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Biomedical subjects

E Vatashsky

Publications and source records attributed to E Vatashsky.

11 recordsLinked to original sources

The effect of meperidine on the guinea pig extrahepatic biliary tract.

The effect of meperidine on the mechanical activity of isolated guinea pig common bile duct (CBD) and gallbladder was studied in vitro. The effect was found to consist of inhibitory and excitatory phases. The inhibitory phase, characterized by a decrease in the response of the CBD and gallbladder to carbachol and electrical stimulation, was seen with concentrations of 10(-6) M or higher. The excitatory phase, seen at high concentrations of meperidine (5 X 10(-5)-10(-4) M), involved an increase in spontaneous contractions of CBD and in the tone of the gallbladder. Neither effect of meperidine was affected by 0.5 X 10(-5) M naloxone. These data indicate that meperidine acts on the biliary tract by a mechanism different from that associated with the effect of morphine.

Animals

Effect of morphine on the mechanical activity of common bile duct isolated from the guinea pig.

The contractile response of isolated guinea pigs common bile ducts (CBD) to transmural electrical stimulation and the effects of morphine and naloxone was studied. Contractile responses increased as a function of stimulus frequency. In the absence of naloxone morphine inhibited the contractile response to electrical stimulation in a dose-dependent manner. Naloxone prevented the inhibitory effect of morphine on the contractile response to electrical stimulation. We conclude that smooth muscle of the CBD in guinea pig is functional and can contribute to biliary motility, and that opiate receptors exist in nerve elements in the CBD.

Animals

Effect of nalbuphine on intrabiliary pressure in the early postoperative period.

The effect of nalbuphine on common bile duct (CBD) pressure was studied by measurements through T-tubes on the first and second postoperative days after cholecystectomy and choledochotomy. Nalbuphine in a dose of 0.25 mg X kg-1 was injected intramuscularly in 11 patients, and changes in biliary pressure, heart and respiratory rate, blood pressure, and arterial blood gases were recorded during the subsequent four hours. The patients were free of pain, had stable common bile duct pressures and did not have any statistically significant changes in their vital signs. These results are similar to our previous observations during perioperative intravenous injection of nalbuphine. It is suggested that nalbuphine does not significantly change, or even may relax, the sphincter of Oddi, and can therefore be recommended as a safe analgesic in the postoperative period after extrahepatic biliary surgery.

Adult

Mechanism of antagonism by physostigmine of acute flunitrazepam intoxication.

The effect of physostigmine on the loss of consciousness and respiratory depression induced in rabbits by flunitrazepam, 1 mg/kg, was studied to demonstrate whether the restoration of consciousness and respiration rate results from an increase in central cholinergic activity or from an interference by physostigmine with specific binding of flunitrazepam to its receptors. Physostigmine, 0.1-0.4 mg/kg iv, caused a dose-related reversal of consciousness and respiration rate within 15 min of its injection, which lasted 15-30 min depending on the dose. This was associated with peak inhibition of acetylcholinesterase (AChE) in the frontal cortex and medulla, at 15 min, ranging from 35-51%. The analeptic effect of physostigmine in flunitrazepam-treated rabbits was prevented by pretreatment with scopolamine, 1 mg/kg. The effective dose range for physostigmine, 3-12 mumol/kg, is close to concentrations of this agent that inhibit activity in solubilized preparations of AChE from rabbit cortex, 1-3 X 10(-8) M. However, physostigmine, 10(-9) -10(-4) M, failed to displace 3H flunitrazepam from specific binding sites on membranes prepared from rabbit cerebral cortex. It is concluded that physostigmine antagonizes the somnolence and respiratory depression induced by benzodiazepines by restoring cholinergic transmission to normal levels. The effective dose range of physostigmine is small, and serious side effects from overdose can occur as a result of excess cholinergic activity at neuromuscular synapses.

Acetylcholinesterase

"Conscious sedation" for laparoscopy.

End-tidal pCO2, mean arterial blood pressure, heart rate and respiratory rate changes during diagnostic gynecological laparoscopy were studied in 30 healthy women by the technique of "conscious sedation" combined with local anesthesia of the skin and peritoneum. No significant hypercarbia or hypoxia was noted. Patients were discharged from hospital within 6 to 8 h of the laparoscopy; all noted their full satisfaction with this method of anesthesia. "Conscious sedation" appears to be a safe and efficient method for short diagnosis laparoscopies in young, nonobese, otherwise healthy patients in whom full general anesthesia is refused or considered inadvisable.

Adult