Hemophilia A pseudoaneurysm in a patient with high responding inhibitors complicating total knee arthroplasty: embolization: a cost-reducing alternative to medical therapy

Joint hemorrhages are very common in patients with severe hemophilia. Inhibitors in patients with hemophilia are allo-antibodies that neutralize the activity of the clotting factor. After total knee replacement, rare intra-articular bleeding complications might occur that do not respond to clotting factor replacement. We report a 40-year-old male with severe hemophilia A and high responding inhibitors presenting with recurrent knee joint hemorrhage after bilateral knee prosthetic surgery despite adequate clotting factor treatment. There were two episodes of marked postoperative hemarthrosis requiring extensive use of substitution therapy. Eleven days postoperatively, there was further hemorrhage into the right knee. Digital subtraction angiography diagnosed a complicating pseudoaneurysm of the inferior lateral geniculate artery and embolization was successfully performed. Because clotting factor replacement therapy has proved to be excessively expensive and prolonged, especially in patients with inhibitors, we recommend the use of cost-effective early angiographic embolization.

Ontogeny of mRNA abundance of nuclear receptors and nuclear receptor target genes in young cattle

After birth the development of appropriate detoxification mechanisms is important. Nuclear receptors (NR), such as constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor-alpha (PPARalpha), retinoid receptors (RAR, RXR), and NR target genes are involved in the detoxification of exogenous and endogenous substances. We quantified abundances of hepatic mRNA of NR and several NR target genes (cytochromes, CYP; cytochrome P450 reductase, CPR; UDP-glucuronosyl transferase, UDP) in calves at different ages. Gene expression was quantified by real-time RT-PCR. Abundance of mRNA of CAR and PXR increased from low levels at birth in pre-term calves (P0) and full-term calves (F0) to higher levels in 5-day-old calves (F5) and in 159-day-old veal calves (F159), whereas mRNA levels of PPARalpha did not exhibit significant ontogenetic changes. RARbeta mRNA levels were higher in F5 and F159 than in F0, whereas no age differences were observed for RARalpha levels. Levels of RXRalpha and RXRbeta mRNA were lower in F5 than in P0 and F0. Abundance of CYP2C8 and CYP3A4 increased from low levels in P0 and F0 to higher levels in F5 and to highest levels in F159. Abundance of CPR was transiently decreased in F0 and F5 calves. Levels of UGT1A1 mRNA increased from low levels in P0 and F0 to maximal level in F5 and F159. In conclusion, mRNA levels of NR and NR target genes exhibited ontogenetic changes that are likely of importance for handling of xeno- and endobiotics with increasing age.

Surface expression and functional characterization of alpha-granule factor V in human platelets: effects of ionophore A23187, thrombin, collagen, and convulxin

Factor V (FV) present in platelet alpha-granules has a significant but incompletely understood role in hemostasis. This report demonstrates that a fraction of platelets express very high levels of surface-bound, alpha-granule FV on simultaneous activation with 2 agonists, thrombin and convulxin, an activator of the collagen receptor glycoprotein VI. This subpopulation of activated platelets represents 30.7% +/- 4.7% of the total population and is referred to as convulxin and thrombin-induced-FV (COAT-FV) platelets. COAT-FV platelets are also observed on activation with thrombin plus collagen types I, V, or VI, but not with type III. No single agonist examined was able to produce COAT-FV platelets, although ionophore A23187 in conjunction with either thrombin or convulxin did generate this population. COAT-FV platelets bound annexin-V, indicating exposure of aminophospholipids and were enriched in young platelets as identified by the binding of thiazole orange. The functional significance of COAT-FV platelets was investigated by demonstrating that factor Xa preferentially bound to COAT-FV platelets, that COAT-FV platelets had more FV activity than either thrombin or A23187-activated platelets, and that COAT-FV platelets were capable of generating more prothrombinase activity than any other physiologic agonist examined. Microparticle production by dual stimulation with thrombin and convulxin was less than that observed with A23187, indicating that microparticles were not responsible for all the activities observed. These data demonstrate a new procoagulant component produced from dual stimulation of platelets with thrombin and collagen. COAT-FV platelets may explain the unique role of alpha-granule FV and the hemostatic effectiveness of young platelets. (Blood. 2000;95:1694-1702)

Epidermal growth factor receptor inhibitors plus chemotherapy in non-small-cell lung cancer: biologic rationale for combination strategies

Chemotherapy continues to play an essential role in the treatment of most stages of non-small-cell lung cancer (NSCLC). In fact, within the past 5 years, this role has greatly expanded into adjuvant therapy for early-stage resected disease. Likewise, agents targeting the epidermal growth factor receptor (EGFR), particularly the tyrosine kinase inhibitors gefitinib and erlotinib, have proven to be clinically active in patients with advanced-stage NSCLC. Because of these findings, it is logical to expect that combinations of these 2 classes of antineoplastic agents would prove more efficacious than either one alone. Yet 4 large randomized phase III trials of chemotherapy with or without an EGFR tyrosine kinase inhibitor in unselected patients with advanced-stage NSCLC, altogether totaling > 4000 patients, did not demonstrate improvement in clinical outcomes with the combination. Whether these negative results will be reproduced in ongoing combination studies of chemotherapy plus monoclonal antibodies directed against EGFR remain to be determined. Herein, we review recent preclinical and clinical data addressing this topic and explore the biologic rationale for developing new combination strategies based on patient selection by molecular and clinical factors, or by pharmacodynamic parameters.

Two alpha subunits and one beta subunit of meprin zinc-endopeptidases are differentially expressed in the zebrafish Danio rerio

Meprins are members of the astacin family of metalloproteases expressed in epithelial tissues, intestinal leukocytes and certain cancer cells. In mammals, there are two homologous subunits, which form complex glycosylated disulfide-bonded homo- and heterooligomers. Both human meprin alpha and meprin beta cleave several basement membrane components, suggesting a role in epithelial differentiation and cell migration. There is also evidence that meprin beta is involved in immune defence owing to its capability of activating interleukin-1beta and the diminished mobility of intestinal leukocytes in meprin beta-knockout mice. Here we show for the first time by reverse transcription PCR, immunoblotting and immunofluorescence analyses that meprins are expressed not only in mammals, but also in the zebrafish Danio rerio. In contrast to the human, mouse and rat enzymes, zebrafish meprins are encoded by three genes, corresponding to two homologous alpha subunits and one beta subunit. Observations at both the mRNA and protein level indicate a broad distribution of meprins in zebrafish. However, there are strikingly different expression patterns of the three subunits, which is consistent with meprin expression in mammals. Hence, D. rerio appears to be a suitable model to gain insight into the basic physiological functions of meprin metalloproteases.

The alpha and beta subunits of the metalloprotease meprin are expressed in separate layers of human epidermis, revealing different functions in keratinocyte proliferation and differentiation

The zinc endopeptidase meprin (EC 3.4.24.18) is expressed in brush border membranes of intestine and kidney tubules, intestinal leukocytes, and certain cancer cells, suggesting a role in epithelial differentiation and cell migration. Here we show by RT-PCR and immunoblotting that meprin is also expressed in human skin. As visualized by immunohistochemistry, the two meprin subunits are localized in separate cell layers of the human epidermis. Meprin alpha is expressed in the stratum basale, whereas meprin beta is found in cells of the stratum granulosum just beneath the stratum corneum. In hyperproliferative epidermis such as in psoriasis vulgaris, meprin alpha showed a marked shift of expression from the basal to the uppermost layers of the epidermis. The expression patterns suggest distinct functions for the two subunits in skin. This assumption is supported by diverse effects of recombinant meprin alpha and beta on human adult low-calcium high-temperature keratinocytes. Here, beta induced a dramatic change in cell morphology and reduced the cell number, indicating a function in terminal differentiation, whereas meprin alpha did not affect cell viability, and may play a role in basal keratinocyte proliferation.

Increased lipopolysaccharide-induced tumour necrosis factor-alpha, interferon-gamma and interleukin-10 production in atopic dermatitis

BACKGROUND: Atopic dermatitis (AD) is based on a genetic predisposition, but environmental factors may trigger skin inflammation. According to the hygiene hypothesis, decreased exposure to microbial products in early childhood does not allow sufficient maturation of the immune system that is associated with an increased risk of atopic sensitization. OBJECTIVES: The effect of lipopolysaccharide (LPS) on the cytokine production of peripheral blood mononuclear cells (PBMC) of AD patients and nonatopic controls was studied. PATIENTS AND METHODS: PBMC were isolated from heparinized blood of 10 patients with AD and 10 nonatopic individuals, suspended in culture medium and stimulated with LPS. Cytokine levels in the supernatants were measured by immunoassays. Results Upon stimulation with LPS, PBMC from AD patients produced significantly higher amounts of tumour necrosis factor-alpha, interferon-gamma and interleukin (IL)-10 compared with control PBMC. LPS stimulation blocked the increased spontaneous production of IL-4 and IL-5 by PBMC from AD patients, but had no effect on IL-13 production. CONCLUSIONS: These results demonstrate that the effects of LPS stimulation depend on both the type of cytokine and the origin of PBMC. Endotoxin exposure is suggested to modulate the disease course of AD.

Therapeutical potential of direct thrombin inhibitors for atherosclerotic vascular disease

Adverse cardiovascular events are the consequence of a molecular chain reaction at the site of vulnerable plaques. Key players are platelets and coagulation factors that are activated following plaque rupture and often cause arterial obstruction. Thrombin, a plasma serine protease, plays a role in hemostasis of coagulation as well as in thrombosis and cell growth, leading to restenosis and atherosclerosis. Interesting and promising new molecules, the direct thrombin inhibitors, have been shown to be as effective as the combination of glycoprotein IIb-IIIa inhibitors and heparin for the prevention of arterial thrombosis. Until recently, direct thrombin inhibitors could be applied only parenterally; therefore, therapy was limited to hospitalized patients. As a result of recent drug development, orally active direct thrombin inhibitors are now available and have been evaluated for the long-term treatment of venous thrombosis and arterial fibrillation. Due to their specific pharmacodynamic characteristics by binding directly to thrombin--and thus inhibiting platelet aggregation and fibrin generation--these novel drugs may also have therapeutic potential for the treatment of atherothrombotic disease and its complications such as myocardial infarction, stroke or limb ischemia.

Oxidative stress and damage in liver, but not in brain, of Fischer 344 rats subjected to dietary iron supplementation with lipid-soluble [(3,5,5-trimethylhexanoyl)ferrocene]

Accumulation of iron probably predisposes the aging brain to progressive neuronal loss. We examined various markers of oxidative stress and damage in the brain and liver of 3- and 24-month-old rats following supplementation with the lipophilic iron derivative [(3,5,5-trimethylhexanoyl)ferrocene] (TMHF), which is capable of crossing the blood-brain barrier. At both ages, iron concentration increased markedly in the liver but failed to increase in the brain. In the liver of TMHF-treated young rats, levels of alpha- and gamma-tocopherols and glutathione (GSH) were also higher. In contrast, the brain displayed unaltered levels of the tocopherols and GSH. Malondialdehyde (MDA) level was also higher in the cerebrospinal fluid (CSF) and the liver but not in the brain. In old rats, the absence of an increase in iron concentration in the brain was reflected by unaltered concentrations of GSH, tocopherols, and MDA as compared to that in untreated rats. In the aging liver, concentrations of GSH and MDA increased with TMHF treatment. Morphological studies revealed unaltered levels of iron, ferritin, heme oxygenase-1 (HO-1), nitrotyrosine (NT), or MDA in the brains of both young and old rats treated with TMHF. In contrast, TMHF treatment increased the level of HO-1 in Kupffer cells, NT in hepatic endothelial cells, and MDA and ferritin in hepatocytes. Although these results demonstrated an increase in the biochemical markers of oxidative stress and damage in response to increasing concentrations of iron in the liver, they also demonstrated that the brain is well protected against dietary iron overload by using iron in a lipid-soluble formulation.

Anti-inflammatory properties of alpha- and gamma-tocopherol

Natural vitamin E consists of four different tocopherol and four different tocotrienol homologues (alpha,beta, gamma, delta) that all have antioxidant activity. However, recent data indicate that the different vitamin E homologues also have biological activity unrelated to their antioxidant activity. In this review, we discuss the anti-inflammatory properties of the two major forms of vitamin E, alpha-tocopherol (alphaT) and gamma-tocopherol (gammaT), and discuss the potential molecular mechanisms involved in these effects. While both tocopherols exhibit anti-inflammatory activity in vitro and in vivo, supplementation with mixed (gammaT-enriched) tocopherols seems to be more potent than supplementation with alphaT alone. This may explain the mostly negative outcomes of the recent large-scale interventional chronic disease prevention trials with alphaT only and thus warrants further investigation.

Reduced hippocampal anisotropy related to anteriorization of alpha EEG in schizophrenia

Dysfunctions of the hippocampus have been suggested to be related to schizophrenia, and reduced connectivity with other brain regions may be a key for the pathophysiology. The aim of this study was to investigate the effect of white matter anomalies in the hippocampus, as a sign of altered connectivity, on the brain electrical activity. We investigated seven first episode schizophrenic patients and seven age, gender and education-matched controls with diffusion tensor imaging and resting EEG. Fractional anisotropy was computed based on diffusion tensor imaging data for the right and left hippocampus for both groups. No group differences were found in hippocampal fractional anisotropy, EEG spectral power and topography. However a significant correlation was found between more anterior alpha activity and lower fractional anisotropy of both hippocampi in schizophrenics, but not in controls. More anterior alpha activity has been described in schizophrenia. We conclude that this feature might depict a group of schizophrenic patients with reduced hippocampal connectivity.

Cortical and subcortical correlates of electroencephalographic alpha rhythm modulation

Neural correlates of electroencephalographic (EEG) alpha rhythm are poorly understood. Here, we related EEG alpha rhythm in awake humans to blood-oxygen-level-dependent (BOLD) signal change determined by functional magnetic resonance imaging (fMRI). Topographical EEG was recorded simultaneously with fMRI during an open versus closed eyes and an auditory stimulation versus silence condition. EEG was separated into spatial components of maximal temporal independence using independent component analysis. Alpha component amplitudes and stimulus conditions served as general linear model regressors of the fMRI signal time course. In both paradigms, EEG alpha component amplitudes were associated with BOLD signal decreases in occipital areas, but not in thalamus, when a standard BOLD response curve (maximum effect at approximately 6 s) was assumed. The part of the alpha regressor independent of the protocol condition, however, revealed significant positive thalamic and mesencephalic correlations with a mean time delay of approximately 2.5 s between EEG and BOLD signals. The inverse relationship between EEG alpha amplitude and BOLD signals in primary and secondary visual areas suggests that widespread thalamocortical synchronization is associated with decreased brain metabolism. While the temporal relationship of this association is consistent with metabolic changes occurring simultaneously with changes in the alpha rhythm, sites in the medial thalamus and in the anterior midbrain were found to correlate with short time lag. Assuming a canonical hemodynamic response function, this finding is indicative of activity preceding the actual EEG change by some seconds.

gamma-tocopherol traps mutagenic electrophiles such as NO(X) and complements alpha-tocopherol: physiological implications

Peroxynitrite, a powerful mutagenic oxidant and nitrating species, is formed by the near diffusion-limited reaction of .NO and O2.- during activation of phagocytes. Chronic inflammation induced by phagocytes is a major contributor to cancer and other degenerative diseases. We examined how gamma-tocopherol (gammaT), the principal form of vitamin E in the United States diet, and alpha-tocopherol (alphaT), the major form in supplements, protect against peroxynitrite-induced lipid oxidation. Lipid hydroperoxide formation in liposomes (but not isolated low-density lipoprotein) exposed to peroxynitrite or the .NO and O2.- generator SIN-1 (3-morpholinosydnonimine) was inhibited more effectively by gammaT than alphaT. More importantly, nitration of gammaT at the nucleophilic 5-position, which proceeded in both liposomes and human low density lipoprotein at yields of approximately 50% and approximately 75%, respectively, was not affected by the presence of alphaT. These results suggest that despite alphaT's action as an antioxidant gammaT is required to effectively remove the peroxynitrite-derived nitrating species. We postulate that gammaT acts in vivo as a trap for membrane-soluble electrophilic nitrogen oxides and other electrophilic mutagens, forming stable carbon-centered adducts through the nucleophilic 5-position, which is blocked in alphaT. Because large doses of dietary alphaT displace gammaT in plasma and other tissues, the current wisdom of vitamin E supplementation with primarily alphaT should be reconsidered.