The liver-resident immune cell repertoire - A boon or a bane during machine perfusion?

The liver has been proposed as an important "immune organ" of the body, as it is critically involved in a variety of specific and unique immune tasks. It contains a huge resident immune cell repertoire, which determines the balance between tolerance and inflammation in the hepatic microenvironment. Liver-resident immune cells, populating the sinusoids and the space of Disse, include professional antigen-presenting cells, myeloid cells, as well as innate and adaptive lymphoid cell populations. Machine perfusion (MP) has emerged as an innovative technology to preserve organs ex vivo while testing for organ quality and function prior to transplantation. As for the liver, hypothermic and normothermic MP techniques have successfully been implemented in clinically routine, especially for the use of marginal donor livers. Although there is evidence that ischemia reperfusion injury-associated inflammation is reduced in machine-perfused livers, little is known whether MP impacts the quantity, activation state and function of the hepatic immune-cell repertoire, and how this affects the inflammatory milieu during MP. At this point, it remains even speculative if liver-resident immune cells primarily exert a pro-inflammatory and hence destructive effect on machine-perfused organs, or in part may be essential to induce liver regeneration and counteract liver damage. This review discusses the role of hepatic immune cell subtypes during inflammatory conditions and ischemia reperfusion injury in the context of liver transplantation. We further highlight the possible impact of MP on the modification of the immune cell repertoire and its potential for future applications and immune modulation of the liver.

The natural alpha angle of the femoral head-neck junction: a cross-sectional CT study in 1312 femurs.

Aims: Asphericity of the femoral head-neck junction is common in cam-type femoroacetabular impingement (FAI) and usually quantified using the alpha angle on radiographs or MRI. The aim of this study was to determine the natural alpha angle in a large cohort of patients by continuous circumferential analysis with CT. Methods: CT scans of 1312 femurs of 656 patients were analyzed in this cross-sectional study. There were 362 men and 294 women. Their mean age was 61.2 years (18 to 93). All scans had been performed for reasons other than hip disease. Digital circumferential analysis allowed continuous determination of the alpha angle around the entire head-neck junction. All statistical tests were conducted two-sided; a p-value < 0.05 was considered statistically significant. Results: The mean maximum alpha angle for the cohort was 59.0° (sd 9.4). The maximum was located anterosuperiorly at 01:36 on the clock face, with two additional maxima of asphericity at the posterior and inferior head-neck junction. The mean alpha angle was significantly larger in men (59.4°, sd 8.0) compared with women (53.5°, sd 7.4°; p = 0.0005), and in Caucasians (60.7°, sd 9.0°) compared with Africans (56.3°, sd 8.0; p = 0.007) and Asians (50.8°, sd 7.2; p = 0.0005). The alpha angle showed a weak positive correlation with age (p < 0.05). If measured at commonly used planes of the radially reconstructed CT or MRI, the alpha angle was largely underestimated; measurement at the 01:30 and 02:00 positions showed a mean underestimation of 4° and 6°, respectively. Conclusion: This study provides important data on the normal alpha angle dependent on age, gender, and ethnic origin. The normal alpha angle in men is > 55°, and this should be borne in mind when making a diagnosis of cam-type morphology. Cite this article: Bone Joint J 2018;100-B:570-8.

[Fluoroscopy-based 3D navigation of complex correction osteotomies at the proximal femur]. / Fluoroskopiebasierte 3D-Navigation komplexer Korrekturosteotomien des proximalen Femurs.

BACKGROUND: Despite great advances in hip alloarthroplasty there are still numerous indications for joint-saving procedures such as correction osteotomies. Often these procedures include complex 3D rearrangements of the proximal femur, which are for the surgeon technically very demanding. The project aim was to develop a precise intraoperative virtual 3D planning tool including a detailed biomechanical analysis and enable the surgeon to realize exactly this plan by using computer-assisted techniques. METHODS: Using only two different angled fluoro frames a simplified femoral model was inversely constructed. For navigation a passive optical system was used with a C-arm calibration kit and PC-based software. For in vitro evaluation complex osteotomies were performed on ten femora under simulated OR conditions. RESULTS: The mean difference between the planning and real surgical outcome for the wedge size was less then 2 degrees and for the femur head center position less then 4 mm. No implant penetrated the femur neck isthmus. CONCLUSION: Without changing the standard operative procedure the method can be of high clinical importance to improve planning accuracy and consecutive operative realization for precise fragment positioning and plate location without penetrating the isthmus of the femoral neck. And -- besides precision -- it can potentially help to reduce intraoperative complications such as implant penetration and minimize X-ray use.

Intraoperative, fluoroscopy-based planning for complex osteotomies of the proximal femur.

Intertrochanteric osteotomy of the proximal femur is a surgical technique that aims at changing the orientation of the proximal part of the femur in the hip joint by removing a bone wedge between the trochanters. Due to its six degrees of freedom, it presents a complex planning problem for the surgeon. In this paper, we propose an intraoperative planning system for proximal femur osteotomies. Based on two fluoroscopic images taken during the procedure, a primitive femur model is reconstructed, which then allows the user to interactively determine the osteotomy parameters and perform the intervention with the help of a navigation system. Besides the fluoroscopic images, no other imaging is needed. Compared to the traditional approach, this system allows the intervention to be performed with higher precision and less radiation exposure for both patient and surgeon, requiring only little time overhead. An in vitro study has demonstrated the high accuracy and ease of use of this system.

Multicentre evaluation of a non-wipe system for the rapid determination of total cholesterol in capillary blood, Accutrend Cholesterol on Accutrend GC.

Accutrend Cholesterol, a non-wipe test for the determination of total cholesterol in capillary blood, was evaluated at four clinical centres. Cholesterol determinations with the Accutrend system using capillary blood were compared with results obtained with the cholesterol oxidase/p-aminophenazone (CHOD-PAP) method using the respective capillary sera. Triacylglycerols, uric acid and haematocrit were determined to evaluate potential interference. Imprecision measurements were performed with venous blood. To examine the reproducibility of results from lot to lot, three different lots of test strips were included in these investigations. Results with Accutrend Cholesterol agree with those of the comparison method within systematic differences of +2.5% to -3.2%, depending on the lot. There was no interference by triacylglycerols up to 10.28 mmol/l (900 mg/dl), by uric acid 60 to 400 mumol/l (1 mg/dl to 7 mg/dl), or by haematocrits between 0.35 and 0.54. Impression data show coefficients of variation of generally less than 5%. Thus Accutrend Cholesterol proved to be a reliable system for the determination of total cholesterol.

[Enzyme immunoassay for the determination of albumin in urine]. / Enzymimmunoassay zur Bestimmung von Albumin im Urin.

Two modifications of a double antibody enzyme immunoassay for the determination of urinary albumin content are described. The method is simple, rapid and precise and can be carried out in test tubes and on microtiter plates as well. In 1:10 diluted urine samples albumin concentrations of 1.25 to 20 mg/l (corresponding to the normal range) can be determined. For a control sample with 0.3 mg/l albumin the intra- and interassay coefficients of variation were 4.9% (n = 11) and 10.4% (n = 21), respectively, on microtiter plates.

Evaluation of metabolic control in type 1 (insulin-dependent) diabetic patients by estimation of serum fructosamine.

The method of Johnson et al. (1982) for the estimation of non-enzymatically glycated serum proteins (fructosamine test) was critically evaluated and modified with respect to photometric readings, incubation conditions, and standardization of the procedure. With this modified method, serum fructosamine concentrations were estimated in type 1 (insulin-dependent) diabetic patients whose glycemic control ranged from strictly to poorly controlled and in normoglycemic healthy control subjects. The mean fructosamine concentrations were for the control group (n = 52) 2.17 mmol/l (range 1.73-2.61 mmol/l) and for the diabetic patients (n = 432) 2.87 +/- 0.60 mmol/l (range 2.27-3.25 mmol/l). There were significant differences in fructosamine concentrations among the diabetic patients, corresponding to the degree of metabolic control. Serum fructosamine levels were closely correlated to the HbA1 levels. Compared with HbA1, fructosamine reflects short-term metabolic changes and appears to be an useful index of short-term glycemia.

[The fructosamine test for the determination of nonenzymatic glycosylated serum proteins. A critical inspection of the method]. / Der Fructosamintest zur Bestimmung nichtenzymatisch glykosylierter Serumproteine. Eine methodenkritische Betrachtung.

A modification of the original method of R.A. Johnson et al. for nonenzymatically glycated serum proteins (fructosamine test) is described. Problems of performance and optimization of the method as well as of calibration and the influence of protein composition on the results are discussed. Measuring is manually performed after a 8 min preincubation interval over a 1 min's period using the spectrophotometer "Spekol 220". Interserial precision was 3.2%. First clinical results demonstrate the possibility to assess glycemic control in type 1 diabetic patients over a integrated time interval.

Importance of cardiovascular autonomic dysfunction in IDDM subjects with diabetic nephropathy.

Diabetic nephropathy (DNP) is associated with increased cardiovascular mortality. This may be contributed to by associated cardiovascular autonomic dysfunction (CAD). The aim of this study was to investigate the prevalence of CAD in patients with insulin-dependent diabetes mellitus (IDDM) at different stages of DNP. We studied patients with incipient DNP (group 1, n = 10), overt DNP (group 2, n = 20), renal insufficiency (group 3, n = 27), and end-stage renal failure (group 4, n = 12) and compared them with 30 IDDM patients without clinical signs of DNP (group 5) and with 17 nondiabetic controls (group 6). All groups were matched for age and diabetic groups were matched for duration of diabetes. Assessments of CAD included beat-to-beat variation during forced respiration, heart-rate response to standing, heart-rate response to Valsalva maneuver, basal heart rate, and blood pressure response to standing. Clinical evaluation included assessment of the history and an examination for peripheral polyneuropathy. We found mean impairment of heart-rate variation during respiration, in response to Valsalva maneuver, and in heart-rate response to standing in all diabetic groups compared with nondiabetic controls (P less than .01). Heart-rate responses differed significantly between patients with renal insufficiency (groups 3 and 4) and with other patient groups (group 5; P less than .01). CAD was shown to be more prevalent in patients with DNP, more so as DNP progresses. To some extent, it is already present in the early stages of DNP. CAD may be a contributory factor for increased cardiovascular mortality in patients with DNP.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of goldthioglucose on hormone secretion of pancreatic rat islets in vitro.

Goldthioglucose enhanced independently of glucose but related to dose the insulin secretion of pancreatic rat islets in vitro. The stimulatory action is additive to that of glucose, is not inhibited by mannoheptulose and not connected with an altered glucose-utilization. The gold thioglucose-induced insulin secretion is diminished in the presence of epinephrine and Mg++, respectively, and characterized by a uniphasic response peaking at 15 min. In the absence of glucose goldthioglucose did not modify the pancreatic glucagon secretion.

Radioligand assays-methods and applications. IV. Uniform regression of hyperbolic and linear radioimmunoassay calibration curves.

In order to handle all types of radioimmunoassay (RIA) calibration curves obtained in our laboratory in the same way, we tried to find a non-linear expression for their regression which allows calibration curves with different degrees of curvature to be fitted. Considering the two boundary cases of the incubation protocol we derived a hyperbolic inverse regression function: x = a1y + a0 + a-1y-1, where x is the total concentration of antigen, ai are constants, and y is the specifically bound radioactivity. An RIA evaluation procedure based on this function is described providing a fitted inverse RIA calibration curve and some statistical quality parameters. The latter are of an order which is normal for RIA systems. There is an excellent agreement between fitted and experimentally obtained calibration curves having a different degree of curvature.

Changes in the serine-specific transfer ribonucleic acid pattern of guinea pig epidermis after corticosteroid treatment.

The pattern of serine-specific tRNAs from guinea pig epidermis was determined and compared to that from liver by employing reversed phase chromatography on total tRNA preparations aminoacylated with 3H- or 14C-serine. Five tRNAserS (I-V) were found, two of which, tRNAserI and tRNAserV, appear to be "typical" for epidermis and in so far probably reflect in some way metabolic peculiarities of epidermal cell differentiation. This hypothesis was further corroborated by showing that the locally applied corticosteroid triamcinolon selectively increases tRNAserI and tRNAserV 2-3-fold. The implications of these findings were discussed in detail.

Apparent discrepancy between the insulin secretory responses in vivo and in vitro in carbohydrate-intolerant Sand rats.

A subpopulation (n = 27) of normoglycaemic Sand rats was characterized as carbohydrate-intolerant by intraperitoneal glucose loading. Five of these animals did not show any rise in peripheral insulin concentrations when injected with glucose. However, when isolated by collagenase digestion their islets still exhibited a significant enhancement of insulin secretion in response to glucose, glyceraldehyde, mannose and theophylline. The in vitro secretory responses were comparable to those of islets from carbohydrate-tolerant Sand rats. The results underline the importance of the natural environment for the B-cell response in vivo.