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R Male

Publications and source records attributed to R Male.

At least 19 recordsLinked to original sources
PubMed2000

[Current methods of molecular cytogenetics in pre- and postnatal diagnosis of chromosome aberrations].

Progress in prevention of chromosome aberrations is due to utilization of molecular cytogenetic diagnostic methods. The purpose of this trend of clinical cytogenetics is development and utilization of new highly effective methods for analysis of chromosome aberrations. Molecular cytogenetic methods (fluorescent in situ hybridization-FISH) are used for pre- and postnatal identification of chromosome aberrations in mentally retarded children and congenital diseases. These studies are carried out after classical cytogenetic analysis, if it proves to be of no avail. FISH diagnosis pre- and postnatally detects autosomal trisomy, gonosome aneuploidy (including mosaic forms), marker chromosomes, structural chromosome aberrations, including fragile X chromosome syndrome. Rapid (15-30 min) FISH with an original collection of centromere, telomere, and site-specific DNA probes (plasmid, cosmid, PAC and YAC clones) is recommended for molecular cytogenetic diagnosis. FISH diagnosis is an effective complex of methods for pre- and postnatal identification of chromosome aberrations and a necessary supplement to classical cytogenetic diagnosis. Molecular studies of chromosome aberrations are significant for theoretical and applied studies, for they help detect patients with specific chromosome syndromes from a vast group of children with undifferentiated mental retardation and congenital diseases.

Aneuploidy↗
PubMed1999

Induction of hepatic estrogen receptor in juvenile Atlantic salmon in vivo by the environmental estrogen, 4-nonylphenol.

Alkylphenol ethoxylate degradation products such as nonylphenol and octylphenol are shown to have estrogenic effects. Nonylphenol induces synthesis of vitellogenin (a precursor of egg yolk proteins) and zona radiata proteins (eggshell proteins) in juvenile and/or male fish. Little is known about the molecular mechanisms of estrogenicity of environmental chemicals such as nonylphenol. To study the mechanisms of estrogenic effects of 4-nonylphenol (NP), we examined its in vivo effects on the expression of the estrogen receptor (ER), vitellogenin (Vtg) and zona radiata protein (Zrp) genes in juvenile Atlantic salmon liver. We show that the ER mRNA synthesis is induced by NP in a dose-dependent manner in juvenile Atlantic salmon liver. The induction of the ER mRNA synthesis is followed by the induction of Zrp and Vtg mRNA synthesis. The ER transcripts reach peak levels earlier than the Zrp and Vtg mRNA and proteins, which is in agreement with the physiological effects of estradiol during zonagenesis and vitellogenesis. Various studies have also shown that NP competitively inhibits the binding of 17 beta-estradiol (E2) to ER. Our results further suggest that NP directly mimics E2 in inducing the ER, Zrp and Vtg genes in salmon liver.

Animals↗
PubMed1999

Salmon Eggshell Protein Expression: A Marker for Environmental Estrogens.

: A liver complementary DNA expression library from Atlantic salmon (Salmo salar) pretreated with estradiol-17beta (E2) was constructed and screened with antibodies raised against salmon eggshell (zona radiata) proteins. Two clones, SalZr2_19 and SalZr2_23 were sequenced and shown to encode proteins of approximately 50 kDa. SalZr2_23 contains 12 octamer sequence lpqr/kpa/vq repeats also found in SalZr2_19, but only twice. Alignment reveals that the two salmon sequences are similar to piscine zona radiata proteins and mammalian zona pellucida proteins. Several transcripts ranging from 2.3 to 12 kb appeared in liver extracts of E2-treated fish. Juvenile fish treated with E2 or 4-nonylphenol showed strong induction of zona radiata protein. The use of egg envelope transcriptional and translational induction in male or juvenile fish as a biological marker of environmental estrogens is discussed.

Journal Article↗
PubMed1998

Endoscopic sphincterotomy for stones by experts is safe, even in younger patients with normal ducts.

OBJECTIVE: To provide current information on the risks of endoscopic sphincterotomy for stone. SUMMARY BACKGROUND DATA: In recent years (since the popularity of laparoscopic cholecystectomy), endoscopic sphincterotomy has been used increasingly for the management of bile duct stones in relatively young and healthy patients. The validity of this trend has been questioned using data on short-term complications derived from earlier decades that involved more elderly and high-risk patients. METHODS: Seven academic centers collected data prospectively using a common database. Complications within 30 days of the procedures were documented by standard criteria. RESULTS: Of 1921 patients, 112 (5.8%) developed complications; two thirds of these events were graded as mild (<3 days in hospital). There was no evidence of increased risk in younger patients or in those with smaller bile ducts. There was only one severe complication and there were no fatalities in 238 patients age <60, with bile duct diameters of <9 mm. CONCLUSION: Sphincterotomy for stones can be performed very safely by experienced endoscopists.

Age Factors↗
PubMed1996

Two variants of the pituitary specific transcription factor Pit-1 in Atlantic salmon.

We have cloned two 1.6 kb cDNAs encoding variants of the POU-type pituitary-specific transcription factor Pit-1 from Atlantic salmon. Sequence comparison with mammalian Pit-1 revealed that the POU domain was highly similar while flanking regions were less conserved. The N-terminal region contained three insertions relative to mammalian Pit-1, one of these corresponded to the insertion found in the alternatively spliced Pit-1a isoform. While two different salmon Pit-1 transcripts were expressed, alternative splicing in the 5'-region did not appear to contribute to further transcript diversity. Both salmon Pit-1 cDNAs encoded 39.5 kDa proteins that specifically bind a consensus Pit-1 recognition sequence in vitro. The salmon Pit-1 proteins also recognized the classical octamer motif; however, a point mutation in the POU homeodomain abolished this interaction.

Alternative Splicing↗
PubMed1995

Molecular cloning and characterization of anionic and cationic variants of trypsin from Atlantic salmon.

Pancreatic cDNA libraries from Atlantic salmon (Salmo salar) were constructed and screened with salmon trypsin-specific probes. Five clones containing near full-length transcripts were selected for further characterization. Comparison of deduced amino acid sequences revealed that all variants possessed the canonical serine protease catalytic triad, consisting of histidine, aspartic acid and serine residues, a substrate-binding pocket with aspartic acid at the bottom, and 12 cysteine residues comprising six disulphide bridges. Translation in vitro of one of the trypsin clones produced a protein with the expected molecular mass of 24.5 kDa. Three of the Atlantic salmon trypsins (SalTRP-I, SalTRP-IA and SalTRP-IB) possessed very similar sequences and may represent allelic variants encoded by the same gene focus; however, existence as tetraploid loci or isoloci where disomic inheritance is incomplete may also exist in Atlantic salmon and cannot be excluded. Two other trypsin clones (SalTRP-II and SalTRP-III) are probably encoded by separate gene loci. Analysis of genomic DNA by Southern blotting and hybridization to a trypsin probe showed a complex pattern, indicative of a large number of gene loci for trypsin in Atlantic salmon. The charged amino acid distribution showed that four of the Atlantic salmon trypsin clones encoded anionic forms of the enzyme, while the fifth clone represented a cationic variant. Multiple alignments of the Atlantic salmon trypsin sequences with trypsin, chymotrypsin and elastase from different species placed all Atlantic salmon sequences approximately equidistant from trypsins of other species. Interestingly, the distance between the anionic and cationic variants from Atlantic salmon was similar to the distance between salmon and mammalian trypsins, revealing an early separation of these two types of trypsin, possibly prior to the derivation of fish during evolution. A structural model based on X-ray diffraction studies of the salmon trypsin protein was very similar to that of the mammalian enzyme. All residues which differ in charge between anionic and cationic trypsins were located at exposed regions of the proteins.

Amino Acid Sequence↗
PubMed1994

Pancreatic carboxylester lipase from Atlantic salmon (Salmo salar). cDNA sequence and computer-assisted modelling of tertiary structure.

We report the isolation and characterization of a 1795-bp cDNA fragment encoding Atlantic salmon pancreatic carboxylester lipase from salmon pancreas mRNA. The nearly full-length cDNA contained a 540-amino-acid open-reading frame, encompassing the mature protein (by similarity to mammalian carboxylester lipase enzymes). The salmon carboxylester lipase primary structure shared 58% identity with mammalian carboxylester lipases, lacking the proline-rich C-terminal repeats found in human and rat carboxylester lipases. Congruent with other esterase B type enzymes, the salmon carboxylester lipase contained a canonical serine-esterase catalytic triad motif consisting of serine, histidine and aspartic acid. Computer-assisted modelling of the tertiary structure for salmon carboxylester lipase was conducted using acetylcholine esterase (Torpedo californica) as a template structure. The model, in conjunction with sequence comparisons and available enzymological data, has been used to locate putative bile-salt-binding and lipid-binding sites. The carboxylester lipase enzymes contain a unique, highly conserved insert region that may be associated with bile-salt binding. In the model structure, this region is located close to the active site, and contains a tyrosine residue with an adjacent carboxylester-lipase-conserved arginine. These traits have previously been predicted for the non-specific (regarding bile-salt hydroxylation) bile-salt-binding site in carboxylester lipase enzymes. At this site, a dihydroxy or trihydroxy bile-salt molecule may bind the tyrosine via hydrophobic interactions, the anionic bile-salt head group may bind the arginine, while hydrogen bonding between the bile-salt 12 alpha hydroxy group and an adjacent aspargine residue is possible. The model does not contain an active site 'lid' structure as found in other lipases. The carboxylester lipase structural homolog to the 'flap' of the lipases from Geotrichum candidum and Candida rugosa contains a carboxylester-lipase-conserved deletion that renders this region unable to cover the active site. Instead, the shortening of this loop leads to solvent exposure of the carboxylester lipase insert region, an additional indication of the functional importance of this region.

Amino Acid Sequence↗
PubMed1994

Cold adaption of enzymes: structural comparison between salmon and bovine trypsins.

The crystal structure of an anionic form of salmon trypsin has been determined at 1.82 A resolution. We report the first structure of a trypsin from a phoikilothermic organism in a detailed comparison to mammalian trypsins in order to look for structural rationalizations for the cold-adaption features of salmon trypsin. This form of salmon trypsin (ST II) comprises 222 residues, and is homologous to bovine trypsin (BT) in about 65% of the primary structure. The tertiary structures are similar, with an overall displacement in main chain atomic positions between salmon trypsin and various crystal structures of bovine trypsin of about 0.8 A. Intramolecular hydrogen bonds and hydrophobic interactions are compared and discussed in order to estimate possible differences in molecular flexibility which might explain the higher catalytic efficiency and lower thermostability of salmon trypsin compared to bovine trypsin. No overall differences in intramolecular interactions are detected between the two structures, but there are differences in certain regions of the structures which may explain some of the observed differences in physical properties. The distribution of charged residues is different in the two trypsins, and the impact this might have on substrate affinity has been discussed.

Acclimatization↗
PubMed1993

Organ distributions of liposome-loaded rat platelets.

Past in vitro functional assays have demonstrated that platelet function is not inhibited by liposome uptake. In the present study, the organ distributions of control and liposome-loaded Sprague-Dawley rat platelets were examined to determine whether liposome uptake enhances RES uptake. Platelets were isolated using STRactan density gradient centrifugation, incubated with small unilamellar liposomes in vitro for 1 hour, labeled with 51Cr and injected into a cohort group of rats. One hour post-injection the spleen, liver, lungs, blood, kidneys and bladder contents were removed and the percentages of the recovered dose localized per total organ (%RD) were determined. The RES index, defined as %RDliver + %RDspleen, were 24.8 +/- 4.5 and 20.5 +/- 5.0 for the control platelets and liposome-loaded platelets, respectively. These results indicate that liposome uptake does not enhance RES uptake.

Animals↗
PubMed1993

Expression of growth hormone genes in Atlantic salmon.

Atlantic salmon (Salmo salar) possess two genes encoding GH. We have investigated the expression of these two genes in the salmon pituitary. The transcriptional start site was localized 64 nucleotides upstream of the first methionyl codon using primer extension and 5' specific polymerase chain reaction (PCR) assays. Northern analysis revealed a major Atlantic salmon GH (salGH) transcript band of approximately 1400 nucleotides. As coexpression of the salGH genes is not discernible by transcript length, other techniques were used to assess gene activity; RNase protection analysis revealed GH transcript heterogeneity, while reverse transcription-PCR assays detected transcripts from both genes at approximately equivalent amounts. The encoded salGH protein, generated in vitro and by Escherichia coli, shares electrophoretic and immunoreactive identity with native pituitary salGH.

Animals↗
PubMed1992

Phagocytosis of liposomes by human platelets.

We have shown that platelets are capable of phagocytosing liposomes rather than simply sequestering particles as previously postulated. Incubation of human platelets with small neutral unilamellar liposomes (approximately 74 nm) resulted in uptake of the liposomes and retention of the lipid with rapid release of the aqueous-phase components. The lipid label [3H]-cholesterylhexadecyl ether and water-soluble [3H]inulin were used to study the fate of the liposome components. Uptake of liposomes was proportional to the number of liposomes added and to the incubation time. Approximately 250 liposomes per platelet were taken up within a 5-hr incubation period. Uptake of the liposomes occurred through the open-channel system, as evidenced by thin-section electron microscopy, and was followed by accumulation and degradation in acid- and esterase-containing vesicles, as determined by changes in fluorescence of the pH-sensitive probe, pyranine (1-hydroxypyrene-3,6,8-trisulfonic acid), and hydrolysis of the cholesteryl [14C]oleate membrane marker. Uptake was inhibited by the addition of EDTA, cytochalasin B, or 2,4-dinitrophenol and iodoacetate to the medium. Results from the serotonin release assay, micro-aggregation assay, fluorescein diacetate membrane integrity assay, and electron microscopy indicate that neither the conditions for loading nor phagocytosis of liposomes significantly alter platelet function or morphology.

Blood Platelets↗
PubMed1992

The complete nucleotide sequence of the Atlantic salmon growth hormone I gene.

Two closely related genes encoding growth hormone were isolated from Atlantic salmon by genomic cloning. From one of these genes a total of 6500 nucleotides were determined including 3900 nucleotides in exons and introns and about 600 and 2000 nucleotides in 5' and 3' flanking regions. The gene is organized in six exons and encodes a polypeptide of 210 amino acids including a 22 amino acids signal sequence. The promoter region contains a typical TATA box 21 nucleotides upstream from the transcription start site. At the 3' end, three putative poly(A) signal sequences are present. The last two are within a 121 nt inverted repeat.

Amino Acid Sequence↗
PubMed1992

Cloning and sequence analysis of two isotypic IgM heavy chain genes from Atlantic salmon, Salmo salar L.

A leukocyte cDNA library from Atlantic salmon, based on oligo-dT priming, was constructed in lambda-gt10. Immunoglobulin heavy chain (IgH) cDNA were isolated from the library using a specific probe generated by polymerase chain reaction (PCR) between two conserved areas within the variable region (second and fourth frame region). Two cDNA clones encoding the entire constant region of membrane-bound IgH, and one cDNA encoding the entire constant region of secretory IgH were sequenced, revealing messages from two isotypic IgM genes. Both genes were shown to be present in haploid embryos and have been isolated from a genomic library, the exons and deduced amino acid sequences of which are presented here (salmon CHA and CHB). The splicing of transcripts encoding the membrane-bound IgH excises the whole fourth exon as in other teleosts. The nucleotide and amino acid identity between salmon CHA and CHB are 98.2%, and 96.2%, respectively. Two subfractions of IgM from Atlantic salmon separated by ion chromatography can be explained by a net exchange of basic residues in salmon CHB compared to CHA. The finding of two closely related salmon CH genes is in accordance with the quasi-tetraploid state of the Atlantic salmon genome.

Amino Acid Sequence↗
PubMed1992

Cirrhosis: diagnosis by liver surface analysis with high-frequency ultrasound.

To determine the sensitivity, specificity, and predictive values of the sonographic analysis of liver surface irregularities for the diagnosis of cirrhosis, the authors conducted a prospective and blinded study in 70 subjects with abnormal liver function tests. All patients included underwent liver biopsy within 15 days of the sonographic study. Twenty-three subjects with no signs or symptoms of liver disease were examined to assess the sonographic appearance of normal liver surface. Studies were performed with a small-parts probe, high-frequency transducer (7.5 MHz). Three basic patterns of liver surface were found: type I, normal; type II, focal abnormality; and type III, diffuse irregularity. Considering diffuse surface irregularity as an objective sonographic sign of cirrhosis, the study's sensitivity was 87.5%, specificity 81.5%, and positive and negative predictive values were 80% and 88.5%, respectively. Disease prevalence for cirrhosis was 45%. We conclude that sonographic analysis of the liver surface is a useful noninvasive test for the diagnosis of cirrhosis in the appropriate clinical setting.

Adult↗
PubMed1989

Platelet-derived-growth-factor-stimulated heterogeneous polyphosphoinositide metabolism and phosphate uptake in C3H fibroblasts.

Pig platelet-derived growth factor (PDGF) increased the rate of [32P]Pi uptake by murine fibroblasts, resulting in a 3-9-fold elevation of the specific radioactivity of ATP, PtdInsP, PtdInsP2, PtdIns and phosphatidic acid. The specific radioactivity was 10-60-fold higher in ATP than in the four phospholipids. These substances are therefore not in metabolic equilibrium, which complicates determination of inositol phospholipid turnover.

Adenosine Triphosphate↗
PubMed1988

Expression of oncogenes in thyroid tumours: coexpression of c-erbB2/neu and c-erbB.

The receptor-type oncogenes c-erbB2/neu and c-erbB have been found amplified and/or overexpressed in a number of tumours of epithelial origin. We have studied the expression of oncogenes in biopsies from human thyroid tumours. The c-erbB2/neu and c-erbB oncogenes showed two- to three-fold higher levels of RNA in papillary carcinomas and lymph node metastases as well as in one adenoma when compared to non-tumour tissue. The nuclear oncogenes c-myc and c-fos were found to be expressed at varying levels in both non-tumour and tumour tissue. RNA transcripts specific for the platelet-derived growth factor A and B chains and the N-ras oncogene were detected in one anaplastic carcinoma. Neither rearrangements nor amplifications of oncogenes were observed in the thyroid tumours. These data are particularly interesting in light of the recent findings that epidermal growth factor induces proliferation and dedifferentiation of normal thyroid epithelial cells in vitro. We suggest that the epidermal growth factor or other ligands for the c-erbB and c-erbB2/neu receptors may contribute to the development and/or maintenance of the malignant phenotype of papillary carcinomas of the thyroid.

Adenoma↗