Clinical Impact of a Protocolized Kidney Donor Follow-up System

BACKGROUND

Adequate kidney donor management after donation is increasingly emphasized due to concerns of renal function impairment after nephrectomy with increasing life expectancy. In this study, the clinical impact of a protocolized kidney donor follow-up system by nephrologists was evaluated.

METHODS

A total of 427 living kidney donors underwent nephrectomy from January 2010 to December 2014 and were followed for at least 2 years at the Samsung Medical Center. Donors were followed-up by nephrologists after the establishment of a donor clinic with systemized protocols in January 2013. The primary outcomes were incidence of post-donation low estimated glomerular filtration rate (eGFR) and renal function adaptability. Secondary outcomes were changes in compliance and incidence of hyperuricemia and microalbuminuria.

RESULTS

The patients were divided into 2 groups according to the time of nephrectomy: the pre-donor clinic period (n = 182) and the donor clinic period (n = 172). Preoperative eGFR in patients in the pre-donor clinic period was higher than that in patients in the donor clinic period. After donation, poor renal adaptation was less frequent in the donor clinic period compared to the pre-donor clinic period. Low eGFR tended to be less common during the donor clinic period. Shorter mean outpatient clinic visit intervals with more visits within 6 months after donation and earlier detection of de novo hyperuricemia were found during the donor clinic period.

CONCLUSION

A protocolized donor clinic run by nephrologists may improve post-nephrectomy renal outcomes and compliance and facilitate better management of potential risk factors of chronic kidney disease in donors.

Predictive Factors of Renal Adaptation After Nephrectomy in Kidney Donors

BACKGROUND

Despite compensatory hyperfiltration in remaining nephrons following donor nephrectomy, some donors show impaired renal adaptation and low estimated glomerular filtration rate (eGFR). We investigated the factors predicting early renal adaptation after nephrectomy and identified kidney donors at risk of inadequate renal adaptation.

METHODS

A total of 265 living kidney donors from 2010 to 2013 were retrospectively analyzed. Renal function was serially followed for 6 months after the operation. Regression analyses were performed to identify the independent predictors of low eGFR (eGFR <60 mL/min/1.73 m²) and impaired renal adaptation (%Modification of Diet in Renal Disease [MDRD] <66% of baseline eGFR).

RESULTS

A total of 148 donors belonged to the low eGFR group, and changes in eGFR (ΔeGFR) at postoperative (PO) 1 day and 1 month were identified as independent predictors of low eGFR. Impaired renal adaptation was related to age, ΔeGFR PO 2-3 days, and ΔeGFR PO 1 month. Early renal adaptation was associated with age, male gender, and residual kidney computerized tomography angiography (CTA) volume. The best sensitivity and specificity were obtained with a cutoff value of ΔeGFR 31 at PO 1 day and 1 month for predicting low eGFR and with a value of ΔeGFR 27 at PO 2-3 days and 1 month for predicting impaired renal adaptation.

CONCLUSIONS

Our study showed that the degree of early renal adaptation determines subsequent renal function in kidney donors. Closer monitoring and management may be required in old or male donors with small residual CTA kidney volume as well as donors with persistent ΔeGFR >27 within 1 month of nephrectomy.

The association of uterine cervical microbiota with an increased risk for cervical intraepithelial neoplasia in Korea

Recent studies have suggested potential roles of the microbiome in cervicovaginal diseases. However, there has been no report on the cervical microbiome in cervical intraepithelial neoplasia (CIN). We aimed to identify the cervical microbiota of Korean women and assess the association between the cervical microbiota and CIN, and to determine the combined effect of the microbiota and human papillomavirus (HPV) on the risk of CIN. The cervical microbiota of 70 women with CIN and 50 control women was analysed using pyrosequencing based on the 16S rRNA gene. The associations between specific microbial patterns or abundance of specific microbiota and CIN risk were assessed using multivariate logistic regression, and the relative excess risk due to interaction (RERI) and the synergy index (S) were calculated. The phyla Firmicutes, Actinobacteria, Bacteroidetes, Proteobacteria, Tenericutes, Fusobacteria and TM7 were predominant in the microbiota and four distinct community types were observed in all women. A high score of the pattern characterized by predominance of Atopobium vaginae, Gardnerella vaginalis and Lactobacillus iners with a minority of Lactobacillus crispatus had a higher CIN risk (OR 5.80, 95% CI 1.73-19.4) and abundance of A. vaginae had a higher CIN risk (OR 6.63, 95% CI 1.61-27.2). The synergistic effect of a high score of this microbial pattern and oncogenic HPV was observed (OR 34.1, 95% CI 4.95-284.5; RERI/S, 15.9/1.93). A predominance of A. vaginae, G. vaginalis and L. iners with a concomitant paucity of L. crispatus in the cervical microbiota was associated with CIN risk, suggesting that bacterial dysbiosis and its combination with oncogenic HPV may be a risk factor for cervical neoplasia.

Assessment of extent of breast cancer: comparison between digital breast tomosynthesis and full-field digital mammography

AIM

To compare the accuracy of digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) in preoperative assessment of local extent of breast cancer.

MATERIALS AND METHODS

Lesion sizes of breast cancers on DBT and FFDM images were independently evaluated by breast radiologists. Each lesion was flagged as either mis-sized or not depending on whether the assessment of size at imaging was within 1 cm of the lesion size at surgery. Additional analyses were made by mammographic parenchymal density and by lesion size, using 2 cm as the boundary to separate the two subgroups. Statistical comparisons were performed using a repeated measures linear model on the percent mis-sized. P-values < 0.05 were considered statistically significant.

RESULTS

The dataset included 173 malignant breast lesions (mean size 23.8 mm, 43% of lesions were ≤2 cm in size) in 169 patients, two-thirds of which had heterogeneously or extremely dense breasts. Overall, the percentage of lesions mis-sized at DBT was significantly lower than at FFDM (19% versus 29%, p = 0.003). There was significantly less mis-sizing at DBT in both heterogeneously dense breasts (11.1% difference between DBT and FFDM, p = 0.016) and extremely dense breasts (15.8% difference, p = 0.024). DBT also had significantly less mis-sizing than FFDM in the subgroup of lesions that were ≤2 cm in size (14.7% difference, p = 0.005).

CONCLUSION

DBT was significantly superior to FFDM for the evaluation of lesion size overall, and specifically for small lesions and for lesions in dense breasts. The superiority of DBT versus FFDM increased with parenchymal density.

Hormonal differences between female kidney transplant recipients and healthy women with the same gynecologic conditions

BACKGROUND

End-stage renal disease is associated with severe abnormalities in reproductive function. However, the abnormalities are reversed by successful kidney transplantation. The aim of the present study was to compare hormonal levels between recipients with successful kidney transplantations and healthy women with the same gynecologic conditions.

METHODS

The study group consisted of 31 women of reproductive age with end-stage renal disease who underwent successful kidney transplantation. The ratio of the control group, composed of healthy woman, to the study group was 3:1 matched for age and symptoms.

RESULTS

Abnormal bleeding (n = 14) and infertility were the most common gynecologic conditions in kidney transplant recipients. The levels of estrogen (E2) and follicle-stimulating hormone (FSH) in the study group were higher than in the control group, but the levels of progesterone (P4) and luteinizing hormone (LH) were lower in the study group than in the control group. There were no significant differences in prolactin and thyroid-stimulating hormone between the two groups. The incidence of infertility in patients who receive steroid was higher than those with no steroid use (P = .007).

CONCLUSIONS

Compared with healthy age- and symptom-matched women, female kidney transplant recipients have increased levels of E2 and FSH and decreased levels of P4 and LH. These differences in hormone profiles may predispose kidney transplant recipients to increased risk of gynecologic pathologies.

Comparison between thymoglobulin and ATGAM as an induction agent in adult kidney transplantation: a single-center experience

OBJECTIVE

The best antithymocyte globulin (ATG) preparation for induction suppression in kidney transplant recipients is still not clear. The aim of this study was to identify short- and long-term outcomes in kidney transplant recipients who received thymoglobulin or ATGAM as an induction agent.

METHODS

We retrospectively reviewed patients who underwent kidney transplantation from 1996 to 2010. Recipients were classified according to the ATG preparation.

RESULTS

One hundred fifty-two patients (64.4%) received thymoglobulin and 84 (35.6%) received ATGAM. The occurrence of delayed graft function in patients receiving thymoglobulin was higher than in patients receiving ATGAM (P = .005), but serum creatinine levels and acute rejection after kidney transplantation were not different between the two groups. The death-censored graft survival curve in thymoglobulin recipients was higher than in ATGAM recipients (P = .027). Bacterial infection was a predisposing factor for graft survival (P = .008).

CONCLUSION

The efficacy of thymoglobulin induction is generally better than that of ATGAM induction, and prevention of bacterial infections was just as important as the use of ATG because bacterial infection was an important risk factor for graft failure.

The incidence and clinical outcome of YMDD mutants in hepatitis B surface antigen-positive renal allograft recipients after prolonged lamivudine therapy

Although lamivudine (LAM) is a potent inhibitor of hepatitis B virus (HBV), prolonged therapy may induce the development of LAM-resistant strains, YMDD mutants. Although YMDD mutants have impaired replication that leads to a benign clinical course compared with wild-type virus, some immunosuppressive agents may enhance replication of YMDD mutants, causing a severe hepatitis flare. We retrospectively investigated the incidence and clinical outcomes of YMDD mutants in renal allograft recipients on immunosuppressive treatment. Clinical records of 25 renal allograft recipients, who underwent renal transplantation between December 1997 and February 2006 were hepatitis B surface antigen positive at the time of transplantation, were reviewed. All patients received LAM treatment after renal transplantation. Over 9 to 98 months of follow-up, 16 patients (64.0%) maintained undetectable HBV DNA levels; however, 9 patients (36.0%) showed persistent or increased levels of HBV DNA. Seven were identified as having developed YMDD mutants. Although genotypic analysis was not performed, YMDD mutants were strongly suspected in another two patients, who developed severe hepatic dysfunction combined with high levels of HBV viremia at close to 2 years of LAM therapy. One patient recovered after hepatic transplantation and another patient died of hepatic failure. In conclusion, the incidence of YMDD mutants was similar to that of nonimmunosuppressed individuals; however, the presence of these mutants made it more likely for severe liver disease to develop in renal transplant recipients. Therefore, close monitoring for the development of YMDD mutants should be performed during LAM treatment, especially in this group of patients.

Dexamethasone protects primary cultured hepatocytes from death receptor-mediated apoptosis by upregulation of cFLIP

Dexamethasone (DEX) pretreatment protected hepatocytes from TNF-alpha plus actinomycin D (ActD)-induced apoptosis by suppressing caspase-8 activation and the mitochondria-dependent apoptosis pathway. DEX treatment upregulated cellular FLICE inhibitory protein (cFLIP) expression, but did not alter the protein levels of Bcl-2, Bcl-xL, Mcl-1, and cIAP as well as Akt activation. The increased cFLIP mRNA level by DEX was inhibited by ActD, indicating that DEX upregulates cFLIP expression at the transcriptional step. DEX also inhibited Jo2-mediated hepatocyte apoptosis by blocking the formation of the death-inducing signaling complex and caspase-8 activation. Specific downregulation of cFLIP expression using siRNA reversed the antiapoptotic effect of DEX by increasing caspase-8 activation. Moreover, DEX administration into mice increased cFLIP expression in the liver and prevented Jo2-induced hepatic injury by inhibiting caspase-8 and -3 activities. Our results indicate that DEX exerts a protective role in death receptor-induced in vitro and in vivo hepatocyte apoptosis by upregulating cFLIP expression.

Effect of panel-reactive antibody positivity on graft rejection before or after kidney transplantation

INTRODUCTION

Because it is well known that kidney transplant recipients with preformed lymphocytotoxic antibodies against HLA antigens have increased graft rejection rates, a serological crossmatch is routinely performed before kidney transplantation. But, the presence of these antibodies is not routinely monitored after transplantation. We investigated the panel-reactive antibody (PRA) response to know whether variations before or after kidney transplantation were associated with graft rejection.

METHODS

We prospectively analyzed sera from 350 renal allograft recipients from September 1998 to March 2003. Pretransplantation and posttransplantation sera at 3 or 5 weeks postoperatively were tested in PRA. Recipients were stratified into 3 groups according to their PRA levels group I, PRA = 0; group II, PRA = less than 50%, and group III, PRA = more than 50%.

RESULTS

The total graft rejection rate among 350 recipients was 9.4% (n = 33). Twenty-four pretransplantation PRA-positive recipients had a graft rejection rate of 20.8% (n = 5), compared with an 8.6% (n = 28) rate among 326 pretransplantation PRA-negative recipients. Six of 24 posttransplantation PRA-positive recipients (25%) experienced a graft rejection versus 27 (8.3%) of 326 posttransplantation PRA-negative subjects. Among the pretransplantation PRA stratae, the rejection rate in group III was 25% (1 of 4) versus 20% (4 of 20) in group II and 8.6% (28 of 326) in group I (P < .05). According to the postransplantation PRA level, 37.5% (3 of 8) in group III versus 18.8% (3 of 16) in group II and 8.3% (27 of 326) in group I (P < .05) had a graft rejection.

CONCLUSION

Our study suggests that the PRA response pretransplantation and in the early posttransplantation period correlates with the kidney allograft rejection rate.

Randomized trial of tacrolimus versus cyclosporine in steroid withdrawal in living donor renal transplant recipients

The introduction of new immunosuppressants has prompted trials of steroid withdrawal. However, several groups have reported a higher incidence of rejection. We conducted a randomized two-arm, parallel-group, open-label, prospective study to compare steroid withdrawal (at 6 months posttransplant) from the regimens of tacrolimus + mycophenolate mofetil (MMF) (FK group) versus cyclosporine + MMF (CSA group). The entry criteria were recipients of first living donor transplants with no diabetes mellitus (DM), congestive heart failure, chronic liver disease, or acute rejection within 6 months posttransplant. The primary endpoint was a biopsy-proven acute rejection episode or treatment failure within 1 year posttransplant. While 87 recipients were assigned to FK (n = 43) and CSA groups (n = 44) before transplantation, 76 recipients (FK 39, CSA 37) could be tapered off steroids at 6 months posttransplant, since 11 were excluded due to acute rejection within 6 months posttransplant (FK two, CSA three) or protocol violations (FK two, CSA four). After steroid withdrawal, the incidence of acute rejection episodes was 0% in the FK group and 13.5% in the CSA group (P < .05). Other results at 12 months posttransplantation were comparable: the incidences of DM 7.8% versus 0% (FK group vs CSA group), hypercholesterolemia 41.0% versus 59.5%, hypertensives 48.7% versus 59.6% as well as the levels of plasma creatinine 1.21 +/- 0.24 versus 1.31 +/- 0.50 mg/dL (P > .05 in every variable). These data suggest that steroid withdrawal is successful in first living donor renal transplant recipients. Tacrolimus may be significantly more effective than cyclosporine to prevent acute rejection after steroid withdrawal.

Prognostic factors affecting graft and patient survival in cadaveric and living kidney transplantation

Numerous studies have reported various prognostic factors that affect graft and patient survival in living and cadaveric donor kidney transplantation (KT). The purpose of this study was to evaluate the clinical outcomes and prognostic factors affecting graft and patient survivals in living and cadaveric donor KT. Between February 1995 and December 2001, 421 patients who had undergone cadaveric donor KT (group I: 216 cases, 51.3%) or living donor KT (group II: 205 cases, 48.7%), were retrospectively analyzed. Five-year overall graft survival rates in living was significantly better than that in cadaveric donor KT, respectively (P = .0234). There was no difference in patient survival rates between the two groups. Such factors as absence of rejection, female donor, female recipient, adult KT according to recipient age (>14 years), and donor serum creatinine level just before transplantation (< 2.5 mg/dL) were significantly associated with good graft survival among cadaveric donor KT, whereas two factors-absence of rejection and adult KT according to recipient age (>14 years)-influenced graft survival in living donor KT. In multivariate analysis, the only significant prognostic factor related to graft survival was the presence of rejection. In conclusion, we suggest that the presence of rejection is the only factor that impairs graft survival in both cadaveric and living donor KT, while other factors affected graft survival differently in the two groups.

Polymerase chain reaction for the diagnosis of human polyomavirus-associated nephropathy in renal transplant recipients

Human polyomavirus type BK may be related to interstitial nephropathy or renal-allograft dysfunction. Patients with nephropathy due to infection with human polyomavirus may be identified early using the polymerase chain reaction(PCR). We attempted to evaluate whether the positive response in the PCR test of BK virus DNA in the plasma of renal transplant recipients affects the function of the renal allograft. Seventy-seven patients were prospectively analyzed according to the operative sex, age, sources of allograft, serum creatinine levels during PCR test for BK virus, postoperative type of immunosuppressant, and presence of graft rejection. Two groups were distinguished according to the PCR result for BK virus: group 1 (n = 12) positive PCR reaction and group 2 (n = 65) negative reaction. The mean follow-up was 32.6 weeks. The incidence of positive PCR tests for BK virus replication after renal transplantation was 15.6%. Decoy cells in the urine were detected in 20.7%. The incidence of BK virus nephropathy was 1.3%. The mean serum creatinine levels of group 1 and 2 at the time of the PCR tests were 1.34 and 1.22, respectively. The rejection rates in group 1 and 2 were 8% and 4.5%, respectively (P > .05). We consider that a PCR assay to detect BK virus in renal recipients blood may be useful to identify patients at risk for nephropathy. It may serve as a noninvasive indicator of BK virus replication, although this study is limited by the short follow-up and small numbers.

Cadaveric renal transplantation in hepatitis B antigen–positive recipients using hepatitis B antigen–positive donor organs with lamivudine treatment

Although renal transplantation has been regarded as the best renal replacement therapy in end-stage renal disease patients, there have never been enough organ donors. Therefore, hepatitis B surface antigen (HBsAg)-negative patients are often given priority over HBsAg-positive patients. We performed cadaveric renal transplantation in six HBsAg-positive recipients given HBsAg-positive donor organs who were on lamivudine treatment. Donors were found to have normal renal function by serum and urine laboratory tests. All recipients underwent liver biopsies before transplantation; those with liver cirrhosis were excluded. All recipients were treated with 100 mg lamivudine once daily because of positive titers of hepatitis B viral (HBV) DNA (three patients), and increased levels of alanine aminotransferase (ALT) (three patients). During the follow-up period, one patient died from hepatic failure at 50 months after transplantation without deterioration of graft function. The remaining five patients showed sustained normal ALT levels. Decreases in HBV DNA titer were observed among patients who were positive before transplantation, but did not reverse to negative. Acute rejection developed in two patients: one was treated successfully with steroid pulse therapy, and the other had two bouts of acute rejection within a 33-month interval. The first was successfully treated with steroid pulse therapy, but the second failed. The four remaining patients have maintained normal renal function for a considerable time. HBsAg-positive donor organs must be used carefully in renal transplantation of HBsAg-positive recipients.

Infectivity of in vitro transcripts of Johnsongrass mosaic potyvirus full-length cDNA clones in maize and sorghum

In vitro transcripts of full-length cDNA clones of the Johnsongrass strain of Johnsongrass mosaic potyvirus (JGMV-Jg) were infectious on maize and sorghum when inoculated by mechanical or by biolistic bombardment. Two of the cDNA clones with spontaneous mutations in the coat protein were not infectious. Sequence differences between infectious and non-infectious transcripts revealed that alteration of inferred amino sequences, near or in the N-terminus of the coat protein, profoundly affected the infectivity of transcripts. Transcripts of chimeric full-length cDNA of JGMV-Jg, containing coat protein sequences from the Krish-infecting strain of JGMV, were infectious in Krish resistant sorghums.

Genetic analysis of Nicotiana pollen-part mutants is consistent with the presence of an S-ribonuclease inhibitor at the S locus

Self-incompatibility (SI) is a genetic mechanism that restricts inbreeding in flowering plants. In the nightshade family (Solanaceae) SI is controlled by a single multiallelic S locus. Pollen rejection in this system requires the interaction of two S locus products: a stylar (S)-RNase and its pollen counterpart (pollen S). pollen S has not yet been cloned. Our understanding of how this gene functions comes from studies of plants with mutations that affect the pollen but not the stylar SI response (pollen-part mutations). These mutations are frequently associated with duplicated S alleles, but the absence of an obvious additional allele in some plants suggests pollen S can also be deleted. We studied Nicotiana alata plants with an additional S allele and show that duplication causes a pollen-part mutation in several different genetic backgrounds. Inheritance of the duplication was consistent with a competitive interaction model in which any two nonmatching S alleles cause a breakdown of SI when present in the same pollen grain. We also examined plants with presumed deletions of pollen S and found that they instead have duplications that included pollen S but not the S-RNase gene. This finding is consistent with a bipartite structure for the S locus. The absence of pollen S deletions in this study and perhaps other studies suggests that pollen S might be required for pollen viability, possibly because its product acts as an S-RNase inhibitor.

Medullary nephrocalcinosis associated with long-term furosemide abuse in adults

BACKGROUND

The use of furosemide is well recognized as a predisposing factor of nephrocalcinosis in infants. Although furosemide is widely used for various medical conditions in adults, its association with nephrocalcinosis in adults is not well established.

METHODS

We studied 18 consecutive adult patients (male:female ratio 1:17, age range 21-59 years) who habitually took furosemide to control weight or oedema for long periods of time (range 3-25 years). The daily dose of continuous intake of furosemide ranged from 40 to 2800 mg. Nephrocalcinosis was evaluated using renal ultrasonography (US), computed tomography (CT), or kidney biopsies.

RESULTS

Renal US and CT revealed bilateral nephrocalcinosis of the medullary pyramids in 15 (83.3%) out of 18 patients. The duration of furosemide abuse was similar between nephrocalcinosis positive (NC(+)) and nephrocalcinosis negative (NC(-)) groups. The daily dose of furosemide was nearly 10 times higher in the NC(+) group (range 120-2800 mg, mean 538 mg) than the NC(-) group (range 40-80 mg, mean 67 mg). All patients showed variable degrees of renal insufficiency and there was no difference in creatinine clearance between the NC(+) and NC(-) groups (P>0.05). Kidney biopsies performed in three patients showed focal tubulo-interstitial fibrosis and atrophy and calcifications were observed in outer medullary tubulo-interstitium.

CONCLUSIONS

Long-term furosemide abuse can cause medullary nephrocalcinosis in adults, and the risk of developing of nephrocalcinosis seems to be correlated with the daily dose of furosemide. We suggest that long-term furosemide abuse should be suspected in adult patients when medullary nephrocalcinosis is incidentally detected by US or CT.

Dissociation between clearances of small and middle molecules in incremental peritoneal dialysis

OBJECTIVE

To evaluate the peritoneal clearance of middle molecules in comparison with the peritoneal clearance of small molecules in incremental peritoneal dialysis (PD).

STUDY DESIGN

Peritoneal clearances of creatinine and beta2-microgloblulin (B2M) were compared in 57 continuous ambulatory PD patients on full dose of 4 exchanges, and 54 incremental PD patients with 2 or 3 exchanges over 24 hours. Clearances were also compared when there were changes in the PD regimen, such as in the number of exchanges and the duration of the dwell time.

SETTING

Tertiary-care university hospital.

RESULTS

Peritoneal creatinine clearance increased almost linearly with the increase in the number of exchanges. In contrast, peritoneal clearance of B2M was 9.1 +/- 3.6 L/week, 8.8 +/- 4.4 L/week, and 7.9 +/- 2.5 L/week with 2,3, and 4 exchanges, respectively, per day, amounts that were not different from each other. Peritoneal clearance of B2M did not change when there was an increase in the number of dialysate exchanges from 2 to 3 and from 3 to 4 over a period of 24 hours; whereas the peritoneal clearance of creatinine increased. Peritoneal clearance of B2M almost doubled, from 5.4 +/- 2.7 L/week with 2 exchanges over 12 hours per day, to 9.5 +/- 4.4 L/week with the same 2 exchanges over 24 hours. The creatinine clearance did not change.

CONCLUSION

In contrast to peritoneal clearance of small molecules, such as creatinine, which was dependent on the number of dialysate exchanges, peritoneal clearance of middle molecules, such as B2M, depended mainly on the total dwell hours of PD and not on the number of exchanges of peritoneal dialysate in incremental PD. This might be another advantage of incremental PD, since peritoneal clearance of middle molecules in incremental PD over 24 hours can be comparable to that in full dose PD.

Identification of mutations including de novo mutations in Korean patients with hypokalaemic periodic paralysis

BACKGROUND

Hypokalaemic periodic paralysis (hypoPP) is an autosomal dominant disorder involving the abnormal function of ion channels and it is characterized by paralysis attacks of varying severity, accompanied by a fall in blood potassium levels. Linkage analysis showed that the candidate locus responsible for hypoPP was localized to chromosome 1q31-32, and this locus encoded the muscle dihydropyridine-sensitive calcium channel alpha(1)-subunit (CACNA1S). So far, three different mutations in CACNA1S gene have been identified in patients with hypoPP: Arg528His, Arg1239His and Arg1239Gly in Caucasian patients. However, there are few reports about the mutations of CACNA1S gene in other races.

METHODS

In this study, four Korean families with five hypoPP patients were screened for mutations of CACNA1S gene with polymerase chain reaction-based restriction analysis and single-strand conformation polymorphism analysis. To determine the mode of inheritance, haplotype analysis was done with three microsatellite markers (D1S1726, CACNL1A3, and D1S1723).

RESULTS

Arg528His mutation was detected in three families, and one family had no known mutations. Moreover, for the first time, we detected de novo Arg528His mutations in two out of three families with hypoPP. Haplotype analysis using three microsatellite markers (D1S1726, CACNL1A3, and D1S1723) suggested the occurrence of de novo Arg528His mutations in two of the three families with Arg528His mutation.

CONCLUSIONS

Arg528His mutations of CACNA1S, including de novo Arg528His mutations, were found in Korean patients with hypoPP. These results imply that de novo mutation, in addition to non-penetrance, is one of the genetic mechanisms that can explain the previous clinical observation that hypoPP occurs sporadically without family history.

Usefulness of genetic susceptibility and biomarkers for evaluation of environmental health risk

Recent attention is focused on understanding the genetic basis for individual susceptibility to the development of chronic disease. An emphasis is concentrated on establishing an association between inheritance of polymorphic chemical metabolizing genes and development of environmental cancer (e.g., lung cancer among cigarette smokers). The early reports of such associations have been very encouraging. However, some reported positive associations were not substantiated in subsequent studies using larger sample sizes and different ethnic populations. In this review, some confounding factors that contribute to the discrepancies are presented (e.g., ethnic-dependent distribution of variant gene alleles, differential expression of metabolizing genes, and inadequate study design). It is possible that the precision of the association can be improved if the mentioned investigations are complemented with concurrent studies of biological activities/effects. The usefulness of integrating metabolic susceptibility with biomarker measurement for understanding the development of lung cancers is presented. The importance of using adequate sample size and experimental design is emphasized. Development of a reliable approach for prediction of environmental disease not only will provide fundamental information regarding the genetic basis of human disease but will be useful for reducing disease burden in the population and for advancing patient care. Environ. Mol. Mutagen. 37:215-225, 2001. &copy 2001 Wiley-Liss, Inc.

Morphologic evaluation and integrin expression profile of renal tubular cells cultured from percutaneous renal biopsy specimen

Kidney biopsy is an indispensible procedure for making a pathologic diagnosis of renal diseases by fixing and staining the biopsy specimen. However, it is not a routine procedure to culture the cells from a renal biopsy specimen directly, or to utilize the cultured cells for any kind of diagnostic or functional evaluation. In this study, primary culture of the renal tubular epithelial cells was tried from a piece of percutaneous kidney biopsy specimen. Successive passages of the cells were possible until fourth passage. With these cells, morphologic characteristics of the cultured cells and integrin expression profiles were investigated. On light and electron microscopy, these cells were characterized by the cobblestone-like growth, presence of microvilli and tight junction, and the preservation of polarity. Immunohistochemical studies demonstrated the epithelial nature of these cells and particularly their differentiation from renal tubular epithelial cells, of either proximal or distal nephronic segment. The integrin profile confirms the epithelial nature of the cell. We hope that our results facilitate the understanding of pathophysiology of renal tubular cells from the patient directly.

Variant metabolizing gene alleles determine the genotoxicity of benzo[a]pyrene

Understanding the mechanisms involved with genetic susceptibility to environmental disease is of major interest to the scientific community. We have conducted an in vitro study to elucidate the involvement of polymorphic metabolizing genes on the genotoxicity of benzo[a]pyrene (BP). Blood samples from 38 donors were treated with BP and the induction of sister chromatid exchanges (SCE) and chromosome aberrations (CA) were evaluated. The latter is based on the tandem-probe fluorescence in situ hybridization (FISH) assay. The data indicate that the induction of genotoxicity was clearly determined by the inherited variant genotypes for glutathione-S-transferase (GSTM1) and microsomal epoxide hydrolase (EH). In a comparison of the two biomarkers, the CA biomarker shows a more definite association with the genotypes than does SCE. For example, the presence of the GSTM1 null genotype (GSTM1 0/0) is responsible for the highest level and significant induction of CA, irrespective of the presence of other genotypes in the different donors. This effect is further enhanced significantly by the presence of the excessive activation EH gene allele (EH4*) and decreased by the reduced activation EH gene allele (EH3*). Overall, the modulation of genotoxicity by the susceptibility genotypes provides support of their potential involvement in environmental cancer. Furthermore, the data indicate that the variant enzymes function independently by contributing their metabolic capability toward the expression of biologic activities. Therefore, studies like this one can be used to resolve the complexity of genetic susceptibility to environmental disease in human.

Biomarker monitoring for health risk based on sensitivity to environmental mutagens

Ongoing human and environmental genome programs have generated a tremendous amount of information regarding the genetic basis for human disease. The information can be used to enhance existing bioassays, as well as to develop new bioassays for improving human monitoring with the goal of disease prevention. In this review, some biomarkers that can be used for the purpose are presented, with an emphasis on using biomarkers to monitor human sensitivity to environmental mutagens. The application of biomarkers in clarifying the role of inherited and acquired susceptibility for developing environmental disease will be discussed. We emphasize the use of biomarkers that can detect mutagen sensitivity and DNA repair deficiency in the humans as an indication of susceptibility to disease. Such sensitivity can be either genetically determined or acquired from the exposure to environmental mutagens.

Identification and characterization of nitric oxide synthase in Salmonella typhimurium

The presence of the nitric oxide synthase (NOS) enzyme from Salmonella typhimurium (S. typhimurium) was identified by measuring radiolabeled L-[3H]citrulline and NO, and Western blot analysis. NOS was partially purified by both Mono Q ion exchange and Superose 12HR size exclusion column chromatography, sequentially. The molecular weight of NOS was estimated to be 93.3 kDa by Western blot analysis. The enzyme showed a significant dependency on the typical NOS cofactors; an apparent Km for L-arginine of 34.7 mM and maximum activity between 37 degrees C and 43 degrees C. The activity was inhibited by NOS inhibitors such as aminoguanidine and N(G),N(G)-dimethyl-L-arginine. Taken together, partially purified NOS in S. typhimurium is assumed to be a different isoform of mammalian NOSs.

Modulation of chemical carcinogen-induced unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) in the primary rat hepatocytes

Modulation of unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) after exposure to various chemical carcinogens was investigated in the primary rat hepatocytes. Unscheduled DNA synthesis was induced by treatment of such direct acting carcinogens as methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) or procarcinogens including benzo(a)pyrene (BaP) and 7,12-dimethylbenz(a)anthracene (DMBA). Unscheduled DNA synthesis was determined by measuring [methyl-3H]thymidine radioactivity incorporated into nuclear DNA of hepatocytes treated with carcinogens in the presence or absence of DHEA. Hydroxyurea (5x10(-3) M) was added to growth medium to selectively suppress normal replication. DHEA at concentrations ranging from 1x10(-6) M to 5x10(-4) M did not significantly inhibit unscheduled DNA synthesis induced by either MMS (1x10(-4) M) or EMS (1x10(-2) M). In contrast, DHEA significantly inhibited unscheduled DNA synthesis induced by BaP (6.5x10(-5) M) and DMBA (2x10(-5) M). DHEA-induced hepatotoxicity in rats was examined using lactate dehydrogenase (LDH) release as an indicator of cytotoxicity. DHEA exhibit no significant increase in LDH release compared with the solvent control at 18 h. These data suggest that nontoxic concentration of DHEA does not affect the DNA excision repair process, but it probably influence the enzymatic system responsible for the metabolic activation of procarcinogens and thereby decreases the amount of the effective DNA adducts formed by the ultimate reactive carcinogenic species.

A multiplex-PCR/RFLP procedure for simultaneous CYP2E1, mEH and GSTM1 genotyping

Inter-individual variation in metabolism of environmental toxicants, which is attributed to genetic polymorphism, may be a major risk factor in determining who will develop adverse health effects. This priority research area is the focus of many laboratories, and new techniques need to be developed to enhance the efficiency in generating data. We have developed and validated a new multiplex-polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) procedure for simultaneous genotyping of cytochrome P450 II E1 (CYP2E1), microsomal epoxide hydrolase (mEH), and glutathione S-transferase mu (GSTM1). Enzymes from these three polymorphic genes are involved with the phase I and II metabolism of a variety of environmental toxicants. Therefore, simultaneous characterization of these genes will not only reduce costs but will increase the efficiency of data collection, thereby contributing to health risk assessment efforts.

Unilateral renal cystic disease in adults

Unilateral renal cystic disease (URCD) is morphologically indistinguishable from autosomal dominant polycystic kidney disease (ADPKD) except for its unilaterality. Unlike ADPKD, URCD patients show neither a genetic background nor progressive deterioration in renal function; thus, the differential diagnosis of URCD from ADPKD is important. Only a few cases of URCD have been reported. This study reports two cases of URCD in adults together with a literature review. We identified these two cases using abdominal computerized tomography and family screening with renal ultrasonography.

The effect of continuous ambulatory peritoneal dialysis on change in serum leptin

OBJECTIVE

Elevated serum leptin can contribute to anorexia and poor nutrition in patients with chronic renal failure, because leptin is elevated in chronic renal failure patients with or without dialysis, especially in chronic ambulatory peritoneal dialysis (CAPD) patients. The aim of this study was to find whether leptin can be removed by peritoneal dialysis (PD) and to analyze factors that can affect serum leptin after start of CAPD by observing the change in serum leptin shortly after start of CAPD and its correlation with body mass index (BMI), with serum insulin, and with residual renal function.

DESIGN

Twenty patients who started CAPD during the observation period were studied. Serum leptin was measured by radioimmunoassay before start of CAPD, 3-5 days after start of CAPD, and 1 month and 3 months after start of CAPD. Simultaneously, body weight, serum insulin, and residual renal function were measured. To compensate for the circardian rhythm of leptin, removal of leptin was assessed by measuring dialysate leptin divided by average serum leptin before and after a peritoneal equilibration test (PET).

RESULTS

Leptin was eliminated by PD with a dialysate-to-serum ratio of 0.16+/-0.07, which was comparable to removal of beta2-microglobulin (0.14+/-0.06). The mean serum leptin concentrations did not decrease after 3-5 days of CAPD (8.4+/-13.1 ng/mL-->11.9+/-18.0 ng/mL) despite its removal by PD, and levels increased markedly to 189% of basal serum leptin 1 month after start of PD and to 260% of basal serum leptin 3 months after start of PD. Correlation coefficients (Spearman's rho) between change of serum leptin and change of BMI, of serum insulin, of glomerular filtration rate (average of urine creatinine clearance and urine urea clearance) were 0.267 (p > 0.05, n = 20), 0.441 (p > 0.05, n = 16), 0.706 (p > 0.05, n = 8) respectively.

CONCLUSION

Leptin is removed by peritoneal dialysis. Serum leptin did not decrease in 5 days after the start of PD despite its removal by PD, but increased markedly thereafter, within 3 months after start of PD. We could not find a significant correlation between the change in leptin and the change in BMI. Factors other than fat-mass gain can stimulate leptin increase shortly after start of PD.

The effect of dialysate dwell on gastric emptying time in patients on continuous ambulatory peritoneal dialysis

METHODS AND PATIENTS

We evaluated gastric emptying time (GET) with a technetium (Tc) 99m-sulfur colloid gastric emptying scan in 11 patients on continuous ambulatory peritoneal dialysis (CAPD) (6 males, 5 females) and in 14 controls. We investigated the effect of dialysate dwell on GET by studying the subjects twice: once without dialysate in the abdomen (drained) and once with 2 L of dialysate in the abdomen (full). We also investigated the relationship between body surface area (BSA) and delayed gastric emptying.

RESULTS

(1) The mean gastric emptying rate in 120 minutes in patients on CAPD when drained (67.8%+/-13.4%) was not different from that in controls (65.4%+/-8.6%). (2) The mean gastric emptying rate in 120 minutes in patients on CAPD when full was significantly slower than that when drained (55.6%+/-14.6% versus 67.8%+/-13.4%, p < 0.05). In four of the 11 patients (36.4%), gastric emptying was extremely delayed from normal to abnormal range when full. (3) The BSA of patients who had extremely delayed GET from normal to abnormal range was smaller than that of patients who had minimal delayed or unchanged GET when full (1.5+/-0.11 m2 versus 1.74+/-0.22 m2).

CONCLUSION

This study showed that patients on CAPD had normal gastric emptying when drained, and that gastric emptying was delayed by dialysate dwell, especially in patients who has less than 1.5 m2 of body surface area. Therefore, we suggest that, based on adequacy, intermittent nocturnal peritoneal dialysis or a small volume of dialysate be considered for patients with small body surface area.

Farnesylcysteine methyltransferase activity and Ras protein expression in human stomach tumor tissue

The processing pathway of G-proteins and Ras family proteins includes the isoprenylation of the cysteine residue, followed by proteolysis of three terminal residues and alpha-carboxyl methyl esterification of the cysteine residue. Farnesylcysteine methyltransferase (FCMT) activity is responsible for the methylation reaction which play a role in the membrane attachment of a variety of cellular proteins. Four kinds of Ras protein (c-Ha-ras, c-N-Ras, c-Ki-Ras, pan-Ras) expression were detected in adenocarcinoma of human tissue by immunohistochemical method, and hematoxylin and eosin staining. The level of Ras protein in human stomach tumor tissues was much higher than in normal and peritumoral regions of the same biopsy samples. The FCMT activities of each cellular fractions were high in mitochondrial fraction followed by microsomal fraction, whole homogenate and cytosolic fraction. The inhibitory effect on FCMT activity on stomach tumor tissue was determined after treatment with 0.25 microM of S-adenosyl-L-homocysteine. S-adenosyl-L-homocysteine inhibited FCMT activity from 11.2% to 30.5%. These results suggested that FCMT might be involved in Ras proteins activity.

Elevation of cytosolic calcium of rat cardiac myocytes in phosphate depletion

Phosphate depletion is associated with a rise in cytosolic calcium ([Ca2+]i) of cells and such a derangement is responsible in major part for organ dysfunction in phosphate depletion (PD). Cardiac function is impaired in PD, and it is possible that PD is also associated with rise in [Ca2+]i of cardiac myocytes. The present study examined the effect of PD on [Ca2+]i of cardiac myocytes and explored the mechanisms that may lead to the rise in their [Ca2+]i. The [Ca2+]i of cardiac myocytes began to rise and ATP content began to fall at the third week of PD. After six weeks of PD, the values of [Ca2+]i were significantly higher (P < 0.01) and those of ATP content were significantly lower (P < 0.01) than in control (PW) rats. The Vmax of Ca2(+)-ATPase and Na+,K(+)-ATPase as well as the Na(+)-Ca2+ exchange were significantly lower (P < 0.01) in PD than in PW animals. The data of the present study are consistent with the notion that the rise in [Ca2+]i of cardiac myocytes of PD rats is due to a decrease in calcium efflux out of them.

Phosphate depletion impairs leucine-induced insulin secretion

Phosphate depletion (PD) in vivo causes a sundry of abnormalities in pancreatic islets including a rise in cytosolic calcium, low ATP content, reduced Ca2+ ATPase and Na(+)-K+ ATPase activity, and impaired insulin secretion in response to glucose or potassium. L-Leucine is a strong secretagogue that triggers insulin secretion by deamination to alpha-ketoisocaproic acid (KIC) and the subsequent metabolism of the latter to ATP and by the activation of glutamate dehydrogenase (GLDH), which acts on glutamate to generate alpha-ketoglutarate, the metabolism of which results in ATP production. The generation of ATP triggers events that lead to insulin secretion. It is not known whether PD impairs leucine-induced insulin secretion, and the cellular derangements that are involved in such an abnormality are not defined. These issues were studied in PD rats and in pair-weighed normal animals as controls. D-Leucine uptake by islets from PD rats is normal, but both leucine- and KIC-induced insulin secretions are impaired and the activity of branched-chain keto acid dehydrogenase, which facilitates the metabolism of KIC, is reduced. Both leucine and 2-aminobicyclo (2-2-1) haptene failed to stimulate GLDH and to augment the generation of alpha-ketoglutarate in the islets of PD rats. Also, the concentration of basal alpha-ketoglutarate was significantly higher in the islets of PD rats, suggesting that its metabolism is impaired. In addition, the activity of glutaminase is significantly reduced, an abnormality that would result in decreased production of glutamate, the substrate for GLDH. The data show that PD impairs leucine-induced insulin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormal leucine-induced insulin secretion in chronic renal failure

Chronic renal failure (CRF) is associated with a sundry of abnormalities in pancreatic islets including a rise in their cytosolic calcium, reduced ATP content, and impaired glucose-induced insulin secretion. The latter is also stimulated by amino acids (such as leucine), and the cellular processes involved in leucine-induced insulin secretion are different from those responsible for glucose-induced insulin release. The present study examined whether leucine-induced insulin secretion is also impaired in CRF and investigated the cellular derangements for such a potential abnormality. The results showed that leucine-induced insulin secretion is markedly reduced by islets from CRF animals, and this defect was prevented by parathyroidectomy (PTX) of the CRF animals or by their treatment with verapamil, an agent that blocks the action of parathyroid hormone (PTH) on the pancreatic islets. Both leucine uptake and alpha-ketoisocaproic acid-induced insulin secretion by islets from CRF rats are normal; however, both the activation of glutamate dehydrogenase (GLDH) by leucine or by 2-aminobicyclo-[2-2-1]-haptene and the utilization of alpha-ketoglutarate are impaired, and the maximal reaction rate (Vmax) of glutaminase is reduced. These derangements are corrected by PTX of CRF rats or by their treatment with verapamil. The data demonstrate that 1) CRF is associated with impaired leucine-induced insulin secretion, 2) this defect is due to the state of secondary hyperparathyroidism of CRF, and 3) the cellular derangements responsible for this defect involve abnormalities in the metabolism of leucine and derangements in the leucine-GLDH-alpha-ketoglutarate-glutaminase pathway of the islets.

Verapamil prevents chronic renal failure-induced abnormalities in lipid metabolism

Hypertriglyceridemia is common in chronic renal failure (CRF); this derangement is due to decreased peripheral removal of triglycerides. Certain data indicate that the state of secondary hyperparathyroidism of CRF is, at least in part, responsible for derangements in lipid metabolism. It has been proposed that chronic excess of parathyroid hormone exerts its deleterious effects on many organs through its ability to raise basal levels of cytosolic calcium. Prevention of the latter by a calcium channel blocker is followed by the correction of organ dysfunctions. The present study examined the effect of treatment of CRF rats with verapamil on several parameters of lipid metabolism. Chronic renal failure rats displayed hypertriglyceridemia, fat intolerance, reduced postheparin plasma lipoprotein and hepatic lipase activities, decreased hepatic lipase in liver homogenate, and elevated calcium content in liver and epididymal fat. Treatment of the CRF rats with verapamil prevented all these derangements in lipid metabolism. These effects of verapamil were similar to those produced by parathyroidectomy of CRF rats. The data are consistent with the formulation that chronic excess of parathyroid hormone increases the calcium burden of liver and adipose tissue and consequently impairs the synthesis and/or release of lipoprotein and hepatic lipases. Reduced availability of these enzymes in plasma results in impared peripheral removal of triglycerides, leading to hypertriglyceridemia.

Abnormalities of glomerular basement membrane in acute postinfectious glomerulonephritis

The segmental abnormalities of glomerular basement membrane (GBM) were studied by electron microscopy in 69 renal biopsies with acute postinfectious glomerulonephritis (APGN) and correlated with the general morphologic features and clinical findings. Thirty-six were children and 33 were adults. Biopsies were grouped into three stages by light microscopy: exudative stage (25 patients), exudative-proliferative stage (26) and proliferative stage (18). Subepithelial deposits or "humps" were present in 59 patients (86%). The frequency of humps was significantly lower at the proliferative stage than that noted in the earlier biopsies (p less than 0.01). Intramembranous, subendothelial and mesangial deposits were shown in 83% to 88% of the patients. The overall frequency of GBM abnormalities was 45%, showing significantly higher frequency in children than in adults (p less than 0.01). Dissolving subepithelial deposits were often present in the foci with GBM abnormalities. The GBM lesions were not related to more severe clinical manifestations or outcomes, but tended to occur more frequently in later biopsies (p less than 0.01). These results suggest that abnormalities of GBM in APGN are more often present than formerly assumed, especially in children, and could be a normal response to subepithelial deposits. The occurrence of these lesions in other types of immune-related glomerulonephritis may be considered along the same lines.