Search PubMed⌕ Search

Biomedical subjects

David Steinberg

Publications and source records attributed to David Steinberg.

At least 19 recordsLinked to original sources
PubMed2006

The allocation of organs donated by altruistic strangers.

In many transplant centers, organ retrieval from altruistic strangers is accepted practice; patients use Internet Web sites and other public media to locate strangers willing to give them an organ. It is argued that altruistic strangers should be permitted to select the recipients of their organs because 1) personal relationships are morally important; 2) it increases the number of available organs; and 3) no one is hurt by the process. Nonetheless, using public media to obtain organs may undermine equity in organ allocation. Organs donated by altruistic strangers do not go necessarily to patients who have the best immunologic match or the most urgent need or who have waited the longest. A publicly chartered organization should be established to coordinate live organ donation, including donation by altruistic strangers. Altruistic strangers should be educated to allocate their donated organs according to a prudent balance of equity and utility rather than their emotional response to a particular patient's plight, identity, or circumstances.

Adult↗
PubMed2005

A Porsche for patient accrual.

A $1,000 lottery ticket for a Porsche Boxster automobile was offered to the investigator who accrued the most patients to a Southwest Oncology Group prostate cancer protocol. This was done with the admirable intention of increasing patient accrual and improving the outlook for men with high risk prostate cancer. However, the offer of this prize also makes the statement that it is permissible to reward a doctor with an expensive automobile for putting patients on an oncology research protocol. Awarding an expensive prize for patient accrual risks eroding public confidence by creating the perception that clinical investigators, swayed by the allure of an expensive automobile, were motivated by material self-interest rather than the welfare of their patients and the advancement of medical science. I suspect that if the practice of expensive rewards for patient accrual became widespread the cumulative damage would ultimately outweigh the benefits.

Automobiles↗
PubMed2005

In silico identification of functional regions in proteins.

MOTIVATION: In silico prediction of functional regions on protein surfaces, i.e. sites of interaction with DNA, ligands, substrates and other proteins, is of utmost importance in various applications in the emerging fields of proteomics and structural genomics. When a sufficient number of homologs is found, powerful prediction schemes can be based on the observation that evolutionarily conserved regions are often functionally important, typically, only the principal functionally important region of the protein is detected, while secondary functional regions with weaker conservation signals are overlooked. Moreover, it is challenging to unambiguously identify the boundaries of the functional regions. METHODS: We present a new methodology, called PatchFinder, that automatically identifies patches of conserved residues that are located in close proximity to each other on the protein surface. PatchFinder is based on the following steps: (1) Assignment of conservation scores to each amino acid position on the protein surface. (2) Assignment of a score to each putative patch, based on its likelihood to be functionally important. The patch of maximum likelihood is considered to be the main functionally important region, and the search is continued for non-overlapping patches of secondary importance. RESULTS: We examined the accuracy of the method using the IGPS enzyme, the SH2 domain and a benchmark set of 112 proteins. These examples demonstrated that PatchFinder is capable of identifying both the main and secondary functional patches. AVAILABILITY: The PatchFinder program is available at: http://ashtoret.tau.ac.il/~nimrodg/

Algorithms↗
PubMed2004

Kidney transplants from young children and the mentally retarded.

Kidney donation by young children and the mentally retarded has been supported by court decisions, arguments based on obligations inherent in family relationships, an array of contextual factors, and the principle of beneficence. These justifications for taking organs from people who cannot protect themselves are problematic and must be weighed against our obligation to protect the vulnerable. A compromise solution is presented that strongly protects young children and the mentally retarded but does not abdicate all responsibility to relieve suffering. Guidelines are proposed that prohibit the retrieval of kidneys from young children and the mentally retarded but permit one exception. They would allow retrieval of a kidney when the consequence to a first order relative with whom the donor has a meaningful and valuable relationship is otherwise imminent death. This would be done in accordance with additional guidelines that minimize harm to the donor. Since most patients with end stage renal disease can be maintained on dialysis the need for a kidney to prevent death should be an uncommon occurrence. This compromise is proposed as a solution to a dilemma that exists because two ethical principles are in conflict and one cannot be honored without violating the other.

Child↗
PubMed2004

Mythic ideals.

Explore the source record for details and available documents.

Bioethics↗
PubMed2004

An "opting in" paradigm for kidney transplantation.

Almost 60,000 people in the United States with end stage renal disease are waiting for a kidney transplant. Because of the scarcity of organs from deceased donors live kidney donors have become a critical source of organs; in 2001, for the first time in recent decades, the number of live kidney donors exceeded the number of deceased donors. The paradigm used to justify putting live kidney donors at risk includes the low risk to the donor, the favorable risk-benefit ratio, the psychological benefits to the donor, altruism, and autonomy coupled with informed consent; because each of these arguments is flawed we need to lessen our dependence on live kidney donors and increase the number of organs retrieved from deceased donors. An "opting in" paradigm would reward people who agree to donate their kidneys after they die with allocation preference should they need a kidney while they are alive. An "opting in" program should increase the number of kidneys available for transplantation and eliminate the morally troubling problem of"organ takers"who would accept a kidney if they needed one but have made no provision to be an organ donor themselves. People who "opt in" would preferentially get an organ should they need one at the minimal cost of donating their kidneys when they have no use for them; it is a form of organ insurance a rational person should find extremely attractive. An "opting in" paradigm would simulate the reciprocal altruism observed in nature that sociobiologists believe enhances group survival. Although the allocation of organs based on factors other than need might be morally troubling, an "opting in" paradigm compares favorably with other methods of obtaining more organs and accepting the status quo of extreme organ scarcity. Although an "opting in" policy would be based on enlightened self-interest, by demonstrating the utilitarian value of mutual assistance, it would promote the attitude that self-interest sometimes requires the perception that we are all part of a common humanity.

Altruism↗
PubMed2004

Single surgeon experience with bilayer polypropylene mesh repair of inguinal hernia.

BACKGROUND: Open mesh repair of inguinal hernia has been shown to be an effective and safe method of hernia repair. In search of the 'ideal' method of open mesh hernia repair, many different methods of mesh placement have been developed. Laparoscopic hernia repair is reported to be superior to open repair in terms of postoperative pain and rehabilitation. These improved functional outcomes could be the result of placement of mesh in the preperitoneal space (underlay), rather than the laparoscopic method per se. A bilayer polypropylene mesh implant has been developed that provides onlay and underlay (preperitoneal) mesh layers. The present study reports the singular experience of a general surgeon with this bilayer polypropylene mesh implant. METHODS: A retrospective audit of the first 169 consecutive inguinal hernia repairs was conducted by mailed questionnaire and telephone interview. Data was collected on patient demographics, postoperative pain scores and complications. Patients with potential recurrences at the time of follow up were invited for clinical review. RESULTS: One hundred and three patients (71%) participated in the audit. Thirteen per cent of cases were for recurrent hernia. Median age was 60 years (range 21-99). Median length of follow up was 19 months (range 8-27). No recurrences were detected in the patients who underwent primary repair of inguinal hernia. CONCLUSION: Inguinal hernia repair with bilayer polypropylene mesh is safe and has low complication and recurrence rates.

Adult↗
PubMed2003

Priming rapacuronium: a comparison with rocuronium and mivacurium.

The aim of this study is to present the pharmacodynamics of the priming principle using rapacuronium and a comparison with rocuronium and mivacurium. After induction, 120 patients were randomly allocated to six similar groups. Groups 1 and 2 received rapacuronium 1000 micrograms.Kg-1 as a bolus or primed with 100 micrograms.Kg-1. To groups 3 and 4, rocuronium 400 micrograms.Kg-1 were given as a bolus or primed with 60 micrograms.Kg-1, finally mivacurium 100 micrograms.Kg-1 was used for groups 5 and 6 by bolus or primed with 10 micrograms.Kg-1. Neuromuscular function was monitored by electromyography and it was demonstrated that time to 80% blockade, is significantly shorter after priming: 137 (bolus) vs 101 seconds (priming) for rapacuronium, 160 vs 90 for rocuronium and 196 vs 118 for mivacurium. Onset time was also statistically accelerated by priming: 229 seconds vs 183, 289 vs 203 and 298 vs 252 respectively. No significant change was noticed in maximal blockade and clinical duration due to priming. During early onset, only the mivacurium patients showed a statistical difference in train of four fade between bolus and priming. In conclusion, priming hasten early and maximal effect produced by rapacuronium, rocuronium and mivacurium without any change in maximal blockade and clinical duration. Pre-synaptic effect does not explain consistently the mode of action of priming.

Adult↗
PubMedDate not supplied

Light modulates electric phenomena in hornet cuticle.

In the cuticle of live social hornets, such as Vespa orientalis (Hymenoptera, Vespinae), endogenous electric effects are encountered, i.e. voltages of 100-200 mV under illumination and currents amounting to several microamperes on its subjection to darkness-clearly a process of charging and discharging. Of the various wavelengths of sunlight, UV was found to be the most contributory to the active cuticular voltage generation. Throughout the warm season of the year--the active period in colonies of social hornets and wasps--colony members exit from the dark nest during the daytime and fly to the field under the hot sun for various foraging purposes, ultimately returning to the nest. Thus, each hornet, be it queen, worker or drone, probably undergoes daily cyclical process of electric charge and discharge in the exterior part of their integument, cuticle, which lasts up to 30-40 min. Such photoelectric phenomenon was detected in both live, ether-anaesthetized hornets and dead hornets, albeit in the latter the electric values recorded were lower. The present study addresses the possible impact of the phenomenon on vespan daily life and also compares it with a parallel occurrence in electric fish.

Animals↗