Quantitative deficiency of monocyte-specific esterase (MSE) mRNA in monocyte esterase deficiency (MED)

Efficiency of blood utilization in elective surgical patients

Background

Requesting blood prior to a surgical procedure for perioperative transfusion is a common practice in surgical patients. More unit of blood is requested than used by anticipating the patient will be transfused to provide a safety margin in an event of unexpected haemorrhage. Over requesting with minimal utilization results in significant wastage of blood, reagents and human resource. This study was conducted to assess blood utilization practice of the largest tertiary hospital in Ethiopia.

Methods

A cross-sectional prospective study method was used. Data was collected using a Proforma questionnaire by perusal of each individual patient’s records from December 1, 2017 to February 28, 2018.patient age, sex, department requesting the blood, level of operating surgeon, hemodynamic status, number of unit requested, number of unit crossed matched and number of unit transfused were collected. Efficiency of blood utilization was calculated with three indices: Crossmatch to transfusion ratio, transfusion probability, and transfusion index indices.

Results

Blood was requested for 406 patients and a total of 898 units were crossmatched for this patients. Overall Crossmatch to transfusion ration, transfusion probability and transfusion index were 7.6, 15.3% and 0.29 respectively. Results showed insignificant blood usage. Among different departments and units, better blood utilization was seen in neurosurgical unit with C/T ratio, TP and TI of 4.9, 24.4 and 0.6% respectively, while worst indices were from obstetrics unit with C/T ratio, TP and TI of 31.0, 6.5% and 0.06.

Conclusion

Using all the three parameters for evaluation of efficiency of blood utilization, the practice in our hospital shows ineffective blood utilization in elective surgical procedure. Blood requesting physician should order the minimum blood anticipated to be used as much as possible.

The interaction between hydrolytic and oxidative pathways in macrophage-mediated polyurethane degradation

Although relatively resistant to oxidation, polycarbonate-based polyurethanes (PCNUs) are degraded by monocyte-derived macrophages (MDM) by a co-mediated mechanism involving both hydrolytic and oxidative pathways. Since a previous study showed that PCNU pretreatment with H(2)O(2) modulated degradation by esterases, human MDM were used to further elucidate this dual pathway mechanism of degradation for (14)C-radiolabeled PCNUs (synthesized with 1,6-hexane diisocyanate:polycarbonatediol: butanediol with different stoichiometry (HDI431 and HDI321) or another diisocyanate 4,4'-methylene bisphenyl diisocyanate (MDI321)). Scanning electron microscopy of PCNU slips pretreated with 20% H(2)O(2) showed that HDI431 had visible holes with more radiolabel release than from the other PCNUs. When MDM were seeded on H(2)O(2)-treated PCNUs, degradation of HDI321 and MDI321, but not HDI431 was decreased. Esterase activity was inhibited in MDM on all surfaces except MDI321, whereas inhibition of acid phosphatase occurred on all surfaces. The material surface itself, induced H(2)O(2) release from live MDM, with more H(2)O(2) elicited by phorbol myristate acetate treated MDM when cultured on HDI431 but not the other materials. H(2)O(2) pretreatment affected cell function by chemically altering the material surface and MDM-mediated degradation, known to be dependent on surface chemistry. The findings highlight that both oxidative and hydrolytic mechanisms need to be understood in order to tailor material chemistry to produce desired cell responses for in vivo applications.

Is cell culture stressful? Effects of degradable and nondegradable culture surfaces on U937 cell function

In vitro cell culture has become one of the most widely used techniques in biological and health sciences research, with the most common culture supports being either tissue culture grade polystyrene (TCPS) or polydimethylsiloxane (PDMS). It has previously been shown that monocyte-derived macrophages (MDMs) respond to material surface chemistry, synthesizing and releasing degradative activities that could produce products, which alter the cell's response. In this study, functional parameters of differentiated U937 macrophage-like cells were compared when cultured on nondegradable standard control surfaces versus models of biomaterials (polycarbonate-based polyurethanes) used in the manufacture of medical devices previously shown to degrade and/or elicit pathways of inflammation. Although the influence of PDMS and TCPS on cell function is often underappreciated by investigators, both surfaces elicited enzyme markers of inflammation. Cells on TCPS had the highest intracellular and released esterase activities and protein levels. Cells on PDMS had the most released acid phosphatase activity and protein (P<0.001), as well as de novo 57− and 59− kDa released proteins. The criteria for defining an activated cell phenotype become critically important when materials such as PDMS and TCPS are used as standard control surfaces whether in experiments for research in elucidating metabolic pathways or in screening drugs and materials for therapeutic uses.

The functional response of U937 macrophage-like cells is modulated by extracellular matrix proteins and mechanical strain

Extracellular matrix proteins (ECMs) play a significant role in the transfer of mechanical strain to monocyte-derived macrophages (MDMs) affecting morphological changes in a foreign body reaction. This study investigated how the functional responses of U937 macrophage-like cells differed when subjected to 2 dynamic strain types (nonuniform biaxial or uniform uniaxial strain) while cultured on siloxane membranes coated with either collagen type I or RGD peptide repeats (ProNectin®). Biaxial strain caused an increase in intracellular esterase and acid phosphatase (AP) activities, as well as monocyte-specific esterase (MSE) protein levels in cells that were seeded on either uncoated surfaces (shown previously) or collagen, but not ProNectin®. Released AP activity, but not released esterase activity, was increased on all surfaces. Biaxial strain increased IL-6, but not IL-8 on all surfaces. When cells were subjected to uniaxial strain, intracellular esterase increased on coated surfaces only, whereas intracellular AP activity was unaffected. Both esterase and AP released activities increased on all surfaces. Uniaxial strain increased the release of IL-6 on all surfaces, but IL-8 on coated surfaces only. This study demonstrated for the first time that ECM proteins could specifically modulate cellular responses to different types of strain. Using this approach with an in vitro cell system may help to unravel the complex function of MDMs in the foreign-body reaction.