PubMed Health⌕ Search

Biomedical subjects

S Waldek

Publications and source records attributed to S Waldek.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of hypogonadism in male patients with renal failure.

BACKGROUND: Hypogonadism in men may be secondary to renal failure and is well recognised in patients with end-stage renal disease. It is thought to contribute to the sexual dysfunction and osteoporosis experienced by these patients. However, the association between hypogonadism and lesser degrees of renal dysfunction is not well characterised. METHODS: The gonadal status of 214 male patients (mean age 56 (SD 18) years) attending a renal centre was studied; 62 of them were receiving haemodialysis and 22 continuous ambulatory peritoneal dialysis for end-stage renal disease, whereas 34 patients had functioning renal transplants and 96 patients were in the low-clearance phase. Non-fasting plasma was analysed for testosterone, follicle-stimulating hormone, luteinising hormone, sex hormone-binding globulin, parathyroid hormone and haemoglobin. Creatinine clearance was estimated in patients not on dialysis, and Kt/V and urea reduction ratio were assessed in patients on dialysis. Testosterone concentrations were classified as normal (>14 nmol/l), low-normal (10-14 nmol/l) or low (<10 nmol/l). RESULTS: 56 (26.2%) patients had significantly low testosterone levels and another 65 (30.3%) had low-normal levels. No significant changes were seen in sex hormone-binding globulin or gonadotrophin levels. Gonadal status was not correlated with haemoglobin level, parathyroid hormone level, creatinine clearance, or dialysis duration or adequacy. CONCLUSION: Over half of patients with renal failure, even in the pre-dialysis phase, have low or low-normal levels of testosterone, which may be a potentially reversible risk factor for osteoporosis and sexual dysfunction. These patients may be candidates for testosterone-replacement therapy, which has been shown to improve bone mineral-density and libido in men with low and low-normal testosterone levels.

Adolescent↗
PubMed2005

Measurement of urinary CDH and CTH by tandem mass spectrometry in patients hemizygous and heterozygous for Fabry disease.

Fabry disease is an X-linked disorder of glycosphingolipid metabolism resulting from a deficiency of the lysosomal enzyme alpha-galactosidase A. This deficiency leads to the progressive accumulation, in lysosomes of visceral tissues and in body fluids of hemizygotes, of the glycosphingolipids globotriaosylceramide (CTH, Gb(3) or GL-3) and galabiosylceramide (CDH) and to a lesser extent the blood group AB and B related glycolipids. Elevated levels of the glycosphingolipids are found in the urine of hemizygous males with the classic phenotype, but it is not known whether all symptomatic or asymptomatic heterozygotes have elevated levels. We have therefore measured CTH and CDH quantitatively in a multiplex assay using tandem mass spectrometry in urine from a large cohort (44) of genetically proven or obligate heterozygotes including four with the N215S mutation, from classic hemizygotes (28), from cardiac variant hemizygotes with the N215S mutation (6) and from normal controls. The levels of CTH and CDH were related to both creatinine and sphingomyelin. Urinary CTH was elevated in all 28 classic hemizygotes but only in 4/6 of the cardiac variants. The level was within or just above the normal reference range in the four individuals heterozygous for the N215S mutation but was elevated in 38/40 of the other heterozygotes. Similar results were obtained for CDH, except that only 34/40 heterozygotes had an elevated level. The level of CDH was not elevated in the four heterozygotes and 4/6 of the hemizygotes for the N215S mutation. Combining the levels of CTH and CDH did not improve the discrimination of heterozygotes from controls. The ratio of CDH to CTH was higher in heterozygotes than in hemizygotes. Measurement of urinary CTH gave the best discrimination of heterozygotes from controls.

Chromatography, Liquid↗
PubMed2005

Is globotriaosylceramide a useful biomarker in Fabry disease?

AIM: The aim of this study was to determine whether globotriaosylceramide (Gb3) is a useful biomarker in Fabry disease. METHODS: The levels of Gb3 were measured in plasma and urine by tandem mass spectrometry in untreated hemizygotes and heterozygotes with Fabry disease and in healthy controls, and the levels were monitored in patients on treatment with enzyme replacement therapy (ERT). RESULTS: Hemizygotes with classic Fabry disease showed elevated levels of Gb3 in both plasma and urine and could readily be distinguished from normal controls. Male patients with the N215S mutation had normal levels in their plasma but 50% had marginally elevated levels in their urine. Thirty-three percent of proven heterozygotes had elevated Gb3 concentrations in plasma but 97% of those without the N215S mutation (36/37) had an elevated level in urine. The four heterozygotes with the N215S mutation had normal Gb3 levels in urine. The level of Gb3 in plasma initially fell following the start of ERT in all patients who had an elevated level before treatment. However, in a few patients the level subsequently rose. Similar results were found for the levels of Gb3 in urine. CONCLUSION: Gb3 is not an ideal marker of Fabry disease or the response to treatment in all patients. Plasma and urine levels of Gb3 cannot be used as a marker of Fabry disease in patients with the N215S mutation and many heterozygotes do not have elevated Gb3 levels in plasma. The urine concentration is more informative in heterozygotes and can be used as a measure of the response to therapy. The fall in Gb3 levels in patients receiving ERT was not sustained in some patients, despite a clinical improvement. Additionally, Gb3 cannot be used to monitor the response to treatment in patients who initially have normal plasma and urine concentrations of this glycolipid.

Biomarkers↗
PubMed2001

Safety and efficacy of recombinant human alpha-galactosidase A replacement therapy in Fabry's disease.

BACKGROUND: Fabry's disease, lysosomal alpha-galactosidase A deficiency, results from the progressive accumulation of globotriaosylceramide and related glycosphingolipids. Affected patients have microvascular disease of the kidneys, heart, and brain. METHODS: We evaluated the safety and effectiveness of recombinant alpha-galactosidase A in a multicenter, randomized, placebo-controlled, double-blind study of 58 patients who were treated every 2 weeks for 20 weeks. Thereafter, all patients received recombinant alpha-galactosidase A in an open-label extension study. The primary efficacy end point was the percentage of patients in whom renal microvascular endothelial deposits of globotriaosylceramide were cleared (reduced to normal or near-normal levels). We also evaluated the histologic clearance of microvascular endothelial deposits of globotriaosylceramide in the endomyocardium and skin, as well as changes in the level of pain and the quality of life. RESULTS: In the double-blind study, 20 of the 29 patients in the recombinant alpha-galactosidase A group (69 percent) had no microvascular endothelial deposits of globotriaosylceramide after 20 weeks, as compared with none of the 29 patients in the placebo group (P<0.001). Patients in the recombinant alpha-galactosidase A group also had decreased microvascular endothelial deposits of globotriaosylceramide in the skin (P<0.001) and heart (P<0.001). Plasma levels of globotriaosylceramide were directly correlated with clearance of the microvascular deposits. After six months of open-label therapy, all patients in the former placebo group and 98 percent of patients in the former recombinant alpha-galactosidase A group who had biopsies had clearance of microvascular endothelial deposits of globotriaosylceramide. The incidence of most treatment-related adverse events was similar in the two groups, with the exception of mild-to-moderate infusion reactions (i.e., rigors and fever), which were more common in the recombinant alpha-galactosidase A group. IgG seroconversion occurred in 88 percent of patients who received recombinant alpha-galactosidase A. CONCLUSIONS: Recombinant alpha-galactosidase A replacement therapy cleared microvascular endothelial deposits of globotriaosylceramide from the kidneys, heart, and skin in patients with Fabry's disease, reversing the pathogenesis of the chief clinical manifestations of this disease.

Adolescent↗
PubMed2001

Increasing the diagnostic yield of renal angiography for the diagnosis of atheromatous renovascular disease.

Atheromatous renovascular disease (ARVD) is a common cause of hypertension and chronic renal failure (CRF). In this unit, intravenous digital subtraction angiography (DSA) (or intraarterial DSA if indicated) is used as a screening angiographic study when ARVD is suspected. However, increased use of these investigations has resulted in a longer waiting time for angiography. As the majority of studies are negative for ARVD, clinical features and results of investigations of patients undergoing angiography were reviewed to identify those having the greatest likelihood of ARVD. The clinical notes were reviewed for all 249 patients undergoing angiography over an 18-month period. Primary indications for investigation were: hypertension 71 (28.5%), CRF 156 (62.7%) and CRF with severe hypertension 22 (8.8%). 12 of the CRF patients had end-stage renal failure. 166 (66.7%) patients had no evidence of ARVD, while only 83 (33.3%) patients showed some degree of ARVD, 29 (35%) of which had bilateral renal artery disease. There was no significant difference between the ARVD group and the non-ARVD group for mean age (69.0 years vs 63.3 years), male to female ratio, history of smoking (68.7% vs 55.4%), severe hypertension (10.8% vs 9.0%), hypercholesterolaemia (61.4% vs 47.0%), diabetes mellitus (28.6% vs 25.3%) or angiotensin converting enzyme inhibitor-related renal dysfunction (9.6% vs 6.1%). More patients in the ARVD group were investigated for CRF than in the non-ARVD group, as reflected by the higher serum creatinine level and the lower creatinine clearance in the ARVD group. 55 (33.1%) of the non-ARVD patients had no comorbid vascular disease, vascular bruits or ultrasound discrepancy in the size of the two kidneys, whereas all ARVD patients had at least one of these features (negative predictive value 100%). All three features were present in 19.3% of ARVD patients but in only 3.0% of the non-ARVD patients (positive predictive value 76.2%, specificity 97%). We plan to rationalize the criteria for angiography in the light of these findings, anticipating an increase in the diagnostic yield of renal angiography from its current 33.3% to above 42%.

Adult↗
PubMed2001

Isolated sarcoid granulomatous interstitial nephritis: review of five cases at one center.

AIMS: To identify any clinical or biochemical parameters which determine prognostic outcome in isolated sarcoid granulomatous interstitial nephritis presenting with renal failure. METHODS: A review of five cases of renal failure due to isolated sarcoid granulomatous interstitial nephritis, which presented to Hope Hospital over the 7-year period 1994 to 2000. Follow-up averaged 35 months with a range of 11 to 73 months. RESULTS: Only one patient had an elevated serum ACE at presentation, reflecting the suboptimal sensitivity of this test as a marker in sarcoidosis and the limited extent of disease in these patients. Four of the five cases had a marked improvement in creatinine clearance within 10 days of starting oral prednisolone. Two patients required acute hemodialysis on presentation. Their renal failure responded to treatment with steroids, enabling withdrawal of dialysis within 10 days. All patients remained dialysis-independent although serum creatinine levels rose during follow-up. One patient experienced a relapse that responded to an increased dose of steroid. CONCLUSIONS: Serum ACE is not reliable in the diagnosis of renal failure due to sarcoid interstitial nephritis and the diagnosis can only be made on renal biopsy. First-line treatment with oral prednisolone results in a rapid improvement in creatinine clearance although prolonged treatment may be needed to prevent a relapse.

Aged↗
PubMed2000

Changes in lipid profiles in non diabetic, non nephrotic patients commencing continuous ambulatory peritoneal dialysis.

This study examined the effect on patient lipid profile of commencing continuous ambulatory peritoneal dialysis (CAPD). We followed eighteen non diabetic, non nephrotic patients for 9 months before and after dialysis commencement and compared lipid profiles. Mean cholesterol levels rose from 4.98 mmol/L to 5.42 mmol/L (p < 0.05). This change was chiefly due to a rise in low density lipoprotein (LDL) cholesterol. The LDL cholesterol rose after dialysis commencement and continued to rise up to 9 months later. High-density lipoprotein (HDL) cholesterol remained stable. Serum albumin and body weight fell during follow-up, suggesting that the rise in cholesterol was not a reflection of enhanced nutritional status. This study highlights the pro-atherogenic change in lipids that results from commencing CAPD. This phenomenon is not seen in hemodialysis, and it should be considered when selecting a dialysis modality, given the increased risk of cardiovascular disease in the dialysis population.

Cholesterol↗
PubMed1998

Risk of morbidity from renovascular disease in elderly patients with congestive cardiac failure.

BACKGROUND: Renovasular disease commonly affects elderly people. Elderly patients with heart failure are routinely treated with angiotensin-converting-enzyme (ACE) inhibitors, which may increase risk of renal dysfunction. We investigated the frequency of renovascular disease among elderly people with heart failure. METHODS: From the local population of Salford, UK, we recruited 86 patients with heart failure with a mean age of 77.5 (SD 5.6) years, who were admitted as acute emergencies or who attended general medical clinics. We selected patients by intention to treat with ACE inhibitors. We used captopril renography to screen for renovascular disease. All patients with abnormal renograms underwent magnetic-resonance angiography of the renal arteries as well as 40% of patients with normal renograms as negative controls. FINDINGS: Magnetic-resonance angiography showed severe renovascular disease (>50% renal-artery stenosis or occlusion) in 29 (34%) patients. Captopril renography had an estimated sensitivity of 78.8% (95% CI 72.7-97.8) and specificity of 94.3% (67.6-97.3) for detection of renovascular disease. The estimated positive predictive value of captopril renography was 89.7% and the negative predictive value was 87.5%. Patients with renovascular disease had worse renal function (mean creatinine 201 [SD 56] vs 136 [40] pmol/L, p<0.001), were older (mean age 80.7 [5.6] vs 76.8 [5.3] years, p<0.01), and were more likely than patients without renovascular disease to have peripheral arterial disease. INTERPRETATION: Some elderly patients with occult renovascular disease on ACE inhibitors will be at risk of developing uraemia. Renal function should be closely monitored to detect any deterioration early.

Aged↗
PubMed1993

Transverse myelitis as the presentation of Jo-1 antibody syndrome (myositis and fibrosing alveolitis) in long-standing ulcerative colitis.

A 32-yr-old woman with long-standing ulcerative colitis developed paraesthesiae, sensory loss and muscle weakness shown by magnetic resonance scan to be due to transverse myelitis in the cervical spinal cord. More than 12 months later, she developed dermatomyositis and fibrosing alveolitis and was found to have the Jo-1 antibody. Her condition worsened despite high dose oral prednisolone but improved following intravenous methylprednisolone, immunosuppressive therapy and plasma exchange. This is the first reported case of a neurological presentation of the Jo-1 antibody syndrome. We speculate that the association with ulcerative colitis may have been causal rather than coincidental and suggest that plasma exchange should be considered together with aggressive immunosuppression in seriously ill patients with this disease.

Adult↗
PubMed1992

Estimation of renal tubular secretion in man, in health and disease, using endogenous N-1-methylnicotinamide.

We have been investigating the possibility of using the renal clearance of endogenous N-1-methylnicotinamide (NMN) as a marker of renal tubular function. Sixty-three subjects (11 healthy volunteers and 52 patients with renal impairment) were used for this study. The subjects were divided into three groups according to their creatinine clearance: group 1, over 80 ml/min; group 2, between 30 and 80 ml/min, and group 3, less than 30 ml/min. The correlation between NMN and creatinine clearance was compared for each group. A good correlation (r = 0.84) was found for groups 1 and 3 (r = 0.76), whereas for group 2, a poor correlation was found (r = 0.43). For subjects with mild renal impairment (group 2), there was clear evidence of glomerulo-tubular imbalance manifest by a larger variability in NMN clearance than creatinine clearance and an essentially non-parallel decline in these two parameters for this group. When all subjects were grouped together, the relationship between the clearance of NMN and of creatinine was best described by a 3-term polynomial equation (r = 0.93). NMN clearance is a potentially useful non-invasive marker of renal tubular function in man and provides additional information to that provided by the measurement of creatinine clearance alone. This substance should be more fully evaluated as a potential diagnostic aid.

Adult↗
PubMed1992

Nephrotic-range proteinuria associated with right atrial myxoma.

A case of right atrial myxoma presenting with right heart failure and proteinuria is described. Proteinuria was variable and this corresponded with the degree of systemic venous congestion. On one occasion the proteinuria was within the nephrotic range. There was no evidence of intrinsic renal pathology. The right heart failure and proteinuria resolved after tumour removal, suggesting that the etiology of urinary protein loss was a reversible increase in glomerular permeability.

Aged↗
PubMed1990

Renovascular disease and renal complications of angiotensin-converting enzyme inhibitor therapy.

Renal complications of angiotensin-converting enzyme (ACE) inhibitor therapy are widely recognized, but few authors have documented the incidence or spectrum of these conditions. In a retrospective study of 530 consecutive patients presenting to our unit as acute uraemic emergencies over a six-year period, 85 (16 per cent) had renovascular disease that was considered to be responsible for their loss of renal function. Twenty-one (4 per cent) patients had uraemia which could be clearly attributable to ACE inhibitor treatment; 18 of these cases were shown to have significant renovascular pathology. Following withdrawal of the ACE inhibitor the renal failure reversed in the majority of patients. We also examined 400 consecutive hypertensive patients referred over a similar period and, although vascular imaging was performed only when it was considered to be clinically indicated, 58 (14.5 per cent) of these patients were shown to have renovascular pathology. A further five patients with stable chronic renal disease were seen to have a deterioration in their glomerular filtration rate coincident with commencement of ACE inhibitor therapy; this reversed when the agents were withdrawn. These observations indicate that significant renovascular disease may be more common than has been hitherto recognized and that injudicious use of ACE inhibitors may result in serious complications. Methods which may minimize such iatrogenic disease are suggested.

Acute Disease↗