PubMed Health⌕ Search

Biomedical subjects

A Lui

Publications and source records attributed to A Lui.

11 recordsLinked to original sources
PubMed1991

Elective oral tracheal intubation in cervical spine-injured adults.

There is controversy regarding the optimal mode of elective tracheal intubation in the patient with an unstable cervical spine following trauma. A ten-year review of 150 patients with traumatic cervical spine injuries with well-preserved neurological function, presenting for operative stabilization, was conducted to compare neurological outcome with the mode of tracheal intubation. Preoperative neurological deficits were identified in 49 patients (33%); most were single-level radiculopathies. Intubation occurred after induction of general anaesthesia in 83 patients (55%) and in 67 patients (45%) the tracheas were intubated with the patient awake. One hundred and six patients (71%) underwent oral tracheal intubation and 44 underwent nasal tracheal intubation. Ten intubations were deemed to be difficult requiring more than one attempt to effect intubation. Cervical spine immobilization during intubation was documented in 86 patients (57%). Weighted traction or manual in-line traction were the two manoeuvres most commonly employed to maintain spinal alignment during intubation. After surgery, two patients had new neurological deficits. There were no differences in neurological outcome whether intubation was performed while the patient was awake or under general anaesthesia, or comparing oral tracheal intubation with all other techniques (P = 0.5, Fisher exact test). Also, in-line traction did not affect neurological outcome. Oral tracheal intubation with in-line stabilization, either performed after induction of general anaesthesia or with the patient awake, remains an excellent option for elective airway management in patients with cervical spine injuries.

Adolescent↗
PubMed1991

Endogenous opioids are involved in the genetically determined high preference for ethanol consumption.

The link between endogenous opioid peptides and the genetic predisposition to preferentially consume ethanol was examined in alcohol preferring C57BL/6J mice compared with the alcohol nonpreferring DBA/2 mice. Concentrations of Met-enkephalin pentapeptide or precursor in various brain regions of potential relevance were not different between the two strains. C57BL/6J mice had a significantly lower pain threshold that could be increased by a selective mu-receptor opioid agonist [D-Ala2, MePhe4, Met(O)5-ol]-enkephalin. Treatment with this drug also decreased ethanol consumption in C57BL/6J mice. Increasing the synaptic half-life of endogenous enkephalins by the enkephalinase inhibitor kelatorphan also decreased ethanol consumption. Assay of endogenous enkephalin degrading activity showed increased enkephalinase activity in striatal issue of C57BL/6J compared with DBA/2 tissue. These results suggest that a relative lack of enkephalin peptides trans-synaptically, possibly resulting from enhanced enkephalin degradation may contribute to increase alcohol consumption in C57BL/6J mice.

Alcohol Drinking↗
PubMed1991

Effect of insecticides (Dimiline WP 25, Torak EC 24 and Gamacide 20) on hydra (Hydra vulgaris Pallas).

Investigations showed that the three insecticides used had the most damaging effect upon hydra immediately after treatment. The tentacles and the hypostome are the parts most often damaged. Inse the affected cells, lesions appear in the intracellular membranes, the nucleus shell and the membranes of the mitochondria, Golgi complex and the endoplasmic reticulum, while the cell membrane is preserved. The damaged parts of the body regenerate within three days. Zymogen cells play a significant role in the course of regeneration. They dedifferentiate into gastrodermal interstitial cells and later into other types of cells of the ectoderm and the gastroderm. Apart from their intense participation in regeneration, these totipotent cells also invariably participate in the formation of new hydra buds. It was observed that Dimiline WP 25 and Torak EC 24 in the concentrations used stimulate asexual reproduction of this animal.

Animals↗
PubMed1990

Structures of paralytic acylpolyamines from the spider Agelenopsis aperta.

The structures are given for five paralytic acylpolyamines from the venom of the funnel web spider, Agelenopsis aperta. The acyl moieties are derived from (3-indolyl)acetic acid, (4-hydroxy-3-indolyl)acetic acid, and 4-hydroxybenzoic acid. The polyamine portions of the toxins are novel. Three toxins (AG489, AG505, and AG452) contain 1, 5, 9, 13, 18, 22-hexaazadocosane which is unique as a natural polyamine because of its length and hydroxylation at the 5-aza position. The polyamine portions of two other alpha-agatoxins (AG488 and AG504) are unusual also, containing guanidinooxy moieties.

Animals↗
PubMed1990

The adult cervical spine: implications for airway management.

Anaesthetists are responsible for the management of the airway in patients with unstable cervical spines. Unfortunately, the anaesthetic literature does not contain a recent, critical analysis of the current medical literature to aid anaesthetists attending such patients. This review is intended to serve such a purpose. Using the Index Medicus as a guide, 30 years of medical literature were reviewed, with emphasis on the last ten years. Key words employed for this review are cited in the manuscript. Relevant papers were selected from anaesthetic, orthopaedic, rheumatologic, emergency medicine and trauma journals and reviewed. Relevant findings included the high prevalence of cervical spinal instability in such disorders such as Trisomy 21 and rheumatoid arthritis and the relatively low incidence after trauma. There are deficiencies in the minimalist approaches to assessing the cervical spine, such as a simple cross table lateral radiograph after trauma, as they are neither sensitive nor specific. Finally, recognizing the potential for instability and intubating with care, while avoiding spinal movement, appears to be more important than any particular mode of intubation in preserving neurological function.

Adult↗
PubMed1990

Chemical characterization of acylpolyamine toxins from venom of a trap-door spider and two tarantulas.

Two acylpolyamines are identified from venom of the trap-door spider, Hebestatis theveniti. These toxins (paralytic to lepidopteran insect larvae) are amides containing 3-(3-indolyl)lactic acid joined to spermine or 1,13-diamino-4,10-diazatridecane (Het389 and Het403, respectively). Het389 is also abundant in venom from a tarantual from Mozambique (Harpactirella sp.). Two additional acylpolyamines (Apc600 and Apc728) are partially characterized from venom of another tarantula, Aphonopelma chalcodes.

Animals↗
PubMed1977

5-O-beta-D-Galactofuranosyl-containing exocellular glycopeptide of Penicillium charlesii. Incorporation of mannose from GPD-D-mannose into glycopeptide.

Three-day-old Penicillium charlesii mycelia were broken with Al2O3 in a buffered system and the membranes were separated on a linear gradient of sucrose concentrations. The most active guanosine 5'-(alpha-D-mannopyranosyl pyrophosphate):glycopeptide mannopyranosyltransferase (GPD-D-mannose mannosyltransferase) was found in two unresolved membrane fractions ( p congruent to 1.1 g/cm3). This preparation incorporated [14C]mannose from GDP-D-[14C]mannose both into endogenous acceptors and added peptidophosphogalactomannan. Mannosyltransferase activity is optimum at pH 7.0 in 0.05 M Tris/maleate buffer, and 17 mM Mn2+. Replacement of Mn2+ with Fe2+, Mg2, Co2+, Ca2+ or Ni2+ greatly reduced the mannosyltransferase activity. [14C]Mannose incorporation from GDP-D-[14C]mannose into acceptors is linearly dependent on enzyme concentration. Mannosyl incorporation into peptidophosphogalactomannan is linear for 3 h and continues for at least an additional 4 h. In contrast, the rate of mannosyl incorporation into endogenous acceptor(s) decreases after 60 min and there is no incorporation after 2 h. A series of possible acceptors related to peptidophosphogalactomannan were tested and it was found that treatment of peptidophosphogalactomannan with 0.01 N HCl at 100 degrees did not appreciably decrease the effectiveness of the acceptor even though this treatment removes the galactofuranosyl residues. In contrast, treatment of peptidophosphogalactomannan with 0.5 N NaOH rendered the products nearly incapable of accepting mannosyl residues from GDP-D-mannose. Derivation of peptidophosphogalactomannan with 2,4-dinitrobenzene also decreased its effectiveness as a mannosyl acceptor. [14C]Mannose from GDP-D-[14C]mannose was incorporated into both the oligosaccharide and phosphogalactomannan regions of peptidophosphogalactomannan. Treatment of the [14C]peptidophosphogalactomannan product, with 0.4 N NaOH released [14C]mannosyl-containing residues which eluted in the mannobiose and polysaccharide fractions from BIo-Gel P2. Approximately 90% of the 14C was in mannobiose. The [14C]mannose was shown to be transferred to the mannosyl-(seryl/threonyl) region of the acceptor. Acetolysis of [14C]peptidophosphogalactomannan resulted in the isolation of [14C]mannose, [14C]mannobiose, and [14C]polysaccharide. Small quantities of 14C were obtained in mannotriose and mannotetraose. The time course of [14C]mannose incorporation into the oligosaccharide region of peptidophosphogalactomannan showed a continual increase over a 4-h interval. In contrast, there was no major increase after 1 h in [14C]mannose incorporated into the polysaccharide region. The enzyme catalyzing incorporation of mannose into the polysaccharide region of peptidophosphogalactomannan was solubilized by treatment of the membranes with Triton X-100.

Cations, Divalent↗
PubMed1977

Regeneration of proximal and distal part of hydra body cut in the middle of gastral cavity and treated with dactinomycine.

Hydras were cut in the middle of the gastral part of the body. The part with the hypostome is marked as H, and the one with the foot as P. Both parts were treated with actinomycine D in 0,5 mg : 200 ml water solution. H-parts are much more sensitive to the effect of actinomycine than P-parts, and P lives considerably longer. It is supposed that such reaction are the result of specificity of H and P cell composition, and of the growth direction which is characteristic of hydra in general. H-part has a proportionally greater number of differentiated cells and this relatively smaller number of non-differentiated cells is spent in it quicker than in P-part in which they are more numerous. The growth direction has a decisive influence on further life of H- respectively P-part. Namely, H- in growth direction does not have any damaged body regions (hypostome and tentacles are intact) and it lacks the amputated P-part i.e. gastral region with foot: the region which is on the opposite side of growth direction of hydra. H-part has all the characteristic cells of this body region, so after amputation mostly it does not change. Unfavourable effect of citostatic manifests sooner and H-part desintegrates quicker. On the contrary, P-part lacks the hypostome with tentacles, and these are the body parts in the growth direction. Zimogen cells can dedifferentiate and differentiate. The hypostome and tentacles regenerate as far as is allowed by actinomycine.

Animals↗
PubMed1976

Effects of dactinomycine (actinomycine D) on budless hydra and during its budding process.

The effect of dactinomycine (actinomycine D) is manifested in various ways, which depends upon its concentration and animal condition at the time of treatment. Dactinomycine is citotoxic in stronger concentations so hydra dies quickly. In thinner concentrations it stops the mitotic activity of the cell, but the basic metabolic processes continue as before. Interstitial cells differenciate into cnidoblasts for some time, the cnid production is not halted, but all of these cells disappear as well as zimogen cells which dedifferentiate into gastrodermal interstitial and into mucous cells. Such animals live longer but die eventually. The effect of dactinomycine is generally milder on animals with a larger cell mass, in hydras with the budding tendency where exist such reserves and in those hydras in which the budding process has begun. In these a part of mobile undamaged zimogen cells can remain. They keep their reproduction ability. These animals can survive and keep on growing normally.

Animals↗
PubMed1976

The effect of levamisole on cell-mediated immunity and suppressor cell function.

The immunopotentiating drug, levamisole, was found to augment human lymphocyte responses to allogeneic cells and plant mitogens in vitro. The effect was critically dose dependent and, at high doses, suppression rather than augmentation of the immune response was observed. Our hypothesis that augmentation of immune responses by the drug is due to the selective impairment of immunoregulatory suppressor activity was tested in a model using human splenic and thymic suppressor cells. Contrary to expectation, the drug was found to be capable of augmenting suppressor activity rather than abolishing it. It is concluded that levamisole is a nonspecific stimulator of lymphocyte function, irrespective of the role played by these cells in the human response.

Dose-Response Relationship, Drug↗