Analysis of ligase chain reaction products via matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry

A rapid and accurate detection of ligation products generated in ligase chain reactions (LCR) by using matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) is reported. LCR with Pfu DNA ligase was performed with a wild-type template and a template carrying a single point mutation within the Escherichia coli lacI gene as a model system. Starting from about 1 fmol of template DNA the ligation product generated in the positive reactions was analyzed with HPLC and MALDI-TOF-MS, whereby the need of proper sample purification prior to mass spectrometric analysis was demonstrated. A purification procedure with a high potential for automation using streptavidin-coated magnetic particles and ultrafiltration was introduced. Plasmid DNA and short single-stranded oligonucleotides have been used as template. A point mutation could be discriminated from the wild-type template due to the absence or presence of ligation product. This approach allows the rapid-specific detection of template DNA in femtomole amounts and moreover can distinguish between sequence variations in DNA molecules down to point mutations without the need for labeling, gel electrophoresis, membrane transfer, or hybridization procedures.

The rad9 gene of Coprinus cinereus encodes a proline-rich protein required for meiotic chromosome condensation and synapsis

The rad9 gene of Coprinus cinereus is essential for the normal completion of meiosis. We examined surface-spread preparations of wild-type and rad9-1 nuclei from the meiotic stages of karyogamy through metaphase I, and we determined the primary sequence, structure, and meiotic expression of the rad9 gene. In wild-type C. cinereus, karyogamy is followed by condensation and alignment of homologous chromosomes. Condensation and axial core development largely precede synapsis, which often initiates at telomeres. A diffuse diplotene phase coincides with dissolution of the synaptonemal complex, and subsequently chromosomes further condense as the cells progress into metaphase I. In contrast, although karyogamy and nucleolar fusion are apparently normal in rad9-1 basidia, only short stretches of synaptonemal complex form. These correlate with stretches of condensed chromatin, mostly at apparent chromosome ends, and regions of presumptive triple synapsis are numerous. rad9-1 basidia enter the diffuse stage of early diplotene, and then 50% of these cells enter metaphase I by the criteria of nucleolar elimination and at least some chromatin condensation. rad9 gene expression is induced after gamma irradiation and during meiosis. The gene has 27 exons and encodes a predicted protein of 2157 amino acids, with a proline-rich amino terminus.

Analysis of polymerase chain reaction-amplified DNA products by mass spectrometry using matrix-assisted laser desorption and electrospray: current status

Recent advances in molecular biology are making it possible to diagnose genetic diseases and identify pathogens through the analysis of DNA. As clinical applications for molecular diagnosis increase, rapid, reliable methods for determination of DNA size will be needed. Mass spectrometry offers the potential of analyzing amplified DNA quickly and reliably, without the need for gel-based separation and sample labeling steps that are conventionally employed. Both electrospray ionization and matrix-assisted laser desorption/ionization have been evaluated for the size analysis of DNA using both synthetic oligonucleotides and PCR-amplified samples corresponding to bases 1626 to 1701 of the cystic fibrosis transmembrane conductance regulator gene. Both technologies have been demonstrated to have mass range and sensitivity required for the analysis of PCR-amplified DNA in this size range using minimal sample preparation. Steps required to incorporate either ionization technique into a reliable analytical scheme for the rapid, routine analysis of DNA are outlined.

Matrix-assisted laser desorption/ionization mass spectrometry of immobilized duplex DNA probes

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry was used to analyze short DNA duplex probes with one strand immobilized on solid supports (straptavidin-coated magnetic beads or controlled pore glass beads). Only the non-immobilized strand could be detected. Partial denaturation was found when the duplex probes were mixed with 3-hydroxypicolinic acid, ammonium citrate matrix. The strategy has several applications, such as fast DNA sequence analysis and DNA diagnostics.

Rapid genome change in synthetic polyploids of Brassica and its implications for polyploid evolution

Although the evolutionary success of polyploidy in higher plants has been widely recognized, there is virtually no information on how polyploid genomes have evolved after their formation. In this report, we used synthetic polyploids of Brassica as a model system to study genome evolution in the early generations after polyploidization. The initial polyploids we developed were completely homozygous, and thus, no nuclear genome changes were expected in self-fertilized progenies. However, extensive genome change was detected by 89 nuclear DNA clones used as probes. Most genome changes involved loss and/or gain of parental restriction fragments and appearance of novel fragments. Genome changes occurred in each generation from F2 to F5, and the frequency of change was associated with divergence of the diploid parental genomes. Genetic divergence among the derivatives of synthetic polyploids was evident from variation in genome composition and phenotypes. Directional genome changes, possibly influenced by cytoplasmic-nuclear interactions, were observed in one pair of reciprocal synthetics. Our results demonstrate that polyploid species can generate extensive genetic diversity in a short period of time. The occurrence and impact of this process in the evolution of natural polyploids is unknown, but it may have contributed to the success and diversification of many polyploid lineages in both plants and animals.

Lines of murine oligodendroglial precursor cells immortalized by an activated neu tyrosine kinase show distinct degrees of interaction with axons in vitro and in vivo

Replication-defective retroviruses expressing the t-neu oncogene, or a hybrid protein with the neu tyrosine kinase linked to the external region of the human epidermal growth factor receptor (egfr-neu), were used to establish lines of murine oligodendroglial precursor cells. Differentiation of the t-neu lines into myelin-associated glycoprotein (MAG)-positive oligodendrocytes was induced by dibutyryl cAMP, and the egfr-neu line showed limited differentiation in vitro upon withdrawal of epidermal growth factor. Cerebellar granule cell neurons expressed mitogens for the cell lines. Upon transplantation into demyelinated lesions, t-neu line cells engaged with the demyelinated axons whereas the egfr-neu line cells differentiated further and ensheathed the axons. These cell lines thus interact with neurons in vitro and in vivo and can be used as tools to define the molecules involved in different stages of neuron-glia interaction.

Glial cell transplants that are subsequently rejected can be used to influence regeneration of glial cell environments in the CNS

Transplantation of glial cells into demyelinating lesions in CNS offers an experimental approach which allows investigation of the complex interactions that occur between CNS glia, Schwann cells, and axons during remyelination and repair. Earlier studies have shown that 1) transplanted astrocytes are able to prevent Schwann cells from participating in CNS remyelination, but that they are only able to do so with the cooperation of cells of the oligodendrocyte lineage, and 2) transplanted mouse oligodendrocytes can remyelinate rat axons provided their rejection is controlled by immunosuppression. On the basis of these observations, we have been able to prevent the Schwann cell remyelination that normally follows ethidium bromide demyelination in the rat spinal cord by co-transplanting isogeneic astrocytes with a potentially rejectable population of mouse oligodendrocyte lineage cells. Since male mouse cells were used it was possible to demonstrate their presence in immunosuppressed recipients using a mouse Y-chromosome probe by in situ hydridisation. When myelinating mouse cells were rejected by removal of immunosuppression, the demyelinated axons were remyelinated by host oligodendrocytes rather than Schwann cells, whose entry was prevented by the persistence of the transplanted isogeneic astrocytes. The oligodendrocyte remyelination was extensive and rapid, indicating that the inflammation associated with cell rejection did not impede repair. If this host oligodendrocyte remyelination was prevented by local X-irradiation, the lesion consisted of demyelinated axons surrounded by processes from the transplanted astrocytes. By this approach, it was possible to create an environment which resembled the chronic plaques of multiple sclerosis. Thus, these experiments demonstrate that in appropriate circumstances the temporary presence of a population of glial cells can alter the outcome of damage to the CNS.

Nonlinear multivariate image filtering techniques

In this paper, nonlinear multivariate image filtering techniques are proposed to handle color images corrupted by noise. First, we briefly review the principle of reduced ordering (R-ordering) and then define three R-orderings by selecting different central locations. Considering noise attenuation, edge preservation, and detail retention, R-ordering based multivariate filters are designed by combining the R-ordering schemes. To implement color image filtering more effectively, we develop them into a locally adaptive version. The output of the adaptive filter is the closest sample to a central location that is a weighted linear combination of the mean, the marginal median, and the center sample. As a result, we study an adaptive hybrid multivariate (AHM) filter consisting of the mean filter, the marginal median filter, and the identity filter. The performance of the two adaptive filtering techniques is compared with that of some nonadaptive ones. The examples of color image filtering show that the adaptive multivariate image filtering gives a rather good performance improvement.

Revisit of MALDI for small proteins

Matrix-assisted laser desorption/ionization (MALDI) was used for several small proteins (such as insulin) and for peptides. It was found that the detection efficiencies of MALDI for the insulin B chain and the insulin A chain are drastically different. Similar phenomena were also observed for various types of peptides. The positive-ion signal of MALDI in detecting proteins or peptides was found to be greatly enhanced by the presence of a basic amino acid in their chains. The experimental results indicate that this enhancement may arise from proton transfer in solution by an acid-base reaction between the protein/peptide and matrix molecule. This pre-protonated mechanism provides a low energy barrier for the ionization of peptides in a MALDI process, and greatly reduces the energy threshold of MALDI. Matrix effects on the ionization mechanism are discussed.

Detection of delta F508 mutation of the cystic fibrosis gene by matrix-assisted laser desorption/ionization mass spectrometry

The most common mutation of the cystic fibrosis gene is characterized by the deletion of three nucleotides that code phenylalanine in the 508 position of the cystic fibrosis transmembrane conductance regulator. We report the first measurements by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry for the delta F508 mutation in cystic fibrosis carriers and patients. Furthermore, in a blind test, results from the normal and delta F508 mutant alleles in 30 clinical samples based on MALDI mass spectrometry and on conventional gel analysis of the DNA were in total agreement. These results demonstrate the utility of MALDI mass spectrometry in the molecular diagnosis of mutant alleles and point to its potential use for ultra-fast detection in large-scale screening of DNA mutations.

3-Aminopicolinic acid as a matrix for laser desorption mass spectrometry of biopolymers

3-Aminopicolinic acid (3-APA) was tested and found to be a useful matrix for matrix-assisted laser desorption/ionization of DNA and protein. Single-stranded DNA segments of 150-mer and double-stranded DNA of 246 base pairs were successfully detected by using 3-APA as an ultraviolet-absorbing matrix in a linear time-of-flight mass spectrometer. In the case of the double-stranded DNA, only parent ions corresponding to single-stranded DNA were observed. The comparison with 3-hydroxypicolinic acid and picolinic acid matrices is discussed.

Glucocorticoid activation of chromogranin A gene expression. Identification and characterization of a novel glucocorticoid response element

Glucocorticoids regulate catecholamine biosynthesis and storage at several sites. Chromogranin A, an abundant protein complexed with catecholamines in secretory vesicles of chromaffin cells and sympathetic axons, is also augmented by glucocorticoids. This study reports isolation of the rat chromogranin A promoter to elucidate transcriptional regulation of chromogranin A biosynthesis by glucocorticoids in neuroendocrine cells. Endogenous chromogranin A gene expression was activated up to 3.5-fold in chromaffin cells by glucocorticoid, in time-dependent fashion. Inhibition of new protein synthesis by cycloheximide did not alter the rise in chromogranin A mRNA, suggesting that glucocorticoids directly activate the chromogranin A promoter; nuclear runoff assays confirmed a 3.3-fold increased rate of initiation of new chromogranin A transcripts after glucocorticoid. Transfected rat chromogranin A promoter/luciferase reporter constructs were activated 2.6-3.1-fold by glucocorticoid, and selective agonist/antagonist studies determined that dexamethasone effects were mediated by glucocorticoid receptors. Both rat and mouse chromogranin A promoter/luciferase reporter constructs were activated by glucocorticoid. A series of promoter deletions narrowed the region of glucocorticoid action to a 93-bp section of the promoter, from position -526 to -619 bp upstream of the cap site. A 15-bp sequence ([-583 bp] 5'-ACATGAGTGTGTCCT-3' [-597 bp]) within this region showed partial homology to a glucocorticoid response element (GRE; half-site in italics) consensus sequence, and several lines of experimental evidence confirmed its function as a GRE: (a) site-directed mutation of this GRE prevented glucocorticoid activation of a chromogranin A promoter/reporter; (b) transfer of this GRE to a heterologous (thymidine kinase) promoter/reporter conferred activation by glucocorticoid, in copy number-dependent and orientation-independent fashion; and (c) electrophoretic gel mobility shifts demonstrated binding of this GRE by ligand-activated glucocorticoid receptor, though at 2.75-fold lower affinity than the glucocorticoid receptor interaction with a consensus GRE. The rat chromogranin A GRE showed functional and structural similarities to GREs in other genes proportionally regulated by glucocorticoids. We conclude that a discrete domain of the chromogranin A promoter is both necessary and sufficient to confer glucocorticoid regulation onto the gene, and that the activity of this region also explains the degree of activation of the endogenous gene by glucocorticoid.

The impact of health care financing on family budgets

Although businesses, federal and state governments, and insurance companies are major funding sources for health care, they are just intermediate sources. Ultimately, individuals and families pay all health care costs through out-of-pocket spending, insurance premiums, or federal, state, and local taxes. Using a microsimulation model with data from the 1987 National Medical Expenditure Survey, the Internal Revenue Service's Individual Tax Model, and the Consumer Expenditure Survey, the authors examine the distribution of health care spending, by decile, among families and individuals. They find that the distribution of health expenditures is very regressive, with low-income families paying twice the share of income paid by high-income families. The distribution of out-of-pocket expenditures, which comprise 24 percent of total spending, is the most regressive, with low-income families paying 8.5 times the share of income paid by high-income families. Spending on premiums is also regressive, and the regressivity would increase if everyone had private insurance. Expenditures through the public sector are progressive. Regressivity is greater among the elderly than the nonelderly. Out-of-pocket expenditures account for 41 percent of all health care spending by the elderly. A more equitably financed health care system would increase the share of funding raised through progressive taxes, and decrease reliance on expenditures made out of pocket and on premiums.

Hormone storage vesicle proteins. Transcriptional basis of the widespread neuroendocrine expression of chromogranin A, and evidence of its diverse biological actions, intracellular and extracellular

Chromogranin A (CgA) is an acidic soluble protein found in the core of secretory vesicles throughout the neuroendocrine system, from which it is coreleased by exocytosis with a variety of amine and peptide hormones and neurotransmitters. Much has now been learned about the structure of CgA, and there is emerging evidence that it plays several biological roles, both within secretory granules and after release from neuroendocrine cells. Factors governing its gene's widespread yet restricted (neuroendocrine) pattern of expression are only now being explored. In an attempt to understand how cells throughout the neuroendocrine system (but not exocrine or other nonendocrine cells) turn on and control the expression of CgA, we have isolated and begun to characterize functional 5' promoter elements from the rodent CgA genes. Within the sympathoadrenal system, interest focuses on a recently proposed (though as yet incompletely investigated) function of CgA: its ability to suppress catecholamine release from adrenal chromaffin cells when such cells are stimulated by their usual physiologic secretagogue. We anticipate that such studies will contribute to an understanding of this abundant, yet previously mysterious protein's role in neuroendocrine function.

Picolinic acid as a matrix for laser mass spectrometry of nucleic acids and proteins

We found that picolinic acid is a very good matrix for matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry of oligonucleotides, proteins and tRNA. Among the oligonucleotides, picolinic acid was shown to be effective for homo-oligonucleotides, d(G)40 and d(C)60, and for mixed-base oligonucleotides up to 190 bases. In the case of the single-stranded oligonucleotides, and of double-stranded ones as well, only parent ions corresponding to single-stranded DNA were observed. The efficiency for MALDI of oligonucleotides using the picolinic acid matrix was superior to that using 3-hydroxypicolinic acid. MALDI of transfer RNA phenylalanine-specific (tRNA(Phe)), a 76-base ribonucleic acid, was detected with a signal-to-noise ratio of > 10. By comparison with 3-hydroxypicolinic acid the results with picolinic acid are notably superior for all oligonucleotides.

Detection of 500-nucleotide DNA by laser desorption mass spectrometry

We report the first detection of DNA segments as large as 500 nucleotides by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, using picolinic acid and 3-hydroxypicolinic acid mixtures as desorption matrices. The successful detection of 500-nucleotide DNA indicates that laser mass spectrometry is now emerging as a new biotechnology tool for DNA-related research. It should be possible to utilize fast detection of large DNA segments by laser mass spectrometry for rapid human genome sequencing.

Neuroendocrine and reproductive consequences of overexpression of growth hormone in transgenic mice

Availability of recombinant growth hormone (GH) and development of long-acting formulations of this material will undoubtedly lead to widespread use of GH in animal industry and in medicine. GH can act, directly or indirectly, on multiple targets, but its influence on the reproductive system and on the hormonal control of reproduction is poorly understood. Overexpression of GH genes in transgenic animals provides a unique opportunity to study the effects of long-term GH excess. Transgenic mice overexpressing bovine, ovine, or rat GH (hormones with actions closely resembling, if not identical to, those of endogenous [mouse] GH), exhibit enhancement of growth, increased adult body size, and reduced life-span as well as a number of endocrine and reproductive abnormalities. Ectopic overexpression of bovine GH (bGH) driven by metallothionein or phosphoenolpyruvate carboxykinase promoters is associated with altered activity of hypothalamic neurons which produce somatostatin, loss of adenohypophyseal GH releasing hormone (GHRH) receptors, and suppression of endogenous (mouse) GH release. Elevation of plasma levels of GH (primarily bGH) and insulin-like growth factor (IGF-I) in these transgenic mice leads to increases in the number of hepatic GH and prolactin (PRL) receptors, in the serum levels of GH-binding protein (GHBP), in the percent of GHBP complexed with GH, and in the circulating insulin levels. In addition, plasma adrenocorticotropic hormone (ACTH) and corticosterone levels are elevated. Plasma levels of luteinizing hormone (LH), as well as its synthesis and release, are not consistently affected, but follicle-stimulating hormone (FSH) levels are suppressed, apparently due to pre- and post-translational effects. Pituitary lactotrophs exhibit characteristics of chronic enhancement of secretory activity, and plasma PRL levels are elevated. Prolactin responses to mating or to pharmacological blockade of dopamine synthesis are abnormal. Reproductive life span and efficiency are reduced in both sexes, with the severity and frequency of reproductive deficits being related to plasma bGH levels. Most transgenic females expressing high levels of bGH are sterile due to luteal failure. Overexpression of human GH which, in the mouse, interacts with both GH and PRL receptors leads to additional endocrine and reproductive abnormalities including stimulation of LH beta mRNA levels and LH secretion, loss of responsiveness to testosterone feedback, overstimulation of mammary glands, enhanced mammary tumorigenesis, and hypertrophy of accessory reproductive glands in males.

Adenovirus-mediated gene transfer for cystic fibrosis: quantitative evaluation of repeated in vivo vector administration to the lung

Adenoviral vectors have an important role as in vivo gene delivery vehicles in developing human gene therapy for the fatal pulmonary component of cystic fibrosis. In this study we evaluated the immune responses to wild-type adenovirus and replication-deficient, first generation adenoviral (Av1) vectors in the cotton rat (Sigmodon hispidus) and then quantitatively evaluated the efficiency of gene delivery and expression of single and repeated in vivo administration of Av1 vectors to the respiratory tract. Av1 vector reporter gene expression was quantitatively evaluated by employing a luciferase expression vector (Av1Luc1) and measuring luciferase activity in whole lung tissue homogenates by routine luminometry. Gene transfer and expression in naive animals (e.g. first Av1 vector dose) was efficient. A repeat dose also resulted in successful gene transfer and expression, although at a significantly reduced level (p < 0.01) compared with naive animals. This reduction inversely correlated with serum human adenovirus neutralizing antibody (HANA) titers. Importantly, increasing doses of Av1Cf2, an Av1 vector expressing the human CFTR cDNA, resulted in a graded HANA response consistent with a lack of in vivo replication. These observations have significant implications for repeated administration of adenoviral vectors to the lungs of individuals with cystic fibrosis.

Matrix-assisted laser desorption/ionization of restriction enzyme-digested DNA

Matrix-assisted laser desorption/ionization, by a time-of-flight mass spectrometer, has been successfully used for detection of restriction enzyme-digested DNA. However, the oligonucleotide segments detected correspond to the molecular weights of single strands.

Testosterone feedback on gonadotropin secretion and gene expression in transgenic mice expressing human growth hormone gene

To determine the effects of testosterone on the regulation of gonadotropins in metallothionein-1/human growth hormone (MT/hGH) transgenic mice, basal and gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release from incubated pituitaries, as well as pituitary content of LH, FSH, and mRNA for their respective beta subunits, were measured in normal and transgenic males that were injected with testosterone propionate (5 micrograms/g body weight; 24 hours before autopsy), injected with oil vehicle, castrated for 10 days, or sham operated. In normal (non-transgenic) males, exogenous testosterone induced the expected suppression, and castration induced the expected stimulation of various parameters of gonadotropin synthesis and release. In contrast, in testosterone-treated and in castrated MT/hGH transgenic mice the release of LH and the pituitary levels of LH-beta mRNA did not differ from the corresponding values measured in vehicle-injected and sham-operated transgenic controls. Pituitary LH content was elevated in testosterone-treated MT/hGH transgenic mice but was not changed in castrated transgenic males. The changes in pituitary levels of FSH and FSH-beta mRNA and in FSH release in MT/hGH transgenic mice in response to testosterone and castration were different from the changes in LH and LH-beta mRNA in the same mice, but similar to the changes of FSH and FSH-beta message produced in normal mice by identical treatments. We suggest that hGH expression attenuates the effects of testosterone on the mechanisms controlling LH release, with less influence on testosterone regulation of LH synthesis. These effects of hGH expression appear to be selective for LH, without influencing the FSH control system.

Matrix-assisted laser desorption ionization of oligonucleotides with various matrices

Ferulic acid, 3-hydroxypicolinic acid (3-HPA), and 2,5-dihydroxybenzoic acid (2,5-DHB) were used as matrices in MALDI of various oligonucleotides. It was found that 2,5-DHB is an excellent matrix for polydeoxyribothymidylic acid. A poly-T oligonucleotide with a size of 130 bases was successfully detected. 3-HPA was found to be a good matrix for MALDI of homo-oligomeric deoxynucleotides as well as those containing four different bases. Parent ions of pd(A)60, d(T)100, d(G)40, and d(C)40 were observed, and a mixed-base oligonucleotide of 150-mer was also detected. Polymer ions of poly-A as large as 420-mer were measured; however, the efficiency for detecting poly-T with 3-HPA as a matrix was slightly worse than when 2,5-DHB was used. Comparisons of three matrices for various oligonucleotides is also presented.

Brefeldin-A inhibits the delivery of the polymeric immunoglobulin receptor to the basolateral surface of MDCK cells

We have studied the effects of brefeldin A (BFA) on the polarized delivery of the polymeric immunoglobulin receptor to the basolateral surface of MDCK cells. Unlike the delivery of several other basolateral membrane and secretory proteins, the delivery of the polymeric immunoglobulin receptor from the trans-Golgi network to the cell surface was inhibited by BFA. The effect of BFA treatment was apparent at 1.0 microgram/ml (36% inhibition), and maximal inhibition was observed at 10 micrograms/ml (70% inhibition). The delivery of the receptor from the endoplasmic reticulum to the basolateral surface was even more sensitive to the effect of BFA; delivery was inhibited 95% in cells treated with 1 micrograms/ml BFA. The selective action of BFA on the basolateral delivery of the polymeric immunoglobulin receptor suggests that there may be multiple pathways for delivery of proteins to the basolateral cell surface of MDCK cells.

Development of synthetic Brassica amphidiploids by reciprocal hybridization and comparison to natural amphidiploids

In a previous study we proposed that cytoplasmic genomes have played an important role in the evolution of Brassica amphidiploid species. Based on this and other studies, we hypothesized that interactions between the maternal cytoplasmic genomes and the paternal nuclear genome may cause alterations in genome structure and/or gene expression of a newly synthesized amphidiploid, which may play an important role in the evolution of natural amphidiploid species. To test this hypothesis, a series of synthetic amphidiploids, including all three analogs of the natural amphidiploids B. napus, B. juncea, and B. Carinata and their reciprocal forms, were developed. These synthetic amphidiploids were characterized for morphological traits, chromosome number, and RFLPs revealed by chloroplast, mitochondrial, and nuclear DNA clones. The maternal transmission of chloroplast and mitochondrial genomes was observed in all of the F1 hybrids examined except one hybrid plant derived from the B. rapa x B. oleracea combination, which showed a biparental transmission of organelles. However, the paternal chloroplast and mitochondrial genomes were not observed in the F2 progeny. Nuclear genomes of synthetic amphidiploids had combined RFLP patterns of their parental species for all of the nuclear DNA clones examined. A variation in fertility was observed among self-pollinated progenies of single amphidiploids that had completely homozygous genome constitutions. Comparisons between natural and synthetic amphidiploids based on restriction fragment length polymorphism (RFLP) patterns indicated that natural amphidiploids are considerably more distant from the progenitor diploid species than the synthetic amphidiploids. The utility of these synthetic amphidiploids for investigating the evolution of amphidiploidy is discussed.

Gonadotropin secretion, synthesis, and gene expression in two types of bovine growth hormone transgenic mice

Expression of the mouse metallothionein-I (MT) promoter/bovine growth hormone (bGH) or the phosphoenolpyruvate carboxykinase (Pepck) promoter/bGH fusion genes in male transgenic mice is associated with alternations in adenohypophyseal function and fertility. To determine the effects of these gene constructs on gonadotropin synthesis and secretion, we have examined basal and GnRH-stimulated LH and FSH release in vitro using static incubations and perifusions of the pituitary; we have also examined pituitary content of LH, FSH, LH beta mRNA, and FSH beta mRNA in MT/bGH and Pepck/bGH transgenic mice as well as in normal mice. In addition, we have measured LH and FSH release from normal pituitaries transplanted under the kidney capsules of Pepck/bGH transgenic or normal mice. We found that in Pepck/bGH transgenic mice, pituitary contents of FSH and FSH beta mRNA were reduced, while FSH release in vitro in pituitary incubations and perifusions was increased. Steady-state levels of LH beta mRNA as well as LH responses to GnRH in perifusions were reduced; LH release in incubations and pituitary LH content were not changed; and basal LH secretion in perifusions was increased. In MT/bGH transgenic mice, in which peripheral bGH levels are much lower than in Pepck/bGH mice, similar trends were observed, but most of the apparent differences between transgenic and normal animals were not statistically significant. When normal pituitaries were transplanted under the kidney capsules of Pepck/bGH transgenic mice, the expected decrease in LH and FSH secretion was attenuated and the response to GnRH stimulation was lost.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser mass spectrometry of oligonucleotides with isomer matrices

Various isomer matrices were used for laser-desorption ionization of mixtures of oligomers. It was found that the efficiency of production of oligomer ions changed drastically when different isomers were used as matrices. For selected matrix materials, parent oligomer ions with sizes up to 64 bases were observed.

Gonadotropin secretion, synthesis, and gene expression in human growth hormone transgenic mice and in Ames dwarf mice

The expression of the mouse metallothionein-I (MT) promoter/human GH (hGH) fusion gene leads to reduced fertility and increased plasma LH levels in male MT/hGH transgenic mice. To determine the effects of hGH on gonadotropin synthesis and release, we have examined basal and GnRH stimulated LH and FSH release in pituitary incubations and perifusions; and pituitary content of LH, FSH, LH-beta messenger RNA (mRNA), and FSH-beta mRNA in MT/hGH transgenic males and in their normal littermates. For comparison, similar studies were performed in GH and PRL deficient Ames dwarf mice in which plasma gonadotropin levels are known to be reduced. We have also measured the LH and FSH release from normal pituitaries transplanted under the kidney capsule of MT/hGH transgenic or normal mice. We found that in MT/hGH transgenic mice, there were parallel increases in unstimulated and GnRH stimulated LH release from pituitary incubation, in pituitary LH content and in LH-beta mRNA levels. In pituitary perifusion, the basal LH secretion was elevated, whereas LH responses to GnRH pulses were not altered. In transgenic males, FSH-beta mRNA was increased, whereas basal and GnRH-stimulated FSH release and pituitary FSH content did not differ from their normal controls. After normal pituitaries were transplanted to kidney capsules of MT/hGH transgenic mice, the expected decrease in LH and FSH secretion was attenuated and the responsiveness to GnRH stimulation was maintained. In Ames dwarf mice, all gonadotropin content and release, as well as pituitary beta-mRNA contents were decreased. We conclude that in MT/hGH transgenic mice, the expression of LH-beta and FSH-beta gene is increased. In addition, there is a translational or posttranslational inhibitory influence on FSH synthesis. Although our previous studies suggest that the effects of hGH gene expression on LH and FSH release are exerted primarily at the hypothalamic level, the present results suggest existence of GnRH unrelated peripheral factors which can directly stimulate pituitary gonadotropin synthesis and release. In Ames dwarf mice, the deficiency of GH and PRL, as well as TSH, is associated with decreased LH-beta and FSH-beta gene expression which may account for the reduction in plasma gonadotropin levels.

DIDS inhibition of deformation-induced cation flux in human erythrocytes

The permeability of human erythrocytes to sodium, potassium and calcium increases when the cells are deformed by shear. We now report that the anion-exchange inhibitor DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid) inhibited 55-60% of the deformation-induced flux with an apparent K1/2 of 1 microM. Covalently bound DIDS was also effective. In cells partially derivatized at 0 degrees C (pH 7.4), anion exchange and the deformation flux were inhibited in parallel, implying that lysine a is the site of inhibition for both fluxes. Ektacytometry showed that DIDS does not inhibit by lowering the cell's ability to deform. Crosslinking of lysines in Band 3 was not required for inhibition of the stress flux, as demonstrated by electrophoretic analysis of chymotrypsin-cleaved Band 3 after DIDS treatment. Chymotrypsin cleavage itself did not affect the cation flux rates. DNDS, an anion exchange inhibitor that binds to the chloride site on Band 3 but is unable to derivatize lysine a, is an ineffective inhibitor of the deformation flux. Other high-affinity inhibitors of anion exchange were also relatively ineffective against the deformation flux, and anion exchange itself was unchanged by shear. These results suggest that 55-60% of the deformation-induced cation movement traverses a route that includes Band 3, but is distinct from the pathway utilized by anion exchange. Chloride-dependent cation pathways do not participate in the stress induced cation flux, since complete exchange of intracellular chloride for sulfate had no effect on the rates. Deformation of erythrocytes by laminar shear appears to increase the non-specific cation permeability.

Induction of a Ca(2+)-activated K+ channel in human erythrocytes by mechanical stress

Mechanical deformation of normal ATP-replete human erythrocytes increased their permeability to Ca2+ sufficiently to turn on the Ca(2+)-activated K+ channel (the Gardos channel). When Ca2+ is absent, mechanical deformation of normal erythrocytes induces an equivalent increase the permeability of both Na+ and K+, In the presence of 0.1 to 1 mM Ca2+, a further increase in the K+ efflux rate was seen. There was no increase in Na+ flux above that induced by deformation itself. The involvement of the Ca(2+)-activated H channel was verified by showing the specific inhibitors of the channel, quinine and charybdotoxin, prevent the Ca(2+)-induced increase in K+ efflux. These results are consistent with a model of sickle cell dehydration proposed by Bookchin et al. ((1987) Prog. Clin. Biol. Res. 240, 193-200). The estimated rate of Ca2+ entry under these conditions (37 degrees C, 1000 dyne/cm2, and laminar shear) was about 1 mmol/loc per h.

[Observation of efficacy of different dialytic therapies in renal transplantation preparation]

Fifty-seven cadaveric renal transplantations in fifty-five cases were analysed of them, thirty cases were prepared by continuous ambulatory peritoneal dialysis (CAPD group); twenty-seven transplantations in twenty-five cases were prepared by hemodialysis (HD group). Our data show that there is no significant difference in the survival duration between CAPD group and HD group; that there is also no significant difference in the survival duration between the two groups treated with the same immunosuppressive drugs, and that patients prepared by CAPD have a low risk of peritonitis after transplantation. It is better not to remove the Tenckhoff catheter until the graft function is stable so that it can be used for the transient peritoneal dialysis in the case of the insult of graft function or for the sampling of the peritoneal effusion for diagnosis of suspectable peritonitis after renal transplantation.

The prediction of anatomical morphology of primary aldosteronism using serum 18-hydroxycorticosterone levels

Serum 18-hydroxycorticosterone, aldosterone, and potassium were measured under basal conditions in 34 patients with documented primary aldosteronism, 10 patients with essential hypertension, and 9 normal subjects. The results revealed that 22 of 23 patients with aldosterone-producing adenomas had 18-hydroxycorticosterone levels greater than 100 ng/dl, and all 9 patients with idiopathic adrenal hyperplasia had plasma levels less than 100 ng/dl. Two patients with unusual macromicronodular hyperplasia of the adrenal glands had levels greater than 100 ng/dl. We found a significant relationship between serum potassium and the ratio of 18-hydroxycorticosterone to aldosterone in patients with idiopathic adrenal hyperplasia, but not in those with an aldosterone-producing adenoma. We conclude that measurement of serum 18-hydroxycorticosterone is a useful predictor of the etiology of primary aldosteronism.

Heterogeneity in induced heat resistance and its relation to synthesis of stress proteins in rat tumor cell clones

Tumor cell clones isolated from a rat 13762NF mammary adenocarcinoma and its spontaneous metastases were heterogeneous in their survival responses to continuous 42 degrees heating. Clones MTLn3 and MTF7 had similar initial survival responses; they were significantly less sensitive than clone MTC. Following the first decrease in survival, different magnitudes of induced thermal resistance were observed. When ratios of the first and resistant slopes of survival curves were compared (the thermotolerance ratio), the order of induced thermal resistance was MTLn3 greater than MTF7 greater than MTC. These clones were compared for the rates of synthesis of heat stress proteins (HSP). The same four major HSP at Mr 112,000, 90,000, 70,000, and 22,000 were induced or enhanced in all 3 clones. The rates of synthesis of these HSP were analyzed through a unique system of computer-assisted video densitometry and digitization. When all 4 HSP were analyzed as a group, the rates were significantly different (p less than 0.017), and the rank order of rates of synthesis was significant with MTLn3 greater than MTF7 greater than MTC. Induction kinetics of the individual HSP were different. Individually, the HSP at Mr 112,000, 90,000, and 22,000 were synthesized at significantly different rates between clones (p less than 0.001) but the Mr 70,000 HSP was not. Absolute total protein synthesis was highest for clone MTLn3, and MTF7 was higher than MTC but only marginally. Although absolute accumulations of these HSP could not be directly compared between these clones, the higher rates of HSP synthesis in these tumor cell clones correlated with more thermal resistance. These data support the working hypothesis that one or more of these HSP have a direct role in the mechanism(s) for inducing thermal resistance in rat tumor cells, but other factors such as total protein synthesis could modify the complex bio-chemical and phenotypic pathways involved in induced HSP and thermal resistance.

Relation between glucose, insulin, and growth hormone in the fetus during labor and at delivery

Maternal, fetal and umbilical blood glucose, insulin, and human growth hormone (HGH) levels were measured to determine their relation during labor and at delivery. There was a positive correlation between fetal glucose and HGH, as well as between the fetal insulin and HGH values. Higher birthweights were associated with lower umbilical venous HGH and higher insulin levels. Thus, the balance between insulin and growth hormone might be involved in the regulation of fetal growth.