Search PubMed⌕ Search

Biomedical subjects

A Lee

Publications and source records attributed to A Lee.

At least 667 records · Page 37Linked to original sources
PubMed1989

Acute toxicity of ropivacaine compared with that of bupivacaine.

The acute central nervous and cardiovascular effects of the local anesthetics ropivacaine and bupivacaine were compared in 12 volunteers in a randomized double-blind manner with use of intravenous infusions at a rate of 10 mg/min up to a maximal dose of 150 mg. The volunteers were all healthy men. They were familiarized with the central nervous system (CNS) toxic effects of local anesthetics by receiving a preliminary intravenous injection of lidocaine. The infusions of ropivacaine and bupivacaine were given not less than 7 days apart. CNS toxicity was identified by the CNS symptoms and the volunteers were told to request that the infusion be stopped when they felt definite but not severe symptoms of toxicity such as numbness of the mouth, lightheadedness, and tinnitus. In the absence of definite symptoms, the infusion was stopped after 150 mg had been given. Cardiovascular system (CVS) changes in conductivity and myocardial contractility were monitored using an interpretive electrocardiograph (which measured PR interval, QRS duration, and QT interval corrected for heart rate) and echocardiography (which measured left ventricular dimensions from which stroke volume and ejection fraction were calculated). Ropivacaine caused less CNS symptoms and was at least 25% less toxic than bupivacaine in regard to the dose tolerated. Both drugs increased heart rate and arterial pressure. Stroke volume and ejection fraction were reduced. There was no change in cardiac output. Although both drugs caused evidence of depression of conductivity and contractility, these appeared at lower dosage and lower plasma concentrations with bupivacaine than with ropivacaine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Gastric campylobacter-like organisms: their role in gastric disease of laboratory animals.

Campylobacter pylori, first isolated in 1982, is now recognized as a primary cause of acute gastritis in man, and there is substantial data suggesting that this organism also plays an important role in the pathogenesis of duodenal ulcers. More recently, Campylobacter-like organisms and other morphologically distinct spiral bacteria have been isolated from gastric lesions in a variety of laboratory animal species. The zoonotic significance of C. pylori and other gastric spiral bacteria isolated from man as well as laboratory and domestic animals requires further study. An appreciation of the ecological and pathological role of gastric spiral bacteria in domestic and laboratory animals is an essential first step when considering the role and proper selection of animal models in the study of C. pylori gastroduodenal disease.

Animals↗
PubMed1989

Cochlear implant hearing performance at the University of Minnesota.

The hearing performance of six post-lingually deaf adults implanted with the Nucleus 22-channel device are presented. All patients achieved measurable open set speech recognition with implant alone. The best hearing performance was achieved with a combination of lipreading and cochlear implant. For this condition our group achieved an average open set speech discrimination score of 85% (CID sentences) and an average speech tracking rate of 70 words per minute. We attribute the success of our group to careful pre-operative selection, including attention to candidate motivation toward hearing rehabilitation.

Adult↗
PubMed1988

A new type of transforming growth factor-beta, TGF-beta 3.

A new type of TGF-beta, TGF-beta 3, has been identified by cDNA characterization. The amino acid sequence of mature TGF-beta 3 and its precursor has been derived from porcine and human cDNA sequences. The human TGF-beta 3 gene is spread over seven exons as in the case of the TGF-beta 1 gene. Comparison with TGF-beta 1 and -beta 2 indicates a strong conservation of the mature sequences, but a relaxed homology in the precursor segments. TGF-beta 3 mRNA is mainly expressed in cell lines from mesenchymal origin, suggesting a biological role different from the other TGFs-beta.

Amino Acid Sequence↗
PubMed1988

Differential expression of cellular oncogenes during rat liver development.

The expression of a number of proto-oncogenes (myc, erb B, Ha-ras, bas, rel, mos, sis, myb, ki-ras, fms, src and fos) was studied in developing rat liver. Northern blot hybridization shows that cellular counterpart of erb B, Ha-ras, and fos oncogenes were in an early stage of liver development, and the expressions of these proto-oncogenes gradually decreased as the liver developed, while c-myc transcript was found only in the rat fetal liver. The transcripts of these oncogenes were found in high level in Morris hepatoma 7777. Bas proto-oncogene was found in high expression at early stages of rat liver development but was not in hepatoma 7777. The expression of other proto-oncogenes studied (src, fm, rel, mos, sis, myb and ki-ras) did not change significantly during liver development and was almost the same in hepatoma and normal adult liver. Southern blot analysis demonstrates that gene amplification and apparent gene rearrangement were not responsible for the change in expression of erb B, Ha-ras, myc and fos proto-oncogenes. Our study gives further evidence that erb B, myc, Ha-ras and fos proto-oncogenes are involved in the control of cell growth and in the process of rat hepatocarcinogenesis.

Aging↗
PubMed1988

Regulatory activity of the human CD8+ cell subset: a comparison of CD8+ cells from the intestinal lamina propria and blood.

This study was done to better define the immunoregulatory mechanisms in the human intestinal lamina propria (LP). Peripheral blood (PB) and LP cells were obtained from patients having intestinal resections. CD4+ and CD8+ cell subsets were isolated using hybridoma antibodies in a panning technique. Graded numbers of LP and PB CD8+ cells were added to cultures of autologous fresh B cells plus CD4+ cells plus pokeweed mitogen. After 10 days incubation in vitro, the supernatants were collected, and IgM and IgA synthesis was measured by isotype-specific sandwich ELISA. Both PB and LP CD8+ cells suppressed IgM and IgA synthesis by indicator cultures consisting of 5 X 10(4) B cells plus 5 X 10(4) CD4+ cells to a comparable extent. However, when these same CD8+ cells were added to indicator cultures of 5 X 10(4) B cells plus 10(5) CD4+ cells, PB CD8+ cells still suppressed, but LP CD8+ cells enhanced IgM and IgA synthesis. LP but not PB CD8+ cells also augmented IgM and IgA synthesis in cultures with suboptimal immunoglobulin synthesis. Despite these results, LP CD8+ cells were not able to provide help for B cell immunoglobulin synthesis when these two cell types were cultured together with pokeweed mitogen. The mechanism of immunoglobulin augmentation by LP CD8+ cells appeared to involve antagonism of a CD4+ rather than CD8+ suppressor cells. We conclude that functional heterogeneity is more evident within the LP CD8+ subset, with both suppressor and contra-suppressor activities demonstrable, with the latter representing a major activity in LP but not in PB CD8+ cells.

Antigens, Differentiation↗
PubMed1988

Women in search of stability.

This paper is based on a study of 97 recruits--50 sterilized and 47 non-sterilized--to a family planning programme in Kingston, Jamaica and tries to account for the reluctance of Jamaican women to accept contraceptive sterilization. The study demonstrates the association between mating patterns in the island and the acceptance of sterilization. This irreversible method was more likely to be chosen by women in more stable sexual unions.

Adult↗
PubMed1988

Emotion recognition in autism: coordinating faces and voices.

Autistic and non-autistic mentally retarded adolescents and young adults were individually matched for age and verbal ability and were given tasks in which they chose photographs of faces for emotionally expressive voices, and photographs of non-emotional things or events to accompany recorded sounds. The results were that relative to control subjects, autistic individuals performed less well on the emotion tasks than on the non-emotion tasks. The findings suggest that autistic individuals have a disability in recognizing bodily expressions of emotion, and that there is a degree of task-specificity to this impairment.

Adolescent↗
PubMed1988

Experimental colonization of broiler chicks with Campylobacter jejuni.

Minimal colonization inocula for two broiler strains of Campylobacter jejuni were determined in broiler chicks aged 2-3 days and 2 weeks. Individually housed chicks were exposed to a single oral or cloacal challenge. Diarrhoeal symptoms were absent in all 380 chicks included in the study. Chick susceptibility to the two C. jejuni strains varied. Colonization was effected by less than 10(2)-10(4) colony forming units (c.f.u.) via cloacal challenge and 10(4)-10(6) c.f.u. via the oral route. Colonization inocula for 2- to 3-day and 2-week-old chicks were similar. Treatment of 1-day-old chicks with fresh adult caecal flora or an anaerobic broth culture of adult caecal flora did not inhibit colonization after challenge with low-dose C. jejuni. Susceptible chicks were colonized rapidly. C. jejuni was detected in 167 of 189 (88%) colonized chicks within 3 days of challenge and persisted during the 2-week monitoring period. Our data suggest that colonization of broiler chicks with C. jejuni is effected more easily by the cloacal than the oral route and is independent of age.

Animals↗
PubMed1988

Postoperative analgesia by continuous extradural infusion of bupivacaine and diamorphine.

Three solutions administered by continuous extradural infusion for postoperative analgesia were compared in a randomized, double-blind manner. All patients underwent major abdominal gynaecological surgery and received 0.125% bupivacaine in 0.9% saline, diamorphine in 0.9% saline (0.5 mg in 15 ml) or diamorphine mixed with 0.125% bupivacaine (0.5 mg in 15 ml), at a rate of 15 ml h-1. The bupivacaine-diamorphine mixture provided significantly superior analgesia compared with either bupivacaine or diamorphine alone. No major side effects were encountered.

Abdomen↗
PubMed1988

Effect of dextrose concentration on the intrathecal spread of amethocaine.

Effects of solutions of 0.5% amethocaine, containing different concentrations of dextrose (0%, 1.25%, 2.5% and 5%) were studied after intrathecal injection. The cephalad extent of block was greater with all three dextrose-containing solutions (T6), compared with the isobaric solution which contained no dextrose (T11). The variability of maximum level of block within each group was similar (seven dermatomes), and the rate of onset to maximum extent of block was the same in all groups. The rate of onset to the T12 dermatome was more rapid in the patients who received solutions containing dextrose. The initial onset of effect of the solution containing 1.25% dextrose was more like that of the isobaric solution than of those containing higher concentrations of dextrose.

Adolescent↗
PubMed1988

Tolerance and rebound during and after short-term administration of quazepam, triazolam and placebo to healthy human volunteers.

Quazepam 15 mg, triazolam 0.25 mg and placebo were administered to 12 healthy volunteers. Each drug was given for 14 nights using a balanced design with at least 28 days between drug administrations. A test battery of physiological, psychological and subjective measures was administered on the mornings of days 1, 8, 14, 15 and 22 of the drug and post-drug periods. Seven days prior to and on days 1 to 28 of the drug and post-drug periods, sleep and self evaluation questionnaires were completed. Quazepam was associated with definite EEG effects, an unexpected improvement in simple motor performance and an increase in several bodily symptoms and ratings of sedation. Triazolam-impaired performance and also increased ratings of bodily symptoms and sedation. Two symptom increases with triazolam--metallic taste and touch sensitivity--might reflect day-time rebound. Sleep quality was improved by both drugs. There was little evidence of tolerance to drug effects on EEG or psychomotor tests. However tolerance was seen to the bodily symptoms and mood ratings. Rebound after drug discontinuation was not convincingly detected.

Adult↗
PubMed1988

Motility of Campylobacter jejuni in a viscous environment: comparison with conventional rod-shaped bacteria.

The motility of four strains of Campylobacter jejuni in solutions of varying viscosity was measured and compared to that of a number of conventional rod-shaped bacteria (CRSB). All the bacteria tested showed an initial increase in velocity in the low viscosity solutions--between 1 and 3 centipoise (1 P = 0.1 Pa s). However, only the campylobacters were actively motile in highly viscous solutions with velocities ranging from 60 to 100 micron s-1. All strains of C. jejuni tested showed three separate peaks of motility as the viscosity of the solution was increased. A higher proportion of C. jejuni cells exhibited longer path lengths when the viscosity of the surrounding medium was increased from 1.4 to 57 cP. The findings of the study suggest that C. jejuni has a motility suited to movement in a viscous environment, and that this ability might provide the organism with an ecological advantage when in intestinal mucus. It is proposed that the mechanism of motility changes depending on the viscosity of the supporting environment.

Campylobacter fetus↗
PubMed1988

The urease enzymes of Campylobacter pylori and a related bacterium.

The urease enzyme of Campylobacter pylori was studied and compared with that of a related spiral-shaped bacterium, St1, isolated from the rodent ileum. Both bacteria possessed constitutive urease enzymes with activities up to 20-70 times that of Proteus vulgaris. This activity was retained on SDS-polyacrylamide gels. A major catalytic subunit of mol. wt 300,000 was located for all (six) strains of C. pylori subjected to SDS-PAGE whereas St1 had two active forms of mol. wts 140,000 and 150,000. Western-blot analysis indicated the presence of anti-urease antibodies in the sera of patients with C. pylori-associated gastritis. The response to C. pylori urease was not strain-specific but no cross-reactivity was detected between the C. pylori enzyme and that of St1. The very high urease activity of these bacteria is likely to be important in colonisation of the host. Possession of glutamate dehydrogenase activity by both organisms suggests that one role of the urease may be to assimilate the available urea nitrogen. Modification of the local environment to facilitate long-term colonisation is another possible function. Protection from acid is unlikely to be a primary role as the natural habitat of the organism St1 is the non-acid-secreting tissue of the small intestine.

Ammonia↗
PubMed1988

What's in a face? The case of autism.

Groups of verbal MA-matched autistic and non-autistic retarded adolescents and young adults were tested for their ability to recognize emotion and personal identity in photographed faces and parts of faces. The tasks were to match expressions of emotion across different individuals, and to identify unfamiliar individuals despite changes in emotional expression. Faces were also presented upside-down. The results indicated a specific abnormality in the way autistic individuals perceive emotion, and possibly sex, in people's faces. In addition, however, autistic subjects' superior ability in matching upside-down faces suggested a more far-reaching abnormality in their perception of faces.

Adolescent↗
PubMed1988

Isolation of a spiral-shaped bacterium from the cat stomach.

A spiral- or helix-shaped bacterium that colonizes the stomachs of cats has been isolated in pure culture for the first time. The organism is tightly coiled with tufts of 10 to 17 polar flagella positioned slightly off center at the end of the cell. The body of the cell is entwined with unique periplasmic fibrils that usually occur in pairs, although groupings of one and three fibrils were also seen. The organism is strongly urease, catalase, and oxidase positive and is likely to belong to an as yet unclassified group of bacteria that are specifically adapted to the ecological niche provided by gastrointestinal mucus. Isolation of this organism will allow study of the factors influencing colonization of gastric mucosae, information relevant to the association of another mucus colonizer, Campylobacter pylori, with the human stomach. Recent reports of the isolation of other bacteria with the characteristic periplasmic surface structures suggests that the group may be more widespread than was hitherto thought. Bacteria with the morphology of the organisms seen in the cat stomach have been seen in gastric biopsies from humans. The organism whose isolation is reported here has been used in previous serological studies to support the hypothesis that spiral bacteria from animals can colonize the human stomach.

Animals↗