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Biomedical subjects

M A Lewis

Publications and source records attributed to M A Lewis.

At least 199 records · Page 11Linked to original sources
PubMed1988

Pulmonary and peripheral lymph protein clearance during bacteremia after surgery.

An increase in pulmonary transvascular protein clearance is seen in sheep following postoperative bacteremia. We evaluated whether this increased protein clearance is specific for the lung by comparing in sheep the effect of postoperative bacteremia on both pulmonary and prefemoral lymph protein clearance. Fibronectin, implicated as a factor influencing vascular permeability, was also measured. After intravenous infusion of a sublethal dose of 5 x 10(8) live Pseudomonas aeruginosa (n = 10), pulmonary lymph flow (QL) increased 146% (P less than 0.01), and the lung lymph-to-plasma (L/P) total protein concentration ratio increased 21% (P less than 0.05). This resulted in a 208% elevation (P less than 0.01) in lung protein clearance (LPC = QL x L/P). In contrast, peripheral lymph flow and peripheral protein clearance were not altered. After intravenous infusion of a lethal dose of 5 x 10(9) live Pseudomonas (n = 7), QL rose 243-348% (P less than 0.025), whereas the lung L/P remained at base line, resulting in a 240-358% increase in LPC (P less than 0.025). Again, peripheral lymph flow and protein clearance did not increase. Plasma fibronectin declined slightly after low-dose bacterial challenge but decreased (P less than 0.001) 40% by 4-5 h after high-dose bacterial challenge. After both low- and high-dose bacterial challenge, fibronectin in pulmonary lymph increased (P less than 0.05) relative to total protein. In contrast, no change in peripheral lymph fibronectin was seen. Thus, while postoperative bacteremia increased lung protein clearance, it did not increase peripheral protein clearance, suggesting specificity with regard to the microvascular response to bacteremia.

Animals↗
PubMed1987

Evaluation and implementation of self-management programs for children with asthma.

We have reviewed the needs and problems associated with the evaluation and implementation of programs designed to assist children with asthma and their parents to manage the illness. To date, there are several programs that have been evaluated and found to be effective in terms of the objectives and dimensions described. Implementation has presented a larger problem because there are few implementors and because of the major barriers to be overcome by those who would make these programs available to the significant numbers of children and families who would benefit. Unless ways can be found to overcome the medical and reimbursement barriers, asthma self-management programs will not thrive. The growing number of individuals enrolled in some form of health maintenance organization, however, suggests a greater market for asthma self-management programs, under circumstances in which the costs of emergency room use and hospital services must be borne by physicians and hospitals, rather than by their patients.

Asthma↗
PubMed1987

ACT-asthma control y tratamiento para niños: a progress report.

A randomized clinical trial is in progress to evaluate an asthma educational program for Latino children and their parents. The intervention, "ACT-Asma Control y Tratamiento Para Niños," was adapted from ACT for Kids, an asthma self-management program for English-speaking families. Results of a pilot study indicated that socioeconomic status was a critical variable to be considered in the design of such programs. Latino children and parents encounter significant barriers to access and continuity of medical care. Therefore, the intervention was redesigned to include "linkages" using a nurse to reduce barriers and to coordinate care. The lesson plans emphasize concrete, experimental learning experiences, with repetition of key points in each session.

Asthma↗
PubMed1987

The initial effects of the prospective payment system on nursing home patients.

We examined the discharge outcomes and admission characteristics of patients admitted to Southern California skilled nursing facilities (SNFs) for the first time following an episode of hospitalization in 1980, 1982-83 (all pre-prospective payment system), and all admissions during July through September 1984 (post-prospective payment). The proportion of patients covered by Medicare on admission was 18 per cent in 1980, 36 per cent in 1982-83, and 57 per cent in 1984. For patients discharged within 30-60 days to SNFs, in all three time periods more Medicare than non-Medicare patients were bed-bound, had indwelling catheters, and were comatose. There were only modest case-mix differences between the groups and no changes over time in discharge outcomes, including the proportion dying in the SNF, or being returned to a hospital. The time-related changes that were found preceded the implementation of the diagnosis related group (DRG) based prospective payment system.

Aged↗
PubMed1987

Magnetic resonance imaging of the posterior fossa in ocular motility disorders--four case studies.

The superiority of magnetic resonance imaging (MRI) of the posterior fossa over x-ray computed tomography is demonstrated by four patients with neuro-ophthalmologic disorders. Advantages of this technique include lack of ionizing radiation, direct multiplanar imaging, increased sensitivity to pathology, increased tissue contrast, and no known adverse effects. It is concluded that MR, when available, should be the imaging modality of choice in patients with neuro-ophthalmologic disorders of suspected brainstem origin.

Adolescent↗
PubMed1986

Quantitative bacteriology of acute dento-alveolar abscesses.

A qualitative and quantitative bacteriological study was performed on pus specimens obtained by needle aspiration of 50 acute dento-alveolar abscesses. Most samples contained a mixture of species (average 3.3); 20 (40%) of the abscesses contained anaerobes alone, 3 (6%) contained facultative anaerobes only and the remaining 27 (54%) contained mixtures of both types of bacteria, with anaerobes predominating. In total, 166 bacterial strains were isolated, 75% of which were strictly anaerobic; the most common species were Peptococcus spp, Bacteroides oralis and B. melaninogenicus. Among facultative anaerobes, Streptococcus milleri was particularly common. The mean concentration of bacteria in each abscess was 10(6.9 +/- 0.2). The mean concentration of anaerobic bacteria was 10(6.2 +/- 0.1) and of facultatively anaerobic bacteria 10(5.7 +/- 0.2).

Adult↗
PubMed1986

Transient neonatal Behcet's disease.

A term neonate with a transient form of Behcet's disease is described. The clinical and immunological features are detailed. As healing of the severe ulceration in this condition gives rise to scarring and cosmetic deformity recognition is important. Therapeutic intervention with corticosteroids is recommended after diagnosis.

Behcet Syndrome↗
PubMed1985

Identification and characterization of leukotriene D4 receptors in adult and fetal human lung.

Leukotriene D4 (LTD4) receptors were identified and characterized in adult and fetal human lung membranes. Macroscopically normal adult lung tissue was selected from seventeen surgical biopsy specimens, and twenty-seven fetal lung samples were obtained from therapeutic abortions. Binding assays were performed using pooled adult or fetal human lung membranes at 30 degrees under conditions which prevented metabolism of [3H]LTD4. Specific binding reached equilibrium within 30 min, remained constant for 60 min, was enhanced by Mg2+, and was inhibited by Na+ and guanyl-5'-yl-imidodiphosphate. Computer-assisted analyses of saturation binding data showed a single class of binding sites with similar apparent Kd (0.15 +/- 0.09 and 0.12 +/- 0.003 nM) and Bmax (68 +/- 29 and 62 +/- 14 fmoles/mg protein) values for adult and fetal samples respectively. Competition binding studies with [3H]LTD4 showed the same rank order potency for adult and fetal lung receptors (5S, 6R-LTD4 greater than 5S, 6R-LTD1 greater than 5R, 6S-LTD4 greater than 5S,6R-LTE4 greater than FPL 55712). A comparison of the receptor binding affinities of these compounds with their smooth muscle contractile agonist (pD2) and antagonist (-log[KB]) activities in guinea pig lung and trachea showed a good correlation (r = 0.88), suggesting that the saturable, high-affinity, stereoselective [3H]LTD4 specific binding sites identified in human lung may be physiologically relevant receptor moieties.

Adult↗
PubMed1985

Leukotriene E4 binds specifically to LTD4 receptors in guinea pig lung membranes.

High affinity, stereoselective binding sites for [3H]leukotriene E4 ([3H]LTE4) have been identified and characterized in guinea pig lung membranes. [3H]LTE4 bound to these membranes with a pharmacological specificity identical to that previously observed for the [3H]LTD4 receptor in guinea pig lung. [3H]LTE4 specific binding was selectively inhibited by Na+, enhanced by Ca2+, Mg2+ and Mn2+ and modulated by guanine nucleotides. Scatchard analysis of saturation binding data showed a single class of high affinity and saturable binding sites, with a dissociation constant (Kd) of 0.4 +/- 0.2 nM and a density (Bmax) of 430 +/- 50 fmol/mg membrane protein, similar to values observed for the LTD4 receptor in guinea pig lung. The rank order potency of agonist binding to the [3H]LTE4 binding sites was LTD4 greater than LTE4 much greater than LTC4. These results indicate that [3H]LTE4 binds to [3H]LTD4 receptors and suggests that induction of smooth muscle contraction by LTD4 and LTE4 may be mediated by identical mechanisms and receptors in the guinea pig lung.

Animals↗