Minimal methylation classifier (MIMIC): A novel method for derivation and rapid diagnostic detection of disease-associated DNA methylation signatures

Rapid and reliable detection of disease-associated DNA methylation patterns has major potential to advance molecular diagnostics and underpin research investigations. We describe the development and validation of minimal methylation classifier (MIMIC), combining CpG signature design from genome-wide datasets, multiplex-PCR and detection by single-base extension and MALDI-TOF mass spectrometry, in a novel method to assess multi-locus DNA methylation profiles within routine clinically-applicable assays. We illustrate the application of MIMIC to successfully identify the methylation-dependent diagnostic molecular subgroups of medulloblastoma (the most common malignant childhood brain tumour), using scant/low-quality samples remaining from the most recently completed pan-European medulloblastoma clinical trial, refractory to analysis by conventional genome-wide DNA methylation analysis. Using this approach, we identify critical DNA methylation patterns from previously inaccessible cohorts, and reveal novel survival differences between the medulloblastoma disease subgroups with significant potential for clinical exploitation.

Routine cognitive screening in older patients admitted to acute medicine: abbreviated mental test score (AMTS) and subjective memory complaint versus Montreal Cognitive Assessment and IQCODE

Introduction: routine cognitive screening for in-patients aged ≥75 years is recommended, but there is uncertainty around how this should be operationalised. We therefore determined the feasibility and reliability of the Abbreviated mental test score (AMTS/10) and its relationship to subjective memory complaint, Montreal Cognitive Assessment (MoCA/30) and informant report in unselected older admissions.

Methods: consecutive acute general medicine patients aged ≥75 years admitted over 10 weeks (March–May 2013) had AMTS and a question regarding subjective memory complaint (if no known dementia/delirium). At ≥72 h, the 30-point Montreal Cognitive Assessment (MoCA) and Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) were done. Cognitive impairment was defined as AMTS < 9 or MoCA < 26 (mild impairment) and MoCA < 20 (moderate/severe impairment) or IQCODE ≥ 3.6.

Results: among 264 patients (mean age/SD = 84.3/5.6 years, 117 (44%) male), 228 (86%) were testable with AMTS. 49/50 (98%) testable patients with dementia/delirium had low AMTS compared with 79/199 (44%) of those without (P < 0.001). Subjective memory complaint agreed poorly with objective cognitive deficit (39% denying a memory problem had AMTS < 9 (kappa = 0.134, P = 0.086)) as did informant report (kappa = 0.18, P = 0.15). In contrast, correlation between AMTS and MoCA was strong (R² = 0.59, P < 0.001) with good agreement between AMTS < 9 and MoCA < 20 (kappa = 0.50, P < 0.01), although 85% of patients with normal AMTS had MoCA < 26.

Conclusions: the AMTS was feasible and valid in older acute medicine patients agreeing well with the MoCA albeit with a ceiling effect. Objective cognitive deficits were prevalent in patients without known dementia or delirium but were not reliably identified by subjective cognitive complaint or informant report.

Medically assisted hydration for palliative care patients

BACKGROUND

Many palliative care patients have reduced oral intake during their illness. The management of this can include the provision of medically assisted hydration with the aim of prolonging the length of life of a patient, improving their quality of life, or both.

OBJECTIVES

To determine the effect of medically assisted hydration in palliative care patients on their quality and length of life.

SEARCH STRATEGY

Studies were identified from searching CENTRAL, MEDLINE (1966 to 2008), EMBASE (1980 to 2008), CINAHL, CANCERLIT, Caresearch, Dissertation abstracts, SCIENCE CITATION INDEX and the reference lists of all eligible studies, key textbooks, and previous systematic reviews. The date of the latest search was February 2008.

SELECTION CRITERIA

All relevant randomised controlled trials (RCTs) or prospective controlled studies of medically assisted hydration in palliative care patients.

DATA COLLECTION AND ANALYSIS

Five relevant studies were identified. These included two RCTs (93 participants), and three prospective controlled trials (360 participants). These were assessed independently by two review authors for quality and validity. The small number of studies and the heterogeneity of the data meant that a quantitative analysis was not possible, so a description of the main findings was included only.

MAIN RESULTS

One study found that sedation and myoclonus (involuntary contractions of muscles) were improved more in the intervention group (28 - hydration, 23 - placebo). Another study found that dehydration was significantly higher in the non-hydration group, but that some fluid retention symptoms (pleural effusion, peripheral oedema and ascites) were significantly higher in the hydration group (59 - hydration group, 167 - non -hydration group). The other three studies did not show significant differences in outcomes between the two groups.

AUTHORS' CONCLUSIONS

There are insufficient good quality studies to make any recommendations for practice with regard to the use of medically assisted hydration in palliative care patients.

A basic study of some normoxic polymer gel dosimeters

Polymer gel dosimeters offer a wide range of potential applications in the three-dimensional verification of complex dose distribution such as in intensity-modulated radiotherapy (IMRT). Until now, however, polymer gel dosimeters have not been widely used in the clinic. One of the reasons is that they are difficult to manufacture. As the polymerization in polymer gels is inhibited by oxygen, all free oxygen has to be removed from the gels. For several years this was achieved by bubbling nitrogen through the gel solutions and by filling the phantoms in a glove box that is perfused with nitrogen. Recently another gel formulation was proposed in which oxygen is bound in a metallo-organic complex thus removing the problem of oxygen inhibition. The proposed gel consists of methacrylic acid, gelatin, ascorbic acid, hydroquinone and copper(II)sulphate and is given the acronym MAGIC gel dosimeter. These gels are fabricated under normal atmospheric conditions and are therefore called 'normoxic' gel dosimeters. In this study, a chemical analysis on the MAGIC gel was performed. The composition of the gel was varied and its radiation response was evaluated. The role of different chemicals and the reaction kinetics are discussed. It was found that ascorbic acid alone was able to bind the oxygen and can thus be used as an anti-oxidant in a polymer gel dosimeter. It was also found that the anti-oxidants N-acetyl-cysteine and tetrakis(hydroxymethyl)phosphonium were effective in scavenging the oxygen. However, the rate of oxygen scavenging is dependent on the anti-oxidant and its concentration with tetrakis(hydroxymethyl)phosphonium being the most reactive anti-oxidants. Potentiometric oxygen measurements in solution provide an easy way to get a first impression on the rate of oxygen scavenging. It is shown that cupper(II)sulphate operates as a catalyst in the oxidation of ascorbic acid. We, therefore, propose some new normoxic gel formulations that have a less complicated chemical formulation than the MAGIC gel.

Clinical evaluation of an automatic flossing device vs. manual flossing

The aim of this study was to compare the effectiveness of an automatic flossing device to manual flossing. A total of seventy adult subjects (20 males and 50 females) were stratified into two groups balanced for age, sex, modified gingival index (MGI), plaque index (PI) and bleeding sites (Eastman Bleeding Index) using screening data. One group was randomly assigned the automatic power flosser and the other group was assigned manual dental floss. The subjects were instructed to brush their teeth twice a day (in the morning and before bedtime) for 30 seconds using the provided manual toothbrush and toothpaste. They were also to use their assigned dental floss or automatic power flosser once in the morning following toothbrushing. There was no significant difference between manual flossing and automatic flossing with respect to the MGI and the BI. There was, however, a significant difference at day 15 in the PI; however, this difference was only 0.73%. There was no significant difference in the PI at day 30 between the two techniques. The statistically significant difference noted in the interproximal PI at both day 15 and day 30 was less than 2%. Since the differences in plaque scores between the groups were so small, there was no apparent impact on gingival health since both flossers resulted in similar health benefits. Since there was a marked preference for the automatic flosser, patient compliance with the automatic flossing device may be better than with manual floss. Therefore, overall gingival health may benefit from this device.

How events are reviewed matters: effects of varied focus on eyewitness suggestibility

Witnesses to a crime or an accident perceive that event only once, but they are likely to think or talk about it multiple times. The way in which they review the event may affect their later memory. In particular, some types of review may increase suggestibility if the witness has been exposed to postevent misleading information. In Experiment 1, participants viewed a videotaped crime and then received false suggestions about the event. We found that participants who were then asked to focus on specific details when reviewing the event were more suggestible on a later source memory test than participants asked to review the main points. The findings of Experiment 2 suggest that this effect was not due to a criterion shift at test. These findings indicate that the type of rehearsal engaged in after witnessing an event can have important consequences for memory and, in particular, suggestibility.

Choice-supportive source monitoring: do our decisions seem better to us as we age?

Participants were given several 2-option choices and then asked to review how they felt about their decisions, to review the details of their decisions, or to do an unrelated task. When later asked to attribute features to the previous options, in each condition older adults (64-83 years) attributed significantly more positive and fewer negative features to their chosen options than to foregone options. Younger adults' (18-22 years) attributions were as choice-supportive as those of older adults in the affective review condition but were less so in the other conditions. The age difference was present even when older and younger adults were equated for source identification and recognition accuracy. This study suggests that as people age, their tendency to distort memory in favor of the options they chose increases. In addition, it suggests that affectively reviewing choices increases younger adults' tendency toward choice-supportive memory.

Polycations induce the release of soluble intermembrane mitochondrial proteins

The release of proapoptotic proteins from the intermembrane space of mitochondria is an early critical step in many pathways to apoptosis. Induction of the mitochondrial permeability transition pore (PTP) was suggested to be the mechanism of the release of soluble mitochondrial intermembrane proteins (SIMP) in apoptosis. However, several studies suggested that proapoptotic proteins (e.g. Bax and Bid) can induce the release of SIMP (e.g. cytochrome c (cyt c) and adenylate kinase 2 (AK2)) in vivo and in vitro independent of PTP. We have found that a number of structurally diverse polycations, such as aliphatic polyamines (e.g. spermine and to a lesser extent spermidine), aminoglycosides (e.g. streptomycin, gentamicin and neomycin), and cytotoxic peptides (e.g. melittin), induce the release of SIMP from liver mitochondria, in vitro. All the polycations released AK2 together with cyt c, suggesting that rupture of the outer membrane is a common mechanism of cyt c release by these polycations. Several polycations (e.g. spermine, spermidine and neomycin) induced SIMP release without inducing significant swelling, and this release was not inhibited significantly by the PTP inhibitor cyclosporin. In contrast, under the same conditions, streptomycin and melittin induced swelling and SIMP release that was inhibited strongly by cyclosporin. Gentamicin-induced swelling and release of SIMP were partially inhibited by cyclosporin. The affinity of polyamines to the anionic phospholipids of the mitochondrial membranes (spermine=neomycin>gentamicin>streptomycin=spermidine) correlated roughly with their ability to induce PTP-independent release of SIMP, which suggests that the binding of polycations to the anionic phospholipids of the outer mitochondrial membrane facilitates the rupture of this membrane. However, some polycations facilitated the induction of PTP, possibly by binding to cardiolipin on the inner membrane. This dual mechanism may be relevant to the induction of SIMP release in apoptosis.

Choice-supportive source monitoring: do our decisions seem better to us as we age?

Participants were given several 2-option choices and then asked to review how they felt about their decisions, to review the details of their decisions, or to do an unrelated task. When later asked to attribute features to the previous options, in each condition older adults (64-83 years) attributed significantly more positive and fewer negative features to their chosen options than to foregone options. Younger adults' (18-22 years) attributions were as choice-supportive as those of older adults in the affective review condition but were less so in the other conditions. The age difference was present even when older and younger adults were equated for source identification and recognition accuracy. This study suggests that as people age, their tendency to distort memory in favor of the options they chose increases. In addition, it suggests that affectively reviewing choices increases younger adults' tendency toward choice-supportive memory.

Aging and reflective processes of working memory: binding and test load deficits

It was hypothesized that age-related deficits in episodic memory for feature combinations (e.g., B. L. Chalfonte & M. K. Johnson, 1996) signal, in part, decrements in the efficacy of reflective component processes (e.g., M. K. Johnson, 1992) that support the short-term maintenance and manipulation of information during encoding (e.g., F. 1. M. Craik. R. G. Morris. & M. L. Gick, 1990; T. A. Salthouse, 1990). Consistent with this, age-related binding deficits in a working memory task were found in 2 experiments. Evidence for an age-related test load deficit was also found: Older adults had greater difficulty than young adults when tested on 2 features rather than 1, even when binding was not required. Thus, disruption of source memory in older adults may involve deficits in both encoding processes (binding deficits) and monitoring processes (difficulty accessing multiple features, evaluating them, or both).

Aging enhances the activation of the permeability transition pore in mitochondria

Aging is associated with mitochondrial dysfunction in several tissues. However, it is not known how the observed mitochondrial dysfunction is related to aging-associated tissue degeneration. We have shown previously that the activation of the permeability transition pore (PTP), which is believed to play a critical role in cell necrosis and apoptosis, is enhanced in spleen lymphocytes from old mice. Here we show that the threshold for calcium-induced, cyclosporin-sensitive, calcium release was significantly lower in isolated brain and liver mitochondria from aging mice. Thus, aging mice exhibit enhanced PTP activation in lymphocytes, brain, and liver. These results suggest that aging increases the susceptibility to calcium-dependent cell death (e.g., excitotoxicity, ischemia-reperfusion damage) in the brain, liver, and possibly other tissues. In addition, other pathways to apoptosis or necrosis that depend on PTP activation are also likely to be enhanced by aging.

Misremembrance of options past: source monitoring and choice

This study reveals that when remembering past decisions, people engage in choice-supportive memory distortion. When asked to make memory attributions of options' features, participants made source-monitoring errors that supported their decisions. They tended to attribute, both correctly and incorrectly, more positive features to the option they had selected than to its competitor. In addition, they sometimes attributed, both correctly and incorrectly, more negative features to the nonselected option. This pattern of distortion may be beneficial to people's general well-being, reducing regret for options not taken. At the same time, it is problematic for memory accuracy, for accountability, and for learning from past experience.

Adoption: a forgotten paediatric speciality

OBJECTIVE

To study the medical, emotional, and developmental profile of children being considered for permanent substitute care.

DESIGN

A retrospective analysis of 100 adoption/permanency medicals.

SETTING

All children considered by the adoption and permanency panel in Greenwich, south east London, between 1994 and 1998.

OUTCOME MEASURES

Analysis of medical reports completed using the British Agencies for Adoption and Fostering form C (under 5 years) or form D (over 5 years). These include the details of a physical examination, including vision, hearing, height, and weight; emotional and behavioural concerns expressed by the foster carer and school progress.

RESULTS

These children have complex needs. Only 31 of the 100 children were considered unlikely to have significant medical, developmental, or emotional problems.

CONCLUSIONS

Adoption medical work is becoming more specialised. Healthcare commissioners should establish minimum standards for the doctors involved in this work. As the NHS moves towards becoming a more primary care led organisation, this small service must not be forgotten. The NHS devotes few resources and little training to adoption. The medical input required to support adoption and fostering services should be recognised as a specialist paediatric service and adequately resourced.

Evaluating characteristics of false memories: remember/know judgments and memory characteristics questionnaire compared

Subjects hearing a list of associates to a nonpresented lure word later often claim to have heard the lure (Deese, 1959; Roediger & McDermott, 1995). To examine the characteristics of such false memories, subjects completed a memory characteristics questionnaire (MCQ; Johnson, Foley, Suengas, & Raye, 1988) or made remember/know (RK; Gardiner & Java, 1993) judgments for previously heard theme associates and nonpresented lures. MCQ ratings indicated that false memories for lures had less auditory detail and less remembered feelings and reactions than memories for presented words. In addition, rates of false recognition for lures were significantly lower than rates of correct recognition when items from various themes were intermixed instead of blocked at acquisition and subjects made MCQ ratings instead of RK judgments. This demonstrates that false memories can be affected both by how they are acquired and by how extensively they are examined at retrieval.

Unconscious influences on amnesics' word-stem completion

Amnesic patients and control subjects were asked to complete three-letter word-stems under one of three retrieval conditions. In a direct condition, they were told to use the stems as retrieval cues for words that had just been presented in a study list. In an indirect condition, they were told to use the first word that came to mind with no reference made to the study list. Finally, in an oppositional condition, they were told to use the first word that came to mind unless it had appeared on the study list. During the study list presentation, the patients and controls had analyzed each word according to either semantic (associating to each word) or graphemic (counting letters with enclosed spaces) instructions. The results revealed that the control subjects produced a different number of study words during retrieval as a function of retrieval instructions and encoding condition. The amnesics, however, did not vary their performance as a function of retrieval instructions. Under all conditions, they completed the word-stems far more frequently with words from the study list than would be expected by chance and they consistently produced more semantic than graphemic responses. We concluded that semantic analysis might affect the fluency with which an item occurs for the amnesic, but that the item itself remains independent of the source of that fluency for these patients. Thus, the level of analysis performed on a word during study can affect the unconscious performance of amnesic patients but is unavailable for use during conscious retrieval.

The effect of an antiseptic mouthrinse on implant maintenance: plaque and peri-implant gingival tissues

The purpose of this controlled double-blind, parallel, randomized clinical study was to determine the effect of antiseptic mouthrinse on parameters important to dental implant maintenance. Plaque, peri-implant gingivitis, gingival bleeding, probing depth, and attachment level were assessed over a 3-month test period. Twenty healthy adult patients each of whom had at least two dental implants, a modified gingival index > 1.5, and a modified Quigley-Hein plaque index score > 1.7 were enrolled into the study. After a thorough oral prophylaxis, patients were randomly assigned to either the antiseptic mouthrinse or a 5% hydroalcohol placebo mouthrinse group and instructed to rinse twice daily for 30 seconds with 20 ml of their assigned mouthrinse as an adjunct to their usual oral hygiene procedures. The baseline examination included plaque index, gingival index, bleeding index, probing depth measurement, and attachment level measurements. The plaque and gingival indices were rescored at 1, 2, and 3 months. Probing depths, attachment levels, and bleeding index were determined again at 3 months only. At the end of 3 months, the antiseptic mouthrinse group had statistically significant reductions in plaque index, gingival index, and bleeding index compared to the placebo group. There were no significant differences between groups in probing depth or attachment level. The results of this clinical study indicate that twice daily use of an antiseptic mouthrinse may provide benefits in the maintenance of dental implants.

Problems of overseas adoption

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An alternative to dental floss in a personal dental hygiene program

The concept of gingival massage on maintaining the health of the gingiva may be of value as an adjunct in the periodontal maintenance phase of treatment. This study compared dental floss to a test product, a massage device, in a randomized population of 20 male and female subjects. Clinical measurements were taken at baseline, week 3, and week 6. Patients were instructed to brush twice daily using their normal hygiene methods and to use the assigned product once daily. Plaque index (PI), bleeding index (BI) and pocket probing depths did improve in both the control and the test groups, but the differences did not favor either group over the other. The gingival index (GI) did, however, significantly decrease in the massage group, suggesting that this product may not only be an alternative to dental floss, but may provide added benefits from gingival massaging.

Improved diagnostics: clinical evaluation of a color-coded, polymeric periodontal probe

The objective of this study was to compare the accuracy, reproducibility and patient comfort of a newly designed, color-coded, polymeric periodontal probe to a traditional, color-coded metal probe. Twenty-four adult subjects with varying degrees of periodontal disease (from slight to severe) reported for two visits, one week apart. A randomization schedule for probe use was adopted over the two visits so that the gingival crevices in two quadrants were probed with the same probe (metal or polymeric) providing reproducibility information for each probe, while the other two quadrants were probed first with one probe then the other for comparison data yielding information on accuracy. A bleeding index was obtained using the same schedule. Clinical scoring was performed by the same examiner. After probing each quadrant, subjects rated discomfort using a visual analog scale (VAS). Results showed no significant difference in depth readings greater than 2 mm between the polymeric and metal probes (3.41 +/- 0.37 mm vs. 3.38 +/- 0.32 mm, p = 0.55). Significantly less discomfort (assessed by VAS) was recorded by patients after polymeric probe use (3.70 +/- 2.40 cm vs. 4.44 +/- 2.49 cm, p = 0.015). The bleeding index indicated significantly less bleeding with the polymeric probe (0.80 +/- 0.56 vs. 1.24 +/- 0.65, p = 0.0001). Both the polymeric and metal probes were found to produce highly reproducible results in all measures across visits.

Clinical evaluation of anticalculus dentifrices

One hundred and eighty-seven patients participated in a six-month study to evaluate the calculus-inhibiting effect of a zinc citrate dentifrice compared to Crest Tartar Control and a placebo, Crest Regular. The findings demonstrate a statistically significant calculus prevention benefit over Crest Regular for both Crest Tartar Control and a 2% zinc citrate/silica product. Compared to the control, the zinc citrate product reduced calculus formation by 32.3%, and Crest Tartar Control reduced it by 21.4%. These findings also demonstrate no statistically significant difference in stain or soft tissue status among the three dentifrices. All products were found to be safe to oral tissues and acceptable for taste.

A survey of drug prescribing practices of dentists

A survey of drug prescribing habits of 357 dentists practicing in five counties in Western New York was conducted in 1986. Respondents represented both general practitioners and specialists who were graduates of 25 different dental schools. From this study it can be concluded that dentists prescribe a wide range of drugs representing over 13 drug categories. The most frequently prescribed drug categories were antibiotics, narcotic analgesics, non-steroidal inflammatory agents, non-narcotic analgesics, and fluorides. The most frequent prescribers of drugs were oral surgeons, endodontists and periodontists.

The nucleotide sequence of the cyd locus encoding the two subunits of the cytochrome d terminal oxidase complex of Escherichia coli

The cytochrome d terminal oxidase complex is one of two terminal oxidases in the aerobic respiratory chain of Escherichia coli. The enzyme is located in the cytoplasmic membrane where it oxidizes ubiquinol-8 in the bilayer and reduces oxygen to water. Enzyme turnover is coupled to the generation of a proton-motive force, resulting in electrogenic translocation across the membrane of one proton per electron passing through the system. The enzyme is an alpha beta heterodimer containing four hemes. The cyd locus, encoding both subunits, has previously been genetically mapped and cloned. This work describes an insertion and deletion analysis of cyd which indicates the direction of transcription, defines the coding regions, and suggests that cyd is an operon. In addition, the complete DNA sequence of the cyd gene is reported. Two open reading frames, separated by 18 base pairs, encode the two subunits of the oxidase complex. Hydropathy profiles of the deduced protein sequence indicate that subunits I and II are each likely to have multiple transmembrane elements. There are only 10 histidines in both subunits, several of which are likely to serve as heme axial ligands.

Studies of the flavin adenine dinucleotide binding region in Escherichia coli pyruvate oxidase

Experiments have been performed to probe the flavin adenine dinucleotide (FAD) binding region in Escherichia coli pyruvate oxidase. This enzyme functions as a membrane-associated flavoprotein coupled to the aerobic E. coli respiratory chain. The FAD moiety is noncovalently bound to pyruvate oxidase and can be removed reversibly to form apopyruvate oxidase. The addition of free FAD to apoenzyme results in the stoichiometric re-formation of the active flavoprotein. Using this technique, synthetic analogs of FAD were substituted in the flavin binding site and used as structural probes. Spectral analysis indicates that the benzoquinoid forms of 8-mercapto-FAD and 6-hydroxy-FAD are stabilized in the enzyme-binding site. This is consistent with the fact that the native flavoprotein forms a red (anion) radical upon photoreduction. These data suggest that the isoalloxazine ring may be poised for reduction via position N-5 by a carbanionic intermediate. The alpha-carbanion of hydroxyethylthiamin pyrophosphate, formed following the decarboxylation of pyruvate, is a likely candidate. The highly resolved visible spectrum of the native flavoprotein suggests that the flavin is buried in a hydrophobic environment. Reactivity studies using 8-chloro-FAD-pyruvate oxidase and 2-thio-FAD-pyruvate oxidase suggest that the C-8 position and C-2 position of the isoalloxazine ring may not be accessible to the solvent. Spectral perturbations observed with 6-hydroxy-FAD-pyruvate oxidase indicate, however, that the isoalloxazine C-6 position may be located near the binding site for the cofactor thiamin pyrophosphate. Restrictions to the accessibility of the active site of the enzyme are suggested by the fact that sulfite does not form an adduct with the flavin in the native enzyme.

Conformational studies of Escherichia coli pyruvate oxidase

Pyruvate oxidase (pyruvate:oxygen oxidoreductase (phosphorylating), EC 1.2.3.3) is a peripheral membrane enzyme from Escherichia coli which utilizes the cofactors thiamin pyrophosphate (TPP) and flavin-adenine dinucleotide (FAD) to catalyze the decarboxylation of pyruvate to acetic acid and carbon dioxide. The specific activity of the oxidase is enhanced 25-fold when assayed in the presence of certain lipids and detergents. Previous studies have demonstrated that the affinity of pyruvate oxidase for phospholipids and detergents is substantially increased when the flavin is reduced. In this paper, several techniques are utilized to probe both the nature of the active site and the conformational changes in the protein which are concomitant with flavin reduction and with the binding of lipids to the enzyme. Analysis of the circular dichroism spectrum in the far ultraviolet region indicates that neither the binding of lipid activators to the oxidase nor reduction of the enzyme-bound flavin by pyruvate has a significant effect on the average secondary structure of the enzyme. High-resolution electron microscopy demonstrates that at low enzyme concentrations, i.e., assay conditions, incubation of the reduced flavoprotein in the presence of an amphiphilic activator does not alter the quaternary structure of pyruvate oxidase. The results indicate that the conformational changes in the protein due either to reduction of the flavin or to the binding of lipid activators are localized.

Reality orientation, a therapy for psychogeriatric patient: a controlled study

In a controlled trial, ‘reality orientation’ for elderly patients diagnosed as suffering from dementia is shown to be effective only where therapists actively participate. Exposure to change in a more stimulating environment than their own wards is not enough to produce sustained improvement.