Differences in airway responsiveness to leukotriene D4 in allergic sheep with and without late bronchial responses

Allergic sheep respond to inhaled Ascaris suum antigen with either acute and late bronchial obstructions (dual responders) or only acute bronchoconstriction (acute responders). In this study we tested the hypothesis that one factor which may distinguish between these two populations is the difference in sensitivity to a specific mediator of airway anaphylaxis, leukotriene (LT) D4 (a major component of slow reacting substance of anaphylaxis). We postulated that if the hypothesis was correct then dual responders should demonstrate increased airway responses to inhaled LTD4 and that this increased responsiveness should also be reflected by a more severe response to inhaled antigen. To test this we used animals from both groups with the same degree of non-specific airway responsiveness to carbachol and determined their airway responses to controlled inhalation challenges with synthetic LTD4 and Ascaris suum antigen. Airway responsiveness to carbachol was determined by measuring the change in specific lung resistance (SRL) to increasing concentrations of carbachol aerosol, and then identifying, by linear interpolation, the provocative carbachol concentration which produced a 150% increase (PC150) in SRL. Airway responses to LTD4, and antigen were determined by measuring the percentage change in SRL after a controlled inhalation challenge with either aerosol. Airway responsiveness to carbachol was not different between the two groups. There was, however, a difference (p less than 0.05) in the airway response to the same dose of LTD4 in the two groups. Dual responders showed a 297 +/- 72% increase in SRL as compared to a 90 +/- 13% increase in SRL in the acute responders. Dual responders also showed a greater immediate and more prolonged response to antigen than did acute responders. These results suggest that increased responsiveness to LTD4 may be one factor which may distinguish dual responders from acute responders.     

Activated v-myc and v-ras oncogenes do not transform normal human lymphocytes.

Activated v-myc (pSV v-myc) and v-Ha-ras (GT10) oncogenes were introduced into normal human lymphocytes, NIH 3T3 fibroblasts, B-lymphoblastoid cells, and human epithelial cells, using a reconstituted Sendai virus envelope-mediated gene transfer technique. Efficient transfer of the plasmid in each cell type was demonstrable within 1.5 h of transfection by Southern blotting of extrachromosomal DNA extracts, which unexpectedly revealed that v-myc plasmid DNA was unstable in normal lymphocytes but not in the other cell types. The v-myc plasmid was stabilized when cotransfected into lymphocytes together with v-Ha-ras. The transfected v-Ha-ras plasmid was stable in all the cell types tested. v-myc plasmid expression was clearly detectable by 5 h in all cell types except human lymphocytes. Lymphocytes expressed v-myc when transfected together with v-Ha-ras. Transfected ras oncogene was efficiently expressed in all the cell types tested. Expression of the transfected genes increased at 24 and 48 h after transfection. Even though plasmid stability and expression were achieved in myc-ras-cotransfected lymphocytes, no effects on cellular DNA synthesis or immortalization were observed, in contrast to efficient transformation of NIH 3T3 fibroblasts by the same procedure. Our data suggest that efficient expression of transfected myc and ras oncogenes in normal quiescent human lymphocytes is not sufficient for the induction of cell growth and immortalization.     

Idiotype vaccination leads to the emergence of a stable surface Ig-negative variant of the mouse lymphoma BCL1, with different growth characteristics

Vaccination of mice with tumor-derived idiotypic IgM from the B cell lymphoma, BCL1, induces an anti-idiotypic immune response which suppresses tumor development. One of the mechanisms by which tumor cells can escape attack is by failing to express significant levels of idiotypic immunoglobulin at the cell surface, and a stable variant of this phenotype has been isolated. The variant, termed SNAG 1, continues to synthesize idiotypic IgM, which can be detected in the cytoplasm, but it neither secretes nor expresses IgM on the cell surface (less than 10% of the levels of the original BCL tumor), even though the H and L chains show no gross structural changes. The SNAG 1 cells resemble the parent BCL cells in morphology, in expression of MHC class I and II Ag and in bearing FcR. A significant difference between the BCL lymphoma cells and the variant cells is that the latter fail to respond to LPS by either DNA synthesis or secretion of IgM, suggesting that surface Ig might be required for such a response. The variant has a slower rate of division than the parent tumor both in vitro and in vivo, and a rather different organ distribution. Study of such variants might allow analysis of the mechanisms involved in surface Ig expression and its possible role in tumor cell growth and migration.     

Meeting report: Human fetal tissue transplantation research panel

Summary On September 14 through 16, 1988, a meeting on the use of human fetal tissue in transplantation was held at the National Institutes of Health, Bethesda Maryland, USA. The meeting sponsored by NIH for the Human Fetal Tissue Transplantation Research Panel, a consultant group to the Advisory Committee to the Director. The consultant group was convened to deal with the scientific, judicial and moral questions associated with research involving transplantation of human fetal tissue obtained after induced abortions. The first day of the meeting was devoted to presentations addressing scientific issues. Included among the speakers was Dr. Lars Olson, Professor of Neurobiology, Karolinska Institute, Stockholm, who described the use of transplanted human fetal tissue in the treatment of patients with Parkinkson's disease and Dr. Eugene Redmond, Professor of Psychiatry, Yale University School of Medicine, who showed results of work with transplantation of tissue to correct induced Parkinson-like disease in monkeys. Other speakers addressed the present, past or potential use of fetal tissue in the treatment of diabetes, immune disorders, and other diseases, as well as the use of fetal cells in the production of biologicals. At the conclusion of the meeting the panel did not recommend that research be halted on fetal tissue within the context discussed, although the recommendation of the committee is not binding, and an additional assembly of the panel will probably occur before the final recommendation to an NIH advisory committee is made in November. Other meetings on this subject include a meeting on the use of fetal tissue sponsored by the American Association of Tissue Banks, March 6–7, 1989, in Washington D. C. (Crystal City) and a meeting June 10, 1989, the day before the annual meeting of the Tissue Culture Association, USA, in Orlando, Florida, on fetal cells and ownership of cultured cells and products derived from clinical specimens. Following are statements to the Human Fetal Tissue Transplantation Research Panel presented September 14, 1988, by Dr. David Barnes, Associate Professor of Biochemistry and Biophysics in the Environmental Health Sciences Center at Oregon State University, USA, who was asked to address for the panel recent advances in cell culture related to fetal tissue, and Dr. Robert E. Stevenson, Director of the American Type Culture Collection, President of the Tissue Culture Association, USA, and Chairman of the Committee on Cells and Tumors of the American Association of Tissue Banks.     

Management of asthma in hospital: a prospective audit

In a prospective study of management of asthma in hospital patients with acute asthma admitted to a single hospital over a calendar year were surveyed. Altogether 157 out of 194 admissions (81%) were studied. The patients (16 of whom had been admitted twice and one three times) were interviewed at home about two weeks after discharge, and their hospital records were reviewed. When interviewed an appreciable proportion of patients said that their asthma had been poorly controlled after their discharge from the hospital: 54 reported regular sleep disturbance due to wheeze, 78 tightness of the chest in the morning, and 77 wheeze after climbing one flight of stairs. Patients had been described on admission as having had symptoms of deteriorating asthma for a median of three days. Closer questioning of 71 patients, however, elicited that 50 had had regular symptoms indicating poor control for weeks or months. Most patients did not know how their drugs worked, and many did not have an appropriate plan of action in the event of a further attack. In all the cases studied 114 patients were treated with oral corticosteroids, only 70 had had their previous maintenance treatment increased at the time of discharge, and 107 had a follow up appointment booked for an average of three and a half weeks after discharge.These findings show that undersupervision and undertreatment of patients with asthma are common and not confined to those dying of the condition.     

Dietary intake of calcium and postmenopausal bone loss.

The use of calcium supplements to prevent postmenopausal bone loss and hence osteoporosis is widespread, but the evidence for their efficacy, either alone or in combination with other treatments, is contradictory. Skeletal measurements and dietary intake of calcium were determined in 59 healthy postmenopausal women, most of whom were within five years of the menopause. No correlation was found between current intake of calcium and either total calcium in the body or the density of trabecular or cortical bone in the forearm or vertebral trabecular bone. Dietary intake of calcium did not influence the rate of postmenopausal bone loss in the 54 women who completed 12 months of active or placebo treatment. Even when extremes of calcium intake were examined no difference was found in bone measurements between the women with the highest and lowest intakes. The results of this study suggest that the bone density of women in the early menopause is not influenced by current dietary intake of calcium.     

Effects of heat on cell calcium and inositol lipid metabolism

Hyperthermia causes a large (three-to fivefold) increase in intracellular free calcium ([Ca2+]i) in HA-1 fibroblasts. Increased [Ca2+]i appears initially to be due to release of Ca2+ from an internal store, probably located in the endoplasmic reticulum. A subsequent influx of Ca2+ from the extracellular medium is then observed. These heat-induced changes in Ca2+ homeostasis are correlated with turnover of the phosphoinositides (PI), a class of phospholipids whose metabolism has been shown to regulate Ca2+ in a wide variety of cells (M. J. Berridge and R. F. Irvine, Nature 312, 315 (1984]. Hyperthermia induces rapid release of inositol 1,4,5-trisphosphate (IP3) within 1 min at 45 degrees C; IP3 release precedes the heat-induced rise in [Ca2+]i. IP3 release, a result of phosphatidylinositol 4,5-bisphosphate hydrolysis by phospholipase C, is the initial step in PI turnover. Later accumulation of phosphatidic acid, another metabolite in the PI pathway, is correlated with the delayed, heat-induced influx of 45Ca2+ from the extracellular environment. The data thus indicate that heat-induced changes in Ca2+ homeostasis are correlated with activation of PI turnover. They indicate that this class of lipids may be closely involved in heat-induced changes in cellular Ca2+ homeostasis. Cell Ca2+ appears to be important in some aspects of the cellular response to heat.     

The effect of an orally active leukotriene (LT) D4 antagonist WY-48, 252 on LTD4 and antigen-induced bronchoconstrictions in allergic sheep

In this study we examined the effects of a new orally active leukotriene (LT) D4 receptor antagonist, WY-48,252 (1,1,1-trifluoro-N-[3-(2-quinolinylmethoxy)phenyl]methanesulfonamide), on LTD4-induced bronchoconstriction and antigen-induced early and late responses in allergic sheep. For all studies WY-48,252 10 mg/kg, was administered via intragastric tube 1 h prior to airway challenge. In seven sheep, airway challenge with LTD4 [delivered dose mean +/- SE, 53 +/- 2 micrograms] resulted in an immediate increase in SRL to 600 +/- 18% over baseline. When these same sheep were treated with WY-48,252, airway challenge with LTD4 (delivered dose, 61 +/- 5 micrograms) resulted in only a 220 +/- 50% increase in SRL (p less than 0.05 vs placebo). The drug had no effect on baseline SRL. WY-48,252 was also effective in reducing early responses and blocking late responses to inhaled antigen in allergic sheep (n = 7). In the control trial, airway challenge with Ascaris suum antigen resulted in immediate and late (i.e. 6-8 h) increases in SRL of 499% and 138% over baseline (both responses, p less than 0.05). When these same sheep were pretreated with WY-48,252 the immediate antigen-induced increase in SRL was 171% and the late response was 49% over baseline (both responses p less than 0.05 vs control). These results indicate that WY-48,252 is a LTD4 antagonist in allergic sheep. The ability of this compound to modify antigen-induced early responses and to block antigen-induced late responses suggests that the generation of LTD4 during airway anaphylaxis contributes to both responses.     

Conception rates in repeat-breeders and dairy cattle with unobserved estrus after prostaglandin F(2) alpha and gonadotropin-releasing hormone

In Experiment 1, cows with a history of at least two previous unsuccessful inseminations were allocated to four groups. At the repeated estrus (third or greater service), some of the cows were inseminated according to the a.m.-p.m. rule (Controls, n = 83), or received i.m. 100 mug gonadotropin-releasing hormone (GnRH, n = 32) within 30 sec after insemination. Ovaries of the remaining cows to be treated were palpated during the anticipated ensuing luteal phase to determine the presence of a corpus luteum. Cows found to have luteal tissue received i.m. 25 mg prostaglandin F(2)-alpha (PGF(2)-alpha) and were inseminated after detected estrus or at 72 and 96 h after PGF(2)-alpha in the absence of estrus. Cows given PGF(2)-alpha either received no further treatment (PGF(2)-alpha, n = 40) or were given i.m. 100 mug GnRH (PGF(2)-alpha + GnRH, n = 29) after insemination or at 72 h after PGF(2)-alpha in the absence of estrus. Conception rate of control cows (39%) was similar to that of cows given PGF(2)-alpha (40%) or PGF(2)-alpha + GnRH (43%), but it tended to be lower (P = 0.13) than that of cows given only GnRH at insemination (54%). In Experiment 2, cows with unobserved estrus and diagnosed not pregnant (palpation) were palpated to detect a corpus luteum. Cows with luteal tissue received i.m. PGF(2)-alpha (n = 52) or PGF(2)-alpha + GnRH (n = 45) and were inseminated as described above. Conception rates were similar (39% vs 33%, respectively). In Experiment 3, cows in a large commercial dairy with (n = 93) or without (n = 420) previous reproductive problems were given i.m. 100 mug GnRH after insemination (n = 169) or were left untreated (n = 344) at repeat services (third and fourth services). Treatment with GnRH improved (P < 0.05) conception in normal (47% vs 36%) and abnormal (25% vs 12%) repeat-breeding cows. Treatment with PGF(2)-alpha alone or in conjunction with GnRH failed to further improve conception rates and only delayed intervals to rebreeding when administered during the luteal phase after the repeated estrus. The use of GnRH failed to reduce intervals from treatment to insemination or improve conception in cows with unobserved estrus compared to treatment with PGF(2)-alpha alone.