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Biomedical subjects

L D Hudson

Publications and source records attributed to L D Hudson.

At least 127 records · Page 7Linked to original sources
PubMed1986

Cloning and expression of a viral phosphoprotein: structure suggests vesicular stomatitis virus NS may function by mimicking an RNA template.

The phosphoprotein (NS) gene from the Indiana serotype of vesicular stomatitis virus (VSV; Mudd-Summers strain) was cloned and sequenced. The NS gene encodes a protein of 265 amino acids which was expressed from a simian virus 40 vector in COS cells. The post-translational modification characteristic of viral NS, the extensive phosphorylation of a cluster of serine and threonine residues, was also evident in recombinant NS protein. The NS gene displays a property common to the phosphoprotein genes of negative-strand RNA viruses: the phosphoprotein mRNA has a second open reading frame (ORF) which could encode a small (7500 mol. wt.) protein. Both measles virus and Sendai virus employ the second ORF of their phosphoprotein gene, and the resultant proteins have an amino acid composition similar to that predicted for the VSV ORF. Comparison of phosphoproteins from different VSV strains revealed two conserved domains that we propose are critical for the function of NS in transcription and replication.

Animals↗
PubMed1986

Macular amyloidosis: treatment with ultraviolet B.

Macular amyloidosis, a variant of lichen amyloidosus, is an uncommon cutaneous eruption that presents with moderate to severe pruritus associated with areas of hyperpigmentation. Effective modalities for the treatment of this condition have been lacking. A case of macular amyloidosis is reported in which successful management of pruritus was obtained using ultraviolet B (UVB) therapy. Mechanisms of UVB action in this condition are discussed.

Aged↗
PubMed1985

Distribution of ventilation and perfusion during positive end-expiratory pressure in the adult respiratory distress syndrome.

The response of respiratory gas exchange to incremental increases in positive end-expiratory pressure (PEEP) was studied in patients with the adult respiratory distress syndrome (ARDS). Fifty total changes in PEEP were studied in 19 PEEP trials performed in 16 patients. The initial patterns of ventilation-perfusion distribution as measured by the multiple inert gas elimination technique showed a large shunt flow (32 +/- 14% of total cardiac output), which was accompanied in half of the patients by perfusion to a region of low ventilation-perfusion ratio (VA/Q ratio less than 0.1). In 17 PEEP trials, there was an improvement in PaO2 (increase in PaO2 greater than 10 mmHg over control value) with at least one level of PEEP tested. In the 38 PEEP increments in these trials where PaO2 did improve, there was either a reduction in shunt alone, a reduction in ventilation-perfusion regions alone, or a redistribution in blood flow from shunt to regions of low or normal ventilation-perfusion ratio. In the increments where no increase was observed in PaO2, this reduction in blood flow to shunt or low VA/Q regions did not occur. In some instances, there was an increase in ventilation to unperfused alveoli and evidence of high ventilation-perfusion ratio (VA/Q greater than 10) as the level of PEEP increased. Because patients had an adequate pulmonary artery wedge pressure at the start of the PEEP trial (mean wedge pressure, 12.8 +/- 1.5 mmHg) improvements in oxygenation could usually be attained with only mild decreases in cardiac output.

Adult↗
PubMed1985

Extracellular matrix in normal and fibrotic human lungs.

Polyclonal affinity-purified antibodies to human collagen types I, III, and IV, and laminin were used to compare the extracellular matrix (ECM) in 10 normal and 32 abnormal lungs by indirect immunofluorescence. In normal lungs, type IV collagen and laminin codistributed in a uniform linear pattern along the epithelial and endothelial basement membranes. Type III collagen was found within the alveolar septa and interstitium in an interrupted ribbonlike pattern and was aggregated at the entrance rings of the alveoli. Type I collagen was distributed irregularly within the alveolar wall and was less prominent than type III collagen. In patients with pulmonary disease not characterized by interstitial fibrosis (n = 15), the distribution of ECM components studied was essentially normal. In pulmonary disease in which interstitial fibrosis was the characteristic feature, such as idiopathic pulmonary fibrosis (IPF) and adult respiratory distress syndrome (ARDS) (n = 17), collagen types I and III accumulated in the expanded interstitium. Type III collagen was initially predominant in the thickened alveolar septa and interstitium, whereas type I collagen appeared to be the principal collagen at later stages in the disease course. The basement membrane was disrupted early in the disease course with invasion of the alveolar spaces by interstitial collagens similar in type to those present in the adjacent interstitium.

Adult↗
PubMed1985

Causes of mortality in patients with the adult respiratory distress syndrome.

This study analyzed the factors causing and contributing to death in patients with the adult respiratory distress syndrome (ARDS). Two hundred seven patients were prospectively identified as being at risk for development of ARDS. Forty-seven patients developed ARDS, and the remaining 160 patients were used as a comparison control group. The severity of dysfunction in 8 organ systems and the presence of sepsis syndrome were determined by chart review after discharge or death. Sepsis syndrome was specifically defined by signs and laboratory tests reflecting infection or inflammation plus evidence of a deleterious systemic effect (hypotension, reduced systemic vascular resistance, or unexplained metabolic acidosis). Mortality was 68% in the ARDS group compared to 34% in the control group (p less than 0.005). Only 16% (5 of 32) of deaths in the ARDS group were from irreversible respiratory failure. Most deaths in the first 3 days after entry into the study could be attributed to the underlying illness or injury. The majority of late deaths were related to sepsis syndrome. Of the 22 patients with ARDS who died after 3 days, 16 (73%) met our criteria for sepsis syndrome. There was a sixfold increase in sepsis syndrome after ARDS compared with that in the control group (p less than 0.001). When sepsis syndrome preceded the ARDS, the abdomen was the predominant source, but when sepsis syndrome occurred after the onset of ARDS there was usually a pulmonary source. Our findings indicate that sepsis syndrome, rather than respiratory failure, is the leading cause of death in patients with ARDS.

Abdomen↗
PubMed1985

Does intermittent mandatory ventilation correct respiratory alkalosis in patients receiving assisted mechanical ventilation?

One of the claimed advantages of intermittent mandatory ventilation (IMV) over assisted mechanical ventilation (AMV) (assist-control) is the avoidance or correction of acute respiratory alkalosis, ostensibly by allowing patients to achieve normal alveolar ventilation (VA) and PaCO2 through the function of an intact ventilatory drive. However, although respiratory alkalosis in patients being hyperventilated with controlled mechanical ventilation (CMV) can be corrected by a change to IMV, CMV is seldom appropriate for patients with acute respiratory failure, and whether IMV affects respiratory alkalosis in patients triggering the ventilator in the AMV mode has not previously been tested. We studied 26 patients with acute respiratory alkalosis (pH greater than or equal to 7.48) while receiving AMV. Measurements of arterial blood gases and CO2 production (VCO2), and calculation of VA, were performed after 30 min of AMV, repeated after 30 min of IMV at a mandatory rate one half the previous AMV rate, and then repeated again 30 min after a return to the original AMV settings. Mean arterial pH decreased slightly from 7.51 during AMV to 7.48 during IMV, and returned to 7.51 on resumption of AMV (p less than 0.05 for both changes); corresponding mean values for PaCO2 were 28.6, 29.7, and 27.5 mmHg, respectively. These changes were related to an increase in VCO2 during IMV as compared with AMV (p less than 0.05), without a significant alteration in VA. When the mandatory rate was further reduced during IMV from one half to one fourth the prior, triggered AMV rate in 10 patients, no additional reduction in pH occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Comparison of the effects of labetalol and hydrochlorothiazide on the ventilatory function of hypertensive patients with asthma and propranolol sensitivity.

Previous studies have shown that labetalol, a new alpha- and beta-adrenergic antagonist, is relatively safe for the treatment of hypertension in patients with chronic obstructive pulmonary disease (COPD). This multicenter study was designed to evaluate its effects in hypertensive patients with asthma and propranolol sensitivity. Hypertension was successfully controlled in 18 of 21 patients who received labetalol in increasing doses, up to 1,200 mg/day. The decrease in mean FEV1 (1.5 percent) two hours after the highest dose of labetalol was not statistically significant, although there was a gradual decline in mean baseline FEV1 during the four-week treatment period. Antihypertensive agents other than adrenergic antagonists should be considered for the management of hypertension in patients with asthma, especially those with marked reversibility of airflow. If treatment with beta-adrenergic antagonists is indicated, labetalol is recommended over other currently available agents.

Adolescent↗
PubMed1985

Design of the intensive care unit from a monitoring point of view.

In the initial stage of the planning of an intensive care unit, the problems and goals should be identified, solutions to problems developed, and one solution or overall plan selected. At this point, input from all personnel who work in or contribute to care or services in the ICU should be sought and carefully considered. Once this has been done, decisions on specific design features can be made. The overall function of the unit should be kept in mind, and all design decisions should facilitate observation of the patients, surveillance of physiological monitoring, delivery of routine and emergency interventions, and recording of patient care information.

Hospital Design and Construction↗
PubMed1985

Erythema annulare centrifugum: an unusual case due to hydroxychloroquine sulfate.

Erythema annulare centrifugum presents as a cutaneous hypersensitivity to diverse causes including fungal and yeast infections, parasitic infestations, drugs, and, rarely, occult malignancies. A prolonged case of erythema annulare centrifugum secondary to the use of hydroxychloroquine sulfate is presented. The prolonged time needed for clearing after discontinuation of the medication is thought to result from the melanocyte-binding characteristics of the drug.

Drug Eruptions↗
PubMed1984

Early application of positive end-expiratory pressure in patients at risk for the adult respiratory-distress syndrome.

Previous studies have suggested that the early application of positive end-expiratory pressure (PEEP) reduces the incidence of the adult respiratory-distress syndrome. We randomly assigned 92 patients with a known risk for this syndrome to receive mechanical ventilation either without PEEP (control) or with early PEEP at 8 cm H2O. These therapies continued for 72 hours unless respiratory distress developed or arterial oxygen tension was above 140 (fractional inspired oxygen concentration, 0.5) at 24 hours or later and remained at that level after removal of PEEP. The study was designed to have an 80 per cent probability of detecting a 60 per cent reduction in the incidence of the syndrome. The treatment groups were comparable in age, severity of injury, number and type of risk factors for adult respiratory-distress syndrome, and initial oxygenation. The syndrome developed in 11 of 44 patients given early PEEP (25 per cent) and in 13 of 48 control patients (27 per cent). The incidence of atelectasis, pneumonia, and barotrauma was the same in both groups, as was mortality. We found that the early application of PEEP at 8 cm H2O in high-risk patients had no effect on the incidence of the adult respiratory-distress syndrome or other, associated complications.

Adolescent↗
PubMed1984

Influence of head-dependent positions on lung volume and oxygen saturation in chronic air-flow obstruction.

We investigated the influence of head-dependent positions upon functional residual capacity (FRC) and arterial oxygen saturation in 25 patients with clinically stable chronic air-flow obstruction and 25 normal subjects. Lung volume was measured by gas dilution in normal subjects and by plethysmography in patients with chronic obstructive pulmonary disease (COPD). Arterial oxygen saturation was determined by ear oximetry. In normal subjects, sitting FRC declined by 29.9% when a horizontal-supine posture was assumed, but underwent little further change as the supine subject was tilted head-downward to -25 degrees. Lateral decubitus positions caused declines from sitting FRC of 17.1% at 0 degrees, and 27.4% at -25 degrees. In contrast, patients with COPD experienced negligible changes in lung volume as position was varied. The mean falls from sitting FRC were 3.5% and 1.9% in the 0 degree supine and 0 degree lateral decubitus postures, respectively, and little further volume loss occurred in head-dependency. Eight patients actually increased FRC when recumbent. Positional lung volume changes measured by gas dilution exceeded those measured by plethysmography, suggesting that increased air trapping helped to maintain FRC as position was altered. Patients with COPD did not desaturate in any position tested. We conclude that patients with advanced COPD conserve lung volume and do not desaturate when tipped into head-dependent positions. Reduction of FRC is unlikely to contribute to the hypoxemia or dyspnea previously reported to occur in these patients during chest physiotherapy.

Female↗
PubMed1984

Subcutaneous and mediastinal emphysema. Pathophysiology, diagnosis, and management.

Subcutaneous emphysema and pneumomediastinum occur frequently in critically ill patients in association with blunt or penetrating trauma, soft-tissue infections, or any condition that creates a gradient between intra-alveolar and perivascular interstitial pressures. A continuum of fascial planes connects cervical soft tissues with the medlastinum and retroperitoneum, permitting aberrant air arising in any one of these areas to spread elsewhere. Diagnosis is made in the appropriate clinical setting by careful physical examination and inspection of the chest roentgenogram. While the presence of air in subcutaneous or mediastinal tissue is not dangerous in itself, prompt recognition of the underlying cause is essential. Certain trauma-related causes may require surgical intervention, but the routine use of chest tubes tracheostomy, or mediastinal drains is not recommended.

Emphysema↗
PubMed1984

Pulmonary function of marrow transplant patients. I. Effects of marrow infusion, acute graft-versus-host disease, and interstitial pneumonitis.

The pulmonary function of patients receiving marrow transplants was studied during a two-year period. The 81 patients studied before transplantation showed a slight reduction in average lung volumes and diffusing capacity (DLCO). Studies were repeated within 48 h after marrow infusion to look for evidence of fat embolism syndrome. There was no change in the DLCO, but there was a 4% decrease in the lung volumes. Sixty-three patients (20 with aplastic anemia, 43 with hematologic malignancies) completed studies on admission and every other week during hospitalization (mean of six studies per patient). When categorized by diagnosis or conditioning regimen (including with and without total body irradiation), no differences were seen. The patients developing interstitial pneumonitis (IP) had restrictive ventilatory changes and decreases in the DLCO. The patients not developing IP remained unchanged. The patients developing IP averaged a 20% decrease in the DLCO before the clinical diagnosis of pneumonia, but a decrease in the DLCO lacked specificity for predicting occurrence of IP. Among 18 patients developing graft-versus-host disease, there was no evidence of air-flow obstruction. We conclude that patients developing IP have restrictive ventilatory changes, but in the absence of complicating IP, the marrow transplant regimen (including marrow infusion and total body irradiation) leaves pulmonary function largely unchanged.

Adolescent↗
PubMed1984

Measurement of plasma fibronectin in patients who develop the adult respiratory distress syndrome.

Depletion of plasma fibronectin has been observed in certain clinical conditions predisposing to the adult respiratory distress syndrome and has been associated with cardiopulmonary dysfunction in experimental lung injury. We evaluated prospectively the relationship between plasma fibronectin concentration and the development of the adult respiratory distress syndrome in patients known to be at high risk. Although plasma fibronectin levels in participants at study entry were lower in this population (mean 258 +/- 132 micrograms/ml) than in normal volunteers (461 +/- 127 micrograms/ml, p less than 0.0025), there was no difference between patients who subsequently developed the adult distress syndrome (mean 255 +/- 149 micrograms/ml) and those with similar illness or injury who did not develop the syndrome (260 +/- 126 micrograms/ml). Fibronectin concentration was not further depressed even after development of adult respiratory distress syndrome and did not correlate with degree of pulmonary dysfunction. These data suggest that fibronectin depletion is not an important determinant of respiratory failure in humans. Patients with sepsis syndrome had significantly lower plasma fibronectin levels than those without sepsis (187 +/- 119 micrograms/ml vs. 273 +/- 131 micrograms/ml, p less than 0.05), suggesting a possible role for fibronectin in the pathogenesis of sepsis.

Adult↗
PubMed1983

Monitoring hemodynamics in the critically ill.

Intelligent, safe patient management based on hemodynamic monitoring requires that the right measurements be made, that the data so generated be accurate, and that the clinician's judgment and understanding of their use be appropriate. This article discusses the catheterization of systemic and pulmonary arteries, with an emphasis on the purposes to be served by monitoring rather than on specific measurements, techniques, or devices.

Cardiac Catheterization↗