GPR37 is processed in the N-terminal ectodomain by ADAM10 and furin.

GPR37 is an orphan G protein-coupled receptor (GPCR) implicated in several neurological diseases and important physiological pathways in the brain. We previously reported that its long N-terminal ectodomain undergoes constitutive metalloprotease-mediated cleavage and shedding, which have been rarely described for class A GPCRs. Here, we demonstrate that the protease that cleaves GPR37 at Glu167↓Gln168 is a disintegrin and metalloprotease 10 (ADAM10). This was achieved by employing selective inhibition, RNAi-mediated downregulation, and genetic depletion of ADAM10 in cultured cells as well as in vitro cleavage of the purified receptor with recombinant ADAM10. In addition, the cleavage was restored in ADAM10 knockout cells by overexpression of the wild type but not the inactive mutant ADAM10. Finally, postnatal conditional depletion of ADAM10 in mouse neuronal cells was found to reduce cleavage of the endogenous receptor in the brain cortex and hippocampus, confirming the physiological relevance of ADAM10 as a GPR37 sheddase. Additionally, we discovered that the receptor is subject to another cleavage step in cultured cells. Using site-directed mutagenesis, the site (Arg54↓Asp55) was localized to a highly conserved region at the distal end of the ectodomain that contains a recognition site for the proprotein convertase furin. The cleavage by furin was confirmed by using furin-deficient human colon carcinoma LoVo cells and proprotein convertase inhibitors. GPR37 is thus the first multispanning membrane protein that has been validated as an ADAM10 substrate and the first GPCR that is processed by both furin and ADAM10. The unconventional N-terminal processing may represent an important regulatory element for GPR37.

Slowly fading super-luminous supernovae that are not pair-instability explosions.

Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate.

The Parkinson's-disease-associated receptor GPR37 undergoes metalloproteinase-mediated N-terminal cleavage and ectodomain shedding.

The G-protein-coupled receptor 37 ( GPR37) has been implicated in the juvenile form of Parkinson's disease, in dopamine signalling and in the survival of dopaminergic cells in animal models. The structure and function of the receptor, however, have remained enigmatic. Here, we demonstrate that although GPR37 matures and is exported from the endoplasmic reticulum in a normal manner upon heterologous expression in HEK293 and SH-SY5Y cells, its long extracellular N-terminus is subject to metalloproteinase-mediated limited proteolysis between E167 and Q168. The proteolytic processing is a rapid and efficient process that occurs constitutively. Moreover, the GPR37 ectodomain is released from cells by shedding, a phenomenon rarely described for GPCRs. Immunofluorescence microscopy further established that although full-length receptors are present in the secretory pathway until the trans-Golgi network, GPR37 is expressed at the cell surface predominantly in the N-terminally truncated form. This notion was verified by flow cytometry and cell surface biotinylation assays. These new findings on the GPR37 N-terminal limited proteolysis may help us to understand the role of this GPCR in the pathophysiology of Parkinson's disease and in neuronal function in general.

Identification of antibacterial peptides from endophytic microbiome.

Endophytes, microorganisms living inside plant tissues, are promising producers of lead compounds for the pharmaceutical industry. However, the majority of endophytes are unculturable and therefore inaccessible for functional studies. To evaluate genetic resources of endophytes, we analyzed the biodiversity of fungal microbiome of black crowberry (Empetrum nigrum L.) by next-generation sequencing and found that it consists mainly of unknown taxa. We then separated the host and the endophyte genomes and constructed a fosmid expression library from the endophytic DNA. This library was screened for antibacterial activity against Staphylococcus aureus. A unique antibacterial clone was selected for further analysis, and a gene En-AP1 was identified with no similarity to known sequences. The expressed, folded protein En-AP1 was not active against S. aureus, while tryptic digests exhibited antimicrobial activity. Seven out of twelve synthesized peptides, predicted antibacterial in silico, exhibited in vitro activity towards both S. aureus and Escherichia coli. We propose that the En-AP1 protein is degraded in the library host E. coli and antimicrobial fragments are released from the cell, explaining the in vitro antibacterial activity of the clone. This is the first report of a novel gene expressed in vitro derived from an endophytic microbiome, demonstrating the potential of finding novel genes and compounds from unculturable endophytes.

A giant outburst two years before the core-collapse of a massive star.

The death of massive stars produces a variety of supernovae, which are linked to the structure of the exploding stars. The detection of several precursor stars of type II supernovae has been reported (see, for example, ref. 3), but we do not yet have direct information on the progenitors of the hydrogen-deficient type Ib and Ic supernovae. Here we report that the peculiar type Ib supernova SN 2006jc is spatially coincident with a bright optical transient that occurred in 2004. Spectroscopic and photometric monitoring of the supernova leads us to suggest that the progenitor was a carbon-oxygen Wolf-Rayet star embedded within a helium-rich circumstellar medium. There are different possible explanations for this pre-explosion transient. It appears similar to the giant outbursts of luminous blue variable stars (LBVs) of 60-100 solar masses, but the progenitor of SN 2006jc was helium- and hydrogen-deficient (unlike LBVs). An LBV-like outburst of a Wolf-Rayet star could be invoked, but this would be the first observational evidence of such a phenomenon. Alternatively, a massive binary system composed of an LBV that erupted in 2004, and a Wolf-Rayet star exploding as SN 2006jc, could explain the observations.

A dust-enshrouded tidal disruption event with a resolved radio jet in a galaxy merger.

Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 1052 erg at infrared and radio wavelengths but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.

Unfavourable short-term outcomes of a poly-L/D-lactide scaffold for thumb trapeziometacarpal arthroplasty.

The bioabsorbable poly-L-D-lactide joint scaffold arthroplasty is a recent attempt in the reconstruction of small joints in rheumatoid patients. In this study, we analysed the 1-year clinical, functional and radiologic results of partial trapeziectomy with the poly-L-D-lactide (96/4) joint scaffold in 23 patients with isolated trapeziometacarpal osteoarthritis. The results showed that the procedure provided pain relief and improvement in overall function according to the Quick Disabilities of the Arm, Shoulder and Hand score in most patients. However, radiographs demonstrated a high frequency of osteolysis around the implant. Seven patients developed clinically manifested foreign-body reactions 6 months to 1 year after surgery. The reason for the unexpected tissue reactions may relate to excessive mechanical cyclic loading of the implant. The outcomes of this implant in our patients have not been sufficiently beneficial and we have discontinued use of this implant in isolated trapeziometacarpal osteoarthritis.

Lack of correlation between serum dopamine-beta-hydroxylase activity and blood pressure in middle-aged men.

The activity of serum dopamine-beta-hydroxylase (DBH) was measured in 1194 asymptomatic middle-aged men with diastolic blood pressure ranging from 75 to 125 mm Hg during the baseline examination of a multifactorial intervention program for primary prevention of coronary heart disease. No correlation was present between serum DBH activity and systolic (r = -0.01, NS) or diastolic (r = +0.02, NS) blood pressure. No significant differences in serum DBH activity was observed between individuals with blood pressure in the lower, middle or upper deciles. Serum DBH activity was similar in subjects with normal blood pressure, in individuals with widely fluctuating blood pressure and in patients with fixed hypertension. The results suggest that serum DBH activity cannot be used as an aid in the diagnosis of essential hypertension of middle-aged men.

Effect of long-term antihypertensive and hypolipidemic treatment on high density lipoprotein cholesterol and apolipoproteins A-I and A-II.

The concentrations of total serum cholesterol and triglycerides and serum HDL cholesterol, triglycerides and apoproteins A-I and A-II were measured in 119 men after 4 years of active participation in a multifactorial primary prevention trial of coronary heart disease. No difference was observed in total serum cholesterol, triglycerides, HDL lipids or apoproteins between the control subjects without medication and the men treated with antihypertensive drugs (beta-blockers alone or in combination with thiazides). The concentration of HDL cholesterol was significantly lower and that of apoprotein A-II significantly higher in the individuals treated with clofibrate than in the controls. On the other hand, the levels of both HDL cholesterol and apoprotein A-I were lower in the men treated with probucol than in the controls, whereas that of A-II was within the control limits. The ratio HDL cholesterol/apoprotein A-I was subnormal in all 3 groups treated with lipid-lowering drugs, as if the treatment had lowered the cholesterol saturation of the HDL fraction. The levels of HDL cholesterol and apoprotein A-I were negatively correlated with the length of the treatment in subjects treated with probucol but not in the other groups. These results suggest that in long-term use, probucol and possibly clofibrate lower both the concentration and the cholesterol/apoprotein ratio of the HDL fraction.

Abnormal in vivo response to sodium nitroprusside after porcine single lung transplantation.

The chronic increase of pulmonary vascular resistance after lung transplantation is only partly due to an active increase in baseline vasomotor tone, but the nature of the acute pulmonary hypertension after ischemia and reperfusion is not known. We studied the effects of sodium nitroprusside on pulmonary hemodynamics during reperfusion in porcine left lung allotransplants. In twelve pigs (weight: 18 to 24 kg) pulmonary arteries of the native and the transplanted lung were cannulated for right-heart bypass. The total blood flow was 2 L/min. Flow distribution between the lungs was measured at equal mean pulmonary artery pressure, and pulmonary vascular resistance at equal and constant flow-i.e., 1 L/min to each lung. After baseline measurements sodium nitroprusside (1, 3, and 9 microg/kg/min) was administered to six animals (SNP group). The control group (n=6) received an equal amount of the vehicle. After 30 min of discontinuation of the drug infusion, the schedule was repeated. In the transplanted lung, pulmonary vascular resistance decreased in all animals during the first hour of reperfusion. During the second drug infusion pulmonary vascular resistance was significantly lower in the SNP group compared with the control group only at the highest infusion rate of the drug (9 microg/kg/min), which also induced a 44% decrease in systemic vascular resistance. Arterial oxygen tension remained comparable in the two groups throughout the study. Our data suggest that other factors besides active vasoconstriction may contribute to the acute increase of pulmonary vascular resistance after lung transplantation.

The correlation between symptomatic CMV infection and CMV antigenemia in heart allograft recipients.

Previous studies have demonstrated that CMV-specific antigens detected from peripheral blood leukocytes correlate with active CMV infection in transplant patients. However, the clinical diagnosis of CMV infection is difficult, and the significance of a positive blood finding is unclear, while CMV antigenemia and viremia may also occur in asymptomatic patients. To investigate the clinical significance of CMV antigenemia after heart transplantation, 68 heart allograft recipients were monitored weekly. Altogether 501 blood specimens were analyzed. CMV was demonstrated in blood leukocytes by a monoclonal antibody and immunoperoxidase staining, and the antigenemia level was expressed as CMV positive cells/50,000 leukocytes. CMV antigenemia occurred in 28/68 patients, and 12 of them developed a symptomatic infection. Of all blood specimens 88/501 were CMV positive, and 30 of them related to the clinical manifestation of CMV. When antigenemia level exceeded > 100/50,000, a significant correlation between antigenemia and CMV-related clinical manifestation was reached (P < 0.001). Of the 28 antigenemia positive patients 16 never developed any clinical signs of CMV infection. Their maximal antigenemia level was low (median 23, range 30-90) compared with those with clinical manifestation (median 500, range 30-1000) (P < 0.002). In conclusion, high antigenemia levels (> 100/50,000) correlate with clinical manifestations of CMV infection. Patients with lower levels (< 100/50,000) do not necessarily ever develop a symptomatic infection. Quantitative monitoring of CMV antigenemia may, thus, be helpful in the clinical diagnosis of CMV infection in heart transplant patients.

Single lung allotransplantation in pigs. A morphologic study of tissue preservation with modified Euro-Collins and fluorocarbon solutions.

In the present study the functional and morphologic effects of two pulmoplegic solutions are evaluated. Single left-lung allotransplantation with ligation of the right pulmonary artery was performed in 15 piglets (13-20 kg). The lungs were preserved after donor prostaglandin E-1 treatment with single pulmonary artery flush with either modified Euro-Collins solution (mECS) (9 pigs) or oxygenated fluorocarbon emulsion (FC-43) (6 pigs) and transplanted after 6-hr storage in cold Physiosol solution. Tidal volumes of 15 ml/kg x fr (18) with 40% inspired oxygen were used for ventilation during reperfusion. Function of the transplanted lung was monitored for 4 hr postoperatively by determining pa CO2 and pa O2 levels from arterial samples and by noninvasive monitoring of end-tidal CO2 values and arterial oxygen saturations. Sequential morphologic changes in pulmonary artery flow surface and lung tissue were studied after 6-hr storage and 4-hr reperfusion, using light, scanning, and transmission electron microscopy (LM, SEM, TEM). There was no mortality. After transplantation the mECS group experienced significant hypoxia and hypercarbia and had low end-tidal CO2 values as signs of defective oxygenation and gas exchange, whereas the FC-43 group was normoxic and normoventilated without disturbed elimination of carbon dioxide. After storage and reperfusion, LM showed signs of increased vascular permeability and reperfusion damage--more evident in the mECS group compared with the FC-43 group--while the lymphoid cell population was more intensely activated in the latter group. Electron microscopy after storage showed good overall preservation of structures in both groups. After reperfusion preservation of pulmonary artery flow surface and lung tissue was estimated to be moderate in the mECS group, whereas it was good-to-moderate in the FC-43 group by SEM (NS). TEM of lung tissue, however, showed significantly better-preserved alveolar epithelial lining in the FC-43 group compared with the mECS group. In conclusion, oxygenated fluorocarbon (FC-43) pulmoplegia gave better functional and morphologic preservation of lung grafts compared with modified Euro-Collins solution.

Traumatic rupture of the pericardium with luxation of the heart. Case report and review of the literature.

A report is made of a case of left diaphragmatic and pericardial rupture with luxation of the heart from the pericardial sac, resulting from a steering wheel injury. The patient was successfully treated surgically. In the treatment of this injury, correcting the hemodynamic derangement caused by incarceration and torsion of the heart is stressed. A review of the literature on pericardial ruptures is presented.

Polydioxanone and polypropylene suture material in free internal mammary artery graft anastomoses.

An experimental study with six beagle dogs was conducted to evaluate a new monofilamentous absorbable suturing material--polydioxanone. Free internal mammary artery grafts, 3 cm long, were harvested via a median sternotomy and were implanted as arterial bypasses in femoral arteries (12 end-to-end anastomoses) and as arteriovenous shunts in the carotid artery-contralateral jugular vein position (12 end-to-side anastomoses). Twenty-four anastomoses were made with monofilamentous nonabsorbable suturing material, polypropylene (12 arterial, 12 shunts), to serve as control grafts. At 6 months the grafts and anastomoses were explanted and studied with light and scanning electron microscopes. Macroscopically, the polydioxanone sutures had disappeared. The major histologic finding was the foreign body reaction around the polypropylene sutures. In the electron microscopic study the endothelial line covered the anastomotic site and in the polypropylene anastomoses the suture material was bulging up from the anastomoses. No aneurysms or dilatations were seen. According to this study, polydioxanone is a suitable suturing material for small luminal arterial anastomoses and is superior to polypropylene suturing material because it causes no tissue or other late changes on the flow surfaces.

Management of delayed esophageal perforation with mediastinal sepsis. Esophagectomy or primary repair?

Ninety patients with esophageal perforations were operated on at our institutions between 1970 and 1992. Thirty-four of them were seen after delayed diagnosis (> 24 hours) with mediastinal sepsis caused by perforation of the thoracic esophagus. There were 18 patients with spontaneous ruptures, 11 with instrumental perforations (including one caused during laparotomy), and 3 perforations caused by foreign bodies. One patient had perforation of an esophageal ulcer into the pericardium and another had perforation of an esophageal diverticulum into the mediastinum. Nineteen patients underwent primary repair of the perforation with cleansing and drainage of the mediastinum and the pleural cavity. The remaining 15 had primary extirpation of the thoracic esophagus, irrigation of the mediastinum with antibiotics, cervical esophagostomy, gastrostomy, and drainage of the mediastinum and pleural cavity. Nineteen of the 34 patients survived (hospital mortality 44%). Of patients with primary repair, only six survived (in-hospital mortality 68%), whereas only two patients treated with esophagectomy died (in-hospital mortality 13%). The difference was highly significant (p = 0.001). The most common cause of death was multiorgan failure resulting from sepsis. Postoperative complications developed in four patients treated with primary repair (two sepsis, one empyema, and one anuria) and in seven patients treated with esophagectomy (two empyema, two sepsis, one pneumonia, one mediastinal abscess, and one brain abscess). After healing of the mediastinitis, the esophagogastric continuity was reconstructed with colon in 11 patients and stomach in two patients. In the management of delayed esophageal perforation with mediastinal sepsis, esophagectomy is superior to primary repair alone, which often leads to mediastinal leakage, continued sepsis, and death.

Pulmonary vasodilatory properties of prostaglandin E1 are blunted after experimental single lung transplantation.

BACKGROUND: Pulmonary dysfunction and right heart failure are still a common clinical problem after single lung transplantation. METHODS: In this study we investigated the pulmonary vasodilatory properties of prostaglandin E1 in pigs during the first 4 hours after left lung allotransplantation. With the use of extracorporeal circulation and total right heart bypass, the right and left pulmonary arteries could be individually perfused and the drug effect in each lung separately analyzed either at equal blood pressures or at equal blood flows in the pulmonary arteries. Twelve animals received in a randomized double-blind fashion either saline solution or an increasing prostaglandin E1 infusion (10, 25, 50, and 100 ng/kg/min; 15 minutes each). After a drug-free period of 75 minutes, the infusion schedule with 25, 50, and 100 ng/kg/min was repeated. RESULTS: During the first part of the study the highest dose of prostaglandin E1 decreased the mean systemic arterial pressure by 25%, but an almost similar decrease occurred in the control animals. During the second infusion period a 28% decrease was observed only in the animals treated with prostaglandin E1. None of the infusions was able to decrease pulmonary vascular resistance. Instead prostaglandin E1 diverted two thirds of the pulmonary blood flow toward the native lung, and this diversion manifested itself as an earlier improvement of the arterial oxygen tension in the drug-treated animals. The end-tidal carbon dioxide values measured from each lung corresponded to those from the common expiratory limb of the system, but there was a distinct gradient in the range of 14 to 20 mm Hg between the arterial and end-tidal carbon dioxide values. CONCLUSIONS: We conclude that prostaglandin E1, in doses tolerated by the systemic circulation, is ineffective in the treatment of the increased pulmonary vascular resistance after single lung transplantation.

Endothelialitis and accelerated arteriosclerosis in human heart transplant coronaries.

We have analyzed the autopsy material of 11 cardiac allograft recipients, whose grafts became nonfunctional less than 1 year after transplantation. All patients had received routine triple-drug immunosuppression. Two of these patients showed accelerated transplant arteriosclerosis; the graft loss was associated with strong intimal proliferative response affecting the first-order and second-order intramuscular branches of the major coronary vessels. Histologic evidence showed only a slight inflammatory reaction in the vascular adventitia. The media was mostly intact, and the internal elastic lamina showed occasional breaks. A very prominent inflammatory reaction was noted in the subendothelial space in the intima. Immunohistochemistry with monoclonal antibodies revealed that the luminal part of the intima was invaded by anti-leukocyte common antigen and anti-UCHL1 positive T lymphocytes, whereas the abluminal part consisted mostly of anti-smooth muscle alpha-actin-positive smooth muscle cells. We call this subendothelial accumulation of lymphocytes endothelialitis. The suggestion has been made that accelerated arteriosclerosis may be associated with cyclosporine treatment. Correlation with the recipient's cytomegalovirus status in this study suggests that cytomegalovirus infection may contribute to the development of endothelialitis and accelerated arteriosclerosis in heart transplant recipients.

Thromboxane receptor blockade does not attenuate pulmonary pressor response in porcine single lung transplantation.

BACKGROUND: The ischemia-reperfusion lung injury is characterized by increased pulmonary vascular resistance, edema, and subsequent deterioration of oxygenation. Other models of acute lung injury suggest that thromboxane A2 may contribute to the pulmonary hypertension after transplantation. METHODS: We studied the effects of the selective thromboxane A2 receptor antagonist SQ 30741 on pulmonary hemodynamics and gas exchange in porcine single lung transplantation using extracorporeal circulation (right heart bypass) with separate cannulations of the right and left pulmonary arteries. Pulmonary vascular resistance was measured at equal and constant flow to each lung. Flow distribution between the lungs was registered at equal pulmonary artery pressures. Twelve pigs (weight 17 to 23 kg) were studied. At the onset of reperfusion a bolus dose of the drug (5 mg/kg) was injected into both pulmonary arteries followed by an infusion (5 mg/kg/hr) for 1 hour (SQ group, n = 6). The control group (n = 6) received an equal amount of vehicle. The systemic and pulmonary hemodynamics and blood gas values were registered during 2 hours of reperfusion. RESULTS: The pulmonary vascular resistance of the transplanted lung was significantly higher compared with the native lung (p < 0.001). Administration of SQ 30741 failed to ameliorate the pulmonary pressor response of the graft in comparison with the control group. No difference was found in the systemic arterial oxygen tension between the two groups. CONCLUSIONS: Thromboxane does not seem to be among the principal mediators in the pulmonary hypertension after transplantation.

Heart transplant rejection treated with plasmapheresis.

The vascular element of a mixed type of rejection after orthotopic heart transplantation did not respond to steroid therapy in a 30-year-old man. Plasmapheresis was associated with the resolution of the clinical signs of rejection and the microscopic changes of vasculitis in the biopsy specimen. This case suggests that plasmapheresis may be useful in the treatment of acute vascular rejection in heart transplantation.