A comparative study of psychosocial determinants and mental well-being in chronic kidney disease patients: A closer look.

BACKGROUND: Depressive illness in chronic kidney disease (CKD) is an independent risk factor for morbidity and mortality. The relation between depressive illness and quality of life (QoL) in this vulnerable group is complex. We attempted to study the burden of depressive illness, the QoL in patients of CKD on hemodialysis (HD), and peritoneal dialysis (PD) as well as those who were not on any dialysis but on conservative medical management only. MATERIALS AND METHODS: Observational study with cross-sectional analytical controlled design. STATISTICAL METHODS USED: Chi-square statistic or Fisher's exact test for categorical variables and t-test and ANOVA for continuous variables. Correlational analysis was done using Spearman's correlation coefficient. P <0.05 was considered as statistically significant. RESULTS: Depressive symptoms were present significantly across all 3 groups of CKD patients. Depressive disorder was significantly higher in the HD group. Mean QoL was significantly better in patients of CKD on PD. DISCUSSION: There is huge hidden burden of depressive symptoms and depressive illness in patients of CKD whether on dialysis or on conservative medical management. The study found significantly higher burden of depressive illness and lower QoL among the HD vis a vis PD patients, even though the majority of our CKD who require dialysis are on HD. CONCLUSION: Depressive burden is the hidden factor behind poor QoL, poor overall satisfaction as well as treatment outcome in patients of CKD whether or not on dialysis. To address this hidden depressive burden comprehensively, close cooperation between nephrologist and psychiatrist is called for.

Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

INTRODUCTION: As there is a paucity of literature regarding the long-term outcomes of complex living donors, we conducted this study to assess the effect of kidney donation on the complex living kidney donor. MATERIALS AND METHODS: This retrospective study was conducted in Narayan Health Hospital, Kolkata, Eastern India. The cohort consisted of complex living kidney donors who donated kidneys between the years 2007 and 2012. All donors were 60 years old or older, or were younger than 60 years and had comorbidities like hypertension and obesity. After a minimum follow-up of 5 years, all donors underwent evaluation. Data pertaining to hypertension, new-onset diabetes, body mass index (BMI), estimated glomerular filtration rate (eGFR) and albuminuria, and cardiac events were compared from the time of donation till 5 years post-transplant. RESULTS AND DISCUSSION: We found a statistically significant increase in blood pressure, number of antihypertensives used, and mean BMI at follow-up. Diabetes mellitus was developed in 22.3% of donors. The mean GFR also decreased significantly at follow-up. There were 42 elderly donors (≥60 years) and 23 ≤ 59 years of age. There was a significant fall of eGFR in both groups, but the percentage fall was similar in both groups. A significant percentage of donors developed proteinuria, the majority being hypertensives. CONCLUSION: Procurement of kidneys from marginal donors should be done cautiously, and donors should be assessed for morbidity and mortality in the future, as we found a statistically significant deterioration in renal function, blood pressure, and BMI over long-term follow-up.

Outcome of ABO-Incompatible Living Donor Renal Transplantations: A Single-Center Experience From Eastern India.

BACKGROUND: With the incessantly increasing number of patients on the waiting list for renal transplants, crossing the blood group barrier can substantially increase the donor pool. We started ABO-incompatible (ABOi) renal transplantation in 2013 with a relatively low-cost preconditioning protocol (additional cost, ∼$1200). This study reports the short-term outcome of ABOi renal transplantations performed at our institution. METHODS: A total of 45 adult ABOi kidney transplant recipients (KTRs) were included in the study. All of them underwent a pretransplantation conditioning program, which included plasmapheresis, low-dose intravenous immunoglobulin (IVIG), and low-dose rituximab. A pretransplantation isoagglutinin titer of ≤1:8 was considered acceptable for transplantation until December 2014, after which the threshold was increased to ≤1:32. RESULTS: Overall, 50% of KTRs were of blood group O. The maximum initial antibody titer was 1:2048. All the patients achieved immediate graft function post-transplantation. The mean serum creatinine level at 370 days (median duration of follow-up) was 1.21 mg%. One graft was lost due to severe antibody-mediated rejection (ABMR) with cortical necrosis. The graft survival rate was 97.78% and the patient survival rate was 97.78%. The overall result in terms of graft and patient survival, infections, and rejections were similar to ABO-compatible transplantations. CONCLUSIONS: ABOi renal transplantation is a cost-effective modality to increase the donor pool. Contrary to the belief that this modality is extremely expensive and requires elaborate infrastructure, we had a good short-term outcome with a relatively simple and low-cost preconditioning protocol.

Estimation of the rate of tooth wear in permanent incisors: a cross-sectional digital radiographic study.

This study used conventional digital radiography to estimate the rate of tooth wear (TW) of maxillary and mandibular central incisors based on a cross-sectional study design. The crown length of 1239 permanent maxillary and mandibular central incisors from 346 persons (age groups: 10, 25, 40, 55 and 70 years ± 3) were measured by three calibrated dentists. Study teeth were intact incisally, had clearly visible incisal edges and cementoenamel junctions and had natural tooth antagonists. Measures were based on digital radiographic images (N = 666) archived in MiPACS within the electronic health record (axiUm(®)) from the College of Dentistry patient database. Incisor crown length decreased at a linear rate in both arches over the 60 years represented by the age groups. The average crown length for maxillary incisors in the youngest age group was 11.94 mm, which decreased by an average of 1.01 mm by median age 70. For mandibular incisors, the average crown length in the youngest age group was 9.58 mm, which decreased by an average of 1.46 mm in the oldest age group. Males and females showed similar rates of TW. Regardless of age, females demonstrated smaller mean crown height for maxillary incisors than males (P < 0.0001). Measures by the examiners demonstrated good agreement, with an interclass correlation coefficient of 0.869 and an average intra-examiner correlation of 99.5%, based on repeated measurements (n = 100). TW was estimated to average 1.01 mm for maxillary central incisors and 1.46 mm for mandibular central incisors by age 70 years.

Instability and pattern formation in reaction-diffusion systems: a higher order analysis.

We analyze the condition for instability and pattern formation in reaction-diffusion systems beyond the usual linear regime. The approach is based on taking into account perturbations of higher orders. Our analysis reveals that nonlinearity present in the system can be instrumental in determining the stability of a system, even to the extent of destabilizing one in a linearly stable parameter regime. The analysis is also successful to account for the observed effect of additive noise in modifying the instability threshold of a system. The analytical study is corroborated by numerical simulation in a standard reaction-diffusion system.

Disruption of the Crithidia fasciculata KAP1 gene results in structural rearrangement of the kinetoplast disc.

The mitochondrial DNA (kinetoplast DNA) in trypanosomatids exists as a highly organized nucleoprotein structure with the DNA consisting of thousands of interlocked circles. Four H1 histone-like proteins (KAP1, 2, 3 and 4) are associated with the kinetoplast DNA in the trypanosomatid Crithidia fasciculata. We have disrupted both alleles of the KAP1 gene in this diploid protozoan and shown that expression of the KAP1 protein is eliminated. The mutant strain is viable but has substantial rearrangement of the kinetoplast structure. Expression of the KAP1 protein from an episome restored expression of the KAP1 protein in the mutant strain and also restored a normal kinetoplast structure. These studies provide evidence that the KAP1 protein is involved in kinetoplast DNA organization in vivo but is nonessential for cell viability.

Noise properties of stochastic processes and entropy production.

Based on a Fokker-Planck description of external Ornstein-Uhlenbeck noise and cross-correlated noise processes driving a dynamical system we examine the interplay of the properties of noise processes and the dissipative characteristic of the dynamical system in the steady state entropy production and flux. Our analysis is illustrated with appropriate examples.

Analytical and numerical investigation of escape rate for a noise driven bath.

We consider a system-reservoir model where the reservoir is modulated by an external noise. Both the internal noise of the reservoir and the external noise are stationary, Gaussian, and are characterized by arbitrary decaying correlation functions. Based on a relation between the dissipation of the system and the response function of the reservoir driven by external noise, we numerically examine the model using a full bistable potential to show that one can recover the turn-over features of the usual Kramers' dynamics when the external noise modulates the reservoir rather than the system directly. We derive the generalized Kramers' rate for this nonequilibrium open system. The theoretical results are verified by numerical simulation.

Characterization of the Crithidia fasciculata mRNA cycling sequence binding proteins.

The Crithidia fasciculata cycling sequence binding protein (CSBP) binds with high specificity to sequence elements in several mRNAs that accumulate periodically during the cell cycle. Mutations in these sequence elements abolish both cycling of the mRNA and binding of CSBP. Two genes, CSBPA and CSBPB, encoding putative subunits of CSBP have been cloned and were found to be present in tandem on the same DNA molecule and to be closely related. CSBPA and CSBPB are predicted to encode proteins with sizes of 35.6 and 42.0 kDa, respectively. Both CSBPA and CSBPB proteins have a predicted coiled-coil domain near the N terminus and a novel histidine and cysteine motif near the C terminus. The latter motif is conserved in other trypanosomatid species. Gel sieving chromatography and glycerol gradient sedimentation results indicate that CSBP has a molecular mass in excess of 200 kDa and an extended structure. Recombinant CSBPA and CSBPB also bind specifically to the cycling sequence and together can be reconstituted to give an RNA gel shift similar to that of purified CSBP. Proteins in cell extracts bind to an RNA probe containing six copies of the cycling sequence. The RNA-protein complexes contain both CSBPA and CSBPB, and the binding activity cycles in near synchrony with target mRNA levels. CSBPA and CSBPB mRNA and protein levels show little variation throughout the cell cycle, suggesting that additional factors are involved in the cyclic binding to the cycling sequence elements.

RNA primer removal and gap filling on a model minicircle replication intermediate.

Replication of kinetoplast DNA minicircles in Crithidia fasciculata occurs by a unidirectional mechanism involving continuous synthesis of one strand (L strand) and discontinuous synthesis of the complementary strand (H strand). L-strands are initiated by RNA priming at alternate origins (A and B) resulting in daughter molecules with a single nick or gap in the L strand at either ori A or ori B. Some of the gapped molecules contain ribonucleotides at the 5' side of the gap. We have investigated the ability of recombinant forms of kinetoplast replication proteins, DNA polymerase beta and structure specific endonuclease 1, to repair gaps in a model minicircle substrate. Structure specific endonuclease 1 was shown to efficiently remove all ribonucleotides from the 5' side of the model substrate by stepwise cleavage of the RNA primer. Polymerase beta was then able to extend the 3' terminus of the gap to yield a nicked molecule capable of covalent joining by a DNA ligase. These results demonstrate that the nuclease and polymerase enzymes present at antipodal protein complexes flanking the kinetoplast disk are capable of complete RNA primer removal and subsequent gap filling of newly synthesized minicircle L strands.

The Crithidia fasciculata RNH1 gene encodes both nuclear and mitochondrial isoforms of RNase H.

The Crithidia fasciculata RNH1 gene encodes an RNase H, an enzyme that specifically degrades the RNA strand of RNA-DNA hybrids. The RNH1 gene is contained within an open reading frame (ORF) predicted to encode a protein of 53.7 kDa. Previous work has shown that RNH1 expresses two proteins: a 38 kDa protein and a 45 kDa protein which is enriched in kinetoplast extracts. Epitope tagging of the C-terminus of the RNH1 gene results in localization of the protein to both the kinetoplast and the nucleus. Translation of the ORF beginning at the second in-frame methionine codon predicts a protein of 38 kDa. Insertion of two tandem stop codons between the first ATG codon and the second in-frame ATG codon of the ORF results in expression of only the 38 kDa protein and the protein localizes specifically to the nucleus. Mutation of the second methionine codon to a valine codon prevents expression of the 38 kDa protein and results in exclusive production of the 45 kDa protein and localization of the protein only in the kinetoplast. These results suggest that the kinetoplast enzyme results from processing of the full-length 53.7 kDa protein. The nuclear enzyme appears to result from translation initiation at the second in-frame ATG codon. This is the first example in trypanosomatids of the production of nuclear and mitochondrial isoforms of a protein from a single gene and is the only eukaryotic gene in the RNase HI gene family shown to encode a mitochondrial RNase H.

Identification of cis and trans elements involved in the cell cycle regulation of multiple genes in Crithidia fasciculata.

Transcripts of several DNA replication genes, including the RPA1 and TOP2 genes, encoding the large subunit of nuclear replication protein A and the kinetoplast topoisomerase II, accumulate periodically during the cell cycle in the trypanosomatid Crithidia fasciculata. An octamer consensus sequence, CAUAGAAG, present in the 5' untranslated regions (UTR) of these mRNAs is required for periodic accumulation of the TOP2 and RPA1 transcripts and also for binding of a nuclear factor(s) to the 5' UTR RNAs of these genes. We show here that insertion of multiple (six) copies of this octamer sequence (6x octamer) into the 5' UTR of a reporter gene confers periodic accumulation on its transcript. Competition experiments and UV cross-linking studies show that the 6x octamer RNA and TOP2 5' UTR RNA bind to the same nuclear factor(s). Single-nucleotide substitutions in the 6x octamer that abolish the RNA gel shift also prevent cyclic accumulation of the reporter gene transcript. A protein termed cycling element binding protein, purified by affinity chromatography using 6x octamer RNA as a ligand, binds to RNAs containing wild-type octamers and not to those with mutant octamers. These results define a small sequence element in C. fasciculata mRNAs required for their cell cycle regulation and report the identification and purification of a putative regulatory protein that binds specifically to these elements.

The kinetoplast structure-specific endonuclease I is related to the 5' exo/endonuclease domain of bacterial DNA polymerase I and colocalizes with the kinetoplast topoisomerase II and DNA polymerase beta during replication.

The mitochondrial DNA (kinetoplast DNA) of the trypanosomatid Crithidia fasciculata has an unusual structure composed of minicircles and maxicircles topologically interlocked into a single network and organized in a disc-shaped structure at the base of the flagellum. We previously purified a structure-specific endonuclease (SSE1), based on its RNase H activity, that is enriched in isolated kinetoplasts. The endonuclease gene has now been cloned, sequenced, and found to be closely related to the 5' exonuclease domain of bacterial DNA polymerase I proteins. Although the protein does not contain a typical mitochondrial leader sequence, the enzyme is shown to colocalize with a type II DNA topoisomerase and a DNA polymerase beta at antipodal sites flanking the kinetoplast disc. Cell synchronization studies with an epitope-tagged construct show that the localization of the endonuclease to the antipodal sites varies in a cell cycle-dependent manner similar to that of the DNA polymerase beta [Johnson, C. E. & Englund, P. T. (1998) J. Cell Biol. 143, 911-919]. Immunofluorescent localization of SSE1 to the antipodal sites is only observed during kinetoplast replication. Together, these results suggest a point of control for kinetoplast DNA replication through the regulation of the availability of DNA replication proteins and a possible role for the antipodal sites in removal of RNA primers and the repair of gaps in newly replicated minicircles.

A structure-specific DNA endonuclease is enriched in kinetoplasts purified from Crithidia fasciculata.

The mitochondrial DNA (kinetoplast DNA) of the trypanosomatid Crithidia fasciculata consists of minicircles and maxicircles topologically interlocked in a single network per cell. Individual minicircles replicate unidirectionally from either of two replication origins located 180 degrees apart on the minicircle DNA. Initiation of minicircle leading-strand synthesis involves the synthesis of an RNA primer which is removed in the last stage of replication. We report here the purification to near homogeneity of a structure-specific DNA endo-nuclease based on the RNase H activity of the enzyme on a poly(rA).poly(dT) substrate. RNase H activity gel analysis of whole cell and kinetoplast extracts shows that the enzyme is enriched in kinetoplast fractions. The DNA endonuclease activity of the enzyme is specific for DNA primers annealed to a template strand and requires an unannealed 5' tail. The enzyme cleaves 3' of the first base paired nucleotide releasing the intact tail. The purified enzyme migrates as a 32 kDa protein on SDS gels and has a Stoke's radius of 21.5 A and a sedimentation coefficient of 3.7 s, indicating that the protein is a monomer in solution with a native molecular mass of 32.4 kDa. These results suggest that the enzyme may be involved in RNA primer removal during minicircle replication.

Nuleclear extracts of Crithidia fasciculata contain a factor(s) that binds to the 5'-untranslated regions of TOP2 and RPA1 mRNAs containing sequences required for their cell cycle regulation.

The Crithidia fasciculata replication protein A gene, RPA1, and topoisomerase II gene, TOP2, encode proteins involved in the replication of nuclear and mitochondrial DNA, respectively. Transcripts of both genes accumulate periodically during the cell cycle and attain their maximum levels just before S phase. Octamer consensus sequences within the 5'-untranslated region (UTR) of both genes have been shown to be necessary for cycling of these transcripts. Using a gel retardation assay, we show here that nuclear extracts of C. fasciculata contain a protein factor(s) that binds specifically to RNA from 5'-UTRs of TOP2 and RPA1 genes. In addition, mutations in the consensus octamer sequence abolish binding to the RNA in both cases. Ultraviolet cross-linking using a radiolabeled TOP2 5'-UTR probe identified proteins with apparent molecular masses of 74 and 37 kDa in the RNA-protein complex. Nuclear extracts prepared from synchronized cells show that the binding activity varies during the cell cycle in parallel with TOP2 and RPA1 mRNA levels. These results suggest that the cell cycle regulation of the mRNA levels of trypanosomatid DNA replication genes may be mediated by binding of specific proteins to conserved sequences in the 5'-UTR of their transcripts.

The Crithidia fasciculata KAP1 gene encodes a highly basic protein associated with kinetoplast DNA.

The Crithidia fasciculata KAP1 gene encodes a small basic protein (p21) associated with kinetoplast DNA. The p21 protein has a nine amino acid cleavable presequence closely related to those of several other proteins targeted to the kinetoplast and binds non-specifically to kinetoplast minicircle DNA. The p21 protein also has a calculated pI of 13 with two amino acids (lysine and alanine) accounting for more than 50% of the residues and with 25 out of 28 lysine residues contained in the C-terminal half of the protein. Immunolocalization of p21 shows that the protein is found exclusively in the kinetoplast with a localization distinctly different from the antipodal localization of kinetoplast DNA topoisomerase and DNA polymerase. The KAP11 gene is a single copy gene and the KAP1 mRNA is present at a constant level throughout the cell cycle. This highly basic protein may play a role in the condensation or segregation of the kinetoplast DNA.

Tandem arrangement of two genes encoding kinetoplast-associated H1 histone-like proteins.

Crithidia fasciculata proteins p18 and p17 are associated with kinetoplast DNA and are encoded by genes KAP2 and KAP3, respectively. Polymerase chain reaction (PCR) amplification using primers within the coding sequences of each gene revealed that the KAP2 and KAP3 genes are linked on the same chromosomal DNA and are separated by a 1.8 kb intergenic region containing several long homopolymer tracts. The KAP2 gene has a 3'UTR of more than 1.1 kb or almost three times as long as the KAP2 coding sequence. Several restriction enzyme polymorphisms in this region of the chromosome are the result of sequence differences between the two alleles of the KAP2 gene. The predicted amino-acid sequences of alleles KAP2-1 and KAP2-2 differ by three non-conservative amino acid substitutions in the highly basic carboxyl tail of the protein and suggest that the protein products could have different physical and biological properties. The KAP2 and KAP3 genes have different patterns of mRNA expression during the cell cycle with the KAP3 transcript varying periodically during the cell cycle in the same manner as transcripts of several kinetoplast and nuclear DNA replication genes.