Synthesis of octadecynoic acids and [1-14C] labeled isomers of octadecenoic acids.

Geometric and positional isomers of [1-14C] octadecenoic acids have been synthesized by modifications of published procedures. Positional isomers of octadecynoic acids also have been synthesized to obtain the geometric and positional isomers of the unlabeled octadecenoic acid analogs. The syntheses were accomplished by coupling a haloalkyl compound with a substituted acetylene using n-butyl lithium in hexamethylphosphoramide. The coupled product, either a 17- or 18-carbon acetylenic alcohol, could be semihydrogenated and chain extended to afford a carboxy labeled derivative, could be partially hydrogenated and chain extended to afford a carboxyl labeled cis- or trans-octadecenoic acid in the former case. In the latter case, octadecynoic, cis-octadecenoic or trans-octadecenoic acids could be obtained by the appropriate reactions. The methods used in this study enabled the synthesis of 14C-labeled fatty acids in generally higher yields and by simpler reactions than were previously possible.

Composition of mixed octadecadienoates via ozonolysis, chromatography and computer solution of linear equations.

An approach to the analysis of 55 possible nonconjugated positional isomers of octadecadienoic acid is described and tested with mixtures of individual synthetic methyl esters. In the first example, by ozonolysis a seven-component mixture consisting of cis,cis 5,12-, 6,10-, 6,11-, 6,12-, 7,12-, 8,12-, and 9,12-octadecadienoates was converted to aldehydes, aldehyde-esters and dialdehydes. These fragments were separated on a 50 m X 0.2 mm free fatty acid phase (FFAP) vitreous silica capillary column. Equations for an arbitrarily restricted 12 X 15 matrix of linear simultaneous equations and a computer solution of the matrix provided the composition of the initial methyl octadecadienoate mixture. The power and significance of this method became apparent with the observation that only two of the seven isomers in the known mixture were resolved as single peaks by state-of-the-art capillary gas chromatography, but all seven were identified and estimated with acceptable error by the ozonolysis-capillary gas chromatography-computer procedure. In a generalized approach to the analysis of the 55 possible nonconjugated isomers, a computer program selects the appropriate matrix of linear simultaneous equations based on the aldehyde data supplied by the analyst. Twenty of 21 combinations of seven isomeric esters taken five at a time have been analyzed to assess the efficiency of the method. To illustrate applicability at this stage of development, the method has been used to analyze the diene products of the hydrazine reduction of gamma-linolenic acid and the diene products from the biological desaturation of isomeric monoenes.(ABSTRACT TRUNCATED AT 250 WORDS)

Procalcitonin as a diagnostic marker in patients with aspiration after closed head injury.

BACKGROUND: Aspiration of gastric content frequently induces early onset of pneumonia in patients with impaired consciousness after closed head injury and thus worsens the prognosis. Early detection of aspiration and appropriate therapy are essential. The purpose of the study was to assess the diagnostic value of procalcitonin (ProCT) in aspiration of gastric content and to evaluate its prognostic impact in patients with closed head injury. METHODS: Twenty-three patients with isolated closed head injury (Glasgow Coma Scale [GCS] score < or = 8) were studied. Bronchoscopy was done on admission; chest radiographs and routine laboratory examination including C-reactive protein were performed daily. ProCT was analyzed 12, 24, 36 and 72 hours after trauma using an immunoluminometric assay. RESULTS: ProCT was higher throughout the study period in 9 patients with persistent radiological signs suspect for aspiration of gastric content and there was evidence of aspiration of gastric content during bronchoscopy on admission. Median ProCT values of 1.397 ng/ml (range, 0.372 to 8.358 ng/ml) on admission increased to 2.144 ng/ml (range, 0.716 to 6.910 ng/ml) 24 hours after trauma, and then decreased to baseline values of 1.711 ng/ml (range, 0.611 to 6.639 ng/ml) as early as 36 hours after trauma. In patients without signs of aspiration of gastric content, ProCT values did not exceed 0.418 ng/ml. Non-survivors had higher serum levels of ProCT throughout the study period. CONCLUSION: Our findings suggest that ProCT is a useful diagnostic marker for detecting aspiration of gastric content while the prognostic value of ProCT for predicting survival after isolated closed head injury was moderate.

A prospective randomized trial comparing the cuffed oropharyngeal airway (COPA) with the laryngeal mask for elective minor surgery in female patients.

OBJECTIVE: The cuffed oropharyngeal airway (COPA), a modified Guedel-type airway with a cuff at the distal end, has recently been introduced into anesthetic practice. The aim of this study was to compare the COPA with the well established laryngeal mask airway (LMA). Special consideration was granted to the difficult airway. PATIENTS AND METHODS: Two hundred and fifty-two women of ASA class I or II undergoing elective gynecological or breast surgery under general anesthesia were randomly assigned to either cuffed oropharyngeal or laryngeal mask airway management. Insertion and removal of the device, airway maintenance throughout the procedure, and postoperative course and complications were assessed. RESULTS: A patent airway was obtained with either device in all patients. Global first-time success rates for insertion were similar in the two study groups. Initial failure of correct placement occurred more frequently in the COPA as compared to the LMA group if the interincisor gap was < 5 cm and mandibular protrusion impossible (p < 0.01). Neither thyromental distance nor Mallampati scores nor body mass index (BMI) were of relevance for insertion success. The incidence of postoperative complaints and of mucosal injuries was significantly higher with the LMA. CONCLUSION: On the whole, high overall success and low complication rates render COPA and LMA equally suitable for routine anesthetic airway management.

Sonographic measurement of needle insertion depth in paravertebral blocks in women.

Single-injection paravertebral block offers adequate unilateral analgesia for thoracic and upper abdominal surgery. This technique is easy to learn but there is a risk, albeit low, of pleural puncture. The aim of the study was to determine whether sonographic measurements of the distances from the skin to the transverse process and to the parietal pleura are useful for calculating the required depth of needle insertion. Before puncture of the paravertebral space, the distances from the skin to the transverse process and to the parietal pleura were measured by sonography. The deviation of the needle from the horizontal plane was measured and an angle correction for the insertion depth was calculated. Twenty-two women undergoing elective unilateral breast surgery were studied. Sonographic visualization of the transverse process and the parietal pleura and measurement of their distances from the skin was successful in all women. Puncture of the paravertebral space failed in one obese woman. There was a very close correlation between needle insertion depth from the skin to the transverse process and the distance measured by ultrasound if angle correction was used (adjusted r2=0.95). Similarly, there was excellent correlation between the angle-corrected ultrasound distance from the skin to the parietal pleura and the distance from the skin to the paravertebral space (adjusted r2=0.92).

Sevoflurane anaesthesia in paediatric patients: better than halothane?

Forty-two children (aged 2-16 years) were randomly assigned to receive either sevoflurane (n = 21) or halothane (n = 21) in nitrous oxide/oxygen. After pre-medication with midazolam, anaesthesia was induced by facemask and the anaesthetic concentration was increased until loss of eyelash reflex (sevoflurane, 6%; halothane, 2.5%). Thereafter, 1-1.5 MAC of the inhalational agents were maintained until skin closure. Intra-operative analgesia was provided either by intermittent intravenous (i.v.) bolus doses of fentanyl (2-3 micrograms kg-1) or by a regional blockade. Induction was smooth and the time to loss of eyelash reflex was slightly shorter with sevoflurane than with halothane, the difference not quite reaching statistical significance (P = 0.06). In both groups, heart rate remained stable and blood pressure decreased significantly during induction. Haemodynamic parameters remained stable during anaesthetic maintenance; no cardiac dysrhythmias were observed. Emergence time with sevoflurane was 12.9 min vs. 16.3 min with halothane, but this difference was not statistically significant. It is concluded that sevoflurane is as suitable for paediatric patients as halothane. The slightly faster emergence time offered by sevoflurane over halothane was of no clinical significance in the present study.

Unusual isomeric polyunsaturated fatty acids in liver phospholipids of rats fed hydrogenated oil.

Linoleic acid (18:2 omega 6) and linolenic acid (18:3 omega 3) are precursors of two series of essential fatty acids (EFA) formed by alternate desaturations and elongations. In EFA deficiency (EFAD), oleic acid (18:1 omega 9) and palmitoleic acid (16:1 omega 7) undergo the same reactions to form polyunsaturated fatty acids (PUFA) of other structures. Partially hydrogenated soybean oil (PHSO) contains isomeric 18:1 acids that can be converted to unusual isomers of 18:2 by liver microsomes. To test whether 18:2, 20:3, and 20:4 of unusual structure occur in phospholipids as a consequence of EFAD or ingestion of PHSO, rats were fed corn oil, an EFA-deficient diet, or PHSO to provide isomeric 18:1 acids. At 2.5 months the phospholipids were isolated from livers and converted to methyl esters, and the 18:2, 20:2, 20:3, and 20:4 fractions were isolated. The 18:2 and 20:2 fractions were ozonized, and, by using a computer solution of simultaneous equations, the structures and proportions of each isomer were calculated. The 20:3 and 20:4 fractions were analyzed by ozonolysis and capillary gas chromatography. When corn oil was fed, the major isomer in each group was 9,12-18:2, 11,14-20:2, 8,11,14-20:3, and 5,8,11,14-20:4. Patterns in EFAD- and PHSO-fed groups were more diverse, with large proportions of unusual isomers. Feeding EFA-deficient diet and PHSO induced measurable amounts of unusual PUFA at each step of the cascade, and these PUFA may compete in metabolism of normal PUFA and are substrates for oxidative formation of autacoids of unknown structures and function.

Single-injection paravertebral block compared to general anaesthesia in breast surgery.

BACKGROUND: Breast surgery is frequently associated with post-operative nausea, vomiting, pain and painful restricted movement. Paravertebral block may be an alternative to general anaesthesia for this type of surgery. We studied the single-injection paravertebral block at the level of T4 and report a comparison of single-injection paravertebral block to general anaesthesia for breast surgery. METHODS: After written informed consent was obtained, 86 patients were enrolled in this prospective study. Forty-four women were randomly allocated to receive a single-injection paravertebral block at the level of T4, while 42 women received general anaesthesia. The surgical procedures varied from lumpectomy (wide local excision of a tumour) to modified radical mastectomy with axillary dissection. The block was performed according to the guidelines described by Eason and Wyatt using 0.3 ml x kg(-1) (maximum dose 150 mg) of bupivacaine 0.5%. The skin and the underlying tissues were infiltrated with local anaesthetic solution two fingers (about 3 cm) from the anatomical midline and level with the cephalad end of the vertebral spine. RESULTS: Time for performance of blocks lasted from 4 to 9 min. Recovery from anaesthesia or sedation was shortened, while postoperative pain scores (VAS), the incidence of vomiting and the requirement for analgesics were lower in the paravertebral group. Less painful restricted movement was observed in the paravertebral block group. Paravertebral block was inadequate in 6.8% of patients. Epidural spread with paraparaesis and Horner triad was assumed in one patient. CONCLUSION: Single-injection paravertebral block at the level of T4 represents a suitable alternative to general anaesthesia in women undergoing breast surgery.

Electrical stimulation of the vestibular system prevents postoperative nausea and vomiting.

BACKGROUND: Electrical stimulation of the vestibular system may prevent nausea and vomiting. We studied the influence of transcutaneous impulse stimulation in prevention of postoperative nausea and vomiting (PONV) following gynaecological surgery. METHODS: In this randomised study 70 women undergoing elective gynaecological surgery under general anaesthesia were assigned to receive either the activated (stimulation group) or the inactivated (non-stimulation group) impulse stimulator. The stimulator comprises the stimulator itself, two negative electrodes on a headset applied over both mastoid processes and a nuchal positive electrode. The device yielded a pulse frequency of 5 Hz direct current, individually adjustable between 0.5 and 4 mA. A trapezoid stimulation of 50 ms was applied. Nausea, vomiting, dizziness and the amount of antiemetic drugs used were assessed during the first 4 h postoperatively. RESULTS: Lower postoperative nausea scores with a lower incidence of vomiting and postoperative dizziness were found in the stimulation group. A lower amount of antiemetic drugs was needed in the stimulation group when compared to the non-stimulation group (P<0.01 between groups). CONCLUSION: This study suggests that electrical stimulation of the vestibular system may be useful in prevention of PONV.