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Biomedical subjects

F M Lai

Publications and source records attributed to F M Lai.

At least 127 records · Page 7Linked to original sources
PubMed1987

Pattern of glomerulonephritis in Chinese population: the effect of renal biopsy on the therapeutic decision.

A retrospective analysis of 190 consecutive renal biopsies was undertaken to assess the pattern of glomerulonephritis in Chinese, and the role of renal biopsy in paediatric nephrology. Minimal change nephropathy, IgA nephropathy and membranous nephropathy comprised 41%, 16% and 13% of primary glomerular diseases, respectively. Minimal change nephropathy accounted for only 61% of patients with idiopathic nephrotic syndrome. In 76 patients the provisional clinicopathological diagnosis was shown to be incorrect or uncertain, and correct diagnosis was made solely on histological examination. In 47 cases a substantial change in therapy occurred on the basis of biopsy results. These data suggest that the practice of renal biopsy in paediatric nephrology performed appropriately in carefully selected patients is a useful procedure.

Adolescent↗
PubMed1987

Papillary necrosis associated with rifampicin therapy.

We report a patient who developed progressive renal failure following 13 months of rifampicin therapy for renal tuberculosis. The renal function continued to deteriorate despite the discontinuation of rifampicin. Renal pathology did not demonstrate any evidence of tuberculosis of the kidney but revealed the unique pathological finding of glomerulosclerosis, granulomatous interstitial nephritis, and extensive papillary necrosis.

Adult↗
PubMed1987

Hemofilter reuse in maintenance hemofiltration.

The practice of multiple use of hemofilter was examined on 16 patients in our dialysis center. The hemofilters were cleaned by reverse ultrafiltration using positive pressure in the blood and filtrate compartment of the hemofilter. Ten hemofilters used for continuous arteriovenous hemofiltration, 6 hemofilters used for pump-assisted acute hemofiltration and seventy hemofilters used for chronic maintenance hemofiltration were studied for the clearances of urea nitrogen and creatinine and sieving coefficients of albumin and electrolytes. Hemofilters were successfully reused in pump-assisted acute hemofiltration and chronic hemofiltration. In continuous arteriovenous hemofiltration, hemofilters could not be reused mainly because of clotting of fibers. The practice is safe, efficient and highly cost-saving.

Equipment Contamination↗
PubMed1987

IgA nephropathy associated with hepatitis B virus antigenemia.

The pathogenetic ability of hepatitis B virus (HBV) antigenemia to induce IgA nephropathy was examined in 10 patients with IgA nephropathy and HBV antigenemia. They had no previous history of liver diseases and their liver function tests were normal. All were positive for hepatitis + surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBcAg) with high titers, thereby indicating they were persistent carriers of HBV. Immunoperoxidase studies using monospecific polyclonal antibodies revealed HBcAg and HBsAg in the nuclei and cytoplasm of glomerular mesangial cells in 8 patients. These findings suggest immune complexes involving HBcAg and HBsAg may induce IgA nephropathy in persons who carry HBV.

Adult↗
PubMed1987

Pattern of glomerulonephritis in Hong Kong.

A retrospective analysis of all renal biopsies (961) performed in two regional hospitals in Hong Kong during 1977-1985 revealed that IgA nephropathy was the most frequently encountered glomerulopathy. Lipoid nephrosis (minimal change nephrotic syndrome) remained the commonest cause of nephrotic syndrome in children. The frequencies of mesangiocapillary glomerulonephritis, focal glomerulosclerosis, and idiopathic membranous nephropathy were lower than in other populations. Membranous nephropathy was frequently associated with hepatitis B virus antigenemia, especially in children. Other chronic infections did not have a significant pathogenetic role in glomerular diseases. Lupus nephritis was the commonest secondary glomerular disease in our study, and over seventy percent of the renal biopsies showed advanced pathologies with either diffuse proliferative glomerulonephritis or membranous nephropathy.

Adolescent↗
PubMed1987

Studies of lymphocyte subpopulations and immunoglobulin production in IgA nephropathy.

This work was undertaken to examine the immunoregulation of T lymphocytes in patients with IgA nephropathy. Fifty patients and thirty-seven control subjects were studied in an infection-free interval. T lymphocyte subpopulations were determined using OKT monoclonal antibodies against helper (OKT4) and suppressor (OKT8) T cell subsets. The proportions of T lymphocyte subpopulations did not differ between patients and controls. Patients with significant renal impairment demonstrated a reduced OKT4/T8 ratio (p less than 0.001) due to an absolute reduction of T helper cells (p less than 0.02) and an increase of T suppressor cells (p less than 0.001). Longitudinal studies performed in 13 patients revealed consistent findings during clinical quiescence. However, synpharyngitic macroscopic haematuria was associated with a rise in T4 positive cells and a simultaneous reduction of T8 positive cells; these changes reverted to pre-infection values when the infection subsided. Functional studies assessing T lymphocyte activities including in vitro immunoglobulin synthesis by cultured peripheral blood mononuclear cells, thymidine uptake by cultured lymphocytes and T lymphocytes activation with expression of interleukin-2 receptors were measured in unstimulated and mitogen stimulated cultures. No significant difference between patients with IgA nephropathy in clinical quiescence and the control subjects was demonstrated. Our results failed to support a shift in the immuno-regulatory T lymphocyte subpopulations during clinical quiescence but a more profound defect in immunoregulation may probably occur during clinical exacerbation.

Fluorescent Antibody Technique↗
PubMed1987

The clinico-pathologic features of hepatitis B virus-associated glomerulonephritis.

The frequency of hepatitis B surface antigen (HBsAg) was studied in the sera of 311 patients with various forms of primary glomerulonephritis and 43 patients with lupus nephritis. HBs antigenaemia was detected in 69 of the 311 patients (22 per cent) with primary glomerulonephritis and this prevalence of HBsAg carrier was significantly higher than that in the general population (p less than 0.001). These patients had no clinical or biochemical findings to suggest acute or chronic liver disease. A higher HBs antigenaemia carrier rate was not observed in patients with lupus nephritis. Three glomerulopathological entities, membranous nephropathy, IgA nephropathy, and mesangial proliferative glomerulonephritis, were found to be associated with a higher prevalence of HBs antigenaemia compared with the general population (p less than 0.001). Glomerular deposits of HBsAg and/or hepatitis core antigen (HBcAg) were detected in 41, 61, and 60 per cent of renal biopsy specimens from patients with membranous nephropathy, IgA nephropathy, and mesangial proliferative glomerulonephritis associated with persistent HBs antigenaemia respectively. During the mean study period of 40 months (range 12-180), 14 per cent of these patients with hepatitis-associated glomerulonephritis developed progressive renal failure, although none required maintenance dialysis. Our study suggests that hepatitis B virus antigenaemia may play a significant role in the development of specific forms of glomerulonephritis and that these hepatitis B virus-associated glomerulonephritides can run an indolent but relentless progressive clinical course.

Adolescent↗
PubMed1987

Is there a pathogenetic role of hepatitis B virus in lupus nephritis?

In view of the widely disputed frequency with which hepatitis B surface antigen (HBsAg) is found in the sera and kidney biopsy specimens of patients with systemic lupus erythematosus (SLE), serologic screening of HBsAg and immunofluorescence studies for HBsAg and hepatitis B core antigen in renal biopsy specimens were performed in 45 patients with SLE. Five of the 45 patients with SLE had HBs antigenemia, and the prevalence was not significantly different from that of the general population in Hong Kong. The renal biopsy findings of these five patients showed lupus nephritis in two and features suggestive of hepatitis-induced glomerulonephritis in three. Our findings do not support an increased prevalence of HBsAg in sera or kidney of patients with SLE, and hepatitis B virus is unlikely to have a pathogenetic role in SLE in areas where both SLE and HBs antigenemia are common.

Adolescent↗
PubMed1986

The clinical significance of proteinuria in patients with nonparasitic chyluria.

Five patients with heavy proteinuria and nonparasitic chyluria due to congenital abnormalities of the lymphatic system are described. Renal biopsies confirmed the clinical suspicion of an underlying glomerulonephritis. The coexistence of glomerulonephritis and chyluria in these patients was thought coincidental. Tests of value in detecting a concomitant glomerulonephritis in these patients with chyluria include urinary RBC morphology, quantitation of 24-hour urinary protein, and immunoelectrophoresis of serum and urinary proteins. Contrary to previous reports, the present study suggests that chyluria does not produce proteinuria of enough severity to cause hypoproteinemia.

Adult↗
PubMed1986

An overlapping syndrome of IgA nephropathy and lipoid nephrosis.

The authors studied eight cases of IgA nephropathy presenting with nephrotic syndrome. Renal biopsy revealed only mild mesangial proliferation or minor glomerular changes on light microscopic examination but typical features of IgA nephropathy on immunofluorescent and electron microscopic examination. A satisfactory response characterized by correction of hypoalbuminemia, clearance of proteinuria, and an increase of endogenous creatinine clearance occurred with corticosteroid therapy. These cases represent a variant of IgA nephropathy associated with a nephrotic syndrome that resembles lipoid nephrosis in its responsiveness to steroid.

Basement Membrane↗
PubMed1986

The clinical use of serum beta-2-microglobulin and fractional beta-2-microglobulin excretion in IgA nephropathy.

We measured serum beta-2-microglobulin (B2-m) and fractional beta-2-microglobulin excretion in 29 patients with IgA nephropathy. The mean serum B2-m in IgA nephropathy patients was significantly higher than that of healthy controls (p less than 0.025). The serum B2-m correlated well with serum creatinine and endogenous creatinine clearance (p less than 0.01). Patients with diffuse mesangial proliferation and glomerulosclerosis had a significantly higher level of B2-m than those with minor glomerular pathology (p less than 0.01). Patients with hypertension had significantly different levels of serum B2-m from normotensive patients (p less than 0.01). The mean fractional B2-m excretion in IgA nephropathy patients was significantly higher than that of healthy controls (p less than 0.001). Patients with moderate tubulo-interstitial involvement had significantly higher fractional B2-m excretion than those with mild tubulo-interstitial changes (p less than 0.01). Our study suggests that serum B2-m and fractional B2-m excretion may be useful indicators in the long-term prognosis of patients with IgA nephropathy.

Adolescent↗
PubMed1986

Corticosteroid therapy in IgA nephropathy with nephrotic syndrome: a long-term controlled trial.

A randomized prospective study of 34 patients with IgA nephropathy and nephrotic syndrome was conducted to determine the therapeutic value of corticosteroid therapy. The patients were divided into two groups: Group A, 17 patients receiving oral prednisolone/prednisone for four months; and Group B, 17 patients receiving no corticosteroid therapy and acting as controls. The groups are comparable in age of presentation, sex ratio, and duration of study. No difference in serum creatinine levels, creatinine clearance, serum IgA levels, severity of renal histopathological changes, incidence of hypertension or incidence of impaired renal function could be demonstrated but the Group A patients had significantly heavier proteinuria. During the mean study period of 38 months (range 12-106), no significant difference in serum creatinine levels and creatinine clearance was demonstrated between the two groups. Forty percent of the Group A patients developed complications related to steroid therapy. Despite the overall lack of therapeutic value in IgA nephropathy with nephrotic syndrome as reflected by change in renal function, corticosteroid treatment resulted in excellent remission of nephrotic syndrome in 80% of patients with mild glomerular histopathological changes. Our findings suggest that corticosteroid therapy is only beneficial to selected groups of patients with IgA nephropathy and nephrotic syndrome but its indiscriminate use should be discouraged.

Administration, Oral↗
PubMed1985

Nephrotic range proteinuria--a good predictive index of disease in IgA nephropathy?

A combined retrospective and prospective study of 86 patients with IgA nephropathy was conducted to determine whether the level of proteinuria was a good predictive index of progressive disease. The patients fell into three groups: Group A, 31 patients with proteinuria of less than 1 g/day, Group B, 31 patients with proteinuria of 1 to 3.5 g/day; and Group C, 24 patients with proteinuria of more than 3.5 g/day. The groups are comparable in age of presentation, sex ratio, and duration of study and showed no difference in serum creatinine levels, creatinine clearance, incidence of hypertension or incidence of impaired renal function. Compared with the patients in the other groups, those in Group C did not have increased incidence of progressive disease. Nevertheless, they have a higher incidence of nephrotic syndrome (p less than 0.001), a lower incidence of macroscopic haematuria (p less than 0.05), lower serum albumin (p less than 0.05) and heavier proteinuria (p less than 0.01). Severity of proteinuria had no significant correlation with the severity of renal histopathologic changes. Clinical observations divided the 24 patients with nephrotic range proteinuria into three well-defined groups with different prognoses. Six patients had progressive disease with decreasing proteinuria. Five of these remained hypertensive and their initial renal biopsy showed advanced pathologic changes. Thirteen patients had persistent proteinuria although the renal function remained unchanged. Three of these were treated with steroid but failed to respond, and their renal histopathologic changes were usually moderate. The remaining five patients showed good response to steroid treatment although two became steroid-dependent. Their renal histopathology showed mild alteration. Our findings suggest that severe proteinuria in IgA nephropathy does not inevitably indicate a poor prognosis.

Adolescent↗
PubMed1984

The vasorelaxant effect of (+/-)-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl-prostaglandin E2 (CL 115, 129) and its methyl ester (CL 115, 347) on the isolated ductus arteriosus preparation.

CL 115, 129 and its methyl ester, CL 115, 347, were studied for their vasorelaxant effects and compared to that of prostaglandin (PG) E2 and its methyl ester on isolated ductus arteriosus (DA) from fetal lambs and rabbits. CL 115, 129 and CL 115, 347 potently relaxed the oxygen-indomethacin constricted ductus in a concentration dependent manner. The threshold concentration was 1 X 10(-12)M and the estimated EC50's (M) were 6.9 X 10(-8) and 4.3 X 10(-8), respectively, for CL 115, 129 and CL 115, 347. Also confirmed was the vasorelaxant ability of PGE2. These studies indicate that the CL compounds possess potent vasorelaxant effects on the DA although less potent than PGE2 or its methyl ester.

Animals↗
PubMed1984

Effects of CL 115,347, (+/-)-15-deoxy-16-hydroxy-16-vinyl-PGE2 methyl ester, on cardiovascular responses and plasma catecholamines in pithed stroke-prone spontaneously hypertensive rats during sympathetic stimulation.

The effect of CL 115,347, a topically active antihypertensive PGE2 analog, and PGE2 on changes in blood pressure (BP), heart rate (HR) response and plasma epinephrine (E) and norepinephrine (NE) levels induced by stimulation of the sympathetic spinal cord outflow were studied in pithed stroke-prone spontaneously hypertensive rats (SHRSP). Surgical pithing significantly reduced plasma E but not NE levels suggesting that the sympathoadrenal medullary system differentially affects E and NE release. Sympathetic stimulation of the spinal cord of pithed SHRSP increased HR, BP, plasma E and NE levels. Topically applied CL 115,347 (0.001-0.2 mg/kg) dose-dependently decreased BP, while intravenously infused PGE2 (30 micrograms/kg/min) did not alter BP except for a brief initial drop. Topical application of CL 115,347 (0.1 mg/kg) also inhibited BP responses to sympathetic stimulation without effects on HR or plasma E or NE levels. Intravenous infusion of PGE2 (30 micrograms/kg/min) inhibited both BP and HR responses to spinal cord stimulation but did not alter plasma catecholamine levels. These studies in SHRSP suggest that CL 115,347 and PGE2 modulate cardiovascular responses mainly via postjunctional effects, but act differently on the cardiovascular elements, viz. CL 115,347 acts primarily on blood vessels while PGE2 acts on blood vessels and heart.

Animals↗
PubMed1984

Evidence for the lack of interaction between (+/-)-1-O-octadecyl-2-acetylglyceryl-3-phosphorylcholine and alpha-adrenoceptors in vivo and in vitro.

The interactions of (+/-)-1-O-octadecyl-2-acetylglyceryl-3-phosphorylcholine (octadecyl-AGPC) with alpha-adrenoceptors were studied in rat mesenteric artery, cat nictitating membrane and on the blood pressure of the cat and spontaneously hypertensive (SH) rat. Using a direct radioligand alpha-adrenoceptor binding assay in particulate fractions of rat mesenteric arteries, octadecyl-AGPC was found to be 5 X 10(7) and 75 times less potent than prazosin and noradrenaline (NA), respectively, in displacing (2,6-dimethoxyphenoxyethyl)-aminomethyl-1,4-benzodioxane ([3H]-WB 4101--a selective probe for the identification of alpha-adrenoceptors). In the cat, intravenous infusions of octadecyl-AGPC, which produce a hypotensive response, did not attenuate nictitating membrane contractions in vivo in response to intravenous injections of NA, adrenaline (Ad) or to electrical stimulation of the postganglionic fibres of the superior cervical ganglion. In these experiments, the pressor responses to NA or Ad were not affected by octadecyl-AGPC. Phentolamine, on the other hand, attenuated nictitating membrane contractions and blood pressure responses to Ad or NA. In the SH rat, octadecyl-AGPC decreased mean arterial blood pressure (MABP). After an intravenous dose of phentolamine which lowered MABP, the depressor response to octadecyl-AGPC was reduced. When MABP in the phentolamine-treated SH rat was restored to its initial level with an infusion of angiotensin II (AII), the depressor response to octadecyl-AGPC was restored to its original magnitude. The effectiveness of alpha-adrenoceptor blockade under these experimental conditions was monitored with intravenous NA and Ad. Thus, based on radioligand binding studies and pharmacological studies, it is concluded that octadecyl-AGPC lacks the ability to interact with alpha-adrenoceptors.

Angiotensin II↗
PubMed1984

A comparison of cardiac alpha-adrenoceptor number and affinity between aorta-coarcted hypertensive and normotensive rats.

Aorta-coarcted hypertensive rats (AHR) and sham-operated normotensive rats (SNR) were compared in order to assess the effect of elevated blood pressure (BP) on the concentration and affinity of cardiac adrenoceptors in these rats at different stages of hypertension. Body weight was significantly reduced, mean arterial blood pressure (MABP) and the ratio by ventricle/body weight (index of hypertropy) were significantly increased in coarcted rats at 2, 6 and 28 days after ligation of the abdominal aorta. Myocardial membranes prepared from hypertensive rats at various stages of hypertension contained the same concentration of cardiac alpha-adrenoceptors as compared to corresponding time-matched, sham-operated controls. In addition, the receptor affinity for the radioligand was similar between hypertensive rats and their respective controls. Thus, aorta-coarctation induced hypertension is not associated with any alterations in cardiac alpha-adrenoceptors, which is different from reports in other models of experimental hypertension.

Animals↗