The effects of isoflurane on adrenomedullin-induced haemodynamic responses in pithed rats.

BACKGROUND AND OBJECTIVES: Adrenomedullin is a potent vasodilatory peptide. The mechanisms of adrenomedullin-induced responses are via guanine nucleotide guanosine 5'-triphosphate-binding protein (G-protein)-coupled receptor activation and are similar to those of calcitonin gene-related peptide (CGRP). Previously, we reported that sevoflurane and isoflurane inhibit CGRP-induced haemodynamic responses. The effects of volatile anaesthetics on adrenomedullin-induced haemodynamic responses, however, are unclear. We hypothesized that the volatile anaesthetic isoflurane inhibits adrenomedullin-induced haemodynamic responses. We studied the effects of isoflurane on adrenomedullin-induced haemodynamic responses in pithed rats, which enables us to evaluate the direct cardiovascular effects of drugs without interference from centrally mediated circulatory reflexes. METHODS: Male Wistar rats were pithed by inserting a stainless-steel rod into the spinal cord. Following median sternotomy, a flow probe was placed around the ascending aorta to measure aortic blood flow. Mean arterial pressure and cardiac output were maintained at approximately 100 mmHg and 50 mL min-1, respectively, with continuous infusion of norepinephrine. After 30 min inhalation of isoflurane (1%, or 2%) in oxygen, or only oxygen, adrenomedullin (1, 3, 10 or 30 microg kg-1) was administered intravenously. RESULTS: Adrenomedullin administration induced a transient increase followed by a persistent decrease in mean arterial pressure and cardiac output. Isoflurane (2%) significantly inhibited the initial increase in mean arterial pressure and the later decrease in mean arterial pressure and systemic vascular resistance. CONCLUSION: Isoflurane inhibits adrenomedullin-induced vasodilation and positive inotropic effect in pithed rats. Isoflurane might inhibit the adrenomedullin receptor-mediated response, which is a common pathway for both actions.

Percutaneous radio-frequency mandibular nerve rhizotomy guided by CT fluoroscopy.

We describe a new method for radio-frequency mandibular nerve rhizotomy under CT fluoroscopy. A patient with cancer had severe intractable and drug-resistant pain in his left mandibular region. Because he had an anatomic deformity due to cancer invasion and radiation therapy, we planned a mandibular nerve rhizotomy under CT fluoroscopic imaging. The needle was advanced to the mandibular nerve just caudal to the foramen ovale under real-time CT fluoroscopy, avoiding the cancer region. Pain scores of the patient were reduced after the nerve rhizotomy, without any complications.

The effect of ephedrine and phenylephrine on BIS values during propofol anaesthesia.

BACKGROUND: The purpose of this study was to evaluate the effect of ephedrine and phenylephrine on propofol concentrations and bispectral index during propofol anesthesia. METHODS: General anaesthesia was induced with propofol and was maintained with propofol (4 mg kg-1 h-1) and fentanyl. Vecuronium was used to facilitate the artificial ventilation of the lungs. Patients with systolic blood pressure > 90 mmHg were defined as the control group (n = 16). Patients who had to be treated for larger decreases in arterial blood pressure (systolic blood pressure 60, whereas no patient in the control or phenylephrine groups had bispectral index >60. There were no significant differences in propofol concentrations or cardiac output relative to baseline at 3 or 10 min after the administration of ephedrine or phenylephrine. CONCLUSIONS: Ephedrine increases bispectral index values without decreasing propofol concentrations during general anesthesia.

[A case of water intoxication during transcervical resection of the uterine myoma].

A 28-year-old woman underwent trans-cervical resection (TCR) of the uterine myoma. She had no history of complications except for anemia. Anesthesia was maintained with inhalation anesthesia. After 120 min from introducing the resectoscope, her serum sodium dropped to 86.1 mEq.l-1. But her heart rate and the systolic arterial pressure were stable. She was treated with steroid, mannitol, isotonic saline, and 7% NaHCO3. Soon after the end of the operation, she recovered consciousness. At two hours postoperatively, her serum sodium was 119.6 mEq.l-1. On the 1st postoperative day, her serum sodium returned to the normal range (137 mEq.l-1). We should be aware of asymptomatic water intoxication during TCR.

Intraoperative QRS-interval changes caused by hyperkalaemia in an infant with Arima syndrome.

A one-year-and-ten-months-old male infant with Arima syndrome, a very rare genetic disorder, underwent urgent insertion of a catheter for continuous ambulatory peritoneal dialysis (CAPD) under general anaesthesia. During the procedure he showed QRS-interval changes caused by hyperkalaemia which was successfully treated with calcium gluconate. The management and intraoperative complications of this syndrome are reported and available literature reviewed.

Studies on penem antibiotics. II. In vitro activity of SUN5555, a new oral penem.

The new oral penem antibiotic SUN5555 shows broad antibacterial activity against both aerobic and anaerobic Gram-positive and Gram-negative bacteria. SUN5555 is highly stable against various beta-lactamases. It binds preferentially to the penicillin-binding proteins 2 and 1A of Escherichia coli.

Electron microscopic studies of the effect of ACTH and flavin-adenine dinucleotide on adrenocortical atrophy of rats treated with dexamethasone phosphate.

In a previous paper the authors described the morphologic observations that the concomitant administration of ACTH and flavin-adenine dinucleotide (FAD) to hypophysectomized rats exerted a more potent preventive effect on atrophy of the adrenal cortex of the animals than the single administration of ACTH. The present study was made to electron-microscopically observe the effect of concomitant administration of ACTH and FAD on atrophy of the adrenal cortex induced with the administration of dexamethasone (Dx). The zona fasciculata of the adrenal gland of rats treated with Dx+ACTH+FAD was morphologically closer in cell organelles such as smooth-surfaced endoplasmic reticulum, mitochondria and chylomicrons to that of control animals than the counterpart of animals treated with Dx+ACTH only. The zona fasciculata of the adrenal cortex of animals treated with Dx+FAD was morphologically similar to that of animals treated with Dx only. These findings suggested that FAD would potentiate the adrenocorticotropic action of ACTH through its physiologic action.

Histological studies on the effect of ACTH and flavin adenine dinucleotide on the rat adrenal cortex atrophied by hypophysectomy.

The present study describes the morphological changes in the adrenals of hypophysectomized rats injected 0.03 mg of ACTH and/or 10 mg of FAD intraperitoneally for 5 successive days starting 24 hrs after the operation. The administration of only FAD to intact or hypophysectomized rats showed no morphological change in the adrenal cortex. Simultaneous administration of FAD and ACTH to the hypophysectomized rats is more effective for preventing the atrophy induced than the administration of only ACTH. In these animals, similar morphological observations to those in the control, such as the increased nuclear volume, an increase of clear cells, diminuted numbers of lipid droplets and frequent occurrence of various types of granules, were obtained. FAD seems to be effective, through coexisting with ACTH, for preventing atrophy of the adrenals induced by hypophysectomy.

Electron microscopic studies on the effect of ACTH and flavin adenine dinucleotide on adrenocortical atrophy of hypophysectomized rat.

Electron microscopic observation was made on the outer fasciculata cells in the adrenal cortex of hypophysectomized rats receiving 10 mg of FAD and/or 0.3 mg of ACTH intraperitoneally once a day for 5 consecutive days from 24 hours after hypophysectomy. The simultaneous administration of FAD and ACTH to the hypophysectomized rat was more effective for preventing adrenocortical atrophy induced than the administration of ACTH alone. This effect appeared as clear cells with low electron density. While the characteristics induced by hypophysectomy were the decrease in number of smooth-surfaced endoplasmic reticulum (SER) and mitochondria and also crista of mitochondria being tubular. The clear cells showed a less degree of their characteristic. From this fact, it is considered that the external FAD acts against fasciculata cells in the adrenal cortex of hypophysectomized rats as a coenzyme for flavin enzyme under ACTH and decreases oxidation-reaction in mitochondria and oxidative phosphorilation reaction in SER, being induced by hypophysectomy.