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H Hermann

Publications and source records attributed to H Hermann.

At least 19 recordsLinked to original sources
PubMed1992

pYLZ vectors: Saccharomyces cerevisiae/Escherichia coli shuttle plasmids to analyze yeast promoters.

Two yeast/Escherichia coli shuttle vectors have been constructed to analyze promoter structures in Saccharomyces cerevisiae: the multicopy vector, pYLZ-2, and the centromere-based vector, pYLZ-6. Both plasmids contain the coding region of lacZ from E. coli lacking the N-terminal eight amino acids. The truncated reporter gene is preceded by a short polylinker (MCS) suitable for the insertion of promoter fragments. The vectors allow for the study of expression from complete promoters containing UAS and TATA elements, transcriptional start point(s) and the original context of the ATG start codon of a yeast gene. A yeast terminator fragment has been inserted 3' of the lacZ coding region. It contains the transcription termination region of the convergently transcribed yeast genes, GCY1 and PFY1, together with sequences corresponding to the mapped 3'-ends of the respective mRNAs. As an example, reporter activity was measured with promoter fragments from three yeast genes (GCY1, PFY1 and LEO1). The results demonstrate the efficiency of the plasmids for studying constitutive and regulated transcription, both at high and low levels of expression.

Base Sequence↗
PubMed1992

Expression of yeast cytochrome c1 is controlled at the transcriptional level by glucose, oxygen and haem.

The nuclear gene for cytochrome c1 in Saccharomyces cerevisiae (CYT1) was localized on chromosome XV. Its upstream region was identified by functional complementation. Fusion to the lacZ reporter gene on a CEN plasmid allowed study of the effect of carbon sources and of specific deletion mutations on expression of the gene in yeast transformants. Detailed promoter analysis combined with expression studies in recipient strains defective in regulatory genes identified cis-acting sites and transcription factors involved in the regulated expression of the cytochrome c1 gene. These analyses showed that, in the presence of glucose, transcription of CYT1 is positively controlled by oxygen, presumably through the haem signal, and mediated by the HAP1-encoded transactivator. It is additionally regulated by the HAP2/3/4 complex which mediates gene activation mainly under glucose-free conditions. Basal transcription is, in part, effected by CPF1, a centromere and promoter-binding factor.

Base Sequence↗
PubMed1989

Metallothionein-vasopressin fusion gene expression in transgenic mice. Nephrogenic diabetes insipidus and brain transcripts localized to magnocellular neurons.

Arginine vasopressin (AVP) is a potent neuroactive and vasoactive nonapeptide encoded in and processed from a precursor, preproarginine vasopressin-neuro-physin II (preproAVP-NPII). To study the physiologic consequences of a genetic model of chronic hypervasopressinemia transgenic mice were produced by introduction of a mouse metallothionein-rat-ppAVP-NPII fusion gene into the germ line of mice. Three stable transgenic pedigrees were analyzed through several generations. Levels of immunoreactive AVP and neurophysin (NP) in sera, livers, kidneys, intestines, pancreas, and brains were markedly elevated. Chromatographic analyses showed sera levels of approximately 500 pg/ml (normal 0-20 pg/ml) of authentic AVP non-apeptide and serum osmolalities were elevated, 315.4 +/- 1.4 mosm/liter (control, 307.3 +/- 1.1), consistent with a state of mild nephrogenic diabetes insipidus. Brain levels of immunoreactive AVP in transgenic mice were 3-4-fold elevated 145 +/- 15 ng/g versus 31 +/- 7 (controls). Although immunoreactive AVP in livers and intestines, and to some extent kidneys, consisted predominantly of unprocessed precursors, in brain and pancreas greater than 90% of AVP consisted of processed bioactive nonapeptide, as determined by chromatography and measurements of cAMP-generation in LLC-PK1 cells. Immunocytochemistry localized immunoreactive AVP to the exocrine pancreas and to the magnacellular neurons (SON and PVN) of the hypothalamus. Expression of the fusion gene in the hypothalamus was further demonstrated by Northern analyses of fusion gene specific transcripts and in situ histohybridization. Although the fusion gene contained only 35 base pairs of 5'-flanking DNA of the ppAVP-NPII gene, a tentative neuronal cell-specific expression element, -17GCCCAG-CC-10 resides in this sequence and may confer neuron-specific expression to the fusion gene.

Animals↗
PubMed1988

Isolation and partial characterization of dermatan sulfate proteoglycans from human post-burn scar tissues.

Dermatan sulfate (DS) proteoglycans (PGs) were extracted from human post-burn scar (Sc) tissues with 4M guanidinium chloride and isolated from the extracts by DEAE-cellulose chromatography and by differential ethanol precipitation. The DS.PGs were further purified by Sepharose CL-6B column chromatography. The average molecular weight (Mr) of hypertrophic scar (HSc) tissue DS.PGs was 39,000 based on sedimentation equilibrium measurements. Alkaline borohydride treatment of DS.PGs liberated glycosaminoglycan (GAG) chains and the presence of xylitol indicated that these chains were attached to protein core by xylosyl residues. The average Mr of the DS.GAG chain from HSc and normal scar (NSc) samples were 23,500 and 20,000 respectively. After digestion of the HSc and NSc, DS.PGs with chondroitinase ABC in the presence of proteinase inhibitors, two peptide components with Mr values of 21,500 and 17,000 were detected by SDS-polyacrylamide gel electrophoresis using reducing conditions. Analysis of the protein core fractions derived from NSc and HSc DS.PGs by Sepharose CL-6B column chromatography showed the presence of a single NH2-terminal amino acid (aspartic acid) and also that the fractions with different KAV values had an identical NH2-terminal sequence (A1-A5). The A1-A23 sequence of NSc DS.PG (major fraction, C): NH2Asp-Glu-Ala-O-Gly-Ile-Gly-Pro-Glu-Val-Pro-Asp-Asp-Arg-Asp-Phe-G lu-Pro- Ser-Leu-Gly-Pro-Val was the same as reported for a DS.PG isolated from human fetal membrane (HFM) tissue (Brennan et al., 1984). ELISA inhibition assay using monoclonal antibodies raised in rabbit against the NH2-terminal peptide (containing 15 amino acids) of human fetal membrane tissue were found to cross-react with HSc and NSc DS.PGs. Monoclonal antibodies to bovine skin DS.PGs protein core (Pearson et al., 1983) did not show any cross-reactivity with scar DS.PGs. These results show that the scar DS.PGs described here are different from normal bovine skin DS.PGs in the size and type of the protein core, and that in all the samples, the peptide components have the same NH2-terminal amino acid sequence.

Amino Acids↗
PubMed1988

Sodium butyrate increases glucagon and insulin gene expression by recruiting immunocytochemically negative cells to produce hormone.

Current evidence suggests that a multipotential endodermal progenitor cell may give rise to all islet cell phenotypes. We characterized two hormone-producing rat islet (RIN) cell lines derived from a radiation-induced islet tumor by immunocytochemistry, Northern blot analysis, and radioimmunoassay of secreted hormone. Using antisera to glucagon, insulin, and somatostatin, we found that less than 15% of the cells in any of these three islet cell lines contained immunopositive cells. The number of cells staining for the hormone correlated with mRNA levels and immunoreactive secreted hormones. Sodium butyrate, a short-chain aliphatic fatty acid, slowed cell growth and increased dramatically the percentage of cells staining for glucagon and insulin. The increase in immunopositive cells was accompanied by an increase in glucagon and insulin mRNAs and secreted glucagon and insulin. These observations indicate that sodium butyrate increases glucagon and insulin gene expression by recruiting previously immunonegative cells to produce hormone. The relationship of DNA synthesis and hormone production was assessed by pulse-labeling RIN cells with [3H]thymidine, which was followed by autoradiography and immunocytochemistry. [3H]thymidine incorporation was observed in a lower percentage of immunopositive compared with immunonegative cells. Furthermore, sodium butyrate reduced the number of [3H]thymidine-labeled cells and increased the number of immunopositive cells. These observations suggest that sodium butyrate differentiates the islet cells and thereby increases the expression of the glucagon and insulin genes.

Adenoma, Islet Cell↗
PubMed1987

Nifedipine monotherapy in the hypertensive elderly: a placebo-controlled clinical trial.

A single-blind, placebo-controlled study was carried out to evaluate the suitability of slow-release nifedipine as antihypertensive monotherapy for the elderly. After a wash-out period, nifedipine slow-release tablets (20 mg twice daily) followed by matching placebo were administered, each for 4 weeks, to 23 patients over 60 years of age with essential mild to moderate hypertension. Nifedipine significantly reduced the systolic and diastolic blood pressure, and increased the pulse rate in both supine and upright positions. The pre-treatment supine systolic blood pressure proved the best single predictor of the blood pressure decreases in both positions. The decrease in mean arterial blood pressure correlated significantly with the nifedipine plasma concentration. Significant biochemical changes were observed with nifedipine, namely increased serum K+ level and decreased levels of serum Na+, cholesterol and triglycerides. Side-effects in general were mild and transient; nevertheless, 3 patients dropped out because of severe leg oedema.

Aged↗
PubMed1985

Studies on human scar tissue proteoglycans.

The proteoglycans (PGs) in pooled normal scars and pooled hypertrophic scars were extracted with 4 M guanidinium chloride and isolated by DEAE-cellulose chromatography. The PG samples were then fractionated further by dissociative CsCl density gradient sedimentation. Following cleavage of the density gradient PG fractions with alkaline NaB3H4, the glycosaminoglycan (GAG) constituents were isolated and analyzed by quantitative cellulose acetate electrophoresis. In addition, single samples of normal skin and a keloid scar were also analyzed. The results showed that the hypertrophic scars had a higher average content of extractable and also residual PGs than did the normal scars but a wide range of values was obtained for each type of scar. Some differences were noted in the amounts and distribution of the GAGs in CsCl gradient fractions, in the different types of scar tissue. The PGs in tissues were distributed in low-, medium-, and high density fractions and are, therefore, heterogeneous. Dermatan sulfate (DS) was the major GAG in each tissue and smaller quantities of chondroitin sulfate (CS), heparan sulfate (HS), and heparin (HP) were also present. In addition, 2 other GAG constituents were also detected. Based on the susceptibility of these GAGs to enzymes and nitrous acid treatments, one was a HS or HP while the second was a DS. The major differences in the PG composition of the scar tissues were the higher proportions of low-density CS-PGs in the keloid scar and of low density DS-PGs in hypertrophic and keloid scars.

Chromatography, DEAE-Cellulose↗
PubMed1983

Differentiation of influenza A virus nucleoproteins in enzyme-linked immunosorbent assay.

The serum antibody titre to the nucleoprotein (NP) of the influenza virus recombinant MRC-11 was determined in virus strains A/USSA/5/80 (H3N2), A/Hong Kong/8/64 (H3N2), A/duck/Ukraine/63 (Hav7Neq2) and in a recombinant strain between A/tern/Frunse/334/78(Hav4Nav1) and A/PR/8/34(H0N1) using the enzyme-linked immunosorbent assay (ELISA). Significant differences between the NP of these strains were found proving the usefulness for ELISA for such investigations.

Antigens, Viral↗
PubMed1979

Systemic absorption and sustained effects of vaginal estrogen creams.

Systemic absorption and sustained effects of two estrogen vaginal cream preparations (Premarin and Estrace) were measured in 29 postmenopausal women receiving daily applications. With both preparations, vaginal absorption of estrogens into the systemic circulation was rapid, efficient, and sustained. It is apparent that estrogen vaginal cream preparations, as widely used in clinical practice for their local effects on the vaginal mucosa, actually result in sustained high estrogen levels in the systemic circulation. The vaginal route shows promise when systemic estrogen therapy is indicated, but is dangerous when estrogen is contraindicated.

Absorption↗
PubMed1976

Congenital absence of the left pericardium: an unusual palpation finding and echocardiographic demonstration of the defect.

A patient with classical clinical and roentgenographic features of congenital absence of the left pericardium is described. On physical examination in the supine position, the precordial apical impluse was markedly displaced laterally. In the left lateral decubitus position, however, the apical impulse was felt in a mor medial location. This apparently paradoxical movement of the apical impulse was not found in persons with normal hearts or with left ventricular enlargement of hypertrophy, and may be characteristic of the pericardial defect. Further, with echocardiography we were able to demonstrate the absence of a pericardial echo on the lateral surface of the heart. Thus, echocardiography may be a useful noninvasive tool in the diagnosis of this defect.

Adult↗