Transcatheter aortic valve implantation (TAVI) for treatment of aortic valve stenosis: an evidence-based Analysis (part B)

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical aortic valve replacement (sAVR) for patients at high risk for surgery.

OBJECTIVE

To evaluate the safety, effectiveness, and cost-effectiveness of TAVI for treatment of aortic valve stenosis in symptomatic older adults.

REVIEW METHODS

A literature search was performed on September 6, 2011, for studies published from January 1, 2007, to September 6, 2011. A combined decision tree and Markov model was developed to compare costs, life years, and quality-adjusted life-years (QALYs) of all treatment options in their respective patient populations over a 20-year time horizon.

RESULTS

Two studies from the PARTNER trial were identified. The first study compared TAVI to sAVR in patients who were candidates for sAVR. The second study compared TAVI to standard treatment in patients who were not eligible for sAVR. The first study showed that TAVI and sAVR had similar mortality rates at 1 year. The second study showed a significant improvement in patient survival in those undergoing TAVI. However, in both studies, the TAVI group had significantly higher rates of stroke/transient ischemic attack, and major vascular complications. Rates of major bleeding were significantly higher in sAVR group in the first study and significantly higher in TAVI group in the second study. The base-case cost-effectiveness of TAVI was $48,912 per QALY, but the incremental cost-effectiveness ratio ranged from $36,000 to $291,000 per QALY depending on the assumptions made in the longer-term prediction portion of the model (i.e., beyond the follow-up period of the PARTNER trial).

CONCLUSIONS

TAVI improves survival in patients who cannot undergo surgery. For those who are candidates for surgery, TAVI has a mortality rate similar to sAVR, but it is associated with significant adverse effects. TAVI may be cost-effective for patients who cannot undergo surgery, but is not cost-effective for patients who can.

A novel monoclonal antibody against human CD80 and its immune protection in a mouse lupus-like disease

Blockade of the interactions between CD28/CTLA-4 and their ligands, CD80 (B7, B7.1)/CD86 (B70, B7.2), is an attractive means to induce antigen-specific peripheral tolerance in autoimmune disease and organ transplantation. In this study, we generated and characterized a monoclonal antibody (Clone 4E5) against human CD80. 4E5 could recognize both human and mouse CD80 and suppress mixed lymphocyte reaction in vitro. To investigate their potency for clinical use, we further administrated 4E5 to a mouse lupus-like disease model (C57BL/J6) induced by Pristane. 4E5 could inhibit the immune response and attenuate the severity of lupus-like disease. The data showed 4E5 function and suggested that blockade of CD80/CD28 co-stimulatory signal pathway with 4E5 is a promising strategy to decelerate the progression of lupus-like disease and other autoimmune diseases.

Joint analysis of the Cs2 a3Σu+ and 1g (3(3)Π1g) states

Sets of experimental data on the Cs(2) a(3)Σ(u)(+) and 1(g) (3(3)Π(1g)) states, including the bound-bound and bound-free fluorescence spectra, are analyzed simultaneously to produce the potential energy curves of both states in the form of the Morse long range multiparameter function. The attractive branch of the a(3)Σ(u)(+) state potential is improved relative to the one reported in our earlier work [F. Xie, V. B. Sovkov, A. M. Lyyra, D. Li, S. Ingram, J. Bai, V. S. Ivanov, S. Magnier, and L. Li, J. Chem. Phys. 130, 051102 (2009)], in which the data on this state alone were analyzed. Besides, the new potential of this state also includes the repulsive branch in the range spanned by the bound-free fluorescence spectra. We have not found experimental evidence of the double minimum character of the 3(3)Π(1g) state potential, predicted by ab initio calculations, at least up to v = 8. This fact testifies that the upper state observed is better described by the Hund coupling case (c), in which the case (a) electronic basis states are intermixed by the strong spin-orbit interaction.

An in vitro study of two GAG-like marine polysaccharides incorporated into injectable hydrogels for bone and cartilage tissue engineering

Natural polysaccharides are attractive compounds with which to build scaffolds for bone and cartilage tissue engineering. Here we tested two non-standard ones, HE800 and GY785, for the two-dimensional (2-D) and three-dimensional (3-D) culture of osteoblasts (MC3T3-E1) and chondrocytes (C28/I2). These two glycosaminoglycan-like marine exopolysaccharides were incorporated into an injectable silylated hydroxypropylmethylcellulose-based hydrogel (Si-HPMC) that has already shown its suitability for bone and cartilage tissue engineering. Results showed that, similarly to hyaluronic acid (HA) (the control), HE800 and GY785 significantly improved the mechanical properties of the Si-HPMC hydrogel and induced the attachment of MC3T3-E1 and C28/I2 cells when these were cultured on top of the scaffolds. Si-HPMC hydrogel containing 0.67% HE800 exhibited the highest compressive modulus (11kPa) and allowed the best cell dispersion, especially of MC3T3-E1 cells. However, these cells did not survive when cultured in 3-D within hydrogels containing HE800, in contrast to C28/I2 cells. The latter proliferated in the microenvironment or concentrically depending on the nature of the hydrogel. Among all the constructs tested the Si-HPMC hydrogels containing 0.34% HE800 or 0.67% GY785 or 0.67% HA presented the most interesting features for cartilage tissue engineering applications, since they offered the highest compressive modulus (9.5-11kPa) while supporting the proliferation of chondrocytes.

Genetic deletion of Nogo/Rtn4 ameliorates behavioral and neuropathological outcomes in amyloid precursor protein transgenic mice

The cognitive impairment in Alzheimer's disease (AD) is associated with synaptic loss, neuritic sprouting and altered neuroplasticity. Compensatory neuritic sprouting might be beneficial, while aberrant sprouting could contribute to the neurodegenerative process. Nogo (or Rtn4) is a major myelin-derived inhibitor of axonal sprouting in adult CNS. Recent evidence has implicated both the Reticulon family of proteins and a receptor for Nogo, NgR, in reducing amyloid-beta production, a key step in AD pathogenesis. To test the hypothesis that Nogo, as an inhibitor of axonal sprouting, modulates disease progression in a mouse model of AD, we introduced an APP transgene (a human APP minigene carrying the Swedish and Indiana mutations under the platelet-derived growth factor subunit B (PDGFB) promoter) into a Nogo null background and characterized the behavioral and neuropathological consequences. We found that deleting Nogo ameliorates learning and memory deficits of APP transgenic mice in the Morris water maze at an early/intermediate stage of the disease. Furthermore, deleting Nogo restored the expression levels of markers for synapto-dendritic complexity and axonal sprouting including synaptophysin, MAP2, GAP43 and neurofilament that are otherwise reduced in APP transgenic mice. Other aspects of disease progression including neuronal loss, astrogliosis, microgliosis and, importantly, Abeta levels and amyloid deposits were not significantly altered by Nogo deletion. These data support the hypothesis that Nogo-mediated inhibition of neuritic sprouting contributes to the disease progression in an APP transgenic model of AD in a way that is mechanistically distinct from what has been proposed for Rtn3 or NgR.

Secretory expression of insulin precursor in pichia pastoris and simple procedure for producing recombinant human insulin

In this work, Pichia pastoris was applied to produce human insulin by a simple procedure. The synthesized insulin precursor (ILP) gene was inserted into pPIC9K to obtain secretary expression plasmid pPIC9K/ILP. Pichia pastoris GS115 was transformed by pPIC9K/ILP and the high expresser was screened. In a 16 L fermentor, the insulin precursor production was 3.6 g/L. Insulin precursor, purified by one-step chromatography, was converted into human insulin by transpeptidation. The yield of the processing procedure from insulin precursor to insulin reached up to 70%. In vivo assay showed that the biological activity of the produced recombinant human insulin was 28.8 U/mg.

Efficacy of nisin in treatment of clinical mastitis in lactating dairy cows

Nisin is an antimicrobial polypeptide produced by Lactococcus lactis and is believed nontoxic to humans. The objective of this study was to evaluate a nisin-based formulation for the treatment of bovine clinical mastitis in lactating dairy cattle. A total of 92 cows with 107 clinically mastitic quarters were randomly assigned to nisin- (48 cows with 51 quarters) and gentamicin (GM)-treated (44 cows with 56 quarters) groups. In the nisin-treated group, cows received an intramammary infusion of nisin at a dose of 2,500,000 IU; in the GM-treated group, intramammary infusion of GM was administered at a dose of 0.8 g. Results indicated that nisin offered a clinical cure rate similar to GM (90.2 vs. 91.1%) and no difference in bacteriological cure rate than GM-treated group (60.8 vs. 44.6%, respectively). Proportion of the quarters with milk somatic cell counts <500,000 cells/mL was not different in the nisin-treated group (50.0 and 47.8%) compared with the GM-treated group (33.3 and 37.3%) 1 and 2 wk after treatment. Of 17 Staphylococcus aureus isolates, 82.5% were resistant to penicillin, and 35.3% to GM, but none of them to nisin. Nisin therapy eliminated 54.5% (6 of 11) of S. aureus IMI, whereas GM eliminated 33.3% (2 of 6). Nisin in milk (4.5 +/- 0.8 IU/mL) was detected only at 12 h following intramammary infusion, which was much lower than the upper limit (500 mg/mL) allowed as preservative in milk by the China authority. Because of its efficacy in the treatment of bovine clinical mastitis, especially resistant Staph. aureus-caused IMI, as well as its safety in humans, nisin deserves further study to clarify its effects on mastitis caused by different mastitis pathogens on a larger scale.

Compound heterozygosity for two novel mutations (1203insG/Y1456X) in the von Willebrand factor gene causing type 3 von Willebrand disease

A 23-year-old Chinese woman with severe von Willebrand factor (VWF) deficiency and her parents were investigated by PCR/direct sequencing of the VWF gene. The patient was found to be compound heterozygous for two novel null mutations. The first was a microinsertion in exon 8 (1203insG) that introduced a frameshift at codon 298 leading to premature translational termination at codon 302. The second was a C to A transversion in exon 28 which resulted in the replacement of tyrosine 562 by a stop codon (Y1456X). The failure to amplify VWF cDNA from the patient by semi-nested PCR is consistent with the induction of nonsense-mediated mRNA decay.

Cross-cultural adaptation and validation of Singapore English and Chinese Versions of the Oxford Knee Score (OKS) in knee osteoarthritis patients undergoing total knee replacement

OBJECTIVE

To cross-culturally adapt and validate Singapore English and Chinese versions of the Oxford Knee Score (OKS) in patients with knee osteoarthritis (OA) undergoing total knee replacement (TKR) surgery.

METHODS

Singapore English and Chinese OKS versions were cross-culturally adapted from the source English version following standard guidelines (including cognitive debriefing), and validated by interviewing patients in English or Chinese using an identical, pretested questionnaire containing the OKS, Short Form 36, and EQ-5D. Reliability was assessed using Cronbach's alpha, dimensionality using principal component factor analysis and item-total correlations, convergent and divergent construct validity by assessing six and three a priori hypotheses, respectively.

RESULTS

The Singapore English and Chinese OKS were well accepted by patients in pilot testing. When administered to a consecutive sample of 127 English and 131 Chinese-speaking Singaporeans with knee OA (mean age 66 years, 83% female, mean duration of OA 6 years, Chinese:Malay:Indian:Others=78:7.9:11:3.1% for English version), Cronbach's alpha exceeded 0.8 and factor analysis yielded three factors for both versions. Hypothesized item-total correlations (Spearman's rho > or = 0.4) were observed for all items except limping, kneeling, and night knee pain in both versions. Convergent construct validity was supported by the presence of hypothesized moderate/strong correlations (rho=0.37-0.73) for six and five a priori hypotheses in English and Chinese versions, respectively. Divergent construct validity was supported by the presence of weak correlations (rho=0.09-0.30) for all three a priori hypotheses in both versions.

CONCLUSION

Singapore English and Chinese OKS demonstrated good patient acceptability and psychometric properties (including construct validity) among multiethnic Asian patients with knee OA undergoing TKR.

4IgB7-H3 is the major isoform expressed on immunocytes as well as malignant cells

Human B7-H3, a novel member of B7 family, has two isoforms (2IgB7-H3 and 4IgB7-H3). As costimulatory functions of both isoforms are not clarified, there has been much discussion on their expression patterns, T-cell responses, etc. This study generated two specific mouse anti-human 2IgB7-H3 monoclonal antibodies (mAbs) (7D7 and 10F1), whose specificities are quite different from those of the available B7-H3 mAb (21D4) by competition assay. The use of antibodies indicated that B7-H3 was found to have different expression patterns on monocyte-derived dendritic cells, that is the isoform 2IgB7-H3 is tended to express on immature dendritic cells (iDCs), whereas 4IgB7-H3 could be detected in the whole process of maturation of dendritic cells. The isoform 4IgB7-H3 was shown in the immunohistochemistry assay to be more widely expressed than 2IgB7-H3 in human benign and malignant hepatic tissues. Furthermore, flow cytometry and reverse transcription-polymerase chain reaction indicated that 4IgB7-H3 rather than 2IgB7-H3 was the major isoform on many human tumor cell lines. In addition, both 2IgB7-H3- and 4IgB7-H3-transfected cells could promote T-cell proliferation, which could be blocked by 7D7 mAb. These two novel antibodies may shed light on the function of the two B7-H3 isoforms.