Hypericum androsaemum infusion increases tert-butyl hydroperoxide-induced mice hepatotoxicity in vivo

Increasing evidence regarding free radical generating agents indicates that the sustained production of high levels of reactive oxygen species (ROS) can cause hepatotoxicity. Being a short chain analog of lipid peroxide, tert-butyl hydroperoxide (t-BHP) is metabolized into free radical intermediates by cytochrome P450 in hepatocytes, which initiate lipid peroxidation, glutathione depletion and cell damage. The aim of the present study was to evaluate the putative protective effect of Hypericum androsaemum lyophilised infusion against t-BHP-induced mice hepatotoxicity in vivo, which has already been shown to be antioxidant in vitro. However, the results showed that the oral pretreatment with Hypericum androsaemum infusion (4, 20 and 100 mg/kg) for 4 days before a single intraperitoneal dose of t-BHP (1.8 mmol/kg) potentiated the t-BHP-induced hepatotoxicity. In fact, it was observed a potentiation in the depletion of total glutathione and reduced glutathione (GSH) contents and increase in oxidised glutathione (GSSG) level. Also the histopathological evaluation of the mice livers revealed that the infusion raised the incidence of liver lesions induced by t-BHP. These data do not corroborate any effect of Hypericum androsaemum infusion as hepatoprotector, but rather as a potentiator of hepatotoxicity in the present experimental conditions.     

Response to therapy with interferon alpha-2b and prednisolone in aggressive systemic mastocytosis: report of five cases and review of the literature

Aggressive systemic mastocytosis (ASM) is a hematopoietic neoplasm characterized by infiltration of visceral organs by neoplastic mast cells (MCs) with consecutive organopathy and respective clinical and laboratory findings (so called C-Findings). Whereas, it is generally appreciated that patients with ASM are candidates for pharmacological intervention, no ideal drug or drug combination have been identified yet. One drug proposed to work in ASM is interferon alpha-2b (IFN-alpha2b). However, little is known so far about the quality of responses to IFN-alpha2b and actual response rates. We here report on five ASM patients treated with either a combination of IFN-alpha2b (3x3 million units per week) and prednisolone (n=4), or IFN-alpha2b alone (n=1). During therapy, two of the five patients showed a major response defined by complete resolution of C-Finding(s), one a partial response (partial regression of C-Findings), and one a stable disease (no changes in C-Findings). In one patient, progression to mast cell leukemia was seen after 3 months. In contrast to the other patients, this patient exhibited >10% MCs in his bone marrow (bm) smear at first presentation. In summary, our data confirm beneficial effects of IFN-alpha2b (plus prednisolone) for a group of patients with ASM, whereas patients with mast cell leukemia may require more aggressive therapy. Prospective trials with more patients are now required to further document these drug effects and to better define subgroups of patients with ASM who show good and long-lasting responses to IFN-alpha2b.     

Mitotic catastrophe constitutes a special case of apoptosis whose suppression entails aneuploidy

A conflict in cell cycle progression or DNA damage can lead to mitotic catastrophe when the DNA structure checkpoints are inactivated, for instance when the checkpoint kinase Chk2 is inhibited. Here we show that in such conditions, cells die during the metaphase of the cell cycle, as a result of caspase activation and subsequent mitochondrial damage. Molecular ordering of these phenomena reveals that mitotic catastrophe occurs in a p53-independent manner and involves a primary activation of caspase-2, upstream of cytochrome c release, followed by caspase-3 activation and chromatin condensation. Suppression of caspase-2 by RNA interference or pseudosubstrate inhibitors as well as blockade of the mitochondrial membrane permeabilization prevent the mitotic catastrophe and allow cells to further proceed the cell cycle beyond the metaphase, leading to asymmetric cell division. Heterokarya generated by the fusion of nonsynchronized cells can be driven to divide into three or more daughter cells when Chk2 and caspases are simultaneously inhibited. Such multipolar divisions, resulting from suppressed mitotic catastrophe, lead to the asymmetric distribution of cytoplasm (anisocytosis), DNA (anisokaryosis) and chromosomes (aneuploidy). Similarly, in a model of DNA damage-induced mitotic catastrophe, suppression of apoptosis leads to the generation of aneuploid cells. Our findings delineate a molecular pathway through which DNA damage, failure to arrest the cell cycle and inhibition of apoptosis can favor the occurrence of cytogenetic abnormalities that are likely to participate in oncogenesis.     

Stressor-related impairment of synaptic transmission in hippocampal slices from alpha-synuclein knockout mice

The role of alpha-synuclein (alpha-Syn) has recently received considerable attention because it seems to play a role in Parkinson's disease (PD). Missense mutations in the alpha-Syn gene were found in autosomal dominant PD and alpha-Syn was shown to be a major constituent of protein aggregates in sporadic PD and other synucleinopathies. Under normal conditions, alpha-Syn protein is found exclusively in synaptic terminals. However, the potential participation of alpha-synuclein in maintaining and regulating synaptic efficacy is unknown. We have investigated the excitatory synaptic modulation of alpha-synuclein in CA1 pyramidal neurons, using the in vitro hippocampal slice technique. The 4-aminopyridine-induced increase of both spontaneous excitatory postsynaptic current (EPSC) frequency and amplitude was significantly higher in alpha-Syn wild-type than knockout mice, whereas basal spontaneous EPSC frequency and amplitude was similar in both animals. As the spontaneous synaptic activity was abolished by tetrodotoxin, which indicates that it was a result of action potential-mediated transmitter release from presynaptic terminals, spontaneous EPSC changes observed in alpha-Syn knockout mice suggest that these animals present a modification of synaptic transmission with a presynaptic origin. Presynaptic depression of evoked EPSCs by hypoxia or adenosine was significantly larger in alpha-Syn knockout than in wild-type mice, further supporting the hypothesis of regulation of synaptic transmission by alpha-Syn. Together, these observations indicate that the loss of alpha-Syn reduces synaptic efficacy when the probability of transmitter release is modified. We conclude that alpha-Syn might have important actions on the maintenance of the functional integrity of synaptic transmission and its regulation in hippocampus.     

Splenic mastocytosis: report of two cases and detection of the transforming somatic C-KIT mutation D816V

In the vast majority of patients with systemic mastocytosis (SM), the bone marrow is the primary extracutaneous site of disease. In addition to bone marrow involvement, other visceral organs such as the spleen, liver or the gastrointestinal tract, may also be affected. However, isolated involvement of a single extramedullary organ is rarely seen in SM. We report on two patients with SM with splenic involvement, lack of 'diagnostic' mast cell (MC) infiltrates in the bone marrow, and absence of skin lesions. In one patient, a myelodysplastic syndrome was diagnosed prior to the detection of SM. Both patients presented with massive splenomegaly and multifocal MC infiltrates in splenic tissues. These MCs also expressed CD25 as well as the C-KIT mutation D816V. In consecutive examinations, the mutation was also detected in the bone marrow in both patients suggesting diffuse infiltration with neoplastic cells. In summary, our data show that the spleen can be a primary site of disease in rare cases of SM. Mastocytosis should therefore be considered as a (rare) differential diagnosis in patients with splenomegaly of unknown etiology.     

Chemical stabilization of tetrahydrobiopterin by L-ascorbic acid: contribution to placental endothelial nitric oxide synthase activity

The aim of this study was to characterize the mechanism of the chemical interaction between L-ascorbic acid (ASC) and tetrahydrobiopterin (BH(4)) in vitro and to examine its effect on the activity of endothelial nitric oxide synthase (eNOS) in first trimester human placentae. At room temperature, in Tris-HCl buffer (pH 7.4), both ASC and BH(4) were readily oxidized by dissolved O(2) or H(2)O(2). BH(4) was more sensitive to auto-oxidation, while ASC was more susceptible to oxidation by H(2)O(2). Addition of 36 micromol/l BH(4) to 143 micromol/l ASC increased the initial rate of ASC oxidation 3.2-fold in a catalase-sensitive manner, indicating that enhanced ASC oxidation is partly due to the formation of H(2)O(2). In the presence of catalase, BH(4) still stimulated 1.9-fold the initial rate of ASC oxidation, suggesting that another auto-oxidation product of BH(4), most probably quininoid-BH(2) (qBH(2)), could also stimulate ASC oxidation while itself being reduced back to BH(4). ASC prevented the auto-oxidation of BH(4) in a concentration-dependent fashion, with 3 mmol/l ASC providing an almost complete stabilization of 25 micromol/l BH(4). Importantly, basal eNOS activity in placental microsomes was stimulated 2.5-fold by 0.5 micromol/l BH(4), and 0.5 mmol/l ASC enhanced the BH(4)-stimulation 1.4-fold, with a smaller effect on basal eNOS activity. Taken together, the findings support the notion that the stabilizing action of ASC on BH(4) is related to the ASC-mediated reductive reversal of the auto-oxidation process of BH(4). Moreover, we demonstrated that concentrations of ASC present in the placenta as a common vitamin C supply are sufficient to protect cellular free BH(4) and may contribute to the stimulation of placental eNOS activity.     

Thermal burn fatalities in the workplace,United States, 1992 to 1999

The purpose of this study was to present the epidemiology of thermal burn fatalities in the workplace in the United States between 1992 and 1999. Data on fatal thermal burn injuries in the United States between 1992 through 1999 were obtained from the Bureau of Labor Statistics Census of Fatal Occupational Injuries. Between 1992 and 1999, 1,189 fatal thermal burns occurred in the workplace (0.11 deaths/100,000 workers per year). Mortality increased with age, with those over 65 years of age having the greatest rate of death (0.20/100,000). Workers in the mining industry and transportation and public utilities had the highest rates of fatal thermal burns. Occupational categories with the highest rates included "extractive occupations" (eg, miners, explosives workers) and "transportation and material movers" (eg, truck drivers). The specific occupations with the highest rates were airplane pilots and navigators, furnace, kiln, and oven operators, and firefighters. Most decedents were operating vehicles or involved in "other transportation operations" at the time of the incident. The majority of injurious incidents occurred on "industrial premises" or the "street and highway." Efforts to prevent fatal occupational thermal burn injuries should focus on older workers and those in occupations with frequent exposure to potential sources of thermal injury. Further study of nonfatal thermal burns in the workplace is needed because patterns of fatal burn injury may not reflect patterns of occupational burn injury overall.     

Positive culture in allograft ACL-reconstruction: what to do?

The transmission of disease or infection from the donor to the recipient is always a risk with the use of allografts. We carried out a research study on the behavioural pattern of implanted allografts, which were initially stored in perfect conditions (all cultures being negative) but later presented positive cultures at the implantation stage. Because there is no information available on how to deal with this type of situation, our aim was to set guidelines on the course of action which would be required in such a case. We conducted a retrospective study of 181 patients who underwent an ACL reconstruction using BPTB allografts. All previous bone and blood cultures and tests for hepatitis B and C, syphilis and HIV were negative. An allograft sample was taken for culture in the operating theatre just before its implantation. The results of the cultures were obtained 3–5 days after the operation. We had 24 allografts with positive culture (13.25%) after the implantation with no clinical infection in any of these patients. Positive cultures could be caused by undetected contamination while harvesting, storing or during manipulation before implantation. The lack of clinical signs of infection during the follow-up of our patients may indicate that no specific treatment—other than an antibiotic protocol—would be required when facing a case of positive culture of a graft piece after its implantation.     

Evolution of urticaria pigmentosa into indolent systemic mastocytosis: abnormal immunophenotype of mast cells without evidence of c-kit mutation ASP-816-VAL

Mastocytosis comprises a heterogeneous group of hematological disorders which are morphologically defined by proliferation and accumulation of tissue mast cells in one or more organs. Clinical manifestations of mastocytosis range from disseminated maculopapular skin lesions (= urticaria pigmentosa [UP]) that may spontaneously regress to highly aggressive neoplasms like mast cell leukemia or mast cell sarcoma. Recently, it could be shown that systemic mastocytosis (SM) is a clonal disorder often exhibiting mutations of c-kit, a protooncogene encoding the tyrosine kinase receptor for stem cell factor (SCF). Mutations of c-kit are considered to play a key role in the pathogenesis of mastocytosis. Therefore, we investigated the unique case of a 36 year-old male patient with indolent systemic mastocytosis (ISM) evolving from UP (cutaneous mastocytosis) by means of histology, immunophenotyping and molecular biology. At the time of initial diagnosis the bone marrow showed only a mild diffuse increase in mast cells but compact infiltrates were missing. The serum tryptase levels were normal. Five years later, however, the bone marrow histology displayed patchycompact mast cell infiltrates, which now allowed to establish the diagnosis of an ISM. The serum tryptase levels at this time were markedly elevated. At both time points, mast cells were analyzed by immunohistochemistry using anti-tryptase antibody AA1, by flow cytometry using antibodies against CD2 and CD25, and nested polymerase chain reaction (PCR) on laser-microdissected, single pooled mast cells. Immunohistochemistry revealed strong tryptase-positivity of mast cells in both cutaneous and bone marrow infiltrates. Flow cytometry yielded an aberrant expression of CD2 and CD25 on bone marrow mast cells. However, repeated thorough PCR analysis failed to unveil c-kit mutation in atypical mast cells of skin and bone marrow samples of both dates. These findings clearly show that ISM can evolve from UP. Moreover, our study provides further evidence that the c-kit mutation Asp-816-Val is not invariably present in ISM.     

Therapeutic embolisation for postoperative haemorrhage after total arthroplasty of the hip and knee

We describe three cases of postoperative haemorrhage, two after total hip and one after total knee replacement, treated by percutaneous embolisation. After diagnostic angiography, this is the preferred method for the treatment of postoperative haemorrhage due to the formation of a false aneurysm, after hip or knee arthroplasty. This procedure, carried out under local anaesthesia, has a low rate of complications and avoids the uncertainty of further surgical exploration.