A Cost-Benefit Analysis of Government Compensation of Kidney Donors.

From 5000 to 10 000 kidney patients die prematurely in the United States each year, and about 100 000 more suffer the debilitating effects of dialysis, because of a shortage of transplant kidneys. To reduce this shortage, many advocate having the government compensate kidney donors. This paper presents a comprehensive cost-benefit analysis of such a change. It considers not only the substantial savings to society because kidney recipients would no longer need expensive dialysis treatments--$1.45 million per kidney recipient--but also estimates the monetary value of the longer and healthier lives that kidney recipients enjoy--about $1.3 million per recipient. These numbers dwarf the proposed $45 000-per-kidney compensation that might be needed to end the kidney shortage and eliminate the kidney transplant waiting list. From the viewpoint of society, the net benefit from saving thousands of lives each year and reducing the suffering of 100 000 more receiving dialysis would be about $46 billion per year, with the benefits exceeding the costs by a factor of 3. In addition, it would save taxpayers about $12 billion each year.

Discovery and quantification of a widespread methane ebullition event in a coastal inlet (Baltic Sea) using a novel sonar strategy.

How much of the greenhouse gas methane is transported from the seafloor to the atmosphere is unclear. Here, we present data describing an extensive ebullition event that occurred in Eckernförde Bay, a shallow gas-hosting coastal inlet in the Baltic Sea, in the fall of 2014. A weak storm induced hydrostatic pressure fluctuations that in turn stimulated gas ebullition from the seabed. In a finely tuned sonar survey of the bay, we obtained a hydroacoustic dataset with exceptionally high sensitivity for bubble detection. This allowed us to identify 2849 bubble seeps rising within 28 h from the seafloor across the 90 km² study site. Based on our calculations, the estimated bubble-driven episodic methane flux from the seafloor across the bay is 1,900 µMol m-2 d-1. Our study demonstrates that storm-associated fluctuations of hydrostatic pressure induce bulk gas-driven ebullitions. Given the extensive occurrence of shallow gas-hosting sediments in coastal seas, similar ebullition events probably take place in many parts of the Western Baltic Sea. However, these are likely to be missed during field investigations, due to the lack of high-quality data acquisition during storms, such that atmospheric inputs of marine-derived methane will be highly underestimated.

Eukaryotic replication origins as promoters of bidirectional DNA synthesis.

Recent work in yeast shows that eukaryotic origins of DNA replication are multipartite regulatory elements resembling promoters of transcription. As for the regulation of transcription, accessory transcription factors appear to function in concert with basic origin recognition factors to regulate initiation of DNA synthesis at specific subsets of origins. The participation of transcription factors in the regulation of DNA replication may facilitate temporal control of transcription and replication during the cell cycle, as well as providing a mechanism for integrating origin selection with the cellular transcriptional program.

Protein-DNA interactions at the major and minor promoters of the divergently transcribed dhfr and rep3 genes during the Chinese hamster ovary cell cycle.

In mammals, two TATA-less bidirectional promoters regulate expression of the divergently transcribed dihydrofolate reductase (dhfr) and rep3 genes. In CHOC 400 cells, dhfr mRNA levels increase about fourfold during the G1-to-S phase transition of the cell cycle, whereas the levels of rep3 transcripts vary less than twofold during this time. To assess the role of DNA-binding proteins in transcriptional regulation of the dhfr and rep3 genes, the major and minor dhfr-rep3 promoter regions were analyzed by high-resolution genomic footprinting during the cell cycle. At the major dhfr promoter, prominent DNase I footprints over four upstream Sp1 binding sites did not vary throughout G1 and entry into the S phase. Genomic footprinting revealed that a protein is constitutively bound to the overlapping E2F sites throughout the G1-to-S phase transition, an interaction that is most evident on the transcribed template strand. On the nontranscribed strand, multiple changes in the DNase I cleavage pattern are observed during transit through G1 and entry into the S phase. By using gel mobility shift assays and a series of sequence-specific probes, two different species of E2F were shown to interact with the dhfr promoter during the cell cycle. The DNA binding activity of one E2F species, which preferentially recognizes the sequence TTTGGCGC, did not vary significantly during the cell cycle. The DNA binding activity of the second E2F species, which preferentially recognizes the sequence TTTCGCGC, increased during the G1-to-S phase transition. Together, these results indicate that Sp1 and the species of E2F that binds TTTGGCGC participate in the formation of a basal transcription complex, while the species of E2F that binds TTTCGCGC regulates dhfr gene expression during the G1-to-S phase transition. At the minor promoter, DNase I footprints at a consensus c-Myc binding site and three Sp1 binding sites showed little variation during the G1-to-S phase transition. In addition to protein binding at sequences known to be involved in the regulation of transcription, genomic footprinting of the entire promoter region also showed that a protein factor is constitutively bound to the first intron of the rep3 gene.

RIP60 dimers and multiples of dimers assemble link structures at an origin of bidirectional replication in the dihydrofolate reductase amplicon of Chinese hamster ovary cells.

We show assembly of low and high multimers of HeLa cell nuclear protein, RIP60, at the origin of bidirectional replication (OBR) identified by Burhans, Vassilev, Caddle, Heintz and DePamphilis in Chinese hamster ovary cells. RIP60 binds a 5'-ATT-3' reiterated sequence downstream of the OBR and a second, homologous ATT sequence of opposite orientation situated within the OBR zone. Specifically bound structures were studied by conventional electron microscopy (EM) and quantitative scanning transmission electron microscopy (STEM). Dimers and multiples of dimers link the downstream binding site that overlaps a bent DNA sequence and the homologous upstream OBR sequence, looping out 700 bp of intervening DNA. Superposed dimers are found at individual unlinked sites, stabilized presumably through protein-protein interaction, and such superposition appears to occur also in the basic link structure. Along the loop, single crossovers and extended twists are observed by conventional EM. By STEM, loop DNA is laterally compacted, with diameter and mass equivalent to double-duplex DNA strands. Supercoiled 736 bp and 5243 bp circular DNAs assume similar laterally compacted geometries that are mostly absent from relaxed forms. These observations parallel the compacted, interwound superhelices viewed by cryo-electron microscopy in vitrified solutions containing magnesium ions, and provide structural evidence in agreement with that from conventional EM for superhelical tension in RIP60 loop DNA. Loop superhelicity could arise as a topological response to linking and suggests a functional role for link formation.

Ligand- and DNA-induced dissociation of RXR tetramers.

Unliganded bacterially expressed RXR alpha lacking the N-terminal region AB (apo-RXR alpha delta AB) was found in solution as an apparent mixture of 165 kDa tetramers and 42 kDa monomers which could be quantitatively separated by gel filtration and non-denaturing gel electrophoresis. Under identical conditions both liganded (holo-) and apo-RAR alpha delta AB were present as single monomeric species. apo-RXR alpha delta AB tetramers, as well as dimers of the apo-RXR ligand binding domain (apo-LBD), dissociated readily into monomers when exposed to their cognate ligand 9-cis retinoic acid (9c-RA). The apo-RXR alpha delta AB tetramer bound only transiently to a cognate DR1 response element, and was converted into DR1-apo-RXR alpha delta AB homodimer complexes indistinguishable from those generated by cooperative DNA binding of apo-RXR alpha delta AB monomers. In the absence of DNA, the addition of 9c-RA greatly accelerated the formation of heterodimers with the apo-RAR alpha delta AB heterodimerization partner. No RXR alpha delta AB or RAR alpha delta AB homodimers could be observed in solution, but upon mixing of the two receptor monomers stable heterodimers could be isolated which bound to DR5 response elements in a highly cooperative manner. In these heterodimers, RXR alpha delta AB interacted with its cognate ligand as efficiently as in RXR alpha delta AB homodimers. The presence of ligand did not alter the stability of RXR alpha delta AB homodimer or RXR alpha delta AB-RAR alpha delta AB heterodimer complexes on DR1 and DR5 response elements, respectively. These in vitro data support a model in which RXR tetramers could serve as an inactive pool with the dual function of: (i) rapidly supplying large amounts of RXR heterodimerization partners upon 9c-RA generation; and (ii) allowing RXR homodimer formation on "accessible" cognate response elements in the absence of 9c-RA. These events may represent a ligand-dependent regulatory mechanism controlling the availability of the promiscuous RXR dimerization partner that is engaged in multiple nuclear receptor signalling pathways.

Access to kidney transplantation. Has the United States eliminated income and racial differences?

We analyzed the effect of patient and dialysis unit characteristics on access to kidney transplantation using several different approaches, including an analysis of individual patient data from a systematic random sample of 2900 new dialysis patients from each year 1981 to 1985 (14721 patients total). Additional analyses focused on the composition of transplant waiting lists and aggregate data from a 1984 census of 1133 dialysis and transplant units. White, male, young, nondiabetic, high-income patients treated in smaller units are more likely to receive a cadaver transplant under Medicare than are other kidney patients. Profit status of the dialysis unit was not found to be correlated to access to transplantation, although size of the unit may be correlated to access. Future analysis should focus on whether patient access has been inappropriately compromised. Possible factors unexplored in this analysis include differential patient preferences and medical suitability, as well as differential medical access.

Delayed graft function: risk factors and implications for renal allograft survival.

Delayed graft function (DGF) may be associated with diminished kidney allograft survival. We studied the risk factors that lead to nonimmediate function of a renal allograft and the consequences of DGF on short- and long-term renal transplant survival. Data from the U.S. Renal Data System were used to measure the relationships among cold ischemia time, delayed graft function, acute rejection, and graft survival in 37,216 primary cadaveric renal transplants (1985-1992). These relationships were investigated using the unconditional logistic and Cox multivariate regression methods. Cold ischemia time was strongly associated with DGF, with a 23% increase in the risk of DGF for every 6 hr of cold ischemia (P<0.001). Acute transplant rejection occurred more frequently in grafts with delayed function (37% vs. 20%; odds ratio=2.25, P=0.001). DGF was independently predictive of 5-year graft loss (relative risk=1.53, P<0.001). The presence of both early acute rejection and DGF portended a dismal 5-year graft survival rate of 35%. Zero-HLA mismatch conferred a 10-15% improvement in 1- and 5-year graft survival regardless of early functional status of the allograft. However, the 5-year graft survival rate in HLA-mismatched kidneys without DGF was significantly higher than that of zero-mismatched kidneys with DGF (63% vs. 51%; P<0.001). DGF independently portends a significant reduction in short- and long-term graft survival. Delayed function and early rejection episodes exerted an additive adverse effect on allograft survival. The deleterious impact of delayed function is comparatively more severe than that of poor HLA matching.

Long-term renal allograft survival: prognostic implication of the timing of acute rejection episodes.

BACKGROUND: The timing of an acute rejection may have a variable impact on renal allograft survival. To determine whether the time of first acute transplant rejection (ATR) is an independent predictor of long-term allograft survival, we studied 31,600 first cadaveric renal transplants that were functional on the first transplant anniversary, from 217 U.S. centers. METHODS: Transplant patients were divided into four groups according to the time to the first ATR: no rejection in year 1 (group I); predischarge ATR (group II); first ATR between discharge and month 6 (group III); and first ATR in months 7-12 (group IV). RESULTS: Four-year allograft survival after year 1, estimated by a Cox proportional hazard model adjusting for 19 cofactors, was 78%, 72%, 69%, and 54% for groups I-IV, respectively (P<0.0001 for each comparison to group I). In those patients who had ATR episodes in more than one time period, later episodes were associated with worse long-term allograft survival, an observation that was independent of previous ATR episodes. CONCLUSIONS: We conclude that late occurrence of a first acute rejection portends a worse prognosis for allograft survival after the first year. Later rejections, in combination with previous rejections, also lead to worse long-term allograft survival. Unlike early ATRs occurring in the setting of supervised immunosuppression, late occurring ATR may reflect inadequate immunosuppression from noncompliant behavior or may reflect disruption or lack of immune tolerance to the allograft. Efforts to minimize late transplant loss require a combination of strategies directed at both immunologic and behavioral factors.

Prognosis after primary renal transplant failure and the beneficial effects of repeat transplantation: multivariate analyses from the United States Renal Data System.

BACKGROUND: Survival of transplant recipients after primary renal allograft failure has not been well studied. METHODS: A cohort of 19,208 renal transplant recipients with primary allograft failure between 1985 and 1995 were followed from the date of allograft loss until death, repeat transplantation, or December 31, 1996. The mortality, wait-listing, and repeat transplantation rates were assessed. The mortality risks associated with repeat transplantation were estimated with a time-dependent survival model. RESULTS: In total, 34.5% (n=6,631) of patients died during follow-up. Of these deaths, 82.9% (n=5,498) occurred in patients not wait-listed for repeat transplantation, 11.9% (n=789) occurred in wait-listed patients, and 5.2% (n=344) occurred in second transplant recipients. Before repeat transplantation, the adjusted 5-year patient survival was 36%, 49%, and 65% for type I diabetes mellitus (DM), type II DM, and nondiabetic end-stage renal disease, respectively (P<0.001; DM vs. nondiabetics). The adjusted 5-year patient survival was lower in Caucasians (57%, P<0.001) compared with African-Americans (67%) and other races (64%). The 5-yr repeat transplantation rate was 29%, 15%, and 19%, whereas the median waiting time for a second transplant was 32, 90, and 81 months for Caucasians, African-Americans, and other races, respectively (P<0.0001 each). Repeat transplantation was associated with 45% and 23% reduction in 5-year mortality for type I DM and nondiabetic end-stage renal disease, respectively, when compared with their wait-listed dialysis counterparts with prior transplant failure. CONCLUSIONS: The loss of a primary renal allograft was associated with significant mortality, especially in recipients with type I DM. Repeat transplantation was associated with a substantial improvement in 5-year patient survival. Recipients with type I DM achieved the greatest proportional benefit from repeat transplantation.

Renal transplantation in end-stage sickle cell nephropathy.

BACKGROUND: The role of renal transplantation as treatment for end-stage sickle cell nephropathy (SCN) has not been well established. METHODS: We performed a comparative investigation of patient and allograft outcomes among age-matched African-American kidney transplant recipients with ESRD as a result of SCN (n=82) and all other causes (Other-ESRD, n=22,565). RESULTS: The incidence of delayed graft function and predischarge acute rejection in SCN group (24% and 26%) was similar to that observed in the Other-ESRD group (29% and 27%). The mean discharge serum creatinine (SCr) was 2.7 (+/-2.5) mg/dl in the SCN recipients compared to 3.0 (+/-2.5) mg/dl in the Other-ESRD recipients (P=0.42). There was no difference in the 1-year cadaveric graft survival (SCN: 78% vs. Other-ESRD: 77%), and the multivariable adjusted 1-year risk of graft loss indicated no significant effect of SCN (relative risk [RR]=1.39, P=0.149). However, the 3-year cadaveric graft survival tended to be lower in the SCN group (48% vs. 60%, P=0.055) and their adjusted 3-year risk of graft loss was significantly greater (RR= 1.60, P=0.003). There was a trend toward improved survival in the SCN transplant recipients compared to their dialysis-treated, wait-listed counterparts (RR=0.14, P=0.056). In comparison to the Other-ESRD (RR=1.00), the adjusted mortality risk in the SCN group was higher both at 1 year (RR=2.95, P=0.001) and at 3 years (RR=2.82, P=0.0001) after renal transplantation. CONCLUSIONS: The short-term renal allograft result in recipients with end-stage SCN was similar to that obtained in other causes of ESRD, but the long-term outcome was comparatively diminished. There was a trend toward better patient survival with renal transplantation relative to dialysis in end-stage SCN.

Automated procedures for the quantitation of protein.

An entirely automated 96-well microplate-based system to perform procedures for the measurement of protein is described. This single instrument system utilizes a series of computer-controlled mechanical subsystems to move the plate, control incubations and dispense samples or reagents in order to perform the assay. This system allows the investigator to reproducibly perform these protein assays on large numbers of biological samples with minimal effort.

Pharmacokinetics and pharmacodynamics of melagatran, a novel synthetic LMW thrombin inhibitor, in patients with acute DVT.

Forty-eight patients with acute proximal deep vein thrombosis (DVT) were randomised to intravenous infusions for 4 to 6 days with melagatran, a novel synthetic low molecular weight thrombin inhibitor, or unfractionated heparin adjusted by the activated partial thromboplastin time (APTT). The aim of the study was to investigate the pharmacokinetics, pharmacodynamics and the safety of melagatran therapy at three different doses. Steady-state plasma concentrations were rapidly achieved and maintained throughout the infusion period. The mean plasma concentrations in the low, medium and high dose groups were 0.17, 0.31 and 0.53 micromol/l, respectively. The prolongation of APTT was stable during the melagatran infusions and correlated to the plasma concentration. Phlebographically verified regression of thrombus size measured as decrease in Marder score was seen after 4 to 6 days in 8 of 12 patients, 6 of 12 patients and 5 of 11 patients in the low, medium and high dose groups of melagatran and in 5 of the heparin-treated patients. In the low dose group with melagatran, thrombus extension was seen in one patient. At the dose levels studied, melagatran was well tolerated with no clinically significant bleeding problems, suggesting that melagatran could safely be given to patients suffering from DVT.

Effects of beta blockers on ventricular dysfunction after myocardial infarction: tolerability and survival effects.

At least 44 randomized trials of beta blockade in acute myocardial infarction have been reported. All of these trials excluded patients with moderate-to-severe clinical signs of acute left ventricular dysfunction (LVD). Several of the larger trials did include high-risk patients with a history of compensated heart failure or with symptoms and signs suggesting mild LVD. Data from these trials indicate that beta-blocker treatment was well tolerated by patients with LVD, both in the acute phase of myocardial infarction and during long-term follow-up treatment. Further, data for LVD patients indicate that mortality in the beta-blocker group was reduced by 20-30% when compared with the placebo group. A similar mortality reduction was obtained for the entire patient population in the trials. Because of the high mortality among patients with mild LVD, the absolute gain in numbers of lives saved per 100 patients treated with beta blockers is even larger than that in patients without LVD. Data from two long-term trials indicate marked (47% and 43%) reductions in the likelihood of sudden death among LVD patients treated with beta blockers. These results suggest that all patients with LVD who can tolerate beta blockade may benefit from treatment with these agents.

Early intravenous beta blockade and thrombolytics in acute myocardial infarction.

This article discusses therapy with beta blockade and thrombolytic agents in acute myocardial infarction. In large and well-controlled studies both treatment strategies have been shown to increase survival. Both therapies have also been demonstrated to be safe in acute myocardial infarction. Historically, the 2 different treatment strategies have been tested during different time periods, resulting in few studies with the main objective to study the combined effects of the 2 agents. From the data that are presently available, however, there is a clear suggestion of additive beneficial effect and the 2 treatments given in combination are well tolerated.

Audibility of an artificial third heart sound in relation to its frequency, amplitude, delay from the second heart sound and the experience of the observer.

The possibility of detecting synthetic third heart sounds was studied. A special unit was used that added a sound to a previously recorded phonocardiogram. The sound could be changed in frequency, amplitude and delay from the second heart sound. Four groups of observers--cardiologists, residents, nurses and students--listened to 32 random examples. Detection rate increased with experience of the observer (p less than 0.0001) as well as with amplitude (p less than 0.0001), frequency (p less than 0.0001) and delay of the sound (p less than 0.05). The sensitivity was highest among the cardiologists, but the specificity was not different between the groups. Data from this study indicate that the audibility of the third heart sound depends on several important factors. The sound should usually be audible, but variability of results were considerable even among experienced cardiologists. A quantified phonocardiographic recording should be used for validation.

Need for a large randomized trial to evaluate the effects of digitalis on morbidity and mortality in congestive heart failure.

Despite major advances in the prevention and treatment of cardiovascular diseases, the incidence and prevalence of congestive heart failure (CHF) have been increasing in recent years. As the average age of the population increases, the prevalence of CHF is expected to continue to increase. The number of deaths in which CHF was considered the underlying or contributing cause increased from 51,000 in 1955 to 274,000 by 1988 in the United States. Even accounting for population growth and an increase in the number of elderly, this represents a 2-fold increase. Additionally, CHF was responsible for about 643,000 hospitalizations in 1988. Digitalis is one of the drugs most commonly prescribed for CHF and has been used for greater than 200 years. In 1990, digoxin was one of the most commonly prescribed drugs in the United States, accounting for greater than 21 million prescriptions. There has been little decline in the drug's use over the last 5 years, indicating that newer treatments for CHF have not replaced the widespread use of digitalis. Despite these findings, considerable controversy surrounds the appropriateness of its role and value in treating CHF patients who are in sinus rhythm. A number of recent, uncontrolled studies have arrived at apparently contradictory conclusions concerning the effects of digitalis on mortality in postmyocardial infarction and heart failure patients. A large, double-blind, randomized, controlled clinical trial to evaluate the effects of digitalis on mortality, morbidity and quality of life is being sponsored by the National Heart, Lung, and Blood Institute in conjunction with the Department of Veterans Affairs Cooperative Studies Program.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects of metoprolol in acute myocardial infarction. A randomized, placebo-controlled multicenter study.

The central hemodynamic effects of metoprolol in acute myocardial infarction have been studied in a multicenter, double-blind, randomized trial. One hundred and ninety patients with acute myocardial infarction not previously on beta blockers with heart rate greater than 65 beats/min and blood pressure greater than 105 mm Hg and without clinical signs of serious heart failure were included. After insertion of a pulmonary artery catheter, patients were randomized to metoprolol, 15 mg intravenously, and 50 mg 4 times a day orally (n = 95) or placebo (n = 95) with a mean delay of 7.2 hours. Hemodynamic measurements were made at baseline and repeatedly during 24 hours. Heart rate, systolic blood pressure and cardiac index were all immediately reduced by 10 to 20% in the metoprolol group and the difference compared with placebo was maintained throughout the 24 hours (p less than 0.001). Pulmonary capillary wedge pressure (PCWP) in the metoprolol group increased from 13.7 +/- 6.7 to a peak of 15.5 +/- 5.5 mm Hg 30 minutes after injection. The difference compared with placebo was maintained for 8 hours (p less than 0.01). This increase was seen only in the patient group with initial PCWP below the median of 13 mm Hg. In patients with initial PCWP above the median a continuous decrease was observed in both the placebo and metoprolol groups. Thus high initial PCWP was not associated with intolerance to metoprolol. Based on hemodynamic measurements tolerance to metoprolol was good.

Haemodynamic effects of felodipine in congestive heart failure.

The acute and long term central haemodynamic effects of felodipine were studied in 9 patients with severe congestive heart failure (NYHA III-IV). A felodipine dose of 5 to 15 mg tid was individually titrated during a 24 to 48 hour catheterisation period. One patient received 5mg tid, 5 patients 10mg tid and 3 patients 15 mg tid. At rest the individual maximal dose was associated with a significant fall in systolic and diastolic blood pressure, pulmonary artery diastolic pressure, heart rate and systemic vascular resistance, while stroke volume was significantly increased. During upright submaximal (30-50 watts) bicycle exercise, the changes were principally the same with the addition of a significant increase of cardiac index. Six patients were re-evaluated after 30 days of continuous treatment. Their resting haemodynamics had returned to the control level but during exercise the significant changes in cardiac index, stroke volume and vascular resistance persisted. The results indicated a beneficial effect of felodipine in the treatment of heart failure, but further studies are needed.