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Biomedical subjects

L E Stevens

Publications and source records attributed to L E Stevens.

At least 37 records · Page 2Linked to original sources
PubMed1986

Analysis of chlorhexidine sorption in soft contact lenses by catalytic oxidation of [14C]chlorhexidine and by liquid chromatography.

Two methods are described for the analysis of chlorhexidine sorption in soft contact lenses. The first is an isocratic ion-pairing high-performance liquid chromatographic (HPLC) method with UV detection at 220 nm that allows the determination of chlorhexidine, p-chloroaniline, and other chlorhexidine degradation products in ophthalmic solutions. This procedure had a detection limit of 0.1 ng. The second involves the catalytic oxidation of the lens matrix containing [14C]chlorhexidine to [14C]carbon dioxide and water. The label is then trapped as carbon dioxide in a cocktail and is analyzed by liquid scintillation counting. These methods are sensitive, accurate, and reproducible, and can be used independently or in conjunction for the determination of chlorhexidine sorption in soft contact lenses.

Adsorption↗
PubMed1986

Fibronectin in severe sepsis.

Fibronectin was given in the form of cryoprecipitate of human plasma to patients with severe surgical sepsis in a double blind, prospective and randomized clinical study. Of the 19 patients assigned to the control group receiving no fibronectin, only eight (42 per cent) survived. Of the 12 patients given the cryoprecipitate, nine survived (75 per cent) (p less than 0.05). In the control group, initial serum fibronectin levels were depressed to 121 micrograms per milliliter (normal = 313). The mean values in the blank plasma controls did not increase after 24 hours, with a mean of 122. In contrast, the group treated with cryoprecipitate increased serum fibronectin values after 24 hours to 216 micrograms per milliliter, up from initial values of 161 micrograms per milliliters. Improvements in pulmonary function, serum bilirubin and serum creatinine values were also noted, but the changes fell short of statistical significance. Fibronectin appears to benefit patients in severe surgical sepsis in this study of a relatively small number of patients.

Adult↗
PubMed1983

Gauging the severity of surgical sepsis.

I developed a method for scoring the severity of a septic process, based on deteriorated functions in seven key organ systems of the body. The scoring system is numeric and recognizes that the risk to a patient rises geometrically as organ-system functions deteriorate step by step. The scoring system was validated by reviewing the clinical course of 30 patients with sepsis. Prognosis and hospital stay correlated well with individual scores. The scoring system offered more accurate comparisons in clinical studies of infected patients and helped follow up a patient with sepsis more accurately.

Humans↗
PubMed1976

Skin and heart allograft prolongation in tilorone-treated rats.

Tilorone is a synthetic amino-alkoxyfluorenone with demonstrated antiviral and antitumor properties. This study gives evidence for immunosuppressive properties of the substance as well. Buffalo rats (AgB6) received skin grafts from rats of the Fischer (AgB1) strain. Control animals rejected in 9.9 +/- 1.1 days, compared to 13.7 +/- 2.3 days for recipients treated with Tilorone. Steroids when combined with Tilorone further prolonged skin allografts to 16.7 +/- 2.6 days. Heart allografts from Fischer (AgB1) and Brown-Norway (AgB3) to Lewis (AgB1) also were performed. In the Fischer to Lewis combination, allograft survival was prolonged from 14.7 +/- 1.0 to 31.0 +/- 3.8 days. In the Brown-Norway to Lewis combination, treated rats rejected in 10.2 +/- 1.4 days versus 6.6 +/- 1.1 days for controls. Increased levels of cytotoxic antibody specific to lymphocytes of the donor strain were noted in Tilorone-treated animals. The mechanism by which Tilorone prolongs allografts may well involve a combination of interferon production and specific suppression of thymus-derived lymphocytes.

Animals↗
PubMed1976

Suppression and reversal of allergic encephalomyelitis in guinea pigs with a non-encephalitogenic analogue of the tryptophan region of the myelin basic protein.

The administration of synthetic peptide S42 leads to suppression and reversal of experimental allergic encephalomyelitis (EAE) induced in guinea pigs by myelin basic protein. Peptide S42 contains a linear sequence of 21 amino acid residues, H-Phe-Ser-Trp-Gln-Lys-Phe-Ser-Trp-Gln-Lys-Phe-Ser-Trp-Gln-Lys-Phe-Ser-Trp-Gln-Lys-Gly-OH, made up of four repeating unit sequences of H-Phe-Ser-Trp-Gln-Lys-OH in addition to a C-terminal glycine. Injected at relatively high doses, peptide S42 is non-encephalitogenic. It induces delayed-type hypersensitivity which is not followed by EAE, and elicits delayed-type hypersensitivity responses in peptide S42, encephalitogenic trytophan peptide, or BP-challenged animals for either of the three antigens. The repeating unit sequence of peptide S42 is analogous to the encephalitogenic tryptophan region of the BP molecules . The sequence homology is responsible for cellular recognition of this antigen by the skin test assay and suggests in vivo interaction between peptide S42 and EAE-inducing cells leading to suppression and reversal of disease.

Animals↗