Efficacy of different carrier gases for barrier discharge plasma generation compared to chlorhexidine on the survival of Pseudomonas aeruginosa embedded in biofilm in vitro.

Because of its antimicrobial properties, nonthermal plasma could serve as an alternative to chemical antisepsis in wound treatment. Therefore, this study investigated the inactivation of biofilm-embedded Pseudomonas aeruginosa SG81 by a surface barrier-discharged (SBD) plasma for 30, 60, 150 and 300 s. In order to optimize the efficacy of the plasma, different carrier gases (argon, argon admixed with 1% oxygen, and argon with increased humidity up to approx. 80%) were tested and compared against 0.1% chlorhexidine digluconate (CHG) exposure for 600 s. The antimicrobial efficacy was determined by calculating the difference between the numbers of colony-forming units (CFU) of treated and untreated biofilms. Living bacteria were distinguished from dead by fluorescent staining and confocal laser scanning microscopy. Both SBD plasmas and CHG showed significant antimicrobial effects compared to the untreated control. However, plasma treatment led to a higher antimicrobial reduction (argon plasma 4.9 log10 CFU/cm(2), argon with admixed oxygen 3 log10 CFU/cm(2), and with increased gas humidity 2.7 log10 CFU/cm(2) after 300 s) compared to CHG. In conclusion, SBD plasma is suitable as an alternative to CHG for inactivation of Pseudomonas aeruginosa embedded in biofilm. Further development of SBD plasma sources and research on the role of carrier gases and humidity may allow their clinical application for wound management in the future.

Efficacy of chlorhexidine, polihexanide and tissue-tolerable plasma against Pseudomonas aeruginosa biofilms grown on polystyrene and silicone materials.

BACKGROUND: The formation of biofilms is crucial in the pathogenesis of many acute and subacute microbial infections, including chronic wounds and foreign-body-related infections. Topical antimicrobial therapy with chemical antiseptics or physical treatment with tissue-tolerable plasma (TTP) may be promising to control bacterial infection. METHODS: We assessed the efficacy of 0.1% chlorhexidine digluconate (CHX), 0.02 and 0.04% polihexanide (polyhexamethylene biguanide, PHMB) and of TTP against Pseudomonas aeruginosa SG81 biofilm grown in microtitre plates (polystyrene) and on silicone materials in an artificial wound fluid. RESULTS: Overall, PHMB was as effective as CHX in reducing the total amount of biofilm (gentian violet assay) and in reducing the bacterial metabolism in biofilms (XTT assay). TTP also led to a significant reduction in colony-forming units. CONCLUSION: The antimicrobial activity of PHMB in biofilms is comparable to that of CHX. TTP could become an interesting physical alternative to chemical antisepsis in the future.

Antiseptic efficacy and tolerance of tissue-tolerable plasma compared with two wound antiseptics on artificially bacterially contaminated eyes from commercially slaughtered pigs.

AIM: To compare the tissue tolerance and efficacy of two wound antiseptics with tissue-tolerable plasma (TTP) on enucleated contaminated eyes from slaughtered pigs in order to draw consequences for the use of TTP on wounds. METHOD: The corneas of extracted eyes were contaminated with Staphylococcus aureus or Pseudomonas aeruginosa. One and 10 min after application of 10% povidone (PVP)-iodine and 0.04% polyhexanide, respectively, the eyes were rinsed with inactivating solution. To test TTP, the plasma pen meandered over the eyes at a speed of 30 mm/s and a distance of 5 mm; the eyes were then rinsed with balanced salt solution. The reduction factor was calculated by the difference between the logarithm of colony-forming units in the rinse before and after antisepsis or TTP application. RESULTS: The efficacy of TTP (reduction factor 2.4-2.9) was significantly higher (p < 0.001) than that of PVP-iodine and polyhexanide (reduction factor 1.7-2.1). CONCLUSION: TTP is more effective than the tested wound antiseptics. The lack of histological damage to the eyes of slaughtered pigs would seem to make its use as a wound antiseptic a viable alternative. In contrast to antiseptics, it supplies additional energy in the form of heat, electric fields and radicals by TTP.

Measurement of the individual exposure to 50 and 16 2/3 Hz magnetic fields within the Bavarian population.

This study investigates the individual magnetic field exposures at 16 2/3 and 50 Hz of 1952 people, selected from the Bavarian population. Personal flux density meters ("Field Watcher FW2A") were worn by the participants for 24 h. Every second, the flux density was recorded for both frequencies and for the three spatial axes (dynamic range per axis: several nT up to 100 microT at 50 Hz, 150 microT at 16 2/3 Hz). For 50 Hz fields, the mean of the 1,952 individual means was 0.101 microT and that of the individual medians was 0.047 microT. High level exposures occurred mainly during working hours. Only 2.4% of the subjects showed individual medians higher than 0.2 microT. About 53% of all volunteers were working on the day of recording. Levels for craftsmen (n = 148; mean individual mean: 0.166 microT) were generally higher than those for office workers (n = 624; mean individual mean: 0.107 microT). Flux densities exceeding 100 microT at 50 Hz were measured in 31 persons. The total time with such extreme exposures amounts to nearly 21 min, less than 0.001% of the total time for all measurements (5.3 years). To our knowledge, this is the first exposure study where 16 2/3 Hz magnetic fields (caused by electrified railways) have additionally been monitored over 24 h. For persons living next to railway lines, the mean individual mean (0.156 microT) and mean individual median (0.102 microT) were calculated. Over all, the mean exposures are only 0.1% of the magnetic flux density limit for 50 Hz (100 microT) and about 0.05% of the limit (300 microT) for 16 2/3 Hz recommended by the International Commission on Non-Ionizing Radiation Protection.

Mechanisms of circulatory and intestinal barrier dysfunction during whole body hyperthermia.

This work tested the hypotheses that splanchnic oxidant generation is important in determining heat tolerance and that inappropriate.NO production may be involved in circulatory dysfunction with heat stroke. We monitored colonic temperature (T(c)), heart rate, mean arterial pressure, and splanchnic blood flow (SBF) in anesthetized rats exposed to 40 degrees C ambient temperature. Heating rate, heating time, and thermal load determined heat tolerance. Portal blood was regularly collected for determination of radical and endotoxin content. Elevating T(c) from 37 to 41.5 degrees C reduced SBF by 40% and stimulated production of the radicals ceruloplasmin, semiquinone, and penta-coordinate iron(II) nitrosyl-heme (heme-.NO). Portal endotoxin concentration rose from 28 to 59 pg/ml (P < 0.05). Compared with heat stress alone, heat plus treatment with the nitric oxide synthase (NOS) antagonist N(omega)-nitro-L-arginine methyl ester (L-NAME) dose dependently depressed heme-.NO production and increased ceruloplasmin and semiquinone levels. L-NAME also significantly reduced lowered SBF, increased portal endotoxin concentration, and reduced heat tolerance (P < 0.05). The NOS II and diamine oxidase antagonist aminoguanidine, the superoxide anion scavenger superoxide dismutase, and the xanthine oxidase antagonist allopurinol slowed the rates of heme-.NO production, decreased ceruloplasmin and semiquinone levels, and preserved SBF. However, only aminoguanidine and allopurinol improved heat tolerance, and only allpourinol eliminated the rise in portal endotoxin content. We conclude that hyperthermia stimulates xanthine oxidase production of reactive oxygen species that activate metals and limit heat tolerance by promoting circulatory and intestinal barrier dysfunction. In addition, intact NOS activity is required for normal stress tolerance, whereas overproduction of.NO may contribute to the nonprogrammed splanchnic dilation that precedes vascular collapse with heat stroke.

[understanding and radiation hygiene assessment of solar UV exposure in Germany]. / Erfassung und strahlenhygienische Bewertung der solaren UV-Exposition in Deutschland.

In order to monitor the natural ultraviolet (UV) radiation and to assess it from the point of view of radiation hygiene, the Federal Office for Radiation Protection (BfS) and the Federal Environmental Agency (UBA) have built up a common network for UV monitoring. Since 1993, the ground-level solar UV radiation has been measured at four sites in Germany every 6 minutes, with spectroradiometers in the wavelength range between 290 and 400 nm. Because erythema (sunborn) is of special interest in terms of radiation hygiene, the erythemal weighted irradiance was used as a measure for the biological effect of UV exposure. For this purpose, the measured spectral irradiance was multiplied by the relative erythemal weighting function, and the resulting function integrated from 290 to 400 nm. In the summer months of June and July 1999, the erythemal irradiance exceeded regularly the value of 175 mW/m2 in the south of Germany. In the north, values of not less than 160 mW/m2 were measured during this period. These values correspond to an UV index of more than 7 or 6, respectively--a high exposure regarding to the classification of the German Radiation Protection Commission (SSK), for which (absolute) sun protection is recommend. Between 1995 and 1999, the four sites were characterized by a small increase of the ground-level UV exposure of approx. 10%. Nevertheless, in consideration of the manifold factors affecting the acquired data, the measuring period of 5 years is still insufficient to demonstrate an ozone-dependent effect.

Heat acclimation does not alter rat mesenteric artery response to norepinephrine.

Previous studies have shown that heat acclimation raises the temperature threshold for heat-induced splanchnic vasoconstriction in the rat (W. Haddad and M. Horowitz. Thermal Balance in Health and Disease, Advances in Pharmacological Sciences. Basel: Birkhauser, 1994, p. 203-208; M. Shochina, W. Haddad, U. Meiri, and M. Horo-witz. J. Therm. Biol. 21: 289-295, 1996). We tested the hypothesis that heat acclimation alters splanchnic resistance artery sensitivity to norepinephrine (NE). Male Sprague-Dawley rats (n = 5) were acclimated to 35 degreesC ambient temperature for 5-8 wk. Control rats (n = 5) were maintained at 22-23 degreesC ambient temperature for 5-7 wk. Small mesenteric artery segments (2- to 3-mm length, 100- to 340-micrometer ID) were isolated, cannulated at both ends, and pressurized to 50 mmHg. Artery luminal diameter was measured in response to cumulative doses of NE (10(-9) to 10(-5) M) by using video microscopy. NE dose response was measured at 37 and 43 degreesC bath temperatures. There were no differences in constriction responses to NE between acclimated and control rat arteries at either 37 or 43 degreesC. We conclude that acclimation does not alter rat mesenteric artery sensitivity to NE.

Hyperthermia stimulates nitric oxide formation: electron paramagnetic resonance detection of .NO-heme in blood.

Previous experiments from our laboratory have demonstrated that severe hyperthermia results in a selective loss of splanchnic vasoconstriction. Using electron paramagnetic resonance spectroscopy to scan whole blood samples collected in vivo from the portal vein and femoral artery of conscious unrestrained rats, we observed an increase in the concentration of spectroscopy-detectable species in portal venous blood of all heat-stressed animals. These spectra consisted of at least three distinct species: one with a broad feature having an effective g factor for the unpaired electron (g) of 2.06 assigned to the copper-binding acute phase protein ceruloplasmin, and two with narrower features that evolved at core temperatures > 39 degrees C representing a semiquinone radical and .NO-heme. This heat-induced signal displays the classic nitrogen triplet hyperfine structure (nitrogen hyperfine splitting constant = 17.5 gauss, centered at g = 2.012) that is consistent with a five-coordinate heme complex and is characteristic of an unpaired electron coupled to nitrogen in the ferrous .NO-heme adduct [(alpha 2+NO) beta 3+]2. The intensity of this signal increased approximately twofold as core temperature rose to > 39 degrees C, peaking 1 h post-heat exposure at greater than threefold basal concentration. This species was not seen in corresponding arterial blood samples. This is the first demonstration that whole body hyperthermia produces increased concentrations of radicals and metal binding proteins in the venous blood of the rat and suggests that severe hyperthermia stimulates an enhanced local release of .NO within the splanchnic circulation.

Heat stress does not sensitize rats to the toxic effects of bacterial lipopolysaccharide.

To determine whether heat stress sensitizes rats to lipopolysaccharide (LPS), four groups were examined: saline, LPS, heat stressed+saline, and heat stressed+LPS treated rats. Saline or LPS (Escherichia coli, 5 mg.kg-1 body weight, i.v.) was given after exposure to heat and at the same time of day for nonheated rats. Survival was monitored for 24 or 48 h; samples of liver and small intestine were obtained at 24 h for histological analysis. Thermal responses were similar (P > 0.05) for the heat stressed saline and LPS treated rats: mean values for maximum colon temperature were 43.0 +/- 0.1 and 42.9 +/- 0.1 degrees C, respectively. Mortality was similar for rats exposed to heat stress+saline (11%, 2/19) and heat stress+LPS (32%, 6/19). No lethality was observed in nonheated rats given saline or LPS. Tissue damage was similar in heat stress+saline and heat stress+LPS treated rats. Liver showed mild to severe degrees of coagulative necrosis while duodenum exhibited damage to the villous tips. These findings show that severe heat stress does not markedly sensitize the rat to the lethal activity of LPS.

[Combined cryocoagulation of ciliary body and retina in neovascular glaucoma. Initial experience]. / Kombinierte Kryokoagulation von Ziliarkörper und Retina bei Neovaskularisationsglaukom. Erste Erfahrungen.

UNLABELLED: Therapeutic success in neovascular glaucoma with conservative and surgical methods is sadly inadequate. Based on the encouraging results we have obtained with transconjunctival cyclocryothermy in primary glaucoma and with peripheral cryopexy (transconjunctival cryotherapy), we applied these two methods in combination to treat neovascular glaucoma. PATIENTS: A total of 25 eyes in 23 patients were treated with the above method. The average preoperative bulbar pressure was 43 mmHg. RESULTS: The highest average reduction of pressure was obtained in weeks 2-4 after treatment (20 mmHg); 40% of the eyes were still compensated after 4 months (below 22 mmHg), 35% showed bulbar pressures between 26-28 mmHg, and 25% showed bulbar pressures about 35 mmHg. These patients had no troublesome symptoms. In all cases, a good improvement of rubeosis iridis was observed. The combined cryotherapeutic method of treating neovascular glaucoma is efficient in controlling the internal bulbar pressure.

[Cryotherapy in the treatment of vitreous hemorrhage of various origin]. / Kryoterapeutické moznosti pri lécení sklivcového krvácení ruzné geneze.

In 54 eyes from the same number of patients transconjunctival cryotherapy was performed (12 points and 8-10 circular ones in the outer retinal periphery) to influence the absorption of vitreous haemorrhages of different aetiology. The most frequent cause was the proliferative stage of diabetic retinopathy (53.7%) and vascular changes in atherosclerosis (39%). Haemorrhage of the vitreous persisted on average for five months. Eight months after the intervention complete or partial reabsorption led to improvement of the eyesight in 74% of the patients, no change was recorded in 16.6% and further deterioration occurred in 9.4%. No serious per- or postoperative complications were recorded, the method is unpretentious, can be used in ambulatory patients, it is repeatable and suitable also as preparation before vitreous surgery.

[Equipment for spray-freezing in ophthalmology]. / Prístrojová technika pro spray freezing v oftalmologii.

The authors discuss the theoretical background of the method of spray/freezing for destructive processes and their advantages. They demonstrate a cryo-apparatus IKG 3 for liquid nitrogen which is part of the Dresden equipment and was elaborated by the department for cryomedicine of the "Carl Gustav Carus" Academy in cooperation with the Technical University in Dresden. The apparatus produces a fine dispensable spray of the cooling mixture and permits treatment even of small tissue areas.

[Clinical use of the spray-freezing method in ophthalmology]. / Klinické vyuzití metody spray freezing v oftalmologii.

The authors describe a therapeutic method using spray freezing in the treatment of malignant tumours of the eyelids and conjunctivae, trichiasis and distichiasis and forms of conjunctivitis vernalis which cannot be checked by drugs. The authors discuss the results assembled in a large group of patients during 1971-1987 (4,084 patients). The results provide convincing evidence that the method is successful in these indications and that it has preference before contact freezing. Treatment of all patients was implemented using the Dresden cryotherapeutic apparatus IKG 3.

Splanchnic sympathetic nerve activity and circulating catecholamines in the hyperthermic rat.

The mechanisms responsible for the initial rise in splanchnic vascular resistance with environmental heating are controversial, and those responsible for the subsequent fall in splanchnic resistance in the severely hyperthermic animal are unknown. Thus we examined the effect of environmental heating on plasma catecholamine concentration, splanchnic sympathetic nerve activity (SNA), and select blood chemistries. In one study, 25 male Sprague-Dawley rats (270-300 g) were assigned to one of five groups on the basis of their core temperature (Tc, 37, 39, 41, 43, or 44 degrees C) at death. Heart rate (HR), mean arterial pressure (MAP), and Tc were monitored during heat stress under alpha-chloralose anesthesia (12.5 mg.ml-1.h-1). At each predetermined Tc, an aortic blood sample was drawn and analyzed for mean plasma concentration of norepinephrine (NE), epinephrine (E), Na+, K+, and lactate. From 41 to 43 degrees C, NE and E rose significantly, and the animals became hyperkalemic and lactacidemic. In a separate study, we quantitated SNA from the greater splanchnic nerve during heat exposure of artificially respired animals anesthetized with pentobarbital sodium (50 mg/kg). MAP, splanchnic SNA, and Tc were recorded. Tc was elevated from 37.0 +/- 0.12 to 41.3 +/- 0.18 degrees C in 70 min by increase of ambient temperature to 38 degrees C in an environmental chamber. Splanchnic SNA was 54 +/- 8 spikes/s at a Tc of 37 degrees C and increased significantly as Tc exceeded 39 degrees C (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Functional and morphological changes in the eccrine sweat gland with heat acclimation.

Three adult male patas monkeys (11-15 kg) were heat acclimated by continuous exposure to an ambient temperature of 33 +/- 1 degree C at 13% relative humidity for 9 mo. During the last month, they were also exposed to 45 degrees C at 10% relative humidity for 4 h/day and 5 days/wk. Before and after 3 wk of acclimation, the animals were given a heat-tolerance test in which rectal (Tre) and mean skin (Tsk) temperatures, heart rate, and sweat rate (msw) were monitored during a 90-min exposure to 45 degrees C heat with 24% relative humidity under lenperone (1.0-1.4 mg/kg im) tranquilization. Maximal in vivo msw was also determined in response to subcutaneous injections (1 and 10% solutions) of methacholine (MCh). Before and after 9 wk and 9 mo of acclimation, sweat glands were dissected from biopsy specimens of the lateral calf, cannulated, and stimulated in vitro with MCh. Morphological measurements of isolated tubules were compared with maximal secretory rates produced by MCh stimulation. Three weeks of acclimation 1) reduced Tre and Tsk and increased msw during the heat tolerance test and 2) significantly increased maximal msw in response to MCh stimulation. Acclimation also increased (P less than 0.05) sweat gland size, as measured by tubular length and tubular volume. Maximal in vitro msw produced by MCh stimulation and msw per unit length of secretory coil also increased significantly. We conclude that heat acclimation increases the size of eccrine sweat glands and that these larger glands produce more sweat. They are also more efficient because they produce more sweat per unit length of secretory coil.

[Technic and long-term results of cryogenic epilation in trichiasis and distichiasis]. / Technik und Langzeitergebnisse der Kryoepilation bei Trichiasis und Distichiasis.

The present paper communicates the technique and results of cryoepilation in 1,690 cases (94% trichiasis and 6% distichiasis). Only nitrogen cryotherapy devices are totally suitable for this, and the spray freezing method is to be preferred. The IKG unit developed by the authors, which has proved successful in particular for tumor therapy, is also ideal for cryoepilation. It generates a very tightly bundled nitrogen spray jet, thus permitting isolated freezing of the lid margin. In about 95% of the cases permanent epilation is achieved without undue trauma. In 5% the condition described by Fraunfelder as "secondary trichiasis" develops. Ocular pemphigoid is not a contraindication to cryotherapy.

[A new device technic for cryotherapy of glaucoma]. / Eine neue Gerätetechnik für die Kryotherapie des Glaukoms.

With nitrogen cryotherapy, the authors achieve lasting normalization of intraocular pressure in more than 90% of their primary glaucoma cases. To accomplish this, the therapeutic parameters (working temperature, diameter of the applicator tip, duration of application, number of application points, applicator contact pressure) must be strictly defined and coordinated. The applicator contact pressure has hitherto been neglected in published data, although it dictates the heat transfer resistance between the applicator and the surface of the bulb and is therefore a major factor influencing the therapeutic effect. A device was therefore developed which indicates the applicator contact pressure continuously during therapy, both optically and acoustically. It renders cryotherapy just as effective as microsurgical methods, with no side-effects.

Effect of cerebrospinal fluid hyperosmolality on sweating in the heat-stressed patas monkey.

Dehydration increases the osmolality of body fluids and decreases the rate of sweating during thermal stress. By localizing osmotic stimuli to central nervous system tissues, this study assessed the role of central stimulation on sweating in a heat-stressed nonhuman primate. Lenperone-tranquilized patas monkeys (Erythrocebus patas n = 5), exposed to 41 +/- 2 degrees C, were monitored for calf sweat rate, rectal and mean skin temperatures, oxygen consumption, and heart rate during infusions (255-413 microliters) of hypertonic artificial cerebrospinal fluid (ACSF) into the third cerebral ventricle. ACSF made hypertonic with NaCl to yield osmolalities of 800 and 1,000 mosmol/kgH2O significantly decreased sweat rate compared with control ACSF (285 mosmol/kgH2O), achieving maximal reductions during infusion of 37 and 53%, respectively. Rectal temperature significantly increased during the recovery period, reaching elevations of 0.69 and 0.72 degrees C, respectively, at 20 min postinfusion. In contrast, ACSF made hypertonic with sucrose (800 mosmol/kgH2O) failed to change sweat rate or rectal temperature during infusion in three animals. Thus, intracerebroventricular infusions of hypertonic ACSF mimicked dehydration-induced effects on thermoregulation. The reduction in heat loss during infusion appeared to depend on an elevation in cerebrospinal fluid [Na+] and not osmolality per se.

Effects of CSF ANG II and AVP on sweating in the heat-stressed patas monkey.

Increasing cerebrospinal fluid [Na+] reduces sweat rate (msw) in the heat-stressed patas monkey (Erythrocebus patas). This study determined the potential role of two neuropeptides, angiotensin II (ANG II) and arginine vasopressin (AVP), in mediating this response. Artificial cerebrospinal fluid, containing either ANG II or AVP, was infused into the third cerebral ventricle of lenperone-tranquilized monkeys (n = 4) exposed to 41 +/- 2 degrees C. Solutions were infused at 16.5 microliters/min for 25 min (total vol approximately 413 microliters). ANG II (1.25, 2.5, 5, and 10 ng/microliters) tended to decrease .msw. However, during infusion, only the decline at 10 min associated with the 1.25-ng/microliters dose (26%) was different (P less than 0.004) from control. This dose elevated (P less than 0.004) core rectal temperature by 1.14 degrees C at 20 min postinfusion. In contrast, AVP (0.5 and 1.5 micrograms/microliters artificial cerebrospinal fluid) had no significant effect on .msw compared with control infusions. Both doses of AVP produced a slight but significant increase in rectal temperature of 0.14 and 0.22 degrees C, respectively, at 20 min postinfusion. In conclusion, the magnitude and time course of the change in .msw with central ANG II suggest that it does not act as the sole mediator of the decline in .msw observed with elevated cerebrospinal fluid [Na+]. The minimal effects produced by third ventricular AVP exclude this route as a means by which AVP could modulate .msw during dehydration.