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Biomedical subjects

P Altmann

Publications and source records attributed to P Altmann.

At least 19 recordsLinked to original sources
PubMed2006

Cognitive function in Stage 5 chronic kidney disease patients on hemodialysis: no adverse effects of lanthanum carbonate compared with standard phosphate-binder therapy.

Patients with Stage 5 chronic kidney disease who have hyperphosphatemia require treatment with phosphate binders to lower serum phosphorus levels. Existing binders are effective but may be associated with important safety disadvantages. Lanthanum carbonate is a phosphate binder with demonstrated efficacy, safety, and tolerability in clinical trials. Changes in cognitive function were evaluated over time using the Cognitive Drug Research computerized cognitive assessment system (Simple Reaction Time, Digit Vigilance Task, Choice Reaction Time, Numeric Working Memory, and Delayed Picture Recognition) in 360 hemodialysis patients who were enrolled in a 2-year, multicenter, comparative study of lanthanum carbonate versus standard therapy. A decline in cognitive function from baseline was observed in both groups. The deterioration in cognitive function was similar in both the lanthanum carbonate and standard therapy groups. One parameter - Numeric Working Memory - showed a statistically significant between-group difference in favor of lanthanum carbonate (P=0.02). Given the magnitude of the changes, however, and the differences that were observed at baseline between treatment groups, the clinical significance of this difference is doubtful. This study demonstrates that cognitive function deteriorates in hemodialysis patients over a 2-year time period. Use of lanthanum carbonate as a phosphate binder does not adversely affect cognitive function compared with standard therapy.

Adult↗
PubMed2004

Effects of carnitine supplementation on muscle metabolism by the use of magnetic resonance spectroscopy and near-infrared spectroscopy in end-stage renal disease.

BACKGROUND/AIM: A defect in skeletal muscle mitochondrial metabolism develops in patients with chronic renal failure on haemodialysis. Treatment with carnitine, a compound essential for normal mitochondrial function, has been suggested to have significant benefits in such patients, so we carried out a study to see if carnitine acts by improving muscle bioenergetics and function. METHODS: In a phase II randomised double-blind trial, patients with end-stage renal disease received placebo or intravenous L-carnitine (20 mg/kg dry body weight three times weekly after haemodialysis) for 16 weeks (n = 13 in each group). 31P magnetic resonance spectroscopy, 1H magnetic resonance imaging and near-infrared spectroscopy were used to measure muscle bioenergetics and function at baseline and at 16 weeks. RESULTS: There were no significant differences between groups at baseline. Mean plasma carnitine rose 10-fold in the carnitine group but was unchanged in the placebo group. L-carnitine had no statistically significant effect on any of the parameters measured. The rate of proton efflux from muscle, as a measure of tissue perfusion, was low in both groups and was not affected by treatment. CONCLUSIONS: The study failed to show any significant effect of 16 weeks' L-carnitine supplementation on these objective measures of muscle metabolism and function. Slow proton efflux from muscle provides evidence supporting low blood flow and, therefore, decreased oxygen availability, as an underlying mechanism for muscle mitochondrial dysfunction in this disorder.

Blood Chemical Analysis↗
PubMed2003

Giant lichenification of the scalp.

Lichenification is characterized clinically by thickening of areas of skin as a result of the itch-scratch cycle and therefore is seen in conditions associated with chronic pruritus. The characteristic feature of giant lichenification is the occurrence of tumour-like growths with a warty cribriform surface. We describe a renal transplant patient presenting with giant lichenification of the scalp following an attack of herpes zoster at the same site. Chronic pruritus following scalp dysaethesia secondary to herpes zoster was considered the most likely explanation for the occurrence of these lesions.

Adult↗
PubMed2002

Clinical usefulness of cystatin C for the estimation of glomerular filtration rate in type 1 diabetes: reproducibility and accuracy compared with standard measures and iohexol clearance.

OBJECTIVE-Assessment and follow-up of early renal dysfunction is important in diabetic nephropathy. Plasma creatinine is insensitive for a glomerular filtration rate (GFR) >50 ml/min and creatinine clearance is unwieldy and subject to collection inaccuracies. We aimed to assess the reproducibility, reliability, and accuracy of plasma cystatin C as a measure of GFR ranging from normal to moderate impairment due to type 1 diabetes in the presence of a normal plasma creatinine concentration. RESEARCH DESIGN AND METHODS-A sensitive immunoturbidimetric cystatin C assay was examined in 29 subjects with type 1 diabetes and 11 nondiabetic subjects. Duplicate measurements of the following were collected from each subject, 2 weeks apart: cystatin C, enzymatic plasma creatinine, 24-h creatinine clearance, GFR estimated from plasma creatinine by the Cockcroft-Gault equation, and iohexol clearance as a gold standard. RESULTS-Iohexol clearance ranged from 35 to 132 ml. min(-1). 1.73 m(-2). Plasma cystatin C compared well with the other clinically used tests. The reliability of cystatin C, as assessed by the discriminant ratio, was superior to creatinine clearance (3.4 vs. 1.5, P < 0.001) and the correlation of cystatin C with iohexol clearance (Rs -0.80) was similar to that of creatinine clearance (Rs -0.74) and superior to that of plasma creatinine and the Cockcroft-Gault estimate (Rs -0.54 and 0.66, respectively). Duplicate estimations were used to provide an unbiased equation to convert plasma cystatin C to GFR. CONCLUSIONS-Based on this study, cystatin C is a more reliable measure of GFR than creatinine clearance, is more highly correlated with iohexol clearance than plasma creatinine, and is worthy of further investigation as a clinical measure of GFR in type 1 diabetes.

Adult↗
PubMed2000

[Microsurgical vasovasostomy in the age of modern reproduction medicine. A cost-benefit analysis].

WS represents the standard procedure of choice for the treatment of obstructive azoospermia following vasectomy. However, recently, ICSI has been suggested by some to represent the solution for all cases of male factor infertility regardless of its etiology based on its success rates. Therefore, we compared VVS to MESA/TESE and ICSI in terms of pregnancy, complications, and costs. Between 1/93 and 6/98 157 VVS was performed microsurgically using the 2-layer technique in 157 patients following prior vasectomy. Between 9/94 and 9/97 69 couples underwent MESA/ICSI for epididymal obstruction not amenable to micro-surgical reconstruction such as post-inflammatory obstruction and congenital absence of the vas deferens; in the same time period 42 couples underwent TESE/ICSI for azoospermia of testicular origin due to cryptorchidism, testicular atrophy, obstruction of the rete testis. In most cases MESA or TESE and ICSI were performed metachronously. Mean intervall of vasal obstruction was 7.6 (0.5-18) years; patency after VVS was 77%, pregnancy rate was 52%. Local complication rate was 4.7%, no major complications were observed. Costs per life birth after VVS were as high as 5,447,-DM or 2,800 Euro. Pregnancy rates after MESA/TESE and ICSI were 22.5% and 19.5%, respectively with 16 singletons, 3 twins and 3 abortions; local complications occurred in 3.9% of the men. Multiple birth were noticed in 15.8% following ICSI, but only in 0.7% following VVS. 5.7% and 1.4% of the female partners experienced serious complications as a mild or severe ovarian hyperstimulation-syndrome, respectively. Costs per life birth after MESA/TESE cycle were as high as 28,804,-DM or 14,100 Euro. Even in the era of ICSI microsurgical vasovasostomy represents the standard approach for obstructive azoospermia following vasectomy. Based on a cost-benefit analysis VVS is more successful in terms of pregnancy rates (52% vs. 22.5%). We conclude that MESA/ICSI should be reserved for patients not amenable for microsurgical reconstruction.

Adult↗
PubMed2000

Microsurgical vasovasostomy versus microsurgical epididymal sperm aspiration/testicular extraction of sperm combined with intracytoplasmic sperm injection. A cost-benefit analysis.

PURPOSE: Vasovasostomy (VVS) represents the standard therapy of choice for the treatment of obstructive azoospermia following vasectomy. However, recently, intracytoplasmic sperm injection (ICSI) has been suggested by some to represent the solution for all cases of malefactor infertility regardless of its etiology based on its success rates. Therefore, we compared VVS to microsurgical epididymal sperm aspiration (MESA)/testicular extraction of sperm (TESE) and ICSI in terms of pregnancy, complications, and costs. PATIENTS AND METHODS: Between 1/93 and 6/98, 157 VVS were performed microsurgically using the double-layer technique. Between 9/94 and 9/97, 69 and 42 couples underwent MESA/ICSI and TESE/ICSI, respectively, for epididymal obstruction and azoospermia of testicular origin. RESULTS: The mean interval of vasal obstruction was 7.6 (0.5-18) years; patency after VVS was 77%, pregnancy rate was 52%. Local complication rate was 4.7%, no major complications were observed. Costs per life birth after VVS were 5,447 DM or 2,793 Euro. Pregnancy rates after MESA/TESE and ICSI were 22.5 and 19.5%, respectively, with 16 singletons, 3 twins and 3 abortions; local complications occurred in 3.9% of the men. Multiple births were noticed in 15.8% following ICSI, but in only 0.7% following VVS. 5.7 and 1.4% of the female partners experienced serious complications (mild or severe ovarian hyperstimulation syndrome, respectively). Costs per life birth after a MESA/TESE cycle amounted to 28,804 DM or 14,547 Euro. CONCLUSIONS: Even in the era of ICSI, microsurgical VVS represents the standard approach for obstructive azoospermia following vasectomy. Based on a cost-benefit analysis, VVS is more successful in terms of pregnancy rates (52 vs. 22.5%). VVS does not expose the female partners to complications following treatment of male infertility. In contrast to ICSI, multiple birth rates do not increase after VVS. We conclude that MESA/ICSI should be reversed for patients who are not amenable for microsurgical reconstruction.

Adult↗
PubMed1999

Disturbance of cerebral function in people exposed to drinking water contaminated with aluminium sulphate: retrospective study of the Camelford water incident.

OBJECTIVE: To establish whether people exposed to drinking water contaminated with 20 tonnes of aluminium sulphate in the Camelford area of Cornwall in the south west of England in July 1988 had suffered organic brain damage as opposed to psychological trauma only. DESIGN: Retrospective study of affected people. PARTICIPANTS: 55 affected people and 15 siblings nearest in age to one of the group but who had not been exposed to the contaminated water were studied. MAIN OUTCOME MEASURES: Various clinical and psychological tests to determine medical condition and anxiety levels in affected people. Assessment of premorbid IQ (pFSIQ) with the national adult reading test, a computerised battery of psychomotor testing, and measurement of the difference in latencies between the flash and pattern visual evoked potentials in all participants. RESULTS: The mean (SE) pFSIQ was above average at 114.4 (1.1). The most sensitive of the psychomotor tests for organic brain disease was the symbol digit coding (SDC) test (normal score 100, abnormal <85). PARTICIPANTS performed less well on this test (54.5 (6.0)) than expected from their pFSIQ (P<0.0001) and a little less poorly on the averaged less discriminating tests within the battery (86.1 (2.5), P<0.0001). In a comparison with the 15 sibling pairs (affected people's age 41.0 (3.3) years v sibling age of 42.7 (3.1) years (P=0.36) the exposed people had similar pFSIQ (114.7 (2.1)) to their siblings (116.3 (2.1), (P=0.59) but performed badly on the symbol digit coding test (51.8 (16.6)) v (87.5 (4.9) for siblings, P=0.03). The flash-pattern differences in exposed people were greater than in 42 unrelated control subjects of similar age (27.33 (1.64) ms v 18. 57 (1.47) ms, P=0.0002). The 15 unexposed siblings had significantly better flash-pattern differences than their affected siblings (13.4 (2.4) ms v 29.6 (2.9) ms, P=0.0002). No effect of anxiety could be shown on these measurements from the analysis of the anxiety scores of exposed people. CONCLUSION: People who were exposed to the contaminated water at Camelford suffered considerable damage to cerebral function, which was not related to anxiety. Follow up studies would be required to determine the longer term prognosis for affected individuals.

Adolescent↗
PubMed1998

Silicon and aluminium interactions in haemodialysis patients.

BACKGROUND: Aluminium toxicity in dialysis patients is well described. Aluminium has a close chemical affinity with silicon. Silicon may have a role in protection against aluminium toxicity. METHODS: We measured serum aluminium and silicon levels from haemodialysis patients from four different centres. RESULTS: Though no relationship was seen across all centres combined, in one centre there was a reciprocal relationship in patients on home haemodialysis (who did not require reverse osmosis). Median (range) aluminium levels were higher, 2.2 (0.4-9.6) micromol/l when serum silicon was less than 150 micromol/l, and lower, 1.1 (0.2-2.8) micromol/l when serum silicon levels were greater than 150 micromol/l (P = 0.03). CONCLUSIONS: In patients treated by haemodialysis without reverse osmosis high serum silicon concentrations were associated with lower serum aluminium concentrations than those with low serum silicon. Further work needs to confirm a preventative role for silicon in the accumulation and subsequent toxicity of aluminium in dialysis patients.

Aluminum↗
PubMed1997

High serum D-lactate in patients on continuous ambulatory peritoneal dialysis.

BACKGROUND: As abnormally high serum D-lactate levels may cause neurological impairment, we determined whether patients undergoing continuous ambulatory peritoneal dialysis (CAPD) with lactate-containing fluids have increased serum D-lactate concentrations. METHODS: D- and L-lactate concentrations were determined in peritoneal dialysis fluids and in serum from control subjects (n = 10), haemodialysis patients (n = 10), and CAPD patients (n = 30) before and after 1 h of dialysis. RESULTS: We found the median D-lactate concentration in Dianeal CAPD fluid to be 26 mM (range 19-27), whereas it was less than 0.5 mM in DPCA2 fluid. Control, haemodialysis, and CAPD (DPCA2) patient median serum D-lactate concentrations were below 0.07 mM. However, CAPD (Dianeal) patient serum D-lactate concentrations were 4-fold higher than controls (P < 0.0001), at 0.28 mM, an hour after instillation of D-lactate-containing fluid. Three patients, whose serum D-lactate averaged 0.59 mM, were found to have D-lactate concentrations at 0.22 mM after overnight cessation of dialysis. CONCLUSION: We conclude that CAPD with D-lactate-containing fluids raises serum D-lactate to abnormal levels.

Adult↗
PubMed1990

Defective gallium-transferrin binding in Alzheimer disease and Down syndrome: possible mechanism for accumulation of aluminium in brain.

The plasma distribution of gallium (as an analogue of aluminium) was investigated in patients with Alzheimer disease, Down syndrome, or stroke dementia, in subjects on haemodialysis for chronic renal failure, and in healthy controls. Gallium-transferrin binding was significantly lower in the Alzheimer (mean [SEM] 7.9 [1.1]%) and Down syndrome groups (6.9 [0.7]%) than in the controls (17.1 [1.6]%), whereas stroke dementia and haemodialysis patients had normal binding. There were no differences among the groups in plasma citrate concentration. The plasma transferrin concentration was slightly lower in the Alzheimer and Down syndrome groups than in the controls, but even lower in stroke dementia patients (1.74 [0.14] g/l vs 2.98 [0.18] g/l in controls). Transferrin iron saturation was higher in the Alzheimer (58.9%) and Down syndrome groups (81.6%) than in the controls (39.0%) or stroke dementia patients (33.4%). This deficiency of gallium/aluminium binding would leave more unbound aluminium which could move readily into the brain, where it has neurotoxic effects.

Adult↗
PubMed1990

Pharmacokinetics of once daily intra-peritoneal aztreonam and vancomycin in the treatment of CAPD peritonitis.

The pharmacokinetics of aztreonam and vancomycin were studied in six adult patients who developed peritonitis during Continuous Ambulatory Peritoneal Dialysis. Aztreonam 3 g was added to the first exchange in each 24 h period with vancomycin 500 mg on the first day and 250 mg on each subsequent day (provided the pre-dose serum vancomycin concentration was less than 10 mg/l) for a total of ten days. Aztreonam and vancomycin concentrations were measured in the serum and dialysate at 1, 2, 6, 12, 18 and 24 h after the initial dose and pre-dose on days 5 and 10. By the end of the ten day study all patients had recovered clinically and had a normal dialysate. For aztreonam, the mean peak serum concentration was 84.3 mg/l (range 59.6-102.8), the mean 24 h pre-dose serum concentration was 23.0 mg/l (range 8.6-39.2) and the mean 24 h pre-dose dialysate concentration was 15.5 mg/l (range 5.0-32.0). For vancomycin, the mean peak serum concentration was 10.2 mg/l (range 8.1-12.6), the mean 24 h pre-dose concentration was 5.5 mg/l (range 3.6-6.4), and the mean 24 h pre-dose dialysate concentration was 3.4 mg/l (range 2.4-4.6). In the treatment of CAPD peritonitis, once daily intra-peritoneal administration of aztreonam 3 g with vancomycin 500 mg initially and 250 mg on subsequent days (serum concentrations permitting) provides concentrations of antibiotic in both the serum and dialysate throughout the 24 h period in excess of the inhibitory concentrations of those organisms most frequently encountered in this condition.

Aztreonam↗