Morphometric analysis of the adrenal compartments exposed to sustained delivery of androgens.

The role of reproductive and adrenal steroid hormones on the structural and functional capacity of adrenal tissue has not been well investigated. The objective of this investigation was to morphometrically evaluate the effect of testosterone (T), dihydrotestosterone (DHT), and androstenedione (AED) given in a sustained manner, by tricalcium phosphate lysine (TCPL) ceramic capsules, on the adrenals of adult male rats. Sixteen adult male rats were randomly divided into four equal groups. Groups II, III, and I were implanted with TCPL capsules loaded with AED, T, and DHT, respectively. Group IV animals were not implanted, and thus served as the control group. At the end of ninety days post-implantation, the animals were euthanized using standard aseptic surgical techniques. The adrenal glands were harvested and stored in 10% formalin. The tissues were processed, embedded, sectioned and stained with H & E using standard laboratory procedure. Random sections of control and experimental tissues were utilized for morphometric analysis by using Image Pro digital analysis techniques. Data collected were analyzed by means of ANOVA (p < 0.05). Results of this study revealed. (1) There was an increase in the total areas of T treated animals in comparison to the control and other experimental groups, (2) the total lengths of each hormonally treated tissue showed an increase in size of DHT treated tissue verses control, but differences of T and AED compared with control remained insignificant, (3) upon analysis of the zona glomerulosa (Z1) and zona fasciculata (Z2) the data demonstrated a significant increase in animals treated with DHT and AED in comparison to control and T treated animals, (4) finally, statistical analysis performed on measurements of the zona reticularies (Z3) indicated notable increases only in the AED exposed animals. The changes in size of the various tissues may be warranted due to reactions of the steroid hormones with different surface receptors in different layers. However, further investigations are needed, especially longer duration of treatment, to fully hypothesize the exact mechanisms of these hormones on the adrenal glands.

Properties of variant forms of human stem cell factor recombinantly expressed in Escherichia coli.

The gene for human stem cell factor (SCF) encodes a leader sequence followed by 248 amino acids (Martin et al., 1990, Cell 63, 203). Of these 248 amino acids, the first 189 correspond to an extracellular domain and the remainder correspond to a hydrophobic transmembrane domain plus a cytoplasmic domain. A naturally occurring soluble form, released by proteolytic cleavage after amino acid 165, has been described. An alternatively spliced mRNA, lacking the codons for exon 6, has also been described. Since the amino acids encoded by exon 6 include the proteolytic cleavage site, the form expressed from the alternatively spliced mRNA tends to remain membrane-bound. In the present study, we have begun to explore structure/function relationships within the extracellular domain of SCF. Forms beginning at amino acid 1 (after the leader sequence) and ranging from 127 to 189 at the C-terminus have been recombinantly expressed in Escherichia coli and purified. In addition, forms missing the amino acids encoded by exon 6, forms missing up to 10 amino acids from the N-terminus, and forms with disulfide bond alterations have been expressed and purified. The forms have been characterized structurally, as well as functionally, in quantitative cell proliferation and receptor-binding assays. The results indicate that amino acids 1-141 comprise a structural and functional core and allow conclusions about the necessity of each of the two disulfide bonds for structure and function.

Applications of thin layer chromatography, high performance liquid chromatography and mass spectrometry in the fermentation and isolation of the antibiotic nybomycin.

Thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and mass spectrometry (MS) methods have been developed for the analysis of the antibiotic nybomycin, its derivatives deoxynybomycin and nybomycin acetate, during the fermentation and isolation of nybomycin. Using a quantitative HPLC based assay, the time course of nybomycin production (nybomycin titers) in 1000 liter fermentations was determined. Desorption chemical ionization mass spectrometry (DCI/MS) of standard nybomycin samples, fermentation broth samples and purified fractions suggested the co-production of deoxynybomycin which was not reported previously from this organism. TLC and HPLC were used to confirm the presence of deoxynybomycin in the crude extracts of fermentation broths.

Depends on who you ask: what maximizes participation of families in early intervention programs.

This two-part study was a preliminary investigation of the types of procedures that could be useful in maximizing the participation of families in early intervention programs for their special-needs infants, toddlers, and pre-schoolers. In Study 1, 64 professionals in the early intervention field completed a survey that described 29 potential techniques for maximizing participation of families. For each technique, the respondents endorsed whether they employed the procedure, or would if they could. In addition, they rated the expected effectiveness of each procedure. Verbal praise and encouragement were highly rated and almost universally in use, as were various types of written and resource materials. Tangible reinforcement was seldom employed and professional respondents tended to indicate that they did not expect that such techniques would be useful. In Study 2, 29 mothers of high-risk infants and toddlers currently in early intervention rated the same 29 procedures, but were significantly more likely to endorse the use of tangible reinforcers and logistical support. Comparisons among respondents from professional and parent samples were discussed, along with implications of the findings and necessary directions for future research in this area.

Studies on the biosynthesis of the antibiotic crisamicin A and carbon-13 magnetic resonance assignments.

The biosynthesis of crisamicin A, a novel dimeric isochromanequinone antibiotic from Micromonospora purpureochromogenes subsp. halotolerans has been investigated by [1-13C] and [2-13C] labeled acetate precursor feeding experiments. Analysis of the proton noise decoupled and off resonance 13C NMR spectra of 13C enriched and unenriched crisamicin A and their acetate derivatives indicated the biosynthesis via the polyketide pathway, as expected. Further analysis of the enriched spectra allowed the complete assignment of the carbon signals. Of particular interest was the establishment of the linkage between the two monomeric halves of the molecule and determination of the location of the phenolic hydroxyls.

Crisamicin A, a new antibiotic from Micromonospora. I. Taxonomy of the producing strain, fermentation, isolation, physico-chemical characterization and antimicrobial properties.

A microorganism, designated as RV-79-9-101 and now identified as Micromonospora purpureochromogenes subsp. halotolerans, isolated from a mud sample in the Philippines, has been shown to produce a complex of antibiotics called crisamicins. Thin-layer chromatography and bioautography, employing solvent extracts of whole fermentation broths, revealed a minimum of five antimicrobial components. The major biologically-active component of the antibiotic complex, crisamicin A, was obtained in pure form after preparative silica gel column chromatography followed by crystallization. Based on physico-chemical data crisamicin A has been identified as a novel member of the isochromanequinone group of antibiotics. It exhibits excellent in vitro activity against Gram-positive bacteria but little or no activity towards Gram-negative bacteria or fungi.