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Renal transplantation using live donors with vascular anomalies: a salvageable surgical challenge.
Saudi J Kidney Dis Transpl. 2008 Jul-Aug; 19(4): 554-8
Singh PB, Goyal NK, Kumar A, Dwivedi US, Trivedi S, Singh DK, Prakash J
Renal transplantation is an established mode of management for patients with end-stage renal disease (ESRD). In India, majority of the patients with ESRD depend upon live donors for renal transplantation and renal vascular anomalies are commonly seen in these potential donors. We present our experience in renal transplantation using donors with vascular anomalies. During the period between 2001 and 2004, we performed 36 live related donor renal transplantations. All study patients had only one donor each, with compatible blood group. Ten of the donors had vascular anomalies. Three had bilateral double arteries, one had double left and single right renal artery, one had bilateral triple arteries, one had triple arteries on left and double arteries on right side, of which one had early branching, two had bilateral early branching of arteries, and two other cases had double renal veins. Open donor nephrectomy was performed in all the cases. End-to-side anastomosis with external iliac vein and artery of the recipient was performed by the parachuting technique. Eight kidneys had immediate diuresis after transplantation. In two kidneys, diuresis started 2-3 hours after administration of 120 mg of furosemide. All patients had serum creatinine ranging between 0.9 and 1.8 mg/dl by the 10th post-operative day. Follow-up of these cases have varied from one month to two years. In the current scenario, multiple arteries in the donor are no longer considered relative contraindications for renal transplantation. With good surgical skill and experience in bench surgery, all such donors can be accepted. Use of external iliac artery for anastomosis with the technique of parachuting makes the procedure easy and safe.
Renal Blood Flow and Dynamic Autoregulation in Conscious Mice.
Am J Physiol Renal Physiol. 2008 Jun 25;
Iliescu R, Cazan R, McLemore Jr GR, Venegas-Pont M, Ryan MJ
Autoregulation of renal blood flow (RBF) occurs via myogenic and tubuloglomerular feedback (TGF) mechanisms that are engaged by pressure changes within preglomerular arteries and by tubular flow and content, respectively. Our understanding of autoregulatory function in the kidney largely stems from experiments in anesthetized animals where renal perfusion pressure is precisely controlled. However, normally occurring variations in blood pressure are sufficient to engage both myogenic and TGF mechanisms making the assessment of autoregulatory function in conscious animals of significant value. To our knowledge, no studies have evaluated the dynamics of RBF in conscious mice. Therefore, we used spectral analysis of blood pressure and RBF and identified dynamic operational characteristics of the myogenic and TGF mechanisms in conscious, freely moving mice instrumented with ultrasound flow probes and arterial catheters. The myogenic response generates a distinct resonance peak in transfer gain at 0.31+/-0.01 Hz. Myogenic-dependent attenuation of RBF oscillations, indicative of active autoregulation, is apparent as a trough in gain below 0.3 Hz (-6.5+/-1.3 dB) and a strong positive phase peak (93+/-9 deg), which are abolished by amlodipine infusion. Operation of TGF produces a local maximum in gain at 0.05+/-0.01 Hz and a positive phase peak (62.3+/-12.3 deg), both of which are eliminated by infusion of furosemide. Administration of amlodipine eliminated both myogenic and TGF signature peaks, whereas furosemide shifted the myogenic phase peak to a slower operational frequency. These data indicate that myogenic and TGF dynamics may be used to investigate the effectiveness of renal autoregulatory mechanisms in conscious mice. Key words: myogenic, tubuloglomerular feedback, mouse, renal blood flow, dynamics.
Evaluation of renal oxygenation in rat by using r2' at 3-T magnetic resonance initial observation.
Acad Radiol. 2008 Jul; 15(7): 912-8
Yang X, Cao J, Wang X, Li X, Xu Y, Jiang X
RATIONALE AND OBJECTIVES: We sought to initially evaluate the feasibility of R2' on a 3-T magnetic resonance (MR) scanner for assessment of renal oxygenation changes following administration of furosemide in rats. MATERIALS AND METHODS: Eight intact male Wistar rats were involved in experimental group. The experiment was performed at a 3-T MR scanner using a multiple gradient-echo (mGRE) sequence for R2* map and a multiecho fast spin-echo (FSE) sequence for R2 map. R2' values of cortex and medulla were calculated using the equation R2* = R2 + R2'. The values of R2 and R2* were measured and R2' was calculated before and after administration of furosemide, and the changes (delta values) were calculated. RESULTS: Both R2* and R2 values decreased significantly after administration of furosemide (P < .001) in both the cortex and medulla. DeltaR2* in the medulla was significantly higher than in the cortex (P < .05). DeltaR2 was not significantly different between the cortex and medulla (P > .05). The baseline R2' value was 12.13 +/- 0.59 1/s in the cortex and 19.52 +/- 3.44 1/s in the medulla. R2' value decreased significantly in the medulla after administration of furosemide (P < .05), but there was no significant difference in the cortex before and after administration of furosemide (P > .05). CONCLUSION: R2' may be more appropriate than R2* to indicate the change of oxygenation after administration of furosemide in intact rats at 3-T MR. Further studies are needed for both intact animals and experimental models in comparison with non-MR imaging methods to validate this initial observation.
Severe keloids caused by hydrogen cyanide injury: a case report.
Cutan Ocul Toxicol. 2008; 27(2): 97-101
Jian X, Guo G, Ruan Y, Lin D, Zhao B
The purpose of this study was to report severe keloids caused by hydrogen cyanide injury. Hydrogen cyanide poisoning is still a problem as an occupational disease in China. We report a 37-year-old man with severe hydrogen cyanide poisoning. The patient fell on the floor after inhalation of hydrogen cyanide and was burned on his back by hydrocyanic acid. Sequential treatment included amyl nitrite by inhalation, intravenous sodium nitrite 3%, and intravenous sodium thiosulfate 25%. Other treatment consisted of incision of the trachea, mannitol and furosemide, antibiotics, and nutrient support measures. The patient also received hyperbaric oxygen therapy; during the first treatment, he became apneic and cardiopulmonary resuscitation was supplied in the hyperbaric oxygen chamber. He eventually recovered, but a large amount of keloids developed on his back and buttocks.
Eur J Heart Fail. 2008 Jun 17;
Macchia A, Monte S, Pellegrini F, Romero M, D'Ettorre A, Tavazzi L, Tognoni G, Maggioni AP
AIMS: To assess the relationship between depression and clinical outcomes among elderly patients with heart failure (HF) in a community setting. METHODS AND RESULTS: To identify patients with HF and depression we used record linkage analysis of hospital discharge records, prescription databases and vital statistics. All consecutive patients aged>/=60 years in 6 Local Health Authorities in Italy were included. HF was defined as either: 1) hospital discharge with HF diagnosis (ICD-9: 428) and/or 2) chronic treatment for HF identified as concomitant (within 45 days) prescription of any combination of ACE inhibitors, digoxin, furosemide, bisoprolol, carvedilol, spironolactone, ARB-blockers. Depression was identified from exposure to psychotropic drugs before HF diagnosis. Cox proportional hazards models adjusted for major confounders were used. To adjust for potential residual known confounders, a propensity score analysis was performed. Sensitivity and subgroup analysis were used to demonstrate the consistency or robustness of the results. 48,117 patients with HF were identified. Of these, 3328 (6.9%) were treated for depression. Among patients with HF, those with depression were significantly older, and more likely to be women with a previous stroke. Depression significantly worsened major outcomes including all cause mortality [HR (95%CI); 1.20 (1.08-1.33)] and the composite of stroke/TIA/AMI [1.23 (1.13-1.34)]. Patients with depression had no increased risk of rehospitalisation for HF. Propensity scores and subgroup analysis confirmed these findings. CONCLUSION: Among elderly patients with HF, depression was independently associated with poor clinical outcomes mostly due to an increase in vascular events.
Clinical relevance of pharmacokinetics and pharmacodynamics in cardiac critical care patients.
Clin Pharmacokinet. 2008; 47(7): 449-62
Pea F, Pavan F, Furlanut M
Pharmacokinetics is a discipline aimed at predicting the best dosage and dosing regimen for each single drug in order to ensure and maintain therapeutically effective concentrations at the action sites. In cardiac critical care patients, various pathophysiological conditions may significantly alter the pharmacokinetic behaviour of drugs. Gastrointestinal drug absorption may be erratic and unpredictable in the early postoperative period, and so patients may be unresponsive to oral therapy; thus the intravenous route should be preferred for life-saving drugs whenever feasible. Variations in the extracellular fluid content as a response to the trauma of surgery and the fluid load or significant drug loss through thoracic drainages may significantly lower plasma concentrations of extracellularly distributed hydrophilic antimicrobials (beta-lactams, aminoglycosides and glycopeptides). Drug metabolism may be altered by the systemic inflammatory response and/or multiple organ failure and/or drug-drug pharmacokinetic interactions that can potentially occur during polytherapy, especially in immunosuppressed cardiac transplant patients. Instability of renal function may promote significant changes in body fluid concentrations of renally eliminated drugs, even in a brief period of hours. Finally, the application of extracorporeal circulation by means of cardiopulmonary bypass may significantly alter the disposition of several drugs during the operation because of acute haemodilution, hypoalbuminaemia, hypothermia and/or adsorption to the bypass equipment. Accordingly, to avoid either overexposure and the consequent increased risk of toxicity or underexposure and the consequent risk of therapeutic failure in critically ill cardiac patients, the dosing regimens of several drugs are expected to be significantly different from those suggested for clinically stable patients. Additionally, therapeutic drug monitoring may be helpful in the management of drug therapy and should be routinely used to guide individualized dose adjustments for (i) immunosuppressants whenever cytochrome P450 3A4 isoenzyme inhibitors (e.g. macrolide antibacterials, azole antifungals) or inducers (e.g. rifampicin [rifampin]) are added to or withdrawn from the regimen; and (ii) glycopeptide and aminoglycoside antibacterials whenever haemodynamically active agents (such as dopamine, dobutamine and furosemide [frusemide]) are added to or withdrawn from the regimen, and also whenever significant changes of haemodynamics and/or of renal function occur.
Oscillating Cortical Thick Ascending Limb Cells at the Juxtaglomerular Apparatus.
J Am Soc Nephrol. 2008 Jun 18;
Komlosi P, Banizs B, Fintha A, Steele S, Zhang ZR, Bell PD
While studying the intracellular calcium dynamics in cells of the macula densa, the observation was made that tubular epithelial cells located near the macula densa and associated with the renal arterioles exhibit spontaneous Ca(2+) oscillations. In this study, the cortical thick ascending limb-distal tubule, with attached glomerulus, was isolated and perfused. At a low luminal sodium chloride concentration, Ca(2+) oscillations at a frequency of 63 mHz were observed in tubular cells that were within 100 microm of the macula densa plaque using four-dimensional multiphoton microscopy and wide-field fluorescence microscopy with fura-2. The Ca(2+) oscillations were absent in the macula densa cells. Spontaneous oscillations in basolateral membrane potential suggested that Ca(2+) oscillations occurred, at least in part, through depolarization-induced increases in Ca(2+) entry. The amplitude of these Ca(2+) oscillations was significantly enhanced by the activation of the Ca(2+)-sensing receptor. Increasing the luminal sodium chloride concentration or luminal flow resulted in a significant increase in both the amplitude of Ca(2+) oscillations and the intracellular Ca(2+) concentration in perimacular cortical thick ascending limb cells. In addition, luminal furosemide attenuated the [NaCl]L-dependent changes in intracellular Ca(2+) concentration, but hydrochlorothiazide had no effect. These findings demonstrate that tubular epithelial cells at the perimeter of the macula densa exhibit spontaneous oscillations in intracellular Ca(2+) concentration, enhanced by tubular flow and luminal sodium chloride. These oscillatory patterns may play a role in juxtaglomerular signaling.
J Physiol. 2008 Jun 12;
De Gobbi JI, Menani JV, Beltz TG, Johnson RF, Thunhorst RL, Johnson AK
The inflation of an intravascular balloon positioned at the superior vena cava and right atrial junction (SVC-RAJ) reduces sodium or water intake induced by various experimental procedures (e.g., sodium depletion; hypovolemia). In the present study we investigated if the stretch induced by a balloon at this site inhibits a rapid onset salt appetite, and if this procedure modifies the pattern of immunohistochemical labeling for Fos protein (Fos-ir) in the brain. Male Sprague-Dawley rats with SVC-RAJ balloons received a combined treatment of furosemide (Furo - 10 mg/kg bw) plus a low dose of the angiotensin-converting enzyme inhibitor captopril (Cap - 5 mg/kg bw). Balloon inflation greatly decreased the intake of 0.3 M NaCl for as long as the balloon was inflated. Balloon inflation over a 3 h period following Furo/Cap treatment decreased Fos-ir in the organum vasculosum of the lamina terminalis and the subfornical organ and increased Fos-ir in the lateral parabrachial nucleus and caudal ventrolateral medulla. The effect of balloon inflation was specific for sodium intake because it did not affect the drinking of diluted sweetened condensed milk. Balloon inflation and deflation also did not acutely change mean arterial pressure. These results suggest that activity in the forebrain circumventricular organs and in hindbrain putative body fluid/cardiovascular regulatory regions is affected by loading low pressure mechanoreceptors at the SVC-RAJ, a manipulation that also attenuates salt appetite.
J Nucl Med. 2008 Jun 13;
Schlotmann A, Clorius JH, Rohrschneider WK, Clorius SN, Amelung F, Becker K
The significance of delayed tissue tracer transit (TTT) of (99m)Tc-mercaptoacetyltriglycine ((99m)Tc-MAG3) has not been systematically evaluated in hydronephrosis. We sought to demonstrate that delayed TTT accompanies both functional decline and histomorphologic restructuring. METHODS: Twenty 2- to 3-mo-old piglets with surgically induced partial unilateral ureteral stenosis were examined with magnetic resonance urography (MRU) to evaluate morphology and with (99m)Tc-MAG3 diuretic renography (DR) to determine single-kidney function (SKF), evaluate the response to furosemide stimulation (RFS), and assess TTT. All animals had DR and MRU before and after surgery and a third DR after surgery. Piglets were sacrificed after the final DR for renal histology. A total histologic score (THS) was generated. RESULTS: Preoperative DR demonstrated nonobstructive RFS, timely TTT, and balanced SKF in all 20 kidneys. After ureteral ligature, MRU demonstrated pelvic dilatation in all piglets. The postoperative DRs revealed 12 kidneys with delayed TTT in one or both follow-ups. In these 12 kidneys, the SKF declined from 51% +/- 4% to 18% +/- 14%, and the THS was 9.0 +/- 4.0. Three kidneys always had timely TTT, balanced SKF, and a THS of 1.8 +/- 0.3. The contralateral, nonoperated kidneys had timely TTT and a THS of 1.2 +/- 0.9. Postoperative scintigrams showed that 3 of 8 kidneys (38%) with an obstructive RFS had timely TTT, which demonstrates that TTT and RFS are not equivalent. CONCLUSION: In hydronephrosis, a delayed TTT of (99m)Tc-MAG3 accompanies both functional decline and histomorphologic restructuring in obstruction. According to the literature, a delayed TTT is determined by the filtration fraction of the kidneys and appears to identify an obstruction-mediated upregulated renin-angiotensin system.
[The quantitative measurement of the echogenicity of the renal parenchyma]
Praxis (Bern 1994). 2008 Mar 19; 97(6): 297-303
Tuma J, Schwarzenbach HR, Nováková B, Jungius KP, Kuchta M
The qualitative assessment of the echogenicity of the renal cortex and the medulla is one of the most important diagnostic criteria in the assessment of diffuse renal parenchymal disease. It is of interest to complete this assessment by quantitative data. The echogenicity of the cortex and medulla was quantitatively analysed in digitized images. The coefficient of variation of repeated measurements was 0.83% and the coefficient of variation made by two different individuals was 2.03%. The influence of furosemide on the echogenicity of the renal parenchyma was measured in 4 healthy adults. The echogenicity of the renal cortex is after 3 and 6 min significantly increased, while the echogenicity of the medulla remained unchanged. Our study shows that a precise measurement of echogenicity in renal parenchyma is possible. Under the influence of furosemide there will be a significant increase in the echogenicity of the renal cortex.