Deleterious effects of the prone position in the full-term infant throughout the first year of life

Summary Seventy-one first-born infants who had been nursed in prone position since birth, were referred for motor assessment at 3 months, 5 months and 9 months. All infants were administered the same checklist of motor items, based on the Amiel-Tison Infant Neurological Evaluation and on the Brunet-Lézine Developmental Psychomotor Scale. Abnormalities in muscular shortening and delay in motor skills were found. These findings are critical as regards environmental influences on postural development, continuities in motor development and issues of early primary prevention. Early identification and follow-up programmes, including frequent changes in posture, are suggested in order to avoid abnormalities of motor behaviour and subsequently in postural patterns.     

Acute, Distribution, and Subchronic Toxicological Studies of Succinate Tartrates

The estimated single-dose oral toxicity (50% lethality) of succinatetartrates (ST) was 2–3 g/kg in rats. ST produced minimalto moderate dermal irritation but no evidence of systemic toxicityin a standard acute percutaneous toxicity test in rabbits. STwas not an eye irritant in a standard rabbit low-volume eyeirritation test ST was not genotoxic in a series of six genotoxicitytests. A 14-day oral gavage study in rats at a dose range of0.05–1.0 g ST/kg/day produced only gastric irritation.The no-observed-effect level (NOEL) for gastric irritation was0.1 g/kg for males and 0.05 g/kg for females. A 28-day percutaneoustoxicity study in rabbits produced minimal to moderate dermalirritation and no adverse systemic effects at a high dose of450 mg ST/kg/day. Single-dose absorption, distribution, andelimination (ADE) studies in male rats showed that 10–15%of an oral dose and 1–3% of a dermal dose were absorbed.Approximately 98% of the orally administered ST was eliminatedas ¹⁴C in urine, feces, or expired CO₂ after 72 hr. Approximately80% of the dermally absorbed ¹⁴C dose was eliminated in urine,feces, or expired CO₂ after 72 hr. In conclusion, no adverseeffects were noted in acute toxicity, genotoxicity, or subchronictoxicity studies conducted with ST.     

Feasibility assessment of shear wave elastography to lumbar back muscles

Low back pain is often associated with tensional changes in the paraspinal muscles detected by palpatory procedures. Shear wave elastography (SWE), recently introduced, allows the stiffness of muscles to be assessed noninvasively. The aim of this work was to study the feasibility of using SWE on the three main lumbar back muscles (multifidus, longissimus, and iliocostalis) in vivo after analyzing their muscular architecture ex vivo. We determined the orientation of fibers in the multifidus, longissimus, and iliocotalis muscles in seven fresh cadavers using gross anatomy and B‐Mode ultrasound imaging. We then quantified the stiffness of these three muscles at the L3 level ex vivo and in 16 healthy young adults. Little pennation was observed in the longissimus and iliocostalis, in which the direction of fibers was almost parallel to the line of spinous processes. The multifidus appeared as a multiceps and multipennate muscle. Given the random layering of millimetric fascicles, tendons, and fatty spaces, the multifidus had multiple fiber orientations. Muscular fascicles and fibers were oriented from 9° to 22° to the line of spinous processes. The shear moduli related to stiffness were 6.9 ± 2.7 kPa for the longissimus, 4.9 ± 1.4 kPa for the iliocostalis, and 5.4 ± 1.6 kPa for the multifidus. SWE is a feasible method for quantifying the stiffness of the lumbar back muscles. Clin. Anat. 30:774–780, 2017. © 2017Wiley Periodicals, Inc.     

A simple method for measuring DNA synthesis in epidermis and sebaceous glands and its application in chalone assays

Liquid scintillation counting and autoradiography were used to measure DNA synthesis (3H-TdR uptake and incorporation) by the epidermis and the sebaceous glands in mouse pinna skin. Using this approach it has been possible to show that a chalone-like inhibitor of DNA synthesis acts rapidly to restrict the flow of epidermal G1 cells into S-phase. The point of action within the cell cycle is probably at the G1-S phase 'boundary'. The technique described is sufficiently sensitive to be used for measuring small alterations in DNA synthesis in short-term experiments and for long-term experiments in which the size of the progenitor cell population is altered by systemic or topical administration of compounds influencing DNA synthesis.     

Radiofrequency Catheter Ablation of Atrial Flutter Induces the Release of Platelet and Leukocyte-Derived Procoagulant Microparticles and a Prothrombotic State

Background: To assess the extent of endothelium, platelet, and leukocyte damage and coagulation activation induced by radiofrequency catheter ablation (RF) of atrial flutter. In the vasculature, procoagulant microparticles (MPs) are reliable markers of vascular damage. They provide an additional phospholipidic surface, enabling the assembly of the enzyme complexes of blood coagulation and consequent thrombin generation.
Methods: MPs were measured in the venous blood of 33 patients with isthmus-dependent atrial flutter undergoing RF before (RF₀), immediately after (RF₁), and at day 1 (RF₂) thereafter. Concentrations of PAI-1, vWF, and D-dimers were simultaneously determined. MPs procoagulant activities were determined using a functional prothrombinase assay. RF induces an early rise of platelet-derived MPs (platelet), vWF Ag, and D-dimers levels, which is concomitant with the decrease of PAI-1 concentrations. Conversely, no significant changes in endothelial-derived MPs could be evidenced. At RF₂, sustained elevation of leukocytes-derived MPs, vWF, and D-dimers testified to an ongoing prothrombotic status.
Conclusion: RF ablation of common flutter induces a prothrombotic state and the release of platelet and leukocyte-derived procoagulant microparticles. Whereas this activation of blood coagulation could be viewed as clinically marginal in right-sided procedures, its relevance in left-sided procedures should be established.     

Didemnin B Conformation and dynamics of an antitumour and antiviral depsipeptide studied in solution by 1H and 13C. n.m.r. spectroscopy

The solution conformation of didemnin B, the most potent member of a family of depsipeptides that shows antitumour, antiviral, and immunosuppressive activity, has been studied in chloroform solution using n.m.r. spectroscopy. ¹H and ¹³C spectra have been assigned from analysis of a number of two-dimensional homonuclear and heteronuclear chemical shift correlation experiments which confirm the recently corrected primary structure of the molecule. The conformation of the peptide has been deduced from measurements of the temperature dependence of the NH chemical shifts, analysis of coupling constant data and primarily through NOE effects observed in the rotating frame. Interproton distance bounds determined from a quantitative analysis of the ROE data provide 41 constraints from which a family of closely related structures were calculated using distance geometry algorithms. A type II β-turn involving residues Thr⁶, Leu⁷, and Pro⁸ is well represented in the computed conformers as is a hydrogen bonding interaction between the NH of Leu³ and the carbonyl oxygen of Thr⁶. This latter interaction causes the linear portion of the structure to fold back over the depsipeptide ring, imparting to it a degree of structural stability as well as giving the molecule a somewhat globular character. Only one transannular hydrogen bond, between 1st¹ NH and Leu³ carbonyl, stabilizes the conformation of the depsipeptide, which has an irregular non-planar configuration. The small temperature coefficients (< 2.0 × 10^?3ppm/°C) for the NHs of 1st¹ and Leu³ are consistent with their involvement in these hydrogen bonding interactions. We find that many of the structural features observed in the crystalline form of didemnin B are conserved in solution. Analysis of the ¹³C spin-lattice relaxation rates of the protonated carbons reveals small variations in effective correlation times at specific sites in the molecule. The data suggests that the peptide segment encompassing residues Leu³through to Thr⁶ is in a more motionally restricted part of the structure.     

Catheter-induced A-V Nodal Block Occurring during Electrophysiologic Study

We describe a patienl who underwent electrophysiologic study for evaluation of recurrent syncope. No abnormalities were found but high-grade A-V block proximal to the A-V bundle depolarization developed abruptly as the coronary sinus electrode catheter was being withdrawn. The A-V block disappeared gradually over a 12-hour period, progressing to type I second-degree A-V block, and then to first-degree A-V block (due to prolonged A-V nodal conduction), prior to resuming normal conduction. We postulate that A-V block was induced by direct contact between the electrode catheter and the A-V node or very proximal His bundle. Catheter-induced A-V block at this site has been described only rarely, possibly because of the relatively protected location and the configuration of the A-V node.