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At least 19 recordsLinked to original sources
PubMed2026

Topical Carboxytherapy as an Adjunct to Skin Recovery Post-CO2 Laser Fractional Resurfacing.

BACKGROUND: Topical carboxytherapy, a transcutaneous carbon dioxide (CO2) delivery system, may support skin repair and regeneration, yet its role as an adjunct to fractional laser treatment remains underexplored. OBJECTIVE: To investigate the effectiveness and safety of topical CO2 mask (CO2Lift® Carboxy Gel, Lumisque Skincare) in supporting skin recovery and improving clinical outcomes following fractional CO2 laser resurfacing. METHOD: This 12-week randomized, placebo-controlled trial evaluated mild-to-moderate photoaging (n=6 females only). Participants received either topical carboxytherapy (n=4) or standard care (n=2). Assessments included VISIA-CR imaging, biophysical measurements, investigator ratings, and paired (baseline and 4-week) skin biopsies. RESULTS: Topical carboxytherapy accelerated recovery and was well-tolerated, with no major adverse events. VISIA-CR imaging showed accelerated erythema resolution, transepidermal water loss normalized more rapidly, and pH remained stable. Skin histology at week 4 revealed epidermal thickening and rete ridge formation with topical carboxytherapy vs placebo. Investigator ratings demonstrated significantly improved healing, global assessment, and global aesthetic improvement scale scores, with trends toward improvement in photodamage, rhytides, and pigmentation. CONCLUSION: Adjunctive topical carboxytherapy after fractional CO2 resurfacing accelerated healing, improved barrier recovery, and overall aesthetic outcomes. Larger studies are needed to confirm these findings.

Humans↗
PubMed2026

Comparison of a 755-nm picosecond laser and a 1565-nm nonablative fractional laser for the treatment of atrophic acne scars: a 20-week prospective, randomized, split-face clinical study.

To compare the efficacy and safety of a 755-nm picosecond laser with a diffractive lens array (P-DLA) and a 1565-nm nonablative fractional laser (NAFL) for the treatment of atrophic acne scars. Twenty-seven patients with atrophic acne scars underwent three sessions of randomized split-face treatment with P-DLA and NAFL at 4-week intervals. Patients were followed up at 1, 2, and 3 months after the final treatment. Efficacy was assessed using the &#xc9;chelle d'&#xc9;valuation Clinique des Cicatrices d'Acn&#xe9; (ECCA) grading scale, the Investigator's Global Assessment (IGA) score, patients' self-rated improvement, and overall satisfaction. Treatment-related adverse reactions were recorded daily by patients until resolution. Both modalities demonstrated significant improvements in scar appearance based on ECCA score, IGA score, and patients' self-rated improvement (P&#x2009;<&#x2009;0.001). No statistically significant differences in efficacy were observed between the two treatments. However, the P-DLA group showed higher patient satisfaction (P&#x2009;=&#x2009;0.035) and a more favorable safety profile, including shorter durations of erythema and edema and the absence of crusting. Both P-DLA and NAFL were effective and safe for the treatment of atrophic acne scars, with similar efficacy. P-DLA offered better tolerability.

Humans↗
PubMed2026

Fractional laser therapy versus microneedling for non-acne scars and scar-like dermal fibrotic lesions.

BACKGROUND: Scarring caused by trauma, burns, surgery, and other dermal fibrotic conditions can lead to functional limitation and cosmetic distress. The comparative effectiveness of fractional laser therapy and microneedling for non-acne scars remains uncertain. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials comparing fractional laser therapy with microneedling for non-acne scars and scar-like dermal fibrotic lesions. Following a PROSPERO-registered protocol and PRISMA guidelines, we searched PubMed, EMBASE, Web of Science, Cochrane Library, and CNKI from inception to May 2026 without language restrictions. Parallel-group and split-body randomized trials were eligible. Random-effects models were used to calculate standardized mean differences (SMDs) for continuous outcomes and odds ratios (ORs) for dichotomous outcomes. RESULTS: Nine randomized controlled trials were included. Fractional laser therapy showed a statistically significant advantage over microneedling in scar scores (SMD = -0.99, 95% CI [-1.83, -0.15], P&#x2009;=&#x2009;0.02) and collagen fiber regeneration (SMD = -2.14, 95% CI [-3.57, -0.72], P&#x2009;=&#x2009;0.03). No statistically significant differences were found between the two interventions for elastic fiber improvement, epidermal thickness, or adverse events. Subgroup analyses did not show clear or consistent significant differences according to laser type, including comparisons between traditional and non-traditional fractional lasers and between CO&#x2082; and non-CO&#x2082; fractional laser systems. Substantial heterogeneity was observed across several outcomes, indicating considerable between-study variability. CONCLUSION: Based on currently available randomized evidence, fractional laser therapy may provide superior improvement in overall scar severity and collagen fiber regeneration compared with microneedling for non-acne scars and scar-like dermal fibrotic lesions. However, no clear differences were observed for elastic fiber improvement, epidermal thickness, or adverse-event incidence. Given the substantial heterogeneity, limited sample sizes, and possible reporting bias, these findings should be interpreted cautiously. Further large, standardized trials with longer follow-up are needed.

Humans↗
PubMed1977

The molecular size and shape of liver glycogen.

The molecular-weight distribution of liver glycogen has been established from the analysis of sedimentation rates of fractions separated on sucrose density gradients and from the direct measurement of the diffusion coefficients of these fractions by laser-intensity-fluctuation spectroscopy. Hydrodynamic studies indicated that all fractions of glycogen of mol.wt.exceeding 25x10(6) had about 1.1 g of water per g of polysaccharide associated with them. The hydration and hydrodynamic behaviour of all fractions of mol.wt. exceeding 25x10(6) was similar, whereas smaller fractions behaved anomalously, indicating a substantially different overall structure.

Centrifugation, Density Gradient↗
PubMed1978

Neutralising effect of histone fractions from human leukocyte nuclei on heparin.

Histone fractions from human leukocyte nuclei can interact with heparin to form complexes measurable by means of laser nephelometry. Histone fractions have not all the same affinity to bound heparin and the lysinrich histone fraction cannot interact with heparin. The formation of histone/heparin complex depends not on the temperature between 20 degrees--37 degrees C or on the pH between 7--8.2. The precision of the method was estimated. The significance of the histones/heparin interactions for an assay method for control to the biological activity of heparin preparations and a possible biological role of these interactions in vivo was briefly discussed.

Cell Nucleus↗
PubMed1975

Laser Raman spectroscopic studies of ocular lens and its isolated protein fractions.

The water-soluble proteins of the bovine lens were separated on a column of Sephadex G-200 into five fractions designated as alpha-, beta1-, beta2-, and gamma-crystallin. Laser Raman scattering studies on these isolated proteins (both in the lyophilized state and in solution) and insoluble albuminoid reveal that they contain predominantly antiparallel pleated sheet structure in the main chains and that sulfhydryl groups are highly localized in gamma-crystallin. This light-scattering technique was also applied to probe the homogeneity of protein structure in the intact lens. The analysis of the scattered light selectively collected from various parts of the lens indicated that these proteins also exist in an antiparallel beta structure throughout the entire lens. However, the central (nucleus) and outer (cortex) portions have somewhat different amino acid composition. Based on the relative intensities of the lines at 624 (phenylalanine) and 644 cm-1 (tyrosine), it is concluded that the nuclear part has the highest concentration of gamma-crystallin and that the content of alpha-crystallin increases significantly from the nucleus to the cortex. By examining the Raman spectra in the 2582 cm-1 and the amide I and III regions, we have demonstrated that the sulfhydryl groups and the beta conformation of the lens proteins are unaffected in the conversion of transparent to totally opaque lens by heat denaturation at 100 degrees. This means that the opacification of a lens does not necessarily involve the oxidation of sulfhydrul groups or conformation changes.

Amides↗
PubMed1977

Picosecond laser study of fluorescence lifetimes in spinach chloroplast photosytem I and photosystem II preparations.

Fractions enriched in either Photosystem I or Photosystem II have been prepared from chloroplasts with digitonin. A more detailed analysis of the decay kinetics of fluorescence excited by a picosecond laser pulse has been possible compared to experiments with unfractionated systems. The Photosystem I fractions show a very short component (less than or equal to 100 ps) at room temperature which is apparently independent of pulse intensity over the range of photon densities used (5 - 10(13)--1 - 10(16) photons cm-2). The Photosystem II fraction has a short initial lifetime at room temperature which is strongly intensity-dependent approaching 500 ps at low photon densities, but decreasing to close to 150 ps at the highest photon densities. All of these room temperature decays appear to be non-exponential, and may possibly be fitted by at t1/2 expression, expected from a random diffusion of excitations via Förster energy transfer. On cooling to 77K, lifetimes of both Photosystem I and Photosytem II increase, the lengthening with Photosystem I being more striking. The Photosystem I decays become intensity dependent like the Photosystem II, and at the lowest photon densities decays which are more nearly exponential within the experimental error give initial lifetimes of about 2 ns. The non-exponential decays seen at high photon densities appear to fit a t1/2 expression.

Chloroplasts↗
PubMed1979

[Radioautographic study of a culture of fibroblasts after irradiation by a neodymium laser].

By means of radioautographic method, with 3H-thymidin application there were studied: mitotic activity, the number of DNA-synthesizing cells, growth fraction and population number of fibroblast culture irradiated with a single impulse of neodymium laser at energy density within 1 Dg/cm2--100 Dg/cm2. Under the influence of small doses of laser radiation (1--10 Dg/cm2) the number of dividing DNA-synthesizing cells increased, together with proliferative pool and the number of cells in the field of vision. At energy density of laser radiation equal to 50 Dg/cm2, and especially to 100 Dg/cm2 despite increased mitotic index and labelled cells index, registered during first hours of the effect, proliferative pool decreased and population growth rate lowered. These doses of laser radiation produced destruction of a rather large part of the cells in a monolayer.

Animals↗
PubMed1976

[Laser surgery of the vocal cord. An experimental study (author's transl)].

In animals the endolaryngeal application of laser rays of the Nd: YAG Laser MediLas (lambda = 1.06 mum) was tested under microsurgical conditions, the early and late alterations of the vocal cords caused by a dosage of 17 watt/mm2 fractioned over 7 sec were endoscopically observed and studied by light- and electronmicroscopy. A circumscribed vocal cord edema induced by laser entails no functional impairment whatsoever. Histologically the laser lesions can be interpreted as epithelial defect with a reactive inflammation of the adjacent connective tissue. A fundamental loss in substance cannot be realized. The superficial defect healed within 18 days; after 7 weeks the zone of regeneration and the undamaged part of the vocal cord could no longer be differentiated neither by light- nor by electronmicroscopy. Laser surgery has the special merit of permitting a touchless and bloodless operation. These experiences with the Nd: YAG Laser MediLas encourage us to use this procedure in clinical tests for the therapy of benignant squamous epithelium hyperplasia of vocal cords.

Animals↗
PubMed1975

Fluorescent kinetics of chlorophyll in photosystems I and II enriched fractions of spinach.

The fluorescent emission kinetics of spinach subchloroplast Photosystems I and II particles have been studied on a picosecond time scale. Using picosecond laser pulses and an optical Kerr gate, the fluorescent decay times are measured to be 60 plus or minus 10 ps, and 200 plus or minus 20 ps for Photosystems I and II, respectively. The quantum yields are calculated to be 0.004 for Photosystem I and 0.013 for Photosystem II. Theory of exciton energy transfer and trapping is applied for the determination of intermolecular potential energyin the photosystems.

Chlorophyll↗
PubMed1979

Dependence of the quantum efficiency for photolysis of carboxyhemoglobin on the degree of ligation.

A combined stopped flow-laser photolysis apparatus was used to measure the quantum efficiency for removal of carbon monoxide bound to human hemoglobin as a function of fractional CO saturation. This flow-flash technique allows the properties of partially liganded hemoglobin molecules, which are sparsely populated under equilibrium conditions, to be conveniently studied. Experiments performed at pH 7 and 20 degrees C both in the presence and absence of phosphates gave a similar dependence of quantum efficiency on fractional saturation. The observed quantum efficiency was 0.90 +/- 0.06 at 10% saturation and decreased to 0.47 +/- 0.02 as full saturation was approached. An allosteric model in which Hb(CO)1 has a quantum efficiency of 0.99 while other liganded species have quantum efficiencies of 0.47 was used to produce a good simulation of the results.

Carbon Monoxide↗
PubMed1976

The measurement of ocular transmittance and irradiation distribution in argon laser irradiated rabbit eyes.

The transmittance of the ocular media has been measured in vivo in rabbit eyes using an argon laser light source and microthermocouple sensor. The intensity profiles at the cornea and retina were measured with the thermocouple and the ratio of the power associated with the intensity profiles indicated the fraction of light power reaching the retina. Measurements from 10 rabbits indicated a transmittance coefficient of 0.85 for wavelengths between 488 and 514.5 nm.

Animals↗
PubMed1979

Micropreparation techniques in quantitative histochemistry - density gradient centrifugation, manual microdissection and laser microbeam preparation of tissue.

Each quantitative histochemical problem needs its specific method for tissue preparation. In this connection two of the most important preparation methods, density gradient centrifugation and microdissection of freeze-dried tissue slices, are described. Density gradient centrifugation is a very effective procedure for preparative separation of cell particles such as cell nuclei. The details of the preparation of glial and neuronal cell nuclei are described. The in vitro phosphorylation of histone in the chromatin in relation to age is given as a practical example of the quantitative histochemical application to a preparation of cell nuclei. Other techniques of tissue preparation are the manual tissue microdissection according to Lowry and the Laser microbeam preparation. Advantages and disadvantages of both methods are compared. It is shown, that the introduction of Laser microbeam dissection technique, as alternative to manual microdissection, add new dimensions to Lowry's ultramicrochemical methods. One has greater freedom in the choice of the sample size and the number of samples dissected from the same slice. Furthermore, the need for a well-trained person for the preparation is eliminated. The preparation is also considerably less time consuming and easier to perform than the manual free hand preparation. Two quantitative histochemical methods used for the investigation of microdissected tissue samples are described: the gas-chromatography-massfragmentography (GC/MS)-method for determination of transmitters and its metabolites as well as the enzymatic cycling technique of Lowry. The GC/MS-method is explained with an example of noradrenaline and dopamine determination. The enzymatic cycling technique is demonstrated in combination with the Oil-Well-Technique for determination of the NADP-cycle.

Cell Fractionation↗
PubMed1975

Picosecond detection of an intermediate in the photochemical reaction of bacterial photosynthesis.

Preparations of photosynthetic reaction centers from Rhodopseudomonas sphaeroides were excited with flashes lasting approximately 8 psec. Immediately after the excitation, there appeared a transient state which was characterized by new absorption bands near 500 and 680 nm, by a bleaching of bands near 540, 600, 760, and 870 nm, and by a blue shift of a band near 800 nm. The transient state decayed with an exponential decay time,t, of 246 plus or minus 16 psec after the flash. As the transient state decayed, the radical cation of the reaction center bacteriochlorophyll complex appeared. This indicates that the transient state is an intermediate in the photooxidation of the bacteriochlorophyll. The absorpiton spectrum of the transient state shows the state to be identical with a state (P-F) which has been detected previously in reaction centers that are prevented from completing the photooxidation, because of chemical reduction of the electron acceptor. Analysis of the spectrum suggests that the formation of P-F involves electron transfer from one bacteriochlorophyll molecule to another within the reaction center, or possibly from bacteriochlorophyll to the bacteriopheophytin of the complex. The initial absorbance changes after flash excitation also include a bleaching of an absorption band at 800 nm. The bleaching decays with tau approximately equal to 30 pse. The bleaching appers not to be a secondary effect, but rather to revael another early step in the primary photochemical reaction.

Bacteriochlorophylls↗
PubMed1979

Quantitative cytology of the positive region in flow sorted vaginal smears.

Fifty-one gynecologic specimens were collected from three women's hospitals and mailed in a prefixed status to our laboratory. The specimens were classified into a negative, a suspicious, a postradiation, and a positive group. After single cell dispersion the samples were stained for DNA and protein, analyzed, and sorted in the dual laser equipped Heidelberg flow analyzer sorter (HEIFAS). Particles with elevated DNA values (beyond 3.5 ploidy) and with intermediate protein values were sorted as the positive fraction directly on microscopic slides. After restaining according to Papanicolaou, they were re-evaluated cytologically and identified as tumor cells, dysplastic cells and false alarms. The latter consist of doublets and aggregates of more than two cells, binucleated cells, sperm aggregates and epithelial cells contaminated with bacteria. The different groups showed significant differences regarding the total rate of aggregates to single cells. In general, false alarms were very frequent in the positive region and impeded the statistical classification of the sample. The reduction of false alarms is a prerequisite for prescreening with flow instrumentation.

Cervix Uteri↗
PubMed1975

A laser Raman spectroscopic investigation of phospholipid and protein configurations in hemoglobin-free erythrocyte ghosts.

Configurations of both the protein and lipid components of human red blood cell ghosts are examined by laser Raman spectroscopy. Protein configuration is estimated from bands observed in the Amide III region at 1240-1267 cm-1 in water and the Amide I' region at 1630-1670 cm-1 observed in 2H2O. The protein fraction appears to contain 40-55 percent alpha-helix with little beta-configuration. The hydrophobic side chains of the phospholipid component, as interpreted from the 1060-1130 cm-1 C-C stretching region, are estimated to contain 55-65 percent all-trans rigid configuration. These estimated are within the limits set by other physical techniques.

Blood Proteins↗
PubMed1979

Laser flow cytometric light scatter and fluorescence pulse width and pulse rise-time sizing of mammalian cells.

In laser flow cytometry, an increasingly popular technique of analytical cytology, quantitative measurements of interest include cell and nuclear diameters. Electronic circuitry for a new cell sizing technique has been developed which measured the time that signal pulses from either fluorescence or light scatter sensors exceed a preset constant fraction of the peak signal amplitude (pulse width) or the time that it takes a signal to rise between constant fractions of the peak signal amplitude on the rising side of the pulse (pulse rise-time). These pulse width or pulse rise-time measurements were related to cell or nuclear diameters and were used in combination to determine nuclear size to cell size ratios. This method of sizing was found to be independent of fluorescent or light-absorbing stain intensity, linearly related to cell or nuclear diameter, and capable of resolving small diameter differences.

Animals↗