Coexpression of the membrane glycoproteins G1 and G2 of Hantaan virus is required for targeting to the Golgi complex.

To study the intracellular transport and targeting to the Golgi complex of the membrane glycoproteins G1 and G2 of Hantaan virus, we have expressed them together and separately using recombinant vaccinia viruses. When expressed from the same recombinant vaccinia virus, G1 and G2 were localized to the Golgi complex as analyzed by both immunofluorescence and subcellular fractionation. However, when the glycoproteins were expressed from separate recombinant viruses, both proteins remained in the endoplasmic reticulum. Using several monoclonal antibodies, it was found that G1 expressed alone did not acquire its correct conformation. Finally, if cells were coinfected with G1- and G2-expressing recombinant viruses, the proteins were again targeted to the Golgi complex. The N-linked glycans remained in all cases largely endoglycosidase-H sensitive. With none of the recombinant viruses were expression of the glycoproteins observed on the cell surface. Neither did chasing in the presence of cycloheximide result in the surface expression of G1 or G2. Our results indicate that for transport out of the endoplasmic reticulum and proper targeting to the Golgi complex, the two glycoproteins have to be coexpressed. The most likely interpretation is that G1 and G2 have to interact with each other in the endoplasmic reticulum in order to become transport competent.     

Characterisation of Dopamine and Serotonin Uptake Inhibitory Effects of Tetrahydroaminoacridine in Rat Brain

Abstract: The effects of 1,2,3,4-tetrahydro-9-aminoacridine (THA) on uptake rates of radioactive 5-hydroxytryptamine (5-HT) and dopamine were investigated in rat diencephalon and striatal homogenates, respectively. Six and eight μM of THA were needed to inhibit 50% of dopamine and 5-HT uptake rates. Kinetic parameters, K_m and V_max, using six different concentrations of dopamine and 5-HT were estimated in the presence or absence of THA. A significant decrease in V_max without any change in K_m values was observed for both dopamine and 5-HT in the presence of THA. The results show that THA is a non-competitive uptake inhibitor of dopamine and 5-HT in the nerve terminals. The re-uptake blocking effect of THA on dopaminergic and serotonergic neurones, following THA treatment, might lead to increased levels of these monoamines in brains of Alzheimer patients and contribute in the therapeutic effects of the drug.     

Insulin resistance is associated with circulating fibrinogen levels in nondiabetic patients receiving peritoneal dialysis.

BACKGROUND: Insulin resistance (IR) and inflammation are associated with increased risk of cardiovascular disease in the general population. Continuous glucose absorption in peritoneal dialysis (PD) may induce hyperglycemia and hyperinsulinemia. METHODS: We evaluated IR in nondiabetic patients receiving PD, and analyzed the association between IR and systemic inflammation biomarkers by performing a cross-sectional study on ambulatory dialysis. A total of 25 nondiabetic patients receiving PD and 25 healthy individuals, matched for gender, age, and body mass index (BMI), were included. The PD group was composed of 11 men and 14 women, with a mean age of 47 +/- 14 years and mean BMI of 25.5 +/- 4.7 kg/m(2). The control group was composed of 10 men and 15 women, with a mean age of 45 +/- 12 years and BMI of 24.0 +/- 2.8 kg/m(2). RESULTS: IR was evaluated by the homeostasis model assessment method (HOMA-IR). Inflammation was assessed through high-sensitivity C-reactive protein (CRP) and fibrinogen. Body composition and truncal fat were evaluated by dual energy x-ray absorptiometry. HOMA-IR was significantly higher (P < .0001) in subjects receiving PD (4.9, range: 2.3-9.3 mmol/L x muU/mL) compared with healthy subjects (1.2, range: 0.4-4.8 mmol/L x muU/mL). As expected, compared with controls, patients receiving PD had significantly higher levels of insulin (26.5 +/- 7.5 muU/mL vs 6.3 +/- 3.4 muU/mL; P < .0001), CRP (6.3, range: 0.3-61.1 mg/L vs 2.4, range: 0.6-5.9 mg/L; P = .001), and fibrinogen (379 +/- 101 mg/dL vs 268 +/- 66 mg/dL; P < .0001). However, there were no significant differences in body and truncal fat mass between the groups. A significant correlation between HOMA-IR and fibrinogen (Rho = 0.48; P = .01) was observed. However, no correlation was found between HOMA-IR and CRP. Also, no significant correlations were found between HOMA-IR and body fat mass (Rho = 0.11), and between HOMA-IR and truncal fat mass (Rho = 0.19). CONCLUSIONS: Patients receiving PD demonstrate a state of IR that is associated with high circulating levels of fibrinogen. This suggests that hyperfibrinogenemia may be involved in the pathogenesis of IR in this setting.     

Cell origin in experimental repair of cricoid cartilage defects treated with recombinant human bone morphogenetic protein-2

We determined the origin of new cartilage and new bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) at the site of cricoid cartilage defects in rabbits randomly divided into eight groups. The cricoid cartilage was split vertically along the anterior midline and a strip was excised from the anterior part of the cricoid cartilage in all rabbits. The perichondrium from the anterior part of the cricoid cartilage was trimmed off in four groups; two groups treated with rhBMP-2 and two control groups. In four other groups, the anterior perichondrium was detached and used as a flap with two groups treated with rhBMP-2 and two groups serving as controls. The rabbits were killed 1 week or 4 weeks after surgery. The larynges were removed, fixed and sectioned, and the sections were stained for light microscopy using various cytochemical and immunological techniques. New cartilage was only present close to the host perichondrium adherent to cricoid cartilage in rabbits treated with rhBMP-2. New bone was present 4 weeks after surgery, although calcified matrix and alkaline phosphatase activity could be detected at the site of cricoid defects as early as 1 week after surgery. The cell proliferation marker Ki-67 was strongly expressed in granulation tissue and bone marrow, and it was moderately expressed in muscles adjacent to the cricoid cartilage in rhBMP-2-treated specimens. BMP receptors were strongly expressed in cartilage and moderately expressed in adjacent muscles. We conclude that new cartilage originates from the mesenchymal progenitor cells of host perichondrium adherent to cricoid cartilage in rabbits treated with rhBMP-2. New bone may originate from local muscle.     

Influence on the masticatory system in treatment of obstructive sleep apnea and snoring with a mandibular protruding device: A 2-year follow-up

The aim was to identify the incidence and types of possible adverse events in the masticatory system after treatment with a mandibular protruding device (MPD) during a 2-year period in patients with obstructive sleep apnea (OSA) or snoring. The subjects comprised 65 middle-aged patients (44 OSA patients, 21 snorers). A clinical examination and a questionnaire concerning signs and symptoms from the masticatory system were performed before, after 6 months, and after 2 years of MPD use. The frequencies of registered signs from the masticatory system, such as muscle and joint tenderness, palpation, and pain during mandibular movement, decreased significantly between baseline and the 2-year follow-up. There were significant changes in the mandibular range of protrusion (+0.7 mm, P < .001), overjet (-0.5 mm, P < .001), and overbite (-0.6 mm, P < .001) compared with the initial examination. Nine patients developed a lateral open bite during treatment, and 2 of them experienced subjective symptoms related to the altered occlusion but still used the MPD every night. No patient reported pain on opening the mouth wide or during jaw movements. Two reported tiredness on jaw function. The reported frequency of headaches was also significantly reduced (P < .01). The high compliance rate in MPD use showed that the therapy is well tolerated, but there is a risk of minor alterations in the occlusion during MPD treatment.     

Acute nonlymphatic leukemia among deck officers on coastal tankers: a report of two cases

Deck officers on coastal tankers may be exposed to high concentrations of cargo vapors during loading and tank-cleaning operations. Two cases of acute nonlymphatic leukemia are described. Both men had worked as chief officers on coastal tankers transporting benzene and other petroleum products.     

Heart failure: Effects of beta receptor antagonists on left ventricular function in patients with clinical evidence of heart failure after myocardial infarction. A double-blind comparison of metoprolol and xamoterol Echocardiographic results from the Metoprolol and Xamoterol Infarction Study (MEXIS)

Two hundred and ten patients with clinical evidence of heartfailure, developing after an acute myocardial infarction, wererandomized to treatment with the ß₁ antagonist metoprolol50–100mg b.i.d. (n=106) or the ß₁ partial agonistxamoterol 100–200 mg bid. (n=104). Left ventricular systolicand diastolic function were assessed with echocardiography andtransmitral Doppler cardiography before and after 3 and 12 monthsof double-blind treatment. E-point septal separation and percent left ventricular fractional shortening were used as indicesof systolic function. The ratio between peak early and latemitral diastolic flow (E/A ratio) and isovolumic relaxationtime were used as indices of diastolic function. In the xamoterol group, there was a deterioration in E-pointseptal separation (P<0·05). A difference between thetreatment groups was present both at 3 months (E-point septalseparation 11·4 vs 13·0 mm, P<0·0l,fractional short ening 271 vs 252%, P<005) and 12 months(E-point septal separation Ill vs 13·2 mm, P<0·05fractional shortening 26·9 vs 25·0%, P<0·05).E/A ratio increased in the metoprolol group (P<0·05)but not in the xamoterol group. At 3 months there was a significantdifference (0·85 vs 0·67, P<0·005 betweenthe groups but not at 12 months. In comparison with the ß₁-receptor antagonist metoprolol,the ß₁ partial agonist xamoterol impaired left ventricularsystolic function in patients with clinical evidence of heartfailure after an acute myocardial infarction.     

Manganese induced brain lesions inMacaca fascicularis as revealed by positron emission tomography and magnetic resonance imaging

A series of positron emission tomography scans was made on two monkeys during a 16-month period when they received manganese(IV)oxide by subcutaneous injection. The distribution of [¹¹C]-nomifensine uptake, indicating dopamine terminals, was followed in both monkey brains. The brain distributions of [¹¹C]-raclopride, demonstrating D₂ dopamine receptors, and [¹¹C]-l-dopa, as a marker of dopamine turnover, were followed in one monkey each. The monkeys developed signs of poisoning namely unsteady gait and hypoactivity. The [¹¹C]-nomifensine uptake in the striatum was reduced with time and reached a 60% reduction after 16 months exposure. This supports the suggestion that dopaminergic nerve endings degenerate during manganese intoxication. The [¹¹C]-l-dopa decarboxylation was not significantly altered indicating a sparing of [¹¹C]-l-dopa decarboxylation during manganese poisoning. A transient decrease of [¹¹C]-raclopride binding occurred but at the end of the study D₂-receptor binding had returned to starting values. The magnetic resonance imaging (MRI) revealed that the manganese accumulated in the globus pallidus, putamen and caudate nucleus. There were also suggestions of gliosis/edema in the posterior limb of the internal capsule. MRI might be useful to follow manganese intoxication in humans as long as the scan is made within a few months of exposure to manganese, i. e. before a reversal of the manganese accumulation.     

Neurotransmitter release evoked by α-latrotoxin in the smooth muscle of the female pig urethra

Neuronal regulation of smooth muscle tone in the female pig urethra has mainly been studied in vitro using electrical field stimulation (EFS) of nerves. Excitatory control is considered to be exerted by released noradrenaline, whereas inhibitory control is non-adrenergic non-cholinergic (NANC), and mediated by nitric oxide (NO), and an as yet unidentified agent. We investigated the functional and morphological effects of α-latrotoxin (αLTX), a spider neurotoxin believed to cause massive release of vesicle-stored neurotransmitters, on spontaneously developed urethral smooth muscle tone. The effects were compared to those of EFS and high potassium. In the presence of the NO-synthesis inhibitor N^ω-nitro-L-arginine (L-NOARG: 0.3 mM) both αLTX and EFS evoked contractions. After treatment with scopolamine and phentolamine, no contraction was observed, and under these conditions αLTX and EFS induced relaxation. At low frequencies (<12 Hz), the EFS-induced relaxations were rapid, whereas at higher frequencies (>12 Hz), they were biphasic, consisting of a rapid first phase followed by a more long-lasting second phase. L-NOARG abolished the relaxations at low frequencies, as well as the first phase of the biphasic relaxation. The second phase was not affected by treatment with L-NOARG, but 0.1 μM ω-conotoxin GVIA, blocker of N-type voltage-operated calcium- channels (VOCCs), markedly reduced or abolished the response. In the presence of L-NOARG or ω-conotoxin GVIA, the αLTX-induced relaxation was significantly decreased, and the combination of L-NOARG and ω-conotoxin GVIA further reduced or abolished the relaxation. In preparationstreated with tetrodotoxin or scorpion venom, believed to inactivate nerves by acting on sodium channels, αLTX and EFS had no effects. αLTX-induced relaxation was not associated with changes in cyclic GMP or cyclic AMP content. High (80 mM) potassium solution induced a triphasic response of the preparation. A transient relaxation was followed by a restoration of tone, and then by a persistent relaxation. The persistent relaxation was slightly reduced by scorpion venom or L-NOARG, but reduced by 50% by a combination of L-NOARG and ω-conotoxin GVIA. Ultrastructural analysis of the urethral circular smooth muscle layer revealed a moderate amount of nerve profiles supplying the smooth muscle. In control preparations, the nerve profiles contained both small synaptic vesicles and large dense core vesicles. αLTX caused a major loss of both types of vesicle. The present data suggest that αLTX has the ability to release not only adrenergic and cholinergic transmitters, but also NANC mediators of relaxation, including NO, from nerve terminals in the urethra. Received: 13 January 1997 / Accepted: 17 April 1997