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1.
Med Princ Pract ; 27(4): 367-371, 2018.
Article in English | MEDLINE | ID: mdl-29723861

ABSTRACT

OBJECTIVE: Beta thalassaemia minor is a common genetic disorder without any characteristic symptoms except mild anemia. It is found to be associated with some cardiovascular risk factors such as insulin resistance and diabetes mellitus. The renal resistive index (RRI) is a measure of renal arterial resistance to blood flow. The aim of this study was to evaluate the RRI in subjects with beta thalassemia minor (BTM). SUBJECTS AND METHODS: A total of 253 subjects were included in this cross-sectional study. The study group consisted of 148 subjects with BTM and the control group consisted of 105 healthy subjects. BTM was diagnosed by a complete blood count and hemoglobin electrophoresis. Blood pressure measurement and biochemical tests were performed. The RRI of all subjects was measured using renal Doppler ultrasonography. RESULTS: Subjects with BTM had lower renal resistive indices compared to healthy subjects (0.58 ± 0.04 vs. 0.60 ± 0.06, p = 0.0016). Additionally, the RRI levels of subjects with BTM were correlated with systolic blood pressure (p = 0.017, r = 0.194). CONCLUSION: In this study, lower RRI were found in subjects with BTM. This may be associated with a decreased vascular resistance and blood viscosity in these subjects.


Subject(s)
Kidney/physiopathology , Renal Blood Flow, Effective/physiology , beta-Thalassemia/physiopathology , Adult , Aged , Blood Pressure/physiology , Case-Control Studies , Female , Humans , Hypotension/complications , Kidney/diagnostic imaging , Male , Middle Aged , Tertiary Care Centers , Turkey , beta-Thalassemia/blood , beta-Thalassemia/complications
2.
Nefrología (Madr.) ; 35(1): 50-57, ene.-feb. 2015. ilus, tab
Article in Spanish | IBECS | ID: ibc-133197

ABSTRACT

Introducción: La hemodiafiltración on-line (HDF-OL) es actualmente la técnica más efectiva y varios estudios aleatorizados y metaanálisis han visto una reducción de la mortalidad, observándose una asociación en relación directa con el volumen convectivo. El flujo de sangre (Qb) limita el flujo de infusión al 25-33 % y constituye el principal factor limitante para alcanzar un volumen de sustitución óptimo. Con la reciente incorporación de monitores con sistema de autosustitución, el objetivo del estudio fue valorar el efecto de las variaciones del Qb sobre el volumen convectivo y la capacidad depurativa. Material y métodos: Se incluyeron 23 pacientes, 17 varones y 6 mujeres, con una edad media de 65,5 ± 10 años, tiempo de diálisis 292,2 ± 15 min, que se encontraban en programa de HDF-OL con monitor 5008 Cordiax con autosustitución. Cada paciente fue analizado en cinco sesiones en las que solo se varió el Qb (250, 300, 350, 400 y 450 ml/min). En cada sesión se determinaron el volumen de sustitución, el volumen convectivo total y los parámetros de diálisis. Se determinó la concentración de urea (60 Da), creatinina (113 Da), β2-microglobulina (11 800 Da), mioglobina (17 200 Da), prolactina (23 000 Da), α1-microglobulina (33 000 Da) y α1-glicoproteína ácida (40 000 Da) en plasma al inicio y al final de cada sesión para calcular el porcentaje de reducción de estos solutos. Resultados: La presión transmembrana fue inferior con Qb 250 ml/min. Se observó un aumento significativo del volumen convectivo con el incremento del Qb, 23,7, 26,9, 30,2, 32,8 y 35,2 l/sesión a 250, 300, 350, 400 y 450 ml/min, respectivamente (P < 0,001), representando un porcentaje de la sangre total depurada del 33,2, 31,2, 30,2, 28,7 y 27,3 %, respectivamente. Los porcentajes de reducción de urea y creatinina aumentaron progresivamente con el Qb, se observaron ligeras diferencias con la β2-microglobulina y la mioglobina, y no se observaron cambios en las grandes moléculas. Conclusión: Por cada 50 ml/min de aumento del Qb el volumen convectivo aumenta entre 8 y 12 ml/min. El sistema de autosustitución potencia los Qb más bajos en el porcentaje del volumen convectivo respecto a la sangre total depurada. El Qb aumenta la capacidad depurativa de las moléculas pequeñas, favorece la de la β2-microglobulina y la mioglobina, y no influye en moléculas de superior peso molecular (AU)


Introduction: On-line haemodiafiltration (OL-HDF) is currently the most effective technique and several randomised studies and meta-analyses have seen a reduction in mortality and an association directly related with convective volume is observed. Blood flow (Qb) limits the infusion rate to 25-33 % and is the main limiting factor for reaching an optimum substitution volume. With the recent incorporation of monitors with auto-substitution systems, the aim of the study was to assess the effect of Qb variations on convective volume and purifying capacity. Material and Methods: 23 patients, 17 men and 6 women, were included, with an average age of 65.5 ±10 years, time on dialysis 292.2 ± 15 minutes, which were in the OL-HDF programme with the 5008 Cordiax monitor with auto-substitution. Each patient was analysed over 5 sessions in which only the Qb was changed (250, 300, 350, 400 and 450 ml/min). In each session the substitution volume, total convective volume and parameters of dialysis were measured. The concentration of urea (60 Da), creatinine (113 Da), β2-microglobulin (11,800 Da), myoglobin (17,200 Da), prolactin (23,000 Da), α1-microglobulin (33,000 Da) and α1-acid glycoprotein (40,000 Da) in plasma was measured at the start and end of each session in order to calculate the percentage of reduction of these solutes. Results: The trans-membrane pressure was less, with Qb 250 ml/min. A significant increase in convective volume was observed with the increase in Qb, 23.7, 26.9, 30.2, 32.8 and 35.2 l/session to 250, 300, 350, 400 and 450 ml/min, respectively (P < 0.001), representing a percentage of total purified blood of 33.2, 31.2, 30.2, 28.7 and 27.3 % respectively. The percentages of reduction of urea and creatine progressively increased with Qb, slight differences were observed with β2-microglobulin and myoglobin, and no changes were observed in the larger molecules. Conclusion: For each 50 ml/min increase in Qb, the convective volume increased by between 8 and 12 ml/min. The auto-substitution system strengthens the lowest Qbs in the percentage of convective volume with regards to total purified blood. Qb increases the purifying capacity of small molecules, favouring that of β2-microglobulin and myoglobin, and does not influence molecules of a greater molecular weight (AU)


Subject(s)
Humans , Hemodiafiltration/methods , Metabolic Clearance Rate/physiology , Renal Blood Flow, Effective/physiology , Renal Dialysis/methods , 34774
4.
Curr Radiopharm ; 5(1): 65-70, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21864246

ABSTRACT

UNLABELLED: The ligand, carboxymethylthioethyl iminodiacetic acid (CMT-IDA) has a suitable array of donor atoms for coordination with [99mTc(CO)3]+ core, wherein the resultant complex is expected to possess free carboxylic residues contributing towards hydrophilicity of the complex. The aim of the studies was to study the renal clearance of 99mTc(CO)3- labeled CMT-IDA and determine the potential of the complex towards its use as a renal tubular imaging agent. METHODS: CMT-IDA was radiolabeled with the [99mTc(CO)3(H2O)3]+ precursor and was characterized by reverse phase HPLC gradient elution system. Stability, hydrophilicity and plasma protein binding studies were carried out for the complex. Biodistribution studies were carried out in normal male Swiss mice at 10 min.p.i. and 2 h.p.i. The clearance was estimated from the activity observed in the urinary bladder by tying the urethra prior to injection of the complexes under study. Imaging studies were performed with male Swiss mice administered with [99mTc(CO)3(CMT-IDA)]-2 at 30 min. p.i. and blocking studies were carried out by intraperitoneal injection of probenecid 10 min. prior to the injection of the radiotracer. RESULTS: [99mTc(CO)3(CMT-IDA)]-2 could be obtained in > 98% radiochemical purity. The complex showed renal clearance of 71.0� 5.9% ID at 10 min.p.i. which increased to 84.1� 10.6% ID at 2 h.p.i., with no major activity in blood, liver, heart, lungs, stomach and spleen. However, the intestinal uptake was high (10.3� 2.0% ID) at 2 h.p.i. Scintigraphic image of the animal injected with probenecid showed an increase in the activity in kidneys indicating excretion of the [99mTc(CO)3(CMT-IDA)]-2 complex via tubular pathway. CONCLUSION: The complex, [99mTc(CO)3(CMT-IDA)]-2 has shown excellent renal clearance and thereby can be explored further for potential use as an agent towards assessing effective renal plasma flow.


Subject(s)
Imino Acids/chemical synthesis , Kidney Tubules/metabolism , Organotechnetium Compounds/chemical synthesis , Radiopharmaceuticals/chemical synthesis , Animals , Chromatography, High Pressure Liquid , Imino Acids/pharmacokinetics , Kidney Tubules/diagnostic imaging , Kidney Tubules/physiology , Male , Mice , Organotechnetium Compounds/pharmacokinetics , Radionuclide Imaging , Radiopharmaceuticals/pharmacokinetics , Renal Blood Flow, Effective/physiology
5.
Nephrol Ther ; 8(2): 96-100, 2012 Apr.
Article in French | MEDLINE | ID: mdl-22019735

ABSTRACT

BACKGROUND: Access blood flow measurements are considered useful indicators for thrombosis prevention. It was the purpose of this study to compare measurements of access blood flow by two different techniques: duplex doppler and BTM thermodilution. METHODS: Patients included must be on chronic hemodialysis on arterioveinous vascular access. They must be in a unit fit with hemodialysis generator equipped with BTM tool. The measurements of access blood flow were made during the first hour of the hemodialysis session. A measurement with each technique was performed for each patient. RESULTS: Fifteen patients were included: seven men and eight women, average age 60.8 ± 9.2 years, average weight 76 ± 16 kg, duration on hemodialysis therapy 6.6 ± 6.1 years. Access blood flow was native fistula (14 patients) and a prothetic access (one patient). Average access blood flow was 1088 ± 586 mL/mn (doppler) and 1094 ± 570 mL/mn (BTM). Comparison of access flows obtained by the BTM and doppler techniques showed a strong linear relationship. The average time to perform a measure was six minutes for the doppler technique and five minutes for the BTM technique. No adverse effect was observed in our study. CONCLUSION: Our study shows a strong correlation between the two techniques (doppler and BTM) for the measurement of hemodialysis access blood flow. The BTM access blood flow measurement technique is fast, economic and made during the hemodialysis session by the nurse.


Subject(s)
Arteriovenous Shunt, Surgical/methods , Renal Blood Flow, Effective/physiology , Renal Dialysis/methods , Thermodilution/methods , Ultrasonography, Doppler, Duplex/methods , Vascular Access Devices/adverse effects , Aged , Female , Humans , Male , Middle Aged , Monitoring, Physiologic , Temperature , Thrombosis/prevention & control
8.
J Am Soc Nephrol ; 21(12): 2053-8, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20947631

ABSTRACT

There is ongoing controversy about the mechanisms that determine the characteristics of the glomerular filter. Here, we tested whether flow across the glomerular filter generates extracellular electrical potential differences, which could be an important determinant of glomerular filtration. In micropuncture experiments in Necturus maculosus, we measured a potential difference across the glomerular filtration barrier that was proportional to filtration pressure (-0.045 mV/10 cm H2O). The filtration-dependent potential was generated without temporal delay and was negative within Bowman's space. Perfusion with the cationic polymer protamine abolished the potential difference. We propose a mathematical model that considers the relative contributions of diffusion, convection, and electrophoretic effects on the total flux of albumin across the filter. According to this model, potential differences of -0.02 to -0.05 mV can induce electrophoretic effects that significantly influence the glomerular sieving coefficient of albumin. This model of glomerular filtration has the potential to provide a mechanistic theory, based on experimental data, about the filtration characteristics of the glomerular filtration barrier. It provides a unique approach to the microanatomy of the glomerulus, renal autoregulation, and the pathogenesis of proteinuria.


Subject(s)
Cell Membrane Permeability/physiology , Glomerular Basement Membrane/physiology , Kidney Glomerulus/physiology , Membrane Potentials/physiology , Animals , Biological Transport, Active , Disease Models, Animal , Electric Impedance , Glomerular Basement Membrane/metabolism , Glomerular Filtration Rate , Humans , Kidney Diseases/physiopathology , Kidney Glomerulus/blood supply , Necturus maculosus , Renal Blood Flow, Effective/physiology
9.
J Am Soc Nephrol ; 21(11): 1891-902, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20829403

ABSTRACT

Prenatal ethanol exposure is teratogenic, but the effects of ethanol on kidney development and the health of offspring are incompletely understood. Our objective was to investigate the effects of acute ethanol exposure during pregnancy on nephron endowment, mean arterial pressure, and renal function in offspring. We administered ethanol or saline by gavage to pregnant Sprague-Dawley rats on embryonic days 13.5 and 14.5. At 1 month of age, the nephron number was 15% lower and 10% lower in ethanol-exposed males and females, respectively, compared with controls. Mean arterial pressure, measured in conscious animals via indwelling tail-artery catheter, was 10% higher in both ethanol-exposed males and females compared with controls. GFR was 20% higher in ethanol-exposed males but 15% lower in ethanol-exposed females; moreover, males had increased proteinuria compared with controls. Furthermore, embryonic kidneys cultured in the presence of ethanol for 48 hours had 15% fewer ureteric branch points and tips than kidneys cultured in control media. Taken together, these data demonstrate that acute prenatal ethanol exposure reduces the number of nephrons, possibly as a result of inhibited ureteric branching morphogenesis, and that these changes affect adult cardiovascular and renal function.


Subject(s)
Animals, Newborn/physiology , Ethanol/adverse effects , Hypertension/physiopathology , Nephrons/pathology , Nephrons/physiopathology , Prenatal Exposure Delayed Effects/pathology , Prenatal Exposure Delayed Effects/physiopathology , Animals , Blood Pressure/drug effects , Blood Pressure/physiology , Body Weight/physiology , Disease Models, Animal , Ethanol/pharmacology , Female , Glomerular Filtration Rate/physiology , Heart Rate/physiology , Hypertension/pathology , Kidney/embryology , Kidney/pathology , Kidney/physiopathology , Male , Nephrons/embryology , Organ Size/physiology , Pregnancy , Rats , Rats, Sprague-Dawley , Renal Blood Flow, Effective/physiology
10.
Intensive Care Med ; 36(3): 533-40, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20049587

ABSTRACT

OBJECTIVE: To investigate the short- and medium-term renal hemodynamic and functional responses to both short and sustained hypoperfusion. SUBJECTS: Eleven Merinos ewes. SETTING: Animal laboratory of the University Physiology Institute. DESIGN: Prospective observational study. INTERVENTIONS: Studies were performed in conscious sheep after unilateral nephrectomy with a vascular occluder and flow probe implanted on the remaining renal artery. In five sheep, renal blood flow (RBF) was reduced by 25, 50 and 75%, respectively, by acute vascular occlusion for 30 min at weekly intervals. In another six sheep, RBF was reduced by 80% for 2 h. MEASUREMENTS AND RESULTS: After 25, 50 or 75% renal hypoperfusion for 30 min, there was no associated extended loss of renal function. During 2 h of 80% hypoperfusion, urine output decreased from 80 to 17 ml, and creatinine clearance from 32 to 3 ml/min, whereas plasma creatinine increased from 103 to 132 mumol/l, and fractional excretion of sodium and urea increased. Release of occlusion induced brief hyperemia before all measured variables returned to normal within 8 h and remained normal for the following 72 h. At autopsy, the kidneys were histopathologically normal. CONCLUSIONS: Various degrees of renal hypoperfusion for 30 min did not induce prolonged changes in renal function or blood flow. Even with sustained severe hypoperfusion, there was rapid recovery to baseline function and flow. Unlike total ischemia, severe hypoperfusion alone is insufficient to induce subsequent persistent AKI.


Subject(s)
Hemodynamics/physiology , Ischemia/physiopathology , Kidney Function Tests , Renal Blood Flow, Effective/physiology , Acute Kidney Injury/blood , Acute Kidney Injury/etiology , Acute Kidney Injury/urine , Animals , Glomerular Filtration Rate/physiology , Kidney Cortex Necrosis , Kidney Function Tests/methods , Prospective Studies , Sheep , Victoria
11.
BJU Int ; 105(1): 125-8, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19493265

ABSTRACT

OBJECTIVE: To present our findings of simultaneous bilateral percutaneous nephrolithotomy (sbPCNL) on bilateral renal haemodynamic and excretory function in an in vivo pig model, as despite sbPCNL being a treatment strategy for patients with bilateral renal stones, the functional response of both kidneys to such a procedure is unknown. MATERIALS AND METHODS: Nine anaesthetized female pigs ( approximately 70 kg) had a single-tract PCNL procedure in the left kidney and then the right kidney in one session (sbPCNL). Percutaneous access was achieved by a 30 F balloon dilator system. Bilateral renal function was measured before, 1.5 and 4.5 h after sbPCNL and included glomerular filtration rate (GFR), effective renal plasma flow (RPF), renal extraction of para-aminohippurate (EPAH, a measure of the efficiency of tubular organic anion transport), urine flow (UV), absolute sodium excretion (UNaV) and fractional sodium excretion (FENa). RESULTS: Both kidneys had similar baseline haemodynamic and excretory function, and showed comparable changes after sbPCNL. Bilateral GFR and RPF decreased by approximately 35% at 1.5 and 4.5 h after sbPCNL; EPAH was reduced to a similar degree in both kidneys at 1.5 h after sbPCNL and remained depressed throughout the observation period; bilateral UV and UNaV progressively decreased by approximately 30% and approximately 60% at 1.5 and 4.5 h after sbPCNL, respectively; bilateral FENa did not significantly change at 1.5 h after sbPCNL but decreased significantly by approximately 50% at 4.5 h. CONCLUSIONS: Both kidneys responded in a similar fashion after sbPCNL, with declines in haemodynamic and excretory function. These bilateral functional responses were comparable to those previously reported after unilateral PCNL, and help to reduce concerns that PCNL of both kidneys in one session could lead to greater functional complications, at least acutely.


Subject(s)
Kidney/physiopathology , Nephrostomy, Percutaneous/methods , Animals , Blood Pressure/physiology , Female , Glomerular Filtration Rate/physiology , Kidney Function Tests , Nephrostomy, Percutaneous/adverse effects , Renal Blood Flow, Effective/physiology , Sodium/urine , Swine , p-Aminohippuric Acid/urine
12.
J Med Assoc Thai ; 89(9): 1479-86, 2006 Sep.
Article in English | MEDLINE | ID: mdl-17100388

ABSTRACT

OBJECTIVE: The objective of this study was to determine if a correlation exists between the effective renal plasma flow (ERPF) and the extraction fraction (EF) using 99mTc MAG3 in children. This EF has been previously described with 9mTc DTPA. However, the renal imaging agent of choice has become 9mTc MAG3. MATERIAL AND METHOD: The study was approved by The Children's Hospital of Philadelphia's institutional review board. Informed consent was also obtained A retrospective study of 29 children (16 males, 13 females) of ages 1 month to 19.5 years who underwent 99mTc MAG3 renal scintigraphy from September 2001 to December 2001 was analysed. EF values were calculated with and without attenuation correction in each kidney by determining the counts in a region of interest, correcting for background and comparing the counts with the injected dose. The EF was compared to the ERPF calculated using the Schlegel's method. The correlation between the EF and the ERPF corrected and non-corrected for soft tissue attenuation, were determined and were identified by using linear regression analysis. RESULTS: There was significant correlation between the ERPF and the EF with (r = 0.62, p < 0.05 on the left, r = 0.51, p = 0.005 on the right) than without attenuation correction (r = 0.54, p = 0.003 on the left, r = 0.42, p = 0.022 on the right). CONCLUSION: These results indicate a correlation of the ERPF calculated using the Schlegel's method with EF obtained from a 99mTc MAG3 renal scintigraphy. The EF may be the good alternative parameter for calculation of renal function, potentially more practical in pediatric patient and the ERPF for 99mTc MAG3 using the established software program based on Schlegel's formula.


Subject(s)
Kidney Diseases/physiopathology , Radiopharmaceuticals , Renal Blood Flow, Effective/physiology , Technetium Tc 99m Mertiatide , Adolescent , Adult , Child , Child, Preschool , Data Interpretation, Statistical , Female , Humans , Infant , Kidney Diseases/diagnostic imaging , Male , Radionuclide Imaging , Radiopharmaceuticals/blood , Renal Dialysis , Technetium Tc 99m Mertiatide/blood
14.
Am J Kidney Dis ; 40(6): 1277-82, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12460047

ABSTRACT

BACKGROUND: The aim of this study is to assess the evolution of intra-access flow (Q(ac)) in recently created native arteriovenous fistulae (AVFs) during the first few months of use. METHODS: All AVFs were monitored by means of ultrasound dilution using Transonic (Transonic Systems Inc, Ithaca, NY). First Q(ac) measurements were obtained between 6 to 10 weeks after creation and subsequently every 3 to 6 weeks during the following 4 months. Per routine, AVFs are cannulated 6 weeks after their creation in our unit. Fifty-seven patients with new AVFs were initially enrolled, but 12 patients were lost at follow-up. There was a 69% to 31% ratio of brachiocephalic (BC) to radiocephalic (RC) AVFs, and diabetes affected an equal proportion of patients in both subtypes. RESULTS: Mean initial and final Q(ac)s were 1,132 +/- 681 and 1,097 +/- 644 mL/min, respectively; there was no significant difference during the study period. However, the Q(ac) of BC AVFs remained approximately twice as high as the Q(ac) of RC AVFs during the observation period (initial Q(ac), 1,336 +/- 689 versus 645 +/- 332 mL/min; final Q(ac), 1,285 +/- 652 versus 647 +/- 331 mL/min, respectively). Male sex was associated with a greater Q(ac) throughout the evaluation (1,263 +/- 754 versus 852 +/- 375 mL/min for women). No significant difference was noted between different age groups, and diabetes did not significantly affect Q(ac). Finally, the initial Q(ac) of a BC AVF was influenced by the presence of a previously functioning RC AVF on the same arm. The initial Q(ac) in BC AVFs was 1,800 +/- 919 mL/min in that subgroup (and decreased to 1,302 +/- 733 mL/min by the end of the study, therefore becoming similar to the mean Q(ac) of other BC AVFs). CONCLUSION: From these results, we conclude that newly created native AVFs have an initial Q(ac) that does not vary significantly during the first 6 months and may already be maximal at 6 weeks or at the time of first needle puncture in our hands. Among demographic factors, sex influences the Q(ac) of native AVFs, whereas age and diabetes do not.


Subject(s)
Arteriovenous Shunt, Surgical/methods , Catheters, Indwelling , Aged , Diabetes Mellitus/therapy , Female , Follow-Up Studies , Graft Occlusion, Vascular/diagnostic imaging , Humans , Male , Middle Aged , Prospective Studies , Renal Blood Flow, Effective/physiology , Renal Dialysis/methods , Time Factors , Ultrasonics , Ultrasonography
15.
Vet Radiol Ultrasound ; 41(1): 85-8, 2000.
Article in English | MEDLINE | ID: mdl-10695886

ABSTRACT

Ten healthy horses were injected intravenously with 99mTc-MAG3 and the disappearance of radioactivity from the blood was measured. The total body clearance (Cl(B)) and elimination half-life (t1/2(beta)) were 7.9 +/- 1.5 ml/kg/minute and 32.8 +/- 4.1 minutes, respectively. The disappearance of 99mTc-MAG3 from the blood of 2 horses with compromised renal function was also measured. The data suggest that 99mTc-MAG3 is a useful and clinically applicable radiopharmaceutical for measurement of effective renal blood flow in the horse.


Subject(s)
Horses/physiology , Kidney/diagnostic imaging , Radiopharmaceuticals , Technetium Tc 99m Mertiatide , Animals , Colitis/microbiology , Colitis/veterinary , Female , Follow-Up Studies , Half-Life , Horse Diseases/diagnostic imaging , Hydronephrosis/veterinary , Injections, Intravenous , Kidney/physiology , Kidney Calculi/veterinary , Male , Metabolic Clearance Rate , Radionuclide Imaging , Radiopharmaceuticals/administration & dosage , Radiopharmaceuticals/blood , Renal Blood Flow, Effective/physiology , Renal Insufficiency/diagnostic imaging , Renal Insufficiency/veterinary , Rhabdomyolysis/veterinary , Salmonella Infections, Animal/complications , Technetium Tc 99m Mertiatide/administration & dosage , Technetium Tc 99m Mertiatide/blood
16.
Urol Nefrol (Mosk) ; (1): 11-4, 1998.
Article in Russian | MEDLINE | ID: mdl-9532937

ABSTRACT

The paper presents experimental evidence on morphologic changes in intact kidney, tissue temperature, renal blood supply and glomerular filtration in response to freezing. Cryogenic effects manifested as necrotic and dystrophic processes. Damage to the tubular and glomerular cells can be corrected. Blood flow in the kidney was not interrupted but was directed through the bypass routes.


Subject(s)
Freezing , Kidney/pathology , Kidney/physiopathology , Renal Blood Flow, Effective/physiology , Animals , Body Temperature , Cats , Dogs , Glomerular Filtration Rate , Kidney/blood supply , Necrosis
18.
Rev. sanid. mil ; 49(5): 106-8, sept.-oct. 1995.
Article in Spanish | LILACS | ID: lil-173839

ABSTRACT

A 25 pacientes adultos, en buenas condiciones generales se les practicó cirugía de la columna vertebral o histerectomía abdominal bajo anestesia general balanceada. Se constató disminución franca de la diuresis transoperatoria a pesar de la adecuada estabilidad cardiocirculatoria y persfusión de líquidos parenterales. Posiblemente el procedimiento anestésico quirúrgico, la posición prona y la comprensión intra-abdominal determinaron cambios en los mecanismos intrínsecos y extrínsicos que controlan el flujo sanguíneo renal y la velocidad de filtración glomerular siendo indispensable la vigilancia continua de la diuresis horaria y procurar protección renal en el periodo trans-anestésico


Subject(s)
Humans , Spine/surgery , Surgical Procedures, Operative , Urine/physiology , Diuresis/physiology , Hysterectomy , Renal Blood Flow, Effective/physiology , Kidney/physiology
19.
Microvasc Res ; 49(1): 1-11, 1995 Jan.
Article in English | MEDLINE | ID: mdl-7746158

ABSTRACT

Poiseuille's formula is conventionally used to calculate hydraulic resistance of blood capillaries. This law, however, applies to tubes with constant diameter and straight axis. Since blood capillaries, especially in the glomerular microcirculation, are far from having these features, we wanted to estimate the effect of the shape of glomerular capillary segments on the calculation of their hydraulic resistance in comparison to the values obtained with Poiseuille's formula. We studied blood flow through capillary segments of a reconstructed glomerular network from a normal Munich-Wistar rat. Geometrical parameters of capillary segments derived from serial section reconstruction of the glomerulus were used to perform numerical analysis of blood flow. Non-Newtonian properties of blood were simulated by calculating apparent blood viscosity as a function of local rheological parameters for each capillary segment. The numerically calculated hydraulic resistances were always higher than those given by the Poiseuille equation (from 22 to 99%), and this was attributed to the geometrical complexity of the reconstructed vessels. We also performed simulations of the blood flow and filtration along the glomerular network using a previously developed theoretical model that considers the topographical organization of the network structure and dimensions of individual capillary segments. Considering higher hydraulic resistances (as estimated with the numerical analysis) we found that the calculated ultrafiltration coefficient did not change appreciably, but the total network pressure drop and the fraction of filtering surface area at filtration equilibrium were higher than previously estimated.


Subject(s)
Capillary Resistance/physiology , Kidney Glomerulus/blood supply , Numerical Analysis, Computer-Assisted , Renal Blood Flow, Effective/physiology , Animals , Blood Flow Velocity/physiology , Kidney Glomerulus/cytology , Kidney Glomerulus/physiology , Microcirculation/physiology , Models, Cardiovascular , Rats , Rats, Wistar
20.
Clin Transplant ; 8(3 Pt 2): 319-23, 1994 Jun.
Article in English | MEDLINE | ID: mdl-8061373

ABSTRACT

Chronic allograft rejection very probably results from the interactions between allogeneic immune injury, tissue reactions in response to injury, and local intragraft hemodynamic adaptations to the progressive loss of functioning organ mass. We examined each of these components in a rat model of chronic renal allograft rejection. Although immunofluorescence studies of renal allografts with chronic rejection usually reveal nondiagnostic patterns of immunoglobulin deposits, we found, using Western blot analysis, donor-directed antibodies against novel glomerular basement membrane antigens in the sera of animals with chronic rejection-associated transplant glomerulopathy. Stop-flow micropuncture studies have shown that the glomerular capillary pressure in transplanted kidneys resembles that of the donor strain kidney in response to renal ablation. Northern blots for growth factor transcripts showed induced expression of mRNA levels for various growth factors in long-surviving renal transplants. Reduction in intraglomerular pressure was associated with increased recipient survival, preservation of renal function, decreased amounts of proteinuria, and less severe structural lesions in the glomeruli. We conclude that the glomerular lesions of chronic rejection may arise from a combination of antiglomerular (allo) antibodies in conjunction with increased intraglomerular pressures and local production of growth factors. The vascular lesions and interstitial scarring of chronic rejection may arise from previous episodes of graft vasculitis and interstitial inflammation, respectively.


Subject(s)
Graft Rejection/immunology , Graft Rejection/pathology , Kidney Transplantation/immunology , Kidney Transplantation/pathology , Animals , Antibodies/analysis , Antibodies/immunology , Basement Membrane/immunology , Basement Membrane/pathology , Chronic Disease , Growth Substances/analysis , Growth Substances/physiology , Kidney Glomerulus/immunology , Kidney Glomerulus/pathology , Rats , Rats, Inbred F344 , Rats, Inbred Lew , Renal Blood Flow, Effective/physiology
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