Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice

Dobutamine is a β-adrenergic agonist with an affinity higher for receptor expressed in the heart (β₁) than for receptors expressed in the arteries (β₂). When systemically administered, it increases cardiac demand. Thus, dobutamine unmasks abnormal rhythm or ischemic areas potentially at risk of infarction. Monitoring of heart function during a cardiac stress test can be performed by either ecocardiography or cardiac catheterization. The latter is an invasive but more accurate and informative technique that the former.Cardiac stress test induced by dobutamine and monitored by cardiac catheterization accomplished as described here allows, in a single experiment, the measurement of the following hemodynamic parameters: heart rate (HR), systolic pressure, diastolic pressure, end-diastolic pressure, maximal positive pressure development (dP/dtmax) and maximal negative pressure development (dP/dt_min), at baseline conditions and under increasing doses of dobutamine.As expected, in normal mice we observed a dobutamine dose-related increase in HR, dP/dt_max and dP/dt_min. Moreover, at the highest dose tested (12 ng/g/min) the cardiac decompensation of high fat diet-induced obese mice was unmasked.     

Increasing incidence and survival of corpus uteri cancer in Estonia over the past two decades

BackgroundCorpus uteri cancer has become the fourth most common female cancer in Europe. In Estonia, the prevalence of obesity is increasing, and corpus uteri cancer survival has been relatively low. The aim of the study was to evaluate incidence, mortality and survival trends of corpus uteri cancer in Estonia by age, stage and histological subtypes with an emphasis on surgical treatment.MethodsEstonian Cancer Registry data on incident cases of corpus uteri cancer were used to examine incidence trends (1995–2016) and calculate relative survival ratios (RSR) (1996–2016). Cases were classified by morphology and FIGO stage. Causes of Death Registry data were used to analyse corrected mortality (1995–2017).ResultsA total of 4281 cases were diagnosed in 1996–2016. A significant increase was seen in age-standardized incidence from 2009, while mortality remained stable throughout the study period. Significant increases were observed for type I cancers and age groups ≥65 years. Overall age-standardized 5-year RSR improved from 70% in 1996–2002 to 78% in 2010–2016. Survival increased for type I cancers, all age groups and all stages (significantly for stage IV). The proportion of surgically treated cases increased significantly from 85% to 89%, with the largest increases seen in older age groups and later stages.DiscussionThe rising corpus uteri cancer incidence in Estonia is driven by the type I cancer trend. Survival gain for later stages and older age groups likely reflected more frequent surgical treatment. To reduce mortality, further efforts are necessary to ensure appropriate care for all patients.     

In vivo Measurement of the Mouse Pulmonary Endothelial Surface Layer

The endothelial glycocalyx is a layer of proteoglycans and associated glycosaminoglycans lining the vascular lumen. In vivo, the glycocalyx is highly hydrated, forming a substantial endothelial surface layer (ESL) that contributes to the maintenance of endothelial function. As the endothelial glycocalyx is often aberrant in vitro and is lost during standard tissue fixation techniques, study of the ESL requires use of intravital microscopy. To best approximate the complex physiology of the alveolar microvasculature, pulmonary intravital imaging is ideally performed on a freely-moving lung. These preparations, however, typically suffer from extensive motion artifact. We demonstrate how closed-chest intravital microscopy of a freely-moving mouse lung can be used to measure glycocalyx integrity via ESL exclusion of fluorescently-labeled high molecular weight dextrans from the endothelial surface. This non-recovery surgical technique, which requires simultaneous brightfield and fluorescent imaging of the mouse lung, allows for longitudinal observation of the subpleural microvasculature without evidence of inducing confounding lung injury.     

Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation

Cryoballoon ablation (CBA) is an established therapy for atrial fibrillation (AF). Pulmonary vein (PV) occlusion is essential for achieving antral contact and PV isolation and is typically assessed by contrast injection. We present a novel method of direct pressure monitoring for assessment of PV occlusion.Transcatheter pressure is monitored during balloon advancement to the PV antrum. Pressure is recorded via a single pressure transducer connected to the inner lumen of the cryoballoon. Pressure curve characteristics are used to assess occlusion in conjunction with fluoroscopic or intracardiac echocardiography (ICE) guidance. PV occlusion is confirmed when loss of typical left atrial (LA) pressure waveform is observed with recordings of PA pressure characteristics (no A wave and rapid V wave upstroke). Complete pulmonary vein occlusion as assessed with this technique has been confirmed with concurrent contrast utilization during the initial testing of the technique and has been shown to be highly accurate and readily reproducible.We evaluated the efficacy of this novel technique in 35 patients. A total of 128 veins were assessed for occlusion with the cryoballoon utilizing the pressure monitoring technique; occlusive pressure was demonstrated in 113 veins with resultant successful pulmonary vein isolation in 111 veins (98.2%). Occlusion was confirmed with subsequent contrast injection during the initial ten procedures, after which contrast utilization was rapidly reduced or eliminated given the highly accurate identification of occlusive pressure waveform with limited initial training.Verification of PV occlusive pressure during CBA is a novel approach to assessing effective PV occlusion and it accurately predicts electrical isolation. Utilization of this method results in significant decrease in fluoroscopy time and volume of contrast.     

Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies

Critical to the evaluation of potential therapeutics for muscular disease are sensitive and reproducible physiological assessments of muscle function. Because many pre-clinical trials rely on mouse models for these diseases, isolated muscle function has become one of the standards for Go/NoGo decisions in moving drug candidates forward into patients. We will demonstrate the preparation of the extensor digitorum longus (EDL) and diaphragm muscles for functional testing, which are the predominant muscles utilized for these studies. The EDL muscle geometry is ideal for isolated muscle preparations, with two easily accessible tendons, and a small size that can be supported by superfusion in a bath. The diaphragm exhibits profound progressive pathology in dystrophic animals, and can serve as a platform for evaluating many potential therapies countering fibrosis, and promoting myofiber stability. Protocols for routine testing, including isometric and eccentric contractions, will be shown. Isometric force provides assessment of strength, and eccentric contractions help to evaluate sarcolemma stability, which is disrupted in many types of muscular dystrophies. Comparisons of the expected results between muscles from wildtype and dystrophic muscles will also be provided. These measures can complement morphological and biochemical measurements of tissue homeostasis, as well as whole animal assessments of muscle function.     

Orthotopic allotransplantation and autotransplantation of the baboon heart following 24-hr storage by a portable hypothermic perfusion system

A nonpulsatile perfusion apparatus, based on the air-lift pump principle, has been developed. Circulation of the perfusate, as well as oxygenation and maintenance of acid-base balance, is provided by the flow of a mixture of 97% oxygen and 3% carbon dioxide. The system is easily and entirely portable. Eleven baboons underwent orthotopic allotransplantation with donor hearts stored by continuous hypothermic (4-10 degrees C) perfusion for periods of up to 24 hr. Three were electively killed after 2 to 3 days; the remaining eight, immunosuppressed with methylprednisolone and either azathioprine or cyclosporin A, survived to rejection at between 10 and 49 days. Cardiac catheterization performed in six animals 7-14 days after allotransplantation showed virtually normal hemodynamic data. Three more baboons underwent heart excision and storage by hypothermic perfusion for 24 hr, and subsequent othotopic autotransplantation, the circulation of the baboon being maintained in the interim by an allograft. One animal survives 8 months later with hemodynamic data at cardiac catheterization differing little from that obtained before autotransplantation. This perfusion system has subsequently been used to store four human donor hearts prior to heterotopic transplantation.     

东方大黄蜂的表皮异源移植试验

将东方大黄蜂（胡蜂）蛹或幼蜂的棕色表皮层连同含有黑色素的皮细胞层、黄色表皮层及相连的产生黄嘌呤的皮细胞层割下，换化后植入原来的黄蜂体上（原来是黄色的部分用棕色替代，棕色的用黄色替代）。然后将蛹放回原来的子脾中，幼蜂放入一特殊的培养皿中，让其复原和发育。共对200个不同时期的蛹和50只幼蜂进行了试验。结果显示，存活的最主要是将羽化的蛹（差1—2天就羽化的蛹），早期的蛹和幼蜂均死亡。总共有约5％的蛹存活，幼蛹无一存活。在存活的蛹中，棕色表皮植入黄色区域中的不但成活了，而且还保留了棕色色彩。相反，黄色表皮在植入到棕色区域的几天后，就丢失了黄色及膜片。经过表皮异源移植的大黄蜂寿命极短，一般仅几星期。羽化后较敏感，攻击性强，但行走、飞行都很正常[动物学报51（6）：1146—1150，2005]。     

In vitro growth of murine T cells. IV. Use of T-cell growth factor to clone lymphoid cells

Murine bone marrow cells can suppress the in vitro primary antibody response of normal spleen cells without apparent cytotoxicity. The bone marrow cells suppress the response to both T-dependent (SRBC) and T-independent (DNP-Ficoll) antigens. When bone marrow cells are fractionated on a sucrose density gradient, the suppressive activity is found in the residue rather than the lymphocyte fraction. The suppressive activity is either unaffected or enhanced by treatment with anti-T- and anti-B-cell serums. Pretreatment of mice with phenylhydrazine which reduces the number of pre-B cells did not reduce the suppressive activity of their bone marrow cells. Suppressive activity is abolished by irradiation of the marrow cells in vitro with 1000 R prior to assay. The activity is present in the marrow of thymus deficient (nude) mice, infant mice, and mice which have been made polycythemic by transfusion. Furthermore, the suppressor cell can phagocytize iron carbonyl particles, is slightly adherent to plastic and Sephadex G-10, and can bind to EA monolayers. We conclude that the suppressor cell is not a mature lymphocyte or granulocyte nor a member of the erythrocytic series, but is likely to be an immature cell possibly of the myeloid series. We speculate on the physiologic role of this cell.