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Biomedical subjects

H Johnstone

Publications and source records attributed to H Johnstone.

11 recordsLinked to original sources
PubMed2006

Hypercalcaemia in relapsed medulloblastoma 8 years post-diagnosis; evidence to support PTHrP production by medulloblastoma cells.

BACKGROUND: A 19-year-old male presented with symptomatic hypercalcaemia as the first manifestation of relapsed metastatic medulloblastoma. Management at the time of the initial presentation 8 years earlier was with surgical excision and craniospinal radiotherapy. His biochemistry at the time of relapse and studies of medulloblastoma cell lines provide an insight into the pathogenesis of his hypercalcaemia. METHODS: Parathyroid hormone-related protein (PTHrP) was measured by immunoradiometric assay in blood, and in conditioned and control media from three medulloblastoma cell lines following 72 h growth. RESULTS: The histology at initial presentation (11 years of age) and at the time of relapse (with bone marrow infiltration and widespread bony metastases) demonstrated medulloblastoma. Ionised calcium concentrations at relapse were 2.89 mmol/l and serum PTHrP levels were increased at the same time (2.7 pmol/l; normal range: 0.7-1.8 pmol/l). There was evidence of PTHrP production by one cell line (MHH-MED-8A) while results for both other lines tested were below the limit of detection. CONCLUSIONS: Relapse 8 years after diagnosis is unusual in medulloblastoma and for this relapse to manifest as hypercalcaemia is also very uncommon. Our investigations suggest that the clinical picture was a reflection of PTHrP production by medulloblastoma cells.

Adolescent↗
PubMed2006

The role of the nurse practitioner in psychiatric/mental health nursing: exploring consumer satisfaction.

There is a substantial body of literature pertaining to the role of the nurse practitioner. Research directed towards consumer satisfaction suggests that the care provided by nurse practitioners is perceived as at least equal to that provided by a medical practitioner. However, there is a paucity of literature examining the nurse practitioner role in the psychiatric/mental health field. An evaluation of a Nurse Practitioner demonstration model has recently been undertaken in the Crisis, Assessment and Treatment Team in Victoria, Australia. This article presents the findings of a qualitative, exploratory study. Individual interviews were conducted with consumers (n = 7) who had received care and treatment provided by the nurse practitioner candidate. Data analysis revealed two main themes: the quality of the service provided, and the unique role of the nurse. The findings supported the available literature in articulating the specific aspects of the nurse practitioner role that are favourably perceived by consumers of services. This study contributes to the limited body of knowledge in the psychiatric/mental health nursing field and specifically emphasizes the importance of the relationship between nurse practitioner and consumer in facilitating the provision of effective care and treatment.

Communication↗
PubMed2004

Investigating the limits of filopodial sensing: a brief report using SEM to image the interaction between 10 nm high nano-topography and fibroblast filopodia.

Having the ability to control cell behaviour would be of great advantage in tissue engineering. One method of gaining control over cell adhesion, proliferation, guidance and differentiation is use of topography. Whilst it has be known for some time that cells can be guided by micro-topography, it is only recently becoming clear that cells will respond strongly to nano-scale topography. The fact that cells will take cues from their micro- and nano-environment suggests that the cells are in some way 'spatially aware'. It is likely that cells probe the shape of their surroundings using filopodia, and that this initial filopodia/topography interaction may be critical to down-stream cell reactions to biomaterials, or indeed, the extracellular matrix. One intriguing question is how small a feature can cells sense? In order to investigate the limits of cell sensing, high-resolution scanning electron microscopy has been used to simultaneously view cell filopodia and 10 nm high nano-islands. Fluorescence microscopy has also been used to look at adhesion formation. The results showed distinct filopodial/nano-island interaction and changes in adhesion morphology.

Cell Adhesion↗
PubMed2004

Abnormal cognitive function in treated congenital hypopituitarism.

AIMS: To assess cognitive function in school age children with congenital pituitary hormone deficiency (PHD). METHODS: Ten children with PHD (aged 6.0-15.6 years, mean 11.5 years) and sibling controls (aged 8.7-14.9 years, mean 12.1 years) were assessed using the Wechsler Intelligence Scale for Children (WISC-III UK). RESULTS: The patients' full scale IQ scores were all below average (mean 75, 95% CI 70-80), but were not significantly different to those of sibling controls (mean 82, 95% CI 75-89). There was no difference in verbal IQ between patients and siblings, but performance IQ was significantly reduced (mean 75, 95% CI 68-82 in patients; mean 88, 95% CI 80-96 in sibling controls). The reduced performance IQ reflected a poorer performance in tasks assessing perceptual organisational skills. CONCLUSIONS: Data suggest that children with PHD have an IQ that is below average when compared to the population norm and a reduced performance IQ when compared to sibling controls. This may reflect abnormal brain development or could be linked to the impact of hypoglycaemia or low thyroxine concentrations in early life. This information is of value when counselling parents and planning a child's care and education, although further, more extensive studies of patients and siblings are required.

Adolescent↗
PubMed2003

Endothelization and adherence of leucocytes to nanostructured surfaces.

We analyse the leucocyte and endothelial cell response to polybromostyrene-polystyrene (PS/PBrS) and the poly-n-butylmethacrylate-polystyrene (PnBMA/PS) systems, both in flat form or nanostructured surfaces consisting of nanohills with increasing hill height (13-95nm). Experiments were carried out first with blood leucocytes alone, endothelial cells (of three different types) alone, and finally, using blood cells and endothelized nanosurfaces. Blocking monoclonal antibodies specific for CD11, CD29, CD31, CD54, CD166 were used to analyse whether and to what extent adhesion molecules could be involved in the adherence of both blood leucocytes and endothelial cells to different nanosurfaces. Expression of CD29 (beta-1 integrin), CD54 (ICAM-1) and CD166 (ALCAM) on blood leucocytes was dependent on the hill height, being most prominent with 13nm (PS/PBrS) and 45nm hill (PnBMA/PS) nanosurfaces. Adherence of a human microvascular endothelial cell line and umbilical primary endothelial cells was also related to hill height, being most prominent with 13nm hill height. An indirect correlation was observed between the extent of endothelization and the degree of leucocyte adherence. In cases of low to medium extent of endothelization, the adherence of monocytes and granulocytes was mediated by the expression of CD166, CD29 and CD11a (alpha-L integrin), CD29, CD31 (PECAM-1), respectively. Scanning electron microscopy studies showed the predominant emission of pseudopodia at the holes of the surfaces and the focal contacts with the nanosurfaces. Our studies emphasize the relevance of testing functional properties in co-culture experiments in the development and optimization of nanosurfaces for biomedical application.

Cell Adhesion↗
PubMed2002

In vitro reaction of endothelial cells to polymer demixed nanotopography.

The introduction of topography to material surfaces has been shown to strongly affect cell behaviour, and the effects of micrometric surface morphologies have been extensively characterised. Research is now starting to investigate the reaction of cells to nanometric topography. This study used polymer demixing of polystyrene and poly(4-bromostyrene) producing nanometrically high islands, and observed endothelial cell response to the islands. Three island heights were investigated; these were 13, 35 and 95 nm. The cells were seen to be more spread on the manufactured topographies than that on flat surfaces of similar chemistry. Other morphological differences were also noted by histology, fluorescence and scanning electron microscopy, with many arcuate cells noted on the test surfaces, and cytoskeletal alignment along the arcuate features. Of the nanotopographies, the 13 nm islands were seen to give the largest response, with highly spread cell morphologies containing well-defined cytoskeleton.

Biocompatible Materials↗
PubMed2000

Sex-steroid induction of endogenous opioid inhibition on oxytocin secretory responses to stress.

In pregnancy, endogenous opioids inhibit enhanced basal and stressor-stimulated oxytocin neurone activity and secretion. By contrast, stress responses of the hypothalamo-pituitary-adrenal (HPA) axis are reduced in pregnancy. We investigated whether the high levels of oestradiol and progesterone of pregnancy could induce these changes. Silastic capsules containing oestradiol or progesterone (or control capsules) were implanted s.c. in virgin female rats for 16 or 17 days, with or without progesterone removal on day 15 to mimic the progesterone withdrawal seen at the end of pregnancy. Plasma concentrations of oxytocin, adrenocorticotrophic hormone (ACTH) and corticosterone were measured in jugular vein blood samples from conscious rats. Under basal conditions, naloxone (5 mg/kg) increased oxytocin secretion in all groups, but had no greater effect in sex-steroid treated rats, and did not induce Fos expression in the supraoptic nucleus. Forced swimming, a stressor, increased oxytocin secretion at 5 min in vehicle-injected controls, and this response was slightly attenuated in the sex-steroid treated groups. Pretreatment with naloxone greatly enhanced the response in the sex-steroid treated rats, and was less effective in the controls. In rats treated with oestradiol alone, naloxone prolonged the response. Thus, the combined sex-steroid treatment enhanced the responsiveness of oxytocin neurones to the stressor, while simultaneously restraining oxytocin secretion via endogenous opioid inhibition. In the same rats, ACTH and corticosterone secretion was also stimulated by the stressor, but the hypothalamo-pituitary-adrenal (HPA) axis response was not attenuated in sex-steroid treated rats. Naloxone weakly reduced the HPA axis response in controls and was ineffective in the sex-steroid treated rats. We conclude that oestradiol and progesterone may be responsible for inducing the opioid restraint and enhanced oxytocin neurone responsiveness in pregnancy.

Animals↗
PubMed1994

An evaluation of the treatment effectiveness of the Chicago Health Outreach Acupuncture Clinic.

Acupuncture is a treatment modality that is particularly applicable for homeless clients because of its low cost and portability as well as because of its effectiveness in treating the symptomatology of pain syndromes, substance abuse, and human immunodeficiency virus infection. A two-part descriptive study was conducted to determine the response to acupuncture of homeless persons at the Chicago Health Outreach Clinic. Part 1 of the study consisted of a retrospective chart review of 45 patients to assess acupuncture treatment effectiveness. Part 2 of the study consisted of using a numerical rating scale report form to assess treatment effectiveness of 30 patients. Part 1 of the study indicated that 51% had a positive response to treatment, 42% were indeterminate or lacked documentation of response, and 7% had no response to treatment. Part 2 of the study demonstrated that 97% had a positive response to treatment, with 3% reporting no response to treatment. Acupuncture treatment did effectively decrease the symptomatology of the homeless clients seen in the Chicago Health Outreach Acupuncture Clinic. Further research should involve follow-up of these clients to assess the length of symptom relief to further determine long-range effectiveness and cost of treatment.

Acupuncture Analgesia↗
PubMed1976

Monozygotic twins discordant for urinary tract anomalies and presenting as hydramnios.

This report describes premature monozygotic twins, 1 of whom had an unusual clinical manifestation of a rare congenital anomaly, the other being normally developed. Hydramnios had been suspected during pregnancy and, because of the severity, amniocentesis was attempted. However, it became evident that the hugely distended abdomen did not indicate hydramnios, the pregnancy actually being complicated by oligohydramnios. Pulmonary hypoplasia was the cause of the immediate neonatal demise of 1 twin; the other expired after prolonged therapy for meconium aspiration. No similar cases have been reported in the literature which is reviewed briefly. Particular attention is given to discordant anomalies in monozygotic twins, the mode of their placentation, and the development of amnion nodosum.

Abnormalities, Multiple↗
PubMedDate not supplied

Incidence of sexually transmitted diseases and Pap smear results in female homeless clients from the Chicago Health Outreach Project.

Homeless persons have difficulty gaining access to health care. In 1985 the Chicago Health Outreach Project was created to improve their access to health care. Staff and client reviews indicated that female homeless clients required increased outreach efforts. Consequently, a mobile women's health unit was developed in 1990. Review of 128 records of 104 female homeless clients indicated that 30% of Pap smears done were abnormal, with atypia (14%) and inflammation (10%) the most common findings. The incidence of chlamydia, gonorrhea, and trichomoniasis was 3%, 6%, and 26%, respectively. There was a significant association between the presence of trichomoniasis and an abnormal Pap smear. These results emphasize the importance of providing regular gynecological care to homeless women. Research is needed on the implications of abnormal Pap smears and sexually transmitted diseases for this population of female homeless clients.

Adolescent↗