Dog bites are common in many countries and the most common type of animal bites. Despite the high rates, genital trauma, especially scrotal trauma, caused by dog bite is rare, with few cases reported in the literature. We report the successful treatment of testicular rupture due to dog bite. Treatment consisted of orchiectomy with surgical debriment and antibiotics. The diagnosis and management of scrotal injury caused by dog bite are discussed.
Animals ; Anti-Bacterial Agents ; Bites and Stings ; Diagnosis ; Dogs* ; Orchiectomy ; Rupture* ; Scrotum

BACKGROUND: We evaluated the pharmacodynamic and pharmacokinetic properties of rapacuronium, a new non-depolarizing muscle relaxant. METHODS: The EC50 and EC95 values of rapacuronium, vecuronium, and rocuronium were determined on rat hemidiaphragm, and reversal effects were determined using edrophonium or pyridostigmine. In 57 healthy adults, neuromuscular transmission was monitored at the adductor pollicis. Patients received a single dose of succinylcholine (1.0 mg/kg), rapacuronium (1.5 mg/kg), rocuronium (0.6 mg/kg), or mivacurium (0.16 mg/kg). Onset time, clinical duration, recovery index (RI), total duration (TD), train of four (TOF) ratio at over 95% recovery of control first twitch height, cardiovascular effect, and intubation scores were measured. RESULTS: By in vitro study, the EC50 and EC95 of rapacuronium were 4 to 10 fold larger than those of vecuronium and rocuronium, and by clinical study, the onset time of rapacuronium was similar to those of succinylcholine. The clinical duration of rapacuronium was not different from those of succinylcholine and mivacurium. RI and TD of rapacuronium (9.6 +/- 3.5 min and 30.9 +/- 10.7 min) were longer than those of succinylcholine (3.5 +/- 1.1 min and 18.1 +/- 4.4 min) and mivacurium (6.5 +/- 0.9 min and 23.0 +/- 4.4 min) for spontaneous recovery, but not different during reversal by pyridostigmine (5.0microgram/kg). The TOF ratio was increased after pyridostigmine than during spontaneous recovery. Intubation conditions of rapacuronium were similar to those of succinylcholine. Heart rates were significantly increased (15% of control) within 2 min, but not mean arterial pressure after rapacuronium was administration. CONCLUSIONS: Rapacuronium can be considered a valid alternative to succinylcholine and had no observed cardiovascular effect.
Adult ; Animals ; Arterial Pressure ; Edrophonium ; Heart Rate ; Humans ; Intubation ; Neuromuscular Blockade* ; Pyridostigmine Bromide ; Rats ; Succinylcholine ; Vecuronium Bromide

BACKGROUND: MacFarlane and Rosenthal reported a case of acute quadriplegia after nondepolarizing muscular blocking agents in status asthmaticus patient treated with high doses of corticosteroid. Reports regarding the reactions of glucocorticoid treated muscles to neuromuscular blocking agents are sparse and inconsistent. The aims of this study were to examine the degree of muscle atrophy and its effects on sensitivity to neuromuscular blocking agents in relation to the dose and duration of dexamethasone. METHODS: Sixty Sprague-Dawley rats were divided into six groups. They were treated daily with dexamethasone 0.4 mg/kg and 4 mg/kg daily for 1 week or 3 weeks. The two control groups were treated with normal saline. The day after treatment, the dose-response curves of vecuronium were measured using a phrenic nerve-hemidiaphragm preparation. To classify muscle fiber, the diaphragm was stained for myofibrillar adenosine triphosphatase after alkaline and acid preincubation, and a morphometric examination was carried out. RESULTS: The diaphragmatic muscle in rats treated with long term, high dose dexamethasone showed significant atrophy. For the short term, low dose dexamethasone group, the ED50 and ED95 of vecuronium decreased 41.5% and 26.8% compared to those of the control group, respectively (P<0.05). However, the ED50 of vecuronium in the long term, high dose dexamethasone group increased 22.2% compared to that of the control group (P<0.05). CONCLUSION: This study suggests that sensitiviy to vecuronium was not modulated by dexamethasone-induced muscle atrophy. Quantitative changes of receptors at the neuromuscular junction or some anoother process might be responsible for this change.
Adenosine Triphosphatases ; Animals ; Atrophy ; Dexamethasone* ; Diaphragm ; Humans ; Muscles ; Muscular Atrophy ; Neuromuscular Blocking Agents ; Neuromuscular Junction ; Quadriplegia ; Rats* ; Rats, Sprague-Dawley ; Status Asthmaticus ; Vecuronium Bromide

BACKGROUND: Ondansetron, a 5-HT3 receptor antagonist, is widely used for the prevention of postoperative nausea and vomiting. However, the interaction of ondansetron with non-depolarizing muscle relaxants have not been reported until now. Therefore we studied the effects of ondansetron on the neuromuscular block of vecuronium, rocuronium or atracurium in vitro. METHODS: A square wave 0.1 Hz supramaximal stimuli was applied to the phrenic nerve-hemidiaphragm preparation of a rat, and the twitch height response was recorded mechanomyographically. We measured cumulative concentration response curves of vecuronium, rocuronium or atracurium alone and after pretreating with ondansetron (1microgram/ml). We also measured the effects of ondansetron. The EC50's and EC90's of these muscle relaxants alone and after pretreatment with ondansetron were calculated using an inhibitory sigmoid Emax model. RESULTS: Ondansetron depressed the twitch height in a dose-dependent manner, and its potency was lower than the muscle relaxants. The EC50 and EC90 of ondansetron were 14.7microgram/ml and 33.4microgram/ml, respectively. Pretreated ondansetron (1microgram/ml) significantly reduced the EC50's and EC90's of vecuronium, rocuronium and atracurium (P<0.05). CONCLUSIONS: Ondansetron itself may have neuromuscular blocking properties, and it significantly enhances the neuromuscular blocks induced by vecuronium, rocuronium or atracurium.
Animals ; Atracurium* ; Colon, Sigmoid ; Neuromuscular Blockade* ; Neuromuscular Nondepolarizing Agents ; Ondansetron* ; Postoperative Nausea and Vomiting ; Rats* ; Receptors, Serotonin, 5-HT3 ; Vecuronium Bromide*

BACKGROUND: This study was performed to evaluate the presynaptic effects of depolarizing neuromuscular blocking drugs by using slow and fast frequencies of indirect stimulation on partial twitch depression in vitro. METHODS: A rat phrenic nerve hemidiaphragm was dissected and was mounted in an organ bath containing an oxygenated Krebs solution. The phrenic nerve was stimulated supramaximally and the twitch response (0.1 Hz) was stabilized for at least 30 minutes. T200/T1 ratio (twitch height of the 200th stimuli divided by that of the first stimuli) at frequencies of 0.2, 0.5, 1.0, and 2.0 Hz using a drug concentration which provided approximately 20% twitch depression at 0.1 Hz was calculated. To compare T200/T1 ratios with TOF ratios, a 2.0 Hz TOF response was measured immediately after the 200th stimuli at either frequency of stimulation. RESULTS: T200/T1 ratios produced by succinylcholine (SCC) and decamethonium (C10) were located between alpha-bungarotoxin (ABX) and hexamethonium (C6), however, significant differences among the four drugs were found at 2.0 Hz. The propensity for a decrease in T200/T1 ratios at 2.0 Hz might differ from this study: C6 > C10 > SCC > ABX. T200/T1 ratios at 2.0 Hz were not different from TOF ratios. CONCLUSIONS: It is concluded that small doses of C10 have a greater presynaptic activity than that of SCC, when the observed effects in this study were compared with the result of ABX acting predominantly at postsynaptic receptors and C6 acting predominantly at presynaptic receptors.
Animals ; Baths ; Bungarotoxins ; Depression ; Hexamethonium ; Neuromuscular Blockade* ; Neuromuscular Blocking Agents* ; Oxygen ; Phrenic Nerve ; Rats ; Receptors, Presynaptic ; Succinylcholine

BACKGROUND: beta-Bungarotoxin irreversibly changes the presynaptic membrane, hexamethonium acts on the presynaptic nicotinic receptor, and verapamil blocks the ion channels on the presynaptic membrane. The effect of these drugs on twitch height and train of four (TOF) ratio were investigated, as well as the reversal effects of neostigmine, pyridostigmine or 4-aminopyridine (4-AP) on the partial neuromuscular blockade induced by these drugs. METHODS: Square wave, 0.1 Hz supramaximal stimuli or 2 Hz, 0.2 ms train of four stimuli, was applied to the phrenic nerve-hemidiaphragm preparation of the rat, and the twitch height response was recorded mechanomyographically. The cumulative concentration effects and TOF ratios at each point of twitch depression after beta-bungarotoxin, hexamethonium or verapamil were measured. TOF ratios were observed at 75, 50 and 25% of the control twitch height value during observation of the concentration effect. The EC50 and EC95 of beta-bungarotoxin, hexamethonium or verapamil were calculated using an inhibitory sigmoid Emax model. The reversal effect of some doses of neostigmine, pyridostigmine or 4-aminopyridine to the partial neuromuscular block produced by EC50 of beta- bungarotoxin, hexamethonium or verapamil was determined. RESULTS: The EC50 and EC95 of beta-bungarotoxin, hexamethonium and verapamil were 0.0695 and 0.1160 microgram/ml, 1267.0 and 2033.5 microgram/ml and 29.45 and 37.99 microgram/ml respectively. TOF fade was marked with hexamethonium or verapamil but small with beta-bungarotoxin. Neostigmine or pyridostigmine did not reverse the partial neuromuscular block induced by beta-bungarotoxin, hexamethonium or verapamil. However, 4-AP produced a dose-dependent recovery of the twitch response (P < 0.05). CONCLUSIONS: beta-Bungarotoxin, hexamethonium and verapamil produced different degree of TOF fade, and this may be due to different sites of action of these drugs. 4-AP reversed effectively the partialneuromuscular block induced by beta-bungarotoxin, hexamethonium and verapamil, whereas, neostigmine and pyridostigmine did not.
4-Aminopyridine ; Animals ; Bungarotoxins* ; Colon, Sigmoid ; Depression ; Hexamethonium* ; Ion Channels ; Membranes ; Neostigmine ; Neuromuscular Blockade* ; Pyridostigmine Bromide ; Rats* ; Receptors, Nicotinic ; Verapamil*

BACKGROUND: Intravenous anesthetics may modify airway responsiveness. The author investigated the relaxant effect of thiopental, ketamine, and propofol on isolated rat tracheal smooth muscles. METHODS: The trachea of the rat was dissected and cut into 3-mm rings. The rings were mounted in a water-jacked organ bath filled with Krebs solution aerated with 95% O2 and 5% CO2 at 37degreesC. Thiopental, ketamine, and propofol were given randomly to each ring preconstricted with EC50 of acetylcholine from 10(-6) to 10(-3) M. The relaxation response was the tension during anesthetic equilibration, expressed as a percentage of the tension from EC50 of acetylcholine. RESULTS: Thiopental and propofol (10(-5) to 10(-3) M) relaxed acetylcholine-induced contractions in a dose dependent manner (P < 0.05). Ketamine in doses of 10(-5) and 10(-4) M constricted acetylcholine-induced contractions by 3.2% and 16.5% respectively (P < 0.05). But ketamine in a dose of 10(-3) relaxed acetylcholine-induced contractions by 76.4% (P < 0.05). The relaxation of tracheal smooth muscles was greatest in thiopental, and was least in ketamine (P < 0.05). CONCLUSIONS: All three intravenous anesthetics have an excellent relaxation of tracheal smooth muscles in rats, except in doses of 10(-5) and 10(-4) M of ketamine.
Acetylcholine ; Anesthetics, Intravenous ; Animals ; Baths ; Ketamine* ; Muscle, Smooth* ; Propofol* ; Rats* ; Relaxation ; Thiopental* ; Trachea

BACKGROUND: Dantrolene produces skeletal muscle relaxation by a direct action on excitation-contraction coupling, presumably by decreasing the amount of calcium released from the sarcoplasmic reticulum. The mechanism underlying this action is extrajunctional. The aim of this study was to evaluate the pharmacodynamic properties of dantrolene at the neuromuscular junction and the reversal effects of substances as possible dantrolene antagonists in vitro. METHODS: The effects of evoked twitch tension response have been studied on the isolated phrenic nerve hemidiaphragm muscle strips of the rat, using a single twitch (0.1 Hz) and the train of four (TOF; 2 Hz for 2s) stimulation. The maximum effect (E(max)) and TOF ratio at each point of twitch depression after cumulative doses of dantrolene were measured mechanomyographically. The EC(50) and EC(95) of dantrolene were calculated using an inhibitory sigmoid E(max) model. The reversal effect to E(max) after administration of 10 mM of dantrolene was determined by various doses of neostigmine, pyridostigmine or 4-aminopyridine respectively. RESULTS: The E(max) was 76.14% of the initial twitch tension, but the residual twitch tension was remained until five times (10 mM) of the dose for the E(max) was administered. TOF stimulation to the residual twitch tension did not demonstrate any fade. The EC(50) and EC(95) of dantrolene were 0.379 and 3.177 mM respectively. Neostigmine and pyridostigmine produced a transient but incomplete recovery of twitch tension, which rapidly fell to the level of the twitch response before the drugs were given. However, 4-aminopyridine produced a dose-dependent recovery of the twitch response. The addition of neostigmine (0.5 mg/ml) or pyridostigmine (2.5 mg/ml) did not decrease the EC(50) and EC(95) of 4-aminopyridine in reversing the effect of dantrolene. CONCLUSIONS: These RESULTS have demonstrated the evidence that dantrolene did not completely depress the twitch tension, leaving if at nearly 25%, and accompanying TOF response without fade, and that anticholinesterases were ineffective in antagonizing its blockade. However, 4-aminopyridine was effective and may not be related to the propensity for pre- and postjunctional cholinergic receptor blockade at the neuromuscular junction.
4-Aminopyridine ; Animals ; Calcium ; Cholinesterase Inhibitors ; Colon, Sigmoid ; Dantrolene* ; Depression ; Muscle, Skeletal ; Neostigmine ; Neuromuscular Blockade* ; Neuromuscular Junction* ; Phrenic Nerve ; Pyridostigmine Bromide ; Rats ; Relaxation ; Sarcoplasmic Reticulum

BACKGROUND: alpha-Bungarotoxin, decamethonium or lidocaine has a neuromuscular blocking effect. The aim of this study was to evaluate the pharmacodynamic properties of these drugs at the neuromuscular junction and the reversal effects of antagonists in vitro. METHODS: The effects of evoked twitch tension response have been studied on the isolated phrenic nerve hemidiaphragm preparation of the rat, using a single twitch (0.1 Hz) and the train of four (TOF; 2 Hz for 2 s) stimulation. The cumulative concentration effect and TOF ratio at each point of twitch depression after alpha-bungarotoxin, decamethonium or lidocaine were measured mechanomyographically. The EC50 and EC95 of alpha-bungarotoxin, decamethonium or lidocaine were calculated using an inhibitory sigmoid Emax model. The reversal effects of various doses of neostigmine, pyridostigmine or 4-aminopyridine (4-AP) to the partial neuromuscula r block produced by EC50 of alpha-bungarotoxin, decamethonium or lidocaine were determined. RESULTS: The EC50 and EC95 of alpha-bungarotoxin, decamethonium or lidocaine were 0.179 and 0.320 microgram/ml, 17.07 and 26.84 microgram/ml or 76.80 and 105.70 microgram/ml. TOF fade was produced by alpha-bungarotoxin or decamethonium but not by lidocaine. Neostigmine or pyridostigmine did not reverse the partial neuromuscular block induced by alpha-bungarotoxin, decamethonium or lidocaine. However, 4-AP produced a dose-dependent recovery of the twitch response (P < 0.05). CONCLUSIONS: alpha-Bungarotoxin, decamethonium or lidocaine produced different degree of TOF fade, and it means that this may be due to different site of action of these drugs. 4-AP reversed effectively the partial neuromuscular block induced by alpha-bungarotoxin, decamethonium or lidocaine, whereas neostigmine or pyridostigmine did not.
4-Aminopyridine ; Animals ; Bungarotoxins* ; Colon, Sigmoid ; Depression ; Lidocaine* ; Neostigmine ; Neuromuscular Blockade* ; Neuromuscular Junction ; Phrenic Nerve ; Pyridostigmine Bromide ; Rats*

BACKGROUND: Lidocaine, verapamil or a lidocaine-verapamil mixture was effectively applied for blunting extubation during recovery from anesthesia. However, these drugs can enhance neuromuscular blockade and cardiovascular depression. We investigated the neuromuscular and the cardiovascular effect of lidocaine, verapamil or a lidocaine-verapamil mixture before extubation in the recovery from anesthesia. METHODS: We studied ninety nine healthy adult patients (ASA class I or II), excluding the patients with cardiovascular diseases and with factors affecting neuromuscular function. Induction of anesthesia was performed with thiopental sodium 5 mg/kg and fentanyl 0.1 mg, and maintained with O2-N2O (50%)-enflurane (2%). Supramaximal single twitch stimuli (0.1 Hz) were applied to the ulnar nerve and the twitch response of the adductor pollicis was recorded by the Gould TA 240 recorder via a 2 kg Load Cell Strain Gauge modification. After stabilization of the twitch response, mivacurium (0.16 mg/kg) or vecuronium (0.1 mg/kg) was administered intravenously and endotracheal intubation was performed. Twitch heights were spontaneously recovered without a reversal agent from the neuromuscular blockade as a spontaneous group. Pyridostigmine 10 mg and glycopyrrolate 0.2 mg were administered intravenously around the time of 10% recovery of baseline twitch height as a reversal recovery group. At the time of 100% recovery of twitch height, train of four (TOF) stimuli was applied and then lidocaine, verapamil or a lidocaine-verapamil mixture was administered intravenously in both groups. Maximum depression of twitch height and the TOF ratio at this point, recovery index (RI) measured, and mean arterial pressure and pulse rates were measured before and at 2, 5, 10, 20 and 30 min. after the lidocaine-verapamil mixture administration. RESULTS: Twitch heights were depressed slightly after lidocaine, verapamil or a lidocaine-verapamil mixture administration; however, there were no significant differences to compare with the control. TOFratios were unchanged after lidocaine, verapamil or lidocaine-verapamil administration compared at the 100% twitch height recovery. RI indices were not significant between groups in reversal recovery or in spontaneous recovery. Mean arterial pressure was reduced significantly until 20 min after a lidocaine-verapamil mixture administration, pulse rates were increased at 2 min only after a lidocaine- verapamil mixture administration. CONCLUSIONS: Twitch height and TOF ratios were not affected by clinical doses of lidocaine, verapamil or a lidocaine-verapamil mixture. However, mean arterial pressure and pulse rates were changed significantly by a lidocaine-verapamil mixture.
Adult ; Anesthesia ; Arterial Pressure ; Cardiovascular Diseases ; Depression ; Fentanyl ; Glycopyrrolate ; Heart Rate ; Humans ; Intubation, Intratracheal ; Lidocaine* ; Neuromuscular Blockade* ; Pyridostigmine Bromide ; Thiopental ; Ulnar Nerve ; Vecuronium Bromide ; Verapamil*