Fatal Adverse Event with Dabigatran in Elderly Patient with Reduced Kidney Function

An elderly man with decreased kidney function was admitted to hospital with gastrointestinal bleeding. After remaining stable for 2 days in hospital, he became haemodynamically unstable and an adverse effect of dabigatran was suspected, but efforts to treat the patient failed and the following morning he passed away. In conjunction with the autopsy, blood samples from his hospital stay were analysed for dabigatran, revealing the highest concentration (6400 ng/mL) apparently reported to date. Supra‐therapeutic dosing was, however, never suspected. Dabigatran is largely excreted through the kidneys. A possible cause of the high dabigatran concentrations could be a rapid decrease in kidney function that seemingly occurred over a period of 2 months, sometime between his initiation of treatment (eGFR 51–55 mL/min/1.73 m²) and subsequent hospital admission (eGFR 31 mL/min/1.73 m²). The increasing dabigatran concentrations in the patient was, however, not apparent to the prescribing doctor, as therapeutic drug monitoring of dabigatran is not recommended in current guidelines and no such analyses were performed. There may be a need to evaluate blood concentrations of dabigatran, in the light of the reported differences in interindividual concentrations, along with the increased risks of thromboembolic events with lower concentrations and major bleeding events with higher concentrations. Functional assays to assess concentrations of dabigatran in blood have been developed and are available in some hospitals to be used in suspected overdoses or before emergency surgeries. Methods to determine concentrations of dabigatran specifically have also been developed and can additionally be used for therapeutic drug monitoring in an outpatient setting, especially in high‐risk individuals.     

Adverse Tumor Biology Associated with Mesenterico-Portal Vein Resection Influences Survival in Patients with Pancreatic Ductal Adenocarcinoma

Background

Although pancreatoduodenectomy (PD) with mesenterico-portal vein resection (VR) can be performed safely in patients with resectable pancreatic ductal adenocarcinoma (PDAC), the impact of this approach on long-term survival is controversial.

Patients and Methods

Analyses of a prospectively collected database revealed 122 consecutive patients with PDAC who underwent PD with (PD+VR) or without (PD?VR) VR between January 2004 and May 2012. Clinical data, operative results, and survival outcomes were analysed.

Results

Sixty-four (53 %) patients underwent PD+VR. The majority (84 %) of the venous reconstructions were performed with a primary end-to-end anastomosis. Demographic and postoperative outcomes were similar between the two groups. American Society of Anesthesiologists (ASA) score, duration of operation, intraoperative blood loss, and blood transfusion requirement were significantly greater in the PD+VR group compared with the PD?VR group. Furthermore, the tumor size was larger, and the rates of periuncinate neural invasion and positive resection margin were higher in the PD+VR group compared with the PD?VR group. Histological venous involvement occurred in 47 of 62 (76 %) patients in the PD+VR group. At a median follow-up of 29 months, the median overall survival (OS) was 18 months for the PD+VR group, and 31 months for the PD?VR group (p = 0.016). ASA score, lymph node metastasis, neurovascular invasion, and tumor differentiation were predictive of survival. The need for VR in itself was not prognostic of survival.

Conclusions

PD with VR has similar morbidity but worse OS compared with a PD?VR. Although VR is not predictive of survival, tumors requiring a PD+VR have more adverse biological features.     

Three-dimensional echocardiography of mitral Barlow's disease with infective endocarditis: Perforations or cleft-like indentations?

Barlow's disease is a complicated form of degenerative mitral valve (MV) disease. Infective endocarditis (IE) often occurs on the basis of primary heart diseases and may be combined with valve perforations. Cleft-like indentations (CLIs) were suggested by Ring et al. in 2013. They are located at the inter-scallop position and involve at least one-half of the valve. Herein, we report a case of Barlow's disease combined with IE and CLIs, which was confirmed intra-operatively and by histopathological examination. The CLIs were misdiagnosed by two-dimensional transthoracic echocardiography as perforations, but rightly interpreted by preoperative three-dimensional echocardiography. The possibility of CLIs should be considered in the evaluation of mitral regurgitation caused by myxomatous MV diseases.     

Interleukin-4 and interleukin-5 map to human chromosome 5 in a region encoding growth factors and receptors and are deleted in myeloid leukemias with a del(5q)

Interleukin-4 (IL-4) is a potent mediator of growth and differentiation of cells of several hematopoietic lineages. Interleukin-5 (IL-5) is a lineage-specific hematopoietic growth factor that stimulates the production of eosinophils and eosinophil colonies from normal human bone marrow cells. By using somatic cell hybrids and in situ chromosomal hybridization, we localized the IL-4 and IL-5 genes to human chromosome 5 at bands q23-31, a chromosomal region that is frequently deleted [del(5q)] in patients with myeloid disorders. By in situ hybridization, the IL-4 and IL-5 genes were found to be deleted in the 5q- chromosome of four patients with refractory anemia (RA) or therapy-related acute nonlymphocytic leukemia (t-ANLL), who had a del(5q). Thus a small segment of chromosome 5 contains IL-4, IL-5, IL- 3, and GM-CSF as well as other genes such as CD14 and EGR1. Our findings that each of these genes was deleted in the 5q- chromosome suggest that loss of function of one or more of these genes may play an important role in the pathogenesis of hematologic disorders associated with a del(5q).     

Fluorescence in situ hybridization mapping of translocations and deletions involving the short arm of human chromosome 12 in malignant hematologic diseases

Translocations and deletions of the short arm of chromosome 12 [t(12p) and del(12p)] are common recurring abnormalities in a broad spectrum of hematologic malignant diseases. We studied 20 patients and one cell line whose cells contained 12p13 translocations and/or 12p deletions using fluorescence in situ hybridization (FISH) with phage, plasmid, and cosmid probes that we previously mapped and ordered on 12p12-13. FISH analysis showed that the 12p13 translocation breakpoints were clustered between two cosmids, D12S133 and D12S142, in 11 of 12 patients and in one cell line. FISH analysis of 11 patients with deletions demonstrated that the deletions were interstitial rather than terminal and that the distal part of 12p12, including the GDI-D4 gene and D12S54 marker, was deleted in all 11 patients. Moreover, FISH analysis showed that cells from 3 of these patients contained both a del(12p) and a 12p13 translocation and that the affected regions of these rearrangements appeared to overlap. We identified three yeast artificial chromosome (YAC) clones that span all the 12p13 translocation breakpoints mapped between D12S133 and D12S142. They have inserts of human DNA between 1.39 and 1.67 Mb. Because the region between D12S133 and D12S142 also represents the telomeric border of the smallest commonly deleted region of 12p, we also studied patients with a del(12p) using these YACs. The smallest YAC, 964c10, was deleted in 8 of 9 patients studied. In the other patient, the YAC labeled the del(12p) chromosome more weakly than the normal chromosome 12, suggesting that a part of the YAC was deleted. Thus, most 12p13 translocation breakpoints were clustered within the sequences contained in the 1.39 Mb YAC and this YAC appears to include the telomeric border of the smallest commonly deleted region. Whether the same gene is involved in both the translocations and deletions is presently unknown.     

An inhibitory monoclonal antibody to factor X that blocks prothrombin activation but not prothrombinase enzyme assembly

A monoclonal antibody (designated alpha BFX-2b) prepared against bovine factor X inhibited factor X activity in human, bovine, porcine, rabbit, and canine plasma. In assays using purified prothrombinase components, factor Xa, factor Va, phospholipid vesicles, and calcium ion with the fluorescent active site thrombin inhibitor dansylarginyl-N-(3-ethyl-1,5- pentanediyl)amide, the antibody inhibited the conversion of prothrombin to thrombin. Antibody alpha BFX-2b also blocked prothrombinase cleavage of the macromolecular substrates prethrombin 1 and prethrombin 2 but did not inhibit factor Xa hydrolysis of the synthetic substrate benzoyl- Ile-Glu-Gly-Arg-p-nitroanilide. The antibody also prevented the inactivation of factor Xa by antithrombin III but did not prevent the inactivation by soybean trypsin inhibitor. Antibody alpha BFX-2b bound factor Xa with a stoichiometry of 1:1 and an apparent dissociation constant of 9.0 x 10(-11) mol/L as estimated from its inhibition of prothrombinase activity. Antibody alpha BFX-2b did not prevent binding of factor Xa to factor Va-phospholipid as measured by using fluorescence polarization or high-pressure liquid gel chromatography with the fluorescent Factor Xa analogue dansyl-glutamyl-glycyl-arginyl- Xa. Immunoblotting of factor X following electrophoresis on sodium dodecyl sulphate-polyacrylamide gels and transfer to nitrocellulose indicated that the antigenic determinant recognized by antibody alpha BFX-2b was found on the heavy chain of factors X and Xa. From these observations it can be concluded that antibody alpha BFX-2b recognizes a highly conserved epitope on the factor X heavy chain that is remote from the topographic sites required for prothrombinase complex assembly and substrate hydrolysis but may be located at or near a portion of the macromolecular substrate binding site.