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PubMed1976

The effects of lanthanum and thulium on the mechanical responses of rat vas deferens.

1. The contractile responses of rat vas deferens to noradrenaline and K+ are composed of phasic and tonic components both of which are dependent upon the concentration of extracellular Ca2+. 2. Lanthanum, La3+, and thulium ions, Tm3+, inhibited the noradrenaline and K+ induced responses, complete inhibition being obtained at approximately 10(-3) M-Ln3+. 3. La3+ and Tm3+ were equally effective in inhibiting noradrenaline and K+ responses. The phasic and tonic components of the noradrenaline response were equally sensitive to lanthanide cations, Ln3+, but the phasic component of the K+ response was more sensitive than the tonic component. 4. 170Tm binding did not show any saturable component over the concentration range in which inhibition of the pharmacological response was obtained. 5. It is suggested that the actions of Ln3+ in the rat vas deferens are mediated through some kind of membrane stabilization rather than via a specific Ca2+ binding site concerned with excitation-contraction coupling, the mechanism previously postulated for the Ln3+ action in guinea-pig ileal longitudinal muscle.

Animals↗
PubMed1981

Thulium binding to the pancreatic beta-cell membrane.

Radioactive thulium (171Tm) was used to probe cation-binding sites in the plasma membrane of beta-cell-rich pancreatic islets microdissected from noninbred ob/ob mice. Temporal studies revealed that 171Tm uptake was rapid, reaching isotopic equilibrium by 60 min. Analysis of the concentration dependence of 171Tm uptake revealed at least two components. At low 171Tm concentrations (0.003--0.18 micrometer), there was a saturable low capacity component, capable of accommodating less than 20 mumol/kg dry weight. At higher 171Tm concentrations (1.0--500 micrometers), a nonsaturable high capacity component capable of binding more than 100 mmol/kg dry weight was observed. 171Tm taken up at 0.18 micrometer exhibited a high degree of mobility. The uptake of 171Tm at this concentration was increased by incubation with chlorpromazine at concentrations known to increase the permeability of the beta-cell plasma membrane. At 0.18 micrometer, exposure to 20 mM D-glucose reduced 171Tm uptake compared with that in islets incubated in the absence of sugar or in the presence of sugars which lack stimulatory effects on insulin release. Such an effect was not observed at 125 micrometers, and none of the sugars influenced the 171Tm uptake of the exocrine pancreas. These data raise the possibility that cation-binding sites in the beta-cell plasma membrane are of physiological significance in the regulation of insulin secretion.

Animals↗
PubMed2005

[Thulium laser resection of prostate-tangerine technique in treatment of benign prostate hyperplasia].

OBJECTIVE: To evaluate the safety and efficacy of thulium laser resection of prostate-tangerine technique (TmLRP) in treatment of benign prostate hyperplasia (BPH). METHODS: Thirty BPH patients, aged 74 (61-83), with a mean prostate volume of 58 ml, average international prostate symptom score (IPSS) of 19, and average maximum urinary flow (Q(max)) of 8.0 ml/s underwent TmLRP using 50 watt, 2.01 microm Tm laser. The values of hematocrit, serum sodium, potassium, and chlorine concentrations, hemoglobin, Q(max), and IPSS before and 1 and 3 months after TmLRP were compared. RESULTS: The mean operating time was 56 minutes. No significant bleeding was found during operation. Post-operative bladder irrigation was no necessary. The urethral catheter was indwelled for 1-3 days post-operatively. There were not significant differences in values of hematocrit, serum sodium, potassium, and chlorine concentrations, and hemoglobin before and 1-3 months after the operation. One month after the operation, the Q(max) was 23.1 ml/s and IPSS was 7.9, and 3 months after the operation the was 24.7 ml/s and the IPSS was 7.1. By the end of 3-month follow-up no new cases of impotence and retrograde ejaculation had been found. CONCLUSION: TmLRP is a safe and efficient procedure in treatment of BPH.

Aged↗
PubMed1994

[Thulium-holmium-chromium-doped YAG laser sclerostomy ab externo in uncontrollable glaucoma].

Laser sclerostomy ab externo, using thulium-holmium-chromium-doped YAG laser was performed in 40 eyes with refractory glaucoma. Preoperative intraocular pressure (IOP) ranged from 21 to 50 mmHg (mean +/- SD: 33 +/- 18.6) with maximum tolerable medications. In all cases, a full-thickness sclerostomy was performed and subsequently a filtering bleb was formed. Total energy levels to produce the sclerostomy ranged from 0.2 J to 12.9 J (3.9 +/- 2.4). Follow-up periods varied from 3 to 18 (9 +/- 4) months. IOP control rate calculated by a life-table method at 6 and 12 months after surgery was 54% and 46%, respectively. IOP for successful eyes ranged from 0 to 18 mmHg (12.3 +/- 2.4). As complications, corneal fold formation (all eyes), choroidal detachment (12 eyes), hyphema (10 eyes), and iris incarceration in the sclerostomy site (4 eyes) were found. Astigmatism caused by corneal fold formation disappeared spontaneously within 3 months. Iris incarceration causing IOP elevation was repaired by Nd-YAG laser treatment and IOP control was obtained in 2 of 4 eyes. No other complications were observed.

Chromium↗
PubMed2003

Structure and reactivity of homoleptic samarium(II) and thulium(II) phospholyl complexes.

Potassium 2,5-di-tert-butyl-3,4-dimethylphospholide K(dtp) (9) was synthesised in 45 % yield from commercially available starting materials by using zirconacyclopentadiene chemistry. Reaction of the K salt of this bulky anion and of the previously described potassium 2,5-bis(trimethylsilyl)-3,4-dimethylphospholide K(dsp) (8) with SmI(2) in diethyl ether afforded the homoleptic samarium(II) complexes 7 and 6, respectively, whose solid-state structures, [[Sm(dtp)(2)](2)] (7 a) and [[Sm(dsp)(2)](2)] (6 a), are dimeric owing to coordination of the phosphorus lone pairs to samarium, as shown by X-ray crystallography. Reaction of 8 with TmI(2) in diethyl ether afforded [Tm(dsp)(2)(Et(2)O)], which could not be desolvated without decomposition. In contrast, the coordinated ether group of the solvate [Tm(dtp)(2)(Et(2)O)], obtained from 9 and TmI(2), could easily be removed by evaporation of the solvent and extraction with pentane at room temperature, and the monomer [Tm(dtp)(2)] (5) could be isolated and was characterised by X-ray crystallography. Presumably, steric crowding in 5 is too high for dimerisation to occur. Compound 5, the first Tm(II) homoleptic sandwich complex, is remarkably stable at room temperature in solution and did not noticeably react with nitrogen, in sharp contrast with other thulium(II) species. As expected, 5, 6 and 7 all reacted with azobenzene to give the trivalent complexes [Tm(dtp)(2)(N(2)Ph(2))] (13), [Sm(dsp)(2)(N(2)Ph(2))], (14) and [Sm(dtp)(2)(N(2)Ph(2))] (15), respectively; 13 and 14 were characterised by X-ray crystallography. Complex 5 immediately reacted with triphenylphosphane sulfide at room temperature to give [[Tm(dtp)(2)](2)(mu-S)] (16), which was characterised by X-ray crystallography, whereas samarium(II) complexes 6 and 7 did not noticeably react with Ph(3)PS over 24 h under the same conditions.

Journal Article↗
PubMed1989

Welding of gallbladder tissue with a pulsed 2.15 microns thulium-holmium-chromium:YAG laser.

Percutaneous endoscopic approaches to cholelithiasis would be facilitated by methods for welding gallbladder tissues. We evaluated the bursting pressure and histologic appearance of canine gallbladder tissue welded with a thulium-holmium-chromium:YAG (THC:YAG) laser producing a 2.15 microns pulsed output. The tissue absorption characteristics at this wavelength as well as the pulsed nature of the output permit tissue welding with limited collateral thermal damage. The THC:YAG is compatible with a flexible fiberoptic delivery system. Bursting strengths of the welded junctions averaged 42 mm Hg, which is above physiologically encountered pressures. Histologic sections of the bonded tissues revealed tissue fusion and limited thermal injury to the surrounding tissue. We feel that THC:YAG laser welding may be a useful technique in the clinical development of percutaneous endoscopic biliary surgery.

Animals↗
PubMed2006

Non-invasive temperature imaging with thulium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetic acid (TmDOTMA-).

Non-invasive thermometry using hyperfine-shifted MR signals from paramagnetic lanthanide complexes has attracted attention recently because the chemical shifts of these complexes are many times more sensitive to temperature than the water 1H signal. Among all the lanthanide complexes examined thus far, thulium tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (TmDOTMA-) appears to be the most suitable for MR thermometry. In this paper, the feasibility of imaging the methyl 1H signal from TmDOTMA- using a frequency-selective radiofrequency excitation pulse and chemical shift-selective (CHESS) water suppression is demonstrated. A temperature imaging method using a phase-sensitive spin-echo imaging sequence was validated in phantom experiments. A comparison of regional temperature changes measured with fiber-optic probes and the temperatures calculated from the phase shift near each probe showed that the accuracy of imaging the temperature with TmDOTMA- is at least 0.1-0.2 degrees C. The feasibility of imaging temperature changes in an intact rat at 0.5-0.6 mmol/kg dose in only a few minutes is demonstrated. Similar to commonly used MRI contrast agents, the lanthanide complex does not cross the blood-brain barrier. TmDOTMA- may prove useful for temperature imaging in many biomedical applications but further studies relating to acceptable dose and signal-to-noise ratio are necessary before clinical applications.

Animals↗
PubMed2001

Separation of carrier-free 181Re produced in 16O-irradiated thulium target.

Heavy ion activation of natural Tm2O3 with 90 MeV 16O beam results in the formation of carrier-free short-lived 181Ir and 181Os which ultimately decay out to 181Re in the matrix. The liquid cation exchanger, HDEHP, has effectively been utilized as an extractant for quantitative separation of bulk thulium target matrix from carrier-free rhenium radionuclide.

Journal Article↗
PubMed2000

Observation of anti-stokes fluorescence cooling in thulium-doped glass

We report the first observation of anti-Stokes fluorescence cooling in a thulium-doped solid with pump excitation at 1.82 &mgr;m<lambda<1.97 &mgr;m. At a pump wavelength of 1.9 &mgr;m and incident average power of approximately 3 W, a Tm3+:ZBLANP ( ZrF4-BaF2-LaF3-AlF3-NaF-PbF2) sample cooled to -1.2 degrees C from room temperature for a single pass of the pump beam. This corresponds to an absorbed pump power of approximately 40 mW and a peak temperature change per absorbed power of approximately -30 degrees C/W from room temperature.

Journal Article↗
PubMed2003

Low-pump-power, short-fiber copropagating dual-pumped (800 and 1050 nm) thulium-doped fiber amplifier.

Using optical frequency-domain reflectometry to reveal the gain distribution and allow us to optimize a thulium-doped fiber amplifier, we have demonstrated 18-dB gain by employing only 5 m of a 2000-parts-in-10(6)-Tm-doped fiber pumped with 145 mW of power at dual wavelengths of 800 and 1050 nm. The role of the 800-nm pump, which by itself does not permit population inversion, was clearly observed experimentally.

Journal Article↗
PubMed2004

Modeling the distributed gain of single--(1050 or 1410 nm) and dual-wavelength--(800 + 1050 nm or 800 + 1410 nm) pumped thulium-doped fiber amplifiers.

The distributed gain of single- and dual-wavelength-pumped thulium-doped fiber amplifiers is modeled. The excellent agreement between the model and coherent optical frequency domain reflectometry measurements enables us to estimate intrinsic loss, branching ratios of fluorescence originating from the 3H4 level, and cross sections of upconversion pumping at 1050 and 1410 nm for the Tm3+ ions in the fiber. With the branching ratios obtained it is possible to describe induced signal absorption when pumping at 800 nm.

Journal Article↗
PubMed1997

[X-ray fluorescence spectrometrlc determination of nine heavy rare earth elements in the enriched mixture of thulium oxide, ytterbium oxide and lutecium oxide by asming thin film technique].

A method for the determination of nine heavy rare earth elements in the enriched mixture of thulium oxide ytterbium oxide and lutecium oxide by XRF method has been studied in this poper. The samples were prepared by ashing thin film. This method is characterized as it is low cost, economic and simple in standards preparation, and standards can be easily preserved. The accuracy and precision of the results were satisfactory for the demands of prodnction.

English Abstract↗
PubMed1991

Alternative lasers for endoscopic surgery: comparison of pulsed thulium-holmium-chromium:YAG with continuous-wave neodymium:YAG laser for ablation of colonic mucosa.

Precise and controllable tissue vaporization is essential for minimizing risk in removal of sessile polyps from the lumen of thin walled gastrointestinal organs such as the colon. We compared the ablative efficiency on canine colonic mucosa of the THC:YAG laser with the clinically employed cw Nd:YAG laser. Fresh canine colon was treated with a progressive dose schedule using each laser at several energy/power densities. Ablation depth was measured on fresh tissue and thermal (non-ablation or coagulative) damage examined histologically. The THC:YAG ablation rates were 13.7 +/- 0.8 and 10.2 +/- 0.4 microns/J at 55 and 85 J/cm2, respectively. The Nd:YAG laser generated 3.7 +/- 0.3, 2.8 +/- 0.1, and 3.6 +/- 0.2 microns/J at 4,460, 5,095, and 5,730 W/cm2, respectively. There was a significant (P less than 0.001) difference among the THC:YAG ablation rates and between the THC:YAG and Nd:YAG ablation rates (ANOVA). The THC:YAG laser craters had significantly less collateral thermal damage than Nd:YAG. The pulsed THC:YAG laser should have an important clinical role since its use could reduce the risk of perforation in endoscopic laser procedures such as the removal of sessile polyps.

Aluminum Silicates↗