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Biomedical subjects

K L Lynn

Publications and source records attributed to K L Lynn.

At least 19 recordsLinked to original sources
PubMed2004

Diagnosis of aspergillus peritonitis in a renal dialysis patient by PCR and galactomannan detection.

This report describes the use of the polymerase chain reaction (PCR) and galactomannan detection to detect aspergillus in the continuous ambulatory peritoneal dialysis (CAPD) fluid and blood of a patient with multiple myeloma on CAPD and immunosuppressive treatment. Diagnosis of aspergillosis was initially made by conventional culture of CAPD fluid, but the PCR and galactomannan assays also detected aspergillus DNA and antigen in the blood, respectively. This suggests that the PCR and galactomannan assays, previously suggested as useful in the management of invasive fungal infections in neutropenic haematological patients, may be suitable for application to a broad range of clinical situations and sample types.

Aspergillosis↗
PubMed2001

Autonomic dysfunction and ambulatory blood pressure in renal transplant recipients.

BACKGROUND: Abnormal circadian blood pressure (BP) rhythm (nondipping) and autonomic dysfunction are both common in end-stage renal disease (ESRD). It is not known whether these abnormalities are related or if they are associated with greater left ventricular hypertrophy. METHODS: Nineteen renal transplantation (RT) recipients, aged 22-67 years, who were transplanted at least 12 months (1-29 years) previously, were studied with 24-hr ambulatory blood pressure monitoring (ABPM). Autonomic function was tested by automated analysis of heart rate variations and echocardiography was used to estimate left ventricular mass index (LVMI). RESULTS: Thirteen patients (68%) were nondippers. Although seven (37%) patients had significant parasympathetic dysfunction, this was not related to dipper status. Neither abnormality showed a tendency to diminish with time after RT. Systolic hypertension, diagnosed by ABPM, occurred in 5% of patients during the awake period and in 52% during sleep, whereas diastolic hypertension occurred in 47% when awake and in 63% when asleep. Awake systolic BP was the strongest predictor of LVMI (r=0.7, P<0.001), and was considerably better than systolic BPs recorded at the clinic (r=0.48, P<0.05). CONCLUSIONS: Nondipping is common after RT but is not related to the degree of autonomic dysfunction. These findings suggest that autonomic dysfunction is not a major contributor to nondipping in ESRD. In RT patients, ABPM is a more sensitive measure of hypertension and a stronger predictor of LVMI than clinic BP.

Adolescent↗
PubMed2001

A Comparative Study of Blood Pressure Control with Short In-Center versus Long Home Hemodialysis.

We conducted a randomized crossover trial to establish, within patients, whether long-slow hemodialysis (HD) was associated with better blood pressure (BP) control than standard HD. Nine home HD patients, not on antihypertensive drugs, were dialyzed to the same eKt/V(urea) and target weights for 6-8 h (LD) at home and for 3.5-4.5 h (SD) in the dialysis center 3 times weekly in randomized sequence, with each phase lasting 8 weeks. Ambulatory BP, bioimpedance, neurohormones and autonomic function were measured in each phase. Pre- and postdialysis systolic, ambulatory systolic and diastolic BP were all higher with SD than with LD and intradialysis hypotension was more common. Weight, ECF volume and neurohormones did not differ between treatments. Muscle sympathetic activity was increased in both phases and cardiac sympathetic activity tended higher during SD. These findings suggest that additional factors to ECF volume may contribute to the superior BP control produced by long-slow HD.

Adult↗
PubMed2001

Hypotensive and natriuretic actions of adrenomedullin in subjects with chronic renal impairment.

Plasma levels of adrenomedullin are increased in chronic renal failure. The significance of this finding is uncertain, because the biological effects of adrenomedullin in renal impairment are unknown. Therefore, we studied the effects of adrenomedullin infusion in subjects with chronic renal impairment. Eight males with IgA nephropathy and plasma creatinine of 0.19+/-0.03 mmol/L (mean+/-SEM) were studied in a vehicle-controlled crossover design. Each subject was studied twice; subjects were administered either adrenomedullin at a low dose and then a high dose (2.9 and 5.8 pmol/kg per minute, respectively, for 2 hours each) or a 4-hour vehicle control (Hemaccel), in random order, on day 4 of controlled metabolic diets. Adrenomedullin infusion achieved plasma adrenomedullin concentrations in the pathophysiological range after the low (31.2+/-5.1 pmol/L) and high (47.4+/-4.3 pmol/L) dose, and plasma cAMP was increased. Compared with vehicle control, high-dose adrenomedullin increased peak heart rate (+21.7+/-3.3 bpm, P<0.01) and cardiac output (+2.9+/-0.2 L/min, P<0.01) and lowered both systolic and diastolic blood pressures by >10 mm Hg (P<0.05). Plasma renin activity, angiotensin II, and norepinephrine increased by up to 50% above baseline levels (P<0.05 for all), whereas aldosterone and epinephrine were unchanged. Urinary volume and sodium excretion increased significantly (P<0.05) with low-dose adrenomedullin, whereas creatinine clearance was stable, and proteinuria tended to decrease. In subjects with chronic renal impairment due to IgA nephropathy, adrenomedullin infusion lowered blood pressure, stimulated sympathetic activity and renin release, and caused diuresis and natriuresis. Adrenomedullin may have a role in modulating blood pressure and kidney function in renal disease.

Adrenomedullin↗
PubMed2001

Cost-benefit analysis and prediction of 24-hour proteinuria from the spot urine protein-creatinine ratio.

AIM: A prospective cross-sectional study was performed on 170 patients with various glomerular diseases to study the accuracy of predicting 24-hour proteinuria from the spot urine protein-creatinine ratio (Up/Uc). A cost-benefit analysis was performed for the New Zealand health economic system to obtain the best cut-off values for proteinuria. SUBJECTS, METHODS AND RESULTS: Two spot urine samples (Up/Uc1 and Up/Uc2) were collected on the same day as the collection of a 24-hour urine. A randomly chosen subsample of 50 patients provided a second set of urine samples. The correlation and precision of agreement between the two methods were examined. The predictive intervals were calculated for derived 24-hour proteinuria. The level of agreement was evaluated by the Bland-Altman method and concordance analysis. The limits of agreement were evaluated against the clinical limits of agreement. A cost-benefit analysis (CBA) was performed to obtain the optimum operating points on receiver operating characteristic (ROC) curves for the best decision threshold. Correlations of r = 0.97 and 0.99 were observed between Up/Uc1, Up/Uc2 and 24-hour proteinuria, respectively. The 95% predictive intervals were wide. A high concordance correlation coefficient was obtained. The most of the differences between the two methods fell within the clinical limits of agreement. The Up/Uc1 of 0.26 and 3.20 represent the best thresholds to detect normal and nephrotic proteinuria, respectively. CONCLUSIONS: Despite wide confidence intervals, a good correlation and precision of agreement were demonstrated between the two methods across the whole range of proteinuria, regardless of the level of renal function. The difference between the two methods was less than the biological variability in the protein excretion and its measurement, enabling the methods to be used interchangeably. The optimum thresholds for abnormal and nephrotic range proteinuria were obtained.

Adult↗
PubMed2001

Acute renal failure in a patient with paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder characterized by low-grade, chronic hemolytic anemia accompanied by either thrombocytopenia or leucopenia. Kidney involvement is usually benign and secondary to chronic tubular deposition of hemosiderin. Acute renal failure may occur in association with a hemolytic crisis. We report the case of a 70-year-old Caucasian woman with PNH who developed reversible acute renal failure requiring hemodialysis following a gastointestinal illness. Renal biopsy demonstrated acute tubular necrosis with considerable hemosiderin deposition, but no evidence of vascular thrombosis.

Acute Kidney Injury↗
PubMed1999

Linkage of a gene causing familial focal segmental glomerulosclerosis to chromosome 11 and further evidence of genetic heterogeneity.

Focal segmental glomerulosclerosis (FSGS) is a pathological entity characterized by proteinuria, nephrotic syndrome, and the progressive loss of renal function. It is a common cause of end-stage renal disease (ESRD). Recently, familial forms of FSGS have been identified. Two families with autosomal dominant FSGS were evaluated for linkage using 351 genomic microsatellite markers. Linkage, multipoint analysis, and tests for heterogeneity were performed on the subsequent results. In addition, three small families were used for haplotype analysis. Evidence for linkage was found on chromosome 11q21-q22 for the largest family, with a maximum lod score of 9.89. The gene is currently localized to an 18-cM area between flanking markers D11S2002 and D11S1986. The disease in a second family was not linked to this locus or to a previously described locus on chromosome 19q13. There were no shared haplotypes among affected individuals in the three smaller families. Our findings demonstrate that genetic heterogeneity is prevalent in FSGS in that at least three genes cause the FSGS phenotype. Identification of the genes that cause familial FSGS will provide valuable insights into the molecular basis and pathophysiology of FSGS.

Adolescent↗
PubMed1999

Predicting renal survival in primary focal glomerulosclerosis from the time of presentation.

UNLABELLED: Predicting renal survival in primary focal glomerulosclerosis from the time of presentation. BACKGROUND: To predict the risk of developing chronic renal failure in patients with primary focal glomerulosclerosis (FGS) using predictors available at the time of presentation, a retrospective analysis was performed on 111 patients who were diagnosed at Christchurch Hospital from 1965 to 1998. METHODS: The predictors of outcome included age, gender, systolic and diastolic blood pressure, serum albumin, plasma creatinine, presence of hematuria, and amount of proteinuria (all at the time of presentation). An injury score (combination of percentage of sclerosed glomeruli and proportion of tubulointerstitial fibrosis) was derived from a review of the initial kidney biopsy. Log-logistic accelerated failure time parametric models were used. RESULTS: The median renal survival was 16.4 years (Kaplan-Meier estimate). The best single variable model was that using the proportion of tubulointerstitial fibrosis (global chi-square 55.99, P < 0.0001). However, inclusion of plasma creatinine significantly improved the fit of the model (global chi-square 65.04, P < 0.0001). This joint model was superior to the single-variable model. Both of the models were validated using jackknifing. CONCLUSION: For a patient with primary FGS, these models can be used to predict the risk of developing chronic renal failure at any time and the median renal survival, given the proportion of tubulointerstitial fibrosis and plasma creatinine at the time of presentation.

Adolescent↗
PubMed1999

Clinical and genetic heterogeneity in familial focal segmental glomerulosclerosis. International Collaborative Group for the Study of Familial Focal Segmental Glomerulosclerosis.

BACKGROUND: Familial forms of focal segmental glomerulosclerosis (FFSGS) that exhibit autosomal dominant or recessive patterns of inheritance have been described. The genetic basis of these hereditary forms of FSGS is unknown. One recent study of a kindred from Oklahoma with an autosomal dominant form of FSGS linked this disease to a region of chromosome 19q. In addition, polymorphisms in a gene in this region on chromosome 19q13 have been linked to congenital nephrotic syndrome of the Finnish type. We have ascertained and characterized a large family with autosomal dominant FFSGS (Duke 6530). METHODS: Families were compared for clinical and genetic heterogeneity. To test for linkage of our family to this portion of chromosome 19, genomic DNA was isolated from 102 family members, and polymerase chain reaction was performed using eight microsatellite markers that spanned the area of interest on chromosome 19. Data were evaluated using two-point linkage analysis, multipoint analysis, and an admixture test. RESULTS: Linkage was excluded at a distance of +/- 5 to 10 CM for all markers tested with two-point log10 of the odds of linkage (LOD) scores and from an approximate 60 CM interval in this area of chromosome 19q via multipoint analysis. CONCLUSIONS: FSGS has been called the "final common pathway" of glomerular injury, as it is a frequent pathological manifestation with diverse etiologies. This diversity likely correlates with the genetic heterogeneity that we have established. Thus, our data demonstrate that there are at least two genes responsible for this disease, and there is genetic as well as clinical heterogeneity in autosomal dominant FSGS.

Adolescent↗
PubMed1999

Ambulatory blood pressure monitoring in patients receiving long, slow home haemodialysis.

BACKGROUND: Good blood pressure (BP) control has been reported previously in haemodialysis (HD) patients receiving 8-h dialysis sessions. Home HD allows patients to dialyze for long periods, but there are few data on the BP control achieved by these patients. We studied BP control, using ambulatory blood pressure monitoring (ABPM), in our home-HD patients who were receiving long-hours dialysis. METHODS: Twenty-four patients aged 52.7+/-11 years underwent ABPM. They had been on home HD for 52.9+/-39 months and dialysed for 7.2+/-1.1 h thrice weekly. Two patients were taking antihypertensive drugs. Historical data on BP and weight gains were obtained from the patients' own records. Left ventricular (LV) mass was assessed by echocardiography and total body water (TBW) by bioelectrical impedance. RESULTS: The mean 24-h BP was 129+/-17 mmHg (systolic) and 83+/-14 mmHg (diastolic). The daytime BP was 131+/-17 mmHg (systolic) and 84+/-14 mmHg (diastolic), while the night-time BP was 126+/-22 mmHg (systolic) and 81+/-17 mmHg (diastolic). Six patients (25%) had a normal circadian BP rhythm, but the rest showed a subnormal fall or an increase in BP at night. Mean 24-h BP did not correlate significantly with time on dialysis, dialysis session length, Kt/V, haemoglobin, interdialytic weight gain, or TBW. Twenty-one patients (87%) had LV hypertrophy and 16 of these had diastolic dysfunction. LV mass index was inversely correlated with nocturnal BP fall (r=-0.54, P=0.03). Non-dippers had been treated longer than dippers (29 vs 59.2 months, P=0.03) but they were similar in respect to age, dialysis session length or Hb concentration. CONCLUSIONS: Long, slow haemodialysis at home provides satisfactory daytime BP control in the majority of patients without the need for antihypertensive drugs but abnormal circadian BP rhythm and LV hypertrophy remain common.

Adult↗
PubMed1999

Renal sarcoidosis in Christchurch, New Zealand 1970-1998.

AIM: To identify patients presenting to a nephrologist in whom a diagnosis of sarcoidosis could be made, to assess the relevant causes of renal involvement and to review treatment and long-term follow-up of this group. METHOD: A retrospective review of the computer database PROTON for patients given the diagnosis of sarcoidosis, followed by a case note review of identified patients with respect to the mode of presentation, clinical and laboratory features, treatment and subsequent follow-up. RESULTS: Nineteen patients (15 males) were identified, mean age 45 years, all were Caucasian, and follow-up was four months to 26 years (mean 9.3 years). Most common mode of presentation was acute renal failure (11) during spring/summer (14). Evidence for systemic disease was present in all patients. Mean plasma creatinine on presentation was 0.52 mmol/L and calcium 3.01 mmol/L. Hypercalcaemia was present in 60%. Kidney biopsy was performed in seven patients with the predominant findings of tubular atrophy and interstitial fibrosis; significant granulomata were present in only two. Treatment in all patients was with corticosteroids with good result. Mean long term plasma creatinine was 0.17 mmol/L at 9.3 years. Steroid withdrawal was attempted in all patients, successful in five, with the mean time to relapse of five months in the remaining 14. Mean steroid dose in this group was 7.6 mg on long term follow-up. CONCLUSIONS: Sarcoidosis causes renal dysfunction mainly through altered calcium metabolism. Treatment with corticosteroids is successful in improving renal function, but relapse is common on steroid withdrawal and prolonged treatment is necessary for disease control.

Adult↗
PubMed1999

Hyponatremic-hypertensive syndrome with renal ischemia: an underrecognized disorder.

Renal artery stenosis or occlusion causing the hyponatremic-hypertensive syndrome has been rarely reported. Our impression, however, was that the disorder is not uncommon. Case records from patients in one city (population 350 000) presenting between 1980 and 1997 with hypertension, hyponatremia, and evidence of renal ischemia were scrutinized. Thirty-two patients fulfilling inclusion criteria were identified. Admission supine arterial pressures were high (mean 228/124 mm Hg), but there was a vigorous fall in pressure on standing (26/12.7 mm Hg recorded in 27 patients). Mean plasma concentrations of sodium (129.7 mmol/L) and potassium (2.7 mmol/L) were low, and 24-hour urine protein excretion was elevated in 19 of 26 patients. Twenty-two of the 32 patients were female, the majority were asthenic, and all but 5 were smokers. Symptoms precipitating hospitalization were headache, clouding of consciousness, confusion, weakness, weight loss, thirst, and polyuria. Plasma renin levels, measured in 20 patients, were elevated in most cases and correlated inversely (r=-0.63, P<0.01) with the plasma sodium concentration. The hyponatremic-hypertensive syndrome in patients with renal ischemia is not rare: Rather, it is underreported. It tends to affect elderly asthenic women who smoke heavily. Stimulation of renin release from the ischemic kidney is probably central to the pathophysiology. The syndrome deserves better recognition to ensure appropriate investigations and management.

Adult↗
PubMed1998

Intravenous drug use and glomerular deposition of lipid-like material.

UNLABELLED: We present a series of 5 intravenous drug users (4 male, age range 24-47 years) with glomerular deposition of a lipid-like material. Three patients presented with the nephrotic syndrome, 1 with acute renal failure and 1 with hypertension and an active urinary sediment. All were continuing to use opiates intravenously (mixed with lemon juice or acetic anhydride and sodium bicarbonate). INVESTIGATIONS: plasma creatinine 0.10-0.30 mmol/l, urinary protein excretion 1.0-6.75 g/24 h, hepatitis C antibody positive (4), all seronegative for hepatitis B and HIV. Renal biopsy showed large vacuolated areas consistent with heavy deposition of lipid-like material in all glomerular cells and infiltrating macrophages. Two showed ATN and another FGS. We suggest that these changes are due to the pattern of illicit drug availability and preparation peculiar to these users.

Acute Kidney Injury↗
PubMed1998

Clinical audit of the use of renal biopsy in the management of isolated microscopic hematuria.

Whether renal biopsies are indicated for the investigation of microscopic hematuria is a subject of debate. In this retrospective study we evaluated our use of renal biopsy in patients who presented between 1985 and 1995 with microscopic hematuria but without proteinuria, hypertension or renal insufficiency. Of 111 patients, 75 had a renal biopsy. Histological diagnoses included thin membrane nephropathy (TMN) (36%), IgA nephropathy (IgAN) (23%), non-IgA mesangioproliferative glomerulonephritis (MPGN) (9%), mild glomerular abnormalities (11%), focal global glomerulosclerosis (FGS) (4%) and normal (17%). After 85 patients had been followed for a mean of 43 months there were no deaths, 3 patients had proteinuria (IgAN 2, no biopsy 1), 1 had proteinuria and renal insufficiency (immune negative MPGN) and 11 were hypertensive (TMN 3, IgAN 2, normal 2, FGS 1, no biopsy 3). Hematuria resolved in 23 patients. Only 11 patients were still attending the nephrology clinic and 27% of the patients who were advised to continue annual follow-up with family doctors had not done so. In summary, the information obtained from renal biopsy rarely altered clinical management. Hypertension developed in 13% of the patients followed but it was not predicted by the biopsy result. Although a renal biopsy will usually be diagnostic it is difficult to justify in patients who have isolated microscopic hematuria.

Adult↗