Lower energy and pulse stacking. A safer alternative for skin tightening using fractional CO2 laser.

PURPOSE: To evaluate the effect of different energies and stacking in skin shrinkage. METHODS: Three decreasing settings of a fractional CO2 laser were applied to the abdomen of Twenty five Wistar rats divided into three groups. Group I (n=5) was histologically evaluated for microthermal zones dimensions. Groups II and III (n=10 each) were macroscopic evaluated with freeware ImageJ for area contraction immediately and after 30 and 60 days. RESULTS: No statistical significance was found within microthermal zone histological dimensions (Group I) in all settings studied. (Ablation depth: 76.90 to 97.18µm; Coagulation depth: 186.01 to 219.84 µm). In Group II, macroscopic evaluation showed that all settings cause significant immediate skin contraction. The highest setting cause significant more intense tightening effect initially, contracting skin area from 258.65 to 179.09 mm2. The same pattern was observed in Group III. At 30 and 60 days, the lowest setting significantly sustained contraction. CONCLUSION: Lower fractional CO2 laser energies associated to pulse stacking could cause consistent and long lasting tissue contraction in rats.

Lower energy and pulse stacking. A safer alternative for skin tightening using fractional CO2 laser

PURPOSE : To evaluate the effect of different energies and stacking in skin shrinkage. METHODS : Three decreasing settings of a fractional CO2 laser were applied to the abdomen of Twenty five Wistar rats divided into three groups. Group I (n=5) was histologically evaluated for microthermal zones dimensions. Groups II and III (n=10 each) were macroscopic evaluated with freeware ImageJ for area contraction immediately and after 30 and 60 days. RESULTS : No statistical significance was found within microthermal zone histological dimensions (Group I) in all settings studied. (Ablation depth: 76.90 to 97.18µm; Coagulation depth: 186.01 to 219.84 µm). In Group II, macroscopic evaluation showed that all settings cause significant immediate skin contraction. The highest setting cause significant more intense tightening effect initially, contracting skin area from 258.65 to 179.09 mm2. The same pattern was observed in Group III. At 30 and 60 days, the lowest setting significantly sustained contraction. CONCLUSION : Lower fractional CO2 laser energies associated to pulse stacking could cause consistent and long lasting tissue contraction in rats.

[Normal tissue tolerance to external beam radiation therapy: anal canal]. / Dose de tolérance à l'irradiation des tissus sains: le canal anal.

The anal canal is regarded as an organ at risk more often in pelvis radiation, but also in brachytherapy. Acute or chronic complications depend on its different components and are different from the anal margin or the rectum. The toxicity scale can be the NCI CT C version 3, completed by the tardive toxicity SOMALENT scale. The mean dose and maximal dose are recognized as predictors of complications. The maximum recommended dose despite the paucity of literature is 55 Gy.

[Tonus state of arterial vessels in the brain hemispheres depending on sex and age of patients with arterial hypertension, which have suffered from Chernobyl accident].

The author established distinctive sex and age differences in tonus state of arterial little and medium size vessels located in the brain hemispheres in patients with arterial hypertension, which have suffered from Chernobyl accident, using tetrapolar impedance plethysmography (RA5-01).

[Low-energy wideband electromagnetic radiation and manual therapy in the treatment of neurological manifestations of spinal osteochondrosis].

It is shown that the advanced technique of low-energy wideband electromagnetic radiation improves vascular tonicity and peripheral circulation while a modified technique of manual therapy facilitates movements in the affected part of the spine and reduces tonicity of the muscles involved in the pathological process.

[Effects of electromagnetic fields on tonicity of cerebral vessels and arterial pressure].

Investigations performed by the authors show that normalization of the mechanisms of vegetative regulation of arterial pressure and cerebral vessels tonicity in young patients with sympathico-tonic vegetative dystonia can be achieved by combined use of constant magnetic field (magnetic induction 60 mTl, penetration 10 mm, area 1.5 cm2) and monochromatic electromagnetic wave (length 0.47 mcm, frequency 6 x 10(14) Hz, penetration 1.5 mm and light spot 7 mm) which are directed to a biologically active point C7 shen-men from both sides simultaneously for 3 min, at 11 a.m. to 13 p.m. once a day, for 10 days.

Active medullary control of atonia in week-old rats.

Muscle atonia is a central feature of adult REM sleep which has recently been demonstrated to be a component of sleep in rats as young as 2 days of age (P2). The neural generation of atonia, which depends on mesopontine and medullary structures, is not fully understood in adults and has never been described in infants. In the present experiments we used electrical stimulation in decerebrated pups to identify an inhibitory area within the medial medulla of P7-10 rats. Muscle tone inhibition was consistently found on or near the midline within the ventromedial medulla, dorsal to the inferior olive, in an area that includes the nucleus gigantocellularis, nucleus paramedianus, and raphe obscurus. Chemical infusions in the same region revealed inhibitory responses to quisqualic acid but not to carbachol or corticotropin-releasing factor. Next, extracellular recordings within the medullary inhibitory area revealed neurons with atonia-on profiles; tone-on neurons were also found, typically at more lateral sites. Finally, in non-decerebrated pups, chemical lesions within the inhibitory area resulted in significant reductions in atonia durations, as well as decoupling of atonia from a second component of infant sleep, myoclonic twitching; specifically, twitches occasionally occurred during periods of high muscle tone, a condition reminiscent of "REM without atonia" as described in adults. In summary, we document the existence of an area within the ventromedial medulla of infant rats that (i) causes atonia when stimulated; (ii) contains units that exhibit atonia-related discharge profiles during sleep-wake cycling; and (iii) when lesioned, results in the partial loss of atonia and decoupling of the components of sleep. All together, these findings demonstrate that muscle atonia is actively regulated very early in ontogeny.

Static magnetic fields alter arteriolar tone in vivo.

This study was designed to directly quantify the effect of localized static magnetic field (SMF) exposure on the diameter of microvessels in adult rat skeletal muscle in vivo. Microvascular networks in the exteriorized rat spinotrapezius microvasculature were exposed to a localized, uniform 70 mT SMF for 15 min. Arteriolar vessel diameters were measured; and the extent of vessel contraction, microvascular tone, was calculated before exposure, immediately after exposure, and 15 and 30 min after removal of the field. A calculated value of high tone corresponds to vessels that are vasoconstricted and a calculated value of low tone refers to vessels that are vasodilated. Vessels with initial tone <15% showed an increasing trend in tone and, conversely, vessels with initial tone >15% showed a significant (P < 0.05) decrease in tone 15 and 30 min following application, respectively. Further classification of the data with regards to the initial vessel diameter demonstrated that vessels with initial diameters <30 microm and initial tone <15%, smaller diameter vessels that are initially vasodilated, showed significant (P < 0.05) increase in tone immediately, 15 and 30 min following SMF exposure. Additionally, <30 microm vessels with >15% initial tone, smaller diameter vessels that are initially vasoconstricted, demonstrated a significant (P < 0.05) decrease in tone 30 min after SMF exposure. Vessels with initial diameters >30 microm had no significant response to the SMF. These results imply that SMF exposure influences arteriolar diameters, and therefore microvascular tone, in a restorative fashion acting to normalize the tone to the median tone value of 15% following exposure. Because this response occurs primarily in the resistance arterioles, which significantly influence tissue perfusion, SMF application could be efficacious for the treatment of both ischemic and edematous tissue disorders involving compromised microvascular function.

Changes in the excitability of hindlimb motoneurons during muscular atonia induced by stimulating the pedunculopontine tegmental nucleus in cats.

We have previously reported that electrical stimulation delivered to the ventral part of the pedunculopontine tegmental nucleus (PPN) produced postural atonia in acutely decerebrated cats [Neuroscience 119 (2003) 293]. The present study was designed to elucidate synaptic mechanisms acting on motoneurons during postural atonia induced by PPN stimulation. Intracellular recording was performed from 72 hindlimb motoneurons innervating extensor and flexor muscles, and the changes in excitability of the motoneurons following the PPN stimulation were examined. Repetitive electrical stimulation (20-50 microA, 50 Hz, 5-10 s) of the PPN hyperpolarized the membrane potentials of both the extensor and flexor motoneurons by 2.0-12 mV (6.0 +/- 2.3 mV, n = 72). The membrane hyperpolarization persisted for 10-20 s even after termination of the stimulation. During the PPN stimulation, the membrane hyperpolarization was associated with decreases in the firing capability (n = 28) and input resistance (28.5 +/- 6.7%, n = 14) of the motoneurons. Moreover the amplitude of Ia excitatory postsynaptic potentials was also reduced (44.1 +/- 13.4%, n = 14). After the PPN stimulation, these parameters immediately returned despite that the membrane hyperpolarization persisted. Iontophoretic injections of chloride ions into the motoneurons reversed the polarity of the membrane hyperpolarization during the PPN stimulation. The polarity of the outlasting hyperpolarization however was not reversed. These findings suggest that a postsynaptic inhibitory mechanism, which was mediated by chloride ions, was acting on hindlimb motoneurons during PPN-induced postural atonia. However the outlasting motoneuron hyperpolarization was not due to the postsynaptic inhibition but it could be due to a decrease in the activity of descending excitatory systems. The functional role of the PPN in the regulation of postural muscle tone is discussed with respect to the control of behavioral states of animals.

[Comparative characteristic of blood filling and vascular tone in arterial vessels of patients with arterial hypertension and somatic form of autonomic dysfunction after Chernobyl accident (according to rheoencephalography and rheovasography data)]. / Sravnitel'naia kharakteristika krovenapolneniia i tonusa arterial'nykh sosudov u bol'nykh s somatoformnoi vegetativnoi disfunktsiei i arterial'noi gipertenziei, postradavshikh vsledstvie avarii na ChAES (po dannym reoéntsefalo- i reovazografii).

Clear-cut distinction in blood vascular filling and vascular tone of arterial vessels of the cerebral hemisphere and shanks in patients suffered from Chernobyl accident and with arterial hypertension and vegetative dysfunction manifested somatically has been detected by means of impedance tetrapolar plethysmography (rheoanalyzer RA5-01).

Effect of in vivo heart irradiation on coronary reactivity in the rat.

The frequent exposure of the heart to radiation during thoracic tumor radiotherapy often results in chronic impairment of myocardial function. The aim of the present investigation was to evaluate the effect of irradiation on coronary vascular tone in rat hearts exposed in vivo to a single dose of 20 Gy gamma rays. The ability of rat hearts to respond to changes in coronary reactivity was analyzed 1, 15, 30 and 60 days following cardiac irradiation, using the Langendorff model, after perfusion of either L-nitro-arginine (LNA), an inhibitor of nitric oxide synthetase or SIN 1, a nitric oxide donor drug. LNA-induced vasoconstriction and SIN 1-induced vasodilation were lost respectively 15 days and 30 days after irradiation, and associated with smooth muscle cell alterations observed in microscopy, but without any changes in myocardial MDA levels. Thus, our results suggest that 1) endothelium may represent an early and specific radiation target, characterized by radiation-induced vascular tone dysfunctions, with no detectable microscopical changes; 2) alterations are progressive, resulting first from endothelial damage, followed by smooth muscle cell injuries. In conclusion, a local cardiac irradiation induced cellular dysfunction, characterized by a loss of coronary reactivity without changes of the lipid peroxidation index in the hearts.

A combined mechanical and X-ray diffraction study of stretch potentiation in single frog muscle fibres.

The nature of the force (T) response during and after steady lengthening has been investigated in tetanized single muscle fibres from Rana temporaria (4 C; 2.15 micrometer sarcomere length) by determining both the intensity of the third order myosin meridional X-ray reflection (IM3) and the stiffness (e) of a selected population of sarcomeres within the fibre. With respect to the value at the isometric tetanus plateau (To), IM3 was depressed to 0.67 +/- 0.04 during steady lengthening at approximately 160 nm s(-1) (T approximately 1.7) and recovered to 0.86 +/- 0.05 during the 250 ms period of after-stretch potentiation following the rapid decay of force at the end of lengthening (T approximately 1.3); under the same conditions stiffness increased to 1.25 +/- 0.02 and to 1.12 +/- 0.03, respectively. After subtraction of the contribution of myofilaments to the half-sarcomere compliance, stiffness measurements indicated that (1) during lengthening the cross-bridge number rises to 1.8 times the original isometric value and the average degree of cross-bridge strain is similar to that induced by the force-generating process in isometric conditions (2.3 nm), and (2) after-stretch potentiation is explained by a residual larger cross-bridge number. Structural data are compatible with mechanical data if the axial dispersion of attached heads is doubled during steady lengthening and recovers half-way towards the original isometric value during after-stretch potentiation.

Early effects of acute gamma-radiation on vascular arterial tone.

1. To determine the acute effects of irradiation on the functionality of vessel, rat aortic rings were mounted in an organ bath for isometric tension measurements and irradiated (60Co, 1 Gy min(-1), 15 min). 2. Irradiation, which is without effect on non-contracted or endothelium-denuded vessels, led to an immediate and reversible increase in vascular tone on (-)-phenylephrine (1 microM)-precontracted aortic rings. The tension reached a plateau about 5 min after the beginning of irradiation. 3. The maximal radiation-induced contraction occurred on aortic rings relaxed by acetylcholine (ACh) (1 microM). In this condition, the addition of catalase (1000 u ml(-1)), which reduces hydrogen peroxide, and DMSO (0.1% v/v), which scavenges hydroxyl radical, had no influence on tension level while superoxide dismutase (SOD) (100 u ml(-1)), a superoxide anion scavenger, reduced the observed contraction. A similar result was obtained in the presence of indomethacin (10 microM), a cyclo-oxygenase blocker. 4. Pretreatment of rings with the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME) (10-100 microM) inhibited the radiation-induced contraction. 5. This effect was dose rate-dependent and even occurred for a very low dose rate (0.06 Gy min(-1)). 6. The present results indicate that gamma-radiation induces an instantaneous vascular tone increase that is endothelium and dose rate-dependent. This effect is (i) maximal when nitric oxide (NO) is produced, (ii) greatly reduced by SOD and (iii) inhibited by L-NAME, suggesting a major involvement of complexes between NO and superoxide anion.

Nitric oxide, a possible mediator of 1,4-dihydropyridine-induced photorelaxation of vascular smooth muscle.

1. In rat aortic tissues pre-contracted with phenylephrine, certain 1,4-dihydropyridines (DHPs) such as Bay K 8644 (0.1 microM), PN 202791 (1 microM), RK 30 (1 microM), NI 104 (1 microM) and NI 105 (1 microM) enhanced photoactivated relaxations (photorelaxation or PR) whereas NI 72, NI 85, NI 99, NI 102, amlodipine, felodipine, nifedipine and nimodipine were inactive. 2. The PR inducing effects of Bay K 8644 were mimicked by the diabetogenic agent, streptozotocin (STZ). 3. Solutions of Bay K 8644 which had been irradiated for various periods of time initiated light independent transient relaxations followed by contractile responses in aortic tissue partially contracted with phenylephrine. With exposure times to light of 30 to 120 min, the intensity of the relaxation response to irradiated Bay K 8644 increased from 26 +/- 3.3 to 71 +/- 3.7% of the maximum contractile response to phenylephrine (n = 5). Conversely the contractile responses decreased, from 84.2 +/- 4.1 to 19.8 +/- 10.4% of the maximum contractile response to phenylephrine (n = 5). 4. Superoxide ions, generated by incubation of xanthine (2mM) plus xanthine oxidase (10 mu ml-1) in physiological saline solution (PSS) NaCl 118, KCl 4.7, CaCl2 2.5, KH2PO4 1.2, MgSO4 1.2, NaHCO3 12.5 and glucose 11.1 (mM) for 1 h. reduced the PR induced by DHPs, STZ, and also NO-induced relaxations of rat aortic preparations. 5. Direct measurements of NO indicate that, following exposure to a polychromatic light source, equimolar concentrations (0.1 mM) of the DHP compounds that enhance PR, as well as STZ, photodegrade to release NO (25 +/- 2-40.3 +/- 5.9 nmol min-1, n = 6). 6. Structure-activity studies indicate that a nitro group at the -3 position of the dihydropyridine ring is essential for DHPs to support PR. 7. These data suggest that the photodegradation of DHPs and STZ leading to the release of NO provides the primary cellular process underlying the PR response.

Immediate mechanical reactions of isolated human detrusor muscle on x-irradiation.

The mechanical activity (isotonic registration) of isolated detrusor (smooth) muscle preparations from the human urinary bladder (surgical material) is investigated. The preparations reacted on X-irradiation (50 kV) with an immediate dose-dependent tonic contraction at threshold-doses of 100 to 1000 R (1 to 3 kR/min). The contraction was either reversible, semireversible or persistent, and the basal muscle tone was elevated. A tachyphylactic reaction was observed. The phasic activity of the preparations was temporarily increased, then inhibited after irradiation. The radiation-induced changes of the human and guinea-pig detrusor muscle are compared and their possible relation to the functional disturbances of the urinary bladder after radiotherapy is discussed.

Swelling of the upper extremity, function and muscle strength of shoulder joint following mastectomy combined with radiotherapy.

Swelling of the arm, mobility of the shoulder joint and muscle strength were examined in 76 patients with breast cancer 4.5 to 14 years (mean 8 years) after primary therapy. Marked arm swelling was found on the operated side in 31% of the patients operated by radical mastectomy and in 18% of those having undergone total mastectomy. The swelling was more marked in the upper arm than in the forearm. Patients irradiated postoperatively with a megavoltage technique showed more often and more oedema than those treated with a kilovoltage technique. Obese patients had more swelling than patients of normal weight. Of the various movements of the shoulder joint, abduction, adduction, flexion, extension, horizontal extension and internal rotation were significantly reduced on the operated side in comparison with the non-operated side, but the differences were not great. Neither swelling of the arm nor the patient's weight had any effect on the function of the shoulder joint, as expressed in terms of abduction. Of the muscle groups in the shoulder joint adductors, flexors and extensors were significantly weaker on the operated than on the non-operated side. The muscle strength of the operated side averaged 25% weaker than that of the control side. Swelling of the arm did not reduce the muscle strength of the shoulder joint.

Action of tetrodotoxin on the contractile responses of isolated guinea-pig urinary bladder preparation to x-irradiation and to electrical stimulation.

Tetrodotoxin (10- minus 8 to 10- minus 6 g/ml) blocked the contractile responses of isolated guinea-pig urinary bladder preparation to electrical (25 and 100 Hz) neural but not to transmural stimulation and to X-irradiation (50 kV, 20 kR/min, 20 kR). The irradiation had no influence on the bladder responses to electrical and hormonal (acetylcholine and histamine) stimulation. It is concluded that the X-ray-induced contraction is of myogenic origin and that it is possibly not related to the electro-mechanical coupling system.