Clinical analysis of living related renal transplantation with donors older than 50 years in China

OBJECTIVE

The objective of this study was to investigate whether kidney grafts from living related donors older than 50 years were safe for the donors and recipients in the long term.

METHODS

One hundred seven living related donor kidney transplantations were performed in our center from April 1994 to December 2007. No prisoners or organs from prisoners were used in the collection of these data. Donors were divided into 2 groups: >50 years of age (range, 51-78 years), designated as the study group, and ≤50 years of age (range, 21-50 years), designated as the control groups. The mean time of follow-up was 49 months (range, 12-180 months). Clinical data were compared, including donor serum creatinine (Scr) levels, glomerular filtration rates (GFR) before and after the procedures operative complications, and postoperative short-term and long-term recovery of renal function in recipients as well as their complications and recipient and kidney survivals.

RESULTS

All operations were successfully performed. Before the operation, the mean Scr and GFR were 82.16 ± 10.86 umol/L and 85.82 ± 6.26 mL/min, respectively, in the study group versus 78.66 ± 10.41 umol/L and 88.74 ± 9.44 mL/min, respectively, in the control group. There were no significant differences in mean Scr or GFR values between the groups at various preoperative or postoperative times (P > .05). No severe perioperative complications occurred, and no subsequent renal function failure was observed upon long-term follow-up of donors in the 2 groups. Comparisons of recipient age, gender ratio, duration on dialysis, HLA matches, cold/warm ischemia times, and immunosuppression therapy showed a correlations between the 2 groups. Mean Scr levels of recipients, which were compared from 1 week to 3 years following surgery, were slightly higher among the control than the study group, but the difference was not significant (P > .05). There were no significant differences between the study and control groups in 1-,3-,5-, and 8-year recipient/graft survival rates (P > .05).

CONCLUSIONS

Long-term follow-up showed that transplantations using grafts from donors older than 50 years of age yielded similar results to those with younger donors.

Metabolic regulation of lrp gene expression in Escherichia coli K-12

Expression of the lrp gene is regulated in part by the nutrients available to the cell, and is decreased in rich medium, in glucose minimal media enriched with amino acids, and in minimal medium with alternative carbon sources, such as acetate and succinate. When Lrp production is increased in a given medium, expression of its target genes is also increased. However, when the medium is changed from glucose to acetate, the response of the target genes is governed by many factors.

Characterization of the expression of the thcB gene, coding for a pesticide-degrading cytochrome P-450 in Rhodococcus strains

A cytochrome P-450 system in Rhodococcus strains, encoded by thcB, thcC, and thcD, participates in the degradation of thiocarbamates and several other pesticides. The regulation of the system was investigated by fusing a truncated lacZ in frame to thcB, the structural gene for the cytochrome P-450 monooxygenase. Analysis of the thcB-lacZ fusion showed that the expression of thcB was 10-fold higher in the presence of the herbicide EPTC (s-ethyl dipropylthiocarbamate). Similar enhancement of the thcB-lacZ expression was found with other thiocarbamate pesticides. Atrazine, simazine, or carbofuran, although metabolized by the system, had no effect on the thcB-lacZ expression. The presence of glucose slightly increased the expression of thcB-lacZ, indicating no catabolic repression of the thcB-lacZ expression. The expression of thcB-lacZ was decreased more than twofold in Luria-Bertani medium. This was due in part to cysteine, which repressed thcB-lacZ expression. It was confirmed that the thcR gene, which is transcribed divergently from thcB, codes for a positive regulatory protein which is essential for the thcB-lacZ expression. Studies of the thcR-lacZ protein fusion showed that the thcR gene is expressed constitutively.

Cloning and expression of the s-triazine hydrolase gene (trzA) from Rhodococcus corallinus and development of Rhodococcus recombinant strains capable of dealkylating and dechlorinating the herbicide atrazine

We used degenerate oligodeoxyribonucleotides derived from the N-terminal sequence of the s-triazine hydrolase from Rhodococcus corallinus NRRL B-15444R in an amplification reaction to isolate a DNA segment containing a 57-bp fragment from the trzA gene. By using the nucleotide sequence of this fragment, a nondegenerate oligodeoxyribonucleotide was synthesized and used to screen a genomic library of R. corallinus DNA for fragments containing trzA. A 5.3-kb PstI fragment containing trzA was cloned, and the nucleotide sequence of a 2,450-bp region containing trzA was determined. No trzA expression was detected in Escherichia coli or several other gram-negative bacteria. The trzA gene was subcloned into a Rhodococcus-E. coli shuttle vector, pBS305, and transformed into several Rhodococcus strains. Expression of trzA was demonstrated in all Rhodococcus transformants. Rhodococcus sp. strain TE1, which possesses the catabolic gene (atrA) for the N-dealkylation of the herbicides atrazine and simazine, was able to dechlorinate the dealkylated metabolites of atrazine and simazine when carrying the trzA gene on a plasmid. A plasmid carrying both atrA and trzA was constructed and transformed into three atrA- and trzA-deficient Rhodococcus strains. Both genes were expressed in the transformants. The s-triazine hydrolase activity of the recombinant strains carrying the trzA plasmid were compared with that of the R. corallinus strain from which it was derived.

Cloning of the genes for degradation of the herbicides EPTC (S-ethyl dipropylthiocarbamate) and atrazine from Rhodococcus sp. strain TE1

The degradation of the herbicides EPTC (S-ethyl dipropylthiocarbamate) and atrazine (2-chloro-4-ethyl-amino-6-isopropylamino-1,3,5-triazine) is associated with an indigenous plasmid in Rhodococcus sp. strain TE1. Plasmid DNA libraries of Rhodococcus sp. strain TE1 were constructed in a Rhodococcus-Escherichia coli shuttle vector, pBS305, and transferred into Rhodococcus sp. strain TE3, a derivative of Rhodococcus sp. strain TE1 lacking herbicide degradation activity, to select transformants capable of growing on EPTC as the sole source of carbon (EPTC+). Analysis of plasmids from the EPTC+ transformants indicated that the eptA gene, which codes for the enzyme required for EPTC degradation, residues on a 6.2-kb KpnI fragment. The cloned fragment also harbored the gene required for atrazine N dealkylation (atrA). The plasmid carrying the cloned fragment could be electroporated into a number of other Rhodococcus strains in which both eptA and atrA were fully expressed. No expression of the cloned genes was evident in E. coli strains. Subcloning of the 6.2-kb fragment to distinguish between EPTC- and atrazine-degrading genes was not successful.