A simple spreadsheet tool for cost accounting anesthesia care.
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Adult↗
Biomedical subjects
C E Smith
Publications and source records attributed to C E Smith.
A model of caregiving effectiveness for technologically dependent adults residing at home.
Caregiver-care-receiver interactions unique to this model of caregiving effectiveness were tested longitudinally in a randomly drawn national sample of 111 caregivers. Path analyses results indicate that variables explain variance in caregiver and patient quality of life, patient condition, and technological side effects. These findings extend nursing knowledge related to caregiving motivation-to-help and mutual interactions and thus have implications for home care practice. Effective family caregiving of loved ones dependent on technology for survival can result in enhanced patient condition, return to work, normalization of family life, and for society a reduction in health care costs.
Adaptation, Psychological↗
Characterization and expression of an antifungal zeamatin-like protein (Zlp) gene from Zea mays.
A cDNA clone encoding a basic thaumatin-like protein of Zea mays was recovered from a mid-development seed cDNA library. The gene, Zlp, encoded a protein that was nearly identical with maize zeamatin and alpha-amylase/trypsin inhibitor. Expression of Zlp mRNA was highest in the endosperm tissue of seed 4 weeks after pollination. Expression of zeamatin-like (ZLP) protein correlated with mRNA; also, a low basal level of ZLP expression in leaf was not appreciably induced by abiotic stresses. ZLP was expressed with its own signal peptide in insect cells and in transgenic Arabidopsis and tomato plants. ZLP was secreted in all three systems, with correct processing of the signal peptide. ZLP expressed in transgenic tomato was found to be partially subjected to a proteolytic cleavage after residue 180, by an unknown mechanism, to give a "nicked" isoform of ZLP. Purified ZLP from all three sources, as well as purified "nicked" ZLP from tomato, demonstrated fungal inhibition against Candida albicans and Trichoderma reesei, with marginal inhibition observed against Alternaria solani and Neurospora crassa.
Amino Acid Sequence↗
Characterization of human uroguanylin: a member of the guanylin peptide family.
Guanylin, a peptide homologue of the bacterial heat-stable enterotoxins (ST), is an endogenous activator of guanylate cyclase C (GC-C). We have initiated a search for other members of the guanylin peptide family and in the current study describe a "guanylin-like peptide" from human urine. Bioactivity was monitored by determining the effect of urine extracts on T84 cell guanosine 3',5'-cyclic monophosphate (cGMP) levels. Purification yielded two bioactive peaks of peptides that, when sequenced by NH2-terminal analysis, possessed 15 and 16 amino acids. The sequence of the smaller peptide represented an NH2-terminal truncation of the larger peptide. We have termed the larger peptide human uroguanylin; it has the following amino acid sequence: NDDCELCVNVACTGCL. Human uroguanylin shares amino acid sequence homology with guanylin and ST. Synthetic uroguanylin increased cGMP levels in T84 cells, competed with 125I-labeled ST for receptors, and stimulated Cl- secretion as reflected by an increased short-circuit current. Thus we report the isolation from human urine of a unique peptide, uroguanylin, that behaves in a manner similar to guanylin and appears to be a new member of this peptide family.
Adult↗
Order and specificity of the Plasmodium falciparum hemoglobin degradation pathway.
The human malaria parasite, Plasmodium falciparum, degrades nearly all its host cell hemoglobin during a short segment of its intraerythrocytic development. This massive catabolic process occurs in an acidic organelle, the digestive vacuole. Aspartic and cysteine proteases have been implicated in this pathway. We have isolated three vacuolar proteases that account for most of the globin-degrading activity of the digestive vacuole. One is the previously described aspartic hemoglobinase that initiates hemoglobin degradation. A second aspartic protease is capable of cleaving hemoglobin with an overlapping specificity, but seems to prefer acid-denatured globin. The third is a cysteine protease that does not recognize native hemoglobin but readily cleaves denatured globin. It is synergistic with the aspartic hemoglobinase, both by in vitro assay of hemoglobin degradation, and by isobologram analysis of protease inhibitor-treated parasites in culture. The cysteine protease is highly sensitive to chloroquine-heme complex, suggesting a possible mechanism of 4-aminoquinoline antimalarial action. The data suggest an ordered pathway of hemoglobin catabolism that presents an excellent target for chemotherapy.
Amino Acid Sequence↗
Snoring and sleep apnea: evaluation and treatment.
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Humans↗
Exacerbation of asthma after pyridostigmine during Operation Desert Storm.
Pyridostigmine was first used extensively during Operation Desert Storm for prophylaxis against the effects of nerve agents. After initial reports of asthma exacerbations following its use, we gave 10 asthmatic and 6 non-asthmatic soldiers a 30-mg dose of pyridostigmine. We found no changes in forced vital capacity in any of the soldiers, but observed exacerbation of asthma symptoms in seven of the asthmatics. Severity of the exacerbation correlated best with severity of asthma in the desert and inversely with body weight. The irritant effect of the dust may predispose asthmatics to worsen after pyridostigmine, an effect not seen in the laboratory.
Adult↗
Uroguanylin: structure and activity of a second endogenous peptide that stimulates intestinal guanylate cyclase.
The intestinal hormone guanylin and bacterial heat-stable enterotoxins (STs) are members of a peptide family that activates intestinal membrane guanylate cyclase. Two different peptides that activate the human intestinal T84 cell guanylate cyclase have been purified from urine and intestinal mucosa of opossums (Didelphis virginiana). The highly acidic peptide, QEDCELCINVACTGC, was named uroguanylin because it was isolated from urine and shares 53% identity with guanylin. A second peptide, SHTCEICAFAACAGC, was purified from urine and intestinal mucosa. This alanine-rich peptide was 47% identical to uroguanylin and 73% identical to human guanylin, suggesting that it may be an opossum homologue of guanylin. Synthetic uroguanylin-(2-15) (i.e., EDCELCINVACTGC) was 10-fold more potent than synthetic rat guanylin, but both peptides were less potent than Escherichia coli ST in the T84 cell cGMP bioassay. Uroguanylin-(2-15) and guanylin inhibited 125I-ST binding to T84 cell receptors in competitive radioligand binding assays. Transepithelial Cl- secretion was stimulated by 1 microM uroguanylin, indicated by an increase in the short circuit current of T84 cells. Thus, uroguanylin is another paracrine hormone in the emerging peptide family that activates intestinal membrane guanylate cyclase. The second peptide may be the opossum form of guanylin, or perhaps, it is still another member of this peptide family. The presence of uroguanylin and guanylin in urine and receptors in proximal tubules suggests that these peptides may also originate from renal tissue and may regulate kidney function.
Amino Acid Sequence↗
Identification of the sites of phosphorylation in insulin-like growth factor binding protein-1. Regulation of its affinity by phosphorylation of serine 101.
Serine phosphorylation of insulin-like growth factor binding protein-1 (IGFBP-1) has been shown to alter its affinity for the insulin-like growth factors (IGF-I and IGF-II) and to modify its capacity to modulate cellular responses to the IGFs. Because of this, we determined the sites of serine phosphorylation. Purification of 32P-labeled IGFBP-1 was followed by digestion with trypsin and endoproteinase Glu-C and radiosequencing of labeled peptides. Three serines were found to be phosphorylated, with Ser101, Ser119, and Ser169 containing 70%, 5%, and 25% of the incorporated 32P, respectively. A mutated IGFBP-1, substituting alanine for serine at positions 98 and 101, was expressed in CHO cells. On nondenaturing gels, the wild type protein migrated as five isoforms (one non-phosphorylated and four phosphorylated). However, in the mutated protein, the most rapidly migrating band (a phosphorylated form) was not present. The cells containing the mutated cDNA incorporated 60% less 32P into immunoprecipitable IGFBP-1. The mutated protein had a 3-fold reduction in affinity for IGF-I compared to the wild type protein. We conclude that Ser101 represents the major site of phosphorylation containing 63% of the total 32P incorporated and that phosphorylation of Ser101 is important for maintenance of high affinity binding for this growth factor.
Alanine↗
Effects of chronic fluoride exposure on morphometric parameters defining the stages of amelogenesis and ameloblast modulation in rat incisors.
The response of ameloblasts to long-term (6 weeks) exposure to 100 ppm fluoride was examined in continuously erupting mandibular incisors of female Sprague-Dawley rats as compared to control rats receiving a similar diet (Teklad L-356) but no sodium fluoride in their drinking water. After treatment, animals from both groups were perfused intravascularly with glutaraldehyde, and the incisors were removed and processed for light microscope morphometric analyses directly from 1 microns thick Epon sections. Other animals were injected intravenously with calcein (green fluorescence) followed 4 hours later by xylenol orange (red fluorescence) in order to reveal smooth-ended ameloblast modulation bands and thereby allow quantification of parameters related to the creation and movement of modulation waves within the maturation zone of these teeth. The results indicated that rat incisors expressed four major changes in normal amelogenesis which could be attributed to the chronic fluoride treatment. First, ameloblasts produced a thinner than normal enamel layer by the time they completed the secretory stage and entered the maturation stage of amelogenesis. Second, enamel organ cells within the maturation zone, especially those from the papillary layer, were shorter in height than normal. Third, ameloblasts related to maturing enamel in areas where it was partially soluble and/or fully soluble in EDTA modulated at a rate that was much slower than normal. In some locations ameloblasts remained ruffle-ended for as much as 30% longer than normal per cycle. This upset the usual pattern such that fewer total modulation cycles were completed per unit time by these ameloblasts. Fourth, enamel proteins were lost from the maturing enamel layer at a rate that was about 40% slower than normal. The data suggested that ameloblasts detected the delay in the extracellular breakdown and/or loss of enamel proteins and they responded by remaining ruffle-ended for longer intervals than usual (positive feedback).
Ameloblasts↗
Prevention of hypoxemia during lumbar puncture in infancy with preoxygenation.
Hypoxemia has previously been reported during lumbar puncture (LP) in infancy. The purpose of this study was to determine whether preoxygenation before the LP would reduce hypoxemia during the procedure in infants. Twenty-one infants (one to 15 weeks of age) undergoing LP for evaluation of possible sepsis were randomly assigned to the control group (12) or treatment group (9). The treatment group was preoxygenated breathing oxygen (FiO2 = 1.0) spontaneously via snug face mask for three minutes prior to being positioned for the LP. The control group spontaneously breathed room air during this interval. Oxyhemoglobin saturation was measured prior to, and continuously during, the LP with pulse oximetry. The groups were comparable in age, resting respiratory rate, baseline saturation, and duration of the procedure. The treatment group developed significantly less desaturation during the procedure than the control group (P < 0.05). We conclude that preoxygenation prior to LP prevents most of the hypoxemia resulting from the procedure in infants.
Female↗
Responsibilities and reactions of family caregivers of patients dependent on total parenteral nutrition at home.
This prospective study assessed the caregiving responsibilities and reactions of family members who provide home care to a relative who is dependent on total parenteral nutrition (TPN). A short, semistructured interview based on the Roy adaptation model was used to gather data about the caregiving experiences of 20 relatives of adult TPN-dependent patients. Data were content analyzed, and frequently occurring themes identified. Results indicated that altered family responsibilities as well as negative and positive psychologic reactions to caregiving do occur. The interviews suggested that caregivers master TPN technology but make little use of assistance from extended family or professionals. Although depression and fatigue were reported as common, these family members felt capable and successful in their caregiving roles. Further longitudinal research with larger samples should allow for comparison of caregivers on demographic differences, stress, and other variables pertinent to managing complex home care.
Adaptation, Psychological↗
High-level production of active HIV-1 protease in Escherichia coli.
High levels of active HIV-1 protease (PR) were produced in Escherichia coli, amounting to 8-10% of total cell protein. High production levels were achieved by altering the following parameters: (1) codon preference of the coding region, (2) A+T-richness at the 5' end of the coding region, and (3) promoter. To circumvent the toxicity of HIV-1 PR in E. coli, the gene was expressed as a fusion protein with two different proteolytic autocleavage sequences. In both the cases, the fusion protein could be cleaved in vivo to give an active molecule with the native sequence at the N terminus.
Amino Acid Sequence↗
Isolation and characterization of a 25 kDa antifungal protein from flax seeds.
We have purified a 25 kDa protein from flax seeds to homogeneity by polyethyleneimine precipitation, ammonium sulfate precipitation, chitin extraction, Mono S cation exchange and C18 reversed phase column chromatographies. The purified protein strongly inhibited the growth of the agronomically important pathogen Alternaria solani, the causative agent of tomato early blight and in synergy with nikkomycin Z strongly inhibited the human pathogen Candida albicans. Amino terminal sequence analysis of the purified protein indicated that it has a high degree of homology to other reported pathogenesis-related antifungal proteins.
Alternaria↗
Antifungal proteins from plants. Purification, molecular cloning, and antifungal properties of chitinases from maize seed.
We have purified two 28-kDa chitinases, designated Chitinase A (Chit A) and Chitinase B (Chit B), from maize seeds to homogeneity and isolated cDNA clones encoding these two enzymes using an oligonucleotide probe based on an amino acid sequence of a peptide derived from Chit A. Although these two enzymes share 87% homology in their amino acid sequences, which were deduced from the nucleotide sequences of the isolated cDNA clones, they are significantly different in their biochemical and in vitro antifungal activities. When tested in vitro for antifungal activity against the growth of Trichoderma reesei, Alternaria solani, and Fusarium oxysporum, Chit A showed greater antifungal activity than Chit B. The specific activity of Chit A was determined to be 3-fold higher than that of Chit B. Chit A also had a 10-fold lower binding constant (Kd) against the substrate analogue N,N',N'',N'''-tetraacetyl chitotetrose than Chit B, indicating that the two enzyme may differ in their affinities for binding to the substrate chitin. Comparison of the amino acid sequences of maize seed chitinases with those of previously published chitinases from monocot and dicot plants indicates that maize seed chitinases have diverged significantly from other chitinases.
Alternaria↗
Identification of an essential tyrosine residue in the catalytic site of a chitinase isolated from Zea mays that is selectively modified during inactivation with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide.
Chitinase isolated from Zea mays seeds is inactivated by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) in the absence of exogenous nucleophiles. Oligomers of N-acetylglucosamine,N,N',N",N"'-tetra-N-acetylchitotetraose (GlcNAc4), and to a lesser extent, N,N',N"-tri-N-acetylchitotriose (GlcNAc3) and N,N'-di-N-acetylchitobiose (GlcNAc2) provide partial protection against inactivation by the reagent. An examination of the concentration dependence of the protection afforded by GlcNAc4 revealed direct competition between the substrate analog and the reagent for the same binding sites on the enzyme. Isolation and Edman degradation of a "new" tryptic fragment, observed after inactivation of chitinase with EDC, revealed the sequence G-P-L-Q-I-S-W-N-*-N-Y-G-P-A-G-R, where the asterisk represents a cycle in which no amino acid was detected, presumably as a consequence of derivatization with EDC. In basic chitinases from dicotyledonous plants such as Arabidopsis thaliana, Phaseolis vulgaris (bean), Nicotiana tabacum (tobacco), and Solanum tuberosum (potato), as well as in the chitinase isolated from the monocotyledonous plant Hordeum vulgare (barley), this position is invariably occupied by a tyrosine. However, in the Oryza sativa (rice) basic chitinase, this position is occupied by a phenylalanine. The following additional evidence supports identification of this residue as tyrosine in Z. mays chitinase. (a) Inactivation of chitinase with EDC is reversible by treatment with hydroxylamine. (b) Liquid secondary ion mass spectrometric analysis of the isolated derivatized peptide revealed the presence of a molecular ion with a mass to charge ratio consistent with the peptide containing a derivatized tyrosine residue. These results provide evidence for an essential tyrosine residue at or near the catalytic site of chitinase that is selectively modified during inactivation with EDC.
Acetylglucosamine↗
A note on neuronal firing and input variability.
The Ornstein-Uhlenbeck process with a constant forcing function has often been used as a model for the subthreshold membrane potential of a neuron. The mean, variance and coefficient of variation of the first passage time to a constant threshold are examined for this model in the limit of small synaptic noise and low thresholds. A comparison is made between the asymptotic results of Wan & Tuckwell, who used perturbation analysis, and several computationally simpler approximation methods. A generalization of Stein's method gives an overestimate of the mean interval while an approximation by a Wiener process with linear drift gives an underestimate of the mean interval. These bounds are simple to calculate and can be used as a prelude to a more detailed perturbation analysis.
Animals↗
Guanylin: an endogenous activator of intestinal guanylate cyclase.
Intestinal guanylate cyclase mediates the action of the heat-stable enterotoxin to cause a decrease in intestinal fluid absorption and to increase chloride secretion, ultimately causing diarrhea. An endogenous ligand that acts on this guanylate cyclase has not previously been found. To search for a potential endogenous ligand, we utilized T84 cells, a human colon carcinoma-derived cell line, in culture as a bioassay. This cell line selectively responds to the toxin in a very sensitive manner with an increase in intracellular cyclic GMP. In the present study, we describe the purification and structure of a peptide from rat jejunum that activates this enzyme. This peptide, which we have termed guanylin, is composed of 15 amino acids and has the following amino acid sequence, PNTCEICAYAACTGC, as determined by automated Edman degradation sequence analysis and electrospray mass spectrometry. Analysis of the amino acid sequence of this peptide reveals a high degree of homology with heat-stable enterotoxins. Solid-phase synthesis of this peptide confirmed that it stimulates increases in T84 cyclic GMP levels. Guanylin required oxidation for expression of bioactivity and subsequent reduction of the oxidized peptide eliminated the effect on cyclic GMP, indicating a requirement for cysteine disulfide bond formation. Synthetic guanylin also displaces heat-stable enterotoxin binding to cultured T84 cells. Based on these data, we propose that guanylin is an activator of intestinal guanylate cyclase and that it stimulates this enzyme through the same receptor binding region as the heat-stable enterotoxins.
Amino Acid Sequence↗