Formoterol provides long-lasting protection against exercise-induced bronchospasm.

BACKGROUND: Patients with exercise-induced bronchospasm (EIB) may benefit from a prophylactic beta2-adrenergic agonist that combines rapid onset with long duration of action. OBJECTIVE: To compare the protective effect against EIB of a single inhaled dose of formoterol powder delivered via the Aerolizer inhaler (Novartis Pharmaceuticals, East Hanover, NJ) with the effect of placebo and albuterol. METHODS: Eighteen patients with EIB were randomized to treatment in a double-blind, placebo-controlled, four-way, crossover study. Seventeen patients completed all four crossover periods. Each patient received in random sequence a single dose of formoterol (12 or 24 microg), albuterol (180 microg), or placebo at intervals of 5 +/- 2 days. Pulmonary function measurements were taken before and after exercise challenge tests (ECTs) at 15 minutes postdosing and at 4, 8, and 12 hours postdosing. RESULTS: Both doses of formoterol produced significantly greater protection against EIB, compared with placebo, at all timepoints (P < or = 0.016). The two doses of formoterol were not significantly different from one another at any time. Protection against EIB with albuterol was clinically significant only for the 15-minute ECT and was statistically superior to placebo for the 15-minute and 4-hour ECTs. Although formoterol and albuterol exhibited a rapid onset of action, formoterol provided longer-lasting protection over the 12-hour observation period. Rescue medication was used substantially less with either dose of formoterol, compared with albuterol or placebo. All treatments were well tolerated. Two-hour postdosing electrocardiograms and vital signs were unremarkable for all study treatments. CONCLUSION: A single dose of formoterol (12 or 24 microg) provides protection against EIB within 15 minutes of dosing and persists for up to 12 hours. Formoterol is safe and well tolerated.     

The expression and activity of renal nitric oxide synthase and circulating nitric oxide in polycystic kidney disease rats

Nitric oxide (NO) influences tubular fluid and electrolyte transport, and hence possibly also fluid accumulation in renal cysts. The expression and activity of intrarenal constitutive NO synthase (cNOS) [neuronal NOS, nNOS and endothelial NOS, eNOS] and inducible NOS (iNOS) and plasma nitrite/nitrate (PNOx) concentration were assessed in homozygous Han:SPRD polycystic kidney disease (PKD) rats (cy/cy), heterozygous Han:SPRD PKD rats (cy/+), homozygous normal Han:SPRD littermates (+/+) and Sprague Dawley rats (sd). The results showed: 1) nNOS expression was decreased in proximal tubules and thick ascending limbs of the loop of Henle in cy/cy and cy/+ rats compared to +/+ and sd rats (p<0.05). nNOS was weakly expressed in the epithelium of small cysts and unexpressed in epithelium of large cysts. 2) iNOS expression was increased in proximal tubular epithelial cells in cy/+ rats compared to +/+ rats and sd rats (p<0.01). iNOS expression in cyst epithelium was decreased in cy/+ rats (p<0.05) and absent in cy/cy rats. 3) eNOS expression was similar in the endothelium of intrarenal arteries in all groups. 4) The activity of renal cNOS was decreased in cy/cy and cy/+ rats; the activity of iNOS was decreased only in cy/cy rats, with no significant difference among the other three groups. 5) PNOx concentration was higher in cy/cy rats than in the other three groups, and correlated positively with plasma creatinine and urea. In conclusion, NOS expression and activity decreased as cysts developed, suggesting that NO downregulation is involved in the pathogenesis of PKD.     

Humoral Immunity to Dietary Antigens in Atopic Dermatitis

Enzyme-linked immunosorbent assays (ELISA) employing a biotin-avidin amplification step are described for the quantification of human serum IgG antibodies to the dietary antigens ovalbumin (OA) and beta-lactoglobulin (BLG). The analytical quality of these assays was acceptable. Antibodies were measured in 16 patients with mild or moderate atopic dermatitis (AD), in 31 patients with a history of AD, and in closely matched controls. Levels of serum anti-OA antibodies did not differ in patients and controls, whereas anti-BLG antibodies tended to be higher in patients with mild or moderate AD than in controls (P less than 0.05).     

Problems affecting performance of the fluorescent treponemal antibody-absorption test for syphilis.

Immunofluorescent staining of Treponema pallidum was studied to clarify the effect of three factors on the results of the fluorescent treponemal antibody-absorption test: (i) heat inactivation of sera at 56 degrees C for 30 min before testing, (ii) use of multicircle slides, and (iii) tungsten illumination to visualize and assess unstained treponemes on reactive as well as nonreactive smears. It was found that serum inactivation before testing was not necessary for detection of immunoglobin G antibody, but an immunoglobulin M prozone was detected in unheated serum. On multicircle slides, it was demonstrated that a false-positive reaction could be obtained in 30 s at 37 and 25 degrees C if a smear where a nonreactive serum had been placed was crossed by a strongly reactive serum from another circle. Tungsten illumination proved necessary for correct assessment of unstained treponemes on all fluorescent treponemal antibody-aborption test smears, reactive or nonreactive. The possible role of these factors in incorrect fluorescent treponemal antibody-absorption test results is discussed.     

The role of accessory cells and T cell-growth factor in induction of cytotoxic T lymphocytes against herpes simplex virus antigens.

The roles of accessory cells and T cell-growth factor (TCGF) in the in vivo induction of herpes simplex type 1 (HSV) specific cytotoxic lymphocytes (CTL) were evaluated. Spleen cells from animals infected with HSV 4-6 weeks previously were depleted of adherent cells by passage over Sephadex G10. Unlike intact cells, such depleted spleen cells failed to respond by producing H-2 restricted virus-specific CTL upon culture for 5 days with infectious HSV. The CTL response could be restored either by adding normal genetically compatible peritoneal cells as accessory cells or by the addition of TCGF. To obtain optimum restoration accessory cells needed to be added soon after culture initiation but with TCGF addition, partial restoration was evident when added as late as 72 hr after culture. TCGF also permitted intact spleen cells to respond to heat-inactivated virus. The results are interpreted to indicate that accessory cells are essentially required for the presentation of virus to specific helper cells with such cells responding by the production of TCGF. The results also indicate that certain forms of virus may trigger the response of CTL precursors but not the response of helper cells.     

Breakpoint clusters of the PML gene in acute promyelocytic leukemia: Primary structure of the reciprocal products of the PML-RARA gene in a patient with t(15;17)

DNA studies of the translocation t(15;17) in acute promyelocytic leukemia (APL) have shown that the retinoic acid receptor alpha (RARA) gene on chromosome 17 is juxtaposed to the promyelocytic leukemia (PML) gene on chromosome 15. The PML breakpoints have been mapped to 3 clusters: bcr1, bcr2, and bcr3. We have examined the PML breakpoint distribution in a series of 33 Chinese patients with APL Twenty-two patients fell within bcr1, 2 within bcr2, and 9 within bcr3. The primary structure of the reciprocal chromosome translocation joints of one patient and that of their normal counterparts have been determined and compared to those of 2 previously reported cases. These studies revealed possible topoisomerase II cleavage sites close to the breakpoints and suggested implications of DNA attachment sites to nuclear matrix. We propose that these features are relevant to the process of illegitimate recombination generating the translocation. © 1993 Wiley-Liss, Inc.     

Effect of hypertonic sucrose upon the immune bactericidal reaction

This study was performed to determine the mechanism whereby hypertonic sucrose inhibits the immune bactericidal reaction. Other investigators had postulated that the initial attack of complement (C) on the cell wall was followed with lysozyme-containing whole serum by an enzymatic reaction upon the peptidoglycan substrate resulting in cell death. In the absence of serum lysozyme, secondary lethal changes might occur from damage to the cell's inner membrane as a result of osmotic forces in the presence of a defective cell wall. Hypertonic sucrose giving rise to plasmolysis and protection of the inner membrane was presumed to differentially inhibit the immune response mediated by lysozyme-free serum. The experimental results observed in this investigation have indicated, however, that the inhibitory effect of sucrose upon the bactericidal reaction may be explained simply by its anticomplementary effect and not by any effect on the bacterial cell. This view was supported by the following observations: (i) the comparability of the inhibitory effect of sucrose upon the immune hemolytic and bactericidal reactions, (ii) the comparable percentage loss in bactericidal activity of whole serum and lysozyme-free serum resulting from hypertonic sucrose, (iii) bactericidal antibody titrations were relatively unaffected and C titrations markedly inhibited by sucrose, (iv) the inhibitory effect of sucrose on the bactericidal reaction was unaffected by prior growth of the organism in the presence of sucrose, (v) the kinetics of the bactericidal reactivity of lysozyme-free serum in hypertonic sucrose, compared with whole serum, did not reveal a prolonged lag phase with lysozyme-free serum, but simply diminished reactivity at all times. These observations are compatible with the view that the C attack upon the outer surface of gram-negative bacteria, which plays a part in the cell's permeability control, may account for cell death. In this regard, the immune bactericidal reaction is quite comparable to the lysis of red cells or nucleated cells by C despite the lack of overt lysis in bacteria, probably because of their underlying supporting structures.     

Maxi K+ channels co-localised with CFTR in the apical membrane of an exocrine gland acinus: possible involvement in secretion

The primary secretion formed in various exocrine glands has a [K+] 2-5 times that of plasma. In this study we measured the transepithelial flux of 36Cl-, 22Na+ and 42K+ across the frog skin and applied the single-channel patch-clamp technique to the apical membrane of frog skin gland acini to investigate the pathway taken by K+ secreted by the glands. Transepithelial K+ secretion was active and was driven by a larger force than the secretion of Na+. When driving Na+ through the epithelium by clamping the transepithelial potential to 100 mV (apical solution reference), blockers of cellular secretion (apical 5-nitro-2-(3-phenylpropylamino)benzoate or basolateral quinine or furosemide) decreased K+ secretion but left Na+ secretion unaffected. We conclude that K+ follows a transcellular pathway across the epithelium. Patch-clamp analysis of the apical membrane of microdissected gland acini revealed a population of voltage- and calcium-activated K+ channels of the maxi K+ type. In cell-attached patches these channels were activated by membrane potential depolarisation or exposure to prostaglandin E2 and had a permeability of 3.6 +/- 0.3 x 10(-13) cm3 s-1, giving a calculated conductance of 170 pS with 125 mM K+ on both sides of the membrane. In inside-out patches the channels were activated by increasing intracellular [Ca2+] from 10(-7) to 10(-6) M and were blocked by Ba2+ added to the cytoplasmic side. Exposure of inside-out patches containing the maxi K+ channel to ATP on the inside activated cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels, confirming that both channels are co-localised to the apical membrane. We interpret these findings in terms of a model where transepithelial NaCl secretion can be supported in part by an apical K+ conductance.     

Detection of large deletions in the LDL receptor gene with quantitative PCR methods

Background  

Familial Hypercholesterolemia (FH) is a common genetic disease and at the molecular level most often due to mutations in the LDL receptor gene. In genetically heterogeneous populations, major structural rearrangements account for about 5% of patients with LDL receptor gene mutations.