PubMed Health⌕ Search

Biomedical subjects

L Tate

Publications and source records attributed to L Tate.

8 recordsLinked to original sources
PubMed1995

Bronchial epithelial cells regulate fibroblast proliferation.

Chronic bronchitis frequently leads to irreversible airway obstruction. Alteration of airway architecture with abnormal airway connective tissue is thought to play an important role in this process. We hypothesized that the epithelial cells that line the airways modulate the development of peribronchial fibrosis and fixed airway obstruction by directing fibroblast proliferation. To assess this, we examined stimulatory activities for human lung fibroblast proliferation in bovine bronchial epithelial cell-conditioned medium. The conditioned medium stimulated the proliferation of fibroblasts in a serum-free culture system in a concentration-dependent manner. The fibroblast growth stimulatory activity was heterogenous, with molecular masses of > 50 and approximately 10 kDa. Bronchial epithelial cell-conditioned medium also contained fibroblast growth inhibitory factors, including both transforming growth factor (TGF)-beta and, based on indomethacin sensitivity, cyclooxygenase products. TGF-beta appeared to contribute to the morphological change of fibroblasts induced by the conditioned medium. Co-culture of human lung fibroblasts with bronchial epithelial cells resulted in a stimulation of fibroblast proliferation. In summary, airway epithelial cells appear to regulate fibroblast proliferation and may play a role in peribronchial fibrosis in chronic bronchitis.

Animals↗
PubMed1995

Cigarette smoke inhibits lung fibroblast proliferation and chemotaxis.

Cigarette smoking is the most clearly recognized cause of pulmonary emphysema. Since loss of lung tissue, which characterizes emphysema, represents a balance between injury and repair, we hypothesized that cigarette smoke might contribute to the development of emphysema by inhibiting fibroblast proliferation and migration. To evaluate this, we examined the effect of cigarette smoke extract (CSE) on the proliferation and migration of human lung fibroblasts in vitro. CSE inhibited fibroblast proliferation and migration at noncytotoxic concentrations. When CSE was treated to remove volatile components, it showed less inhibitory activity on fibroblast proliferation. Therefore, we also examined acrolein and acetaldehyde, which are volatile components of cigarette smoke, Micromolar concentrations of acrolein and millimolar concentrations of acetaldehyde induced significant inhibition of fibroblast proliferation. In contrast, removal of volatile components did not eliminate the inhibitory activity of CSE for fibroblast migration, although acetaldehyde and acrolein alone were also capable of inhibiting chemotaxis. Cigarette smoke-induced inhibition of fibroblast proliferation and migration may impair lung repair following lung injury, and may thus contribute to the development of pulmonary emphysema.

Acetaldehyde↗
PubMed1995

Modulation of fibroblast type I collagen and fibronectin production by bovine bronchial epithelial cells.

To elucidate bronchial epithelial cell (BEC)-fibroblast interactions with regard to extracellular matrix production, bovine BECs were cultured, and conditioned media were assayed for their effects on fibroblast extracellular matrix production. Bovine BECs were prepared by protease digestion and grown in serum-free medium. When confluent, 48-h conditioned medium (CM) was collected and added to confluent human fetal lung fibroblasts (HFL-1) with 10 micrograms/ml ascorbic acid every other day. Type I collagen and fibronectin production from fibroblasts were quantified by enzyme-linked immunosorbent assay. Fifty percent BEC CM caused an increase in type I collagen (582 +/- 92 pg/10(3) cells/h versus 220 +/- 42, P < 0.001) and in fibronectin (1,422 +/- 60 pg/10(3) cells/h versus 360 +/- 24, P < 0.001) production after 4 days. These observations were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography in HFL-1 cultures labeled with [14C]proline. Dose-dependent stimulation was observed in response to BEC CM. Stimulation of macromolecule release was accompanied by increased steady-state fibronectin and alpha 1 (I) collagen mRNA levels. Sephadex G-150 column chromatography of BEC CM revealed two distinct peaks of activity at approximate molecular weights of 25 kD and > 66 kD. Transforming growth factor beta (TGF-beta)-neutralizing antibody blocked the activity of both peaks, suggesting that TGF-beta produced by the epithelial cells may drive fibroblast matrix production and that a TGF-beta binding substance may be present, or that TGF-beta aggregation may occur. Because some partially purified preparations had increased stimulatory activity compared to crude supernatants, potential inhibitors of matrix production were also sought.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Providing continuity in a "firm" case management system.

Four general medicine units were divided into two "firms" to improve patient outcomes and ensure continuity of care. All members remain part of their firm for as long as they are employed. The nurse case managers remain constant in both inpatient and outpatient settings and coordinate discharge planning.

Case Management↗
PubMed1989

Narcolepsy mimicking suicidal carbon monoxide poisoning.

We present a case of narcolepsy mimicking suicidal carbon monoxide poisoning. The signs and symptoms of narcolepsy in this previously undiagnosed man were initially missed, which emphasizes the importance of extracting a detailed history of a decedent's behavior prior to his or her death. Narcoleptics are often involved in motor vehicle accidents. This report again demonstrates that narcolepsy and driving don't mix, even when the vehicle is stationary. We also briefly review the various sleep disorders.

Carbon Monoxide Poisoning↗
PubMed1983

Two fatal bicyclist injuries from extended rear view mirrors.

Rear view mirrors mounted on the sides of vans and small trucks may extend beyond the sides of the vehicles and pose a hazard to other road users. Case reports of two bicyclists fatally injured by extended rear view mirrors of small trucks are presented.

Accidents, Traffic↗
PubMed1983

Fatal injuries to bicyclists: the experience of Dade County, Florida.

Among 173 fatally injured bicyclists, the head or neck was the region most seriously injured in 86%. The frequency of injury to the head and neck region and the frequency of nonsurvivable (AIS 6) injury were highest among the cases aged 16 years or less. Vertebral fractures occurred most often in the highest cervical vertebra (C1) and progressively less often in lower vertebrae. The relationship between vertebral position and fracture likelihood is approximately log linear. Bicyclists with a relatively long time from injury to death tended to be older persons with survivable injuries. They often died from complications (pneumonia, pulmonary embolus) rather than directly from their injuries.

Accidents, Traffic↗