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Biomedical subjects

N Young

Publications and source records attributed to N Young.

At least 37 records · Page 2Linked to original sources

The pre-hospital experiences of Samoan families who have had a child admitted to hospital with pneumonia: a qualitative investigation.

AIMS: The aims of this investigation were to describe the pre-hospital experiences; health actions and attitudes towards health services of Samoan families who have had a child hospitalised with pneumonia. This information will inform policy makers, health professionals and the Samoan community in order for them to improve and create health care services that are appropriate for Samoan families. METHOD: Twelve Samoan families, each with a child admitted to the Starship Children's Hospital with pneumonia, were interviewed in an open-ended in-depth interview style. Interviews lasted thirty to forty-five minutes and were undertaken in the preferred language of the caregiver (English or Samoan). RESULTS: For most caregivers continuity of care in the community was poor. Reasons for this included structural and personal barriers to health care services and mistrust of doctors. Mistrust influenced caregivers to go elsewhere for care and therefore care became fragmented. The theory of delayed presentation was not supported. Caregivers were quick to act on symptoms and behaviours that they believed were different from normal and worse than non-urgent symptoms. Those who 'self-referred' to the hospital had in fact visited a doctor in the community at least once prior to admission. They had then made their own decision to present to the hospital. Reasons for self-referral included mistrust of health professionals in the community and structural and personal barriers to services. A break down in communication between caregivers and health professionals was an important personal barrier to services. Caregivers did not feel that pneumonia was an appropriate illness to be treated solely with traditional methods. Caregivers who consulted traditional practitioners had also consulted at least one doctor in the community. CONCLUSION: Although Pacific children are less likely than other children to present to the emergency department with the documentation from a general practitioner, in many cases they have been to see one. A lack of continuity of care was caused by a break down in communication between the caregiver and the health professional rather than there being an inability by caregivers to recognise the symptoms of pneumonia and therefore a delay in presentation. This breakdown in communication could be one explanation for the differences in illness severity and hospitalisation for pneumonia among children in different ethnic groups. Considering their reasons for doing so, caregivers who self-referred attended the emergency department appropriately. The use of traditional health methods did not impair access to Western medicine for these children with pneumonia.

Adolescent↗

Protease inhibitors stimulate hematopoiesis and decrease apoptosis and ICE expression in CD34(+) cells.

Highly active retroviral therapy has been associated with a decline in the frequency of cytopenia in patients with human immunodeficiency virus (HIV) infection. This may result from lower hematologic toxicity of newer antiviral drugs and their increased efficacy against HIV-1. Protease inhibitors, in addition to their effects on HIV replication, appear to affect various cellular functions. Recently, it was reported that ritonavir inhibited caspase-1 expression in normal CD4(+) cells. It was hypothesized that protease inhibitors may improve hematopoietic function owing to their direct effects on the bone marrow progenitor cells. When ritonavir was added to methylcellulose cultures of bone marrow cells from HIV-infected patients and normal controls, colony formation increased 2.4-fold (n = 5) in control cultures and 4-fold (n = 5) in cultures of cells from HIV-infected patients. In the presence of ritonavir, cultures of CD34(+) cells showed markedly decreased apoptosis in comparison with untreated cultures (45% decrease in apoptotic cell number; n = 6). A synthetic inhibitor of caspase 1 (Ac-Tyr-Val-Ala-Asp-aldehyde [single-letter amino acid codes]), which inhibits activation of several caspases including CPP32 and interleukin 1beta-converting enzyme (ICE or caspase 1), also decreased the rate of apoptosis and enhanced colony formation by progenitor cells derived from HIV-infected patients (3-fold; n = 5). In ritonavir-treated samples derived from HIV-infected individuals, the number of cells expressing ICE also decreased. In conclusion, HIV protease inhibitors may, by blocking the caspase-dependent apoptotic pathway, overcome inhibition of hematopoiesis seen in patients with HIV infection, an effect unrelated to their antiviral activity. (Blood. 2000;96:2735-2739)

Antiretroviral Therapy, Highly Active↗

A comparison of full-length glycoprotein 120 from incident HIV type 1 subtype E and B infections in Bangkok injecting drug users with prototype E and B strains that are components of a candidate vaccine.

Complete gp120 sequence information was obtained from eight persons with incident HIV-1 infections (four subtype E and four subtype B) who were part of a prospective injecting drug user (IDU) cohort in Bangkok, Thailand, during 1996-1998. The incident subtype E strains were similar to the prototype subtype E strain CM244 isolated in 1992 in northern Thailand. The incident subtype B strains displayed divergence, in both overall genetic distance and other significant gp120 characteristics, from the prototype North American subtype B strain HIV-MN. Recombinant gp120s derived from CM244 and HIV-MN strains are components of a vaccine that is undergoing phase III efficacy testing, begun in March 1999, among Bangkok area IDUs. The information presented here will be important in the evaluation of any breakthrough HIV-1 infections occurring among vaccinees during the vaccine trial and in ongoing vaccine development efforts in Thailand.

AIDS Vaccines↗

Early experience in the use of Levovist ultrasound contrast in the evaluation of liver masses.

The aim of the present paper was to assess the utility of Levovist in defining the pathology of liver masses. Levovist is a new ultrasound contrast agent consisting of galactose microparticles, air bubbles and palmitic acid. Prospective studies were performed in patients referred for further evaluation of known liver masses. Levovist was peripherally injected and colour Doppler ultrasound studies were performed. Findings were correlated with clinicopathology and three other imaging modalities: biphasic spiral CT, CT arterial portography and contrast MRI. Twenty-five patients were studied (15 male and 10 female) in the age range 25-74 years. Liver masses ranged from 0.5 to 7 cm in maximum diameter. Thirteen lesions were benign and 12 were malignant (four hepatomas (HCC) and eight metastases). Levovist enhancement occurred in 18 lesions. Of these, six were benign (four focal nodular hyperplasias (FNH) and two haemangiomas). All 12 malignant lesions demonstrated enhancement. The HCC showed a mosaic pattern of central and peripheral enhancement, and the FNH demonstrated a spoke-wheel pattern. It was not possible to distinguish between haemangiomas and malignant lesions. Non-enhancing lesions may well be benign, with all malignancies showing some enhancement. Characteristic enhancement patterns were found for HCC (mosaic) and FNH (spoke-wheel). It was not possible to distinguish between metastases and benign lesions (haemangiomas) when the pattern of enhancement was peripheral.

Adult↗

Disability evaluation in children with hemidecorticectomy: use of the activity scales for kids and the pediatric evaluation disability inventory.

The purpose of this study is to investigate the level of disability of children who are either candidates for or have undergone a hemidecorticectomy. The Activity Scales for Kids and the Pediatric Evaluation Disability Inventory were demonstrated to be useful measurement tools yielding comparative results between subgroups. Overall, children with congenital disease seemed less autonomous postoperatively than were preoperative patients or children with acquired disease. Age at surgery and the interval between seizure onset and surgery are potentially important predictors of disability. This could reflect the importance of timing of surgery, development, environment, and possibly brain plasticity processes in this population.

Adolescent↗

Sequence variants of the axin gene in breast, colon, and other cancers: an analysis of mutations that interfere with GSK3 binding.

Axin is a recently discovered component of a multiprotein complex containing APC, beta-catenin, GSK3, and PP2A, which functions in the degradation of the beta-catenin protein. As part of WNT signal transduction, the function of the Axin complex is inhibited, leading to the accumulation of beta-catenin. The inappropriate stabilization of beta-catenin has been implicated in a range of human tumors. Two oncogenic mechanisms leading to beta-catenin stabilization are the loss of the APC tumor suppressor protein and the mutational activation of beta-catenin, such that the Axin/APC complex can no longer regulate it. Studies in Drosophila and mammalian tissue culture showed loss of Axin function interfered with beta-catenin turnover and activated beta-catenin/TCF-dependent transcription. Based on these observations, Axin was screened for mutations in a range of human tumor cell lines and primary breast tumor samples. We identified two sequence variants causing amino acid substitutions in four colon cancer cell lines, a Ser-to-Leu at residue 215 in LS513 and a Leu-to-Met at residue 396 in HCT-8, HCT-15, and DLD-1. The Axin L396M mutation was selected for further study since it lay within a region that was shown to interact with glycogen synthase kinase-3. Biochemical and functional studies showed that the L396M change interfered with Axin's ability to bind GSK3. Interestingly, this mutation and a neighboring L392M change differentially altered Axin's ability to interfere with two upstream activators of TCF-dependent transcription, Frat1 and Disheveled.

Amino Acid Sequence↗

Clinical disease associated with HIV-1 subtype B' and E infection among 2104 patients in Thailand.

BACKGROUND: Two HIV-1 envelope subtypes have accounted for virtually all infections in Thailand: subtype B' (Thai B), found mainly in injection drug users (IDU), and subtype E, found in over 90% of sexually infected persons and an increasing proportion of IDU in recent years. It remains unclear whether there are differences in pathogenesis associated with these HIV-1 subtypes. METHODS: From November 1993 to June 1996, demographic, risk, clinical, and laboratory data were collected by enhanced surveillance from HIV-infected inpatients (> or =14 years) at an infectious disease hospital near Bangkok. HIV-1 subtype was determined by V3-loop peptide enzyme immunoassay (EIA). Because of confounding, multivariate analyses were stratified by risk category and controlled for sex and age. RESULTS: The infecting HIV-1 subtype was determined for 2104 (94.9%) of 2217 HIV-infected patients with complete data: 284 (13.5%) were subtype B', 1820 (86.5%) were E. Specimens from 113 (5.1%) patients were non-reactive or dually reactive on peptide EIA and were excluded. Among IDU, 199 (67.2%) had subtype B', and 97 (32.7%) had E. IDU accounted for 70.1% (199/284) of patients with subtype B' and 5.3% (97/1820) of those with E. Patients infected with HIV-1 subtypes B' or E had similar spectrums of opportunistic infections (OI), levels of immunosuppression, and in-hospital mortality rates. Of patients who did not inject drugs, more patients infected with subtype E had extrapulmonary cryptococcosis than those with subtype B' (adjusted odds ratio, 2.6; 95% confidence interval, 1.28-5.37). CONCLUSION: HIV-1 subtypes B' and E seem to be associated with similar degrees of immunosuppression and, with one exception, with similar OI patterns. These data do not suggest an association between HIV-1 subtype and differences in pathogenicity.

Adolescent↗

Pitfalls in the use of spiral CT for identification of intracranial aneurysms.

We describe problems encountered in our first 136 patients, with 95 aneurysms, who underwent spiral CT for investigation of possible aneurysms involving the circle of Willis and adjacent major vessels, and who had surgical and/or angiographic confirmation. There were seven false-positive cases, of which the first three could be explained by operator inexperience. There were four false negatives, all small aneurysms; two were not seen because of operator error and two were hidden by an adjacent larger aneurysm. Clip artefacts prevented diagnostic studies in six of 21 postoperative studies. One aneurysm was outside the CT field of view, being on a pericallosal artery. One basilar artery tip aneurysm was excluded from the field of the CT study because of a planning error. Inspection of the axial source images is critical if the diagnosis of small or thrombosed aneurysms is to be made. Close attention to image acquisition and computer modelling is required to reduce errors in spiral CT angiography of intracranial aneurysms.

Adolescent↗

Use of a metallic stent for relief of symptoms caused by superior vena caval obstruction in a patient with advanced cancer: a case report.

This report describes the insertion of a metallic stent in the superior vena cava to relieve the symptoms of malignant superior vena caval obstruction in a 75-year-old woman with far-advanced lung cancer in whom other methods of symptom control had been ineffective. Her symptoms were quickly relieved by insertion of the stent. She died 1 month following the procedure, without recurrence of the symptoms. The technical aspects of the procedure and the issues affecting the clinical decision-making process in this case are discussed.

Aged↗

Case report: inappropriate use of percutaneous drainage in the management of pancreatic necrosis.

We describe three cases of severe necrotizing pancreatitis, with Apache II scores of 11, 17 and 22, respectively. There was no significant pancreatic parenchymal perfusion in any of the three patients on contrast-enhanced computed tomography. All three patients were primarily treated with percutaneous drains and all three subsequently required open laparotomies. We do not recommend percutaneous drainage as a definitive therapy for severe necrotizing pancreatitis.

Aged↗

Cytokine-mediated bone resorption is cytochrome P-450 dependent. Student Research Award 1998.

Localized bone loss leads to much of the morbidity of chronic otitis media. Although the cellular events of bone remodeling have been well established, their regulation remains poorly understood. Various cytokines, including tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma, used alone and in combination, are powerful inducers of bone resorption. One of the modulators of cytokine-induced bone resorption is nitric oxide (NO), a product of the action of NO synthase (NOS) on L -arginine to form NO. Cytochrome P-450, an enzyme that is similar to NOS both structurally and functionally, may also have a role in NO production in various cellular systems. The goal of this study was to elucidate a possible role of cytochrome P-450 in bone. In this study cytokine-induced bone resorption was blocked with cimetidine and clotrimazole, which are selective inhibitors of the cytochrome P-450 IIIA family and 7-ethoxyresorufin, a nonspecific cytochrome P-450 inhibitor. A concomitant reduction of NO was also observed. This effect may be explained by cytochrome P-450 being a preferred alternative pathway or providing an essential cofactor to NOS in bone.

Animals↗

Spiral CT scanning in the detection and evaluation of aneurysms of the Circle of Willis.

PURPOSE: To assess the utility of spiral computed tomography (CT) with three-dimensional reconstruction in defining aneurysms of the Circle of Willis. METHODS: Eighty-one patients with angiographic or surgical correlation were studied between 1993 and 1995, with surface rendered reconstructions of the arteries of the Circle of Willis. RESULTS: Spiral CT was useful in six clinical situations: further assessment in cases with CT suspicion of an aneurysm, follow-up of known untreated aneurysms or aneurysm remnants, subarachnoid hemorrhage (SAH) with negative angiography, a past or family history of aneurysms, and improved definition of aneurysm anatomy. Ten of fifteen patients with previous surgery had no significant artifacts on the spiral study. In 66 other patients studied in search of aneurysms, the sensitivity of detection was 95% and specificity 74%. Seventeen of nineteen aneurysms 3 mm or less in size and 38 of 39 larger were detected by spiral CT. Four of thirteen patients with SAH and previous negative angiography had aneurysms identified, which were confirmed at surgery. CONCLUSIONS: There is great promise in the use of spiral CT in demonstrating aneurysms of the Circle of Willis, including very small ones. Careful detailing of scan protocols and meticulous examination of multiplanar images are needed for maximum accuracy.

Adolescent↗

The burden of waiting for hip and knee replacements in Ontario. Ontario Hip and Knee Replacement Project Team.

The objectives of this study were to assess the impact of major joint replacements in reducing pain and disability and to describe the burden of pain and disability that could be avoided by ordering the queues with respect to severity of disease. A secondary goal was to compare the uses of a general health status measure, the Short Form Health Survey (SF-36), and a disease-specific measure, the Western Ontario McMaster Osteoarthritis Index (WOMAC), for accomplishing the objectives. The results are based on interviews with 209 patients before and after they had surgery. Only 15.9% of the patients had surgery within 3 months' waiting time, 19.2% waited 4-6 months, 30.7% waited 7-9 months, and the remaining 34.1% waited a year or more. The waiting times were unrelated to the severity of pain or disability reported in the initial interview. Following surgery, there were large reductions in the WOMAC scores for pain, stiffness and difficulty in functioning. The SF-36 showed substantial improvements in relief from pain and in physical functioning, and reductions in role limitation due to physical problems, but not for scores related to mental health. The WOMAC scores were more responsive to the benefits of surgery than the SF-36 scores. Queuing systems keyed on burden of symptoms could reduce the burden of pain and disability suffered by patients awaiting surgery. The improvements from hip and knee replacements suggest that equitable access for these procedures should be a priority in Ontario.

Aged↗

Transcatheter embolization of a congenital intrahepatic arterioportal venous malformation: a case report.

Congenital intrahepatic arterioportal venous malformations (APVM) are uncommon lesions. A congenital intrahepatic APVM found incidentally in a 51-year-old man during pre-operative aortography for an abdominal aortic aneurysm is reported here. This was successfully treated by transcatheter embolization of the involved hepatic artery prior to surgical repair of the aortic aneurysm.

Arteriovenous Malformations↗

Helical computed tomography in the assessment of abdominal aortic pathology.

A pilot study was undertaken to evaluate the role of helical computed tomography in the assessment of abdominal aortic pathology. A total of 17 patients underwent intra-arterial digital subtraction of angiography (IADSA) and helical computed tomography, with eight patients undergoing subsequent operative intervention. A comparison of radiological findings between IADSA and helical computed tomography (CT) was made and, where applicable, a comparison was made with operative findings. Pathology included abdominal aortic aneurysm (AAA) (n = 12), thoraco-abdominal aneurysm (n = 2) and dissection (n = 1), graft distension following AAA repair (n = 1) and plaque haemorrhage in the distal aorta following percutaneous transluminal angioplasty (PTA) of the iliac artery (n = 1). Planned operative management as based on pre-operative helical CT imaging findings, in particular with reference to the type of graft used (straight or bifurcated) was not changed at operation. Our findings on helical CT in regards to AAA, thoroco-abdominal aneurysm and dissection correlated well with angiography and surgery findings.

Aged↗