Myocardial Depressant Effects of Desflurane: Mechanical and Electrophysiologic Actions In Vitro

Background: The authors determined whether desflurane altered myocardial excitation-contraction coupling and electrophysiologic behavior in the same manner as isoflurane and sevoflurane.

Methods: The effects of desflurane on isometric force in guinea pig ventricular papillary muscles were studied in modified standard and in 26 mm K+ Tyrode solution with 0.1 [mu]m isoproterenol. Desflurane effects on sarcoplasmic reticulum Ca2+ release were also determined by examining its actions on rat papillary muscles, guinea pig papillary muscles in low-Na+ Tyrode solution, and rapid cooling contractures. Normal and slow action potentials were recorded using a conventional microelectrode technique. Ca2+ and K+ currents of guinea pig ventricular myocytes were examined.

Results: Desflurane (5.3% and 11.6%) decreased peak force to approximately 70% and 40% of the baseline, respectively, similar to the effects of equianesthetic isoflurane concentrations. With isoproterenol in 26 mm K+ Tyrode solution, desflurane markedly depressed late peaking force and modestly depressed early peak force. The rested state contractions of rat myocardium or guinea pig myocardium in low-Na+ Tyrode solution were modestly depressed, whereas rapid cooling contractures were virtually abolished after desflurane administration. Desflurane significantly prolonged the action potential duration. Desflurane reduced L-type Ca2+ current and the delayed outward K+ current but did not alter the inward rectifier K+ current.     

Pain management in ambulatory surgery.

Successful ambulatory surgery is dependent on analgesia that is effective, has minimal adverse effects, and can be safely managed by the patient at home after discharge. A number of studies have identified that the provision of effective postoperative analgesia is inadequate for a significant proportion of patients. The following discussion details the current available analgesic options for ambulatory surgery patients and the rationale for their use. Preemptive analgesia should be given to all patients unless there are specific contraindications. Consideration should be given to the use of long-acting oral COX-2 selective nonsteroidal anti-inflammatory drugs (NSAIDs) and long-acting oral opioids to treat postoperative pain. A standardized multimodal postdischarge analgesic regimen tailored to the patient's expected postoperative pain levels should be prescribed. Patient follow-up by telephone questionnaire will confirm those surgical procedures that result in mild or moderate-to-severe postoperative pain and the effectiveness of treatment plans.     

Distinct osteogenic mechanisms of bones of distinct origins

Mammalian bones have three distinct origins (paraxial mesoderm, lateral plate mesoderm, and neural crest) and undergo two different modes of formation (intra-membranous and endochondral). Bones derived from the paraxial mesoderm and lateral plate mesoderm mainly form through the endochondral process. During this process, hypertrophic chondrocytes play a vital role in inducing both osteogenesis and angiogenesis. One of the essential osteogenic factors secreted from hypertrophic chondrocytes is Indian hedgehog (Ihh). In contrast, bones derived from the neural crest mainly form through the intramembranous pro-cess and do not require Ihh. Thus, depending on their origin, bones have distinct signaling properties, which need to be considered in the research and application of bone biology.Presented at the 18th Annual Research Meeting of the Japanese Orthopaedic Association, Kitakyushu, Japan, October 17, 2003     

Effects of Botulinum Toxin Type A on Contouring of the Lower Face

BACKGROUND: Masseteric muscle hypertrophy is an uncommon dition represented as a swelling of the masseter muscle. Recent reports have demonstrated the successful use of botulinum in the treatment of masseteric hypertrophy. OBJECTIVE: This study was a prospective trial to evaluate the effectiveness of botulinum toxin type A (Botox) in the treatment of masseteric muscle hypertrophy according to doses of 10, 20, and 30 U. MATERIALS AND METHODS: Twenty-two patients were referred to the dermatologic clinic for the management of masseteric muscle hypertrophy. Ultrasonographic measurements of the thickness of the masseter muscle were performed, and clinical photographs were taken before treatment and 1, 2, 3, 4, 6, and 9 months after the treatment. RESULTS. The median values of percentage reduction of muscle mass were 10.3%, 16.5%, 23.7%, 24.7%, 21.6%, 16.5% in the 10 U group; 11.9%, 18.8%, 24.8%, 27.7%, 26.7%, and 21.8% in the 20 U group; and 12.0%, 19.4%, 25.0%, 27.8%, 37.8%, and 24.1% in the 30 U group. CONCLUSION. The adequate dose of botulinum toxin type A for treatment of masseteric muscle hypertrophy should be above 20 U. The effect of botulinum toxin type A is maintained for at least 9 months as the treatment of masseteric muscle hypertrophy.     

Long-acting beta 2-adrenoceptor agonists: a new perspective in the treatment of asthma.

New long-acting beta 2-adrenoceptor agonists, formoterol and salmeterol, may soon appear in several European countries for treatment of asthma. This review examines currently available information and compares the basic pharmacology and describes the clinical effects of these new drugs. The long duration of bronchodilation seen in clinical studies seems to be similar, whereas in isolated tissues there might be a difference in the binding characteristics to the beta 2-adrenoceptor. Long-acting beta 2-agonists could have an inhibitory effect on inflammatory events related to asthma, but the clinical relevance of these effects is not clear at present. Long-term studies up to one year with both new drugs have not shown any unexpected side-effects, and no tachyphylaxis to beta-adrenoceptor stimulation has been reported. Patients appear to strongly prefer the new drugs compared to the short-acting beta 2-agonists. The potential place for these drugs in the treatment of asthma is discussed and some pitfalls pointed out. It is likely that the long-acting beta 2-agonists will be beneficial to many asthmatic patients.     

Intraocular pressure and axial length in children

The intraocular pressure and the anteroposterior length of the eye are of great clinical importance for the diagnosis and management, before and after surgery, of congenital glaucoma. It is well-known that normal intraocular pressure in children is different from the normal levels in adults. We performed measurements of intraocular pressure and axial length in 141 children who had been admitted for eye problems other than glaucoma. The intraocular pressures were measured with the Perkins hand-held applanation tonometer at the beginning of general anesthesia. Simultaneously, A-scan ultra-sound measurements of the axial lengths of the eyes were made. In 10 children under the age of two years, the intraocular pressure was 11.85 +/- 1.35 mmHg. In 79 children from two to seven years, the intraocular pressure was 12.80 +/- 1.73 mmHg. In 52 children from seven to 15 years, the intraocular pressure was 13.31 +/- 1.79 mmHg. The axial lengths of the eyes in children under the age of two years, from two to seven years, and from seven to 15 years, were 21.31 +/- 0.97 mm, 22.04 +/- 0.92 mm, and 23.22 +/- 1.00 mm, respectively. These results were considered to be guidelines for measuring intraocular pressure and axial length in children suspected of having congenital glaucoma. The differences of intraocular pressures stated by other authors are due to early measurement of the intraocular pressure at the beginning of general anesthesia.     

L-2-oxothiazolidine-4-carboxylate as a cysteine precursor: efficacy for growth and hepatic glutathione synthesis in chicks and rats

Chick and rat experiments were conducted to determine the efficacy of L-2-oxothiazolidine-4-carboxylate (OTC) as a cysteine (Cys) precursor for growth and hepatic glutathione (GSH) biosynthesis. Isosulfurous graded increments of OTC and Cys were added to Cys-free purified amino acid diets that were adequate in methionine. Curvilinear responses to both Cys and OTC for chicks and rats were obtained. Hepatic GSH accumulated in chicks only at dietary Cys levels above 0.10%. In rats, hepatic GSH increased linearly as dietary Cys content increased from deficient to adequate and from adequate to excessive. Utilization of OTC by chicks was as efficacious as isosulfurous levels of Cys for growth and hepatic GSH biosynthesis. In rats, OTC was slightly inferior to Cys for growth and hepatic GSH biosynthesis. Exponential regression slope-ratio growth efficacy values for OTC were 78.5% for chicks and 70.2% for rats; multiple linear regression slope-ratio GSH biosynthesis efficacy values were 80.3% for chicks and 83.7% for rats. It is concluded that orally administered OTC is active as a Cys precursor.