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At least 307 records · Page 17Linked to original sources
PubMed2000

Pulse oral versus pulse intraperitoneal calcitriol: a comparison of efficacy in the treatment of hyperparathyroidism and renal osteodystrophy in peritoneal dialysis patients.

Controversy exists among various studies in regard to the efficacy of oral (p.o.) versus parenteral calcitriol. Some studies suggest that intravenous (i.v.) calcitriol is superior to p.o. calcitriol for treating renal osteodystrophy in hemodialysis patients; others suggest that these routes of administration are equivalent. To our knowledge, no large, prospective, randomized study compares intraperitoneal (i.p.) to p.o. calcitriol in adult peritoneal dialysis patients. We conducted a prospective randomized study in 76 patients (38 on i.p. calcitriol and 38 on p.o. calcitriol), whom we followed for 48 months. Of the 76 patients, 34 (18 in the i.p. group and 16 in the p.o. group) completed the 48-month study period. Calcitriol dosing was similar in both groups (3-6 micrograms per week in three divided doses). Dose adjustments were made depending on levels of parathyroid hormone (PTH), serum calcium, phosphorus, and calcitriol. No significant difference was seen between the groups in regard to age, sex, race, body mass index, dialysis duration, or cause of ESRD. Neither was any difference in the incidence of peritonitis seen between the groups. In the first 3-6 months, PTH decreased equivalently in both groups. The PTH level remained suppressed in the i.p. group throughout the remainder of the study, but, in the p.o. group, PTH returned to its pretreatment level after 3-6 months. Mean serum calcium was not different in the two groups. In the p.o. group, a considerably higher mean follow-up phosphorus level (6.8 +/- 2.3 mg/dL versus 4.7 +/- 1.4 mg/dL, p = 0.008), PTH level (384 +/- 146 pg/mL versus 162 +/- 64 pg/mL; p = 0.005), and alkaline phosphatase level (178 +/- 37 IU/L versus 72 +/- 21 IU/L, p = 0.02) were seen as compared to the i.p. group. In the i.p. group, resolution of osteodystrophy occurred in all patients at the end of the study; in the p.o. group, 5 patients maintained or developed osteodystrophy by the end of the study (p = 0.016). We conclude that i.p. calcitriol is more effective than pulse p.o. calcitriol in lowering PTH and alkaline phosphatase levels and in resolving renal osteodystrophy, and that i.p. calcitriol is associated with a lower incidence of hyperphosphatemia and elevated Ca x PO4 byproduct.

Administration, Oral↗
PubMed1979

The reaction of solvated electrons with cytosine, 5-methyl cytosine and 2'-deoxycytidine in squeous solution. The reaction of the electron adduct intermediates with water, p-nitroacetophenone and oxygen. A pulse spectroscopic and pulse conductometric study.

Using conductivity detection, pulse radiolysis experiments showed that solvent protonation of the electron adducts of cytosine, 5-methyl cytosine and 2'-deoxycytidine occurs with rate constants k greater than or equal to 2 x 10(4) M-1S-1. The protonated electron adducts transfer an electron to p-nitroactetophenone (PNAP) with rate constants ranging from 3.5 x 10(9) to 5.3 x 10(9) M-1S-1. The transfer is quantitative (G = 2.7), as shown by conductometric and spectroscopic measurements. In the presence of O2 no electron transfer to O2 takes place, implying that O2 adds to the protonated electron adduct radicals. No electron transfer from the H- and OH-adducts of the cytosine derivatives, either to PNAP or to O2, takes place near neutral pH. It is suggested that the differences in the reaction behaviour of the H-adduct radicals and the protonated electron adduct radicals towards PNAP can be accounted for if different radicals are formed by H-addition and protonation of the electron adduct. The H atoms most probably add to the C-5-C-6 double bonds, whereas the electron adducts are protonated at N-3 and/or 0-2.

Acetophenones↗
PubMed2003

Hair removal with long pulsed diode lasers: a comparison between two systems with different pulse structures.

BACKGROUND AND OBJECTIVES: The aim was to study hair removal efficacy, and possible side effects of two commercially available long pulsed diode lasers. The radiant exposure was selected to a value of 35 J/cm2, which is frequently used in the clinic in accordance with manufacturer's recommendations. STUDY DESIGN/MATERIALS AND METHODS: A prospective clinical study was performed on twenty-nine patients with hair color ranging from light brown to black on the upper lip. One half of the upper lip was randomly selected for treatment with the MedioStar laser; the contralateral half of the lip was treated with the LightSheer laser. Three treatments were performed at 6-8 week intervals. Percent hair reduction and acute- and long-term side effects were evaluated after treatment. RESULTS: The average hair reductions 6 months after the first treatment were 49% with the MedioStar laser and 48% with the LightSheer laser. No scarring or pigmentary change of the skin was observed after any of the treatments with either laser. However, differences in acute side effects such as degree of erythema and burned hairs were observed. CONCLUSIONS: No statistically significant differences in hair removal efficacy were observed. These results agree with mathematical modeling, which also offers a method to estimate hair removal efficacy and adverse effects for a range of hair characteristics and laser parameters.

Adult↗
PubMed2005

Treatment of port wine stains with photodynamic therapy, using pulsed dye laser as a light source, compared with pulsed dye laser alone: a pilot study.

BACKGROUND AND OBJECTIVES: Laser-induced photo thermal damage has been combined with photodynamic therapy (PDT) using a systemic photosensitiser to treat vascular lesions. The efficacy of PDT using systemic 5-aminolaevulinic acid (5-ALA) as the photosensitiser and pulsed dye laser (PDL) as the light source in port wine stains (PWS) is unknown. STUDY DESIGNS/MATERIALS AND METHODS: We conducted an internally controlled pilot study comparing the efficacy of PDT using PDL as a light source, to PDL alone in the treatment of PWS. RESULTS: The PWS improved slightly in all patients but no significant difference was found between the three treatment arms in terms of lesional lightening or incidence and severity of side effects. CONCLUSIONS: There was no evidence of increased efficacy of PDT using PDL as a light source compared to PDL alone. There was also no significant difference in adverse events. Further studies using different treatment regimens over longer periods of time may be warranted.

Adult↗
PubMed1993

Transthoracic defibrillation: effect of dual-pathway sequential pulse shocks and single-pathway biphasic pulse shocks in a canine model.

To determine whether dual-pathway sequential shocks and single-pathway biphasic shocks improved the efficacy of transthoracic defibrillation, we delivered single or sequential truncated waveform shocks of variable duration, voltage, and direction (polarity) to three groups of closed-chest dogs. Dual-pathway sequential shocks were assessed in group 1 (eight animals), biphasic shocks with a single pathway were compared in 11 dogs (group 2), and the effect of varying the duration of the biphasic shocks was assessed in group 3 (four animals). There was no improvement in success rates of the intervention shocks compared with a standard single "control" shock at any energy level. In this experimental model unidirectional or biphasic sequential shocks given over single or dual pathways were not superior to standard single-pulse transthoracic defibrillation.

Analysis of Variance↗
PubMed1986

Neural analysis of temporally patterned sounds in the frog's thalamus: processing of pulse duration and pulse repetition rate.

We conducted a single unit study of auditory neurons in the central thalamic nucleus of the northern leopard frog. These cells, unlike those of the posterior thalamic nucleus (J. Comp. Physiol., 150 (1983) 333-344), were broadly tuned and sensitive to one or more temporal features (pulse duration and repetition rate) of complex sound signals. When compared with previous studies, these results suggest that temporal and spectral information may be processed separately by distinct populations of neurons within the frog's thalamus.

Acoustic Stimulation↗
PubMed2005

Comparative study of aminolevulic acid photodynamic therapy plus pulsed dye laser versus pulsed dye laser alone in treatment of viral warts.

OBJECTIVE AND BACKGROUND: A number of scientific publications describe the removal of viral warts using photoselective laser destruction with pulsed dye laser (PDL) or photodynamic therapy (PDT). Although both methods represent an enormous improvement in therapy, the results are not sufficiently consistent to consider these methods as the "gold standard" for therapy. METHODS: With a view to further improvement we combined a photoselective dye laser (595 nm, 20 J.cm(-2)) with photodynamic therapy using aminolevulic acid. The results of this method were compared against traditional laser photodestruction (of identical physical parameters) and against traditional photodynamic therapy (of similar parameters). RESULTS: After combined therapy (PDT + PDL) of 86 warts in 24 patients, 100% were cured, with an average of 1.96 therapeutic sessions. Therapy with PDT alone failed in 3 of 76 warts even after 5 sessions (96%), with an average of 2.54 therapeutic sessions. Therapy with PDL alone failed in 21 of 112 warts even after 5 sessions, with an average of 3.34 therapeutic sessions. CONCLUSIONS: All three therapeutic methods are able to cure infectious warts with high probability (>80%). However, a combination of PDT and PDL is the most effective and the most favored therapy. If other investigators also confirm results near or equal to 100% success, this therapy could become a treatment of choice for this indication.

Aminolevulinic Acid↗
PubMed2003

Influence of L-nitro-arginine methyl ester, acetylcholine, and adenosine on mean blood pressure, pulse pressure, and pulse pressure amplification in rats.

The blood pressure pattern in spontaneously hypertensive rats (SHRs) involves three main characteristics: increase in mean blood pressure (MBP); increase in thoracic aorta (proximal) and iliac (distal) pulse pressure (PP); disappearance of the normal PP amplification between the proximal and the distal arteries. Whether pharmacologic agents may reduce MBP with different or even opposite effects regarding PP and PP amplification has been poorly investigated. In SHRs and Wistar-Kyoto (WKY) anesthetized rats, the NO inhibitor l-nitro-arginine methyl ester (l-NAME) was infused at the dosage of 1 mg/kg for 30 min. Before and after infusion, 7 microg/kg/min acetylcholine (Ach) and 200 mg/kg adenosine (Ado) were perfused for 4 min. Proximal and distal intra-arterial BP was monitored throughout the procedure. In both WKYs and SHRs, l-NAME increased proximal and distal systolic (SBP), diastolic (DBP), and MBP but not PP. Before l-NAME, SBP, DBP, and MBP were significantly reduced by Ado and Ach. After l-NAME, such blood pressure reductions were abolished with Ach but not Ado. In both strains, the proximal and distal PP, when expressed in percent reduction of MBP, were significantly higher under Ado than under Ach. The Ado but not Ach changed PP amplification, causing a reduction in WKYs and an increase in SHRs independent of l-NAME. Vasodilating agents may reduce MBP with significantly different effects on PP. The Ado alters PP amplification, an effect not obtained with the nitric oxide endothelium-dependent vasorelaxing agent Ach. Tail SBP measurements cannot predict such dissociated changes.

Acetylcholine↗
PubMed2006

Comparison of the effects of pulsed dye laser, pulsed dye laser + salicylic acid, and clobetasole propionate + salicylic acid on psoriatic plaques.

BACKGROUND: Studies show that pulsed dye laser (PDL) has some clinical benefits on psoriasis with a low clearance rate. In addition, it has been suggested that applying keratolytics before treatment might be helpful in PDL therapy. Topical corticosteroids remain the most commonly prescribed agents for psoriasis. OBJECTIVE: This study was designed to compare the efficacy of the PDL treatment with that of PDL treatment after salicylic acid on psoriatic plaques. The other goal of this study was to compare the efficacy of the PDL treatment with that of clobetasol propionate treatment. METHODS: Twenty-two patients with chronic, stable psoriatic plaques that involved less than 20% of their body were included in the study. Three similar-appearing psoriasis plaques in these patients were selected. Whereas the first plaque received only PDL, the second plaque received PDL after salicylic acid, and the third plaque received clobetasol propionate ointment and salicylic acid. Evaluation of the study plaques was carried out by the modified Psoriasis Area and Severity Index (mPASI) score and by measuring the area of the plaques. RESULTS: Of the 21 patients, 19 completed the study. Although the decrease in mPASI scores was determined to be maximum for clobetasol propionate + salicylic acid-treated plaques and minimum for only PDL-treated plaques, the decrease was statistically significant in all groups when compared with baseline (p < .003). At the 3- and 6-week evaluations, there was a statistically significant difference between clobetasol propionate + salicylic acid-treated plaques and the two PDL-treated plaques (p < .003); however, the difference observed at the 9-, 12-, and 15-week evaluations was statistically significant only between clobetasol propionate + salicylic acid-treated plaques and PDL-treated plaques (p < .003). When the baseline and 15-week evaluations were compared, there was no statistically significant increase in the mean lesion areas of clobetasol propionate + salicylic acid-treated psoriatic plaques (p > .003), but there was a statistically significant increase in the mean lesion areas of two PDL-treated psoriatic plaques (p < .003). CONCLUSION: The results of this study showed that the effect of PDL could be increased when salicylic acid was added to treatment, although there was no statistically significant difference between both treatment protocols. However, clobetasol propionate + salicylic acid treatment is more effective than both PDL and PDL + salicylic acid treatment.

Adult↗
PubMed2006

Verruca vulgaris: pulsed dye laser therapy compared with salicylic acid + pulsed dye laser therapy.

BACKGROUND: In recent years, lasers have been used in verruca therapy and some successful results have been obtained in some types of verruca. In some of these laser studies, peeling processes have been used to increase penetration. OBJECTIVE: This study aimed to compare the effects of pulsed dye laser (PDL) therapy with the effects of PDL therapy following salicylic acid (SA) application. The purpose of the SA application is to increase the laser penetration by decreasing the hyperkeratosis of verruca vulgaris. METHODS: This controlled study included 66 lesions from 19 patients enrolled in the study. PDL was applied to 33 lesions following 30% SA application twice a day for 5 days, and the remaining 33 lesions underwent PDL therapy. PDL was administered in both groups at 4-week intervals varying from one to five sessions. In the comparison of these two groups, the changes in verruca dimensions were recorded in width x length x height (mm3), and the results of the therapy were evaluated statistically. RESULTS: In both PDL and SA + PDL groups, the regressions observed in the size of the lesions were statistically significant at the end of the fifth session compared with those observed at the onset of the therapy (P < 0.05). At the end of the fifth session, the difference between the two groups was not statistically significant (P = 0.451); however, the clearance rate in the SA + PDL group was more statistically significant than that in the PDL group after the second session (P = 0.049). The complete clearance rate in the SA + PDL group was 54.6% after the second session, but 66.4% in the PDL group only after the fifth session. Complete clearance in the SA + PDL group was observed after 2.2 sessions, and in the PDL group after 3.1 sessions (P < 0.05). CONCLUSIONS: Although there was no difference between the clearance rate of the SA + PDL group and that of the PDL group after the fifth session, adding SA to PDL decreased the number of sessions to a large extent.

Adolescent↗
PubMed1998

A practical review of laser-assisted hair removal using the Q-switched Nd:YAG, long-pulsed ruby, and long-pulsed alexandrite lasers.

BACKGROUND: The recent development of numerous laser-assisted hair removal techniques has produced confusion in the field of cutaneous laser surgery. OBJECTIVES: A systematic review of the hair removal laser systems currently available is attempted. Appropriate patient selection, treatment protocols, and discussion of each system's advantages, disadvantages, and complications is provided. CONCLUSIONS: Techniques involving the use of selective Q-switched Nd:YAG and long-pulsed alexandrite and ruby laser systems provide a significant delay in hair growth. With further technologic advances and understanding of proper treatment parameters and intervals, it is expected that permanent hair removal may eventually be possible.

Equipment Design↗
PubMed2006

Split-face comparison of photodynamic therapy with 5-aminolevulinic acid and intense pulsed light versus intense pulsed light alone for photodamage.

BACKGROUND: Photodynamic therapy (PDT) with a 5-aminolevulinic acid (ALA) photosensitizing agent and a variety of lasers and light sources has been shown to enhance the treatment of photodamaged skin and its associated actinic keratoses (AKs). The efficacy of short-contact, full-face ALA by PDT in photorejuvenation has also been demonstrated. OBJECTIVE: To evaluate short-contact (30 to 60 min) ALA-PDT with intense pulsed light (IPL) activation by comparing ALA-PDT-IPL with IPL alone. METHODS Sixteen patients were enrolled in a split-face study. One side of each patient's face received ALA-PDT-IPL and the other side received IPL alone. Three treatments were given at 1-month intervals, and follow-up visits occurred at 1 and 3 months after the final treatment. RESULTS: Thirteen patients completed the trial. Three months after the final treatment, improvement was greater in the ALA-PDT-IPL side than in IPL-alone side for all facets of photodamage-crow's feet appearance (55 vs 29.5%), tactile skin roughness (55 vs 29.5%), mottled hyperpigmentation (60.3 vs 37.2%), and telangectasias (84.6 vs 53.8%). The clearance rate of AK lesions was also higher (78 vs 53.6%). CONCLUSION: Short-contact ALA-PDT-IPL brings about greater improvement in photodamaged skin and greater clearance of AK lesions than IPL alone, further confirming the usefulness of ALA-PDT in photorejuvenation.

Adult↗
PubMed1993

A pulsed laser and pulse radiolysis study of amphiphilic chlorophyll derivatives with PDT activity toward malignant melanoma.

Two amphiphilic derivatives of chlorophyll, which have high potential as photodynamic therapy sensitizers for malignant melanoma have been investigated by a combination of laser flash photolysis and pulse radiolysis. It is shown that direct excitation of monomeric forms of these molecules in both hydrophilic and hydrophobic environments produces significant yields of the corresponding triplet states, which have been characterized in terms of spectral and kinetic parameters. In both environments, scavenging of the triplets by oxygen produces singlet oxygen, O2(1 delta g), with essentially unit efficiency as evidenced by time-resolved IR luminescence measurements.

Chlorophyll↗
PubMed2002

Frequency-dependent shift from paired-pulse facilitation to paired-pulse depression at unitary CA3-CA3 synapses in the rat hippocampus.

Paired recordings between CA3 interconnected pyramidal neurons were used to study the properties of short-term depression occurring in these synapses under different frequencies of presynaptic firing (n = 22). In stationary conditions (0.05-0.067 Hz) pairs of presynaptic action potentials (50 ms apart) evoked EPSCs whose amplitude fluctuated from trial to trial with occasional response failures. In 15/20 cells, paired-pulse ratio (PPR) was characterized by facilitation (PPF) while in the remaining five by depression (PPD). Increasing stimulation frequency from 0.05-0.067 Hz to 0.1-1 Hz induced low frequency depression (LFD) of EPSC amplitude with a gradual increase in the failure rate. Overall, 9/12 cells at 1 Hz became almost "silent". In six cells in which the firing rate was sequentially shifted from 0.05 to 0.1 and 1 Hz, changes in synaptic efficacy were so strong that PPR shifted from PPF to PPD. The time course of depression of EPSC1 could be fitted with single exponentials with time constants of 98 and 36 s at 0.1 and 1 Hz, respectively. In line with the inversion of PPR at 1 Hz, the time course of depression of EPSC2 was faster than EPSC1 (7 s). Recovery from depression could be obtained by lowering the frequency of stimulation to 0.025 Hz. These results could be explained by a model that takes into account two distinct release processes, one dependent on the residual calcium and the other on the size of the readily releasable pool of vesicles.

Animals↗
PubMed2004

Terahertz-pulse generation by photoionization of air with laser pulses composed of both fundamental and second-harmonic waves.

Intense radiation in the terahertz (THz) frequency range can be generated by focusing of an ultrashort laser pulse composed of both a fundamental wave and its second-harmonic field into air, as reported previously by Cook et al. [Opt. Lett. 25, 1210 (2000)]. We identify a threshold for THz generation that proves that generation of a plasma is required and that the nonlinearity of air is insufficient to explain our measurements. An additional THz field component generated in the type I beta-barium borate crystal used for second-harmonic generation has to be considered if one is to avoid misinterpretation of this kind of experiment. We conclude with a comparison that shows that the plasma emitter is competitive with other state-of-the-art THz emitters.

Journal Article↗
PubMed2004

400-photon-per-pulse ultrashort pulse autocorrelation measurement with aperiodically poled lithium niobate waveguides at 1.55 microm.

We demonstrate ultrasensitive intensity autocorrelation measurements of subpicosecond optical pulses in the telecommunication band by using aperiodically poled lithium niobate (A-PPLN) waveguides. The tightly confined optical beam in the waveguides and the chirped poling period facilitate simultaneous high second-harmonic generation (SHG) efficiency and broad phase-matching (PM) bandwidth. The resulting measurement sensitivity is 3.2 x 10(-7) mW2, approximately 500 times better than the previous record for intensity autocorrelations. We also show that chirped A-PPLN waveguides retain nearly the same SHG efficiency as the unchirped guide as long as the PM bandwidth is not significantly broader than the input spectrum.

Journal Article↗