bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Bisphenol A in Effluents of Hemodialyzers
Authors: Yamasaki Hiroko , Nagake Yoshio , Makino Hirofumi
Published: April 2003

This study was designed to determine whether bisphenol A (BPA) is eluted from hemodialyzers in which polycarbonate and polysulfone based on BPA are used as materials. Four types of polysulfone hemodialyzer (PS hemodialyzer: PS-A, PS-B, PS-C and PS-D) and an ethylene-vinyl alcohol copolymer dialyzer (EVAL hemodialyzer) were used in this study. In the PS-C, PS-D and EVAL hemodialyzers, polycarbonate was used in the case headers at both ends of the hemodialyzer. In in vitro experiments, the hemodialyzers were filled with reverse osmotic water, and BPA concentrations were measured. Saline solution (200 ml) was then circulated through a blood circuit tube connected to the hemodialyzer, and BPA concentrations in the saline solution were measured. In in vivo experiments, BPA concentrations in whole blood samples from hemodialysis patients treated with PS-C (n = 3) and PS-D (n = 3) hemodialyzers were measured. In in vitro experiments, BPA was detected in the effluents of the PS-C, PS-D and EVAL hemodialyzers. In in vivo experiments, BPA was detected in whole blood samples from hemodialysis patients treated with the PS-D hemodialyzer (mean value, 0.77 ppb). This is the first report of BPA elution from hemodialyzers in which polycarbonate and polysulfone are used, and also the first report of detection of BPA in whole blood samples from patients on hemodialysis.
High Incidence of Severe Twin Hemodialysis Catheter Infections in Elderly Women
Authors: Tovbin D. , Mashal A. , Friger M. , Landver R. , Jan T. , Markowitz A. , Mostoslavsky M. , Gidron Y.
Published: April 2003

Background: Cuffed-tunneled hemodialysis (HD) catheters are recommended as a bridging therapy until peripheral access is available, but their long-term use is controversial. Aim: To evaluate the complications and lifetime of twin-tunneled HD catheters and to identify parameters which could predict their outcome. Methods: 29 chronic HD patients (19 female and 10 male) were inserted with twin hemodialysis catheters (28 Tesio, 1 Schon Duoflow), followed for up to 9 months or until catheter loss, and evaluated for severe catheter-related complications necessitating catheter removal. Since the most common severe complication was catheter-related infection, we retrospectively examined whether parameters such as age, gender, duration of end-stage renal disease, delivered dose of dialysis, nutrition, diabetes and indices of social support correlate with this outcome. Results: Severe catheter infection requiring catheter removal occurred in 11 patients (10 female). Of these infected female patients, 9 were elderly (≧67 years) and in 6 of those, catheter infection was fatal (54% of infected cases). At 9 months, severe catheter infection and related patient death rates were 38 and 21%, respectively. Severe catheter infection was significantly related to less social support (p < 0.005), older age, female gender, lower nPCR (all p < 0.05), and tended to be related to shorter end-stage renal disease duration prior to catheter insertion (p = 0.06). Conclusion: This study demonstrated that twin HD catheters are associated with a high incidence of severe catheter-related infections which was most significantly related to social-support as well as inadequate nutrition, older age and female gender. Therefore, we suggest early removal of the catheter, enhancement of social support and dietary counseling for the elderly and lonely HD patients using this type of catheter.
The Molecular Basis of Dutch Infantile Nephropathic Cystinosis
Authors: Heil Sandra G. , Levtchenko Elena , Monnens Leo A.H. , Trijbels Frans J.M. , van der Put Nathalie M.J. , Blom Henk J.
Published: April 2003

Infantile nephropathic cystinosis, an inborn error of metabolism with an autosomal recessive inheritance pattern, is characterized by lysosomal storage of the amino acid cystine due to an impaired transport of cystine out of the lysosomes. Initial clinical features consist of the renal Fanconi syndrome and crystals in the cornea. Oral therapy with cysteamine lowers the intracellular cystine content. Recently, the gene coding for the integral membrane protein cystinosin, which is responsible for membrane transport of cystine (CTNS), was cloned. Mutation analysis of the CTNS gene of Caucasian patients revealed a common 57-kb deletion, and several other mutations spread throughout the entire gene. In the present study, we developed an improved screening method for the detection of the common 57-kb deletion. By use of this method we detected the 57-kb deletion in 59% of the examined Dutch alleles. The remaining alleles were screened for other mutations by genomic sequencing of the different exons, revealing three previously described mutations. Furthermore, we studied a possible genotype-phenotype relation of the homozygous deleted patients, which could not be demonstrated in our study population. Next to biochemical determination of cystine in leukocytes or fibroblasts, molecular genetic analysis enables prenatal diagnosis and facilitates identification of carriers.
Trans-Tubular Potassium Gradient in Patients with Drug-Induced Hyperkalemia
Authors: Mayan Haim , Kantor Rami , Farfel Zvi
Published: April 2003

Background: Trans-tubular potassium gradient (TTKG) is considered to reflect mainly aldosterone bioactivity with regard to its kaliuretic response. We determined both TTKG and aldosterone serum concentrations in patients with severe drug-induced hyperkalemia (DIH). Methods: Ten hyperkalemic patients with serum potassium of more than 5.5 mEq/l, and serum creatinine of less than 2.5 mg/dl (221 µmol/l) were studied prospectively. Two control groups of 10 patients each were used. Control 1 group with normal renal function, and control 2 group with normokalemia and renal failure of the same magnitude as that of the hyperkalemic patients. Serum osmolarity, electrolytes, creatinine, aldosterone and urine electrolytes and osmolarity were measured and TTKG calculated. Results: DIH patients had lower TTKG values than control 1 patients (2.58 ± 0.36 vs. 6.68 ± 0.55, p < 0.001), and also lower than that of the control 2 patients (2.58 ± 0.36 vs. 5.51 ± 0.87, p < 0.01). Serum aldosterone concentration in the DIH group was higher than that of the control 1 group [24.30 ± 5.0 vs. 7.4 ± 2.1 pg/ml (674 ± 139 vs. 205 ± 58 pmol/l), p < 0.006] but not different from that of the control 2 group [24.3 ± 5.0 vs. 15.3 ± 3.8 pg/ml (674 ± 139 vs. 424 ± 106 pmol/l), respectively, p = 0.18]. Although there was some overlap in TTKG between DIH and control groups, 6 of 10 DIH patients had TTKG of less than 2.5, while none of the control patients had such a low value. Conclusion: DIH is characterized by lower TTKG values than those observed in patients with normal or mild-to-moderate renal failure. Other factors in addition to aldosterone seem to be involved.
Folate Supplementation in Peritoneal Dialysis Patients with Normal Erythrocyte Folate: Effect on Plasma Homocysteine
Authors: De Vecchi Amedeo F. , Patrosso Cristina , Novembrino Cristina , Finazzi Silvia , Colucci Patrizia , De Franceschi Michela , Fasano Maria Antonietta , Bamonti-Catena Fabrizia
Published: April 2003

The possible role of folate supplementation in reducing hyperhomocysteinemia in dialysis patients has been reported in several recent papers. However, scant data are available for peritoneal dialysis patients; besides, none of these studies investigated either the role of intraerythrocyte folate concentration or the presence of side effects caused by folate administration. Sixty-six peritoneal dialysis patients with hyperhomocysteinemia (>15 µmol/l) and normal folate status (as assessed by erythrocyte folate level >600 nmol/l) were randomly allocated to receive either oral folate (5 mg/day) or no vitamin supplementation. After 2 months of therapy, patients were requested to answer a questionnaire investigating the occurrence of symptoms possibly related to folate supplementation. Twenty-nine treated patients and 30 untreated controls completed the study. In the treated patients, serum and erythrocyte folate increased significantly (p < 0.0001) (respectively from 10.6 ± 4.9 to 237 ± 231 nmol/l and from 1,201 ± 297 to 2,881 ± 294 nmol/l) to levels at the uppermost limit of detection by laboratory methods. Serum vitamin B12 levels did not change. Plasma homocysteine levels decreased from 54 ± 32 to 23 ± 14 µmol/l after folate supplementation and remained unchanged in the control group. After 4 months of folate therapy, homocysteine concentration was within the normal range in 5 patients (17%) and below 30 µmol/l in the other 21 (72%). Folate therapy resulted in a decrease in homocysteine of more than 50% in 45% of the patients and decrease of more than 20% in a further 38%. No significant symptoms were reported. Thus, serum and erythrocyte folate increase confirms that normal folate levels are inadequate in dialysis patients, even if serum and erythrocyte levels before folate supplementation cannot predict the effect on homocysteine plasma levels.
Erythropoietin and Cardiocirculatory Condition in Aged Patients with Chronic Rena l Failure
Authors: Bedani P.L. , Verzola A. , Bergami M. , Stabellini G. , Gilli P.
Published: April 2003

Background/Aim: The clearest benefit of recombinant human erythropoietin (rHuEPO) in end-stage renal disease is a substantial reduction in transfusion dependency and an improved quality of life. In this report, we describe the efficacy of weekly subcutaneous administration of rHuEPO in 11 elderly patients with anemia secondary to chronic renal failure. Methods: The role of rHuEPO therapy in increasing the patient’s quality of life and in decreasing the hospitalization rates secondary to cardiac morbidity was verified in 11 elderly patients (age range between 66 and 85 years) with anemia due to chronic renal failure. The mean hemoglobin level at the beginning of the study was 8.2 ± (SD) 0.7 g/dl, and the serum creatinine concentration was 4.8 ± 1.36 mg/dl. The patients underwent baseline and annual echocardiography, in addition to an electrocardiogram. Results: Most patients experienced a partial regression of left ventricular hypertrophy, and no congestive heart failure was documented. The mean hemoglobin level during rHuEPO therapy increased to 11.3 ± 1.2 g/dl, while the mean serum creatinine concentration did not change significantly. Conclusions: Our results confirm that early anemia correction in aged chronic renal failure patients permits improvement of the quality of life, of exercise performance, and of cognitive functions. Reduced transfusion need and regression of left ventricular hypertrophy favor a minor incidence of cardiac morbidity and contribute to reduce health costs.
Hospitalizations for Fungal Infections after Initiation of Chronic Dialysis in the United States
Authors: Abbott Kevin C. , Hypolite Iman , Tveit Daniel P. , Hshieh Paul , Cruess David , Agodoa Lawrence Y.
Published: April 2003

Aims: Hospitalized fungal infections are reported frequently in renal transplant recipients and peritoneal dialysis patients, but the frequency of hospitalized fungal infections in dialysis patients has not been studied in a national population. Methods: 327,993 dialysis patients in the United States Renal Data System initiated from January 1, 1992 to June 30, 1997 were analyzed in a retrospective registry study of fungal infections (based on ICD9 Coding). Results: Dialysis patients had an age-adjusted incidence ratio for fungal infections of 9.80 (95% confidence interval (CI) 6.34–15.25)) compared to the general population in 1996 (the National Hospital Discharge Survey). Candidiasis accounted for 79% of all fungal infections, followed by cryptococcosis (6.0%) and coccidioidomycosis (4.1%). In multivariate analysis, fungal infections were associated with earlier year of dialysis, diabetes, female gender, decreased weight and serum creatinine at initiation of dialysis, chronic obstructive lung disease and AIDS. In Cox regression analysis the hazard ratio for mortality of fungal infections was 1.35 (95% CI 1.28–1.42). Conclusions: Dialysis patients were at increased risk for fungal infections compared to the general population, which substantially decreased patient survival. Female and diabetic patients were at increased risk for fungal infections. Although candidiasis was the dominant etiology of fungal infections, the frequency of cryptococcosis and coccidioidomycosis were higher than previously reported.
Soluble Osteopontin and Vascular Calcification in Hemodialysis Patients
Authors: Nitta Kosaku , Ishizuka Tsutomu , Horita Shigeru , Hayashi Tetsuo , Ajiro Akiko , Uchida Keiko , Honda Kazuho , Oba Takashi , Kawashima Akira , Yumura Wako , Kabaya Takashi , Akiba Takashi , Nihei Hiroshi
Published: April 2003

Background: Vascular calcification often occurs in patients with uremia. As osteopontin (OPN) is not only involved in the physiological but also the pathological calcification of tissues, OPN may be associated with the pathogenesis of aortic calcification in hemodialysis (HD) patients. Methods: We examined the expression of OPN in atherosclerotic aortas of HD patients. In addition, we performed a prospective longitudinal study by using CT scans to detect aortic calcifications and by measuring the plasma OPN concentration by ELISA in HD patients (20 men, 16 women; mean age 55.2 ± 21.3 years) and in healthy volunteers (18 men, 17 women; mean age 54.0 ± 13.2 years). Results: By immunohistochemical staining, OPN was abundantly localized in atherosclerotic plaques of HD patients. The macrophages surrounding the atheromatous plaques were identified as the OPN-expressing cells. We furthermore found that the concentration of soluble plasma OPN was significantly higher in HD patients as compared with the concentrations in age-matched healthy volunteers (837.3 ± 443.2 vs. 315.1 ± 117.4 ng/ml, p < 0.01). The OPN concentration was positively correlated with the aortic calcification index in HD patients (r = 0.749, p < 0.01). Conclusion: These data suggest that OPN, secreted by macrophages, plays a role in the calcification of atheromatous plaques in HD patients.
Language Acquisition in Young German- Speaking Children with Cochlear Implants: Individual Differences and Implications for Conceptions of a ‘Sensitive Phase’
Authors: Szagun Gisela
Published: April 2003

The acquisition of language was studied longitudinally in a sample of 22 German-speaking children with cochlear implants (mean implantation age 29 months) and a control group of 22 normally hearing children. Spontaneous speech samples were collected over 27–36 months, starting at the the one-word stage. Results indicate that grammatical progress as measured by mean length of utterance was slower for cochlear-implanted children. However, there were substantial individual differences in the cochlear-implanted group. While 10 cochlear-implanted children progressed at pace with normally hearing children, 12 cochlear-implanted children remained well behind. Cochlear-implanted children who showed fast progress at an early stage continued to make fast progress as time went on, and those who showed slow progress early on continued to progress slowly. Pre-operative hearing was a better predictor of subsequent linguistic growth than age at implantation. Increases in vocabulary were associated with grammatical progress in both groups.
The Premature Fetus: Not as Defenseless as We Thought, but Still Paradoxically Vulnerable?
Authors: Gunn A.J. , Quaedackers J.S. , Guan J. , Heineman E. , Bennet L.
Published: April 2003

Traditionally, it has been believed that the cardiovascular and hormonal responses to asphyxia in preterm fetuses are immature, and this immaturity contributes to their apparent vulnerability to neural injury. However, these data were derived from studies using relatively mild insults, which did not allow for the greater cardiac glycogen reserves and anaerobic capacity of the brain near midgestation. Here, we review the maturation of the cardiovascular and cerebrovascular and cerebral responses to asphyxia in experimental animals and how these relate to the apparent vulnerability of the human premature brain. Most such investigations have been performed in the chronically instrumental fetal sheep. Recent studies have demonstrated that the premature fetus has highly adaptive and relatively mature responses to asphyxia, and that in absolute terms the preterm brain is very resistant to asphyxial injury. These data suggest that the premature fetus is able to survive much more prolonged periods of asphyxia than the near- term fetus, but that, paradoxically, such survival is associated with exposure to prolonged periods of hypotension and hypoperfusion and consequently greater risk of severe neural damage.
Ultrastructural Changes in the Uterine Luminal and Glandular Epithelium during the Oestrous Cycle of the Marsupial Monodelphis domestica (Grey Short-Tailed Opossum)
Authors: Wick Regula , Kress Annetrudi
Published: April 2003

Ultrastructural changes in the endometrium associated with the oestrous cycle were studied in the South American marsupial Monodelphis domestica. The most conspicuous changes include the height and the differentiation of the uterine luminal and glandular epithelium, which consists of ciliated and non-ciliated cells. The glandular epithelium attains its maximum development during oestrus, the luminal epithelium at postoestrus. A distinct increase in the number of ciliated cells can be observed during pro-oestrus, reaching a maximum number at oestrus; this is followed by a process of deciliation. The presence of solitary cilia on the apices of non-ciliated cells is very conspicuous during all oestrous stages and can best be seen on the luminal epithelium. These findings differ from the observations in eutherian mammals, where solitary cilia are only found in the immature uterus or after ovariectomy. The secretory activity of non-ciliated cells of the luminal epithelium is hardly noticeable along the apical membrane and stains only very faintly with Alcian blue. The glandular epithelium cells are filled apically with exocytotic vesicles at oestrus and early postoestrus. However, in contrast to the cervical gland cells, they hardly stain with Alcian blue, indicating that mucins of a different type must be present. Mechanisms for the remodelling of the luminal and glandular epithelium are especially conspicuous at metoestrus and early pro-oestrus and include the presence of autolysosomes, residual bodies and apoptotic bodies. In the endometrial stroma, around the uterine glands, macrophages accumulate and attain a typical oestrous stage-dependent appearance during their phagocytotic activities.
Sphincteric Musculature of Female Canine Urethra in Comparison to Woman Including 3D Reconstruction
Authors: Stolzenburg Jens-Uwe , Dorschner Wolfgang , Postenjak Marijana , Salomon Franz-Viktor , Jurina Konrad , Do Minh , Neuhaus Jochen
Published: April 2003

The circular arranged sphincteric musculature of bladder neck of female dogs and women were studied histomorphologically. 3D reconstructions of the anatomy of the bladder neck improve the understanding of construction principles of the musculature of the lower urinary tract and help to compare both species. Our own investigations based on 12 adult female canine and 15 female human autopsy preparations. The special feature of our study was the extensive en bloc preparation of all the organs of the lower urinary tract and surrounding organs. The organ blocks were reprocessed in complete serial sections from the bladder outlet down to the bulb of vestibuli. Despite different detailed construction, in both species the striated sphincter musculature of the urethra is an independent morphological unit. There is no continuation of pelvic floor muscles to the urethra. In humans, the urethral sphincter consists of a smooth muscular part (m. sphincter urethrae glaber) and a striated part (m. sphincter urethrae transversostriatus). In the female dog, striated muscle fibres encircle the urethra in the middle third exclusively. In the distal third of the urethra, it encircles the urethra and the vagina. In the female dog, the lamellae of detrusor continue directly to the urethra. Throughout the cranial and middle third of the urethra, smooth muscle cell bundles form a homogenous compact sphincteric muscle originating from the middle circular layer of detrusor. In that way, no true bladder neck sphincter according to the m. sphincter vesicae in women exists in dogs. According to the smooth muscular part of the m. sphincter urethrae in women, for this musculature the term m. sphincter urethrae glaber is suggested. Despite a superficial resemblance, this study revealed a considerable difference of circular sphincteric muscle components between female dog and woman suggesting that functional studies in respect to urinary continence obtained in dogs cannot be attributed without qualification to humans.
Anatomical Partitioning of Three Human Forearm Muscles
Authors: Segal Richard L. , Catlin Pamela A. , Krauss Elizabeth W. , Merick Katherine A. , Robilotto Jessica B.
Published: April 2003

Anatomical partitioning has been found in the human biceps brachii, extensor carpi radialis longus and flexor carpi radialis muscles. The purpose of this study was to determine if the human extensor carpi ulnaris, flexor carpi ulnaris and flexor digitorum profundus are anatomically partitioned. Evidence for or against anatomical partitioning was obtained by observation of the architectural and innervation characteristics of each of the investigated muscles. Twelve samples (11 were used for extensor carpi ulnaris) of each specific muscle type were harvested from perfused human cadavers. The architectural characteristics of tendinous boundaries, muscle fiber direction, and muscle fiber angle magnitude were observed, measured and documented. Microdissection technique was used to investigate the primary nerve branching pattern throughout each muscle. A primary nerve branch to a specific muscle region indicated possible partitioning by innervation. The extensor carpi ulnaris was found to have a variable number of primary nerve branches. The extensor carpi ulnaris may have four partitions by innervation alone or three congruent partitions by innervation and muscle fiber architecture. The nerve to the flexor carpi ulnaris clearly innervates two architectural partitions within the muscle. The innervation pattern to the flexor carpi ulnaris is congruent with muscle fiber architecture characteristics indicating consistent anatomical partitioning within the flexor carpi ulnaris. Two muscle nerves innervate the flexor digitorum profundus with branches innervating the medial and lateral regions of the muscle. Up to eight architectural partitions were found in a medial-to-lateral direction.
Pruritus and Hydration State of Stratum corneum in Hemodialysis Patients
Authors: Kato Akihiko , Hamada Mayumi , Maruyama Takanori , Maruyama Yukitaka , Hishida Akira
Published: April 2003

Background: Xerosis is the most frequent cutaneous manifestation in hemodialysis (HD) patients, but the association between dry skin and pruritus remains to be clarified. Since the skin surface hygrometer can detect the changes of water content in the stratum corneum more sensitively, we re-examined the relationship between the severity of pruritus and water content in dialysis patients. Methods: Fifty patients who had been undergoing regular HD were examined for the degree of pruritus by clinical grading. Water contents in the stratum corneum at volar forearm and lower leg were assessed by measurement of high-frequency conductance using a skin surface hygrometer both at pre- and postdialysis. Results: Thirty-seven (74%) of dialysis patients complained of pruritus. High-frequency conductance values were significantly lower in HD patients compared to those of age-matched control subjects (n = 13) both at forearm (35.1 ± 3.0 vs. 73.3 ± 10.4 µS, p < 0.01) and lower leg (14.2 ± 1.1 vs. 52.4 ± 7.5 µS, p < 0.01). There was no relationship between the severity of pruritus and age, gender, HD duration, underlying renal disease, or removing fluid volume. A significant reduction of itching score was found in patients using polysulfone membrane. A single HD session using cellulose triacetate or polysulfone membrane significantly increased water content both at forearm and lower leg (p < 0.05). However, the degree of pruritus did not correlate with the skin water content both at the beginning and the end of HD session, respectively. Conclusion: It follows from these findings that water content in the stratum corneum was reduced in HD patients, but did not correlate with the severity of pruritus.
The Natural History of Leukocyturia Associated with Indinavir Treatment in HIV+ Individuals
Authors: Gagnon Raymonde F. , Tecimer Sandy N. , Watters Andrew K. , Hatzakis George E. , Tsoukas Christos M.
Published: April 2003

Urinary complications observed during indinavir treatment of HIV disease are often attributed to indinavir crystalluria. In a prospective study of urinalysis during the first year of indinavir therapy, 5 of 54 asymptomatic HIV+ individuals presented severe leukocyturia (≧100 cells/HPF) usually accompanying indinavir crystalluria. The clinical course of these 5 individuals, successfully treated for HIV and monitored for an second follow-up year, suggests that recurrence of severe leukocyturia may be an indicator of renal damage, likely tubulointerstitial disease caused by indinavir crystalluria. This is in contrast to the remaining 49 subjects, including those presenting mild leukocyturia, who did not demonstrate any evidence of renal disease. Regular urinalysis is therefore recommended in the clinical management of indinavir-treated individuals to detect early renal damage secondary to indinavir crystalluria and to prevent further renal impairment.
The BsmI Vitamin D Receptor Gene Polymorphism in Israeli Populations and in Perimenopausal and Osteoporotic Ashkenazi Women
Authors: Pollak Rivka Dresner , Blumenfeld Anat , Bejarano-Achache Idith , Idelson Maria , Hochner Drorith Celinker
Published: April 2003

Background: The association between vitamin D receptor (VDR) gene polymorphisms and bone mineral density (BMD) is controversial, and may be effected by ethnic ancestry and age. Aims: To determine the distribution of the BsmI VDR gene polymorphism in healthy Israeli populations, and to study its association with BMD in perimenopausal and osteoporotic Ashkenazi women. Methods: Allele and genotype frequencies of the VDR gene defined by BsmI restriction site were determined in 634 healthy Israelis of seven ethnic groups, 90 Ashkenazi perimenopausal women and in 75 Ashkenazi osteoporotic women. Genotype-related differences in spinal and femoral neck BMD were determined in Ashkenazi perimenopausal women. Allele and genotype frequencies in Ashkenazi osteoporotic women were compared with Ashkenazi controls. Results: The frequency of the BB genotype was higher in Yemenites compared with Ashkenazi and Libyan Jews (23, 11 and 8%, respectively, p < 0.05), and lower in Ashkenazi compared with Iraqi and Persian Jews (11, 20 and 21%, respectively, p = 0.05). BMD did not vary by genotype in perimenopausal women, nor were there differences in the frequencies of the B allele or the BB genotype in osteoporotic women compared with controls. Conclusions: There is ethnic variability in the frequency of the BsmI VDR gene polymorphism. In Ashkenazi perimenopausal and osteoporotic women this polymorphism is not associated with BMD.
Identifying Patients at Risk for Hemodialysis Underprescription
Authors: Leon Janeen B. , Sehgal Ashwini R.
Published: April 2003

Underprescription of hemodialysis is an important barrier to adequate delivery of dialysis. We sought to determine which patient factors are associated with hemodialysis underprescription and to examine variation in prescription across facilities. For 721 randomly selected patients from all 22 chronic hemodialysis units in northeast Ohio, we calculated prescribed Kt/V based on dialyzer urea clearance at prescribed blood and dialysate flow (K), prescribed treatment time (t), and anthropometric volume (V). A minimum ‘prescribed Kt/V’ of 1.3 has been recommended to ensure an adequate ‘delivered Kt/V’ of 1.2. Using this criterion, 15% of patients had a low prescribed Kt/V. Prescribed Kt was strongly related to patient anthropometric volume but not to other patient characteristics (age, gender, race, cause of renal failure, number of years on dialysis, number of comorbid conditions). A 10-liter increase in V was associated with an 8.3-liter increase in prescribed Kt. However, a 13-liter increase in prescribed Kt would be needed to maintain a prescribed Kt/V of 1.3. As a result, the proportion of patients with low prescriptions increased from 2% of patients with V <35 liters to 42% of patients with V ≧50 liters. In addition, the prevalence of low prescriptions varied dramatically across facilities (range 0–47%) even after accounting for volumes of individual patients. Of the 109 patients with low prescription, 75% would achieve a prescribed Kt/V of 1.3 with less than 30 min of additional treatment time. In conclusion, large patients and patients at specific facilities are at increased risk for underprescription of hemodialysis. Most patients with low prescriptions would achieve a prescribed Kt/V of 1.3 with a modest increase in treatment time.
Self-Assessed Quality of Life in Peritoneal Dialysis Patients
Authors: Mittal Sanjeev K. , Ahern Lauri , Flaster Edith , Mittal Vandana S. , Maesaka John K. , Fishbane Steven
Published: April 2003

Background/Aims: Studies comparing quality of life (QOL) between peritoneal and hemodialysis patients have yielded inconsistent results. Physical (PCS) and mental component summary (MCS) scales of Short Form 36 (SF-36) health survey are highly validated measures of self-assessed QOL. We sought to evaluate these indices in PD patients: (1) as measures of QOL, (2) predictors of QOL, (3) to study change in QOL over time, and (4) to compare QOL in PD vs. hemodialysis patients. Methods: SF-36 questionnaires were administered every 3 months to patients over a 2-year period and PCS and MCS were calculated. Mean follow-up was 15.3 ± 6.6 months for PD and 14.5 ± 5.7 months for HD. Results: Average PCS in PD (31.8 ± 7.8) was lower than HD (36.9 ± 9.8) (p < 0.02), while MCS was similar in the groups (p = NS). The prevalence of depression was 26.1% in PD and 25.4% in HD patients (p = NS). Serum albumin was the only significant predictor of PCS among PD patients and explained much of the decrease in PCS in them. The number of hospitalizations and in-hospital days were significantly lower for PD compared to HD patients (p < 0.05). PCS as well as MCS remained stable in both groups throughout the observation period. Conclusion: Self-assessed physical function is diminished, while mental function is similar in PD compared to HD patients. When corrected for serum albumin, this difference is eliminated. Over time, QOL in patients treated with PD remained stable.
Access Blood Flow as a Predictor of Early Failures of Native Arteriovenous Fistulas in Hemodialysis Patients
Authors: Kim Young Ok , Yang Chul Woo , Yoon Sun Ae , Chun Kyung Ah , Kim Nam Il , Park Jang Sang , Kim Byung Soo , Kim Yong Soo , Chang Yoon Sik , Bang Byung Kee
Published: April 2003

Blood flow imaging using color doppler has proven effective in predicting graft failures in hemodialysis patients, but its effect on native arteriovenous fistulas (AVF) is not well known. This study was performed to investigate whether measurements of the access blood flow can be used as predictors of an early failure of a native AVF in hemodialysis patients. Fifty-three consecutive patients who received native AVF operations were included in this study. Access blood flow was measured at 1 week after operations, and AVF function was followed for 4 months. During the follow-up, access failures developed in 10 patients at 9.8 ± 3.5 weeks. AVF blood flow was significantly lower in the failure group (n = 10) than in the patent group (n = 43) (450 ± 214 vs. 814 ± 348 ml/min, p = 0.003). The incidence of access failures was higher in the patients with a flow <350 ml/min (n = 9) compared to the patients with a flow >350 ml/min (n = 44) (55.5 vs. 11.3%, p = 0.008). The diameters of veins were significantly smaller in the failure group than in the patent group (3.5 ± 0.5 vs. 4.1 ± 0.7 mm, p = 0.018). The incidence of diabetes mellitus was higher in the failure group than in the patent group (90 vs. 51%, p = 0.025). However, age, sex, duration from an operation to first cannulation, and different AVF sites did not make a significant difference between the two groups. Our data suggest that access blood flow measurements using color doppler ultrasound during early postoperative periods are useful parameters in predicting an early failure of a native AVF in hemodialysis patients.
A Case Review: Anticoagulation in Hemodialysis Patients with Heparin-Induced Thrombocytopenia
Authors: Chuang Peale , Parikh Chirag , Reilly Robert F.
Published: April 2003

We describe a patient with acute renal failure who subsequently developed heparin-induced thrombocytopenia (HIT) while on hemodialysis. Heparin was immediately discontinued and alternative modes of anticoagulation were considered as further hemodialysis was indicated. With several options available, a review of the current literature was performed to aid in the selection of the most appropriate method. We conclude that there is currently no ideal hemodialysis anticoagulation agent for a patient with HIT. Among the currently available alternatives, no anticoagulation or regional citrate infusion during hemodialysis appears to be the most reliable and safest option for these patients. Based upon its safety, reversibility, low cost and availability, a trial of warfarin also may be attempted for hemodialysis anticoagulation. Both danapranoid and lepirudin have been used effectively in hemodialysis patients with HIT, but have the disadvantage of prolonged half-lives in patients with renal failure and relatively high cost.
Study of Lead Exposure from Automobile Exhaust as a Risk for Nephrotoxicity among Traffic Policemen
Authors: Mortada W.I. , Sobh M.A. , El-Defrawy M.M. , Farahat S.E.
Published: April 2003

Background: Traffic policemen are the most exposed population to lead (Pb) from automobile exhaust. There has been increasing concern about the possible harmful effects of Pb from automobile exhaust on health of traffic policemen. However, no such study was concerned with the impact of Pb exposure on renal function among them. Therefore, we aimed to study the effect of Pb exposure from automobile exhaust on renal integrity among traffic policemen. Methods: Markers of tubular damage [urinary excretion of β2-microglobulin (β2M), N-acetyl-β-D-glucosaminidase (NAG), alkaline phosphatase (ALP) and γ-glutamyl transferase (γ-GT)], a marker of glomerular injury (albuminuria), and markers of glomerular filtration [serum creatinine, serum β2M and blood urea nitrogen (BUN)] were determined in 43 traffic policemen (Pb-exposed group) and 52 matched healthy persons (control group). Pb levels in blood, urine, hair and nails were determined in the two groups as exposure indices of Pb. Results: The results obtained show that the Pb-exposed group had higher Pb levels in blood, urine, hair and nails than the controls. Among the Pb-exposed group, Pb levels in blood, hair and nails showed significant and positive correlations with the duration of exposure to Pb which is measured as the duration of employment. Among the studied markers of kidney damage, urinary excretion of NAG and albumin were significantly higher in the Pb-exposed group than in the controls. Urinary excretion of NAG was positively correlated with duration of exposure, blood Pb and nail Pb. Urinary albumin was positively correlated with duration of exposure, blood Pb and hair Pb. The other markers of kidney damage were neither elevated nor correlated with exposure indices of Pb. Conclusion: Traffic policemen are liable to Pb toxicity, and the determination of Pb in blood, hair and nails are good markers of such toxicity. In these exposure conditions, kidney damage is possible. Such damage is both tubular and glomerular in nature and can be documented by determination of the urinary excretion of NAG and albumin.
Induction of Transcription Factor AP-2 by Cytokines and Prostaglandins in Cultured Mesangial Cells
Authors: Suyama Kazuhide , Kabuyama Yukihito , Suzuki Shigeo , Kawasaki Yukihiko , Suzuki Junzo , Suzuki Hitoshi , Homma Yoshimi
Published: April 2003

Background/aims: Activator protein-2 (AP-2) is an important transcription factor for activation of growth- and inflammatory-associated genes. To detect AP-2 in the mesangium, the expression level of AP-2 was examined in cultured mesangial cells in response to various cytokines and prostaglandins. The level was also observed in kidney tissue samples obtained from patients with proteinuria and from a rat nephrosis model. Methods: AP-2 was immunohistochemically detected with a specific antibody. The expression level was analyzed by immunoblotting. Human tissue samples were obtained from patients with proteinuria. Kidney samples were also obtained from rats with puromycin aminonucleoside-induced nephrosis. Results: Pro-inflammatory cytokines, such as IL-6, IL-1 and IL-2, but not TNF-α, induced AP-2 expression in a time- and dose-dependent manner in cultured mesangial cells. PGE2 and PGI2 also induced AP-2 expression, while PGF2α failed to induce this protein. High expression levels of AP-2 were observed in different cell types including mesangial cells of kidney samples from patients with proteinuria. Similar results were obtained from the rat nephrosis model. Conclusion: These findings demonstrate that the primary cytokines induce AP-2 protein in mesangial cells. AP-2 may act as a transcription factor to produce additional cytokines and growth-associated gene products, suggesting an important role for AP-2 for the function of mesangial cells in glomerular disorders.
Cell-Crystal Interactions and Kidney Stone Formation
Authors: Lieske JohnC. , Deganello Sergio , Toback F.Gary
Published: April 2003

Background: Renal tubular fluid in the distal nephron is supersaturated with calcium and oxalate ions that nucleate to form crystals of calcium oxalate monohydrate (COM), the most common crystal in renal stones. How these nascent crystals are retained in the nephron to form calculi in certain individuals is not known. Methods: The results of experiments conducted in this and other laboratories that employ cell culture model systems to explore renal epithelial cell-urinary crystal interactions are described. Results: COM crystals rapidly adhere to anionic sites on the surface of cultured renal epithelial cells, but this process can be inhibited, if specific urinary anions such as glycosaminoglycans, uropontin, nephrocalcin, or citrate are available to coat the crystalline surface. Therefore, competition for the crystal surface between soluble anions in tubular fluid and anions on the apical cell surface could determine whether or not a crystal binds to the cell. A similar paradigm describes adhesion of calcium phosphate (hydroxyapatite) crystals, also a common constituent of human stones. Once bound, COM and hydroxyapatite crystals are quickly internalized by renal cells; reorganization of the cytoskeleton, alterations in gene expression, and initiation of proliferation may then ensue. Each of these cellular events appears to be regulated by a different set of extracellular factors. Over several weeks in culture, renal cells (BSC-1 line) dissolve internalized crystals, although once a cell binds a crystal, additional crystals are more likely to bind, possibly forming a positive feedback loop that results in kidney stone formation. Conclusions: Increased knowledge about the cell-crystal interaction, including identification of molecules in tubular fluid and on the cell surface that modulate the process, and understanding its mechanism of action appear critical for explaining the pathogenesis of nephrolithiasis.
Idiopathic Calcium Nephrolithiasis
Authors: Marangella Martino , Vitale Corrado , Bagnis Cristiana , Bruno Michele , Ramello Adriano
Published: April 2003

Calcium nephrolithiasis (CaNL) accounts for more than 70% of all renal stones, and its prevalence has increased in the last decades. Under this definition are included patients passing stones, composed of calcium oxalates and/or calcium phosphates. Current views of the pathogenesis of CaNL are based on the role of metabolic abnormalities which concur to render urines more conducive to crystallization. Therefore, the diagnostic approach is aimed at detecting these abnormalities, and the medical treatment assumes that a decrease in the risk of lithogenesis will result in remission or improvement of recurrences. The workup of the patients with CaNL begins with the analysis of passed stones and X-ray, sonography or other imaging techniques. Eligible patients, that is, both recurrent active stone formers and single-stone formers with individual risk factors, are considered for a metabolic evaluation, by which a number of blood and urine parameters are measured and others calculated. These include estimates of urine state of saturation with calcium and uric acid salts, net gastrointestinal alkali absorption, renal threshold of phosphate and other renal clearances and net acid and total nitrogen excretions. Basically, this screening is informative on renal function, metabolic abnormalities and their pathophysiology, risk of stone formation and dietary habits. During treatment it gives information about patient compliance and adverse effects of therapy. The cost of a comprehensive screening in Piedmont is 192,000 ITL (100 Euro) and rises to 300,000 ITL (154 Euro) if hormones and hydroxyproline are measured. In individual patients second- and third-level studies are performed, in order to detect systemic diseases which account for about 20% of CaNL in our series. Cost-to-benefit analysis has shown that the medical procedures for CaNL yield considerable saving in terms of difference between expenditure for drugs and testing and reduction of stone events. However, the current workup cannot be considered exhaustive, because misleading events may hamper the relation between laboratory findings and clinical outcome, and factors other than urine composition have appeared on the scenario of nephrolithiasis. These represent our challenge for the third millennium.
Hyperuricemic Nephropathies
Authors: Steele Thomas H.
Published: April 2003

This review explores the relationship between uric acid or urate and the pathogenesis of renal impairment. The following points and conclusions are emphasized: (1) uric acid is an end product of purine degradation in humans and normally depends upon renal excretion for the majority of its elimination from the body; (2) massive urate overproduction – usually occurring acutely because of tumor lysis, rhabdomyolysis, or some other cause of rapid nucleic acid turnover or tissue destruction – tends to cause acute renal failure because of an increase of intratubular uric acid precipitation and obstruction; (3) chronic urate overproduction (with increased urate excretion) is more likely to be associated with stones or gout than with acute renal failure; (4) chronic asymptomatic hyperuricemia is unlikely to cause renal disease, gout, or stones, but is associated with cardiovascular impairment over the long term, and (5) asymptomatic hyperuricemia may serve as an indicator of renal vascular disease, or, to the extent that it may reflect insulin-induced acceleration of renal tubule urate reabsorption, hyperuricemia may serve as an indicator of insulin resistance. Therefore chronic asymptomatic hyperuricemia may predict the adverse cardiovascular consequences of insulin resistance.
Correlation between the Severity of Clinicopathological Parameters and Whole Blood Interferon-α Production Capacity in Active Phase IgA Nephropathy Patients
Authors: Shirakawa Kiichi , Muso Eri , Nogaki Fumiaki , Maeda Mari , Kawamura Takahide , Ono Takahiko , Yoshimoto Miwa , Uno Kazuko , Kishida Tsunatarou , Sasayama Shigetake
Published: April 2003

Background/Aims: Patients with IgA nephropathy (IgA-N) are thought to have immune system disorders that frequently result in high serum IgA levels and a relatively high susceptibility to upper respiratory infections. Aims: To clarify the influence of the specific immune response of IgA-N patients on the clinicopathological features of the disease, we measured the whole-blood-producing capacity of interferon-α (IFNα-PC). We then compared these findings with clinical and histopathological parameters, including tissue macrophage infiltration, during both histologically active and latent phases. Patients and Methods: Fifty-one inpatients with IgA-N and 70 healthy controls were examined. According to the histological findings, 32 patients had disease in the active phase (AP), and 19 were in the latent phase (LP). Results: In AP patients, IFNα-PC showed positive correlations to serum creatinine, blood urea nitrogen, serum β2-microglobulin (s-β2MG), urinary total protein (U-TP), and urinary β2MG, in addition to the number of infiltrated macrophages per area of interstitium. In LP patients, negative correlations were shown between IFNα-PC and s-β2MG, U-TP, and U-N-acetyl-β-D-glucosaminidase. Conclusion: A significant positive relationship exists between IFNα-PC and the clinicopathological parameters of deteriorated renal lesions in the AP but not in the LP. Thus, the immune status influencing the functional damage may differ between these two phase.
Expression of Fc Gamma Receptor III (CD16) on Monocytes during Hemodialysis in Patients with Chronic Renal Failure
Authors: Kawanaka Norikuni , Nagake Yoshio , Yamamura Masahiro , Makino Hirofumi
Published: April 2003

Background/Aims: Circulating CD14+CD16+ monocytes, a potent phagocytosing and antigen-presenting monocyte population, have been reported to be expanded in patients on hemodialysis (HD). In this study, changes in the population of CD14+CD16+ monocytes were analyzed during a single session of HD therapy, and the influence of dialyzer membrane materials on these monocytes was investigated. Methods: Nine patients were hemodialyzed using regenerated cellulose (RC) membranes and thereafter polysulfone (PS) membranes. Peripheral blood cells were taken from these subjects, and these cells were stained with anti-CD14 and anti-CD16 antibodies. The percentages of CD14- and CD16-expressing monocytes were analyzed by two-color flow cytometric analysis. Moreover, the serum soluble CD14 (sCD14) levels were measured with an ELISA kit. Results: It was found that CD14+CD16+ monocytes before HD were significantly increased in patients on HD as compared to healthy controls. In the RC group, CD14+CD16+ monocytes were decreased at both 30 and 240 min after the initiation of HD. The reduction rate of CD14+CD16+ monocytes in the RC group was higher than that in the PS group. There was no significant difference in sCD14 levels between the two groups. Conclusion: Monocytes are activated in patients on HD. Furthermore, the population of CD14+CD16+ monocytes was stimulated to a greater extent during HD in the RC group than in the PS group. The significant reduction in CD14+CD16+ monocytes by RC membranes indicated that the level of CD14+CD16+ monocytes is a sensitive marker for the biocompatibility of HD membranes.