Infrequent mutations of the TP53 gene and no amplification of the MDM2 gene in hepatoblastomas

We have investigated the mutation of the TP53 gene in hepatoblastomas (HBLs) by using polymerase chain reaction-single strand conformation polymorphism and direct sequencing in 38 HBL tumor samples and in two HBL cell lines. We detected the TP53 gene mutation in an anaplastic hepatoblastoma cell line, but no aberration of the TP53 gene (exons 5-9) was found in tumor samples and in the other HBL cell line. The mutation of the cell line was a missense mutation from GAC (asparagine) to CAC (histidine) at codon 281, which was different from the G-to-T transversion of codon 249 that is frequently found in adult hepatocellular carcinomas (HCCs). In addition, we performed Southern blot analysis of the MDM2 gene, but we did not find MDM2 gene amplification in 19 cases tested. Our results suggest that, in contrast to the findings in HCCs in adults, TP53 gene aberrations are not involved in the development or progression of HBLs in children.

[Long QT syndrome]

Romano-Ward syndrome, one of familial long QT syndromes, is an inherited disorder that causes sudden death from cardiac arrhythmias, specifically torsade de pointes and ventricular fibrillation. By linkage analyses, three LQT loci were previously mapped: LQT1 on chromosome 11p15.5, LQT2 on 7q35-36, LQT3 on 3p21-24. It was recently brought to light that LQT2 and LQT3 were caused by mutations of the gene encoding cardiac ion channels. Mutations in HERG on chromosome 7q35-36, encoding potassium channels (Ikr), cause LQT2, and block of Ikr is a known mechanism for drug-induced prolongation of cardiac action potentials, which provides a mechanistic link between LQT2 and certain forms of acquired LQT. Mutations in SCN5A on chromosome 3p21, encoding the human heart voltage-gated sodium-channel alpha-subunit, cause LQT3. Mutant channels show a sustained inward sodium current during membrane depolarization, which explains prolongation of cardiac action potentials.

Mesial temporal lobe epilepsy: clinical features and seizure mechanism

To study the clinical features of mesial temporal lobe epilepsy, 24 cases were selected based on two criteria: (a) the origin of seizure was localized to the mesiotemporal region on phase 2 monitoring, and (b) a class 1 or 2 postoperative result was obtained after selective mesiotemporal resection. A history of febrile convulsion, particularly in the form of status epilepticus, seems to be a prognostic factor. As for presurgical evaluation, electroencephalography (EEG), magnetic resonance imaging (MRI), magnetoencephalography (MEG), and ictal single-photon emission-computed tomography (SPECT) are important tests. Recording of spontaneous seizures by means of intracranial electrodes is the most reliable for diagnosis. Ammon's horn sclerosis and mesial temporal sclerosis are the most frequent pathologic findings. The seizure mechanism was studied by means of depth EEG recordings and ictal SPECT. The hippocampal formation is more responsible than the amygdala for the origin of seizures. Preferential pathways for seizure spread may be the fornix and stria terminalis, amygdalofugal fibers, and uncinate fasciculus. The concept of mesial temporal lobe epilepsy is valid for selecting medically refractory but surgically remediable patients for surgical treatment.

[Cardiomyoplasty effectiveness: review of the mechanism]

The effectiveness of cardiomyoplasty on cardiac function is discussed, and the four mechanisms proposed to explain cardiomyoplasty effectiveness are reviewed. The first such mechanism, termed the squeezing effect, suggests that skeletal muscle wrapped around the heart squeezes the heart in the same way as cardiac massage, resulting in direct improvement in cardiac function. Hemodynamic improvement is rarely detectable, but significant subjective improvement is commonly seen clinically. The second mechanism, termed the sparing effect, suggests that even if cardiac performance remains unchanged after cardiomyoplasty, contraction of the wrapped lattisimus dorsi muscle causes an increase in the slope of the end-systolic pressure-volume relationship, and a reduction in left ventricular wall stress. Myocardial oxygen consumption is thereby reduced. The third mechanism, called the girdling effect, suggests that cardiomyoplasty may act like an elastic girdle around the heart to prevent enlargement of the failing heart. The fourth mechanism, called the collateral effect, suggests that, when applied to the ischemic heart, cardiomyoplasty increases collateral blood flow to the myocardium, thereby benefiting cardiac function. However, the existence of unknown mechanisms is suggested by two phenomena that cannot be explained by these four mechanisms alone. Cardiomyoplasty was introduced as a method of direct cardiac assistance. However, it now appears that the relatively passive role of cardiomyoplasty in oxygen consumption saving and ventricular enlargement prevention may be of great importance.

Synthesis of sulfated octadecyl ribo-oligosaccharides with potent anti-AIDS virus activity by ring-opening polymerization of a 1,4-anhydroribose derivative

The synthesis and anti-AIDS virus activity of sulfated octadecyl ribofuranans with medium-range molecular weights have been investigated. Selective ring-opening polymerization of 1,4-anhydro-2,3-di-O-benzyl-alpha-D-ribopyranose with 10-20 mol% of boron triflouride etherate as a catalyst in a large amount of dichloromethane gave 2,3-di-O-benzyl-(1-->5)-alpha-D-ribofuranan in good yield. The molecular weight of the benzylated ribofuranan was in the range of 9 x 10(3) to 10 x 10(3). Debenzylation of the polymer followed by acetylation gave peracetylated (1-->5)-alpha-D-ribofuranans. The peracetylated ribofuranans were treated with octadecyl alcohol and a stannic chloride catalyst to afford acetylated ribofuranans having octadecyl groups at the reducing terminal. The molecular weights of the resulting acetylated octadecyl ribofuranans were below 9 x 10(3). Sulfation of the deacetylated octadecyl ribofuranans by piperidine-N-sulfonic acid in dry Me2SO gave sulfated octadecyl ribofuranans with molecular weights of 3 x 10(3) to 9 x 10(3) and sulfur contents of 13.0-16.2%. The sulfated octadecyl ribofuranans had potent anti-AIDS virus activity, EC50 = 0.6-2.5 micrograms/mL (a standard curdlan sulfate showed EC50 = 0.43 micrograms/mL), and low anticoagulant activity, 4-17 units/mg (a standard dextran sulfate, 22.7 unit/mg). Structural analysis of the ribofuranans was performed by NMR at 400 and 600 MHz.

Fusion of an ETS-family gene, EIAF, to EWS by t(17;22)(q12;q12) chromosome translocation in an undifferentiated sarcoma of infancy

EIAF is a newly isolated ETS-family gene that is located on 17q21 and codes for the adenovirus EIA enhancer-binding protein. In our chromosome analysis of 18 of the Ewing family of tumors and undifferentiated sarcomas, we found t(17;22)(q12;q12) in an MIC2 antigen-positive undifferentiated sarcoma of infancy. On Southern blot analysis, EWS and EIAF cDNA probes hybridized to the same rearranged band, indicating that an EWS-EIAF fusion gene was formed in the tumor. Further Southern blot analysis using four EIAF cDNA probes of different sizes showed that the breakpoint lies in the region upstream to the ETS domain of the EIAF gene. EIAF may be the fourth ETS-family gene to be identified forming a fusion gene with EWS. We assume that the RNA binding domain of EWS may have been replaced by the DNA binding domain of EIAF in the EWS-EIAF fusion protein as in other fusion proteins previously characterized in Ewing sarcoma and other types of sarcomas.

alpha-L-fucosyltransferases from radish primary roots

A novel alpha-L-fucosyltransferase capable of transferring L-fucose (L-Fuc) from GDP-L-Fuc to the O-2 of alpha-L-arabinofuranosyl residue (GDP-L-Fuc:alpha-L-arabinofuranoside 2-alpha-L-fucosyltransferase) has been found in the microsomal fraction of primary roots from 6-d-old radish (Raphanus sativus L.) seedlings. Enzyme activity was measured fluorometrically at 25 degrees C using a pyridylaminated trisaccharide, L-arabinofuranosylf alpha(1-->3)D-galactopyranosyl beta(1-->6)D-galactose (AraGalGal-PA) as the acceptor. This enzyme found in the microsomal fraction is maximally active at pH 6.8 and requires 0.1% (w/v) Zwittergent 3-16 and 5 mM Mn2+. Chemical and enzymatic analyses of fucosylated AraGalGal-PA confirmed the attachment of L-Fuc to the L-arabinofuranosyl (L-Araf) residue at O-2 by alpha-glycosidic linkage. Radiolabeling was used to assay L-Fuc transfer to L-Araf-containing galacto-oligomers and tamarind xyloglucan. The enzyme specific for the L-Araf residue undergoes development- and organ-specific expression in root tissue, whereas the L-Fuc transfer to tamarind xyloglucan can be detected in microsomal fractions from various organs in developing radish plants. Enzyme assays of membranes fractionated from microsomal fractions revealed that two distinct alpha-L-fucosyltransferases with different acceptor specificity are associated with Golgi membranes from primary roots, whereas hypocotyl Golgi membranes completely lack the enzyme specific for the L-Araf residue.

Linear skeletal muscle ventricle: a pilot study

We have developed a new skeletal muscle ventricle (LSMV) powered by linear contraction of the latissimus dorsi muscle (LD). This consists of two bellows of different diameters joined by a connector containing a valve. The smaller bellows is connected to the left atrium with a valve, and the larger bellows is connected to the aorta. The caudal tendon of the LD is attached to the connector. LD contraction pulls the connector to compress the larger bellows and to elongate the smaller bellows. This motion closes the valve in the connector, ejects blood in the larger bellows, and draws blood into the smaller bellows. LD relaxation allows aortic blood to regurge into the larger bellows. Therefore, the LD is stretched. In acute canine experiments, the stroke work and power output of the LSMV measured 0.214 J and 0.135 W with a filling pressure of 4.3 mm Hg.

The expression of Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase and alpha 2,6-linked sialoglycoconjugates in human brain tumors

CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase (alpha 2,6-ST) [EC 2.4.99.1] is developmentally regulated, shows a high degree of tissue specificity, and appears to play a role in oncogenic transformation and metastasis. In the present study, we have performed the first detailed analysis of the expression of alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates in human brain tumors. We used a polyclonal, monospecific anti-rat alpha 2,6-ST antibody and the alpha 2,6-linked sialic acid-specific lectin, Sambucus nigra agglutinin (SNA) for histochemical studies, and a human alpha 2,6-ST-specific cDNA probe for Northern analysis. Meningiomas, chordomas and craniopharyngiomas frequently expressed alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates. Among the different meningioma subtypes, meningothelial meningiomas stained more strongly with both anti-alpha 2,6-ST antibody and SNA than the fibroblastic and anaplastic meningiomas. On the other hand, all tumors of glial origin and medulloblastomas were virtually devoid of either alpha 2,6-ST or alpha 2,6-linked sialoglycoconjugate expression. Moreover, very weak to negligible expression of both alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates was observed in brain metastases. In conclusion, alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugate expression is associated with non-neuroectodermal epithelial-like tumors.

Binding of nonamer peptides to three HLA-B51 molecules which differ by a single amino acid substitution in the A-pocket

The interaction between 9-mer peptides and HLA-B51 molecules was investigated by quantitative peptide binding assay using RMA-S cells expressing human beta2-microglobulin and HLA-B51 molecules. Of 147 chemically synthesized 9-mer peptides possessing two anchor residues corresponding to the motif of HLA-B*5101 binding self-peptides, 27 peptides bound to HLA-B*5101 molecules. Pro and Ala at position 2 as well as Ile at position 9 were confirmed to be main anchor residues, while Gly at position 2 as well as Val, Leu, and Met at position 9 were weak anchor residues for HLA-B*5101. The A-pocket is suspected to have a critical role in peptide binding to MHC class I molecules because this pocket corresponds to the N-terminus of peptides and has a strong hydrogen bond formed by conserved Tyr residues. Further analysis of peptide binding to HLA-B*5102 and B*5103 molecules showed that a single amino acid substitution of Tyr for His at residue 171(B*5102) and that of Gly for Trp at residue 167 (B*5103) has a minimum effect in HLA-B51-peptide binding. Since previous studies showed that some HLA-B51 alloreactive CTL clones failed to kill the cells expressing HLA-B*5102 or HLA-B*5103, these results imply that the structural change of the A-pocket among HLA-B51 subtypes causes a critical conformational change of the epitope for TCR recognition rather than influences the interaction between peptides and MHC class I molecules.

Expression patterns of Raf-1 suggest multiple roles in tooth development

Raf-1, the product of proto-oncogene c-raf-1, has key roles in the signal transduction pathways within the cell. The molecular mechanisms of tooth development in the mouse embryo are not known in detail. We examined the expression of Raf-1 during subsequent tooth development by immunohistochemical analysis. In mouse embryos at days 12.5 post-coitum (p.c.), Raf-1 was expressed in the dental invaginating epithelium. At p.c. 13.5 (bud stage), Raf-1 was also expressed in the epithelial cells of the enamel organ, but not in the mesenchyme of the dental papilla. We added anti-proliferating cell nuclear antigen (PCNA) antibody as a marker for proliferating cells at early stages of tooth development. At p.c. 12.5 and p.c. 13.5, the staining patterns were very similar to that for Raf-1. At p.c. 15.5 (cap stage), Raf-1 could not be detected. At p.c. 17.5 (bell stage), Raf-1 was expressed in both the odontoblastic and subodontoblastic cells of the dental papilla. However, Raf-1 was not found in the epithelial cells of the enamel organ. We also added anti-type I collagen antibody as a marker for odontoblasts differentiation. The staining pattern for type I collagen antibody as a marker for odontoblasts differentiation. The staining pattern for type I collagen in odontoblasts was almost the same as for Raf-1. The results suggest that Raf-1 may play some roles in both cell proliferation and differentiation at different stages of tooth germ development.

Disappearance of AML1-MTG8(ETO) fusion transcript in acute myeloid leukaemia patients with t(8;21) in long-term remission

In a study of 23 patients with t(8;21)-associated acute myeloid leukaemia the AML1-MTG8 fusion transcript was present in the majority of serial samples obtained from 17 patients followed for up to 34 months after diagnosis, but was absent in samples from all six patients who had been in continuous complete remission for 61 months after allogeneic bone marrow transplantation (BMT), or for 52, 53, 123, 182 and 198 months, respectively, after courses of intensive chemotherapy. Previous studies showed that the AML1-MTG8 fusion transcript was present in most patients with this type of translocation in long-term remission. Our results indicate that blood cells of patients with t(8;21) in remission of over 10 years may not show the AML1-MTG8 fusion transcript, and that those of patients who have undergone allogeneic BMT or intensive chemotherapy may become fusion transcript-negative much earlier. Our study suggests that leukaemic cells with the AML1-MTG8 fusion transcript may survive for some time after courses of chemotherapy or BMT, but that they may eventually be eradicated by immunologic and other antileukaemic mechanisms.

The expression of CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase [EC 2.4.99.1] and glycoproteins bearing alpha 2,6-linked sialic acids in human brain tumours

The expression of CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase (alpha 2,6-ST) [EC 2.4.99.1] and glycoproteins bearing alpha 2,6-linked sialic acids were examined in primary human brain tumours and cell lines. 79% (19/24) of the meningiomas expressed alpha 2,6-ST mRNA, 42% (10/24) of which showed very high expression. alpha 2,6-ST mRNA expression was undetectable in normal brain tissue. In contrast, only 1/13 of the gliomas examined expressed detectable alpha 2,6-ST mRNA. Metastases to the brain did not express measurable amounts of alpha 2,6-ST mRNA. Less expression was found in malignant (i.e. anaplastic) compared to benign (i.e. meningothelial) meningiomas. Two-dimensional SDS-PAGE of glioma and meningioma proteins, followed by Sambucus nigra lectin staining, revealed the presence of a glycoprotein bearing alpha 2,6-linked sialic acids, M(r) = 53 kDa and a pI = 7.0 (MEN-1) that appeared in all seven of the meningiomas examined, but was expressed at barely detectable levels, if at all, in seven out of the seven glioblastomas examined. Thus, decreased alpha 2,6-ST expression may play a role in the aggressive nature of anaplastic meningiomas, but appears to be virtually absent in all tumours of glial origin.

A late-appearing Philadelphia chromosome in acute lymphoblastic leukemia confirmed by expression of BCR-ABL mRNA

We report two cases of acute lymphoblastic leukemia (ALL) with a late-appearing Philadelphia chromosome (Ph1), confirmed by the expression of BCR-ABL mRNA, using the reverse transcriptase/polymerase chain reaction (RT/PCR) technique. The first patient was a 10-year-old boy with precursor B cell type ALL-L1 (FAB classification). At diagnosis, no metaphase cells were found by chromosome analysis and BCR-ABL mRNA was not observed. At the beginning of relapse, which occurred after 7 months of complete remission, a normal karyotype was observed. At the terminal stage, leukemic cells with Ph1 and BCR-ABL mRNA for the P190 variety were observed. The second patient was a 12-year-old boy with immature T cell type ALL-L1. The metaphase cells showed a 9p- chromosome at diagnosis and Ph1 appeared in addition to 9p- at relapse. Hybrid mRNA for the P210 variety was detected only when Ph1 had developed. The blast cells with Ph1 were derived from the original leukemic clone through clonal evolution, since the same clonal rearrangements of IGH or TCRB were detected in leukemic cells obtained both at diagnosis and relapse in both patients. Thus, in both cases, Ph1 was detected only in the course of ALL along with expression of BCR-ABL mRNA. This observation also confirmed that, as in de novo Ph1-positive ALL, both the P190 and P210 varieties of BCR-ABL mRNA are observed in ALL with late-appearing Ph1.

Expression of vav proto-oncogene by nonhematopoietic trophoblast cells at the human uteroplacental interface

Vav is a signal transducing molecule containing SH2 and SH3 domains and a guanine nucleotide releasing factor-like domain. Its expression is thought to be highly specific for hematopoietic cells. Here we describe the expression of vav transcripts in human nonhematopoietic trophoblasts. By northern blotting, expression of 2.8-kb vav mRNA was detected in human decidual, placental, and chorionic villous tissues and in a choriocarcinoma cell line BeWo. By in situ hybridization, vav mRNA was found to be expressed in the cytotrophoblast shell and columns and in the extravillous trophoblasts in the maternal decidua from the first through third trimesters. Vav mRNA was also detected in villous syncytiotrophoblasts during the second and third, but not the first, trimesters. When 1 microM oligodeoxynucleotide antisense to the vav mRNA was added to the medium, growth of BeWo cells was significantly inhibited. These results suggest that vav plays an important role for successful implantation and placental development by regulating development of trophoblasts.

Gene therapy of hepatoma: bystander effects and non-apoptotic cell death induced by thymidine kinase and ganciclovir

A retroviral vector carrying herpes simplex virus thymidine kinase gene was constructed, and transfected into the psi 2 packaging cells. The replication-defective retrovirus produced by this cell line (psi 2 tkn cells) was transduced into XC rat hepatoma cells, from which a cell line (XCtkn2) highly sensitive to ganciclovir was cloned. Ganciclovir suppressed the growth of XCtkn2 hepatoma and psi 2tkn cells. Both of these HSV-tk-carrying cells treated with ganciclovir showed potent 'bystander effect' on co-culturing with genetically unmodified XC hepatoma cells. In addition, intratumoral injection of XCtkn2 and psi 2tkn cells into the XC hepatomas transplanted in nude mice and subsequent ganciclovir administration suppressed in vivo growth of the hepatomas. Flow cytometry disclosed that the ganciclovir-treatment increased the relative number of XCtkn2 hepatoma and psi 2tkn cells at the G2 phase of the cell cycle. However, the nuclear fragmentation and internucleosomal DNA cleavage were not observed, indicating that the death of XCtkn2 hepatoma and psi 2tkn cells treated with ganciclovir was not apoptotic.

Combined drug therapy with diltiazem, dextran, and hydrocortisone (DDH therapy) for late cerebral vasospasm after aneurysmal subarachnoid hemorrhage: assessment of efficacy and safety in an open clinical study

Late cerebral vasospasm after subarachnoid hemorrhage (SAH) is a disastrous phenomenon for the patients and a definite treatment has not been established. We studied 48 consecutive patients receiving high-dose diltiazem (5 micrograms/kg/min) injection combined with dextran and hydrocortisone to late cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). All but 2 patients underwent surgery within 72 hours after SAH. Diltiazem was continuously given via a central venous line for up to 2 weeks in conjunction with simple cisternal drainage. 5% of dextran solution (500 ml/day) was infused for 7-10 days. Hydrocortisone was given 1,600 mg on the first day, then the dose was gradually decreased over 14 days. Symptomatic vasospasm (SVS) occurred in 5 patients (10.4%), 4 patients recovered, but 1 had severe neurological deficit. A low density area on CT-scan was observed in 2 patients. Thirty patients (62.5%) had good recovery, 10 patients (20.8%) had moderate disability, 3 (6.3%) had severe disability and 3 (6.3%) had vegetative survival. Two patients died of the initial brain damage. There were no severely hypotensive side effects. However, 3 patients showed atrioventricular blockage on electrocardiogram. These side effects subsided after the dose of the drug was decreased or administration was stopped altogether. These findings show that high-dose calcium antagonist diltiazem therapy combined with dextran and hydrocortisone injection is safe and effective for prevention of late cerebral symptomatic vasospasm after SAH.

Antagonistic peptides against human anaphylatoxin C5a

Multivalent synthetic peptides derived from C5a were prepared in order to examine their effects on the C5a receptor (C5aR). Multiple antigen peptide (MAP) of the C5a C-terminal region (MAP61-74) bound to cells expressing C5aR with high affinity. On the other hand, N-terminal peptides (MAP3-16 and MAP12-26) and one with a sequence from the mid-portion of C5a (MAP37-53) did not bind to the cells. In addition, MAP61-74 inhibited Ca2+ mobilization and release of beta-hexosaminidase by C5a from dibutyryl cAMP-activated U937 cells. This Ca2+ mobilization was also inhibited by MAP12-26 and Mono61-74, the monomeric C-terminal peptide. Taken together, these data indicate that C5a binds to the C5aR via its C-terminal region. Furthermore, MAP61-74, a 14mer peptide that has additional amino acids at the N-terminal compared with the C-terminal octapaptide, can bind to C5aR and can be considered an antagonist of C5a which may prove useful as an agent for controlling the allergic response caused by complement activation.

Neuroendocrine tumors of the liver and pancreas associated with elevated serum prostatic acid phosphatase

A 58-year-old man was revealed to have multiple liver tumors with elevated prostatic acid phosphatase (PAP) during a medical examination. The tumors were of neuroendocrine nature, but no abnormal findings were obtained in other organs in which neuroendocrine tumors develop frequently. Repeated transarterial embolization was partially effective. However, the tumors became resistant to the therapy three years later, continued growing and ruptured. Autopsy disclosed neuroendocrine tumors in the pancreas, which were immunohistologically positive for PAP. Neuroendocrine tumors of the pancreas and liver producing PAP are rare; this case is reported with a review of literature.

Expression of Gal beta 1,4GlcNAc alpha 2,6-sialyltransferase and alpha 2,6-linked sialoglycoconjugates in normal human and rat tissues

We performed histochemical studies on normal human and rat tissues using anti-Gal beta 1,4GlcNAc alpha 2,6-sialyltransferase (alpha 2,6-ST) antibody and Sambucus nigra agglutinin (SNA). alpha 2,6-ST and its products were detected in almost all tissues examined. However, the staining intensities varied significantly with different cell types. Some secretory epithelial cells, such as hepatocytes and choroid plexus cells, were vividly stained with either anti-alpha 2,6-ST or SNA. In several cell types the intensity of alpha 2,6-ST staining did not always correlate with SNA stainability. Neurons and gastrointestinal epithelia were rarely stained with SNA, even though they were positive for alpha 2,6-ST. In contrast, the endothelial cells of blood vessels strongly reacted with SNA despite their weak alpha 2,6-ST expression. The precise physiological roles played by alpha 2,6-linked sialylated glycoconjugates have been unclear. However, the findings described here lend further support to their important role in cell growth and differentiation, since immature blood cells, including megakaryocytes in bone marrow, were intensely stained with anti-alpha 2,6-ST and SNA, and SNA reaction products were primarily observed in the basal and suprabasal layers of the stratified epithelia rather than in the more differentiated upper layers. In view of the vivid reactivity of anti-alpha 2,6-ST in the decidual cells of the placenta, it seems likely that alpha 2,6-ST expression is under hormonal control.