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Biomedical subjects

F Lewis

Publications and source records attributed to F Lewis.

At least 55 records · Page 3Linked to original sources
PubMed1988

Gene transfer from targeted liposomes to specific lymphoid cells by electroporation.

Large unilamellar liposomes, coated with protein A and encapsulating the gene that confers resistance to mycophenolic acid, were used as a model system to demonstrate gene transfer into specific lymphoid cells. Protein A, which selectively recognizes mouse IgG2a antibodies, was coupled to liposomes to target them specifically to defined cell types coated with IgG2a antibody. Protein A-coated liposomes bound human B lymphoblastoid cells preincubated with a mouse IgG2a anti-HLA monoclonal antibody but failed to adhere to cells challenged with an irrelevant (anti-H-2) antibody of the same isotype or to cells incubated in the absence of antibody. Transfection of target cells bound to protein A-coated liposomes was achieved by electroporation. This step was essential since only electroporated cells survived in a selective medium containing mycophenolic acid. Transfection efficiency with electroporation and targeted liposomes was as efficient as conventional procedures that used unencapsulated plasmids free in solution but, in the latter case, cell selectivity is not possible. This technique provides a methodology for introducing defined biological macromolecules into specific cell types.

Animals↗
PubMed1987

Demonstration of human papillomavirus types in paraffin processed tissue from human ano-genital lesions by in-situ DNA hybridisation.

A sensitive in situ hybridization technique for the demonstration of human papillomavirus (HPV) employing a biotin-streptavidin polyalkaline phosphatase complex has been successfully applied to formalin-fixed, paraffin processed tissue obtained from a selected series of patients with ano-genital lesions. Benign condylomata from males and females showed the presence of HPV 6 and 11. Two cases of vulval intraepithelial neoplasia showed HPV 16. Four cases of squamous carcinoma of the anal canal also showed HPV 16 in the tumour or in the adjacent pre-invasive neoplastic epithelium. A case of malignant transformation in a cervical condyloma was associated with HPV 6 and 11. This technique permits the retrospective evaluation of routinely processed material thus widening the investigative spectrum for HPV.

Adolescent↗
PubMed1985

Differential diagnosis of appendicitis and pelvic inflammatory disease. A prospective analysis.

Diagnosis of the cause of lower abdominal pain in women may be difficult because appendicitis and pelvic inflammatory disease often present similarly. In a prospective study of 118 women, we found that several criteria are useful in establishing this differential. These include (1) duration of symptoms, (2) the presence of nausea, vomiting or both, (3) a history of venereal disease, (4) cervical motion tenderness, (5) adnexal tenderness, and (6) isolated peritoneal signs in the right lower quadrant. Although no single finding can define the diagnosis, the history and physical findings reported herein provide a number of criteria which, when taken together, will usually allow a confident diagnosis of either appendicitis or pelvic inflammatory disease to be made. Attention to these items can improve precision in diagnosis and lessen the incidence of unnecessary laparotomy, which carries a well-documented complication rate of 10 to 20 percent.

Adolescent↗
PubMed1984

Differentiation of schistosomes by species, strain, and sex by using cloned DNA markers.

We have detected species, strain, and sex-specific genetic markers for the genus Schistosoma by Southern blot analysis of its DNA using cloned DNA segments of the Schistosoma mansoni ribosomal gene as probes. Restriction analysis of DNA from eight different strains of S. mansoni, from Africa and the Caribbean, revealed that the predominant or major DNA fragment containing the ribosomal gene unit was the same in each but that low copy number or minor fragments containing the gene varied. It was shown that the detection of these minor fragments could serve as the basis for both strain differentiation and the analysis of individual differences within a strain. Analysis of the parents and progeny of a genetic cross revealed sex-linked markers and suggested that these markers are inherited in a Mendelian fashion. DNAs from the species Schistosoma haematobium and Schistosoma japonicum were also analyzed. Differences in the length of the major repeating unit of the ribosomal gene served to distinguish each species. Furthermore, an array of minor bands was detected in each species, suggesting that strains of S. haematobium and S. japonicum could be differentiated in the same manner as S. mansoni strains.

Animals↗
PubMed1982

Measurement of extravascular lung water in dogs using the thermal-green dye indicator dilution method.

The measurement of extravascular lung water by a double-indicator dilution technique using cold indocyanine green dye was evaluated in dogs. Pulmonary edema was induced in 11 animals by volume overload; 12 animals served as controls. For each measurement, the two indicators (cold dye) were injected into the superior vena cava and detected in the femoral artery. The extravascular thermal volume was calculated using the mean transit times of the two indicator curves. Pretermination measurements of extravascular thermal volume correlated closely with standard gravimetric analysis of pulmonary extravascular tissue weight (EVTV - 1.15 PEW + 2.1 ml/kg, n = 21, r = 0.97, P less than 0.001; where EVTV = extravascular thermal volume and PEW = pulmonary extravascular tissue weight). Throughout the experiment, the arterial oxygen tension and alveolar-arterial oxygen tension gradient, correlated poorly with EVTV (linear correlation: r = 0.47, 0.45, respectively). The intrapulmonary shunt correlated better with EVTV (r = 0.72). Nonlinear correlation of EVTV with intravascular pressures (left ventricular filling pressures, colloid oncotic pressures, and the pulmonary artery occlusion pressure-colloid oncotic pressure gradient) were more significant than linear relationships. The critical pressures at which lung water rapidly increased in this model occurred at left ventricular filling pressures of 22-27 mmHg and at pulmonary artery occlusion pressure-colloid oncotic pressure gradients of 25-30 mmHg. The thermal dye technique appears to provide an accurate measurement of lung water changes in this pressure edema model.

Animals↗
PubMed1981

Adenovirus eye infections in an Australian city, 1972-9.

A number of adenovirus serotypes have been associated with both sporadic cases and outbreaks of conjunctivitis and pharyngoconjunctival fever but only adenovirus type 8 and adenovirus type 19 have been responsible for wide-spread epidemic kerato-conjunctivitis. In Melbourne, Australia, in the past eight years these two serotypes have been prevalent, resulting in an outbreak of adenovirus type 8 kerato-conjunctivitis in 1976-7 followed by adenovirus type 19 kerato-conjunctivitis in 1978-9. During these two periods of peak incidence, 53 cases of adenovirus type 8 and 43 cases of adenovirus type 19 kerato-conjunctivitis were confirmed by isolation.

Adenoviridae Infections↗
PubMed1981

Effect of cardiac output on extravascular lung water.

Extravascular lung water (EVLW) and cardiac output (CO) were determined in 21 mongrel dogs using the thermal-green dye double indicator dilution technique. In 12 of the animals the renal vessels were ligated bilaterally to increase peripheral resistance and reduce cardiac output without altering actual EVLW. Measurements before and after renal pedicle ligation revealed an average 47 per cent decrease in cardiac output with an 11 per cent increase in measured lung water. In the remaining nine animals an external arteriovenous fistula was constructed to reduce afterload and increase cardiac output. In the baseline state, opening the fistula caused a 63 per cent increase in cardiac output with a simultaneous five per cent decrease in measured EVLW. This second group of animals was then given intravenous acid sufficient to cause 30-50 per cent increases in EVLW. Measurements of EVLW and CO with the fistula open and closed were continued for three hours. The inverse relation between cardiac output and EVLW continued. The results of these experiments show that cardiac output does exert a small effect on the measurement of EVLW.

Animals↗
PubMed1977

Bacteriology of necrotizing fasciitis.

Sixteen patients with necrotizing fasciitis were observed under clinical and laboratory conditions for collection, preservation, and culture that permitted optimal retrieval of anaerobes. The clinical observations of necrosis of fascia, subcutaneous fat and skin with thrombosis of the microvasculature, and absence of myonecrosis were clearly apparent in these patients. Two clear-cut groups of culture and gram stain results were found, suggesting that the clinical entity of necrotizing fasciitis can occur after infection by different infecting organisms. The cultivation of Streptococcus pyogenes (group A), either alone or in combination with staphylococcus, in three patients conforms to the culture results found by Meleney [1] in his original description.

Bacteria↗