetics of Tc radiopharmaceuticals

The influence of stereoisomerism on the pharmacokinetics of Tc mono-oxo complexes is reviewed. Tc(V) monooxo complexes formed with N/S ligands have four donor groups from the ligands in an equatorial plane; the oxo ligand coordinates in an axial position. Stereoisomerism in Tc (V) mono-oxo complexes can be centered within the ligand (carbon atom in the chelate ring or ligating nitrogen of amine donors) or at the Tc. The metal center becomes chiral when an equatorial ligand has a head and a tail (i.e., the two ends of the ligand differ). All types of stereocenters can produce significantly different pharmacokinetic profiles for individual isomers. Thus, biological evaluation of separated stereoisomers is necessary to identify the optimal sterochemical configuration, particularly for radiopharmaceuticals targeted to receptor molecules with low specificity. Because of interspecies variation, there is ultimately no substitute for human testing. Although it is possible that the increase in non-specific binding of agents incorporating L-vs D-amino acids may more than offset any increased receptor binding, much more information is needed. Stereochemical factors can also lead to unpredictable differences in coordination geometry and thermodynamic preference of a single isomer; thus chemical characterization of stereoisomers continues to be an important component of radiopharmaceutical development.

Discriminative stimulus properties of the atypical neuroleptic clozapine in rats: tests with subtype selective receptor ligands

The interoceptive stimulus induced by clozapine (5 mg/kg, i.p.) has been characterized in an operant drug discrimination procedure in the rat using a wide range of receptor subtype-selective agonists and antagonists. Only the muscarinic receptor antagonist scopolamine generalized fully to clozapine (>80%). Partial generalization (defined here as 40% maximal generalization) was seen with the D1 receptor antagonist SCH 23390 (43% maximal generalization), the alpha1-adrenoceptor antagonist prazosin (67%) and the alpha2-adrenoceptor antagonist methoxyidazoxan (42%). All other specific agents tested induced <25% maximal generalization, including the alpha2-adrenoceptor antagonist yohimbine (24%), the histamine H1 receptor antagonist mepyramine (21%), the D2 antagonist typical neuroleptic haloperidol (23%), the D4 receptor antagonist L-745,870 (14%), the 5-hydroxytryptamine-1A (5-HT1A) receptor agonist S-14506 (8%), the 5-HT2A receptor antagonists ketanserin (0%) and M100907 (12%), the 5-HT2B/2C receptor antagonists SB 200646A (8%) and SDZ SER 082 (6%), and the 5-HT3 receptor antagonist ondansetron (0%). The clozapine discriminative stimulus was not blocked by the dopamine D1 receptor antagonist SCH 23390, or by the 5-HT1A receptor antagonist WAY 100635, when given concomitantly with clozapine. Although the results suggest that muscarinic antagonism plays a major role in the clozapine cue, the results have to be considered in the light of the full generalization to clozapine seen with various antipsychotic agents which have very low affinity for muscarinic receptors, including zotepine, quetiapine, JL13 and PNU 96415 (a finding replicated in rats from the same breeding colony as those which generalized to scopolamine). Thus, generalization to clozapine for antipsychotics with multiple affinities but with low muscarinic affinity is probably mediated by additive or perhaps supra-additive actions at other receptors, although extensive studies with various combinations of drug mixtures are required to validate this hypothesis.

The multistep process of homotypic neutrophil aggregation: a review of the molecules and effects of hydrodynamics

Homotypic adhesion of neutrophils stimulated with chemoattractant is analogous to capture on vascular endothelium in that both processes are supported by L-selectin and beta 2-integrin adhesion receptors. Under hydrodynamic shear, cell adhesion requires that receptors bind sufficient ligand over the duration of intercellular contact to withstand the hydrodynamic stresses. Using cone and plate viscometry to apply a uniform linear shear field to suspensions of neutrophils and flow cytometry to quantitate the size distribution of aggregates formed over the time course of formyl peptide stimulation, we conducted a detailed examination of the affect of shear rate and shear stress on the kinetics of cell aggregation. The efficiency of aggregate formation was fit from a mathematical model based on Smoluchowski's two-body collision theory. Over a range of venular shear rates (400-800 s-1), approximately 90% of the single cells are recruited into aggregates ranging from doublets to grouping larger than sextuplets. Adhesion efficiency fit to the kinetics of aggregation increased with shear rate from approximately 20% at 100 s-1 to a maximum level of approximately 80% at 400 s-1. This increase to peak adhesion efficiency was dependent on L-selectin and beta 2-integrin, and was resistant to shear stress up to approximately 7 dyn/cm2. When L-selectin was blocked with antibody, beta 2-integrin (CD11a,b) supported adhesion at low shear rates (< 400 s-1). Aggregates formed over the rapid phase of aggregation remain intact and resistant to shear up to 120 s. At the end of this plateau phase of stability, aggregates spontaneously dissociate back to singlets. The rate of cell disaggregation is linearly proportional to the applied shear rate. The binding kinetics of selectin and integrin appear to be optimized to function within discrete ranges of shear rate and stress, providing an intrinsic mechanism for the transition from neutrophil tethering to firm but reversible adhesion.

Calorie restriction, stress and the ubiquitin-dependent pathway in mouse livers

Calorie restriction (R) is the only known method to delay the aging process and extend mean and maximal lifespan in rodents. R has been shown to delay the age-related accumulation of damaged proteins and to protect organisms from various stresses which can produce damaged proteins. Such stresses include irradiation, heat shock, and oxidative stress. The ubiquitin- and ATP-dependent proteolytic pathway (UPP) has been associated with the degradation of abnormal and/or damaged proteins. We examined the effect of diet and oxidative stress on activities of the UPP in supernatants from livers taken from 23-month-old Emory mice which had been exposed to an in-vivo injection of paraquat. Paraquat induces oxidative stress by generating superoxide radicals. In livers from non-stressed animals, steady-state levels of endogenous ubiquitin conjugates, de novo conjugate formation, and E1 and E2 activities were significantly lower in R animals than in control (C) animals. However, after exposure to paraquat, levels of endogenous ubiquitin conjugates were significantly higher in R versus C animals, and de novo conjugate formation and E1 and E2 activities in R animals rose to levels which were indistinguishable from levels of these activities noted in C animals. R was associated with an increased ability to degrade beta-lactoglobulin by the UPP after an oxidative stress was imposed. Ability to degrade beta-lactoglobulin by the C or R livers in non-stressed animals was not significantly different. Taken together, these data indicate that oxidative stress in R animals is associated with enhanced levels of ubiquitin conjugates and that this enhancement may be due to an increase in UPP activity. These data also indicate that the ability to form ubiquitin conjugates and the UPP system does not change with oxidative stress in C animals. The latter is consistent with prior reports that suggests that older C animals may already be in a state of enhanced oxidative stress and that activities of the UPP provide a sensitive indicator of levels of cellular redox status.

Lessons to be learned: a case study approach. An unusual case of alveolar deposition from swallowing metallic mercury in an attempt at self-poisoning

The authors report a case of deliberate self-poisoning in a drug addict who swallowed elemental mercury: in so doing he inadvertently acquired a permanent diffuse deposition of mercury particles throughout both lung fields. Swallowed mercury should be relatively harmless in small quantity but the high specific gravity and free flowing properties of elemental mercury allowed it to overcome the normal swallowing pathways--such that some of it passed into the bronchial tree instead of passing harmlessly through the gut. In that site its significant vapour pressure, together with its potential for oxidation to inorganic mercury--which may, in turn, be absorbed across the alveolar membrane, gives high potential for mercury poisoning.

Diabetes complications and risk factors in an Australian population. How well are they managed?

BACKGROUND

This study aimed to explore the relationship between complications and risk factors in the type 2 diabetes population, and to assess the level of assistance people with diabetes receive in controlling their risk factors.

METHODS

Participants were recruited from representative population surveys of South Australians aged over 18 years. Participants were asked a series of questions about their risk factors and the advice and assistance they received from their general practitioner (GP) in modifying their risk factors. Additionally, participants were clinically tested for a number of macro and microvascular complications.

RESULTS

South Australians with type 2 diabetes have a high prevalence of risk factors, with the majority being overweight or obese, doing no vigorous exercise and having high blood pressure. They also have a high prevalence of complications, with 53% having at least one macrovascular complication and 66% having at least one microvascular complication. Additionally, participants reported high levels of GP advice and assistance on the risk factors where pharmacological controls were available, but low levels of assistance where non-pharmacological interventions were needed to control the risk factor.

CONCLUSIONS

The prevalence of diabetes risk factors and complications among South Australians with type 2 diabetes is a cause for concern, as is the lack of assistance offered by GPs to modify risk factors. Multi-disciplinary approaches to the control of risk factors and patient self-management and education are critical to the progression and success of diabetes care.

The effects of aging and calorie restriction on plasma nutrient levels in male and female Emory mice

We examined the effect of diet, age (4.5, 13 and 23 months), and sex on plasma levels of retinol, tocopherol, ascorbate, cholesterol, glucose and glycohemoglobin in male and female Emory mice which were fed control (C) and 50% calorie restricted (R) diets. Results showed that C fed animals tended to have higher levels of plasma ascorbate (50-71%), cholesterol (23-71%), glucose (38-81%) and glycohemoglobin (50%). However, these diet differences varied with the age and sex of the animals. Plasma retinol levels were lower only in R males vs. C males (50%). Novel sex-related differences in levels of plasma retinol (2-fold higher in C male mice than in C or R female mice) are described. Aging was associated with trends towards lower levels of plasma ascorbate (14-25%), glucose (34-36%) and glycohemoglobin (47-57%) from 4.5 to 23 months of age. However, these age differences depended upon the diet and sex of the animals. These data suggest that lower plasma levels of glucose, glycosylated hemoglobin and cholesterol may be causally related to the life extension noted in R animals since elevated levels of these moieties have been related to aging. Since oxidative stress is thought to be causally related to aging it appears unlikely that retinol, tocopherol and ascorbate are causally related to R-induced life-extension.

Impact of the prehospital trauma life support programme in Trinidad and Tobago

The impact of the Prehospital Trauma Life Support (PHTLS) programme, introduced in Trinidad and Tobago in 1992, was assessed by questionnaires completed by 26 medical personnel (MP); 71 ambulance personnel (AP); and 50 non ambulance paramedical personnel (NAP). Of the 23 MP, 45 AP and 38 NAP who were aware of the programme, 19 (82.6%) MP, 40 (88.9%) AP and 25 (65.8%) NAP were able to differentiate personnel that had taken the PHTLS programme based on their performance. 32 (71.1%) of the AP were PHTLS trained. 24 (53.3%) and 4 (9%) of the AP identified poor equipment and poor supervision, respectively, as reasons for difficulty in applying PHTLS principles. Improvements observed among those completing the PHTLS programme were: improved resuscitation techniques by 20 (86.9%) MP, 38 (84.4%) AP and 27 (71.1%) NAP; better vital signs recording by 8 (34.8%) MP, 27 (60%) AP and 8 (21.1%) NAP; improved immobilization by 23 (100%) MP, 40 (88.9%) AP and 33 (86.8%) NAP; better haemorrhage control by 22 (95.6%) MP, 40 (88.9%) AP and 24 (63.2%) NAP; appropriate splinting of fractures by 23 (100%) MP, 40 (88.9%) AP and 32 (84.2%) NAP; and increased utilization of oxygen by 15 (65.2%) MP, 31 (68.9%) AP and 21 (55.3%) NAP. 32 (71.1%) AP with PHTLS training indicated improvement in their ability to resuscitate and transport trauma victims, with 42 (93.3%) reporting improvement in overall prehospital care. Medical, paramedical and ambulance personnel all perceive a significant positive impact of PHTLS training on prehospital trauma care. Although improvements in supervision, documentation and equipment are still required, improved trauma resuscitative techniques after PHTLS training should improve trauma patient outcome in Trinidad and Tobago.

Tetanus--the silent killer: how safe are you?

Despite the fact that tetanus is entirely preventable, mortality and morbidity as a result of this disease remain significant. The tetanus toxoid is one of the most potent poisons known. While immunisation programs focus on children, the elderly remain at risk of contracting immunisable diseases. Tetanus often leads to prolonged hospital stays and requires emergency and intensive care intervention and management. This case study illustrates a number of important points concerning the recognition, treatment, management and prevention of tetanus poisoning, and highlights the importance of considering the immunisation status of our elderly patients.

Neuropsychologic aspects of multiple sclerosis

The psychological well being of the patient and the patient's entire family is critically important to successful rehabilitation of individuals with multiple sclerosis (MS). This article deals with the psychotherapeutic management and problems faced by the person with MS, including fatigue, chronic pain, stressful life events, and cognitive defects.

Influence of barrier occlusiveness on guided bone augmentation. An experimental study in the rat

The present study was designed to test perforated and non-perforated barriers for their ability to promote augmentation of bone tissue. More specifically, 1 totally occlusive barrier and 6 barriers with perforation sizes of about 10, 25, 50, 75, 100, and 300 microns and 1 group with no barriers placed (open test chambers) were used to test the effect of a barrier's occlusiveness on the amount and composition of augmented tissue over time. The skull of the rat was used as the experimental area. Prefabricated, flexible silicone frames with an inferior flange for peripheral sealing to the bone surface and a central vertical through hole with a diameter of 3.6 mm and a height of 2 mm were used as test chambers. The barriers were inserted to cover the superior opening of the through hole. The healing periods were 4, 8, and 12 weeks. All test chambers exhibited newly formed skull bone which was augmented over time. The placement of totally occlusive barriers resulted in the slowest rate of bone tissue augmentation but in a highly predictable manner, i.e., there were only small individual variations. Placement of barriers with perforations exceeding 10 microns, on the other hand, resulted in a faster rate of bone augmentation with larger individual variations and a totally different augmentation pattern. A pronounced augmentation of calvarial soft tissue from the sagittal suture of the skull as well as ingrowth of suprabony connective tissue through the barriers were also observed. After 12 weeks of healing, no differences in the amount of augmented mineralized bone related to perforation sizes > 10 microns were found. The open test chambers also showed bone augmentation, although most of their volume was occupied by suprabony connective tissue.

Patient perceptions of hospital care: building confidence, faith and trust

AIM

The aim of this study was to understand how people evaluate and make sense of their experience of hospital care.

METHOD

Narrative interviews were conducted with 18 patients between 4-6 weeks after an episode of inpatient care or day surgery. Participants were deliberately sampled from a population who participated in a hospital-wide audit which took place during 1 week in June 1995. Sampling criteria ensured a mix of age, gender, type of, and reason for, admission. The interviews were audiotaped, transcribed and analysed using grounded theory.

FINDINGS

Three categories: 'feeling informed', 'valued as an individual', and 'at home' contributed to a core category: 'building confidence, faith and trust'. Notably, confidence and trust were determined as much by observations of the care given to other people, as the care the participants themselves had received.

CONCLUSIONS

More attention needs to be given to understanding the complex social and reflective process which underpin patient judgements about quality of care.

Guidelines for the use of imaging techniques for the investigation of venous thromboembolic disease

The diagnosis of venous thromboembolic disease remains a difficult challenge. Chest radiography, ventilation/perfusion lung scanning, noninvasive leg testing, and pulmonary angiography were evaluated with regard to sensitivity, specificity, positive and negative predictive values. The need for treatment, observation, or serial testing with respect to risks and benefits of treatment and likelihood of serious outcomes was evaluated. The evidence for conclusions was based on the methodology and values of the Canadian Task Force on the Periodic Health Examination. The Diagnostic Imaging Advisory Group of the Canadian Association of Emergency Physicians developed eight recommendations.

Copper-binding compounds from Methylosinus trichosporium OB3b

Two copper-binding compounds/cofactors (CBCs) were isolated from the spent media of both the wild type and a constitutive soluble methane monooxygenase (sMMOC) mutant, PP319 (P. A. Phelps et al., Appl. Environ. Microbiol. 58:3701-3708, 1992), of Methylosinus trichosporium OB3b. Both CBCs are small polypeptides with molecular masses of 1,218 and 779 Da for CBC-L1 and CBC-L2, respectively. The amino acid sequence of CBC-L1 is S?MYPGS?M, and that of CBC-L2 is SPMP?S. Copper-free CBCs showed absorption maxima at 204, 275, 333, and 356 with shoulders at 222 and 400 nm. Copper-containing CBCs showed a broad absorption maximum at 245 nm. The low-temperature electron paramagnetic resonance (EPR) spectra of copper-containing CBC-L1 showed the presence of a copper center with an EPR splitting constant between those of type 1 and type 2 copper centers (g = 2.087, g = 2.42 G, A = 128 G). The EPR spectrum of CBC-L2 was more complex and showed two spectrally distinct copper centers. One signal can be attributed to a type 2 Cu2+ center (g = 2.073, g = 2.324 G, A = 144 G) which could be saturated at higher powers, while the second shows a broad, nearly isotropic signal near g = 2.063. In wild-type strains, the concentrations of CBCs in the spent media were highest in cells expressing the pMMO and stressed for copper. In contrast to wild-type strains, high concentrations of CBCs were observed in the extracellular fraction of the sMMOC mutants PP319 and PP359 regardless of the copper concentration in the culture medium.