Assessment of Effects of Laser Light Combining Three Wavelengths (450, 520 and 640 nm) on Temperature Increase and Depth of Tissue Lesions in an Ex Vivo Study

Background: Lasers are widely used in medicine in soft and hard tissue surgeries and biostimulation. Studies found in literature typically compare the effects of single-wavelength lasers on tissues or cell cultures. In our study, we used a diode laser capable of emitting three components of visible light (640 nm, red; 520 nm, green; 450 nm, blue) and combining them in a single beam. The aim of the study was to assess the effects of laser radiation in the visible spectrum on tissue in vitro, depending on the wavelength and pulse width. Methods: All irradiations were performed using the same output power (1.5 W). We used various duty cycles: 10, 50, 80 and 100% with 100 Hz frequency. Maximum superficial temperature, rate of temperature increase and lesion depth were investigated. Results: Maximum superficial temperature was observed for 450 + 520 nm irradiation (100% duty cycle). The highest rate of increase of temperature was noted for 450 + 520 nm (100% duty cycle). Maximum lesion depth was observed in case of three-wavelength irradiation (450 + 520 + 640 nm) for 100, 80 and 50% duty cycles. Conclusions: The synergistic effect of two-wavelength (450 + 520 nm) irradiation was observed in case of maximum temperature measurement. The deepest depth of lesion was noted after three-wavelength irradiation (450 + 520 + 640 nm).

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In vitro characterisation of ultrasound-induced heating effects in the mother and fetus: A clinical perspective

Ultrasound ◽

10.1177/1742271x20953197 ◽

2020 ◽

pp. 1742271X2095319

Author(s):

Stephanie F Smith ◽

Piero Miloro ◽

Richard Axell ◽

Gail ter Haar ◽

Christoph Lees

Keyword(s):

Temperature Increase ◽

Skin Surface ◽

Maximum Temperature ◽

Factors Affecting ◽

Bone Interface ◽

Heating Effects ◽

Power Setting ◽

Lower Temperature

Introduction The quantification of heating effects during exposure to ultrasound is usually based on laboratory experiments in water and is assessed using extrapolated parameters such as the thermal index. In our study, we have measured the temperature increase directly in a simulator of the maternal–fetal environment, the ‘ISUOG Phantom’, using clinically relevant ultrasound scanners, transducers and exposure conditions. Methods The study was carried out using an instrumented phantom designed to represent the pregnant maternal abdomen and which enabled temperature recordings at positions in tissue mimics which represented the skin surface, sub-surface, amniotic fluid and fetal bone interface. We tested four different transducers on a commercial diagnostic scanner. The effects of scan duration, presence of a circulating fluid, pre-set and power were recorded. Results The highest temperature increase was always at the transducer–skin interface, where temperature increases between 1.4°C and 9.5°C were observed; lower temperature rises, between 0.1°C and 1.0°C, were observed deeper in tissue and at the bone interface. Doppler modes generated the highest temperature increases. Most of the heating occurred in the first 3 minutes of exposure, with the presence of a circulating fluid having a limited effect. The power setting affected the maximum temperature increase proportionally, with peak temperature increasing from 4.3°C to 6.7°C when power was increased from 63% to 100%. Conclusions Although this phantom provides a crude mimic of the in vivo conditions, the overall results showed good repeatability and agreement with previously published experiments. All studies showed that the temperature rises observed fell within the recommendations of international regulatory bodies. However, it is important that the operator should be aware of factors affecting the temperature increase.

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Antiplatelet drugs and generation of thrombin in clotting blood

Blood ◽

10.1182/blood.v80.8.2006.2006 ◽

1992 ◽

Vol 80 (8) ◽

pp. 2006-2011 ◽

Cited By ~ 84

Author(s):

A Szczeklik ◽

M Krzanowski ◽

P Gora ◽

J Radwan

Keyword(s):

Oral Administration ◽

Thrombin Generation ◽

Ex Vivo ◽

Coagulation Factors ◽

Antiplatelet Drugs ◽

Specific Marker ◽

Rate Of Increase ◽

Synthase Inhibitor ◽

Thrombin Formation

Abstract Platelets participate in formation of thrombin through secretion of coagulation factors and by providing a catalytic surface on which prothrombinase complex is assembled. We studied the effects of four antiplatelet drugs on thrombin formation in healthy volunteers. Thrombin generation was monitored both in vitro--in recalcified plasma-- and ex vivo--in blood emerging from a standardized skin microvasculature injury, which also served to determine bleeding time. A mathematical model has been developed to describe the latter reaction. It is based on estimation of the rate of increase in fibrinopeptide A (FPA), a specific marker of thrombin activity, in blood emerging from skin incisions. Two hours after the ingestion of 500 mg of aspirin, thrombin formation became significantly impaired both in vitro and ex vivo. In contrast, 2 hours after the oral administration of placebo, indomethacin 50 mg, or OKY-046 (a thromboxane synthase inhibitor) 400 mg, thrombinogenesis remained unaltered. Ticlopidine, studied either 3 hours after 500 mg oral administration, or after 5 days of intake at a daily dose of 500 mg, had no effect on thrombin generation. Thus, aspirin, contrary to other antiplatelet drugs, depresses thrombin formation in clotting blood, a phenomenon that might be of clinical relevance. It is suggested that aspirin exerts this effect by acetylating prothrombin and/or macromolecules of platelet membrane.

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671Assessment of irrigated-tip radiofrequency catheter ablation lesion characteristics using different irrigation fluids on ex-vivo bovine myocardium

EP Europace ◽

10.1093/europace/euaa162.304 ◽

2020 ◽

Vol 22 (Supplement_1) ◽

Author(s):

B Candemir ◽

E Baskovski ◽

K Esenboga ◽

H Yorgun ◽

K Aytemir ◽

...

Keyword(s):

Catheter Ablation ◽

Normal Saline ◽

Ex Vivo ◽

Clinical Success ◽

Ringer Lactate ◽

Lesion Depth ◽

Irrigation Solution ◽

Bovine Myocardium

Abstract Introduction Certain arrythmias, particularly of ventricular origin, necessitate deep lesions in order to achieve clinical success. The introduction of irrigated-tip radiofrequency (RF) catheters has allowed creation of deeper lesions and has decreased char formation. Although normal saline has been used as a standard solution, recent observations have suggested less ionic solutions may increase lesion depth. In this in-vitro study we aimed to characterize lesions created by irrigated-tip RF catheters using standard normal saline(NS), half-normal saline (HNS), and HNS-%2.5Dextrose (HNS-DEX/2) combination solutions. METHODS Bovine myocardium was placed firstly in ringer-lactate bath. Using irrigated-tip RF catheter ablation lesions were created serially using 30, 40, 50, 60, 70Watts with NS, HNS and HNS-DEX/2 as irrigation solutions. Lesion depths, steam pops and impedance drops were measured. Subsequently the experiment was repeated in normal saline bath. RESULTS Both HNS-DEX/2 and HNS irrigation solutions increase lesion depths when compared to normal saline (Table 1, Figure 1). Steam pops were more common and earlier with HNS-DEX/2 and HNS. DISCUSSION AND CONCLUSION Our findings suggest that less ionic irrigation solutions lead to increased lesion depths using similar RF power. If confirmed in-vivo, HNS and, particularly, HNS-DEX/2 as irrigation solution may increase ablation success for intramural/deep myocardial arrhythmic foci. Additionally, studies to assess safety of this strategy are necessary as intuitively deeper lesions may lead to more complications. Table 1 Irrigation Solution/Bath solution 30W/30ml(Lesion depth mm)(Impedance drop) 40W/30ml(Lesion depth mm)(Impedance drop) 50W/30ml(Lesion depth mm)(Impedance drop) 60W/30ml(Lesion depth mm)(Impedance drop) 70W/30ml(Lesion depth mm)(Impedance drop) HNS+%2.5D / Ringer Lactate 470->61 4.583->63 5.074->62SP+(32s) 6.080->66SP+(27s) 7.577->65SP+(26s) HNS/ Ringer Lactate 3.590->65 4.580->63SP+(34s) 5.073->59SP+(33s) 5.580->56SP+(28s) 6.583->64SP+(22s) NS/ Ringer Lactate 3.077->60 472->59 4.576->61 5.081->56 674->55 SP+(30s) HNS+%2.5D/Normal saline 3.573->67 598->63 5.573->58SP+(28s) 697->76SP+(26s) 7.570->58SP (25s) HNS/Normal saline 3.563->58 4.066->52 4.567->52 5.575->52 788->60SP+(28s) NS/Normal saline 2.566->58 3.063->52 4.073->58 5.077->55 5.568->44 Lesions created by irrigated tip radiofrequency catheter with bovine myocardium Abstract Figure 1

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Using 445 nm and 970 nm Lasers on Dental Implants—An In Vitro Study on Change in Temperature and Surface Alterations

Materials ◽

10.3390/ma12233934 ◽

2019 ◽

Vol 12 (23) ◽

pp. 3934

Author(s):

Sebastian Malmqvist ◽

Anders Liljeborg ◽

Talat Qadri ◽

Gunnar Johannsen ◽

Annsofi Johannsen

Keyword(s):

Laser Irradiation ◽

Dental Implants ◽

Temperature Increase ◽

Glass Ionomer Cement ◽

Cooling Water ◽

In Vitro Study ◽

Maximum Temperature ◽

Water Cooling ◽

Ionomer Cement

The aim of this study was to evaluate the safety of using a 445 nm laser on dental implants by comparing it with a laser with 970 nm wavelength. Two models, a pig mandible and glass ionomer cement, were used to evaluate the temperature increase in dental implants during laser irradiation with both wavelengths. Temperature was measured every second at four different places on the dental implants. Different power settings, effects of water cooling, distance of the laser fibre to the dental implant and continuous comparison to a pulsed laser beam were tested. Surface alterations on titanium discs after laser irradiation for 4 min at 2.0 W, were analysed in a scanning electron microscope (SEM). The maximum temperature and time to reach each of the thresholds were comparable between the 445 nm and 970 nm lasers. Neither the 445 nm nor the 970 nm wavelength showed any signs of surface alterations on the titanium discs. Using a 445 nm laser on dental implants is as safe as using a 970 nm laser, in terms of temperature increase and surface alterations. Applying a generous amount of cooling water and irradiating in short intervals is important when using lasers on dental implants.

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Antiplatelet drugs and generation of thrombin in clotting blood

Blood ◽

10.1182/blood.v80.8.2006.bloodjournal8082006 ◽

1992 ◽

Vol 80 (8) ◽

pp. 2006-2011 ◽

Cited By ~ 1

Author(s):

A Szczeklik ◽

M Krzanowski ◽

P Gora ◽

J Radwan

Keyword(s):

Oral Administration ◽

Thrombin Generation ◽

Ex Vivo ◽

Coagulation Factors ◽

Antiplatelet Drugs ◽

Specific Marker ◽

Rate Of Increase ◽

Synthase Inhibitor ◽

Thrombin Formation

Platelets participate in formation of thrombin through secretion of coagulation factors and by providing a catalytic surface on which prothrombinase complex is assembled. We studied the effects of four antiplatelet drugs on thrombin formation in healthy volunteers. Thrombin generation was monitored both in vitro--in recalcified plasma-- and ex vivo--in blood emerging from a standardized skin microvasculature injury, which also served to determine bleeding time. A mathematical model has been developed to describe the latter reaction. It is based on estimation of the rate of increase in fibrinopeptide A (FPA), a specific marker of thrombin activity, in blood emerging from skin incisions. Two hours after the ingestion of 500 mg of aspirin, thrombin formation became significantly impaired both in vitro and ex vivo. In contrast, 2 hours after the oral administration of placebo, indomethacin 50 mg, or OKY-046 (a thromboxane synthase inhibitor) 400 mg, thrombinogenesis remained unaltered. Ticlopidine, studied either 3 hours after 500 mg oral administration, or after 5 days of intake at a daily dose of 500 mg, had no effect on thrombin generation. Thus, aspirin, contrary to other antiplatelet drugs, depresses thrombin formation in clotting blood, a phenomenon that might be of clinical relevance. It is suggested that aspirin exerts this effect by acetylating prothrombin and/or macromolecules of platelet membrane.

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Acoustic-Reflex Dynamics for Pulsed Signals

Journal of Speech and Hearing Research ◽

10.1044/jshr.2102.295 ◽

1978 ◽

Vol 21 (2) ◽

pp. 295-308

Author(s):

Terry L. Wiley ◽

Raymond S. Karlovich

Keyword(s):

Duty Cycle ◽

Acoustic Impedance ◽

Normal Hearing ◽

Broadband Noise ◽

Threshold Shift ◽

Temporary Threshold Shift ◽

Acoustic Reflex ◽

Stapedius Muscle ◽

Duty Cycles

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

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Effects of the Tibetan herbal preparation PADMA 28 on blood lipids and lipid oxidisability in subjects with mild hypercholesterolaemia

VASA ◽

10.1024/0301-1526.34.1.11 ◽

2005 ◽

Vol 34 (1) ◽

pp. 11-17 ◽

Cited By ~ 12

Author(s):

Brunner-La Rocca ◽

Schindler ◽

Schlumpf ◽

Saller ◽

Suter

Keyword(s):

Endothelial Dysfunction ◽

Blood Lipids ◽

Ex Vivo ◽

Hdl Cholesterol ◽

Blood Lipid ◽

Tibetan Medicine ◽

Double Blind ◽

Intraarterial Infusion ◽

Padma 28

Background: Previous studies showed an anti-atherosclerotic effect of PADMA 28, an herbal formula based on Tibetan medicine. As the mechanisms of action are not fully understood, we investigated whether PADMA 28 may lower blood lipids and lipid oxidisability, and affect early endothelial dysfunction. Patients and methods: Sixty otherwise healthy subjects with total cholesterol ≥5.2 mmol/l and < 8.0 mmol/l were randomly assigned to placebo or PADMA 28, 3 x 2 capsules daily, for 4 weeks (double-blind). Blood lipids (total, LDL-, and HDL-cholesterol, triglycerides, Apo-lipoprotein A1 and B) and ex vivo lipid oxidisability were measured before and after treatment. In a subset of 24 subjects, endothelial function was assessed using venous occlusion plethysmography with intraarterial infusion of acetylcholine. Isolated LDL and plasma both untreated and pre-treated with PADMA 28 extract were oxidised by the radical generator AAPH. Conjugated diene formation was measured at 245 nm. Results: Blood lipids did not change during the study in both groups. In contrast to previous reports in mild hypercholesterolaemia, no endothelial dysfunction was seen and, consequently, was not influenced by therapy. Ex vivo blood lipid oxidisability was significantly reduced with PADMA 28 (area under curve: 5.29 ± 1.62 to 4.99 ± 1.46, p = 0.01), and remained unchanged in the placebo group (5.33 ± 1.88 to 5.18 ± 1.78, p > 0.1). This effect persisted one week after cessation of medication. In vitro experiments confirmed the prevention of lipid peroxidation in the presence of PADMA 28 extracts. Persistent protection was also seen for LDL isolated from PADMA 28-pretreated blood after being subjected to rigorous purification. Conclusions: This study suggests that the inhibition of blood lipid oxidisability by PADMA 28 may play a role in its anti-atherosclerotic effect.

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The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000116 ◽

2012 ◽

Vol 82 (3) ◽

pp. 228-232 ◽

Cited By ~ 7

Author(s):

Mauro Serafini ◽

Giuseppa Morabito

Keyword(s):

Antioxidant Capacity ◽

Dietary Intervention ◽

Ex Vivo ◽

The Body ◽

Dietary Polyphenols ◽

Enzymatic Antioxidant ◽

Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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