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Asher Korzets

Publications and source records attributed to Asher Korzets.

17 recordsLinked to original sources
PubMed2006

Effect of hemodialysis on the thickness of vocal folds: a possible explanation for postdialysis hoarseness.

BACKGROUND: Determining the dry weight of chronically hemodialysed patients is a common problem. Patients on intermittent hemodialysis often experience transient hoarseness at the end of dialysis. The vocal folds may be affected by the hydration state. AIM: To test the hypothesis that postdialysis hoarseness may be related to changes in the thickness of the vocal folds. METHODS: Twenty-five stable chronic hemodialysis patients underwent endoscopic nasopharyngeal laryngoscopy before and after dialysis. Pictures of the vocal folds were taken and the folds were measured using computer software. Eighteen vocal folds from 16 patients were technically adequate for analysis. The change in the width/length ratio of the vocal folds (W/L) was used as a measurement of the folds' thickness. RESULTS: W/L decreased from 0.175 +/- 0.011 before dialysis to 0.152 +/- 0.009 after dialysis (p < 0.01, mean reduction 10.9 +/- 3.8%). Patients' weight decreased by 4.7 +/- 0.3% (p < 0.0001), systolic blood pressure decreased by 15.0 +/- 3.1% (p < 0.001), diastolic blood pressure decreased by 13.0 +/- 3.6% (p < 0.01), and mean blood pressure decreased by 14.1 +/- 3.1% (p < 0.001). Sixty percent of the patients had postdialysis hoarseness, and in 72% of the patients a decrease in the vocal folds' thickness was observed. CONCLUSIONS: Chronic hemodialysis patients may experience transient postdialysis hoarseness, and a decrease in the vocal folds' thickness. The latter may result from dehydration.

Adult↗
PubMed2005

Spontaneous DNA repair in human mononuclear cells is calcium-dependent.

Spontaneous DNA repair in peripheral blood mononuclear cells (PBMC) has been recently described. The aim of this study was to evaluate whether spontaneous DNA repair is Ca(2+)-dependent, as in vitro-stimulated DNA repair. Spontaneous DNA repair in PBMC was measured in a 1mM Ca2+ medium. The effect of extracellular Ca2+ chelation by EGTA, intracellular Ca2+ chelation by bapta-AM, and Ca2+ loading by the ionophore A23187 was examined. The signal transduction pathway was evaluated by inhibiting protein tyrosine kinase with genistein, calmodulin with W7, and calcineurin with cyclosporin A and tacrolimus. Extracellular Ca2+ chelation had no effect on spontaneous DNA repair, while both intracellular chelation and calcium overloading inhibited the DNA repair. Inhibition of protein tyrosine kinase, calmodulin or calcineurin reduced DNA repair. In conclusion, spontaneous DNA repair is mainly Ca(2+)-dependent at a narrow range of intracellular Ca2+ concentrations. The signal transduction cascade includes protein tyrosine kinase, calmodulin, and calcineurin.

Calcimycin↗
PubMed2005

Non-occlusive mesenteric ischemia in chronically dialyzed patients: a disease with multiple risk factors.

BACKGROUND: Non-occlusive mesenteric ischemia (NOMI) can be a fatal complication in dialysis patients. Intradialytic hypotension is usually the precipitating factor. The occurrence of 16 cases in 5 years (1998-2002), compared with only 4 in previous years, led us to investigate other risk factors contributing to NOMI. A control group of stable hemodialysis patients was used for comparison. RESULTS: 20 patients were studied: 17 diagnosed surgically, and 3 clinically. The mean age was 70.8 +/- 1.8 years, and the male:female ratio 7:13. Nineteen patients were on hemodialysis. Clinically overt atherosclerosis was present in 17 patients. Preceding dialysis-associated hypotension was identified in all patients studied and access thrombosis in 6 patients. In all patients, abdominal pain was the presenting symptom. Initial abdominal examination was unimpressive in 16 patients. The hemoconcentration, leukocytosis and metabolic acidosis were the most prominent laboratory findings. 5/11 abdominal sonograms showed intestinal pathology. 2/3 angiographies were diagnostic. Three patients responded to early fluid challenge and did not require surgery. Pathology was related to the area of the superior mesenteric artery in all 15 patients operated. Twelve (60%) patients died from the event. The 1-year mortality rate was 17/20 patients (85%). Possible contributing factors, other than dialysis-associated hypotension, included: high-dose recombinant human erythropoietin (rhEPO) therapy (179 +/- 35 vs. 116 +/- 10 U/kg/week in the control group, p < 0.05); metastatic calcifications (abdominal aorta 14/14, aortic valve 11/18; medial calcification of mesenteric arteries in 2/11 pathology specimens); digoxin, and hypoalbuminemia. CONCLUSIONS: The increased incidence of NOMI in dialysis patients may be related to overly aggressive rhEPO therapy and the unsuspected presence of mesenteric arterial medial calcifications. Identification of patients at risk, prevention of intradialytic hypotension and a controlled increase in dry weight may help to reduce the incidence of NOMI in chronically dialyzed patients.

Aged↗
PubMed2004

Ischemic optic neuropathy in dialyzed patients: a previously unrecognized manifestation of calcific uremic arteriolopathy.

Two patients with end-stage renal disease and on long-term hemodialysis presented with hypotension and an acute unilateral loss of vision. A diagnosis of anterior ischemic optic neuropathy (AION) was made quickly, but despite high-dose steroid therapy, significant vision was not recovered. Temporal artery biopsy results showed extensive medial calcification. The possibility that hypotension, when coupled with calcific uremic arteriolopathy in arteries supplying the optic nerve head, will lead to AION in dialyzed patients is discussed. A short review of AION in the dialysis population is given.

Aged↗
PubMed2004

Air in the liver?

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Embolism, Air↗
PubMed2003

Lower extremity amputations in chronically dialysed patients: a 10 year study.

BACKGROUND: Lower limb critical ischemia is a major problem in dialysed patients. OBJECTIVE: To evaluate the results of revascularization procedures, amputations and prosthetic rehabilitation in dialysed amputees. METHODS: In this retrospective study we examined the charts of selected dialysis patients. Forty-eight patients had undergone major amputation (4.5% of the dialysis population), and 24 patients entered the rehabilitation program. Widespread arterial calcification was common and led to falsely elevated ankle-brachial pressure indices in 9 of 14 limbs. Eight patients underwent revascularization. Subsequent major amputation was carried out 4 +/- 4.5 months after the revascularization (above knee in 5 patients and below knee in 3). Of the 16 patients who underwent primary amputation, only 2 were above-knee amputees. Seven patients with toe or metatarsal amputation went on to a major amputation 1.8 +/- 1.2 months after the distal amputation. RESULTS: No differences were found between diabetic and non-diabetic patients regarding the number of revascularization operations performed, the level of major amputation, or overall survival. Prosthetic rehabilitation was considered successful in 12 patients, partially successful in 8, and failed in 4 patients. Patient survival time was shortest in those patients with failed rehabilitation. A younger age confirmed favorable rehabilitation results, while long-standing diabetics and bilateral amputees were poor rehabilitation candidates. Patients who underwent primary amputation had more successful rehabilitation. A comparison between 24 dialysed amputees and 138 non-uremic amputees revealed similar rehabilitation results, although hospitalization time was longer in the dialysed patients. CONCLUSIONS: Early definitive therapy is essential when dealing with critical ischemia. After diagnostic angiography, proximal revascularization should be performed where feasible. Primary amputation is indicated in patients with extensive foot infection or gangrene. Prosthetic rehabilitation is warranted in most dialysed amputees.

Adult↗
PubMed2003

The "DRIL" procedure--a neglected way to treat the "steal" syndrome of the hemodialysed patient.

BACKGROUND: The ischemic "steal" syndrome complicates angio-access in a growing number of hemodialysed patients. Until now, operative attempts (fistula ligation or banding) to treat this problem have met with only limited success. OBJECTIVE: To assess the results of DRIL (distal revascularization-interval ligation) procedure in treating the "steal" syndrome. METHODS: A retrospective review (1996-2002) was conducted of all 11 patients who underwent the DRIL procedure in two tertiary care hemodialysis units. RESULTS: Two patients were excluded because of inadequate medical documentation. All of the nine patients remaining suffered from overt atherosclerotic disease, six had diabetic nephropathy and four were smokers. The arteriovenous access, which led to the "steal" syndrome, was proximally located in all (antecubital in 8, thigh area in 1). "Steal" symptoms included hand pain, paraesthesia, neurologic deficits and gangrenous ulcers. DRIL was technically successful in all patients. There were no perioperative deaths. Immediate and complete relief of pain was achieved in eight of the nine patients. One patient with gangrene later required a transmetacarpal amputation. No patient required hand amputation. During follow-up (range 1-26 months) hemodialysis was continued uninterruptedly using the problematic AVA in all patients. Thrombosis occurred in the AVA in only two patients after the DRIL procedure at 9 and 24 months postoperatively, respectively. Three patient deaths were unrelated to the DRIL. CONCLUSIONS: In selected patients the DRIL procedure is a safe and effective way to treat the "steal" syndrome. AVA patency is not compromised by this operation. Preoperative angiography, before and after manual compression of the AVA, is crucial for the proper selection of patients who will benefit most from the DRIL procedure.

Aged↗
PubMed2002

The contribution of an arteriovenous access for hemodialysis to left ventricular hypertrophy.

BACKGROUND: The long-term isolated contribution of hemodialysis arteriovenous access (AVA) to cardiac hemodynamics has not been previously investigated in a prospective manner. METHODS: Twelve predialysis patients were studied before and 1 and 3 months after creation of a primary AVA. Evaluation included relevant clinical parameters, echocardiographic studies, and hemodynamic hormones. RESULTS: After creation of an AVA, there was no change in patient weight, blood pressure or hemoglobin level. Cardiac index increased and systemic vascular resistance decreased. Left ventricular mass (LVM) corrected to height increased from 63.8 +/- 5.5 to 68.9 +/- 4.9 g/m(2.7) at 1 month (P = 0.05) and 72.5 +/- 8.9 g/m(2.7) at 3 months (P < 0.05). This increase in LVM was accounted for mostly by an increase in interventricular septal thickness, whereas left ventricular end-diastolic diameter and posterior wall thickness did not change. The incidence of left ventricular hypertrophy (LVH) increased from 67% at baseline to 83% and 90% at 1 and 3 months, respectively. Left atrial area increased from 17.6 +/- 1.0 cm(2) at baseline to 19.7 +/- 1.3 cm(2) at 1 month (P < 0.01) and 20.2 +/- 1.2 cm(2) at 3 months (P < 0.05). Early diastolic transmitral flow increased from 68.0 +/- 4.2 cm/s at baseline to 85.6 +/- 7.3 and 89.2 +/- 6.5 cm/s at 1 and 3 months, respectively (P < 0.01). Inferior vena cava diameter increased at 1 month and did not change at 3 months. Plasma atrial natriuretic polypeptide levels increased from 268 +/- 35 pg/mL (87 +/- 11 pmol/L) at baseline to 461 +/- 63 pg/mL (150 +/- 20 pmol/L) at 1 month (P < 0.01) and 610 +/- 96 pg/mL (198 +/- 31 pmol/L) at 3 months (P < 0.01). Plasma renin activity and serum aldosterone levels decreased. Plasma angiotensin II, angiotensin-converting enzyme, and endothelin levels did not change. CONCLUSION: Creation of a hemodialysis AVA is independently associated with further progression of already existing LVH.

Adult↗
PubMed2002

DNA repair in mononuclear cells: role of serine/threonine phosphatases.

Treatment with cyclosporin A (CsA) in kidney-transplant recipients is associated with reduced DNA repair and enhanced cancer incidence. CsA is an inhibitor of the serine/threonine phosphatase calcineurin, also termed PP2B, which is a Ca(2+)/calmodulin-dependent phosphatase. In this study we sought to elucidate the role of calcineurin in DNA repair using CsA and tacrolimus; examine whether UV-induced DNA repair is associated with dephosphorylation; and investigate whether phosphatases other than calcineurin are active in DNA repair, in light of the fact that calcineurin inhibition only partially suppressed DNA repair. Peripheral blood mononuclear cells from healthy donors were used. In vitro, we assayed UV-induced DNA repair by measuring the incorporation of tritiated thymidine in UV-irradiated cells. We gauged phosphatase activity indirectly by measuring free inorganic phosphate (Pi) excreted into the medium. The phosphatase assay was performed under the same conditions and in parallel to the DNA-repair assay. Tacrolimus, like CsA, inhibited DNA repair in a dose-dependent fashion. DNA repair was associated with production of Pi, which correlated with the number of cells performing DNA repair. Phosphatase activity increased after UV irradiation. DNA repair correlated directly with phosphatase activity, whereas CsA reduced both DNA repair and Pi production. Inhibition of calmodulin by trifluoperazine and W7 [N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide] reduced DNA repair in part. We investigated the role of the Ca(2+)-independent phosphatases PP1 and PP2A using specific inhibitors. Calyculin A, which inhibits both phosphatases, reduced DNA repair. Endothall, a PP2A inhibitor, had no effect on DNA repair. Okadaic acid, which is mostly a PP2A inhibitor but also a weak inhibitor of PP1, reduced DNA repair only slightly. We suggest that DNA repair is mediated by way of Ca(2+)-dependent and Ca(2+)-independent pathways, with calcineurin and PP1 being the respective phosphatases involved in each pathway.

Calcineurin↗
PubMed2002

Using the automated biopsy gun with real-time ultrasound for native renal biopsy.

BACKGROUND: The use of an automated biopsy system for renal biopsy has recently gained popularity, but its safety in single functioning kidneys is unclear. OBJECTIVE: To report our experience with the automated system for closed renal biopsy during a 5 year period. METHODS: Eighty-five patients underwent percutaneous native renal biopsy with the automated biopsy gun (16G needle) under real-time ultrasound. They were chronologically divided into two groups: 41 patients (group A), using an older ultrasound machine; and 44 patients (group B), using a newer ultrasound machine. Nine patients biopsied with a manual 14G Tru-cut needle served as the control (group C). RESULTS: The number of "attempted" passes at the kidney was 4.0 +/- 0.1 in group B, 4.7 +/- 0.3 in group A (P < 0.05 vs. group B), and 5.8 +/- 0.5 in group C (P < 0.01 vs. group B). The number of successful passes did not differ (3.3 +/- 0.1, 3.3 +/- 0.1, 3.1 +/- 0.2). The ratio of "attempted/successful" was 1.28 +/- 0.07 in group B, 1.95 +/- 0.38 in A, and 1.90 +/- 0.21 in C (P < 0.01 vs. B). The number of glomeruli obtained was similar in the three groups. Adequate tissue was obtained in 95%, 98%, and 100%, respectively. Hemoglobin decreased by 4.3 +/- 1.1% in group B, 6.9 +/- 1.3% in group A, and 11.3 +/- 1.8% in group C (P < 0.05 vs. B). Perinephric/subcapsular hematoma occurred in 5 patients (11.4%) in group A (2 taking aspirin), in 2 patients (4.9%) in group B, and in none in group C. The necessity for blood transfusion post-biopsy was similar in all groups. Four of five patients with single functioning kidneys (one in group A and four in group B) had uneventful biopsies, and adequate tissue was obtained in three. CONCLUSIONS: The use of the automated biopsy gun is effective, safe and has a low rate of major complications. It may be used safely in single functioning kidneys.

Adolescent↗