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Biomedical subjects

J H Turney

Publications and source records attributed to J H Turney.

At least 19 recordsLinked to original sources
PubMed2000

Effect of peritoneal fluid on whole body and segmental multiple frequency bioelectrical impedance in patients on peritoneal dialysis.

OBJECTIVE: We investigated the ability of whole body and segmental multiple frequency bioelectrical impedance (MFBIA) to detect peritoneal fluid in peritoneal dialysis patients. DESIGN: Prospective study. SETTING: Teaching hospital renal unit. SUBJECTS: Patients on regular peritoneal dialysis. INTERVENTIONS: Whole body and segmental MFBIA measurements before and after drainage of peritoneal fluid. RESULTS: Changes estimated by MFBIA in total body water (-0.4 (0.8) litres) and extracellular water (-0.3 (0.3) litres) were much lower than the actual changes (2.0 (0.4) litres), P<0.0001. Derived resistances Recf and Ricf increased significantly for the trunk but not for total body measurements and changes did not correlate with volumes of fluid drained. CONCLUSIONS: MFBIA is limited in its ability to detect intraperitoneal fluid, using both whole body and segmental techniques.

Adult↗
PubMed2000

Effects of icodextrin in automated peritoneal dialysis on blood pressure and bioelectrical impedance analysis.

BACKGROUND: Glucose absorption from glucose-based dialysis fluids limits ultrafiltration from the daytime dwell in automated peritoneal dialysis (APD). Icodextrin may allow greater ultrafiltration during the daytime period in APD, enhancing fluid control. METHODS: A 7.5% icodextrin dialysate was compared with a 2. 27% glucose dialysate for the daytime dwell in 14 subjects on APD. Blood pressure, weight and body water compartments estimated by multifrequency bioelectrical impedance (MFBIA) were determined in subjects using 2.27% glucose as the daytime dwell and then repeated 1 month after switching to icodextrin. RESULTS: Icodextrin resulted in symptomatic hypotension requiring reduction of antihypertensive medication in six of the 14 patients. Despite this reduction in treatment, systolic blood pressure fell from 142.4 (23.9) mmHg to 122.9 (17.7) mmHg, P<0.005, and diastolic blood pressure tended to fall from 82.8 (9.8) mmHg to 76.8 (10.1) mmHg, P=0.075. Change in systolic blood pressure significantly correlated with changes in weight (r=0.62, P<0.05) and MFBIA estimates of total body water (TBW) (r=0.56, P<0.05), extracellular water (ECW) (r=0.79, P<0.002), extra/intracellular water ratio (ECW/ICW) (r=0.72, P<0.01) and derived resistances R(ecf) of ECW (r=-0.69, P<0.01) and R(inf) of TBW (r=-0.66, P<0.02). Changes in diastolic blood pressure significantly correlated with changes in ECW (r=0.64, P<0.02) and ECW/ICW ratio (r=0.58, P<0.05), and almost significantly with R(ecf) (r=-0.51, P=0.08) and R(inf) (r=-0.52, P=0.07) estimated by MFBIA, but not with changes in weight or TBW. CONCLUSIONS: Use of icodextrin for the daytime dwell in APD results in improved fluid balance and blood pressure control compared with 2.27% glucose. MFBIA detected clinically important changes in fluid content in these patients.

Adult↗
PubMed1999

Low thrombogenicity of polyethylene glycol-grafted cellulose membranes does not influence heparin requirements in hemodialysis.

Heparin is the most commonly used anticoagulant for hemodialysis despite potentially serious side effects. Polyethylene glycol-grafted cellulose (PGC) membranes produce less activation of the coagulation cascade than cuprophane membranes. Anecdotally, we found some patients required a surprisingly low level of anticoagulation using these membranes. We compared the anticoagulant requirement of the PGC membrane with that of the cuprophane membrane in this randomized, prospective, crossover study. Sixty-three patients were randomized to treatment using either membrane, and heparin administration was progressively reduced to the lowest dose that prevented visible clotting in excess of that normally encountered. Patients underwent dialysis at this dose for 1 month, after which the heparin requirement and Kt/Vurea (1.162 x ln [urea pre/urea post]) were assessed. This process was then repeated for each patient using the other membrane, and the results were compared. Heparin administration during dialysis was reduced from a mean loading dose of 29.0 +/- 9.4 to 1.5 +/- 3.2 IU/kg for both membranes and a mean maintenance infusion of 14.0 +/- 6.7 to 0.77 +/- 1.6 IU/kg/h for both membranes (both P < 0.0001 v full anticoagulation; no difference between membranes). The Kt/Vurea was not significantly altered. Forty-six patients with PGC and 45 patients with cuprophane membranes underwent dialysis successfully without heparin during dialysis, and the other patients were using considerably reduced doses. Aspirin and warfarin had no effect on the heparin requirement. These results do not support the theory that PGC membranes have a lower anticoagulant requirement than cuprophane membranes; however, they suggest that dialysis can be performed successfully with much smaller anticoagulant doses than are currently in common use.

Anticoagulants↗
PubMed1999

Exaggerated systemic antibody response to mucosal Helicobacter pylori infection in IgA nephropathy.

Numerous studies in the literature report aberrant immune responsiveness in immunoglobulin A (IgA) nephropathy. However, all these studies investigate immune responses invoked by an artificially engineered antigen challenge. For the first time in IgA nephropathy, we report the systemic humoral responses generated as part of an active mucosal immune response against a common environmental pathogen, Helicobacter pylori (Hp). We studied 22 patients with IgA nephropathy and 9 controls without renal disease who were shown to be infected with Hp, using a 13C-urea breath test. Hp antigen-specific enzyme-linked immunosorbent assays were established to measure the anti-Hp IgA, IgG, and IgA and IgG subclass antibody levels. In addition, anti-Hp responses in the monomeric and polymeric (pIgA) fractions of serum IgA were measured after separation by gel filtration high-performance liquid chromatography. IgA nephropathy was associated with both a greater rate of IgA anti-Hp seropositivity (P < 0.05) and a more pronounced IgA anti-Hp antibody response (P < 0.01). In almost all cases, IgA anti-Hp was IgA1, and more than 90% was polymeric. There was no difference in the frequency of IgG anti-Hp seropositivity, but patients produced a much greater IgG anti-Hp response (P < 0.01). In addition, the IgG subclass responses were markedly different, with IgG1 predominant in controls and IgG2 and IgG3 the major subclasses produced in IgA nephropathy. We have shown an exaggerated systemic antibody response to mucosal infection caused by Hp in patients with IgA nephropathy, predominantly consisting of pIgA1, IgG2, and IgG3. This suggests that in IgA nephropathy, not only is pIgA1 production poorly controlled, but regulation of IgG isotype switching in response to mucosal pathogens is also deranged.

Adolescent↗
PubMed1999

Comparison of icodextrin and glucose solutions for the daytime dwell in automated peritoneal dialysis.

BACKGROUND: The sustained ultrafiltration achieved by icodextrin is more suited for the daytime dwell in automated peritoneal dialysis (APD) than glucose solutions. METHODS: Seventeen patients receiving APD underwent assessment using three different solutions for the daytime dwell: 2.27% glucose, 3.86% glucose and 7.5% icodextrin. Patients were then observed on icodextrin for a 6 month period. RESULTS: Daytime ultrafiltration was greater for 3.86% glucose (median 0.10, IQR 0.01 to 0.321) P<0.01 and icodextrin (median 0.26, IQR 0.14 to 0.361) P<0.001 than 2.27% glucose (median -0.19, IQR -0.54 to -0.081), with 3.86% glucose and icodextrin not being significantly different. Positive ultrafiltration occurred in 3/17 patients with 2.27% glucose, 13/17 patients with 3.86% glucose and 16/17 patients with icodextrin (chi2 P<0.0001). The difference in ultrafiltration of icodextrin and 3.86% glucose correlated with the 4 h dialysate/plasma creatinine ratio in a PET test (r = 0.51, P<0.05). Daytime Kt/V urea was greater for 3.86% glucose (median 0.27, IQR 0.20 to 0.48 per week, P<0.01) and icodextrin (median 0.31, IQR 0.27 to 0.49 per week, P<0.0001) than for 2.27% glucose (median 0.22, IQR 0.15 to 0.38 per week), with the difference between 3.86% glucose and icodextrin not reaching statistical significance (P = 0.06). Daytime creatinine clearance was greater for 3.86% glucose (median 10.2, IQR 6.9 to 13.61/week/1.73 m2, P<0.02) and icodextrin (median 12.1, IQR 9.3 to 15.71/week/1.73 m2, P<0.005) than for 2.27% glucose (median 8.8, IQR 4.9 to 11.91/week/1.73 m2). Daytime creatinine clearance was greater for icodextrin than for 3.86% glucose (P<0.005). The effects of icodextrin were sustained for the 6 month observation period. CONCLUSIONS: Icodextrin produced enhanced ultrafiltration and clearances compared with 2.27% glucose, without the exposure of the peritoneum to hypertonic glucose solutions.

Adult↗
PubMed1998

Assessment of ultrasound guided percutaneous ethanol injection and parathyroidectomy in patients with tertiary hyperparathyroidism.

BACKGROUND: Tertiary hyperparathyroidism continues to cause significant morbidity in patients with chronic renal failure. This is frequently resistant to medical management and may ultimately require a surgical parathyroidectomy. Recent studies have reported upon the technique of percutaneous ethanol ablation for both primary and tertiary hyperparathyroidism. In this study we report on a 5 year experience using ethanol injection and compare the results with surgical parathyroidectomy. METHODS: A prospective study in 39 patients with tertiary hyperparathyroidism, 25 were dialysis dependent and 14 had a functioning renal allograft. Twenty-two patients underwent percutaneous fine needle ethanol injection (PFNEI) and 17 underwent surgical parathyroidectomy. RESULTS: A > 30% reduction in intact parathyroid hormone (iPTH) was achieved in 11 of 22 patients undergoing PFNEI after a mean of 1.8 +/- 1.4 injections per gland. In four patients, symptomatic hyperparathyroidism recurred and they required further PFNEI or surgical parathyroidectomy at 17, 28, 46, and 48 months later. There was no significant reduction in iPTH in 11 patients following PFNEI after a mean of 2.5 +/- 1.3 injections per gland. They all required a subsequent surgical parathyroidectomy for symptomatic hyperparathyroidism. Four patients developed a laryngeal nerve palsy following PFNEI, two of which were permanent. Seventeen patients underwent successful surgical parathyroidectomy as a primary procedure. CONCLUSION: Whilst PFNEI is successful in primary hyperparathyroidism, when typically only one adenoma is present, the effectiveness of PFNEI is unpredictable and the long term results are poor compared with those of surgical parathyroidectomy in tertiary hyperparathyroidism. The procedure is not without complications and makes subsequent surgery more difficult. Therefore it can only be recommended for patients with a known single parathyroid gland such as patients in whom hyperparathyroidism has recurred following a previous surgical subtotal parathyroidectomy and who are unsuitable for further surgery.

Administration, Cutaneous↗