All-optical binary counter

We experimentally demonstrate an all-optical binary counter composed of four semiconductor optical amplifier based all-optical switching gates. The time-of-flight optical circuit operates with bit-differential delays between the exclusive-OR gate used for modulo-2 binary addition and the AND gate used for binary carry detection. A movie of the counter operating in real time is presented.

Multicentre evaluation of the Boehringer Mannheim/Hitachi 917 analysis system

The new selective access analysis system BM/Hitachi 917 was evaluated in an international multicentre study, mainly according to the ECCLS protocol for the evaluation of analysers in clinical chemistry. Forty-three different analytes, covering 56 different methods--enzymes, substrates, electrolytes, specific proteins, drugs and urine applications--were tested in seven European clinical chemistry laboratories. Additionally, the practicability of the BM/ Hitachi 917 was tested according to a standardized questionnaire. Within-run CVs (median of 3 days) for enzymes, substrates and electrolytes were <2% except for creatine-kinase MB isoform and lipase at low concentration. For proteins, drugs and urine analytes the within-run CVs were < 4% except for digoxin and albumin in urine. Between-day median CVs were generally < 3% for enzymes, substrates and electrolytes, and < 6% for proteins, drugs and urine analytes, except for lipase, creatine kinase and MB isoform, D-dimer, glycosylated haemoglobin, rheumatoid factors, digoxin, digitoxin, theophylline and albumin in urine in some materials. Linearity was found according to the test specifications or better and there were no relevant effects seen in drift and carry-over testing. The interference results clearly show that also for the BM/Hitachi 917 interference exists sometimes, as could be expected because of the chemistries applied. It is a situation that can be found in equivalent analysers as well. The accuracy is acceptable regarding a 95-105% recovery in standard reference material, with the exception of the creatinine Jaffé method. Most of the 160 method comparisons showed acceptable agreement according to our criteria: enzymes, substrates, urine analytes deviation of slope +/- 5%, electrolytes +/- 3%, and proteins and drugs +/- 10%. The assessment of practicability for 14 groups of attributes resulted in a grading of one-three scores better for the BM/Hitachi 917 than the present laboratory situation. In conclusion, the results of the study showed good analytical performance and confirmed the usefulness of the system as a consolidated workstation in medium-sized to large clinical chemistry laboratories.

Evanston Northwestern Healthcare--right hemisphere screen

This article consists of a screening test that has been developed and used by the speech-language pathologists at Evanston Northwestern Healthcare. It is an informal tool designed to quickly determine the cognitive and communication status of right hemisphere-injured patients and is most appropriate for use in acute care and transitional care settings, where speech-language pathologists are asked to determine whether or not a full evaluation is warranted.

Right hemisphere dysfunction: therapeutic intervention from acute care to home health

This article discusses clinical practice variances in speech-language treatment of patients with right hemisphere dysfunction by therapeutic milieu. With an eye toward enhanced cost effectiveness, a model of intervention is presented that takes a patient from acute care management through rehabilitation. Issues discussed include assessment, family training, goal setting, and documentation. A right hemisphere screening tool is included in an appendix for use in acute and transitional care settings where in-depth testing might be inappropriate because of time constraints or the acute or transitory nature of the patient's symptoms.

Activation of tyrosine receptor kinase plays a role in expression of long-term potentiation in the rat dentate gyrus

Long-term potentiation (LTP) in perforant path-granule cell synapses has been shown to be accompanied by an increase in glutamate release. The objective of this study was to examine the possibility that nerve growth factor (NGF), by activating tyrosine kinase, modulates glutamate release and, therefore, contributes to expression of LTP in dentate gyrus. The data indicate that NGF, in the presence of trans-1-aminocyclopentyl-1,3-dicarboxylate (ACPD), enhanced KCI-stimulated release and KCI-stimulated calcium influx in vitro and that these effects were blocked by the tyrosine receptor kinase (trk) inhibitor tyrphostin AG879. The data also indicate that NGF increased phosphorylation of trkA and the mitogen-activated protein kinase extracellular signal-regulated kinase (ERK) in dentate gyrus in vitro. In addition to its effects in vitro, tyrphostin AG879 inhibited the expression of LTP in perforant path-granule cell synapses and the accompanying increase in transmitter release. Analysis of phosphorylation of the two tyrosine kinase substrates trkA and ERK in synaptosomes prepared from untetanized and tetanized dentate gyrus revealed that LTP was associated with increased phosphorylation of both proteins; no evidence of such a change was observed in either tetanized or untetanized tissue prepared from tyrphostin-pretreated rats. These findings are consistent with the hypothesis that NGF, by interacting with trkA, triggers a sequence of tyrosine kinase-dependent phosphorylation steps that modulate glutamate release and calcium influx and impact on expression of LTP in dentate gyrus.

Effects of the forearm support band on wrist extensor muscle fatigue

STUDY DESIGN

A crossover experimental design with repeated measures.

OBJECTIVE

To determine whether the forearm support band alters wrist extensor muscle fatigue.

BACKGROUND

Fatigue of the wrist extensor muscles is thought to be a contributing factor in the development of lateral epicondylitis. The forearm support band is purported to reduce or prevent symptoms of lateral epicondylitis but the mechanism of action is unknown.

METHODS AND MEASURES

Fifty unimpaired subjects (36 men, 14 women; mean age = 29 +/- 6 years) were tested with and without a forearm support band before and after a fatiguing bout of exercise. Peak wrist extension isometric force, peak isometric grip force, and median power spectral frequency for wrist extensor electromyographic activity were measured before and after exercise and with and without the forearm support band. A 2 x 2 repeated measures multivariate analysis of variance was used to analyze the data, followed by univariate analysis of variance and Tukey's multiple comparison tests.

RESULTS

Peak wrist extension isometric force, peak grip isometric force, and median power spectral frequency were all reduced after exercise. However, there was a significant reduction in peak grip isometric force and peak wrist extension isometric force values for the with-forearm support band condition (grip force 28%, wrist extension force 26%) compared to the without-forearm support band condition (grip force 18%, wrist extension force 15%).

CONCLUSIONS

Wearing the forearm support band increased the rate of fatigue in unimpaired individuals. Our findings do not support the premise that wearing the forearm support band reduces muscle fatigue in the wrist extensors.

Hormone-modulating herbs: implications for women's health

Women in the United States are increasingly turning to botanical medicines to treat conditions throughout their life cycles. Many herbs traditionally used for women's health conditions have been found to contain phytoestrogens. Phytoestrogens and their metabolites can bind estrogen receptors and can have both estrogenic and anti-estrogenic effects. Many women are attracted to the idea of using phytomedicine as an alternative to hormone replacement therapy. It is unclear, however, whether these herbs are safe for women at risk for breast cancer or its recurrence. This paper considers the estrogenicity of herbs such as black cohosh (Cimicifuga racemosa) and the implications for women's health.

Methodological problems and the role of statistics in cluster response studies: a framework

More and more citizens urge public health authorities to investigate reports of disease excess in their neighbourhood. These environmental concerns are legitimate and it is part of good public health practice to respond to these complaints. However, the methodological and practical problems are severe and a lot of controversy exists about the usefulness of these investigations. To clarify the possibilities and limitations in this situation, this paper proposes a typology of cluster studies. According to this framework, cluster response is distinguished from two other types of cluster studies: Cluster monitoring. screening proactively for clusters to act as an early warning system, and cluster research, scrutinizing clustering to generate and test aetiological hypotheses. To each of these three types of cluster studies corresponds a different public health context; respectively public health action, public health surveillance and public health research. Probably, part of the controversy mentioned stems from not acknowledging sufficiently the corresponding intrinsic differences in rationality and practical constraints. Cluster response is crisis management and not scientific research. In a relatively short time, an informed decision should be taken by a multidisciplinary team of experts using readily available information and knowledge. In accordance with this point of view, cluster reports should be handled stepwise and the role of statistics is to quantify a cluster exploring different points of view as an input to the decision process.

Stemming the tide: reducing cardiovascular disease and renal failure in Australian Aborigines

An epidemic of cardiovascular disease (CVD) and end stage renal disease (ESRD) has developed among Aborigines in the Northern Territory; CVD deaths increased over the 1980s (tripling among women!), and are now more than five times those of non-Aboriginal people, while ESRD rates are increasing more than 20-fold and are doubling every three to four years. Dialysis costs (>$75,000 per person/year) pose a crisis for health care budgets, but premature mortality is the greater human catastrophe. Health services are not meeting the challenge of timely diagnosis, prevention and containment. We screened 90% of adults (20+ years) in one community, with CVD mortality among the highest in Australia, and ESRD rates increased 60-fold. Seventy-five per cent of persons were smokers. Central obesity was common, but BMIs only modestly increased by Caucasian standards, 23% had hypertension (>140/90), 29% had diabetes or impaired glucose tolerance (IGT) (peaking at 65% of persons aged 40-49 years), high triglyceride and insulin levels were common, and 55% had albuminuria (albumin/creatinine ratio (ACR), >3.4 gm/moL). Progressive albuminuria predicted renal failure. ACR was correlated with age, BMI, blood pressure, lipid, glucose and insulin levels, heavy drinking and past and current skin infections, and, inversely with birth weight. ACR correlated strongly with a composite CV risk score, and in a two to five year follow-up, microalbuminuria (ACR 3.4-33) and overt albuminuria (ACR 34+) have both predicted increased rate of premature death from natural causes of lower ACRs. Thus albuminuria marks CV risk/disease. This implies that renal and CV disease share common risk factors, and should respond to the same interventions, and that this response might be monitored through ACR levels. Robust public health programmes could reduce all these reversible risk factors, lowering disease rates over the intermediate term, however, few such programmes are in place. Modification of disease in persons already afflicted is a parallel responsibility. To this end, in November 1995, we introduced a treatment programme with Coversyl (perindopril, Servier) for all persons in the study community with hypertension (>140/90), for all diabetics with ACR 3.4+ and for all nondiabetic, non-hypertensive persons with progressive overt albuminuria (ACR 34+). One-quarter of all adults, or 224 persons have enrolled; 162 have reached one year of treatment and 100 have passed two years. Compliance is reasonable and enthusiasm high. Average SBP has fallen 12 mmHg (24 mmHg in hypertensive persons), while average ACR and estimated glomerular filtration rate (GFR) have stabilised. This contrasts favourably with the pretreatment course (average 2.7 years) in the same persons, when SBP had increased by 3 mmHg, ACR had increased by 15% and GFR had decreased by 3.5 mL/min each year. Cautious estimates suggest a >50% fall in ESRD, and a reduction in all-cause and CV deaths, even at this early stage, although more extended observation is needed. These data predict a dramatic and rapid fall in morbidity, premature deaths and health care costs if these basic principles of medical care are extended to all Aboriginal people. A national, concerted, multi-disciplinary effort to implement a coherent, effective strategy to this end is of great urgency.

Activation of p42 mitogen-activated protein kinase by arachidonic acid and trans-1-amino-cyclopentyl-1,3- dicarboxylate impacts on long-term potentiation in the dentate gyrus in the rat: analysis of age-related changes

Maintenance of long-term potentiation in perforant path-granule cell synapses is associated with an increase in glutamate release, which we have suggested relies on an interaction between arachidonic acid and the metabotropic glutamate receptor agonist, trans-1-amino-cyclopentyl-1,3-dicarboxylate (ACPD). Evidence suggests that this interaction is dependent on stimulation of tyrosine kinase, which phosphorylates and activates phospholipase Cgamma. In this study, we demonstrate that arachidonic acid and ACPD stimulate tyrosine phosphorylation of a protein of about 40,000 mol. wt and further analysis, using a specific antibody, suggested that this may be extracellular signal-regulated kinase, one member of the family of mitogen-activated protein kinases. Activity of extracellular signal-regulated kinase was increased by arachidonic acid and ACPD in vitro, but it was also increased by induction of long-term potentiation in perforant path-granule cell synapses. A role for extracellular signal-regulated kinase in long-term potentiation was supported by the observation that expression of long-term potentiation, as well as the associated increases in endogenous glutamate release and extracellular signal-regulated kinase activation, were inhibited by pretreatment with the mitogen-activated protein kinase inhibitor, PD98059, while PD98059 pretreatment inhibited the interaction between arachidonic acid and ACPD on glutamate release. An age-related decrease in extracellular signal-regulated kinase activity was observed in the dentate gyrus, and there was no evidence of increased extracellular signal-regulated kinase activity or endogenous glutamate release in tissue prepared from aged rats in which long-term potentiation was compromised. The evidence is consistent with the view that increased activation of extracellular signal-regulated kinase plays a role in long-term potentiation, and that activation of this kinase relies on the interaction between arachidonic acid and ACPD.

Effects of stocking density and concentrate supplementation of grazing dairy cows on milk production, composition and processing characteristics

The effects on milk composition and processing characteristics of varying grass supply by changing stocking density and of offering a concentrate supplement were investigated. The experiment was conducted over 28 weeks of the lactation (April-October) using 48 spring-calved Friesian-Holstein cows. Three herds each of 16 cows were offered a restricted grass supply, a standard grass supply and a standard grass supply with a supplement of 3 kg concentrate/d. Treatment groups were grazed separately with a residence time of 3 d/paddock. Milk production, composition and processing characteristics such as renneting properties, ethanol stability and plasmin activity were measured weekly. Increasing stocking density above the standard system resulted in significant reductions in milk fat and protein yields, the concentrations of total protein, casein and whey proteins, and a deterioration in most processing characteristics. Imposing concentrate supplementation on the standard system increased total protein, casein and whey protein concentrations but generally did not improve processing characteristics except for ethanol stability. These results suggest that the standard grass supply in a rotational grazing paddock system can support efficient production of quality milk, and concentrate supplementation will not improve processing characteristics when an adequate supply of good quality herbage is available.

A nursing intervention to decrease depression in family caregivers of persons with dementia

The goal of this study was to evaluate a community-based psychoeducational-nursing intervention designed to teach home caregivers to manage behavioral problems of persons with Alzheimer's disease and related dementias (ADRD) using the Progressively Lowered Stress Threshold (PLST) model, and to compare this intervention with routine information and referrals for case management, community-based services, and support groups. Previous caregiver studies have overwhelmingly pointed to the adverse effects of caregiving on the caregivers' physical and mental health, and high prevalence rates of depression among caregivers of persons with ADRD have consistently been reported. Therefore, a primary aim was to evaluate the impact of the intervention on caregivers' affective responses, especially depression. Data from both the Profile of Moods States and the Geriatric Depression Rating Scale support the effectiveness of this intervention in decreasing depression among caregivers who received the experimental training. Additional analysis of factors associated with caregiver depression are also reported. The pivotal role of psychiatric nurses in the assessment and treatment of depression among caregivers of persons with ADRD is discussed.

Unfractionated heparin, time for a change?

BACKGROUND

In Ireland physician transfer to utilisation of Low Molecular Weight Heparin for Venous Thromboembolism has been slow, despite evidence of efficacy and concern about the level of anticoagulation achieved with Unfractionated Heparin.

OBJECTIVE

To examine the effectiveness of Unfractionated Heparin administration in a teaching hospital in Ireland. Primary outcomes measured were time to therapeutic APTT and length of hospital stay.

METHODS

We identified 50 consecutive eligible patients treated with continuous intravenous unfractionated heparin for Venous Thromboembolism from the period August 1994 to December 1996 at Beaumont Hospital, Dublin, Ireland. Data analysed included length of hospital stay, costing data and anticoagulation parameters (time to therapeutic APTT, percentage of time within therapeutic range, number of diagnostic tests, heparin dosages).

RESULTS

A significant number of patients (22%) never achieved therapeutic APTT levels. Of those who did achieve therapeutic APTT levels at some time during their therapy, therapeutic range APTT was maintained only 28% of the time on heparin. 57% of the time results were below therapeutic while 15% of the time results were above therapeutic. Also 26% of the patients were discharged with INR results outside the therapeutic range despite an average length of stay of 13.3 days (over twice the ideal of 6 days). Ineffective anticoagulation influenced hospital length of stay in 60% of cases in our evaluation. Average cost of treatment with Unfractionated Heparin was 5897.86 Pounds versus the projected cost of Low Molecular Weight Heparin at 2562.78 Pounds for 6 days of in-patient therapy or 60.78 Pounds for outpatient therapy (excluding physician visit costs).

CONCLUSIONS

Unfractionated Heparin therapy as reviewed in our study is sub-optimal with inadequate anti coagulation and prolonged hospitalisation. Low Molecular Weight heparin, with comparable therapeutic effect documented elsewhere, overall may cost less.

A search for the evidence supporting community paediatric practice

AIM

Controversy exists regarding the evidence base of medicine. Estimates range from 20% to 80% in various specialties, but there have been no studies in paediatrics. The aim of this study was to ascertain the evidence base for community paediatrics.

METHODS

Twelve community paediatricians working in clinics and schools in Yorkshire, Manchester, Teesside, and Cheshire carried out a prospective review of consecutive clinical contacts. Evidence for diagnostic processes, prescribing, referrals, counselling/advice, and child health promotion was found by searching electronic databases. This information was critically appraised and a consensus was obtained regarding quality and whether it supported actions taken.

RESULTS

Two hundred and forty-seven consultations and 1149 clinical actions were performed. Good evidence was found from a randomised controlled trial or other appropriate study for 39.9% of the 629 actions studied; convincing non-experimental evidence for 7%; inconclusive evidence for 25.4%; evidence of ineffectiveness for 0.2%; and no evidence for 27.5%. Prescribing and child health promotion activities had the highest levels of quality evidence, and counselling/advice had the lowest.

CONCLUSIONS

An encouraging amount of evidence was found to support much of community paediatric practice. This study improved on previous research in other specialties because actions other than medications and surgery were included.

Acupressure and the prevention of nausea and vomiting after laparoscopy

The efficacy of currently available antiemetics remains poor. Concern with their side effects and the high cost of the newer drugs has led to renewed interest in non-pharmacological methods of treatment. We have studied the efficacy of acupressure at the P6 point in the prevention of nausea and vomiting after laparoscopy, in a double-blind, randomized, controlled study of acupressure vs placebo. We studied 104 patients undergoing laparoscopy and dye investigation. The anaesthetic technique and postoperative analgesia were standardized. Failure of treatment was defined as the occurrence of nausea and/or vomiting within the first 24 h after anaesthesia. The use of acupressure reduced the incidence of nausea or vomiting from 42% to 19% compared with placebo, with an adjusted risk ratio of 0.24 (95% CI 0.08-0.62; P = 0.005). Other variables were similar between groups.

Factors associated with prolonged symptoms and severe disease due to Clostridium difficile

OBJECTIVE

toxigenic Clostridium difficile is responsible for a spectrum of disease severity ranging from mild diarrhoea to fulminant colitis. This study attempts to determine the proportion of patients in each category of severity and evaluate the risk factors for a more prolonged and complicated course.

DESIGN

prospective cohort study.

SETTING

university teaching hospital.

SUBJECTS

all patients with symptomatic C. difficile infection during 4 months of an outbreak (January-April 1995); n=73; median age 74 years (range 17-91).

MEASUREMENTS

incidence of C. difficile-associated disease (CDAD); severity of disease; percentage of patients in each category of severity; risk factors for severe disease/prolonged symptoms (univariate and multivariable analyses).

RESULTS

the incidence of CDAD was 0.93%. Of the cases identified, 18 (24.7%) had mild, self-limiting disease; 26 (35.6%) had moderately severe disease; 23 (31.5%) had prolonged symptoms and six (8.2%) had a complicated course. Although CDAD was more common in older patients (P < 0.001), increasing age was not a risk factor for severity. Significant risk factors for severe CDAD included low Barthel and abbreviated mental test scores (P < 0.01, P < 0.001 respectively) and recent endoscopy (P=0.03). Logistic regression analysis revealed the following independent predictors of severe CDAD: endoscopy [odds ratios (OR) 4.0, P=0.03] and cognitive impairment (OR 11.0, P < 0.01). A trend towards significance was noted for nasogastric tube insertion (OR 3.1, P=0.08). Complications of infection included dehydration, malnutrition and faecal incontinence (which was statistically significantly associated with more severe disease; P < 0.01).

CONCLUSION

risk factors for severity of CDAD include functional disability, cognitive impairment, and recent endoscopy. Anticipation of severe CDAD may limit morbidity and mortality.

Individual psychopathology and marital distress. Analyzing the association and implications for therapy

This article is a review of the association of individual and marital problems. The focus is on depression, alcohol abuse, anxiety disorders, and the functional psychoses, each of which interact with marital distress in important ways. Although the causal connections between these disorders and marital distress are complex and only particularly understood, the available evidence shows that individuals' and couples' problems often exacerbate each other. Consequently, regardless of whether the initial presentation is individual or couple focused, there is routinely a need to assess both individual and relationship functioning. Couples therapy, and in particular behavioral couples therapy (BCT), is an important element of effective treatment of depression, alcohol abuse, anxiety disorders, and the functional psychoses. The integration of couple and individual therapy presents a number of clinical challenges, and in concluding this article the authors provide guidelines for managing these challenges.

The flavohemoglobin of Escherichia coli confers resistance to a nitrosating agent, a "Nitric oxide Releaser," and paraquat and is essential for transcriptional responses to oxidative stress

Escherichia coli possesses a flavohemoglobin (Hmp), product of hmp, the first microbial globin gene to be sequenced and characterized at the molecular level. Although related proteins occur in numerous prokaryotes and eukaryotic microorganisms, the function(s) of these proteins have been elusive. Here we report construction of a defined hmp mutation and its use to probe Hmp function. As anticipated from up-regulation of hmp expression by nitric oxide (NO), S-nitrosoglutathione (GSNO) or sodium nitroprusside (SNP), the hmp mutant is hypersensitive to these agents. The hmp promoter is more sensitive to SNP and S-nitroso-N-penicillamine (SNAP) than is the soxS promoter, consistent with the role of Hmp in protection from reactive nitrogen species. Additional functions for Hmp are indicated by (a) parallel sensitivity of the hmp mutant to the redox-cycling agent, paraquat, (b) inability of the mutant to up-regulate fully the soxS and sodA promoters in response to oxidative stress caused by paraquat, GSNO and SNP, and (c) failure of the mutant to accumulate reduced paraquat radical after anoxic growth. We conclude that Hmp plays a role in protection from nitrosating agents and NO-related species and oxidative stress. This protective role probably involves direct detoxification of those species and sensing of NO-related and oxidative stress.