Interaction of glycogen synthase of rabbit skeletal muscles with flavin mononucleotide

The effect of flavin mononucleotide (FMN) on the activity of the I- and D-forms of rabbit skeletal muscle glycogen synthase has been studied for the first time. FMN has been shown to inhibit in a noncompetitive fashion the both forms of the enzyme, the D-form being more sensitive to the effect of the inhibitor. It has been shown also that glycogen synthase has three different sites involved in the interaction with inhibitors, namely, and active site, an adenyl nucleotide binding site and a FMN binding site. FMN binding has been shown to occur mostly via the isoalloxasine ring.     

Shelf Life of Fluorescent Treponemal Antibody-Absorption Test Reagents

Properly prepared, standarized, and stored fluorescent treponemal antibody-absorption (FTA-ABS) reagents have been shown to have stabilities equal to other biological reagents. A liquid antigen over 10 years old has been shown to give a satisfactory reaction. Newer preparations have now been shown to be stable for over 5 years, and the tests on each are being continued. The very new liquid antigens which were originally standardized by the FTA-ABS method have shown no decrease in potency over a 20-month period. Stability studies on antigens dried on slides are now in their eighth month, with no apparent loss in potency. The stability of the conjugate is constant when stored frozen at -20 C or lyophilized. When stored as a liquid at 4 C, the stability is governed by the pH and the molarity of the buffer. The standardized and lyophilized sorbent has been shown to be stable for over 1 year.     

Nicotinic receptors in aging and dementia

Activation of neuronal nicotinic acetylcholine receptors (nAChRs) has been shown to maintain cognitive function following aging or the development of dementia. Nicotine and nicotinic agonists have been shown to improve cognitive function in aged or impaired subjects. Smoking has also been shown in some epidemiological studies to be protective against the development of neurodegenerative diseases. This is supported by animal studies that have shown nicotine to be neuroprotective both in vivo and in vitro. Treatment with nicotinic agonists may therefore be useful in both slowing the progression of neurodegenerative illnesses, and improving function in patients with the disease. While increased nicotinic function has been shown to be beneficial, loss of cholinergic markers is often seen in patients with dementia, suggesting that decreased cholinergic function could contribute to both the cognitive deficits, and perhaps the neuronal degeneration, associated with dementia. In this article we will review the literature on each of these areas. We will also present hypotheses that might address the mechanisms underlying the ability of nAChR function to protect against neurodegeneration or improve cognition, two potentially distinct actions of nicotine.     

A clinical trial of IL-15 and IL-21 combination therapy for COVID-19 is warranted

Previous studies of SARS-CoV-2 viral infection suggest that both the humoral and cytotoxic arms of the immune system are weak in patients with severe COVID-19 disease when compared to mild disease. A cytokine storm is also induced in severe disease. IL-15 has been shown to support the cytotoxic arm of the immune response. IL-21 has been shown to support both the cytotoxic and humoral arms of the immune response. In addition, in some settings, Il-21 has been shown to actually decrease IL-6 and TNF-alpha production, reducing the inflammatory proteins involved in the cytokine storm. Furthermore, in other settings, the combination of IL-15 and IL-21 has been shown to be more effective than either interleukin alone in promoting an effective immune response. Therefore, a clinical trial that examines the use of the combination of IL-15 and IL-21 for COVID-19 patients is warranted.     

An Improved Estimator of the Variance of the Regression Estimator

In this paper, the problem of estimation of variance of the general linear regression estimator has been considered. It has been shown that the first order calibration approach is a special case of the class of estimators proposed by Deng and Wu (1987). A second order calibration approach is suggested. Some new estimators are shown to be the special case of the proposed calibration approach. The efficiency of the proposed strategy is shown to improve on the original strategy. An idea to find a non-negative estimate of variance has been suggested.     

Role of BMP family members during kidney development.

Members of the Bone morphogenetic protein (BMP) family have been shown to be important signaling molecules throughout mouse development. Accordingly, many BMPs are also expressed during organogenesis of the metanephric kidney. However, only BMP7 has been shown to be absolutely required for proper formation of the kidney, thus the majority of information known involves this family member. BMP7 is expressed in both the ureteric epithelium and the mesenchyme throughout embryonic development and has been shown to function as a survival factor for the nephrogenic mesenchyme. However, there has been some controversy over the role of BMP7 as an inducing molecule for the metanephric mesenchyme. Recent studies have shown that BMP7 functions as an anti-differentiation factor for this mesenchyme cell population. The function of BMPs in the ureter and in the more differentiated epithelial structures of the nephron is less well understood.     

Induction of immunologic deficiency by benzene and its correction by administration of anabol

Cellular immunity and activity of enzymes of xenobiotic metabolism have been investigated. It has been shown that administration of benzene induces a stable immune deficiency syndrome characterized by a decrease in the quantity if antibody-forming cells, T-killers and T-suppressors. The activity of enzymes (cytochrome P-450 and cytochrome C reductase) was also inhibited. It has been shown that anabol can stimulate the parameters of cellular immunity and enzyme activity. Benzene intoxication was demonstrated to be a model of immune deficiency syndrome similar to the clinical pattern. Anabol was shown to be an effective immunomodulator.     

Cloning and mapping of Saccharomyces cerevisiae photoreactivation gene PHR1.

The yeast Saccharomyces cerevisiae, like most organisms, is able to directly repair pyrimidine dimers by using a photoreactivating enzyme and visible light. Cells carrying the phr1 mutation were shown previously to be unable to photoreactivate dimers, but neither the map position nor the primary gene product of the PHR1 gene has been determined. We have cloned this gene and determined its map position. A plasmid containing a 6.4-kilobase yeast DNA insert has been isolated and shown to restore photoreactivation in a phr1 strain. A 3.1-kilobase subclone has also been shown to complement phr1. The original plasmid was targeted to integrate into chromosomal DNA at a site homologous to the insert by cutting within the insert. Two of these integrants have been mapped on the right arm of chromosome XV; the integrants have been further mapped at ca. 13 centimorgans from prt1. It has also been independently determined that phr1 maps at this location. Thus, we have determined the map position of PHR1 and also have shown that the plasmid contains PHR1 rather than a suppressor of the phr1 mutation.     

Colorectal carcinoma antigens detected by hybridoma antibodies.

Hybridoma cells which secrete colorectal carcinoma-specific antibodies have been produced and used to study the antigenic structure of these tumor cells. Nineteen antibodies have been studied in detail, and 15 of these are colorectal carcinoma specific. Only two antibodies reactive with carcinoembryonic antigen (CEA) have been discovered and five other antibodies that react with distinct epitopes on the cell surface have been defined. Several antigens with distinct molecular characteristics have been shown to exist by use of hybridoma antibodies. Six hybridoma antibodies have been shown to mediate antibody-dependent cell-mediated cytotoxicity (ADCC).     

Mechanisms and control of rapid genomic changes in flax

BACKGROUND AND AIMS: The nuclear DNA of certain varieties of flax (Linum usitatissimum) can vary within a single generation when the plants are grown under specific environmental conditions. This review details the genomic variations that have been identified and associated with this environmental response. CONCLUSIONS: The variation occurs across the whole spectrum of sequence repetition and has been shown to occur in the highly repeated, middle repetitive and low copy number sequences. Although the variation has been shown to be spread throughout the genome it does not occur at random, as similar molecular events have been shown to occur repeatedly. The changes in two labile regions in the nucleus, the ribosomal RNA genes and a site-specific insertion event, have been shown to occur within the period of vegetative growth and over a relatively short period of that growth. The gradual change in total nuclear DNA that has been described would then need to have arisen through an accumulation of changes occurring over the whole, or most of the, period of growth prior to flowering. The polymorphisms that result from these rapidly occurring genomic events have also been observed in many other flax and linseed varieties as well as in the wild progenitors of flax.     

Calmodulin-binding proteins from brain and other tissues.

The calmodulin contents of rabbit brain, lung, kidney and liver, of bovine aorta and uterus, and of chicken gizzard have been determined. 2. The calmodulin in all of these tissues has been shown to be present in the form of very stable complexes with several other proteins. 3. A calmodulin-binding protein of mol.wt. 22 000 has been purified in high yield from bovine brain. It has been shown to interact with calmodulin and rabbit skeletal-muscle troponin C in a Ca2+-dependent manner. 4. The 22 000-mol.wt. protein inhibits the activation of bovine brain phosphodiesterase by calmodulin, but has very little affect on the activation of myosin light-chain kinase. 5. Calmodulin-binding proteins of mol.wts. 140000, 77000 and 61000 have also been partially purified from rabbit brain by affinity chromatography and have been shown to interact in a Ca2+-dependent manner with calmodulin. 6. The apparent molecular weights of the calmodulin-calmodulin-binding protein complexes, determined by gel filtration in the presence of 6M-urea, have been shown to be similar for most of the mammalian tissues examined. 7. By using 125I-labelled calmodulin, similar complexes have been demonstrated in rabbit skeletal muscle, although they are present at much lower concentrations.     

Antimicrobial activity of antiproteinases

Low-molecular-mass neutrophil elastase inhibitors have been shown to be important in the control of lung inflammation. In addition to inhibiting the enzyme neutrophil elastase, these low-molecular-mass compounds (10 kDa) have been shown to have other activities. For example, secretory leucocyte proteinase inhibitor (SLPI) and elastase-specific inhibitor/SKALP (skin-derived antileucoproteinase)/elafin have also been shown to have "defensin"-like antimicrobial activities. Indeed, these inhibitors have antimicrobial properties in vitro against bacteria, fungi and, potentially, HIV. In addition, we have shown, using an adenovirus-mediated gene transfer overexpression strategy, that elafin is also active against Pseudomonas aeruginosa infection in mice in vivo. The mechanism of action is currently under investigation. In addition to these direct or indirect effects on microbes, it has been shown that lipopolysaccharide is able to up-regulate SPLI production in macrophages in vitro, and that the addition of recombinant SLPI to human monocytes or the transfection of macrophages with SPLI can down-regulate pro-inflammatory mediators such as tumour necrosis factor, presumably to limit self-damaging excessive inflammation. Using viral gene transfer vectors, we are currently investigating the potential of these inhibitors in various models of inflammation in vivo.     

Effect of Triton X-100 on accumulation and therapeutic effect of doxorubicin in mice with leukemia P-388 with induced resistance to cytostatic agents]

Using P 388 and P 388/Dx tumour-bearing mice BDF1 it has been studied effect Tritton X-100 on accumulation and therapeutic action of doxorubicin (Dx). It has been shown that LD50 of Tritton X-100 is 153.6 mg/kg and MTD is 80 mg/kg body weight of animals. It has been shown that Tritton X-100 in dose 40 mg/kg body weight increases initial level of Dx in P 388/Dx cells to 215% and doesn't change accumulation of Dx in P 388 cells. It has been shown that Tritton X-100 doesn't influence the therapeutic effect of Dx in P 388 and P 388/Dx tumour-bearing mice.     

Potential usefulness of renal vasodilators in hypertension and renal disease: SK&F 82526

SK&F 82526 and its enantiomers have been shown to increase renal blood flow and decrease renal vascular resistance in the anesthetized dog. The effect of the racemate on lowering systemic blood pressure in the anesthetized dog and the spontaneously hypertensive rat has been shown to be caused by the R-enantiomer with the S-enantiomer being devoid of significant activity on blood pressure. The mechanism by which the R-enantiomer decreases blood pressure is not systemic vasodilatation or prejunctional inhibition of norepinephrine release but appears to result from a unique stimulation of the postjunctional dopamine receptor. Racemic SK&F 82526 also has been shown to increase renal blood flow in an ischemic model of acute renal failure.     

R-isomers of Arg-Gly-Asp (RGD) mimics as potent alphavbeta3 inhibitors

The integrin alpha(v)beta(3), vitronectin receptor, is expressed in a number of cell types and has been shown to mediate adhesion of osteoclasts to bone matrix, vascular smooth muscle cell migration, and angiogenesis. We recently disclosed the discovery of a tripeptide Arg-Gly-Asp (RGD) mimic, which has been shown to be a potent inhibitor of the integrin alpha(v)beta(3) and has excellent anti-angiogenic properties including its suppression of tumor growth in animal models. In other investigations involving RGD mimics, only compounds containing the S-isomers of the beta-amino acids have been shown to be potent. We were surprised to find the potencies of analogs containing enantiomerically pure S-isomers of beta-amino acids which were only marginally better than the corresponding racemic mixtures. We therefore synthesized RGD mimics containing R-isomers of beta-amino acids and found them to be relatively potent inhibitors of alpha(v)beta(3). One of the compounds was examined in tumor models in mice and has been shown to significantly reduce the rate of growth and the size of tumors.     

Protein–solvent interaction

Protein folding and assembly can be manipulated in in vitro systems by co-solvents at high concentrations. A number of co-solvents that enhance protein stability and assembly have been shown to be excluded from the protein surface. Such co-solvent exclusion has been demonstrated by dialysis experiments and shown to be correlated with their effects on protein stability and assembly.     

The effects of thioureylene compounds (goitrogens) on lactoperoxidase activity.

The rates of oxidation of several goitrogens by lactoperoxidase and the rates of inactivation of lactoperoxidase by the same goitrogens have been measured. The influence of iodide on both reactions has also been evaluated. It has been shown by us that iodide acts catalytically in regulating lactoperoxidase activity at pH 8.8. The rate data have been analyzed by a computer program which solves the differential equations for the above mentioned reactions. From this computer analysis we have been able to obtain binding constants of the goitrogens and inactivation rate constants of lactoperoxidase. Iodide was shown to inhibit goitrogenic activity either by increasing the rate of drug oxidation or by reducing the rate of enzyme inactivation, or both, depending on the particular drug. Iodide had little or no effect on the goitrogen-binding constants. We have also shown that the relative rates of enzyme inactivation can be correlated with the potency of the goitrogen as an antithyroid drug.     

Oligonucleotide derivatives in the nucleic acid hybridization analysis. II. Isothermal signal amplification in process of DNA analysis by minisequencing

The isothermal amplification of reporter signal via limited probe extension (minisequencing) upon hybridization of nucleic acids has been studied. The intensity of reporter signal has been shown to increase due to enzymatic labeling of multiple probes upon consecutive hybridization with one DNA template both in homophase and heterophase assays using various kinds of detection signal: radioisotope label, fluorescent label, and enzyme-linked assay. The kinetic scheme of the process has been proposed and kinetic parameters for each step have been determined. The signal intensity has been shown to correlate with physicochemical characteristics of both complexes: probe/DNA and product/DNA. The maximum intensity has been observed at minimal difference between the thermodynamic stability of these complexes, provided the reaction temperature has been adjusted near their melting temperature values; rising or lowering the reaction temperature reduces the amount of reporting product. The signal intensity has been shown to decrease significantly upon hybridization with the DNA template containing single-nucleotide mismatches. Limited probe extension assay is useful not only for detection of DNA template but also for its quantitative characterization.     

EGF regulation of specific endoribonuclease activity of 26S proteasomes from A431 cells: a potential role of proteasomes in control of mRNA stability

For the first time it has been shown that RNase activity is induced under the influence of EGF on epidermoid carcinoma cell line A431. Proteasomes from EGF-treated A431 cells destabilize the 3'-untranslated regions of non-muscle beta actin mRNA, creating a specific cleavage pattern. In addition, these particles have been shown to specifically cleave Alu-containing informational RNA. The enzymatic activity under study has been shown to be dependent on phosphorylation of proteasomal subunits and specifically and selectively regulated by Ca and Mg ions. Proteasome involvement in the coordinated control of stability of specific messenger RNA molecules is suggested. The endoribonuclease activity of 26S proteasomes can constitute a link between EGF signaling pathways and RNA stability.