Effects of cimetidine and ranitidine on local anesthetic central nervous system toxicity in mice

The effects of cimetidine (5-200 mg/kg), ranitidine (1-100 mg/kg), or saline on local anesthetic central nervous system toxicity was studied when administered 20 min before the administration of lidocaine (30-80 mg/kg) or 2-chloroprocaine (50-250 mg/kg) to female white CD-1 mice. All drugs were administered intraperitoneally. The 50% convulsive dose (CD50) was determined for each drug and dose combination. Pretreatment with cimetidine resulted in a significant, dose-dependent decrease in the CD50 of lidocaine, whereas ranitidine pretreatment did not significantly alter the lidocaine CD50. A dose of cimetidine (15 mg/kg) that caused a significant decrease in 2-chloroprocaine CD50 (from 180 to 110 mg/kg) caused only an insignificant decrease in lidocaine CD50 (from 59 to 54 mg/kg). If these results can be applied to clinical doses in humans, ranitidine may be a safer premedicant than cimetidine with regard to interactions with local anesthetics.

Possible requirement of collagen gel substratum for production of mucin-like glycoproteins by primary rabbit tracheal epithelial cells in culture

Primary rabbit tracheal epithelial cells growing on either plastic surface or collagen gel produce high molecular weight glycoconjugates. Biochemical characterization of these materials show they are exclusively hyaluronic acid when cells are grown on plastic surface, but a mixture of hyaluronic acid and mucin-like glycoproteins when grown on collagen gel. This research suggests that the substratum plays an important role in the maintenance or differentiation or both of mucous cells in culture.

Biochemical characterization of mucous glycoproteins synthesized and secreted by hamster tracheal epithelial cells in primary culture

Hamster tracheal epithelial cells growing on type I collagen gel synthesize and secrete high molecular weight glycoconjugates which elute in the void volume upon Sepharose CL-4B column chromatography. The presence of any proteoglycans in this void volume material was ruled out based on both enzymatic analysis and behavior on DEAE-ion exchange chromatography. Based on the incorporation of radioactive precursors, followed by strong acid hydrolysis or neuraminidase digestion, the material was shown to contain sialic acid, fucose, galactose, N-acetylglucosamine, N-acetylgalactosamine, and sulfate. Complete susceptibility to papain digestion and reductive beta-elimination suggests that the material consists of O-linked glycoproteins. The identification of N-acetylgalactosaminitol in the beta-eliminated oligosaccharides confirms this notion. The molecular weight of the oligosaccharides following beta-elimination ranges from 4,000 to 15,000. We conclude that the high molecular weight glyconjugates produced by hamster tracheal epithelial cells in primary culture are mucous glycoproteins based on size, sensitivity to alkaline borohydride treatment, and monosaccharide composition. Further characterization of these mucous glycoproteins showed both size and charge microheterogeneity among molecules. Detailed structural analysis of oligosaccharides of these mucous glycoproteins is currently under way.

Pharmacokinetics, placental transfer, and neonatal effects of vecuronium and pancuronium administered during cesarean section

Vecuronium and pancuronium were compared for placental transfer, pharmacokinetic variables, and neonatal effects during cesarean section under general anesthesia. Eighteen women underwent rapid-sequence intravenous induction using d-tubocurarine, succinylcholine, thiopental, and oxygen. Immediately after tracheal intubation, an intravenous injection of vecuronium (n = 11) or pancuronium (n = 7), 0.04 mg/kg, was given. Maternal venous blood samples were obtained before induction and at frequent intervals for 4 h after administration of vecuronium or pancuronium. Also, maternal venous and umbilical-cord arterial and venous blood samples were obtained at delivery. To describe placental transfer and maternal pharmacokinetics of the drugs, serum drug concentrations were determined using single-ion-monitoring mass spectrometry. The Apgar score and Neurologic and Adaptive Capacity Score (NACS) were used to evaluate neonatal condition. Both drugs crossed the placenta, as demonstrated by low concentrations of vecuronium (8.5-26.4 ng/ml) or pancuronium (12.2-34.2 ng/ml) found in umbilical venous blood. At delivery, the ratio of the drug concentration in umbilical venous blood to that in maternal venous blood was 0.11 +/- 0.02 for vecuronium and 0.19 +/- 0.03 for pancuronium. Vecuronium had a more rapid clearance (6.4 +/- 0.4 ml X kg-1 X min-1, mean +/- SE) and a shorter elimination half-life (36 +/- 1.8 min) than pancuronium (3.0 +/- 0.1 ml X kg-1 X min-1 and 72 +/- 6 min, respectively). No other pharmacokinetic differences were found between the drugs. Neonatal outcome was not affected adversely by either muscle relaxant, as assessed by Apgar scores and NACSs . The short duration of action, the minimal placental transfer, and the apparent lack of clinical neuromuscular effects on the newborn suggest that vecuronium should be a useful muscle relaxant for cesarean section.

Occupational burns

Certain occupations cause particular kinds of burn. Minor burns are usually neglected. Observation of industrial workers during routine annual medical examination found many workers with minor occupational burns and their sequalae. Some were so characteristic that they can be regarded as occupational marks.

Epidural bupivacaine, chloroprocaine, or lidocaine for cesarean section--maternal and neonatal effects

The effects of epidural anesthesia on maternal blood pressure, newborn Apgar scores, neonatal acid-base status, and the early neonatal neurobehavioral scale (ENNS) were studied in 54 pregnant women undergoing cesarean section. Maternal and neonatal blood levels of the local anesthetics were also determined. Group 1 (n = 16) received 0.75% bupivacaine, group 2 (n = 18) received 3% chloroprocaine, group 3 (n = 11) received 2% lidocaine, and group 4 (n = 9) received 2% lidocaine with 1:200,000 epinephrine. The incidence of maternal hypotension did not differ significantly among the four groups. Fetal outcome as determined by Apgar scores, acid-base status, and neurobehavioral testing was equally good in all four groups. At delivery, the fetal/maternal concentration ratio of bupivacaine was 0.27, that of lidocaine without epinephrine 0.48, and that of lidocaine with epinephrine 0.58. Chloroprocaine was detected in 12 maternal samples, in seven umbilical venous samples, and in six umbilical arterial samples. It is concluded that epidural anesthesia as administered in this study had no adverse effect on the newborn Apgar scores, cord acid-base status, or the ENNS.

Yeast 2-microns plasmid DNA replication in vitro: purification of the CDC8 gene product by complementation assay

Extracts of the yeast Saccharomyces cerevisiae support DNA replication on exogenous yeast 2-microns plasmid DNA templates. A crude extract from a S. cerevisiae cell division cycle mutant, cdc8-1, expressed the temperature-sensitive phenotype since it could be inactivated at 42 degrees C in vitro. This heat-inactivated extract was fully complemented by the addition of either wild-type or cdc8-1 single-stranded DNA binding protein (SSB). restoration by SSB of the activity of the mutant cell extract allowed replication like that of a wild-type crude extract, as shown by bidirectional DNA synthesis from the in vivo origin. The DNA binding protein specifically stimulates the reaction catalyzed by yeast DNA polymerase I, a true DNA replicase, using the hybrid of phi X174 single-stranded DNA and a restriction endonuclease fragment as a template. It also increases processivity of DNA polymerase I at least 10-fold. Escherichia coli SSB, but not T4 gene 32 protein, can substitute for yeast SSB. Both restoration of DNA synthesis in the heated mutant cell extract and stimulation of the DNA polymerase I reaction by SSB from cdc8-1 cells are inactivated at nonpermissive temperatures, suggesting that yeast SSB is the CDC8 gene product.

Haloperidol causes irreversible damage to rat anterior pituitary lactotropes in culture

Haloperidol, in concentrations in excess of 10(-5)M promotes the release of prolactin from rat anterior pituitary cells in monolayer culture. Histologic evidence revealed that 10(-4)M concentrations cause an irreversible cytotoxic effect that resulted in a loss of cell membrane integrity and a massive release of intracellular prolactin into the surrounding medium. Paradoxically, at 10(-5)M, haloperidol significantly inhibited prolactin release and promoted an accumulation of intracellular secretory granules. Lower concentrations had no significant effect. Although it is nominally classified as a dopamine receptor blocker and can (in lower concentrations) inhibit dopamine's suppression of prolactin release, haloperidol in higher concentration enhances prolactin release by a cytotoxic mechanism unrelated to dopamine receptor interaction.

Measuring systolic arterial blood pressure. Possible errors from extension tubes or disposable transducer domes

The purpose of this study was to evaluate the magnitude of possible error in the measurement of systolic blood pressure if disposable, built-in diaphragm, transducer domes or long extension tubes between the patient and pressure transducer are used. Sinusoidal or arterial pressure patterns were generated with specially designed equipment. With a long extension tube or trapped air bubbles, the resonant frequency of the catheter system was reduced so that the arterial pulse was amplified as it acted on the transducer and, thus, gave an erroneously high systolic pressure measurement. The authors found this error to be as much as 20 mm Hg. Trapped air bubbles, not stopcocks or connections, per se, lead to poor fidelity. The utility of a continuous catheter flush system (Sorenson, Intraflow) to estimate the resonant frequency and degree of damping of a catheter-transducer system is described, as are possibly erroneous conclusions. Given a rough estimate of the resonant frequency of a catheter-transducer system and the magnitude of overshoot in response to a pulse, the authors present a table to predict the magnitude of probable error. These studies confirm the variability and unreliability of static calibration that may occur using some safety diaphragm domes and show that the system frequency response is decreased if air bubbles are trapped between the diaphragms. The authors conclude that regular procedures should be established to evaluate the accuracy of the pressure measuring systems in use, the transducer should be placed as close to the patient as possible, the air bubbles should be assiduously eliminated from the system.

Variable activity of disophenol against hookworms and lice of northern fur seal pups on St. Paul Island, Alaska

Six critical tests with disophenol were conducted in July, 1978, in fur seal pups (Callorhinus ursinus) naturally-infected with adult hookworms, Uncinaria lucasi, and infested with various stages of two species of sucking lice, Proechinopthirus fluctus (Ferris) and Antarctophthirus callorhini (Osborn). Disophenol at a dose rate of 12.5 mg/kg was administered subcutaneously to each of six pups. Each pup was contained in an individual cage for 60 h posttreatment at which time pups were exmained at necropsy. Efficacy against hookworms ranged from 2% to 88% and of both species of lice ranged from 26% to 90% for the six pups. Disophenol removed approximately 90% of all adult lice but only slightly more than 60% of all nymphs. The only sign of toxicosis was a probable drug related fluid-like feces for four pups from 12 to 60 h posttreatment.

Populations, microhabitat preference and effects of infestation of two species of Orthohalarachne (Halarachnidae: Acarina) in the northern fur seal

All of 116 northern fur seals examined, except black pups (up to 3 monts old), had nasal mites, Orthohalarachne attenuata and O. diminuata, with the mean density of 1,808 mites per subadult male, 435 per adult female, 251 per silver pup, and 21.5 per black pup. Only 63% of black pups examined were infested with both mites. Larvae represented as much as 99% of the total mite population (total samples), and the females of both species of Orthohalarachne accounted for more than 90% of the total population of adult mites. The O. attenuata adults inhabited the nasopharynx and O. diminuata adults were found primarily in the lungs. Larvae of both species occupied the mucus-filled turbinates. The heavy infestation with these mites appeared to result in impairment of respiration in fur seals, and could also cause lesions in the lungs and secondary alveolar emphysems, predispose to more serious diseases, or even kill the host animal.

Kilometer-path low-temperature multiple-reflection cell for laser spectroscopy using tunable semiconductor diodes

Design characteristics and performance are described for a low-temperature multiple-reflection cell used with a laser diode spectrometer. The optical pathlength can be varied from 0.04 km to 1.5 km in the temperature controlled cell from 160 K to 300 K. Examples are presented to illustrate pressure broadening in the 16 mum N(2)O band and to indicate some high resolution absorption measurements of rotational manifolds in the nu(4) band of SF(6) and an application to the analysis of the Q-branch of the 2nu(4)-nu(4) hot band transition in SF(6).

Chlorinated hydrocarbon and PCB residues in tissues and lice of northern fur seals, 1972

DDT, dieldrin, and PCB contents of tissues and the sucking lice of the northern fur seal (Callorhinus ursinus) were studied in samples collected in July 1972 in the Pribilof Islands, Alaska. They included the analyses of two nursing cows and their two newborn pups, three 2-month-old pups, and the sucking lice inhabiting these animals, Antarctophthirus callorhini and Proechinophthirus fluctus. The sigmaDDT content of fat tissue was 5.2, 5.6 and 63 mug/g (-/x) for cows, newborns, and 2-month-old pups, respectively. Dieldrin appeared at trace levels. PCB residues (Aroclor 1254) were 5.8, 5.5, and 33 mug/g (-/x), respectively. The sigmaDDT content of blood was less than 0.01 mug/g for cows and newborns and 4.6 mug/g for 2-month-old pups. PCB's were found only in trace amounts in the blood of all animals except one 2-month-old pup which contained 3.4 mug/g. Lice contained 0.2-6 percent, respectively, of the sigmaDDT and PCB's detected. All residues were expressed on a wet-weight basis. Two-month-old pups had far higher residue levels than had cows. A high percentage of sigmaDDT occurred as the DDE metabolite: 60 percent in cows and newborn pups and 90 percent in 2-month-old pups.

Taxonomy of Solenopotes Enderlein, 1904, with redescription of Linognathus panamensis Ewing (Linognathidae: Anoplura)

All the known species ofSolenopotesEnderlein, 1904 are discussed with a complete synonymy, major references, diagnoses, host associations and distribution; they areS. binipilosus(Fahrenholz, 1916a);S. burmeisteri(Fahrenholz, 1919);S. capillatusEnderlein, 1904;S. capreoliFreund, 1935a;S. ferrisi(Fahrenholz, 1919);S. muntiacusThompson, 1938;S. natalensisLedger, 1970 andS. tarandi(Mjöberg, 1915). The species ofSolenopotesare compared on the basis of major taxonomic characters.SolenopotesandLinognathusare compared and a key to the known species ofSolenopotesis also presented. Taxonomic relationships among the cervid-infesting species are quantitatively studied. The status ofLinognathus panamensisEwing, 1927, previously assigned toSolenopotes, is discussed and the species is redescribed and illustrated.

Rediscovery of Solenopotes tarandi (Mjöberg, 1915) (Linognathidae: Anoplura), with ectoparasites of the barren ground caribou

The adults ofSolenopotes tarandi(Mjöberg, 1915) are redescribed and illustrated, and its allied species ofSolenopotesare compared. The nymphs of this species are for the first time described and illustrated. Ectoparasite infestation of the barren ground caribou (Rangifer tarandus grantiAllen) is also discussed.