Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Genome-wide identification and expression analysis of Polyamine Uptake Transporter gene family in sweet orange (Citrus sinensis)

Polyamine uptake transporter (PUT) plays important roles in polyamine homeostasis, but knowledge regarding PUT family genes in sweet orange (Citrus sinensis) remains elusive. Herein, our study aimed to perform a genome-wide identification of the PUT gene family in C. sinensis. A total of eight putative PUT genes (CsPUT1-CsPUT8) were identified in the sweet orange genome and distributed on three chromosomes. The CsPUT genes were divided into two major groups according to the phylogenetic tree analysis, with high similarities in protein domains and gene structure organization. The CsPUT genes were differentially expressed in different tissues, with the highest transcript levels being in the flowers and roots. Interestingly, the CsPUT genes were significantly induced by polyamines, putrescine, spermidine and spermine, indicating that CsPUT were possibly associated with intracellular polyamine transport and uptake. In addition, CsPUT showed differential expression in callus treated with ABA, cold, salt or osmotic shock. CsPUT4 was selected as a candidate for functional analysis of PUT. Overexpression of CsPUT4 elevated endogenous polyamine content and led to enhanced cold tolerance in transgenic callus cultures. Overall, these data provide valuable information for better understanding the potential biological functions of PUT genes in future.

[Long term results of implantable loop recorder in patients with syncope: results of a French survey]

BACKGROUND AND OBJECTIVE

A first publication of our group demonstrated that implantation of a loop recorder in 30 patients experiencing an unexplained syncope (Medtronic Reveal DX or XT) definitively determined that an arrhythmia was the cause of symptoms in 10 patients (32%). However, we lack the results of a survey evaluating the results of long term follow-up after a loop recorder implantation and the results in case of wider indications of implantation of loop recorders.

METHODS AND RESULTS

A device (Medtronic Reveal DX or XT) was implanted in 97 patients between january 2009 and june 2014. During a mean follow-up of 21±19 months, loop recording determined that an arrhythmia was the cause of symptoms in 34 patients (35%). For the management of these arrhythmias, treatments received by patients were a pacemaker implantation in 18 patients (53%), an implantable cardioverter-defibrillator in four patients (12%) and a supraventricular tachycardia ablation (cryo or radiofrequency ablation) in three patients (9%). For nine patients (26%), the arrhythmic events were asymptomatic and didn't justify a specific treatment. The final positive rate of loop monitoring implantation was of 25/97 (26%). The study demonstrated that the positivity of the follow-up was demonstrated after two years of follow-up in 26% of the cases.

CONCLUSION

Long-term follow-up of 97 patients implanted by a loop monitor leaded to an interventional rythmology procedure in 26% of the cases. In 26% of patients, loop-monitoring follow-up was positive after a duration of more than two years.

[Recovered sudden cardiac death associated with an early repolarization syndrome: case analysis and pratical aspects]

In this article, we report the case of a 61-year-old man who presented a cardiac arrest which has been resuscitated successfully. An early repolarization syndrome has been diagnosed by the ECG recorded the first 3 days after admission. This abnormality disappeared after that. The patient received an implantable cardioverter-defibrillator. Practical messages to the clinician concerning early repolarization are provided in this article.

[Long-term follow-up after implantable loop recorder in patients with syncope: results of a French general hospital survey]

BACKGROUND AND OBJECTIVE

Despite recent advances in diagnostic procedures, syncope remains unexplained in 15 to 35% of patients. If implantable loop recorder is a validated diagnostic tool for unexplained syncope, results of this strategy are largely issued from randomized studies. We lack the results of surveys. The aim of this study was to report a single center experience with implantable loop recorders, in patients with unexplained syncope.

METHODS AND RESULTS

A device (Medtronic Reveal DX or XT) was implanted in 31 patients between January 2009 and January 2012. During a mean follow-up of 10.5±8.5 months, loop recording definitively determined that an arrhythmia was the cause of symptoms in 10 patients (32%). Fourteen patients (45%) experienced syncope or pre-syncope. In eight of the 14 patients with syncope, during follow-up, no arrhythmic diagnosis could be made (one patient has been diagnosed as presenting epilepsy and seven as having hypotensive vasovagal syncope). In six patients, the ILR showed an arrhythmic aetiology. Four other patients presented an abnormal ILR result without symptoms. Diagnosis included sinusal arrest in four patients, bradycardia in one patient, advanced atrioventricular block in two patients, ventricular arrythmias in two patients, and supraventricular tachycardia of 180/min in one patient. Therapy was instituted in all patients, in whom an arrhythmic cause was found except one who refused the therapy (six pacemaker, two implantable cardioverter-defibrillator implantations, and one cryoablation of atrioventricular nodal reentrant tachycardia confirmed by an invasive exploration).

CONCLUSION

In this survey, implantable loop recorder implantation led to the diagnosis of an arrhythmic cause in 32% of patients and excluded an arrhythmic cause in 26% of patient with a mean follow-up of 10.5 months.

[Severe sick sinus syndrome associated with a Werner's syndrome]

A 39-year-old woman was explored for recurrent syncopes. She was already known for a Werner's syndrome with symptoms of aging disorders. The explorations revealed an episode of sinusal arrest. A pacemaker was implanted. This case emphasises the relation between Werner syndrome and the development of cardiovascular abnormalities. This pathology should be recalled in young patients with symptoms of aging disorders and cardiovascular abnormalities. Valvular abnormalities, myocardial infarction and stroke are the major complications of Werner's syndrome. This case indicates that a sick sinus syndrome is a rare but possible complication of Werner's syndrome.

Serum-free generation and quantification of functionally active Leukemia-derived DC is possible from malignant blasts in acute myeloid leukemia and myelodysplastic syndromes

Functional dendritic cells (DC) are professional antigen presenting cells (APC) and can be generated in vitro from leukemic cells from acute myeloid leukemia AML patients, giving rise to APC of leukemic origin presenting leukemic antigens (DC(leu)). We have already shown that DC can be successfully generated from AML and myeloplastic syndromes (MDS) cells in serum-free 'standard' medium (X-vivo + GM-CSF + IL-4 +TNFalpha + FL) in 10-14 days. In this study, we present that DC counts generated from mononuclear cells (MNC) varied between 20% (from 55 MDS samples), 34% (from 100 AML samples) and 25% (from 38 healthy MNC samples) medium. Between 53% and 58% of DC are mature CD83+ DC. DC harvests were highest in monocytoid FAB types (AML-M4/M5, MDS-CMML) and independent from cytogenetic risk groups, demonstrating that DC-based strategies can be applied for patients with all cytogenetic risk groups. Proof of the clonal derivation of DC generated was obtained in five AML and four MDS cases with a combined FISH/immunophenotype analysis (FISH-IPA): The clonal numerical chromosome aberrations of the diseases were regularly codetectable with DC markers; however, not with all clonal cells being convertible to leukemia-derived DC(leu) (on average, 53% of blasts in AML or MDS). To the contrary, not all DC generated carried the clonal aberration (on average, 51% of DC). In 41 AML and 13 MDS cases with a suitable antigen expression, we could confirm FISH-IPA data by Flow cytometry: although DC(leu) are regularly detectable, on average only 57% of blasts in AML and 64% of blasts in MDS were converted to DC(leu). After coculture with DC in mixed lymphocyte reactions (MLR), autologous T cells from AML and MDS patients proliferate and upregulate costimulatory receptors. The specific lysis of leukemic cells by autologous T cells could be demonstrated in three cases with AML in a Fluorolysis assay. In six cases with only few DC(leu) or few vital T cells available after the DC/MLR procedure, no lysis of allogeneic or autologous leukemic cells was seen, pointing to the crucial role of both partners in the lysis process. We conclude: (1) the generation of DC is regularly possible in AML and also in MDS under serum-free conditions. (2) Clonal/leukemia-derived DC(leu) can be regularly generated from MDS and AML-MNC; however, not with all blasts being converted to DC(leu) and not all DC generated carrying leukemic markers. We recommend to select DC(leu) for vaccinations or ex vivo T-cell activations to avoid contaminations with non-converted blasts and non-leukemia-derived DC and to improve the harvest of specific, anti-leukemic T cells. DC and DC-primed T cells could provide a practical strategy for the immunotherapy of AML and MDS.

The value of percutaneous fine needle aspiration cytology under ultrasound guidance in the diagnosis of pancreatic masses

Between September 1996 and May 1999 twenty six pa-tients with a pancreatic mass were studied. In 24 patients (92.3%) the masses could be detected by ultrasound but were not detectable in the other two cases. In the 24 pa-tients percutaneous FN AC under u/s guidance produced only one complication.

The accuracy of this test in diagnosing pancreatic ma-lignant tumours was 90.4%. Laparotomy was not neces-sary in three cases with advanced pancreatic carcinoma (11.5%) and the material aspirated was not suitable for di-agnosis in three cases. No benign lesions were found and so it was not possible to estimate the reliability of FN AC in their diagnosis.

Role of target antigen in bispecific-antibody-mediated killing of human glioblastoma cells: a pre-clinical study

Bispecific antibodies (bsAbs) directed to tumor-associated antigens and to receptors mediating T-cell activation, such as the TCR/CD3 complex and the co-stimulatory CD28 molecule, are capable of activating T cells at the surface of tumor cells, resulting in tumor-cell killing. Here we report the pre-clinical characterization of bispecific-antibody fragments (bsFab2) directed to 2 different glioblastoma-associated antigens: the EGF receptor (EGFR) and a chondroitin-sulfate proteoglycan (CSPG). Using cultured glioblastoma cells expressing both target antigens, we found that the ability of anti-tumor x anti-CD28 bsFab2 to mediate "targeted T-cell co-stimulation" is superior for constructs targeting the CSPG molecule, correlating with an approximately 6-fold higher expression level of this antigen on the cell surface. In contrast, bsFab2 triggering CD3 are more effective if they contain EGFR-target specificity. This indicates that the activity of anti-tumor x anti-CD3 constructs critically depends on properties of the antigen other than its expression level on the cell surface, e.g., its mobility in the membrane. These findings prompted us to use EGFR-targeting bsFab2 in an ongoing clinical trial with glioma patients.

Inhibitory effect of heparin on neutrophil phagocytosis and burst production using a new whole-blood cytofluorometric method for determination

The influence of heparin on Polymorphonuclear (PMN s) leukocytes was investigated using a new whole-blood cytofluorometric method (patent granted for the test with the number P 4334935.8-41) with Candida albicans and Staphylococcus aureus as test microorganisms. After comparing the effect of equal volumes of two widely used heparins we examined the influence of 5 different heparin-concentrations. Using both yeasts and bacteria, we found a significant, dose-depending decrease of the percentage of phagocyting PMN's and of phagocytized microorganisms as well as of the resulting percentage of PMN s producing respiratory burst along the kinetics. Furthermore we could demonstrate that heparin independently of phagocytosis produces a dose-dependent decrease of burst production of PMN's. Our results indicate that the use of heparins as anticoagulant for immunological investigations as well as clinically with patients under immunosuppressive therapy should be critically reconsidered. This applies even more because due to the evaluated dose-dependent decrease of phagocyte function no boundary for the inhibiting effect can be declared.

Immunoassay of O6-methyldeoxyguanosine in DNA: the use of polyethylene glycol to separate bound and free nucleoside

Radioimmunoassay (RIA) method has been established to O6-methyldeoxyguanosine (O6-medGua), using precipitation with polyethylene glycol (PEG) to separate bound and free alkyldeoxyguanosine and antisera of higher affinity (1 x 10(9) M-1) and titre (1:10000) than previously reported. The lower limit of detection (2 S.D. from zero standard) is 40 pg (0.14 pmol) of O6-medGua. Hydrolysates of non-alkylated DNA extracts show interference in the precipitation of antigen-antibody complex, thus making necessary the construction of a standard curve with the same amount of DNA hydrolysates as in the sample to be analysed. Precision of the method was assessed using DNA hydrolysates from livers of rats injected with 15 mg/kg dimethylnitrosamine (DMN). Within assay variation of a single DNA extract was 85.9 +/- 5.9 ng/mg DNA (n = 5, CV = 6.9%). Day-to-day variation of the assay for four DNA extracts measured over 3 days were (ng/mg DNA S.D.), 99.8 +/- 6.9, CV = 6.9%; 88.2 +/- 6.5, CV = 7.4%; 81.3 +/- 3.9, CV = 4.8%; 77.0 +/- 6.4 CV = 8.3%. Coefficient of variation was 10.8% with DNA hydrolysate spiked with a known concentration of O6-medGua and assayed (n = 5). Cross-reactivity of one of our best antisera coded R68/4, and raised against O6-medGua-BSA conjugate were: O6-methylguanosine (O6-meGua), 9.6%; O6-methylguanine (O6-meGua), 0.4%; O6-ethylguanine (O6-EtGua), 0.12%; 7-methylguanosine (7-meGuo), 0.03%; 2'-deoxyadenosine (2'-dAdo), 0.007%; 2'-deoxyguanosine-5'-monophosphoric acid (2'-dGuaMP), 2'-deoxyguanosine (2'-dGua), 7-meGua and 7-meGuo did not significantly inhibit the binding of O6-me[1-2'-3H]dGuo at concentrations of up to 10 micrograms/tube. The application of such methods underline the potential of RIAs for quantification of DNA components structurally modified by non-radioactive carcinogens.

Immunocytochemical and autoradiographic demonstration of prolactin binding to human breast cancer cells in tissue culture

Specific binding of human prolactin to human breast cancer cells in culture was demonstrated for the first time by immunocytochemistry ad autoradiography. Using the former technique, it was found that prolactin binding to the cell surface was heterogeneous: some cells showing intense to moderate peroxidase reaction product and some cells showing absence of reaction product. After the cells were incubated with 125I-labeled prolactin and then embedded in plastic, autoradiography of sections revealed both surface-localized and intracellular silver grains, the latter suggesting internalization of prolactin. These two cytological techniques are useful for visualizing prolactin binding to human breast cancer cells and are applicable to studies on prolactin binding in human breast cancer.