Predefined vs data-guided training prescription based on autonomic nervous system variation: A systematic review

Monitoring variations in the functioning of the autonomic nervous system may help personalize training of runners and provide more pronounced physiological adaptations and performance improvements. We systematically reviewed the scientific literature comparing physiological adaptations and/or improvements in performance following training based on responses of the autonomic nervous system (ie, changes in heart rate variability) and predefined training. PubMed, SPORTDiscus, and Web of Science were searched systematically in July 2019. Keywords related to endurance, running, autonomic nervous system, and training. Studies were included if they (a) involved interventions consisting predominantly of running training; (b) lasted at least 3 weeks; (c) reported pre- and post-intervention assessment of running performance and/or physiological parameters; (d) included an experimental group performing training adjusted continuously on the basis of alterations in HRV and a control group; and (e) involved healthy runners. Five studies involving six interventions and 166 participants fulfilled our inclusion criteria. Four HRV-based interventions reduced the amount of moderate- and/or high-intensity training significantly. In five interventions, improvements in performance parameters (3000 m, 5000 m, Loadmax, Tlim) were more pronounced following HRV-based training. Peak oxygen uptake () and submaximal running parameters (eg, LT1, LT2) improved following both HRV-based and predefined training, with no clear difference in the extent of improvement in . Submaximal running parameters tended to improve more following HRV-based training. Research findings to date have been limited and inconsistent. Both HRV-based and predefined training improve running performance and certain submaximal physiological adaptations, with effects of the former training tending to be greater.     

Differential role of the vagus in diurnal gene expression rhythms in the small intestine

The objective of this study was to examine the function of vagal innervation in maintaining diurnal rhythmicity in the expression of intestinal absorptive genes. Rats underwent truncal vagotomy and were maintained for 7 days on nighttime scheduled feeding (12-h light/12-h dark cycle). Vagotomized rats (V; n = 9) were pair-fed with sham-operated controls (S; n = 4). Unoperated normal rats (N; n = 6) were also included as controls. Half the rats were killed 3 h after lights on (ZT3; Zeitgeber Time, with lights-on considered ZT0) and the other half at ZT9, the time interval over which we have previously shown that sucrase and sugar transporter expression exhibits a significant anticipatory increase. RNA and protein extracted from mucosa of proximal jejunums were subjected to Northern and Western blot analyses to assess the increase in gene expression. Sham operation did not alter the normal diurnal rhythmicity of intestinal gene expression. Control rats (S plus N) exhibited the expected increase in RNA levels at ZT9 versus ZT3 for SGLT1 (4.5-fold), GLUT2 (5.3-fold), GLUT5 (4.1-fold), and sucrase (2.9-fold; P > 0.001 in all cases). In contrast, the induction in V rats was markedly blunted for GLUT2 (1.3-fold) and sucrase (1.5-fold) but not for SGLT1 (5.0-fold) or GLUT5 (4.2-fold). The mRNA levels for GLUT2 and sucrase at ZT9 were significantly lower in V rats versus controls (P < 0.001). GLUT2 and SGLT1 protein levels exhibited a parallel pattern: SGLT1 induction was 4.3-fold in control rats (P < 0.01) and 3.8-fold in V rats (P <0.01), whereas GLUT2 induction was 3.3-fold in control rats (P < 0.01) but only 1.4-fold in V rats (NS). Our results indicate that signaling through the vagus nerve is necessary to maintain the anticipatory induction pattern of GLUT2 and sucrase. The persistent rhythm in both SGLT1 and GLUT5 indicates that (1) diurnal induction of these genes is independent of vagal innervation and (2) the procedure did not cause an overall loss of intestinal function. Thus, entrainment of anticipatory diurnal gene expression in the intestine occurs via two separate pathways that are differentially dependent on vagal input.     

Treatment of instrumental perforation of esophageal malignancy by transhiatal esophagectomy

Perforation of esophageal malignancy secondary to instrumentation is an uncommon but catastrophic complication. Esophageal perforation at the site of an obstructing esophageal malignancy precludes simple operative repair and mandates esophageal resection with reestablishment of gastro-intestinal tract continuity. In the past the standard surgical approach has involved transthoracic esophageal resection via thoracotomy. We have successfully treated four patients with perforated esophageal neoplasms by transhiatal esophagectomy and cervical esophagogastrostomy, thus avoiding thoracotomy in high-risk patients. We consider transhiatal esophagectomy an advantageous alternative in the management of selected cases of instrumental esophageal perforation adjacent to an esophageal malignancy.     

The epidemiology of bacteriuria in pregnancy

Bacteriuria in pregnancy is now easily detected by various techniques adapted to the office setting. It is importtant to screen for bacteriuria in pregnancy because 3%–10% of pregnant women will be positive for occult infection. Up to 30% thus infected will subsequently develop pyelonephritis later in pregnancy, which in turn is associated with premature labor and delivery. This entity must be detected and treated as early as possible in pregnancy to prevent these adverse effects.Presented at the Zambon Symposium on Bacteriuria in Pregnancy, International Urogynecological Association Annual Meeting, Riva del Garda, Italy, September 13, 1989.Dedicated to the memory of Edward H. Kass, MD, PhD.     

Multiple Implants for First Molar Prosthodontics

Problems that can occur when single implants are utilized to restore first molar teeth include the frequent loosening of screws, as well as screws and/or implant breakage. These may result from torquing and rotational movements of the prosthesis during masticatory and parafunctional mandibular movements. When sufficient bone and mesio-distal restorative space is present, the placement of two implants should be considered.     

Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.      

In-vitro interaction of azithromycin and fluoroquinolones against gram-positive and gram-negative bacteria

Objective: To determine the combined in-vitro effects of azithromycin plus the fluoroquinolone ofloxacin or lomefloxacin against gram-positive and gram-negative bacteria.
Methods: Fractional inhibitory (FIC) and fractional bactericidal concentration indices of azithromycin and the fluoroquinolone were determined using a microtiter-checkerboard method. Clinical isolates of Staphylococcus aureus, Streptococcus pneumoniae, Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pseudomonas cepacia, Haemophilus influenzae, Xanthomonas maltophilia and Acinetobacter calcoaceticus were studied. Fourteen strains of S. aureus were also studied in time-kill curves with azithromycin (4 mg/L), lomefloxacin (6 mg/L) and the two in combination.
Results: No synergism or antagonism was found in inhibitory assays. However, bactericidal assays revealed antagonism with some strains of S. aureus, S. pneumoniae, X. maltophilia, A. calcoaceticus, P. aeruginosa, P. cepacia, K. pneumoniae and E. coli. Kill-curve results with 14 strains of S. aureus showed no antagonism with four strains of methicillin-resistant S. aureus (MRSA), and antagonism with one strain of MRSA and seven methicillin-susceptible S. aureus (MSSA).
Conclusions: In-vitro exposure to combinations of azithromycin and a fluoroquinolone does not produce a synergistic effect. Antagonism was found in bactericidal assays against some gram-negative bacteria and MSSA; caution is therefore recommended in the use of macrolides and quinolones against these organisms.     

Primate gastric circulation: effects of catecholamines and adrenergic blockade.

The effects of intra-arterial injections and infusions of epinephrine, norepinephrine, and isoproterenol on gastric blood flow were studied in anesthetized baboons. Blood flow was measured electromagnetically before and after adrenergic blockade. The results for injected epinephrine and norepinephrine indicate these agents to be pure vasoconstrictors in the primate gastric circulation, and this response is attenuated by alpha-adrenergic blockade with phenoxybenzamine. Isoproterenol is a pure vasodilator, and its response is attenuated following beta-adrenergic blockade with propranolol. Intra-arterial infusions of epinephrine and norepinephrine (.05 mug kg-1 min-1) resulted in sustained vasoconstriction with no evidence of autoregulatory escape and no postinfusion "over-shoot." This study suggests that epinephrine and norepinephrine might provide alternatives to vasopressin as a vasoconstrictor for the control of upper gastrointestinal bleeding.