Photoproduction of straight phi(1020) mesons on the proton at large momentum transfer

The cross section for straight phi meson photoproduction on the proton has been measured for the first time up to a four-momentum transfer -t = 4 GeV2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. At low four-momentum transfer, the differential cross section is well described by Pomeron exchange. At large four-momentum transfer, above -t = 1.8 GeV2, the data support a model where the Pomeron is resolved into its simplest component, two gluons, which may couple to any quark in the proton and in the straight phi.

Predictive value of host-specific donor helper T-cell precursor frequency for acute graft-versus-host disease and relapse in HLA-identical siblings receiving allogeneic bone marrow transplantation for hematological malignancies.

BACKGROUND: Acute graft-versus-host disease (aGVHD) is still one of the main causes of morbidity and mortality after allogeneic bone marrow transplantation. Attempts to avoid GVHD are associated with an increased risk of relapse, probably because the graft-versus-leukemia effect is also abrogated. It was recently suggested that a high frequency of host-specific donor helper T cell precursors (HTLp) might be predictive of significant aGVHD (grade > or = II). METHODS: We retrospectively studied the frequency of HTLp by means of simplified limiting-dilution analysis to determine its predictive value for aGVHD and relapse. Pre-bone marrow transplantation, host-specific donor HLTp frequencies were analyzed in 32 patients who had received marrow from HLA-identical siblings for hematological malignancies, in terms of aGVHD and relapse. RESULTS: HTLp frequencies were significantly higher in patients who had aGVHD > or = grade II (n=14) than in those without aGVHD (n=18) (P=0.007). Patients who relapsed (n=13) had significantly lower HTLp frequencies than those who did not relapse (n=19) (P<0.0001). The probabilities of relapse (Kaplan-Meier method) when the HTLp frequency was higher and lower than 1/200,000 were 0% and 88%, respectively (P<0.0001). CONCLUSIONS: The definition of HTLp cut-off values predictive of aGVHD and relapse should contribute to donor selection and could open the way to protocols adapting immunomodulation to the likely risk of aGVHD and relapse.

Twenty-four-hour intragastric acidity and plasma gastrin during 3-month treatment with omeprazole in healthy subjects.

BACKGROUND: Prolonged treatment with omeprazole 20 or 40 mg/day is sometimes required, especially for severe oesophagitis. However, information about long-term effects on intragastric acidity and plasma gastrin response with such drug regimens is scarce. METHODS: Sixteen healthy subjects (11 men, 5 women, mean age 29 years) randomly received either 20 or 40 mg of omeprazole once daily (at 08.00 h) for 3 months. Gastric pH was recorded every 6 s for 24 h from noon to noon under standardized conditions, and blood samples were collected hourly in order to determine the 24-h plasma gastrin response on day 0 (pre-entry), day 7, day 28 and day 90. RESULTS: From day 0 to day 7, 24-h median pH increased from 1.7 to 4.6 and mean percentage of time at pH < 4 decreased from 89% to 35% with omeprazole 20 mg. Respective values with omeprazole 40 mg were 1.9 to 4.3, and 89% to 34%. Inhibition of gastric acidity remained unchanged during the 3 months of treatment. Despite similar effects on the basis of 24-h analysis, the decrease in daytime acidity was slightly higher with omeprazole 40 mg than with omeprazole 20 mg. Twenty-four-hour integrated plasma gastrin significantly increased with both drug regimens between day 0 and day 7 (P < 0.01), and between day 7 and day 28 (P < 0.01) with omeprazole 40 mg; there was no significant increase between day 28 and day 90 with either of the drug regimens. CONCLUSION: Omeprazole 20 and 40 mg/day provides long-term stable acid suppression with a progressive increase in gastrin response, stabilizing after 2 months of treatment.

Effects of infusion of L-arginine into the left anterior descending coronary artery on acetylcholine-induced vasoconstriction of human atheromatous coronary arteries.

Hypercholesterolemia and atherosclerosis are conditions associated with impaired endothelium-dependent relaxation. In hypercholesterolemic animals, intravenous administration of L-arginine, the precursor of nitric oxide, normalizes endothelium-dependent vasodilator activity. In the present study, we questioned whether intracoronary administration of L-arginine in patients with coronary artery disease could improve coronary vascular reactivity to acetylcholine. Thirteen hypercholesterolemic patients with diffuse coronary atherosclerosis but nonstenotic lesions of the left anterior descending (LAD) coronary artery were investigated. Quantitative coronary angiography and subselective intracoronary Doppler flow velocity measurements were performed to determine LAD diameters and coronary blood flow. Intracoronary infusion of acetylcholine was performed during 3 consecutive 3-minute periods at incremental rates adjusted to achieve estimated final concentrations of 5 x 10(-7), 10(-6) and 5 x 10(-6) M. After evaluation of the response to acetylcholine, L-arginine was infused into the LAD at the rate of 25 mg/min (10(-3) M) and the same stepwise 3-minute infusions of acetylcholine were repeated during infusion of L-arginine. Infusion of acetylcholine induced a dose-dependent reduction of distal epicardial LAD diameter reaching -48.5 +/- 17% at 5 x 10(-6) M (p < 0.01 vs control values). L-arginine alone had no effect on the distal LAD diameter but attenuated acetylcholine-induced vasoconstriction to -21 +/- 9% at 5 x 10(-6) M acetylcholine (p < 0.01). Coronary blood flow showed a biphasic response to acetylcholine, increasing by 41 +/- 12% at 5 x 10(-7) M (p < 0.01) and decreasing by 21 +/- 13% at 5 x 10(-6) M (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-adrenergic contractile reserve as a predictor of clinical outcome in patients with idiopathic dilated cardiomyopathy.

To examine the ability of beta-adrenergic contractile reserve assessment to predict the outcome of patients with heart failure, a prospective study was undertaken in 35 patients with idiopathic dilated cardiomyopathy and radionuclide ejection fraction below 40%. During right- and left-sided catheterization, right atrial and left ventricular (LV) pressures, peak positive LV dp/dt, cardiac index, and plasma norepinephrine and epinephrine concentrations were measured at baseline. After a left main intracoronary infusion of dobutamine (25 to 200 micrograms.min-1), beta-adrenergic contractile responsiveness was assessed as the net increase in peak positive LV dp/dt (delta LV dp/dt). After the initial examination, patients were treated with diuretics, digitalis, and angiotensin converting enzyme inhibitors and then followed-up. After a mean follow-up period of 13 +/- 7 months, two groups of patients were distinguished: those who responded to medical therapy (group A, n = 26) and those with clinical deterioration (group B, n = 9) leading to death (n = 4) or heart transplantation (n = 5). Initial peak positive LV dp/dt, LV end-diastolic pressure, cardiac index, and LV ejection fraction were better in group A than in group B (p less than 0.001). Initial plasma norepinephrine and epinephrine concentrations were significantly higher and delta LV dp/dt was lower in group B than in group A (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of clonidine on the circulation and vasoactive hormones after aortic surgery.

After completion of abdominal aortic graft, 29 patients received an i.v. infusion of placebo (n = 16) or clonidine 7 micrograms kg-1 (n = 13) over 120 min in a double-blind study. Cardiovascular variables were measured and plasma samples obtained up to 5 h after arrival in the recovery room, for assay of noradrenaline, adrenaline, vasopressin and renin concentrations. Noradrenaline, adrenaline and vasopressin concentrations decreased in the clonidine group throughout recovery (P less than 0.001, 0.05 and 0.05, respectively, vs placebo). Heart rate was less in the clonidine group (P less than 0.01). There was no significant difference in mean arterial pressure between groups. Stroke volume was larger (P less than 0.01) and there were fewer episodes of hypertension (P less than 0.05) and tachycardia in the clonidine group. In addition, a reduction in the number of circulatory interventions (P less than 0.05) and episodes of shivering was noted in the clonidine group. Mean (SD) postoperative volume requirements were larger in the clonidine group (total postoperative input: clonidine 1462 (604) ml; placebo 1064 (348) ml (P less than 0.05]. These data are consistent with the observation that clonidine modifies endocrine and circulatory status after major surgery.

[6 months' results of coronary angioplasty after thrombolysis of myocardial infarction]. / Résultats à six mois de l'angioplastie coronaire faite après thrombolyse pour un infarctus du myocarde.

Transluminal coronary angioplasty (TCA) has become the treatment of choice of residual stenosis after thrombolysis for myocardial infarction, but the long-term results of TCA are imperfectly evaluated. Seventy patients underwent TCA after thrombolysis on account of a significant (greater than 50 p. 100) residual stenosis of the artery responsible for the infarction. TCA was performed less than 6 hours after the onset of symptoms in 15 patients who had neither clinical nor electrocardiographic evidence of reperfusion; 4 of these patients were in a state of cardiogenic shock. In the remaining patients TCA was performed 1 to 10 days (mean 3.2 days) after thrombolysis. A primary success was obtained in 64 patients (91 p. 100). Two patients had emergency aorto-coronary bypass. During their stay in hospital, 5 patients presented with symptoms of reocclusion which in 4 of them occurred less than 24 hours after TAC, and 2 of these 4 patients had to be reoperated upon; 2 patients died suddenly. During a 6 to 18 months' follow-up period (mean 10.5 months), the infarction recurred in 3 patients; the recurrence took place during the 3rd month in 2 of them (1 had another thrombolysis and later TAC) and during the 6th month in the third one. At 6 months, 4 patients were suffering from exertion angina and 2 asymptomatic patients had a positive exercise test. Fifty-two control coronary arteriographies were performed at 6 months. Thirteen patients (25 p. 100) had an occluded artery which was clinically silent in 11; 39 patients had a patent artery with restenosis in 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholinergic component of histamine-induced bronchoconstriction in newborn guinea pigs.

The magnitude of parasympathetic reflex-mediated bronchoconstriction during histamine infusion was compared in anesthetized paralyzed newborn and adult guinea pigs. The animals were ventilated using a constant-flow ventilator, and the conductance and compliance of the respiratory system were continuously monitored. We found that reactivity to histamine infusion was less in newborns than in adults, because newborns required a larger dose of histamine than adults (300 vs. 125 ng.kg-1.s-1) to produce an equivalent decrease in conductance (42 +/- 13 vs. 42 +/- 15%). Vagal interruption by bilateral cervical vagotomy or muscarinic blockade with atropine (3 mg/kg) significantly reduced the bronchoconstrictor response to histamine in adults. By contrast, neither vagotomy nor atropine significantly changed this response in the newborns. These results indicate the lack of a vagal component in the bronchoconstriction that histamine induced in the newborns. Their relative unresponsiveness to histamine might partly be related to the fact that, in the newborn, histamine mainly acts directly via its airway receptors.

[Early angioplasty in unstable angina. Results apropos of 60 consecutive patients]. / L'angioplastie précoce dans l'angor instable. Résultat à propos de 60 patients consécutifs.

Transluminal coronary angioplasty (TCA) is an attractive means of suppressing ischaemia in patients (pts) with unstable angina. Sixty consecutive pts underwent TCA 6 +/- 2.5 days on average after their admission. Only the ischaemic vessel was dilated (mean stenosis 79 p. 100). Primary success was obtained in 53 pts (88 p. 100) with 31 p. 100 of residual stenosis after TCA. Two pts underwent emergency surgery for extensive dissection; failure of traversing the stenotic segment occurred in 2 pts; 3 pts had myocardial infarction (MI) less than 1 h after TCA, 2 arteries have been recanalized by intracoronary streptokinase with persistence of a satisfactory result of TCA, the 3rd patient had occlusion of a secondary side branch. During their stay in hospital, 2 pts had coronary bypass for recurrent angina. After a follow-up period of 6 to 16 months (mean 10 months) early recurrence of angina was observed in a number of cases (before the sixth month in 7 pts). One pt developed MI during the fourth month. At six month, 10 or the initial 60 pts had undergone coronary bypass, 1 undilated pt was asymptomatic; out of 49 dilated pts (47 with one single TCA), 39 were symptom-free but 6 had a positive exercise test, 7 pts were in class II and one in class IV. At control coronary arteriography (46 pts) restenosis was present in 39 p. 100: 5 new TCA and 2 aorto-coronary bypasses were performed. At one year 28 pts had been followed up: 1 was in class IV and 1 in class II, the others being asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)