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Biomedical subjects

F M Laforce

Publications and source records attributed to F M Laforce.

6 recordsLinked to original sources
PubMed1981

Sublethal damage of Escherichia coli by lung lavage.

Incubation of Escherichia coli (10(4)/ml) in cell-free rabbit lung lavage for 30 min at 37 degree C resulted in a 70% reduction in microbial counts on deoxycholate agar but no decrease on blood agar. This effect was not due to agglutination, and the order of exposure was important, i.e., activity was seen only if lavage incubation proceeded deoxycholate treatment. After high speed centrifugation of lung lavage (50,000 X g), activity remained in the supernatant and not in the surfactant pellet, Ultrafiltration of the supernatant (UM to filter) yielded an active ultrafiltrate and an inactive retent. Ultrafiltrate activity was unaffected by heating to 95 degrees C but could be removed by treatment with trypsin or bentonite. Sephadex G-15 fractionation of lyophilized ultrafiltrate yielded three active peptide peaks. Electron photomicrographs showed that incubation with the initial G-15 peak followed by deoxycholate resulted in the disappearance of intracellular material in about half the cells, a finding not seen with deoxycholate or peptide along, and EDTA reversed activity of the G-15 peptide and ultrafiltrate. Rabbit lung lavage contains a complex antimicrobial system that facilitates bile acid destruction of bacteria.

Animals↗
PubMed1979

Campylobacter enteritis associated with unpasteurized milk.

Campylobacter fetus ss. jejuni has recently been recognized as a human enteric pathogen. Laboratory isolation has been hindered by its fastidious nature. Methods for recovery of this organism from stool culture and a specific serologic test are described. An outbreak is reported in which three members of the same family became simultaneously ill with fever, severe abdominal cramps and diarrhea. C. fetus ss. jejuni was recovered from stool specimens from all three. A fourfold increase in serum immunoglobulin G (IgG) titer to this organism was demonstrated in each patient. All three patients had been consuming unpasteurized milk from a cow whose feces were infected with C. fetus ss. jejuni.

Adult↗
PubMed1976

Human oral defenses against gram-negative rods.

Gram-negative rods are unusual pharyngeal isolates in normal man, which suggests the presence of effective oral defense mechanisms against these organisms. To understand this protection better, we studied the elimination of gram-negative rods from the mouth after gargle challenge. Suspensions of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis (108 organisms per ml) were gargled by normal volunteers, and pharyngeal swabs for serial quantitative cultures were taken for 3 hours. Initial swabs yielded approximately 10(5) organisms. Bacterial counts rapidly decreased, and less than 1 per cent of the original inoculum was still recoverable 3 hours later. Studies of tongue, pharynx, and buccal mucosa samples showed the most rapid decrease in buccal mucosa samples and the slowest decrease in tongue swabs. To evaluate physical clearance, gargle challenges were performed using E. coli radiolabeled with technetium-99m. External counts of the oral cavity decreased rapidly, with 21.8, 14.7, 8.9, and 7.8 percent of the initial counts remaining at 30, 60, 120, and 180 min, respectively. Nonpiliated E. coli adhered poorly to buccal epithelial cells in vitro, in contrast to good adherence when piliated strains were tested. Despite these findings, no differences in radiolabel clearance was noted in vivo using piliated and nonpiliated E. coli for gargle challenges. Normal oral defenses against gram-negative rods are highly effective and seem to involve both physical clearance and local bactericidal activity.

Adult↗
PubMed1976

Polymorphonuclear leukocyte inclusions and impaired bacterial killing in patients with Felty's syndrome.

Humoral factors, phagocytosis, bactericidal capability, and ultrastructural morphology of blood polymorphonuclear leukocytes were investigated in 10 patients with Felty's syndrome. Five patients had suffered significant bacterial infections in the past two years while five other patients had not had bacterial infections. The patients with infections had higher concentrations of serum cryoglobulins, and their neutrophils contained immunoglobulin inclusions as seen by immunofluorescent and electron microscopy. Additionally, leukocytes from these patients showed decreased ability to kill Staphylococcus aureus and a minor defect in phagocytosis. There was a generalized subcellular disorganization of these inclusion containing neutrophils and a slower than normal release of lysosomes. Several of the above abnormalities may contribute to an increased susceptibility to bacterial infections in patients with Felty's syndrome.

Adult↗
PubMed1975

Inhibition of leukocyte candidacidal activity by serum from patients with disseminated candidiasis.

The effect of normal serum and serum for seven patients with disseminated candidiasis (DC) on candidacidal activity of normal human neutrophils (PMNL) was studied. PMNL incubated in DC serum had depressed candiacidal activity when compared to studies with normal serum. The candidacidal defect was not related to differences in particle uptake since phagocytic indices were similar with either normal or DC serum. DC serum did not affect PMNL bactericidal activity against Staphylococcus aureus. When Candida albicans (CA) was incubated in either normal or DC sera, washed, and added to PMNL in normal serum, pronounced inhibition of candidacidal activity was seen in all studies with CA previously incubated in DC serum. Dilution of DC serum or absorption of DC serum with heat-killed CA reversed the candidacidal defect. Ultrastructural studies of phagocytized CA demonstrated small ("tight") phagolysosomes and a delay in breakdown of an electron-dense coating on CA previously incubated in DC serum when compared to controls. Inhibition of leukocyte candidacidal activity appeared to be related to high titers of IgG antibodies against CA present in DC serum.

Antibodies, Fungal↗