History of automated delivery of anesthetic agents.
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Anesthesia↗
Biomedical subjects
B E Smith
Publications and source records attributed to B E Smith.
Pharmacokinetics without calculus--an introduction.
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Anesthetics, Intravenous↗
Primary lateral sclerosis: a neuropsychological study.
Nine patients with clinically diagnosed, radiologically supported primary lateral sclerosis underwent cognitive testing. None was demented, but eight had mild cognitive impairment. Performances were most consistently impaired on neuropsychological tests sensitive to frontal lobe functions, followed by tests sensitive to memory. Cognitive testing may be useful in helping to establish a cortical localization in patients with the syndrome of progressive spasticity. There are potential nosologic relations between primary lateral sclerosis and other degenerative frontal lobe syndromes, such as frontal lobe dementia and progressive spasticity with dementia.
Adult↗
Fostering multiculturalism: the English Conversation Pairs Program.
Exposure to and personal interactions with people of diverse cultures foster an acceptance of multiculturalism. To this end, the English Conversation Pairs Program provides weekly conversation sessions between students who are native speakers of English (NSE) and students who speak English as a second language (ESL). Attitudes of twenty-two NSE students are surveyed before and after participation in the Conversation Pairs Program. This paper discusses (a) NSE students' perceptions of the program, (b) perceived changes in cultural sensitivity of NSE students, (c) activities which enhance and/or hamper program effectiveness, and (d) variables which influence program effectiveness.
Acculturation↗
EPR and electron nuclear double resonance (ENDOR) studies show nitrite binding to the type 2 copper centers of the dissimilatory nitrite reductase of Alcaligenes xylosoxidans (NCIMB 11015).
EPR and 1H, 14,15N ENDOR spectra are described for the type 1 and type 2 Cu(II) centers of dissimilatory nitrite reductase (NiR) from Alcaligenes xylosoxidans. The study was carried out on preparations of NiR containing both type 1 and type 2 Cu sites, and also on preparations of lower activity which contained essentially only type 1 Cu centers. This has enabled ENDOR studies of type 1 and type 2 sites to be carried out largely independently of each other, by appropriate choice of the excitation field. Spectra were recorded both in the absence and presence of nitrite, allowing a clear determination of which of the two types of Cu center constitutes the substrate binding site. The EPR results show large changes in the type 2 site gparallel (which decreases by 0.065) and CuAparallel (which increases by 2.0 mT) while the type 1 site EPR is not affected. In addition, both 1H and 14N ENDOR of the type 2 Cu site undergo considerable changes on addition of nitrite whereas the type 1 Cu site ENDOR is unaffected. Our results clearly demonstrate that nitrite binds to the type 2 copper and that this process significantly perturbs the ligation of this copper by the protein histidine residues. No 15N ENDOR resonances were observed from 15N nitrite. The accessibility of the copper sites to solvent has been studied using 2H2O. The results indicate that nitrite binds to the type 2 Cu by displacing a proton, probably on a water molecule bound to the copper atom.
Alcaligenes↗
Electron-paramagnetic-resonance and magnetic-circular-dichroism studies of the binding of cyanide and thiols to the thiols to the iron-molybdenum cofactor from Klebsiella pneumoniae nitrogenase.
FeMoco, a low-M(r) metal cluster of probable composition Fe7MoS9 complexed with homocitrate, has been extracted with N-methylformamide from the MoFe protein of the nitrogenase enzyme from Klebsiella pneumoniae. The binding of cyanide and thiols to the FeMoco cluster in its paramagnetic S = 3/2 oxidation level has been studied by low-temperature e.p.r. and magnetic-circular-dichroism (m.c.d.) spectroscopies. Cyanide binds to isolated FeMoco at more than one site, and causes changes in the g values form g = 4.6, 3.2, 2.0 to g = 4.29, 3.82, 2.02 E.p.r. competition studies indicate that one cyanide can be displaced by thiolate from one type of site. The form of the low-temperature m.c.d. spectrum is little changed by ligand binding, thus the basic cluster structure remains intact. However, when benzenethiol is bound, a new intense band (lambda 387 nm) is observed, indicating the generation of an increased ligand-to-cluster charge-transfer interaction.
Circular Dichroism↗
Localized hypertrophic neuropathy.
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Adult↗
Aerodynamic estimates of induced anterior orifice openings in human subjects.
This study first examined the accuracy of pressure-flow area estimates of experimental openings in anterior palatal obturators of three adult subjects. Second, we evaluated pressure-flow measures of the same experimental openings using a model. Results indicated that percent error in orifice estimates was slightly higher for induced openings in human subjects (13%) versus those in the model (11%). Results for our human subjects were similar to those reported by previous investigators.
Aged↗
Purification and characterization of the dissimilatory nitrite reductase from Alcaligenes xylosoxidans subsp. xylosoxidans (N.C.I.M.B. 11015): evidence for the presence of both type 1 and type 2 copper centres.
Dissimilatory nitrite reductase was isolated from extracts of Alcaligenes xylosoxidans subsp. xylosoxidans (N.C.I.M.B. 11015), after activation of crude extracts by the addition of copper(II) sulphate. The enzyme was purified by a combination of (NH4)2SO4 fractionation and cationic-exchange chromatography to 93% homogeneity as judged by SDS/PAGE. SDS/PAGE and spray m.s. showed that the enzyme had a subunit M(r) of 36.5 kDa. The copper content was 3.5 +/- 0.8 Cu atoms/trimer of M(r) 109,500. E.p.r. spectroscopy of nitrite reductase as isolated showed that both type 1 (g parallel = 2.208, A parallel = 6.3 mT) and type 2 (g parallel = 2.298, A parallel = 14.2 mT) Cu centres were present, in contrast with published data [Masuko, Iwasaki, Sakurai, Suzuki and Nakahara (1984) J. Biochem. (Tokyo) 96, 447-454], where only type 1 copper centres were reported. Our preparations had a specific activity of 150-300 mumol of NO2- reduced/min per mg of protein, 6-12-fold higher than reported previously. As isolated, the oxidized form of our preparations of the enzyme showed absorption maxima in the visible region at 460, 593 and 770 nm. The ratio of the absorption bands at 460 nm and 593 nm resulted in this protein having a strong blue colour, in contrast with the green colour of other purified copper-containing nitrite reductases. We conclude that, in contrast with previous reports, this 'blue' nitrite reductase requires both type 1 and type 2 copper centres for optimal activity.
Alcaligenes↗
X-ray scattering using synchrotron radiation shows nitrite reductase from Achromobacter xylosoxidans to be a trimer in solution.
We demonstrate here the applicability of X-ray scattering for studying molecular conformation of multimeric proteins in solution by using synchrotron radiation to extend the range of data collection to include medium angles (ca. 3-4 degrees). We have been able to define the solution structure of the dissimilatory nitrite reductase of Achromobacter xylosoxidans (AxNiR), an enzyme for which there are conflicting reports as to the nature of its multimeric structure. Quantitative interpretation of the X-ray scattering profile, based on a modeling study using the high-resolution crystal structure data for the nitrite reductase from the related organism Achromobacter cycloclastes (AcNiR), provides a detailed model for the trimeric structure of AxNiR in solution. Sedimentation equilibrium centrifugation gave an M(r) of 103,000, consistent with such a trimeric structure.
Alcaligenes↗
Energy transduction by nitrogenase: binding of MgADP to the MoFe protein is dependent on the oxidation state of the iron-sulphur 'P' clusters.
Hydrolysis of MgATP to MgADP is essential for nitrogenase action. There is good evidence for binding of both nucleotides to the Fe protein of nitrogenase, but data indicating their binding to the MoFe protein have been controversial [see Miller and Eady (1989) Biochem. J. 263, 725-729]. The binding of MgADP to the MoFe protein of nitrogenase of Klebsiella pneumoniae was investigated by non-equilibrium gel-filtration column methods. No binding of MgADP to the dithionite-reduced protein could be detected. Treatment of the MoFe protein with phenosafranine [midpoint potential (Em) -270 mV] did not affect the activity, and oxidized the 'P' clusters but not the iron-molybdenum cofactor (FeMoco) centres. This oxidized species bound 3.9 mol of MgADP with a binding pattern characteristic of low rates of ligand dissociation. These observations suggest that the variability in published data on nucleotide binding to the MoFe protein is related to poor control of the protein oxidation level. Our data, coupled with the observation that 'P' clusters become oxidized during reduction of N2 [Lowe, Fisher and Thorneley (1993) Biochem. J., in the press], led us to propose that the ADP binding sites are transiently filled during enzyme turnover by hydrolysis of ATP originally bound to the Fe protein, and that hydrolysis occurs on a bridging site on the MoFe-Fe-protein complex.
Adenosine Diphosphate↗
Peripheral neuropathies associated with monoclonal proteins.
Peripheral neuropathies associated with monoclonal proteins have received considerable attention as a clinically important group of chronic late-onset neuropathies. When a monoclonal protein is found in patients with peripheral neuropathy of unknown cause, as occurs in 10% of such cases, usually no associated disease is discovered; hence MGUS. Less often, disorders such as multiple myeloma, AL amyloidosis, Waldenström's macroglobulinemia, osteosclerotic myeloma, and lymphoma are found. Demyelinating neuropathies associated with MGUS of all classes, but particularly IgM, Waldenström's macroglobulinemia, and osteosclerotic myeloma typically follow an indolently progressive course, and frequently respond to treatments aimed at interfering with putative underlying immune mechanisms. By contrast, axonal neuropathies associated with MGUS, multiple myeloma, and AL amyloidosis have generally shown no response to therapy. Recently, IgM monoclonal and polyclonal antibodies directed against human peripheral nerve antigens including MAG and various glycolipids such as GM1 ganglioside have been found in patients with specific neuropathy syndromes. Anti-MAG antibodies occur in predominantly sensory demyelinating neuropathies, whereas elevated titers of anti-GM1 ganglioside antibodies are associated with lower motor neuron syndromes with multifocal motor conduction block. Although the evidence for autoimmune mechanisms in some monoclonal protein-associated neuropathies is mounting, a causal connection between monoclonal proteins and these neurologic syndromes has yet to be established.
Amyloidosis↗
Regulation of renal hemodynamics after protein feeding: effects of proximal and distal diuretics.
The purpose of these studies was to compare the effects of proximally and distally acting diuretics on the renal hemodynamic response to protein feeding to determine the importance of the proximal tubule in postprandial renal vasodilation. In chronically instrumented conscious dogs, a meat meal (10 g/kg raw beef) caused glomerular filtration rate (GFR) to increase from 63 +/- 5 to 87 +/- 10 ml/min and effective renal plasma flow (ERPF) to increase from 189 +/- 20 to 249 +/- 20 ml/min, while plasma alpha-amino nitrogen levels rose from 4.0 +/- 0.1 to 6.8 +/- 0.4 mg/dl. Administration of amiloride (0.2 mg/kg + 0.003 mg.kg-1.min-1) or potassium canrenoate (1.76 mg/kg + 1.76 mg.kg-1.h-1), diuretics that act in the distal tubule, had no effect on the renal hemodynamic responses to a meat meal. However, the normal renal hemodynamic responses to protein feeding were abolished during administration of a diuretic that acts in the proximal tubule, acetazolamide (20 mg/kg + 20 mg.kg-1.h-1), although plasma alpha-amino nitrogen levels increased after the meat meal in all experiments. These data suggest that normal proximal tubular sodium reabsorptive function is necessary for acute protein-stimulated renal vasodilation and are consistent with the hypothesis that a tubuloglomerular feedback mechanism may mediate postprandial renal vasodilation.
Acetazolamide↗
Component approach for partitioning nasal airway resistance: pharyngeal flap case studies.
Individuals with craniofacial anomalies often have nasal cavity and/or velopharyngeal constriction. The purpose of this clinical report was to illustrate a technique for partitioning nasal airway resistance into its nasal cavity and velopharyngeal components. This information would be helpful in determining intervention to reduce high nasal airway resistance as well as in providing information about the outcome of corrective procedures to establish velopharyngeal competence for speech. Data from two pharyngeal flap patients seen before and after surgery were utilized in this illustration. These case studies illustrate the usefulness of component resistance measures in quantifying nasal airway patency before and after corrective surgery for velopharyngeal function.
Adult↗
A model for multicultural curriculum development in baccalaureate nursing education.
Valuing multiculturalism is essential to the education of professional nurses in order to incorporate knowledge of and respect for cultural values into nursing care. This article briefly examines the definitions of multicultural concepts in nursing curricula. An innovative model for curricular analysis based on a broad operational definition of multiculturalism is described and applied to a baccalaureate upper-division nursing curriculum. Faculty and student interview data are discussed. Results of the examination of course syllabi, materials, textbooks, instructional videos, and clinical experiences are enumerated. Findings include strengths as well as areas of omission, bias, and insensitivity. Implications for faculty development, recommendations for administrative action, and specific curricular changes are outlined. Heightened sensitivity to the value of multiculturalism and the need for lifelong learning on this topic are emphasized.
Attitude of Health Personnel↗
Metalloclusters of the nitrogenases.
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Amino Acid Sequence↗
Subclinical histopathological changes in the oculomotor nerve in diabetes mellitus.
To provide reference values for the oculomotor nerve, for example, fascicular area and myelinated fiber (MF) number and size distribution, in pathological states, and to determine whether oculomotor nerves from diabetic patients without a history of oculomotor palsy have subclinical structural alterations, the morphometric features of 15 control subjects and eight diabetic patients were evaluated at a proximal and a distal level. On average the control nerves had a fascicular area of 2.7 mm2, 22,311 MF, and a bimodal diameter distribution with peaks at approximately 5 to 6 and 10 to 11 microns and a range of 2 to 20 microns. In proximal nerve, glial bundles were found in one-half of the subjects and patients, with a peak of MF sizes that differed from fibers in nonglial areas. The nerves from diabetic patients departed from the nerves from control subjects in the following two respects: changed size distribution, suggesting atrophy of fibers, and microfasciculation of edge fibers in parts of the fascicles in one-half of the patients. We conclude that glial bundles are probably a normal variant. Microfasciculation occurred much more frequently in nerves from diabetic patients and may represent subclinical injury of unknown cause. The alteration in size distribution may reflect the diabetic state and is not necessarily a precursor to diabetic ophthalmoplegia.
Adult↗
Clinical evaluation--continuous real-time intra-arterial blood gas monitoring during anesthesia and surgery by fiber optic sensor.
A clinical evaluation of the clinical utility, techniques of use, durability, accuracy, and potential complications of a newly available system for the continuous real-time, intra-arterial monitoring of arterial blood gas and acid base status (ABG) has been studied (Optex BioSentry System, Optex Biomedical, Incorporated, The Woodlands, Texas, U.S.A.). The system consists of three separate fiber optic channels with contained fluorescent and absorbant chemical analytes imbedded in a single probe and capable of insertion inside of a twenty gauge indwelling arterial catheter (The Optex Optode Sensor), along with an external monitor. The system was utilized during anesthesia and surgery in the care of five informed patients. Constant trend monitoring of all three variables was deemed satisfactory in four of the patients. The fifth sensor was damaged by a surgical assistant while in place and ceased to function. Comparison of Optode sensor readings with standard clinical laboratory ABG analysis was excellent in three uncomplicated patients (pH: bias -0.0183 pH units, precision: 0.0237 pH units; PCO2: bias 3.22 mmHg, precision 2.04 mmHg; PO2: bias -5.94 mmHg, precision 11.74 mmHg). Postoperative study suggested that discrepancies in a fourth patient may have been due to an incorrect 'offset' applied to the Optode sensor yielding a constant error.
Adult↗