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Biomedical subjects

F Ong

Publications and source records attributed to F Ong.

At least 19 recordsLinked to original sources
PubMed2005

Attojoule calorimetry of mesoscopic superconducting loops.

We report the first experimental evidence of nontrivial thermal behavior of the simplest mesoscopic system--a superconducting loop. By measuring the specific heat C of an array of 450,000 noninteracting aluminum loops with very high accuracy of approximately 20 fJ/K, we show that the loops go through a periodic sequence of phase transitions (with a period of an integer number of magnetic flux quanta) as the magnetic flux threading each loop is increased. The transitions are well described by the Ginzburg-Landau theory and are accompanied by discontinuities of C of only several thousands of Boltzmann constants kB.

Journal Article↗
PubMed2003

Synchronous, bilateral breast cancer: prognostic value and incidence.

The purpose of this study was to address the question whether patients with bilateral breast cancer (BBC) have a worse prognosis in terms of recurrence and survival than patients with primarily unilateral breast cancer (UBC) following breast-conserving treatment (BCT). From 1983 to 2000, a total of 1760 BCT were registered in the Radiotherapy Department of the Medisch Spectrum Twente. We defined synchronous a BBC as cancer diagnosed in both breasts at the same time or within a period of 3 months of diagnosis of the first tumor. One thousand seven hundred and sixty BCT were performed on 1705 patients, 26 of whom presented with BBC. Of these 26 patients, 18 had BCT for both breasts. A higher proportion of patients with BBC showed more tubular carcinoma (P=0.029) and medially located tumors (P=0.076) than those with UBC did. The 5- and 10-year local recurrence rates (LRRs) were 4.5% and 9.1%, respectively, in BBC patients, as against 3.3% and 7.6% for UBC after BCT. The 5- and 10-year distant metastasis rates were 26.9% and 50.7%, respectively, for BBC as against 13.4% and 21.1% for UBC after BCT (P=0.065 and P=0.014, respectively). The 5- and 10-year disease-specific survival (DSS) rates for the 1705 patients were 82.1% and 41%, respectively, after BBC, and 91.4% and 84% after UBC (P=0.086 and P=0.0045, respectively). Patients with BBC have a higher rate of distant metastasis and a worse DSS than those with UBC. As the LRR is similar for BBC and UBC, BCT is not contraindicated in BBC. The incidence of BBC is low, at 1.5% which makes it difficult to reach any more definitive conclusions on outcome and treatment.

Adult↗
PubMed2001

Apoptosis, proliferation and p53, cyclin D1, and retinoblastoma gene expression in relation to radiation response in transitional cell carcinoma of the bladder.

PURPOSE: To determine whether the apoptotic index, the Ki67 index, and the expression of the p53, cyclin D1, and retinoblastoma genes correlate with local control, overall survival, and time to distant metastases in invasive bladder cancer treated with external beam radiation. METHODS AND MATERIALS: Paraffin-embedded pretreatment biopsies from 83 patients with invasive transitional cell carcinoma of the bladder were scored morphologically for apoptosis and immunohistochemically for Ki67, p53, cyclin D1, and retinoblastoma gene expression. Survival analysis methods were used to assess overall survival, local control, and freedom from distant metastases. A multiple proportional hazard (PH) regression analysis was performed to study the prognostic value of the abovementioned biologic parameters (all divided into two categories, except Ki67) in addition to classical prognostic factors such as T stage, histologic grade, multifocality of the tumor, and completeness of transurethral resection. All patients were treated with external beam radiation as sole treatment. Median follow-up for the 19 patients still living was 7.5 years. RESULTS: Apoptotic index varied from 0% to 3.4% with a mean of 0.8% and a median of 0.6%. Ki67 index varied from 0% to 60% with a mean of 14% and a median of 12%. P53 protein was detectable in 61% of the tumors. Overexpression of cyclin D1 was observed in 39% of the tumors and loss of retinoblastoma protein in 23% of the tumors. High Ki67 index was found to be significantly associated with p53 expression (p = 0.04) and cyclin D1 overexpression (p = 0.023). Cyclin D1 overexpression was found more often in Rb-positive tumors than in Rb-negative tumors (p = 0.006). Other associations between the markers are less clear. Biologic markers were not correlated with T stage or grade. In the PH analysis local control was found to be significantly better for tumors with wild-type p53 (p = 0.028). Also, tumors with an apoptotic index above the median value (0.6%) had a significantly better local control rate (p = 0.035). Ki67 index (p = 0.35), retinoblastoma gene expression (p = 0.30) and cyclin D1 overexpression (p = 0.61) were not found to have an additional predictive value regarding local tumor control. None of the tested biologic parameters were found to be associated with overall survival. Time to distant metastases was significantly shorter for tumors with high Ki67 index (p = 0.01) and tumors with an apoptotic index less than median (p = 0.009). CONCLUSIONS: The results of our study provide evidence for a prognostic value of p53 expression and apoptotic index with respect to the radiation response in bladder cancer in addition to more conventional prognosticators. The value of these parameters as a predictive assay for radiation response warrants confirmation in larger and prospective studies.

Adult↗
PubMed2001

Prognostic factors in transitional cell cancer of the bladder: an emerging role for Bcl-2 and p53.

BACKGROUND AND PURPOSE: In a recent study on patients with transitional cell cancer of the bladder treated with curative radiotherapy following TUR-T, we demonstrated that a low apoptotic index and p53 positivity were associated with poor local control. The purpose of this study was to assess the prognostic significance of additional markers implicated in regulation of cell cycle and apoptosis. PATIENTS AND METHODS: Bcl-2, Bax and p21 positivity were detected immunohistochemically on paraffin-embedded pre-treatment biopsies from 83 patients with invasive transitional cell cancer (TCC) of the bladder, treated with radiotherapy. In addition, markers determined in an earlier analysis, i.e.: p53, apoptotic index, cyclin D1, retinoblastoma protein and Ki-67 were included in the multivariate analysis. A stepwise proportional hazard analysis was performed, adjusting for classic prognostic factors (T-stage, grade, multifocality and macroscopic completeness of the TUR). Positivity was defined as >10% of tumor cells staining positive for Bcl-2, Bax and p21, and >20% for p53. RESULTS: Bcl-2 positivity was found in 63%, Bax was positive in 52% and p21 in 55% of cases. In the PH analysis Bcl-2 positivity was found to be related to poor local control (36 vs. 72% at 3 years; P=0.003), as well as to shorter disease-specific survival (74 vs. 94% at 3 years; P=0.017). Evidence for an adverse effect of p53 positivity was also found (local control: 32 vs. 69% at 3 years;P=0.037, disease-specific survival: 76 vs. 92% at 3 years; P=0.043). In an additional PH analysis, we found poor local control rates for bladder cancers with combined Bcl-2 and p53 positivity (17 vs. 65% at 3 years; P=0.0017), and lower disease specific survival (60 vs. 92%; P=0.0024), disease-free survival (7 vs.35%, P=0.0023) and overall survival (39 vs. 80%; P=0.0018). CONCLUSION: This study provides evidence for a poor outcome in patients treated with radiotherapy for TCC of the bladder expressing both Bcl-2 and p53. This relationship was found for local control and disease-free, disease-specific and overall survival.

Adult↗
PubMed2000

Case-control study of risk factors for human infection with a new zoonotic paramyxovirus, Nipah virus, during a 1998-1999 outbreak of severe encephalitis in Malaysia.

An outbreak of encephalitis affecting 265 patients (105 fatally) occurred during 1998-1999 in Malaysia and was linked to a new paramyxovirus, Nipah, that infected pigs, humans, dogs, and cats. Most patients were pig farmers. Clinically undetected Nipah infection was noted in 10 (6%) of 166 community-farm controls (persons from farms without reported encephalitis patients) and 20 (11%) of 178 case-farm controls (persons from farms with encephalitis patients). Case patients (persons with Nipah infection) were more likely than community-farm controls to report increased numbers of sick/dying pigs on the farm (59% vs. 24%, P=.001) and were more likely than case-farm controls to perform activities requiring direct contact with pigs (86% vs. 50%, P=.005). Only 8% of case patients reported no contact with pigs. The outbreak stopped after pigs in the affected areas were slaughtered and buried. Direct, close contact with pigs was the primary source of human Nipah infection, but other sources, such as infected dogs and cats, cannot be excluded.

Agricultural Workers' Diseases↗
PubMed2000

Risk factors for Nipah virus transmission, Port Dickson, Negeri Sembilan, Malaysia: results from a hospital-based case-control study.

A hospital-based case-control study of viral encephalitis was carried out at Port Dickson Hospital, in the state of Negeri Sembilan, Malaysia. Between March and May 1999, 69 clinically diagnosed viral encephalitis cases and 31 controls were interviewed. Job histories on pig farming activities were assessed by a group of epidemiologists and veterinary surgeons. Results show that among clinical cases of viral encephalitis, 52 (75.4%) cases were diagnosed to have Nipah virus infection based on positive serology for antibodies to the cross-reacting Hendra virus antigen. The Nipah virus encephalitis was significantly associated with a history of working in pig farms (p < 0.001, OR = 196.0, 95% CI = 20.4-4741.6), history of contact with animals (p < 0.001, OR = 38.3, 95% CI = 8.2-209.0) and with history of direct contact with pigs (p = 0.002, OR = 34.4, 95% CI = 2.6-1,024.4). The Nipah virus infection was also significantly associated with history of feeding/cleaning pigs (p < 0.001, OR = 102, 95% CI = 11.9-2,271.5). These results provide evidence that involvement in pig farming activities is significantly associated with the risk of getting Nipah virus infection. They are potential risk factors for Nipah virus transmission in the major pig-producing area of Bukit Pelandok, Port Dickson Negeri Sembilan.

Adolescent↗
PubMed1999

Serum interleukin-6 has no discriminatory role in paraproteinaemia nor a prognostic role in multiple myeloma.

We determined interleukin-6 (IL-6) levels in the serum of 212 well-defined patients with newly diagnosed paraproteinaemia and evaluated its discriminatory value and prognostic role in multiple myeloma (MM). Results were compared with serum neural cell adhesion molecule and beta-2-microglobulin, both established prognostic MM markers. Paraproteinaemia-related diagnoses were: MM (60), other haematological diseases (46), solid tumours (35), autoimmune diseases (17) and monoclonal gammopathy of unknown significance (MGUS) (54). The range of IL-6 levels in all diagnostic groups overlapped widely and did not serve as a discriminatory marker in newly diagnosed paraproteinaemia even when patients with infection or fever (42) were excluded. In MM high IL-6 levels (>/= 50 pg/ml) were not associated with a shorter survival (P = 0.24). We compared our results with 20 published studies on serum IL-6 in paraproteinaemia and/or MM. IL-6 data have to be related to the assay used (bio- or immunoassay) and to the status of MM (newly diagnosed, during therapy, progressive disease). We conclude that serum IL-6 is not specific for paraproteinaemia-related diseases and will not serve as a reliable discriminatory or prognostic marker in paraproteinaemia and MM.

C-Reactive Protein↗
PubMed1998

[The risk of a multiple myeloma in patients with paraproteinemia: a myeloma risk score developed in the region of the Comprehensive Cancer Center West].

Diagnoses in patients with paraproteinaemia are diverse; few (mostly single centre based) studies are known that describe incidence, diagnoses and follow-up in patients with paraproteinaemia. In the region of the Comprehensive Cancer Centre West in the Netherlands (population 1.6 million, 1992) a population-based registry was set up in the period 1991-1993. Patients (n = 1464; median age: 72 years; range: 16-102) were entered by clinical chemists, internists, haematologists, and pathologists. Multiple myeloma and plasmacytoma were diagnosed in 261 patients (18%), paraprotein-related haematological diseases in 159 patients (11%) and paraprotein-related internal diseases in 210 patients (14%). After bone marrow examination monoclonal gammopathy of unknown significance (MGUS) was diagnosed in 207 (14%) patients. No further diagnosis could be made in 627 (43%) patients mostly for lack of supplementary bone marrow and (or) X-ray examinations. Consequently, more than two-thirds of all patients with a newly found paraprotein did not show any sign of a haematological malignancy. Using these data a 'myeloma risk score' was developed to predict the presence of a multiple myeloma based on paraprotein type and concentration, aiding the physician in determining which patients should undergo further bone marrow and skeletal examinations.

Adolescent↗
PubMed1997

Developing a population-based registry for patients with paraproteinemias or multiple myeloma.

The development of a population-based registry on paraproteinemia and multiple myeloma is described. A unique feature of this registry is the multidisciplinary approach to obtain and collect new cases. Clinical chemists, internists, hematologists, and pathologists could all enter patients. All patients newly diagnosed in the mid-western part of The Netherlands (1.7 million inhabitants in 1992) with a paraproteinemia or multiple myeloma in 1991, 1992, and 1993 were included. The project was composed of a registry of clinical and laboratory data extracted from the patient's records, storage of 1 ml serum at diagnosis, and a yearly follow-up. A total of 1832 entries was received, of which 83% met the inclusion criteria. Comparison of this database with the Regional Cancer Registry showed that the paraprotein registry was successful as far as registration of myeloma patients was concerned. We conclude that the multidisciplinary approach used in this paraprotein registry is feasible and has resulted in a unique collection of patients for studying potential pre-malignant conditions such as paraproteinemia.

Diagnosis, Differential↗
PubMed1997

A population-based registry on paraproteinaemia in The Netherlands. Comprehensive Cancer Centre West, Leiden, The Netherlands.

Patients with monoclonal gammopathies comprise a heterogenous group. The few studies on incidence and follow-up are single-centre-based and may reflect referral bias. To avoid this, all patients (n=1275) in midwestern Netherlands with a newly discovered paraproteinaemia in 1991, 1992 and 1993 were included in a population-based registry and divided into four major diagnostic groups: multiple myeloma and plasmacytoma (n=230, 18%), other haematological diseases (n=141, 11%), paraprotein-related internal diseases (n=191, 15%) and monoclonal gammopathy of undetermined significance (MGUS, n=713, 56%). To avoid a possibly erroneous diagnosis, patients who were classified as having MGUS but who did not undergo confirmatory bone marrow examination were included in a separate group 'provisional MGUS' (n=524, 41%), whereas patients who did were classified as having 'definite MGUS' (n=189, 15%). The 'provisional MGUS' patients were relatively older and had more often a poor performance status, but differences between this and the 'definite MGUS' group were otherwise small. Patients complaining of general malaise more often had a full work-up of their paraproteinaemia. Bone pain, hypercalcaemia, high total protein, and high ESR occurred predominantly in the myeloma group, whereas fever or infection was less often seen in these patients. This registry of patients with paraproteinaemias provided valuable data related to all different diseases associated with paraproteinaemia.

Adult↗
PubMed1997

Development of a "Myeloma Risk Score" using a population-based registry on paraproteinemia and myeloma.

Diagnostic systems for monoclonal gammopathies use bone marrow and X-ray examinations to exclude multiple myeloma (MM). Data from a population-based registry of unselected patients with paraproteinemia indicate that these tests are often done only when MM is suspected. We used 441 randomly selected patients to develop a simple four point "Myeloma Risk Score" based on two readily available laboratory tests. One point was given for paraprotein concentration > or = 10 g/l, one point for IgG and IgA, and two points for IgD and light chains only. A score of 0 or 1 indicated a low risk for MM, with scores of 2 and 3 signifying high risks. Sensitivity, specificity, positive and negative predictive value (PV) for the Myeloma Risk Score in the training sample were 92%, 88%, 79%, and 96% respectively. Extrapolating these results to a larger cohort showed that 90% of patients with a monoclonal gammopathy could be classified correctly as having MM or a non-myeloma condition. The Myeloma Risk Score can identify patients with a paraproteinemia at risk for MM, and who are therefore candidates for bone marrow and X-ray examination.

Biomarkers, Tumor↗
PubMed1996

Serum neural cell adhesion molecule differentiates multiple myeloma from paraproteinemias due to other causes.

Serum neural cell adhesion molecule (NCAM) has been described as a prognostic marker in multiple myeloma (MM). Both C-reactive protein (CRP) and beta 2-microglobulin (beta 2M) are established prognostic markers in MM. We tested the diagnostic value of these markers in 212 serum samples of patients with paraproteinemia registered prospectively in a population-based registry. Sixty patients had MM and 152 had other monoclonal gammopathies (hematologic diseases [48], paraneoplastic disease [35], autoimmune disease [15], and monoclonal gammopathy of undetermined significance [56]). CRP and beta 2M had wide and overlapping ranges in all diagnostic categories. However, serum neural cell adhesion molecule (NCAM) was low (< 20 U/mL) in all but 4 of 152 nonmyeloma cases and high (> or = 20 U/mL) in 31 (52%) of the 60 MM cases. Two patients with non-Hodgkin's lymphoma, 1 with chronic lymphatic leukemia, and 1 with autoimmune disease had serum NCAM values between 20 and 30 U/mL. In a discriminant analysis in which serum NCAM, CRP, beta 2M, paraprotein type and concentration, hemoglobin, leukocyte and thrombocyte counts, creatinine, corrected calcium, lactate dehydrogenase, and alkaline phosphatase were included, paraprotein type and concentration and serum NCAM turned out to be the best combination of parameters predicting whether a patient had MM, with 89% of cases being correctly classified. Even without bone marrow and x-ray examinations, serum NCAM, in combination with paraprotein type and concentration, can differentiate between MM and nonmyeloma patients.

Adult↗
PubMed1995

International Prognostic Index for aggressive non-Hodgkin's lymphoma is valid for all malignancy grades.

An International Prognostic Index (IPI) for patients with aggressive non-Hodgkin's lymphoma (NHL) has recently been published. The IPI is based on pretreatment clinical characteristics and developed on clinical trial patients, classified as intermediate grade according to the Working Formulation (WF). We applied this IPI in a population-based registry of NHL patients. This registry does not have the restrictions that usually hold for patients in clinical trials, eg, with respect to age and performance status. Moreover, it covers all the three WF classes (low, intermediate, and high). The IPI turned out to be of prognostic value for response rate and survival in our unselected cohort of 744 patients, as well. In each of the three WF classes separately, the four IPI classes showed going from low to high substantially decreasing response rates and survival percentages. For our cohort of WF intermediate grade patients 5-year survival levels were lower in all four IPI classes (59%, 34%, 14%, and 10%, respectively), probably reflecting the selection of clinical trial patients in the original study (73%, 51%, 43%, and 26%).

Aged↗
PubMed1995

Presenting signs and symptoms in multiple myeloma: high percentages of stage III among patients without apparent myeloma-associated symptoms.

We studied the medical histories of 127 patients diagnosed with multiple myeloma included in a population-based registry of 945 patients with a para-protein or multiple myeloma in the region of the Comprehensive Cancer Center West (CCCW). We defined patients "not immediately diagnosed" or "delayed diagnosis" as those patients in whom myeloma was not included in the initial differential diagnosis. We found that 37% belonged to this category. These patients more often had symptoms not associated with multiple myeloma. Since a surprising 51% of patients with delayed diagnosis turned out to have stage-III myeloma, the physician should be alert to the presence of this disease, despite the fact that co-morbidity may mask its presence.

Adult↗
PubMed1995

Is the Durie and Salmon diagnostic classification system for plasma cell dyscrasias still the best choice? Application of three classification systems to a large population-based registry of paraproteinemia and multiple myeloma.

There are a number of systems for diagnosing multiple myeloma, myeloma variants and monoclonal gammopathy of undetermined significance. We compared three systems, those according to Durie and Salmon, to Kyle and Greipp, and to the British Columbia Cancer Agency, using material from a population-based registry of 847 patients with a paraproteinemia or multiple myeloma. Of these, 157 underwent both bone marrow and X-ray examinations and were subsequently included in our analysis. The differences between the systems were small, even though in only 64% of the cases the diagnosis according to all three systems was identical. The system used by the British Columbia Cancer Agency turned out to be the shortest and easiest system reviewed here. We propose a more frequent application of this system instead of the more commonly used Durie and Salmon and Kyle and Greipp criteria.

Adult↗
PubMed1995

Bcl-2 protein expression is not related to short survival in multiple myeloma.

The oncoprotein bcl-2 can be expressed in malignant plasma cells and might play a role in the prevention of corticosteroid-mediated apoptosis, thereby prolonging survival of the myeloma cells. We retrospectively investigated whether bcl-2 expression in bone marrow plasma cells measured by two-color fluorescence for immunoglobulin light chains would be related to survival duration in patients suffering from multiple myeloma. In all patients the large majority of plasma cells expressed bcl-2 (median 91%, range 74-100%). Contrary to our expectations, a tendency was observed toward higher percentages bcl-2+ plasma cells in patients with a long survival (more than 5 years, n = 9) vs patients who died from refractory myeloma within a year of diagnosis (n = 7). This tendency was found even when analysis was extended to include four patients in the short diagnosis group (n = 11) who had received chemotherapy prior to bone marrow examination.

Adult↗
PubMed1992

Antenatal care of low risk obstetric patients by midwives. A randomised controlled trial.

OBJECTIVES: To assess the practicality, acceptability to patients and salary costs of the antenatal care of low risk obstetric patients by midwives. DESIGN: A randomised controlled trial. SETTING: The antenatal clinic at Westmead Hospital, a teaching hospital of the University of Sydney in western Sydney. PATIENTS: From January 1989 until November 1990, 89 women booking for full antenatal care at Westmead Hospital and classified as low risk were randomly allocated to one of two groups. Group 1 (43 patients) had their antenatal care provided by registered midwives. Group 2 (46 patients) had their antenatal care provided by an obstetrician (either Visiting Medical Officer or Staff Specialist) in a routine hospital antenatal clinic. INTERVENTIONS: Patients in the midwives' clinic were seen by an obstetrician at their first visit to the antenatal clinic and again at 30 weeks and at 40 weeks. MAIN OUTCOME MEASURES: These were the salary costs of each clinic and the patients' levels of satisfaction. Maternal and neonatal indicators, delivery details and analgesic requirements were also considered. These indicators were planned before data collection commenced. RESULTS: The major differences found were a 28% to 68% salary cost saving and that patients cared for by midwives showed appreciation of the continuity of care and information given at the midwives' clinic. CONCLUSIONS: The care of low risk obstetric patients by midwives in a midwives' clinic showed salary cost savings and high patient acceptance.

Continuity of Patient Care↗