Single-step separation of platelets from whole blood coupled with digital quantification by interfacial platelet cytometry (iPC)

We report the efficient single-step separation of individual platelets from unprocessed whole blood, enabling digital quantification of platelet function using interfacial platelet cytometry (iPC) on a chip. iPC is accomplished by the precision micropatterning of platelet-specific protein surfaces on solid substrates. By separating platelets from whole blood using specific binding to protein spots of a defined size, iPC implements a simple incubate-and-rinse approach, without sample preparation, that enables (1) the study of platelets in the physiological situation of interaction with a protein surface, (2) the choice of the number of platelets bound on each protein spot, from one to many, (3) control of the platelet-platelet distance, including the possibility to study noninteracting single platelets, (4) digital quantification (counting) of platelet adhesion to selected protein matrices, enabling statistical characterization of platelet subpopulations from meaningfully large numbers of single platelets, (5) the study of platelet receptor expression and spatial distribution, and (6) a detailed study of the morphology of isolated single platelets at activation levels that can be manipulated. To date, we have demonstrated 1-4 of the above list. Platelets were separated from whole blood using iPC with fibrinogen, von Willebrand factor (VWF), and anti-CD42b antibody printed "spots" ranging from a fraction of one to several platelet diameters (2-24 μm). The number of platelets captured per spot depends strongly on the protein matrix and the surface area of the spot, together with the platelet volume, morphology, and activation state. Blood samples from healthy donors, a May-Hegglin-anomaly patient, and a Glanzmann's Thrombasthenia patient were analyzed via iPC to confirm the specificity of the interaction between protein matrices and platelets. For example, the results indicate that platelets interact with fibrinogen spots only through the fibrinogen receptor (αIIbβ3) and, relevant to diagnostic applications, platelet adhesion correlates strongly with normal versus abnormal platelet function. A critical function of platelets is to adhere to regions of damage on blood vessel walls; in contrast to conventional flow cytometry, where platelets are suspended in solution, iPC enables physiologically relevant platelet bioassays based on platelet/protein-matrix interactions on surfaces. This technology should be inexpensive to implement in clinical assay format, is readily integrable into fluidic microdevices, and paves the way for high-throughput platelet assays from microliter volumes of whole blood.

Postmenopausal hormone therapy and cognition: effects of timing and treatment type

SETTING

Hormone therapy used for the management of postmenopausal symptoms in older women appears to result in variable effects on cognitive function, depending on study design, subjects, tests used, and types of therapy.

OBJECTIVE

To determine the effects of estrogen-only and estrogen plus progestogen preparations on cognitive performance (cognitive status, general and working memory) when taken 'early' and 'late' from the onset of menopause.

METHOD

The study consisted of 410 women who were participants in a longitudinal study, first recruited at age 40-80 years. They were tested for change over 5 years as an observational cohort by the Mini-Mental State Examination, National Adult Reading Test and the Wechsler Memory Scale Version 3. Cognitive decline, measured by age-adjusted scores, was defined as >or=10% negative change in each individual woman.

RESULTS

Controlling for age and lifestyle factors, and using the criterion of decrease in score >or=10% over 5 years for 'cognitive decline', 'early start' of hormone therapy (<3 years from menopause) was strongly associated with reduction in risk by the Mini-Mental State Examination (estrogen-only preparation, p = 0.005) but with increase in risk for general memory (with estrogen plus progestogen preparation, p = 0.02). Overall, there were no major effects on subgroups with type/timing of hormone therapy in relation to testing for a negative change in cognitive function.

CONCLUSION

'Early start' of estrogen-only hormone therapy was associated with reduced risk of global cognitive decline, and 'early start' estrogen-only and estrogen/progestogen hormone therapies showed increased risks of general memory decline. Even though this study did not have the power to discriminate between minor and mixed effects, it suggests that cognitive effects of hormone therapies may be mixed, depending on cognitive domain and timing of use/type of preparation.

Cyclical vomiting syndrome: diagnosis, causes and treatment

Cyclical vomiting syndrome (CVS) is a disorder of unknown cause. Patients experience episodes of sudden violent vomiting that last from a few hours to a few days, which can occur several times a year. CVS affects children and adults yet despite numerous studies the cause of the condition is unknown. The aim of this article is to outline the current theories for the possible causes of CVS and to examine the various treatment options available.

Endometrial and vaginal effects of low-dose estradiol delivered by vaginal ring or vaginal tablet

AIMS

The major aims of the study were to compare the safety of a continuous low-dose estradiol-releasing vaginal ring (ESTring) to that of a vaginal estradiol tablet (Vagifem) on the endometrium and the relief of subjective symptoms and signs of urogenital estrogen deficiency. Quality of life and acceptability of treatment delivery were also assessed.

STUDY DESIGN

A prospective, randomized study in which women were assigned in a 2:1 ratio to ESTring and Vagifem and followed for 12 months. The primary endpoint was endometrial safety, based on the results of ultrasound measurement of endometrial thickness and a progestogen challenge test at baseline and week 48. Efficacy was determined by subjective assessment of urogenital estrogen deficiency symptoms at baseline and weeks 3, 12, 24, 36 and 48 and assessment of signs of vaginal epithelial atrophy by the clinician at baseline, 12 and 48 weeks. In addition, pelvic floor strength, vaginal cytological evaluation and pH, bacteruria and patient acceptability were assessed. Quality of life was assessed using a menopause-specific quality-of-life questionnaire and a 2-day bladder diary at baseline and 12 and 48 weeks. The comparability of the two groups was assessed using ANOVA, chi2 or Fisher's exact tests.

RESULTS

A total of 126 women were randomized to ESTring and 59 to Vagifem. There was no statistical difference between the groups in the alleviation of symptoms and signs of urogenital estrogen deficiency. Maturation indices increased in both groups, from generally atrophic at baseline to proliferative or highly proliferative at 48 weeks. After 48 weeks of treatment, there was no statistically significant difference in endometrial thickness between the two groups. A statistically smaller proportion of bleeding/spotting occurred in the ESTring group (n = 0) compared to the Vagifem users (n = 4). Estradiol and total estrone serum levels increased during treatment in both groups but remained within the normal postmenopausal range. General health status in both groups was unchanged but the urogenital component of health burden was significantly improved in both groups. Bladder diary variables showed no differences between treatment groups.

CONCLUSION

Equivalent endometrial safety and efficacy in the relief of the symptoms and signs of urogenital estrogen deficiency were demonstrated for the 12 months' use of a low-dose estradiol-releasing vaginal ring and a vaginal estradiol tablet.

Ca(2+)-calmodulin can activate and inactivate cardiac ryanodine receptors

BACKGROUND AND PURPOSE

Ca(2+)-calmodulin (Ca(2+)CaM) is widely accepted as an inhibitor of cardiac ryanodine receptors (RyR2); however, the effects of physiologically relevant CaM concentrations have not been fully investigated.

EXPERIMENTAL APPROACH

We investigated the effects of low concentrations of Ca(2+)CaM (50-100 nmol.L(-1)) on the gating of native sheep RyR2, reconstituted into bilayers. Suramin displaces CaM from RyR2 and we have used a gel-shift assay to provide evidence of the mechanism underlying this effect. Finally, using suramin to displace endogenous CaM from RyR2 in permeabilized cardiac cells, we have investigated the effects of 50 nmol.L(-1) CaM on sarcoplasmic reticulum (SR) Ca(2+)-release.

KEY RESULTS

Ca(2+)CaM activated or inhibited single RyR2, but activation was much more likely at low (50-100 nmol.L(-1)) concentrations. Also, suramin displaced CaM from a peptide of the CaM binding domain of RyR2, indicating that, like the skeletal isoform (RyR1), suramin directly competes with CaM for its binding site on the channel. Pre-treatment of rat permeabilized ventricular myocytes with suramin to displace CaM, followed by addition of 50 nmol x L(-1) CaM to the mock cytoplasmic solution caused an increase in the frequency of spontaneous Ca(2+)-release events. Application of caffeine demonstrated that 50 nmol x L(-1) CaM reduced SR Ca(2+) content.

CONCLUSIONS AND IMPLICATIONS

We describe for the first time how Ca(2+)CaM is capable, not only of inactivating, but also of activating RyR2 channels in bilayers in a CaM kinase II-independent manner. Similarly, in cardiac cells, CaM stimulates SR Ca(2+)-release and the use of caffeine suggests that this is a RyR2-mediated effect.

Reactivity to autologous serum skin test and relationship with complement levels in chronic idiopathic urticaria and angio-oedema

BACKGROUND

A role for complement in autoantibody-mediated histamine release in urticaria has been suggested but not proven in vivo. Aim. To study serum complement levels in patients with chronic idiopathic urticaria (CIU) and to determine whether there was a relationship with autologous serum skin test (ASST) reactivity.

METHODS

We recruited 35 patients with CIU. Complement (C3, C4) levels and ASST were measured in all patients; additional investigations were undertaken dependent on history and examination.

RESULTS

Complement concentrations were outside the population reference intervals in 19/35 patients, with low C3 noted in 3/35 and low C4 in 18/35. Of 12 patients with a positive ASST, 7 had low complement levels, and 12/23 with a negative ASST had low complement levels. Patients with a positive ASST had a median C3 of 1.24 g/L (range 0.35-1.51) compared with a median of 1.25 g/L in those with a negative ASST (P = 0.36), and a median C4 of 0.20 g/L (range 0.185-0.452) in those with a positive ASST compared with 0.18 g/L in those with a negative ASST (P = 0.88).

CONCLUSIONS

We conclude that both a reduction in C4 and positive ASST are common in CIU and although these immunological abnormalities often coexist, there is no clear relationship between them. Other components of the complement system may be worth exploring.

Positive effects of exercise on falls and fracture risk in osteopenic women

Exercise may affect osteopenic women at risk of falls and fractures. A workstation approach to exercise was evaluated in a randomised study of 98 women. The intervention group improved in measures of balance, strength and bone density. This study supports a preventative exercise approach that aims to reduce risk factors for fractures and falls, in women already at risk, through balance training and weight-bearing activity.

INTRODUCTION

The objective of this study was to determine the effects of a workstation balance training and weight-bearing exercise program on balance, strength and bone mineral density (BMD) in osteopenic women. A single-blinded randomised controlled trial (RCT) was undertaken for 20 weeks with measurements at baseline and completion.

MATERIALS AND METHODS

Ninety-eight (98) community-dwelling osteopenic women aged 41-78 years were recruited through the North Brisbane electoral roll. Subjects were randomised via computer-generated random numbers lists into either a control (receiving no intervention), or exercise group (two one-hour exercise sessions per week for 20 weeks with a trained physiotherapist). Assessments at baseline and post-intervention included balance testing (five measures), strength testing (quadriceps, hip adductors / abductors / external rotators and trunk extensors), and DXA scans (proximal femur and lumbar spine). Baseline assessment showed no significant differences between groups for all demographics and measures except for subjects taking osteoporosis medication. The percentage differences between pre- and post-intervention measurements were examined for group effect by ANOVA using an intention-to-treat protocol.

RESULTS

Ninety-eight women (mean age 62.01 years, SD 8.9 years) enrolled in the study. The mean number of classes attended for the 42 participants in the exercise group who completed the program was 28.2 of a possible 40 classes (71%). At the completion of the trial the intervention group showed markedly significant better performances in balance (unilateral and bilateral stance sway measures, lateral reach, timed up and go and step test) (p < 0.05) with strong positive training effects reflecting improvements of between 10% to 71%. Similarly there were gains in strength of the hip muscles (abductors, adductors, and external rotators), quadriceps and trunk extensors with training effects between 9% and 23%.

CONCLUSIONS

Specific workstation exercises can significantly improve balance and strength in osteopenic women. This type of training may also positively influence bone density although further study is required with intervention over a longer period. A preventative exercise program may reduce the risk of falls and fractures in osteopenic women already at risk.

The older persons' assessment and liaison team 'OPAL': evaluation of comprehensive geriatric assessment in acute medical inpatients

BACKGROUND

Reducing hospital length of stay (LOS) in older acute medical inpatients is a key productivity measure. Evidence-based predictors of greater LOS may be targeted through Comprehensive Geriatric Assessment (CGA).

OBJECTIVE

Evaluate a novel service model for CGA screening of older acute medical inpatients linked to geriatric intervention.

SETTING

Urban teaching hospital.

SUBJECTS

Acute medical inpatients aged 70+ years.

INTERVENTION

Multidisciplinary CGA screening of all acute medical admissions aged 70+ years leading to (a) rapid transfer to geriatric wards or (b) case-management on general medical wards by Older Persons Assessment and Liaison team (OPAL).

METHODS

Prospective pre-post comparison with statistical adjustment for baseline factors, and use of national benchmarking LOS data. Pre-OPAL (n = 46) and post-OPAL (n = 49) cohorts were similarly identified as high-risk by the CGA screening tool, but only post-OPAL patients received the intervention.

RESULTS

Pre-OPAL, 0% fallers versus 92% post-OPAL were specifically assessed and/or referred to a falls service post-discharge. Management of delirium, chronic pain, constipation, and urinary incontinence similarly improved. Over twice as many patients were transferred to geriatric wards, with mean days from admission to transfer falling from 10 to 3. Mean LOS fell by 4 days post-OPAL. Only the OPAL intervention was associated with LOS (P = 0.023) in multiple linear regression including case-mix variables (e.g. age, function, 'geriatric giants'). Benchmarking data showed the LOS reduction to be greater than comparable hospitals.

CONCLUSION

CGA screening of acute medical inpatients leading to early geriatric intervention (ward-based case management, appropriate transfer to geriatric wards), improved clinical effectiveness and general hospital performance.

Factors affecting sexuality in older Australian women: sexual interest, sexual arousal, relationships and sexual distress in older Australian women

OBJECTIVE

To investigate the sexual behavior, sexual relationships, sexual satisfaction, sexual dysfunction and sexual distress in a population of older urban Australian women.

METHOD

In 2004, 474 women participating in the Longitudinal Assessment of Ageing in Women (LAW) Study completed a series of questionnaires about sexuality. They included the Short Personal Experiences Questionnaire (SPEQ), Relationship Assessment Scale (RAS), Female Sexual Distress Scale (FSDS), questions concerning past sexual abuse based on the Sex in Australia Study, and questions comparing present and past sexual interest and activity.

RESULTS

The percentage of women with partners ranged from 83.3% in the 40 - 49-year age group to 46.4% women in the 70 - 79-year age group. The sexual ability of partners diminished markedly with age, with only 4.8% of the partners using medication to enable erections. Only 2.5% of women reported low relationship satisfaction. The incidence of sexual distress was also low, being reported by only 5.7% of women. Younger women and women with partners had higher levels of distress than older women. Indifference to sexual frequency rose from 26.7% in women aged 40 - 49 years to 72.3% in the 70 - 79-year age group. Past sexual abuse was recalled by 22.7% of women and 11.6% recalled multiple episodes of abuse. Women who recalled abuse had lower scores for satisfaction with sexual frequency.

CONCLUSIONS

It appears from this study that there is a wide range of sexual experience amongst aging women, from never having had a sexual partner, to having solitary sex, to having a relationship with or without sex into the seventh decade. As women age, they experience a decrease in sexual activity, interest in sex, and distress about sex. This may be associated with the loss of intimate relationships as part of separation, divorce or bereavement. Decreased sexual activity with aging may be interpreted as a biological phenomenon (part of the aging process) or as sexual dysfunction, or it may be the result of adapting to changed circumstances.

[Semantic dementia, a many-worded disorder]

INTRODUCTION

Semantic dementia is a progressive, relatively selective disorder affecting the semantic system with involvement of the verbal and non-verbal functions. The clinical picture is well characterised despite the confusion that may be generated by the different ways of classifying it. AIM. To determine the clinical, neurolinguistic, imaging and pathological features of this progressive language disorder.

DEVELOPMENT

Evaluation of language reveals above all the existence of semantic paraphasias, disorders affecting the comprehension of isolated words and surface dyslexia. Flow of speech, complex syntactic comprehension and grammar are preserved. Both episodic and autobiographic memory are close to normality. Both the clinical signs and symptoms and imaging studies agree on the fact that the most heavily affected area is the anteroinferomedial region of the temporal lobe on a bilateral scale but with predominance of the left-hand side. Pathologically, in most cases positive intraneuronal ubiquitin inclusions are observed like those described in motor neuron diseases.

CONCLUSIONS

Semantic dementia constitutes a diagnosis challenge, mainly from the neuropsychological point of view. Further advances towards reaching a diagnosis would allow us to determine which area is mainly affected and, in the future, to find an effective treatment for this progressive, degenerative disorder.

A Prospective Analysis of Fenestrated Endovascular Grafting: Intermediate-term Outcomes

PURPOSE

To assess the intermediate-term outcomes following fenestrated grafting for juxtarenal aneurysms.

MATERIALS AND METHODS

A prospective trial was conducted on patients with short proximal necks, who were considered to be high-risk for open repair and unacceptable for conventional endovascular repair. Devices were designed from reconstructed CT data. Follow-up studies included CT, duplex ultrasound, and KUB and occurred at hospital discharge, 1, 6, and 12 months and annually thereafter.

RESULTS

One hundred and nineteen patients were treated (2001-2005). Mean age and aneurysm size were 75 years and 65 mm, respectively, and 82% were male. A total of 302 visceral vessels were inferior to the fabric seal (a mean of 2.5 vessels per patient), with the most common design incorporating two renal arteries and the SMA (58%). All prostheses were implanted successfully without any acute visceral artery loss. The mean follow-up was 19 months (0-42 months). One patient died within 30 days of device implantation. Kaplan-Meier estimates of survival at 1, 12, 24, and 36 months are 0.99, 0.92, 0.83 and 0.79. There were no ruptures or conversions. Pre-discharge imaging noted 11 type I and type III endoleaks. The 30-day endoleak rate was 10% (all type II). Aneurysm sac size decreased (>5 mm) in 51, 79 and 77% at 6, 12 and 24 months, respectively. One patient had sac enlargement within the first year, associated with a persistent type II endoleak. In-stent stenoses occurred in 12 renal arteries and one SMA. Six renal arteries and the SMA stenosis were treated and two renal stenoses are awaiting treatment. Ten of 231 stented renal arteries occluded (three prior to discharge), one of which was recanalized. One component separation was treated with an extension at 2 years.

CONCLUSIONS

The placement of endovascular prostheses with graft material incorporating the visceral arteries is safe and appears to be effective at preventing rupture. Continued follow-up to assess the long-term benefit, aneurysm sac behavior and effect of stenting upon the visceral ostia remains critical.

A case of multiple cerebral abscesses due to infection with Cladophialophora bantiana

Cladophialophora bantiana is a highly neurotropic fungus which has been reported to cause a variety of infections in the immunocompromised and transplant populations. We describe a case of multiple cerebral abscesses caused by this dematiaceous fungus in a patient with probable Duncan's syndrome. The patient also had extensive extra-cerebral disease, which is unusual for infection with this organism. We discuss previously described cases of infection with Cladophialophora bantiana, and review the current and evolving treatment options.