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Biomedical subjects

R J Chen

Publications and source records attributed to R J Chen.

At least 19 recordsLinked to original sources
PubMed2001

Cell cycle analysis and detection of proliferative cell nuclear antigen of the endometrium after hormone replacement therapy.

BACKGROUND: To understand the effect of sequential combined hormone replacement therapy (HRT) on the postmenopausal endometrium. METHODS: Sonographic endometrial thickness, endometrial histopathology, flow cytometric cell cycle analysis and the level of proliferative cell nuclear antigen (PCNA) were studied. RESULTS: One hundred and thirty-eight postmenopausal women were enrolled in this study. Among which, 97 women had their endometrium being adequately obtained; the most frequent type of histopathology was normal endometrium (91.8%). Endometrial hyperplasia was found in seven patients (7.2%), including typical simple hyperplasia (n=1, 1%), focal simple hyperplasia (n=5, 5.2%) and complex hyperplasia without atypia (n=1, 1%). The proliferative fractions (PF; S plus G2-M phase) of cells from normal and hyperplastic endometrium of menopausal women after HRT were 8.18 and 8.95%, respectively, which were lower than those from 29 premenopausal women without HRT. The level of PCNA of normal and hyperplastic endometrium in postmenopausal women after HRT was about 80 and 84%, respectively, of that from premenopausal endometrium. CONCLUSIONS: Our study showed the PF of the cell cycle and the level of PCNA were not increased in the menopausal endometrium under HRT as compared to the premenopausal controls.

Aged↗
PubMed2001

Griseofulvin potentiates antitumorigenesis effects of nocodazole through induction of apoptosis and G2/M cell cycle arrest in human colorectal cancer cells.

In this study, we demonstrate that apoptosis and G2/M cell cycle arrest were easily induced by treatment with the oral-antifungal agent, griseofulvin (GF). The mechanisms of GF-induced G2/M arrest were characterized as (a) induction of abnormal mitotic spindle formation, (b) elevation of cyclin B1/cdc2 kinase activity and (c) down-regulation of myt-1 protein expression. On the other hand, caspase 3 activation, Bcl-2 hyperphosphorylation and inhibition of the normal function of Bcl-2 associated with Bax were demonstrated to be the mechanisms of GF-induced apoptosis. DNA fragmentation and flow cytometry analyses demonstrated that combined treatment of GF with the cancer chemotherapeutic agent, nocodazole (ND), strongly potentiates the apoptotic effect and arrest of the G2/M cell cycle in 5 types of human cancer cells, but not in normal human keratinocytes (#76 KhGH). The combined treatment of GF and ND triggered the polymerization of purified tubulin in HT 29 but not in #76 KhGH cells. To further confirm these observations, the therapeutic efficacy was further examined in vivo by treating athymic mice bearing COLO 205 tumor xenografts, with GF (50 mg/kg), ND (5 mg/kg) or GF + ND. Combined treatment of GF and ND significantly enhanced the effect of ND, and led to cessation of tumor growth. These results suggest that chemotherapeutic agents (such as ND) administered in the presence of GF might provide a novel therapy for colorectal cancer.

Animals↗
PubMed2001

Medication errors in anesthetic practice: a survey of 687 practitioners.

PURPOSE: The objectives of this study were to determine: 1) if anesthesiologists had experienced a medication error and 2) to identify causal factors. The perceived value of a Canadian reporting agency for medication errors and improved standards for labels on drug ampoules was also investigated. METHODS: A self-reporting survey was mailed to members of the Canadian Anesthesiologists' Society (n = 2,266). Respondents provided free-text descriptions of medication errors and answered fixed response questions. RESULTS: Surveys from 687 anesthesiologists (30% response rate) revealed that 85% of the participants had experienced at least one drug error or "near miss". Although most errors (1,038) were of minor consequence (98%), four deaths were reported. The commonest error involved the administration of muscle relaxants instead of a reversal agent. "Syringe swaps" (70.4%) and the misidentification of the label (46.8%) were common contributing factors. Anesthesiologists (97.9%) reported that they read the ampoule label "most of the time" although the label colour was an important secondary cue. Approximately half of the participants would report the error if a reporting program existed and 84% agreed that improved standards for drug labels would reduce the incidence of error. CONCLUSIONS: Most anesthesiologists experienced at least one drug error. The commonest error was a "syringe swap" that involved a muscle relaxant. Most errors were of minor consequence, however, serious morbidity and mortality resulted from clearly preventable events. These results support the development of improved standards for drug labels and the establishment of a Canadian reporting program for medication errors.

Anesthesiology↗
PubMed2001

Intra-abdominal pressure monitoring as a guideline in the nonoperative management of blunt hepatic trauma.

BACKGROUND: Nonoperative management has been validated as a standard of care for patients with blunt hepatic trauma. We herein study the correlation of intra-abdominal pressure (IAP) and other clinical parameters to predict the failure of nonoperative management, and attempt to use IAP to determine further therapeutic options. METHODS: During a 9-month period, 25 hemodynamically stable patients sustaining grades III to V blunt hepatic injuries were prospectively studied. They were admitted to the intensive care unit for clinical reevaluation, and hemodynamic and IAP monitoring. If the patient developed an IAP greater than 25 cm H(2)O, then an emergent laparotomy or laparoscopy was performed to achieve hemostasis and decompression of intra-abdominal hypertension (IAH). On the basis of an IAP of 25 cm H(2)O, the correlation between the IAP and an estimated amount of liver-related transfusion, the Pao(2)/Fio(2) ratio and peritoneal signs were analyzed. RESULTS: Of the 25 patients being studied, 20 (80%) had an IAP below 25 cm H(2)O, 1 of whom was found to have a pelvic abscess from an amputated segment of liver. On the other hand, five other patients with an IAP greater than 25 cm H(2)O received decompression and laparoscopic examinations, and one needed an open hepatorrhaphy. In general, though, 19 patients (76%) were successfully treated without operation. All recovered well after different therapeutic regimens; however, two developed liver abscesses, for a morbidity rate of 8% (2 of 25). This analysis revealed a strong association between the IAP value and the presence of peritoneal signs (Phi coefficient = 0.890, p < 0.001), but not in the estimated amount of liver-related transfusion and Pao(2)/Fio(2) ratio. CONCLUSION: This preliminary investigation suggests that IAH or abdominal compartment syndrome can develop while patients receive nonoperative management for grade III to V blunt hepatic injuries. There were no parameters that precisely reflected ongoing hepatic hemorrhage or predicted hemodynamic instability. Although the amount of hepatic hemorrhage was not accurately measured by the IAP, it could be reflected by an increased IAP. During nonoperative management, IAP monitoring may be a simple and objective guideline to suggest further intervention for patients with blunt hepatic trauma. Laparoscopic hepatic evaluation and abdominal decompression may be helpful in this situation.

Abdominal Injuries↗
PubMed2001

Needlescopic, laparoscopic, and open appendectomy: a comparative study.

SUMMARY: The benefits of laparoscopic appendectomy appear to be controversial. Since 1994, several abdominal procedures have been completed by using the needlescopic technique, but there appear to be no prospective studies to demonstrate the perceived benefits of needlescopic appendectomy. The authors compared open, laparoscopic, and needlescopic appendectomy in a randomized fashion with regard to duration of surgery, length of hospitalization, analgesic dosage, and surgery-associated complications. From March to July 1998, 75 patients admitted at the emergency station of the authors' hospital with a final diagnosis of acute appendicitis without tumor formation were randomized to receive one of the three treatment categories: open (OA), laparoscopic (LA), and needlescopic (nLA) appendectomy. Laparoscopic and needlescopic appendectomy were performed by using a three-port technique, although the size of the trocar used varied. There were 26 patients in the OA group, 23 in the LA group, and 26 in the nLA group. The mean operation durations for the OA, LA, and nLA groups were 55.4 +/- 28.0 minutes, 69.1 +/- 48.8 minutes, and 62.3 +/- 26.3 minutes, respectively, and these were not significantly different from one another. The mean number of the analgesic doses (Pethidine 1 mg/kg) required was 1.3 +/- 1.2 mg/kg, 0.5 +/- 0.8 mg/kg, and 0.2 +/- 0.6 mg/kg, respectively. Significant differences were noted when comparing the OA with the LA or nLA groups (OA vs. LA, P = 0.02; OA vs. nLA, P = 0.0002; LA vs. nLA, P = 0.06). The mean oral intake durations were 32.2 +/- 16.9 hours, 21.0 +/- 14.6 hours, and 20.8 +/- 16.4 hours, respectively, after surgery for the OA, LA, and nLA groups, and the between-group differences were statistically significant for the OA versus LA group ( P = 0.004) and for the OA versus nLA group ( P = 0.003). The mean durations of hospitalization for the OA, LA, and nLA groups were 3.6 +/-1.8 days, 2.8 +/- 1.4 days, and 2.4 +/- 0.9 days, and difference was detected between the OA and the nLA groups ( P = 0.02). The OA group rendered a greater wound-complication rate and ileus than did the other two groups, but the differences were not detected between the three categories ( P = 0.065, 0.6935). The result of the current study confirmed that the nLA procedure is a feasible and safe one. The nLA procedure provided substantial advantages over the OA procedure in the contexts of diminished postoperative pain and shorter hospital stay without significant increases in postoperative complication rate or surgical time.

Abdominal Pain↗
PubMed2001

Gallbladder torsion: case report and review of the literature.

Torsion of the gallbladder is a surgical emergency, occurring mainly in the elderly. Female is predominant to male with ratio 3 to 1. Despite its unknown etiology, the anatomical variations in the attachment of gallbladder which occur on the mobile mesentery to the inferior margin of the liver are usually found. When the gallbladder twists around the cystic duct and artery, torsion takes place with ensuing occlusion of the flow of bile and blood. Preoperative diagnosis is difficult to make; however, patients who receive prompt surgical treatment with cholecystectomy always get excellent outcomes. Mortality rate is low with 3% to 5%. Here, we report on elderly male patient with gallbladder torsion at our hospital and review the existing literature.

Aged↗
PubMed2001

Acute appendicitis during pregnancy: a clinical assessment.

BACKGROUND: Acute appendicitis is the most common non-obstetric reason for laparotomy during pregnancy. The purpose of this study was to analyze the characteristics of the clinical presentations and postoperative outcomes of these patients and their fetuses. METHODS: Patients who underwent appendectomies during pregnancy from July 1991 to June 1997 were retrospectively identified. Their ages, clinical presentations, the severity of the inflammatory change in the appendices, and the postoperative complications of these patients and fetuses were recorded and analyzed. Long-term outcomes were confirmed by telephone contact, when possible. RESULTS: Forty-five pregnant women who underwent appendectomies for suspected acute appendicitis were retrospectively reviewed. The histopathological inflammatory change in the appendix was proven in 35 patients (78%). Sixty-three percent of the patients were multiparous, and 86% were in the first 2 trimesters. In the clinical settings, pain and tenderness in the right lower abdominal quadrant were the most common symptoms and signs in presentation. Perioperative administration of ritodrine had no obvious advantage in the prevention of fetal loss. Appendectomy was performed beyond 36 hours of onset of symptoms in 28% of the patients, among whom one-half had gangrenous or perforated appendices. Only one fetus was spontaneously lost in 32 patients with diseased appendices (3%), excluding 3 patients choosing artificial abortion. There was no maternal death in our series. CONCLUSION: The rate of fetal loss due to surgery for acute appendicitis during pregnancy was low. Delay of operation was pertinent to the more-inflammatory changes of the appendix and to the higher maternal complication rate. Early surgical intervention is essential.

Acute Disease↗
PubMed2000

Ketoconazole induces G0/G1 arrest in human colorectal and hepatocellular carcinoma cell lines.

Ketoconazole is an oral-antifungal agent that has been used worldwide in the treatment of some hormone-dependent human cancer. In this study, we demonstrated that ketoconazole (20 microM) induced various types of human cancer cell growth arrest in the G0/G1 phase. Our results revealed that ketoconazole-induced growth arrest was more profound in COLO 205 and Hep G2 (with wild-type p53) than in HT 29 (p53 His(273) mutant) and Hep 3B (with deleted p53) cells. The protein levels of p53, p21/Cip1, and p27/Kip1 were significantly elevated by ketoconazole (10 microM) treatment in COLO 205 but not in HT 29 cells. The ketoconazole-induced G0/G1 phase arrest in COLO 205 cells was attenuated by p53-specific antisense oligodeoxynucleotides (20 microM) treatment. These results suggested that the p53-associated signaling pathway is involved in the regulation of ketoconazole-induced cancer cell growth arrest. By Western blot analysis, we demonstrated that cyclin D3 and CDK4 protein but not other G0/G1 phase regulatory protein levels were decreased by ketoconazole-treatment in both COLO 205 and HT 29 cells. Our study provides the basis of molecular mechanisms for ketoconazole in growth inhibition of human cancer cells and such results may have significant applications for cancer chemotherapy.

Animals↗
PubMed2000

Laparoscopic decompression of abdominal compartment syndrome after blunt hepatic trauma.

Abdominal compartment syndrome (ACS) can occur in a variety of surgical conditions, particularly those with major life-threatening hemorrhage, massive volume resuscitation, prolonged operation times, and coagulopathy. In severely traumatized patients, the incidence of ACS is reported to be as high as 14% to 15% after damage control laparotomies. Although favorable results have been achieved with nonsurgical management of adult blunt hepatic trauma, the failure rates still range from 0% to 19%. Exploratory laparotomy is considered the intervention of choice in patients with blunt hepatic trauma who fail nonsurgical treatment. Expedient abdominal decompression currently is the treatment of choice after ACS. Oliguria, tachypnea, and tachycardia developed in two blunt hepatic trauma patients with grade IV and V injuries while they were receiving nonsurgical treatment. The intra-abdominal pressures measured more than 35 and 25 cm H 2O, respectively. Two patients with grade II and III ACS received laparoscopic examination instead of laparotomy. Their ACS was decompressed effectively via laparoscopy without any adverse effects. Therefore, we suggest that laparoscopy can be used as a safe alternative for the decompression of ACS.

Abdominal Injuries↗
PubMed2000

Combined endoscopic and surgical treatment for the polyposis of Peutz-Jeghers syndrome.

Repeated laparotomy with extensive small bowel resectioning and eventual short-bowel syndrome is a major problem in Peutz-Jeghers syndrome (PJS) patients. This problem is caused by gastrointestinal polyposis with intussusception. A combined surgical and endoscopic approach can assess the extent of the polyposis, and small polyps can be removed by snare polypectomy. This can avert multiple enterotomies and decrease bowel resection segments. We applied an intraoperative colonscope via the enterotomy route in an 20-year-old PJS woman, and successfully removed the other 10 polyps distributed in the whole small bowel. As part of an aggressive approach to the management of polyposis in PJS, complete polypectomy can provide a longer symptom-free interval and remove potentially premaligment polyps.

Adult↗
PubMed2000

Blunt hepatic injury: minimal intervention is the policy of treatment.

BACKGROUND: Many publications recommend nonoperative treatment for stable blunt hepatic injury patients. Unstable hemodynamic status is the only indication for surgery. When operation is indicated, controversies exist regarding which operative procedure will be more beneficial to the patients. The purposes of this study are to compare the results of operative and nonoperative management of patients with blunt hepatic injuries and to identify the optimal surgical approach when surgery is indicated. METHODS: Different prospective protocols of treating adult blunt hepatic injuries were conducted. From 1992 to 1993 (group I), urgent surgery would be performed in the presence of hemoperitoneum. The policy shifted to aggressive nonoperative approach between 1996 and 1997 (group II). The patients from each period were divided into three subgroups. Group A included the patients who received nonoperative treatment in either period. Group B consisted of the patients who received surgery in the first period and nonoperative management in the second period. Group C included the patients who were operated on in either group. Comparisons were made between matched groups. RESULTS: Groups IA and IIA patients had minor injuries and could be successfully treated nonoperatively. The results of groups IB and IIB were similar concerning hospital stay, morbidity, and mortality. Transfusion requirements of group IIB patients were significantly higher (2.2 vs. 1.1 units,p = 0.01) than those of group IB. However, 25 (58%) celiotomies of group IB patients were nontherapeutic. When surgery was indicated, group IC patients had significantly higher liver-related mortality (14 of 49 vs. 3 of 55, p = 0.002). Anatomic resection was performed more frequently in that period. CONCLUSION: Nonoperative treatment significantly decreased the rate of nontherapeutic laparotomy but carried the risks of higher transfusion requirements and delaying operation. When surgery was indicated, the policy of minimal intervention positively affected the patients' outcomes. The goal of surgery should be hemorrhage control rather than resection of the injured liver tissues.

Adult↗
PubMed2000

Factors determining operative mortality of grade V blunt hepatic trauma.

BACKGROUND: Despite recent advances in the management of severe hepatic injuries, the operative mortality rate of grade V hepatic injuries still ranges from 67% to 80%. Grade V hepatic injuries involving the retrohepatic cava or main hepatic veins are almost always lethal, especially those from blunt trauma. The purpose of this study is to understand the risk factors determining operative mortality in grade V blunt hepatic trauma, and to try to improve the surgical management of these injuries. METHODS: A retrospective study was conducted at a medical center that offers services including primary, secondary, and tertiary care. Forty-four patients with grade V blunt hepatic injuries were treated during a 6-year period from January 1, 1991, to December 31, 1996. The operative mortality was compared by a multivariate analysis. RESULTS: Forty-four patients with grade V blunt hepatic injuries were identified. Seven patients had only parenchymal injuries, and the others had vascular and associated parenchymal injuries. Venorrhaphy was used in 37 patients; 29 were treated using a nonshunting approach, and 8 with an atriocaval shunt. The overall mortality rate was 68% (30 of 44), and liver-related mortality was 50% (22 of 44). Univariate analysis revealed that the significant variables affecting operative mortality were initial systolic blood pressure, initial base deficit, the Glasgow Coma Scale, injury type, number of resected segments, and total intraoperative blood loss. Based on forward stepping logistic regression analysis, patients with an initial base deficit of -6 mmol/L or less (relative risk = 17.3), and a total intraoperative blood loss of 5,000 mL or more (relative risk = 23.5) would, significantly, encounter a worsening prognosis. CONCLUSIONS: Initial base deficit and total intraoperative blood loss were the significant factors that determined operative mortality after grade V blunt hepatic trauma. We suggest that prompt resuscitation and expeditious and appropriate surgical management, to control operative blood loss, is the only way to reduce operative mortality in patients with grade V blunt hepatic trauma.

Adolescent↗
PubMed2000

Classification and treatment of pooling of contrast material on computed tomographic scan of blunt hepatic trauma.

BACKGROUND: Pooling of contrast material on computed tomographic (CT) scan represents free extravasation of blood as a result of active bleeding. For patients with blunt hepatic injury, aggressive management such as angiography or celiotomy is usually indicated if this sign is detected. The purposes of this study were to further categorize this CT scan finding and to correlate its characteristics with clinical outcomes. This CT scan classification might be helpful for the selection of appropriate management. METHODS: During a 42-month period, 276 patients with blunt hepatic injury were treated. Two hundred twelve of them were hemodynamically stable after initial resuscitation and underwent abdominal CT scan examination. Pooling of contrast material was detected on the CT scans of 15 patients. The CT scans and medical records were reviewed. Special attention was paid to the presence, location, and character of the extravasated contrast material. RESULTS: The finding of pooling of contrast material on CT scan was categorized into three types according to its location and character. Type I showed extravasation and pooling of contrast material in the peritoneal cavity (six patients). All patients with type I CT scan findings became hemodynamically unstable soon after CT scan examination and required emergent laparotomy. Type II findings showed simultaneous presence of hemoperitoneum and intraparenchymal contrast material pooling (six patients). Four patients with type II CT scan findings required laparotomy for hemostasis. Type III findings showed intraparenchymal contrast material pooling without hemoperitoneum (three patients). All patients with type III CT scan signs remained hemodynamically stable. CONCLUSION: With the use of a high-speed spiral CT scanner, it is possible to predict the necessity of operative management or angiography for patients with blunt hepatic injury before deterioration of hemodynamic status. The presence of pooling of contrast material within the peritoneal cavity indicates active and massive bleeding. Patients with this CT scan finding show rapid deterioration of hemodynamic status. Most of these patients might require emergent surgery. Pooling of contrast material in a ruptured hepatic parenchyma indicates active bleeding. Close monitoring and emergent angiography should be performed. Deterioration of hemodynamic status in these patients usually requires prompt surgical intervention. Intraparenchymal pooling of contrast material with unruptured liver capsule often indicates a self-limited hemorrhage. Patients with this CT scan finding have a high possibility of successful nonoperative treatment.

Adolescent↗