Agreement of pCO2 in venous to arterial blood gas conversion models in undifferentiated emergency patients.

BACKGROUND: Venous blood gas sampling has replaced arterial sampling in many critically ill patients, though interpretation of venous pCO2 still remains a challenge. Lemoël et al., Farkas and Zeserson et al. have proposed models to estimate arterial pCO2 based on venous pCO2. Our objective was to externally validate these models with a new dataset. This was a prospective cross-sectional study of consecutive adult patients with a clinical indication for blood gas analysis in an academic emergency department in Sweden. Agreement of pairs was reported as mean difference with limits of agreement (LoA). Vital signs and lead times were recorded. RESULTS: Two hundred and fifty blood gas pairs were collected consecutively between October 2021 and April 2022, 243 valid pairs were used in the final analysis [mean age 72.8 years (SD 17.8), 47% females]. Respiratory distress was the most common clinical indication (84% of all cases). The model of Farkas showed the best metrics with a mean difference between estimated and arterial pCO2 of - 0.11 mmHg (95% LoA - 6.86, + 6.63). For Lemoël the difference was 2.57 mmHg (95% LoA - 5.65, + 10.8), Zeserson 2.55 mmHg (95% LoA - 7.43, + 12.53). All three models showed a decrease in precision in patients with ongoing supplemental oxygen therapy. CONCLUSION: Arterial pCO2 may be accurately estimated in most patients based on venous blood gas samples. Additional consideration is required in patients with hypo- or hypercapnia or oxygen therapy. Thus, conversion of venous pCO2 may be considered as an alternative to arterial blood gas sampling with the model of Farkas being the most accurate.

A history of anti-racism in scienceThe Remnants of Race Science Sebastián Gil-Riaño Columbia University Press, 2023. 392 pp.

Twentieth-century scientists were imperfect diversity advocates in the Global South.

Risk of venous thromboembolism in patients with COVID-19 during 2020; a retrospective cross-sectional study in a Swedish health care system.

To establish the impact of COVID-19 on the pre-test probability for VTE in patients with suspected VTE. This was a retrospective, observational, cross-sectional study of patients 18 years and older undergoing diagnostic tests for VTE in an integrated healthcare system covering a population of 465,000 during the calendar year of 2020. We adjusted for risk factors such as age, sex, previous VTE, ongoing anticoagulant treatment, malignancy, Charlson score, ward care, ICU care and wave of COVID-19. In total, 303 of 5041 patients had a positive diagnosis of COVID-19 around the time of investigation. The prevalence of VTE in COVID-positive patients was 10.2% (36/354), 14.7% (473/3219) in COVID-19 negative patients, and 15.6% (399/2589) in patients without a COVID-19 test. A COVID-positive status was not associated with an increased risk for VTE (crude odds ratio 0.64, 95% CI 0.45-0.91, adjusted odds ratio 0.46, 95%CI 0.19-1.16). We found no increased VTE risk in COVID-positive patients. This indicates that COVID-19 status should not influence VTE workup.The study was pre-registered on May 26, 2020 at ClinicalTrials.gov with identifier NCT04400877.

Risk of venous thromboembolism in a Swedish healthcare system during the COVID-19 pandemic: A retrospective cross-sectional study.

OBJECTIVE: The objective of this study was to investigate the risk and prevalence of venous thromboembolism (VTE) for patients undergoing a diagnostic test for VTE with confirmed COVID-19 infection compared with patients with no COVID-19 infection. METHODS: This was a retrospective cross-sectional study of patients in an integrated healthcare system in Sweden, covering a population of 465,000, with a diagnostic test for VTE between March 1 and May 31 in the years 2015 to 2020. Risk for VTE with COVID-19 was assessed by logistic regression, adjusting for baseline risk factors. RESULTS: A total of 8702 patients were included, and 88 of those patients tested positive on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction test. A positive SARS-CoV-2 test did not increase the odds for VTE (odds ratio, 0.97; 95% confidence interval [CI], 0.55-1.74) and did not change when adjusting for sex, previous VTE, previous malignancy, Charlson score, hospital admission, intensive care, or ongoing treatment with anticoagulation (odds ratio, 0.72; 95% CI, 0.16-3.3). The prevalence of VTE was unchanged in 2020 compared with 2015 to 2019 (16.5% vs 16.1%, respectively), and there was no difference in VTE between the SARS-CoV-2 positive, negative, or untested groups in 2020 (15.9%, 17.6%, and 15.7%, respectively; P = 0.85). CONCLUSIONS: We found no increased prevalence of VTE in the general population compared with previous years and no increased risk of VTE in patients who were SARS-CoV-2 positive, suggesting that SARS-CoV-2 status should not influence VTE workup in the emergency department. The prevalence of VTE was high in patients with SARS-CoV-2 treated in the intensive care unit (ICU), where the suspicion for VTE should remain high.

Interplay of Matrix Stiffness and c-SRC in Hepatic Fibrosis.

INTRODUCTION: In liver fibrosis activation of hepatic stellate cells (HSC) comprises phenotypical change into profibrotic and myofibroplastic cells with increased contraction and secretion of extracellular matrix (ECM) proteins. The small GTPase RhoA orchestrates cytoskeleton formation, migration, and mobility via non-receptor tyrosine-protein kinase c-SRC (cellular sarcoma) in different cells. Furthermore, RhoA and its downstream effector Rho-kinase also play a crucial role in hepatic stellate cells and hepatic fibrogenesis. Matrix stiffness promotes HSC activation via cytoskeleton modulation. This study investigated the interaction of c-SRC and RhoA under different matrix stiffness conditions. METHODS: Liver fibrosis was induced in rats using bile duct ligation (BDL), thioacetamide (TAA) or carbon tetrachloride (CCl4) models. mRNA levels of albumin, PDGF-R, RHOA, COL1A1, and αSMA were analyzed via qRT-PCR. Western Blots using phospho-specific antibodies against p-c-SRC418 and p-c-SRC530 analyzed the levels of activating and inactivating c-SRC, respectively. LX2 cells and hepatocytes were cultured on acrylamide gels of 1 and 12 kPa or on plastic to mimic non-fibrotic, fibrotic, or cirrhotic environments then exposed to SRC-inhibitor PP2. Overexpression of RhoA was performed by transfection using RhoA-plasmids. Additionally, samples from cirrhotic patients and controls were collected at liver transplantations and tumor resections were analyzed for RhoA and c-SRC protein expression by Western Blot. RESULTS: Transcription of albumin and RhoA was decreased, whereas transcription and activation of c-SRC was increased in hepatocytes cultured on 12 kPa compared to 1 kPa gels. LX2 cells cultured on 12 kPa gels showed upregulation of RHOA, COL1A1, and αSMA mRNA levels. Inhibition of c-SRC by PP2 in LX2 cells led to an increase in COL1A1 and αSMA most prominently in 12 kPa gels. In LX2 cells with RhoA overexpression, c-SRC inhibition by PP2 failed to improve fibrosis. RhoA expression was significantly elevated in human and experimental liver fibrosis, while c-SRC was inactivated. CONCLUSIONS: This study shows that c-SRC is inactive in activated myofibroblast-like HSC in liver cirrhosis. Inactivation of c-SRC is mediated by a crosstalk with RhoA upon hepatic stellate cell activation and fibrosis progression.

Significance of Timing on Effect of Metaphylactic Toltrazuril Treatment against Eimeriosis in Calves.

In this multicentric, randomised, blinded and placebo-controlled field study, the effect of treatment with toltrazuril (Baycox(®) Bovis, Bayer) on oocyst excretion, diarrhoea score and weight gain was studied in Danish dairy herds with confirmed history of eimeriosis (coccidiosis) and prevalence of Eimeria bovis and Eimeria zuernii. Three commercial herds and a total of 71 calves, aged 48 - 135 days, were included. Treatment with a single oral dose of toltrazuril (15 mg/kg) was given after relocation to common pens and one week before expected outbreak of eimeriosis. The effect of treatment was followed by weekly faecal sampling and weighing initially and at the end of a study period of 8 weeks. In Herd 2 and 3 toltrazuril treated calves gained on average 7.95 kg more than placebo treated calves (p = 0.007), and both oocyst excretion and prevalence of Eimeria spp. were significantly reduced the first weeks post treatment. In Herd 1, by contrast, the farmer made some unforeseen changes in the management which entailed relocation to large deep-litter pens 3 - 6 weeks post treatment. In addition, many calves were not treated metaphylactically while few calves excreted oocysts when the trial was initiated. Thus, no significant difference in weight gain was found between toltrazuril and placebo treated calves (p = 0.523), and the oocyst excretion of toltrazuril treated calves was significantly higher during week 7 and 8. Significant differences in faecal scores were observed between the herds (p<0.002) but not between treatment groups in any of the herds. In conclusion, timing of treatment is crucial for optimal effect of metaphylactic toltrazuril treatment on weight gain and oocyst excretion.

The role of everolimus in liver transplantation.

During the last 5 decades, liver transplantation has witnessed rapid development in terms of both technical and pharmacologic advances. Since their discovery, calcineurin inhibitors (CNIs) have remained the standard of care for immunosuppression therapy in liver transplantation, improving both patient and graft survival. However, adverse events, particularly posttransplant nephrotoxicity, associated with long-term CNI use have necessitated the development of alternate treatment approaches. These include combination therapy with a CNI and the inosine monophosphate dehydrogenase inhibitor mycophenolic acid and use of mammalian target of rapamycin (mTOR) inhibitors. Everolimus, a 40-O-(2-hydroxyethyl) derivative of mTOR inhibitor sirolimus, has a distinct pharmacokinetic profile. Several studies have assessed the role of everolimus in liver transplant recipients in combination with CNI reduction or as a CNI withdrawal strategy. The efficacy of everolimus-based immunosuppressive therapy has been demonstrated in both de novo and maintenance liver transplant recipients. A pivotal study in 719 de novo liver transplant recipients formed the basis of the recent approval of everolimus in combination with steroids and reduced-dose tacrolimus in liver transplantation. In this study, everolimus introduced at 30 days posttransplantation in combination with reduced-dose tacrolimus (exposure reduced by 39%) showed comparable efficacy (composite efficacy failure rate of treated biopsy-proven acute rejection, graft loss, or death) and achieved superior renal function as early as month 1 and maintained it over 2 years versus standard exposure tacrolimus. This review provides an overview of the efficacy and safety of everolimus-based regimens in liver transplantation in the de novo and maintenance settings, as well as in special populations such as patients with hepatocellular carcinoma recurrence, hepatitis C virus-positive patients, and pediatric transplant recipients. We also provide an overview of ongoing studies and discuss potential expansion of the role for everolimus in these settings.

RGB marking facilitates multicolor clonal cell tracking.

We simultaneously transduced cells with three lentiviral gene ontology (LeGO) vectors encoding red, green or blue fluorescent proteins. Individual cells were thereby marked by different combinations of inserted vectors, resulting in the generation of numerous mixed colors, a principle we named red-green-blue (RGB) marking. We show that lentiviral vector-mediated RGB marking remained stable after cell division, thus facilitating the analysis of clonal cell fates in vitro and in vivo. Particularly, we provide evidence that RGB marking allows assessment of clonality after regeneration of injured livers by transplanted primary hepatocytes. We also used RGB vectors to mark hematopoietic stem/progenitor cells that generated colored spleen colonies. Finally, based on limiting-dilution and serial transplantation assays with tumor cells, we found that clonal tumor cells retained their specific color-code over extensive periods of time. We conclude that RGB marking represents a useful tool for cell clonality studies in tissue regeneration and pathology.

A novel mechatronic body weight support system.

A novel mechatronic body weight support (BWS) system has been developed to provide precise body weight unloading for patients with neurological or other impairments during treadmill training. The system is composed of a passive elastic spring element to take over the main unloading force and an active closed-loop controlled electric drive to generate the exact desired force. Both force generating units, the passive spring and the active electric drive, act on the patient via a polyester rope connected to a harness worn by the patient. The length of the rope can be adjusted with an electric winch to adapt the system to different patient sizes. The system is fully computer controlled. At unloading loads of up to 60 kg and walking speeds of up to 3.2 km/h, the mean unloading error and the maximum unloading error of the presented BWS system was less than 1 and 3 kg, respectively. The performance was compared with those of two purely passive BWS systems currently being used by most other rehabilitation groups. This comprised counterweight systems and static BWS systems with fixed rope lengths. Counterweight systems reached mean and maximum unloading errors of up to 5.34 and 16.22 kg, respectively. The values for the static BWS were 11.02 kg and 27.67 kg, respectively. The novel mechatronic BWS system presented in this study adjusts desired unloading changes of up to 20 kg within less than 100 ms. Thus, not only constant BWS, but also gait cycle dependent or time variant oscillations of the desired force can be realized with high accuracy. Precise and constant unloading force is believed to be an important prerequisite for BWS gait therapy, where it is important to generate physiologically correct segmental dynamics and ground reaction forces. Thus, the novel BWS system presented in this paper is an important contribution to maximize the therapeutic outcome of human gait rehabilitation.

Manipulation of host hepatocytes by the malaria parasite for delivery into liver sinusoids.

The merozoite stage of the malaria parasite that infects erythrocytes and causes the symptoms of the disease is initially formed inside host hepatocytes. However, the mechanism by which hepatic merozoites reach blood vessels (sinusoids) in the liver and escape the host immune system before invading erythrocytes remains unknown. Here, we show that parasites induce the death and the detachment of their host hepatocytes, followed by the budding of parasite-filled vesicles (merosomes) into the sinusoid lumen. Parasites simultaneously inhibit the exposure of phosphatidylserine on the outer leaflet of host plasma membranes, which act as "eat me" signals to phagocytes. Thus, the hepatocyte-derived merosomes appear to ensure both the migration of parasites into the bloodstream and their protection from host immunity.

The liver stage of Plasmodium berghei inhibits host cell apoptosis.

Plasmodium berghei is the causative agent of rodent malaria and is widely used as a model system to study the liver stage of Plasmodium parasites. The entry of P. berghei sporozoites into hepatocytes has extensively been studied, but little is known about parasite-host interaction during later developmental stages of the intracellular parasite. Growth of the parasite far beyond the normal size of the host cell is an important stress factor for the infected cell. Cell stress is known to trigger programmed cell death (apoptosis) and we examined several apoptotic markers in P. berghei-infected cells and compared their level of expression and their distribution to that of non-infected cells. As none of the apoptotic markers investigated were found altered in infected cells, we hypothesized that parasite infection might confer resistance to apoptosis of the host cell. Treatment with peroxide or serum deprivation induced apoptosis in non-infected HepG2 cells, whereas P. berghei-infected cells appeared protected, indicating that the parasite interferes indeed with the apoptotic machinery of the host cell. To prove the physiological relevance of these results, mice were infected with high numbers of P. berghei sporozoites and treated with tumour necrosis factor (TNF)-alpha/D-galactosamine to induce massive liver apoptosis. Liver sections of these mice, stained for degraded DNA, confirmed that infected cells containing viable parasites were protected from programmed cell death. However, in non-treated control mice as well as in TNF-alpha-treated mice a small proportion of dead intracellular parasites with degraded DNA were detected. Most hepatocytes containing dead parasites provoked an infiltration of immunocompetent cells, indicating that these cells are no longer protected from cell death.

Prolactin triggers pro-inflammatory immune responses in peripheral immune cells.

The peptide hormone prolactin (PRL) is produced by specialized cells in the anterior pituitary gland and in a number of sites outside the pituitary. Its biological actions consist of various roles in reproduction, lactation, and of a number of homeostatic biological activities that also include immune functions. Elevated serum PRL concentrations often correlate with abnormalities in immune responses. To determine the influence of PRL on human immune cells, human whole blood cultures were stimulated with lipopolysaccharide (LPS), supplemented with various concentrations of human recombinant PRL. We found that PRL, at concentrations achievable during pregnancy, anesthesia and medication, significantly amplified interleukin (IL)-12 and tumor necrosis factor-alpha (TNF-alpha) synthesis in LPS-stimulated cultures, in a dose-dependent manner. Conversely, synthesis of the anti-inflammatory cytokine IL-10 only increased significantly at very high concentrations of supplemented PRL. PRL alone was not able to induce any measurable secretion of TNF-alpha, IL-10, or IL-12 in non-stimulated, whole blood cultures. However, we demonstrated that PRL, by itself or in combination with LPS, causes an increase in the binding activity of the transcription factors nuclear factor-kappaB (NFkappaB) and interferon regulatory factor-1 (IRF-1), which are known to promote TNF-alpha and IL-12 secretion. These data suggest that PRL promotes pro-inflammatory immune responses via NFkappaB and IRF-1, which may affect pathophysiological processes in physiological hyperprolactinemic states.

Monitoring of a new approach of immunotherapy with allogenic (111)In-labelled NK cells in patients with renal cell carcinoma.

The transfusion of allogenic, in vitro expanded natural killer cells (NKC) is a novel therapy option in oncology. To date, however, the biodistribution and kinetics of allogenic NKC have not been investigated. Therefore, in this study three patients with renal cell carcinoma received 3-7 x 10(8) NKC labelled with indium-111 oxine with a tenfold excess of unlabelled cells during NKC therapy. Whole-body scintigrams were obtained (0.5-144 h) in the anterior and posterior views. Scintigrams were analysed using a region of interest technique, and single-photon emission tomography (SPET) studies of the abdomen were performed. Results were compared to those obtained with polymerase chain reaction (PCR) of the peripheral blood (determination of foreign DNA, nested PCR, limit of detection 0.01%). Shortly after transfusion of NKC, more than 50% of the activity was accumulated in the lungs. We observed redistribution effects from lungs to liver, spleen and bone marrow. No significant loss of activity could be detected. In two of four large metastases, tracer accumulation could be proven by SPET. As confirmed by scintigrams and PCR, the fraction of circulating transfused cells was low at all times. Long-term activity retention might be caused either by survival of the allogenic cells, as confirmed by PCR (up to 3 days p.i.), or by phagocytosis of labelled cellular fragments. However, PCR data and uptake in metastases indicated long survival of a portion of allogenic NKC. Such long survival and low retention of the cells in the lung are requirements for an effective immunotherapeutic approach.

Early alterations in the number of circulating lymphocyte subpopulations and enhanced proinflammatory immune response during opioid-based general anesthesia.

The balance between proinflammatory and anti-inflammatory processes is of key importance in the reaction of the body to infection, injury, and surgical trauma. Drugs commonly used in anesthesia and intensive care may modulate immunological reactions by influencing intercellular communication through modification of cytokine response and fluctuation of peripheral immune cells such as natural killer (NK) cells, B cells, and T lymphocyte subpopulations (CD4+ and CD8+ cells). To examine the effects of general anesthesia with the hypnotic agent propofol and the opioid fentanyl, 30 patients undergoing minor elective orthopedic surgery were studied before and 20 min after application of the anesthetic drugs, but before the start of surgery. We found a significant enhancement of TNF-alpha and IL-1beta release in lipopolysaccharide (LPS)-stimulated whole blood cultures after induction of anesthesia. Similar results were observed with interferon-gamma (IFN-gamma) in cultures stimulated with phytohemagglutinin (PHA). Conversely, synthesis of the anti-inflammatory cytokine interleukin 10 (IL-10) decreased significantly in LPS-stimulated cultures. During general anesthesia, we found a decrease of circulating lymphocytes, characterized by a significant increase in the percentage of T lymphocytes in favor of CD4+ cells, increased B lymphocytes, and a significant decrease of NK cells. These data suggest that anesthesia with propofol and fentanyl promotes proinflammatory immune responses and influences peripheral lymphocyte composition in patients, which may subsequently affect pathophysiological processes during opioid-based anesthesia.

Probability of anti-D development in D- patients receiving D+ RBCs.

BACKGROUND: In some situations, the administration of D+ RBCs to D- patients is necessary. The probability of a subsequent anti-D formation is assumed to be around 80 percent, a figure based primarily on studies in healthy volunteers. It was hypothesized that patients requiring blood transfusion have a much lower probability of developing antibodies. STUDY DESIGN AND METHODS: A retrospective analysis was performed whereby 78 D- patients were evaluated for the development of RBC antibodies after administration of D+ RBCs. For the analysis of the cross-sectional observations, parametric models were used for interval-censored data. RESULTS: Anti-D was detected in 16 of 78 patients. Considering the individual patient's inspection times, the calculated probability of developing antibody following D+ RBC supply was shown to be below 41.7 percent (upper 95% confidence bound) and estimated as 30.4 percent. The data hinted toward an inverse correlation between the number of transfused units and the probability of antibody formation. Interestingly, 6 of these 16 patients developed additional IgG autoantibody. In 3 of those cases, evidence for prolonged hemolysis was found. CONCLUSION: The actual frequency of antibody formation in our patients is much lower than assumed. On the other hand, prolonged hemolysis probably induced by additional autoreactive antibodies might occur. This possible complication has not yet been addressed. Further studies might reveal whether a less restricted transfusion policy with respect to D matching is justified in selected patients.

Prolactin induces enhanced interferon gamma release in peripheral whole blood after stimulation with either PHA or LPS.

A number of recent studies have demonstrated the importance of prolactin as a key mediator in immune-neuroendocrine communication. Using a whole blood assay and various concentrations of prolactin, we stimulated cell cultures with either the plant lectin PHA or the endotoxin LPS, a widespread agent in common infectious diseases. Studying 15 healthy blood donors we found that human recombinant prolactin, at concentrations from 5 ng/ml to 100 ng/ml, significantly amplified IFN-gamma yields after stimulation with either PHA or LPS. PHA-stimulated cultures revealed a significant dose-dependent enhancement of IFN-gamma release. Our results indicate that prolactin can upregulate IFN-gamma secretion from immune cells in whole blood cell cultures in response to both PHA or LPS. Since IFN-gamma is suspected to play a key role in the cytokine cascade, amplifying the toxic effect of other pro-inflammatory cytokines and ultimately leading to augmented inflammatory tissue damage, our findings point to a modulatory role of prolactin in infection. Special interest should therefore be directed towards any naturally occurring hyperprolactinemia, caused for instance by stress, a number of drugs, and some chronic diseases.

Large-scale generation of natural killer lymphocytes for clinical application.

Natural killer (NK) lymphocytes can be used for adoptive immunotherapeutic strategies. Alternatively, they may be employed as adjuvants for stem cell/bone marrow transplantation, either to re-induce remission, or to purge autografts of contaminating malignant cells. We developed a new protocol that enables the generation of NK cells on a clinical scale in a closed system that enables good manufacturing practice (GMP) conformity. Aside from the initial NK cell inoculum, our protocol includes activated feeder cells [irradiated peripheral blood mononuclear cells (PBMC) and no transformed blasts], cytokines [interleukin-2 (IL-2) and IL-15], human serum, and a complex basic media formulation. During the whole expansion period of approximately 14 days, the cells were handled in PTFE (Teflon) bags, whereby fresh medium was added without opening the system. The use of immortalized or virus-transformed feeder cells, as used in many other current research protocols, was completely avoided. A precise controlling of a number of environmental factors was necessary to achieve reproducible results. Increases in NK cell number ranged between 80- and 200-fold. The resulting NK cells were CD56(+), CD3(-), and CD16(+) (75%). They were highly cytotoxic against different malignant target cells and did not produce significant levels of interferon-gamma. Therefore, they belonged to the cytotoxic rather than the immunoregulatory NK subpopulation. No non-specific activation against normal allogenous lymphocytes occurred. This work might permit the realization of future protocols for evaluating the clinical effect of NK lymphocytes in human disease.