Molecular cloning of a human genomic region containing the H blood group alpha(1,2)fucosyltransferase gene and two H locus-related DNA restriction fragments. Isolation of a candidate for the human Secretor blood group locus

We have used the human H blood group alpha(1,2)fucosyltransferase (FUT1) cDNA to screen chromosome 19 cosmid libraries in a search for the human Secretor (Se) blood group gene (FUT2). One cosmid has been isolated that contains two distinct segments that cross-hybridize with FUT1. We have assembled a 100-kilobase (kb) cosmid contig, localized to 19q13.3, encompassing FUT1 and the two FUT1-related sequences, termed Sec1 and Sec2, for Secretor candidate 1 and 2. Sec1 and Sec2 are separated by 12 kb and are 65.5 kb and 35 kb apart, respectively, from the FUT1 gene. We used a cosmid-dependent direct cDNA selection method to clone a cDNA corresponding to a transcript that emanates from Sec2. This cDNA detects a 3.35-kb transcript in human tissues known to express the Se locus. Together with sequence and expression data reported in the accompanying article (Kelly, R. J., Rouquier, S., Giorgi, D., Lennon, G. G., and Lowe, J. B. (1995) J. Biol. Chem. 270, 4640-4649), these data demonstrate that Sec2 corresponds to the human Se blood group locus (FUT2). Our results furthermore define the physical relationship between the H and Se loci and confirm a hypothesis that these two loci represent distinct but closely linked alpha(1,2)fucosyltransferase genes.

Relative positions of two clusters of human alpha-L-fucosyltransferases in 19q (FUT1-FUT2) and 19p (FUT6-FUT3-FUT5) within the microsatellite genetic map of chromosome 19

Five on the seven cloned human fucosyltransferase genes have been mapped to two clusters, one on 19q and the other on 19p. Comparative DNA sequence analysis showed the Généthon microsatellite D19S596 lies 2.2 kb downstream of the coding region of FUT1, indicating that the cluster comprising the closely linked FUT1 and FUT2 genes is located 4 cM distal to D19S412 (lod score 13.7) and 9 cM proximal to D19S571 (lod score 11.7). Polymorphic markers of FUT3, FUT5, and FUT6 were used for linkage analysis with 14 Généthon microsatellites in Indonesian families. These three loci constitute a cluster on 19p, located between the Généthon microsatellites D19S216 and D19S567, which are known to be only 1 cM distant from each other. Two cross-overs, one between FUT6 and FUT3 and the other between FUT3 and FUT5, suggest the gene order 19pter-D19S216-FUT6-FUT3-FUT5-D19S567++ +-cen. Comparison of genetic and physical maps suggests that the FUT6-FUT3-FUT5 cluster is located on 19p13.3 and the FUT1-FUT2 cluster on 19q13.3. FUT6, FUT3 and FUT5 genes share more than 85% homology and encode three similar, but distinct alpha(1,3) fucosyltransferases. FUT1 and FUT2 share about 70% homology and encode two distinct alpha(1,2)fucosyltransferases. No sequence homology was found between the genes of the two clusters. The members of each of these two clusters have probably emerged by duplication and divergent evolution of two unrelated ancestor genes.

Molecular basis for Lewis alpha(1,3/1,4)-fucosyltransferase gene deficiency (FUT3) found in Lewis-negative Indonesian pedigrees

The Le(a) and Le(b) human blood group antigens are synthesized in tissues producing exocrine secretions; they also circulate in plasma, where they are adsorbed by erythrocytes. They are synthesized by two fucosyltransferases, encoded by Lewis (FUT3) and secretor (FUT2) loci. This genetic model has been challenged because some erythrocyte Lewis-negative individuals express Lewis antigens in saliva. To define the molecular basis of this apparent discrepancy, we sequenced FUT3 in Lewis-negative individuals. We identified two single base pair changes. One, termed L1, yields a Leu-20-->Arg substitution in the enzyme's transmembrane domain. When expressed in COS-7 cells, enzyme substrate affinities are essentially identical to those of wild type. However, the mutant enzyme is found at substantially reduced levels in transfected cells. This suggests that the L1 mutation may alter the Golgi membrane anchoring of the enzyme. It was found alone in double dose in 10 of 30 erythrocyte Lewis-negative individuals, nine of whom express Lewis antigens in saliva. Therefore, L1 can account for erythrocyte/saliva-discrepant Lewis typing results. The L2 mutation creates an Ile-356-->Lys change in the enzyme's catalytic domain and inactivates the enzyme. It was found in double dose in 18 of 19 individuals bearing the double erythrocyte and salivary Lewis deficiency and can account for this phenotype.

Molecular basis for H blood group deficiency in Bombay (Oh) and para-Bombay individuals

The penultimate step in the biosynthesis of the human ABO blood group oligosaccharide antigens is catalyzed by alpha-(1,2)-fucosyltransferase(s) (GDP-L-fucose: beta-D-galactoside 2-alpha-L-fucosyltransferase, EC 2.4.1.69), whose expression is determined by the H and Secretor (SE) blood group loci (also known as FUT1 and FUT2, respectively). These enzymes construct Fuc alpha 1-->2Gal beta-linkages, known as H determinants, which are essential precursors to the A and B antigens. Erythrocytes from individuals with the rare Bombay and para-Bombay blood group phenotypes are deficient in H determinants, and thus A and B determinants, as a consequence of apparent homozygosity for null alleles at the H locus. We report a molecular analysis of a human alpha-(1,2)-fucosyltransferase gene, thought to correspond to the H blood group locus, in a Bombay pedigree and a para-Bombay pedigree. We find inactivating point mutations in the coding regions of both alleles of this gene in each H-deficient individual. These results define the molecular basis for H blood group antigen deficiency in Bombay and para-Bombay phenotypes, provide compelling evidence that this gene represents the human H blood group locus, and strongly support a hypothesis that the H and SE loci represent distinct alpha-(1,2)-fucosyltransferase genes. Candidate sequences for the human SE locus are identified by low-stringency Southern blot hybridization analyses, using a probe derived from the H alpha-(1,2)-fucosyltransferase gene.

Molecular basis for plasma alpha(1,3)-fucosyltransferase gene deficiency (FUT6)

While most humans express an alpha(1,3)-fucosyltransferase in plasma, 9% of individuals on the isle of Java (Indonesia) do not express this enzyme. Ninety-five percent of these plasma alpha(1,3)-fucosyltransferase-deficient individuals have Lewis negative phenotype on red cells, suggesting strong linkage disequilibrium between these two traits. To define the molecular basis for this plasma deficiency and to determine which of two candidate human alpha(1,3)-fucosyltransferase genes encode this enzyme (FUT5 and FUT6), we cloned and analyzed alleles at these two loci from an Indonesian individual deficient in plasma alpha(1,3)-fucosyltransferase activity. Single base pair changes were identified in the coding region of each gene, relative to previously published wild type alleles. These changes in turn yield three codon changes in FUT5 and three in FUT6. The codon changes in the FUT5 gene do not yield detectable diminutions in alpha(1,3)-fucosyltransferase activity when tested by expression in transfected COS-1 cells, and none of the FUT5 alleles co-segregate with plasma alpha(1,3)-fucosyltransferase deficiency in Indonesian pedigrees. By contrast, two of the codon changes in the FUT6 alleles inactivate this gene when tested by expression in transfected COS-1 cells. One of these inactivating changes is a missense mutation (Glu-247-->Lys) within the enzyme's catalytic domain. The other inactivating mutation represents a nonsense mutation (Tyr-315-->stop) that truncates the COOH terminus of the enzyme by 45 amino acids. The Glu-247-->Lys missense mutation is present in double dose in the nine plasma alpha(1,3)-fucosyltransferase-deficient individuals tested, whereas the nonsense mutation at tyrosine 315 is present in double dose in just one of these persons. These results demonstrate that the alpha(1,3)-fucosyltransferase activity in human plasma is encoded by the FUT6 gene and that the missense mutation within codon 247 of this gene is responsible for deficiency of this activity in these Indonesian families.

Children's patterns of disclosures and recantations of sexual and ritualistic abuse allegations in psychotherapy

Patterns of disclosures and recantations of abuse made in psychotherapy were examined in a sample of 63 children who reported sexual and ritualistic abuse in a preschool setting. Therapists completed a measure that instructed them to identify the time since the child began therapy when any disclosures or recantations were made, to specify the type of abuse disclosed or recanted, and to identify any events that might be related to the timing of a disclosure or recantation. The findings revealed that the majority of subjects (76.2%) disclosed abuse within the first month of therapy. Recantation occurred in 17 cases (27%) and all but two children who recanted redisclosed abuse after the initial recantation. There was some evidence that children's experiences within the legal system may have been associated with recantations. Subjects tended to make vague disclosures before revealing more specific acts, reveal less intrusive sexual abuse (e.g., kissing) before more intrusive types (e.g., intercourse), and to disclose ritualistic abuse after other types.

Molecular cloning of a fourth member of a human alpha (1,3)fucosyltransferase gene family. Multiple homologous sequences that determine expression of the Lewis x, sialyl Lewis x, and difucosyl sialyl Lewis x epitopes

We and others have previously described the isolation of three human alpha (1,3)fucosyltransferase genes which form the basis of a nascent glycosyltransferase gene family. We now report the molecular cloning and expression of a fourth homologous human alpha (1,3)fucosyltransferase gene. When transfected into mammalian cells, this fucosyltransferase gene is capable of directing expression of the Lewis x (Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc), sialyl Lewis x (NeuNAc alpha 2-->3Gal beta 1-->4 [Fuc alpha 1-->3]GlcNAc), and difucosyl sialyl Lewis x (NeuNAc alpha 2-->3Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc beta 1-->3 Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc) epitopes. The enzyme shares 85% amino acid sequence identity with Fuc-TIII and 89% identity with Fuc-TV but differs substantially in its acceptor substrate requirements. Polymerase chain reaction analyses demonstrate that the gene is syntenic to Fuc-TIII and Fuc-TV on chromosome 19. Southern blot analyses of human genomic DNA demonstrate that these four alpha (1,3)fucosyltransferase genes account for all DNA sequences that cross-hybridize at low stringency with the Fuc-TIII catalytic domain. Using similar methods, a catalytic domain probe from Fuc-TIV identifies a new class of DNA fragments which do not cross-hybridize with the chromosome 19 fucosyltransferase probes. These results extend the molecular definition of a family of human alpha (1,3)fucosyltransferase genes and provide tools for examining fucosyltransferase gene expression.

Molecular cloning of a human fucosyltransferase gene that determines expression of the Lewis x and VIM-2 epitopes but not ELAM-1-dependent cell adhesion

We have used the human Lewis blood group fucosyltransferase cDNA and cross-hybridization procedures to isolate a human gene that encodes a distinct fucosyltransferase. Its DNA sequence predicts a type II transmembrane protein whose sequence is identical to 133 of 231 amino acids at corresponding positions within the catalytic domain of the Lewis fucosyltransferase. When expressed by transfection in cultured cell lines, this gene determines expression of a fucosyltransferase capable of efficiently utilizing N-acetyllactosamine to form the Lewis x determinant (Gal beta 1----4[Fuc alpha 1----3]GlcNAc). By contrast, biochemical and flow cytometry analyses suggest that the enzyme cannot efficiently utilize the type II acceptor NeuNAc alpha 2----3Gal beta 1----4GlcNAc, to form the sialyl Lewis x determinant. In Chinese hamster ovary cells, however, the enzyme can determine expression of the alpha 2----3-sialylated, alpha 1----3-fucosylated structure known as VIM-2, a putative oligosaccharide ligand for ELAM-1. Cell adhesion assays using VIM-2-positive, sialyl Lewis x-negative transfected Chinese hamster ovary cells indicate that surface expression of the VIM-2 determinant is not sufficient to confer ELAM-1-dependent adhesive properties upon the cells. These results demonstrate that substantial structural similarities can exist between mammalian glycosyltransferases with closely related enzymatic properties, thus facilitating isolation of their cognate genes by cross-hybridization methods. The results further suggest that cell surface expression of the VIM-2 determinant is not necessarily sufficient to mediate ELAM-1-dependent cell adhesion.

The Cucurbita maxima ribosomal DNA intergenic spacer has a complex structure

The nucleotide (nt) sequence of the 5508-nt intergenic spacer (IGS), between the 25S- and the 18S-coding regions of Cucurbita maxima rDNA, was determined. The fragment sequenced is 6142 nt long and includes 472 nt of 25S- and 162 nt of 18S-coding regions. The IGS has a complex primary structure, composed of five repetitive families (A-E) and three unique domains. It is dominated by the presence of nine, tandemly-repeating units of approximately 250 nt (repeat D), each unit containing four copies of an internal subrepeat (repeat E). The repetitive units show sequence variability consisting of nt changes, insertions and deletions. Upstream of the nine D repeats and between two copies of the B repeat is a 575-nt region, highly G + C rich (83%) and heavily biased toward C (58%) in the sense strand. Within this region are six repetitive units, averaging 42 nt (repeat C) each, containing but a single A nt. Downstream from the terminus of the 25S-coding sequence, are two tandem copies of the 103-nt A repeat. The IGS of C. maxima is longer and more complex than that of other plant IGSs described to date. The 600 nt at the 5' portion of cucurbit IGS is more conserved in evolution than the remainder, as revealed by comparison of C. maxima and C. pepo IGS restriction maps and by nucleotide sequence comparison of C. maxima and Cucumis sativa IGSs.

Radiographic effects of cold barium suspensions on esophageal motility

The effects of cold barium solutions on esophageal motility were studied in 70 patients. Baseline esophageal peristalsis was assessed using barium at room temperature. Twenty-eight patients were then re-examined when chilled barium (4 degrees C) was used and results showed a 45% reduction of primary peristalsis. Forty-two patients were re-assessed when iced barium (3 degrees C) was used and results showed a 58% reduction.

Efficacy of radionuclide scanning in patients with lung cancer

Ninety-two patients with histologically proved carcinoma of the lung were studied retrospectively to determine the usefulness of liver, brain, and bone imaging in their examination and treatment. Occult metastatic liver disease was observed in two (5.3%) of 38 asymptomatic patients, while four (6.6%) of 58 neurologically intact patients had abnormal brain scans. Eight (13.6%) of 59 asymptomatic patients had metastatic bone disease. Seven (18.4%) of 38 patients with no clinical evidence of metastatic disease to liver, brain, or bone had at least one type of abnormal radionuclide study. More than half (52.5%) of the patients studied had at least one abnormal scan exclusive of symptoms. Radionuclide imaging is a useful procedure in the initial evaluation and subsequent management of lung cancer.

Comparison of Tc-99m pyrophosphate and Tc-99m methylene diphosphonate in acute myocardial infarction: concise communication

This study compared Tc-99m pyrophosphate (PPi) and Tc-99m methylene diphosphonate (MDP) for myocardial infarct imaging in 24 patients with diagnosed acute myocardial infarction. The radiopharmaceuticals were administered randomly and interpreted without knowledge of the sequence used. Twenty-three patients (96%) had positive Tc-99m PPi scintigrams, but only 17 (71%) had a positive Tc-99m MDP study (P less than 0.05). In addition, a comparison of the relative intensity with each agent revealed greater intensity with Tc-99m in 21 cases, equal intensity in two cases, and less intensity in only one case (p less than 0.001). These findings support the superiority of Tc-99m PPi as the agent of choice for myocardial scintigraphy in acute infarction.

Keratophakia: a preliminary evaluation

The results of 18 cases of combined cataract extraction and keratophakia are presented. Initial results indicate that these procedures may replace the use of alloplastic materials for the correction of aphakic ametropia either as a primary or a secondary procedure.

Effect of autonomic neural blockade on verapamil-induced suppression of the accelerated ventricular escape beat in ouabain-treated dogs

The effect of autonomic neural blockade on verapamil-induced suppression of the accelerated ventricular escape beat (AVE) was evaluated in anesthetized dogs pretreated with ouabain. Ouabain (53 +/- 2 microgram/kg, n = 45) was administered in divided doses until simultaneous electrical stimulation of the right atrium and ventricle triggered an AVE. The escape interval of the AVE was stable over a 150-min time period in a group of control animals. Verapamil was infused (20 microgram/kg/min) until the escape interval increased at least 50% or until the AVE was abolished. The total amount of verapamil in milligrams per kilogram that produced this effect was defined as the verapamil endpoint. The verapamil endpoint in vagotomized animals was not significantly different from a group of intact controls. In contrast, the verapamil endpoint in animals pretreated with propranolol, hexamethonium, guanethidine, bretylium or spinal section was significantly less than the control group. Propranolol, hexamethonium, guanethidine or spinal section alone increased the escape interval by a maximum of 12%. Infusion of norepinephrine in spinal animals treated with verapamil restored the AVE. These data indicate that sympathetic nerve activity contributes to the genesis of the AVE and antagonizes the antiarrhythmic effect of verapamil on the escape beat.

Effects of cannabis intoxication on primary suggestibility

Thirty-five subjects of known hypnotizability were tested for primary suggestibility in the waking state with and without marijuana intoxication. The drug caused an increase in suggestibility similar to that produced by the induction of hypnosis. The effect did not persist when subjects were retested one week later in their normal waking state.

Comparison of the antiarrhythmic activity of quinidine and quinine

A comparison was made between the effects of quinidine and quinine on experimental arrhythmias and on cardiac electrophysiologic parameters. Both drugs raised ventricular fibrillation thresholds, reversed aconitine-induced atrial fibrillation, decreased ouabain-induced abnormal ventricular beats, and increased atrial refractory periods and His-Purkinje conduction time. In contrast, only quinidine antagonized acetylcholine-induced atrial fibrillation. In addition, quinidine increased ventricular fibrillation thresholds and atrial refractory periods for a longer time period than quinine. These observations are discussed in terms of choosing an appropriate model for testing new compounds with suspected quinidine-like activity.

Localization of 99mTc-Sn-pyrophosphate in left ventricular aneurysms

Concentration of 99mTc-pyrophosphate (99mTc-PPi) in the area of left ventricular aneurysms is discussed. In three cases clinical, laboratory, and electrocardiographic (ECG) evidence did not indicate that these patients currently had an acute myocardial infarction, but each patient had a clinical history and an ECG picture compatible with an old myocardial infarction. Cardiac catheterization revealed a large left ventricular aneurysm in all three cases. The reason for the preferential uptake of the radionuclide in the area of these aneurysms is not certain at this time.

An improved fluorescence probe cytotoxicity assay

The phenanthridine dye, ethidium bromide, which is actively excluded by viable cells, undergoes a significant fluorescence enhancement at 5900 A upon binding intracellular double-stranded polyribonucleotides. A rapid and sensitive assay of antibody mediated cytotoxicity to cells grown in vitro has been developed using this phenomenon. In this communication, we describe this fluorescence probe cytotoxicity assay and a sensitive electro-optical system designed to measure the fluorescence enhancement of ethidium bromide as it intercalates with intracellular polyribonucleotides. Basic characteristics of the fluorescence enhancement resulting from the interaction of ethidium bromide and non-viable cells are presented as well as examples of this assay as it has been used to study surface membrane neoantigens of cells tranformed by the oncogenic DNA virus, SV40.