Large-Area Epitaxial Mott Insulating 1T-TaSe2 Monolayer on GaP(111)B.

Two-dimensional Mott materials have recently been reported in the dichalcogenide family with high potential for Mottronic applications. Nevertheless, their widespread use as a single or few layers is hampered by their limited device integration resulting from their growth on graphene, a metallic substrate. Here, we report on the fabrication of 1T-TaSe2 monolayers grown by molecular beam epitaxy on semiconducting gallium phosphide substrates. At the nanoscale, the charge density wave reconstruction and a moiré pattern resulting from the monolayer interaction with the substrate are observed by scanning tunneling microscopy. The fully open gap unveiled by tunneling spectroscopy, which can be further manipulated by the proximity of a metal tip, is confirmed by transport measurements from micrometric to millimetric scales, demonstrating a robust Mott insulating phase at up to 400 K.

Outcomes of renal replacement therapy in the critically ill with COVID-19.

OBJECTIVE: To describe outcomes of critically ill patients with COVID-19, particularly the association of renal replacement therapy to mortality. DESIGN: A single-center prospective observational study was carried out. SETTING: ICU of a tertiary care center. PATIENTS: Consecutive adults with COVID-19 admitted to the ICU. INTERVENTION: Renal replacement therapy. MAIN VARIABLES OF INTEREST: Demographic data, medical history, illness severity, type of oxygen therapy, laboratory data and use of renal replacement therapy to generate a logistic regression model describing independent risk factors for mortality. RESULTS: Of the total of 166 patients, 51% were mechanically ventilated and 26% required renal replacement therapy. The overall hospital mortality rate was 36%, versus 56% for those requiring renal replacement therapy, and 68% for those with both mechanical ventilation and renal replacement therapy. The logistic regression model identified four independent risk factors for mortality: age (adjusted OR 2.8 [95% CI 1.8-4.4] for every 10-year increase), mechanical ventilation (4.2 [1.7-10.6]), need for continuous venovenous hemofiltration (2.3 [1.3-4.0]) and C-reactive protein (1.1 [1.0-1.2] for every 10 mg/L increase). CONCLUSIONS: In our cohort, acute kidney injury requiring renal replacement therapy was associated to a high mortality rate similar to that associated to the need for mechanical ventilation, while multiorgan failure necessitating both techniques implied an extremely high mortality risk.

OBJETIVO: Describir los resultados de pacientes críticamente enfermos con COVID-19, especialmente la asociación de la terapia de reemplazo renal con la mortalidad. DISEÑO: Estudio observacional, prospectivo y unicéntrico. ÁMBITO: En la unidad de cuidados intensivos (UCI) de un centro de atención terciaria. PACIENTES: Pacientes adultos con COVID-19 ingresados de forma consecutiva en la UCI. INTERVENCIÓN: Administración de terapia de reemplazo renal. VARIABLES DE INTERÉS PRINCIPALES: Datos demográficos, antecedentes médicos, gravedad de la enfermedad, tipo de oxigenoterapia, datos analíticos y uso de terapia de reemplazo renal para generar un modelo de regresión logística que describa factores de riesgo independientes de la mortalidad. RESULTADOS: De los 166 pacientes, el 51% recibieron ventilación mecánica (VM) y el 26% requirió terapia de reemplazo renal (TRR). La mortalidad hospitalaria global fue del 36%, frente al 56% en el caso de los pacientes que requirieron TRR y el 68% en el subconjunto de pacientes que necesitó tanto VM como RTT. Un modelo de regresión logística señala cuatro factores de riesgo independientes de la mortalidad: edad (OR ajustada: 2,8 [IC del 95%: 1,8-4,4] por cada incremento de 10 años), ventilación mecánica (4,2 [1,7-10,6]), necesidad de hemofiltración venovenosa continua (HVVC) (2,3 [1,3-4,0]), y proteína C reactiva (1,1 [1,0-1,2] por cada incremento de 10 mg/L). CONCLUSIONES: En nuestra cohorte, la lesión renal aguda que necesita TRR se asocia con una mortalidad similarmente elevada a la de los pacientes que requieren VM, y la insuficiencia multiorgánica que hace necesarias ambas intervenciones se asocia con un riesgo de mortalidad extremadamente alta.

Glial cell line-derived neurotrophic factor (GDNF) induced migration of spermatogonial cells in vitro via MEK and NF-kB pathways.

Glial cell line-derived neurotrophic factor (GDNF) regulates spermatogonial stem cell (SSC) maintenance. In the present study, we examined the levels and the cellular origin of GDNF in mouse testes during age-development, and the capacity of GDNF to induce migration of enriched GFR-α1 positive cells in vitro. The involvement of MAP kinase (MEK) and NF-kB signal pathways were examined. Our results show high levels of GDNF in testicular tissue of one-week-old mice which significantly decreased with age when examined by ELISA, real time PCR (qPCR) and immunofluorescence staining (IF) analysis. GDNF receptor (GFR-α1) expression was similar to GDNF when examined by qPCR analysis. Only Sertoli cell cultures (SCs) from one-week-old mice produced GDNF compared to SCs from older mice. However, peritubular cells from all the examined ages did not produce GDNF. The addition of recombinant GDNF (rGDNF) or supernatant from SCs from one-week-old mice to GFR-α1 positive cells induced their migration in vitro. This effect was significantly reduced by the addition of inhibitors to MEK (PD98059, U0126), NF-kB (PDTC) and IkB protease inhibitor (TPCK). Our results show for the first time the capacity of rGDNF and supernatant from SCs to induce migration of enriched GFR-α1 positive cells, and the possible involvement of MEK, NF-kB and IkB in this process. This study may suggest a novel role for GDNF in the regulation SSC niches and spermatogenesis.

Progesterone inhibits arterial smooth muscle cell proliferation.

Mortality from atherosclerotic cardiovascular disease is lower in premenopausal women than in age-matched men. It is also lower in postmenopausal women who take estrogens and progestins together rather than estrogens alone. Progesterone receptors were detected in human and rat aortic smooth muscle cells in vivo and in vitro (in subculture). We examined the effect of progesterone on proliferation of smooth muscle cells, important constituents of atherosclerotic plaques. Progesterone at physiologic levels inhibited DNA synthesis and proliferation in these cells in a dose-dependent manner, and pretreatment with the progesterone receptor antagonist RU486 blocked inhibition. Cyclin A and E messenger RNA levels decreased after progesterone treatment but those of cyclin B and D1 did not change. This cell cycle-dependent inhibition of arterial smooth muscle cell proliferation by progesterone may represent a mechanism for the hormone's protective effect against atherosclerosis.

Outcomes of renal replacement therapy in the critically ill with COVID-19.

OBJECTIVE: To describe outcomes of critically ill patients with COVID-19, particularly the association of renal replacement therapy to mortality. DESIGN: A single-center prospective observational study was carried out. SETTING: ICU of a tertiary care center. PATIENTS: Consecutive adults with COVID-19 admitted to the ICU. INTERVENTION: Renal replacement therapy. MAIN VARIABLES OF INTEREST: Demographic data, medical history, illness severity, type of oxygen therapy, laboratory data and use of renal replacement therapy to generate a logistic regression model describing independent risk factors for mortality. RESULTS: Of the total of 166 patients, 51% were mechanically ventilated and 26% required renal replacement therapy. The overall hospital mortality rate was 36%, versus 56% for those requiring renal replacement therapy, and 68% for those with both mechanical ventilation and renal replacement therapy. The logistic regression model identified four independent risk factors for mortality: age (adjusted OR 2.8 [95% CI 1.8-4.4] for every 10-year increase), mechanical ventilation (4.2 [1.7-10.6]), need for continuous venovenous hemofiltration (2.3 [1.3-4.0]) and C-reactive protein (1.1 [1.0-1.2] for every 10mg/L increase). CONCLUSIONS: In our cohort, acute kidney injury requiring renal replacement therapy was associated to a high mortality rate similar to that associated to the need for mechanical ventilation, while multiorgan failure necessitating both techniques implied an extremely high mortality risk.

Peritoneal macrophage depletion by liposomal bisphosphonate attenuates endometriosis in the rat model.

BACKGROUND: Activation of macrophages is central to the implantation of endometriosis (EM). We examined the hypothesis that macrophage depletion by intraperitoneal (IP) injection of liposomal alendronate (LA) could result in EM attenuation in a rat model, thus supporting the notion of the pivotal role of macrophages in EM pathology. METHODS: In this study, 90 rats were subjected to an EM model and were divided randomly into seven groups: five groups were treated by 4x once-weekly IP injections of LA (0.02, 0.1, 1, 5 or 10 mg/kg) and the other two groups received saline injections (control) or empty liposomes. Sham-operated rats also received empty liposomes. Depletion of circulating monocytes was determined by flow cytometry analyzes of blood specimens. Four weeks after the initial surgery, the number, size and weight of implants were recorded, adhesions were graded, macrophage infiltration was assessed and the peritoneal fluid was analyzed for monocyte chemotactic protein 1 (MCP-1) and tumor necrosis factor alpha (TNFalpha). RESULTS: Monocyte depletion following IP LA administration resulted in an inhibitory effect on the initiation and growth of EM implants, as expressed by implantation rate, adhesion scoring, implants' size and weight (>0.1 mg/kg LA, P < 0.05). Reduced numbers of infiltrating macrophages were observed in implants of the 1 mg/kg LA group. Peritoneal fluid MCP-1 levels were negatively correlated with LA dose (P < 0.001), whereas no significant correlation could be found for TNFalpha. CONCLUSIONS: Macrophage depletion using IP LA has been shown to effectively inhibit the initiation and growth of EM implants, in a rat EM model. The clear dose-response effect may be viewed as a confirmation of the validity of the concept and encourages further study.

Activated platelets form protected zones of adhesion on fibrinogen and fibronectin-coated surfaces.

Leukocytes form zones of close apposition when they adhere to ligand-coated surfaces. Because plasma proteins are excluded from these contact zones, we have termed them protected zones of adhesion. To determine whether platelets form similar protected zones of adhesion, gel-filtered platelets stimulated with thrombin or ADP were allowed to adhere to fibrinogen- or fibronectin-coated surfaces. The protein-coated surfaces with platelets attached were stained with either fluorochrome-conjugated goat anti-human fibrinogen or anti-human fibronectin antibodies, or with rhodamine-conjugated polyethylene glycol polymers. Fluorescence microscopy revealed that F(ab')2 anti-fibrinogen (100 kD) did not penetrate into the contact zones between stimulated platelets and the underlying fibrinogen-coated surface, while Fab antifibrinogen (50 kD) and 10 kD polyethylene glycol readily penetrated and stained the substrate beneath the platelets. Thrombin- or ADP-stimulated platelets also formed protected zones of adhesion on fibronectin-coated surfaces. F(ab')2 anti-fibronectin and 10 kD polyethylene glycol were excluded from these adhesion zones, indicating that they are much less permeable than those formed by platelets on fibrinogen-coated surfaces. The permeability properties of protected zones of adhesion formed by stimulated platelets on surfaces coated with both fibrinogen and fibronectin were similar to the zones of adhesion formed on fibronectin alone. mAb 7E3, directed against the alpha IIb beta 3 integrin blocked the formation of protected adhesion zones between thrombin-stimulated platelets and fibrinogen or fibronectin coated surfaces. mAb C13 is directed against the alpha 5 beta 1 integrin on platelets. Stimulated platelets treated with this mAb formed protected zones of adhesion on surfaces coated with fibronectin. These protected zones were impermeable to F(ab')2 antifibronectin but were permeable to 10 kD polyethylene glycol. These results show that activated platelets form protected zones of adhesion and that the size of molecules excluded from these zones depends upon the composition of the matrix proteins to which the platelets adhere. They also show that formation of protected zones of adhesion by platelets requires alpha IIb beta 3 integrins while the permeability properties of these zones of adhesion are regulated by both alpha IIb beta 3 and alpha 5 beta 1 integrins.

Production of antibody to tetanus toxoid by continuous human lymphoblastoid cell lines.

Peripheral lymphocytes from human volunteers boosted with tetanus toxoid were cultured after in vitro infection with Epstein-Barr virus. Forty-four continuous lymphoblastoid lines were established which continued to secrete human gamma globulin; seven of these secreted antibody to tetanus toxoid. Subcultures derived from limiting dilution experiments continued to secrete the antibody. Some of these antibody-secreting cells have been in continuous culture for more than 6 months.

Monoclonal antibodies to a synthetic fibrin-like peptide bind to human fibrin but not fibrinogen.

A synthetic heptapeptide from the amino terminus of the beta chain in human fibrin was used as an antigen to produce monoclonal antibodies that bind to fibrin even in the presence of human fibrinogen at the concentration found in plasma. As expected, the antifibrin activity was inhibited by the peptide antigen but not by a control heptapeptide. In a chicken ex vivo circulatory model for fibrin detection, intravenously administered monoclonal antibodies bound to human fibrin-coated disks placed in an extracorporeal chamber. These findings may lead to better methods for identifying deep vein and coronary artery thrombi.

Antibody-directed urokinase: a specific fibrinolytic agent.

A specific fibrinolytic agent was synthesized by covalently coupling urokinase to a monoclonal antibody that was fibrin-specific and did not cross-react with fibrinogen. The antibody was raised against a synthetic peptide representing the seven amino-terminal residues of the beta chain of human fibrin. The urokinase-antifibrin conjugate retained the original binding specificity of the antibody and showed 100-fold increased fibrinolysis in vitro when compared to unmodified urokinase. The presence of human fibrinogen at plasma concentration did not influence these properties.

Innovative approaches to plasminogen activator therapy.

Plasminogen activator therapy for acute myocardial infarction has become standard medical practice. Bleeding complications, however, limit the utility of the currently available agents. This article reviews how the tools of molecular biology and protein engineering are being used to develop safer and more effective plasminogen activators.

Antibodies to pneumococcal polysaccharides: relation between binding and electrophoretic heterogeneity.

Antibodies to type III and type VIII pneumococcal polysaccharides were examined with respect to ligand binding and electrophoretic heterogeneity. Both antibodies showed apparent binding homogeneity, although multiple light chain and heavy chain electrophoretic species were demonstrated.

Inhibition of angiotensin conversion in experimental renovascular hypertension.

Constriction of the renal artery and controlled reduction of renal perfusion pressure is followed by a prompt increase in systemic renin activity and a concomitant rise in blood pressure in trained, unanesthetized dogs. The elevated blood pressure induced by the renal artery stenosis can be prevented by prior treatment with the nonapeptide Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro, which blocks conversion of angiotensin I to angiotensin II. Further, the nonapeptide can restore systemic pressure to normnal in the early phase of renovascular hypertension. These results offer strong evidence that the renin-angiotensin system is responsible for the initiation of hypertension in the unilaterally nephrectomized dog with renal artery constriction.

Renin-specific antibody for study of cardiovascular homeostasis.

Antiserum specific for purified canine renal renin was used to inhibit this enzyme in trained, conscious dogs. The antiserum did not affect blood pressure in sodium-replete dogs but decreased plasma renin activity and blood pressure in sodium-depleted animals. The antiserum also reduced blood pressure to control levels concomitant with suppression of plasma renin activity in uninephrectomized dogs with acute renovascular hypertension. These observations establish the role of the renin-angiotensin system in the maintenance of blood pressure in the sodium-depleted state as well as in the initiation of renovascular hypertension.

Myocardial infarct imaging of antibodies to canine cardiac myosin with indium-111-diethylenetriamine pentaacetic acid.

Antibodies, by virtue of marked selectivity and affinity, may lend themselves to identification of structures of unique antigenic specificity in vivo. In experimental myocardial infarction in dogs, F(ab')2 fragments of antibodies to cardiac myosin that had been labeled with iodine-131 were shown to localize within the lesion. Because the energy characteristics of iodine isotopes are not ideal for imaging with a gamma camera, a new method for labeling antibody fragments with divalent or polyvalent radionuclides was developed. A bifunctional chelating agent, diethylenetriamine pentaacetic acid was covalently coupled, by an amide bond, to Fab fragments of antibodies to canine cardiac myosin. A stable chelate was then formed with indium-111, a nuclide that has appropriate half-life and energy characteristics for gamma imaging. Antibodies treated in this way retain their antigen-binding activity and are useful in locating myocardial infarcts in vivo.

Myocardial injury: quantitation by cell sorting initiated with antimyosin fluorescent spheres.

Spheres coated with antibodies specific for myosin were used to detect myocardial cell membrane disruption by scanning electron microscopy. Injury in a population of cultured myocytes as then followed and measured by fluorescence-activated cell sorting. This approach provides a unique method for quantitating the evolution of myocardial injury and potentially for assessing the efficacy of interventions aimed at myocardial protection.

The structure of rat preproatrial natriuretic factor as defined by a complementary DNA clone.

The structure of rat preproatrial natriuretic factor ( preproANF ) was determined by nucleotide sequence analysis of an ANF complementary DNA clone. PreproANF is composed of a hydrophobic leader segment (20 amino acids), a precursor containing one glycosylation site (106 amino acids), and ANF (24 amino acids). Atrial natriuretic factor is located at the carboxyl terminus of the precursor molecule. The human, mouse, and rat genomes each contain a single ANF gene which is highly conserved.

Digoxin intoxication: the relationship of clinical presentation to serum digoxin concentration.

A radioimmunoassay for serum digoxin concentration has been used to study the interrelationships of circulating levels of the drug and various factors in the clinical setting in 48 hospitalized patients with cardiac rhythm disturbances due to digoxin intoxication. 131 patients on maintenance doses of digoxin without toxicity and 48 patients with equivocal evidence of digoxin excess were also studied and compared with the toxic group. Patients with cardiac rhythm disturbances due to digoxin intoxication tended to be older and to have diminished renal function compared with the nontoxic group; body weight, serum potassium concentration, underlying cardiac rhythm, and nature of cardiac disease were not significantly different for the groups as a whole. Despite comparable mean daily digoxin dosages, digoxin intoxicated patients had a mean serum digoxin concentration of 3.7 +/-1.0 (SD) ng/ml, while nontoxic patients had a mean level of 1.4 +/-0.7 ng/ml (P < 0.001), 90% of patients without evidence of toxicity had serum digoxin concentrations of 2.0 ng/ml or less, while 87% of the toxic group had levels above 2.0; the range of overlap between the two groups extended from 1.6 to 3.0 ng/ml. Patients with atrioventricular block as their principal toxic manifestation had a significantly lower mean serum digoxin concentration than those in whom ectopic impulse formation was the chief rhythm disturbance. Patients with equivocal evidence of digoxin excess had received comparable daily maintenance doses of digoxin but had a mean serum concentration of 1.9 +/-0.8 ng/ml, intermediate between those of the nontoxic (P < 0.005) and toxic (P < 0.001) groups. Renal function as judged by mean blood urea nitrogen concentration was also intermediate. The data indicate that knowledge of the serum digoxin concentration, weighed in the clinical context, is useful in the management of patients receiving this drug.

An antiidiotypic antibody that recognizes the beta-adrenergic receptor.

Antialprenolol rabbit antibodies were fractionated on an acebutolol affinity resin, followed by L-propranolol elution so as to separate a class of binding sites that mimic the beta-adrenergic receptor. Allotype-identicaL rabbits were immunized with this fraction. After 6 mo, antisera exhibited antiidiotypic activity inhibiting [3H]alprenolol binding to the original antibody and to rabbit antiacebutolol antibodies, which had a spectrum of ligand-binding properties identical to the original idiotype. Those antisera demonstrating the original idiotype. Those antisera demonstrating the most potent antiidiotypic activity also blocked [3H]alprenolol binding to the beta-adrenergic receptor of turkey membrane, canine pulmonary membrane, and rat reticulocyte. An idiotype affinity-purified fraction showed similar activity, inhibiting beta-receptor binding with a calculated dissociation constant (KD) of 53 nM. Isoproterenol-mediated adenylate cyclase activity was also inhibited in a competitive manner. The universality of recognition of these antiidiotypic antisera indicate that the three-dimensional structure of a receptor's binding site can be modeled by a subset of an elicited antibody population.

Localization of cardiac myosin-specific antibody in myocardial infarction.

Specific localization of purified antibody against cardiac myosin has been demonstrated in areas of altered myocardial membrane permeability after experimental myocardial infarction. Intravenously administered radioiodine-labeled antimyosin was selectively localized in infarcted myocardium of seven dogs 24 h after coronary occlusion. The mean ratio (+/-SE) of antimyosin antibody in infarcted to normal myocardium in the center of the infarct was 4.2+/-0.4 for endocardial and 2.9+/-0.3 for epicardial layers. By utilizing (Fab')2 fragments of antimyosin obtained by pepsin digestion of purified antibody, the ratio of uptake was increased in eight dogs to 6.1+/-0.6 in the endocardial and 3.3+/-0.4 in the epicardial layers at the infarct center 24 h after occlusion. These ratios were further increased in the infarct center to 13.8+/-1.2 in the endocardial and 7.3+/-0.8 in the epicardial layers when eight dogs were sacrificed 72 h after coronary occlusion. The specificity of antimyosin (Fab')2 localization in infarcted myocardium was demonstrated in four dogs by simultaneous intravenous administration of 125I-labeled antimyosin (Fab')2 and 131I-labeled normal rabbit gamma globulin (Fab')2. Nonspecific trapping of normal rabbit IgG (Fab')2 was observed to be about 38% of total antimyosin (Fab')2 uptake in the central zone of infarction. Regional blood flow was related to antimyosin (Fab')2 uptake in infarcted myocardium by utilizing simultaneous administration of 85Sr-labeled microspheres. An inverse exponential relationship between antimyosin (Fab')2 uptake and regional blood flow was observed (r=0.85). The specific localization of antimyosin antibody or its (Fab')2 components in infarcted myocardium suggests a conceptually new approach to myocardial infarct localization and sizing.