Comparison of effects of a self management booklet and audiocassette for patients with asthma.

The effects on self management of asthma of a specially prepared book and audiocassette tape with similar contents were observed in a controlled study of 177 patients with asthma in general practice. After a run in period of six months patients were randomly given the book, the tape, both the book and tape, or neither. Patients'' knowledge of the use of drugs, perceptions of their disability, skill in using an inhaler, consumption of drugs, consultations with their general practitioners, morbidity (from patients'' entries on diary cards), and use of the educational material were measured. Knowledge about the use of drugs was significantly increased in the groups who received the material after three months and persisted after 12 months. Patients who had been given the tape or the book and tape increased their scores of knowledge of drugs more than patients given the book alone. Patients in all groups given the material considered that their disability was reduced. There were no other significant changes. Patients given both the book and the tape preferred the book. Patients with asthma can obtain useful information from such material. The paradoxical result whereby patients learnt more from the tape but preferred the book suggests that a distinction can be made between information that patients need, which may be acquired better from an audiocassette, and information that they want, which may be acquired better from a book.     

Platelet-activating factor in the rabbit uterus during early pregnancy

Platelet-activating factor (PAF) concentrations were low in the non-pregnant, oestrous uterus (mean +/- s.e.m.: 2.2 +/- 1.2 pmol/g, n = 3). However, uterine PAF increased dramatically during pregnancy to a maximum of 37.8 +/- 4.90 pmol/g (n = 7) on Day 5. By Day 7, PAF concentrations in the uteri of pregnant rabbits had returned to levels similar to those found at oestrus. In contrast, uterine PAF in pseudopregnant rabbits peaked at 30.6 +/- 2.8 pmol/g (n = 8) on Day 4, declined to 20.5 +/- 2.4 pmol/g (n = 8) on Day 5 and then remained at that concentration through Day 7. Uterine PAF co-migrated with synthetic PAF (1-O-hexadecyl-2-acetyl-sn-glycero-phosphocholine) in both thin-layer and normal-phase high-performance liquid chromatography. PAF activity in the uterus during pregnancy and pseudopregnancy was found almost exclusively in the endometrium; little or no PAF was found in myometrium, uterine flushings or blastocysts. While no PAF was detected in blastocysts on Days 5 and 6 of pregnancy, the presence of the embryo appears to modulate biosynthesis and/or degradation of PAF by the uterus, since PAF decreased significantly in uterine tissue apposed to the implanting embryo (but not in similar areas between such attachment sites). Increased concentrations of PAF in the preimplantation rabbit uterus followed by a dramatic decrease on the day of blastocyst attachment suggest that this potent inflammatory autacoid may play a vital role in implantation.     

L-tryptophan inhibits formation of mutagens during cooking of meat and in laboratory models

The formation of mutagens and carcinogens of the 2-amino-3-methylimidazo[4,5-f]quinoline and -quinoxaline type, formed during the frying or broiling of meats and in liquid-reflux laboratory models, was inhibited by L-tryptophan in a dose-dependent fashion. Addition of 75 mg (1.04 mg/cm2 surface area) of L-tryptophan per side in a sauce to ground beef patties prior to cooking significantly blocked the formation of mutagens observed in control patties treated identically with sauce but without L-tryptophan. The sauce itself did not have a significant inhibitory effect. When a mixture of 35 mM glucose, 70 mM glycine, and 70 mM creatinine in diethylene glycol-water (95:5) was heated in a liquid-reflux model for 2 h at 150 degrees C, the addition of 1.75-105 mM L-tryptophan gave a dose-related inhibition of mutagen formation, that reached 100% inhibition with 105 mM L-tryptophan.     

Relation of changes in amount and type of dietary fat to fecapentaenes in premenopausal women

Correlation studies suggest that fecal mutagenicity is increased in groups eating high-fat diets, the same groups who are often found to have high colorectal cancer incidence and mortality. The fecapentaenes are the best characterized class of fecal mutagens, but the relationship of dietary fat intake to the excretion of these potent genotoxins is unknown. We studied the effect of changes in amount and type of dietary fat on fecapentaene levels in 31 premenopausal women 20-40 years of age who participated in a controlled feeding study. After a pre-diet free-living period lasting 1 menstrual cycle, women were placed on a high-fat (40% energy from fat) diet for 4 menstrual cycles and then switched to a low-fat (20% energy from fat) diet for an additional 4 menstrual cycles. One-half the subjects were maintained throughout the study at a ratio of polyunsaturated-to-saturated fatty acids (P/S ratio) of 1.0, the other half at 0.3; body weight was constant. All meals during the controlled diet periods were prepared at the Human Study Facility of the Beltsville Human Nutrition Research Center. Fecapentaene and fecapentaene precursor levels were measured in acetone extracts from 3-day pooled stool samples collected during the study. No differences in fecapentaene or precursor levels were observed between the high- and low-fat diets at either P/S ratio. Fecapentaene and precursor levels were higher while on controlled diets than during the pre-diet free-living period, and levels declined again in the post-diet free-living period. We conclude that dietary fat has no significant effect on fecapentaene or precursor levels in acetone extracts of stool in premenopausal women. The effect of other dietary or non-dietary factors on fecapentaenes remains unknown.     

Experimental determination of forces transmitted through the patello-femoral joint

Tensions in the quadriceps tendon and infrapatellar ligament were measured as a function of flexion angle in eight cadaver knees using a load cell of a materials tester to determine the quadriceps force and a spring balance to quantify the patellar tendon force. The ratio between the tensions in the quadriceps tendon and the patellar tendon (FQ/FP) ranged from 1.55 at 70 degrees of flexion to 0.86 at 10 degrees of flexion. The patello-femoral joint reaction (PFJR) force for extension against resistance was maximal at 60 degrees. No change in the quadriceps force required to extend the knee occurred with changes of the Q-angle of +/- 5 degrees. This study demonstrates that FQ does not equal FP as several authors have reported (Bandi, 1972; Barry, 1979; Ficat and Hungerford, 1977; Hungerford and Barry, 1979; Reilly and Martens, 1972; Smidt, 1973). Furthermore, the difference in FQ and FP influences both the magnitude and direction of PFJR. Studies that assess the influence of surgical procedures which alter the patello-femoral joint or the extensor mechanism must take these differences into account.     

The relationship between glucose transport and the production of succinoglucan exopolysaccharide by Agrobacterium radiobacter

Agrobacterium radiobacter NCIB 11883 was grown in ammonia-limited continuous culture at low dilution rate with glucose as the carbon source. Under these conditions the organism produced an extracellular succinoglucan polysaccharide and transported glucose using the same periplasmic glucose-binding proteins (GBP1 and GBP2) as during glucose-limited growth. Transition from glucose- to ammonia-limited growth was accompanied by a very rapid decrease in glucose uptake capacity, whereas the glucose-binding proteins were diluted out much more slowly (t1/2 approximately 1 h and 14 h respectively). Although the rate of glucose uptake and the concentrations of GBP1 and GBP2 were much lower during ammonia limitation, the activities of enzymes involved in the early stages of glucose metabolism and in the production of succinoglucan precursors were essentially unchanged. Glucose transport was also investigated in two new strains of A. radiobacter which had been isolated following prolonged growth under glucose limitation. Glucose uptake by strain AR18 was significantly less repressed during ammonia limitation compared with either the original parent strain or strain AR9, and this was reflected both in its relatively high concentration of GBP1 and in its significantly higher rate of succinoglucan synthesis. Flux control analysis using 6-chloro-6-deoxy-D-glucose as an inhibitor of glucose transport showed that the latter was a major kinetic control point for succinoglucan production. It is concluded that glucose uptake by A. radiobacter, particularly via the GBP1-dependent system, is only moderately repressed during ammonia-limited growth and that the organism avoids the potentially deleterious effects of accumulating excess glucose by converting the surplus into succinoglucan.     

The superoxide generating system of B cell lines. Structural homology with the phagocytic oxidase and triggering via surface Ig

EBV-transformed B lymphocyte cell lines (EBV-BLCL) produce superoxide after stimulation with phorbol ester, a capacity unique among nonmyeloid cells. The superoxide producing system of EBV-BLCL (B cell oxidase) was compared with the phagocytic NADPH-oxidase and the relationship of the capacity to produce superoxide to the presence of the EBV-genome was analyzed. The two EBV-transformed B cell lines F1 and HELL generated superoxide in response to PMA (2.3 nmol/10(6) F1 cells x 1 h and 6.27 nmol/10(6) HELL cells x 1 h with 1 microgram/ml of PMA), whereas no superoxide release was detected with the EBV-positive Burkitt lymphoma line WIL-2 and the EBV-negative plasmocytoma line U-266. Also, F1 and HELL showed lucigenin-dependent chemiluminescence (CL) after PMA-treatment, whereas no CL responses were detected from WIL-2 or U-266. Further, F1 and HELL cells contained a low potential cytochrome b-245 (10.9 and 61.0 pmol/mg protein, respectively) and also a 45 kDa diphenylene-iodonium (DPI)-binding peptide, both components of the phagocytic NADPH-oxidase. In contrast, neither the cytochrome b-245 nor the 45 kDa DPI-binding peptide were detected in WIL-2 and U-266. In addition, DPI inhibited O2- production by PMA-stimulated EBV-BLCL and polymorphonuclear granulocytes. Further, F1 line cells showed superoxide dismutase-inhibitable lucigenin-dependent CL when triggered by protein A-bearing staphylococci (Cowan strain I) or by a mAb directed against human IgG in the presence of solid-phase goat anti-mouse-Ig antibody. From a panel of eight EBV-BLCL, only five responded with CL when exposed to protein A-bearing staphylococci, whereas all showed CL when treated with phorbol ester. Inasmuch as all eight EBV-BLCL possessed surface Ig and a "functional" oxidase, their differential response to cross-linking of surface Ig may be determined by differences in signal transduction. Superoxide production by EBV-BLCL appears thus related to expression of an electron transport chain structurally homologous, if not identical, with the "phagocytic" NADPH-oxidase. Apparently, the presence of EBV-genome in B cell lines does not per se lead to expression of this oxidase. This suggests that nontransformed B cells may, at a certain differentiation stage, also express a superoxide-generating chain. From the finding of stimulation of superoxide production of EBV-BLCL via surface Ig it appears possible that also Ag may be able to trigger such B cells to production of superoxide which might have an important role in the physiology of B cells.     

25-Hydroxylation of vitamin D3 in the human hepatoma cell lines Hep G2 and Hep 3B

Two human hepatoma cell lines, Hep G2 and Hep 3B, were screened for vitamin D3-25-hydroxylase enzyme activity by incubation with radioactive vitamin D3. A compound co-chromatographing with 25-OH-D3 was synthesized in both cell lines but its rate of synthesis was tenfold greater in Hep 3B than in Hep G2 cells. The identity of the compound was confirmed by comparing its chromatographic properties with authentic 25-OH-D3 on three different high pressure liquid chromatography systems. Its production was suppressed by adding fetal calf serum (10%), lipoprotein-deficient fetal calf serum, or pure vitamin D-binding globulin to the medium. The mechanism of action of these plasma proteins appears to involve retardation of uptake of the substrate. These two cell lines offer considerable potential as defined in vitro models for studying the effects of physiological factors on the 25-hydroxylation of vitamin D3.