Gene Literature Dashboard

During development of the rat central nervous system, neural cell adhesion molecule (NCAM) mRNAs containing in the extracellular domain a 30-bp alternative exon, here named VASE, replace RNAs that lack this exon. The presence of this alternative exon between previously described exons 7 and 8 changes the predicted loop structure of the derived polypeptide from one resembling an immunoglobulin constant region domain to one resembling an immunoglobulin variable domain. This change could have significant effects on NCAM polypeptide function and cell-cell interaction. In this report we test multiple rat tissues for the presence of additional alternative exons at this position and also examine the regulation of splicing of the previously described exon. To sensitively examine alternative splicing, polymerase chain reactions (PCRs) with primers flanking the exon 7/exon 8 alternative splicing site were performed. Four categories of RNA samples were tested for new exons: whole brain from embryonic day 11 to adult, specific brain regions dissected from adult brain, clonal lines of neural cells in vitro, and muscle cells and tissues cultured in vitro and obtained by dissection. Within the limits of the PCR methodology, no evidence for any alternative exon other than the previously identified VASE was obtained. The regulation of expression of this exon was found to be complex and tissue specific. Expression of the 30-bp exon in the heart and nervous system was found to be regulated independently; a significant proportion of embryonic day 15 heart NCAM mRNAs contain VASE while only a very small amount of day 15 nervous system mRNAs contain VASE. Some adult central nervous system regions, notably the olfactory bulb and the peripheral nervous system structures adrenal gland and dorsal root ganglia, express NCAM which contains very little VASE. VASE is undetectable in NCAM PCR products from the olfactory epithelium. Other nervous system regions express significant quantities of NCAM both with and without VASE. Clonal cell lines in culture generally expressed very little VASE. These results indicate that a single alternative exon, VASE, is found in NCAM immunoglobulin-like loop 4 and that distinct tissues and nervous system regions regulate expression of VASE independently both during development and in adult animals.

Sixty-two primary breast carcinomas were analyzed for estrogen receptor (ER) by both the dextran-coated charcoal (DCC) technique and estrogen receptor immunocytochemical assay (ER-ICA) on cryostat and permanent sections. Paraffin sections of formalin-fixed breast tissue underwent DNase pretreatment to expose the nuclear antigenic site as described by P. Shintaku and J. H. Said (Am J Clin Pathol 87:161, 1987). The results of immunocytochemical staining agreed with those of the DCC biochemical assay in 89% of paraffin-sectioned tissue and in 94% of the cryostat sections. Comparison of the results of ER-ICA on permanent and frozen sections showed 85% agreement (kappa statistic = 0.704). This study suggests that ER can be demonstrated immunocytochemically on paraffin-sectioned breast tissue. However, although highly specific, immunoperoxidase determination on paraffin-embedded tissue is less sensitive than that on frozen tissue. The commercial source of DNase, length of incubation, and tissue fixation are important factors in the demonstration of ER immunoreactivity. The assay may offer an alternative for assessment of ER when tissue is not suitable or available for biochemical assay or conventional cytochemical analysis.

Tissue samples from fourteen consecutive (8 male: 6 female) acoustic neuromas were assayed for hormone receptors using either a monoclonal antibody (MA), dextran coated charcoal (DCC) or isoelectric focusing (IEF) technique. In this series there were no unequivocally positive results, a finding at variance with previously published results.

Recent advances in understanding the molecular genetics of common adult tumors have indicated that multiple genetic alterations including the activation of oncogenes and the inactivation of tumor suppressor genes are important in the pathogenesis of these tumors. Loss of heterozygosity is a hallmark of tumor suppressor gene inactivation and has been used to identify chromosomal regions that contain these genes. We have examined allelic loss in the most common tumor in men, prostate cancer. Twenty-eight prostate cancer specimens have been examined for loss of heterozygosity at 11 different chromosomal arms including 3p, 7q, 9q, 10p, 10q, 11p, 13q, 16p, 16q, 17p, and 18q. Fifty-four percent (13/24) of clinically localized tumors and 4 of 4 metastatic tumors showed loss of heterozygosity on at least one chromosome. Chromosomes 16q and 10q exhibited the highest frequency of loss of heterozygosity with 30% of tumors showing loss at these chromosomes. These data demonstrate that allelic loss is a common event in prostate cancer and suggest that chromosomes 16q and 10q may contain the sites of tumor suppressor genes important in the pathogenesis of human prostate cancer.

The activated c-Ha-ras oncogene induced AP1-site DNA-binding activity in F9 cells. This induction appeared to be due, at least in part, to the induction of c-jun transcription. Both activated c-Ha-ras and c-jun induced the differentiation of F9 cells to endoderm-like cells. Thus, AP1 appears to play a key role in the initial stage of F9 cell differentiation.

Hypogonadism is a common finding in idiopathic hemochromatosis. Most studies have localized the defect to either the pituitary gland or the testes. We describe a case with evidence that favors the likely concomitant involvement of the hypothalamus as a factor in the observed hypogonadism. A clinically hypogonadal male with hemochromatosis had a low testosterone concentration with inappropriately normal serum LH levels. Leydig cell function was intact, as demonstrated by a normal increase in serum testosterone following HCG administration. However, although the pituitary secretion of LH was normal in response to GnRH stimulation, clomiphene administration did not produce an increase in LH and FSH, suggesting that there was a defect in the hypothalamic GnRH response. Since the FSH and prolactin responses to stimulatory testing were inadequate, coexisting pituitary dysfunction was likely also present. We conclude that this man had hypogonadism with laboratory evidence for a combined defect in hypothalamic and pituitary function.

The Int proteins of bacteriophages HK022 and lambda promote recombination between phage and bacterial attachment sites. Although the proteins and attachment sites of the two phages are similar, neither protein promotes efficient recombination between the pair of attachment sites used by the other phage. To analyze this difference in specificity, we constructed and characterized chimeric attachment sites in which segments of one site were replaced with corresponding segments of the other. Most such chimeras recombined with appropriate partner sites in vivo and in vitro, and their differential responses to the Int proteins of the two phages allowed us to locate determinants of the specificity difference in the bacterial attachment sites and a central segment of the phage attachment sites. The location of these determinants encompasses three of the four core-type binding sites for lambda Int: C, B, and most importantly, B'. The regions corresponding to the C' core binding site and the arm-type binding sites of lambda Int play no role in the specificity difference and, indeed, are well conserved in the two phages. We found, unexpectedly, that the effect of replacement of an Int-binding region on the recombinational potency of one chimeric site was reversed by a change of partner. This novel context effect suggests that postsynaptic interactions affect the specificity of recognition of attachment sites by Int.

No abstract available.

Dystrophic cardiac calcinosis (DCC) is a frequent finding in DBA/2, C3H and BALB/c mice and its etiology is not known. Previous studies have speculated that myocardial necrosis is involved in the pathogenesis of DCC. In this study, cardiac necrosis was induced in DBA/2, C3H and C57BL/6 mice by freeze-thaw injury through the abdominal diaphragm. Four weeks after freeze-thawing, the mice were sacrificed and the hearts and diaphragms were examined. In response to injury, cardiac mineralization was present only in DBA/2 and C3H mice. The myocardium of C57BL/6 mice (control strain) healed by fibrosis without mineralization, the normal response of the myocardium to injury. Calcified diaphragms also were present at the site of freeze-thaw injury in DBA/2 and C3H mice, which is supportive evidence that a systemic abnormality is involved in the pathogenesis of DCC. The conclusion from this study is that the pathogenesis of DCC in DBA/2 and C3H mice is multifactorial and involves both myocardial necrosis and an abnormal response to injury.

Female sex steroid receptors were examined in 50 human cerebral meningiomas. For estrogen receptors, high-affinity binding sites (dissociation constant (Kd): 0.05 to 0.2 nM) were found in the cytosolic fraction with a capacity of less than 4 fmol/mg protein in 10 meningiomas using a dextran-coated charcoal (DCC) assay. In the same cytosolic fraction, the solid-phase enzyme immunoassay revealed only one cytosol with a positive colorimetric reaction equal to 5 fmol/mg protein. However, in the nuclear compartment, none of the tumors stained positively for estrogen receptors with immunohistochemical techniques. In addition, the most convincing evidence for the absence of estrogen receptors was obtained by in situ hybridization using an oligonucleotide probe complementary to a fraction of the human receptor messenger ribonucleic acid (mRNA). In none of the 50 meningiomas was the expression of estrogen mRNA coding for the estrogen receptor detected. For progesterone receptors, high-affinity binding sites (Kd: 0.3 to 2.6 nM) were found in 49 of the 50 tumors using a DCC assay. In the same cytosols, solid-phase enzyme immunoassay revealed that each tumor was positive for progesterone receptors. However, in the nuclear compartment, only five tumors had partially positive staining for progesterone receptors with immunohistochemical techniques. Within the confines of this study, it is concluded that: 1) the estrogen receptor is generally absent in meningioma tissue, and 2) the progesterone receptor is mainly absent in the nuclear compartment, leading to the conclusion that the cytosolic progesterone receptor may be an inactive form. This study suggests that female sex steroid receptors are not primarily involved in the proliferative rate of cerebral meningiomas and that they are of no current significance as markers for adjuvant medical therapy of most meningiomas.

An hereditary abnormal antithrombin III (ATIII Geneva) with defective heparin cofactor activity was characterized by DNA single strand amplification and subsequent direct sequencing. ATIII Geneva was found to have a G to A transition in Exon IIIa leading to an Arg-129 to Gln mutation. This amino acid is part of the ATIII region comprising residues 114-154, which contains the highest proportion of basic residues (Arg or Lys), and is known from chemical modification studies to be involved in heparin binding. The variant protein did not bind heparin-Sepharose and was isolated from the propositus plasma by immunoaffinity chromatography. High affinity (for ATIII) heparin had only a minimal effect on thrombin and activated factor X inhibition by the purified abnormal ATIII. Taken together, these results demonstrate an important role for Arg-129 in the binding and interaction of ATIII with heparin of high affinity. We propose that a cooperation between Lys-125, Arg-129, Lys-136, and Arg-47 exposed at the surface of the inhibitor allows the binding of the essential pentasaccharide domain of heparin which is specific for the ATIII interaction.

To determine whether physicians in an academic medical center excluded hemochromatosis as a diagnosis in a population of patients with mildly elevated liver enzyme values, we reviewed 100 charts of patients with both aspartate aminotransferase and alkaline phosphatase levels that were less than twice the upper limit of normal. We analyzed each chart to determine if hemochromatosis would have been excluded by a subsequent workup. Those patients who did not have a complete workup were assigned to one of three categories: (1) no mention was made of abnormal liver enzyme values; (2) liver enzyme values were ascribed to some condition other then hemochromatosis and no definitive workup was done; and (3) the condition of the patient was so poor that assessment did not seem indicated. Ninety of 100 patients were not given a workup to exclude hemochromatosis. Physicians often ignore mild elevations in liver enzyme values.

The effect of thrombin was tested in vitro on rings of bovine retinal small arteries (internal diameter approximately 200 microns). Cumulative addition of thrombin (0.001-10 units/ml) induced a variable concentration-dependent contraction of the retinal arteries. The contractions were slow in onset and reached a plateau after 5-8 minutes when thrombin was added cumulatively to the organ bath. Two vessels remained contracted greater than 1 hour after wash-out of thrombin. Maximum vessel contraction induced by thrombin was equal to 43% of the vessel Emax (1.36 N/m), with an effective concentration at the 50% level of 0.04 units/ml. Vessel contraction induced by 1 unit/ml of thrombin was, in contrast, transient, reaching a maximum within 2-4 minutes. Thereafter the vessel tension declined again almost back to baseline within the next 10-20 minutes. Contractions to thrombin could not be repeated nor could it be elicited with thrombin inactivated with heat or antithrombin-III. Treatment of vessels with 10(-6) M phenoxybenzamine had no effect on the thrombin-induced vessel response. These findings indicate that the contractile effect of thrombin depends on its catalytic activity. Indomethacin at a concentration of 10(-5) M did not affect the thrombin-induced vessel response. Methylene blue at a concentration of 3 X 10(-6) M potentiated the thrombin-induced response in the larger, greater than 200-microns diameter retinal arteries. The ensuing relaxation of the arteries, after maximal tone was reached, was slower than in the control.(ABSTRACT TRUNCATED AT 250 WORDS)

Masking protein (MP), which neutralizes the activity of transforming growth factor type beta 1 (TGF-beta 1), is composed of a dimeric N-terminal part of a TGF-beta 1 precursor of Mr 39,000 and an unknown large subunit of Mr 105,000-120,000. The deduced primary structure of the MP large subunit was elucidated by determining the nucleotide sequence of its cDNA. The cDNA encodes a prepro-precursor of 1712 amino acid residues with a calculated Mr of 186,596. The mature large subunit seems to be derived proteolytically from a prepro-precursor and the calculated Mr is 91,606. The precursor has seven N-linked glycosylation sites and an unusual structure containing 18 epidermal growth factor-like domains and four cysteine-rich internal repeats. The large subunit mRNA is synthesized in parallel with the expression of TGF-beta 1 mRNA in various rat tissues.

In this study, blood coagulation and fibrinolytic parameters were measured in maternal blood and fetal umbilical cord blood in 200 normal pregnant women and in 46 with severe toxemia of pregnancy (Toxemia), and the relationships between fetal growth and concentrations protein C (PC), antithrombin-III (AT-III) and alpha 2-plasmin inhibitor (alpha 2-PI) were studied. 1. Significant increases in fibrin degradation products (FDP) and in plasminogen (Plg), AT-III and PC were found in maternal blood of Toxemia. A significant increase in AT-III and a decrease in alpha 2-PI and PC were observed in cord blood from these patients. 2. The platelet count (Pl) tended to be low in patients with Toxemia complicated by fetal growth retardation (IUGR). 3. Pl and fibrinogen (Fib) tended to be high in Toxemia complicated by normal fetal growth. 4. PC increased from early pregnancy, and a further increase was observed in the puerperium. 5. The PC concentration correlated with the AT-III but not with the alpha 2-PI concentration in maternal blood. 6. PC in cord blood was lower than that in maternal blood, and was correlated with AT-III and alpha 2-PI. 7. In patients with Toxemia, PC was reduced in both maternal and cord blood, and this correlated with AT-III as well as alpha 2-PI in maternal blood. 8. PC was low in Toxemia complicated by hypertension and proteinuria. These results suggest the involvement of FDP, AT-III, PC and Plg in the pathogenesis of Toxemia, and that the Pl, Fib, FDP and alpha 2-PI concentrations are related to fetal growth. Therefore, the PC and AT-III concentrations appeared to be a useful index for the blood coagulation and fibrinolysis in pregnant women and appeared to be important factors in the degree of Toxemia and IUGR.

In order to investigate the presence of androgen insensitivity in patients with male infertility, intratubular androgen receptor (AR) was measured in patients with idiopathic oligozoospermia and azoospermia. The specimens were obtained by testicular biopsy or orchiectomy from 56 patients with oligozoospermia and 5 with azoospermia for clinical study, and 17 with varicocele, 22 with vas disorders and prostatic cancer, which had a mean germinal epithelium score count of 8.5 or greater by the method of Johnsen (JSC) for deciding the cut-off levels, as the control group. Intratubular AR was measured by a 5-point micro-receptor assay, an exchange assay with the DCC method, using 40 microliters of each sample extract and 3H-methyltrienolone as the ligand. The genital skin AR assay was also conducted simultaneously in 34 patients. The results were as follows: 1) No significant correlation was noted between intratubular ARs and genital skin ARs. 2) The maximum binding (Bmax) of AR in the total intratubular extract was intermediate between that of the cytosol fraction and the nuclear extract. 3) Significant correlation was noted between the Bmax of ARs by the micro-receptor assay and those by the conventional assay. 4) The Bmax of AR in the control group (n = 22) was 30.38 +/- 9.89 fmol/mg protein (mean +/- S.D.) and was over 11 fmol/mg protein in all cases. Therefore, 11 fmol/mg protein was decided as the cut-off level for androgen insensitivity. 5) Comparative studies were undertaken between two groups, i.e., low AR group and normal AR group, with AR as a parameter for male infertility.(ABSTRACT TRUNCATED AT 250 WORDS)