Effects of a gamma-secretase inhibitor in a randomized study of patients with Alzheimer disease

LY450139 dihydrate, a gamma-secretase inhibitor, was studied in a randomized, controlled trial of 70 patients with Alzheimer disease. Subjects were given 30 mg for 1 week followed by 40 mg for 5 weeks. Treatment was well tolerated. Abeta(1-40) in plasma decreased by 38.2%; in CSF, Abeta(1-40) decreased by 4.42 +/- 9.55% (p = not significant). Higher drug doses may result in additional decreases in plasma Abeta concentrations and a measurable decrease in CSF Abeta.

Brain volume loss in MCI predicts dementia

Rates of temporal horn volume change were significantly greater in the subjects with mild cognitive impairment who were developing dementia vs those who remained stable.

Symptomatic hypocalcaemia and renal impairment associated with bisphosphonate treatment in patients with multiple myeloma

We report three cases of severe hypocalcaemia associated with i.v. bisphosphonate treatment in patients with multiple myeloma. All patients had symptomatic hypocalcaemia, including a tonic-clonic seizure and tachyarrhythmia in one case. Two cases were associated with the development of acute renal failure, whereas the third patient had pre-existing renal impairment. We recommend that bisphosphonates be used with caution in patients with myeloma and renal impairment, that vitamin D deficiency be corrected prior to treatment (to reduce the risk of hypocalcaemia) and that serum calcium and renal function be monitored during treatment.

Lessons from European population genetic databases: comparing the law in Estonia, Iceland, Sweden and the United Kingdom

The advent of large-scale, population genetic databases (PGDs) in several countries around the world marks a significant development in human DNA banking and genetic research. The European countries that have led the way in the development of PGDs are Iceland, Sweden, Estonia and the U.K. In legal terms, the emergence of PGDs has been far from straightforward as such projects pose a range of difficult and complex issues for the law to address. This article canvasses the current law in Iceland, Estonia, Sweden and the U.K. on four fundamental issues of principle pertaining to PGDs, in order to illustrate the difficulties that have emerged around PGDs, highlight key areas of legal concern, and shed light on possible ways forward. It compares and contrasts the differing legal positions and lawmakers' responses to date in these four European countries that have established PGDs or are seeking to do so. The four fundamental issues examined are: (1) consent, especially for secondary research purposes; (2) ownership of biological samples, data and databases; (3) the rights of certain third parties to gain access to, and to use, PGD biological samples and data; and (4) benefit sharing, including the provision of feedback and genetic counselling to participants. This analysis may offer some guidance for policymakers in other jurisdictions where PGDs have been proposed or are being established.

Governing UK Biobank: the importance of ensuring public trust

In the autumn of 2003, UK Biobank published the first draft of its Ethics and Governance Framework. Subsequently, this document has been available for interested parties to comment on and the UK Biobank Board of Directors is expected to adopt the final version in 2004. Here, we aim to contribute to this process and highlight to a wider audience some of the inconsistencies in the issues of consent, governance and right of withdrawal that emerge from the draft of the Framework. These issues will have implications for securing the public trust and long-term support that the success of the project depends on. Therefore, they must be considered carefully because the UK Biobank will be the first ever genetic database of a general population of this size to become operational, and will be used as a model for other projects of this kind.

Acute carbon dioxide exposure in healthy adults: evaluation of a novel means of investigating the stress response

Acute hypercapnia was studied to assess its potential as a noninvasive and simple test for evoking neuroendocrine, cardiovascular and psychological responses to stress in man. A single breath of four concentrations of carbon dioxide (CO(2)), 5%, 25%, 35% and 50%, was administered to nine healthy volunteers in a randomized, single-blind fashion. Although no adverse effects occurred, most subjects were unable to take a full inspired vital capacity breath of 50% CO(2). In response to the remaining exposures, subjective and somatic symptoms of anxiety increased in a dose-dependent manner. Unlike 5% and 25% CO(2), 35% CO(2) stimulated significant adrenocorticotropic hormone and noradrenaline release at 2 min and cortisol and prolactin release at 15 min following inhalation. This same dose also provoked a significant bradycardia that was followed by an acute pressor response. No significant habituation of psychological, hypothalamic-pituitary-adrenal (HPA) or cardiovascular responses following 35% CO(2) was seen when this dose was repeated after 1 week. A single breath of 35% CO(2) safely and reliably produced sympathetic and HPA axis activation and should prove a useful addition to currently available laboratory tests of the human stress response.

Metastases to the breast revisited: radiological-histopathological correlation

Metastases to the breast from extramammary tumours are infrequent. The main challenge in diagnosis is differentiating them from primary breast cancer. Radiologically this can be difficult as there are no specific imaging characteristics for metastases to the breast. Cytopathological evaluation, as well as full radiological assessment, is vital to avoid unnecessary surgery. Sources of primary tumours include a wide variety of cancers. In this pictorial review we illustrate a number of the commonest sources of primary tumours including lymphoma, lung, ovarian and cervical carcinoma, intestinal carcinoid and rare cases of Ewing's sarcoma and malignant pigmented melanocytic schwannoma (low-grade malignant melanoma).

Multidisciplinary rehabilitation for people with Parkinson's disease: a randomised controlled study

OBJECTIVE

To determine whether a programme of multidisciplinary rehabilitation and group support achieves sustained benefit for people with Parkinson's disease or their carers.

METHODS

The study was a randomised controlled crossover trial comparing patients and carers who had received rehabilitation four months before assessment with those who had not. Patients were recruited from a neurology clinic, attended a day hospital from home weekly for six weeks using private car or hospital transport, and received group educational activities and individual rehabilitation from a multidisciplinary team. Patients were assessed at entry and at six months using a 25 item self assessment Parkinson's disease disability questionnaire, Euroqol-5d, SF-36, PDQ-39, hospital anxiety and depression scale, and timed stand-walk-sit test. Carers were assessed using the carer strain index and Euroqol-5d.

RESULTS

144 people with Parkinson's disease without severe cognitive losses and able to travel to hospital were registered (seven were duplicate registrations); 94 had assessments at baseline and six months. Repeated measures analysis of variance comparing patients at the 24 week crossover point showed that those receiving rehabilitation had a trend towards better stand-walk-sit score (p = 0.093) and worse general and mental health (p = 0.002, p = 0.019). Carers of treated patients had a trend towards more strain (p = 0.086). Analysis comparing patients before and six months after treatment showed worsening in disability, quality of life, and carer strain.

CONCLUSIONS

Patients with Parkinson's disease decline significantly over six months, but a short spell of multidisciplinary rehabilitation may improve mobility. Follow up treatments may be needed to maintain any benefit.

Redesigning geriatric healthcare: how cross-functional teams and process improvement provide a competitive advantage

This study examines the consequences of adding a geriatric subacute unit to the traditional health care mix offered by a nonprofit hospital. Historically, geriatric health care offerings have been limited to either acute care units or long-term care facilities. The study's findings demonstrate that the addition of a subacute unit that is operated by an interdisciplinary team is a competitively rational move for two reasons. First, it provides a continuum of care that integrates services and departments, thereby reducing costs. Second, it provides a supportive environment for patients and their families. As a consequence patients have a higher probability of returning home than patients who are assigned to more traditional modes of care.

Soft tissue uptake on 99mTc methylene diphosphonate bone scan imaging: pictorial review

99mTechnetium methylene diphosphonate (MDP) bone isotope may accumulate in many extra-osseous sites due to a variety of both benign and malignant conditions. This finding on a bone scan can be crucial to the diagnosis and may not be apparent in other imaging or the clinical evaluation of the patient. We present a pictorial review sampling some of the many causes of extra-osseous 99mTc MDP accumulation.

Genetic research on the UK population--do new principles need to be developed?

Governments around the world are beginning to generate population databases as resources for genetic research. In the UK, a proposal has been tabled that plans to incorporate National Health Service information--a move that will effectively create a database of around 60 million. However, this new population collection will not conform to standards established by other national genetic databases, and the UK government report has not accounted for key ethical issues.

Requirement for sustained MAPK signaling in both CD4 and CD8 lineage commitment: a threshold model

Although there is general agreement that the RAS/MAPK signaling pathway is required for positive selection of CD4 T cells in the thymus, the role of this pathway in CD8 lineage commitment remains controversial. We show here that the differentiation of isolated cultured thymocytes to the CD8 as well as CD4 T cell lineage is sensitive to MEK inhibition and that both CD4 and CD8 thymocyte differentiation requires sustained MEK signaling. However, CD4 lineage commitment is promoted by a stronger stimulus for longer duration than required for CD8 lineage commitment. Interestingly, CD4 lineage commitment is not irreversibly set even after 10 h of signaling, well past early changes in gene expression. These findings are presented in the context of a model of lineage commitment in which a default pathway of CD8 lineage commitment is altered to CD4 commitment if the thymocyte achieves a threshold level of active MAPK within a certain time frame.

Pheochromocytoma presenting as life-threatening pulmonary edema

Acute cardiogenic pulmonary edema as the first presentation of pheochromocytoma is uncommon and usually rapidly fatal. A 39-yr-old man presented in acute cardiogenic shock with global ventricular dysfunction that required high-dose iv inotrope support and an intraaortic balloon pump assist device. Abdominal imaging to exclude aortic dissection revealed a 6-cm right adrenal mass. Significant myocardial infarction (electrocardiographic changes and elevated cardiac enzymes) contributed to the cardiac decompensation. After withdrawal of inotrope support, 24-h urinary catecholamine levels revealed 2,155 nmol/d (<125) of adrenaline and 7,437 nmol/d (<560) of noradrenaline, confirming a pheochromocytoma. The tumor was successfully removed at laparotomy; however, the patient's course was complicated by a thromboembolic cerebrovascular accident with paraplegia. He recovered cardiac function almost completely within 3 wk of medical therapy alone. Although uncommon, this case highlights the need to consider pheochromocytoma early in the management of unexplained cardiogenic shock.

Predictors of healthy brain aging

To determine if superior health at old age protects against cognitive impairment (CI) and Alzheimer's disease (AD), we prospectively studied 100 optimally healthy oldest-old (> or =85 years) individuals. Initially, subjects represented the top 3% of the oldest old for health. During 5.6 +/- 0.3 years of follow-up, 34 subjects developed CI, and 23 progressed to AD. By age 100, probability of CI and AD were.65 +/-.09 and.49 +/-.10. Median onset age was 97 years for CI and 100 for AD. Clearly, superior health at old age does not guarantee protection against cognitive decline. Lifetime risks were similar to the general population but onset ages were later, suggesting factors that delay onset are key to improving cognitive health in the elderly. In this population, absence of apolipoprotein E-epsilon4 and male gender were associated with delayed onset, whereas estrogen use and education had no detectable effect on cognitive outcome.

Parkinson's disease, CYP2D6 polymorphism, and age

OBJECTIVE

PD may be caused by genetic susceptibility to neurotoxins. CYP2D6 is a candidate gene for PD because it regulates drug and toxin metabolism, but association studies have been inconsistent. The aim of this study was to test if the CYP2D6*4 allele (poor metabolizer phenotype) is associated with earlier age at onset.

METHODS

Five hundred seventy-six patients with PD and 247 subjects without PD were studied using standard diagnostic, genotyping, and statistical techniques.

RESULTS

Surprisingly, mean onset age was significantly later in *4-positive patients. Frequency of *4 was significantly higher in late-onset PD than early-onset PD. When early- and late-onset PD were analyzed separately, *4 had no effect on onset age; hence, the association with delayed onset was likely an artifact of an elevated *4 frequency in late-onset PD. Contrary to a common assumption that CYP2D6 frequencies do not change with age, *4 frequency rose significantly with advancing age, both in patients with PD (from 0.16 at mean age of 56.5 years to 0.21 at mean age of 72) and subjects without PD (from 0.09 at mean age of 45.5 years to 0.21 at mean age of 72). *4 Frequencies in patients with early- and late-onset PD, although different from each other, were in agreement with similarly aged subjects without PD, suggesting the elevated *4 frequency in late-onset PD was likely an age effect, unrelated to PD.

CONCLUSION

The CYP2D6*4 allele is not associated with earlier PD onset. *4 May be associated with survival. Inconsistent results from allelic association studies may have been due to an unrecognized age effect.

Paradoxical embolism: computed tomography demonstration

Paradoxical emboli are rare and often presumptively diagnosed. A case of paradoxical embolism, in which both the arterial and venous emboli were documented on CT, is described.

Anatomical and physiological simulation for respiratory mechanics

Injuries in trauma affect anatomical structures, indirectly affecting physiological systems through mechanical behavior and physical proximity. This paper describes the theory for and preliminary results from our approach to couple a three-dimensional (3-D) anatomical model of the chest with a physiological model of respiratory mechanics. In particular, we investigated behavior in quiet, normal breathing and in an open, sucking chest wound. We envision that our integrated simulation of respiratory anatomy and respiratory mechanics could assist students in visualizing and predicting relationships between structural-anatomical and functional-physiological changes in an interactive, 3-D environment.

Longitudinal analysis of the effects of the aging process on neuropsychological test performance in the healthy young-old and oldest-old

A sample of 33 young-old (ages 65 to 74) and 20 oldest-old (ages 84 to 93) healthy elderly without dementia were assessed with neuropsychological tests annually over a 4-year period to examine longitudinal changes in cognitive functioning. Significant age-group differences existed at baseline in participants' performances on tests of immediate memory and visuospatial skills. There were no age-group differences in the rate of change over the 4-year interval on any neuropsychological tests. Within each age-group, the amount of change over time was minimal for most tests though some practice effects were apparent, and on some tests mild decline was observed. Results suggest that healthy old adults, including the oldest-old, do not experience measurable declines in cognitive functioning over a 4-year period.

Patency of radial arterial catheters

BACKGROUND

Data on the influence of flush methods, blood-sampling methods, and site location on the patency of radial arterial catheters used for pressure monitoring are sparse.

OBJECTIVES

To determine the effects of flush and blood-sampling methods, insertion site, and sex of patients on catheter patency.

METHODS

In a randomized trial, 174 patients requiring radial arterial pressure monitoring were assigned to 4 groups: fast flush as needed and nonwaste blood sampling; fast flush as needed and waste blood sampling; fast flush every 4 hours and waste blood sampling; and fast flush every 4 hours and nonwaste blood sampling. All site locations were evaluated for patency, and all monitoring systems were maintained with isotonic sodium chloride solution.

RESULTS

Nonpatent catheters were 4.23 times more likely in patients with insertion sites 3 cm or higher above the bend of the wrist than in patients with lower sites (P = .01). Duration of patency did not differ between catheters maintained with fast flush every 4 hours and those flushed as needed or between catheters according to the method of blood sampling. Women were 3.05 times more likely than men to have nonpatent catheters (P = .02). With insertion sites 3 cm or higher above the radiocarpal joint, nonpatency was 7.3 times more likely in women than in men (P < .001).

CONCLUSIONS

Insertion sites closest to the bend of the wrist increase chances of maintaining patency. Catheters can be maintained with as-needed flushes, and either waste or nonwaste blood sampling can be used.

Patency of radial arterial catheters

BACKGROUND: Data on the influence of flush methods, blood-sampling methods, and site location on the patency of radial arterial catheters used for pressure monitoring are sparse. OBJECTIVES: To determine the effects of flush and blood-sampling methods, insertion site, and sex of patients on catheter patency. METHODS: In a randomized trial, 174 patients requiring radial arterial pressure monitoring were assigned to 4 groups: fast flush as needed and nonwaste blood sampling; fast flush as needed and waste blood sampling; fast flush every 4 hours and waste blood sampling; and fast flush every 4 hours and nonwaste blood sampling. All site locations were evaluated for patency, and all monitoring systems were maintained with isotonic sodium chloride solution. RESULTS: Nonpatent catheters were 4.23 times more likely in patients with insertion sites 3 cm or higher above the bend of the wrist than in patients with lower sites (P = .01). Duration of patency did not differ between catheters maintained with fast flush every 4 hours and those flushed as needed or between catheters according to the method of blood sampling. Women were 3.05 times more likely than men to have nonpatent catheters (P = .02). With insertion sites 3 cm or higher above the radiocarpal joint, nonpatency was 7.3 times more likely in women than in men (P &lt; .001). CONCLUSIONS: Insertion sites closest to the bend of the wrist increase chances of maintaining patency. Catheters can be maintained with as-needed flushes, and either waste or nonwaste blood sampling can be used.

Dementia in rural primary care practices in Lake County, Oregon

Procedures used in assessing patients with dementia in rural settings are little studied. Among all patients aged 65 years and older in the four primary care practices in Lake County, Oregon, dementia cases were identified from computerized office databases using preselected International Classification of Diseases, Ninth Edition, codes. A semi-structured chart review determined (1) a dementia diagnosis, (2) cognitive and functional domains assessed, and (3) diagnostic studies performed. Of 1540 available records, 30 had dementia. Nineteen of them met National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD). Cognitive impairment was documented in 73% of the 51 identified charts and all with AD. Laboratory studies were recorded in 33% overall and in 42% with AD. Neuroimaging was documented in 18% overall and in 16% with AD. The prevalence of documented dementia in these rural practices may be low, possibly because cases of mild dementia may not be labeled as such. Laboratory studies were performed in a minority of cases of dementia.

Moderating and mediating effects in causal models

This article explains causal relationships in conceptual models of mental health phenomena. Direct, moderating, mediating, and reciprocal effects among variables are defined, appropriate statistical analyses are described, and the correct interpretations of moderating versus mediating effects are discussed. Examples are provided that will help the reader to distinguish between moderating and mediating effects.