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Biomedical subjects

S Henderson

Publications and source records attributed to S Henderson.

At least 19 recordsLinked to original sources
PubMed1992

Reaction time and movement time in children with a Developmental Coordination Disorder.

The Test of Motor Impairment (TOMI) was used to select 12 children with a Developmental Coordination Disorder (DCD) and 12 age-matched controls. In an aiming task, movement latency, movement duration and its variability were significantly prolonged in the DCD group. In a coincidence timing version of the task, absolute timing error was significantly greater in the DCD group. The most robust chronometric effect for differentiating the two groups seemed to be the duration of movement when the target was small. Multiple regression showed that TOMI was a powerful indicator of movement duration.

Child↗
PubMed1992

The Epstein-Barr virus (EBV) nuclear antigen 1 BamHI F promoter is activated on entry of EBV-transformed B cells into the lytic cycle.

In Epstein-Barr virus (EBV)-positive Burkitt's lymphoma cell lines exhibiting the latency I form of infection (i.e., EBV nuclear antigen 1 [EBNA1] positive in the absence of other latent proteins), the EBNA1 mRNA has a unique BamHI Q/U/K splice structure and is expressed from a novel promoter, Fp, located near the BamHI FQ boundary. This contrasts with the situation in EBV-transformed lymphoblastoid cell lines (LCLs) exhibiting the latency III form of infection (i.e., positive for all latent proteins), in which transcription from the upstream Cp or Wp promoters is the principal source of EBNA mRNAs. We carried out cDNA amplifications with oligonucleotide primer-probe combinations to determine whether Fp is ever active in an LCL environment. The results clearly showed that some LCLs express a Q/U/K-spliced EBNA1 mRNA in addition to the expected Cp/Wp-initiated transcripts; this seemed inconsistent with the concept of Cp/Wp and Fp as mutually exclusive promoters. Here we show that Fp is indeed silent in latency III cells but is activated at an early stage following the switch from latency III into the virus lytic cycle. Four pieces of evidence support this conclusion: (i) examples of coincident Cp/Wp and Fp usage in LCLs are restricted to those lines in which a small subpopulation of cells have spontaneously entered the lytic cycle; (ii) transcripts initiating from Fp can readily be demonstrated in spontaneously productive lines by S1 nuclease protection; (iii) the presence of Fp-initiated transcripts is not affected by acyclovir blockade of the late lytic cycle; and (iv) infection of latently infected LCLs with a recombinant vaccinia virus encoding the EBV immediate-early protein BZLF1, a transcriptional transactivator which normally initiates the lytic cycle, results in the appearance of the diagnostic Q/U/K-spliced transcripts.

Antigens, Viral↗
PubMed1992

General practitioners' reported knowledge about depression and dementia in elderly patients.

Previous studies have shown that general practitioners often fail to detect dementia and depression in their elderly patients. The present study aimed to find out how much knowledge general practitioners have of these disorders. The knowledge of 36 general practitioners was assessed and it was found that they had a limited knowledge of the symptoms and signs of dementia and depression. Furthermore, almost 60% of the general practitioners did not know that Alzheimer's disease is the most common dementing disorder.

Aged↗
PubMed1991

Induction of bcl-2 expression by Epstein-Barr virus latent membrane protein 1 protects infected B cells from programmed cell death.

Epstein-Barr virus (EBV) not only induces growth transformation in human B lymphocytes, but has more recently been shown to enhance B cell survival under suboptimal conditions where growth is inhibited; both effects are mediated through the coordinate action of eight virus-coded latent proteins. The effect upon cell survival is best recognized in EBV-positive Burkitt's lymphoma cell lines where activation of full virus latent gene expression protects the cells from programmed cell death (apoptosis). Here we show by DNA transfection into human B cells that protection from apoptosis is conferred through expression of a single EBV latent protein, the latent membrane protein LMP 1. Furthermore, we demonstrate that LMP 1 mediates this effect by up-regulating expression of the cellular oncogene bcl-2. The interplay between EBV infection and expression of this cellular oncogene has important implications for virus persistence and for the pathogenesis of virus-associated malignant disease.

Antigens, Viral↗
PubMed1991

Activation of Epstein-Barr virus latent genes protects human B cells from death by apoptosis.

Epstein-Barr virus (EBV), a human herpesvirus, establishes a persistent asymptomatic infection of the circulating B-lymphocyte pool. The mechanism of virus persistence is not understood but, given the limited lifespan of most B cells in vivo, it seems most likely that EBV-infected cells must gain access to the long-lived memory B-cell pool. Here we show in an in vitro system that EBV, through expression of the full set of eight virus-coded 'latent' proteins, can protect human B cells from programmed cell death (apoptosis), the deletion mechanism which normally restricts entry into memory. We have found that EBV-positive Burkitt's lymphoma (BL) cell clones retaining the original tumour cell phenotype and expressing only one of the virus latent proteins, the nuclear antigen EBNA 1, are extremely sensitive to apoptosis; in this respect they resemble the tumour's normal cell of origin found in the germinal centres of lymphoid tissue. By contrast, isogenic BL cell clones which have activated expression of all eight EBV latent proteins are resistant to the induction of apoptosis. The EBV latent proteins should therefore be seen not just as activators of B-cell proliferation but, perhaps more importantly, as mediators of enhanced B-cell survival.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1991

Epstein-Barr virus (EBV)-associated lymphoproliferative disease in the SCID mouse model: implications for the pathogenesis of EBV-positive lymphomas in man.

When human peripheral blood lymphocytes (PBLs) from Epstein-Barr virus (EBV)-seropositive donors are injected intraperitoneally into SCID mice, EBV+ B cell tumors develop within weeks. A preliminary report (Mosier, D. E., R. J. Gulizia, S. M. Baird, D. D. Richman, D. B. Wilson, R. I. Fox, and T. J. Kipps, 1989. Blood. 74(Suppl. 1):52a) has suggested that such tumors resemble the EBV-positive malignancy, Burkitt's lymphoma. The present work shows that generally the human (hu) PBL-SCID tumors are distinct from Burkitt's lymphoma and instead resemble lymphoblastoid cell lines (LCLs) generated by EBV-infection of normal B cells in vitro in terms of: (a) their cell surface phenotype, with expression of B cell activation antigens and adhesion molecules, (b) normal karyotype, and (c) viral phenotype, with expression of all the transformation-associated EBV latent proteins and, in a minority of cells, productive cycle antigens. Indeed, in vitro-transformed LCLs also grow when inoculated into SCID mice, the frequency of tumor outgrowth correlating with the in vitro growth phenotype of the LCL which is itself determined by the identity of the transforming virus (i.e., type 1 or type 2 EBV). Histologically the PBL-derived hu-SCID tumors resemble the EBV+ large cell lymphomas that develop in immuno-suppressed patients and, like the human tumors, often present at multiple sites as individual monoclonal or oligoclonal foci. The remarkable efficiency of tumor development in the hu-SCID model suggests that lymphomagenesis involves direct outgrowth of EBV-transformed B cells without requirement for secondary genetic changes, and that selection on the basis of cell growth rate alone is sufficient to explain the monoclonal/oligoclonal nature of tumor foci. EBV+ large cell lymphoma of the immunosuppressed may arise in a similar way.

Animals↗
PubMed1991

The effects of ingesting polylactate or glucose polymer drinks during prolonged exercise.

Five trained, fasted male cyclists rode a cycle ergometer three times at 50% of VO2max for 180 min. Using a balanced order, double-blind procedure, subjects were given either a solution containing polylactate (PL: 80% polylactate, 20% sodium lactate, in 7% solution with water), glucose polymer (GP: multidextrin in 7% solution with water), or control (C: water sweetened with aspartame) 5 min before exercise and at 20-min intervals during exercise. Venous blood samples were taken at rest and at 20-min intervals during exercise. In general, PL and GP rendered similar results except that pH and bicarbonate (HCO3-) were higher in PL. There were no differences between treatments in perceived exertion, sodium, potassium, chloride, lactate, heart rate, oxygen consumption, rectal temperature, or selected skin temperatures. These data show that polylactate may help maintain blood glucose and enhance blood buffering capacity during prolonged exercise and could be a useful component in an athletic fluid replacement beverage.

Adult↗
PubMed1990

The effects of shear stress on endothelial cell retention and function on expanded polytetrafluoroethylene.

We evaluated the adherence of indium 111-radiolabeled endothelial cells to fibronectin-treated expanded polytetrafluoroethylene surfaces exposed to high (437 s-1) vs low (218 s-1) shear and the influence of shear on prostacyclin production. Canine jugular vein factor VIII-positive endothelial cells in passages 3 through 6 were incubated with 111Indium-oxine, and labeled cells were seeded onto fibronectin-treated expanded polytetrafluoroethylene patches. Patches with confluent cells were exposed to shear in a Weissenberg rheogoniometer for intervals ranging up to 60 minutes. Percent endothelial cell retention was determined by gamma counting of patches and media and by histologic evaluation. Prostacyclin production (tritiated radioimmunoassay of 6-keto-prostaglandin F1 alpha) was assayed on perfusing media. Results showed no differences in 6-keto-prostaglandin F1 alpha production between shear rates or time periods. Endothelial cell retention did not differ between the shear rates. Rotational shear caused persistent cell loss over time in either high- or low-shear conditions. This persistent cell loss in response to steady rotational shear differs from that in response to identical rates of pulsatile linear shear in our laboratory where cell loss approached zero after 15 minutes.

Animals↗
PubMed1979

Psychiatric disorder in Canberra. A standardised study of prevalence.

A standardised survey of prevalence has been carried out in a general population. The epidemiological method employed is innovative in its use of two established instruments, the GHQ and the PSE, harnessed together in a two-phase design. 756 persons were interviewed, giving a response rate of 85% in phase 1. 157 were then interviewed with the PSE in phase 2 within a few days, giving a response rate of 92% in this weighted subsample. The point prevalence of non-psychotic morbidity, based on the distribution of GHQ scores, is higher than elsewhere in Australia, the excess being in Canberra males. The PSE data weighted back to represent the total population, show a distribution of morbidity in women which is remarkably similar to that in the very different population of Camberwell. The overall point prevalence of threshold and definite cases is 9.0% +/- 3.2. Case rates did not vary significantly with age or sex, but were higher in the separated, the single and the widowed. This study represents an advance in the reliable and economical detection of psychiatric morbidity at specified levels of severity in general populations.

Adolescent↗
PubMed1979

Types of attempted suicide (parasuicide).

The clinical usefulness of a typology of parasuicide, reported in a previous paper, has been improved. A finer grained classification, using six instead of only three clusters, has proved itself to be clinically highly realistic. By a new method of cluster analysis which examines 80 attributes in each of 350 patients, the following types of parasuicide emerge: (1) operant, not alienated; (2) repeaters; (3) depressed with high life endangerment; (4) operant and alienated; (5) wristcutters; (6) undifferentiated. This more detailed typology may offer some advantages for clinical management and research.

Humans↗
PubMed1979

Length of residence, life change and psychiatric morbidity in an Australian urban population.

A component of a large population study of a random sample of 750 Canberra residents is described, in which length of residence in Canberra is related to the quality and quantity of recent life experiences, and to indices of minor psychiatric morbidity (the General Health Questionnair and the Zung Depression Scale). Life event frequency, but neither measure of morbidity, distinguished between persons with different lengths of residence in Canberra. It can be suggested that a random sample, containing an under-representation of migrants and persons moving from rural to urban environments, in whom the transition in shifting place of residence would be expected to be greatest, is an inappropriate sample to test hypotheses concerning length of residence and psychiatric morbidity, Future studies should give due emphasis to the adequate inclusion of these groups of persons.

Australia↗
PubMed1979

Neurosis and social bonds in an urban population.

The hypothesis that a deficiency in social bonds is a significant causal factor in neurosis was examined in a sample of an urban population (N = 756). The General Health Questionnaire was used as a measure of morbidity while social bonds were measured by the Interview Schedule for Social Interaction. An association was found between neurosis and a deficiency, particularly a perceived deficiency, in social bonds. Attention is now being directed to the interpretation of this association and to establishing the direction of causality.

Adolescent↗
PubMed1978

Social bonds in the epidemiology of neurosis: a preliminary communication.

In a random sample of the general population (N = 142) a strong inverse relationship was found between social bonds and the presence of neurotic symptoms. This association was strongest in the case of close affectional ties. Together, measures of social bonds accounted for 47 per cent of the variance in neurotic symptoms. While there is likely to be contamination between the two sets of variables, and while the data do not indicate the direction of causality, these findings constitute an aetiological lead which should be pursued.

Humans↗
PubMed1977

Do support systems prevent psychiatric disorders?

"Support" is a concept which is widely used by clinicians and laymen. What it consists of, though, is quite unclear. The proposition is examined, that just as certain components of the psychosocial environment are noxious, so other parts may cushion or protect the individual against adversity. Such an hypothesis would go some way towards understanding the sex distribution of neurosis, the active ingredient in Caplan's "psychosocial supplies", the presence for most adults of a principal attachment figure, the cohesion of the social network and the affectional function of the medical consultation. The development of this concept provides a new dimension for research in social psychiatry.

Child Care↗
PubMed1977

Virus-like particles in winter vomiting disease.

In an outbreak of winter vomiting disease affecting both pupils and staff in a primary school, virus-like particles were found in 7 out of 8 faecal specimens examined by electron microscopy. The particles measured 26 nm in diameter and had a buoyant density of 1-38--1-40 g/cm3 in caesium chloride. They could not be cultured in tissue-culture or organ-culture. In immune electron microscopy tests the particles appeared to differ antigenically from the Norwalk and Hawaii agents. Two out of three patients examined more than one month after their illness were still excreting the particles.

Adult↗
PubMed1977

An assessment of hostility in a population of adolescents.

In the course of an epidemiological survey of adolescents, the Hostility and Direction of Hostility Questionnaire was administered to 6,709 persons aged 13 to 18 years, representing 89% of secondary school students in Hobart, Tasmania. Extrapunitiveness was found to decrease substantially between the ages of 15 and 17 years in both sexes. Intropunitiveness also decreased, although to a lesser extent. Girls were less extrapunitive and more intropunitive than boys over the whole age range. These findings are discussed in relation to their clinical relevance and to the understanding of psychiatric disorder in adolescents.

Acting Out↗
PubMed1977

Coping behaviour after shipwreck.

A description is given of the coping behaviour of seven men who survived a shipwreck and were not rescued until 13 days later. The principal behaviours shown by the men were attachment ideation, drive to survive, modelling, prayer and hope. Particular attention is paid to the first of these, and consideration given to its likely origins in behavioural evolution. It is proposed as a hitherto inadequately recognized coping behaviour. A follow-up examination 12 to 24 months later showed that five of the seven men available had developed substantial psychiatric disorder, while by contrast one was not only well but claimed to have been enriched by the experience. Exposure to extreme adversity or disaster may have long-term effects on mental health. Further longitudinal studies of disaster victims are necessary for the design of informed after-care.

Adaptation, Psychological↗