Evaluation of an Abbreviated Impactor for Fine Particle Fraction (FPF) Determination of Metered Dose Inhalers (MDI)

Abbreviated impactors have been developed recently to allow more rapid evaluation of inhalation products as alternates to the eight-stage Andersen Cascade Impactor (ACI) which has been widely used in the pharmaceutical industry for assessing aerodynamic particle size distribution. In this paper, a two-stage abbreviated impactor, Westech Fine Particle Dose Impactor (WFPD), was used to characterize the aerodynamic particle size of metered dose inhaler (MDI) products, and the results were compared with those obtained using the standard eight-stage ACI. Seven commercial MDI products, with different propellants (chlorofluorocarbon/hydrofluoroalkane) and formulation types (suspension/solution, dry/normal/wet), were tested in this study by both WFPD and ACI. Substantially equivalent measures of fine particle fraction were obtained for most of the tested MDI products, but larger coarse particle fraction and extra-fine particle fraction values were measured from WFPD relative to those measured using the ACI. Use of the WFPD also produced more wall loss than the ACI. Therefore, it is recommended that the system suitability be evaluated on a product-by-product basis to establish substantial equivalency before implementing an abbreviated impactor measurement methodology for routine use in inhaler product characterization.     

Interactions between FSH, estradiol-17β and transforming growth factor-β regulate growth and differentiation in the rat gonad

Estradiol-17β (E₂) is a mitogen in vivo for the proliferation of granulosa cells in the rat ovary. E₂ is synthesized by the preovulatory follicle through a series of gonadotrophin-dependent events: LH stimulates thecal cells to synthesize androgens (androstenedione and testosterone) which are substrates for FSH-induced aromatization to estrogens in granulosa cells. More recently, we have found that transforming growth factor-β (TGF-β) stimulates DNA synthesis in rat granulosa cells in vitro and this effect is augmented by FSH. Since E₂ is a mitogen in vivo and TGF-β is the only known growth factor to stimulate proliferation in vitro, the possible link between the actions of E₂ and TGF-β were examined. E₂ stimulated the secretion of a TGF-β-like factor by rat granulosa cells in culture, and with time DNA synthesis was stimulated. The mitogenic action of E₂ was enhanced in the presence of FSH, and attenuated by a neutralizing antibody to TGF-β. The latter observations have identified TGF-β as the “missing-link” in the mitogenic actions of E₂ on rat granulosa cells. In addition to the growth-promoting actions of TGF-β plus FSH, TGF-β enhanced FSH-induced aromatase activity. Consequently, FSH plus TGF-β stimulates both the proliferation and aromatization capacity of rat granulosa cells. We propose that interactions between FSH, E₂ and TGF-β lead to the exponential increase in serum E₂ levels that occurs during the follicular phase of the cycle. Similarly, FSH stimulates the aromatization of exogenous androgens to estrogen by Sertoli cells isolated from immature rat testes, and there is a correlation between FSH-induced aromatization and mitotic activity. We have shown that FSH plus TGF-β stimulates DNA synthesis in Sertoli cells. Since E₂ increases the secretion of TGF-β by Sertoli cells, interactions between FSH, E₂ and TGF-β may provide the mitogenic stimulus for Sertoli cells during the prepubertal period. In summary, our findings suggest that the estrogen-induced growth of rat granulosa cells is mediated through the production of TGF-β, which acts as an autocrine regulator of proliferation. We also propose that the growth-promoting actions of FSH on Sertoli cells may depend upon a cascade series of events involving estrogens and TGF-β.     

Monoclonal antibody ALD 180: a reagent specific for a human prenatal skeletal muscle myosin isoform

We report the characterization of monoclonal antibody (MAb) ALD 180, prepared against the myosin of slow avian muscle, for studies of human muscle development and disease. With the use of radioimmunoassays, Western immunoblots of native and denatured myosins, and epifluorescent indirect immunocytochemistry, we show that ALD 180 is specific for an epitope in human prenatal skeletal muscle myosin heavy chain (MHC), which is expressed in diminishing abundance in fetal fibers from at least 19-22 weeks' gestation to term and also in regenerating muscle fibers seen in diseased muscles from both children and adults. ALD 180 recognizes an epitope apparently different from those reacting with anti-prenatal human myosin MAb previously described, and therefore affords a complementary reagent for use in future studies of human myosin isoform expression and regulation.     

Sequence Analysis of Tn10 Insertion Sites in a Collection of Escherichia coli Strains Used for Genetic Mapping and Strain Construction

The chromosomal insertion sites of Tn10-containing Escherichia coli strains were amplified by inverse PCR, and the nucleotide sequences of the junctions were determined. In 95 strains analyzed, 88 unique Tn10 positions were determined and matched to the E. coli chromosome sequence. Two gaps in insertion site positions were noted, one including the terminus of DNA replication and another bounded by recombination hot spots RhsA and RhsB.     

A review of biotechnology processes applied for manganese recovery from wastes

The global consumption of manganese is rising due to its growing industrial requirement while the natural reserves of manganese are diminishing at an alarming rate. Consequently, recovery of manganese from metal containing wastes has become highly crucial. Bioleaching of metal from wastes using microbes provides an adequate advantage over the traditional method of recovery. A molecular level understanding of microbial catalyzed manganese recovery is essential for the exploitation of novel microorganisms for similar applications. In current scenario, the application of bioleaching concentrates on cost effective and eco-friendly recovery of precious metals from mining and industrial wastes. This review encompasses the modern improvements in biomining, highlights the comprehensive factors that emphasize the selection of manganese recovery technique, shed insights into spectacular progress in developing molecular based technologies and also identifies the applicability of different models in metal bioremediation which will not only aid in pollution abatement but also in the prevention of occupational health disorder.     

Differentiation of the anterior latissimus dorsi muscle of the chicken examined by anti-myosin monoclonal antibodies

Two new monoclonal antibodies (McAbs), ALD-180 and ALD-88, produced against the myosin of the slow anterior latissimus dorsi (ALD) muscle of the chicken are described. Their specificity for myosin heavy chain (MHC) was established by radioimmunoassay, immunoautoradiography, and immunofluorescence. They were used in conjunction with McAbs MF-14 and MF-30 (which have been characterized previously to be directed against MHC of the fast skeletal muscle) to examine the developmental changes of the chicken ALD muscle. At the 16-day embryonic, early posthatch, and adult stages the ALD muscle fibers differed in their reaction pattern with the McAbs; at the embryonic stage all fibers reacted strongly with ALD-180 and weakly with ALD-88 and MF-30; at the early posthatch stage there was a checkerboard pattern with many fibers not reacting with any of these three McAbs; and at the adult stage all fibers reacted strongly with ALD-180 and ALD-88 and weakly with MF-30. The MF-14 antibody did not react with ALD muscle at any developmental stage. The mature pattern of immunoreactivity of the ALD muscle fibers with the antibodies was established only after 9 weeks posthatch, and during this 9-week period the immunofluorescence changes were nonsynchronous. Based on immunocytochemical evidence of changes in myosin isoform expression, this study clearly demonstrates a distinctive neonatal (early posthatch) stage in the development of the chicken slow muscle.     

A freeze-fracture study of postembryonic differentiation of latissimus dorsi muscles of the chicken

The differentiation of fiber type characteristics in the anterior (ALD) and posterior (PLD) latissimus dorsi muscles is examined by the freeze-fracture technique in 1-, 7- and 30-day-old chicks. Several characteristics of plasma membrane (caveolae, rectilinear arrays, intramembranous particles) and sarcoplasmic reticulum which show fiber type differences in the adult ALD and PLD muscles are compared in the developmental stages. The caveolar density in the ALD fibers is about 20/microns2 at 1 day increasing to about 37/microns2 at 30 days, whereas in the PLD fibers it remains at about 20/microns2 during this period. The distribution of the caveolae in the two muscles is different from the beginning; in the ALD fibers the caveolae are distributed throughout the plasma membrane and in PLD fibers they are patterned into clusters overlying the I band regions. The density of intramembranous particles of 1-day ALD and PLD plasma membranes appears similar, but by 7 days the particle counts in the sarcolemma of the ALD muscle are about twice as numerous as those in the PLD muscle. The rectilinear arrays are virtually absent in the ALD muscle, whereas in the PLD muscle their density is about 10/microns2 at 1 day and about 20/microns2 at 7 days. Already at 1 day posthatching the SR in ALD and PLD fibers has the adult configuration, i.e., an open irregular network in ALD fibers and periodically arranged tubules with triadic expansions in the PLD fibers.(ABSTRACT TRUNCATED AT 250 WORDS)