The Journal of clinical investigation
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Excess NO generation plays a major role in the hypotension and systemic vasodilatation characteristic of sepsis. Yet the kidney response to sepsis is characterized by vasoconstriction resulting in renal dysfunction. We have examined the roles of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) on the renal effects of lipopolysaccharide administration by comparing the effects of specific iNOS inhibition, -N6-(1-iminoethyl)lysine (L-NIL), and 2,4-diamino6-hydroxy-pyrimidine vs. nonspecific NOS inhibitors (nitro- -arginine-methylester). cGMP responses to carbamylcholine (CCh) (stimulated, basal) and sodium nitroprusside in isolated glomeruli were used as indices of eNOS and guanylate cyclase (GC) activity, respectively. ⋯ No differences were observed in eNOS mRNA expression among the experimental groups. Selective iNOS inhibition prevents reductions in GFR, whereas nonselective inhibition of NOS further decreases GFR. These findings suggest that the decrease in GFR after LPS is due to local inhibition of eNOS by iNOS, possibly via NO autoinhibition.
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The success of orthotopic liver transplantation is dependent on multiple factors including MHC tissue compatibility and ischemic/reperfusion injury. Ischemic/reperfusion (I/R) injury in the liver occurs in a biphasic pattern consisting of both acute phase (oxygen free radical mediated) and subacute phase (neutrophil-mediated) damage. Although numerous studies have given insights into the process of neutrophil recruitment after I/R injury to the liver, the exact mechanism that initiates this subacute response remains undefined. ⋯ Kinetic analysis of T cell infiltration in the livers of BALB/c mice demonstrated a fivefold increase in the number of hepatic CD4(+) T-lymphocytes within the first hour of reperfusion with no significant change in the number of CD8(+) T-lymphocytes. In summary, these results implicate CD4(+) T-lymphocytes as key regulators in initiating I/R-induced inflammatory responses in the liver. Such findings have implications for therapy directed at the early events in this inflammatory cascade that may prove useful in liver transplantation.