[Cellular mechanisms of carotid body chemoreception].
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Acetylcholine↗
Biomedical subjects
W Tan
Publications and source records attributed to W Tan.
Radioimmunoassay for serum gastrin in Singapore Chinese.
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Adult↗
Epidural anesthesia: effective analgesia in aortoiliofemoral arteriography.
The efficacy of epidural anesthesia for control of pain experienced by patients undergoing peripheral arteriography was studied in 77 patients. In 70 patients, arteriographic studies were completely painless. Two patients experienced severe pain, while five felt different degrees of limited pain and/or burning sensation. Arteriograms in the 77 patients were excellent because the analgesia allowed injection of large volumes of contrast, the patients did not move during the injection because of motor block, and finally the sympathetic block probably resulted in peripheral vasodilatation. We believe that epidural anesthesia represents the method of choice in the control of pain during arteriographic examinations of the lower extremities.
Anesthesia, Epidural↗
Diagnosis of urine extravasation after renal transplantation.
Urine extravasation in the early postoperative period after renal transplantation is a serious complication requiring expedient surgical intervention. Whereas clinical and laboratory findings are inconclusive, radiologic diagnostic studies have definite value. Routine ultrasound and radioisotope studies were performed on 111 renal transplant patients. In the eight who developed urine extravasation, ultrasound and/or radioisotope studies identified the extravasation in seven cases. Four of the eight were studied by intravenous pyelography and another two were studied by cystography. All results were positive. We recommend use of radioisotope and ultrasound studies for routine postoperative screening with invasive techniques reserved for inconclusive cases.
Adolescent↗
The interaction of the Bainbridge and Bezold-Jarisch reflexes in the conscious dog.
Experiments were undertaken to determine the efferent path of the Bainbridge reflex and to investigate the interaction of the Bainbridge reflex with the Bezold-Jarisch reflex in conscious, chronically instrumented dogs. The Bainbridge reflex was elicited by distending the left atrium by inflating a chronically implanted balloon catheter. The Bezold-Jarisch reflex was elicited using chemical stimulation of left ventricular receptors with infusions of veratridine (0.1-0.8 micrograms/kg/min) into the left circumflex coronary artery. Heart-rate responses to left atrial balloon inflation were compared before and after either beta-1 antagonism with metoprolol or cholinergic antagonism with atropine, and before and during left ventricular receptor stimulation with intracoronary veratridine. Left atrial balloon inflation alone caused a significant increase in heart rate (70.1 +/- 5 bpm), left atrial pressure (14 +/- 3 mmHg) and mean arterial blood pressure (10 +/- mmHg). Heart-rate responses to left atrial distension were inhibited, but not abolished by either cholinergic or beta-1 antagonism. Left atrial distension after both cholinergic and beta-1 antagonism abolished the heart-rate response to balloon inflation. These results indicate that the efferent component of the Bainbridge reflex has both a vagal and a sympathetic component in conscious dogs. Left atrial distension during simultaneous left ventricular receptor stimulation resulted in a significantly decreased tachycardia than did left atrial distension alone (26 +/- 3 bpm compared to 68 +/- 8 bpm in the control experiments). In addition, the slope of the heart rate vs left atrial pressure relationship was significantly inhibited by left ventricular receptor stimulation (1.8 +/- 0.2 bpm/mmHg compared to 5.7 +/- 0.3 bpm/mm Hg in the control experiments). There were no significant differences in either the left atrial pressure or arterial blood pressure changes between the two groups. These data suggest an interaction between these two reflexes that may be occurring in the central nervous system.
Animals↗
Acute baroreflex resetting and its control of blood pressure in an open loop model.
Acute baroreflex resetting has been quantitatively studied in anesthetized dogs. Carotid sinuses were isolated bilaterally and carotid sinus conditioning pressure (CPcsp) was set at nine different levels for 20 min over a range of from 40 to 200 mm Hg. Over this range of 160 mm Hg in CPcsp, the magnitude of baroreflex resetting of set point pressure (Psp), threshold pressure (Pth) and BP50 was 32.0 +/- 5, 43.3 +/- 6 and 39.6 +/- 6 mm Hg, respectively. The extent of resetting was a non-linear function of the level of CPcsp. There is less resetting at high CPcsp. The average extent of resetting is only about 25%. In contrast to this small degree of resetting, a profound inverse relationship between the baseline pressure and the conditioning pressure was observed at the end of the conditioning period for each CPcsp. In addition, we also observed an attenuation in the buffering capacity of the baroreflex at very high or very low CPcsp. Vagotomy and aortic section did not alter baroreflex resetting. This data indicates that the baroreflex is capable of monitoring the absolute level of blood pressure during acute resetting in addition to buffering transient disturbances in arterial pressure. Based upon the results of the present experiments, the concept that acute baroreflex resetting results in an inability of the baroreflex to monitor the absolute level of arterial pressure does not appear to be valid.
Animals↗
Evaluation of percutaneous endoscopic gastrostomy in a university hospital.
BACKGROUND/AIMS: Percutaneous endoscopic gastrostomy (PEG) has become a commonly performed procedure to provide nutritional support for chronically ill patients. The aim of this study was to review the safety and results of PEG in a teaching hospital. METHODOLOGY: A retrospective review of 44 patients who underwent PEG procedure. The indication was long-term enteral feeding in patients who were unable to maintain adequate nutrition by mouth with an otherwise functioning gut. The most common primary diagnosis was cerebrovascular accident (17 patients). All patients were unable to swallow. RESULTS: There were six (13.6%) minor complications, and two mortalities from peritonitis (4.5%). The most common complication was gastrostomy site infection, which did not require exchange of the feeding tube. CONCLUSIONS: PEG is a useful means of providing nutrition in patients unable to swallow without the necessity for laparotomy and general anesthesia. This method provides an adequate avenue for enteral alimentation in selected patients and is relatively safe. Careful attention to the technique of insertion is important to prevent leakage or bowel perforation.
Adolescent↗