Hyperdynamic microtubules, cognitive deficits, and pathology are improved in tau transgenic mice with low doses of the microtubule-stabilizing agent BMS-241027.

Tau is a microtubule (MT)-stabilizing protein that is altered in Alzheimer's disease (AD) and other tauopathies. It is hypothesized that the hyperphosphorylated, conformationally altered, and multimeric forms of tau lead to a disruption of MT stability; however, direct evidence is lacking in vivo. In this study, an in vivo stable isotope-mass spectrometric technique was used to measure the turnover, or dynamicity, of MTs in brains of living animals. We demonstrated an age-dependent increase in MT dynamics in two different tau transgenic mouse models, 3xTg and rTg4510. MT hyperdynamicity was dependent on tau expression, since a reduction of transgene expression with doxycycline reversed the MT changes. Treatment of rTg4510 mice with the epothilone, BMS-241027, also restored MT dynamics to baseline levels. In addition, MT stabilization with BMS-241027 had beneficial effects on Morris water maze deficits, tau pathology, and neurodegeneration. Interestingly, pathological and functional benefits of BMS-241027 were observed at doses that only partially reversed MT hyperdynamicity. Together, these data suggest that tau-mediated loss of MT stability may contribute to disease progression and that very low doses of BMS-241027 may be useful in the treatment of AD and other tauopathies.

Assessing psychosocial well-being of adolescents: a systematic review of measuring instruments.

BACKGROUND: The paradigm shift from the clinically deficit-oriented approach to that of educationally strength-based model in assessing adolescents' psychosocial well-being has brought about a recent increase in school-based health promotion and prevention initiatives. This prompted this systematic review of measuring instruments designed to assess psychosocial well-being of children and adolescents. METHODS: Using electronic databases on Academic Search Premier, MEDLINE, PROQUEST, PsycINFO, CINAHL Plus and Psychosocial and Health Instrument, a systematic review of literature of measuring instruments was conducted from their inception to December 2009 using the keywords of child, emotion, assessment, scale and measure. Measuring instruments from selected articles were critically appraised using a predetermined set of quality indicators which guided the rating of the psychometric properties of the instruments into grades of A, B, and C. The constructs of psychosocial well-being from the measuring instruments were categorized into themes. RESULTS: Twenty-nine out of the 908 articles met the inclusion criteria. Seventeen instruments identified from the selected articles were examined using preset quality indicators. In construct building, the themes identified from the strength-based instruments distinguished the construct of psychosocial well-being primarily into the dimensions of personal emotional competency and social functioning. In the ratings of psychometric properties, one instrument was rated 5A, five rated 4A and four rated 3A. For reliability testing, eight measures received grade A when their intraclass correlation is higher than 0.7; whereas only two instruments reported sensitivity and none investigated responsiveness. CONCLUSIONS: Strength-based measures focusing on social emotional behavioural outcomes open up a possibility to link up assessment with promotion of psychosocial well-being, away from clinical settings and into adolescents' homes, schools and community. Future research should focus more on investigating the sensitivity and responsiveness of measuring instruments using longitudinal design in efficacy studies to assess change in adolescents' psychosocial status over extended time.

Kaempferol stimulates large conductance Ca2+ -activated K+ (BKCa) channels in human umbilical vein endothelial cells via a cAMP/PKA-dependent pathway.

BACKGROUND AND PURPOSE: Kaempferol has been shown to possess a vasodilator effect but its mechanism of action remains unclear. In this study, experiments were carried out to study the effect of kaempferol on K+ channels in endothelial cells. EXPERIMENTAL APPROACH: K+ channel activities in human umbilical vein endothelial cells (HUVECs) were studied by conventional whole cell and cell-attached patch-clamp electrophysiology. KEY RESULTS: Kaempferol stimulated an outward-rectifying current in HUVECs in a dose-dependent manner with an EC50 value of 2.5+/-0.02 microM. This kaempferol-induced current was abolished by large conductance Ca2+ -activated K+ (BKCa) channel blockers, such as iberiotoxin (IbTX) and charybdotoxin (ChTX), whereas the small conductance Ca2+ -activated K+ (SKCa) channel blocker, apamin, and the voltage-dependent K+ (KV) channel blocker, 4-aminopyridine, had no effect. Cell-attached patches demonstrated that kaempferol increased the open probability of BkCa channels in HUVECs. Clamping intracellular Ca2+ did not prevent kaempferol-induced increases in outward current. In addition, the kaempferol-induced current was diminished by the adenylyl cyclase inhibitor SQ22536, the cAMP antagonist Rp-8-Br-cAMP and the PKA inhibitor KT5720, but was not affected by the guanylyl cyclase inhibitor ODQ, the cGMP antagonist Rp-8-Br-cGMP and the PKG inhibitor KT5823. The activation of BKCa channels by kaempferol caused membrane hyperpolarization of HUVECs. CONCLUSION AND IMPLICATIONS: These results demonstrate that kaempferol activates the opening of BKCa channels in HUVECs via a cAMP/PKA-dependent pathway, resulting in membrane hyperpolarization. This mechanism may partly account for the vasodilator effects of kaempferol.

Response of the kallikrein-kinin and renin-angiotensin systems to saline infusion and upright posture.

The possibility that bradykinin, a potent vasodilator, might be a physiological antagonist of the renin-angiotensin system was investigated. 11 norman subjects, ranging in age from 21 to 33 yr were studied. Seven of the subjects were given a 10 meq sodium, 100 meq potassium, 2500 ml isocaloric diet. After metabolic balance was achieved, they were infused with either 1 liter of 5 per cent glucose over 2 h or 2 liters of 0.9 per cent saline over 4 h. During the infusions, plasma renin activity (PRA), angiotensin II (A II), prekallikrein, bradykinin, and aldosterone levels were frequently determined. Plasma prekallikrein and kallikrein inhibitor did not change during the infusion of either glucose or saline. In subjects receiving saline, plasma bradykinin fell from 3.9 plus or minus 1.5 (SEM) ng/ml at 0 min to 0.93 plus or minus 0.2 at 30 min and 0.95 plus or minus 0.3 at 120 min. These changes paralleled the decrease in PRA over the same period (7.9 plus or minus 1.3 ng/ml/h to 5.6 plus or minus 0.8 at 30 min and 3.5 plus or minus 0.7 at 120 min). Similarly, A II fell from 113 plus or minus 12 pg/ml to 62 plus or minus 10 and 48 plus or minus 5, respectively, at 30 and 120 min. In contrast, the control group infused with glucose showed no change in bradykinin, A II, or PRA. Another four subjects were given a constant 200 meq sodium/100 meq potassium isocaloric diet. After metabolic balance was achieved, they were kept supine and fasting overnight. At 9 a.m. they assumed an upright position and began walking a fixed distance (200 ft) at a normal rate (3-4 ft/s). Plasma prekallikrein and kallikrein inhibitor did not change during the posture study. The plasma bradykinin rose from a base line of 0.54 plus or minus 0.01 (SEM) ng/ml to 0.96 plus or minus 0.13 at 20 min. 0.77 plus or minus 0.18 at 60 min, and 0.96 plus or minus 0.07 at 120 min. These changes parallel the increase in PRA over the same period (1.65 plus or minus 3.3 ng/ml/h to 3.6 plus or minus 0.85 at 20 min, 5.3 plus or minus 0.9 at 60 min, and 5.35 plus or minus 0.55 at 120 min). Likewise, the A II rose from 32.5 plus or minus 1.82 pg/ml to 50.8 plus or minus 3.6 at 20 min, 54.3 plus or minus 3.2 at 60 min, and 61.3 plus or minus 5.9 at 120 min. Thus, in sodium-depleted individuals, saline infusion produces a rapid fall of plasma bradykinin at a rate similar to that observed for a II and PRA. Conversely, in sodium-loaded individuals, assumption of upright posture leads to a parallel rise in A II, TPRA, and bradykinin. These studies indicate that there is a close correlation of bradykinin levels with renin activity and angiotensin II, in both acute sodium loading and assumption of upright posture, suggesting that these two systems may be physiologically interrelated.

Purification and partial characterization of prostaglandin D2 11-keto reductase in rabbit liver.

The cytoplasmic NADPH-dependent prostaglandin D2 11-keto reductase from rabbit liver was purified by a series of chromatographic procedures including isoelectric focusing. The enzyme catalyzed the conversion of prostaglandin D2 to prostaglandin F2 alpha and had a pH optimum of 7.0-7.5, and an isoelectric point of 5.8. The molecular weight was estimated to be 66 000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Enzymic activity was time and concentration dependent and required NADPH as cofactor.

Transformation of 15-hydroperoxyeicosapentaenoic acid to lipoxin A5 and B5, mono- and dihydroxyeicosapentaenoic acids by porcine leukocytes.

15-Hydroperoxy[1-14C]eicosapentaenoic acid derived from eicosapentaenoic acid (EPA) was incubated with suspensions of porcine leukocytes. Incubation with porcine leukocytes resulted in the formation of seven dihydroxy compounds, one monohydroxy and one hydroxyepoxy compound. After separation by reverse-phase and straight-phase HPLC, GC/MS analysis revealed that these metabolites were four isomers of 8,15-diHEPEs, two isomers of 14,15-diHEPEs, one isomer of 5,15-diHEPE, 15-HEPE and an epoxyalcohol: 13-hydroxy-14,15-epoxyeicosatetraenoic acid. In addition to the above metabolites, two trihydroxytetraene derivatives were also isolated. GC/MS and ultraviolet spectroscopy identified the two trihydroxypentaene derivatives as 5,6,15-trihydroxy-7,9,11,13,17-eicosapentaenoic acid (lipoxin A5) and 5,14,15-trihydroxy-6,8,10,12,17-eicosapentaenoic acid (lipoxin B5). This study demonstrated that the 15-hydroperoxide of EPA can be actively converted to various hydroxylated products via the 5-, 12- and 15-lipoxygenase as well as epoxyisomerase pathways in the porcine leukocytes.

Agonist-dependent generation of lipoxins from rat basophilic leukemia cell (RBL-1).

Incubation of RBL-1 cells in the presence of 15-HPETE and various agonists generated lipoxins and several isomers. Addition of either A23187, fMLP or PMA modulated the number of isomers and amount of lipoxins produced. Administration of A23187 yielded the largest amount of product (5.3 +/- 1.6 micrograms per 10(8) cells) and generated a total of six and three isomers of LXA4 and B4, respectively. This was 2-fold greater than fMLP, which produced a total of two isomers of LXA4 and LXB4. Addition of PMA generated only LXA4 (0.68 +/- 0.26 micrograms). This is similar to the control receiving only 15-HPETE. Biologically derived LXA4 (3 nM) isolated from RBL-1 incubations contracted a rat tail artery preparation to 12% of the maximum induced by phenylephrine (0.125 microM), whereas LXA4 standard (3 nM) elicited 17.6% of the maximum contraction. These results indicate that RBL-1 cells can utilize exogenous 15-HPETE to generate biologically active lipoxins. Further, the yield and isomers of lipoxins can be modified by different agonists.

Angiotensin II receptors, AT1 and AT2 in the rat epididymis. Immunocytochemical and electrophysiological studies.

Previous work from our laboratory has provided evidence for the presence of a tissue renin-angiotensin system in the rat epididymis. In the current investigation, the regional localization of angiotensin II receptors, type I (AT1) and type II (AT2) was studied immunocytochemically using specific anti-peptide antibodies against the second extracellular loops of AT1 and AT2 receptors, and pharmacologically using specific receptor antagonists in conjunction with the short-circuit current technique. The immunocytochemical results showed that AT1 and AT2 immunoreactivities were predominantly localized in the basal region of the epididymal epithelium. Electrophysiological studies using the short-circuit current technique demonstrated a stimulatory effect of basolaterally applied angiotensin II on the epididymal electrogenic ion transport. This effect was inhibitable by the addition of AT1 antagonist, losartan but not by AT2 antagonist, PD123177, indicating a functional role of AT1 in epididymal electrolyte transport. The present finding suggests that angiotensin II receptors may play an important role in the regulation of epididymal function.

Cation and anion channels in rat and human spermatozoa.

Ionic fluxes are thought to be important in the initiating process of gamete interaction such as acrosome reaction. Different populations of ion channels in rat and human spermatozoa were investigated using the planar lipid bilayer technique. Membrane proteins were isolated from rat and human sperm and inserted into lipid bilayer via fusion. We observed K(+) selective and Na(+)-selective channels, as well as divalent permeable cation channels in membrane preparations from rat sperm K+ channels, which were sensitive to the K+ channel blocker, tetraethylammonium (0.1 mM), exhibited a mean single channel conductance of 24 pS. Whereas, larger conductance, 109 pS, was found to be associated with Na+ channels. Low conductance anion channel, 15 pS, was also observed when permeant cations in the bathing solutions were substituted with N-methyl-D-glucamine leaving Cl- as the major permeant ion species. This channel exhibited a slower channel open and closed kinetics when compared to other cation channels. Both cation and anion channels with characteristics similar to that found in rat sperm were also observed in preparations from human sperm. The variety in the types of ion channels observed in rat and human spermatozoa suggests that ion channels may play different roles in sperm physiology and gamete interaction.

Functional expression of sperm angiotensin II type I receptor in Xenopus oocyte: modulation of a sperm Ca2+-activated K+ channel.

In addition to Ca2+ and K+ fluxes, angiotensin II (Ang II) has been shown to influence sperm motility. The present study investigated the involvement of angiotensin II type 1 receptor (AT1) in mediating the modulatory effect of Ang II on a sperm Ca2+-activated K+ channel expressed in Xenopus oocytes injected with RNAs of spermatogenic cells. Ang II at a concentration of 1 microM was found to potentiate the ionomycin-induced current, previously demonstrated to be mediated by a 'Maxi' Ca2+-activated K+ channel. However, at higher concentration, 20 microM, Ang II was found to suppress the ionomycin-induced current. Both potentiating and inhibitory effects of Ang II were blocked by losartan, a specific antagonist of AT1 receptors. Immunohistochemical studies further confirmed the presence of AT1 receptors in spermatogenic cells while expression of AT1 receptor mRNA was demonstrated by RT-PCR. These results suggest that Ang II may influence sperm motility as well as other sperm function by acting on AT1 receptors, and exerting potentiating and inhibitory effects on the Ca2+-activated K+ channels.

Electrogenic ion transport in the mouse endometrium: functional aspects of the cultured epithelium.

A primary culture of mouse endometrial epithelium grown on permeable supports was established and the electrogenic ion transport across the endometrial epithelium was studied using the short-circuit current (I(SC)) technique. Enzymatically isolated mouse endometrial cells were immunostained with epithelial cells markers, cytokeratins, indicating an epithelial origin of the culture. Mouse endometrial epithelial cells grown on Millipore filters formed polarized monolayers with junctional complexes as revealed by light and electron microscopy. The cultured monolayers exhibited an average basal I(SC) of 4.6 +/- 0.3 microA/cm2, transepithelial voltage of 2.7 +/- 0.2 mV and transepithelial resistance of 599 +/- 30 omega cm2. The basal current was reduced by 85% in Na+-free solution and 13% in Cl(-)-free solution. The basal current could also be substantially (57.7%) blocked by an apical Na+ channel blocker, amiloride (10 microM), suggesting that Na+ absorption largely contributed to the basal current. Apical addition of Cl- channel blocker, DPC (2 mM), also exhibited an inhibitory effect, 19.4%, on the basal I(SC), indicating minor involvement of Cl- secretion as compared to that of Na+ absorption. The cultured endometrial epithelium also responded to a number of secretagogues including adrenaline and forskolin with increases in the I(SC), which could involve substantial Cl- secretion. The present study has established a culture of mouse endometrial epithelium exhibiting predominantly Na+ absorption under unstimulated condition, and Cl- secretion in response to various secretagogues. This culture may be useful for studying various regulatory mechanisms of electrogenic ion transport across the endometrial epithelium.

Prostaglandin-related renin release from rabbit renal cortical slices.

The possibility that 6-keto-prostaglandin E1 (6-keto-PGE1) affects renin release was studied using rabbit renal cortical slices, a preparation that eliminates hemodynamic, neural, and blood-borne factors that might influence renin release. The medium used for incubating the slices was collected for renin assay at the end of each of four successive 20-minute periods. Test agents were added only once, at the beginning of Period 3 (experimental period). Between Periods 3 an 4 (recovery period), the medium was aspirated and the slices rinsed with Krebs solution before replacing the medium. Renin release did not change in vehicle-treated slices. Unlike the PGI2-induced changes, the effects of 6-keto-PGE1 on renin release were sustained in Period 4. Indomethacin potentiated renin stimulation induced by 10 microM concentrations of PGI2 and 6-keto-PGE1 in Period 3 and by 6-keto-PGE1 in Period 4. Using platelet antiaggregatory activity as an index of stability, we found that PGI2 was largely inactivated within 10 minutes under the conditions used for incubating the slices (pH 7.4, 37 degrees C), while 6-keto-PGE1 was stable. The results lend further support to the concept that 6-keto PgE1 is capable of releasing renin through a direct action.

6-keto PGE1: a possible metabolite of prostacyclin having platelet antiaggregatory effects.

Hepatic metabolism of prostacyclin (PGI2) results in the formation of several biologically inactive lipids and one stable product that has the same chromatographic and biological properties as authentic 6-keto PGE1. Both prostaglandins, 6-keto PGE1 and PGI2, have comparable potency in their antiaggregatory and disaggregatory effects on platelets. They contract the superfused rat stomach strip but differ in their effects on the bovine coronary artery, which is contracted by 6-keto PGE1 but relaxed by PGI2. Further, 6-keto PGE1 is considerably more stable than PGI2. Thus, 6-keto PGE1 could account for some of the prolonged effects occasionally seen with PGI2.

Acute effects of peritoneovenous shunting on plasma atrial natriuretic peptide in cirrhotic patients with massive refractory ascites.

Plasma immunoreactive alpha-human atrial natriuretic peptide (ANP) was measured in six cirrhotic patients with massive refractory ascites, under strict metabolic conditions, while they were receiving a 20-meq sodium diet, both before and at two-hour intervals for eight hours following peritoneovenous shunting (PVS). The mean preoperative level of ANP was 75 +/- 18 pg/ml, which was found to be significantly higher than the normal range for this laboratory (8 to 24 pg/ml) (p less than 0.05). This value was also significantly higher than the value of 21 +/- 5 pg/ml (p less than 0.05) obtained in six patients with cirrhosis but without ascites. Following shunt insertion, an immediate natriuresis and diuresis were observed in five of the six cirrhotic patients with refractory ascites. In these five, right atrial pressure and ANP rose immediately, followed by a rise in the level of urinary cyclic guanosine monophosphate. The sixth subject had a delayed rise in right atrial pressure, and correspondingly the rise in ANP, the diuresis, and natriuresis were delayed. The changes in ANP following PVS were positively correlated with changes in right atrial pressure (p less than 0.05), urinary cyclic guanosine monophosphate (p less than 0.05), urinary sodium excretion (p less than 0.05), and urine volume (p less than 0.01). These results suggest that ANP may be important in mediating the acute response to PVS.

Role of atrial natriuretic peptide in the natriuretic response to central volume expansion induced by head-out water immersion in sodium-retaining cirrhotic subjects.

PURPOSE: It is possible that abnormalities in atrial natriuretic peptide may be involved in the pathogenesis of sodium retention in edema states. We performed a study in a group of 12 sodium-retaining cirrhotic subjects to determine the role of this peptide in mediating differences in the natriuretic response to central volume expansion induced by head-out water immersion. PATIENTS AND METHODS: Each patient was maintained for seven days on a 20-mmol sodium intake, and then studied on both control and immersion days. On each day, measurements of the following were obtained: plasma atrial natriuretic peptide, hematocrit, electrolytes, creatinine, plasma renin activity, serum aldosterone, urinary cyclic guanosine monophosphate (cGMP), blood pressure, and pulse rate. RESULTS: In six subjects, immersion resulted in a marked natriuresis sufficient to induce negative sodium balance by the third hour, and these subjects were termed "responders." In these six patients, baseline pre-immersion levels of plasma renin activity and serum aldosterone were all below 3 ng/liter/second and 4 nmol/liter, respectively. In the other six subjects, the natriuretic response to immersion was markedly blunted and insufficient to induce negative sodium balance, and these subjects were termed "non-responders." In these subjects, baseline pre-immersion levels of plasma renin activity and aldosterone were all above 3.5 ng/liter/second and 5 nmol/liter, respectively, and were significantly elevated compared with the responders, and compared with the normal range for control subjects consuming the same sodium intake. In both groups of cirrhotic subjects, baseline levels of plasma atrial natriuretic peptide and cGMP excretion were significantly and comparably elevated compared with the normal range for control subjects ingesting the same sodium intake. Despite the marked difference in the natriuretic response to immersion in both responders and non-responders, there was a significant and comparable further elevation of plasma atrial natriuretic peptide and urinary cGMP excretion during immersion, compared with the control day. CONCLUSION: These results suggest that the relative resistance to the natriuretic action of atrial natriuretic peptide in the non-responders compared with the responders is mediated by anti-natriuretic factors acting at a level parallel with or beyond atrial natriuretic peptide release or coupling to its cGMP-linked receptors.

The effects of 16, 16 dimethyl prostaglandin E2 therapy alone and in combination with low-dose cyclosporine on rat small intestinal transplantation.

The use of prostaglandin E (PGE) in the setting of allotransplantation both clinically and experimentally has been suggested because PGE has significant immunosuppressive effects and potentially could lessen the toxic effects of cyclosporine. In the present study, we examined the immunosuppressive effects of 16,16 dimethyl prostaglandin E2 (dmPGE2) alone and in combination therapy with low-dose CsA to assess the clinical course, histology and expression of monocyte/macrophage procoagulant activity (PCA) following small intestinal transplantation in a heterotopic model of rat allograft rejection. Therapy with low-dose CsA (1 mg/kg) failed to prevent rejection and all animals reached a terminal state by day 26. In contrast, animals treated with high-dose CsA (10 mg/kg) showed no clinical or histological evidence of rejection and all animals survived. The dmPGE2 (100 micrograms/kg/twice daily) delayed the onset of rejection, but all animals developed severe rejection and subsequently died. Treatment of animals with low-dose CsA (1 mg/kg) in combination with dmPGE2 (100 micrograms/kg twice daily) resulted in a delay in the onset (P = 0.05) and a reduction in the intensity of allograft rejection (P = 0.0001) compared with either agent used alone. Monocyte/macrophage procoagulant activity levels correlated with the degree of rejection in all animals (P = 0.03). There was a statistically significant relationship between PCA levels and the time of onset of rejection and histologic grade of rejection in all groups. The data presented here, therefore, demonstrate a beneficial role for long-term combination therapy with CsA and PGE in small intestinal transplantation and strongly suggest a role for allogeneic induction of PCA in the pathogenesis of rejection.

The effects of cyclosporine and cyclosporine metabolites in experimental small intestinal transplantation.

Cyclosporine metabolites (CM) were compared with cyclosporine for their in vitro and in vivo immunosuppressive, nephrotoxic, and hepatotoxic effects using (A) in vitro mixed lymphocyte induction of monocyte/macrophage procoagulant activity (PCA), an accurate marker of allograft rejection; (B) in vitro toxic effects on renal cells in culture; and (C) a unidirectional rejection model of rat small intestinal transplantation (SIT). CM were composed of OL1, OL17, OL18, and two additional peaks C and H, (peak C: mass = 1235, 15.3% of total CM, peak H: mass = 1205, 6.3% of total CM). In vitro, CM fully suppressed the one-way mixed lymphocyte culture-induced PCA from 52.5 +/- 8.2 mU/10(6) PBM to the basal level 22.3 +/- 6.6 mU/10(6) PBM (P less than 0.01), which was comparable to CsA (21.3 +/- 5.5 mU/10(6) PBM). Lewis rats that had received Lewis-Brown Norway F1 hybrid intestinal allografts when treated with CM, demonstrated near-normal histology with minimal signs of rejection as compared with the fulminant clinical and histological rejection observed in the control (untreated and Cremaphor/NaCl treated) animals. PCA was markedly elevated in the control animals, 278 +/- 172 (untreated) and 160 +/- 98 mU/10(6) PBM (Cremaphor/normal saline treated), whereas CsA-treated allogeneic transplants expressed only basal levels of PCA (14.0 +/- 4 mU/10(6) PBM) (P less than 0.01), associated with normal histology. CM-treated animals expressed PCA levels of 27.0 +/- 10 mU/10(6) PBM, which was significantly different from both control and CsA-treated animals (P less than 0.01). In contrast to CsA-treated animals, CM-treated allogeneic transplants demonstrated no apparent renal or hepatic toxicity, as measured by blood urea nitrogen (25.3 +/- 9.5 vs. 10.0 +/- 5.3 mg/dl), alkaline phosphatase (160.7 +/- 29.3 vs. 100.3 +/- 19.5 U/L), and aspartate transaminase (96.7 +/- 23.7 vs. 61.7 +/- 11.7 U/L) (P less than 0.01). Similarly, in contrast to CsA, CM had minimal or no toxicity in renal epithelial and mesangial cells in culture, as measured by minimal or no inhibition of DNA, RNA, and protein synthesis. These results suggest that CM have potent immunosuppressive properties with no apparent nephrotoxicity and hepatotoxicity in vitro and in vivo.

Age-related differences in the effects of cyclosporine on lymphocyte intracellular free calcium.

The effect of cyclosporine on lymphocyte intracellular free calcium [( Ca2+]i) is controversial, and potential age-related differences in lymphocyte CsA sensitivity have not been studied. We measured the mitogen-induced change in [Ca2+]i in peripheral blood lymphocytes (PBLs) following intravenous CsA infusion (5 mg/kg) in neonatal pigs and found a significantly reduced calcium response compared with control (P = 0.02). This was associated with an elevation in resting [Ca2+]i in the neonatal PBLs 24 hr following the CsA infusion (P = 0.02). These changes in lymphocyte [Ca2+]i were associated with suppression of cell proliferation. Neonatal PBLs in mixed lymphocyte cultures showed a greater PHA-induced change in [Ca2+]i (delta[Ca2+]i) compared with mature PBLs (P = 0.0007). The addition of CsA (1 microgram/ml) to mitogenic- and allogeneic-stimulated cultures did not affect resting [Ca2+]i or delta[Ca2+]i in either neonatal or mature PBLs. Our results demonstrate significant differences in calcium responses in neonatal lymphocytes following CsA infusion and allogeneic stimulation. This implies that there are age-related differences in CsA effects at or proximal to the level of calcium release and/or sequestration in the lymphocyte signal transduction pathway, and that elevated resting intracellular calcium levels may be indicative of reduced responsiveness, possibly through feedback inhibition of tyrosine kinase activity.

The use of percutaneous transluminal angioplasty in hepatic artery stenosis after transplantation.

Graft ischemia following liver transplantation is associated with a high incidence of morbidity and mortality. The present report concerns a group of seven patients in whom an anastomotic stenosis of the hepatic artery was identified. Three patients had unexplained allograft dysfunction at a median time of 28 days (range 13-64 days), and 3 had a biliary leak at a median time of 42 days after liver transplantation (range 35-270 days). In one patient the stenosis was diagnosed by routine Doppler ultrasound one week after transplant. Management was by percutaneous transluminal angioplasty at a median time of 35 days (range 13-270 days) after transplantation. After angioplasty there was a marked improvement in clinical appearance, liver function, and liver histology in 5 of the 7 patients. Those patients who had a biliary leak subsequently developed strictures that eventually required biliary tract reconstruction (hepaticojejunostomy) in two and retransplantation in one. Percutaneous transluminal angioplasty is an effective way of improving arterial blood flow in cases of anastomotic stenosis, reducing the likelihood of complete occlusion by thrombosis. If recognized early and treated promptly ischemic changes in the graft can resolve and the development of biliary strictures may be avoided.