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Biomedical subjects

J F Knight

Publications and source records attributed to J F Knight.

At least 37 records · Page 2Linked to original sources
PubMed2000

Daytime urinary incontinence in primary school children: a population-based survey.

OBJECTIVES: To determine the prevalence and severity of, and risk factors for, daytime urinary incontinence in children starting primary school. DESIGN AND SETTING: Population-based cross-sectional survey of new entrant primary school children in Sydney, Australia. METHODS: A random cluster sample of 2020 primary school children was surveyed by using a daytime incontinence questionnaire with known substantial repeatability (mean kappa = 0.70). RESULTS: The questionnaire was returned for 1419 (70%) children with a mean age of 5.9 years; 16.5% of children had experienced one or more episodes of wetting in the last 6 months (mild), 2.0% had wet twice or more per week (moderate), and 0.7% were wet every day (severe) (overall prevalence of 19.2%). On multivariate analysis, recent emotional stress (odds ratio 5.7), a history of daytime wetting along the paternal line (odds ratio 9.3), and a history of wetting among male siblings (odds ratio 5.3) were independent risk factors for moderate to severe daytime wetting. Expressed as population attributable risk, 59% and 28% of moderate-severe and mild daytime wetting, respectively, can be attributed to these 3 factors. Only 16% of families with affected children had sought medical help. CONCLUSIONS: Daytime urinary incontinence in the first year of primary school is more common than previously reported, and only a small proportion of affected children seek medical help. Emotional stress and family history are likely to be major causal factors.

Child↗
PubMed2000

Corticosteroid therapy in nephrotic syndrome: a meta-analysis of randomised controlled trials.

AIMS: To determine the benefits and toxicity of different corticosteroid regimes in preventing relapse in steroid responsive nephrotic syndrome. DESIGN: Meta-analysis of randomised controlled trials. SUBJECTS: Twelve trials involving 868 children aged 3 months to 18 years. MAIN OUTCOME MEASURE: Frequency of relapse. RESULTS: A meta-analysis of five trials, which compared two months of prednisone with three months or more in the first episode, showed that the longer duration significantly reduced the risk of relapse at 12-24 months (relative risk 0.73; 95% confidence interval 0.60 to 0.89) without an increase in adverse events. There was an inverse linear relation (relative risk 1.382 (SE 0.215) - 0.133 (SE 0.048) duration; r(2) = 0.66; p = 0.05) between the duration of treatment and risk of relapse. CONCLUSIONS: Children in their first episode of steroid responsive nephrotic syndrome should be treated with prednisone for at least three months, with an increase in benefit being shown for up to seven months of treatment.

Adolescent↗
PubMed2000

Does treatment of vesicoureteric reflux in childhood prevent end-stage renal disease attributable to reflux nephropathy?

OBJECTIVE: It is believed that end-stage renal disease (ESRD) attributable to reflux nephropathy is preventable by the active treatment of vesicoureteric reflux in childhood with long-term antibiotics and ureteric reimplantation surgery. We aimed to test this belief. METHODOLOGY: The Australia and New Zealand Dialysis and Transplant Registry of new patients 5 to 44 years of age treated for ESRD between 1971 and 1998, categorized by age and primary renal disease, was used to analyze the age-specific incidences of ESRD attributable to reflux nephropathy using a before-after study design. The early 1960s were regarded as the introduction period for the active treatment of childhood vesicoureteric reflux. A time-delay in treatment effect was expected. Patients with ESRD attributable to other causes were used as a comparative group. RESULTS: The incidence of ESRD attributable to reflux nephropathy and nonreflux nephropathy has increased. For reflux nephropathy, the rate of change was significantly associated with age, with a downward trend in incidence with decreasing age suggesting a minor treatment effect. This trend was no longer evident when adjustment was made for changing diagnostic practices. An opposite trend was observed for the nonreflux nephropathy group, who demonstrated an upward trend in incidence with decreasing age. CONCLUSIONS: Treatment of children with vesicoureteric reflux has not been accompanied by the hoped-for reduction in the incidence of ESRD attributable to reflux nephropathy. A randomized trial with a control (no-treatment) arm is required to appropriately assess the medical belief that long-term antibiotics and surgery improve the natural history of vesicoureteric reflux.

Adolescent↗
PubMed1999

Conserved T-cell receptor beta chain CDR3 sequences in IgA nephropathy biopsies.

BACKGROUND: We have previously reported that both alpha beta and gamma delta T cells are involved in the progression of IgA nephropathy (IgAN) to renal failure. To determine whether the T-cells seen in the interstitium represent a generalized inflammatory response or whether they are proliferating oligoclonally in response to a particular antigen, we analyzed the TCR Vbeta gene usage by T cells infiltrating renal biopsies from patients with IgAN. METHODS: Fourteen IgAN patients were divided by clinical criteria into stable and progressive groups (7 in each group). Reverse transcription-polymerase chain reaction (RT-PCR) and cloning were used to characterize the expression of TCR Vbeta families in renal biopsies and in peripheral blood lymphocytes. RESULTS: TCR Vbeta8 was significantly and preferentially expressed in most IgAN kidney biopsies compared with peripheral blood lymphocytes from both IgAN patients and healthy controls (P < 0.001). TCR Vbeta8 expression was more marked in progressive biopsies than in stable biopsies (P < 0.05). Spectratyping of Vbeta8 RT-PCR products from T cells infiltrating the kidney showed an intense spectratype band at the shortest range of amplified CDR3s in the renal biopsies of four patients. Analysis of nucleotide and deduced amino acid sequences of Vbeta8 PCR products derived from intense spectratype bands from these renal biopsies revealed a high concordance across the CDR3 region. A conserved amino acid (leucine) at the first position of the nongermline-encoded nucleotides and diversity (ND) junction of Vbeta8 was found at a frequency of 95% in multiple sequences obtained from the renal biopsies of all four patients examined. CONCLUSIONS: The preferential use of Vbeta8 with marked similarities in the CDR3 region by some renal infiltrating T cells suggests clonal expansion of T cells in the kidneys of some IgAN patients. Conserved amino acids in the TCR CDR3 hypervariable region may contribute to the recognition of a particular antigen or set of antigens.

Adult↗
PubMed1999

The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on postoperative renal function: a meta-analysis.

The aim of this systematic review was to assess the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on post-operative renal function. Eight randomized placebo-controlled double-blinded trials (n = 345) were identified from searches of MEDLINE, EMBASE and the Cochrane Controlled Trials Register databases. The summary effect size and 95% confidence intervals (95% CI) were calculated by a weighted mean difference analysis using a random-effects model. The NSAIDs (diclofenac, ketorolac, indomethacin, ibuprofen) were used for up to three-days after surgery. There were no reported cases of postoperative renal failure requiring dialysis. NSAIDs reduced creatinine clearance by 22 ml.min-1 (95% CI: 7 to 37), sodium output by 54 mmol.day-1 (95% CI: 5 to 103) and potassium output by 38 mmol.day-1 (95% CI: 19 to 56) on Day 1 but not on Day 2. Serum creatinine increased on Day 2 by 15 mumol.l-1 (95% CI: 2 to 28). Urine volume did not change significantly at any time. There was therefore a clinically unimportant transient reduction in renal function. NSAIDs should not be withheld from patients with normal preoperative renal function because of concerns about postoperative renal impairment.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Nutritional intervention and growth in children with chronic renal failure.

OBJECTIVE: To assess whether improving energy intake by tube feeding could prevent growth failure and improve growth rates in children with congenital renal failure. DESIGN: Prospective descriptive study. SETTING: Renal Units, Royal Alexandra Hospital for Children, and Westmead Hospitals. PATIENTS: All children with advanced chronic renal disease (glomerular filtration rate < 30 mL/min/1.73 m2) between 1992 and 1994. INTERVENTION: Tube feeding was commenced if height or weight standard deviation score (SDS) was below the normal range (> -2 SDS) or when height SDS was decreasing and oral intake was not meeting energy requirements. Energy requirements were calculated for median weight for chronological age and sex to provide for catch-up growth. MAIN OUTCOME MEASURES: Growth rate was measured by comparing height and weight SDS at the beginning and end of the study period. Normal growth rate is defined as no change in SDS over time, whereas catch-up growth is defined as an increase in SDS over time. RESULTS: Seven children, mean age 0.6 +/- 0.7 years, with advanced renal failure (mean glomerular filtration rate = 17 mL/min/1.73 m2) caused by congenital renal hypoplasia/dysplasia were studied. All subjects were eventually tube fed for a mean time of 18. 6 +/- 4.5 months. There was no significant change in height SDS (-0. 9 to -1.1) or weight SDS (-0.4 to -0.2). CONCLUSION: Optimizing nutritional intake by tube feeding children with advanced chronic renal failure from an early age resulted in no decline in growth rate; however, catch-up growth was not achieved.

Body Height↗
PubMed1998

Symptomatic urinary tract infection in preschool Australian children.

OBJECTIVE: To describe the demographic and clinical features, short-term outcomes, microbiology and renal tract abnormalities of a cohort of young Australian children with symptomatic urinary tract infection. METHODOLOGY: A total of 304 children < 5 years with their first documented symptomatic urinary tract infection who presented consecutively to the Emergency Department of a paediatric hospital between March 1993 and December 1994 and without a known predisposing cause were identified and details of their acute illness were recorded. Renal tract sonography, micturating cystourethrography and Tc-99 m dimercaptosuccinic acid scintigraphy (DMSA) were routinely performed. RESULTS: Of those who presented with urinary tract infection, 169 were boys and 135 girls; 64% were less than 1 year of age. For children from the local community, the cumulative incidence of urinary tract infection within the first 5 years of life was estimated to be 1.9% for boys and 1.8% for girls. There were no significant differences in illness characteristics according to mode of referral or geographical locality. Presenting symptoms were generally nonspecific and not referrable to the urinary tract. There were no deaths. One per cent of children required ventilatory support, and bacteraemia occurred in 6%, all of whom were under 6 months of age. E. coli was the causal organism in 84%, and a high in vitro resistance to ampicillin/ amoxycillin (54%) was demonstrated by the pathogens isolated. Bacteriuria was eradicated in 99% with antimicrobial treatment. In this setting, the sensitivities of dipstick urinalysis (leucocyte esterase+/-nitrites) and pyuria on microscopy (>10 x 10(6) white cells L(-1)) were 85%. Abnormal DMSA scintigraphy was detected in 39%, vesicoureteric reflux in 28%, and obstructive uropathy in 1%. CONCLUSIONS: This study provides current and local data on a large sample of children <5 years with urinary tract infection, which are useful to clinicians who manage children at risk of the condition.

Acute Disease↗
PubMed1998

Variability in the interpretation of dimercaptosuccinic acid scintigraphy after urinary tract infection in children.

UNLABELLED: Technetium-99m-dimercaptosuccinic acid (DMSA) scintigraphy is a frequently used diagnostic test in pediatric practice to assess the presence and severity of renal damage. Most commonly it is performed after urinary tract infection. The aim of this study was to investigate the variability in the interpretation of DMSA scans by pediatric nuclear medicine physicians in this clinical setting. METHODS: We selected all 441 scans from children with first-time urinary tract infection who presented between 1993 and 1995 to a pediatric casualty department and who are participants in a prospective cohort study. Two hundred and ninety-four scans were performed at a median time of 7 days after diagnosis, and 147 scans were from children who were free from further infection over a 1-yr follow-up period. Two experienced nuclear medicine physicians independently interpreted the 441 scans according to whether renal damage was present or absent and using the modified 4-level grading system for DMSA abnormality of Goldraich. Apart from being informed that urinary tract infection was the indication for DMSA scintigraphy, no other clinical information was given to the nuclear medicine physicians. The indices of variability used were the percentage of agreement and the kappa statistic. For the grading scale used, both measures were weighted with integers representing the number of categories from perfect agreement. Disagreement was analyzed for children, kidneys and kidney zones. RESULTS: There was agreement in 86% (kappa = 69%) for the normal-abnormal DMSA scan dichotomy, and the weighted agreement was 94% (weighted kappa = 82%) for the grading of abnormality. Disagreement of DMSA scan interpretation of > or =2 grades was present in three cases (0.7%). The same high level of agreement was present for patient, kidney and kidney zone comparisons. Agreement was not influenced by age or timing of scintigraphy after urinary tract infection. CONCLUSION: Two experienced nuclear medicine physicians showed good agreement in the interpretation of DMSA scintigraphy in children after urinary tract infection and using the grading system of Goldraich.

Child↗
PubMed1997

Variation in the diagnosis of vesicoureteric reflux using micturating cystourethrography.

Variability in the interpretation of micturating cystourethrography by paediatric radiologists for the diagnosis of vesicoureteric reflux in children was evaluated. All 265 micturating cystourethrograms (MCUs) that were available from 304 consecutive children aged 0.5-61 months-who were investigated after their first urine infection between 1993 and 1995 as part of a prospective cohort study-were selected for interpretation. Three experienced paediatric radiologists from the same department independently interpreted the MCUs according to the grading system of the International Reflux Study in Children, from grades 0 to V, with the presence of intrarenal reflux also noted. Apart from being informed that urine infection was the indication for the MCU, no other clinical information was given to the radiologists. The indices of variability used were the percentage of agreement and the kappa statistic, expressed as a percentage. Both measures were weighted with integers representing the number of categories from perfect agreement. Disagreement was analysed for children and kidneys. For the diagnosis of vesicoureteric reflux in individual patients, including grade, the percentage of agreement was 96%-97% (kappa 90%-91%) and the weighted percentage of agreement was 96%-98% (weighted kappa 93%-94%). The same high level of agreement was present for individual kidneys, with a percentage of agreement of 97%-98% (kappa 89%-92%) and a weighted percentage of agreement of 98%-99% (kappa 94%-95%). There was near perfect agreement in the interpretation of radiological micturating cystourethrography among three experienced paediatric radiologists for the diagnosis and grade of vesicoureteric reflux. Any variations in the medical care of children suspected of having vesicoureteric reflux are not explained by differences in the reporting of this diagnostic test.

Child↗
PubMed1997

Trends in the health burden due to urinary tract infection in children in Australia.

OBJECTIVE: To estimate the health burden of urinary tract infection in children less than 15 years of age in Australia and to ascertain whether any significant change has occurred during the past decade. METHODOLOGY: The number of children less than 15 years of age who were admitted in New South Wales for urinary tract infection between 1981 and 1994 was ascertained from the Department of Health, and age and sex specific incidence rates were calculated using Australian Bureau of Statistics population data. Costs for inpatient care were calculated using the cost weights from Australia National Disease Related Groups Version 3 for urinary tract infection (DRG 577). The frequency of the four most commonly requested renal tract imaging procedures in children following urinary tract infection and which qualified for Medicare reimbursement were obtained from the Health Insurance Commission for 1984-1994: micturating cystourethrography, intravenous urography, renal ultrasonography, and nuclear medicine renal studies. RESULTS: There were 1203 children who were admitted with urinary tract infection in New South Wales in 1994, at an estimated cost of $A1.6 million. Since 1981, the age standardized annual incidence of urinary tract infection requiring hospitalization has increased from 0.5 to 0.9 per 1000 children, largely because of an increase in the number of young children admitted (from 0.6 to 2.0 per 1000 children less than 5 years of age). In 1994, 46,230 non-inpatient renal imaging procedures were undertaken in children under 15 years of age at a cost of $A5.3 million. CONCLUSIONS: Urinary tract infection is an important and increasing health problem for Australian children, particularly for preschool children. Whether this represents a true increase in the incidence of urinary tract infection or improved diagnosis and more intensive management is not possible to establish with this study design. Prospective population based studies are required to assess more completely the frequency with which urinary tract infection occurs in children and any changes that may be occurring.

Adolescent↗
PubMed1997

Vesicoureteric reflux and timing of micturating cystourethrography after urinary tract infection.

OBJECTIVE: To test the medical belief that the micturating cystourethrogram (MCU) be deferred four to six weeks after acute symptomatic urinary tract infection (UTI) because of the risk of falsely detecting vesicoureteric reflux if performed earlier. STUDY DESIGN: A cross sectional analytic study of preschool children with first time symptomatic UTI. RESULTS: Of the 284 eligible children, 272 (95.8%) had MCU at a median time of 29 days after diagnosis (range 5 to 167 days). Vesicoureteric reflux was present in 77 children (28.3%). Beyond one week after diagnosis (270 children) the proportion and severity of vesicoureteric reflux detected was not associated with the timing of the MCU. Before one week, both children tested had vesicoureteric reflux. CONCLUSIONS: The presence and grade of vesicoureteric reflux is not influenced by the timing of the MCU one week after acute symptomatic UTI. There may be an association between the MCU and the presence of vesicoureteric reflux for children tested within one week after UTI. The MCU need not be deferred for four to six weeks after UTI.

Child, Preschool↗
PubMed1996

Communication breakdown: a preventable cause of acute renal failure in a newborn infant.

A three-week-old boy had life-threatening renal failure which was successfully treated by salbutamol and sodium bicarbonate infusion, rectal resonium and a left percutaneous nephrostomy. Ultrasonography of this child at 19 weeks' gestation had shown a treatable renal tract abnormality (bilateral hydronephrosis). No arrangements had been made for follow-up.

Acute Kidney Injury↗
PubMed1996

Neonatal Bartter syndrome--use of indomethacin in the newborn period and prevention of growth failure.

Neonatal Bartter syndrome differs from the classical Bartter syndrome in the occurrence of antenatal presentation with polyhydramnios. Nephrocalcinosis and severe growth retardation are common sequelae. Indomethacin has been reported to improve linear growth, but its use in the early newborn period has been infrequently described. In this paper we report normal growth and development and the absence of nephrocalcinosis in an infant now aged 19 months with neonatal Bartter syndrome treated from day 3 of life with indomethacin. With early diagnosis and treatment with indomethacin plus adequate water, calories, and sodium, normal growth can be achieved and nephrocalcinosis may be prevented in children with neonatal Bartter syndrome.

Bartter Syndrome↗
PubMed1996

Effect of circumcision on incidence of urinary tract infection in preschool boys.

OBJECTIVE: To determine whether circumcision decreases the risk of symptomatic urinary tract infection (UTI) in boys less than 5 years of age. STUDY DESIGN: A case-control study (1993 to 1995) in the setting of a large ambulatory pediatric service. Case subjects and control subjects were drawn from the same population. One hundred forty-four boys less than 5 years of age (median age, 5.8 months) who had a microbiologically proven symptomatic UTI (case subjects), were compared with 742 boys (median age, 21.0 months) who did not have a UTI (control subjects). The proportion of case and control subjects who were circumcised in each group was compared with the use of the chi-square test, with the strength of association between circumcision and UTI expressed in terms of an odds ratio. To determine whether age was a confounder or an effect-modifier, we stratified the groups by age (< 1 year; > or = 1 year) and analyzed by the method of Mantel-Haenszel. RESULTS: Of the 144 preschool boys with UTI, 2 (1.4%) were circumcised, compared with 47 (6.3%) of the 742 control subjects (chi-square value = 5.6; p = 0.02; odds ratio, 0.21; 95% confidence intervals, 0.06 to 0.76). There was no evidence that age was a confounder or modified the protective effect of circumcision on the development of UTI (Mantel-Haenszel chi-square value = 6.0; p = 0.01; combined odds ratio, 0.18; 95% confidence intervals, 0.05 to 0.71; Breslow-Day test of homogeneity chi-square value = 0.6; p = 0.4). CONCLUSIONS: Circumcision decreases the risk of symptomatic UTI in preschool boys. The protective effect is independent of age.

Age Distribution↗
PubMed1995

Infiltration of the kidney by alpha beta and gamma delta T cells: effect on progression in IgA nephropathy.

We have studied renal biopsies from three groups of patients to determine if alpha beta T cells or gamma delta T cells are present, and whether their presence is correlated with disease progression in IgA nephropathy (IgAN). Group one comprised thin basement membrane disease biopsies (non-immunological control, N = 7); group two were patients with IgAN and stable renal function one year following biopsy (stable, N = 7); and group three were IgAN patients with rapidly declining renal function after one year (progressive, N = 7). Immunohistochemical staining using monoclonal antibodies (CD3, TcR beta, TcR delta) and molecular studies utilizing polymerase chain reaction amplification of cDNA transcribed from biopsy RNA, with primers specific for either the alpha beta TcR or gamma delta TcR, were undertaken. On immunohistochemistry a significant increase in CD3 + cells in progressive biopsies was seen (vs. control P = 0.002, vs. stable P = 0.002). The progressive biopsies infiltrate consisted of both alpha beta TcR (vs. control P = 0.001, vs. stable P = 0.003) and gamma delta TcR cells (vs. control P = 0.01). The RNA study demonstrated an increase in TcR C alpha transcription in the progressive (vs. control P = 0.003) biopsies. Increased TcR C delta transcription was seen in the progressive group (vs. control P = 0.01, vs. stable P = 0.02). We confirm that the presence of lymphocytes in IgAN biopsies predicts progressive disease. While alpha beta T cells are found in both stable and progressive disease, the presence of gamma delta T cells is only associated with progressive IgAN.

Adult↗