Percutaneous catheterization of the internal jugular vein for hemodialysis

OBJECTIVES

The present study was aimed at evaluating the clinical experiences in the internal jugular venous catheterization for hemodialysis.

METHODS

We retrospectively analyzed the data on internal jugular venous catheterization at Chonnam National University Hospital from May 2000 to February 2001.

RESULTS

There were 132 uremic patients with a total of 150 attempts of internal jugular cannulation. Overall success rate was 90.9% with average puncture trials of 2.3 +/- 2.1. 124 (82.7%) of the catheterization attempts were made on the right side and 26 (17.3%) were made on the left. The catheters were left in place from 2 to 87 days with an average of 19.5 +/- 15.3 days per catheter. The dialysis sessions per catheter were from 2 to 58 with an average of 11.3 +/- 6.8. The mean blood flow during hemodialysis immediately after catheterization was 213.4 +/- 42.2 ml/min. Thirty two (21.3%) patients had early complications. These included carotid artery puncture (11.3%), local bleeding (4.7%), local pain (3.3%), neck hematoma (0.7%) and malposition of the catheter (1.3%). Seventeen (11.3%) patients had late complications. These included fever or infection (11.3%), inadequate blood flow rate (3.3%) and inadvertent withdrawal (2.0%). There was no catheter-related mortality.

CONCLUSIONS

Our experiences revealed that the internal jugular vein catheterization is relatively safe and efficient for temporary vascular access for hemodialysis.

Amphotericin B decreases adenylyl cyclase activity and aquaporin-2 expression in rat kidney

The present study was intended to examine whether the amphotericin-induced urinary concentration defect can be related to an altered regulation of aquaporin (AQP) water channels in the kidney. Male Sprague-Dawley rats were injected with amphotericin B (6 mg/kg/d, IP ) for 21 days. The protein expression of AQP1-3, Gsalpha, and adenylyl cyclase was determined in the kidney. To further specify the primary point of dysregulation of AQP channels that are activated by the arginine vasopressin/cyclic adenosine monophosphate (AVP/cAMP) pathway, different components of adenylyl cyclase complex were separately examined for their cAMP-generating activities. Amphotericin treatment resulted in kidney failure associated with decreased tubular water reabsorption and increased urinary flow rate. The expression of AQP2 proteins was significantly decreased in the outer medulla and inner medulla but not in the cortex. The expression of AQP2 proteins in the membrane fraction changed in parallel with that in the cytoplasmic fraction, suggesting a preserved targeting. Neither the expression of AQP1 nor that of AQP3 was significantly affected in the cortex, outer medulla, or inner medulla. The cAMP generation in response to AVP or sodium fluoride was decreased, whereas that to forskolin was not significantly altered. The expression of Gsalpha proteins was decreased in the inner medulla, whereas that of adenylyl cyclase VI remained unaltered. These findings indicate that the amphotericin-induced urinary concentration defect may in part be causally related to a reduced abundance of AQP2 channels in the kidney. It is also suggested that the primary impairment in the pathway leading to the activation of AQP channels that are regulated by the AVP/cAMP pathway lies at the level of G proteins.

The predictive parameters of erythropoietin hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis

BACKGROUND

The present study was aimed at investigating the predictive parameters of erythropoietin (epoetin) hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis (CAPD).

METHODS

We studied 40 patients with end-stage renal disease who had been receiving CAPD for at least 6 months and epoetin therapy for at least more than 2 months. Pearson's simple correlation and multiple stepwise linear regression analysis was used to discover what parameter can predict epoetin resistance. We expressed epoetin resistance index (ERI) as weekly epoetin dose/hematocrit/body weight'. The dose of epoetin is titrated by about 25% every 2 to 4 weeks to maintain a target hematocrit level between 33% and 36%.

RESULTS

We analyzed the relationship between ERI and other predictive parameters by Pearson's correlation. These results showed ERI has a statistically significant correlation with transferrin saturation (TS) (r = -0.327, p = 0.042), total weekly Kt/Vurea (r = -0.423, p = 0.018), serum albumin level (r = -0.458, p = 0.003), normalized protein catabolic rate (nPCR) (r = -0.479, p = 0.006), normalized protein equivalent of total nitrogen appearance (nPNA) (r = -0.488, p = 0.005) and serum C-reactive protein (CRP) (r = 0.332, p = 0.036). Regression analysis was performed using stepwise linear regression for multiple variables to discover the most independent variable which is correlated with ERI. ERI was entered as a dependent variable, whereas the other parameters (age, duration of peritoneal dialysis, serum albumin level, CRP, serum ferritin, total weekly Kt/Vurea, nPCR, nPNA, serum iPTH, serum aluminium, TS) were entered as independent variables. This analysis showed CRP is the most significant variable and, if CRP is excluded, nPNA is the significant variable. CRP has a statistically significant correlation with serum albumin level (r = -0.418, p = 0.007) and total weekly Kt/Vurea (r = -0.366, p = 0.043). High CRP group has more increased level of ERI (p < 0.05), age (p < 0.05) and serum creatinine level (p < 0.05) than normal control, but more decreased level of serum albumin (p < 0.01) and serum iron levels (p < 0.05).

CONCLUSION

These results indicate that CRP is the most important predictor of epoetin hyporesponsiveness.

Pelvic aspergillosis with tubo-ovarian abscess in a renal transplant recipient

Common clinical manifestations of aspergillosis in renal transplant recipients are fever and pulmonary infiltrates, but involvement of the reproductive system is rare. We report a case of pelvic aspergillosis with tubo-ovarian abscess in a renal transplant patient. The patient received a cadaveric renal transplantation, and two episodes of acute rejection were treated with methylprednisolone pulse therapy. Surgical biopsy specimens of pelvic abscess detected by ultrasonogram and CT revealed Aspergillus. With amphotericin B treatment, the patient is well with normalization of erythrocyte sedimentation rate and C-reactive protein.

ATP-sensitive K+ current and its modulation by substance P in gastric myocytes isolated from guinea pig

To investigate whether ATP-sensitive K+ channels exist in gastric smooth muscle of the guinea pig and whether they are modulated by substance P, we recorded lemakalim-activated K+ currents from freshly isolated cells using the standard whole-cell configuration. With 0.1 mM ATP and 140 mM K+ in the pipette and 90 mM K+ in the bath solution and a holding potential of -80 mV, lemakalim (10 microM) activated a glibenclamide-sensitive inward current with a mean amplitude of -224+/-34 pA. These currents were voltage-independent from -90 to 0 mV and K+-selective. Increasing the intracellular ATP concentrations from 0.1 to 3 mM reduced the lemakalim-activated currents by about five-fold. External barium and cesium inhibited the lemakalim-activated currents in a dose-dependent manner. External tetraethylammonium (10 mM) inhibited the lemakalim-activated currents by 66+/-15%. Bath application of substance P (5 microM) inhibited the lemakalim-activated currents by 53+/-13% and this inhibition was absent when 0.5 mM guanosine 5'-O-(2-thiodiphosphate) (GDPbetaS) was in the pipette. Phorbol 12,13-dibutyrate (PDB) inhibited the lemakalim-activated currents by 71+/-3%. Chelerythrine (1 microM) reduced the substance P-induced inhibition of lemakalim-activated currents by 22.2+/-11.3%. These results suggest the presence of ATP-sensitive K+ channels in gastric smooth muscle and that substance P inhibits ATP-sensitive K+ channels via G-protein through protein kinase C activation.

Serotonin stimulates protein tyrosyl phosphorylation and vascular contraction via tyrosine kinase

Serotonin (5-HT, 5-hydroxytryptamine) is a mitogen in vascular smooth muscle and vascular reactivity to 5-HT is significantly enhanced in hypertension and atherosclerosis. We have tested the hypothesis that tyrosine kinases, enzymes important for mitogenesis, may play a role in 5-HT-induced vascular smooth muscle contractility. Helical strips of rat carotid artery and aorta denuded of endothelium were mounted in tissue baths for measurement of contractile force. The tyrosine kinase inhibitor genistein (5 x 10(-6) M) decreased the potency of 5-HT approximately 4-fold and reduced maximal contraction to 5-HT in carotid arterial strips denuded of endothelium (58% control). Genistein's inactive congener daidzein (5 x 10(-6) M) did not reduce maximal contraction to 5-HT in carotid arteries but did shift the 5-HT concentration response curve 3-fold to the right. Tyrphostin 23 (5 x 10(-5) M), another tyrosine kinase inhibitor, decreased the potency of 5-HT 4-fold and reduced the maximal contraction to 5-HT in the carotid artery (10% control). Contractions induced by phorbol-12,13-dibutyrate (10(-9) to 10(-5) M) were not reduced or shifted by either tyrosine kinase inhibitor, indicating that phorbolester-sensitive protein kinase C isoforms were not affected. KCl-induced contraction was shifted 2-fold and the maximum significantly inhibited by tyrphostin 23 (38.6% control) but not genistein or daidzein, indicating that tyrphostin 23 but not genistein may inhibit voltage-gated calcium channels to reduce contractility. Western blot analysis using antiphosphotyrosine antibody confirmed that 5-HT produced a time- and concentration-dependent increase in the phosphotyrosine immunoreactivity of a 42-kD protein in cultured aortic smooth muscle cells. Lysate immunoprecipitation with an antimitogen-activated-protein (MAP)-kinase antibody indicated that the 42-kD protein was most likely a MAP kinase. 5-HT (10(-5) M) stimulated contraction and increased antiphosphotyrosine immunoreactivity in whole aorta mounted in tissue baths. Importantly, aortic contraction to 5-HT was shifted (5-fold rightward) and reduced (69% control) by genistein but not daidzein. These findings demonstrate that (1) tyrosine kinase activation may partially mediate contractility to 5-HT in arterial smooth muscle, (2) tyrphostin 23 is somewhat nonselective and (3) 5-HT stimulates tyrosine kinase as documented by increased tyrosyl phosphorylation of proteins in cultured aortic smooth muscle cells and aortic tissue in active contraction of 5-HT. These findings have significant implications not only in understanding a novel pathway of 5-HT signal transduction but also in vascular diseases in which growth and/or contractility to 5-HT is increased (e.g. hypertension, atherosclerosis).

A case of adult-onset Bartter's syndrome

Bartter's Syndrome is characterized by renal potassium wasting with hypokalemia, metabolic alkalosis, increased renin-angiotensin-aldosterone system, normal blood pressure, resistance to the pressor effects of angiotensin II and juxtaglomerular cell hyperplasia. Most of the cases have been noted in the pediatric age group and adult-onset cases are very rare. We report a case of adult-onset Bartter's syndrome.