Why do banks promise to pay par on demand?

We survey the theories of why banks promise to pay par on demand and examine evidence about the conditions under which banks have promised to pay the par value of deposits and banknotes on demand when holding only fractional reserves. The theoretical literature can be broadly divided into four strands: liquidity provision, asymmetric information, legal restrictions, and a medium of exchange. We assume that it is not zero cost to make a promise to redeem a liability at par value on demand. If so, then the conditions in the theories that result in par redemption are possible explanations of why banks promise to pay par on demand. If the explanation based on customers’ demand for liquidity is correct, payment of deposits at par will be promised when banks hold assets that are illiquid in the short run. If the asymmetric-information explanation based on the difficulty of valuing assets is correct, the marketability of banks’ assets determines whether banks promise to pay par. If the legal restrictions explanation of par redemption is correct, banks will not promise to pay par if they are not required to do so. If the transaction explanation is correct, banks will promise to pay par value only if the deposits are used in transactions. After the survey of the theoretical literature, we examine the history of banking in several countries in different eras: fourth-century Athens, medieval Italy, Japan, and free banking and money market mutual funds in the United States. We find that all of the theories can explain some of the observed banking arrangements, and none explain all of them

Clinical, Immunological and Treatment-Related Factors Associated with Normalised CD4+/CD8+ T-Cell Ratio: Effect of Naïve and Memory T-Cell Subsets

<div><p>Background</p><p>Although effective antiretroviral therapy(ART) increases CD4+ T-cell count, responses to ART vary considerably and only a minority of patients normalise their CD4+/CD8+ ratio. Although retention of naïve CD4+ T-cells is thought to predict better immune responses, relationships between CD4+ and CD8+ T-cell subsets and CD4+/CD8+ ratio have not been well described.</p><p>Methods</p><p>A cross-sectional study in a cohort of ambulatory HIV+ patients. We used flow cytometry on fresh blood to determine expanded CD4+ and CD8+ T-cell subsets; CD45RO+CD62L+(central memory), CD45RO+CD62L-(effector memory) and CD45RO-CD62L+(naïve) alongside routine T-cell subsets(absolute, percentage CD4+ and CD8+ counts), HIVRNA and collected demographic and treatment data. Relationship between CD4+/CD8+ T-cell ratio and expanded T-cell subsets was determined using linear regression analysis. Results are median[IQR] and regression coefficients unless stated.</p><p>Results</p><p>We recruited 190 subjects, age 42(36–48) years, 65% male, 65.3% Caucasian, 91% on ART(52.6% on protease inhibitors), 78.4% with HIVRNA<40cps/ml and median ART duration 6.8(2.6–10.2) years. Nadir and current CD4+ counts were 200(112–309) and 465(335–607) cells/mm³ respectively. Median CD4+/CD8+ ratio was 0.6(0.4–1.0), with 26.3% of subjects achieving CD4+/CD8+ ratio>1. Of the expanded CD4+ T-cell subsets, 27.3(18.0–38.3)% were naïve, 36.8(29.0–40.0)% central memory and 27.4(20.0–38.5)% effector memory. Of the CD8+ T-cells subsets, 16.5(10.2–25.5)% were naïve, 19.9(12.7–26.6)% central memory and 41.0(31.8–52.5)% effector memory. In the multivariable adjusted analysis, total cumulative-ART exposure(+0.15,p = 0.007), higher nadir CD4+ count(+0.011,p<0.001) and higher %CD8+ naive T-cells(+0.0085,p<0.001) were associated with higher CD4+/CD8+ ratio, higher absolute CD8+ T-cell(-0.0044,p<0.001) and higher %CD4+ effector memory T-cells(-0.004,p = 0.0036) were associated with lower CD4+/CD8+ ratio. Those with CD4+/CD8+ ratio>1 had significantly higher median %CD8+ naive T-cells; 25.4(14.0–36.0)% versus 14.4(9.4–21.6)%, p<0.0001, but significantly lower absolute CD8+ count; 464(384.5–567) versus 765(603–1084) cells/mm³, p<0.001.</p><p>Conclusions</p><p>Study suggests important role for naïve CD8+ T-cell populations in normalisation of the immune response to HIV-infection. How these findings relate to persistent immune activation on ART requires further study.</p></div

Correlation between CD4+ and CD8+ expanded T-cell subsets with CD4+/CD8, CD4+ and CD8+ T-cells.

<p>Correlation between CD4+ and CD8+ expanded T-cell subsets with CD4+/CD8, CD4+ and CD8+ T-cells.</p

Subject demographic and treatment characteristics.

<p>Data are median (IQR) unless otherwise stated, IDU-intravenous drug use, Ab-antibody, SAg-surface antigen,PI-protease inhibitor, N(t)RTI-nucleoside (-tide) reverse transcriptase, NNRTI-non- nucleoside reverse transcriptase inhibitor, INT-integrase inhibitor.</p

Adjusted multivariate linear regression analysis for factors associated with CD4+/CD8+ T-cell ratio.

†<p>Adjusted for age, gender, ethnicity, Hepatitis C status, and HIV RNA.</p>¥<p>Adjusted for age, gender, ethnicity, Hepatitis C status.</p><p>NB: Coefficients of %CD4+, %CD8+ T-cells and their subsets are per 1% increase.</p

T-cell subsets.

<p>Data are median (IQR) unless otherwise stated.</p

Univariate linear regression analysis for factors associated with CD4+/CD8+ T-cell ratio.

<p>IDU-Intravenous drug use, Ab-antibody, sAg-surface antigen, PI-protease inhibitor, N(t)RTI-nucleoside (-tide) reverse transcriptase, NNRTI-non-nucleoside reverse transcriptase inhibitor.</p><p>NB: Coefficients of %CD4+, %CD8+ T-cells and their subsets are per 1% increase.</p