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Biomedical subjects

C E Smith

Publications and source records attributed to C E Smith.

At least 163 records · Page 9Linked to original sources
PubMed1991

cDNA cloning and nucleotide sequence of the wheat streak mosaic virus capsid protein gene.

The 3'-terminal region of wheat streak mosaic virus (WSMV) genomic RNA was cloned and a cDNA sequence of 1809 nucleotides upstream of the poly(A) tract was determined. The sequence contains a single open reading frame of 1662 nucleotides and a 3' untranslated region of 147 nucleotides. Translation products from WSMV RNA and WSMV cDNA transcripts were immunoprecipitated by WSMV capsid protein antiserum, indicating that the 3'-terminal region of WSMV RNA encodes the capsid protein. Five potential N-terminal capsid protein protease cleavage sites were identified, which would yield proteins ranging from 31.7K to 46.8K. Alignment of the deduced amino acid sequence of the WSMV capsid protein with those of other potyviruses showed significant, but limited, identity as compared to the alignment of two or more aphid-transmitted potyviruses. Although WSMV has characteristics distinct from potyviruses, because of its particle morphology, translation strategy apparently based on polyprotein processing, the ability to form cytoplasmic cylindrical inclusions and the degree of capsid protein homology with aphid-transmitted potyviruses, it should be considered a member of the potyvirus group.

Amino Acid Sequence↗
PubMed1991

Determination of the disulfide bond pairings in bovine transforming growth factor-alpha.

A rapid method for determining the three disulfide bond pairings in bovine transforming growth factor-alpha (bTGF-alpha) was developed by digesting bTGF-alpha with thermolysin followed by separation of the generated peptides by reversed-phase HPLC. The disulfide-bonded peptides were identified by amino acid sequencing and fast atom bombardment mass spectrometry. The disulfide bond pairings in bTGF-alpha were determined to be homologous to those in the human and mouse TGF-alpha molecules. A species of low bioactivity isolated from the folding/oxidation mixture of chemically synthesized bTGF-alpha was demonstrated to contain two incorrect disulfide bonds. These results indicate that mispairing of disulfide bonds in bTGF-alpha significantly reduces the activity of this molecule.

Amino Acid Sequence↗
PubMed1991

Technological dependency: a preliminary model and pilot of home total parenteral nutrition.

As hospital costs increase and durations of hospital stays decrease, clients are being discharged to home care in more acute states and often with demands for high technology therapy. To assist in understanding the experiences families face in adapting to either short- or long-term dependence on technology, a model was developed from literature and research review. The literature review suggested that self-care practices affected each of the family members' adaptation. The model was developed to indicate self-care issues and problems impacting adaptation to high technology at home. A pilot study was conducted to determine if interviews and questionnaires would collect data necessary to test the model. This article describes the pilot study results. Data indicated that relationships and role changes did occur after the family became technologically dependent. Also, although depression and anxiety were common responses, the family members felt capable and successful in their caregiving roles.

Adaptation, Psychological↗
PubMed1991

Circulatory effects of verapamil during normovolemic hemodilution in anesthetized rats.

Patients who have undergone perioperative normovolemic hemodilution may require calcium channel blockers for the treatment of myocardial ischemia and/or supraventricular tachyarrhythmias. The purpose of this rodent study was to examine the effect of intravenous verapamil on the hyperdynamic circulatory response to acute normovolemic hemodilution (hematocrit 20%). Anesthetized animals were randomly divided into four groups equal in number: (1) controls (no hemodilution, no drug); (2) hemodilution only; (3) verapamil only; and (4) hemodilution followed by verapamil. Cardiac output was recorded using an electromagnetic flow probe. Pre- and afterload tests were performed, the former consisting of rapid infusion of blood adjusted for hematocrit, the latter consisting of an aortic clamp technique. Animals in group 2 had significantly (P less than 0.05) greater percent increases in cardiac index, stroke volume index, and dP/dt, and greater percent decreases in mean arterial pressure, systemic vascular resistance, and oxygen delivery than did control animals (group 1). Infusion of verapamil after hemodilution (group 4) did not interfere with the compensatory increases in cardiac index and stroke volume index seen in group 2, nor did it reduce the peak stroke volume index in response to preload stress, although it did reduce resting dP/dt, mean arterial pressure and systemic vascular resistance, and peak cardiac index and "left ventricular developed pressure" after preload and afterload stress, respectively. We conclude that reduced ventricular function after verapamil administration does not interfere with the compensatory increase in stroke volume index after normovolemic hemodilution.

Animals↗
PubMed1991

Adaptation in families with a member requiring mechanical ventilation at home.

Current health care trends indicate that ventilator-dependent patients increasingly will be discharged to home after shorter hospitalizations. The purpose of this study was to determine how care givers adapt to having ventilator-dependent adults at home. Twenty families were interviewed in their homes by using an eight-question semistructured interview guide. The Roy model was used as a framework to analyze these data. Two instruments, the Family Coping Scale (F-COPES) and the Family APGAR, were administered to measure family coping and function. Patients, aged 18 to 74 years, required 24-hour (n = 9), 12- to 15-hour (n = 5), or 8- to 12-hour (n = 6) home ventilatory support and had neuromuscular or trauma-related diagnoses. Months receiving ventilation ranged from 2 to 312. Care givers, aged 20 to 74 years, were all relatives. Six care givers reported using support services outside their extended family. F-COPES scores fell within national norms whether the patient required 24-hour or less ventilation. Family APGAR results revealed satisfaction with overall family function although scores decreased over time. Interview data indicated that essential knowledge and skills are taught but additional information is desired. Both positive and negative responses to care giving were identified, with the majority of responses being concerned with role mastery, self-concept, and dependency issues. Positive themes in the interviews reflected confidence in ventilator care, satisfaction with the decision to care for their family member at home, and improved quality of life. Negative themes in the interviews reflected the burden of care giving, the dependence of the patient on the care giver, resentment, and hopelessness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗
PubMed1990

Ultrastructural distribution of NADPase within the Golgi apparatus and lysosomes of mammalian cells.

Cytochemical studies with over 40 different mammalian cell types have indicated that NADPase activity is associated with the Golgi apparatus and/or lysosomes of all cells. In the majority of cases, NADPase is restricted to saccular elements comprising the medial region of the Golgi stack and an occasional lysosome. There is often weak NADPase activity in other Golgi compartments such as the trans Golgi saccules and/or elements of the trans Golgi network. In some cells, however, strong NADPase activity is found within these latter compartments, either exclusively in trans Golgi saccules or elements of the trans Golgi network, or in combination with medial Golgi saccules and each other including (1) medial Golgi saccules + trans Golgi saccules, (2) medial Golgi saccules + trans Golgi saccules + trans Golgi network, or (3) trans Golgi saccules + trans Golgi network. In some rare cases, no NADPase activity is detectable in either Golgi saccules or elements of the trans Golgi network, but it is observed in an occasional lysosome or throughout the lysosomal system of these cells. It is unclear at present if these variations in the distribution of NADPase across the Golgi apparatus, and between the Golgi apparatus and lysosomal system, are due to differences in targeting mechanisms or to the existence of "bottlenecks" in the natural flow of NADPase along the biosynthetic pathway toward lysosomes. While no clear pattern in the association of strong NADPase activity with lysosomes was apparent relative to the ultrastructural distribution of NADPase activity in Golgi saccules or elements of the trans Golgi network, the results of this investigation suggested that cells having NADPase localized predominantly toward the trans aspect of the Golgi apparatus (in trans Golgi saccules or elements of the trans Golgi network or both) have few NADPase-positive lysosomes. The only exception is hepatocytes which were classified as predominantly trans but had noticeable NADPase activity within medial Golgi saccules and elements of the trans Golgi network as well, and highly reactive lysosomes. Other cells showing highly reactive lysosomes including (1) Kupffer cells of liver and those forming the proximal convoluted tubules of the kidney, both of which also had strong NADPase activity within medial and trans Golgi saccules and elements of the trans Golgi network, (2) Leydig cells of the testis and interstitial cells of the ovary, which also showed strong NADPase activity within medial Golgi saccules, and (3) macrophages from lung, spleen and testis, and Sertoli cells from the testis all of which showed no Golgi associated NADPase activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Alpha-adrenergic agonist drugs, left ventricular function, and emergency from cardiopulmonary bypass.

The relationship between preoperative left ventricular (LV) dysfunction and the use of alpha-adrenoceptor agonists during weaning from cardiopulmonary bypass was studied in 102 patients undergoing coronary artery surgery. LV function was evaluated subjectively by examination of the 30 degree right anterior oblique left ventriculogram. Group 1 consisted of 75 patients with normal or mild impairment in LV function, whereas group 2 consisted of 27 patients with moderate-severe LV dysfunction. Cardiovascular parameters were measured at baseline, during hypothermic bypass with the aorta clamped, during normothermic bypass after unclamping, and 1 and 15 minutes after separation from bypass. Thirty-seven patients in group 1 (49%) and 11 patients in group 2 (39%) required some form of inotropic and/or vasopressor support during weaning from bypass. Group 2 required significantly higher cumulative doses of phenylephrine after bypass compared with group 1 (1.69 +/- 0.70 mg, n = 9, v 0.24 +/- 0.04 mg, n = 27, P less than 0.05). Similarly, the dose of norepinephrine infusion in group 2 was 3.3 times that in group 1 (10 +/- 6 micrograms/min, n = 2, v 3 +/- 0.6 micrograms/min, n = 2, P = NS). The higher doses of alpha-adrenoceptor agonists required in patients with moderate-severe LV dysfunction may be due to differences in alpha-adrenoceptor agonist affinity and/or receptor density.

Adrenergic alpha-Agonists↗
PubMed1990

Pretreatment with non-depolarizing neuromuscular blocking agents and suxamethonium-induced increases in resting jaw tension in children.

We have studied the effect of prior administration of non-depolarizing neuromuscular blocking drugs on suxamethonium-induced increases in masseter muscle tension in 21 children aged 3-10 yr, anaesthetized with nitrous oxide and halothane using supramaximal stimulation of the ulnar nerve and the nerve to masseter. Resting tension and isometric force of contraction were measured in the adductor pollicis and masseter muscles. A sub-paralysing dose of tubocurarine 0.05 mg kg-1, a paralysing dose of atracurium 0.5 mg kg-1 or saline was given, followed 3 min later by suxamethonium 1 mg kg-1. Onset times of suxamethonium and atracurium block were shorter in the masseter than in the adductor pollicis muscle. When preceded by a sub-paralysing dose of tubocurarine, suxamethonium produced an increase in masseter tension (47 (SEM 15) g) similar to that produced by suxamethonium alone (59 (13) g). Prior administration of a paralysing dose of atracurium almost abolished this increase in tension (2.5 (2.5) g) (P less than 0.05 vs saline). The tension increase in adductor pollicis was 0, 3.2 (2.2) and 5.9 (1.1) g in the atracurium, tubocurarine and saline groups, respectively. Tubocurarine and atracurium prevented muscle fasciculations in all patients. It was concluded that increased muscle tone is a normal response to suxamethonium and is greater in the masseter than adductor pollicis. Sub-paralysing doses of non-depolarizing neuromuscular blockers have little effect, in contrast with paralysing doses. This suggests that the effect is mediated via postsynaptic receptors.

Ambulatory Surgical Procedures↗
PubMed1990

Vegetative/Parasitic transition: control and plasticity in striga development.

Striga asiatica (Scrophulariaceae), an obligate parasite of grasses including many of the world's major grain crops, switches from vegetative to parasitic development by the differentiation of the root meristem into the host attachment organ, the haustorium. This change was induced in culture by the exposure to a single, low molecular weight signal molecule, 2,6-dimethoxy-p-benzo-quinone. A concentration of 10(-6) molar quinone and an exposure time of >/=6 hours were required before the developmental process could be completed. With shorter exposure times, haustorial development was prematurely aborted and meristematic elongation was reestablished. The new meristem was capable of developing a second haustorium if reexposed to the signal molecule. These results are discussed in terms of the transition to the parasitic phase and the general control of plant cellular development.

Journal Article↗
PubMed1990

Failure of ceftazidime-amikacin therapy for bacteremia and meningitis due to Klebsiella pneumoniae producing an extended-spectrum beta-lactamase.

A multiple trauma patient failed treatment with ceftazidime and amikacin for bacteremia and meningitis due to a Klebsiella pneumoniae strain that produced a novel, plasmid-mediated beta-lactamase. Both pre- and posttreatment isolates were resistant to ceftazidime (MIC, greater than or equal to 64 micrograms/ml) and various penicillins but not to other expanded-spectrum cephalosporins. The beta-lactamase had a pI of 5.25 and was encoded on a conjugal plasmid of approximately 150 kilobases. DNA hybridization studies indicated that the enzyme was a TEM derivative.

Adult↗
PubMed1990

Routine use of backscattered electron imaging to visualize cytochemical and autoradiographic reactions in semi-thin plastic sections.

The scanning electron microscope (SEM) was used to examine cytochemical and autoradiographic reactions in 2-microns semi-thin sections of tissues conventionally fixed and embedded in various resins. The sections were examined using both the secondary and backscatter modes of the SEM at magnifications within the range attainable with the light microscope. Both modes allowed the imaging of phosphatase reaction product using cerium and lead capture, lectin-gold, and immunogold labeling, with and without silver enhancement, and autoradiography. Backscattered electron imaging (BEI), however, provided images with more contrast and structural details. This approach allows examination of large sections, with more contrast and resolution than the light microscope, and visualization of reactions not visible with this instrument. The improved imaging and the simple and conventional preparation of specimens indicate that BEI can be used routinely to examine tissue organization, cell structure, and the content of the various cell compartments with a resolution approaching that of transmission electron microscopy.

Ameloblasts↗
PubMed1990

Oxidant effects on rat and human lung proteinase inhibitors.

This project tested the hypothesis that inhaled oxidants could cause lung damage by inactivating the proteinase inhibitors that normally protect the lung from proteolysis. Rat alpha-1-proteinase inhibitor (alpha 1-PI)2 was purified from blood plasma, and antibodies to this inhibitor were prepared. The activity of alpha 1-PI in lung lavage fluids from rats was measured by elastase inhibition, and the immunological concentration of alpha 1-PI was quantified in an enzyme-linked immunoassay. The ratio of the amount of active alpha 1-PI relative to its immunological concentration was examined as a measure of the inhibitor's functional activity. This ratio and the ratio of the immunological concentration of alpha 1-PI to the total protein concentration were determined in lung lavage fluids from rats exposed to air, 10 parts per million (ppm) nitrogen dioxide, and diesel emissions (3.5 mg/m3 particulates) for 12, 18, and 24 months. Only diesel exposures resulted in a statistically significant reduction in the functional activity of alpha 1-PI of 30 percent (p less than 0.05). Similar studies were performed on rats exposed to nitrogen dioxide (0.5 ppm background with peaks of 1.5 ppm) and ozone (0.06 ppm background with peaks of 0.25 ppm) for 12 and 18 months. No statistically significant effects were observed in the functional activity of alpha 1-PI or its immunological concentration. In other protocols, rats were acutely exposed to 0.8 ppm or 1.2 ppm ozone for two, four, or eight hours, and to 0.5 ppm or 0.8 ppm ozone in conjunction with 8 percent carbon dioxide for two or seven hours. Although these acute exposure conditions did not reduce the functional activity of alpha 1-PI, the immunological concentration of alpha 1-PI and the elastase inhibitory activity, relative to other proteins, were significantly increased in relation to the total amount of ozone inhaled. The functional activity of alpha 1-PI also was measured in the bronchoalveolar lavage fluids of human subjects exposed to nitrogen dioxide (0.05 ppm with 2 ppm peaks, or to 1.5 ppm continuously) for three hours and to ozone (0.4 ppm) for two hours during exercise. These exposures did not result in significant changes in the functional activity of alpha 1-PI or its immunological concentration.(ABSTRACT TRUNCATED AT 400 WORDS)

Air Pollutants↗
PubMed1990

Inflammatory responses and the generation of chemoattractant activity in cowpox virus-infected tissues.

Histological examination of the lesions produced on the chick chorioallantois infected with cowpox virus shows extensive haemorrhage but there are few inflammatory cells. However, infection with a deletion mutant, white cowpox virus, results in little haemorrhage but there is massive polymophonuclear cell infiltration. Extracts from tissues infected with the parental, red cowpox virus contained little or no chemoattractant activity detectable in micropore filter assays. However, white cowpox virus-infected tissue extracts, including cellular extracts from infected tissue cultures, had a marked effect in vitro on the migration of both neutrophils and monocytes. The chemoattractant activity induced in ovo by white cowpox virus infection has sedimentation characteristics in sucrose density gradients that are similar to leukotactic factors shown previously to be present in the allantoic fluid of chick embryos infected with paramyxoviruses. Induction of chemoattractant activity did not occur after infection of chick chorioallantois with a recombinant white cowpox virus constructed to express a protein that is responsible for the haemorrhagic character of red cowpox virus. This gene product has been shown previously to have homology with various serine protease inhibitors. The significance of these studies to the immunogenicity and pathogenicity of vaccinia recombinant viruses is discussed.

Allantois↗
PubMed1989

Identification, purification, and characterization of truncated forms of the human nerve growth factor receptor.

We report the presence of truncated forms of the nerve growth factor receptor (NGFRt) in the conditioned medium of the human melanoma cell line A875 and in human urine and amniotic fluid. Radioiodinated nerve growth factor (125I-NGF) specifically bound to NGFRt was chemically cross-linked. After immunoprecipitation, labeled receptor species were visualized by autoradiography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NGFRts were purified from human adult male urine or a mixture of human amniotic fluid and infant urine by using a combination of either ion exchange chromatography (adult) or ammonium sulfate precipitation (infant) and immunoaffinity chromatography. Typical yields were about 1 microgram/liter of adult urine and 75 micrograms/liter of amniotic fluid/infant urine. The purified proteins, with molecular masses of 45, 40, and 35 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (12%), were confirmed to be NGFRts by amino-terminal sequencing and were designated NGFRt-1, NGFRt-2, and NGFRt-3, respectively. The isoelectric points of these three species ranged from 3.3 to 3.95 and displayed intraspecies heterogeneity; subsequently, amino acid residues covalently modified with sialic acid-containing carbohydrates were documented. The binding affinities of these species for nerve growth factor were comparable to that of the low affinity cell surface receptor. The potential to isolate milligram quantities of human NGFRts allows for model studies of the physicochemical structure of the intact receptor and the generation of polyclonal antibodies to study the biological functions of the NGF receptor.

Amniotic Fluid↗
PubMed1989

Clonal characterization of the human IgG antibody repertoire to Haemophilus influenzae type b polysaccharide. II. IgG antibodies contain VH genes from a single VH family and VL genes from at least four VL families.

To define the V gene family repertoire of human IgG anti-Haemophilus influenzae type b polysaccharide antibodies, we purified six IgG1 and nine IgG2 anti-Hib-PS antibodies to monoclonality from immune serum of six individuals and performed N-terminal amino acid sequence analysis. Of the 15 clonal antibodies we examined, all H chain V regions were of the VHIII family. In contrast, the L chains of these antibodies were clearly from at least four different VL families; VKI, VKII, VKIII, and V lambda. Interestingly. VL family expression correlated with the cross-reactivity of these antibodies to the capsular carbohydrate of Escherichia coli K100. VKII antibodies did not cross-react, whereas antibodies expressing V lambda, VKI, or VKIII generally cross-reacted. We conclude that L chain V regions are very important contributors to the limited heterogeneity in this antibody repertoire.

Adult↗
PubMed1989

In vitro and in vivo activity of chymotrypsin-activated big endothelin (porcine 1-40).

We investigated whether big endothelin (porcine 1-40) had contractile activity in isolated rat aorta or pressor activity when injected intravenously into the anesthetized rat. When isolated rat aorta was exposed to a 100 nM concentration of big endothelin, 4.8% of a maximal KCl contraction was observed, compared to 131% of KClmax when paired aortic rings were exposed to an equivalent concentration of synthetic endothelin. Likewise, big endothelin had very weak pressor activity when injected intravenously into anesthetized, ganglion-blocked rats at 10 nmol/kg. When big endothelin was incubated with chymotrypsin, native endothelin and other peptide fragments were formed. Chymotrypsin-treated big endothelin produced an endothelin-like contraction when applied to isolated rat aortic rings, and a characteristic endothelin-like effect on blood pressure in vivo. Our results indicate that the biological activity of endothelin could be effectively blocked by inhibiting the enzyme which converts big endothelin to endothelin.

Amino Acid Sequence↗