Stimulation of chloramphenicol acetyltransferase synthesis by cyclic AMP in bacterial cell systems

The effect of cyclic 3,5-adenosine monophosphate (cAMP) on production of the enzyme chloramphenicol acetyltransferase (CAT) by whole bacterial cells was studied in strainsEscherichia coli CSH-2/R222 and WZ-78/R222 (cya₈₅₅). CAT synthesis in strainE. coli WZ-78/R222 was shown to have an intensity only half as great as that of strainE. coli CSH-2/R222. The production of CAT by strainE. coli CSH-2/R222 was increased only very slightly by cAMP, but its effect on the production of this enzyme in strain WZ-78/R222 was appreciable.Research Laboratory of Experimental Immunobiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 10, pp. 65–66, October, 1975.     

Moderate varus/valgus malalignment after total knee arthroplasty has little effect on knee function or muscle strength: 91 patients assessed after 1 year

Background and purpose — Postoperative muscle strength and component alignment are important factors affecting functional results after total knee arthroplasty (TKA). We are not aware of any studies that have investigated the relationship between them. We therefore investigated whether coronal malalignment of the mechanical axis and/or of individual implant components would affect knee muscle strength and function 1 year after TKA surgery.Patients and methods — We included 120 consecutive osteoarthritis (OA) patients admitted for TKA. Preoperative active range of motion (ROM) of the knee, patient age, sex, and BMI were recorded and the Knee Society score (KSS) and knee joint extensor/flexor muscle strength were assessed. At 1-year follow-up, the mechanical and coronal component alignment was measured from a postoperative long standing radiograph, and ROM, KSS, and muscle strength measurements were taken in 91 patients. Functional outcome and muscle strength measurements were compared between normally aligned and malaligned TKA groups.Results — 29 of 91 TKAs were malaligned, i.e. they deviated more than 3° from the neutral mechanical axis. 18 femoral components and 15 tibial components were malaligned. Before surgery, the malaligned and normally aligned groups were similar regarding sex distribution, BMI, ROM, KSS, and muscle strength. At the 1-year follow-up, the differences between the groups regarding knee joint function and muscle strength were small, not statistically significant, and barely clinically relevant.Interpretation — Moderate varus/valgus malalignment of the mechanical axis or of individual components has no relevant clinical effect on function or muscle strength 1 year after TKA surgery.Failure to restore limb alignment in total knee arthroplasty (TKA) increases the risk of revision (Jeffery et al. 1991, Ritter et al. 1994 and 2011, Berend et al. 2004), but the effect of accurate postoperative alignment on TKA function is controversial (Lotke and Ecker 1977, Choong et al. 2009, Fang et al. 2009, Longstaff et al. 2009, Huang et al. 2012).Huang et al. (2012) reported that TKAs with a coronal alignment within 3° from the neutral axis had better function and quality of life at 5-year follow-up than TKAs that deviated more than 3° from neutral alignment. Other studies comparing computer-assisted TKA with conventional TKA surgery have not been able to correlate malalignment with inferior functional outcomes (Spencer et al. 2007, Kamat et al. 2009, Kim et al. 2009, Burnett and Barrack 2013).Patients with greater preoperative muscle strength have been reported to have faster recovery and better functional outcome after TKA (Mizner et al. 2005, Yoshida et al. 2008). However, full recovery of muscle strength after TKA is uncommon (Berth et al. 2002, Valtonen et al. 2009, Maffiuletti et al. 2010, Vahtrik et al. 2012).It is plausible that failure to restore the mechanical axis restoration results in inferior muscle function. Sogabe et al. (2009) found different cross-sectional areas in the quadriceps muscles with different knee alignments. They suggested that knees with varus or valgus deformation should have poorer muscle function compared to normally aligned knees. However, we have not been able find any studies investigating muscle strength after TKA in relation to component alignment and mechanical axis restoration.We investigated whether coronal malalignment of the mechanical axis and/or of individual implant components would affect knee muscle strength and function 1 year after TKA surgery.     

The Rheometric Analysis of the Polymer Modifier’s Properties in the Environment of Hydrated Cement

This paper investigates the effect of polymer modifiers (re-dispersible powder, multifunctional additives, methylhydroxyethylcellulose) on the rheological behavior of emulsions, saturated of calcium hydrosilicates to simulate a hydrating cement structure. The subjects of the study were modified emulsions which had varied concentrations of each additive and they were examined comparatively to a base emulsion. Tests were performed with a CR-rheometer (“Himpribor-1”, Tula, Russia) applying the Searle measuring principle at various shear rates to characterize viscosity properties. The performance of modified mixtures within the operating period was analyzed by using two parameters—effective viscosity (η) and the proportion of structural failure (|m|). The test results showed that the most important factor influencing rheological characteristics is the addition of methylhydroxyethylcellulose additive—the higher additive amount in the emulsion, the higher the viscosity. Furthermore it was noted in the work that adding olefin sulfonate sodium salt causes reduced viscosities as well as lower shear moduli. If ethylhydroxyethylcellulose and ethylene vinyl acetate additives are used in the same mixture together, the rate of structural failure |m| can be relatively similar and low regardless of whether the mixture has large or small viscosity values.     

Degeneration of mammalian PNS and CNS axons is accelerated by incubation with protein synthesis inhibitors

Protein synthesis inhibitors (PSIs) increase the rate of degeneration, as measured by compound action potential (CAP) conduction, in segments of rat PNS and CNS axons. Sciatic axonal segments maintained in vitro in Krebs at 37-38 degrees C generate CAPs for 24 h compared to 8 h for axons exposed to Krebs containing two PSIs, 100 microM anisomycin and/or 35 microM cycloheximide. Spinal axonal segments at 37-38 degrees C generate CAPs for 3 h compared to 2 h for axons exposed to Krebs containing PSIs. While cooling (6-9 degrees C) slows degeneration rate, cooled sciatic axons exposed to PSIs exhibit lower peak CAPs compared to cooled control segments (P<0.005).     

The negative syndrome as a dimension: factor analyses of PANSS in major depressive disorder and organic brain disease compared with negative syndrome structures found in the schizophrenia literature.

OBJECTIVE: To explore the concept of the negative syndrome as a dimensional entity that exists in multiple primary diagnoses, and to compare the negative syndrome in nonschizophrenic disorders and schizophrenia. BACKGROUND: Although initially considered specific to schizophrenia, the negative syndrome has subsequently been described in major depression, stroke, and dementia. METHOD: We performed an exploratory factor analysis on Positive and Negative Symptom Scale scores of 82 subjects with major depressive disorder and 76 subjects with organic brain disease (dementia or stroke). RESULTS: The examination of the resultant symptom clusters revealed that the structure of the negative syndrome in major depressive disorder and organic brain disease closely corresponded to that in schizophrenia literature. CONCLUSIONS: The negative syndrome may be a nosologic entity, which remains fairly consistent across psychotic and nonpsychotic diagnostic categories. Confirmatory studies are merited to determine the degree and strength of the similarity in structure of the negative syndrome in psychotic, affective, and cognitive illness.     

Lanthanum and Manganese Co-Doping Effects on Structural,Morphological, and Magnetic Properties of Sol-Gel Derived BiFeO3

In this work, lanthanum and manganese co-substitution effects on different properties of bismuth ferrite solid solutions Bi_1-xLa_xFe_0.85Mn_0.15O₃ (x from 0 to 1) prepared by a sol-gel synthetic approach have been investigated. It was observed that the structural, morphological, and magnetic properties of obtained specimens are influenced by the amount of introduced La³⁺ ions. Surprisingly, only the compound with a composition of BiFe_0.85Mn_0.15O₃ was not monophasic, and the presence of neighboring phases was determined from X-ray diffraction analysis and Mössbauer measurements. Structural transitions from orthorhombic to cubic and back to orthorhombic were also observed depending on the La³⁺ amount. Antiferromagnetic behaviour was observed for all of the samples, with the highest magnetisation values for Bi_0.5La_0.5Fe_0.85Mn_0.15O₃. Additionally, structural attributes and morphological features were evaluated by Raman spectroscopy and scanning electron microscopy (SEM), respectively.     

Clinical and genetic heterogeneity of erythrokeratoderma variabilis

The skin disease erythrokeratoderma variabilis (EKV) has been shown to be associated with mutations in GJB3 and GJB4 encoding connexin (Cx)31 and Cx30.3, respectively. Gap junctions composed of Cx proteins are intracellular channels providing a mechanism of synchronized cellular response facilitating metabolic and electronic functions of the cell. In the skin, Cx31 and Cx30.3 are expressed in the stratum granulosum of the epidermis with a suggested role in late keratinocyte differentiation. Molecular investigations of GJB3 and GJB4 were performed in five pedigrees and three sporadic cases of EKV. Mutational analyzes revealed disease-associated Cx31 or Cx30.3 mutations in only three probands of which two were novel mutations and one was a recurrent mutation. These genetic studies further demonstrate the heterogeneous nature of the erythrokeratodermas as not all individuals that were clinically diagnosed with EKV harbor Cx31 or Cx30.3 mutations.