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Biomedical subjects

G Busnach

Publications and source records attributed to G Busnach.

At least 19 recordsLinked to original sources
PubMed2001

Effect of familial hypertension on glomerular hemodynamics and tubulo-glomerular feedback after uninephrectomy.

Familial hypertension, glomerular hemodynamic alterations, and dysregulation of tubulo-glomerular feedback (TGFB) have all been associated with the development of chronic renal failure. In the present study we evaluated renal and glomerular hemodynamics and TGFB responses in healthy kidney donors either with or without familial hypertension, before and after nephrectomy. Para-amino-hippurate plasma clearance (CPAH) and inulin plasma clearance (CInu) were measured in 15 kidney donors before and 1 year after nephrectomy. All subjects were normotensive and were kept in a sodium-replete state. Both clearances were measured after 40 min of constant infusion of PAH and Inu, as well as 20, 30, 50, and 60 min after the intravenous administration of acetazolamide (5 mg/kg). Glomerular hemodynamics were calculated by means of the Gomez formulae. Nephrectomy caused the expected decreases in CPAH and CInu and increase in the filtration fraction (all P < .0001). The decrease in renal resistances of the remaining kidney was greater at the afferent (-24%, P = .0075) than at the efferent arteriolar level (-17%, P < .0001). The TGFB activation was not altered by nephrectomy or by familial hypertension. Effective renal plasma flow (ERPF) decrease after TGFB activation appeared earlier than glomerular filtration rate (GFR) decrease before (P = .01), but not after, nephrectomy (P = .48). The presence of familial hypertension was associated with increased glomerular pressure (P = .0004). This study suggests that uninephrectomy in healthy human subjects causes a greater decrease in afferent arteriolar resistances, but that TGFB responses are not quantitatively altered. Familial hypertension is associated with a tendency toward higher glomerular pressures.

Arterioles↗
PubMed2000

Incidence and clinical characteristics of posttransplant lymphoproliferative disorders: report from a single center.

In the period 1973-1998, among 2139 allograft recipients treated with standard immunosuppression, posttransplant lymphoproliferative disorders (PTLD) developed in 19 patients (0.9%): one plasmacytic hyperplasia, two polymorphic PTLD, one myeloma, and 15 lymphomas. PTLD developed 1 year after transplantation (tx) in 14 patients. Five patients were diagnosed at autopsy, 2 were lost to follow up, 3 died before therapy could be instituted, and 1 patient has just started chemotherapy. Of the 8 evaluable patients, 2 received acyclovir and are alive in complete remission (CR) and 6 received chemotherapy +/- surgery. Of these 6, 4 died of lymphoma and/or infection, 1 died of unrelated causes in CR, and 1 is alive in CR. PTLD is a severe complication of tx, usually running an aggressive course which may preclude prompt diagnosis and treatment. Nevertheless, therapy is feasible and must be tailored on the histologic subtype. Seventy-four percent of patients were diagnosed with late-onset PTLD stressing the need for long-term follow up.

Acyclovir↗
PubMed1999

Effect of plasma cholesterol reduction by pravastatin on the functional properties of forearm arteries in hypercholesterolemic patients.

BACKGROUND AND AIM: Since functional properties in the vasculature of hypercholesterolemic subjects are impaired, a six-month pravastatin treatment (20 mg/die) was tested in an open design, on the impaired unstimulated forearm arterial compliance (Un-FAC(AUC)) of 14 asymptomatic type IIa familial hypercholesterolemic patients. In order to evaluate whether FAC(AUC) changes might be related to the extent of cholesterol reduction achieved, this evaluation was carried out in five severely hypercholesterolemic patients, undergoing LDL-apheresis. METHODS AND RESULTS: Arterial functional properties, i.e. FAC(AUC) responses to glyceryl trinitrate (GTN-FAC(AUC)) and acetylcholine (ACh-FAC(AUC), four patients) and the effects on rest and peak forearm blood flow and vascular resistance were evaluated on the non-dominant arm using plethysmographic methods, that also allow the direct assessment of the non-linear "compliance-blood pressure" curve. Selective LDL-apheresis was performed by using a dextran-sulphate column. Pravastatin effectively lowered plasma total (-16%, p = 0.002) and LDL cholesterol levels (-22%, p = 0.006 vs baseline). Rest and peak flow, basal and post ischemic vascular resistance were not affected as well as Un-FAC(AUC) and GTN-FAC(AUC). However, in the four hypercholesterolemic patients undergoing ACh infusion, there was an improvement in the ACh-FAC(AUC) of borderline statistical significativity (p = 0.056). LDL-apheresis reduced plasma total and LDL cholesterol levels by 55% and 59%, without affecting blood pressure. In this series of five patients Un-FAC(AUC) increased, the Un-FAC(AUC) rise being inversely related to the absolute reduction of plasma total (r = 0.92, p < 0.05) and LDL cholesterol (r = 0.89, p < 0.05) levels. CONCLUSIONS: In hypercholesterolemic patients a short-term hypocholesterolemic treatment with pravastatin, although able to improve the lipid profile, cannot alter significantly blood flow, vascular resistance, Un-FAC(AUC) and GTN-FAC(AUC). A possible selective improvement in the ACh-receptor-activated signal transduction pathway has been observed and the importance of a drastic reduction of cholesterol concentrations in order to affect the Un-FAC(AUC) is suggested.

Acetylcholine↗
PubMed1996

Intravenous gamma globulin in refractory thrombotic thrombocytopenic purpura.

We report the case of a young woman with refractory thrombotic thrombocytopenic purpura (TTP), treated with different therapies (standard therapy with plasma exchange, prostacyclin infusion, vincristine sulfate) and responding to these for brief periods. High-dose immunoglobulin (400 mg/kg/day for 5 days), on the other hand, yielded a complete response which has lasted for 14 months up to the time of this report.

Adult↗
PubMed1994

Removal of antiacetylcholine receptor antibodies by protein-A immunoadsorption in myasthenia gravis.

Myasthenia Gravis is an autoimmune disease in which autoantibodies to the acetylcholine receptor interfere with neuromuscular transmission. Plasma exchange is effective in temporarily relieving the symptoms of the disease, but for repeated use the lack of selectivity and need for replacement fluids (which increases the risk of contracting viral diseases) are important drawbacks. Staphylococcal protein A, a potent ligand for immunoglobulins, that interacts negligibly with other plasma proteins, appears to be an optimal candidate for removing antiacetylcholine receptor antibodies, which are mostly IgG. We treated three patients with severe immunosuppression-resistant myasthenia gravis with protein A immunoadsorption. Neurological impairment significantly improved in all patients. After immunoadsorption of 1.5-2 plasma volumes per session, the mean percentage reductions for serum IgG and specific autoantibodies were 71% and 82% respectively. No major side effects occurred. Protein A immunoadsorption appears to be a safe, efficient and effective alternative to plasmaexchange for selected myasthenic patients requiring prolonged apheresis.

Adult↗
PubMed1993

Clinical relevance of fractionation characteristics in cascade filtration.

Plasmapheresis performance is improved in the treatment of hyperviscosity syndromes with one of the several cascade filtration techniques (CF), intended for plasma fractionation and reinfusion of albumin-enriched plasma filtrate to the patients, avoiding the need for exogenous reinfusion solutions. A retrospective open analysis of 103 CF, performed by dead-end mode, in 14 patients with macroglobulinemia, cryoglobulinemia, multiple myeloma and other diseases, has been performed. Protein fractions removals have been calculated, normalized to the treatment of one plasma volume, compared in different macromolecular diseases and according to the different plasma fractionators employed. [table: see text] Protein removal is partially dependent of the surface area of the fractionator, but a wide variability has been reported, mainly depending on the underlying macromolecular disease.

Blood Viscosity↗
PubMed1992

Uremic inhibitors of erythropoiesis: a study during treatment with recombinant human erythropoietin.

The effects of increasing amounts of uremic sera (US) on the growth of erythroid progenitor cells [burst-forming unit erythroid (BFU-E)] collected from peripheral blood of normal subjects were evaluated to assess the potential role of uremic inhibitors of erythropoiesis during a treatment with recombinant human erythropoietin (r-HuEpo). US were collected from 8 patients on regular dialysis with marked anemia (Hb 6 +/- 0.5 g%) before and after a treatment with high doses of r-HuEpo (from 300 to 525 U/kg/week). Standard cultures for BFU-E were performed in alpha-metylcellulose with fetal calf serum (FCS) and 4 U/ml of r-HuEpo (Cilag, Ortho). In successive cultures, US were added at increasing amounts to the standard culture in order to assess a possible inhibitory effect on BFU-E growth. Finally, in order to assess a possible lack of stimulatory factors, we partially substituted FCS with US. The addition of US collected either before or after therapy with r-HuEpo to the standard culture had no effect on the growth of BFU-E. Vice versa, the number of cultured BFU-E decreased when FCS was partially substituted with US collected before r-HuEpo. This effect was not evident when FCS was partially substituted with US collected after r-HuEpo. No significant differences were recorded in the tested sera collected before and after therapy considering erythropoietin levels and amino acid levels. We hypothesized that some other factors with erythropoietic stimulatory activity (burst-promoting activity?) may be deficient in uremic patients with marked anemia and can be induced during therapy with r-HuEpo.

Adult↗
PubMed1991

Predictability of low-density lipoprotein levels during apheretic treatment of hypercholesterolaemia.

The efficiency and efficacy of low-density lipoprotein (LDL) apheresis performed with a dextran sulphate cellulose (DSC) regenerating unit were tested in five familial hypercholesterolaemic patients. LDL apheresis was repeated four times at both bi-weekly and weekly intervals, processing one plasma volume each time. The efficiency of the procedure (i.e., the extent of lipoprotein removal) was nearly identical with both schedules. Efficacy parameters, i.e., decreases of plasma total and LDL cholesterol (TC and LDL-C) and apo B, were highly correlated (r greater than 0.96) with preapheresis levels, allowing an accurate prediction of the absolute lipid removal in the single individual. Plasma triglycerides, high-density lipoprotein cholesterol, apo A-I and apo A-II recovered rather rapidly, reaching 91-96% of the pre-apheresis values in 48 hours; the recovery of TC, LDL-C and apo B was much slower, with a relatively rapid early phase (80% recovery after about 7 days) followed by a successive slower rise. This pattern was highly reproducible in the single patient, allowing the definition of a simple mathematical model for an accurate (error less than 20%) prediction of the individual process. Based on this model one can design the treatment schedule necessary to maintain lipid levels within the desired range in the single individual. The hypolipidaemic efficacy of DSC apheresis appears, otherwise, not to be dependent upon the procedure per se, but on other individual factors, e.g. the amount of removable lipoproteins and the rate of lipid recovery; both can be predicted with sufficient accuracy.

Apolipoproteins↗
PubMed1991

Management of lipoprotein-X accumulation in severe cholestasis by semi-selective LDL-apheresis.

Liver disorders characterized by prolonged bile stasis are often associated with the accumulation of an abnormal lipoprotein, lipoprotein-X (LP-X), in plasma. LP-X is separated in the low-density lipoprotein (LDL) density range, but lacks apolipoprotein B and does not interact with the LDL receptor; LP-X can cause hyperlipidemia, cutaneous xanthomas, and worsening of arterial disease. We report the case of a patient with severe cholestasis, markedly elevated plasma cholesterol levels (26.8 to 31.5 mmol/L), mainly due to a massive accumulation of LP-X in plasma, and diffuse xanthomas. To reduce the elevated cholesterol levels, the patient was given extracorporeal treatment aimed at removing atherogenic lipoprotein (LDL-apheresis). LDL-apheresis was performed at weekly or bi-weekly intervals, either by a semi-selective technique using filters with a defined pore diameter (double filtration, DF) or by a more selective technique using dextran-sulfate-cellulose (DSC) columns able to bind LDL. The semi-selective DF technique proved more effective than DSC, removing 48% of total cholesterol (compared to 30% with DSC), and lowering cholesterol levels to 11.1 mmol/L in 6 weeks. DF removed both LDL and LP-X from plasma, whereas DSC selectively decreased the LDL content. The reduction of plasma cholesterol levels was associated with a complete regression of the xanthomas, supporting DF apheresis as a first-choice treatment for patients with massive LP-X accumulation due to cholestasis.

Adult↗
PubMed1991

Impaired efficacy of selective LDL-apheresis in primary biliary cirrhosis.

Low-density lipoprotein apheresis (LDL-apheresis) was done with either cascade filtration (DF) or dextran sulfate cellulose adsorption (DSC) in a patient with primary biliary cirrhosis who developed severe dyslipidemia associated with cholestasis and accumulation of lipoprotein-X (LP-X). The extracorporeal treatment was initially performed weekly, and resulted in a sharp drop in total cholesterol from 1038 to 430 mg/dl. During the next four months the patient was treated every 10-15 days, and pre-apheresis cholesterol levels were maintained between 438 and 505 mg/dl, until an orthotopic liver transplantation was successfully performed. With semi-selective DF a mean 47.1% of total cholesterol was removed per procedure compared to 30.0% with DSC, although the volume of treated plasma was 38.0 vs 49.9 ml/kg body weight. The changes in plasma cholesterol levels during DSC and DF showed that the kinetics of cholesterol removal were similar with both techniques, but the efficacy differed; DF removed both LDL and LP-X from plasma, whereas DSC selectively lowered the LDL content. Cascade filtration may therefore be considered as a first-choice treatment for patients with LP-X accumulation due to cholestasis.

Adult↗
PubMed1990

Prothrombin-antibody coexistent with lupus anticoagulant (LA): clinical study and immunochemical characterization.

The patient is a 23 y.o. man with acute nephritis and bleeding at presentation. Laboratory data consistent with the diagnosis of systemic lupus erythematosus. A lupus anticoagulant was found: tissue thromboplastin inhibition test (TTIT) ratio 3.4; diluted Russell viper venom (DRVV) ratio 2.6. Hypoprothrombinemia (FII:C less than 1%; FIIR:Ag 5%) was present; prothrombin survival time (FII concentrate infusion 60 U/kg): t1/2 approximately to 9 hours. A prothrombin antibody was identified: it is not neutralizing but forms an immunecomplex with prothrombin. The antibody was characterized as IgG2, IgA, k, lambda. The prothrombin survival time indicates that the hypoprothrombinemia is due to the clearance of the prothrombin-antiprothrombin complex in vivo.

Adult↗