Platelet PD-L1 suppresses anti-cancer immune cell activity in PD-L1 negative tumors.

Strategies that interfere with the binding of the receptor programmed cell death protein-1 (PD-1) to programmed death ligand-1 (PD-L1) have shown marked efficacy against many advanced cancers, including those that are negative for PD-L1. Precisely why patients with PD-L1 negative tumors respond to PD-1/PD-L1 checkpoint inhibition remains unclear. Here, we show that platelet-derived PD-L1 regulates the growth of PD-L1 negative tumors and that interference with platelet binding to PD-L1 negative cancer cells promotes T cell-induced cancer cytotoxicity. These results suggest that the successful outcomes of PD-L1 based therapies in patients with PD-L1 negative tumors may be explained, in part, by the presence of intra-tumoral platelets. Altogether, our findings demonstrate the impact of non-cancer/non-immune cell sources of PD-L1 in the tumor microenvironment in the promotion of cancer cell immune evasion. Our study also provides a compelling rationale for future testing of PD-L1 checkpoint inhibitor therapies in combination with antiplatelet agents, in patients with PD-L1 negative tumors.

Lactose drives Enterococcus expansion to promote graft-versus-host disease.

Disruption of intestinal microbial communities appears to underlie many human illnesses, but the mechanisms that promote this dysbiosis and its adverse consequences are poorly understood. In patients who received allogeneic hematopoietic cell transplantation (allo-HCT), we describe a high incidence of enterococcal expansion, which was associated with graft-versus-host disease (GVHD) and mortality. We found that Enterococcus also expands in the mouse gastrointestinal tract after allo-HCT and exacerbates disease severity in gnotobiotic models. Enterococcus growth is dependent on the disaccharide lactose, and dietary lactose depletion attenuates Enterococcus outgrowth and reduces the severity of GVHD in mice. Allo-HCT patients carrying lactose-nonabsorber genotypes showed compromised clearance of postantibiotic Enterococcus domination. We report lactose as a common nutrient that drives expansion of a commensal bacterium that exacerbates an intestinal and systemic inflammatory disease.

Can liquorice extract and herbal solution prevent colonic mucosa damage caused by robenacoxib in dogs?

UNLABELLED: Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used in animals, especially in dogs, to manage pain due to inflammatory disease. This study investigated whether plant drugs can prevent mucosal injury induced by robenacoxib. We used fifteen healthy beagle dogs (7 male and 8 female) aged 4 months, weighing 4.2-5.1 kg at the beginning of the study. Endoscopy and biopsy of the colon were performed before and on the 21 day treatment with robenacoxib (1), robenacoxib, herbal solution with liquorice extract (2), placebo - an empty capsule (3). There were 5 animals in each group. The greatest microscopic damage in the colon was observed in animals which received robenacoxib. Plant drug administration reduced the severity of lesions in the colon when administered with robenacoxib (ARI = - 0.15). CONCLUSION: concurrent administration of liquorice extract and plant solution with robenacoxib was associated with significant decreased severity of the robenacoxib-induced colonic mucosal lesions.

The effect of isotonic multiple electrolyte infusions during anesthesia on blood gas and enzymatic values in horses.

General equine anesthesia is accompanied by the risk of complications and even death. The majority of general anesthetics used in veterinary practice lead to arterial hypotension, decreased capillary perfusion and ventilatory depression leading to pathological changes referred to as postanesthetic myopathy. In this study an attempt was made to analyze changes in the perioperative and postoperative acid-base equilibrium and blood enzymatic activity in horses, subject to the intensity of the applied fluid therapy. The horses were divided into two groups: I--administered Ringer's solution during surgery at a dose of 6-10 ml/kg BW/h, II--Ringer's solution administered at a dose of 12-15 ml/kg BW/h. The results of the study indicate that use of hydrating fluid infusions during general anesthesia, including infusions without hypertensive substances, minimizes the risk of myocyte damage due to disturbances in local and general blood circulation.

Continued challenges with the use of erythropoiesis-stimulating agents in patients with cancer: perspectives and issues on policy-guided health care.

Erythropoiesis-stimulating agents (ESAs) are approved as an alternative to blood transfusions for treating anemia secondary to chemotherapy in patients with cancer. Recently, ESAs have been a source of controversy and confusion in the oncology community. This began when two European trials-the Breast Cancer Erythropoietin Survival Trial (BEST) and the Advanced Head-and-Neck Cancer Treated with Radiotherapy (ENHANCE) Study-raised safety concerns about decreased overall survival and increased venous thromboembolic events. In 2004, the United States Food and Drug Administration (FDA) convened its Oncologic Drugs Advisory Committee (ODAC) to review the data and reassess the risks and benefits of ESAs in patients with cancer. On May 10, 2007, ODAC reconvened when five trials (BEST, ENHANCE, AMG-20010103, AMG-20000161, and EPO-CAN-20) showed decreased overall survival. The briefing document noted that studies demonstrating detrimental effects on survival and/or tumor outcomes used an unapproved treatment regimen designed to maintain hemoglobin levels above 12 g/dl. On May 14, 2007, just days after the ODAC reconvened, the Centers for Medicare and Medicaid Services (CMS) released a proposed decision memo for a national coverage determination (NCD) imposing restrictions on ESAs. For health care providers, aspects of the proposed NCD were markedly inconsistent with FDA-approved ESA use and generally were considered ambiguous and unclear. Over objections of several professional associations and members of Congress, on July 30, 2007, CMS posted the final NCD and declared it effective immediately. When compared with FDA-approved labeling and professional society guidelines, the NCD revealed differences in ESA initiation, dosage escalation, dosage reduction, and definition of response. These discrepancies have generated confusion among health care providers, who are struggling over whether they can feasibly provide a dual system of care-one for Medicare patients and another for non-Medicare patients-that is evidence based. With this supplement, we hope to educate health care providers on the issues and challenges associated with policy-guided health care when discrepancies exist between the policy and evidence-based practice; offer guidance on implementing the NCD; and highlight the important role of pharmacists in the process.

Cyclodialysis in the treatment of nonhealing secondary glaucoma.

In cases of glaucoma with elevated intra ocular pressure, the first objective of treatment is its reduction and normalization. In cases when excessive pressure has resulted in a loss of vision, the aim of treatment is to attenuate the pain and to improve the comfort of the patient. This paper presents a case of glaucoma secondary to anterior uveitis, resistant to pharmacological treatment. A gonioscopic examination in both eyes revealed a narrowed filtration angle. An ophthalmoscopic examination of the fundus showed partial retinal detachment. The cyclodialysis procedure was performed in both eyes. In the post-surgery period, intraocular pressure (IOP) in both eyes showed a downward tendency. The treatment of glaucoma secondary to anterior uveitis, particularly in its advanced state, often requires the combination of pharmacological treatment with a surgical procedure. Positive results in maintaining the patency of the fistula were observed after the application of a steroid therapy and a regular massage of filtration bleb, which significantly contributed to maintaining IOP at a desired level.

Structural and electronic behavior of unprecedented five-coordinate iron(III) and gallium(III) complexes with a new phenol-rich electroactive ligand.

A new asymmetric pentadentate ligand was designed to impose low symmetry to trivalent ions. Five-coordinate Fe3+ and Ga3+ complexes were investigated by crystallographic, electrochemical, and electron paramagnetic resonance methods showing enhanced redox reversibility. Calculations were performed to account for the observed trends.

Influence of ligand rigidity and ring substitution on the structural and electronic behavior of trivalent iron and gallium complexes with asymmetric tridentate ligands.

Species 1-6 are [M(III)(L)2]ClO4 complexes formed with the PhO--CH=N-CH2-Py imines, (L(I))- and (L(tBuI))-, and PhO--CH2-NH-CH2-Py amines, (L(A))- and (L(tBuA))-, in which PhO- is a phenolate ring and Py is a pyridine ring and the prefix tBu indicates the presence of tertiary butyl groups occupying the positions 4 and 6 of the phenol ring. Monometallic species with d5 high-spin iron (1, 2, 3, 4) and d10 gallium (5, 6) were synthesized and characterized to assess the influence of the ligand rigidity and the presence of tertiary butyl-substituted phenol rings on their steric, electronic, and redox behavior. Characterization by elemental analysis, mass spectrometry, IR, UV-visible, and EPR spectroscopies, and electrochemistry has been performed, and complexes [FeIII(L(tBuI))2]ClO4 (2), [FeIII(L(tBuA))2]ClO4 (4), and [Ga(III)(L(tBuI))2]ClO4 (5) have been characterized by X-ray crystallography. The crystal structures show the imine ligands meridionally coordinated to the metal centers, whereas the amine ligands are coordinate in a facial mode. Cyclic voltammetry shows that the complexes with the ligands (L(tBuI))- and (L(tBuA))- were able to generate ligand-based phenoxyl radicals, whereas unsubstituted ligands displayed ill-defined redox processes. EPR spectroscopy supports high-spin configurations for the iron complexes. UV-visible spectra are dominated by charge-transfer phenomena, and imine compounds exhibit dramatic hyperchromism when compared to equivalent amines. The tertiary butyl groups on the phenolate ring enhance this trend. Detailed B3LYP/6-31G(d)-level calculations have been used to account for the results observed.

Laparoscopic cryptorchidectomy in dogs --report of 15 cases.

The study aimed at determining the usability of laparoscopic cryptorchidectomy in treating cases of simple cryptorchidism and neoplastic testes in dogs. The presence of one or both testes inside the peritoneal cavity was confirmed in this study by an ultrasonographic examination employing the use of a 6.5 MHz convex head. The surgeries were conducted on a group of 15 dogs. In 12 subjects a one-sided cryptorchidism was found, 9 of which had right-sided cryptorchidism. In 3 dogs, both-sided cryptorchidism was observed. In 3 cases, an increase in the size of the abdominal testes with the symptoms of hyperestrogenism and feminisation raised a suspicion of neoplastic changes (SCT) taking place, which was confirmed by a histopathological examination. A laparoscopic cryptorchidectomy with intracorporal ligation was performed in all the subjects. The spermatic cord and ductus deferens were occluded with a ligature of an absorbable material, and a manually applied knot.

Laparoscopic removal of gastric foreign bodies in dogs--comparison of manual suturing and stapling viscerosynthesis.

This study was an attempt to evaluate the application of various laparoscopic techniques of removing foreign bodies from the stomach in dogs in comparison to conventional laparotomy. The research was conducted on two groups of 10 dogs each with clinically confirmed foreign bodies in the stomach. In case of all patients, a laparoscopic instrument, EndoBag, was used for the removal of the foreign body from the stomach and the abdominal cavity. Manual suturing with the use of Szabo-Berci suturing kit was used for the gastrotomy wound closure in group I. In group II, linear staplers were used for viscerosynthesis. All patients were subjected to radiological assessment of tightness of anastomosis. No significant differences between the quality of the performed stomach anastomosis were shown. Therefore, the competitiveness of an economical manual suturing in comparison with the very expensive mechanical suturing preferred in human surgery was confirmed. The described procedures of laparoscopic gastrotomy seem to be applicable for removing foreign bodies from the stomach in a clinical veterinary practice.

Absence of previously reported variants in the SCNA (G88C and G209A), NR4A2 (T291D and T245G) and the DJ-1 (T497C) genes in familial Parkinson's disease from the GenePD study.

Parkinson's disease (PD) is a neurodegenerative disorder in which relatives of the probands are affected approximately 4 times as frequently as relatives of control subjects. Several genes have been implicated as genetic risk factors for PD. We investigated the presence of six reported genetic variations in the SCNA, NR4A2, and DJ-1 genes in 292 cases of familial Parkinson's disease from the GenePD study. None of the variants were found in the GenePD families. Our results suggest that other variants or genes account for the familial risk of PD within the GenePD study.

Repair of medial orbital wall fracture: transcaruncular approach.

The aim of this paper is to demonstrate the safety and the use of the transcaruncular approach as a surgical technique for managing a medial wall fracture. This approach was used in 40 patients with a isolated medial or a combined medial and inferior orbital wall fracture between September 1998 and September 2002. A computed tomographic scan was taken before and after surgery. The ocular motility and enophthalmos were checked before and after surgery. The transcaruncular approach provided the appropriate surgical exposure in all cases. Patients were followed up for a mean of 9.4 months (range, 524 months) after repairing the orbital wall fracture. Hertel exophthalmometry showed that among the 40 patients; 24 patients showed no enophthalmos. The enophthalmos ranged from 0.51 mm in 14 patients and 1.5 mm enphthalmos was noted in 2 patients. A clinically significant enophthalmos =2 mm was not found postoperatively. Preoperatively, 12 patients (30%) had a diplopia in the primary position of the gaze and 26 patients (65%) had a diplopia within 30 degrees of the gaze. Postoperatively, all patients had an orthotropia in the primary position but 4 patients (10%) had a residual diplopia either on the lateral gaze (2 patients) or the upgaze (2 patients). There were 2 cases of an implant misplacement. The transcaruncular approach provides a safe, rapid, and cosmetically pleasing surgical approach for managing a isolated medial wall fracture. When combined with the inferior transconjunctival approach, a combined medial and inferior orbital wall fracture can be successfully repaired.

A carcinoembryonic antigen-secreting adenocarcinoma arising within a retrorectal tailgut cyst: clinicopathological considerations.

Retrorectal tailgut cysts (TGC) develop from postanal fetal gut remnants. They have specific radiological and histopathological features that distinguish them from dermoid cysts, enteric duplication cysts, and teratomas. We report a patient with a carcinoembryonic antigen-producing adenocarcinoma arising within a TGC who underwent resection through a combined anterior laparotomy/posterior pelvic approach. Despite complete resection and delayed but complete functional recovery, diffusely metastatic disease was encountered 6 months after resection. Diagnostic, therapeutic, histopathological, and oncological implications of this illustrative case are discussed. It seems possible to use carcinoembryonic antigen measurements for treatment planning and for assessing treatment response for this rare disease. The described outcome also suggests that TGC can develop malignant degeneration and should be resected at the time of diagnosis.

Role of disulfide bridges in the folding, structure and biological activity of omega-conotoxin GVIA.

Omega-Conotoxin GVIA (GVIA), an N-type calcium channel blocker from the cone shell Conus geographus, is a 27 residue polypeptide cross-linked by three disulfide bonds. Here, we report the synthesis, structural analysis by (1)H NMR and bioassay of analogues of GVIA with disulfide bridge deletions and N- and C-terminal truncations. Two analogues that retain the crucial Lys-2 and Tyr-13 residues in loops constrained by two native disulfide bridges were synthesised using orthogonal protection of cysteine residues. In the first analogue, the Cys-15-Cys-26 disulfide bridge was deleted (by replacing the appropriate Cys residues with Ser), while in the second, this disulfide bridge and the eight C-terminal residues were deleted. No activity was detected for either analogue in a rat vas deferens assay, which measures N-type calcium channel activity in sympathetic nerve, and NMR studies showed that this was due to a gross loss of secondary and tertiary structure. Five inactive analogues that were synthesised without orthogonal protection of Cys residues as part of a previous study (Flinn et al. (1995) J. Pept. Sci. 1, 379-384) were also investigated. Three had single disulfide deletions (via Ser substitutions) and two had N- or C-terminal deletions in addition to the disulfide deletion. Peptide mapping and NMR analyses demonstrated that at least four of these analogues had non-native disulfide pairings, which presumably accounts for their lack of activity. The NMR studies also showed that all five analogues had substantially altered tertiary structures, although the backbone chemical shifts and nuclear Overhauser enhancements (NOEs) implied that native-like turn structures persisted in some of these analogues despite the non-native disulfide pairings. This work demonstrates the importance of the disulfides in omega-conotoxin folding and shows that the Cys-15-Cys-26 disulfide is essential for activity in GVIA. The NMR analyses also emphasise that backbone chemical shifts and short- and medium-range NOEs are dictated largely by local secondary structure elements and are not necessarily reliable monitors of the tertiary fold.

Examination of adenosine receptor-mediated relaxation of the pig coronary artery.

1. The adenosine receptors mediating relaxation of porcine isolated left anterior descending coronary arteries (LAD) and the effects of the level and type of preconstriction on the responses to adenosine analogues were examined in the present study. 2. Relaxation responses to the non-selective adenosine receptor agonist N-ethylcarboxamidoadenosine (NECA) were endothelium independent. N-Ethylcarboxamidoadenosine, GR 79236 (A1 receptor selective) and 8-cyclopentyl-1,3-dipropylxanthine (CGS 21680) (A2A receptor selective) produced full relaxation in LAD precontracted to 50% of the response to potassium depolarization with the thromboxane receptor agonist U46619. The order of potency was CGS 21680 = NECA > GR 79236, consistent with that defining the A2A receptor subtype. 3. 3,7-Dimethyl-1-propargylxanthine (DMPX; A2 receptor selective) competitively antagonized NECA and CGS 21680 with pKB values of 4.95 +/- 0.09 and 5.06 +/- 0.22, respectively. The A1 receptor selective antagonist 1,3-[3H]-dipropyl-8-cyclopentylxanthine (DPCPX) had no effect on NECA relaxation, even in the presence of DMPX. 4. The sensitivity to relaxation by NECA was dependent on the precontracting agent. Arteries precontracted with endothelin (ET)-1 were most sensitive to NECA, U46619-precontracted arteries were intermediate and KCl-precontracted arteries were least sensitive. 5. The potency of NECA was reduced when the preconstriction level was increased from 50 to 90% of maximum in U46619-precontracted arteries (pEC50 7.94 +/- 0.12 and 7.35 +/- 0.04, respectively) and, in KCl-precontracted arteries, both the potency and maximum effect of NECA were reduced when the preconstriction level increased from 50 to 80% of maximum (pEC50 7.52 +/- 0.13 and 6.91 +/- 0.26, respectively; maximum responses 82.5 +/- 10.2 and 23.9 +/- 3.6%, respectively, of the preconstricted tone). Relaxation responses to NECA were independent of the level of precontraction in ET-1-precontracted arteries. 6. In porcine LAD, relaxation responses to adenosine analogues were endothelium independent and were mediated via A2A adenosine receptors. Responses to NECA were dependent on both the level and type of preconstriction.

Roles of key functional groups in omega-conotoxin GVIA synthesis, structure and functional assay of selected peptide analogues.

The contributions of various functional groups to the pharmacophore of the N-type calcium-channel blocker, omega-conotoxin GVIA (GVIA), have been investigated using structural and in-vitro functional studies of analogues substituted at one or two positions with non-native residues. In most cases the structure of the analogue was shown to be native-like by 1H NMR spectroscopy. Minor conformational changes observed in some cases were characterized by two-dimensional NMR. Three functional assays (sympathetic nerve stimulation of rat isolated vas deferens, right atrium and mesenteric artery) were employed to monitor N-type calcium-channel activity. The data provide a more detailed picture of the roles in GVIA structure and activity of the crucial Lys2 and Tyr13, as well as all other positively charged residues, Tyr22, the hydroxyproline residues and the C-terminal amido moiety, many of which were identified as being important for activity in an alanine scan [Lew et al. (1997) J. Biol. Chem. 272, 12014-12023]. Substitutions of Lys2 with nonstandard amino acids and arginine quantified the roles of the length and charge of the Lys side chain. The orientation of the Tyr13 side chain and its hydroxyl moiety was shown to be important by substitution with d-Tyr and the d-form and l-form of the constrained analogue 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid [Tic(OH)]. The roles of the Hyp10 and Hyp21 hydroxyl groups, investigated by proline substitutions, appear to be more structural (as monitored by NMR) than functional, although small decreases in potency were observed in some assays. The reversibility of the channel blockade was also studied, and several analogues with faster wash-out characteristics than native GVIA were identified. Rapid reversibility (as in the case of omega-conotoxin MVIIA) may be beneficial for therapeutic applications. Disubstituted analogues revealed some interesting cooperative effects, which were not predicted from single-residue substitutions. A disubstituted chimera of GVIA and omega-conotoxin MVIIA was more potent than either native molecule. The more detailed description of the GVIA pharmacophore obtained here provides a better basis for the future design of truncated peptide and peptidomimetic analogues.

WISP genes are members of the connective tissue growth factor family that are up-regulated in wnt-1-transformed cells and aberrantly expressed in human colon tumors.

Wnt family members are critical to many developmental processes, and components of the Wnt signaling pathway have been linked to tumorigenesis in familial and sporadic colon carcinomas. Here we report the identification of two genes, WISP-1 and WISP-2, that are up-regulated in the mouse mammary epithelial cell line C57MG transformed by Wnt-1, but not by Wnt-4. Together with a third related gene, WISP-3, these proteins define a subfamily of the connective tissue growth factor family. Two distinct systems demonstrated WISP induction to be associated with the expression of Wnt-1. These included (i) C57MG cells infected with a Wnt-1 retroviral vector or expressing Wnt-1 under the control of a tetracyline repressible promoter, and (ii) Wnt-1 transgenic mice. The WISP-1 gene was localized to human chromosome 8q24.1-8q24.3. WISP-1 genomic DNA was amplified in colon cancer cell lines and in human colon tumors and its RNA overexpressed (2- to >30-fold) in 84% of the tumors examined compared with patient-matched normal mucosa. WISP-3 mapped to chromosome 6q22-6q23 and also was overexpressed (4- to >40-fold) in 63% of the colon tumors analyzed. In contrast, WISP-2 mapped to human chromosome 20q12-20q13 and its DNA was amplified, but RNA expression was reduced (2- to >30-fold) in 79% of the tumors. These results suggest that the WISP genes may be downstream of Wnt-1 signaling and that aberrant levels of WISP expression in colon cancer may play a role in colon tumorigenesis.

Structure-function relationships of omega-conotoxin GVIA. Synthesis, structure, calcium channel binding, and functional assay of alanine-substituted analogues.

The structure-function relationships of the N-type calcium channel blocker, omega-conotoxin GVIA (GVIA), have been elucidated by structural, binding and in vitro and in vivo functional studies of alanine-substituted analogues of the native molecule. Alanine was substituted at all non-bridging positions in the sequence. In most cases the structure of the analogues in aqueous solution was shown to be native-like by 1H NMR spectroscopy. Minor conformational changes observed in some cases were characterized by two-dimensional NMR. Replacement of Lys2 and Tyr13 with Ala caused reductions in potency of more than 2 orders of magnitude in three functional assays (sympathetic nerve stimulation of rat isolated vas deferens, right atrium and mesenteric artery) and a rat brain membrane binding assay. Replacement of several other residues with Ala (particularly Arg17, Tyr22 and Lys24) resulted in significant reductions in potency (<100-fold) in the functional assays, but not the binding assay. The potencies of the analogues were strongly correlated between the different functional assays but not between the functional assays and the binding assay. Thus, the physiologically relevant assays employed in this study have shown that the high affinity of GVIA for the N-type calcium channel is the result of interactions between the channel binding site and the toxin at more sites than the previously identified Lys2 and Tyr13.

Synthesis and characterization of a selective peptide antagonist of neuropeptide Y vascular postsynaptic receptors.

1. A cyclic dimeric nonapeptide neuropeptide Y (NPY) receptor antagonist, 1229U91, was synthesized by Fmoc chemistry and dimerised in solution. Its effects were assayed in mesenteric arteries from rats and mice, and in rat vas deferens. 2. Mesenteric arteries were cannulated and pressurised to 55 mmHg and the external diameters continuously measured. NPY, PYY, Leu31Pro34NPY and NPY(13-36) each caused concentration-related contractions with the order of potency PYY > or = Leu31Pro34NPY = NPY > NPY (13-36), consistent with the Y1 receptor subtype. 3. 1229U91 had no agonist activity in the arteries but caused a concentration-related rightward shift of NPY (mouse arteries) or Leu31Pro34NPY (rat) concentration-response curves. The antagonism was competitive with pKBS of 7.69 +/- 0.15 and 7.47 +/- 0.13 in the mouse and rat arteries, respectively. 4. Sympathetic nerves in the vas deferens were stimulated with a single electrical field pulse every 20 s and the twitch responses recorded. NPY, PYY, Leu31Pro34NPY and NPY(13-36) inhibited the twitches with the order of potency PYY > NPY > NPY(13-36) >> Leu31Pro34NPY, consistent with the Y2 receptor subtype. 5. 1229U91 inhibited the vas deferens twitch with a shallow concentration-response curve and a time-course of inhibition distinct from that of NPY. 1229U91 (30 microM) did not cause a rightward shift of the NPY concentration-response curve. 1229U91 is at least 5 orders of magnitude less potent in the vas deferens than in rat brain Y2 binding assays reported by others, suggesting that the brain and vas deferens Y2 receptors are different. 6. It is concluded that 1229U91 is a competitive antagonist of NPY Y1 vascular receptors and has additional properties that inhibit the electrically evoked twitch of the rat vas deferens.

Effect of cold storage in University of Wisconsin solution on the responses of porcine hepatic arteries to 5-hydroxytryptamine and bradykinin in vitro.

1. Responses to 5-hydroxytryptamine (5-HT), bradykinin and sodium nitroprusside (SNP) were examined in hepatic arteries of the pig 1 h after dissection (fresh) and following 24 h storage in either Ca(2+)-free Krebs solution or the cryopreservative University of Wisconsin (UW) solution. 2. In fresh arteries contracted to approximately 40% of the maximum response to potassium with U46619, a thromboxane A2-mimetic, concentration-response curves to 5-HT (10(-10)-10(-5) M) were biphasic, with relaxation at low concentrations (< 10(-8) M) and contraction at high concentrations. Bradykinin (10(-10)-10(-7) M) produced concentration-dependent relaxation of precontracted fresh arteries with no apparent constrictor response. 3. Following 24 h storage in Ca(2+)-free Krebs solution, relaxation responses to 5-HT and the sensitivity of the arteries to bradykinin were significantly reduced. Storage in UW solution did not affect relaxation responses to either 5-HT or bradykinin. Relaxation responses to SNP (10(-8)-10(-3) M) were unaffected by storage in either solution. 4. Treatment of fresh arteries with NG-nitro-L-arginine (L-NOARG, 10(-4) M) significantly attenuated the relaxation response to 5-HT and displaced the bradykinin concentration-response curve four fold to the right with no affect on its maximum relaxation. 5. From these results it is concluded that endothelial cell function is better preserved during cold storage in UW solution than in Ca(2+)-free Krebs solution.