Detection of DNA damage induced by human carcinogens in acellular assays: potential application for determining genotoxic mechanisms

Positive outcomes of in vitro genotoxicity tests may not always occur as a consequence of direct reaction of a compound or a metabolite with DNA. To follow-up positive responses in in vitro tests, we developed two supplemental, cell-free assays to examine the potential of compounds and metabolites to directly damage DNA. Calf thymus DNA was used as the target for the direct detection of adducts by 32P-postlabeling/TLC and electrochemical detection, and alkaline gel electrophoresis was used to detect single-strand breakage of bacteriophage lambda DNA. To show that these assays would detect damage from relevant compounds, we examined nine human carcinogens (aflatoxin B1, busulfan, chlorambucil, cyclophosphamide, diethylstilbestrol, melphalan, 2-naphthylamine, phenacetin and potassium chromate). Each of the nine compounds produced a positive result for one or both endpoints. Using multifraction contact-transfer TLC, we detected 32P-labeled DNA adducts produced by aflatoxin B1, chlorambucil, diethylstilbestrol, melphalan, 2-naphthylamine, and potassium chromate (plus hydrogen peroxide). Aflatoxin B1, diethylstilbestrol and 2-naphthylamine required metabolic activation (induced rat liver S9) to generate DNA adducts. Although potassium chromate alone induced a slight increase in the content of 8-hydroxydeoxyguanosine (a promutagenic adduct produced by reactive oxygen species), addition of hydrogen peroxide greatly increased 8-hydroxydeoxyguanosine levels. The damage to lambda DNA by each human carcinogen (or metabolites), except diethylstilbestrol, was sufficient to generate single-strand breaks after neutral thermal hydrolysis at 70 degrees C. Chromate was a weak inducer of DNA fragmentation, but adding hydrogen peroxide to the reaction mixtures dramatically increased the DNA strand breakage. Our data suggest that these non-routine, acellular tests for determining direct DNA damage may provide valuable mechanistic insight for positive responses in cell-based genetic toxicology tests.     

Long-term results after resection for gallbladder cancer. Implications for staging and management

BACKGROUND: The surgical management of gallbladder cancer is controversial. There is no consensus among surgeons as to the indications for reoperation or radical resection. OBJECTIVE: The purpose of this study was to examine results of reoperation after an incidental finding of gallbladder cancer after cholecystectomy, and results of radical resection in patients with advanced disease. METHODS: A retrospective review of 149 patients with the diagnosis of gallbladder cancer treated from 1985 to 1993 was performed. Fifty-eight patients were explored and 23 underwent resection for cure. Resection included trisegmentectomy in nine patients and bile duct resection in ten patients. Seventeen patients underwent re-exploration after an incidental finding of gallbladder cancer at initial cholecystectomy. RESULTS: Surgical resection is associated with an actuarial 51% 5-year disease-free survival rate, with a median follow-up time of 48 months. Eight patients are alive beyond 50 months. There were no operative deaths; the perioperative morbidity rate was 26%. Nodal status is the most powerful predictor of outcome. Two patients with T4, NO disease are alive without evidence of disease beyond 4 years. Thirteen of the 17 patients (76%) undergoing reoperation after simple cholecystectomy for T2 or T3 tumors had residual disease. CONCLUSIONS: Patients with nodal metastasis beyond the pericholedochal nodes should not be considered for curative resection. Tumors staged T4, NO should be included with stage III disease, and resection should be considered. Re-resection of T2 or T3 tumors after simple cholecystectomy is likely to include residual disease and should thus provide the only chance for long-term survival.     

The lordotic effect of the OSI frame on operative adolescent idiopathic scoliosis patients

STUDY DESIGN: A prospective evaluation of adolescent idiopathic scoliosis patients undergoing operative treatment on the Orthopedic Systems Incorporated (OSI; Jackson) frame. OBJECTIVES: To investigate prospectively thoracic, thoracolumbar, and lumbar sagittal alignments in patients with adolescent idiopathic scoliosis who undergo an instrumented posterior spinal fusion on the OSI frame. SUMMARY OF BACKGROUND DATA: In several studies, it has been shown that patient positioning on various operative frames is an important component of ultimate lumbar sagittal alignment. However, these studies have all concentrated on the lumbar spine, and no sagittal plane alignment data in adolescent idiopathic scoliosis patients have been reported in the thoracic and thoracolumbar junction as it relates to intraoperative positioning, correction maneuvers and correlative postoperative results. METHODS: Thirty-nine patients with operative adolescent idiopathic scoliosis treated with an instrumented posterior spinal fusion on the OSI frame were prospectively evaluated. Standing preoperative, intraoperative, and postoperative long-cassette lateral radiographs were reviewed with regional and segmental Cobb measurements of the thoracic, thoracolumbar junction, and lumbar spine obtained. RESULTS: Thoracic kyphosis (T1-T12) measured +34 degrees before surgery, +28 degrees during surgery, and +30 degrees after surgery, Thus, a statistically significant decrease was noted in thoracic kyphosis secondary to prone positioning on the OSI frame ( P < 0.05). Thoracolumbar spine measurements from T10 to L2 also showed a lordotic trend from +2 degrees before surgery, to -4 degrees during surgery, to -8 degrees after surgery, which was also statistically significant (P < 0.05). Total lumbar lordosis from T12 to S1 remained relatively unchanged from -60 degrees before surgery, to -59 degrees during surgery, to -60 degrees after surgery. However, segmental lumbar lordosis measured from T12 to the lowest instrumented vertebra showed a statistically significant increase in lordosis from -17 degrees before surgery, to -19 degrees during surgery, to -23 degrees after surgery (P < 0.05). Those patients in whom lumbar pedicle screws were used (vs. hooks alone) had the greatest increase in lumbar instrumented lordosis. CONCLUSIONS: Performing adolescent idiopathic scoliosis correction on the OSI frame tends to decrease thoracic kyphosis, increase thoracolumbar lordosis, and increase segmental instrumented lumbar lordosis, while it maintains total lumbar lordosis.     

Australian multicentre phase II trial of paclitaxel in women with metastatic breast cancer and prior chemotherapy

OBJECTIVE: To determine the efficacy and safety of paclitaxel given as a three-hour infusion in patients with metastatic breast cancer which had progressed despite hormonal therapy and/or chemotherapy. DESIGN AND SETTING: Multicentre phase it trial undertaken in five major centres or hospitals in Sydney, Melbourne and Adelaide. PATIENTS AND METHODS: 50 patients with clinically or radiologically measurable or evaluable metastatic breast cancer recruited between March and July 1993. All had received prior chemotherapy, with subsequent disease progression. INTERVENTION: Paclitaxel (Anzatax, Faulding) was given at a dose of 175 mg/m2 intravenously over three hours every three weeks for up to nine courses. MAIN OUTCOME MEASURES: Response rate (partial or complete); duration of progression-free survival; duration of survival; and adverse reactions. RESULTS: Patients had a median age of 51 years; 62% had received at least two prior drug regimens for metastatic breast cancer and 48% had anthracycline-resistant tumours. A median of six paclitaxel courses was given per patient. Overall response rate was 18% (95% confidence interval [95% CI], 9%-31%), with complete responses in four patients (8%). In patients with anthracycline-resistant tumours, response rate was 25% (95% CI, 10%-47%). Response was not influenced by extent of prior treatment. Estimated median progression-free survival was 4.1 months (95% CI, 3.2-6.0 months) and estimated median survival was 6.3 months (95% CI, 6.2-10.3 months). Treatment was well tolerated, with neutropenia the major toxic effect. CONCLUSIONS: Paclitaxel (three-hour infusion) has significant activity in heavily pretreated patients with metastatic breast cancer, including anthracycline-resistant tumours.     

Orbitography with a new non-ionizing water-soluble contrast medium

Metrizamide is a non-ionic water-soluble contrast medium which is isotonic with human blood and tissue fluid at a concentration of 170 mgI/ml. Retrobulbar injection of 3 ml isotonic metrizamide in the muscular conus of rabbits causes slight and inconstant cellulitis, but a similar reaction can also be found after injection of the same amount of saline. It seems probable that the introduction of fluid sufficient to cause an increase in the retrobulbar pressure can cause inflammatory changes in the orbital tissue, and that this is not always caused by the contrast medium itself. Four patients were examined by orbitography with injection of 4 ml isotonic metrizamide. There were no side effects, and the orbitograms showed contrast of good quality. Metrizamide is therefore considered very suitable for orbitography, especially in hospitals where computer-tomography is not yet available.     

Morbidity in alcoholics. Evidence for accelerated development of physical disease in women

The physical disease profiles of 135 female and 736 male inpatient alcoholics, similar in age, social class, and referral pattern, were compared to further clarify the widespread clinical impression that female alcoholics are more illness-prone. Although the women had been drinking hazardously for fewer years, at admission the prevalence of most diseases was similar in men and women. There was, however, an excess of anemia in women and of fatty liver and chronic obstructive lung disease in men. Furthermore, the average duration of hazardous drinking before the first recorded occurrence of almost all illness events was shorter in women, the sex differences being statistically significant for fatty liver, hypertension, obesity, anemia, malnutrition, gastrointestinal hemorrhage, and an ulcer requiring surgery. These findings suggest that the development of physical morbidity in relation to hazardous drinking may be accelerated in women.     

Three cDNA clones encoding mouse transplantation antigens: homology to immunoglobulin genes

We constructed cDNA libraries from poly(A)+ RNA isolated from cell lines of two different inbred strains of mice, and screened the libraries with a cDNA clone encoding a human transplantation antigen. Three cDNA clones were identified, sequenced and found to encode amino acid sequences highly homologous to portions of a known mouse transplantation antigen. Comparison of the cDNA sequences of mouse transplantation antigens with the constant region domains of the mouse immunoglobulin mu gene reveals a striking homology, which suggests that the two genes share a common ancestor. Antibody genes undergo DNA rearrangement during B cell differentiation that are correlated with their expression. In contrast, DNA blots with these cDNA probes suggest that the genes for the transplantation antigens are not rearranged in the genomes of liver or embryo cells, which express these antigens, as compared with sperm cells, which do not express these antigens. In Bam Hl-digested liver DNAs from different inbred strains of mice, 10-15 bands of hybridization were found. Accordingly, the genes encoding the transplantation antigens appear to constitute a multigene family with similar gene numbers in different mice.     

Pituitary responsiveness to gonadotrophin releasing factor (GnRH) in puerperium

Administration of a single dose of Gondotrophin Releasing Factor (GnRF) failed to induce an increase in serum FSH immediately postpartum suggesting pituitary refractoriness. However, multiple injection of GnRF resulted in significant FSH increments but these were less than the FSH responses to a single injection of GnRF in normal menstruating women.