Search PubMed⌕ Search

Biomedical subjects

Y K Lau

Publications and source records attributed to Y K Lau.

At least 37 records · Page 2Linked to original sources
PubMed1997

Pattern of proteinuria in tubular injury and glomerular hyperfiltration.

Proteinuria is one of the bad prognostic indices in renal disease. This study compares the pattern of protein excretion in 10 patients with IgA nephropathy (IgAN), 10 patients with chronic glomerulonephritis approaching end-stage renal failure (ESRF) who still had proteinuria and 10 other patients with diabetic nephropathy (DN) with proteinuria but normal renal function. The pattern of proteinuria was analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing (IEF) and assayed for orosomucoid, alpha-1-microglobulin, retinol-binding protein, lysozyme, beta-2-microglobulin and N-acetyl-beta-D-glucosaminidase activity. Our data showed much similarity in the pattern of proteinuria between the DN and ESRF groups but significant differences with the IgAN group. The pattern of proteinuria in the IgAN group reflects glomerulonephritis whereas the similar pattern between the ESRF and DN groups may reflect hyperfiltration as well as tubular injury.

Adolescent↗
PubMed1997

Strong correlation between c-erbB-2 overexpression and overall survival of patients with oral squamous cell carcinoma.

Overexpression of c-erbB-2 (also known as HER-2/neu) has been found in many human cancers, including head and neck squamous cell carcinoma (SCC). We therefore examined expression of the oncoprotein in oral SCC primary tumor samples and compared its relationship with clinical stages and survival rate. Out of 80 cases of oral SCC, high expression level (++ or +++) of c-erbB-2 was found in 41 cases. Of the 80 cases with follow-up information, 39 were further investigated for the correlation of expression level of c-erbB-2 and survival rate. Overexpression of the oncoprotein was significantly correlated with shorter overall survival, and the patients with low and no expression of c-erbB-2 had much higher survival rates. Overexpression of c-erbB-2 was also significantly correlated with nodal stage and metastasis. We found that high expression level of c-erbB-2 was frequently detected in oral cancer cell lines but not in the other head and neck SCC cell lines. Thus, we conclude that overexpression of c-erbB-2 is a frequent event in oral SCC and is correlated with poor survival and may be used as a poor prognostic factor.

Adolescent↗
PubMed1996

Effects of dobutamine stimulation on myocardial blood flow, glucose metabolism, and wall motion in normal and dysfunctional myocardium.

BACKGROUND: This investigation examines the effects of inotropic stimulation on myocardial blood flow (MBF) and glucose metabolism (MRGlc) in dysfunctional myocardium through the use of positron emission tomography (PET). METHODS AND RESULTS: Nineteen patients with chronic coronary artery disease and 12 normal volunteers were studied with 13N-ammonia, 18F-deoxyglucose, and PET and with two-dimensional echocardiography at baseline and during intravenous dobutamine (5 to 10 micrograms/kg per minute). At rest, MBF in mismatch regions (n = 10) averaged 0.53 +/- 0.19 mL/g per minute and increased by 41.4 +/- 46.6% (P = .01) during dobutamine, whereas in match regions (n = 16) MBF was 0.28 +/- 0.09 mL/g per minute at rest without an increase during dobutamine (26.4 +/- 47.3%; NS). Myocardium with normal rest MBF was classified as normal remote (normal wall motion, n = 8) or abnormal remote (abnormal wall motion, n = 11). Dobutamine raised MBF similarly in normal subjects and in normal remote regions (by 82 +/- 85% and 84 +/- 42%, P < .01) but by only 33 +/- 34% in abnormal remote regions. MRGlc declined by 49 +/- 28% (P < .005) with dobutamine in the normal subjects, remained unchanged in normal and abnormal remote regions of the patients, but increased in mismatch and match regions (by 49 +/- 74% and 46 +/- 77%; P < .05). Wall motion improved with dobutamine only in mismatch and abnormal remote regions but not in match regions. CONCLUSIONS: Blood flow-metabolism mismatch patterns are not consistently associated with a fixed downregulation of MBF; the increased contractile work in response to dobutamine stimulation is associated with an increase in MBF and a greater reliance on glucose utilization, possibly reflecting acute ischemia or alterations in substrate selection by chronically dysfunctional myocardium. Importantly, functionally impaired though normally perfused myocardium frequently exists in chronic coronary artery disease patients and may represent repetitively stunned or, more likely, remodeled left ventricular myocardium.

Adult↗
PubMed1996

Transesophageal echocardiography in the detection of inferior vena cava and cardiac metastasis in hepatocellular carcinoma.

Antemortem diagnosis of inferior vena cava (IVC) and cardiac metastasis of hepatocellular carcinoma (HCC) is difficult but important before consideration of curative resection. There are only a few cases of cardiac metastasis of HCC which have been diagnosed antemortem by echocardiography. Accordingly, 18 consecutive patients with HCC who were potential candidates for curative resection were studied by transthoracic (TTE) and transesophageal echocardiography (TEE). One (6%) and two (11%) patients had cardiac and IVC metastasis of HCC, respectively, which was detected by two-dimensional TTE. In contrast, by using TEE, four patients (22%) showed tumor invasion of the IVC, of whom two (11%) had tumor mass extending into the right atrium (RA). There was no significant difference in age, serum level of alpha-fetoprotein, and percentage of right liver lobar involvement between those with and without cardiac metastasis. Patients without cardiac metastasis detected on TTE or TEE had significantly longer mean duration of survival (5.0 +/- 2.1 vs. 2.1 +/- 1.0 months; p < 0.05). In summary, TEE may be more useful than TTE in the detection of cardiac metastasis of HCC, which occurred in 22% of patients whose primary tumor was considered to be surgically resectable in our series. This can be safely performed in patients with HCC and can provide optimal visualization of the IVC and RA. The high prevalence of subclinical cardiac metastasis in HCC mandates the use of TEE in all patients with HCC prior to surgical intervention.

Age Factors↗
PubMed1996

Case report: lysosomal glycogen storage disease with normal acid maltase: an unusual form of hypertrophic cardiomyopathy with rapidly progressive heart failure.

A 14-year-old boy with mild mental retardation, myopathy, and nonobstructive hypertrophic cardiomyopathy (HCM) with clinical and histopathologic features consistent with lysosomal glycogen storage disease with normal acid maltase is described. The case illustrates the aggressive nature of the cardiomyopathy of this syndrome. This condition is associated with malignant ventricular arrhythmias, relentlessly progressive ventricular dilatation, dysfunction, and sudden death. It is important to recognize this unusual and malignant form of HCM to precipitate low early diagnosis by muscle biopsy. Patients with this condition would be excellent candidates for life-saving heart transplant as the myopathy and mental retardation are mild and nonprogressive. The underlying biochemical defect and mode of inheritance of this syndrome are unclear. However, a significant proportion are genetically related and thus, relatives may benefit from family screening.

Adolescent↗
PubMed1994

Parvovirus B19 outbreak on an adult ward.

In November and December 1992, an outbreak of parvovirus B19 infection occurred among patients and staff on an adult mixed surgical ward at a large hospital in London. Three patients and 15 staff members were serologically confirmed as acute cases. The attack rate among susceptible members of staff was 47%. In those infected, arthralgia (80%) and rash (67%) were the most common symptoms. Of six susceptible in-patients on the ward, three became infected. One of the in-patients who had carcinoma of the mouth was viraemic for more than 10 days with marrow suppression resulting in the postponement of chemotherapy until intravenous immunoglobulin was given and he was no longer viraemic. Control measures taken included closure of the ward to new admissions, transfer of only immune staff to the ward, and restriction of the ward nursing staff to working only on that ward. Although no specific exposure was conclusively identified as a risk factor, there was a suggestion of an increased risk of acquiring parvovirus B19 infection among those staff who did not adopt strict hand washing procedures after each physical contact with a patient (RR = 2.33; P = 0.07). Knowledge of parvovirus B19 among interviewed health care workers was poor: only 42% reported knowing about parvovirus B19 and only 38% could name a patient category at risk of a severe outcome following infection. This is the first report of a nosocomial outbreak affecting an adult ward and of possible transmission of parvovirus B19 infection from staff to in-patients. Hospital control of infection teams should include parvovirus B19 in their outbreak containment plans.

Adult↗
PubMed1994

Isoelectric focusing and selectivity index in IgA nephrotic syndrome.

Proteinuria in 13 patients with IgA nephritis with nephrotic syndrome (IgANS) was analysed by isoelectric focusing (IEF) and compared with 12 patients with minimal change nephrotic syndrome (MCNS) (n = 8) or focal global sclerosis nephrotic syndrome (FGS) (n = 4) to determine the pattern of proteinuria on IEF and to assess the value of IEF and protein selectivity index (SI) as predictors of response to therapy with predisolone or cyclophosphamide. Steroid/cyclophosphamide responsive patients with IgANS had SC:UA (cationic serum albumin with anionic urine albumin) or SA:UC (anionic serum albumin with cationic urine albumin) IEF patterns and steroid/cyclophosphamide unresponsive patients with IgANS had an SC:UC (cationic serum albumin with cationic urine albumin) IEF pattern. The majority of patients with MCNS or FGS who had an SA:UC IEF pattern were steroid responsive. SI was a better predictor of steroid/cyclophosphamide responsiveness in patients with IgANS (r = 0.78, p < 0.002 compared to IEF, r = 0.64, p < 0.02).

Adolescent↗
PubMed1991

Differential oxygen sensitivities in G6PDH activities of cultured keloid and normal skin dermis single cells.

Cell cultures of excised keloids and biopsied normal skin were established from patients of the Plastic Surgery Department of Singapore General Hospital and their single cells quantitated for glucose-6-phosphate dehydrogenase (G6PDH) activity using microspectrophometry. G6PDH has been cited as a transformation-linked discriminant. Analysis of variance shows no difference in overall activity between skin and keloid cells, but under oxygen saturation conditions, keloid G6PDH activity was significantly higher than skin G6PDH activity, although they were almost identical under nitrogen saturation conditions. Differential oxygen sensitivity in G6PDH activities between malignant and non-malignant cells have been reported, but its occurrence between keloid and normal skin cells is novel, especially as the keloid is regarded as a benign tumor with a zero carcinogenicity rate.

Adolescent↗
PubMed1991

Pattern of proteinuria in IgA nephritis by SDS-PAGE: clinical significance.

Of sixty patients with IgA nephritis, none had CRF at first examination, 13 developed CRF with creatinine above 1.6 mg/dl within 6 years. Among these patients who had analysis of proteinuria by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), 31 patients had middle molecular weight (MMW) proteinuria alone (pattern 1), 10 had MMW and Low MW (LMW) or tubular proteinuria (pattern 2), 10 had high MW (HMW) and MMW proteinuria (Pattern 3) and 9 had HMW, MMW and LMW proteinuria (Pattern 4). At the end of a follow up period of 6 years (1983-1989) patients with mixed proteinuria had a higher incidence of chronic renal failure (CRF), 11/29 (38%) compared to those with pattern 1 proteinuria, 2/31 (6%) (chi 2 = 8.7, p less than 0.005). Based on the glomerular selectivity index (GSI), 19 patients had nonselective proteinuria but they did not have a higher incidence of CRF. By the selectivity index (SI), 18 patients had nonselective proteinuria and they showed a significantly higher incidence of CRF. Compared to the 41 patients who did not have LMW proteinuria, 19 patients with LMW proteinuria had more severe proteinuria. After a follow-up period of 6 years, patients with LMW proteinuria had a higher incidence of CRF (10% versus 47%, p less than 0.001). The presence of LMW proteinuria indicates a less favourable outcome and the pattern of proteinuria as assessed by the SDS-PAGE appears to be a better prognostic index in IgA nephritis than the SI and the GSI.

Adult↗
PubMed1991

Effects of triple therapy in IgA nephritis: a follow-up study 5 years later.

This study is a 5-year post trial assessment of patients with IgA nephritis who entered a 3-year prospective controlled trial of cyclophosphamide, dipyridamole (D) and low-dose warfarin (W). Patients entered the trial from 1979 to 1981 and the trial ended in 1984 with those in the treatment group having more stable renal function and less proteinuria compared to the control group. Present reassessment of the patients in 1989 showed no difference in the renal function between those in the treatment group (n = 27) and the control group (n = 21). 6 patients in the treatment group and 7 in the control group were in ESRF. At the conclusion of the trial in 1984, among the 27 patients in the original treatment group, 13 patients elected to continue with D + W while the other 14 patients chose to cease therapy and therefore served as the new control group. 5 years later, renal function in the new treatment group (n = 13) was significantly stable compared to the new control group (n = 14), (serum creatinine 1.4 +/- 0.7 versus 4.4 +/- 3.2 mg/dl, p less than 0.01). Furthermore, all the 6 patients with ESRF in the original treatment group of 27 patients were from the new control group (n = 14) where treatment with D + W had been ceased. None of the patients still on D + W are in ESRF.

Adult↗
PubMed1989

The simultaneous determination of active ingredients in cough-cold mixtures by isocratic reversed-phase ion-pair high-performance liquid chromatography.

A simple, rapid and accurate method for the simultaneous determination of active ingredients in cough-cold mixtures using isocratic reversed-phase ion-pair high-performance liquid chromatography has been developed. It involves the use of an octadecylsilane column as the stationary phase with methanol, water, tetrahydrofuran, phosphoric acid mixtures as mobile phase including sodium dioctylsulphosuccinate as the ion-pair agent. The pH of the mobile phase was adjusted to 4.6 by means of phosphoric acid and ammonium hydroxide solutions. The proposed method involves the simple dilution of the samples with the mobile phase and the addition of metoclopramide hydrochloride as the internal standard. The active ingredients under investigation were chlorpheniramine, codeine, diphenhydramine, ephedrine, ethylmorphine, phenylephrine, phenylpropanolamine and pholcodine, which exist as various combinations in cough-cold mixtures. The optimum composition of the mobile phase and the optimum flow rate were determined and are reported. The method was applied to the determination of active ingredients in seven commercially available cough-cold mixtures.

Antitussive Agents↗
PubMed1989

Protein selectivity: a prognostic index in IgA nephritis.

Among 98 patients with IgA nephritis who had protein selectivity studies performed, 54% had nonselective proteinuria and the remaining 46% had selective proteinuria. Patients with nonselective proteinuria had a higher incidence of glomerulosclerosis. At the end of a 4-year follow-up period, patients with nonselective proteinuria had lower creatinine clearance, higher incidence of hypertension and chronic renal failure when compared to patients with selective proteinuria. Six out of eleven patients (55%) in the study who had the nephrotic syndrome had selective proteinuria. Among these 6 patients, 1 had spontaneous remission and 5 responded to steroid or cyclophosphamide therapy. The remaining 5 patients with nonselective proteinuria did not respond to therapy. In the patients who had selectivity studies repeated, the data showed that the selectivity index (SI) can fluctuate depending on the clinical course of the patients. SI can therefore be used to monitor the progress of patients on long-term follow-up. Protein selectivity appears to be a useful prognostic index in IgA nephritis. For patients with the nephrotic syndrome it may serve as a guide to therapy.

Adult↗