Mitochondrial Injury in Human Acute Carbon Monoxide Poisoning: The Effect of Oxygen Treatment

The best oxygen therapy for acute carbon monoxide poisoning (ACOP) remains unestablished. Reported mitochondrial complex IV (mtCIV) inhibition, together with carboxyhaemoglobin (COHb)-induced hypoxia, may influence acute clinical symptoms and outcome. To “mitochondrially” evaluate treatment efficacy, we correlated intoxication severity and symptoms with mitochondrial function (mtCIV activity) and oxidative stress (lipid peroxidation) in 60 poisoned patients and determined ACOP recovery depending on either normobaric or hyperbaric oxygen therapy along a 3-month follow-up. In the present article we positively evaluate mtCIV as a good marker of ACOP recovery, treatment effectiveness, and late neurological syndrome development, which advocates for hyperbaric oxygen therapy as the treatment of choice. However, we discourage its usefulness as a severity marker because of its excessive sensitivity. We additionally evaluate oxidative stress role and prognostic factors for neurological sequelae development.     

Termination of Reentrant Propagation By a Single Stimulus: A Model Study

A computer model of a ring-shaped one-dimensional cardiac fiber was used to examine responses of reentrant propagation to premature stimuli applied under different degrees of head-tail interaction. Two different types (type I and type II) of termination window (TW) were identified. The type I TW was generated by functional inhomogeneity created by reentrant propagation. The width of the type I TW was proportional to the degree of cellular uncoupling. In contrast, uniform reduction in sodium channel conductance decreased the width of type I TW. The type II TW was generated by electrical alternans created by the head-tail interaction of the reentrant action potential. It was demonstrated that electrical alternans were most significant in medium degree head-tail interaction. For stronger or weaker head-tail interaction, the electrical alternans tended to decrease. The type II TW was located in excitable gups following reentrant action potentials of short duration. Its size was proportional to the degree of electrical alternans. The type II TW was usually much larger than the type I TW. A premature conditioning stimulus induced alternans and created a type II TW. This response implies that a conditioning stimulus could facilitate greatly the termination of clinical reentrant arrhythmias by programmed electrical stimulation.     

Propofol reduces the incidence of vomiting after tonsillectomy in children

We compared the effect of a propofol-based anaesthetic to an isoflurane-based anaesthetic on the incidence of postoperative vomiting in children following tonsillectomy. Thirty-nine children were enrolled in the study and randomized to receive one of the proposed anaesthetics. All patients underwent a mask induction with halothane, nitrous oxide, and oxygen. Intravenous access was established and all children received fentanyl (2–4 μg·kg^-1) i.v., mivacurium (0.3 mg·kg^-1) i.v. and acetaminophen (10–15 mg·kg^-1) p.r. Following tracheal intubation, patients received either isoflurane (0.8–1.6%) or propofol (120–180 μg·kg^-1 min^-1) i.v. with nitrous oxide 70%/oxygen 30% for maintenance of anaesthesia. Vital signs were maintained within 20% of baseline. All patients were extubated in the operating room. PACU nursing staff recorded episodes of vomiting for 4–6 h prior to discharge. A telephone interview the following day was also used for data recovery. Age, sex, and duration of the procedure were not significantly different between the two study groups. Of 19 patients who received propofol, four vomited (21%); in contrast, of the 20 patients who received isoflurane, 11 vomited (55%). This difference is significant (P= 0.048 two-tailed Fisher's Exact Test). These data suggest that using propofol for anaesthesia can diminish the incidence of vomiting following tonsillectomy.     

Reentry: Insights From Theoretical Simulations in a Fixed Pathway

Reentrant Activity in Cardiac Tissue. This review article summarizes theoretical insights into the principles and mechanisms associated with reentrant activity in cardiac tissue. A mathematical ring model is used in computer simulations to investigate, at the cellular level, mechanistic aspects of initiation, perpetuation, and termination of reentry. Taking advantage of the ability to compute membrane processes in this model, we relate dynamic properties of the reentrant action potential (e.g., beat-to-beat alternans) to the underlying kinetics of membrane ionic channels. Effects on reentry of inhomogeneities in refractoriness, excitability, cellular coupling at gap junctions, and fiber cross-section are also studied.     

Recurrent Laryngeal Nerve Paralysis Following Pacemaker Introduction

Electrode insertion to the heart via subclavian vein puncture has become a commonplace procedure. A case is presented in which employment of this route led to permanent paralysis of the recurrent laryngeal nerve. (PACE, Vol. 5, July-August, 1982)     

Menopause Is Associated With a Significant Increase in Blood Monocyte Number and a Relative Decrease in the Expression of Estrogen Receptors in Human Peripheral Monocytes

PROBLEM : The clinical significance of the differential expression of estrogen receptor (ER) in human monocytes was evaluated. METHOD : Two color flow cytometry analysis was used on peripheral blood samples of young and postmenopausal females and postmenopausal females treated with estrogen replacement therapy. In addition, the monocyte and lymphocyte counts and the blood estrogen levels of each patient were determined. RESULTS : During menopause there is a significant decrease in the percentage of ER positive monocytes, and an increase in blood monocyte number, which declines following estrogen replacement therapy to values of the young. CONCLUSIONS : These findings suggest that estrogen modulates the monocyte numbers and its effects may be mediated through the ER in the monocytes.