Pinocytic uptake and intracellular degradation of N-(2-hydroxypropyl)methacrylamide copolymers a potential drug delivery system

Synthetic ¹²⁵I-labelled N-(2-hydroxypropyl)methacrylamide copolymers containing four different, potentially degradable peptidyl side chains were incubated with rat visceral yolk sacs cultured in vitro. All copolymers were captured by fluid-phase pinocytosis and three of the side chains were susceptible to lysosomal hydrolysis, resulting in release of [¹²⁵I]iodotyrosine back into the culture medium. Uptake and degradation was completely inhibited by 2,4-dinitrophenol. The thiol-proteinase inhibitor leupeptin did not affect the rate of pinocytosis, but caused different degrees of inhibition of hydrolysis depending on side chain composition.     

Are there turbidites in the Silurian/Devonian boundary stratotype? (Klonk near Suchomasty,Barrandian, Czechoslovakia)

Summary A discussion arose in 1977 regarding the nature of the Silurian/Devonian boundary bed at Klonk, and the beds below and above it. Present revision of the stratotype sequence found that most clayey limestones display a multiple and composed rhythmic arrangement of laminae. Deposition of pelagic particles, effects of traction bottom currents, and turbidite inputs are distinguishable, however, the latter are rare. Semilithified surfaces and hardgrounds were found. The boundary bed No. 20 consists of several laminated rhythms. The Devonian base, marked by first occurrences ofMonograptus uniformis corresponds to a semilithified surface, a break in deposition for several tens to hundreds of years, and a change in direction of bottom currents. A moderately rippled set at the Devonian base is only about 1 cm thick and passes again into the horizontal laminated rhythms. The deposition of the boundary bed lasted about 1.2 to 2.0 Ka. It cannot be explained as a turbidite.     

Prophylactic veno-arterial extracorporeal membrane oxygenation in patients undergoing high-risk percutaneous coronary intervention

Netherlands Heart Journal - Complex high-risk percutaneous coronary intervention (PCI) is challenging and frequently accompanied by haemodynamic instability. Veno-arterial extracorporeal membrane...     

Diagnosis of takotsubo cardiomyopathy is increasing over time in patients presenting as ST-elevation myocardial infarction

Background

Takotsubo cardiomyopathy often presents with the clinical signs of ST-elevation myocardial infarction (STEMI). The increase in scientific publications addressing this relatively rare condition may result in higher awareness and diagnosis of takotsubo cardiomyopathy.

Aim

To assess the observed prevalence per year of takotsubo cardiomyopathy in a large registry of patients with STEMI, during a 12-year inclusion period.

Method

All patients presenting with STEMI at a large regional cardiology clinic were entered into a database (n = 8,413, mean age 63 ± 13 years). Takotsubo cardiomyopathy was diagnosed in 42 patients (0.5?%). Years of evaluation were defined as ‘early years’ (January 2002 to December 2007; n = 4350) and ‘later years’ (January 2008 to December 2013). Multivariable analyses were performed to adjust for differences in demographical and clinical variables.

Results

In later years, the age of STEMI patients was slightly higher (64 ± 13 vs. 63 ± 13 years, p < 0.001), with more patients with clinical symptoms of shock (10 vs. 7?%, p < 0.001) or a history of percutaneous coronary intervention or hypertension (10 vs. 8?%, p = 0.001 and 37 vs. 34?%, p < 0.001). Smoking and a positive family history were less often observed during later years (39 vs. 46?%, p < 0.001 and 37 vs. 42?% p < 0.001). Patients with takotsubo cardiomyopathy were more often female (81 vs. 27?%, p = 0.001). Takotsubo cardiomyopathy was more often diagnosed in the later period (0.7 vs. 0.3?%, OR 2.4, 95?% CI 1.2–4.6, p = 0.009). The higher prevalence of takotsubo cardiomyopathy in recent years remained significant after adjustment for differences in patient characteristics (OR 2.1, 95?% CI 1.1–4.3).

Conclusion

Takotsubo cardiomyopathy is currently more often diagnosed in patients with STEMI compared with in earlier years. This is probably due to the increased scientific and clinical awareness among doctors, but the prevalence is still low.

     

Properties of pyranose dehydrogenase purified from the litter-degrading fungus Agaricus xanthoderma

We purified an extracellular pyranose dehydrogenase (PDH) from the basidiomycete fungus Agaricus xanthoderma using ammonium sulfate fractionation and ion-exchange and hydrophobic interaction chromatography. The native enzyme is a monomeric glycoprotein (5% carbohydrate) containing a covalently bound FAD as its prosthetic group. The PDH polypeptide consists of 575 amino acids and has a molecular mass of 65 400 Da as determined by MALDI MS. On the basis of the primary structure of the mature protein, PDH is a member of the glucose-methanol-choline oxidoreductase family. We constructed a homology model of PDH using the 3D structure of glucose oxidase from Aspergillus niger as a template. This model suggests a novel type of bi-covalent flavinylation in PDH, 9-S-cysteinyl, 8-alpha-N3-histidyl FAD. The enzyme exhibits a broad sugar substrate tolerance, oxidizing structurally different aldopyranoses including monosaccharides and oligosaccharides as well as glycosides. Its preferred electron donor substrates are D-glucose, D-galactose, L-arabinose, and D-xylose. As shown by in situ NMR analysis, D-glucose and D-galactose are both oxidized at positions C2 and C3, yielding the corresponding didehydroaldoses (diketoaldoses) as the final reaction products. PDH shows no detectable activity with oxygen, and its reactivity towards electron acceptors is rather limited, reducing various substituted benzoquinones and complexed metal ions. The azino-bis-(3-ethylbenzthiazolin-6-sulfonic acid) cation radical and the ferricenium ion are the best electron acceptors, as judged by the catalytic efficiencies (k(cat)/K(m)). The enzyme may play a role in lignocellulose degradation.     

Antisense oligonucleotides delivered to the lysosome escape and actively inhibit the hepatitis B virus

The subcellular fate and activity in inhibiting the hepatitis B virus of free and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-phosphorothioate oligonucleotides were studied. Their internalization and subcellular fate were monitored with confocal microscopy. A fraction of the internalized free oligonucleotides escaped into the cytoplasm and nucleus of Hep G2 cells but were not active antiviral agents. Covalently attaching the oligonucleotides to the HPMA copolymers via nondegradable dipeptide GG spacers resulted in sequestering the oligonucleotides in vesicles after internalization. Conjugation of the oligonucleotides to an HPMA copolymer via a lysosomally cleavable tetrapeptide GFLG spacer resulted in release of the oligonucleotide in the lysosome and subsequent translocation into the cytoplasm and nucleus of the cells. The HPMA copolymer-oligonucleotide conjugate possessed antiviral activity, indicating that phosphorothioate oligonucleotides released from the carrier in the lysosome were able to escape into the cytoplasm and nucleus and remain active. The Hep G2 cells appeared to actively internalize the phosphorothioate oligonucleotides as oligonucleotide-HPMA copolymer conjugates were internalized to a greater extent than unconjugated polymers.     

Haemangiomas of the orbit

The authors describe their experience with systemic therapy of cavernous haemangiomas making use of interferon alpha. They have successfully used the method in treating two female patients with cavernous haemangiomas in the orbit. In the first patient, the IFN therapy was followed by surgical removal of the tumour. In the second patient, surgical operation was not suitable. After the IFN therapy, the patient's state improved both subjectively and objectively. Decreased level of bFGF in urine prove to be the criterion for successful treatment by IFN. The authors also stress the risk of complications in sucklings. When choosing the method of treatment, they emphasize the necessity of interdisciplinary cooperation.