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Biomedical subjects

C E Smith

Publications and source records attributed to C E Smith.

At least 199 records · Page 11Linked to original sources
PubMed1989

Metacercariae of Diplostomum spathaceum in the eyes of fishes from Yellowstone Lake, Wyoming.

Fish were collected from Yellowstone Lake, Wyoming (USA). Metacercariae of Diplostomum spathaceum was found in the lens of 11 of 12 longnose suckers (Catostomus catostomus). The mean number of metacercariae per sucker was 59 and the average age of the fish was 11.6 yr. There was no correlation between age and intensity of parasites (r = 0.24). Of 10 cutthroat trout (Salmo clarki) examined, there were metacercariae present in six. The metacercariae were found outside of the lens tissue in the trout; they occurred in the vitreous humor and the retina. These may be a different species from those found in the suckers.

Animals↗
PubMed1989

Secretory activity as a function of the development and maturation of ameloblasts.

The biosynthetic and secretory activity of rat incisor ameloblasts was studied by grain count analysis of radioautographs at various times following a single injection of either 3H-methionine, 3H-leucine, or 3H-glycine. Experiments were also carried out with leupeptin, a thiol and serine proteinase inhibitor which blocks degradation of proteins within lysosomes. The results from this study indicate that the biosynthetic and secretory activities of ameloblasts increase steadily as the cells differentiate (presecretory stage) and start to form the enamel layer (secretory stage). Secretory activity reaches a peak when the ameloblasts form about one-third of the eventual thickness of the enamel, and remains at this high level until shortly before they start to form the outer and final layers of enamel. Secretory activity then drops rapidly as the cells undergo postsecretory transition, and declines slowly thereafter as the shortened ameloblasts modulate continuously along the surface of the maturing enamel. Ameloblasts appear to biosynthesize more proteins than are secreted. The excess proteins are degraded rapidly in lysosomes and the amino acids reutilized for production of new exportable and/or structural proteins.

Ameloblasts↗
PubMed1989

Effects of succinylcholine at the masseter and adductor pollicis muscles in adults.

The effect of succinylcholine on baseline tension and evoked twitch height was measured at the masseter and the adductor pollicis muscles in ten adults undergoing elective surgery. During thiopental-nitrous oxide-enflurane (end-tidal concentration less than 0.25%) anesthesia, supramaximal stimulation was applied to both the ulnar nerve and the nerve to the masseter. Baseline tension and the isometric force of contraction were measured at the jaw and the thumb. Cumulative dose-response relationships were obtained by giving succinylcholine in incremental doses (initial dose, 0.10 mg/kg, followed by 0.05- or 0.1-mg/kg increments, depending on response). An infusion was started after the maximum effect of the first dose, at a rate adjusted to compensate for the rapid metabolism of the drug. There was no difference between the sensitivity of the masseter and the adductor pollicis. The ED50 values were (mean +/- SEM) 0.11 +/- 0.01 mg/kg at both muscles. The ED90 values were 0.17 +/- 0.02 mg/kg at the masseter and 0.16 +/- 0.01 mg/kg at the adductor pollicis. Onset of action was more rapid at the masseter. In six of the ten patients, baseline tension at the jaw was found to increase by a mean of 80 +/- 24 g (range 25-188 g). It is concluded that in adults, masseter neuromuscular blockade can be achieved with succinylcholine doses approximately equal to those required to block the adductor pollicis. In addition, the drug may cause increased tension in the muscles of the jaw.

Adult↗
PubMed1989

Overview of patient education. Opportunities and challenges for the twenty-first century.

Nurses, on a day-to-day basis, and the profession as a whole, will continue to be challenged by the economic climate and nursing shortage. Nursing must march forward, demonstrating the ability to delivery cost-effective patient education based on research. Issues in patient education must be addressed by the profession as a whole. Benefits of education, resulting from nursing care, for patients, families, and communities, as outlined in this overview, must be brought to the public's attention. In this way the opportunities for the twenty-first century will be achieved and the challenges met.

Forecasting↗
PubMed1989

Dose-response relationships for edrophonium and neostigmine as antagonists of moderate and profound atracurium blockade.

To measure the ability of neostigmine and edrophonium to reverse moderate and profound atracurium blockade, dose-response relationships were established for these reversal agents given at 1% and 10% twitch height recovery. Eighty-five ASA I and II adult patients received atracurium, 0.4 mg/kg, during a thiopental-nitrous oxide-enflurane anesthetic. Train-of-four stimulation was applied every 12 seconds, and the force of contraction of the adductor pollicis muscle was recorded. Edrophonium, 0.1, 0.2, 0.4, or 1 mg/kg; neostigmine, 0.005, 0.01, 0.02 or 0.05 mg/kg; or no reversal agent was given when there was either 1% or 10% recovery of the first twitch response. With profound blockade, the slope of the edrophonium dose-response relationship was significantly flatter (P less than 0.05) than that of neostigmine. The dose of neostigmine required to achieve 80% first twitch recovery (ED80) after 10 minutes was 0.013 +/- 0.003 mg/kg (mean +/- SEM) if given at 10% recovery, and 0.032 +/- 0.004 mg/kg if given at 1% recovery. The ED80 for edrophonium was 0.22 +/- 0.04 mg/kg and 1.14 +/- 0.33 mg/kg, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 16.6 +/- 3.5 and 35.3 +/- 8.9 at 90% and 99% blockade respectively (P less than 0.006). We conclude that the relative potency of neostigmine is greater than that of edrophonium for antagonism of profound atracurium blockade.

Atracurium↗
PubMed1988

Expression of secreted insulin-like growth factor-1 in Escherichia coli.

The synthesis, processing and secretion of insulin-like growth factor-1 (IGF-1 or somatomedin-C) fused to LamB and OmpF secretion leader sequences in Escherichia coli have been investigated. Expression and secretion of IGF-1 was achieved. The major portion of this secreted IGF-1 accumulated in the periplasmic space as insoluble aggregates. A small amount of IGF-1 was found folded in its native conformation in the medium. The lamB and ompF signal sequences were fused to the 5' coding sequence of IGF-1. Fusion of the lamB signal sequence directly to IGF-1 (lamB-IGF-1) resulted in accumulation of 16-20 micrograms/A550/ml of correctly processed IGF-1 in the periplasmic space. The processing efficiency of LamB-IGF-1 and OmpF-IGF-1 was enhanced in an E. coli strain bearing a prlA4 mutation. Amino acid sequence analysis of IGF-1 secreted into the periplasm and exported into the medium confirmed the precise removal of the LamB or OmpF signal sequence. IGF-1 synthesized in E. coli was demonstrated to be active in a cell proliferation bioassay.

Amino Acid Sequence↗
PubMed1988

Effectiveness of neonatal transport in New York City in neonates less than 2500 grams--a population study.

In the past two decades, there has been a gradual trend to regionalization of perinatal care, categorization of hospitals and transport services for neonatal health care. The literature alludes to both beneficial and deleterious effects of neonatal transport (T) but no controls such as a matched nontransport (NT) population have been utilized to date. The major goal of this study was to evaluate the effect of neonatal transport from Level I and II high risk less than or equal to 2500 gm. neonates (born in NYC in one calendar year, 1979) compared to a cohort nontransported population matched for hospital of birth, weight, race, sex and risk. All transported less than or equal to 2500 gm. from Level I and II (n = 328) were studied and a stratified random sample of the nontransported (NT) infants less than or equal to 2500 gm. from these same hospitals (n = 2042) was used for comparison. The principle outcome variable was survival. The major conclusion of this study is that in Level I and II hospitals the transport group had a significantly increased survival in infants who were sick (Apgar less than 6) compared to cohorted nontransported controls. Interhospital differences in survival were noted among Level I and II but not seen in the subdivisions of (A) and (B) hospitals.

Demography↗
PubMed1988

Postoperative vomiting following strabismus surgery in paediatric outpatients: spontaneous versus controlled ventilation.

The study was designed to compare the frequency and severity of postoperative vomiting in paediatric out-patients receiving controlled ventilation (IPPV) or breathing spontaneously (SV) during anaesthesia for strabismus repair. One hundred and twenty unpremedicated children (ages 2-12 years) were studied in a randomized fashion. After intravenous induction of anaesthesia and tracheal intubation, patients breathed halothane 1-1.5 per cent inspired and N2O 66 per cent in O2 spontaneously (n = 60), or received IPPV, halothane 0.5-1 per cent, N2O 66 per cent, and pancuronium 0.05 mg.kg-1, which was reversed with neostigmine and atropine (n = 60). The incidence of vomiting with SV was 50 per cent (95 per cent confidence limits: 34.5-65.5 per cent) compared with 40 per cent (24.5-55.5 per cent) with IPPV (p greater than 0.25). Patients in the SV group experiencing emesis had longer operations than those not vomiting (mean +/- SEM = 1.5 +/- 0.1 vs 1.2 +/- 0.1 hours, p less than 0.005). This was not the case with IPPV. There was no correlation between age, sex, duration of surgery, or number of extraocular muscles repaired, and frequency or severity of vomiting or time to discharge. No significant advantage was afforded by IPPV over SV in the present study.

Child↗
PubMed1988

Intravenous meperidine for control of shivering during caesarean section under epidural anaesthesia.

To determine the efficacy of meperidine in controlling shivering during epidural anaesthesia for Caesarean section, forty-six parturients were studied. After delivery of the infant, shivering patients received either a single dose of intravenous meperidine 50 mg, or saline in a randomized double-blind fashion. Shivering was classified on a scale of 0 to 3 (grade 0 = none, grade 3 = severe shivering that was distressing to the patient and interfered with monitoring). Shivering and other variables were recorded at epidural placement, skin incision, delivery, and 2, 5, 15, 30 and 60 minutes following injection. Administration of meperidine resulted in a significant decrease in both the overall incidence of shivering (87 to 35 per cent, p less than 0.01) and severity of shivering (grade 3:57 to 0 per cent, p less than 0.01), compared with saline (incidence: 87 to 83 per cent, grade 3:57 per cent, no change). This effect was apparent within two minutes of drug injection and persisted throughout the study period. There were no differences in vital signs, oxygen saturation or temperature between groups. The incidence of nausea was similar, although patients receiving meperidine were more drowsy at two and five minutes following injection (p less than 0.01) compared with patients in the saline group. There were no differences in level of consciousness at the later intervals. The mechanism of action of meperidine on shivering remains to be elucidated.

Adult↗
PubMed1988

Arginine chemical modification of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase.

Reaction of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS) with the arginine reagents phenylglyoxal (PGO) and p-hydroxyphenylglyoxal (HPGO) leads to inactivation of the enzyme. Inactivation with HPGO leads to modification of approximately 3 mol of arginine per mole of enzyme. The modification reaction follows pseudo-first-order kinetics with a t1/2 of 1 min at 5 mM p-hydroxyphenylglyoxal in 0.1 M triethanolamine HCl, pH 7.8. By titration of HPGO-modified enzyme with 5,5'-bis(dithio-2-nitrobenzoic acid), the possibility of cysteine modification by the arginine reagent was ruled out. While shikimate 3-phosphate (S3P) afforded partial protection to the enzyme against inactivation by HPGO, complete protection could be obtained by using a mixture of S3P and glyphosate. Under the latter conditions, only 1 mol arginine was modified per mole of enzyme. This pattern of reactivity suggests that two arginines may be involved in the binding of S3P and glyphosate to EPSP synthase. A third reactive arginine appears to be nonessential for EPSPS activity. Labeling of EPSP synthase with [14C]phenylglyoxal, peptic digestion, HPLC mapping, and amino acid sequencing indicate that Arg-28 and Arg-131 are two of the reactive arginines labeled with [14C]PGO.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1988

Bronchial leukocyte proteinase inhibitor: hydrodynamic properties and interaction with alpha 2-macroglobulin-bound elastase.

Bronchial leukocyte proteinase inhibitor (BLPI) is an 11.7 kDa, acid-stable protein found in mucous secretions, which inhibits neutrophil elastase. The Stoke's radius of BLPI calculated from sedimentation equilibrium and sedimentation velocity centrifugation data was in good agreement with the value determined by gel filtration. These data indicate that BLPI exists in a compact globular conformation at both neutral and acidic pH. BLPI, due to its small compact size, can inhibit neutrophil elastase after the enzyme has been complexed with alpha 2-macroglobulin (A-2-M) but alpha 1-proteinase inhibitor failed to inactivate A-2-M-bound elastase. The apparent association rates of BLPI and Eglin C with A-2-M-bound elastase were found to be 6.3 X 10(2) M-1s-1 and 1.1 X 10(3) M-1s-1, respectively. These apparent association rates decreased 168-fold for BLPI and 909-fold for Eglin C, relative to the association rates of these inhibitors with free elastase. These changes probably result from a combination of effects, such as inhibitor accessibility to the enzyme and/or reaction rate, but regardless of the mechanism these data suggest that BLPI may function to control both free and A-2-M-bound elastase.

Bronchi↗
PubMed1988

Demonstration by staining and radioautography of cyclical distributions of protein at the enamel surface in rat incisors.

Staining patterns in the enamel during the maturation stage of amelogenesis reflect the banded distribution of ruffle-ended and smooth-ended ameloblasts. This study investigated the possibility that proteins at the enamel surface may be distributed cyclically according to cyclical changes in ameloblast morphology. Dissected lower rat incisors were wiped free of their enamel organs and immediately immersed in fixative containing one of the following heavy metal and histological stains: uranyl acetate, lead citrate, Coomassie blue, alcian blue and ruthenium red. Other animals were injected with [35S]methionine to label newly-formed enamel proteins. Their incisors were dissected, the enamel organs were wiped from the enamel surface, and the teeth were processed as whole mounts for radioautography. Teeth stained by heavy metals were also viewed by back-scattered electron imaging. The in-situ staining revealed that proteins were distributed in bands and stripes across maturing enamel. Radioautography revealed that the proteins in the stripes were newly-synthesized and secreted into the enamel by certain maturation ameloblasts. We conclude that the enamel organ expresses cyclical activity in part through secretion of proteins.

Ameloblasts↗
PubMed1988

Effects of inspired oxygen tension on hemodynamics and pulmonary gas exchange in patients undergoing coronary artery surgery.

This study was designed to compare the effect of intraoperative administration of 100% oxygen (F1O2 = 1.0) with 50% O2 (air-O2 mixture, F1O2 = 0.5) on cardiovascular and respiratory parameters in adults undergoing coronary artery surgery. Nineteen patients were assigned to receive either F,O2 = 1.0 (group A) or F1O2 = 0.5 (group B) in a randomized fashion. Anesthesia was induced with fentanyl (15 microg/kg) and diazepam (0.1 to 0.2 mg/kg) and maintained with fentanyl (total dose 50 microg/kg) and isoflurane. A bubble oxygenator (F1O2 = 1.0) was used during cardiopulmonary bypass (CPB) in both groups. Hemodynamic and respiratory profiles were determined at specific intervals prior to incision, following CPB, and postoperatively. Patients ventilated with F1O2 = 0.5 were well oxygenated at measured intraoperative intervals (PaO2 range 90 to 268 mmHg, saturation 95% to 99%), with adequate mixed venous O2 levels (PvO2 range 35 to 65 mmHg, saturation 63% to 89%). Compared with patients receiving F1O2 = 1.0, those receiving F1O2 = 0.5 had significantly greater increases in cardiac index (CI) (mean +/- SEM B: 87% +/- 18% v A: 26% +/- 12%) and stroke index (B: 10% +/- 5% increase vA: 14% +/- 7% decrease), and a larger decrease in peripheral resistance (B: 38% +/- 7% v A: 4% +/- 12%) at postoperative day 1 relative to preincision values (P < 0.05). At postoperative day 1, both groups had an elevated alveolar-to-arterial O2 gradient (A: 55% +/- 19% v B: 48% +/- 17% increase) and shunt fraction (A: 58% +/- 28% v B: 99% +/- 35% increase). Although O2 consumption increased similarly in both groups at postoperative day 1 relative to preincision values (A: 91% +/- 23% v B: 113% +/- 16%), O2 delivery was enhanced more in group B than in group A (67% +/- 17% v 20% +/- 13% increase, respectively, P < 0.05). The data suggest that significant hemodynamic derangements may occur with hyperoxia and that intraoperative administration of 50% O2 may be more appropriate during coronary artery surgery.

Coronary Artery Bypass↗