Inert gas is a group of rare gases with very low activity, their application in medical field has increasingly drawn attentions. It is known that inert gases helium, xenon and argon have protective effects on nervous system and the mechanisms are related to eradicating free radicals, anti-inflammation, suppressing apoptosis, influencing ion channels and so on. Further study on the neuroprotective effect of inert gas will shed light on a new approach to treat neurological diseases.
Argon ; pharmacology ; Helium ; pharmacology ; Neuroprotective Agents ; pharmacology ; Noble Gases ; pharmacology ; Xenon ; pharmacology

BACKGROUND: In this study, we performed one-lung ventilation (OLV) in rabbits to assess the effects of OLV on the VA/Q ratio and the respiratory physiological changes using MIGET. METHODS: Ten male New Zealand white rabbits, weighing 3-4 kg were selected. To perform MIGET, six inactive gases (SF6, krypton, desflurane, enflurane, diethyl ether, acetone) in 500 ml normal saline were injected intravenously. During two-lung ventilation (TLV), and after OLV for 30 minutes, blood was sampled for blood gas analysis and MIGET, hemodynamic variables were measured. For MIGET, the concentrations of the injected inert gases were measured and converted to retention/excretion data; the VA/Q distribution curve was obtained using a computer. RESULTS: Systolic, mean, and diastolic pulmonary pressures were elevated significantly and pulmonary resistance was doubled (P<0.05) in OLV compared to TLV. Blood pH decreased in OLV. The calculated intrapulmonary shunt was 19% and 52%, TLV and OLV, respectively. The analysis of VA/Q using MIGET showed that the VA/Q distribution curve was wider and that the VA/Q area was larger in normal rabbits. And, that intrapulmonary shunt approximated to 11%. In the case of OLV, a significant increase in shunt was observed but no change in the amount of dead space at distribution area, (log SDQ, log SDV) remained the same, whereas the VA/Q distribution curve shifted toward the right. CONCLUSIONS: OLV in rabbits showed severe hypercapnia and hypoxemia leading to a considerable increase in shunt. Because of the wide range of VA/Q distribution in TLV, no significant changes in respiratory variables were observed during OLV.
Anoxia ; Blood Gas Analysis ; Enflurane ; Ether ; Gases ; Hemodynamics ; Humans ; Hydrogen-Ion Concentration ; Hypercapnia ; Krypton ; Lung* ; Male ; Noble Gases ; One-Lung Ventilation ; Rabbits ; Ventilation ; Ventilation-Perfusion Ratio*

BACKGROUND: Endotoxin is a complex lipopolysaccharide molecule situated within the outer membrane of Gram-negative bacteria. Sepsis and acute respiratory failure (ARDS) can be induced by endotoxin. In order to introduce and develop the experimental model of ARDS in sepsis, we induced sepsis with the endotoxin and investigated the change of respiratory pathophysiology during sepsis using a multiple inert gas elimination technique (MIGET). METHODS: Ten New Zealand white rabbits were anesthetized and ventilated with a Harvard apparatus. In 5 rabbits, 2 mg/kg of lipopolysaccaride from E. coli was infused intravenously for 30 min (Toxin group). At 1, 2, 3, and 4 hours after endotoxin infusion, arterial blood gas, and hemodynamic profiles were checked. To perform the MIGET, six inert gases (SF6, krypton, desflurane, enflurane, diethyl ether, acetone) of widely varying solubility were infused peripherally and the excretion and retention data was determined from measurements of inert gas tensions in pulmonary arterial, systemic arterial blood samples and mixd expiratory gas sampling of pre and post septicemia using gas chromatography. We transformed and analysed the data into a V/Q distribution curve to find out the change of V/Q distribution curve. After the experiments, the animals were dissected and the lungs were extracted for wet/dry weight ratio (WW/DW) and microscopic examination. RESULTS: In the Toxin group, the pulmonary arterial pressures were increased and arterial oxygen tensions were decreased after the endotoxin infusion. The lung WW/DW were increased and inflammatory findings were seen in microscopic examination. In the MIGET, shunt, deadspace and log SDQ were increased in the toxin group, though there were wide V/Q distributions in the control group. CONCLUSIONS: We developed a successful endotoxin induced septic animal model, V/Q distribution curve and data using MIGET. The accomplishment of the experiment will not only allow us to better understand pulmonary pathophysiology of endotoxin induced sepsis using MIGET, but it will also contribute to other pulmonary physiology experiments associated with sepsis.
Animals ; Arterial Pressure ; Chromatography, Gas ; Enflurane ; Ether ; Gram-Negative Bacteria ; Hemodynamics ; Krypton ; Lung ; Membranes ; Models, Animal ; Models, Theoretical ; Noble Gases ; Oxygen ; Physiology ; Rabbits ; Respiratory Insufficiency ; Sepsis ; Solubility ; Ventilation-Perfusion Ratio*

The injection of various long-lasting inert gases into the vitreous cavity to flatten and support a detached retina is of proven value. Persistence of the inert gas can be advantageous from the point of view of retinal detachment surgery, but they can cause rising of the intraocular pressure(IOP) to a dangerously high level. So an accurate assessment of IOP in gas-filled eye is important. Previous studies documented that Schiotz tonometry significantly underestimates IOP in the gas-filled rabbit eye, and Goldmann tonometry is more accurate. But in the operating room, Schiotz tonometer is the only device to measure the IOP, so the relationship between the true lOP and the IOP measured by the Schiotz tonometry in the human eye is very important. In this study an attempt was made to find the extent of discrepancy between Schiotz and Goldmann tonometry in the assessment of IOP in the gas-filled human eye. We performed pars plana vitrectomy in 12 human eyes and pars plana vitrectomy with lensectomy in 10 human eyes. Postoperatively fluid-gas exchange was done with 15% perfluoropropane gas(C3F8). The IOP and gas level were checked immediately before fluid-gas exchange and 3hr, 6hr, 12hr, 24hr and 72hr after fluid-gas exchange using Schiotz and Goldmann tonometer. The relationship between IOP measured by Schiotz and Goldmann tonometer was suggested. In phakic and aphakic eyes, Schiotz tonometrry always gave a lower value, and the discrepancy seemed to be greater in the eyes filled with more gas.
Humans* ; Intraocular Pressure* ; Manometry ; Noble Gases ; Operating Rooms ; Retina ; Retinal Detachment ; Vitrectomy

There are many predisposing factors for acute pulmonary edema, namely, left ventricular failure due to cardiac disease or fluid overloading, hypoalbuminemia, pulmonary capillary endothelial damage from bacterial toxins or irritant gases, rare central nervous system injuries pulmonary hyersensitivity reactions, etc. Acute pulmonary edema following operations is a rare complication especially in a patient whose preoperative cardiopulmonary status was within normal limits. We present a case of unilateral pulmonary edema immediately following operation in a 46 year old male patient who had a modified pull-through operation due to tongue cancer and who had no evidence of preoperative cardiopulmonary disorders. The edema was relieved after 9 hours with intensive care of pulmonary edema such as IPPB with Omorphine, diuretics, corticosteroid, asemi-sitting position and frequent tracheal suction.
Bacterial Toxins ; Capillaries ; Causality ; Central Nervous System ; Diuretics ; Edema ; Heart Diseases ; Humans ; Hypoalbuminemia ; Critical Care ; Intermittent Positive-Pressure Breathing ; Male ; Middle Aged ; Noble Gases ; Pulmonary Edema* ; Suction ; Tongue Neoplasms

Panretinal photocoagulation (PRP) has been known to be beneficial in preventing severe visual loss from diabetic retinopathy. Clinical effects of peripheral scatter treatment on diabetic retinopathies were compared with those of PRP in 40 eyes of each groups. In peripheral scatter treatment, equatorial and peripheral fundus was treated with argon blue-green laser or krypton red laser, in 2 sessions with interval of one week. The incidence of maculopathy causing decrease in visual acuity after laser treatment was higher in PRP-treated group than in peripheral scatter treatment group, but changes in visual acuity and fundus findings at last follow-up were not significantly different between PRP-treated and peripheral scatter treatment group (p>O.05). Peripheral scatter treatment was equally affective as PRP in treating diabetic retinopathy with less amount of laser bums and saving post-equatorial fundus.
Argon ; Diabetic Retinopathy* ; Follow-Up Studies ; Incidence ; Krypton ; Light Coagulation ; Visual Acuity

Subretinal neovascular membrane in the macula is a major cause of central visual loss. We reviewed the clinical records, fundus photography, fluorescein angiography of the 172 eyes of 166 patients in order to disclose the causes and clinical characteristics of subretinal neovascular membrane and performed argon and krypton photocoagulation in 22 patients. The common causes of subretinal neovascular membrane are idiopathic neovascular membrane, myopic and senile macular degeneration in order(27.1, 26.5, 22.3% aa). There was no significant difference in changes of visual acuity and extent of subretinal neovascular membrane between treatment and non-treatment groups.
Argon ; Fluorescein Angiography ; Humans ; Krypton ; Light Coagulation ; Macular Degeneration ; Membranes* ; Photography ; Visual Acuity

Cyclodestruction is generally achieved by applying thermal energy across the intact sclera. Commonly employed modalities are ultrasound, cryopexy, diathermy, noncontact laser light and most recently, contact transscleral laser using argon, krypton and Nd:YAG, diode laser. This study was performed to compare the pressure lowering and tissue effects of contact transscleral cyclophotocoagulation(TSCPC) with diode laser using G prode to cyclocryotherapy in rabbit. The results of this study demonstrate a similar intraocular pressure lowering effect of both cyclocryotherapy and contact TSCPC with diode laser using G prode. Histologic studies showed that both TSCPC and cyclocryotherapy are effective anatomic cyclodetructive modalities but in case of TSCPC, less severe destruction of ciliary body was noted. This study indicated that contact TSCPC with diode laser using G probe delivery provieds effective and safe management for eyes with medically and surgically uncontrolled glaucoma compared to cyclocryotheraphy.
Argon ; Ciliary Body ; Diathermy ; Glaucoma ; Intraocular Pressure ; Krypton ; Lasers, Semiconductor* ; Sclera ; Ultrasonography

OBJECTIVETo assess the value of contrast-enhanced ultrasound imaging in monitoring the therapeutic effect of argon-helium cryosurgical treatment of malignant tumors.

METHODSBefore and after argon-helium cryosurgical treatment, 42 patients underwent contrast-enhanced ultrasound imaging, conventional ultrasound imaging and enhanced CT or magnetic resonance imaging (MRI) for examining the number of tumor foci and the size of necrotic areas.

RESULTSA total of 80 tumor lesions were detected by contrast-enhanced ultrasound imaging. Compared with conventional ultrasound imaging, contrast-enhanced ultrasound imaging detected a significantly greater number of tumors and the intratumoral necrotic areas (96 vs 19) as well as a significantly increased mean size of necrotic areas (5.7∓3.6 cm vs 2.8∓1.7 cm), showing no significant differences from the results by enhanced CT and MRI (94 and 5.5∓3.3 cm, P=0.872 and 0.978, respectively). The short-term therapeutic effect of argon-helium cryosurgery evaluated by contrast-enhanced ultrasound imaging were also similar to that assessed by enhanced CT or MRI (P=0.906).

CONCLUSIONContrast-enhanced ultrasound imaging has important values in monitoring malignant tumors during argon-helium cryosurgical treatment and in evaluating the short-term therapeutic effect of the treatment.

Adult ; Aged ; Argon ; Cryosurgery ; methods ; Female ; Helium ; Humans ; Male ; Middle Aged ; Neoplasms ; diagnostic imaging ; surgery ; Treatment Outcome ; Ultrasonography

OBJECTIVETo study the methylation of O-6-methylguanine-DNA methyltransferase (MGMT) and p16 gene in the sputum cells of radon-exposed population. To provide the experimental base for finding the molecular biomarker of the high risk population of the radon-induced lung cancer.

METHODS91 radon-exposed workers were divided into 4 groups, high dosage group (> 120 WLM), middle dosage group (between 60 and 120 WLM), low dosage group (between 30 and 60 WLB) and lower dosage group (between 2 and 30 WLM) according to the accumulated exposure dosage of the radon daughters. The abnormal methylation of p16 and MGMT gene in the sputum cells of the population in the four groups was detected with the methylation specific PCR (MSP).

RESULTSThere was significantly upward trend for the p16 gene methylation rate (0.00%-20.00%), the MGMT gene methylation rate (0.00%-28.00%) and the total methylation rate (0.00%-40.00%) with the increase of the accumulated exposure dosage of the radon daughters (P < 0.01).

CONCLUSIONThe methylation of p16 and MGMT gene is related to the accumulate exposure dosage of the radon daughters.

Carcinogens, Environmental ; adverse effects ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; DNA Methylation ; Dose-Response Relationship, Radiation ; Humans ; Male ; O(6)-Methylguanine-DNA Methyltransferase ; genetics ; metabolism ; Occupational Exposure ; Radon ; adverse effects ; Radon Daughters ; adverse effects ; Sputum ; metabolism