Iron-induced oxidative DNA damage and its repair in primary rat hepatocyte culture

Iron-overload diseases frequently develop hepatocellular carcinoma. The genotoxic mechanism whereby iron is involved in hepatocarcinogenesis might involve an oxidative process via the intermediate production of reactive oxygen species. This was presently investigated by examining kinetics of formation and repair of DNA base lesions in primary rat hepatocyte cultures supplemented with the iron chelate, ferric nitrilotriacetate Fe-NTA (10 and 100 microM). Seven DNA base oxidation products have been identified in DNA extracts by gas chromatography- mass spectrometry, which showed a predominance of oxidized-purines (8- oxo-guanine, xanthine, fapy-adenine, 2-oxo-adenine) above oxidized pyrimidines (5-OHMe-uracil, 5-OH-uracil, 5-OH-cytosine) in control cultures. All these DNA oxidation products revealed a significant dose- dependent increase at 4 to 48 h after Fe-NTA supplementation, among which fapy-adenine showed the highest increase and 5-OH-cytosine was the least prominent. Involvement of iron in this oxidative process was established by a correlation between extent in DNA oxidation and intracellular level of toxic low molecular weight iron. DNA excision- repair activity was estimated by release of DNA oxidation products in culture medium. All the seven DNA oxidation products were detected in the medium of control cultures and showed basal repair activity. This DNA repair activity was increased in a time- and dose-dependent fashion with Fe-NTA. Oxidized-pyrimidines, among which was 5-OHMe-Uracil, were preferentially repaired, which explains the low levels detected in oxidized DNA. Since oxidized bases substantially differed from one another in terms of excision rates from cellular DNA, specific excision- repair enzymes might be involved. Our findings, however, demonstrate that even though DNA repair pathways were activated in iron-loaded hepatocyte cultures, these processes were not stimulated enough to prevent an accumulation of highly mutagenic DNA oxidative products in genomic DNA. The resulting genotoxic effect of Fe-NTA might be relevant in understanding the hepatocarcinogenic evolution of iron-overload diseases.      

Tissue Inhibitor of Metalloproteinase-1 Concentrations are Attenuated in Peritoneal Fluid and Sera of Women with Endometriosis and Restored in Sera by Gonadotropin-Releasing Hormone Agonist Therapy

Objective: To establish tissue inhibitor of metalloproteinase-1 (TIMP-1) concentrations in peritoneal fluid (PF) and sera of women with endometriosis and compare them to disease-free controls.

Design: Prospective randomized study.

Setting: Academic medical center.

Patient(s): Women with laparoscopically documented endometriosis and disease-free women of reproductive age.

Intervention(s): Peritoneal fluid and sera were collected, and some women received gonadotropin-releasing hormone agonist (GnRH-a) therapy for endometriosis.

Main Outcome Measure(s): Peritoneal fluid and sera TIMP-1 concentrations were measured with a specific RIA.

Result(s): The TIMP-1 concentrations were significantly lower in PF and sera of women with endometriosis compared with disease-free women. The GnRH-a therapy restored serum TIMP-1 concentrations.

Conclusion(s): Aberrant expression and localization of TIMP-1 may derange the proteolytic milieu of the peritoneal cavity and contribute to the etiology and underlying physiologic sequelae associated with endometriosis. Measurement of TIMP-1 in serum may aid in diagnosing endometriosis and assist with monitoring treatment efficacy in women with this disease.     

Prevalence of potentially severe drug-drug interactions in ambulatory patients with dyslipidaemia receiving HMG-CoA reductase inhibitor therapy.

BACKGROUND: Drug-drug interactions (DDIs) are a well known risk factor for adverse drug reactions. HMG-CoA reductase inhibitors ('statins') are a cornerstone in the treatment of dyslipidaemia and patients with dyslipidaemia are concomitantly treated with a variety of additional drugs. Since DDIs are associated with adverse reactions, we performed a cross-sectional study to assess the prevalence of potentially critical drug-drug and drug-statin interactions in an outpatient adult population with dyslipidaemia. METHODS: Data from patients with dyslipidaemia treated with a statin were collected from 242 practitioners from different parts of Switzerland. The medication list was screened for potentially harmful DDIs with statins or other drugs using an interactive electronic drug interaction program. RESULTS: We included 2742 ambulatory statin-treated patients (mean age +/- SD 65.1 +/- 11.1 years; 61.6% males) with (mean +/- SD) 3.2 +/- 1.6 diagnoses and 4.9 +/- 2.4 drugs prescribed. Of those, 190 patients (6.9%) had a total of 198 potentially harmful drug-statin interactions. Interacting drugs were fibrates or nicotinic acid (9.5% of patients with drug-statin interactions), cytochrome P450 (CYP) 3A4 inhibitors (70.5%), digoxin (22.6%) or ciclosporin (cyclosporine) [1.6%]. The proportion of patients with a potential drug-statin interaction was 12.1% for simvastatin, 10.0% for atorvastatin, 3.8% for fluvastatin and 0.3% for pravastatin. Additionally, the program identified 393 potentially critical non-statin DDIs in 288 patients. CONCLUSIONS: CYP3A4 inhibitors are the most frequent cause of potential drug interactions with statins. As the risk for developing rhabdomyolysis is increased in patients with drug-statin interactions, clinicians should be aware of the most frequently observed drug-statin interactions and how these interactions can be avoided.     

Combined midline-transverse surgical approach for severe blunt injuries to the right liver

BACKGROUND: Although nonoperative treatment has been a major advance in the management of liver trauma, emergency surgery is still required for unstable patients. Severe hepatic lesions located in the right lobe, notably juxtahepatic venous injuries, are difficult to access and still carry a high mortality. METHODS: We describe a surgical approach for severe blunt injury to the right liver by a combined midline-transverse incision. This techniques allows simple, easy, and rapid mobilization and compression of the liver to control bleeding. RESULTS: This technique was used in 10 patients with blunt liver trauma, with grade III (n = 2), IV (n = 5), and V (n = 3) injuries. Mean intraoperative blood transfusion required was 21 units. Six patients underwent mandatory anatomic resection, three patients were treated by hepatic suture, and one patient was treated by packing. This patient developed brain death after surgery and was the only mortality. CONCLUSION: This technique is efficient and less cumbersome than shunting approaches.     

Long-term metabolic results after pancreatic resection for severe chronic pancreatitis

HYPOTHESIS: Type and extent of pancreatic resection have little effect on long-term development of diabetes in patients with chronic pancreatitis (CP) considering the distinctive relentless progression of the disease. DESIGN: A case series of consecutive patients included over a 10-year period. Median duration of follow-up was 6.3 years. Follow-up of survivors was at least 5 years (median, 7.7 years). SETTING: A referral center in a university hospital. PATIENTS: All 68 patients (57 men and 11 women) who underwent pancreatic resection for CP during the study period were included. Median age of patients was 44 years. Complete follow-up was obtained for all patients. INTERVENTIONS: Resection procedures included 35 proximal pancreatoduodenectomies (51%), 31 distal pancreatectomies (46%), and 2 total pancreatoduodenectomies (3%). Four patients (6%) received autologous intraportal islet transplants. MAIN OUTCOME MEASURES: Time from surgery to introduction of insulin therapy or death, perioperative morbidity and mortality, and pain control. RESULTS: Fifty-one patients (75%) had experienced acute episodes of CP 5 months to 13 years before resection. Perioperative mortality and morbidity were 1.5% and 21.0%, respectively. Satisfactory long-term pain control was achieved in 61 patients (90%). Actuarial survival was 54% at 10 years and was significantly worse for patients with alcoholic CP (48% vs 78%; P =.04). Diabetes-free survival was 26% at 10 years, with no difference according to type or extent of pancreatic resection. CONCLUSIONS: Pancreatic resection for severe CP is safe and has good long-term results on pain control but is performed late in the course of disease. Earlier resection and islet of Langerhans autotransplantation should be considered for patients who are inexorably heading toward diabetes, regardless of type and extent of resection performed.     

Immunohistochemical expression of DNA repair proteins in familial breast cancer differentiate BRCA2-associated tumors.

PURPOSE: Morphologic and immunohistochemical studies of familial breast cancers have identified specific characteristics associated with BRCA1 mutation-associated tumors when compared with BRCA2 and non-BRCA1/2 tumors, but have not identified differences between BRCA2 and non-BRCA1/2 tumors. Because BRCA1 and BRCA2 genes participate in the DNA repair pathway, we have performed an immunohistochemical study with markers related to this pathway to establish the profile of the three groups. MATERIALS AND METHODS: We have studied two tissue microarrays that include 103 familial and 104 sporadic breast tumors, with a panel of DNA repair markers including ATM, CHEK2, RAD51, RAD50, XRCC3, and proliferating cell nuclear antigen. RESULTS: We found more frequent expression of CHEK2 in BRCA1 and BRCA2 tumors than in non-BRCA1/2 and sporadic tumors. We found absence of nuclear expression and presence of cytoplasmic expression of RAD51 in BRCA2 tumors that differentiate them from other familial tumors. We validated these results with a new series of patient cases. The final study with 253 familial patient cases (74 BRCA1, 71 BRCA2, 108 non-BRCA1/2), and 288 sporadic patient cases, has allowed us to confirm our preliminary results. Because BRCA2 tumors present a specific immunohistochemical profile for RAD51 and CHEK2 markers that is different from non-BRCA1/2 tumors, we have built a multivariate model with these markers that distinguish both tumors with an estimated probability of at least 76%. CONCLUSION: Our results suggest that BRCA2 tumors demonstrate more cytoplasmic and less nuclear RAD51 staining, and increased CHEK2 staining. This pattern may distinguish BRCA2 from familial non-BRCA1/2 tumors.     

Influence of Documented Lead Poisoning on Environmental Modification Programs in Newark,New Jersey

Data from the Newark, New Jersey Childhood Lead Poisoning Program suggest that the major consequence of the program has been early intervention rather than the amelioration of environmental contamination. During 1975 to 1976, the authors investigated housing for 253 black and Hispanic children with blood levels over 60 Mg/100 ml. Of these, 115 had moved or had given incorrect addresses and were lost to follow-up, 22 were in the same homes but did not make themselves available and in 16 instances, the houses were boarded up or had been destroyed by fire. Of the remaining 100 children, 31% suffered from symptoms potentially related to lead poisoning and 57% of the children were still living in the same dwelling in which the c h id was affected. Only one-fourth of the houses had been properly abated, i. e., the problem of environmental lead had been corrected, and one-fourth of the houses were not investigated at all by health authorities. These data support the concern that lead poisoning will not be effectively combated until the environmental issue is fully addressed.     

A new instrument for assessing the quality of studies on prevalence

There are numerous scientific articles of studies on the prevalence of disorders with non-standardised examination and diagnostic protocols. Because their quality is heterogeneous, a new instrument has been developed for the assessment of such studies. The new instrument is based mainly on statistical criteria. The points assigned for each of the main criteria according to the information gained from each paper are summed up to form a Total Quality Score (TQS). The interrater reliability of the instrument was tested by employing Kappa and Interrater Correlation Coefficient (ICC) statistics. The latter was assessed on the results of three independent investigators. The new quality instrument appeared to be easy to use, and the instructions were comprehensible. The ICC_(2,1) for the TQS ranged between 0.94 and 1.00 indicating almost perfect agreement between the investigators. The reliability of the new instrument enables its use for scientific review purposes. In this way, its validity will also be tested. The instrument could be adopted for assessment of scientific articles of studies on the prevalence of disorders in many, similar, scientific areas.