Identification of differentially expressed genes in aflatoxin B1- treated cultured primary rat hepatocytes and Fischer 344 rats

Aflatoxin B1 (AFB1), a mutagen and hepatocarcinogen in rats and humans, is a contaminant of the human food supply, particularly in parts of Africa and Asia. AFB1-induced changes in gene expression may play a part in the development of the toxic, immunosuppressive and carcinogenic properties of this fungal metabolite. An understanding of the-role of AFB1 in modulating gene regulation should provide insight regarding mechanisms of AFB1-induced carcinogenesis. We used three PCR- based subtractive techniques to identify AFB1-responsive genes in cultured primary rat hepatocyte RNA: differential display PCR (DD-PCR), representational difference analysis (RDA) and suppression subtractive hybridization (SSH). Each of the three techniques identified AFB1- responsive genes, although no individual cDNA was isolated by more than one technique. Nine cDNAs isolated using DD-PCR, RDA or SSH were found to represent eight genes that are differentially expressed as a result of AFB1 exposure. Genes whose mRNA levels were increased in cultured primary rat hepatocytes after AFB1 treatment were corticosteroid binding globulin (CBG), cytochrome P450 4F1 (CYP4F1), alpha-2 microglobulin, C4b-binding protein (C4BP), serum amyloid A-2 and glutathione S-transferase Yb2 (GST). Transferrin and a small CYP3A-like cDNA had reduced mRNA levels after AFB1 exposure. Full-length CYP3A mRNA levels were increased. When liver RNA from AFB1-treated male F344 rats was evaluated for transferrin, CBG, GST, CYP3A and CYP4F1 expression, a decrease in transferrin mRNA and an increase in CBG, GST, CYP3A and CYP4F1 mRNA levels was also seen. Analysis of the potential function of these genes in maintaining cellular homeostasis suggests that their differential expression could contribute to the toxicity associated with AFB1 exposure.      

Morphine-induced suppression of saccharin intake is correlated with elevated corticosterone levels

Rats suppress intake of a saccharin conditioned stimulus (CS) when paired with a drug of abuse. This phenomenon, however, is not uniform across all subjects and is greater following exposure to stress and in animals that more readily self-administer drugs of abuse. The present study was designed to examine these individual differences in intake suppression following seven saccharin-morphine pairings. Plasma corticosterone also was evaluated both before and after conditioning in order to determine whether the magnitude of CS suppression is, or is not, related to circulating corticosterone levels. The findings indicated that, while all rats were exposed to the same number of saccharin-morphine pairings, only half of these animals actually suppressed intake of the saccharin CS. Moreover, the results showed that greater suppression of CS intake was associated with higher corticosterone levels at test (r=-0.84, P<0.0001). Taken together, the results demonstrate that individual differences affect not only the reduction in CS intake following taste-drug pairings, but also the associated cue-induced elevation in circulating corticosterone.     

Treatment of osteoarthritis of the knee with valgus deformity by means of varus osteotomy

Nineteen cases of osteoarthritis of the knee with valgus deformity in 17 patients were treated by femoral supracondylar varus osteotomy (17 cases) or by high tibial varus osteotomy (2 cases) over the last 15 years. Fixation was performed using a 95 degrees AO blade-plate in 13 of the femoral osteotomies and a straight plate in the other four. The mean follow-up time was 6.5 years. The valgus deformity was idiopathic in 14 cases, secondary to rheumatoid arthritis in 2 cases and to tibial valgus in one case. The Hospital for Special Surgery (HSS) score was used to evaluate the clinical results: nearly 75% were excellent or good. The causes related to poor results are analyzed regarding indication and surgical technique. It appears that varus osteotomy is an effective procedure for the treatment of osteoarthritis of the knee with valgus deformity, above all in order to alleviate pain, although the operation requires precision, and correct selection of patients is of prime importance.     

Approach to the management of complex hepatic injuries

BACKGROUND: Complex hepatic injuries American Association for the Surgery of Trauma Organ Injury Scale grades IV and V incur high mortality rate ranging from 40 to 80%, respectively. The objective of this study is to assess the clinical experience with an aggressive approach to the management of these, the most complex of hepatic injuries. METHODS: This is a retrospective 6-year study (1992-1997) at an American College of Surgeons urban Level I trauma center of patients sustaining complex hepatic injuries whose interventions included surgery, angiographic embolization, endoscopic retrograde cholangiopancreatography plus biliary stenting and percutaneous computed tomographic-guided drainage. The main outcome measure was survival. RESULTS: A total of 22 patients sustaining complex hepatic injuries; mean age of 26 years (range, 10-52 years), mean Revised Trauma Scale score of 9.9, mean Injury Severity Score of 32 (range, 16-75), American Association for the Surgery of Trauma - Organ Injury Scale grade IV (13 cases); grade V (9 cases). Mean estimated blood loss was 4,600 mL; mean number of units of blood transfused was 15. The patients underwent the following interventions: surgery (n = 22), re-operated (n = 13), mean number of operations 1.6 (range, 1-4), extensive hepatotomy and hepatorrhaphy (n = 17), nonanatomic resection (n = 7), formal hepatectomy (n = 4), packing (n = 10), direct approach to hepatic veins (n = 3); angiographic embolization (n = 15); endoscopic retrograde cholangiopancreatography and stenting (n = 5); computed tomographic guided drainage (n = 6). Mean length of stay in the intensive care unit was 21 days (range, 2-134 days), mean hospital length of stay was 40 days (range, 2-147 days). Overall mortality rate was 14% (3 of 22 cases), hepatic mortality rate was 9% (2 of 22 cases), mortality rate by injury grade was 8% grade IV (1 of 13 cases) and 22% grade V (2 of 9 cases). CONCLUSION: In this select patient population, improvements in mortality rates can be achieved with an aggressive approach to the management of complex hepatic injuries, including surgery, early packing, angiographic embolization, endoscopic retrograde cholangiopancreatography and stenting of biliary leaks, and drainage of hepatic abscesses.     

Bridge to recovery for postcardiotomy failure: is there still a role for centrifugal pumps?

BACKGROUND: Early implantation of centrifugal devices in patients with postcardiotomy cardiogenic shock may provide a bridge to recovery and allow subsequent long-term survival. METHODS: Since January 1989, 62 patients were supported with centrifugal pumps because of failure to wean from cardiopulmonary bypass. Indications were postcardiotomy cardiogenic shock (PCCS) (n = 60), bridge to cardiac retransplantation (n = 1), and right ventricular failure (n = 1). Patients' ages ranged from 23 to 78 years; 40 were men (65%), and 22 were women (35%). Twenty-two patients (35%) had a left ventricular assist device; 9 patients (15%) had a right ventricular assist device; and 31 patients (50%) had a biventricular assist device. Length of support ranged from 1 day to 19 days. RESULTS: Forty-two patients (68%) were weaned successfully; 27 patients survived to discharge (44%). Complications included bleeding (n = 41, 66%), renal failure (n = 28, 45%), and respiratory failure (n = 26, 42%). Currently, 23 patients survived 10 or more years (n = 1), 6 to 10 years (n = 7), 1 to 5 years (n = 10), and less than 1 year (n = 5). CONCLUSIONS: Centrifugal pumps are available, easy to use, and relatively inexpensive. Our experience justifies their continued use as a bridge to recovery for patients with postcardiotomy cardiogenic shock, despite the availability and increasing use of more expensive devices.     

Evaluation of the extent of under-reporting of serious adverse drug reactions: the case of toxic epidermal necrolysis.

INTRODUCTION: Toxic epidermal necrolysis (TEN) is a life-threatening adverse drug reaction (ADR) that is primarily the result of drug exposure (incidence 0.4-1.3 per million person-years). Life-threatening ADRs such as TEN should be reported to ADR monitoring programmes, which collect reports for suspected ADRs and alert the public and medical practitioners to new drug hazards. In Canada, reports are made to the Canadian Adverse Drug Reaction Monitoring Program (CADRMP). OBJECTIVE: To examine the extent of under-reporting for TEN in Canada. DESIGN: A retrospective case series design was used to collect all TEN cases for the period January 1995 to December 2000. METHODS: The CADRMP and 22 burn centres across Canada were contacted for all TEN patients treated during the specified time period. PATIENT GROUPS STUDIED: The study population consisted of patients admitted to burn treatment sites across Canada, patient cases reported to the CADRMP and patient cases recorded by the Canadian Institute for Health Information (CIHI) hospital discharge summaries as the International Classification of Diseases Version 9 Clinical Modification (ICD-9-CM) code 695.1. RESULTS: Twenty-five TEN cases (six fatal) were reported to CADRMP from January 1995 to December 2000. During this period, 14 (63.6%) burn treatment sites reported admission of 250 TEN cases. Hospital discharge summaries using the ICD-9-CM code 695.1 indicated that 4349 cases were admitted to hospital during this time period and it was estimated that 15.5% (n = 674) of these cases were TEN. Using the burn facility data as the denominator, 10% (25 of 250) of TEN cases were reported to CADRMP. Using CIHI data as a denominator, only 4% (25 of 674) of TEN cases were reported to CADRMP. CONCLUSIONS: There is serious under-reporting of TEN. Lack of reporting of life-threatening ADRs can compromise population safety. There is a need to increase awareness of ADR reporting programmes.