Influence of selective phosphodiesterase inhibitors on human neutrophil functions and levels of cAMP and Cai

Summary Chromatographic analysis of 3,5-cyclic nucleotide phosphodiesterase (PDE) isoenzymes in the cytosol of human neutrophils shows the predominant presence of PDE IV (cAMP specific) and PDE V (cGMP specific). PDE IV is characterized by (1) cAMP selectivity, (2) a K_M for cAMP of 1.2 M and (3) a typical rank order of IC ₅₀-values for PDE inhibitors: 0.13, 0.17, 47 and 9.5 M for PDE IV selective rolipram, PDE III/IV selective zardaverine, PDE III selective motapizone and unselective 3-isobutyl-l-methylxanthine (IBMX), respectively. Functions of polymorphonuclear leukocytes (PMN) such as N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated superoxide release and fMLP/thimerosal elicited leukotriene (LT) biosynthesis are inhibited by these PDE inhibitors with the same rank order and even lower IC₅₀-values. Measurements of changes in cytosolic Ca_i in Fura-2 loaded PMN demonstrate a transient Ca_i increase after stimulation with 0.1 M fMLP and an additional sustained elevation of Ca_i levels in the presence of thimerosal. PDE inhibitors suppress this sustained phase of Ca_i release with the same rank order of IC₅₀-values as LT biosynthesis. The correlation between fMLP/thimerosal-induced LT biosynthesis and Ca_i levels reveal a Ca_i threshold of 150 nM for arachidonic acid metabolism. cAMP levels in PMN were elevated by PDE inhibitors alone by less than 2-fold. In the presence of fMLP however, cAMP was increased up to 10-fold and the efficacy of PDE inhibitors to increase cAMP paralleled their potency to inhibit PDE IV. It is concluded that (1) suppression of PMN functions is achieved by PDE IV inhibition, (2) necessary cAMP elevations are within 50% increase, (3) superoxide release was affected by cAMP/protein kinase A (PKA) directly whereas (4) for inhibition of LT biosynthesis a cAMP related reduction of Ca-influx is involved. Send offprint requests to Ch. Schudt at the above address     

Evaluation of irradiation techniques in breast carcinoma using dose-volume histograms. Comparison of the heart and lung exposure

For irradiation of the internal mammary lymph nodes (IMN), together with irradiation of the breast the commonly used treatment techniques are of three types: 1. two tangential opposed fields, 2. three field plans with a separate "straight on" IMN-field, or 3. with a separate "angled" IMN-field. To determine lung and heart volumes and doses for these techniques, dose-volume-histograms in 30 patients were analyzed. The optimum dose distribution was achieved with the "angled" field technique and an appropriate combination of electrons and 60Co gamma radiation for the IMN-field. (The beam mixture used was 40% 60Co beam and 60% electron beam.) The least possible dose to the lung was obtained with the "straight-on" field technique and the least possible dose to the heart with the separate "angled" IMN-field technique.     

Low vitamin D status is associated with low cord blood levels of the immunosuppressive cytokine interleukin-10

The cytokine interleukin-10 (IL-10) plays a pivotal regulatory role in tolerizing exogenous antigens. Experimental data indicate that low cellular availability of the vitamin D hormone 1,25-dihydroxyvitamin D [1,25(OH)2D] results in a down-regulation of IL-10 concentrations. The tissue production of an adequate amount of 1,25(OH)2D depends on a high circulating 25-hydroxyvitamin D (25-OHD) level. The present study was thus aimed at evaluating the associations between season of birth, vitamin D status, and the allergy risk markers IL-10 and total immunoglobulin (IgE) in newborns. Cord blood was obtained from 49 infants born during the summer half year (mid-April to mid-October, geographic latitude 51 degrees N) and from 47 infants born during the winter half year (mid-October to mid-April, geographic latitude of 51 degrees N). Serum levels of 25-OHD were 99% higher, and IL-10 levels were 43% higher in the summer half year compared with the winter half year (p < 0.001 and p = 0.018). Moreover, the ratio of IL-10 to total IgE was 124% higher in the summer half year compared with the winter half year (p = 0.039). Serum levels of 25-OHD were correlated with IL-10 levels (r = +0.22; p < 0.05). Mothers' age, gestational ages, birth weights and serum 1,25(OH)2D levels did not differ between study groups. We conclude that the low vitamin D status of infants born in winter may at least in part adversely affect biomarkers of allergy risk.     

Chinikomycins A and B: isolation, structure elucidation, and biological activity of novel antibiotics from a marine Streptomyces sp. isolate M045

In our screening of marine Streptomycetes for bioactive principles, two novel antitumor antibiotics designated as chinikomycins A (2a) and B (2b) were isolated together with manumycin A (1), and their structures were elucidated by a detailed interpretation of their spectra. Chinikomycins A (2a) and B (2b) are chlorine-containing aromatized manumycin derivatives of the type 64-pABA-2 with an unusual para orientation of the side chains. They exhibited antitumor activity against different human cancer cell lines, but were inactive in antiviral, antimicrobial, and phytotoxicity tests.     

Sulfemodin 8-O-beta-D-glucoside,a new sulfated anthraquinone glycoside,and antioxidant phenolic compounds from Rheum emodi

A sulfated emodin glucoside, emodin 8-O-beta-D-glucopyranosyl-6-O-sulfate (1), was isolated from the roots of Rheum emodi in an investigation of the active constituents of this Nepalese medicinal plant, and its structure was determined by spectroscopic and chemical methods. Additionally, two rare auronols, carpusin (2) and maesopsin (3), besides other anthraquinones and phenolics, were isolated and identified. Compounds 2 and 3 showed significant antioxidant activity in the DPPH assay, while chrysophanol, physcion, and emodin and their 8-O-glucosides were found to be inactive.     

A case report of prolonged COVID‐19‐positive RT‐PCR for five months

The COVID‐19 gold standard assessment tool remained the RT‐PCR of upper respiratory tract specimen extracted by the nasopharyngeal swab. A positive result would decrease through a three‐week course and eventually be undetectable. The maximum duration of viral shedding is 83 days. Besides, COVID‐19 RT‐PCR remained positive for 74 days in a patient suffering from lymphoma. In this study, we have presented a 56‐year‐old male patient, a known case of lymphoma since 2015, who experienced many episodes of chemotherapy with a five‐month positive RT‐PCR COVID‐19 laboratory test and finally was intubated and then died of opportunistic pulmonary infections. COVID‐19 patients with concurrent lymphoma failed to remove the virus thoroughly, despite providing appropriate treatment regimens.     

Targeted Mutations in the Fusion Peptide Region of La Crosse Virus Attenuate Neuroinvasion and Confer Protection against Encephalitis

La Crosse virus (LACV) is a major cause of pediatric encephalitis and aseptic meningitis in the Midwestern, Mid-Atlantic, and Southern United States, where it is an emerging pathogen. The LACV Gc glycoprotein plays a critical role in the neuropathogenesis of LACV encephalitis as the putative virus attachment protein. Previously, we identified and experimentally confirmed the location of the LACV fusion peptide within Gc and generated a panel of recombinant LACVs (rLACVs) containing mutations in the fusion peptide as well as the wild-type sequence. These rLACVs retained their ability to cause neuronal death in a primary embryonic rat neuronal culture system, despite decreased replication and fusion phenotypes. To test the role of the fusion peptide in vivo, we tested rLACVs in an age-dependent murine model of LACV encephalitis. When inoculated directly into the CNS of young adult mice (P28), the rLACV fusion peptide mutants were as neurovirulent as the rLACV engineered with a wild-type sequence, confirming the results obtained in tissue culture. In contrast, the fusion peptide mutant rLACVs were less neuroinvasive when suckling (P3) or weanling (P21) mice were inoculated peripherally, demonstrating that the LACV fusion peptide is a determinant of neuroinvasion, but not of neurovirulence. In a challenge experiment, we found that peripheral challenge of weanling (P21) mice with fusion peptide mutant rLACVs protected from a subsequent WT-LACV challenge, suggesting that mutations in the fusion peptide are an attractive target for generating live-attenuated virus vaccines. Importantly, the high degree of conservation of the fusion peptide amongst the Bunyavirales and, structurally, other arboviruses suggests that these findings are broadly applicable to viruses that use a class II fusion mechanism and cause neurologic disease.     

Cytotoxic bastadin 24 from the Australian sponge Ianthella quadrangulata

A new cytotoxic bastadin, bastadin 24 ( 1), and the previously reported bastadins 4, 5, 6, 7, 12, 13, and 21 ( 2- 8) were isolated from a polar extract of the Australian marine sponge Ianthella quadrangulata. The planar structure of bastadin 24 ( 1) was elucidated as the 25-hydroxy derivative of bastadin 6 ( 4) by employing spectroscopic techniques (NMR, MS, UV, and IR). All isolated bastadins were evaluated for their cytotoxicity toward a panel of 36 human tumor cell lines and were found to be moderately cytotoxic. Bastadin 24 ( 1) exhibited selective cytotoxic activity toward five of the 36 investigated tumor cell lines. Bastadins 7 ( 5) and 12 ( 6) significantly inhibited the serum + hEGF-induced (human epithelial growth factor) tubular formation of human umbilical vein endothelial cells (HUVEC) at a concentration of 1 mug/mL.