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Biomedical subjects

P Griffiths

Publications and source records attributed to P Griffiths.

At least 73 records · Page 4Linked to original sources
PubMed1997

How constant is an individual's route of heroin administration? Data from treatment and non-treatment samples.

Three routes of heroin use were identified--injecting, 'chasing the dragon' and snorting. Whilst injecting and 'chasing the dragon' accounted for virtually all current heroin use, snorting had been the first route of use for nearly a fifth of heroin users in both the treatment and community samples. Overlap of lifetime experience of the different routes was widespread, with the majority of heroin users in both the treatment and community samples having used heroin by more than one route. Although less than half of the treatment sample had used heroin by injection on the first occasion, more than 90% had injected at least once, and over 80% had at some time used by 'chasing the dragon'. Only a quarter of the community sample had first used heroin by injecting, and yet, by the time of interview, two-thirds of the sample had injected. The majority of durable changes in route of heroin use were towards injecting and 'chasing the dragon', with transitions to snorting being extremely rare. For both the samples, transitions to injecting were twice as frequent as transitions to 'chasing'. Snorting appeared to be an unstable route of use, with almost all who initially snorted their heroin now using by injecting or 'chasing the dragon'.

Administration, Inhalation↗
PubMed1997

Adverse effects of stimulant drugs in a community sample of drug users.

A sample of drug users (n = 158) were contacted and interviewed in non-clinical community settings about their use of Ecstasy, cocaine powder, and amphetamines and the adverse effects of these drugs. Subjects reported a wide range of adverse effects including anxiety problems, depression, mood swings, feelings of paranoia, and panic attacks. Sleep and appetite disturbances were the most commonly reported problems. About half of all subjects reported depression and paranoid feelings associated with their stimulant use. Many of those reporting problems stated that these were mild. However, for all drugs, a substantial minority of users reported adverse effects which they rated as 'severe'. Between 30 and 55% of the sample reported having had at least one 'severe' adverse effect (30% cocaine, 35% Ecstasy and 55% amphetamine). There were clear differences between the different drugs in the likelihood and reported severity of adverse effects. Amphetamine use was associated with significantly more adverse effects and with more severe adverse effects than Ecstasy or cocaine. Cocaine powder was associated with the least severe adverse effects. A common pattern of drug use involved the use of depressant drugs such as opiates and benzodiazepines in addition to stimulants. The stimulant and depressant users were more likely than the stimulants-only users to use stimulants by injection and more likely to report adverse effects associated with stimulant use. The stimulant and depressant users were also more likely to have been treated for a drug problem. Approximately a quarter of the sample stated that they had stopped using stimulants up to the point of interview as a result of their bad experiences.

Adolescent↗
PubMed1997

Heroin smoking by 'chasing the dragon': origins and history.

The history of heroin smoking and the subsequent development and spread of 'chasing the dragon' are examined. The first heroin smoking originated in Shanghai in the 1920s and involved use of porcelain bowls and bamboo tubes, thereafter spreading across much of Eastern Asia and to the United States over the next decade. 'Chasing the dragon' was a later refinement of this form of heroin smoking, originating in or near Hong Kong in the 1950s, and refers to the ingestion of heroin by inhaling the vapours which result when the drug is heated-typically on tin-foil above a flame. Subsequent spread of 'chasing the dragon' included spread to other parts of South East Asia during the 1960s and 1970s, to some parts of Europe during the late 1970s and early 1980s, and to much of the Indian sub-continent during the 1980s. At the time of writing, 'chasing the dragon' has now been reliably reported from many parts of the world but not from others with an established heroin problem-such as the United States and Australia. The significance of this new form of heroin use is examined, including consideration of the role of the different effect with this new form of use, the different types of heroin, and changing public attitudes to injecting.

Administration, Inhalation↗
PubMed1997

Heroin in the United Kingdom: different forms, different origins, and the relationship to different routes of administration.

Heroin exists in the United Kingdom in several different forms, which vary not only in their country of origin and purity, but also in their suitability for use by either injecting or by 'chasing the dragon'. The availability of these different forms of heroin has varied considerably over time. A review of the characteristics and availability of these various forms of heroin in recent years is presented, accompanied by consideration of their probable intended use by injection or by 'chasing the dragon'. Samples of black market heroin in the salt form are usually used by injection, whereas the base form is usually taken by 'chasing the dragon'. The heroin yield to the drug user from samples of heroin taken by 'chasing the dragon' varies according to its base or salt format and according to the presence of other drugs in the sample. Heroin samples from different countries of production mostly conform to either base or salt form. Novel approaches at the macro level to prevention and control of heroin-related problems through influence upon this complex heroin market-place should now be considered.

Journal Article↗
PubMed1997

Executive function and psychosocial adjustment in children with early treated phenylketonuria: correlation with historical and concurrent phenylalanine levels.

The issue of what level of phenylalanine (phe) constitutes a safe upper limit for the therapeutic range in dietary treatment of phenylketonuria (PKU) remains unsettled. It has been proposed that the previous guideline figure of 600 mumol l-1 may result in specific impairment of executive functions such as attention, planning and set maintenance. The executive dysfunction theory was investigated by correlation historical and concurrent phe with executive, non-executive and personality tests in a group of early and continuously treated children, aged 10-13 years, with classical PKU, whose average phe levels of 355 mumol l-1 (SD = +/-144) for the pre-school period and 480 mumol l-1 (SD +/-193) for the primary school period corresponded to the upper limits presently recommended in the UK of 360 and 480 mumol l-1 for these age ranges. No clear associations were found between historical or concurrent phe levels and any of the neuropsychological or personality measures, thereby weakening the case for the emergence of executive deficits, at least when average phe levels remain close to the upper limits now considered safe. Furthermore no significant differences were found on psychological variables where comparison with population norms was possible.

Adjustment Disorders↗
PubMed1997

Internal and external carotid contributions to near-infrared spectroscopy during carotid endarterectomy.

BACKGROUND AND PURPOSE: The internal carotid (ICA) and external carotid (ECA) contributions to changing concentrations of oxyhemoglobin (Hbo2) and deoxyhemoglobin (Hb) during carotid endarterectomy were assessed with the use of near-infrared spectroscopy (NIRS). METHODS: NIRS optodes were placed on the forehead with an interoptode distance of 6 cm, and laser-Doppler flowmetry (LDF) was used to monitor the change in skin blood flow between the optodes. Hb, Hbo2, LDF, arterial blood pressure, and middle cerebral artery flow velocity were recorded continuously. The ECA was clamped 2 minutes before the ICA was clamped. Suitable multimodal recordings were achieved in 44 patients. RESULTS: When the ECA was clamped, 76% of patients showed a fall in Hbo2 and 65% an increase in Hb. When corrected for changes in arterial blood pressure, an accompanying fall in cutaneous LDF predicted the fall in Hbo2 with high sensitivity (100%) and specificity (100%). Among those with no NIRS changes during ECA clamping, 56% had severe ECA stenosis or occlusion; none of these showed an accompanying fall in LDF. In contrast, when the ICA was clamped, substantial additional changes in NIRS occurred in 55% of cases, all of which were associated with a fall in flow velocity, but none with a change in LDF. Patients with a constant flow velocity after ICA clamping also showed no change in NIRS. CONCLUSIONS: Both the ECA and ICA vascular territories contribute to NIRS changes during carotid endarterectomy. The external carotid contribution to NIRS can be monitored with cutaneous LDF.

Aged↗
PubMed1997

A transcultural pattern of drug use: qat (khat) in the UK.

BACKGROUND: This study investigates patterns of qat use among 207 Somalis living in London. METHOD: Subjects were recruited using privileged access interviewing. Somalian interviewers were recruited who shared the same culture as the subjects. Data were collected by means of a structured interview. RESULTS: One hundred and sixty-two subjects (78%) had used qat. The majority (76%) used more qat than in Somalia. Some users reported moderate dependence; a minority reported severe problems. Adverse psychological effects included sleep problems, anxiety and depression. Medical problems associated with qat use were rare. CONCLUSIONS: Qat users who continue to use this drug when it is transplanted from a traditional context may experience difficulties. Qat use can also be seen as playing a positive role in supporting the cultural identity of the Somalian community. Severe problems were rarely reported. Qat consumption should be considered when addressing health-related topics with patients from those communities in which qat use is common.

Adolescent↗
PubMed1997

Transitory hyperphenylalaninaemia in children with continuously treated phenylketonuria.

Cognitive and behavioral effects of temporarily challenging the CNS with elevated levels of phenylalanine in treated phenylketonuria (PKU) were investigated in a triple-blind, cross-over study. A high phenylalanine supplement was given over 3 months to sixteen 10- to 16-year-old early and continuously treated children with classical PKU. We used the WISC and Rivermead tests to measure cognitive function and the Rutter Scales to assess disordered behavior. Parents and children guessed at the condition imposed. The Group x Phase interaction for phenylalanine level was statistically significant, but this pattern was not mirrored in the psychological test data, and guessing was random. Results suggest that intellectual ability, memory, and conduct are not affected by medium-term hyperphenylalaninaemia in PKU after 10 or more years of treatment.

Adolescent↗
PubMed1997

HIV-1 dynamics after transient antiretroviral therapy: implications for pathogenesis and clinical management.

Simple models of CD4 lymphocyte interactions with human immunodeficiency virus (HIV) lead to the hypothesis that progression of HIV infection involves an increase in viral replicative capacity, due either to changes in the virus or in the host environment, or both. In order to consider how changes in plasma virus load after transient, potent antiretroviral therapy can be used to test the above hypothesis--a simple mathematical model that encompasses the processes of (1) arrival of new CD4 lymphocytes, (2) death/removal of these cells by HIV-independent mechanisms, (3) infection of susceptible CD4 lymphocytes by HIV, and (4) death/removal of infected cells was investigated. This showed that the in vivo rate of increase in plasma virus load immediately after transient therapy provides a measure of the viral replicative capacity. Thus, the hypothesis that progression of HIV infection involves an increase in viral replicative capacity can be tested by measuring this viral growth rate in patients with high CD4 counts and in patients with low CD4 counts. Studies should thus investigate dynamics of changes in virus levels after stopping antiretroviral therapy and, in particular, measure rates of increase in virus in patients at high and low CD4 counts. In practice, such data may assist in therapeutic management of patients with HIV infection.

Anti-HIV Agents↗
PubMed1996

Editorial.

Explore the source record for details and available documents.

Journal Article↗
PubMed1996

Deficiency of complex II of the mitochondrial respiratory chain in late-onset optic atrophy and ataxia.

Defects of the mitochondrial respiratory chain are increasingly being recognized as an important cause of neurological disease in humans. In many of these patients, the biochemical defect results from an abnormality of the mitochondrial genome. Respiratory chain defects involving complex II, which is entirely encoded by the nuclear genome, are comparatively rare. We report the clinical and biochemical findings in 2 elderly sisters who presented with late-onset neurodegenerative disease. In both patients, a partial deficiency of complex II (approximately 50% of control values) was shown to be present in mitochondria from muscle and platelets. The enzyme defect was not expressed in cultured skin fibroblasts or immortalized lymphocytes. There was an overexpression of the 70-kd flavoprotein subunit in muscle mitochondria from both patients, although we showed that this subunit is present in normal amounts in mitochondrial membranes. Our studies highlight the diversity of the clinical presentation of respiratory chain disease and that complex II deficiency should enter the differential diagnosis of certain patients with late-onset neurodegenerative disease.

Ataxia↗
PubMed1996

Femoral articular shape and geometry. A three-dimensional computerized analysis of the knee.

An average, three-dimensional anatomic shape and geometry of the distal femur were generated from x-ray computed tomography data of five fresh asymptomatic cadaver knees using AutoCAD (AutoDesk, Sausalito, CA), a computer-aided design and drafting software. Each femur model was graphically repositioned to a standardized orientation using a series of alignment templates and scaled to a nominal size of 85 mm in mediolateral and 73 mm in anteroposterior dimensions. An average generic shape of the distal femur was synthesized by combining these pseudosolid models and reslicing the composite structure at different elevations using clipping and smoothing techniques in interactive computer graphics. The resulting distal femoral geometry was imported into a computer-aided manufacturing system, and anatomic prototypes of the distal femur were produced. Quantitative geometric analyses of the generic femur in the coronal and transverse planes revealed definite condylar camber (3 degrees-6 degrees) and toe-in (8 degrees-10 degrees) with an oblique patellofemoral groove (15 degrees) with respect to the mechanical axis of the femur. In the sagittal plane, each condyle could be approximated by three concatenated circular arcs (anterior, distal, and posterior) with slope continuity and a single arc for the patellofemoral groove. The results of this study may have important implications in future femoral prosthesis design and clinical applications.

Aged↗
PubMed1996

Reflexology.

Reflexology is potentially a very valuable therapeutic nursing skill and could have wide-ranging and cost-effective benefits in health care, from special care baby units through to care of the elderly. Like many other complementary therapies, reflexology seems to restore and maintain health by rebalancing the body. Whilst to many, reflexology may appear a gentle therapy, it is vital that the contraindications are known and that it is only carried out by trained therapists.

Holistic Nursing↗