Compact self-illuminated image upconversion system based on intracavity second-harmonic generation.

We present an image upconversion system based on intracavity Type II second-harmonic generation to create an image in the visible spectrum of a target illuminated by an infrared laser. The system has the novelty of being self-illuminated. It uses some fractional leaking power of the infrared laser to illuminate a target located in the object focal plane of the system, and to couple back a created infrared target image to an intracavity nonlinear crystal, where it mixes with the cavity laser beam to obtain a second-harmonic image, visible with a silicon CCD camera. For a proof of concept, we have built a system based on a diode-pumped Nd3+:YVO4 continuous-wave (cw) laser and an intracavity KTP crystal to upconvert 1342 nm target images to 671 nm. The upconverted cw power allowed us to capture real-time video in a standard nonintensified CCD camera, with 2.5 W of a diode pump.

Myocardial Epstein-Barr virus-associated cardiac smooth-muscle neoplasm arising in a cardiac transplant recipient.

Epstein-Barr virus-associated smooth muscle proliferations have been reported in immunosuppressed patients with acquired immunodeficiency syndrome and after organ transplantation. We report here a case of a histologically benign case arising in a 48-year-old male who had received immunosuppressive therapy 4 years earlier, after cardiac transplantation. In the necropsy performed for unrelated reasons, an incidental left intramyocardial tumor was discovered. The presence of Epstein-Barr virus was confirmed by EBER-1 in situ hybridization and polymerase chain reaction. To the best of our knowledge, this is the first case of an Epstein-Barr virus-associated smooth muscle proliferation arising in the heart after cardiac transplantation and should be added to the potential complications of this kind of procedure.

Effects of verapamil and manganese on the vasoconstrictor responses to noradrenaline, serotonin and potassium in human and goat cerebral arteries.

The effects of verapamil and manganese (Mn2+) on the noradrenaline (NA), serotonin (5-HT) and potassium (K+)-induced contractions were studied in human and goat cerebral arteries. Verapamil and Mn2+ relaxed both kinds of cerebral vessels previously contracted with 10(-5) M NA, 10(-5) M 5-HT and 75 mM K+. The ID50 (50% inhibition of maximum contraction) was around 10(-7) M for the organic antagonist and 10(-3) M for the inorganic one. The ID50 for the Ca2+ antagonists in K+-induced contractions was smaller than that for NA and 5-HT-evoked contractions. Preincubation of segments with verapamil (10(-6) M) or Mn2+ (2 X 10(-3) or 5 X 10(-3) M) caused inhibition of the contractions evoked by the three agents that was greater in the case of K+. The inhibitory effects of verapamil were reversed by adding Ca2+ to the bath. The removal of Ca2+ from the extracellular medium reduced the contractions elicited by the three vasoconstrictor agents in both cerebral blood vessels. This reduction was greater for K+ than for the other two. These results indicate that both cerebral vessels are very susceptible to Ca2+ omission and to Ca2+ entry blockers such as verapamil and Mn2+, which could be of interest to treat cerebral vasospasm.

Effect of subarachnoid hemorrhage on contractile responses and noradrenaline release evoked in cat cerebral arteries by histamine.

This study analyzes the changes induced by subarachnoid hemorrhage (SAH) on the contractile responses and the noradrenaline release evoked in cat cerebral arteries by histamine. The dose-dependent vasoconstriction induced by histamine on the cerebral arteries of normal cats was significantly reduced by diphenhydramine and phentolamine. When SAH was produced 3 and 7 days before the experiment, the histamine-induced vasoconstriction also decreased. Thereafter, a tendency to normalization in the contractile vascular responses was observed such that in 15 days after the hemorrhage it was not significantly different from that found in controls animals. The decrease in the contractile responses to histamine provoked by SAH was similar to that seen after pretreatment with intracisternal injections of 6-hydroxydopamine. The amount of radioactivity released by histamine following preincubation with 3H-noradrenaline from the cerebral arteries of cats exposed to SAH 3, 7, and 15 days before the experiment was significantly reduced when compared with controls. Moreover, the basal level of tritium release and the radioactivity retained at the end of the experiment were also decreased after SAH. These decreases were less marked 15 days after SAH. Intracisternal injections of 6-hydroxydopamine 3, 7, and 15 days prior to the assay, and the removal of both superior cervical ganglia 15 days before the experiment, also markedly reduced these three parameters. These results indicate that histamine releases noradrenaline from cat cerebral arteries, and SAH produces a transient denervation of the perivascular adrenergic nerve endings. The inhibition of the histamine-induced vasoconstriction observed after SAH might be explained by the impairment of the indirect adrenergic mechanism involved in the overall contractile response elicited by this amine in cerebral arteries. According to the present findings, histamine does not seem to play a significant role in the production of the cerebral vasospasm occurring after SAH.

Effect of pentobarbital on the reactivity of isolated human cerebral arteries.

The authors have analyzed the effect of pentobarbital (10(-5) M to 10(-3) M) on the contractile activity of isolated human cerebral arteries. Pentobarbital was found to inhibit both the spontaneous mechanical activity and the basal tone of these vessels. Relaxation induced by this drug was dose-dependent, and was more marked when the arterial tone was previously increased with noradrenalin, potassium chloride, or 5-hydroxytryptamine. In addition, pentobarbital inhibits, in a dose-dependent manner, the contractions elicited by these vasoconstrictor agents. The present findings indicate that barbiturates decrease cerebrovascular reactivity, and disagree with the hypothesis that these drugs reduce raised intracranial pressure by means of exerting a direct constrictive effect on the cerebral arteries.

Interference of pentobarbitone with the contraction of vascular smooth muscle in goat middle cerebral artery.

Pentobarbitone (10(-5) to 10(-3) M) decreased the basal tone of vascular smooth muscle of goat middle cerebral artery in a dose-dependent manner as well as relaxing established contractions induced by noradrenaline (NA) (10(-5) M), 5-hydroxytryptamine (5-HT) (10(-5) M) and KCl(120 mM). Preincubations with pentobarbitone reduced the contractions evoked by these three agents in a dose-dependent way. It also decreased Ca2+ -induced contractile responses in K+ -depolarized arteries and 5-HT-Ca2+ and NA-Ca2+ contractions dose-dependently. Contractions induced by K+ were more sensitive to the depressant actions of the drug than those produced by NA and 5-HT. The small contractions evoked by K+ and 5-HT in Ca2+ -free medium were also reduced in its presence. The antagonism Ca2+ -pentobarbitone was insurmountable. These results suggest that the drug interferes with Ca2+ entry and Ca2+ release from cells stores, and therefore with the smooth muscle contractions.

Dual-wavelength green laser with a 4.5 THz frequency difference based on self-frequency- doubling in Nd3+ -doped aperiodically poled lithium niobate.

We report a dual-wavelength continuous-wave laser at 542.4 and 546.8 nm based on an Nd(3+)-doped aperiodically poled lithium niobate crystal. Two fundamental infrared (IR) wavelengths at 1084.8 and 1093.6 nm are simultaneously oscillated and self-frequency-doubled to green. The aperiodic domain distribution patterned in the crystal allows for quasi-phase matched self-frequency-doubling of both IR fundamentals while avoiding their sum-frequency mixing.

Contractile responses and noradrenaline release evoked by serotonin in cat femoral artery: influence of pentobarbital.

1. 5-Hydroxytryptamine (5-HT) induced dose-dependent contractions in the isolated cat femoral artery, which were reduced by LSD, methysergide, phentolamine and reserpine pretreatment (only at low doses). 2. Pentobarbital (PB) and Mn/+ relaxed the arteries previously contracted with 5-HT. These drugs reduced the contraction evoked by this amine as it was Ca2+-suppression. 3. High concentrations of 5-HT and K+ induced tritium release from vessels prelabelled with 3H-noradrenaline. Ca2+-deprivation and PB unmodified the release caused by 5-HT, but that elicited by K+ was abolished. 4. These data indicate that 5-HT-induced contraction is essentially due to direct interaction of this agent with 5-HT-receptors, and that PB interferes with Ca2+ entry to the cell.

Interference of pentobarbital and thiopental with the vascular contraction and noradrenaline release in human cerebral arteries.

Thiopental and pentobarbital induced dose-dependent vasodilations in human cerebral arteries previously contracted with noradrenaline (NA), serotonin (5-HT) and KCl. Preincubation with both barbiturates decreased the contractions evoked by the three agents. Pentobarbital and thiopental reduced the Ca2+-induced contractile effects in K+-depolarized arteries and 5-HT-Ca2+ and NA-Ca2+ contractions dose-dependently. The tritium release evoked by K+ from these vessels prelabelled with [3H]NA was significantly reduced by both barbiturates at 10(-3) M and by Ca2+ removal. These results indicate that pentobarbital and thiopental essentially produce a similar interference with Ca2+ influx inhibiting the contractile responses induced by the three vasoactive agents and the exocytotic NA release evoked by K+.