The management of labour using continuous lumbar epidural analgesia with 0.2% ropivacaine in a parturient with traumatic brain injury.
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Accidents, Traffic↗
Biomedical subjects
P J Chang
Publications and source records attributed to P J Chang.
Direct tramadol application on sciatic nerve inhibits spinal somatosensory evoked potentials in rats.
We sought to determine the possible neural conduction blockade of tramadol and whether there is evidence of localized neural toxicity with spinal somatosensory evoked potential (SSEP) measurements. Male Wistar rats were used. SSEP, elicited by supramaximally stimulating the hind paw and recorded from the thoracolumbar and the first and second lumbar interspinous ligaments, was monitored. SSEPs were obtained before drug application as the pretreatment baseline and measured every 15 min after treatment for 2 h and at 60-min intervals thereafter until SSEP returned to baseline or for another 4 h. Two small strips of Gelfoam (0.6 x 1.0 cm(2)) soaked with the drug were placed under and over the left sciatic nerve for a 30-min period. Gelfoam was prepared with tramadol hydrochloride (Tramal; the US trade name is Ultram) 5, 2.5, and 1.25 mg, diluted if needed with saline to a total volume of 100 microL (5%, 2.5%, and 1.25%, respectively). The control data were obtained from the right side limb with normal saline by following the same method. Spinal SSEPs were measured after 48 h to detect the late neural damage. The results showed that direct tramadol application on sciatic nerves dose-dependently reduced both the amplitude and conduction velocity of SSEPs when compared with the pretreatment baseline. All SSEPs returned to pretreatment baseline, and no significant changes of SSEP between bilateral limbs were noted at the 48-h measurements. No evidence of irreversible conduction blockade indicative of local neural toxicity was seen. Pretreatment with naloxone 1 mg/kg failed to block the changes of SSEP produced by 2.5% tramadol 100 microL. We conclude that tramadol exerts a local anesthetic-type effect on peripheral nerves.
Analgesics, Opioid↗
Function of the intercistronic region of BRLF1-BZLF1 bicistronic mRNA in translating the zta protein of Epstein-Barr virus.
Zta, a transcription factor encoded by Epstein-Barr virus, is efficiently translated from a BRLF1-BZLF1 bicistronic mRNA. In this study, we demonstrate that inserting a stem-loop structure, which is known to block ribosome scanning, in the 5' region of the intercistronic region does not prevent the translation of a luciferase reporter protein from the bicistronic mRNA fused with the firefly luciferase gene, suggesting that the translation does not involve translation reinitiation. Mutational analyses reveal that the region between nucleotides 86 and 125 (region I) of the intercistronic region is essential for the translation. Meanwhile, the region between nucleotides 126 and 165 (region II) is also important since, without this region, the translation is inefficient. The region I sequence is partially complementary to the sequence between nucleotides 1489 and 1524 of 18S rRNA. This homology is significant, since disrupting the homology reduces the translation efficiency. Furthermore, luciferase is efficiently translated if the entire intercistronic region is replaced with a sequence complementary to the region between nucleotides 1401 and 1560 of the 18S rRNA. We hypothesize that Rta may assist 40S ribosome in recognizing the region I sequence to start a scanning process for Zta translation.
Base Sequence↗
Performance of CT in detection of bowel injury.
OBJECTIVE: The objective of our study was to identify relevant and reliable CT signs of bowel injury, to determine the overall performance of CT in detection of bowel injuries, and to establish the effect of the training level of radiologists on this performance. MATERIALS AND METHODS: Abdominal CT scans of 112 patients with blunt abdominal trauma were prospectively and retrospectively reviewed. Fifty patients had proven bowel injuries (with or without other visceral injuries), whereas 62 patients had no bowel injury and comprised the comparison or control group. Thirty-one of the 62 patients in the comparison group had surgical proof of abdominal but not bowel or mesenteric injuries. The retrospective review of the 112 CT scans was performed randomly and individually by nine radiologists unaware of the diagnosis, including three faculty abdominal radiologists, three senior residents in training, and three junior residents in training. Individual performance and group performance were evaluated by receiver operating characteristic analysis, and interobserver agreement was tested. Individual CT signs as relevant predictors of bowel injury were identified by logistic regression. RESULTS: Relevant predictors of bowel injury included mesenteric infiltration, bowel wall thickening, extravasation of vascular or enteric contrast agent, and the presence free air. In the retrospective blinded review, CT showed good to excellent interobserver reliability for individual CT signs as well as for diagnosis of bowel and visceral injuries. Faculty radiologists tended to diagnose injuries with greater accuracy and confidence, but they showed significantly better performance than residents only in diagnosing duodenal perforation. For the prospective CT diagnosis of bowel injury, CT had a sensitivity of 64%, an accuracy of 82%, and a specificity of 97%. CONCLUSION: Bowel injuries are challenging to diagnose on CT. Radiologists with various levels of experience and expertise can achieve accurate and reproducible results using a variety of CT criteria.
Abdominal Injuries↗
Prognostic significance of arterial phase CT for prediction of response to transcatheter arterial chemoembolization in unresectable hepatocellular carcinoma: a retrospective analysis.
OBJECTIVE: The purpose of this study was to use hepatic arterial phase helical CT to assess tumor vascularity and predict the likelihood of response to transcatheter arterial chemoembolization in patients with hepatocellular carcinoma. MATERIALS AND METHODS: Helical CT findings for 57 patients with hepatocellular carcinoma were classified into one of three patterns of vascularity on the basis of the degree of tumor or liver enhancement during the hepatic arterial phase. Cases in which hypervascular lesions predominated were classified as a type 1 pattern. Cases in which hypovascular lesions predominated were classified as a type 2 pattern. Patients were classified as responders or nonresponders on the basis of the changes of tumor size revealed on CT after three transcatheter arterial chemoembolization treatments. RESULTS: We classified the 57 patients as 37 responders (65%) and 20 nonresponders (35%). A statistically significant correlation between the type 1 hypervascular pattern and response to transcatheter arterial chemoembolization was seen; conversely, the type 2 hypovascular pattern correlated with nonresponse to transcatheter arterial chemoembolization (chi-square = 7.85, p = 0.02). Patients classified as responders lived significantly longer than those classified as nonresponders with 12-, 24-, and 36-month survival rates of 90%, 67%, and 36%, respectively, for responders and 70%, 17%, and 10%, respectively, for nonresponders. CONCLUSION: We found that patients who responded to transcatheter arterial chemoembolization had prolonged survival (p < 0.01). Response correlated closely with tumor vascularity as shown on hepatic arterial phase helical CT.
Antineoplastic Agents↗
The dose effect of propofol on cerebrovascular reactivity to carbon dioxide in rabbits.
BACKGROUND: Propofol has several properties beneficial to intracranial operation such as reduction in cerebral metabolic rate and cerebral blood flow (CBF) in a dose-dependent manner while leaving autoregulation intact. Several studies have demonstrated that the responsiveness of CBF to changes in arterial carbon dioxide tension (PaCO2) is maintained during propofol anesthesia in both humans and animals. These studies showed a significant difference in the CBF-CO2 reactivity slope between awake and propofol anaesthetized groups, but no comparison with different doses of propofol was made. To determine the dose effect of propofol on cerebrovascular CO2 reactivity, we used laser Doppler flowmetry (LDF) to detect the changes of CBF during propofol anesthesia. METHODS: Ten rabbits were studied using LDF on the parietal cortex. After surgical preparation, anesthesia was maintained with 66% N2O in O2, morphine 10 mg/kg and pancuronium. Three experimental conditions were studied sequentially with intravenous administration of the following drugs: (1) normal saline (control), (2) propofol 20 mg/kg/h i.v., (3) propofol 40 mg/kg/h i.v. Mean arterial pressure, rectal temperature and hematocrit were kept constant. The arterial carbon dioxide tension (PaCO2) was adjusted to three levels during each condition: 20-25 mmHg (hypocapnia), 35-40 mmHg (normocapnia) and 45-50 mmHg (hypercapnia). CBF was measured continuously and recorded after the target PaCO2 had been reached. RESULTS: There were no differences among all conditions in mean arterial pressure and heart rate. The changes of CBF as PaCO2 increased at the three different CO2 levels during each of the conditions were significantly different. The slope of CBF-CO2 reactivity among three different propofol doses was not significantly different. CONCLUSIONS: These data indicate that cerebral vasomotor responsiveness to CO2 during propofol anesthesia is preserved and that the slope of CBF-CO2 reactivity is independent of propofol doses as mean arterial blood pressure is maintained.
Anesthetics, Intravenous↗
Storage-phosphor computed radiography versus film radiography in the detection of pathologic periradicular bone loss in cadavers.
OBJECTIVES: The purpose of this study was to compare D-speed film, E-speed film, and the Soredex Digora system with respect to the detection of periradicular pathosis. STUDY DESIGN: Radiographic images of 100 cadaver jaws were made with E-speed film, D-speed film, and the Soredex Digora. Each set of 100 images was interpreted by four observers, with 30 days separating each of three viewing sessions from the next. The presence or absence of pathologic (inflammatory) periradicular bone resorption was determined by histologic examination of the samples. The observer performance was compared with the true histologic findings and evaluated with receiver operating characteristic and corrected receiver operating characteristic analysis. RESULTS: No statistically significant differences were found in diagnostic performance among the three radiographic techniques. In addition, no imaging technique was a good indicator of pathosis as determined by histologic analysis. CONCLUSION: Under the conditions of this study, it was determined that D-speed film, E-speed film, and the Soredex Digora were equivalent diagnostic imaging modalities with regard to the detection of pathologic periradicular bone resorption. No technique predictably indicated inflammatory resorption.
Alveolar Bone Loss↗
Characterization of the BcLF1 promoter in Epstein-Barr virus.
The location of the BcLF1 promoter of Epstein-Barr virus (EBV) has been identified by primer extension, which indicates that the +1 site of the BcLF1 mRNA is located at nucleotide 137676 of the EBV genome. According to deletion analysis, the region upstream from nucleotide -38 is not essential for transcription of BcLF1. A 23 bp region in the promoter, from nucleotide -38 to -16, was identified as necessary for regulating the expression of BcLF1, i.e. the promoter activity is activated by 12-O-tetradecanoylphorbol 13-acetate but is repressed by phosphonoacetic acid. The results presented also demonstrate that the oriLyt sequence in cis is essential for enhancing the expression of BcLF1.
Capsid↗
Role of Rta in the translation of bicistronic BZLF1 of Epstein-Barr virus.
The BZLF1 gene of Epstein-Barr virus (EBV), which encodes a transcription factor, Zta, is transcribed into monocistronic and bicistronic mRNAs from two different promoters during the immediate-early stage of the EBV lytic cycle. It is generally accepted that the Zta protein translated from the monocistronic mRNA profoundly influences the activation of the EBV lytic cycle. In this study, we constructed a plasmid, pCMV-RZLUC, which can transcribe a bicistronic mRNA consisting of BRLF1 and a BZLF1-luc fusion gene under latent conditions. P3HR1 cells transfected with this plasmid produce a luciferase activity which is approximately 17-fold higher than the activity exhibited by pRZLUC, a plasmid incapable of transcribing the bicistronic mRNA. Genetic analyses indicated that mutations in BRLF1 not only can decrease the translation of the fusion gene from the bicistronic mRNA but can also be complemented by a functional BRLF1 gene in cis. This observation implies that the product of BRLF1, Rta, is involved in the translation of the downstream gene. Results presented herein also demonstrate that these mutations cannot be complemented in trans with a plasmid overexpressing Rta, suggesting that the amount of Rta in the vicinity of the intercistronic region may be crucial for the translation. Furthermore, our results correspond to those of previous investigations indicating that the Zta protein can be translated from the bicistronic mRNA and that, similar to the translation of bicistronic ZLUC, mutations in BRLF1 also hinder the translation of Zta from the BRLF1-BZLF1 bicistronic mRNA. Translation of Zta from the bicistronic mRNA may play an essential role in the activation of the EBV lytic cycle.
Animals↗
Frequency and effects of extravasation of ionic and nonionic CT contrast media during rapid bolus injection.
PURPOSE: To determine the frequency and clinical effects of extravasation related to rapid bolus infusion of ionic and nonionic contrast media. MATERIALS AND METHODS: Records of 5,106 computed tomographic studies in adult patients who underwent mechanical bolus injection of contrast medium through a plastic cannula in an upper extremity were retrospectively reviewed. RESULTS: Mean infusion rate was 2.8 mL/sec (range, 1-5 mL/sec). Extravasation occurred in 48 (0.9%) patients, including in four of 928 patients who received the median injection rate (2.5 mL/sec). Injection rate was not correlated with frequency or amount of extravasation. Average age and use of ionic versus nonionic contrast medium were identical in patients with and in those without extravasation. There was no sex difference. Thirty-one patients had extravasation of ionic contrast medium; nine of these had extravasation of at least 50 mL. Seventeen patients had extravasation of nonionic contrast medium; seven of these had extravasation of at least 50 mL. Hyaluronidase infiltration was often used as treatment for larger extravasations (in 10 patients each with extravasation of ionic or nonionic medium). No patient required surgical intervention, and none had severe or permanent long-term effects. CONCLUSION: The frequency of extravasation of contrast medium after mechanical bolus injection is higher than that reported for hand-injection or drip-infusion techniques, but there is no correlation between injection rate and extravasation frequency.
Adult↗
Optimizing contrast enhancement during helical CT of the liver: a comparison of two bolus tracking techniques.
OBJECTIVE: The purpose of this study was to evaluate a recently developed hardware and software system for CT scanning that generates images in real time and switches to helical CT scanning by either a visual cue or a region of interest (ROI) amplitude threshold. SUBJECTS AND METHODS: We randomly and prospectively divided 120 abdominal CT examinations into three groups. Two groups received 75 ml of contrast agent at 1.5 ml/sec. Helical CT scanning began after visualization of the contrast bolus arrival in the hepatic veins (visual cue triggering) (39 patients) or after reaching an ROI threshold (automated ROI threshold triggering) (39 patients). A third group served as a control group (42 patients) and received 150 ml of contrast agent at 1 ml/sec. Quality of hepatic enhancement was assessed objectively and subjectively. Comparisons were made after stratifying each group into three weight classes. RESULTS: Errors occurred in 12 (31%) of 39 examinations in the group with automated ROI threshold triggering. In that group, we found a significantly (p < .04) lower mean hepatic enhancement in two of three weight categories, and a significantly (p < .04) lower mean subjective scan quality in one of three weight categories, than we found in the group with visual cue triggering. CONCLUSION: Optimizing portal venous phase helical CT of the liver after a low-volume bolus of contrast agent and an injection rate of 1.5 ml/sec is best achieved by initiating helical CT scanning after visualizing the contrast bolus arrival within the liver rather than after reaching a preset attenuation threshold.
Adult↗
Subarachnoid fentanyl with diluted small-dose bupivacaine for cesarean section delivery.
BACKGROUND: The use of neuraxial opioid was very popular in recent years, and they may augment the analgesia produced by local anesthetic through direct binding with the spinal opioid receptors. Hemodynamic stability is very important during Cesarean section. Theoretically, the reduction of local anesthetic by addition of fentanyl would provide better hemodynamic stability and good anesthetic status. METHODS: Thirty healthy parturients undergoing Cesarean section were assessed in a randomized fashion. They were divided into two groups. Each subject received 5 mg hyperbaric bupivacaine plus 25 micrograms fentanyl (0.5 ml) and cerebrospinal fluid (CSF) 0.6 ml (Group M + F) or 8 mg hyperbaric bupivacaine plus 0.5 ml of CSF (Group M). The effects of hemodynamic stability, side effects, and complete analgesic duration were observed. RESULTS: It was disclosed that the hemodynamic status was more stable in group M + F. The incidence of nausea and vomiting appeared to be not statistically significant between groups. The incidence of pruritus was apparently higher in group M + F (93.5% vs. 0) but the incidence of shivering was much lower in group M + F (0 vs. 33.3%). The complete analgesic duration was longer in group M + F (146 +/- 47 min vs. 104 +/- 44 min). There were no significant differences in the anesthetic and surgical status, 1-min and 5-min Apgar scores, and the time of regression of sensory level to T10. CONCLUSIONS: The combination of small-dose bupivacaine with fentanyl could provide more stable hemodynamic status, longer postoperative analgesia, and lower incidence of shivering. The incidence of pruritus in group M + F was high, but it was usually mild.
Adult↗
Combination of bupivacaine scalp circuit infiltration with general anesthesia to control the hemodynamic response in craniotomy patients.
BACKGROUND: Sudden and overwhelming increases in blood pressure (BP) and heart rate (HR) during incision of the scalp may give rise to morbidity or mortality in patients with intracranial pathology undergoing neurosurgery. A modification of the method proposed by Labat to abate this circumstantiality was applied in a group of patients receiving craniotomy. The modified method was to combine scalp circuit infiltration of local anesthetic with general anesthesia to control the hemodynamic response to craniotomy. METHODS: Twenty-six patients scheduled to undergo craniotomy were randomly divided into two groups. Patients whose conditions or their current medication that might affect the stability of hemodynamics were excluded. In group A patients (N = 16) 25-30 ml of 0.25% bupivacaine was used for scalp circuit infiltration on the operation side, while in those of group B (N = 10) the same volume of 0.9% normal saline was used. After induction, anesthesia was maintained with 0.6% to 1.2% end-tidal isoflurane (ET-Iso) and 50% N2O in oxygen (N2O:O2 = 2 l/min:2 l/min). The end-tidal CO2 was kept within the range of 25-30 mmHg. BP and HR were recorded every five min before incision and then every two min after incision until one hour after induction. ET-Iso was also recorded every two min throughout a period of sixty min. If the BP and HR increased above 20% of the baseline (10 min before incision), thiopental 2.5 mg/kg and fentanyl 2 micrograms/kg were administered. If hypertension became sustained, the isoflurane concentration was adjusted until an acceptable level was obtained. RESULTS: The mean BP during the surgery was 92 +/- 1 mmHg in group A and 92 +/- 7 mmHg in group B. The difference in BP between incision to 6 min after incision was statistically significant (P < 0.05). The mean HR during surgery was 101 +/- 5 beats/min in group B and 91 +/- 2 beats/min in group A, the difference of which was not statistically significant. All of the patients in group B required a deepened anesthesia to keep the BP and HR within the normal range, but no patient in group A had such need. The average concentration of ET-Iso during the 60 min period was 0.95 +/- 0.12% in group B and 0.41 +/- 0.01% in group A, respectively. The difference was statistically significant (P < 0.05). CONCLUSIONS: Our results showed that scalp circuit infiltration with 0.25% bupivacaine significantly improved the cardiovascular stability and reduced the requirement of isoflurane during craniotomy. The routine use of bupivacaine scalp circuit infiltration in patients undergoing craniotomy should be considered.
Adult↗
Patient-controlled epidural analgesia for postherpetic neuralgia in an HIV-infected patient as a therapeutic ambulatory modality.
A 43-year-old HIV-positive male was referred to our pain clinic one month after his fourth attack of herpes zoster infection. He complained of intermittent intolerable sharp and lancinating pain accompanied by numbness over the inner aspect of the left upper extremity, left anterior chest wall and the back. Physical examination revealed allodynia over the left T1 and T2 dermatomes without any obvious skin lesion. The pain was treated with epidural block made possible by a retention epidural catheter placed via the T2-3 interspace. After the administration of 8 ml of 1% lidocaine in divided doses, the pain was completely relieved for 4 h without significant change of blood pressure or heart rate. A pump (Baxter API) for patient-controlled analgesia (PCA) filled with 0.08% bupivacaine was connected to the epidural catheter on the next day and programmed at a basal rate of 2 ml/h, PCA dose 2 ml, lockout interval 15 min, with an one-hour dose limit of 8 ml. He was instructed to report his condition by telephone every weekday. The pump was refilled with drug and the wound of catheter entry was checked and managed every 3 or 4 days. The epidural catheter was replaced every week. During treatment, the pain intensity was controlled in the range from 10 to 0-2 on the visual analogue scale. He was very satisfied with the treatment and reported only slight hypoesthesia over the left upper extremity in the early treatment period. Epidural PCA was discontinued after 28 days. He did not complain of pain thereafter but reported a slight numb sensation still over the lesion site for a period of time. In conclusion, postherpetic neuralgia in an HIV-infected man was successfully treated with ambulatory therapeutic modality of epidural PCA for 28 days.
Adult↗
Teleradiology for rural hospitals: analysis of a field study.
We compared the accuracy of a low-cost teleradiology system with plain film at a small rural hospital. The comparison was a case-control, paired-comparison study. In total 377 consecutive cases were read prospectively by teleradiology and later by independent interpretation of the plain films. 'Truth' was determined in discrepant cases by further investigation of available records and images. Sensitivity and specificity were determined for each modality, and agreement using the kappa statistic. There was 90% agreement between teleradiology and plain film, with no significant differences. Sensitivities (0.88, 0.89) and specificities (0.98, 0.98) of the two methods were almost identical. McNemar's test indicated no significant differences in the accuracy of the two modalities. We conclude that inexpensive teleradiology for small rural hospitals is equivalent to plain film for radiologists' interpretation.
Case-Control Studies↗
Percutaneous thrombolysis of an infected retroperitoneal hematoma with urokinase.
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Combined Modality Therapy↗
Detection of abnormal parathyroid glands in postoperative patients with recurrent hyperparathyroidism: sensitivity of MR imaging.
OBJECTIVE: The efficacy of MR imaging in identifying abnormal parathyroid glands in patients with recurrent hyperparathyroidism after surgery was investigated. SUBJECTS AND METHODS: Findings on preoperative T1- and T2-weighted MR images in 44 patients with recurrent hyperparathyroidism were prospectively evaluated and compared with surgical/pathologic results in all patients. A blinded retrospective analysis of the MR findings comparing T1- or T2-weighted images alone and in combination for detection of abnormal parathyroid glands also was performed. RESULTS: Seventy-four percent of surgically proved abnormal parathyroid glands were detected prospectively and 65% were detected retrospectively on MR images. The combination of T1- and T2-weighted images increased the sensitivity for detection. The sensitivity for detection of abnormal glands was 72% in the neck and 86% in the mediastinum. The sensitivities for detecting parathyroid adenomas (80%) and hyperplastic glands (69%) were not significantly different. There was no threshold volume for detection of lesions with MR imaging. Both intrathyroid parathyroid adenomas were missed on MR images. Abnormal glands could not be differentiated from lymph nodes on MR images in three cases. CONCLUSION: MR imaging is a useful technique for detecting abnormal parathyroid glands preoperatively in patients with recurrent hyperparathyroidism after surgery. The combination of T1- and T2-weighted images increases the sensitivity for detection.
Adult↗
Wanted: new model for teleradiology.
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Computer Communication Networks↗