Rapamycin and CTLA4Ig synergize to induce stable mixed chimerism without the need for CD40 blockade

The mixed chimerism approach achieves donor-specific tolerance in organ transplantation, but clinical use is inhibited by the toxicities of current bone marrow (BM) transplantation (BMT) protocols. Blocking the CD40:CD154 pathway with anti-CD154 monoclonal antibodies (mAbs) is exceptionally potent in inducing mixed chimerism, but these mAbs are clinically not available. Defining the roles of donor and recipient CD40 in a murine allogeneic BMT model, we show that CD4 or CD8 activation through an intact direct or CD4 T cell activation through the indirect pathway is sufficient to trigger BM rejection despite CTLA4Ig treatment. In the absence of CD4 T cells, CD8 T cell activation via the direct pathway, in contrast, leads to a state of split tolerance. Interruption of the CD40 signals in both the direct and indirect pathway of allorecognition or lack of recipient CD154 is required for the induction of chimerism and tolerance. We developed a novel BMT protocol that induces mixed chimerism and donor-specific tolerance to fully mismatched cardiac allografts relying on CD28 costimulation blockade and mTOR inhibition without targeting the CD40 pathway. Notably, MHC-mismatched/minor antigen-matched skin grafts survive indefinitely whereas fully mismatched grafts are rejected, suggesting that non-MHC antigens cause graft rejection and split tolerance.

An acetate-buffered balanced crystalloid versus 0.9% saline in patients with end-stage renal disease undergoing cadaveric renal transplantation: a prospective randomized controlled trial

BACKGROUND

Recent studies have shown a decline in glomerular filtration rate and increased renal vasoconstriction after administration of normal saline when compared with IV solutions with less chloride. In this study, we investigated the impact of normal saline versus a chloride-reduced, acetate-buffered crystalloid on the incidence of hyperkalemia during cadaveric renal transplantation. The incidence of metabolic acidosis and kidney function were secondary aims.

METHODS

In this prospective randomized controlled trial, 150 patients received normal saline or an acetate-buffered balanced crystalloid during and after cadaveric renal transplantation. Venous blood gases were obtained at the start of anesthesia and every 30 minutes until discharge from the postoperative surveillance unit. Serum creatinine and 24-hour urine output were obtained on postoperative days 1, 3, and 7.

RESULTS

Patients received a similar amount of fluid (median: 2625mL [interquartile range: 2000 to 3100] vs 2500 mL [2000 to 3050], P = 0.83). Hyperkalemia, defined as serum potassium >5.9 mmol/L, occurred in 13 patients (17%) in the saline and 15 (21%) in the balanced group (P = 0.56; difference between proportions -0.037 [-16.5% to 8.9%]). Minimum base excess was lower in the saline group compared with the balanced regimen (-4.5 mmol/L [-6 to -2.4] vs -2.6 mmol/L [-4 to -1], P < 0.001) and maximum chloride was significantly higher in the saline group (109 mmol/L [107 to 111] vs 107 mmol/L [105 to 109], P < 0.001). No difference in creatinine or urine output was seen postoperatively. Significantly more patients needed catecholamines in the saline group (30% vs 15%, P = 0.03).

CONCLUSIONS

The incidence of hyperkalemia differed by less than 17% between groups. Use of balanced crystalloid resulted in less hyperchloremia and metabolic acidosis. Significantly more patients in the saline group required administration of catecholamines for circulatory support.

Long-term outcome of belatacept therapy in de novo kidney transplant recipients - a case-match analysis

While belatacept has shown favorable short- and midterm results in kidney transplant recipients, only projections exist regarding its potential impact on long-term outcome. Therefore, we performed a retrospective case-match analysis of the 14 belatacept patients originally enrolled in the phase II multicenter trial at our center. Fifty six cyclosporine (CyA)-treated patients were matched according to age at transplantation, first/retransplant, and donor type. Ten years after kidney transplantation, kidney function remained superior in belatacept-treated patients compared with the CyA control group. Moreover, none of the belatacept-treated patients had donor-specific antibodies ≥10 years post-transplantation compared with 38.5% of tested CyA-treated subject (0/10 vs. 5/13; P = 0.045). Notably, however, patient and graft survival was virtually identical in both groups (71.4% vs. 71.3%; P = 0.976). In the present single-center study population, patients treated with belatacept demonstrated a patient and graft survival at 10 years post-transplant which was comparable to that of similarly selected CNI-treated patients. Larger studies with sufficient statistical power are necessary to definitively determine long-term graft survival with belatacept.

Surgical resection of metastases to the adrenal gland: a single center experience

BACKGROUND

Only limited data exist on the treatment and outcome of adrenal metastases that derive from different primary tumor entities. Due to the lack of evidence, it is difficult to determine the indication for surgical resection.

METHODS

We assessed the outcome of 45 patients (28 men, 17 women) with adrenal metastases who underwent surgery (1990-2014). The median age at the time of adrenal surgery was 62 years (range 44-77 years). We were able to evaluate follow-up data of 41 patients.

RESULTS

Primary tumor types were liver n = 12 (hepatocellular carcinoma n = 9, cholangiocellular carcinoma n = 2, sarcoma n = 1), upper GI tract n = 5 (esophagus n = 2, stomach n = 3), lung n = 9, kidney n = 6, neuroendocrine tumors n = 3, colon n = 2, ovarial n = 2, melanoma n = 2, others n = 4. The overall median survival time was 14 months (95 % CI 8.375-19.625). The survival rates at 1, 2, 5, and 10 years were 60, 31, 21, and 11 %, respectively. There were statistically significant differences in the survival time according to the resection status (R0 vs. R1/R2) (p < 0.001) and the type of the primary tumor (p = 0.009), while the metachronous or synchronous occurrence of adrenal metastases did not affect the prognosis.

CONCLUSIONS

Resection of adrenal metastases can improve the survival if patients are carefully selected, the tumor is completely resected, and the intervention is integrated into a multidisciplinary oncologic treatment strategy.

Belatacept treatment for two yr after liver transplantation is not associated with operational tolerance

Belatacept was recently evaluated in liver transplantation (LT) in a phase II multicenter trial, which was terminated prematurely. Patients were more than two yr post-LT at the time. As high rates of spontaneous tolerance after LT have been reported and as belatacept has marked immunomodulatory effects, we decided to maintain the belatacept patients enrolled at our center (n = 4) on MMF monotherapy. All belatacept patients on MMF monotherapy developed graft dysfunction consistent with acute rejection after a mean period of 10.3 (7-14) wk. Patients were therefore switched to triple therapy with CNI, MMF, and corticosteroids. Graft dysfunction resolved within 1-3 wk after switch. At the time of belatacept discontinuation, mean eGFR was 105.1 mL/min/1.73 m² (92.1-118.9) in belatacept patients compared to 58 mL/min/1.73 m² (36.1-98.2) in controls (p = 0.022). One yr after the switch to CNI therapy, eGFR had declined by 27.4 mL (19.2-39.3; p = 0.008). Thus, LT patients treated with belatacept show superior kidney function that declines upon institution of CNIs. MMF monotherapy following withdrawal of belatacept is associated with a high incidence of graft dysfunction. Belatacept has no obvious immunomodulatory effects in LT recipients that would be sufficient to allow drug withdrawal with a high rate of success.

Phytate in pig and poultry nutrition

Phosphorus (P) is primarily stored in the form of phytates in plant seeds, thus being poorly available for monogastric livestock, such as pigs and poultry. As phytate is a polyanionic molecule, it has the capacity to chelate positively charged cations, especially calcium, iron and zinc. Furthermore, it probably compromises the utilization of other dietary nutrients, including protein, starch and lipids. Reduced efficiency of utilization implies both higher levels of supplementation and increased discharge of the undigested nutrients to the environment. The enzyme phytase catalyses the stepwise hydrolysis of phytate. In respect to livestock nutrition, there are four possible sources of this enzyme available for the animals: endogenous mucosal phytase, gut microfloral phytase, plant phytase and exogenous microbial phytase. As the endogenous mucosal phytase in monogastric organisms appears incapable of hydrolysing sufficient amounts of phytate-bound P, supplementation of exogenous microbial phytase in diets is a common method to increase mineral and nutrient absorption. Plant phytase activity varies greatly among species of plants, resulting in differing gastrointestinal phytate hydrolysis in monogastric animals. Besides the supplementation of microbial phytase, processing techniques are alternative approaches to reduce phytate contents. Thus, techniques such as germination, soaking and fermentation enable activation of naturally occurring plant phytase among others. However, further research is needed to tap the potential of these technologies. The main focus herein is to review the available literature on the role of phytate in pig and poultry nutrition, its degradation throughout the gut and opportunities to enhance the utilization of P as well as other minerals and nutrients which might be complexed by phytates.

Impact of proton pump inhibitor use on magnesium homoeostasis: a cross-sectional study in a tertiary emergency department

BACKGROUND

To date, the use of proton pump inhibitors (PPIs) has been associated with a low risk of hypomagnesaemia and associated adverse outcomes. We hypothesised that a better risk estimate could be derived from a large cohort of outpatients admitted to a tertiary emergency department (ED).

METHODS

A cross-sectional study was performed in 5118 patients who had measurements of serum magnesium taken on admission to a large tertiary care ED between January 2009 and December 2010. Hypomagnesaemia was defined as a serum magnesium concentration < 0.75 mmol/l. Demographical data, serum electrolyte values, data on medication, comorbidities and outcome with regard to length of hospital stay and mortality were analysed.

RESULTS

Serum magnesium was normally distributed where upon 1246 patients (24%) were hypomagnesaemic. These patients had a higher prevalence of out-of-hospital PPI use and diuretic use when compared with patients with magnesium levels > 0.75 mmol/l (both p < 0.0001). In multivariable regression analyses adjusted for PPIs, diuretics, renal function and the Charlson comorbidity index score, the association between use of PPIs and risk for hypomagnesaemia remained significant (OR = 2.1; 95% CI: 1.54-2.85). While mortality was not directly related to low magnesium levels (p = 0.67), the length of hospitalisation was prolonged in these patients even after adjustment for underlying comorbid conditions (p < 0.0001).

CONCLUSION

Use of PPIs predisposes patients to hypomagnesaemia and such to prolonged hospitalisation irrespective of the underlying morbidity, posing a critical concern.

Gender-specific effects of a phytogenic feed additive on performance, intestinal physiology and morphology in broiler chickens

To date, most studies published were carried out on broilers of the same sex, and possible gender-specific effects of phytogenic substances have not been investigated so far. A 3 × 2 factorial study was performed to examine gender-specific effects of a PFA at two dietary levels (150, 1500 ppm) on growth performance, carcass traits and gastrointestinal attributes in broiler chickens versus an untreated control group. The addition of 150 ppm of the PFA led to a downregulation of trypsinogen mRNA in pancreas compared with the control group (p < 0.05). The number of goblet cells decreased in jejunum compared with the unsupplemented group, whereby this effect was more pronounced in male birds (p < 0.05). Furthermore, higher methylamine contents compared with the control group were measured (p < 0.01). In proximal ileum, female birds, supplemented with 150 ppm PFA, had lower crypt depths than their litters in the 1500 ppm treatment (p < 0.05). In distal ileum, villus height:crypt depth ratio was higher in birds fed the PFA at 150 ppm than in the control group (p < 0.05). The 1500 ppm dosage of the PFA increased jejunal histamine concentration compared with the negative control group (p < 0.05). Jejunal histamine concentration was also affected by the interaction PFA × sex (p < 0.05). Regardless of inclusion level, total amount of biogenic amines and other microbial metabolites in digesta samples was not affected by the PFA. These results demonstrate variable, partially gender-specific effects of the tested PFA. Although the supplementation of 150 ppm showed little effect on mRNA expression level of selected marker genes for nutrient digestion, beneficial effects on gut morphology were observed. The 10-fold higher dosage of the PFA did not adversely affect growth performance as well as most investigated parameters compared with the control group.

D-dimer to rule out pulmonary embolism in renal insufficiency

BACKGROUND

D-dimer levels are often elevated in renal insufficiency. The diagnostic accuracy of D-dimer to rule out pulmonary embolism in patients with renal insufficiency is unclear.

METHODS

We evaluated the data of patients presenting to our Emergency Department and receiving computed tomography angiography to rule out pulmonary embolism with measurement of D-dimer and creatinine. Glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration formula.

RESULTS

There were 1305 patients included; 1067 (82%) had an estimated glomerular filtration rate (eGFR) exceeding 60 mL/min, 209 (16%) 30-60 mL/min, and 29 (2%) <30 mL/min. One hundred fifty-two patients (12%) had D-dimer below 500 μg/L. eGFR (R = -0.1122) correlated significantly with D-dimer (P <.0001). One hundred sixty-nine patients (13%) were found to have pulmonary embolism. Sensitivity of D-dimer for patients with an eGFR >60 mL/min was 96% (confidence interval [CI], 0.93-0.99) and 100% (CI, 100-100) for those with 30-60 mL/min, while specificity decreased significantly with impaired renal function. Area under the curve of the receiver operating characteristic for D-dimer was 0.734 in patients with an eGFR of >60 mL/min, and 0.673 for 30-60 mL/min.

CONCLUSIONS

D-dimer levels were elevated in patients with an eGFR <60 mL/min, but proved to be highly sensitive for the exclusion of pulmonary embolism. However, because almost all patients with impaired renal function had elevated D-dimer irrespective of the presence of pulmonary embolism, studies should be performed to determine renal function-adjusted D-dimer cutoffs.

Electrolyte disorders and in-hospital mortality during prolonged heat periods: a cross-sectional analysis

Background

Heat periods during recent years were associated with excess hospitalization and mortality rates, especially in the elderly. We intended to study whether prolonged warmth/heat periods are associated with an increased prevalence of disorders of serum sodium and potassium and an increased hospital mortality.

Methods

In this cross-sectional analysis all patients admitted to the Department of Emergency Medicine of a large tertiary care facility between January 2009 and December 2010 with measurements of serum sodium were included. Demographic data along with detailed data on diuretic medication, length of hospital stay and hospital mortality were obtained for all patients. Data on daily temperatures (maximum, mean, minimum) and humidity were retrieved by Meteo Swiss.

Results

A total of 22.239 patients were included in the study. 5 periods with a temperature exceeding 25°C for 3 to 5 days were noticed and 2 periods with temperatures exceeding 25°C for more than 5 days were noted. Additionally, 2 periods with 3 to 5 days with daily temperatures exceeding 30°C were noted during the study period. We found a significantly increased prevalence of hyponatremia during heat periods. However, in the Cox regression analysis, prolonged heat was not associated with the prevalence of disorders of serum sodium or potassium. Admission during a heat period was an independent predictor for hospital mortality.

Conclusions

Although we found an increased prevalence of hyponatremia during heat periods, no convincing connection could be found for hypernatremia or disorders of serum potassium.

[Breeding management of black rhinos (Diceros bicornis michaeli) in Magdeburg Zoo]

OBJECTIVE

The African black rhino is an endangered species. In Germany there are only five zoos where this species is kept and breeding has not been successful in all of them. In Magdeburg Zoo the last birth occurred in December 2005, and during the following years, no matings could be observed. During the construction of a new enclosure to enable a more natural mating behaviour, the reproduction status of the rhino cows was evaluated and a hormonal treatment was performed.

MATERIAL AND METHODS

Since 2009, faecal samples from two rhino cows (Diceros bicornis michaeli; "Mana", 30 years old, and "Maleika", 17 years old) were collected periodically, and the pregnanediol-glucuronide (PdG) and oestradiol concentrations were determined using enzyme immunoassay and radioimmunoassay, respectively. Following evaluation of the results, both cows were treated for 12 days with Regumate® Equine, a synthetic progesterone, during the period of PdG-dominance.

RESULTS

"Mana" accepted the bull 11 days after completion of the hormonal treatment, and in December 2011 gave birth to a healthy calf. "Maleika" had her first ever oestrus 13 days after completion of the medication and also accepted the bull. Thereafter, she had two regular oestrus cycles with normal mating behaviour. Her first calf was born in July 2012.

CONCLUSION AND CLINICAL RELEVANCE

The causal treatment of both cows, following a long period of infertility, with synthetic progesterone led to their pregnancy and the birth of healthy calves. The commercial product Regumate® Equine is appropriate to stimulate the sexual cycle in temporarily infertile black rhinos. Attention should be paid to the timing of the medication and the required dose.

Evaporation of free water causes concentrational alkalosis in vitro

BACKGROUND

The development of metabolic alkalosis was described recently in patients with hypernatremia. However, the causes for this remain unknown. The current study serves to clarify whether metabolic alkalosis develops in vitro after removal of free water from plasma and whether this can be predicted by a mathematical model.

MATERIALS AND METHODS

Ten serum samples of healthy humans were dehydrated by 29 % by vacuum centrifugation corresponding to an increase of the contained concentrations by 41 %. Constant partial pressure of carbon dioxide at 40 mmHg was simulated by mathematical correction of pH [pH(40)]. Metabolic acid-base state was assessed by Gilfix' base excess subsets. Changes of acid-base state were predicted by the physical-chemical model according to Watson.

RESULTS

Evaporation increased serum sodium from 141 (140-142) to 200 (197-203) mmol/L, i.e., severe hypernatremia developed. Acid-base analyses before and after serum concentration showed metabolic alkalosis with alkalemia: pH(40): 7.43 (7.41 to 7.45) vs 7.53 (7.51 to 7.55), p = 0.0051; base excess: 1.9 (0.7 to 3.6) vs 10.0 (8.2 to 11.8), p = 0.0051; base excess of free water: 0.0 (- 0.2 to 0.3) vs 17.7 (16.8 to 18.6), p = 0.0051. The acidifying effects of evaporation, including hyperalbuminemic acidosis, were beneath the alkalinizing ones. Measured and predicted acid-base changes due to serum evaporation agreed well.

CONCLUSIONS

Evaporation of water from serum causes concentrational alkalosis in vitro, with good agreement between measured and predicted acid-base values. At least part of the metabolic alkalosis accompanying hypernatremia is independent of renal function.

Diagnostic performance of high-sensitive troponin T in patients with renal insufficiency

In the present study, we wanted to (1) evaluate whether high-sensitive troponin T levels correlate with the grade of renal insufficiency and (2) test the accuracy of high-sensitive troponin T determination in patients with renal insufficiency for diagnosis of acute myocardial infarction (AMI). In this cross-sectional analysis, all patients who received serial measurements of high-sensitive troponin T from August 1, 2010, to October 31, 2012, at the Department of Emergency Medicine were included. We analyzed data on baseline characteristics, reason for referral, medication, cardiovascular risk factors, and outcome in terms of presence of AMI along with laboratory data (high-sensitive troponin T, creatinine). A total of 1,514 patients (67% male, aged 65 ± 16 years) were included, of which 382 patients (25%) had moderate to severe renal insufficiency and significantly higher levels of high-sensitive troponin T on admission (0.028 vs 0.009, p <0.0001). In patients without AMI, high-sensitive troponin T correlated inversely with the estimated glomerular filtration rate (R = -0.12, p <0.0001). Overall, sensitivity of an elevated high-sensitive troponin for diagnosis of AMI was 0.64 (0.56 to 0.71) and the specificity was 0.48 (0.45 to 0.51). The area under the curve of the receiver operating characteristic for all patients was 0.613 (standard error [SE] 0.023), whereas it was 0.741 (SE 0.029) for patients with a Modification of Diet in Renal Disease estimated glomerular filtration rate >60 ml/min presenting with acute chest pain or dyspnea and 0.535 (SE 0.056) for patients with moderate to severe renal insufficiency presenting with acute chest pain or dyspnea. In conclusion, the diagnostic accuracy for presence of AMI of a baseline measurement of high-sensitive troponin in patients with renal insufficiency was poor and resembles tossing a coin.

Bilateral pneumothorax following a blunt trachea trauma

A-13 year old boy had an accident with his bike with a blunt thorax trauma and presented shortly after with facial swelling. Due to respiratory insufficiency, intubation was done during the transport to the clinic. First, a chest radiograph was performed, which showed a unilateral pneumothorax. Later a CT scan revealed bilateral pneumothorax and pneumomediastinum. Bilateral chest tube insertions improved the respiratory situation. Bronchoscopy showed a tracheal lesion two cm posterior to the main carina. After good wound healing, the patient was dismissed after 21 days in good health. Conservative treatment can be recommended in selected patients with a tracheal lesion when having a stable respiratory situation. If the patient does not improve after 48 h or if the clinical condition worsens, surgical management should be considered.

Role of topoisomerase inhibition and DNA repair mechanisms in the genotoxicity of alternariol and altertoxin-II

Alternariol (AOH) and altertoxin-II (ALTX-II) have been demonstrated to possess genotoxic properties. However, the underlying mechanisms of action have not been fully elucidated yet. AOH has recently been shown to act as a topoisomerase I and II poison, contributing to its genotoxic properties. The topoisomerase-specific repair factor tyrosyl-DNA-phosphodiesterase-1 (TDP1) is involved in the respective repair processes of damaged DNA induced by topoisomerase II poison. In the present study, we investigated the role of DNA repair pathways for the extent of DNA damage by AOH and addressed the question whether interference with topoisomerase II might play a role in the genotoxicity of ALTX-II. Under cell-free conditions, AOH and ALTX-II suppressed the activity of topoisomerase II at a comparable concentration range. In HT29 cells, AOH enhanced the level of covalent DNA-topoisomerase II complexes, thus acting as a topoisomerase poison in DNA damaging concentrations. In contrast, ALTX-II in genotoxic concentrations did not show any effect on the stability of these complexes, indicating that interference with topoisomerases does not play a relevant role in genotoxicity. The differences in genotoxic mechanisms seem to be reflected in the activation of p53. AOH was found to increase p53 phosphorylation in HT29 cells in DNA damaging concentrations. In contrast, incubation with ALTX-II did not affect p53 phosphorylation despite substantial increase in tail intensity in the comet assay, suggesting that the DNA lesions formed by ALTX-II are not detected by the DNA-repair machinery of HT29 cells. These results are supported by differences in persistence of DNA damage, still maintained after 24 h for ALTX-II but nearly vanished already after 3 h for AOH. Furthermore, microarray and qPCR analysis did not indicate any substantial impact of AOH on the transcription of key elements of DNA repair pathways. However, siRNA-approaches indicate that, in addition to TDP1, the expression of other elements of the DNA repair machinery exemplified by the 70 kDa Ku autoantigen and the proliferating cell nuclear antigen are relevant for AOH-mediated DNA damage.

Body salt and water balances in cardiothoracic surgery patients with intensive care unit-acquired hyponatremia

PURPOSE

Hyponatremia is frequently observed in intensive care unit (ICU) patients, but there is still lack information on the physiological mechanisms of development.

MATERIALS AND METHODS

In this retrospective analysis we performed tonicity balances in 54 patients with ICU acquired hyponatremia. We calculated fluid and solute in and outputs during 24 hours in 106 patient days with decreasing serum-sodium levels.

RESULTS

We could observe a positive fluid balance as a single reason for hyponatremia in 25% of patients and a negative solute balance in 57%. In 18% both factors contributed to the decrease in serum-sodium. Hyponatremic patients had renal water retention, measured by electrolyte free water clearance calculation in 79% and positive input of free water in 67% as reasons for decline of serum-sodium. The theoretical change of serum sodium during 24 hours according to the calculations of measured balances correlated well with the real change of serum sodium (r = 0.78, P < .01).

CONCLUSIONS

Balance studies showed that renal water retention together with renal sodium loss and high electrolyte free water input are the major contributors to the development of hyponatremia. Control of renal water and sodium handling by urine analysis may contribute to a better fluid management in the ICU population.