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Biomedical subjects

J Keene

Publications and source records attributed to J Keene.

At least 37 records · Page 2Linked to original sources
PubMed1999

Natural history of behavioural changes and psychiatric symptoms in Alzheimer's disease. A longitudinal study.

BACKGROUND: Alzheimer's disease and other types of dementia are characterised by numerous psychiatric and behavioural changes. Little is known of their natural history. AIMS: To investigate the sequence and pattern of these changes throughout the course of dementia. METHOD: One hundred people, initially living at home with carers, entered a prospective, longitudinal study. At four-monthly intervals, behavioural and psychiatric symptoms were assessed using the Present Behavioural Examination and Mini-Mental State Examination. Follow-up continued for up to nine years (mean 3.3 years; s.d. 2.4). Patterns of onset and disappearance of these symptoms, their sequence and association with time of death and cognitive decline were analysed. Autopsy confirmed a diagnosis of pure Alzheimer's disease in 48 subjects. Data for this subgroup are presented. RESULTS: Some changes tend to occur earlier than others but changes can occur at almost any time in the course of dementia. CONCLUSIONS: The natural history of behaviour changes in Alzheimer's disease shows great individual variation although some changes tend to follow a recognisable sequence.

Aged↗
PubMed1999

The relevance of problems and models to treatment outcome: a comparative study of two agencies.

The aim of this study was to compare the progress of clients attending two substance misuse treatment agencies. A wide range of problems were recorded at 1, 3-6, and 12 month intervals; these included measures of substance misuse and dependence together with social problems and physical and mental health problems. Differences in outcome between the two agencies were entirely attributable to the number and severity of a range of problems rather than simply to severity of dependence or differences between the agencies themselves. This raised questions of how treatment outcomes are understood and explained, and the usefulness of therapeutic models per se.

Adaptation, Psychological↗
PubMed1998

An investigation of satiety in ageing, dementia, and hyperphagia.

OBJECTIVE: To investigate satiety in young, middle-aged, and elderly healthy adults, and in nonhyperphagic and hyperphagic elderly people with dementia. Previous work suggested hyperphagia in dementia was due to increased hunger and absence of satiation. METHODS: The primary measure of satiety was the amount of food eaten in an ad libitum meal, given 1 hr after a fixed preload. Three types of preload were used, high- and low-energy milkshakes and water. The effect of age was investigated by comparing the three groups of healthy adults. The effect of dementia was investigated by comparing the two demented groups with healthy elderly. RESULTS: Measurements suggested that accuracy of compensation for preload energy differences decreased with age and was absent in people with dementia. DISCUSSION: Lack of compensatory response in the elderly, particularly those with dementia, indicates the need for monitoring food intake to prevent over- or undereating.

Adult↗
PubMed1998

Predictors of institutionalization for people with dementia living at home with a carer.

OBJECTIVE: This article examines the relationships between behaviour, psychological functioning, the caring environment and subsequent institutionalization in patients with dementia living at home with a carer. DESIGN: Longitudinal study of behaviour in dementia, with a nested case-control study to investigate predictors of institutionalization. SETTING: Subjects with dementia, known to service, living at home with a carer. All lived in Oxfordshire, UK. PARTICIPANTS: 100 people with dementia (Alzheimer's disease and/or vascular dementia) who were living at home with a carer at the start of the study. MEASURES: At 4-monthly intervals, the carers were interviewed and the subjects with dementia were assessed cognitively. Subjects' behaviour and psychological functioning were assessed using the Present Behavioural Examination. RESULTS: The characteristics which best predicted institutionalization 1 year later were: excessive night-time activity; immobility or difficulty in walking; incontinence; being away from a carer for more than 16 hours a week; and being cared for by a female. Aggressive behaviour was not associated with an increased chance of entry into an institution 1 year later, although it was more prevalent 4 months before entering an institution. CONCLUSIONS: Both behaviour and psychological functioning and the caring environment can help in predicting which patients with dementia currently living at home will enter an institution 1 year later. These predictors are not the same as those which are the immediate cause of institutionalization.

Activities of Daily Living↗
PubMed1998

Natural history of hyperphagia and other eating changes in dementia.

OBJECTIVE: To investigate the natural history of overeating (hyperphagia) and its elements during the course of dementia. DESIGN: Prospective longitudinal study of overeating (hyperphagia) in dementia. Two studies were carried out: (1) hyperphagia and associated eating changes were investigated as part of a larger prospective 10-year study into behaviour changes, using carers' reports; (2) an observational study to investigate hyperphagia quantitatively; this took place over the course of a year by means of direct observation of test meals in a normal environment. SETTING: Subjects with dementia living in Oxfordshire, UK. PARTICIPANTS: (1) 99 people with dementia, living at home with a carer, with data for more than 1 year. (2) Nine people with a diagnosis of Alzheimer's disease who were hyperphagic. MEASURES: (1) The Present Behavioural Examination was used at 4-monthly intervals to assess the subjects' behaviour and psychological functioning. (2) Food intake, macronutrient choice and the microstructure of eating were measured using a standardized test meal. RESULTS: (1) Severe or persistent hyperphagia was reported in 23% of the sample and carers reported a clear onset to hyperphagia with a median duration of 16 months. (2) From direct observation, each person who was hyperphagic was seen to maintain a constant eating rate in test meals during the course of a year but meals ended earlier as hyperphagia decreased. CONCLUSIONS: Hyperphagia is common in dementia, it occurs over a single restricted period, mainly during the middle stages of dementia, and is not significantly related to age, sex, diagnosis, medication or activity.

Aged↗
PubMed1998

Psychiatric symptoms in patients with dementia predict the later development of behavioural abnormalities.

BACKGROUND: Cross-sectional studies of non-cognitive symptoms in dementia show that patients with psychotic symptoms tend to have more disturbed behaviour. However, it is not known whether individuals who experience psychiatric symptoms early in dementia are more prone to develop behavioural problems later in the illness. METHOD: The behaviour of 86 community-dwelling subjects with dementia was intensively studied for 4 years or until death, using an informant interview which was administered every 4 months on a median of eight occasions. The extent to which psychiatric symptoms, age, sex and cognitive function predicted clinically significant physical aggression or motor hyperactivity was assessed. RESULTS: Physical aggression was predicted by sad appearance and motor hyperactivity was predicted by persecutory ideas. These associations were robust, remaining significant over 2, 3 and 4 years of follow-up and were independent of cognitive function, age, sex and duration of illness. CONCLUSIONS: There may be two distinct longitudinal syndromes of non-cognitive symptoms in dementia. This suggests that important aberrant behaviours in late dementia may share pathophysiological mechanisms with psychiatric symptoms in early dementia.

Aged↗
PubMed1998

Getting lost in dementia: a longitudinal study of a behavioral symptom.

The occurrence of episodes of getting lost was examined in 104 subjects with dementia who were assessed every 4 months over 5 years. All subjects were initially living at home with a caregiver who could give good information. Forty-three subjects needed to be brought back home at least once. Five subjects repeatedly got lost. Forty-six subjects were kept behind locked doors at some point. Subjects who got lost were more likely to become permanently resident in institutions (odds ratio = 7.3; 95% confidence interval: 3.0 to 17.8). Patients who performed better on a behavioral test of topographical memory were less likely to get lost over the subsequent 5 years (negative predictive value: 90%). The risk of patients with dementia getting lost is substantial and requires frequent intervention by caregivers. This risk is a major reason for institutionalization. A simple test may help in assessing the risk of getting lost in patients with dementia.

Aged↗
PubMed1997

Do neuroleptic drugs hasten cognitive decline in dementia? Prospective study with necropsy follow up.

OBJECTIVE: To investigate the contribution of neuroleptic drugs to cognitive decline in dementia. DESIGN: Two year prospective, longitudinal study consisting of interviews every four months, with necropsy follow up. SETTING: Community settings in Oxfordshire. SUBJECTS: 71 subjects with dementia, initially living at home with informant. MAIN OUTCOME MEASURES: Cognitive function (score from expanded minimental state examination); behavioural problems (physical aggression, hallucinations, persecutory ideas, and disturbance of diurnal rhythm); and postmortem neuropathological assessment (cortical Lewy body pathology). RESULTS: The mean (SE) decline in cognitive score in the 16 patients who took neuroleptics was twice that in the patients who did not (20.7 (2.9) v 9.3 (1.3), P = 0.002). An increased rate of decline was also associated with aggression, disturbed diurnal rhythm, and persecutory ideas. However, only use of neuroleptics and severity of persecutory ideas were independently associated with more rapid cognitive decline when all other variables were adjusted for. The start of neuroleptic treatment coincided with more rapid cognitive decline: median rate of decline was 5 (interquartile range 8.5) points per year before treatment and 11 (12) points per year after treatment (P = 0.02). Cortical Lewy body pathology did not account for association between neuroleptic use and more rapid decline. CONCLUSIONS: Neuroleptic drugs that are sometimes used to treat behavioural complications of dementia may worsen already poor cognitive function. Randomised controlled trials are needed to confirm a causal relation.

Aged↗
PubMed1997

Behaviour changes in dementia. 1: Point of entry data of a prospective study.

OBJECTIVE: This article analyses behaviour changes in dementia at the point of entry to a longitudinal study. DESIGN: Prospective, longitudinal study of behaviour in dementia, with autopsy follow-up. SETTING: Subjects with dementia, living at home with a carer. All lived in Oxfordshire, UK. PARTICIPANTS: Ninety-seven people with dementia (Alzheimer's disease and/or vascular dementia) who were living at home with a carer. MEASURES: At 4-monthly intervals, the carers were interviewed and the subjects with dementia were assessed cognitively. Subjects' behaviour was assessed using the Present Behavioural Examination. This is an investigator-based, semi-structured interview consisting of eight main sections covering many different aspects of behaviour. The 121 main questions, with 66 further 'nested' questions, have been shown to have high reliability. RESULTS: This article analyses the types of behaviour change reported by carers at the point of entry to this long-term study. Few correlations were found between behaviour and age, gender and time since onset of dementia. Some types of behaviour were significantly more prevalent in those with greater cognitive impairment. CONCLUSIONS: Many of these changes create problems for carers, for example increased aggressive behaviour, wandering, wakefulness at night, incontinence and persecutory ideas. In general, they are more prevalent in people with more severe dementia.

Aged↗
PubMed1997

Behaviour changes in dementia. 2: Are there behavioural syndromes?

OBJECTIVE: To establish whether robust behavioural 'syndromes' can be identified from among the widely heterogeneous behavioural changes which occur in dementia. DESIGN: Longitudinal, prospective study with follow-up at 4 and 8 months. SETTING: Community settings in Oxfordshire, UK. PARTICIPANTS: 97 elderly people with a diagnosis of Alzheimer's disease or vascular dementia (in many cases confirmed by postmortem examination) and who were living at home with a carer. MEASURES: Each subject's behaviour was assessed in detail at each interview using the Present Behavioural Examination to assess subject's behaviour over the preceding 4 weeks. Seventeen key behaviour items which were both common and clinically important were selected for further analysis. RESULTS: Three syndromes were identified: (a) overactivity (walking more, walking aimlessly, trailing the carer or checking where the carer was); (b) aggressive behaviour (physical aggression, aggressive resistance, verbal aggression); (c) psychosis (anxiety, persecutory ideas and hallucinations). The same syndromes were found using data collected at three different time points and by using a variety of statistical techniques, confirming their robustness. CONCLUSIONS: Overactivity, aggressive behaviour and psychosis form three distinct behavioural syndromes in dementia.

Aged↗
PubMed1996

Spectroscopic evidence for interstellar ices in comet Hyakutake.

Volatile compounds in comets are the most pristine materials surviving from the time of formation of the Solar System, and thus potentially provide information about conditions that prevailed in the primitive solar nebula. Moreover, comets may have supplied a substantial fraction of the volatiles on the terrestrial planets, perhaps including organic compounds that played a role in the origin of life on Earth. Here we report the detection of hydrogen isocyanide (HNC) in comet Hyakutake. The abundance of HNC relative to hydrogen cyanide (HCN) is very similar to that observed in quiescent interstellar molecular clouds, and quite different from the equilibrium ratio expected in the outermost solar nebula, where comets are thought to form. Such a departure from equilibrium has long been considered a hallmark of gas-phase chemical processing in the interstellar medium, suggesting that interstellar gases have been incorporated into the comet's nucleus, perhaps as ices frozen onto interstellar grains. If this interpretation is correct, our results should provide constraints on the temperature of the solar nebula, and the subsequent chemical processes that occurred in the region where comets formed.

Extraterrestrial Environment↗
PubMed1996

Behavioural problems in dementia and biochemistry: clinical aspects.

Behavioural and psychiatric problems in dementia are clinically important; they are also theoretically interesting. Neurochemical factors are likely to play a causal role in some of these problems. Two approaches to investigating the biochemical basis of behavioural problems are outlined: the correlation of prospectively collected behavioural data with postmortem neurochemical measures; and the detailed analysis of behaviour allowing investigation of underlying mechanisms. These approaches are illustrated with empirical data. David Bowen's neurochemical approach to dementia provided stimulus to this work.

Animals↗
PubMed1996

The effect of tourniquet use on postoperative strength recovery after arthroscopic meniscectomy.

The purpose of this prospective study was to determine the effect of pneumatic tourniquet use during arthroscopic meniscectomy on postoperative recovery of quadriceps and hamstring strength. Thirty-four patients with no ligamentous instability underwent arthroscopic meniscectomy after random assignment to the tourniquet or no tourniquet group. Tourniquet pressure was determined with a nomogram that considered thigh circumference and systolic blood pressure at time of induction. Quadriceps and hamstring strengths were tested preoperatively and at 1 week and 4 weeks postoperatively on a Biodex isokinetic dynamometer and expressed as a percentage of the uninvolved side. No significant differences in quadriceps or hamstring strength were noted between groups at any time periods. The findings of this study indicate that recovery of quadriceps and hamstring strength after arthroscopic meniscectomy is not adversely affected by tourniquet use if tourniquet times and pressures are carefully controlled.

Adolescent↗
PubMed1995

HCl absorption toward Sagittarius B2.

We have detected the 626 GHz J = 1 --> 0 transition of hydrogen chloride (H35Cl) in absorption against the dust continuum emission of the molecular cloud Sagittarius B2. The observed line shape is consistent with the blending of the three hyperfine components of this transition by the velocity profile of Sgr B2 observed in other species. The apparent optical depth of the line is tau approximately 1, and the minimum HCl column density is 1.6 x 10(14) cm-2. A detailed radiative transfer model was constructed which includes collisional and radiative excitation, absorption and emission by dust, and the radial variation of temperature and density. Good agreement between the model and the data is obtained for HCl/H2 approximately 1.1 x 10(-9). Comparison of this result to chemical models indicates that the depletion factor of gas-phase chlorine is between 50-180 in the molecular envelope surrounding the SgrB2(N) and (M) dust cores.

Astronomical Phenomena↗
PubMed1993

Evaluation of syringe-exchange for HIV prevention among injecting drug users in rural and urban areas of Wales.

This paper considers the prevention of HIV in rural and urban areas among both opiate and non-opiate drug injectors. A 2-year study evaluated specialist and community based syringe-exchange provision in Wales. Numbers of clients and patterns of attendance at eight syringe-exchange schemes were monitored together with comparative cross-sectional studies of attenders (n = 152) and non-attenders (n = 176) from the population of drug injectors in 1990 and 1991. A total of 1171 clients made 7553 visits in the 2-year period, 110,000 syringes were issued and 80% of needles and syringes were returned. There were few demographic differences between attenders and non-attenders, but large and significant differences in HIV risk behaviour; only 9% of attenders had recently shared syringes in 1990 (10% in 1991) compared to 41% of non-attenders (39% in 1991). The catchment areas of specialised services were limited (5 miles or less) and insufficient in rural areas. Alternative community approaches to syringe distribution and exchange are examined.

Cross-Sectional Studies↗
PubMed1993

Effect of outer membrane of Treponema denticola on bone resorption.

The effect of the outer membrane (outer sheath) of Treponema denticola on bone resorption was studied. Bone resorption was measured by the release of previously incorporated 45Ca from the shafts of the radii and ulnae of 19-day fetal rats. A treated-over-control ratio (T/C ratio) significantly greater than 1 indicated the stimulation of bone resorption by the test substance. The addition of outer membrane of T. denticola increased the release of 45Ca from the assay bones. The minimum concentrations required to yield significant 45Ca release from the assay bones were 15, 22 and 75 micrograms protein/ml for serovars a, b and c, respectively. These protein values corresponded to estimated lipopolysaccharide contents of 0.6, 0.8 and 2.8 micrograms/ml, based on 3-deoxy-2-manno-octulosonate analysis. Heat treatment of outer membrane (60 degrees for 30 min) did not change the effect on 45Ca release. Parathyroid hormone or prostaglandin E2, known to act synergistically with lipopolysaccharides in bone resorption, was also added to the assay system. Neither prostaglandin E2 at 10(-7) M nor parathyroid hormone at 40 ng/ml, by itself, increased 45Ca release. However, in the presence of 10 micrograms protein/ml of outer membrane of serovar b at 120 h, the T/C ratio was increased to 1.31 +/- 0.07 and 1.58 +/- 0.118, respectively. These results suggest that a lipopolysaccharide-like material is present in the outer membrane of T. denticola that may be responsible for bone resorption in the in vitro system.

Animals↗
PubMed1993

Fatty acid profiles of the outer membrane of ATCC strains 35405, 35404 and 33521 of Treponema denticola.

The fatty acid composition of the outer membrane (outer sheath) of Treponema denticola is not known. This study examined the fatty acid profiles of the outer membranes of T. denticola ATCC strains 35405, 35404, 33521. Homogeneous outer membranes were prepared from the three strains of T. denticola. The fatty acids were extracted and converted to methyl esters, and their mass spectra were determined with a sensitive Hewlett-Packard 5880A-5970 gas chromatography-mass spectrometry system. Fatty acids were identified by comparing the unknown fatty acid mass spectra to computer stored known mass spectra standards. Dodecanoic, 2 hydroxy dodecanoic, tridecanoic, tetradecanoic, pentadecanoic, hexadecanoic, 2-hydroxy hexadecanoic and octadecanoic acid were found in the assay spirochetes yielding correlation indices (r) of 0.8-1.00. Isotetradecanoic acid was found in the outer membranes of strains 33521 and 35405 (r = 0.913-0.967). Anteiso pentadecanoic and heptadecanoic acids were found in the outer membrane of strains 33521 and 35404 (r = 0.941-0.996), while cis 9, 12 octadecadienoic was found only in the outer sheath of strain 35405 (r = 0.922-0.958). The average concentration of dodecanoic, tridecanoic, tetradecanoic, pentadecanoic, hexadecanoic, heptadecanoic and octadecanoic acid in the outer membranes of strains 35405, 35404 and 33521 were as follows. Strain 35404: 138, 178, 845, 296, 751, not detected, and 699 nanogram per mg dry weight of the outer membrane. Strain 35404: 96, 125, 670, 306, 597, 38 and 249 nanograms per mg dry weight of the outer membrane. Strain 33521: 323, 135, 1650, 125, 9080, 235 and 618 nanograms per mg dry weight of the outer membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, Gas↗