Search PubMed⌕ Search

Biomedical subjects

K T Woo

Publications and source records attributed to K T Woo.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1989

IgA nephritis: a review of the pathogenetic mechanisms and the rationale for therapy.

Various pathogenetic mechanisms are involved in IgA nephritis: immunological; platelet, coagulation and vascular injury; mesangial cell proliferation and contractility; hypertension; glomerular hyperperfusion and tubulo-interstitial injury. It is now possible to identify the subgroup of patients with IgA nephritis who have adverse prognostic features and may develop progressive glomerular scarring with renal failure. These features are proteinuria greater than 1 gm/day, non-selective proteinuria, glomerulosclerosis, hypertension, crescents and medial hyperplasia of blood vessels on renal biopsy. Controlled trials involving cyclophosphamide, anti-platelet agent (dipyridamole) and low dose warfarin; prednisolone; angiotensin converting enzyme inhibitors and eicosapentanoic acid (fish oil) appear promising. Currently, patients with bad prognostic indices in the Department are offered entry into an ongoing controlled trial of dipyridamole and low dose (anti-thrombotic dose) warfarin. Those patients with nephrotic syndrome especially with selective proteinuria are treated with a course of prednisolone and failing that, cyclophosphamide. It is important to maintain adequate blood pressure control among hypertensive patients as uncontrolled hypertension can lead to accelerated renal failure. With the onset of even mild renal impairment, dietary protein restriction should be recommended as this will help to decrease the rate of renal deterioration due to glomerular hyperfusion.

Blood Platelets↗
PubMed1988

Anti-vascular endothelial cell antibodies in patients with IgA nephropathy: frequency and clinical significance.

This study examined the frequency of anti-vascular endothelial cell (VEC) antibodies (Ab) in 72 patients with IgA nephropathy (IgAN), and their possible relationship to clinical and histological parameters of the disease. An enzyme immunoassay was developed to measure the binding of sera to endothelial cells grown to a confluent monolayer. Thirty-two percent of IgAN patients had serum anti-VEC activity as compared to 4% of controls (P = 0.004) and 9% of patients with other primary glomerulonephritis (P = 0.017). This was shown to be due to anti-HLA class I Abs in 6 of the 23 IgAN patients, and in the 1 control positive for anti-VEC activity. Hence 17 IgAN patients had anti-VEC Abs, predominantly of the IgA subclass. Stimulation of the endothelial cells with interferon-gamma and interleukin 1 did not increase the binding of these Abs. There was no correlation with circulating immune complex (IC) levels, and removal of ICs in positive sera by ultracentrifugation did not decrease anti-VEC binding. Significant correlations were found between anti-VEC Abs and proteinuria greater than 1 g/day (P = 0.044), as well as IgA anti-VEC Abs and C3 or IgA deposition in renal arterioles (P = 0.048). These IgA Abs may be an important marker of pathogenetic activity in IgAN.

Adolescent↗
PubMed1988

Hypertension in IgA nephropathy.

Among 151 patients with IgA nephritis, 18/151 (12%) had hypertension at presentation and 50/151 (33%) were hypertensive after an interval of 65 +/- 40 (Mean +/- SD) months. Hypertensive patients (n = 50) had a higher incidence of glomerulosclerosis, medial hypertrophy of blood vessels, tubular atrophy, poorly selective proteinuria and extension of immunodeposits to peripheral capillary walls compared to normotensive patients (n = 101). Chronic renal failure occurred more commonly among hypertensives compared to normotensive patients (42%) versus 14%. However, the time taken for patients to reach renal impairment or end stage renal failure was not significantly different. The cumulative renal survival for the hypertensive group was 78% after 8 years compared to 91% in the normotensive group (p less than 0.05). In the second part of the study, patients who were hypertensive at presentation (n = 18) were compared with those who developed hypertension on follow up (n = 32). Apart from a shorter duration of follow up for patients with hypertension and a higher incidence of glomerulosclerosis, there were no significant differences in their clinical presentation, laboratory indices or other histological parameters. The incidence of chronic renal failure and the time taken to reach end stage renal failure were not different. Uncontrolled hypertension was an important cause for rapid deterioration to end stage renal failure within 3 years, compared to 8 years when hypertension was controlled.

Adult↗
PubMed1988

Controlled therapeutic trial of IgA nephritis with follow-up renal biopsies.

Forty-eight patients with IgA nephritis entered a 3 year controlled prospective trial using a combination regimen of cyclophosphamide for 6 months and dipyridamole and low dose warfarin for 36 months. Those in the treatment group (n = 27) had stable renal function and a significant decrease in proteinuria (p less than 0.01) but in the controlled group (n = 21) there was a significant fall in creatinine clearance (p less than 0.01) and rise in serum creatinine (p less than 0.02) with no change in proteinuria. The data suggested that the above treatment resulted in a significant reduction of proteinuria and more stable renal function. Eleven patients in the treatment group and 10 patients in the controlled group had repeat renal biopsies after the trial. Eight parameters were used in the evaluation of the renal biopsies: mesangial hypercellularity, crescents, tuft adhesion, segmental sclerosis, global sclerosis, tubular atrophy, interstitial fibrosis and vascular sclerosis. Each lesion was graded from 0 to 3 and a total scoring system used for evaluation of histological severity. In the treatment group there was no significant histological deterioration but in the controlled group there was progressive histological deterioration. Mean total histological score was 3.7 +/- 2.6 before the trial and 6.5 +/- 3.1 after the trial (p less than 0.05). This histological progression appeared to run parallel with the clinical course.

Biopsy, Needle↗
PubMed1987

Detection of bovine serum albumin in the circulating IgA immune complexes of patients with IgA nephropathy.

Alimentary antigenic challenge has been postulated to have a role in the genesis of IgA circulating immune complexes (CIC), resulting in mesangial IgA disease. In this study, we examined the relationship between bovine serum albumin (BSA) and IgA CIC in patients with IgA nephropathy. Of the 47 patients studied, elevated IgA CIC levels were found in 32% by the F(ab')2 anti-C3 and Raji cell enzyme immunoassays (EIA). Elevated IgA anti-BSA antibody levels were found in 9 patients, and there was a positive correlation between these levels and IgA CIC as measured in the Raji cell EIA (R = 0.60, P less than 0.001). In 4 patients with elevation of both IgA CIC and IgA anti-BSA antibody levels, solubilization experiments were done to demonstrate the presence of BSA antigen in the IgA CIC. Using the Raji cell EIA, the IgA CIC levels decreased significantly after preincubating the sera with serial concentrations of excess BSA. No corresponding effect was seen with human serum albumin used as control. Hence, BSA may be the antigenic stimulus in the formation of IgA CIC in selected patients with IgA nephropathy. The pathogenic capacity of these IgA-BSA CIC remains to be determined.

Adolescent↗
PubMed1987

Hemofiltration.

Explore the source record for details and available documents.

Acute Kidney Injury↗
PubMed1987

Effects of triple therapy on the progression of mesangial proliferative glomerulonephritis.

Fifty-two pairs of patients with idiopathic diffuse mesangial proliferative glomerulonephritis entered a controlled 3-year prospective trial of a combination regimen of cyclophosphamide, dipyridamole and warfarin. In the treatment group proteinuria decreased significantly (p less than 0.01) and renal function remained stable, but in the control group there was no change in proteinuria and creatinine clearance (Ccr) decreased significantly (p less than 0.01). The time patients with renal impairment in the control group and those in the treatment group took to reach end stage renal failure was significantly different (6.1 years versus 8.9 years, p less than 0.02). Among the patients with IgA nephritis, those in the treatment group (n = 27) had stable renal function and a significant decrease in proteinuria (p less than 0.01) but in the control group (n = 21) there was a significant fall in Ccr (p less than 0.01) and rise in serum creatinine (p less than 0.02) with no change in proteinuria. Among 23 pairs of patients in the study who were matched for renal function and degree of glomerulosclerosis, those in the treatment group had stable renal function and decrease in proteinuria (p less than 0.01) whereas those in the control group had decreased Ccr (p less than 0.01) but no change in proteinuria.

Adult↗
PubMed1986

Protein selectivity in IgA nephropathy.

The protein selectivity index was measured in 68 patients (53 males, 15 females) with proteinuria due to IgA nephropathy to determine whether it bore any relationship to other clinical and pathological features of known prognostic significance. The mean age of the patients was 25 +/- 8 years with a follow-up period of 42 +/- 35 months. Forty-six presented with asymptomatic haematuria and proteinuria, 17 with macroscopic haematuria and 5 with the nephrotic syndrome. Twenty-three (34%) patients had selective proteinuria and 45 (66%) had non-selective proteinuria. Patients with non-selective proteinuria had more glomerulosclerosis (29% +/- 20 vs. 16% +/- 20, p less than 0.02), higher serum creatinine (1.47 mg/dl +/- 0.70 vs. 1.17 mg/dl +/- 0.33, p less than 0.02), lower creatinine clearance (79 ml/min +/- 28 vs. 95 ml/min +/- 25, p less than 0.02), and higher incidence of hypertension (chi 2 = 3.84, p less than 0.05) when compared to those with selective proteinuria. The protein selectivity was measured at the end of the study. Of the 5 patients with the nephrotic syndrome, 1 had poorly selective proteinuria and failed to remit and 4 had highly selective proteinuria who either remitted spontaneously (1 patient) or with treatment (3 patients). The results suggest that patients with IgA nephropathy and poorly selective proteinuria are more likely to have other features indicating a poor prognosis such as glomerulosclerosis, renal impairment and hypertension.

Adult↗
PubMed1986

Glomerulonephritis in Singapore: an overview.

The pattern of glomerulonephritis (GN) consisting of 1057 renal biopsies is presented. Primary GN accounted for 91% and secondary GN 9% of which the commonest is lupus nephritis. Asymptomatic haematuria and proteinuria was the commonest mode of presentation (41%), gross haematuria 9%, nephrotic syndrome 29% while 5.5% presented with renal impairment and 4.3% with hypertension. Mesangial proliferative GN is the commonest histopathological lesion forming 66% of all primary GN. Minimal Lesion, Focal Global Sclerosis and Focal Segmental Glomerulosclerosis accounted for 7% each. Membranous GN was uncommon (3%) while Mesangiocapillary GN, Diffuse Endocapillary GN and Crescentic GN were even rarer. If the presenting feature was asymptomatic haematuria and proteinuria the likely diagnosis was IgA nephritis, and, if nephrotic syndrome it was likely to be Idiopathic Mesangial Proliferative GN but with negative staining on immunofluorescence. The course and prognosis of the various forms of GN are next discussed. Nephrotic syndrome with Minimal Lesion has an excellent prognosis while Crescenteric GN usually carries a grim prognosis. Finally, factors affecting the progression of IgA nephritis, the commonest form of GN occurring in Singapore are examined. Patients who developed renal failure ran two different courses; one was a slowly progressive course over an average of 7.7 years before reaching end stage renal failure (ESRF), while the other was a more rapid decline to ESRF within an average of 3.3 years where severe uncontrolled hypertension seemed to be the major adverse factor. 9% had renal impairment at the end of a follow up of 50 + 1/2 - 34 months while 5% progressed to ESRF. The cumulative renal survival was 91% after 6 years with no further loss up to 14 years. Unfavourable long term prognostic indices were proteinuria of more than 2 gms, hypertension, crescents on renal biopsy, severe segmental sclerosis and medial hypertrophy of blood vessels.

Adolescent↗
PubMed1986

Renal tubular acidosis.

The clinical features and biochemical profile of 10 patients with Renal Tubular Acidosis (RTA) were described. The commonest mode of presentation was muscular weakness due to severe hypokalaemia in 5 patients while the other 5 presented with renal colic, haematuria or passage of gravel. Nine patients had nephrocalcinosis on X-rays and one had rickets. All the patients had Type I RTA, 2 of whom presenting initially with Incomplete Type I RTA which progressed to Complete Type I RTA. Two other patients had associated features of proximal tubular involvement evidenced by hypophosphatemia, hypouricemia, hyperphosphaturia, aminoaciduria and glycosuria. Six of the 10 patients had secondary RTA: 2 associated with medullary sponge kidneys, 2 with gout, 1 with idiopathic hypercalciuria and hyperuricosuria and the remaining patient with systemic lupus erythematosus.

Acidosis, Renal Tubular↗
PubMed1986

Triamterene-induced crystalluria and cylinduria: clinical and experimental studies.

We examined the occurrence of crystals and casts in the urine of healthy subjects after administration of triamterene and the site of crystal formation in experimental animals. Twenty out of twenty healthy subjects had abundant triamterene crystals and casts in acid urine after receiving a single 100 mg dose. Casts were present in the urine from 2-11 hours after administration of the diuretic. Cast formation occurred in acidic urine and was prevented by alkalinization of the urine with potassium citrate. Animal studies showed that crystallization and cast formation occurred in the medullary and papillary collecting ducts of the rat kidney. These findings provide a possible explanation for the reported nephrotoxicity of triamterene, particularly when given to patients who are receiving non-steroidal anti-inflammatory agents.

Adult↗
PubMed1986

The natural history of IgA nephritis in Singapore.

The clinical and histological features of 151 patient with IgA nephritis were analyzed to determine the prognostic features of the disease. The mean duration of follow up examinations was 50 +/- 34 months (range 6 to 168 months). The majority of the patients were young males and showed no signs of IgA nephritis. The disease was detected by routine screening before induction into national service. The plot of the reciprocals of serum creatinine against time in the patients with progressive disease showed that the patients ran two different courses when they developed renal impairment; one was a slow progressive course over an average of 7.7 years before reaching end stage renal failure (ESRF), while the other was a more rapid decline to ESRF within an average of 3.3 years in which severe uncontrolled hypertension seemed to be the major adverse factor. Hypertension was present in 23% of patients. Nine percent had renal impairment at the end of the follow up period while 5% progressed to ESRF. The cumulative renal survival was 91% after 6 years with no further development of renal failure up to 14 years. Unfavorable long term prognostic indices were proteinuria of more than 2 gm, hypertension and presence of crescents on renal biopsy.

Atrophy↗