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Biomedical subjects

S Aho

Publications and source records attributed to S Aho.

At least 55 records · Page 3Linked to original sources
PubMed1995

Systemic effects of epidural dexamethasone injections.

OBJECTIVES: to evaluate potential systemic effects of a single epidural injection of dexamethasone. PATIENTS AND METHODS: each of nine patients (five males and four females, mean age 47 +/- 11.8 years) admitted for sciatica was given a single epidural injection of 15 mg dexamethasone acetate. Before the injection (D0) and two (D2), seven (D7) and 21 (D21) days after the injection, the following laboratory tests were performed: serum cortisol and ACTH in the morning after an overnight fast, free cortisol in a 24-hour urine collection, fasting serum levels of glucose, triglycerides and cholesterol, serum levels of sodium and potassium. Blood pressure was measured on D0, D2, and D7. RESULTS: Serum cortisol, ACTH and urinary cortisol were profoundly decreased on D2 and D7 but normal on D21. There were no changes in fasting serum glucose, triglycerides, cholesterol, sodium or potassium levels. CONCLUSION: a single epidural injection of 15 mg dexamethasone acetate is associated with transient adrenal suppression, denoting passage of the steroid into the systemic bloodstream. However, evidence of hypercorticism is usually lacking.

Adrenocorticotropic Hormone↗
PubMed1994

Characterization of MEL genes in the genus Zygosaccharomyces.

We cloned and sequenced a Zygosaccharomyces cidri MEL gene with a view to investigating the structure and regulation of yeast MEL genes. The amino acid sequence deduced from the nucleotide sequence showed 78.6% and 78.2% similarity to Saccharomyces cerevisiae and Saccharomyces pastorianus alpha-galactosidases, respectively. The expression of the MEL gene in several Zygosaccharomyces strains was induced by galactose. An electrophoretic karyotype of several Zygosaccharomyces species was obtained using contour-clamped electric field gel electrophoresis. The minimum number of chromosomes was five for Z. cidri, six for Z. fermentati, three for Z. florentinus, and four for Z. microellipsoides. The sizes of the chromosomes were generally larger than those of S. cerevisiae, the smallest containing approximately 0.4 megabase. The MEL gene was located, using the Z. cidri MEL gene as a probe, on the largest chromosome of the Z. cidri strains. In addition, a smaller chromosome (600 kb) in Z. cidri strain CBS4575 showed hybridization to the homologous MEL probe. This chromosome was absent in Z. cidri strain CBS5666. The probe hybridized to the largest chromosome of Mel+ Z. fermentati strains but failed to hybridize to any chromosome of Mel+ Z. mrakii or Z. florentinus strains. These results suggest the existence of a polymorphic MEL gene family in the yeast Zygosaccharomyces.

Amino Acid Sequence↗
PubMed1993

Characterization of an intronless collagen gene family in the marine sponge Microciona prolifera.

Two independent clones from the genomic DNA of a marine sponge Microciona prolifera were isolated by hybridization to the Caenorhabditis elegans Col-1 gene and one clone was obtained from genomic DNA by PCR. They contain open reading frames (MpCol1, MpCol2, MpCol3, MpCol4) capable of coding for a family of collagens different from those previously found in sponges. Southern blotting of genomic DNA suggested the presence of several other homologous genes. cDNA clones covering most of the triple-helical coding domain and the 3' untranslated region of MpCol1 were isolated by specific primers and reverse PCR. Two cDNA clones end in the middle of an AATAAA sequence 170 bp downstream from the translation stop codon of MpCol1. The putative NH2-terminal noncollagenous peptide is composed of only seven amino acid residues. The 1074-bp triple-helical coding region is not interrupted by intervening sequences. It codes for a polypeptide of 120 Gly-Xaa-Yaa triplets with only one short interruption near the COOH terminus. A putative N-glycosylation sequence (Asn-Gly-Ser), three Arg-Gly-Asp triplets known as cell recognition peptides, frequent Lys residues in the Yaa position (which are templates for hydroxylation), several Lys-Gly-Asn/Xaa-Arg peptides known as the lysyl oxidase recognition site, and long stretches without imino acids could be found within the triple-helical domain. The short COOH-terminal noncollagenous domain closely resembles that of nematode cuticular collagens and vertebrate nonfibrillar collagens. Our results strongly support the idea that the diversity of collagen genes and gene families found in higher organisms already existed in sponge.

Amino Acid Sequence↗
PubMed1993

MEL gene polymorphism in the genus Saccharomyces.

In Saccharomyces spp. the ability to use melibiose depends on the presence of a MEL gene encoding alpha-galactosidase. We used two cloned MEL genes as probes to characterize the physical structure and chromosomal location of the MEL genes in several industrial and natural Mel+ strains of Saccharomyces cerevisiae, Saccharomyces pastorianus, and Saccharomyces bayanus. Electrokaryotyping showed that all of the S. pastorianus strains and most of the S. bayanus strains studied had one MEL locus. The MEL gene in S. bayanus strains was similar but not identical to the S. pastorianus MEL gene. Mel+ S. cerevisiae strains had one to seven loci containing MEL sequences. The MEL genes of these strains could be divided into two categories on the basis of hybridization to MEL1, one group exhibiting strong hybridization to MEL1 and the other group exhibiting weak hybridization to MEL1. In S. pastorianus and S. bayanus strains, the MEL gene was expressed as a single 1.5-kb transcript, and the expression was galactose inducible. In some S. cerevisiae strains, the MEL genes were expressed even without induction at fairly high levels. Expression was usually further induced by galactose. In two strains, CBS 5378 and CBS 4903, expression of the MEL genes was at the same level without induction as it was in most other strains with induction. In all S. cerevisiae strains, irrespective of the number of MEL genes, mRNA of only one size (1.6 kb) was observed.

Chromosome Mapping↗
PubMed1993

[Bone metastasis of hepatocellular carcinoma. Apropos of 22 cases].

There have been few studies and case-reports of bone metastases from hepatocellular carcinoma. To determine the characteristics of these metastases, we retrospectively studied 22 patients in whom the diagnosis was established either on the basis of concomitant occurrence of malignant bone lesions and hepatocellular carcinoma in the absence of other detectable malignant disease (n = 15) or on the basis of histological evidence of bone metastasis from an hepatocellular carcinoma (n = 7). There were 21 males and one female. Mean age was 62.5 years. Most patients (88.2%) had chronic alcohol abuse. The bone metastases occurred as the first manifestation of the liver cancer in half the cases (11/22). Time interval between onset of bone symptoms and admission was less than one month in 6 of 11 patients; mean interval was 7.4 weeks. Hepatomegaly was found upon initial physical evaluation in 9 of 11 patients. Pain was the main symptom of bone disease (18/22). Palpable bone masses were found in 6 of 22 patients. Purely osteolytic lesions were seen on roentgenograms in every case; rupture of the cortex and spread to adjacent soft tissues were common findings. The radionuclide bone scan was normal in four of 12 patients. An advanced primary hepatic tumor was found in 84.2% of cases. Histologic examination of bone specimens established the diagnosis of metastasis from a hepatocellular carcinoma in 7 of 9 patients (77.8%). Severe bleeding occurred during one of the nine biopsy procedures. Patients were given symptomatic treatment. Systemic chemotherapy was used in five patients, unsuccessfully. Median survival was three months.

Bone Neoplasms↗
PubMed1993

[Management of the thyroid nodule. Preliminary results of a practice survey of 685 general practitioners and specialists].

The authors present the preliminary results of a mailed survey of policies for the management of thyroid nodules (TN). This survey involved 685 general practitioners and specialists and was carried out at the initiative of APNET (National Educational Association for Training in Therapeutics) with the aid of ANDEM (National Agency for the Development of Medical Evaluation). Twelve percent of responders (13.1% among GPs) declare that they do not manage TNs. Those have been excluded from the analysis. The answers taken into account come from general practitioners (n = 179), endocrinologists (n = 233), specialist surgeons (n = 64), ENT practitioners (n = 93) and nuclear medicine practitioners (n = 26). The average number of patients with TN seen in a year varies according to the specialty: 6 a year for GPs, 30 in ENT, 89 for endocrinologists, 105 for surgeons. This survey reveals a number of common position: 1) the therapeutic attitude must be customized according to clinical findings and to complementary tests; 2) prescriptions are homogeneous as regards radionuclide scanning (technetium or iodine), TSH assays, ultrasonography and T4 assays; 3) ultrasonography is used in first intention; 4) ultrasonography has limitations, and is regarded by a majority or responders as unable to provide information about benignancy or malignancy. Conversely, responses are much more variable about a number of points: 1) the use of fine needle aspiration cytology which is mainly used by endocrinologists and nuclear medicine practitioners; 2) the management of nodules discovered on ultrasonography: the attitude is different from that adopted with palpable nodules for endocrinologists, surgeons and nuclear medicine practitioners, and identical for most general and ENT practitioners; 3) the usefulness of a suppressing treatment with thyroid hormones. Both general practitioners (47%) and, even more so, specialists (84%) are aware of these differences in practices. Faced to this situation, 69% of specialists are in favor of establishing consistent practices, but a minority (42%) only think that it is possible. Thus recommendations about practices may be useful only if they are adapted to the type of practice and to the conditions of access to complementary tests, and they should be aimed at rationalizing management rather than making it consistent.

Endocrinology↗
PubMed1992

Production of cyclomaltodextrin glucanotransferase of Bacillus circulans var. alkalophilus ATCC21783 in B. subtilis.

The cyclomaltodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) gene from an alkalophilic Bacillus circulans var. alkalophilus ATCC21783 was cloned into Escherichia coli and B. subtilis. When cloned from E. coli to B. subtilis, the entire insert containing the CGTase gene was, depending on the plasmid construction, either unstable or the recombinant B. subtilis did not secrete the enzyme in significant amounts. To achieve efficient enzyme production in B. subtilis, the gene was placed under the control of the B. amyloliquefaciens alpha-amylase promoter. In one of the constructions, both the promoter and the signal sequence of the gene were replaced with those of B. amyloliquefaciens, whereas in another construction only the promoter area was exchanged. The recombinant B. subtilis clones transformed with these plasmid constructions secreted CGTase into the culture medium 14 times as much as did the parental strain in shake flask cultures. In fermentor cultures in an industrially feasible medium the enzyme production was substantially higher, yielding 1.2 g/l of CGTase, which is about 33 times the amount of the enzyme produced by the parental strain in corresponding fermentations. Both of the plasmid constructions were stable when grown over 50 generations without antibiotic selection.

Amino Acid Sequence↗
PubMed1991

Structural and functional analysis of Trichoderma reesei endoglucanase I expressed in yeast Saccharomyces cerevisiae.

The function of the domains of Trichoderma reesei endoglucanase I (EGI) has been studied. Truncated EGI proteins were expressed from the 3'-end deleted cDNAs in the yeast Saccharomyces cerevisiae under the control of the ADC1 expression cassette. EGI protein was detected by monoclonal antibody EI-2 and EGI activity as cleared zones around growing colonies on agar plates containing hydroxyethylcellulose (HEC) covalently stained with Ostazin brilliant red (OBR). The results showed that the The-Ser-rich hinge region and the conserved 'tail' are not necessary for the efficient synthesis and secretion of EGI in yeast, but the intact core region is necessary for the enzymatic activity.

Blotting, Western↗
PubMed1991

Monoclonal antibodies against core and cellulose-binding domains of Trichoderma reesei cellobiohydrolases I and II and endoglucanase I.

Cellulases from Trichoderma reesei form an enzyme group with a common structural organization. Each cellulase enzyme is composed of two functional domains, the core region containing the active site and the cellulose-binding domain (CBD). To facilitate the specific detection of each domain, monoclonal antibodies (mAb) against cellobiohydrolase I (CBHI), cellobiohydrolase II (CBHII) and endoglucanase I (EGI) were produced. Five mAb were obtained against CBHI, ten against CBHII and eight against EGI. The location of the antigenic epitope for each antibody was mapped by allowing the antibodies to react with truncated cellulases, synthesized from deleted cDNA in Saccharomyces cerevisiae. Proteolytic fragments of Trichoderma cellulases, obtained by papain digestion, were used to confirm the results. Specific antibodies were detected against the core and the CBD epitopes for all three cellulases. Using the truncated enzymes, it was possible to locate the epitopes to a reasonably short region within the protein. To obtain a quantitative assay for each enzyme, a specific mAb against each antigen was chosen, based on the affinity to the corresponding antigen on Western-blot staining and on filter blots of the cellulolytic yeasts. The mAb were used to quantitative the corresponding enzymes in T. reesei culture medium. Specific quantitation of each cellulase enzyme has not been possible by biochemical assays or using polyclonal antibodies, due to their cross-reactions. Now, these mAb can be specifically used to recognize and quantitate different domains of these three important cellulolytic enzymes.

Antibodies, Monoclonal↗
PubMed1991

Cloning, sequence and chromosomal location of a MEL gene from Saccharomyces carlsbergensis NCYC396.

Yeast strains producing alpha-galactosidase (alpha Gal) are able to use melibiose as a carbon source during growth or fermentation. We cloned a MEL gene from Saccharomyces carlsbergensis NCYC396 through hybridization to the MEL1 gene cloned earlier from Saccharomyces cerevisiae var. uvarum. The alpha Gal encoded by the newly cloned gene was galactose-inducible as is the alpha Gal encoded by MEL1. A probable GAL4-protein recognition sequence was found in the upstream region of the NCYC396 MEL gene. The gene was transcribed to a 1.5-kb mRNA which, according to the nucleotide sequence, encodes a protein of 471 amino acids (aa) with an Mr of 52,006. The first 18 aa fulfilled the criteria for the signal sequence, but lacked positively charged aa residues, except the initiating methionine. The enzyme activity was found exclusively in the cellular fraction of the cultures. The deduced aa sequence was compared to the aa sequences of other alpha Gal enzymes. It showed 83% identity with the S. cerevisiae enzyme, but only 35% with the plant enzyme, 30% with the human enzyme and 17% with the Escherichia coli enzyme. With pulsed-field electrophoresis, the MEL gene was located on chromosome X of S. carlsbergensis, whereas the S. cerevisiae var. uvarum MEL1 gene is located on chromosome II.

Amino Acid Sequence↗
PubMed1990

The conserved terminal region of Trichoderma reesei cellulases forms a strong antigenic epitope for polyclonal antibodies.

The specificity of polyclonal antibodies (Pab) raised against Trichoderma reesei cellulases has been studied. cDNAs lacking regions coding for certain functional domains were produced by preparing series of 3'-end deletions from the cDNAs for two cellobiohydrolases, CBH I and CBH II, and an endoglucanase, EG I. The proteins coded by the full length cDNAs and the truncated proteins coded by the deleted cDNAs were expressed in yeast Saccharomyces cerevisiae, under the control of the ADC1 promoter. Each polyclonal antiserum showed cross-reactivity with other cellulases. Pabs for CBH I and CBH II both recognized EG I. Pab for EG I strongly recognized both CBH I and CBH II. By analyzing the truncated proteins, we found that these antibodies were almost entirely directed against the conserved tail of the cellulase enzymes.

Antibodies, Fungal↗
PubMed1990

A new family of polymorphic genes in Saccharomyces cerevisiae: alpha-galactosidase genes MEL1-MEL7.

Using genetic hybridization analysis we identified seven polymorphic genes for the fermentation of melibiose in different Mel+ strains of Saccharomyces cerevisiae. Four laboratory strains (1453-3A, 303-49, N2, C.B.11) contained only the MEL1 gene and a wild strain (VKM Y-1830) had only the MEL2 gene. Another wild strain (CBS 4411) contained five genes: MEL3, MEL4, MEL5, MEL6 and MEL7. MEL3-MEL7 were isolated and identified by backcrosses with Mel- parents (X2180-1A, S288C). A cloned MEL1 gene was used as a probe to investigate the physical structure and chromosomal location of the MEL gene family and to check the segregation of MEL genes from CBS 4411 in six complete tetrads. Restriction and Southern hybridization analyses showed that all seven genes are physically very similar. By electrokaryotyping we found that all seven genes are located on different chromosomes: MEL1 on chromosome II as shown previously by Voll-rath et al. (1988), MEL2 on VII, MEL3 on XVI, MEL4 on XI, MEL5 on IV. MEL6 on XIII, and MEL7 on VI. Molecular analysis of the segregation of MEL genes from strain CBS 4411 gave results identical to those from the genetic analyses. The homology in the physical structure of this MEL gene family suggests that the MEL loci have evolved by transposition of an ancestral gene to specific locations within the genome.

Base Sequence↗
PubMed1990

A double-blind randomized placebo trial on very high doses of acyclovir in weakly symptomatic HIV-patients.

Herpesvirus infections are thought to be cofactors of the human immunodeficiency virus (HIV) disease, and high concentrations of acyclovir (ACV) are active on all herpesviruses. Because ACV was shown to delay the cytopathic effect of HIV in vitro, we evaluated the effect of intermittent high doses of ACV in mildly symptomatic HIV-patients in a randomized double-blind placebo-controlled trial with a 4-month treatment period. A total of 30 CDC II and III patients were enrolled; 24 (80%) completed the study. Placebo and ACV were given once a week in a 3-h infusion with 1 g oral probenecid. Each dose of ACV was 50 mg/kg. Pharmacokinetic data were obtained from patients of the preliminary open study. The obtained concentrations were effective against both herpesviruses and HIV: peak concentrations were 197 and 11 mumol/l in serum and CSF, respectively; the CSF:serum ratio of the areas under the curve was 82%. Two patients with placebo acquired hairy leukoplakia and detectable antigenemia vs. none in the ACV group (p = 0.23). T-helper cell count over the 4-month period decreased in the placebo group while it increased in the ACV-treated group (mean of change = -105 c/microliters vs. +68 c/microliters; p = 0.06). beta 2-microglobulin increased with placebo and did not with ACV (mean of change = +0.63 mg/l vs. -0.27 mg/l, p less than 0.025). Only one patient had, at one time, transient elevation of creatinemia related to ACV. We concluded that weekly high doses of ACV were able to delay the progression of some significant markers of HIV disease. Thus, preventive/prophylactic treatment of herpesvirus infections could be useful in mildly symptomatic HIV patients. Further larger trials using a more feasible treatment are warranted.

Acyclovir↗
PubMed1987

Unusual DNA sequences located within the promoter region and the first intron of the chicken pro-alpha 1(I) collagen gene.

Genomic clones corresponding to the amino-terminal propeptide and 5'-flanking sequences of the chicken pro-alpha 1(I) collagen gene were isolated as a first step in the identification of DNA sequences important for transcriptional regulation of the pro-alpha 1(I) collagen gene. Due to the failure to identify positive clones in either primary or amplified genomic libraries, a 5.1-kilobase pair StuI genomic fragment identified by Southern blotting was enriched by sucrose gradient fractionation of genomic DNA and cloned into lambda gt11. Comparison of the DNA sequence of the 5.1-kilobase pair StuI fragment to the DNA sequence of a cDNA clone encoding the amino-terminal propeptide, signal peptide, and the 5'-untranslated region identified the first four exons and most of the fifth. Exon size and intron position have been largely conserved between human and chicken alpha 1(I) genes. DNA sequence analysis of the region 5' to the transcription initiation site identified the canonical TATA and CAAT boxes. However, the 40-nucleotide pyrimidine stretch centered between -150 and -180 nucleotides, found in all previously isolated type I procollagen genes from chicken, mouse, and human, was absent in the chicken pro-alpha 1(I) collagen gene. This sequence corresponds to the in vivo DNase I hypersensitive site in the chicken pro-alpha 2(I) and mouse pro-alpha 1(I) collagen genes, as well as the in vitro S1 nuclease hypersensitive site in both chicken and mouse pro-alpha 2(I) collagen genes. Two unusual DNA sequences were identified within the chicken pro-alpha 1(I) collagen gene. Fifteen tandem repeats of the sequence GGGGAGA were identified within the first intron, 300 nucleotides 3' to the first exon. This sequence was identified due to its hypersensitivity to S1 nuclease in vitro in supercoiled plasmids. The second sequence located 5' to -180 contained at least 25 copies of a polymorphic, 23-base pair tandemly repeated sequence not identified in other type I procollagen genes. Both of these tandem repeat sequences were identified at other locations in the chicken genome by Southern blot hybridization.

Amino Acid Sequence↗
PubMed1984

Location of the 11 bp exon in the chicken pro alpha 2(I) collagen gene.

During the fine structural analysis of the 5' end of the 38 kb chicken pro alpha 2(I) collagen gene, we failed to locate an exon, only 11 bp in size, which had been predicted from the DNA sequence analysis of a cDNA clone complementary to the 5' end of the pro alpha 2(I) collagen mRNA (1). We know report the location of this 11 bp exon, exon 2, at the 5' end of a 180 bp Pst I fragment, 1900 bp 3' to exon 1 and 600 bp 5' to exon 3. Its sequence, ATGTGAGTGAG, is highly unusual in that it contains two overlapping consensus donor splice sequences. Moreover, it is flanked by two overlapping donor splice sequences but only one of the four splice sequences is actually spliced (1). The first half of intron 1 also has an unusual sequence: it is 68% GC, contains 88 CpG dinucleotides and 11 Hpa II sites. The second half is more like other intron sequences in the collagen gene with a GC content of 41%, 19 CpG, and no Hpa II sites. However it contains two sequences with 7 and 9 bp homology to the 14 bp SV40 enhancer core sequence. It is suggested that some part of intron 1 may be involved in regulation.

Animals↗