In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

Q: AIMS The present study aims to investigate the interaction between nitric oxide (NO) and hydrogen sulfide (H(2)S), the two important gaseous mediators in rat hearts.
METHODS AND RESULTS Intracellular calcium in isolated cardiomyocytes was measured with a spectrofluorometric method using Fura-2. Myocyte contractility was measured with a video edge system. NaHS (50 M, an H(2)S donor) had no significant effect on the resting calcium level, electrically induced (EI) calcium transients, and cell contractility in ventricular myocytes. Stimulating endogenous NO production with l-arginine or exogenous application of NO donors [sodium nitroprusside (SNP) and 2-(N,N-diethylamino)-diazenolate-2-oxide] decreased myocyte twitch amplitudes accompanied by slower velocities of both cell contraction and relaxation. Surprisingly, NaHS reversed the negative inotropic and lusitropic effects of the above three NO-increasing agents. In addition, the mixture of SNP + NaHS increased, whereas SNP alone decreased, the resting calcium level and the amplitudes of EI calcium transients. Angeli's salt, a nitroxyl anion (HNO) donor, mimicked the effect of SNP + NaHS on calcium handling and myocyte contractility. Three thiols, N-acetyl-cysteine, l-cysteine, and glutathione, abolished the effects of HNO and SNP + NaHS on myocyte contraction. Neither Rp-cAMP [a protein kinase A (PKA) inhibitor] nor Rp-cGMP [a protein kinase G (PKG) inhibitor] affected the effects of SNP + NaHS, suggesting a cAMP/PKA- or cGMP/PKG-independent mechanism.
CONCLUSION H(2)S may interact with NO to form a thiol sensitive molecule (probably HNO) which produces positive inotropic and lusitropic effects. Our findings may shed light on the interaction of NO and H(2)S and provide new clues to treat cardiovascular diseases.

A: Hydrogen sulfide interacts with nitric oxide in the heart: possible involvement of nitroxyl.
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Q: Kidney donor exchanges enable recipients with immunologically incompatible donors to receive compatible living donor grafts; however, the financial management of these exchanges, especially when an organ is shipped, is complex and thus has the potential to impede the broader implementation of donor exchange programs. Representatives from transplant centers that utilize the National Kidney Registry database to facilitate donor exchange transplants developed a financial model applicable to paired donor exchanges and donor chain transplants. The first tenet of the model is to eliminate financial liability to the donor. Thereafter, it accounts for the donor evaluation, donor nephrectomy hospital costs, donor nephrectomy physician fees, organ transport, donor complications and recipient inpatient services. Billing between hospitals is based on Medicare cost report defined costs rather than charges. We believe that this model complies with current federal regulations and effectively captures costs of the donor and recipient services. It could be considered as a financial paradigm for the United Network for Organ Sharing managed donor exchange program.

A: Managing finances of shipping living donor kidneys for donor exchanges.
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Q: Broadly neutralizing antibodies (bNAbs) to HIV-1 can prevent infection and are therefore of great importance for HIV-1 vaccine design. Notably, bNAbs are highly somatically mutated and generated by a fraction of HIV-1-infected individuals several years after infection. Antibodies typically accumulate mutations in the complementarity determining region (CDR) loops, which usually contact the antigen. The CDR loops are scaffolded by canonical framework regions (FWRs) that are both resistant to and less tolerant of mutations. Here, we report that in contrast to most antibodies, including those with limited HIV-1 neutralizing activity, most bNAbs require somatic mutations in their FWRs. Structural and functional analyses reveal that somatic mutations in FWR residues enhance breadth and potency by providing increased flexibility and/or direct antigen contact. Thus, in bNAbs, FWRs play an essential role beyond scaffolding the CDR loops and their unusual contribution to potency and breadth should be considered in HIV-1 vaccine design.

A:
Somatic Mutations of the Immunoglobulin Framework Are Generally Required for Broad and Potent HIV-1 Neutralization
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