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Biomedical subjects

E Yuen

Publications and source records attributed to E Yuen.

At least 19 recordsLinked to original sources
PubMed2004

Randomized, placebo-controlled trial of rofecoxib in the acute treatment of migraine.

OBJECTIVE: To investigate the clinical profile of rofecoxib, a long-acting (approximately 17-hour half-life) selective cyclo-oxygenase-2 inhibitor, for the acute treatment of migraine. METHODS: A randomized, double-blind, placebo-controlled, parallel-group study was conducted. Patients age > or =18 treated a moderate or severe migraine headache with placebo (n = 182), rofecoxib 25 mg (n = 183), or rofecoxib 50 mg (n = 192). The primary efficacy measure was headache relief (mild or no pain) 2 hours after dose. RESULTS: The proportions of patients with migraine headache relief at 2 hours after dose were 34.3% for placebo, 54.0% for rofecoxib 25 mg (p < 0.001 vs placebo), and 56.7% for rofecoxib 50 mg (p < 0.001 vs placebo). Rofecoxib 25 and 50 mg were superior to placebo in providing pain freedom at 2 hours, 24-hour sustained headache relief, and 24-hour sustained pain freedom; in reducing photophobia, phonophobia, nausea (50 mg only), and functional disability at 2 hours after dose; and in improving some quality-of-life scores over 24 hours. More patients on rofecoxib 50 mg reported adverse events (39.6%) than patients on rofecoxib 25 mg (26.8%) or placebo (23.6%) regardless of drug relatedness; however, the incidences of drug-related adverse events were similar between treatment groups. These adverse events were generally mild or moderate in severity. The most commonly reported adverse events were dry mouth, dizziness, somnolence, nausea, dyspepsia, paresthesia, and asthenia, with similar incidences between treatment groups. CONCLUSION: Rofecoxib 25 and 50 mg were effective and generally well tolerated for the acute treatment of migraine attacks.

Acute Disease↗
PubMed2003

Unusual neurological presentation of neuroblastoma.

Acute cerebellar ataxia and opsomyoclonus are presenting signs of occult neuroblastoma for a substantial proportion of paediatric patients. Cerebellar ataxia may be due to antibodies against the neuroblastoma cross-reacting with cerebellar tissue. This report is of a 26-month-old boy who presented with encephalitis-like features of ataxia, seizures, decreased consciousness, and involuntary movements. Magnetic resonance imaging of the brain and spine were normal 2 weeks after presentation. The child did not have the classical signs of opsoclonus or myoclonus at any stage of the disease but was found to have occult neuroblastoma. The late demyelinating changes seen on magnetic resonance imaging of the brain support an immunological basis for the paraneoplastic manifestations of occult neuroblastoma in this child. Occult neuroblastoma should be considered as one of the differential diagnoses for children presenting with persisting encephalitis-like features in the presence of normal neuroimaging findings.

Ataxia↗
PubMed2002

MR nerve imaging in a prospective cohort of patients with suspected carpal tunnel syndrome.

OBJECTIVES: To evaluate the reliability and diagnostic accuracy of high-resolution MRI of the median nerve in a prospectively assembled cohort of subjects with clinically suspected carpal tunnel syndrome (CTS). METHODS: The authors prospectively identified 120 subjects with clinically suspected CTS from five Seattle-area clinics. All subjects completed a hand-pain diagram and underwent a standardized nerve conduction study (NCS). The reference standard for determining CTS status was a classic or probable hand pain diagram and NCS with a difference >0.3 ms between the 8-cm median and ulnar peak latencies. Readers graded multiple imaging parameters of the MRI on four-point scales. The authors also performed quantitative measurements of both the median nerve and carpal tunnel cross-sectional areas. NCS and MRI were interpreted without knowledge of the other study or the hand pain diagram. RESULTS: Intrareader reliability was substantial to near perfect (kappa = 0.76 to 0.88). Interreader agreement was lower but still substantial (kappa = 0.60 to 0.67). Sensitivity of MRI was greatest for the overall impression of the images (96%) followed by increased median nerve signal (91%); however, specificities were low (33 to 38%). The length of abnormal signal on T2-weighted images was significantly correlated with nerve conduction latency, and median nerve area was larger at the distal radioulnar joint (15.8 vs 11.8 mm(2)) in patients with CTS. A logistic regression model combining these two MR variables had a receiver operating characteristic area under the curve of 0.85. CONCLUSIONS: The reliability of MRI is high but the diagnostic accuracy is only moderate compared with a research-definition reference standard.

Adult↗
PubMed2001

Phase III randomized trial of gabapentin in patients with amyotrophic lateral sclerosis.

BACKGROUND: Preclinical and clinical studies of gabapentin in patients with ALS led the authors to undertake a phase III randomized clinical trial. METHODS: Patients were randomly assigned, in a double-blinded fashion, to receive oral gabapentin 3,600 mg or placebo daily for 9 months. The primary outcome measure was the average rate of decline in isometric arm muscle strength for those with two or more evaluations. RESULTS: Two hundred four patients enrolled, 196 had two or more evaluations, and 128 patients completed the study. The mean rate of decline of the arm muscle strength was not significantly different between the groups. Moreover, there was no beneficial effect upon the rate of decline of other secondary measures (vital capacity, survival, ALS functional rating scale, timed walking) nor was there any symptomatic benefit. In fact, analysis of the combined data from the phase II and III trials revealed a significantly more rapid decline of forced vital capacity in patients treated with gabapentin. CONCLUSION: These data provide no evidence of a beneficial effect of gabapentin on disease progression or symptoms in patients with ALS.

Acetates↗
PubMed2001

Familial dyskinesia and facial myokymia (FDFM): a novel movement disorder.

We describe here familial dyskinesia and facial myokymia (FDFM), a novel autosomal dominant disorder characterized by adventitious movements that sometimes appear choreiform and that are associated with perioral and periorbital myokymia. We report a 5-generation family with 18 affected members (10 males and 8 females) with FDFM. The disorder has an early childhood or adolescent onset. The involuntary movements are paroxysmal at early ages, increase in frequency and severity, and may become constant in the third decade. Thereafter, there is no further deterioration, and there may even be improvement in old age. The adventitious movements are worsened by anxiety but not by voluntary movement, startle, caffeine, or alcohol. The disease is socially disabling, but there is no intellectual impairment or decrease in lifespan. A candidate gene and haplotype analysis was performed in 9 affected and 3 unaffected members from 3 generations of this family using primers for polymorphic loci closely flanking or within genes of interest. We excluded linkage to 11 regions containing genes associated with chorea and myokymia: 1) the Huntington disease gene on chromosome 4p; 2) the paroxysmal dystonic choreoathetosis gene at 2q34; 3) the dentatorubral-pallidoluysian atrophy gene at 12p13; 4) the choreoathetosis/spasticity disease locus on 1p that lies in a region containing a cluster of potassium (K+) channel genes; 5) the episodic ataxia type 1 (EA1) locus on 12p that contains the KCNA1 gene and two other voltage-gated K+ channel genes, KCNA5 and KCNA6; 6) the chorea-acanthocytosis locus on 9q21; 7) the Huntington-like syndrome on 20p; 8) the paroxysmal kinesigenic dyskinesia locus on 16p11.2-q11.2; 9) the benign hereditary chorea locus on 14q; 10) the SCA type 5 locus on chromosome 11; and 11) the chromosome 19 region that contains several ion channels and the CACNA1A gene, a brain-specific P/Q-type calcium channel gene associated with ataxia and hemiplegic migraine. Our results provide further evidence of genetic heterogeneity in autosomal dominant movement disorders and suggest that a novel gene underlies this new condition.

Adolescent↗
PubMed2001

Diagnosis of carpal tunnel syndrome: electrodiagnostic and magnetic resonance imaging evaluation.

In clinically diagnosed CTS without symptoms or signs to suggest other disorders that can mimic CTS, it is unclear whether performing nerve conduction studies are cost-effective. An outcome study to determine whether nerve conduction studies are necessary for the diagnosis may help to clarify this issue. Even less evidence exists regarding the cost-effectiveness of imaging for CTS. MR imaging reliably depicts normal carpal tunnel anatomic details, including the median and ulnar nerves as well as their intraneural fascicular structure. It can also identify pathologic nerve compression and mass lesions that compress nerves such as ganglion cysts. Currently, MR imaging is probably most commonly used to image patients with ambiguous electrodiagnostic studies and clinical examinations. In the near future, MR diffusion-weighted imaging should be possible for peripheral nerves. As is the case with brain imaging, diffusion-weighted imaging of peripheral nerves is likely to be the most sensitive imaging modality for the detection of early nerve dysfunction. Electrodiagnostic studies are likely to remain the pivotal diagnostic examination in patients with suspected CTS for the foreseeable future. With advances in software and hardware, however, high-resolution MR imaging of peripheral nerves should become faster, less expensive, and probably more accurate, possibly paving the way for an expanded role in the diagnosis of this common syndrome.

Carpal Tunnel Syndrome↗
PubMed2001

Introduction of water conservation education packages: the opportunites and constraints affecting their success.

The Remote Area Developments Group in the Institute for Environmental Science at Murdoch University developed a video and booklet education package on water conservation. The package was developed after research, review of current efforts in water conservation, and consultation with communities showed that there was a need in this area. The package was distributed to all communities within Western Australia. Several different workshops were conducted with Indigenous Environmental Health Workers from around Western Australia in remote areas and in the Perth Metropolitan communities using the package. This paper will briefly describe the opportunities and constraints that exist for water conservation in remote Aboriginal communities in Western Australia as well as give an evaluation of the education package based on workshops, trials and survey instrument. This paper will explain the conclusions that have been drawn from the study: that a broad delivery style is the most advantageous style for remote communities, allowing the facilitator to assess the best style of delivery.

Australia↗
PubMed2001

Water harvesting techniques for small communities in arid areas.

Limited water resources exist in numerous remote indigenous settlements around Australia. Indigenous people in these communities are still living in rudimentary conditions while their urban counterparts have full amenities, large scale water supplies and behavioral practices which may not be appropriate for an arid continent but are supported by extensive infrastructure in higher rainfall coastal areas. As remote indigenous communities continue to develop, their water use will increase, and in some cases, costly solutions may have to be implemented to augment supplies. Water harvesting techniques have been applied in settlements on a small scale for domestic and municipal purposes, and in the large, broadacre farm setting for productive use of the water. The techniques discussed include swales, infiltration basins, infiltration trenches and "sand dam" basins. This paper reviews the applications of water harvesting relevant to small communities for land rehabilitation, landscaping and flood control. Landscaping is important in these communities as it provides shelter from the sun and wind, reduces soil erosion and hence reduced airborne dust, and in some cases provides food and nutrition. Case studies of water harvesting systems applied in the Pilbara Region, Western Australia for landscaping around single dwellings in Jigalong and Cheeditha, in a permaculture garden in Wittenoon and at a college and carpark in Karratha are described.

Agriculture↗
PubMed2000

B7-2-positive myeloma: incidence, clinical characteristics, prognostic significance, and implications for tumor immunotherapy.

Deficiencies in B7:CD28 costimulation are considered to be one of the major causes of the failure to generate a tumor-specific immune response. Up-regulating the expression of the B7 molecules on malignant B cells has been shown to stimulate cytotoxic T cells. Plasma cells from patients with myeloma express a tumor-specific idiotype but lack CD80 (B7-1) and have a variable expression of CD86 (B7-2). This study has identified the incidence and clinical significance of high CD86 expression on plasma cells at diagnosis and studied the ability of trimeric human CD40 ligand (huCD40LT) to up-regulate the expression of the B7 family on malignant plasma cells. CD86 expression on plasma cells was increased in 54% of the patients studied at diagnosis (n = 35) and was associated with a significantly shorter survival (median, 28 versus 57 months; chi(2) = 4.6; P =.03) and a higher tumor load (patients with more than 50% bone marrow plasma cells, 47% versus 6%; chi(2) = 7.2; P =.005). CD86 expression was highest on immature and primitive plasma cells (CD38(++), CD45(+)) of both patients and controls and was associated with a CD40(+), CD20(+), CD19(-), CD138(+) phenotype. The shortened survival was associated with high CD86 only on mature (CD38(++), CD45(-)) plasma cells (chi(2) = 7.6; P =.006). There was no significant correlation between high CD86 and other known prognostic markers, including serum beta(2)-microglobulin, serum thymidine kinase, and labeling index. The addition of huCD40LT to short-term cultures up-regulated both CD80 and CD86 expression on B cells (CD19(+)) and CD80 on plasma cells (CD38(++)), but did not up-regulate CD86 expression on plasma cells. Thus, B7-2-positive myeloma consists of a subgroup of patients with a relatively poor prognosis, and CD40LT may be useful in immunotherapy protocols because it up-regulates CD80 expression on malignant plasma cells without inducing B7-2-positive myeloma. (Blood. 2000;96:1274-1279)

Adult↗
PubMed2000

Electrodiagnostic features of hereditary neuropathy with liability to pressure palsies.

OBJECTIVE: Because diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) frequently is missed or delayed, we looked for electrodiagnostic features that raise suspicion of the disorder by making comparisons with two more common diseases that mimic it electrophysiologically: chronic inflammatory demyelinating polyneuropathy (CIDP) and diabetic polyneuropathy. METHODS: A retrospective review of the neuromuscular laboratory database was performed. RESULTS: Nine HNPP subjects, 22 with CIDP and 49 with diabetic polyneuropathy. Of all the HNPP nerves studied, abnormally slow sensory nerve conduction velocity (SNCV) was found in 93%, prolonged distal motor latencies (DML) in 78%, slow motor nerve conduction velocity in 31%, and prolonged F-wave latencies in 90%. Mean SNCV for HNPP was 85.6%+/-10.6% of the lower limit of normal and significantly slower than for CIDP (114.3%+/-20.1%; p<0.0001) or diabetes (108.1%+/-14.8%; p<0.0001). Excluding the carpal tunnel site from the analysis did not alter this observation: Mean DML were more prolonged in HNPP, even without median nerve data in the analysis (118.5%+/-31.0% of the upper limit of normal), than in CIDP (103.2%+/-31.6%; p<0.05) or diabetes (86.3%+/-18.3%; p<0.0001). Mean HNPP motor nerve conduction velocity was within normal limits. CONCLUSIONS: According to findings, hereditary neuropathy with liability to pressure palsies (HNPP) has a distinctive background polyneuropathy independent of superimposed entrapment neuropathy. It is characterized by diffuse sensory nerve conduction velocity (SNCV) slowing and prolongation of distal motor latencies with relatively infrequent and minor reduction of motor nerve conduction velocities. This indicates disproportionate distal conduction slowing in the disorder.

Adolescent↗
PubMed2000

T-cell expansions in patients with multiple myeloma have a phenotype of cytotoxic T cells.

The presence of T-cell clones in peripheral blood has been previously shown to be associated with a survival advantage in patients with multiple myeloma and suggests that the expanded T-cell populations may be involved in an anti-tumour response. We studied the T-cell receptor (TCR) repertoire of 38 patients with myeloma to identify and characterize the expanded T-cell populations by flow cytometry. T-cell expansions were found in 79% of the patients. The expansions occurred randomly among the 21 variable regions of the TCR beta chain (Vbeta) studied, representing 62% of the V-beta repertoire, and were stable during an 18-month follow-up. The phenotype of the expanded V-beta populations was predominantly CD8+, CD57+, CD28- and perforin+, which differed significantly from the other non-expanded Vbeta populations. The expression of the apoptosis markers Fas (CD95) and bcl-2 were similar between the expanded and non-expanded Vbeta populations. In conclusion, expanded T-cell populations were frequent in patients with myeloma, they remained unchanged during follow-up and had phenotypic characteristics of cytotoxic T cells. These data add further support to the concept that the T-cell expansions may have an immunoregulatory role in myeloma.

Aged↗
PubMed2000

Family poisoned by mercury vapor inhalation.

Acute mercury vapor poisoning is an uncommon but potentially fatal toxicologic emergency. A case series is presented of a family who became exposed to mercury vapor as a result of home gold ore processing. The severity of the poisoning necessitated mechanical ventilation in three of the eight patients who were exposed. Despite aggressive management, two patients died, because their clinical course was dominated by irreversible pulmonary toxicity. The remaining survivors developed varying degrees of mercury toxicity. The pathophysiology, clinical presentation and current treatment guidelines for acute mercury vapor poisoning are emphasized.

Adolescent↗
PubMed1998

The expression of T cell related costimulatory molecules in multiple myeloma.

Presentation of tumour antigen by malignant cells not expressing costimulatory molecules is considered to be a major cause of the failure of the host's immune response against tumours. This study has determined the expression of the B7 family of costimulatory molecules on malignant plasma cells and the expression of the counter receptor molecules, CD28 and CD152 (CTLA-4), on T cells of patients with multiple myeloma. CD28 expression was present on most CD4 cells but was lower on CD8 cells especially from those patients who also showed evidence of expanded T cell clones (median 40%. z=2.4; p<0.02). CD152 expression was increased in 50% (9/18) of patients with myeloma. CD80 (B7-1) expression was present on the plasma cells of only 1 of 27 samples but CD86 (B7-2) expression within the normal range was present on the plasma cells of 14 of 27 samples. Primitive plasma cells (CD38++ CD45++) had a higher expression of CD86 (median 78%) than mature plasma cells (CD38++ CD45-) (median 19%, z=3.7; p<0.01). Thus patients with expanded T cell clones have a downregulated T cell CD28 expression and lack B7-1 expression on their malignant plasma cells. These results are consistent with the concept that engagement of the T cell receptor by tumour antigen on B7-1 deficient malignant plasma cells would result in T cell anergy rather than productive immunity.

Abatacept↗
PubMed1997

The prognostic significance of T cell receptor beta gene rearrangements and idiotype-reactive T cells in multiple myeloma.

Clonal T cell populations with idiotype specificity are present in the peripheral blood of a proportion of patients with multiple myeloma. We have identified the presence of both T cell subpopulations with a specificity for autologous immunoglobin fragments and T cell receptor beta gene rearrangements in peripheral blood samples of patients with myeloma. T cell receptor beta gene rearrangements were detected in 38 of 119 patient samples (32%) and were more common in progressive disease (70%), than at diagnosis (25%) or in stable disease (23%). The 38 patients who had T cell receptor beta gene rearrangements detected at any time had a better overall survival (median not yet achieved) than the patients who never had rearrangements detected (median 45 months, n = 49; chi2 = 6.2, P < 0.01). All 12 patients with T cell receptor beta gene rearrangements at diagnosis are still alive whereas the median survival for 28 patients with a germline configuration at diagnosis was 40 months (chi2 = 5.8, P > 0.01). The presence of T cell receptor beta gene rearrangements even conferred a survival advantage during progressive disease (median survival 44 months vs 19 months; chi2 = 8.7, P < 0.003). Two colour flow cytometry with biotinylated autologous immunoglobulin fragments demonstrated idiotype-reactive T cells in the peripheral blood of five out of 15 patients all of whom had T cell gene rearrangements. The remaining 10 patients had neither idiotype-reactive T cells nor a detectable T cell receptor beta gene rearrangement in concurrent samples. Thus in patients with myeloma there was a good correlation between the presence of T cell receptor beta gene rearrangements and idiotype-reactive T cells. Patients with a rearranged T cell receptor beta gene had a significantly better prognosis.

Aged↗
PubMed1990

Immunophenotypic analyses of cultured hemopoietic mast cells.

Immunophenotypic analyses of immature stage (day 19-23), intermediate stage (day 28-32), mature stage (day 34-37), and older stage (day 42-44) human hemopoietic mast cells from colonies grown in semi-solid agar cultures were performed to study the ontogeny and identity of this cell type and its relationship to other leukocytes. Intermediate to mature stage mast cells were positive with the YB5.B8 mouse monoclonal antibody, (McAb) specific for human mast cells, whereas the reactivity of immature mast cells with this McAb was inconsistent and older cells were generally negative. Mast cells at all stages of maturation were strongly positive for IgE receptor sites and negative with the Bsp-1 McAb, specific for human basophils. Mast cells at all stages of maturation were also strongly positive with the monocyte McAbs RPA-M1 (CD11), positive with the monocyte McAb OKM5 and the monocyte/granulocyte McAbs BMA-210 and MY7 (CD13), strongly positive with the B-cell markers J5 (CD10) and anti-IgM, and positive with the plasma cell marker PCA-1 and to a lesser extent with the activated B-cell marker CD23. The mast cells were also strongly positive with anti-CD45 to the common leukocyte antigen and positive with an antibody to HLA-DR and an antibody to FVIIIC. They were negative for specific T-cell markers. The diversity of this phenotype supports the current concept that mast cells originate from the pluripotential progenitor cells in the bone marrow.

Antibodies, Monoclonal↗
PubMed1988

Post bone marrow transplant sera and persisting mast cell colonies.

Serum samples were collected from eight recipients of allogeneic bone marrow transplants (BMT) following the normalization of peripheral blood counts. Three patients (11 samples) were in the early engraftment period (less than 6 months post-BMT) and still receiving cyclosporin A or methotrexate and the remaining five patients (18 samples) were in stable engraftment (12-84 months post-BMT) and not on immunosuppressive therapy. All post-BMT serum samples supported the growth of increased numbers of mast cell colonies in long-term agar cultures when compared with normal controls (p less than 0.025-0.005), irrespective of the time from BMT or the presence of clinical graft-versus-host disease (GVHD). In contrast, the numbers of neutrophil, monocyte and eosinophil colonies were equivalent in test and control groups. It is proposed that post-BMT sera contain higher levels of a mast cell stimulating activity(s) than does normal sera. Such increased levels might be associated with clinical or subclinical GVHD.

Blood Physiological Phenomena↗