Comparison of 0.25% ropivacaine and bupivacaine for epidural analgesia for labor and vaginal delivery

STUDY OBJECTIVE: Part 1: To measure ropivacaine levels in the mother and infant at delivery after continuous lumbar epidural infusion. Part 2: To compare epidural ropivacaine to epidural bupivacaine for labor analgesia in regard to effectiveness, motor blockade, and maternal and neonatal effects. DESIGN: Part 1: Open-labelled, non-blind study. Part 2: Randomized, double-blind study. SETTING: Labor and delivery units of two academic hospitals. PATIENTS: Part 1: 20 ASA physical status I and II parturients in active labor. Part 2: 81 ASA physical status I and II parturients in active labor. INTERVENTIONS: For Part 1, 8 to 12 ml of 0.25% ropivacaine was administered through a lumbar epidural catheter to achieve a T10 dermatomal sensory level. An infusion of 0.25% ropivacaine, 8 to 10 ml/hr, maintained this sensory level. Maternal and umbilical cord blood samples obtained at delivery were analyzed for ropivacaine concentration. For Part 2, anesthetic management was similar to that previously described except patients were randomized to receive either 0.25% ropivacaine or 0.25% bupivacaine. Onset, regression, maximal spread of sensory block, and onset and degree of motor blockade were measured. Contraction pain as assessed using a visual analog scale (VAS), maternal blood pressure, and heart rate were determined every 5 minutes until a stable VAS-contraction score was achieved, and every 30 minutes thereafter. Neonatal assessment included Apgar scores and neurologic and adaptive capacity scores (NACS) at 15 minutes, 2 hours, and 24 hours. MEASUREMENTS AND MAIN RESULTS: For Part 1, the total and free maternal arterial concentrations of ropivacaine at delivery were 0.64 +/- 0.14 microgram/ml and 0.10 +/- .02 microgram/ml, respectively; the umbilical venous total and free concentrations were 0.19 +/- 0.03 microgram/ml and 0.12 +/- 0.07 microgram/ml, respectively (n = 12). The umbilical arterial and venous concentrations did not differ for both the free and total concentrations. For Part 2, there was no difference between ropivacaine and bupivacaine in the variables measured. Umbilical cord gases and Apgar scores were not different between the two groups; NACS were higher at 15 minutes and 2 hours in the ropivacaine group (p < 0.05) than the bupivacaine group. CONCLUSION: Both ropivacaine and bupivacaine produced excellent analgesia for labor with no major adverse effect on the mother or neonate.     

Reinterpretation of luminiscence properties of neurotoxins from the venom of Middle-Asian corba Naja oxiana eichw

A new interpretation of previous work (Bukolova-Orlova, T. G., Burstein, E.A. and Yukelson, L. Ya (1974) Biochim. Biophys. Acta 342, 272-280) and some new data on the luminescence of neurotoxins I and II from Naja oxiana venom is given, based on the newer data on their complete amino acid sequences. Very effective excitation energy exchange exists between Trp-27 and Trp-33 in neurotoxin I and between Trp-27 and Trp-28 in neurotoxin II, Which results in the tryptophanyl fluorescence spectra of each of the proteins seeming to be monocomponent ones. The lowered fluorescence quantium yield value, the shortened phosphorescence lifetime (80% of the emission has tau p less than 0.5 s, 20% has tau p = 4.8 s, comparing with usual tau p = 5.5-5.9 s) and decreased phosphorescence to fluorescence ratio (0.042, as compared to the usual 0.4-0.7) for neurotoxin I suggest that the indole chromophore of Trp-27 and/or Trp-33 are in contact with heavy sulfur atoms of disulfide, most probably of Cys(28)-Cys(32). Tryptophanyls in neurotoxin II are exposed to the solvent, however their accessibility in relation to that of the free tryptophan to the negatively charged quencher I- (0.455) is much higher than that for the positively charged Cs+ (0.08), which is probably due to the proximity of cationic Lys-25, Lys-26 and His-31. The difference of accessibility to the negative and positive quenchers is even more pronounced in the case of the neurotoxin I (1.04 and 0 +/- 0.02, respectively), though in its chromophore vicinity along the primary structure there is only one cationic group, Lys-25. This fact together with the analysis of the amino acid sequence, suggest that the space folding of this polypeptide results in the close proximity of Trp-27 and/or Trp-33 with the C-terminal peptide segment 67-73, which contains four cationic groups (His-67, Lys-69, Lys-71 and Arg-72).     

Low molecular weight viral RNAs transcribed by RNA polymerase III during adenovirus 2 infection

Nuclei isolated from human cells productively infected with adenovirus 2 have been shown to synthesize four low molecular weight RNA species which hybridize efficiently to viral DNA. One species corresponds to the 5.5S or VA RNA (Ohe, Weissman, and Cooke, 1969), and is designated V156. The other three species are novel and have been designated V200, V140, V130, since they are approximately 200, 140, and 130 nucleotides in length, respectively. These viral RNAs retain their distinct electrophoretic properties after denaturation with formamide. RNA species with electrophoretic mobilities similar to those of the V200, V156, and V140 RNAs have been found in the cytoplasmic fraction of cells at late times after adenovirus infection. In isolated nuclei, the V200, V156, V140, and V130 RNAs are all synthesized by DNA-dependent RNA polymerase III, since synthesis is sensitive to high but not to low concentrations of alpha-amanitin. The synthesis of these low molecular weight RNAs continues for a prolonged period of time in isolated nuclei, suggesting that reinitiation occurs. Adenovirus 2 DNA fragments obtained by digestion with restriction endonucleases Eco RI and Sma I were used to map the location of the DNA sequences which encode the RNAs. All the low molecular weight RNAs hybridized to a region of the genome between o.18 and 0.38 fractional lengths from the left end of the adenovirus genome, suggesting that the respective DNA sequences are clustered. Other nonviral low molecular weight RNAs are synthesized in nuclei isolated from infected cells. These include the cellular 5S rRNA species which was minitored by its hybridization to purified 5S DNA from Xenopus laevis.     

Seasonal variation in the capacity of the bank vole to infect larval ticks (Acari: Ixodidae) with the Lyme disease spirochete, Borrelia burgdorferi

Seasonal variation in the capacity of bank voles, Clethrionomys glareolus (Schreber), to infect larval Ixodes ricinus (L.) ticks with Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner was examined from May through October 1991 at Bogesund, near Stockholm in south-central Sweden. Although larval infestations of bank voles were greatest in June and July, nearly 70% of all larval ticks infected with spirochetes by bank voles at this site became infected during August and September. Seasonality of infectivity was related to the degree of earlier nymphal infestation on voles as well as to the age composition of the vole population. These factors may influence the infectivity of other rodent reservoirs of B. burgdorferi, both in Europe and North America. Moreover, in determining the reservoir potential of tick hosts, a host population's spirochetal infectivity should be determined for the entire period of larval infestation rather than just during the period of peak larval infestation.     

Detection of small changes in body composition by dual-energy x-ray absorptiometry

The ability of dual-energy x-ray absorptiometry (DEXA) to detect small changes in body composition was studied in 17 men and women during a dehydration-rehydration protocol. Scale weight (BW) and total mass (TM) from DEXA were highly related (r > 0.99) as were estimates of fat-free mass (r = 0.99) and percent fat (r = 0.97) from DEXA and densitometry. Changes in BW of approximately 1.5 kg due to fluid loss and gain were highly correlated (r = 0.90) with both changes in TM and soft-tissue mass (STM) by DEXA but less so (r = 0.67) with changes in lean-tissue mass (LTM). Mean changes in TM, STM, and LTM were not different (P > 0.05) from changes in BW. Estimates of bone mass and fat were unaffected by changes in hydration. We conclude that DEXA is able to detect small individual changes in TM and STM and is also useful for detecting group changes in LTM.     

Lead poisoning from drinking Kombucha tea brewed in a ceramic pot

Kombucha tea is an alternative therapy that is gaining popularity as a remedy for a diverse range of ailments. We report two cases of symptomatic lead poisoning requiring chelation therapy in a married couple who had been drinking Kombucha tea for six months, brewing the tea in a ceramic pot. We postulate that acids in the tea eluted lead from the glaze pigment used in the ceramic pot, in a manner analogous to elution of lead from crystal decanters by wine and spirits.