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Biomedical subjects

C Miller

Publications and source records attributed to C Miller.

At least 469 records · Page 26Linked to original sources
PubMed1990

Elevated tumor necrosis factor alpha production concomitant to elevated prostaglandin E2 production by trauma patients' monocytes.

The level of tumor necrosis factor alpha (TNF alpha), a monokine implicated in mediating septic shock, is elevated in the blood of some patients with sepsis. Monocytes from 11 trauma patients and 11 burn patients were suboptimally stimulated with interferon gamma and muramyl dipeptide, an analogue of bacterial wall products. The patients with sepsis showed significantly greater total TNF alpha levels (secreted in combination with cell-associated) 3 days before septic episodes, as compared with normal controls (32.38 to 2231.76 ng/10(6) monocytes per milliliter, median = 121.03 ng/10(6) monocytes per milliliter; normal control: 0.00 to 18.20 ng/10(6) monocytes per milliliter, median = 5.93 ng/10(6) monocytes per milliliter). Increases in patients' total monocyte TNF alpha levels greater than 30 ng/10(6) monocytes per milliliter correlated with septic episodes. In patients with sepsis, the total monocyte TNF alpha levels were increased despite a concomitant increase in their prostaglandin E2 levels in both stimulated (interferon gamma plus muramyl dipeptide) and unstimulated in vitro assays (9 patients: stimulated prostaglandin E2 range, 30.1 to 123.6 ng/10(6) monocytes per milliliter). Massively elevated monocyte TNF alpha and prostaglandin E2 production occurred simultaneously in patients with sepsis.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

High versus low-dose piracetam in alcohol organic mental disorder: a placebo controlled study.

A marked tendency to increase the dose of piracetam in the treatment of organic mental disorder can be observed in clinical practice. A placebo controlled study comparing two doses (i.e. 6 g and 24 g per die) was performed to evaluate the benefits of high dose piracetam in the treatment of organic mental disorder of chronic alcohol addicts. 60 inpatients participated in the study. Cognitive impairment was verified by various psychological tests on day 0; patients were also evaluated on days 7, 14, 28 and 42 of the trial. While the patients of all three groups showed a significant amelioration during the treatment period, a modest but significant superiority was indicated for the high piracetam dose. There was no difference between the placebo group and the patients receiving low dose piracetam.

Adult↗
PubMed1990

Functional expression of Shaker K+ channels in a baculovirus-infected insect cell line.

We constructed a recombinant baculovirus, A. californica nuclear polyhedrosis virus, containing the Drosophila Shaker H4 K+ channel cDNA under control of the polyhedrin promoter. When infected with this recombinant baculovirus, the cell line Sf9, derived from the army-worm caterpillar S. frugiperda, expresses fully functional Shaker transient K+ currents, as assayed by whole-cell recording. K+ currents begin to appear at about 15 hr after infection, and they continue to increase over the next 3 days. Over the same period of time, a 75 kd band appears on SDS gels stained with Coomassie blue. The identity of this band as a Shaker gene product is confirmed by Western blot analysis using an anti-Shaker antiserum. The 75 kd band accounts for a substantial fraction of the membrane protein in Shaker-infected Sf9 cells. These results give hope that the baculovirus system, which has been used successfully for high-level expression of soluble proteins from higher eukaryotes, may be appropriate for producing large amounts of cloned ion channel proteins as well.

Animals↗
PubMed1990

Nystatin-induced liposome fusion. A versatile approach to ion channel reconstitution into planar bilayers.

A simple method is described for promoting and detecting fusion of liposomes with planar bilayer membranes. Liposomes containing ergosterol are doped with the pore-forming antibiotic nystatin, and the planar bilayer is kept ergosterol-free. Under these conditions, when a transbilayer salt gradient is applied, liposomes added to the high-salt side of the bilayer elicit the appearance of abrupt conductance jumps of 5-300 pS. The increase in conductance is transient, decaying back to baseline on the order of 10 s. Each of these "spikes" represents the fusion of a single liposome with the bilayer, resulting in the simultaneous insertion of many nystatin channels. Relaxation of the conductance back to baseline occurs because ergosterol, required for the integrity of the nystatin pore, diffuses away into the sterol-free planar bilayer after liposome fusion. When Torpedo Cl- channels are reconstituted into liposomes containing ergosterol and nystatin, fusion spikes are observed simultaneously with the appearance of Cl- channels. This method allows the calculation of the density of functional ion channels in a preparation of proteoliposomes containing reconstituted channel protein.

Biophysical Phenomena↗
PubMed1990

Assessment of broadband ultrasound attenuation in the os calcis in vitro.

1. We have examined the relationship between the attenuation of broadband ultrasound in the os calcis in vitro and its bone mineral density measured by quantitative computed tomography and by physical density. 2. Broadband ultrasound attenuation was found to correlate closely with physical density (r = 0.85, P less than 0.0001), but the correlation was less than that observed between quantitative computed tomography and physical density (r = 0.92, P less than 0.0001). Measurements of broadband ultrasound attenuation and quantitative computed tomography were significantly correlated (r = 0.80, P less than 0.0001). 3. Partial correlation analysis showed a significant relationship between broadband ultrasound attenuation and bone density, but when the effect of physical density was taken into account no significant correlation was found between broadband ultrasound attenuation and quantitative computed tomography (r = 0.08, not significant). 4. Broadband ultrasound attenuation in three prospective amputees showed a high degree of concordance between measurements in vivo and in vitro, with no interference by surrounding soft tissues. 5. The correlation between physical density and broadband ultrasound attenuation was independent of quantitative computed tomography, suggesting that the technique measures aspects of density which differ from its mineral density. Broadband ultrasound attenuation holds promise as a reproducible, rapid, radiation-free assessment of skeletal status.

Aged↗
PubMed1990

Broadband ultrasound attenuation in the os calcis: relationship to bone mineral at other skeletal sites.

1. We have examined the relationship between broadband ultrasound attenuation in the os calcis and measurements of bone mineral in the distal forearm and lumbar spine of normal and postmenopausal osteoporotic women. 2. Values of broadband ultrasound attenuation in postmenopausal women with vertebral osteoporotic fractures were significantly lower (35%) than in normal pre- and peri-menopausal women (55.4 +/- 3.8 and 79.6 +/- 0.8 dB/MHz, respectively). 3. Broadband ultrasound attenuation correlated significantly with bone mineral content measured in the distal forearm by single-photon absorptiometry (r = 0.77, P less than 0.0001) and with bone mineral content (r = 0.66, P less than 0.0001) and bone mineral density (r = 0.72, P less than 0.0001) measured in the lumbar spine by dual-photon absorptiometry. 4. Although significant, these correlations are not sufficiently close to be predictive. However, the accuracy of broadband ultrasound attenuation in discriminating between normal subjects and patients with vertebral fracture compared very favourably with direct measurements in the spine by dual-photon absorptiometry. 5. Broadband ultrasound attenuation, but not the other measurements, correlated significantly with age in the osteoporotic patients (r = 0.50, P less than 0.05). 6. These findings may reflect the partial dependence of broadband ultrasound attenuation on the intrinsic trabecular architecture of cancellous bone, the disruption of which contributes to an increase in fracture risk.

Absorptiometry, Photon↗
PubMed1990

Do voltage-dependent K+ channels require Ca2+? A critical test employing a heterologous expression system.

Removal of Ca2+ from the solution bathing neurons is known in many cases to alter the gating properties of voltage-dependent K+ channels and to induce a large, nonselective "leak" conductance. We used a heterologous expression system to test whether the leak conductance observed in neurons is mediated by voltage-dependent K+ channels in an altered, debased conformation. Voltage-dependent K+ channels were expressed in an insect cell line infected with a recombinant baculovirus carrying the cDNA for Drosophila Shaker "A-type" K+ channels. These expressed channels respond to low Ca2+ identically to voltage-dependent K+ channels in native neuronal membranes; upon removal of external Ca2+, Shaker K+ currents disappear and are replaced by a steady, nonselective leak conductance. However, control cells devoid of Shaker channels were free of any voltage-dependent conductances and did not generate a leak when external Ca2+ was removed. These results show that Ca2+ is essential for proper function of voltage-dependent K+ channels and is required to stabilize the native conformations of these membrane proteins.

Animals↗
PubMed1990

Detection of thoracolumbar vertebral body destruction with lateral spine radiography. Part I: Investigation in cadavers.

Despite few and inconclusive studies, radiography is generally believed to be insensitive for detection of osteolytic lesions of the spine. A more detailed investigation was undertaken to study the detectability of laboratory-produced osteolytic lesions in cadaveric thoracolumbar vertebral bodies using conventional lateral radiographs. The radiographs were presented to four radiologists in two sessions over a two month period. In the first session, the films were arranged in a composite of five vertebral bodies, T11 to L3 all from the same spine, in which one contained a lesion and the other four were normal. In the second session, each vertebral body film was presented individually. Area (Az) under the receiver-operating characteristic (ROC) curve was used to measure the performances of readers. Observer detection was similar in the two formats with Az ranging from 0.67 +/- 0.05 to 0.79 +/- 0.04 for the composite film arrangement and 0.57 +/- 0.08 to 0.85 +/- 0.10 for the films of individual vertebral bodies. Lesions were grouped into three relative size categories: 18% to 25%, 26% to 40%, and 41% to 60% of transverse vertebral body diameter. The mean increase in ROC area between the small and large lesions was 0.29 (P less than 0.04) for the composite films and 0.16 (P less than 0.05) for the individual films. In the composite study, all readers showed significant (P less than 0.05) increases in lesion detection in spines reflecting large increases (P less than 0.01) in bone mineral content.(ABSTRACT TRUNCATED AT 250 WORDS)

Cadaver↗
PubMed1990

Detection of thoracolumbar vertebral body destruction with lateral spine radiography. Part II: Clinical investigation with computed tomography.

Conventional radiography in the lateral projection was used to evaluate 25 osteolytic lesions involving vertebral bodies of the thoracolumbar spine. Destruction was calculated as percentages of the maximum transverse diameter and volume of the vertebral body as measured by computed tomography (CT) and the effect of size of lesion on detection was evaluated. Areas (Az) under the receiver-operating characteristic (ROC) curves and the significance of differences were determined from the observations of four radiologists. The mean difference between areas under the ROC curve for lesions involving 32% to 60% of the transverse diameter and for larger lesions of 61% to 93% was 0.12 and significant (P less than 0.05). The effect of the presence of localized loss of vertebral body density, sclerotic bone tissue surrounding the lesion and cortical destruction was evaluated in a second session, in films with lesions the observers scored 4 (probably abnormal) or 5 (definitely abnormal). Cortical destruction was reported to be helpful for detection in 35% of lesions, sclerotic bone surrounding the lesions was helpful in 30%, and a qualitative local decrease in bone density was noted in all lesions. In comparison with the results obtained for the same four observers with experimentally produced lesions in our previous cadaveric study, the clinical lesions of comparable size were not as readily detected. The ROC area for the largest group of clinical lesions (61% to 93%, Az = 0.83 +/- 0.07) was not significantly different from that for a group of smaller cadaveric lesions (41% to 60%, Az = 0.83 +/- 0.05). The smaller clinical lesions (32% to 60%, Az = 0.71 +/- 0.08) were similar in detectability to the experimental lesions of relative diameter 26% to 40% (Az = 0.74 +/- 0.15). Caution should be exercised in the interpretation of conventional radiographs in the lateral projection if there is suspicion of vertebral body destruction.

Adult↗
PubMed1990

Carbamazepine in the prophylaxis of mood disorders.

Alternatives to lithium are desirable in the prophylaxis of affective disorders, especially in patients who are intolerant of or do not respond to that drug. In the past few years the anticonvulsant carbamazepine has been in the foreground of discussion. Twenty-four patients with affective disorders (17 unipolar depressed, six bipolar, and one unipolar manic) were included in a comparative trial of lithium and carbamazepine; 12 had been pretreated with lithium without a satisfactory effect. All patients received carbamazepine (four received it in combination with lithium) over a mean time span of 20.2 months. Eighty percent of the patients improved with carbamazepine treatment. Side effects were infrequent.

Adult↗
PubMed1990

Frequent fallers. Leading groups to identify psychological factors.

CNAs might be good leaders for groups of frequent fallers for several reasons, two of which are that they provide hands-on care and they know the residents well. Residents who fall frequently do not see themselves as persons who fall; they slip, trip, or slide. Single fallers explore ways to prevent another fall. Residents attempting to "do for themselves" and thus maintain their highly-prized independence is a factor contributing to falls. Preservation of autonomy and self-esteem are co-factors. Denial and independence in the faller need to be identified, supported as strengths, and incorporated into a resident's plan of care.

Accident Proneness↗
PubMed1990

Use of laser Doppler flowmetry to determine blood flow in and viability of island axial pattern skin flaps in rabbits.

Perfusion and viability of island axial pattern skin flaps were tested in 37 healthy New Zealand white rabbits, using laser Doppler monitoring of blood flow in the capillary loops and the subpapillary plexus of the dermis. Skin flaps, selected on the basis of the caudal superficial epigastric vein and artery, were lifted and replaced in their original locus after selective occlusion of their vascular pedicles. Subjects were allotted into groups: control group (n = 10); arterial occlusion (n = 7); venous occlusion (n = 10); and arterial and venous occlusion (n = 10). The rabbits were monitored from 48 hours before surgery until euthanasia 48 to 72 hours after replacement of the flap. Flap viability was assessed on a clinical basis, using a comparative scoring method based on a numeric scale. The degree of necrosis in histologic sections was evaluated, using a scoring system. Laser Doppler measurements were obtained on 3 consecutive days before surgery, to establish the normal basal blood flow in the skin. Postsurgical measurements were obtained at 2-hour intervals for the first 8 hours and at 24, 48, and 72 hours after surgery. Measurements of basal blood flow varied significantly (P less than 0.05) from site to site on the surface of individual flaps and over time. When laser Doppler flowmetric (LDF) measurements from 6 sites on a flap were used as a measure of laser Doppler flow for the total flap, there was no significant difference between contralateral flap areas outlined on the abdomen of the rabbits. Temporal variations over 3 days for each rabbit or among rabbits were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗