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Biomedical subjects

F Chapman

Publications and source records attributed to F Chapman.

29 records · Page 2Linked to original sources
PubMed1992

A rapid test for the detection of a B-cell marker (D8/17) in rheumatic fever patients.

A new, rapid blood test for the detection of B-cell markers in patients with rheumatic fever (RF) was applied to 10 patients with RF, 26 of their family members and 14 normal subjects. Three-hundred microliters of blood was obtained by finger-pricking from each subject and submitted to the immunofluorescence technique using three different antibodies, i.e., D8/17 monoclonal ascites antibody, FIRC-conjugated goat anti-mouse IgM (mu chain specific) and phycoerythrin-conjugated murine anti-HLA-DR antibody. D8/17 lymphocytes (green stain) and B-lymphocytes (red stain) were counted using a double-filter microscope. The percentage of positive cells was 20-64% (average 38.5%) in patients, siblings, fathers and mothers, 4.5% in 12 normal controls and 27.5% in the other 2 controls with a family history of RF. In 90% of the families studied, the patients had the highest percentage of positive cells. We conclude that this rapid test can be used as an aid for RF diagnosis and possibly to detect siblings who are at risk to develop the disease.

Adolescent↗
PubMed1991

Sternomastoid muscle twitch maximum relaxation rate: prolonged slowing with fatigue and post-tetanic acceleration.

1. The maximum rate of relaxation of stimulated twitches (twitch maximum relaxation rate) of the sternomastoid muscle was compared with its frequency-force curve (expressed as the ratio of force produced at a stimulation frequency of 20 Hz to that produced at 50 Hz, the 20:50 ratio) before and after fatiguing exercise of the sternomastoid muscle in 10 normal subjects. The mean (+/- SEM) fresh state twitch maximum relaxation rate was 9.51 (+/- 0.64)% force loss/10 ms and the mean (+/- SEM) 20:50 ratio was 73.4 (+/- 2.6)%. 2. The mean twitch maximum relaxation rate fell to 71.5 (+/- 2.2)% of the pre-fatigue value at 2 min after exercise, recovering to 73.1 (+/- 1.6)% by 5 min, 78.4 (+/- 2.34)% by 10 min and 80.6 (+/- 2.70)% by 60-min. The 20:50 ratio fell to 72.3 (+/- 3.56)% of pre-fatigue levels at 10 min after exercise and recovered to 78.8 (+/- 3.16)% by 60 min. There was no significant difference in the percentage falls between the two techniques. 3. Further studies were performed to determine the response of the twitch maximum relaxation rate to a prior brief tetanic stimulus or a brief maximal voluntary contraction of the muscle. Both tetanic stimulation and maximal voluntary contraction accelerated the twitch maximum relaxation rate to over 140% of the fresh state value. Both manoeuvres temporarily returned the slowed twitch maximum relaxation rate after fatiguing exercise back to the fresh state value. 4. The effect of fatiguing exercise on the time course of recovery of quadriceps twitch maximum relaxation rate was also studied in two subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Heterotopic heart transplantation in the rat receiving FK-506 alone or with cyclosporine.

In rats, FK significantly prolonged heterotopic heart graft survival over a wide dose range when given for 2 weeks starting on the day of the operation. Brief courses of FK for one to four days preoperatively, and especially beginning four days postoperatively, allowed long subsequent survival of heart grafts in otherwise untreated recipients. The seeming acceptance of the grafts with postoperative FK treatment was largely but not exclusively donor specific when tested eight days after the last FK dose by second grafts from the same donor v third-party donor grafts. FK in minimally therapeutic doses was synergistic with suboptimal doses of CyA.

Abdomen↗
PubMed1973

Human lymphotoxin: purification and some properties.

Lymphotoxin is secreted by human lymphocytes stimulated with phytohemagglutinin in vitro. Combinations of DEAE-cellulose and Sephadex chromatography, acrylamide gel electrophoresis, and isoelectric focusing were used to purify lymphotoxin 2000- to 4000-fold; 15-25% of the activity has been recovered. Lymphotoxin appears to be a weakly charged molecule(s) of molecular weight about 90,000-100,000 that migrates in Pevikon block electrophoresis as a beta- or alpha2 globulin. It is a discrete molecule(s), because it is completely separable from medium serum proteins and carrier and phytohemagglutinin proteins. Isoelectric-focusing studies indicate that there may be a limited heterogeneity among lymphotoxin molecules.

Cells, Cultured↗
PubMedDate not supplied

Role of air in growth and production of toxic shock syndrome toxin 1 by Staphylococcus aureus in experimental cotton and rayon tampons.

Rayon and cotton fibers of the type used in the manufacture of tampons were extracted for 6 hours in isopropyl alcohol in a soxhlet apparatus to remove all finishes from the fiber surface. The fibers were used to produce experimental tampons of commercial design. Using a syringe method, the tampons were saturated with diluted staphylococci in brain-heart infusion medium and incubated at 37 degrees C. Spent medium was expressed from the tampons and analyzed for growth of staphylococci and production of toxic shock syndrome toxin 1 (TSST-1). Results revealed no statistical difference in the production of TSST-1 by cells grown in rayon or cotton. However, a significant increase in TSST-1 production was observed in tampon cultures when compared with medium controls. When similar experiments were performed with tampons saturated with nitrogen, a significant decrease in TSST-1 production was observed when compared with air-saturated tampons. The results indicate that the oxygen normally present in tampons plays a significant role in modulating the production of TSST-1.

Aerobiosis↗