A new approach for fat removal in a discontinuous autotransfusion device-concept and evaluation

BACKGROUND

Fat present during blood salvage in orthopaedic or cardiac surgery can pose a risk of fat embolism and should be eliminated before transfusion. Based on observations of central fat accumulation at the bottom of Latham bowls, a fat reduction program was developed using two volume displacements, where blood temporarily is removed and respun in the bowl to force the fat through the RBC sediment.

MATERIALS AND METHODS

Pooled ABO-matched RBC and FFP were adjusted to a haematocrit of 10%, and human fat tissue added to a concentration of 1·25 vol%. In six experiments, blood was processed with the new-generation cell salvage device CS Elite in a newly developed fat reduction program in bowls of three sizes. Volumetric quantification of fat was performed after centrifugation of blood samples in Pasteur pipettes. From volumes, haematocrits and the concentrations of fat, RBC recovery and fat elimination rates were calculated.

RESULTS

Fat removal rates of 93·2 ± 2·8, 97·0 ± 2·1 and 99·6 ± 0·3% were observed with a 70-ml, 125-ml and 225-ml bowl, respectively, and even higher rates when removal rates were calculated one cycle. At the same time, high RBC recovery and plasma elimination rates were maintained, not significantly different to the default program mode.

CONCLUSION

Modifications in process parameters and sequence led to a fat reduction program that significantly improves fat removal with the Cell Saver Elite from 77·4 ± 5·1% in the default mode to an average of 98·6 ± 1·1%, yielding results equivalent to the continuous cell salvage system (C.A.T.S).

Synthesis and characterisation of an unsymmetrical, ether-linked, fluorinated bimesogen exhibiting a new polymorphism containing the N(TB) or 'twist-bend' phase

In this article we report on the liquid crystal phases and properties of the bimesogen 4-((11-((4'-fluoro-[1,1'-biphenyl]-4-yl)oxy)undecyl)oxy)-2,3-difluoro-4'-(4-propylcyclohexyl)-1,1'-biphenyl. This material was shown to exhibit an Iso Liq-N-NTB-SmA phase sequence, thereby clearly indicating that the NTB phase possesses an ordering of the constituent molecules that is between that of a conventional nematic and the smectic A phase. This compound allows us to better understand the relationship between molecular structure and the NTB phase, and we conclude it is the gross topology that dictates the incidence of this fascinating phase and not molecular properties such as dipole moment and bend angle.

Recombinant human Monocyte/Neutrophil elastase inhibitor protects rat lungs against injury from cystic fibrosis airway secretions

Human monocyte/neutrophil elastase inhibitor (M/NEI) is a fast-acting stoichiometric inhibitor of neutrophil elastase (NE), cathepsin-G, and proteinase-3. Recombinant M/NEI (rM/NEI) was evaluated with a rat model of NE-induced lung damage. rM/NEI was found to protect against pulmonary injury caused by instilled human NE or by a preparation from airway secretions (sputum) of cystic fibrosis patients (CF sol). Human NE instilled into rat lungs produced dose-dependent hemorrhage and increased epithelial permeability, whereas NE incubated in vitro with rM/NEI did neither. Similarly, hemorrhage was induced by CF sol, but not by CF sol incubated in vitro with rM/NEI. To examine its distribution and survival time in airways, rM/NEI was labeled with the fluorochrome Texas Red (rM/NEI-TR) and instilled into rat lungs. Confocal microscopy showed that rM/NEI-TR could be detected on large airways (300 microm) at 5 min, 1 h, 4 h, and 24 h after instillation. Pretreating rats with rM/NEI was found to provide extended protection upon subsequent NE challenge, reducing hemorrhage by 98, 96, and 73%, respectively, at 1, 4, and 24 h after rM/NEI pretreatment. Pretreating rats with rM/NEI similarly conferred protection against subsequent exposure to CF sol, reducing hemorrhage by 95, 86, and 87%, respectively, at 1, 4, and 24 h after pretreatment. The findings that rM/NEI (1) mitigates protease-induced lung injury and (2) remains present and active in the lungs for 24 h after instillation strongly support its potential for treating patients with neutrophil protease-induced inflammatory lung damage, such as occurs in CF and other diseases.

Production of recombinant human monocyte/neutrophil elastase inhibitor (rM/NEI)

Recombinant human monocyte/neutrophil elastase inhibitor (rM/NEI) was expressed with a baculovirus expression system. The purified recombinant protein was shown to inhibit human neutrophil elastase by the formation of a stable equimolar complex, as had been shown for M/NEI isolated from monocyte-derived cell lines. rM/NEI was remarkably stable in aqueous buffers from pH 6 to pH 8, but not in buffers below pH 6. rM/NEI activity was stable when subjected to freeze-thaw cycles and low temperature storage in Tris or phosphate buffers. rM/NEI could also be lyophilized without significant loss of activity. A 1.6-g batch of greater than 95% purity in rM/NEI was obtained by anion exchange and size exclusion chromatography with yields of 7 to 8 mg per liter of cultured insect cells. Methods and protocols were chosen for compatibility with large-scale cGMP production and were suitable for biochemical characterization and preclinical evaluation of rM/NEI as a therapeutic agent for cystic fibrosis. The availability of large amounts of purified rM/NEI will facilitate clinical evaluation of rM/NEI for prevention of the elastase-mediated destruction of lung tissue associated with the morbidity and mortality of cystic fibrosis.

Expression and purification of enzymatically active recombinant granzyme B in a baculovirus system

Granzyme B (GranB), a serine protease stored in the granules of cytotoxic T lymphocytes and natural killer cells, can initiate target cell apoptosis. To produce large amounts of purified active enzyme, recombinant murine granzyme B (rGranB) was expressed from baculovirus in insect cells. The expressed rGranB is secreted into the culture medium and can be readily purified to homogeneity by one-step affinity chromatography to yield 1.5 mg enzyme per liter insect cell medium. RGranB is recognized by a GranB-specific anti-peptide antibody and is active against synthetic substrate Boc-Ala-Ala-Asp-SBzl with kinetic constant (kcat/Km 45,000 M-1s-1) comparable to purified human GranB, RGranB processes the caspase pro-CPP32 into its enzymatically active form and induces DNA fragmentation in isolated nuclei in the presence of cytosolic factors. The ability to express enzymatically active rGranB using the baculovirus system will help elucidate the role of this granzyme in the immune response.

Inhibition of germ tube development of Aspergillus fumigatus in cell-free transudate produced in subcutaneous chambers in rabbits

The interaction of Aspergillus fumigatus conidia with host factors produced in rabbits was studied by means of subcutaneous, perforated plastic chambers. Transudate fluid from spore-free chambers, sampled 30 days after implantation, supported germ tube development and rapid hyphal growth of A. fumigatus in an assay in vitro. Inoculation of spores into chambers implanted 30 days previously produced a rapid infiltration of leukocytes, predominately neutrophils, into the chamber fluid. Cell-free supernatants, prepared from transudates collected 5-6 days after inoculation, inhibited germ tube development in vitro. This inhibition was also demonstrated using lysates derived from 3.6 X 10(6) leukocytes obtained from chambers 5 days after inoculation with 1 X 10(7) spores. However, lysates derived from greater than 10(7) leukocytes obtained from pre-inoculated chambers as well as peritoneal exudate cells did not inhibit germ tube development in vitro. The inhibitory activity of cell free supernatants was not altered by heating at 56 degrees C for 30 min but was destroyed by pronase treatment as well as boiling. These results provide evidence for a host defense mechanism against rapid hyphal extension mediated by the extracellular release of inhibitory factors by leukocytes.

Hageman-factor-dependent fibrinolysis: generation of fibrinolytic activity by the interaction of human activated factor XI and plasminogen

Human coagulation factor XI has been purified, and upon activation with Hageman factor fragments, was found to convert the fibrinolytic proenzyme plasminogen to plasmin. This proactivator activity was shown to be functionally and antigenically distinct from prekallikrein. When the gamma-globulin fractions of plasma deficient in Hageman factor, prekallikrein and factor XI were isolated, factor-XI-deficient plasma possessed two-thirds of the plasminogen proactivator activity of the Hageman-factor-deficient plasma, while prekallikrein deficient plasma had only one-third of the plasminogen proactivator activity. Thus, the Hageman-factor-dependent plasminogen proactivator previously reported to be present in the gamma-globulin fraction of normal human plasma is a function of prekallikrein and factor XI, while the activity observed in prekallikrein-deficient plasma is attributable to factor XI. When compared utilizing digestion of iodinated fibrin, prekallikrein and factor XIa had similar potency per active site; they were, however, far less active than urokinase.

Characterization of ten species of mycobacteria by reaction-gas-liquid chromatography

The methanolic tetramethylammonium hydroxide whole-cell lysates of nine species of mycobacteria and the "rhodochrous complex" were examined by gas-liquid chromatography. The gas chromatographic patterns produced 10 characteristic chromatographic groups that corresponded to the 10 species studied. The gas chromatograms of Mycobacterium tuberculosis were very easily distinguished from the other mycobacterial strains by high levels of a component that eluted much later than the other components. The remaining nine species could be distinguished on the basis of characteristic components and by different amounts of components common to more than one species. This study demonstrated that direct gas-liquid chromatographic characterization of M. tuberculosis and other myobacterial species was not only feasible but practical in the clinical laboratory.

Inhibition of complement by mouse serum: selective inactivation of the fourth component of human complement

Bound human C4b on EAC4 is rapidly inactivated in the presence of murine serum reagents. The functional characteristics of this inactivation suggest that it is probably caused by factor(s) homologous to human C3bI-C4bI: inactivation is temperature-dependent and occurs without concomitant consumption of the inactivator(s); loss of hemolytic function is associated with the cleavage of the bound C4b into C4c, which is released, and C4d, which is retained on the cell membrane. Murine serum reagents inhibit bound human C4b far more efficiently than C3b and may therefore be employed to selectively inhibit C4b.

Identification of prekallikrein and high-molecular-weight kininogen as a complex in human plasma

Prekallikrein and high-molecular-weight kininogen were found associated in normal human plasma at a molecular weight of 285,000 as assessed by gel filtration on Sephadex G-200. The molecular weight of prekallikrein in plasma that is deficient in high-molecular-weight kininogen was 115,000. This prekallikrein could be isolated at a molecular weight of 285,000 after plasma deficient in high-molecular-weight kininogen was combined with plasma that is congenitally deficient in prekallikrein. Addition of purified 125I-labeled prekallikrein and high-molecular-weight kininogen to the respective deficient plasma yielded a shift in the molecular weight of prekallikrein, and complex formation could be demonstrated by incubating prekallikrein with high-molecular weight kininogen. This study demonstrates that prekallikrein and high-molecular-weight kininogen are physically associated in plasma as a noncovalently linked complex and may therefore be adsorbed together during surface activation of Hageman factor. The complex is disrupted when these proteins are isolated by ion exchange chromatography.

Human C3 and C5: subunit structure and modifications by trypsin and C42-C423

The subunit composition of human C3 and C5 was analyzed. Acrylamide gel electrophoresis of the fully reduced and dissociated proteins disclosed a similar structure, consisting of one alpha and beta subunit, linked together by one or more disulfide bonds. The approximate molecular weights for the alpha and beta subunits of C3 as well as C5 were 140,000 and 80,000 respectively. C42 caused cleavage solely of C3alpha, whereas trypsin affected both C3alpha as well as C3beta. A characteristic subunit modification by both enzmes indicated that C3alpha constitutes the source of C3a. C423 as well as trypsin exclusively affect C5alpha. C5a therefore appears to originate from the C5alpha subunit. The mode of primary cleavage by C423 and trypsin differs, giving rise to different forms of C5b. The questions is raised if multiple forms of C5a also exist. It appeared from our studies that certain forms of C5b may retain portions of the alpha subunit, which could potentially release some biologically active split products following secondary cleavage by the appropriate enzyme.

New gas chromatographic characterization procedure: preliminary studies on some Pseudomonas species

Strains of saccharolytic and nonsaccharolytic Pseudomonas species were examined by a new single-step gas chromatographic characterization procedure. Cells were digested in a methanolic solution of tetramethylammonium hydroxide pentahydrate, and the digestates were subjected to gas-liquid chromatographic analysis. The chromatograms were examined for similarities and differences in their overall patterns. A single component was defined for use as an internal qualitative and quantitative standardizing component in order to develop relative retention time-relative peak height profiles of each organism. Comparison of these profiles enabled the characterization of strains of Pseudomonas aeruginosa, P. putida, P. cepacia, P. pseudomallei, P. stutzeri, P. pseudoalcaligenes, P. alcaligenes, P. diminuta, P. denitrificans, and P. acidovorans. The P. maltophilia and P. putrefaciens digestates showed chromatograms which were superficially similar yet easily distinguished as belonging to different species. The chromatograms of these two organisms were very different from those of other pseudomonads.

Method for the preservation of diagnostic sera for field and laboratory work

Paper discs impregnated with antiserum, lyophilized, and stored at temperatures ranging from -21 to 33 C have yielded potent and specific reagents when rehydrated 370 days later. Applications are discussed.

Medical applications of dust-free rooms. 3. Use in an animal care laboratory

Bacterial air sampling in an animal care laboratory showed that dense aerosols are generated during cage changing and cage cleaning. Reyniers and Andersen sampling showed that the airborne bacteria numbered 50 to 200 colony-forming units (CFU)/ft(3) of air. Of the viable particles collected by Andersen samplers, 78.5% were larger than 5.5 mum. A low velocity laminar air flow system composed of high-efficiency particulate air (HEPA) filters and a ceiling distribution system maintained the number of airborne viable particles at low levels, generally less than 2 CFU/ft(3). Vertical air flow of 15 ft/min significantly reduced the rate of airborne infection by a strain of Proteus mirabilis. Other factors shown to influence airborne infection included type of cage utilized, the use of bedding, the distance between cages, and the number of animals per cage.